University of Lethbridge Theses
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- ItemEvaluating the role of memory in a rodent model of epilepsy(Lethbridge, Alta. : University of Lethbridge, Dept. of Neuroscience, 2023) Das, Ritwik; University of Lethbridge. Faculty of Arts and Science; Luczak, ArturEpileptogenesis is a complex and not well understood phenomenon. It has been largely described as pathology occurring because of an imbalance between excitatory and inhibitory brain networks. Through our experiments we attempted to show that epileptogenesis could be “hijacking” the brain mechanisms responsible for memory formation. We began by using an associative experimental design, pairing auditory and visual cues with electrically kindled evoked seizures to design a rodent model of reflex seizures. Reflex seizures are a clinical phenomenon characterized by convulsive episodes induced by specific sensory stimuli or cognitive actions. Our experiment failed to establish a reflex seizure model in rodents, but interestingly we observed behavior and electrophysiology similar to fear conditioning, with significant freezing in animals paired with cues. Using the same animals, we investigated memory reconsolidation blocking therapies, which rely upon replaying neuronal activity but instead of strengthening, involved synapses are weakened. We used rapamycin to weaken neuronal circuitry replayed with the sensory cues and evoked seizures to weaken epileptic networks. Although this was aimed as an exploratory study, the drug therapy abolished seizures in two animals, demonstrating promising results.
- ItemThe Lansing effect in Lemna turionifera (Lemnoideae) and potential contributing factors(Lethbridge, Alta. : University of Lethbridge, Dept. of Biological Sciences, 2023) Dutt, Priyanka; University of Lethbridge. Faculty of Arts and Science; Laird, Robert A.The Lansing effect is a specific type of parental age effect whereby older parents have shorter-lived offspring than younger parents. The phenomenon is important because it implies the presence of non-genetic forms of inheritance relating to parental age, such as epigenetics or physiological effects. Further, the existence of the Lansing effect informs our understanding of the evolution of life histories because it shows that senescence – traditionally defined in terms of decreases in survival and reproduction with age – also involves a decrease in offspring quality. The Lansing effect has been observed in a wide variety of taxa, including plants. Here, I investigated the Lansing effect in the subfamily Lemnoideae (duckweeds). My objectives were two-fold: (1) testing for the Lansing effect, and (2) if the Lansing effect is present, determining whether shortened lifespans of offspring of older parents are due to a higher mortality rate at all ages (i.e. a difference in baseline mortality), or a faster-accelerating mortality with age. I recorded lifespan, reproduction, and other metrics of fitness of 392 individuals; half were their parent’s first clonal offspring (offspring of younger parents), and half were fifth clonal offspring (offspring of older parents). Offspring of older parents had shorter lifespans (i.e., the Lansing effect occurred) and produced fewer offspring themselves compared to offspring of younger parents. Further, a model-selection approach indicated that offspring of older parents had a greater initial mortality rate at birth that then persisted through life compared to offspring of younger parents. Thus, greater baseline mortality was responsible for the Lansing effect for the plants in this experiment. My work emphasizes that senescence can manifest in offspring as a result of parental age effects, specifically the Lansing effect, in addition to the more well described phenomena of decreasing survival and reproduction.
- ItemNondual metaphysics: connections between Shankara's Advaita Vedanta and the thought of René Guénon(Lethbridge, Alta. : University of Lethbridge, Dept of Religious Studies, 2023) Freihaut, Forrest D.; University of Lethbridge. Faculty of Arts and Science; Rodrigues, HillaryThis thesis analyzes the metaphysical interpretations of Shankara and René Guénon and the methods they promote regarding spiritual realization. Shankara was an 8th-century Indian spiritual teacher whose method and teachings were associated with Advaita Vedanta, a philosophic tradition originating from Upanishadic texts. René Guénon (1886 -1951) was a French philosopher who pioneered the Traditionalist school of thought. Guénon’s interpretation of reality argued an all-pervading unitive metaphysic principle that shares notable similarities with Shankara’s Advaita Vedanta. Through comparative exegesis, this thesis demonstrates that Shankara and Guénon share significant parallels in certain aspects, such as their conceptualization of ultimate reality and their views on the role of the guru. Additionally, this analysis reveals stark contrasts found among their works, such as their differing emphasis on theory and their views on initiation and lineage. In addition to analyzing their interpretations of reality, this study offers insights into Shankara and Guénon’s respective lives and unique positions in history. The intention of this thesis is to contribute to a deeper understanding of the similarities and differences between Shankara and René Guénon and provide valuable insights into their approaches to spiritual realization and how they conceptualize reality.
- ItemRobust maximum covering location problem (RMCLP)(Lethbridge, Alta. : University of Lethbridge, Dept. of Mathematics and Computer Science, 2023) Jafaripour, Saeid; University of Lethbridge. Faculty of Arts and Science; Benkoczi, RobertThe Maximum Covering Location Problem (MCLP) is a widely recognized optimization problem used in facility location planning. The objective of this problem is to minimize costs while maximizing accessibility to customers. In this thesis, the MCLP is being solved as an optimization problem under uncertain customer benefits in a network, to minimize regret, which is the difference between the cost of the optimal solution under the worst- case scenario and the cost of the current solution under the worst-case scenario. Three algorithms were implemented to solve the problem and find the optimal solution, including an exact algorithm and two approximate algorithms. The algorithms were evalu- ated using various instances, including the OR-Library and randomly generated instances. The results indicate that the exact algorithm is better at minimizing regret, but it is unable to solve large instances within the allotted time limit. Also, one of the approximate algo- rithms based on a Mean-Scenario, which is a 2-Approximation general algorithm, indicates very competitive results to obtain the Min-Max Regret. The observations of this thesis confirm the results of related research for both the exact algorithm and the Mean-Scenario algorithm, which rely on standard and general methodologies. Also, the solutions obtained by the other approximate algorithm based on randomized rounding are within only nine percent of the Mean-Scenrio algorithm results, which proves the value of this approach.
- ItemA quantum accelerated approach for the central path method in linear programming(Lethbridge, Alta. : University of Lethbridge, Dept. of Mathematics and Computer Science, 2023) Adoni, Vijay; University of Lethbridge. Faculty of Arts and Science; Gaur, DayaThe central path method is a crucial technique used in the optimization of linear programs. The method relies on classical computation which hits its limit for large instances, generally used in practice, in terms of efficiency. In this thesis, a proposal is made to explore the use of quantum algorithms to enhance the central path method’s performance when solving linear programs. We will go through the potential benefits and limitations of replacing the iterative equation-solving step with the HHL quantum algorithm, the Newton’s step for solving a set of nonlinear equations, and converting the nonlinear set of equations to bilinear equations with the help of McCormick relaxations. The aim of this thesis is to perform extensive experimentation on several types of efficient instances using each of the proposed algorithms and to evaluate their effectiveness through numerical simulations to find a promising approach for the central path method.