Manitoba Heritage Theses
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Contains full text Manitoba-related theses dating from 1902 to the present.
The University of Manitoba Libraries gratefully acknowledges the financial support of the Manitoba Department of Heritage, Culture, Tourism and Sport in the digitization of many of these theses.
The University of Manitoba Libraries gratefully acknowledges the financial support of the Manitoba Department of Heritage, Culture, Tourism and Sport in the digitization of many of these theses.
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- ItemOpen AccessTransnational circuits of precarity: a qualitative examination of temporary worker wellbeing in Manitoba(2025-02-11) Huynh, Anthony; Chase, Robert (Community Health Sciences); Varley, Emma (Community Health Sciences); Sethi, Bharati (Trent University); Marcelino, Diwa (Migrante Manitoba); Lorway, Robert; Hatala, AndrewABSTRACT Background In western Canada, Manitoba is a critical hub for a large population of migrant workers. Usually with limited English or French language ability and possessing limited rights and protections under the current TFWP, Temporary foreign workers (TFWs) are often tied to a single employer, leaving them vulnerable to employer abuse and the under-reporting of workplace injuries and illnesses due to the threat of deportation. Within the context of the COVID-19 pandemic, when my dissertation research began, the many cases seen among TFWs in Manitoba raises additional important public health questions on the health and wellbeing of migrant workers in Manitoba that I discuss in this dissertation. Methodology In close collaboration with Migrante Manitoba (MB), I conducted a qualitative study to explore the precarious lives of migrant workers during the COVID-19 pandemic. I virtually interviewed 20 migrant workers who entered Canada through the TFWP, employed either as seasonal agricultural workers (n=7) or TFWs (n=13). Thirteen TFWs came from Philippines and seven farmworkers from Mexico (n=6) and Jamaica (n=1). Theoretical contribution I developed the notion of transnational circuits of precarity to understand the multiple temporal-spatial layers of precarity that migrant workers encounter along their journeys to Manitoba. This multivalent concept is comprised of the following interconnected pieces: 1) a broader political economic “force-field” that compels the movement of human labour resources from the global South to the global North; 2) the rigid and regulated pathway put in place to ensure workers arrival at their work destinations; 3) the process of making “model minorities” through training programs that ensure the “smooth” transition of workers in their host country; and 4) the affective economy that is fueled by workers’ hopes, dreams, and desires. All together, these seemingly disparate processes articulate to produce complex temporal and spatial realities that shape the precarious trajectories of migrant workers. Such a paradigm shift away from the narrow temporal and spatial limits of a focus on “occupational health hazards” will be critical if workers are to realize any meaningful and substantive changes to their overall physical and mental well-being.
- ItemOpen AccessOptimization of in vitro RNA interference assays to reduce variability in target gene knockdown in the phytopathogen Sclerotinia sclerotiorum(2025-01-16) Fatema, Reemana; Gerstein, Aleeza (Microbiology); Marcus, Jeffrey (Biological Sciences); Whyard, SteveSclerotinia sclerotiorum is a broad host range fungal phytopathogen that is the causal agent of Sclerotinia stem rot in many crop plants, causing devastating yield losses worldwide. Sclerotinia is partially controlled using broad-spectrum chemical fungicides, but new, more species-specific fungicides, such as double-stranded RNAs, are being considered as safer alternatives. This study evaluated the effectiveness of long double-stranded RNAs (dsRNAs) and paperclip RNAs (pcRNAs) to induce gene silencing in two different fungal inoculants of S. sclerotiorum. The three different genes that were targeted in this study, SS1G_01703, SS1G_00005, SS1G_14116, are all involved in different aspects of S. sclerotiorum’s infection process i.e. pathogenicity, encoding 60S ribosomal unit and mycelial growth respectively. Initial dsRNA experiments using small fungal plugs collected from solid media generally resulted in highly variable levels of transcript knockdown, potentially arising from unequal hyphal amounts in treatment tubes. This led to the development of fungal slurries as the inoculum to provide a more uniform distribution of hyphae across all the samples. The slurry method resulted in significant transcript knockdowns using all three long dsRNAs at different doses, although some variability persisted. The variability using the slurry method was linked to potential differences in hyphal developmental stages, age of hyphae and differences in expression levels of each target gene. In contrast, structurally different and shorter in length pcRNAs failed to induce consistent transcript knockdown in both plug and slurry assays, despite earlier reports of their efficacy in reducing lesion sizes on canola leaves. This inefficacy may stem from pcRNAs' reliance on a single siRNA for gene targeting, potentially insufficient to overcome the structural complexity of target mRNAs. These findings highlighted the potential of long dsRNAs for gene knockdown in S. sclerotiorum using optimized slurry-based assays, while suggesting that pcRNAs require further modifications. Future work can explore alternative siRNA designs, increased pcRNA doses, and identifying accessible mRNA regions to improve knockdown efficiency. Additionally, optimizing the methods to assess hyphal developmental stages and minimizing variability during sample preparation are crucial for reproducibility and accuracy in RNAi-based studies.
- ItemOpen AccessGenome-wide association analysis within The Manitoba Personalized Lifestyle Research study(2024-12-19) Badurally Adam, Bibi Taskeen; Myrie, Semone (Food and Human Nutritional Sciences); Mackay, Dylan (Food and Human Nutritional Sciences); Taylor, James (Food and Human Nutiritional Sciences); Eck, Peter; Hu, PingzhaoOverall Abstract Background: Obesity is a major public health challenge worldwide and in Manitoba. An estimated 40-70% of obesity is heritable; however, these genetic associations are poorly investigated in the Manitoban adult population using the “gold standard” Dual Energy X-Ray Absorptiometry (DXA) to assess obesity phenotypes. The Manitoba Personalized Lifestyle Research (TMPLR) project enabled a genetic association study in middle-aged Manitobans. Obesity phenotypes considered are total, gynoid, android, arms, legs, and trunk fat mass. Objectives: 1. Perform a systematic review to determine genes associated with obesity phenotypes assessed by DXA in middle-aged cohorts. 2. Develop a “pipeline” to conduct Genome-Wide Association Studies (GWAS) within the TMPLR. 3. Conduct a GWAS on obesity phenotypes within TMPLR. 4. Compare the genes from the systematic review to those from TMPLR data analysis. Methods: The Covidence platform was used for the systematic review. Publications up to July 2023 sourced from Embase and Medline. The methods for the TMPLR project have been published. A GWAS pipeline was established using the Biodata Catalyst bioinformatics platform and the Seven Bridges R studio version 4.1. Results: Out of 94 and 25 studies obtained from Medline and Embase respectively, 14 studies met the eligibility criteria and 13 genes were identified that are associated with obesity-related phenotypes. No significant genome-wide association with obesity was established in the TMPLR cohort. However, 23 loci have had suggestive associations with the obesity phenotypes. Conclusion: There is a lack of high-quality genetic studies that use DXA data and adult populations. No genome-wide associations were reported in TMPLR, likely due to the limited sample size of the cohort. However, a bioinformatics pipeline to analyze genome-wide associations in TMPLR cohort is established and can be used for larger cohorts, such as UK biobanks.
- ItemOpen AccessElucidating factors that influence infection success and the behaviour of gastropod hosts of Echinostoma trivolvis lineage c(2025-01-03) Hodinka, Cameron; Van Nest, Byron (Biological Sciences); Wyeth, Russell (St. Francis Xavier University); Detwiler, JillianWildlife trematodes are important to study due to their impact on wildlife populations, including the ability to modify the behaviour of their hosts. However, these parasites are challenging to study without a fully elucidated life cycle that can be completed in a laboratory. As such, a model for wildlife trematodes would be a great asset for learning about the ecology and behavioural manipulation found in this group. I chose Echinostoma trivolvis lineage c as a parasite model to study these topics in gastropod hosts. Chapter 1 determined how host species/morphotype, host size and miracidial dose affects infection success of gastropod first intermediate hosts. I confirmed reports from natural infections that Ladislavella elodes is a host along with it’s morphotype Stagnicola reflexa and further determined which size and exposure dose produced the highest infection success. I used this new information to obtain infected hosts for my second chapter of my thesis. Herein, I tested whether light and species influenced the navigational behaviour of potential second intermediates host L. elodes. I determined that snail velocity increased when exposed to a higher light level. Using these higher light conditions, I also found that there was no attraction to infected conspecific hosts by potential second intermediate hosts. Both experiments suggest that abiotic and biotic factors can alter snail navigational behaviour and may even influence whether host behavioural modification is observed. As such, laboratory-based studies of behavioural modification may be over or underestimating the strength and frequency of the behaviours that may be occurring in nature. Examples of naturally occurring behavioural modification may be missed entirely if not tested under the right context in the laboratory.
- ItemOpen AccessInvestigating markers of Alzheimer’s disease in posttraumatic stress disorder using machine learning and magnetic resonance imaging(2024-12-19) Yakemow, Gabriella; Hryniuk, Alexa (Human Anatomy and Cell Science); Bolton, Shay-Lee (Psychiatry); Ko, Ji HyunIntroduction: Posttraumatic stress disorder (PTSD) is a mental health disorder caused by experiencing or witnessing traumatic events. Recent studies show that patients with PTSD have an increased risk of developing dementia, including Alzheimer’s disease (AD), but there is currently no way to predict which patients will go on to develop AD. The objective of this study was to identify structural and functional neural changes in patients with PTSD that may contribute to the future development of AD. Methods: Neuroimaging (pseudo-continuous arterial spin labelling [pCASL] and structural magnetic resonance imaging [MRI]) and behavioral data for the current study (n = 67) were taken from our non-randomized, open label clinical trial (ClinicalTrials.gov Identifier: NCT03229915) for treatment-seeking individuals with PTSD (n = 40) and age-matched healthy controls (HC; n = 27). Only the baseline measures were utilized for this study. Mean cerebral blood flow (CBF) and grey matter (GM) volume were compared between groups. Additionally, we utilized two previously established machine learning-based algorithms, one representing AD-like brain activity (Machine learning-based AD Designation [MAD]) and the other focused on AD-like brain structural changes (AD-like Brain Structure [ABS]). MAD scores were calculated from pCASL data and ABS scores were calculated from structural T1-MRI images. Correlations between neuroimaging data (regional CBF, GM volume, MAD scores, ABS scores) and PTSD symptom severity scores measured by the clinician-administered PTSD scale for DSM-5 (CAPS-5) were assessed. Results: Decreased CBF was observed in two brain regions (left caudate/striatum and left inferior parietal lobule/middle temporal lobe) in the PTSD group, compared to the HC group. Decreased GM volume was also observed in the PTSD group in the right temporal lobe (parahippocampal gyrus, middle temporal lobe), compared to the HC group. GM volume within the right temporal lobe cluster negatively correlated with CAPS-5 scores and MAD scores in the PTSD group.Conclusion: Results suggest that patients with PTSD with reduced GM volume in the right temporal regions (parahippocampal gyrus) experienced greater symptom severity and showed more AD-like brain activity. These results show potential for early identification of those who may be at an increased risk for future development of AD.