Graduate Theses & Dissertations

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"Multimodal Contrast" from the Multivariate Analysis of Hyperspectral CARS Images
The typical contrast mechanism employed in multimodal CARS microscopy involves the use of other nonlinear imaging modalities such as two-photon excitation fluorescence (TPEF) microscopy and second harmonic generation (SHG) microscopy to produce a molecule-specific pseudocolor image. In this work, I explore the use of unsupervised multivariate statistical analysis tools such as Principal Component Analysis (PCA) and Vertex Component Analysis (VCA) to provide better contrast using the hyperspectral CARS data alone. Using simulated CARS images, I investigate the effects of the quadratic dependence of CARS signal on concentration on the pixel clustering and classification and I find that a normalization step is necessary to improve pixel color assignment. Using an atherosclerotic rabbit aorta test image, I show that the VCA algorithm provides pseudocolor contrast that is comparable to multimodal imaging, thus showing that much of the information gleaned from a multimodal approach can be sufficiently extracted from the CARS hyperspectral stack itself. Author Keywords: Coherent Anti-Stokes Raman Scattering Microscopy, Hyperspectral Imaging, Multimodal Imaging, Multivariate Analysis, Principal Component Analysis, Vertex Component Analysis
ADAPT
This thesis focuses on the design of a modelling framework consisting of loose-coupling of a sequence of spatial and process models and procedures necessary to predict future flood events for the years 2030 and 2050 in Tabasco Mexico. Temperature and precipitation data from the Hadley Centers Coupled Model (HadCM3), for those future years were downscaled using the Statistical Downscaling Model (SDSM4.2.9). These data were then used along with a variety of digital spatial data and models (current land use, soil characteristics, surface elevation and rivers) to parameterize the Soil Water Assessment Tool (SWAT) model and predict flows. Flow data were then input into the Hydrological Engineering Centers-River Analysis System (HEC-RAS) model. This model mapped the areas that are expected to be flooded based on the predicted flow values. Results from this modelling sequence generate images of flood extents, which are then ported to an online tool (ADAPT) for display. The results of this thesis indicate that with current prediction of climate change the city of Villahermosa, Tabasco, Mexico, and the surrounding area will experience a substantial amount of flooding. Therefore there is a need for adaptation planning to begin immediately. Author Keywords: Adaptation Planning, Climate Change, Extreme Weather Events, Flood Planning, Simulation Modelling
ADHD Symptomatology Across Adulthood
Objective: To improve on several methodological issues and research gaps regarding current literature investigating the stability of ADHD symptomatology across adulthood and relationships between the two core ADHD symptom dimensions (i.e., inattention and hyperactivity-impulsivity) and multiple life outcomes in adults. Method: A large sample of postsecondary students were initially assessed for ADHD symptomatology using the Conners’ Adult ADHD Rating Scale (CAARS). Six years later, academic success was assessed using students’ official academic records (e.g., final GPAs and degree completion status), and fifteen years later, participants were re-assessed using the CAARS and several measures of life success (e.g., relationship satisfaction, career satisfaction, and stress levels). Results: Inattention and hyperactivity-impulsivity symptoms showed strong stability across the 15-year period. Additionally, greater inattention symptoms during emerging adulthood and early middle adulthood were consistently associated with poorer life success (e.g., lower GPAs, poorer relationship and career satisfaction), particularly for men. Associations for hyperactivity-impulsivity symptoms were less consistent. Conclusion: ADHD symptomatology can be conceptualized as a stable, dimensional trait across adulthood, with robust associations with measures of life success. Author Keywords: academic success, ADHD, adults, job satisfaction, relationship satisfaction, stability
Academic Efficiency
Universities produce a significant and increasing share of basic research that is later commercialized by firms. We argue that the university's prominence as a producer of basic research is the result of a differential efficiency in research production that cannot be replicated by firms or individual agents - teaching. By using research accomplishments to signal knowledge and attract tuition-paying students, universities are uniquely positioned to undertake certain types of research projects. However, in a market for innovation without patent rights, a significant and increasing number of basic research projects, that are social welfare improving, cannot be initiated by firms or universities. The extension of patent rights to university-generated research elegantly redresses this issue and leaves us to ponder important questions about the future of our innovation-driven economies. Author Keywords: Innovation, Intellectual Property Rights, Research, Science Technology and Innovation Policy
Academic Procrastination, Self-Regulation, Anxiety and Personality (ASAP)
Academic procrastination is analogous to a common cold: pervasive and with no established cure. Students experience repercussions that are not inclusive to academic performance, but rather, are experienced across mental, physical, social and emotional domains as well. While this necessitates treatment, much of the behaviour has yet to be explained. In the current study, a state approach was integrated to explore procrastination in terms of the Yerkes-Dodson paradigm. Procrastination was hypothesized to arise for one of two reasons: students are either too low or too high in anxiety. A sample of 847 Ontario undergraduate students completed measures of procrastination, state-anxiety, personality, and self-regulation. Results suggest 88% of students procrastinate regularly, and contrary to what was hypothesized, procrastination and anxiety were linearly related. Independent t-tests establish that relative to non-procrastinators, procrastinators are significantly more emotionally and biologically dysregulated and less socially integrated. Factor analysis demonstrated three central reasons contributing to procrastination, which were used as the basis to establish types of procrastination: social (n=61), self-doubt (n=70) and low-energy (n=76) procrastinators. Results indicate divergences across procrastination type with respect to personality as well as biological, affective and social domains. Findings also inform that the expression of procrastination, varies across student. Overall, findings suggest that academic interventions should acknowledge and address the variability among procrastinators. Author Keywords: ACADEMIC PROCRASTINATION, ANXIETY, PERSONALITY, SELF-REGULATION
Adoption of a Finite Element Model of Material Deformation Relevant to Studying Corneal Biomechanics
The human cornea is required to exhibit specific material properties to maintain its regular shape under typical intraocular pressures which then allow for its correct optical functionality. In this thesis, the basis of continuum solid mechanics and the finite element method are introduced. We use finite element modelling to simulate the extension of an effective-1d, linear-elastic bar, a cornea-like body governed by Poisson’s equation, and the deformation of a loaded, linear-elastic, cube. Preliminary results for the deformation of a simulated, linear-elastic, cornea have also been achieved using the finite element approach. Author Keywords: continuum solid mechanics, corneal biomechanics, finite element method, intraocular pressure
Agricultural Intensification at Cerro de Oro (Cañete Valley, Peru)
Stable carbon and nitrogen isotope analysis of 571 archaeobotanical samples was performed to assess agricultural practices at Cerro de Oro in the Cañete Valley, Peru, during the transition between the Early Intermediate Period and the Middle Horizon. This thesis presents a comprehensive range of δ13C and δ15N values for the major C3 and C4 plant resources at the site. No differences were found in the δ15N values of charred and desiccated maize cobs, suggesting that both types of plant remains can provide reliable δ15N measurements. Generally, the δ15N values of plants at the site were relatively high, with the exception of most of the legumes, suggesting that organic fertilizers were extensively used. Camelid dung and fish offal are the most likely fertilizers used at Cerro de Oro, but some very high δ15N values suggest that seabird guano may also have been used. Peanuts, a legume, had higher δ15N values than would be expected for legumes, suggesting that this plant may have been companion-planted alongside maize or other more heavily fertilizer crops. Cotton had the highest δ13C value among all of the C3 plants sampled from the site, suggesting that this crop grew in the driest conditions, possibly reflecting a deficit irrigation system. This study reveals how intensive and extensive agriculture supported the emergence and growth of Cerro de Oro, a monumental site of great regional importance. Author Keywords: Andean Archaeology, Carbon and Nitrogen Stable Isotope Analysis, Cerro de Oro, Early Intermediate Period and Middle Horizon, Intensive and Extensive Agriculture, Plants
Agro-Ecological Zoning (AEZ) of Southern Ontario and the Projected Shifts Caused by Climate Change in the Long-term Future
This thesis proposes an agro-ecological zoning (AEZ) methodology of southern Ontario for the characterization and mapping of agro-ecological zones during the historical term (1981-2010), and their shifts into the long-term (2041-2070) projected climate period. Agro-ecological zones are homogenous areas with a unique combination of climate, soil, and landscape features that are important for crop growth. Future climate variables were derived from Earth System Models (EMSs) using a high emission climate forcing scenario from the Intergovernmental Panel on Climate Change 5th Assessment Report. The spatiotemporal shifts in agro-ecological zones with projected climate change are analyzed using the changes to the length of growing period (LGP) and crop heat units (CHU), and their manifestation in agro-climatic zones (ACZ). There are significant increases to the LGP and CHU into the long-term future. Two historical ACZs exist in the long-term future, and have decreased in area and shifted northward from their historical locations. Author Keywords: Agro-climatic Zones, Agro-ecological Zones, Agro-ecological Zoning, Climate Change, Crop Heat Units, Length of Growing Period
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
An Application of the Sinc-Collocation Method in Oceanography
In this thesis, we explore the application of the Sinc-Collocation method to an oceanography model. The model of interest describes a wind-driven current with depth-dependent eddy viscosity and is formulated in two different systems; a complex-velocity system and a real-value coupled system. In general, the Sinc-based methods excel over other traditional numerical methods due to their exponentially decaying errors, rapid convergence and handling problems in the presence of singularities at end-points. In addition, the Sinc-Collocation approach that we utilize exploits first derivative interpolation, whose integration is less sensitive to numerical errors. We present several model problems to demonstrate the accuracy, and stability of the method. We compare the approximate solutions determined by the Sinc-Collocation technique with exact solutions and also with those obtained by the Sinc-Galerkin approach in earlier studies. Our findings indicate that the method we utilized outperforms those used in past studies. Author Keywords: Boundary Value Problems, Eddy Viscosity, Oceanography, Sinc Numerical Methods, Wind-Driven Currents
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
An Exploration of Attachment Influences on Rape Attitudes
While there is substantial research on the influence of adverse childhood experiences on sexual offending behaviours and attachment representations on sexual offending behaviours, few studies to date have explored how adverse childhood experiences and attachment representations act together to influence the development of rape attitudes in a non-clinical population. The purpose of this thesis was to explore how childhood experiences and attachment may help to understand the development of rape attitudes. Data were collected from 273 undergraduate students who completed self-report questionnaires pertaining to their attachment, childhood experiences and rape attitudes. Correlational and Structural Equation analyses were computed, and the results did not find support for the simultaneous influence of adverse childhood experiences and attachment representations on rape attitudes. Given that the sample was primarily female (83%), the results indicate that the outcomes of adverse childhood experiences on sexual attitudes may differ by gender. Understanding the formation of rape attitudes is important to understand the motivations behind sexual assault behaviours. Author Keywords: adverse childhood experiences, rape attitudes

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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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