VictorJuiz/thesis huggingface dataset:
Stress, Strain, and Failure in Heterogeneous and Anisotropic Rock

Strain evaluation of various testing frames/devices indicated that they have significant impacts, lowering the expected E by up to 50%, leading to a correction factor, termed “system-compliance”, that is unique to the test systems and setups. Also introduced, is a novel approach for sub-core extraction relying on CNC milling, which has proven a success rate of about 85% in any direction to the bedding plane. This technique was used to plug and assess the mechanical anisotropy of heterogeneous, anisotropic, water sensitive shale. The mechanical test results varied with change in the bedding plane with the exception of the E when the bedding planes were perpendicular to the test direction.Numerically, models should be able to capture the heterogeneity of the rock sample being simulated. The grain based modelling (GBM) within the combined finite-discrete element method (FDEM) demonstrated its ability to predict more realistic microscopic and macroscopic response of rocks than conventional FDEM models. The explicit modelling of crack boundaries captured microscopic failure transition from along grain boundaries to coalescence along shear bands, dominated by intraphase cracks. GBM can also represent pre-existing cracks by specifically assigning friction and cohesion values along the grain-grain interfaces. The results of the simulation indicated that for rough fractures, the effect of fracture intensity was minor and was more predominant on both stress-strain curves and macroscopic strength properties for smoother fractures. Hydro-mechanical response ranges from the mechanical response due to the in-situ stress condition and how the rock fabric reacts to the additional stresses imposed by the injection fluid. In the true-triaxial experiments, the hydraulic fracture occurred perpendicular to the intermediate stress in a strike-slip fault regime along the plane of weakness. A new conceptual model is proposed to explain the failure processes, based on which the shut-in pressure corresponds to the magnitude of the principal stress perpendicular to the fracture plane. Other values of shut-in pressure are indicative of a complex fracture network. The resulting fracture network is greatly impacted by the fluid viscosity, with lower viscosity promoting the interaction with bedding planes and existing discontinuities.

Keywords: Geomechanics
Grain based model
Hydrulic Fracturing
Laboratory Testing
Rock Mechanics
True Triaxial Tests
Advisor: Grasselli, Giovanni
A Hetorogeneous Stack for a Re-configurable Data Centre

With the increase of heterogeneity in data centres, the scalability of such devices, from the perspective of both ease of development and performance has been more difficult. The work in this thesis introduces a heterogeneous development and deployment stack at scale, particularly in integrating FPGAs and CPUs. This stack is a series of abstraction layers, where these layers can be swapped for different devices at the lowest level (we demonstrate this with CPUs and FPGAs), and different application domains at a higher level. End-to-end we present the translation of an application into hardware IP cores, to partitioning across devices, down to implementing on multiple FPGAs and CPUs. We also present the applicability of this heterogeneous stack for large scale applications through a large machine learning application. Through the use of multiple abstraction layers we have increased productivity and increased performance by unrolling our application across more devices at scale.

Keywords: Artificial Intelligence
Big Data
Computer Hardware
Data Centers
FPGAs
Networking
Advisor: Chow, Paul
Structuring Horizontal Accountability in Ontario’s Health Care System

Background: In health systems comprised of independent health care organizations, the structuring of integrated delivery systems relies on organizations structuring horizontal accountability (HA) with one another. Despite this requirement, we know very little about how this is achieved. While scholars acknowledge that HA should exist as complementary to an organization’s vertical accountabilities, research has found that the structuring of HA can be disrupted by strong vertical accountabilities. This research seeks to understand: how can HA be structured within a system historically reliant on vertical accountabilities?Methods: This was an embedded, multi-case, case study research design, utilizing two Ontario-based cases. I utilized multiple qualitative methods with semi-structured interviews with administrators and governors as a primary source of data collection. Drawing on definitions of accountability in the public administration literature and Bovens (2010) and Dubnick and Frederickson’s (2010) concepts of accountability as a mechanism and as a virtue, I developed a preliminary conceptual framework that would guide this research. The focus was exploratory with goals of analytic applicability, generalization, and the expansion of theory. Results: Where organizations are compelled to structure HA, they will structure HA with contingencies that maintain their independence. For HA to be successful, it must be structured in a way that maintains its virtues while also institutionalizing aspects of HA that codify the interdependence of the partners. Actions and behaviours from the principal and governors, and participant willingness to tackle various tensions resulting from the historical environment, will all be core to establishing a facilitative environment for HA. Democratic, political, clinical, and community dimensions of accountability are well suited to HA whereas high degrees of funding, performance, and bureaucratic forms of accountability may determine whether HA will be replaced by a hierarchical scenario. Conclusion: This research adds to the literature by considering necessary processes, mechanisms, and environments for structuring HA and presents conceptual and analytic frameworks that can be utilized by administrators, policy makers, and researchers. This comprehensive approach is important as the presence of mechanisms alone have proven to be insufficient to the successful structuring of HA relationships (Addicott & Shortell, 2014; Andersson & Wikström, 2014).

Keywords: Accountability
Healthcare
Horizontal accountability
Inter-organizational network
Organizational accountability
Advisor: Marchildon, Gregory P
The Role of Oxygen and Oxygen-Dependent Enzymes in Protein Folding, Metabolism, and Redox Homeostasis

Low levels of oxygen (hypoxia) in solid tumors contributes to therapy resistance and poor patient prognosis. How the cells in the tumor microenvironment (TME) adapt to hypoxia at a transcriptional, epigenetic, and translational level has been extensively explored. Here, we provide a comprehensive review on how molecular signaling in hypoxia represents an intricate, coordinated response triggered by oxygen dependent enzymes. Our work also highlights the lack of understanding of the requirement for oxygen in protein folding and the biological roles of an oxygen dependent enzyme, 2-aminoethanethiol dioxygenase (ADO). Secreted proteins contribute to aggressive cancer phenotypes in the TME. These secreted proteins are thought to utilize an oxygen dependent mechanism for disulfide bond formation required for proper folding, which represents a paradox when they are expressed under hypoxic conditions. Here we confirm the existence of oxygen independent pathways for disulfide bond formation. For the first time we demonstrate that key hypoxia-induced proteins such as vascular endothelial growth factor (VEGF-A) and carbonic anhydrase 9 (CA9) remain fully competent at disulfide bond formation in the absence of oxygen, supporting their efficient expression in hypoxia. This work highlights that the ability of individual proteins to undergo protein folding in the absence of oxygen ultimately determines their expression in the extracellular space in hypoxia. In parallel, we explored the cellular and physiological roles of a relatively uncharacterized oxygen sensing enzyme, ADO. ADO synthesizes hypotaurine and directly regulates protein stability through catalyzing a post translational modification in an oxygen dependent manner. Here we show that ADO is essential for the growth and survival of cancer cells and promotes tumor xenograft growth. ADO mitigates reactive oxygen species (ROS) through regulating proline metabolism. These data provide novel insights into how depletion of an oxygen dependent enzyme may elicit a metabolic imbalance leading to loss of redox homeostasis. Taken together, this thesis explores the role and the importance of oxygen and oxygen dependent enzymes that drive acute responses such as affecting the disulfide bond formation of protein folding and deregulation of the cancer metabolome.

Keywords: ADO
Hypoxia
Oxygen Dependent Enzymes
PRODH
Protein Folding
Tumour Microenvironment
Advisor: Koritzinsky, Marianne
Essays in Financial and Theoretical Economics

In Chapter 1, we analyse a model in which a biased Institutional Investor may offer a share price to acquire voting rights over a corporate motion. The selling and voting decisions of each initial shareholder (with imperfect, private information about the firm’s value of the motion) depend on the private information held, but the selling decision also depends on the Institutional Investor’s price offer. The voting decision of the Institutional Investor depends on the bias and updated beliefs about the motion value (which depend on the quantity of acquired shares). We find that (i) if the magnitude of the bias is large enough, then, relative to the absence of the Institutional Investor, shareholder welfare increases (decreases) if the bias is against (for) the motion and (ii) the Institutional Investor is less willing to exert control as the quality of the private information increases. In Chapter 2, we use the ex-vote date of shareholder meetings to measure the value of corporate shareholder voting rights. We find that the value of voting rights is affected by the quantity and type of shareholder proposed motions and that the interaction between shareholder and management proposed motions negatively affects the value of voting. Our results suggest that the mean value of voting rights is about 1.01% of firm value. The measured drop in the ex-ante expected share price on the ex-vote date is analogous to the drop in share value after a price offer in the modelin Chapter 1. In Chapter 3, we analyse an intertemporal model of network formation. Individuals possess a quality variable whose evolution depends on the number and quality of the individual’s links. We introduce a definition of positive assortative networks and provide conditions for which our model of network formation supports positive assortative networks.

Advisor: Mondria, Jordi
Resilience and the Relationship between Care Environment and HIV Risk Factors in Orphaned and Separated Children and Adolescents in Western Kenya

Millions of orphaned and separated adolescents and youths (OSAY) in sub-Saharan Africa are at a disproportionately higher risk of many adverse health outcomes, including HIV and associated risk factors, as compared to their non-orphaned peers. This increased vulnerability may be due more to a combination of environmental, social, and psychological factors than orphan-status alone. Care environment has been linked to differences in physical and mental health as well as risk behaviours in this population; however, the mechanisms underlying these relationships are not well understood. This dissertation used rich data on the health and well-being of OSAY in Charitable Children’s Institutions (CCI, i.e. orphanages and rescue centers) and family-based care settings (FBS) to investigate the relationships between care environment, psychological resilience, resilience-building factors, and HIV risk factors in OSAY in western Kenya. The first study examined the psychometric properties of the 14-item Resilience Scale (RS14) tool for measuring psychological resilience in this population. It found a high level of internal consistency reliability, moderate convergent validity, and satisfactory construct validity; supporting the use of the RS14 in OSAY in western Kenya. The second study explored the relationships between care environment, social-psychological factors thought to promote psychological resilience, and psychological resilience. Individuals in CCIs showed greater resilience than those in FBS. Family support, social support, peer support, and volunteering were identified as factors that may facilitate the development of psychological resilience in this population. The third study investigated the causal mechanisms behind the relationships between care environment and HIV risk factors; examining these relationships longitudinally and decomposing the impact of care environment on HIV risk factors into the effects due to mediation, interaction, neither, or both. It found that CCIs provided a strong protective effect against sexual HIV risk factors and that none of resilience, peer support, family support, social support, volunteering, or having one’s material needs met were strong mediators of these effects. Together, these studies make an important contribution to the epidemiological literature on resilience and HIV risk in vulnerable populations in low resource settings, and provide insights to guide future research and support evidence-based policy interventions.

Keywords: HIV
Kenya
Orphans
Resilience
Risk
Social Support
Advisor: Braitstein, Paula
Shannon, Harry
Quantitative Education Researchers’ Conceptualization of Validity in Research Design, and Perceptions of their Work

The question of whether a study’s findings or conclusions are valid is a universal concern to all researchers, regardless of whether their approach to research is qualitative, quantitative or mixed. The various research traditions adopt differing philosophies about the nature of knowledge and reality. The literature in the quantitative research tradition has already made attempts to include qualitative and mixed methods in the same validity framework. Quantitative researchers usually use some version of the Campbellian validity typology to discuss research validity. Despite this validity typology originating in the fields of experimental and quasi-experimental causal studies, the internal-external validity framework is widely used in many fields including in education. However, differences in conceptualizations and disagreements abound in the use of the terminology associated with that framework. This exploratory study investigates nine quantitative researchers’ conceptualization of validity, their research practices, their research aims, and their decision-making process during research design and implementation. The participants’ contributions suggest that researchers do not limit themselves to one type of study despite using a particular validity framework. Results also indicate that researchers value flexibility in both their validity framework and their research protocols. Participants highlighted that rewards structures in the research community may not always promote good science. These insights are instrumental for understanding the barriers to having a common validity framework, and some of the prevalent issues related to when it comes to current practices of researchers.

Keywords: Education Research
Measurement Validity
Quantitative research
Research methodology
Validity in research design
Validity of inferences
Advisor: McDougall, Douglas
Predictors of Self-Injurious Thoughts and Behaviours Among Canadian Post-Secondary Students

Self-injurious thoughts and behaviours (SITB) represent a collection of life-threatening outcomes ranging from non-suicidal self-injury (NSSI, e.g., self-cutting) to suicidal thoughts (ST) and suicide attempts (SA). Suicide has been identified as a major public health problem and the second leading cause of death among young adults (18 to 24 years), with peak developmental transitions such as attending post-secondary education presenting as a strong catalyst for SITB engagement. Although SITBs have undergone rigorous examination over the years, there remain inconsistencies in the classification of non-suicidal and suicidal SITBs and the prevalence of subsequent risk factors specific to young adults. The purpose of this study was to examine the pre-existing and emerging biopsychosocial risk factors associated with suicidal thoughts and behaviours and non-suicidal self-injury among post-secondary students. While several researchers approach the topic of suicidal thoughts and behaviours separately from non-suicidal self-injury, this study examines the two constructs concurrently and explores risk factors common to both. Using data from the 2013 (n=354) and 2016 (n=270) American College Health Association–National College Health Assessment (ACHA-NCHA), a cross-sectional survey of the health behaviours of Canadian post-secondary students, this study examined the prevalence of 13 biopsychosocial risk factors in a group of students who endorsed engagement in SITB. Of the 13 risk factors examined in the current study, results demonstrate three pre-existing risk factors (interpersonal trauma, substance use and diagnosis of a mental health issue) and three emerging risk factors (disability identification, sleep disturbance and negative affect) converging in the two student samples. Understanding emerging risk factors may help improve suicide risk assessment tools and mitigate suicidal tendencies by providing clinical interventions at earlier stages for post-secondary students. Sleep problems may be a particularly important intervention target because of their non-stigmatizing nature and amenability to mental health treatment.

Keywords: post-secondary
risk factors
self-injurious behaviour
self-injurious thoughts
suicide
Advisor: Stermac, Lana
Unconsummated/Queer Loneliness

This dissertation is organized around a concept called queer loneliness, which I define as a state of unrequited longing, one that contests the borders between the presence and absence of sex. Whereas most queer theory has understandably worked to repair and refigure non-monogamy, this project approaches queer intimacy from the opposite direction, illuminating relations that often occur without sex, without contact, or without a human intermediary. Following from theoretical work on celibacy, autoeroticism, and asexuality, this project examines the criteria through which erotic behaviours become recognizable as sex, rather than as foreplay, fetishism, or masturbation. In this sense, loneliness is not only a paradigm that questions the collapse of sexual evidence and legitimized partnership, but also one that poses consequences for the legibility of erotic life in moving image media. Distance, seclusion, vicariousness, illegibility, and frigidity are all operative figures in this project, and I suggest that these aesthetic paradigms contest an insistence – whether in acts of seeing or interpreting – on union between beholder and object.My methodology combines engagement with queer thinkers, close formal analysis, and attention to sexual historiographies, thereby negotiating culturally specific modes of sexual epistemology through the peripatetic surprise of aesthetic reading. The project is periodized alongside increasing sexual privatization throughout the late 20th century in a variety of national contexts (Belgium, Czechoslovakia, Great Britain, Japan, Taiwan, the United States), focusing particularly on the sacralisation of nuclear family dynamics that proliferated globally during these decades. In this project, I excavate an alternative history of queer cinematic expression in the late 20th century, one that examines how this era simultaneously fortified a conservative, heteronormative pastoralism and permitted a set of stranger erotic relations to seclusion, atomization, and home spaces to take root. Ultimately, this project suggests that unconsummated, celibate, or non-companionate relationalities are not simply a form of negation, but an aesthetic mode, a form of ambient togetherness, a way of doing history, and a component of cinematic grammar.

Keywords: 1980s
1990s
asexuality
loneliness
media aesthetics
queer theory
Advisor: Cahill, James L.
Co-creating and Implementing a Community-Based Peer-Assisted Physical Activity Program to Promote Exercise and Sport Participation after Moderate-to-Severe Traumatic Brain Injury

Traumatic brain injury (TBI) is a leading cause of death and disability around the world, and moderate-to-severe TBI may result in long-term or lifelong sequelae that prevent individuals from returning to a pre-injury way of functioning. Physical activity (PA; e.g., exercise and sport) demonstrates the potential to alleviate some of this burden through meaningful health-improving activities that are positive for mood, community participation, and quality of life after moderate-to-severe TBI. However, adults with moderate-to-severe TBI do not participate in recommended amounts of PA. Therefore, establishing best-practice methods to support PA participation in the community after moderate-to-severe TBI is warranted for the purpose of improving long-term outcomes. This doctoral dissertation addresses that gap with (1) a scoping review of the current literature about community-based PA interventions after moderate-to-severe TBI, (2) an exploratory case study of an existing peer-based PA program being piloted in a YMCA fitness centre, (3) an interpretive case study of co-creating a tailored peer-based PA program with key stakeholders, and (4) an interpretative phenomenological analysis of COVID-19’s impact on program participants and their PA. Results showed (1) community-based PA interventions can lead to significant improvements in health-related outcomes after moderate-to-severe TBI, but further research is needed with sex and gender considerations, telehealth applications, and better intervention reporting; (2) the inner mechanisms of a peer-based PA program from the perspective of multiple stakeholders and the autonomy-supportive approaches needed to tailor the intervention for future users; (3) how the participation in and co-creation of a new optimized community-based peer-assisted program can increase PA autonomy, reduce PA barriers, and lead to important biopsychosocial benefits; and (4) the profound impact of COVID-19 and necessary considerations to support PA in a pandemic after moderate-to-severe TBI. Findings of this dissertation include implications for the rehabilitation sciences and literature. Integrated knowledge transfer approaches to co-creating a peer-based PA program in the community can lead to the co-production of knowledge between researchers and users, who benefit from health promotion opportunities that further their participation in society. Peer-based PA programs can transcend rehabilitation to the community context with positive health behaviours that extend beyond a formal intervention.

Keywords: Community
Exercise
Peer
Physical Activty
Sport
Traumatic Brain Injury
Advisor: Colantonio, Angela
Swaine, Bonnie