Electronic Theses and Dissertations (ETD)

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All theses from 2011 to the present are in this collection, as well as some from 2010 and earlier years.

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A microgel-based approach for optimized wound healing
(2025) Moretti de Andrade, Thiago Antonio; Akbari, Mohsen
Skin tissue engineering strategies that leverage the properties of biomaterials for in vitro wound healing investigation have emerged as an effective approach to creating more realistic models providing ethically and scientifically preferable models to animal experimentation. Granular material with spherical-shape and rod-shape have stood out in this scenario, creating a biocompatible interface for cell proliferation and migration. Gelatin Methacryloyl (GelMA) is a pivotal crosslinkable hydrogel in the fabrication of granular biomaterials due to its versatile properties in enhancing the mechanical strength, and biocompatibility. Therefore, the combination of GelMA’s cell-friendly properties and the enhanced porosity generated among its particles in microgel mimicking the extracellular matrix underscores the novelty of this study in the investigation of the keratinocytes’ viability and migration in GelMA microgel-based to optimize the wound healing process in a more effective and realistic method than the regular 2D methods. To address this investigation, it was strategically designed and printed (by Anycubic 4K Mono printer - DLP-based) one structure to be used as a mold of the 7.5% GelMA with keratinocytes (1.0 × 106 / mL of GelMA) in the 12-well plates after its crosslinking by 405 nm LEDs. The middle of this mold was designed to form one vat in the middle of the 7.5% GelMA that is intended to be placed the microgel (10% GelMA spherical-shape with 2.5% GelMA between the particles to crosslink all microgel in the 7.5% GelMA ring) with no keratinocytes. As the microgel was surrounded by keratinocytes in 7.5% GelMA (from its bottom and around), it was possible to investigate the viability and migration of the keratinocytes from the GelMA to the microgel layer naturally and by themselves, with neither stimulation nor chemotaxis. The control group was the 10% GelMA bulk (non-microgel, no droplets) placed in the vat, in the same conditions as the experimental group (10% GelMA spherical-shape droplets). Live/dead was performed to qualitatively evaluate the keratinocytes’ viability and migration; DAPI stain analyses (from the 3D construct samples and from the 2D cryostat-slices’ samples) were performed to qualitatively confirm keratinocytes’ migration. All analysis were investigated on days 1, 3 and 7. Overall, the model has been shown to be feasible, more realistic and promising for studying cell migration, taking advantage the own GelMA’s porosity and the additional GelMA microgel’s porosity, making suitable for short-term in vitro wound healing investigation with no vascularization. The model established here was more effective and realistic to investigate keratinocyte migration from the bottom and across surrounding the microgel area, providing a more relevant system than traditional 2D cultures, such as scratch assays or Transwells. With the second mold design, the most suitable method has been established, and the optimal GelMA bioink concentration (2.5% of GelMA bioink) for promoting keratinocyte migration has been identified. Beyond this, the established method offers a foundation for future studies and broader applications in wound healing and regenerative medicine, for example, investigating the potential effects of the microgel in the wound healing in vitro and in vivo, associated or not with pathologies, such as diabetes, that can impair the wound healing process.
Synthesis of functionalized water-soluble sulfo-pillar[6]arene analogs for binding pharmaceuticals
(2025) Wilson, Chelsea R.; Hof, Fraser Alan
Functionalized water-soluble macrocyclic hosts are increasingly realizing their potential for use in biological applications. Almost all such efforts require synthetic modification of the parent macrocycle. Through the synthetic manipulation of a host, one can tune the non-covalent interactions, driving complexation towards stronger and more selective binding, as well as introduce new functional elements. This dissertation focuses on developing new functionalization strategies for the high-affinity host sulfo-pillar[6]arene, which has growing potential in the field of supramolecular therapeutics. At the start of this thesis there were no reports of methods to modify this host, limiting its potential. This work presents synthetic approaches that provide multiple new functionalized sulfo-pillar[6]arene analogs that vary the scaffold’s surface area, anionic charge, and fluorescence properties. This works starts with a new synthetic protocol for synthesis of ethoxypillar[6]arene, a key synthetic intermediate for water-soluble sulfo-pillar[6]arenes. Access to this material had been limited to small quantities requiring laborious purifications. The new protocol is chromatography-free and provides large (20 – 40 g) quantities of pure ethoxypillar[6]arene in a day’s work. From this point, multi-step synthetic routes allowing for modifications to multiple regions of the macrocyclic scaffold were developed. The first scaffold modification explored was extending the binding cavity with one and two phenyl groups. This led to the development of novel extended sulfo-pillar[6]arene analogs with increased host-guest contacts. The ability of the new hosts to bind direct oral anticoagulants (DOACs) was established, and the structure-function relationships of the closely related hosts and a subset of these drugs were determined. As one example, the addition of an extended binding arm with preservation of the same overall amount of charge resulted in a 6-fold increase in affinity (Kd = 230 nM) towards the pharmaceutical agent betrixaban. Attempts at incorporating additional extending arms identified instability of the more highly substituted scaffold, highlighting the synthetic challenges of this kind of work. This modification route also introduces a new fluorescent functionality to the host, opening the door to new supramolecular sensing applications for sulfo-pillar[6]arenes. The second modification type was controlling the cavity charge. A multi-step synthetic pathway was developed, allowing for precise control over the number (−12, −8 or −6) and spatial distribution of charges. To do this, a regioselective oxidation provided synthetic access to two or three aromatic rings in the macrocyclic scaffold. Through a hydrodeoxygenation step these rings were defunctionalized. This led to the establishment of a new class of water-soluble host with variable charge, pseudo sulfo-pillar[6]arenes. Preliminary binding data with the guest DAPI demonstrated that altering the charge has a significant effect on binding, with two (−6) regioisomers exhibiting a ~30-fold difference in affinity, and a −6 analog having equivalent potency to a −12 species. This work shows how seemingly subtle structural changes can lead to large impacts on host properties. Overall, this dissertation presents new synthetic methods in altering the chemical composition of sulfo-pillar[6]arenes, generating five new water-soluble synthetic hosts. It explores the new hosts high-affinity binding and selectivity for a variety of pharmaceutical agents and the dye DAPI. The creation of new synthetic compounds and functionalization strategies will help in developing better supramolecular therapeutics.
Investigating the pro-viral activity of Staphylococcus aureus lipases on influenza A virus infections
(2025) Witt, Rachel; Goncheva, Mariya
Influenza A virus (IAV) is the causative agent of the seasonal flu and of severe influenza pandemics in humans. A serious complication of IAV infections is secondary bacterial infection, which can result in bacterial pneumonia and increased mortality. Staphylococcus aureus is the 2nd most common bacterium found in co-infection with IAV, and has been shown to enhance viral infectivity. Lipase 1 is an enzyme secreted by S. aureus, and treatment with it during infection increases the proportion of infectious IAV particles by up to 10-fold in primary fibroblast cells. While the mechanism of this effect is currently unknown, we hypothesise that Staphylococcus aureus lipases modulate select host lipids involved in the budding of influenza A virus virions, resulting in enhanced viral infectivity. Our focus in these experiments is to better understand how this pro-viral effect is being conveyed, and what modifications the lipases are making during an infection. We worked with infections in primary fibroblast cells, and first determined that both S. aureus lipase 1 and lipase 2 are capable of producing the pro-viral effect, and that the effects of the two lipases are not additive. Next, we assessed whether a single exposure to lipase resulted in sustained pro-viral activity in subsequent infections, and found that the lipases do not provide an inheritable benefit to future virions. To look more closely at the molecular changes involved, we used untargeted lipidomics to look for modifications in the host Chicken Embryo Fibroblast (CEF) cell lipidome when exposed to S. aureus lipases during an IAV infection. Through this we identified 20 lipids that were significantly modulated in the lipase-treated samples. The results of the lipidomics were used to inform lipid-treatment infections, where exogenous lipids were added to infections without the presence of lipase. There, we found that treatment with phosphatidylinositol may provide a pro-viral effect similar to the lipases. Together, these experiments give new insight into the mechanisms of the pro-viral activity of S. aureus lipases during co-infection, and could help drive future IAV research and treatments.
Healing through connection: Creating space for relationality in mental health and criminal justice
(2025) Dwornik, Ania; White, Jennifer; Corntassel, Jeff
The Canadian criminal justice system is simultaneously experiencing an overrepresentation of Indigenous peoples and persons with mental unwellness. Both challenges have generated significant study and attention, yet there has been little exploration of the relationship between them. Rather, consistent with Western traditions of knowledge production, these issues have been studied in isolation from one another, with Eurocentric theories of health and justice used to explain and resolve them. This includes the biomedical model of mental illness, which individualizes experiences of emotional distress and fails to recognize the impact of colonial trauma. Such trends perpetuate colonization and fail to deliver solutions that are embedded within Indigenous ontologies, epistemologies, and cosmologies. Consequently, they may not meet the needs of Indigenous people. Through three distinct but inter-related academic papers I open a series of ethical spaces (Ermine, 2007) to explore these topics. In the first paper I explore the relationship between Indigenous health theories and Mad Studies. In the second I describe a qualitative study that explores the perspectives of six Indigenous persons with criminal justice system (CJS) involvement. In the third, I explore the potential for using restorative justice to help decrease the over-representation of Indigenous peoples with mental unwellness in the CJS. I acknowledge important concerns about cooptation, appropriation and knowledge extraction and align with critical scholarship including Mad Studies and Indigenous works on historical trauma. Through qualitative research I listen to the voices of six Indigenous participants who identify relationality as a key feature of this work and suggest that service providers hold unique potential for helping to decolonize and decriminalize mental unwellness. I propose two ways this can be applied through direct practice: inter-relational practice and restorative justice (RJ). By using this practice and framework, service providers can directly participate in the decriminalization and decarceration of Indigenous peoples with mental unwellness in Canada.
Navigating the social seas: Using fuzzy cognitive mapping to understand community impacts at the intersection of offshore wind energy, fisheries, and climate change in the Gulf of Maine
(2025) Batchelder, Eliza; McClenachan, Loren
Globally, as oceans warm and the rate of fishing continues to increase, the health of marine ecosystems has declined. From a community perspective, warming ocean temperatures have led to fish stocks shifting into regions that are harder to access or no longer viable for fishing, increased storm occurrence has destroyed important port infrastructure, and the adaptive capacity of fishing communities is sometimes limited. Around the globe, governments and energy developers have identified offshore wind energy generation as a viable and critical technology to aid in the transition away from fossil fuels to mitigate future climate change impacts. However, the nature of large-scale energy development projects means that the magnitude and directionality of benefits and impacts are not always well-understood at the community scale, and efforts to identify paths for coexistence among fisheries and offshore wind have been met with resistance from the fishing industry. This study aims to assess what stressors and opportunities are the most impactful to a fair future for commercial fisheries in the Gulf of Maine, where these various challenges converge. I use mental models and fuzzy cognitive mapping (FCM) to assess how commercial fishers and fisheries decision makers perceive the impacts from offshore wind development, climate change, and other regional stressors, and where there are areas of common prioritization. I followed the multi-step approach to cognitive mapping developed by Özesmi and Özesmi (2004) to collect and analyze mental model data. Both groups had complex understandings of what would contribute to or threaten a fair future for commercial fisheries in the Gulf of Maine. In addition to the development of new energy infrastructure in proximity to fishing grounds, respondents from both stakeholder groups indicated that fishing communities in the Gulf of Maine face a variety of changes, such as warming waters and shifting species distributions, rising costs of living, and changing gear regulations due to North Atlantic Right Whale conservation measures. These concepts frequently interact with one another in ways that reinforce or change the impact of one concept on the overall system. My results showed many similarities among stakeholder groups. Both commercial fishers and fisheries decision makers viewed access to healthy fish stocks as important for a fair future for fisheries and shared common values about the importance of preserving working waterfronts and job opportunities. Despite these commonalities, the two groups had different perceptions of what would be the primary drivers of negative or positive change. Fisheries decision makers viewed climate change, offshore wind, and stock health as equally impacting future access to fish stocks, whereas commercial fishers viewed offshore wind as the primary threat to accessing fish stocks. Although each group had unique views on the importance of climate change within the overall system, there was a common understanding that renewable energy would help address climate change and the impacts that it had on surrounding ecosystems and communities. However, fisheries decision makers were more likely than commercial fishers to view offshore wind as contributing positively to climate change, suggesting that decision makers’ and fishers' underlying definitions of sustainability were not always aligned in scale. Fisheries decision makers took a higher-level approach to achieving “sustainability” through large-scale energy development and achieving federal, if not global, climate targets, whereas fishers took an individual and community-level approach to defining what sustainability means. Additionally, fishers’ opposition to compensation packages as a means of addressing impacts from offshore wind development reinforces concerns about the distributional benefits of offshore wind projects. When considered together, my findings suggest that the regional vitality of coastal communities is being impacted by more than just offshore wind projects, and thus, proposals for financial support and equitable energy transitions should attempt to address underlying and system-wide challenges such as preserving working waterfronts, habitat restoration, affordable housing, or clean energy subsidies.
XE' XE' sacred indigenous spiritual connection in early childhood education and care
(2025) Alphonse, Danielle; Carere, Sandrina; Restoule, Jean-Paul
Western early childhood developmental milestones focus on young children’s physical, emotional, and social development, but there is a dearth of research addressing young children’s spiritual development, and even less about spiritual connection. In my work as an Indigenous researcher and early childhood educator, I have observed that spiritual connection is often missing or minimized in both curriculum and guidance in Indigenous early childhood programs. Therefore, this research explored how early childhood educators can enhance children’s spiritual connections in early childhood settings in Indigenous communities. Rather than seeking to intervene in a scholarly debate about spiritual connection for Indigenous children and communities, the project foregrounded community knowledge and Indigenous ways of knowing and being. The research was guided by an Elders’ advisory from my First Nation, Quw'utsun. The Elders advised early in the process that using the concept of spiritual development was not aligned to Quw'utsun worldview and suggested to change the wording to XE' XE' (sacred) spiritual connection. The Elders advisory recognized the importance of aligning in words with an Indigenous worldview, as spiritual connection is innate in us as Quw'utsun people. Drawing on visits and interviews with Quw'utsun Elders and educators, the research was guided by the following question: “How can early childhood settings enhance Indigenous children’s spiritual connection through curriculum and guidance in early learning environments?” Knowledge gathered in community emphasized how Elders and early childhood educators’ stories inform our Quw'utsun community in how to support spiritual connection with language revitalization, teachings, stories, and connection to the land. Insights shared by Elders and early childhood educators highlighted central themes from a Quw'utsun perspective, including the following: the family is acknowledged as the child’s first teacher; spirituality is woven through ancestral lines within each family; connection to spiritual ways is enacted in thoughts, prayers, practices, and teachings that are understood by the community; Quw'utsun worldview and spirituality are not separate from daily life but are understood as fundamental ways of being; and finally, traditional Indigenous knowledge is key to healing the Quw'utsun people based on ancestral teachings and stories shared by Elders. The research brings to light that historical and intergenerational trauma significantly impact the ability of families to uphold and transmit traditional spiritual teachings during the early years and that intergenerational transmission of spiritual knowledge within families is essential, with early childhood education programs serving a foundational role in supporting language resurgence and safeguarding spiritual connections to the land and ancestors. When the significance of land-based learning, language revitalization, cultural practices, and teachings are recognized, spiritual connection in the early years can be meaningfully supported and sustained for generations. Child development policies at both national and international levels encourage a pathway for Nations to initiate and develop themselves to support spiritual connection within early childhood education and curriculum development. Thus, while this study focused on the early years, it has implications for promoting positive spiritual connection for Indigenous learners across their educational journey.
Improving mental health service access for women survivors of child sexual abuse in BC, Canada. A system thinking perspective.
(2025) Hoff-Bell, Mackenzie; Lepore, Walter
This study explores the systemic barriers that women child sexual abuse survivors (WCSAS) face when accessing mental health services in British Columbia (BC), Canada. Using an interpretive, qualitative, and system thinking approach, this study integrates the perspectives of survivors and service providers to uncover economic, social, cultural, and structural barriers to care. Semi-structured interviews with WCSAS and a mental health service provider (MHSP) informed a thematic analysis and the creation of actor and causal system maps. The study identifies key intervention points to enhance accessibility and recommends trauma-informed, culturally responsive, and publicly funded psychotherapy services. It fills a critical gap in Canadian literature by centring survivor voices and offers actionable pathways for policy, programming, and system reform. This research advocates for equitable, long-term support for WCSAS across BC’s fragmented mental health system.
Evaluating vegetation as a dust storm mitigation tactic in the hydroelectric reservoir environment through drone surveying and GIS modelling
(2025) Voss, Gillian; Bone, Christopher
Dust storms are a growing problem in Canada as hydroelectric reservoirs, an increasing popular energy source, create environments that are highly vulnerable to such events due to the vast expanses of fine sediment that are exposed when reservoir levels are lowered. Mitigation tactics, most commonly the planting of vegetation, are being implemented at these sites to reduce dust erosion. However, the vastness of the reservoir beaches keeps project costs high and the fluctuating water levels limit the amount of time when seeding is possible. This thesis addresses these issues of high costs and a limited time frame by identifying ways in which that seeding can be optimized, both in rate and location, without sacrificing the quality of dust reduction. This study was conducted on Middle Creek North Beach on the eastern side of the Williston Reservoir in British Columbia and involved data collection via Unmanned Aerial Vehicle (UAV) and as well as in situ measurements. In Chapter 2, UAVs are evaluated as a tool for monitoring vegetation in the reservoir beach environment. This evaluation included a comparison of sensors (LiDAR and photogrammetric) and three flight parameters (altitude, speed, and side lap). In this environment and with the small-scale vegetation as the subject, the photogrammetric sensor significantly outperformed the LiDAR, and a lowered altitude was found to be the most impactful flight parameter on data quality. In Chapter 3, a series of regression models quantifying the relationship between dust, vegetation, and topographic variables are tested and compared. It was determined from this analysis that low seeding rate produces similar dust reduction to that of higher (and most costly seeding rates), and that the windward edge and the shoreline of the beach were especially vulnerable areas that should be prioritized for future mitigation. This thesis shows how modern technologies such as UAVS and GIS can be implemented into dust storm mitigation efforts. The methods developed in the thesis have the potential to be applied to hydroelectric settings facing similar challenges which will be crucial as this industry continues to grow.
A comparative policy review of undocumented children and their access to healthcare in Sweden and Canada
(2025) Akhigbe, Onome Daphne; Brunet-Jailly, Emmanuel
This study examines the policies governing access to healthcare for undocumented children in Sweden and Canada, with a focus on the implementation of these policies and the barriers to healthcare access in both countries. During this study, no specific comparative study was found that focuses on undocumented minor migrants in both Sweden and Canada. This gap in the existing literature presents a unique opportunity to explore the approaches of both countries to the issue of access to healthcare for undocumented children, as both countries are signatories to the Convention on the Rights of the Child. Furthermore, both countries have decentralized healthcare systems with varying responses to undocumented children and access to healthcare. The core research problem revolves around the gap between the rights to healthcare for undocumented children as ratified by both countries in 1989 at the United Nations’ Convention on the Rights of the Child (UNCRC) and the access they receive. Guided by research questions that explore (1) how international conventions are translated into domestic policy, (2) how immigration policies can override or shape healthcare access, (3) the key barriers undocumented children face in each country, and (4) how policy implementation differs, including ethical considerations, this study seeks to highlight the disconnect present between domestic and international legal and policy frameworks and lived experiences. The research began with a review of academic and grey literature in both Canada and Sweden to establish the context and identify key policy issues, followed by qualitative data collection through interviews with stakeholders such as healthcare professionals, researchers, authors who are knowledgeable on the issue, humanitarian workers, lawyers – see participant information in appendix (A) as well as a review of the relevant policy documents. By comparing the two countries, the review aims to identify some of the legal, social, ethical, and indirect barriers that hinder their access to healthcare. The study revealed that Sweden guarantees healthcare for all children, including undocumented minors, but faces implementation barriers due to limited provider awareness. Canada lacks a cohesive policy, with only Quebec offering similar access, resulting in inconsistent coverage that is largely dependent on provincial policies and humanitarian efforts. This research contributes to the understanding of the challenges that undocumented children face by identifying the gaps in the implementation of policy and practice and the need for a cohesive intersection between healthcare access and immigration policies. The study concludes with four policy recommendations aimed at aligning laws with human rights standards, protecting confidentiality, expanding family-centred care, and improving public awareness in both countries.
Temperature-controlled nanoaperture optical trapping
(2025) Letwin, Keiran; Gordon, Reuven
Nanoaperture optical trapping (NOT) enables the capture of single proteins to detect their conformational dynamics without labeling or tethering, thus preserving their structure. Protein folding is highly sensitive to environmental conditions, making the investigation of thermodynamic parameters a robust method for probing conformational stability. While previous studies have employed laser-induced heating to modulate the local temperature, such methods are limited in accessing broader temperature ranges. In this work, the low-temperature dynamics of individual Bovine Serum Albumin (BSA) are investigated using a custom-built temperature-controlled stage. The transitions between the normal (N) and fast (F) conformational states of BSA were uncovered. Notably, the N form exhibited a maximum occupancy at \(21 \pm 1\,^{\circ}\mathrm{C}\), which was interpreted as the point of maximal thermodynamic stability for the compact N state relative to the F state. This approach enabled the extraction of single-molecule thermodynamic parameters without requiring modification to the protein's native structure, providing a multifaceted NOT method for broad applications.
From coal to negative emissions: Modelling the decarbonisation of Alberta’s power grid
(2025) Lyseng, Benjamin Cal; Rowe, Andrew Michael; Wild, Peter Martin
This dissertation models the decarbonisation of Alberta’s power grid, transitioning from primarily coal-fired generation to delivering net-negative emissions. Three key stages of the transition are analysed using optimisation and simulation methods: the transition from coal to natural gas under carbon pricing, integration of 80% variable renewable energy (VRE) using power-to-gas (PtG) for long-duration energy storage, and the operational implications of direct air capture (DAC) for achieving negative emissions. In the first study, carbon pricing is found to accelerate emissions reductions, especially through coal-to-gas switching. The second study demonstrates that PtG can support an 80% VRE system by reducing VRE capacity and curtailment through long-duration energy storage. In the final study, DAC operation is shown to be closely tied to the marginal low-carbon generator. Overall, this work provides robust modelling and insights for regional decarbonisation strategies.
Enhancing cybersecurity text classification via AMR based augmentation and drift simulation with reinforcement learning
(2025) Ahmed, Hadeer; Traore, Issa
Natural language processing (NLP) is increasingly applied to cybersecurity text classification, but two challenges limit its effectiveness. First, access to high-quality labeled cybersecurity text is limited because organizations rarely share sensitive incident reports or vulnerability descriptions. Second, the rapid evolution of cyber threats leads to a decline in model accuracy as novel attack types and information emerge. Current text augmentation methods only make small surface-level edits and often fail to keep important domain-specific terminology intact. Existing drift handling techniques also fall short, as they rely on generic strategies that do not capture how cybersecurity text evolves over time. They also lack transparency, making them difficult to trust in security-sensitive domains. This dissertation introduces two frameworks to address these limitations. The first, AMR-CLONALG, combines Abstract Meaning Representation (AMR) graphs with a clonal selection algorithm to generate text samples that preserve semantic meaning while introducing controlled variation in syntax and vocabulary. This enables the expansion of small datasets without compromising accuracy. The second framework, Drift-RL, leverages reinforcement learning to simulate different patterns of data drift, including sudden, gradual, incremental, and recurring. This supports a systematic evaluation of the robustness of the model under changing data distributions and provides a benchmark for studying the effects of drift. Together, these frameworks strengthen cybersecurity text classification by improving performance in low-resource settings and enabling rigorous testing of resilience against changing data. Both emphasize transparency, ensuring that their outputs remain interpretable and accountable in security-critical applications.
Fair division of indivisible items
(2025) Hsu, Kuang-Yu; King, Valerie D.
We study the fair division of indivisible items. In the general model, the goal is to find a way to allocate m indivisible items to n agents, while satisfying some fairness criteria. We are particularly interested in the fairness criteria of maximin share (MMS), envy-freeness up to one item (EF1), and envy-freeness up to any item (EFX). Additionally, we study a recently-introduced graphical model that represents the fair division problem as a multigraph, in which vertices correspond to agents and edges correspond to items. The graphical model stipulates that an item can have non-zero marginal utility to an agent only if its corresponding edge is incident to the agent's corresponding vertex, capturing the idea of proximity between agents and items. It is desirable to allocate edges only to their endpoints. Such allocations are called orientations, as they correspond naturally to graph orientations. Our first contribution concerns MMS allocations of mixed manna (i.e. a mixture of goods and chores) in the general model. It is known that MMS allocations of goods exist when m <= n+5. We generalize this result by showing that when m <= n+5, MMS allocations of mixed manna exist as long as n <= 3, there is an agent whose MMS threshold is non-negative, or every item is a chore. Remarkably, our result leaves only the case in which every agent has a negative MMS threshold unanswered. Our second contribution concerns EFX orientations of multigraphs of goods. We show that deciding whether EFX orientations exist for multigraphs is NP-complete, even for symmetric bi-valued multigraphs. Complementary to this, we show symmetric bi-valued multigraphs that do not contain non-trivial odd multitrees have EFX orientations that can be found in polynomial time. Our third contribution concerns EF1 and EFX orientations of graphs and multigraphs of chores. We obtain polynomial-time algorithms for deciding whether such graphs have EF1 and EFX orientations, resolving a previous conjecture and showing a fundamental difference between goods and chores division. In addition, we show that the analogous problems for multigraphs are NP-hard.
Using historical analysis to inform the ecological applications of nautical charts
(2025) Dhillon, Ursula; McClenachan, Loren
As coastal ecosystems collapse, historical ecologists have taken interest in the long-term dynamics of kelp forests (Macrocystis pyrifera and Nereocystis luetkeana). Nautical charts created by colonial cartographers often include historical representations of kelp forest distribution and are useful for reconstructing the historical baselines of kelp ecosystems on the west coast of North America. To examine the limitations and possibilities of how these nautical charts can be applied to identify the historical presence of kelp forests, this thesis elucidates the historical context of these nautical charts, including the roles of key figures such as George Vancouver, George Richards, and George Davidson. This research also compares contemporary charts from the late-eighteenth century to the mid-twentieth century, demonstrating how the associated histories of nautical charts provide a more localized and holistic understanding of historical kelp and, more broadly, how historical research can inform the applications of historical sources to marine ecology.
Moisture response of CLT floor assemblies under indoor water leakage: Experimental and simulation-based assessment
(2025) Tariku, Bisrat H.; Mukhopadhyaya, Phalguni
As mass timber gains widespread use in sustainable construction, the long-term moisture performance of Cross-Laminated Timber (CLT) under damp service conditions remains a critical durability concern. This study investigates the moisture response of CLT floor assemblies under indoor water leakage through controlled laboratory testing and numerical simulations using WUFI 1D and 2D. Six assembly configurations were evaluated, including variations in surface exposure, joint conditions, and end-grain vulnerability. Results revealed that end-grain surfaces are highly susceptible to deep moisture ingress and prolonged retention, while inadequate joint sealing facilitates moisture infiltration through panel interfaces. Assemblies with cracked concrete toppings and no moisture barrier underneath showed deep moisture intrusion. Numerical simulations showed some similarity to the experimental drying trends, but significant deviations were observed; in particular, the 2D simulations exhibited even greater divergence due to multidirectional moisture transport and material property inputs required in two dimensions. This research highlights the importance of interface detailing, protective measures, and simulation-based assessment in enhancing the moisture durability of CLT assemblies in building’s service life.
A novel electrocatalytic Fe-TiO2 reactor for degrading persistent pollutants in wastewaters
(2025) Jahanshahi, Zahra; Herring, Rodney A.
The pervasive presence of persistent organic pollutants in water systems presents a major threat to the environment and public health. Being based on physicochemical properties of contaminants, conventional wastewater treatment techniques proved ineffective in eliminating these contaminants due to their widely variable and complex nature. With vast urbanization and limited water resources, the need for innovative and scalable solutions that can target these contaminants of emerging concern is crucial. This study presents the development and optimization of a novel Fe-doped TiO₂-based electrocatalytic reactor for the degradation of methyl orange, a representative organic pollutant. The degradation studies showed that the rate of methyl orange (MO) removal increases consistently with electric current, achieving up to 95.6% degradation at 16 A in 40 min without saturation, confirming steady hydroxyl radical generation. Using titanium electrodes, particularly when modified with a native TiO₂ layer, significantly improved degradation efficiency while reducing voltage requirements compared to stainless steel setups, achieving up to 94.7% degradation in 12 minutes at lower voltages. The efficiency of this process relative to electron density can be calculated as 22.4%, meaning generation of each hydroxyl radical consumes 4 to 5 electrons, which is orders of magnitudes more efficient than currently used methods, such as using chemicals and photonic activation. This work strives to address key limitations of current approaches in utilizing titanium dioxide crystals in treating water and wastewater, including catalyst immobilization, energy efficiency, and operational simplicity, paving the way for industrial applicability.
Characterizing morphological and elemental traits of threespine stickleback across an urbanization gradient on Vancouver Island
(2025) Mickens, Ashley; El-Sabaawi, Rana
Urbanization increasingly alters the landscapes surrounding cities. Anthropogenic impacts associated with urbanization, such as increased nutrients, habitat degradation, and the introduction of invasive species significantly impact the health of aquatic ecosystems. While many studies look at the relationship between urbanization and water quality, fewer look at how urbanization alters organismal traits, although there is increasing evidence that they are important for explaining the effect of urbanization on biodiversity. In this study, we examine the effect of urbanization on the traits of a common North American fish species, the Threespine Stickleback (Gasterosteus aculeatus). During summer 2022 and 2023, we collected stickleback from 15 freshwater locations on Vancouver Island across a gradient of urbanization. We quantified urbanization using three metrics constructed from several methods based on human population size density, infrastructure and land use. These metrics were used to analyze seven stickleback traits via principal component analyses (PCAs) and mixed effects linear models with AICc model selection. Our findings showed that urbanization increases body size, but had no relationship with the other six traits. This work provides recommendations on where to focus future sampling and conservation efforts while providing a framework for other researchers to carry out similar studies, thus increasing our understanding of the effects of urbanization on lake ecosystems.
Urchin distribution modelling and grazer control for kelp restoration
(2025) Rehill, Tessa; Baum, Julia Kathleen
Kelp, brown algae in the Order Laminariales, serve as important biogenic coastal habitat for a multitude of species. Losses of the highly productive kelp forest ecosystems these species form has been driven by climate change and the overpopulation of sea urchins, the dominant herbivore in kelp forests, leading to large swaths of kelp forests transitioning to urchin barrens from overgrazing. Yet, kelp forest restoration is hindered by the limited understanding of where urchin grazing pressures are highest and the extent to which urchin grazing prevents outplanted kelp from establishing. I address this gap first by developing predictive species distribution models (SDMs) through ensemble approaches that combine parametric and machine learning methods using long-term spatial datasets for three common urchin species in British Columbia (B.C.). Performance of these models, which identify environmental factors influencing urchin occurrence and abundance and generate novel spatial predictions of grazing intensity across B.C., varied with urchin response type and species. While occurrence models performed well at out of sample predictions (AUC = 0.84-0.91), abundance models showed lower predictive skill (R² = 0.42, F1 = 0.38-0.41). Regardless of species or model type, dissolved oxygen and temperature variables consistently emerged as the most influential environmental predictors. These SDMs effectively captured species-specific spatial patterns aligned with known ecological traits, helping to disentangle urchin spatial patterns and the abiotic factors shaping them. Next, I conducted an in-situ field experiment in Barkley Sound (B.C.), in collaboration with the Kelp Rescue Initiative, testing how urchin exclusion and green gravel outplanting performed across a gradient of urchin densities. I found that while physical exclusion reduced urchins within plots where kelp was outplanted, kelp survival and growth remained generally low, indicating potential limitations of exclusion design or weak kelp response under high herbivory pressures. Larger gravel substrates improved kelp survival but did not affect growth. Overall, sites with lower urchin densities showed better kelp survival and growth. These results suggest that exclusion devices alone may be insufficient in areas with intense grazing. Through this integrated modelling and experimental approach, this thesis delivers new tools and evidence-based insight to guide targeted and effective kelp restoration by identifying the drivers of grazing patterns and evaluating restoration techniques. More broadly, this work supports ecosystem-based management, species recovery, and climate resilience planning in Canada’s marine ecosystems.
An analysis of ocean alkalinity enhancement models and their limitations
(2025) Martin, Katherine Rena; Weaver, Andrew J.; Eby, Michael
As atmospheric carbon dioxide (CO2) levels continue to rise, increasing attention is being given to exploring mitigation techniques that could potentially enhance the natural drawdown of CO2. One such mitigative intervention is ocean alkalinity enhancement (OAE), which has drawn the scientific community's attention over the past decade, as a natural form of carbon capture and a hopeful solution to the excess carbon dioxide in our atmosphere. OAE involves dissolving alkaline materials into ocean surface waters to increase its natural CO2 buffering capacity. Limestone and lime have received plenty of attention given their widespread availability. Here, the following paper will address the order one policy-relevant question of whether OAE represents a viable CO2 removal solution to global warming. The UVic Earth System Climate Model (ESCM) was used to explore the potential of OAE interventions under representative concentration pathways (RCP) 2.6, 4.5, 6.0, and 8.5. For each RCP, three OAE interventions were implemented. First, it was assumed that the global annual production of limestone was crushed, uniformly distributed across the surface waters of the global ocean, where it immediately dissociates in the surface water. Second, it was assumed that the global production of limestone was converted to lime, with the CO2 released in this process being added to the atmosphere. In the third intervention, the second intervention was repeated, though sequestering the CO2 arising from lime production. Although lime and limestone OAE have been put forward as major solutions for carbon dioxide emissions, the results show that despite slightly raising pH, lowering CO2 concentrations and lowering air surface temperatures, the change is small, suggesting that OAE interventions have little potential for mitigating global warming.
Roll For perception: Games as a site of decolonization and social change
(2025) Riccitelli, Camryn; Rose-Redwood, Reuben Skye
Both tabletop and video games have immense potential to create opportunities for decolonization, education, and social change. They can be a highly engaging form of learning that allow players to deeply understand and connect with the games message or story, especially with complex and difficult subjects such as decolonization. They can create space and community for marginalized peoples (i.e. BIPOC, LGBTQ2+) and enable them to express themselves and tell their stories. This study explores how games created by or in collaboration with Indigenous and other marginalized peoples can challenge colonial values and binaries. Grounded in cultivation theory, which examines the lasting effects of media, the study draws upon semi-structured interviews with members of a local gaming community, the Galleon Gaming Society, as well as online game reviews and statements to explore the game-player relationship and how players interact within and around the game space. Looking at the role games play in decolonization efforts will help unravel colonial structures within today’s games and make gaming a more inclusive and enriching experience.

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