Theses, Dissertations, and other Required Graduate Degree Essays

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This collection contains digitized SFU theses except for those theses submitted within the last 12 months. If you cannot find the thesis you are looking for please search Recently Submitted Theses as it may be a recently submitted thesis and thus not yet available in Summit.

Public trust in health authorities: Examining Twitter comments on CDC and Fauci during Covid-19

Author: 
Date created: 
2021-08-30
Abstract: 

The purpose of the study is to examine public trust in health authorities during COVID-19 and whether individuals' trust in health authorities is influenced by inconsistent health messages. Considering the origin of public trust in the public sphere, the study focuses on the online form of the public sphere- Twitter. As many studies in health communication have implemented large-scale approaches to investigate Twitter data, this study offers a qualitative analysis by conducting a close reading of tweets that mention the Center of Disease Control and Prevention (CDC) and Dr. Anthony Fauci. The results of this research suggest that inconsistency in health guidance and information may potentially hinder public trust in health authorities. Specifically, inconsistency in numbers of COVID-19 metrics may significantly influence individual perceptions of the trustworthiness of health authorities. The rhetorical implications of research findings also suggest that existing partisan divides and general concerns in science may also shape how the public fails to trust during the COVID-19 pandemic.

Document type: 
Graduating extended essay / Research project
File(s): 
Supervisor(s): 
Sun-ha Hong
Department: 
Communication, Art & Technology: School of Communication
Thesis type: 
(Extended Essay) M.A.

Assessment and development of mitigation strategies for membrane durability in fuel cells

Author: 
Date created: 
2021-07-22
Abstract: 

Fuel cell membranes undergo simultaneous or individual chemical and mechanical degradation under dynamic fuel cell operating conditions. This combined stress development effect compromises the functionality of the membrane and ultimately, the overall durability of the fuel cell system. Therefore, it is critical to understand the underlying degradation mechanisms and failure modes under operational conditions. In this thesis, an extensive research methodology including accelerated stress tests, visualization techniques, and finite element modeling is adopted in order to understand and mitigate membrane degradation. The membrane characterization is facilitated using a non-invasive laboratory-based X-ray computed tomography (XCT) system for 3D visualization of membrane damage progression over the lifetime of the fuel cell. The 3D XCT approach is first applied to understand the degradation mechanism responsible for combined chemical and mechanical membrane degradation. The XCT approach is further expanded to 4D in situ visualisation through periodic same location tracking within a miniature operational fuel cell. Fuel cell membranes with mechanical reinforcements and chemical additives are tested as existing mitigation strategies for the isolated degradation stressors. Under pure chemical degradation, the chemically and mechanically reinforced membrane does not show membrane thinning or shorting sites and exceeds the lifetime of the non-reinforced membrane by 2x. The reinforced membrane also mitigated/delayed the crack development during pure mechanical degradation as compared to the non-reinforced membrane. However, significant membrane degradation is still observed and attributed to buckling and delamination mechanisms within the membrane electrode assembly (MEA). Mitigation of these mechanisms is demonstrated through two novel approaches proposed in this thesis: i) reduced surface roughness gas diffusion layers (GDLs); and ii) bonded MEAs. Both mitigation strategies are tested using the same experimental workflow and shown to provide substantial mitigation against fatigue driven mechanical membrane degradation via reduced membrane buckling, resulting in a doubling of the test lifetime in each case. Complementary finite element simulations corroborate the experimental findings and further estimate the critical GDL void sizes to prevent membrane buckling and the required interfacial MEA adhesion quality to stabilize the MEA for improved membrane durability.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Erik Kjeang
Department: 
Applied Sciences: School of Mechatronic Systems Engineering
Thesis type: 
(Thesis) Ph.D.

Sequence clustering for genetic mapping of binary traits

Date created: 
2021-08-24
Abstract: 

Sequence relatedness has potential application to fine-mapping genetic variants contributing to inherited traits. We investigate the utility of genealogical tree-based approaches to fine-map causal variants in three different projects. In the first project, through coalescent simulation, we compare the ability of several popular methods of association mapping to localize causal variants in a sub-region of a candidate genomic region. We consider four broad classes of association methods, which we describe as single-variant, pooled-variant, joint-modelling and tree-based, under an additive genetic-risk model. We also investigate whether differentiating case sequences based on their carrier status for a causal variant can improve fine-mapping. Our results lend support to the potential of tree-based methods for genetic fine-mapping of disease. In the second project, we develop an R package to dynamically cluster a set of single-nucleotide variant sequences. The resulting partition structures provide important insight into the sequence relatedness. In the third project, we investigate the ability of methods based on sequence relatedness to fine-map rare causal variants and compare it to genotypic association methods. Since the true gene genealogy is unknown in reality, we apply the methods developed in the second project to estimate the sequence relatedness. We also pursue the idea of reclassifying case sequences into their carrier status using the idea of genealogical nearest neighbours. We find that method based on sequence relatedness is competitive for fine-mapping rare causal variants. We propose some general recommendations for fine-mapping rare variants in case-control association studies.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Jinko Graham
Department: 
Science: Department of Statistics and Actuarial Science
Thesis type: 
(Thesis) Ph.D.

‘Till long-term care do we part’: Exploring the impacts of separating married couples on couplehood and well-being

Author: 
Date created: 
2021-07-30
Abstract: 

This capstone project explores the impact of separating married couples when one spouse has dementia in long-term care settings. In particular, on couples’ abilities to maintain a sense of couplehood within the socio-physical environment of long-term care and its impacts on each spouse's health and wellbeing. The theoretical perspectives of attachment theory and person-environment exchange are utilized to guide this project, providing a holistic and insightful approach to investigating spousal relationships in long-term care. The goals of this project are two-fold. First, a scoping review of the limited literature will be presented. Second, based on the Canadian Institute of Health Research (CIHR) Project Grant guidelines, a mock grant proposal was developed. The purpose of the grant is to critically examine the institutional practice of separating married couples in LTC settings in British Columbia when one spouse lives with dementia and requires more complex care and support. The proposed study will focus on couples' abilities and challenges in maintaining their relationship within the LTC environment and the effects of separation on their health and wellbeing. Overall, this capstone project will help guide future research, practice, and policy in this important yet understudied topic in gerontology.

Document type: 
Graduating extended essay / Research project
Supervisor(s): 
Barbara Mitchell
Department: 
Arts & Social Sciences: Department of Gerontology
Thesis type: 
(Project) M.A.

Knowing the land as home and alive: Re-centering Snuneymuxw’s relationship to Saysutshun in co-management

Author: 
Date created: 
2021-07-15
Abstract: 

The overall goal of this thesis is to center ways Snuneymuxw First Nation (SFN) have known how to live collaboratively and collectively with their territory since time immemorial. This project looks specifically at the co-management of Saysutshun (Newcastle Island Provincial Marine Park) between SFN, BC Parks, and the City of Nanaimo. Co-management has been a strategy used by Indigenous peoples, including Snuneymuxw, to disrupt the power of the colonial state and reclaim aspects of self-determination. However, co-management structures often become another way the state maintains control over land and decision-making. Based in Indigenous methodologies described by Linda Tuhiwai Smith, anthropological policy and document analysis, and interviews Snuneymuxw, this thesis finds that there is a need to move beyond colonially-centered co-management and to re-centre Indigenous processes and institutions.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Pamela Stern
Department: 
Arts & Social Sciences: Department of Sociology and Anthropology
Thesis type: 
(Thesis) M.A.

Impact of individual-level characteristics on perceptions of problematic sexual encounters

Author: 
Date created: 
2021-07-19
Abstract: 

Rates of sexual assault remain high across university settings despite increased efforts to combat this phenomenon. This project fills a gap in the existing literature by examining how situation-specific variables (i.e. alcohol consumption by and degree of familiarity between individuals) and individual-level factors (i.e., attitudes regarding sexual instrumentality and permissiveness, rape myths, trait token resistance, history of sexual victimization and sexual perpetration) relate to ongoing third-party perceptions of a sexual scenario. The current study used a vignette methodology to portray the dynamic nature of a sexual interaction between a man and a woman that began innocently but escalated to problematic behavior by the man and finally to sexual assault. At eight points in the interaction, a sample of university students (n = 350) reported their perceptions of comfort, safety, consent, and reportability of scenario. They further indicated the extent to which the scenario represented instances of sexual harassment, sexual assault, and state-based female token resistance. As the vignette’s sexual interaction became increasingly problematic, participants reported declining perceptions of comfort, safety, and state-based female token resistance, and they were more likely to characterize the interaction as lacking consent, being worthy of reporting, and involving sexual harassment and sexual assault. An analysis of situational variables within the vignette revealed no significant associations between vignette perceptions and alcohol consumption by or degree of familiarity between characters. For individual-level factors, lower rape myth acceptance was associated with identifying the interaction as lacking consent, being worthy of reporting, and as both sexual harassment and sexual assault. Trait token resistance was also related to perceptions of comfort, safety, and state-based female token resistance. These findings add to the growing literature on university sexual assault by demonstrating that third-party perceptions of sexually problematic vignettes manifest differentially among participants based on individual-level factors but not situational variables.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Stephen D. Hart
Department: 
Arts & Social Sciences: Department of Psychology
Thesis type: 
(Thesis) Ph.D.

Fannish healing and “the tentative step forward”: Musical affect and parasocial directionalities in BTS fan narratives

Author: 
Date created: 
2021-07-13
Abstract: 

Situating itself within the frameworks of musical affect and relational labour, this research examines the healing practices of BTS fans from all around the world. As the biggest Korean musical act to enter the global stage to date, BTS as a group have fostered a unique iteration of the parasocial relationship with their fans and, in doing so, redefined the structures and potentials of the fan-artist relationship. Both through their music and public image, the resulting expansion has allowed fans to create individual networks for affective healing. The purpose of this research is then to establish relational networks as a conceptualization of fannish healing as it is transformed and reappropriated into the lives of individual fans.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Dal Yong Jin
Department: 
Communication, Art & Technology: School of Communication
Thesis type: 
(Thesis) M.A.

Transnational feminist analysis of intimate partner violence in South Asia: A scoping review

Author: 
Date created: 
2021-08-11
Abstract: 

Intimate Partner Violence (IPV) has been recognized as a global public health concern affecting millions of people across the world. Women in South Asian countries of India, Pakistan, Sri Lanka and Bangladesh are increasingly vulnerable to physical, sexual, and emotional abuse. The purpose of this study is to conduct a scoping review of the literature on the available interventions and support systems provided to survivors of IPV through a Transnational Feminist lens. This thesis offers a critical and grounded engagement with literature from South Asia that challenges a Western centered understanding of women from ‘Third World’ cultures and underscores the importance of feminist engagement with larger structures that keep women disempowered. This thesis details the search methods, inclusion criteria and the summary of results.12 articles were included for final analysis. Due to the growing epidemic of IPV and the limited literature available on this issue, specifically examining the impact of interventions and support systems on survivors of IPV, the findings of this review support the need for an examination of systemic injustices impacting women and increased collaboration across sectors for a unified response to IPV.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Alanaise Goodwill
Department: 
Education: Faculty of Education
Thesis type: 
(Thesis) M.A.

Design, synthesis and use of chiral pheromone-based probes to study pheromone enantiomer discrimination in the pheromone binding proteins from the gypsy moth, Lymantria dispar

Date created: 
2021-04-15
Abstract: 

The gypsy moth is a widespread and harmful pest causing extensive damage to the Canada’s forest and orchard ecosystems. It uses (+)-disparlure as a sex pheromone. Discovery of the pheromone, including its absolute configuration, has enabled monitoring of gypsy moth populations. Disparlure of low enantiopurity is not attractive to the moths and, for this reason, enantiopure (+)-disparlure has been a synthetic target for many years. To access (+)-disparlure of high enantiopurity we have used a diastereoselective nucleophilic addition reaction with the enantiopure α-chloroaldehyde (2-chlorododecanal) that yields a stereocontrolled access to the 1,2-anti chlorohydrin core. The (+)-disparlure was prepared through a series of transformations that include a Mitsunobu inversion. We have successfully completed the synthesis of (+)-disparlure in 5 steps as compared to Iwaki’s first synthesis in 12 steps and Sharpless’s widely used synthesis in 6 steps. The same approach was used to produce 18-hydroxydisparlure enantiomers, which were coupled to a linker with an alkyne moiety at the end. The alkyne was then coupled to azide-based commercial fluorescent probes, to furnish fluorescent disparlure-based probes for physical studies. The gypsy moth has two different pheromone binding proteins, LdisPBP1 and LdisPBP2. Previously, our group has addressed the enantiomer selectivity of these two PBPs and found that PBP1 binds (-)-disparlure more strongly than (+)-disparlure, while PBP2 binds (+)-disparlure more strongly. Despite several binding assays, the interaction and discrimination of gypsy moth PBPs towards disparlure enantiomers are not fully understood due to lack of binding interaction and kinetic studies, which are technically demanding, due to the hydrophobicity of the pheromone. In this thesis, we have studied the binding interaction of deuterium-labelled (+)-disparlure and (-)-disparlure with LdisPBPs by 2H NMR spectroscopy. The results from NMR studies were correlated with the results from docking simulations of (+)-disparlure and (-)-disparlure bound to one internal site and multiple external sites of LdisPBP1 and LdisPBP2. These results indicated that (+)-disparlure and (-)-disparlure adopt different conformations and orientations in the binding pockets of LdisPBP1 and LdisPBP2. Most of the reported work on PBPs focuses on the pheromone binding affinities of PBPs. However, the pheromone-PBP interactions require more than half an hour to establish equilibrium, whereas male moths respond to female pheromones in milliseconds. Therefore, the interactions between pheromones and olfactory components such as PBPs and pheromone receptors may not be under thermodynamic control. In this thesis, we aimed to provide a dynamic perspective of pheromone-PBP interactions and to link these to the functions of PBPs. We have studied thermodynamic (Kd) and kinetic properties (kon and koff) of LdisPBPs-disparlure enantiomer interaction by fluorescence binding assays and kinetic experiments using fluorophore-tagged disparlure enantiomers. The result indicated that the binding preference of disparlure enantiomers to LdisPBPs. Based on the kinetic data of LdisPBPs with fluorophore-tagged disparlure enantiomers, we propose a kinetic model that includes a two-step binding process. Each of these two steps may contribute to a different function of the LdisPBPs.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Erika Plettner
Department: 
Science: Department of Chemistry
Thesis type: 
(Thesis) Ph.D.

A riparian restoration plan for a construction site on the Brunette River

Author: 
Date created: 
2021-04-21
Abstract: 

Urbanization has altered riparian ecosystems, resulting in the decline of species that depend on them. The Brunette River in the Lower Mainland of British Columbia is no exception; though it currently supports a range of biotas, many of them are at-risk. These impacts are further accentuated by the expansion of the Trans Mountain Pipeline, which will result in the removal of a portion of critical habitat for the endangered Nooksack Dace. In light of the cultural significance of the basin to Kwikwetlem First Nations, the goal of this plan is to improve conditions at the project site post-construction through the establishment of culturally and ecologically important species and the addition of habitat features. I completed soil, vegetation, and water quality surveys to inform my prescriptions. Recommendations include the management of non-native species using manual and mechanical control methods and the planting of a native riparian community that fits within the confines of human infrastructure. A robust monitoring plan is also provided.

Document type: 
Graduating extended essay / Research project
File(s): 
Supervisor(s): 
Shawn Chartrand
Department: 
Environment: Ecological Restoration
Thesis type: 
(Project) M.Sc.