Background. Estimates are that one third of children will develop type 2 diabetes in their lifetime. Lifestyle changes, including physical activity are established effective tools to prevent and manage type 2 diabetes in adults but the evidence in youth is lacking. Several key questions remain including: (1) Can youth with type 2 diabetes achieve target glycemic control with lifestyle changes alone? (2) Is type 2 diabetes in youth associated with low physical activity and cardiorespiratory fitness? and (3) What is the appropriate intensity of physical activity to reduce the risk for type 2 diabetes in overweight youth? Methods. Three studies were conducted to answer these questions: i) a retrospective chart review to determine the clinical efficacy of lifestyle monotherapy to manage glycemia in youth newly diagnosed with type 2 diabetes; ii) a cross sectional study to test the association between physical activity, cardiorespiratory fitness and type 2 diabetes risk factors in youth; and iii) a randomized controlled trial of physical activity designed to determine the training intensity required to improve insulin resistance and reduce intrahepatic lipid content in overweight youth at risk for type 2 diabetes (interim results presented). Results. Study A. Over 50% of youth newly diagnosed with type 2 diabetes and glycosylated hemoglobin ≤9% were able to achieve target glycemic control for as long as 12 months with lifestyle monotherapy. Study B. Physical activity levels (4905±2075 vs. 6937±2521 vs. 8908±2949 steps/day, p<0.05 vs. healthy weight youth) and cardiorespiratory fitness (23.4±5.9 vs. 26.7±6.0 vs. 36±6.6 ml/kg/min, ii p<0.05) are lower in youth with type 2 diabetes versus overweight and healthy weight controls. Intrahepatic lipid is significantly higher (13.0%±14.1 vs. 5.6%±6.2 vs. 1.4%±1.4, p<0.05) and inversely associated with insulin sensitivity (r = -0.40, p<0.001). Study C. Interim analyses present promising trends from a 6-month physical activity intervention. Conclusions. Lifestyle therapy can be an effective tool to manage new-onset diabetes in certain youth, and is also important in the prevention of type 2 diabetes in youth. Youth with type 2 diabetes are characterized by low levels of physical activity and cardiorespiratory fitness. Interim results are presented from a randomized controlled physical activity trial that we anticipate at completion will provide promising data to guide development of community-based programming to reduce risk for type 2 diabetes in overweight youth.

This thesis presents a linearized technique to determine a risk-based index for dynamic security. The method is an extension to an existing technique in which the risk of steady state security is calculated using the mean and variance of load uncertainty. The proposed method is applied to calculate the risk indices for the New England 39 bus test system. The results obtained from the proposed method are validated against those estimated by Monte Carlo simulation. Both approaches produce virtually the same results for small load deviations.

Broad Whitefish are an anadromous Arctic fish species in the Mackenzie River Valley, N.W.T. that undergo extensive spawning migrations to spawning grounds located on tributaries of the Mackenzie River, like the Arctic Red River. These spawning migrations occur annually between mid-October and early November as demonstrated with catch-per-unit-effort. The maturity stage development of Broad Whitefish is can be predicted by using the variables by gonad-weight and timing of migration for both female and male Broad Whitefish; however, male Broad Whitefish maturity stage also requires the variable abundance for prediction. At the time of Broad Whitefish migration the river environment has slow flowing water as documented by current profiles. The water velocity speeds present in the river at the time of migration are not a barrier to Broad Whitefish migration as Broad Whitefish can swim against water velocities 4 to 10 times higher. This research contributes important life history, migrating characteristic and swimming ability information to the knowledge of Broad Whitefish in the Mackenzie River System.

The issue of eddy currents induced by the rapid switching of magnetic field gradients is a long-standing problem in magnetic resonance imaging. A new method for dealing with this problem is presented whereby spatial harmonic components of the magnetic field are continuously sensed, through their temporal rates of change, and corrected. In this way, the effects of the eddy currents on multiple spatial harmonic components of the magnetic field can be detected and corrections applied during the rise time of the gradients. Sensing the temporal changes in each spatial harmonic is made possible with specially designed detection coils. However to make the design of these coils possible, general relationships between the spatial harmonics of the field, scalar potential, and vector potential are found within the quasi-static approximation. These relationships allow the vector potential to be found from the field – an inverse curl operation – and may be of use beyond the specific problem of detection coil design. Using the detection coils as sensors, methods are developed for designing a negative feedback system to control the eddy current effects and optimizing that system with respect to image noise and distortion. The design methods are successfully tested in a series of proof-of-principle experiments which lead to a discussion of how to incorporate similar designs into an operational MRI.

Modern data analysis often involves a large number of variables, which gives rise to the problem of multicollinearity in regression models. It is well-known that in a linear model, when the design matrix X is nearly singular, then the ordinary least squares (OLS) estimator may perform poorly because of its numerical instability and large variance. To overcome this problem, many linear or nonlinear biased estimators are studied. In this work we consider a class of generalized shrunken least squares (GSLS) estimators that include many well-known linear biased estimators proposed in the literature. We compare these estimators under the mean square error and matrix mean square error criteria. Moreover, a simulation study and two numerical examples are used to illustrate some of the theoretical results.

The investigation of a species’ repertoire and the contexts in which different calls are used is central to understanding vocal communication among animals. Beluga whale, Delphinapterus leucas, calls were classified and described in association with behaviours, from recordings collected in the Churchill River, Manitoba, during the summers of 2006-2008. Calls were subjectively classified based on sound and visual analysis into whistles (64.2% of total calls; 22 call types), pulsed or noisy calls (25.9%; 15 call types), and combined calls (9.9%; seven types). A hierarchical cluster analysis, using six call measurements as variables, separated whistles into 12 groups and results were compared to subjective classification. Beluga calls associated with social interactions, travelling, feeding, and interactions with the boat were described. Call type percentages, relative proportions of different whistle contours (shapes), average frequency, and call duration varied with behaviour. Generally, higher percentages of whistles, more broadband pulsed and noisy calls, and shorter calls (<0.49s) were produced during behaviours associated with higher levels of activity and/or apparent arousal. Information on call types, call characteristics, and behavioural context of calls can be used for automated detection and classification methods and in future studies on call meaning and function.

African refugees and immigrants are arriving in Manitoba in vastly increasing numbers and a review of the literature indicates that they are experiencing barriers to successful integration. The goals of this research are to understand the experiences of Sierra Leonean newcomers with seeking support and identify specific needs and services that might be helpful. Using qualitative methods, interviews were conducted with Sierra Leonean newcomers. The analysis of the data indicates that newcomers want financial independence and to fit into Canadian life. The process to get their foreign credentials accredited is difficult and affects their ability to gain economic security. They rely on informal networks with other Sierra Leoneans for assistance to acquire resources when they are unable to get help from service providers. As well, newcomers are concerned about their community image, feelings of isolation and sacrificing all of their dreams. Recommendations from this study include the need to recognize and support African community leaders in connecting with newcomers to share accurate and vital information. In addition, services for employment and the accreditation of foreign credentials should be appropriate, affordable and timely. Changes to policies and to the provision of settlement services are necessary to improve the accessibility and availability of resources required for the successful integration of African newcomers.

Manitoba’s population is aging. Trends in personal care home (PCH) use have also changed so that residents today have more cognitive impairments including Alzheimer’s disease and related dementias (ADRD). While quality of life (QoL) has emerged as an important PCH research outcome, this literature is relatively sparse for residents with versus without ADRD. This study was conducted to examine the QoL of PCH residents with ADRD, using a recently developed but as of yet untested framework by Kane and colleagues (1999, as cited in Frytak; Kane 2001, 2003). The specific aims of this study were to gather family caregivers’ perspectives on: (a) the meaning of the six domains that constitute Kane et al.’s ADRD-specific PCH-QoL framework; (b) domains they considered to be more important or lacking from this framework; and, (c) general PCH policies, practices, and activities that currently (or could better) facilitate positive QoL experiences for their loved ones.

Traumatic brain injury (TBI) has a 20% mortality rate and a 10-15% rate of resultant permanent disability. The consequences of TBI range from brief loss of consciousness, to prolonged coma or death. Mild TBI is amongst the common causes of admission to trauma centers all over the world. Future technologies such as magnetic resonance elastography and robotic surgery demand information about the physical properties of brain tissue. Walsh and Schettini described the mechanical behavior of brain tissue under normal status as nonlinear viscoelastic behavior and defined the associated biomechanical changes and responses in a quantitative measurement of the material changes. Yet, there is still a lack of data concerning time-dependent deformation and mechanical property changes associated with TBI. My goal in this project was to describe these mechanical responses and to create a system for measuring and evaluating the mechanical response of brain tissue in vivo. This was to be achieved by inducing cortical contusions with a calibrated weight-drop method in seventy-four young adult male Sprague-Dawley rats. Instrumented indentation was performed on control brains and 1 hour to 3 weeks after contusion with intact dura using a 4-mm-diameter flat punch indenter to a maximum depth of 1.2 mm at loading. Loading rates did not exceed 0.34 N/min and 1.2 mm/min. In order to obtain force displacement data, we studied the elastic response of the traumatized brain tissue and the deformation process (creep) during the loading and unloading of indenter. After euthanasia, the brain was removed and evaluated histologically with different methods to reveal acute and chronic changes related to the contusion. The results revealed that the biomechanical properties of the brain tissue were changed after cortical contusion. Brain tissue elasticity decreased in the edematous brain at one day following the contusion and increased at 3 weeks, in association with reactive astroglial changes. This experimental technique, combined with mathematical modeling, might eventually lead to a better understanding of the physical changes in brain following TBI.

Detecting the presence of insects at low densities can avoid total deterioration of stored grains because corrective actions can be implemented early. Tribolium castaneum (Herbst) and Cryptolestes ferrugineus (Stephens) are the major insect pests of the Canadian grain handling industry. Identification of the volatile organic compounds released by insects can be used to detect insects in stored grains. An attempt was made to identify the volatile organic compounds released by T. castaneum and C. ferrugineus by headspace analysis. The volatiles in the head space of vials with insects, insects and wheat flour, and insects and wheat, were analyzed using a GC-MS coupled with an automatic headspace sampler. Wheat with fifteen percent moisture content was used in this study along with two different insect densities. Feasibility of the automatic headspace sampler in headspace analysis was found to be positive. The sampler can do sample conditioning, absorption, trap cleaning and desorption of the volatiles into the GC-MS and speed up the process. The samples extracted at 20 strokes with 1000 µL per stroke, and desorbed at 250°C gave a clear peak of compounds. The amount of volatiles produced by T. castaneum adults varied based on insect densities, the concentration of Methyl-1, 4-benzoquinone; Ethyl-1, 4-benzoquinone; and 1-Tridecene released by ten adult insects were 355, 390 and 530 µg/L compared to 300,310 and 210 µg/L of Methyl-1, 4-benzoquinone; Ethyl-1, 4-benzoquinone; and 1-Tridecene produced by five adult insects. Extreme high and low temperature leading to death produced very high amounts of volatiles compared to insects kept at 35°C. The larvae of the T. castaneum insects did not produce any volatiles at ambient condition as well as at extreme cold and warm conditions. The C. ferrugineus adults did not produced any detectable amount of volatiles even at the higher insect density after up to 3 days. The results of the combination of T. castaneum and C. ferrugineus insects gave the same volatile organic compounds as produced by T. castaneum insects alone. The 1-Tridecene produced by T. castaneum was not reported previously in other studies.