Graduate Theses & Dissertations

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Evidence of an Interaction Between Memory Stores for Long-Term Context Fear Memory in the Rat
Memories which typically require the hippocampus (HPC) can become represented in structures outside of the HPC, and therefore resistant to HPC damage, but, the properties of these memories are poorly understood. Some research has suggested that the HPC continually contributes to memories that are resistant to hippocampal damage, and without this support, they are weaker and more susceptible to loss. However, this hypothesis has yet to be tested experimentally. We examined this possibility in rats by assessing decay and extinction of a context fear memory that had become independent of the HPC via repeated learning episodes. We found that HPC-independent context fear memories decay and extinguish faster without continued HPC support, suggesting that the HPC plays a continued role in long-term memory. We also provide new evidence of a persistent interaction between the HPC and other memory systems, which strengthens non-HPC representations so that they withstand HPC damage at longer intervals. Author Keywords: consolidation, context fear, hippocampus, memory, retrograde amnesia
Drink my beer, smoke my weed, my good friends are all I need
Past research has predominately supported an association between insecure attachment and substance use. More recent research has found that while individuals with secure attachment may use substances, they do so with less risk. The current study attempted to replicate the finding regarding secure attachment and substance use and examined the motivational drives behind why students use substances. A total of 318 undergraduate students completed self-report questionnaires examining peer attachment, alcohol and marijuana use, as well as motivations for use. Results indicated that students who reported low frequency use of alcohol or marijuana did not have significantly higher security ratings compared to students who reported increased use. Additionally, although hypothesized, secure attachment ratings were not associated with social facilitation or enhancement motivations. However, fearful and dismissing attachment ratings were both significantly associated with coping motives as predicted, while preoccupied and fearful attachment ratings were significantly associated with conformity motives. Lastly, results from multiple regressions suggest that coping and enhancement motivations are significant predictors of alcohol use, while enhancement motivations are marginally significant in predicting marijuana use. Author Keywords: alcohol, attachment, marijuana, motivation
Surface temperature regulation during stress exposure
The influence of stress exposure on the body temperature of vertebrates has been known for nearly two-thousand years. While the proximate mechanisms supporting this phenomenon are well described, the ultimate mechanisms remain enigmatic. In this thesis, I propose a novel hypothesis which states that changes in body surface temperature (henceforth "surface temperature") following stress exposure occur to reduce energetic expenditure toward thermoregulation, thus freeing energy for use in the stress response (hereafter, the "Thermoprotective Hypothesis"). Using a paired experimental design, I first show that black-capped chickadees (Poecile atricapillus, Linnaeus, 1766) exposed to repeated stressors decrease their surface temperatures at low ambient temperatures, and increase their surface temperatures at high ambient temperatures relative to unstressed controls. These changes in surface temperature contribute to a relative reduction in heat loss in the cold, and a relative increase in heat dissipation in the warmth among stress-exposed individuals, thus reducing their energetic demands toward more costly thermoregulatory strategies. Next, I show that stress-induced changes in surface temperature are most pronounced in chickadees that experience naturally-occurring resource-restrictions, suggesting that this response occurs to balance allocation of energy among the stress response and thermoregulation (i.e. a true energetic trade-off ). Third, I show that the magnitudes of chronic, stress-induced changes in surface temperature are highly variable among, and highly consistent within, chickadees, therefore suggesting that this response could hold adaptive significance if such variation among individuals is heritable. Finally, using domestic pigeons (Columba livia domestica, Gmelin, 1789) as a model species, I show that stress-induced changes in surface temperature are highly pronounced at bare tissues with a critical role in thermoregulation for some avian species (the bill), when compared with responses at surrounding bare tissues (the eye region). Together, these findings strongly support the Thermoprotective Hypothesis and suggest that endotherms may trade energetic investment toward thermoregulation with that toward the stress response in resource-limiting environments. Author Keywords: heat transfer, infrared thermography, stress physiology, surface temperature, thermoregulation, trade-off
An Emergent Model of the Return to Learn Process for Adolescents with Prolonged Concussion
Current literature on concussion management focuses primarily on the return to physical activity, while the return to learn process is less clearly understood. This knowledge gap is particularly problematic for adolescents, whose primary responsibility is academics. The present study sought to develop a more in-depth understanding of the return to learn process through the perspectives of adolescents who had sustained a concussion and their parents in in-person, semi-structured interviews. A substantive grounded theory of the return to learn process for adolescents that emerged from the data is provided. The basic model is consistent with many speculative, non-empirically based concussion management protocols, but extends these models by emphasizing the central role of parents in managing their child’s recovery process, highlighting the importance of role fulfillment within the concussion management network, and identifying the impact of the adolescent’s capacity and readiness for help-seeking. The results also highlight the vulnerability of concussed adolescents to losing their support structure as they move through key school transitions. Implications for educators, medical professionals, parents, and adolescents in the return to learn process are also discussed. Author Keywords: Adolescent, Concussion, Concussion Management, Multidisciplinary Management, Return to Learn, Return to School
Anthropogenic microfibres in background natural environments in Ireland
Microfibres, which are threadlike particles < 5 mm, are the most common type of microplastic reported in the environment. However, few studies have focused on their abundance in background natural environments. This study assessed the abundance of microfibres in rainfall samples (from four precipitation monitoring stations) and across three headwater lake catchments that were in remote, undeveloped areas, away from anthropogenic disturbance and anthropogenic emission sources (i.e., sites were background natural environments). Anthropogenic microfibres were observed in all samples using visual identification methods, with Raman spectroscopy confirming the presence of polyester film and synthetic pigments, e.g., indigo and hostasol green. The estimated annual average atmospheric deposition of microfibres was ~28,800 mf m-2. Meteorological variables, e.g., rain, wind direction, and relative humidity were correlated with the abundance of microfibres. The average abundance of microfibres in headwater lake catchments was 24 mf g-1 in moss, 0.70 mf m-3 in surface trawl, 9,690 mf m-3 in subsurface, 910 mf kg-1 in lake sediment and 576 mf kg-1 in lakeshore sediment. Author Keywords: Atmospheric Deposition, Background Environments, Headwater Lake Catchments, Microfibres, Microplastics, Rainfall
methodological framework for the assessment and monitoring of forest degradation under the REDD+ programme based on remote sensing techniques and field data
In this thesis, a methodological framework for the assessment and monitoring of forest degradation based on remote sensing techniques and field data, as part of the REDD+ programme, is presented. The framework intends to support the implementation of a national Monitoring, Verification and Report (MRV) system in developing countries. The framework proposed an operational definition of forest degradation and a set of indicators, namely Canopy Cover (CC), Aboveground Biomass (AGB) and Net Primary Productivity (NPP), derived from remote sensing data. The applicability of the framework is tested in a sub-deciduous tropical forest in the Southeast of Mexico. The results from the application of the methodological framework showed that the higher rates of forest degradation, 1596-2865 ha·year-1, occur in areas with high population density. Estimations of aboveground biomass in these degraded areas span from 1 to 24 Mg·ha-1, with a rate of carbon fixation ranging from 130 to 246 gC·m2·year. The results also showed that 43 % of the forests of the study area remain with no evident signs of degradation, as detected by the indicators selected, during the period evaluated. The integration of the different elements conforming the methodological framework for the assessment and monitoring of forest degradation enabled the identification of areas that maintain a stable condition and areas that change over the period evaluated. The methodology outlined in this thesis also allows for the identification of the temporal and spatial distributions of forest degradation based on the indicators selected, and it is expected to serve as the basis for operations of the REDD+ programme with the appropriate adaptations to the area in turn. Author Keywords: Forest degradation, Monitoring, REDD+, Remote Sensing, Tropical forest
Managing Through Change
Arctic ecosystems are increasingly altered by climate change, and some wildlife species, like moose, are adapting to these new conditions. Indigenous knowledge and values, such as those held by Inuit, can provide insight into adaptive wildlife management and may improve ecosystem resiliency. This thesis seeks to address the following question: What is the potential role of Indigenous knowledge in managing wildlife under climate change? This thesis follows a qualitative exploratory design involving 1) a systematic literature review of the peer-reviewed literature and 2) a case study on moose in Nunatsiavut in which 35 interviews and participatory mapping were conducted with Inuit beneficiaries. The results demonstrate a range of potential roles for Indigenous knowledge and values in managing species impacted by climate change. The case study of moose in Nunatsiavut has applicability across the Canadian Arctic where the sustainability of harvested species is at risk. Author Keywords: Arctic, climate change, Indigenous knowledge, moose, Nunatsiavut, wildlife management
Solving Differential and Integro-Differential Boundary Value Problems using a Numerical Sinc-Collocation Method Based on Derivative Interpolation
In this thesis, a new sinc-collocation method based upon derivative interpolation is developed for solving linear and nonlinear boundary value problems involving differential as well as integro-differential equations. The sinc-collocation method is chosen for its ease of implementation, exponential convergence of error, and ability to handle to singularities in the BVP. We present a unique method of treating boundary conditions and introduce the concept of the stretch factor into the conformal mappings of domains. The result is a method that achieves great accuracy while reducing computational cost. In most cases, the results from the method greatly exceed the published results of comparable methods in both accuracy and efficiency. The method is tested on the Blasius problem, the Lane-Emden problem and generalised to cover Fredholm-Volterra integro-differential problems. The results show that the sinc-collocation method with derivative interpolation is a viable and preferable method for solving nonlinear BVPs. Author Keywords: Blasius, Boundary Value Problem, Exponential convergence, Integro-differential, Nonlinear, Sinc
Lacanian Realism
The overarching argument of this manuscript concerns Lacanian Realism, that is, the Lacanian theory of the Real. Initially, my argument may seem quite modest: I claim that Lacanians have been preoccupied with a particular modality of the Real, one that insists on interrupting, limiting, or exceeding the various orders or agencies of the human mind. The implications of such a position are worth considering. For example, one must, as a consequence of holding this position, bracket questions pertaining to Things outside of the Symbolic and Imaginary psychical systems. Careful study shall expose the extent to which this position has infuenced each of the major felds inspired by Jacques Lacan: clinical psychoanalysis, radical political philosophy, and mathematics or topology. My task has been to explore the consequent occlusion which psychoanalysis has suffered in each of these three felds and to tease out the possibility of a return to the Real. Author Keywords: Alain Badiou, Anarchism, Hysteria, Jacques Lacan, psychoanalysis, Slavoj Zizek
Ostrich Eggshell from the Far Eastern Steppe
This study uses stable isotope analysis on both the organic and inorganic fractions of ostrich eggshell obtained from archaeological excavations in Mongolia, northern China, and southern Siberia. By establishing the δ13Corg, δ15N, δ13Cinorg, δ18O isotopic compositions of the eggshell of the Asian ostrich (Struthio asiaticus), this study provides insight into the maximum northern range of the species, which I suggest reached Lake Baikal, Siberia through the late Pleistocene, up to the Last Glacial Maximum. Through these isotopic data, the interactions between S. asiaticus and human forager groups are explored, specifically the trade of ostrich eggshell by hunter/gatherer populations in the early/middle Holocene. Because of deviations from the correlation between δ18O and latitude observed for other sites, the site of Shabarakh-usu may have been an aggregation point for ostrich eggshell from other locations. Movement of eggshell is observable from north to south but not from south to north on the basis of eggshell δ18O. Finally, I am able to develop a hypothesis regarding the drivers of species extinction. Specifically, I discuss trade in eggshell leading up to extinction as evidence for human pressure on S. asiaticus at a time when environmental shifts likely isolated populations in small regions of habitable landscape. I therefore implicate both changing environmental conditions and human pressure in my proposed explanation for the extinction of S. asiaticus. Author Keywords: Extinction, Holocene, ostrich, Pleistocene, Steppe, Struthio
An Ethical Analysis of Bell's Targeted Ad Prorgram
Online behavioural advertising (OBA) is an advertising technique which relies on collected customer information and online activity to serve people with more relevant ads. On November 16th, 2013, Bell Canada launched their first OBA program via Bell Mobility: the Bell Targeted Ads Program, or BTAP. My thesis provides an ethical analysis of BTAP and shows that Bell undermined and violated customer privacy, stifled customer autonomy, and harmed customer identity. Relevant moral problems include typification, a disrespecting of customer autonomy, and identity commodification. I show that BTAP was unethical by grounding my arguments within the moral framework of Information Ethics (IE). IE is an ethical system which focuses on the role of information in the ethical dilemmas. IE also justifies the self-constitutive theory of privacy (SCP) which argues that our information and privacy are entangled with our identities. This gives us strong reason to defend our privacy/identity within BTAP. After making several arguments which demonstrate that BTAP was unethical, I will then turn my attention to showing how it is possible to rectify and mitigate many of BTAP’s ethical problems by installing a two-stage opt-in (TSOI) which provides customers with a greater deal of autonomy, and the ability to remove themselves from BTAP. Author Keywords: Bell Canada, Ethics, Identity, Online Behavioural Advertising, Privacy, Targeted Advertising
Stop Making Sense
ABSTRACT There is a growing number of juvenile novels and picture books that mean to educate the reader about synaesthesia. The synaesthete in these texts for young readers desires to be a social agent, yet sh/e also considers synaesthesia to be a healing power and a deeply personal psychedelic form of escapism; I argue that the synaesthete in these texts `uses' their synaesthesia to dissipate emotional trauma caused by pubescent uncertainty and social isolation. In this thesis, I propose that YA and Children's texts that feature synaesthesia generally reinforce the discursive constraints of normative perception, and they also promulgate the assumption that synaesthesia is an extraordinary form of cognition instead of a legitimate subject position. Author Keywords: Authenticity, Liminality, Repesentation, Synaesthesia, Synesthesia, Zizek

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Format: 2024/02/22