Dalhousie University is a public research university in Nova Scotia, Canada, with three campuses in Halifax, and a fourth in Bible Hill. Dalhousie offers more than 4,000 courses and 180 degree programs in twelve undergraduate, graduate, and professional faculties. The university is a member of the U15, a group of research-intensive universities in Canada.Dalhousie was established as a nonsectarian college in 1818 by the Lieutenant Governor of Nova Scotia, George Ramsay, 9th Earl of Dalhousie, after whom the university was named. The college did not hold its first class until 1838, until then operating sporadically due to financial difficulties. It reopened for a third time in 1863 following a reorganization which brought a change of name to "The Governors of Dalhousie College and University". The university formally changed its name to "Dalhousie University" in 1997 through provincial legislation, the same legislation which had merged the institution with the Technical University of Nova Scotia.The Dalhousie library system currently operates the largest library in Atlantic Canada, as well as holds the largest collection of agricultural resource material in the region. The university operates a total of fourteen residences. There are currently two student unions that represent student interests at the university, the Dalhousie Student Union, and the Dalhousie Association for Graduate Students. Dalhousie's varsity teams, the Tigers, compete in the Atlantic University Sport conference of Canadian Interuniversity Sport. Dalhousie’s Faculty of Agriculture varsity teams are the Dalhousie Rams, and compete in the ACAA and CCAA.Dalhousie is a coeducational university with more than 18,000 students and over 110,000 alumni. Notable alumni include government officials, academics, business leaders and 89 Rhodes Scholars. The university ranked 244th in the 2013 QS World University Rankings, 251-275th in the 2012-2013 Times Higher Education World University Rankings, and 201–300th in the 2012 Academic Ranking of World Universities. Dalhousie is a centre for marine research, and is host to the headquarters of the Ocean Tracking Network. Wikipedia.
Dalhousie University | Date: 2016-10-28
The present invention provides a method for removing a tattoo in a region of skin the method comprises administering to a least a portion of the tattoo, and a composition comprising an effective amount of a bisphosphonate and at least one pharmaceutically acceptable excipient to at least cause fading of the tattoo in said region.
Massachusetts Institute of Technology and Dalhousie University | Date: 2016-08-09
Amblyopia is a prevalent form of visual impairment that generally arises during infancy and early childhood when inputs to the visual cortex form the two eyes are poorly balanced. Disclosed herein are methods involving retinal inactivation of at least one retina to treat visual impairment in the form of amblyopia or other conditions.
Xie S.,Dalhousie University |
Kolokolnikov T.,Dalhousie University
Nonlinearity | Year: 2017
We consider a single spot solution for the Schnakenberg model in a two-dimensional unit disk in the singularly perturbed limit of a small diffusivity ratio. For large values of the reaction-time constant, this spot can undergo two different types of instabilities, both due to a Hopf bifurcation. The first type induces oscillatory instability in the height of the spot. The second type induces a periodic motion of the spot center. We use formal asymptotics to investigate when these instabilities are triggered, and which one dominates. In the parameter regime where spot motion occurs, we construct a periodic solution consisting of a rotating spot, and compute its radius of rotation and angular velocity. Detailed numerical simulations are performed to validate the asymptotic theory, including rotating spots. More complex, non-circular spot trajectories are also explored numerically. © 2017 IOP Publishing Ltd & London Mathematical Society.
Andrew M.K.,Dalhousie University
Healthcare Papers | Year: 2016
Improving dementia care in Canada is a challenge to which we must rise. Dementia care strategies with a strong community focus are a key means of doing so. This paper outlines and expands upon the following five core areas that will contribute to the success of dementia care strategies: 1) the relationship between frailty and dementia is critical to understanding and addressing dementia risk and management; 2) social circumstances are important to formally consider, both as risk factors for adverse outcomes and as practical factors that contribute to care and support planning; 3) a dementia care strategy must span the continuum of care, which has important ramifications for our systems of primary, acute and long-term care; 4) prevention and public education are essential components of dementia care strategies; 5) research and evaluation are critically important to any dementia care strategy, and must be seen as core components as we strive to learn what works in dementia care. Given that a coordinated effort is needed, Canada needs to join other countries that have recognized dementia as a momentous challenge to national and global health. The time for a comprehensive national dementia care strategy is now.
Butler J.P.,Dalhousie University |
Beaumont C.,Dalhousie University
Earth and Planetary Science Letters | Year: 2017
The plate tectonic setting in which proto-ophiolite ‘oceanic’ lithosphere is created remains controversial with a number of environments suggested. Recent opinions tend to coalesce around supra-subduction zone (SSZ) forearc extension, with a popular conceptual model in which the proto-ophiolite forms during foundering of oceanic lithosphere at the time of spontaneous or induced onset of subduction. This mechanism is favored in intra-oceanic settings where the subducting lithosphere is old and the upper plate is young and thin. We investigate an alternative mechanism; namely, decoupling of the subducting oceanic lithosphere in the forearc of an active continental margin, followed by subduction zone (trench) retreat and creation of a forearc oceanic rift basin, containing proto-ophiolite lithosphere, between the continental margin and the retreating subduction zone. A template of 2D numerical model experiments examines the trade-off between strength of viscous coupling in the lithospheric subduction channel and net slab pull of the subducting lithosphere. Three tectonic styles are observed: 1) C, continuous subduction without forearc decoupling; 2) R, forearc decoupling followed by rapid subduction zone retreat; 3) B, breakoff of subducting lithosphere followed by re-initiation of subduction and in some cases, forearc decoupling (B-R). In one case (BA-B-R; where BA denotes backarc) subduction zone retreat follows backarc rifting. Subduction zone decoupling is analyzed using frictional-plastic yield theory and the Stefan solution for the separation of plates containing a viscous fluid. The numerical model results are used to explain the formation of Xigaze group ophiolites, southern Tibet, which formed in the Lhasa terrane forearc, likely following earlier subduction and not necessarily during subduction initiation. Either there was normal coupled subduction before subduction zone decoupling, or precursor slab breakoff, subduction re-initiation and then decoupling. Rapid deep upper-mantle circulation in the models during subduction zone retreat can exhume and emplace material in the forearc proto-ophiolite from as deep as the mantle transition zone, thereby explaining diamonds and other 10–15 GPa UHP phases in Tibetan ophiolites. © 2017 Elsevier B.V.
Zheng L.,Dalhousie University |
Obrovac M.N.,Dalhousie University
Electrochimica Acta | Year: 2017
The Na0.9Ni0.45MnxTi0.55-xO2 (0 ≤ x ≤ 0.55) series of layered oxides was synthesized using a solid-state method and the materials in this series were studied as positive electrode materials in sodium cells. All compositions resided in a phase pure O3 solid solution. Compared to the Ti-free composition, Na0.9Ni0.45Mn0.4Ti0.15O2 has improved capacity retention without sacrificing reversible capacity and average voltage. Na0.9Ni0.45Mn0.4Ti0.15O2 delivers ∼197 mAh/g of reversible capacity in a voltage range of 1.5-4.5 V with an average voltage of ∼3.27 V. Energy density available based on metallic sodium is estimated to be approximately 643 Wh/kg or 2805 Wh/L. Increasing the Ti content beyond this composition results in increased average voltage, increased polarization and a reduction in cycling performance. © 2017 Elsevier Ltd
Cutler G.C.,Dalhousie University |
Scott-Dupree C.D.,University of Guelph
BioScience | Year: 2016
The issues of pesticides and the risks they pose to bees are hotly debated. A key area of contention is the "trustworthiness" of industry-funded studies that are used by regulatory agencies in their bee-pesticide risk assessments. Although some argue that research into pesticide safety should be funded only by government or independent bodies, systems such as good laboratory practice (GLP) help ensure the quality and transparency of regulatory data and reports, irrespective of the fact that industry may be the primary funding source. Here, we briefly describe some of our experiences in conducting GLP field studies examining the effects of neonicotinoid insecticides on honey bees, providing examples of the high degree of quality-assurance oversight, while reminding readers that so-called independent, peer-reviewed research has multiple potential shortcomings. © The Author(s) 2016. Published by Oxford University Press on behalf of the American Institute of Biological Sciences. All rights reserved.
Doolittle W.F.,Dalhousie University
Journal of Theoretical Biology | Year: 2017
The Gaia hypothesis of James Lovelock was co-developed with and vigorously promoted by Lynn Margulis, but most mainstream Darwinists scorned and still do not accept the notion. They cannot imagine selection for global stability being realized at the level of the individuals or species that make up the biosphere. Here I suggest that we look at the biogeochemical cycles and other homeostatic processes that might confer stability - rather than the taxa (mostly microbial) that implement them - as the relevant units of selection. By thus focusing our attentions on the "song", not the "singers", a Darwinized Gaia might be developed. Our understanding of evolution by natural selection would however need to be stretched to accommodate differential persistence as well as differential reproduction. © 2017 Elsevier Ltd.
Mosbah H.,Dalhousie University |
El-Hawary M.E.,Dalhousie University
Electric Power Systems Research | Year: 2017
A powerful metaheuristic technique is proposed that uses a mathematical concept called Stochastic Fractal Search (SFS) to ensure fast convergence along with accuracy. This paper intends to determine the optimal set of multilayer perceptron neural network (MLP) parameters (weights and thresholds) to improve the performance of MLP by using the SFS technique. The SFS is used because of its effective search in finding the global minima and therefore, it avoids the MLP neural network trapped in local minima. The hybrid approach (MLP-SFS) is applied to solve the dynamic state estimation (DSE) problem at the filtering stage. DSE amalgamates forecasting procedure with measurement data to precisely assess the system state. The approach classifies the process into three stages. In the first stage, a short term hourly load forecasting is applied using support vector machine (STLF-SVM) for time series to forecast the unavailable load data due to communication failure from the previous hourly historical data load. The second stage constitutes an optimal power flow (OPF) that is used to determine the minimum cost generation dispatch to serve the given load and convert the obtained loads, and generations into measurement data. The third stage has a filtering process, which uses SFS technique to optimize the MLP neural network parameters (weights and thresholds) to estimate the system state. The hybrid MLP-SFS is used to find the optimal connection weights and thresholds for the MLP neural network. Following this, a simple backpropagation neural network (BPN) will adjust the final parameters. The approach is tested on IEEE 14-and 118-bus systems using realistic load patterns from the New York Independent System Operator (NYISO) under several scenarios of measurement error and communication failure. The mean absolute percentage error index of the system state (phase and magnitude voltage) is used to determine the accuracy of the approach (MLP-SFS). Results of the proposed approach (MLP-SFS) are compared with non-optimized MLP (random weights and thresholds) and other methods, such as, optimized MLP based on genetic algorithm (MLP-GA) and Particle Swarm Optimization (MLP-PSO) individually. The results indicate that the hybrid (MLP-SFS) increases the precision by about 20%–50% and reduces the computational time around by 30%–50%, which is good for real-time applications, such as, security assessment and contingency evaluation. Details of the models of generation and distribution level are not part of the state estimation in the high voltage transmission problems. © 2017 Elsevier B.V.
Soomai S.S.,Dalhousie University
Marine Policy | Year: 2017
Understanding how information flows between scientific and decision-making communities is essential for the creation of effective strategies to link scientific advice to management decisions. Interviews of scientists and managers in two inter-related fisheries management organizations – the Department of Fisheries and Oceans (DFO) and the Northwest Atlantic Fisheries Organization (NAFO) – and direct observations at science and management meetings revealed important organizational characteristics that influence the production, communication, and use of scientific information in decision-making. Formal processes for communicating scientific advice to managers – DFO's Canadian Scientific Advisory Secretariat (CSAS) and NAFO's Fisheries Commission's Request for Advice – demonstrate the use of credible, relevant, and legitimate advice for operational decision-making for fisheries management. Such defined processes, in addition to governmental bureaucracy, departmentalization, and de-centralization, can limit communication as highlighted for Canada as a Contracting Party to NAFO. Administrative mechanisms can pose challenges to implementing ecosystem approaches to fisheries management (EAF) and to addressing the impacts of climate change. Emerging organizational structures and behaviours facilitate communication at the science-policy interface, within and between the organizations, thereby improving understanding of science and management needs and promoting trust relationships between scientists and managers. The involvement of multiple stakeholders in the information pathways addresses concerns about scientific uncertainty in assessment advice. A linear model of information flow typifies operational decision-making; however, collaborative models that incorporate different types of information, apart from fisheries science, are required to enable ecosystem-based management. The characteristics of the information pathways are particularly relevant as the organizations address their EAF mandates. © 2017
Simone M.,Dalhousie University |
Grant J.,Dalhousie University
Estuarine, Coastal and Shelf Science | Year: 2017
A geochemical proxy often utilized in marine benthic health assessment is the depth of the apparent redox potential discontinuity (aRPD), a visual signature representing the transition from lighter oxidized to darker reduced sediments. Traditionally this boundary is defined by the redox potential discontinuity (RPD), a 0 mV isovolt measured by platinum electrodes. In order to verify the use of visual transitions as a proxy for electrochemical RPD, these measurements were compared in subtidal sandy muds (13.5 m depth) in coastal Nova Scotia, Canada. The apparent RPD was measured from sediment profile imagery (SPI) images and diver-retrieved cores. Pre-drilled cores with vertical holes allowed for the coupling of electrochemical and visual boundary measurements in the same sample. The mean discrepancy of the RPD is 0.6 ± 2.6 cm (mean ± maximum variation) above the aRPD depth. The Eh range at the aRPD, −14.94 ± 52.21 mV, encompassed the 0 mV isovolt, suggesting the aRPD can be applied as a sound proxy for the transition between redox states. © 2017 Elsevier Ltd
Guest T.B.,Dalhousie University |
Hay A.E.,Dalhousie University
Journal of Geophysical Research: Oceans | Year: 2017
The vertical structure of surface gravity wave-induced pore pressure is investigated within the intertidal zone of a natural, steeply sloping, megatidal, mixed sand-gravel-cobble beach. Results from a coherent vertical array of buried pore pressure sensors are presented in terms of signal phase lag and attenuation as functions of oscillatory forcing frequency and burial depth. Comparison of the observations with the predictions of a theoretical poro-elastic bed response model indicates that the large observed phase lags and attenuation are attributable to interstitial trapped air. In addition to the dependence on entrapped air volume, the pore pressure phase and attenuation are shown to be sensitive to the hydraulic conductivity of the sediment, to the changing mean water depth during the tidal cycle, and to the redistribution/rearrangement of beach face material by energetic wave action during storm events. The latter result indicates that the effects on pore pressure of sediment column disturbance during instrument burial can persist for days to weeks, depending upon wave forcing conditions. Taken together, these results raise serious questions as to the practicality of using pore pressure measurements to estimate the kinematic properties of surface gravity waves on steep, mixed sand-gravel beaches. © 2016. The Authors.
Monfared Y.E.,Dalhousie University |
Ponomarenko S.A.,Dalhousie University
Optics Express | Year: 2017
We explore theoretically and numerically optical rogue wave formation in stimulated Raman scattering inside a hydrogen filled hollow core photonic crystal fiber. We assume a weak noisy Stokes pulse input and explicitly construct the input Stokes pulse ensemble using the coherent mode representation of optical coherence theory, thereby providing a link between optical coherence and rogue wave theories. We show that the Stokes pulse peak power probability distribution function (PDF) acquires a long tail in the limit of nearly incoherent input Stokes pulses. We demonstrate a clear link between the PDF tail magnitude and the source coherence time. Thus, the latter can serve as a convenient parameter to control the former. We explain our findings qualitatively using the concepts of statistical granularity and global degree of coherence. © 2017 Optical Society of America.
Zheng L.,Dalhousie University |
Li J.,Dalhousie University |
Obrovac M.N.,Dalhousie University
Chemistry of Materials | Year: 2017
Sodium ion batteries have garnered significant research attention in recent years due to the rising demand for large-scale energy storage solutions as well as the high abundance of sodium. P2-type layered oxide materials have been identified as promising positive electrode materials for sodium ion batteries. Previously, P2-Na2/3Ni1/3Mn2/3O2 was shown to have a high operating voltage and high capacity but suffers from a step-like voltage curve and capacity loss during cycling, potentially due to its P2-O2 transition at high voltages. One strategy to improve cycling performance has been to dope Ni2+ with other 2+ cations, such as Zn2+ or Mg2+, which improved capacity retention but significantly decreases reversible capacity, since these ions were not electrochemically active. Since Cu2+ has been shown to be electrochemically active, we replaced Ni2+ with Cu2+, resulting in air-stable Na2/3Ni1/3-xCuxMn2/3O2 (0 ≤ x ≤ 1/3). Both Ni2+/Ni4+ and Cu2+/Cu3+ participate in the redox reaction during cycling, capacity retention was greatly improved, and phase changes were suppressed during cycling without sacrificing much capacity. The material retains a P2/OP4 structure even when cycled to high voltages. The doping strategy is a promising approach for the future development of positive electrode materials for sodium ion batteries. © 2017 American Chemical Society.
Kachuk C.,Dalhousie University |
Doucette A.A.,Dalhousie University
Journal of Proteomics | Year: 2017
Top-down proteomics (TDP) has great potential for high throughput proteoform characterization. With significant advances in mass spectrometry (MS) instrumentation permitting tandem MS of large intact proteins, a limitation to the widespread adoption of TDP still resides on front-end sample preparation protocols (e.g. fractionation, purification) that are amenable to MS analysis of intact proteins. Chromatographic strategies are improving but pose higher risk of sample loss. Gel-based separations (e.g. GELFrEE) may alleviate this concern but at the expense of requiring sodium dodecyl sulfate (SDS). While this surfactant maintains protein solubility during fractionation, the advantage is short-lived, as the detergent must ultimately be depleted to avoid MS signal suppression. To do so requires overcoming strong interactions between SDS and protein. Adding to the challenge, one must now consider upholding the solubility of purified protein(s) in the absence of SDS. This review explores uses of SDS in TDP workflows, addressing front-end strategies that reduce matrix interferences while maximizing recovery of intact proteins in MS-compatible formats. Significance: The benefits of employing SDS in a TPD workflow can easily outweigh the disadvantages. Several SDS depletion strategies are available, though not all are equally amenable to TDP. This review provides a comprehensive and critical accounting of SDS in TDP, demonstrating methods that are suited to MS analysis of intact proteins. © 2017.
Guo L.,Dalhousie University |
Sheng J.,Dalhousie University
Ocean Dynamics | Year: 2017
A numerical study is conducted to investigate the impact of climate changes on ocean surface gravity waves over the eastern Canadian shelf (ECS). The “business-as-usual” climate scenario known as Representative Concentration Pathway RCP8.5 is considered in this study. Changes in the ocean surface gravity waves over the study region for the period 1979–2100 are examined based on 3 hourly ocean waves simulated by the third-generation ocean wave model known as WAVEWATCHIII. The wave model is driven by surface winds and ice conditions produced by the Canadian Regional Climate Model (CanRCM4). The whole study period is divided into the present (1979–2008), near future (2021–2050) and far future (2071–2100) periods to quantify possible future changes of ocean waves over the ECS. In comparison with the present ocean wave conditions, the time-mean significant wave heights (Hs) are expected to increase over most of the ECS in the near future and decrease over this region in the far future period. The time-means of the annual 5% largest Hs are projected to increase over the ECS in both near and far future periods due mainly to the changes in surface winds. The future changes in the time-means of the annual 5% largest Hs and 10-m wind speeds are projected to be twice as strong as the changes in annual means. An analysis of inverse wave ages suggests that the occurrence of wind seas is projected to increase over the southern Labrador and central Newfoundland Shelves in the near future period, and occurrence of swells is projected to increase over other areas of the ECS in both the near and far future periods. © 2017 Springer-Verlag Berlin Heidelberg
Jannasch E.,Dalhousie University
Structures and Architecture - Proceedings of the 3rd International Conference on Structures and Architecture, ICSA 2016 | Year: 2016
Both parabola and catenary may be modeled as differentiable curves. However, the author and his students find that spreadsheets iterating simple arithmetic have their advantages. Incremental construction of spreadsheets enables robust, stepwise learning. The completed calculators display a rich array of properties that support detailed design. They also highlight similarities and differences between geometries. Design variation may be introduced parametrically, or at discrete points. Finally, rigorous minds appreciate that real masonry structures and tension arrays are composed of discrete elements, so the incremental model is often more accurate than a differentiable approximation. Students working with these spreadsheets develop the confidence and ability to tackle more complex problems, such as the funicular of a dome. This curve is not a Hookean catenary but reflects the non-uniform and non-trivial weighting of a Polenian lune. Simple tools needn’t limit us to simple subjects, they enable comprehension and design of sophisticated structures. © 2016 Taylor & Francis Group, London.
Bearne S.L.,Dalhousie University
Biochimica et Biophysica Acta - Proteins and Proteomics | Year: 2017
Background: Enzymes of the enolase superfamily (ENS) are mechanistically diverse, yet share a common partial reaction (abstraction of the α-proton from a carboxylate substrate). While the catalytic machinery responsible for the deprotonation reaction has been conserved, divergent evolution has led to numerous ENS members that catalyze different overall reactions. This rich functional diversity has made the ENS an excellent model system for developing the approaches necessary to validate enzyme function. However, enzymes of the ENS also share a common bidomain structure ((β/α)7β-barrel domain and α+β capping domain) which makes validation of function from structural information challenging. Scope of the review: This review presents a comparative survey of the structural data obtained over the past decade for enzymes from all seven subgroups that comprise the ENS. Major conclusions: Of the seven ENS subgroups (enolase, mandelate racemase (MR), muconate lactonizing enzyme, β-methylaspartate ammonia lyase, d-glucarate dehydratase, d-mannonate dehydratase (ManD), and galactarate dehydratase 2), only enzymes of the MR and ManD subgroups exhibit an additional feature of structural complexity-an interdigitating loop. This loop emanates from one protomer of a homodimeric pair and penetrates into the adjacent, symmetry-related protomer to either contribute a binding determinant to the active site of the adjacent protomer, or act as a 'flying buttress' to support residues of the active site. General significance: The analysis presented in this review suggests that the interdigitating loop is the only gross structural element that permits functional distinction between ENS subgroups at the tertiary level of protein structure. © 2017 Elsevier B.V.
Jannasch E.,Dalhousie University
Structures and Architecture - Proceedings of the 3rd International Conference on Structures and Architecture, ICSA 2016 | Year: 2016
A funicular masonry dome experiences no hoop stresses, whether tensile or compressive, so it is always on the verge of bursting. Shallow spheric domes maintain compressive stresses in each course and are therefore more stable than the "ideal" funicular form. Viable non-funicular domes also include Herrero’s flat vault at the Escorial, and Mackenzie’s 1840 concept of an inverted vault fan. The author and a team of students studied these forms through active structural models. They also built other forms in un-mortared, unreinforced, and frictionless masonry, including an "anti-dome" that descends from its abutments to a low center, and an "ambi-dome" that rises from a peripheral ring to a circular crown and then descends to a central, circular oculus. These counter-intuitive forms demonstrate compressive hoop actions and orthogonal shear resistances that are seldom discussed in structures texts. Exploring these capacities is instructive, exploiting them expands the formal limits of masonry construction. © 2016 Taylor & Francis Group, London.
Akbulut-Yuksel M.,Dalhousie University
Journal of Health Economics | Year: 2017
This paper estimates the causal long-term consequences of an exposure to war in utero and during childhood on the risk of obesity and the probability of having a chronic health condition in adulthood. Using the plausibly exogenous city-by-cohort variation in the intensity of WWII destruction as a unique quasi-experiment, I find that individuals who were exposed to WWII destruction during the prenatal and early postnatal periods have higher BMIs and are more likely to be obese as adults. I also find an elevated incidence of chronic health conditions such as stroke, hypertension, diabetes, and cardiovascular disorder in adulthood among these wartime children. © 2017 Elsevier B.V.
Weerasinghe S.D.S.,Dalhousie University
Epidemiology Biostatistics and Public Health | Year: 2017
Background: When fitting statistical models for complex health outcome data; zero inflation, autocorrelation, confounding, and seasonality play an important role in accurately assessing air pollution risk, especially when using such model estimates for national air quality health indices (NAQHI) formation. NAQHI generalizes model estimates across all geographies and seasons and neglects area and season specific variations. The aim here is to develop complex statistical models, specific to the data structures and to demonstrate effectiveness of these model estimates in public health message delivery using NAQHI. Methods: I fitted zero inflated, auto regressive, Poisson and Negative Binomial models with lagged effects for sparse asthma admissions and ambient air pollution data and compared the model risk estimates with that of the NAQHI. Data came from two sites, Halifax, an urban, traffic and industry polluted site and Sydney, a rural waste disposal polluted site, in the province of Nova Scotia, Canada. Data complexity structure was assessed by comparing the estimates with and without each structure. Results: NAQHI used three pollutants, Nitrogen Dioxide, Ozone and particulate matter. I found Carbon monoxide in the urban site and lead in the waste disposal site as prominent pollutants with significant seasonal differences. The findings demonstrated severe under-assessment of asthma admission relative risk by NAQHI, when auto correlation and zero inflation are ignored whereby prominent pollutant effects are omitted. Conclusion: This study demonstrated the importance of complex statistical model use and the consequences of not consideration of specific data structures in public health risk assessments. © 2017, Prex S.p.A. All rights reserved.
Romao R.L.P.,Dalhousie University |
Lorenzo A.J.,University of Toronto
Urology | Year: 2017
We report a case of vaginal rhabdomyosarcoma where vaginectomy with buccal mucosa vaginoplasty was performed to avoid radiation therapy to the young pelvis.The patient presented at 30 months with an exophytic vaginal mass, found to be botryoid rhabdomyosarcoma. After receiving neoadjuvant vincristine, actynomycin D, and cyclophosphamide chemotherapy with good response, she underwent surgery. It was performed using an anterior sagittal approach on the prone position, which allowed for a safe circumferential dissection of the vagina all the way to the cervix and en bloc resection. Two buccal mucosa grafts were used for vaginoplasty. Pathology revealed negative margins. The patient completed therapy in October 2014 and remains disease-free. © 2017 Elsevier Inc.
Petropanagos A.,Dalhousie University
Journal of Bioethical Inquiry | Year: 2017
Testicular tissue cryopreservation (TTCP) aims to preserve the future option of genetic reproduction for prepubescent cancer patients who are at risk of infertility as a result of their cancer therapies. This technology is experimental and currently only offered in the research context. As TTCP moves towards becoming more widely available, it is imperative that healthcare providers recognize the complex ethical issues surrounding this technology. This scoping review study identifies and assesses the range and depth of ethical concerns related to this testicular tissue cryopreservation technology. At present, no such scoping review of ethical concerns exists in the TTCP literature. The forty-three full-text articles included in this study yielded twenty-two different ethical considerations discussed in relation to TTCP. It was observed that these ethical considerations fit within a mainstream Principlism approach to bioethics. Accordingly, there are ethical gaps in the TTCP literature that can be identified with alternative moral lenses. In particular, it was found that ethical concerns related to context and relational aspects of identity were absent in nearly all ethical examinations of TTCP. Furthermore, only 9 per cent of articles reviewed in this study focused primarily on the ethics of TTCP, thus demonstrating a need for further in depth ethical analyses of this technology. The results of this study are important for supporting the ethical provision of TTCP and can contribute to policy and guideline development. The findings of this study demonstrate the need for greater depth and diversity in analyses of ethical considerations related to this technology. © 2017 Journal of Bioethical Inquiry Pty Ltd.
Neumann P.E.,Dalhousie University
Clinical Anatomy | Year: 2017
The definition of an organ is vague, so that listing and classifying human organs is problematic. The classical Greek definition of an organ as an instrumental part of the body has been supplemented in modern biology by stating that organs occupy a hierarchical level between systems and tissues. Not all anatomical entities on that level meet the requirement of a special function. Thus it appears that systems are composed of organs and connecting (or linking) structures, such as some connective tissues, various tubular entities, and nerves. Clin. Anat. 30:288–289, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.
News Article | April 24, 2017
Animals have evolved a wide variety of inventive lovemaking strategies, but some are easier for biologists to observe than others. Dolphins, for instance, have labyrinthine internal genitalia, so while there's plenty of footage of these marine mammals mating, the actual "copulatory fit" of the dolphin penis within the vagina is not well understood, according to biologist Dara Orbach, a postdoctoral fellow at Dalhousie University. "While it may seem intuitive that the penis fits well into the vagina during copulation, the biomechanics and details of the anatomical fit can be quite complex and have seldom been explored," said Orbach, in a statement. "Whales, dolphins and porpoises have unusual vaginal folds, spirals, and recesses that the penis and sperm must navigate through to successfully fertilize the egg." To untangle these mysteries of cetacean reproductive behavior, Orbach and her colleagues devised a way to study dolphin sex in the laboratory. She presented the team's findings on Sunday at the Experimental Biology 2017 conference, which runs from April 22 to 26 in Chicago. First, the team collected bottlenose dolphins that had died of natural causes, and removed their reproductive tracts. Then the real magic began, as the "flaccid" and "frozen-thawed" dolphin vaginas were stained with iodine and penetrated by penises that had been "mechanically inflated" and treated with formalin to "maintain rigidity," according to Orbach's presentation abstract. The disembodied sets of dolphin junk were scanned independently and the copulatory position with computer tomography. CT scan showing dolphin penis (red) inside folds of dolphin vagina. Image: Dara Orbach, Dalhousie UniversityWhat did we learn from this dolphin necromancy? One insight was that "the tip of the bottlenose dolphin penis navigates around the female's single vaginal fold to achieve successful insemination," according to the abstract. Orbach also said her team's simulated copulation methods could have implications for studying the reproductive dynamics of many animals, which could inform captive breeding programs. Read More: Why Some Animals Try Mating with the Wrong Species Basically, creating a map of the "anatomical landmarks" involved in copulation, to quote Orbach, gives breeders a better understanding of how to stimulate those regions during artificial insemination to enhance the probability of fertilization. By analyzing which unique penetration angles lead to conception, researchers can predict or recommend the best alignments for successful breeding. The secrets of dolphin fertilization are being unraveled by innovative simulated sex techniques in laboratories around the world. It's a weird day job, but our understanding of the unique evolutionary biology of marine mammals, our distant cousins, depends on it. Subscribe to Science Solved It , Motherboard's new show about the greatest mysteries that were solved by science.
News Article | April 26, 2017
« Toyota begins trial operation of hybrid power generation system: SOFCs plus micro turbines | Main | ABB to provide fast charging technology in UK for electric buses; opportunity charging » BASF and Argonne National Laboratory have reached a business resolution of their pending Li-ion battery patent disputes with Umicore. Umicore is now licensed to make, use, sell, offer to sell, distribute and import nickel-manganese-cobalt (NMC) cathode material for lithium-ion batteries in the United States under BASF’s and Argonne’s U.S. Patent Nos. 6,677,082; 6,680,143; 7,135,252; and 7,468,223. BASF and Argonne are dismissing their pending action in the United States District Court for the District of Delaware against Umicore. The parties are filing a petition for rescission of the existing limited exclusion order with the International Trade Commission (ITC). Patents on NMC reach back into the 2000s, with Argonne National Laboratory filing the first one in 2000 based on work done by Dr. Michael Thackeray, followed shortly thereafter by a patent filed by 3M based on work done by Dr. Jeff Dahn at Dalhousie University. BASF acquired licenses to the Argonne patents in 2009. (Earlier post.) In 2015, BASF and Argonne National Laboratory sued Umicore for what they said was infringement of the Argonne patents for nickel-cobalt-manganese (NCM) cathode raw materials.
News Article | April 20, 2017
Weed dispensaries have popped up in many major cities like goose shit in the springtime, and an oddly stressful ritual has entered many of our lives: choosing a strain of the devil's lettuce to roll into a jazz cigarette. The conversation typically goes something like this: Dispensary lady: My guy, today we've got some Jack Herer, which is sativa-dominant and has a cerebral and talkative high, or Banana Clip, which is close to a 50/50 hybrid and will give you the body buzz of an indica with some of the effects of a sativa. We've also got God's Green Crack and Mango Dream. Me, internally: Hm, seems fake. Me, externally: Banana Clip, please. After sampling the bud (this actually happened), the hybrid Banana Clip felt suspiciously similar to a strain I'd previously tried, which was supposedly an "almost pure" strain of another variety. I also couldn't find any trace of a strain called Banana Clip on the web, and I suspect I was smoking AK Banana. Just what the hell was going on inside this disorienting kaleidoscope of primo greens, I wondered? Is any of this even, well, real? Unfortunately, scientifically speaking, weed strains are mostly bullshit. But let's back up for a second. For the uninitiated, a "strain" of marijuana is generally understood to be a unique genetic blend—a hybrid—of the two (supposedly) main types of weed, sativa and indica, with some additional tweaks. They all promise different physical effects. The time-tested rule of thumb for stoners, though, is that sativas have a more cerebral and wakeful high, while indicas are good for zoning out on your couch for hours and watching Planet Earth. I informally polled a handful of coworkers and their friends, and most believed that the general differences between sativa and indica-dominant strains are real. Some said they keep coming back to a particular strain, like Jack Herer. One person who asked to go by "Doug" said they prefer "pure" sativa strains. Notably, most folks said that before dispensaries moved in, they didn't really care about which variety of weed they smoked—pot was pot. This might be because, when it comes to the genetic differences between a strain of weed that's supposedly 30 percent indica and 70 percent sativa, or vice-versa, science has already strongly suggested that it's a big lie. A 2015 study by Canadian scientists looked at 81 marijuana strains and found that the reported sativa-indica split rarely matched their actual genetic makeup. "It's crazy, it's absolutely nuts. I mean, you couldn't run an industry like this anywhere else, except for cannabis" "They call things Purple Kush, but Purple Kush does not mean anything," said Sean Myles, a professor of agricultural genetic diversity at Dalhousie University and co-author of the 2015 study, over the phone. "There are so many exceptions, and the correlation is so weak, that putting a number on a bag and saying, 'This is a 50/50 hybrid of indica and sativa,' is highly, highly dubious." Most folks probably think strains are genetically similar if they have a similar name, but this too can be misleading. For example, "haze" varieties of weed are expected to be more sativa-dominant. But, according to the 2015 study, while Super Silver Haze and Neville's Haze are reported as being sativa-dominant and deliver, others, like Domina Haze, are actually more genetically similar to indica-dominant "kush" strains, like Master Kush or King's Kush. A full 35 percent of strains the researchers tested had more genetic similarities to differently-named varieties than to similarly-named ones. "When you go into a grocery store and there's a big pile of apples labelled as Honeycrisp, you expect that they're actually Honeycrisp apples." Myles said. "You can't just throw McIntosh apples in there and sell them for $4.99 a bag." "It's crazy, it's absolutely nuts," he continued. "I mean, you couldn't run an industry like this anywhere else, except for cannabis." So names don't mean much. Fine. But the holy dichotomy of sativa and indica—I mean, that exists, right? There are sativa strains and indica strains, and they affect us differently, even if they're frequently mislabeled? "We don't really know if indica or sativa exist in their purest forms," said Myles. "In terms of what botanists have described in nature, we can't get ahold of samples where we can be 100 percent confident that its a sativa or indica. This plant has been shuffled through so many human hands over so many millennia." We may loosely call things "indica" or "sativa," Myles continued, and that's a fair rule of thumb for describing their physical traits and psychoactive effects. But since nobody was keeping track of marijuana with the methods of a modern agriculturist some 5,000 years ago, we don't know what a "pure" sativa or indica really is, DNA-wise, he said. Who's to say what the defining characteristics of a pure sativa or indica really are? So, "pure" sativa or indica strains are also probably fictions. Still, the scientific literature suggests that plants with more sativa ancestry have higher levels of tetrahydrocannabinol, or THC, than indica-dominant plants, which have higher levels of cannabidiol, or CBD. As for what these compounds do, many studies have shown basically the same thing: THC gets you high, and CBD does not. It's not totally clear what CBD does to the brain, but a 2008 study showed that, in high doses, CBD and THC can work together, with CBD alleviating some of the anxiety reported after THC ingestion. "One day you'll be able to go to a dispensary and get Lemon Skunk, and be sure that it's Lemon Skunk" According to Myles, it's better to think of weed as existing on a spectrum of sativa-ness and indica-ness, and the most accurate way to describe weed is its THC and CBD content rather than its genetic heritage. This is how government-approved medicinal grow-ops do business. Bedrocan, for example, doesn't name its pot after strains you find on the street. For example, instead of telling someone they're about to smoke Purple Kush, it's better to say they're about to smoke "Bedrobinol," one of Bedrocan's trademarked products, which has a standardized THC content of 13.5 percent and less than 1 percent CBD. It's less fun, but at least you know what you're getting. Going forward, knowing what a strain of weed actually means, and will do to you, will require rigorous genetic indexing, and standardizing the creation of new strains. Myles hopes that marijuana becoming more acceptable (and legal, at least in some places) will help with this. "As we legitimize the use of cannabis, the science necessarily catches up—it's not going to stay in the dark forever," he said. "One day you'll be able to go to a dispensary and get Lemon Skunk, and be sure that it's Lemon Skunk." Or Banana Clip. Here's to the future. Subscribe to Science Solved It , Motherboard's new show about the greatest mysteries that were solved by science.
News Article | April 21, 2017
Whales and dolphins have surprisingly interesting sex lives, replete with various positions, elaborate vaginas, and a rare type of penis that’s always mostly erect. Dara Orbach, a marine mammologist at Dalhousie University in Halifax, Canada, has been studying these elaborate cetacean hookups for 7 years—and she’s made some shocking discoveries, some of which she’ll be presenting today at the Experimental Biology 2017 meeting. Science sat down with Orbach to chat about her work—and the best part about studying the sex habits of some of the ocean’s most famous creatures. This interview has been edited for clarity and length. Q: Let’s start with the most obvious question: Why study this? A: Copulation is the most direct possible interaction between males and females, but we know so little about it largely due to the physical challenges of studying it, especially with underwater creatures. So it’s only by looking internally at the animals while they’re copulating that we can understand more about these mechanisms. We do this by looking at tissue samples from animals that died of natural causes. We use whole penises and whole vaginas. Q: And then you go into the lab and put them together like puzzle pieces? A: Yeah. But what makes our study more unique is that Diane Kelly, one of my co-authors, found a way to inflate these penises to their full erect size, which hasn’t been done before. If you think about a specimen that is postmortem, it’s going to start to shrivel up. We found a way to inflate them so they would be the most close mimic of what a real intromission would look like. Q: How does one inflate a dead dolphin’s penis? A: We used pressurized saline, so essentially we had a nitrogen tank and we filtered the air under pressure into a smaller keg—like a beer keg—which was full of saline, and then pumped that into the penis. Q: What are female genitals like to work with? A: They’re amazing just because of this diversity, which has never been documented before. You open them up and you’re not really ever sure what you’re going to see inside. Is it going to be relatively simple? Or will there be these spirals? Or will there be deep folds? Or shallow ones? Opening up each reproductive tract is unique, and you never know what you’re going to see with a new species. Q: In the wild, how do dolphins copulate? A: It’s very variable. Some species, like dusky dolphins, copulate belly to belly. Bottle nose dolphins seem to make a T-formation, where the male crosses the female exactly at her midline. Harbor porpoises are really unique in that they wait for the female to come to the surface of the water to take a breath and then they leap out of the water and try to hook her with their penises. Q: Could it be that some of the positions are just for fun? A: This is what the whole purpose of the research is to understand. They have sex all year round even when they can only conceive for certain periods of the year. By looking at how the genitals align, we can now say certain body positions are more likely to lead to successful fertilization than others, which might be for purposes other than reproducing. Is it play? Is it working out hierarchies? Is it establishing dominance? Is it learning? There could be many functions of sex. Q: What is the best and worst thing about this line of research? A: I think the best thing is how exciting it is. I’ve never told anyone what I’ve done, and they’ve been bored with listening to me talk about it. Also, it was so faux pas to study sex and sexual behavior and genitalia for a long time that it really is an understudied field and there’s this huge opening in terms of new research directions. It seems like the sky is the limit. The worst part? I don’t know if there is a worst part. I really, really love my job.
News Article | May 4, 2017
TORONTO, May 04, 2017 (GLOBE NEWSWIRE) -- Regardless of where a baby is born in Canada, they should have access to the same resources and help, if needed. At the moment, infant hearing and screening programs vary widely across the country. May is Speech and Hearing Awareness Month, and The Hearing Foundation of Canada (THFC) is launching a new national campaign: www.TinyEARS.ca. The campaign is calling on the Canadian government to create a national strategy for infant hearing screening and intervention. So that no child is left behind. TinyEARS.ca will unite Canadian voices on behalf of babies, in the belief that every child in Canada has a right to an equal chance at reaching their full potential. “Imagine that you can't hear your mother's voice, and you have no way of telling her. Hearing loss in babies is invisible, but if detected and addressed early, we give babies the best chance for success. We need to do this right across the country. This program already exists in the United States and other countries. Canada is falling behind.” - Steven J. Aiken, PhD, Associate Professor, School of Human Communication Disorders Departments of Surgery and Psychology & Neuroscience, Dalhousie University The Canadian government needs to demonstrate national leadership and take infant hearing seriously. TinyEARS.ca calls for children to have: For parents to have: And for Canadians to: The campaign involves a hard-copy petition, available for signature by contacting THFC, and a supporting online petition, available at TinyEARS.ca. This petition will be formally presented to the House of Commons at the earliest possible date. About The Hearing Foundation of Canada The Hearing Foundation of Canada is a national charitable organization committed to improving hearing health by fostering safe listening habits and hearing loss detection from an early age, raising awareness about the consequences of hearing loss, and supporting medical research that improves diagnosis and treatment.
News Article | May 4, 2017
New Rochelle, NY, May 4, 2017--Suicidal thoughts and attempts by adult transgender individuals were 14 and 22 times higher, respectively, than rates for the general public, according to a new study published in Transgender Health, a peer-reviewed open access journal from Mary Ann Liebert, Inc., publishers. The article is available open access on the Transgender Health website. In a meta-synthesis of the transgender suicidality literature that included 42 studies published over 19 years, coauthors Noah Adams, Dalhousie University, Halifax, Maaya Hitomi, University of Saskatchewan, Saskatoon, and Cherie Moody, McGill University, Montreal, Canada, reported differences in the rates of suicidal ideation and suicide attempts between male-to-female and female-to-male transgender respondents and gender non-conforming individuals. Their findings, presented in the article "Varied Reports of Adult Transgender Suicidality: Synthesizing and Describing the Peer Reviewed and Grey Literature," can help target interventions aimed at suicide protection and support for these at-risk populations. "Suicidality and other forms of mental health distress are health disparities that increasingly are being documented and studied in the academic literature as disproportionately affecting transgender people and populations," says Editor-in-Chief Robert Garofalo MD, MPH, Professor of Pediatrics and Preventive Medicine, Northwestern University Feinberg School of Medicine, and Director, Center for Gender, Sexuality and HIV Prevention, Ann & Robert H. Lurie Children's Hospital of Chicago. "With this work, Noah Adams and colleagues advance the field by conducting a meta-analysis giving important epidemiologic data that can then be used to develop interventions designed to help transgender people who are having suicidal thoughts or are experiencing psychological distress." Transgender Health is the first peer-reviewed, open access journal dedicated to addressing the healthcare needs of transgender individuals throughout the lifespan and identifying gaps in knowledge as well as priority areas where policy development and research are needed to achieve healthcare equity. Led by Robert Garofalo, MD, MPH, Northwestern University Feinberg School of Medicine and Ann & Robert H. Lurie Children's Hospital of Chicago, the Journal provides critical coverage of topics including disparities in treatment and barriers to care, health services, cultural competency, mental health and well-being, and hormone therapy and surgery. For complete information and to access the Journal content, visit the Transgender Health website. (http://www. ) Mary Ann Liebert, Inc., publishers is a privately held, fully integrated media company known for establishing authoritative peer-reviewed journals in many promising areas of science and biomedical research, including LGBT Health, Health Equity, AIDS Patient Care and STDs, Journal of Women's Health, and Population Health Management. Its biotechnology trade magazine, GEN (Genetic Engineering & Biotechnology News), was the first in its field and is today the industry's most widely read publication worldwide. A complete list of the firm's 80 journals, books, and newsmagazines is available on the Mary Ann Liebert, Inc., publishers website. (http://www. )
News Article | May 4, 2017
The Canadian Food Inspection Agency (CFIA) has approved the use of mechanically-extracted camelina oil as a feed ingredient for farmed salmon and trout. Camelina sativa, or false flax, is a hardy oilseed plant that is rich in omega-3 fatty acids, protein and antioxidants. This super-nutritious plant is used as a vegetable oil for human consumption and as an ingredient or supplement in some animal feeds. Fish feed manufacturers have also explored the use of crop-based oilseeds like camelina as viable and cost-efficient substitutes for wild-sourced fish oils and proteins currently used in fish feeds. A recently completed large-scale study of camelina oil managed by Genome Atlantic with support from the Atlantic Canada Opportunities Agency (ACOA)’s Atlantic Innovation Fund, found camelina to be an excellent match to the fatty acid composition required in the diets of farmed fish. Backed by this compelling evidence, Genome Atlantic applied to the CFIA for approval of camelina oil for use in fish feeds. “Genome Atlantic and its partners have transformed a tiny seed into a big opportunity, creating an innovative, alternative solution with long-term benefits to industry,” said the Honourable Navdeep Bains, Minister of Innovation, Science and Economic Development and Minister responsible for ACOA. Aquaculture scientist Dr Chris Parrish of Memorial University, one of the study’s principal researchers, says that camelina oil has characteristics that make it a particularly promising alternative in fish diets. “Among the oils that can be used to replace fish oil in aquafeeds, camelina is one of the few with high levels of omega-3 fatty acids. While these omega-3 fatty acids are different to those present in fish oils, they enhance the ability of fish to synthesize the healthful long-chain omega-3 fatty acids that are needed for their optimal growth. This, in turn, ensures a healthful fillet for human consumers,” said Dr Parrish. Another of the study’s principal researchers, Dr Claude Caldwell of Dalhousie University, explains that the scientists found camelina oil to be sufficiently nutritious to replace all the fish oil in feeds, as well as some of the ground fish meal. “The use of wild-sourced fish to feed the farmed fish is not sustainable either ecologically or economically. Camelina could be a viable alternative,” he said. Considering that aquaculture companies spend 50 to 70 percent of their budgets on feed, finding a high-quality, lower cost source of oil could mean significant savings. While the CFIA’s recent approval only covers camelina oil, Dr Caldwell and his Dalhousie team are currently conducting feeding trials for the CFIA on camelina meal. “Camelina meal can’t entirely replace fish meal used in fish feeds, but it could replace some of that meal,” he said. Scientists at Rothamsted Research in the UK, who have succeeded in producing a genetically modified (GM) strain of camelina that contains high levels of the long chain omega-3s EPA and DHA believe it could – in the long run – help to pave the way for the use of GM camelina in fish feeds. As Professor Johnathan Napier, who leads the GM camelina research, told The Fish Site: “From our perspective, I believe that it is a positive step forward that conventional, unmodified camelina oil is approved for use as a salmon feed ingredient, though of course that particular oil will lack the critical long chain omega-3s EPA and DHA which we have engineered into our GM camelina. Anything that increases the visibility of camelina in general, either to farmers or to the aquafeed industry, is a positive step forward. It is interesting to note that the same academic consortium is interested in getting approval for inclusion of camelina seed meal in salmon diets, and this would also be something we would be pleased to see.” Camelina is grown in many parts of the world, including North America. Dr Caldwell suggests camelina could be a good rotation crop for potatoes, making it a potentially viable option for farmers in Maritime Canada. “There are about 200,000 acres of potatoes planted in this region. Camelina could be a successful rotation crop that could open new markets for farmers while making the aquaculture industry healthier and more sustainable,” said Dr Caldwell. The Camelina Project also received support from The Research and Development Corporation of Newfoundland and Labrador (RDC), the provinces of Nova Scotia and New Brunswick, the University of Saskatchewan, Memorial University, Dalhousie University, Agriculture and Agri-Food Canada, Minas Seeds, Cooke Aquaculture, and Genome Prairie.
News Article | April 17, 2017
It may not be the most appetizing way to extend life, but researchers have shown for the first time that older fish live longer after they consumed microbes from the poo of younger fish. The findings were posted to the bioRxiv.org preprint server on 27 March1 by Dario Valenzano, a geneticist at the Max Planck Institute for Biology of Ageing in Cologne, Germany, and his colleagues. So-called ‘young blood’ experiments that join the circulatory systems of two rats — one young and the other old — have found that factors coursing through the veins of young rodents can improve the health and longevity of older animals. But the new first-of-its-kind study examined the effects of 'transplanting' gut microbiomes on longevity. “The paper is quite stunning. It’s very well done,” says Heinrich Jasper, a developmental biologist and geneticist at the Buck Institute for Research on Aging in Novato, California, who anticipates that scientists will test whether such microbiome transplants can extend lifespan in other animals. Life is fleeting for killifish, one of the shortest-lived vertebrates on Earth: the fish hits sexual maturity at three weeks old and dies within a few months. The turquoise killifish (Nothobranchius furzeri) that Valenzano and his colleagues studied in the lab inhabits ephemeral ponds that form during rainy seasons in Mozambique and Zimbabwe. Previous studies have hinted at a link between the microbiome and ageing in a range of animals. As they age, humans2 and mice3 tend to lose some of the diversity in their microbiomes, developing a more uniform community of gut microbes, with once-rare and pathogenic species rising to dominance in older individuals4. The same pattern holds true in killifish, whose gut microbiomes at a young age are nearly as diverse as those of mice and humans, says Valenzano. “You can really tell whether a fish is young or old based on its gut microbiota.” To test whether the changes in the microbiome had a role in ageing, Valenzano’s team ‘transplanted’ the gut microbes from 6-week-old killifish into middle-aged 9.5-week-old fish. They first treated the middle-aged fish with antibiotics to clear out their gut flora, then placed them in a sterile aquarium containing the gut contents of young fish for 12 hours. Killifish don’t usually eat faeces, Valenzano notes, but they would probe and bite at the gut contents to see whether it was food, ingesting microbes in the process. The transplanted microbes successfully recolonized the guts of the fish that received them, the team found. At 16 weeks of age, the gut microbiomes of middle-aged fish that received 'young microbes' still resembled those of 6-week-old fish. The young microbiome ‘transplant’ also had dramatic effects on the longevity of fish that got them: their median lifespans were 41% longer than fish exposed to microbes from middle-aged animals, and 37% longer than fish that received no treatment (antibiotics alone also lengthened lifespan, but to a lesser extent). And at 16 weeks — old age, by killifish standards — the individuals that received young gut microbes darted around their tanks more frequently than other elderly fish, with activity levels more like 6-week-old fish. By contrast, gut microbes from older fish had no effect on the lifespans of younger fish, Valenzano and his team report. Exactly how microbes influence lifespan is hazy, Valenzano says. One possibility is that immune systems wear out with age, allowing harmful microbes to out-compete more beneficial bacteria. A microbiome transplant might, then, reset a middle-aged fish’s microbiome. Components of a more youthful microbiome could also promote longevity by somehow influencing the functioning of the immune system itself, Valenzano adds. “The challenge with all of these experiments is going to be to dissect the mechanism,” says Jasper. “I expect it will be very complex.” His laboratory is attempting microbiome swaps in differently aged fruit flies to test the impact on lifespan. Robert Beiko, a bioinformatician who studies microbial communities at Dalhousie University in Halifax, Canada, hopes to get funding to see whether microbiome swaps influence ageing in mice, too. He also wonders whether an individual’s own microbiome, sampled and preserved early in life, can extend its lifespan when reintroduced later. In humans, faecal transplants can help to treat some recurring infections, but Valenzano says it is far too early to consider the procedure for life extension. “I wouldn’t go that far. This is really early evidence that this has a potential positive effect.”
Yu Y.,National University of Singapore |
Luo Z.,National University of Singapore |
Chevrier D.M.,Dalhousie University |
Leong D.T.,National University of Singapore |
And 3 more authors.
Journal of the American Chemical Society | Year: 2014
The luminescence property of thiolated gold nanoclusters (Au NCs) is thought to involve the Au(I)-thiolate motifs on the NC surface; however, this hypothesis remains largely unexplored because of the lack of precise molecular composition and structural information of highly luminescent Au NCs. Here we report a new red-emitting thiolated Au NC, which has a precise molecular formula of Au22(SR)18 and exhibits intense luminescence. Interestingly, this new Au22(SR)18 species shows distinctively different absorption and emission features from the previously reported Au22(SR)16, Au22(SR)17, and Au25(SR)18. In stark contrast, Au22(SR) 18 luminesces intensely at ∼665 nm with a high quantum yield of ∼8%, while the other three Au NCs show very weak luminescence. Our results indicate that the luminescence of Au22(SR)18 originates from the long Au(I)-thiolate motifs on the NC surface via the aggregation-induced emission pathway. Structure prediction by density functional theory suggests that Au22(SR)18 has two RS-[Au-SR] 3 and two RS-[Au-SR]4 motifs, interlocked and capping on a prolate Au8 core. This predicted structure is further verified experimentally by Au L3-edge X-ray absorption fine structure analysis. © 2014 American Chemical Society.
Uher R.,Dalhousie University |
Uher R.,King's College London |
Pavlova B.,Dalhousie University |
Perlis R.H.,Massachusetts General Hospital
Depression and Anxiety | Year: 2014
The changes in diagnostic criteria for major depressive disorder (MDD) from the fourth to the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM) may appear small but have important consequences for how the diagnosis is used. In DSM-5, MDD is part of the new "Depressive disorders" section, which is separate from "Bipolar disorders", marking a division in what had been known as "Mood disorders". A small wording change has expanded the core mood criterion to include hopelessness, potentially broadening the diagnosis. The replacement of an operationalized bereavement exclusion with a call for clinical judgment in distinguishing normal reactions to significant loss from a disorder in need of clinical attention makes the diagnosis less objective and complicates investigations of the relationship between adversity and depression. A new persistent depressive disorder category is intended to encompass both dysthymia and chronic depression, but its relationship to MDD is ambiguous with conflicting statements on whether the two diagnoses should be concurrent if both sets of criteria are fulfilled. Clarification is also needed on whether MDD can be concurrent with the new broad "other specified bipolar and related disorders". New specifiers of MDD "with anxious distress" and "with mixed features" allow characterization of additional symptoms. The specifier "with perinatal onset" expands on the DSM-IV "postnatal onset" to include onset during pregnancy. We review the changes in MDD definition, provide guidance on their implementation and discuss their implications for clinical practice and research. © 2013 Wiley Periodicals, Inc.
Papp K.,Probity Medical Research |
Cather J.C.,Modern Research Associates |
Rosoph L.,North Bay Dermatology Center |
Sofen H.,Dermatology Research Associates |
And 4 more authors.
The Lancet | Year: 2012
Background Apremilast, a small-molecule inhibitor of phosphodiesterase 4, works intracellularly to modulate proinflammatory and anti-inflammatory mediator production, and doses of 20 mg twice daily have shown efficacy in the treatment of moderate to severe plaque psoriasis in a 12-week phase 2 study. We assessed the clinical efficacy and safety of different doses of apremilast in the treatment of patients with moderate to severe plaque psoriasis. Methods In this phase 2b, multicentre, randomised, placebo-controlled, dose-ranging study, patients (aged =18 years) with moderate to severe psoriasis were randomly assigned (in a 1:1:1:1 ratio) to receive oral placebo or apremilast 10, 20, or 30 mg twice daily at 35 US and Canadian sites between Sept 24, 2008, and Oct 21, 2009. At week 16, patients in the placebo group were assigned apremilast 20 or 30 mg twice daily until week 24. Randomisation was generated with a permuted-block randomisation list via interactive voice response system. For the first 16 weeks, treatment assignment was concealed from both investigators and participants. During weeks 16-24, investigators and participants all knew that treatment was active, but the dose was concealed. The primary endpoint was the proportion of patients achieving at least 75% reduction from baseline psoriasis area and severity index (PASI-75) at week 16. Analyses were by intention to treat; missing values were imputed by last-observation-carried-forward. This trial is registered with ClinicalTrials.gov, number NCT00773734. Findings 89 patients were randomly assigned apremilast 10 mg, 87 apremilast 20 mg, and 88 apremilast 30 mg twice daily; 88 were assigned placebo. At week 16, PASI-75 was achieved in five patients (6%) assigned placebo, ten (11%) assigned apremilast 10 mg, 25 (29%) assigned 20 mg, and 36 (41%) assigned 30 mg. Apremilast 10 mg did not differ significantly from placebo in achievement of the endpoint (odds ratio 2.10; 95% CI 0.69-6.42); for both apremilast 20 mg (6.69; 2.43-18.5; p<0.0001) and apremilast 30 mg (11.5; 4.24-31.2; p<0.0001), the differences from placebo were significant. Most adverse events (96%) were mild or moderate; at least 5% of patients had nausea, upper respiratory tract infection, diarrhoea, nasopharyngitis, headache, arthralgia (placebo), gastroenteritis, or dyspepsia. Eight serious adverse events occurred (three each, placebo and apremilast 20 mg; two, apremilast 30 mg); none were judged to be related to apremilast. Apremilast had no apparent effect on the results of haematological, urinalysis, immunological or inflammation, serum chemistry, or electrocardiographic tests. Interpretation Apremilast, given orally at 20 or 30 mg twice daily, seems to be efficacious, safe, and tolerable for patients with moderate to severe plaque psoriasis. Our results support continuing, longer-term studies. Funding Celgene Corporation.
Morsi W.G.,University of Ontario Institute of Technology |
El-Hawary M.E.,Dalhousie University
Electric Power Systems Research | Year: 2011
High power quality level is required in smart grids especially for non-stationary situations due to increased use of nonlinear loads and PQ disturbances such as dips, swells, transients and interruptions. Many power quality indices (PQIs) are available. In this paper a new fuzzy-wavelet packet transform-based power quality Index (FWPTPQI) is developed to amalgamate existing power quality indices as the output of a fuzzy based module based on fuzzy inference systems, knowledge base and existing PQI as input. Fuzzy systems allow handling the uncertainties associated with the electric power quality evaluation. The proposed approach has been applied to two case studies; stationary balanced and non-stationary unbalanced three-phase systems. The results are compatible with prevalent situations. The new index gives significant sense of the quality of transmitted electrical power. A comparative study of using different wavelet basis functions is considered and results indicate that Daubechies 10 and Daubechies 15 could be considered as the overall best wavelet basis functions. Since the new index represents an amalgamation of the PQ indices with less number of wavelet coefficients, it helps reduce the size of data processed which is required in smart grid applications. © 2011 Elsevier B.V. All rights reserved.
Hayden J.A.,Dalhousie University |
van der Windt D.A.,Keele University |
Cartwright J.L.,Dalhousie University |
Cote P.,University of Ontario Institute of Technology |
Bombardier C.,Toronto General Hospital
Annals of Internal Medicine | Year: 2013
Previous work has identified 6 important areas to consider when evaluating validity and bias in studies of prognostic factors: participation, attrition, prognostic factor measurement, confounding measurement and account, outcome measurement, and analysis and reporting. This article describes the Quality In Prognosis Studies tool, which includes questions related to these areas that can inform judgments of risk of bias in prognostic research. A working group comprising epidemiologists, statisticians, and clinicians developed the tool as they considered prognosis studies of low back pain. Forty-three groups reviewing studies addressing prognosis in other topic areas used the tool and provided feedback. Most reviewers (74%) reported that reaching consensus on judgments was easy. Median completion time per study was 20 minutes; interrater agreement (κ statistic) reported by 9 review teams varied from 0.56 to 0.82 (median, 0.75). Some reviewers reported challenges making judgments across prompting items, which were addressed by providing comprehensive guidance and examples. The refined Quality In Prognosis Studies tool may be useful to assess the risk of bias in studies of prognostic factors. © 2013 American College of Physicians.
Hutchings J.A.,Dalhousie University |
Hutchings J.A.,University of Oslo
ICES Journal of Marine Science | Year: 2014
The population dynamics of marine fish at low abundance has long been of interest. One century ago, Johan Hjort drew attention to the importance of understanding "the laws which govern the renewal of the animal population". Integral to the current work on the recovery of collapsed fish stocks is the association between abundance and per capita population growth rate (r), a negative correlation being representative of compensation and a positive correlation indicative of an Allee effect, also termed depensation. Allee effects are predicted to slow the rate, and increase the uncertainty, of recovery. Based on studies having sufficient data at low abundance, the magnitude of depletion experienced by some fish populations appears to have been sufficient to have generated either an Allee effect or a transition from strong to weak (or absent) compensatory dynamics. To a first approximation, empirically based Allee-effect reference points are consistent with suggested thresholds for overfishing and stock collapse. When evaluating Allee effects in marine fish, it is important not to conflate causal mechanism(s) with the pattern between r and abundance; the latter is of greater practical import. An additional caveat is that the longer a population remains at low abundance, the more likely it is that the environment around it will change in ways that are unfavourable to recovery. It might be this "temporal tyranny" of small population size that is most likely to produce an emergent Allee effect and depensatory dynamics in some collapsed marine fish populations. © 2014 International Council for the Exploration of the Sea. All rights reserved.
Minto C.,Dalhousie University |
Minto C.,Mayo Institute of Technology, Galway |
Worm B.,Dalhousie University
Ecology | Year: 2012
Species interactions that play out over large spatial scales are difficult to observe, particularly in the oceans. The current lack of empirical evidence for biologically meaningful interaction parameters likely delays the application of holistic management procedures. Here we estimate interactions during the early life history of fish across regions. We present separate and hierarchical Bayesian models that estimate the direction and strength of interactions between Atlantic cod and dominant pelagic fishes across much of their range in the North Atlantic. We test the hypothesis that small pelagic fish may reduce survival of cod at early life stages, and thereby contribute to the delayed recovery of depleted cod populations. Significant regional variation exists between cod recruitment and Atlantic herring abundance with eight of 14 regions displaying a negative relationship, four regions displaying no relationship, and a positive relationship observed in two regions. In contrast, most regions where Atlantic mackerel co-occurs showed no relationship with cod recruitment, with the possible exception of Gulf of St. Lawrence and Celtic Sea regions. Regions with sprat or capelin as dominant pelagics also displayed weak or no relationship, although the probability of a negative interaction with sprat increased when time series autocorrelation was accounted for. Overall, the interaction between herring and young cod was found to be negative with 94% probability, while the probability of negative interactions with mackerel was only 68%. Our findings suggest that the strength of predation or competition effects on young cod varies among small pelagic species but appears consistently for Atlantic herring; this effect may need to be considered in recovery trajectories for depleted cod populations. The methods introduced here are applicable in the investigation of species interactions from time series data collected across different study systems. © 2012 by the Ecological Society of America.
Chen Y.-T.,University of California at Davis |
Liu H.,Dalhousie University |
Stone S.,Dalhousie University |
Callis J.,University of California at Davis
Plant Journal | Year: 2013
The ABA Binding Factor/ABA-Responsive Element Binding Proteins (ABF/AREB) subfamily of bZIP-type transcription factors are positive effectors of ABA responses. Here, we examine the proteolytic regulation of two members: Arabidopsis thaliana ABF1 and ABF3. Both transcription factors are unstable in seedlings, and their degradation is sensitive to proteasome inhibition. ABA treatment of seedlings leads to their rapid accumulation, the result of slowed proteolysis. Deletion of the conserved C-terminal region required for 14-3-3 interaction destabilizes the proteins. The degradation of ABF1 and ABF3 are slower in vivo in seedlings lacking the ubiquitin E3 ligase KEEP ON GOING (KEG), and in vitro in extracts from keg seedlings, implicating KEG in their degradation. ABF1 and ABF3 are ubiquitylation substrates of KEG in vitro, and in vitro pull-down assays document their direct interaction. In contrast to ABI5, another KEG substrate, the degradation of ABFs and proteolytic regulation of ABFs by ABA still occurs in keg seedlings, suggesting that additional E3s participate in ABF1 and ABF3 proteolysis. Loss of ABF1 or ABF3 in the keg background has a phenotypic effect similar to the loss of ABI5, and there is no additional rescue of the keg phenotype in abf1 abf3 abi5 keg seedlings. This result suggests that the abundance of other substrates is altered in keg seedlings, affecting growth. In conclusion, ABF1 and ABF3 abundance is affected by ABA and KEG, and the conserved C4 region serves as a stabilizing element. © 2013 The Authors The Plant Journal © 2013 John Wiley & Sons Ltd.
Guedes R.N.C.,Federal University of Viçosa |
Cutler G.C.,Dalhousie University
Pest Management Science | Year: 2014
Ecological backlashes such as insecticide resistance, resurgence and secondary pest outbreaks are frequent problems associated with insecticide use against arthropod pest species. The last two have been particularly important in sparking interest in the phenomenon of insecticide-induced hormesis within entomology and acarology. Hormesis describes a biphasic dose-response relationship that is characterized by a reversal of response between low and high doses of a stressor (e.g. insecticides). Although the concept of insecticide-induced hormesis often does not receive sufficient attention, or has been subject to semantic confusion, it has been reported in many arthropod pest species and natural enemies, and has been linked to pest outbreaks and potential problems with insecticide resistance. The study of hormesis remains largely neglected in entomology and acarology. Here, we examined the concept of insecticide-induced hormesis in arthropods, its functional basis and potential fitness consequences, and its importance in arthropod pest management and other areas. © 2013 Society of Chemical Industry.
Chitnis S.S.,University of Victoria |
Carpenter Y.-Y.,Dalhousie University |
Burford N.,University of Victoria |
McDonald R.,University of Alberta |
Ferguson M.J.,University of Alberta
Angewandte Chemie - International Edition | Year: 2013
Square deal: Reactions of SbF3 with Me3SiOSO 2CF3 produce Sb3+ and [Sb-F]2+ cations, which form complexes with two or three Me3P ligands. Subsequent reductive elimination of diphosphonium or fluorophosphonium cations from the complexes give the folded square cyclo-[(Me3P) 4Sb4][OTf]4. Formation of the tetracation framework reveals new redox chemistry for Sb. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Ungar M.,Dalhousie University |
Ghazinour M.,Umea Sweden |
Richter J.,University of Rostock
Journal of Child Psychology and Psychiatry and Allied Disciplines | Year: 2013
Background: The development of Bronfenbrenner's bio-social-ecological systems model of human development parallels advances made to the theory of resilience that progressively moved from a more individual (micro) focus on traits to a multisystemic understanding of person-environment reciprocal processes. Methods: This review uses Bronfenbrenner's model and Ungar's social-ecological interpretation of four decades of research on resilience to discuss the results of a purposeful selection of studies of resilience that have been done in different contexts and cultures. Results: An ecological model of resilience can, and indeed has been shown to help researchers of resilience to conceptualize the child's social and physical ecologies, from caregivers to neighbourhoods, that account for both proximal and distal factors that predict successful development under adversity. Three principles emerged from this review that inform a bio-social-ecological interpretation of resilience: equifinality (there are many proximal processes that can lead to many different, but equally viable, expressions of human development associated with well-being); differential impact (the nature of the risks children face, their perceptions of the resources available to mitigate those risks and the quality of the resources that are accessible make proximal processes more or less influential to children's development); and contextual and cultural moderation (different contexts and cultures provide access to different processes associated with resilience as it is defined locally). Conclusion: As this review shows, using this multisystemic social-ecological theory of resilience can inform a deeper understanding of the processes that contribute to positive development under stress. It can also offer practitioners and policy makers a broader perspective on principles for the design and implementation of effective interventions. © 2012 The Authors. Journal of Child Psychology and Psychiatry © 2012 Association for Child and Adolescent Mental Health.
Kehoe S.,Dalhousie University |
Zhang X.F.,Cork Institute of Technology |
Boyd D.,Dalhousie University
Injury | Year: 2012
Several nerve guidance conduits (NGCs) and nerve protectant wraps are approved by the US Food and Drug Administration (FDA) for clinical use in peripheral nerve repair. These devices cover a wide range of natural and synthetic materials, which may or may not be resorbable. This review consolidates the data pertaining to all FDA approved materials into a single reference, which emphasizes material composition alongside pre-clinical and clinical safety and efficacy (where possible). This article also summarizes the key advantages and limitations for each material as noted in the literature (with respect to the indication considered). In this context, this review provides a comprehensive reference for clinicians which may facilitate optimal material/device selection for peripheral nerve repair. For materials scientists, this review highlights predicate devices and evaluation methodologies, offering an insight into current deficiencies associated with state-of-the-art materials and may help direct new technology developments and evaluation methodologies thereof. © 2010 Elsevier Ltd. All rights reserved.
Crozier L.G.,National Oceanic and Atmospheric Administration |
Hutchings J.A.,Dalhousie University |
Hutchings J.A.,University of Oslo
Evolutionary Applications | Year: 2014
The physical and ecological 'fingerprints' of anthropogenic climate change over the past century are now well documented in many environments and taxa. We reviewed the evidence for phenotypic responses to recent climate change in fish. Changes in the timing of migration and reproduction, age at maturity, age at juvenile migration, growth, survival and fecundity were associated primarily with changes in temperature. Although these traits can evolve rapidly, only two studies attributed phenotypic changes formally to evolutionary mechanisms. The correlation-based methods most frequently employed point largely to 'fine-grained' population responses to environmental variability (i.e. rapid phenotypic changes relative to generation time), consistent with plastic mechanisms. Ultimately, many species will likely adapt to long-term warming trends overlaid on natural climate oscillations. Considering the strong plasticity in all traits studied, we recommend development and expanded use of methods capable of detecting evolutionary change, such as the long term study of selection coefficients and temporal shifts in reaction norms, and increased attention to forecasting adaptive change in response to the synergistic interactions of the multiple selection pressures likely to be associated with climate change. © 2013 The Authors. Evolutionary Applications published by John Wiley & Sons Ltd.
Rollinson N.,Dalhousie University |
Hutchings J.A.,Dalhousie University |
Hutchings J.A.,University of Oslo
Ecology | Year: 2013
How parents divide the energy available for reproduction between size and number of offspring has a profound effect on parental reproductive success. Theory indicates that the relationship between offspring size and offspring fitness is of fundamental importance to the evolution of parental reproductive strategies: this relationship predicts the optimal division of resources between size and number of offspring, it describes the fitness consequences for parents that deviate from optimality, and its shape can predict the most viable type of investment strategy in a given environment (e.g., conservative vs. diversified bethedging). Many previous attempts to estimate this relationship and the corresponding value of optimal offspring size have been frustrated by a lack of integration between theory and empiricism. In the present study, we draw from C. Smith and S. Fretwell's classic model to explain how a sound estimate of the offspring size-fitness relationship can be derived with empirical data. We evaluate what measures of fitness can be used to model the offspring size- fitness curve and optimal size, as well as which statistical models should and should not be used to estimate offspring size-fitness relationships. To construct the fitness curve, we recommend that offspring fitness be measured as survival up to the age at which the instantaneous rate of offspring mortality becomes random with respect to initial investment. Parental fitness is then expressed in ecologically meaningful, theoretically defensible, and broadly comparable units: the number of offspring surviving to independence. Although logistic and asymptotic regression have been widely used to estimate offspring size-fitness relationships, the former provides relatively unreliable estimates of optimal size when offspring survival and sample sizes are low, and the latter is unreliable under all conditions. We recommend that the Weibull-1 model be used to estimate this curve because it provides modest improvements in prediction accuracy under experimentally relevant conditions. © 2013 by the Ecological Society of America.
Rollinson N.,Dalhousie University |
Hutchings J.A.,Dalhousie University |
Hutchings J.A.,University of Oslo
American Naturalist | Year: 2013
Parents can maximize their reproductive success by balancing the trade-off between investment per offspring and fecundity. According to theory, environmental quality influences the relationship between investment per offspring and offspring fitness, such that well-provisioned offspring fare better when environmental quality is lower. A major prediction of classic theory, then, is that optimal investment per offspring will increase as environmental quality decreases. To test this prediction, we release over 30,000 juvenile Atlantic salmon (Salmo salar) into eight wild stream environments, and we monitor subsequent growth and survival of juveniles.We estimate the shape of the relationship between investment per offspring (egg size) and offspring fitness in each stream. We find that optimal egg size is greater when the quality of the stream environment is lower (as estimated by a composite index of habitat quality). Across streams, the mean size of stream gravel and the mean amount of incident sunlight are the most important individual predictors of optimal egg size. Within streams, juveniles recaptured in stream subsections that featured larger gravels and greater levels of sunlight also grew relatively quickly, an association that complements our crossstream analyses. This study provides the first empirical verification that environmental quality alters the relationship between investment per offspring and offspring fitness, such that optimal investment per offspring increases as environmental quality decreases. © 2013 by The University of Chicago.
Brothers T.D.,Dalhousie University |
Rockwood K.,Dalhousie University |
Rockwood K.,Center for Healthcare of the Elderly
Current Opinion in HIV and AIDS | Year: 2014
PURPOSE OF REVIEW: Effective therapies have transformed HIV infection into a chronic disease, and new problems are arising related to aging. This article reviews the aging process, age-related deficit accumulation and frailty, and how these might be affected by chronic HIV infection. RECENT FINDINGS: Aging is characterized by acceleration in the rate of unrepaired physiologic damage an organism accumulates. HIV infection is associated with many factors that might affect the aging process, including extrinsic behavioral risk factors and co-infections, and multiple intrinsic factors, including intercellular communication, inflammation, and coagulation pathways. Whether each factor affects the aging process, they likely result in an increase in the risk of adverse health outcomes, and so give rise to frailty, likely with several clinical manifestations. SUMMARY: Age-related deficit accumulation is influenced by both the background or environmental rate of insults an organism sustains and the efficacy of intrinsic damage control and repair mechanisms. Both processes are likely affected in people living with HIV infection. © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins.
France R.L.,NSAC |
France R.L.,Dalhousie University
Freshwater Biology | Year: 2012
The energetic hypothesis proposes that the vertical structure of food webs should increase in height with increasing system productivity. I measured the trophic positions and extent of trophic separation between the invertebrate planktivores Mysis relicta and Chaoborus spp. and their putative zooplankton prey along a gradient of lake productivity with the use of stable nitrogen isotopes. In lakes of low productivity, these planktivores were found to be herbivorous, becoming omnivorous at intermediate lake productivities, and only able to be truly zooplanktivorous as lakes approached mesotrophy. A subsequent secondary analysis of literature data revealed that the strength of top-down trophic cascades among these organisms increased with lake productivity as reflected by relationships between the abundance of planktivores and that of phytoplankton. Increased omnivory under conditions of low productivity, effectively shortening the vertical structure of food webs as predicted by the energetic hypothesis, may produce increased community stability. © 2012 Blackwell Publishing Ltd.
Keith D.M.,Dalhousie University |
Hutchings J.A.,Dalhousie University |
Hutchings J.A.,University of Oslo
Canadian Journal of Fisheries and Aquatic Sciences | Year: 2012
The recovery of depleted species depends on their population dynamics at low abundance. Classical population growth models, applied widely in fisheries science, assume that per capita offspring production increases as abundance declines (compensation). However, slow or absent recovery by many depleted fishes might reflect unexpectedly weak compensation or the presence of Allee effects (depensation). Using meta-analytical techniques to describe reproductive dynamics, we find considerable variability among 207 exploited marine fish stocks (104 species) in how standardized per capita population growth changes with abundance. Although many species exhibit strong compensatory dynamics (negative density dependence), others show much weaker compensation than expected, and some exhibit evidence of an Allee effect, such as Atlantic cod (Gadus morhua) and Alaskan walleye pollock (Theragra chalcogramma). As data at low levels of abundance become increasingly available, it appears that compensation, while strong in some species, is comparatively weak or nonexistent in others, thus providing an explanation for why the recovery of some depleted stocks, despite reductions in exploitation, has been considerably less than what classic models of population growth would otherwise suggest.
Agency: European Commission | Branch: H2020 | Program: RIA | Phase: SFS-11a-2014 | Award Amount: 3.63M | Year: 2015
The AquaSpace project has the goal of providing increased space for aquaculture to allow increased production. Following the call, we will achieve this by identifying the key constraints experienced by aquaculture development in a wide range of contexts and aquaculture types, taking into account all relevant factors and advised by a Reference User Group. We will then map these constraints against a wide variety of tools/methods that have already been developed in national and EU projects for spatial planning purposes, including some that have been designed specifically for aquaculture. In the freshwater sector only, we will also consider ecosystem services provided by aquaculture that are relevant to integrated catchment planning and management. At 16 case study sites having a variety of scales, aquaculture at different trophic levels with different environmental interactions and most importantly with a range of key space-related development constraints as defined by local stakeholders, we will assess appropriate tools using a common process so as to facilitate synthesis and comparison. This case study approach will generate a large amount of information and is allocated about a third of the projects resources. The project will develop the outcomes leading to a set of evaluated tools for facilitating the aquaculture planning process by overcoming present constraints. This information will be presented on an interactive web-based platform with tailored entry points for specific user types (e.g. planners, farmers, public) to enable them to navigate to the tools most appropriate to their application. The knowledge and information gained during this process will be developed into an on-line module at Masters Level which will also be developed into a short CPD course aimed at aquaculture planning professionals. The public will be engaged by an innovative school video competition and a vehicle to ensure project legacy will be established.
Agency: European Commission | Branch: H2020 | Program: RIA | Phase: BG-08-2014 | Award Amount: 20.65M | Year: 2015
The overarching objective of AtlantOS is to achieve a transition from a loosely-coordinated set of existing ocean observing activities to a sustainable, efficient, and fit-for-purpose Integrated Atlantic Ocean Observing System (IAOOS), by defining requirements and systems design, improving the readiness of observing networks and data systems, and engaging stakeholders around the Atlantic; and leaving a legacy and strengthened contribution to the Global Ocean Observing System (GOOS) and the Global Earth Observation System of Systems (GEOSS). AtlantOS will fill existing in-situ observing system gaps and will ensure that data are readily accessible and useable. AtlantOS will demonstrate the utility of integrating in-situ and Earth observing satellite based observations towards informing a wide range of sectors using the Copernicus Marine Monitoring Services and the European Marine Observation and Data Network and connect them with similar activities around the Atlantic. AtlantOS will support activities to share, integrate and standardize in-situ observations, reduce the cost by network optimization and deployment of new technologies, and increase the competitiveness of European industries, and particularly of the small and medium enterprises of the marine sector. AtlantOS will promote innovation, documentation and exploitation of innovative observing systems. All AtlantOS work packages will strengthen the trans-Atlantic collaboration, through close interaction with partner institutions from Canada, United States, and the South Atlantic region. AtlantOS will develop a results-oriented dialogue with key stakeholders communities to enable a meaningful exchange between the products and services that IAOOS can deliver and the demands and needs of the stakeholder communities. Finally, AtlantOS will establish a structured dialogue with funding bodies, including the European Commission, USA, Canada and other countries to ensure sustainability and adequate growth of IAOOS.
News Article | May 18, 2016
Iron fertilization in the Pacific is not an effective solution to climate change, a new research has revealed. Experts believed that iron fertilization can cause sporadic growth of algae that absorbs carbon in the ocean. They said more iron means will result in higher algae productivity, thus, increasing the carbon dioxide absorbed from the atmosphere and sank to the sea floor. However, airborne dust irons in the Pacific did not translate to an increase in algae's ability to absorb carbon dioxide in the atmosphere, said Gisela Winckler, study lead author and a geochemist from Lamont-Doherty Earth Observatory (LDEO) in Columbia University. In fact, the study correlated that previous iron fertilization in the Pacific have resulted in lower production of algae. Even though iron fertilization conducted in the past have controversial outcomes, it does not suggest that the same findings will be applicable in other areas. Winckler is presently working with LDEO researcher and co-author Robert Anderson in studying iron dust fertilization and its effects on the Southern Ocean. In 2004, the European Iron Fertilization Experiment (EIFEX) in the Southern Ocean was successful in making algae captured carbon dioxide in their organic tissue. On the other hand, in 2009, German-Indian Lohafex experiment in the South Atlantic Ocean only resulted in minimal algal bloom, most of which were consumed by marine animals. This has resulted in carbon dioxide going into the food cycle, instead of sinking it. The Intergovernmental Panel on Climate Change (IPCC) included iron dusts in the climate change alleviation report (PDF), but also warned against its possible negative effects. The report stated that, while some areas may experience high productivity, downstream marine life may suffer due to low levels of nutrients. Other ill effects of iron dusts include deep ocean acidification, expansion of dead zones with minimal oxygen, but high nitrous oxide, which is more potent that carbon dioxide. The study also referenced the authors' earlier work, which tackled iron dust biological response in the Pacific about 20,000 years ago and expanded the study to include the algae growth from nearly half a million years ago. From there, they concluded that the productivity of the algae did not increase in the five glacial periods. Cores from deep sea sediments were gathered from three different areas in the equatorial Pacific. The researchers used these to test for barium to establish the level of organic matter that was brought to the ocean floor. The researchers also tested for opal that came from groups of algae. Thorium-232 measurements were also taken to identify the iron dust that came from land. The authors concluded that the purposeful addition of iron to the water surface of the Pacific will not result in a significant impact on mitigating the effects of atmospheric carbon dioxide. "While it is well recognized that atmospheric dust plays a significant role in the climate system by changing planetary albedo, the study by Winckler et al, convincingly shows that dust and its associated iron contents is not a key player in regulating the oceanic sequestration of CO2 in the equatorial Pacific on large spatial and temporal scales," said Stephanie Kienast, a marine geologist and paleoceanographer from Dalhousie University, and was not involved in the study. The study was published in the Proceedings of the National Academy of Sciences on May 16. © 2016 Tech Times, All rights reserved. Do not reproduce without permission.
News Article | February 15, 2017
TORONTO, ONTARIO--(Marketwired - Feb. 15, 2017) - Dundee Precious Metals Inc. (TSX:DPM) ("DPM" or "the Company") is pleased to announce the appointment of Ms. Juanita Montalvo to the board of directors of DPM. "We are delighted to welcome Juanita to the board and to the health, safety and environment committee of DPM," said Jonathan Goodman, Executive Chairman. "With decades of international experience in operations support, sustainability and risk management oversight, her diversity of skills and perspective will be a valuable addition to the Company." Ms. Montalvo brings to the DPM board 25 years of experience in developing and leading strategies to drive performance through excellence in corporate governance, partnership and joint venture management and good business practice. She is currently a Managing Partner with Acasta Cuba Capital, a leading advisory and investment firm dedicated to business opportunities in Cuba. Previously, she was a Senior Vice President at Sherritt International Corporation, a world leader in mining and refining of nickel from lateritic ores and Cuba's largest foreign investor - building and operating in mining, oil & gas, and power production. Ms. Montalvo served as Country Manager in Madagascar during the construction of the Ambatovy Joint Venture. From 2006 until 2014, Ms. Montalvo held a number of board positions with subsidiaries of Sherritt International Corporation and on Executive Committees to the board. She is also a director and Deputy Chairman of the board of Canada's National Ballet School. Ms. Montalvo holds a B.Sc. Biology and Biochemistry, a B.A. in International Development Studies and a Masters in Development Economics, all from Dalhousie University in Halifax, Nova Scotia. Ms. Montalvo also completed financial courses for executives at the Richard Ivey School of Management and the Canadian Securities course. Dundee Precious Metals Inc. is a Canadian based, international gold mining company engaged in the acquisition of mineral properties, exploration, development, mining and processing of precious metals. The Company's continuing operating assets include the Chelopech operation, which produces a copper concentrate containing gold and silver and a pyrite concentrate containing gold, located east of Sofia, Bulgaria; and the Tsumeb smelter, a complex copper concentrate processing facility located in Namibia. DPM also holds interests in a number of developing gold and exploration properties located in Bulgaria, Serbia, and northern Canada, including the Krumovgrad gold project currently under construction, which is expected to commence production in the fourth quarter of 2018, and its 10.7% interest in Sabina Gold & Silver Corp.
News Article | November 23, 2015
« Study finds substantial increase in nanoparticles in air as it crosses the Baltic Sea; shipping emissions responsible for about half | Main | Nemaska Lithium signs MOU with Johnson Matthey Battery Materials to collaborate on phase 1 plant » A team of researchers from the University of Maryland (UMD) and the US Army Research Laboratory (ARL) have devised a groundbreaking highly concentrated “Water-in-Salt” electrolyte that could provide power, efficiency and longevity comparable to today’s Lithium-ion batteries, but without the fire risk, poisonous chemicals and environmental hazards of current lithium batteries. A paper on their work is published in the journal Science. The researchers said their technology holds great promise, particularly in applications that involve large energies at kilowatt or megawatt levels, such as electric vehicles, or grid-storage devices for energy harvest systems, and in applications where battery safety and toxicity are primary concerns, such as safe, non-flammable batteries for airplanes, naval vessels or spaceships, and in medical devices like pacemakers. Lithium-ion (Li-ion) batteries power much of our digital and mobile lifestyle. However, their adoption in more strategically important applications such as vehicle electrification and grid storage has been slower, mainly because of concerns raised over their safety, cost, and environmental impact. Most of these concerns come from the nonaqueous electrolytes needed to withstand the high voltages (>3.0 V) of the chemistries, because the ester-based solvents are highly flammable and reactive with the charged electrodes, and the lithium salt (LiPF ) is thermally unstable and extremely toxic. Substantial costs are incurred not only directly by these electrolyte components but also to a larger degree by the stringent moisture-free process and safety management required for the dangerous combination of flammable electrolytes and energy-intensive electrodes. Aqueous electrolytes could resolve these concerns, but their electrochemical stability window (1.23 V) is too narrow to support most of the electrochemical couples used in Li-ion batteries. Hydrogen evolution at the anode presents the most severe challenge, as it occurs at a potential (2.21 to 3.04 V versus Li, depending on pH value) far above where most Li-ion battery anode materials operate. Even in trace amounts, hydrogen severely deteriorates the electrode structure during cycling. A common practice to suppress hydrogen evolution in aqueous electrochemistry is to adjust the alkalinity, so that the water reduction potential shifts downward to allow the use of anode materials otherwise prohibited under neutral or acidic conditions. However, as the overall electrochemical stability window of aqueous electrolytes remains constant, anodic stability against oxygen evolution suffers a corresponding compromise … In contrast to nonaqueous electrolyte systems, where cathode and anode materials often operate far beyond the thermodynamic stability limits of electrolyte components, kinetic protection from a solid-electrolyte interphase (SEI) in aqueous media has never been considered possible. Such interphases, situating between electrode surfaces and electrolyte, are formed by sacrificial electrolyte decomposition during the initial charging, and they constitute a barrier allowing ionic conduction but forbidding electronic conduction. Their presence substantially expands the usable electrochemical stability window of electrolytes. In conventional aqueous electrolytes, a protective interphase is absent because none of the decomposition products from water (H , O , or OH–) can deposit in a dense solid state. In the absence of interphases, aqueous Li-ion batteries are typically limited to low voltage ( The team formulated a “water-in-salt” electrolyte by dissolving lithium bis(trifluoromethane sulfonyl)imide (LiTFSI) at extremely high concentrations (molality >20 m) in water. This led to an anion-containing Li+ solvation sheath, which results in the formation of a dense solid interphase on the anode surface, mainly arising from anion reduction. When combined with the substantially reduced electrochemical activity of water at such a high concentration, the water-in-salt electrolyte provided an expanded electrochemical stability window of ~3.0 V. The team constructed a full aqueous Li-ion battery using a model electrochemical couple (LiMn O and Mo S ) and demonstrated an open circuit voltage (OCV) of 2.3 V. The cell was was cycled at nearly 100% coulombic efficiency for up to 1000 cycles at both low (0.15 C) and high (4.5 C) rates. According to Lt. Col. (Retired) Edward Shaffer, who heads the Army Research Laboratory’s Energy and Power Division, the significant potential advantages this new approach has over current batteries “could lead to thermally, chemically and environmentally safer batteries carried and worn by soldiers; safe, reduced-footprint energy storage for confined spaces, particularly submarines; and novel hybrid power solutions for military platforms and systems.” The UMD & ARL team compared the performance of their new “Water-in-Salt” battery with that of other aqueous battery systems. They showed that high stability of other aqueous batteries was achieved only at the expense of voltage and energy density and vice versa. However, the formation of the anode/electrolyte interphase in their “Water-in-Salt” electrolyte allowed them to break this inverse relationship between cycling stability and high voltage and to achieve both simultaneously. Researchers in the Li-ion battery field have recently found that previously ‘useless’ solvents could be made functional in Li-ion cells through the addition of high concentrations of salts. The work by Suo et al., extends this idea to the case of the solvent, water. By extending the operational voltage window to approximately 3 Volts, it is possible that a new generation of safer and possibly less expensive Li-ion cells could result. Only further R&D efforts will be able to verify the practicality of this discovery, so prudence is needed in assessing the potential of this, or any basic research advance. —Dalhousie University Professor Jeff Dahn (not involved in the study) This research received funding from the Department of Energy, Advanced Research Projects Agency-Energy (ARPA-E) (DEAR0000389) and support from the Maryland NanoCenter and its Nanoscale Imaging Spectroscopy & Properties Laboratory. This UMD lab is supported in part by the National Science Foundation. Modeling efforts were supported by the ARL Enterprise for Multiscale Research of Materials.
News Article | December 20, 2016
Four years ago hundreds of Canadian scientists gathered on Parliament Hill in Ottawa, donning their white lab coats to protest what they said was the “death of scientific evidence.” They held a mock funeral procession and prepared eulogies. Conservative Prime Minister Stephen Harper, they warned, appeared to be waging a war on science—imposing draconian restrictions on scientists’ engagement with the media and proposing a national science budget that slashed research funding and closed certain research centers. Some of those actions took Canadian scientists by surprise, and a number of them are warning their U.S. counterparts not to be similarly caught off guard following Donald Trump’s election victory in November. Several are offering to help U.S. scientists back up their data, and urging them to make their case to the public about the importance of their research—and of factual evidence itself. “There was a feeling that the government was not interested in expert opinion, and I think it’s the same kind of thing that you are probably going to see with the new [Trump] administration” in the U.S., says David Tarasick, a senior research scientist at Environment and Climate Change Canada (the equivalent of the U.S. Environmental Protection Agency). Tarasick says Harper’s government prevented him from speaking to the media about compelling research titled “Unprecedented Arctic Ozone Loss in 2011” for two weeks after the report was published in Nature. His agency simply denied interview requests without stating any reason, he says. Instead, that media office supplied “approved” statements to attribute to Tarasick, but he says he had never seen or approved that language himself. (The agency’s media office said at the time that the interview simply “cannot be granted,” according to the National Post). There were battles on other fronts, too. The Harper administration chose not to provide any monies for a large funding office that supported climate change research, and without those grants Canadian scientists often either changed focus or traveled to other countries where they believed they could get funding more easily. Those scientists often cited the toxic scientific atmosphere and dwindling research funds as their reason for leaving, says Thomas Duck, a professor of physics and atmospheric science at Dalhousie University in Nova Scotia. “In about six months my team of about 10 people went down to just myself and a graduate student. But my story is hardly unique. It was a common story of many research groups,” Duck says. “It takes decades to build up scientific capacity but it takes months to irretrievably destroy it.” President-elect Trump has already launched opening salvos against science and the press. He has expressed skepticism about climate change science (calling it a hoax created by the Chinese) and vaccine safety (once tweeting, “Why doesn’t the Obama administration do something about doctor-inflicted autism?”). He has shown disdain for the media and denied press access to outlets that have given him unfavorable coverage. He has also pledged to slash or shrink multiple federal science agencies. And Trump’s top picks for cabinet appointments—Scott Pruitt at the EPA, along with departmental nominees Rick Perry for Energy and Ryan Zinke for Interior—have expressed doubts about humans’ role in climate change, leaving many U.S. scientists to wonder what these actions augur for the future, and for their jobs. Some of them are already seeking a way out. Within 48 hours of last month’s presidential election, two U.S. climate change scientists contacted a Canadian colleague, Andrew Weaver, asking him to act as a job reference because they were going to (and did) seek jobs in Canada, says Weaver, who was a vocal critic of Harper while working as Canada Research Chair in Climate Modeling and Analysis at the University of Victoria. “It’s going to be a good time for Canadian science, I guess,” he says. Weaver has recently entered Canadian politics himself and is now an elected official in his provincial legislature. Ahead of next month’s presidential inauguration, thousands of U.S. scientists have already signed protest letters, and science organizations are offering to counsel the Trump transition team. Various Obama administration officials are also making the rounds with press conferences and interviews, seeking to cement their scientific legacy and publicly emphasizing the value of science. Citing bitter experience, our neighbors to the north have suggested further steps to safeguard science in this country. Following a recent skirmish over a Trump transition team request for the names of Department of Energy staffers who worked on climate change initiatives under Pres. Barack Obama, Canadian scientists are working with colleagues at the University of Pennsylvania library and a nonprofit called the Internet Archive to back up environmental data sets and materials—including research around air pollution and greenhouse gases—that they believe could be vulnerable under a Trump administration. “The Harper government closed many of the different science libraries in Canada,” Duck says. “It was done in a very chaotic fashion and we have almost certainly lost data that we used to have.” Weaver suggests U.S. scientists take other specific action, too. “I would say that the American academic scientists have a duty and a responsibility to get out there and communicate the value of the science they do. The public will only support the science if they understand its value. You don’t have to attack Trump, you just have to let people know why science is important,” he says. “Ultimately it is the public that sways governments—not any one or two scientists.” Americans could also look for a potential example in Canadian scientists’ recent actions to enshrine their ability to speak to the media, included as part of their recently negotiated contracts with the current government, Duck says. “Following the defeat last year of the Harper government, we vowed that no government should ever again silence science. This new provision will help ensure that remains the case now and in the future,” Debi Daviau, president of the Canadian union that helped hammer out the federal contracts, said in a public statement. “In Canada the government was subject to a lot of criticism because of the message control, and it’s generally regarded to have contributed significantly to their loss in last year’s election,” Tarasick notes. “One of the new government’s very first acts was to declare that scientists were free to speak to the media.”
News Article | November 15, 2016
The search is on for the 2016 International Brand Master, an exemplary educational marketing and branding professional, who will be recognized in the eighth annual International Brand Master Award competition sponsored by Educational Marketing Group (EMG), a premier U.S. brand development and marketing agency. Educational marketing professionals may nominate a colleague or themselves now through Friday, January 13, 2017, on EMG's website at http://emgonline.com/ibm-award/past-awards/2016-master/. "This is an excellent opportunity to bring attention to hard working education brand marketing professionals who do amazing work," said Bob Brock, president of EMG. International Brand Master Award nominees must be educational marketing professionals who: A top-notch international panel of judges comprised of EMG senior consultants, prior awardees, and several experienced volunteers from the profession carefully review the credentials and achievements of each nominee. This panel selects up to three finalists based on their credentials and achievements. Marketing practitioners from around the world then have the opportunity to vote for their candidate of choice from among the finalists. The scores of the select panel of judges and the public votes are combined to determine the International Brand Master. This year's winner will join an elite club of previous International Brand Masters: Since the creation of the award in 2009, nominations have come in from across the U.S., Belgium, Netherlands, Australia, the United Kingdom, and Thailand. Over the last six years, highly successful volunteer judges in the educational marketing field hailed from the U.S., Finland, Canada, England, Ireland, and South Africa. And during the public voting portion of the finalists during the last six years, over 8,000 votes were cast worldwide via EMG’s website, and on Facebook, Google+, and Twitter. International Brand Master Award Background The International Brand Master award was established in 2009. In 2015, EMG received nominations from the United Kingdom, the United States, Australia and Portugal. A blue-ribbon panel of volunteer international judges reviewed supporting materials provided by the nominees. The judges narrowed the pool of seven nominees to two from the United States, Shelly Brenckman, Texas A&M University, and Katie Kempf, Ursuline Academy, and one from Australia, Johanna Lowe, University of Sydney. The three finalists were asked to provide a 500-word and three-URL statement which were voted on by professional marketers from around the world. Over the previous seven years, over 9,000 votes from around the world were cast. The winner was chosen by a combination of public votes and the EMG panel of judges. For more information see: http://emgonline.com/ibm-award/. Educational Marketing Group Background EMG is a full-service, integrated brand development and marketing agency that provides custom-tailored research, brand development, creative development, new media services, professional development and media services for universities throughout North America. Headquartered in Denver, the company was established in 1997 and has operated in the education arena exclusively for 18 years. Clients have included North Carolina State University, Old Dominion University, University of Mary Washington, Washington State University, Virginia Tech, Cal Poly, Dalhousie University, University of Victoria, University of Colorado, University of Illinois, University of Michigan, University of Wyoming, and many others. Information: http://www.emgonline.com.
News Article | December 9, 2016
Dr. Neumeister has previously served as President of the Plastic Surgery Foundation, Plastic Surgery Research Council and a Leader in Translational Regenerative Medicine SOUTH PLAINFIELD, NJ--(Marketwired - Dec 9, 2016) - Majesco Entertainment, Inc. ( : COOL) ("Majesco") following announcement that it had signed a definitive merger agreement with PolarityTE, Inc. ("Polarity") www.polarityte.com announced it has appointed Michael W. Neumeister, MD, FRCSC, FACS as Chief Medical Officer (http://www.siumed.edu/surgery/plastics/cvs/neumeister_cv.html). Dr. Neumeister was formerly President of the Plastic Surgery Foundation and Plastic Surgery Research Council and is a Leader in Regenerative Medicine (http://www.siumed.edu/surgery/plastics/cvs/MWN%20CV.pdf). Following satisfaction of the conditions to closing, including approval of stockholders, Polarity will be acquired by Majesco, and will operate as a wholly-owned subsidiary of Majesco, which will change its name to Polarity in connection with the contemplated transaction. "Polarity seeks to alter the paradigms of regenerative medicine and patient-specific tissue engineering for the future. It is with these ambitious goals in mind that I am pleased to announce world renowned plastic and reconstructive surgeon Dr. Michael Neumeister has agreed to join as Chief Medical Officer of PolarityTE™. Beyond his tremendous expertise in some of the most complex reconstructive procedures performed, he has remained a leader and mentor in the field and an innovator in pragmatic translational regenerative medicine," said Chief Executive Officer and Chairman Dr. Denver Lough. "I am extremely excited to join the Polarity Team and help transform the landscape of translational tissue engineering and reconstructive surgery. I believe I can add tremendous value with a large network of clinical thought leaders and practical viewpoint on the application of the technology. Dr. Lough and I have a close working relationship and I consider him to be one of the most gifted and brilliant innovators in regenerative medicine, and it is an honor to be brought on to his team in this role. I have no doubt, he will change field as we know it," said Dr Neumeister. About PolarityTE PolarityTE, Inc. is the owner of a novel regenerative medicine and tissue engineering platform developed and patented by Denver Lough MD, PhD. This radical and proprietary technology employs a patients' own cells for the healing of full-thickness functionally-polarized tissues. If clinically successful, the PolarityTE platform will be able to provide medical professionals with a truly new paradigm in wound healing and reconstructive surgery by utilizing a patient's own tissue substrates for the regeneration of skin, bone, muscle, cartilage, fat, blood vessels and nerves. It is because PolarityTE uses a natural and biologically sound platform technology, which is readily adaptable to a wide spectrum of organ and tissue systems, that the company and its world-renowned clinical advisory board, are poised to drastically change the field and future of translational regenerative medicine. More info can be found online at www.polarityte.com. Welcome to the Shift™. About Michael W. Neumeister, MD, FRCSC, FACS Professor & Chairman - Department of Surgery The Elvin G. Zook Endowed Chair in Plastic Surgery Microsurgery/Research Lab Director Director: Memorial Medical Center Regional Burn Unit Director: Memorial Medical Center Wound Center Southern Illinois University School of Medicine, Springfield, IL Dr. Neumeister is Professor & Chairman of the Department of Surgery and The Elvin G. Zook Endowed Chair in Plastic Surgery at Southern Illinois University School of Medicine in Springfield, IL. He received his medical degree from the University of Toronto and previously completed a degree in physiology and pharmacology at the University of Western Ontario. Dr. Neumeister began his residency at Dalhousie University in Halifax, Nova Scotia in general surgery and went on to complete his plastic surgery residency at the University of Manitoba. He continued his training as a microsurgery fellow at Harvard University's Brigham & Women's Hospital in Boston and completed a one year hand and microsurgery fellowship at Southern Illinois University School of Medicine. Dr. Neumeister is board certified in plastic surgery by the Royal College of Surgeons of Canada and the American Board of Plastic Surgery. He has also received his Certificate in (SOTH) Surgery of The Hand. Dr. Neumeister has received awards for presentations given regionally, nationally and internationally, has over 150 book chapters and articles, and has multiple research interests in tissue engineering and regenerative medicine. Dr. Neumeister is the Editor in Chief of the official AAHS journal HAND. He is the past President of the American Society of Reconstructive Microsurgery, American Association for Hand Surgery, The Plastic Surgery Foundation (The Research Body of The American Society of Plastic Surgeons), Plastic Surgery Research Council, and the Midwest Association of Plastic Surgeons. His memberships include the American Society of Plastic Surgeons, Plastic Surgery Foundation, Plastic Surgery Research Council, American Association for Hand Surgery, American Society of Reconstructive Microsurgery, American Society for Surgery of the Hand, American Burn Association, American Council of Academic Plastic Surgeons and the American Association of Plastic Surgeons where he also serves as an elected official on several of their committees. Dr. Neumeister has received awards for presentations given regionally, nationally and internationally and has over 150 published manuscripts and book chapters. Dr. Neumeister's research interests include: allotransplantation, tissue engineering, the role of stem cells in reconstruction, ischemia reperfusion, peripheral nerve, and burn modulation. Forward-Looking Statements Certain statements contained in this release are "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995. Forward looking statements contained in this release relate to, among other things, the Company's ongoing compliance with the requirements of The NASDAQ Stock Market and the Company's ability to maintain the closing bid price requirements of The NASDAQ Stock Market on a post reverse split basis. They are generally identified by words such as "believes," "may," "expects," "anticipates," "should" and similar expressions. Readers should not place undue reliance on such forward-looking statements, which are based upon the Company's beliefs and assumptions as of the date of this release. The Company's actual results could differ materially due to risk factors and other items described in more detail in the "Risk Factors" section of the Company's Annual Reports filed with the SEC (copies of which may be obtained at www.sec.gov). Subsequent events and developments may cause these forward-looking statements to change. The Company specifically disclaims any obligation or intention to update or revise these forward-looking statements as a result of changed events or circumstances that occur after the date of this release, except as required by applicable law.
News Article | December 3, 2016
CANCUN, MEXICO--(Marketwired - Dec. 3, 2016) - Canada is taking action in the conservation and long-term protection of marine biodiversity. At the recent Convention on Biological Diversity at the Conference of the Parties (COP13), the Honourable Dominic LeBlanc, Minister of Fisheries, Oceans and the Canadian Coast Guard, announced a new initiative that will facilitate meeting Canada's marine conservation targets, and another that demonstrates Canada's commitment to ensuring the long-term viability of the Sargasso Sea, a globally significant marine ecosystem. The Minister announced, on behalf of the Honourable Catherine McKenna, Minister of Environment and Climate Change, the proposed establishment of Scott Islands marine National Wildlife Area (NWA), the first under the Canada Wildlife Act. This area is home to over two million seabirds, making it the highest concentration of seabirds as well as the most important nesting and breeding ground for seabirds in British Columbia. Minister LeBlanc discussed additional ways Canada will achieve meeting its international targets to increase the amount of marine and coastal areas that are protected to 5% by 2017 and 10% by 2020. Canada's plan consists of advancing work in areas progressing towards establishment, such as the proposed Lancaster Sound National Marine Conservation Area, and several proposed Oceans Act Marine Protected Areas, including Hecate Strait and Queen Charlotte Sound Glass Sponge Reefs, Laurentian Channel and Banc des Américains. The Minister also highlighted progress achieved for the designation of St. Anns Bank for which stakeholder input will be sought in the near future. Finally, Minister LeBlanc signed the 'Hamilton Declaration on Collaboration for the Conservation of the Sargasso Sea'. The Sargasso Sea, located near Bermuda, provides habitat, spawning areas, migration pathways and feeding ground to a diverse range of flora and fauna, including some endangered and commercially important species. The Convention focused on actions to ensure the conservation, sustainable use, management, and restoration of biological diversity and ecosystems. While at the Convention, the Minister also continued discussions with his international counterparts on other effective area-based conservation measures and the need for science-based decision making. "Conservation and protection of marine environments is important for aquatic biodiversity and the fisheries sector. Our Government is taking concrete steps to reaching our international targets for protecting our marine and coastal areas. The proposed designation of Scott Islands marine National Wildlife Area is a great example of effective ocean management and marine conservation. The Department of Fisheries and Oceans has developed science-based guidance to help us determine other effective area-based conservation measures. I look forward to working with my provincial counterparts on these important initiatives, and to hearing the views of Canadians on how the proposed regulations assure the protection of identified key species and habitats." - The Honourable Dominic LeBlanc, Minister of Fisheries, Oceans and the Canadian Coast Guard "I am delighted that Scott Islands marine National Wildlife Area will be the first marine National Wildlife Area in Canada. The area is home to 40% of all breeding seabirds in the Canadian Pacific. I look forward to working with my colleague the Minister of Fisheries, Oceans and the Canadian Coast Guard and stakeholders to hear their views on the proposed protections and how they can be improved, not only for sea birds but for other key species and habitats there and elsewhere in the ecosystem." - The Honourable Catherine McKenna, Minister of Environment and Climate Change Canada "The Sargasso Sea is the birthplace of all American and European eels. We have a regulated eel fishery in the Maritime Provinces, and it's therefore important that Canada works with other nations in the protection of this unique habitat. I heartily applaud the Honourable Dominic LeBlanc, Minister of Fisheries, Oceans and the Canadian Coast Guard, for leading Canada in becoming a signatory to the Hamilton Declaration in order to collaborate with other nations to preserve this important ecosystem." "I am delighted that Canada will participate in the stewardship of this unique and vitally important marine environment. As a tri-coastal country, Canada has extremely valuable experience that will be a great asset to the Sargasso Sea conservancy effort." - Government of Bermuda Minister of the Environment, The Hon. N. Cole Simons, JP, MP. Canada Signs the 'Hamilton Declaration on Collaboration for the Conservation of the Sargasso Sea' The Sargasso Sea, located near Bermuda, is a unique, high-seas marine ecosystem. The ecologically and biologically significant area is unique because it is an area of open ocean bounded on all sides by the clockwise flow of major ocean currents. The area is named for the Sargassum seaweed - a holopelagic, golden drift algae that forms extensive floating mats on the surface of the ocean. This unique ecosystem is home to a wide range of species, including several identified for protection. It provides habitat, spawning areas, migration pathways, and feeding groups to a diverse range of flora and fauna, including some endangered and commercially important species. The majority of the ecosystem lies beyond national jurisdictions. The 'Hamilton Declaration on Collaboration for the Conservation of the Sargasso Sea' was first signed in Hamilton, Bermuda on March 11, 2014. The Declaration resulted in the creation of the Sargasso Sea Commission, which includes a number of international signatories, including Bermuda, United Kingdom, United States of America, and Monaco, as well as collaborating partners, such as the International Union for the Conservation of Nature (IUCN), the World Wildlife Fund (WWF), and Dalhousie University Marine and Environmental Law Institute, working together to protect the area. The Commission uses the best available scientific research to better understand the unique ecosystem and support efforts to conserve and protect the Sargasso Sea. The Government of Canada remains committed, both domestically and internationally, to conserving and protecting precious marine environments. Signing the Declaration ensures the long-term viability of the globally significant Sargasso Sea ecosystem. The area plays an important role in the wider North Atlantic ecosystem, serving as habitat, foraging and spawning grounds and as a migratory corridor for many species important to Atlantic Canada. The mats formed by the Sargassum algae are home to many species and provide a protective 'nursery' for juvenile fish and turtles. The area is considered the primary spawning ground for American eel, which then migrates to freshwater and is harvested commercially in shore-based fisheries on Canada's Atlantic coast. Most recently, in the summer of 2016, Fisheries and Oceans Canada conducted oceanographic and seabed research in the area as part of a scientific expedition from Nova Scotia to Bermuda. The proposed Scott Islands Protected Marine Area, also known as the Scott Islands marine National Wildlife Area (NWA), located off the northern tip of Vancouver Island, will be the first protected marine area established under the Canada Wildlife Act. The establishment of the NWA will increase marine protection in Canada by 11,546 km2, and would enable effective long-term conservation of the highest concentration of breeding seabirds in the Canadian Pacific, as well as many other marine species, including species listed under the Species at Risk Act. The area sustains 90 percent of Canada's Tufted Puffins, 95 percent of Pacific Canada's Common Murre, 50 percent of the world's Cassin's Auklets and 7 percent of the global population of Rhinoceros Auklet. The surrounding waters provide key feeding habitat for the birds that nest on the islands, and also attract an additional 5-10 million migratory birds annually that may travel vast distances across the Pacific to feed on the abundance of small fish and zooplankton in the area. The Government of Canada committed to establishing the proposed Scott Islands marine NWA in Budgets 2007 and 2013. Environment and Climate Change Canada (ECCC) is leading the establishment process, and target date for publication in Canada Gazette, Part I of the proposed Scott Islands Protected Marine Area Regulations is December 2016. Establishment of the Scott Islands NWA, along with the implementation of conservation measures via the Regulations, would prevent activities from occurring in the marine National Wildlife Area that would threaten the vitality of the Scott Islands as important habitat for seabirds. The prohibition against fishing for Pacific sand lance, Pacific saury and North Pacific krill will be of benefit to the many marine species that feed on these fish, not just the seabirds. Establishment of the marine NWA will allow for an enhanced focus on monitoring and research in order to meet the conservation objectives for the area, the main one being to conserve migratory seabirds. The establishment of the Scott Islands marine National Wildlife Area will complement existing provincial protected area designations for the five islands that make up the Scott Islands archipelago.
News Article | November 14, 2016
WINNIPEG, MB--(Marketwired - November 14, 2016) - 3D Signatures Inc. (TSX VENTURE: DXD) (the "Company" or "3DS") is pleased to introduce its Clinical and Scientific Advisory Board (CSAB), comprised of world-renowned physicians and researchers. The CSAB, made up of external experts, will serve as a resource to Dr. Sabine Mai, Director and Chair of 3DS' Clinical and Scientific Advisory Board and 3DS' CEO, Jason Flowerday. The CSAB will help guide the clinical development of 3DS' proprietary genomic analysis software from research, right through to validation and regulatory approval. The Company is currently focused on Prostate Cancer, Hodgkin's Lymphoma, Multiple Myeloma, and Alzheimer's disease. Dr. Sabine Mai is a tenured Professor of Physiology and Pathophysiology, Biochemistry and Medical Genetics, Human Anatomy and Cell Science, University of Manitoba. She is also Director of The Genomic Centre for Cancer Research and Diagnosis (GCCRD) at University of Manitoba. Dr. Mai is an internationally known researcher who has more than one hundred publications related to research on Genomic Instability and the 3D nuclear organization in cancer and Alzheimer's disease. Most recently she has contributed to a library of patents related to her work on 3D Genomic Analysis. She is the recipient of numerous academic awards including the Braidwood Jackson Memorial Award; the Dr. Saul Highman Memorial Award; the Rh Award (Basic Science); the J&J Cognition Challenge (2013). She was recognized in 2015 as one of the Top 100: Canada's Most Powerful Women and has recently accepted an Editorial Board Member position with Genes, Chromosomes and Cancer, a high-profile peer-reviewed academic journal. Dr. Anderson is the Kraft Family Professor of Medicine at Harvard Medical School, as well as Director of the Lebow Institute for Myeloma Therapeutics and Jerome Lipper Multiple Myeloma Center at Dana-Farber Cancer Institute. He is a Doris Duke Distinguished Clinical Research Scientist and American Cancer Society Clinical Research Professor. After graduating from Johns Hopkins Medical School, he trained in internal medicine at Johns Hopkins Hospital, and then completed hematology, medical oncology, and tumor immunology training at the Dana-Farber Cancer Institute. Over the last three decades, he has focused his laboratory and clinical research studies on multiple myeloma. He has developed laboratory and animal models of the tumor in it is microenvironment which have allowed for both identification of novel targets and validation of novel targeted therapies, and has then rapidly translated these studies to clinical trials culminating in FDA approval of novel targeted therapies. His paradigm for identifying and validating targets in the tumor cell and its milieu has transformed myeloma therapy and markedly improved patient outcome. Dr. Klotz is internationally recognized for his contributions to the treatment of prostate cancer, notably for pioneering the adoption of Active Surveillance as a standard aspect of patient care. Dr. Klotz obtained his medical degree and residency training from the University of Toronto with a special fellowship in uro-oncology and tumour biology at Memorial Sloan Kettering Cancer Centre, New York. He is a widely published uro-oncologist who serves on the board or heads many medical/scientific organizations. He is a Professor, Department of Surgery, University of Toronto, past Chief of Urology, Sunnybrook Health Sciences Centre, Toronto, and Chairman, World Uro-Oncology Federation. Dr. Klotz was awarded the Order of Canada in 2014 for his contribution to prostate cancer treatment. Dr. Knecht established himself as a prominent haematologist through his ground-breaking translational research on lymphoma biology. His current focus is on the molecular events leading to the transition from the mononuclear Hodgkin to the multinuclear Reed-Sternberg cell and the impact of 3D nuclear telomere organization on this transformation. Dr. Knecht received his medical degree from the University of Zurich, Switzerland with post-graduate work under both Maxime Seligmann (Haematology) and Karl Lennert (Haematopathology) in Paris and Kiel, respectively. Dr. Knecht is currently a Professor of Medicine and Chief, Division of Haematology at McGill University and Jewish General Hospital, Montreal. Dr. Drachenberg is a urologic oncologist and researcher and strong proponent of Active Surveillance for prostate cancer patients. Dr. Drachenberg attended medical school at the University of British Columbia and urology residency at Dalhousie University. He is an American Foundation of Urology Scholar with fellowship training in urologic oncology at the National Cancer Institute in Bethesda, Maryland. He founded the laparoscopic urology program and prostate brachytherapy, cryotherapy, and HIFU programs at the University of Manitoba where he works as assistant professor of surgery and director of research for the Manitoba Prostate Center and Section of Urology and Chair of the Genito-Urinary disease site group, CancerCare Manitoba. Dr. Kotb completed his medical residency training in Paris, France, and then became a staff member at Paris XI University. He joined the Hematology-Oncology team at Sherbrooke University (QC, Canada) in 2005 as an Assistant, then Associate Professor. He also worked as the Director of Hematology undergraduate education, Head of the supra-regional team of Hematological Neoplasia and Head of the Institutional Oncology Quality Sub-committee. Late 2011, he moved to British Columbia to work at the BC Cancer Agency as an Oncologist/Hematologist, Associate Professor at the University of British Columbia and affiliate Professor at the University of Victoria. He joined the team at CancerCare Manitoba in September 2014. His practice and research activity will be focused on lymphoid neoplasia, primarily myeloma and lymphoma. Dr. Cremer is an internationally-recognized scientist specializing in the study of nuclear architecture. He is one of the pioneers of interphase cytogenetics and comparative genomic hybridization (CGH). These methods have become widely used tools for cytogenetic analyses of chromosomal imbalances. He is a corresponding member of the Heidelberg Academy for Sciences and Humanities since 2000, a member of Germany's National Academy of Sciences Leopoldina since 2006, and an honorary member of both the European Cytogenetics Association (ECA) and the German Society of Human Genetics since 2011, as well as the recipient of the medal of Honor of this Society. Dr. Cremer is an independent expert to 3DS. "The newly formed CSAB will be invaluable in guiding our clinical programs," said Dr. Sabine Mai, Company Director and Chair of 3DS' Clinical and Scientific Advisory Board. "Each member is a distinguished leader in their field and can bring insights that will help us achieve our objectives: to validate and secure the approval of accurate and minimally invasive first-in-class biomarkers that allow clinicians to personalize treatments and improve outcomes for cancer and Alzheimer's disease patients." The Company recently announced participation in a major clinical trial for prostate cancer diagnosis and management known as PRECISE (PRostate Evaluation for Clinically Important disease MRI vs Standard Evaluation procedures). The trial marks the Company's first step toward validation and approval of clinical risk assessment tests for prostate cancer. It is currently being tested as a new blood-based biomarker to accurately stratify Prostate Cancer patients into risk groups. Such a tool does not currently exist for prostate cancer patients. For more information about the PRECISE Trial and Prostate Cancer Canada, please visit their website at http://www.prostatecancer.ca. 3DS (TSX VENTURE: DXD) is a personalized medicine company with a proprietary software platform based on the three-dimensional analysis chromosomal signatures. The technology is well developed and supported by 16 clinical studies on over 1,500 patients on 13 different cancers and Alzheimer's disease. Depending on the desired application, the technology can measure the stage of disease, rate of progression of disease, drug efficacy, and drug toxicity. The technology is designed to predict the course of disease and to personalize treatment for the individual patient. For more information, visit the Company's new website at http://www.3dsignatures.com. This news release includes forward-looking statements that are subject to risks and uncertainties. Forward-looking statements involve known and unknown risks, uncertainties, and other factors that could cause the actual results of the Company to be materially different from the historical results or from any future results expressed or implied by such forward-looking statements. All statements within, other than statements of historical fact, are to be considered forward looking. In particular, the Company's statements that it expects to benefit greatly from its association with the individuals named in this news release is forward-looking information. Although 3DS believes the expectations expressed in such forward-looking statements are based on reasonable assumptions, such statements are not guarantees of future performance and actual results or developments may differ materially from those in forward-looking statements. Risk factors that could cause actual results or outcomes to differ materially from the results expressed or implied by forward-looking information include, among other things: market demand; technological changes that could impact the Company's existing products or the Company's ability to develop and commercialize future products; competition; existing governmental legislation and regulations and changes in, or the failure to comply with, governmental legislation and regulations; the ability to manage operating expenses, which may adversely affect the Company's financial condition; the Company's ability to successfully maintain and enforce its intellectual property rights and defend third-party claims of infringement of their intellectual property rights; adverse results or unexpected delays in clinical trials; changes in laws, general economic and business conditions; and changes in the regulatory regime. There can be no assurances that such statements will prove accurate and, therefore, readers are advised to rely on their own evaluation of such uncertainties. We do not assume any obligation to update any forward-looking statements. Neither the TSX Venture Exchange nor its Regulation Service Provider (as that term is defined in the policies of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this release.
News Article | November 23, 2016
OTTAWA, ONTARIO--(Marketwired - Nov. 23, 2016) - Amika Mobile is pleased to announce its CEO, Sue Abu-Hakima has been named a Women's Executive Network (WXN) 2016 Canada's Most Powerful Women: Top 100 Award Winner. She was also named a Top 100 by the WXN in 2015. Launched in 2003, the Top 100 Awards celebrate the incredible accomplishments of Canada's top female executive talent as well as their organizations and networks. Sue Abu-Hakima will receive the Sun Life Trailblazers and Trendsetters award for being an innovator and one of the rare women in technology who is both a Founder and CEO, and who has exited one start-up and is working on her second. Sue has 30 International patents in technology in AI, messaging public safety, and security. She has set an example as a tech Founder/CEO for 17 years and has had a strong impact on women entrepreneurs while contributing to non-profit boards for 29 years. Sue will be honoured during a gala celebration at the Metro Toronto Convention Centre on November 24. Sue Abu-Hakima co-founded Amika Mobile, joining as CEO in 2007, and has had a profound impact by leading the company through its development and launch of new, innovative products, which have recently garnered top awards in public safety and security. She also drives partnerships and customer acquisition for Amika Mobile, successfully signing marquee customers such as CBSA in Canada and the Albany VA Hospital in the US, amongst others. As a proud supporter of women in leadership and technology, Amika Mobile works to create the necessary conditions and opportunities for women to help them thrive and succeed within high tech and setting a strong example for women in business. "Receiving the Top 100 Trailblazer and Trendsetters award from the WXN for the second year in a row, is a super honour and I hope to continue to set a strong example for young women to thrive in tech today on the web, in social media, in security or with mobile apps. It is getting easier to start-up today than it was 16 years ago and I hope to continue to inspire and mentor the next generation." said Sue Abu-Hakima, Co-Founder/CEO Amika Mobile. The Top 100 Awards serve to recognize talented leaders in the private, public and not-for-profit sectors and to inspire the current and next generation to push the boundaries of what's possible. "Women are not just leading companies, headlines and new deals, we're doing so in record numbers. In addition to closing the gender gap for participation in post-secondary education and the workforce, we're excelling at the top levels of every sector," says WXN Owner and CEO, Sherri Stevens. "When WXN created Canada's Most Powerful Women: Top 100 Awards, part of the purpose was celebration. By recognizing a community of now 939 remarkable women, we get the opportunity to look back and appreciate the hard work and hurdle jumping it took to get here." Sue Abu-Hakima joins a prestigious community of past Award Winners, including Canada's most iconic women trailblazers: Margaret Atwood, best-selling author; Dr. Roberta Bondar, astronaut; Arlene Dickinson, chief executive officer, Venture Communications; Christine Magee, president, Sleep Country Canada; Michaëlle Jean, former Governor General of Canada; Heather Reisman, founder and chief executive officer, Indigo Books & Music; and, Kathleen Taylor, chair of the board, Royal Bank of Canada. The full list of WXN's 2016 Canada's Most Powerful Women: Top 100 Award Winners can be found at https://www.wxnetwork.com/top-100/top-100-winners/. Sue Abu-Hakima is Co-Founder/CEO of Amika Mobile, focused on situational awareness, communications and control in critical and emergency situations. During 34 years in technology, Sue established an exemplary record as an Industry leader, employer and technology pioneer. Sue holds 30 International patents in content analysis, communications and security. As many as 35 Global 100 Companies have cited her pioneering patents. Sue is a rare woman technology CEO with a reputation for excellence and innovation. As a two-time start-up founder/CEO, she forms boards of directors and advisors and directs business strategy. Her leadership is key in securing financing and forming effective teams. Her first start-up, AmikaNow! spun out of NRC government R&D labs in 1999, was focused on AI and automatic content analysis. Its Compliance Business was acquired by Entrust in 2004. As Entrust VP Content Technology, she transitioned the acquisition. She has created over 200 high tech jobs in her start-ups. Sue holds a Bachelor of Engineering from McGill and honours Masters and Doctorate degrees in AI from Carleton University. Sue has served on boards for 29 years. She served as Vice Chair and Director for Ontario Centers of Excellence (OCE) for 8 years, and an Advisor on the Private Sector Advisory Board for National Centers of Excellence (NCE) for NSERC for 6 years. She is on the Big Data Institute Advisory Board of Dalhousie University and McGill University's strategic advisory board. Sue's companies have won 18 awards including Top 10 Company to watch by IDC, ASIS Judge's Choice and Security's Best Accolades and Top 5 and Top 10 Angel Backed Company in Ontario and Nationally from NACO. She has published and presented over 125 publications. Often an invited speaker, she has spoken at ASIS, RSA, Inbox, NetSeC, CTIA, etc. Sue was invested into the Order of Ontario in 2011 and was given the Queen Elizabeth II Medal for Service to Canada in June 2012. Sue was named a Top 25 Women of Influence in Canada for Business in 2014. Sue was also a WXN Top 100 honouree in 2015. Follow on Twitter: @AmikaAlert , LinkedIn Profile https://www.linkedin.com/in/suhayya - Suhayya Abu-Hakima, See Wikipedia https://en.wikipedia.org/wiki/Suhayya_Abu-Hakima About Amika Mobile: Amika Mobile Corporation is privately held specializing in critical and emergency communication and control. Its flagship product, the Amika Mobility Server (AMS), addresses IOT and BYOD security and is ideal for alert/response in enterprise, community, airport, sports arena, shopping center and campus where visitors may not always be pre-registered in a contacts database since the AMS can auto-discover mobile devices for emergency alert/response. AMS alerts securely over wire or mobile to ANY layer including WiFi, SMS, Email, VoIP, PA systems, Message Boards, Twitter, RSS Feeds, Facebook, etc. AMS and Amika®Panic can trigger lockdowns and alerts based on disparate events from gunshot sensors, access control, fire panels, cameras, wall mounted, desktop or mobile panic buttons, etc. Amika® Situation Commander tracks event alert/response in real-time. AMS delivers advisory government alerts from NOAA, IPAWS, NAAD System, Alert Ready and MASAS in CAP /CAP-CP formats. Amika Mobile has won 18 awards and sells products through partners. See www.amikamobile.com At WXN, we inspire smart women to lead. WXN delivers innovative networking, mentoring, professional and personal development to inform, inspire, connect and recognize our global community of more than 22,000 women, men and their organizations. WXN enables our partners and corporate members to become and to be recognized as employers of choice and leaders in the advancement of women. Founded in 1997, WXN is Canada's leading organization dedicated to the advancement and recognition of women in management, executive, professional and board roles. WXN is led by CEO Sherri Stevens, owner of the award-winning, multi-million dollar Workforce Management Company Stevens Resource Group Inc., which she established in 1990. In 2008, WXN launched in Ireland, followed by London, UK in 2015, creating an international community of female leaders. More information and details are available at www.wxnetwork.com or www.top100women.ca.
News Article | January 27, 2016
In the early fifties, before Richard Feynman famously seeded the concept of nanoscience in his 1959 talk “there’s plenty of room at the bottom” , and well before the concept of nanotechnology became popular in the late 80’s, a significant research effort was already underway into the fundamental nanoscience associated with high-field effects at surfaces and the resulting emission of ions and electrons . Born from this work, in 1955, field ion microscopy (FIM) became the first true atomic scale microscopy technique, allowing us to ‘see atoms’ for the very first time . The technique, invented by Erwin Müller in 1951 employed a specimen shaped into a sharp point, enabling it to act as a point projection field ion emitter. The specimen was cooled to 78K in the presence of He gas. This gas was adsorbed and subsequently field ionized and detected, with the distribution of detected atoms showing the arrangement of the specimen atoms at the surface of the tip. Sixty years on, this seminal work by Erwin Müller has spurred important and wide-ranging research, including many significant discoveries and inventions . Progressive field evaporated of surface atoms can be detected  and their positions reconstructed to create high-resolution 3D atom maps in a technique known as atom probe tomography , which has become an established microscopy technique. It’s use in materials characterisation has led to ground-breaking research including the first 3D images of segregation to dislocations , understanding the growth of nanowires , determining the kinetics of elemental steps of catalytic surface reactions , revealing precipitation pathways in important engineering alloys  and confirmation of the dating of the oldest minerals on earth , to name just a few examples. Other contributions from field-emission science include the development of the liquid metal ion source that now forms the basis of focused ion beam instruments , field electron emission from new forms of emitter  along with the sustained development of theory around high-field effects at surfaces . It is timely that we recognize these exceptional contributions. The International Field Emission Society (IFES) originally grew from pioneering research on high-field nanoscience, and supports the development and application of techniques and instruments based on these effects. It has hosted symposia since 1952 occurring every one to two years. In 2016, this conference, “Atom Probe Tomography & Microscopy (55th IFES)” will be held in Gyeongju, South Korea (June 12-17). At the event, the Steering Committee of the IFES (see note at end of this article for a list of members) is proud to award an inaugural round of “Fellows of the International Field Emission Society”, elected in recognition of eminence in the field of field emission, field ionization, and related phenomena. These individuals have been nominated and elected by their peers for outstanding research that has pushed the frontiers of knowledge in the field. Many have also undertaken distinguished service to the IFES. Those to be honored as IFES fellows in 2016 are listed below: Hans-Olof Andren, Chalmers University of Technology: For development of atom probe techniques, and for his use of atom probe instruments as materials science tools to study the detailed microstructure of primarily metallic materials. Didier Blavette, Université de Rouen: For unique contributions to atom probe field ion microscopy spanning the fundamental physics of the technique, instrumentation, and cutting-edge materials characterization. Alfred Cerezo, University of Oxford: For development of the position sensitive atom probe, which opened new dimensions and perspectives in both material science and instrumentation. Paul Cutler, The Pennsylvania State University: For working on theory of field electron and ion emission over more than 50 years, developing quantum mechanical models to explain and predict the behavior of field electron emitters. Richard Forbes, University of Surrey: For his many contributions to the growth of the theory and understanding of field electron and ion emission as well as his contributions to the society. Georgiy Fursey, St Petersburg University of Telecommunications: For wide-ranging, outstanding contributions to field electron emission science and technology, particularly explosive emission and emission from semiconductors. Robert Gomer, University of Chicago: For outstanding contributions to science, especially areas of field electron and ion emission and their application to problems in surface chemistry, and for public service. Kazuhiro Hono, National Institute for Materials Science: For key contributions to the growth of atom probe, developments in instrumentation, and broad utilization of the technique to impact the study of magnetic materials and precipitation hardening. Gary Kellogg, Retired: For fundamental technical contributions to laser-pulsed atom probe instrumentation and numerous aspects of surface and materials science, and for extraordinary service to the nanoscience community. Thomas Kelly, Cameca Inc.: For revolutionizing atom probe technology with the invention of the LEAP, and for service to the IFES community as President of the society. Hans-Juergen Kreuzer, Dalhousie University: Published more than 325 papers, 8 books, and 6 patents in the area of physics and chemistry of high electric fields. Norbert Kruse, Washington State University: For sustained contributions towards understanding chemical physics at materials surfaces and outstanding service to the high field nanoscience and atom probe communities. Allan Melmed, Retired: One of the most distinguished scientists of the IFES community, with a lifetime experience in field emission since his PhD thesis with the late EW Müller. Michael Miller, Retired: For seminal contributions in the development and application of atom probe tomography as demonstrated by his 600+ publications, service to the community, and impactful collaborations with numerous international scientists and engineers in their development and use of atom probe tomography. Marwan Mousa, Mu'tah University: For outstanding contributions to field emission science and for service to the society including organization of the 45th IFES. Osamu Nishikawa, Kanazawa Institute of Technology: For outstanding contributions to atom probe becoming a mainstream scientific instrument in hundreds of laboratories around the world. John Panitz, University New Mexico: As one of the inventors of the atom probe technique, John Panitz’ contributions and vision for the technique enabled its large acceptance in the international realm of materials characterization. Simon Ringer, The University of Sydney: For outstanding research in atom probe science, sustained IFES community service, including as Vice President and conference organiser and his role in training a new generation of field emission scientists. Guido Schmitz, University of Stuttgart: For his contribution to understanding diffusion and other atomic scale metallurgical processes studied using atom probe tomography. David Seidman, Northwestern University: Having advised more than 120 individuals and with 450+ publications, David Seidman's materials research based on APT and technique developments has laid a solid groundwork for atom probe groups worldwide. George Smith, University of Oxford: For more than 45 years of contributions and commitment to the field of atom probe field ion microscopy. Krystyna Stiller, Chalmers University of Technology: For fruitful use and development of atom probe techniques contributing to understanding of radiation damage, phase transformations, interfacial segregation and high temperature oxidation, and for promoting atom probe techniques. Lynwood Swanson, FEI: For outstanding scientific contributions to characterisation and development of field electron/ion emitters, and technical and managerial leadership of FEI Company in commercially developing these emitters and related instruments. Tien Tsong, Academia Sinica: For observation of the interaction between adsorbates on metal surfaces and for seminal research involving the use of a laser to promote thermal field evaporation. The Steering Committee of the IFES currently consists of:  Feynman RP. There's Plenty of Room at the Bottom. Engineering and Science 1960:22-36.  Cerezo A, Godfrey TJ, Smith GDW. Application of a position-sensitive detector to atom probe microanalysis. Review of Scientific Instruments 1988;59:862-6.  Perea DE, Hemesath ER, Schwalbach EJ, Lensch-Falk JL, Voorhees PW, Lauhon LJ. Direct measurement of dopant distribution in an individual vapour-liquid-solid nanowire. Nature Nanotechnology 2009;4:315-9.  Kruse N, Abend G, Block JH. The kinetics of adsorption and thermal desorption of NO on stepped Pt single crystal surfaces. The Journal of Chemical Physics 1988;88:1307-12.  Ringer SP, Hono K. Microstructural evolution and age hardening in aluminium alloys: atom probe field-ion microscopy and transmission electron microscopy studies. Materials Characterization 2000;44:101-31.  Valley JW, Cavosie AJ, Ushikubo T, Reinhard DA, Lawrence DF, Larson DJ, et al. Hadean age for a post-magma-ocean zircon confirmed by atom-probe tomography. Nature Geoscience 2014;7:219-23.  Li Z, Xu N, Kreuzer HJ. Coherent field emission image of graphene predicted with a microscopic theory. Physical Review B - Condensed Matter and Materials Physics 2012;85.  Forbes RG, Edgcombe CJ, Valdrè U. Some comments on models for field enhancement. Ultramicroscopy 2003;95:57-65.
News Article | November 22, 2016
Cubresa Inc., a medical imaging company that develops and markets molecular imaging systems, today announced that their compact SPECT (Single-Photon Emission Computed Tomography) scanner was used in a study by Dalhousie University and Mount Saint Vincent University researchers in Halifax, Nova Scotia to help evaluate the diagnostic potential of a new molecular label that could lead to the early detection of Alzheimer’s disease in living patients. Alzheimer’s disease (AD) is a progressive neurological condition that causes dementia and for which there is no FDA-approved treatment for the underlying disease. There is a need for a non-invasive way to detect and diagnose the disease in living patients because definitive diagnosis still requires post mortem examination. The study was performed by Dr. Sultan Darvesh and his research group at BIOTIC (Biomedical Translational Imaging Centre) at the Izaak Walton Killam Health Centre in Halifax, and was partially funded by TREVENTIS™ Corporation of which Dr. Darvesh is a scientific co-founder. SPECT imaging provides 3D information with a high degree of sensitivity and specificity for detecting the presence of a particular radiolabeled enzyme, in this case the BChE (butyrylcholinesterase) enzyme. Prior research has shown that elevated BChE expression levels are associated with abnormal ß-amyloid (Aß) plaques in the brains of Alzheimer’s patients. The novel molecular label, TRV6001, was synthesized and determined to bind to BChE with high specificity before being injected into 5XFAD mouse models of Alzheimer’s Disease. TRV6001 is still under development and has not yet been shown to be safe or effective in humans. “SPECT imaging has provided us the first direct in vivo evidence that the TRV6001 label can cross the blood-brain barrier and actually exhibits higher retention in the brains of AD mice (whose BChE level is markedly elevated) than in normal control brains,” said lead author Drew DeBay, Ph.D. candidate at the Department of Medical Neuroscience, Dalhousie University. In addition, the retention in BChE-associated brain structures was shown to closely follow the known histochemical distribution of BChE that has been previously established in AD mouse models. “Up to now there have been many false-positives,” said Dr. Sultan Darvesh, FRCPC, Professor at the Department of Medical Neuroscience, Dalhousie University. “Previous labels were able to bind to Aß plaque–but Aß is also present in cognitively normal people. BChE, which we are detecting, is notably absent in the non-Alzheimer’s brain.” “Alzheimer’s disease affects so many people and causes such pain and suffering for individuals and their families,” said George Abe, CEO of Cubresa. “We’re pleased to know that our SPECT scanner has contributed to a big step towards developing effective treatments and monitoring their effect.” The research was presented this year at the Alzheimer's Association International Conference® (AAIC®), the world's largest forum for the dementia research community, in Toronto, Canada. Detailed caption for associated image: Representative WT (wild-type, left column) and 5XFAD (Alzheimer’s model, right column) brains at the mid-coronal level. Row A: Histochemical staining of BChE, revealing marked elevation of BChE in AD, notably in the cerebral cortex. C = cerebral cortex, H = hippocampus, BG = basal ganglia, Th = thalamus, A = amygdala. Scale bar = 1mm. Row B: CT with co-registered MR at the same level as Row A. Row C: SPECT images acquired at 4 mins post-injection with co-registered CT/MR and ROIs. Marked retention in the cerebral cortex is evident in the 5XFAD brain compared to the WT brain and to a lesser extent in amygdala, hippocampus, basal ganglia and thalamus. Images courtesy of the Darvesh group and BIOTIC. About Cubresa Inc. Cubresa is a medical imaging company that develops and markets nuclear imaging systems that enable researchers at leading universities, hospitals and pharmaceutical companies to non-invasively visualize and measure biochemical processes at the molecular level. Applications for Cubresa’s products include preclinical drug development, disease research in oncology, neurology, and cardiology, as well as clinical diagnostics. Cubresa has operations in Boston, Massachusetts and Winnipeg, Manitoba. Visit http://www.cubresa.com for more information. About Dalhousie University Dalhousie University is internationally known as one of North America’s most welcoming universities. Founded in 1818, Dalhousie is one of Canada’s oldest universities, attracting more than 18,500 students from around the world. Located on Canada’s East Coast, the university blends world-class academic programs with leading-edge research. Visit http://www.dal.ca for more information. About Mount Saint Vincent University Recognized as a leader in distance and experiential learning, and based on a strong tradition of social responsibility, Mount Saint Vincent University takes a personalized approach to education to nurture socially responsible global citizens. Founded in 1873, the Mount has been nationally recognized for having one of the lowest student-to-professor ratios, for providing students early access to valuable research opportunities, for its legacy in the advancement of women, and for facilitating critical advancements in food security, healthy aging, literacy, and childhood development. Visit http://www.msvu.ca for more information. About Izaak Walton Killam Health Centre and the Biomedical Translational Imaging Centre The IWK Health Centre is the Maritime region's leading health care and research centre dedicated to the well-being of women, children, youth and families. In addition to providing highly specialized and complex care, the IWK provides certain primary care services and is a strong advocate for the health of families. The IWK is a global leader in research and knowledge sharing, and a partner in educating the next generation of health professionals. As part of the IWK Health Centre, the Biomedical Translational Imaging Centre (BIOTIC) has an explicit mandate to translate medical science innovations with industry partners using clinical and preclinical imaging tools to produce next-generation healthcare advances. Visit http://www.iwk.nshealth.ca for more information. About TREVENTIS™ Corporation TREVENTIS is headquartered in Southeastern Pennsylvania and has research operations in Halifax and Toronto, Canada. The company is focused on the discovery and development of disease-modifying small molecule drugs for a variety of dementias including Alzheimer’s. In addition to its therapeutic programs, TREVENTIS has a novel approach to the development of diagnostics for early diagnosis and monitoring treatment effects in Alzheimer’s disease. Visit http://www.treventis.com for more information.
Karnovsky N.J.,Pomona College |
Hobson K.A.,Environment Canada |
Iverson S.J.,Dalhousie University
Marine Ecology Progress Series | Year: 2012
Understanding seabird marine habitat affinities, at-sea behavior, variability in reproductive success, migratory patterns, phenology, and other life history traits depends primarily on knowledge of the prey that they consume. Traditionally, estimating diets has been done through classification and enumeration of prey remains found in stomach contents of seabirds collected at sea, as well as chick meals, pellets, and feces collected at breeding colonies. These techniques have the advantage of high taxonomic resolution of prey, but suffer from biases due to the under - estimation of soft-bodied or small prey that are digested completely and overestimation of prey with durable parts that are retained for long periods of time. Recent innovations in 2 biochemical assays of seabird tissues - stable isotope and fatty acid analyses - have greatly expanded knowledge of seabird diets and have advanced our understanding of the ways in which seabirds can indicate inter- seasonal, annual, decadal, and longer shifts in oceanographic conditions over varying spatial scales. Advances in statistical approaches to these data have provided new ways in which prey can be identified and quantified. When applied in combination, these 3 techniques (traditional diet sampling, and stable isotope and fatty acid analyses) have the potential to reveal pathways of energy flux across marine ecosystems and to provide new insight into marine ecosystem dynamics. We review the basic principles of these approaches to determining seabird diet and emphasize the need for more formal conceptual and statistical integration of methods to advance this field. © Inter-Research 2012.
Braid J.A.,Dalhousie University |
Murphy J.B.,University of Saint Francis Xavier of Bolivia |
Quesada C.,Instituto Geologico Y Minero Of Espana
Gondwana Research | Year: 2010
Models concerning the tectonic evolution of accretionary complexes typically relate outcrop-scale to plate-scale multiphase deformation as a smooth variation of strain on all scales. However, at oblique convergent margins, regional scale brittle faults in the shallow crust are commonly parallel to the main orogenic grain. These faults impose a strong structural anisotropy and can subsequently control deformation at subordinate scales. As a result, finite strain in each domain may not record local kinematics consistent with the overall orogenic-scale motion implying that structural data must be analyzed selectively from a large area in order to relate outcrop-scale kinematics to global plate-scale dynamics. Field mapping and preliminary structural analysis of the Late Devonian Pulo do Lobo (PDL) Formation, and suspect "exotic" South Portuguese Zone (SPZ) in southern Iberia indicate tectonic juxtaposition of diverse deposits such as foreland basin flysch, sedimentary and tectonic mélange, and passive margin sediments showing an overall geometry consistent with an accretionary wedge setting. Variations in finite strain, lithology and regional structure were used as proxies for defining tectonic domains for structural analysis. Numerous local kinematic indicators within the PDL suggest a complex regional deformation with several enigmatic features that can be explained by sequential compartmentalization of strain during the development of the imbricate stack followed by late-stage bulk strain imposed across the entire complex. Structural data produced by local strain partitioning reveals kinematic indicators, which contradict the overall regional structural style (e.g. spatial juxtaposition of sinistral and dextral fabrics). When viewed at larger scales (i.e. regional scale), however, these data indicate that significant sinistral strike-slip movement occurred in conjunction with both an extension and shortening. Outcrop-scale deformation in polydeformed domains is controlled by local conditions resulting from brittle deformation coeval with orogenic-scale bulk strain. The entire Pulo do Lobo Zone is dominated by a pervasive late-stage vertical to sub-vertical E-W cleavage axial planar to chevron folds which overprint earlier deformation in the older passive margin units. This overprinting suggests that in the late stages of the evolution of the accretionary complex, bulk strain was imposed over the entire complex as a result of internal locking of the accretionary complex and reduced strain rates during the waning stages of collision between Gondwana and Laurussia. Stereographic analysis of fabric elements from each distinct tectonic domain, together with regional geological constraints, support this hypothesis and are indicative of progressive deformation imposed on the PDL during the Variscan Orogeny. Crown Copyright © 2009.
Uher R.,King's College London |
Uher R.,Dalhousie University |
Rutter M.,King's College London
World Psychiatry | Year: 2012
Current classification of eating disorders is failing to classify most clinical presentations; ignores continuities between child, adolescent and adult manifestations; and requires frequent changes of diagnosis to accommodate the natural course of these disorders. The classification is divorced from clinical practice, and investigators of clinical trials have felt compelled to introduce unsystematic modifications. Classification of feeding and eating disorders in ICD-11 requires substantial changes to remediate the shortcomings. We review evidence on the developmental and cross-cultural differences and continuities, course and distinctive features of feeding and eating disorders. We make the following recommendations: a) feeding and eating disorders should be merged into a single grouping with categories applicable across age groups; b) the category of anorexia nervosa should be broadened through dropping the requirement for amenorrhoea, extending the weight criterion to any significant underweight, and extending the cognitive criterion to include developmentally and culturally relevant presentations; c) a severity qualifier "with dangerously low body weight" should distinguish the severe cases of anorexia nervosa that carry the riskiest prognosis; d) bulimia nervosa should be extended to include subjective binge eating; e) binge eating disorder should be included as a specific category defined by subjective or objective binge eating in the absence of regular compensatory behaviour; f) combined eating disorder should classify subjects who sequentially or concurrently fulfil criteria for both anorexia and bulimia nervosa; g) avoidant/restrictive food intake disorder should classify restricted food intake in children or adults that is not accompanied by body weight and shape related psychopathology; h) a uniform minimum duration criterion of four weeks should apply.
Mora C.,Dalhousie University |
Mora C.,University of Hawaii at Manoa |
Sale P.F.,Environment Canada
Marine Ecology Progress Series | Year: 2011
A leading strategy in international efforts to reverse ongoing losses in biodiversity is the use of protected areas. We use a broad range of data and a review of the literature to show that the effectiveness of existing, and the current pace of the establishment of new, protected areas will not be able to overcome current trends of loss of marine and terrestrial biodiversity. Despite local successes of well-designed and well-managed protected areas proving effective in stemming biodiversity loss, there are significant shortcomings in the usual process of implementation of protected areas that preclude relying on them as a global solution to this problem. The shortcomings include technical problems associated with large gaps in the coverage of critical ecological processes related to individual home ranges and propagule dispersal, and the overall failure of such areas to protect against the broad range of threats affecting ecosystems. Practical issues include budget constraints, conflicts with human development, and a growing human population that will increase not only the extent of anthropogenic stressors but the difficulty in successfully enforcing protected areas. While efforts towards improving and increasing the number and/or size of protected areas must continue, there is a clear and urgent need for the development of additional solutions for biodiversity loss, particularly ones that stabilize the size of the world's human population and our ecological demands on biodiversity. © Inter-Research 2011.
Lynch M.E.,Dalhousie University |
Lynch M.E.,Pain Management Unit |
Ware M.A.,McGill University
Journal of Neuroimmune Pharmacology | Year: 2015
An updated systematic review of randomized controlled trials examining cannabinoids in the treatment of chronic non-cancer pain was conducted according to PRISMA guidelines for systematic reviews reporting on health care outcomes. Eleven trials published since our last review met inclusion criteria. The quality of the trials was excellent. Seven of the trials demonstrated a significant analgesic effect. Several trials also demonstrated improvement in secondary outcomes (e.g., sleep, muscle stiffness and spasticity). Adverse effects most frequently reported such as fatigue and dizziness were mild to moderate in severity and generally well tolerated. This review adds further support that currently available cannabinoids are safe, modestly effective analgesics that provide a reasonable therapeutic option in the management of chronic non-cancer pain. © 2015, Springer Science+Business Media New York.
Uher R.,Dalhousie University |
Uher R.,King's College London
Frontiers in Psychiatry | Year: 2014
Severe mental illness (SMI) is a broad category that includes schizophrenia, bipolar disorder, and severe depression. Both genetic disposition and environmental exposures play important roles in the development of SMI. Multiple lines of evidence suggest that the roles of genetic and environmental factors depend on each other. Gene-environment interactions may underlie the paradox of strong environmental factors for highly heritable disorders, the low estimates of shared environmental influences in twin studies of SMI, and the heritability gap between twin and molecular heritability estimates. Sons and daughters of parents with SMI are more vulnerable to the effects of prenatal and postnatal environmental exposures, suggesting that the expression of genetic liability depends on environment. In the last decade, gene-environment interactions involving specific molecular variants in candidate genes have been identified. Replicated findings include an interaction between a polymorphism in the AKT1 gene and cannabis use in the development of psychosis and an interaction between the length polymorphism of the serotonin transporter gene and childhood maltreatment in the development of persistent depressive disorder. Bipolar disorder has been underinvestigated, with only a single study showing an interaction between a functional polymorphism in the BDNF gene and stressful life events triggering bipolar depressive episodes. The first systematic search for gene-environment interactions has found that a polymorphism in CTNNA3 may sensitize the developing brain to the pathogenic effect of cytomegalovirus in utero, leading to schizophrenia in adulthood. Strategies for genome-wide investigations will likely include coordination between epidemiological and genetic research efforts, systematic assessment of multiple environmental factors in large samples, and prioritization of genetic variants. © 2007 - 2014 Frontiers Media S.A.
Hajek T.,Dalhousie University |
Hajek T.,National Institute of Mental Health |
Weiner M.W.,University of California at San Francisco
Current Alzheimer Research | Year: 2016
Background: There is a growing body of pre-clinical evidence suggesting that lithium (Li) may protect neurons from a range of neurotoxic insults, hence the term neuroprotective effects. Does Li have similar effects also in human subjects? Methods: We reviewed the neuroimaging literature investigating the association between Li treatment and brain structure. Results: There is level I evidence for positive association between Li treatment and brain grey matter volume, which is one of the most replicated neuroimaging findings. It has been reported in the majority of cross sectional studies, all 8 prospective studies, including a randomized controlled trial as well as in 2 meta-analyses and one mega-analysis. The association between Li treatment and grey matter volume occurs regardless of mood state, diagnostic subtype, presence or absence of concomitant medications. It was documented in multiple brain regions, including hippocampus, amygdala, anterior cingulate, subgenual cingulate, inferior frontal gyrus, postcentral gyrus, habenula. Conclusion: Although some methodological and clinical issues complicate the interpretation of findings, there is robust and highly replicated level 1 evidence for positive association between Li treatment and grey matter volumes. These "neuroprotective" effects of Li have been shown even in healthy subjects and appear independent of prophylactic treatment response. Consequently, Li might help maintain brain health even in patients without bipolar disorders and could possibly demonstrate diseasemodifying properties in neurodegenerative disorders. © 2016 Bentham Science Publishers.
Uher R.,Dalhousie University |
Uher R.,King's College London
Social Psychiatry and Psychiatric Epidemiology | Year: 2014
A decade of research has demonstrated the explanatory potential of interplay between genetic variants and environmental factors in the development of common mental disorders. Initial findings have undergone tests of replicability and specificity. Some gene-environment interactions have been confirmed, some have not replicated and yet other turned out to be more specific than initially thought. Specific and complementary roles of genetic factors have been delineated: a common functional length polymorphism in the serotonin transporter gene (5-HTTLPR) moderated the effect of childhood maltreatment on chronic depression in adulthood, but did not substantially influence the effects of adult stressful life events on the onset of new depressive episodes; in contrast, a common functional polymorphism in the brain-derived neurotrophic factor gene (BDNF) moderated the effect of stressful life events in adulthood in triggering new depressive episodes, but did not influence the effects of childhood maltreatment. Molecular mechanisms underlying gene-environment interactions are being uncovered, including DNA methylation and other epigenetic modifications. New gene-environment interactions continue to be reported, still largely from hypothesis-driven research. Statistical and biological prioritization strategies are proposed to facilitate a systematic discovery of novel gene-environment interactions in genome-wide analyses. © 2013 Springer-Verlag Berlin Heidelberg.
Gomez-Ullate D.,Complutense University of Madrid |
Kamran N.,McGill University |
Milson R.,Dalhousie University
Foundations of Computational Mathematics | Year: 2013
Exceptional orthogonal polynomial systems (X-OPSs) arise as eigenfunctions of Sturm-Liouville problems, but without the assumption that an eigenpolynomial of every degree is present. In this sense, they generalize the classical families of Hermite, Laguerre, and Jacobi, and include as a special case the family of CPRS orthogonal polynomials introduced by Cariñena et al. (J. Phys. A 41:085301, 2008). We formulate the following conjecture: every exceptional orthogonal polynomial system is related to a classical system by a Darboux-Crum transformation. We give a proof of this conjecture for codimension 2 exceptional orthogonal polynomials (X2-OPs). As a by-product of this analysis, we prove a Bochner-type theorem classifying all possible X2-OPSs. The classification includes all cases known to date plus some new examples of X2-Laguerre and X2-Jacobi polynomials. © 2012 SFoCM.
Coley A.,Dalhousie University |
Hervik S.,University of Stavanger
Classical and Quantum Gravity | Year: 2010
We develop the bivector formalism in higher dimensional Lorentzian spacetimes. We define the Weyl bivector operator in a manner consistent with its boost-weight decomposition. We then algebraically classify the Weyl tensor, which gives rise to a refinement in dimensions higher than four of the usual alignment (boost-weight) classification, in terms of the irreducible representations of the spins. We are consequently able to define a number of new algebraically special cases. In particular, the classification in five dimensions is discussed in some detail. In addition, utilizing the (refined) algebraic classification, we are able to prove some interesting results when the Weyl tensor has (additional) symmetries. © 2010 IOP Publishing Ltd.
Hervik S.,University of Stavanger |
Coley A.,Dalhousie University
Classical and Quantum Gravity | Year: 2010
We continue the study of the question of when a pseudo-Riemannain manifold can be locally characterized by its scalar polynomial curvature invariants (constructed from the Riemann tensor and its covariant derivatives). We make further use of the alignment theory and the bivector form of the Weyl operator in higher dimensions and introduce the important notions of diagonalizability and (complex) analytic metric extension. We show that if there exists an analytic metric extension of an arbitrary dimensional space of any signature to a Riemannian space (of Euclidean signature), then that space is characterized by its scalar curvature invariants. In particular, we discuss the Lorentzian case and the neutral signature case in four dimensions in more detail. © 2010 IOP Publishing Ltd.
Arnold D.V.,Dalhousie University |
Hansen N.,University Paris - Sud
GECCO'12 - Proceedings of the 14th International Conference on Genetic and Evolutionary Computation | Year: 2012
This paper introduces a novel constraint handling approach for covariance matrix adaptation evolution strategies (CMA-ES). The key idea is to approximate the directions of the local normal vectors of the constraint boundaries by accumulating steps that violate the respective constraints, and to then reduce variances of the mutation distribution in those directions. The resulting strategy is able to approach the boundary of the feasible region without being impeded in its ability to search in directions tangential to the boundaries. The approach is implemented in the (1+1)-CMA-ES and evaluated numerically on several test problems. The results compare very favourably with data for other constraint handling approaches applied to unimodal test problems that can be found in the literature. © 2012 ACM.
Agency: European Commission | Branch: FP7 | Program: CP-IP | Phase: ENV.2010.1.1.3-1 | Award Amount: 9.56M | Year: 2011
CARBOCHANGE will provide the best possible process-based quantification of net ocean carbon uptake under changing climate conditions using past and present ocean carbon cycle changes for a better prediction of future ocean carbon uptake. We will improve the quantitative understanding of key biogeochemical and physical processes through a combination of observations and models. We will upscale new process understanding to large-scale integrative feedbacks of the ocean carbon cycle to climate change and rising carbon dioxide concentrations. We will quantify the vulnerability of the ocean carbon sources and sinks in a probabilistic sense using cutting edge coupled Earth system models under a spectrum of emission scenarios including climate stabilisation scenarios as required for the 5th IPCC assessment report. The drivers for the vulnerabilities will be identified. The most actual observations of the changing ocean carbon sink will be systematically integrated with the newest ocean carbon models, a coupled land-ocean model, an Earth system model of intermediate complexity, and fully fledged Earth system models through a spectrum of data assimilation methods as well as advanced performance assessment tools. Results will be optimal process descriptions and most realistic error margins for future ocean carbon uptake quantifications with models under the presently available observational evidence. The project will deliver calibrated future evolutions of ocean pH and carbonate saturation as required by the research community on ocean acidification in the EU project EPOCA and further projects in this field. The time history of atmosphere-ocean carbon fluxes past, present, and future will be synthesised globally as well as regionally for the transcontinental RECCAP project. Observations and model results will merge into GEOSS/GEO through links with the European coordination action COCOS and will prepare the marine branch of the European Research Infrastructure ICOS.
Rasic D.,Dalhousie University |
Hajek T.,Dalhousie University |
Hajek T.,Charles University |
Alda M.,Dalhousie University |
And 2 more authors.
Schizophrenia Bulletin | Year: 2014
Objective: Offspring of parents with severe mental illness (SMI; schizophrenia, bipolar disorder, major depressive disorder) are at an increased risk of developing mental illness. We aimed to quantify the risk of mental disorders in offspring and determine whether increased risk extends beyond the disorder present in the parent. Method: Meta-analyses of absolute and relative rates of mental disorders in offspring of parents with schizophrenia, bipolar disorder, or depression in family high-risk studies published by December 2012. Results: We included 33 studies with 3863 offspring of parents with SMI and 3158 control offspring. Offspring of parents with SMI had a 32% probability of developing SMI (95% CI: 24%-42%) by adulthood (age >20). This risk was more than twice that of control offspring (risk ratio [RR] 2.52; 95% CI 2.08-3.06, P <. 001). High-risk offspring had a significantly increased rate of the disorder present in the parent (RR = 3.59; 95% CI: 2.57-5.02, P <. 001) and of other types of SMI (RR = 1.92; 95% CI: 1.48-2.49, P <. 001). The risk of mood disorders was significantly increased among offspring of parents with schizophrenia (RR = 1.62; 95% CI: 1.02-2.58; P =. 042). The risk of schizophrenia was significantly increased in offspring of parents with bipolar disorder (RR = 6.42; 95% CI: 2.20-18.78, P <. 001) but not among offspring of parents with depression (RR = 1.71; 95% CI: 0.19-15.16, P =. 631). Conclusions: Offspring of parents with SMI are at increased risk for a range of psychiatric disorders and one third of them may develop a SMI by early adulthood. © 2013 The Author.
News Article | November 22, 2016
HALIFAX, NOVA SCOTIA--(Marketwired - Nov. 22, 2016) - Ucore Rare Metals Inc. (TSX VENTURE:UCU)(OTCQX:UURAF) ("Ucore" or the "Company") is pleased to announce recent appointments to the Company's Board of Directors. Mr. Patrick Ryan has been appointed as the Chairman of the Board of Directors. He is the founder of Neocon International ("Neocon"), a multi-million dollar OEM design and lean manufacturing company serving international leading automotive enterprises such as Toyota, Nissan and General Motors. From its North American base of operations, Neocon serves as a Tier One automotive supplier, focusing on the development and manufacture of innovative factory-installed vehicle components, using light weight and high strength materials, OEM green initiatives, and patented processes designed to reduce output cycle times and unit cost. Since Neocon's inception in 1993, Mr. Ryan has been the company's strategic architect, responsible for sales growth and capital acquisitions, while directing a team of R&D engineers and promoting stringent production standards. Under Mr. Ryan's direction, Neocon was acquired in 2002 by Exco Technologies, Ltd., a publically traded TSX company. Prior to founding Neocon, Mr. Ryan held positions as V.P. Operations for Plastics Maritime Ltd. and Product Design Engineer for T.S. Simms and Company. He mentors MBA students and graduating design engineers from Dalhousie University from which he holds a Bachelor of Engineering degree. He is the recipient of the APENS Award from the Association of Professional Engineers of Nova Scotia as "the most likely to serve society in an ethical manner". Mr. Steven Meister has been appointed as a member of the Ucore Board of Directors. Mr. Meister is Director of Client Development and Delivery with Williams Engineering Canada Ltd. As a member of the senior leadership team at Williams, his key responsibilities include managing the Northern Canada Operating Region, as well as directing business development and project management. Mr. Meister has over 25 years of management and business development. Since 1995, he has been strategically involved in business initiatives throughout the mining, oil and gas, and utilities industries across northern and western Canada. Previously, Mr. Meister was employed by Stantec (formally Jacques Whitford Stantec AXYS) as Operations Manager for Northern Canada, and Business Development Manager for ARDICOM, an aboriginal partnership between Northern Aboriginal Services Company (NASCo), Arctic Cooperatives Limited (ACL) and Northwestel. He has also worked with numerous communities and key stakeholders, including First Nation businesses and regional organizations. "We're delighted to announce these appointments to the Ucore Board," said Jim McKenzie, President and CEO of Ucore. "Tier One companies are the most technically-capable suppliers in the automotive manufacturing chain. As chief architect of Neocon, Mr. Ryan brings a vast skill set to Ucore as we transition to a revenue business model with energy metal production. The end customers of our Strategic Metals Complex will be tier one, two and three in a sophisticated supply chain, all of which Mr. Ryan is very attuned to serving, including such Global 1000 customers as General Motors, Nissan and Toyota among others. Mr. Meister is a specialist in senior business development, targeting leading companies in the mining, O&G, and utilities sectors. Together, these specialists make for an exceptional complement to Ucore's governance, management and advisory resources." The Company notes that Mr. Jos De Smedt has resigned from the Board to pursue other business interests, remaining with Ucore in a consulting and advisory capacity for an initial term of 12 months. The Company wishes to thank Mr. De Smedt for his exceptional contribution to the Board over his many years with the Company. The Company additionally reports that 300,000 options have been granted to a Director of the Company, subject to the approval of the TSX Venture Exchange. The options are exercisable at a price of $0.31 and will expire on November 19, 2021. One third of the options will vest after six months, with one third vesting every six months thereafter until fully vested. Ucore Rare Metals, one of PwC Canada's top junior mining companies for 2016, is a development-phase company focused on rare metals resources, extraction and beneficiation technologies with near term potential for production, growth and scalability. On March 3, 2015, Ucore announced the right to acquire a controlling ownership interest in the exclusive rights to IBC SuperLig® technology for rare earths and multi-metallic tailings processing applications in North America and associated world markets. The Company has a 100% ownership stake in the Bokan project. On March 31, 2014, Ucore announced the unanimous support of the Alaska State Legislature for the investment of up to USD $145 Million in the Bokan project at the discretion of the Alaska Import Development and Export Agency ("AIDEA"). For further information, please visit http://www.ucore.com. Neither the TSX Venture Exchange nor its Regulation Services Provider (as that term is defined by the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this release.
News Article | April 15, 2016
Road rage may have played a role in the shooting death of former NFL player Will Smith in New Orleans over the weekend, police have said. Whether or not road rage is implicated, the incident highlights the real threat of what seem to be driver tantrums. And, according to scientists, freak-outs on the road can be considered a mental disorder, or at the very least, may stem from brain abnormalities. "I would be surprised if the person who killed Smith didn't have an anger problem," University of Chicago psychiatry professor Dr. Emil Coccaro told Live Science, referring to the driver who rear-ended Smith's car. [Hypersex to Hoarding: 7 New Psychological Disorders] After the collision, the two men pulled over and exchanged words, during which time the other driver pulled out a handgun and shot both Smith and his wife, injuring her and killing Smith at the scene, according to a release by the New Orleans Police Department. Police are investigating the possibility that road rage, among other potential causes, was a factor in the shooting, according to the Washington Post. Coccaro and other psychologists consider road rage a manifestation of a psychiatric disorder called intermittent explosive disorder (IED), which is essentially a problem of "recurrent, problematic, aggressive, impulsive outbursts," Coccaro said. Though scientists can't say what proportion of road rage is related to IED, road rage is one type of outburst that people with IED have, he said. More specifically, according to the current (fifth) edition of the Diagnostic and Statistical Manual of Mental Disorders, IED can involve either frequent, low-intensity outbursts or less frequent but more destructive ones (three or more episodes within the course of a year that to lead to destruction of property or bodily harm). Most people with IED, however, experience both kinds of outbursts, Coccaro said. What's the line between an angry outburst while driving and a psychiatric disorder? In addition to the two types of outbursts, IED is associated with aggression that is disproportionate to the situation; it isn't premeditated; and it's not related to substance abuse or another mental disorder, Coccaro said. Additionally, the outbursts "have to get [the person with IED] into trouble. They have to cause them distress, or they have to get them into difficulty with others, either in their relationships or at work. Typically, it's with relationships," Coccaro said. [Understanding the 10 Most Destructive Human Behaviors] People with IED often "have trouble understanding what's happening in their interactions with other people, particularly when those interactions are ambivalent," Coccaro said. They are more likely to misinterpret people's actions as threats and respond with aggression. Interpersonal interactions tend to trigger outbursts in people with IED, he said. As for why some people have "shorter fuses" than others, that boils down to biology, Coccaro said. People with IED tend to have higher levels of proteins that are linked to inflammation, according to a 2013 study led by Coccaro and published in the journal JAMA Psychiatry. It's unknown if inflammation leads to aggression, though animal research suggests that it might, Coccaro said. Brain abnormalities also factor into aggression, he said. In people with aggression problems like IED, "the frontal areas of the brain function less well, and they're the brakes of the system," said Coccaro. The accelerator in this aggression system would be the lower areas of the brain, such as the amygdala, he added. "That tends to be hyper-responsive to threat stimuli." Research has shown that people with IED tend to have less gray matter in the cortical limbic regions — their "brakes" are less well-endowed, Coccaro said. Coccaro noted that the kinds of correlations he has observed among aggression and other factors also hold for people who do not have IED. In other words, the same correlations, say between gray matter levels and aggression, are seen when people have less intense outbursts that wouldn't be considered IED. Rather, IED is aggression at a level deemed clinically significant. "When you get up to high levels of aggression, it becomes its own disorder," Coccaro said. Sometimes an accident can result in an abnormally aggressive driver. For instance, people who have had a traumatic brain injury (TBI) are about four times as likely to engage in driver aggression as those who have not experienced such an injury, according to a study of Ontario adult drivers published last year in the journal Accident Analysis and Prevention. According to the same study, TBI survivors were also more likely to have been involved in vehicle collisions. [The Odds of Dying] "When we look at the large proportion of adult drivers with a history of traumatic brain injury" — about 17 percent in the Ontario study — "it's very possible that these individuals may account for a great proportion of [or] burden of all traffic-safety problems," said study author Gabriela Ilie, now a faculty member at Dalhousie University, in Nova Scotia. External factors also play a role. Motorists who drive with guns in the car are significantly more likely to engage in aggressive driving behavior (such as making obscene gestures or aggressively following another vehicle), according to two studies led by the Harvard Injury Control Research Center of the university's School of Public Health. "We don't know whether having a gun in the car changes people's behavior, or if they tended to be more aggressive to start with," David Hemenway, director of the center and a co-author on both studies, told Live Science. "What we would like is that people driving around with guns were the most calm and least aggressive motorists," he said. "The opposite seems to be the case." "Add to that the fact that violent behavior with a gun is much more likely to prove lethal than violent behavior without a gun, [and] what we can say is that Will Smith stood a much better chance of being alive today if the rageful encounter on the road did not involve a gun," added center co-director and study author Dr. Matthew Miller. To clear the roads of such harmful tantrums, Coccaro suggested paying some heed to the actual perpetrators. "People get very concerned about victims of violence. They have no concern for the perpetrators of violence, because they're just seen as bad people," Coccaro said. "If we don't do something to understand and help the people who are more aggressive than the rest of us, we're still going to have victims." Current treatments that help people with IED include serotonin modulators, such as selective serotonin re-uptake inhibitors (anti-anxiety drugs), which could raise the emotional threshold for an outburst. Cognitive behavioral therapy might also help people better control their reactions in potentially triggering situations, Coccaro said. Copyright 2016 LiveScience, a Purch company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.
News Article | September 9, 2016
« KLM to operate biofuel flights out of Los Angeles | Main | Gevo to supply Lufthansa with alcohol-to-jet fuel (ATJ) » One pragmatic approach to delivering the high energy-density Li-ion batteries required for longer EV range is to boost the operating voltage of batteries above the current ~4 volts. However, the performance of some higher voltage electrode materials is poor in conventional carbonate-based electrolytes due to increased electrolyte oxidation at high positive potentials, leading to cell failure stemming from gas generation and impedance growth. As a result, successfully operating higher voltage Li-ion cells may require a combination of new electrolyte solvents, electrolyte additives as well as surface coatings. A team at Dalhousie University (Canada) led by Professor Jeff Dahn has explored the impact of different electrolyte solvents and electrolyte additives in high-voltage coated and uncoated NMC442 (LiNi Mn Co O )/graphite cells and compared them head-to-head using an automatic storage system (up to 4.7 V) and automated EIS/cycling measurements (up to 4.5 V). A paper detailing their findings is published in the Journal of Power Sources. The researchers measured voltage drop and impedance growth during cycling experiments as well as gas evolution during both cycling and storage. They also performed long-term cycling experiments (to 4.5 V) to compare the charge-discharge cycling stability of cells containing these electrolyte systems. They used eight electrolyte blends containing different electrolyte solvents and additives in both LaPO -coated and uncoated NMC442/graphite pouch cells. Storage experiments showed that the voltage drop during storage at 4.3 or 4.4 V for both coated and uncoated cells was very similar for the same electrolyte choice. At 4.5 V or above, the LaPO -coated cells had a significantly smaller voltage drop than the uncoated cells except when fluorinated electrolytes were used. Automated charge discharge cycling/impedance spectroscopy testing of cells held at 4.5 V for 24 h every cycle showed that all cells containing ethylene carbonate:ethyl methyl carbonate electrolyte or sulfolane:ethyl methyl carbonate electrolyte exhibited severe capacity fade. By contrast, cells containing fluorinated electrolytes had the best capacity retention and smallest impedance growth during these aggressive cycling/hold tests. Long-term cycling experiments to 4.5 V confirmed that cells containing fluorinated electrolyte had the best cycling performance in the uncoated LiNi Mn Co O /graphite cells while cells containing sulfolane:ethyl methyl carbonate electrolyte had the best cycling performance in coated LiNi Mn Co O /graphite cells. This work was mainly focussed on NMC442/graphite cells charged to high potentials. FEC:TFEC-based electrolytes show promise for cycling at high potential by limiting the impedance growth (although initial impedance is high). However gas evolution at high potentials was still a problem even when gas reducing additives like PES were added. The gassing problem of FEC:TFEC-based electrolytes may be due to the use of large amounts of FEC which is apparently not stable at high temperature and/or high potentials. Alternative solvents are required. We encourage other researchers to assist in the search.
News Article | December 8, 2016
CALGARY, AB --(Marketwired - December 08, 2016) - A collaborative research project involving four universities in Alberta and Atlantic Canada has received major funding to address the issue of pipeline corrosion caused by microbial activity. The federal government announcement was made today by Minister of Science, Kirsty Duncan in Montreal. The $7.8 m comes through the Genome Canada 2015 Large-Scale Applied Research Project Competition (LSARP). It will support Managing Microbial Corrosion in Canadian Offshore and Onshore Oil Production, a four-year research project set to begin in January with an aim to improve pipeline integrity. "This work will definitely help to pinpoint how microbial activity causes corrosion in carbon steel infrastructure and help in its early detection so we can minimize leaks," says Lisa Gieg, an associate professor in the Department of Biological Sciences at the University of Calgary. "It's not just about pipelines, this research will look at all points of contact between oil and steel in extraction, production and processing. This work can help make the industry safer." Gieg is one of three project leaders who include John Wolodko, an associate professor and Alberta Innovates Strategic Chair in Bio and Industrial Materials at the University of Alberta; and Faisal Khan, a professor and the Vale Research Chair of Process Safety and Risk Engineering at Memorial University in St. John's, NL. Also working on the project is Rob Beiko, an associate professor in computer science and Canada Research Chair in Bioinformatics at Dalhousie University in Halifax, N.S., and Dr. Tesfaalem Haile who is a senior corrosion specialist at InnoTech Alberta in Devon, AB. Beiko will be building a database to analyse the microbiology and chemistry lab results, while Haile's team will be working with the University of Alberta to simulate microbial corrosion in the lab and at the pilot-scale. "To some degree, [microbial degradation of pipelines] is akin to a cancer diagnosis and treatment in the medical field," says Wolodko. "While there is significant knowledge and best practices in diagnosing and treating cancer, it is still not completely understood, and significant research is still required to further eliminate its impact to society. "While this problem is complex, this pan-Canadian project brings together research groups from across Canada in different science disciplines to tackle this problem collectively. By bringing this multidisciplinary focus to this problem, it is hoped that this research will lead to a better understanding of the breadth of microbes responsible for microbial corrosion, and will help academia and industry develop improved solutions to rapidly identify and mitigate this form of corrosion globally." While researchers at Memorial University are involved in all stages of the project, Faisal Khan, Head, Department of Process Engineering, and Director, C-RISE, Memorial University, says the focus for Memorial is on how microbes cause corrosion. Khan leads Memorial's multidisciplinary team, which also includes Kelly Hawboldt, Department of Process Engineering, Faculty of Engineering and Applied Science; and Christina Bottaro, Department of Chemistry, Faculty of Science. "We know that microbes cause corrosion, but we are examining how they cause corrosion," said Khan. "We are identifying the chemical source and how it reacts to the surface of the metal to cause corrosion. The risk models that we're developing will link the corrosion process to the outcome. This will be very important for industry when evaluating their level of corrosion intervention and control, and where to focus their resources on corrosion mitigation." Corrosion of steel infrastructure is estimated to cost the oil and gas industry in the range of $3 billion to $7 billion each year in maintenance, repairs and replacement. Microbiologically influenced corrosion is responsible for at least 20 per cent of that cost. The research team will take samples from a wide range of environments including offshore platforms and both upstream pipelines and transmission pipelines, which are all associated with different fluid chemistries and physical characteristics. By using the latest in genomics techniques, the interdisciplinary team will be able to look for trends related to specific microbes and chemistries that lead to microbial corrosion. Ultimately, the project will lead to better predictions of whether microbial corrosion will occur in a given oil and gas operation. All three project leads say the key to success in this project is collaboration. Bringing the experience, skills and expertise from across a range of disciplines and from multiple universities provides the best opportunity to succeed in finding solutions to ensure the safety of pipelines and other oil and gas infrastructure. "Genome Alberta and Genome Atlantic are pleased to be supporting a major study that will develop technologies to proactively detect and pinpoint microbial corrosion in both offshore and onshore oil production," notes David Bailey, President and CEO, Genome Alberta. "These researchers will apply their combined expertise to help address the protection of our natural environment, as well as our growing energy needs," says John Reynolds, acting vice-president (research) at the University of Calgary. "We look forward to working with our research partners and funders who have joined together to support this important work through this Genome Canada award." This grant was one of 13 projects that received funding in an announcement made by the federal government Thursday. Combined with co-funding from the provinces, international organizations and the private sector, the total announcement is worth $110 million. This includes a second project involving a University of Calgary lead to research methods of bioremediation of potential oil spills in the arctic. All the funded projects involve emerging knowledge about genomics (e.g., the genetic makeup of living organisms) to help address challenges in the natural resource and environmental sectors. The project will be managed by Genome Alberta in conjunction with Genome Atlantic, and with an international collaboration of partners that are working together to ensure safer and more secure hydrocarbon energy production: Genome Canada, Alberta Economic Development & Trade, Research & Development Corporation of Newfoundland & Labrador, University of Newcastle upon Tyne, Natural Resources Canada, InnoTech Alberta, VIA University College, DNV-GL Canada, U of C Industrial Research Chair, and in-kind support from a variety of industry partners. About the University of Calgary The University of Calgary is making tremendous progress on its journey to become one of Canada's top five research universities, where research and innovative teaching go hand in hand, and where we fully engage the communities we both serve and lead. This strategy is called Eyes High, inspired by the university's Gaelic motto, which translates as 'I will lift up my eyes.' For more information, visit ucalgary.ca. Stay up to date with University of Calgary news headlines on Twitter @UCalgary. For details on faculties and how to reach experts go to our media centre at ucalgary.ca/news/media. About the University of Alberta The University of Alberta in Edmonton is one of Canada's top teaching and research universities, with an international reputation for excellence across the humanities, sciences, creative arts, business, engineering, and health sciences. Home to 39,000 students and 15,000 faculty and staff, the university has an annual budget of $1.84 billion and attracts nearly $450 million in sponsored research revenue. The U of A offers close to 400 rigorous undergraduate, graduate, and professional programs in 18 faculties on five campuses-including one rural and one francophone campus. The university has more than 275,000 alumni worldwide. The university and its people remain dedicated to the promise made in 1908 by founding president Henry Marshall Tory that knowledge shall be used for "uplifting the whole people." About Memorial University Memorial University is one of the largest universities in Atlantic Canada. As the province's only university, Memorial plays an integral role in the education and cultural life of Newfoundland and Labrador. Offering diverse undergraduate and graduate programs to almost 18,000 students, Memorial provides a distinctive and stimulating environment for learning in St. John's, a safe friendly city with great historic charm, a vibrant cultural life and easy access to a wide range of outdoor activities. About Genome Alberta Genome Alberta is a publicly funded not-for-profit genomics research funding organization based in Calgary, Alberta but leads projects at institutions around the province and participates in a variety of other projects across the country. In partnership with Genome Canada, Industry Canada, and the Province of Alberta, Genome Alberta was established in 2005 to focus on genomics as one of the central components of the Life Sciences Initiative in Alberta, and to help position genomics as a core research effort. For more information on the range of projects led and managed by Genome Alberta, visit http://GenomeAlberta.ca
News Article | November 3, 2016
As the polar ice caps are melting, the Northwest Passage is becoming more navigable – its economic use is within reach. Even the federal government of Germany has the topic on the agenda. "For a country dependent on exports, such as Germany, shorter sea routes are of great importance," says Dr. Wolfgang Koch, Head of Sensor Data and Information Fusion at the Fraunhofer Institute for Communication, Information Processing and Ergonomics FKIE. "Compared to the route between East Asia and Europe via the Suez Canal, the route via the Northwest Passage is about 5,000 nautical miles shorter, which means enormous savings for ship owners," says Koch. This route has been too dangerous, though: There is no reliable information about it. That is what Koch and a German-Canadian research team want to change. In the project PASSAGES (Protection and Advanced Surveillance System for the Artic: Green, Efficient, Secure), they are conducting the preparatory work for safe navigation through the icy waters. This is not an easy task, because the route is challenging not only due to the presence of a number of bays, islands, uncharted shoals and narrows, but also because of drift ice and extreme weather conditions. In addition other vessels sometimes do not record their positions or (in cases like those of illegal fishing vessels) record false positions. The system has to provide reliable information about all of that. The problem: There is little data available, because there is no infrastructure in sensor and communication technology. The entire route is larger than Western Europe and is sparsely populated. Even if there were sufficient data these would have to be processed into information which would be useful for stakeholders such as ship crews. The researchers are addressing all of these difficulties by developing concepts about which technology can gather what information and where and how it can be fused. "The difficulty is to bring together very diverse and inaccurate data in order to provide for instance decision support for ship captains to decide on which route to take when," says Koch. Creating algorithms for the fusion of sensor data is the specialty of the FKIE researchers. The first thing to do, though, is to tap data sources in the harsh climate zone. For example, the Automatic Identification System (AIS) can be used, which reports among other information ships' current position. In addition, there are satellite images (which, however, have the drawback of being incomplete). Even old sonar systems from the Cold War era could be resurrected. However: A high-resolution view by means of which captains could safely pilot through the water does not yet exist. Koch is therefore still hoping for another data provider: the passive radar. This technology uses the electromagnetic pollution from mobile stations near the coast. Receiving stations will tap into this and gain information about ships and ice blocks – their size, position and speed. "In this way, large areas can be monitored," says Koch. Other possibilities are unmanned vehicles that gather information below and above water. Based on the newly gained insights and ideas for such a system, Koch would like to establish an appropriate monitoring and information system: "We hope that our research project will be followed by a development project." The project is supported by the German Federal Ministry for Economic Affairs and Energy (BMWi) as well as the project partners Airbus, exact Earth, and Dalhousie University in Halifax, Canada. An operational system would be a great asset for shipping companies, the Coast Guard and maritime authorities. Even insurance companies are interested in the data. "On this basis, they could calculate premiums for the ships that are to be insured," explains Koch. After the tricky route is made manageable through safe navigation, ship owners would not have to spend so much on insurance coverage. It will take at least a decade until the navigation system is ready to be launched. Over these years, the route will become progressively ice-free and economically navigable for shipping traffic. This will show that the scientific groundwork of today will have been worthwhile. Koch: "As dramatic as global warming is, we try to get at least something positive out of it." Explore further: Bringing the human element to ship design
News Article | November 3, 2016
The Northwest Passage is becoming navigable for longer periods of the year. Ship traffic, however, still bears hazardous risks. A German-Canadian research team co-initiated by Fraunhofer wants to change that. In the project PASSAGES, it is conducting the preparatory work for a safe navigation through the icy waters. As the polar ice caps are melting, the Northwest Passage is becoming more navigable -- its economic use is within reach. Even the federal government of Germany has the topic on the agenda. "For a country dependent on exports, such as Germany, shorter sea routes are of great importance," says Dr. Wolfgang Koch, Head of Sensor Data and Information Fusion at the Fraunhofer Institute for Communication, Information Processing and Ergonomics FKIE. "Compared to the route between East Asia and Europe via the Suez Canal, the route via the Northwest Passage is about 5,000 nautical miles shorter, which means enormous savings for ship owners," says Koch. This route has been too dangerous, though: There is no reliable information about it. That is what Koch and a German-Canadian research team want to change. In the project PASSAGES (Protection and Advanced Surveillance System for the Artic: Green, Efficient, Secure), they are conducting the preparatory work for safe navigation through the icy waters. This is not an easy task, because the route is challenging not only due to the presence of a number of bays, islands, uncharted shoals and narrows, but also because of drift ice and extreme weather conditions. In addition other vessels sometimes do not record their positions or (in cases like those of illegal fishing vessels) record false positions. The system has to provide reliable information about all of that. The problem: There is little data available, because there is no infrastructure in sensor and communication technology. The entire route is larger than Western Europe and is sparsely populated. Even if there were sufficient data these would have to be processed into information which would be useful for stakeholders such as ship crews. The researchers are addressing all of these difficulties by developing concepts about which technology can gather what information and where and how it can be fused. "The difficulty is to bring together very diverse and inaccurate data in order to provide for instance decision support for ship captains to decide on which route to take when," says Koch. Creating algorithms for the fusion of sensor data is the specialty of the FKIE researchers. The first thing to do, though, is to tap data sources in the harsh climate zone. For example, the Automatic Identification System (AIS) can be used, which reports among other information ships' current position. In addition, there are satellite images (which, however, have the drawback of being incomplete). Even old sonar systems from the Cold War era could be resurrected. However: A high-resolution view by means of which captains could safely pilot through the water does not yet exist. Koch is therefore still hoping for another data provider: the passive radar. This technology uses the electromagnetic pollution from mobile stations near the coast. Receiving stations will tap into this and gain information about ships and ice blocks -- their size, position and speed. "In this way, large areas can be monitored," says Koch. Other possibilities are unmanned vehicles that gather information below and above water. Based on the newly gained insights and ideas for such a system, Koch would like to establish an appropriate monitoring and information system: "We hope that our research project will be followed by a development project." The project is supported by the German Federal Ministry for Economic Affairs and Energy (BMWi) as well as the project partners Airbus, exact Earth, and Dalhousie University in Halifax, Canada. An operational system would be a great asset for shipping companies, the Coast Guard and maritime authorities. Even insurance companies are interested in the data. "On this basis, they could calculate premiums for the ships that are to be insured," explains Koch. After the tricky route is made manageable through safe navigation, ship owners would not have to spend so much on insurance coverage. It will take at least a decade until the navigation system is ready to be launched. Over these years, the route will become progressively ice-free and economically navigable for shipping traffic. This will show that the scientific groundwork of today will have been worthwhile. Koch: "As dramatic as global warming is, we try to get at least something positive out of it."
News Article | February 15, 2017
New Rochelle, NY, Feb. 9, 2017 -- A comprehensive collection of articles describing the broad scope and current status of this global effort is published in a special issue of AIDS Research and Human Retroviruses, a peer-reviewed journal from Mary Ann Liebert, Inc., publishers. The third annual Special Issue on HIV Cure Research is available free on the AIDS Research and Human Retroviruses website. Leonardo Calza and coauthors from University of Bologna (Italy), have shown that statins, which are commonly prescribed to lower blood lipid levels, can also significantly reduce the concentration of D-dimer, a marker of coagulation, and of two markers of inflammation known as interleukins (IL-8 and IL-10) in HIV-infected individuals. The anti-inflammatory properties of statins and their potential effects on blood clot formation could help reduce HIV-associated comorbidities such as cardiovascular disease. The researchers present their findings in the article entitled "Significant Decrease in Plasma Levels of D-Dimer, Interleukin-8, and Interleukin-12 After a 12-Month Treatment with Rosuvastatin in HIV-Infected Patients Under Antiretroviral Therapy." In the article "Lower Frailty Is Associated with Successful Cognitive Aging Among Older Adults with HIV," Lindsay Wallace and coauthors from Dalhousie University (Halifax, Canada), University of Modena and Reggio Emilia (Modena, Italy), and University of California San Diego, identified factors associated with better cognitive function among HIV-infected individuals 50 years of age or older being treated with combination antiretroviral therapy. The researchers found that study participants who scored lower on a frailty index were less likely to have neurocognitive impairment. Heather Grome and colleagues from Vanderbilt University Medical Center (Nashville, TN), report on the role that persistent T-cell and macrophage activation in HIV-infected adults on combination antiretroviral therapy may have on the function of arterial blood vessels. The effects of HIV-related chronic immune activation on the arterial lining and vascular smooth muscle may promote the development of atherosclerosis and plaque formation that can lead to cardiovascular disease. The researchers present measures of blood-based inflammatory and immune activation markers and the results of brachial artery flow-mediated dilation on ultrasound in the article entitled "Association of T Cell and Macrophage Activation with Arterial Vascular Health in HIV." "It is becoming clear that although HIV-infected individuals can control the amount of virus in their system with antiviral treatments, there are still negative health consequences that look like premature aging, including cardiovascular disease and cognitive impairment," says Thomas Hope, PhD, Editor-in-Chief of AIDS Research and Human Retroviruses and Professor of Cell and Molecular Biology at Northwestern University, Feinberg School of Medicine (Chicago, IL). "These three papers and others in the Cure issue seek a better understanding of the cause of this accelerated aging. The Calza article suggests that taking statins, which reduce lipid levels, may be an effective treatment to reduce damaging inflammation in HIV-infected individuals taking appropriate antiviral therapy," Research reported by Grome et al. was supported by the National Institutes of Health under Award Numbers K23 100700, K24 AI65298, UL1 RR024975-01, and P30 AI110527. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. AIDS Research and Human Retroviruses, published monthly online with open access options and in print, presents papers, reviews, and case studies documenting the latest developments and research advances in the molecular biology of HIV and SIV and innovative approaches to HIV vaccine and therapeutic drug research, including the development of antiretroviral agents and immune-restorative therapies. Content also explores the molecular and cellular basis of HIV pathogenesis and HIV/HTLV epidemiology. The Journal features rapid publication of emerging sequence information, reports on clinical trials of emerging HIV therapies, and images in HIV research. Tables of content and a sample issue may be viewed on the AIDS Research and Human Retroviruses website. Mary Ann Liebert, Inc., publishers is a privately held, fully integrated media company known for establishing authoritative peer-reviewed journals in many promising areas of science and biomedical research, including AIDS Patient Care and STDs, Viral Immunology, and Journal of Interferon and Cytokine Research. Its biotechnology trade magazine, GEN (Genetic Engineering & Biotechnology News), was the first in its field and is today the industry's most widely read publication worldwide. A complete list of the firm's 80 journals, books, and newsmagazines is available on the Mary Ann Liebert, Inc., publishers website.
Doolittle W.F.,Dalhousie University |
Zhaxybayeva O.,Environmental Proteomics NB Inc.
BioScience | Year: 2010
Metagenomics is a complex of research methodologies aimed at characterizing microbial communities and cataloging microbial diversity and distribution without isolating or culturing organisms. This approach will unavoidably engender new ways of thinking about microbial ecology that supplant the concept of "species." This concept-thanks to comparative-genomicshas in any case become increasingly unsustainable, either as a way of binning diversity or as a biological reality. Communities will become the units of evolutionary and ecological study. Although metagenomic methods will increasingly find uses in protistology and mycology, the emphasis so far has been, and our focus here will be, on prokaryotes (bacteria and archaea). © 2010 by American Institute of Biological Sciences.
Kaiser P.K.,Cleveland Clinic |
Boyer D.S.,University of Southern California |
Cruess A.F.,Dalhousie University |
Slakter J.S.,Vitreous Retina Macula Consultants of New York |
And 2 more authors.
Ophthalmology | Year: 2012
Purpose: To demonstrate noninferiority of ranibizumab in combination with verteporfin photodynamic therapy (PDT) versus ranibizumab monotherapy in patients with subfoveal choroidal neovascularization secondary to age-related macular degeneration (AMD). Design: Prospective, multicenter, double-masked, randomized, phase IIIb clinical trial. Participants: Three hundred twenty-one patients randomized to receive either ranibizumab 0.5 mg monotherapy (n = 112), standard fluence (SF) verteporfin PDT combination therapy (n = 104), or reduced fluence (RF) verteporfin PDT combination therapy (n = 105). Methods: Ranibizumab was administered monthly in the monotherapy group. In both combination therapy groups, ranibizumab was initiated with 3 consecutive monthly injections, followed by retreatment as needed (pro re nata) with monthly monitoring. All patients were evaluated monthly for 12 months. Main Outcome Measures: Mean change in best-corrected visual acuity (BCVA) from baseline at month 12 and proportion of patients randomized to either combination therapy with a ranibizumab treatment-free interval of 3 months or longer. Results: Two hundred eighty-six patients (89.1%) completed the 12-month study. Mean BCVA change at month 12 was +5.3 and +4.4 letters with verteporfin SF (n = 103) or verteporfin RF (n = 105) plus ranibizumab, respectively, compared with +8.1 letters with ranibizumab monotherapy (n = 110; adjusted 97.5% confidence interval [CI], (-7.90 to infinity); P = 0.0666; and 97.5% CI, (-8.51 to infinity); P = 0.1178; for combination regimens vs. monotherapy, respectively). Noninferiority of either combination regimen to monthly ranibizumab monotherapy was not demonstrated (primary end point). A ranibizumab treatment-free interval of 3 months or longer was achieved in 92.6% and 83.5% of the patients randomized to verteporfin SF or verteporfin RF groups, respectively, with a mean of 5.1 and 5.7 ranibizumab injections, respectively, and patients in the ranibizumab monotherapy arm received 10.5 injections. At month 12, mean central retinal thickness decreased by 151.7 μm and 140.9 μm for the verteporfin SF and RF groups, respectively, and by 172.2 μm with ranibizumab monotherapy. Safety and tolerability of all 3 regimens were similar to and consistent with previous studies in neovascular AMD. The number of ocular serious adverse events was low and occurred largely as single cases. Conclusions: Ranibizumab monotherapy or combined with verteporfin PDT improved BCVA at month 12; however, noninferiority (7-letter margin) of combination regimens to ranibizumab monotherapy was not demonstrated. Verteporfin RF did not confer clinical benefits over verteporfin SF. All treatments were well tolerated. Financial Disclosure(s): Proprietary or commercial disclosure may be found after the references. © 2012 American Academy of Ophthalmology.
Maruyama S.,Dalhousie University |
Maruyama S.,Japan National Institute for Basic Biology |
Kim E.,Sackler Institute for Comparative Genomics
Current Biology | Year: 2013
Green algae, land plants, and other photosynthetic eukaryotes possess plastids, such as chloroplasts, which have evolved from cyanobacterial ancestors via endosymbiosis . An early evolutionary merger between heterotrophic eukaryotes and cyanobacteria called primary endosymbiosis gave rise to the first photosynthetic eukaryotes. A series of plastid acquisitions involving engulfment of eukaryotic phototrophs, known as secondary or tertiary endosymbiosis, followed . Through these repeated symbiotic events, photosynthesis spread across a number of eukaryotic lineages [2, 3]. While the origin of eukaryotic photosynthesis was undoubtedly a fundamentally important evolutionary event in Earth's history, without which much of the modern marine phytoplankton would not exist, the cellular processes that shaped this initial plastid genesis remain largely unknown. Here, we report ultrastructural evidence for bacterial phagocytosis in a primary plastid-bearing alga. This mixotrophic green alga utilizes a mouth-like opening, a tubular channel, and a large permanent vacuole to engulf, transport, and digest bacterial cells. This mode of phagocytosis, likely inherited from its plastid-lacking ancestor, differs from those displayed by many other eukaryotes, including animals, amoebas, and ciliates. These results provide insight into the key phagocytosis step during the origin of the first photosynthetic eukaryotes. © 2013 Elsevier Ltd. All rights reserved.
Coll M.,Dalhousie University |
Coll M.,CSIC - Institute of Marine Sciences |
Libralato S.,National Institute of Oceanography and Applied Geophysics - OGS
Fish and Fisheries | Year: 2012
Ecological modelling tools are applied worldwide to support the ecosystem-based approach of marine resources (EAM). In the last decades, numerous applications were attempted in the Mediterranean Sea, mainly using the Ecopath with Ecosim (EwE) tool. These models were used to analyse a variety of complex environmental problems. Many applications analysed the ecosystem impacts of fishing and assessed management options. Other studies dealt with the accumulation of pollution through the food web, the impact of aquaculture or the ecosystem effects of climate change. They contributed to the scientific aspects of an ecosystem-based approach in the region because they integrated human activities within an ecosystem context and evaluated their impact on the marine food web, including environmental factors. These studies also gathered a significant amount of information at an ecosystem level. Thus, in the second part of this review, we used this information to quantify structural and functional traits of Mediterranean marine ecosystems at regional scales as the illustration of further potentialities of EwE for an EAM. Results highlighted differential traits between ecosystem types and a few between basins, which illustrate the environmental heterogeneity of the Mediterranean Sea. Moreover, our analysis evidenced the importance of top predators and small pelagic fish in Mediterranean ecosystems, in addition to the structural role of benthos and plankton organisms. The impact of fishing was high and of a similar intensity in the western, central and eastern regions and showed differences between ecosystem types. The keystone role of species was more prominent in protected environments. © 2011 Blackwell Publishing Ltd.
Keats M.R.,Dalhousie University |
Emery C.A.,University of Calgary |
Finch C.F.,Monash University
Sports Medicine | Year: 2012
Sport and recreational activities are the leading cause of injury in youth, yet there is increasing evidence that many sport-related injuries are preventable. For injury prevention strategies to be effective, individuals must understand, adopt and adhere to the recommended prevention strategy or programme. Despite the recognized importance of a behavioural approach, the inclusion of behavioural change strategies in sport injury prevention has been historically neglected. The purpose of this commentary is to outline the rationale for the inclusion and application of behavioural science in reducing the burden of injury by increasing adherence to proven prevention strategies. In an effort to provide an illustrative example of a behavioural change approach, the authors suggest a specific plan for the implementation of a neuromuscular training strategy to reduce the risk of lower limb injury in youth sport.Given the paucity of evidence in the sport injury prevention setting, and the lack of application of theoretical frameworks to predicting adoption and adherence to injury preventive exercise recommendations in youth sport, data from the related physical activity promotion domain is utilized to describe how sound, theory-based injury prevention exercise interventions in youth may be developed. While the question of how to facilitate behavioural change and optimize adherence to preventive exercise recommendations remains an ongoing challenge, the authors detail several strategies based on two prominent behavioural theories to aid the reader in conceptualizing, designing and implementing effective interventions.Despite the minimal application of behavioural theory within the field of sport injury prevention in youth, behavioural science has the potential to make a significant impact on the understanding and prevention of youth sport injury. Appropriate evaluation of adherence and maintenance components based on models of behavioural change should be a critical component of future injury prevention research and practice. © 2012 Adis Data Information BV. All rights reserved.
Afshani P.,Dalhousie University |
Brodai G.S.,University of Aarhus |
Zeh N.,Dalhousie University
Proceedings of the Annual ACM-SIAM Symposium on Discrete Algorithms | Year: 2011
We study the following problem: Given an array A storing N real numbers, preprocess it to allow fast reporting of the K smallest elements in the subarray A[i,j] in sorted order, for any triple (i,j,K) with 1 ≤ i ≤ j ≤ N and 1 ≤ K ≤ j - i + 1. We are interested in scenarios where the array A is large, necessitating an I/O-efíicient solution. For a parameter / with 1 < / < logm n, we construct a data structure that uses 0((N/f)logmn) space and achieves a query bound of O(logB N + fK/B) I/Os,1 where B is the block size, M is the size of the main memory, n :- N/B, and m := M/B. Our main contribution is to show that this solution is nearly optimal. To be precise, we show that achieving a query bound of O(logαn + fK/B) I/Os, for any constant a, requires Ω(N f-1logMn/log(f-1logMn)) space assuming B = Ω(logN). For M ≥ B1+ε, this is within a log logm n factor of the upper bound. The lower bound assumes indivisibility of records and holds even if we assume K is always set to j - 1 + 1. We also show that it is the requirement that the K smallest elements be reported in sorted order which makes the problem hard. If the K smallest elements in the query range can be reported in any order, then we can obtain a linear-size data structure with a query bound of O(logB N + K/B) I/Os.
Tavori H.,Oregon Health And Science University |
Rashid S.,Dalhousie University |
Fazio S.,Oregon Health And Science University
Atherosclerosis | Year: 2015
Proprotein convertase subtilisin kexin type 9 (PCSK9) is a circulatory ligand that terminates the lifecycle of the low-density lipoprotein (LDL) receptor (LDLR) thus affecting plasma LDL-cholesterol (LDL-C) levels. Recent evidence shows that in addition to the straightforward mechanism of action, there are more complex interactions between PCSK9, LDLR and plasma lipoprotein levels, including: (a) the presence of both parallel and reciprocal regulation of surface LDLR and plasma PCSK9; (b) a correlation between PCSK9 and LDL-C levels dependent not only on the fact that PCSK9 removes hepatic LDLR, but also due to the fact that up to 40% of plasma PCSK9 is physically associated with LDL; and (c) an association between plasma PCSK9 production and the assembly and secretion of triglyceride-rich lipoproteins. The effect of PCSK9 on LDLR is being successfully utilized toward the development of anti-PCSK9 therapies to reduce plasma LDL-C levels. Current biochemical research has uncovered additional mechanisms of action and interacting partners for PCSK9, and this opens the way for a more thorough understanding of the regulation, metabolism, and effects of this interesting protein. © 2014 Elsevier Ireland Ltd.
News Article | November 19, 2015
The team of researchers, led by Chunsheng Wang, an associate professor in UMD's Department of Chemical & Biomolecular Engineering, and Kang Xu, senior research chemist at the Sensor and Electron Devices Directorate of ARL, said their work, published this week in the journal Science, demonstrates a major advance in the long history of water-based (aqueous) batteries by doubling the voltage, or power, of an aqueous battery. The researchers said their technology holds great promise, particularly in applications that involve large energies at kilowatt or megawatt levels, such as electric vehicles, or grid-storage devices for energy harvest systems, and in applications where battery safety and toxicity are primary concerns, such as safe, non-flammable batteries for airplanes, naval vessels or spaceships, and in medical devices like pacemakers. "Through this work we were able to increase the electrochemical window of aqueous electrolyte from less than 1.5 Volts to ~ 3.0 Volts and demonstrated high voltage aqueous full Lithium-ion cell with 2.3 Volts, showing for the first time that aqueous batteries could seriously compete in terms of power and energy density with the non-aqueous lithium-ion batteries that power our mobile, digital lifestyle" said Wang, who also is affiliated with the University of Maryland Energy Research Center and the Maryland NanoCenter. According to Lt. Col. (Retired) Edward Shaffer, who heads the Army Research Laboratory's Energy and Power Division, the significant potential advantages this new approach has over current batteries "could lead to thermally, chemically and environmentally safer batteries carried and worn by soldiers; safe, reduced-footprint energy storage for confined spaces, particularly submarines; and novel hybrid power solutions for military platforms and systems." Researchers Wang, Xu and colleagues found that the key to their breakthrough was the use of a type of water-based electrolyte containing ultrahigh concentrations of a carefully selected Lithium salt. This approach transformed the battery's chemistry, resulting in the formation of a thin protective film on the anode electrode for the very first time in a water-based battery. Known in battery science as a "Solid Electrolyte Interphase (SEI)," such a protective and stabilizing film is essential to the high performance characteristics of state-of-the-art Li-ion batteries. It previously has been achieved only in non-aqueous electrolytes. "What's most important about our work is the breakthrough made at the fundamental level," said UMD Postdoctoral Research Associate Liumin Suo, who is a member of Wang's research group and first author of the Science paper. "Prior to this work no one thought it possible to form SEI in water-based [batteries], but we demonstrated that it can happen." The UMD & ARL team compared the performance of their new "Water-in-Salt" battery with that of other aqueous battery systems. They showed that high stability of other aqueous batteries was achieved only at the expense of voltage and energy density and vice versa. However, the formation of an anode/electrolyte interphase in their "Water-in-Salt" electrolyte allowed them to break this inverse relationship between cycling stability and high voltage and to achieve both simultaneously. "Researchers in the Li-ion battery field have recently found that previously "useless" solvents could be made functional in Li-ion cells through the addition of high concentrations of salts. The work by Suo et al., extends this idea to the case of the solvent, water. By extending the operational voltage window to approximately 3 Volts, it is possible that a new generation of safer and possibly less expensive Li-ion cells could result," said Dalhousie University (Nova Scotia) Professor Jeff Dahn, a leading battery researcher, who was not involved in the study. "Only further R&D; efforts will be able to verify the practicality of this discovery, so prudence is needed in assessing the potential of this, or any basic research advance," said Dahn, the NSERC-3M Canada Industrial Research Chair in Materials for Advanced Batteries. "Our finding opens an entirely new avenue to aqueous electrochemical devices, not only batteries, but also devices like supercapacitors and electroplating devices," said Xu. Explore further: Super stable garnet ceramics may be ideal for high-energy lithium batteries
News Article | April 14, 2016
On Thursday, Canada revealed new legislation aimed at making assisted dying legal. Doctors, pharmacists and nurses will be able to help very sick people to medically end their lives, without worrying that they’ll go to jail for it. Right-to-die advocates say it’s a huge step forward, and that it helps shine light on a practice that has been done behind closed doors, often in less-than-ideal conditions. (Earlier this year, activist John Hofsess wrote about how he’d helped eight people die, including Canadian poet Al Purdy, before travelling to Switzerland for his own assisted death. He published a posthumous account in Toronto Life.) There are lots of questions around how assisted dying will actually work—and one of the most important is how, exactly, we’ll track the people who choose it. What's not up for debate is that collecting every bit of data will be crucially important. Say that lots of patients suffering from one specific condition, like ALS or multiple sclerosis, request an assisted death. It’s important to know that, because it could mean we need to allocate more resources to the disease, for example. Say there are clusters of assisted deaths in certain parts of the country, but not others, or among certain populations. Knowing that will be vital to understanding how Canadians are choosing to die—and to preventing any abuse in the system. The government has proposed to set up mandatory monitoring, but the details have yet to be sorted out. Anyone who participates in an assisted death and fails to report it will face some kind of sanction, according to the scanty details. Canadians are still debating whether to even include “physician-assisted death” on official death certificates, which are used to gather mortality data. A lot of people still don’t like the idea of including a doctor-insisted death on a certificate, partly because there’s still a stigma attached to it. Maybe the patient doesn’t want her family to know. There was also the chance it would affect insurance payouts: some companies won’t pay out if the person died by suicide. In December, Jocelyn Downie and Kacie Oliver of Dalhousie University, in Halifax, published a paper in the Canadian Medical Association Journal arguing that doctor-assisted deaths should be stated on all death certificates, alongside the illness that caused the patient to seek it out. “Death certificates will give access to some information, if it’s done in the way I advocate,” Downie told Motherboard. “But they’re infamously badly completed,” and aren’t always the most reliable documents as a result. For that reason, we need a national tracking system, too. Other places that allow for medically assisted death, like Belgium, the Netherlands, and Oregon, mandate reporting. Oregon, for one, issues an annual report on assisted dying in the state, and according to Downie, the Netherlands commissions a big review on patient outcomes every five years. Ottawa says it’s going to study whether to extend the right to die to those with a mental illness but no physical disability, “mature minors,” and people with an advance directive, although none of these groups are included in legislation for now. As for the doctors, although earlier surveys have found that a majority aren’t keen to help patients die, Dr. Jeff Blackmer of the Canadian Medical Association doesn’t think this will be an issue. “About 30 percent of our members have said that, in theory, they would be interested in participating,” he told Motherboard. “That’s tens of thousands of physicians.” In Oregon, he continued, less than 1 percent of physicians perform assisted deaths. Still, all of this does raise questions about whether people in rural and northern Canada will be able to access an assisted death if they need it—access in remote areas is always a healthcare challenge here—but, according to Blackmer, the fact that nurse practitioners were included in the new legislation should help with access in remote places where no doctors are nearby. Canada is entering brand-new territory. Unless we do a thorough job of tracking patients before and after each assisted death, we won’t know where we’re headed.
News Article | November 22, 2015
Home > Press > UMD & Army researchers discover salty solution to better, safer batteries: Greatest potential uses seen in safety-critical, automotive and grid-storage applications Abstract: A team of researchers from the University of Maryland (UMD) and the U.S. Army Research Laboratory (ARL) have devised a groundbreaking "Water-in-Salt" aqueous Lithium ion battery technology that could provide power, efficiency and longevity comparable to today's Lithium-ion batteries, but without the fire risk, poisonous chemicals and environmental hazards of current Lithium batteries. The team of researchers, led by Chunsheng Wang, an associate professor in UMD's Department of Chemical & Biomolecular Engineering, and Kang Xu, senior research chemist at the Sensor and Electron Devices Directorate of ARL, said their work, published this week in the journal Science, demonstrates a major advance in the long history of water-based (aqueous) batteries by doubling the voltage, or power, of an aqueous battery. The researchers said their technology holds great promise, particularly in applications that involve large energies at kilowatt or megawatt levels, such as electric vehicles, or grid-storage devices for energy harvest systems, and in applications where battery safety and toxicity are primary concerns, such as safe, non-flammable batteries for airplanes, naval vessels or spaceships, and in medical devices like pacemakers. "Through this work we were able to increase the electrochemical window of aqueous electrolyte from less than 1.5 Volts to ~ 3.0 Volts and demonstrated high voltage aqueous full Lithium-ion cell with 2.3 Volts, showing for the first time that aqueous batteries could seriously compete in terms of power and energy density with the non-aqueous lithium-ion batteries that power our mobile, digital lifestyle" said Wang, who also is affiliated with the University of Maryland Energy Research Center and the Maryland NanoCenter. According to Lt. Col. (Retired) Edward Shaffer, who heads the Army Research Laboratory's Energy and Power Division, the significant potential advantages this new approach has over current batteries "could lead to thermally, chemically and environmentally safer batteries carried and worn by soldiers; safe, reduced-footprint energy storage for confined spaces, particularly submarines; and novel hybrid power solutions for military platforms and systems." Researchers Wang, Xu and colleagues found that the key to their breakthrough was the use of a type of water-based electrolyte containing ultrahigh concentrations of a carefully selected Lithium salt. This approach transformed the battery's chemistry, resulting in the formation of a thin protective film on the anode electrode for the very first time in a water-based battery. Known in battery science as a "Solid Electrolyte Interphase (SEI)," such a protective and stabilizing film is essential to the high performance characteristics of state-of-the-art Li-ion batteries. It previously has been achieved only in non-aqueous electrolytes. "What's most important about our work is the breakthrough made at the fundamental level," said UMD Postdoctoral Research Associate Liumin Suo, who is a member of Wang's research group and first author of the Science paper. "Prior to this work no one thought it possible to form SEI in water-based [batteries], but we demonstrated that it can happen." The UMD & ARL team compared the performance of their new "Water-in-Salt" battery with that of other aqueous battery systems. They showed that high stability of other aqueous batteries was achieved only at the expense of voltage and energy density and vice versa. However, the formation of an anode/electrolyte interphase in their "Water-in-Salt" electrolyte allowed them to break this inverse relationship between cycling stability and high voltage and to achieve both simultaneously. "Researchers in the Li-ion battery field have recently found that previously "useless" solvents could be made functional in Li-ion cells through the addition of high concentrations of salts. The work by Suo et al., extends this idea to the case of the solvent, water. By extending the operational voltage window to approximately 3 Volts, it is possible that a new generation of safer and possibly less expensive Li-ion cells could result," said Dalhousie University (Nova Scotia) Professor Jeff Dahn, a leading battery researcher, who was not involved in the study. "Only further R&D efforts will be able to verify the practicality of this discovery, so prudence is needed in assessing the potential of this, or any basic research advance," said Dahn, the NSERC-3M Canada Industrial Research Chair in Materials for Advanced Batteries. "Our finding opens an entirely new avenue to aqueous electrochemical devices, not only batteries, but also devices like supercapacitors and electroplating devices," said Xu. ### This research received funding from the Department of Energy, Advanced Research Projects Agency-Energy (ARPA-E) (DEAR0000389) and support from the Maryland NanoCenter and its Nanoscale Imaging Spectroscopy & Properties Laboratory. This UMD lab is supported in part by the National Science Foundation. Modeling efforts were supported by the ARL Enterprise for Multiscale Research of Materials. "Water-in-Salt" Electrolyte Enables High Voltage Aqueous Li-ion Chemistries Liumin Suo,(1) Oleg Borodin,(2) Tao Gao,(1) Marco Olguin,(2) Janet Ho,(2) Xiulin Fan,(1) Chao Luo,(1) Chunsheng Wang,(1), * Kang Xu (2), * (1)Department of Chemical and Biomolecular Engineering, University of Maryland College Park (2) Electrochemistry Branch, Sensor and Electron Devices Directorate, Power and Energy Division U.S. Army Research Laboratory Adelphi, Maryland For more information, please click If you have a comment, please us. Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.
News Article | November 8, 2016
Patients who undergo minimally invasive heart valve replacement, known as TAVR, sometimes develop heart rhythm problems that necessitate placement of a permanent pacemaker. However, when a pacemaker is needed soon after TAVR, patients often have worse outcomes than those who did not need a pacemaker, according to a study published in JACC: Cardiovascular Interventions. The study shows that the risks are both short- and long-term and include lengthier hospital and intensive care unit stays as well as a greater risk of death. "While pacemakers can and do help save lives, what our study shows is that when they are placed within a month post-TAVR, they may be associated with worsened outcomes as compared to those who did not need pacemakers," said the study's lead researcher, Opeyemi Fadahunsi, M.B.B.S., M.P.H., a cardiology fellow at Dalhousie University in Halifax, Nova Scotia. At the time the study was conducted, Fadahunsi served at Reading Health System in West Reading, Pennsylvania. Transcatheter aortic valve replacement, or TAVR, is a relatively new, minimally invasive surgical procedure that repairs the aortic heart valve without needing to remove the old valve. Often a patient spends less time recovering and avoids some of the risks associated with open-heart valve replacement. It is typically recommended for patients who are not able to undergo a traditional open-heart procedure -- many times, these are people in their 80s or 90s who have other medical conditions that make an open-heart surgery a less preferred option. Using data from the STS/ACC TVT Registry, researchers analyzed patients undergoing TAVR in the United States at 229 sites between November 2011 and September 2014 to see how permanent pacemaker implantation after having TAVR affected them. Of the 9,785 study participants, 651 needed a permanent pacemaker within 30 days of the TAVR procedure. Those who needed a permanent pacemaker had a slightly longer hospital stay as well as longer reported hours in the intensive care unit. They also had an increased risk of death from any cause at one year. In addition, they found that the combination of death from any cause or heart failure hospitalizations was increased at one year. "While TAVR is a great advance in medical care, cardiologists need to better understand both how to prevent patients from developing heart rhythm problems and why patients who need pacemakers in the setting of recent TAVR have worsened outcomes," Fadahunsi said. "We found in our study that the need for a pacemaker was more common in certain valve types and larger-sized valves, in those undergoing the procedure at an older age, and those who were sicker." In an accompanying editorial, Marina Urena, M.D., Ph.D., and Josep Rodés-Cabau, M.D., said the findings provide new insight into the conundrum of conduction abnormalities in TAVR. If confirmed, these results urge engineers, device manufacturers and physicians to work even harder to find ways to reduce the rate of permanent pacemaker placement after TAVR.
News Article | February 2, 2016
Alexandra Clark is a sustainable-food campaigner at Humane Society International. She recently presented HSI's meat reduction work at the COP21 in Paris. Prior to joining HSI, Clark worked for the vice president of the European Parliament and was responsible for a number of high-profile parliamentary initiatives on sustainable food systems. She contributed this article to Live Science's Expert Voices: Op-Ed & Insights. Global leaders in Paris accomplished much with the climate change agreement they reached late last year, but it had its shortcomings — including a failure to specifically mitigate the emissions of climate-changing gases from animal agriculture. However, outside of the Paris talks, policymakers in the European Union (EU) are beginning to advance that discussion, pushing for a shift away from diets heavy in meat, egg and dairy products, in an effort to clear the air. There is extensive research showing the outsize impacts of animal agriculture on the environment. The Food and Agriculture Organization of the United Nations (FAO) has concluded that "the livestock sector emerges as one of the top two or three most significant contributors to the most serious environmental problems, at every scale from local to global." It's not hard to see why. The process of converting energy and protein in animal feed into meat calories and protein for humans is highly inefficient: For example, a 2014 study led by Henk Westhoek for the PBL Netherlands Environmental Assessment Agency, and appearing in Global Environmental Change, found a 50 percent reduction in all EU consumption of meat, dairy and eggs would cut agricultural greenhouse gas emissions by 19 to 42 percent. Similar research that year in the journal Climatic Change found that, in the U.K., vegetarian and vegan diets had 32 percent and 49 percent lower greenhouse gas emissions , respectively, than medium-meat diets. Compared to high-meat diets, the difference was even starker, with vegan diets emitting 60 percent less greenhouse gasses. Yet, reductions aren't the projected future we face. One 2010 study by Nathan Pelletier and Peter Tyedmers at Dalhousie University, published in the Proceedings of the National Academy of Sciences, projected a 39 percent rise in emissions from animal agriculture by 2050 over year-2000 levels, accounting for more than two-thirds of the amount of greenhouse gases considered safe by 2050. Given the threats that climate change and other environmental impacts from farm animal production pose to long-term food security, there is a need for a global shift away from meat-heavy diets. Less meat for the wealthy, food security for the poor Eggs, meat and milk can continue to serve as sources of nutrition — particularly in rural areas of developing countries, which sometimes exhibit higher rates of undernutrition. Farm animals can provide a variety of supports to pastoralists, mixed farmers and landless peoples in rural areas. In rural communities around the world, people use farm animals as a means of acquiring cash income, a way to save and accumulate assets, as a food source, and as insurance against health or other financial crises. Integrated into a broader rural landscape of small farms, animals provide inputs and services for crop production. However, most farm animal production (and growth in production) is taking place in polluting and inhumane industrial farm animal production systems. These industrial systems are feeding middle- and higher-income consumers who could benefit from more plant-based diets. According to the World Health Organization (WHO), approximately 40 percent of adults across the globe are overweight, and noncommunicable diseases linked to the overconsumption of fats and energy-dense foods (such as meat, eggs and milk) are now a leading cause of illness and death worldwide. The WHO has called for an increase in the consumption of plant-based foods — specifically fruits, vegetables, legumes, whole grains and nuts — as part of the solution. Developed countries like the United States still have the highest per-capita meat consumption. However, according to the FAO, developing and emerging economies already account for the majority of meat production overall, and are projected to account for the majority of growth in animal consumption in the coming years. Developing countries where farm animal production is expanding may no longer require an overall increase in the consumption of animal source foods among all segments of their populations, as a significant proportion of their populations are already meeting or exceeding their energy requirements. Ironically, many developing countries with high levels of hunger and malnutrition now simultaneously bear the burden of an obesity-related public health crisis, with the number of overweight women already exceeding the number of underweight women in most developing countriesby 2005, according to research published in the American Journal of Clinical Nutrition. To allow for a more equitable distribution of agricultural resources and to ensure long-term food security and health for all communities around the world, society should place greater emphasis on small-scale, multipurpose, more animal-welfare-friendly and environmentally sustainable farm animal production led by small farmers. Middle- and higher-income populations should also reduce their consumption of animal products. A side event held within the U.N. climate conference — entitled "Meat: The Big Omission from the Talks on Emissions," hosted by leading international organizations such as the Royal Institute of International Affairs (Chatham House) and Humane Society International — brought together policymakers, scientists and civil society groups, and emphasized the need to reduce the number of animals raised for food. The event highlighted successful efforts around the world to achieve this goal by encouraging people to consume more plants and less meat. Jo Leinen, a German member of the European Parliament, spoke at the event, emphasizing nations' inability to mitigate climate change without shifting away from meat-centric diets. His comments came on the heels of a recently published report by Chatham House, "Changing Climate, Changing Diets: Pathways to Lower Meat Consumption," which specifically addresses potential government interventions to encourage meat and dairy reduction, ranging from public-awareness-raising campaigns to a carbon tax. Even Arnold Schwarzenegger agreed with the event premise — the former California governor, actor and bodybuilder made waves during the climate conference by calling on people to keep meat off their plates one or two days a week to address climate change, according to the BBC. And, a growing number of food service providers, educational institutions, environmental groups and other stakeholders are embracing meat-reduction initiatives such as Meatless Monday. In October, HSI launched Green Monday South Africa and a Meatless Monday campaign in Mexico with events attended by media, celebrities and other stakeholders. There are also thriving humane eating campaigns in India, China and other emerging economies where meat consumption is rapidly rising, along with problems relating obesity and chronic disease. The growing middle- and upper-class consumers in these countries are becoming increasingly sensitive to animal welfare, health and environmental issues, as exhibited by the increasing number of food companies in these regions adopting animal welfare policies, and the growth in the market for organic and other sustainable products. HSI advocates what it calls compassionate eating, or the three R's: "reducing" or "replacing" consumption of animal products, and "refining" diets by choosing products from sources that adhere to higher animal welfare standards. In the EU, those goals are gaining popularity, and there is growing public support for meeting the target of a 30 percent reduction in animal product consumption by 2030 through a variety of policy mechanisms. HSI launched this formal call in September 2015 at The Free Lunch, one of the largest food events ever held outside the European Parliament, where approximately 1,000 people, including politicians, attended in support of reducing the consumption of animal-based foods in the EU. The event featured cross-party members of the European Parliament, including the Parliament's vice president, civil society representatives and a representative of the EU Health and Food Safety Commission. Pathways to the 30 percent goal include incorporating sustainable food consumption into the EU and its member states' climate action plan; revising the European Commission's Green Public Procurement guidelines; and developing guidelines for healthy and sustainable diets. In early 2015, more than 60 cross-party members of the European Parliament wrote to European Commission President Jean-Claude Juncker and others to demand the publication of the blocked Communication on Building a Sustainable System, as well as EU sustainable dietary guidelines including a reduction in consumption of animal-based foods. The communication has been held up by a "principle of political discontinuity," practically ensuring that this important document never sees the light of day. Yet science demands more work to move this issue forward. With its overall goal and its recognition of the importance of people's consumption choices, the Paris Agreement provides a signal at the global level. The preamble of the document states that "sustainable lifestyles and sustainable patterns of consumption and production, with developed country Parties taking the lead, play an important role in addressing climate change." The parties should elaborate this at the national and subnational level. Research increasingly shows the benefits of moving toward more plant-based diets — to improve the welfare of farm animals, promote environmental sustainability and protect human health. It is time to really get to the meat of the matter and stop avoiding the elephant — or chicken or pig — in the room. Follow all of the Expert Voices issues and debates — and become part of the discussion — on Facebook, Twitter and Google+. The views expressed are those of the author and do not necessarily reflect the views of the publisher. This version of the article was originally published on Live Science. Why Does Less Meat Mean Less Heat? (Op-Ed) Copyright 2016 LiveScience, a Purch company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.
News Article | December 2, 2015
A team of researchers from the University of Maryland (UMD) and the US Army Research Laboratory (ARL) have devised a groundbreaking ‘water-in-salt’ aqueous lithium-ion (Li-ion) battery technology. This novel technology could provide the power, efficiency and longevity of today's Li-ion batteries, but without the fire risk, poisonous chemicals and environmental hazards. The team of researchers are led by Chunsheng Wang, an associate professor in UMD's Department of Chemical & Biomolecular Engineering, and Kang Xu, senior research chemist at the Sensor and Electron Devices Directorate of ARL. In a paper in Science, the researchers say their work represents a major advance in the long history of water-based (aqueous) batteries, by doubling the voltage, or power, of an aqueous battery. According to the researchers, this technology holds great promise in applications that involve large energies at kilowatt or megawatt levels, such as electric vehicles or grid-storage devices for energy harvest systems. It also holds promise for applications where battery safety and toxicity are primary concerns, such as safe, non-flammable batteries for airplanes, naval vessels or spaceships, and in medical devices like pacemakers. "Through this work we were able to increase the electrochemical window of aqueous electrolyte from less than 1.5 Volts to ~ 3.0 Volts and demonstrated high voltage aqueous full lithium-ion cell with 2.3 Volts, showing for the first time that aqueous batteries could seriously compete in terms of power and energy density with the non-aqueous lithium-ion batteries that power our mobile, digital lifestyle" said Wang, who also is affiliated with the UMD Energy Research Center and the Maryland NanoCenter. According to Lt Col (Retired) Edward Shaffer, who heads the ARL’s Energy and Power Division, this new approach has significant potential advantages over current batteries. "[It] could lead to thermally, chemically and environmentally safer batteries carried and worn by soldiers; safe, reduced-footprint energy storage for confined spaces, particularly submarines; and novel hybrid power solutions for military platforms and systems," he said. The key to this breakthrough is a type of water-based electrolyte containing ultrahigh concentrations of a carefully selected lithium salt. This approach transformed the battery's chemistry, resulting in the formation of a thin protective film on the anode electrode for the very first time in a water-based battery. Known in battery science as a solid electrolyte interphase (SEI), this protective and stabilizing film is essential to the high performance characteristics of state-of-the-art Li-ion batteries, but has only previously been achieved in non-aqueous electrolytes. "What's most important about our work is the breakthrough made at the fundamental level," said UMD postdoctoral research associate Liumin Suo, who is a member of Wang's research group and first author of the Science paper. "Prior to this work no one thought it possible to form SEI in water-based [batteries], but we demonstrated that it can happen." The UMD and ARL team compared the performance of their new ‘water-in-salt’ battery to that of other aqueous battery systems. They showed that in the other aqueous batteries high stability could only be achieved at the expense of voltage and energy density, and vice versa. However, the formation of an anode/electrolyte interphase in their ‘water-in-salt’ electrolyte allowed them to break this inverse relationship between high stability and high voltage, allowing them to achieve both simultaneously. "Researchers in the Li-ion battery field have recently found that previously ‘useless’ solvents could be made functional in Li-ion cells through the addition of high concentrations of salts, " commented Jeff Dahn, a leading battery researcher at Dalhousie University in Canada, who was not involved in the study. "The work by Suo et al. extends this idea to the case of the solvent water. By extending the operational voltage window to approximately 3 Volts, it is possible that a new generation of safer and possibly less expensive Li-ion cells could result." "Only further R&D efforts will be able to verify the practicality of this discovery, so prudence is needed in assessing the potential of this, or any basic research advance," he added. "Our finding opens an entirely new avenue to aqueous electrochemical devices, not only batteries, but also devices like supercapacitors and electroplating devices," said Xu. This story is adapted from material from the University of Maryland, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.
News Article | November 10, 2016
A new slate of individuals, not-for-profit organisations and businesses are recipients of the 2016 Nature Inspiration Awards from the Canadian Museum of Nature. They include a teen environmental ambassador, a marine research network, a multimedia company that tells nature stories, a mining company that implements environmental practices, a visionary CEO of a conservancy organisation, a company that leads workshops on sustainability, and an advocate for humane trapping standards. Winners were announced this evening at a gala hosted by the museum, which is Canada's national museum of natural history and natural sciences. These awards, inaugurated by the museum in 2014, recognize individuals, groups and organizations whose leadership, innovation and creativity connect Canadians with nature and the natural world. The 2016 awards cover seven categories: Youth (aged 17 and younger), Adults, Not-for-Profits (small to medium), Not-for-Profits (large), Businesses (small to medium), Businesses (large), and a Lifetime Achievement Award. The 2016 winners include: Ta'Kaiya Blaney, a First Nations singer and environmental youth leader; John Lounds, head of the Nature Conservancy private land trust; the Ocean Tracking Network, a research group at Dalhousie University that promotes ocean conservation; SK Films, a nature documentary leader in the IMAX film industry; the Natural Step Canada, which leads workshops focussed on creating a sustainable society; and Teck Resources, which has implemented environmental measures for its mining operations. The lifetime achievement award recognizes Neal Jotham for his concerted efforts over five decades to establish humane regulations for the fur-trapping industry. Videos about each of the winners can be seen at nature.ca. "There are many reasons that drive people and organisations to seek a more healthy engagement with the natural world. This year's winners reflect the scope of this involvement and they are an inspiration for others," says Meg Beckel, CEO and President of the Canadian Museum of Nature, which developed the awards. "We congratulate not only the winners, but also all those who submitted nominations this year, and we are grateful for the opportunity to recognize their achievements." A jury selected the winners after paring down the applications to a shortlist. Winners receive $5,000 that they can designate to a program of their choice. The 2016 awards were supported by presenting sponsor Enbridge, Inc. and media sponsors The Walrus and The Globe and Mail. Bruce Power was a category sponsor (Not-for-Profits, large). "We are pleased to support the 2016 Nature Inspiration Awards, which recognizes the diverse activities and projects that Canadians are undertaking to promote environmental innovation and sustainability," says Linda Coady, Chief Sustainability Officer, Enbridge Inc. "This year's group of winning individuals and organizations are truly inspiring, and it is our privilege to help sponsor these national awards." As President and CEO, John Lounds has guided the Nature Conservancy of Canada to become Canada's leading private land trust. Working with individuals and groups, this not-for-profit works to conserve more than one million hectares of ecologically significant land. Lounds has tripled the Nature Conservancy's budget and continues to inspire staff and volunteers through his leadership. At age 10, Ta'Kaiya's first song and video "Shallow Waters" brought international attention to the impact of oil spills on otter populations in British Columbia. She works with the Salish Sea Youth Foundation, a Canadian First Nations Youth organisation dedicated to the restoration of wildlife populations in the Salish Sea. As a UN Youth Ambassador for Native Children's Survival, she also champions the rights of indigenous youth in environmental protection. The Natural Step Canada coordinates workshops to make meaningful progress toward a sustainable society. Using a set of principles to define environment sustainability, Natural Step has successfully worked with dozens of companies to realign company operations. Its Change Labs, and IMPACT! Champions programs bring together businesses, governments, NGOs and individuals for discussion and resolution of environmental conflicts. The Ocean Tracking Network, based at Dalhousie University, brings together researchers and marine experts from around the world to monitor aquatic life. The network tracks the movements, migrations and habitat use of marine animals. The collected data in turn serves communities and governments to manage regional and global concerns, from fisheries management to impacts of climate change. For more than 18 years, SK Films has been creating and distributing multimedia productions about nature. The company is a leader in the Giant Screen/IMAX® industry, and inspires viewers to take action about the environment. Recent productions include Flight of the Butterflies 3D and the Water Brothers, a TV and online series that includes hands-on information and ideas for projects. Teck Resources has developed an environmental-management strategy to mitigate, or avoid the environmental impacts of its mining operations. Careful planning and judicious investments are focussed on helping closed mines return to a state of net-positive biodiversity, with self-sustaining ecosystems that can be used for years to come. Over five decades, Neal Jotham has played a central role in the creation and adoption of international standards on humane animal traps used in the fur industry. First as a volunteer, and then as executive director of the Canadian Federation of Humane Societies, he always remained true to his goal: to improve the animal-welfare aspects of trapping. Through Neal's efforts, an international humane trap standard was adopted in 1999, and recognized through a trade agreement between Canada, the European Union and the Russian Federation. In addition to Meg Beckel, the jury included Shelley Ambrose, Executive Director/Co-Publisher, The Walrus; Linda Coady, Chief Sustainability Officer, Enbridge Inc.; Jack Cockwell, Chairman/CEO, Partners Limited; Philip Crawley, Publisher, The Globe and Mail; John Geiger, CEO, Royal Canadian Geographic Society; Geoff Green, Founder and Executive Director, Students on Ice; and Arnold Witzig, Co-Founder, Arctic Inspiration Prize. About the Canadian Museum of Nature: The Canadian Museum of Nature is Canada's national museum of natural history and natural sciences. The museum provides evidence-based insights, inspiring experiences and meaningful engagement with nature's past, present and future. It achieves this through scientific research, a 14.6-million specimen collection, education programs, signature and travelling exhibitions, and a dynamic web site, nature.ca.
News Article | March 9, 2016
The Canadian government is all about thwarting Islamic “radicalization,” except when it’s not. In response to the specter of domestic terrorism, continually raised by politicians and further buoyed by tragic explosions of real violence like the shooting at Parliament Hill in 2014, Canada has given its security forces broad new powers under Bill C-51. These shadowy powers include the ability for agents to secretly intervene in the personal lives of citizens suspected of turning to radical Islam, which the Canadian Security Intelligence Service has reportedly exercised more than a dozen times. It’s curious, then, that Canada’s chief of defence staff Jonathan Vance told media this week that Canada needs to purchase armed drones for the first time (instead of drones solely outfitted for surveillance) in order to fight enemies “like ISIL,” otherwise known as ISIS or IS. After all, the US drone program has often been singled out as one of the prime drivers of radicalization—instead of crushing opposition, drone programs as we’ve known them have added fuel to the fire. A Canadian drone program would be no different. Indeed, a Canadian drone mission against an enemy “like ISIL"—likely meaning in the Middle East—could mean engaging in missions similar to the recently-ended bombing campaigns in Iraq and Syria, the cessation of which was a cornerstone of the Liberal platform. “What I have seen with ISIS propaganda is that they often point to the drone program as a way to highlight sloppy civilian casualties or as a way to say: look at these guys, they don’t fight like us, they’re cowards, things like that,” said Amarnath Amarasingam, a post-doctoral fellow at Dalhousie University and expert in domestic radicalization. Whether this will lead to radicalization at home or not is tough to say, Amarasingam emphasized, because the issue is not drones or no drones—it’s about involvement in the conflict, pure and simple. “There does seem to be an inconsistency there with the original plan, which was to pull out the bombing campaign, and now arguing that there should be drones involved,” Amarasingam said. Parliament Hill shooter Michael Zehaf-Bibeau explained in a videotaped manifesto that his act of violence was spurred by Canada “fighting and bombing us and creating a lot of terror in our countries and killing us and killing our innocents.” Zehaf-Bibeau’s comments were a chilling reminder that military intervention abroad often engenders, unfortunately, utterly predictable reactions with tragic results. As early as 2011, the CIA’s former drone chief said on Frontline, “We have helped to bring about the situation that we most fear.” Since then, the idea that drone strikes—really, the disparity between their supposed precision and the reports of civilian deaths—feed back into the radical propaganda machine has been repeated by policy experts. In Yemen, Pakistan, and elsewhere, popular anger against the US and its airborne war machines has risen up. With such a demonstrable history of blowback to foreign drone programs, you’d probably think that the Canadian army has a pretty damn good reason for beating its chest in the name of military procurement. This is not exactly the case—the idea seems to be more, well, we might as well arm our drones. Vance described the need for armed drones as a need for the military to have “a range of options,” and a Department of National Defence spokesperson described the military’s approach to me in an email as being similar to buying a car in the winter. “That doesn't mean you should get a car without AC,” they wrote, “because you might want to run the AC in July.” It appears as though Canada’s military is playing the “me, too” game with its larger, more aggressive international partners, such as the US. “Basically it’s technology that has gone from being viewed as sci-fi to the new normal of war,” war futurist and New America Foundation strategist Peter Singer wrote me in an email. “Now, having the weapon is a different question from how you use it.” The debate over whether Canada should purchase drones purely for surveillance or long-distance assassination will continue, and we would do well to remember that drones don’t win hearts and minds—they obliterate them.
News Article | November 7, 2016
Patients who undergo minimally invasive heart valve replacement, known as TAVR, sometimes develop heart rhythm problems that necessitate placement of a permanent pacemaker. However, when a pacemaker is needed soon after TAVR, patients often have worse outcomes than those who did not need a pacemaker, according to a study published today in JACC: Cardiovascular Interventions. The study shows that the risks are both short- and long-term and include lengthier hospital and intensive care unit stays as well as a greater risk of death. "While pacemakers can and do help save lives, what our study shows is that when they are placed within a month post-TAVR, they may be associated with worsened outcomes as compared to those who did not need pacemakers," said the study's lead researcher, Opeyemi Fadahunsi, M.B.B.S., M.P.H., a cardiology fellow at Dalhousie University in Halifax, Nova Scotia. At the time the study was conducted, Fadahunsi served at Reading Health System in West Reading, Pennsylvania. Transcatheter aortic valve replacement, or TAVR, is a relatively new, minimally invasive surgical procedure that repairs the aortic heart valve without needing to remove the old valve. Often a patient spends less time recovering and avoids some of the risks associated with open-heart valve replacement. It is typically recommended for patients who are not able to undergo a traditional open-heart procedure--many times, these are people in their 80s or 90s who have other medical conditions that make an open-heart surgery a less preferred option. Using data from the STS/ACC TVT Registry, researchers analyzed patients undergoing TAVR in the United States at 229 sites between November 2011 and September 2014 to see how permanent pacemaker implantation after having TAVR affected them. Of the 9,785 study participants, 651 needed a permanent pacemaker within 30 days of the TAVR procedure. Those who needed a permanent pacemaker had a slightly longer hospital stay as well as longer reported hours in the intensive care unit. They also had an increased risk of death from any cause at one year. In addition, they found that the combination of death from any cause or heart failure hospitalizations was increased at one year. "While TAVR is a great advance in medical care, cardiologists need to better understand both how to prevent patients from developing heart rhythm problems and why patients who need pacemakers in the setting of recent TAVR have worsened outcomes," Fadahunsi said. "We found in our study that the need for a pacemaker was more common in certain valve types and larger-sized valves, in those undergoing the procedure at an older age, and those who were sicker." In an accompanying editorial, Marina Urena, M.D., Ph.D., and Josep Rodés-Cabau, M.D., said the findings provide new insight into the conundrum of conduction abnormalities in TAVR. If confirmed, these results urge engineers, device manufacturers and physicians to work even harder to find ways to reduce the rate of permanent pacemaker placement after TAVR. The American College of Cardiology is a 52,000-member medical society that is the professional home for the entire cardiovascular care team. The mission of the College is to transform cardiovascular care and to improve heart health. The ACC leads in the formation of health policy, standards and guidelines. The College operates national registries to measure and improve care, offers cardiovascular accreditation to hospitals and institutions, provides professional medical education, disseminates cardiovascular research and bestows credentials upon cardiovascular specialists who meet stringent qualifications. For more, visit acc.org. The Journal of the American College of Cardiology is the most widely read cardiovascular journal in the world and is the top ranked cardiovascular journal for its scientific impact. JACC is the flagship for a family of journals that publish peer-reviewed research on all aspects of cardiovascular disease. JACC: Cardiovascular Interventions, JACC: Cardiovascular Imaging and JACC: Heart Failure also rank among the top ten cardiovascular journals for impact. JACC: Clinical Electrophysiology and JACC: Basic Translational Science are the newest journals in the JACC family. Learn more at JACC.org.
Dufton M.,Dalhousie University |
Franz-Odendaal T.A.,Mount Saint Vincent University
Developmental Dynamics | Year: 2015
Background: Understanding differences in tissue morphology has not been well researched, yet provides crucial insight into evolution. We investigate the effect of eye reduction on the shape of surrounding bones by examining two morphs of the Mexican tetra (Tinaja cavefish and sighted fish), F1 intermediates, zebrafish, a sighted tetra after lens removal and a zebrafish mutant, bum-/-, which has a degenerating lens. Results: Significantly, by comparing the skulls, we show that there are broadly similar effects on bone shape after eye reduction with bones posterior and dorsal to the eye consistently most affected in both species. We conclude that there are conserved mechanisms underlying bone shape changes in response to a reduced or lost eye. Of interest, when we compare the shapes of individual bones and the mode of eye reduction, differences suggest that the finer details of these underlying mechanisms may indeed vary. We also show that cavefish occupy a unique morphospace with respect to skull morphology and that F1 intermediates are most similar to sighted fish than their cavefish parent. Conclusions: This study highlights the dynamic nature of the vertebrate skull and its ability to respond to tissue changes within the head, a topic which has been largely overlooked in the literature. © 2015 Wiley Periodicals, Inc.
Kuparinen A.,University of Helsinki |
Hardie D.C.,Canadian Department of Fisheries and Oceans |
Hutchings J.A.,Dalhousie University
Evolutionary Applications | Year: 2012
Arguably the most fundamental of trade-offs in life-history evolution is the increase in natural mortality resulting from sexual maturity and reproduction. Despite its central importance, this increase in mortality, a survival cost, garners surprisingly little attention in fish and fisheries modeling studies. We undertook an exploratory analysis to evaluate the consequences of this omission for life-history projections. To this end, we developed a simulation approach that integrates quantitative genetics into the ecological dynamics of a fish population and parameterized the model for Atlantic cod (Gadus morhua, L.). When compared to simulations in which the mortality of immature and mature individuals is equal, the inclusion of a survival cost results in larger asymptotic body size, older age at maturity, and larger size at maturity. We also find that measures of population productivity (spawning stock biomass, recruits-per-spawner) are overestimated if the survival cost is excluded. This sensitivity of key metrics of population growth rate and reproductive capacity to the magnitude of the survival cost of reproduction underscores the need to explicitly account for this trade-off in projections of fish population responses to natural and anthropogenic environmental change, including fisheries. © 2011 Blackwell Publishing Ltd.
Mahmoudi M.,Pasteur Institute of Iran |
Mahmoudi M.,Tehran University of Medical Sciences |
Hosseinkhani H.,National Yang Ming University |
Hosseinkhani M.,Mount Sinai School of Medicine |
And 6 more authors.
Chemical Reviews | Year: 2011
Fetal stem cells, which can be isolated from the organs of fetuses, differentiate along multiple lineages. Their advantages over their adult counterparts include better intrinsic homing and engraftment and lower immunogenicity, and they are less ethically contentious. It is noteworthy that Mesenchymal Stem Cells (MSC) can be activated and mobilized at the site of damaged tissue. Since vascular delivery suffers from a pulmonary first pass effect, direct or systemic injection of MSCs into the damaged tissue is preferred, particularly in the case of versatile tissue ischemia. Ultrasound applies acoustic energy with a frequency above human hearing (20 kHz). Ultrasound imaging or sonography scanners operate between 2 and 13 MHz. The frequency determines the image's spatial resolution and the penetration depth into the examined patient.
Mahmoudi M.,Pasteur Institute of Iran |
Mahmoudi M.,Tehran University of Medical Sciences |
Azadmanesh K.,Pasteur Institute of Iran |
Shokrgozar M.A.,Pasteur Institute of Iran |
And 3 more authors.
Chemical Reviews | Year: 2011
A scientific review presents a broad overview of the effect of nanoparticles on the cell life cycle and their corresponding phase arresting the existing data. A comprehensive description of the available assays for probing the effect of nanoparticles on the cell life cycle is also presented. The cell cycle corresponds to a series of events which lead the cell to its division and duplication. The cell cycle can be divided into two brief periods in eukaryotes, such as the interphase during which the cell grows and accumulates nutrients needed for mitosis and DNA replication and the mitosis phase in which the cell splits itself into two distinct daughter cells. The mitosis phase corresponds to the actual cell division and requires significant amounts of energy. The final division is called cytokinesis after which the two daughter cells produced restart the cell cycle.
Mayerhofer M.S.,Saint Mary's University, Halifax |
Kernaghan G.,Mount Saint Vincent University |
Harper K.A.,Dalhousie University
Mycorrhiza | Year: 2013
Fungal root endophytes are plant associates that colonize root tissue internally without causing any obvious harm to their host. Although ubiquitous, this relationship is not well understood. Our objectives were to determine the effects of fungal root endophyte inoculation on plant biomass and nitrogen concentration by conducting an extensive meta-analysis. We also explored the effects of experimental conditions on the host-endophyte relationship. We performed analyses weighted with non-parametric variance on plant response to root endophytes from the Ascomycetes (excluding the Clavacipitaceae), including categorical analyses of 21 experimental factors, ranging from the identity of the host and the endophyte, to the composition of the growing medium. The response of total biomass to endophyte inoculation was 18 % lower than non-inoculated controls, while individually, root biomass, shoot biomass, and nitrogen concentration responses to endophyte inoculation were neutral. The identities of both the host and the endophyte had an influence, as did the original source of the endophyte (whether or not the isolate used originated from the same host species). Experimental conditions also influenced the plant-endophyte relationship, with the most important being the availability and sources of carbon and organic nitrogen, particularly peat moss. Although our analysis demonstrates that overall plant biomass and nitrogen concentration responses to ascomycetous root endophyte inoculation is neutral to negative, these results are somewhat confounded by among-study differences in experimental conditions, which undoubtedly contribute to the high levels of variability in plant response seen in the literature. © 2012 Springer-Verlag.
Johnstone D.L.,Dalhousie University |
O'Connell M.F.,Canadian Department of Fisheries and Oceans |
Palstra F.P.,CNRS Eco-anthropology and Ethnobiology |
Ruzzante D.E.,Dalhousie University
Molecular Ecology | Year: 2013
We describe temporal changes in the genetic composition of a small anadromous Atlantic salmon (Salmo salar) population from South Newfoundland, an area where salmon populations are considered threatened (COSEWIC 2010). We examined the genetic variability (13 microsatellite loci) in 869 out-migrating smolt and post-spawning kelt samples, collected from 1985 to 2011 for a total of 22 annual collections and a 30 year span of assigned cohorts. We estimated the annual effective number of breeders (Nb) and the generational effective population size (Ne) through genetic methods and demographically using the adult sex ratio. Comparisons between genetic and demographic estimates show that the adult spawners inadequately explain the observed Ne estimates, suggesting that mature male parr are significantly increasing Nb and Ne over the study period. Spawning as parr appears to be a viable and important strategy in the near absence of adult males. © 2013 Blackwell Publishing Ltd.
Stairs C.W.,Dalhousie University |
Roger A.J.,Dalhousie University |
Hampl V.,Charles University
Molecular Biology and Evolution | Year: 2011
Most of the major groups of eukaryotes have microbial representatives that thrive in low oxygen conditions. Those that have been studied in detail generate ATP via pathways involving anaerobically functioning enzymes of pyruvate catabolism that are typically absent in aerobic eukaryotes and whose origins remain controversial. These enzymes include pyruvate:ferredoxin oxidoreductase, pyruvate:NADP + oxidoreductase, and pyruvate formate lyase (Pfl). Pfl catalyzes the nonoxidative generation of formate and acetyl-Coenzyme A (CoA) from pyruvate and CoA and is activated by Pfl activating enzyme (Pfla). Within eukaryotes, this extremely oxygen-sensitive pathway was first described in the hydrogenosomes of anaerobic chytrid fungi and has more recently been characterized in the mitochondria and chloroplasts of the chlorophyte alga Chlamydomonas reinhardtii. To clarify the origins of this pathway, we have comprehensively searched for homologs of Pfl and Pfla in publicly available large-scale eukaryotic genomic and cDNA sequencing data, including our own from the anaerobic amoebozoan Mastigamoeba balamuthi. Surprisingly, we find that these enzymes are widely distributed and are present in diverse facultative or obligate anaerobic eukaryotic representatives of the archaeplastidan, metazoan, amoebozoan, and haptophyte lineages. Using maximum likelihood and Bayesian phylogenetic methods, we show that the eukaryotic Pfl and Pfla sequences each form monophyletic groups that are most closely related to homologs in firmicute gram-positive bacteria. Topology tests exclude both α-proteobacterial and cyanobacterial affinities for these genes suggesting that neither originated from the endosymbiotic ancestors of mitochondria or chloroplasts. Furthermore, the topologies of the eukaryote portion of the Pfl and Pfla trees significantly differ from well-accepted eukaryote relationships. Collectively, these results indicate that the Pfl pathway was first acquired by lateral gene transfer into a eukaryotic lineage most probably from a firmicute bacterial lineage and that it has since been spread across diverse eukaryotic groups by more recent eukaryote-to-eukaryote transfer events. © 2011 The Author.
Noyce R.S.,Dalhousie University |
Noyce R.S.,Izaak Walton Killam Health Center |
Richardson C.D.,Dalhousie University |
Richardson C.D.,Izaak Walton Killam Health Center
Trends in Microbiology | Year: 2012
Measles virus (MV) causes acute respiratory disease, infects lymphocytes and multiple organs, and produces immune suppression leading to secondary infections. In rare instances it can also cause persistent infections in the brain and central nervous system. Vaccine and laboratory-adapted strains of MV use CD46 as a receptor, whereas wild-type strains of MV (wtMV) cannot. Both vaccine and wtMV strains infect lymphocytes, monocytes, and dendritic cells (DCs) using the signaling lymphocyte activation molecule (CD150/SLAM). In addition, MV can infect the airway epithelial cells of the host. Nectin 4 (PVRL4) was recently identified as the epithelial cell receptor for MV. Coupled with recent observations made in MV-infected macaques, this discovery has led to a new paradigm for how the virus accesses the respiratory tract and exits the host. Nectin 4 is also a tumor cell marker which is highly expressed on the apical surface of many adenocarcinoma cell lines, making it a potential target for MV oncolytic therapy. © 2012 Elsevier Ltd.
McNeil D.S.,Dalhousie University |
Baumhauer J.F.,University of Rochester |
Glazebrook M.A.,Dalhousie University
Foot and Ankle International | Year: 2013
Background: The aim of this article is to provide an evidence-based literature review and assessment of the quality of literature regarding operative interventions for hallux rigidus. Methods: A comprehensive evidence-based literature review of the PubMed database was conducted on June 24, 2011, identifying 586 articles, of which 135 were relevant in assessing the efficacy of common operative interventions for hallux rigidus. The 135 studies were then assigned a level of evidence (I-V) to denote quality. They were then reviewed to provide a grade of recommendation (A-C, I) in support of or against the operative intervention in treatment of hallux rigidus. Results: Based on the results of this evidence-based review, there is fair evidence (grade B) in support of arthrodesis for treatment of hallux rigidus. There is poor evidence (grade C) in support of cheilectomy, osteotomy, implant arthroplasty, resection arthroplasty, and interpositional arthroplasty for treatment of hallux rigidus. There is insufficient evidence (grade I) for cheilectomy with osteotomy for treatment of hallux rigidus. Conclusion: There are no consistent findings in comparative studies that are properly powered with validated and appropriate outcome measures to allow any definitive conclusions on which procedure is best. However, the grade B recommendation assigned to arthrodesis may make it the logical leading candidate for future high-quality randomized controlled trials. Clearly, further studies - ideally, high-quality Level I randomized controlled trials with validated outcome measures - are needed to allow stronger recommendations to be made. Level of Evidence: Level III, systematic review. © The Author(s) 2013.
Ma K.,Cornell University |
Werner-Zwanziger U.,Dalhousie University |
Zwanziger J.,Dalhousie University |
Wiesner U.,Cornell University
Chemistry of Materials | Year: 2013
Mesoporous silica nanoparticles (MSNs) have recently attracted a lot of interest for future nanotheranostic applications because of their large surface-area and high biocompatibility. However, studies to date of MSNs are confined to >10 nm particle sizes which may result in unfavorable biodistribution characteristics for in vivo experiments and hence limit their clinical applications. Here we provide a full account of a synthesis approach to ultrasmall sub-10 nm mesoporous silica nanoparticles with narrow size distributions and homogeneous porous particle morphology. Key features enabling this structure control are (i) fast hydrolysis, (ii) slow condensation, and (iii) capping of particle growth by addition of a PEG-silane at different time-points of the synthesis. Variation of synthesis conditions including monomer/catalyst concentrations, temperature, and time-point of PEG-silane addition leads to synthesis condition-particle structure correlations as mapped out by a combination of results from data analysis of dynamic light scattering (DLS) and transmission electron microscopy (TEM) measurements. Results establish precise control over average particle diameter from 6 to 15 nm with increments below 1 nm. Solid state nuclear magnetic resonance (NMR) measurements, zeta-potential measurements, and thermogravimetric analysis (TGA) were conducted to reveal details of the particle surface structure. Long-term particle stability tests in deionized (DI) water and phosphate buffered saline (PBS) 1X buffer solution were performed using DLS demonstrating that the PEGylated particles are stable in physiological environments for months. Fluorescent single pore silica nanoparticles (mC dots) encapsulating blue (DEAC) and green (TMR) dyes were synthesized and characterized by a combination of DLS, TEM, static optical spectroscopy, and fluorescence correlation spectroscopy (FCS) establishing probes for multicolor fluorescence imaging applications. The ultraprecise particle size control demonstrated here in particular for sizes around and below 10 nm may render these particles an interesting subject for further fundamental studies of porous silica particle formation mechanisms as well as for sensing, drug delivery, and theranostic applications. © 2013 American Chemical Society.
Vazquez-Rowe I.,University of Santiago de Compostela |
Vazquez-Rowe I.,CRP Henri Tudor |
Tyedmers P.,Dalhousie University
Marine Policy | Year: 2013
Technical efficiency, uncertainties in data quality and natural fluctuations in fishing stocks constitute potential sources of fishing vessel inefficiency. Moreover, debate is on-going as to whether the skill of the fishermen ("skipper effect") is an underlying actor in fishing efficiency. Therefore, this article monitors, calculates and quantifies the inefficiency caused by the "skipper effect", if any, through the use of data envelopment analysis (DEA), with the aim of determining whether best practice target operational values in DEA, and their associated environmental impact reductions through LCA+DEA methodology, are achievable beyond the theoretical baseline they involve. A window analysis model is applied to the US menhaden fishery, a purse seining fleet with high homogeneity, since it is owned by the same company, with similar vessel and management characteristics. Results revealed relevant inefficiency levels in the four ports assessed, suggesting the existence of a "skipper effect" in all of them. Strong variances between vessels were identified, not only on an annual mean basis, but also per week of study. These variances could be attributed to random variation through time, if it were not for the fact that best performing vessels managed to repeatedly perform at high efficiency rates throughout the period. Moreover, standard deviations of low efficiency vessels were higher in all ports. Consequently, best performing targets calculated in LCA+DEA may be difficult to achieve in fleets where skipper skill strongly influences the sources of inefficiency. In these cases, the results suggest that resource minimization should be linked to specific measures to improve the individual skills of low performing vessels to attain best practice targets. © 2012 Elsevier Ltd.
Matta C.F.,Mount Saint Vincent University |
Matta C.F.,Dalhousie University
Journal of Computational Chemistry | Year: 2010
This article compares molecular properties and atomic properties defined by the quantum theory of atoms in molecules (QTAIM) obtained from three underlying levels of theory: MP2(full), density functional theory (DFT) (B3LYP), and Hartree-Fock (H-F). The same basis set (6-31.1+ +G(d,p)) has been used throughout the study. The calculations and comparisons were applied to a set of 30 small, molecules representing common fragments of biological, molecules. The molecular properties investigated are the energies and the electrostatic moments (up to and including the quadrupoles), and the atomic properties include electron populations (and atomic charge), atomic dipolar and quadrupolar polarizations, atomic volumes, and corrected and raw atomic energies. The Cartesian distance between dipole vectors and the Frobenius distance between the quadrupole tensors calculated at the three levels of theory provide a measure of their correlation (or lack thereof). With the exception of energies (atomic and molecular), it is found that both DFT and H-F are in excellent agreement with MP2, especially with regards to the electrostatic mutipoles up to the quadrupoles, but DFT and MP2 agree better in almost all studied properties (with the exception of molecular geometries). QTAIM properties whether obtained from H-F, DFT(B3LYP), or MP2 calculations when, used in the construction of empirical correlations with experiment such as quantitative structure-activity(or property)-relationships (QSAR/QSPR) are equivalent (because the properties calculated at the three levels are very highly correlated among themselves with r2 typically >0.95, and therefore preserving trends). These results suggest that the massive volume of results that were published in the older literature at the H-F level, is valid especially when used to study trends or in QSAR or QSPR. studies, and, as long as our test set of molecules is representative, there is no pressing need to re-evaluate them at other levels of theory except when inadequate basis sets were used by today's standards. Extensive tabulation of molecular and atomic properties at the three theoretical levels is available in the Supporting Information, including optimized geometries, molecular energies, virial ratios, molecular electrostatic moments up to and including hexadecapoles, atomic populations, atomic volumes, atomic electrostatic moments up to and including the quadrupoles, and atomic energies. © 2009 Wiley Periodicals, Inc.
Jameson-Lee M.,University of Virginia |
Garduno R.A.,Dalhousie University |
Hoffman P.S.,University of Virginia
Molecular Microbiology | Year: 2011
In Gram-negative bacteria, thiol oxidoreductases catalyse the formation of disulphide bonds (DSB) in extracytoplasmic proteins. In this study, we sought to identify DSB-forming proteins required for assembly of macromolecular structures in Legionella pneumophila. Here we describe two DSB-forming proteins, one annotated as dsbA1 and the other annotated as a 27kDa outer membrane protein similar to Com1 of Coxiella burnetii, which we designate as dsbA2. Both proteins are predicted to be periplasmic, and while dsbA1 mutants were readily isolated and without phenotype, dsbA2 mutants were not obtained. To advance studies of DsbA2, a cis-proline residue at position 198 was replaced with threonine that enables formation of stable disulphide-bond complexes with substrate proteins. Expression of DsbA2 P198T mutant protein from an inducible promoter produced dominant-negative effects on DsbA2 function that resulted in loss of infectivity for amoeba and HeLa cells and loss of Dot/Icm T4SS-mediated contact haemolysis of erythrocytes. Analysis of captured DsbA2 P198T-substrate complexes from L. pneumophila by mass spectrometry identified periplasmic and outer membrane proteins that included components of the Dot/Icm T4SS. More broadly, our studies establish a DSB oxidoreductase function for the Com1 lineage of DsbA2-like proteins which appear to be conserved among those bacteria also expressing T4SS. © 2011 Blackwell Publishing Ltd.
News Article | December 1, 2016
Ethics of crowdfunding for medical care, an argument for fewer clinical trials, and more in the November-December 2016 issue Ethics of crowdfunding for medical care, an argument for fewer clinical trials, and more in the November-December 2016 issue. Crowdfunding for Medical Care: Ethical Issues in an Emerging Health Care Funding Practice Jeremy Snyder Crowdfunding for medical care, which has become relatively common, has received a lot of media attention, but little has been written about the ethical issues that it raises. While the money can make an important difference in the lives of crowdfunding users, the author cites several ethical concerns, including the potential for fraud and misinformation by those seeking funds, the potential for worsening health care inequities, and a risk to users' privacy. Snyder, an associate professor at Simon Fraser University, argues that medical crowdfunding "is a symptom and cause of, rather than a solution to, health system injustices and that policy-makers should work to address the injustices motivating the use of crowdfunding sites for es¬sential medical services." The quantity of published clinical research, much of it poor quality, has increased so much that physicians cannot keep up with it and patients are likely suffering. The author proposes that the number of clinical studies be reduced and that a way to do that would be for research ethics committees to permit only studies of high quality, meaning pragmatic trials that aim to provide evidence that directly supports clinical decision-making in usual care settings. Borgerson is an associate professor of philosophy at Dalhousie University in Canada. Also in this issue: "What Pacemakers Can Teach Us about the Ethics of Maintaining Artificial Organs," At Law ("International Perspectives on Physician Assistance in Dying"), and Policy & Politics ("Religious Hospitals and Patient Choice").
News Article | December 9, 2016
During pregnancy, coming down with the flu is riskier than usual. During the 2009 outbreak of H1N1 influenza, for example, pregnant women made up 5 percent of all U.S. deaths due to the virus, despite constituting only about 1 percent of the population at the time. The risk is greater as pregnancy continues, according to a 2010 paper in the journal JAMA, which found that, of the 56 deaths among pregnant women in the epidemic, 36 of those deaths (64.3 percent) happened in the third trimester. Sixteen, or just over a quarter, of the deaths happened in the second trimester and only four (7 percent) occurred in the first trimester. Fortunately, there are ways pregnant women can protect themselves from the flu, experts say. [Blossoming Body: 8 Odd Changes That Happen During Pregnancy] "The [flu] vaccine is the No. 1 priority for any pregnant woman," said Dr. Regan Theiler, the division director of general OB-GYN at Dartmouth-Hitchcock Medical Center in New Hampshire. "It's very effective, and not only does it protect mom, but the antibodies transfer across the placenta and protect the baby for the first six months of life." The reasons why the flu is particularly risky for pregnant women aren't entirely understood. Researchers know that a woman's immune system changes in complex ways during pregnancy in order to allow the body to tolerate the fetus, which, after all, is genetically half-alien. Some of these changes have to do with the placenta, which produces certain molecules to wall off the developing fetus from the mother's immune system. Other body-wide effects are more complex. For example, a 2014 review in the journal Reproductive Sciences reported that pregnant women have lower numbers of a type of immune cell called dendritic cells circulating in their blood. Dendritic cells capture fragments of invading germs and then present these fragments to other immune cells, which use the information to launch immune responses. Despite this decrease in dendritic cells, some of the fragment-capturing receptors on their surface actually increase, potentially boosting a woman's immune response. In other words, while there are fewer dendritic cells, the ones that are present can capture more germ fragments. In addition, some pro-inflammatory chemicals that promote inflammation, including molecules called cytokines, also increase. [Flu Shot Facts & Side Effects (Updated for 2016-2017)] Overall, these factors may promote an increased immune response during pregnancy — and that's not necessarily a great thing. A small 2014 study in the journal PNAS found that pregnant women's immune systems have a stronger natural killer cell and T-cell responses to the flu than nonpregnant women's immune systems do. These two types of immune cells, when supercharged, may actually create extra damage in the pregnant woman's respiratory tract, increasing her risk of developing other problems from the flu, the researchers suggested. A major reason pregnant women who get the flu are at high risk may simply be that their heart and lungs are already taxed, Theiler said. Pregnant women "are sort of using all their ability to take in oxygen and move their blood around," she told Live Science. When the flu virus attacks the cells of the respiratory system, the additional burden may be too much to bear, Theiler said. Death from flu often comes because the virus opens up the opportunity for bacteria to move in, she said, which can lead to pneumonia that, in turn, leads to sepsis, or body-wide inflammation. In contrast with the Zika virus, which causes mild illness in the mother but can have devastating effects on the developing fetus, the influenza viruses rarely cross the placenta to infect the fetus directly, Theiler said. Nevertheless, flu has long been linked to increased risks of stillbirth, miscarriage and preterm delivery. A 1961 study in the American Journal of Public Health on 611 pregnant women found that those with a flu infection were more likely to have had a miscarriage, a stillbirth or a preterm delivery than those with no infection (though the number of women uninfected was too low to draw firm statistical conclusions). More recently, a study of a 1989 outbreak of influenza among pregnant women at one medical center in London suggested a link between infection and fetal and newborn mortality. And a 2013 study in The New England Journal of Medicine found that women in Norway who got the flu during pregnancy had nearly twice the risk of losing the baby before birth as women who didn't catch the flu. Getting the flu vaccine is the best step a pregnant woman can take to protect herself and her baby, Theiler said. [6 Flu Vaccine Myths] In 2014, researchers at Dalhousie University in Nova Scotia found, after controlling for other factors, that getting the flu vaccine during pregnancy reduced the risk of preterm birth or giving birth to a low-birth-weight infant. The same New England Journal of Medicine study that found an increased risk of fetal death with flu infection during pregnancy also found that the flu vaccine was very effective, reducing the risk of flu during pregnancy by 70 percent. Evidence also suggests that the flu vaccine is very safe during pregnancy. A study published Nov. 29 in the journal JAMA Pediatrics looked at a large registry of patients with Kaiser Permanente Northern California and found no evidence that the flu vaccine (or the flu) increased the risk of autism in children. Nor have researchers found evidence of a heightened risk of adverse effects from the vaccine in pregnant women. A 2011 study in the American Journal of Obstetrics & Gynecology, for example, examined reports submitted to the Vaccines Adverse Event Reporting System, a federal system used to collect information about negative reactions to vaccines. Reports in the database do not have to be confirmed by doctors to be included. The study found no evidence of unusual patterns of adverse events during pregnancy or in infants, the researchers wrote. Direct comparisons turn up similar results. A 2013 study in the journal Obstetrics & Gynecology compared nearly 76,000 women who received the flu vaccine during pregnancy with almost 150,000 women who didn't and found no increase in adverse effects among the vaccinated women. Another study in the same journal that year used similar data and found no additional risk from vaccination for common pregnancy complications such as high blood pressure, morning sickness or pulmonary embolism. Handwashing is the most effective hygiene measure to prevent the flu, Theiler said. Still, if a pregnant women is in close contact with an infected individual — say, an older child — she should call her doctor right away, rather than just relying on handwashing, Theiler added. If the seasonal flu strain isn't well-covered by that year's vaccine, many physicians might want to preemptively treat the woman with anti-viral drugs to ensure she doesn't get sick, because the consequences of infection can be dire, Theiler said. Any pregnant woman who experiences flu symptoms should call her doctor right away, Theiler said. "They shouldn't wait it out at home or tough it out like they might do if they weren't pregnant," Theiler said. Again, anti-viral drugs would be the treatment of choice. The bottom line, Theiler said, is that the flu is a "very bad thing for maternal mortality that's easy for us to prevent." In 2009, she said, the H1N1 epidemic increased the rate of deaths among pregnant women. That rate is typically very stable, Theiler said. The rate of deaths "noticeably" increased just because of the flu, she said, "so that's a scary thing for us."
Nyaga G.N.,Northeastern University |
Whipple J.M.,Michigan State University |
Lynch D.F.,Dalhousie University
Journal of Operations Management | Year: 2010
Firms are building collaborative relationships with their supply chain partners in order to achieve efficiencies, flexibility, and sustainable competitive advantage. However, it is unclear if collaborative relationships provide benefits that compensate for the additional expense associated with such relationships. Further, it is unclear what factors promote successful collaborations. This research examines collaborative relationships in two separate studies using structural equation modeling: one study examines buyers' perceptions and the second study examines suppliers' perceptions. The two studies are then compared using invariance testing in order to determine economic and relational factors that drive satisfaction and performance from each party's perspective. Results show that collaborative activities, such as information sharing, joint relationship effort, and dedicated investments lead to trust and commitment. Trust and commitment, in turn, lead to improved satisfaction and performance. Results from the two independent studies exhibit similarities and differences; while the conceptual model is highly similar, certain paths vary in their significance and/or their importance across buyer and supplier firms such that buyers focus more on relationship outcomes while suppliers look to safeguard their transaction specific investments through information sharing and joint relationship effort. Managerial and theoretical implications of the findings are discussed. © 2009 Elsevier B.V. All rights reserved.
Colohan S.M.,Dalhousie University |
Colohan S.M.,London School of Hygiene and Tropical Medicine
Journal of Burn Care and Research | Year: 2010
Burn injuries are a significant problem with high associated morbidity and mortality. Those associated with inhalational trauma (IHT) may be associated with higher mortality, but studies on prognosis are small and underpowered. This study was designed to identify prognostic factors that increase the risk of death, to quantify this risk, and to identify existing prognostic models. An electronic search of English-language publications that identify prognostic risk factors in thermal burns including IHT was carried out. Each article was reviewed systematically, and data extraction, quality assessment, and summarization of the articles were performed. Thirteen articles that met the inclusion/exclusion criteria of this study were reviewed. Overall, the mortality rate among burn patients in this review was 13.9% (4-28.3%), with the mortality rate among those with IHT being 27.6% (7.8-28.3%). Those studies with multivariate analyses identified increasing %TBSA, presence of IHT, and increasing age as the strongest predictors for mortality in this patient population. It seems that %TBSA, presence of IHT, and age are the best predictors of mortality among the current published literature on burn prognosis. © 2010 by the American Burn Association.
Demas G.E.,Indiana University Bloomington |
Adamo S.A.,Dalhousie University |
French S.S.,Utah State University
Functional Ecology | Year: 2011
1.Communication among cells, tissues and organ systems is essential for survival. Vertebrate and invertebrate animals rely primarily on three physiological systems for intra-organismal communication: the nervous, endocrine and immune systems. Rather than acting independently of one another, these systems communicate in an integrated fashion to coordinate suites of species-appropriate physiological and behavioural responses. 2.Our understanding of how these three systems are coordinated remains incomplete, in part because the importance of the immune system as part of this regulatory network has only recently been recognized. In contrast to the well-established integrative approach to the study of the endocrine and nervous systems, the study of immunity has traditionally occurred in relative isolation from other physiological systems. Immunity was typically considered to be largely buffered from environmental perturbations. 3.In the last several decades, however, this simplistic view has changed dramatically; we now know that a wide variety of extrinsic and intrinsic factors can affect immune responses (reviewed in: Ader, Felten & Cohen 2001). This altered perspective has led to the development of new scientific disciplines including psychoneuroimmunology (Ader & Cohen 1981) and ecological immunology (Sheldon & Verhulst 1996). 4.These new research fields focus on the connections among the endocrine, nervous and immune systems. These fields also examine how environmental factors influence interactions among the three systems, and the implications of these interactions for behaviour and host defence. A comparative approach will benefit the search for the adaptive functions of these interactions. © 2010 The Authors. Functional Ecology © 2010 British Ecological Society.
Pinsky M.L.,Stanford University |
Jensen O.P.,Rutgers University |
Ricard D.,Dalhousie University |
Palumbi S.R.,Stanford University
Proceedings of the National Academy of Sciences of the United States of America | Year: 2011
Understanding which species are most vulnerable to human impacts is a prerequisite for designing effective conservation strategies. Surveys of terrestrial species have suggested that largebodied species and top predators are the most at risk, and it is commonly assumed that such patterns also apply in the ocean. However, there has been no global test of this hypothesis in the sea. We analyzed two fisheries datasets (stock assessments and landings) to determine the life-history traits of species that have suffered dramatic population collapses. Contrary to expectations, our data suggest that up to twice as many fisheries for small, low trophic-level species have collapsed compared with those for large predators. These patterns contrast with those on land, suggesting fundamental differences in the ways that industrial fisheries and land conversion affect natural communities. Even temporary collapses of small, low trophic-level fishes can have ecosystem-wide impacts by reducing food supply to larger fish, seabirds, and marine mammals.
Clackdoyle R.,Dalhousie University |
Defrise M.,University of Geneva
IEEE Signal Processing Magazine | Year: 2010
Image reconstruction from projections is the field that lays the foundations for computed tomography (CT). For several decades, the established principles were applied not only to medical scanners in radiology and nuclear medicine but also to industrial scanning. When speaking of image reconstruction from projections, one is generally considering the problem of recovering some density function from measurements taken over straight lines, or the line-integral model for short. Image reconstruction can be performed by directly applying analytic formulas derived from the theory or by using general optimization methods adapted to handling large linear systems. The latter techniques are referred to as iterative to distinguish them from the analytic (or direct) methods. This article considers only the analytic methods. The two-dimensional (2-D) reconstruction problem (or classical tomography) refers to a density function in two dimensions with measurement lines lying in the plane, and the three-dimensional (3-D) problem considers 3-D density functions and lines with arbitrary orientations in space. The widely used term 3-D imaging is potentially confusing in this context, because there are some 3-D forms of image reconstruction that are mathematically equivalent to performing 2-D reconstruction on a set of parallel contiguous planes. To emphasize the distinction between 2-D and 3-D reconstruction, the terminology fully 3-D image reconstruction (or sometimes truly 3-D reconstruction) was introduced in the late 1980s when there seemed to be very little left to do in two dimensions but a rich unexplored 3-D theory to be developed. © 2006 IEEE.
Pimchuai A.,Burapha University |
Dutta A.,University of Guelph |
Basu P.,Dalhousie University
Energy and Fuels | Year: 2010
Torrefaction improves the thermochemical properties of biomass that are relevant to combustion, co-combustion with coal, or gasification. This study examines torrefaction of rice husks and four other agriculture residues (sawdust, peanut husks, bagasse, and water hyacinth) in nitrogen. Two main operating parameters of torrefaction, temperature and residence time for the process, were varied in the range of 250-300 °C and 1-2 h, respectively. Product evolution and mass and energy losses during torrefaction were measured. Similar to other work, the torrefied products in the present work were characterized by a more brownish color, reduced moisture content and volatile matter, and increased ash, fixed carbon content, and energy density. The difference between the mass and energy yield was shown to improve for the higher torrefaction temperatures investigated. For the biomass studied, the torrefied bagasse at 300 °C and 1.5 h resulted in the highest higher heating value (HHV) of 25.68 MJ/kg of product, which was comparable to the HHV of lignite. Dependent upon the severity of the torrefaction conditions, the torrefied fuel can contain up to 98% of the original energy content on a mass basis. The combustion behavior of both raw and torrefied rice husks was studied in a spout-fluid bed combustor by measuring its temperature history at different zones. It is observed that torrefied husks ignite faster and raise the bed temperature to a higher level because of its low moisture content. © 2010 American Chemical Society.
Madureira P.A.,University of Algarve |
Waisman D.M.,Dalhousie University
International Journal of Molecular Sciences | Year: 2013
Hydrogen peroxide (H2O2) is an important second messenger in cellular signal transduction. H2O2-dependent signalling regulates many cellular processes, such as proliferation, differentiation, migration and apoptosis. Nevertheless, H2O2 is an oxidant and a major contributor to DNA damage, protein oxidation and lipid peroxidation, which can ultimately result in cell death and/or tumourigenesis. For this reason, cells have developed complex antioxidant systems to scavenge ROS. Recently, our laboratory identified the protein, annexin A2, as a novel cellular redox regulatory protein. Annexin A2 possesses a reactive cysteine residue (Cys-8) that is readily oxidized by H2O2 and subsequently reduced by the thioredoxin system, thereby enabling annexin A2 to participate in multiple redox cycles. Thus, a single molecule of annexin A2 can inactivate several molecules of H2O2. In this report, we will review the studies detailing the reactivity of annexin A2 thiols and the importance of these reactive cysteine(s) in regulating annexin A2 structure and function. We will also focus on the recent reports that establish novel functions for annexin A2, namely as a protein reductase and as a cellular redox regulatory protein. We will further discuss the importance of annexin A2 redox regulatory function in disease, with a particular focus on tumour progression. © 2013 by the authors; licensee MDPI, Basel, Switzerland.
Gibling M.R.,Dalhousie University |
Davies N.S.,Dalhousie University |
Davies N.S.,Ghent University
Nature Geoscience | Year: 2012
Fluvial landscapes diversified markedly over the 250 million years between the Cambrian and Pennsylvanian periods. The diversification occurred in tandem with the evolution of vascular plants and expanding vegetation cover. In the absence of widespread vegetation, landscapes during the Cambrian and Ordovican periods were dominated by rivers with wide sand-beds and aeolian tracts. During the late Silurian and Devonian periods, the appearance of vascular plants with root systems was associated with the development of channelled sand-bed rivers, meandering rivers and muddy floodplains. The widespread expansion of trees by the Early Pennsylvanian marks the appearance of narrow fixed channels, some representing anabranching systems, and braided rivers with vegetated islands. We conclude that the development of roots stabilized the banks of rivers and streams. The subsequent appearance of woody debris led to log jams that promoted the rapid formation of new river channels. Our contention is supported by studies of modern fluvial systems and laboratory experiments. In turn, fluvial styles influenced plant evolution as new ecological settings developed along the fluvial systems. We suggest that terrestrial plant and landscape evolution allowed colonization by an increasingly diverse array of organisms. © 2012 Macmillan Publishers Limited. All rights reserved.
Lighten J.,Dalhousie University |
Van Oosterhout C.,University of East Anglia |
Bentzen P.,Dalhousie University
Molecular Ecology | Year: 2014
The genotyping of highly polymorphic multigene families across many individuals used to be a particularly challenging task because of methodological limitations associated with traditional approaches. Next-generation sequencing (NGS) can overcome most of these limitations, and it is increasingly being applied in population genetic studies of multigene families. Here, we critically review NGS bioinformatic approaches that have been used to genotype the major histocompatibility complex (MHC) immune genes, and we discuss how the significant advances made in this field are applicable to population genetic studies of gene families. Increasingly, approaches are introduced that apply thresholds of sequencing depth and sequence similarity to separate alleles from methodological artefacts. We explain why these approaches are particularly sensitive to methodological biases by violating fundamental genotyping assumptions. An alternative strategy that utilizes ultra-deep sequencing (hundreds to thousands of sequences per amplicon) to reconstruct genotypes and applies statistical methods on the sequencing depth to separate alleles from artefacts appears to be more robust. Importantly, the 'degree of change' (DOC) method avoids using arbitrary cut-off thresholds by looking for statistical boundaries between the sequencing depth for alleles and artefacts, and hence, it is entirely repeatable across studies. Although the advances made in generating NGS data are still far ahead of our ability to perform reliable processing, analysis and interpretation, the community is developing statistically rigorous protocols that will allow us to address novel questions in evolution, ecology and genetics of multigene families. Future developments in third-generation single molecule sequencing may potentially help overcome problems that still persist in de novo multigene amplicon genotyping when using current second-generation sequencing approaches. © 2014 John Wiley & Sons Ltd.
Whitehead H.,Dalhousie University |
James R.,University of Bath
Methods in Ecology and Evolution | Year: 2015
In the analysis of animal social networks, a common challenge has been distinguishing affiliations - active preferences of pairs of individuals to interact or associate with one another - from other, structural, causes of association or interaction. Such structural factors can include patterns of use of the habitat in time and space, gregariousness and differential association rates among age/sex classes. In an approach with similarities to the multiple regression quadratic assignment procedures test, we suggest calculating generalized affiliation indices as the residuals from a regression of the measures of association or interaction on structural predictor variables, such as gregariousness and spatiotemporal overlap. If the original data are association indices or counts of interactions, then generalized linear models with binomial or Poisson error structures, respectively, can be used in place of linear regression. Anscombe or deviance residuals can be used to assess the significance of particular affiliation indices. Generalized affiliation indices can be used as the weights of links in a social network representation. They can then be portrayed in network diagrams or cluster diagrams and used to calculate network statistics, to delineate communities by maximizing modularity and to test for overall affiliation using data-stream permutation tests. We evaluate the effectiveness of such generalized affiliation indices using simulated and real association data, finding that the method removes much of the effect of structural variables on association patterns, revealing real affiliations. While the approach is very promising, it is limited by the extent to which the input predictor variables represent important structural factors. © 2015 British Ecological Society.
Lynch M.E.,Dalhousie University |
Cesar-Rittenberg P.,Dalhousie University |
Hohmann A.G.,Indiana University Bloomington
Journal of Pain and Symptom Management | Year: 2014
Context. Neuropathic pain caused by chemotherapy limits dosing and duration of potentially life-saving anti-cancer treatment and impairs quality of life. Chemotherapeutic neuropathy responds poorly to conventional treatments, and there is an urgent medical need for new treatments. Recent preclinical studies demonstrate that cannabinoid agonists suppress established chemotherapy-evoked neuropathy. Objectives. This was a pilot trial to begin to investigate a currently available cannabinoid agent, nabiximols (oral mucosal spray containing cannabinoids), in the treatment of chemotherapy-induced neuropathic pain. Methods. A randomized, placebo-controlled crossover pilot study was done in 16 patients with established chemotherapy-induced neuropathic pain. A 0-10 point numeric rating scale for pain intensity (NRS-PI) was used as the primary outcome measure. Results. When examining the whole group, there was no statistically significant difference between the treatment and the placebo groups on the NRS-PI. A responder analysis demonstrated that there were five participants who reported a two-point or greater reduction in pain that trended toward statistical significance and the number needed to treat was five. Conclusion. Chemotherapy-induced neuropathic pain is particularly resistant to currently available treatments. This pilot trial found a number needed to treat of five and an average decrease of 2.6 on an 11-point NRS-PI in five "responders" (as compared with a decrease of 0.6 with placebo) and supports that it is worthwhile to study nabiximols in a full randomized, placebo-controlled trial of chemotherapy-induced neuropathic pain. © 2014 U.S. Cancer Pain Relief Committee.
Han P.K.,Center for Outcomes Research and Evaluation |
Rayson D.,Dalhousie University
Journal of the National Cancer Institute - Monographs | Year: 2010
The end of life is a time in which both the intensity of cancer patients' needs and the complexity of care increase, heightening the need for effective care coordination between oncology and primary care physicians. However, little is known about the extent to which such coordination occurs or the ways in which it is achieved. We review existing evidence on current practice patterns, patient and physician preferences regarding involvement of oncology and primary care physicians in end-of-life care, and the potential impact of care coordination on the quality of care and health outcomes. Data are lacking on the extent to which end-of-life care is coordinated between oncology and primary care physicians. Patients appear to prefer the continued involvement of both types of physicians, and preliminary evidence suggests that coordinated care improves health outcomes. However, more work needs to be done to corroborate these findings, and many unanswered questions remain. © The Author 2010. Published by Oxford University Press. All rights reserved.
Yasuyama K.,Kawasaki Medical School |
Meinertzhagen I.A.,Dalhousie University
Journal of Comparative Neurology | Year: 2010
Recent studies in Drosophila melanogaster indicate that the neuropeptide pigment-dispersing factor (PDF) is an important output signal from a set of major clock neurons, s-LNvs (small ventral lateral neurons), which transmit the circadian phase to subsets of other clock neurons, DNs (dorsal neurons). Both s-LNvs and DNs have fiber projections to the dorsal protocerebrum of the brain, so that this area is a conspicuous locus for coupling between different subsets of clock neurons. To unravel the neural circuits underlying the fly's circadian rhythms, we examined the detailed subcellular morphology of the PDF-positive fibers of the s-LNvs in the dorsal protocerebrum, focusing on their synaptic connections, using preembedding immunoelectron microscopy. To examine the distribution of synapses, we also reconstructed the three-dimensional morphology of PDF-positive varicosities from fiber profiles in the dorsal protocerebrum. The varicosities contained large dense-core vesicles (DCVs), and also numerous small clear vesicles, forming divergent output synapses onto unlabeled neurites. The DCVs apparently dock at nonsynaptic sites, suggesting their nonsynaptic release. In addition, a 3D reconstruction revealed the presence of input synapses onto the PDF-positive fibers. These were detected less frequently than output sites. These observations suggest that the PDF-positive clock neurons receive neural inputs directly through synaptic connections in the dorsal protocerebrum, in addition to supplying dual outputs, either synaptic or via paracrine release of the DCV contents, to unidentified target neurons. © 2009 Wiley-Liss, Inc.
Hutchings J.A.,Dalhousie University |
Rangeley R.W.,WWF Canada
Canadian Journal of Zoology | Year: 2011
The collapse of Atlantic cod (Gadus morhua L., 1758) in the early 1990s, perhaps the greatest numerical loss of a Canadian vertebrate (1.5-2.5 billion reproductive individuals), is one from which the species has yet to recover. Populations, or stocks, are at or well below their conservation reference points. The lack of recovery has been linked to ongoing fishing mortality (targeted, bycatch), changes to life history (reductions in age and size at maturity, truncations in age and size structure), and increased natural mortality. Emergent and demographic Allee effects, coupled with altered interspecific interactions, render questionable the presumption that the recovery of heavily depleted populations can be reliably forecasted by population dynamical behaviour during decline. Contrary to international commitments and inconsistent with fishery rebuilding plans elsewhere, cod recovery plans exclude target and limit reference points, recovery timelines, and harvest control rules. We suggest that the long-term biodiversity, social, and economic benefits associated with cod recovery can be realised by novel changes, including quantitatively responsible recovery plans based on science-determined reference points, new or revised legislation, integrated management strategies, strengthened sustainable seafood certification practices, expansion of marine spatial planning and protected areas, and novel financial incentives for investment in long-term, sustainable fisheries.
News Article | September 14, 2016
In the Earth's oceans these days, the bigger a species is, the more prone it is to die off. That's unheard of in the long history of mass extinctions, a new study finds. As subfamilies of marine animal species — called genera — grow larger in body size, the likelihood of them being classified as threatened with extinction increases by an even greater amount, according to a study published Wednesday in the journal Science . In past extinctions, smaller creatures were more prone to die off, or size didn't matter, said study lead author Jonathan Payne, a paleobiologist at Stanford University. Almost none of the genera that have species averaging 0.4 inches (1 centimeter) long are threatened with extinction, But 23 percent of those that are 3.9 inches (10 centimeters) are threatened, 40 percent of those that are 39 inches (1 meter) are endangered and 86 percent of those that are 32.8 feet (10 meters) are vulnerable, Payne said. These are species that are not extinct yet, but are on the respected Red List of threatened and endangered species created by the International Union for the Conservation of Nature. "The proportion of species that are threatened increases enormously as body size increases," Payne said. Take the blue whale , not only the largest living animal, stretching close to 100 feet long, but the largest to ever have existed, Payne said. It's on the IUCN endangered list and has lost as much as 90 percent of its population in the last three generations, according to the IUCN. On the other end of the spectrum is a grouping of fish, bioluminescent bristlemouths , that are about three inches long. They are the most abundant creatures with a backbone; the population is estimated to be in the trillions. Payne compared fossil records, looked at past mass extinctions and compared them to current threats, concentrating on 264 genera that have the best modern and ancient records. Payne concentrated on oceans, where the fossil records are better over time. The mass extinction 65 million years ago that killed off the dinosaurs didn't kill off bigger marine species at higher rates than smaller ones, unlike what's happening now, Payne said. The study "shows us how unusual this crisis of biodiversity we have right now," said Boris Worm, a top marine scientist at Dalhousie University in Canada. He wasn't part of the study but praised it. "We have had mass extinctions before. This one is totally different than what has happened before." Worm spoke from a break during research in Canada's Bay of Fundy, where after a more-than-20-year career he finally saw his first underwater right whale and basking shark . "They are both in trouble and both among the largest of their kind," Worm said. Payne's study didn't try to explain why larger animals were more threatened, but both he and Worm point to one main suspect: humans. Mostly through fishing and hunting, but also through environmental degradation such as warmer and more acidic oceans, humans have made it tougher for the biggest marine animals to survive, they said. Catherine Novelli, the U.S. undersecretary of state for environment, said a world oceans conference that starts Thursday in Washington, will see the announcement of "many more" areas where nations set aside large areas of the seas where animals are protected and fishing is prohibited. Duke University biologist Stuart Pimm also praised the study as both compelling and disturbing because "even if some species do hang on, we have massively changed the ecology of much of the oceans." Payne said there is still hope, since these species haven't gone extinct yet. He points to northern elephant seals which had a population below 100 in the early 1910s, but are now more than 100,000 strong. But they are the exception. "It pains you to the core to know that these animals might be gone in a generation or two," Worm said. "You can't imagine a world without them. It's such an important and beautiful part of our planet."
News Article | February 23, 2017
HALIFAX, NOVA SCOTIA / ACCESSWIRE / February 23, 2017 / ELCORA ADVANCED MATERIALS CORP. (TSX-V:ERA / Frankfurt: ELM / OTCQB: ECORF) (the "Company" or "Elcora") is pleased to announce the appointment of Dr. Shane Beattie as the CTO of anode development with responsibilities in the technology, testing, manufacturing, and technical support of the Company's anode powder. Dr. Beattie has more than 15 years of experience in energy storage and anode development. He earned his Ph.D. working with Jeff Dahn at Dalhousie University. His Post Doctoral fellowship was with Dr. Jean-Marie Tarascon at the LRCS, UPJV, Amiens, France. More recently, he was the Technical Director at Warwick University's Battery Pilot Scale-up line. Dr. Beattie will be responsible for expanding the Company's existing capabilities to include testing of pouch cells, evaluating different graphite sources, supervision of the anode facility construction and related personnel, and interfacing with clients. He brings valuable experience working with several automotive companies using Li-ion technology and with cell manufacturers. "The appointment of Dr. Beattie facilitates the development of the anode powder aspect of Elcora's vertically integrated structure and brings battery anode manufacturing and testing knowledge into the Company," said Troy Grant, Elcora's President and CEO. In addition, "His experiences and knowledge of the industry will be key to help commercialize and sell the Elcora anode products." Elcora is pleased to report that they received $500,000 in non-repayable grants and $1,300,000 in Government Loans to assist with continued Lithium-Ion battery testing and development. In addition to the $1,800,000 amount, the Company announces that it has closed the second and final tranche of the non-brokered private placement financing (the "Private Placement") announced on January 31, 2017. The Private Placement closed at a total of $2,645,823 or 9,799,343 Units. The first tranche involved the issuance of 9,326,093 units ("Units") of the Company at a price of $0.27 per Unit for gross proceeds of $2,518,045. The final tranche involved the issuance of 473,250 Units of the Company at a price of $0.27 per Unit for gross proceeds of $127,778. Each Unit will be comprised of one common share and one common share purchase warrant. Each full warrant gives the holder the right to purchase one additional common share of Elcora at an exercise price of $0.34 for two years following the closing of the Private Placement. The term of the warrants may be accelerated in the event that the issuer's shares trade at or above a price of $0.60 cents per share for a period of 20 consecutive days. In such case of accelerated warrants, the issuer may give notice, in writing or by way of news release, to the subscribers that the warrants will expire 45 days from the date of providing such notice. In connection with the closing of both tranches of the Private Placement, the Company paid cash finders' fees equal to 6% of the proceeds and issued finders' shares equal to 6% of the number of Units sold. All securities issued pursuant to the Private Placement will be subject to a statutory four-month hold period. Elcora was founded in 2011 and has been structured to become a vertically integrated graphite and graphene company that mines, refines, and processes graphite, and produces graphene. The Company's products are then used to manufacture battery grade anode graphite and to develop future graphene based and/or enriched high tech products, such as graphene enhanced silicon anodes for lithium ion batteries. As part of this vertical integration strategy, Elcora has secured high-grade graphite and graphene precursor graphite from its interest in the operation of the Ragedara mine in Sri Lanka, which is already in production. Elcora has developed a unique low cost effective ecological processes to make high quality battery grade and battery form graphite and graphene at commercial scale. This combination means that Elcora has vertically integrated the tools and resources required to produce graphite, micro-graphite, and graphene. For further information, please visit the Company's website at http://www.elcoracorp.com. For further information please, contact: The TSX Venture Exchange does not accept responsibility for the adequacy or accuracy of this release. No stock Exchange, securities commission or other regulatory authority has approved or disapproved the information contained herein. This News Release includes certain "forward-looking statements." All statements other than statements of historical fact, included in this release, including, without limitation, statements regarding potential mineralization and reserves, exploration results, and future plans and objectives of Elcora, are forward-looking statements that involve various risks and uncertainties. There can be no assurance that such statements will prove to be accurate and actual results and future events could differ materially from those anticipated in such statements. Important factors that could cause actual results to differ materially from Elcora's expectations are exploration risks detailed herein and from time to time in the filings made by Elcora with securities regulators. Investors are cautioned that, except as disclosed in the filing statement prepared in connection with the transaction, any information released or received with respect to the transaction may not be accurate or complete and should not be relied upon.
News Article | October 29, 2016
Some fish species are adapting to survive environmental changes without significant genetic evolution, according to research from the University of East Anglia and Dalhousie University, Canada. Such changes mean species threatened by climate change may find ways to adapt far quicker than through changes in DNA, which come with evolution. Researchers studied the Winter Skate (Leucoraja ocellata), in waters that are around 7000 years old and significantly warmer than those where the rest of the species range is found. They observed many physical and functional adaptations which allow the species to cope with the significantly different set of environmental conditions observed in this shallow, warm habitat. Dr Jack Lighten from UEA's School of Environmental Sciences says this type of adaptation is due to epigenetic changes -- caused by modification of gene expression where instructions in DNA are converted into a functional product, i.e. protein. These adaptations are particularly important for species with long maturation times and low reproductive potential, as typically these life-history characteristics result in slow evolution. Rapid changes in gene expression, irrespective of changes in the DNA sequence, can allow rapid modification of an organisms biological characteristics and fuel a form of rapid adaptation. Dr Lighten said: "There is a wealth of fossil evidence which suggests rapid climate shifts don't provide enough opportunity for many species to adapt, meaning they became extinct or restricted to smaller areas of suitable habitat. "But adaptations in evolutionary potential through gene expression can enable species with long maturation and low reproductive output (and so low evolutionary potential) to survive and adapt to different environments -- something which may be vital for the future survival of sharks, skates, and rays in the light of future climate change." Skates formed the basis of the research because, despite low reproductive output and long maturation times meaning they are vulnerable to environmental change, they have persisted for more than 150 million years and two mass extinctions, suggesting they have a resilience and an evolutionary strategy allowing them to withstand environmental changes. Moreover, one of the populations is critically endangered and shows some interesting differences in appearance and eco-physiology compared to the rest of the species. Two populations of the Winter Skate in Atlantic Canada were studied -- one an endemic and endangered population in the southern Gulf of St Lawrence, and a large population on the Scotian Shelf. The southern Gulf populations is in a much shallower area, which sees summer water temperatures 10°C higher than on the Scotian Shelf, and it is estimated that this warmer habitat is just 7000 old. The southern Gulf of St. Lawrence Winter Skate has reduced its body size dramatically, by 45 per cent compared to those in the other population, and has a significantly shorter life span with a faster maturation time. Investigation of this miniaturized endemic skate's genes showed thousands of changes in gene expression. Dr Lighten said: "The Winter Skate has been able to adapt to a dramatically different environment over a short evolutionary time, with apparently little genetic change. These adaptive changes in life history, physiology and phenotype have occurred through epigenetic regulation causing changes in gene expression, enabling the species to respond rapidly to environmental challenges. "Comparisons with the population in the southern Gulf of St Lawrence showed more than 3600 changes in gene expression, which could be responsible for enabling the species to adapt to warmer shallower waters and the challenges that come with this." The importance of genetic versus epigenetic changes in adaptive evolution is hotly debated and the results of this study are significant in demonstrating the value of studying these variations, not only in fish but other species facing similar challenges. Dr Lighten said: "Because the southern Gulf of St. Lawrence is much shallower and warmer than other regions of the north west Atlantic, and species have only expanded their range into this region during the last seven thousand years or so after the last ice age, it may present a natural model system to test the effects of warmer oceans on marine biodiversity. Indeed we see miniaturization of other species in the Gulf compared to the remaining species range, and all other evidence suggests that this may similarly be due to higher water temperatures. "Our work suggests that some success of sharks, skates and rays over very long evolutionary time scales may be due to their ability to respond rapidly to environmental changes through regulation of gene expression. The biggest threat today for many of these species is overfishing. We are only just beginning to understand how they may be affected by climate change. We hope our findings will open the door for more detailed research on the role that epigenetics may play in allowing vulnerable and ecologically important fish to persist during this period of rapid global warming." The paper 'Adaptive phenotypic response to climate enabled by epigenetics in a K-strategy species, the fish Leucoraja ocellata (Rajidae)' is published in the journal Royal Society Open Science.
News Article | February 23, 2017
TORONTO, ON--(Marketwired - February 23, 2017) - Primero Mining Corp. ("Primero" or the "Company") (TSX: P) ( : PPP) announced today that Mr. Ernest Mast and Primero have reached a mutual decision that Mr. Mast will depart Primero to pursue other opportunities effective no later than March 6, 2017. Upon Mr. Mast's departure, Mr. Joseph F. Conway will be appointed Interim President and Chief Executive Officer. Mr. Mast will continue to assist the Company in facilitating a smooth transition in leadership. The Company thanks Mr. Mast for his service and his assistance in transitional matters. Mr. Conway is currently Vice Chairman and was previously President and C.E.O. of Primero from June 2010 through January 2016. Mr. Conway has nearly 30 years of mining and financial industry experience. He was President and C.E.O. of IAMGOLD Corporation from 2003 to 2010, growing it from a $50 million joint venture company to a $6 billion leading intermediate gold producer. Mr. Conway has a B.Sc. from Memorial University of Newfoundland (1981), and an MBA from Dalhousie University (1987). Primero Mining Corp. is a Canadian-based precious metals producer that owns 100% of the San Dimas gold-silver mine and the Cerro del Gallo gold-silver-copper development project in Mexico and 100% of the Black Fox mine and adjoining properties in the Township of Black River‐Matheson near Timmins, Ontario, Canada. Primero offers immediate exposure to un-hedged, below average cash cost gold production with a substantial resource base in politically stable jurisdictions. The Company is focused on becoming a leading intermediate gold producer by building a portfolio of high quality, low cost precious metals assets in the Americas.
News Article | October 26, 2016
Some fish species are adapting to survive environmental changes without significant genetic evolution, according to research from the University of East Anglia and Dalhousie University, Canada. Such changes mean species threatened by climate change may find ways to adapt far quicker than through changes in DNA, which come with evolution. Researchers studied the Winter Skate (Leucoraja ocellata), in waters that are around 7000 years old and significantly warmer than those where the rest of the species range is found. They observed many physical and functional adaptations which allow the species to cope with the significantly different set of environmental conditions observed in this shallow, warm habitat. Dr Jack Lighten from UEA's School of Environmental Sciences says this type of adaptation is due to epigenetic changes - caused by modification of gene expression where instructions in DNA are converted into a functional product, i.e. protein. These adaptations are particularly important for species with long maturation times and low reproductive potential, as typically these life-history characteristics result in slow evolution. Rapid changes in gene expression, irrespective of changes in the DNA sequence, can allow rapid modification of an organisms biological characteristics and fuel a form of rapid adaptation. Dr Lighten said: "There is a wealth of fossil evidence which suggests rapid climate shifts don't provide enough opportunity for many species to adapt, meaning they became extinct or restricted to smaller areas of suitable habitat. "But adaptations in evolutionary potential through gene expression can enable species with long maturation and low reproductive output (and so low evolutionary potential) to survive and adapt to different environments - something which may be vital for the future survival of sharks, skates, and rays in the light of future climate change." Skates formed the basis of the research because, despite low reproductive output and long maturation times meaning they are vulnerable to environmental change, they have persisted for more than 150 million years and two mass extinctions, suggesting they have a resilience and an evolutionary strategy allowing them to withstand environmental changes. Moreover, one of the populations is critically endangered and shows some interesting differences in appearance and eco-physiology compared to the rest of the species. Two populations of the Winter Skate in Atlantic Canada were studied - one an endemic and endangered population in the southern Gulf of St Lawrence, and a large population on the Scotian Shelf. The southern Gulf populations is in a much shallower area, which sees summer water temperatures 10°C higher than on the Scotian Shelf, and it is estimated that this warmer habitat is just 7000 old. The southern Gulf of St. Lawrence Winter Skate has reduced its body size dramatically, by 45 per cent compared to those in the other population, and has a significantly shorter life span with a faster maturation time. Investigation of this miniaturized endemic skate's genes showed thousands of changes in gene expression. Dr Lighten said: "The Winter Skate has been able to adapt to a dramatically different environment over a short evolutionary time, with apparently little genetic change. These adaptive changes in life history, physiology and phenotype have occurred through epigenetic regulation causing changes in gene expression, enabling the species to respond rapidly to environmental challenges. "Comparisons with the population in the southern Gulf of St Lawrence showed more than 3600 changes in gene expression, which could be responsible for enabling the species to adapt to warmer shallower waters and the challenges that come with this." The importance of genetic versus epigenetic changes in adaptive evolution is hotly debated and the results of this study are significant in demonstrating the value of studying these variations, not only in fish but other species facing similar challenges. Dr Lighten said: "Because the southern Gulf of St. Lawrence is much shallower and warmer than other regions of the north west Atlantic, and species have only expanded their range into this region during the last seven thousand years or so after the last ice age, it may present a natural model system to test the effects of warmer oceans on marine biodiversity. Indeed we see miniaturization of other species in the Gulf compared to the remaining species range, and all other evidence suggests that this may similarly be due to higher water temperatures. "Our work suggests that some success of sharks, skates and rays over very long evolutionary time scales may be due to their ability to respond rapidly to environmental changes through regulation of gene expression. The biggest threat today for many of these species is overfishing. We are only just beginning to understand how they may be affected by climate change. We hope our findings will open the door for more detailed research on the role that epigenetics may play in allowing vulnerable and ecologically important fish to persist during this period of rapid global warming." The paper 'Adaptive phenotypic response to climate enabled by epigenetics in a K-strategy species, the fish Leucoraja ocellata (Rajidae)' is published in the journal Royal Society Open Science.
News Article | November 16, 2016
It takes a village to raise a whale. Rather than sticking exclusively to their mothers’ side, baby pilot whales in the north Atlantic take turns swimming next to other adults – including both females and males. Pilot whales are social creatures. They are thought to live in multigenerational family units of about two to four dozen individuals, says Joana Augusto at Dalhousie University in Halifax, Canada. Those units often gather in larger groups that stay together for up to a few weeks, allowing whales to travel, feed, rest and socialise together. And while anecdotal evidence suggests calves sometimes accompany members of the gang that aren’t their mothers, nobody had systematically studied the behaviour in pilot whales before, Augusto says. “People have noticed that the calves didn’t really stay with the same adults,” she says. “We would see the babies just go from one individual to the other and then jump back.” To see if this behaviour is common among the population of more than 3000 long-finned pilot whales that spend the summer off Cape Breton Island in Nova Scotia, Canada, Augusto and her colleagues tagged along on a whale-watching boat. From the vessel, the researchers photographed and identified specific whales based on physical marks such as nicks in their dorsal fins, scars and pigmentation patterns. During more than 600 whale encounters over three years, the team spotted 356 identifiable calves, about one fourth of which sometimes stuck close to an adult that wasn’t their mother. One baby took turns swimming beside five grown-up companions. Using a foam-tipped dart and a crossbow, the scientists collected DNA samples from 75 adult whales to determine their sex. Only five of those adults were identified as non-maternal calf companions — and of those, four were male. That was a surprise, Augusto says. It is unclear why a male might let a baby stay by his side, but one possibility is that he is showing off in front of the females. “It’s a way to advertise that they’re a good mate, basically,” Augusto says. The scientists didn’t notice the adults altering their behaviour when they had a young companion. That could enable the calf to observe the complex social conventions of their community, Augusto says. “The calf might be learning from experiences with different individuals of how they should be behaving socially,” she says. Shared parenting is something you would expect in a species with such strong social bonds, says Robin Baird at the Cascadia Research Collective in Olympia, Washington state. Bottlenose dolphins and killer whales sometimes escort others’ calves, for example, and sperm whales and belugas even nurse others’ babies, strengthening the social ties of the group, or perhaps signalling to other adults that the babysitters are pulling their weight in the community. It will be interesting to gather more details on the nature of the interactions between pilot whale calves and adults, Baird says, like how long they spend side by side, and the age of the adult male companions. If the males are relatively young, for example, they may be seeking playmates rather than pupils. Still, Baird says, it is highly likely that calves are soaking up social understanding during the encounters. “Calves are gregarious,” he says. “Calves are motivated to interact with other individuals when their mom’s not right around them.” Read more: Post-menopausal orcas’ wisdom helps family survive; Orcas are first non-humans whose evolution is driven by culture
News Article | February 23, 2017
Dr. Beattie has more than 15 years of experience in energy storage and anode development. He earned his Ph.D. working with Jeff Dahn at Dalhousie University. His Post Doctoral fellowship was with Dr. Jean-Marie Tarascon at the LRCS, UPJV, Amiens, France. More recently, he was the Technical Director at Warwick University's Battery Pilot Scale-up line. Dr. Beattie will be responsible for expanding the Company's existing capabilities to include testing of pouch cells, evaluating different graphite sources, supervision of the anode facility construction and related personnel, and interfacing with clients. He brings valuable experience working with several automotive companies using Li-ion technology and with cell manufacturers. "The appointment of Dr. Beattie facilitates the development of the anode powder aspect of Elcora's vertically integrated structure and brings battery anode manufacturing and testing knowledge into the Company," said Troy Grant, Elcora's President and CEO. In addition, "His experiences and knowledge of the industry will be key to help commercialize and sell the Elcora anode products." Elcora is pleased to report that they received $500,000 in non-repayable grants and $1,300,000 in Government Loans to assist with continued Lithium-Ion battery testing and development. In addition to the $1,800,000 amount, the Company announces that it has closed the second and final tranche of the non-brokered private placement financing (the "Private Placement") announced on January 31, 2017. The Private Placement closed at a total of $2,645,823 or 9,799,343 Units. The first tranche involved the issuance of 9,326,093 units ("Units") of the Company at a price of $0.27 per Unit for gross proceeds of $2,518,045. The final tranche involved the issuance of 473,250 Units of the Company at a price of $0.27 per Unit for gross proceeds of $127,778. Each Unit will be comprised of one common share and one common share purchase warrant. Each full warrant gives the holder the right to purchase one additional common share of Elcora at an exercise price of $0.34 for two years following the closing of the Private Placement. The term of the warrants may be accelerated in the event that the issuer's shares trade at or above a price of $0.60 cents per share for a period of 20 consecutive days. In such case of accelerated warrants, the issuer may give notice, in writing or by way of news release, to the subscribers that the warrants will expire 45 days from the date of providing such notice. In connection with the closing of both tranches of the Private Placement, the Company paid cash finders' fees equal to 6% of the proceeds and issued finders' shares equal to 6% of the number of Units sold. All securities issued pursuant to the Private Placement will be subject to a statutory four-month hold period. Elcora was founded in 2011 and has been structured to become a vertically integrated graphite and graphene company that mines, refines, and processes graphite, and produces graphene. The Company's products are then used to manufacture battery grade anode graphite and to develop future graphene based and/or enriched high tech products, such as graphene enhanced silicon anodes for lithium ion batteries. As part of this vertical integration strategy, Elcora has secured high-grade graphite and graphene precursor graphite from its interest in the operation of the Ragedara mine in Sri Lanka, which is already in production. Elcora has developed a unique low cost effective ecological processes to make high quality battery grade and battery form graphite and graphene at commercial scale. This combination means that Elcora has vertically integrated the tools and resources required to produce graphite, micro-graphite, and graphene. For further information, please visit the Company's website at http://www.elcoracorp.com. For further information please, contact: The TSX Venture Exchange does not accept responsibility for the adequacy or accuracy of this release. No stock Exchange, securities commission or other regulatory authority has approved or disapproved the information contained herein. This News Release includes certain "forward-looking statements." All statements other than statements of historical fact, included in this release, including, without limitation, statements regarding potential mineralization and reserves, exploration results, and future plans and objectives of Elcora, are forward-looking statements that involve various risks and uncertainties. There can be no assurance that such statements will prove to be accurate and actual results and future events could differ materially from those anticipated in such statements. Important factors that could cause actual results to differ materially from Elcora's expectations are exploration risks detailed herein and from time to time in the filings made by Elcora with securities regulators. Investors are cautioned that, except as disclosed in the filing statement prepared in connection with the transaction, any information released or received with respect to the transaction may not be accurate or complete and should not be relied upon.
News Article | February 16, 2017
Doctors on Liens is proud to announce the addition of the highly regarded orthopedic surgeon, Dr. Raj, to their network through his work at BKP Chiropractic in Lancaster. After receiving his undergraduate degree in Chemistry from Dalhousie University, and his medical degree from Canada’s prestigious International Baccalaureate Program, Dr. Raj went on to open successful orthopedic practices in both Beverly Hills and Dubai. Now, with more than 4000 cases under his belt, Dr. Raj is thrilled to bring his wealth of knowledge and experience to the residents of Lancaster. As one of the area’s top orthopedic surgeons, Dr. Raj provides the ultimate in state of the art, quality orthopedic care available, and is always striving to provide his patients with the most up-to-date technologies available. Dr. Raj believes that an important part of recovery starts before treatment, with educating the patient and their family members on all treatment options, both invasive and non-invasive. Along with his medical expertise, Dr. Raj is also an avid volunteer in his community and is a proud member of Iraq Star, which provides necessary treatment to approximately 40,000 veterans returning from wars in Iraq and Afghanistan. Dr. Raj’s obsession for perfection has led to unparalleled surgical results and an impeccable reputation which has garnered the attention of media seeking his expert opinion, including many guest appearances on radio and television programs. In addition, he has been featured on the “Best of LA” and has received numerous other accolades and awards including being named one of "America's Top Orthopedic Surgeons" five years in a row and Super Doctors Southern California for the past three years. Says Doctors on Liens President Samantha Parker, “For more than twenty years, Doctors on Liens has prided itself in finding the best doctors the medical community has to offer, and Dr. Raj exemplifies that goal. I know BKP Chiropractic is as thrilled as I am to be working with a man of Dr. Raj’s stature.” Doctors on Liens is an innovator in the medical lien specialty referral industry and has forged close relationships with both legal firms and medical practices over the past 20 years. Doctors on Liens features medical specialties including board certified orthopedic surgeons, neurologists, general practitioners, psychologists, and chiropractors. Each medical office is independently owned and operated and all appointments can be conveniently scheduled directly with the facility. Doctors on Liens lists medical professionals who offer medical services on a lien basis throughout California and Nevada.
News Article | December 14, 2016
MONTREAL, QUEBEC--(Marketwired - Dec. 14, 2016) - Genius Properties Ltd. (CSE:GNI) ("Genius" or the "Corporation") is pleased to announce that the due diligence period for Mt. Cameron acquisition has been extended to December 31st 2016. The Property is conveniently located 25 kilometers west of Sydney, Nova Scotia and is comprised of 7 licenses (82 claims over 13.3 km2). In regards to infrastructure, the property is easily accessible by paved roads and is in close proximity of an electric utility. With the potential construction of NOVAPORT, a deep-water mega-terminal in Sydney, trans-Atlantic shipping would be readily available; moreover, having an extensive history in steel manufacturing and coal mining, Sydney has a highly skilled workforce to offer. The mineralization on the Property is flake graphite in marble of the George River formation and has been identified along a strike length of approximately 12 km with zones up to 1.5 km wide and interpreted to be up to 300 m deep. Mt. Cameron has carried out prospecting, drilling and geophysics on the Property; all of which indicate an extensive mineralized zone. Preliminary mineral processing studies have been carried out by Dr. Ian Flint, former Director of the Minerals Engineering Center at Dalhousie University in Halifax. Jimmy Gravel, the President and CEO of the Corporation stated: "The due diligence for Mt. Cameron is moving forward nicely and I feel very confident that we can finalize all the details before the New Year". Genius is a Canadian mineral exploration company focused on developing projects with some of the world's most critical metals and minerals for use in various industries including in particular, batteries for storing electrical energy and the raw materials essential for Lithium-ion battery production This news release contains forward-looking information within the meaning of applicable Canadian securities laws. All information other than historical fact is forward-looking information. Forward-looking information relates to future events or future performance and is based on GNI current internal expectations, estimates, projections, assumptions and beliefs. Forward-looking information is often, but not always, identified by the use of words such as "expect", "project", "proposed", "intend", "seek", "anticipate", "budget", "plan", "continue", "estimate", "forecast", "may", "will", "predict", "potential", "targeting", "could", "might", "should", "believe" and similar expressions. Although management considers the assumptions and estimates, reflected in forward-looking information, to be reasonable, based on information currently available, there can be no assurance that such information will prove to be correct. As a consequence, actual results may differ materially from those anticipated. Undue reliance should not be placed on forward-looking information which is inherently uncertain, and subject to known and unknown risks and uncertainties (both general and specific) and other factors that contribute to the possibility that the future events or circumstances contemplated by the forward looking information will not occur or that may cause the actual results, level of activity, performance or achievements of the Company to be materially different from those expressed or implied by such forward-looking information. These risks include, but are not limited to risks associated with general economic conditions, the actual results of current exploration activities, conclusions of economic evaluations, changes in project parameters as plans continue to be refined, future metal prices, financial risks and substantial capital requirements. Further information regarding certain of these risks (as well as risks relating generally to the Company's business) may be found under the headings "Risks and Uncertainties", "Forward-Looking Information" and "Financial risk factors" in the latest Company's Management's Discussion & Analysis on www.sedar.com. Readers are cautioned that the foregoing list of factors that may affect future results is not exhaustive. The forward-looking statements contained in this news release are made as of the date hereof and GNI does not undertake any obligation to update publicly or to revise any of the included forward-looking statements, except as required by applicable law. The forward-looking statements contained herein are expressly qualified by this cautionary statement. Neither the CSE nor its Regulation Services Provider accepts responsibility for the adequacy or accuracy of this release.
News Article | October 7, 2016
Researchers have confirmed the existence of a naturally occurring exotic property in which a material becomes thicker when stretched - the opposite of most materials - a discovery that could lead to new studies into the fundamental science of nano-materials behavior. The counterintuitive phenomenon, called auxetic behavior, has been extensively studied in engineered structures that have potential applications in medicine, tissue engineering, body armor and "fortified armor enhancement." However, until now the behavior has not been confirmed in natural materials, said Peide Ye, Purdue University's Richard J. and Mary Jo Schwartz Professor of Electrical and Computer Engineering. The auxetic behavior was discovered in a material called black phosphorous. The phenomenon is governed by a fundamental mechanical property of materials called the Poisson's ratio, which characterizes how a material behaves when stretched. Most materials when stretched become thinner and when compressed become thicker, and they are said to have a positive Poisson's ratio. "A negative Poisson's ratio is theoretically possible but until now has not, with few exceptions of man-made structures, been experimentally observed in any natural materials," Ye said. "Here, we show that the negative Poisson's ratio exists in the natural material black phosphorus." Findings are detailed in a research paper that appeared on Sept. 23 in the journal Nano Letters. "Until now, there has been a lack of experimental evidence since the measurement of internal deformation in auxetic materials, in particular at the atomic level, is extremely difficult," Ye said. Researchers used a technique called Raman spectroscopy to document the negative Poisson's ratio in extremely thin, individual layers of black phosphorous called phosphorene. The research was based at the Birck Nanotechnology Center in Purdue's Discovery Park. The Nano Letters paper was authored by doctoral student Yuchen Du; former postdoctoral research associate Jesse Maassen; graduate students Wangran Wu and Zhe Luo; Xianfan Xu, the James J. and Carol L. Shuttleworth Professor of Mechanical Engineering and professor of electrical and computer engineering; and Ye. Du carried out most of the experiments. Maassen performed the theoretical work critical to the research. He is now an assistant professor of physics at Dalhousie University in Nova Scotia, Canada. The researchers focused on the material's uniquely puckered crystal structure in which atoms are arranged in a wavy pattern. Like silicon, the material possesses a bandgap, a trait essential for a semiconductor's ability to switch on and off in electronic circuits. The material also has a relatively high "carrier mobility," meaning it is very conductive and could be useful for technological applications. Future research will include work to investigate whether the negative Poisson's ratio exists in other so-called "two-dimensional" materials, including extremely thin layers of graphite called graphene.
News Article | October 7, 2016
Home > Press > Exotic property confirmed in natural material could lead to fundamental studies Abstract: Auxetic Black Phosphorus: A 2D Material with Negative Poisson's Ratio Yuchen Du1,3, Jesse Maassen1,3,4,*, Wangran Wu1,3, Zhe Luo2,3, Xianfan Xu2,3,*, and Peide D. Ye1,3,* 1 School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 2 School of Mechanical Engineering, Purdue University 3 Birck Nanotechnology Center, Purdue University 4 Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia, Canada, * Address correspondence to: (P.D.Y.); (X.X.); (J.M.) The Poisson's ratio of a material characterizes its response to uniaxial strain. Materials normally possess a positive Poisson's ratio - they contract laterally when stretched, and expand laterally when compressed. A negative Poisson's ratio is theoretically permissible but has not, with few exceptions of man-made bulk structures, been experimentally observed in any natural materials. Here, we show that the negative Poisson's ratio exists in the low-dimensional natural material black phosphorus, and that our experimental observations are consistent with first principles simulations. Through applying uniaxial strain along armchair direction, we have succeeded in demonstrating a cross-plane interlayer negative Poisson's ratio on black phosphorus for the first time. Meanwhile, our results support the existence of a cross-plane intralayer negative Poisson's ratio in the constituent phosphorene layers under uniaxial deformation along the zigzag axis, which is in line with a previous theoretical prediction. The phenomenon originates from the puckered structure of its in-plane lattice, together with coupled hinge-like bonding configurations. Researchers have confirmed the existence of a naturally occurring exotic property in which a material becomes thicker when stretched - the opposite of most materials - a discovery that could lead to new studies into the fundamental science of nano-materials behavior. The counterintuitive phenomenon, called auxetic behavior, has been extensively studied in engineered structures that have potential applications in medicine, tissue engineering, body armor and "fortified armor enhancement." However, until now the behavior has not been confirmed in natural materials, said Peide Ye, Purdue University's Richard J. and Mary Jo Schwartz Professor of Electrical and Computer Engineering. The auxetic behavior was discovered in a material called black phosphorous. The phenomenon is governed by a fundamental mechanical property of materials called the Poisson's ratio, which characterizes how a material behaves when stretched. Most materials when stretched become thinner and when compressed become thicker, and they are said to have a positive Poisson's ratio. "A negative Poisson's ratio is theoretically possible but until now has not, with few exceptions of man-made structures, been experimentally observed in any natural materials," Ye said. "Here, we show that the negative Poisson's ratio exists in the natural material black phosphorus." Findings are detailed in a research paper that appeared on Sept. 23 in the journal Nano Letters. "Until now, there has been a lack of experimental evidence since the measurement of internal deformation in auxetic materials, in particular at the atomic level, is extremely difficult," Ye said. Researchers used a technique called Raman spectroscopy to document the negative Poisson's ratio in extremely thin, individual layers of black phosphorous called phosphorene. The research was based at the Birck Nanotechnology Center in Purdue's Discovery Park. The Nano Letters paper was authored by doctoral student Yuchen Du; former postdoctoral research associate Jesse Maassen; graduate students Wangran Wu and Zhe Luo; Xianfan Xu, the James J. and Carol L. Shuttleworth Professor of Mechanical Engineering and professor of electrical and computer engineering; and Ye. Du carried out most of the experiments. Maassen performed the theoretical work critical to the research. He is now an assistant professor of physics at Dalhousie University in Nova Scotia, Canada. The researchers focused on the material's uniquely puckered crystal structure in which atoms are arranged in a wavy pattern. Like silicon, the material possesses a bandgap, a trait essential for a semiconductor's ability to switch on and off in electronic circuits. The material also has a relatively high "carrier mobility," meaning it is very conductive and could be useful for technological applications. Future research will include work to investigate whether the negative Poisson's ratio exists in other so-called "two-dimensional" materials, including extremely thin layers of graphite called graphene. The research was funded by the National Science Foundation, U.S. Air Force Office of Scientific Research, the U.S. Army Research Office, and the Natural Sciences and Engineering Research Council of Canada. For more information, please click If you have a comment, please us. Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.
Steinbring E.,National Research Council Canada |
Ward W.,University of New Brunswick |
Drummond J.R.,Dalhousie University
Publications of the Astronomical Society of the Pacific | Year: 2012
Nighttime visible-light sky brightness and transparency are reported for the Polar Environment Research Laboratory (PEARL), located on a 610 m high ridge near the Eureka research station at 80° latitude, on Ellesmere Island, Canada. Photometry of Polaris obtained in the V band with the PEARL All Sky Imager (PASI) over two winters is supported by standard meteorological measurements and visual estimates of sky conditions from sea level. These data show that during the period of the study, 2008/2009 and 2009/2010 October through March, the sky near zenith had a mean surface brightness of 19:7 mag arcsec -2 when the Sun was more than 12° below the horizon, reaching 20:7 mag arcsec -2 during astronomical darkness with no Moon. Skies were without thick cloud and potentially usable for astronomy 86% of the time (extinction <2 mag). Up to 68% of the time was spectroscopic (≤0:5 mag), attenuated by ice crystals, or clear with stable atmospheric transparency. Those conditions can persist for over 100 hr at a time. Further analysis suggests the sky was entirely free of ice crystals (truly photometric) 48 ± 3% of the time at PEARL in winter and that a higher elevation location nearby may be better. © 2012. The Astronomical Society of the Pacific.
Wiacek A.,Dalhousie University |
Peter T.,ETH Zurich |
Lohmann U.,ETH Zurich
Atmospheric Chemistry and Physics | Year: 2010
This modelling study explores the availability of mineral dust particles as ice nuclei for interactions with ice, mixed-phase and liquid water clouds, also tracking the particles' history of cloud-processing. We performed 61 320 one-week forward trajectory calculations originating near the surface of major dust emitting regions in Africa and Asia using high-resolution meteorological analysis fields for the year 2007. Dust-bearing trajectories were assumed to be those coinciding with known dust emission seasons, without explicitly modelling dust emission and deposition processes. We found that dust emissions from Asian deserts lead to a higher potential for interactions with high ice clouds, despite being the climatologically much smaller dust emission source. This is due to Asian regions experiencing significantly more ascent than African regions, with strongest ascent in the Asian Taklimakan desert at ∼25%, ∼40% and 10% of trajectories ascending to 300 hPa in spring, summer and fall, respectively. The specific humidity at each trajectory's starting point was transported in a Lagrangian manner and relative humidities with respect to water and ice were calculated in 6-h steps downstream, allowing us to estimate the formation of liquid, mixed-phase and ice clouds. Downstream of the investigated dust sources, practically none of the simulated air parcels reached conditions of homogeneous ice nucleation (T≲-40 °C) along trajectories that have not experienced water saturation first. By far the largest fraction of cloud forming trajectories entered conditions of mixed-phase clouds, where mineral dust will potentially exert the biggest influence. The majority of trajectories also passed through atmospheric regions supersaturated with respect to ice but subsaturated with respect to water, where so-called "warm ice clouds" (T≲-40 °C) theoretically may form prior to supercooled water or mixed-phase clouds. The importance of "warm ice clouds" and the general influence of dust in the mixed-phase cloud region are highly uncertain due to both a considerable scatter in recent laboratory data from ice nucleation experiments, which we briefly review in this work, and due to uncertainties in sub-grid scale vertical transport processes unresolved by the present trajectory analysis. For "classical" cirrus-forming temperatures (T≲-40 °C), our results show that only mineral dust ice nuclei that underwent mixed-phase cloud-processing, most likely acquiring coatings of organic or inorganic material, are likely to be relevant. While the potential paucity of deposition ice nuclei shown in this work dimishes the possibility of deposition nucleation, the absence of liquid water droplets at T≲-40 °C makes the less explored contact freezing mechanism (involving droplet collisions with bare ice nuclei) highly inefficient. These factors together indicate the necessity of further systematic studies of immersion mode ice nucleation on mineral dust suspended in atmospherically relevant coatings. © 2010 Author(s).
Lefort E.C.,Dalhousie University |
Blay J.,University of Waterloo
Molecular Nutrition and Food Research | Year: 2013
Apigenin (4′,5,7-trihydroxyflavone, 5,7-dihydroxy-2-(4-hydroxyphenyl)-4H-1-benzopyran-4-one) is a flavonoid found in many fruits, vegetables, and herbs, the most abundant sources being the leafy herb parsley and dried flowers of chamomile. Present in dietary sources as a glycoside, it is cleaved in the gastrointestinal lumen to be absorbed and distributed as apigenin itself. For this reason, the epithelium of the gastrointestinal tract is exposed to higher concentrations of apigenin than tissues at other locations. This would also be true for epithelial cancers of the gastrointestinal tract. We consider the evidence for actions of apigenin that might hinder the ability of gastrointestinal cancers to progress and spread. Apigenin has been shown to inhibit cell growth, sensitize cancer cells to elimination by apoptosis, and hinder the development of blood vessels to serve the growing tumor. It also has actions that alter the relationship of the cancer cells with their microenvironment. Apigenin is able to reduce cancer cell glucose uptake, inhibit remodeling of the extracellular matrix, inhibit cell adhesion molecules that participate in cancer progression, and oppose chemokine signaling pathways that direct the course of metastasis into other locations. As such, apigenin may provide some additional benefit beyond existing drugs in slowing the emergence of metastatic disease. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Sterling S.M.,Dalhousie University |
Sterling S.M.,University Pierre and Marie Curie |
Ducharne A.,University Pierre and Marie Curie |
Polcher J.,University Pierre and Marie Curie
Nature Climate Change | Year: 2013
Floods and droughts cause perhaps the most human suffering of all climate-related events; a major goal is to understand how humans alter the incidence and severity of these events by changing the terrestrial water cycle. Here we use over 1,500 estimates of annual evapotranspiration and a database of global land-cover change to project alterations of global scale terrestrial evapotranspiration (TET) from current anthropogenic land-cover change. Geographic modelling reveals that land-cover change reduces annual TET by approximately 3,500 km 3 yr -1 (5%) and that the largest changes in evapotranspiration are associated with wetlands and reservoirs. Land surface model simulations support these evapotranspiration changes, and project increased runoff (7.6%) as a result of land-cover changes. Next we create a synthesis of the major anthropogenic impacts on annual runoff and find that the net result is an increase in annual runoff, although this is uncertain. The results demonstrate that land-cover change alters annual global runoff to a similar or greater extent than other major drivers, affirming the important role of land-cover change in the Earth System. Last, we identify which major anthropogenic drivers to runoff change have a mean global change statistic that masks large regional increases and decreases: land-cover change, changes in meteorological forcing, and direct CO 2 effects on plants. © 2013 Macmillan Publishers Limited. All rights reserved.
Albertz M.,ExxonMobil |
Albertz M.,Dalhousie University |
Beaumont C.,Dalhousie University
Tectonics | Year: 2010
Having established the first-order controls of the three primary salt tectonic structural styles of the Scotian Basin in paper 1, in this paper (paper 2) we investigate and show that many unexplained structures can be attributed to more complex initial geometries of the autochthonous salt basins than the simple rectangular shapes used in paper 1. Basement highs modify and reduce the efficiency of salt evacuation during sediment aggradation followed by progradation. Low-angle taper (∼3°) of the basin edge slows Poiseuille flow and allows for trapping of salt beneath distal salt sheets. Seaward basement step ups do not necessarily hinder salt flow, and basement step downs can localize diapirs. Midbasin salt sheets can emerge when basement blocks as high as the salt is thick divide a basin into two subbasins. Deep salt basins that form above basement lows are efficiently evacuated. Weak overburden sediments augment the formation of salt sheets. © 2010 by the American Geophysical Union.
Azagba S.,University of Waterloo |
Langille D.,Dalhousie University |
Asbridge M.,Dalhousie University
Preventive Medicine | Year: 2014
Objective: To examine the prevalence, patterns, and correlates of energy drink use among adolescents, and determine whether more frequent use of energy drinks is associated with poorer health and behavioral outcomes. Methods: Data were from a 2012 cross-sectional survey of 8210 students in grades 7, 9, 10 and 12 attending public schools in Atlantic Canada. Multinomial logistic regression analysis was used to examine correlates of energy drink use patterns, including substance use, sensation seeking, risk of depression, and socioeconomic status. Results: Nearly two-thirds of survey respondents (62%) reported consuming energy drinks at least once in the previous year, with about 20% reporting use once or more per month. Sensation seeking, depression, and substance use were all higher among energy drink users relative to non-users, and in higher frequency users relative to lower frequency users. Conclusions: The prevalence of energy drink consumption among high school students was high. The association of energy drinks with other potential negative health and behavioral outcomes suggests that use of these products may represent a marker for other activities that may negatively affect adolescent development, health and well-being. © 2014 Elsevier Inc.
Mora C.,Dalhousie University |
Mora C.,University of Hawaii at Manoa |
Tittensor D.P.,Dalhousie University |
Tittensor D.P.,United Nations Environment Programme World Conservation Monitoring Center |
And 4 more authors.
PLoS Biology | Year: 2011
The diversity of life is one of the most striking aspects of our planet; hence knowing how many species inhabit Earth is among the most fundamental questions in science. Yet the answer to this question remains enigmatic, as efforts to sample the world's biodiversity to date have been limited and thus have precluded direct quantification of global species richness, and because indirect estimates rely on assumptions that have proven highly controversial. Here we show that the higher taxonomic classification of species (i.e., the assignment of species to phylum, class, order, family, and genus) follows a consistent and predictable pattern from which the total number of species in a taxonomic group can be estimated. This approach was validated against well-known taxa, and when applied to all domains of life, it predicts ~8.7 million (±1.3 million SE) eukaryotic species globally, of which ~2.2 million (±0.18 million SE) are marine. In spite of 250 years of taxonomic classification and over 1.2 million species already catalogued in a central database, our results suggest that some 86% of existing species on Earth and 91% of species in the ocean still await description. Renewed interest in further exploration and taxonomy is required if this significant gap in our knowledge of life on Earth is to be closed. © 2011 Mora et al.
Moreside J.M.,Dalhousie University |
Mcgill S.M.,University of Waterloo
Journal of Strength and Conditioning Research | Year: 2013
The purpose of this study was to analyze the transference of increased passive hip range of motion (ROM) and core endurance to functional movement. Twenty-four healthy young men with limited hip mobility were randomly assigned to 4 intervention groups: group 1, stretching; group 2, stretching plus hip/spine disassociation exercises; group 3, core endurance; and group 4, control. Previous work has documented the large increase in passive ROM and core endurance that was attained over the 6-week interventions, but whether these changes transferred to functional activities was unclear. Four dynamic activities were analyzed before and after the 6-week interventions: active standing hip extension, lunge, a standing twist/reach maneuver, and exercising on an elliptical trainer. A Vicon motion capture system collected body segment kinematics, with hip and lumbar spine angles subsequently calculated in Visual 3D. Repeated measures analyses of variance determined group effects on various hip and spine angles, with paired t-tests on specific pre/post pairs. Despite the large increases in passive hip ROM, there was no evidence of increased hip ROM used during functional movement testing. Similarly, the only significant change in lumbar motion was a reduction in lumbar rotation during the active hip extension maneuver (p , 0.05). These results indicate that changes in passive ROM or core endurance do not automatically transfer to changes in functional movement patterns. This implies that training and rehabilitation programs may benefit from an additional focus on "grooving" new motor patterns if newfound movement range is to be used.©2013 National Strength and Conditioning Association.
Camfield C.S.,Dalhousie University |
Striano P.,University of Genoa |
Camfield P.R.,Dalhousie University
Epilepsy and Behavior | Year: 2013
Juvenile myoclonic epilepsy (JME) is a widely recognized presumed genetic, electroclinical idiopathic generalized epilepsy syndrome. The prevalence of JME in large cohorts has been estimated to be 5% to 10% of all epilepsies and around 18% of idiopathic generalized epilepsies but may be lower in some settings. There is a marked female predominance. However, some of the basic epidemiology of JME is not well known, possibly because the syndrome is not sharply defined. A questionnaire study about the diagnostic criteria for JME suggests that diagnosis of JME can be made with the history of myoclonus plus a single generalized tonic-clonic seizure plus generalized fast spike-waves or polyspike-waves on the EEG. However, until these diagnostic criteria are fully accepted, the detailed epidemiology of JME will remain imprecise. © 2012 Elsevier Inc.
Yeates P.,University of Manchester |
O'Neill P.,University of Manchester |
Mann K.,Dalhousie University |
Eva K.,University of British Columbia
Advances in Health Sciences Education | Year: 2013
Assessors' scores in performance assessments are known to be highly variable. Attempted improvements through training or rating format have achieved minimal gains. The mechanisms that contribute to variability in assessors' scoring remain unclear. This study investigated these mechanisms. We used a qualitative approach to study assessors' judgements whilst they observed common simulated videoed performances of junior doctors obtaining clinical histories. Assessors commented concurrently and retrospectively on performances, provided scores and follow-up interviews. Data were analysed using principles of grounded theory. We developed three themes that help to explain how variability arises: Differential Salience-assessors paid attention to (or valued) different aspects of the performances to different degrees; Criterion Uncertainty-assessors' criteria were differently constructed, uncertain, and were influenced by recent exemplars; Information Integration-assessors described the valence of their comments in their own unique narrative terms, usually forming global impressions. Our results (whilst not precluding the operation of established biases) describe mechanisms by which assessors' judgements become meaningfully-different or unique. Our results have theoretical relevance to understanding the formative educational messages that performance assessments provide. They give insight relevant to assessor training, assessors' ability to be observationally "objective" and to the educational value of narrative comments (in contrast to numerical ratings). © 2012 Springer Science+Business Media B.V.
Eddy T.D.,WWF New Zealand Aotearoa |
Eddy T.D.,Dalhousie University
Marine Policy | Year: 2014
Anthropogenic threats to the global marine environment are increasing, and the Convention of Biological Diversity has set a target of 10% global ocean protection by 2020. Social factors are an important component of coastal marine protected area and no-take marine reserve creation. In order to understand social factors influencing marine reserve creation in New Zealand, public surveys were conducted in 2005 and 2011 about marine protection and threats to the marine environment (Territorial Sea and Exclusive Economic Zone). These results are compared to an experts' opinion survey of threats to the New Zealand marine environment, and actual marine protection levels. Generally, the New Zealand public identified similar New Zealand originated threats to the marine environment as those identified by experts, in contrast to expert identified global threats originating from climate change, which were minimally identified by the public. Experts identified that shallow, coastal waters were under greater threat than deep water habitats. On average, the New Zealand public thought that ~30% of New Zealand's marine environment was protected by no-take marine reserves, and that 36% should be protected, while in fact only 0.3% is protected by no-take marine reserves. There is considerable potential for publicly driven marine protection initiatives in New Zealand with sufficient awareness, education, and outreach programs to better inform New Zealanders about actual marine protection levels. The results of this study are globally important, as similar knowledge gaps about marine environmental issues have been identified in the United States and the United Kingdom. © 2014 Elsevier Ltd.
National Research Council Canada and Dalhousie University | Date: 2011-05-26
Pharmaceutical and nutraceutical compositions and methods for treating cardiovascular disease, comprising apple skin extracts which can reduce cholesterol levels and inhibit low density lipoprotein (LDL) oxidation in a subject, are provided.
News Article | August 24, 2016
When it comes to drinking water, where there’s lead, there’s usually iron. Researchers have established a correlation between the two metal contaminants but lack a clear understanding of how iron influences the release of toxic lead from pipes into water. And that relationship may be more complex than water experts anticipated, according to Graham Gagnon, director of the Center for Water Resources Studies at Dalhousie University. Iron mineral nanoparticles may play a hitherto unconsidered role in helping lead leach into tap water, Gagnon said Wednesday morning at the American Chemical Society national meeting in Philadelphia. Researchers who study drinking water currently consider metals in two forms: dissolved or particulate, which means metallic bits larger than about 450 nm, Gagnon explained in a session sponsored by the Division of Colloid & Surface Chemistry. Colloidal nanoparticles don’t fit squarely into either category. Yet these particles, which are roughly 10 nm in diameter, accounted for more than 30% of the lead content in simulated drinking water samples analyzed by Gagnon and his colleague, Benjamin F. Trueman. The team analyzed water from a model pipeline system representing a common construction in North America, where cast iron main pipelines carry water over long distances. Shorter lead distribution lines then connect the main to residences and businesses. Although the model system fit on a benchtop, the duo built and operated it using authentic materials and practices. The researchers collected water that spent months in their system and used a combination of size exclusion chromatography and inductively-coupled mass spectrometry to reveal nanoscopic iron minerals, including goethite and magnetite (Environ. Sci. Technol. 2016, DOI: 10.1021/acs.est.6b01153). It remains unclear exactly how the iron particles and lead pipes interact, but Gagnon posited that the nanoparticles release lead electrochemically and absorb it. Now that researchers know the nanoparticles are in water, they can start asking more specific questions about them, said Irina Chernyshova, a physical chemist in the environmental engineering department at Columbia University. For instance, scientists can now examine iron particle-lead pipe interactions, considering variables such as a water’s pH and salinity, along with nanoparticle size and geometry. For his part, Gagnon is interested in exploring how corrosion inhibitors for pipes, primarily orthophosphate, affect the nanoparticles. That understanding could help better protect people as long as lead pipes remain in water systems, he said. All or nothing is a better strategy for keeping drinking water lead levels low
News Article | June 2, 2016
Sulfur dioxide (SO2), which is a recognized health threat, plays a contributing role in the development of acid rain. SO2 is also one of the six pollutants that the U.S. Environmental Protection Agency (EPA) regulates. A new satellite-based method allowed a team of scientists across various affiliations to locate new sources of man-made SO2 emissions. Lead author and atmospheric scientist Chris McLinden said that satellite images of sulfur dioxide activities appear as "hotspots." McLinden, who is from the Climate Change Canada in Toronto, added that these make estimating emissions easier. The findings provided new independent SO2 emission sources that do not rely on current monitoring techniques. At present, monitoring SO2 activities include analysis of emission records. These data are taken from ground measurements as well as other factors including fuel usage. However, in order to create a complete and precise SO2 emissions records, governments and industries must first determine their exact locations. Teams from the University of Maryland and NASA in the United States and Dalhousie University and the Climate Change in Canada analyzed satellite data taken from 2005 to 2014. The satellite's spatial coverage coupled with new data analysis methods allowed the teams to zone in even on the smaller sources of pollutants. Among the 39 unreported SO2 emissions they found included groups of power plants using coal as well as gas and oil operations. The areas included Mexico, Middle East and several areas in Russia. Some of the reported SO2 emission activities in these regions were actually two to three times lesser than the estimates taken by satellite. But the total amount of underreported and unreported SO2 sources make up 12 percent of all man-made SO2 emissions. "Quantifying the sulfur dioxide bull's-eyes is a two-step process that would not have been possible without two innovations in working with the satellite data," said study co-author and atmospheric scientist Nickolay Krotkov from NASA's Goddard Space Flight Center. The new research was published in the journal Nature Geoscience on May 30. © 2016 Tech Times, All rights reserved. Do not reproduce without permission.
News Article | August 22, 2016
« ABI Research: highly automated driving to spark adoption of centralized advanced driver assistance systems | Main | IACMI, DuPont and Purdue partner on automotive carbon-fiber composites » Conventional electrolytes for Li-ion batteries contain ethylene carbonate (EC) and other additives. However, the cycling performance of Li-ion cells using these carbonate-based electrolytes has been poor at higher voltages (≥4.4 V) due to increased electrolyte oxidation at the surface of the cathode as the potential increases. This increased oxidation results in salt consumption, gas evolution and impedance growth, all reducing the energy density and the lifetime of Li-ion cells. A team led by Professor Jeff Dahn at Dalhousie University (Canada) has now demonstrated that EC is actually detrimental for Li-ion cells at high voltages and that cyclic carbonates such as VC (vinylene carbonate), FEC (fluoroethylene carbonate) and DiFEC ((4R,5S)-4,5-Difluoro-1,3-dioxolan-2-one) can act as the enablers for EMC (ethylmethyl carbonate)-based electrolytes which function well in NMC442/graphite cells tested up to 4.4 or 4.5 V. A paper on their work is published the Journal of Power Sources. The team has also submitted a related paper to the Journal of the Electrochemical Society. (Dahn and his team recently began an exclusive five-year research partnership with Tesla, earlier post.) EC has been considered essential for the passivation of the graphite electrodes surface during the first cycle. However, left-over EC in the electrolyte may be continuously oxidized at the positive electrode in cells operated to high voltage. This may lead to gas generation and impedance growth. Dahn and his team recently showed (as reported in the paper submitted to JES) that the removal of EC from carbonate-based electrolytes yielded high voltage Li-ion cells with longer life-time. The Dahn team has also shown that EC-free-linear alkyl carbonate-based electrolytes with a small amount of “enabler”—vinylene carbonate (VC)—allowed NMC(442)/graphite cells to be cycled up to 4.4 V with longer cycle and calendar life, compared to cells with a state-of-the-art electrolyte incorporating additives. As an example, NMC(442)/graphite cells filled with 1 M LiPF EMC:VC (98:2) + 2% PPF (pyridine phosphorus pentafluoride) had longer cycle life at both room temperature and 55 ˚ C when cycled up to 4.4 V than cells with EC-based electrolytes incorporating state of the art additive blends. The EMC:VC (98:2) electrolyte system also has acceptable conductivity, wets separators quickly, shows good tolerance to high voltage and provides cells with low polarization growth when cycled up to 4.4 V. In this paper, four “enablers” including EC, VC, FEC and DiFEC were compared head to head in NMC442/graphite pouch type Li-ion cells. Other enablers such as SA, MEC, PES will not be included in this paper but will be discussed in latter publications. Experiments were made using ultra high precision coulometry (UHPC), a precision storage system, electrochemical impedance spectroscopy (EIS) and a gas measurement. Gas evolution during formation and cycling, coulombic efficiency, charge endpoint capacity slippage during cycling and EIS spectra before and after cycling were examined and were compared to EC-based electrolyte with some promising additive blends. The combination of EMC with appropriate amounts of these enablers yielded cells with better performance than cells with EC-containing electrolytes incorporating additives tested to 4.5 V. The work in this paper suggests that EC itself is the root cause of many issues associated with the operation of NMC/graphite cells to high potential. Electrolyte oxidation reactions at high voltages cause gas evolution and impedance growth, leading to cell failure. These parasitic reactions become very problematic at 4.5 V even with state of the art electrolyte additives PES211 in EC:EMC electrolyte. … This work demonstrates that cyclic carbonates such as VC, FEC and DiFEC can act as the enablers for EMC-based electrolytes which function well in NMC442/graphite cells tested up to 4.4 or 4.5 V. … Further work should be done to optimize the amount of these and other enablers and to find other co-additives that can be used together with these enablers to improve cell performance. It is very likely that other enablers can also function well. It is also very likely other linear carbonates besides EMC can function well in electrolytes without EC. Further work may also include the exploration of cycling performance at high temperature, low temperature, high rate as well as the performance in different cell chemistries (ie. LiCoO (LCO)/graphite and LiNi Co Al O (NCA)/graphite Li-ion cells). It is essential that other researchers get involved in such searches. The work was supported financially by NSERC and 3M Canada under the auspices of the Industrial Research Chairs program. (3M and NSERC had funded Dahn’s Industrial Research Chair in Materials for Advanced Batteries since 1996. This supported ended in June 2016, and the Tesla relationship took over.)
News Article | December 14, 2016
In crested penguin families, moms heavily favor offspring No. 2 from the start, and a new analysis proposes why. The six or seven species of crested (Eudyptes) penguins practice the most extreme egg favoritism known among birds, says Glenn Crossin of Dalhousie University in Halifax, Canada. Females that lay two eggs produce a runty first egg weighing 18 to 57 percent less than the second, with some of the greatest mismatches among erect-crested and macaroni penguins. Some Eudyptes species don’t even incubate the first egg; royal penguins occasionally push it out of the nest entirely. Biologists have proposed benefits for the unusual behavior: A sacrificial first egg might mark a claim to a nesting spot or improve chances of one chick surviving predators. But those ideas haven’t held up, Crossin says. He and Tony Williams of Simon Fraser University in Burnaby, Canada, propose in the Oct. 12 Proceedings of the Royal Society B that egg favoritism is just a downside of an open-water, migratory lifestyle. Among the 16 penguin species that lay two eggs, only the Eudyptes species evolved what’s called a pelagic life, spending their nonbreeding season mostly at sea and migrating, in some cases considerable distances, to breeding sites. Female crested penguins tend to lay their first eggs soon after arriving at a breeding site, meaning that the egg must have started its roughly 16-day development while mom was migrating. The biology of long swims, now encoded genetically, interferes with producing a full-sized egg. A puny first egg might just be a sign that mom is trying to do two things at once, Crossin says.
News Article | August 24, 2016
Jeff Dahn’s battery technology research team at Dalhousie University in Canada has developed a new means of improving high-voltage, lithium-ion battery cell performance through the use of cyclic carbonates as the enablers for ethylmethyl carbonate (EMC)-based electrolytes, rather than conventional options, according to recent reports. The research showed that the cyclic carbonates in question — VC (vinylene carbonate), FEC (fluoroethylene carbonate), and DiFEC ((4R,5S)-4,5-Difluoro-1,3-dioxolan-2-one) — reportedly worked well as the enablers for the aforementioned EMC-based electrolytes when used in NMC442/graphite battery cells tested at high voltages (up to 4.4 V or 4.5 V). The work clarified that the conventionally used ethylene carbonate (EC) electrolyte additive is detrimental to lithium-ion battery cell health (cycle and calendar life) at high voltages. EC use (for passivation of graphite electrodes during initial cycles) is now known to be associated with oxidation, gas generation, and impedance growth — meaning that removal has been shown to increase the working life of high-voltage lithium-ion cells. Here’s an explanation of the work directly from the paper: “In this paper, four ‘enablers’ including EC, VC, FEC and DiFEC were compared head to head in NMC442/graphite pouch type Li-ion cells. Other enablers such as SA, MEC, PES will not be included in this paper but will be discussed in latter publications. Experiments were made using ultra high precision coulometry (UHPC), a precision storage system, electrochemical impedance spectroscopy (EIS) and a gas measurement. Gas evolution during formation and cycling, coulombic efficiency, charge endpoint capacity slippage during cycling, and EIS spectra before and after cycling, were examined and were compared to EC-based electrolyte with some promising additive blends.” As an example, the combo of EMC with specific amounts of some of the enablers mentioned above resulted in battery cells with improved performance as compared to battery cells with EC-containing electrolytes with additives, when tested up to 4.5 V. The paper provides more: “The work in this paper suggests that EC itself is the root cause of many issues associated with the operation of NMC/graphite cells to high potential. Electrolyte oxidation reactions at high voltages cause gas evolution and impedance growth, leading to cell failure. These parasitic reactions become very problematic at 4.5 V even with state of the art electrolyte additives PES211 in EC:EMC electrolyte. … This work demonstrates that cyclic carbonates such as VC, FEC, and DiFEC can act as the enablers for EMC-based electrolytes which function well in NMC442/graphite cells tested up to 4.4 or 4.5 V.” The paper notes that more work needs to be done in order to “optimize the amount of these and other enablers and to find other co-additives that can be used together with these enablers to improve cell performance. It is very likely that other enablers can also function well. It is also very likely other linear carbonates besides EMC can function well in electrolytes without EC. Further work may also include the exploration of cycling performance at high temperature, low temperature, high rate as well as the performance in different cell chemistries (ie. LiCoO2 (LCO)/graphite and LiNi0.80Co0.15Al0.05O2 (NCA)/graphite Li-ion cells). It is essential that other researchers get involved in such searches.” A couple of final things that should be noted with regard to this work: A patent has been filed for the work by 3M; financial support was provided by NSERC and 3M Canada through the Industrial Research Chairs program; and, while Dahn is now in an exclusive 5-year research partnership with Tesla that began in June, most or all of this work predates that agreement. The new work is detailed in a paper published in the Journal of Power Sources, and another paper has been submitted by the researchers to the Journal of the Electrochemical Society. Drive an electric car? Complete one of our short surveys for our next electric car report. Keep up to date with all the hottest cleantech news by subscribing to our (free) cleantech newsletter, or keep an eye on sector-specific news by getting our (also free) solar energy newsletter, electric vehicle newsletter, or wind energy newsletter.
News Article | August 24, 2016
When it comes to drinking water, where there’s lead, there’s usually iron. Researchers have established a correlation between the two metal contaminants but lack a clear understanding of how iron influences the release of toxic lead from pipes into water. And that relationship may be more complex than water experts anticipated, according to Graham Gagnon, director of the Center for Water Resources Studies at Dalhousie University. Iron mineral nanoparticles may play a hitherto unconsidered role in helping lead leach into tap water, Gagnon said Wednesday morning at the American Chemical Society national meeting in Philadelphia. Researchers who study drinking water currently consider metals in two forms: dissolved or particulate, which means metallic bits larger than about 450 nm, Gagnon explained in a session sponsored by the Division of Colloid & Surface Chemistry. Colloidal nanoparticles don’t fit squarely into either category. Yet these particles, which are roughly 10 nm in diameter, accounted for more than 30% of the lead content in simulated drinking water samples analyzed by Gagnon and his colleague, Benjamin F. Trueman. The team analyzed water from a model pipeline system representing a common construction in North America, where cast iron main pipelines carry water over long distances. Shorter lead distribution lines then connect the main to residences and businesses. Although the model system fit on a benchtop, the duo built and operated it using authentic materials and practices. The researchers collected water that spent months in their system and used a combination of size exclusion chromatography and inductively-coupled mass spectrometry to reveal nanoscopic iron minerals, including goethite and magnetite (Environ. Sci. Technol. 2016, DOI: 10.1021/acs.est.6b01153). It remains unclear exactly how the iron particles and lead pipes interact, but Gagnon posited that the nanoparticles release lead electrochemically and absorb it. Now that researchers know the nanoparticles are in water, they can start asking more specific questions about them, said Irina Chernyshova, a physical chemist in the environmental engineering department at Columbia University. For instance, scientists can now examine iron particle-lead pipe interactions, considering variables such as a water’s pH and salinity, along with nanoparticle size and geometry. For his part, Gagnon is interested in exploring how corrosion inhibitors for pipes, primarily orthophosphate, affect the nanoparticles. That understanding could help better protect people as long as lead pipes remain in water systems, he said. All or nothing is a better strategy for keeping drinking water lead levels low
Parker R.W.R.,University of Tasmania |
Tyedmers P.H.,Dalhousie University
Fish and Fisheries | Year: 2014
Compared to a century ago, the world's fishing fleets are larger and more powerful, are travelling further and are producing higher quality products. These developments come largely at a cost of high-fossil fuel energy inputs. Rising energy prices, climate change and consumer demand for 'green' products have placed energy use and emissions among the sustainability criteria of food production systems. We have compiled all available published and unpublished fuel use data for fisheries targeting all species, employing all gears and fishing in all regions of the world into a Fisheries and Energy Use Database (FEUD). Here, we present results of our analysis of the relative energy performance of fisheries since 1990 and provide an overview of the current state of knowledge on fuel inputs to diverse fishing fleets. The median fuel use intensity of global fishery records since 1990 is 639 litres per tonne. Fuel inputs to fisheries vary by several orders of magnitude, with small pelagic fisheries ranking among the world's most efficient forms of animal protein production and crustaceans ranking among the least efficient. Trends in Europe and Australia since the beginning of the 21st century suggest fuel use efficiency is improving, although this has been countered by a more rapid increase in oil prices. Management decisions, technological improvements and behavioural changes can further reduce fuel consumption in the short term, although the most effective improvement to fisheries energy performance will come as a result of rebuilding stocks where they are depressed and reducing over-capacity. © 2014 John Wiley & Sons Ltd.
Jackman J.E.,Ohio State University |
Gott J.M.,Case Western Reserve University |
Gray M.W.,Dalhousie University
RNA | Year: 2012
The tRNA His guanylyltransferase (Thg1) family of enzymes comprises members from all three domains of life (Eucarya, Bacteria, Archaea). Although the initial activity associated with Thg1 enzymes was a single 3′-to-5′ nucleotide addition reaction that specifies tRNA His identity in eukaryotes, the discovery of a generalized base pair-dependent 3′-to-5′ polymerase reaction greatly expanded the scope of Thg1 family-catalyzed reactions to include tRNA repair and editing activities in bacteria, archaea, and organelles. While the identification of the 3′-to-5′ polymerase activity associated with Thg1 enzymes is relatively recent, the roots of this discovery and its likely physiological relevance were described ∼30 yr ago. Here we review recent advances toward understanding diverse Thg1 family enzyme functions and mechanisms. We also discuss possible evolutionary origins of Thg1 family-catalyzed 3′-to-5′ addition activities and their implications for the currently observed phylogenetic distribution of Thg1-related enzymes in biology. Published by Cold Spring Harbor Laboratory Press. Copyright © 2012 RNA Society.
Gillis L.D.,Atlantic Cancer Research Institute |
Lewis S.M.,Atlantic Cancer Research Institute |
Lewis S.M.,Dalhousie University |
Lewis S.M.,University of New Brunswick
Oncogene | Year: 2013
eIF3e/Int6 is a component of the multi-subunit eIF3 complex, which binds directly to the 40S ribosome to facilitate ribosome recruitment to mRNA and hence protein synthesis. Reduced expression of eIF3e/Int6 has been found in up to 37% of human breast cancers, and expression of a truncated mutant version of the mouse eIF3e/Int6 protein leads to malignant transformation of normal mammary cells. These findings suggest that eIF3e/Int6 is a tumor suppressor; however, a recent study has reported that a reduction of eIF3e/Int6 expression in breast cancer cells leads to reduced translation of oncogenes, suggesting that eIF3e/Int6 may in fact have an oncogenic role in breast cancer. To gain a better understanding of the role of eIF3e/Int6 in breast cancer, we have examined the effects of decreased eIF3e/Int6 expression in an immortalized breast epithelial cell line, MCF-10A. Surprisingly, we find that decreased expression of eIF3e/Int6 causes breast epithelial cells to undergo epithelial-to-mesenchymal transition (EMT). We show that EMT induced by a decrease in eIF3e/Int6 expression imparts invasive and migratory properties to breast epithelial cells, suggesting that regulation of EMT by eIF3e/Int6 may have an important role in breast cancer metastasis. Furthermore, we show that reduced eIF3e/Int6 expression in breast epithelial cells causes a specific increase in the expression of the key EMT regulators Snail1 and Zeb2, which occurs at both the transcriptional and post-transcriptional levels. Together, our data indicate a novel role of eIF3e/Int6 in the regulation of EMT in breast epithelial cells and support a tumor suppressor role of eIF3e/Int6. © 2013 Macmillan Publishers Limited.
Hartmann K.,University of Tasmania |
Wong D.,Dalhousie University |
Stadler T.,Universitatsstrasse 16
Systematic Biology | Year: 2010
A wide range of evolutionary models for species-level (and higher) diversification have been developed. These models can be used to test evolutionary hypotheses and provide comparisons with phylogenetic trees constructed from real data. To carry out these tests and comparisons, it is often necessary to sample, or simulate, trees from the evolutionary models. Sampling trees from these models is more complicated than it may appear at first glance, necessitating careful consideration and mathematical rigor. Seemingly straightforward sampling methods may produce trees that have systematically biased shapes or branch lengths. This is particularly problematic as there is no simple method for determining whether the sampled trees are appropriate. In this paper, we show why a commonly used simple sampling approach (SSA)-simulating trees forward in time until n species are first reached-should only be applied to the simplest pure birth model, the Yule model. We provide an alternative general sampling approach (GSA) that can be applied to most other models. Furthermore, we introduce the constant-rate birth-death model sampling approach, which samples trees very efficiently from a widely used class of models. We explore the bias produced by SSA and identify situations in which this bias is particularly pronounced. We show that using SSA can lead to erroneous conclusions: When using the inappropriate SSA, the variance of a gradually evolving trait does not correlate with the age of the tree; when the correct GSA is used, the trait variance correlates with tree age. The algorithms presented here are available in the Perl Bio:Phylo package, as a stand-alone program TreeSample, and in the R TreeSim package. © The Author(s) 2010.
Langley R.G.,Dalhousie University |
Dauden E.,Hospital Universitario Of La Princesa
Dermatology | Year: 2010
Nail involvement in psoriasis is typically overlooked, although it can affect up to 50% of patients with psoriasis and cause functional impact as well as psychological stress that can significantly affect quality of life. In addition, psoriatic patients with nail disease tend to have a more severe skin condition, a higher rate of unremitting and progressive arthritis and more associated anxiety and depression. Historically, the treatment of nail psoriasis has proven difficult, with most patients feeling that the treatment for their nail disease was unsatisfactory. The current management of nail psoriasis includes topical, intralesional and systemic therapies, although little clinical evidence is available on the effectiveness of conventional treatments and, consequently, no specific treatment approach has been fully supported. Biologic agents are beginning to emerge as a viable option to treat patients with both cutaneous and nail clinical manifestations of psoriasis and psoriatic arthritis. The extra disease burden that nail symptoms place on the patient can be considered indicative of a more severe form of the disease and should be taken into consideration when assessing treatment options. © 2010 S. Karger AG, Basel.
Tam N.,University of Cape Town |
Wilson J.L.A.,Dalhousie University |
Noakes T.D.,University of Cape Town |
Tucker R.,University of Cape Town
British Journal of Sports Medicine | Year: 2014
Barefoot running has become a popular research topic, driven by the increasing prescription of barefoot running as a means of reducing injury risk. Proponents of barefoot running cite evolutionary theories that longdistance running ability was crucial for human survival, and proof of the benefits of natural running. Subsequently, runners have been advised to run barefoot as a treatment mode for injuries, strength and conditioning. The body of literature examining the mechanical, structural, clinical and performance implications of barefoot running is still in its infancy. Recent research has found significant differences associated with barefoot running relative to shod running, and these differences have been associated with factors that are thought to contribute to injury and performance. Crucially, long-term prospective studies have yet to be conducted and the link between barefoot running and injury or performance remains tenuous and speculative. The injury prevention potential of barefoot running is further complicated by the complexity of injury aetiology, with no single factor having been identified as causative for the most common running injuries. The aim of the present review was to critically evaluate the theory and evidence for barefoot running, drawing on both collected evidence as well as literature that have been used to argue in favour of barefoot running. We describe the factors driving the prescription of barefoot running, examine which of these factors may have merit, what the collected evidence suggests about the suitability of barefoot running for its purported uses and describe the necessary future research to confirm or refute the barefoot running hypotheses.
Morsi W.G.,University of New Brunswick |
El-Hawary M.E.,Dalhousie University
Electric Power Systems Research | Year: 2010
High power quality (PQ) level represents one of the main objectives towards smart grid. The currently used PQIs that are a measure of the PQ level are defined under the umbrella of the Fourier foundation that produces unrealistic results in case of non-stationary PQ disturbances. In order to accurately measure those indices, wavelet packet transform (WPT) is used in this paper to reformulate the recommended PQIs and hence benefiting from the WPT capabilities in accurately analyzing non-stationary waveforms and providing a uniform time-frequency sub-bands leading to reduced size of the data to be processed which is a necessity to facilitate the implementation of smart grid. Numerical examples' results considering non-stationary waveforms prove the suitability of the WPT for PQIs measurement; also the results indicate that Daubechies 10 could be the best candidate wavelet basis function that could provide acceptable accuracy while requiring less number of wavelet coefficients and hence reducing the data size. Moreover, a new time-frequency overall and node crest factors are introduced in this paper. The new node crest factor is able to determine the node or the sub-band that is responsible for the largest impact which could not be achieved using traditional approaches. © 2009 Elsevier B.V. All rights reserved.
Dinning K.M.,University of New Brunswick |
Metaxas A.,Dalhousie University
Marine Ecology | Year: 2013
This study describes changes in abundance of hyperbenthic zooplankton (including meroplankton) and benthic colonists at the seasonally hypoxic seabed of Saanich Inlet, British Columbia, Canada. We used the Victoria Experimental Network Under the Sea (VENUS) cabled observatory to measure water properties and to sample hyperbenthos with a sediment trap at 97m from September 2008 to September 2009. Some faunal groups exhibited seasonal reproduction, and abundance peaked during their reproductive periods. These included larvae of the barnacle Balanus crenatus, and the crabs Petrolisthes eriomerus, Oregonia gracilis, and Lophopanopeus bellus bellus. Other groups were most abundant in spring and summer when food and oxygen levels were highest and temperature was lowest. These included cumaceans, the siphonophore Diphyes sp., the bryozoan Triticella pedicellata, and tintinnids. We also collected benthic colonists, predominantly bryozoans and polychaetes, on colonization plates deployed in spring/summer 2008, fall 2008/winter 2009, and spring/summer 2009. The total abundance of colonists and of bryozoans did not vary seasonally or with substrate complexity, whereas polychaetes were more numerous in spring/summer deployments and on a highly complex substrate. Taxon richness of colonists was higher in spring/summer 2008 than in fall 2008/winter 2009, whereas an anoxic episode in spring/summer 2009 reduced richness to similar values with that of fall 2008/winter 2009 levels. Substrate complexity had no effect on richness. Juvenile squat lobsters, digitally imaged in fall 2008/winter 2009, were most numerous when oxygen levels were lowest and potentially excluding larger predators. Our study illustrates how season, food availability, temperature, and oxygen can interact to shape community structure in a seasonally hypoxic habitat. © 2012 Blackwell Verlag GmbH.
Parker R.W.R.,University of Tasmania |
Tyedmers P.H.,Dalhousie University
Fish and Fisheries | Year: 2015
Compared to a century ago, the world's fishing fleets are larger and more powerful, are travelling further and are producing higher quality products. These developments come largely at a cost of high-fossil fuel energy inputs. Rising energy prices, climate change and consumer demand for 'green' products have placed energy use and emissions among the sustainability criteria of food production systems. We have compiled all available published and unpublished fuel use data for fisheries targeting all species, employing all gears and fishing in all regions of the world into a Fisheries and Energy Use Database (FEUD). Here, we present results of our analysis of the relative energy performance of fisheries since 1990 and provide an overview of the current state of knowledge on fuel inputs to diverse fishing fleets. The median fuel use intensity of global fishery records since 1990 is 639 litres per tonne. Fuel inputs to fisheries vary by several orders of magnitude, with small pelagic fisheries ranking among the world's most efficient forms of animal protein production and crustaceans ranking among the least efficient. Trends in Europe and Australia since the beginning of the 21st century suggest fuel use efficiency is improving, although this has been countered by a more rapid increase in oil prices. Management decisions, technological improvements and behavioural changes can further reduce fuel consumption in the short term, although the most effective improvement to fisheries energy performance will come as a result of rebuilding stocks where they are depressed and reducing over-capacity. © 2015 John Wiley & Sons Ltd.
News Article | February 27, 2017
It is 2012 and Smiley, a young woman in her early 20s, lives in a single room occupancy (SRO) building in Vancouver. She wants to hang out with her friends in her room, where she feels safe, but the SRO only allows one visitor at a time. "I don't like it. It's their rules. It's really annoying," Smiley said. "It sucks, because I'm not a crackhead or a junkie. They shouldn't put me in places like that." Smiley has been diagnosed with psychosis, a mental disorder where people show signs of delusions and hallucinations. She's one of 17 young people between the ages of 18 to 24 in Metro Vancouver recruited for a study at the University of British Columbia. All participants have experienced symptoms of psychosis in the past three years. "Our study provides a window into what young people think about the mental health services they receive and what they feel helps and hinders their well-being," said lead author Shalini Lal, an assistant professor at the University of Montreal's school of rehabilitation and a researcher at the University of Montreal's Hospital Research Centre (CRCHUM). Lal conducted the study as part of her PhD work at UBC's faculty of medicine within the graduate programs of rehabilitation sciences. Through interview excerpts with the youth from November 2010 to March 2012, the study highlights the impacts of mental health services on these young people, including their interactions with psychiatrists, case managers, social workers and supports for housing, recreation, and employment. "Eliciting young people's feedback will lead to better planning and coordination of services that they will find engaging, meaningful and effective," said Lal. The study identifies many different types of supports the youth found helpful, including group therapy and positive interactions with peers and peer support workers. "The groups were very helpful for getting me to acknowledge that I actually had an illness," said Kevin, one of the youth. "(The peer support worker) explained that with the right combination of medications or professional help, you could actually treat the symptoms and live a normal life... a good role model to see that you could recover from it," said Jake, another youth involved in the study. Other types of support the youth identified as helpful were accompaniment to appointments, providing help in completing employment assistance forms and facilitating the process of returning to school. Youth also appreciated emotional support like signs of genuine kindness, hope and encouragement from service providers. "Even small gestures were seen as helpful, ones we may take for granted, like a care manager shaking their hand when they walked in the door," said Lal. "That gesture of respect has a lot of meaning for someone stigmatized by mental illness." When it came to hindrances, some youth felt pigeonholed by their mental illness, being offered services that didn't reflect an identity outside their disorder. A young man named Nelson, who had acting aspirations, told Lal about his disappointment when his job counselor connected him to a theatre company dedicated to "people affected by mental illness." "The most annoying thing is that everything is for mental health reasons and I just don't want this," he said. "If it's a film thing, I don't want it to be just for mentally ill, and just to address stuff like that. I want it to be, just normal." Darren, a 20-year-old living in a downtown youth shelter, didn't own a cellphone and could not receive calls directly from the shelter. His sense of independence and social life were negatively impacted by the shelter's rules of no Facebook access, which was his main way of staying in touch with friends and family. Lal said in some cases the youth also interacted with outreach workers online, which proved useful to providing support to people who would not otherwise receive it any other way. Some youth felt "ghettoized" by their housing situation, only being able to access SROs that housed many others living with mental health and substance abuse issues. Philip, a young man struggling with substance abuse in addition to his psychosis, said living in such an environment threatened his sobriety. "Every time you walk down the street you see someone on a crack pipe, a crystal meth pipe, a pot pipe or drinking alcohol every block you walk here," he said. "And it's nothing but trigger after trigger here, so it's not the right environment for people trying to stay sober. Just being around these kinds of people, it's not the right place for me." The last hindrance was how impersonal the youth felt some of their encounters could be with different support workers, including doctors or therapists. "It was always kind of detached, and I always felt like we were on the clock and not really supported to talk about things like that [relationships]... It just wasn't an environment where I felt comfortable with it," said Kevin. Lal said she has seen more funding and attention being paid to the mental health needs of young people in Canada, especially over the past five years. Lal also said more effort is needed in using tools and resources that cater to youth, including the use of technology to provide support. As well, different sectors of the community, including housing, employment and mental health, need to work more closely together, so people don't feel bounced around. "People often think that it's up to individuals alone to overcome adversity, to deal with a mental illness," Lal said. "For young people, their resiliency largely depends on their ability to navigate and negotiate towards resources, which are all too often substandard, inconsistent or not tailored to their needs." "We learned from this study that when services do match young people's needs and preferences, they can really make a positive impact on their well-being." The study, Impact of Mental Health Services on Resilience in Youth with First Episode Psychosis: A Qualitative Study, was published in print this year in Administration and Policy in Mental Health and Mental Health Services Research. Lal's co-authors are Michael Ungar at Dalhousie University, Ashok Malla at McGill University and Carl Leggo and Melinda Suto at UBC. The 17 youth involved in the study had an average age of 22 and 71 per cent were male. The youth were white, First Nations, Asian and Latin American. Seven of the youth had less than a high school education, five had completed high school, four had some university-level education, and one had completed a bachelor's degree. Names in this study were changed to protect the youths' identities and were chosen by the youth themselves. They are not available for interviews.
News Article | November 19, 2016
A team at Dalhousie University in Halifax is leading a study on the connections between migratory Arctic seabirds, cloud formation and the Arctic climate. They have found that the ammonia from Arctic seabird droppings is linked to the development of atmospheric aerosol particles, and that those particles spread throughout the Arctic, help cloud formation and create a cooling effect when they reflect more solar energy back into space.
News Article | December 3, 2015
This story has been updated. Freshwater is one of the planet’s most precious resources — and as the global population grows and our demand for water rises, so does the need to carefully monitor its use and availability. Numerous studies have attempted to calculate the amount of freshwater humans consume globally from year to year. But in a worrying new study in the journal Science, scientists argue that we’ve been significantly underestimating our water footprint — in fact, their research raises the estimate of our global water consumption by nearly 20 percent and suggests that we may have crossed an unsustainable threshold in our water use. Authors Fernando Jaramillo and Georgia Destouni of Stockholm University focused their research on the effects of flow regulation and irrigation — essentially, building dams and reservoirs for human use — on the water cycle, and found that previous studies have significantly underestimated their influence. Notably, they found a significant increase in water consumption — thousands of cubic kilometers worth — in the latter half of the twentieth century due to human water management. These practices can have an important influence on what scientists call “evapotranspiration,” which is water that is lost to the atmosphere by either evaporating from the Earth’s surface or being taken up by plants and later released into the air through their leaves. Such factors can add up to a very significant percentage of global water consumption. While most people think about “water consumption” as referring to the amount of water humans drink or use for industry, water that evaporates into the atmosphere is actually a major component too, said Jaramillo. This handy blog from the World Resources Institute helps explain the concept: Essentially, water consumption refers to any water that is withdrawn and not immediately returned to its original source. So when water vaporizes and goes into the atmosphere as a result of human actions, such as irrigation or dam-building, it counts as being consumed by humans — even if it comes back down to the Earth at a later point as rain. It’s important to think about consumption in this way: Water that goes into the atmosphere in one place doesn’t necessarily come back down in the same location or in the same amount . And by engaging in practices that cause more water to be lost into the atmosphere than naturally would, humans are interfering with the natural ratio of evapotranspiration to precipitation — in other words, water out versus water in — and that could lead to increases in water shortages down the road. “A scientific motivation for this [study] is that we want to understand what is it that drives changes in the freshwater system on land,” said Destouni, the senior author and a professor of hydrology and water resources at Stockholm University. And as the research was conducted, she said, “we started to see that the landscape drivers of change [including human water management] were actually important nearly everywhere.” There are a variety of ways that human water management techniques can affect how much water is lost to the atmosphere as water vapor, not all of them well understood. Creating reservoirs means there’s a larger surface area of standing water, which can increase evaporation rates. Additionally, irrigation can increase the number of plants in an area, which then draw in more water and release it into the air through their leaves, the process known as transpiration. The authors decided to determine the global impact of flow regulation and irrigation on the water cycle in order to figure out how much water is being consumed, or lost to the atmosphere, just as a result of these practices. They selected 100 large water basins from around the world to use as a sample, choosing basins “that were more representative and had long-term consistent data on climate and water change and long-term data on water use and land use,” Jaramillo said. They then used these data to figure out the ratio of evapotranspiration to precipitation — essentially, water out versus water in — between 1901 and 2008. In the past, studies examining the influence of flow regulation and irrigation on the water footprint have used global-scale models, which the authors argue have underestimated the effects on the water cycle. Their study is the first to take a global look at these practices using observed historical data. “What is really novel and exciting about what Dr. Jaramillo and Destouni did was they took observational data, so measured flow data, on major watersheds, and they were able to detect a signal of a specific human impact,” said Shannon Sterling, an associate professor in the Department of Earth Sciences at Dalhousie University, who was not involved with this paper. “And that’s remarkable.” After conducting their analysis, the researchers found that between the period from 1901 to 1954 and the period from 1955 to 2008, there was an increase in the average loss of freshwater to the atmosphere of more than 3,500 cubic kilometers, or about 850 cubic miles, of water. Altogether, they estimate that the current level of human freshwater consumption is about 4,370 cubic kilometers, or close to 1,050 cubic miles, per year. These calculations raise the estimated total human water footprint — that’s all water consumed, freshwater or otherwise — by a whopping 18 percent, bringing it up to about 10,688 cubic kilometers per year. The authors note that previous papers have proposed a “planetary boundary” of 4,000 cubic kilometers of freshwater consumption per year. Beyond that point, some scientists say that water consumption becomes unsustainable for the Earth’s growing population. Notably, this new study brings the total estimated freshwater consumption above the proposed planetary boundary. “Whether this actually is a real boundary, of course there’s huge uncertainty related to that,” Destouni said, but added that the study’s results are concerning either way. “It’s very serious that with such a relatively straightforward thing as water, freshwater — all of us use it all the time — we don’t keep track of what changes we have made and how these changes actually relate to what the planet can withstand,” she said. Sterling also pointed out that the paper suggests human activities have a particular influence in already water-stressed regions. “Another important implication of what they found [is that] the biggest reductions in available water from these human activities of dam building and irrigation are in areas that are already arid,” she said. “In these areas, they probably built dams and irrigation to address an existing water stress in the first place.” The study highlights a critical need for better monitoring of our freshwater use and the ways our management techniques can affect the water cycle, as Jaramillo noted that the current effects of human water management “are even larger and more recognizable than the effects of atmospheric climate change.” As climate change is predicted to become an increasing threat to water security worldwide, the persistent impacts of human activity on the water cycle will only be compounded by the effects of global warming in the future — making the need for better management techniques an even higher priority. “That’s another future direction our society needs to take — to go towards greater resource efficiency,” Destouni said. “And if we don’t keep track of how we use water, we cannot reach that efficiency, or even understand what that efficiency means for the future.”
News Article | November 17, 2016
Colorado State University atmospheric scientists are working to better understand key components of Arctic climate systems FORT COLLINS, COLORADO - It turns out bird poop helps cool the Arctic. That's according to new research from Colorado State University atmospheric scientists, who are working to better understand key components of Arctic climate systems. Publishing in Nature Communications and featured by the American Association for the Advancement of Science, Associate Professor of Atmospheric Science Jeff Pierce and graduate student Jack Kodros present evidence linking ammonia emissions from summertime Arctic seabird-colony excrement, called guano, to newly formed atmospheric aerosol particles. These particles can in turn influence Arctic cloud properties and their effects on climate. Clouds play a key role in modulating Arctic temperature; thus, understanding factors that influence clouds is essential, Pierce says. Central to the development of clouds is the availability of cloud condensation nuclei - small atmospheric particles around which water can condense. Using a combination of observations and computer modeling, Pierce, Kodros and co-authors at Dalhousie University, University of Toronto, and Environment and Climate Change Canada determined that migratory-seabird colonies have a definitive influence on atmospheric particles and clouds in the pristine summertime Arctic. They report the presence of summertime bursts of atmospheric particles linked to ammonia emissions from seabird-colony guano. These particles can spread throughout the Arctic, fostering cloud-droplet formation, and in turn reflect sunlight back to space for a net cooling effect. "This newly identified and fascinating ecological-atmospheric connection highlights the interconnectedness of the many components of Earth's climate system," Pierce said.
News Article | November 21, 2016
That's according to new research from Colorado State University atmospheric scientists, who are working to better understand key components of Arctic climate systems. Publishing in Nature Communications and featured by the American Association for the Advancement of Science, Associate Professor of Atmospheric Science Jeff Pierce and graduate student Jack Kodros present evidence linking ammonia emissions from summertime Arctic seabird-colony excrement, called guano, to newly formed atmospheric aerosol particles. These particles can in turn influence Arctic cloud properties and their effects on climate. Clouds play a key role in modulating Arctic temperature; thus, understanding factors that influence clouds is essential, Pierce says. Central to the development of clouds is the availability of cloud condensation nuclei -- small atmospheric particles around which water can condense. Using a combination of observations and computer modeling, Pierce, Kodros and co-authors at Dalhousie University, University of Toronto, and Environment and Climate Change Canada determined that migratory-seabird colonies have a definitive influence on atmospheric particles and clouds in the pristine summertime Arctic. They report the presence of summertime bursts of atmospheric particles linked to ammonia emissions from seabird-colony guano. These particles can spread throughout the Arctic, fostering cloud-droplet formation, and in turn reflect sunlight back to space for a net cooling effect. "This newly identified and fascinating ecological-atmospheric connection highlights the interconnectedness of the many components of Earth's climate system," Pierce said.
News Article | October 28, 2016
The International Association of HealthCare Professionals is pleased to welcome Karen Desrosiers, MD, FRCSC, SOGC, OB/GYN Physician, to their prestigious organization with her upcoming publication in The Leading Physicians of the World. She is a highly trained and qualified obstetrician and gynecologist with an extensive expertise in all facets of her work. Dr. Desrosiers has been in practice for over 11 years and is currently serving patients at the Moncton Hospital of Horizon Health Network in Moncton, New Brunswick, Canada. Additionally, Dr. Desrosiers acts as an Associate Professor with Dalhousie University Faculty of Medicine and Memorial University of Newfoundland Faculty of Medicine. Dr. Desrosiers obtained her Medical Degree in 1997 from L’Université de Sherbrooke – La Faculté de Médecine et des Sciences de la Santé in Sherbrooke, followed by her internship at L’Université de Sherbrooke. Dr. Desrosiers maintains professional memberships with the Society of Obstetricians and Gynaecologists of Canada, the New Brunswick Medical Society, and the American Congress of Obstetricians and Gynecologists. Furthermore, She has earned the coveted title of Fellow of the Royal College of Physicians and Surgeons of Canada. Dr. Desrosiers attributes her success to her hard work, and dedicates her free time to reading and playing the piano. Learn more about Dr. Desrosiers here by reading her upcoming publication in The Leading Physicians of the World. FindaTopDoc.com is a hub for all things medicine, featuring detailed descriptions of medical professionals across all areas of expertise, and information on thousands of healthcare topics. Each month, millions of patients use FindaTopDoc to find a doctor nearby and instantly book an appointment online or create a review. FindaTopDoc.com features each doctor’s full professional biography highlighting their achievements, experience, patient reviews and areas of expertise. A leading provider of valuable health information that helps empower patient and doctor alike, FindaTopDoc enables readers to live a happier and healthier life. For more information about FindaTopDoc, visit:http://www.findatopdoc.com
Russell E.J.,Lakehead University |
Fawcett J.M.,Dalhousie University |
Fawcett J.M.,MRC Cognition and Brain science Unit |
Mazmanian D.,Lakehead University
Journal of Clinical Psychiatry | Year: 2013
Objective: Although pregnant and postpartum women are presumed to be at greater risk of obsessive-compulsive disorder (OCD) than the general population, the evidence has been inconclusive. This meta-analysis provides an estimate of OCD prevalence in pregnant and postpartum women and synthesizes the evidence that pregnant and postpartum women are at greater risk of OCD compared to the general population. Data Sources: An electronic search of Google Scholar, PsycINFO, PsychARTICLES, and PubMed was performed by using the search terms OCD, obsessive-compulsive disorder, pregnancy, postpartum, prevalence, and epidemiology. We SUPPLemented our search with articles referenced in the obtained sources. The search was conducted until August 2012 without date restrictions. Study Selection: We included English-language studies reporting OCD prevalence (diagnosed according to DSM-III-R, DSM-IV, or ICD-10 criteria) in pregnant (12 studies) or postpartum (up to 12 months; 7 studies) women using structured diagnostic interviews. We also included a sample of regionally matched control studies (10 studies) estimating 12-month prevalence in the general female population for comparison. The control studies were limited to those conducted during the same time frame as the pregnant and postpartum studies. Data Extraction: We extracted author name, year of publication, diagnostic measure, sample size, diagnostic criteria, country, assessment time, subject population, and the point prevalence of OCD. Results: Mixed- and random-effects models revealed an increase in OCD prevalence across pregnancy and the postpartum period with the lowest prevalence in the general population (mean = 1.08%) followed by pregnant (mean = 2.07%) and postpartum women (mean = 2.43%). An exploratory analysis of regionally matched risk-ratios revealed both pregnant (mean = 1.45) and postpartum (mean = 2.38) women to be at greater risk of experiencing OCD compared to the general female population, with an aggregate risk ratio of 1.79. Conclusions: Pregnant and postpartum women are more likely to experience OCD compared to the general population. © Copyright 2013 Physicians Postgraduate Press, Inc.
Huismans R.S.,University of Bergen |
Beaumont C.,Dalhousie University
Earth and Planetary Science Letters | Year: 2014
Even though many basic properties of non-volcanic rifted margins are predicted by uniform extension of the lithosphere, uniform extension fails to explain other important characteristics. Particularly significant discrepancies are observed at: 1) the Iberia-Newfoundland conjugate margins (Type I), where large tracts of continental mantle lithosphere are exposed at the seafloor, and at 2) ultra-wide central South Atlantic margins (Type II) where continental crust spans wide regions below which it appears that lower crust and mantle lithosphere were removed. Neither corresponds to uniform extension in which crust and mantle thin by the same factor. Instead, either the crust or mantle lithosphere has been preferentially removed during extension. We show that the Type I and II styles are respectively reproduced by dynamical numerical lithospheric stretching models (Models I-A/C and II-A/C) that undergo depth-dependent extension. In this notation A and C imply underplating of the rift zone during rifting by asthenosphere and lower cratonic lithosphere, respectively. We also present results for models with a weak upper crust and strong lower crust, Models III-A/C, to show that lower crust can also be removed from beneath the rift zone by horizontal advection with the mantle lithosphere. From the model results we infer that these Type I, II, and III margin styles are controlled by the strength of the mid/lower crust, which determines the amount of decoupling between upper and lower lithosphere during extension and the excision of crust or mantle. We also predict the styles of sedimentary basins that form on these margins as a test of the concepts presented. © 2014 Elsevier B.V.
Lauzon-Guay J.-S.,Maurice Lamontagne Institute |
Scheibling R.E.,Dalhousie University
Marine Ecology Progress Series | Year: 2010
On the Atlantic coast of Nova Scotia, transitions between alternative states of the subtidal ecosystem, kelp beds and sea urchin barrens, occur on a decadal scale. To explore the process of urchin aggregation within kelp beds that leads to the shift to barrens, we developed a coupled map lattice model to simulate the spatial dynamics of kelp and green sea urchin Strongylocentrotus droebachiensis abundance over time. Our simulations show that the following factors can cause sea urchins to form grazing aggregations that create gaps in a kelp bed: (1) random movement by >60% of sea urchins residing in the bed, (2) moderate to high levels of spatial variability in sea urchin recruitment (30 to 90 [urchins m-2]2), (3) localized aggregation of sea urchins (150 urchins m-2) amid a moderate to high background density of sea urchins within the kelp bed (>10 urchins m-2), with or without a chemotactic response of sea urchins to kelp, and (4) removal of kelp from areas >20 m2 (to simulate physical or biological disturbance, or harvesting). Gaps formed at random locations within the spatial domain and expanded and coalesced to form barrens in which sea urchins were randomly distributed. Sea urchins formed circular fronts around gaps in the kelp bed. The rate of advance of fronts (and increase in gap size) was linearly related to the density of sea urchins at the front. The duration of the transition to the barrens state decreased with increases in (1) the proportion (Pm) of sea urchins moving (from >6 yr for Pm = 0.8 to <2 yr for P m = 1) and (2) the variance of sea urchin recruitment (from >5 yr for 30 [urchins m-2]2 to >3 yr for 90 [urchins m -2]2). Our findings support observations of gap formation within kelp beds that resulted in widespread destructive grazing on this coast in the late 1960s. Our model provides a predictive tool for the design of monitoring programs and field experiments to explore the underlying mechanisms of an ecosystem phase shift that has major ecological consequences. © Inter-Research 2010.
Scheibling R.E.,Dalhousie University |
Lauzon-Guay J.-S.,Maurice Lamontagne Institute
Limnology and Oceanography | Year: 2010
An increase in the incidence of disease in various marine organisms over the past few decades has been linked to ocean climate change. In Nova Scotia, Canada, mass mortalities of sea urchins, due to an amoebic disease, are associated with tropical cyclones of relatively high intensity that pass close to the coast when water temperature is above a threshold for disease propagation. These conditions increase the likelihood of introduction and spread of a nonindigenous water-borne pathogen through turbulent mixing. Our analysis shows that the most deadly storms, in terms of the probability of a sea urchin mass mortality, have become more deadly over the past 30 years. We also found that storms have been tracking closer to the coast and that surface temperature has increased during the hurricane season. These trends are likely to continue with climate warming, resulting in a regional shift to a kelp bed ecosystem and the loss of the urchin fishery. © 2010, by the American Society of Limnology and Oceanography, Inc.
Smith D.R.,University of Western Ontario |
Lee R.W.,Dalhousie University
Plant Physiology | Year: 2014
Polytomella spp. are free-living, nonphotosynthetic green algae closely related to the model organism Chlamydomonas reinhardtii. Although colorless, Polytomella spp. have a plastid, but it is still unknown whether they harbor a plastid genome. We took a next generation sequencing approach, along with transcriptome sequencing, to search for a plastid genome and an associated gene expression system in Polytomella spp. Illumina sequencing of total DNA from four Polytomella spp. did not produce any recognizable plastid-derived reads but did generate a large number of mitochondrial DNA sequences. Transcriptomic analysis of Polytomella parva uncovered hundreds of putative nuclear-encoded, plastid-targeted proteins, which support the presence of plastid-based metabolic functions, similar to those observed in the plastids of other nonphotosynthetic algae. Conspicuously absent, however, were any plastid-targeted proteins involved in the expression, replication, or repair of plastid DNA. Based on these findings and earlier findings, we argue that the Polytomella genus represents the first wellsupported example, to our knowledge, of a primary plastid-bearing lineage without a plastid genome. © 2014 American Society of Plant Biologists. All Rights Reserved.
Tong X.,University of Hong Kong |
Deacon S.H.,Dalhousie University |
Cain K.,Lancaster University
Journal of Learning Disabilities | Year: 2014
Poor comprehenders have intact word-reading skills but struggle specifically with understanding what they read. We investigated whether two metalinguistic skills, morphological and syntactic awareness, are specifically related to poor reading comprehension by including separate and combined measures of each. We identified poor comprehenders (n = 15) and average comprehenders (n = 15) in Grade 4 who were matched on word-reading accuracy and speed, vocabulary, nonverbal cognitive ability, and age. The two groups performed comparably on a morphological awareness task that involved both morphological and syntactic cues. However, poor comprehenders performed less well than average comprehenders on a derivational word analogy task in which there was no additional syntactic information, thus tapping only morphological awareness, and also less well on a syntactic awareness task, in which there were no morphological manipulations. Our task and participant-selection process ruled out key nonmetalinguistic sources of influence on these tasks. These findings suggest that the relationships among reading comprehension, morphological awareness, and syntactic awareness depend on the tasks used to measure the latter two. Future research needs to identify precisely in which ways these metalinguistic difficulties connect to challenges with reading comprehension. © Hammill Institute on Disabilities 2013.
Roy M.M.,Lakehead University |
Dutta A.,University of Guelph |
Corscadden K.,Dalhousie University
Applied Energy | Year: 2013
This study presents combustion and emission results obtained using a prototype pellet furnace with 7-32kW capacity (designed for burning high ash content pellet fuels) for four biomass pellets: one grass pellet and three wood pellets. Fuel property, gas emissions and furnace efficiency are compared. In regard to fuel properties, proximate analysis, ultimate analysis and heating values are determined and emissions of carbon monoxide (CO), nitric oxide (NO), nitrogen dioxide (NO2), nitrogen oxides (NOx) and sulfur dioxide (SO2) are measured and compared. Scanning electron microscopy (SEM) was used for ash analysis. No ash agglomeration was observed and ash discharge was in the form of powder instead of lumped particles, which are usually observed for high ash biomass fuel. The results suggest that grass pellets can successfully be combusted with similar performance and emissions to that of other wood pellets if burned in appropriate combustion installations. © 2013 Elsevier Ltd.
Andrade C.,National Institute of Mental Health and Neuro Sciences |
Kisely S.,University of Queensland |
Monteiro I.,National Institute of Mental Health and Neuro Sciences |
Rao S.,Dalhousie University
Journal of Psychiatric Research | Year: 2015
We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) of modafinil or armodafinil (ar/mod) augmentation in schizophrenia. We searched PubMed, clinical trial registries, reference lists, and other sources for parallel group, placebo-controlled RCTs. Our primary outcome variable was the effect of ar/mod on negative symptom outcomes. Eight RCTs (pooled N=372; median duration, 8 weeks) met our selection criteria. Ar/mod (200mg/day) significantly attenuated negative symptom ratings (6 RCTs; N=322; standardized mean difference [SMD],-0.26; 95% CI,-0.48 to-0.04). This finding remained similar in all but one sensitivity analysis - when the only RCT in acutely ill patients was excluded, the outcome was no longer statistically significant (SMD,-0.17; 95% CI,-0.51 to 0.06). The absolute advantage for ar/mod was small: just 0.27 points on the PANSS-N (6 RCTs). Ar/mod attenuated total psychopathology ratings (7 RCTs; N=342; SMD,-0.23; 95% CI,-0.45 to-0.02) but did not influence positive symptom ratings (5 RCTs; N=302; mean difference,-0.58; 95% CI,-1.71 to 0.55). Although data were limited, cognition, fatigue, daytime drowsiness, adverse events, and drop out rates did not differ significantly between ar/mod and placebo groups. Fixed and random effects models yielded similar results. There was no heterogeneity in all but one analysis. Publication bias could not be tested. We conclude that ar/mod (200mg/day) is safe and well tolerated in the short-term treatment of schizophrenia. Ar/mod reduces negative symptoms with a small effect size; the absolute advantage is also small, and the advantage disappears when chronically ill patients or those with high negative symptom burden are treated. Ar/mod does not benefit or worsen other symptom dimensions in schizophrenia. © 2014 Elsevier Ltd.
Sherwin S.B.,Dalhousie University |
Winsby M.,University of Western Ontario
Health Expectations | Year: 2011
Aim To review critically the traditional concept of autonomy, propose an alternative relational interpretation of autonomy, and discuss how this would operate in identifying and addressing ethical issues that arise in the context of nursing home care for older adults. Background Respect for patient autonomy has been the cornerstone of clinical bioethics for several decades. Important though this principle is, there is debate on how to interpret the core concept of autonomy. We review the appeal of the traditional approach to autonomy in health care and then identify some of the difficulties with this conception. Methods We use philosophical methods to explain and discuss the traditional and relational conceptions of autonomy and we illuminate our discussion with examples of various contextual applications. Conclusion We support the relational conception of autonomy as offering a richer, more contextualized understanding of autonomy which attends to the social, political and economic conditions that serve as background to an agent's deliberations. To illuminate these ideas, we discuss the situation of frail older adults who frequently find their autonomy limited not only by their medical conditions but also by cultural prejudices against the aged and by the conditions commonly found within the nursing homes in which many reside. We propose ways of improving the relational autonomy of this population. © 2010 Blackwell Publishing Ltd.
Westwood D.A.,Dalhousie University |
Goodale M.A.,University of Western Ontario
Vision Research | Year: 2011
In 1992, Goodale and Milner proposed the existence of a dedicated visuomotor control system that allows for the control of action without the need for conscious perception of the target object's form. The 'action and perception hypothesis' was motivated in large part by the surprising observation of spared visuomotor abilities in D.F., a patient with a severe deficit in visual form perception attributable to a lesion concentrated in the lateral occipital complex of the ventral stream. When D.F. reaches out to grasp an object, her hand posture in flight reflects the size, shape, and orientation of the object, despite the fact that she is unable to report those same object features. Nevertheless, there are systematic limits to her spared ability to grasp objects: her performance sharply deteriorates for objects defined by second-order contrast, objects whose principal axis of orientation is ambiguous, objects removed from view before the onset of the action, and objects seen without cues to absolute distance. At the same time, a considerable body of psychophysical evidence from healthy observers has accumulated that is consistent with the idea of a dedicated visuomotor control system that is independent of perceptual influence. Although some of this evidence is controversial, we will argue that, on balance, there is good agreement between the psychophysical and neuropsychological data - and that the action and perception hypothesis is still alive and well. © 2010 Elsevier Ltd.
Roy M.M.,Lakehead University |
Corscadden K.W.,Dalhousie University
Applied Energy | Year: 2012
This study presents combustion and emission results obtained using an Environmental Protection Agency (EPA) phase two wood stove for 15 biomass briquettes produced from a range of feedstock including hay and switch grass. Fuel property, gas emissions, particulate emissions and stove efficiency are compared. In regard to fuel properties, proximate analysis, ultimate analysis and heating values are determined and emissions of carbon monoxide (CO), nitrogen oxides (NOx) and sulfur dioxide (SO2) are measured and compared. In this study, particulates are sampled, measured and compared using an isokinetic particulate analyser. The results suggest that hay and switch grass briquettes can successfully be combusted in domestic wood stoves with similar performance and emissions to that of other woody briquettes. © 2012 Elsevier Ltd.
Fraser C.I.,Roosevelt University |
Nikula R.,University of Otago |
Ruzzante D.E.,Dalhousie University |
Waters J.M.,University of Otago
Trends in Ecology and Evolution | Year: 2012
Postglacial recolonisation patterns are well documented for the Northern Hemisphere biota, but comparable processes in the Southern Hemisphere have only recently been examined. In the largely terrestrial Northern Hemisphere, recession of ice after the Last Glacial Maximum (LGM) allowed various taxa, including slow-moving terrestrial species, to migrate poleward. By contrast, the Southern Hemisphere polar region is completely ringed by ocean, and recolonisation of Antarctica and the sub-Antarctic islands has thus presented considerable challenges. Although a few highly dispersive marine species have been able to recolonise postglacially, most surviving high-latitude taxa appear to have persisted throughout glacial maxima in local refugia. These contrasting patterns highlight the importance of habitat continuity in facilitating biological range shifts in response to climate change. © 2012 Elsevier Ltd.
News Article | November 15, 2016
Nova Scotia-based cricket farm set to become a leading provider of sustainable alternative protein for pet food products MISSISSAUGA, ON--(Marketwired - November 15, 2016) - Dane Creek Capital Corp. ('DCCC' or the 'Company'), a merchant banking venture that focuses on pet industry investments, is pleased to announce it has acquired a 48% interest in Midgard Insect Farm Inc. ('Midgard'), a cricket producer headquartered in Windsor, Nova Scotia. Midgard crickets are a featured ingredient in the Company's Dockside brand of planet friendly pet treats, meal mixers, and meal toppers for dogs and cats created using ingredients from rescued fresh food and sustainable sources. DCCC's investment will also facilitate research and development aimed at growing Midgard's business to become a leading wholesaler to pet industry companies looking to incorporate insect protein into their products. Midgard is one of a growing number of companies raising insects as an alternative and sustainable source of protein for both human and animal consumption. Whereas cricket farms have traditionally focused on the sale of live crickets for pet specialty retail, Midgard's model will focus exclusively on the production of whole ground cricket meal to satisfy growing demand for alternative proteins in the pet food industry. Over the course of the next 18 months, the Company expects the expansion of Midgard's production capacity and ancillary operations will generate up to 15 new jobs for the local economy. Midgard was founded and is currently operated by Joy Hillier, a registered veterinary technician and graduate of Dalhousie University's Agricultural College whose interest in food security and sustainability led to her interest in edible insects. She also has professional experience in the food industry, animal husbandry, biosecurity technology, and laboratory procedure. Through her partnership with DCCC, Hillier joins the ranks of women entrepreneurs closing the gender gap on securing capital investment in North America. Studies indicate only 10% of venture capital has been allotted to female founded startups spanning back to 2010 of which those in science and technology are particularly challenged. "We are very pleased to be making this announcement," says Mark Warren, Chairman & CEO of DCCC. "We recognised early on it would be important for us to vertically integrate our sources of sustainable ingredients for the Dockside brand of pet products. Additionally, as sustainability becomes a leading concern among pet owners, we believe there will be opportunities to expand the business to provide cricket protein to the pet industry as a whole. We were very impressed with Joy and her unique blend of scientific curiosity and entrepreneurial savvy and are excited to be given this opportunity to help her grow her business." An immediate result of the partnership will be the establishment of a 1,500 square foot research facility for Midgard in association with Perennia, a non-profit corporation in Bible Hill, Nova Scotia dedicated to helping the province's farmers, fishers, and food processors prosper. This second Midgard location will allow Hillier to work closely with Perennia's team of food research scientists and nutritionists to produce top quality cricket meal with an initial focus on consistency, an issue which has challenged the industry. The collaboration marks an extension of the Company's existing relationship with Perennia involving ongoing research and development into Dockside sustainable pet food products. "I am very excited to welcome Dane Creek as an equity partner in my venture," says Hillier. "Their support for my vision coupled with their pet industry and business management expertise will allow me to focus my time and energy on the developing science of cricket production and creating a high quality product for the pet food industry that will improve its sustainability as a whole. They will also be a valuable asset as we look to increase production and start hiring and training new personnel over the next year." Crickets as an alternative protein source offer both environmental and nutritional benefits. According to the Food & Agriculture Organization of the United Nations, crickets are twice as efficient as chicken and six times more efficient than cattle at converting feed to protein. They also consume far less water, approximately 1/2000th the volume required to produce the same amount of beef, and require less space. Nutritionally, crickets provide an easily digestible protein and a complete source of all the essential amino acids dogs and cats require, including taurine. They also provide calcium, omega-3 fatty acids, and prebiotic chitin, and contain higher levels of iron and magnesium than beef on a pound for pound basis. Negotiations between DCCC and Midgard were facilitated by Perennia, the Atlantic Canada Opportunities Agency, and Nova Scotia Business Inc., a private-sector business development agency. DCCC's equity stake is held by Dockside Investco, its wholly owned holding company in Nova Scotia. Financial terms were not announced. With over 30 years of experience in the pet industry and an extensive network of industry professionals, we offer valuable financial and management support to up-and-coming companies in the companion animal sector through selective, strategic investments. Our investment horizon is long-term taking into account current trends and changes in pet owner demographics with a current focus on opportunities in pet food products sourced from sustainable ingredients, alternative models for veterinary care, biotechnology, pet insurance, pet hotels, and pet-related technological applications for pet owners.
Chen H.,China University of Mining and Technology |
Gu J.J.,Dalhousie University
IEEE/ASME Transactions on Mechatronics | Year: 2010
This paper presents two three-phase switched reluctance machine systems. One is the dual motors drive for the electric locomotive traction; the other is the variable-speed generator system for wind power applications. The principles of the switched reluctance machine system operated at four quadrants, the scheme of the symmetrical traction at quadrant I and quadrant III, and the scheme of the symmetrical regenerative braking control at quadrant II and quadrant IV, are given. The transient phase current analysis and the energy analysis of the switched reluctance machine system at the operational state of braking or generating are evaluated, and the rotor position and the peak value of the phase current at three different conditions are given. The closed-loop rotor speed control of the main motor, synchronization of the rotor speed, and balance distribution of loads between the main motor and the subordinate motor have been implemented by the fuzzy logic algorithm. The closed-loop output power control of the switched reluctance wind power generator system implemented by regulating the turn-on angle of the main switches with fuzzy logic algorithm and fixed turn-off angle of the main switches is also presented. The major components of the two prototypes are explained in detail. The experimental results of the dual 7.5-kW three-phase 6/4 structure switched reluctance motors (SRMs) parallel drive system prototype are included. It is shown that the maximum difference in the output torque of the two motors at the same given rotor speeds is within 10.00 and the maximum difference in the practical rotor speed of the two motors is within 5.00. The tested results of three-phase 12/8 structure switched reluctance variable-speed wind power generator system show that the error of the closed-loop output power control is within 2.2, while the rotor speed range is close to the ratio of 1:3 with the low rotor speed 405 r/min. The average dc line current of the power converter can be utilized as a feedback signal for the actual output torque of SRM drive or a feedback signal for the actual output power of switched reluctance generator system. © 2006 IEEE.
Obrovac M.N.,Dalhousie University |
Chemical Reviews | Year: 2014
Most studies set out to make materials that improve on the specific capacity of graphite, usually without regard to average voltage, volumetric capacity, or the many other properties listed above that are more applicable to implementation in practical cells. One difficulty in choosing proper metrics for anodes stems from basic electrochemistry: it is not possible to calculate the energy of a single electrode. To provide motivation for using alloy anode materials and a framework for comparison, key performance metrics need to be defined. It is well-known that the volumetric and specific capacities of the active elements are far greater than that of graphite. Because all alloys expand considerably during lithiation, this volume must be accommodated somewhere within a battery. To make more informative performance comparisons, it is necessary to use a cell model, preferably one that is most representative of alloy materials application.
Pearce J.A.,University of Cardiff |
Robinson P.T.,Dalhousie University
Gondwana Research | Year: 2010
Miyashiro (1973) famously initiated a debate on the tectonic setting of ophiolite complexes by proposing that 'the Troodos ophiolitic complex was probably formed in an island arc'. This paper evaluates and updates Miyashiro's work by: (a) using the Mehegan-Robinson set of 137 fresh volcanic glass analyses to sidestep the controversy over the effect of alteration on major element classification diagrams; (b) using the volcanic glass database for Troodos analogues such as back-arc basins, slab edges, forearcs and subduction initiation terranes; (c) revising Miyashiro's classifications by including the boninitic series and subdividing the tholeiitic series into high- and medium-Fe series; and (d) extending Miyashiro's methodologies to new developments in the interpretation of major element data. We conclude that the Troodos Massif is made up of oceanic crust built from a high-Si8, moderate-Fe tholeiitic magma, overlain by boninites. Its low K8/H8 is consistent with near-trench crustal accretion and its Na8-Fe8 systematics indicate that TP = c.1400 °C for the Lower Lavas, consistent with rapid slab roll-back and/or sideways influx of hot mantle. Overall, the geochemical characteristics and geological setting support models in which the Troodos Massif formed by slab roll-back following subduction initiation, probably near a slab edge. © 2009 International Association for Gondwana Research.
Chen H.,China University of Mining and Technology |
Gu J.J.,Dalhousie University |
Gu J.J.,Shandong University
IEEE/ASME Transactions on Mechatronics | Year: 2013
This paper describes the developed three-phase 6/8 poles switched reluctance external rotor motor drive for a fan in air conditioner. The external rotor core structure and the internal stator core structure, the three-phase windings arrangement, the slotted claw, and the setting structure of the photoelectric transducers on the rotor position detector are illustrated. The electromagnetic field calculation results are given. The three-phase asymmetric bridge power converter was used in the drive system. The block diagram of the switched reluctance external rotor motor drive with closed-loop rotor speed control is given. The closed-loop rotor speed control is implemented using a fuzzy logic algorithm. The experimental tests of the developed prototype are made for driving the fan from 200 to 950 r/min. The comparison results of the two systems show that the input power and input phase current RMS value are lower in the developed three-phase 6/8 poles external rotor switched reluctance motor drive prototype with the fan than those in the induction motor variable-frequency variable-speed drive with the fan. © 1996-2012 IEEE.
Yuet P.K.,Dalhousie University |
Blankschtein D.,Massachusetts Institute of Technology
Journal of Physical Chemistry B | Year: 2010
Molecular dynamics (MD) simulation has been used extensively to study water surfaces. Nevertheless, the quantitative prediction of water surface tension has been controversial, since results from different simulation studies using the same water model may differ considerably. Recent research has suggested that bond flexibility, long-range electrostatic interactions, and certain simulation parameters, such as Lennard-Jones (LJ) cutoff distance and simulation time, may play an important role in determining the simulated surface tension. To gain better insight on the MD simulation of water surfaces, particularly on the prediction of surface tension, we examined seven flexible water models using a consistent set of simulation parameters. The surface tensions of the flexible, extended simple point charge (SPCE-F) model and the flexible three-center (F3C) model at 300 K were found to be 70.2 and 65.3 mN/m, respectively, in reasonable agreement with the experimental value of 71.7 mN/m. More importantly, however, detailed analysis of the interfacial structure and contributions from various interactions have revealed that the surface tension of water is determined by the delicate balance between intramolecular (bond stretching) and intermolecular (LJ) interactions, which reflects both the molecular orientation in the interfacial region and the density variation across the Gibbs dividing surface (GDS). In addition, the water molecules on the liquid side of the GDS were found to lie almost parallel to the surface, which helps to clarify the dual-layer structure suggested by sum-frequency generation spectroscopy. By correlating the simulated surface tensions of the seven water models with selected molecular parameters, it was found that the partial charge distribution in the water molecule is likely a key factor in determining the near-parallel alignment of water molecules with the surface. © 2010 American Chemical Society.
News Article | March 1, 2017
Acknowledgement of Indigenous lands, treaties and peoples vary at universities across Canada, finds a new study from the University of British Columbia, the first academic study of its kind. The study identified five different types of acknowledgement at universities in B.C., the Prairies, Ontario, Quebec and the Atlantic. These acknowledgements are typically made at official events or ceremonies at each institution to recognize the Indigenous communities whose lands upon which the universities sit. Acknowledgements are becoming more common as post-secondary institutions make Indigenous engagement a priority. "Acknowledgements indicate respect for Indigenous communities and bring attention to an often ignored history," said co-author Linc Kesler, director of UBC's First Nations House of Learning and associate professor in English and First Nations and Indigenous Studies. "It sets a context for present relationships among Indigenous and non-Indigenous peoples that can be thought of in a more deliberate way." The researchers searched almost 100 university websites for official acknowledgements, looking for key words like "Indigenous", "Aboriginal" and "First Nations", among others, and contacted university representatives to confirm the information. Acknowledgement was defined as a "complicated term, at times referring to a recognition of truth or existence and at other times implying gratitude or appreciation." The study finds university acknowledgement in B.C. focuses on land and title as much of the province is considered unceded, or land that was never surrendered. In the Prairie provinces of Alberta, Saskatchewan and Manitoba, specific treaties between several First Nations and the governments are emphasized. In Ontario, acknowledgements are centered on offering the "the most diverse content" and a focus on multiculturalism. In Quebec, no official practice was found. In the Atlantic, acknowledgements are not as formalized but prioritize people and territory. "We can only speculate as to why the acknowledgments differ so greatly, but regional histories and provincial politics could be significant factors," said co-author Rima Wilkes, a UBC sociology professor. "Acknowledgement practices are constantly evolving and we saw that in our research. Our study is part of a conversation that we need to be having more of, particularly when we are visitors to different places and we're not familiar with the local issues or histories." The researchers also question whether or not acknowledgement helps promote reconciliation or merely acts as a "tokenistic practice of checking the box." "Acknowledgements are not necessarily a measure of institutional commitment past a certain point," said Kesler. "It's a starting point. How the acknowledgement is used, how it's developed and how it reflects in more deeper terms what institutions are doing to engage with Indigenous communities is the more important question." The study, "Canadian University Acknowledgement of Indigenous Lands, Treaties and Peoples", was published recently in Canadian Review of Sociology. The study is co-written by Linc Kesler and Rima Wilkes of UBC, former UBC student Aaron Duong, now a graduate student at the University of Alberta and political sociologist Howard Ramos of Dalhousie University. Read the full study here: http://wp. The acknowledgment practices that were analyzed in the study were found between 2014 to 2016. UBC recognizes its Vancouver and Kelowna campuses are situated on the traditional, ancestral and unceded territories of the Musqueam Indian Band and the Okanagan First Nation. UBC Robson Square is located on the unceded territory of the Musqueam, Squamish and Tsleil-Waututh First Nations. For information about UBC's acknowledgment practices, click here: http://aboriginal.
News Article | October 26, 2016
SMALL island nations are at risk of severe drought as climate change causes sea levels to rise. Groundwater supplies are salinated as the sea swamps coastal areas, but there’s another problem inland, where fresh water is being pushed above ground and vanishing into thin air. As the seas rise, they not only lap higher up the beach but also raise the level of the groundwater – sometimes above low points on the surface. This can cause existing lakes to expand and new ones to form, which speeds up evaporation. “Lots of work so far has focused on coastal inundation,” says Jason Gulley at the University of South Florida in Tampa. “But there has been less focus on interior indentations that flood as sea-level rise pushes the water table higher.” Gulley’s team used computer simulations of islands similar to those in the southern Bahamas to show that such lake formation reduces groundwater resources more than twice as much as coastal inundation for a given amount of sea-level rise (Geophysical Research Letters, doi.org/brwx). “Arid regions are going to get substantial losses of fresh water,” says Gulley. Although just a small number of islands might be affected, the consequences could be severe, says Shannon Sterling at Dalhousie University in Halifax, Canada. “This is significant,” she says, “because reductions in available water are occurring in already water-limited sensitive areas, with potentially large economic and human consequences.” Gulley says the next step is to take his simulated results and figure out which real-life islands are most susceptible. But that will not be easy. “It’s more complicated than just predicting how much coastline will be flooded,” he says. “It will require deep, island-specific knowledge of topography.” This article appeared in print under the headline “New lakes drain drinking water as islands sink”
News Article | December 17, 2016
The ability to forecast tomorrow’s weather is something farmers have at their fingertips in many parts of the world, but in some regions weather forecasting is much trickier. “In the tropics, weather processes are faster and up to a thousand times smaller than up here,” says Liisa Petrykowska, managing director of Ignitia, a Stockholm-based startup. “The weather forecasting systems developed by western governments haven’t focused on the tropics.” Existing next-day forecasts are accurate less than half the time, she says, making them next-to-useless for farmers. Ignitia has built its own atmospheric models to deliver forecasts that are right up to 85% of the time, and sends them out as simple text messages costing just 4 cents (2p) a day. “Many farmers were sceptical at first,” says Petrykowska, “But we quickly built up trust. Now 90% of Ghanaian farmers who receive them say the forecasts have helped them to make the correct decisions about planting, sowing, spraying and transportation.” Ignitia was one of a number of food tech startups that gathered in Stockholm last week for the Future of Food, an event organised by the Nobel Foundation. The startups believe applying technologies such as machine learning, advanced materials and open-source practices can revolutionise food production. “What happens in the next 50 years will determine what happens to society over the next 10,000,” Johan Rockström, professor of environmental science at Stockholm University, told the conference. “Food is the deciding factor. Food is the primary cause behind loss of diversity, the largest user of fresh water, and is responsible for 30% of all greenhouse gas emissions. If we get it right on food, we are likely to get it right for planet Earth.” Caleb Harper, director of Open Agriculture at the Massachusetts Institute of Technology, thinks sensor-controlled hydroponic and aeroponic growing systems are part of the answer. “We are slaves to climate in agriculture. But what if we could give every country access to good weather?” he said. In his lab, plants grow under LED lights and the watchful gaze of dozens of sensors – collecting more than 3m data points for every plant. Harper claims his crops grow five times faster than they would outdoors, and need 90% less water while doing so. Everything his lab discovers is then made freely available through open source hardware and software websites. “The open food movement gives access to biology, in the same way that HTML gave us access to the internet,” says Harper. Aside from weather, another big topic at the event was the shift away from raising animals for meat, which is responsible for a disproportionate share of the land, water and energy used in food production. “Americans eat four times as much beef as all seafood combined, but aquaculture is emerging as a possible solution,” says Peter Tyedmers of Dalhousie University in Canada. He has been evaluating new, floating semi-closed fish farming tanks that can recycle fish waste as fertiliser and avoid contaminating nearby water systems. One drawback is that they need more energy than traditional open-water farms, meaning they might increase carbon emissions even as they reduce pollution. Tyedmers also warns that fish food should be sourced from low-impact agricultural crops rather than other marine organisms. “Aquaculture is not a panacea but it can be a key wedge in moving away from land-fed livestock to the sea,” he says. Food technology is also giving us solutions at home. As more people use online grocery or meal services, there has been a growing demand for refrigerated lorries, together with expensive Styrofoam boxes and gel packs to keep food hot or cold on that last mile. The Food Climate Research Network estimates around half a percent of the UK’s greenhouse gas emissions come from mobile refrigeration units moving chilled food around the country. iFoodbag, another Stockholm startup, aims to replace traditional delivery methods with reusable, recyclable bags made from laminated paper. The bag can keep chilled groceries from becoming dangerously warm for around five hours, which its makers think is long enough to use a normal van (or presumably a drone, in the future) for delivery. Adding a frozen gel pack extends the time to eight hours, and the bag can be reused up to seven times. Sign up to be a Guardian Sustainable Business member and get more stories like this direct to your inbox every week. You can also follow us on Twitter.
Boates B.,Dalhousie University |
Boates B.,Lawrence Livermore National Laboratory |
Bonev S.A.,Dalhousie University |
Bonev S.A.,Lawrence Livermore National Laboratory
Physical Review Letters | Year: 2013
The phase diagrams of MgSiO3 and MgO are studied from first-principles theory for pressures and temperatures up to 600 GPa and 20 000 K. Through the evaluation of finite-temperature Gibbs free energies, using density-functional theory within the generalized gradient approximation as well as with hybrid exchange-correlation functionals, we find evidence for a vast pressure-temperature regime where molten MgSiO3 decomposes into liquid SiO2 and solid MgO, with a volume change of approximately 1.2%. The demixing transition is driven by the crystallization of MgO - the reaction only occurs below the high-pressure MgO melting curve. The predicted transition pressure at 10 000 K is in close proximity to an anomaly reported in recent laser-driven shock experiments of MgSiO3. We also present new results for the high-pressure melting curve of MgO and its B1-B2 solid phase transition, with a triple point at 364 GPa and 12 000 K. © 2013 American Physical Society.
MacInnis M.C.,Dalhousie University |
McDonald R.,University of Alberta |
Ferguson M.J.,University of Alberta |
Tobisch S.,University of St. Andrews |
Turculet L.,Dalhousie University
Journal of the American Chemical Society | Year: 2011
Unprecedented diamagnetic, four-coordinate, formally 14-electron (Cy-PSiP)RuX (Cy-PSiP = [κ 3-(2-R 2PC 6H 4) 2SiMe] -; X = amido, alkoxo) complexes that do not require agostic stabilization and that adopt a highly unusual trigonal pyramidal coordination geometry are reported. The tertiary silane [(2-Cy 2PC 6H 4) 2SiMe]H ((Cy-PSiP)H) reacted with 0.5 [(p-cymene)RuCl 2] 2 in the presence of Et 3N and PCy 3 to afford [(Cy-PSiP)RuCl] 2 (1) in 74% yield. Treatment of 1 with KO tBu led to the formation of (Cy-PSiP)RuO tBu (2, 97% yield), which was crystallographically characterized and shown to adopt a trigonal pyramidal coordination geometry in the solid state. Treatment of 1 with NaN(SiMe 3) 2 led to the formation of (Cy-PSiP)RuN(SiMe 3) 2 (3, 70% yield), which was also found to adopt a trigonal pyramidal coordination geometry in the solid state. The related anilido complexes (Cy-PSiP)RuNH(2,6-R 2C 6H 3) (4, R = H; 5, R = Me) were also prepared in >90% yields by treating 1 with LiNH(2,6-R 2C 6H 3) (R = H, Me) reagents. The solid state structure of 5 indicates a monomeric trigonal pyramidal complex that features a C-H agostic interaction. Complexes 2 and 3 were found to react readily with 1 equiv of H 2O to form the dimeric hydroxo-bridged complex [(Cy-PSiP)RuOH] 2 (6, 94% yield), which was crystallographically characterized. Complexes 2 and 3 also reacted with 1 equiv of PhOH to form the new 18-electron n 5-oxocyclohexadienyl complex (Cy-PSiP)Ru(n 5-C 6H 5O) (7, 84% yield). Both amido and alkoxo (Cy-PSiP)RuX complexes reacted with H 3B·NHRR′ reagents to form bis(δ-B-H) complexes of the type (Cy-PSiP)RuH(n 2:· 2-H 2BNRR′) (8, R = R′ = H; 9, R = R′ = Me; 10, R = H, R′ = tBu), which illustrates that such four-coordinate (Cy-PSiP)RuX (X = amido, alkoxo) complexes are able to undergo multiple E-H (E = main group element) bond activation steps. Computational methods were used to investigate structurally related PCP, PPP, PNP, and PSiP four-coordinate Ru complexes and confirmed the key role of the strongly δ-donating silyl group of the PSiP ligand set in enforcing the unusual trigonal pyramidal coordination geometry featured in complexes 2-5, thus substantiating a new strategy for the synthesis of low-coordinate Ru species. The mechanism of the activation of ammonia-borane by such low-coordinate (R-PSiP)RuX (X = amido, alkoxo) species was also studied computationally and was determined to proceed most likely in a stepwise fashion via intramolecular deprotonation of ammonia and subsequent borane B-H bond oxidative addition steps. © 2011 American Chemical Society.
Teweldeberhan A.M.,Lawrence Livermore National Laboratory |
Dubois J.L.,Lawrence Livermore National Laboratory |
Bonev S.A.,Lawrence Livermore National Laboratory |
Bonev S.A.,Dalhousie University
Physical Review Letters | Year: 2010
The phase diagram of Ca is examined using a combination of density-functional theory (DFT) and diffusion quantum Monte Carlo (DMC) calculations. Gibbs free energies of several competing structures are computed at pressures near 50 GPa. Existing disagreements for the stability of Ca both at low and room temperature are resolved with input from DMC. Furthermore, DMC calculations are performed on 0 K crystalline structures up to 150 GPa and it is demonstrated that the widely used generalized gradient approximation of DFT is insufficient to accurately account for the relative stability of the high-pressure phases of Ca. The results indicate that the theoretical phase diagram of Ca needs a revision. © 2010 The American Physical Society.
Bernatsky S.,McGill University |
Linehan T.,Dalhousie University |
Hanly J.G.,Dalhousie University
Journal of Rheumatology | Year: 2011
Objective. To examine the validity of case definitions for systemic autoimmune rheumatic diseases [SARD; systemic lupus erythematosus (SLE), systemic sclerosis (SSc), myositis, Sjögren's syndrome, vasculitis, and polymyalgia rheumatica] based on administrative data, compared to rheumatology records. Methods. A list of rheumatic disease diagnoses was generated from population-based administrative billing and hospitalization databases. Subjects who had been seen by an arthritis center rheumatologist were identified, and the medical records reviewed. Results. We found that 844 Nova Scotia residents had a diagnosis of one of the rheumatic diseases of interest, based on administrative data, and had had ≥ 1 rheumatology assessment at a provincial arthritis center. Charts were available on 824 subjects, some of whom had been identified in the administrative database with > 1 diagnosis. Thus a total of 1136 diagnoses were available for verification against clinical records. Of the 824 subjects, 680 (83%) had their administrative database diagnoses confirmed on chart review. The majority of subjects who were "false-positive" for a given rheumatic disease on administrative data had a true diagnosis of a similar rheumatic disease. Most sensitivity estimates for specific administrative data-based case definitions were > 90%, although for SSc, the sensitivity was 80.5%. The specificity estimates were also > 90%, except for SLE, where the specificity was 72.5%. Conclusion. Although health administrative data may be a valid resource, there are potential problems regarding the specificity and sensitivity of case definitions, which should be kept in mind for future studies. The Journal of Rheumatology Copyright © 2011. All rights reserved.
[Ir(COD)Cl]2 as a catalyst precursor for the intramolecular hydroamination of unactivated alkenes with primary amines and secondary alkyl- or arylamines: A combined catalytic, mechanistic, and computational investigation
Hesp K.D.,Dalhousie University |
Tobisch S.,University of St. Andrews |
Stradiotto M.,Dalhousie University
Journal of the American Chemical Society | Year: 2010
The successful application of [Ir(COD)Cl]2 as a precatalyst for the intramolecular addition of primary as well as secondary alkyl- or arylamines to unactivated olefins at relatively low catalyst loading is reported (25 examples), along with a comprehensive experimental and computational investigation of the reaction mechanism. Catalyst optimization studies examining the cyclization of N-benzyl-2,2-diphenylpent-4-en-1-amine (1a) to the corresponding pyrrolidine (2a) revealed that for reactions conducted at 110°C neither the addition of salts (NnBu4Cl, LiOTf, AgBF4, or LiB(C6F5)4 • 2.5OEt2) nor phosphine coligands served to enhance the catalytic performance of [Ir(COD)Cl]2. In this regard, the rate of intramolecular hydroamination of 1a employing [Ir(COD)Cl]2/L2 (L2 = 2-(di-t-butylphosphino)biphenyl) catalyst mixtures exhibited an inverse-order dependence on L2 at 65°C, and a zero-order rate dependence on L2 at 110°C. However, the use of 5 mol % HNEt3Cl as a cocatalyst was required to promote the cyclization of primary aminoalkene substrates. Kinetic analysis of the hydroamination of 1a revealed that the reaction rate displays first order dependence on the concentration of Ir and inverse order dependence with respect to both substrate (1a) and product (2a) concentrations; a primary kinetic isotope effect (kH/kD = 3.4(3)) was also observed. Eyring and Arrhenius analyses for the cyclization of 1a to 2a afforded ΔH‡ = 20.9(3) kcal mol-1, ΔS‡ = -23.1(8) cal/K • mol, and Ea = 21.6(3) kcal mol-1, while a Hammett study of related arylaminoalkene substrates revealed that increased electron density at nitrogen encourages hydroamination (ρ = -2.4). Plausible mechanisms involving either activation of the olefin or the amine functionality have been scrutinized computationally. An energetically demanding oxidative addition of the amine N-H bond to the IrI center precludes the latter mechanism and instead activation of the olefin C=C bond prevails, with [Ir(COD)-Cl(substrate)] M1 representing the catalytically competent compound. Notably, such an olefin activation mechanism had not previously been documented for Ir-catalyzed alkene hydroamination. The operative mechanistic scenario involves: (1) smooth and reversible nucleophilic attack of the amine unit on the metalcoordinated C=C double bond to afford a zwitterionic intermediate; (2) Ir-C bond protonolysis via stepwise proton transfer from the ammonium unit to the metal and ensuing reductive elimination; and (3) final irreversible regeneration of M1 through associative cycloamine expulsion by new substrate. DFT unveils that reductive elimination involving a highly reactive and thus difficult to observe IrIII-hydrido intermediate, and passing through a highly organized transition state structure, is turnover limiting. The assessed effective barrier for cyclohydroamination of a prototypical secondary alkylamine agrees well with empirically determined Eyring parameters. © 2010 American Chemical Society.
Ahmed S.S.,Novartis |
Schur P.H.,Harvard University |
MacDonald N.E.,Dalhousie University |
Steinman L.,Stanford University
Journal of Autoimmunity | Year: 2014
The vaccine safety surveillance system effectively detected a very rare adverse event, narcolepsy, in subjects receiving AS03-adjuvanted A(H1N1) pandemic vaccine made using the European inactivation/purification protocol. The reports of increased cases of narcolepsy in non-vaccinated subjects infected with wild A(H1N1) pandemic influenza virus suggest a role for the viral antigen(s) in disease development. However, additional investigations are needed to better understand what factor(s) in wild influenza infection trigger(s) narcolepsy in susceptible hosts. An estimated 31 million doses of European AS03-adjuvanted A(H1N1) pandemic vaccine were used in more than 47 countries. The Canadian AS03-adjuvanted A(H1N1) pandemic vaccine was used with high coverage in Canada where an estimated 12 million doses were administered. As no similar narcolepsy association has been reported to date with the AS03-adjuvanted A(H1N1) pandemic vaccine made using the Canadian inactivation/purification protocol, this suggests that the AS03 adjuvant alone may not be responsible for the narcolepsy association. To date, no narcolepsy association has been reported with the MF59®-adjuvanted A(H1N1) pandemic vaccine. This review article provides a brief background on narcolepsy, outlines the different types of vaccine preparations including the ones for influenza, reviews the accumulated evidence for the safety of adjuvants, and explores the association between autoimmune diseases and natural infections. It concludes by assimilating the historical observations and recent clinical studies to formulate a feasible hypothesis on why vaccine-associated narcolepsy may not be solely linked to the AS03 adjuvant but more likely be linked to how the specific influenza antigen component of the European AS03-adjuvanted pandemic vaccine was prepared. Careful and long-term epidemiological studies of subjects who developed narcolepsy in association with AS03-adjuvanted A(H1N1) pandemic vaccine prepared with the European inactivation/purification protocol are needed. © 2014 The Authors.
Ng E.S.W.,Dalhousie University |
Law A.,Trent University
Canadian Journal on Aging | Year: 2014
How do older workers keep up and adapt to a changing workplace after age 55? In exploring that question, this study specifically examined how age-related changes affect workers, how older workers deal with a loss of resources, how they engage in life management, and why some are more successful than others. An in-depth analysis was undertaken using 32 semi-structured interviews conducted with workers aged 55 to 64. Findings revealed that older workers use various strategies to adapt to a change in resources, and that these strategies help them cope and maintain their functioning in the workplace. Because older workers require different types of employer support, this study offers an understanding of how employers can provide that support to encourage older workers to remain in the workforce longer. Several avenues for future research are suggested, including an exploration of the role played by internal sources of support. © 2013 Canadian Association on Gerontology.
Gero S.,Dalhousie University |
Gordon J.,University of St. Andrews |
Whitehead H.,Dalhousie University
Proceedings of the Royal Society B: Biological Sciences | Year: 2013
It is hypothesized that the primary function of permanent social relationships among female sperm whales (Physeter macrocephalus) is to provide allomothers for calves at the surface while mothers make foraging dives. In order to investigate how reciprocity of allocare within units of sperm whales facilitates group living, we constructed weighted social networks based on yearly matrices of associations (2005-2010) and correlated them across years, through changes in age and social role, to study changes in social relationships within seven sperm whale units. Pairs of association matrices from sequential years showed a greater positive correlation than expected by chance, but as the time lag increased, the correlation coefficients decreased. Over all units considered, calves had high values for all measured network statistics, while mothers had intermediate values for most of the measures, but high values for connectedness and affinity. Mothers showed sharp drops in strength and connectedness in the first year of their new calves' lives. These broad patterns appear to be consistent across units. Calves appeared to be significant nodes in the network of the social unit, and thus provide quantitative support for the theory in which communal care acts as the evolutionary force behind group formation in this species. © 2013 The Author(s) Published by the Royal Society. All rights reserved.
Murdoch-Eaton D.,University of Leeds |
Sargeant J.,Dalhousie University
Medical Education | Year: 2012
Context Although medical students receive varied feedback throughout their training programmes, research demonstrates that they frequently perceive it as insufficient. However, supervisors tend to perceive that it is adequate. Students' responses to, and use of, feedback are not clearly understood. The purposes of this study were to investigate how medical students recognise, respond to and utilise feedback, and to determine whether there are maturational differences in understandings of the role of feedback across academic years in medical school. Methods This was a mixed-methods study collecting qualitative (focus group and open-ended questionnaire items) and quantitative (questionnaire) data across the 5years of an undergraduate programme. Results A total of 68 students participated in 10 focus groups. The questionnaire response rate was 46% (564/1233). Data analysis investigated the students' perceptions of feedback and explored patterns of responses across the continuum of undergraduate medical school stages. Maturational differences among the year cohorts within the programme emerged in three general areas: (i) student perceptions of the purpose of feedback; (ii) student recognition of feedback, and (iii) student perceptions regarding the credibility of feedback providers. Conclusions Junior students generally perceived the receiving of feedback as a passive activity and preferred positive feedback that confirmed their progress and provided reassurance. More senior students viewed feedback as informing their specific learning needs and personal development. They valued immediate informal verbal feedback and feedback from peers and others, as well as that from senior teachers. Exploring students' progressive degrees of engagement with feedback and its relationship with self-esteem are subjects for further study. Discuss ideas arising from this article at '' © Blackwell Publishing Ltd 2012.
Chorney J.M.,Dalhousie University |
Tan E.T.,University of California at Irvine |
Kain Z.N.,University of New Haven
Anesthesiology | Year: 2013
Background: Many children experience significant distress before and after surgery. Previous studies indicate that healthcare providers' and parents' behaviors may influence children's outcomes. This study examines the influence of adults' behaviors on children's distress and coping in the postanesthesia care unit. Methods: Children aged 2-10 yr were videotaped during their postanesthesia care unit stay (n = 146). Adult and child behaviors were coded from video, including the onset, duration, and order of behaviors. Correlations were used to examine relations between behaviors, and time-window sequential statistical analyses were used to examine whether adult behaviors cued or followed children's distress and coping. Results: Sequential analysis demonstrated that children were significantly less likely to become distressed after an adult used empathy, distraction, or coping/assurance talk than they were at any other time. Conversely, if a child was already distressed, children were significantly more likely to remain distressed if an adult used reassurance or empathy than they were at any other time. Children were more likely to display coping behavior (e.g., distraction, nonprocedural talk) after an adult used this behavior. Conclusions: Adults can influence children's distress and coping in the postanesthesia care unit. Empathy, distraction, and assurance talk may be helpful in keeping a child from becoming distressed, and nonprocedural talk and distraction may cue children to cope. Reassurance should be avoided when a child is already distressed. © 2013, the American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins.
Oomen R.A.,Dalhousie University |
Gillett R.M.,Trent University |
Kyle C.J.,Trent University
Molecular Ecology Resources | Year: 2013
Characterization and population genetic analysis of multilocus genes, such as those found in the major histocompatibility complex (MHC) is challenging in nonmodel vertebrates. The traditional method of extensive cloning and Sanger sequencing is costly and time-intensive and indirect methods of assessment often underestimate total variation. Here, we explored the suitability of 454 pyrosequencing for characterizing multilocus genes for use in population genetic studies. We compared two sample tagging protocols and two bioinformatic procedures for 454 sequencing through characterization of a 185-bp fragment of MHC DRB exon 2 in wolverines (Gulo gulo) and further compared the results with those from cloning and Sanger sequencing. We found 10 putative DRB alleles in the 88 individuals screened with between two and four alleles per individual, suggesting amplification of a duplicated DRB gene. In addition to the putative alleles, all individuals possessed an easily identifiable pseudogene. In our system, sequence variants with a frequency below 6% in an individual sample were usually artefacts. However, we found that sample preparation and data processing procedures can greatly affect variant frequencies in addition to the complexity of the multilocus system. Therefore, we recommend determining a per-amplicon-variant frequency threshold for each unique system. The extremely deep coverage obtained in our study (approximately 5000×) coupled with the semi-quantitative nature of pyrosequencing enabled us to assign all putative alleles to the two DRB loci, which is generally not possible using traditional methods. Our method of obtaining locus-specific MHC genotypes will enhance population genetic analyses and studies on disease susceptibility in nonmodel wildlife species. © 2012 Blackwell Publishing Ltd.
Clegg A.,University of Leeds |
Young J.,University of Leeds |
Iliffe S.,University College London |
Rikkert M.O.,Raboud University Medical Center |
Rockwood K.,Dalhousie University
The Lancet | Year: 2013
Frailty is the most problematic expression of population ageing. It is a state of vulnerability to poor resolution of homoeostasis after a stressor event and is a consequence of cumulative decline in many physiological systems during a lifetime. This cumulative decline depletes homoeostatic reserves until minor stressor events trigger disproportionate changes in health status. In landmark studies, investigators have developed valid models of frailty and these models have allowed epidemiological investigations that show the association between frailty and adverse health outcomes. We need to develop more efficient methods to detect frailty and measure its severity in routine clinical practice, especially methods that are useful for primary care. Such progress would greatly inform the appropriate selection of elderly people for invasive procedures or drug treatments and would be the basis for a shift in the care of frail elderly people towards more appropriate goal-directed care.
Connell T.,McGill University |
Robar J.L.,Dalhousie University
Medical Physics | Year: 2010
Purpose: Recently, several authors have shown contrast improvements in megavoltage portal imaging and cone-beam computed tomography using low atomic number (Z) targets. This work compliments previous studies by investigating the effects of varying different beam production parameters including target atomic number, target thickness, and incident electron energy on spatial resolution. Methods: Target materials of beryllium, aluminum, and tungsten were investigated over a range of thicknesses between 10% and 100% of the continuous slowing down approximation range of electrons. Incident electron kinetic energies of 4.5 and 7.0 MeV were used, in conjunction with custom targets installed above the carousel of a modern radiotherapy linear accelerator. Monte Carlo simulations of the accelerator were constructed and compared to the experimental results. Results: The results showed that thinner targets, as well higher incident electron energies, generally produce more favorable modulation transfer function (MTF) curves. Due to an MTF dependence of the detector system on the photon energy, the experimental results showed that low- Z targets produced superior MTF curves. Simulations showed 14.5% and 21.5% increases in f50 for the 7.0 and 4.5 MeV targets (Al; 60% R%CSDA), respectively, when moved from the carousel to the location of the clinical target. f50 values for the custom targets were compared to the clinical 6 MV beam and were found to be between 10.4% lower (4.5 MeV/W) and 15.5% higher (7.0 MeV/Be). Conclusions: Integration of low- Z external targets into the treatment head of a medical linear was achieved with only minor modifications. It was shown that reasonably high resolution images on par or better than those acquired with the clinical 6 MV beam can be achieved using external low- Z targets. © 2010 American Association of Physicists in Medicine.
News Article | September 15, 2016
When the sixth extinction comes, as far as the oceans are concerned, larger sea creatures are more likely to die before their smaller counterparts. Why? Human influence. In a recent study, a group of scientists led by Stanford University paleobiologist Jonathan Payne found that because of various human activities such as damaging habitats, spreading invasive species and diseases, hunting, poaching and driving global temperatures up, we could soon be on the cusp of an extinction event, and when it comes, larger sea creatures will be the first to go. This sixth extinction event will be the first caused by humans, as opposed to the past five mass extinction events, which were all caused by natural events. How did they reach this conclusion? By checking out which marine animal groups are currently most at risk. The study, published in Science, details how the team identified which marine animals are currently at risk of extinction by checking the the International Union for the Conservation of Nature's list of threatened species. From there, they cross-referenced these animals with fossil records of sea creatures that died out in previous extinction events. The result? Contrary to extinction events in the past, sea creatures that were most at risk also happened to be on the larger side. Specifically, a tenfold increase in body mass corresponds to a 13-fold increase in the threat of extinction. "We've found that extinction threat in the modern oceans is very strongly associated with larger body size," Payne said in a news release. "This is most likely due to people targeting larger species for consumption first." Simply put, this means that whales are more likely to die off than crabs. And unfortunately, whales dying off would have dire consequences for local ecosystems as a whole. For example, in the whales' absence, the populations of other creatures that were once kept in check would rise to new levels, potentially having adverse effects in the area. Similarly, whales are known to keep nutrients moving through their marine environments as they feed and excrete waste. This isn't the first time that a study has found a correlation between hunting by humans and the fate of various sea animals. In 2014, researchers found that some animals evolved to become smaller so that they would be deemed as a less desirable target for hunters. In the meantime, while the revelation of larger sea creatures being more likely to die off first is certainly a scary prospect, there's still some hope — so long as we act. "We're not screwed," says Boris Worm, a marine conservation biologist at Dalhousie University. By discovering that human actions are driving larger sea creatures to extinction, we now can work on protecting them by rethinking fishing methods and regulations. "We're really at a point where we need to make a decision," Worm says, about whether we allow the destruction continue or reverse it. "And we have the power to reverse it." © 2017 Tech Times, All rights reserved. Do not reproduce without permission.
News Article | December 11, 2015
The new movie In the Heart of the Sea follows the crew of the whaling ship Essex on their doomed 1820 voyage that inspired the Herman Melville novel Moby Dick. In the remote South Pacific, the Essex was destroyed in an encounter with a sperm whale, and the 20-man crew had to pile into three small boats to escape. Over the following weeks, the men struggled to survive and resorted to cannibalizing those who perished. The movie, which has received tepid reviews, suffers from a major flaw: It expects the audience to root for a crew that set out to kill whales. And in a time when one poached lion can provoke a huge outpouring of love for the animal and anger toward the shooter, that may be too much to ask. Especially given the horrific scope of whaling. Humans have been killing whales for thousands of years, but it wasn’t until the 17th century, when commercial whaling began, that the killing began to ramp up to numbers big enough to threaten species. Sperm whales became prime targets, prized for the spermaceti, a liquid wax found inside their heads, and the waxy ambergris produced as a by-product of digestion. And then there was all the whale oil, rendered from blubber, that was used to light lamps and make margarine and soap. Prior to the 20th century, commercial whaling was a difficult and dangerous business, as the Essex incident illustrates. When sailors spotted a whale from a ship, they would climb into small whaleboats to pursue their prey. They would harpoon the animal, which would then tug the whaleboat (hopefully not too far from the main ship) until it became too tired and stopped swimming. Then, a sailor would make the final kill, striking the animal in the heart or lungs. If the whalers were lucky, the huge animal would be killed before they were. Given the danger of hunting large creatures in the open ocean, it’s difficult to imagine that this hunting method would make much of a dent in whale populations. But it did. Hal Whitehead, a whale biologist at Dalhousie University in Halifax, Nova Scotia, estimated that by 1880, whalers had managed to reduce the sperm whale population by 29 percent, from 1,110,000 whales before commercial whaling to about 788,000 animals. But that’s not where the sperm whale’s story ends. Whaling slowed down in the late 19th century, as petroleum replaced whale oil and sailing ships disappeared. A couple of major wars also intervened. But then whaling picked up again, and this time, modern ships and exploding harpoons meant that hunting whales was now fairly easy and safe. With many baleen species having been driven to low numbers by the previous era of whaling, these new whalers turned to the sperm whale. The earlier generation of whalers managed to kill some 5,000 sperm whales per year at most; in the 1960s, they killed as many as 25,000 annually. (And the situation might have been even worse — both the Soviet Union and Japan falsified whaling records during the height of 20th-century hunting.) The commercial killing didn’t stop until the International Whaling Commission ended whaling in 1985. Despite the ban, Japan continues to hunt whales, including sperm whales, purportedly for scientific purposes, though the meat is sold in markets. Whitehead has estimated that by 1999, a decade after hunting ended, there were only 360,000 sperm whales, about a third of what had existed during pre-commercial whaling. Whether that number has increased since then isn’t known, but the International Union for the Conservation of Nature considers the animals to be vulnerable, one step shy of endangered. Given this history, I find it difficult to feel sympathy for a bunch of whalers on the big screen. So if I do decide to go see In the Heart of the Sea, I’m rooting for the whale.
News Article | June 10, 2014
A new kind of solar-sensitive nanoparticles could create flexible and efficient solar cells, possible making the technology available to consumers on a huge scale, Canadian researchers say. The newly designed nanoparticle, dubbed a "colloidal quantum dot," makes use of two kinds of semiconductors, of which one has an unfortunate tendency to break down when it's exposed to air, losing its electrons and its ability to generate electricity, they said. University of Toronto researchers say they've solved that dilemma by creating a nanoparticle "dot" that does will bind with oxygen during exposure to air. Such quantum dots, being much more stable, could lead to solar cells that are more flexible and cheaper to manufacture to use in a number of different applications, they said. "Colloidal quantum dots (CQDs) offer promise in flexible electronics, light sensing and energy conversion," the researchers wrote in the journal Nature Materials. By boosting light absorption, they could also be used in other technical applications and optoelectrical devices combing electricity and light such as infrared lasers, gas sensors, or infrared light-emitting diodes, they said. They could also lead to advances in "weather satellites, remote controllers, satellite communication, or pollution detectors," they wrote. "This is a material innovation, that's the first part, and with this new material we can build new device structures," post-doctoral researcher Zhijun Ning said. Once the technology is refined, the researchers said, the quantum dots could even be mixed with inks for printed surfaces, into paint, or applied to flexible substrates such as roof shingles to create solar power for millions around the world at an affordable cost. The new quantum dot material has achieved conversion efficiently for solar power of up to eight percent, the researchers said, among the best results from similar technology reported to date. "The field of colloidal quantum dot photovoltaics requires continued improvement in absolute performance, or power conversion efficiency," says Toronto researcher Ted Sargent, in the university's Edward S. Rogers Sr. Department of Electrical & Compute Engineering. "The field has moved fast, and keeps moving fast, but we need to work toward bringing performance to commercially compelling levels." Participating in the Toronto research were scientists from Dalhousie University in Nova Scotia, King Abdulla University of Science and Technology in Saudi Arabia and Huazhong University of Science and Technology in China.
Viesca R.C.,Tufts University |
Viesca R.C.,Dalhousie University |
Garagash D.I.,Dalhousie University
Nature Geoscience | Year: 2015
Laboratory simulations of earthquakes show