UVicSpace | Institutional Repository

 

UVicSpace is the University of Victoria’s open access scholarship and learning repository. It preserves and provides access to the digital scholarly works of UVic faculty, students, staff, and partners. Items in UVicSpace are organized into collections, each belonging to a community.

For more information about depositing items, see the Submission Guidelines.

 

Recent Submissions

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TEST Research security and open scholarship in Canada
(Open Scholarship Policy Observatory, 2023-11-17) Winter, Caroline
Research security—the ability to identify risks to research processes and outputs and take measures to mitigate them—is a longstanding concern for the research community and its stakeholders, from individuals to national governments. Although openness and collaboration are essential for advancing research, greater openness can also lead to greater risks. Securing digital data, knowledge, and other intangible outputs is especially challenging. This was made evident during the COVID-19 pandemic, when the pivot to virtual work environments and unprecedented levels of global collaboration and research sharing was accompanied by increased security threats.
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QPLEX: Towards the Integration of Platform Agnostic Quantum Computation into Combinatorial Optimization Software
(2024) Giraldo Botello, Juan Fernando; Müller, Hausi A.; Villegas Machado, Norha Milena
Quantum computing has the potential to surpass the capabilities of current classical computers when solving complex problems. Combinatorial optimization has emerged as a pivotal target area for quantum computers, as problems in this field are renowned for their complexity and resource-intensive nature. Moreover, these challenges play a critical role in various industrial sectors, including logistics, manufacturing, and finance. This thesis explores the integration of quantum computation into classical software tools as a means to potentially address combinatorial optimization problems more efficiently and effectively. This work introduces QPLEX, a Python software library that enables practitioners and researchers to implement the general mathematical formulation of a given combinatorial optimization problem once and execute it seamlessly on multiple quantum devices using various quantum algorithms. This software solution automatically adapts a general optimization model to the specific instructions utilized by the target quantum device’s SDK. It offers a versatile execution workflow capable of running gate-based hybrid quantum-classical algorithms for combinatorial optimization in a platform-agnostic manner. This approach reduces the programming overhead required for modeling and experimenting with combinatorial optimization solutions. Within this manuscript, we address and introduce the various aspects associated with the development of QPLEX in a clear and comprehensive manner. These aspects encompass the quantum algorithms and quantum hardware available in the library, along with QPLEX’s system design and implementation. Additionally, we provide a guide on how to use the library and conduct a thorough evaluation of the software solution within a specific use case as part of this thesis.
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Mechanisms of cerebral artery compliance at sea-level and following acclimatization to high altitude.
(2024) Underwood, Destiny; Smith, Kurt
Brain health is dependent on adequate cerebral blood flow (CBF) delivered through healthy compliant vessels that buffer pulsatile hemodynamic stress. Pharmacological interventions at sea-level (SL) and high altitude (HA, 5050m) that increase and lower CBF provide a useful experimental design to assess the mechanisms involved in buffering cerebrovascular hemodynamic stress. We characterized pulsatile hemodynamic damping factors (DFi), as an index of cerebral hemodynamic stress. DFi was calculated from pulsitility (PI) in the internal carotid (ICA) and middle cerebral arteries (MCA) at SL and HA following pharmacological attempts to increase (SL=Dobutamine, DOB; HA = DOB+Actetazolamide, DOB+ACZ) and decrease (Indomethacin; INDO) CBF in healthy lowlander adults (n=12, 4 females). Cerebrovascular hemodynamics in the ICA (flow [QICA], PIICA) and MCA (velocity [MCAv], PIMCA) were measured using ultrasound; DFi=PIICA:PIMCA. Administration of DOB (2-5μg/kg/min) at SL, DOB+ACZ (5μg/kg/min+10 mg/kg) at HA, and INDO (1.45 mg/kg) at SL and HA were performed on separate days in randomized order. No QICA response were observed following DOB, while QICA increased following DOB+ACZ (change+41±24 ml.min-1, p=0.01), and decreased following INDO at SL (change-53± 56 ml.min-1,p=0.04) and HA (change -41± 18 ml.min-1, p=0.004). DOB and DOB+ACZ administration differentially altered HR (change-3 bpm; change+5 bpm, p=0.02), ICAV (change-6 ± 10 cm.s-1; change+10 ± 11 cm.s-1; p=0.04), MCAv (change+0 ± 10 cm.s-1; change+17± 5 cm.s-1), and PIICA (change+0.4 ± 0.2 a.u; change +0.2 ± 0.09 a.u.; p=0.03). DOB reduced DFi (change -0.1± 0.05, p=0.02) at SL. Meanwhile DFi following INDO was significantly lower at HA (change -0.54± 0.3a.u, p=0.02) but not at SL (change -0.26± 0.3 a.u, p=0.18). The results from these two field experiments highlights that reducing CBF via cyclooxygenase inhibition detrimental alters the buffering of cerebrovascular hemodynamic forces. In contrast, at HA when CBF is increased following DOB+ACZ cerebrovascular hemodynamic regulation was preserved.
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An Intersectionality-Informed Analysis of Loneliness and Discrimination Experienced by 2S/GBTQ+ People Living With Disabilities Before and During the COVID-19 Pandemic
(2024) Amato, Anthony Theodore; Lachowsky, Nathan; Card, Kiffer
Introduction: Social inequities such as loneliness and discrimination due to sexual orientation (herein, discrimination) are prevalent across disabled people and Two-Spirit, Gay, Bisexual and Trans men, Queer and Non-Binary (2S/GBTQ+) communities. However, little is known about how loneliness and discrimination were experienced in Canada at the intersection of disability and 2S/GBTQ+ communities, especially before and during the COVID-19 pandemic. Method: To address this knowledge gap, four cycles (2019, 2020, 2021, 2022) of cross-sectional, bilingual, community-based Sex Now survey data were used, which included 2S/GBTQ+ people aged 15 years or older and living in Canada. A total of 12,355 2S/GBTQ+ participants responded to loneliness outcomes, and 11,575 to discrimination outcomes. A multi-stage data analysis was conducted. First, crosstabulations and chi-square tests were used to describe and test for differences across outcomes across the four survey cycles. Second, pooled data were analyzed to describe and test for differences in outcomes based on social determinants of health. Third, stratified analyses were repeated for participants living with and without a disability. Finally, only among 2S/GBTQ+ participants living with disabilities, multivariable logistic regression models of each outcome identified 1) temporal trends by survey year, and 2) social determinants of health correlates. Results: There were statistically significant differences in outcomes across survey cycles, which were greater among 2S/GBTQ+ participants living with a disability. Compared with 2019 (before COVID-19), the odds of reporting loneliness were greater for 2S/GBTQ+ participants living with disabilities in 2020 and 2021 (but not 2022). 2S/GBTQ+ participants living with a disability who reported a racialized identity, financial strain, or a gender-expansive identity had greater odds of reporting loneliness. Compared with 2019 (before COVID-19), decreased odds of reporting discrimination were found in 2021 and 2022 (but not 2020). Generally, older 2S/GBTQ+ participants living with a disability were less likely to experience discrimination. 2S/GBTQ+ participants living with disabilities who were racialized, queer versus bisexual identified, and gender-expansive reported greater odds of discrimination. Conclusions: These findings suggest that 2S/GBTQ+ people living with disabilities were impacted by greater loneliness and lesser discrimination during COVID-19. However, social inequities were also present among 2S/GBTQ+ people living with disabilities. Equitable policy planning is needed to ensure that underserved yet deserving communities are not disproportionally affected by future pandemics and associated public health responses.
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Paleoenvironmental interpretations of the Late Triassic marine realm across the Canadian Cordillera: Slow burn of the end-Triassic mass extinction
(2024) Lei, Jerry; Husson, Jon
Despite representing some of the most pivotal intervals in evolutionary history, the timing and tempo of mass extinction events have remained contentious. Many studies have contributed evidence suggesting that ecosystem disturbance associated with the end-Triassic mass extinction (ETME) began prior to the Triassic/Jurassic boundary (TJB), but the extent and duration of this leadup phase is not well established. This uncertainty is exacerbated by a comparative lack of studies investigating the ETME within the context of long-term Late Triassic trends, as well as by the dominance of Tethyan datasets in paleoenvironmental interpretations of the epoch. The research presented in this dissertation consists of a multi-faceted investigation of Panthalassan paleoenvironmental conditions spanning from the Norian/Rhaetian boundary (NRB) to across the TJB, as recorded in western Canadian marine strata. An instance of coral reef collapse on Mount Sinwa, British Columbia, is associated with the paleoenvironmental disturbance around the NRB via conodont and Re–Os isochron age constraints. Ratios of 87Sr/86Sr are observed to gradually increase across the late Norian, as opposed to the sudden drop previously observed in Tethyan datasets, indicating the NRB disturbance was not triggered by mantle-derived volcanism on a global scale. A 3 – 4‰ negative excursion in δ13C values is captured in the latest Norian on Mount Sinwa, consistent with the global carbon cycling disruption proposed to occur around the NRB by prior studies. The conodont species Mockina carinata and Mockina englandi are especially abundant in the Norian and Rhaetian strata of Panthalassa. Morphometric analyses on these two conodont species demonstrate a gradual reduction of platform width across the NRB. These intraspecific trends are likely a more conservative parallel to concurrent intergeneric morphology shifts observed in Tethyan conodonts, together potentially implying a global shift in conodont diet away from mineralized food sources during this time. This may suggest that the biomineralization pressure typically associated with the ETME began at a lesser severity around the NRB, and that conodont biodiversity underwent only limited recovery between the substantive turnover at the NRB and complete extinction of the class around the ETME. Specimens of both these species that have a mid-platform length to breadth ratio greater than 3:1 are observed exclusively in the Rhaetian, a clear sign of morphotype origination or subspeciation, with implications for improved biostratigraphic utility. The compilation of δ13C values across stratigraphic sections from Williston Lake, Holberg Inlet, and Kyuquot Sound in the Canadian Cordillera develops a comprehensive Panthalassan record spanning from the Norian through into the Hettangian, with representation from a variety of depositional settings across a wide paleogeographic area. Three distinct negative excursions are observed, with one proximal to the NRB, one within the Rhaetian, and another across the TJB. The somewhat variable positions of these excursions suggest that the earliest “precursor” excursion associated with the Rhaetian leadup to the ETME may be indistinguishable from an excursion associated with the NRB. Some of the observed excursions are too large in magnitude to reflect shifts in global ocean water chemistry, necessitating a local-scale amplification mechanism, such as disturbance-triggered organic carbon respiration in a water column with restricted circulation. Nevertheless, this evidence for repeated carbon cycling instability indicates the ecological distress that initiated around the NRB persisted across the Rhaetian, escalating into the TJB. Drawing from a combination of lithological, paleontological, and geochemical evidence from across the Canadian Cordillera, this dissertation supports the hypothesis of a protracted ETME that initiated as early as the NRB. With implications of elevated extinction pressure persisting for millions of years before the climax at the TJB, this research challenges preconceptions of the timescale in which mass extinction events ought to be envisioned.