Graduate Theses & Dissertations

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Modelling Depressive Symptoms in Emerging Adulthood
Depression during the transition into adulthood is a growing mental health concern, with overwhelming evidence linking the developmental risk for depressive symptoms with maternal depression. In addition, there is a lack of research on the protective role of socioemotional competencies in this context. This study examines independent and joint effects of maternal depression and trait emotional intelligence (TEI) on the longitudinal trajectory of depressive symptoms during emerging adulthood. A series of latent growth models was applied to three biennial cycles of data from a nationally representative sample (N=933) from the Canadian National Longitudinal Survey of Children and Youth. We assessed the trajectory of self-reported depressive symptoms from age 20 to 24 years, as well as whether it was moderated by maternal depression at age 10 to 11 and TEI at age 20, separately by gender. The results indicated that mean levels of depression declined during the emerging adulthood in females, but remained relatively stable in males. Maternal depressive symptoms significantly positively predicted depressive symptoms across the entire emerging adulthood in females, but only at age 20-21 for males. In addition, likelihood of developing depressive symptoms was attenuated by higher global TEI in both females and males, and additionally by higher interpersonal skills in males. Our findings suggest that interventions for depressive symptoms in emerging adulthood should consider development of socioemotional competencies. Author Keywords: Depression, Depressive Symptoms, Emerging Adulthood, Intergenerational Risk, Longitudinal, Trait Emotional Intelligence
MOVEMENT PARAMETERS AND SPACE USE FOR THE SOUTHERN HUDSON BAY POLAR BEAR SUBPOPULATION IN THE FACE OF A CHANGING CLIMATE
Changes to the Arctic and sub-Arctic climate are becoming increasingly evident as it warms faster than other areas of the globe, supporting evidence that predictions of future warming will be amplified due to positive feedback mechanisms. The Southern Hudson Bay polar bear (Ursus maritimus) subpopulation is one of the most southerly subpopulations in the world, putting it at increased risk due to effects of climate change. Whereas many other subpopulations have been the subject of intense research and monitoring, little research has been completed detailing the movement behaviour and space use of bears within Southern Hudson Bay. I used detailed movement data collected on female polar bears to establish a baseline of movement information for this subpopulation to which future work can be compared and effects of climate change can be assessed I evaluated the use of core areas during critical periods of the year (breeding and ice breakup) and evaluated common space use as a means of assessing site fidelity during the breeding season. Movement rates and home range sizes were comparable to those of the neighbouring Western Hudson Bay subpopulation. I also found evidence of increased occurrences of long distance, late fall movements along the coast to the northwest, presumably to gain earlier access to first ice. Though space use analysis did not reveal evidence of site fidelity to specific breeding areas in Hudson Bay, I found that core use areas are at risk of substantially shortened ice duration (x¯ =76 days shorter) using projected ice data based on the high emissions A2 climate change scenario. Author Keywords: climate change, Hudson Bay, movement, polar bear, sea ice, utilization distribution
CO2 dynamics of tundra ponds in the low-Arctic Northwest Territories, Canada
Extensive research has gone into measuring changes to the carbon storage capacity of Arctic terrestrial environments as well as large water bodies in order to determine a carbon budget for many regions across the Arctic. Inland Arctic waters such as small lakes and ponds are often excluded from these carbon budgets, however a handful of studies have demonstrated that they can often be significant sources of carbon to the atmosphere. This study investigated the CO2 cycling of tundra ponds in the Daring Lake area, Northwest Territories, Canada (64°52'N, 111°35'W), to determine the role ponds have in the local carbon cycle. Floating chambers, nondispersive infrared (NDIR) sensors and headspace samples were used to estimate carbon fluxes from four selected local ponds. Multiple environmental, chemical and meteorological parameters were also monitored for the duration of the study, which took place during the snow free season of 2013. Average CO2 emissions for the two-month growing season ranged from approximately -0.0035 g CO2-C m-2 d-1 to 0.12 g CO2-C m-2 d-1. The losses of CO2 from the water bodies in the Daring Lake area were approximately 2-7% of the CO2 uptake over vegetated terrestrial tundra during the same two-month period. Results from this study indicated that the production of CO2 in tundra ponds was positively influenced by both increases in air temperature, and the delivery of carbon from their catchments. The relationship found between temperature and carbon emissions suggests that warming Arctic temperatures have the potential to increase carbon emissions from ponds in the future. The findings in this study did not include ebullition gas emissions nor plant mediated transport, therefore these findings are likely underestimates of the total carbon emissions from water bodies in the Daring Lake area. This study emphasizes the need for more research on inland waters in order to improve our understanding of the total impact these waters may have on the Arctic's atmospheric CO2 concentrations now and in the future. Author Keywords: Arctic, Arctic Ponds, Carbon dioxide, Carbon Fluxes, Climate Change, NDIR sensor
Evaluating the effects of landscape structure on genetic differentiation and diversity
The structure and composition of the landscape can facilitate or impede gene flow, which can have important consequences because genetically isolated groups of individuals may be prone to inbreeding depression and possible extinction. My dissertation examines how landscape structure influences spatial patterns of genetic differentiation and diversity of American marten (Martes americana) and Canada lynx (Lynx canadensis) in Ontario, Canada, and provides methodological advances useful for landscape geneticists. First, I identified the effects of map boundaries on estimates of landscape resistance, and proposed a solution to the bias: a buffer around the map boundary. Second, I assessed the sensitivity of a network-based estimate of genetic distance, conditional genetic distance, to incomplete sampling. I then used these landscape genetic tools in a pairwise, distance-based analysis of 653 martens genotyped at 12 microsatellite loci. I evaluated whether forest management in Ontario has influenced the genetic structure of martens. Although forest management practices had some impact, isolation by distance best described marten gene flow. Our results suggest that managed forests in Ontario are well connected for marten and do not impede marten gene flow. Finally, I used a site-based analysis of 702 lynx genotyped at 14 microsatellite loci to investigate spatial patterns of genetic diversity and differentiation at the trailing (contracting) edge of the lynx distribution in Ontario. I analyzed harvest records and found that the southern edge of lynx range has contracted by >175 km since the 1970s. I also found that neutral genetic diversity decreased towards the trailing edge, whereas genetic differentiation increased. Furthermore, I found strong correlations between gradients of lynx genetic structure and gradients of climate and land cover in Ontario. My findings suggest that increases in winter air temperature, decreases in snow depth, and loss of suitable habitat will result in further loss of genetic diversity in peripheral populations of lynx. Consequently, the adaptive potential of lynx populations on the southern range periphery could decline. In conclusion, my dissertation demonstrates the varying influences that contemporary landscape structure and climate gradients can have on genetic diversity and differentiation of different species. Author Keywords: Circuitscape, genetic network, landscape genetics, Lynx canadensis, Martes americana, range shift
Archaeology of Vagabondage
My research examines the figure of the 'vagabond' as a case study to illustrate how 'modern' perception of the 'vagabond' has depleted the diversities in its 'pre-modern' counterparts. It argues that the paranoia towards the 'vagabond' was inherited from the west out of the colonial contact leading to the birth of the nation-state and its liaison with 'instrumental rationality' during the high noon of advanced industrial capitalism, while (quasi-religious) itinerancy, on the contrary, had always been tolerated in 'pre-modern' India. The problems I am addressing are: What is the line of thread that separates the 'traveler' from the 'vagabond', the 'explorer' from the 'wanderer'? How do we then politically account for the historic 'ruptures' in the vagabond having been tolerated in the ancient 'Indic' thought [cf. Manusmriti, Arthshastra], encouraged in early Buddhist discourse [cf. Samannaphala Sutta], revered as the 'holy Other' in the Middle Ages [cf. Bhakti-Sufi literature], and eventually marginalized in the 'modern'? While considering issues of cultural differences, my thesis points to how the epistemic shifts from the classical to the medieval, from the medieval to the modern radically alter the value system immanent in the figure of the 'vagabond'. The research argues that the cultural baggage that the expression 'vagabond' is generally associated with, is a product of a specific western/utilitarian value system, which is a distinct 'cultural' category of the 'modern' west that had no resonance in 'pre- modern' India, and hence cannot be necessarily universalizable. The project works in a number of registers: historical, archival, cultural, philosophical and representational, involves analysis of literary, filmic texts, also legislative documents, and is genuinely interdisciplinary in nature. As of discourse analysis, the project studies the politics of cultural representations both of and by 'vagabonds'. Author Keywords: 1943 Bengal Famine, Homelessness, India, Vagabond, Vagrancy, Vagrancy Act
Soil mineralizable nitrogen as an indicator of soil nitrogen supply for grain corn in southwestern Ontario
Soil mineralizable nitrogen (N) is the main component of soil N supply in humid temperate regions and should be considered in N fertilizer recommendations. The objectives of this study were to determine the potentially mineralizable N parameters, and improve N fertilizer recommendations by evaluating a suite of soil N tests in southwestern Ontario. The study was conducted over the 2013 and 2014 growing seasons using 19 field sites across southwestern Ontario. The average potentially mineralizable N (N0) and readily mineralizable N (Pool I) were 147 mg kg-1 and 42 mg kg-1, respectively. Pool I was the only soil N test that successfully predicted RY in 2013. The PPNT and water soluble N (WSN) concentration (0-30cm depth) at planting were the best predictors of fertilizer N requirement when combing data from 2013 and 2014. When soils were categorized based on soil texture, the relationships also improved. Our findings suggest that N fertilizer recommendations for grain corn can be improved, however, further field validations are required. Author Keywords: corn, nitrogen, nitrogen mineralization, soil nitrogen supply, soil N test, southwestern Ontario
effects of parasitism on consumer-driven nutrient recycling
Daphnia are keystone consumers in many pelagic ecosystems because of their central role in nutrient cycling. Daphnia are also frequently infected, and the parasites causing these infections may rival their hosts in their ability to regulate ecosystem processes. Therefore, parasitic exploitation of Daphnia may alter nutrient cycling in pelagic systems. This thesis integrates existing knowledge regarding the exploitation of Daphnia magna by 2 endoparasites to predict parasite-induced changes in the nutrient cycling of infected hosts and ecosystems. In chapter 1, I I contextualizing the integration of these themes by reviewing the development of the fields of elemental stoichiometry and parasitology. In chapter 2, we show how the bacterial parasite, Pasteuria ramosa, increased the nitrogen (N) and phosphorus (P) release rates of D. magna fed P-poor diets. We used a mass-balance nutrient release model to show that parasite-induced changes in host nutrient accumulation rates and diet-specific changes in host ingestion rates were responsible for the accelerated nutrient release rates that we observed. In chapter 3, we extended our examination of the nutrient mass balance of infected D. magna to include another parasite, the microsporidian H. tvaerminnensis. We found differences in the effects of these two parasites on host nutrient use as well as support for the hypothesis that parasite-induced changes in Daphnia N release are caused by the effects of infection on Daphnia fecundity. In chapter 4, we examined the relationship between P concentrations and the presence and prevalence of H. tvaerminnensis in rock pools along the Baltic Sea. We found that particulate P concentrations were negatively associated with the prevalence of this parasite, a result that is consistent with the increase in P sequestration of H. tvaerminnensis-infected Daphnia that we observed in chapter 3. I discuss the potential implications of the work presented in chapters 2-4 for other parasite-host systems and ecosystems in chapter 5. Overall, the research presented here suggests that parasite-induced changes in host nutrient use may affect the availability of nutrients in the surrounding environment, and the magnitude of this effect may be linked to parasite-induced reductions in fecundity for many invertebrate hosts. Author Keywords: consumer, ingestion rates, mass-balance, nutrient-recycling, parasitism, phosphorus
Lipid-derived Thermoplastic Poly(ester urethane)s
Thermoplastic poly(ester urethane)s (TPEU)s derived from vegetable oils possess inferior physical properties compared to their entirely petroleum-based counterparts due to the structural limitations and lower reactivity of the precursor lipid-derived monomers. The present work shows that high molecular weight of TPEUs with enhanced performance can be obtained from lipid-derived monomers via (i) the synthesis of polyester diols with controlled molecular weights, (ii) the tuning of the functional group stoichiometry of the polyester diols and the diisocyanate during polymerization, (iii) the degree of polymerization (iv) the control of the hard segment hydrogen bond density and distribution via the use of a chain extender and (v) different polymerization protocols. Solvent-resistant TPEUs with high molecular weight displaying polyethylene-like behavior and controlled polyester and urethane segment phase separation were obtained. Structure-property investigations revealed that the thermal transition temperatures and tensile properties increased and eventually plateaued with increasing molecular weight. Novel segmented TPEUs possessed high phase separation and showed elastomeric properties such as low modulus and high elongation analogous to rubber. The response of the structurally optimized TPEUs to environmental degradation was also established by subjecting the TPEUs to hydrothermal ageing. TPEUs exhibited thermal and mechanical properties that were comparable to commercially available entirely petroleum-based counterparts, and that could be tuned in order to achieve enhanced physical properties and controlled degradability. Author Keywords: Hydrothermal degradation, Molecular weight control, Polyester diols, Renewable resources, Structure-property relationships, Thermoplastic poly(ester urethane)s
Anarchist Periodical Press in the United States
This dissertation focuses on the English-language anarchist periodical press in the United States in the 1890s and early 1900s. Each of the three chapters of this dissertation examines one anarchist paper and its coverage of a specific issue. The first chapter focuses on Prison Blossoms, which was started by Alexander Berkman, Carl Nold, and Henry Bauer and written and circulated in the Western Penitentiary of Pennsylvania, and its engagement with Alexander Berkman's attempt to assassinate Henry Clay Frick. The second chapter examines Free Society, a weekly edited primarily by Abraham Isaak, and its contributors' writings on the assassination of President William McKinley by self-described anarchist Leon Czolgosz. Finally, the third chapter focuses on The Demonstrator, specifically its first volume which was edited by James F. Morton Jr. from the intentional community of Home, Washington, and the paper's work in supporting John Turner, the first anarchist targeted for deportation under the Immigration Act of 1903. Drawing upon critical discourse analysis, this dissertation incorporates examination of the context in which these papers were written (particularly the immediate concerns to which the papers' authors responded), the form and generic conventions of the anarchist press, including the approaches of the papers' respective editors, and the arguments advanced by their authors. It pays particular attention to the intertextuality of the anarchist press -- the ways in which those writing in anarchist papers addressed one another both within and across periodicals, generating anarchist thought through conversation and debate and enacting their anarchist ideals in the practice of publishing. This dissertation demonstrates that the anarchist periodical press, an element of anarchist history that has received little attention, offers important insights: it details how anarchists immediately responded to important issues of their time, and reveals the ways in which the emergence of anarchism was itself a collective effort, emerging from conversation, debate, and disagreement about how best to create radical change and what that change should look like. Author Keywords: anarchism, anarchist periodicals, critical discourse analysis, Free Society, Prison Blossoms, The Demonstrator
Social thermoregulation and potential for heterothermy
Northern and southern flying squirrels (Glaucomys sabrinus and G. volans, respectively) are experiencing a climate change induced increase in range overlap, resulting in recent hybridization. We investigated the occurrence of heterospecific communal nesting, a potential facilitator of hybridization, and aimed to confirm the presence of torpor, a potential barrier to hybridization, in flying squirrels. In wild-caught captive squirrels, we conducted a paired nest choice experiment and found that heterospecific nesting did occur, but in a lower frequency than conspecific nesting. Ambient temperature did not affect the frequency of grouped nesting. We attempted to induce torpor in flying squirrels in a laboratory through cold exposure while measuring metabolic rate and body temperature. Strong evidence of torpor was not observed, and metabolic rate remained unchanged with season. We conclude that torpor is not a barrier to hybridization in flying squirrels, but resistance to heterospecific nesting may indicate the existence of one. Author Keywords: heterospecific group, hybridization, northern flying squirrel, social thermoregulation, southern flying squirrel, torpor
Modeling drought derivatives in arid regions
We propose a stochastic weather model based on temperature, precipitation, humidity and wind speed for Qatar, as a representative arid region, in order to obtain simulated values for a drought index. As a drought index, the Reconnaissance Drought Index (RDI) is commonly accepted in agriculture and is used to measure drought severity. It can be used to price weather derivatives to help farmers reduce nancial losses from drought. RDI, which is the ratio of precipitation to evapotranspiration, is calculated by considering crop growth stages. The use of dierent crop coecient value depending on the growth stage to calculate evapotranspiration can provide improved values for RDI. Additionally, six calculation methods for evapotranspiration using weather data are investigated to obtain accurate values for RDI. Author Keywords: Evapotranspiration, Markov chains, Mean reversion processes, Reconnaissance Drought Index, Stochastic dierential equations, Stochastic weather models
Pedagogy of Renaturalization
This three-part dissertation will consider both theoretical and practical implications that Baruch Spinoza's (1632-1677) immanent philosophical system holds for developing a contemporary “pedagogy of renaturalization.” One of the intents of this thesis is to draw out how “intellectual slut shaming” is a naturalized part of neoliberal subjectivity. In chapter one, we will make the case that the Cartesian and neoliberal subjects share several parallel structures, including mind-body dualism. We will look at how Spinoza’s work supplies us with a powerful critique and expansion of the Cartesian subject. The intent here is to explore how we might apply a similar critique to the neoliberal subject and construct a more joyful subject that resists guilt, shame, and self-hatred. In chapter two, we will explore how Spinoza’s method of affirmation can give us a process to engage ourselves in a pedagogy of renaturalizing ourselves; in other words, to engage in the radical self-reflexivity of understanding ourselves as a part of Spinoza's Nature in order to better affect becomings of ethical joy. We will also examine the challenges and criticism of the affirmative method, and how paradoxically these criticisms serve to reinforce intellectual slut shaming. Chapter three will explore the potential of the methodology of autoethnography and the development of what we are calling “auto-ethology” as a way to put such an affirmative method into practice. By reviewing the dissertation as a whole, we will show how it has been an engagement with Spinozist radical self-reflexivity all along and a performance of auto-ethology. Author Keywords: autoethnography, Baruch Spinoza, Cartesian dualism, critical pedagogy, intellectual slut shaming, neoliberal subject

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Format: 2022/08/19