English

We studied the physiological and molecular responses of lab-grown Daphnia pulex to shifts in dietary (carbon, nitrogen, phosphorus, and cyanobacteria) and growth media (calcium) nutrient supply using a set of potential biomarkers via qPCR. Each examined nutrient had a strong effect on Daphnia mass-specific growth rate, and we found significant dose-dependent effects of treatment level (medium and low) on the gene expression of selected indicator genes. Furthermore, linear discriminant analysis models using different combinations of treatment levels could separate the animals between nutritional treatments with 86-100% prediction accuracy. This would suggest that Daphnia appear able to respond to nutrient limitation by adjusting their growth rate and associated molecular pathways to deal with an insufficient supply of nutrients. While this study provides valuable information regarding Daphnia's ability to adjust physiological and molecular processes under controlled laboratory conditions, more validation needs to be conducted before applying these potential biomarkers to wild populations to assess the type and intensity of nutritional stress.

Petroleum coke (petcoke) is a waste by-product of the upgrading process in the oil refining industry. It has limited utility in other areas of application.1 High carbon content (over 85 wt.%), low ash content, and softness make petcoke a potentially valuable precursor for graphitization, where amorphous carbon can be transformed into graphitic carbon. The synthetic production of graphite is gaining more interest due to the increasing demand for battery materials.2,3 Without metal moderators, achieving graphitization requires significantly high temperatures (> 2500 °C). Magnesium (Mg) has been identified as a promising reactant because of its efficacy in promoting graphitization and its relatively simple removal from the final product.3–5 The optimized conditions of magnesium-assisted graphitization showed an electrical conductivity of (3552.0 ± 78.5) S/m at 10 mA. Furthermore, bimetallic metal mediators can exhibit improved catalytic activity in graphitization due to the synergistic effect.3,6,7 Raney nickel alloy (Ni-Al alloy) contains 50 wt.% nickel and 50 wt.% aluminum. Individually, nickel and aluminum have shown efficacy in graphitization.8 However, no research has been conducted on the efficacy of Raney nickel alloy as a metal mediator in petcoke graphitization. We present our work on the graphitization of petcoke and its derived activated carbon using magnesium and Ni-Al alloy at 1000 °C and 1500 °C, respectively. This study assesses the effects of heating time, temperature, and precursor particle size on the degree of graphitization. Additionally, magnesium was completely removed after the graphitization process, and the residual Raney nickel alloy percentage was minimal.

Author Keywords: activated carbon, magnesium, Petroleum coke, Raney nickel alloy, synthetic graphitization

Population cycles are characterized by predictable temporal oscillations in population size and are influenced by densities of both predators and prey. These oscillations are influenced by the predator functional response, i.e. the influence of prey density on predator kill rate. The Canada lynx (Lynx canadensis) is a predatory mammal with cyclic northern populations driven by snowshoe hare (Lepus americanus) density. Despite some understanding of the drivers of lynx cycles, we lack understanding of how lynx hunting behaviour, including kill site selection, is influenced by the spatio-temporal distribution of prey. These concepts are explored in chapter one of this thesis.

In chapter two, we (coauthors and I) built on work in Kluane region of the Yukon where lynx and hare populations have been tracked through several population cycles. Over six winters, we deployed GPS collars on >40 individual lynx, some of which were fitted with satellite transmitters, accelerometers, and audio recorders. We validated the use of these technologies for identifying hare kills with an accuracy of >87%. This validation is the foundation for chapter three of this dissertation.

In chapter three, we investigated the drivers of spatial variation in lynx kills. Using snow track transects through four winters of declining hare density, we developed a robust model of habitat-specific hare abundance over time. Using model predictions, in combination with lynx Utilization Distributions derived from GPS locations and related habitat associations, we determined the importance of hare abundance, lynx spatial use, and landscape characteristics such as vegetation density in determining patterns of lynx kills and space use. Lynx kill sites were most strongly predicted by lynx space use, followed by the relative abundance of hares, an index of tree cover density, and elevation. Lynx space use itself was not strongly predicted by hare relative abundance, but rather by a shift to the use of more open habitats when hares were abundant to higher use of denser habitats as hare populations declined; this apparently corresponded to temporal changes in hare distribution. This thesis helps to disentangle the drivers of spatio-temporal variation in predator foraging behaviour, with important implications for understanding predator-prey dynamics.

Author Keywords: animal behaviour, biologging, foraging, habitat selection, Lynx canadensis, predator-prey dynamics

Flavohemoglobins are enzymes primarily implicated in nitrosative stress due to their high nitric oxide (NO) dioxygenase activity and transcriptional upregulation in response to NO. Giardia intestinalis assemblages A, B, and E possess flavohemoglobins (gFlHb) that may function beyond their NO dioxygenase activity, potentially contributing to oxidative stress regulation, as transcriptional profiling revealed that peroxide also induces gFlHb expression. This study investigates gFlHb's NADH oxidase activity in the absence of NO, structural interactions with lipids, and response to reactive oxygen species. Minor differences in NADH oxidase activity among assemblages were observed, and their susceptibilities to inhibition were assessed to evaluate gFlHb as a potential therapeutic target against Giardia infection. Under aerobic conditions, we observed that gFlHb generates hydrogen peroxide, a surprising finding suggesting a self-regulating feedback mechanism involving reactive oxygen species and heme degradation. These findings provide new insight into the role of flavohemoglobins in microaerotolerant parasites like Giardia.

Author Keywords: flavohemoglobin, Giardia intestinalis, heme, hydrogen peroxide, NADH, oxidative stress

Transracial adoption places the child with a family of a different ethnicity than their own. In the current study we qualitatively examine concerns associated with transracial adoption and investigate the relation between parent-child relationships and child social-emotional problems. Twenty-two adopted girls from China, 20 nonadopted Caucasian girls, and 23 nonadopted Chinese-Canadian girls, between 10-14 years, and their mothers were included. Thematic content analysis of interviews with adoptive mothers revealed that the transracial adoption experience had positive, negative, and neutral aspects. This included the parent-child relationship, the adopted child's view of their physical appearance, and the incorporation of cultural elements into the home. Quantitative analyses revealed no significant differences between the three groups on measures of parent-child relationship quality and child social-emotional functioning, which confirmed findings from the qualitative analysis. In the entire sample there were significant negative relations between quality of parent-child relationship and social-emotional functioning. These results suggest that early age of adoption may help decrease the likelihood of problematic parent-child relationships and social-emotional functioning in adopted children. It would be important to re-examine this question during adolescence when racial identity forms.

Author Keywords: Cultural Socialization, Developmental Psychology, Parent-Child Relationship, Social-Emotional Behaviour, Transracial Adoption

DNA methylation (DNAm) is a useful indicator of phenotypic expression and diversity, and can potentially inform adaptations to environmental changes. This thesis uses epigenetic techniques to investigate the mechanisms underlying phenotypic variation in white-tailed deer, black bear, and mountain goat, with a particular focus on age and body size. In the second chapter, we aimed to contribute to wildlife monitoring by developing epigenetic clocks, or predictive models of age, and diagnostic markers of age class and sex. In the third chapter, we aimed to investigate the involvement of DNAm in body size variation of white-tailed deer by developing a model predictive of hindfoot length, and by identifying CpGs and genes that may be involved in hindfoot length variation. My results indicate that DNAm is an effective predictive marker of various phenotypes in these North American large mammals, and that epigenetic methods offer valuable insights for managing human impacts on wildlife.

Author Keywords: Age, Body Size, DNA Methylation, Epigenetics, Phenotypes, Population Genetics

A new regime governing cannabis production, distribution, and access came into effect across Canada in 2018. With the passing of the Cannabis Act (2018) a new legal cannabis industry began taking shape across the country, with specific manifestations at the local and provincial levels. In this study, I take up the standpoint of people who use cannabis and explore how access is organized under this new regulatory regime. Following a new-materialist informed institutional ethnographic mode of inquiry, I draw on interviews, observations, and texts to describe the work processes through which three distinct materializations of cannabis are produced: cannabis for medical purposes, retail cannabis products, and cannabis as a corporate good. My analysis then reveals how these materializations are organized according to discourses of medicalization, commercialization, and corporatization in ways that curtail the full liberatory potential of this policy change.

At its core my research is an investigation into the operations of the cannabis industry in Ontario, Canada – currently one of the largest legal cannabis markets in the world. My intent is not to provide a view of the functioning of the industry as a whole. Rather, it is to tease out key operations, including medical access programs, product selection and testing practices, and knowledge practices, and explore both their impacts on people who use cannabis and what insights they hold for reorganizing access to other controlled substances. Importantly, my research demonstrates how state actors and corporate entities remain the main beneficiaries of legalization, which I argue is the result of an over-reliance on state regulation over community organization as the schema for enacting a public health approach to drug policy. While cannabis legalization may not have realized its full liberatory potential in this country, it has offered an invitation to reconsider the criminalization of previously controlled substances and how we might regulate these substances in new ways. In the conclusion to this work I take up this invitation, building on my findings to imagine what the organization of cannabis access outside current ruling relations could look like and how we might cultivate care-full relations of drug access more broadly.

Author Keywords: Canada, Cannabis, Drugs, Institutional Ethnography, New Materialisms, Policy

Indigenous children and youth have been exposed to educational institutions and curricula that are detrimental to their identity and cultural journey. This thesis explores the importance of educational institutions and curriculums complementing the needs of Indigenous students during their time in compulsory and post-secondary education. Five self-identifying Indigenous students attending Trent University share their educational experiences using sharing circles. Following this, the findings are analyzed, and recommendations for educational policies are discussed.

Author Keywords: Colonization, Indigenization, Indigenous education, Indigenous identity

The diversification of mammals has been shaped by climatic fluctuations and geological changes over millions of years. Among them, shrews (Soricidae) stand out as one of the most diverse mammalian lineages. Shrews are found on most continents and have evolved remarkable adaptations at the species and population levels. Although evolutionary studies of shrews have been limited by a lack of genomic resources, this work aimed to address this gap by developing such resources and using various omics approaches to explore adaptation and divergence in shrews, with a particular focus on an isolated population on Bon Portage Island (BPI), Nova Scotia, Canada. BPI shrews exhibit distinctive foraging habits and possess a unique allele for a dietary enzyme, which may represent an adaptation to their specialized diet. My research involved assembling and annotating de novo genomes from three shrew species. In Chapter 2 I conducted a comparative genomic analysis of 20 mammals (including four shrew species) to identify lineage-specific adaptations including accelerated regions, gene family expansions, and positively selected genes. I found shrew-specific variants in genes associated with the nervous, metabolic, and auditory systems, which may underlie some of their unique traits. In Chapter 3, I examined morphological and epigenetic divergence between mainland and island populations of masked shrews (Sorex cinereus), including BPI. Island shrews exhibited smaller body sizes and signs of accelerated biological aging, marked by DNA methylation differences enriched in developmental and digestive pathways. Chapter 4 focused on analyzing genome-wide SNP data to identify regions of differentiation, alongside RNA-seq data to perform a differential gene expression analysis between BPI shrews and other populations. The results from both analyses revealed patterns of differentiation in genes associated with fatty acid metabolism and metabolic regulation that are likely linked to their specialized, largely marine-based diet. Additionally, I reconstructed the demographic history of Nova Scotia masked shrew populations, revealing that the divergence of the BPI population appears to coincide with rising sea levels following the last glacial maximum. These findings shed light on mechanisms of adaptation and divergence, illustrating how ecological pressures, geographic isolation, and dietary specialization shape genomic, epigenomic, and transcriptomic landscapes.

Author Keywords: comparative genomics, epigenetics, genome assembly, island syndrome, population genomics, transcriptomics

In electron-doped ferroelectrics, the free electrons can become concentrated along the domain walls which act like a conducting surface. We consider the impact of free electrons occupying the t2g orbitals on the domain walls of an electron-doped perovskite ferroelectric. We build an analytical model based on Landau-Ginzburg-Devonshire theory, and a trio of tight-binding Hamiltonians for free electrons. We self-consistently solve for the polarization, potential, and electron density using a finite-difference approximation. We find that the ferroelectric is effectively charge neutral. The free electrons are attracted to the positively-charged domain wall, leaving it with a small residual charge. As the electron density increases, the domain walls tilt to form zig-zag domain walls. Orbital selectivity of the t2g orbitals depends on the relative orientations of the orbital plane and the domain wall. This property influences the rate at which the domain wall tilts as a function of the electron density.

Author Keywords: Charged Domain Wall, Domain Wall, Ferroelectric, Landau-Ginzburg, Perovskite, Strontium Titanate