McGill University Thèses et mémoires par auteur commençant par A

A scarcity of proteins suitable for the supplementation of animal feeds has existed for several years. Present indications are that this shortage is likely to continue, in view of an expanding livestock industry, increased consciousness of the importance of proteins on the part of feeders, and the world food situation in general. Consequently, a widespread search is being conducted for new materials to serve in this capacity, and information on their efficiency as protein supplements is important with a view to recommending their most efficient use. The most acute shortage has occurred in the case of proteins of animal and …  Lire la suite

The problem of fault diagnosis in digital circuits is composed of two sub-problems: Fault detection (identifying that a fault is present) and fault location (identifying the failure responsible for faulty behaviour). Tests using randomly or pseudo-randomly selected input stimuli have been suggested both as a means of reducing the costs associated with generating deterministic tests and as a means by which circuits could test themselves (built-in self-test). The majority of research into random testing has dealt only with its fault detection properties. Fault location has typically been treated as a dictionary search problem, or ignored altogether. This dissertation proposes a …  Lire la suite

This paper undertakes to develop an in-depth interpretation of Piranesi's Il Campo Marzio. While drawing heavily from specific details in both the text and images, the study retains a contextual outlook, speculating that Vico's New Science can lend meaning to Piranesi's work. Based primarily on Vico's concept of the Ideal Eternal History, parallels are drawn between the two works. While this provides the key to entering into Piranesi's work, it reveals only its inner horizon, merely describing in different terms what is already there. The insights provided by this exercise, however, demonstrate that the making of architecture as promoted by …  Lire la suite

Le système de direction de la tête (HD) est communément décrit comme une boussole neuronale. Cependant, contrairement à une boussole magnétique, l'orientation du système HD est dynamique, s'ancre aux indices environnementaux locaux et se réaffecte à travers des environnements familiers. Alors que le signal HD du cerveau est généré et maintenu par des mécanismes internes, la mise à jour de cette représentation interne de la direction nécessite l'intégration d'informations sensorimotrices externes provenant de plusieurs sources. Il est important de noter que les manipulations d'indices visuels suffisent à elles seules à réorienter cette représentation indiquant ainsi l'influence dominante de l'entrée visuelle …  Lire la suite

This thesis reports on research conducted on the Optimal Reconfiguration (OR) of distribution networks using Mixed Integer Linear Programming (MILP). At the operational hourly level, for a set of predicted bus loads, OR seeks the optimum on/off position of line section switches, shunt capacitors and distributed generators so that the distribution network is radial and operates at minimum loss. At the planning level, OR seeks the optimum placement of line switches and shunt capacitors so that, over the long-term, losses will be minimized. The main steps and outcomes of this research are (i) the development of a simplified single-phase distribution …  Lire la suite

Carbon fiber reinforced cyanate ester composites are of interest for space structural applications where not only specific strength and stiffness are required but also dimensional stability and resistance to microcracking. However, because those materials are relatively new, there is a lack of knowledge with respect to their thermal cycling behavior and the related damage mechanisms. This thesis focused on studying the microcracking behavior of a carbon reinforced cyanate ester composite in order to understand the conditions under which microcracking initiates, and it also investigates the impact of microcracking on mechanical behavior. We have investigated the performance of such composite for …  Lire la suite

Allyl propargyl ethers undergo cobalt-mediated cycloisomerization reactions to form dihydrofurans in good yield and with excellent diastereoselectivity. The reaction is proposed to proceed by way of an allylic C-H activation and a formal 5-endo-dig cyclization. The reaction works with a range of allylpropargyl ether substrates. 1,6-Enynes and allyl propargyl ethers undergo a cobalt-catalyzed formal 5-endo-dig cyclization to form vinyl cyclopentenes and dihydrofurans, respectively. The use of equimolar amounts of dicobalt octacarbonyl and trimethyl phosphite affords optimum yields and improved selectivity for cycloisomerization vs. alkene isomerization. The utility of the cycloisomerization reaction is exemplified through the synthesis of the bis-tetrahydrofuran core …  Lire la suite

Le VIH-1 requiert plusieurs protéines cellulaires à chaque étape de son cycle de réplication pour assurer une réplication efficace. Notre travail a mené à l'identification que l'ARN génomique du VIH-1 n'est pas un substrat pour la dégradation des ARNm aberrants (NMD), même si elle a plusieurs cadres de lecture ainsi qu'une longue 3'UTR. Nous avons démontré que UPF1 est impliqué dans la stabilité de l'ARN génomique du VIH-1 car la surexpression de UPF1 a engendré une augmentation des niveaux d'ARN du VIH-1 et de Gag. Par ailleurs, le rôle de UPF1 est distinct de son rôle dans le mécanisme NMD, …  Lire la suite

L'énergie électrique est responsable d'un pourcentage important de la consommation énergétique mondiale et les sources d'énergie électrique non pures représentent encore un quart du bouquet énergétique dans les pays développés comme les États-Unis d'Amérique. De plus, avec l'augmentation prévue de la demande d'électricité due à l'utilisation croissante des véhicules électriques et d'autres dispositifs intelligents tels que les équipements de maison intelligents, le problème des ingénieurs électriciens est de réduire les émissions de l'électricité afin d'atteindre les objectifs de réduction locaux et globaux tout en fournissant suffisamment de ressources pour la demande croissante. Une excellente façon de procéder consiste à incorporer …  Lire la suite

The factors that regulate dystrophin accumulation, and its association with other proteins in culture, are largely unknown. In this study I have examined the effects of chemical agents on dystrophin accumulation in culture, as well as determined whether dystrophin in culture has associations with glycoproteins in a similar fashion to that found in normal muscle tissue. My results show that the onset of detectable dystrophin accumulation occurs shortly after myoblast fusion has taken place, and increases rapidly thereafter as a percentage of total cell protein. The effects of depolarizing concentrations of potassium ion, resulting in the inhibition of myotube contraction, …  Lire la suite

Le lait humain contient une communauté complexe et dynamique de bactéries. Ces bactéries, par le biais de la lactation, contribuent de manière significative à l'établissement du microbiote intestinal du nourrisson, un facteur essentiel pour la croissance de l'enfant. Le microbiome intestinal maternel est l'une des origines du microbiome du lait maternel, qui est fortement associé au régime alimentaire de la mère. Cependant, cette association n'a pas encore été étudiée parmi les populations indigènes ou dans le cadre du régime alimentaire guatémaltèque. Il est prouvé que les souches bactériennes partagées entre le microbiome de l'intestin maternel et du lait et le …  Lire la suite

The first reports on toxin-neutralizing substances date back to the early 1890's, when Metchnikoff demonstrated that Bacillus subtilis was able to produce substances which neutralized diphtheria toxin, tetanus toxin and snake venom after a period of "in vitro" combination. It was further shown that fungi, such as Isarias, Sporotrichous and Torula, parasites of insects and human parasites, destroyed the toxicity of various bacterial toxins (Metchnikoff, 1897).  Lire la suite

The heating, or sheet reheat, phase in thermoforming is the focus of this work. The first objective is to develop a reliable state-space model of this process for simulation analysis. The second objective is to develop a simple linear real-time in-cycle controller for the sheet reheat phase. This controller will improve part quality, decrease energy expenditures and machine wear, and optimize heating time by assuring a desired sheet temperature distribution. The final result is a reduction in production cost per part for the thermoforming industry. A sheet model is developed from first principles, and improved through the addition of energy …  Lire la suite

This dissertation deals with Ibn Taymiyya's theory of the unity of God and of creation, or, as Muslim philosophers have posited the question, the relation between the oneness of God and the diversity that has come out of it. Indeed, Ibn Taymiyya (d. 728/1328) responded to the same ontological question that earlier Muslim philosophers were concerned to answer. Although Ibn Taymiyya was a theologian, he did not encounter quite the same questions as the early kalam theologian whose concern it was to prove the existence of God. The dissertation discusses the forms this question took. The introduction reviews Ibn Taymiyya's …  Lire la suite

The conception of the unity of God in al-Juwayni, one of the latest thinkers in the early Islamic kalam, is the subject of this thesis. Al-Juwayni, though an Ash'arite thinker was quite often open to Mu'tazilite thought, particularly that of Abu Hashim al-Jubba'i. He was also influenced by the philosophers. With al-Juwayni the kalam's theory of the unity of God reached its ultimate resolution. That is to say, the theory of the unity of God was based on specific epistemological grounds, in the early period of the kalam. It had assumed its shape, and was therefore open to the possibility …  Lire la suite

Les médicaments stimulants tels que le méthylphénidate (MPH) sont les médicaments les plus fréquemment utilisés pour le TDAH. MPH agit principalement en bloquant le transporteur de la dopamine (DAT). Environ 70% des patients prenant MPH spectacle réponse thérapeutique adéquate, mais le niveau de réponse à MPH varient d'un enfant à l'autre. De même, le niveau de l'effet de côté MPH varie d'un enfant à l'autre et peut être la cause de l'adhésion thérapeutique pauvres. Plusieurs études ont mis en cause la région 3 'non traduite (UTR) répétition en tandem de nombre variable (VNTR) du gène transporteur de la dopamine (DAT1) …  Lire la suite

Intracranial gliomas are the most common primary brain tumors. Despite advances in medicine, patient outcomes have not changed significantly over the last century. The invasive behavior of these cells is the main reason for treatment failure. Cancer invasion and cell motility are topics under intense investigation in cancer research. However, they are less studied in gliomas and the literature describing the molecular mechanisms which govern glioma cells motility is lagging.We have recently reported Down Regulated in Renal cell carcinoma (DRR) as a novel modulator of glioma invasion and migration. Among the interesting findings we observed was the changes seen at …  Lire la suite

Members of the zinc cluster (or binuclear cluster) protein family are characterized by a Zn(II)Cys6 zinc finger involved in DNA recognition and binding. These fungal proteins are transcriptional regulators of genes involved in a wide variety of cellular processes. One member, Gal4p, is involved in galactose metabolism, while others play a major role in primary and secondary metabolism, control of meiosis, and multidrug resistance. Sequencing of the Saccharomyces cerevisiae genome has revealed that 55 genes encoding putative zinc cluster proteins are present in budding yeast. However, the roles of many of these zinc cluster proteins are unknown. In order to …  Lire la suite

Animal models are valuable tools in auditory research. Rats are potentially very useful for this purpose. They are low in cost, they are genetically similar to humans, and the middle-ear structures are easily approachable. The goal of the present study is to better characterize the mechanics of the rat middle ear by measuring frequency responses at multiple points on the tympanic membrane for the first time, and with better frequency resolution than in previous studies. A laser Doppler vibrometer was used to measure the vibrations. Measurements were done on seven rats. Tympanic membrane vibrations at seven different points, in the …  Lire la suite

Talla, Pascaline Kengne (Supervisor1)  Lire la suite

Berk, Dimitrios (Internal/Supervisor)  Lire la suite

This thesis describes a search for DNA polymorphisms at the HEXA locus as well as the characterization of three Tay-Sachs disease (TSD) mutations in the Chinese population. No polymorphisms were detected in the HEXA gene by three different methods: (1) Southern blotting; (2) PCR amplification and restriction enzyme digestion of intronic sequences; (3) single strand conformational polymorphism (SSCP) analysis of introns. The apparent deficiency of accessible polymorphisms is a handicap in studying the origin, distribution, and frequency of mutant HEXA alleles in human populations. I have characterized five of six infantile TSD alleles segregating in three unrelated Chinese families in …  Lire la suite

The need to better understand the fate and behavior of surface-modified engineered nanoparticles upon release into subsurface environments has been heightened by the increase in their production, use and disposal thereby increasing the potential for environmental and health risks. In this study, the effect of cellulase – either suspended in background solution or adsorbed on silica surfaces – on the deposition kinetics of polymer-coated titanium dioxide nanoparticles was examined. A quartz crystal microbalance with dissipation monitoring (QCM-D) was used to study the interaction of the nanoparticles with bare and cellulase-coated silica surfaces as well as in the presence of suspended …  Lire la suite

The family Pyrgomorphidae comprises about four hundred or so known species of grasshoppers, the majority of which are from tropical and subtropical countries, chiefly of the Old World. The morphology, other than that of the phallic complex, has not been critically studied in the course of this work. The following general characters of the group are, therefore, mainly those given by more recent authors such as Slifer (1940a), Laird (1943), Rehn (1953b), Kevan (1955; 1959; 1961a), Dirsh (1956; 1961a) and Helwig (1958). The chief distinguishing features of the family are as follows.  Lire la suite

Striated muscles conduct many essential aspects of life such as moving and heart beating. Sarcomere structure and function as the smallest contractile unit of muscles, is highly conserved throughout evolution. It is composed of actin thin filaments and myosin thick filaments which are confined between two adjacent Z-discs. The Z-disc is a multi-protein complex that serves as an anchor-site for actin filaments. Different Z-disc cross-linker proteins such as α-actinin, filamin and Alp/Enigma proteins are involved in myofibril assembly and maintenance. The Alp/Enigma family is a class of Z-disc-associated proteins, whose mutations lead to myopathies and different muscle disorders. In Drosophila, …  Lire la suite

Indigenous, cold-adapted, hydrocarbon-degrading bacteria have been frequently detected in soils from cold region sites suggesting bioremediation, as a cost-effective remediation technology is potentially viable for cleanup of contaminated sites in cold regions. Previous studies on bioremediation of petroleum hydrocarbons in cold regions have been conducted with coarse textured soils. However, fine-grained or clayey soils are commonly found in several cold regions. The overall objective of this research was to investigate the factors controlling biodegradation of aged, clayey petroleum hydrocarbon contaminated soils from a sub-arctic site, under relevant temperature regimes. The biodegradation rates and extents of petroleum hydrocarbons were investigated for …  Lire la suite

Van de Ven, Theodorus G. (Supervisor2)  Lire la suite

L'ablation par radiofréquence (ARF) est le choix de préférence lorsque des méthodes minimalement invasives sont recommandées pour le traitement du cancer du foie. Classée dans la catégorie de l'hyperthermie locale, la ARF détruit les tumeurs sans chirurgie et utilise plutôt des températures élevées pour cuire les cellules cancéreuses. Cette méthode fonctionne efficacement lorsque la zone cible est maintenue dans une plage de température exacte pendant une certaine durée. Cependant, cette mission n'est pas toujours facile à réaliser tant la température à l'intérieur d'une tumeur est difficile à mesurer avec précision. De plus, pour les tumeurs du foie, le résultat du …  Lire la suite

Cette thèse explore le rôle des frictions d'emprunt, des risques de change, et de la demande intertemporelle des actions dans les marchés financiers internationaux. Plus précisément, j'étudie les prix des actifs globaux, compte tenu des contraintes et des incitations imposées sur les décisions d'investissement. Le premier essai contribue à la recherche sur la dynamique de l'intégration des marchés financiers internationaux. En examinant la liquidité du financement, je fournis une explication sur les inversions du processus d'intégration financière. Je montre que lorsque leur source de financement se tarie, les investisseurs, incapables d'emprunter et de commercer librement, ne parviennent pas à faciliter …  Lire la suite

Background: To date, uncertainty persists regarding the necessity of additional treatment for head and neck cancer (HNC) patients with prior root canal treatments. These patients may be clinically asymptomatic but exhibit specific radiographic risk factors. The dilemma arises as to whether such individuals should undergo further intervention before undergoing radiation therapy (RT). This uncertainty is compounded by the potential for oral complications, spanning from mucosal to bone tissue impairments, and the compromised immune systems commonly observed in patients undergoing RT. However, there is a notable scarcity of studies investigating the effects of RT on asymptomatic root canal-treated teeth in HNC …  Lire la suite

Incompressible, viscous, two-dimensional unsteady flows over bluff bodies are simulated via the use of vortex methods. The vorticity domain is discretized into a number of Lagrangian point vortices. The vorticity transport equation is split into convection and diffusion parts, and each part is solved sequentially, rather than simultaneously, in each time step. The convection equation is solved using a "vortex-in-cell" method, and the diffusion equation is either simulated by a random walk method, or solved using a finite-difference ADI scheme. New vorticity is created on the body surface during each time step in order to satisfy the no-slip boundary condition. …  Lire la suite

The problem of flutter is first introduced. The equations of motion of an airfoil with two degrees of freedom, in pitch and plunge, are obtained. Then, the unsteady aerodynamic theories for different flow regimes are presented. The traditional solutions to the flutter problem, namely, the p-k and U-g methods, are formulated, and the Laplace transformation method for flutter analysis is also introduced. Then, the effect of different design parameters of an airfoil on the flutter speed is analyzed, both in the incompressible and transonic regimes. Furthermore, the effect of the relative values of the design parameters on the occurrence of …  Lire la suite

Les canaux de communications sont vulnérables aux sources de bruit. De ce fait, n'importe quelle donnée transmise sur ces canaux peut être victime d'erreurs survenant lors de la transmission, dégradant ainsi la qualité du signal à la réception. Afin de résoudre ce problème, une certaine redondance doit être apportée au signal d'entrée pour qu'à la réception elle aide à corriger les erreurs. Cependant, la plupart des schémas ajoutant de la redondance aux signaux ont deux défauts majeurs. Premièrement, ces schémas sont conçus pour fonctionner décemment aussi longtemps que la qualité du canal reste au dessus d'un certain seuil. Mais dés …  Lire la suite

This dissertation comprises two parts. In the first part, several extensions of the finite-element time-domain (FETD) method discretized by the Newmark-β (NB-FETD) scheme to dispersive media are introduced. These extensions primarily focus on improving efficiency and stability of the NB-FETD formulation. One of them is a direct discretization of the NB-FETD in dispersive media using the bilinear (Möbius) transformation. It is proven that the eigenvalues of the amplification matrix do not go beyond the unit circle and hence lead to a stable update. The other one combines the mixed FETD in dispersive regions with the NB-FETD in the other parts …  Lire la suite

The process parameters that affect the anisotropy of mechanical properties of two Nb microalloyed linepipe steels (grades X-70 and X-80) were examined by controlled rolling and accelerated cooling on a pilot mill. The rolling schedules were first simulated by multi-pass torsion testing so as to determine the critical temperatures, such as T$ sb{ rm nr}$ and Ar$ sb3.$ Using the torsion test results, two finish rolling temperatures were chosen so as to be above and below the A$ sb3$ (in the $ gamma$ + $ alpha$ region). Two reheat temperatures were selected to study the effect of prior austenite grain …  Lire la suite

Les bandits agités sont une classe de problèmes d'allocation séquentielle de ressources concernés par l'allocation d'une ou plusieurs ressources entre plusieurs processus alternatifs où l'évolution des processus est markovienne et dépend des ressources qui leur sont allouées. En 1988, Whittle a développé une heuristique d'indice pour les problèmes de bandits agités qui est devenue une approche de solution populaire en raison de sa simplicité et de ses solides performances empiriques. L'heuristique de l'indice de Whittle est applicable si le modèle satisfait une condition technique connue sous le nom d'indexabilité.Dans cette thèse, nous nous concentrons sur trois configurations générales : les …  Lire la suite

Constant strain rate compression and torsion tests were carried out isothermally at temperatures of 875 to 1075(DEGREES)C on a series of six steels. The base steel had a composition of 0.06% C and 1.43% Mn and the others contained one of the following sets of additions: (i) 0.035% Nb; (ii) 0.035% Nb + 0.115% V; (iii) 0.035% Nb + 0.30% Mo; (iv) 0.035% Nb + 1.90% Mn; (v) 0.115% V. The tests were conducted to determine the effects of Mn, Mo, Nb and V, singly and in combination, on the high temperature flow and recrystallization behavior of the materials. The …  Lire la suite

Menzies, Richard Ian (Supervisor1)  Lire la suite

Occupationism recently has been introduced and defined as discrimination on the basis of one's occupation (Carson, 1992; Krumboltz, 1991, 1992). In this qualitative study, the existence of occupationism is investigated through the examination of the results of interviews with six funeral directors. The statements of the participants describing occupationist acts (either positive or negative) were classified into a number of categories at both fine-grained and more superordinate levels. Implications of the results for the proposed occupationism construct and suggestions for future research and career interventions are discussed.  Lire la suite

This study is an exploration of the relationship between spirituality and the career-transition process in middle-aged women's lives. The sample of this study consisted of 20 women who were in or went through a career-transition process. The research data were collected through in-depth interviews. Grounded theory methodology (Strauss & Corbin, 1990) was used to analyse the data and to generate frameworks for the interaction between the career-transition process and spirituality. The results indicated three different frameworks to explain the interaction between the two research variables for three different patterns of career-transition process. These frameworks included five major themes related to …  Lire la suite

Rogers, Colin Andrew (Supervisor1)  Lire la suite

Rouleau, Guy (Supervisor1)  Lire la suite

A numerical method is described for determining the derivatives of the scattering parameters of an arbitrary 3D microwave device with respect to changes in model geometry. The new technique is based on the adjoint variable method as applied to finite element analysis, but does not require the separate calculation of an adjoint solution. The new technique is applied to the optimization of the design of microwave components, using a derivative-based, quasi-Newton method. The derivatives of the scattering parameters of three devices are computed and compared to analytical or finite difference values. The agreement is very good. The three devices are: …  Lire la suite

Les récents efforts en matière de justice internationale pénale ont accordé une attention croissante aux victimes de crimes internationaux. Toutefois, le droit international s'intéresse aux victimes depuis sans doute beaucoup plus longtemps. Ce qui est nouveau, c'est la tentative de formaliser et de légaliser le statut des victimes, ainsi que les dilemmes que cela suscite. Par ailleurs, il ne s'agit pas simplement d'octroyer aux victimes certains droits en droit international pénal, mais de leur garantir un statut. Dans ce cadre, le droit international doit constamment arbitrer les dilemmes complexes ayant trait à la nature fondamentale de la qualité de victime. …  Lire la suite

La perte de la biodiversité se produit à un rythme sans précédent, menaçant les services écosystémiques essentiels à la nourriture, à l'eau, et à la santé et au bien-être humains. Comprendre la distribution des espèces est crucial pour la politique de conservation. Cependant, les méthodes traditionnelles de modélisation de la distribution des espèces (SDM) se concentrent sur des espèces ou des régions limitées, laissant d'importantes lacunes dans nos connaissances. Un obstacle clé est l'effort considérable nécessaire pour la surveillance traditionnelle. La télédétection et la science citoyenne offrent des opportunités pour transformer la surveillance de la biodiversité et permettre la modélisation …  Lire la suite