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.

Combinatorial methods for integer partitions

Author: 
Date created: 
2021-08-20
Abstract: 

Integer partitions, while simply defined, are associated with some of the most celebrated results in mathematics. Despite their simple definition, many results on integer partitions can be shockingly difficult to obtain. In this thesis, we use elementary and combinatorial methods to make progress on some fundamental problems related to linear Diophantine equations and integer partitions. We find an efficient method for finding the number of nonnegative integer solutions (x,y,z) of the equation ax+by+cz=n for given positive integers a, b, c, and n. Our formula involves summations of floor functions of fractions. To quickly evaluate these sums, we find a reciprocity relation that generalizes a well-known reciprocity relation of Gauss related to the law of quadratic reciprocity. Furthermore, we use our result for the number of solutions to a particular equation to prove that the above result of Gauss is equivalent to a well-known result of Sylvester related to the Frobenius Coin Problem. Moreover, using this equivalence and our generalization of the reciprocity relation of Gauss, we obtain a nice generalization of Sylvester's result. In a different problem, we prove four conjectures of Berkovich and Uncu regarding some inequalities about relative sizes of two closely related sets consisting of integer partitions whose parts lie in the interval {s,...,L+s}. Further restrictions are placed on the sets by specifying impermissible parts as well as a minimum part. Our methods consist of constructing injective maps between the relevant sets of partitions. We obtain a very natural combinatorial proof of Euler's recurrence for integer partitions using the principle of inclusion and exclusion. Using our approach, we are able to generalize Euler's recurrence in the sense that for sufficiently large n, we can express p(n) explicitly as an integer linear combination of p(n-k), p(n-k-1),... etc. Using such recurrences, we obtain results related to Ramanujan's congruences. For example, if p_m(n) denotes the number of partitions of n that have largest part at most m, we show that for m > 5, the numbers p_m(5n+4) are not divisible by 5 for infinitely many values of n.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Amarpreet Rattan
Department: 
Science: Department of Mathematics
Thesis type: 
(Thesis) Ph.D.

Discovery and characterization of novel non-coding 3′ UTR mutations in NFKBIZ and their functional implications in diffuse large B-cell lymphoma

Author: 
Date created: 
2021-08-16
Abstract: 

Diffuse large B-cell lymphoma (DLBCL) is a very heterogenous disease that has historically been divided into two subtypes driven by distinct molecular mechanisms. The activated B-cell (ABC) subtype of DLBCL has the worst overall survival and is characterized by activation of the NF-κB signaling pathway. Although many genetic alterations have been identified in DLBCL, there remain cases with few or no known genetic drivers. This suggests that there are still novel drivers of DLBCL yet to be discovered. In this thesis I aimed to leverage whole genome sequencing data to identify novel regions of the genome that were recurrently mutated, with a specific focus on non-coding regions. Through this analysis we identified numerous novel putative driver mutations within the non-coding genome. One of the most highly recurrently mutated regions was in the 3′ untranslated region (UTR) of the NFKBIZ gene. Amplifications of this gene have been previously discovered in ABC DLBCL and this gene is known to activate NF-κB signaling. Therefore, we hypothesized that these 3′ UTR mutations were acting as drivers in DLBCL. The remaining portion of this thesis is focused on the functional characterization of NFKBIZ 3′ UTR mutations and how they drive DLBCL and contribute to treatment resistance. To this end, I induced NFKBIZ 3′ UTR mutations into DLBCL cell lines and determined that they cause both elevated mRNA and protein expression. These mutations conferred a selective growth advantage to DLBCL cell lines both in vitro and in vivo and overexpression of NFKBIZ in primary germinal center B-cells also provided cells a growth advantage. Lastly, I found that NFKBIZ-mutant cell lines were more resistant to a selection of targeted therapeutics (ibrutinib, idelalisib and masitinib). Taken together, this thesis highlights the importance of surveying the entire cancer genome, including non-coding regions, when searching for novel drivers. I demonstrated that mutations in the 3′ UTR of a gene can act as driver mutations conferring cell growth advantages and treatment resistance. This work also implicates NFKBIZ 3′ UTR mutations as potentially useful biomarkers for predicting treatment response and informing on the most effective treatment options for patients.

Document type: 
Thesis
Supervisor(s): 
Ryan Morin
Department: 
Science: Department of Molecular Biology and Biochemistry
Thesis type: 
(Thesis) Ph.D.

Multi-omics characterization of pancreatic neuroendocrine neoplasms

Author: 
Date created: 
2021-08-18
Abstract: 

Pancreatic neuroendocrine neoplasms (PNENs) are biologically and clinically heterogeneous neoplasms in which pathogenic alterations are often indiscernible. Treatments for PNENs are insufficient in part due to lack of alternatives once current options are exhausted. Despite previous efforts to characterize PNENs at the molecular level, there remains a lack of molecular subgroups and molecular features with clinical utility for PNENs. In this work, I describe the identification and characterization of four molecularly distinct subgroups from primary PNEN specimens using whole-exome sequencing, RNA-sequencing and global proteome profiling. A Proliferative subgroup with molecular features of proliferating cells was associated with an inferior overall survival probability. A PDX1-high subgroup consisted of PNENs demonstrating genetic and transcriptomic indications of NRAS or HRAS activation. An Alpha cell-like subgroup, enriched in PNENs with deleterious MEN1 and DAXX mutations, bore transcriptomic similarity to pancreatic α-cells and harbored proteomic cues of dysregulated metabolism involving glutamine and arginine. Lastly, a Stromal/Mesenchymal subgroup exhibited increased expression and activation of the Hippo signaling pathway effectors YAP1 and WWTR1 that are of emerging interest as potentially actionable targets in other cancer types. Whole-genome and whole-transcriptome analysis of PNEN metastases identified novel molecular events likely contributing to pathogenesis, including one case presumably driven by MYCN amplification. In agreement with the findings in primary PNENs, four of the metastatic PNENs displayed a substantial Alpha cell-like subgroup signature and all harboured concurrent mutations in MEN1 and DAXX. Collectively, the identified subgroups present a potential stratification scheme that facilitates the identification of therapeutic vulnerabilities amidst PNEN heterogeneity to improve the effective management of PNENs.

Document type: 
Thesis
Supervisor(s): 
Sharon Gorski
Department: 
Science: Department of Molecular Biology and Biochemistry
Thesis type: 
(Thesis) Ph.D.

Profiling the University of British Columbia Doctor of Medicine undergraduate students’ physical activity knowledge, attitudes, and health behaviours

Author: 
Date created: 
2021-07-29
Abstract: 

The growing Exercise is Medicine (EIM) initiative recommends that physicians assess and prescribe physical activity as part of their patient care to tackle the physical inactivity public health crisis (Sallis, 2009). The purpose of this study was to investigate whether University of British Columbia (UBC) Doctor of Medicine (MD) students have the physical activity related knowledge, attitudes, and health behaviours to include physical activity when prescribing treatment plans for their patients and whether the knowledge, attitudes, and behaviours differ between years of the medical program. In a cross-sectional design, an online survey was administered to profile the UBC MD student population and investigate variables addressing the research questions. Statistics were used to examine frequency distributions, measures of central tendency, and any significant (P < 0.05) differences between years of the medical program. The response rate was 18.9% (217/1150). Mean age (SD) of participants was 25.5 (3.9) years and the majority were female (60.7%), white (58.1%), single (72.9%), first year (41.6%), and from Vancouver Fraser (61.1%). The main findings were: 90.3% were aware of the Canadian Physical Activity Guidelines for Adults, but their understanding was poor; 78.8% recalled seven hours or less time spent discussing physical activity, and 74.4% would like to see more time dedicated to learning how to talk to their patients about physical activity; 98.0% strongly agreed or agreed that physical activity counselling is important, only 57.0% felt they have sufficient knowledge, and only 36.6% felt confident in suggesting specific physical activity programs; 96.0% felt medical schools should encourage healthy lifestyles, but only 49.0% felt they do; 89.8% reported their health as excellent or good, but 29.5% identified as having mental health concerns; 76.8% were meeting Canadian Physical Activity Guidelines, and the mean (SD) Godin Leisure Time Exercise Score was 55.6 (25.4) which is a classification of Active. Participants were receptive to an EIM approach to increase physical activity levels and health outcomes of the population. Given the lack of necessary knowledge, training, and confidence to support EIM in clinical practice, recommendations for medical education, policy, and practice are provided to better equip medical students to positively impact global health.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Scott Lear
Department: 
Education: Faculty of Education
Thesis type: 
(Thesis) Ed.D.

Procedural justice and the police's use of personal protective equipment during the COVID-19 pandemic

Author: 
Date created: 
2021-07-20
Abstract: 

The COVID-19 pandemic has resulted in new responsibilities for police while also introducing new accoutrements by way of personal protective equipment (PPE). This thesis examines the effects of such changes and the role of procedural justice as it relates to public assessments of police and willingness to cooperate with police during the pandemic. As part of the thesis, participants rated images of a police officer using different items of PPE on the dimensions of procedural justice and then answered survey questions about the police more broadly. The findings indicate that participants’ perceptions of procedural justice are positively related to their assessments of police and willingness to cooperate with police. The findings also indicate that participants’ perceptions of procedural justice can be impacted by the police’s use of PPE. The thesis discusses the important practical implications of such findings for police who must continue to manage public perceptions while providing service.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Rylan Simpson
Department: 
Arts & Social Sciences: School of Criminology
Thesis type: 
(Thesis) M.A.

Examining the effects of activator compounds on hERG cardiac potassium channel protective currents conducted in response to premature stimulations

Author: 
Date created: 
2020-08-05
Abstract: 

The human ether-a-go-go-related gene (hERG) encodes the rapid delayed rectifier cardiac potassium channel. Vital for repolarization of the myocardium and termination of the cardiac action potential, loss of function in hERG K+ channels can result in Long QT Syndrome Type II (LQTS2). Additionally, hERG channels have been shown to mediate robust repolarizing currents in response to premature depolarizations, reflective of channels remaining in the open state into the refractory period. Thought to be protective against afterdepolarizations, loss of function in this regard may leave individuals susceptible to arrhythmia. Recently, several small molecule activators of hERG have been discovered. The effects of these compounds on the protective currents mediated by hERG channels have yet to be studied. The work presented in this thesis examines the effects of both Type I and II hERG channel activators on protective currents mediated by hERG channels, in the context of an inherited mutation.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Tom Claydon
Department: 
Science: Department of Biomedical Physiology and Kinesiology
Thesis type: 
(Thesis) M.Sc.

Audio beacon technologies, surveillance and social order

Date created: 
2021-07-22
Abstract: 

This thesis explores audio beacon technology with the aim of elucidating the implications of this technology for the individual in contemporary society. Audio beacons are hidden inside digital devices. They emit and receive high frequency audio signals which are inaudible to the human ear, thereby generating and transmitting data without our knowledge. The motivation for this research is to raise awareness of the prevalence of audio beacon technologies and to explore their implications for contemporary society. The research takes an interdisciplinary approach involving – 1) a survey of audio beacon technology, 2) a contextualization in terms of contemporary theories of surveillance and control and 3) an interpretation in terms of 20th century dystopian literature. The hidden surveillance and privacy of this technology is examined mainly through the humanistic perspective of George Orwell’s book Nineteen Eighty-Four. The general conclusion formed is that audio beacon technologies can serve as a surveillance method enhancing authoritarian and exploitative regimes. To mitigate the negative impacts of audio beacons, this research proposes two types of solutions – 1) individual actions that will have an immediate effect and 2) governmental legislation that can improve privacy in the longer term. Both of these solutions cannot happen without a raised public awareness, towards which this research hopes to make a contribution. Finally, this research introduces the notion of a 'digital paradox' in which the dystopian worlds of George Orwell and Aldous Huxley are brought together in order to characterize surveillance and control in contemporary society.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Niranjan Rajah
Department: 
Communication, Art & Technology: School of Interactive Arts and Technology
Thesis type: 
(Thesis) M.A.

Development of chemical tools for the study of intracellular glycosylation

Author: 
Date created: 
2020-06-04
Abstract: 

Intracellular protein O-glycosylation is an important post-translational modification in mammalian cells with critical regulatory functions relating to transcription, stress response, cell signalling, and cell cycle control. This process is controlled by two enzymes: O-GlcNAc transferase (OGT), which catalyzes the addition of a single O-linked N-acetylglucosamine (O-GlcNAc) to serine and threonine residues of proteins, and O-GlcNAcase (OGA), which hydrolyzes the glycosidic linkage on proteins. While notable progress has been made in the design and application of chemical tools for the study of OGA, methods and tool compounds to detect and modulate the activity of OGT remain limited. In this thesis, I describe the development of a fluorescent glycosyl donor analogue which is tolerated by OGT and transferred to peptides and proteins. This substrate was exploited to develop a convenient and direct in vitro activity assay, enabling the study of OGT catalysis in the presence of various substrates and inhibitors. After optimizing the assay for high-throughput screening, a collection of small molecule libraries encompassing approximately 64,000 compounds was screened, leading to the identification of a novel and selective inhibitor of OGT. This assay was further applied to the functional analysis of peptide-based inhibitors of OGT that were discovered through phage display and in vitro mRNA display technologies. These efforts enabled the development of chemical tools with potent nanomolar affinity for OGT. The in vitro assay was also used for the study of novel glycosylation activity by OGT towards cysteine-containing acceptor substrates, permitting a detailed kinetic analysis of this recently discovered phenomenon. Finally, I describe the biochemical characterization of human Hexosaminidase D (HexD), an intracellular glycoside hydrolase of unknown physiological function, and use this information in the design of potential selective inhibitors. The methods, results, and insights gained from this research should prove useful in advancing our understanding of intracellular glycosylation and for furthering the application of this knowledge for translational therapeutic benefit.

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

Control system development for energy-efficient lighting in greenhouses

Author: 
Date created: 
2020-08-20
Abstract: 

This thesis focuses on the development and implementation of feedback control with application to an energy-efficient lighting system for potential application in a greenhouse environment. The proposed control system was developed and implemented in four stages. First, the lighting model for the red and blue lights was identified separately to ensure uniform light distribution at plant canopies. Subsequently, a daylight environment was constructed using the MATLAB/Simulink environment. The performance of the system was evaluated on a proof of concept system through a series of simulations to verify the control performance. In the second stage, the proposed concept was implemented to regulate the intensity of dimmable multi-spectrum LED fixtures for achieving desired spectral irradiance levels and color ratios while utilizing daylight harvesting to enhance energy-efficiency. To ensure the stability and performance, a Smith predictor was utilized to compensate for the delay introduced into the system by the communication hardware. Implementation of the proposed system with a smooth transient response ensured lower energy consumption for the LED panels. In the third stage, a testbed with environment monitoring and intelligent LED lighting control system was implemented with potential utilization in an Internet of Things (IoT) smart greenhouse environment. The performance of the LED control system was verified through conducting plant experiments in the proposed testbed. It was shown that the proposed testbed is capable of achieving the desired light requirement for the tested plant while maintaining satisfactory plant growth results. Finally, in the fourth stage, the proposed concept was extended to a small-scale plant growth and implemented on a Raspbian operating system with the IoT technology. The system was utilized to implement lighting control and environmental monitoring applications for greenhouses in remote areas. Results show potential for prominent energy savings when the proposed lighting system is utilized to grow kale microgreens, which further resulted in improved plant quality due to uniform lighting conditions achieved through feedback control.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Mehrdad Moallem
Jason Wang
Department: 
Applied Sciences: School of Mechatronic Systems Engineering
Thesis type: 
(Thesis) Ph.D.

Social media and GIScience: Collection, analysis, and visualization of user-generated spatial data

Author: 
Date created: 
2021-06-21
Abstract: 

Over the last decade, social media platforms have eclipsed the height of popular culture and communication technology, which, in combination with widespread access to GIS-enabled hardware (i.e. mobile phones), has resulted in the continuous creation of massive amounts of user-generated spatial data. This thesis explores how social media data have been utilized in GIS research and provides a commentary on the impacts of this next iteration of technological change with respect to GIScience. First, the roots of GIS technology are traced to set the stage for the examination of social media as a technological catalyst for change in GIScience. Next, a scoping review is conducted to gather and synthesize a summary of methods used to collect, analyze, and visualize this data. Finally, a case study exploring the spatio-temporality of crowdfunding behaviours in Canada during the COVID-19 pandemic is presented to demonstrate the utility of social media data in spatial research.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Nadine Schuurman
Department: 
Environment: Department of Geography
Thesis type: 
(Thesis) M.Sc.