University of Lethbridge Theses
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- ItemTowards new zwitterioinic difluoroglycine analogues: preparation methods and reactivity studies(Lethbridge, Alta. : University of Lethbridge, Dept. of Chemistry and Biochemistry, 2025) Lilienthal, Elaura O.; University of Lethbridge. Faculty of Arts and Science; Hamel, Jean-DenysResearch into new methods of fluorination is imperative as the addition of fluorine onto organic molecules has a great influence on a compound’s properties. Difluorocarbene can be used in such fluorination methods, and it is currently being explored for its unique properties. The purpose of this thesis was to see if it was possible to create new zwitterionic difluoroglycine-derived difluorocarbene precursors, and to test their ability against the previously reported phosphine-based analogue. The formation of the phosphine-based difluorocarbene source is achieved through nucleophilic substitution, and then release of the difluorocarbene through heating. It was believed that this procedure can be ameliorated, by improving the atom economy of the reaction, as well lowering the temperature of release allowing for better use on small scale and in industry. First, the precursors would have the phosphine group swapped for new nitrogen and sulfur-based groups, hopefully allowing for difluorocarbene release at a lower temperature. This was tested by using different types of amines, pyridines and two sulfides. A subset of potential difluorocarbene precursors was thus synthesized. The new difluorocarbene sources were tested in (2+1) cycloaddition reactions and difluoromethylation reactions to test their ability to release the difluorocarbene. The nitrogen-based precursors were tested against the phosphine analogue and showed comparable results. However, all data collected proved that the concept of forming these new difluoroglycine analogues and their reactivity bears potential, but is not fully understood yet. The work presented in this thesis gives key insights into the possibility of synthesizing zwitterionic difluoroglycine analogues and their subsequent reactivity.
- ItemForm-preserving transformations of the Schrödinger equation(Lethbridge, Alta. : University of Lethbridge, Dept. of Physics and Astronomy, 2025) Daub, Mason J.; University of Lethbridge. Faculty of Arts and Science; Walton, Mark A.Coordinate transformations of differential equations have long been studied in the context of mathematics and physics. They allow us to change a differential equation into one that is easier to solve. In nonrelativistic quantum mechanics, the time evolution of a wave function is determined by the time-dependent Schrodinger equation (TDSE). Since quantum mechanics must work in every nonrelativistic frame, there must be a TDSE for every set of coordinates one chooses to measure in. Coordinate transformations between two reference frames must then transform one Schrodinger equation into another. Called form-preserving transformations (FPTs), these transformations allow for many puzzling solutions to the TDSE and can be used for the efficient determination of symmetry groups. In this work, we will determine the most general allowed FPT for the Schrodinger-Pauli equation of a spinless charged particle in N-dimensions. Furthermore, we show that the FPTs form a continuous Lie group, whose algebra is discussed in detail. Well-known symmetry groups such as the Galilean and Schrodinger groups are shown to be subgroups of the form-preserving group. We conclude with an analysis of FPTs in the phase-space formulation of quantum mechanics.
- ItemRbm-od: a restricted Boltzmann machine framework for outlier detection(Lethbridge, Alta. : University of Lethbridge, Dept. of Mathematics and Computer Science, 2025) Hoeksema, Brady F.; University of Lethbridge. Faculty of Arts and Science; Zhang, John Z.This thesis explores the use of Restricted Boltzmann Machines (RBMs), a class of unsupervised generative neural networks, for detecting outliers through data generation and representation-based comparison. Outlier detection (OD) is a critical task in domains where rare or anomalous patterns may indicate errors, fraud, or unexpected behaviour in data. The primary contribution of this work is a unified framework for RBM-based outlier detection that emphasizes data generation as a detection strategy. We explore multiple model variants, including single RBMs, ensembles of RBMs, stacked RBMs, and ensembles of stacked RBMs, each offering distinct advantages in representing complex data patterns. By generating synthetic samples from trained RBMs and comparing them to input data, the approach enables unsupervised detection of unusual or unexpected instances. This gener ative perspective distinguishes RBM-OD from traditional methods and provides a flexible foundation for future extensions.
- ItemAdvanced boundary-enhanced instance segmentation and spatial-temporal transformer models for automated schizophrenic investigation(Lethbridge, Alta. : University of Lethbridge, Dept. of Mathematics and Computer Science, 2025) Imarhiagbe, Osasumwen Raphael; University of Lethbridge. Faculty of Arts and Science; Zhang, John Z.Accurate segmentation and detection in neuroimaging is essential for advancing clinical understanding and the diagnosis of schizophrenia. This thesis introduces Boundary-Refined Attention Network (BoRefAttnNet), a novel boundary-refined 3D U-Net variant specifically designed for precise segmentation of subcortical brain structures from structural magnetic resonance imaging (sMRI). BoRefAttnNet incorporates multi-scale boundary attention modules that explicitly highlight anatomically critical edges while suppressing background noise, significantly improving segmentation accuracy for small or complex anatomical structures. Evaluations using FastSurfer-processed sMRI data from the publicly available Centre for Biomedical Research Excellence (COBRE) dataset demonstrate that BoRefAttnNet significantly outperforms conventional 3D U-Net baselines in accurately delineating key subcortical structures, including the hippocampus, amygdala, and basal ganglia. Building upon this enhanced segmentation capability, we further experiment with a Dynamic Spatial-Temporal Transformer Model (DySTTM) to detect schizophrenia by integrating structural and functional MRI (fMRI) modalities. The DySTTM leverages spatial attention to capture anatomical interdependencies from segmented sMRI data and temporal attention to model dynamic brain connectivity patterns from resting-state fMRI. Experimental results indicate that the integration of these multimodal imaging features using DySTTM provides superior diagnostic accuracy and interpretability compared to established models such as 3D ResNet and XGBoost classifiers.
- ItemTransformational leadership and positive development: assessing the cascade effect in university sport(Lethbridge, Alta. : University of Lethbridge, Dept. of Kinesiology and Physical Education, 2025) Hawkins, Olivia J.; University of Lethbridge. Faculty of Arts and Science; Rathwell, ScottThe Full-Range Leadership Model (FRLM) stipulates that transformational leadership is effective because the behaviours of the leaders cascade down throughout the organization, creating more transformational leaders. However, this phenomenon has yet to be studied within the sport context. The purpose of this study was to examine the influence of the cascade effect on the relationship between coaches’ transformational leadership and university student-athletes’ (SAs) positive development (PD) over time. Using a longitudinal design, 30 athletes (20 female, Mage = 20.47) from various U SPORTS teams completed surveys at three points during their season assessing their coaches' transformational leadership behaviors (DTLI), the transformational qualities of their teammates, and their own PD outcomes (USES). Correlational analyses were used to test whether a) the number of transformational team leaders relates to changes in athletes PD, b) coaches’ TFL behaviours are related to changes in PD, and c) coaches’ TFL behaviours are related to changes in the number of transformational team leaders. Results indicated that higher levels of coaches’ transformational leadership were associated with reductions in negative sport-related experiences such as negative peer interactions and inappropriate adult behavior. Furthermore, teams with a greater density of transformational peer leaders reported stronger development in areas such as initiative, basic skills, and social capital. Evidence of a cascade effect—whereby transformational coaches influenced the emergence of transformational team leaders—was found primarily between the start and midpoint of the season. However, mediation analyses did not support the cascade effect as a mechanism linking coach leadership to PD outcomes. These findings offer novel insight into how transformational leadership functions within university sport and provide practical implications for leadership development among student-athletes.