Graduate Theses & Dissertations

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Speciation of Aluminum and Zinc in Three Streams of a Forested Catchment of the Boreal Zone
This study presents a detailed assessment of the chemical speciation of aluminum and zinc in three streams of a small, acid-sensitive forested catchment on the southern edge of the Precambrian Shield. Speciation analysis was achieved using an in-situ analytical technique known as Diffusive Gradient in Thin film (DGT) which measures labile metals, and a predictive computer algorithm (WHAM VI) which calculates metal species concentrations. Three types of DGT with different metal scavenging capabilities were used and a total of 11 deployments performed across four seasons. WHAM VI predictions showed that the organic fraction of aluminum was the main contributor to the dissolved concentrations in the main inflow stream (PC1) (~ 80 %) and the lake's outflow (PCO) (~ 75%); in the upland stream (PC1-08) the inorganic fraction contributed ~ 75%. For zinc the free ion was the single most important contributor to the dissolved concentration (< 90%) in all three streams. A comparative study of the DGT and WHAM methods showed an agreement between their inorganic concentrations during the spring season. Both methods indicate the greatest environmental impact for Al takes place during snow melt period in PCO and PC1-08 and in the summer for PC1. The greatest environmental impact for Zn predicted with WHAM VI, occurs during the spring in all three streams. Author Keywords: Aluminum, DGT, Metal speciation, WHAM, Zinc
Cytokinin Oxidase/Dehydrogenase (CKX) Gene Family in Soybeans (Glycine max)
Glycine max (soybean) is an economically important plant species that registers a relatively low yield/seed weight compared to other food and oil seed crops due to higher rates of flower and pod abortion. Alleviation of this abortion rate can be achieved by altering the sink strength of the reproductive organs of soybeans. Cytokinin (CK) plays a fundamental role in promoting growth of sink organ (flowers and seeds) by increasing the assimilate demand. Cytokinin oxidase/dehydrogenase (CKX) is an enzyme that catalyses the irreversible breakdown of active CKs and hence reduce the cytokinin content. The current thesis uncovers the members of CKX gene family in soybeans and the natural variations among CKX genes within soybean varieties with different yield characteristics. The identification of null variants of OsCKX2 that resulted in large yield increases by Ashikari et al. (2005) provided a rationale for current thesis. The soybean CKX genes along with the ones from Arabidopsis, Rice and Maize were used to construct a phylogenetic tree. Using comparative phylogeny, protein properties and bioinformatic programs, the potential effect of the identified natural variations on soybean yield was predicted. Five genes among the seventeen soybean CKXs identified, showed polymorphisms. One of the natural variations, A159G, in the gene GmCKX16 occurred close to the active site of the protein and was predicted to affect the activity of enzyme leading to higher accumulation of CKs and hence increased seed weight. Use of such natural variations in marker assisted breeding could lead to the development of higher yielding soybean varieties. Author Keywords: CKX, Cytokinins, Seed weight, Seed Yield, SNPs, Soybeans
Molecular Dynamics Simulations of Aqueous and Confined Systems Relevant to the Supercritical Water Cooled Nuclear Reactor
Supercritical water (SCW) is the intended heat transfer fluid and potential neutron moderator in the proposed GEN-IV Supercritical Water Cooled Reactor (SCWR). The oxidative environment poses challenges in choosing appropriate design materials, and the behaviour of SCW within crevices of the passivation layer is needed for developing a corrosion control strategy to minimize corrosion. Molecular Dynamics simulations have been employed to obtain diffusion coefficients, coordination number and surface density characteristics, of water and chloride in nanometer-spaced iron hydroxide surfaces. Diffusion models for hydrazine are evaluated along with hydration data. Results demonstrate that water is more likely to accumulate on the surface at low density conditions. The effect of confinement on the water structure diminishes as the gap size increases. The diffusion coefficient of chloride decreases with larger surface spacing. Clustering of water at the surface implies that the SCWR will be most susceptible to pitting corrosion and stress corrosion cracking. Author Keywords: Confinement, Diffusion, Hydration, MD Simulations, Supercritcal Water
Unexpected Journeys
The last two decades have seen thousands of Canadian university graduates go to teach English in places such as China, South Korea, and Japan. In this thesis, drawing on Clandinin and Connelly's concept of narrative inquiry, I situate the stories I heard about the experiences of 15 teachers who taught English as a Second Language in South Korea between 2003 and 2012. While my interviewees expressed intrinsically personal reasons for taking on such temporary professional employment, they also acknowledged that they felt somewhat forced to do so by an increasingly bleak job market at home. I position their decisions in the neoliberal employment context in Canada over the past two decades, highlighting the personal and socioeconomic factors that influenced them to take up such opportunities. Additionally, I examine how these experiences shifted their views of Canada and what it meant to be Canadian, both while they were away and upon their return home by revealing the contradictions between expectation and the lived realities of young Canadians. These contradictions unmask the deceptive nature of dominant narratives in Canadian society. Author Keywords: Canadian Identity, Canadian Job Market, Narrative, Neoliberalism, Teaching Abroad
Return to "The Child"
Despite - or perhaps because of - her popularity as a best-selling poet, the work of Mary Oliver has been minimized and marginalized within the academy. Nevertheless, Oliver's readership is an expansive and devout one made up of a wired yet insular North American public in search of reconnecting with the natural world. I propose that through Oliver's poetry readers access the affective, sensory responses to nature first encountered during childhood. This return to "the child" is deliberately used by various publics to share communal goals. Drawing from such frameworks as ecocritical and trauma theory, I explore environmental memory, ecstatic places, and the sensuousness of nature and language to consider ways in which diverse publics claim and use Oliver's work. I provide a close reading of selections of Oliver's poems to argue that her work's appeal speaks to a revived perception of the necessity of nature to the human spirit Author Keywords: Attentiveness, Childhood, Language, Mary Oliver, Nature Poetry, Senses
Role of Multiple Nights of Sleep in the Consolidation of an Engaging and Complex Motor Learning Task
The present study examined the role of multiple nights of sleep in the consolidation of a complex motor learning task. Participants were 24 Trent undergraduates, 12 in the learning group (Mage = 20.33, SD = 1.87, 10 female) and 12 in the control group (Mage = 21.92, SD = 3.42, 7 female). Participants underwent 5 consecutive nights of polysomnographic recordings, with a Rock Band learning session on the third night. A series of 2(group)x4(night) ANOVAs were performed on the sleep variables. Interactions were found in the number of spindles detected at Pz, F(333) = 9.19, p <.01, and in the density of spindles detected at Pz, F(3,33) = 4.06, p <.05. The pattern of changes from baseline was significantly different between the two groups; spindles increased in the learning group and decreased in the control group. The novel finding was that spindle number/density remained elevated at the third post-learning night of sleep. Author Keywords: Motor Learning, Procedural Memory, Sleep, Sleep Spindles
BACKGROUND PRACTICES, AFFORDANCES, AND THE FRAME PROBLEM
This project is a Heideggerian critique of the subject/object metaphysic presupposed in the Representationalist claim that the world is made intelligible solely in virtue of internal states that bear representations. It is comprised of two sections. The first is a critique of the ontological primacy of representational-intentionality/action in which I argue that where Brentano, Husserl, and Searle have erred is not in their model of intentionality/action, but in assigning a priori status to a derivative mode of being. The second is a critique of representation-driven artificial intelligence whereby I argue that belief-fixation and action selection that is context-dependent produces an insurmountable problem that prevents the parsing of context-specifying relevance; the corollary being that the world is not disclosed despite that system having a structurally isomorphic internal constitution to that which is purported by the Representationalist to obtain in human beings. With the issue thus framed, I conclude by arguing that this problem is dissolved within a Heideggerian phenomenological framework. Author Keywords: Artificial Intelligence, Heidegger, Phenomenology, Representationalism, Skillful Coping, The Frame Problem
(un)Natural Provocation
My thesis examines anthropomorphism and many avenues in which humans represent nonhumans to evaluate their own lives. Using Isabella Rossellini's Green Porno webseries, a collection of two-minute films starring Rossellini as a multitude of nonhumans with costumes transforming her into nonhuman, I posit that a new form of anthropomorphism -- one that values the nonhuman in all his or her nonhumanity -- is emerging in contemporary media. Rossellini describes the mating, seduction, and maternal instincts of these nonhumans, regularly drawing parallels between nonhuman and human behavior and uncovering crucial intersections in femininity, masculinity, queer theory, and abjection. In more recent films, I see Rossellini performing certain nonhumans to critique particular characteristics of Western human society and incredulously addressing the human viewer as a member of a species that might not be as high in the caste system of living beings as he or she is led to believe. In turning this sense of grotesque Otherness onto the human, I identify Rossellini as engaging in counterabjection, or the reversal of extreme degradation often projected upon nonhuman bodies by humans. Author Keywords: abjection, animal studies, nonhuman, queer studies
American Acropolis, American Ruins
Since 1979, photographer and sociologist Camilo José Vergara has taken repeat photographs of American cities in decline, focusing on evolving landscapes of postindustrial decay. Vergara's images subscribe to an aesthetic of ruin while providing a record of America's crumbling ghettos rooted in social documentary concerns. Vergara's work diverges from the ahistorical tendencies of contemporary ruin porn photography: by challenging the photograph's temporal stasis Vergara bears witness to the ongoing reality of disenfranchisement, assembling an archive that takes up the Benjaminian task of doing history in images. Vergara's photographs challenge standard photojournalistic portrayals of violence, particularly the ways in which `violent' African American and Hispanic inner city populations have been erroneously cast as the cause of their own economic misfortune. The Invincible Cities website assists Vergara in drawing attention to forgotten places but also complicates his mandate to engage outside viewers by distancing them from the real-­world environments his photographs portray. Author Keywords: Camilo José Vergara, imagistic history, postindustrial decline, repeat photography, ruin porn, Walter Benjamin
Carbon and Nitrogen Isotope Changes in Streams along an Agricultural Gradient
Nitrogen is a major constituent of agricultural fertilizers, and nitrogen inputs to stream water via runoff and groundwater lead to a variety of negative environmental impacts. In order to quantify the movement of nitrogen through aquatic food webs, fourteen streams with varying land uses across South-Central Ontario were sampled for two species of fish, freshwater mussels, and water for measurement of isotope ratios of δ15N and δ13C. I found that nitrogen isotopes in fish, water, and mussels were related to the percentage of riparian monoculture, and that carbon isotopes were unrelated to monoculture. Though all species were enriched as monoculture increased, the rate of δ15N enrichment as monoculture increased did not vary between species. This study has improved our understanding of how monoculture affects nutrient enrichment in stream food webs, and assesses the validity of using nitrogen isotopes to measure trophic positions of aquatic organisms across an environmental gradient. Author Keywords: agriculture, fish, food webs, nitrogen, stable isotopes, streams
Scientificity of Psychology and the Categorical Paradigm of Mental Illness
There is little research devoted to exploring psychology's historical and discursive development. Psychological knowledge is generally presented as the contributions of individuals, but without context. The social, political, and economic aspects of psychology's development are scarcely discussed, including how the discipline came to be considered a science. This thesis project explored the history of the development of psychology. Specifically, psychology's claim to scientificity via the appropriation of the medical model of disease, and accordingly, the instantiation of the categorical paradigm of mental illness were examined. The discontinuous events that shaped psychology and its hallmark of scientificity were explored, including extensive concept transformations, political agendas, and marketing strategies. These practices were then explored in a practical way using the conception of clinical depression and the role of antidepressants as the first-line treatment for depression in the USA. This exploration revealed psychology's socio-historical contingencies and its agenda of prediction and control. Author Keywords: Categorical Paradigm, Concept Transformations, Historicity, Knowledge Products, Psychology, Scientificity
Seasonal variation in nutrient and particulate inputs and outputs at an urban stormwater pond in Peterborough, Ontario
Stormwater ponds (SWPs) are a common feature in new urban developments where they are designed to minimize runoff peaks from impervious surfaces and retain particulate matter. As a consequence, SWPs can be efficient at retaining particle-bound nutrients, but may be less efficient at retaining nutrients that are present primarily in the dissolved form, like nitrogen (N). However, the forms of nutrients (e.g. particulate vs. dissolved) likely differ with hydrologic and seasonal conditions and few studies have examined year-round differences in nutrient forms and concentrations at urban SWPs. In order to contrast total suspended solids (TSS), phosphorus (P) and nitrogen (N) levels between low and high flow conditions, sampling was conducted at an urban SWP in Peterborough, ON between November 2012 and October 2013. Only an increase in TSS levels at the outflow between low and high flow conditions was observed, as well as a decrease in TSS levels at the outflow compared to Inflow 1 under low flow conditions. Nitrate-N (NO3-N) was the dominant form of N entering the pond under all flow conditions, whereas the fraction of total-P (TP) that was particulate increased under high flow conditions. Nevertheless, the dissolved fraction of TP was consistently high in these urban inlets. Only NO3-N was significantly greater in the inflows than outflow and only under low flow conditions. Increases in the proportions of organic-N and ammonium-N in the outlet suggest that biological processing is important for N retention. Author Keywords: nitrogen, Ontario, phosphorus, stormwater ponds, total suspended solids

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Graduate student theses produced at Trent University. You may also browse theses and dissertations by year, program, or author.

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1973 - 2033
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