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.

Cancer risk among women living with HIV: Implications for care in the modern cART era

Author: 
Date created: 
2017-06-28
Abstract: 

Following the advent of modern combination antiretroviral therapy (cART) in 1996, a temporal decline was widely observed in AIDS-related morbidity and mortality. In the province of British Columbia (BC), universal provision of cART free-of-charge for people living with HIV (PLHW) has contributed in part to a significant demographic shift, with individuals over 50 years of age comprising over half of all PLHW. In this context there is a need to understand how comorbidities, such as cancer, impact this aging cohort. Within this line of inquiry, it is imperative to look at cancer risk specifically amongst women living with HIV (WLWH). The majority of studies looking at cancer as a co-morbid condition among PLWH fail to conduct sex-stratified analyses, which may obscure the burden of cancer risk specific to WLWH. Using a Life Course Epidemiology framework, the objectives of this PhD dissertation were to: 1) measure cancer incidence among WLWH in BC compared to a general population sample of women; 2) identify the role of early cART initiation in mitigating excess risk of cancer observed among WLWH; and 3) estimate the burden of cancer-related mortality among PLWH. This research utilized administrative health data from Population Data BC (which included data from the BC Cancer Agency and Vital Statistics) and clinical HIV data from the BC Centre for Excellence in HIV/AIDS. Findings suggest WLWH experience an increased risk of certain cancers, notably for certain viral-related malignancies, in comparison to HIV-negative women in the modern cART era. A protective effect of early initiation of cART therapy was found for some types of cancer, suggesting oncological health benefits might be associated with timely initiation of cART after HIV diagnosis for WLWH. Finally, sex stratified age-adjusted cancer-related mortality rates promisingly suggest there may not be significantly different cancer-related mortality outcomes between PLWH and the general population. This dissertation demonstrates that cancer-related morbidity is a healthcare priority for the growing aging demographic of WLWH and subsequently highlights the importance of appropriate and effective routine cancer screening measures as well as comprehensive HIV care inclusive of timely diagnosis and cART initiation.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Robert Hogg
Department: 
Health Sciences: Faculty of Health Sciences
Thesis type: 
(Thesis) Ph.D.

New Food Baits for Trapping German Cockroaches Blattella germanica (L.)

Date created: 
2017-06-27
Abstract: 

New trap baits were designed and tested for attracting German cockroaches (GCRs), Blattella germanica. In large-arena laboratory experiments, traps baited with rye bread captured 8-fold more GCR males than unbaited control traps. Neither beer nor water enhanced the attractiveness of bread. As Porapak Q headspace volatile extracts of rye bread attracted GCRs, all odorants in extracts were identified by gas chromatography-mass spectrometry. A blend of synthetic rye bread odorants and other known bread odorants was highly attractive to GCRs but the essential components in that blend are yet to be determined. In and field trapping experiments, both a 3-component composition (3CC) [dry malt extract (DME), water, Brewer’s yeast] and DME alone were as effective for attracting GCRs as a commercial cockroach bait. Future studies will investigate lethal biocontrol agents that can be added to the 3CC, or the DME, and will explore the efficacy of such baits for GCR control.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Gerhard Gries
Department: 
Science: Biological Sciences Department
Thesis type: 
(Thesis) M.P.M.

Time-resolved gamma-ray spectroscopy with the GEARS detector: Applications in environmental radionuclide monitoring and neutron activation analysis

Date created: 
2017-08-17
Abstract: 

The Simon Fraser University Nuclear Science Laboratory (SFU NSL) joined into two collaborations, each with an interest in monitoring Fukushima-derived cesium-134 and cesium-137 in various environmental samples. The first investigated Fukushima-derived contamination in soil and three species of Pacific salmon, sockeye, chum, and Chinook. The second investigated Fukushima-derived contamination in sockeye salmon, Dungeness crab, and kelp. In both of these monitoring campaigns, the maximum radiocesium activity concentrations observed were significantly below Health Canada's regulatory limits with the conclusion drawn that there is no health risk to the average Canadian seafood consumer. The Neutron Generator Facility at SFU NSL has recently acquired a Thermo Scientific P 385 neutron generator capable of activating samples, inducing radioactivity in them which may be studied via time-resolved gamma-ray spectroscopy. Recording timing information is a prerequisite of these studies therefore, a new data acquisition (DAQ) system was installed with the Germanium detector for Elemental Analysis and Radioactivity Studies enabling timing measurements to take place. The new DAQ system was benchmarked via the measurement of two neutron activated metals, verifying its stability and precision.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Krzysztof Starosta
Department: 
Science: Department of Chemistry
Thesis type: 
(Thesis) M.Sc.

Simulating regional effects of U.S. climate policies with the CIMS-US model

Author: 
Date created: 
2017-08-24
Abstract: 

In this project, I disaggregate the energy-economy model CIMS-US into four United States (U.S.) regions, Midwest, Northeast, South and Pacific/Mountain, to obtain regional resolution for climate policy effects on the electricity generation and transportation sectors. Five policies are modelled to reach climate targets previously set by President Obama: the Clean Power Plan (CPP), a coal and natural gas phase-out regulation, Corporate Average Fuel Economy Standards, and a Vehicle Emission Standard. Lastly, a carbon tax is applied across all sectors in the economy. My results show that Midwest is the most emission-intensive region. Due to the effects of pre-existing California climate policies, Pacific/Mountain experiences the lowest marginal abatement costs to decarbonize its electricity sector. Low marginal abatement costs can induce deeper reductions in full cycle emissions from electricity-powered vehicles. Because of insufficient regional variation in my results, I suggest an alternative disaggregation method.

Document type: 
Graduating extended essay / Research project
File(s): 
Senior supervisor: 
Mark Jaccard
Department: 
Environment: School of Resource and Environmental Management
Thesis type: 
(Research Project) M.R.M.

Sectarianism or geopolitics? Framing the 2011 Syrian conflict

Author: 
Date created: 
2017-08-01
Abstract: 

The Syrian conflict began as an uprising against the Assad regime for political and economic reform. However, as violence escalated between the regime and opposition, the conflict drew in Iran, Turkey, and Saudi Arabia, which backed both the regime and opposition with resources. The current conflict is described as sectarian because of the increasingly antagonistic relations between the Shiite/Alawite regime and the Sunni-dominated opposition. This thesis examines how sectarian identity is politicized by investigating the role of key states during the 2011 Syrian conflict. I argue that the Syrian conflict is not essentially sectarian in nature, but rather a multi-layered conflict driven by national and regional actors through the selective deployment of violence and rhetoric. Using frame analysis, I examine Iranian, Turkish, and Saudi Arabian state media coverage of the Syrian conflict to reveal the respective states’ political position and interest in Syria. Through process tracing, I further identify three causal mechanisms – strategic framing, ethnic/sectarian outbidding, and resource mobilization – to examine how these states catalyzed sectarianism in the Syrian conflict.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Tamir Moustafa
Nicole Jackson
Department: 
Arts and Social Sciences: School for International Studies
Thesis type: 
(Thesis) M.A.

Generating and streaming immersive sports video content

Author: 
Date created: 
2017-08-18
Abstract: 

Stereoscopic 3D videos have already become popular in movie theaters with most productions being released in this format. More recently, with the availability of commodity Virtual Reality (VR) products, immersive video content is receiving even more interest. A wide spread adoption of immersive devices and displays is hindered by the lack of content that matches the user expectations. Producing immersive videos is far more costly and time-consuming than regular 2D videos, which makes it challenging and thus rarely attempted, especially for live events, such as sports games. In addition, immersive content needs to be adapted for viewing on different displays/devices. To address these challenges, we first propose a new system for 3D video streaming that provides automatic depth adjustments as one of its key features. Our system takes into account both the content and the display type in order to customize 3D videos and optimize the viewing experience. Our stereoscopic video streaming system was implemented, deployed and tested with real users. Results show that between 60% to 70% of the shots can benefit from our system and more than 25% depth enhancement can be achieved. Next, we propose a novel, data-driven method that converts 2D videos to 3D by transferring depth information from a database of similar 3D videos. Our method then reconstructs the depth map while ensuring temporal coherency using a spatio-temporal formulation of Poisson reconstruction. Results show that our method produces high-quality 3D videos that are almost indistinguishable from videos shot by stereo cameras, while achieving up to 20% improvement in the perceived depth compared to the current state-of-the-art method. Furthermore, we extend our work in the direction of VR, and propose using video feeds from regular broadcasting cameras to generate sports VR content. We generate a wide-angle panorama by utilizing the motion of the main camera. We then use various techniques to remove the parallax, align all video feeds, and overlay them on the panorama. Subjective studies show that our generated content provides an immersive experience similar to ground-truth content captured using a 360 camera, with most subjects rating their sense of presence from Good to Excellent.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Mohamed Hefeeda
Department: 
Applied Sciences: School of Computing Science
Thesis type: 
(Thesis) Ph.D.

Distributions of Time to First Spot Fire

Author: 
Date created: 
2017-08-15
Abstract: 

In wildfire management, a spot fire is the result of an airborne ember igniting a separate fire away from the main wildfire. Under certain environmental and wildfire conditions, a burning ember can breach a fuel break, such as a river or road, and result in the production of a spot fire. This project derives distributions of the time to the first spot fire in various situations, and verifies them by simulation. To demonstrate the implementation of the distributions in practice, we incorporate a stochastic fire spread model. This research assesses the likelihood of spot fire occurring passed a fuel break, all while taking into account both spotting distance and spotting rate. This contrasts with the traditional approach that solely involves the maximal spotting distance, and can be a tool for fire management.

Document type: 
Graduating extended essay / Research project
File(s): 
Senior supervisor: 
Joan Hu
Department: 
Science: Department of Statistics and Actuarial Science
Thesis type: 
(Project) M.Sc.

Exploring Parents’ Perceptions of Student Absenteeism in K-3

Date created: 
2017-08-21
Abstract: 

Chronic absenteeism affects students’ academic achievement as well as their social and emotional wellbeing. In early elementary school, the primary responsibility for school attendance rests with parents and guardians. This thesis investigates parents’ perceptions of factors related to school attendance. The study was conducted in BC’s largest school district within the context of an absenteeism reduction program. Fifty-four parents of students in K-3 from 15 inner-city schools participated in individual interviews that explored their views on the links between the purpose of school, attendance, and academic achievement. While most parents’ perceptions were that attendance is important providing social and academic value, several noted that they kept their child at home to bond with a parent or to support their children's mental health. The results point to a complex and nuanced relationship among factors linked to school attendance, such as individual child and parent characteristics, transportation, food security, and after- school programs.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Michelle Nilson
Department: 
Education: Faculty of Education
Thesis type: 
(Thesis) M.A.

The Professional Learning Experiences of Non-Mathematics Subject Specialist Teachers: A Descriptive Study

Date created: 
2017-08-17
Abstract: 

Certified teachers in British Columbia (BC) schools can be assigned to teach secondary mathematics without having a major, minor, or formal background in mathematics. This is known as out-of-field teaching. These non-mathematics subject specialist teachers (NMSSTs) must learn or relearn the subject matter of mathematics to teach secondary mathematics. This study investigates what professional learning activities NMSSTs participate in to gain subject matter content knowledge in mathematics, which activities these teachers believed best facilitated the acquisition of subject matter, and which they believed helped them to teach secondary mathematics better. This was a descriptive study using survey methods. Sixteen professional learning activities were considered. The survey questionnaire was distributed and completed online. Sixty-two NMSSTs completed the survey in full. Most learned the subject matter autodidactically from teaching secondary mathematics, referring to textbooks, or going online. However, formal learning activities such as completing a graduate degree in mathematics or a mathematics-related field best facilitated the acquisition of the subject matter and helped in teaching mathematics better. Other findings include the following: learning from an expert in the field was highly valued; professional learning days were not highly valued but frequently participated-in; the perceived level of subject matter content knowledge of those who completed a graduate degree and those who did not were the same; the NMSST characteristic of perceived level of subject matter content knowledge did not influence participants in this study to self-identify as mathematics subject specialists. Recommendations for practitioners included not learning the subject matter in isolation and to find a mentor. Recommendations for school leaders were to redesign professional development days and to consider purposeful teaching assignments. Recommendations for future research were to develop a self-assessment tool and to implement a study on subject matter acquisition of NMSSTs in a master of mathematics education program. Recommendations for policy-makers included providing alternative professional development opportunities for teachers and setting standards for NMSSTs to help them self-assess their subject matter content knowledge in mathematics.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Daniel Laitsch
Department: 
Education: Faculty of Education
Thesis type: 
(Thesis) Ed.D.

Stability in stochastic language change models

Date created: 
2017-07-24
Abstract: 

Exemplar models are a popular class of models used to describe language change. Exemplars are detailed memories of stimuli people are exposed to, and when modelling language change are represented as vectors where each component is a phonetic variable. Each exemplar is given a category label, representing what that sound is identified as. New sounds are categorized based on how close they are to the exemplars in each category. Newly categorized exemplars become a part of the system and affect how the future sounds are produced and perceived. It is possible in certain situations in language for a category of sound to become extinct, such as a pronunciation of a word. One of the successes of exemplar models has been to model extinction of sound categories. The focus of this dissertation will be to determine whether categories become extinct in certain exemplar models and why. The first model we look at is an exemplar model which is an altered version of a k-means clustering algorithm by MacQueen. It models how the category regions in phonetic space vary over time among a population of language users. For this particular model, we show that the categories of sound will not become extinct: all categories will be maintained in the system for all time. Furthermore, we show that the boundaries between category regions fluctuate and we quantitatively study the fluctuations in a simple instance of the model. The second model we study is a simple exemplar model which can be used to model direct competition between categories of sound. Our aim in investigating this model is to determine how limiting the memory capacity of an individual in exemplar models affects whether categories become extinct. We will prove for this model that all the sound categories but one will always become extinct, whether memory storage is limited or not. Lastly, we create a new model that implements a bias which helps align all the categories in the phonetic space, using the framework of an earlier exemplar model. We make an argument that this exemplar model does not have category extinction.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Paul Tupper
Department: 
Science: Department of Mathematics
Thesis type: 
(Thesis) Ph.D.