McGill University Theses and dissertations by author name (I)

L'organisation de la chromatine est essentielle dans la régulation de l'expression des gènes chez les eucaryotes. Trypanosoma brucei échappe à la réponse des anticorps de l'hôte par variation antigénique, en changeant périodiquement la glycoprotéine de surface variable (VSG) exprimée. T. brucei possède environ 2 500 gènes et pseudogènes VSG ; cependant, ils n'expriment qu'un seul gène VSG à la fois à partir d'un site d'expression télomérique, alors que les gènes VSG restants sont subtélomériques et silencieux. Nous avons précédemment identifié un complexe protéique associé à la chromatine de 0,9 MDa impliqué dans l'inactivation du VSG via un système de régulation …  Read more

Purpose: Ocular toxoplasmosis is the most common etiology of posterior uveitis. The high incidence of macular scarring associated with ocular toxoplasmosis is a leading cause of visual morbidity. Serum biomarkers of the disease would aid in its diagnosis. This work was designed as a pilot study to detect potential biomarkers. Methods: Blood serum samples were collected from four groups of nine patients each; healthy, uveitic, one single-toxoplasmic event and recurrent events. Protein profiles were generated by SELDI-ToF-MS and 2-DE. Proteins were sequenced using tandem-MS. A tree-based decision classification system was developed. Results: 50 markers of ocular toxoplasmosis and 46 markers …  Read more

Beaver ponds are important parts of peatland landscapes and have high fluxes of CO2 and CH4. This study was undertaken in Mer Bleue Bog, Ontario, to determine the response of a beaver pond to drainage (lowering by 25 cm) as a sink or source of carbon. Plant distribution was changed in response to a new water table gradient. Each vegetation community and the remaining beaver pond were sampled for fluxes of CO2 and CH4 from mid-April to end-November, 1999, one year after the water table was lowered. A flow-through chamber system was used to measure CO2 flux from vegetated sites. …  Read more

The primary objective of this thesis is to explore the effect of omitting a strong prognostic factor from Cox's proportional hazards model when analyzing data from randomized trials. The secondary objective is to provide an overview of the Cox model. We first present the properties of the model, the method of maximum partial likelihood and the elements available on which to draw inferences concerning parameters. We then discuss various methods used to assess the tenability of the proportional hazards assumption as well as ways to incorporate non-proportional hazards in the model. In the third and final chapter, we address the …  Read more

Meta-analyses often consider the effect of a treatment on multiple, possibly related outcomes. Typically, summary estimates are derived from outcome-specific meta-analyses. Alternatively, a joint analysis can be conducted with a multivariate meta-analysis model, which also quantifies the correlation between the outcomes. This dissertation presents findings from analyses examining issues pertaining to the accuracy of the multivariate approach and its application to meta-analyses of longitudinal studies. Correlations measured in multivariate meta-analysis models can provide added insight about the treatment and disease. To be useful, however, the measured correlations must reflect the underlying biological relationships between treatment effects. I demonstrate, however, that …  Read more

The objective of this work was to examine the hydration performance of Portland cement with variations in their Tricalcium Silicate and Tricalcium Aluminate phases. The performance of Portland cement is affected by its particle size, chemistry, morphology, water availability, thermodynamic reaction rates, and age at which the materials are tested. The majority of research on Portland cement hydration has thus far evaluated each of its different components independently by examining how those phases react with water over time. However, Portland cement has many phases that are all reacting simultaneously depending on many different factors. How the different phases react while …  Read more

The exploration-exploitation trade-off is a fundamental challenge in reinforcement learning (RL), where an agent must balance exploiting known information to maximize immediate rewards and exploring the environment to discover potentially more rewarding strategies in the long run. While provably efficient algorithms exist for tabular and linear Markov Decision Processes (MDPs), they often struggle with scalability and applicability in complex settings. Conversely, heuristic-based deep RL exploration methods demonstrate strong empirical performance but lack theoretical guarantees, highlighting a significant gap between theory and practice.This thesis addresses this disparity by developing a unified framework for Thompson Sampling-based exploration strategies that combines theoretical rigor …  Read more

DNA is a remarkable material that is both an inspiration for polymer nanotechnology and a versatile building block for assembling well-defined nanostructures. To create polymeric materials that would be useful in nanotechnology, we synthesized block copolymers containing thymine and diamidopyridine side chains. These DNA-mimetic polymers self-assembled into spherical aggregates in solution, held together by hydrogen bonding interactions. We have reported the first example of a block copolymer micellar aggregate that is capable of selective recognition of small-molecule guests, with concomitant changes in its aggregation behavior. In the field of DNA-mediated materials, the ordering of gold nanoparticle (AuNP) arrays can be …  Read more

Rho GTPases are critical intracellular signaling molecules currently recognized for their ability to regulate cell morphology, migration, polarity, intracellular trafficking and gene expression. This class of proteins is implicated in development, cancer, genetic disorders, metabolism, and various biological contexts. Rho GTPase-activating proteins (RhoGAPs) represent a class of negative regulators of Rho GTPases. Cdc42 GTPase-Activating Protein (CdGAP/ARHGAP31) is a serine- and proline-rich RhoGAP with specific activity towards Cdc42 and Rac1. Currently, various functional domains of CdGAP have been characterized, and CdGAP mutations have been identified in patients with the Adams-Oliver Syndrome (AOS). In this thesis, we investigate in vivo roles of …  Read more

The i&barbelow;nterf&barbelow;eron&barbelow; (IFN) inducible d&barbelow;ouble s&barbelow;tranded (ds) RNA activated protein kinase PKR inhibits protein synthesis by phosphorylating the alpha-subunit of the eukaryotic translation initiation factor 2 (eIF-2alpha). The introduction of dominant negative mutants of PKR leads to cell transformation and tumor formation in nude mice, and is thought to be due to the deregulation of general protein synthesis. In addition to translational control, PKR has been implicated in several signaling pathways leading to gene transcription. For example, a link between PKR and NF-kappaB activation was first detected when PKR knockout mouse embryonic fibroblasts were deficient in NF-kappaB DNA binding upon …  Read more

This dissertation is concerned with experimental and analytical studies of the mechanics of interaction where a pneumatic tire is loaded vertically on a supporting ground, i.e., rigid base, clay and sand. The numerous experiments were conducted under various conditions to characterized the interactions in terms of the experimental results, e.g. axle displacement, contact area, contact pressure, etc. The results of pressure distribution indicate that recognizing a tire as a pneumatic body is crucial in establishing a rational theory for tire-supporting ground interaction problems. The pressure distribution and contact area obtained in the experiments are also utilized in validating an analytical …  Read more

Pseudomonas aeruginosa is an opportunistic pathogen that can cause a chronic lung infection in individuals with cystic fibrosis. The O antigen of lipopolysaccharide is a major virulence factor for Gram-negative bacteria and plays a critical role in bacterium-host interactions. The inhibition of O antigen biosynthesis is known to significantly reduce the virulence of P. aeruginosa. The O antigen biosynthetic enzymes are considered as promising novel targets to develop new antimicrobials to treat a P. aeruginosa infection. WbpP and WbpM are two UDP-GlcNAc-modifying enzymes that are involved in the initial steps of the O-antigen biosynthesis in P. aeruginosa serotype 06. WbpP …  Read more

Tropper, Carl (Supervisor1)  Read more

L'avortement à risque reste un défi majeur de santé publique au niveau mondial et contribue chaque année à un nombre effarant de décès et d'invalidités. L'accès à des services d'avortement sans risque est influencé par un large éventail de facteurs, dont l'environnement législatif. La loi sur l'avortement d'un pays est un élément clé pour déterminer l'environnement favorable à l'avortement sans risque. La plupart ont élargi les motifs pour lesquels l'avortement peut être pratiqué légalement, tandis que quelques-uns en ont restreint l'accès. On suppose que les réformes de la loi sur l'avortement influencent les services de santé génésique, maternelle et néonatale, …  Read more

Le dépistage du cancer du col de l’utérus par analyse de frottis cytologique ou test de Papanicolaou, communément appelé test Pap, a été introduit au Canada il y a de cela plusieurs décennies. Cette mesure a permis de réduire de façon considérable tant le taux d’incidence que le taux de mortalité de ce cancer. Ces taux se sont toutefois stabilisés au cours des dernières années; des gains importants reliés à ce type de dépistage sont donc peu probables. La faible sensibilité du test Pap de même que les coûts élevés des infrastructures et du personnel nécessaires au maintien de ce …  Read more

Dès l'âge de 4 ans, les enfants considèrent le mensonge comme étant un comportement immoral (Bussey, 1999). Cependant, très tôt, bien qu'ils développent une compréhension morale du mensonge et l'évaluent de façon négative, ils adoptent également un comportement de mensonge. Ils commencent à mentir afin de cacher leurs propres transgressions ainsi que pour couvrir les méfaits d'une autre personne (Talwar & Crossman, 2011). Des études antérieures sur les mensonges des enfants ont démontré que la compréhension morale et conceptuelle des mensonges ne permet pas de prédire le comportement réel des enfants en matière de mensonges (Talwar et al., 2002). Cette …  Read more

Lands, Larry (Supervisor2)  Read more

Experiments were carried out to examine the value of CCS (copper chaperone for CuZn superoxide dismutase) as a novel biomarker of zinc-induced mild copper deficiency and to evaluate the changes in expression of zinc transporters in response to graded levels of moderately high dietary zinc. Weanling male Wistar rats were fed graded levels of zinc (30, 60, 120 and 240 mg zinc/kg diet) for 5 weeks. Results showed a dose-dependent decrease in copper content and an increase in CCS expression in tissues of rats fed the Zn-60 and Zn-120 diets. Surprisingly, rats fed the Zn-240 diet showed better copper status …  Read more

Lorsque le Comité préparatoire pour l’indépendance de l’Indonésie (« BPUPKI ») s’est réuni pour rédiger la Constitution de 1945, ses membres ont reconnu leur manque d’expertise en matière constitutionnelle. Par conséquent, la constitution qu’ils ont produite a été caractérisée comme un documentélaboré à la hâte, considéré comme temporaire jusqu’à ce qu’un remplacement plus approprié puisse être conçu. Près de huit décennies plus tard, il est évident que la Constitution de 1945 est devenue la pierre angulaire du cadre constitutionnel durable de l’Indonésie, ne montrant aucun signe de remplacement imminent. Les chercheurs ont proposé diverses interprétations de ce phénomène, l’attribuant soit …  Read more

Attia, Mahmoud Helmi (Internal/Supervisor)  Read more

Hales, Barbara F. (Supervisor1)  Read more

Les compagnies pharmaceutiques dépensent des centaines de millions de dollars pour développer chaque médicament approuvé. Ce qui est moins connu, c’est l’investissement des patients dans ce processus en tant que participant dans des essais cliniques. Le but de cette thèse était d’explorer la relation entre les charges, les risques et les bénéfices pour les patients participant à des essais cliniques. Le chapitre 1 a abordé la question du temps que les patients atteints d'un cancer avancé consacrent aux essais de phase 1. Les essais de phase 1 représentent la plus faible probabilité de bénéfice pour les patients, mais le plus …  Read more

Incidental findings are findings discovered during medical testing, such as unexpected imaging results from an x-ray, and are unrelated to the primary purpose for which a test was sought. Some incidental findings have implications for patient autonomy and welfare. Incidental findings can involve risks as well as potential benefits. Incidental findings found in emergency departments are difficult to manage because of the fast-paced and crowded environment, as well as limitations to physician-patient relationships. This thesis explores policy and guideline documents, as well as literature, on the legal, professional, and ethical duties of emergency department healthcare professionals in identifying, disclosing, and …  Read more

Contexte: Le trouble dépressif majeur (TDM) et le trouble bipolaire (TB) sont des troubles de l'humeur qui sont associés aux coûts économiques à long terme et la détérioration fonctionnelle. L'impulsivité a été impliquée dans les troubles de l'humeur, principalement dans TB. L'impulsivité est associée à l'agression, le risque de comportement suicidaire, et la détérioration fonctionnelle globale chez les personnes avec un trouble de l'humeur. Des études ont montré que les individus avec le TB ont des niveaux d'impulsivité plus élevés que les témoins, bien que peu d'études aient examiné le lien spécifique entre l'impulsivité et TB contre TDM. En outre, …  Read more

Ma thèse explore l'impact des femmes révolutionnaires pendant la guerre de libération du Bangladesh en 1971 : elle examine les raisons qui ont poussé les femmes Bengalis à poursuivre l'activisme politique : pourquoi ont-elles pris les armes, ou ont fourni une protection aux révolutionnaires Bengalis dans leur lutte contre la junte militaire pakistanaise ? Le rôle des femmes révolutionnaires de la liberté dans l'histoire de la libération du Bangladesh est un thème peu étudié par rapport au rôle de leurs compatriotes masculins. Cette thèse vise à redonner aux femmes le pouvoir d'agir dans la lutte nationale pour la liberté. Méthodologiquement, …  Read more

Dufort, Daniel (Supervisor)  Read more

New teachers for new times?': a participatory evaluation of a school-university partnership to improve novice teacher education in rural South Africa in the age of AIDS is an evaluation of the Rural Teacher Education Project (RTEP), a school-university partnership between University of KwaZulu-Natal (UKZN) and two rural higher secondary schools in the Vulindlela district in the province of KwaZulu-Natal, South Africa. This thesis attempts to explore what difference the school-university partnership can make in preparing new teachers in the troubling context of rural schools typified by HIV and AIDS, poverty, and the sense of isolation. Drawing on the participatory evaluation …  Read more

Les techniques d'apprentissage profond ont permis d'améliorer les performances prédictives dans diverses tâches biomédicales, telles que le pronostic des maladies, le diagnostic et la prédiction de la survie. Bien que ces méthodes soient précieuses, il est souvent difficile de savoir ce que ces modèles apprennent réellement. L'intelligence artificielle explicable vise à fournir des informations sur les modèles d'apprentissage profond complexes, en fournissant des informations allant de l'importance des caractéristiques d'entrée jusqu'aux explications causales. Dans cette recherche, nous définissons dans un premier temps le concept de Goal-Oriented in SIlico Perturbations (GOSIP), une nouvelle approche qui génère des explications causales sur ce …  Read more

The seat of arbitration is undoubtedly important because of its supervision over the arbitration tribunal and the power to set aside the award. Most jurisdictions admit the territorial theory of international arbitration by adopting UNCITRAL Model Law. The delocalized theory of international arbitration is based on the doctrine of the enforcement of the annulled award. In fact, an annulled award does not exist and legally unenforceable. Bangladesh adopted the Model Law with an objective to become a center of international arbitration. It is evident that Bangladesh is yet to be considered an attractive place for international arbitration despite its adoption …  Read more

Ce mémoire porte sur la conception et la fabrication d’un laser à fibre ZBLAN dopée aux terres rares. La fibre possède une structure à double gaine avec grande ouverture numérique, ce qui permet de pomper efficacement la fibre de gainpar la gaine. Une étude détaillée de l’influence des paramètres du laser sur les caractéristiques du faisceau résultant est présentée, notamment la méthode de pompage, la longueur de fibre, et l’efficacité de couplage. Une analyse des facteurs déterminants dans la compétition entre les modes de la fibre est aussi présentée. De plus, l’effet du décalage en longueur d’onde sur la distribution …  Read more

Thermobaric effects on geostrophic (QG) turbulence is investigated numerically. In QG turbulence, theories of inverse energy cascades are based on conservation of energy and enstrophy. Thermobaric forcing breaks potential vorticity (PV) conservation and thus affects the classical picture of QG energy turbulence. In this thesis, we consider a modified version of QG (MQG) that takes into account thermobaric effects. We develop a numerical scheme for integrating this system and carry out simulations to examine how thermobaricity impacts the evolution of the flow. In a thermobaric fluid, lateral variability of the relative contributions of temperature and salinity in determining density affects …  Read more

Phagocytosis stimulates respiration, 'shunt' metabolism of glucose, lactic acid production and formate oxidation by the leucocytes. The stimulation of shunt metabolism of glucose during phagocytosis occurs only aerobically. Glycolytic inhibitors strongly inhibit phagocytosis. Cyanide and azide have no effect on the stimulated respiration and glucose oxidation, however, they completely inhibit the stimulated formate oxidation. Fatty acids with carbon chains from C6 to C15 inhibit phagocytosis.  Read more

Sulfonylureas have been an effective and inexpensive oral antihyperglycemic agent used in the management of type 2 diabetes for several decades. However, some studies have found that their use may be associated with an increased risk of cardiovascular death. A potential mechanism behind this risk is hypoglycemia-induced ventricular arrhythmia (VA). Several studies have explored the relationship between sulfonylureas and the risk of arrhythmic endpoints (including VA, cardiac arrest, and sudden cardiac death), but this literature has provided conflicting results regarding this potential adverse drug effect. Thus, my thesis had two primary objectives. The first was to synthesize the existing evidence …  Read more

This study was designed to derive a demand function for fresh potatoes in Canada. Several demand functions were estimated by the method of least squares for the period 1940 to 1965. The following one gave the best fit: <<equation in text>> As would have been expected, fresh potato proved to be a staple food with no good substitute in either bread or in vegetables. Contrary to the general belief fresh potato is not an inferior, good, let alone a Giffen good. The demand curve shifted downward by about 3 per cent per annum. The demand functions were also estimated separately …  Read more

Les plaies chroniques, caractérisées par un échec à progresser à travers les étapes normales de cicatrisation, représentent un défi majeur pour la santé, entraînant souvent des complications telles que les ulcère du pied diabétique (UPD) et les lésions de pression. Dans la maladie artérielle périphérique (MAP), le déploiement d'un stent provoque initialement une lésion vasculaire aiguë qui se transforme en une phase chronique, pouvant entraîner des complications comme la resténose intra-stent en raison d'une croissance néointimale excessive. En 2019, environ 113,4 millions de personnes âgées de 40 ans et plus vivaient avec une MAP, à l’échelle mondiale. La MAP, autrement …  Read more

Rationale: Idiopathic pulmonary fibrosis (IPF), a chronic and irreversible disease, is characterized by permanent scarring of the lung that results in death from respiratory failure. A key driver of this scarring is the accumulation of myofibroblasts, induced by transforming growth factor β (TGF-β), that produce excessive amounts of extracellular matrix (ECM) proteins. Recently, we showed that human antigen R (HuR) drives the differentiation of normal lung fibroblasts (NLFs) into myofibroblasts in response to TGF-β, concomitant with ECM protein production. HuR is an RNA-binding protein that controls numerous cellular functions, including differentiation, survival and proliferation. We hypothesized that the dysregulated function …  Read more

There are many factors affecting the decisions of students attending university. This research project specifically investigates the factors effecting the decisions made by second-generation South Asian Muslim women who grew up in Canada when attending higher education. Fifteen second-generation South Asian Muslim women were interviewed to understand their identity formation, and the factors that influence their attendance and participation in University education. Data suggest that their decisions are influenced by multiple factors, including but not limited to their family and societal expectations, and their personal goals and future empowerment.  Read more

L'objectif de cette thèse est de développer des agents d'IA qui apprennent à extraire une compréhension significative du monde, en étant capables de contrôler des aspects du monde qui peuvent être modifiés par l'agent, ou des informations qui affectent les actions de l'agent d'IA. L'hypothèse clé de ce travail est d'examiner quels aspects du monde un agent doit apprendre à travers des interactions avec le monde, de manière à pouvoir manipuler et développer une représentation contrôlable plus riche, mais simpliste, de son environnement. L'objectif central est de découvrir les états contrôlables pertinents, en prenant des mesures, de manière à gagner …  Read more

Yeats was part of a late nineteenth-century European literary movement which, dissatisfied with Western tradition, both scientific and religious, looked towards the Orient for enlightemnent. Unlike Pound, who sought solace in Japanese and Chinese sources, Yeats went to Indian philosophy and literature in his quest for "metaphors for poetry," and he remained a constant student of the Indian view of life. [...]  Read more

This study examines the nature of the state in Bangladesh and its role in the economic development of the country until President Ziaur Rahman's assassination in 1981. Two basic questions have been of central importance: who controlled the apparatus of the state? and was the state "relatively autonomous" or simply an instrument of the dominant class(es)? The study argues that the state in post-colonial Bangladesh has not, contrary to Hamza Alavi's position, followed a single uniform direction. Initially, nationalist political leaders, mostly belonging to the intermediate class, controlled the state apparatus, which can therefore be described as an "intermediate state." …  Read more

Speech coding algorithms have different dimensions of performance. Among them, speech quality and average bit rate are the most important performance aspects. The purpose of the research is to improve the speech quality within the constraint of a low bit rate. Most of the low bit rate speech coders employ linear predictive coding (LPC) that models the short-term spectral information as an all-pole filter. The filter coefficients are called linear predictive (LP) coefficients. The LP coefficients are obtained from standard linear prediction analysis, based on blocks of input samples. In transition segments, a large variation in energy and spectral characteristics …  Read more

The various forms and manifestations of international and transnational criminality require a comprehensive approach by the international community from which effective strategies of prevention, control, and suppression can follow. This thesis argues that the establishment of an ICC in the 1990s, especially due to the end of the Cold War and recent wars in the Persian Gulf and in Bosnia and Herzegovina, would provide an effective means of dealing with international and transnational criminality, and, without deflecting domestic concentration on law enforcement, would be a complementary and incremental effort, which would enhance overall criminal justice enforcement. This study analyzes past …  Read more

Cette recherche se concentre sur l'amélioration de l'usure à haute température par l'évaluation de quatre revêtements composites à matrice métallique de Stellite 6 produits par projection thermique HVOF (high-velocity oxygen-fuel) : 1) Un revêtement métallique sans carbure ; 2) Un revêtement composite contenant du Stellite 6 et du Cr3C2 ; 3) Un revêtement combinant du Stellite 6 et du WC-Ni ; et 4) Un revêtement contenant un mélange ternaire de poudres de Stellite 6, de carbure de tungstène (WC-Ni) et de carbure de chrome (Cr3C2).Des essais d'usure contre une bille d’alumine ont été réalisés à des températures allant de 25 …  Read more