Trent University

This study examines the experiences of Tamil Canadian caregivers providing home care for older adults with dementia, highlighting their unique challenges. Grounded in a social constructivist and phenomenological approach, the qualitative research explores the influence of social, cultural, and familial expectations on caregiving roles. Semi-structured interviews with ten Tamil Canadian caregivers revealed difficulties in accessing healthcare, managing complex care needs, and balancing personal well-being with caregiving responsibilities. Language barriers and limited awareness of available health and social services further exacerbated emotional, financial, and physical burdens. Caregivers expressed a strong need for educational resources to enhance their skills and support their roles. Despite these challenges, participants reported emotional rewards, such as strengthened family bonds and a profound sense of duty. The study underscores the importance of tailored interventions, advocating for culturally responsive services, language support, and caregiver education to better address the needs of Tamil Canadian caregivers.

Author Keywords: caregiver burden, cultural barriers, cultural values in caregiving, language barriers, self-care for caregivers., tamil Canadian caregivers

Methylobacterium spp., a dominant and functionally conserved group of plant-associated bacteria, have long been recognized for their roles in promoting host growth, stress tolerance, and phytohormone modulation. This body of work collectively repositions Methylobacterium not only as a plant growth-promoting genus but also as a promising agent of microbiome-mediated crop protection. Across several investigations, the ecological, biochemical, and functional attributes that underpin this potential were examined, with specific focus on hormone production, compatibility with agrochemical inputs, and antifungal activity.

A comprehensive inventory of 46 Methylobacterium strains revealed widespread production of cytokinins – including highly active forms such as trans-zeatin – and variable capacities to synthesize indole-3-acetic acid. Cytokinin output increased under carbon-limiting conditions, highlighting the genus's adaptive hormonal response. Parallel investigations demonstrated that commercial glyphosate-based herbicide formulations significantly inhibited the growth of most Methylobacterium strains, whereas pure glyphosate alone showed negligible toxicity. Key findings of experiments indicate that non-active formulation components participate in the disruption of beneficial bacteria by facilitating higher intracellular glyphosate concentrations and subsequent toxic effects. This introduces a novel link between agrichemical formulation practices and the selective disruption of keystone microbial taxa.

Contrastingly, fungicide compatibility testing showed that Methylobacterium strains tolerate key fungicides such as azoxystrobin, fludioxonil, and metalaxyl-M, supporting their inclusion in integrated pest management frameworks. Subsequent functional antagonism assays further revealed that specific Methylobacterium isolates inhibit phytopathogenic Fusarium species in vitro and in planta. Notably, M. organophilum enhanced soybean seedling vigor and reduced disease severity when co-inoculated with F. graminearum by preserving the integrity of the seed coat, demonstrating protective activity with unique mechanics.

Finally, differential hormone profiling at the pathogen-antagonist interface revealed that biocontrol-effective Methylobacterium strains not only produce higher levels of auxin and salicylic acid but also induces jasmonic acid production – likely derived from Fusarium – suggesting complex cross-signalling and interference with fungal development and sensing pathways. Together, these findings advance our understanding of Methylobacterium as a keystone genus in the phytobiome, capable of contributing to both plant vigor and pathogen suppression and reinforce its relevance in the design of next-generation biocontrol strategies.

Author Keywords: agrochemical interactions, biological control, Fusarium antagonism, Methylobacterium, phytobiome, phytohormone signalling

The Wabigoon River is known for an historic mercury (Hg) pollution source, caused by a chlor-alkali facility operating in the 1960s. As legacy Hg contamination continues to cause serious adverse health effects to the local communities living in the Wabigoon River region, it is imperative to undertake additional research to understand the deposition and transport of historical mercury in this system and more importantly, its conversion into methylmercury (MMHg) which renders it bioavailable for ongoing bioaccumulation. The aim of this dissertation was to evaluate the transport and accumulation of Hg species by doing a spatial and temporal analysis of concentrations of mercury and methylmercury along the Wabigoon River, as well as assessing rates of methylation and demethylation, identifying areas of higher methylmercury production. Results show that locations downstream from the pollution source still show elevated mercury concentrations, with levels at least five times higher in water and up to 134 times higher in sediments compared to background levels. Among selected study sites, the Hydroelectric dam, the Wabigoon Rapids wetland and Clay Lake were identified to have high capacity for methylmercury production in the system, with notably Clay Lake presenting a higher potential for methylmercury accumulation due to the observed lower methylmercury demethylation rate. Furthermore, the impact of wetting and drying cycles on Hg methylation in riverbed and wetland locations within the Wabigoon River system was investigated through a laboratory simulation. Findings indicated increased susceptibility of riverbed locations to wetting and drying cycles.

Author Keywords: Demethylation, Mercury, Methylation, Methylmercury, Wabigoon River

The successful settlement of international students is important to their academic success as well as their integration into the host community. This thesis attempts to investigate the settlement needs and experiences of African international students in Peterborough, Canada, from a transnationalism perspective. Surveys were used to collect data from 351 students. A chi-square tests and multivariate ordinal logistic regression were used for the data analysis.The findings reveal that African International Students engage in a variety of transnational activities including, contacting family and friends at home, attending religious and cultural events, and eating traditional food which contribute to the settlement of African International Students. On the other hand, sending money and investing in one's home country were found to hinder the settlement of African International Students in Canada. This study contributes to the existing literature on international education and transnationalism and makes recommendations for policy makers and educational institutions.

Author Keywords: African International Students in Canada, International Student Migration, Settlement Process, Transnationalism

A meta-analysis revealed that while there is often a greater degree of contamination of soils and sediments with metals, contamination by mercury (Hg) is a large concern owing to its toxicity at low concentrations. The case study in Guyana characterized Hg and concentrations of other metals (As, Cd, Co, Cu, Mn, Ni, Pb, and Zn) in soil and sediment within gold mined areas. Metal concentrations were low in soil and sediment of sampled gold mines, while the concentrations of Hg were much higher in soil and sediment and contamination was not localized to the mine site. Moss bags and Hg passive air samplers (MerPAS) were deployed to measure atmospheric Hg around a gold mine in Mahdia, Guyana over a 90-day period as well as a 2-day period that encompassed a periodic burn (typically 2-hr). Mercury in moss and MerPAS were positively correlated over both deployment periods, but Hg concentrations measured during the 2-day event were several-fold higher in both moss and MerPAS compared with the 90-day exposure demonstrating that most of the Hg sorbed to both moss and passive samplers is lost during periods of inactivity. Using the 2-day deployment as a conservative estimate of atmospheric Hg exposure, Hg air concentrations around the burning station exceeded 100,000 ng m-3 averaged over a 48-hr period, and moss Hg concentrations were greater than 250,000 ng g-1 around the burning station, although Hg concentrations in both media decreased rapidly with distance. Mercury concentration in soil and sediment was strongly related to organic matter content, which tended to be higher away from the mine site. These controls of organic matter (carbon; C) cycling on Hg distribution and movement are clear at sites exposed to high atmospheric Hg and exist at the global scale, although Hg:C ratios in environmental media are greatly elevated at the gold mine site compared with the global average. Locally sourced biochar did not sufficiently improve physical properties (porosity) in overburden soil, which showed the worse plant response, possibly due to the high clay content that contributes to the "baked" condition of these soils and restrict root growth.

Author Keywords: Biochar, Environmental contamination, Gold mining, Mercury, Metals, Organic matter

Access to human blood for forensic research and training in bloodstain pattern analysis (BPA) can be difficult due to many ethical, safety and cost concerns. Mammalian blood alternatives can be sourced, especially from local and willing abattoirs, but some concerns remain, and the added difficulties of high variation and species-specific differences in cellular components pose other issues. Therefore, synthetic alternatives to human blood provide practical options for the BPA community. This thesis explores the use of alginate hydrogels as a base material for forensic blood substitute (FBS) development. Hydrogels are first explored as a suitable environment for DNA stability and functionality and compared to other polymer systems. The ability of DNA to remain intact while undergoing electrospray ionization (ESI) is also investigated. The FBS design focuses on mimicking the fluid properties and genetic capabilities of whole human blood – a material not developed in FBSs previously. ESI was used to develop microparticles (MPs) that serve as cellular components of human blood (the red blood cells – RBCs, and white blood cells – WBCs). The microparticles were ionically crosslinked using calcium to provide small MPs (RBCs) or covalently crosslinked with functional DNA to provide larger WBC-like functional particles. The integration of these novel MPs into alginate-based materials is optimized and their use in BPA scenarios is explored. The FBS is tested in BPA scenarios of dripping experiments, impact patterns, and the ability to extract and amplify the contained DNA. In addition, the stability (or shelf-life) of the FBS was also assessed. The FBS exhibited similar spreading ratios to blood and demonstrated feasibility in use for impact angle (a) determination and impact pattern creation. Importantly, the DNA contained within the FBS could be processed with analogous protocols used in DNA evidence processing, enhancing its applicability to BPA research and training.

Author Keywords: Alginate hydrogels, Bloodstain pattern analysis, Electrospray ionization, Forensic blood substitutes, Forensic materials, Synthetic DNA design

Recent developments in Artificial Intelligence (AI), particularly Large Language Models (LLMs), have provided powerful tools for Natural Language Processing (NLP) tasks like sentiment analysis. However, their fine-tuning and deployment present challenges, specifically in terms of computational efficiency and high training costs. To address these challenges, this work applies optimization techniques such as Quantized Low-Rank Adaptation (QLoRA) for parameter-efficient fine-tuning, followed by Generalized Post-Training Quantization (GPTQ) on the Llama 3.1 LLM. To evaluate these optimizations, we apply the model to a practical task: hate speech detection, using a curated dataset comprising of X (formerly Twitter) posts. Overall, the optimized model achieved a 67% reduction in size along with significant improvements in classification accuracy and inference speed compared to the base model.

Author Keywords: Generalized Post-Training Quantization, Large Language Models, Low-Rank Adaptation, Parameter-Efficient Fine-Tuning, Quantized Low-Rank Adaptation

Objectives/purpose: This study examined the psychosocial health (including resilience, hope, social functioning, mental wellbeing, and stress) of childhood cancer patients attending a recreational oncology camp (ROC).Methods: Childhood cancer patients enrolled for ROC participated in a survey on the first (T1) and last (T2) day of camp, and 3 months post-camp (T3). This survey included the: Child and Youth Resilience Measure (CYRM), Children's Hope Scale (CHS), Social Provisions Scale (SPS-5), and Short Warwick-Edinburgh Mental Wellbeing Scale (SWEMWBS). Afternoon saliva samples were collected at T1 and T2 to determine cortisol (ELISA). Results: CYRM, SPS-5, and SWEMWBS scores were high but did not differ between timepoints. CHS scores at T3 were lower compared to T1 and T2 (F=9.388, p=0.008). Salivary cortisol levels were within normal ranges. Conclusion/clinical implications: Childhood cancer patients have high levels of positive psychosocial variables and normal stress levels while attending ROC.

Author Keywords: cancer, children, hope, oncology camp, psychosocial health

We study a one-dimensional Fermi-Hubbard model with disorder in charge and spin degrees of freedom. We calculate the time dependence of the entanglement entropy. While previous research on disordered interacting systems has typically focused on systems with either charge or spin, our model enables us to explore the interplay between charge and spin in shaping the behavior of entanglement. We use a method that identifies optimally local charge- and spin-specific integrals of motion. We ask how the locality level of these integrals of motion influences the capacity of low-order terms in the l-bit Hamiltonian to capture the entanglement entropy. Our results show that increasing the locality level improves the accuracy of low-order terms in capturing entanglement entropy dynamics. With equally strong charge and spin disorder, the behavior of the entanglement entropy closely resembles that observed in single-degree-of-freedom systems, and the l-bit Hamiltonian truncated at second order accurately captures this behavior.

Author Keywords: Entanglement Entropy, Fermi-Hubbard Model, Hungarian Algorithm, l-bit Hamiltonian, Local Integrals of Motion, Many-Body Localization

The spectral properties of time series data reveal underlying processes but require complete datasets, often unavailable due to missing values and irregular sampling.This thesis uses a computational simulations framework to evaluate the perfor- mance of the Hybrid Wiener Interpolator [3], a novel method designed to reconstruct nonstationary time series data, thus making said data amenable for spectrum analysis. This research evaluates the Hybrid Wiener Interpolator's ability to handle nonstation- ary data and data gaps, comparing its performance to other interpolation methods under different stationarity and data integrity conditions. The results illuminate the robustness of this interpolator in scenarios typical of scientific datasets, offering a promising approach for enhancing spectrum estimation in the presence of non-ideal data conditions

Author Keywords: ARIMA Models, Data Imputation, Interpolation, Stationarity, Time Series, Time Series Simulations