Memorial University of Newfoundland, is a comprehensive university located primarily in St. John's, Newfoundland and Labrador, Canada. With historical strengths in education, engineering, business, geology, and medicine, it is one of the top comprehensive universities in Canada. With over 17,500 students, it is also the largest university in Atlantic Canada. MUN's four main campuses are served by more than 900 faculty and 2,300 staff members. Wikipedia.
News Article | April 20, 2017
Lyme disease is among the most common vector-borne illnesses in North America, Europe, and some parts of Asia. A spirochete bacterium called Borrelia burgdorferi causes the disease, and blacklegged ticks (Ixodes scapularis) are responsible for the majority of North American transmissions. Commonly known as deer ticks, blacklegged ticks exhibit two-year life cycles with the following four stages: eggs, larvae, nymphs, and adults. Larvae primarily attack white-footed mice, then become nymphs upon obtaining a blood meal. At the beginning of their second year, nymphs transform into adults and prey almost solely on white-tailed deer. Female ticks produce approximately 2,000 fertile eggs throughout their lives, nearly all of which hatch and continue the sequence. In the past, researchers have used various modeling techniques--including reaction-diffusion models, simulation models, and temperature-driven maps -- in attempts to better understand Lyme disease. In a paper publishing on Thursday, April 20 in the SIAM Journal on Applied Dynamical Systems, Xiunan Wang and Xiao-Qiang Zhao present a periodic time-delayed model of Lyme disease that incorporates seasonality and climate factors. "Seasonal variations in temperature, humidity, and resource availability have a strong effect on tick population dynamics," Wang said. "Climate impacts tick survival mostly during nonparasitic periods of the life cycle. Outside certain ranges of temperature and rainfall, tick populations cannot survive because these conditions directly kill the ticks or inhibit host-seeking activity." Previous models of the disease inspired the authors' current model, which handles seasonality and tick feeding activity particularly well. "We incorporate seasonality by assuming that the birth rate of ticks, the biting rate of ticks, and the strength of density dependence for adult ticks are positive, continuous, and periodic functions," Wang said. The authors address the larvae, nymph, and adult stages of the deer tick, and incorporate mice and deer as host populations. They identify three parameters to represent the different feeding durations of larvae, nymphs, and adults. "We need to be clear with the life cycle of ticks, including when they feed on two different hosts and how long they stay on the hosts," Wang said. "Involvement of three different tick life stages and two different hosts results in an eight-dimensional non-autonomous model with three different time delays." Wang and Zhao also identify variables for the densities of susceptible and infected mice, the densities of both uninfected and infected ticks at all stages of life, the density and birth rate of deer, mortality rates and feeding durations of all involved parties, susceptibility to infection, and individual biting rates of ticks. The authors evaluate all parameters and apply their model to Lyme disease transmission in Long Point, a hamlet in Ontario, Canada where the disease is widespread. "In recent years, northward invasive spread of the endemic tick vectors from the United States to nonendemic Canadian habitats has become a public health concern," Wang said. "Migratory songbirds play an integral role in the wide dispersal of ticks. Long Point Provincial Park on the northwestern shore of Lake Erie is famous for its migrating birds during spring and fall, and attracts thousands of birdwatchers. It is also one of the places where infected ticks are commonly found." Wang and Zhao utilize an existing algorithm to derive the basic reproduction ratio (R0), which acts as a threshold parameter when defining the model's global dynamics. They then use published data about monthly mean temperatures in Long Point from 1981-2010 to experiment with R0 levels, given changes in tick larvae birth rate. If R01, it will likely persist and exhibit periodic fluctuation. Ultimately, the authors' model yields a disease-free periodic solution. If nothing is done in the next few years, Lyme disease will be continue its prevalence in Long Point and exhibit periodic fluctuation. However, reducing the recruitment rate of tick larvae could eliminate it. The authors offer a few suggestions on how best to reduce this rate and prevent tick eggs from hatching into larvae. "It may be helpful to regularly search for the spots where adult ticks usually lay eggs, like in sheds, in woodpiles, under rocks, and in the crevices of walls," Wang said. "Since tick eggs are static, it is more feasible to focus on the clearance of eggs than to think about killing ticks of the other three life stages." However, because tick eggs are not macroscopically visible, Wang and Zhao suggest that the invention of equipment to detect them would certainly be useful. As long as the corresponding data is available, Wang and Zhao say that researchers can apply their model to the study of Lyme disease transmission in other parts of the world. They also hope to more thoroughly investigate ticks on songbirds, given the northward spread of the parasite to areas of Canada during migration season. "Since the ticks removed from songbirds consist of susceptible and infected nymphs, we may add a periodic function term into the susceptible and infectious nymph equations of our model, respectively," Wang said. "Such periodic terms can reflect the effect of seasonal migration of songbirds." Source article: Wang, X., & Zhao, X-Q. (2017). Dynamics of a Time-Delayed Lyme Disease Model with Seasonality. SIAM Journal on Applied Dynamical Systems. Xiunan Wang is a Ph.D. student in the Department of Mathematics and Statistics at the Memorial University of Newfoundland. Xiao-Qiang Zhao is a university research professor in the Department of Mathematics and Statistics at the Memorial University of Newfoundland. To obtain an advance copy of the paper or to schedule interviews with the authors, please email firstname.lastname@example.org. Reporters are free to use this text so long as they acknowledge SIAM.
Agency: European Commission | Branch: H2020 | Program: RIA | Phase: BG-02-2015 | Award Amount: 5.20M | Year: 2016
The overall goal of ClimeFish is to help ensure that the increase in seafood production comes in areas and for species where there is a potential for sustainable growth, given the expected developments in climate, thus contributing to robust employment and sustainable development of rural and coastal communities. The underlying biological models are based on single species distribution and production, as well as multispecies interactions. Forecasting models will provide production scenarios that will serve as input to socio-economic analysis where risks and opportunities are identified, and early warning methodologies are developed. Strategies to mitigate risk and utilize opportunities will be identified in co-creation with stakeholders, and will serve to strengthen the scientific advice, to improve long term production planning and the policy making process. ClimeFish will address 3 production sectors through 16 case studies involving 25 species, and study the predicted effects of 3 pre-defined climate scenarios. For 7 of these cases ClimeFish will develop specific management plans (MPs) coherent with the ecosystem approach and based on a results-based scheme that will allow regulators, fishers and aquaculture operators to anticipate, prepare and adapt to climate change while minimizing economic losses and social consequences. A guideline for how to make climate-enabled MPs will be produced, and published as a low-level, voluntary European standard after a consensus-based open consultation process. As a container for the models, scenarios and MPs ClimeFish will develop the ClimeFish Decision Support Framework (DSF) which also contains the ClimeFish Decision Support System (DSS); a software application with capabilities for what-if analysis and visualization of scenarios. The presence of key international stakeholders in the project will ensure quality and relevance of the project outputs thus ensuring uptake and significant impact also after project end.
Agency: European Commission | Branch: H2020 | Program: RIA | Phase: BG-10-2014 | Award Amount: 5.28M | Year: 2015
The overall aim of PrimeFish is to improve the economic sustainability of European fisheries and aquaculture sectors. PrimeFish will gather data from individual production companies, industry and sales organisations, consumers and public sources. The data will be related to the competitiveness and economic performance of companies in the sector; this includes data on price development, supply chain relations, markets, consumer behaviour and successful product innovation. The large industry reference group will facilitate access to data on specific case studies. A data repository will be created, and PrimeFish will join the H2020 Open Research Data Pilot to ensure future open access to the data. The effectiveness of demand stimulation through health, label and certification claims will be evaluated and compared with actual consumer behaviour. PrimeFish will assess the non-market value associated with aquaculture and captured fisheries as well as the effectiveness of regulatory systems and thereby provide the basis for improved societal decision making in the future. The collected data will be used to verify models and develop prediction algorithms that will be implemented into a computerized decision support system (PrimeDSS). The PrimeDSS, together with the underlying data, models, algorithms, assumptions and accompanying user instructions will form the PrimeFish Decision Support Framework (PrimeDSF). The lead users, typically fishermen, aquaculture producers and production companies, will be able to use the PrimeDSF to improve understanding of the functioning of their markets and in setting strategic plans for future production and innovation which in turn will strengthen the long term viability of the European fisheries and aquaculture sectors. This will also benefit consumers, leading to more diversified European seafood products, enhanced added value, novel products and improved information on origin, certification and health claims.
Agency: European Commission | Branch: H2020 | Program: RIA | Phase: SFS-09-2014 | Award Amount: 5.55M | Year: 2015
The European Union has committed to the gradual elimination of discarding. DiscardLess will help provide the knowledge, tools and technologies as well as the involvement of the stakeholders to achieve this. These will be integrated into Discard Mitigation Strategies (DMS) proposing cost-effective solutions at all stages of the seafood supply chain. The first focus is on preventing the unwanted catches from ever being caught. This will promote changes in gear using existing and innovative selectivity technology, and changes in fishing tactics based on fishers and scientists knowledge. The second focus is on making best use of the unavoidable unwanted catch. We will detail technical and marketing innovations from the deck, through the supply chain to the final market, including monitoring, traceability and valorization components. DiscardLess will evaluate the impacts of discarding on the marine environment, on the economy, and across the wider society. We will evaluate these impacts before, during and after the implementation of the landing obligation, allowing comparison between intentions and outcomes. Eliminating discards is as much a societal challenge as a fishery management one, so we will also evaluate stakeholders perception of discards. DiscardLess will describe the changes in management and the associated governance structures needed to cement the process. We will propose approaches to managing discards in a range of case study fisheries across Europe, encompassing differences in specific discarding issues. All these innovations will be combined in integrated Internet based interactive programs (DMS toolbox) that will help fishers to evaluate the present and future situation and to take a more qualified decision of how to adjust to the new regime. Also, we will disseminate the outcome of the project and maximize knowledge transfer across Europe through an educational environment teaching the next generation as well as more conventional routes.
Kovacs C.S.,Memorial University of Newfoundland
Physiological reviews | Year: 2014
Mineral and bone metabolism are regulated differently in utero compared with the adult. The fetal kidneys, intestines, and skeleton are not dominant sources of mineral supply for the fetus. Instead, the placenta meets the fetal need for mineral by actively transporting calcium, phosphorus, and magnesium from the maternal circulation. These minerals are maintained in the fetal circulation at higher concentrations than in the mother and normal adult, and such high levels appear necessary for the developing skeleton to accrete a normal amount of mineral by term. Parathyroid hormone (PTH) and calcitriol circulate at low concentrations in the fetal circulation. Fetal bone development and the regulation of serum minerals are critically dependent on PTH and PTH-related protein, but not vitamin D/calcitriol, fibroblast growth factor-23, calcitonin, or the sex steroids. After birth, the serum calcium falls and phosphorus rises before gradually reaching adult values over the subsequent 24-48 h. The intestines are the main source of mineral for the neonate, while the kidneys reabsorb mineral, and bone turnover contributes mineral to the circulation. This switch in the regulation of mineral homeostasis is triggered by loss of the placenta and a postnatal fall in serum calcium, and is followed in sequence by a rise in PTH and then an increase in calcitriol. Intestinal calcium absorption is initially a passive process facilitated by lactose, but later becomes active and calcitriol-dependent. However, calcitriol's role can be bypassed by increasing the calcium content of the diet, or by parenteral administration of calcium. Copyright © 2014 the American Physiological Society.
Mezey P.G.,Memorial University of Newfoundland
Accounts of Chemical Research | Year: 2014
ConspectusJust as complete molecules have no boundaries and have "fuzzy" electron density clouds approaching zero density exponentially at large distances from the nearest nucleus, a physically justified choice for electron density fragments exhibits similar behavior. Whereas fuzzy electron densities, just as any fuzzy object, such as a thicker cloud on a foggy day, do not lend themselves to easy visualization, one may partially overcome this by using isocontours. Whereas a faithful representation of the complete fuzzy density would need infinitely many such isocontours, nevertheless, by choosing a selected few, one can still obtain a limited pictorial representation. Clearly, such images are of limited value, and one better relies on more complete mathematical representations, using, for example, density matrices of fuzzy fragment densities. A fuzzy density fragmentation can be obtained in an exactly additive way, using the output from any of the common quantum chemical computational techniques, such as Hartree-Fock, MP2, and various density functional approaches.Such "fuzzy" electron density fragments properly represented have proven to be useful in a rather wide range of applications, for example, (a) using them as additive building blocks leading to efficient linear scaling macromolecular quantum chemistry computational techniques, (b) the study of quantum chemical functional groups, (c) using approximate fuzzy fragment information as allowed by the holographic electron density theorem, (d) the study of correlations between local shape and activity, including through-bond and through-space components of interactions between parts of molecules and relations between local molecular shape and substituent effects, (e) using them as tools of density matrix extrapolation in conformational changes, (f) physically valid averaging and statistical distribution of several local electron densities of common stoichiometry, useful in electron density databank mining, for example, in medicinal drug design, and (g) tools for combinatorial quantum chemistry approaches using fuzzy fragment databanks and rapid construction of a large number of approximate electron densities for large sets of related molecules, relevant in theoretical molecular and nanostructure design. © 2014 American Chemical Society.
Kovacs C.S.,Memorial University of Newfoundland
Annual Review of Nutrition | Year: 2012
Maternal adaptations during pregnancy and lactation appear to provide calcium to fetus and neonate without relying on vitamin D or calcitriol. Consequently, the blood calcium, calciotropic hormones, and skeleton appear normal at birth in the offspring of mothers who are severely vitamin D deficient or who lack calcitriol or its receptor. It remains unclear whether skeletal or extraskeletal problems will develop postnatally from exposure to vitamin D deficiency in utero. During the neonatal period, calcitriol-stimulated intestinal calcium absorption becomes the dominant mechanism of calcium delivery. The vitamin Ddeficient neonate is at risk to develop hypocalcemia, rickets, and possibly extraskeletal disorders (e.g., type 1 diabetes). Breastfed babies are at higher risk of vitamin D deficiency because normally little vitamin D or 25-hydroxyvitamin D passes into breast milk. Dosing recommendations during pregnancy and lactation should ensure that the baby is born vitamin D sufficient and maintained that way during infancy and beyond. Copyright ©2012 by Annual Reviews. All rights reserved.
Westley P.A.H.,Memorial University of Newfoundland
American Naturalist | Year: 2011
Biological invasions are opportunities to gain insight into fundamental evolutionary questions, because reproductive isolation and sudden alterations in selection pressures are likely to lead to rapid evolutionary change. Here I investigate the role played by invasive species in revealing the rate and form of contemporary phenotypic change in wild populations by expanding a database of more than 5,500 rates of phenotypic change from 90 species of plants and animals. Invasive species are frequently used as model organisms and thus contribute disproportionately to available rates of phenotypic change. However, the preponderance of these rates is the consequence of extensive study in a small number of species. I found mixed evidence to support the hypothesis that phenotypic change is associated with time depending on the metric of choice (i.e., darwins or haldanes). Insights from both invasive and native species provide evidence for abrupt phenotypic change and suggest that the environment plays a potentially important role in driving trait change in wild populations, although the environmental influence on the observed trajectories remains unclear. Thus, future work should continue to seek an understanding of the mechanistic underpinnings- both genetic and environmental-of how phenotypic variation allows populations to adapt to rapidly changing global environments. © 2011 by The University of Chicago.
Memorial University of Newfoundland | Date: 2016-08-17
An improved parallel kinematic mechanism to orient a platform has a higher range of motion for its volume due to the use of magnetically coupled ball joints at the orienting platform and the individual linear actuators operating those joints. The linear actuators may be printed circuit board (PCB) based voice coil actuators, in a magnetic field which may be generated by permanent magnets configured as a modified Halbach array. The PCB based voice coil actuators may have a position sensitive device (PSD) embedded on the PCB to assist in determining location of the actuator with a high degree of accuracy. The payload of the orienting platform may be dynamically repositioned with improved accuracy and speed.
Memorial University of Newfoundland | Date: 2016-10-06
An improved apparatus for processing sea cucumbers having stages for orienting/aligning, cutting, splitting, flattening, eviscerating and cleaning the sea cucumber, and for collecting the eviscerated innards. A method for the automated splitting and evisceration of sea cucumbers using the apparatus of the present disclosure. A flattening plate and trough during the orienting/aligning step relax the sea cucumber and discourage its defence mechanisms. A wedge shaped flattening plate splits and flattens the sea cucumber immediately after the incision. Pronged discs maintain positioning of the sea cucumber during an aggressive wash and brush cleaning cycle, which may be repeated. Optionally, a vacuum may suction off a portion of the innards prior to cleaning.