PURPOSE: To establish the reliability of anthropometric and dual energy X-ray absorptiometry(DXA) techniques used to assess percent body fat (% BF)in female athletes; to establish limits for detecting the smallest real change in % BF associated with anthropometric and DXA testing;to evaluate the validity of commonly used % BF prediction equations recommended by national certification programs along with equations derived from Multicompartment (MC), and DXA, in female athletes; and to create a new DXA based regression equation for elite female athletes. METHODS:Female athletes aged 17-31 were recruited into the study and participated in the establishment of anthropometric reliability (N=20), DXA reliability (N=32), and /or skinfold validity (N=95) testing. Anthropometric testing consisted of measurements of skinfolds,circumferences, and breadths. DXA measurements were conducted using a GE Lunar Prodigy DXA which served as the criterion measure (% BF DXA). RESULTS: Excellent reliability for both anthropometric sum5 skinfolds (ICC= .997, %TEM=0.9 %) and DXA (ICC =.996, CV =1.13% BF) techniques allows for detection of smallest real differences of 2.2 mm and 721g in summed skinfolds (sum5) and fat mass respectively. The DXA based equation of Ball et al.(2004) displayed the greatest validity of existing equations R=.874, total error (TE) 2.9% BF, and Bland Altman Limits of Agreement -4.7to 6.5 % BF. The newly created regression equation demonstrated a non-linear characteristic and displayed similar predictive ability R= .840, TE 3.0%BF, and Bland Altman Limits of Agreement of -6.1to 6.1 % BF. CONCLUSIONS: Anthropometric equations derived from various criteria yielded dissimilar results. Long utilized popular equations advocated in national accreditation schemes (ACSM, CSEP) show considerable bias compared to modern values obtained by current DXA technology. A new regression equation was created for female Canadian athletes 17-31yrs of age using skinfolds taught in the Canadian national professional certification program (CSEP).

Serotonin receptor subtypes 5-HT1A, 5-HT2A and 5-HT2C are expressed in motoneurons and modulate motoneuron excitability. Serotonergic neurons, which increase their discharge with motor activity, make numerous contacts with motoneurons; however, little is known about the adaptability of motoneuron serotonin receptor expression in response to exercise. The purpose of this study was to determine the effect of a 7-day treadmill exercise protocol on 5-HT1A, 5-HT2A and 5-HT2C receptor mRNA levels in rat lumbar motoneurons. Lumbar motoneurons of exercised and sedentary animals were collected via laser capture microdissection. RNA was isolated from these samples and real-time reverse transcription polymerase chain reactions were performed to determine differences in receptor mRNA levels between exercised and sedentary animals. It appears that 5-HT1A, 5-HT2A and 5-HT2C receptor mRNA levels are unaltered following 7 days of treadmill exercise; however, future research must be done to determine if an exercise effect exists when motoneurons are differentiated by type.

Abstract The ability of several plant-associated bacteria to inhibit the proliferation of root-pathogens has been well established whereas considerably less has been reported about bacterial species inhibiting pathogens on the phylloplane. Sclerotinia sclerotiorum is the fungal causative agent of stem rot and is capable of infecting over 400 plant species, including flowering canola plants. For this reason, there is a need for disease management strategies targeted at preventing sclerotinia infection. Pseudomonas species DF41 was isolated from the canola rhizosphere and found to be an excellent antagonist of sclerotinia stem rot. Therefore, research efforts turned towards elucidating the mechanisms underlying DF41 antifungal (AF) activity. A random transposon mutagenesis approach facilitated the identification of genes essential for DF41 fungal antagonism. One gene that was identified, gacS, encodes the sensor kinase of the Gac two-component signal transduction system. Characterization of the DF41 gacS mutant revealed that this regulator is essential for secondary metabolite production. In other bacteria, the Gac system activates target gene expression by upregulating the transcription of small, untranslated RNA molecules (sRNA). A sRNA molecule called RsmZ was found to act as a downstream regulatory element in the DF41 Gac regulatory cascade. Furthermore, we discovered that DF41 is producing acyl homoserine lactone (AHL) signalling molecules. This prompted us to investigate the effect of quorum sensing (QS) on phenotypes contributing to AF activity. In DF41, AHL- signalling is not important for secondary metabolite production but does influence motility and may indirectly govern gene expression by controlling other regulatory elements Screening of our transposon library led to the identification of a non-ribosomal peptide synthetase gene involved in synthesis of a cyclic lipopeptide (CLP) molecule. High-performance liquid chromatography (HPLC) and mass spectrometry (MS) enabled the identification of an unusual CLP and we propose a preliminary structure containing some unique features. The role of this molecule in Pseudomonas sp. DF41 AF activity was also elucidated. Altogether, this investigation has revealed a number of important findings regarding how DF41 functions as a biocontrol agent. This information will allow us to use DF41 more effectively in the future in managing sclerotinia stem rot on canola plants.

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.