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Saskatoon, Canada

The University of Saskatchewan is a Canadian public research university, founded in 1907, and located on the east side of the South Saskatchewan River in Saskatoon, Saskatchewan, Canada. An "Act to establish and incorporate a University for the Province of Saskatchewan" was passed by the provincial legislature in 1907. It established the provincial university on April 3, 1907 "for the purpose of providing facilities for higher education in all its branches and enabling all persons without regard to race, creed or religion to take the fullest advantage". The University of Saskatchewan is now the largest education institution in the Canadian province of Saskatchewan.The university began as an agricultural college in 1907 and established the first Canadian university-based department of extension in 1910. 300 acres were set aside for university buildings and 1,000 acres for the U of S farm, and agricultural fields. In total 10.32 km2 was annexed for the university. The main University campus is situated upon 2,425 acres , with another 500 acres allocated for Innovation Place Research Park. The University of Saskatchewan agriculture college still has access to neighbouring urban research lands. The University of Saskatchewan's Vaccine and Infectious Disease Organization facility, develops DNA-enhanced immunization vaccines for both humans and animals.Since its origins as an agricultural college, research has played an important role at the university. Discoveries made at the U of S include sulphate-resistant cement and the cobalt-60 cancer therapy unit. The university offers over 200 academic programs. Duncan P. McColl was appointed as the first registrar, establishing the first convocation from which Chief Justice Edward L. Wetmore was elected as the first chancellor. Walter Charles Murray became the first president of the university's board of governors. Wikipedia.


Vishniac E.T.,University of Saskatchewan | Shapovalov D.,Johns Hopkins University
Astrophysical Journal | Year: 2014

We study the flux of small-scale magnetic helicity in simulations of driven statistically homogeneous magnetohydrodynamic turbulence in a periodic box with an imposed large-scale shear. The simulations show that in the regime of strong dynamo action the eddy-scale magnetic helicity flux has only two significant terms: advective motion driven by the large-scale velocity field and the Vishniac-Cho (VC) flux which moves helicity across the magnetic field lines. The contribution of all the other terms is negligible. The VC flux is highly correlated with the large-scale electromotive force and is responsible for large-scale dynamo action, while the advective term is not. The VC flux is driven by the anisotropy of the turbulence. We derive analytical expressions for it in terms of the small-scale velocity or magnetic field. These expressions are used to predict the existence and strength of dynamo action for different turbulent anisotropies and tested against the results of the simulations. © 2014. The American Astronomical Society. All rights reserved. Source


Butler S.L.,University of Saskatchewan
Physics of Fluids | Year: 2011

Mushy layers are known to occur in magma chambers, sea-ice, and metal castings. They are often modeled as a porous layer in which a fluid and solid matrix exist in thermal and compositional equilibria. In nonreactive porous media, both advective and diffusive transport rates for heat and solute differ. In mushy layers, however, the temperature and composition of the fluid phase are constrained by the liquidus relationship giving rise to effective transport rates that are intermediate between those for heat and solute in passive porous layers. The transport of heat and solute, even if the invading fluid is itself in equilibrium, is also accompanied by a degree of solidification or melting due to the difference in the transport rates for these two quantities. In this paper, analytical expressions for the effective velocity and diffusivity in a mushy layer and for the degree of melting or solidification accompanying the passage of a front with a different temperature and composition are derived and compared with the predictions of a numerical model and found to be in very good agreement. Characteristic parameters for a few mushy systems are calculated and appropriate transport and melting/freezing regimes are indicated. © 2011 American Institute of Physics. Source


Walker A.D.M.,University of KwaZulu - Natal | Sofko G.J.,University of Saskatchewan
Annales Geophysicae | Year: 2016

When studying magnetospheric convection, it is often necessary to map the steady-state electric field, measured at some point on a magnetic field line, to a magnetically conjugate point in the other hemisphere, or the equatorial plane, or at the position of a satellite. Such mapping is relatively easy in a dipole field although the appropriate formulae are not easily accessible. They are derived and reviewed here with some examples. It is not possible to derive such formulae in more realistic geomagnetic field models. A new method is described in this paper for accurate mapping of electric fields along field lines, which can be used for any field model in which the magnetic field and its spatial derivatives can be computed. From the spatial derivatives of the magnetic field three first order differential equations are derived for the components of the normalized element of separation of two closely spaced field lines. These can be integrated along with the magnetic field tracing equations and Faraday's law used to obtain the electric field as a function of distance measured along the magnetic field line. The method is tested in a simple model consisting of a dipole field plus a magnetotail model. The method is shown to be accurate, convenient, and suitable for use with more realistic geomagnetic field models. © 2016 Author(s). Source


Jones B.,University of Alberta | Renaut R.W.,University of Saskatchewan
Developments in Sedimentology | Year: 2010

Spring systems encompass a tremendous range of environmental niches where calcareous deposits commonly form. Although active springs have been classified according to their water temperature (cold to hot) or water source (thermogene and meteogene), such classifications are difficult to apply to (sub)fossil systems where water is no longer flowing. Although the deposits formed in these settings have long been referred to as tufa or travertine, the distinction between these terms has been largely debased through inconsistent usage. The precipitation of calcite as opposed to aragonite in spring systems has been variously attributed to water composition, water temperature, growth inhibitors (e.g., Mg/Ca ratio), and/or CO 2 degassing and saturation levels. In springs, the rate of CO 2 degassing, a fundamental control on the degree of CaCO 3 supersaturation, seems to exert considerable influence over carbonate precipitation as well as the morphology of crystals that form. Rapid CO 2 degassing, for example, seems to be responsible for the precipitation of large, dendritic calcite crystals that characterize many spring deposits throughout the world. Common facies in calcareous spring deposits include plant, insect, shrub, coated grain, stalactite, lithoclastic-bioclastic, micritic, raft, coated bubble, and crystalline tufa or travertine. Plants and microbes are commonly involved in the development of many of these facies and seasonal variations in calcite or aragonite precipitation are commonly apparent. Early diagenetic processes, including cementation, dissolution, and recrystallization, result from subsurface spring waters that readily flow through initially porous deposits, and from percolating runoff waters. As yet, no universal classification system copes with the full range of calcareous spring deposits. Most current classifications reflect the deposit(s) on which they were based and little attempt has been made to develop a system that reflects the variations related to climate and the scale of the deposit. Many aspects of calcareous spring deposits remain enigmatic. © 2010 Elsevier B.V. All rights reserved. Source


Nacke L.E.,University of Saskatchewan
Future Play 2010: Research, Play, Share - International Academic Conference on the Future of Game Design and Technology | Year: 2010

Psychophysiological methods provide covert and reliable affective measurements of user experience (UX). The nature of affective UX in interactive entertainment is currently not well understood. With the dawn of new gaming consoles, scientific methodologies for studying user interaction in immersive entertainment (e.g., digital gaming) are needed. This paper reports a study on the influence of interaction modes (Playstation 2 game controller vs. Wii remote and Nunchuk) on subjective experience and brain activity measured with electroencephalography (EEG). Results indicate that EEG alpha and delta power correlate with negative affect and tension when using regular game controller input. EEG beta and gamma power seem to be related to the feeling of possible actions in spatial presence with a PS2 game controller. Delta as well as theta power correlate with self-location using a Wii remote and Nunchuk. © 2010 ACM. Source


Anwar M.,University of Pittsburgh | Greer J.,University of Saskatchewan
IEEE Transactions on Learning Technologies | Year: 2012

This research explores a new model for facilitating trust in online e-learning activities. We begin by protecting the privacy of learners through identity management (IM), where personal information can be protected through some degree of participant anonymity or pseudonymity. In order to expect learners to trust other pseudonymous participants, we realize that a reliable mechanism is needed for managing participants' reputations and assuring that such reputations are legitimately obtained. Further, because participants can hold multiple identities or can adopt new pseudonymous personas, a reliable and trustworthy mechanism for reputation transfer (RT) from one persona to another is required. Such a reputation transfer model must preserve privacy and at the same time prevent linkability of learners' identities and personas. In this paper, we present a privacy-preserving reputation management (RM) system which allows secure transfer of reputation. A prototypical implementation of our reputation transfer protocol and the successful experimental deployment of our reputation management solution in an e-learning discussion forum serve as a proof of concept. © 2008-2011 IEEE. Source


Phan A.H.,University of New South Wales | Tuan H.D.,University of Technology, Sydney | Kha H.H.,University of Technology, Sydney | Nguyen H.H.,University of Saskatchewan
IEEE Transactions on Wireless Communications | Year: 2012

Optimization problems of beamforming in multi-user amplify-and-forward (AF) wireless relay networks are indefinite (nonconvex) quadratic programs, which require effective computational solutions. Solutions to these problems have often been obtained by relaxing the original problems to semi-definite programs (SDPs) of convex optimization. Most existing works have claimed that these relaxed SDPs actually provide the optimal beamforming solutions. This paper, however, shows that this is not the case in many practical scenarios where SDPs fail to provide even a feasible beamforming solution. To fill this gap, we develop in this paper a nonsmooth optimization algorithm, which provides the optimal solution at low computational complexity. © 2012 IEEE. Source


Sila I.,Kadir Has University | Dobni D.,University of Saskatchewan
Industrial Management and Data Systems | Year: 2012

Purpose - The purpose of this paper is to identify the B2B e-commerce (B2BEC) usage patterns of North American small- and medium-sized enterprises (SMEs) in their supply chains, the contextual factors that influence usage patterns, and the subsequent effects of these patterns on firm performance. Design/methodology/approach - The authors conducted an online survey of North American SMEs and obtained 229 responses. They utilized several statistical methods, including cluster analysis and profile analysis, to test five hypotheses. Findings - The TOE framework, supplemented with interorganizational factors, provides a valid theoretical guideline to study firms' B2BEC usage patterns. Three distinct types of B2BEC usage patterns - E-Limiteds, E-Leaders, and E-Laggards - emerged. Different sets of contextual factors contribute to the formation of these three patterns of B2BEC adoption. Higher levels of B2BEC usage result in stronger firm performance. Research limitations/implications - Future clustering variables could be more specific. The effects of other potential contextual factors should also be explored by future studies. This study can be replicated in other countries to determine whether the findings can be generalized. Practical implications - In light of the potential performance improvements that B2BEC adoption offers, managers should assess the risks associated with maintaining their current speed of e-business deployment versus the risks associated with escalating it. Organizations that have been more reactive should consider how well or ill their sluggish approach prepares them for navigating the inevitability of increasing sophistication in supply chain management. Originality/value - Limited empirical research exists on theB2BECusage patterns of NorthAmerican SMEs, the contextual factors that motivate them to adopt different B2BEC technologies in their supply chains, and how each of these usage patterns affects their performance. The current study contributes to the literature by shedding light on these issues. © Emerald Group Publishing Limited. Source


Zhang H.,University of Victoria | Shi Y.,University of Victoria | Saadat Mehr A.,University of Saskatchewan
IEEE Transactions on Fuzzy Systems | Year: 2012

In this paper, we present a new design method for the H ∞ filtering of discrete-time Takagi-Sugeno (TS) fuzzy systems. The parameters of the filter are assumed to be linearly dependent on the normalized fuzzy weighting functions. By using an augmentation technique, the design parameters are incorporated into a filtering error system. In order to derive less-conservative results and reduce the filtering error, a new condition is established to ensure the H ∞ performance of the filtering error system. By introducing more slack matrices, the solution set of the filter parameters is extended. By using a partitioning technique, a design method for the H ∞ filter is proposed in terms of linear matrix inequalities (LMIs). An example demonstrates the improvement of the proposed design method over an existing approach. © 2012 IEEE. Source


Zhang H.,University of Victoria | Shi Y.,University of Victoria | Saadat Mehr A.,University of Saskatchewan
IET Control Theory and Applications | Year: 2010

This study is concerned with the robust energy-to-peak (l 2-l∞) filtering problem for a class of uncertain linear discrete-time networked control systems with time-varying delays and randomly missing data. The system matrices are assumed to reside in a convex polytope, and the time-varying delays appearing in system states are assumed to lie in a given interval. Moreover, the random data missing is supposed to satisfy the Bernoulli random binary distribution. The authors' goal is to design a full-order filter such that the filtering error dynamic system is exponentially mean-square stable for all admissible time delays and randomly missing data while a prescribed l2-l∞ performance is achieved. Sufficient delay-and parameter-dependent conditions for the existence of the filter and for the solvability of the addressed problem are given in terms of a set of linear matrix inequalities. Finally, simulation examples and comparison studies are provided to demonstrate the effectiveness of the proposed approach. © 2010 The Institution of Engineering and Technology. Source


Zhang H.,University of Victoria | Mehr A.S.,University of Saskatchewan | Shi Y.,University of Victoria
Signal Processing | Year: 2010

This paper investigates the problem of energy-to-peak filtering for both discrete-time and continuous-time systems with polyhedral uncertainties in the state-space equations. By increasing the flexible dimensions in the solution space for the energy-to-peak optimization, less conservative results on the robust energy-to-peak filtering are obtained. The filter parameters can be readily designed by solving a set of parameter-dependent linear matrix inequalities (LMIs). In comparison with the existing methods, the improvement of the proposed method over the existing results is shown via two numerical examples. © 2010 Elsevier B.V. All rights reserved. Source


Ferguson G.,University of Saskatchewan | Grasby S.E.,Geological Survey of Canada
Hydrogeology Journal | Year: 2014

The Winnipeg and Deadwood formations form deep clastic reservoirs in Saskatchewan, Canada, with temperatures exceeding 40°C over most of southern Saskatchewan and reaching 100°C in southwestern Saskatchewan. At these temperatures, the formations have geothermal potential for development of direct use and electricity generation systems. Numerous disposal wells operating at rates of 30L/s or more are currently installed in these formations, suggesting that electricity could be generated at rates exceeding 2 megawatts of electrical output (MWe) from individual wells. These basal clastic units, thus, could provide significant energy supply over a broad region of Saskatchewan. © Her Majesty the Queen in Right of Canada 2013. Source


Roy C.K.,University of Saskatchewan | Cordy J.R.,Queens University
Journal of Software Maintenance and Evolution | Year: 2010

The new hybrid clone detection tool NICAD combines the strengths and overcomes the limitations of both text-based and AST-based clone detection techniques and exploits novel applications of a source transformation system to yield highly accurate identification of cloned code in software systems. In this paper, we present an in-depth study of near-miss function clones in open source software using NICAD. We examine more than 20 open source C, Java and C# systems, including the entire Linux Kernel, Apache httpd, J2SDK-Swing and db4o and compare their use of cloned code in several different dimensions, including language, clone size, clone similarity, clone location and clone density both by proportion of cloned functions and lines of cloned code. We manually verify all detected clones and provide a complete catalogue of different clones in an online repository in a variety of formats. These validated results can be used as a cloning reference for these systems and as a benchmark for evaluating other clone detection tools. Copyright © 2009 John Wiley & Sons, Ltd. Source


Jukanti A.K.,Indian International Crops Research Institute for the Semi Arid Tropics | Gaur P.M.,Indian International Crops Research Institute for the Semi Arid Tropics | Gowda C.L.L.,Indian International Crops Research Institute for the Semi Arid Tropics | Chibbar R.N.,University of Saskatchewan
British Journal of Nutrition | Year: 2012

Chickpea (Cicer arietinum L.) is an important pulse crop grown and consumed all over the world, especially in the Afro-Asian countries. It is a good source of carbohydrates and protein, and protein quality is considered to be better than other pulses. Chickpea has significant amounts of all the essential amino acids except sulphur-containing amino acids, which can be complemented by adding cereals to the daily diet. Starch is the major storage carbohydrate followed by dietary fibre, oligosaccharides and simple sugars such as glucose and sucrose. Although lipids are present in low amounts, chickpea is rich in nutritionally important unsaturated fatty acids such as linoleic and oleic acids. Î 2-Sitosterol, campesterol and stigmasterol are important sterols present in chickpea oil. Ca, Mg, P and, especially, K are also present in chickpea seeds. Chickpea is a good source of important vitamins such as riboflavin, niacin, thiamin, folate and the vitamin A precursor Î 2-carotene. As with other pulses, chickpea seeds also contain anti-nutritional factors which can be reduced or eliminated by different cooking techniques. Chickpea has several potential health benefits, and, in combination with other pulses and cereals, it could have beneficial effects on some of the important human diseases such as CVD, type 2 diabetes, digestive diseases and some cancers. Overall, chickpea is an important pulse crop with a diverse array of potential nutritional and health benefits. © 2012 The Authors. Source


Angerer T.,University of Western Australia | Kerrich R.,University of Saskatchewan | Hagemann S.G.,University of Western Australia
Precambrian Research | Year: 2013

Komatiite-basalt magmatism and Algoma-type banded iron formation (BIF) of Archean greenstone terranes have common time series, but there are few constraints on the geodynamic setting in which BIF were precipitated. The ∼3.0Ga Koolyanobbing greenstone belt (KGB), Southern Cross Domain, Yilgarn craton, exhibits an greenschist to lower amphibolite facies metamorphosed lithostratigraphic series, including four predominantly mafic to ultramafic volcanic sequences (S1-S4) with prominent BIF horizons (and local basal pyrite-dominated massive sulfide lenses) in between. Petrography, XRD, high-precision major, trace high field strength, and REE element chemistry of representative ultramafic and mafic rocks from S1, S2, and S3 are consistent with a komatiitic, boninitic, and tholeiitic basalt association. Komatiites are Al-depleted and Al-undepleted (Al2O3/TiO2 12-28 and (Gd/Yb)N, ≥1) endorsing a zoned plume and/or melting over a range of depths. The boninite-series rocks (Al2O3/TiO2 28-45 and (Gd/Yb)N, <1) preserve characteristic U-shaped REE patterns and positive Zr-Hf/MREE anomalies. Komatiites include uncontaminated members and counterparts contaminated by metasomatized continental mantle lithosphere, suggesting eruption proximal to a rifted arc setting, whereas boninite-series were erupted at an intraoceanic arc, collectively consistent with plume eruption into a convergent margin. Al-depleted and Al-undepleted komatiites plot close together to the mantle array on the Th/Yb versus Nb/Yb discrimination plot of Pearce (2008), implying a depleted, mildly heterogeneous, source for the mantle plume from which komatiites erupted. Boninites lie parallel to and above the mantle array, in the field of intraoceanic arcs, in keeping with their inferred oceanic convergent margin setting. Ratios of Nb/Yb extend to lower and higher values than komatiites implying a more heterogeneous upper mantle source of the subarc wedge.The KGB exhibits the first reported boninite-suite rocks in the Southern Cross Domain, Yilgarn craton. Conclusively, the komatiitic, boninitic, and tholeiitic basalt association suggests that BIF and basal massive pyrite lenses of the Koolyanobbing greenstone belt were precipitated from low-temperature submarine discharge of a seawater-dominated hydrothermal system driven by magmatic systems of a mantle plume erupting in a forearc convergent margin suprasubduction ophiolite. © 2012 Elsevier B.V. Source


Madill S.J.,University of Saskatchewan | Pontbriand-Drolet S.,University of Montreal | Tang A.,University of Montreal | Dumoulin C.,University of Montreal
Neurourology and Urodynamics | Year: 2013

Aims The purpose of this study was to examine the effect of a pelvic floor muscle (PFM) rehabilitation program on incontinence symptoms, PFM function, and morphology in older women with SUI. Methods Women 60 years old and older with at least weekly episodes of SUI were recruited. Participants were evaluated before and after a 12-week group PFM rehabilitation intervention. The evaluations included 3-day bladder diaries, symptom, and quality of life questionnaires, PFM function testing with dynamometry (force) and electromyography (activation) during seven tasks: rest, PFM maximum voluntary contraction (MVC), straining, rapid-repeated PFM contractions, a 60 sec sustained PFM contraction, a single cough and three repeated coughs, and sagittal MRI recorded at rest, during PFM MVCs and during straining to assess PFM morphology. Results Seventeen women (68.9 ± 5.5 years) participated. Following the intervention the frequency of urine leakage decreased and disease-specific quality of life improved significantly. PFM function improved significantly: the participants were able to perform more rapid-repeated PFM contractions; they activated their PFMs sooner when coughing and they were better able to maintain a PFM contraction between repeated coughs. Pelvic organ support improved significantly: the anorectal angle was decreased and the urethrovescial junction was higher at rest, during contraction and while straining. Conclusions This study indicated that improvements in urine leakage were produced along with improvements in PFM co-ordination (demonstrated by the increased number of rapid PFM contractions and the earlier PFM activation when coughing), motor-control, pelvic organ support. © 2013 Wiley Periodicals, Inc. Source


Steer R.P.,University of Saskatchewan
Photochemical and Photobiological Sciences | Year: 2014

The relaxation dynamics of electronically excited porphyrinoids are often measured by steady-state and time-resolved fluorescence methods. The unusual occurrence of measurable fluorescence from an upper excited singlet state (often identified as the second electronically excited singlet state, S2) of some porphyrins has, in recent years, prompted a spate of mis-assignments of observed emission from other porphyrinoids excited in the near UV-violet regions of the spectrum. The criteria for correctly assigning fluorescence to a Soret excited state are reviewed. Questionable and mis-assigned reports are identified. This journal is © the Partner Organisations 2014. Source


Bewer B.,University of Saskatchewan
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment | Year: 2011

Using a monochromatic X-ray beam from a synchrotron source the electron density of a homogeneous target was determined by measuring the refraction that occurs at the airtarget interface for a known angle of incidence. The angle of deviation that these X-rays undergo at the transition between materials is micro-radian to submicro-radian in scale. Existing analyzer based imaging systems are designed to measure submicro-radian angle changes and commonly use monochromatic hard X-ray beams generated from synchrotron sources. A preliminary experiment using the analyzer based imaging apparatus at the Canadian Light Source Biomedical Imaging and Therapy beamline and a half cylinder shaped plastic target will be presented. By measuring the angle of deviation of the photon beam at several discrete angular positions of the target the electron density of the target material was determined. © 2011 Elsevier B.V. All rights reserved. Source


Seshia S.S.,University of Saskatchewan
Current Pain and Headache Reports | Year: 2012

Chronic daily headache (CDH) may be primary or secondary. Secondary causes can be suspected through "red flags" in the history and examination. With a prevalence of at least 1% and several associations, primary CDH is a common, often complex, chronic pain syndrome in children and adolescents. The intricate associations between stressors, psychiatric disorders (especially anxiety and depression), and CDH can be explained by "the limbically augmented pain syndrome" proposed by Rome and Rome. Disorders of sleep and other pain syndromes also may co-occur. For these reasons, a multiaxial classification is ideal. Many with primary CDH have features of both chronic migraine and chronic tension-type headache, contributing to confusion in subtyping. Primary CDH is often transformed from a primary episodic headache type, stressors being most responsible. Genetic factors also may facilitate chronification. Management should be biopsychosocial, family-centered, and often multidisciplinary, drugs being only one component. Treatment is still based on consensus, not evidence. Girls, migraineurs, and those with psychiatric comorbidity, medication overuse, and CDH onset before the age of 13 years and lasting for 2 years or longer, are at high risk for persistence; hence, such patients should be followed up into adult life. A classification for CDH should be included in the third edition of the International Classification of Headache Disorders. © 2011 Springer Science+Business Media, LLC. Source


Latimer A.E.,Queens University | Brawley L.R.,University of Saskatchewan | Bassett R.L.,McMaster University
International Journal of Behavioral Nutrition and Physical Activity | Year: 2010

Background: To motivate individuals to adhere to a regular physical activity regime, guidelines must be supplemented with persuasive messages that are disseminated widely. While substantial research has examined effective strategies for disseminating physical activity messages, there has been no systematic effort to examine optimal message content. This paper reviews studies that evaluate the effectiveness of three approaches for constructing physical activity messages including tailoring messages to suit individual characteristics of message recipients (message tailoring), framing messages in terms of gains versus losses (message framing), and targeting messages to affect change in self-efficacy (i.e., a theoretical determinant of behavior change).Methods: We searched the MEDLINE, PsycINFO, EMBASE and CINAHL databases up to July 2008. Relevant reference lists also were searched. We included intervention trials, field experiments, and laboratory-based studies that aimed to test the efficacy or effectiveness of tailored messages, framed messages and self-efficacy change messages among healthy adults. We used a descriptive approach to analyze emerging patterns in research findings. Based on this evidence we made recommendations for practice and future research.Results: Twenty-two studies were identified. Twelve studies evaluated message tailoring. In 10 of these studies, tailored messages resulted in greater physical activity than a control message. Six studies evaluated framed messages. Five of these studies demonstrated that gain-framed messages lead to stronger intentions to be active compared to a control message. Moreover, a gain-frame advantage was evident in three of the four studies that assessed physical activity. Four studies evaluated self-efficacy change messages. The two studies that used an experimental design provide a clear indication that individuals' beliefs can be affected by messages that incorporate types of information known to be determinants of self-efficacy. Overall, strong evidence to support definitive recommendations for optimal message content and structure was lacking.Conclusions: Additional research testing the optimal content of messages used to supplement physical activity guidelines is needed. Tailored messages, gain-framed messages, and self-efficacy change messages hold promise as strategies for constructing physical activity messages and should be a focus of future research. © 2010 Latimer et al; licensee BioMed Central Ltd. Source


Pozniak C.J.,University of Saskatchewan
Canadian Journal of Plant Science | Year: 2013

CDC Vivid durum wheat is adapted to the durum production area of the Canadian prairies. This conventional height durum wheat cultivar combines high grain yield potential with high grain pigment and protein concentrations and low grain cadmium. CDC Vivid is strong-strawed and has similar maturity and disease resistance to the current check cultivars. Source


Heat-related processing of cereal grains, legume seeds, and oil seeds could be used to improve nutrient availability in ruminants. However, different types of processing may have a different impact on intrinsic structure of tissues. To date, there is little research on structure changes after processing within intact tissues. The synchrotron-based molecular imaging technique enables us to detect inherent structure change on a molecular level. The objective of this study was to visualize tissue of black-type canola (Brassica) seed with a thick seed coat after heat-related processing in a chemical way using the synchrotron imaging technique. The results showed that the chemical images of protein amides were obtained through the imaging technique for the raw, wet, and dry heated black type of canola seed tissues. It seems that different types of processing have a different impact on the protein spectral profile in the black type of canola tissues. Wet heating had a greater impact on the protein α-helix to β-sheet ratio than dry heating. Both dry and wet heating resulted in different patterns in amide I, the second derivative, and FSD spectra. However, the exact differences in the tissue images are relatively difficult to be obtained through visual comparison. Future studies should focus on (1) comparing the response and sensitivity of canola seeds to various processing methods between the yellow-type and black-type of canola seeds; (2) developing a sensitive method to compare the image difference between tissues and between treatments; (3) developing a method to link images to nutrient digestion, and (4) revealing how structure changes affect nutrient absorption in humans and animals. © 2013 American Chemical Society. Source


Wu F.-X.,University of Saskatchewan
IEEE Transactions on Circuits and Systems I: Regular Papers | Year: 2012

Recently nonlinear differential equations with time delays have been proposed to model genetic regulatory networks, which provide a powerful tool for understanding gene regulatory processes in living organisms. In this paper we study the stability and bifurcation of a class of genetic regulatory networks with ring topology and multiple time delays at its equilibrium state. We first present necessary and sufficient conditions for delay-independently local stability of such genetic regulatory networks in the parameter space. Then we investigate their bifurcation when such networks lose their stability. Although such networks may have multiple delays and different connection strengths among individual nodes, their stability and bifurcation depends on the sum of all time delays among all elements (including both mRNAs and proteins) and the product of the connection strengths between all elements. An autoregulatory network and a repressilatory network are employed to illustrate the theorems developed in this study. © 2012 IEEE. Source


Gagnon K.B.,Vanderbilt University | Gagnon K.B.,University of Saskatchewan
Cellular Physiology and Biochemistry | Year: 2012

Cell motility is dependent on a coordinated reorganization of the cytoskeleton, membrane recycling, and focal adhesion to the extracellular matrix. Each of these cellular processes involves re-distribution of cell water, which is facilitated by the transport of inorganic ions (with obligatory water movement). Scratch-wound healing assays of Wistar C6 glioblastoma cells demonstrated cell motility in advance of cell proliferation. Although bumetanide inhibition of Na-K-2Cl cotransport activity did not affect cell motility, treatment of glioma cells with furosemide to inhibit K-Cl cotransport activity prevented ∼75% of wound closure in a reversible reaction. Genetic silencing of KCC3 with short hairpin interfering RNA reduced protein expression by 40-60%, K+ influx by ∼50%, and cell motility by ∼50%. Appearance of KCC1 mRNA and KCC3 mRNA at 25 PCR cycles versus KCC4 mRNA at 35 PCR cycles, suggests more KCC1/KCC3 expression in both primary rat astrocytes and C6 glioma cells. Altogether, these experiments suggest that the presence/function of multiple isoforms of the Na+-independent K-Cl cotransporter may have a role in glioma cell motility. © 2012 S. Karger AG, Basel. Source


Ponce-Coria J.,Vanderbilt University | Gagnon K.B.,University of Saskatchewan | Delpire E.,Vanderbilt University
American Journal of Physiology - Cell Physiology | Year: 2012

X-ray crystallography of the catalytic domain of oxidative stress response 1 (OSR1) has provided evidence for dimerization and domain swapping. However, the functional significance of dimer formation or domain swapping has yet to be addressed. In this study, we used nine glutamine residues to link the carboxyl end of one SPAK (related Ste20 kinase) monomer to the amino end of another SPAK monomer to assess the role of kinase monomers versus dimers in Na-K-2Cl cotransporter 1 (NKCC1) activation. Transport studies in Xenopus laevis oocytes show that forcing dimerization of two wild-type SPAK molecules results in cotransporter activation when calcium-binding protein 39 (Cab39) is coexpressed, indicating that the presence of Cab39 can bypass the upstream phosphorylation requirement of SPAK normally associated with kinase activation. We determined that monomers are the functional units of the kinase as concatamers consisting of an active and various inactive monomers were still functional. Furthermore, we found that two different nonfunctional SPAK mutants could be linked together in a concatamer and activated, presumably by domain swapping, indicating that dimerization and domain swapping are both important components of kinase activation. Finally, we demonstrate rescue of a nonfunctional SPAK mutant by domain swapping with wild-type OSR1, indicating that heterodimers of the two Ste20-related kinases are possible and therefore potentially relevant to the regulation of NKCC1 activity. © 2012 the American Physiological Society. Source


Natcher D.C.,University of Saskatchewan
Arctic | Year: 2013

An inventory of the nominal representation of men and women on northern co-management boards in the Yukon, Northwest Territories, and Nunavut identified a total of 34 co-management boards. Of their total of 210 members, 176 (84%) were males and 34 (16%) were females. Nine boards were composed exclusively of men, and 18 boards had only a single female representative. The land and resource management regimes created through the settlement of comprehensive land claims have afforded Aboriginal governments equitable representation in co-management but have not promoted gender equity in board membership. © The Arctic Institute of North America. Source


Gh Popescu B.F.,University of Saskatchewan | Gh Popescu B.F.,Cameco Neuroscience Research Center | Lucchinetti C.F.,Mayo Medical School
BMC Neurology | Year: 2012

Although historically considered a disease primarily affecting the white matter of the central nervous system, recent pathological and imaging studies have established that cortical demyelination is common in multiple sclerosis and more extensive than previously appreciated. Subpial, intracortical and leukocortical lesions are the three cortical lesion types described in the cerebral and cerebellar cortices of patients with multiple sclerosis. Cortical demyelination may be the pathological substrate of progression, and an important pathologic correlate of irreversible disability, epilepsy and cognitive impairment. Cortical lesions of chronic progressive multiple sclerosis patients are characterized by a dominant effector cell population of microglia, by the absence of macrophagic and leukocytic inflammatory infiltrates, and may be driven in part by organized meningeal inflammatory infiltrates. Cortical demyelination is also present and common in early MS, is topographically associated with prominent meningeal inflammation and may even precede the appearance of classic white matter plaques in some MS patients. However, the pathology of early cortical lesions is different than that of chronic MS in the sense that early cortical lesions are highly inflammatory, suggesting that neurodegeneration in MS occurs on an inflammatory background and raising interesting questions regarding the role of cortical demyelination and meningeal inflammation in initiating and perpetuating the disease process in early MS. © 2012 Gh Popescu and Lucchinetti; licensee BioMed Central Ltd. Source


Pierce C.W.,University of Saskatchewan
Canadian Journal of Cardiology | Year: 2010

A case of an 85-year-old woman with gradually progressive but severe dyspnea is reported. A thorough workup disclosed platypnea-orthodeoxia syndrome associated with right-to-left shunting through a patent foramen ovale, in the presence of several other recognized risk factors, despite the absence of significant pulmonary hypertension. Successful percutaneous transcatheter closure of the intracardiac defect resulted in resolution of the syndrome. © 2010 Pulsus Group Inc. All rights reserved. Source


Viju C.,Carleton University | Kerr W.A.,University of Saskatchewan
Energy Policy | Year: 2013

This paper examines the biofuels industry from a policy and international trade perspective. Across the globe there are two main public policy objectives driving the development of biofuels industries-improving energy security and reducing global warming. The US and Canadian governments have respectively fostered biofuels industries for these reasons. As biofuels industries will not be financially viable without government support in the foreseeable future, government policies can be interpreted as taking options on the future. A theoretical model is developed using option value theory to determine whether the same governmental policy (subsidization) can lead to different levels of optimal subsidies in each country, where the subsidy policy is driven by two distinct motivating factors. If the reason subsidy levels differ is structural, the likelihood of a trade dispute arising increases. © 2013 Elsevier Ltd. Source


Bordetella bronchiseptica (Bb) has long been causally associated with respiratory disease in dogs. Parenteral and intranasal vaccines for this pathogen have been in common use since their development in the late 1970s and early 1980s and recently a commercial oral Bb vaccine has become available. Overall, the literature (comprising experimental infection models and field studies) documents the efficacy of these vaccines in stimulating disease-sparing mucosal and systemic immune responses that can be associated with reduced growth of Bb in vivo. However, many of the published studies are limited by flaws in experimental design, most notably a failure to consider the biological and statistical implications of the 'pen effect'. Many questions related to the longevity of vaccine induced immunity against Bb and the impact of natural exposure on herd immunity remain unanswered. © 2015 Elsevier Ltd. Source


Leslie W.D.,University of Manitoba | Lix L.M.,University of Saskatchewan
Journal of Clinical Densitometry | Year: 2010

A simplified (semiquantitative) approach developed by the Canadian Association of Radiologists and Osteoporosis Canada (denoted as CAROC) for absolute fracture risk assessment incorporates age, sex, prior fragility fracture, and systemic corticosteroid use, together with bone mineral density (BMD) to define absolute fracture risk. The CAROC system has been shown to predict fracture rates in women referred for clinical BMD testing, but it is uncertain how this system performs in routine clinical practice in men who are much less likely to undergo BMD testing with potential for referral biases. Thirty-six thousand seven hundred and thirty women and 2873 men aged 50 yr or older at the time of baseline BMD testing were identified in a database containing all clinical dual-energy X-ray absorptiometry test results for the Province of Manitoba, Canada. Population-based health service records from 1987 to 2008 were assessed for fracture codes and medication use. Fracture risk under the CAROC model was categorized as low (<10%), moderate (10-20%), or high (>20%). Ten-year fracture risk estimated by the Kaplan-Meier method showed the same gradient in observed fracture risk for men and women. Despite evidence of greater referral bias in men resulting in a higher rate of clinical risk factors, the performance of the prediction algorithm was not affected. © 2010 The International Society for Clinical Densitometry. Source


Gober P.,University of Saskatchewan | Gober P.,Arizona State University | Wheater H.S.,National Water Research Institute
Hydrology and Earth System Sciences | Year: 2014

While there is a popular perception that Canada is a water-rich country, the Saskatchewan River basin (SRB) in Western Canada exemplifies the multiple threats to water security seen worldwide. It is Canada's major food-producing region and home to globally significant natural resource development. The SRB faces current water challenges stemming from (1) a series of extreme events, including major flood and drought events since the turn of the 21st century, (2) full allocation of existing water resources in parts of the basin, (3) rapid population growth and economic development, (4) increasing pollution, and (5) fragmented and overlapping governance that includes the provinces of Alberta, Saskatchewan, and Manitoba, various Federal and First Nations responsibilities, and international boundaries. The interplay of these factors has increased competition for water across economic sectors and among provinces, between upstream and downstream users, between environmental flows and human needs, and among people who hold different values about the meaning, ownership, and use of water. These current challenges are set in a context of significant environmental and societal change, including widespread land modification, rapid urbanization, resource exploitation, climate warming, and deep uncertainties about future water supplies. We use Sivapalan et al.'s (2012) framework of socio-hydrology to argue that the SRB's water security challenges are symptoms of dynamic and complex water systems approaching critical thresholds and tipping points. To Sivapalan et al.'s (2012) emphasis on water cycle dynamics, we add the need for governance mechanisms to manage emergent systems and translational science to link science and policy to the socio-hydrology agenda. © Author(s) 2014. Source


Ferguson G.,University of Saskatchewan | Gleeson T.,McGill University
Nature Climate Change | Year: 2012

Climate change and human population growth are expected to have substantial impacts on global water resources throughout the twenty-first century. Coastal aquifers are a nexus of the world's oceanic and hydrologic ecosystems and provide a water source for the more than one billion people living in coastal regions. Saltwater intrusion caused by excessive groundwater extraction is already impacting diverse regions of the globe. Synthesis studies and detailed simulations have predicted that rising sea levels could negatively impact coastal aquifers through saltwater intrusion and/or inundation of coastal regions. However, the relative vulnerability of coastal aquifers to groundwater extraction and sea-level rise has not been systematically examined. Here we show that coastal aquifers are more vulnerable to groundwater extraction than to predicted sea-level rise under a wide range of hydrogeologic conditions and population densities. Only aquifers with very low hydraulic gradients are more vulnerable to sea-level rise and these regions will be impacted by saltwater inundation before saltwater intrusion. Human water use is a key driver in the hydrology of coastal aquifers, and efforts to adapt to sea-level rise at the expense of better water management are misguided. © 2012 Macmillan Publishers Limited. All rights reserved. Source


Zhang W.J.,East China University of Science and Technology | Zhang W.J.,University of Saskatchewan | Van Luttervelt C.A.,Technical University of Delft
CIRP Annals - Manufacturing Technology | Year: 2011

Resilience often refers to a property of social and ecological systems. Recently, resilience is applied to engineered systems, referring to their capability to recover their functions after partial damage to lead to successes from failures. In this paper, the concept of engineering resilience is revisited and clarified. A new definition of the general production system is proposed, upon which the concept of the resilient manufacture system (RMS) is proposed. Furthermore, four guidelines for design and management of the RMS are proposed. Examples are discussed to illustrate the applications of these guidelines toward the RMS. © 2011 CIRP. Source


Rahimi S.,University of Saskatchewan
International Journal of Psychoanalysis | Year: 2013

I am my own twin, Always with me, same as me, and always watching me! From interview with a psychotic patient Every man carries with him through life a mirror, as unique and impossible to get rid of as his shadow W.H. Auden, 1989, p.93 I cannot urge you too strongly to a meditation on optics. Jacques Lacan, 1991, p.76 This paper outlines the basic arguments for a reading of the notion of the uncanny that draws on direct and metaphorical significances of the ocular in the development of human ego. It is argued that a specular-oriented reading of the uncanny as made possible through Lacan's model for ego development introduces a significant analytic device capable of explaining diverse features of the uncanny experience that escaped the traditional phallic/castration-based reading. To examine this claim, evidence is presented from a number of contexts to demonstrate how uncanny experiences are typically constructed through and associated with themes and metaphors of vision, blindness, mirrors and other optical tropes. Evidence is also presented from a historical point of view to demonstrate the strong presence of ocular and specular themes, devices and associations in a tradition of literary and psychological writing out of which the notion of 'the uncanny' (including Freud's own formulation) emerged. It is demonstrated that the main instances of the uncanny, such as doppelgangers, ghosts, déjà vu, alter egos, self-alienations and split personhoods, phantoms, twins, living dolls and many more in the list of 'things of terror' typically share two important features: they are closely tied with visual tropes, and they are variations on the theme of doubling. It is then argued that both of these features are integrally associated with the developmental processes of ego formation and self-identity, thus explaining the strong association of the uncanny accounts and experiences with ocular and specular motifs and metaphors. © 2013 Institute of Psychoanalysis. Source


Wu Y.,University of Saskatchewan
Journal of Nucleic Acids | Year: 2012

Helicases are enzymes that use ATP-driven motor force to unwind double-stranded DNA or RNA. Recently, increasing evidence demonstrates that some helicases also possess rewinding activity - in other words, they can anneal two complementary single-stranded nucleic acids. All five members of the human RecQ helicase family, helicase PIF1, mitochondrial helicase TWINKLE, and helicase/nuclease Dna2 have been shown to possess strand-annealing activity. Moreover, two recently identified helicases - HARP and AH2 have only ATP-dependent rewinding activity. These findings not only enhance our understanding of helicase enzymes but also establish the presence of a new type of protein: annealing helicases. This paper discusses what is known about these helicases, focusing on their biochemical activity to zip and unzip double-stranded DNA and/or RNA, their possible regulation mechanisms, and biological functions. © 2012 Yuliang Wu. Source


Logan D.C.,University of Saskatchewan
Seminars in Cell and Developmental Biology | Year: 2010

The higher plant chondriome is highly dynamic both in terms of the morphology and velocity of individual mitochondria within any given cell. Plant mitochondrial dynamics is a relatively new area of research, but one that has developed considerably over the early years of this century due to the generation of mitochondrially targeted fluorescent protein constructs and stably transformed lines. Several putative members of the plant mitochondrial division apparatus have been identified, but no genes have been identified as being involved in mitochondrial fusion. Despite the highly dynamic nature of plant mitochondria there is little specific scientific evidence linking mitochondrial dynamics to organelle and cell function. Two exceptions to this are the changes in mitochondrial dynamics that are early events during the induction of cell death programmes, and the extensive mitochondrial fusion that occurs before cytokinesis, although in both cases the role(s) of these events are a matter for conjecture. © 2010 Elsevier Ltd. Source


Zhang W.J.,University of Saskatchewan | Lin Y.,Northeastern University
Enterprise Information Systems | Year: 2010

Resilience engineering is an emerging discipline. In this article, we discuss the concept of resilience and resilience engineering in light of its distinct identity. We propose the principle of design of resilient systems. Then, we outline how these design principles can be applied to the enterprise information system to make it more resilient. This leads to a proposed architecture of resilient enterprise information systems. © 2010 Taylor & Francis. Source


Ludwig S.A.,University of Saskatchewan
Knowledge-Based Systems | Year: 2010

Knowledge engineering is a discipline concerned with constructing and maintaining knowledge bases to store knowledge of various domains and using the knowledge by automated reasoning techniques to solve problems in domains that ordinarily require human logical reasoning. Therefore, the two key issues in knowledge engineering are how to construct and maintain knowledge bases, and how to reason out new knowledge from known knowledge effectively and efficiently. The objective of this paper is the comparison and evaluation of a Deductive Database system (ConceptBase) with a Semantic Web reasoning engine (Racer). For each system a knowledge base is implemented in such a way that a fair comparison can be achieved. Issues such as documentation, feasibility, expressiveness, complexity, distribution, performance and scalability are investigated in order to explore the advantages and shortcomings of each system. © 2010 Elsevier B.V. All rights reserved. Source


Razavi S.,University of Saskatchewan | Tolson B.A.,University of Waterloo
Water Resources Research | Year: 2013

Long periods of hydrologic data records have become available in many watersheds around the globe. Hydrologic model calibration on such long, full-length data periods is typically deemed the most robust approach for calibration but at larger computational costs. Determination of a representative short period as a surrogate of a long data period that sufficiently embeds its information content is not trivial and is a challenging research question. The representativeness of such a short period is not only a function of data characteristics but also model and calibration error function dependent. Unlike previous studies, this study goes beyond identifying the best surrogate data period to be used in model calibration and proposes an efficient framework that calibrates the hydrologic model to full-length data while running the model only on a short period for the majority of the candidate parameter sets. To this end, a mapping system is developed to approximate the model performance on the full-length data period based on the model performance for the short data period. The basic concepts and the promise of the framework are demonstrated through a computationally expensive hydrologic model case study. Three calibration approaches, namely calibration solely to a surrogate period, calibration to the full period, and calibration through the proposed framework, are evaluated and compared. Results show that within the same computational budget, the proposed framework leads to improved or equal calibration performance compared to the two conventional approaches. Results also indicate that model calibration solely to a short data period may lead to a range of performances from poor to very well depending on the representativeness of the short data period which is typically not known a priori. © 2013. American Geophysical Union. All Rights Reserved. Source


Butler S.L.,University of Saskatchewan
Physics of the Earth and Planetary Interiors | Year: 2012

When a system of partial melt is subjected to an externally driven strain-rate, an instability can occur whereby bands of low and high porosity form. Theory and numerical simulations have shown that if the matrix viscosity is isotropic and strain-rate independent, the bands grow fastest when parallel to the direction of maximum compression of the externally imposed flow. However, experiments indicate that bands form at angles that differ by roughly 25° from the direction of maximum compression even when the matrix viscosity is strain-rate independent. Recently, Takei and Holtzman (2009c) have argued that the matrix viscosity is likely to be anisotropic when partial melt is present because of the anisotropic arrangement of melt at the grain scale. These authors also presented a theoretical expression for the stress tensor in the presence of this anisotropy and a linear theory of band formation that indicated that bands would form at angles that are in accord with the results of experiments. In this contribution, I present the results of linear theory and full nonlinear simulations of band formation under simple shear with anisotropic viscosity. I show that, even when the viscosity is strain-rate independent, the resulting bands form at low angles in accord with experiments if the anisotropy reflects a distribution of melt in pockets aligned parallel to the direction of maximum compression. If instead the anisotropy represents melt that is aligned at low angles to the shear plane, as seen in highly deformed experiments, the melt bands rapidly rotate to high angles. In that case, another mechanism is required to maintain the bands at low angles. The effects of buoyant melt are also investigated and bands are shown to grow at the same rate as when buoyancy is absent, but with an additional secondary preferred orientation. © 2012 Elsevier B.V.. Source


Kalynych S.,McGill University | Morona R.,University of Adelaide | Cygler M.,McGill University | Cygler M.,University of Saskatchewan
FEMS Microbiology Reviews | Year: 2014

The discovery that the surfaces of Gram-negative bacteria often carry unique polysaccharide signatures pre-dates most seminal discoveries of molecular biology and biochemistry of the 20th century. The O-antigen component of the lipopolysaccharide has been one of the most intensely studied bacterial polysaccharide surface structures for over 80 years. Yet, many questions about the mechanism of biosynthesis of the O-antigen and its transport to the cell surface remain unanswered. In this review we provide an overview of how the molecular basis of the O-antigen assembly and trafficking were unraveled in a historical context. We pay particular attention to the emergence of novel technological approaches and how they fueled the elucidation of the O-antigen maturation process. Moreover, we provide a brief perspective on the biosynthesis of enterobacterial common antigen and underline the similarities and differences between the pathways used to assemble these two surface polysaccharides. Finally, we highlight key discoveries that led to the understanding of the mechanistic basis of bacteriophage-induced O-antigen modifications. We place special emphasis on the regulation of the length of O-antigen polymers and provide a detailed overview of the models explaining the O-antigen length determination. Finally, we highlight outstanding questions that need to be addressed both structurally and functionally to advance our understanding of the O-antigen assembly, trafficking and export within cellular and molecular contexts. This review provides a historical perspective of how the molecular basis of the O-antigen assembly was elucidated, and to underscore some of the most intriguing questions that remain to be addressed. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved. Source


Olver M.E.,University of Saskatchewan | Lewis K.,Private Practice | Wong S.C.P.,University of Nottingham
Personality Disorders: Theory, Research, and Treatment | Year: 2013

The relationships of psychopathy, therapeutic change, and violent recidivism were examined in a sample of 152 high-risk violent offenders treated in a high-intensity violence reduction program at the Regional Psychiatric Centre (RPC) in Saskatoon, SK. The Violence Risk Scale (VRS; Wong & Gordon, 1999-2003) and Psychopathy Checklist-Revised (PCL-R; Hare, 1991, 2003) were rated on the sample. As an extension on a prior psychometric study of the VRS (Lewis, Olver, & Wong, 2012), the associations of therapeutic change scores, obtained from pre- and posttreatment ratings of VRS dynamic items, and violent recidivism were examined among high-risk psychopathic offenders (mean PCL-R >25) over approximately 5 years' follow-up. Positive therapeutic change correlated negatively with the PCL-R, particularly Factor 1 and the Affective facet, and was significantly associated with reductions in violent recidivism after controlling for psychopathy. The association of change to violent outcome decreased, however, when controlling for the Affective facet. Taken together, the present results suggest that risk-related treatment changes demonstrated by high-risk psychopathic offenders can be predictive of reductions in violent recidivism, and that reliable measurements of therapeutic change may be informative about treatment outcome in a high-risk violent offender group. © 2012 American Psychological Association.. Source


Von Tigerstrom B.,University of Saskatchewan
Food and Drug Law Journal | Year: 2011

In an ongoing dispute, FDA asserts that autologous cultured stem cells used in treatments for orthopedic conditions are drugs and biological products subject to licensing and good manufacturing practice requirements, while the company providing the treatments claims FDA has no authority over its activities. This article uses the dispute as a focal point to explore current issues relating to the regulation of innovative stem cell-based products, including the impact of regulation on access to new treatments, the role of other oversight mechanisms, the particular challenges of autologous stem cell products and the scope of existing flexibilities in the regulatory framework. Source


Adams G.P.,University of Saskatchewan | Ratto M.H.,Austral University of Chile
Animal Reproduction Science | Year: 2013

Ovulation in mammals involves pulsatile release of GnRH from the hypothalamus into the hypophyseal portal system with subsequent release of LH from the anterior pituitary into systemic circulation. Elevated circulating concentrations of LH induce a cascade of events within the mature follicle, culminating in follicle rupture and evacuation. The broad classification of species as either spontaneous or induced ovulators is based on the type of stimulus responsible for eliciting GnRH release from the hypothalamus. In spontaneously ovulating species (e.g., human, sheep, cattle, horse, pigs), release of GnRH from the hypothalamus is triggered when, in the absence of progesterone, systemic estradiol concentrations exceed a threshold. In induced ovulators (e.g., rabbits, ferrets, cats, camelids), release of GnRH is contingent upon copulatory stimuli; hence, ovulation is not a regular cyclic event. Since a classic 1970 Peruvian study, dogma has maintained that physical stimulation of the genitalia during copulation is the primary trigger for inducing ovulation in alpacas and llamas. Exciting results of recent studies, however, provide direct evidence for the existence of an ovulation-inducing factor (OIF) in semen, and compel us to re-examine the mechanism of ovulation in both induced and spontaneous ovulators. Ovulation-inducing factor in seminal plasma is a potent stimulant of LH secretion, ovulation and luteal gland development, and acts via a systemic rather than a local route. OIF is a protein molecule that is resistant to heat and enzymatic digestion with proteinase K. It has a molecular mass of 14. kDa, and may be part of a larger protein complex or pro-hormone. The effect of OIF is dose-related and evident at physiologically relevant doses (i.e., as little as 1/100th that present in the ejaculate), and is mediated, in whole or in part, at the level of the hypothalamus in vivo. The factor exists in the seminal plasma of every species in which it has been examined thus far, including Bactrian camels, alpacas, llamas, cattle, horses, pigs, and koalas. Seminal plasma OIF does not appear to be a phylogenetic vestige in spontaneous ovulators since it (1) induced ovulation in pre-pubertal mice, (2) altered ovarian follicular wave dynamics in cows, and (3) elicited LH release in vitro from primary pituitary cell cultures of rats, mice, guinea pigs, rabbits, llamas and cows. © 2012 Elsevier B.V. Source


Ndisang J.F.,University of Saskatchewan
Mediators of Inflammation | Year: 2010

Diabetes and obesity are chronic conditions associated with elevated oxidative/inflammatory activities with a continuum of tissue insults leading to more severe cardiometabolic and renal complications including myocardial infarction and end-stage-renal damage. A common denominator of these chronic conditions is the enhanced the levels of cytokines like tumour necrosis factor-alpha (TNF- ), interleukin (IL-6), IL-1 and resistin, which in turn activates the c-Jun-N-terminal kinase (JNK) and NF- B pathways, creating a vicious cycle that exacerbates insulin resistance, type-2 diabetes and related complications. Emerging evidence indicates that heme oxygenase (HO) inducers are endowed with potent anti-diabetic and insulin sensitizing effects besides their ability to suppress immune/inflammatory response. Importantly, the HO system abates inflammation through several mechanisms including the suppression of macrophage-infiltration and abrogation of oxidative/inflammatory transcription factors like NF- B, JNK and activating protein-1. This review highlights the mechanisms by which the HO system potentiates insulin signalling, with particular emphasis on HO-mediated suppression of oxidative and inflammatory insults. The HO system could be explored in the search for novel remedies against cardiometabolic diseases and their complications. Copyright © 2010 Joseph Fomusi Ndisang. Source


Kelly D.M.,University of Saskatchewan
Animal Cognition | Year: 2010

Successful navigation within an environment requires that the traveler establish the correct heading-a process referred to as orienting. Many studies have now shown that humans and non-human animals can use the geometric properties of an enclosure to orient. In the present study, two groups of Clark's nutcrackers (Nucifraga columbiana) were trained, in a reference memory task, to find food hidden in one of four containers arranged to form a rectangular array. One group had unique objects placed next to each of the containers, whereas the second group had identical objects placed next to each of the containers. Here, I show for the first time that for the Clark's nutcracker, the distinctive properties of these objects enhanced the encoding of the array's geometry compared to the learning of geometric properties from an array of identical objects, which remained at chance after substantial amounts of training. Subsequent transformation tests showed that an object not associated with reward, but sharing the same geometric properties as the correct object, may have had inhibitory qualities. Furthermore, by systematically removing objects from the array, I show that although nutcrackers encoded the geometry of the array, they did not encode a complete featural representation of the objects within the array. © Springer-Verlag 2009. Source


Chen H.-X.,Beijing University of Technology | Chen H.-X.,Beihang University | Chen W.,University of Saskatchewan | Liu X.,Lanzhou University | And 2 more authors.
Physics Reports | Year: 2016

In the past decade many charmonium-like states were observed experimentally. Especially those charged charmonium-like Zc states and bottomonium-like Zb states cannot be accommodated within the naive quark model. These charged Zc states are good candidates of either the hidden-charm tetraquark states or molecules composed of a pair of charmed mesons. Recently, the LHCb Collaboration discovered two hidden-charm pentaquark states, which are also beyond the quark model. In this work, we review the current experimental progress and investigate various theoretical interpretations of these candidates of the multiquark states. We list the puzzles and theoretical challenges of these models when confronted with the experimental data. We also discuss possible future measurements which may distinguish the theoretical schemes on the underlying structures of the hidden-charm multiquark states. © 2016 Elsevier B.V.. Source


Clark L.F.,University of Saskatchewan
Science and Public Policy | Year: 2013

The interpretation of risk in governance frameworks for genetically modified (GM) foods is an important component of their design and function. This paper develops the concept of a risk frame to better understand how perceptions of risk, uncertainty, and authority over evidence are considered in governance frameworks for GM foods. It develops a typology of risk frames: the proof of harm, precautious and precaution through experience risk frames. The 'precaution through experience' risk frame is an emergent concept offering possible avenues beyond current regulatory standoffs by incorporating both scientific and socio-economic perspectives of risk in deepened deliberative settings. The paper uncovers how varying interpretations of uncertainty and acceptable levels of risk associated with innovative technologies influence the development of public policy within regulatory frameworks for biotechnology. © The Author 2013. Published by Oxford University Press. All rights reserved. Source


Barrett M.J.,University of Saskatchewan
Policy Sciences | Year: 2013

Although it can be challenging, engagement with diverse knowledges and knowledge systems can lead to better decisions. The purpose of this paper is to open a dialog about transrational (spiritual) knowing within socio-ecological decision-making with two common interest goals in mind: (1) making better decisions for long-term sustainability for all beings, including those who are human and those who are not, and (2) animating processes for decision-making that are inclusive of ways of knowing of all peoples. I suggest that serious consideration of transrational knowing is critical to addressing the incommensurability of Western and Indigenous knowledge systems, and meeting the identified goals. © 2013 Springer Science+Business Media New York. Source


Beland D.,University of Saskatchewan | Orenstein M.A.,Northeastern University
Global Social Policy | Year: 2013

The study of how ideas and discourse evolve within international organizations is one of the most important frontiers of global social policy theory. Setting forth an ideational approach to understanding their behavior, the article argues that international organizations are more open systems than most realists and structuralists believe. Their constantly evolving discourse and ideas can directly impact domestic policy. In order to stress this reality, drawing on the case of pension privatization, the article compares these organizations with ideologically driven domestic think tanks which, as far as pension privatization is concerned, have proved much more rigid in their policy prescriptions than the World Bank and other international organizations traditionally associated with the global pension privatization campaign. © The Author(s) 2013. Source


Wisniewski M.,U.S. Department of Agriculture | Gusta L.,University of Saskatchewan | Neuner G.,University of Innsbruck
Environmental and Experimental Botany | Year: 2014

Freeze avoidance has evolved in plants in response to selection pressures brought about by exposure to freezing temperatures. It is a multifaceted adaptive mechanism with many attributes. Despite the prevalence of freeze avoidance as an adaptive mechanism, little research has been devoted in recent times to understanding the underlying mechanisms and regulation of freeze avoidance. Therefore, there is no shortage of questions that need to be addressed. Inherent in understanding how plants respond to freezing temperatures is the need to also understand the properties of water at different temperatures and how the interaction of water with biological substances affects these properties. This review provides an overview of the subject of biological ice nucleation and propagation and how various aspects of plant structure and composition can affect the freezing process. Deep supercooling of plant tissues represents the most extreme example of freeze avoidance. The potential role of anti-nucleating substances in defining the ability to deep supercool is also discussed. The importance of studying intact plants in their natural environments is emphasized. Although, this adds a high degree of complexity to investigations, it is in this context that adaptive mechanisms have evolved and play a role in the biology and survival of plants. © 2013. Source


Ramakrishna G.,University of Saskatchewan | Malik O.P.,University of Calgary
Electric Power Systems Research | Year: 2010

Implementation of an adaptive power system stabilizer (APSS) and experimental studies are presented in this paper. The APSS consists of an adaptive linear element (ADALINE) based identifier that identifies the power system as a third-order discrete auto-regressive moving average (ARMA) model and a pole-shift controller. The ADALINE is modeled so that its weights have a one-to-one relationship with the ARMA model parameters. The weights are updated at each sampling interval to track the dynamic characteristics of the actual system. The on-line updated ARMA parameters are used in the PS control algorithm to calculate the new closed-loop poles of the system that are always inside the unit circle in the z-plane. The calculated control is such that it achieves regulation of the system to a constant setpoint in the shortest interval of time. Experimental studies on a physical model of power system verify that the proposed adaptive PSS effectively damps the oscillations and improves power system stability. © 2009 Elsevier B.V. All rights reserved. Source


Leduc A.O.H.C.,Federal University of Bahia | Munday P.L.,James Cook University | Brown G.E.,Concordia University at Montreal | Ferrari M.C.O.,University of Saskatchewan
Philosophical Transactions of the Royal Society B: Biological Sciences | Year: 2013

For many aquatic organisms, olfactory-mediated behaviour is essential to the maintenance of numerous fitness-enhancing activities, including foraging, reproduction and predator avoidance. Studies in both freshwater and marine ecosystems have demonstrated significant impacts of anthropogenic acidification on olfactory abilities of fish and macroinvertebrates, leading to impaired behavioural responses, with potentially far-reaching consequences to population dynamics and community structure. Whereas the ecological impacts of impaired olfactory-mediated behaviour may be similar between freshwater and marine ecosystems, the underlying mechanisms are quite distinct. In acidified freshwater, molecular change to chemical cues along with reduced olfaction sensitivity appear to be the primary causes of olfactory- mediated behavioural impairment. By contrast, experiments simulating future ocean acidification suggest that interference of high CO2 with brain neurotransmitter function is the primary cause for olfactory-mediated behavioural impairment in fish. Different physico-chemical characteristics between marine and freshwater systems are probably responsible for these distinct mechanisms of impairment, which, under globally rising CO2 levels, may lead to strikingly different consequences to olfaction. While fluctuations in pH may occur in both freshwater and marine ecosystems, marine habitat will remain alkaline despite future ocean acidification caused by globally rising CO2 levels. In this synthesis, we argue that ecosystem-specific mechanisms affecting olfaction need to be considered for effective management and conservation practices. © 2013 The Author(s) Published by the Royal Society. All rights reserved. Source


Prasad K.,University of Saskatchewan
Current Pharmaceutical Biotechnology | Year: 2010

Many natural products, including vitamin E, garlic, purpurogallin, flaxseed and its components [secoisolariciresinol diglucoside (SDG) and flax lignan complex (FLC)] and resveratrol have been reported to suppress hypercholesterolemic atherosclerosis. It is known that all of the drugs that suppress the development of atherosclerosis do not regress and/or slow the progression of atherosclerosis. To be of potential benefit in patients with established atherosclerosis, a drug should produce regression and/or slow the progression of atherosclerosis. In this review, the effects of vitamin E, SDG and FLC in the regression and slowing of progression of hypercholesterolemic atherosclerosis and their mechanisms have been described. The effectiveness of vitamin E in patients with established coronary disease is very controversial. However, in experimental animal controlled studies, vitamin E does not regress or slow the progression of hypercholesterolemic atherosclerosis. The mechanisms of the ineffectiveness of vitamin E in regression and slowing of progression of atherosclerosis have been discussed. SDG is effective in slowing the progression of atherosclerosis and partially effective in regression of hypercholesterolemic atherosclerosis. These effects are associated with reduction in oxidative stress. FLC does not regress hypercholesterolemic atherosclerosis but slows the progression of hypercholesterolemic atherosclerosis. Slowing of progression is associated with reduction on oxidative stress. In conclusion, vitamin E does not regress or slow the progression of established atherosclerosis. SDG slows the progression and regresses established atherosclerosis. FLC does not regress but slows the progression of established atherosclerosis. Source


Leary S.C.,University of Saskatchewan
Antioxidants and Redox Signaling | Year: 2010

Reversible changes in the redox state of cysteine residues represent an important mechanism with which to regulate protein function. In mitochondria, such redox reactions modulate the localization or activity of a group of proteins, most of which function in poorly defined pathways with essential roles in copper delivery to cytochrome c oxidase (COX) during holoenzyme biogenesis. To date, a total of 8 soluble (COX17, COX19, COX23, PET191, CMC1-4) and 3 integral membrane (COX11, SCO1, SCO2) accessory proteins with cysteine-containing domains that reside within the mitochondrial intermembrane space (IMS) have been identified in yeast, all of which have human orthologues. Compelling evidence from studies of COX17, SCO1, and SCO2 argues that regulation of the redox state of their cysteines is integral to their metallochaperone function. Redox also appears to be crucial to the regulation of a SCO-dependent, mitochondrial signaling pathway that modulates the rate of copper efflux from the cell. Here, I review our understanding of redox-dependent modulation of copper delivery to COX and IMS-localized copper-zinc superoxide dismutase (SOD1) during the maturation of each enzyme, and discuss how this in turn may serve to functionally couple mitochondrial copper handling pathways with those localized elsewhere in the cell to regulate cellular copper homeostasis. © 2010, Mary Ann Liebert, Inc. Source


Livingston A.,University of Saskatchewan
Handbook of Experimental Pharmacology | Year: 2010

The biggest challenge to the use of analgesic agents in animals is the determination of the efficacy of these agents. In humans, the verbal communication of the alleviation of pain is fundamental to the effective use of analgesics. In animals, the lack of verbal communication not only confounds the diagnosis and characterisation of the experience of pain, but also challenges the evaluation of the analgesic therapy. As animals possess the same neuronal pathways and neurotransmitter receptors as humans, it seems reasonable to expect that their perceptions of painful stimuli will be similar, and this is a basis for the use of laboratory animals for screening of analgesics for human use. However, as the evaluation in the laboratory animal tests is based mainly on behavioural responses, and although some physiological responses do occur, it is often difficult to separate these from stress responses. The use of behavioural responses to evaluate analgesics in a range of species is complicated by the fact that different species show different behaviours to a similar pain stimulus, and different pain stimuli produce different pain responses in the same species. Thus behaviours may be species- and pain-specific and this can complicate analgesic evaluation. As most animals possess similar neuronal mechanisms to humans for pain perception, it is not surprising that the standard human pain control strategies can be applied to animals. For instance, local anaesthetics, opioids, non-steroidal anti-inflammatory drugs (NSAIDs), as well as other analgesics used in humans are all found to be effective for animal use. Differences in metabolism and distribution between various species, as well as financial considerations in larger animals can affect efficacy and thus limit their use. In addition, the use of any drug in a species that may be intended for human consumption will be limited by residue considerations. The treatment of pain in animals presents many challenges, but the increasing public concerns regarding animal welfare will ensure that studies into the nature and control of animal pain will continue to have a high profile. © 2010 Springer-Verlag Berlin Heidelberg. Source


Hanninen H.,University of Helsinki | Tanino K.,University of Saskatchewan
Trends in Plant Science | Year: 2011

Climate warming has increased researchers' interest in plant phenology and its modelling. Although the main focus is on projections of accelerated springtime phenological events, also a further extension of the growing season by delayed growth cessation is often projected. However, ecophysiological studies indicate that, for boreal and temperate trees, such generalisations are precluded owing to differential climatic conditions and inter- and intraspecific genetic differences. The annual cycle of these trees is an integrated system, where one phase affects subsequent phases, resulting in delayed impacts, which are only partially addressed in current ecophysiological models. Here, we outline an updated integrated conceptual model of the annual cycle by identifying ecophysiological phenomena that are particularly significant under climate warming. © 2011 Elsevier Ltd. Source


Slagsvold T.,University of Oslo | Wiebe K.L.,University of Saskatchewan
Philosophical Transactions of the Royal Society B: Biological Sciences | Year: 2011

We briefly review the literature on social learning in birds, concluding that strong evidence exists mainly for predator recognition, song, mate choice and foraging. The mechanism of local enhancement may be more important than imitation for birds learning to forage, but the former mechanism may be sufficient for faithful transmission depending on the ecological circumstances. To date, most insights have been gained from birds in captivity. We present a study of social learning of foraging in two passerine birds in the wild, where we cross-fostered eggs between nests of blue tits, Cyanistes caeruleus and great tits, Parus major. Early learning causes a shift in the foraging sites used by the tits in the direction of the foster species. The shift in foraging niches was consistent across seasons, as showed by an analysis of prey items, and the effect lasted for life. The fact that young birds learn from their foster parents, and use this experience later when subsequently feeding their own offspring, suggests that foraging behaviour can be culturally transmitted over generations in the wild. It may therefore have both ecological and evolutionary consequences, some of which are discussed. © 2011 The Royal Society. Source


Bedard-Haughn A.,University of Saskatchewan
Canadian Journal of Soil Science | Year: 2011

This review examines the pedogenesis of Gleysolic soils, including how they affect and are affected by land use and climate change. In the Canadian System of Soil Classification, the Gleysolic Order includes all those soils with morphologic features that provide dominant physical evidence of oxidation-reduction processes or gleying. Gley features include dull coloured soil matrices and/or brightly coloured mottles, which arise due to periodic or permanently saturated conditions. Under saturated conditions, oxygen is rapidly depleted and alternative terminal electron acceptors (such as iron, Fe3+) are used by microorganisms in the decomposition of organic matter. Gleysolic soils are found throughout Canada, either in low-lying landscape positions in association with better-drained soil orders (e.g., Prairie Pothole region), or as the dominant soil type where topography and/or a slowly permeable substrate prolong the period of saturation (e.g., Clay Belt of northern Ontario and Quebec). These soils are often highly fertile agricultural land and are commonly drained for production, altering the soil-forming environment. Gleysolic soils have also been found to be potentially significant sources of greenhouse gas emissions due to high levels of denitrification and methanogenesis under their characteristic reducing conditions. Given their economic, ecologic, and environmental significance, further research is required to refine our understanding and classification of Gleysolic soils, particularly with respect to (1) how Gleysols are affected by human-or climate-change-induced changes to the drainage regime (either progressing towards reducing conditions or regressing to a non-redoximorphic state), (2) classification of carbonated and saline Gleysols, and (3) pseudogley versus groundwater Gleysols. Source


Zhang H.,University of Victoria | Shi Y.,University of Victoria | Saadat Mehr A.,University of Saskatchewan
Journal of Sound and Vibration | Year: 2011

In this paper, the design problem for non-fragile dynamic vibration absorbers (DVAs) is investigated. Due to the imprecision of the manufacturing process or the variation during the operation, uncertainty in the parameters of the DVA is unavoidable. The uncertainty may degrade the performance of the designed DVA or even deteriorate the system. Hence, it is practically demanding to propose a design method for a non-fragile DVA, i.e., when the parameters of the DVA vary in an admissible range, an expected vibration suppression level should be guaranteed. The uncertainty of the DVA is feasibly assumed to be norm-bounded. Then, the design problem for the DVA is converted into a static output feedback (SOF) control problem. Sufficient condition for the existence of the non-fragile DVA with a prescribed H∞ level is derived by using a bilinear matrix inequality (BMI). An iterative linear matrix inequality (ILMI) method is employed to solve the BMI condition. Finally, a design example is given to show the effectiveness of the proposed approach. © 2010 Elsevier Ltd. All rights reserved. Source


Samarasinghe S.,Lincoln University at Christchurch | Strickert G.,University of Saskatchewan
Environmental Modelling and Software | Year: 2013

Human systems need to be adaptive to the consequences of natural hazards. Public policy decisions on natural hazard mitigation can benefit from computational models that embody a comprehensive view of the system. Such models need to be transparent and integrate both expert and lay expert knowledge and experience in an efficient manner. By integrating hard and soft sciences within an overall systems framework, scientists, policy makers and communities can better understand how to improve adaptive capacity. We present a fuzzy cognitive map based Auto-Associative Neural Networks framework generated from a development mixed method integration (triangulation) for adaptive policy formulations. The specific policies relate to preparation for, response to, and recovery from earthquakes in mountainous ski-field environments - a case study chosen to highlight the framework. Three different data collection techniques - expert geomorphic assessments, semi-structured qualitative interviews with three stakeholder groups (experts and lay experts), and fuzzy cognitive maps (FCM) (node and arc maps of stakeholder perceptions) were employed. FCM were first analysed using Graph theory indices to determine map structure. Special attention was paid to subsequent processing of fuzzy cognitive maps (e.g., condensation and aggregation) with qualitative followed by quantitative means to simplify the FCM from the original total of 300 variables to 5 high-level themes to improve the efficacy of subsequent policy simulations. Specifically, the use of Self Organising Maps (SOM) to group concepts (condensation) and individual stakeholders (aggregation) into social group FCMs is a novel contribution to advancing FCM. In the process, SOM also enabled the embedment of nonlinear relationships inherent in the system in the simplified FCM allowing a platform for realistic and meaningful policy simulations based on collective perceptions. Specifically, each of the three simplified stakeholder group FCM and a total social group FCM was represented by Auto-Associative Neural Networks (AANN) which converts an FCM into a dynamical system that allows policy scenario simulations based on input from both expert and lay expert stakeholders. A policy scenario is the level of importance given to a set of concepts and their effects on the system behaviour as revealed by the simulations. We present the results from one of several policy simulations to highlight the effectiveness of the mixed-method integration leading to simplified-FCM based ANNN simulations. Results revealed the similarities and differences between stakeholder group responses in relation to the scenario analysed and how these formed collective responses in the total social group map. Furthermore, outcomes of group and total social group simulations could be interpreted from individual and group stakeholder FCMs giving credibility to the mixed-method approach. © 2012 Elsevier Ltd. Source


Bremner M.R.,University of Saskatchewan
Groups, Complexity, Cryptology | Year: 2011

This is a survey paper on algorithms that have been developed during the last 25 years for the explicit computation of the structure of an associative algebra of finite dimension over either a finite field or an algebraic number field. This constructive approach was initiated in 1985 by Friedl and Rónyai and has since been developed by Cohen, de Graaf, Eberly, Giesbrecht, Ivanyos, Küronya and Wales. I illustrate these algorithms with the case n = 2 of the rational semigroup algebra of the partial transformation semigroup P T n on n elements; this generalizes the full transformation semigroup and the symmetric inverse semigroup, and these generalize the symmetric group S n. © de Gruyter 2011. Source


Ward D.E.,University of Saskatchewan
Chemical Communications | Year: 2011

The strategic use of thiopyran templates to facilitate polypropionate synthesis was first demonstrated in Woodward's landmark total synthesis of erythromycin A in 1981 where the topology of a fused bicyclic system was exploited. In the ensuing three decades, various alternative strategic applications of thiopyran motifs to achieve key stereoselective transformations have emerged including, inter alia, unique substrates for chemoenzymatic syntheses, surrogates for 3-pentanone in enantioselective aldol reactions, and templates for enantiotopic group selective reactions. This review summarizes these developments. © 2011 The Royal Society of Chemistry. Source


Hersikorn B.D.,University of Saskatchewan | Smits J.E.G.,University of Calgary
Environmental Pollution | Year: 2011

The wet landscape approach to oil sands tailings reclamation in the Athabasca Oil Sands region involves creating wetlands from fluid tailings in mined-out pits. We measured time to metamorphosis, thyroid hormone status, and detoxification enzyme (EROD) induction in Wood frog (Lithobates sylvaticus) tadpoles raised on reclaimed oil sands wetlands of different ages [young (≤7 yr) vs. old (>7 yr)] and compared data with tadpoles raised on reference (control) wetlands. Metamorphosis was delayed or never occurred in tadpoles raised in young tailings; those exposed to older tailings developed similarly to those in reference wetlands. Thyroid hormone disruption likely played an important role in the metamorphosis delay as the T3:T4 ratio was lowest in tadpoles raised in young, tailings-affected wetlands. Our findings suggest tailings wetlands become less toxic with age, and that these amphibians will be able to complete their life cycle in tailing wetlands that have sufficiently detoxified with age. © 2010 Elsevier Ltd. All rights reserved. Source


Xie K.,Chongqing University | Billinton R.,University of Saskatchewan
Renewable Energy | Year: 2011

The electrical energy production and reliability benefits of a wind energy conversion system (WECS) at a specific site depend on many factors, including the statistical characteristics of the site wind speed and the design characteristics of the wind turbine generator (WTG) itself, particularly the cut-in, rated and cut-out wind speed parameters. In general, the higher the degree of the wind site matching with a WECS is, the more are the energy and reliability benefits. An electrical energy production and reliability benefit index designated as the Equivalent Capacity Ratio (ECR) is introduced in this paper. This index can be used to indicate the electrical energy production, the annual equivalent utilization time and the credit of a WECS, and quantify the degree of wind site matching with a WECS. The equivalent capacity of a WECS is modeled as the expected value of the power output random variable with the probability density function of the site wind speed. The analytical formulation of the ECR is based on a mathematical derivation with high accuracy. Twelve WTG types and two test systems are used to demonstrate the effectiveness of the proposed model. The results show that the ECR provides a useful index for a WTG to evaluate the energy production and the relative reliability performance in a power system, and can be used to assist in the determination of the optimal WTG type for a specific wind site. © 2011 Elsevier Ltd. Source


Leslie W.D.,University of Manitoba | Lix L.M.,University of Saskatchewan
Journal of Bone and Mineral Research | Year: 2011

The World Health Organization (WHO) Fracture Risk Assessment Tool (FRAX) computes 10-year probability of major osteoporotic fracture from multiple risk factors, including femoral neck (FN) T-scores. Lumbar spine (LS) measurements are not currently part of the FRAX formulation but are used widely in clinical practice, and this creates confusion when there is spine-hip discordance. Our objective was to develop a hybrid 10-year absolute fracture risk assessment system in which nonvertebral (NV) fracture risk was assessed from the FN and clinical vertebral (V) fracture risk was assessed from the LS. We identified 37,032 women age 45 years and older undergoing baseline FN and LS dual-energy X-ray absorptiometry (DXA; 1990-2005) from a population database that contains all clinical DXA results for the Province of Manitoba, Canada. Results were linked to longitudinal health service records for physician billings and hospitalizations to identify nontrauma vertebral and nonvertebral fracture codes after bone mineral density (BMD) testing. The population was randomly divided into equal-sized derivation and validation cohorts. Using the derivation cohort, three fracture risk prediction systems were created from Cox proportional hazards models (adjusted for age and multiple FRAX risk factors): FN to predict combined all fractures, FN to predict nonvertebral fractures, and LS to predict vertebral (without nonvertebral) fractures. The hybrid system was the sum of nonvertebral risk from the FN model and vertebral risk from the LS model. The FN and hybrid systems were both strongly predictive of overall fracture risk (p<.001). In the validation cohort, ROC analysis showed marginally better performance of the hybrid system versus the FN system for overall fracture prediction (p=.24) and significantly better performance for vertebral fracture prediction (p<.001). In a discordance subgroup with FN and LS T-score differences greater than 1 SD, there was a significant improvement in overall fracture prediction with the hybrid method (p=.025). Risk reclassification under the hybrid system showed better alignment with observed fracture risk, with 6.4% of the women reclassified to a different risk category. In conclusion, a hybrid 10-year absolute fracture risk assessment system based on combining FN and LS information is feasible. The improvement in fracture risk prediction is small but supports clinical interest in a system that integrates LS in fracture risk assessment. © 2011 American Society for Bone and Mineral Research. Copyright © 2011 American Society for Bone and Mineral Research. Source


Leslie W.D.,University of Manitoba | Morin S.N.,McGill University | Lix L.M.,University of Saskatchewan
Journal of Clinical Endocrinology and Metabolism | Year: 2012

Context: There is contradictory information on whether the rate of bone mineral density(BMD) loss is an independent risk factor for osteoporotic fractures and whether this should be included in fracture prediction systems. Objective: This study was undertaken to better define rate of BMD loss as a contributor to fracture risk in routine clinical practice. Design and Setting: We performed a retrospective cohort study using a database of all clinical BMD results for the province of Manitoba, Canada. Patients: We included 4498 untreated women age 40 yr and older at the time of a second BMD test performed between April 1996 and March 2009. Main Outcome Measures: A total of 146 women with major osteoporotic fracture outcomes after the second BMD test (mean observation, 2.7 yr) and relevant covariates were identified in population- based computerized health databases. Results: Annualized percentage change in total hip BMD was no greater in fracture compared to nonfracturewomen(-0. 4±1.7 vs.-0.5±1.4; P=0.166). After adjustment for final total hip BMD, other covariates, and medication use, rate of total hip BMD change did not predict major osteoporotic fractures (hazard ratio, 0.95 per SD decrease; 95% confidence interval, 0.81-1.10). Similar results were also seen in analyses based upon change in lumbar spine and femoral neck BMD. Conclusions: We found no evidence that BMD loss, as detected during routine clinical monitoring, was a significant independent risk factor for major osteoporotic fractures. Copyright © 2012 by The Endocrine Society. Source


Majumdar S.R.,University of Alberta | Ezekowitz J.A.,University of Alberta | Lix L.M.,University of Saskatchewan | Leslie W.D.,University of Manitoba
Journal of Clinical Endocrinology and Metabolism | Year: 2012

Objective: The aim of the study was to determine whether heart failure is associated with an increased risk of major osteoporotic fractures that is independent of bone mineral density (BMD). Methods:Weconducted a population-based cohort study in Manitoba, Canada, by linking a clinical registry of all adults 50 yr ofageandolderwhounderwentinitialBMDtestingfrom1998- 2009 with administrative databases. We collected osteoporosis risk factors, comorbidities, medications, and BMD results. Validated algorithms identified recent-onset heart failure before the BMD test and new fractures after. The main outcome was time to major osteoporotic fractures (i.e. clinical vertebrae, distal forearm, humerus, and hip), and multivariable proportional hazards models were used for analyses. Results: The cohort consisted of 45,509 adults; 1,841 (4%) had recent-onset heart failure. Subjects with heart failure were significantly (P<0.001) older (74 vs. 66 yr) and had more previous fractures (21 vs. 13%) and lower total hip BMD [T-score, -1.3 (SD 1.3) vs. -0.9 (SD 1.2)] than those without. There were 2703 incident fractures over the 5-yr observation. Overall,10%of heart failure subjects had incident major fractures compared with 5% of those without [unadjusted hazard ratio (HR), 2.45; 95% confidence interval (CI), 2.11-2.85]. Adjustment for osteoporosis risk factors, comorbidities, and medications attenuated but did not eliminate this association (HR, 1.33; 95% CI, 1.11-1.60), nor did further adjustment for total hip BMD (HR, 1.28; 95% CI, 1.06-1.53). Conclusions: Heart failure is associated with a 30% increase in major fractures that is independent of traditional risk factors and BMD, and it also identifies a high-risk population that may benefit from increased screening and treatment for osteoporosis. Copyright © 2012 by The Endocrine Society. Source


Fowler D.B.,University of Saskatchewan
Canadian Journal of Plant Science | Year: 2011

Accipiter is an intermediate height, high-yielding, winter wheat (Triticum aestivum L.) cultivar withgood stem and moderate leaf rust resistance that is registered for production in western Canada. It is a hard red winter wheat cultivar that is eligible for grades of the Canada Western General Purpose (CWGP) wheat class. The CWGP class was created in 2007 to encourage the development of cultivars to fill the high energy demands of the biofuel and livestock feed markets in western Canada. The grain yield of Accipiter was 114% of the Canada Western Red Winter Wheat class grain quality check cultivar, CDC Osprey, and 103% of the high-yielding check, CDC Falcon. High grain yield potential combined with good agronomic and disease packages make Accipiter a good fit for the CWGP class. Source


Gao C.,Chinese University of Hong Kong | Cai Y.,Chinese University of Hong Kong | Wang Y.,University of Saskatchewan | Kang B.-H.,University of Florida | And 3 more authors.
Trends in Plant Science | Year: 2014

Unless there are mechanisms to selectively retain membrane proteins in the endoplasmic reticulum (ER) or in the Golgi apparatus, they automatically proceed downstream to the plasma or vacuole membranes. Two types of coat protein complex I (COPI)-interacting motifs in the cytosolic tails of membrane proteins seem to facilitate membrane retention in the early secretory pathway of plants: a dilysine (KKXX) motif (which is typical of p24 proteins) for the ER and a KXE/D motif (which occurs in the Arabidopsis endomembrane protein EMP12) for the Golgi apparatus. The KXE/D motif is highly conserved in all eukaryotic EMPs and is additionally present in hundreds of other proteins of unknown subcellular localization and function. This novel signal may represent a new general mechanism for Golgi targeting and the retention of polytopic integral membrane proteins. © 2014 Elsevier Ltd. Source


Billinton R.,University of Saskatchewan | Karki B.,Teshmont Consultants L.P.
IEEE Transactions on Power Systems | Year: 2011

The paper presents well-being analysis of wind integrated electric power generating systems. An approach is presented for calculating well-being indices which gives much faster results than previously published methods. The link between the unit commitment risk criterion (UCRC) and system healthy state probability (HSPC) is illustrated using two different test systems. The method should prove useful in the decision making process of choosing an appropriate UCRC. The proposed approach extends the application of probabilistic techniques in operating reserve evaluation and determination. © 2006 IEEE. Source


Mohammadi R.,Urmia University | Azizi S.,Urmia University | Amini K.,University of Saskatchewan
Journal of Surgical Research | Year: 2013

Background/Aims: Employment of regenerative properties of stem cells at the service of nerve repair has been initiated during recent decades. Effects of transplantation of undifferentiated cultured omental adipose-derived stem cells (uADSCs) on peripheral nerve regeneration were studied using a rat sciatic nerve transection model. Methods: A 10-mm sciatic nerve defect was bridged using a silicone rubber chamber filled with uADSCs. In control group, the silicone conduit was filled with phosphate-buffered saline alone. The regenerated nerve fibers were studied 4, 8, and 12 wk after surgery. In sham-operated group, the sciatic nerve was only exposed and manipulated. Results: Functional study confirmed faster recovery of regenerated axons in uADSC-transplanted animals than in control group (P < 0.05). Gastrocnemius muscle mass in uADSC-transplanted animals is found to be significantly more than that in control group. Morphometric indices of the regenerated fibers showed that the number and diameter of the myelinated fibers were significantly higher in uADSC-transplanted animals than in control group. In immunohistochemistry, location of reactions to S-100 in uADSC-transplanted animals was clearly more positive than that in control group. Conclusion: uADSC transplantation could be considered as a readily accessible source of stromal cells that improve functional recovery of sciatic nerve. © 2013 Elsevier Inc. All rights reserved. Source


Sorghum seed (Sorghum bicolor L.) has unique degradation and fermentation behaviours compared with other cereal grains such as wheat, barley and corn. This may be related to its cell and cell-wall architecture. The advanced synchrotron radiation infrared microspectroscopy (SR-IMS) technique enables the study of cell or living cell biochemistry within cellular dimensions. The objective of this study was to use the SR-IMS imaging technique to microprobe molecular spatial distribution and cell architecture of the sorghum seed tissue comprehensively. High-density mapping was carried out using SR-IMS on beamline U2B at the National Synchrotron Light Source (Brookhaven National Laboratory, NY, USA). Molecular images were systematically recorded from the outside to the inside of the seed tissue under various chemical functional groups and their ratios [peaks at ∼1725 (carbonyl C=O ester), 1650 (amide I), 1657 (protein secondary structure α-helix), 1628 (protein secondary structure β-sheet), 1550 (amide II), 1515 (aromatic compounds of lignin), 1428, 1371, 1245 (cellulosic compounds in plant seed tissue), 1025 (non-structural CHO, starch granules), 1246 (cellulosic material), 1160 (CHO), 1150 (CHO), 1080 (CHO), 930 (CHO), 860 (CHO), 3350 (OH and NH stretching), 2960 (CH3 anti-symmetric), 2929 (CH2 anti-symmetric), 2877 (CH3 symmetric) and 2848 cm-1 (CH2 asymmetric)]. The relative protein secondary structure α-helix to β-sheet ratio image, protein amide I to starch granule ratio image, and anti-symmetric CH3 to CH2 ratio image were also investigated within the intact sorghum seed tissue. The results showed unique cell architecture, and the molecular spatial distribution and intensity in the sorghum seed tissue (which were analyzed through microprobe molecular imaging) were generated using SR-IMS. This imaging technique and methodology has high potential and could be used for scientists to develop specific cereal grain varieties with targeted food and feed quality, and can also be used to monitor the degree of grain maturity, grain damage, the fate of organic contaminants and the effect of chemical treatment on plant and grain seeds. © 2011 International Union of Crystallography. Source


Hobson K.A.,Environment Canada | Bond A.L.,Environment Canada | Bond A.L.,University of Saskatchewan
Marine Ecology Progress Series | Year: 2012

Stable isotope analysis of tissues of seabirds and their prey has proven to be an extremely useful tool in seabird dietary studies in general and in the potential use of seabirds as ecological indicators in particular. The measurement of stable carbon (δ 13C) and nitrogen (δ 15N) isotope values is important since they provide information on source of feeding and trophic position, respectively. However, the stable isotope approach provides information on spatial and trophic ecology of seabirds during a window of temporal integration that depends on the elemental turnover rate in the tissue being measured. Most researchers have relied on only 1 or 2 tissue types to study seabird diets and foraging ecology. Here, the potential for modeling trophic position and habitat use by seabirds over the annual cycle is demonstrated by using multiple tissues from the same individual. Isotopic measurements of bone collagen provide information integrated over the lifetime of the individual and those of feathers during the post-breeding molt period. Analysis of liver provides information integrated over the previous week and that of muscle integrated over a few months. We developed multi-tissue trophic models for thick-billed murre Uria lomvia, dovekie Alle alle, black guillemot Cepphus grylle, glaucous gull Larus hyperboreus, northern fulmar Fulmarus glacialis, black-legged kittiwake Rissa tridactyla, and ivory gull Pagophila eburnea using the Northwater Polynya in Northern Baffin Bay, 1998 to 1999. The careful application of stable isotope methods to a spectrum of tissue types represents a powerful means of extending our ability to investigate diet and potentially to use seabirds as ecological indicators. © Inter-Research 2012 · www.int-res.com. Source


Wyman D.,University of Sydney | Kerrich R.,University of Saskatchewan
Canadian Journal of Earth Sciences | Year: 2010

The Abitibi and Wawa subprovinces of the southern Superior Province differ in terms of the extent of preexisting 2750 Ma sialic crust and relationships between mantle plume type (tholeiitic basalt - komatiite) and arc type (tholeiite to calc-alkaline basalt - andesite - dacite - rhyolite) volcanic successions but evolved in close proximity to each other. Isotopic data, evidence from the Kapuskasing uplift, continuation of major structures associated with large gold deposits from the Abitibi into the Wawa subprovince and the related occurrence of diamonds in lamprophyric rocks in both subprovinces point to a common evolution prior to and during orogeny. Differences preserved in supracrustal sequences of the two subprovinces suggest that the main petrogenetic controls on orogenic gold deposits and lamprophyre-hosted diamond deposits lay in the lower crust and upper mantle. Similar processes must also have been active where gold and diamonds are associated on other Archean cratons, such as the Slave and possibly the Kaapvaal craton. Based on evidence preserved in the Abitibi-Wawa orogen, rapid crustal growth at ~2.7 Ga was linked to the interplay between plate tectonics and mantle plumes. Key indicators in the model developed for the Abitibi-Wawa arc are the co-existence of plumerelated rock types, modern-style adakites, major gold deposits, and lamprophyre-hosted diamond occurrences, at least in cases where shoshonitic host magmas can ascend rapidly through the crust. All of these indicators are now identified on the Kaapvaal craton by 3.1 Ga and many recur together in Paleoproterzoic and younger terranes, suggesting a common mechanism for rapid crustal growth through much of Earth's history. The variety of granitoid types found within the Abitibi-Wawa orogen demonstrates that local tectonic factors, rather than a hotter average upper mantle, were important in controlling the type of magmas formed. Based on the geodynamic history of the subprovince, mantle plume interaction with an existing volcanic arc and the subduction of oceanic plateau crust played an important role in the formation of magmas similar to Cenozoic adakites. Flat subduction beneath a mantle wedge was probably responsible for the generation of the adakites and also promoted diamond stability at shallow depths while enhancing the reservoirs for subsequent orogenic gold deposits. The history of magmatism and mineralization in the Abitibi and Wawa subprovinces precludes an early or gradual development of a cratonic keel, which instead must have coupled with crust during the latest stages of orogeny. Source


Agnihotri N.,University of Saskatchewan
Journal of Photochemistry and Photobiology C: Photochemistry Reviews | Year: 2013

Photoinduced charge transfer (CT) is a fundamental process that determines the overall energy conversion efficiency of organic solar photovoltaic cells (OPVs). This review focuses on the advantages and pitfalls of theoretical/computational methods available to describe CT excitations in donor-acceptor (D-A) complexes. Studies of porphyrin-fullerene constructs as model D-A systems will be used to illustrate progress in this area. © 2013 Elsevier B.V. Source


Morozov I.B.,University of Saskatchewan
Geophysics | Year: 2010

Several extensions of the concept of acoustic impedance (AI) to oblique incidence exist and are known as elastic impedances (EI). These quantities are constructed by heuristic integrations of reflectivity series but still involve approximations and do not represent a unique medium property. Nevertheless, for unambiguous interpretation, it is desirable to have an EI that would (1) be a mechanical property of the medium and (2) yield exact reflection coefficients at all angles of incidence. Here, such a definition is given for P- and/or SV-wave propagation in an arbitrary isotropic medium. The exact elastic P/SV impedance is a matrix quantity and represents the differential operator relating the stress and strain boundary conditions. With the use of the matrix form of the reflectivity problem, no approximations are required for accurate modeling of reflection (P/P and SV/SV) and mode-conversion (P/SV and SV/P) coefficients at all angles and for any contrasts in elastic properties. The matrix EI can be computed from real well logs and inverted from ray-parameter-dependent seismic reflectivity. Known limiting cases of P- and S-wave acoustic impedances are accurately reproduced and the approach also allows the extension of the concept of impedance to an attenuative medium. The matrix impedance readily lends itself to inversion with uncertainties typical of the standard acoustic-impedance inversion problem. © 2010 Society of Exploration Geophysicists. Source


Holmden C.,University of Saskatchewan | Belanger N.,University of Quebec at Montreal
Geochimica et Cosmochimica Acta | Year: 2010

Reports of large Ca isotope fractionations between trees and soils prompted this study of a Boreal forest ecosystem near La Ronge, Saskatchewan, to improve understanding of this phenomenon. The results on five tree species (black spruce, trembling aspen, white spruce, jack pine, balsam poplar) confirm that nutrient Ca uptake by plants favors the light isotopes, thus driving residual Ca in plant available soil pools towards enrichment in the heavy isotopes. Substantial within-tree fraction occurs in tissues formed along the transpiration stream, with low δ44Ca values in fine roots (2 mm), intermediate values in stemwood, and high values in foliage. Separation factors between different plant tissues are similar between species, but the initial fractionation step in the tips of the fine roots is species specific, and/or sensitive to the local soil environment. Soil water δ44Ca values appear to increase with depth to at least 35 cm below the top of the forest floor, which is close to the deepest level of fine roots. The heavy plant fractionated signature of Ca in the finely rooted upper soils filters downward where it is retained on ion exchange sites, leached into groundwater, and discharged into surface waters. The relationship between Ca uptake by tree fine roots and the pattern of δ44Ca enrichment with soil depth was modeled for two Ca pools: the forest floor (litter) and the underlying (upper B) mineral soil. Six study plots were investigated along two hillside toposequences trending upwards from a first order stream. We used allometric equations describing the Ca distribution in boreal tree species to calculate weighted average δ44Ca values for the stands in each plot and estimate Ca uptake rates. The δ44Ca value of precipitation was measured, and soil weathering signatures deduced, by acid leaching of lower B mineral soils. Steady state equations were used to derive a set of model Ca fluxes and fractionation factors for each plot. The model reproduces the increase in δ44Ca with depth found in forest floor and upper B soil waters. Transient model runs show that the forest Ca cycle is sensitive to changes in plant Ca uptake rate, such as would occur during ontogeny or disturbance. Accordingly, secular records of δ44Ca in tree ring cellulose have the potential to monitor changes in the forest Ca cycle through time, thus providing a new tool for evaluating natural and anthropogenic impacts on forest health. Another model run shows that by changing the size of the isotope fractionation factor and adjusting for differences in forest productivity, that the range in Ca isotope fractionation in forested ecosystems reported in the literature, thus far, is reproduced. As a quantitative tool, the Ca cycling model produces a reasonable set of relative Ca fluxes for the La Ronge site, consistent with Environment Canada's measurements for wet deposition in the region and simulated Ca release from soil mineral weathering using the PROFILE model. But the sensitivity of the model is limited by the small range of fractionation observed in this boreal shield setting of ∼1‰, which limits accuracy. If the model were applied to a site with a greater range in δ44Ca values among the principal Ca fluxes, it is capable of producing robust and reliable estimations of Ca fluxes that are otherwise difficult to measure in forested ecosystems. © 2009. Source


Wu Y.,University of Saskatchewan | Brosh Jr. R.M.,U.S. National Institute on Aging
Nucleic Acids Research | Year: 2012

Conserved Iron-Sulfur (Fe-S) clusters are found in a growing family of metalloproteins that are implicated in prokaryotic and eukaryotic DNA replication and repair. Among these are DNA helicase and helicase-nuclease enzymes that preserve chromosomal stability and are genetically linked to diseases characterized by DNA repair defects and/or a poor response to replication stress. Insight to the structural and functional importance of the conserved Fe-S domain in DNA helicases has been gleaned from structural studies of the purified proteins and characterization of Fe-S cluster site-directed mutants. In this review, we will provide a current perspective of what is known about the Fe-S cluster helicases, with an emphasis on how the conserved redox active domain may facilitate mechanistic aspects of helicase function. We will discuss testable models for how the conserved Fe-S cluster might operate in helicase and helicase-nuclease enzymes to conduct their specialized functions that help to preserve the integrity of the genome. © 2011 The Author(s). Source


Fang J.,University of Saskatchewan
Drug Metabolism Reviews | Year: 2014

Anthocyanins are a subgroup of flavonoids responsible for the blue, purple, and red color of many fruits, flowers, and leaves. Consumption of foods rich in anthocyanins has been associated with a reduced risk of cardiovascular disease and cancer. The fate of anthocyanins after oral administration follows a unique pattern rather different from those of other flavonoids. Anthocyanins could be absorbed from the stomach as well as intestines. Active transporters may play a role in the absorption of anthocyanins from the stomach as well as in their transfer within the kidney or liver. Anthocyanins such as cyanidin-3-glucoside and pelargonidin-3-glucoside could be absorbed in their intact form into the gastrointestinal wall; undergo extensive first-pass metabolism; and enter the systemic circulation as metabolites. Phenolic acid metabolites were found in the blood stream in much higher concentrations than their parent compounds. These metabolites could be responsible for the health benefits associated with anthocyanins. Some anthocyanins can reach the large intestine in significant amounts and undergo decomposition catalyzed by microbiota. In turn, these decomposition products may contribute to the health effects associated with anthocyanins in the large intestine. This review comprehensively summarizes the existing knowledge about absorption, distribution, metabolism, and elimination of anthocyanins as well as their decomposition within the gastrointestinal lumen. © 2014 Informa Healthcare USA, Inc. Source


Ellis J.,University of Saskatchewan
Veterinary Pathology | Year: 2014

Porcine circoviruses (PCVs) belong to the genus Circovirus and the family Circoviridae, and they are the smallest known viruses that replicate autonomously in mammalian cells. They are nonenveloped, and they have characteristic single-stranded, negative-sense, circular DNA. Two types of divergent PCVs are recognized: PCV1 and PCV2. About 20 years ago, PCV2 began to emerge as a major pathogen of swine around the world, leading to burgeoning knowledge about the virus and porcine circovirus-associated diseases. However, much of the history of its discovery, including the controversy related to its importance, is not recorded. This review examines current issues related to the biology of PCV2 in the context of the original studies related to determining its causal association with disease and to the evolving understanding of the complex pathogenesis of PCV2 infections. © The Author(s) 2014. Source


Cheviakov A.F.,University of Saskatchewan
Journal of Engineering Mathematics | Year: 2010

The direct method for the construction of local conservation laws of partial differential equations (PDE) is a systematic method applicable to a wide class of PDE systems (S. Anco and G. Bluman, Eur J Appl Math 13:567-585, 2002). According to the direct method one seeks multipliers, such that the linear combination of PDEs of a given system with these multipliers yields a divergence expression. Once local-conservation-law multipliers have been found, one needs to reconstruct the fluxes of the conservation law. In this review paper, common methods of flux computation are discussed, compared, and illustrated by examples. An implementation of these methods in symbolic software is also presented. © Springer Science+Business Media B.V. 2009. Source


Ngo D.T.,McGill University | Tellambura C.,University of Alberta | Nguyen H.H.,University of Saskatchewan
IEEE Transactions on Vehicular Technology | Year: 2010

This paper considers the primary user activity or the subchannel availability in optimally distributing the available resources for an orthogonal frequency-division multiple-access (OFDMA) cognitive radio multicast network. For this purpose, a risk-return model is presented, and a general rate-loss function, which gives a reduction in the attainable throughput whenever primary users reoccupy the temporarily accessible subchannels, is introduced. Taking the maximization of the expected sum rate of secondary multicast groups as the design objective, an efficient joint subcarrier and power-allocation scheme is proposed. Specifically, the design problem is solved via a dual optimization method under constraints on the tolerable interference thresholds at individual primary user's frequency bands. It is shown that as the number of subcarriers gets large (which is often the case in practice), the dual-domain solution becomes globally optimum with regard to the primal problem. More attractively, the "practically optimal" performance of this approach is achieved with a substantially lower complexity, which is only linear in the total number of subcarriers as opposed to exponential complexity typically required by a direct search method. Our proposed design is valid for unicast and multicast transmissions and is applicable for a wide range of rate-loss functions, among which, the linear function is a special case. The superiority of the dual scheme is thoroughly verified by numerical examples. © 2006 IEEE. Source


Awada L.,University of Saskatchewan | Yiannaka A.,University of Nebraska - Lincoln
Food Policy | Year: 2012

The study develops a general analytical framework of heterogeneous consumer preferences to examine the effects of country of origin labeling (COOL) regulation on consumer purchasing decisions and welfare. We show that while differences in consumer perceptions about COOL information, namely, whether it is viewed as an attribute that differentiates products vertically or horizontally, do not alter the nature of the market and consumer welfare effects of mandatory COOL, the relative strength of consumer preferences for COOL are shown to be important in determining the magnitude of these effects. In addition, our results show that the benchmark used (a no COOL versus a voluntary COOL regime) is critical in evaluating the effects of the policy. We show that, under both horizontal and vertical product differentiation, a change from a no COOL to a mandatory COOL regime decreases (increases) the welfare of consumers with weak (strong) preference for COOL while a change from a voluntary to a mandatory COOL regime leads to an unambiguous loss in consumer welfare. © 2011 Elsevier Ltd. Source


Classen H.L.,University of Saskatchewan
Animal Feed Science and Technology | Year: 2016

Energy homeostasis is of fundamental importance to animal well-being as well as in the feeding of species like chickens. Optimizing the balance between energy intake and expenditures is required for efficient, highly productive flocks, and understanding its relationship to production characteristics including energy and feed intake is fundamental to the formulation of chicken diets and levels of other dietary nutrients. A historical perspective on this relationship is that chickens alter feed intake to maintain energy intake when diets contain variable dietary energy. In turn levels of other nutrients, and in particular amino acids, should be adjusted in accordance. However, control of feed intake is complex and even if this perspective were correct, multiple factors can compromise the appropriate adjustment in feed intake. The validity of broilers altering feed intake in response to dietary energy has been questioned for some time and more recent evidence suggests that modern strains of laying hens also are unable to accurately or reliably alter feed intake in response to dietary energy levels. Based on the premise that chickens do not appropriately respond to dietary energy, diets must therefore be formulated to ensure adequate dietary energy to meet the bird's requirements for maintenance and production, and thereby maximize the protein accretion potential of the diet. © 2016 Elsevier B.V. Source


Ferguson G.,University of Saskatchewan
Environmental Research Letters | Year: 2013

Anthropogenic climate change and energy security concerns have created a demand for new ways of meeting society's demand for energy. The Earth's crust is being targeted in a variety of energy developments to either extract energy or facilitate the use of other energy resources by sequestering emitted carbon dioxide. Unconventional fossil fuel developments are already being pursued in great numbers, and large scale carbon capture and sequestration and geothermal energy projects have been proposed. In many cases, these developments compete for the same subsurface environments and they are not necessarily compatible with each other. Policy to regulate the interplay between these developments is poorly developed. Here, the subsurface footprints necessary to produce a unit of energy from different developments are estimated to assist with subsurface planning. The compatibility and order of development is also examined to aid policy development. Estimated subsurface energy footprints indicate that carbon capture and sequestration and geothermal energy developments are better choices than unconventional gas to supply clean energy. © 2013 IOP Publishing Ltd. Source


Candow D.G.,University of Regina | Chilibeck P.D.,University of Saskatchewan | Forbes S.C.,University of Calgary
Endocrine | Year: 2014

Sarcopenia refers to the progressive loss of muscle mass and muscle function and is a contributing factor for cachexia, bone loss, and frailty. Resistance training produces several physiological adaptations which improve aging musculoskeletal health, such as increased muscle and bone mass and strength. The combination of creatine supplementation and resistance training may further lead to greater physiological benefits. We performed meta-analyses which indicate creatine supplementation combined with resistance training has a positive effect on aging muscle mass and upper body strength compared to resistance training alone. Creatine also shows promise for improving bone mineral density and indices of bone biology. The combination of creatine supplementation and resistance training could be an effective intervention to improve aging musculoskeletal health. © 2013 Springer Science+Business Media. Source


Sumner D.,University of Saskatchewan
Journal of Fluids and Structures | Year: 2010

Pairs of circular cylinders immersed in a steady cross-flow are encountered in many engineering applications. The cylinders may be arranged in tandem, side-by-side, or staggered configurations. Wake and proximity interference effects, which are determined primarily by the longitudinal and transverse spacing between the cylinders, and also by the Reynolds number, have a strong influence on the flow patterns, aerodynamic forces, vortex shedding, and other parameters. This paper reviews the current understanding of the flow around two "infinite" circular cylinders of equal diameter immersed in a steady cross-flow, with a focus on the near-wake flow patterns, Reynolds number effects, intermediate wake structure and behaviour, and the general trends in the measurements of the aerodynamic force coefficients and Strouhal numbers. A primary focus is on the key experimental and numerical studies that have appeared since the last major review of this subject more than 20 years ago. © 2010 Elsevier Ltd. Source


Juurlink B.H.J.,University of Saskatchewan
Current Neurovascular Research | Year: 2015

The dominant hypothesis in multiple sclerosis is that it is an autoimmune disease; however, there is considerable evidence that the immune attack on myelin may be secondary to a cytodegenerative event. Furthermore, the immune modulating therapies longest in clinical use, although modulating the frequency and severity of exacerbation, do not affect long-term progression towards disability. Clearly alternative perspectives on the etiology of multiple sclerosis are warranted. In this paper I outline the commonalities between idiopathic normal pressure hydrocephalus and multiple sclerosis. These include decreased intracranial compliance as evidenced by increased cerebrospinal fluid volume and velocity of cerebrospinal fluid flow through the cerebral aqueduct; increased ventricular volume; periventricular demyelination lesions; increase in size of Virchow-Robin spaces; presence of Hakim's triad comprised of locomotory disabilities, cognitive problems and bladder control problems. Furthermore, multiple sclerosis is associated with decreased arterial compliance. These are all suggestive that there is a pulse wave encephalopathy component to multiple sclerosis. There are enough resemblances between normal pressure hydrocephalus and multiple sclerosis to warrant further investigation. Whether decreases in intracranial compliance is a consequence of multiple sclerosis or is a causal factor is unknown. Effective therapies can only be developed when the etiology of the disease is understood. Source


Despite the accumulating evidence supporting the health effects of anthocyanins, their plasma concentrations were found to be very low. However, 30 and 56% of cyanidin 3-glucoside (Cy-3-glc) and pelargonidin 3-glucoside (Pg-3-glc) were found as protocatechuic acid (PCA) and 4-hydroxybenzoic acid, respectively, in plasma following oral administration in humans. Second, 12.4% of 13C was recovered from urine and breath following oral ingestion of [13C]-Cy-3-glc in humans. The actual percentage of [ 13C]-Cy-3-glc absorbed across the gastrointestinal wall could be higher because of the involvement of enterohepatic recycling in the disposition of anthocyanins. In animal studies, high total urinary recoveries were found following oral ingestion of 14C-labeled anthocyanins. Third, anthocyanins seem to be efficiently absorbed following in situ gastric and intestinal perfusions in rats. Therefore, some anthocyanins could be efficiently absorbed from the gastrointestinal lumen, undergo extensive first-pass metabolism, and enter the systemic circulation as metabolites. © 2014 American Chemical Society. Source


Fleming I.R.,University of Saskatchewan
Waste Management | Year: 2011

Management and prediction of the movement and distribution of fluids in large landfills is important for various reasons. Bioreactor landfill technology shows promise, but in arid or semi-arid regions, the natural content of landfilled waste may be low, thus requiring addition of significant volumes of water. In more humid locations, landfills can become saturated, flooding gas collection systems and causing sideslope leachate seeps or other undesirable occurrences.This paper compares results from two different approaches to monitoring water in waste. At the Brock West Landfill in eastern Canada, positive pore pressures were measured at various depths in saturated waste. The downward seepage flux through the waste is known, thus the vertical saturated hydraulic conductivity of the waste at this landfill was determined to be 3×10 -7cm/s.By comparison, the Spadina Landfill in western Canada is predominantly unsaturated. The infiltration of moisture into the waste was measured using moisture sensors installed in boreholes which determined arrival time for moisture fronts resulting from major precipitation events as well as longer-term change in moisture content resulting from unsaturated drainage during winter when frozen ground prevented infiltration. The unsaturated hydraulic conductivity calculated from these data ranged from approximately 10 -6cm/s for the slow winter drainage in the absence of significant recharge to 10 -2cm/s or higher for shallow waste subject to high infiltration through apparent preferential pathways.These two very different approaches to field-scale measurements of vertical hydraulic conductivity provide insight into the nature of fluid movement in saturated and unsaturated waste masses. It is suggested that the principles of unsaturated seepage apply reasonably well for landfilled waste and that the hydraulic behavior of waste is profoundly influenced by the nature and size of voids and by the degree of saturation prevailing in the landfill. © 2011 Elsevier Ltd. Source


Johnston M.,Saskatchewan Research Council | Hesseln H.,University of Saskatchewan
Forest Policy and Economics | Year: 2012

Canada's forests will be affected by climate change to a greater degree than many other regions. The ability of the Canadian forest sector to successfully adapt to climate change, i.e. its adaptive capacity, was assessed through a series of group discussions and interviews with a variety of forestry stakeholders across Canada. The assessment was oriented to the following determinants of adaptive capacity: 1) The range of available technological options for adaptation that would be considered in response to a perceived climate-related stress; 2) The availability of resources; 3) The structure and functionality of critical institutions to understand the allocation of decision-making authority, institutional flexibility, and the decision criteria that would be employed; 4) Human and social capital, including the distribution of educational achievement, differential access to personal security and robust property rights; 5) The system's (and individuals') access to risk-spreading processes (both formal and informal); 6) Decision-makers' ability to manage information, the processes by which these decision-makers determine which information is credible, and the credibility of the decision-makers themselves. Forest managers were generally optimistic about their ability to identify and implement adaptation options at the forest management unit level. However, institutional barriers were seen to be a major impediment; managers identified tenure reform and a more flexible regulatory environment as essential for the innovation that will be required by climate change. Other factors limiting adaptive capacity include lack of financial resources and low levels of investment in the forest sector, lack of specialized science capacity in climate change impacts and the long-term nature of planning required by long-lived forest species. Several non-governmental institutions may support increased adaptive capacity including forest certification systems, Criteria and Indicators of Sustainable Forest Management, Canada's model forest program and others. However, these institutions will need to be modified in order to support forest managers in planning for climate change. © 2012 Elsevier B.V. Source


Thoma B.,University of Saskatchewan
International Review of Psychiatry | Year: 2015

Social media is difficult to explain to a physician who has never used it. The medical literature on its pitfalls and abuses has overshadowed its positive applications and made many physicians wary of it. While I was initially reluctant to develop my own presence on social media, since embracing it as a tool for teaching and learning I have developed a different perspective. I see it as a tool that can be used positively or negatively. Much like a megaphone, it can amplify our voice so that the impact of our work can extend beyond the borders of our institutions and countries. Aided by the guidance and support of mentors who used social media before and alongside me, it has helped me to become a more competent, professional, engaged, and impactful physician. Within this article I will share my story to illustrate the many ways that social media can be used to enhance the profession of medicine. © 2015 Institute of Psychiatry. Source


Hiebert L.M.,University of Saskatchewan | Han J.,Cleveland Clinic | Mandal A.K.,Mandal Diabetes Research Foundation
Antioxidants and Redox Signaling | Year: 2014

Significance: Diabetes is a widespread disease with many clinical pathologies. Despite numerous pharmaceutical strategies for treatment, the incidence of diabetes continues to increase. Hyperglycemia, observed in diabetes, causes endothelial injury resulting in microvascular and macrovascular complications such as nephropathy, retinopathy, neuropathy, and increased atherosclerosis. Recent Advances: Proteoglycans are chemically diverse macromolecules consisting of a protein core with glycosaminoglycans (GAGs) attached. Heparan sulfate proteoglycans are important compounds found on the endothelial cell membrane and in the extracellular matrix, which play an important role in growth regulation and serve as a reservoir for cytokines and other bioactive molecules. Endothelial cells are altered in hyperglycemia by a reduction in heparan sulfate and upregulation and secretion of heparanase, an enzyme that degrades heparan sulfate GAGs on proteoglycans. Reactive oxygen species, increased in diabetes, also destroy GAGs. Critical Issues: Preservation of heparan sulfate proteoglycans on endothelial cells may be a strategy to prevent angiopathy associated with diabetes. The use of GAGs and GAG-like compounds may increase endothelial heparan sulfate and prevent an increase in the heparanase enzyme. Future Directions: Elucidating the mechanisms of GAG depletion and its significance in endothelial health may help to further understand, prevent, and treat cardiovascular complications associated with diabetes. Further studies examining the role of GAGs and GAG-like compounds in maintaining endothelial health, including their effect on heparanase, will determine the feasibility of these compounds in diabetes treatment. Preservation of heparan sulfate by decreasing heparanase may have important implications not only in diabetes, but also in cardiovascular disease and tumor biology. © Copyright 2014, Mary Ann Liebert, Inc. 2014. Source


Ndisang J.F.,University of Saskatchewan
Frontiers in Bioscience - Landmark | Year: 2014

Peroxisome-proliferator-activated-receptors (PPARs) are transcription factors belonging to the superfamily of nuclear receptors. The isoforms of PPAR include PPAR alpha, PPAR gamma and PPAR delta (also known as PPAR beta). Generally, PPARs potentiate insulin sensitivity, improve glucose/lipid metabolism, suppress inflammation/oxidative stress, attenuate excessive immune responses, regulate cell-growth and differentiation. Interestingly, agonists of PPAR gamma and PPAR alpha have been shown to upregulate the heme-oxygenase (HO)-system. Conversely, the HO-system also enhances PPAR alpha, and potentiates the expression and activity of PPAR g . Moreover, the HO-system and related products including bilirubin, biliverdin, carbon monoxide and ferritin have been shown to increase insulin sensitivity, improve glucose/lipid metabolism, suppress inflammation/oxidative stress, abate immune response, and modulate cell-growth/differentiation. Therefore, an intimate, reciprocal, stimulatory and synergistic relationship between PPAR-signaling and the HO-system can be envisaged in the regulation of physiological functions. Thus, both the HO-system and PPARs-signaling participate in fine-tuning similar physiological functions, so novel pharmacological agents capable of optimizing this interaction should be sought. The coordinated regulation of PPAR-signaling and the HO-system may constitute the basis for future drug design. Source


Sowa A.,University of Saskatchewan
Waves in Random and Complex Media | Year: 2012

We discuss the nonlinear eigenvalue problem and fully resolve it in two different settings. Namely, we first pose the problem in the space of the classical Dirichlet series. We find a complete set of eigenfunctions in this space, and their corresponding eigenvalues. Secondly, we pose the problem in the space of functions on the unit circle which admit a holomorphic extension to an open neighborhood of the unit disk. We obtain a complete set of solutions in this case also. In both cases the eigenfunctions are scale-similar. Both types of solutions are obtained via a reduction of the underlying problem to a set of discrete conditions on series coefficients. In fact, the discrete problem is identical for both settings. We discuss the intriguing correspondence between the two sets of solutions in detail. The methods developed here appear applicable to a broader range of differential eigenvalue problems. Furthermore, the results are applicable to circuit analysis as well as signal analysis, particularly in the context of nanocircuits with memristance. © 2012 Copyright Taylor and Francis Group, LLC. Source


Meesapyodsuk D.,National Research Council Canada | Qiu X.,National Research Council Canada | Qiu X.,University of Saskatchewan
ACS Chemical Biology | Year: 2014

In contrast to soluble acyl-ACP desaturases from plants, little is known about the structure-guiding principle underlying substrate specificity and regioselectivity of membrane-bound acyl-CoA desaturases from animals, mainly due to lack of the three-dimensional structure information. Here we report identification of two homologous membrane-bound acyl-CoA Δ9 desaturases (ChDes9-1 and ChDes9-2) from the marine copepod Calanus hyperboreus that accumulates more than 90% of total storage lipids in the form of wax esters. ChDes9-2 is a common Δ9 desaturase with substrate specificity to long chain fatty acid 18:0, while ChDes9-1 is a new type of Δ9 desaturase introducing a Δ9 double bond into a wide range of very long chain fatty acids ranging from 20:0 to 26:0. Reciprocal domain swapping and site-directed mutagenesis guided by the membrane topology revealed that presence or absence of an amphipathic and bulky residue, tyrosine, in the middle of the second transmembrane domain was important in determining the substrate specificity of the two desaturases. To examine the mechanistic structure for the substrate specificity, tyrosine-scanning mutagenesis was employed to systematically substitute the residues in the transmembrane domain of the very long chain desaturase. The results showed that the transmembrane domain formed an α-helix structure probably involved in formation of the substrate-binding pocket and the corresponding residue of the tyrosine likely resided at the critical position within the pocket mediating the interaction with the substrates, thereby specifying the chain length of the substrates. © 2014 American Chemical Society. Source


Grassmann W.K.,University of Saskatchewan
Simulation | Year: 2014

In this paper, we discuss the factors affecting the initialization bias in discrete event simulation. Specifically, we assume that the time average is used to find the equilibrium expectation of a certain variable R, say the number in a queueing network, and we would like to minimize the mean squared error (MSE) between the time average of R and its equilibrium expectation. To do this, a warm-up period is often used during which no data is collected, and we want to find the length of this period such that the MSE is minimal. We show that if starting in what Tocher calls a "typical condition", warm-ups tend to be redundant. This result is strengthened by theoretical arguments and numerical experiments. If starting in a typical state is inconvenient, warm-up periods should be used, and methods to find optimal warm-up periods are discussed. The numerical methods used for our experiments do not rely on Monte Carlo simulation. Instead, we determine the MSE of the time average by the randomization method and other deterministic methods. © 2013 The Society for Modeling and Simulation International. Source


Bai X.,CAS Kunming Institute of Botany | Todd C.D.,University of Saskatchewan | Desikan R.,Imperial College London | Yang Y.,CAS Kunming Institute of Botany | Hu X.,CAS Kunming Institute of Botany
Plant Physiology | Year: 2012

N-Acyl-homoserine-lactones (AHLs) are bacterial quorum-sensing signaling molecules that regulate population density. Recent evidence demonstrates their roles in plant defense responses and root development. Hydrogen peroxide (H 2O 2), nitric oxide (NO), and cyclic GMP (cGMP) are essential messengers that participate in various plant physiological processes, but how these messengers modulate the plant response to N-acyl-homoserine-lactone signals remains poorly understood. Here, we show that the N-3-oxo-decanoyl-homoserine-lactone (3-O-C10-HL), in contrast to its analog with an unsubstituted branch chain at the C3 position, efficiently stimulated the formation of adventitious roots and the expression of auxin-response genes in explants of mung bean (Vigna radiata) seedlings. This response was mimicked by the exogenous application of auxin, H 2O 2, NO, or cGMP homologs but suppressed by treatment with scavengers or inhibitors of H 2O 2, NO, or cGMP metabolism. The 3-O-C10-HL treatment enhanced auxin basipetal transport; this effect could be reversed by treatment with H 2O 2 or NO scavengers but not by inhibitors of cGMP synthesis. Inhibiting 3-O-C10-HL-induced H 2O 2 or NO accumulation impaired auxin- or 3-O-C10-HL-induced cGMP synthesis; however, blocking cGMP synthesis did not affect auxin- or 3-O-C10-HLinduced H 2O 2 or NO generation. Additionally, cGMP partially rescued the inhibitory effect of H 2O 2 or NO scavengers on 3-OC10- HL-induced adventitious root development and auxin-response gene expression. These results suggest that 3-O-C10-HL, unlike its analog with an unmodified branch chain at the C3 position, can accelerate auxin-dependent adventitious root formation, possibly via H 2O 2- and NO-dependent cGMP signaling in mung bean seedlings. © 2011 American Society of Plant Biologists. Source


Mondal T.,Indian Institute of Technology Delhi | Pant K.K.,Indian Institute of Technology Delhi | Dalai A.K.,University of Saskatchewan
International Journal of Hydrogen Energy | Year: 2015

Catalytic steam reforming of bio-ethanol in presence of oxygen for hydrogen production was studied over Ni/CeO2-ZrO2 and Rh-Ni/CeO2-ZrO2 catalysts. The catalysts were prepared by an impregnation-co-precipitation method and characterized by various characterization techniques. Characterization results revealed that addition of ZrO2 improves the oxygen storage capacity of CeO2 which improves catalytic activity. The effects of temperature, ethanol/water/oxygen molar ratio, and space time on ethanol conversion and product selectivities were investigated using a tubular fixed bed reactor at atmospheric pressure. Complete ethanol conversion was achieved at 600 °C with a maximum hydrogen yield of 4.6 mol/mol on the 1%Rh-30%Ni/CeO2-ZrO2 catalyst. Ethanol conversion and H2 selectivity were increased with increasing contact time, while CO and CH4 selectivity decreased. Investigation revealed Rh promoted catalyst exhibited better catalytic activity than 30%Ni/CeO2-ZrO2 catalyst for oxidative steam reforming of ethanol, indicating that addition of Rh improved the catalytic activity significantly by promoting water gas shift reaction. © 2014 Hydrogen Energy Publications, LLC. Source


Hendry M.J.,University of Saskatchewan | Harrington G.A.,Innovative Solutions
Water Resources Research | Year: 2014

Comparing high-resolution depth profiles of different naturally occurring environmental tracers in aquitards should yield consistent and perhaps complementary information about solute transport mechanisms and the timing of major hydrogeological and climatological events. This study evaluated whether deep, continuous profiles of aquitard pore water chloride concentration could provide further insight into the paleohydrology of the Williston Basin, Canada, than possible using high-resolution depth profiles of stable H/O isotopes of water (δ18O, δ2H). Pore water samples were obtained from extracts of cores taken over 392 m of the thick Cretaceous shale aquitard. Water samples were also collected from wells installed in the underlying regional sandy aquifer (Mannville Group; 93 m thick) and from seepage inflows into potash mine shafts (to 825 m below ground). Numerical modeling of the 1-D vertical Cl- profile supported diffusion dominated solute transport in the shales. The modeling also showed a similar time frame for development of the Cl- profile prior to activation of the aquifer as determined from the δ18O profile (20-25 Ma); however, it provided a significantly longer and potentially better-constrained time frame for evolution of the profile during the activation phase of the aquifer (0.5-1 Ma). The dominant paleoevent reflected in present-day profiles of both tracers is the introduction of glaciogenic meteoric water to the Mannville aquifer underlying the shale during the Pleistocene. The source area of this water remains to be determined. © 2014. American Geophysical Union. Source


Engler-Stringer R.,University of Saskatchewan
Canadian Journal of Dietetic Practice and Research | Year: 2010

Over the past century, a major shift in North American food practices has been taking place. However, the literature on this topic is lacking in several areas. Some available research on food and cooking practices in the current context is presented, with a focus on how these are affecting health and how they might be contributing to health inequalities within the population. First, cooking and cooking skills are examined, along with the ambiguities related to terms associated with cooking in the research literature. Food choice, cooking, and health are described, particularly in relation to economic factors that may lead to health inequalities within the population. The importance of developing an understanding of factors within the wider food system as part of food choice and cooking skills is presented, and gaps in the research literature are examined and areas for future research are presented. Cooking practices are not well studied but are important to an understanding of human nutritional health as it relates to cultural, environmental, and economic factors. Source


Ferrari M.C.O.,WCVM | McCormick M.I.,James Cook University | Meekan M.G.,Australian Institute of Marine Science | Chivers D.P.,University of Saskatchewan
Proceedings of the Royal Society B: Biological Sciences | Year: 2015

Neophobia—the generalized fear response to novel stimuli—provides the first potential strategy that predator-naive prey may use to survive initial predator encounters. This phenotype appears to be highly plastic and present in individuals experiencing high-risk environments, but rarer in those experiencing low-risk environments. Despite the appeal of this strategy as a ‘solution’ for prey naivety, we lack evidence that this strategy provides any fitness benefit to prey. Here, we compare the relative effect of environmental risk (high versus low) and predator-recognition training (predator-naive versus predator- experienced individuals) on the survival of juvenile fish in the wild. We found that juveniles raised in high-risk conditions survived better than those raised in low-risk conditions, providing the first empirical evidence that environmental risk, in the absence of any predator-specific information, affects theway naive prey survive in a novel environment. Both risk level and experience affected survival; however, the two factors did not interact, indicating that the information provided by both factors did not interfere or enhance each other. From a mechanistic viewpoint, this indicates that the combination of the two factors may increase the intensity, and hence efficacy, of prey evasion strategies, or that both factors provide qualitatively separate benefits that would result in an additive survival success. © 2014 The Author(s) Published by the Royal Society. All rights reserved. Source


Reddy S.N.,Lassonde | Nanda S.,Lassonde | Dalai A.K.,University of Saskatchewan | Kozinski J.A.,Lassonde
International Journal of Hydrogen Energy | Year: 2014

Hydrogen from waste biomass is considered to be a clean gaseous fuel and efficient for heat and power generation due to its high energy content. Supercritical water gasification is found promising in hydrogen production by avoiding biomass drying and allowing maximum conversion. Waste biomass contains cellulose, hemicellulose and lignin; hence it is essential to understand their degradation mechanisms to engineer hydrogen production in high-pressure systems. Process conditions higher than 374 °C and 22.1 MPa are required for biomass conversion to gases. Reaction temperature, pressure, feed concentration, residence time and catalyst have prominent roles in gasification. This review focuses on the degradation routes of biomass model compounds such as cellulose and lignin at near and supercritical conditions. Some homogenous and heterogeneous catalysts leading to water-gas shift, methanation and other sub-reactions during supercritical water gasification are highlighted. The parametric impacts along with some reactor configurations for maximum hydrogen production and technical challenges encountered during hydrothermal gasification processes are also discussed. © 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved. Source


Genuis S.J.,University of Calgary | Kelln K.L.,University of Saskatchewan
Behavioural Neurology | Year: 2015

Juxtaposed alongside the ongoing rise in the incidence and prevalence of dementia, is the surge of recent research confirming widespread exposure and bioaccumulation of chemical toxicants. Evidence from sources such as the Centers for Disease Control reveals that most people have accrued varying degrees of assorted toxic pollutants including heavy metals, flame retardants, and pesticide residues within their bodies. It has been well established that many of these toxicants have neurodegenerative as well as neurodevelopmental impact as a result of various pathophysiologic mechanisms including neuronal mitochondrial toxicity and disruption of neurotransmitter regulation. Elimination of stockpiled toxicants from the body may diminish adverse toxicant impact on human biology and allow restoration of normal physiological function. Incorporating a review of medical literature on toxicant exposure and dementia with a case history of a lead-exposed individual diagnosed with dementia, this paper will discuss a much overlooked and potentially widespread cause of declining brain function and dementia. © 2015 Stephen J. Genuis and Kasie L. Kelln. Source


Ferguson G.,University of Saskatchewan
Groundwater | Year: 2015

Heat transfer due to groundwater flow can significantly affect closed geothermal systems. Here, a screening method is developed, based on Peclet numbers for these systems and Darcy's law. Conduction-only conditions should not be expected where specific discharges exceed 10-8m/s. Constraints on hydraulic gradients allow for preliminary screening for advection based on rock or soil types. Identification of materials with very low hydraulic conductivity, such as shale and intact igneous and metamorphic rock, allow for analysis with considering conduction only. Variability in known hydraulic conductivity allows for the possibility of advection in most other rocks and soil types. Further screening relies on refinement of estimates of hydraulic gradients and hydraulic conductivity through site investigations and modeling until the presence or absence of conduction can be confirmed. © 2014, National Ground Water Association. Source


Ferguson G.,University of Saskatchewan
Groundwater | Year: 2015

Injection of wastes into the deep subsurface has become a contentious issue, particularly in emerging regions of oil and gas production. Experience in other regions suggests that injection is an effective waste management practice and that widespread environmental damage is unlikely. Over the past several decades, 23km3 of water has been injected into the Western Canada Sedimentary Basin (WCSB). The oil and gas industry has injected most of this water but large amounts of injection are associated with mining activities. The amount of water injected into this basin during the past century is 2 to 3 orders magnitude greater than natural recharge to deep formations in the WCSB. Despite this large-scale disturbance to the hydrogeological system, there have been few documented cases of environmental problems related to injection wells. Deep injection of waste appears to be a low risk activity based on this experience but monitoring efforts are insufficient to make definitive statements. Serious uncharacterized legacy issues could be present. Initiating more comprehensive monitoring and research programs on the effects of injection in the WCSB could provide insight into the risks associated with injection in less developed sedimentary basins. © 2014, National Ground Water Association. Source


Morozov I.B.,University of Saskatchewan
Journal of Seismology | Year: 2010

Analysis of the frequency dependence of the attenuation coefficient leads to significant changes in interpretation of seismic attenuation data. Here, several published surface-wave attenuation studies are revisited from a uniform viewpoint of the temporal attenuation coefficient, denoted by χ. Theoretically, χ(f) is expected to be linear in frequency, with a generally non-zero intercept γ = χ(0) related to the variations of geometrical spreading, and slope dχ/df = π/Qe caused by the effective attenuation of the medium. This phenomenological model allows a simple classification of χ(f) dependences as combinations of linear segments within several frequency bands. Such linear patterns are indeed observed for Rayleigh waves at 500-100-s and 100-10-s periods, and also for Lg from ~2 s to ~1.5 Hz. The Lgχ(f) branch overlaps with similar linear branches of body, Pn, and coda waves, which were described earlier and extend to ~100 Hz. For surface waves shorter than ~100 s, γ values recorded in areas of stable and active tectonics are separated by the levels of γD ≈ 0.2 \times 10-3s-1 (for Rayleigh waves) and 8 ×10-3 s-1 (for Lg). The recently recognized discrepancy between the values of Q measured from long-period surface waves and normal-mode oscillations could also be explained by a slight positive bias in the geometrical spreading of surface waves. Similarly to the apparent χ, the corresponding linear variation with frequency is inferred for the intrinsic attenuation coefficient, χi, which combines the effects of geometrical spreading and dissipation within the medium. Frequency-dependent rheological or scattering Q is not required for explaining any of the attenuation observations considered in this study. The often-interpreted increase of Q with frequency may be apparent and caused by using the Q-based model of attenuation and following preferred Q(f) dependences while ignoring the true χ(f) trends within the individual frequency bands. © 2010 Springer Science+Business Media B.V. Source


English N.J.,University College Dublin | Tse J.S.,University of Saskatchewan
Physical Review Letters | Year: 2011

The density distributions and fluctuations in grids of varying size in liquid water at ambient pressure, both above the freezing point and in the supercooled state, are analyzed from the trajectories obtained from large-scale molecular dynamics simulations. It is found that the occurrence of low- and high-density regions (LDL and HDL) is transient and their respective residence times are dependent on the size of the simulated system. The spatial extent of density-density correlation is found to be within 7 Å or less. The temporal existence of LDL and HDL arises as a result of natural density fluctuations of an equilibrium system. The density of bulk water at ambient conditions is homogenous. © 2011 American Physical Society. Source


Lam R.S.H.,University of Saskatchewan | Rogers M.A.,Rutgers University
Crystal Growth and Design | Year: 2011

The nucleation activation energy under nonisothermal cooling conditions was determined for 12-hydroxystearic acid (12HSA) (1-D crystals), stearic acid (2-D crystals), and trihydroxystearin (3-D crystals). The relative nucleation rates of trihydroxystearin and stearic acid were inversely proportional to the supercooling-time trajectory parameter (β), while 12HSA was linearly proportional to β. The differences in the proportionality to β are attributed to microscopic versus macroscopic phase separation. This suggests that both stearic acid and trihydroxystearin follow a probability density function for the number of molecules which crystallize as a function of supercooling (i.e., the greater the cooling rate, the greater the number of molecules which are incorporated into the crystal lattice). On the other hand, 12HSA molecules all crystallize when supercooled. The activation energies for stearic acid, 12HSA, trihydroxystearin, and triglycerides were 1.52, 5.40, 7.87, and 24.80 kJ/mol, respectively. The activation energy is partly affected by the polarity of the crystallizing molecules relative to the solvent. As the polarity of the crystallizing molecules increases, the activation energy decreases. However, this was not always observed because the activation energy for stearic acid was less than that of 12HSA. Therefore, the activation energy is not only a function of the molecular polarity but also due to a specific interaction between the nucleating molecules. The specific interaction affects the ability of the polar regions of the molecule to phase separate from the apolar solvent. As 12HSA and stearic acid dimerize, the carboxylic acid regions of the molecule are shielded from the solvent, but 12HSA cannot effectively shield the hydroxyl groups from the crystalline surface, resulting in a higher interfacial tension and, thus, higher activation energy. © 2011 American Chemical Society. Source


Wu F.-X.,University of Saskatchewan
IEEE Transactions on Neural Networks | Year: 2011

Genetic regulatory networks can be described by nonlinear differential equations with time delays. In this paper, we study both locally and globally delay-independent stability of genetic regulatory networks, taking messenger ribonucleic acid alternative splicing into consideration. Based on nonnegative matrix theory, we first develop necessary and sufficient conditions for locally delay-independent stability of genetic regulatory networks with multiple time delays. Compared to the previous results, these conditions are easy to verify. Then we develop sufficient conditions for global delay-independent stability for genetic regulatory networks. Compared to the previous results, this sufficient condition is less conservative. To illustrate theorems developed in this paper, we analyze delay-independent stability of two genetic regulatory networks: a real-life repressilatory network with three genes and three proteins, and a synthetic gene regulatory network with five genes and seven proteins. The simulation results show that the theorems developed in this paper can effectively determine the delay-independent stability of genetic regulatory networks. © 2011 IEEE. Source


Whiting S.J.,University of Saskatchewan | Calvo M.S.,U.S. Food and Drug Administration
Molecular Nutrition and Food Research | Year: 2010

We conducted an examination of recent studies to determine whether older adults (≥65 years) need higher levels of supplementary vitamin D than young adults when attempting to replete vitamin D status in deficient subjects, i.e. those with levels of 25-hydroxyvitamin D less than 75 nmol/L. As data on repletion with vitamin D2 have recently been published, we restricted our discussion to the use of vitamin D3 from dietary supplements, prescriptions for large oral doses, and bolus dosing or injections. Most published dosing regimens failed to achieve 75 nmol/L in most all subjects, whether young adults (<65 years) or older adults (≥65 years). Whether as daily or bolus oral supplementation, elderly subjects appeared to need more vitamin D3 compared with younger adults, however, baseline levels, endpoints, study duration, compliance, and other factors were different among studies. To ensure most subjects are replete in vitamin D, a daily dose of more than 50 μg (2000 IU) in younger and 125 μg (5000 IU) is required. Other strategies including bolus and loading doses are described. No study reported adverse effects of using oral intakes about the current upper level of 50 μg (2000 IU). © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source


Xie K.,Chongqing University | Billinton R.,University of Saskatchewan
IEEE Transactions on Energy Conversion | Year: 2011

The economic and reliability benefits of adding a wind energy conversion system (WECS) to a power system are highly dependent on the wind turbine generator (WTG) installation design, i.e., the type and number of WTG. This paper presents an approach to determine the optimum installation design at each wind site considering the WTG parameters, the total cost of WECS and the power system reliability performance. The model is formulated as a combinatorial constrained optimization problem with a nonlinear, nondifferentiable objective function, which consists of the capital, maintenance and operating costs, and the costumer interruption costs. A number of constraints, including the total installed capacity at a specific wind site and the capital cost, are considered in the model. The model is solved using a genetic algorithm with adaptive crossover and mutation probabilities based on the standard deviation of chromosome fitness in a generation population. The proposed model and algorithm are tested on two power systems. The results show that the proposed approach can be used to obtain the maximum economic and reliability benefits associated with a WECS installation and is a powerful search technique for determining the optimum number and type of WTG considering reliability performance and costs. © 2010 IEEE. Source


Adamko D.J.,University of Alberta | Adamko D.J.,University of Saskatchewan | Sykes B.D.,University of Alberta | Rowe B.H.,University of Alberta
Chest | Year: 2012

Asthma is one of the most common chronic illnesses, especially in children. Reaching the diagnosis of asthma and its management are more difficult than for other chronic illnesses. For example, asthma is a heterogeneous syndrome with many clinical classifications based on patient symptoms, lung function, and response to therapy. The symptoms and objective measurements of lung function, often used to guide therapy, are largely based on the inflammation of the airways. Because measuring airway dysfunction and inflammation in a typical clinical setting is difficult, it is often not done. Metabolomics is the study of small molecules generated from cellular metabolic activity. It is possible that the metabolic profile of a patient with a chronic illness such as asthma is different from that of a healthy patient or from a patient with another respiratory illness. Furthermore, if this metabolome could be measured, it might also vary with disease severity. The pattern of metabolites becomes the diagnostic representing the disease. This article outlines the more recent work that has been done to develop the metabolomic profile of asthma. © 2012 American College of Chest Physicians. Source


Shi Y.,University of Victoria | Fang H.,University of Saskatchewan
International Journal of Control | Year: 2010

We consider the problem of parameter estimation and output estimation for systems in a transmission control protocol (TCP) based network environment. As a result of networked-induced time delays and packet loss, the input and output data are inevitably subject to randomly missing data. Based on the available incomplete data, we first model the input and output missing data as two separate Bernoulli processes characterised by probabilities of missing data, then a missing output estimator is designed, and finally we develop a recursive algorithm for parameter estimation by modifying the Kalman filter-based algorithm. Under the stochastic framework, convergence properties of both the parameter estimation and output estimation are established. Simulation results illustrate the effectiveness of the proposed algorithms. © 2010 Taylor & Francis. Source


Ferguson G.,University of Saskatchewan | Jasechko S.,University of Calgary
Geophysical Research Letters | Year: 2015

Stable isotopes have been used to study large-scale changes in hydrology during the Pleistocene epoch. Many of these efforts have required an estimate of the δ18O value of runoff generated by melting ice sheets. There is no consensus on representative values. Here we examine δ18O values from fossil groundwater samples and isotope-enabled general circulation models (GCMs) to better understand the isotopic composition of the Laurentide Ice Sheet (LIS). Groundwater δ18O values ranged from -12.5 to -25.3‰ and tended to increase southward. The δ18O precipitation values predicted by GCMs follow a similar trend but increase more steeply southward. The difference in groundwater and GCM output can be explained by invoking movement of glacial ice and meltwater, along with mixing within groundwater systems. Most groundwater δ18O values are higher than an average LIS δ18O value of -25.4 ± 2.5‰ calculated based on estimated ice sheet volumes and sea level data. © 2015. American Geophysical Union. All Rights Reserved. Source


Pruitt J.N.,University of Pittsburgh | Ferrari M.C.O.,University of Saskatchewan
Ecology | Year: 2011

Although the study of ecological interactions often takes into account functional variation between species, intraspecific variation is commonly ignored. Here, we investigate the importance of an intraspecific polymorphism in shaping interspecific interactions in a habitat-building species. Colonies of the social spider Anelosimus studiosus provide habitat for dozens of arthropod species, and colony members exhibit markedly polymorphic behavioral temperaments (BT): "aggressive" or "docile." We manipulated the phenotypic compositions of colonies (100% aggressive, 50% aggressive and 50% docile, 100% docile) and measured the nature and magnitude of interactions between A. studiosus and two heterospecific web associates, Larinioides cornutus and Agelenopsis emertoni. We found that BT composition significantly affected the outcome of interspecific interactions, changing the relationship between A. studiosus and its web associates from an ammensalism (where A. studiosus experiences reduced fecundity and survival) to a commensalism or mutualism. Our study successfully illustrates the potential of BTs to impact whole community dynamics, and conversely, for community structure to influence the maintenance of BTs. © 2011 by the Ecological Society of America. Source


Bond A.L.,University of Saskatchewan | Bond A.L.,Center for Conservation Science
Waterbirds | Year: 2016

The diets of gulls (Laridae) can have consequences for reproductive success, chick growth, and survival, yet there have been no quantitative assessments in eastern Newfoundland since the early 1970s. The diet of Herring Gulls (Larus argentatus) was examined through regurgitated prey items and pellets on Gull Island, Witless Bay, Newfoundland and Labrador, Canada, in 2012, and compared with similar data from 1970-1971. There was a significant shift in Herring Gull diet composition from blue mussels (Mytilus edulis) and capelin (Mallotus villosus) in the 1970s to garbage and Common Murre (Uria aalge) eggs in 2012. Delays in capelin spawning and the large increase in breeding Common Murres on Gull Island are likely factors influencing Herring Gull diet. Garbage, which includes human food scraps as well as plastic debris, now constitutes the single largest diet item for Herring Gulls, corresponding with a global increase in plastic pollution. The consistently low contribution of fisheries discards suggests that changes in fishing practices and availability of discards are only one possible factor in the Herring Gull decline in Witless Bay. Source


Marcogliese D.J.,Environment Canada | Pietrock M.,University of Saskatchewan
Trends in Parasitology | Year: 2011

The cumulative effects of multiple stressors are becoming a priority concern for ecotoxicologists, ecologists and conservation biologists working to understand threats to ecosystems and species. In that context, parasites and pathogens are increasingly a focus of attention. Parasites interact with natural and anthropogenic stressors to increase mortality and reduce animal health in myriad ways in a wide spectrum of host and parasite taxa. The combined effects of parasites and other stressors can reduce either resistance or tolerance to infection. Recommendations are provided to guide further research. © 2010. Source


Said N.,University of Western Australia | Kerrich R.,University of Saskatchewan
Precambrian Research | Year: 2010

Three premetamorphic magnesian dyke suites are prominent in the Woolyeneer basalt Formation of the ∼2.7 Ga Kambalda Sequence, Kalgoorlie Terrane, Yilgarn craton, Western Australia: the Butterfly (Mg# 76-70; Ni 640-370 ppm), the Norseman (Mg# 72-66, Ni 1105-1030 ppm), and the Crown (Mg# 73-72, Ni 1240-1170 ppm) Dyke suites. Butterfly Dykes have flat HREE at 6-8 times chondrite, mildly depleted LREE, and Nb/Th > 8; compositionally they resemble high-Mg basalts associated with komatiites and tholeiitic basalts in many Archean greenstone terranes erupted from mantle plumes. Crustally contaminated counterparts have the conjunction of greater (La/Sm)N with Nb/Th < 8. Norseman and Crown suites have composite compositional characteristics: (1) high MgO contents, low Al2O3 and Al2O3/TiO2 ratios, enriched LREE, but fractionated HREE; and (2) positive Nb anomalies, fractionated REE, deep negative P anomalies, and downturn from Pr to Th on primitive mantle normalised diagrams. The former characteristics are of norites, abundant in Neoarchean to Proterozoic intrusions, and interpreted to be melts of low-Al metasomatised continental lithospheric mantle (CLM), whereas the latter characteristics are typical of high-μ ocean island basalts (HIMU-OIB) where the concensus is of ocean crust processed through a subduction zone and recycled into the mantle plume source of HIMU-OIB. Epsilon Nd values of +2.4 to +3.6 are in keeping with a depleted mantle source(s). Accordingly these dyke suites are consistent with melting of depleted continental lithospheric mantle metasomatised by low degree melts from HIMU-OIB. On the Th/Yb versus Nb/Yb discrimination diagram, Butterfly Dykes plot near depleted mantle, and Noresmam and Crown suites within the MORB-OIB array towards the HIMU endmember; consequently, the MORB-OIB array was established in the Archean mantle. Taken with published trace element and Sm-Nd isotope data, the most straightforward geodynamic-magmatic scenario is that the Butterfly Dykes are intrusive equivalents of high-Mg flows in the Kambalda Sequence, erupted from a mantle plume melting at the base of the lithosphere, whereas Norseman and Crown Dyke suites represent melts of metasomatised mantle lithosphere induced by some combination of rifting and thermal input from the plume. © 2010 Elsevier B.V. All rights reserved. Source


Morozov I.B.,University of Saskatchewan
Pure and Applied Geophysics | Year: 2010

Variability of the Earth's structure makes a first-order impact on attenuation measurements which often does not receive adequate attention. Geometrical spreading (GS) can be used as a simple measure of the effects of such structure. The traditional simplified GS compensation is insufficiently accurate for attenuation measurements, and the residual GS appears as biases in both Q0 and η parameters in the frequency-dependent attenuation law Q(f) = Q0fη. A new interpretation approach bypassing Q(f) and using the attenuation coefficient χ(f) = γ + πf/Qe(f) resolves this problem by directly measuring the residual GS, denoted γ, and effective attenuation, Qe. The approach is illustrated by re-interpreting several published datasets, including nuclear-explosion and local-earthquake codas, Pn, and synthetic 50-300-s surface waves. Some of these examples were key to establishing the Q(f) concept. In all examples considered, χ(f) shows a linear dependence on the frequency, γ ≠ 0, and Qe can be considered frequency-independent. Short-period crustal body waves are characterized by positive γSP values of (0.6-2.0) × 10-2 s-1 interpreted as related to the downward upper-crustal reflectivity. Long-period surface waves show negative γLP ≈ -1.9 × 10-5 s-1, which could be caused by insufficient modeling accuracy at long periods. The above γ values also provide a simple explanation for the absorption band observed within the Earth. The band is interpreted as apparent and formed by levels of Qe ≈ 1,100 within the crust decreasing to Qe ≈ 120 within the uppermost mantle, with frequencies of its flanks corresponding to γLP and γSP. Therefore, the observed absorption band could be purely geometrical in nature, and relaxation or scattering models may not be necessary for explaining the observed apparent Q(f). Linearity of the attenuation coefficient suggests that at all periods, the attenuation of both Rayleigh and Love waves should be principally accumulated at the sub-crustal depths (~38-100 km). © 2010 Birkhäuser / Springer Basel AG. Source


Tomlinson D.,Child Health Evaluative Services | Von Baeyer C.L.,University of Saskatchewan | Stinson J.N.,Child Health Evaluative Services | Stinson J.N.,University of Toronto | Sung L.,Child Health Evaluative Services
Pediatrics | Year: 2010

CONTEXT: Numerous faces scales have been developed for the measurement of pain intensity in children. It remains unclear whether any one of the faces scales is better for a particular purpose with regard to validity, reliability, feasibility, and preference. OBJECTIVES: To summarize and systematically review faces pain scales most commonly used to obtain self-report of pain intensity in children for evaluation of reliability and validity and to compare the scales for preference and utility. METHODS: Five major electronic databases were systematically searched for studies that used a faces scale for the self-report measurement of pain intensity in children. Fourteen faces pain scales were identified, of which 4 have undergone extensive psychometric testing: Faces Pain Scale (FPS) (scored 0-6); Faces Pain Scale-Revised (FPS-R) (0 -10); Oucher pain scale (0 -10); and Wong-Baker Faces Pain Rating Scale (WBFPRS) (0-10). These 4 scales were included in the review. Studies were classified by using psychometric criteria, including construct validity, reliability, and responsiveness, that were established a priori. RESULTS: From a total of 276 articles retrieved, 182 were screened for psychometric evaluation, and 127 were included. All 4 faces pain scales were found to be adequately supported by psychometric data. When given a choice between faces scales, children preferred the WBFPRS. Confounding of pain intensity with affect caused by use of smiling and crying anchor faces is a disadvantage of the WBFPRS. CONCLUSIONS: For clinical use, we found no grounds to switch from 1 faces scale to another when 1 of the scales is in use. For research use, the FPS-R has been recommended on the basis of utility and psychometric features. Data are sparse for children below the age of 5 years, and future research should focus on simplified measures, instructions, and anchors for these younger children. Copyright © 2010 by the American Academy of Pediatrics. Source


Jones B.,University of Alberta | Renaut R.W.,University of Saskatchewan
Journal of Sedimentary Research | Year: 2010

Unconsolidated, highly porous, permeable siliceous sediments found in shallow-water pools on the middle and distal parts of Geysir's discharge apron are formed of cryogenic opal-A (COA), opal-A spheres, opal-A cement, silicified microbes, and detrital lithic grains. Silicified leaves and silica-coated grass stems and twigs are locally present with these pool sediments, and microbial mats commonly cover the sediment surface. Partially consolidated layers (< 0.5 cm thick) form when the constituent grains are bound together by filamentous microbes, exopolysaccharides, ana/or opal-A cement. Most components of the sediment can be related to processes that are controlled largely by seasonal variations. Low temperatures in winter promote freezing of the medial to distal discharge waters and lead to formation of COA in ice. When the ice melts, the released COA grains become part of the pool sediments. Microbial mats trap and bind sediment and provide templates for silica precipitation during spring and summer, but become (semi-)dormant during the constant darkness that Iceland experiences during winter. When the waters are sufficiently supersaturated, opal-A precipitates as spheres in the water column and cement in pool deposits. In some pools, seasonal changes are evident from the alternation of "soft" and "hard" (partly cemented) laminae. Elsewhere, however, the distinction between the different time-dependent components is lost because they become superimposed on each other or as aperiodic changes in flow patterns affect different pools. Copyright © 2010, SEPM (Society for Sedimentary Geology). Source


Dmitriev O.Y.,University of Saskatchewan
Biochemistry and Cell Biology | Year: 2011

The Wilson disease protein (ATP7B) is a copper-transporting ATPase that is responsible for regulating copper homeostasis in human tissues. ATP7B is associated with cancer resistance to cisplatin, one of the most widely used anticancer drugs. This minireview discusses the possible mechanisms of tumor resistance to cisplatin mediated by ATP7B. Cisplatin binds to the N-terminal cytosolic domain of ATP7B, which contains multiple copper-binding sites. Active platinum efflux catalyzed by ATP7B is unlikely to significantly contribute to cisplatin resistance in vivo. Transient platinum sequestration in the metal-binding domain followed by transfer to an acceptor protein or a low molecular weight compound is proposed as an alternative mechanism of cisplatin detoxification in the cell. Source


Leslie W.D.,University of Manitoba | Lix L.M.,University of Saskatchewan
Journal of Bone and Mineral Research | Year: 2010

The World Health Organization (WHO) fracture risk assessment system (FRAX) allows for calibration from country-specific fracture data. The objective of this study was to evaluate the method for imputation of osteoporotic fracture rates from hip fractures alone. A total of 38,784 women aged 47.5 years or older at the time of baseline femoral neck bone mineral density (BMD) measurement were identified in a database containing all clinical dual energy X-ray absorptiometry (DXA) results for the Province of Manitoba, Canada. Health service records were assessed for the presence of nontrauma osteoporotic fracture codes after BMD testing (431 hip, 787 forearm, 336 clinical vertebral, and 431 humerus fractures). Ten-year hip and osteoporotic fracture rates were estimated by the Kaplan-Meier method. The population was stratified by age (50 to 90 years, 5-year width strata) and again by femoral neck T-scores (-4.0 to 0.0, 0.5 SD width strata). Within each stratum, the ratio of hip to osteoporotic fractures was calculated and compared with the predicted ratio from FRAX. Increasing age was associated with greater predicted hip-to-osteoporotic ratios (youngest 0.07 versua oldest 0.41) and observed ratios (youngest 0.10 versus oldest 0.48). Lower T-scores were associated with greater predicted (highest 0.04 versus lowest 0.71) and observed ratios (highest 0.06 versus lowest 0.44). There was a strong positive correlation between predicted and observed ratios (Spearman r=0.90-0.97, p<.001). For 14 of the 18 strata, the predicted ratio was within the observed 95% confidence interval (CI). Since collection of population-based hip fracture data is considerably easier than collection of non-hip fracture data, this study supports the current emphasis on using hip fractures as the preferred site for FRAX model calibration. © 2010 American Society for Bone and Mineral Research. Source


Gabrielli C.P.,Oregon State University | McDonnell J.J.,University of Saskatchewan | Jarvis W.T.,Oregon State University
Journal of Hydrology | Year: 2012

Bedrock groundwater dynamics in headwater catchments are poorly understood and poorly characterized. Direct hydrometric measurements have been limited due to the logistical challenges associated with drilling through hard rock in steep, remote and often roadless terrain. We used a new portable bedrock drilling system to explore bedrock groundwater dynamics aimed at quantifying bedrock groundwater contributions to hillslope flow and catchment runoff. We present results from the Maimai M8 research catchment in New Zealand and Watershed 10 (WS10) at the H.J. Andrews Experimental Forest in Oregon, USA. Analysis of bedrock groundwater at Maimai, through a range of flow conditions, revealed that the bedrock water table remained below the soil-bedrock interface, indicating that the bedrock aquifer has minimal direct contributions to event-based hillslope runoff. However, the bedrock water table did respond significantly to storm events indicating that there is a direct connection between hillslope processes and the underlying bedrock aquifer. WS10 groundwater dynamics were dominated by fracture flow. A highly fractured and transmissive zone within the upper one meter of bedrock conducted rapid lateral subsurface stormflow and lateral discharge. The interaction of subsurface stormflow with bedrock storage directly influenced the measured hillslope response, solute transport and computed mean residence time. This research reveals bedrock groundwater to be an extremely dynamic component of the hillslope hydrological system and our comparative analysis illustrates the potential range of hydrological and geological controls on runoff generation in headwater catchments. © 2012 Elsevier B.V. Source


Seshia S.S.,University of Saskatchewan
Journal of Evaluation in Clinical Practice | Year: 2015

Background The Users' Guides to the Medical Literature Manual has been a major influence on the teaching and practice of health care globally. Methods The 3rd edition of the multi-authored Manual was reviewed using the principles outlined in Evidence-based Medicine (EBM) texts. One 'clinical scenario' was selected for critical appraisal, as were several chapters; objectivity was enhanced by citing references to support opinions. Results (summary of the appraisal) (1) Strengths: Clinical pearls, too numerous to list. Examples: (i) evidence is never enough to drive clinical decision making; (ii) do not rush to adopt new interventions; and (iii) question efficacy data based only on surrogate markers. (2) Weaknesses: The Manual shares shortcomings of textbooks discussed by Straus et al.: (i) references may not be current, important ones may be excluded and citations may be selective; (ii) often, opinion-based; and (iii) delays between revisions. (3) Notable omissions: Little or no discussion of: (i) important segments of the population: those <18 years of age, >65 years of age and those with multimorbidity; (ii) surgical disciplines; (iii) Greenhalgh et al.'s essay on EBM; (iv) alternate views on the hierarchy of evidence; and (vi) critical thinking. (4) Additional issues: (i) Omission of important references on dabigatran (clinical scenario: chapter 13.1); (ii) authors' advice (Chapter 13.3) to 'bypass the discussion section of published research'; and (iii) the advocacy of pre-appraised sources of evidence and network meta-analysis without warnings about limitations, are critiqued. Conclusion The Manual has several clinical pearls but readers should also be aware of shortcomings. © 2016 John Wiley & Sons, Ltd. Source


Patrick R.J.,University of Saskatchewan
Water International | Year: 2011

This paper explores the methodological and organizational feasibility of conducting a water soft path study for Saskatchewan. Arguably, the methodology for soft path analysis is well developed and data availability for such a study in Saskatchewan is comparatively good. Given the many pressures on water resources in Saskatchewan, the timing is opportune for setting a different path for a water future in this prairie province that will enhance water security. A soft path for water may provide the means for such a future. © 2011 Copyright 2011 International Water Resources Association. Source


Steelman T.A.,University of Saskatchewan | McCaffrey S.,Us Forest Service Northern Research Station
Natural Hazards | Year: 2013

As societies evolve, often the most appropriate response to the hazard must also evolve. However, such shifts in appropriate response to a hazard, whether at the individual or at the societal level, are rarely straightforward: Closing the gap between desired practice and current practice requires effective communication. Although there is a significant literature on how to encourage adaptation before an event and how to communicate during an event, there is less work tying the two together or on how to communicate shifts in larger scale societal response to a natural hazard. In this article, we bring together the best practices and theoretical literature from risk communication and crisis communication and empirical literature on wildfire communication to derive the key characteristics associated with best communication practices. We then use this framework on three case studies of wildfires in California, Montana, and Wyoming, each of which used a different strategy for managing the fire, to understand whether approaching communication more holistically can lead to more desired natural hazard management outcomes. Our working hypothesis was as follows: effective communication before and during a fire would be associated with acceptance of more flexible fire management strategies. The findings indicate how a type of desired management change (more flexible fire management) is associated with more effective communication practices before and during the event. © 2012 Springer Science+Business Media B.V. Source


The impacts of exercise and physical activity on healthcare utilization of older adults have been studied using either (1) clinical trials or retrospective cohort studies focusing on older people who participated in various exercise intervention programs, or (2) survey data. This review focuses on both streams of studies, which cover the topic for adults aged 65 and older. The paper reviews the literature on physical activity and its implications for healthcare system, and discusses potential directions for future research by highlighting the limitations of the existing studies. Although there are significant variations in samples and methods used, both streams of reviewed literature provide evidence that physical activity leads to lower utilization of healthcare services. Given differences in methods and samples in these studies, estimated effect of physical activity on healthcare utilization shows significant variation from one study to another. These results, therefore, cannot be generalized to justify population wide exercise intervention programs for older adults. Additional studies are needed to provide more robust estimates for the effects of exercise, and to examine the feasibility of population wide policies that aim to encourage participation of older adults in physical activity. © 2011 Elsevier Ireland Ltd. All rights reserved. Source


Munoz-Villers L.E.,Oregon State University | Munoz-Villers L.E.,National Autonomous University of Mexico | McDonnell J.J.,Oregon State University | McDonnell J.J.,University of Saskatchewan
Water Resources Research | Year: 2012

Most studies to date in the humid tropics have described a similar pattern of rapid translation of rainfall to runoff via overland flow and shallow subsurface stormflow. However, study sites have been few overall, and one particular system has received very little attention so far: tropical montane cloud forests (TMCF) on volcanic substrate. While TMCFs provide critical ecosystem services, our understanding of runoff generation processes in these environments is limited. Here, we present a study aimed at identifying the dominant water sources and pathways and mean residence times of soil water and streamflow for a first-order, TMCF catchment on volcanic substrate in central eastern Mexico. During a 6-week wetting-up cycle in the 2009 wet season, total rainfall was 1200 mm and storm event runoff ratios increased progressively from 11 to 54%. With the increasing antecedent wetness conditions, our isotope and chemical-based hydrograph separation analysis showed increases of pre-event water contributions to the storm hydrograph, from 35 to 99%. Stable isotope-based mean residence times estimates showed that soil water aged only vertically through the soil profile from 5 weeks at 30 cm depth to 6 months at 120 cm depth. A preliminary estimate of 3 years was obtained for base flow residence time. These findings all suggest that shallow lateral pathways are not the controlling processes in this tropical forest catchment; rather, the high permeability of soils and substrate lead to vertical rainfall percolation and recharge of deeper layers, and rainfall-runoff responses appeared to be dominated by groundwater discharge from within the hillslope. © 2012. American Geophysical Union. Source


Adamowicz W.,University of Alberta | Dupont D.,Brock University | Krupnick A.,Senior Fellow and Director of Research | Zhang J.,University of Saskatchewan
Journal of Environmental Economics and Management | Year: 2011

We examine the value of health risk reductions (microbial illnesses/deaths and bladder cancer illnesses/deaths) in the context of drinking water quality treatment by public systems. When we assume that combined mortality and morbidity risk reductions are equally spread in the future; our results suggest that microbial risk-reduction programs have higher value than cancer risk-reduction programs, but that mortality risk reduction values are not significantly different for cancer and microbials. However, when a 25-year cancer latency is accounted for and a 5% discount rate is used, the value of cancer mortality risk reductions exceeds the value for microbial risk reductions. We also address a number of methodological issues, including performance of alternative choice experiment estimation (CE) techniques, relationship of CE to contingent valuation results, and implications for incorporating morbidity and mortality endpoints in the same survey instrument. © 2010 Elsevier Inc. Source


Dahl C.,University of Saskatchewan
Journal of Electronic Resources Librarianship | Year: 2012

The development of patron-driven acquisition (PDA) as a viable collections practice is encouraging many academic libraries to be proactive about sharing significant collection development responsibilities with their patrons. The adoption of PDA represents a challenge to some long-held understandings about libraries and collections, however, and some libraries are still assessing this option. Further, questions about PDA and its fit with academic libraries are just now being answered. An examination of some of the shifting understandings in this area of librarianship and their relation to PDA provides a snapshot of the big picture, which may assist libraries with the decision-making process. © 2012 Copyright Taylor and Francis Group, LLC. Source


Farnese P.L.,University of Saskatchewan
Transnational Environmental Law | Year: 2014

Despite widespread recognition of the threat posed by emerging zoonotic diseases (EZDs) to human and animal health and the economy, the root causes of EZDs are largely ignored by the international community. In particular, the links between wildlife health, human-induced land-use change, and EZDs have not been adequately addressed. Generally, states are not required to evaluate the health impacts of land-use decisions within their territories. Similarly, global efforts to protect wild spaces are rarely identified as a health imperative. Where initiatives have been undertaken, they remain focused largely on detecting and controlling only those wildlife diseases that are known or suspected to be a threat to human and animal health or the economy. A critique of the existing international responses leaves no doubt that a preventative approach must be adopted to address human vulnerability to EZDs. Copyright © Cambridge University Press 2014. Source


Dahl W.J.,University of Florida | Foster L.M.,University of Florida | Tyler R.T.,University of Saskatchewan
British Journal of Nutrition | Year: 2012

Pulses, including peas, have long been important components of the human diet due to their content of starch, protein and other nutrients. More recently, the health benefits other than nutrition associated with pulse consumption have attracted much interest. The focus of the present review paper is the demonstrated and potential health benefits associated with the consumption of peas, Pisum sativum L., specifically green and yellow cotyledon dry peas, also known as smooth peas or field peas. These health benefits derive mainly from the concentration and properties of starch, protein, fibre, vitamins, minerals and phytochemicals in peas. Fibre from the seed coat and the cell walls of the cotyledon contributes to gastrointestinal function and health, and reduces the digestibility of starch in peas. The intermediate amylose content of pea starch also contributes to its lower glycaemic index and reduced starch digestibility. Pea protein, when hydrolysed, may yield peptides with bioactivities, including angiotensin I-converting enzyme inhibitor activity and antioxidant activity. The vitamin and mineral contents of peas may play important roles in the prevention of deficiency-related diseases, specifically those related to deficiencies of Se or folate. Peas contain a variety of phytochemicals once thought of only as antinutritive factors. These include polyphenolics, in coloured seed coat types in particular, which may have antioxidant and anticarcinogenic activity, saponins which may exhibit hypocholesterolaemic and anticarcinogenic activity, and galactose oligosaccharides which may exert beneficial prebiotic effects in the large intestine. © 2012 The Authors. Source


Morozov I.B.,University of Saskatchewan
Annals of Geophysics | Year: 2011

In several recent reports, we have explained the frequency dependence of the apparent seismic quality-factor (Q) observed in many studies according to the effects of geometrical attenuation, which was defined as the zerofrequency limit of the temporal attenuation coefficient. In particular, geometrical attenuation was found to be positive for most waves traveling within the lithosphere. Here, we present three theoretical models that illustrate the origin of this geometrical attenuation, and we investigate the causes of its preferential positive values. In addition, we discuss the physical basis and limitations of both the conventional and new attenuation models. For waves in media with slowly varying properties, geometrical attenuation is caused by variations in the wavefront curvature, which can be both positive (for defocusing) and negative (for focusing). In media with velocity/density contrasts, incoherent reflectivity leads to geometrical-attenuation coefficients which are proportional to the mean squared reflectivity and are always positive. For «coherent» reflectivity, the geometrical attenuation is approximately zero, and the attenuation process can be described according to the concept of «scattering Q». However, the true meaning of this parameter is in describing the mean reflectivity within the medium, and not that of the traditional resonator quality factor known in mechanics. The general conclusion from these models is that non-zero and often positive levels of geometrical attenuation are common in realistic, heterogeneous media, both observationally and theoretically. When transformed into the conventional Q-factor form, this positive geometrical attenuation leads to Q values that quickly increase with frequency. These predictions show that the positive frequency-dependent Q observed in many datasets might represent artifacts of the transformations of the attenuation coefficients into Q. © 2011 by the Istituto Nazionale di Geofisica e Vulcanologia. Source


Bo G.A.,Institute Reproduccion Animal Cordoba IRAC | Bo G.A.,National University of Villa Maria | Mapletoft R.J.,University of Saskatchewan
Theriogenology | Year: 2014

Superovulation protocols have evolved greatly over the past 40 to 50 years. The development of commercial pituitary extracts and prostaglandins in the 1970s, and partially purified pituitary extracts and progesterone-releasing devices in the 1980s and 1990s have provided for the development of many of the protocols that we use today. Furthermore, the knowledge of follicular wave dynamics through the use of real-time ultrasonography and the development of the means by which follicular wave emergence can be controlled have provided new practical approaches. Although some embryo transfer practitioners still initiate superstimulatory treatments during mid-cycle in donor cows, the elective control of follicular wave emergence and ovulation has had a great effect on the application of on-farm embryo transfer, especially when large groups of donors need to be superstimulated at the same time. The most common treatment for the synchronization of follicular wave emergence for many years has been estradiol and progestins. In countries where estradiol cannot be used, practitioners have turned to alternative treatments for the synchronization of follicle wave emergence, such as mechanical follicle ablation or the administration of GnRH to induce ovulation. An approach that has shown promise is to initiate FSH treatments at the time of the emergence of the new follicular wave after GnRH-induced ovulation of an induced persistent follicle. Alternatively, it has been suggested recently that it might be possible to ignore follicular wave status, and by extending the treatment protocol, induce small antral follicles to grow and superovulate. Recently, the mixing of FSH with sustained release polymers or the development of long-acting recombinant FSH products have permitted superstimulation with a single or alternatively, two gonadotropin treatments 48 hours apart, reducing the need for animal handling during superstimulation. Although the number of transferable embryos per donor cow superstimulated has not increased, the protocols that are used today have increased the numbers of transferable embryos recovered per unit time and have facilitated the application of on-farm embryo transfer programs. They are practical, easy to administer by farm personnel, and more importantly, they eliminate the need for detecting estrus. © 2014 Elsevier Inc. Source


Prasad K.,University of Saskatchewan
International Journal of Angiology | Year: 2014

Advanced glycation end products (AGEs) interact with the receptor for AGEs (RAGE) on the membrane and induce deleterious effects via activation of nuclear factor kappa-B, and increased oxidative stress and inflammatory mediators. AGEs also combine with circulating soluble receptors (endogenous secretory RAGE [esRAGE] and soluble receptor for RAGE [sRAGE]) and sequester RAGE ligands and act as a cytoprotective agent. esRAGE is secreted from the cells and is a spliced variant of RAGE. The sRAGE on the other hand is proteolytically cleaved from cell surface receptor via matrix metalloproteinase (MMPs). sRAGE is elevated in type 1 and type 2 diabetes and in patients with decreased renal function. Serum levels of sRAGE are reduced in diseases including coronary artery disease, atherosclerosis, essential hypertension, chronic obstructive lung disease, heart failure, and hypercholesterolemia. Serum levels of AGEs are elevated in patients with coronary artery disease and atherosclerosis. However, the increases in serum AGEs are very high in patients with diabetes and renal disease. There is a positive correlation between serum levels of AGEs and RAGE and sRAGE. The elevated levels of sRAGE in patients with diabetes and impaired renal function may be due to increased levels of MMPs. AGEs increase in the expression and production of MMPs, which would increase the cleavage of sRAGE from cell surface. In conclusion, low level of serum sRAGE is a good biomarker for disease other than diabetes and renal disease. A unified formula that takes into consideration of AGEs, sRAGE, and esRAGE such as AGE/sRAGE or AGEs/esRAGE would be better biomarker than sRAGE or esRAGE for all AGE-RAGE-associated diseases including diabetes and renal disease. Copyright © 2014 by Thieme Medical Publishers, Inc., 333 Seventh Avenue, New York, NY 10001, USA. Source


Cheviakov A.F.,University of Saskatchewan | Ward M.J.,University of British Columbia | Straube R.,Max Planck Institute for Dynamics of Complex Technical Systems
Multiscale Modeling and Simulation | Year: 2010

The mean first passage time (MFPT) is calculated for a Brownian particle in a spherical domain in R3 that contains N small non over lapping absorbing windows, or traps, on its boundary. For the unit sphere, the method of matched asymptotic expansions is used to derive an explicit three-term asymptotic expansion for the MFPT for the case of N small locally circular absorbing windows. The third term in this expansion, not previously calculated, depends explicitly on the spatial configuration of the absorbing windows on the boundary of the sphere. The three term asymptotic expansion for the average MFPT is shown to be in very close agreement with full numerical results. The average MFPT is shown to be minimized for trap configurations that minimize a certain discrete variational problem. This variational problem is closely related to the well-known optimization problem of determining the minimum energy configuration for N repelling point charges on the unit sphere. Numerical results, based on global optimization methods, are given for both the optimum discrete energy and the arrangements of the centers {x1, . . . , xN} of N circular traps on the boundary of the sphere. A scaling law for the optimum discrete energy, valid for N≫ 1, is also derived. copyright copyright © 2010 Society for Industrial and Applied Mathematics. Source


Andrianov A.K.,Apogee Technology Inc. | Mutwiri G.,University of Saskatchewan
Vaccine | Year: 2012

A vast number of studies explore the potential of intradermal immunization, its role in the developing of new and improved vaccines and providing access to them globally. The advancement of microneedle technology offers new avenues for the practical realization of this approach, but, on certain instances, introduces new limitations and challenges in the formulation development, which involve the concern over its compatibility with existing and emerging immunoadjuvants. The present paper attempts to review various aspects of immunoadjuvant enhanced microneedle immunization and focuses on the potential of synthetic biomaterials that can play a multifunctional role in such approach. PCPP, a synthetic polyphosphazene macromolecular compound, is discussed as an example of such material that can potentially enable the technology as a microfabrication agent and a potent intradermal immunoadjuvant. © 2011 Elsevier Ltd. Source


English N.J.,University College Dublin | Tse J.S.,University of Saskatchewan
Journal of Physical Chemistry Letters | Year: 2014

The thermal conductivity of both supercooled and ambient-temperature water at atmospheric pressure has been computed over the 140-270 K temperature range for three popular water models via equilibrium molecular dynamics in the Green-Kubo setting. No strong temperature dependence of thermal conductivity was observed. The underlying phonon modes contributing to thermal conduction processes have been examined in the present work, and it has been established that (translational) acoustic modes dominate in supercooled water. (Graph Presented). © 2014 American Chemical Society. Source


Andrews D.A.,Carleton University | Bonta J.,Public Safety Canada | Wormith J.S.,University of Saskatchewan
Criminal Justice and Behavior | Year: 2011

The risk-need-responsivity (RNR) model has been widely regarded as the premier model for guiding offender assessment and treatment. The RNR model underlies some of the most widely used risk-needs offender assessment instruments, and it is the only theoretical model that has been used to interpret the offender treatment literature. Recently, the good lives model (GLM) has been promoted as an alternative and enhancement to RNR. GLM sets itself apart from RNR by its positive, strengths-based, and restorative model of rehabilitation. In addition, GLM hypothesizes that enhancing personal fulfillment will lead naturally to reductions in criminogenic needs, whereas RNR posits the reverse direction. In this article the authors respond to GLM's criticisms of RNR and conclude that little substance is added by GLM that is not already included in RNR, although proponents of RNR may learn from the popular appeal that GLM, with its positive, strength-based focus, has garnered from clinicians over the past decade. © 2011 International Association for Correctional and Forensic Psychology. Source


Rose Olfert M.,University of Saskatchewan | Partridge M.D.,Ohio State University
Growth and Change | Year: 2010

The combination of less than perfectly mobile resources (human and other), pervasive urbanization trends with potentially significant (positive and negative) externalities, and an environment of fiscal restraint suggests the need for more effective rural development and policy. In contrast to historical sectoral or fad-based policies, place-based rural development programs and policies focus on rural populations in the context of a realistic assessment of the opportunities and constraints they face. Among the most promising opportunities are 1) improving integration (possibly through connective infrastructure) with urban economies in order to access agglomeration economies, 2) enhancing rural amenities, and 3) increasing entrepreneurial capacity. © 2010 Copyright the Authors. Journal compilation © 2010 Wiley Periodicals, Inc. Source


Zhang H.,University of Victoria | Shi Y.,University of Victoria | Mehr A.S.,University of Saskatchewan
International Journal of Adaptive Control and Signal Processing | Year: 2011

In this paper, we investigate the robust weighted Hinf; filtering problem for networked systems with intermittent measurements under the discrete-time framework. Multiple outputs of the plant are measured by separate sensors, each of which has a specific failure rate. Network-induced delay, packet dropouts and network-induced disorder phenomena are all incorporated in the modeling of the network link. The resulting closed-loop system involves both delayed noise and non-delayed noise. In order to make full use of the delayed information, we define a weighted Hinf; performance index. Sufficient delay-dependent and parameter-dependent conditions for the existence of the filter and the solvability of the addressed problem are given via a set of linear matrix inequalities. Two simulation examples are presented to illustrate the relationship between the minimal performance level and the weighting factor, which show the effectiveness of the proposed method. Copyright © 2010 John Wiley & Sons, Ltd. Source


Olver M.E.,University of Saskatchewan | Wong S.,University of Nottingham
Psychology, Crime and Law | Year: 2011

We examined sex offender treatment dropout predictors, in particular, the relationship of psychopathy and sex offender risk to treatment dropout in a sample of 154 federally incarcerated sex offenders treated in a high intensity sex offender treatment program. Demographic, criminal history, mental health and treatment-related data as well as data on risk assessment measures including the Static 99, Violence Risk Scale - Sexual Offender version (VRS-SO), and Psychopathy Checklist - Revised (PCL-R) were collected. Logistic regression and discriminant function analyses were used to identify predictors that made significant and unique contributions to dropout among all the variables under study. The Emotional facet of Factor 1 of the PCL-R and never being married were found to be the most salient predictors of treatment dropout and correctly identified about 70% of the cases. The implications of the findings for managing treatment dropout and for the treatment of psychopathic offenders are discussed. © 2011 Taylor & Francis. Source


Bokharaiee S.,University of Manitoba | Nguyen H.H.,University of Saskatchewan | Shwedyk E.,University of Manitoba
IEEE Transactions on Vehicular Technology | Year: 2011

Given the ever-growing demand for radio spectrum, cognitive radio has recently emerged as an attractive wireless technology. Since orthogonal frequency-division multiplexing (OFDM) is one of the major wideband transmission techniques, detection of OFDM signals in low-signal-to-noise-ratio scenario is an important research problem. In this paper, it is shown that cyclic prefix (CP) correlation coefficient (CPCC)-based spectrum sensing, which was previously introduced as a simple and computationally efficient spectrum-sensing method for OFDM signals, is a special case of the constrained generalized likelihood ratio test (GLRT) in the absence of multipath. As such, the performance of this algorithm degrades in a multipath scenario, where OFDM is usually implemented. Furthermore, by considering multipath correlation in the GLRT algorithm and employing the inherent structure of OFDM signals, a simple and low-complexity algorithm called the multipath-based constrained-GLRT (MP-based C-GLRT) algorithm is obtained. The MP-based C-GLRT algorithm is shown to outperform the CPCC-based algorithm in a rich multipath environment. Further performance improvement can be achieved by simply combining both the CPCC- and MP-based C-GLRT algorithms. A simple GLRT-based detection algorithm is also developed for unsynchronized OFDM signals, whose performance is only slightly degraded when compared with the synchronized detection in a rich multipath environment. © 2011 IEEE. Source


Cho S.H.,Korea University | Burton R.,University of Saskatchewan
Mechatronics | Year: 2011

This paper deals with the issue of position tracking control of a high performance hydrostatic actuation system using simple adaptive control. For energy-efficiency and savings, a speed-controlled fixed displacement pump is utilized to drive a symmetrical linear actuator instead of a directional control servo valve. The whole control system is composed of a pair of interconnected subsystems, that is, a feedback control system and a feedforward control system to enhance the tracking performance. The experiment using the proposed control scheme has been performed and a significant reduction in position tracking error is achieved compared to a conventional PID control. © 2010 Elsevier Ltd. All rights reserved. Source


Asgari G.,Hamadan University of Medical Sciences | Roshani B.,University of Saskatchewan | Ghanizadeh G.,Baqiyatallah Medical Sciences University
Journal of Hazardous Materials | Year: 2012

In this research work, pumice that is functionalized by the cationic surfactant, hexadecyltrimethyl ammonium (HDTMA), is used as an adsorbent for the removal of fluoride from drinking water. This work was carried out in two parts. The effects of HDTMA loading, pH (3-10), reaction time (5-60min) and the adsorbent dosage (0.15-2.5gL -1) were investigated on the removal of fluoride as a target contaminate from water through the design of different experimental sets in the first part. The results from this first part revealed that surfactant-modified pumice (SMP) exhibited the best performance at dose 0.5gL -1, pH 6, and it adsorbs over 96% of fluoride from a solution containing 10mgL -1 fluoride after 30min of mixing time. The four linear forms of the Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherms model were applied to determine the best fit of equilibrium expressions. Apart from the regression coefficient (R 2), four error functions were used to validate the isotherm and kinetics data. The experimental adsorption isotherm complies with Langmuir equation model type 1. The maximum amount of adsorption (Q max) was 41mgg -1. The kinetic studies indicated that the adsorption of fluoride best fitted with the pseudo-second-order kinetic type 1. Thermodynamic parameters evaluation of fluoride adsorption on SMP showed that the adsorption process under the selected conditions was spontaneous and endothermic. The suitability of SMP in defluoridation at field condition was investigated with natural groundwater samples collected from a nearby fluoride endemic area in the second part of this study. Based on this study's results, SMP was shown to be an affordable and a promising option for the removal of fluoride in drinking water. © 2012 Elsevier B.V. Source


Walker R.,University of Saskatchewan | Barcham M.,Australian National University
Environment and Planning A | Year: 2010

Indigenous peoples in Canada, New Zealand, and Australia are highly urbanised. In spite of this, urban Indigenous communities have a difficult time giving effect to self-determining autonomy in comparison with their rural, remote, and reserve counterpart communities. The place of authentic Indigeneity in the public perception has remained outside of urban areas. All three countries have had social housing initiatives that aim to even out life-chances among citizens. How Indigeneity features in the housing sector varies from country to country. Through an examination of social housing developments from the 1930s to the present, we develop knowledge of how the place of authentic Indigeneity has changed over time and has been linked to the creation of Indigenous-inclusive citizenship in the city. While the Canadian experience continues to pair self-government with com- mon social housing goals, New Zealand never really linked self-government with common social citizenship in the housing sector; Australia did for a time, but it is regressing quickly. © 2009 Pion Ltd and its Licensors. Source


Johnstone J.F.,University of Saskatchewan | Johnstone J.F.,University of Alaska Fairbanks | Hollingsworth T.N.,University of Alaska Fairbanks | Chapin F.S.,University of Alaska Fairbanks | Mack M.C.,University of Florida
Global Change Biology | Year: 2010

Predicting plant community responses to changing environmental conditions is a key element of forecasting and mitigating the effects of global change. Disturbance can play an important role in these dynamics, by initiating cycles of secondary succession and generating opportunities for communities of long-lived organisms to reorganize in alternative configurations. This study used landscape-scale variations in environmental conditions, stand structure, and disturbance from an extreme fire year in Alaska to examine how these factors affected successional trajectories in boreal forests dominated by black spruce. Because fire intervals in interior Alaska are typically too short to allow relay succession, the initial cohorts of seedlings that recruit after fire largely determine future canopy composition. Consequently, in a dynamically stable landscape, postfire tree seedling composition should resemble that of the prefire forest stands, with little net change in tree composition after fire. Seedling recruitment data from 90 burned stands indicated that postfire establishment of black spruce was strongly linked to environmental conditions and was highest at sites that were moist and had high densities of prefire spruce. Although deciduous broadleaf trees were absent from most prefire stands, deciduous trees recruited from seed at many sites and were most abundant at sites where the fires burned severely, consuming much of the surface organic layer. Comparison of pre- and postfire tree composition in the burned stands indicated that the expected trajectory of black spruce self-replacement was typical only at moist sites that burned with low fire severity. At severely burned sites, deciduous trees dominated the postfire tree seedling community, suggesting these sites will follow alternative, deciduous-dominated trajectories of succession. Increases in the severity of boreal fires with climate warming may catalyze shifts to an increasingly deciduous-dominated landscape, substantially altering landscape dynamics and ecosystem services in this part of the boreal forest. © 2009 Blackwell Publishing Ltd. Source


Fidler C.,University of Saskatchewan
Environment, Development and Sustainability | Year: 2010

While the role Aboriginal people play in environmental governance programs are often underpinned by the Crown, Aboriginal peoples are ratifying negotiated agreements with mining proponents to ensure their issues and concerns are addressed. This paper examines Aboriginal participation in mine development to show how more inclusive social and environmental development models can support a more sustainable development. Through two complementary processes, negotiated agreements and environmental impact assessment, Aboriginal peoples are maximizing their benefits and minimizing the adverse impacts of a project to create a more sustainable resource development. Case study analysis of the Galore Creek Project in northwestern British Columbia, Canada, illustrates how environmental impact assessment and negotiated agreements can co-exist to positively contribute to a successful mineral development, and hence operationalize sustainability within this context. © Springer Science+Business Media B.V. 2009. Source


Bialer M.,Hebrew University of Jerusalem | Midha K.K.,University of Saskatchewan
Epilepsia | Year: 2010

Most antiepileptic drugs (AEDs) are currently available as generic products, yet neurologists and patients are reluctant to switch to generics. Generic AEDs are regarded as bioequivalent to brand AEDs after meeting the average bioequivalence criteria; consequently, they are considered to be interchangeable with their respective brands without loss of efficacy and safety. According to the U.S. Food and Drug Administration (FDA) the present bioequivalence requirements are already so rigorous and constrained that there is little possibility that generics that meet regulatory bioequivalence criteria could lead to therapeutic problems. So is there a scientific rationale for the concerns about switching patients with epilepsy to bioequivalent generics? Herein we discuss the assessment of bioequivalence and propose a scaled-average bioequivalence approach where scaling of bioequivalence is carried out based on brand lot-to-lot variance as an alternative to the conventional bioequivalence test as a means to determine whether switching patients to generic formulations, or vice versa, is a safe and effective therapeutic option. Meeting the proposed scaled-average bioequivalence requirements will ensure that when an individual patient is switched, he or she has fluctuations in plasma levels similar to those from lot-to-lot of the brand reference levels and thus should make these generic products safely switchable without change in efficacy and safety outcomes. © 2010 International League Against Epilepsy. Source


Stroujkova A.,Weston Geophysical Corp. | Morozov I.,University of Saskatchewan
Bulletin of the Seismological Society of America | Year: 2014

Nuclear explosion monitoring is commonly performed at regional or teleseismic distances, and consequently the spectra of the recorded seismic waves are significantly affected by the propagation path. Study of the explosion-source signature requires separation of the source and the propagation effects. In this article, we analyze the data from two chemical explosions (54 kg and 123 kg of ammonium nitrate and fuel oil) conducted in central New Hampshire. We use small calibration explosions (0.454 kg Composition B boosters) to remove the propagation effects and to extract the source time functions (STFs) for the larger explosions using the empirical Green's function method. Comparison of the deconvolved signals with the Mueller-Murphy model (Mueller and Murphy, 1971) shows that the observed STFs have significantly longer duration than the characteristic time scale predicted by the model. Source-function period increase can be attributed to differences between nuclear and chemical sources. Alternatively, it can be explained by nonlinear attenuation effects near the source of shallow explosions. Source


Predation produces strong selection on numerous traits affecting prey survival, such as morphology or behaviour. However, little is known about the influence of predation on behavioural traits that reflect cognitive abilities. Two studies have shown negative relationships between predation pressure and performance in foraging-related tasks in different populations of fish. Whether these differences are due to population differences or plasticity is unknown. In addition, little is known of the effect of predation risk on predator-related cognitive function. Here, I exposed woodfrog, Lithobates sylvaticus, tadpoles to a high or low level of background risk using injured conspecific cues for 4 days. Following this period, I conditioned them to recognize a novel predator as a threat. I compared the intensity of the learned response between the two groups the following day, and compared retention after 10 days. I found that high-risk tadpoles learned to respond to the predator with a greater intensity of antipredator response and retained the response longer compared to low-risk tadpoles. This is the first study to demonstrate that recent history of predation risk can affect the cognition of prey, demonstrating plasticity in a relatively fixed learning mechanism. My results also raise questions regarding the existence of cross-contextual cognitive trade-offs in animals: increased cognition in predation-related tasks may come at the expense of foraging-related tasks. © 2014 The Association for the Study of Animal Behaviour. Source


Karami E.,University of Saskatchewan
International Journal of Communication Systems | Year: 2013

In this paper, the performance of decision directed (DD) maximum likelihood (ML) channel tracking algorithm is analyzed. The ML channel tracking algorithm presents efficient performance especially in the decision directed mode of the operation. In this paper, after introducing the method for analysis of DD algorithms, the performance of ML MIMO channel tracking algorithm in the DD mode of operation is analyzed. In this method channel tracking error is evaluated for a given decision error rate. Then, the decision error rate is approximated for a given channel tracking error. By solving these two derived equations jointly, both the decision error rate and the channel tracking error are computed. The presented analysis is compared with simulation results for different channel ranks, Doppler frequency shifts, and signal-to-noise ratios, and it is shown that the analysis is a good match for simulation results especially in high rank MIMO channels and high Doppler shifts. Copyright © 2012 John Wiley & Sons, Ltd. Source


Mondol J.-A.M.,University of Saskatchewan
IEEE Pacific RIM Conference on Communications, Computers, and Signal Processing - Proceedings | Year: 2011

Cloud computing allows accessibility and efficient use of the global data ware houses and IT resources to different clients based on their need on the software, platform or infrastructure layer. Irrespective of the different levels of cloud computing service and attributes- customers are withdrawn from its mass usage due to cloud computing security issues. Cloud computing security issues if resolved can jump start cloud computing as the de-facto solution towards computation. From individual consumer to large enterprises - a secure cloud computing infrastructure can serve all clients anywhere and everywhere. Within the body of this research a new strategy towards delivering cloud computing security using reconfigurable computing has been presented. Components of the cloud vendor and cloud client trust mechanisms have been extrapolated from software based solutions to the hardware. Using FPGAs four different types of solutions are being proposed to ensure user authentication and user data security. These four solutions are trusted cloud computing platform for ensuring computational trust, user enabled security groups for data collaboration, data security and verifiable attestation. All four of these solutions implemented together can allow trusted computing that allows collaboration while keeping data secure within a computation environment that is continuously being attested for security measures. © 2011 IEEE. Source


The primary objective of this study was to identify herd management and cow characteristics that are associated with abortion in cow-calf herds in Western Canada. Reproductive events were closely monitored in 29,713 cows in 203 herds from the beginning of the breeding season in 2001 through the calving season in 2002. Herd management and cow-level risk factors such as age, body condition score, and previous reproductive history were measured through a series of herd visits by project personnel and detailed individual animal records maintained by the herd owner. Pregnancy status was assessed in fall of 2001 by the herd veterinarian. Cows most likely to abort were replacement heifers, cows that were more than 10years of age, cows with a body condition score of less than or equal to or 5 of 9 at pregnancy testing, or with twin pregnancies. Cows vaccinated for bovine viral diarrhea virus and infectious bovine rhinotracheitis and bred on community pastures were less likely to abort than cows from community pastures that were not vaccinated. Cows bred on community pastures that were not vaccinated were also more likely to abort than cows that were not on community pastures regardless of vaccination status. Adverse calving-associated events such as severe dystocia, problems such as uterine prolapse or retained placentas, abortion or calf death within 1hour of birth were also associated with an increased risk of abortion the subsequent calving season after accounting for all other factors. © 2014 Elsevier Inc. Source


Bortolotti G.R.,University of Saskatchewan
Ecological Applications | Year: 2010

Ecologists have frequently used biochemical assays as proxies for processes or phenomena too difficult to explore by traditional means of investigation. Feathers have been subjected to a number of chemical analyses to study such things as their elemental composition, contaminants, and hormones. The reliance on standard methodology of using concentrations to express quantities of chemical substances is seriously problematic because it creates artifacts by ignoring the physiology of feathers. Some elements and compounds are incorporated into the feather as part of the very building blocks of the keratin. However, others that are less functionally important to feathers (but not necessarily to the bird) enter the developing cells in proportion to their abundance in the bloodstream; in other words, feathers are merely receptacles, and deposition of chemicals is time dependent. In the latter case, one that applies to much of the work done on feather chemistry, data expressed as concentrations are meaningless because the varying mass across the feather alters concentrations in a way that has no biological significance. I discuss this problem and various pitfalls in the chemical analysis of feathers, and offer solutions that ultimately will offer a better understanding of the mechanisms influencing feather composition and, thus, the ecological patterns and processes they were meant to study. © 2010 by the Ecological Society of America. Source


Prasad K.,University of Saskatchewan
International Journal of Angiology | Year: 2012

This review emphasizes the effects of resveratrol on factors involved in the mechanism of atherosclerosis and risk factors for atherosclerosis. The effects of wine and resveratrol on atherosclerosis are also discussed. Resveratrol is a potent antioxidant and an antiinflammatory agent. It reduces the expression of cell adhesion molecules, monocyte colony stimulating factors, matrix metalloproteinases, and growth factors; and inhibits platelet aggregation and vascular smooth muscle cell proliferation. It reduces the serum levels of total cholesterol, triglycerides (TG), and raises high-density lipoprotein cholesterol, inhibits expression of C-reactive protein and lowers the levels of advanced glycation end products and its receptor in the vascular tissue. It lowers the risk factors for plaque rupture. Epidemiological data show that moderate consumption of alcohol has an inverse association with carotid atherosclerosis while high consumption has a positive association with carotid atherosclerosis. Wine reduces the extent of atherosclerosis in animal model. The antiatherosclerotic effect of wine is mainly due to it resveratrol content. Resveratrol reduces the extent of atherosclerosis in animalmodel of atherosclerosis (apolipoprotein [Apo] E-deficient and Apo E≥/≥/low-density lipoprotein receptor-deficient mice and macrophage). In rabbit model of atherosclerosis, both reduction and acceleration of atherosclerosis have been reported with resveratrol. There are no data for regression and slowing of progression of atherosclerosis. Robust clinical trials for suppression of atherosclerosis are lacking. In conclusion, resveratrol has potential but experimental studies in depth and robust clinical trials are lacking for this agent to be of any value in the primary and secondary prevention of coronary and peripheral artery disease. Copyright © 2012 by Thieme Medical Publishers, Inc. Source


Karami E.,University of Saskatchewan | Glisic S.,University of Oulu
IEEE Transactions on Vehicular Technology | Year: 2011

In this paper, we present matrix game-theoretic models for joint routing, network coding, and scheduling problems. First, routing and network coding are modeled by using a new approach based on a compressed topology matrix that takes into account the inherent multicast gain of the network. Scheduling is optimized by a new approach called network graph soft coloring. Soft graph coloring is designed by switching between different components of a wireless network graph, which we refer to as graph fractals, with appropriate usage rates. The network components, which are represented by graph fractals, are a new paradigm in network graph partitioning that enables modeling of the network optimization problem by using the matrix game framework. In the proposed game, which is a nonlinear cubic game, the strategy sets of the players are links, paths, and network components. The outputs of this game model are mixed strategy vectors of the second and third players at equilibrium. The strategy vector of the second player specifies the optimum multipath routing and network coding solution, whereas the mixed strategy vector of the third player indicates the optimum switching rate among different network components or membership probabilities for an optimal soft-scheduling approach. Optimum throughput is the value of the proposed nonlinear cubic game at equilibrium. The proposed nonlinear cubic game is solved by extending a fictitious playing method. Numerical and simulation results prove the superior performance of the proposed techniques compared with the conventional schemes using hard graph coloring. © 2010 IEEE. Source


Kulshreshtha S.N.,University of Saskatchewan
Canadian Journal of Agricultural Economics | Year: 2011

The risks and opportunities presented by climate change in the Prairie Provinces are related to the dry and variable climate-projected temperature increases that are greater than elsewhere in southern Canada; sensitivity of the water resources, ecosystems, and resource economies to seasonal and interannual variations in climate; and to large departures (e.g., drought) from normal conditions. Agriculture industry would face both positive and negative impacts. The net impacts on agriculture are not clear, as various aspects of adaptation are not well understood. Impacts would be felt on other sectors of the economy as well. A warmer climate will present new opportunities for revenue, cost savings, and recreation. Given that some uncertainties exist in our knowledge of impacts and appropriate adaptation measures, more cooperation between scientists and stakeholders would be desirable. Les risques et les avantages que présente le changement climatique dans les provinces des Prairies sont liés au climat sec et variable - augmentations de température prévues plus élevées qu'ailleurs dans le sud du Canada; sensibilité des ressources en eau, des écosystèmes et des économies fondées sur les ressources naturelles aux variations climatiques saisonnières et interannuelles; anomalies importantes (par exemple, la sécheresse) par rapport aux conditions climatiques normales. Le secteur agricole subira des répercussions positives et négatives. Les répercussions nettes sur l'agriculture ne sont pas claires, étant donné que divers aspects de l'adaptation au changement climatique ne sont pas encore bien compris. D'autres secteurs de l'économie subiront également des répercussions. Un climat plus chaud présenterait des avantages sur le plan des revenus, des économies de coûts et des loisirs. Compte tenu de notre manque de certitude concernant les répercussions et les mesures d'adaptation appropriées, une collaboration accrue entre les scientifiques et les parties intéressées serait souhaitable. © 2011 Canadian Agricultural Economics Society. Source


Wangdee W.,BC Hydro | Billinton R.,University of Saskatchewan
IEEE Transactions on Power Systems | Year: 2012

Significant integration of intermittent energy resources such as wind power generation in electric system dictates the need to investigate the system reliability impacts and implications when adding a large amount of intermittent sources. This paper extends the concepts of the effective load carrying capability (ELCC) and the generation replacement capability (GRC) to consider both generation system adequacy and security domains. A system well-being analysis using sequential Monte Carlo simulation was utilized in this paper in order to capture the characteristics in the two reliability standpoints. A deterministic criterion for loss of the largest generating unit was considered in the study as a security measure. An auto-regressive moving average (ARMA) time series model was utilized to simulate hourly wind speeds. The study results were demonstrated using the two test systems designated as the RBTS and IEEE-RTS. © 1969-2012 IEEE. Source


Shahadu H.,University of Saskatchewan
Sustainability Science | Year: 2016

Sustainability research has gained scholarly attention since the 1980s as the new science investigating the changes in social, environmental and economic systems and their impacts on the future of planetary life support systems. Whilst broad literature on sustainability has expanded significantly over the past decades, academic literature developing sustainability as a distinct science has received little attention. After more than two decades of sustainability research, the time has come for us to begin asking reflective questions about what sort of science we call sustainability science. How has the broader research on sustainability contributed to developing sustainability science as a unique discipline within the past two decades? How has the label science promoted or hindered the interdisciplinary project of integrating the natural and social sciences as well as arts and humanities in addressing human nature problems? I argue in this review paper that special efforts need to be made towards the building and positioning of sustainability as an umbrella science for global sustainability research. The benefits of the new sustainability science advocated for in this paper are that; a) it offers a universal definition of sustainability that accounts for both the needs of life and the capacity of planetary life support systems to provide for those needs and b) proposes ways of bridging gaps among different research traditions, facilitating cross disciplinary communication and addressing the challenge of multiple meanings and definitions of concepts facing sustainability research today. © 2016 Springer Japan Source


Butler S.L.,University of Saskatchewan
Physics of the Earth and Planetary Interiors | Year: 2010

A porosity localizing instability occurs in compacting porous media that are subjected to shear if the viscosity of the solid matrix decreases with porosity (Stevenson, 1989). This instability may have significant consequences for melt transport in regions of partial melt in the mantle and may significantly modify the effective viscosity of the asthenosphere (Kohlstedt and Holtzman, 2009). Most analyses of this instability have been carried out assuming an imposed simple shear flow (e.g., Spiegelman, 2003; Katz et al., 2006; Butler, 2009). Pure shear can be realized in laboratory experiments and studying the instability in a pure shear flow allows us to test the generality of some of the results derived for simple shear and the flow pattern for pure shear more easily separates the effects of deformation from rotation. Pure shear flows may approximate flows near the tops of mantle plumes near earth's surface and in magma chambers. In this study, we present linear theory and nonlinear numerical model results for a porosity and strain-rate weakening compacting porous layer subjected to pure shear and we investigate the effects of buoyancy-induced oscillations. The linear theory and numerical model will be shown to be in excellent agreement. We will show that melt bands grow at the same angles to the direction of maximum compression as in simple shear and that buoyancy-induced oscillations do not significantly inhibit the porosity localizing instability. In a pure shear flow, bands parallel to the direction of maximum compression increase exponentially in wavelength with time. However, buoyancy-induced oscillations are shown to inhibit this increase in wavelength. In a simple shear flow, bands increase in wavelength when they are in the orientation for growth of the porosity localizing instability. Because the amplitude spectrum is always dominated by bands in this orientation, band wavelengths increase with time throughout simple shear simulations until the wavelength becomes similar to one compaction length. Once the wavelength becomes similar to one compaction length, the growth of the amplitude of the band slows and shorter wavelength bands that are increasing in amplitude at a greater rate take over. This may provide a mechanism to explain the experimental observation that band spacing is controlled by the compaction length (Kohlstedt and Holtzman, 2009). © 2010 Elsevier B.V. Source


Geyer C.R.,University of Saskatchewan
Epigenetics : official journal of the DNA Methylation Society | Year: 2010

p15(INK4B) and p21(WAF1) are TGF-β targets that are silenced in leukemia by epigenetic mechanisms involving DNA methylation and/or histone modifications. Mechanisms for establishing and maintaining epigenetic silencing of p15(INK4B) and p21(WAF1) are not well established. The reversible nature of epigenetic modifications has lead to the development of drugs that target DNA methyltransferases, histone deacetylases, and histone methyltransferases, which have been used to re-express aberrantly silenced genes in leukemia. Recently, non-coding RNA, referred to as natural antisense transcripts (NATs), have been implicated in the regulation of epigenetic modifications. Here, we review epigenetic mechanisms for silencing p15(INK4B) and p21(WAF1) and the role of NATs in this process. We also review epigenetic drugs and drug combinations used to re-express p15(INK4B) and p21(WAF1). Lastly, we discuss the potential use of NATs to target the activity of epigenetic drugs to specific genes and to permanently re-express epigenetically silenced genes. Source


Kerr W.A.,University of Saskatchewan
Canadian Journal of Agricultural Economics | Year: 2010

The most contentious international trade issues currently arise not from traditional producer requests for protection, but as a result of consumers and other economic agents asking governments to erect trade barriers. The economic model that underpins multilateral trade policy-as manifest in World Trade Organization (WTO) agreements-only predicts that firms will lobby for protection, with no provisions for how governments faced with requests for protection from other groups can respond. Consequently, governments have been forced to defend the imposition of trade barriers using spurious justifications; the WTO dispute mechanism has largely dismissed these justifications, and consumers (and others) feel disenfranchised. The result has been a loss of credibility for the WTO and sometimes its demonization. The WTO needs to change but a new economic model must also be developed to deal with a broader spectrum of protectionist interests. © 2010 Canadian Agricultural Economics Society. Source


Mashkovtsev R.I.,RAS Institute of Geology and Mineralogy | Pan Y.,University of Saskatchewan
Physics and Chemistry of Minerals | Year: 2012

Single-crystal electron paramagnetic resonance (EPR) spectra of fast-electron-irradiated quartz, after annealing at 120 and 200°C, reveal five new E′ type centers, herein labeled E ′ 5, E ′ 6, E ′ 7, E ′ 8 and E ′ 9. Centers E ′ 5, E ′ 7 and E ′ 9 are characterized by the orientations of the unique principal g and A( 29Si) axes close to a short Si-O bond direction, hence representing new variants of the well-established E ′ 1 center. Centers E ′ 6 and E ′ 8 have the orientations of the unique principal g and A( 29Si) axes approximately along a long Si-O bond direction, similar to the E ′ 2 centers. Therefore, these new E′ type centers apparently arise from the removal of different oxygen atoms and represent variable local distortions around the oxygen vacancies. © 2011 Springer-Verlag. Source


Zhang H.,University of Victoria | Shi Y.,University of Victoria | Saadat Mehr A.,University of Saskatchewan
IEEE Transactions on Industrial Electronics | Year: 2011

In this paper, we investigate the problem of robust static output feedback (SOF) control for networked control systems (NCSs) subject to network-induced delays and missing data. The uncertain system matrices are assumed to lie in a convex polytope. The network-induced delays are time varying but within a given interval. The random data missing is characterized by the Bernoulli random binary distribution. Delay-dependent conditions for the exponential mean-square stability are first established in terms of matrix inequalities. Then, for the robust stabilization problem, the design of an SOF controller is presented by solving bilinear matrix inequalities (BMIs). In order to efficiently solve a nonconvex BMI, we propose an approach based on the linear matrix inequality technique. Furthermore, the developed approach is employed to design the remote proportional-integral-derivative (PID) controller for NCSs. The design of a digital PID controller is formulated as a synthesis problem of the SOF control via an augmentation method. Simulation examples illustrate the effectiveness of the proposed methods. © 2011 IEEE. Source


Larson K.P.,University of Saskatchewan
Geosphere | Year: 2012

The Tama Kosi/Rolwaling area of eastcentral Nepal is underlain by the exhumed mid-crustal core of the Himalaya. The geology of the area consists of Greater Himalayan sequence phyllitic schist, paragneiss, and orthogneiss that generally increase in metamorphic grade from biotite ± garnet assemblages to sillimanite-grade migmatite up structural section. All metamorphic rocks are pervasively deformed and commonly record top-to-the-south sense shear. The top of the Greater Himalayan sequence in the mapped area is marked by an undeformed, pegmatitic leucogranite stock. Relationships in adjacent areas constrain the age of the leucogranite and the deformation structures it crosscuts, including the top-to-thesouth sense deformation, to be older than middle Miocene. The lower portion of the exhumed midcrustal package has been subject to late-stage folding during the formation of the Tama Kosi window, a structural culmination that may refl ect out-of-sequence adjustment of the orogenic wedge. The geology of the mapped area appears similar to that observed in the adjacent, better-studied Everest region. © 2012 Geological Society of America. Source


Mani S.,Lakehead University | Li H.,Lakehead University | Untereiner A.,Thunder Bay Regional Research Institute | Wu L.,Thunder Bay Regional Research Institute | And 6 more authors.
Circulation | Year: 2013

Background-Cystathionine γ-lyase (CSE) produces hydrogen sulfide (H2S) in the cardiovascular system. The deficiency of CSE in mice leads to a decreased endogenous H2S level, an age-dependent increase in blood pressure, and impaired endothelium-dependent vasorelaxation. To date, there is no direct evidence for a causative role of altered metabolism of endogenous H2S in atherosclerosis development. Methods and Results-Six-week-old CSE gene knockout and wild-type mice were fed with either a control chow or atherogenic paigen-type diet for 12 weeks. Plasma lipid profile and homocysteine levels, blood pressure, oxidative stress, atherosclerotic lesion size in the aortic roots, cell proliferation, and adhesion molecule expression were then analyzed. CSE-knockout mice fed with atherogenic diet developed early fatty streak lesions in the aortic root, elevated plasma levels of cholesterol and low-density lipoprotein cholesterol, hyperhomocysteinemia, increased lesional oxidative stress and adhesion molecule expression, and enhanced aortic intimal proliferation. Treatment of CSE-knockout mice with NaHS, but not N-acetylcysteine or ezetimibe, inhibited the accelerated atherosclerosis development. Double knockout of CSE and apolipoprotein E gene expression in mice exacerbated atherosclerosis development more than that in the mice with only apolipoprotein E or CSE knockout. Conclusions-Endogenously synthesized H2S protects vascular tissues from atherogenic damage by reducing vessel intimal proliferation and inhibiting adhesion molecule expression. Decreased endogenous H2S production predisposes the animals to vascular remodeling and early development of atherosclerosis. The CSE/H2S pathway is an important therapeutic target for protection against atherosclerosis. © 2013 American Heart Association, Inc. Source


Kerrich R.,University of Saskatchewan | Manikyamba C.,National Geophysical Research Institute
Canadian Journal of Earth Sciences | Year: 2012

An association of Nb-enriched basalts (NEB), high-MgO andesites (HMA), and flows with adakitic characteristics are interlayered with tholeiitic pillow basalts in the 2.7 Ga Penakacherla greenstone belt of are present, a high-Mg# Ni (0.65-0.56, 106-52 ppm) and low-Mg# Ni (0.45-0.34, 32-13 ppm) counterpart; Nb spans 6.3-18 ppm relative to "normal" arc tholeiitic basalts, where Nb ~ 3 ppm, and hence qualify as NEB. Basalts plot on the low-Ce/Yb trend of intraoceanic arcs, and have fractionated heavy rare-earth elements (HREE) indicative of melting with residual garnet at >90 km. Ratios of Nb/Ta (7.6 ± 0.7), Zr/Hf (44 ± 0.8), and Zr/Sm (27 ± 2.4) are systematically low, high, and similar to respective primitive mantle ratios of 17, 36, and 25, consistent with a mid-ocean ridge basaltlike mantle source in the sub-arc mantle wedge. Intermediate compositions are divided into high-K but low-Na (K 2O 1.8- 5.3; Na 2O 0.5-2.1 wt.%) and low-K but high-Na (K 2O 0.10-1.5; Na 2O 4.1-5.6 wt.%) populations defining distinct magma series; accordingly, these are termed K-adakitic and Na-adakitic rocks, respectively. The Na-type has SiO 2≥56 wt.%, MgO<3 wt.%, Mg# ~0.5, Na 2O ≥3.5 wt.%, K 2O ≤3 wt.%, Yb ≤1.9 ppm, Cr ≥30 ppm, with slightly lower limits of Al 2O 3≥15 wt.% and La/Yb 7.5-8.2 versus ≥20, thus conforming to most criteria for Na-adakites. NEB are interpreted as melts of mantle wedge hybridized by adakitic melts having residual garnet; and Na-adakites are slab melts of low-Mg basalt in the garnet-amphibolite facies. K-adakitic flows are melts of mafic lower crust, or melts of lower crust delaminated into mantle wedge asthenosphere. Source


Prasad K.,University of Saskatchewan
Molecular and Cellular Biochemistry | Year: 2010

It is not known if vitamin E in hyperlipidemia and hypercholesterolemia of longer duration has any beneficial or adverse effects on electrolytes, and liver and kidney function. The objectives of this study are to determine (i) if long duration of mild hypercholesterolemia has any adverse effects on serum electrolytes, glucose and enzymes related to liver and kidney functions; (ii) if vitamin E has any effects on serum electrolytes, glucose and enzymes related to liver and kidney function in hypercholesterolemia. Blood samples were collected from the rabbits before and at various intervals during administration of a high cholesterol diet (0.25%) for 2 and 4 months, and while on a high cholesterol diet with vitamin E following a high cholesterol diet. Measurements of serum total cholesterol (TC), glucose, aspartate aminotransferase (AST), alkaline phosphatase (ALP), alanine aminotransferase (ALT), gamma- glutamyltransferase (GGT), albumin, creatinine, electrolytes [sodium (Na), potassium (K), chloride (Cl), and carbon dioxide (CO2)] were made. High cholesterol diet for 2 months produced hypercholesterolemia which was associated with reductions in serum glucose, unaltered serum electrolytes, ALT, ALP, GGT, albumin and creatinine, and increased levels of AST. Hypercholesterolemia for 4 months had effects similar to hypercholesterolemia for 2 months except it lowered serum ALP. Vitamin E did not affect any of the parameters except serum glucose and Cl, which decreased compared to the values at month 2. Hypercholesterolemia for short and long term does not have adverse effects on liver or kidney function, and serum electrolytes. Vitamin E during hypercholesterolemia does not affect serum electrolytes or liver and kidney function. © 2009 Springer Science+Business Media, LLC. Source


Summerfield A.,Institute of Virology and Immunology | Meurens F.,University of Saskatchewan | Ricklin M.E.,Institute of Virology and Immunology
Molecular Immunology | Year: 2015

The porcine skin has striking similarities to the human skin in terms of general structure, thickness, hair follicle content, pigmentation, collagen and lipid composition. This has been the basis for numerous studies using the pig as a model for wound healing, transdermal delivery, dermal toxicology, radiation and UVB effects. Considering that the skin also represents an immune organ of utmost importance for health, immune cells present in the skin of the pig will be reviewed. The focus of this review is on dendritic cells, which play a central role in the skin immune system as they serve as sentinels in the skin, which offers a large surface area exposed to the environment. Based on a literature review and original data we propose a classification of porcine dendritic cell subsets in the skin corresponding to the subsets described in the human skin. The equivalent of the human CD141+ DC subset is CD1a-CD4-CD172a-CADM1high, that of the CD1c+ subset is CD1a+CD4-CD172a+CADM1+/low, and porcine plasmacytoid dendritic cells are CD1a-CD4+CD172a+CADM1-. CD209 and CD14 could represent markers of inflammatory monocyte-derived cells, either dendritic cells or macrophages. Future studies for example using transriptomic analysis of sorted populations are required to confirm the identity of these cells. © 2014 The Authors. Source


Ferrari M.C.O.,WCVM | McCormick M.I.,James Cook University | Munday P.L.,James Cook University | Meekan M.G.,Australian Institute of Marine Science | And 3 more authors.
Ecology Letters | Year: 2011

Little is known about the impact of ocean acidification on predator-prey dynamics. Herein, we examined the effect of carbon dioxide (CO 2) on both prey and predator by letting one predatory reef fish interact for 24h with eight small or large juvenile damselfishes from four congeneric species. Both prey and predator were exposed to control or elevated levels of CO 2. Mortality rate and predator selectivity were compared across CO 2 treatments, prey size and species. Small juveniles of all species sustained greater mortality at high CO 2 levels, while large recruits were not affected. For large prey, the pattern of prey selectivity by predators was reversed under elevated CO 2. Our results demonstrate both quantitative and qualitative consumptive effects of CO 2 on small and larger damselfish recruits respectively, resulting from CO 2-induced behavioural changes likely mediated by impaired neurological function. This study highlights the complexity of predicting the effects of climate change on coral reef ecosystems. © 2011 Blackwell Publishing Ltd/CNRS. Source


Wyman D.A.,University of Sydney | Kerrich R.,University of Saskatchewan
Australian Journal of Earth Sciences | Year: 2012

New geochemical and isotopic data for volcanic and shallow-level intrusive rocks of the Murchison Domain in the Youanmi Terrane of the Yilgarn Craton help to clarify some of the stratigraphic ambiguities in the area and are consistent with the most recent lithostratigraphic model. The results reveal the presence of previously unrecognised examples of the boninite-depleted tholeiite suite that, based on εNd T > 4, were likely derived from refractory mantle following plume melting. These new findings support the conclusions of previous studies that magmatism in Archean volcanic successions, including mantle plume-associated and arc sequences, display geochemical evidence of refractory plume-related magma sources throughout their development. The presence of well-preserved boninites in the Polelle Group indicates a significant role for subduction tectonics during the 2825-2700 Ma evolution of the Youanmi Terrane. The subduction zone is tentatively linked to the accretionary processes proposed along the Youanmi Terrane-Narryer Terrane boundary. This model also implies that in the eastern Yilgarn Craton, the initial phases of craton re-assembly may have been driven by this subduction zone prior to the development of an arc off the eastern edge of the craton at ca 2715 Ma. © 2012 Copyright Taylor and Francis Group, LLC. Source


Manikyamba C.,National Geophysical Research Institute | Kerrich R.,University of Saskatchewan
Geoscience Frontiers | Year: 2012

Greenstone belts of the eastern Dharwar Craton, India are reinterpreted as composite tectonostratigraphic terranes of accreted plume-derived and convergent margin-derived magmatic sequences based on new high-precision elemental data. The former are dominated by a komatiite plus Mg-tholeiitic basalt volcanic association, with deep water siliciclastic and banded iron formation (BIF) sedimentary rocks. Plumes melted at <90 km under thin rifted continental lithosphere to preserve intraoceanic and continental margin aspects. Associated alkaline basalts record subduction-recycling of Mesoarchean oceanic crust, incubated in the asthenosphere, and erupted coevally with Mg basalts from a heterogeneous mantle plume. Together, komatiites-Mg basalts-alkaline basalts plot along the Phanerozoic mantle array in Th/Yb versus Nb/Yb coordinate space, representing zoned plumes, establishing that these reservoirs were present in the Neoarchean mantle. Convergent margin magmatic associations are dominated by tholeiitic to calc-alkaline basalts compositionally similar to recent intraoceanic arcs. As well, boninitic flows sourced in extremely depleted mantle are present, and the association of arc basalts with Mg-andesites-Nb enriched basalts-adakites documented from Cenozoic arcs characterized by subduction of young (<20 Ma), hot, oceanic lithosphere. Consequently, Cenozoic style "hot" subduction was operating in the Neoarchean. These diverse volcanic associations were assembled to give composite terranes in a subduction-accretion orogen at ∼2.7 Ga, coevally with a global accretionary orogen at ∼2.7 Ga, and associated orogenic gold mineralization. Archean lithospheric mantle, distinctive in being thick, refractory, and buoyant, formed complementary to the accreted plume and convergent margin terranes, as migrating arcs captured thick plume-plateaus, and the refractory, low density, residue of plume melting coupled with accreted imbricated plume-arc crust. © 2011, China University of Geosciences (Beijing) and Peking University. Production and hosting by Elsevier B.V. All rights reserved. Source


Kerrich R.,University of Saskatchewan | Said N.,University of Western Australia | Manikyamba C.,National Geophysical Research Institute | Wyman D.,University of Sydney
Gondwana Research | Year: 2013

Hydrothermally altered Archean igneous suites erupted in the submarine environment record variable excursions of Ce/Ce* and Th/U from primary magmatic values of 1 and ~. 4 respectively. Rhyolites of the 2.96. Ga bimodal basalt-rhyolite sequence of the Murchison Domain, Yilgarn Craton, Western Australia, hosting the Golden Grove VMS deposit, are enriched in MnO up to ten fold over primary values. Th/U ratios span 2.6-4.7, Ce/Ce* = 2.5-16, and Eu/Eu* = 1.3-3. The 2.8. Ga Lady Alma ultramafic-mafic subvolcanic complex of the same domain features highly dispersed MREE and LREE due to intense hydrothermal alteration. Th/U ratios span 0.005-0.16 from preferential addition of U, with Ce/Ce* = 0.6-2.2, and Eu/Eu* = 1-1.4. The eastern Dharwar Craton, India, includes greenstone terranes dominantly 2.7-2.6. Ga. Adakites of the Gadwal terrane preserve near primary magmatic Th/U, Ce/Ce*, and Eu/Eu*. In contrast, igneous lithologies of the Hutti greenstone terrane are characterized by total ranges of Th/U = 2-5.8, Ce/Ce* = 1.01-1.28, and Eu/Eu* = 0.82-1.26, and counterparts of the Sandur terrane have Th/U = 0.4-6.0, Ce/Ce* = 0.9-1.25, and Eu/Eu* = 0.8-1.8. Coexistence of Ce and Eu anomalies may reflect a two-stage process: low-temperature hydrothermal alteration at high water-rock ratios by oxidizing fluids, with evolution of the hydrothermal systems to high temperature, low water-rock ratios, under reducing conditions. Uranium is dominantly added to these lithologies over Th in common with Recent altered ocean crust. Iron-rich shales in the Sandur terrane record U-enrichment where Th/U = 2-4. Three shales record true negative Ce anomalies and Eu/Eu* = 0.8-2.4: true negative Ce anomalies, present in some other Archean iron formations, are interpreted as a signature of precipitates from the ocean water column whereas Eu anomalies are hydrothermal in origin. Volcanic flows of the 2.7. Ga Blake River Group, Abitibi greenstone terrane, Canada, preserve Th/U = 1.5-8.5, the conjunction of low Th/U values with Ce/Ce* = 1.4 in two samples, and Eu/Eu* = 0.15-1.3. Mobility of U and Ce in these hydrothermally altered Archean lithologies is in common with their mobility in Phanerozoic counterparts by oxygenated fluids. © 2012 International Association for Gondwana Research. Source


Tse J.S.,University of Saskatchewan | Klug D.D.,NRC Steacie Institute for Molecular Sciences
Physical Chemistry Chemical Physics | Year: 2012

We offer our viewpoint on the nature of amorphous ices produced by pressurization of crystalline ice Ih and the inter-relationship between them from an atomistic perspective. We argue that the transformation of high density amorphous (HDA) ice from crystalline ice is due to a mechanical process arising from the instability of the ice Ih structure. The densification of HDA upon thermal annealing under pressure is a relaxation process. The conversion of the densified amorphous ice to a lower density form (LDA) upon the release of pressure can be attributed to a similar process. It is speculated that amorphous ices are metastable frustrated structures due to the large activation barriers associated with proton reorientation in the formation of the underlying stable crystalline ice polymorphs. © 2012 the Owner Societies. Source


Paikaray S.,University of Saskatchewan
Reviews in Environmental Science and Biotechnology | Year: 2012

Black shales are high organic matter-rich dark coloured mudstones those are often deposited during 'oceanic anoxia events'. Most of the black shale horizons are rich in arsenic far above their average crustal abundance and are susceptible to weathering eventually leaching high As contents to the surrounding environment causing As enrichment in soil and water which adversely affect the living beings. Numerous arsenic contaminations are being reported from black shale hosted areas globally, hence, making extremely crucial to understand the processes of enrichment, leaching and broader prospective of environmental hazards. Few studies have shown arsenic concentrations as high as 6,000 mg/kg within black shales causing groundwater enrichment up to hundreds mg/L. Arsenic is commonly attached to sulphide mineral structure and partly to organic matter and clay contents during deposition and diagenetic processes. Majority of sulphide bound arsenic becomes available to oxidative dissolution processes in presence of atmospheric oxygen and water which is further triggered by certain microbial community such as Acidophilus ferrooxidans hence, enhancing arsenic release. Physical weathering processes carry the arsenic-rich shale constituents to the depositional site where it is dissolved subsequently. Chemical diffusion and mechanical transport are two prime processes transporting arsenic from black shale horizons to the water bodies or soil columns, while air pollutions are caused by combustions of organic matter-rich coaly shales. © 2012 Springer Science+Business Media B.V. Source


The traditional winter wheat (Triticum aestivum L.) production area on the North American Great Plains extended as far north as southern Alberta, Canada. This paper reviews a research and development program initiated with the objective of expanding production north and east into higher winter stress areas of the Canadian prairies. Winter survival was considered the main limitation to production in this region. However, the widespread adoption of no-till seeding into standing stubble for snow trapping has proven to be a successful method of overwintering wheat if cold hardy cultivars are grown using recommended management practices. Plant breeding improvements have increased production potential and winter wheat has become western Canada's third largest wheat class. Average commercial yields of 149, 125, and 118% of spring wheat in Manitoba, Saskatchewan, and Alberta, respectively, have demonstrated the high yield potential that can be realized while employing environmentally sustainable crop management practices. In light of current environmental concerns, changing weather patterns, diminishing world wheat reserves, and an ever increasing global population to feed, one would assume that winter wheat production in western Canada would be widely embraced. However, marketing obstacles and diffi culties inserting winter wheat into rotations, both of which have a direct infl uence on farmers' net returns, remain to be overcome for this potential to be fully realized. © Crop Science Society of America. Source


Beaton N.R.,University of Saskatchewan
Journal of Physics A: Mathematical and Theoretical | Year: 2015

Self-avoiding walks (SAWs) are a simple and well-known model of long, flexible polymers in a good solvent. Polymers being pulled away from a surface by an external agent can be modelled with SAWs in a half-space, with a Boltzmann weight = y e f associated with the pulling force. This model is known to have a critical point at a certain value yc of this Boltzmann weight, which is the location of a transition between the so-called free and ballistic phases. The value yc = 1 has been conjectured by several authors using numerical estimates. We provide a relatively simple proof of this result, and show that further properties of the free energy of this system can be determined by re-interpreting existing results about the two-point function of SAWs. © 2015. The American Astronomical Society. All rights reserved. Source


Fang J.,University of Saskatchewan
Nutrition | Year: 2015

Anthocyanins are a group of water-soluble pigments that confer the blue, purple, and red color to many fruits. Anthocyanin-rich fruits can be divided into three groups based on the types of aglycones of their anthocyanins: pelargonidin group, cyanidin/peonidin group, and multiple anthocyanidins group. Some fruits contain a major anthocyanin type and can serve as useful research tools. Cyanidin glycosides and peonidin glycosides can be metabolically converted to each other by methylation and demethylation. Both cyanidin and peonidin glycosides can be metabolized to protocatechuic acid and vanillic acid. Pelargonidin-3-glucoside is metabolized to 4-hydroxybenoic acid. On the other hand, phenolic acid metabolites of delphinidin, malvidin, and petunidin glycosides are unstable and can be further fragmented into smaller molecules. A literature review indicates berries with higher cyanidin content, such as black raspberries, chokeberries, and bilberries are more likely to produce an antiinflammatory effect. This observation seems to be consistent with the hypothesis that one or more stable phenolic acid metabolites contribute to the antiinflammatory effects of anthocyanin-rich fruits. More studies are needed before we can conclude that fruits rich in cyanidin, peonidin, or pelargonidin glycosides have better antiinflammatory effects. Additionally, fruit polyphenols other than anthocyanins could contribute to their antiinflammatory effects. Furthermore, blueberries could exert their health effects with other mechanisms such as improving intestinal microbiota composition. In summary, this classification system can facilitate our understanding of the absorption and metabolic processes of anthocyanins and the health effects of different fruits. © 2015 Published by Elsevier Inc. Source


Dehghanian P.,Sharif University of Technology | Fotuhi-Firuzabad M.,Sharif University of Technology | Aminifar F.,Sharif University of Technology | Billinton R.,University of Saskatchewan
IEEE Transactions on Power Delivery | Year: 2013

Although reliability-centered maintenance (RCM) has proven its noticeable merits in many industries, has not been yet furnished with efficient analytical methods in the power engineering context. The first of this two-paper set presents a practical framework by which the RCM procedure can be implemented in power distribution systems. The proposed algorithm consists of three main stages. The prerequisites of the analysis are outlined in the first stage. In the second stage, an approach is developed to identify the network's critical components, from the reliability point of view. Having practically modeled the components' failure rates, an efficient cost/benefit evaluation approach is then proposed to distinguish a variety of maintenance plans. The optimal set of maintenance strategies is next adopted for implementation. The algorithm is terminated in the third stage by recording both technical and economical outcomes for tuning the forward maintenance activities. The proposed methodology, although tailored to distribution networks, is generic enough to be applied to other power system areas. In the companion paper, the proposed methodology is examined by application to the Birka distribution system of Stockholm City, Sweden, and more practical aspects are discussed. © 1986-2012 IEEE. Source


Logan D.C.,University of Saskatchewan
Biochemical Society Transactions | Year: 2010

Mitochondria are involved in many fundamental processes underpinning plant growth, development and death. Owing to their multiple roles, as the sites of the tricarboxylic acid cycle and oxidative phosphorylation, as harbourers of their own genomes and as sensors of cell redox status, amongst others, mitochondria are in a unique position to act as sentinels of cell physiology. The plant chondriome is typically organized as a population of physically discrete organelles, but visualization of mitochondria in living tissues has shown that the mitochondrial population is highly interactive. Mitochondria are highly motile and movement on the cytoskeleton ensures that the physically discrete organelles come into contact with one another, which allows transient fusion, followed by division of the mitochondrial membranes. This article serves to review our current knowledge of mitochondrial fusion and division, and link this to recent discoveries regarding a putative mitochondrial 'health-check' and repair process, whereby non-repairable dysfunctional mitochondria can be removed from the chondriome. It is proposed that the unequal distribution of the multipartite plant mitochondrial genome between discrete organelles provides the driver for transient mitochondrial fusion that, in turn, is dependent on mitochondrial motility, and that both fusion and motility are necessary to maintain a healthy functional chondriome. ©The Authors. Source


Engler-Stringer R.,University of Saskatchewan
Health Education and Behavior | Year: 2010

Over the course of the past century, the quantity of prepackaged, pre-prepared foods available in the North American context has increased dramatically. This study examines the shifts in food practices that are taking place through an exploration of the day-to-day cooking practices of a group of young, low-income women in Montreal and considers how these contribute to health problems such as obesity and nutritional deficiencies in addition to health inequalities within populations. The participatory study uses data from five focus groups with a total of 22 participants to contribute to our understanding of how social and physical food environments (the "foodscape") shape daily food and cooking practices. Aspects of these environments that were discussed include household roles and responsibilities that require complex management, personal food choice and skill, as well as health, learning, and access to food. © 2010 by SOPHE. Source


Although biologists and veterinarians have shown considerable success in working together to address wildlife-related issues, including disease, chemical immobilization, reproductive biology, and conservation biology, examples of shared efforts to evaluate and ensure the welfare of study animals are mostly absent. I present the case that this deficiency arises primarily from a lack of mutual understanding between fields with respect to the other's training and experience in addressing animal welfare issues. In effect, each assumes that the final word on animal welfare rests with the other. The reality is, however, that neither field contains the knowledge and skills required to address animal welfare concerns alone. Nevertheless, wildlife researchers are increasingly encountering difficulties conducting research on wild animals because of opposition from stakeholders on the basis of animal welfare concerns. Further, a growing number of articles in the peer-reviewed scientific literature are reporting on potential biases in research results developing from the welfare impacts of widely used techniques, including methods of capturing and marking wildlife. By viewing animal welfare as a shared responsibility and combining their knowledge and skills, wildlife biologists and veterinarians have an opportunity to reform "invasive" wildlife research in a manner that is less harmful to the animals being studied, less likely to bias research results, and less objectionable to the stakeholders who ultimately influence or make decisions on how wildlife research is conducted. © The Author 2013. Source


Morozov I.B.,University of Saskatchewan
Journal of Seismology | Year: 2013

Multi-phase long-period t* measurements are among the key evidences for the frequency-dependent mantle attenuation factor, Q. However, similarly to Q, poorly constrained variations of Earth's structure may cause spurious frequency-dependent effects in the observed t*. By using an attenuation-coefficient approach which incorporates measurements of geometric spreading (GS), such effects can be isolated and removed. The results show that the well-known increase of body P-wave t* from ~0. 2 s at short periods to ~1-2 s at long periods may be caused by a small and positive bias in the underlying GS, which is measured by a dimensionless parameter γ* ≈ 0. 06. Similarly to the nearly constant t* at teleseismic distances, this GS bias is practically range-independent and interpreted as caused by velocity heterogeneity within the crust and uppermost mantle. This bias is accumulated within a relatively thin upper part of the lithosphere and may be closely related to the crustal body-wave GS parameter γ ~ 4-60 mHz reported earlier. After a correction for γ, P-wave tP* becomes equal ~0. 18 s at all frequencies. By using conventional dispersion relations, this value also accounts for ~40 % of the dispersion-related delay in long-period travel times. For inner-core attenuation, the attenuation coefficient shows a distinctly different increase with frequency, which is remarkably similar to that of fluid-saturated porous rock. As a general conclusion, after the GS is accounted for, no absorption-band type or frequency-dependent upper-mantle Q is required for explaining the available t* and velocity dispersion observations. The meaning of this Q is also clarified as the frequency-dependent part of the attenuation coefficient. At the same time, physically justified theories of elastic-wave attenuation within the Earth are still needed. These conclusions agree with recent re-interpretations of several surface, body and coda-wave attenuation datasets within a broad range of frequencies. © 2012 Springer Science+Business Media B.V. Source


Pehrsson S.J.,Geological Survey of Canada | Berman R.G.,Geological Survey of Canada | Eglington B.,University of Saskatchewan | Rainbird R.,Geological Survey of Canada
Precambrian Research | Year: 2013

A variety of early Paleoproterozoic supercontinents or supercratons have been proposed, including Kenorland, Superia and Vaalbara. Improved geologic knowledge of the Churchill Province, Canadian shield, suggests that the classical Kenorland configuration, with linked Rae and Hearne cratons, is invalid and represents a younger ca. 1.9. Ga Nuna configuration. We review the early Paleoproterozoic tectonic history of the Rae craton and propose that the ca. 2.55-2.50. Ga MacQuoid and 2.50-2.28. Ga Arrowsmith orogens represent critical piercing points for supercontinent reconstruction. Utilizing the StratDB and DateView databases, we have identified nearly two dozen regions worldwide that show effects of these orogenic events, including the Rae, Gawler-Mawson, peninsular India, West Africa, Amazonia, North China, and Sask crustal blocks. We propose that these cratonic blocks form a distinct Rae family lineage. Utilizing new time-space plots for the Rae family and components of the Superia and Vaalbara supercratons, we demonstrate that the Rae family lacks the distinctive early Paleoproterozoic depositional and glaciogenic record characteristic of Superia and Vaalbara, but has an important contemporaneous record of juvenile crust formation and contractional orogenesis. We propose the collective history of the Rae family is best reconciled if it represents the now dispersed blocks of a third earliest Paleoproterozoic supercraton that we term Nunavutia. In this model the magmatic and tectonometamorphic record of these cratons includes an early 2.55-2.45. Ga period of interior collisional orogenesis in which the supercraton amalgamated, and a later phase of long-lived peripheral orogenesis (2.45-2.28. Ga) prior to its partial break-up at ca. 2.05. Ga. Forming within an otherwise globally quiescent period, the history of the Rae family is important for assessment of constrasting models of early Paleoproterozoic geodynamic activity. © 2013. Source


Smith L.W.,University of Saskatchewan
Journal of Medical Humanities | Year: 2010

In the modern world, technology has enabled us to understand the connections between the menstrual cycle and female fertility and to observe the reproductive process even from conception. Unable to see inside the living body, however, eighteenth-century people imagined reproduction and fertility holistically. Their understanding of fertility was inseparable from the way in which they imagined the inner-workings of the humoral body. Although menstruation was understood to be connected to reproduction, it was considered unreliable, a peripheral indicator of fertility. Above all, the best marker of a woman's fecundity was good overall health. © Springer Science+Business Media, LLC 2009. Source


Szpunar B.,University of Saskatchewan
Journal of Physics and Chemistry of Solids | Year: 2012

The local-spin-density approximation plus Hubbard U (commonly called LDAU) is used in a comprehensive study of the structural, mechanical and optical properties of urania. It is shown that using the new LDAU implementation in CASTEP calculations, the symmetry constraints, imposed in agreement with both the symmetry of the unit cell and the present magnetic interaction, can be used to predict the ground state with the occupancy of the orbitals (5f in urania) in agreement with Hund's rules. The inclusion of a Hubbard U correction to 5f electrons of uranium changes urania from a metal to an insulator and, therefore, has a dramatic effect on the localisation of the electron spin and charge density on uranium. The value of the adjustable parameter U, which predicts the optical band gap in agreement with the experiment, leads to a slightly larger lattice constant than experimentally observed. The real and imaginary dielectric constants, reflectivity and energy loss functions are calculated using independent particle excitation approximations. The 5f intraband transitions are described adequately by the LDA and the effective U parameter, which is equal to 3.5 eV. However, additional corrections are needed to account for the 1-eV shift in the 2p-6d transitions. © 2012 Elsevier Ltd. Source


Zhang L.,University of Saskatchewan
World Patent Information | Year: 2011

This study attempts to identify the areas of technological strength of the province of Saskatchewan, Canada, whose economy is heavily based on natural resources, by analyzing patent information. 606 US patents held by Saskatchewan organizations were identified. The results show that inventive activities are steadily growing and Saskatchewan's technological development has experienced three stages. The Initial stage (1971-1985) was dominated by traditional resource-based technologies; the Emerging stage (1986-1995) was characterized by the emergence of new technologies in the Drugs & Medical field; and the Developing stage (1996-2009) was marked by more of a balance between traditional and new technologies. In Canada and worldwide, inventive activities in Computers & Communication field have been most prominent since the last decade. However, Saskatchewan demonstrates a different path from the rest of the world. While traditional technological fields still dominate in the province, it is gradually building its strength in the Drugs & Medical field. The results present a possibility to diversify the provincial economy if policy makers develop strategies to facilitate the transfer of new technologies to industries. © 2011 Elsevier Ltd. Source


Jilani K.,University of Tubingen | Qadri S.M.,University of Tubingen | Qadri S.M.,University of Saskatchewan | Lang F.,University of Tubingen
Cellular Physiology and Biochemistry | Year: 2013

Background/aims: Geldanamycin, a benzoquinone ansamycin antibiotic, and its analogues induce apoptosis of tumor cells and are thus considered for the treatment of cancer. Similar to apoptosis of nucleated cells, erythrocytes may enter eryptosis, the suicidal erythrocyte death characterized by cell shrinkage and by cell membrane scrambling with phosphatidylserine-exposure at the erythrocyte surface. Triggers of eryptosis include increase of cytosolic Ca 2+-concentration ([Ca2+]i) and formation of ceramide. The present study explored, whether geldanamycin modifies [Ca 2+]i, ceramide formation, cell volume and phosphatidylserine abundance at the erythrocyte surface. Methods: Erythrocyte volume was estimated from forward scatter, phosphatidylserine-abundance from annexin V binding, hemolysis from hemoglobin release, ceramide formation from binding of fluorescent antibodies and [Ca2+]i from Fluo3-fluorescence. Results: A 48 hours exposure to geldanamycin significantly decreased forward scatter (≥ 5 μM), significantly increased annexin-V-binding (≥ 25 μM), but did not significantly modify Fluo3-fluorescence (up to 50 μM). The annexin-V-binding following geldanamycin treatment was not significantly modified by removal of extracellular Ca2+ but was paralleled by significantly increased ceramide formation (50 μM). Conclusions: Geldanamycin stinulated eryptosis, an effect at least partially due to ceramide formation. © 2013 S. Karger AG, Basel. Source


Ghezelbash A.M.,University of Saskatchewan
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2015

We construct new classes of exact cosmological solutions to five-dimensional Einstein-Maxwell-dilaton theory with two coupling constants for the dilaton-Maxwell term and the dilaton-cosmological constant term. All the solutions are nonstationary, and the solutions where both coupling constants are nonzero are almost regular everywhere. The size of the spatial section of the asymptotic metric shrinks to zero at early times and increases to infinitely large at very late times. The cosmological constant depends on the dilaton coupling constant and can take positive, zero, or negative values. © 2015 American Physical Society. Source


Lajevardi S.A.,Tarbiat Modares University | Shahrabi T.,Tarbiat Modares University | Szpunar J.A.,University of Saskatchewan
Applied Surface Science | Year: 2013

The main goal of this research is the synthesis of functionally graded nickel-nano Al2O3 composite coatings by using pulse deposition in which the amount of the embedded nano alumina particles changes in the cross section of the composite. For producing functionally graded nanocomposite coatings by pulse electrodeposition under ultrasonic agitation, frequency and duty cycle changes can be applied and in this research, the influence of both parameters has been studied. Microstructure of these coatings investigated by SEM, EBSD and XRD methods. By changing the duty cycle from 90% to 10% at different frequency, the microstructure of the coatings did not change significantly. These coatings showed ductile structure with {0 0 1} texture at primary layers and small randomly oriented grains at final layers. The most important factor affecting the microstructure of the nickel matrix was the average current density and incorporation of nano alumina particles does not have significant effect on the microstructure. The optimum condition for production of functionally graded nano Al2O3-Ni coating was changing of the duty cycle from 90% to 10% at fixed frequency of 10 Hz. © 2013 Published by Elsevier B.V. Source


Neudorf C.,University of Saskatchewan
Healthcare Management Forum | Year: 2012

Most regional health authorities include "improving population health and health equity" in their mission, vision, or priority statements, yet few regional health authorities or hospitals have been shown to devote the sufficient time and resources to make significant progress toward this aim. Health system leaders want to act on this priority, but many barriers and challenges conspire to limit their effectiveness. Improving population health requires both population-based and individual-level initiatives aimed at preventing disease and improving health equity. Practical examples for integrating a population health approach into the health system are presented for healthcare leaders. © 2012 Canadian College of Health Leaders. Source


Gurao N.P.,University of Saskatchewan | Sethuraman S.,Cummins Inc. | Suwas S.,Indian Institute of Science
Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science | Year: 2013

The evolution of microstructure and texture in commercially pure titanium has been studied as a function of strain path during rolling using experimental techniques and viscoplastic self-consistent simulations. Four different strain paths, namely unidirectional rolling, two-step cross rolling, multistep cross rolling, and reverse rolling, have been employed to decipher the effect of strain path change on the evolution of deformation texture and microstructure. The cross-rolled samples show higher hardness with lower microstrain and intragranular misorientation compared to the unidirectional rolled sample as determined from X-ray diffraction and electron backscatter diffraction, respectively. The higher hardness of the cross-rolled samples is attributed to orientation hardening due to the near basal texture. Viscoplastic self-consistent simulations are able to successfully predict the texture evolution of the differently rolled samples. Simulation results indicate the higher contribution of basal slip in the formation of near basal texture and as well as lower intragranular misorientation in the cross-rolled samples. © 2012 The Minerals, Metals & Materials Society and ASM International. Source


Sari N.,University of Saskatchewan
Canadian Journal of Public Health | Year: 2010

Objectives: To estimate the impact of increased physical activity on utilization of hospital services among older adults in Canada. Methods: The paper uses the Canadian Community Health Survey Cycle 2.1, and count data regression models. The study sample includes 18,196 adults aged 65 and above. Specification tests are used in order to identify the appropriate count data model, and sensitivity analyses are conducted to check the robustness of the results. Results: The paper shows that physical activity is negatively associated with the probability of staying in the hospital as well as the numbers of hospital stay among users. However, the potential gain decreases as current activity level increases. The results also imply that an additional 20-minute daily walk by inactive older Canadians would decrease total hospital stays by about 2% of the total annual inpatient days. This is equivalent to 1.2% of total hospital bed capacity in a given year. Conclusions: Health promotion efforts to increase the level of activity among older adults may create significant savings for the health care system. The total potential gain from additional physical activity is substantial, especially for those who are inactive. However, these gains can be materialized if people stay active enough to derive positive health benefits of physical activity. These results, therefore, should be evaluated in the light of findings from related literature on health and physical activity. © Canadian Public Health Association, 2010. Source


Gagnon K.B.,University of Saskatchewan | Di Fulvio M.,Wright State University
Cellular Physiology and Biochemistry | Year: 2013

The homologous genes encoding the electroneutral solute carrier family 12A (SLC12A) were identified more than 20 years ago, however, over the last few years, it has become clear that each of the genes within this family potentially encode for more than one cation-chloride cotransporter (CCC). Even more surprising, despite more than 30 years of functional studies and a wealth of knowledge on the activators, inhibitors, ion affinities, and kinetics of these cotransporters, we still cannot sufficiently explain why some cells express only one CCC isoform, while others express two, three, or more CCC isoforms. In 2009, Drs. Alvarez-Leefmans and Di Fulvio published an extensive in silico molecular analysis of the potential splice variants of the Na +-dependent cation-chloride cotransporters. In this review, we will look at the exceptionally large variety of potential splice variants within the Na+-independent cation-chloride cotransporter (SLC12A4-SLC12A7) genes, their initial tissue identification, and their physiological relevance. © 2014 S. Karger AG, Basel. Source


Sumner D.,University of Saskatchewan
Journal of Fluids and Structures | Year: 2013

The wake of a surface-mounted finite-height circular cylinder and the associated vortex patterns are strongly dependent on the cylinder aspect ratio and the thickness of the boundary layer on the ground plane relative to the dimensions of the cylinder. Above a critical aspect ratio, the mean wake is characterized by streamwise tip vortex structures and Kármán vortex shedding from the sides of the cylinder. Below a critical aspect ratio, a unique mean wake structure is observed. Recent experimental studies in the literature that used phase-averaged techniques, as well as recent numerical simulations, have led to an improved physical understanding of the near-wake vortex flow patterns. However, the flow above the free end of the finite circular cylinder, and its relationship to the near wake, has not been systematically studied. The effects of aspect ratio and boundary layer thickness on the free-end flow field are also not completely understood, nor has the influence of Reynolds number on the free-end flow field been fully explored. Common features associated with the free end include separation from the leading edge, a mean recirculation zone containing a prominent cross-stream arch (or mushroom) vortex, and reattachment onto the free-surface. Other flow features that remain to be clarified include a separation bubble near the leading edge, one or two cross-stream vortices within this separation bubble, the origins of the streamwise tip or trailing vortices, and various critical points in the near-surface flow topology. This paper reviews the current understanding of the flow above the free end of a surface-mounted finite-height circular cylinder, with a focus on models of the flow field, surface oil flow visualization studies, pressure and heat flux distributions on the free-end surface, measurements of the local velocity field, and numerical simulations, found in the literature. © 2013 Elsevier Ltd. Source


Gilchrist S.E.,University of British Columbia | Alcorn J.,University of Saskatchewan
Fundamental and Clinical Pharmacology | Year: 2010

Since solute carrier (SLC) and ATP-binding cassette (ABC) transporters play pivotal roles in the transport of both nutrients and drugs into breast milk, drug-nutrient transport interactions at the lactating mammary gland are possible. Our purpose was to characterize lactation stage-dependent changes in transporter expression in rat mammary gland and isolated mammary epithelial organoids (MEO) to provide additional insight for the safe use of maternal medications during breastfeeding. We used quantitative reverse transcription-polymerase chain reaction to assess the temporal expression patterns of SLC and ABC transporters in rat mammary gland and isolated MEO at different stages of lactation. In whole mammary gland five distinct patterns of expression emerged relative to late gestation: (i) decreasing throughout lactation (Mdr1a, Mdr1b, Mrp1, Octn2, Ent2, Ent3, Ncbt2, Mtx1); (ii) prominent increase in early lactation, which may remain elevated or decline with advancing lactation (Octn1, Cnt2, Cnt3, Ent1, Pept1, Pept2); (iii) constant but decreasing later in lactation (Octn3, Dmt1); (iv) increasing until mid-to-late lactation (Oct1, Cnt1); and (v) prominent increase late in lactation (Ncbt1). In isolated MEO (an enriched source of mammary epithelial cells) major differences in expression patterns were noted for Octn3, Ncbt1, and Mtx1, but otherwise were reasonably similar with the whole mammary gland. In conclusion our study augments existing data on transporter expression in the lactating mammary gland. These data should facilitate investigations into lactation-stage dependent changes in drug or nutrient milk-to-serum concentration ratios, the potential for drug- or disease-transporter interactions, and mechanistic studies of transporter function in the lactating mammary gland. © 2009 Société Française de Pharmacologie et de Thérapeutique. Source


Westbrook C.J.,University of Saskatchewan | Cooper D.J.,Colorado State University | Baker B.W.,U.S. Geological Survey
River Research and Applications | Year: 2011

We examined how beaver dams affect key ecosystem processes, including pattern and process of sediment deposition, the composition and spatial pattern of vegetation, and nutrient loading and processing. We provide new evidence for the formation of heterogeneous beaver meadows on riverine system floodplains and terraces where dynamic flows are capable of breaching in-channel beaver dams. Our data show a 1.7-m high beaver dam triggered overbank flooding that drowned vegetation in areas deeply flooded, deposited nutrient-rich sediment in a spatially heterogeneous pattern on the floodplain and terrace, and scoured soils in other areas. The site quickly de-watered following the dam breach by high stream flows, protecting the deposited sediment from future re-mobilization by overbank floods. Bare sediment either exposed by scouring or deposited by the beaver flood was quickly colonized by a spatially heterogeneous plant community, forming a beaver meadow. Many willow and some aspen seedlings established in the more heavily disturbed areas, suggesting the site may succeed to a willow carr plant community suitable for future beaver re-occupation. We expand existing theory beyond the beaver pond to include terraces within valleys. This more fully explains how beavers can help drive the formation of alluvial valleys and their complex vegetation patterns as was first postulated by Ruedemann and Schoonmaker in 1938. © 2010 John Wiley & Sons, Ltd. Source


Wiens T.,University of Saskatchewan
Journal of Vibration and Acoustics, Transactions of the ASME | Year: 2016

This paper presents a numerical method of tracing of sound or other refracted rays through a medium with arbitrarily varying refractive index. The method uses a radial basis function (RBF) network to define the refractive index of the medium, allowing continuous gradients to be determined analytically and the ray path to be solved using standard numerical ordinary differential equation (ODE) solution techniques. Copyright © 2016 by ASME. Source


Seshia S.S.,University of Saskatchewan | Young G.B.,University of Western Ontario
Canadian Journal of Neurological Sciences | Year: 2013

In Part 2, we discuss the challenges of keeping up with the 'literature,' evidence-based medicine (EBM) in emerging economies and the Neurosciences, and two recent approaches to classifying evidence. We conclude by summarizing information from Parts 1 and 2 which suggest the need to critically re-appraise core elements of the EBM paradigm: (1) the hierarchical ranking of evidence, (2) randomized controlled trials or systematic reviews as the gold standard for all clinical questions or situations, (3) the statistical tests that have become integral to the 'measurements' for analyzing evidence, and (4) re-incorporating a role for evidence from basic sciences and pathophysiology. An understanding of how cognitive processes influence clinical decisions is also necessary to improve evidence-based practice. Emerging economies may have to modify the design and conduct of clinical research to their settings. Like all paradigms, EBM must keep improving with input from the grassroots to remain beneficial. Source


Seshia S.S.,University of Saskatchewan | Young G.B.,University of Western Ontario
Canadian Journal of Neurological Sciences | Year: 2013

The evidence-based medicine (EBM) paradigm, introduced in 1992, has had a major and positive impact on all aspects of health care. However, widespread use has also uncovered some limitations; these are discussed from the perspectives of two clinicians in this, the first of a two part narrative review. For example, there are credible reservations about the validity of hierarchical levels of evidence, a core element of the EBM paradigm. In addition, potential and actual methodological and statistical deficiencies have been identified, not only in many published randomized controlled trials but also in systematic reviews, both rated highly for evidence in EBM classifications. Ethical violations compromise reliability of some data. Clinicians need to be conscious of potential limitations in some of the cornerstones of the EBM paradigm, and to deficiencies in the literature. Source


Walsh M.,National University of Ireland | Morrison T.G.,University of Saskatchewan | McGuire B.E.,National University of Ireland
Pain | Year: 2011

This study examined chronic pain in adults with an intellectual disability (ID), in terms of its prevalence, impact on physical and psychological functioning, and treatments used. Questionnaires were distributed to 2378 primary caregivers (caregivers) of community-dwelling adults with an ID. The questionnaires were used to gather data on demographics, general health, nature of pain, impact of pain, treatment, and health-related decision making. Responses were received from 753 caregivers (31.6% response rate). Caregivers reported that 15.4% of this sample was experiencing chronic pain, for an average of 6.3 years. Significantly more females than males were reported to experience chronic pain, although age, communication ability, and level of ID were not found to be associated with the presence of pain. However, the presence of pain was associated with cerebral palsy, physical disability, and reports of challenging behaviour. A significant proportion of individuals with chronic pain also experienced limitations in several aspects of daily living, and more than 78% of caregivers reported that the service user had become upset or distressed by pain. More than 80% of service users were receiving some form of treatment for their pain, with most seeing a family physician and using analgesics as the primary form of pain treatment. Results indicate that chronic pain is a significant problem for persons with an ID, with a proportion of service users living with daily pain for many years and experiencing limitations in daily functioning, emotional well-being, and quality of life. © 2011 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved. Source


Beland D.,University of Saskatchewan
Journal of Health Politics, Policy and Law | Year: 2010

Explaining policy change is one of the most central tasks of contemporary policy analysis. Reacting to overly rigid institutionalist frameworks that emphasize stability rather than change, a growing number of scholars have formulated new theoretical models to shed light on policy change. Focusing on health care reform but drawing on the broader social science literature on policy and politics, this article offers critical perspectives on the institutionalist and ideational literatures on policy change while assessing their relevance for analyzing change in contemporary health care systems. The last section sketches a research agenda for studying policy change in health care. © 2010 by Duke University Press. Source


Ferrari M.C.O.,University of California at Davis | Chivers D.P.,University of Saskatchewan
Behavioral Ecology and Sociobiology | Year: 2010

Amphibians are able to learn to recognize their future predators during their embryonic development (the ghost of predation future). Here, we investigate whether amphibian embryos can also acquire additional information about their future predators, such as the level of threat associated with them and the time of day at which they would be the most dangerous. We exposed woodfrog embryos (Rana sylvatica) to different concentrations of injured tadpole cues paired with the odor of a tiger salamander (Ambystoma tigrinum) between 1500 and 1700 hours for five consecutive days and raised them for 9 days after hatching. First, we showed that embryos exposed to predator odor paired with increasing concentrations of injured cues during their embryonic development subsequently display stronger antipredator responses to the salamander as tadpoles, thereby demonstrating threat-sensitive learning by embryonic amphibians. Second, we showed that the learned responses of tadpoles were stronger when the tadpoles were exposed to salamander odor between 1500 and 1700 hours, the time at which the embryos were exposed to the salamander, than during earlier (1100-1300 hours) or later (1900-2100 hours) periods. Our results highlight the amazing sophistication of learned predator recognition by prey and emphasize the importance of temporal considerations in experiments examining risk assessment by prey. © 2009 Springer-Verlag. Source


Hojati M.,University of Saskatchewan
Computers and Industrial Engineering | Year: 2016

In this paper we address the 2-stage m-machine (in Stage 2) disassembly flow-shop (2SmMDF) scheduling problem. It consists of n jobs, each requiring m+1 tasks. The first task is the disassembly of a job, and it leads to m processing tasks each of which is performed on a different machine. The objective is to minimize the make-span. First we show that 2SmMDF problem for the make-span criterion is NP-complete. Then we propose the following three heuristic methods for its solution: H1: determine the maximum of Stage 2 task times for each job and use that and the time required for the first task to schedule the jobs according to the Johnson's rule; H2: determine the total time required at each Stage 2 machine over all the jobs and use the time of the machine with the largest total time and the time required for the first task to schedule the jobs according to the Johnson's rule; H3: determine the average of Stage 2 times for each job and use that and the time required for the first task to schedule the jobs according to the Johnson's rule. Finally, we present the worst-case performance analysis for each method, and show that method H3 has a slightly better worst-case performance bound. © 2016 Elsevier Ltd. All rights reserved. Source


Davidson R.K.,Norwegian Veterinary Institute | Romig T.,University of Hohenheim | Jenkins E.,University of Saskatchewan | Tryland M.,Section for Arctic Veterinary Medicine