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The out-of-pocket costs and influencing factors associated with emergency department use for patients in Newfoundland and Labrador
No full textResearch on out-of-pocket costs (OOPC) has not been thoroughly studied in a Canadian
context within the emergency department (ED), where visiting volume and length of
stay are increasing. The objective is to identify OOPC in Newfoundland and Labrador
(NL) EDs, determining the proportion, severity, and forms of OOPC and the covariates
that influence OOPC in the ED. Using a cross-sectional study, 807 visitors were
surveyed regarding OOPC. One of four patients (25%) reported OOPC for an ED visit
and average OOPC was 793.35). After controlling for other potential
confounders, patients visiting urban hospitals (OR=1.79, 95% CI, (1.26-2.55)) or
waiting 4+ hours (OR=2.13, 95% CI, (1.24-3.69)) were more likely to report OOPC for
an ED visit. Patients visiting urban hospitals (5.86, 95% CI, (1.25-27.5)) were also more
likely to report higher levels of OOPC.
Implications: These findings indicate the importance of reducing wait time in the ED.
Enhancing ED efficiency and reducing wait time has the potential to reduce the financial
burden on society. By reducing wait time, the healthcare system can mitigate costs and
improve health outcomes for patients and the broader community.Includes bibliographical references (pages 62-71
Cultural bridges in immigrant homes: Jamila Mohammed's family preservation of identity through the "Coffee Room"
No full textIn this thesis, I investigated how immigrants preserved their heritage and developed their identity in the diaspora through cultural objects, such as handmade baskets, coffee rituals, and memories. My research centered around the coffee room in the home of Jamila Mohamed, an Ethiopian immigrant living in St. John's, Newfoundland. I explored Jamila's motivations for designing the coffee room, which resembles those in her hometown, Harar, and uncovered deeper meanings of the room for family members. My research focused on the role these cultural rituals play in a person's everyday life, differing from previous studies on the Ethiopian diaspora which examine how traditional coffee rituals help strengthen ties within communities. I investigated how the coffee room served as a cultural bridge, connecting Jamila and her children to Harar and protecting them from feeling disconnected from their homeland or isolated in their new country through folkloric theories of material culture, performance, and gender. Through the coffee room, Jamila and her family practice their rituals together, as well as share them with non-Ethiopian friends. They strengthen their connections to their new community in Canada, not by abandoning or losing their culture, but through pride by actively participating and adapting their heritage
Fractional operators and their applications in image processing
No full textThe boundedness of operators and capacity theory are fundamental topics in harmonic analysis.
In this thesis, we focus on studying the properties of fractional operators, particularly
the fractional Laplacian and Riesz potential, along with their associated capacities. We then
extend these theoretical results to develop new models in image processing.
Image decomposition plays a crucial role in image processing. Before conducting further
analysis or modifications, such as detail enhancement or image composition, it is often
necessary to decompose an image into different components, allowing for the independent
manipulation of geometric features. As a specific case of this, image denoising
involves removing unwanted noise while preserving essential details. Given the global nature
of fractional operators compared to traditional derivatives, we propose several models
for image decomposition and image denoising, utilizing both the partial differential equation
(PDE) method and the variational method. These models are supported by numerical
simulations to demonstrate their effectiveness. Chapter 2 introduces three PDE-based models
involving the fractional Laplacian and Riesz potential for image denoising, along with
proof of the existence of solutions. Chapter 3 builds on interpolation techniques to propose
(BV; ˙W ᵅ,ᵖ,∞)-based model for image decomposition. Chapter 4 establishes the trace
principle of the Poisson-Bessel potential, a solution to the well-known Caffarelli-Silvestre
harmonic extension, from the fractional Hardy-Sobolev space to the weak Lebesgue space,
as well as its limiting case. Based on these results, we propose (Hᵅ,¹, Lq ) and (Hᵅ,¹; log)
decomposition models. Chapter 5 characterizes the fractional wave potential derived from
the Cauchy problem for time and space fractional partial differential equations and explores
its applications in wave function theory and image processing. Finally, this thesis concludes
with a summary of our findings and potential directions for future research
Eversible rings and zero-divisors
No full textThis thesis centers on the study of eversible rings, a class of rings in which every onesided
zero-divisor is necessarily a two-sided zero-divisor. The concept of eversibility
generalizes the idea of reversibility and offers a new perspective on the structure of
noncommutative rings. To motivate this study, Chapter 1 provides a historical and
conceptual overview of zero-divisors and their significance in both commutative and
noncommutative settings. Chapter 2 introduces some standard rings such as directly
finite rings, von Neumann regular rings, trivial extensions and skew polynomial rings,
which lay the groundwork for the main investigation. In Chapter 3, the focus shifts
to the study of zero-divisors and eversibility in specific ring contexts, including formal
triangular matrix rings, upper triangular matrix rings, polynomial rings and formal
power series rings. The final section of Chapter 3 critically addresses several incorrect
results from previous studies on eversibility. Through carefully constructed counterexamples,
the thesis disproves these erroneous claims, further refining our understanding
of the conditions under which eversibility holds in these contexts
Net effects: nationalist-capitalist hegemony in the hip hop-basketball paradigm
No full textIn this thesis, I investigate the sociocultural, political, and economic implications of basketball’s soundscape across various “arenas”—both real and imagined. I begin by examining media representations of the sport in contemporary and historical movies and music before shifting focus to how music and sound help shape performance events associated with the Toronto Raptors Basketball Club. Central to the analysis is the hip hop-basketball paradigm, through which I argue that basketball’s soundscape works to uphold a nationalist-capitalist hegemony. Introducing a methodological approach I call just listening, which emphasizes both intensely focused and ethically grounded listening practices, this thesis integrates ideas from the critical study of music, sound, and sport; sound studies and acoustic ecology; performance studies and its precursors; and theories of musical experience and phenomenological ethnomusicology to highlight how basketball’s aural dimensions—its characters, contexts, and contents—are shaped by, and respond to, broader sociocultural, political, and economic forces. Framed as a political act, this approach seeks to bridge individual and collective experiences. Through its application, I interrogate how soundscapes impact both situated and large-scale social contexts, offering a way to critique their intended and unintended outcomes—that is their net effects. Analyzing the practices, protocols, techniques and technologies that mediate sound and music, and the meanings, values, and uses ascribed to them by individuals and groups, my work in this thesis examines the meaningful experience of basketball’s soundscape, gleaning insights from ethnographic work with key stakeholders in Toronto’s professional basketball community, such as artists, fans, technicians, executives, and members of the media. Drawing on participant observation conducted in Toronto from 2018–2023, this thesis highlights the interplay between culture and commerce, examining how basketball’s acoustic environment helps cultivate individual and collective identity and mediate broader sociocultural, political, and economic ideas
Households’ willingness to install water meter case study: Corner Brook, Newfoundland and Labrador
No full textWater resources are essential for socioeconomic growth, ensuring human survival, and play an integral role in sustainable development (UN Water, 2015). Water resources benefit societies in a variety of forms and include advantages of a commodity nature in the contexts of industry, agriculture, and residents (Young & Loomis, 2014). As income rises and populations expand, water usage also grows to meet the demands of agriculture, industries, and households alike. This puts pressure on the limited freshwater reservoirs around the world (Watts et al., 2015). With climate change underway, temperatures will change, rainfall will become less predictable, and water systems may face challenges, so it is important for communities to prepare for what lies ahead (Watts et al., 2015). Such shifts increase the potential for socioeconomic and environmental disruptions and significantly impact the management and planning of water resources in the future (Gleick, 1989). In the City of Corner Brook, NL, water usage is not directly metered, and residents are not charged based on the amount of water they consume. Instead, the residents of Corner Brook pay an annual water and sewage tax, which is included in the property tax receipt. In fact, Corner Brook residents do not pay their water bills based on their consumption levels, which may lead to negligence and over-consumption within the households, making the current approach environmentally unsustainable. A binary choice model is applied to determine what affects people’s willingness to install water meters, relying on survey data collected directly from residents. The results show that a few key factors make it more likely for people to consider installing a meter. For example, older residents, those who know how much installation costs, people awareness of NL’s high water use per person, and those who believe meters help conserve water were more open to the idea. On the other hand, some factors make residents less interested in adopting water meters. Families with more members saw meters as an added expense. People
with higher education levels may think that managing water conservation should be handled by the government, not individuals. Retired residents and those who are satisfied with the current water pricing system are also less likely to support installation. These findings highlight both the variables that encourage and discourage water meter adoption. Using these insights, policymakers could create strategies to get more homes to install meters, improving water use and solving water management issues in the city of Corner Brook.Includes bibliographical references (pages 140-171
Dissecting the role of prostaglandin E₂ EP2 receptor signaling in MCH neurons in sex-dependent modulation of anxiety, memory and hippocampal synaptic transmission under western diet
No full textMelanin-concentrating hormone (MCH) neurons are known to regulate energy balance, food intake, anxiety, memory, and cognition. Prostaglandin E₂ (PGE2) can depolarize these neurons via EP2 receptors under western diet (WD) conditions, which contributes to diet-induced obesity. To determine how WD-induced activation of MCH neurons affects other function of these cells, this research examined the sex- and diet-specific effects of EP2 receptor (EP2R) deletion in MCH neurons on anxiety-like behaviors, memory performance, and synaptic plasticity. Male and female mice with MCH neuron-specific EP2R knockout (KO) were assessed under chronic standard chow or WD conditions using behavioral assays and electrophysiological recordings. EP2R KO significantly reduced anxiety-like behaviors in male mice on a WD, evidenced by decreased thigmotaxis in the open field test, while differences in thigmotaxis were absent in all females and chow-fed males. In the novel object recognition test, male EP2R KO mice exhibited increased novel object preference under standard chow conditions compared to WD KO mice, while EP2R KO protected females from WD-induced memory impairments. Finally, electrophysiological experiments in transverse dorsal hippocampal brain slices revealed higher neurotransmitter release probability in female EP2R KO chow-fed mice, as well as an enhanced post-tetanic potentiation in chow-fed male EP2R KO mice compared to chow controls, while no changes were seen in long-term potentiation. These findings highlight the complex interplay between diet, sex, and EP2R signaling in MCH neurons. Thus, EP2Rs in MCH neurons may play a role in high-fat diet-induced changes in mood and cognitive function.Includes bibliographical references (pages 91-112
Role of Vitamin D receptor in regulating bone metabolism during lactation and post-weaning recovery
No full textReproduction in mammals invokes adaptive mechanisms to meet calcium requirements for each
fetus and nursing infant. In humans, intestinal calcium absorption doubles during pregnancy, while
skeletal resorption occurs during lactation. After lactation, intestinal calcium absorption and bone
formation increase, restoring the skeleton, yet the molecular mechanisms driving these changes in
skeletal metabolism remain unclear. Previous studies in our laboratory with mice lacking the
Vitamin D receptor (VDR) or the 25-hydroxyvitamin D-1 alpha hydroxylase (Cyp27b1) enzyme
essential for Vitamin D (calcitriol) synthesis suggested that calcitriol is not required for intestinal
calcium absorption and skeletal homeostasis during reproductive cycles. However, these studies
used Vitamin D-deficient mice maintained on a 2 % calcium-enriched “rescue diet”, which may
have influenced bone mineral content (BMC) and post-weaning bone homeostasis. Hence, the
primary aim of the present study was to clarify whether skeletal adaptations of Vdr null mice
during post-weaning phase do not require VDR or the “rescue diet”. Wild-type (WT) and Vdr null
mice were maintained on the “rescue diet” until the end of lactation, then shifted to a standard 1 %
calcium diet for post-weaning recovery. Virgin controls were similarly treated. BMC was assessed
using DXA, and cortical bone strength was measured by the 3-point bend test. Both genotypes
showed significant BMC loss during lactation, with greater loss in Vdr null mice. Post-weaning,
BMC increased in both, but Vdr null mice failed to fully recover BMC. Similarly, the 3-point bend
test results indicate that Vdr null mice did not fully recover their bone strength during the postweaning
period. In conclusion, the skeletal adaptations of Vdr null mice during post-weaning
recovery require either VDR or the “rescue diet”. Further studies are needed to identify factors
unique to reproduction, independent of VDR, that may influence skeletal turnover during postweaning
recovery
Integrated onboard chargers for electric vehicles
No full textThis thesis focuses on the development and analysis of integrated onboard charger designs for electric vehicles (EVs). This novel EV charging approach is done by incorporating the propulsion and charging systems into a single unit. A permanent magnet synchronous motor (PMSM) and an inverter from the propulsion system are reconfigured to serve as a coupled inductor and a power converter in the charging system. Hence, no additional components are needed to charge the EV battery. One incredible ability of this topology is the capability of the PMSM to remain still and generate no torque when being used as a coupled inductor to charge the battery. This is made possible because of the special characteristics of the motor and the control scheme deployed. Also, the integrated charger is designed to have a very minimal current ripple content at both the output and input sides. These special features of the proposed model, zero torque generation and minimal current ripples, have been proven mathematically in this thesis. Simulations are also done to confirm the results from the mathematical analysis, and also observe and analyze the various modes of operation of the charger. Finally, experiments are carried out on 960W and 3kW chargers to test and evaluate their performance, efficiency and robustness. The results of the experimental testing suggest that the proposed model offers a higher efficiency, high power density, reduced current ripples, and improved performance of integrated onboard chargers that can go a long way to improve the battery health of EVs
Advanced model predictive control and power conversion strategies for flux-switching permanent magnet synchronous machines
No full textModern electric drive systems, particularly in electric vehicles (EVs), renewable energy, aerospace, and
industrial automation, demand efficient power conversion and robust motor control. Flux Switching Permanent
Magnet Synchronous Machines (FSPMSMs) are gaining attention due to their high torque density, enhanced
thermal performance, and durable structural design. However, their nonlinear behavior, parameter fluctuations,
and susceptibility to external disturbances present significant control challenges. Conventional approaches like
Field Oriented Control (FOC) and PI controllers often fall short in maintaining optimal performance under
dynamic conditions.
To address these limitations, Model Predictive Current Control (MPCC) has emerged as a viable solution,
offering improved dynamic response, reduced torque ripple, and better current regulation. Despite its
advantages, MPCC's reliance on accurate system modeling makes it prone to uncertainties. This research
introduces a novel integration of Sliding Mode Control (SMC) into the speed loop, enhancing the system's
ability to reject disturbances and adapt to varying conditions. The proposed MPCC SMC strategy demonstrates
faster transient response, increased stability, and greater reliability, making it well suited for demanding
FSPMSM applications. The approach is validated through high fidelity simulations using OPAL RT
Technologies’ OP5707XG simulator. In addition to advanced motor control , a stable high voltage DC supply is
crucial for efficient FSPMSM operation. Many energy sources, such as batteries, fuel cells, and photovoltaic
(PV) panels, produce low voltage DC power, requiring an efficient step up converter for high performance
motor drives. Traditional boost converters face challenges like extreme duty cycles, high conduction losses, and
reduced efficiency, limiting their suitability. To address these issues, this research explores the Cubic Semi
SEPIC Converter (C³SSC), a novel high gain, non isolated DC DC topology capable of achieving ultra high
voltage conversion with moderate duty cycles, reduced switching losses, and improved efficiency. A laboratory
tested prototype of the C³SSC confirms its high gain capability and practical viability for power conversion
applications. While MPCC SMC ensures robust control of the FSPMSM, the C³SSC efficiently provides the
necessary high voltage DC supply, enabling stable, efficient, and reliable motor operation. This research
integrates advance d motor control with high performance power conversion, enabling next generation electric
drives for sustainable transport, automation, and renewable energy.Includes bibliographical reference