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Investigations into the O₂-mediated mechanism of microvascular blood flow regulation in vivo: carbon dioxide concentration dependence and role of adenosine triphosphate sensitive potassium ion channels
No full textMicrovascular blood flow regulation is paramount as the microvasculature provides nutrients to the tissues of the body while removing waste products. When blood flow is dysregulated, nutrient delivery and waste removal are impaired. Research into methods for blood flow regulation of the microvasculature and the conducted signaling that occurs to allow the environment of the capillaries to adequately respond to the changing conditions in the blood and in the tissue is ongoing. Carbon dioxide, a main waste product, is believed to influence conducted signaling and the oxygen-mediated mechanism of blood flow regulation while adenosine triphosphate sensitive potassium (KATP) channels are also believed to be involved in these processes. Using intravital video microscopy and a gas exchange chamber with a gas permeable membrane, the microvascular environment of the extensor digitorum longus can be controlled and altered to allow for investigations into the oxygen mediated mechanism of blood flow regulation and conducted signaling. It was found that carbon dioxide influenced the dynamics of the oxygen-mediated mechanism of blood flow while KATP channels are seemingly uninvolved in the oxygen-mediated mechanism of blood flow regulation in the extensor digitorum longus muscle of rats. These findings will guide future microvasculature blood flow regulation research
The ethics of (intersex) avoidance
No full textThis thesis critically examines the ethical implications of using Pre-Implantation Genetic Diagnosis (PGD) to avoid the birth of intersex children, challenging the arguments presented by Robert Sparrow in "Gender Eugenics? The Ethics of PGD for Intersex Conditions" (2013). Sparrow defends the use of PGD for intersex avoidance to promote the future child's well-being. Still, this work contends that such practices are ethically indefensible and perpetuate harmful societal narratives. First, it employs the Expressivist Critique to illustrate how reproductive decisions in the context of intersex avoidance perpetuate the devaluation of intersex lives, challenging the notion of ethical neutrality in such practices. Second, exploring intersex avoidance through the lens of Donna Haraway's Cyborg Feminism, the thesis highlights the cultural and psychological implications of rejecting intersex identities and reinforcing binary gender norms. Third, it examines parental ethics, advocating for an approach to parenting that embraces openness while emphasizing the ethical dimensions of reproductive decisions. The thesis ultimately calls for a more inclusive understanding of intersex variations, urging a re-evaluation of societal and ethical frameworks to foster a diverse and accepting community.Includes bibliographical references (pages 146-152
Individual differences in behaviour and space use at multiple scales are consistent throughout the life cycle of hydrobates leucorhous
No full textIndividual consistency of behaviour and space use has been observed in many contexts and across taxa and has important evolutionary and conservation implications. Consistency leads to predictability, which enhances the effectiveness of conservation plans that are based on data collected in the past. In addition, consistent behaviour relates to life history traits such as survival and reproduction and can inform which individuals in a population are more productive and more at risk. Traditional conservation strategies consider among- and within-individual variation as noise, yet ignoring this variation can lead to systematic misrepresentation of part or all of the population. Among-individual variation and within-individual consistency may be a particularly important consideration for studies of seabirds due to their long lives, vast annual ranges, and variation in life history strategies and home ranges among individuals within a population. The Leach�s Storm-Petrel (Hydrobates leucorhous) is a prime example of this; these birds can live for more than 30 years, and their home ranges cover much of the Atlantic and Pacific Oceans. I studied inter-individual variation and individual consistency in the behaviour and space use of Leach's Storm-Petrels throughout their annual cycle. I further explored the relationships of consistent behaviour and space use with reproductive success and risk exposure. I first measured the response to handling at the burrow as a measure of animal personality. Second, I used passive integrated transponder tags to investigate parental behaviour at the burrow during the breeding season. I next increased the spatial scale and investigated consistency in foraging behaviour and space use at sea using GPS trackers, and finally I investigated consistency of migratory space use and risk exposure using GLS. For all four behaviours, I measured a subset of individuals across at least two different years (up to a maximum of 7 years apart) to measure inter-annual consistency. Leach's Storm-Petrels exhibited consistent behaviour and space use both within and across years at all scales; they exhibited repeatable boldness, parental behaviour, foraging space use and behaviour while foraging, and migratory space use. Consistent behaviour during the breeding season predicted reproductive success, and space use during foraging and migration was associated with exposure to offshore oil platforms, windfarms, and oil spills. My results illuminate the importance of individual differences for understanding variation in reproductive success and risk exposure, and the consequences of this variation for populations
Design and optimization of low-power SAR ADC
No full textIn the era of Internet-of-Things (IoT) and wearable biomedical technologies, the need for ultra-low-power analog-to-digital converters (ADCs) is increasingly critical. These systems often interface with low-activity signals such as electrocardiograms (ECG), voice, and ultrasonic data, which exhibit sparse changes over time. This thesis presents a set of novel design methodologies for energy-efficient successive approximation register (SAR) ADCs that leverage the statistical characteristics and temporal correlations of low-activity signals to reduce power consumption across the comparator, digital-to-analog converter (DAC), and digital control logic.
To minimize comparator activity, various search schemes were developed. These include adaptive search algorithms based on first- and second-order differences, as well as machine-learning (ML) and reinforcement-learning (RL)-based methods. The proposed algorithms dynamically reduce the number of bit comparisons from the fixed N cycles in conventional N-bit SAR ADCs to a range between 2 and N, resulting in up to 79.74% reduction in comparator activity compared to the monotonic method, while maintaining the same conversion accuracy.
To further reduce DAC switching energy, this thesis introduces a novel DAC update scheme specifically designed for low-activity signals. These approaches achieve up to 88.88% reduction in switching energy compared to the monotonic method. In addition, a dedicated digital logic cell design using different techniques is proposed, reducing short-circuit power in the SAR logic and offering up to 34.77% improvement in digital logic energy efficiency. The proposed techniques were validated through MATLAB simulations, circuit-level implementation, and silicon measurements in a 0.18 ?m CMOS process. Measurement results from a fabricated 10-bit SAR ADC chip demonstrate a 70.05% reduction in comparator activity compared to the conventional monotonic approach. With a 5.6 kHz sinusoidal input, the ADC achieves an SNDR of 57.78 dB and SFDR of 67.06 dB. The total power dissipation remains below 0.54 ?W, with an additional estimated 0.22 ?W for the digital part, making it an ideal solution for always-on voice interfaces in battery-operated IoT and biomedical devices.
Overall, this thesis contributes a comprehensive suite of techniques for next-generation low-power SAR ADCs, balancing architectural innovation, machine learning intelligence, and circuit-level optimization
Optimal control strategies in epidemic models: analysis of community and traveler isolation strategies under resource constraints
No full textIn some regions, health authorities may implement an elimination strategy involving
public health measures that apply to travelers and community members to control
infectious disease spread. Optimal control theory consists of mathematical results
that apply to epidemiological models and describe control strategies that maximize
or minimize an epidemiologically-relevant quantity given constraints. The previous
work of Hansen and Day (2011) has characterized optimal controls involving community
isolation and vaccination with the objective of minimizing outbreak size. We
build on this previous work by considering epidemiological dynamics involving infection
importation, traveler isolation as a control measure, and by characterizing the
optimal controls in the terminology of public health. We discuss a related theorem
from Hansen and Day (2011) in the context of our extensions of their modelling. We
numerically implement control measures and characterize the resulting epidemiology
and resource use as an elimination, mitigation, or circuit breaker strategy. We find
that which public health strategy the implemented control is characterized as depends
on parameter values that can be interpreted as corresponding to regional conditions.
When resources are not limited, the implemented strategy corresponds to: an elimination
strategy, when the maximum daily isolation rate is high and the importation
rate is low; and a mitigation strategy, when the maximum daily isolation rate is low
and the importation rate is high. When resources are limited, the implemented strategy
corresponds to a circuit breaker strategy. No previous studies have provided a
general framework whereby elimination, mitigation, or circuit breaker strategies can
arise as solutions to optimal control problems for different epidemiological and resource
use-related parameters, and such results show that different infectious disease
control strategies can be optimal in different regions.Includes bibliographical references (pages 60-69
Simulation of autonomous surface vehicles using smoothed particle hydrodynamics
No full textThe study of Autonomous Surface Vehicles (ASVs) is a growing area of research as
traditional methods of ocean observation and mapping are expensive. Oceanographic
buoys require buoy tenders with appropriate lift capacity, and research vessels are
high-cost assets that require an experienced and knowledgeable crew. ASVs are attractive
as they can be operated from a distance, can be smaller than traditional
research vessels, and are able to navigate to areas of interest, unlike moored buoys
while often providing equivalent oceanographic data with lower operational costs.
Unfortunately, the development of ASVs is costly. Field trials often require teams
of people, chase boats, sensors to monitor environmental conditions, and operations
centres. Model testing also requires specialized facilities and experienced personnel.
Simulations can be a complementary and cost-e ective approach to assist in the
development of ASVs. Simulations accelerate the development of new hull designs
and testing of algorithms before the use of scale or eld testing. This thesis focuses
on the simulation of ASVs with the use of Smoothed Particle Hydrodynamics (SPH).
SPH is a computational
uid dynamics method that discretizes the
uid into a set
of particles which use a Lagrangian coordinate system. Although SPH was originally
developed to solve astrophysics problems, it is rapidly growing in popularity in the
ocean engineering elds. This thesis explores the use of SPH to simulate ASVs in
water to help understand the relationship between ASVs dynamics and the dynamics
of the water. A challenge to ASVs development is producing algorithms that are
robust to environmental disturbance. This thesis also explores methods for developing
numerical wave tanks so that ASVs can be tested under environmental disturbances
to help developers validate control algorithms before scale or eld testing
Stitching sustainability: an autoethnographic exploration of fashion practices in western Newfoundland and southwest Nigeria
No full textThis thesis investigates sustainable fashion through an autoethnographic lens, drawing from the researcher's personal journey as a fashion entrepreneur in Nigeria and an immigrant entrepreneur in Newfoundland and Labrador, Canada. The central research questions ask first: How can sustainable fashion practices be adapted to Newfoundland's cultural, environmental, and economic context? And second: how can insights from Southwest Nigeria's sustainability models inform this adaptation? Anchored in comparative and reflexive inquiry, the study aims to (1) analyse the cultural and market dynamics influencing sustainable fashion in both regions, (2) evaluate opportunities and barriers in practice, policy, and perception, and (3) propose context-sensitive, community-driven fashion interventions. Hypotheses tested include: that culturally rooted sustainable fashion is more readily accepted by local communities, and that this can strengthen community engagement and cultural preservation in Newfoundland. Methodologically, the research integrates autoethnography with narrative analysis, participant observation, reflexive journaling, and thematic analysis. The analysis is framed by five emergent themes: fashion entrepreneurship, social significance of fashion, circular fashion, consumer behavior, and cultural perspectives. The thesis documents the founding of Bimpegold, a sustainable fashion initiative in Newfoundland, shaped by the researcher's Nigerian experiences and adapted to a setting with an aging population, limited tailoring culture, and abundant institutional support. Findings reveal that while Nigeria has a vibrant tailoring culture but limited systemic support, Newfoundland offers structured opportunities (e.g., funding, incubators) but suffers from fashion illiteracy and excessive clothing waste. The research demonstrates that sustainable fashion must be place-based and relational, grounded in cultural pride, economic resilience, and environmental responsibility. It concludes with recommendations for fashion education, policy support, and curriculum development, particularly for K−12 systems, positioning sustainable fashion not only as a movement, but as a model for ecological and social renewa
Investigation of protein kinase D3 (PKD3) and ARGHAP11A (MP-GAP) interaction: an epitope tag-based co-immunoprecipitation approach
No full textProtein interactions are fundamental to cellular signaling and regulatory pathways, driving diverse biological processes. This thesis investigates the potential interaction between protein kinase D3 (PKD3) and ARHGAP11A (MP-GAP) using an epitope tag-based co-immunoprecipitation approach. PKD3, a member of the protein kinase D family, is implicated in cell cycle regulation, cytokinesis, and cancer progression, while MP-GAP is a critical Rho GTPase-activating protein involved in cytokinesis. Given their roles, this study hypothesizes a functional relationship between PKD3 and MP-GAP in regulating cytokinesis via RhoA activity modulation.
To explore this interaction, a system was developed for the expression and detection of epitope-tagged PKD3 and MP-GAP in mammalian cells. Optimized protocols for cloning, protein expression, and immunoprecipitation were established. Despite validation of constructs and experimental conditions, co-immunoprecipitation experiments failed to confirm a direct interaction. Challenges such as low expression levels, nonspecific antibody binding, and potential transient or weak interactions were addressed.
These findings highlight the challenges inherent in studying transient or weak protein interactions, emphasizing the importance of leveraging complementary methods such as cross-linking or mass spectrometry to overcome experimental limitations. While no direct interaction was observed, this research provides insights into the complexities of PKD3’s regulatory functions in cytokinesis. It sets the stage for future studies aimed at unraveling its broader role in cell cycle regulation and its potential as a therapeutic target in cancer biology.Includes bibliographical references (pages 86-95
A study of social skills development in newcomer, bilingual kindergarten students
No full textThis study investigates the development of social skills in newcomer bilingual kindergarten students in Newfoundland and Labrador, Canada. It explores how these children develop social skills through interactions with their teachers, identifies barriers and facilitators in their development, and proposes ways to enhance educational settings to better support their social growth. The research addresses a central question: How do bilingual newcomer kindergarten-age children develop social skills? Sub-questions examine the factors that facilitate or hinder their social skills development in educational settings and how these environments can better support their social growth.
Employing a qualitative phenomenological methodology, data were collected through interviews with teachers and parents of bilingual newcomer kindergarten-age children, supplemented by classroom observations. Thematic analysis of parent and teacher interviews revealed several challenges affecting the social skills development of these children, including the impact of limited English proficiency, negative emotions they might experience, the difficulties faced by newcomer parents in providing adequate support, cultural differences that hinder smooth integration, and the lack of sufficient preparedness in educational settings to support their social skills development. Additionally, the findings highlight the support available to bilingual newcomer children, the strategies educators use to nurture social skills, the importance of family engagement, and the role of cultural sensitivity in promoting inclusivity in education. Classroom observations were used to assess how these findings align with real-world practices.
The study's findings offer valuable insights into how schools and educators can more effectively support the social development of bilingual newcomer kindergarten students. By fostering inclusivity, enhancing family engagement, and promoting cultural awareness, educational institutions can create more supportive environments that enable these students to thrive socially.Includes bibliographical references (pages 211-237
Psychophysiological responses to stride frequency manipulation in men and women
No full textThis study examined psychophysiological responses to stride frequency manipulation during walking in men and women. Nineteen healthy adults (11 men, 8 women) completed two sessions: familiarization session (session 1) during which the preferred stride frequency (PSF1) and its corresponding speed (PWS1) were determined, and experimental session (session 2) that consisted of participants walking at four 15-minute treadmill counterbalanced conditions: the preferred stride frequency measured in Session 1 and being imposed in session 2 called PSF2, new PSF measured in Session 2 (PSF3), and ±10% deviations from PSF2. Oxygen uptake (V̇O₂), affective pleasure (Feeling Scale), arousal (Felt Arousal Scale), perceived effort (RPE) and heart rate (HR) were measured. Repeated-measures ANOVA revealed significant main effects of stride frequency on V̇O₂ (p < 0.001), feeling scale (p < 0.05), and RPE (p < 0.05). Planned contrasts showed that PSF3 elicited lower V̇O₂ (p < 0.01, medium to large effect size), lower RPE (p < 0.05, medium to large effect size) and higher positive pleasure (p < 0.05, medium effect size) compared to the ±10% deviations. Planned contrasts showed that PSF3 compared to PSF2, elicited lower V̇O₂ (p < 0.05, medium effect size), lower RPE (p < 0.05, medium effect size) and higher positive pleasure (p = 0.05, medium effect size). Heart rate recovery was faster in women (p < 0.05), but no sex-condition interactions emerged for any primary outcomes (all p > 0.05). Findings demonstrate that preferred stride frequency minimizes energy cost and psychological responses during walking, with no difference between men and women