McGill University Thèses et mémoires par auteur commençant par Y

Overhead transmission conductors are vulnerable to fretting fatigue caused by aeolian vibrations. Accurately estimating the residual lifespan of in-service lines under aeolian vibration is crucial for making informed decisions regarding their inspection, repair, or replacement. This study develops a three-step methodology using data from a 450 m undamped span equipped with an Aluminum Conductor Steel Reinforced (ACSR) conductor on a test line in Quebec, Canada. The first step of the methodology is the characterization of the exposure of an electric transmission line to the wind at a non-instrumented location. The wind speed and direction distribution are estimated by interpolating regional …  Read more

Part consolidation (PC) is an effective design technique to reduce part count and simplify product architecture. Through PC, it brings numerous benefits such as reduced assembly operation, decreased supply chain management cost, and increased structural reliability. Consolidation of parts, however, may lead to increased manufacturing difficulty in terms of complex geometry and material composition. Constrained by the capability of conventional manufacturing methods (e.g. machining and casting), PC is only applicable to components having simple geometries, no relative motion, no material variance, and no blockage of assembly access of others. As additive manufacturing (AM) evolves into an end-of-use product fabricating method, …  Read more

Kollman, Justin (Internal/Supervisor)  Read more

Les cils cellulaires sont des organites à base de microtubules qui s'étendent de presque toutes les cellules eucaryotes. Les cils sont les principaux acteurs de nombreuses fonctions cellulaires, telles que la motilité, la transduction du signal et le développement embryonnaire. La construction et le maintien des cils sont réalisés par de nombreuses protéines travaillant ensemble dans le transport intraflagellaire (IFT). Au cours de l'IFT, les tubulines, la pierre angulaire des cils, sont transportées dans le cil pour construire des microtubules doublets. Un grand sous-complexe tel que le complexe du bras de dynéine externe axonémal (ODA) est pré-emballé dans le cytoplasme …  Read more

Le système de tutelle pour adultes est un mécanisme juridique efficace qui permet de venir en aide aux adultes ayant perdu leurs facultés à faire de bons jugements ou à prendre des décisions de leur propre chef. Bien que la Chine ait entrepris depuis les années 2010 des réformes quant aux lois régissant le système de tutelle pour adultes, il existe encore quelques lacunes ou imperfections, et un régime systématique n'a pas encore été mis en place. En revanche au Canada, le système de tutelle pour adultes est passé d'un modèle inadéquat à un modèle très amélioré par l'établissement du …  Read more

The objectives of this project are (1) to reduce the excursions between real heater temperatures and the desired values, and (2) to realize cyclic production of plastic sheets on the AAA thermoforming machine. At first, present relevant knowledge and modeling of the AAA machine are covered. A programmable pre-processing module is inserted before the heaters to prevent the input commands from delaying in heater response. The results prove that the excursions can be theoretically reduced to zero. Based on the Terminal Iterative Learning Control (TILC) algorithm, a hybrid dual-mode cascade-loop system is designed: the inner loop monitors the real-time temperatures …  Read more

The Eocene-Oligocene boundary marked the transition from a very warm to a much cooler global climate, and the first appearance of large ice sheets in Antarctica. The opening of the Drake Passage and hence the establishment of the Antarctic Circumpolar Current (ACC) has been proposed as a mechanism for the dramatic Southern Hemisphere cooling at this time. Previous modelling studies explicitly addressing the impact of the Drake Passage used models with simple representations of an atmosphere, and did not consider the Panamanian Seaway, which was open at the time, allowing Atlantic and Pacific waters to exchange. Here, a coupled, fully-dynamic …  Read more

In order to utilize biomass as an alternative fuel, biomass pelletization and the fundamental combustion behavior of biomass pellets were studied. The physical and chemical characteristics of biomass powder were also investigated. The pelletization of biomass powder was optimized in order to obtain strong pellets, which can be easily injected to a reactor and burn efficiently without slagging and fouling. Biomass pellets were subjected to a slow heating process using a Thermogravimetric Furnace (TGF) coupled with a Fourier-Transform Infrared Spectrometer (FTIR). The mechanism of biomass pellets during combustion and the evolution of combustion gases from the solid residues were identified. …  Read more

Duggavathi, Raj (Supervisor1)  Read more

Cette thèse explore une approche de soins de santé durables et équitables en exploitant des cliniques mobiles alimentées par l'IA, adaptées aux communautés mal desservies et éloignées. Dans les régions où une forte pénétration des téléphones mobiles contraste fortement avec une connectivité Internet limitée, ce travail introduit des solutions pour fournir des diagnostics et des services médicaux hors ligne sur des appareils aux ressources limitées.S'appuyant sur la prominence croissante de l'intelligence artificielle (IA), y compris l'apprentissage profond (DL) et l'apprentissage automatique (ML), en médecine, cette recherche reconnaît que, bien que les ingénieurs soient à l'origine de nombreuses innovations technologiques, les …  Read more

En réponse à l'escalade des exigences de trafic, le modèle innovant Centralized Edge Twin (ET) propose un changement significatif par rapport aux systèmes traditionnels de gestion du trafic. Cette recherche explore la capacité de l'ET à prendre des décisions de conduite coopérative en temps réel et à exercer une supervision avancée du trafic depuis une perspective externe. En développant une architecture de données basée sur des graphes spécialement conçue pour notre plateforme de planification, nous avons élargi la portée du modèle ET pour englober une variété de scénarios de trafic, y compris les autoroutes et les intersections non signalisées. En …  Read more

Une part importante de la population mondiale n’a pas accès aux services de santé essentiels, en particulier dans les régions éloignées et mal desservies, où les systèmes de santé traditionnels sont souvent limités par une infrastructure insuffisante et des coûts élevés pour les patients. Ce mémoire examine comment l’intelligence artificielle (IA) peut contribuer à réduire ces inégalités et soutenir l’Objectif de Développement Durable 3 des Nations Unies, visant une couverture santé universelle, en rendant les services médicaux plus intelligents, évolutifs et accessibles. Deux méthodes innovantes sont explorées : In-Context Evolutionary Search (ICE-SEARCH), un cadre basé sur les modèles de langage …  Read more

Le développement des aéronefs à décollage et atterrissage verticaux électriques (eVTOL) s’impose comme une solution de nouvelle génération pour répondre à la demande croissante en mobilité aérienne avancée. Parmi les configurations envisagées, l’eVTOL à aile basculante (tiltwing) se distingue par sa capacité à décoller et atterrir comme un hélicoptère tout en volant comme un avion à voilure fixe, combinant ainsi la manœuvrabilité du VTOL et l’efficacité aérodynamique du vol horizontal. Cependant, la transition entre le vol vertical et horizontal demeure un défi majeur en raison des changements complexes du champ d’écoulement. Dans cette étude, des modèles semi-aile rectangulaires basés sur …  Read more

An in vitro system containing a rabb1t serum medium adapted subline of L5178Y cells and rabbit antiserum was used to study the effects of antibodies, in the absence of complement, on cells in culture. Heat-inactivated antiserum inhibits cell growth and colony formation in soft agar, and kills the cells. These actions occur slowly and metabolic events, in sequence; that is, RNA synthesis is inhibited after 4 hr, but the effects on the rates of protein and DNA syntheses become demonstrable only after 6 to 8, and 8 hr, respectively. Maximal inhibition can he obtained after 24 to 48 hr. These …  Read more

Wet cell electron microscopy is important for a wide range of studies from biological theory to polymer physics and chemistry. Wet cell microscopy is typically performed using silicon nitride (SiN) cells which have a fundamental limit to their resolution. This is due to limitations in how thin the SiN membranes can be etched. With the discovery of graphene in 2004, we are able to surpass these limitations by replacing SiN membranes with an atomic thick layer of graphene. This thesis will highlight the fabrication and results obtained in our novel graphene wet cell device. In particular, we are able to …  Read more

Partout dans le monde, les étudiants internationaux constituent une part de plus en plus importante de la population étudiante dans les établissements d'enseignement supérieur. Parmi eux, les étudiants internationaux chinois représentent un pourcentage important et significatif. Pourtant, malgré l'augmentation du nombre d'inscriptions, les institutions d'accueil manquent encore de compréhension des besoins de ces étudiants et des grands défis auxquels ils sont confrontés lors de leur transfert dans un nouvel environnement universitaire. Cette étude a pris une perspective narrative pour étudier les défis que rencontrent les étudiants internationaux diplômés chinois pendant leurs études dans une université canadienne de renommée mondiale. Grâce …  Read more

Le nématode Caenorhabditis elegans est un organisme modèle qui a été extensivement étudié afin de mieux comprendre les bases de la génétique du vieillissement. Ces études ont mené à l'identification de plusieurs gènes jouant des rôles essentiels dans la détermination de la durée de vie de ce ver rond. La majorité de ces gènes sont exprimés au niveau des mitochondries, des organelles reconnues pour jouer un rôle primordial dans la régulation du métabolisme énergétique et pour être les principales sources des dérivés actifs de l'oxygène (reactive oxygen species, ROS). Ces deux caractéristiques propres aux mitochondries sont reconnues pour être cruciales …  Read more

Economic exploitation of mineral resources, especially in underdeveloped mountainous areas, requires evaluating potential base-metal deposits over a large area of mineralization. Sophisticated techniques of potential field data processing are needed for this purpose, including reliable methods for regional-residual separation, continuation of potential fields and accurate computation of magnetic field in various rock materials. For the regional-residual separation problem, it is shown that the finite element method can be useful in conjunction with the generalized linear inverse approach, to produce improved regional and residual gravity maps compared to traditional methods. Then the generalized linear inverse method is applied to downward continuation …  Read more

This dissertation explores how sexual and gender minorities (SGMs) interpret, experience, and make decisions about marriage, cohabitation, and family in Canada’s post-marriage equality context. Drawing on census, survey, and interview data across three chapters, I engage with theoretical debates regarding the implications of marriage equality for LGBTQ+ people’s household dynamics and cultural beliefs. Specifically, I investigate differences in intrahousehold specialization across institutional contexts among same-sex couples (SSCs) and different-sex couples (DSCs); how traditionalist beliefs are distributed along the lines of gender, sexuality, and marital status; and how cultural assimilation occurs on the ground among LGBTQ+ people in the wake of …  Read more

Flotation is a complex, interactive system influenced by chemical, operational, and machine-related factors. Changing any variable in one of these three factors can affect the overall flotation performance. In this study, two sets of experiments were designed to study the effect of frother and their blends in flotation practice: air/water system in the lab (at McGill Minerals Processing Group) and air/water/solids system in two plants (a zinc-lead mine in China and a coal mine in Mongolia).In the two-phase lab tests, one variable in each factor, i.e., temperature as the operational factor, superficial gas velocity (air rate) as the machine factor …  Read more

Human mitochondrial NAD-dependent methylenetetrahydrofolate dehydrogenase-methenyltetrahydrofolate cyclohydrolase was expressed in a soluble and active form in Escherichia coli, purified to homogeneity for the first time and characterized. Phosphate is absolutely required for the dehydrogenase activity. NADP can be utilized by the dehydrogenase with a low turnover rate. The properties of the enzyme suggest that it has evolved from NADP to NAD specificity by the unique mechanism of substituting inorganic phosphate for the 2$ sp prime$-phosphate of NADP. The role of Mg$ sp{++}$ in this process is not understood, but it is required for activity with both dinucleotides. This enzyme is proposed …  Read more

Chang, Xiao-Wen (Internal/Supervisor)  Read more

Contexte: Les biphényls polychlorés (BPC) sont des polluants organiques persistants qui nuisent à la santé humaine par le biais de l'exposition alimentaire. Les BPC altèrent l'intégrité de la barrière intestinale et augmentent l'inflammation dans les cultures cellulaires et les modèles animaux. La perturbation inflammatoire de l'épithélium intestinal par les BPC pourrait être un mécanisme par lequel l'exposition alimentaire aux BPC pourrait jouer un rôle causal dans les maladies chroniques inflammatoires, comme l'indiquent les études épidémiologiques. Les BPC peuvent induire une inflammation intestinale par l'intermédiaire de l'induction de l'activité de la NAD(P)H oxydase (NOX), comme le suggère une étude sur la …  Read more

The aim of the study was to investigate the mechanisms of bronchoconstriction induced by dry gas hyperpnea challenge in the rat. The interaction of airway hyperresponsiveness to contractile agonists and the atopic constitution of the animals with responsiveness to hyperpnea challenge was also evaluated. A hyperresponsive strain, Fisher 344, two control normoresponsive strains, Lewis and ACI, and an atopic but normoresponsive rat, Brown Norway (BN) to dry gas hyperpnea challenge were studied. The effects of the NK1 (CP-99994), the NK2 (SR-48968) receptor antagonists, and the selective LTD4 receptor antagonist pranlukast on responses to hyperpnea challenge were examined in BN rats. …  Read more

Vladimir Khanassov (Supervisor2)  Read more

The overall objective of this research was to investigate the feasibility of using artificial neural networks to detect the incidence of clinical bovine mastitis and to determine the major factors influencing it. The first part of this research was devoted to a general examination of the learning ability of artificial neural networks by training them with relatively small data sets. These data sets (a total of 460,474 records) contained suspected indicators of mastitis such as milk production, stage of lactation and somatic cell count, and it was hoped that artificial neural networks would be able to detect what statistical modelling …  Read more

Le hockey sur glace, ou tout simplement appelé « le hockey » en Amérique du nord, est considéré comme le sport national d’hiver au Canada. Le développement de la vision numérique, l’émergence des appareils informatiques de pointe et l’avancement des équipements de divertissements personnels ont rendu l’analyse sportive un domaine de recherche particulièrement populaire. La clé pour comprendre et analyser un match de hockey de manière automatisée est de localiser le « protagoniste » du jeu, plus précisément, la rondelle. Pour cela, dans ce projet, nous cherchons à résoudre le problème du suivi de la rondelle dans les vidéos diffusées …  Read more

The met proto-oncogene receptor tyrosine kinase has been identified as the receptor for hepatocyte growth factor (HGF)/scatter factor (SF). HGF/SF is a multifunctional cytokine that is expressed predominantly by mesenchymal cells and stimulates mitogenesis, motogenesis, morphogenesis of a broad spectrum of epithelial and endothelial cells in culture. To elucidate the normal physiological role for the met receptor (R) in the adult mouse, I first determined the cell-type specific expression of the met R in adult mouse tissues by in situ hybridization. I have demonstrated that the met R is generally expressed in epithelial cells of many tissues, as well as …  Read more

Kleinman, Claudia (Supervisor1)  Read more

The effect of the time of application of Gibberellic Acid (GA3) and Lipo-Chitin Oligosaccharides (LCOs) on annual production of globe artichoke (Cynara scolymus L.) cultivars 'Imperial Star' and 'Green Globe' was studied in 2000 and 2001. In order for flowering to occur plants must undergo a period of vernalization. In 2000, plants received 54 chilling (vernalizing) hours, an amount sufficient to induce flowering in 100% of the Imperial star and 25% of the Green Globe control plants. Applications of 25ppm GA3 at the 6 and 10-leaf stage reduced the time to flowering by 11 days, increased uniformity of flower bud …  Read more

The activation of the protein tyrosine kinase (PTK) ZAP-70 is fundamental to T cell receptor (TCR) signal transduction. TCR engagement induces raft-association of ZAP-70 and juxtaposes the cytoplasmic ZAP-70 with the raft-enriched Lck, which phosphorylates and activates ZAP-70. The active ZAP-70, cooperatively with Lck, initiates multiple intracellular pathways eventually leading to T cell activation and IL-2 production. Here, we describe the serine phosphorylation on ZAP-70 on the highly conserved S520DVWS524 motif, and investigate its role in coupling ZAP-70 with TCR signal transduction.  Read more

Mon thèse, intitulé « Apprivoiser la machine: Le Néo-républicanisme et l'État administratif bureaucratique moderne », porte sur la tension au sein de la théorie politique néo-républicaine entre la nécessité de recourir à un État administratif bureaucratique moderne pour instituer la non-domination et la crainte que la bureaucratie ne représente elle-même une forme de domination structurelle, impersonnelle ou sans agent. D'une part, des philosophes politiques néo-républicains tels que Philip Pettit et Frank Lovett conçoivent la domination comme une relation structurelle entre agents, c'est-à-dire une relation dans laquelle un agent a le pouvoir d'interférer arbitrairement avec un autre agent. Ils rejettent donc …  Read more

This thesis deals with the issue of augmenting public resources with fixed size dedicated (private) resource pools to increase the probability of meeting the service level agreements (SLAs). Since service hosting systems based on virtual machines (VMs) are becoming increasingly practical, this thesis proposes an VM-based infrastructure for outsourcing computer services in public computing utility. Several service-oriented heuristics are proposed to perform resource management in migrating the VMs in order to obtain higher levels of quality of service. Through extensive simulations, this thesis evaluates the performance of the heuristics under different conditions.  Read more

Veronique Bohbot (Internal/Supervisor)  Read more

Trois méthodes optimales de commande à retour d'état complet sont proposées ici afin d'accomplir les exigences du vol intérieur d'un ballon dirigeable holonomique, et ceci, en temps réel. Les manoeuvres exigées incluent le maintien d'une position stationnaire, le mouvement vers un point et suivant une trajectoire continue. Pour la régularisation, un modèle quasi-stationnaire du ballon est assumé et un régulateur quadratique-linéaire (LQR) à horizon infini est utilisé dans un mode d'échelonnage des gains. De plus, les mouvements vers un point sont accomplis en se basant sur le retour d'état pour résoudre l'équation de Riccati qui en dépend et pour compenser …  Read more

Cette étude quasi-expérimentale a examiné les effets de deux techniques de rétroaction, reformulations et incitations, sur l'acquisition des verbes réguliers et irréguliers au passé (en anglais) par des apprenants chinois. Les hypothèses de recherche étaient les suivantes : 1) les apprenants qui reçoivent une rétroaction corrective dans le cours d'activités de communication seront plus performants que les membres du groupe témoin qui réalisent seulement les activités de communication ; 2) les incitations auront davantage d'effets bénéfiques que les reformulations dans l'apprentissage de verbes réguliers au passé ; 3) les reformulations seront plus avantageuses pour l'apprentissage de verbes irréguliers au passé. …  Read more

We have developed new techniques, which enable us to study the kinetics of phase transitions in situ. By resistive self heating of samples, heating rates of over 10$ sp4$ K/s have been achieved. Our methods allows us to acquire x-ray diffraction patterns as quickly as every 3 ms. We have used these new techniques of time resolved x-ray diffraction experiments to study the crystallization kinetics of amorphous NiZr$ sb2,$ CoZr$ sb2,$ FeZr$ sb2$ and Ni$ sb{36.5}$Zr$ sb{63.5}.$ The experiments were performed at beamline X20C National Synchrotron Light Source. We have mostly focussed on the crystallization behaviour at high temperatures and …  Read more

There is a class of plate buckling problems in which buckling occurs in the presence of a constraining medium. This type of buckling has been investigated by many researchers, mainly as buckling of elastic columns and plates on elastic foundations. Analytical solutions have been obtained by assuming the foundation to provide tensile as well as compressive reaction forces. The present work differs from the previous ones in two respects. One, the foundation is assumed to be one-sided, thus providing only the compressive resistance. Two, the plates are allowed to be stressed in the plastic, strain-hardening range. Equations for determining the …  Read more

Three Scenes in Dreamland is a 17-minute piece for mixed choir and instrumental ensemble. It consists of three movements: "Crystal Sky," "The Chanting Light" and "The Field Where I Was Born, Where I Died." Each movement uses a particular combination of the available instruments. The work is inspired by various aspects of Chinese culture and Buddhism, and certain possibilities of combining Western and non-Western musical elements are explored over the course of the three movements.  Read more

Varro, Daniel (Supervisor2)  Read more

Immune cells participate in tumor immune surveillance by causing inflammation and a direct cytotoxicity against tumor cells to prevent their growth and inhibit metastasis. However, as a tumor grows, the tumor microenvironment changes, and immunosuppressive cells are recruited to enhance tumor growth and metastasis. Additionally, to maintain homeostasis, chronic inflammation leads to immune suppression which further enhances tumor growth and metastasis. Using models of inflammation (ECM, EAE, DSS-colitis), it has previously been demonstrated that CCDC88Bmut, ARHGEF2-/-, and RASAL3-/- mice experience altered inflammatory responses because of altered immune cell motility and a decrease in maturation of T cells. The genotypic effect …  Read more

Crist, Colin (Supervisor2)  Read more

The objective of this thesis is to review current approaches for the specification of design loads for rime ice and to propose improvements based on an analysis of field data provided by Hydro-Quebec. Hydro-Quebec established an experimental site on Mont Belair in 1994 for the purpose of obtaining much more detailed data on ice accretion in real time for both glaze ice and rime ice. In this study, rime ice events were identified, analyzed and characterized in terms of their recurrence, severity and relationship to winds. IEC-60826 (2000) recommended procedures are used to calculate design rime ice and wind-on-ice loadsusing …  Read more

This thesis studies the issues on sustainability with nonrenewable resources and on practical problem with environment: regulation to control pollution. The first essay proves the converse of Hartwick's rule with general production function. Hartwick's rule shows that if one reinvests all the rents from nonrenewable resource, then constant sustainable consumption can be maintained. This ensures intergenerational equity. The converse of Hartwick's rule is proved by directly solving ordinary differential equations. It means the constant consumption must imply the total reinvesting of the rents from the exhaustible resource, and so the Hartwick's rule prescribes the unique sustainable policy. In the second …  Read more

Regulators of G protein signaling (RGSs) are negative regulators of G protein coupled receptors (GPCRs). Our lab has demonstrated that yeast Saccharomyces cerevisiae is a useful system to study RGS and G protein signaling. Mammalian RGSs can be expressed in yeast and favored to interact with mammalian GPCRs as well. Based on the observation that human RGS1 causes yeast cell growth arrest, I therefore used RGS1 expressing yeast cells to screen a mouse T cell cDNA library in order to find potential interacting proteins. From the screen, I identified a mouse sphingomyelin synthase 1 (SMS1) cDNA. By using a series …  Read more

Long, Rong (Supervisor2)  Read more

Lachapelle, Kevin J (Internal/Cosupervisor3)  Read more

In melanoma cells, activation of the MAPK and PI3K-AKT pathways is involved in melanoma initiation and progression. In BRAFV600E mutant melanoma, aberrant BRAF activity leads to MAPK pathway overactivation while additional PTEN loss of function will lead to PI3K-AKT pathway overactivation, consequently causing melanoma initiation and progression. Understanding the molecular mechanisms behind the regulation of these two vital pathways in cancer cells is crucial for developing future therapeutics to reduce oncogenesis and prevent cancer progression. The mitogen-activated protein kinase (MAPK) interacting protein kinases (MNK1/2) are activated downstream of the MAPK pathway. The best-studied function of MNK1/2 is their phosphorylation of …  Read more