The University of Ottawa is a bilingual public research university in Ottawa, Ontario, Canada. The main campus is located on 42.5 hectares in the residential neighbourhood of Sandy Hill, adjacent to Ottawa's Rideau Canal. The university offers a wide variety of academic programs, administered by ten faculties. It is a member of the U15, a group of research-intensive universities in Canada.The University of Ottawa was first established as the College of Bytown in 1848 by the first bishop of the Catholic Archdiocese of Ottawa, Joseph-Bruno Guigues. Placed under the direction of the Oblates of Mary Immaculate, it was renamed the College of Ottawa in 1861 and received university status five years later through royal charter. On 5 February 1889, the university was granted a pontifical charter by Pope Leo XIII, elevating the institution to a pontifical university. The University was reorganized on 1 July 1965 as a corporation, independent from any outside body or religious organization. As a result, the civil and pontifical charters were kept by the newly created Saint Paul University, federated with the university. The remaining civil faculties were retained by the reorganized university.The university is co-educational and enrolls over 40,000 students, over 35,000 undergraduate and over 6,000 post-graduate students. The university has more than 185,000 alumni. The university's athletic teams are known as the Gee-Gees and are members of Canadian Interuniversity Sport. Wikipedia.
Mohammadian M.,University of Ottawa
International Journal for Numerical Methods in Fluids | Year: 2012
A class of axisymmetric horizontal flows dominated by strong heat or mass sources are considered here, which systematically arise in multiscale atmospheric and oceanic flows in various spatiotemporal scales such as hurricane embryos. Various linear and nonlinear analytical solutions are proposed, and several examples are given to illustrate them. On the basis of the proposed exact solutions, stability of the flow under various conditions is examined. The proposed exact solutions serve as benchmarks for validation of numerical models. A Chebyshev pseudospectral model is also developed for these flows. The numerical results are compared with the developed analytical solutions as well as a high-resolution numerical solution, which showed an excellent performance of the numerical model in terms of numerical diffusion and oscillation. The numerical method is also efficient because expensive calculations such as LU decomposition are only needed once, at the beginning of calculations. The model could be used in studying small-scale and multiple-scale phenomena such as hot towers and hurricane embryos, which are the subject of future studies. © 2011 John Wiley & Sons, Ltd.
Beamish E.,University of Ottawa
Journal of visualized experiments : JoVE | Year: 2013
Solid-state nanopores have emerged as a versatile tool for the characterization of single biomolecules such as nucleic acids and proteins. However, the creation of a nanopore in a thin insulating membrane remains challenging. Fabrication methods involving specialized focused electron beam systems can produce well-defined nanopores, but yield of reliable and low-noise nanopores in commercially available membranes remains low and size control is nontrivial. Here, the application of high electric fields to fine-tune the size of the nanopore while ensuring optimal low-noise performance is demonstrated. These short pulses of high electric field are used to produce a pristine electrical signal and allow for enlarging of nanopores with subnanometer precision upon prolonged exposure. This method is performed in situ in an aqueous environment using standard laboratory equipment, improving the yield and reproducibility of solid-state nanopore fabrication.
MacVicar B.J.,University of Waterloo |
Rennie C.D.,University of Ottawa
Water Resources Research | Year: 2012
Multiple hypotheses have been advanced to explain the occurrence of pools in gravel bed rivers. These hypotheses were developed without a hydrodynamic model of how open channel flow is affected by pools, and it is not clear why and when the flow phenomena they describe might occur. Laboratory experiments are warranted to improve our understanding of how a gradual convective deceleration and acceleration of the flow, without flow separation, redistributes flow and turbulence in an open channel. Experiments are conducted in a 1.5 m wide flume with a 0.25 m deep, 7.29 m long straight pool, entry and exit slopes of 5, vertical side walls, and gravel sediment (D 50 = 9.9 mm). Three-dimensional velocity components are recorded at 50 Hz using Nortek Vectrinos. Velocity and Reynolds stress profiles in the channel centerline agree with previous results in nonuniform flow and include increased Reynolds stress during deceleration and high velocity near the bed during acceleration. Lateral flow convergence occurs where depth is increasing, which demonstrates that convergence is induced during flow deceleration and does not require a lateral flow constriction. Turbulence during deceleration is characterized by sweeps angled toward the sidewall of the channel, an effect that could lead to the formation of a nonuniform pool depth through lateral gradients in the deposition of mobile sediment. A conceptual model of pool hydrodynamics is proposed that includes increased turbulence, near-bed acceleration, and lateral flow convergence as linked aspects of convective deceleration and acceleration due to depth changes in the pool. Copyright © 2012 by the American Geophysical Union.
L'Heureux I.,University of Ottawa
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences | Year: 2013
Chemical oscillating patterns are ubiquitous in geochemical systems. Although many such patterns result from systematic variations in the external environmental conditions, it is recognized that some patterns are due to intrinsic self-organized processes in a non-equilibrium nonlinear system with positive feedback. In rocks andminerals, periodic precipitation (Liesegang bands) and oscillatory zoning constitute good examples of patterns that can be explained using concepts from nonlinear dynamics. Generally, as the system parameters exceed some threshold values, the steady (time-independent) state characterizing the system loses its stability. The system then evolves towards other time-dependent solutions ('attractors') that may have an oscillatory behaviour or a complex chaotic one. In this review, we describe many of these pattern types taken from a variety of geological environments: eruptive, sedimentary, hydrothermal or metamorphic. One particular example (periodic precipitation of pyrite bands in an evolving sapropel sediment) is presented here for the first time. This will help in convincing the reader that the tools of nonlinear dynamics may be useful to understand the history of our planet. © 2013 The Author(s) Published by the Royal Society. All rights reserved.
Kretz R.,University of Ottawa
Journal of Metamorphic Geology | Year: 2014
Experimental data on diffusion in olivine Mg,Fe2SiO4, are used to define certain terms - diffusion coefficient, jump frequency, characteristic distance, random walk - that are useful in a discussion of atom displacements under natural conditions. Examples of atom displacements in two metamorphic terranes of the Canadian Precambrian Shield are then examined, as follows. (i) In a high-grade metamorphic terrane in the Mid-Proterozoic Grenville Province (Otter Lake Area), Mg concentration gradients about dolomite microcrystals in calcite and Na gradients about albite microcrystals in K-feldspar are viewed as stranded Mg-Ca and Na-K interdiffusion gradients, formed by exsolution during slow cooling from ~700 to ~400 °C. (ii) In the Archean Slave Province (Yellowknife area), the crystallization of sillimanite, near andalusite but within crystals of quartz, possibly occurred by coupled Al-Si and oxygen-vacancy interdiffusion in quartz at ~550 °C. And the crystallization of garnet from chlorite occurred by the two-way crystal-boundary diffusion of several kinds of atoms across distances ranging to 3 mm. (iii) In the Otter Lake area, the crystallization of orthopyroxene-hornblende-spinel reaction zones at boundaries between crystals of olivine and plagioclase in metagabbro, evidently occurred by the mechanism of interstitial diffusion, that transported Mg, Fe, Mn and O atoms across the reaction zone from olivine to the plagioclase-(hornblende+spinel) boundary, and Si, Al, Ca and Na atoms from plagioclase to the olivine-orthopyroxene boundary, accompanied by NaSi-CaAl interdiffusion in plagioclase, and the addition of hydrogen and minor Ti, Zn, F, Cl and K from beyond the reaction zone. Also, centimetric reaction zones, with abundant biotite and plagioclase, at boundaries between K-feldspar gneiss and deformed amphibolite dykes, evidently formed by the reaction, strained hornblende (in amphibolite) + K-feldspar (in gneiss)→biotite (in amphibolite) + plagioclase (in gneiss), with crystal-boundary diffusion of (Na + Ca) atoms and of K atoms across the reaction zone. Copyright © 2014 John Wiley & Sons Ltd 329 December 2014 10.1111/jmg.12104 Original Article Original Articles © 2014 John Wiley & Sons Ltd.
Van Der Jagt R.,University of Ottawa
Expert Review of Hematology | Year: 2013
Bendamustine is an agent with mostly alkylating properties, which acts on dividing cells through multiple pathways. As an agent with little cross-resistance with other chemotherapeutic agents, bendamustine has received approval for second-line use in relapsed/refractory indolent lymphomas. A growing body of data showing good efficacy and acceptable tolerability of bendamustine in first-line use has led to recognition that this agent has an important role in this setting. This article outlines the pharmacology and clinical studies supporting the use of bendamustine and discusses the role of this agent in the first-and second-line treatment of indolent lymphomas. © 2013 Informa UK Ltd.
Poulain A.J.,University of Ottawa |
Barkay T.,Rutgers University
Science | Year: 2013
Identification of two genes involved in mercury methylation may help to develop biomarkers to track and manage mercury contamination in the environment.
Taylor J.,Fox Chase Cancer Center |
Pelchat M.,University of Ottawa
Future Microbiology | Year: 2010
This article addresses some of the questions relating to how hepatitis virus (HDV), an agent so far unique in the animal world, might have arisen. HDV was discovered in patients infected with hepatitis B virus (HBV). It generally makes HBV infections more damaging to the liver. It is a subviral satellite agent that depends upon HBV envelope proteins for its assembly and ability to infect new cells. In other aspects of replication, HDV is both independent of and very different from HBV. In addition, the small single-stranded circular RNA genome of HDV, and its mechanism of replication, demonstrate an increasing number of similarities to the viroids-a large family of helper-independent subviral agents that cause pathogenesis in plants. © 2010 Future Medicine Ltd.
Muckle W.,University of Ottawa
Cochrane database of systematic reviews (Online) | Year: 2012
Managed alcohol programmes (MAP) are a harm reduction strategy used to minimise the personal harm and adverse societal effects that alcohol dependence can lead to by providing an alternative to zero-tolerance approaches that incorporate drinking goals (abstinence or moderation) that are compatible with the needs of the individual, and promoting access to services by offering low-threshold alternatives. This enables clients to gain access to services despite continued alcohol consumption and works to help the patient understand the risks involved in their behaviour and make decisions about their own treatment goals. To assess the effectiveness of MAP treatment regimens (serving limited quantities of alcohol daily to alcoholics) on their own or as compared to moderate drinking (self-controlled drinking), screening and brief intervention using a harm reduction approach, traditional abstinence-based interventions (12 step programmes) and no intervention. We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, CINAHL and PsycINFO up to March 2012. This search was expanded by handsearching of high-yield journals and conference proceedings that had not already been handsearched on behalf of The Cochrane Collaboration, searching reference lists of all papers and relevant reviews identified, references to ongoing and recently completed clinical trials in the National Research Register and IFPMA Clinical Trials Database (which contains ClinicalTrials.gov, Centerwatch, Current Controlled Trials and ClinicalStudyResults.gov, and Osservatorio Nazionale sulla Sperimentazione Clinica dei Medicinali). Trials registers, grey literature and reference lists were also searched. Individuals, organisations and experts in the field were contacted. Randomised control trials (RCT), controlled clinical trials (CCT), interrupted time series (ITS) studies, and control before and after (CBA) studies involving vulnerable people aged 18 years or older who were at high risk for alcohol abuse attending MAP, defined as a structured programme that provided clients with controlled amounts of alcohol on a daily schedule, comparing no treatment, moderate drinking, brief intervention or 12-step variants. All study citations were collated into a single database. Two review author independently screened titles and abstracts and selected references potentially relevant to the review. Differences between selection lists were resolved by discussion. Two review authors independently evaluated whether studies should be included or excluded according to the eligibility criteria. In the event of a disagreement, a third author was consulted. No studies were included in the review. This systematic review was intended to assess the effectiveness of a brief MAP on the reduction of incidence of harmful behaviour; however, no evidence was available to make this comparison; 22 articles were considered possibly relevant and all were excluded. Most articles were excluded because they failed to compare or consider managed alcohol as the experimental or control intervention, as well as one study (Baker 2010), which was also excluded because study participants were under 18 years of age. No study reviewed offered an intervention that was compared with managed alcohol or considered it as the intervention of interest, providing insufficient evidence to address the objectives of the review.
McPherson R.,University of Ottawa
Canadian Journal of Cardiology | Year: 2013
Genome-wide association studies (GWASs) for coronary artery disease (CAD) have identified more than 30 variants robustly associated with CAD risk. The majority are not associated with conventional risk factors but highlight novel pathways, including cellular proliferation. Although some risk variants are nonsynonymous coding variants resulting in an amino acid change in the encoded protein, the majority are in noncoding regions of the genome and may encompass multiple signals of variable effect. The use of genetic data for development of new therapies requires the identification of causative genetic variants and elucidation of the molecular mechanisms by which they predispose to CAD. The computational and laboratory approaches for the interpretation of GWAS data are discussed with a particular focus on noncoding variants, including the study of regulatory elements, the evaluation of nonsynonymous coding variants, and expression quantitative trait locus analysis for the integration of GWAS data with genome-wide messenger RNA expression data. © 2013 Canadian Cardiovascular Society.
Pipe A.L.,University of Ottawa
Clinical Journal of Sport Medicine | Year: 2011
International travel is a frequent occurrence in the life of the elite athlete; such travel can pose challenges to the sport medicine practitioner. Travel is also the reality of many recreational level or subelite athletes as opportunities for international competition and training proliferate. An appreciation of the range of responsibilities associated with the preparation for and the strategies to facilitate such travel is essential for any physician charged with the care of athletes and teams. An appreciation of (1) the medical and public health challenges associated with competition in a particular setting; (2) the requirements for vaccination and immunization; (3) the strategies for the management of jet lag and climatic or environmental extremes; (4) the range of supplies and equipment necessary for travel to certain locales; (5) the need to ensure the availability of ample familiar and nutritious foods; (6) the potential need for specialty care in strange settings; (7) the management of common travel-associated illness; and (8) the challenges associated with the evacuation of an injured athlete are fundamental to the successful management of international travel involving athletes and teams. The adoption of a methodical approach to pre-trip planning can ensure an enhanced travel experience, illness-free training and competition, and facilitate optimal performance. Copyright © 2011 by Lippincott Williams & Wilkins.
Kirpalani H.,Childrens Hospital of Philadelphia |
Kirpalani H.,McMaster University |
Millar D.,Royal Maternity Hospital |
Lemyre B.,University of Ottawa |
And 3 more authors.
New England Journal of Medicine | Year: 2013
BACKGROUND: To reduce the risk of bronchopulmonary dysplasia in extremely-low-birth-weight infants, clinicians attempt to minimize the use of endotracheal intubation by the early introduction of less invasive forms of positive airway pressure. METHODS: We randomly assigned 1009 infants with a birth weight of less than 1000 g and a gestational age of less than 30 weeks to one of two forms of noninvasive respiratory support - nasal intermittent positive-pressure ventilation (IPPV) or nasal continuous positive airway pressure (CPAP) - at the time of the first use of noninvasive respiratory support during the first 28 days of life. The primary outcome was death before 36 weeks of postmenstrual age or survival with bronchopulmonary dysplasia. RESULTS: Of the 497 infants assigned to nasal IPPV for whom adequate data were available, 191 died or survived with bronchopulmonary dysplasia (38.4%), as compared with 180 of 490 infants assigned to nasal CPAP (36.7%) (adjusted odds ratio, 1.09; 95% confidence interval, 0.83 to 1.43; P = 0.56). The frequencies of air leaks and necrotizing enterocolitis, the duration of respiratory support, and the time to full feedings did not differ significantly between treatment groups. CONCLUSIONS: Among extremely-low-birth-weight infants, the rate of survival to 36 weeks of post-menstrual age without bronchopulmonary dysplasia did not differ significantly after noninvasive respiratory support with nasal IPPV as compared with nasal CPAP. Copyright © 2013 Massachusetts Medical Society.
Dolgaleva K.,Kings College |
Boyd R.W.,University of Ottawa |
Boyd R.W.,University of Rochester
Advances in Optics and Photonics | Year: 2012
It is well known that the optical response of a medium depends on the local field acting on an individual emitter rather than on the macroscopic average field in the medium. The local field depends very sensitively on the microcopic environment in an optical medium. It is thus possible to achieve a significant control over the local field by intermixing homogeneous materials on a nanoscale to produce composite optical materials. A combination of local-field effects and nanostructuring provides new degrees of freedom for manipulating the optical properties of photonic materials. Especially interesting opportunities open up in the nonlinear optical regime where the material response depends on the local-field correction as a power law. The goal of this review is to present a conceptual overview of the influence of local-field effects on the optical properties of photonic materials, both homogeneous and composite. We also give a summary of recent achievements in controlling the optical properties by local-field effects and nanostructuring. © 2010 Optical Society of America.
Wong A.,University of Ottawa
Evolution | Year: 2010
Post-copulatory sexual selection has been proposed to drive the rapid evolution of reproductive proteins, and, more recently, to increase genome-wide mutation rates. Comparisons of rates of molecular evolution between lineages with different levels of female multiple mating represent a promising, but under-utilized, approach for testing the effects of sperm competition on sequence evolution. Here, I use comparisons between primate species with divergent mating systems to examine the effects of sperm competition on reproductive protein evolution, as well as on sex-averaged mutation rates. Rates of nonsynonymous substitution are higher for testis-specific genes along the chimpanzee lineage in comparison to the human lineage, consistent with expectations. However, the data reported here do not allow firm conclusions concerning the effects of mating system on genome-wide mutation rates, with different results obtained from different species pairs. Ultimately, comparative studies encompassing a range of mating systems and other life history traits will be required to make broad generalizations concerning the genomic effects of sperm competition. © 2010 The Author(s). Journal compilation © 2010 The Society for the Study of Evolution.
Levy P.,University of Ottawa
Information Sciences | Year: 2010
The IEML research program promotes a radical innovation in the notation and processing of semantics. IEML (Information Economy MetaLanguage) is a regular language that provides new methods for semantic interoperability, semantic navigation, collective categorization and self-referential collective intelligence. This research program is compatible with the major standards of the Web of data and is in tune with the current trends in social computing. The paper explains the philosophical relevance of this new language, expounds its syntactic and semantic structures and ponders its possible implications for the growth of collective intelligence in cyberspace. © 2009 Elsevier Inc. All rights reserved.
Al-Mohaissen M.A.,University of Ottawa
Current cardiology reports | Year: 2013
Tricuspid regurgitation due to permanent pacemaker/defibrillator lead implantation (LITR) has been described more than 3 decades ago, but has come into attention recently due to the dramatic increase in the use of these devices. This entity has not been well defined and its impact on the patient and the health care system is largely unknown. This complication can have important implications. First, the presence and severity of tricuspid regurgitation in general is associated with reduced patient survival, and in the severe cases may require corrective surgery. Second, with the increasing age of the population and the expanding indications of these devices, one expects to encounter many more cases of LITR in the future. Third, this is an iatrogenic complication and therefore potentially preventable. This review discusses the prevalence, mechanisms, and risk factors of LITR as well as the management and potential strategies to prevent its occurrence.
Mielke J.,University of Ottawa
Journal of the Acoustical Society of America | Year: 2015
This is an acoustic and articulatory study of Canadian French rhotic vowels, i.e., mid front rounded vowels /ø œ œ/ produced with a rhotic perceptual quality, much like English, leading heureux, commun, and docteur to sound like. Ultrasound, video, and acoustic data from 23 Canadian French speakers are analyzed using several measures of mid-sagittal tongue contours, showing that the low F3 of rhotic vowels is achieved using bunched and retroflex tongue postures and that the articulatory-acoustic mapping of F1 and F2 are rearranged in systems with rhotic vowels. A subset of speakers' French vowels are compared with their English, revealing that the French vowels are consistently less extreme in low F3 and its articulatory correlates, even for the most rhotic speakers. Polar coordinates are proposed as a replacement for Cartesian coordinates in calculating smoothing spline comparisons of mid-sagittal tongue shapes, because they enable comparisons to be roughly perpendicular to the tongue surface, which is critical for comparisons involving tongue root position but appropriate for all comparisons involving mid-sagittal tongue contours. © 2015 Acoustical Society of America.
Regnault-Roger C.,University of Pau and Pays de lAdour |
Vincent C.,Agriculture and Agri Food Canada |
Arnason J.T.,University of Ottawa
Annual Review of Entomology | Year: 2012
In recent years, the use of essential oils (EOs) derived from aromatic plants as low-risk insecticides has increased considerably owing to their popularity with organic growers and environmentally conscious consumers. EOs are easily produced by steam distillation of plant material and contain many volatile, low-molecular-weight terpenes and phenolics. The major plant families from which EOs are extracted include Myrtaceae, Lauraceae, Lamiaceae, and Asteraceae. EOs have repellent, insecticidal, and growth-reducing effects on a variety of insects. They have been used effectively to control preharvest and postharvest phytophagous insects and as insect repellents for biting flies and for home and garden insects. The compounds exert their activities on insects through neurotoxic effects involving several mechanisms, notably through GABA, octopamine synapses, and the inhibition of acetylcholinesterase. With a few exceptions, their mammalian toxicity is low and environmental persistence is short. Registration has been the main bottleneck in putting new products on the market, but more EOs have been approved for use in the United States than elsewhere owing to reduced-risk processes for these materials. © 2012 by Annual Reviews. All rights reserved.
Bryce D.L.,University of Ottawa
Dalton Transactions | Year: 2010
Calcium is an important component of materials, metalloproteins, minerals, glasses, and small inorganic and organic complexes. However, NMR spectroscopy of the quadrupolar 43Ca nuclide remains difficult primarily due to its low natural abundance and low resonance frequency. In this Perspective, experimental challenges and recent successes in the field are highlighted, with a focus on solid-state 43Ca NMR spectroscopy. Solution 43Ca NMR studies of calcium-binding biomolecules are also presented. The structural insights afforded from quadrupolar and chemical shift parameters are examined. For example: isotropic chemical shifts have been shown to correlate with the mean Ca-O distance and also with calcium coordination number; quadrupolar coupling constants and chemical shift tensor spans have been shown to be useful probes of polymorphism; and, distance measurements involving 43Ca have been recently demonstrated. Lastly, challenges and opportunities for the future are considered. © 2010 The Royal Society of Chemistry.
Julian L.M.,University of Ottawa
Cell Death and Differentiation | Year: 2015
Cell cycle proteins are important regulators of diverse cell fate decisions, and in this capacity have pivotal roles in neurogenesis and brain development. The mechanisms by which cell cycle regulation is integrated with cell fate control in the brain and other tissues are poorly understood, and an outstanding question is whether the cell cycle machinery regulates fate decisions directly or instead as a secondary consequence of proliferative control. Identification of the genes targeted by E2 promoter binding factor (E2f) transcription factors, effectors of the pRb/E2f cell cycle pathway, will provide essential insights into these mechanisms. We identified the promoter regions bound by three neurogenic E2f factors in neural precursor cells in a genome-wide manner. Through bioinformatic analyses and integration of published genomic data sets we uncovered hundreds of transcriptionally active E2f-bound promoters corresponding to genes that control cell fate processes, including key transcriptional regulators and members of the Notch, fibroblast growth factor, Wnt and Tgf-β signaling pathways. We also demonstrate a striking enrichment of the CCCTC binding factor transcription factor (Ctcf) at E2f3-bound nervous system-related genes, suggesting a potential regulatory co-factor for E2f3 in controlling differentiation. Finally, we provide the first demonstration of extensive tissue specificity among E2f target genes in mammalian cells, whereby E2f3 promoter binding is well conserved between neural and muscle precursors at genes associated with cell cycle processes, but is tissue-specific at differentiation-associated genes. Our findings implicate the cell cycle pathway as a widespread regulator of cell fate genes, and suggest that E2f3 proteins control cell type-specific differentiation programs by regulating unique sets of target genes. This work significantly enhances our understanding of how the cell cycle machinery impacts cell fate and differentiation, and will importantly drive further discovery regarding the mechanisms of cell fate control and transcriptional regulation in the brain, as well as in other tissues.Cell Death and Differentiation advance online publication, 24 April 2015; doi:10.1038/cdd.2015.36. © 2015 Macmillan Publishers Limited
Ros F.J.,University of Murcia |
Ruiz P.M.,University of Murcia |
Stojmenovic I.,University of Ottawa
IEEE Transactions on Mobile Computing | Year: 2012
We propose a broadcast algorithm suitable for a wide range of vehicular scenarios, which only employs local information acquired via periodic beacon messages, containing acknowledgments of the circulated broadcast messages. Each vehicle decides whether it belongs to a connected dominating set (CDS). Vehicles in the CDS use a shorter waiting period before possible retransmission. At time-out expiration, a vehicle retransmits if it is aware of at least one neighbor in need of the message. To address intermittent connectivity and appearance of new neighbors, the evaluation timer can be restarted. Our algorithm resolves propagation at road intersections without any need to even recognize intersections. It is inherently adaptable to different mobility regimes, without the need to classify network or vehicle speeds. In a thorough simulation-based performance evaluation, our algorithm is shown to provide higher reliability and message efficiency than existing approaches for nonsafety applications. © 2006 IEEE.
Shapiro J.H.,Massachusetts Institute of Technology |
Boyd R.W.,University of Rochester |
Boyd R.W.,University of Ottawa
Quantum Information Processing | Year: 2012
Ghost images are obtained by correlating the output of a single-pixel (bucket) photodetector-which collects light that has been transmitted through or reflected from an object-with the output from a high spatial-resolution scanning photodetector or photodetector array whose illumination has not interacted with that object. The term "ghost image" is apt because neither detector's output alone can yield an image: the bucket detector has no spatial resolution, while the high spatial-resolution detector has not viewed the object. The first ghost imaging experiment relied on the entangled signal and idler outputs from a spontaneous parametric downconverter, and hence the image was interpreted as a quantum phenomenon. Subsequent theory and experiments showed, however, that classical correlations can be used to form ghost images. For example, ghost images can be formed with pseudothermal light, for which quantum mechanics is not required to characterize its photodetection statistics. This paper presents an overview of the physics of ghost imaging. It clarifies and unites two disparate interpretations of pseudothermal ghost imaging-two-photon interference and classical intensity-fluctuation correlations-that had previously been thought to beconflicting. It also reviews recent work on ghost imaging in reflection, ghost imaging through atmospheric turbulence, computational ghost imaging, and two-color ghost imaging. © Springer Science+Business Media, LLC 2012.
French H.,University of Ottawa |
Shur Y.,University of Alaska Fairbanks
Earth-Science Reviews | Year: 2010
Cryostratigraphy adopts concepts from both Russian geocryology and modern sedimentology. Structures formed by the amount and distribution of ice within sediment and rock are termed cryostructures. Typically, layered cryostructures are indicative of syngenetic permafrost while reticulate and irregular cryostructures are indicative of epigenetic permafrost. 'Cryofacies' can be defined according to patterns of sediment characterized by distinct ice lenses and layers, volumetric ice content and ice-crystal size. Cryofacies can be subdivided according to cryostructure. Where a number of cryofacies form a distinctive cryostratigraphic unit, these are termed a 'cryofacies assemblage'. The recognition, if present, of (i) thaw unconformities, (ii) other ice bodies such as vein ice (ice wedges), aggradational ice and thermokarst-cave ('pool') ice, and (iii) ice, sand and gravelly pseudomorphs is also important in determining the nature of the freezing process, the conditions under which frozen sediment accumulates, and the history of permafrost. © 2010 Elsevier B.V.
Nash J.C.,University of Ottawa |
Varadhan R.,Johns Hopkins University
Journal of Statistical Software | Year: 2011
R users can often solve optimization tasks easily using the tools in the optim function in the stats package provided by default on R installations. However, there are many other optimization and nonlinear modelling tools in R or in easily installed add-on packages. These present users with a bewildering array of choices. optimx is a wrapper to consolidate many of these choices for the optimization of functions that are mostly smooth with parameters at most bounds-constrained. We attempt to provide some diagnostic information about the function, its scaling and parameter bounds, and the solution characteristics. optimx runs a battery of methods on a given problem, thus facilitating comparative studies of optimization algorithms for the problem at hand. optimx can also be a useful pedagogical tool for demonstrating the strengths and pitfalls of different classes of optimization approaches including Newton, gradient, and derivative-free methods.
Pereira J.,University of Ottawa
Current Oncology | Year: 2011
Euthanasia or assisted suicide-and sometimes both- have been legalized in a small number of countries and states. In all jurisdictions, laws and safeguards were put in place to prevent abuse and misuse of these practices. Prevention measures have included, among others, explicit consent by the person requesting euthanasia, mandatory reporting of all cases, administration only by physicians (with the exception of Switzerland), and consultation by a second physician. The present paper provides evidence that these laws and safeguards are regularly ignored and transgressed in all the jurisdictions and that transgressions are not prosecuted. For example, about 900 people annually are administered lethal substances without having given explicit consent, and in one jurisdiction, almost 50% of cases of euthanasia are not reported. Increased tolerance of transgressions in societies with such laws represents a social "slippery slope," as do changes to the laws and criteria that followed legalization. Although the initial intent was to limit euthanasia and assisted suicide to a lastresort option for a very small number of terminally ill people, some jurisdictions now extend the practice to newborns, children, and people with dementia. A terminal illness is no longer a prerequisite. In the Netherlands, euthanasia for anyone over the age of 70 who is "tired of living" is now being considered. Legalizing euthanasia and assisted suicide therefore places many people at risk, affects the values of society over time, and does not provide controls and safeguards. © 2011 Multimed Inc.
Tawfic Q.A.,University of Ottawa
Journal of Opioid Management | Year: 2013
Ketamine is a noncompetitive antagonist of N-methyl-D-aspartate receptor. It has been widely used in anesthesia and pain management. Ketamine has been administered via the intravenous, intramuscular, subcutaneous, oral, rectal, topical, intranasal, sublingual, epidural, and caudal routes. Ketamine improves postoperative and posttrauma pain scores and reduces opioid consumption. It has special indication for patients with opioid tolerance, acute hyperalgesia, and neuropathic pain. It also has a role in the management of chronic pain including both cancer and noncancer pain. Recreational use of ketamine is increasing as well through different routes of administration like inhalation, smoking, or intravenous injection. Long-time exposure to ketamine, especially in the abusers, may lead to serious side effects. This review is trying to define the role of ketamine in pain management. © 2013 Journal of Opioid Management, All Rights Reserved.
Bickel D.R.,University of Ottawa
Statistical Applications in Genetics and Molecular Biology | Year: 2013
Multiple comparison procedures that control a family-wise error rate or false discovery rate provide an achieved error rate as the adjusted p-value or q-value for each hypothesis tested. However, since achieved error rates are not understood as probabilities that the null hypotheses are true, empirical Bayes methods have been employed to estimate such posterior probabilities, called local false discovery rates (LFDRs) to emphasize that their priors are unknown and of the frequency type. The main approaches to LFDR estimation, relying either on fully parametric models to maximize likelihood or on the presence of enough hypotheses for nonparametric density estimation, lack the simplicity and generality of adjusted p-values. To begin filling the gap, this paper introduces simple methods of LFDR estimation with proven asymptotic conservatism without assuming the parameter distribution is in a parametric family. Simulations indicate that they remain conservative even for very small numbers of hypotheses. One of the proposed procedures enables interpreting the original FDR control rule in terms of LFDR estimation, thereby facilitating practical use of the former. The most conservative of the new procedures is applied to measured abundance levels of 20 proteins. © 2013 Walter de Gruyter GmbH, Berlin/Boston.
Ingold K.U.,National Research Council Canada |
Pratt D.A.,University of Ottawa
Chemical Reviews | Year: 2014
Antioxidants were divided in two parts radical-trapping antioxidants (RTAs) and preventive antioxidants. By the final quarter of the 20th century, the commercial importance of antioxidants was overshadowed by their putative role in human health, as the implication of radical-mediated oxidation in virtually all types of degenerative diseases, including cancer and aging, emerged. From a commercial perspective, there continues to be significant interest in the development of RTA technology. Much of the industrial research effort has been on optimization of the structures of existing RTAs to provide appropriate physical properties and identification of combinations of existing RTAs that achieve optimal performance via the synergistic interactions.
Corkum P.B.,University of Ottawa |
Corkum P.B.,National Research Council Canada
Physics Today | Year: 2011
In 1906 Ernest Rutherford discovered that א particles deflect as they pass through a mica film. That experiment, which helped Rutherford identify the atomic nucleus, was a dramatic demonstration that collisions between particles could tell us about the structure of matter. Now, a century later, high-energy collisions between subatomic particles have revealed the fundamental building blocks of our world - quarks, muons, and so on - and lower-energy collisions have been central to understanding and harnessing nuclear physics. © 2011 American Institute of Physics.
Moore T.J.,Institute for Safe Medication Practices |
Moore T.J.,George Washington University |
Glenmullen J.,Harvard University |
Mattison D.R.,University of Ottawa
JAMA Internal Medicine | Year: 2014
IMPORTANCE: Severe impulse control disorders involving pathological gambling, hypersexuality, and compulsive shopping have been reported in association with the use of dopamine receptor agonist drugs in case series and retrospective patient surveys. These agents are used to treat Parkinson disease, restless leg syndrome, and hyperprolactinemia. OBJECTIVES: To analyze serious adverse drug event reports about these impulse control disorders received by the US Food and Drug Administration (FDA) and to assess the relationship of these case reports with the 6 FDA-approved dopamine receptor agonist drugs. DESIGN, SETTING, AND PARTICIPANTS: We conducted a retrospective disproportionality analysis based on the 2.7 million serious domestic and foreign adverse drug event reports from 2003 to 2012 extracted from the FDA Adverse Event Reporting System. MAIN OUTCOMES AND MEASURES: Cases were selected if they contained any of 10 preferred terms in the Medical Dictionary for Regulatory Activities (MedDRA) that described the abnormal behaviors. We used the proportional reporting ratio (PRR) to compare the proportion of target events to all serious events for the study drugs with a similar proportion for all other drugs. RESULTS: We identified 1580 events indicating impulse control disorders from the United States and 21 other countries: 710 for dopamine receptor agonist drugs and 870 for other drugs. The dopamine receptor agonist drugs had a strong signal associated with these impulse control disorders (n = 710; PRR = 277.6, P < .001). The association was strongest for the dopamine agonists pramipexole (n = 410; PRR = 455.9, P < .001) and ropinirole (n = 188; PRR = 152.5, P < .001), with preferential affinity for the dopamine D3 receptor. A signal was also seen for aripiprazole, an antipsychotic classified as a partial agonist of the D3 receptor (n = 37; PRR = 8.6, P < .001). CONCLUSIONS AND RELEVANCE: Our findings confirm and extend the evidence that dopamine receptor agonist drugs are associated with these specific impulse control disorders. At present, none of the dopamine receptor agonist drugs approved by the FDA have boxed warnings as part of their prescribing information. Our data, and data from prior studies, show the need for more prominent warnings. Copyright 2014 American Medical Association. All rights reserved.
Boyd R.W.,University of Ottawa |
Boyd R.W.,University of Rochester
Journal of the Optical Society of America B: Optical Physics | Year: 2011
There are two standard methods for controlling the group velocity of light. One makes use of the dispersive properties associated with the resonance structure of a material medium. The other makes use of structural resonances, such as those that occur in photonic crystals. Both procedures have proved useful in a variety of situations. In this work we contrast these two approaches, especially in terms of issues such as the kinematics of energy flow though the system and the resulting implications for the behavior of nonlinear optical processes in these situations. Stated differently, this paper addresses the question of when nonlinear optical processes are enhanced through use of slow-light interactions and when they are not. © 2011 Optical Society of America.
Attaran A.,University of Ottawa
The American journal of tropical medicine and hygiene | Year: 2015
The iatrogenic pandemic of untreated illness related to falsified and substandard medicines is intolerable, but has a logical explanation: in many countries, inadequate laws make it barely illegal to manufacture or distribute poor-quality medicines. The law hardly punishes those who intentionally or recklessly deal in falsified or substandard medicine, when clearly it should criminalize these perpetrators in proportion to the grievous--even fatal--injury they inflict on public health. To solve this omission, this article presents a new Model Law on Medicine Crime, which countries may freely use as a template for strengthening their national laws. The Model Law includes criminal prohibitions against manufacturing, trafficking, or selling poor-quality medicines; principles for appropriately punishing offenders; special provisions for Internet-based medicine crimes; tools for encouraging whistle-blowers to cooperate with law enforcement; incentives for developing governments to strengthen their drug regulatory capacity; and important exceptions to prevent the law being abused, such as to prevent the prosecution of legitimate medical researchers or to prevent good-quality generic medicines being seized while in transit. The Model Law is discussed and explained and is offered free of charge under a Creative Commons license to any governments wanting to implement it. © The American Society of Tropical Medicine and Hygiene.
Byers-Heinlein K.,Concordia University at Montreal |
Fennell C.T.,University of Ottawa
Developmental Psychobiology | Year: 2014
Human infants become native-language listeners through a process of perceptual narrowing. Monolingual infants are initially sensitive to a wide range of language-relevant contrasts. However, as they mature and gain native-language experience, their sensitivity to nonnative contrasts declines. Here, we consider the case of infants growing up bilingual as a window into how increased variation affects early perceptual development. These infants encounter different meaningful contrasts in each of their languages, and must also attend to contrasts that occur between their languages. Bilingual infants share many classic developmental patterns with monolinguals. However, they also show unique developmental patterns in the perception of native distinctions such as U-shaped trajectories and dose-response relationships, and show some enhanced sensitivity to nonnative distinctions. Analogous developmental patterns can be observed in individuals exposed to two nonlinguistic systems in domains such as music and face perception. Some preliminary evidence suggests that bilingual individuals might retain more sensitivity to nonnative contrasts, reaching a less narrow end state than monolinguals. © 2013 Wiley Periodicals, Inc.
Detellier C.,University of Ottawa |
Schoonheydt R.A.,Catholic University of Leuven
Elements | Year: 2014
Kaolinite is one of the most important industrial clay minerals, with a worldwide consumption in the millions of tons per year and applications in a wide range of industrial areas. Traditionally, its most important use has been in the paper and ceramic industries. New, innovative techniques are being developed that are based on intercalation and grafting of kaolinite's unique dipolar layer structure. Such techniques are leading the way to the synthesis of kaolinite-polymer nanocomposites, including bionanocomposites that might have value-added properties benefi ting industry and the health sciences.
Portner O.,University of Ottawa
Clinical Orthopaedics and Related Research | Year: 2014
Background: According to the literature, closing and opening wedge high tibial valgus osteotomies can raise or lower the patella, and diffèrent methods of patella height measurement show similarly conflicting results. Clarification of this was thought to be important because there is much literature describing morbidity secondary to patella alta or patella infera (baja). Effects on tibial slope and patellar tendon length are not well delineated and the influence of sex and age is unknown.Questions/purpose: A group of patients who underwent high tibial valgus osteotomy was investigated to determine how surgical technique influenced postoperative (1) patellar height and (2) tibial slope and patellar tendon length, and (3) whether age or gender independently influenced postoperative patellar height. To eliminate the often conflicting results seen when several ratio methods are used, patellar height was measured by one method, before and after surgery, shown previously to be reliable.Methods: Patellar height was measured on radiographs using the plateau-patella angle in a retrospective case series consisting of three cohorts: 18 patients with closing wedge osteotomies, 26 with opening wedge osteotomies, and 32 with combined osteotomies. The indication for surgery in all three cohorts was medial osteoarthritis with secondary varus. Before surgery there were no significant differences in patellar height, femorotibial angle, age, or gender among the three groups, and no patients were lost to followup during the 8-week study period after surgery. Seven of the 76 patients (9.2%), all in the opening wedge cohort, had concomitant ACL reconstruction at the time of the tibial osteotomy. No other surgery, except arthroscopy, was performed at the time of osteotomy. Patellar tendon length was assessed by the Insall-Salvati index and tibial slope by the angle between the posterior tibial cortex and the medial tibial joint line. Postoperative measurements were made between 6 and 8 weeks. The influence of sex and age was calculated using patellar height measurements made before any surgery.Results: All closing wedge osteotomies produced patellar ascent by an average of 13% (p < 0.001), all opening wedges produced descent by an average of 21% (p < 0.001), and the combined osteotomy mean showed minimal change (p = 0.0034). The absolute consistency of the changes and their direction allow suggested guidelines for selection of osteotomy type. There were only slight changes in tibial slope. A significant change in patellar tendon length was seen in seven knees of the opening wedge cohort that had concomitant ACL reconstruction. All had a mean reduction of the Insall-Salvati index of 0.05 (approximately 5%), p = 0.0002. New findings showed higher patellae in female and older patients, unrelated to the surgery.Conclusions: If it is accepted that patella baja and patella alta should be avoided, then closing wedge osteotomies should be performed only when the patella is low riding, and opening wedge osteotomies should be done only for patients with preexisting patella alta. The combined osteotomy minimizes changes in patellar height. Patellar tendon contractures and tibial slope changes can be avoided. The plateau-patella angle should be measured preoperatively to help decide the type of osteotomy.Level of Evidence: Level III, therapeutic study. See the Instructions for Authors for a complete description of levels of evidence. © 2014, The Author(s).
Spinello D.,University of Ottawa
IEEE Transactions on Automatic Control | Year: 2016
A sensor network with time varying communication links is considered. Data sharing among nodes is described by a stochastic time-varying network topology. Individual estimates are determined by local noisy measurements, and by the independent opinion pool data fusion scheme adapted to the distributed network structure. The sequences describing communication events between pairs of agents are modeled as Markov chains. It is shown that if communication events are recurrent in the stochastic sense, then the error covariance matrices associated with individual estimates are asymptotically independent of the sensor node. This result applies to coupled estimation and motion control with networked systems, for example to establish synchronization results in certain networks that are disconnected at any given time instant. © 2015 IEEE.
Chenu F.,Ottawa Health Research Institute |
El Mansari M.,Ottawa Health Research Institute |
Blier P.,Ottawa Health Research Institute |
Blier P.,University of Ottawa
Neuropsychopharmacology | Year: 2013
Agomelatine is a melatonergic MT1/MT2 agonist and a serotonin (5-HT) 5-HT 2C antagonist. The effects of 2-day and 14-day administration of agomelatine were investigated on the activity of ventral tegmental area (VTA) dopamine (DA), locus coeruleus (LC) norepinephrine (NE), and dorsal raphe nucleus (DRN) 5-HT neurons using in vivo electrophysiology in rats. The 5-HT1A transmission was assessed at hippocampus CA3 pyramidal neurons. After a 2-day regimen of agomelatine (40 mg/kg/day, i.p.), an increase in the number of spontaneously active VTA-DA neurons (p<0.001) and in the firing rate of LC-NE neurons (p<0.001) was observed. After 14 days, the administration of agomelatine induced an increase in: (1) the number of spontaneously active DA neurons (p<0.05), (2) the bursting activity of DA neurons (bursts/min, p<0.01 and percentage of spikes occurring in bursts, p<0.05), (3) the firing rate of DRN-5-HT neurons (p<0.05), and (4) the tonic activation of postsynaptic 5-HT1A receptors located in the hippocampus. The increase in 5-HT firing rate was D2 dependent, as it was antagonized by the D2 receptor antagonist paliperidone. The enhancement of NE firing was restored by the 5-HT2A receptor antagonist MDL-100,907 after the 14-day regimen. All the effects of agomelatine were antagonized by a single administration of the melatonergic antagonist S22153 (except for the increase in the percentage of spikes occurring in burst for DA neurons). The present results suggest that (1) agomelatine exerts direct (2 days) and indirect (14 days) modulations of monoaminergic neuronal activity and (2) the melatonergic agonistic activity of agomelatine contributes to the enhancement of DA and 5-HT neurotransmission. © 2013 American College of Neuropsychopharmacology. All rights reserved.
Fast S.,University of Ottawa
Journal of Rural Studies | Year: 2013
This study pursues a Habermasian analysis of citizen discussions and of the local public sphere to shed light on renewable energy futures in rural east-central Canada. Using data from group discussions, it pursues an investigation of utterances, validity claims and of discourses. The analysis is supplemented by participant observation of publicly acting organizations, and together these form the evidence to arrive at some predictions for energy developments. This case study finds governance officials tended to negotiate solar, wind, biomass and small hydro projects with fact-claims, but citizens operated mainly with norm-claims and this along with other factors creates a distortion in communication and in social coordination with implications for the future of various energy types. More generally it also suggests the state's strong reliance on market incentives may have long term costs in terms of diminished public reasoning over renewable energy. Working through Habermas' concepts in this way also pointed towards potential contributions to the theories of communicative action and the public sphere. © 2013 Elsevier Ltd.
Konkle A.T.M.,University of Ottawa |
McCarthy M.M.,University of Maryland, Baltimore
Endocrinology | Year: 2011
The prevailing view of sexual differentiation of mammalian brain is that androgen synthesized in the fetal and neonatal testis and aromatized centrally during a perinatal sensitive period is the sole source of brain estradiol and the primary determinant of sex differences. Subregions of the diencephalon are among the most sexually dimorphic in the brain, and there are well-established sex differences in the amount of testosterone and estradiol measured in the hypothalamus and preoptic area during the perinatal period. We previously reported unexpectedly high estradiol in the hippocampus and cortex of both male and female newborn rat. This prompted a thorough investigation of the developmental profile of steroids in the rat brain using RIA to quantify the level of estradiol, testosterone, and dihydrotestosterone in discrete subregions of the brain from embryonic d 19 to adulthood. Plasma estradiol levels from individual animals were assessed when sufficient samplewasavailable.Asignificant sex difference in hypothalamic testosterone prior to birth was consistent with previous findings. Postnatally, there was a distinct pattern of changing steroid concentrations in each brain region, and these were unrelated to circulating steroid. Removal of the gonads and adrenals at birth did not significantly reduce steroids in any brain region assayed 3 d later. Aromatase activity was detectable in all brain areas at birth, and the difference in activity level paralleled the observed regional differences in estradiol content. Based on these findings,we propose that steroidogenesis in the brain, independent of peripherally derived precursors, may play a critical role in mammalian brain development of both sexes, beyond the establishment of sex differences. Copyright © 2010 The Endocrine Society. All rights reserved.
Roberts R.,University of Ottawa
Methodist DeBakey cardiovascular journal | Year: 2014
In 2007, the first genetic risk variant, 9p21, was simultaneously discovered by two independent groups. 9p21 increases the risk of coronary artery disease in individuals with premature heart disease by twofold, and in the overall population the heterozygote is associated with a 25% increased risk and the homozygote with a 50% increased risk. It is of note that the risk mediated by 9p21 is independent of known risk factors. Since then, with the development of new technologies and the international consortium of CARDIoGRAM, there is now a total of 50 genetic risk variants confirmed and replicated for CAD. Of these 50, 35 mediate their risk by unknown mechanisms, indicating that the pathogenesis of atherosclerosis and myocardial infarction is due to additional factors as yet unknown. The role of genetic risk factors in the management of CAD is yet to be determined. Since many of them are independent of known risk factors, the genetic risk will in the future have to be incorporated into the guidelines, which recommend the target level of plasma LDL-C to be achieved based on the number of risk factors.
Papp S.,University of Ottawa
Hand Clinics | Year: 2010
Carpal bone fractures make up a significant proportion of injuries to the wrist. The complex bone shape and articulations make diagnosis more difficult and missed injuries more common. This article reviews carpal bone fractures excluding the scaphoid. © 2010 Elsevier Inc. All rights reserved.
Yu M.,University of Ottawa |
Yu M.,Ontario Cancer Institute
Advances in Clinical Chemistry | Year: 2012
Mitochondria are ubiquitous organelles in eukaryotic cells principally responsible for regulating cellular energy metabolism, free radical production, and the execution of apoptotic pathways. Abnormal oxidative phosphorylation (OXPHOS) and aerobic metabolism as a result of mitochondrial dysfunction have long been hypothesized to be involved in tumorigenesis. In the past decades, numerous somatic mutations in both the coding and control regions of mitochondrial DNA (mtDNA) have been extensively examined in a broad range of primary human cancers, underscoring that accumulation of mtDNA alterations may be a critical factor in eliciting persistent mitochondrial defects and consequently contributing to cancer initiation and progression. However, the roles of these mtDNA mutations in the carcinogenic process remain largely unknown. This review outlines a wide variety of somatic mtDNA mutations identified in common human malignancies and highlights recent advances in understanding the causal roles of mtDNA variations in neoplastic transformation and tumor progression. In addition, it briefly illustrates how mtDNA alterations activate mitochondria-to-nucleus retrograde signaling so as to modulate the expression of relevant nuclear genes or induce epigenetic changes and promote malignant phenotypes in cancer cells. The present state of our knowledge regarding how mutational changes in the mitochondrial genome could be used as a diagnostic biomarker for early detection of cancer and as a potential target in the development of new therapeutic approaches is also discussed. These findings strongly indicate that mtDNA mutations exert a crucial role in the pathogenic mechanisms of tumor development, but continued investigations are definitely required to further elucidate the functional significance of specific mtDNA mutations in the etiology of human cancers.Copyright 2012, Elsevier Inc.
Potvin Kent M.,University of Ottawa |
Wanless A.,Independent Consultant
International Journal of Obesity | Year: 2014
Objective: To assess whether children's exposure to television food/beverage advertising has changed since the implementation of the self-regulatory Canadian Children's Food and Beverage Advertising Initiative (CAI).Design:Data on 11 advertised food/beverage categories (candy, chocolate bars, cookies, portable snacks, cheese, yogurt, cereal, juices, soft drinks, diet soft drinks and fast food) were purchased from Nielsen Media Research for May 2006, 2009 and 2011 for the broadcasting markets of Toronto and Vancouver. The number of advertisements aired on 27 television stations between 0600 hours-1200 hours was determined in Toronto and Vancouver for May 2006, 2009 and 2011 and the percentage change in the number of spots between May 2006 and May 2011 on all stations, on children's specialty stations and on generalist stations was then calculated. The average number food/beverage spots seen by children aged 2-11 was determined for May 2006 and 2009 and the percentage change was calculated.Results:On children's specialty channels, a 4.5% decrease in total spots aired was observed while spots aired on generalist stations increased by 44% (Toronto) and 45% (Vancouver). On all stations, children's total average exposure to food/beverage advertising increased by 16.8% in Toronto and 6.4% in Vancouver between 2006 and 2009. Significant increases were seen in snacks and yogurt in both cities, and in fast food in Toronto. On children's specialty channels, children's exposure to the food/beverage categories considered increased by 5.4% in Toronto and by 2.5% in Vancouver.Conclusions:Despite improvements in the volume of spots on children's specialty channels, children's exposure to food and beverage advertising has increased since the implementation of the CAI. The current self-regulatory system is failing to protect children from food marketing high in fat, sugar and sodium on television. Government regulation needs to be considered. © 2014 Macmillan Publishers Limited All rights reserved.
Saha M.,University of British Columbia |
Eskicioglu C.,University of British Columbia |
Marin J.,University of Ottawa
Bioresource Technology | Year: 2011
Microwave (2450 MHz, 1250 W), ultrasonic (20 kHz, 400 W) and chemo-mechanical (MicroSludge® with 900. mg/L NaOH followed by 83,000 kPa) pretreatments were applied to pulp mill waste sludge to enhance methane production and reduce digester sludge retention time. The effects of four variables (microwave temperature in a range of 50-175°C) and sonication time (15-90. min), sludge type (primary or secondary) and digester temperature (mesophilic and thermophilic) were investigated. Microwave pretreatment proved to be the most effective, increasing specific methane yields of WAS samples by 90% compared to controls after 21. days of mesophilic digestion. Sonication solubilized the sludge samples better, but resulted in soluble non-biodegradable compounds. Based on the laboratory scale data, MicroSludge® was found the least energy intensive pretreatment followed by sonication for 15. min alternative with net energy profits of 1366 and 386. kWh/tonne of total solids (TS), respectively. Pretreatment benefits were smaller for thermophilic digesters. © 2011 Elsevier Ltd.
Rodrigue N.,Agriculture and Agri Food Canada |
Rodrigue N.,University of Ottawa
Genetics | Year: 2013
Phylogeny-based modeling of heterogeneity across the positions of multiple-sequence alignments has generally been approached from two main perspectives. The first treats site specificities as random variables drawn from a statistical law, and the likelihood function takes the form of an integral over this law. The second assigns distinct variables to each position, and, in a maximum-likelihood context, adjusts these variables, along with global parameters, to optimize a joint likelihood function. Here, it is emphasized that while the first approach directly enjoys the statistical guaranties of traditional likelihood theory, the latter does not, and should be approached with particular caution when the site-specific variables are high dimensional. Using a phylogeny-based mutation-selection framework, it is shown that the difference in interpretation of site-specific variables explains the incongruities in recent studies regarding distributions of selection coefficients. © 2013 Her Majesty the Queen in the Right of Canada.
Atance C.M.,University of Ottawa
Child Development Perspectives | Year: 2015
Thinking about the future has become a focus of study in both adult and childhood cognition. Of special interest is the capacity to mentally pre-experience future events that involve the self (or episodic future thinking) and how this capacity relates to other aspects of cognition, including memory. In this article, I review developmental psychologists' approaches to exploring this construct in preschool-age children. I highlight the strengths and limits of these approaches and suggest ways to further develop tasks that test future thinking. I then provide a brief overview of theories arguing for close links between episodic future thinking and memory, and episodic future thinking and theory of mind, along with relevant developmental data. I conclude by discussing challenges and directions in this area of research, including the need to identify more clearly the behaviors that reflect future thinking ability and when these develop. © 2015 The Society for Research in Child Development.
Hanthorn J.J.,Queens University |
Valgimigli L.,University of Bologna |
Pratt D.A.,Queens University |
Pratt D.A.,University of Ottawa
Journal of the American Chemical Society | Year: 2012
The incorporation of nitrogen atoms into the aryl rings of conventional diphenylamine antioxidants enables the preparation of readily accessible, air-stable analogues, several of which have temperature-independent radical-trapping activities up to 200-fold greater than those of typical commercial diphenylamines. Amazingly, the nitrogen atoms raise the oxidation potentials of the amines without greatly changing their radical-trapping (H-atom transfer) reactivity. © 2012 American Chemical Society.
Chu T.,Brock University |
Korobkov I.,University of Ottawa |
Nikonov G.I.,Brock University
Journal of the American Chemical Society | Year: 2014
The Al(I) compound NacNacAl (1, NacNac = [ArNC(Me)CHC(Me)NAr]- and Ar = 2,6-Pri 2C6H3) reacts with H-X (X = H, Si, B, Al, C, N, P, O) σ bonds of H2, silanes, borane (HBpin, pin = pinacolate), allane (NacNacAlH2), phosphine (HPPh2), amines, alcohol (PriOH), and Cp H (Cp* = pentamethylcyclopentadiene) to give a series of hydride derivatives of the four-coordinate aluminum NacNacAlH(X), which are characterized herein by spectroscopic methods (NMR and IR) and X-ray diffraction. This method allows for the syntheses of the first boryl hydride of aluminum and novel silyl hydride and phosphido hydride derivatives. In the case of the addition of NacNacAlH 2, the reaction is reversible, proving the possibility of reductive elimination from the species NacNacAlH(X). © 2014 American Chemical Society.
Andreguetto Maciel G.,Sao Paulo State University |
Lutscher F.,University of Ottawa
American Naturalist | Year: 2013
How individual-level movement decisions in response to habitat edges influence population-level patterns of persistence and spread of a species is a major challenge in spatial ecology and conservation biology. Here, we integrate novel insights into edge behavior, based on habitat preference and movement rates, into spatially explicit growth-dispersal models. We demonstrate how crucial ecological quantities (e.g., minimal patch size, spread rate) depend critically on these individual-level decisions. In particular, we find that including edge behavior properly in these models gives qualitatively different and intuitively more reasonable results than those of some previous studies that did not consider this level of detail. Our results highlight the importance of new empirical work on individual movement response to habitat edges. © 2013 by The University of Chicago.
Forrest J.R.K.,University of Ottawa
Oikos | Year: 2015
Climate change can affect plant-pollinator interactions in a variety of ways, but much of the research attention has focused on whether independent shifts in phenology will alter temporal overlap between plants and pollinators. Here I review the research on plant-pollinator mismatch, assessing the potential for observational and experimental approaches to address particular aspects of the problem. Recent, primarily observational studies suggest that phenologies of co-occurring plants and pollinators tend to respond similarly to environmental cues, but that nevertheless, certain pairs of interacting species are showing independent shifts in phenology. Only in a few cases, however, have these independent shifts been shown to affect population vital rates (specifically, seed production by plants) but this largely reflects a lack of research. Compared to the few long-term studies of pollination in natural plant populations, experimental manipulations of phenology have yielded relatively optimistic conclusions about effects of phenological shifts on plant reproduction, and I discuss how issues of scale and frequency-dependence in pollinator behaviour affect the interpretation of these 'temporal transplant' experiments. Comparable research on the impacts of mismatch on pollinator populations is so far lacking, but both observational studies and focused experiments have the potential to improve our forecasts of pollinator responses to changing phenologies. Finally, while there is now evidence that plant-pollinator mismatch can affect seed production by plants, it is still unclear whether this phenological impact will be the primary way in which climate change affects plant-pollinator interactions. It would be useful to test the direct effects of changing climate on pollinator population persistence, and to compare the importance of phenological mismatch with other threats to pollination. © 2014 The Authors.
Farhadi A.,University of Ottawa |
Charalambous C.D.,University of Cyprus
Automatica | Year: 2010
In this paper we present an encoder, decoder and a stabilizing controller for reliable data reconstruction and robust stability of uncertain dynamic systems controlled over Additive White Gaussian Noise (AWGN) channels. The uncertainty in the dynamic system is described by a relative entropy constraint. Such an uncertainty description is a natural stochastic generalization of the sum quadratic uncertainty description. This paper complements the results of Farhadi and Charalambous (2008) by showing that the necessary condition presented there can be tight. This is shown by designing an encoder, decoder and a stabilizing controller. © 2010 Elsevier Ltd. All rights reserved.
Nash J.C.,University of Ottawa
Journal of Statistical Software | Year: 2014
R (R Core Team 2014) provides a powerful and flexible system for statistical computations. It has a default-install set of functionality that can be expanded by the use of several thousand add-in packages as well as user-written scripts. While R is itself a programming language, it has proven relatively easy to incorporate programs in other languages, particularly Fortran and C. Success, however, can lead to its own costs:• Users face a confusion of choice when trying to select packages in approaching a problem.• A need to maintain workable examples using early methods may mean some tools offered as a default may be dated.• In an open-source project like R, how to decide what tools offer “best practice” choices, and how to implement such a policy, present a serious challenge.We discuss these issues with reference to the tools in R for nonlinear parameter estimation (NLPE) and optimization, though for the present article ‘optimization’ will be limited to function minimization of essentially smooth functions with at most bounds constraints on the parameters. We will abbreviate this class of problems as NLPE. We believe that the concepts proposed are transferable to other classes of problems seen by R users. © 2014, American Statistical Association. All rights reserved.
Daff T.D.,University of Ottawa |
De Leeuw N.H.,University College London
Journal of Materials Chemistry | Year: 2012
Density functional theory calculations of the adsorption of hydrazine (N 2H 4) on the copper (111), (100) and (110) surfaces have shown that the surface structure is key in determining the thermodynamics of adsorption, with low coordinated atoms, resulting from the surface geometry, providing sites for strong adsorption. Although the uneven structure of the (110) surface allows for the strongest binding of molecular hydrazine through bridging between surface atoms, the addition of adatoms to the otherwise more stable and flatter (111) and (100) surfaces provides sites that enable binding to almost the same extent. The thermodynamics of dissociative adsorption by breaking of the hydrazine N-N bond show that this binding mode is strongly favoured over molecular adsorption both on the planar surfaces and at the adatoms. The strength of adsorption is shown to increase with decreasing surface stability, with adsorption energies for dissociative adsorption ranging from 229 kJ mol -1 to 257 kJ mol -1, whereas molecular hydrazine adsorbs with the release of 94 kJ mol -1 to 107 kJ mol -1. © 2012 The Royal Society of Chemistry.
Elgar F.J.,Carleton University |
Aitken N.,University of Ottawa
European Journal of Public Health | Year: 2011
Background: Theories of why income inequality correlates with violence suggest that inequality erodes social capital and trust, or inhibits investment into public services and infrastructure. Past research sensed the importance of these causal paths but few have examined them using tests of statistical mediation. Methods: We explored links between income inequality and rates of homicide in 33 countries and then tested whether this association is mediated by an indicator of social capital (interpersonal trust) or by public spending on health and education. Survey data on trust were collected from 48 641 adults and matched to country data on per capita income, income inequality, public expenditures on health and education and rate of homicides. Results: Between countries, income inequality correlated with trust (r = -0.64) and homicide (r = 0.80) but not with public expenditures. Trust also correlated with homicides (r = -0.58) and partly mediated the association between income inequality and homicide, whilst public expenditures did not. Multilevel analysis showed that income inequality related to less trust after differences in per capita income and sample characteristics were taken into account. Conclusion: Results were consistent with psychosocial explanations of links between income inequality and homicide; however, the causal relationship between inequality, trust and homicide remains unclear given the cross-sectional design of this study. Societies with large income differences and low levels of trust may lack the social capacity to create safe communities. © The Author 2010.
van der Velden M.,University of Oslo |
El Emam K.,Ottawa Hospital Research Institute |
El Emam K.,University of Ottawa
Journal of the American Medical Informatics Association | Year: 2013
Background: The literature describes teenagers as active users of social media, who seem to care about privacy, but who also reveal a considerable amount of personal information. There have been no studies of how they manage personal health information on social media. Objective: To understand how chronically ill teenage patients manage their privacy on social media sites. Design: A qualitative study based on a content analysis of semistructured interviews with 20 hospital patients (12e18 years). Results: Most teenage patients do not disclose their personal health information on social media, even though the study found a pervasive use of Facebook. Facebook is a place to be a "regular", rather than a sick teenager. It is a place where teenage patients stay up-to-date about their social lifedit is not seen as a place to discuss their diagnosis and treatment. The majority of teenage patients don't use social media to come into contact with others with similar conditions and they don't use the internet to find health information about their diagnosis. Conclusions: Social media play an important role in the social life of teenage patients. They enable young patients to be "regular" teenagers. Teenage patients' online privacy behavior is an expression of their need for self-definition and self-protection.
Stapleton J.M.,University of Ottawa
Journal of occupational and environmental hygiene | Year: 2011
This study evaluated the influence of activewear undergarments worn under the standard mining coveralls on whole-body heat exchange and change in body heat content during work in the heat. Each participant performed 60 min of cycling at a constant rate of heat production of 400 W followed by 60 min of recovery in a whole-body calorimeter regulated at 40°C and 15% relative humidity donning one of the four clothing ensembles: (1) cotton underwear and shorts only (Control, CON); (2) Activewear only (ACT); (3) Coveralls+Cotton undergarments (COV+COT); or (4) Coveralls+Activewear undergarments (COV+ACT). In the latter two conditions a hard hat with earmuffs, gloves, and socks with closed toe shoes were worn. We observed that both COV+COT and COV+ACT resulted in a similar mean (±SE) change in body heat content, which was significantly greater compared with the CON and ACT during exercise, suggesting that the rate of thermal strain was elevated to a similar degree in both coverall conditions (CON: 245±32 kJ; ACT: 260±29 kJ; COV+COT: 428±36 kJ; COV+ACT: 466±15 kJ; p<0.001). During recovery, the negative change in body heat content was greater for both COV+COT and COV+ACT compared with the CON and ACT but similar between COV+COT and COV+ACT due to the greater amount of heat stored during exercise (CON: -83±16 kJ; ACT: -104±33 kJ; COV+COT: -198±30 kJ; COV+ACT: -145±12 kJ; p=0.048). Core temperatures and heart rate were also significantly elevated for the COV+COT and COV+ACT compared with the CON and ACT conditions during and following exercise (p<0.05). These results suggest that while activewear undergarments are not detrimental, they provide no thermoregulatory benefit when replacing the cotton undergarment worn under the standard coverall during work in the heat.
Johnson D.,Carleton University |
Weiss B.,University of Ottawa
Sports Medicine and Arthroscopy Review | Year: 2012
Operations to treat meniscal injuries rank among the most frequent procedures performed by orthopedic surgeons. Ongoing research into the natural history, basic science, and biomechanics of meniscal injury has highlighted the importance of preserving the meniscus to maintain normal knee biomechanics and function. The arthroscopic inside-out suture repair is currently the gold standard by which other meniscal repair techniques are judged. Although it is difficult to identify meniscal tears amenable to repair preoperatively, an assessment of patient factors and tear characteristics on the basis of magnetic resonance imaging and intraoperative findings will aid the decision to excise or repair. For successful repair the meniscal tear must have appropriate location and characteristics, without evidence of fraying or degeneration. Repair with the arthroscopic inside-out method affords anatomic reduction of the meniscus tear and allows stimulation of circulation, factors which contribute to healing of the repair. Coupled with careful dissection and needle placement, this method minimizes complications associated with meniscus repair. Copyright © 2012 by Lippincott Williams & Wilkins.
Parent M.M.,University of Ottawa
Journal of Sport Management | Year: 2010
The purpose of this article was to examine how the decision-making process changes as a major sport event's organizing committee moves from the planning to the implementation to the wrap-up modes. A case study of the 1999 Pan American Games, its organizing committee, and its stakeholders was built by means of interviews and archival material. Velocity impacted decision making in different ways. First, the importance of the time, context, and resources parameters changed, as did the model of decision making (from administrative to garbage can to rational). As well, four drivers of decision making (structural dimensions, stakeholder interactions, information management, and personal characteristics) were found. A key strategy for decision makers faced with an increasing velocity environment was planning for the need to react (come Games time) through risk assessments and contingency plans.© 2010 Human Kinetics, Inc.
Poitras S.,University of Ottawa
Spine | Year: 2012
Individual semistructured qualitative interviews. To evaluate barriers to use of management recommendations, aimed at preventing low back pain (LBP) disability, with general practitioners (GPs), occupational therapists (OTs), and physiotherapists (PTs) working in Quebec (Canada), and identify areas of convergence and divergence between health professions. Studies have demonstrated inadequacies of practices of clinicians with regard to LBP management and prevention of persistent disability. Barriers to use of evidence by clinicians should be evaluated to understand these inadequacies and develop implementation strategies. Sixteen PTs, 8 OTs, and 8 GPs were recruited with different levels of experience and practice location (urban or rural). They were asked to follow management recommendations (Clinic on Low-back Pain in Interdisciplinary Practice [CLIP] guidelines), with a minimum of 2 patients. Individual semistructured interviews were used to identify barriers to use of management recommendations aimed at preventing LBP disability. Barriers between health professions were compared. Barriers to use were lesser for OTs and greater for GPs, with divergences among PTs. OTs agreed with the guidelines, found them compatible with their current practice, and thought that using them would prevent persistent disability. GPs and PTs thought that the guidelines did not provide enough information on the pathophysiological management of LBP. GPs thought that it would be difficult to implement the guidelines in everyday practice. All 3 groups thought that management recommendations could conflict with patient expectations. To address identified barriers, a process of care is proposed by fitting tasks to the most compatible providers. The task of GPs could focus on pain management through medication, red flag screening, encouragement to stay active, and reassurance. The tasks of PTs could center on pain management, general exercise, and encouragement to stay active. The tasks of OTs could focus on disability prognosis, yellow flags management, and return to activity parameters. The efficacy of this process of care to prevent persistent LBP disability should be assessed in a trial.
Kovesi T.,University of Ottawa
Diseases of the Esophagus | Year: 2013
Despite early surgical repair, congenital esophageal atresia with or without tracheoesophageal fistula (EA ± TEF) has long-term effects on respiratory and gastrointestinal function. This review updates summarizes research published since 2003 on long-term respiratory complications in patients with a history of EA ± TEF. Pulmonary hypoplasia appears to not be rare in patients with EA ± TEF. Tracheomalacia is common and is associated with respiratory symptoms in childhood. Aspiration, associated with esophageal dysmotility and/or gastroesophageal reflux, may lead to reduced pulmonary function and bronchiectasis. Pulmonary function is generally normal, although lower than in control patients, and restrictive defects tend to be commoner than obstructive defects. Abnormal airway reactivity is common and, along with respiratory symptoms, is associated with atopy. However, the inflammatory profile in EA ± TEF patients based on bronchial biopsies and exhaled nitric oxide differs from typical allergic asthma. Recent studies suggest that in older patients, respiratory symptoms tend to be associated with atopy, but abnormal lung function tends to be associated with gastroesophageal reflux and with chest wall abnormalities. Early detection and management of aspiration may be important to help prevent decrements in pulmonary function and serious long-term complications in EA ± TEF patients. © 2013 Wiley Periodicals, Inc. and the International Society for Diseases of the Esophagus.
Corradi N.,University of Ottawa |
Slamovits C.H.,Dalhousie University
Briefings in Functional Genomics | Year: 2011
Microsporidia are a group of highly adapted unicellular fungi that are known to infect a wide range of animals, including humans and species of great economic importance. These organisms are best known for their very simple cellular and genomic features, an adaptive consequence of their obligate intracellular parasitism. In the last decade, the acquisition of a large amount of genomic and transcriptomic data from severalmicrosporidian species has greatly improved our understanding of the consequences of a purely intracellular lifestyle. In particular, genome sequence data from these pathogens has revealed how obligate intracellular parasitism can result in radical changes in the composition and structure of nuclear genomes and how these changes can affect cellular and evolutionary mechanisms that are otherwise well conserved among eukaryotes. This article reviews our current understanding of the genome content and structure ofmicrosporidia, discussing their evolutionary origin and cataloguing themechanisms that have often been involved in their extreme reduction. © The Author 2010. Published by Oxford University Press. All rights reserved.
Lippel K.,University of Ottawa
Canadian journal of public health. Revue canadienne de santé publique | Year: 2010
This article reports on a study of the legal and policy framework governing access, in Canada, to workers' compensation benefits for workers who are work disabled because of mental health problems attributed to stressful working conditions and events. It also provides a brief description of legislation regulating psychological harassment in Quebec and Saskatchewan. Applying classic legal methodology, the article examines the legal situation in Canada, relying on federal and provincial legislation and case law. While many of the jurisdictions studied explicitly restrict compensability to the consequences of traumatic incidents, application of this legislation is very different from one province to the next. In some provinces, legal exclusions are applied emphatically, whereas in others the workers' compensation appeal tribunals interpret the legislative exclusions much more narrowly, allowing for some access to compensation despite the legislative exclusions. Other provinces have no such exclusions and accept claims for both acute and chronic stress, although access to compensation remains more difficult for claimants with mental health problems than for those who are physically injured, regardless of where they live. The article concludes by offering an analysis of the consequences of the current situation from a public policy and public health perspective, notably underlining the negative consequences, particularly for women, of current workers' compensation policy in most Canadian provinces.
Brunelle M.,University of Ottawa
The Journal of the Acoustical Society of America | Year: 2012
The perceptual integrality of f0, F1 and voice quality is investigated by looking at register, a phonological contrast that relies on these three properties in three dialects of Cham, an Austronesian language of Mainland Southeast Asia. The results of a Garner classification experiment confirm that the three acoustic properties integrate perceptually and that their patterns of integrality are similar in the three dialects. Moreover, they show that dialect-specific sensitivity to acoustic properties can cause salient dimensions to override weaker ones. Finally, the patterns of integrality found in Cham suggest that auditory integrality is not limited to acoustically similar properties.
Sankoff D.,University of Ottawa |
Zheng C.,University of Montreal |
Zhu Q.,Princeton University
BMC Genomics | Year: 2010
Background: Genome amplification through duplication or proliferation of transposable elements has its counterpart in genome reduction, by elimination of DNA or by gene inactivation. Whether loss is primarily due to excision of random length DNA fragments or the inactivation of one gene at a time is controversial. Reduction after whole genome duplication (WGD) represents an inexorable collapse in gene complement.Results: We compare fifteen genomes descending from six eukaryotic WGD events 20-450 Mya. We characterize the collapse over time through the distribution of runs of reduced paralog pairs in duplicated segments. Descendant genomes of the same WGD event behave as replicates. Choice of paralog pairs to be reduced is random except for some resistant regions of contiguous pairs. For those paralog pairs that are reduced, conserved copies tend to concentrate on one chromosome.Conclusions: Both the contiguous regions of reduction-resistant pairs and the concentration of runs of single copy genes on a single chromosome are evidence of transcriptional co-regulation, dosage sensitivity or other functional interaction constraining the reduction process. These constraints and their evolution over time show a consistent pattern across evolutionary domains and a highly reproducible pattern, as replicates, for the several descendants of a single WGD. © 2010 Sankoff et al; licensee BioMed Central Ltd.
Tremblay M.S.,University of Ottawa
Canadian Journal of Public Health | Year: 2012
This manuscript briefly reviews 15 significant initiatives related to childhood obesity and physical inactivity in Canada between September 2010 and September 2011. These include the: announcement of a Federal-Provincial-Territorial framework for action to promote healthy weights; implementation of the nutrition labeling initiative; launch of the CBC "Live Right Now" campaign; announcement of the Public Health Agency of Canada's innovation strategy funding related to obesity; publication of the Canadian Health Measures Survey physical activity findings; release of new Canadian physical activity and sedentary behaviour guidelines; launch of ParticipACTION's "Think Again" campaign; workshop on building trust to address the epidemic of obesity; start of the Canadian Pediatric Weight Management Registry; initiation of "Our Health Our Future: A National Dialogue on Healthy Weights" release of the Active Healthy Kids Canada Report Card on Physical Activity for Children and Youth; National Obesity Summit; Nature Play Day and Sports Day in Canada; development of the Canadian Assessment of Physical Literacy; and the creation of Active Canada 20/20 - A National Physical Activity Plan. The diversity and intensity of activity addressing the childhood obesity and physical inactivity "epidemic" in Canada is encouraging and must be maintained and enhanced. © Canadian Public Health Association, 2012. All rights reserved.
O'Byrne P.,University of Ottawa
Public Health Nursing | Year: 2012
In this article, an argument is put forth that clinic-based HIV testing can function as an important aspect of public health HIV prevention. This assertion is not an outright declaration that all HIV testing is beneficial. Instead, it is the conclusion that the individual-focused initiative of HIV testing could, if structured properly, induce population-level HIV prevention benefits. This analysis was informed using the impact fraction model, the Anderson-May equation, current epidemiological information about HIV from Canada, the United States, and England, and the extant literature on the dynamics of HIV transmission. This conclusion could help inform the development of public and population health HIV testing and HIV prevention policies/practices. © 2012 Wiley Periodicals, Inc.
Fafard P.,University of Ottawa
Journal of Urban Health | Year: 2012
Drug addiction is a major public health problem, one that is most acutely felt in major cities around the globe. Harm reduction and safe injection sites are an attempt to address this problem and are at the cutting edge of public health policy and practice. One of the most studied safe injection sites is INSITE located in Vancouver, British Columbia. Using INSITE as a case study, this paper argues that knowledge translation offers a limited framework for understanding the development of public health policy. This paper also argues that the experience of INSITE suggests that science and social justice, the meta-ideas that lie at the core of the public health enterprise, are an inadequate basis for a theory of public health policy making. However, on a more positive note, INSITE also shows the value of concepts drawn from the ways in which political science analyzes the policy process. © 2012 The New York Academy of Medicine.
Jacob J.D.,University of Ottawa
Journal of Forensic Nursing | Year: 2012
The objective of this paper is to present the results obtained from a qualitative research study conducted a forensic psychiatric setting and to explore the dual role associated with being both "agents of care and agents of social control." Following the narratives provided by nurses working this field, the analysis that follows will problematize the rhetoric of therapy forensic psychiatric nursing. order to support the analysis, this article comprises four sections. The first section will briefly review the study's methodological considerations. Using a combination of Foucault and Goffman's work, the second section provides an empirical contextualization of correctional environments and their effects on nursing care. The third section explains the effects of having a contradictory mandate of care and custody from Festinger's (1957) theory of cognitive dissonance. Lastly, the fourth section provides a critique of disciplinary interventions forensic psychiatric nursing, as it is explained by the participants. © 2012 International Association of Forensic Nurses.
Lippel K.,University of Ottawa
American Journal of Industrial Medicine | Year: 2012
Background: Workers' compensation systems are among the most generous disability insurance systems in North America, although they are also known to be potentially adversarial and may have iatrogenic effects on claimants. This article examines issues to be considered to ensure fair compensation provided in a way that respects the dignity of workers. Methods: An overview of the literature on characteristics and effects of workers' compensation systems is followed by an analysis based on classic legal methods, including those of comparative law, complemented with interview data to examine three models of disability compensation. Results: The first part of the article identifies cross cutting issues to be considered in the examination of the equity of compensation systems and the protection of the dignity of claimants. These include three underpinnings of workers' compensation: the links between a "no-fault" system and the adversarial process, the appropriate use of medical and scientific evidence in the determination of compensability and the application of appropriate measures for promoting return to work. The second part looks at accident compensation in New Zealand, where compensation is available regardless of the cause of the accident, and disability insurance in the Netherlands, where compensation is available regardless of the cause of the disability. It then describes a composite of characteristics favorable to equity drawn from the thirteen workers' compensation systems in Canada. Conclusion: Systems that succeed in reducing opportunities for adversarial interactions and that provide substantive protection could better promote the dignity of claimants. © 2012 Wiley Periodicals, Inc.
Patrick J.,University of Ottawa
Health Care Management Science | Year: 2012
Managing an efficient outpatient clinic can often be complicated by significant no-show rates and escalating appointment lead times. One method that has been proposed for avoiding the wasted capacity due to no-shows is called open or advanced access. The essence of open access is "do today's demand today". We develop a Markov Decision Process (MDP) model that demonstrates that a short booking window does significantly better than open access. We analyze a number of scenarios that explore the trade-off between patient-related measures (lead times) and physician- or system-related measures (revenue, overtime and idle time). Through simulation, we demonstrate that, over a wide variety of potential scenarios and clinics, the MDP policy does as well or better than open access in terms of minimizing costs (or maximizing profits) as well as providing more consistent throughput. © 2011 Springer Science+Business Media, LLC.
Blier P.,Ottawa Health Research Institute |
Blier P.,University of Ottawa |
El-Mansari M.,Ottawa Health Research Institute
Philosophical Transactions of the Royal Society B: Biological Sciences | Year: 2013
The serotonin (5-HT, 5-hydroxytryptamine) system has been implicated in the pathogenesis of major depressive disorder (MDD). The case for its contribution to the therapeutic efficacy of a wide variety of antidepressant treatments is, however, much stronger. All antidepressant strategies have been shown to enhance 5-HT transmission in the brain of laboratory animals. Catecholamines, norepinephrine (NE) and dopamine (DA) can also play a pivotal role in the mechanism of action of certain antidepressant strategies. The enhancement of 5-HT transmission by selective serotonin reuptake inhibitors, which leads to a dampening of the activity of NE and DA neurons, may account in part for the low remission rate achieved with these medications and/or the residuals symptoms after remission is achieved. The functional connectivity between the 5-HT, NE and DA systems can be used to understand the mechanism of action of a wide variety of augmentation strategies in treatment-resistant MDD. Proof-of-concept studies have shown that antidepressant medications with complementary mechanisms of action on monoaminergic systems can double the remission rate achieved in a trial of standard duration. Novel approaches are also being used to treat MDD, which also appear to involve the monoaminergic system(s) to a varying extent. © 2013 The Author(s) Published by the Royal Society. All rights reserved.
Anthony E.J.,University of Ottawa
Greenhouse Gases: Science and Technology | Year: 2013
Many technologies are now being explored to permit the combustion of fossil fuels while achieving CO2 capture in a state suitable for compression, transporting, and sequestration. Among the chief contenders are processes in which the fuel is first decarbonized, usually by gasification, followed by the use of a shift reaction to produce pure H2; post-combustion capture, in which the CO2 is removed from the flue gases either at high temperatures (e.g. carbonate or Ca looping) or at near-ambient temperatures (e.g. amine scrubbing); chemical looping in which the fuel is converted in the presence of a solid oxide carrier, thus producing a stream of gas consisting primarily of CO2 and H2O; and finally, oxyfuel combustion in which the fuel is burned in a stream of pure, or nearly pure, oxygen. The latter technology is already being investigated for application with pulverized fuel or coal, but more recently, the possibility of using oxyfuel combustion with circulating fluidized beds has been receiving increasing attention. There is already a 30 MWth demonstration unit operating in Spain, with plans to build a 300 MWe plant. This perspective describes the current status of oxyfuel research and development. © 2013 Society of Chemical Industry and John Wiley & Sons, Ltd Copyright © 2013 Society of Chemical Industry and John Wiley & Sons, Ltd.
Chaput J.-P.,Eastern Research Group |
Doucet E.,University of Ottawa |
Tremblay A.,Laval University
Obesity Reviews | Year: 2012
Obesity is characterized by the accumulation of excess body fat and can be conceptualized as the physical manifestation of chronic energy excess. An important challenge of today's world is that our so-called obesogenic environment is conducive to the consumption of energy and unfavourable to the expenditure of energy. The modern, computer-dependent, sleep-deprived, physically inactive humans live chronically stressed in a society of food abundance. From a physiological standpoint, the excess weight gain observed in prone individuals is perceived as a normal consequence to a changed environment rather than a pathological process. In other words, weight gain is a sign of our contemporary way of living or a 'collateral damage' in the physiological struggle against modernity. Additionally, substantial body fat loss can complicate appetite control, decrease energy expenditure to a greater extent than predicted, increase the proneness to hypoglycaemia and its related risk towards depressive symptoms, increase the plasma and tissue levels of persistent organic pollutants that promote hormone disruption and metabolic complications, all of which are adaptations that can increase the risk of weight regain. In contrast, body fat gain generally provides the opposite adaptations, emphasizing that obesity may realistically be perceived as an a priori biological adaptation for most individuals. Accordingly, prevention and treatment strategies for obesity should ideally target the main drivers or root causes of body fat gain in order to be able to improve the health of the population. © 2012 The Authors. obesity reviews © 2012 International Association for the Study of Obesity.
Pullman L.,University of Ottawa |
Seto M.C.,Health Integrated
Child Abuse and Neglect | Year: 2012
Objective: Adolescent sex offenders (ASOs) are commonly considered a special kind of juvenile offender, with distinct risk and etiological factors from other adolescent offenders. However, a growing body of research suggests that ASOs are more similar to other adolescent non-sex offenders than they are different (e.g., Awad, Saunders, & Levine, 1984; Elliott, 1994; France & Hudson, 1993). The purpose of the present article is to review recent literature pertaining to the distinction between generalist and specialist adolescent sex offenders (ASOs). Method: This article summarizes the findings from Seto and Lalumière's (2010) metaanalysis on theoretically derived risk and etiological factors for adolescent sexual offending. Based on these findings, recommendations for the assessment and treatment of this population are made. Results: The results of Seto and Lalumière's (2010) meta-analysis suggests the majority of ASOs are generalist offenders who are similar to other adolescent non-sex offenders, while a minority of ASOs are specialist offenders, who have unique risk and etiological factors including childhood sexual abuse/maltreatment and atypical sexual interests. Conclusions: A clear distinction has been shown between generalist ASOs and specialist ASOs. Assessment measures and treatment targets geared toward one of these groups may be less effective with the other group, which means that this distinction is clinically important. It is expected that if treatment is matched to ASO type, sexual and nonsexual recidivism will be reduced and positive changes in other clinically important areas will be evident. © 2012 Elsevier Ltd.
Blais A.,University of Ottawa
Journal of Molecular Biology | Year: 2015
Skeletal myogenesis is the process of formation of the muscles that enable movement and breathing. Muscles form after the fate determination and differentiation of precursor cells. Being an extraordinarily complex process, myogenesis is regulated at multiple levels, and transcriptional regulation naturally plays a big part in the making of muscle. A significant part of what we know today of the transcriptional regulatory networks overseeing myogenesis comes from large-scale functional genomics studies. The objective of this review is to provide an overview of the various genomics techniques that have been employed over the years to understand myogenic regulation, to give a sense of the degree of understanding they have provided us up to now, and to highlight the next challenges to be overcome. © 2015 Elsevier Ltd.All rights reserved.
White L.,University of Ottawa
Journal of Advanced Nursing | Year: 2014
Aim: To report an analysis of the concept of mindfulness. Background: Mindfulness is an emerging concept in health care that has significant implications for a variety of clinical populations. Nursing uses this concept in limited ways, and subsequently requires conceptual clarity to further identify its significance, use and applications in nursing. Design: Mindfulness was explored using Rodgers evolutionary method of concept analysis. Data Sources: For this analysis, a sample of 59 English theoretical and research-based articles from the Cumulative Index to Nursing and Allied Health Literature database were obtained. The search was conducted between all-inclusive years of the database, 1981-2012. Review Methods: Data were analysed with particular focus on the attributes, antecedents, consequences, references and related terms that arose in relation to mindfulness in the nursing literature. Results: The analysis found five intricately connected attributes: mindfulness is a transformative process where one develops an increasing ability to 'experience being present', with 'acceptance', 'attention' and 'awareness'. Antecedents, attributes and consequences appeared to inform and strengthen one another over time. Mindfulness is a significant concept for the discipline of nursing with practical applications for nurse well-being, the development and sustainability of therapeutic nursing qualities and holistic health promotion. Conclusion: It is imperative that nurse well-being and self-care become a more prominent focus in nursing research and education. Further development of the concept of mindfulness could support this focus, particularly through rigorous qualitative methodologies. © 2013 John Wiley & Sons Ltd.
McIntyre L.,University of Ottawa
Systematic reviews | Year: 2014
Acute respiratory distress syndrome (ARDS) in humans is caused by an unchecked proinflammatory response that results in diffuse and severe lung injury, and it is associated with a mortality rate of 35 to 45%. Mesenchymal stromal cells (MSCs; 'adult stem cells') could represent a promising new therapy for this syndrome, since preclinical evidence suggests that MSCs may ameliorate lung injury. Prior to a human clinical trial, our aim is to conduct a systematic review to compare the efficacy and safety of MSC therapy versus controls in preclinical models of acute lung injury that mimic some aspects of the human ARDS. We will include comparative preclinical studies (randomized and non-randomized) of acute lung injury in which MSCs were administered and outcomes compared to animals given a vehicle control. The primary outcome will be death. Secondary outcomes will include the four key features of preclinical acute lung injury as defined by the American Thoracic Society consensus conference (histologic evidence of lung injury, altered alveolar capillary barrier, lung inflammatory response, and physiological dysfunction) and pathogen clearance for acute lung injury models that are caused by infection. Electronic searches of MEDLINE, Embase, BIOSIS Previews, and Web of Science will be constructed and reviewed by the Peer Review of Electronic Search Strategies (PRESS) process. Search results will be screened independently and in duplicate. Data from eligible studies will be extracted, pooled, and analyzed using random effects models. Risk of bias will be assessed using the Cochrane risk of bias tool, and individual study reporting will be assessed according to the Animal Research: Reporting of In Vivo Experiments (ARRIVE) guidelines. The results of this systematic review will comprehensively summarize the safety and efficacy of MSC therapy in preclinical models of acute lung injury. Our results will help translational scientists and clinical trialists to determine whether sufficient evidence exists to perform a human clinical trial. These results may also guide future acute lung injury preclinical and clinical research.
Application of a Pattern-based Classification System for Invasive Endocervical Adenocarcinoma in Cervical Biopsy, Cone and Loop Electrosurgical Excision (LEEP) Material: Pattern on Cone and LEEP is predictive of Pattern in the Overall Tumor
Djordjevic B.,University of Ottawa
International Journal of Gynecological Pathology | Year: 2015
A pattern-based classification system has been recently proposed for invasive endocervical adenocarcinoma, which is predictive of the risk of nodal metastases. Identifying cases at risk of nodal involvement is most relevant at the time of biopsy and loop electrosurgical excision procedure (LEEP) to allow for optimal surgical planning, and, most importantly, consideration of lymphadenectomy. This study aims to determine the topography of patterns of stromal invasion in invasive endocervical adenocarcinoma with emphasis on patterns in biopsy, cone, and LEEP. Invasive pattern was assessed following the pattern-based classification (Patterns A, B, and C) in 47 invasive endocervical adenocarcinomas treated with hysterectomy or trachelectomy and correlated with pattern of invasion at the tumor surface (2 mm of tumor depth) and on preoperative biopsy and cone/LEEP. Patterns A, B, and C were present in 21.3%, 36.2%, and 42.5% of cases, respectively. Most pattern A cases were Stage IA (90%), whereas most Pattern B and C cases were Stage IB (76.5% and 80%, respectively). Horizontal spread was on average larger in Pattern C (24.1 mm) than in Patterns A and B (7.7 and 12.3 mm, respectively). Pattern at the tumor surface correlated with the overall pattern in 95.7% of cases. Concordance between patterns at cone/LEEP and hysterectomy was 92.8%; the only discrepant case was upgraded from Pattern A on LEEP to C on final excision. Agreement between patterns in biopsy and the overall tumor, however, was only 37.5%. In all discrepant cases, biopsy failed to reveal destructive invasion, which was evident on excision. All discrepant biopsies with pattern A showed glandular complexity resembling exophytic papillary growth but did not meet criteria for destructive invasion. On excision, marked gland confluence with papillary architecture was evident. We conclude that the pattern of invasion on cone/LEEP is a good predictor of pattern of invasion on hysterectomy, particularly if there is destructive invasion (B or C). Thus, pattern-based classification can be successfully applied in these samples to guide definitive surgical treatment. Prediction of the overall pattern based on biopsy material alone appears to be suboptimal. However, glandular confluence and complexity on biopsy, regardless of its size, appears to be associated with destructive invasion in the overall tumor. ©2015International Society of Gynecological Pathologists
Murray S.J.,Carleton University |
Holmes D.,University of Ottawa
Bioethics | Year: 2013
Working within the tradition of continental philosophy, this article argues in favour of a phenomenological understanding of language as a crucial component of bioethical inquiry. The authors challenge the 'commonsense' view of language, in which thinking appears as prior to speaking, and speech the straightforward vehicle of pre-existing thoughts. Drawing on Maurice Merleau-Ponty's (1908-1961) phenomenology of language, the authors claim that thinking takes place in and through the spoken word, in and through embodied language. This view resituates bioethics as a matter of bodies that speak. It also refigures the meaning of ethical self-reflexion, and in so doing offers an alternative view on reflexivity and critique. Referring to the Kantian critical tradition and its reception by Hannah Arendt and Michel Foucault, we advance a position we call 'critical ethical reflexivity'. We contend that Merleau-Ponty's phenomenology of language offers valuable insight into ethical reflexivity and subject formation. Moreover, his understanding of language may foster new qualitative empirical research in bioethics, lead to more nuanced methods for interpreting personal narratives, and promote critical self-reflexion as necessary for bioethical inquiry. © 2013 John Wiley & Sons Ltd.
Gilmour K.M.,University of Ottawa
Comparative Biochemistry and Physiology - A Molecular and Integrative Physiology | Year: 2010
In the years since Larimer and Schmidt-Nielsen published their examination of red blood cell (RBC) carbonic anhydrase (CA) activities as a function of body mass in mammals, our knowledge of CA has expanded dramatically. We are now aware of the diversity of CA isoforms and their implication in a wide array of physiological processes. The catalytic mechanism of CA has been described, and numerous compounds that function as activators or inhibitors of CA activity have been identified. CA is investigated as a diagnostic tumor marker, and CA inhibitors are used or emerging as clinical treatments for diseases as diverse as glaucoma, cancer and obesity. Yet despite the intensity of research effort over the last 50. years and the wealth of information that has accumulated, the questions asked by Larimer and Schmidt-Nielsen remain relevant today - we still have much to learn about the patterns and physiological significance of interspecific differences in CA expression and activity. © 2010 Elsevier Inc.
Zhang Z.,University of Ottawa |
Donaldson A.A.,Dalhousie University |
Ma X.,Northwest University, China
Biotechnology Advances | Year: 2012
Enzymatic hydrolysis of pre-treated lignocellulosic biomass is an ideal alternative to acid hydrolysis for bio-ethanol production, limited primarily by pre-treatment requirements and economic considerations arising from enzyme production costs and specific activities. The quest for cheaper and better enzymes has prompted years of bio-prospecting, strain optimization through genetic engineering, enzyme characterization for simple and complex lignocellulosic feedstock, and the development of pre-treatment strategies to mitigate inhibitory effects. The recent shift to systematic characterizations of de novo mixtures of purified proteins is a promising indicator of maturation within this field of study, facilitating progression towards feedstock assay-based rapid enzyme mixture optimization. It is imperative that international standards be developed to enable meaningful comparisons between these studies and the construction of a database of enzymatic activities and kinetics, aspects of which are explored here-in. Complementary efforts to improve the economic viability of enzymatic hydrolysis through process integration and reactor design are also considered, where membrane-confinement shows significant promise despite the associated technological challenges. Significant advancements in enzyme technology towards the economic conversion of lignocellulosic biomass should be expected within the next few years as systematic research in enzyme activities conforms to that of traditional reaction engineering. © 2012.
Khalifa T.,University of Waterloo |
Naik K.,University of Waterloo |
Nayak A.,University of Ottawa
IEEE Communications Surveys and Tutorials | Year: 2011
Utility companies (electricity, gas, and water suppliers), governments, and researchers have been urging to deploy communication-based systems to read meters, known as automatic meter reading (AMR). An AMR system is envisaged to bring on benefits to customers, utilities, and governments. The advantages include reducing peak demand for energy, supporting the time-of-use concept for billing, enabling customers to make informed decisions, and reducing the cost of meter reading, to name a few. A key element in an AMR system is communications between meters and utility servers. Though several communication technologies have been proposed and implemented at a small scale, with the wide proliferation of wireless communication, it is the right time to critique the old proposals and explore new possibilities for the next generation AMR. We provide a comprehensive review of the AMR technologies proposed so far. Next, we present how future AMRs will benefit from third generation (3G) communication systems, the DLMS/COSEM (Data Language Messaging Specification/Companion Specification for Energy Metering) standard and Internet Protocol-based SIP (Session Initiation Protocol) signaling at the application level. The DLMS/COSEM standard provides a framework for meters to report application data (i.e. meter readings) to a utility server in a reliable manner. The SIP protocol is envisaged to be used as the signaling protocol between application entities running on meters and servers. The DLMS/COSEM standard and the SIP protocol are expected to provide an application level communication abstraction to achieve reliability and scalability. Finally, we identify the challenges at the application level that need to be tackled. The challenges include handling failure, gathering meter data under different time constraints (ranging from real-time to delay-tolerance), disseminating (i.e., unicasting, multicasting, broadcasting, and geocasting) control data to the meters, and achieving secure communication. © 2011 IEEE.
McInnes M.D.F.,University of Ottawa |
McInnes M.D.F.,Ottawa Hospital Research Institute |
Bossuyt P.M.M.,University of Amsterdam
Radiology | Year: 2015
Systematic reviews of imaging research represent a tool to better understand test accuracy or the efficacy of interventions. Like any type of research, appropriate methods must be applied to optimize quality. The purpose of this review is to outline common pitfalls in performing systematic reviews of imaging research, with a focus on challenges particular to performing reviews of diagnostic accuracy studies. The following challenges are highlighted: posing relevant review questions, conducting comprehensive literature searches, assessing for bias in included studies, testing for heterogeneity and publication bias, pooling results across studies, and forming appropriate conclusions. By guiding authors on how to overcome these, the hope is that published reviews in imaging research will be of higher quality and have a positive impact on clinical practice. In addition, the review aims to educate readers of reviews so they become aware of crucial elements of systematic reviews that could bias review results. © RSNA, 2015.
Leenen F.H.H.,University of Ottawa
American Journal of Hypertension | Year: 2014
In the past 1-2 decades, it has become apparent that the brain reninangiotensin- aldosterone system (RAAS) plays a crucial role in the regulation of blood pressure (BP) by the circulating RAAS. In the brain, angiotensinergic sympatho-excitatory pathways do not contribute to acute, second-to-second regulation but play a major role in the more chronic regulation of the setpoint for sympathetic tone and BP. Increases in plasma angiotensin II (Ang II) or aldosterone and in cerebrospinal fluid [Na+] can directly activate these pathways and chronically further activate/maintain enhanced activity by a slow neuromodulatory pathway involving local aldosterone, mineralocorticoid receptors (MRs), epithelial sodium channels, and endogenous ouabain. Blockade of any step in this slow pathway prevents Ang II-, aldosterone-, or salt and renal injury-induced forms of hypertension. It appears that the renal and arterial actions of circulating aldosterone and Ang II act as amplifiers but are not sufficient to cause chronic hypertension if their central actions are prevented, except perhaps at high concentrations. From a clinical perspective, oral treatment with an angiotensin type 1 (AT1)-receptor blocker at high doses can cause central AT1-receptor blockade and, in humans, lower sympathetic nerve activity. Low doses of the MR blocker spironolactone appear sufficient to cause central MR blockade and a decrease in sympathetic nerve activity. Integrating the brain actions of the circulating RAAS with its direct renal and arterial actions provides a better framework to understand the role of the circulating RAAS in the pathophysiology of hypertension and heart failure and to direct therapeutic strategies. © American Journal of Hypertension, Ltd 2014.
Rakusan K.,University of Ottawa
Experimental and Clinical Cardiology | Year: 2010
The safe use of drugs during pregnancy depends on several factors including the time of application, the type of drug and its dose. In the present review, the effect of certain therapeutic drugs on pregnancy is first described using general principles, followed by a more focused discussion on the type of adverse effects related to specific cardiovascular drugs used during pregnancy. In particular, adverse events related to the use of antihypertensive and antiarrhythmic drugs and anticoagulants are described, followed by the characterization of congenital cardiovascular defects resulting from the use of various drugs during pregnancy. Finally, various methods used to obtain information on the topic are described, and the need for carefully designed clinical trials is stressed. ©2010 Pulsus Group Inc. All rights reserved.
Armitage D.,University of Waterloo |
Marschke M.,University of Ottawa
Environmental Science and Policy | Year: 2013
Our aim in this paper is to examine the future for small-scale fishers and fish producers in the rapidly changing Tam Giang Lagoon in central Vietnam. The analysis shows: (1) the multi-dimensional and linked social, ecological and economic challenges confronting lagoon resource users and government officials, including the possibility that important features of the ecological system have been significantly altered; and (2) the spatial and temporal variation in the lived experience and conditions facing lagoon resource users even in the context of one relatively-bounded physical system. In this context, policy and management interventions need to better reflect social and ecological variability, incorporate local perspectives about the future of small-scale fishing and small producer aquaculture, and acknowledge how individuals simultaneously produce, resist and adapt to change. Key policy responses include the adoption of an integrated fishery (fishing and aquaculture) and coastal systems perspective, clarifying security of access rights to aquatic resources, and building institutional conditions for greater collaboration and learning among resource users and decision makers. © 2013 Elsevier Ltd.
Malcolm J.,University of Ottawa
Diabetes/Metabolism Research and Reviews | Year: 2012
Gestational diabetes mellitus (GDM) is gaining in importance as a predictor of future health risks for women and their offspring. In women, it is associated with increased long-term risks of diabetes, metabolic syndrome and increased cardiovascular disorders. For offspring of mothers with GDM, risks of GDM include abnormal glucose tolerance, obesity and metabolic syndrome. This review presents the evidence for GDM as a predictor of long-term health risks for mothers and their offspring. We highlight GDM as an opportune time to screen for and possibly intervene to prevent adverse health outcomes for both women and their offspring. © 2012 John Wiley & Sons, Ltd.
Gagnon M.,University of Ottawa
Journal of the Association of Nurses in AIDS Care | Year: 2015
People living with HIV (PLWH) continue to endure stigma and discrimination in the context of health care. This paper presents the findings of a qualitative study designed to (a) describe stigmatizing and discriminatory practices in health care settings, and (b) explore both symbolic and structural stigma from the perspectives of PLWH. For the purpose of this qualitative study, 21 semi-structured in-depth interviews were conducted in the province of Quebec, Canada. The data were analyzed following the principles of thematic analysis. During analysis, three themes were identified, and relations between these themes were delineated to reflect the experiences of participants. The findings suggest that HIV-related stigma in health care settings is episodic in nature. The findings also suggest that HIV-related stigma is experienced through interactions with health care providers (symbolic stigma) and, finally, that it is applied systematically to manage risk in the context of health care (structural stigma). © 2015 Association of Nurses in AIDS Care.
Liu X.J.,Ottawa Hospital Research Institute |
Liu X.J.,University of Ottawa
Cytoskeleton | Year: 2012
Generation of a haploid female germ cell, the egg, consists of two rounds of asymmetric cell division (meiosis I and meiosis II), yielding two diminutive and nonviable polar bodies and a large haploid egg. Animal eggs are also unique in the lack of centrioles and therefore form meiotic spindles without the pre-existence of the two dominant microtubule organizing centers (centrosomes) found in mitosis. Meiotic spindle assembly is further complicated by the unique requirement of sister chromatid mono-oriented in meiosis I. Nonetheless, the eggs appear to adopt many of the same proteins and mechanisms described in mitosis, with necessary modifications to accommodate their special needs. Unraveling these special modifications will not only help understanding animal reproduction, but should also enhance our understanding of cell division in general. © 2012 Wiley Periodicals, Inc.
Dissou Y.,University of Ottawa
Energy Policy | Year: 2010
The recent uptrend in oil prices represents both an opportunity and a challenge for small-open developed and oil-exporting countries. Using Canada as a study case and in contrast to most studies that use aggregate models, this paper employs a multi-sector, intertemporal general equilibrium model to provide perspectives on the sectoral, aggregate and dynamic adjustments of a sustained increase in oil prices. It highlights the transmission channels through which the rise in oil prices affects the domestic economy. The simulation results suggest that the shock would have positive aggregate impacts, but would also spur the reallocation of resources and would therefore induce disparities in sectoral adjustments. The suggested contraction in some industries could not however be attributed to a pure Dutch disease phenomenon because of, among other factors, the cost-push effect induced by the increase in oil prices. © 2009 Elsevier Ltd. All rights reserved.
Keely E.,University of Ottawa
Diabetes/Metabolism Research and Reviews | Year: 2012
The ability to detect postpartum dysglycaemia, intervene and prevent type 2 diabetes in this high-risk population may be the most compelling reason to diagnose gestational diabetes. However, most studies show that less than 50% of women receive any glucose screening in the postpartum period and are thus denied this opportunity. Although many have advocated for simpler testing, the 75-g oral glucose tolerance test remains the gold standard as fasting glucose level will miss 30-40% of cases of type 2 diabetes and will not detect isolated impaired glucose tolerance. Haemoglobin A 1c as a screening test has not been adequately studied. To improve postpartum screening rates, we need to increase awareness of the very high risk of type 2 diabetes, improve communication between providers, reduce fragmentation of care and introduce system factors that facilitate screening adherence. © 2012 John Wiley & Sons, Ltd.
Roberts R.,University of Ottawa |
Roberts R.,Ruddy Canadian Cardiovascular Genetics Center
Trends in Cardiovascular Medicine | Year: 2015
CAD and cancer account for over one-half of all deaths in the world. It is claimed that the 21st century is the last century for CAD. This is, in part, because CAD is preventable based on randomized, placebo-controlled clinical trials, which show modifying known risk factors such as cholesterol is associated consistently with 40-60% reduction in morbidity and mortality from CAD. Comprehensive prevention will require modifying genetic risk factors that are claimed to account for 40-60% of predisposition to CAD. The 21st century is meeting this challenge with over 50 genetic risk variants discovered and replicated in large genome-wide association studies involving over 200,000 cases and controls. Similarly, 157 genetic variants have been discovered that regulate plasma lipids including, LDL-C, HDL-C, triglycerides, and total cholesterol. A major finding from these studies is that only 15 of the 50 genetic variants for CAD act through known risk factors. Hence, the pathogenesis of CAD in addition to cholesterol and other known risk factors is due to various other factors, many of which remain unknown. Secondly, genes regulating the plasma triglyceride levels are strongly associated with the pathogenesis of CAD. Thirdly, Mendelian randomization studies show no protection from genes that increase plasma HDL cholesterol. This is contrary to current opinion. These genetic risk variants have provided new targets for the development of novel therapies to prevent CAD. Already a new and potent drug has been developed targeting PCSK9, which is in phase 3 clinical trials and shows great efficacy and safety for prevention of CAD. The 21st century is looking very bright for the prevention of CAD. © 2015 Elsevier Inc.
Wang M.,Beijing Jiaotong University |
Yao J.,University of Ottawa
IEEE Photonics Technology Letters | Year: 2013
An optical vector network analyzer (OVNA) based on unbalanced double-sideband (UB-DSB) modulation with improved measurement accuracy is proposed and experimentally demonstrated. It is different from an OVNA based on optical single-sideband (OSSB) modulation in which one-to-one mapping between the optical and radio frequency responses is employed to measure the magnitude and phase responses of an optical component, the proposed technique measures the magnitude and phase responses by taking into consideration of the power of the other sideband through solving two equations that are associated with the UB-DSB modulation, thus the errors due to the residual power of the other sideband in an OSSB modulation based approach are completely eliminated. A mathematical model providing the transfer function of an optical component is derived. The measurement of a phase-shifted fiber Bragg grating and a linearly chirped fiber Bragg grating is performed. Comparing with the measured results based on OSSB modulation, obvious improvement in measurement accuracy is demonstrated. © 1989-2012 IEEE.
Vlassoff C.,University of Ottawa
Journal of Biosocial Science | Year: 2012
This paper compares the desired fertility of rural Indian women in 1987 with their actual fertility in 2007. Seventy-one respondents who stated definite fertility intentions and had fewer children than desired in 1987 were re-interviewed 20 years later, as part of a larger study. The results indicated that these women had fewer children than intended and stopped childbearing once they reached, or approximated, their desired number of sons. The majority had been sterilized, indicating broad acceptance of lower fertility among rural women and the success of India's family planning efforts, although the practice of sex determination seems also to have played a role. These findings echo those of an earlier longitudinal study of reproductive intentions and outcomes in the same community, demonstrating the persistence of son preference in determining reproductive behaviour, even in the context of low overall fertility. The paper concludes with a discussion of the policy and programme implications of the study's findings. © 2011 Cambridge University Press.
Collins J.J.P.,University of Ottawa |
Thebaud B.,Ottawa Hospital Research Institute
Antioxidants and Redox Signaling | Year: 2014
Significance: Bronchopulmonary dysplasia (BPD) is a disease of the developing lung that afflicts extreme preterm infants in the neonatal intensive care unit. Follow-up studies into adulthood show that BPD is not merely a problem of the neonatal period, as it also may predispose to early-onset emphysema and poor lung function in later life.Recent Advances: The increasing promise of bone marrow- or umbilical cord-derived mesenchymal stromal cells (MSCs) to repair neonatal and adult lung diseases may for the first time offer the chance to make substantial strides in improving the outcome of extreme premature infants at risk of developing BPD. As more knowledge has been obtained on MSCs over the past decades, it has become clear that each organ has its own reservoir of endogenous MSCs, including the lung.Critical Issues: We have only barely scratched the surface on what resident lung MSCs exactly are and what their role and function in lung development may be. Moreover, what happens to these putative repair cells in BPD when alveolar development goes awry and why do their counterparts from the bone marrow and umbilical cord succeed in restoring normal alveolar development when they themselves do not?Future Directions: Much work remains to be carried out to validate lung MSCs, but with the high potential of MSC-based treatment for BPD and other lung diseases, a thorough understanding of the endogenous lung MSC will be pivotal to get to the bottom of these diseases. © 2014 Mary Ann Liebert, Inc.
McDowell I.,University of Ottawa
Journal of Psychosomatic Research | Year: 2010
As people lead longer and generally healthier lives, aspirations and expectations of health care extend to include well-being and enhanced quality of life. Several measurement scales exist to evaluate how well health care reaches these goals. However, the definitions of well-being or quality of life remain open to considerable debate, which complicates the design, validation, and subsequent choice of an appropriate measurement. Objective: This article reviews nine measures of psychological well-being, tracing their origins in alternative conceptual approaches to defining well-being. It compares their psychometric properties and suggests how they may be used. Methods: The review covers the Life Satisfaction Index, the Bradburn Affect Balance Scale, single-item measures, the Philadelphia Morale scale, the General Well-Being Schedule, the Satisfaction With Life scale, the Positive and Negative Affect Scale, the World Health Organization 5-item well-being index, and the Ryff's scales of psychological well-being. Results: Scales range in size from a single item to 22; levels of reliability and validity range from good to excellent, although for some of the newer scales we lack information on some forms of validity. Conclusion: Measures exist to assess several conceptions of psychological well-being. Most instruments perform adequately for survey research, but we know less about their adequacy for use in evaluating health care interventions. There remains active debate over how adequately the questions included portray the theoretical definition of well-being on which they are based. © 2010 Elsevier Inc.
Audet P.,University of Ottawa
Geophysical Research Letters | Year: 2013
Identifying the sources of seismic anisotropy in subduction zone forearcs is key to understanding mantle deformation processes. Current models based on the interpretation of shear-wave splitting measurements favor the flowinduced alignment of olivine crystals around down-going slabs or the presence of foliated serpentine minerals due to subduction-related processes, thereby neglecting fossil slab fabric as a significant source of anisotropy. We use seismic receiver functions to show evidence for strong anisotropy within anhydrous uppermost mantle of subducting oceanic plates in the forearcs of Nankai, Cascadia, Mexico, and Costa Rica subduction zones. Seismic anisotropy models from the inversion of receiver function waveforms are consistent with fossil fabric generated at spreading ridges. © 2013. American Geophysical Union. All Rights Reserved.
Carlsen A.N.,University of Ottawa |
Maslovat D.,University of British Columbia |
Franks I.M.,University of British Columbia
Clinical Neurophysiology | Year: 2012
In this review we provide a summary of the observations made regarding advance preparation of the motor system when presenting a startling acoustic stimulus (SAS) during various movement tasks. The predominant finding from these studies is that if the participant is prepared to make a particular movement a SAS can act to directly and quickly trigger the prepared action. A similar effect has recently been shown in patients with Parkinson's disease. This " StartReact" effect has been shown to be a robust indicator of advance motor programming as it can involuntarily release whatever movement has been prepared. We review the historical origins of the StartReact effect and the experimental results detailing circumstances where advance preparation occurs, when it occurs, and how these processes change with practice for both healthy and clinical populations.Data from some of these startle experiments has called into question some of the previously held hypotheses and assumptions with respect to the nature of response preparation and initiation, and how the SAS results in early response expression. As such, a secondary focus is to review previous hypotheses and introduce an updated model of how the SAS may interact with response preparation and initiation channels from a neurophysiological perspective. © 2011 International Federation of Clinical Neurophysiology.
Audet P.,University of Ottawa
Physics of the Earth and Planetary Interiors | Year: 2014
The effective elastic thickness (T e) of the lithosphere controls the flexural response to transverse loading and can be used in conjunction with rheological models to remotely estimate surface heat flux of terrestrial planets. In the vast majority of studies, T e estimation is carried out in a two-step process: (1) the joint spectra (admittance and/or coherency) of gravity anomalies (free air and/or Bouguer) and topography are calculated within finite-size windows, and (2) the spectra are inverted using a model for the loading of an infinite elastic plate or shell. In recent years, research in the spatio-spectral analysis of Cartesian grids and improvements in lithospheric loading models have allowed the mapping of T e on the Earth at unprecedented resolution. Nevertheless, the limitations imposed by working with Cartesian data and models are hampering further advances in terrestrial T e studies. The planetary community, on the other hand, has traditionally used spatio-spectral methods that work directly on the sphere, thereby avoiding the undesirable distortions and biases inherent in Cartesian studies. However, the models and methods developed for the Earth have never been applied to planetary data, therefore also limiting further advances in the mapping of planetary T e. This paper reviews the latest developments in T e studies and proposes to combine advances in both terrestrial and planetary studies to allow the mapping of T e of terrestrial planets using a spherical wavelet analysis of gravity and topography data. We begin with a review of the recent literature on the challenges and debates concerning T e estimation from joint gravity and topography spectra. We then briefly review the implementation of the continuous planar and spherical wavelet transforms (CPWT and CSWT) and demonstrate that both transforms possess exactly the same resolving power, however the CSWT does not suffer from effects associated with non-periodic boundaries. We further re-derive, in a consistent manner, the expressions for the admittance and coherency from flexural equations for the loading of thin elastic plates and shells and show that they result in similar spectra, except at the longest wavelengths where the shell membrane stresses dominate. We then estimate global grids of Earth's continentalT e by inverting the planar and spherical admittance and coherency functions, both separately and jointly, using either free air or Bouguer gravity anomalies. The correspondence between the Cartesian and spherical approaches and the similarity of T e results for the Earth's continents indicate that the spherical methods are robust. Results obtained from the joint inversion of admittance and coherency show that simple lithospheric loading models fail to capture the complexity of the data, with adverse effects on the estimated parameters. Finally, we extend the analysis to the Moon and other terrestrial planets and discuss limitations and future applications of the fully spherical techniques. © 2013 Elsevier B.V.
Lagace T.A.,University of Ottawa
Current Opinion in Lipidology | Year: 2014
Purpose of review Proprotein convertase subtilisin/kexin type-9 (PCSK9) binds to LDL receptor (LDLR) and targets it for lysosomal degradation in cells. Decreased hepatic clearance of plasma LDL-cholesterol is the primary gauge of PCSK9 activity in humans; however, PCSK9's evolutionary role may extend to other lipoprotein classes and processes. This review highlights studies that are providing novel insights into physiological regulation of PCSK9 transcription and plasma PCSK9 activity. Recent findings Recent studies indicate that circulating PCSK9 binds to apolipoprotein B100 on LDL particles, which in turn inhibits PCSK9's ability to bind to cell surface LDLRs. Negative feedback of secreted PCSK9 activity by LDL could serve to increase plasma excursion of triglyceride-rich lipoproteins and monitor lipoprotein remodeling. Recent findings have identified hepatocyte nuclear factor-1a as a key transcriptional regulator that cooperates with sterol regulatory element-binding protein-2 to control PCSK9 expression in hepatocytes in response to nutritional and hormonal inputs, as well as acute inflammation. Summary PCSK9 is an established target for cholesterol-lowering therapies. Further study of PCSK9 regulatory mechanisms may identify additional control points for pharmacological inhibition of PCSK9-mediated LDLR degradation. PCSK9 function could reflect ancient roles in the fasting-feeding cycle and in linking lipoprotein metabolism with innate immunity. © 2014 Wolters Kluwer Health. Copyright © Lippincott Williams & Wilkins.
Moroz P.J.,University of Ottawa
Journal of orthopaedic trauma | Year: 2014
Road traffic crash-related death, injury, and chronic disability continue to be a major worldwide burden to drivers, pedestrians, and users of mass transit, especially in low- and middle-income countries (LMIC). Projections predict worsening of this burden, and while motorization of LMIC increases exponentially, a corresponding improvement in prehospital and acute in-hospital trauma care has not been seen. The WHO now has 2 programs that address different elements of this challenge, namely, the Violence and Injury Prevention department (prevention) and the Emergency and Essential Surgical Care project (treatment). Activities of Violence and Injury Prevention have included developing guidelines for prehospital and essential trauma care, whereas activities of the Emergency and Essential Surgical Care have included developing the Integrated Management of Emergency and Essential Surgical Care toolkit and a textbook, "Surgical Care at the District Hospital." Organized surgical institutions in high-income countries-trauma associations, university departments, surgical nongovernmental organizations, etc.-can benefit from the infrastructure and tools the WHO has developed to better address the deficits in surgical services to improve the equitable distribution of surgical care services and resources to LMIC.
Ernst R.E.,University of Ottawa |
Bell K.,Carleton University
Mineralogy and Petrology | Year: 2010
There is increasing evidence that many carbonatites are linked both spatially and temporally with large igneous provinces (LIPs), i. e. high volume, short duration, intraplate-type, magmatic events consisting mainly of flood basalts and their plumbing systems (of dykes, sills and layered intrusions). Examples of LIP-carbonatite associations include: i. the 66 Ma Deccan flood basalt province associated with the Amba Dongar, Sarnu-Dandali (Barmer), and Mundwara carbonatites and associated alkali rocks, ii. the 130 Ma Paraná-Etendeka (e. g. Jacupiranga, Messum); iii. the 250 Ma Siberian LIP that includes a major alkaline province, Maimecha-Kotui with numerous carbonatites, iv. the ca. 370 Ma Kola Alkaline Province coeval with basaltic magmatism widespread in parts of the East European craton, and v. the 615-555 Ma CIMP (Central Iapetus Magmatic Province) of eastern Laurentia and western Baltica. In the Superior craton, Canada, a number of carbonatites are associated with the 1114-1085 Ma Keweenawan LIP and some are coeval with the pan-Superior 1880 Ma mafic-ultramafic magmatism. In addition, the Phalaborwa and Shiel carbonatites are associated with the 2055 Ma Bushveld event of the Kaapvaal craton. The frequency of this LIP-carbonatite association suggests that LIPs and carbonatites might be considered as different evolutionary 'pathways' in a single magmatic process/system. The isotopic mantle components FOZO, HIMU, EM1 but not DMM, along with primitive noble gas signatures in some carbonatites, suggest a sub-lithospheric mantle source for carbonatites, consistent with a plume/asthenospheric upwelling origin proposed for many LIPs. © 2009 Springer-Verlag.
Yeung J.,University of Ottawa
Journal of otolaryngology - head & neck surgery = Le Journal d'oto-rhino-laryngologie et de chirurgie cervico-faciale | Year: 2013
The timely diagnosis of hearing loss in the pediatric population has significant implications for a child's development. However, audiological evaluation in this population poses unique challenges due to difficulties with patient cooperation. Though specialized adaptations exist (such as conditioned play audiometry), these methods can be time consuming and costly. The objective of this study was to validate an iPad-based play audiometer that addresses the shortcomings of existing audiometry. We designed a novel, interactive game for the Apple® iPad® that tests pure tone thresholds. In a prospective, randomized study, the efficacy of this tool was compared to standard play audiometry. 85 consecutive patients presenting to the Audiology Clinic at the Children's Hospital of Eastern Ontario (ages 3 and older) were recruited into this study. Their hearing was evaluated using both tablet and traditional play audiometry. Warble-tone thresholds obtained by both tablet and traditional audiometry. The majority of children in this age group were capable of completing an audiologic assessment using the tablet computer. The data demonstrate no statistically significant difference between warble-tone thresholds obtained by tablet and traditional audiometry (p=0.29). Moreover, the tablet audiometer demonstrates strong sensitivity (93.3%), specificity (94.5%) and negative predictive value (98.1%). The tablet audiometer is a valid and sensitive instrument for screening and assessment of warble-tone thresholds in children.
Aujnarain A.,University of Ottawa
Current gastroenterology reports | Year: 2013
The incidence of inflammatory bowel disease (IBD) is rising worldwide, with a particularly sharp increase in children. Rates are highest in North America and Europe, with rapid increases noted in developing nations adopting the Westernized environment. While many genetic risk loci have been identified that predispose people to IBD, incomplete penetrance and overlapping genotypes among patients with different phenotypes inadequately explain the etiology of these chronic diseases. Therefore, environmental risk factors have been the subject of much recent research. This article reviews the role of the environment in IBD, with particular focus on early-life exposures and pediatric-onset disease. The literature surrounding environmental risk factors is reviewed, including prenatal and perinatal exposures, the hygiene hypothesis, the urban environment, infection and antibiotic use, and secondhand tobacco smoke exposure. In addition, the possible role of the environment in altering the intestinal microbiome is addressed.
Meek M.E.B.,University of Ottawa
Toxicology | Year: 2013
More efficient methodology for assessing the impact of combined exposures to multiple chemicals has been considered in a project of the World Health Organization (WHO) International Programme on Chemical Safety (IPCS).Recommendations regarding terminology and the status of development of the framework, its content, review and application are described. Evolving experience in its application is illustrated by example (polybrominated diphenyls) with special emphasis on the critical content of problem formulation, the role of predictive tools in grouping of chemicals for consideration and the importance of explicit delineation of relative uncertainty and sensitivity for tiered assessment.Priorities in increasing the efficiency of risk assessment not only for combined exposures, but more generally based on experience acquired in developing the framework and its application in case studies are identified and recommendations included. © 2012 Elsevier Ireland Ltd.
Feng Z.,University of Science and Technology Beijing |
Liang M.,University of Ottawa
Journal of Sound and Vibration | Year: 2014
The vibration signals from complex structures such as wind turbine (WT) planetary gearboxes are intricate. Reliable analysis of such signals is the key to success in fault detection and diagnosis for complex structures. The recently proposed iterative atomic decomposition thresholding (IADT) method has shown to be effective in extracting true constituent components of complicated signals and in suppressing background noise interferences. In this study, such properties of the IADT are exploited to analyze and extract the target signal components from complex signals with a focus on WT planetary gearboxes under constant running conditions. Fault diagnosis for WT planetary gearboxes has been a very important yet challenging issue due to their harsh working conditions and complex structures. Planetary gearbox fault diagnosis relies on detecting the presence of gear characteristic frequencies or monitoring their magnitude changes. However, a planetary gearbox vibration signal is a mixture of multiple complex components due to the unique structure, complex kinetics and background noise. As such, the IADT is applied to enhance the gear characteristic frequencies of interest, and thereby diagnose gear faults. Considering the spectral properties of planetary gearbox vibration signals, we propose to use Fourier dictionary in the IADT so as to match the harmonic waves in frequency domain and pinpoint the gear fault characteristic frequency. To reduce computing time and better target at more relevant signal components, we also suggest a criterion to estimate the number of sparse components to be used by the IADT. The performance of the proposed approach in planetary gearbox fault diagnosis has been evaluated through analyzing the numerically simulated, lab experimental and on-site collected signals. The results show that both localized and distributed gear faults, both the sun and planet gear faults, can be diagnosed successfully. © 2014 Elsevier Ltd. All rights reserved.
Brosseau L.,University of Ottawa
Cochrane database of systematic reviews (Online) | Year: 2013
Therapeutic exercise is used as one modality to treat people with osteoarthritis (OA). To evaluate the effectiveness of therapeutic exercise of differing intensities on objective and subjective measures of disease activity in people with OA. We searched MEDLINE, EMBASE, Pedro, Current Contents, Sports Discus and CINAHL up to and including December 2002. The Cochrane Field of Rehabilitation and Related Therapies and the Cochrane Musculoskeletal Review Group were also contacted for a search of their specialized registers. Handsearching was conducted on all retrieved articles for additional studies. Comparative controlled studies, such as randomized controlled trials, controlled clinical trials, cohort studies or case/control studies, of therapeutic exercises compared to control or active interventions in people with OA were eligible. No language restrictions were applied. Abstracts were also accepted. Two independent reviewers identified potential articles from the literature search. These reviewers extracted data using pre-defined extraction forms. Consensus was reached on all data extraction. The two reviewers used a five point scale to assess the quality of the selected articles. Randomization, double-blinding and description of withdrawals were assessed. One study involving 39 participants met the inclusion criteria. The review indicates that there were no significant differences between high intensity and low intensity aerobic exercise on participants with OA of the knee for functional status, gait, pain and aerobic capacity (Mangione 1999). Both high intensity and low intensity aerobic exercise appear to be equally effective in improving a patient`s functional status, gait, pain and aerobic capacity for people with OA of the knee. Further research involving a greater number of subjects, and a larger number of studies involving a control group is needed to further substantiate these results.
Rock G.,University of Ottawa
Vox Sanguinis | Year: 2011
Introduction Current methods for pathogen inactivation of plasma involve four major processes using solvent-detergent (SD), methylene blue (MB), amotosalen and riboflavin as additives. Three of these methods involve the use of visible or ultraviolet light.Methods A comparison of the four methods was made using publications in Medline, Pubmed, Embase and Biosis to obtain data on the logistics of use, the quality of the plasma proteins and the effectiveness of pathogen inactivation.Results Three of the methods, MB, amotosalen and riboflavin, are designed for use in a blood bank; the SD method is generally applied at a centralized manufacturing centre and involves large plasma pools. All methods result in a reduction in protein values with the per cent retention of FVIII activity in the range of 67-78% and fibrinogen of 65-84%. Protein S and alpha 2-antiplasmin are lower following solvent-detergent treatment. Alterations in fibrinogen structure have been reported with methylene blue.Discussion Three of the methods are designed for small volume use in a blood bank. All four methods have some effect on the coagulant proteins; however, the final concentrations are within regulated limits. While there is variability in the effectiveness against pathogens, direct comparison is difficult because of the methodologies used. Nonetheless, all are effective in inactivating HIV and other lipid-enveloped pathogens. Clinical studies on the effectiveness of these products are surprisingly sparse, and no randomized clinical trials have yet been performed with amotosalen or riboflavin plasmas. © 2010 The Author(s). Vox Sanguinis © 2010 International Society of Blood Transfusion.
Djordjevic B.,University of Ottawa |
Malpica A.,University of Houston
American Journal of Surgical Pathology | Year: 2012
Serous tumor of low malignant potential (SLMP) and low-grade serous carcinoma (LGSC) are part of one biological continuum, whereby SLMP can transform into LGSC. It has been suggested that some nodal SLMPs arise from nodal endosalpingiosis and evolve independently in lymph nodes (rather than being related to the ovarian primary). In this article, we present the clinicopathologic features of 5 cases of nodal LGSC presenting in association with ovarian SLMP. Clinical information was obtained from the patients' charts. Pathologic features of the nodal LGSC, including lymph node location, size of and extent of involvement of tumor, architectural pattern, degree of cytologic atypia, mitotic index, and presence of psammoma bodies, were recorded. Ovarian SLMPs were noted for laterality, size, presence of surface excrescences, microinvasion, and micropapillary/cribriform pattern and for presence of autoimplants, invasive, and noninvasive implants. The distribution of any lymph nodes with nodal endosalpingiosis or SLMPs was also recorded. Patients ranged in age from 28 to 68 years (median, 32 y). In 4 cases, the diagnosis of nodal LGSC occurred at a different time from that of the ovarian SLMPs, ranging from 7 months before to 5 months after the ovarian tumor diagnosis. Nodal LGSC was detected in supraclavicular (2 cases), cervical, intramammary, and periaortic lymph nodes (1 case each). The gross lymph node size ranged from 0.9 to 2.5 cm (median, 1.3 cm). The tumors either replaced the entire lymph node or were found diffusely involving subcapsular and medullary sinuses or lymph node cortices. Tumor cells showed typical cytologic features of LGSC and no mitotic activity. In 2 cases, however, focal pleomorphic cells and 1 mitosis per 10 HPF were noted. Psammoma bodies were identified in all cases. When immunohistochemical analysis was performed, all tumors exhibited a profile in keeping with Müllerian origin. All ovarian tumors were well sampled and ranged in size from 0.1 to 13 cm (median, 2.5 cm). No ovarian SLMP tumors showed the micropapillary/cribriform pattern, whereas only focal microinvasion was detected in 3 cases. Four tumors had surface excrescences. All cases had noninvasive implants, and a single case also had invasive implants. Lymph node dissection was performed in 2 cases, revealing extensive endosalpingiosis in pelvic and periaortic lymph nodes and SLMP in pelvic lymph nodes. In 1 additional case, a single lymph node was sampled, revealing a nodal SLMP. Clinical follow-up ranged from 2 to 14 years (median, 9 y). All patients received postoperative chemotherapy. None of the patients experienced recurrence in pelvic or abdominal soft tissue. Two patients are free of disease. However, 2 patients, one with cervical and another with supraclavicular nodal LGSC, had recurrences at these sites and subsequently succumbed to metastatic disease. Both of these patients had pelvic and periaortic nodal SLMP and extensive nodal endosalpingiosis. Another patient, originally with supraclavicular LGSC, developed pelvic and abdominal lymphadenopathy, and is currently alive with disease. For the first time, we present a case series of patients with ovarian SLMP who, despite any evidence of LGSC in the pelvis or any pelvic recurrences, developed extrapelvic/extra-abdominal nodal LGSC. These patients also had endosalpingiosis and SLMP in pelvic and periaortic lymph nodes, suggesting that SLMP/LGSC tumors in lymph nodes may arise independently of the ovarian primary, progress along their own timeline, and undergo metastatic spread. Therefore, in patients with ovarian SLMP and extensive pelvic/periaortic nodal endosalpingiosis and/or SLMP, examination and follow-up of extrapelvic lymph nodes are warranted, even if the ovarian tumor lacks high-risk features of recurrence. © 2012 by Lippincott Williams & Wilkins.
Stahl M.,University of Ottawa
Frontiers in cellular and infection microbiology | Year: 2012
The gastrointestinal pathogen Campylobacter jejuni is able to colonize numerous different hosts and compete against the gut microbiota. To do this, it must be able to efficiently acquire sufficient nutrients from its environment to support its survival and rapid growth in the intestine. However, despite almost 50 years of research, many aspects as to how C. jejuni accomplishes this feat remain poorly understood. C. jejuni lacks many of the common metabolic pathways necessary for the use of glucose, galactose, or other carbohydrates upon which most other microbes thrive. It does however make efficient use of citric acid cycle intermediates and various amino acids. C. jejuni readily uses the amino acids aspartate, glutamate, serine, and proline, with certain strains also possessing additional pathways allowing for the use of glutamine and asparagine. More recent work has revealed that some C. jejuni strains can metabolize the sugar l-fucose. This finding has upset years of dogma that C. jejuni is an asaccharolytic organism. C. jejuni also possesses diverse mechanisms for the acquisition of various transition metals that are required for metabolic activities. In particular, iron acquisition is critical for the formation of iron-sulfur complexes. C. jejuni is also unique in possessing both molybdate and tungsten cofactored proteins and thus has an unusual regulatory scheme for these metals. Together these various metabolic and acquisition pathways help C. jejuni to compete and thrive in wide variety of hosts and environments.
Campbell K.,University of Ottawa
Noise and Health | Year: 2010
This article reviews event-related potentials (ERPs) the minute responses of the human brain that are elicited by external auditory stimuli and how the ERPs can be used to measure sleep disturbance. ERPs consist of a series of negative- and positive-going components. A negative component peaking at about 100 ms, N1, is thought to reflect the outcome of a transient detector system, activated by change in the transient energy in an acoustic stimulus. Its output and thus the amplitude of N1 increases as the intensity level of the stimulus is increased and when the rate of presentation is slowed. When the output reaches a certain critical level, operations of the central executive are interrupted and attention is switched to the auditory channel. This switching of attention is thought to be indexed by a later positivity, P3a, peaking between 250 and 300 ms. In order to sleep, consciousness for all but the most relevant of stimuli must be prevented. Thus, during sleep onset and definitive non-rapid eye movement (NREM) sleep, the amplitude of N1 diminishes to near-baseline level. The amplitude of P2, peaking from 180 to 200 ms, is however larger in NREM sleep than in wakefulness. P2 is thought to reflect an inhibitory process protecting sleep from irrelevant disturbance. As stimulus input becomes increasingly obtrusive, the amplitude of P2 also increases. With increasing obtrusiveness particularly when stimuli are presented slowly, a later large negativity, peaking at about 350 ms, N350, becomes apparent. N350 is unique to sleep, its amplitude also increasing as the stimulus becomes more obtrusive. Many authors postulate that when the N350 reaches a critical amplitude, a very large amplitude N550, a component of the K-Complex is elicited. The K-Complex can only be elicited during NREM sleep. The P2, N350 and N550 processes are thus conceived as sleep protective mechanisms, activated sequentially as the risk for disturbance increases. During REM sleep, the transient detector system again becomes somewhat activated, the amplitude of N1 reaching from 15 to 40% of its waking level. Very intense and/or very infrequently presented stimuli might elicit a P3-like deflection suggesting an intrusion into some aspect of consciousness. The types of experimental paradigms used in most ERP studies are quite different from those used in the study of noise and its effects on sleep. ERP studies will need to employ procedures that have greater ecological generalization; stimulus intensity needs to be lower, less abrupt, with much longer durations, and importantly, stimuli should be presented much less often.
Clouthier C.M.,University of Montreal |
Clouthier C.M.,A+ Network |
Clouthier C.M.,University of Ottawa |
Pelletier J.N.,University of Montreal |
And 2 more authors.
Chemical Society Reviews | Year: 2012
This critical review presents an introduction to biocatalysis for synthetic chemists. Advances in biocatalysis of the past 5 years illustrate the breadth of applications for these powerful and selective catalysts in conducting key reaction steps. Asymmetric synthesis of value-added targets and other reaction types are covered, with an emphasis on pharmaceutical intermediates and bulk chemicals. Resources of interest for the non-initiated are provided, including specialized websites and service providers to facilitate identification of suitable biocatalysts, as well as references to recent volumes and reviews for more detailed biocatalytic procedures. Challenges related to the application of biocatalysts are discussed, including how 'green' a biocatalytic reaction may be, and trends in biocatalyst improvement through enzyme engineering are presented (152 references). © 2012 The Royal Society of Chemistry.
Cluff T.,McMaster University |
Robertson D.G.E.,University of Ottawa
Gait and Posture | Year: 2011
This study examined lower extremity biomechanics during the initiation of stair descent from an upright, static posture. Seventeen healthy subjects (aged 23 ± 2.4 years) descended a five-step, steel-reinforced, wooden laboratory staircase (34° decline). Ten trials of stair descent were separated into two blocks of five trials. Beginning from an upright posture, subjects descended the staircase at their preferred velocity (0.53 ± 0.082. m/s) and continued the length of the laboratory walkway (∼4. m). Joint mechanics were contrasted between gait cycles. Relative to the initiation cycle at the top of the staircase, the dissipative knee extensor (K3) and hip flexor (H2) moments and powers were independent of progression velocity and approximated steady-state (i.e., constant) values after the first cycle of the trail limb (Step 5 to Step 3). In contrast, a salient relationship was observed between progression velocity and ankle joint mechanics at initial-contact. The plantiflexor moment, power and work at initial-contact (A1) increased with centre of mass velocity. Our results demonstrate that while the knee extensor moment is the primary dissipater of mechanical energy in stair descent, the ankle plantiflexors are the primary dissipaters associated with increased progression velocity. In addition, the results show that steady-state stair descent may not be attained during the first gait cycle of the trail limb. These data shed light on locomotive strategies used in stair descent and can be applied in biomechanical models of human stair gait. Researchers and practitioners should take into consideration the influence of gait cycle and progression velocity when evaluating lower extremity function in stair descent. © 2011 Elsevier B.V.
Cooper C.L.,University of Ottawa
Current Opinion in Infectious Diseases | Year: 2012
PURPOSE OF REVIEW: The 2009 pandemic HIN1 influenza strain (H1N12009) produced more severe disease and increased risk for mortality. As an at-risk population for more severe influenza illness, particular concern regarding HIV patients triggered a focused effort to evaluate disease burden and vaccine efficacy in these populations. RECENT FINDINGS: As with other immune-compromised individuals, most HIV-infected individuals recovered without major consequence. Although HIV infection was assumed to be a risk factor for more severe disease and death, the published literature does not indicate this to be so. Neuraminadase inhibitors were well tolerated by this population and there was no evidence of clinically significant pharmacokinetic interactions with antiretroviral therapy. Immunogenicity was increased with H1N12009 vaccine compared to the historical results of nonpandemic vaccines and optimized by the use of adjuvants. Booster dosing was also of benefit. H1N12009 vaccine was generally well tolerated without evidence of detrimental effect on HIV status. SUMMARY: The worse case scenario was not realized for H1N12009 in the general population or in those with HIV. Immunization with adjuvant represents a key measure to protect this population from H1N12009 and other future novel influenza strains. Copyright © Lippincott Williams & Wilkins.
Henriques D.Y.P.,York University |
Cressman E.K.,University of Ottawa
Journal of Motor Behavior | Year: 2012
Motor learning, in particular motor adaptation, is driven by information from multiple senses. For example, when arm control is faulty, vision, touch, and proprioception can all report on the arm's movements and help guide the adjustments necessary for correcting motor error. In recent years we have learned a lot about how the brain integrates information from multiple senses for the purpose of perception. However, less is known about how multisensory data guide motor learning. Most models of, and studies on, motor learning focus almost exclusively on the ensuing changes in motor performance without exploring the implications on sensory plasticity. Nor do they consider how discrepancies in sensory information (e.g., vision and proprioception) related to hand position may affect motor learning. Here, we discuss research from our lab and others that shows how motor learning paradigms affect proprioceptive estimates of hand position, and how even the mere discrepancy between visual and proprioceptive feedback can affect learning and plasticity. Our results suggest that sensorimotor learning mechanisms do not exclusively rely on motor plasticity and motor memory, and that sensory plasticity, in particular proprioceptive recalibration, plays a unique and important role in motor learning. © 2012 Taylor & Francis Group, LLC.
Zhu T.,Chongqing University |
He Q.,Chongqing University |
Xiao X.,Chongqing University |
Bao X.,University of Ottawa
Optics Express | Year: 2013
A distributed optical fiber sensing system merged Mach-Zehnder interferometer and phase sensitive optical time domain reflectometer (f-OTDR) system for vibration measurement with high-frequency response and high spatial resolution is demonstrated, where modulated pulses are proposed to be used as sensing source. Frequency response and location information are obtained by Mach-Zehnder interferometer and f-OTDR technology, respectively. In order to simulate high-frequency vibration of crack of cable and civil structure, experiments on detection of piezoelectric transducer and pencil-break are carried out. Spatial resolution of 5 m and the maximum frequency response of ∼3 MHz are achieved in 1064 m fiber link when the narrow pulse width is 50 ns. © 2013 Optical Society of America.
Welch V.,University of Ottawa
Cochrane database of systematic reviews (Online) | Year: 2010
Enhancing health equity has now achieved international political importance with endorsement from the World Health Assembly in 2009. The failure of systematic reviews to consider effects on health equity is cited by decision-makers as a limitation to their ability to inform policy and program decisions. To systematically review methods to assess effects on health equity in systematic reviews of effectiveness. We searched the following databases up to July 2 2010: MEDLINE, PsychINFO, the Cochrane Methodology Register, CINAHL, Education Resources Information Center, Education Abstracts, Criminal Justice Abstracts, Index to Legal Periodicals, PAIS International, Social Services Abstracts, Sociological Abstracts, Digital Dissertations and the Health Technology Assessment Database. We searched SCOPUS to identify articles that cited any of the included studies on October 7 2010. We included empirical studies of cohorts of systematic reviews that assessed methods for measuring effects on health inequalities. Data were extracted using a pre-tested form by two independent reviewers. Risk of bias was appraised for included studies according to the potential for bias in selection and detection of systematic reviews. Thirty-four methodological studies were included. The methods used by these included studies were: 1) Targeted approaches (n=22); 2) gap approaches (n=12) and gradient approach (n=1). Gender or sex was assessed in eight out of 34 studies, socioeconomic status in ten studies, race/ethnicity in seven studies, age in seven studies, low and middle income countries in 14 studies, and two studies assessed multiple factors across health inequity may exist.Only three studies provided a definition of health equity. Four methodological approaches to assessing effects on health equity were identified: 1) descriptive assessment of reporting and analysis in systematic reviews (all 34 studies used a type of descriptive method); 2) descriptive assessment of reporting and analysis in original trials (12/34 studies); 3) analytic approaches (10/34 studies); and 4) applicability assessment (11/34 studies). Both analytic and applicability approaches were not reported transparently nor in sufficient detail to judge their credibility. There is a need for improvement in conceptual clarity about the definition of health equity, describing sufficient detail about analytic approaches (including subgroup analyses) and transparent reporting of judgments required for applicability assessments in order to assess and report effects on health equity in systematic reviews.
Hemming K.,University of Birmingham |
Taljaard M.,Ottawa Hospital Research Institute |
Taljaard M.,University of Ottawa
Journal of Clinical Epidemiology | Year: 2016
Objectives To clarify and illustrate sample size calculations for the cross-sectional stepped wedge cluster randomized trial (SW-CRT) and to present a simple approach for comparing the efficiencies of competing designs within a unified framework. Study Design and Setting We summarize design effects for the SW-CRT, the parallel cluster randomized trial (CRT), and the parallel cluster randomized trial with before and after observations (CRT-BA), assuming cross-sectional samples are selected over time. We present new formulas that enable trialists to determine the required cluster size for a given number of clusters. We illustrate by example how to implement the presented design effects and give practical guidance on the design of stepped wedge studies. Results For a fixed total cluster size, the choice of study design that provides the greatest power depends on the intracluster correlation coefficient (ICC) and the cluster size. When the ICC is small, the CRT tends to be more efficient; when the ICC is large, the SW-CRT tends to be more efficient and can serve as an alternative design when the CRT is an infeasible design. Conclusion Our unified approach allows trialists to easily compare the efficiencies of three competing designs to inform the decision about the most efficient design in a given scenario. © 2016 The Authors. Published by Elsevier Inc.
Ahmed T.A.E.,Alexandria University |
Hincke M.T.,University of Ottawa
Histology and Histopathology | Year: 2014
Restoration of articular cartilage function and structure following pathological or traumatic damage is still considered a challenging problem in the orthopaedic field. Currently, tissue engineering-based reconstruction of articular cartilage is a feasible and continuously developing strategy to restore structure and function. Successful articular cartilage tissue engineering strategy relies largely on several essential components including cellular component, supporting 3D carrier scaffolding matrix, bioactive agents, proper physical stimulants, and safe gene delivery. Designing the right formulations from these components remain the main concern of the orthopaedic community. Utilization of mesenchymal stem cells (MSCs) for articular cartilage tissue engineering is continuously increasing compared to use of chondrocytes. Various sources of MSCs have been investigated including adipose tissue, amniotic fluid, blood, bone marrow, dermis, embryonic stem cells, infrapatellar fat pad, muscle, periosteum, placenta, synovium, trabecular bone, and umbilical cord. MSCs derived from bone marrow and umbilical cord are currently in different phases of clinical trials. A wide range of matrices have been investigated to develop tissue engineering - based strategies including carbohydrate-based scaffolds (agarose, alginate, chitosan/chitin, and hyaluronate), protein-based scaffolds (collagen, fibrin, and gelatin), and artificial polymers (polyglycolic acid, polylactic acid, poly(lactic lacticco- glycolic acid), polyethylene glycol, and polycaprolactone). Collagen - based scaffolds and photopolymerizable PEG - based scaffolds are currently in different phases of clinical trials. TGF-ß1, TGF-ß3, BMP-2, and hypoxic environment are the recommended bioactive agents to induce optimum chondrogenesis of MSCs, while TGF-ß1, TGF-ß3, SOX-9, BMP-2, and BMP-7 genes are the best candidate for gene delivery to MSCs. Electromagnetic field and the combination of shear forces/dynamic compression are the best maturation-promoting physical stimulants.
Zhou H.,University of Ottawa
Molecular & cellular proteomics : MCP | Year: 2011
Despite their importance in many biological processes, membrane proteins are underrepresented in proteomic analysis because of their poor solubility (hydrophobicity) and often low abundance. We describe a novel approach for the identification of plasma membrane proteins and intracellular microsomal proteins that combines membrane fractionation, a centrifugal proteomic reactor for streamlined protein extraction, protein digestion and fractionation by centrifugation, and high performance liquid chromatography-electrospray ionization-tandem MS. The performance of this approach was illustrated for the study of the proteome of ER and Golgi microsomal membranes in rat hepatic cells. The centrifugal proteomic reactor identified 945 plasma membrane proteins and 955 microsomal membrane proteins, of which 63 and 47% were predicted as bona fide membrane proteins, respectively. Among these proteins, >800 proteins were undetectable by the conventional in-gel digestion approach. The majority of the membrane proteins only identified by the centrifugal proteomic reactor were proteins with ≥ 2 transmembrane segments or proteins with high molecular mass (e.g. >150 kDa) and hydrophobicity. The improved proteomic reactor allowed the detection of a group of endocytic and/or signaling receptor proteins on the plasma membrane, as well as apolipoproteins and glycerolipid synthesis enzymes that play a role in the assembly and secretion of apolipoprotein B100-containing very low density lipoproteins. Thus, the centrifugal proteomic reactor offers a new analytical tool for structure and function studies of membrane proteins involved in lipid and lipoprotein metabolism.
Bourjeily G.,Brown University |
Paidas M.,Yale University |
Khalil H.,Brown University |
Rosene-Montella K.,Brown University |
Rodger M.,University of Ottawa
The Lancet | Year: 2010
Pulmonary embolism (PE) is the leading cause of maternal mortality in the developed world. Mortality from PE in pregnancy might be related to challenges in targeting the right population for prevention, ensuring that diagnosis is suspected and adequately investigated, and initiating timely and best possible treatment of this disease. Pregnancy is an example of Virchow's triad: hypercoagulability, venous stasis, and vascular damage; together these factors lead to an increased incidence of venous thromboembolism. This disorder is often suspected in pregnant women because some of the physiological changes of pregnancy mimic its signs and symptoms. Despite concerns for fetal teratogenicity and oncogenicity associated with diagnostic testing, and potential adverse effects of pharmacological treatment, an accurate diagnosis of PE and a timely therapeutic intervention are crucial. Appropriate prophylaxis should be weighed against the risk of complications and offered according to risk stratification. © 2010 Elsevier Ltd. All rights reserved.
Samaan N.,University of Ottawa
IEEE Transactions on Parallel and Distributed Systems | Year: 2014
This paper presents a novel economic model to regulate capacity sharing in a federation of hybrid cloud providers (CPs). The proposed work models the interactions among the CPs as a repeated game among selfish players that aim at maximizing their profit by selling their unused capacity in the spot market but are uncertain of future workload fluctuations. The proposed work first establishes that the uncertainty in future revenue can act as a participation incentive to sharing in the repeated game. We, then, demonstrate how an efficient sharing strategy can be obtained via solving a simple dynamic programming problem. The obtained strategy is a simple update rule that depends only on the current workloads and a single variable summarizing past interactions. In contrast to existing approaches, the model incorporates historical and expected future revenue as part of the virtual machine (VM) sharing decision. Moreover, these decisions are not enforced neither by a centralized broker nor by predefined agreements. Rather, the proposed model employs a simple grim trigger strategy where a CP is threatened by the elimination of future VM hosting by other CPs. Simulation results demonstrate the performance of the proposed model in terms of the increased profit and the reduction in the variance in the spot market VM availability and prices. © 2014 IEEE.
Audet P.,University of Ottawa
Journal of Geophysical Research B: Solid Earth | Year: 2015
The rheology of the Earth's crust controls the long-term and short-term strength and stability of plate boundary faults and depends on the architecture and physical properties of crustal materials. In this paper we examine the seismic structure and anisotropy of the crust around the San Andreas Fault (SAF) near Parkfield, California, using teleseismic receiver functions. These data indicate that the crust is characterized by spatially variable and strongly anisotropic upper and middle crustal layers, with a Moho at ∼35 km depth. The upper layer is ∼5-10 km thick and is characterized by strong (≥30%) anisotropy with a slow axis of hexagonal symmetry, where the plane of fast velocity has a strike parallel to that of the SAF and a dip of ∼40∼. We interpret this layer as pervasive fluid-filled microcracks within the brittle deformation regime. The ∼10-15 km thick midcrustal layer is also characterized by a weak axis of hexagonal symmetry with ≥20% anisotropy, but the dip direction of the plane of fast velocity is reversed. The midcrustal anisotropic layer is more prominent to the northeast of the San Andreas Fault. We interpret the mid crustal anisotropic layer as fossilized fabric within fluid-rich foliated mica schists. When combined with various other geophysical observations, our results suggest that fault creep behavior around Parkfield is favored by intrinsically weak and overpressured crustal fabric ©2015. American Geophysical Union. All Rights Reserved.
Gajewski K.,University of Ottawa
Global and Planetary Change | Year: 2015
Holocene temperature variations were reconstructed for the Canadian Arctic Archipelago and coastal Greenland using pollen data from 39 radiocarbon-dated lake sediment cores. Using the modern analog technique, mean July temperatures were estimated for the past 10.2. ka, and regional averages computed. In the western and central Arctic, maximum temperatures were found before 7. ka. In the eastern Canadian Arctic, north Greenland and east Greenland, maximum temperatures were found between 8 and 5. ka, and in southern Greenland after 4. ka. When combined with previously published reconstructions from boreal Canada and eastern Beringia, the Holocene climate history of this region can be divided into three parts with major transitions at 8.0 and 5.2. ka, however, the different regions had different histories. © 2015 The Author.
Stewart D.J.,University of Ottawa
Journal of the National Cancer Institute | Year: 2014
Wnt/β-catenin alterations are prominent in human malignancies. In non-small cell lung cancer (NSCLC), β-catenin and APC mutations are uncommon, but Wnt signaling is important in NSCLC cell lines, and Wnt inhibition reduces proliferation. Overexpression of Wnt-1,-2,-3, and-5a and of Wnt-pathway components Frizzled-8, Dishevelled, Porcupine, and TCF-4 is common in resected NSCLC and is associated with poor prognosis. Conversely, noncanonical Wnt-7a suppresses NSCLC development and is often downregulated. Although β-catenin is often expressed in NSCLCs, it was paradoxically associated with improved prognosis in some series, possibly because of E-cadherin interactions. Downregulation of Wnt inhibitors (eg, by hypermethylation) is common in NSCLC tumor cell lines and resected samples; may be associated with high stage, dedifferentiation, and poor prognosis; and has been reported for AXIN, sFRPs 1-5, WIF-1, Dkk-1, Dkk-3, HDPR1, RUNX3, APC, CDX2, DACT2, TMEM88, Chibby, NKD1, EMX2, ING4, and miR-487b. AXIN is also destabilized by tankyrases, and GSK3β may be inactivated through phosphorylation by EGFR. Preclinically, restoration of Wnt inhibitor function is associated with reduced Wnt signaling, decreased cell proliferation, and increased apoptosis. Wnt signaling may also augment resistance to cisplatin, docetaxel, and radiotherapy, and Wnt inhibitors may restore sensitivity. Overall, available data indicate that Wnt signaling substantially impacts NSCLC tumorigenesis, prognosis, and resistance to therapy, with loss of Wnt signaling inhibitors by promoter hypermethylation or other mechanisms appearing to be particularly important. Wnt pathway antagonists warrant exploration clinically in NSCLC. Agents blocking selected specific β-catenin interactions and approaches to increase expression of downregulated Wnt inhibitors may be of particular interest. © 2013 The Author.
Sleeman J.E.,University of St. Andrews |
Trinkle-Mulcahy L.,University of Ottawa
Current Opinion in Cell Biology | Year: 2014
Eukaryotic cells enclose their genome within a dedicated organelle, the nucleus, which is the site of major cellular events such as messenger RNA synthesis and processing, ribosome subunit biogenesis and DNA replication. Like the cytoplasm, the nucleus is compartmentalized to facilitate efficient coordination of these pathways, although subnuclear compartments form without the use of membranes. Numerous disease states have been linked to dysfunction of these compartments or 'nuclear bodies'. Recent advances have shed light on the formation and maintenance of key structures, including nucleoli, splicing speckles, paraspeckles, Cajal bodies, histone locus bodies and promyelocytic leukemia bodies. Here, we review the impact of these findings, which provide major insights into dynamic processes that affect both structure and function within the nucleus. © 2014 Elsevier Ltd.
Chan K.L.,University of Ottawa |
Teo K.,Hamilton HSC |
Dumesnil J.G.,Quebec Heart Institute |
Ni A.,Ottawa Hospital Research Institute |
Tam J.,St. Boniface Hospital
Circulation | Year: 2010
Background: Aortic stenosis (AS) is an active process with similarities to atherosclerosis. The objective of this study was to assess the effect of cholesterol lowering with rosuvastatin on the progression of AS. Methods and Results: This was a randomized, double-blind, placebo-controlled trial in asymptomatic patients with mild to moderate AS and no clinical indications for cholesterol lowering. The patients were randomized to receive either placebo or rosuvastatin 40 mg daily. A total of 269 patients were randomized: 134 patients to rosuvastatin 40 mg daily and 135 patients to placebo. Annual echocardiograms were performed to assess AS progression, which was the primary outcome; the median follow-up was 3.5 years. The peak AS gradient increased in patients receiving rosuvastatin from a baseline of 40.8±11.1 to 57.8±22.7 mm Hg at the end of follow-up and in patients with placebo from 41.6±10.9 mm Hg at baseline to 54.8±19.8 mm Hg at the end of follow-up. The annualized increase in the peak AS gradient was 6.3±6.9 mm Hg in the rosuvastatin group and 6.1±8.2 mm Hg in the placebo group (P=0.83). Treatment with rosuvastatin was not associated with a reduction in AS progression in any of the predefined subgroups. CONCLUSION-: Cholesterol lowering with rosuvastatin 40 mg did not reduce the progression of AS in patients with mild to moderate AS; thus, statins should not be used for the sole purpose of reducing the progression of AS. CLINICAL TRIAL REGISTRATION INFORMATION-: URL: http://www.controlled-trials.com/. Clinical trial registration number: ISRCTN 32424163. © 2010 American Heart Association. All rights reserved.
Boddy C.N.,University of Ottawa
Journal of Industrial Microbiology and Biotechnology | Year: 2014
Microbial natural products have played a key role in the development of clinical agents in nearly all therapeutic areas. Recent advances in genome sequencing have revealed that there is an incredible wealth of new polyketide and non-ribosomal peptide natural product diversity to be mined from genetic data. The diversity and complexity of polyketide and non-ribosomal peptide biosynthesis has required the development of unique bioinformatics tools to identify, annotate, and predict the structures of these natural products from their biosynthetic gene clusters. This review highlights and evaluates web-based bioinformatics tools currently available to the natural product community for genome mining to discover new polyketides and non-ribosomal peptides. © 2013 Society for Industrial Microbiology and Biotechnology.
Roberts R.,University of Ottawa
Circulation Research | Year: 2014
For a recent article in Science, Jiang et al1 used RNA inhibition to suppress specifically the expression of a mutant allele known to cause human familial hypertrophic cardiomyopathy. The RNA inhibition treatment prevented the development of familial hypertrophic cardiomyopathy in the mouse. This is an exciting, innovative finding which could pave the way for specific treatment of this disease in humans. If shown to be safe and effective, RNA inhibition could be applicable for many inherited autosomal dominant diseases. © 2014 American Heart Association, Inc.
Nikiforov G.B.,University of Ottawa |
Roesky H.W.,University of Gottingen |
Koley D.,Indian Institute of Science
Coordination Chemistry Reviews | Year: 2013
A significant amount of information regarding the synthesis, reactivity, and catalytic activity of titanium fluoride complexes is available in the literature. However, the reports are mostly nonsystematic and spread over a large number of specific journals. An attempt is made to collect and organize all available information. Emphasis is given on work published after 1990 with links to the previous reviews, but earlier work is also included if no systematic report was done before.Published synthetic methods to access titanium fluoride complexes are covered in the present review, as well as the properties and reactivity of titanium fluoride complexes. In particular, the behavior of TiF4 in non-aqueous solvents, as well as the interaction of TiF4 with neutral and charged ligands in non-aqueous solvents is reviewed. All published tetrafluoride complexes TiF4L2 (L - neutral ligand) are presented. Mixed chloro and fluoro titanium complexes supported by neutral ligands, their preparation, and isomerism are surveyed. DFT calculations were performed to estimate the relative basicities of molecular ligands in titanium fluoride complexes as well as the relative stability of fluoride bridged titanium complexes.The reactivity of heterometallic titanium-alkali metal, titanium-alkaline earth metal fluoride complexes, the interaction of titanium fluoride complexes with silicon substrates, and the reactivity of titanium complexes toward organofluorine compounds are presented later in the review.Titanium fluoride complexes have found numerous applications in organic synthesis, and in many cases, the fluoride complex shows better performance than do complexes supported by other types of ligands. Organotitanium fluoride complexes show antitumor activity, and their values of cytotoxicity are comparable to that of the "gold standard" cisplatin. © 2013 Elsevier B.V.
Rennie C.D.,University of Ottawa |
Church M.,University of British Columbia
Journal of Geophysical Research: Earth Surface | Year: 2010
Spatial distributions of depth-averaged water velocity, shear velocity, and apparent bed load velocity are mapped for the first time in a long reach of a wandering gravel bed river, lower Fraser River, British Columbia. Spatially intensive acoustic Doppler current profiler (aDcp) measurements were collected on the falling limbs of two freshets. Flow in the first year was near the threshold of motion, whereas in the second year discharge exceeded bankfull. Spatial distributions are interpolated from the point data using kriging. Joint density functions for shear velocity and flow depth throughout the reach are presented; marginal densities for shear velocity were near normally distributed but depth distributions were positively skewed by deep pools. The uncertainty of the spatial distributions is also assessed based on modeled temporal variability of the flow and bed load transport, measured aDcp error velocities, and calculated interpolation errors. The resulting maps are remarkably coherent, with maximum depth-averaged velocity, shear velocity, and apparent bed load velocity following the thalweg. Largest values occur in channel bends at zones of flow convergence where the thalweg flow accelerates toward the bank. However, in the lower flow year the highest apparent bed load velocity was observed outside the thalweg in a deep pool downstream of a rapidly eroding cut bank. Erosion at this site was related to a flow confluence with relatively low shear but highly turbulent, strongly three-dimensional separated flow. Copyright 2010 by the American Geophysical Union.
Tesfamariam S.,University of British Columbia |
Saatcioglu M.,University of Ottawa
Earthquake Spectra | Year: 2010
A reliable building vulnerability assessment is required for developing a risk-based assessment and retrofit prioritization. Tesfamariam and Saatcioglu (2008) proposed a simple building vulnerability module where the building performance modifiers are in congruence with FEMA 154. This paper is an extension of the building vulnerability assessment that include detailed performance modifier in congruence with FEMA 310 that is represented in a heuristic based hierarchical structure. Some of the input parameters are obtained through a walk down survey and are subject to vagueness uncertainty that is modelled through fuzzy set theory. A knowledge base fuzzy rule base modeling is developed and illustrated for reinforced concrete buildings damaged in the 1 May 2003 Bingöl, Turkey earthquake. © 2010, Earthquake Engineering Research Institute.
Menon K.,University of Ottawa
Pediatric critical care medicine : a journal of the Society of Critical Care Medicine and the World Federation of Pediatric Intensive and Critical Care Societies | Year: 2013
To systematically review randomized controlled trials (RCTs) of steroids conducted in children with fluid and/or vasoactive medication-dependent shock and evaluate and report on the quality and clinical and methodological heterogeneity of included trials. MEDLINE (1946 to January Week 2, 2012), Embase (1947-January 20, 2012), Cochrane Central Register of Controlled Trials (through January 2012), and reference lists of retrieved publications. No language restrictions were applied. We included only RCTs reporting on steroid use and clinical outcomes in pediatric shock. Study characteristics, interventions, and outcomes were retrieved by three independent reviewers. Pooled relative risks and 95% CIs were calculated using a random effects model. We identified 535 citations from which 13 full-text articles were retrieved for assessment. Eight articles evaluating a total of 447 children were selected for review. The median trial size was 67 patients (range, 28-98). Seven of the eight trials were published prior to 1996, and all trials were conducted in the developing world, and six of eight trials were in the setting of dengue shock. We found methodological issues related to allocation concealment, blinding and reporting of co-interventions, and outcome data among the included trials along with varying types, doses, timings, and duration of steroids making it difficult to compare outcomes. The overall meta-analysis showed no difference in mortality rates between those who did and did not receive steroids (relative risks, 0.744 [95% CI, 0.475-1.165]; p = 0.197). The literature on the use of steroids in pediatric shock is limited in amount and methodological quality and demonstrates conflicting results. The limited evidence on which current guidelines are based strongly supports the need for a well-designed, pragmatic randomized controlled trial on the use of steroids in pediatric shock to inform future guidelines.
Foshay N.,St. Francis Xavier University |
Kuziemsky C.,University of Ottawa
International Journal of Information Management | Year: 2014
As healthcare organizations continue to be asked to do more with less, access to information is essential for sound evidence-based decision making. Business intelligence (BI) systems are designed to deliver decision-support information and have been repeatedly shown to provide value to organizations. Many healthcare organizations have yet to implement BI systems and no existing research provides a healthcare-specific framework to guide implementation. To address this research gap, we employ a case study in a Canadian Health Authority in order to address three questions: (1) what are the most significant adverse impacts to the organization's decision processes and outcomes attributable to a lack of decision-support capabilities? (2) what are the root causes of these impacts, and what workarounds do they necessitate? and (3) in light of the issues identified, what are the key considerations for healthcare organizations in the early stages of BI implementation? Using the concept of co-agency as a guide we identified significant decision-related adverse impacts and their root causes. We found strong management support, the right skill sets and an information-oriented culture to be key implementation considerations. Our major contribution is a framework for defining and prioritizing decision-support information needs in the context of healthcare-specific processes. © 2013 Elsevier Ltd. All rights reserved.
Mah T.-F.,University of Ottawa
Future Microbiology | Year: 2012
Bacterial biofilms are the basis of many persistent diseases. The persistence of these infections is primarily attributed to the increased antibiotic resistance exhibited by the cells within the biofilms. This resistance is multifactorial; there are multiple mechanisms of resistance that act together in order to provide an increased overall level of resistance to the biofilm. These mechanisms are based on the function of wild-type genes and are not the result of mutations. This article reviews the known mechanisms of resistance, including the ability of the biofilm matrix to prevent antibiotics from reaching the cells and the function of individual genes that are preferentially expressed in biofilms. Evidence suggests that these mechanisms have been developed as a general stress response of biofilms that enables the cells in the biofilm to respond to all of the changes in the environment that they may encounter. © 2012 Future Medicine Ltd.
Terrion J.L.,University of Ottawa
Journal of Child and Adolescent Substance Abuse | Year: 2015
This theoretical article traces one of the pathways of adolescent substance abuse from its roots in insecure attachment in childhood through ineffective relational mental models, poor communication skills, peer rejection, and the formation of antisocial friendships that lead to delinquency and substance use disorder. The model suggests communication skills training as a mediator and a means to altering this trajectory through changes to internal working models about relationships and the building of healthy peer relationships and recovery capital. This model focuses on communication as central to this complex process. © 2015, Copyright Taylor & Francis Group, LLC.
Levac D.E.,University of Ottawa |
Miller P.A.,McMaster University
Physiotherapy Theory and Practice | Year: 2013
The Nintendo Wii is a popular virtual reality (VR) video gaming system in rehabilitation practice and research. As evidence emerges related to its effectiveness as a physical therapy training method, clinicians require information about the pragmatics of its use in practice. The purpose of this descriptive qualitative study is to explore observations and insights from a sample of physical therapists (PTs) working with children with acquired brain injury regarding practical implications of using the Wii as a physical therapy intervention. Six PTs employed at a children's rehabilitation center participated in semi-structured interviews, which were transcribed and analyzed using content analysis. Two themes summarize the practical implications of Wii use: 1) technology meets clinical practice; and 2) onus is on the therapist. Therapists described both beneficial and challenging implications arising from the intersection of technology and practice, and reported the personal commitment required to orient oneself to the gaming system and capably implement this intervention. Findings include issues that may be relevant to professional development in a broader rehabilitation context, including suggestions for the content of educational initiatives and the need for institutional support from managers in the form of physical resources for VR implementation. © 2013 Informa Healthcare USA, Inc.
Turksen K.,Ottawa Hospital Research Institute |
Turksen K.,University of Ottawa |
Troy T.-C.,Ottawa Hospital Research Institute
Biochimica et Biophysica Acta - Reviews on Cancer | Year: 2011
The tight junctions (TJs) of epithelia are responsible for regulating the "fence and gate" function of polarized epithelial cells. It is now well-established that dysregulation of these functions contributes to initiation and progression of cancer. Recently, it has become clear that the Claudins, members of a large family of 27 closely related transmembrane proteins, play a crucial role in formation, integrity and function of TJs, the epithelial permeability barrier and epithelial polarization. A growing body of data indicates that Claudin expression is altered in numerous epithelial cancers in a stage- and tumor-specific manner. While a single universal mechanism is still lacking, accumulating evidence supports a role for epigenetic regulation of Claudin expression in tumorgenesis, with concomitant alterations in barrier function. We review here new insights and challenges in understanding Claudin function in normal physiology and cancer. © 2011 Elsevier B.V.
de Bold A.J.,University of Ottawa
Canadian Journal of Physiology and Pharmacology | Year: 2011
The discovery of the natriuretic properties of atrial muscle extracts pointed to the existence of an endocrine function of the heart that is now known to be mediated by the polypeptide hormones atrial natriuretic factor (ANF) and brain natriuretic peptide (BNP). On the basis of such a finding, approximately 27 000 publications to date have described a wide variety of biological properties of the heart hormones as well as their application as therapeutic agents and biomarkers of cardiac disease. Stimulation of secretion of ANF and BNP from the atria is mediated through mechanisms involving G proteins of the G q or G o types. We showed that the latter type underlies the transduction of muscle stretch into stimulated secretion and that it is more highly abundant in atria than in ventricles. The Gα o-1 subunit appears to play a key role in the biogenesis of atrial granules and in the intracellular targeting of their contents. Protein interaction studies using a yeast two-hybrid approach showed interactions between Gα o-1, proANF, and the intermediate conductance, calcium-activated K + channel SK4. Pharmacological inhibition of this channel decreases ANF secretion. Unpublished studies using in vitro knockdowns suggest interdependency in granule protein expression levels. These studies suggest previously unknown mechanisms of intracellular targeting and secretion control of the heart hormones that may find an application in the therapeutic manipulation of circulating ANF and BNP.
El Emam K.,Ottawa Hospital Research Institute |
El Emam K.,University of Ottawa
Genome Medicine | Year: 2011
Electronic health records are increasingly being linked to DNA repositories and used as a source of clinical information for genomic research. Privacy legislation in many jurisdictions, and most research ethics boards, require that either personal health information is de-identified or that patient consent or authorization is sought before the data are disclosed for secondary purposes. Here, I discuss how de-identification has been applied in current genomic research projects. Recent metrics and methods that can be used to ensure that the risk of re-identification is low and that disclosures are compliant with privacy legislation and regulations (such as the Health Insurance Portability and Accountability Act Privacy Rule) are reviewed. Although these methods can protect against the known approaches for re-identification, residual risks and specific challenges for genomic research are also discussed. © 2011 BioMed Central Ltd.
Kenny G.P.,University of Ottawa |
Journeay W.S.,Dalhousie University
Frontiers in Bioscience | Year: 2010
Human thermoregulatory control during heat stress has been studied at rest, during exercise and more recently during exercise recovery. Heat balance in the body is maintained by changes in the rate of heat loss via adjustments in skin blood flow and sweating. Independent of thermal control, the actions of nonthermal factors have important consequences in the control of heat loss responses during and following exercise. While the effect of these nonthermal factors is largely considered to be an inhibitory or excitatory stimulus which displaces the set-point about which temperature is regulated, their effects on human thermoregulatory control are far reaching. Many factors can affect the relative contribution of thermal and nonthermal influences to heat balance including exercise intensity, hemodynamic status, and the level of hyperthermia imposed. This review will characterize the physiological responses associated with heat stress and discuss the thermal and nonthermal influences on sweating and skin blood flow in humans. Further, recent calorimetric evidence for the understanding of thermal and nonthermal contributions to human heat balance will also be discussed.
Brook R.D.,University of Michigan |
Kousha T.,University of Ottawa
American Journal of Hypertension | Year: 2015
Background: Ambient air pollutant exposures have been associated with a wide variety of cardiovascular events; however, few studies have evaluated their impact upon acute emergency department (ED) visits for hypertension. Methods: The purpose of this study was to examine the associations between ED visits for hypertension and ambient air pollution concentrations among 6,532 patients during the period of January 2010 to December 2011 in Edmonton and Calgary, Alberta, Canada. The associations were evaluated using a case-crossover design. Results: Odds ratios and their 95% confidence interval have been calculated for 1 unit increase in their interquartile range for lags (the time between air pollutant measurement and exposure-response) 0-8 days. During the cold season, statistically significant positive results were observed for SO2 among lag days 4-6 and 8 for females and lag days 5 and 6 for males. Moreover, statistically significant positive results were observed for NO2 on lag day 7 for females and for PM2.5 on lag days 5 and 7, for females and lag day 6 for males. During the warm season, statistically significant positive results were observed for O3 on lag days 3 and 4 and for SO2 on lag days 2 and 8 for females. Conclusions: These findings support the hypothesis that recent exposures to ambient levels of several air pollutants can be capable of elevating blood pressure to a clinically significant extent such that it leads to ED visits for hypertension. © 2015 American Journal of Hypertension, Ltd.
Gilmour K.M.,University of Ottawa
Respiratory Physiology and Neurobiology | Year: 2012
Carbonic anhydrase (CA) is a zinc metalloenzyme that catalyzes the reversible reactions of carbon dioxide and water: CO2+H2O↔H++HCO3 -. It has long been recognized that CA is abundant in the fish gill, with attention focused on the role of CA in catalyzing the hydration of CO2 to provide H+ and HCO3 - for the branchial ion transport processes that underlie systemic ionic and acid-base regulation. Recent work has explored the diversity of CA isoforms in the fish gill. By linking these isoforms to different cell types in the gill, and by exploiting the diversity of fish species available for study, this work is increasing our understanding of the many roles that CA plays in the fish gill. In particular, recent work has revealed that fish utilize more than one model of CO2 excretion, that to understand the role of CA and the gill in ionic regulation and acid-base balance means characterizing the transporter and CA complement of individual cell types, and that CA plays roles in branchial sensory mechanisms. The goal of this brief review is to summarize these new developments, while at the same time highlighting key areas in which further research is needed. © 2012 Elsevier B.V.
Dacosta C.J.B.,Rochester College |
Baenziger J.E.,University of Ottawa
Structure | Year: 2013
Pentameric ligand-gated ion channels (pLGICs) mediate fast synaptic communication by converting chemical signals into an electrical response. Recently solved agonist-bound and agonist-free structures greatly extend our understanding of these complex molecular machines. A key challenge to a full description of function, however, is the ability to unequivocally relate determined structures to the canonical resting, open, and desensitized states. Here, we review current understanding of pLGIC structure, with a focus on the conformational changes underlying channel gating. We compare available structural information and review the evidence supporting the assignment of each structure to a particular conformational state. We discuss multiple factors that may complicate the interpretation of crystal structures, highlighting the potential influence of lipids and detergents. We contend that further advances in the structural biology of pLGICs will require deeper insight into the nature of pLGIC-lipid interactions. © 2013 Elsevier Ltd. All rights reserved.
Lagace T.A.,University of Ottawa |
Ridgway N.D.,Dalhousie University
Biochimica et Biophysica Acta - Molecular Cell Research | Year: 2013
The endoplasmic reticulum (ER) is an interconnected network of tubular and planar membranes that supports the synthesis and export of proteins, carbohydrates and lipids. Phospholipids, in particular phosphatidylcholine (PC), are synthesized in the ER where they have essential functions including provision of membranes required for protein synthesis and export, cholesterol homeostasis, and triacylglycerol storage and secretion. Coordination of these biological processes is essential, as highlighted by findings that link phospholipid metabolism in the ER with perturbations in lipid storage/secretion and stress responses, ultimately contributing to obesity/diabetes, atherosclerosis and neurological disorders. Phospholipid synthesis is not uniformly distributed in the ER but is localized at membrane interfaces or contact zones with other organelles, and in dynamic, proliferating ER membranes. The topology of phospholipid synthesis is an important consideration when establishing the etiology of diseases that arise from ER dysfunction. This review will highlight our current understanding of the contribution of phospholipid synthesis to proper ER function, and how alterations contribute to aberrant stress responses and disease. This article is part of a Special Issue entitled: Functional and structural diversity of endoplasmic reticulum. © 2013 Elsevier B.V.
Thakor N.,Apoptosis Research Center |
Holcik M.,Apoptosis Research Center |
Holcik M.,University of Ottawa
Nucleic Acids Research | Year: 2012
Physiological and pathophysiological stress attenuates global translation via phosphorylation of eIF2α. This in turn leads to the reprogramming of gene expression that is required for adaptive stress response. One class of cellular messenger RNAs whose translation was reported to be insensitive to eIF2α phosphorylation-mediated repression of translation is that harboring an Internal Ribosome Entry Site (IRES). IRES-mediated translation of several apoptosis-regulating genes increases in response to hypoxia, serum deprivation or gamma irradiation and promotes tumor cell survival and chemoresistance. However, the molecular mechanism that allows IRES-mediated translation to continue in an eIF2α-independent manner is not known. Here we have used the X-chromosome linked Inhibitor of Apoptosis, XIAP, IRES to address this question. Using toeprinting assay, western blot analysis and polysomal profiling we show that the XIAP IRES supports cap-independent translation when eIF2α is phosphorylated both in vitro and in vivo. During normal growth condition eIF2α-dependent translation on the IRES is preferred. However, IRES-mediated translation switches to eIF5B-dependent mode when eIF2α is phosphorylated as a consequence of cellular stress. © The Author(s) 2011. Published by Oxford University Press.
Pohl D.,University of Ottawa |
Tenembaum S.,National Pediatric Hospital
Current Treatment Options in Neurology | Year: 2012
Acute disseminated encephalomyelitis (ADEM) is an inflammatory demyelinating disease, characterized by an acute onset of polyfocal central nervous system (CNS) deficits, including encephalopathy, demonstrating multifocal lesions on MRI. ADEM is typically a monophasic disorder, but recurrent and multiphasic courses have been described. Furthermore, an ADEM presentation has been reported in neuromyelitis optica (NMO) and multiple sclerosis (MS), particularly in younger children. CNS infections, other autoimmune diseases, and neurometabolic disorders may mimic ADEM at manifestation. There is no single test confirming the diagnosis of ADEM, and diagnosis is based upon a combination of clinical and radiologic features and exclusion of diseases that resemble ADEM. Therefore, a broad workup including infectious, immunologic, and metabolic tests, as well as a systematic follow-up including MRI, is indicated to establish an accurate diagnosis as a prerequisite for an optimized treatment approach. There is a lack of evidence-based, prospective clinical trial data for the management of ADEM. Empiric antibacterial and antiviral treatment is standard of care until an infectious disease process is ruled out. Based on the presumed autoimmune etiology of ADEM, the common treatment approach consists of intravenous methylprednisolone at a dosage of 20 to 30 mg/kg per day (maximum 1 g/day) for 3 to 5 days, followed by an oral corticosteroid taper of 4 to 6 weeks. In case of insufficient response or contraindications to corticosteroids, intravenous immunoglobulin G (IVIG) at a dosage of 2 g/kg divided over 2 to 5 days is a therapeutic option. For severe or life-threatening cases of ADEM, plasmapheresisshould be considered early in the disease course. Decompressive craniectomy has been reported as a life-saving measure for ADEM patients with intracranial hypertension. There is a lack of specific recommendations for the long-term management of recurrent and multiphasic ADEM. In children with relapsing demyelinating events, the diagnosis of a chronic autoimmune CNS disease like MS or NMO should be considered. © Springer Science+Business Media, LLC 2012.
Kilty S.,University of Ottawa
BMC Ear, Nose and Throat Disorders | Year: 2012
Acute bacterial rhinosinusitis (ABRS) and chronic rhinosinusitis (CRS) frequently present in clinical practice. Guidelines for management of these conditions have been published extensively in the past. However, a set of guidelines that addressed issues specific to the Canadian environment while offering clear guidance for first-line clinicians was needed, and resulted in the recent publication of Canadian clinical practice guidelines for ABRS and CRS. In addition to addressing issues specific to Canadian physicians, the presented guidelines are applicable internationally, and offer single algorithms for the diagnosis and management of ABRS and CRS, as well as expert opinion in areas that do not have an extensive evidence base. This commentary presents major points from the guidelines, as well as the intended impact of the guidelines on clinical practice. See guidelines at:. © 2012 Kilty; licensee BioMed Central Ltd.
Rayner K.J.,University of Ottawa |
Hennessy E.J.,New York University
Journal of Lipid Research | Year: 2013
The complexity of microRNA (miRNA)-mediated pathway control has burgeoned since the discovery that miRNAs are found in the extracellular space and constitute a form of cell-cell communication. miRNAs have been found in plasma, urine, and saliva and have recently been shown to be carried on lipoproteins. This has led to the proposal that circulating miRNAs may be useful biomarkers of various diseases, including cardiovascular disease, diabetes, and other forms of dysregulated metabolism. Although our understanding of the cellular machinery responsible for the secretion of miRNA is incomplete, it has been demonstrated that miRNAs are packaged into exosomes, microvesicles, and apoptotic bodies by a broad range of cell types. Intriguingly, a large portion of extracellular miRNA is found outside of any lipid-containing vesicle, and instead is associated with RNA binding proteins like argonautes 1 and 2, which may aid in their protection from abundant nucleases in the extracellular space. The excitement for miRNAs as biomarkers is mounting as more and more evidence supports that these noncoding RNAs are actively secreted from diseased tissues, possibly before the onset of overt disease. While caution should be taken in these early days, there is little doubt that extracellular miRNAs will hold tremendous potential as both diagnostic and therapeutic agents. Copyright © 2013 by the American Society for Biochemistry and Molecular Biology, Inc.
Armstrong L.L.,University of Ottawa
Psychology, Health and Medicine | Year: 2012
The purpose of this study was to develop and begin to validate a brief self-report measure, the checklist of risk behaviours for youth (CORBY). This 15-item measure was designed to assess, over a 30-day period, multiple youth risk behaviours associated with mental health and well-being concerns. Early research provides initial support for the reliability and validity of the CORBY, but further research is warranted. The present study is the first to describe a brief survey addressing multiple youth risk behaviours, examining both the severity of health risk and number of behaviours in which youth are engaged. Such a measure may have important implications for both research and clinical applications. © 2012 Copyright Taylor and Francis Group, LLC.
Marcoux A.M.,University of Ottawa
The Journal of the Acoustical Society of America | Year: 2012
A total of 237 students, 10 to 17 years of age, from 14 schools underwent hearing evaluations. Otoscopic examination, tympanometry and air-conduction pure tone audiometry was conducted at low (0.5, 1, 2 kHz) and high (4 and 8 kHz) frequencies. In all schools, hearing thresholds were measured with headphones in a portable audiometric booth. Socio-demographic information from students and their parents were collected using questionnaires. Overall, the prevalence of any hearing loss greater than 15 dB was 22.3% for low or high frequency pure tone averages. Self-reported symptoms of hearing loss, such as tinnitus, difficulty following a conversation with background noise, and having to turn up the TV/radio more than in the past, were associated with audiometric thresholds, most notably at 4 kHz. These study findings are among the first to provide a detailed characterization of hearing status in a sample of youth in a Canadian demographic.
Singh K.,Ottawa Hospital Research Institute |
Dilworth F.J.,Ottawa Hospital Research Institute |
Dilworth F.J.,University of Ottawa
FEBS Journal | Year: 2013
The muscle-specific basic helix-loop-helix proteins MyoD, Myf5, myogenin (Myog) and MRF4 constitute the myogenic regulatory factor (MRF) family of transcription factors that drive muscle gene expression during myogenesis. Having evolved from a single ancestral gene, the spatial and temporal specificity of expression for each family member has been used to define a hierarchical relationship between the four MRFs. Molecular characterization of two of the MRFs (MyoD and Myog) suggests an important distinction between these factors, whereby MyoD establishes an open chromatin structure at muscle-specific genes, whereas Myog drives high levels of transcription of genes within this open chromatin state. Furthermore, recent data have provided an additional distinction between MRF function with respect to cell cycle regulation. Indeed, MyoD has been shown to directly activate genes involved in cell cycle progression, leading to myoblast proliferation. In contrast, Myog has antiproliferative activity through the activation of genes that shut down the cell proliferation machinery, leading to cell cycle exit and myoblast differentiation. Although the transcriptional activities of MyoD and Myog synergize to drive muscle differentiation, it is the expression of Myog that sets in motion a gene expression program that constitutes a 'point of no return', leading to cell cycle exit. In this review, we compare and contrast the current literature with respect to MRF function, with a particular emphasis on the differential role of MRFs in modulating the cell cycle. Myogenic regulatory factors (MRFs - MyoD, Myf5, Myogenin, and MRF4) are key transcription factors that regulate gene expression that establish the skeletal muscle cell fate. Here, we discuss the current literature concerning the role of MRFs in modulating cell cycle progression, and define Myogenin expression as a "point of no return" for establishing permanent cell cycle exit during muscle differentiation. © 2013 The Authors Journal compilation © 2013 FEBS.
Alam M.Z.,University of Ottawa |
Albert J.,Carleton University
Journal of Lightwave Technology | Year: 2013
The dominant polarization properties of the cladding modes excited by tilted fiber Bragg gratings are investigated. Even in conventional cylindrically symmetric fibers, by orienting the input core mode polarization with respect to the tilt plane of the grating cladding modes with near complete radial or azimuthal polarization can be excited at well separated wavelengths, as confirmed by experiments. © 2013 IEEE.
Oren T.I.,University of Ottawa
Simulation | Year: 2012
The GEneral System Theory implementer (GEST) was the first system-theory-based simulation model specification language. Even though a commercial implementation of GEST was not realized, over the years interesting ideas emerged based on it. At the beginning of this sequence of developments was the realization of two types of discontinuity in the integration of piecewise continuous systems. Afterwards, concepts generalized from the discontinuity processing were applied: (a) to modeling as a model update, multimodels, model switching, DNA-based modeling, dynamic model coupling, and dynamic model composability; (b) to simulations as multisimulation; (c) to psychology as a personality update and dynamic personality in human behavior simulation; (d) to understanding as multiunderstanding, switchable understanding, and misunderstanding avoidance; and (e) to emotion understanding as multiunderstanding and switchable understanding for better emotional intelligence as they are applied to the emotions of self and others. Each one of these areas may be the basis for some advanced modeling and simulation methodologies. Even though references are given for them, the emphasis in this article is the applicability of the same two discontinuity concepts to many different areas. © 2012 The Society for Modeling and Simulation International.
Moore R.D.,University of Calgary |
Hill A.B.,University of Ottawa
Journal of Vascular Surgery | Year: 2010
A 72-year-old male presents with a large asymptomatic aneurysm of his left popliteal artery. He has a history of noninsulin dependent diabetes, hyptertension, and a prior history of a percutaneous intervention for a coronary artery stenosis. He is anatomically and physiologically a candidate for surgical or endovascular repair of his aneurysm. The following debate attempts to resolve whether open repair remains the gold standard for the treatment of popliteal artery aneurysms. © 2010 Society for Vascular Surgery.
Fagnou K.,University of Ottawa
Topics in current chemistry | Year: 2010
Azines, diazines or thiazole N-oxides are highly reactive substrates in palladium-catalyzed direct arylation reaction. For these reactions, the results are inconsistent with an SEAr reaction pathway and may best fit with a concerted metalation-deprotonation-like (CMD) mechanism.
Stanimirovic D.B.,NRC Institute for Biological Sciences |
Stanimirovic D.B.,University of Ottawa |
Friedman A.,Ben - Gurion University of the Negev
Journal of Cerebral Blood Flow and Metabolism | Year: 2012
Pathophysiology of the neurovascular unit (NVU) is commonly seen in neurological diseases. The typical features of NVU pathophysiology include tissue hypoxia, inflammatory and angiogenic activation, as well as initiation of complex molecular interactions between cellular (brain endothelial cells, astroctyes, pericytes, inflammatory cells, and neurons) and acellular (basal lamina) components of the NVU, jointly resulting in increased blood-brain barrier permeability, brain edema, neurovascular uncoupling, and neuronal dysfunction and damage. The evidence of important role of the brain vascular compartment in disease pathogenesis has elicited the debate whether the primary vascular events may be a cause of the neurological disease, as opposed to a mere participant recruited by a primary neuronal origin of pathology? Whereas some hereditary and acquired cerebral angiopathies could be considered a primary cause of neurological symptoms of the disease, the epidemiological studies showing a high degree of comorbidity among vascular disease and dementias, including Alzheimer's disease, as well as migraine and epilepsy, suggested that primary vascular pathology may be etiological factor causing neuronal dysfunction or degeneration in these diseases. This review focuses on recent hypotheses and evidence, suggesting that pathophysiology of the NVU may be initiating trigger for neuronal pathology and subsequent neurological manifestations of the disease. © 2012 ISCBFM All rights reserved.
Heintzman P.,University of Ottawa
Journal of Disability and Religion | Year: 2014
This article synthesizes empirical studies that explain the relationship between nature-based recreation and spirituality for persons with disabilities. In order to describe this relationship, a theoretical model, which includes the components of antecedent conditions, setting, and recreation, is developed. Antecedent conditions include history and current circumstances,motivation, sociodemographic characteristics, and spiritual tradition. Setting components include being in nature, being away to a different environment, and place processes. Recreation components include activity, free time, solitude, and group experiences. The article further explains how these conditions and componentsmay lead to outcomes of spiritual experiences, spiritual well-being, and leisure-spiritual coping. Leisure-spiritual coping, which is particularly relevant for persons who are experiencing stress, refers to spiritual coping that takes place within the context of a person’s leisure. This model illustrates the complexity of the nature-based recreation and spirituality relationship. Recommendations for future research and implications for practitioners who work with people who have disabilities are outlined. © 2014, Taylor & Francis Group, LLC.
Silverman M.,University of Ottawa
Journal of Aging Studies | Year: 2013
This article reports on findings from microethnographic research that examined the lived reality of women caregivers through detailed observation of their everyday, embodied experiences. The research, which was rooted in the trend in social gerontology to emphasize subjective experience, focused on five women who were providing care to an older adult with a chronic illness or impairment. Four of the five women were caring for a spouse; one was caring for a parent. Observing the women's daily realities revealed tensions and contradictions between their subjective lived experiences and the pressures of the system in which they were functioning. The data revealed a caregiver habitus characterized by the performance of emotional labor. Performance was visible through dissonance between the caregivers' verbal and nonverbal expressions, and pointed to a high degree of emotion and body management. The women consistently put aside their own needs, in what can be considered a divestment in health capital. There was also evidence of merging between the caregiver and care receiver, made visible through tandem movements. The findings lead to implications for practice and for future aging research, including the benefits of observation for enhancing understanding of clients' experiences. © 2013 Elsevier Inc.
Fennell C.T.,University of Ottawa |
Waxman S.R.,Northwestern University
Child Development | Year: 2010
Past research has uncovered a surprising paradox: Although 14-month-olds have exquisite phonetic discrimination skills (e.g., distinguishing [b] from [d]), they have difficulty using phonetic detail when mapping novel words to objects in laboratory tasks (confusing bin and din). While some have attributed infants' difficulty to immature word learning abilities, the hypothesis presented herein is that infants are powerful word learners and this apparent difficulty occurs only when the referential status of the novel word is unclear. Across 2 experiments, 14-month-old infants (N = 44) used phonetic detail to map novel words to objects when conditions were conducive to word-referent mapping (clear sentential contexts and word-referent training), thus revealing no fundamental discontinuity in its use from speech perception to word learning. © 2010 The Authors. Child Development © 2010 Society for Research in Child Development, Inc.
Nerenberg K.,University of Ottawa |
Daskalopoulou S.S.,McGill University |
Dasgupta K.,McGill University
Canadian Journal of Cardiology | Year: 2014
The occurrence of common pregnancy-related medical disorders identifies women at high risk of developing future vascular disease. Systematic reviews of cohort studies demonstrate that gestational diabetes confers a 7-fold risk increase for type 2 diabetes, and preeclampsia confers a 1.8-fold risk increase for type 2 diabetes and 3.4-fold risk increase for hypertension. Gestational diabetes and hypertensive disorders of pregnancy (HDP) increase the risk of premature vascular disease, but the 2-fold risk increase associated with preeclampsia is only partially explained by the development of traditional vascular risk factors. Despite the compelling evidence for gestational diabetes and HDP as vascular risk indicators, there are no published Canadian vascular prevention guidelines that recognize these postpartum women. In contrast, the 2011 American Heart Association guidelines on cardiovascular disease in women include gestational diabetes and HDP in their vascular risk assessment. Studies indicate that the importance surveillance of vascular risk factors in these women after pregnancy is underappreciated by the women themselves and their physicians. Although a prudent diet and physically active lifestyle were demonstrated to reduce diabetes risk in women with a gestational diabetes history in the American Diabetes Prevention Program trial, adoption of these health behaviours is low; qualitative studies confirm a need for tailored strategies that address barriers and provide social support. Further research is also needed on approaches to reduce vascular risk in women with a history of gestational diabetes and HDP. Otherwise, an early window of opportunity for chronic disease prevention in young, high-risk women will be missed. © 2014 Canadian Cardiovascular Society.
Coutinho T.,University of Ottawa
Canadian Journal of Cardiology | Year: 2014
The burden of cardiovascular disease (CVD) in women is increasing, and CVD presently kills more North American women than men, highlighting the need for sex-specific research aimed at disentangling the complex interactions between sex, aging, and cardiovascular health. In the past decade, arterial stiffness has emerged as an independent predictor of adverse cardiovascular events and mortality, and its noninvasive, safe evaluation makes it an attractive tool for a snapshot assessment of cardiovascular health. An increasing number of reports have documented greater aortic stiffness in older women than men, which appears to have close relationships with blood pressure control, diastolic dysfunction, impaired ventricular coupling, and left ventricular remodelling in women. Thus, arterial stiffness is thought to play a role in the female predominance of several diseases such as isolated systolic hypertension, refractory hypertension, heart failure with preserved ejection fraction, and paradoxical low-flow, low-gradient, normal ejection fraction severe aortic stenosis. Furthermore, greater arterial stiffness is a common characteristic of women who develop hypertensive complications of pregnancy. Thus, better understanding sex differences in arterial stiffness and aging might provide valuable insights into CVD in women, and help identify novel risk stratification tools and therapeutic targets. To this end, the present review aims at describing sex differences in arterial stiffness, exploring the potential role of sex hormones and menopause on arterial aging, and highlighting the role of arterial stiffness in specific CVDs that preferentially affect women. © 2014 Canadian Cardiovascular Society.
Nasr A.,University of Ottawa |
Langer J.C.,University of Toronto
Journal of Pediatric Surgery | Year: 2012
Background: It is not clear in the literature whether infants with a prenatal diagnosis of gastroschisis should be delivered in a perinatal center with level 3 neonatal intensive care unit (NICU) and surgical facilities (inborn) or if they could be safely delivered in a more local hospital and then transferred to a perinatal center (outborn). Our goal was to determine the impact of delivery site on outcomes for neonates diagnosed as having gastroschisis. Methods: Data were obtained from the Canadian Pediatric Surgery Network, covering the years 2005 to 2008 for 18 pediatric surgical centers. Inborn was defined as birth in a hospital with a NICU or connected to a NICU by a bridge or tunnel. Outborn was defined as requiring transfer by ambulance or flight. A P value less than.05 was considered significant. Results: Of 395 infants with prenatally diagnosed gastroschisis, 237 were inborn and 158 were outborn. Univariate analysis demonstrated no significant difference between groups with respect to gestational age, birth weight, days on total parenteral nutrition, or length of hospital stay. There was a significant difference with regard to Score for Neonatal Acute Physiology-Version II, complication rates, comorbidities, and age at final closure. Logistic regression showed that location of delivery was a significant independent predictor for incidence of complications, as were Score for Neonatal Acute Physiology-Version II, comorbidities, and presence of bowel atresia or necrosis. The odds ratio of developing a complication when outborn was 1.6 (P =.05). Conclusions: Delivery outside a perinatal center is a significant predictor of complications for infants born with gastroschisis. © 2012 Elsevier Inc.
Lacaze-Masmonteil T.,University of Ottawa
Paediatric Respiratory Reviews | Year: 2014
Bronchopulmonary dysplasia (BPD) is the most frequent long term sequelae in infants born at less than 29 weeks of gestational age (GA) and histological chorioamnionitis (CA) is the most frequent condition associated with very preterm birth. Numerous studies have explored the association between BPD and CA with conflicting results. This inconsistency may be attributable to differences in populations, definitions, methods, and whether potential confounding factors such as GA, antenatal steroids, and post natal events were considered. A recent systematic review and meta-analysis shows some evidence of an association between BPD and CA; however, results adjusting for important confounders show more conservative measures of association. In addition, there was evidence of publication bias: when controlling for publication bias the results were more conservative and adjusted results were no longer significant. Recent large cohort studies not included in the systematic review do not support the belief that CA is associated with an increased risk of BPD. Despite a large body of evidence, CA cannot be definitively considered a risk factor for BPD. © 2013 Elsevier Ltd.
Jacob J.D.,University of Ottawa
Journal of Correctional Health Care | Year: 2014
The objective of this article is to examine the tensions that exist between care and custody in correctional environments by presenting the (im)possibilities of psychiatric nursing practice within this context. The analysis will be guided by empirical data obtained from a qualitative research conducted in a correctional setting. Semistructured interviews with nurses were conducted and used as the primary source of data for analysis. This article will explore the contextual characteristics of psychiatric nursing practice in correctional settings, describe the alienating effects of this context on nursing practice, theorize nurses' experience using Festinger's theory on cognitive dissonance, and, finally, explore how some nurses engage in the reconstruction of their care to counter the effects of working in correctional settings. © The Author(s) 2013.
Nicholls S.G.,University of Ottawa
Genome / National Research Council Canada = Génome / Conseil national de recherches Canada | Year: 2013
Including low penetrance genomic variants in population-based screening might enable personalization of screening intensity and follow up. The application of genomics in this way requires formal evaluation. Even if clinically beneficial, uptake would still depend on the attitudes of target populations. We developed a deliberative workshop on two hypothetical applications (in colorectal cancer and newborn screening) in which we applied stepped, neutrally-framed, information sets. Data were collected using nonparticipant observation, free-text comments by individual participants, and a structured survey. Qualitative data were transcribed and analyzed using thematic content analysis. Eight workshops were conducted with 170 individuals (120 colorectal cancer screening and 50 newborn screening for type 1 diabetes). The use of information sets promoted informed deliberation. In both contexts, attitudes appeared to be heavily informed by assessments of the likely validity of the test results and its personal and health care utility. Perceived benefits included the potential for early intervention, prevention, and closer monitoring while concerns related to costs, education needs regarding the probabilistic nature of risk, the potential for worry, and control of access to personal genomic information. Differences between the colorectal cancer and newborn screening groups appeared to reflect different assessments of potential personal utility, particularly regarding prevention.
Chernyak N.,University of Illinois at Chicago |
Gorelsky S.I.,University of Ottawa |
Gevorgyan V.,University of Illinois at Chicago
Angewandte Chemie - International Edition | Year: 2011
Dig this: 5-exo-dig carbocyclization of 1 into 2 features intramolecular carbopalladation of alkyne with Pd enolate (see scheme). DFT calculations show that the key Pd enolate forms by deprotonation assisted byb PdII acetate. Subsequent intramolecular alkyne carbopalladation, Z-E isomerization of the formed vinyl palladium species, and protiodepalladation leads to E-alkylidene indanones. (Chemical Equation Presented). © 2011 Wiley-VCH Verlag GmbH & Co. KGaA.
Van Walraven C.,Ottawa Hospital Research Institute |
Van Walraven C.,University of Ottawa |
Austin P.,University of Toronto
Journal of Clinical Epidemiology | Year: 2012
Objective: The provision of health care frequently creates digitized data - such as physician service claims, medication prescription records, and hospitalization abstracts - that can be used to conduct studies termed "administrative database research." While most guidelines for assessing the validity of observational studies apply to administrative database research, the unique data source and analytical opportunities for these studies create risks that can make them uninterpretable or bias their results. Study Design: Nonsystematic review. Results: The risks of uninterpretable or biased results can be minimized by; providing a robust description of the data tables used, focusing on both why and how they were created; measuring and reporting the accuracy of diagnostic and procedural codes used; distinguishing between clinical significance and statistical significance; properly accounting for any time-dependent nature of variables; and analyzing clustered data properly to explore its influence on study outcomes. Conclusion: This article reviewed these five issues as they pertain to administrative database research to help maximize the utility of these studies for both readers and writers. © 2012 Elsevier Inc. All rights reserved.
Anne-Gaelle R.-L.,University of Ottawa
Plant Physiology | Year: 2012
Growth patterns vary in space and time as an organ develops, leading to shape and size changes. Quantifying spatiotemporal variations in organ growth throughout development is therefore crucial to understand how organ shape is controlled. We present a novel method and computational tools to quantify spatial patterns of growth from three-dimensional data at the adaxial surface of leaves. Growth patterns are first calculated by semiautomatically tracking microscopic fluorescent particles applied to the leaf surface. Results from multiple leaf samples are then combined to generate mean maps of various growth descriptors, including relative growth, directionality, and anisotropy. The method was applied to the first rosette leaf of Arabidopsis (Arabidopsis thaliana) and revealed clear spatiotemporal patterns, which can be interpreted in terms of gradients in concentrations of growth-regulating substances. As surface growth is tracked in three dimensions, the method is applicable to young leaves as they first emerge and to nonflat leaves. The semiautomated software tools developed allow for a high throughput of data, and the algorithms for generating mean maps of growth open the way for standardized comparative analyses of growth patterns. © 2012 American Society of Plant Biologists. All Rights Reserved.
Roberts R.,University of Ottawa |
Stewart A.F.R.,Ruddy Canadian Cardiovascular Genetics Center
Current Opinion in Cardiology | Year: 2012
Purpose of Review: Prevention of coronary artery disease (CAD) is an appropriate goal for the 21st century. Randomized clinical studies consistently show a 30-40% reduction in mortality and morbidity by modifying known risk factors. However, genetic risk, estimated to account for 40-60% of susceptibility to CAD, has until recently been unknown. Comprehensive prevention will require knowledge of both. Recent Findings: The 21st century technology has responded to the challenge. Whereas the first genetic risk variant was not discovered until 2007 (9p21), a total of 36 genetic risk factors for CAD have been discovered and verified in large sample sizes. A startling discovery was that over two-thirds of these factors do not act through known risk factors or mechanisms. This obviously has great implications for the pathogenesis of CAD and presents many potential targets for new therapy. These genetic risk factors occur more commonly in the population than expected, with over half of them occurring in more than 50% of the population, and 10 of them occurring in at least 75% of the population. Summary: The role of genetic risk factors in genetic screening for prevention of heart disease is yet to be defined. The technology is already available, but functional analysis may be a prerequisite for their clinical application. © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins.
Kepron C.,University of Ottawa |
Pollanen M.S.,University of Toronto
Forensic Science, Medicine, and Pathology | Year: 2015
Purpose: The bone changes of vitamin D deficiency rickets have been invoked as an alternate explanation for child-abuse related fractures identified through medical imaging. The lack of modern histopathologic comparisons between these two entities limits the abilities of the forensic pathologist to address this differential diagnosis, both in their autopsy reports and on the witness stand. Methods: We report a comparison of the histologic appearance of the bones in a two year old child with vitamin D deficiency rickets with fractures occurring in three young children with child abuse. Results: In the case of rickets, there was marked architectural disorganization of endochondral ossification at the costochondral junctions and growth plates of long bones. The child abuse-related fractures showed osteochondral callus at different stages of healing, either centered on a discrete fracture line or at metaphyses (e.g. classical metaphyseal lesions). In many instances, the healing fractures disrupted the line of endochondral ossification. In none of the child abuse-related fractures was there any similarity to the histologic appearance of rickets. Conclusion: The maturation disturbance in the growth plate that occurs in rickets is a distinctive entity that cannot be confused histologically with healing fractures, including the classical metaphyseal lesion. © 2015, Springer Science+Business Media New York.
Plevin M.J.,CNRS Institute of Pharmacology and Structural Biology |
Bryce D.L.,University of Ottawa |
Boisbouvier J.,CNRS Institute of Pharmacology and Structural Biology
Nature Chemistry | Year: 2010
XH/π interactions make important contributions to biomolecular structure and function. These weakly polar interactions, involving π-system acceptor groups, are usually identified from the three-dimensional structures of proteins. Here, nuclear magnetic resonance spectroscopy has been used to directly detect methyl/π (Me/π) interactions in proteins at atomic resolution. Density functional theory calculations predict the existence of weak scalar (J) couplings between nuclei involved in Me/π interactions. Using an optimized isotope-labelling strategy, these J couplings have been detected in proteins using nuclear magnetic resonance spectroscopy. The resulting spectra provide direct experimental evidence of Me/π interactions in proteins and allow a simple and unambiguous assignment of donor and acceptor groups. The use of nuclear magnetic resonance spectroscopy is an elegant way to identify and experimentally characterize Me/π interactions in proteins without the need for arbitrary geometric descriptions or pre-existing three-dimensional structures. © 2010 Macmillan Publishers Limited. All rights reserved.
Sheshpari M.,University of Ottawa
Electronic Journal of Geotechnical Engineering | Year: 2015
Mining industry is always developing because of need for raw minerals to produce tools and material for human daily life. Underground mines are increasing in number, and older ones are targeting deeper levels for economic minerals. Safety requirement for working environment in underground and environmental policies prompted mining companies use mine wastes with different binders and methods to backfill created voids and stopes underground. Backfilling increases safety in underground for excavating remaining economic minerals, and going deeper and decreases environment pollution by dumping chemically toxic wastes underground. Cemented paste backfill (CPB) technology is one of the backfilling methods that use mine tailings, different binders and water to obtain durable and stiff materials for filling stopes. Different internal and external factors can impact CPB behavior and strength. In papers part I and II, some of influent factors on CPB strength and behavior are reviewed. In part I, binder type and ratio, water content and chemistry, and tailing fineness impact on CPB strength and behavior are discussed and reviewed. Some of conclusions that were implied in this part of paper can be described as follow. Increase of binder ratio in any water content and different tailing increases strength parameter of CPB. Higher water content than usual in any cement ratio and different tailing material reduces the strength of CPB. Sulphate content in pore water can cause sulphate attack in CPB and change CPB strength in different dosages, contrarily. Fine and coarse tailings and their percentage variation, significantly change CPB strength by different scenarios. © 2015 ejge.
Forrest J.R.,University of Ottawa
Current Opinion in Insect Science | Year: 2016
Insect phenologies are changing in response to climate warming. Shifts toward earlier seasonal activity are widespread; however, responses of insect phenology to warming are often more complex. Many species have prolonged their activity periods; others have shown delays. Furthermore, because of interspecific differences in temperature sensitivity, warming can increase or decrease synchronization between insects and their food plants and natural enemies. Here, I review recent findings in three areas — shifts in phenology, changes in voltinism, and altered species interactions — and highlight counterintuitive responses to warming caused by the particularities of insect life cycles. Throughout, I emphasize how an appreciation of the evolutionary processes shaping insect life histories is necessary to forecast changes in insect phenology and their demographic consequences. © 2016 Elsevier Inc.
Fahim A.,University of Ottawa
Journal of Medical Systems | Year: 2010
Respiratory sounds are of significance as they provide valuable information on the health of the respiratory system. Sounds emanating from the respiratory system are uneven, and vary significantly from one individual to another and for the same individual over time. In and of themselves they are not a direct proof of an ailment, but rather an inference that one exists. Auscultation diagnosis is an art/skill that is acquired and honed by practice; hence it is common to seek confirmation using invasive and potentially harmful imaging diagnosis techniques like X-rays. This research focuses on developing an automated auscultation diagnostic system that overcomes the limitations inherent in traditional auscultation techniques. The system uses a front end sound signal filtering module that uses adaptive Neural Networks (NN) noise cancellation to eliminate spurious sound signals like those from the heart, intestine, and ambient noise. To date, the core diagnosis module is capable of identifying lung sounds from non-lung sounds, normal lung sounds from abnormal ones, and identifying wheezes from crackles as indicators of different ailments. © 2009 Springer Science+Business Media, LLC.
Knoll G.A.,University of Ottawa |
Knoll G.A.,Ottawa Hospital Research Institute
American Journal of Kidney Diseases | Year: 2013
The end-stage renal disease population is aging. Nearly half of all new patients are older than 65 years and one third are older than 70 years. Assessing the possibility of transplantation for older patients with end-stage renal disease often involves contemplating more complex issues, including cognitive impairment, decreased functional status, and frailty, which makes selecting appropriate candidates more difficult. Older transplant recipients have decreased patient and transplant survival compared with younger recipients. For example, 75% of deceased donor transplant recipients aged 30-49 years are alive after 5 years compared to only 61% for those older than 65 years. Despite poorer outcomes compared with younger recipients, older transplant recipients have a significant improvement in survival compared with similar patients who remain on the wait list, with decreases in mortality of 41%-61% depending on the study. Use of living donors, even older living donors, provides significantly better outcomes for elderly recipients compared with the use of deceased donors. However, in the absence of a living donor, survival is improved significantly by accepting an expanded criteria donor organ rather than waiting for a standard criteria deceased donor. Older transplant recipients experience more infectious complications and less acute rejection, but the risk of transplant loss from rejection is increased compared with younger patients. These immunologic issues, along with the fact that older patients often are excluded from transplant trials, have made selecting an ideal immunosuppressive regimen challenging. Prospective comparative trials of different agents in the elderly population are warranted to better define the risk-benefit profile. This review discusses transplantation outcomes, including patient and transplant survival, different donor types, quality of life, and immunosuppression for older dialysis patients. © 2013 National Kidney Foundation, Inc.
Hamstra S.J.,University of Ottawa
Academic Emergency Medicine | Year: 2012
This article describes opportunities for scholarship in medical education, based on a brief overview of recent changes in medical education. The implications arising from these changes are discussed, with recommendations for focus, and suggestions and examples for making progress in this field. The author discusses 1) the historical context of the current shift toward competency-based medical education, 2) the potential contribution of social and behavioral sciences to medical education scholarship, 3) methods and approaches for supporting scholarship in medical education, and very briefly 4) trends in simulation. The author concludes with a call for quality in medical education scholarship and argues that the most promising and fruitful area of medical education scholarship for the future lies in the field of assessment of individual competence. © 2012 by the Society for Academic Emergency Medicine.
Labib M.A.,University of Ottawa
Neurosurgery | Year: 2016
BACKGROUND:: Subcortical injury resulting from conventional surgical management of intracranial hemorrhage may counteract the potential benefits of hematoma evacuation. OBJECTIVE:: To evaluate the safety and potential benefits of a novel, minimally invasive approach for clot evacuation in a multicenter study. METHODS:: The integrated approach incorporates 5 competencies: (1) image interpretation and trajectory planning, (2) dynamic navigation, (3) atraumatic access system (BrainPath, NICO Corp, Indianapolis, Indiana), (4) extracorporeal optics, and (5) automated atraumatic resection. Twelve neurosurgeons from 11 centers were trained to use this approach through a continuing medical education–accredited course. Demographical, clinical, and radiological data of patients treated over 2 years were analyzed retrospectively. RESULTS:: Thirty-nine consecutive patients were identified. The median Glasgow Coma Scale (GCS) score at presentation was 10 (range, 5-15). The thalamus/basal ganglion regions were involved in 46% of the cases. The median hematoma volume and depth were 36 mL (interquartile range [IQR], 27-65 mL) and 1.4 cm (IQR, 0.3-2.9 cm), respectively. The median time from ictus to surgery was 24.5 hours (IQR, 16-66 hours). The degree of hematoma evacuation was ≥90%, 75% to 89%, and 50% to 74% in 72%, 23%, and 5.0% of the patients, respectively. The median GCS score at discharge was 14 (range, 8-15). The improvement in GCS score was statistically significant (P < .001). Modified Rankin Scale data were available for 35 patients. Fifty-two percent of those patients had a modified Rankin Scale score of ≤2. There were no mortalities. CONCLUSION:: The approach was safely performed in all patients with a relatively high rate of clot evacuation and functional independence. ABBREVIATIONS:: AVM, arteriovenous malformationCLEAR II, Clot Lysis Evaluating Accelerated Resolution of IVH Phase IIDTI, diffusion tensor imagingGCS, Glasgow Coma ScaleICH, intracranial hemorrhageIQR, interquartile rangeIVH, intraventricular hemorrhageMIS, minimally invasive surgeryMISPACE, minimally invasive subcortical parafascicular access for clot evacuationMISTIE, Minimally Invasive Surgery and rt-PA in Intracerebral Hemorrhage EvacuationmRS, modified Rankin Scale Copyright © by the Congress of Neurological Surgeons
Hatcher S.,University of Ottawa |
Stubbersfield O.,University of Auckland
Canadian Journal of Psychiatry | Year: 2013
Objective: To systematically review the research on the association between sense of belonging and suicide. Method: We systematically reviewed electronic databases for studies that included assessments of suicidality and belonging. Results: We found 16 studies that met our eligibility criteria. They all found an association between belonging and suicidality but nearly all of the studies were in nonclinical populations, and the association was weak and could be taken into account by confounding factors. Conclusions: Low sense of belonging has a weak association with suicidality. However, current concepts make it hard to distinguish from loneliness or other measures of social support. An alternative view of belongingness, as a sense of connectedness to things other than people and in the past as well as the present, may generate alternative ideas about useful clinical interventions that may be especially relevant to indigenous populations.
Cavanagh M.F.,University of Ottawa
Journal of Documentation | Year: 2013
Purpose: In an increasingly competitive field of socially mediated information and knowledge available online, the public library's traditional services are increasingly questioned for relevancy. Drawing on the core premises of contemporary practice theory to ground the methodological and theoretical perspectives, the aim of this paper is to provide the initial "inside" view of traditional public library face-to-face reference work from a practice-based perspective. Design/methodology/approach: The paper includes an ethnographic case study of face-to-face reference service in four branches of one urban public library involving 170 hours of participant observation, 24 hours of unobtrusive observation, 480 reference interactions, and 28 participant interviews and analysis of policy documents. Findings: This analysis highlights the structuring and mediating role of objects in the enactment of reference work. A practice-based typology of reference interactions is introduced which characterizes the types of questions asked, knowledge processes in action, interpersonal communication style and mode of practice. The collective organizing actions of reference work are unpackaged in a non-hierarchical or flattened plane that recognizes the key actors and dynamics of the practice as it endures across time and space. Originality/value: Evidence and an approach are introduced to support re-conceptualizing public library reference work as an epistemic practice. © Emerald Group Publishing Limited.
Sattar S.A.,University of Ottawa
American Journal of Infection Control | Year: 2010
Hard, nonporous environmental surfaces in health care settings are now receiving due recognition for their role in the spread of several types of nosocomial pathogens. The corresponding increase in the means to decontaminate such surfaces to interrupt the spread of infections is leading to the marketing of a plethora of products and procedures, including the "green" variety, with varying claims of microbicidal activity, human and environmental safety, and materials compatibility. Limitations of the existing methods to assess environmental surface disinfectants and the regulations that govern their premarket registration make objective evaluations difficult. Label claims of many such products also do not reflect the realities of field use along with a strong tendency to focus on the "bug de jour." Furthermore, whereas wiping is often an integral part of environmental surface decontamination, products meant for the purpose are rarely assessed with the physical effect of wiping incorporated. Many "green" products possess neither the spectrum of microbicidal activity nor the speed of action essential for use in health care settings. In general, "self-sanitizing" surfaces being marketed actively these days require greater scrutiny for field-relevant microbicidal activity as well as the potential to enhance microbicide resistance. The widening use of environmental surface disinfectants is also raising concerns on their human and environmental safety at many levels along with the realization that routine surface disinfection procedures in health care settings are frequently inadequate and possibly counterproductive. All this points to an urgent review of the basic procedures for assessing existing and new environmental surface disinfectants for their microbicidal activity, label claims, registration requirements, overall safety, and routine practices of environmental surface decontamination. © 2010 Association for Professionals in Infection Control and Epidemiology, Inc.
McMurtry A.,University of Ottawa
Journal of Interprofessional Care | Year: 2010
This paper describes a collaborative action research project carried out by the author and the instructors of a large university-level interprofessional health team course. The research focused on introducing new complexity science-based ideas about collective learning to the course's pedagogy and curriculum, and tracking resultant changes in both thinking and practice. A number of insights emerged from the research, including a deeper understanding of collective learning in interprofessional contexts, a questioning of the meaning of consensus within teams, and the identification of a special role for trust in interprofessional relationships. One significant practical change in the course curriculum, which related to these insights, is also described. © 2010 Informa UK Ltd.
Loyka S.,University of Ottawa |
Charalambous C.D.,University of Cyprus
IEEE Transactions on Information Theory | Year: 2012
The compound capacity of uncertain multiple-input multiple-output channels is considered, when the channel is modeled by a class described by a (known) nominal channel and a constrained-norm (unknown) uncertainty. Within this framework, two types of classes are investigated with additive and multiplicative uncertainties subject to a spectral norm constraint, using the singular value decomposition and related singular value inequalities as the main tools. The compound capacity is a maxmin mutual information, representing the capacity of the class, in which the minimization is done over the class of channels while the maximization is done over the transmit covariance. Closed-form solutions for the compound capacity of the classes are obtained and several properties related to transmit and receive eigenvectors are presented. It is shown that, under certain conditions, the compound capacity of the class is equal to the worst-case channel capacity, thus establishing a saddle-point property. Explicit closed-form solutions are given for the worst-case channel uncertainty and the capacity-achieving transmit covariance matrix: the best transmission strategy achieving the compound capacity is a multiple beamforming on the nominal (known) channel eigenmodes with the beam power distribution via the water filling at a degraded SNR. As the uncertainty increases, fewer eigenmodes are used until only the strongest one remains active so that transmit beamforming is an optimal robust transmission strategy in this large-uncertainty regime, for which explicit conditions are given. Using these results, upper and lower bounds of the compound capacity are constructed for other bounded uncertainties and some generic properties are pointed out. The results are extended to compound multiple-access and broadcast channels. In all considered cases, the price to pay for channel uncertainty is an SNR loss (or, equivalently, the nominal channel degradation) commensurate with the uncertainty set radius measured by the spectral norm and the optimal signaling strategy is the transmission on the degraded nominal channel. © 2006 IEEE.
Piran S.,Toronto General Research Institute |
Liu P.,University of Ottawa |
Liu P.,11 Health |
Morales A.,University of Miami |
Hershberger R.E.,University of Miami
Journal of the American College of Cardiology | Year: 2012
This review provides the rationale for integrating genomic and protein biomarkers in the evolving diagnosis and management of dilated cardiomyopathy (DCM) and its causal pathway to heart failure (HF), with a larger objective to serve as a template for genomic and phenomic profiling of other cardiovascular disease. DCM is a major cause of HF and accounts for more than half of heart transplantation in adults and children worldwide. DCM may remain asymptomatic for years, but HF and/or arrhythmias, both late manifestations of the disease, ultimately cause significant morbidity and mortality. A significant proportion of DCM has a genetic etiology. DCM can also result from environmental injury such as infection, toxins, or catecholamine excess. While molecular genetic testing can identify those at risk for genetic DCM, epigenetic and sentinel phenomic staging can help to identify those at highest risk in need for intervention. Phenomic staging includes integrating clinical and imaging features, transcriptomics, higher order proteomics and metabolomics interactions, and epidemiological data. This principle can be applied in family members of patients with DCM, where genetic testing and clinical phenotyping are indicated. This will allow the design of specific interventions tailored to individuals sharing similar risks, to alter the natural history of DCM and obviate complications such as HF/arrhythmias. © 2012 American College of Cardiology Foundation.
Bickel D.R.,University of Ottawa
Statistical Applications in Genetics and Molecular Biology | Year: 2012
Problems involving thousands of null hypotheses have been addressed by estimating the local false discovery rate (LFDR). A previous LFDR approach to reporting point and interval estimates of an effect-size parameter uses an estimate of the prior distribution of the parameter conditional on the alternative hypothesis. That estimated prior is often unreliable, and yet strongly influences the posterior intervals and point estimates, causing the posterior intervals to differ from fixedparameter confidence intervals, even for arbitrarily small estimates of the LFDR. That influence of the estimated prior manifests the failure of the conditional posterior intervals, given the truth of the alternative hypothesis, to match the confidence intervals. Those problems are overcome by changing the posterior distribution conditional on the alternative hypothesis from a Bayesian posterior to a confidence posterior. Unlike the Bayesian posterior, the confidence posterior equates the posterior probability that the parameter lies in a fixed interval with the coverage rate of the coinciding confidence interval. The resulting confidence-Bayes hybrid posterior supplies interval and point estimates that shrink toward the null hypothesis value. The confidence intervals tend to be much shorter than their fixed-parameter counterparts, as illustrated with gene expression data. Simulations nonetheless confirm that the shrunken confidence intervals cover the parameter more frequently than stated. Generally applicable sufficient conditions for correct coverage are given. In addition to having those frequentist properties, the hybrid posterior can also be motivated from an objective Bayesian perspective by requiring coherence with some default prior conditional on the alternative hypothesis. That requirement generates a new class of approximate posteriors that supplement Bayes factors modified for improper priors and that dampen the influence of proper priors on the credibility intervals. While that class of posteriors intersects the class of confidence-Bayes posteriors, neither class is a subset of the other. In short, two first principles generate both classes of posteriors: a coherence principle and a relevance principle. The coherence principle requires that all effect size estimates comply with the same probability distribution. The relevance principle means effect size estimates given the truth of an alternative hypothesis cannot depend on whether that truth was known prior to observing the data or whether it was learned from the data. © 2012 De Gruyter. All rights reserved.
Florian Bentzinger C.,Ottawa Health Research Institute |
Wang Y.X.,Ottawa Health Research Institute |
Rudnicki M.A.,Ottawa Health Research Institute |
Rudnicki M.A.,University of Ottawa
Cold Spring Harbor Perspectives in Biology | Year: 2012
The genesis of skeletal muscle during embryonic development and postnatal life serves as a paradigm for stem and progenitor cell maintenance, lineage specification, and terminal differentiation. An elaborate interplay of extrinsic and intrinsic regulatory mechanisms controls myogenesis at all stages of development. Many aspects of adult myogenesis resemble or reiterate embryonic morphogenetic episodes, and related signaling mechanisms control the genetic networks that determine cell fate during these processes. An integrative view of all aspects of myogenesis is imperative for a comprehensive understanding of muscle formation. This article provides a holistic overview of the different stages and modes of myogenesis with an emphasis on the underlying signals, molecular switches, and genetic networks. © 2012 Cold Spring Harbor Laboratory Press; all rights reserved.
Welch V.A.,University of Ottawa
Systematic reviews | Year: 2013
At the Rio Summit in 2011 on Social Determinants of Health, the global community recognized a pressing need to take action on reducing health inequities. This requires an improved evidence base on the effects of national and international policies on health inequities. Although systematic reviews are recognized as an important source for evidence-informed policy, they have been criticized for failing to assess effects on health equity. This article summarizes guidance on both conducting systematic reviews with a focus on health equity and on methods to translate their findings to different audiences. This guidance was developed based on a series of methodology meetings, previous guidance, a recently developed reporting guideline for equity-focused systematic reviews (PRISMA-Equity 2012) and a systematic review of methods to assess health equity in systematic reviews. We make ten recommendations for conducting equity-focused systematic reviews; and five considerations for knowledge translation. Illustrative examples of equity-focused reviews are provided where these methods have been used. Implementation of the recommendations in this article is one step toward monitoring the impact of national and international policies and programs on health equity, as recommended by the 2011 World Conference on Social Determinants of Health.
Fitzpatrick E.M.,University of Ottawa
Systematic reviews | Year: 2013
Permanent childhood hearing loss affects 1 to 3 per 1000 children and frequently disrupts typical spoken language acquisition. Early identification of hearing loss through universal newborn hearing screening and the use of new hearing technologies including cochlear implants make spoken language an option for most children. However, there is no consensus on what constitutes optimal interventions for children when spoken language is the desired outcome. Intervention and educational approaches ranging from oral language only to oral language combined with various forms of sign language have evolved. Parents are therefore faced with important decisions in the first months of their child's life. This article presents the protocol for a systematic review of the effects of using sign language in combination with oral language intervention on spoken language acquisition. Studies addressing early intervention will be selected in which therapy involving oral language intervention and any form of sign language or sign support is used. Comparison groups will include children in early oral language intervention programs without sign support. The primary outcomes of interest to be examined include all measures of auditory, vocabulary, language, speech production, and speech intelligibility skills. We will include randomized controlled trials, controlled clinical trials, and other quasi-experimental designs that include comparator groups as well as prospective and retrospective cohort studies. Case-control, cross-sectional, case series, and case studies will be excluded. Several electronic databases will be searched (for example, MEDLINE, EMBASE, CINAHL, PsycINFO) as well as grey literature and key websites. We anticipate that a narrative synthesis of the evidence will be required. We will carry out meta-analysis for outcomes if clinical similarity, quantity and quality permit quantitative pooling of data. We will conduct subgroup analyses if possible according to severity/type of hearing disorder, age of identification, and type of hearing technology. This review will provide evidence on the effectiveness of using sign language in combination with oral language therapies for developing spoken language in children with hearing loss who are identified at a young age. The information from this review can provide guidance to parents and intervention specialists, inform policy decisions and provide directions for future research. CRD42013005426.
Deschamps F.,Montpellier University |
Godard M.,Montpellier University |
Guillot S.,French National Center for Scientific Research |
Hattori K.,University of Ottawa
Lithos | Year: 2013
Over the last decades, numerous studies have emphasized the role of serpentinites in the subduction zone geodynamics. Their presence and role in subduction environments are recognized through geophysical, geochemical and field observations of modern and ancient subduction zones and large amounts of geochemical database of serpentinites have been created. Here, we present a review of the geochemistry of serpentinites, based on the compilation of ~. 900 geochemical data of abyssal, mantle wedge and exhumed serpentinites after subduction. The aim was to better understand the geochemical evolution of these rocks during their subduction as well as their impact in the global geochemical cycle.When studying serpentinites, it is essential to determine their protoliths and their geological history before serpentinization. The geochemical data of serpentinites shows little mobility of compatible and rare earth elements (REE) at the scale of hand-specimen during their serpentinization. Thus, REE abundance can be used to identify the protolith for serpentinites, as well as magmatic processes such as melt/rock interactions before serpentinization. In the case of subducted serpentinites, the interpretation of trace element data is difficult due to the enrichments of light REE, independent of the nature of the protolith. We propose that enrichments are probably not related to serpentinization itself, but mostly due to (. sedimentary-derived) fluid/rock interactions within the subduction channel after the serpentinization. It is also possible that the enrichment reflects the geochemical signature of the mantle protolith itself which could derive from the less refractory continental lithosphere exhumed at the ocean-continent transition.Additionally, during the last ten years, numerous analyses have been carried out, notably using in situ approaches, to better constrain the behavior of fluid-mobile elements (FME; e.g. B, Li, Cl, As, Sb, U, Th, Sr) incorporated in serpentine phases. The abundance of these elements provides information related to the fluid/rock interactions during serpentinization and the behavior of FME, from their incorporation to their gradual release during subduction. Serpentinites are considered as a reservoir of the FME in subduction zones and their role, notably on arc magma composition, is underestimated presently in the global geochemical cycle. © 2013 Elsevier B.V.
Fullerton M.D.,University of Ottawa
Current Opinion in Lipidology | Year: 2016
Purpose of review The current review summarizes recent advancements in our mechanistic and physiological understanding of the energy sensing AMP-activated protein kinase (AMPK) and its regulation of select aspects of hepatic metabolism. Recent findings A highly conserved serine/threonine kinase, AMPK governs a multitude of cellular process to activate catabolic and inhibit anabolic pathways. Recent work has provided clarity as to the importance and contribution of the AMPK signaling cascade to various aspects of cellular metabolism, including lipid homeostasis, hepatic glucose production, mitochondrial metabolism, and autophagy. Summary With more than 60 confirmed substrates, the physiological significance of AMPK signaling has been difficult to ascertain. The generation of targeted knock-in mutations on key AMPK substrates has begun to shed light on this complex system. Future studies are needed to further decipher the complexity, significance, and potential therapeutic targeting of hepatic AMPK signaling. © 2016 Wolters Kluwer Health, Inc.
Toledo T.,Technion - Israel Institute of Technology |
Kolechkina T.,University of Ottawa
IEEE Transactions on Intelligent Transportation Systems | Year: 2013
This paper presents a general solution scheme for the problem of offline estimation of dynamic origin-destination (OD) demand matrices using traffic counts on some of the network links and historical demand information. The proposed method uses linear approximations of the assignment matrix, which maps the OD demand to link traffic counts. Several iterative algorithms that are based on this scheme are developed. The various algorithms are implemented in a tool that uses the mesoscopic traffic simulation model Mezzo to conduct network loadings. A case study network in Stockholm, Sweden, is used to test the proposed algorithms and to compare their performance with current state-of-the-art methods. The results demonstrate the applicability of the proposed methodology to efficiently obtain dynamic OD demand estimates for large and complex networks and that, computationally, this methodology outperforms existing methods. © 2000-2011 IEEE.
Bowen S.J.,University of Alberta |
Graham I.D.,University of Ottawa
Archives of Physical Medicine and Rehabilitation | Year: 2013
It is now accepted within health care that clinicians and managers should base their practice and decision making on evidence. One would think that this would be quite a simple undertaking - if good research is available and well communicated, people will act on it. But most of our efforts to date, which have focused largely on research transfer, have had modest success. This has created a need to reexamine the evidence - and the assumptions - on which our current knowledge-to-action activities are based. This article will summarize what is known about what works in promoting evidence-informed action, tracing the evolution from a linear focus on research transfer to complex strategies for user engagement. Using concrete examples, it will illustrate the strengths and limitations of various approaches and implications for rehabilitation medicine. © 2013 by the American Congress of Rehabilitation Medicine.
Austermann J.,Harvard University |
Mitrovica J.X.,Harvard University |
Latychev K.,University of Toronto |
Milne G.A.,University of Ottawa
Nature Geoscience | Year: 2013
The record of sea-level change at Barbados derived from the dating of fossil corals has been used to argue that globally averaged, or eustatic, sea level during the Last Glacial Maximum was approximately 120 m below present. This estimate is roughly 10 m lower than inferences based on sea-level data from other far-field sites and, if correct, would suggest that the Barbados record is a largely uncontaminated measure of eustasy. However, these previous analyses were based on numerical corrections for glacial isostatic adjustment that adopted one-dimensional viscoelastic Earth models. Here we assess the impact of three-dimensional mantle viscoelastic structure on predictions of post-glacial sea-level change at Barbados. Our simulations indicate that the predictions are strongly perturbed by the presence of a high-viscosity slab associated with subduction of the South American Plate beneath the Caribbean Plate. The slab suppresses local deformation and reduces the sea-level rise predicted during the deglaciation phase. To accommodate this reduction while maintaining a fit to the Barbados sea-level record requires an excess ice volume at the Last Glacial Maximum equivalent to about 130 m of eustatic sea-level rise. Given a downward revision in estimates of the Antarctic ice sheet contribution to this excess ice volume, we conclude that a significant amount of Northern Hemisphere ice at the Last Glacial Maximum remains unaccounted for in sea-level-based ice sheetreconstructions. © 2013 Macmillan Publishers Limited. All rights reserved.
Beaudoin T.,University of Ottawa
Canadian journal of microbiology | Year: 2010
Pseudomonas aeruginosa is an opportunistic pathogen that can form biofilms in the lungs and airways of cystic fibrosis (CF) patients, resulting in chronic endobronchial infection. Two clonal strains of P. aeruginosa, named type A and type B, have recently been identified and have been found to infect more than 20% of CF patients in Ontario, Canada. In this study, 4 type A and 4 type B isolates retrieved from 8 CF patients in Ontario, Canada, were characterized. All 8 isolates grew well in rich medium and formed biofilms in vitro. Antibiotic resistance profiles of bacteria grown in biofilms and planktonic culture were studied via minimal bactericidal concentration assays for tobramycin, gentamicin, and ciprofloxacin. Compared to laboratory strains of P. aeruginosa, all 8 isolates showed increased resistance to all antibiotics studied in both biofilm and planktonic assays. Gene expression analysis of mexX, representing the MexXY-OprM efflux pump, and mexA, representing MexAB-OprM, revealed that these genes were up-regulated in the 8 clinical isolates. These results suggest clonal type A and type B isolates of P. aeruginosa isolated from CF patients in Ontario, Canada, show a multidrug resistance pattern that can be partially explained as being due to the increased expression of common antibiotic efflux systems.
Jahn K.,University of Ottawa
BMC bioinformatics | Year: 2012
Mancheron, Uricaru and Rivals (Nucleic Acids Res. 39:e101, 2011) recently introduced a new approach in the context of multiple genome comparison that allows to detect regions of strong overlaps in a set of pairwise local alignments between several reference genomes and one target genome. Such overlap regions are an important source of information in genome annotation. In this paper we introduce a series of algorithms that improve over the approach of Mancheron et al., both in terms of computational complexity and in practical runtime. We also extend the problem definition such that overlaps to different reference genomes can be rated differently and regions overlapping only a subset of the reference genomes are detected.
Kurzrock R.,University of California at San Diego |
Stewart D.J.,University of Ottawa
Oncologist | Year: 2013
Regulations and ethical principles require that investigators seek consent and that patients participate in experimental studies only under circumstances that minimize the possibility of undue pressure and/or enticements.Inrecent years, there has been a rapid rise in the monitoring requirements of early-phase trials accompanied by an increasing emphasis on assuring "investigator" compliance with the protocol It is actually, however, the patient who must comply with the requirements of the study. If there is divergence from the protocol, investigators may be reported to regulatory bodies or agencies. Whereas the investigative community is expected to be vigilant about ensuring that patients participate in studies voluntarily and that their consent is procured without duress, it is also required to guarantee that complex protocols, which entail multiple procedures, be followed exactly by participants who suffer from the complications of advanced cancer.We explorethe issue of compliance in a research environment in which investigators are subject to disciplinary action if they fail to ensure that patients adhere precisely to the intense monitoring mandates of a clinical trial. © AlphaMed Press 2013.
Hamel M.-J.,University of Ottawa
Computer Assisted Language Learning | Year: 2012
This article reports on a study which took place in the context of the design and development of an online dictionary prototype for learners of French. Aspects of the 'usability', i.e. the quality of the 'learner-task-dictionary interaction' of the prototype were tested. Micro-tasks were designed to focus on learners' productive knowledge of French collocations. Learners (n = 6) completed the tasks individually, with access to the dictionary prototype. The computer sessions were screen-captured. The product (the language input provided by the learners) and the process (the learners' behavior) of the interaction were analyzed based on a set of defined effectiveness and efficiency parameters. The results provide an insight into the learners' dictionary search and look-up strategies highlight areas of the prototype's interface that deserve further design attention and consolidate the methodology used to test the usability of the prototype. © 2012 Copyright Taylor and Francis Group, LLC.
Menon K.,University of Ottawa
Pediatric critical care medicine : a journal of the Society of Critical Care Medicine and the World Federation of Pediatric Intensive and Critical Care Societies | Year: 2013
Limited evidence exists on the use of corticosteroids in pediatric shock. We sought to determine physicians' practices and beliefs with regard to the management of pediatric shock. Cross-sectional, Internet-based survey. Canada. Physicians identified as practicing pediatric intensive care in any of 15 academic centers. Seventy of 97 physicians (72.2%) responded. Physicians stated that they were more likely to prescribe steroids for septic shock than for shock following cardiac surgery (odds ratio, 1.9 [95% CI, 0.9-4.3]) or trauma (odds ratio, 11.46 [95% CI, 2.5-51.2]), and 91.4% (64/70) would administer steroids to patients who had received 60 cc/kg of fluid and two or more vasoactive medications. Thirty-five percent of respondents (25/70) reported that they rarely or never conducted adrenal axis testing before giving steroids to patients in shock. Eighty-seven percent of respondents (61/70) stated that the role of steroids in the treatment of fluid and/or vasoactive drug-dependent shock needed to be clarified and that 84.3% would be willing to randomize patients into a trial of steroid efficacy who were fluid resuscitated and on one high-dose vasoactive medication. However, 74.3% stated that they would start open-label steroids in patients who required two high-dose vasoactive medications. This survey provides information on the stated beliefs and practices of pediatric critical care physicians with regard to the use of steroids in fluid and/or vasoactive drug-dependent shock. Clinicians feel that the role of steroids in shock still requires clarification and that they would be willing to randomize patients into a trial. This survey may be useful as an initial framework for the development of a future trial on the use of steroids in pediatric shock.
Gadde S.,University of Ottawa
MedChemComm | Year: 2015
Recent progress in cellular biology has led to a paradigm shift in cancer therapies, from "one-drug-one-target" to "combination of drugs-multi-target" approaches to overcome several therapeutic challenges clinicians are facing today. While numerous drug combinations have successfully been identified through in vitro screening, their clinical success is still far from reality, due to dissimilarities in pharmacokinetics and tissue distribution of each drug in the combination, as well as more serious side effects because of differences in toxicity profiles. In recent years, nanoparticles have emerged as a promising class of carriers in co-delivery of multiple drugs for combination therapy. This review will focus on some of the advances and emerging features in multi-drug delivery platforms crucial to their success in in vivo models. In addition, this review will also discuss RNAi-based co-delivery platforms and their success in drug-resistant in vivo models. Packaging multiple drugs/agents in a single carrier (the "two-in-one" approach) and delivering them to tumor has the advantages of beneficially overlapping pharmacological profiles of drugs, reduced toxicity, and ratiometric drug delivery. This review will highlight the two-in-one approaches used in different co-delivery platforms and their chances of successful clinical translation. The emerging strategies discussed in this review are promising and may yield vast improvements in pharmacological control and offer the ability to personalize treatments to achieve maximum therapeutic synergy for each individual patient. © The Royal Society of Chemistry.
Ranasinghe P.,University of Ottawa
Theoretical Criminology | Year: 2013
While 'security' has now become a central theme in criminology, the literature on it is limited (and, limiting). One of the major issues plaguing the literature is definitional, that is, that it is often unclear what is meant by 'security'. As noted by numerous scholars, what is needed is empirical documentation about what 'security' is to a variety of actors. In this article, I explore what 'security' looks and feels like to particular actors working in an emergency shelter. In so doing, I explicate the discursive production of the polysemy of 'security' by exploring the ways that 'security' is thought about, made sense of and put into practice. © The Author(s) 2012.
Cordeiro C.M.,University of Ottawa
Recent patents on food, nutrition & agriculture | Year: 2011
The chicken eggshell and its membranes are an inexpensive and abundant waste material which exhibit interesting characteristics for many potential applications. The eggshell is formed mainly of calcium carbonate (CaCO3) and is used widely as an animal feed, lime (Ca(OH)2) substitute or a fertilizer. Moreover, the associated eggshell membranes have a high content of bioactive components, as well as properties of moisture retention and biodegradability which have potential use for clinical, cosmetic, nutraceutical and nanotechnology applications. The eggshell membranes have been also used for biosorption of heavy metals and dyes and as a template to synthesize metal nanoparticles. The combination of nanosized calcium phosphate (Ca3(PO4)2) biomaterials synthesized from eggshell and eggshell membrane show promise to develop drug delivery system and nanowires for electronic devices. In addition, a derived product, the soluble eggshell membrane protein (SEP) has applications in tissue engineering. This review discusses the patented applications of eggshell membrane waste: shell and membrane for the last 10 years as well as their future applications.
Mourad E.,Abu Dhabi University |
Nayak A.,University of Ottawa
IEEE Transactions on Parallel and Distributed Systems | Year: 2012
We consider the fault identification problem, also known as the system-level self-diagnosis, in multiprocessor and multicomputer systems using the comparison approach. In this diagnosis model, a set of tasks is assigned to pairs of nodes and their outcomes are compared by neighboring nodes. Given that comparisons are performed by the nodes themselves, faulty nodes can incorrectly claim that fault-free nodes are faulty or that faulty ones are fault-free. The collections of all agreements and disagreements, i.e., the comparison outcomes, among the nodes are used to identify the set of permanently faulty nodes. Since the introduction of the comparison model, significant progress has been made in both theory and practice associated with the original model and its offshoots. Nevertheless, the problem of efficiently identifying the set of faulty nodes when not all the comparison outcomes are available to the diagnosis algorithm at the beginning of the diagnosis phase, i.e., partial syndromes, remains an outstanding research issue. In this paper, we introduce a novel diagnosis approach using neural networks to solve this fault identification problem using partial syndromes. Results from a thorough simulation study demonstrate the effectiveness of the neural-network-based self-diagnosis algorithm for randomly generated diagnosable systems of different sizes and under various fault scenarios. We have then conducted extensive simulations using partial syndromes and nondiagnosable systems. Simulations showed that the neural-network-based diagnosis approach provided good results making it a viable addition or alternative to existing diagnosis algorithms. © 1990-2012 IEEE.
Evans B.W.,University of Washington |
Hattori K.,University of Ottawa |
Baronnet A.,Aix - Marseille University
Elements | Year: 2013
Rock-forming serpentine minerals form flat, cylindrical, and corrugated crystal microstructures, which reflect energetically efficient layering of alternate tetrahedral and octahedral sheets. Serpentinization of peridotite involves internal buffering of the pore fluid, reduction of oxygen fugacity, and partial oxidation of Fe2+ to Fe3+. Sluggish MgFe diffusion in olivine causes precipitation of magnetite and release of H 2. The tectonic environment of the serpentinization process dictates the abundance of fluid-mobile elements in serpentinites. Similar enrichment patterns of fluid-mobile elements in mantle-wedge serpentinites and arc magmas suggest a linkage between the dehydration of serpentinite and arc magmatism.
Stewart D.J.,University of Ottawa |
Kurzrock R.,University of California at San Diego
BMC Cancer | Year: 2013
Background: Randomized controlled trials with a survival endpoint are the gold standard for clinical research, but have failed to achieve cures for most advanced malignancies. The high costs of randomized clinical trials slow progress (thereby causing avoidable loss of life) and increase health care costs.Discussion: A malignancy may be caused by several different mutations. Therapies effective vs one mutation may be discarded due to lack of statistical significance across the entire population. Conversely, expensive large randomized trials may have sufficient statistical power to demonstrate benefit despite the therapy only working in subgroups. Non-cost-effective therapy is then applied to all patients (including subgroups it cannot help). Randomized trials comparing therapies with different mechanisms of action are misleading since they may conclude the therapies are " equivalent" despite benefitting different subpopulations, or may erroneously conclude that one therapy is superior simply because it targets a larger subpopulation. Furthermore, minor variances in patient selection may determine study outcome, a therapy may be discarded as ineffective despite substantial benefit in one subpopulation if harmful in another, randomized trials may more effectively detect therapies with minor benefit in most patients vs marked benefit in subpopulations, and randomized trials in unselected patients may erroneously conclude that " shot-gun" combinations are superior to single agents when sequential administration of personalized single agents might work better and spare patients treatment with drugs that cannot help them. We must identify predictive biomarkers early by comparing responding to progressing patients in phase I-II trials. Enriching randomized trials for biomarker-positive patients can markedly reduce required patient numbers and costs despite expensive screening for biomarker-positive patients. Available data support approval of new drugs without randomized trials if they yield single-agent sustained responses in patients refractory to standard therapies. Conversely, new approaches are needed to guide development of drug combinations since both standard phase II approaches and phase II-III randomized trials have a high risk of misleading.Summary: Traditional randomized clinical trials approaches are often inefficient, wasteful, and unreliable. New clinical research paradigms are needed. The primary outcome of clinical research should be " Who (if anyone) benefits?" rather than " Does the overall group benefit?" . © 2013 Stewart and Kurzrock; licensee BioMed Central Ltd.
Fung M.E.,University of Alberta |
Thebaud B.,Ottawa Hospital Research Institute |
Thebaud B.,University of Ottawa
Pediatric Research | Year: 2014
Bronchopulmonary dysplasia, the chronic lung disease of prematurity, is the most common complication in extremely premature infants (born before 28 wk gestation). Despite advances in perinatal care, modern clinical management remains devoid of therapies specifically promoting lung repair and lung growth. Recent progress in stem cell biology has uncovered the promise of stem/progenitor cells to repair damaged organs. Contrary to the original theory that stem cells engraft and repopulate the damaged organ, evidence suggests that stem cells act via a paracrine mechanism. This review highlights the preclinical evidence for the therapeutic potential of cell-based therapies in animal models of neonatal chronic lung injury and the multiple therapeutic avenues offered by soluble stem cell-derived factors. Copyright © 2014 International Pediatric Research Foundation, Inc.
Feng Z.,University of Science and Technology Beijing |
Liang M.,University of Ottawa |
Chu F.,Tsinghua University
Mechanical Systems and Signal Processing | Year: 2013
Nonstationary signal analysis is one of the main topics in the field of machinery fault diagnosis. Time-frequency analysis can identify the signal frequency components, reveals their time variant features, and is an effective tool to extract machinery health information contained in nonstationary signals. Various time-frequency analysis methods have been proposed and applied to machinery fault diagnosis. These include linear and bilinear time-frequency representations (e.g., wavelet transform, Cohen and affine class distributions), adaptive parametric time-frequency analysis (based on atomic decomposition and time-frequency auto-regressive moving average models), adaptive non-parametric time-frequency analysis (e.g., Hilbert-Huang transform, local mean decomposition, and energy separation), and time varying higher order spectra. This paper presents a systematic review of over 20 major such methods reported in more than 100 representative articles published since 1990. Their fundamental principles, advantages and disadvantages, and applications to fault diagnosis of machinery have been examined. Some examples have also been provided to illustrate their performance. © 2013 Elsevier Ltd.
Corrigan J.A.,University of Ottawa
Computers and Education | Year: 2012
While technology use is becoming ever more ubiquitous in society, there are times when even the most useful of technologies faces non-adoption for a variety of contextual reasons. Educational institutions are increasingly relying on online academic support services such as e-tutoring to balance rising demands for public accountability over standardized testing with decreasing budgets. This study explores the context of an e-tutoring service that has experienced a relatively low adoption rate in a school district in Eastern Ontario, Canada. The study proposes a model, based on the results of a mixed-methods diffusion study, for the effective implementation of the service; results indicate that this model is significantly correlated with the adoption of e-tutoring. Implications for the integration of educational technologies in secondary education, especially in relation to e-tutoring, are discussed. © 2012 Elsevier Ltd. All rights reserved.
Black J.L.,University of British Columbia |
Billette J.-M.,University of Ottawa
Applied Physiology, Nutrition and Metabolism | Year: 2013
National dietary guidelines pertaining to the intake of fruits and vegetables (FV) were recently amended, in both Canada and the United States, to provide specific recommendations about dark green and orange vegetables and juice consumption. However, little is known about the extent to which Canadians meet the updated recommendations for FV. This study fills current gaps by applying the National Cancer Institute's methodology for assessing the distribution of usual intake of foods to examine reported FV intake using 24-h recalls from the 2004 Canadian Community Health Survey, cycle 2.2, a nationally representative health survey. After identifying plausible respondents, usual intake distributions were estimated after adjustment for respondents' age, sex, body mass index, frequency of FV consumption, sequence effect, weekend-weekday effect, income, and ethnicity. The majority of Canadians did not meet Health Canada's 2007 recommendations for FV intake. Only 26% of the population aged 2 years and older consumed the minimum number of daily servings recommended for their respective age-sex group. Approximately 1 in 5 Canadians consumed at least 1 daily serving of dark green vegetables, and 9% consumed 1 or more daily servings of orange vegetables or their substitutes. Juice was a substantial contributor to FV intake, particularly for children and teens who, on average, consumed 32%-41% of their daily FV servings as juice. These findings provide insight into the quantity and composition of FV intake and adherence to national dietary recommendations in Canada.
Dales R.E.,University of Ottawa |
Cakmak S.,Health Canada |
Vidal C.B.,Area Descontaminacion Atmosferica
Journal of Thrombosis and Haemostasis | Year: 2010
Background: Ambient air pollution is a risk factor for stroke and myocardial infarction, possibly because of alterations in coagulation that influence the arterial circulation. Whether air pollution influences diseases associated with peripheral venous thrombogenesis remains largely unknown. Objectives: To determine the association between air pollution and venous thromboembolic disease (VTE) in a sample of the general population. Methods: A time-series analysis was used to test the association between daily air pollution and VTE hospitalizations in Santiago between 2001 and 2005. Results were adjusted for long-term trends, day of the week and average daily humidex. Results: From a population of 5.4 million, there were, on average, 2.3 admissions for VTE per day. Pooled estimates of relative risk (RR) [95% confidence interval (CI)] of hospitalization for venous disease were: 1.07 (1.05, 1.09) for a 58.4 p.p.b. increase in ozone (O3); 1.06 (1.02, 1.09) for a 5.85 p.p.b. increase in sulphur dioxide (SO2); 1.08 (1.03, 1.12) for a 29.25 μg/m3 increase in nitrogen dioxide (NO2); and 1.05 (1.03, 1.06) for a 20.02 μg/m3 increase in particulate matter ≤ 2.5 μm in mean aerodynamic diameter (PM2.5). For pulmonary embolism (PE) results were: 1.10 (1.07, 1.13) for O3; 1.05 (1.02, 1.08) for SO2; 1.07 (1.04, 1.09) for NO2; and 1.05(1.03, 1.06) for PM2.5, respectively. Conclusion: Air pollution appears to be a risk factor for venous thrombosis and PE, a disease with a significant fatality rate. © 2010 International Society on Thrombosis and Haemostasis.
Mattison D.R.,University of Ottawa
Journal of Population Therapeutics and Clinical Pharmacology | Year: 2013
Practitioners are often troubled by the lack of well characterized data on appropriate drug dosing, on effectiveness of treatment, and on drug safety for women and for women in pregnancy. We continue to struggle with how to best treat women during pregnancy and with the real life sex and gender differences in drug pharmacokinetics. This presentation looks at sex differences as a platform for considering the pharmacological status of women and how pregnancy changes that status. Specific examples of sex and gender differences in drug disposition/pharmacokinetics are discussed. The examples describe how sex-based differences influence treatment options and goals. © 2013 Canadian Society of Pharmacology and Therapeutics. All rights reserved.
Seely A.J.,University of Ottawa
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference | Year: 2011
Complex systems science has led to valuable insights regarding the care and understanding of critical illness, but has not led to fundamental improvements to care to date. Realizing the fact that there is inherent uncertainty in patient trajectory, we have developed Continuous Individual Multiorgan Variability Analysis (CIMVA) as a tool theoretically and practically designed to track the systemic emergent properties of the host response to injury or infection. We present an overview of CIMVA software, and discuss four separate potential clinical applications that we are evaluating; including early detection of infection, better prediction of extubation failure, continuous monitoring of severity of illness in the ICU, and the evaluation of cardiopulmonary fitness. Future challenges are discussed in conclusion.
Feng Z.,University of Science and Technology Beijing |
Chen X.,University of Science and Technology Beijing |
Liang M.,University of Ottawa
Mechanical Systems and Signal Processing | Year: 2015
The synchrosqueezing transform can effectively improve the readability of time-frequency representation of mono-component and constant frequency signals. However, for multi-component and time-variant frequency signals, it still suffers from time-frequency blurs. In order to address this issue, the synchrosqueezing transform is improved using iterative generalized demodulation. Firstly, the complex nonstationary signal is decomposed into mono-components of constant frequency by iterative generalized demodulation. Then, the instantaneous frequency of each mono-component is accurately estimated via the syn-chrosqueezing transform, by exploiting its merit of enhanced time-frequency resolution. Finally, the time-frequency representation of the original signal is obtained by superposing the time-frequency representations of all the mono-components with restored instantaneous frequency. This proposed method generalizes the synchrosqueezing transform to multi-component and time-variant frequency signals, and it has fine time-frequency resolution and is free of cross-term interferences. The proposed method was validated using both numerically simulated and lab experimental vibration signals of planetary gearboxes under nonstationary conditions. The time-variant planetary gearbox characteristic frequencies were effectively identified, and the gear faults were correctly diagnosed. © 2014 Elsevier Ltd. All rights reserved.
Stephan B.,University of Hamburg |
Paterson M.,University of Ottawa
Environmental Politics | Year: 2012
This overview of the existing political analysis of carbon markets identifies three broad strands in the literature. The first is concerned with the processes by which particular carbon market schemes are established. The second focuses on the role of particular actors in the creation of carbon markets. The third strand assesses carbon markets on efficiency, legitimacy or justice grounds. This existing literature is contrasted with the framework developed by the contributions to this volume. Broadly drawing on constructivist and poststructuralist approaches, the carbon economy is deconstructed, its history scrutinised and the practices and technologies that have been used to bring these markets into being are highlighted. Thus it is demonstrated that politics is not limited to the policy process leading up to the decision to implement an emissions trading scheme or offset mechanism, but is also present in the forms of knowledge claims that underpin these markets, as well as the various daily practices that constitute them. © 2012 Copyright Taylor and Francis Group, LLC.
Flynn A.B.,University of Ottawa
Journal of Chemical Education | Year: 2011
A unique approach to teaching and learning problem-solving and critical-thinking skills in the context of retrosynthetic analysis is described. In this approach, introductory organic chemistry students, who typically see only simple organic structures, undertook partial retrosynthetic analyses of real and complex synthetic targets. Multiple reasonable answers were possible for the questions, which provided a basis for the development of critical-thinking skills. A numbering system, described herein, was developed that enabled students to submit numeric clicker answers to a single or to multiple questions and thereby revealed the many ways that they had devised to disconnect these complex synthetic targets. The predominant student answers were readily gauged using the histogram function of the clicker program, which provided a basis for multiple relevant retrosynthetic analyses and enabled prompt, regular, and relevant feedback to be provided to students, even in moderate to very large classes. © 2011 The American Chemical Society and Division of Chemical Education, Inc.
Guillot S.,French National Center for Scientific Research |
Hattori K.,University of Ottawa
Elements | Year: 2013
Serpentinites are rocks consisting mostly of the serpentine-group minerals chrysotile, lizardite and antigorite. They are formed by the hydration of olivine-rich ultramafic rocks and they contain up to ∼13 wt% H2O. They have long been used by many cultures as building and carving stones. Serp entinites play essential roles in numerous geological settings. They act as a lubricant along plate boundaries during aseismic creep and contribute to the geochemical cycle of subduction zones. In the mantle, they are a reservoir of water and fluid-mobile elements. Serpentinites can produce nickel ore where weathered, and they can sequester CO2 where carbonated. They may have provided an environment for the abiotic generation of amino acids on the early Earth and other planets, potentially leading to the development of life.
Crosby E.,University of Ottawa
Canadian Journal of Anesthesia | Year: 2013
Purpose: The purpose of this narrative review is to discuss the impact of clinical practice guidelines on the outcomes of care and patient safety. Principal findings: The care provided to patients has a high degree of variability, including some care that is discordant with available evidence. This inconsistency has implications for patient safety as some patients receive care that is unlikely beneficial yet may be harmful, while others are denied care that would clearly be helpful. The medical literature is expanding at an alarming rate; its quality and reliability is often poor; study methodology is frequently suboptimal, and reversal is common, even among frequently cited articles. For decades, specialty societies and other agencies have been providing clinical practice guidelines to assist physicians with the integration of evidence into clinical decision-making. Implementation of guidelines has been variable, and their goals are often not achieved due to failed uptake and application. The reasons for this shortcoming are complex and some explanations are valid. Many guidelines have not been evidence-based and many have been methodologically unsound. Physician autonomy likely also plays an important role in guideline uptake; an updated concept of autonomy that embraces appropriate guidelines is long overdue. Conclusions: Under certain conditions, guidelines can add value to care and improve outcomes; they need to be evidence-based, methodologically sound, and appropriately applied to patients and clinical scenarios. Simply summarizing evidence in a guideline is an inadequate process. To achieve the benefit of guidelines, implementation strategies need to be robust. © 2012 Canadian Anesthesiologists' Society.
Kong S.,Northwestern University |
McBurney M.W.,University of Ottawa |
Fang D.,Northwestern University
Immunology and Cell Biology | Year: 2012
The NAD-dependent histone deacetylase sirtuin (Sirt)1 is implicated in a wide variety of physiological processes, ranging from tumorigenesis to mitochondrial biogenesis to neuronal development. Recent studies indicate that Sirt1 is a critical regulator of both the innate and adaptive immune response in mice and its altered functions are likely involved in autoimmune diseases. Small molecules that modulate Sirt1 functions are potential therapeutic reagents for autoimmune inflammatory diseases. In this review, we highlight the functions of Sirt1 in the immune system focusing on the underlying molecular mechanisms, and the potential of Sirt1 as a therapeutic target for autoimmune diseases. © 2012 Australasian Society for Immunology Inc. All rights reserved.
McLeman R.,University of Ottawa
Population and Environment | Year: 2010
This article describes and analyzes the impacts of population and demographic change on the vulnerability of communities to climate change and variability. It begins with a review of existing literature on the effects of population change on anthropogenic greenhouse gas emissions, the exposure of settlements to climate risks, and on the capacity to adapt to climate change. The article explores the relationship between population change and adaptive capacity through detailed examination of empirical findings from a study of small communities in eastern Ontario, Canada currently experiencing a combination of changes in local climatic conditions and rapid demographic change caused by in-migration of urban retirees and out-migration of young, educated people. The combination of changing demographic and climatic patterns has placed increased stress on local social networks that have long been critical to climate adaptation in that region. The case study and literature review are used to create a general typology of the relationship between population change and vulnerability that may be used as a framework for future research in this field. © 2009 Springer Science+Business Media, LLC.
Jacob M.D.,University of Ottawa
Nucleus (Austin, Tex.) | Year: 2012
The nucleolus is organized around a scaffolding of rDNA tandem repeats. These repeats, known as ribosomal cassettes, are each composed of ribosomal RNA (rRNA) genes preceding a long intergenic spacer (IGS) that has been classically perceived to be transcriptionally silent. Recent study of the IGS has contradicted the dogma that these spacers are merely inert regions of the genome, instead suggesting they are biologically significant, complex and plurifunctional transcriptional units that appear central to proper cellular functioning. Through the timely induction of various ribosomal IGS noncoding RNA (IGS RNA) transcripts, the cell is capable of both regulating rRNA synthesis and sequestering large numbers of proteins, thereby modulating essential molecular networks. Here we discuss our current understanding of the organization and function of the IGS.
Chen Y.,University of Ottawa |
Qian L.,Basic Medical Research Institute
Preventive Medicine | Year: 2012
Background: Obesity has been linked to stress, but there is lack of strong evidence from general populations. Methods: The analysis was based on data from 112,716 Canadians aged 18. years or more who participated in a national survey conducted in 2007-2008. A questionnaire covered the information on self-perceived lifetime stress, height, and weight. Logistic regression analysis was used to determine the association between chronic stress and obesity. Results: The crude prevalence of obesity was 18.1% for men and 16.0% for women. A small proportion (3.7%) of the participants reported being extremely stressed most days in their lives and 19.1% reported being quite a bit stressed, and the proportions of stress were slightly higher in women than in men. Overall, those who reported being extremely stressed (adjusted OR: 1.23, 95% CI: 1.13, 1.35) or those who reported being quite a bit stressed (adjusted OR: 1.08, 95% CI: 1.02, 1.15) had an increased risk of obesity compared with who were not at all stressed. The adjusted odds ratio was 1.44 (95% CI: 1.13, 1.35) for women who were extremely stressed compared with women who were not at all stressed. Conclusion: Lifetime stress was associated with an increased risk of obesity especially in women. © 2012 Elsevier Inc.
Zendejas B.,Rochester College |
Brydges R.,University of Toronto |
Brydges R.,A+ Network |
Hamstra S.J.,University of Ottawa |
And 2 more authors.
Annals of Surgery | Year: 2013
OBJECTIVE: Summarize the outcomes and best practices of simulation training for laparoscopic surgery. BACKGROUND: Simulation-based training for laparoscopic surgery has become a mainstay of surgical training. Much new evidence has accrued since previous reviews were published. METHODS: We systematically searched the literature through May 2011 for studies evaluating simulation, in comparison with no intervention or an alternate training activity, for training health professionals in laparoscopic surgery. Outcomes were classified as satisfaction, skills (in a test setting) of time (to perform the task), process (eg, performance rating), product (eg, knot strength), and behaviors when caring for patients. We used random effects to pool effect sizes. RESULTS: From 10,903 articles screened, we identified 219 eligible studies enrolling 7138 trainees, including 91 (42%) randomized trials. For comparisons with no intervention (n = 151 studies), pooled effect size (ES) favored simulation for outcomes of knowledge (1.18; N = 9 studies), skills time (1.13; N = 89), skills process (1.23; N = 114), skills product (1.09; N = 7), behavior time (1.15; N = 7), behavior process (1.22; N = 15), and patient effects (1.28; N = 1), all P < 0.05. When compared with nonsimulation instruction (n = 3 studies), results significantly favored simulation for outcomes of skills time (ES, 0.75) and skills process (ES, 0.54). Comparisons between different simulation interventions (n = 79 studies) clarified best practices. For example, in comparison with virtual reality, box trainers have similar effects for process skills outcomes and seem to be superior for outcomes of satisfaction and skills time. CONCLUSIONS: Simulation-based laparoscopic surgery training of health professionals has large benefits when compared with no intervention and is moderately more effective than nonsimulation instruction. Copyright © 2013 by Lippincott Williams & Wilkins.
Bourbonnais F.F.,University of Ottawa
Nephrology nursing journal : journal of the American Nephrology Nurses' Association | Year: 2012
This article describes the pain experience of patients on maintenance hemodialysis. Nephrology nurses have noted that patients on maintenance hemodialysis experience pain; however, it may not be adequately assessed or treated. A qualitative approach was utilized. Data were analyzed using content analysis. Twenty-five patients on outpatient hemodialysis were interviewed during their scheduled hemodialysis treatments. Patient pain experiences were related to physical pain, such as joint pain, as well as discomfort from being immobile. There were also descriptions of emotional and social pain. Patients utilized analgesics and other approaches, such as exercise, for pain. Patients also described pain management within the context of a dialysis unit. Patients'pain experiences require additional assessment and intervention. Further research is warranted to identify strategies to facilitate comfort.
Bickel D.R.,University of Ottawa
Biometrics | Year: 2011
In a novel approach to the multiple testing problem, Efron (2004,Journal of the American Statistical Association99, 96-104; 2007aJournal of the American Statistical Association102, 93-103; 2007b,Annals of Statistics35, 1351-1377) formulated estimators of the distribution of test statistics or nominalp-values under a null distribution suitable for modeling the data of thousands of unaffected genes, nonassociated single-nucleotide polymorphisms, or other biological features. Estimators of the null distribution can improve not only the empirical Bayes procedure for which it was originally intended, but also many other multiple-comparison procedures. Such estimators in some cases improve the proposed multiple-comparison procedure (MCP) based on a recent non-Bayesian framework of minimizing expected loss with respect to a confidence posterior, a probability distribution of confidence levels. The flexibility of that MCP is illustrated with a nonadditive loss function designed for genomic screening rather than for validation. The merit of estimating the null distribution is examined from the vantage point of the confidence-posterior MCP (CPMCP). In a generic simulation study of genome-scale multiple testing, conditioning the observed confidence level on the estimated null distribution as an approximate ancillary statistic markedly improved conditional inference. Specifically simulating gene expression data, however, indicates that estimation of the null distribution tends to exacerbate the conservative bias that results from modeling heavy-tailed data distributions with the normal family. To enable researchers to determine whether to rely on a particular estimated null distribution for inference or decision making, an information-theoretic score is provided. As the sum of the degree of ancillarity and the degree of inferential relevance, the score reflects the balance conditioning would strike between the two conflicting terms. The CPMCP and other methods introduced are applied to gene expression microarray data. © 2010, The International Biometric Society.
Liu W.,University of Ottawa
Nature Photonics | Year: 2016
Photonic signal processing has been considered a solution to overcome the inherent electronic speed limitations. Over the past few years, an impressive range of photonic integrated signal processors have been proposed, but they usually offer limited reconfigurability, a feature highly needed for the implementation of large-scale general-purpose photonic signal processors. Here, we report and experimentally demonstrate a fully reconfigurable photonic integrated signal processor based on an InP–InGaAsP material system. The proposed photonic signal processor is capable of performing reconfigurable signal processing functions including temporal integration, temporal differentiation and Hilbert transformation. The reconfigurability is achieved by controlling the injection currents to the active components of the signal processor. Our demonstration suggests great potential for chip-scale fully programmable all-optical signal processing. © 2016 Nature Publishing Group
Heintzman P.,University of Ottawa
Leisure Sciences | Year: 2010
This article examines empirical studies and theoretical models that explain the complex relationship between nature-based recreation and spirituality. Antecedent conditions include personal history, current circumstances, attitude, motivation, socio-demographic characteristics, and spiritual tradition. Setting components include being in nature, being away to a different environment, and place processes. Recreation components include activity, free time, solitude, group experiences, and facilitation. The article further explains how these conditions and components may lead to outcomes of spiritual experiences, spiritual well-being, and leisure-spiritual coping. Previous models have not taken into account the complexity of the nature-based recreation and spirituality relationship. Recommendations are made for future research and model development. © Taylor & Francis Group, LLC.
Schieda N.,University of Ottawa
Insights into Imaging | Year: 2013
Background:: Ferumoxytol is a safe and effective parenteral therapy used for the treatment of iron deficiency anaemia that has recently been approved for use in North America and in Europe. Methods:: Ferumoxytol consists of a superparamagnetic iron oxide (SPIO) core, which causes T1, T2 and T2* shortening effects, and a carbohydrate shell, which results in a prolonged intravascular half life. Results:: These properties are under-reported and not well recognised. They can interfere with MRI interpretation, potentially masking enhancement and rendering examinations non-diagnostic or simulating pathologic disease states. Both radiologists and non-radiologist physicians must consider the potential interaction of ferumoxytol with MRI when interpreting and prescribing MRI examinations in their patients. Main Messages: • Ferumoxytol has recently been approved for the treatment of iron deficiency anaemia. • Ferumoxytol is a small iron oxide particle with prolonged intravascular half life and T1, T2 and T2* shortening effects. • Administration of ferumoxytol can mask enhancement, rendering MRI studies potentially non-diagnostic. • Ferumoxytol can mimic diseases such as haemosiderosis, haemochromatosis and superficial siderosis. • Ferumoxytol interactions with MRI must be recognised by radiologists and non-radiologist physicians. © 2013 The Author(s).