title: Frequency Domain Modelling & Design of an LCC Resonant Converter with Capacitive Output Filter

contributor:
Jain, Praveen
Electrical and Computer Engineering

subject:
Resonant Converter
Series Parallel
Zero Voltage Switching
Frequency Domain Modelling
Capacitive Output Filter

abstract: Resonant DC-DC converters have been widely discussed with one of the most popular being the LCC topology. It’s application towards low to high voltage converters warrants the use of a capacitive output filter to limit the voltage stress on the rectifier. Designs with a high quality factor (Q) suffer from large resonant component sizes and stresses leading to power losses in the magnetic components. It is then desirable to design a low Q converter to minimize these stresses for compactness and efficiency. Previous time domain analysis shows the converter predominantly operates in one mode so a frequency domain analysis was possible. Due to the voltage charging and clamping action of the parallel resonant capacitor as a result of the capacitive output filter, enhanced fundamental harmonic approximation (FHA) models were used to analyze this topology. These were accurate for high Q designs with approximately sinusoidal waveforms but degraded for light load, low Q conditions. In this thesis, a frequency domain model considering higher order harmonics is presented for the LCC resonant converter with a capacitive output filter. This general model applies to the study of the converter under variable frequency and phase shift modulation control techniques. Converter characteristics can be studied using the provided generalized curves of voltage gain (Vo / Vi), phase shift (ϕ), and non-conduction angle (θ). Using the nth harmonic equivalent circuit, steady state performance is easily obtained. The model is verified against a 380V, 250W experimental prototype with 22-44V input and the commercial simulation software PSIM.  A simple design procedure is detailed focusing on low Q designs helping minimize the stress and size of the resonant components. An optimal parallel to series capacitance ratio (k) and Q selection helps reduce conduction and magnetic losses of the converter.

abstract: M.A.Sc.


title: Investigating Potential Bi-directional Relationships Between Sleep and Melatonin Among Day and Rotating Day/Night Shift Workers

contributor:
Aronson, Kristan J.
Tranmer, Joan
Public Health Sciences

rights: Queen's University's Thesis/Dissertation Non-Exclusive License for Deposit to QSpace and Library and Archives Canada

rights: ProQuest PhD and Master's Theses International Dissemination Agreement

rights: Intellectual Property Guidelines at Queen's University

rights: This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.

subject:
Sleep
Melatonin
Bi-Directional
Shift Work

abstract:
Objectives: The first objective of this study is to describe measures of sleep in day and rotating shift workers. The second objective is to assess the bi-directional relationships between sleep and melatonin among: 1) female hospital day workers; and, 2) female rotating day/night shift workers, in two models:  Model A includes the assessment of sleep on work days on melatonin the following day and Model B includes the assessment of melatonin on work days on sleep the following day.  These models were determined in a stratified analysis based on shift work status and cumulative shift work duration in years.
Methods:  In a cross-sectional study of female hospital employees (n=266), sleep parameters  were collected using Actical® accelerometers and assessed using the Cole-Kripke algorithm. Urinary 6-sulfatoxymelatonin concentrations were collected over 24 hours and examined using cosinor analysis to obtain average concentrations (mesor) and time of peak concentration (acrophase time). All relationships were analyzed using multiple linear regression.
Results: Day workers slept about seven hours per night in both temporal models, whereas rotating workers slept less than seven hours between two night shifts and more than seven hours following their second night shift. When sleep precedes melatonin, for every hour increase in main sleep time, a 13-minute decrease in melatonin acrophase time was observed among rotating shift workers (95% CI: -26.5– -0.3). Effect modification by cumulative shift work duration (< 10 years vs. ≥ 10 years) was apparent in the relationship between main sleep time and mesor for the time period of Model A (p-value for interaction = 0.02). There were weak associations with sleep latency in both models.
Conclusion: In comparison to day workers, rotating shift workers were more likely to not meet the recommended seven hours of sleep per night over the two temporal periods of interest, which is a public health concern. Sleep and melatonin may be related temporally in both directions in the relationship between main sleep time and melatonin acrophase time. The effect of sleep duration on melatonin may depend on the total length of exposure to shift work and not on current day or rotating shift status.

abstract: M.Sc.


title: Hypoxia Inhibits Kv1.5 Currents Through Reactive Oxygen Species-Mediated Post Translational Cysteine Modification

contributor:
Zhang, Shetuan
Biomedical and Molecular Sciences

subject: Kv1.5

subject: ROS

subject: Reactive Oxygen Species

subject: AF

subject: Atrial Fibrillation

subject: Ultra-Rapid Delayed Rectifier Potassium Current

subject: HEK

abstract: The voltage-gated potassium channel Kv1.5 plays an important role in atrial repolarization and vascular tone of pulmonary arteries. Dysfunction of Kv1.5 channels can lead to atrial fibrillation and pulmonary hypertension, both of which are associated with hypoxia. In the present study, we investigated the effects of hypoxia on Kv1.5 channels. We induced hypoxia by culturing Kv1.5-expressing HEK 293 cells and neonatal rat ventricular myocytes in hypoxic conditions (0.5% O2) and then recorded Kv1.5 current using whole-cell voltage clamp. We observed that 3 hours of hypoxic culture reduced current after 3 hours. Using immunofluorescent staining and western blot analysis, we found that hypoxic culture-induced decrease in current was not caused by the internalization of mature Kv1.5 channels from the membrane. However, we found that hypoxia-induced current reduction is mediated through reactive oxygen species (ROS). First, hydrogen peroxide (H2O2) treatment decreased current in a manner similar to hypoxic culture. Second, the addition of dithiothreitol (DTT), a reducing agent, abolished the effects of hypoxia-induced current reduction. Therefore, our results demonstrate that disrupting ROS-mediated posttranslational modification abolishes the hypoxia-induced reduction in Kv1.5 current. Furthermore, hypoxia-induced reduction in Kv1.5 current required specific cysteine residues within the Kv1.5 channel; using point mutations, our results showed that mutation of Cys581 abolished hypoxia-induced current reduction. Therefore, we have demonstrated that hypoxia decreases IKv1.5 through the production of ROS and that the subsequent posttranslational modifications involve Cys581.

abstract: M.Sc.


title: Best Practices When Using Multi-Rotor Consumer UAVs for Photogrammetric Mapping: Limitations and Possible Solutions

contributor:
Chen, DongMei
Bevan, George
Geography and Planning

subject:
UAV
Photogrammetry
Remote Sensing
Camera Calibration
Maltese-Cross Camera Network
Flight Planning

abstract: Photogrammetry has seen great technological advancements since its inception almost 150 years ago. Today digital cameras are being mounted to unmanned aerial vehicles (UAVs) and used for aerial surveying and photogrammetry. Within the past decade, consumer-grade multi-rotor UAVs have become viable platforms for performing low altitude aerial photogrammetry. Modern-day photogrammetric software has become so advanced that processing requires minimal intervention for the user to produce results. Although performing low altitude aerial photogrammetry can achieve a high ground sample distance, at these low altitudes, artifacts and inadequacies begin to appear within produced digital surface models and orthophotos. Additionally, many flight plan and post-processing software packages limit or even hide features that prevent users from fully taking advantage of photogrammetric practices and the capabilities of consumer multi-rotor UAVs. In this study, through the modification of flight plan CSV files, several different methods are explored to re-introduce photogrammetric practices to the multi-rotor UAV platform in an attempt to improve the production of digital surface models and orthophotos. Flight plans are modified to allow for images to be captured in portrait orientation using a fixed camera to achieve an improved project depth accuracy. By further modifying flight plan CSV files, automated aerial camera calibration flight plans are created while incorporating traditional terrestrial calibration techniques. The use of an automated camera pre-calibration flight plan is found to outperform auto-calibration workflows. Lastly, with the ability to modify a flight plans CSV file, the Maltese-cross camera network is simulated using a single camera onboard a consumer-grade multi-rotor UAV to achieve simultaneous horizontal and vertical mapping at low altitude. These approaches combine to allow for improved data acquisition and post-processing when using consumer-grade multi-rotor UAVs to produce high-quality digital surface models and orthophotos. Improving these photogrammetric products allows for users to take full advantage of the features of consumer multi-rotor UAVs while ensuring photogrammetric best practices are maintained. The ability to modify a flight plan introduces the possibility of creating more complex automated flight plans for improved workflows.

abstract: M.Sc.


title: Moving the Academy to Hip Hop Music: Repurposing Canadian Universities with Black Radical Traditions

contributor:
McKittrick, Katherine
Cultural Studies

rights: Attribution-NonCommercial-NoDerivs 3.0 United States

subject:
Black Studies
Hip Hop
Canadian Academy
WondaGurl
Black Canada

abstract:
This project analyzes the important and knotted interventions that hip hop artists bring to the Canadian academy. I think through how university institutions preserve white supremacist values alongside diversity mandates and show that the displacement of black histories and black knowledges—which in fact favour myths of a colour-blind and benevolent Canada—creates barriers to learning. This displacement is coupled with the ways many universities in North America often commit to teaching hip hop music on neoliberal terms; these institutions often put forth multicultural policies that centre normative ways of knowing and a politics of inclusion that undermines black intellectual work. This dissertation theorizes that the teachings of black popular culture and hip hop interrupt and recast these kinds of white supremacist educational practices. Hip hop pedagogies can and do restructure the classroom in the wake of ongoing antiblackness and colonialism. I address how black Canada is a contested historical site that informs learning practices and I think through radical classroom spaces that are founded on black activism. I pair these historical contestations and radical learning sites with analyses of the sub-discipline of Hip Hop Studies as well as the pedagogical underpinnings of hip hop. Interviews with faculty also comprise part of my research and uncover the complexities of teaching hip hop and black studies in North America. Points of my dissertation take up Canadian producer WondaGurl whose beats, flows, and samples allow me to engage the question of pedagogy through aesthetics and music-making and centre how music and music-making are connected to emancipatory practices.
My dissertation ends with a syllabus designed for an upper year undergraduate course that focuses on WondaGurl. I imagine this course as a pedagogical moment for (co-)production, wherein the students listen to her work and position it in conversation with academic texts that centre black histories and radical imaginations. In this way, my dissertation concludes by enmeshing theory with practice, and highlighting the pedagogical and emancipatory possibilities of black popular cultures.

abstract: PhD


title: Meeting Epistemic Challenges in Psychiatry With Embodied Cognition

contributor:
Sismondo, Sergio
Philosophy

subject:
Embodied Cognition
Cognition
Psychiatry
Antirealism
Predictive Processing
Medicalization

abstract: Psychiatry faces epistemic problems because of its roughly dualist philosophy of mind. Theory and practice that implicitly or explicitly separate mind and body challenge psychiatry’s ability to describe, meet and treat its patients. This is particularly problematic because psychiatry has a tendency to reify diagnoses and over-medicalize patients. Reliance on inferential modes of knowing downplays the role of intuitions in the diagnostic process. Embodied cognition offers a theoretical remedy for psychiatry. The argument proceeds in three parts. The first part provides background, in the form of brief overviews of several relevant positions and issues. First is psychiatric theory’s dualism, and connected problems of epistemic access. Next, the roles of antirealism and realism are related to research trends and the political stance of psychiatry. Third, the current state of affairs is entrenched by psychiatric pedagogy and arises from psychiatric history. Last, the standard model of cognition used in psychiatry is described. The second part reviews work in embodied cognition, which rejects, or at least modifies, the standard view of cognition. Theories established by Michelle Maiese and Andy Clark are used to generate a concept of an agent as an affectively framed predictive processor. The third and final part of the argument illustrates how an embodied understanding of cognition informs the clinical work of the psychiatrist. Intersubjective knowing is defined and shown to reflect an embodied understanding, which privileges intuition as epistemically valuable. Adopting an embodied view of cognition changes the process of diagnosis in psychiatry, in particular by altering the definitions psychiatry employs for disorder and normality. On a deeper level, the etiology of psychiatric disorders is shown to be more causally embodied. Embodiment is posited as being a specific focus for psychiatric treatment, especially in the realm of psychotherapy. The argument demonstrates the theoretically narrow position of current standard psychiatry and presents an additive theoretical stance, in the form of embodied psychiatry. This stance opens up areas for practice and research that are likely to be beneficial to the treatment of patients.

abstract: M.A.


title: Advances in the Detection and Characterization of Nonstationary Processes: An Application to Riometers

contributor:
Thomson, David J
Takahara, Glen
Mathematics and Statistics

subject:
Riometer
Multitaper Spectral Analysis
Time Series Analysis
Probability Theory
Statistical Signal Processing
Space Weather
Monte Carlo
Nonstationarity

abstract: Spectral-correlation detectors are used to determine if a stochastic temporal process contains nonstationary components from both the classes of spectrally-correlated and generalized almost-cyclostationary processes. The established multitaper spectral-correlation detectors are derived using solely the like-taper, cross-frequency, rotational and reflectional correlations between the eignecoefficient variables for the discrete Fourier transform of the temporal process. While this assumption is reasonable for the null hypothesis of zero frequency-offset spectral correlation, it is shown in this work to be less reliable for an alternative hypothesis of nonzero frequency-offset spectral correlation. Novel spectral-correlation detectors are introduced which account for the cross-taper, frequency-offset correlations between the eigencoefficient variables as well as the total correlation between them. In the asymptotic limit of increasing record size, these detectors are invariant to linear transfer functions. The test power and the robustness of the asymptotic quantile estimates to the process finitedimensional distributions is explored. The voltage series of a relative ionospheric opacity meter is considered for analysis. This instrument is sensitive to opacity fluctuations in the ionospheric D-region, and so it is used to monitor and forecast space-weather conditions. Results suggest that a complex-Gaussian approximation for the eigencoefficient variables is accurate. In this work, novel theory is introduced to help justify this distributional behaviour. The theory reveals a class of processes which can be used to assess the model uncertainty of the different spectral-correlation detectors, but it does not provide convergence rates over the record size. Therefore, a simulation study has been carried out to determine possible record sizes for which holds the aforementioned complex-Gaussian behaviour. For the considered riometer voltage series, results of this simulation study suggest that a 54-day record length at 120-second sampling period might well be sufficient for the complex-Gaussian behaviour to hold. Throughout the analysis, interesting periodic components are found in the voltage process.

abstract: PhD


title: Spatiotemporal Patterns of White-Tailed Deer Habitat Use on Hill Island in Thousand Islands National Park of Canada

contributor:
Danby, Ryan
Environmental Studies

subject:
Deer
Thousand Islands
Habitat Use
Thousand Islands National Park

abstract: White-tailed deer (Odocoileus virginianus) are hyperabundant in parts of Thousand Islands National Park because of their ecological impact on its forests.  To manage the high number of deer on Hill Island, an annual population reduction occurs in the park.  This study is intended to inform managers on the seasonal habitat use of the island by deer, so they are better able to evaluate impacts on affected forests.  Winter aerial surveys (10 historical surveys from 1992-2006, supplemented by surveys in 2018 and 2019) and seasonal deer pellet counts (winter 2018, summer 2018, winter 2019) were conducted to estimate resource selection and habitat use on Hill Island in Thousand Islands National Park.  Recent aerial surveys were also used to test locational accuracy and detectability of observations during flights.  Relative predictive surfaces were generated in a geographic information system where they could be compared to seek patterns of deer use contingent on method or season.  Winter aerial surveys did not corroborate winter pellet surveys well.  Detectability of deer during aerial surveys varied by cover type, and biased model results towards less important habitats.  Model validation indicated that the selected aerial model had modest predictive capability at the scale used.  Conversely, hilltops and areas with a high probability of hemlock occurrence, concentrated on the centre of the island, were judged to be high relative use areas by deer in winter when using pellet counting.  Summer use was not well-predicted by any of the habitat variables tested, and spatial patterns were different than winter estimates.  The results suggest that forest restoration and monitoring efforts in the park might be best focussed on upper elevation, high hemlock content areas in the centre of Hill Island to account for concentrated winter use there. Results also point to the need for an assessment of habitat use at a broader spatial extent to examine seasonal deer movement within the entire Thousand Islands region.

abstract: M.E.S.


title: Essays on the Canadian Mortgage Market

contributor:
Clark, Robert
Economics

subject:
Mortgage
Negotiated-Price Market
Dynamic Competition
Macroprudential Regulation

abstract: In this thesis, I investigate economic and policy issues presented in the Canadian mortgage market. In Chapter 2, I describe the institutional details and recent macroprudential regulations targeting the mortgage market--especially the mortgage stress tests. In Chapter 3, co-authored with Jason Allen, we develop a framework for investigating dynamic competition in markets where price is negotiated between an individual customer and multiple firms repeatedly. Using contract-level data for the Canadian mortgage market, we provide evidence of an “invest-then-harvest” pricing pattern: lenders offer relatively low interest rates to attract new borrowers and poach rivals' existing customers, and then at renewal charge interest rates which can be higher than what may be available through other lenders in the marketplace. We build a dynamic model of price negotiation with search and switching frictions to capture key market features. We estimate the model and use it to investigate (i) the effects of dynamic competition on borrowers' and banks' payoffs, (ii) the implications of dynamic versus static settings for merger-studies, and (iii) the impacts from stress tests on mortgage renewals. In Chapter4, co-authored with Robert Clark, we show that Canadian banks behaved strategically to limit the efficacy of the mortgage stress tests, which require borrower qualification based on the mode of 5-year rates posted by the Big 6 banks rather than negotiated transaction rates. The government aimed to cool credit markets, but since many mortgages are government-insured, Big 6 interests were not aligned. Using a difference-in-differences approach comparing the change in 5-year spreads with the change in 3-year spreads, unaffected by the policy, we find benchmark qualifying rates were  lowered to encourage continued borrowing, muting the impact of the stress tests on borrower qualification.

abstract: PhD


title: The Role of Ultraviolet Radiation in the Development of Skin Cancer and Non-Hodgkin Lymphoma in Canada

contributor:
King, Will
Brenner, Darren
Public Health Sciences

subject:
Ultraviolet Radiation
Indoor Tanning
Sun Behaviours
Skin Cancer
Non-Hodgkin Lymphoma
Melanoma
Non-Melanoma Skin Cancer

abstract:
Background: Exposure to ultraviolet radiation (UVR) is an established cause of melanoma and non-melanoma skin cancer (NMSC) and moderate exposure is hypothesized to be protective against some non-cutaneous cancers, including non-Hodgkin lymphoma (NHL). The first aim of this thesis was to estimate the current and future burden of melanoma and NMSCs associated with UVR and modifiable UVR behaviours in Canada. The second aim was to explore the relationship of time spent in the sun and the risk of NHL in a Canadian setting.

Methods: The burden of skin cancer associated with UVR in 2015 was estimated by comparing 2015 rates of melanoma and NMSCs with estimated rates of a 1920 birth cohort for melanoma and with rates of less exposed body sites (trunk and legs) for NMSCs. Skin cancer attributable to modifiable UVR behaviours (indoor tanning, sunburn, and sunbathing) was estimated using relative risks relevant to Canada by conducting meta-analyses and prevalence of exposures from a nationally representative survey. A prospective cohort study examining the risk of NHL was conducted using self-reported questionnaire data from three Canadian cohorts that were linked to cancer incidence data. Multivariable Cox proportional hazards models, using age as the time-scale was employed to investigate this relationship with control for relevant confounders.

Results: For 2015, we estimated that 62.3% of melanomas, 80.5% of basal cell carcinomas (BCC), and 83.0% of squamous cell carcinomas (SCC) were attributable to UVR, while 29.7% of melanomas, 46.0% of BCCs, and 17.4% of SCCs were attributable to modifiable UVR behaviours. Compared to individuals spending < 30 min/day in the sun the risk of developing NHL was 0.84 (95% CI: 0.55-1.28) for 30-59 minutes, 0.63 (95% CI: 0.40-0.98) for 1-2 hours, and 0.91 (95% CI: 0.61-1.36) for > 2 hours.

Conclusions: Prevention efforts aimed at modifiable UVR behaviours are crucial for reducing the burden of skin cancer in Canada, while moderate exposure to the sun may reduce the risk of NHL. Further research is required to clarify the optimal UVR exposure patterns in terms of preventing the development of both cutaneous and non-cutaneous cancers, including NHL.

abstract: PhD


title: Vulnerable, Valuable, and Vital: Exploring Perceptions of Academic Literacy in the First-Year College Classroom

contributor:
Beach, Pamela
Education

subject:
Academic Literacy
College Writing
Colleges
Metaphor

abstract:
The perspectives of college students and teachers regarding academic literacy are largely absent from literature on literacy in higher education, particularly in Canada. This study addresses this gap by centering the perspectives of first-year college students and teachers from one college in southern Ontario.

For the purposes of this research, I define academic literacy as the nuanced blend of critical attention, creative processes, and cognitive skills that are necessary to communicate successfully in school, across disciplines and levels of study. My research has been guided by the following questions: How do college students and teachers perceive academic literacy during the first year of college? What do the metaphors college teachers create about academic literacy reveal about their perceptions? What do the metaphors college students create about academic literacy reveal about their perceptions? And, how do these perceptions of academic literacy change over time, specifically in the context of the first-year experience?

To answer these questions, I designed an artful, multi-phase metaphoric study consisting of three phases that was guided by a hermeneutic analysis approach. During Phase 1, I visited participating first-year college courses and delivered a creative writing workshop that guided participants through the process of creating their own metaphors for academic literacy. In Phase 2, I met one-on-one with participants for a think aloud task and a semi-structured interview. Finally, during Phase 3, I met with participants for member checking and a final conversational interview.

This study theorizes four preliminary threshold concepts of academic literacy in the first-year college classroom in order to inform both research and praxis in this transitional space. These threshold concepts, combined with the academic literacy lenses Lea and Street proposed that I explore in Chapter 3, form the conceptual framework of this study. Based on this work, teachers, students, and researchers can approach transitional academic literacy as transdisciplinary, as tied to privilege and identity, as a tool for transformation, and as something deeply connected with a range of emotional responses. Further, this work contributes a new approach to academic literacy research through a multi-phase metaphoric study design.

abstract: PhD


title: Ability to Extract Extrafoveal Information Modulates Object Processing in Naturalistic Scenes

contributor:
Castelhano, Monica
Psychology

subject:
Scene Perception
Object Processing
Visual Cognition
Extrafoveal Processing

abstract: In naturalistic scene processing, individuals adopt multiple resources to facilitate their object identification processes. For instance, scene context information contains many cues to facilitate recognition of an object, including the scene gist category and other semantically related objects. Similarly, individuals’ capacity to allocate attention independently from eye-movement suggests extrafoveal processing under circumstances where target objects are not in the center of fixation. Previous studies have shown that target-related objects or scene context, as well as extrafoveal processing of the object, may boost object perception. However, very few studies have examined the effect of multiple sources of information on object processing simultaneously.  In the present study, we investigated whether scene context and distance from fixation would interact and influence individuals’ object identification. Using a modified dot-boundary paradigm, we manipulated the distance of objects in relation to the fixation so that participants have varying difficulty in processing the objects with peripheral vision. Crucially, we examined whether individuals’ ability to extract extrafoveal information was modulated by a semantically related scene context. Our findings revealed a robust preview effect, although there was no scene context effect and nor a context-preview interaction. Altogether, our data suggest individuals may have chosen to rely on one route of facilitation when the other path is restricted.

abstract: M.Sc.


title: Do Species with Strong Apical Dominance Incur a Cost in Terms of Suppressed Potential Fecundity or Biomass?

contributor:
Aarssen, Lonnie
Biology

subject:
Overcompensation
Tolerance
Plant Ecology
Meristem Allocation
Apical Dominance
Leaf Size Variation
Herbaceous Angiosperms

abstract: Plants typically allocate axillary meristems to one of three principal fates: growth (G), reproduction (R), or inactivity (I). The latter is commonly enforced by ‘apical dominance’, promoting a growth form that favours vertical shoot extension — mediated by the effects of auxin produced in the shoot apical meristem. When the latter is removed however (e.g. by herbivores), meristem allocation may change, thus affecting plant architecture, biomass accumulation, and/or reproductive effort. Fecundity and/or plant mass may consequently suffer (under-compensate), remain unaffected (compensate), or increase (overcompensation). The latter signifies a ‘cost of apical dominance’, but one that may be outweighed by several potential benefits from having apical dominance intact. I removed the shoot apical meristem for replicate plants early in the growing season within natural populations of 22 herbaceous angiosperm species with a conspicuously vertical growth form commonly found in eastern Ontario to: (i) test for a cost of apical dominance; (ii) examine effects on leaf size and leafing intensity; and (iii) explore effects of between-species variation in leafing intensity on propensity for a cost of apical dominance. Clipped and unclipped plants had their near neighbours removed, and were harvested after flowering production had finished but before seed dispersal. Dry mass was measured separately for above-ground body size, leaves, seeds, and fruit; and counts were recorded for each type of meristem, and number of leaves, fruits, and seeds per plant. I predicted that: (i) species with a strong apically-dominant growth form would respond to shoot apical meristem removal with greater branching intensity, and thus over-compensation in terms of fecundity and/or biomass; and (ii) overcompensation is enabled by production of more but smaller leaves, and hence with a larger bank of axillary meristems available for deployment in branching and/or fruit production. Widely variable compensatory capacities were recorded, suggesting effects of uncontrolled between-species variation in phenology, life history traits, and natural susceptibility to herbivory. I also found no significant between-species relationships for compensatory response versus mean leaf size or leafing intensity. Overall, the results point to species-specific treatment effects on meristem allocation patterns, and no generalized ‘cost of apical dominance’ in herbaceous plants.

abstract: M.Sc.


title: Causes and Effects of Variation in Wrist Range of Motion: Investigating the Kinematics of the Proximal Carpal Row

contributor:
Rainbow, Michael
Mechanical and Materials Engineering

subject:
Kinematics
Carpal Bones
Scaphoid
Lunate
Triquetrum

abstract:
Due to the complex nature of the wrist, we still do not fully understand how the healthy wrist functions. There are few muscle insertions at the wrist, so bone motion is induced by passive ligaments and bone to bone contact, making carpal bone kinematics challenging to understand and model. This challenge is magnified by subject-specific variation in ligament properties and bone shape. Previous work has linked variation in carpal bone motion to changes in wrist flexibility, but these investigations have focused on the radial side of the wrist. Thus, many potential causes of variation in carpal motion patterns have yet to be thoroughly explored.

To further understand the causes and ramifications of variation in normal carpal kinematics, we performed two studies using a database of 3D in vivo carpal bone postures. For the first study, we investigated variation in carpal bone motion on the ulnar side of the wrist. Contrary to theories embedded in the literature, we found that the triquetrum and lunate did not move in synchrony across a variety of functional wrist movements. We also identified a relationship between motion of the triquetrum and wrist laxity during wrist movement from 20° of radial deviation to 20° of ulnar deviation. During this movement, the component of flexion-extension in the motion of the triquetrum increased with increased wrist flexibility. In our second study, we investigated the influence of scaphoid shape on wrist flexibility. We found that the first two principal components of scaphoid shape were correlated with wrist flexion and extension range of motion, respectively. We also found evidence that scaphoid posture may be independent of scaphoid shape. Scaphoid posture affected the amount of scaphoid rotation during wrist flexion and extension.
Finally, we discuss how we can apply our findings to the development and evaluation iof surgical techniques through two ongoing projects: simulating wrist motion in cadaveric specimens, and investigating how scaphoid shape impacts screw placement following scaphoid fracture. The findings from this work provide insights about the intricacies of carpal bone motion, a step towards explaining differential responses to injury and treatments with the potential to inform targeted, patient-specific interventions.

abstract: M.A.Sc.


title: The Debate Surrounding the Use of Biometric Registration by the UNHCR on Refugees

contributor:
Lyon, David
Sociology

subject: Biometrics Refugees Surveillance

abstract:
Over the past two decades, there has been a disturbing rise in the refugee population with over 65 million people displaced from their homes as of 2019. This alarming increase has been due to terrorist activities, civil war and drought which led to people seeking refuge in neighbouring countries or heading to Europe or North America for a better life. This along with the terrorist attack of September 11th, gave rise to the use of biometric technology as a means of population, security and migration control. It is considered by many in the security community as the most accurate means of determining a person’s identity and is the main mechanism used by most NGOs and governments when dealing with refugees, which has given rise to discussions surrounding its impact and efficacy. This thesis explores the debate surrounding the use of Biometric technology on such a vulnerable population and how the collection of such data impacts the lives of these people.
To analyze this debate, articles from several academic researchers as well as documentation written by non-governmental organizations will be examined under the framework of documentary research. This study explores the issues surrounding the global refugee crisis and the rising expansion of biometric technology in various facets of the refugee migration process. It attempts to show the impact the collection of biometric data has on refugees and the refugee process as well as display the overall perceptions society has regarding biometrics and refugees.
	This research finds that although the use of biometric technology is essential to the refugee process, there are several adverse effects with the use of such technology on a vulnerable population.

abstract: M.A.


title: Numerical Investigation of an Aircraft Thermal Management System

contributor:
Harrison, Stephen
Mechanical and Materials Engineering

subject:
Aircraft Thermal Management System
Fuel Thermal Management System

abstract:
Thermal management requirements in modern aircraft have been increasing over time, driven by the increase in the thermal loads generated by a variety of electronic components and hydraulic systems. A literature review has suggested that using the fuel, which is meant for propulsion, to collect the heat generated and reject part of it to the ambient is the most effective method to achieve thermal management in the current generation of aircraft. The analysis presented in this thesis thus focused on the performance of fuel thermal management systems (FTMS) for managing the various thermal loads in an aircraft. The FTMS model consisted of four major components including a fuel storage tank, high-temperature and low-temperature heat exchangers and bypass-loop with proportioning valve. To facilitate the analysis, the FTMS was numerically modelled using a “systems” approach based on the principles of conservation of mass and energy. From this theoretical model, a numerical model of the FTMS was developed in the MATLAB/Simulink programming environment. For the model, the system’s heat exchangers were simulated using a logarithmic-mean temperature-difference (LMTD) approach. The model also considered variation in air and fuel properties with temperature and altitude conditions. The numerical model was compared against values published in the literature and then used to perform parametric studies for both uniform (i.e., constant altitude and cruise speed) and non-uniform (i.e., variable altitude and cruise speed) flight conditions. The research considered three primary operational conditions for the FTMS, namely: (1) a specified operating temperature for heat-dissipating elements, (2) a specified heat removal rate, and (3) a specified fuel temperature. The performance of the FTMS was evaluated for these three operational modes during both uniform and non-uniform flight conditions. In each case, the variations in the heat transfer rates and temperatures at critical point in the FTMS were calculated for a variety of flight conditions. These conditions included variations
iii
in altitudes, cruise speeds, fuel burn rates, high-temperature and low-temperature heat exchanger capacities, fuel tank heat-losses and fuel recirculation rates. The results of this analysis indicated that when the heat source temperature was maintained at a constant value, the heated fuel temperature increased, and the heat removal capacity degraded over the duration of flight. Conversely, for a prescribed heat removal capacity, both the heat source temperature and heated fuel temperature increased during the flight. Lastly, when the desired heated fuel temperature was specified, it was observed that the heat source temperature and the heat removal rate both decreased over time. It was concluded that the optimum fuel recirculation rate was a complex function of variables, thus highlighting the need for a dynamic control strategy.

abstract: M.A.Sc.


title: The Impact of Marketing on the Financial Services Sector: An Empirical Investigation

contributor:
Kolsarici, Ceren
Nediak, Mikhail
Business

subject:
Price Discrimination
Price Optimization
Consumer Credit
Risk-Based Pricing
Financial Services
Sales Incentives
Sales Force Compensation
Sales Force Pricing Delegation
Consumer Lending
Financial Advisors
Consumer Heterogeneity
Latent Class Choice Model

abstract: We examine the role of marketing within the financial services sector by conducting three empirical examinations that involve pricing, sales force compensation, and targeting/positioning. Beginning with the first essay, we examine the profit implications of risk-based pricing, using the context of indirect lending, which involves a lender, sales agent, and customer. To account for the decisions made by each of these stakeholders, we develop a three-stage choice model that allows us to quantify the impact of various factors on each of these decisions. Using the estimates from this model, we optimize the customer rate and agent incentive for each risk segment, determining that risk-based pricing increases lender profitability by 26%. In the second essay, we examine the behaviour of external sales forces, again using the context of indirect lending. We find that commission impacts both the demand allocation and pricing decisions made by external sales forces, albeit to a larger extent for the pricing decision. Given the impact of commission on these decisions, we optimize the commission rate for each price on the focal lender’s menu of prices, finding that commission should exponentially increase with price to alleviate moral hazard concerns that arise when external sales agents select the lowest price to secure a sale. Optimizing commission in this way has a substantial impact on profitability, increasing return on adjusted capital by 1.33 percentage points. Finally, in essay three, we examine the motivational drivers behind customers’ decisions to use financial advisor services. A latent class choice model reveals two segments that differ in two important ways with respect to their motivations for seeking financial advice. First, although higher levels of trust, self-efficacy, and risk tolerance increase the probability of using financial advisor services for both segments, albeit to a larger extent for segment 1, personality only impacts segment 1. Second, we find that segment 1 is motivated by the extent of positive attitudes towards financial advisors (i.e. promotion focus) while segment two focuses on negative attitudes (i.e. prevention focus). Collectively, these essays increase our understanding of the role of marketing within the financial services sector, answering research questions that have gone unanswered by academics and providing practitioners with tools to improve marketing effectiveness.

abstract: PhD


title: Growing Concern: The Evolution of Urban Agriculture in the Context of Montréal, a Gentrifying City

contributor:
Donald, Betsy
Geography and Planning

subject:
Urban Agriculture
Urban Political Ecology
Eco-Gentrification
Montréal
Negotiated Planning

abstract: Urban agriculture is a growing trend in cities worldwide but there is concern in the literature that urban agriculture can contribute to the phenomenon of eco-gentrification. Eco-gentrification is the process whereby the environmental improvement of a neighbourhood increases land values, contributing to the gentrification process. When this occurs, urban agricultural projects increase land value and may attract new residents as part of the gentrification process, which can then displace older and less-affluent residences in the neighbourhood. Montréal, Québec is one such city where eco-gentrification may be occurring. Montréal is home to a rich history of urban agriculture and some of the world’s first rooftop gardens, and urban agriculture is only growing in popularity. My main research question asks whether the eco-gentrification process is occurring in Montréal through urban agriculture. I am particularly interested in knowing why developers might be interested in including urban agriculture and how the local city government is implicated in this process. To answers these questions, I drew on theoretical insights from urban political ecology and also grey literature from government, industry and non-profit sources. I also conducted 15 semi-structured interviews with key informants, including developers, urban planners, and community actors. I found that there was some interest from developers to include urban agriculture in their projects, but there were many challenges associated with them doing so, especially around cost and logistics. The push for urban agricultural integration into new developments was found to often be instigated through negotiated planning, and through community groups and residents in certain situations. In addition, this study showed significant concern from community residents about the possibility of urban agriculture exacerbating already existing gentrification problems in Montréal. However, there is a plethora of different forms of urban agriculture that exist in Montréal, all with different ii aims, levels of community involvement, and consequence. Prior research has demonstrated that intention and method matter when it comes to the consequences of individual projects. Future research should study the impacts on particular neighbourhoods particularly where public incentive through funding or bylaw amendment is offered.

abstract: M.A.


title: Characterization of Tailings Dust from Two Abandoned Mine Sites: Effects on Nearby Surface Waters and Evaluation of Dust Sampling Methods

contributor: Geological Sciences and Geological Engineering

subject:
Dust
Tailings
Climate Change

abstract:
Canada’s climate is warming and as a result the hydrological cycle is expected to become more intense, with rainfall concentrated in extreme events with longer dry spells. Consequently, dry tailings may be more likely to blow into nearby surface waters. This research is an investigation into the geochemical effects of tailings dust on nearby surface waters and evaluates dust sampling methods used to investigate seasonal trends. During this study, two abandoned mine sites in Nova Scotia, Canada were investigated: Stirling Zn-Pb and Goldenville Au mine.
At Stirling, tailings were sieve to <63μm as a proxy for dust and analyzed to determine metal concentrations and identify primary and secondary metal-bearing phases. Metal-hosting phases identified include sphalerite, smithsonite, aurichalcite, hydrohetaerolite, goethite. tennantite, galena, cerussite, Pb-Mn phases, and chalcopyrite. Shake flask tests were conducted to investigate dust solubility in simulated stream waters (pH=7). Results indicate that dust particles are partially water soluble in the shake flask test and that sphalerite, cerussite and chalcopyrite are likely the main sources of Zn, Pb and Cu in the shake flask leachate, based on calculated saturated indices and mass balance. Analyses of stream water indicate similar conditions (pH, Eh, etc.) and saturation indices compared to shake flask tests, and therefore provide reasonable insight for processes occurring the field.
Dust was also sampled using a variety of different methods to identify the most suitable method for seasonal sampling. These included passive dry deposition collectors (PAS-DDs), high volume total suspended particle (TSP) sampler (HVAS), dust deposition gauges (DDGs), and lichen. Results indicate that Pas-DDs with a glass fiber filters (GFF) and dust deposition gauges likely underestimate dust deposition. In comparison, Pas-DDs with a polyurethane foam disk (PUF) efficiently accumulate dust. However, PUFs had additional challenges including metal(loid)s within the filters themselves, difficulty obtaining stable weights, and potential dust collection from the sides and bottom. Despite difference between dust sampling methods, it was observed that dust deposition was highest in the winter months due to higher wind speeds. Future dust generation remains difficult to predict due to the unknown combined effect of changes in temperature, precipitation, evaporation, and wind speed.

abstract: M.Sc.


title: Impact of Environmental Variability on Net Ecosystem CO2 Exchange from 2008-2018 at a High Arctic Mesic Tundra Site

contributor:
Treitz, Paul
Scott, Neal
Geography and Planning

subject: Carbon Dioxide Exchange

subject: Net Ecosystem Exchange (NEE)

subject: High Arctic

subject: Inter-Annual Variability

subject: Mesic Tundra

subject: Normalized Difference Vegetation Index (NDVI)

abstract: Arctic terrestrial carbon (C) budgets are shifting with respect to net ecosystem CO2 exchange (NEE), and its component fluxes; i.e., gross primary production (GPP) and ecosystem respiration (Reco) under amplified high latitude climate change. Determining whether Arctic ecosystems are behaving as net sinks or net sources is important as these scenarios are associated with various feedback mechanisms, either mitigating or enhancing atmospheric CO2 concentrations. Given the vast C stores in Arctic soils and permafrost, these processes can have significant impacts on atmospheric CO2 concentrations. This research investigates how growing season NEE has varied from 2008 to 2018 at the Cape Bounty Arctic Watershed Observatory (CBAWO) (74.92˚N, 109.58˚W) on Melville Island, Nunavut, Canada. The eddy covariance technique and standardized processing tools were used to observe inter-annual variability of NEE, GPP, and Reco and the relative importance of environmental variables in explaining variability of growing season CO2 fluxes. Overall, this site showed strong inter-annual variability in growing season NEE (range of -46.01 g C m-2 to 11.25 g C m-2) with GPP the most likely source of this variability, i.e., GPP rates were more variable compared to Reco. Inter-annual variability of growing season NEE appeared to be strongly driven by growing degree days (GDD) in warmer years, suggesting that temperature must reach a threshold in order to drive photosynthesis sufficiently to offset respiration. This deviated slightly in 2014, the second strongest CO2 sink across observed years (-21.24 g C m-2), but with reduced cumulative GDD. This is believed to be a result of delayed ecosystem response to previous environmental conditions favorable for strong CO2 uptake. CO2 fluxes also showed varying importance in the context of environmental variables at different temporal aggregations, with the remote sensing vegetation index showing strong importance for Reco, compared to GPP and NEE, suggesting a significant contribution of autotrophic respiration to Reco at this mesic site.  This research reveals unique characteristics between inter-annual growing season CO2 flux patterns for a mesic tundra landscape and environmental drivers that overall, contribute to our understanding of High Arctic tundra CO2 dynamics.

abstract: M.Sc.


title: Neutron Measurements and Reactor Antineutrino Search with the SNO+ Detector in the Water Phase

contributor: Physics, Engineering Physics and Astronomy

subject:
SNO+
Neutrino Physics
Reactor Antineutrinos
Neutron Capture

abstract:
The SNO+ experiment is a large-scale liquid scintillator neutrino experiment with a wide range of physics objectives. SNO+ has adopted a staged approach where the detector was first filled with ultra-pure water before substituting with liquid scintillator and the target isotope $^{130}$Te for neutrinoless double beta decay. During the SNO+ water phase, an $^{241}$Am$^{9}$Be source is deployed across the detector volume to calibrate the detector's energy response and its response to neutrons. The $^{241}$Am$^{9}$Be source emits a unique coincidence signal with the prompt event being a 4.4 MeV $\gamma$ and the delayed a neutron capture signal (2.2 MeV $\gamma$).

A novel, minimalistic, statistical analysis of the $^{241}$Am$^{9}$Be calibration data was designed and used to measure the capture time constant $\tau$, capture cross-section $\sigma_{H,t}$, and the neutron detection efficiency $E_{\textrm{center}}$ at the center of the detector:
\begin{equation}
\begin{aligned}
&\tau = 202.35 \pm 0.42\ (stat.)\ ^{+0.38}_{-0.31}\ (syst.)~\mu\textrm{s}, \\
&\sigma_{H,t} = 336.3 ^{+1.2}_{-1.5}~\textrm{mb}, \\
&E_{\textrm{center}} = (50.8 \pm 0.6)\%.
\end{aligned}
\end{equation}

Additionally, with the help of Monte Carlo simulations, a volume-weighted neutron detection efficiency across the detector is evaluated to be $E_{\textrm{detector}} = (46.5 \pm 0.5\ (stat.\ only))\%$. The simulation is also central to an energy calibration using the 4.4 MeV $\gamma$ to measure the energy resolution and energy scale of the detector.

Finally, with $\sim$115 days of early water data, an upper limit, $\hat{\Phi}_{\bar{\nu}_e, \textrm{ult}}$ = $(1.76 \pm 0.29) \times 10^6 \bar{\nu}/(\textrm{cm}^2\cdot\textrm{s})$, on the reactor antineutrino flux for SNO+ is obtained using a maximum likelihood approach. The limit is about a factor of 9 higher than the expected signal in SNO+, which can be calculated using available reactor output power data.

abstract: PhD


title: Online Self-Management Treatment Program for Women Diagnosed with Interstitial Cystitis/Bladder Pain Syndrome

contributor:
Tripp, Dean
Psychology

subject:
Chronic Pain
Pain
Online Treatment
Psychosocial Intervention
Interstitial Cystitis
Bladder Pain Syndrome

abstract:
Interstitial Cystitis/Bladder Pain Syndrome (IC/BPS) is a chronic pelvic pain condition. An agreed-upon etiology for IC/BPS remains unspecified and medical treatment is often inadequate. Research has demonstrated the condition is associated with diminished quality of life (QoL), significant pain-related disability, greater pain catastrophizing, depressed mood, and decreased social support. Psychosocial treatments have been emphasized by health-care providers and researchers alike, but to date, no study has evaluated a psychosocial treatment program for this population. The literature suggests that online psychosocial treatments can effectively improve patient outcomes in various chronic pain samples.
The present dissertation aimed to develop and evaluate the efficacy of an online psychosocial self-management treatment program for women with IC/BPS. Based on the literature on this population and evidence-based treatments, the program targeted psychosocial risk factors (pain catastrophizing, depression, social support, disability), with the aim of improving QoL. An expert review was conducted to gather feedback on program content. A pilot study assessed patient perceived usability of and satisfaction with the intervention, which was rated as satisfactory, useful, and valuable by patients. Improvements were made in accordance with patient feedback and the literature. Finally, a wait-list randomized controlled trial (RCT) evaluated the efficacy of the online self-management treatment program. It was hypothesized that treatment group participants would obtain improvements on the primary outcome measures of physical and mental QoL, as well as secondary outcome measures of depression, disability, pain catastrophizing, and social support, when compared with control group participants. Although these hypotheses were not supported, treatment group participants’ 3-month follow-up pain catastrophizing scores were statistically lower than baseline, and there was a clinically meaningful reduction in pain catastrophizing scores for treatment group participants, when compared with control group participants, at study end. The program was deemed highly satisfactory to patients who completed it.
	Theoretical and clinical implications are discussed. Study results led to considerations for future research. Important limitations of the present study include a large attrition rate and threats to internal validity in follow-up period analyses. Overall, an online self-management treatment program may be a potentially useful intervention for women with IC/BPS, but further research is needed.

abstract: PhD


title: Essays in High and Low Frequency Price Discovery

contributor:
Riordan, Ryan
Nielsen, Morten
Economics

subject:
Price Discovery
Fragmentation
Fire Sales

abstract: In this thesis, I examine high and low frequency price discovery for US equity markets. In Chapter 3, I propose a methodology to disentangle high frequency price jumps into a permanent and transitory component. Using a variance decomposition and realized estimates I show that while jumps are extremely rare events, jump contribution to intraday price discovery is large. In Chapter 4, co-authored with Ryan Riordan, we examine the market dynamics of price jumps. We find that jumps have a predictable component which is captured by the degree of fragmentation in liquidity in minutes leading up to price jumps. Applying the methodology of Chapter 3, we show that fragmentation predicts noisier jumps. Lastly, in Chapter 5, co-authored with Evan Dudley, Luke Phelps and Ryan Riordan, we use mutual fund fire sales to decompose low frequency quarterly stock prices into an efficient and noise component. We show that more than a quarter of variance in low frequency stock prices is attributable to noise. Overall, this thesis finds that noise is an important component of both high and low frequency stock price variation.

abstract: PhD


title: Romantic Relationships and Leadership: Three Studies

contributor:
Barling, Julian
Business

subject:
Leadership
Work-Family Interface
Gender

abstract:
Questions of who becomes a leader, and what predicts the quality of their leadership behaviors, have been of interest to scholars and the public for decades. Although most explorations of antecedents to leadership focus on individual differences, scholars have speculated on the role of social-interpersonal contexts as potentially influential in shaping various leadership outcomes. I set out to examine how one central relationship outside of work, namely romantic relationships, shape how people lead, and whether or not they become a leader in the first instance. Drawing on ten Brummelhuis and Bakker’s (2012) Work Home-Resources Model, I examine three ways in which romantic relationship experiences spillover into leadership outcomes via their effects on personal resources.

In Study 1, I examine how current, personal romantic relationship behaviors indirectly influence leadership behaviors through resource gain and loss. Using a randomized-clustered experimental design (n = 93 couples), results show that for female partners, positive relational behaviors serve as a contextual resource that limits personal resource loss, resulting in more positive and less negative leadership behaviors. Negative relational behaviors are a contextual demand, increasing personal resource loss, and in turn, negative leadership behaviors. In Study 2, I consider how distal personal relationships affect leadership emergence, and specifically how adolescents’ experience of dating violence indirectly affects leadership role occupancy through depressive symptoms. Drawing on a longitudinal nationally representative sample (Add Health, n = 3277), results revealed that experiencing psychological aggression for females, and experiencing physical violence across genders, are contextual demands that independently result in depressive symptoms, in turn decreasing the leader role occupancy. In Study 3, I consider how distal and vicarious relationship experiences, namely adolescents’ observations of their parents’ domestic violence, indirectly affects leader emergence. Drawing on a nationally representative sample (NCS-R, n = 1701), I found that for females, witnessing interparental domestic violence in adolescence results in greater anxious and avoidant attachment, which in turn decreases leader role occupancy.

Together, results from these three studies point to the multiple ways in which romantic relationship behaviors influence leadership across the lifespan, and the critical role of gender in determining whether this spillover occurs.

abstract: PhD


title: Machine Learning QoE Prediction for Video Streaming over HTTP

contributor:
Hassenein, Hossam
Computing

subject:
Quality of Experience (QoE)
HTTP Adaptive Video Streaming (HAS)

abstract:
Streaming video services have been growing rapidly in the past decade due to the wide adoption of more capable mobile devices such as smartphones and tablets, together with the deployment of higher capacity mobile networks and more efficient video compression and streaming techniques. Dynamic adaptive streaming over hypertext transfer protocol (DASH) can adapt bitrates to fluctuating network bandwidth. This makes measurement of perceived video quality a significant task. Therefore, there has been a strong demand for Quality of Experience (QoE) measurements and prediction models. The work in this thesis focuses on improving the performance of existing QoE prediction models that still have a few limitations. We propose a feature enhancement approach for QoE prediction using machine learning (ML) methods.  Given the need for an accurate and reliable data set to do our analysis, train and evaluate our machine learning models, we utilize the Waterloo Streaming QoE Database III (SQoE-III) that combines the effects of video compression, initial buffering, and stalling events along with the subjective user responses to them. Additionally, the database contains the results of implementing various objective video quality assessment (VQA) models.
First, we perform an extensive data and correlation analysis to study the effects of the different QoE key influence factors (KIF) which account for the video quality degradation. We further study the effect of quality switching that includes switching up and down, switch magnitude, ratio/time spent on the highest quality level/layer, in addition to the effect of stalling expressed as the number of stalls and their duration and initial buffering time. We analyze the effect of various objective video quality assessment (VQA) models on the QoE. The results of the analysis reveal the dependency between objective VQA models features, playback stalling, and quality switching features that affect the QoE. Towards effectively predicting user QoE and based on the results of our analysis, we identify/introduce a new set of enhanced features that combine objective VQA features, playback stalling features, and quality switching features, as input to various machine learning models to predict the values of QoE. Experimental results show that the proposed models are in close agreement with subjective opinions and significantly outperforms existing QoE prediction models and can also provide a highly effective and efficient future for QoE prediction in video streaming services.

abstract: M.Sc.


title: Acute Physiological Effects of Brain-Generated 17β-Estradiol in the Rodent Primary Auditory Cortex

contributor:
Dringenberg, Hans
Neuroscience Studies

subject:
Synaptic Plasticity
Long-Term Potentiation
Neuromodulation
Estradiol
Aromatase

abstract: The neuroactive steroid hormone 17β-estradiol (E2) modulates synaptic activity and plasticity in both endocrine and non-endocrine forebrain regions of males and females of a variety of species. Research conducted in songbirds has established that E2 is rapidly synthesized in the auditory forebrain in response to salient auditory experience, and this locally-synthesized E2 contributes to auditory signal processing and learning. Despite the role of E2 in auditory processing and learning, together with its effects on synaptic activity and plasticity in non-sensory regions of the mammalian forebrain, particularly the hippocampus, the modulatory actions of E2 on synaptic plasticity mechanisms underlying learning and memory have not been directly investigated in the mammalian auditory forebrain. The studies described in this thesis examined the modulatory role of E2 in synaptic activity and plasticity in the rodent auditory forebrain. First, immunohistochemistry (IHC) was used to characterize neocortical expression of the estrogen synthetic enzyme aromatase in adult male rats. Aromatase was expressed by a large population of neurons in medial prefrontal cortex (mPFC), primary somatosensory cortex (S1), primary auditory cortex (A1), and primary visual cortex (V1). Next, in vivo field recordings were used to determine the effects of acute, bidirectional E2 manipulations on short- and long-term synaptic plasticity (paired-pulse responses and long-term potentiation; LTP) in A1. E2 significantly reduced the threshold for LTP induction at layer IV, thalamocortical synapses, whereas suppression of local E2 production by aromatase inhibition significantly reduced LTP induction at layer II/III, intracortical synapses. Acute E2 manipulations did not significantly alter paired-pulse responses in A1, suggesting a postsynaptic locus of the modulatory effects of E2 on LTP. Finally, ex vivo whole-cell recordings were used to explore the mechanisms underlying the E2-dependent modulation of LTP in A1. Agonist-evoked excitatory and inhibitory synaptic currents in A1 were sensitive to bidirectional E2 manipulations in a layer-specific manner, suggesting a role for E2 in maintaining the balance of excitation and inhibition in this region. These findings further our understanding of the modulatory role of E2 in sensory system function and plasticity and have broad implications for the study of learning and memory.

abstract: PhD


title: Development Length and Bond Strength of FRP Bars Embedded in Normal, High Strength, and Ultra-High-Performance Concrete

contributor:
Michaud, Decebal E.
Fam, Amir
Civil Engineering

subject:
Development Length
Bond Strength
FRP
UHPC
BFRP
GFRP
Small Cover
Small Diameter

abstract:
This thesis examines experimentally the development lengths (Ld) of small diameter (db) (4 mm, 6 mm, and 8 mm) basalt fiber reinforced polymer (BFRP) deformed bars embedded in concrete with compressive strength ranging from 41 to 70 MPa.  It also examines the development length of 17 mm diameter sand coated glass fiber reinforced polymer (GFRP) bars embedded in ultra-high-performance concrete (UHPC) with 2% and 4% steel fiber and 2% and 3% polyvinyl alcohol (PVA) fiber content. The compressive strength of the UHPC ranged from 87 MPa to 132 MPa.  Both studies used the notched beam testing method.

For the first study investigating small diameter BFRP bars, embedment lengths varied from 5 to 109 db and the clear concrete cover was 30 mm. The 44 notched beam specimens measured 101 x 203 mm in cross-section and varied in length from 610 to 1980 mm to accommodate various embedment lengths.  The bar axial stress at failure was plotted against embedment length for each set and linear regression was used to establish Ld based on the guaranteed tensile strength.  It was shown that as concrete strength increased from 41 to 70 MPa, Ld reduced from 32 to 20 db for the 4 mm bar, from 30 to 25 db for the 6 mm bar and from 52 to 23 db for the 8 mm bar. ACI440.1R-15 and CAN/CSA S806-12 design guides overestimated Ld of these small diameter bars.  Alternative equations for splitting and pullout are proposed and explained herein.

For the second study investigating sand coated GFRP bars, the embedment length was varied from 4 db to 16 db and the clear concrete cover was kept constant at 1.0 db.  The specimens experienced splitting bond failure. The average bond strength (τu) was higher in UHPC with steel fibers than PVA fibers.  It also increased with fiber content but reduced with embedment length. Consequently, Ld was smaller in UHPC with steel fibers than PVA fibers and was also reduced as fiber content increased.  The Ld values for UHPC with 4% steel, 2% steel, 3% PVA and 2% PVA were 20 db, 29 db, 35 db and 55 db, respectively.  ACI440.1R-15 (2015) and CAN/CSA S806-12 (2012) design equations provided very conservative estimations for Ld by factors of 1.5-5.7.  An alternative simple equation has been suggested for Ld.

abstract: M.A.Sc.


title: Characterization of Rock Salt Response to Blasting using Terrestrial Laser Scanning Technology

subject:
Remote Sensing
Rock Blasting
Rock Mechanics
Rock Salt
Underground Mining

abstract: This doctoral research project addresses some of the fundamental aspects for blast design methods in rock salt mines. An experimental field work protocol was devised based on the use of  single hole blast (SHB) tests to quantify blasting characteristics  in rock salt. Terrestrial laser scanner (TLS) surveys were implemented to capture the shape of SHB craters and enhance objectivity of the reporting methodology. This was done through large scale field testing carried out at three underground rock salt mines. A crater shape model in the form of a power law equation is proposed to define crater breakouts measured through field work. Rock salt characteristic mechanical properties were further analyzed in light of observed field measurements. The analysis led to the definition of a complementary cratering mechanism, due to  the interaction between emitted and reflected pressure waves,  to describe rock salt blasting  behaviour. A semi-iterative procedural workflow is proposed to derive site specific blast design guidelines in rock salt mines.  Practical applications of this procedure are presented and discussed, together with a few additional aspects that can help develop a more systematic and global method for optimizing blast patterns in rock salt mines .

abstract: PhD


title: Speaking Volumes: Publishers’ Bindings in English-Canada 1870-1920

contributor:
McNairn, Jeffrey
History

subject:
Publishers' Bindings
James Barry
Lorne Pierce
Print Culture
19th Century Bookbindings
John Lovell

abstract:
The nineteenth century saw a significant shift in how books were produced. Industrialization and the emergence of a mass reading public, whose members also had increased leisure time and money, led to the need for less expensive books than those bound by individual readers. Publishers’ bindings, the specific design created to address this need, also created the modern book, the book as we know it today. These bindings flourished in Britain and the United States between 1820 and 1920, but not in Canada.
This thesis will argue that while publishers’ bindings were not as extensive in English Canada between 1870 and 1920 as they were in Britain and the United States, they did exist, as evident in the three case studies: the individual binder James Barry, the businessman John Lovell, and the collection created by Lorne Pierce. Canada, to be sure, experienced the same changes that led to the need for less expensive books in Britain and the United States. Full of potential, a few circumstances unique to Canada nevertheless frustrated and delayed the development of a significant book publishing industry for several decades. Given the state of Canadian publishing circa the 1870s, Canadian authors were forced to seek external publishing outlets for their work. This, in turn limited the need for publishing innovations. Additionally, copyright laws provided further roadblocks to the publishing business in Canada, and subsequently affected the development of a national industry able to match the quantity and quality of its British and American counterparts. Through the use of three case studies, we will see that nonetheless bookbinders and publishers alike sought creative ways to circumvent the challenges and produce these uniform bindings.

abstract: M.A.


title: Adult Literacy: Challenges Facing Adult Syrian Refugees With Minimal Or No Prior Formal Schooling

contributor:
Myers, Maria
Education

subject: Adult Literacy

subject: Refugees

subject: Syrian Crisis

subject: Pre-Migration and Post-Migration Experiences and Challenges

abstract:
The 1951 Geneva Convention relating to the Status of Refugees describes a refugee as a person who "owing to a well-founded fear of being persecuted... is unable to or, owing to such fear, is unwilling to avail himself of the protection of that country. " (UNHCR web site). Every year, millions of people around the world are forced to leave their homes to save their lives. The UN Refugee Agency (UNHCR, 2019) points out that over 80 million people are currently displaced due to different reasons, such as armed conflicts, famine, diseases, and other natural disasters. Recently, the catastrophic wars in the Middle East obliged millions of people to flee their home countries and seek refuge in safer places. The purpose of this study is to explore the reasons and the effects of limited English literacy skills from the perspectives of the two groups of the study participants (the Syrian participants and the ESL teachers) on the Syrian participants' integration and the resettlement process. This research study follows a qualitative research design by conducting semi-structured one-on-one interviews with the eight adult male Syrian participants and the four ESL teachers.

The data analysis process started with open codes. Then, similar codes were grouped together to form themes and subthemes. The results indicated that all Syrian participants left their schools at an early age in Syria because they wanted to get a job to help their families. Secondly, they pointed out that their major challenge after moving to Canada was the English language which hinders their integration process. On the other hand, the ESL teachers pointed out that they need more training sessions on how to teach and deal with different refugee students coming from different parts of the world. Besides, they mentioned that the curriculum guidelines they use at their school do not meet the students' learning needs. The study concludes with recommendations for a better understanding of the urgent needs of the refugee students to help them understand the language as well as the culture of the host country.

abstract: M.Ed.


title: The Influence of Catecholamines on Working Memory and the Activational Aspects of Motivation

contributor:
Paré, Martin
Neuroscience Studies

subject:
Working Memory
Motivation
Neuroscience
Methylphendiate
Atomoxetine
Acute Tyrosine Phenylalanine Depletion
Cognition
Rhesus Macaques

abstract:
Catecholamines are thought to have a major modulatory effect on cognition. However, there is only equivocal evidence that catecholamines have a direct impact on cognition. A body of research suggests that catecholamines influence motivation, through which they may have an indirect effect on cognition. Theories of motivation distinguish directional (behaviour toward or away from some stimuli) and activational aspects of motivation. The activational aspects of motivation (or behavioural activation) refer to the quantitative and qualitative features of motivated behaviour (speed, vigour and persistence) that enable organisms to overcome constraints that prevent them from obtaining a motivational stimulus.

Here we investigated the contribution of catecholamines to cognition (using working memory as a cognitive model; working memory is a limited-capacity cognitive process that temporarily retains relevant information to guide thoughts and actions) and behavioural activation by augmenting catecholamine neurotransmission using the catecholamine reuptake inhibitors methylphenidate (MPH; 0.1-10 mg/kg) and atomoxetine (ATX; 0.01-1.0 mg/kg) in adult female Chinese rhesus macaques (Macaca mulatta). We also tested the effects of diminishing catecholamine neurotransmission on working memory and behavioural activation using an acute tyrosine phenylalanine depletion (ATPD) method, which we developed and demonstrated its effectiveness at impairing brain catecholamine synthesis and function. A visual sequential comparison (VSC) task, which allows the systematic manipulation of working memory load was used to assess working memory. Behavioural activation was assessed using several measures: the animals’ reaction time (speed), saccade peak velocity (vigour), successful trial completion (persistence), successful trial initiation (persistence), trial initiation time (speed), and anticipatory trial initiation (vigour) in the VSC task. A visual progressive ratio (PR) schedule of reinforcement task was also used to assess behavioural activation; the PR breakpoint reflects persistence. The results of the MPH, ATX and ATPD studies showed that catecholamines have little to no impact on working memory but a significant influence on behavioural activation.

abstract: PhD


title: Should the Rainbow have Black and Brown Stripes?: (Anti)-Racism and Coalitions in Toronto’s Rainbow Community

contributor:
Srivastava, Sarita
Sociology

subject: Anti-Racism Queer Allyship Performance

abstract: My dissertation research undertakes an in-depth analysis of queer (anti)-racism in Toronto’s rainbow community. My study is informed by ethnographic research methods, including semi-structured interviews with those who self-identify as part of the rainbow community, and my own observations at queer-focused events in Toronto such as the Greenspace Festival by the 519 and Pride Toronto’s annual parade. My analysis and findings are presented in three publishable articles. This portfolio-style dissertation manuscript also includes photographic images from my field work, and the script from my stage production We without You, an original theatre project that I created to reflect, analyse and disseminate my ethnographic research. In the first article I discuss how languages of capital accumulation, white (homo)nationalism and safety, are mobilized in order to produce race and racism in queer politics. Within contexts of intersectional tension I analyse how self-identified white participants conceptualize anti-racism allyship. In my second article I explore how conflict and confusion about appropriate allyship produced self-exclusion from anti-racism efforts. I found that allies experience tension as to their roles and potential responsibilities in relation to anti-racism, which often results in being uninformed about race-related issues and/or in their non-participation in anti-racism. With data and analysis from my first two articles I wrote and produced a stage production entitled We without You. The production is a knowledge mobilization project that addresses gaps in public knowledge and informs audiences about a range of experiences in the rainbow community shaped by intersections of race and queerness. My experiences writing and producing We without You and the role of performance as critical resistance against polarizing politics is the subject of my third article. I argue that performance as knowledge mobilization plays a crucial role in bridging academic work with public engagement by positioning sociological inquiry as an important contributor to public life. As a whole, this dissertation explores how race is produced in the rainbow community, examines the tensions involved with anti-racism allyship, and demonstrates the power of performance as critical resistance.

abstract: PhD


title: Elucidating Isoform Specific Roles of Calpain-1 and Calpain-2 in Breast Cancer

contributor:
Greer, Peter A.
Pathology and Molecular Medicine

subject:
Calpain
Triple Negative Breast Cancer
Metastasis

abstract: Breast cancer is the most frequently diagnosed women’s cancer in Canada. Average patient survival rates are high, but they are significantly reduced for those patients whose cancer reaches stage IV – metastatic disease. This study investigated the roles of calpain-1 and calpain-2 in metastatic breast cancer. Genetic knockout of CAPN1, CAPN2, and CAPNS1 genes allowed us to analyze the functions of these two calpain isoforms in the MDA-MB-231 triple negative breast cancer model cell line and to determine which isoform is responsible for the CAPNS1-knockdown related cancer cell phenotypes seen previously. We used the panel of knockout and rescue cell lines for in vitro studies and showed that both calpain isoforms play roles in protective effects against select chemotherapeutics, suggesting that calpain inhibition could enhance the efficacy of these commonly used breast cancer therapeutics. We also showed that genetic disruption of calpain-1 reduces the in vitro cell migration rate on collagen substrates. Our in vivo studies provide evidence that calpain-1 and calpain-2 have essential non-redundant roles in the metastatic process, suggesting that inhibition of either isoform could have therapeutic benefits by reducing the metastatic potential of breast cancer. I also discuss future studies aimed at identification and characterization of calpain-1 and calpain-2 specific physiological substrates with mechanistic relevance to the observed phenotypes and describe a biosensor to screen for allosteric inhibitors of calpain-1 and calpain-2.

abstract: M.Sc.


title: An Exploration and Experimental Test of a Generic Messaging Approach to the Canadian 24-Hour Movement Guidelines for Adults

contributor:
Latimer-Cheung, A. E.
Kinesiology and Health Studies

subject:
Health Promotion
Movement Behaviours
Health Messaging
Knowledge Translation
Self-Efficacy

abstract: Most Canadian adults do not meet current behaviour recommendations for physical activity, sedentary behaviour and sleep. Historically, movement behaviours were presented in isolation from one another, using complex and overwhelming thresholds outlining durations and intensity for optimal health. Generic messages encouraging small, but meaningful, behaviour change may be a better approach than thresholds through improving adults’ confidence to engage in optimal movement patterns. New integrated Guidelines providing evidence-based recommendations for Canadian adults’ movement behaviours over a 24-hour day are forthcoming. Public facing messages complementing the scientific recommendations to promote engagement amongst adults are needed, and generic messages may be a gateway to encourage adults’ confidence to meet the Guidelines. Grounded in Social Cognitive Theory, this thesis aimed to determine and experimentally test a generic tagline for the Guidelines and build support for generic messaging among health behaviour interventions. Two studies were completed online. In Study 1, Guideline end-users and stakeholders (NPhase1=774; NPhase2= 996) ranked a series of taglines based on whether the messages fostered Guideline self-efficacy beliefs. In Study 2, adult Guideline end-users (N=249) completed pre-, post- and two-week quantitative surveys following exposure to generic or threshold Guideline promotional materials. In the first study, a chi-squared test of independence confirmed the generic tagline “Move More. Sit Less. Sleep Better.” was favoured as self-efficacy boosting, χ2(1) = 142.4, p < .001. In the second study, hierarchal linear regressions predicting adults’ confidence to meet the Guidelines revealed an activity status by experimental condition interaction, F(4, 192) = 52.14, p < .05, ßGeneralTask = -.18,  F(4, 192) = 43.06, ßScheduling = -.15, p < .05.  Post hoc analyses indicated low active adults exposed to generic messages had greater confidence to meet the Guidelines compared to low active adults exposed to threshold messages. Additionally, message processing was greater among adults exposed to the generic materials than the threshold materials, F(3, 243) = 3.34,  p < .05. The findings emphasize that generic messages may be advantageous for promoting adults’ confidence to meet movement guidelines. This work presents considerations for researchers and health promoters aiming to develop appropriate messages for health behaviour engagement among Canadian adults.

abstract: M.Sc.


title: Illuminating Community Experience and Perception of Modern Treaty Implementation Through Photovoice: Photography and Stories From Huu-ay-aht First Nations

contributor:
Castleden, Heather
Geography and Planning

subject:
Geography
Geography of Modern Treaty
Canadian Treaty History
Huu-ay-aht
Nuu-chah-nulth
Modern Treaty
Community Based Participatory Research
Photovoice

abstract: Canada is currently operationalizing reconciliation efforts that stress the establishment of respectful and just relationships between Indigenous peoples and provincial and federal governments. British Columbia (BC) is unique among Canadian provinces and territories, given its lack of historical treaty agreements with Canadian governments. In April 2011, Huu-ay-aht First Nations joined four other Nuu-chah-nulth First Nations to begin implementation of the Maa-nulth Final Agreement (also known as the Maa-nulth Treaty) with BC and Canada, one of only three modern treaties that had been negotiated in the province at that time. Through narrative analysis of a case study using photovoice and participant observation involving 33 participants, I explore the experiences and perceptions of Huu-ay-aht citizens regarding the early years of treaty implementation. Modern treaties are often theoretically criticized for being extensions of assimilative and colonial processes. However, empirical findings from this community-engaged study exemplify positive change, or the potential for change, and enhanced community autonomy, as seen and experienced through increases in control over Treaty Lands. Participants’ data show that this control is effectively counteracting some of the impacts of dependency and suffering created by decades of destructive and racist Canadian federal and provincial government policies, structures, and services. Structural, environmental and health concerns that remain as treaty implementation continues are also discussed. This case study contributes to a better understanding of the experiences and perceptions of Indigenous peoples implicated in modern treaty relationships, experiences and perceptions that (as yet) are not adequately represented in the literature.

abstract: M.A.


title: Composition of Transformations in Feature-Based Registration

contributor:
Ellis, Randy
Computing

subject:
Computer Vision
Point Clouds
Registration
Computer Assisted Surgery
Oriented Points
Expectation-Maximization
Medical Imaging

abstract:
Accurate registration of medical images is crucial to the successful deployment of computer assisted interventions or surgical navigation systems.  Nonrigid registration techniques are important when considering soft tissues or other deformable anatomies, inter-individual registration, or the use of atlases or template objects; however, nonrigid transformations must be constrained in order to ensure that the resulting mappings are anatomically feasible.  Application-specific models of deformation---designed to capture statistical relationships, or functional constraints of the anatomy of interest---are one way of constraining nonrigid deformations while maintaining the generalizability of the model.  In most cases however, the use of these application-specific models is complicated by the need for customized registration algorithms.

This work facilitates the use of application-specific models of deformation by proposing a general algorithm to allow sets of points or oriented points to be registered through arbitrarily composed sets of transformations.  Simple transformations can, in principle, be combined into more complex models specific to the anatomy under consideration.  The algorithm is designed to be modular: by leveraging the power of modern statistical framings of the point set registration problem, arbitrarily composed sets of transformations can be optimized, requiring only that each transformation has a known solution to a particular standard form of equation.

The basic approach is developed first in the context of an actual medical imaging problem: the registration of intraoperative cardiac ultrasound, and preoperative CT scans.  The ultrasound images are processed by registering a model through a hierarchical transformation using a novel generalized expectation-maximization approach.  This approach is extended to a general algorithm for the registration of point or oriented point sets through arbitrarily composed transformations, and a class of heuristic modifications are proposed and experimentally examined.  The algorithm is shown to produce promising results in both synthetic data experiments examining robustness to noise and outliers, and in an application to actual cardiac imaging data.  Ultimately, it is hoped that this work can aid researchers in constructing application-specific solutions to the problems they face and help improve registration accuracy in a variety of difficult medical imaging problems.

abstract: PhD


title: Temporal Stability of Cortisol Reactivity to Stress and Reward Responsivity in the Context of Depression and Anhedonia

contributor:
Harkness, Kate
Psychology

subject:
Depression
Anhedonia
Biological Stress Reactivity
Reward Responsivity

abstract: Theoretical and empirical work suggest that reactivity to stress and responsivity to reward are correlated domains of functioning, and that dysfunction in the stress and reward systems may underlie Major Depressive Disorder (MDD). The goals of the current study are to examine: (1) the longitudinal stability of cortisol reactivity to stress and behavioural reward responsivity; (2) longitudinal changes in cortisol reactivity to stress and behavioural reward responsivity; (3) moderating variables (depression symptoms, anhedonia symptoms, sex, childhood maltreatment, and life stress) in the stability and change of cortisol reactivity to stress and behavioural reward responsivity; and (4) the co-variation of cortisol reactivity to stress and behavioural reward responsivity over time. The current study includes 77 adults (52 with a lifetime history of MDD, 25 never-depressed) who were well-characterized in terms of their diagnostic and symptom profiles, and who participated in a laboratory stress challenge (the Trier Social Stress Task; TSST) and a computerized Probabilistic Reward Task (PRT) at two time points approximately six months apart. My results indicated that there was general stability in both cortisol reactivity to stress and reward responsivity over time (i.e., Time 1 scores significantly predicted Time 2 scores); however, stability was also associated with moderating variables. There were also changes in both cortisol reactivity and reward responsivity over time (i.e., increases or decreases at a group level); however, these changes were related to moderating variables. Finally, my results suggested that cortisol reactivity to stress and behavioural reward responsivity co-varied over time. This is the first study to examine the longitudinal stability of both cortisol reactivity to a social evaluative stress task and behavioural reward responsivity. Further, this study is the first to examine how cortisol reactivity and reward responsivity co-varied across two time points. My findings provided an important foundation in identifying factors that may be relevant in altering the stability of cortisol reactivity and reward responsivity, and suggested that changes in anhedonia symptomatology and exposure to stressful life events may be particularly relevant to the stability of the stress and reward systems over time.

abstract: PhD


title: Labour Geographies and the Digital Transformation of Work: Self-Employment, Collective Organizing, and the New York Taxi Workers Alliance

contributor:
Mullings, Beverley
Holmes, John
Geography and Planning

subject:
Labour Geography
Taxi
Collective Organizing
Gig Economy
Uber
Digital Labour Platform

abstract: Built around a collection of four manuscripts, this dissertation focuses on the collective organizing strategies of non-standard workers. Multiple chapters focus on a case study of the New York Taxi Workers Alliance, a union without collective bargaining rights, and its effort to improve working conditions in the for-hire transportation industry and to redistribute economic resources to drivers. Drawing on mixed methods including participant action research, interviews, and surveys, the research took place amidst industry transformation brought on by the introduction of app-based dispatching services, such as Uber and Lyft. Several of the manuscripts examine the effects that app-based dispatching services have on work quality, the for-hire vehicle industry generally, and on for-hire drivers’ collective organizing strategies. Engaging with disciplines including labour geographies and industrial relations, this dissertation presents local regulatory infrastructures as an adequate venue for traditional taxicab and app-based drivers to address their collective interests and to achieve enforceable improvements in working conditions and wages.

abstract: PhD


title: Characterization of Transcription Factor-Coactivator Complexes in Acute Lymphoblastic Leukemia

contributor:
Smith, Steven
LeBrun, David
Biomedical and Molecular Sciences

subject:
Hematopoiesis
Lymphocyte
Acute Lymphoblastic Leukemia
Protein-Protein Interaction
CBP/p300
Transcription Factor

abstract: Acute lymphoblastic leukemia (ALL) is a cancerous hematological disorder originating in B-lymphoid progenitor cells. In 5% of ALL cases, the oncogenic transcription factor E2A-PBX1 is expressed as a result of the chromosomal translocation 1;19. E2A-PBX1 contains the activation domains of E2A and most of the PBX1 protein, including the DNA-binding homeodomain. These structural features suggest a hypothetical oncogenic model in which E2A-PBX1 binds DNA, recruits transcriptional co-activators by means of the activation domains and induces ALL through deregulation of PBX1 target genes. This transcriptional control is, in part, mediated by the recruitment of the transcriptional coactivator CBP/p300. Indeed, previous studies have shown that E2A-PBX1-mediated oncogenesis requires direct binding of E2A-PBX1 to CBP/p300. However, the transcriptional targets of this complex remain unknown. Additionally, as t(1;19)-mediated ALL is derived from B-lymphoid progenitors, we propose that E2A-PBX1 may be localizing to B-lymphopoietic enhancers bound by the master B-lymphopoietic transcription factors EBF1 and wild-type E2A, perturbing enhancer function and contributing to the development of ALL. The purpose of this thesis was to: 1) identify genomic regions where E2A-PBX1 binds; 2) assess whether other transcription factors are associated with the E2A-PBX1:CBP/p300 complex and further elucidate the structural and biophysical characteristics of those interactions; and 3) develop and characterize an inhibitor to the E2A-PBX1:CBP/p300 complex as a potential therapeutic for ALL. Using chromatin immunoprecipitation followed by massively parallel DNA sequencing (ChIP-seq), we identified over 3700 E2A-PBX1 binding sites in an ALL-derived cell line. We show that E2A-PBX1 recruits CBP/p300 to roughly 50% of its binding sites and localizes with CBP/p300 to consensus sequences bound by EBF1 and wild-type E2A. Using structural and biophysical methods, we characterize interactions between the TAZ2 domain of CBP/p300 and the activation domains of E2A-PBX1 or E2A and EBF1. The structural and ChIP-seq data suggest an additional E2A-PBX1 binding model in which E2A-PBX1 localizes to B-lymphopoietic enhancers by indirectly interacting with EBF1 and wild-type E2A with CBP/p300 as a mediator. Lastly, we developed a disruptor peptide that can bind the KIX domain of CBP/p300 with nanomolar affinity which disrupts E2A-PBX1:CBP/p300 complex formation in ALL cells and downregulates E2A-PBX1 target genes in vivo.

abstract: PhD


title: Photoisomerization of Triaryl Boron Functionalized Stilbene Derivatives and Synthsis of Pentacoordinate Boron Compounds

contributor:
Wang, Suning
Wu, Gang
Chemistry

subject: Boron Chemistry Photoreaction Synthesis

abstract: Studies of photoreactive organoboron compounds have progressed rapidly in the last decade. This thesis reports on the discovery of new photochemical and photoluminescent properties of triaryl boron compounds and the attempt to synthesize pentacoordinate boron based \pi-conjugated systems with potential multi-responsive properties. In particular, we investigated the photoisomerization of boron-containing stilbene analogues and discovered a new multi-step photoisomerization process that leads to the formation of a rarely reported backbone containing three fused five-membered rings. This unusual reactivity was believed to be due to a special type of HOMO-LUMO interactions that are previously unknown in the literature. While the attempted synthesis of a series of new pentacoordinate boron compounds was unsuccessful, we presented in this thesis some preliminary results and discussed potential synthetic routes.

abstract: M.Sc.


title: Investigating Relationships among Chinese High School Students’ Self-Assessment of English Skills, English Proficiency, and Their Perceptions towards Self-Assessment

contributor:
Cheng, Liying
Education

subject:
Self-Assessment of English Skills
English Proficiency
Perceptions Towards Self-Assessment

abstract:
It is widely accepted in education that self-assessment improves students’ learning and achievement, particularly in regard to foreign language acquisition. English curriculum standards for senior high school in China has been addressing the importance of cultivating students’ self-assessment ability since 2001. Although there is a robust research literature about self-assessment in other countries, the role that self-assessment plays in students’ learning has not been sufficiently investigated in the context of English teaching and learning in China.
    To address this research challenge, this thesis investigated the relationships among Chinese high school students’ self-assessment of English skills, English proficiency and their perceptions towards self-assessment.
    A self-assessment questionnaire was utilized in this research. As the indicator of students’ English proficiency, their English examination score, including the scores of listening and speaking, reading and writing, was also collected. Participants included 302 students from one high school in Guangzhou, China. Statistical analyses included One-Sample t-test, Pearson correlation analyses, One-way ANOVA, and multiple regression analyses.
    The results of the research revealed four overarching findings. First, students were able to self-assess their strengths and weaknesses in reading, writing, and listening and speaking skills, and they perceived that self-assessment was a useful tool to help improve their English. Second, there was a significant and positive correlation between students’ self-assessment of English skills and their English proficiency, which only existed in high-level students, not in students of intermediate or low level. Third, there was a significant and positive correlation between students’ self-assessment of English skills and their perceptions towards self-assessment, with the variables of appraisal function and habitual action having the significant and positive power in predicting students’ self-assessment of English skills. Finally, a significant and negative correlation was found between students’ English proficiency and their perceptions towards self-assessment with only the variable of appraisal function having the significant and positive power in predicting students’ English proficiency.
    This study could add empirical evidence to deepen educators and school teachers’ understanding on Chinese high school students’ self-assessment of English skills and their perceptions towards self-assessment.

abstract: M.Ed.