Graduate Theses & Dissertations

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Context Fear Memory
Distributing contextual fear episodes makes the memory become HPC-independent, meaning increasingly reliant on non-HPC memory structures. It is unclear, however, whether distribution of the conditioning episodes alone is sufficient or whether a combination of distribution and high conditioning saliency is necessary to make the memory become HPC-independent. To resolve this issue, rats were trained using a distributed contextual fear conditioning protocol in which foot-shocks were manipulated to create a low (0.4mA), intermediate (0.7 mA) and high (1.0 mA) saliency condition. This thesis also aimed to determine brain structures supporting the HPC-independent memory by assessing retention-induced c-fos expression in the basolateral- amygdala, perirhinal and anterior cingulate cortices. The results suggest that HPC lesion rats in the high saliency condition displayed similar level of freezing as control rats, indicating “strongly salient” and distributed episodes creates a HPC independent memory. c-fos expression suggests together, an increased context representation in the perirhinal and anterior cingulate cortices and a strengthened fear representation in the basolateral-amygdala supports the HPC-independent memory. Author Keywords: context fear memory, distributed reinstatements, hippocampus, IEG, rat, saliency
Supercritical Water Chemistry
Supercritical water (SCW) exhibits unique properties that differentiates it from its low temperature behaviour. Hydrogen bonding is dramatically reduced, there is no phase boundary between liquid and gaseous states, heat capacity increases, and there is a drastic reduction of the dielectric constant. Efforts are underway for researchers to harness these properties in the applications of power generation and hazardous waste destruction. However, the extreme environment created by the high temperatures, pressures and oxidizing capabilities pose unique challenges in terms of corrosion not present in subcritical water systems. Molecular Dynamics (MD) simulations have been used to obtain mass transport, hydration numbers and the influence on water structure of molecular oxygen, chloride, ammonia and iron (II) cations in corrosion crevices in an iron (II) hydroxide passivation layer. Solvation regimes marking the transitions of solvation based versus charge meditated processes were explored by locating the percolation thresholds of both physically and hydrogen bonded water clusters. A SCW flow through reactor was used to study hydrogen evolution rates over metal oxide surfaces, metal release rates and the kinetics for the oxidation of hydrogen gas by oxygen in SCW. Insights into corrosion phenomena are provided from the MD results as well as the experimental determination of flow reactor water and hydrogen chemistry. Author Keywords: Flow Studies, Molecular Dynamics, Supercritical Water
Altered Hippocampal Regulation of Immediate Early Genes after Pentylenetetrazol-Induced Seizures
Seizures induce long-term changes in gene expression in the hippocampus. Experimental evidence has demonstrated a significant effect of epileptic activity on the activity of neurons that participate in complex cognitive and behavioural processes. The present series of experiments involving kindling with subconvulsive doses of PTZ demonstrates a link between seizures and altered immediate early gene expression within the hippocampus and dentate gyrus. In addition, newborn hippocampal neurons were shown to have decreased induction of plasticity-related genes, suggesting deficits in activity-dependent recruitment. These findings may shed light on the mechanisms underlying epileptogenesis and epilepsy-related hippocampal dysfunction in human patients. Author Keywords: hippocampus, IEGs, kindling, neurogenesis, seizures
Assessing Molecular and Ecological Differentiation in Wild Carnivores
Wild populations are notoriously difficult to study due to confounding stochastic variables. This thesis tackles two components of investigating wild populations. The first examines the use of niche modeling to quantify macro-scale predator-prey relationships in canid populations across eastern North America, while the second examines range-wide molecular structure in Canada lynx. The goal of the first chapter is to quantify niche characteristics in a Canis hybrid zone of C. lupus, C. lycaon, and C. latrans to better understand the ecological differentiation of these species, and to assess the impacts of incorporating biotic interactions into species distribution models. The goal of the second chapter is to determine if DNA methylation, an epigenetic marker that modifies the structure of DNA, can be used to differentiate populations, and might be a signature of local adaptation. Our results indicated that canids across the hybrid zone in eastern North America exhibit low levels of genetic and ecological differentiation, and that the importance of biotic interactions are largely lost at large spatial scales. We also identified cryptic structure in methylation patterns in Canada lynx populations, which suggest signatures of local adaptation, and indicate the utility of DNA methylation as a marker for investigating adaptive divergence. Author Keywords: Ecological Epigenetics, Ecological Genetics, SDM
All Things Fusible
This dissertation presents the work of the American science fiction writer Neal Stephenson as a case study of mediations between literature and science by mobilizing its resonances with contemporary science studies and media theory. Tracing the historical and thematic trajectory of his consecutively published novels Snow Crash (1992), The Diamond Age; or, A Young Lady’s Illustrated Primer (1995), Cryptonomicon (1999), Quicksilver: The Baroque Cycle I (2003), The Confusion: The Baroque Cycle II (2004), and The System of the World: The Baroque Cycle III (2004), it approaches Stephenson’s fiction as an archaeology of the deep history of science that leads from late twentieth-century cyberculture, to world-war-two cryptography, and the seventeenth-century rise of the Royal Society. Refracted through a parallel reading of Stephenson’s novels and the theoretical work of Michel Serres, Bruno Latour, Friedrich A. Kittler, Isabelle Stengers, Donna Haraway, and others, this dissertation offers a literary discussion of the relations among cybernetics, complexity theory, information theory, systems theory, Leibnizian metaphysics, and Newtonian alchemy. Recognizing these hybrid fields as central to contemporary dialogues between the natural sciences and the humanities, Stephenson’s work is shown to exhibit a consistent engagement with the feedback loops among physical, artistic, narratological, and epistemological processes of innovation and emergence. Through his portrayal of hackers, mathematicians, natural philosophers, alchemists, vagabonds, and couriers as permutations of trickster figures, this dissertation advances a generalized notion of boundary transgressions and media infrastructures to illustrate how newness emerges by way of the turbulent con-fusion of disciplines, genres, knowledge systems, historical linearities, and physical environments. Uninterested in rigid genre boundaries, Stephenson’s novels are explored through the links among artistic modes that range from cyberpunk, to hard science fiction, historiographic metafiction, the carnivalesque, and the baroque. In a metabolization of the work performed by science studies, Stephenson’s fiction foregrounds that scientific practice is always intimately entangled in narrative, politics, metaphor, myth, and the circulation of a multiplicity of human and nonhuman agents. As the first sustained analysis of this segment of Stephenson’s work, this dissertation offers a contribution to both science fiction studies and the wider field of literature and science. Author Keywords: Complexity Theory, Cyberpunk, Michel Serres, Neal Stephenson, Science Fiction, Science Studies
Something out of Nothing? Place-based Resilience in Rural Canadian Youth
This dissertation explored how rural communities enhance the capacity of youth to both navigate and negotiate healthy identities and well-being in the context of social ecological resilience. Resilience refers to the capacity for individuals to have good outcomes in spite of exposure to significant adversity. Rural communities are often identified as places of deficit both in scholarly literature and in general social discourse which can constitute adversity. Given the importance of place as a social determinant of health, rural communities can have a notable impact on the positive development of adolescent identity and well-being of the youth that reside within them. Drawing on the concept of social ecological resilience which draws attention to the importance of environments and relationships to support development, this project engaged with high school aged adolescents (14 to 18 years old) from Haliburton County in Central Ontario. Leveraging mixed model methods, the project featured both quantitative and qualitative approaches. There were 63 participants (33 male, 28 female and 2 non-binary) for the quantitative phase of the research which made use of the Child and Youth Resilience Measure survey instrument. The second phase of the research was qualitative and featured 14 participants who engaged in six focus groups. The focus groups provided context specific awareness of place-based factors which participants found supportive in their development. The results indicated that while the overall resilience scores for the community were lower than the national average (t(62) = 3.20, p <0.01), some study participants found the community to be resilience bolstering. Specifically, participants recognized the importance of supportive people, an awareness of an enriched sense of community, and a powerful sense of the value of nature and the outdoors to be the most significant aspects for the development of their resilience. The results indicate that rural youth are not naïve to the complexity of their circumstances but are able to use their rural contexts to develop the capacity to negotiate and navigate towards healthy identities and well-being. Author Keywords: Adolescent, Place-based, Resilience, Rural, Social Ecological, Youth
Sextual Consent
The purpose of the current study was to explore the relationships between sexting, perceptions of sexual consent, and nonconsensual sexual experiences (NSEs). Participants consisted of 100 community members and 851 undergraduate students enrolled at Trent University. It was found that males were more likely than females to interpret ambiguous sexual scenarios as consensual, but consent perceptions were not influenced by sexting. When examining past personal experiences, males interpreted received sext messages as an indicator of consent significantly more than females, while females were more likely to interpret received messages as more harassing. NSEs were significantly related to sexting behaviours: those who engage in sexting were more likely to also have experienced a NSE, and 20.5% of participants in the current study reported having experienced a NSE with a consensual sexting partner. The current study has important implications for the future of sexting research, practice, and policy. Author Keywords: nonconsensual sexual experiences, sexting, sexual assault, sexual consent, sexual harassment
Reconceptualising the Heteronormative Curriculum Through Autobiographical Methodology - A Study of Heteronormativity within Ontario Ministry of Education Curriculum Documents
This thesis is about the negative impacts on queer identities caused by the lack of diversity related to sexual orientation within Ontario Ministry of Education curriculum documents, both at the elementary and secondary level. Curriculum documents as well as policy documents are analysed and compared in order to address the lack of diverse sexual orientation representation within Ontario’s education system. The study is guided by the question: “who benefits from the current representations of sexual orientation in the curriculum?” This conceptual study advances autobiographical methodology and the concept of Currere in relation to queer theory that allows researchers to analyse their educational experiences throughout the course of their lives and then become agents of social change. The results of my personal curriculum analysis have shown that curriculum documents lack diverse sexual orientation representation and that this has negative impacts how LGBQQ people identify and on the course of their lives. Author Keywords: Curriculum, Homophobia, LGBQQ, Ontario Curriculum, Ontario Education, Sexual Orientation
Eco-evolutionary Dynamics in a Commercially Exploited Freshwater Fishery
Fisheries assessment and management approaches have historically focused on individual species over relatively short timeframes. These approaches are being improved upon by considering the potential effects of both broader ecological and evolutionary processes. However, only recently has the question been raised of how ecological and evolutionary processes might interact to further influence fisheries yield and sustainability. My dissertation addresses this gap in our knowledge by investigating the role of eco-evolutionary dynamics in a commercially important lake whitefish fishery in the Laurentian Great Lakes, a system that has undergone substantial ecosystem change. First, I link the timing of large-scale ecological change associated with a species invasion with shifts in key density-dependent relationships that likely reflect declines in the population carrying capacity using a model selection approach. Then, using an individual-based model developed for lake whitefish in the southern main basin of Lake Huron, I demonstrate how ecosystem changes that lower growth and recruitment potential are predicted to reduce population productivity and sustainable harvest rates through demographic and plastic mechanisms. By further incorporating an evolutionary component within an eco-genetic model, I show that ecological conditions also affect evolutionary responses in maturation to harvest by altering selective pressures. Finally, using the same eco-genetic model, I provide a much-needed validation of the robustness of the probabilistic maturation reaction norm (PMRN) approach, an approach that is widely used to assess maturation and infer its evolution, to ecological and evolutionary processes experienced by exploited stocks in the wild. These findings together highlight the important role that ecological conditions play, not only in determining fishery yield and sustainability, but also in shaping evolutionary responses to harvest. Future studies evaluating the relative effects of ecological and evolutionary change and how these processes interact in harvested populations, especially with respect to freshwater versus marine ecosystems, could be especially valuable. Author Keywords: Coregonus clupeaformis, density-dependent growth, fisheries-induced evolution, individual-based eco-genetic model, Lake Huron, stock-recruitment
Securitization, Borders, and the Canadian North
Canada takes a national approach to border management. While this ensures that security practices are consistent across the country, it also fails to consider that different regions in Canada may have their own border needs. This dissertation, therefore, seeks to determine if border management priorities in Northern Canada are the same as in Southern Canada, along the 49th parallel. To make this determination, three sets of federal government documents are analyzed. First, documents associated with the current Beyond the Border Action Plan are explored to better understand security priorities and if regions are considered. Next, documents that are associated with Northern security and regional governance are analyzed in order to illuminate regional security issues and determine where borders fit within this narrative. The final set of documents to be examined are Senate reports on Northern security, as they can provide a glimpse into how regional security agendas are set. Grounded theory is used to illicit key themes from all documents and political discourse analysis is applied to the Senate reports to assess the strength of securitizing arguments for the region. Securitization theory and the Copenhagen School’s five security sectors are used to frame the analysis. This approach allows for a more comprehensive understanding of the region’s security priorities and the extent of the interplay between the sectors. The concept of regional security complexes is also addressed to determine the extent to which bilateral border cooperation exists in the North. Analysis reveals that border security priorities are not the same in the North as they are in the South. For example, in the North, greater emphasis is placed on protecting maritime borders, whereas in the South, land and air borders are prioritized. Beyond the Border aligns more closely with the needs of the Southern border, thus leaving a policy and security gap in the North. Bilateral border and security cooperation are also much more prevalent in the South than in the North. This research concludes with three policy suggestions to close this gap and addresses the extent to which it is in Canada’s interest to work more closely with the United States in the North. Author Keywords: Arctic, Borders, Canada, Policy, Regions, Securitization theory
From Toronto to Africville
How can educators use drama to nurture an ability in their students to identify and challenge the discourses and practices that have historically perpetuated oppression and inequality within Canada — without miring them in those narratives of oppression? This dissertation discusses the work of De-Railed, a theatre group that worked with youth in Hamilton Rapids, a Toronto neighbourhood where a high percentage of residents experience racial discrimination and poverty, to create a play about the destruction of Africville, a historically Black community in Halifax, NS. Drawing from the methodologies of critical, performance, and imaginative ethnography; critical multiculturalism; theatre of the oppressed; and feminist critical pedagogy, this dissertation argues that while participants used the fictional and intersubjective nature of drama to express embodied and affective resistance to class- and race-based oppressions in Canada’s past and present, the play-building process also reproduced certain unequal disciplinary structures that De-Railed was attempting to challenge. Emphasizing the importance of creating space for young people’s expressions of negative affect and emotion, this dissertation considers both the potentialities and limitations of De-Railed’s application of theatre of the oppressed methods in enabling participants to engage in affective expressions of resistance that may not have been permissible or available in other areas of their lives. Author Keywords: Africville, feminist critical pedagogy, forum theatre, multiculturalism, performance ethnography, theatre of the oppressed
Habitat Characteristics, Density Patterns and Environmental Niches of Indo-Pacific Humpback Dolphins (Sousa chinensis) of the Pearl River Estuary and Eastern Taiwan Strait
The purpose of this thesis is to quantify the habitat characteristics, density patterns and environmental niches of two groups of Indo-Pacific humpback dolphins: Chinese white dolphins (CWD) of the Pearl River estuary (PRE), and Taiwanese white dolphins (TWD, =Taiwanese humpback dolphin, THD) found in the eastern Taiwan Strait (ETS). Much work has already been done on the habitat use of CWDs in parts of the PRE, so the purpose of my first two chapters was to advance knowledge of the TWD to a comparable level. Chapter 2 contains the first published description of the relatively shallow, inshore, estuarine habitat of the TWD. General environmental characteristics and observed group sizes were consistent with other populations of humpback dolphins, and group sizes were not correlated with the environmental variables measured during surveys. Chapter 3 investigated density patterns of TWDs, finding spatiotemporal heterogeneity across the study area. Humpback dolphin densities fluctuated from year to year, but some parts of the study area were consistently used more than others. Environmental characteristics again did not influence dolphin densities, though more dolphins than expected were sighted in waters adjacent to major land reclamations, which may be related to the location of these areas close to major rivers. In Chapter 4, niches of the TWD and CWDs found in the PRE were compared using species distribution models, which indicated significant niche overlap. This may be due to niche conservatism maintaining similar fundamental niches between the two groups since their historical split >10,000 years ago, or a result of the intrinsic biotic factors that influence occurrence data affecting the hypervolume dimensions of each realized niche in similar ways. Geographic predictions indicate that most of the TWD’s range has likely been surveyed, and that there may be connectivity between PRE humpback dolphins and at least one neighbouring putative population due to continuous predicted suitable habitat in waters that remain poorly surveyed. Overall, my thesis demonstrates that density patterns may vary over time, but on a broad temporal scale, these two allopatric groups of Indo-Pacific humpback dolphins have similar habitat requirements in geographically isolated, but environmentally similar locations. Author Keywords: density, habitat, Indo-Pacific humpback dolphin, niche overlap, Sousa chinensis, species distribution model

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