McGill University Thèses et mémoires par auteur commençant par T

The study of the pathogenesis and localization of vestibular and related pathology is in its developmental stage now. Some fascinating and outstanding work has been done in the last few years which has been of great help in clinical otoneurology. However, very few of the problems appear to be clear. As in any other developing branch of medicine, here too, there is a fair amount of controversy and divergent opinions. [...]  Read more

De nombreux auteurs suggèrent que les changements environnementaux d'origine anthropique (c.-à-d., eutrophisation et réchauffement climatique) ont créé des conditions propices pour une dominance globale des cyanobactéries dans les communautés phytoplanctoniques. Cependant, à ce jour, il n'existe pas de synthèse quantitative pour appuyer cette présomption et nous avons très peu d'évidences empiriques des relations synergétiques entre les facteurs environnementaux qui peuvent être responsables d'une expansion des cyanobactéries à travers le temps. Un échantillonnage pluriannuel des lacs, couplé avec des reconstitutions paléolimnologiques s'est avéré une stratégie efficace pour répondre à ces questions. Dans ma thèse de doctorat, j'ai quantifié les tendances temporelles …  Read more

Les études antécédentes ont démontré que les chargements de nutriment diffus parvenant d'activités agricoles sont une cause importante de l'eutrophisation des lacs. Par contre, le degré auquel cette relation peut être extrapolé à l'échelle interrégionale n'a pas été largement étudié. Ma thèse a pour but de définir la généralité et l'impact de l'usage des terres agricoles et la morphométrie des lacs sur la qualité d'eau. Des analyses selon des échelles spatiale et temporelle ont évalué la significativité de ces effets. Dans ce premier manuscrit, nous avons examiné si les activités agricoles pouvaient expliquer une proportion significative de la variation de …  Read more

The general theory of first principles calculations is presented and all equations are derived from basic starting points. In particular, an explanation of density functional theory (DFT) is given, with emphasis on the Hohenberg-Kohn theorem, the Kohn-Sham equations and the local density approximation (LDA). In addition, a description of pseudopotentials, basis sets, self-consistency, and solution methods for the Kohn-Sham equations will also be presented. Using these basics as a foundation, the equations needed to conduct an atomic orbital first principles calculation are then derived. This method incorporates the Harris approximation, LDA, a minimal sp3 atomic orbital basis set, and diagonalization …  Read more

Petroleum is a hydrocarbon known in its liquid state as oil and in its gaseous state as natural gas. It is usually found in the sedimentary basins which make up about one-third of the earth's land surface. Well over a century ago, it came into increasingly general use as a lubricant, and through one of its many derivitives, kerosene, as an energy source. This latter use has since been enhanced powerfully by the rapid industrialization of the western world, the invention of the combustion engine, the decline of coal, and numerous other developments that have characterized the twentieth century.  Read more

The market becomes inefficient when externalities cause market failure. However, an externality does not entrain inefficiency if a market other than the one that generates it accounts for it in some way. Airports are a well-known source of the negative externality noise; and housing market are commonly thought to be affected by airport noise. A hedonic model was applied to airport noise and the housing market, together. It was found that the housing market of the West Island of Montreal did account implicitly for the noise annoyance from Dorval Airport, hence that the noise was a pecuniary externality. Moreover, each …  Read more

Most of the recent studies on the southern Jordan Bedouins portray the Bedouins as being resistant to change and development. These studies are more descriptive than analytical, focusing on romantic aspects of the Bedouin's lifestyle. In contrast, this study, based on fieldwork conducted in Wadi Rum between June-November 2004, attempts an ethnographical study that does not represent the Bedouins in a stereotypical way, neither romanticising them nor treating them as in need of development. It is based on an examination of the relationship between the socio-cultural, economic and political aspects of Bedouin society and the physical environment in which they …  Read more

In the last three decades due to urbanization and modernization, the social, cultural, political, and economic life of the Bedouins of Jordan underwent several changes. As a result of the sedentarization process, which started in the beginning of 1970's, the Bedouins moved from a nomadic to sedentary life-style in which their customs, their houses, and their ethnic habits were deeply influenced. Their new settlements remind more of the Jordanian suburban landscape that characterizes most of the urban centers. These settlements provided them with dwelling units influenced by some of the western planning models. To explore the issue of housing design …  Read more

Harvey, Edward (Internal/Supervisor)  Read more

This work focuses on the similarity of percepts, that is, how individuals could have similar internal, subjective, and conscious experiences of the perception of sensory stimuli. It has been suggested that consciousness emerges from specific patterns of firing in particular subsets of neurons. However, that specificity contrasts with the large differences that can exist between individual brains. It also appears inconsistent with the fact that the nature of a percept does not seem to ultimately be constrained by either the physical stimulus itself or the brain areas that contribute to its processing. Using this logic, there would be no way …  Read more

Immunohistochemistry (IHC) and advanced magnetic resonance imaging (MRI) studies over the last decade have corroborated that grey matter (GM) structures are extensively involved in multiple sclerosis (MS) pathology, revolutionizing the long time perception of MS as a white matter disease. Yet cortical GM lesions remain notoriously difficult to detect in vivo using MRI. The main objective of this thesis was to create a quantitative MRI acquisition and analysis framework for the study of cortical MS pathology in vivo. To achieve this, two complementary approaches were used: brain morphometry and quantitative imaging of magnetic resonance properties (qMRI). The first aim was …  Read more

Efficient muscle regeneration is essential in mammals in order to overcome daily stress such as wounds, exercise and pathologic processes. This regeneration relies on muscle stem cells, the satellite cells. After a lesion, satellite cells are activated, proliferate and differentiate in fonctionnal muscle fibers. Our laboratory has previously shown that the transcription factor GATA-6 is expressed in the satellite cells. The present thesis confirms the expression of this factor in this cell type. Also, it seems that GATA-6 could be implicated in the maintaining of quiescence of these cells. The GATA-6 heterozygous mouse muscle is characterized by an increase level …  Read more

This thesis offers an analysis of the intertextual practices in Marie-Claire Blais's trilogy Soifs by which we explore the way the author integrates into her novels significant literary figures and texts in order to underline one of the trilogy's constant themes: the innocence and suffering of the victims of the twentieth century and of today. In this fiction saturated with literary and artistic references, literature appears as a standpoint on modern world and works are considered to be acts of creation that opposes to the "choeur de la destruction" the voices of writers and artists.  Read more

A three-dimensional aeroelastic solver using the Nonlinear Frequency Domain (NLFD) method in conjunction with a novel dynamic mesh deformation approach using Radial Basis Functions (RBF) is developed. A structured multiblock finite-volume flow solver coupled to a plate bending finite-element model is employed for aeroelastic computations. The novelty of the developed dynamic mesh deformation method consists in the computation of the mesh velocities using the RBF matrix operator for use in the Arbitrary Lagrangian-Eulerian formulation of the flow governing equations. The approach is validated for a pitching two-dimensional NACA 0012 airfoil and a pitching three-dimensional LANN wing against the rigid grid …  Read more

Greer, Charles William (Internal/Supervisor)  Read more

A temperature dependent NMR study revealed that dibenzyloxy disulfides can deliver singlet diatomic sulfur S2. The thermolysis was studied in different solvents in the presence of different dienes. The disulfide adduct and the diene were comparably competitive for the S2 transfer. Tetrasulfide adducts were obtained in the presence of dimethyl and diphenyl butadiene, but converted to the disulfide adduct upon triphenylphosphine treatment. The related "oxytrisulfide" was demonstrated to also transfer the S2 unit to dienes. A brief analysis of a known thionosulfite has shown its potential to transfer S2 units to dienes. Mechanistic considerations were proposed to rationalize the olefinic …  Read more

Les aéronefs à voilure tournante ont des missions qui les exposent occasionnellement au risque de givrage en vol, un phénomène qui peut devenir catastrophique s’il n’est pas contrôlé. Le rotor principal d’un hélicoptère est responsable de la génération de la portance ainsi que du contrôle des axes de tangage et de roulis, et il est donc critique de protéger ce composant du givrage. Les systèmes de protection contre le givrage utilisés par les hélicoptères diffèrent de ceux des avions à voilure fixe dû au volume interne restreint des pales ainsi que de la puissance limitée des moteurs d’hélicoptères. Les systèmes …  Read more

Demand Forecasting is an important tool in many industries including retail. Althoughmany approaches have been developed to accurately predict the demand of productsbased on their historical sales data, demand prediction is still a complex issue especiallywhen there is a domain shift between training and testing data.In this work, we study three examples of domain shifts in the context of retail: outbreak ofthe COVID-19 pandemic, opening a new store, and introducing a new product. We firstshow that the accuracy of demand prediction models suffers after each sudden change.Then, we use domain adaptation methods, such as Frustratingly Easy (FE) and KernelMean Matching …  Read more

The fundamental motivation for the work in this thesis is the analysis of the optimal control of hybrid systems on Riemannian manifolds using the language of differential geometry. Hybrid systems theory constitutes one of the major frameworks within which one may model and analyze the behaviour of large and complex systems; in particular, the optimal control of hybrid systems has been a focus of research over the last decades resulting in the important generalization of Minimum (Maximum) Principle of classic optimal control to hybrid systems. In the work of Shaikh and Caines (2007) and their predecessors, a formulation for a …  Read more

This research project aimed at the development of a PECVD process for the deposition of C60-PPPE (plasma polymerized polyethylene) NC thin films. A continuous throughput PECVD system was designed for the co-deposition of a polymer matrix and C60 particles, in effect, yielding composite thin films on 1" quartz and silicon substrates. In this process, the C 60 molecules are sublimated from their solid powder form, transported to the plasma chamber, pre-coated in-flight before being dispersed and co-deposited in the polymeric matrix. The plasma polymerization of ethane in the low pressure, radio frequency (RF) plasma was studied with a mapping of …  Read more

Donald L Smith (Supervisor1)  Read more

Quadrotors are highly agile vehicles that can be used to perform aggressive maneuvers. Commanding a quadrotor to perform a maneuver that is beyond the physical capabilities of its actuators leads to actuator saturation. A prolonged state of saturated actuators can cause the vehicle to behave unpredictably. This work investigates the use of constrained control allocation methods in a cascaded control structure to mitigate the adverse effects of actuator saturation. More specifically, a constrained weighted least squares approach is used in the position controller and mixer to prioritize certain control efforts while considering constraints on the actuators and, optionally, vehicle attitude. …  Read more

Air-Assisted Solvent Extraction (AASX) is a novel concept that uses a solvent-coated bubble to contact the organic and aqueous phases. The advantages over conventional solvent extraction (SX) are high solvent to aqueous contact area with reduced solvent volume and ease of phase separation due to the buoyancy imparted by the air core. This opens the way to treat dilute solutions (<1 g/L), such as effluents. The novel contribution in this thesis is the production of solvent-coated bubbles by exploiting foaming properties of kerosene-based solvents. The basic set-up is a chamber to generate foam which is injected through a capillary (orifice …  Read more

The sound of our urban environments, framed as urban noise, is an increasing concern as cities develop, diversify, and densify, impacting both well-being and quality of life for a majority of the urban population. But, in many environments, reducing sound levels has proven insufficient to improve the quality of the urban auditory experience. The soundscape approach considers sound as a resource in sonically complex urban environments, rather than only a pollutant to be eliminated. Accordingly, soundscape research has demonstrated the potential for positive and restorative qualities of sound environments. Additionally, an approach that views sound as a resource allows for …  Read more

Modern high-performance architectures are increasingly relying on dynamic branch prediction mechanisms to reduce the impact of branches on system performance. Most dynamic schemes use a table of state counters associated with specific branches, coupled with a buffer recording recent branch outcomes to correlate the behaviour of individual branches with the history of other recently executed branch instructions. The combination generally yields a higher prediction rate than branch-specific counters alone. There is always a question of how much correlation to use and recent studies have reported that some programs benefit from higher levels of correlation than others. In our preliminary studies, …  Read more

The structure and relationships among the various cerebrospinal nerve roots concern an understanding of each of the highly specialized constituents of both the central and peripheral nervous systems. It is not surprising, therefore, that information upon this subject is scattered through a vast literature under a variety of titles. The earliest studies on the histology of the cerebrospinal nerves ooncerned the nerve fibers for the obvioas reason of their susceptibility to the simpler technical procedures then in vogue. [...]  Read more

Vitus Bering discovered Alaska under the sponsorship of Peter the Great and Catherine I. The Russian American Company emerged as the principal trading company. Military considerations, financial pressure and friendship with the United States were among the factors that occasioned the offer. America accepted because of the cordial relations, desire for expansion and appreciation of the intrinsic value of Alaska. Reactions to the sale in the United States, Russia and Russian America, Canada, Great Britain and other European countries are discussed in this study.  Read more

Human newborns' response to decreased sound pressure level (SPL) was investigated with a localized headturning habituation procedure. Following criterion orientation (three headturns toward the sound out of four consecutive trials) and habituation (three consecutive trials with no headturns or headturns away from the sound), study 1 and 2 assessed newborn female infants' (M age = 41 hrs.) responses to lower-volume sounds immediately following habituation and following a 55-sec delay, respectively. Generalization of habituation to decreased volume following delay with recovery immediately following habituation was observed. Immediate recovery to decreased SPL contradicts a selective receptor adaptation view because a lower-intensity stimulus …  Read more

The under-representation of women in science-related fields has serious economic and social implications as Canada is confronted by a shortage of scientists especially in engineering and the applied sciences. The purpose of this study was to investigate similarities and differences between second-year female college students (N = 79) who intend to pursue pure and applied sciences (PAS), and their male counterparts (N = 81), and between PAS females and females who intend to pursue health sciences (HS) (N = 85). The study investigated the relative importance of motivational, self-concept-related, and sociopsychological variables on women's science college majors. The following measures …  Read more

The synthesis of a polysaccharide (levan) from simpler carbohydrates both by the agency of Bacillus subtilis Cohn and Bacillus mesentericus Trevisan has been studied. The action of both these organisms is apparently specific in that they only bring about polysaccharide formation from sugars containing a terminal fructofuranose residue in their molecule. A similar synthesis can be carried out by employing the corresponding enzyme-preparation from Bacillus mesentericus. The bearing of these results on the known fact that yeast invertase only exerts its hydrolytic action on sugars containing a terminal fructofuranose group is discussed in detail. [...]  Read more

The concept of development risk is new in product liability. Its emergence is related to the evolution of production methods, the increased improvement in scientific knowledge, as well as the general trend towards a better consumer protection. This notion has appeared first in the United States as "state-of-the-art defense". It has recently been received in Europe, examplifying a phenomenon of transplantation of legal concepts, here into a Civil Law system such as the French one. The concept of development risk also has an impact on the very foundation of the liability regime, and requires that a choice be made between …  Read more

[...] Pour les raisons énoncées précédemment, il nous a semblé important d'étudier quelles étaient les réactions du champignon lorsqu'il venait en contact avec les substances naturellement présentes à la surface des feuilles, quelle était lat nature de ces substances et leur rôle dans l'établissement de la maladie et aussi comment une fois la maladie établie, le champignon pouvait affecter la nature et la quantité de ces substances qui sont perdues par les feuilles sous l'action de la pluie. [...]  Read more

Ratzer, G. (Supervisor)  Read more

This thesis is an examination of Mulla Hadi Sabzawari's commentary (1797--1878 or 1881) on the Mathnawi of Jalal al-Din Rumi (d. 1273), entitled Sharh&dotbelow;-i Asrar-i Mathnawi. The purpose of this study is to analyze Sabzawari's approach and investigate how this synthesizer of the philosophy of Mulla S&dotbelow;adra and Suhrawardi interprets Rumi's message. Moreover, I will assess the details of his arguments and philosophical interpretations of Rumi's verses. Chapter one is a brief introduction to Rumi's biography and his works as well as a review of the commentary tradition on his Mathnawi. In chapter two a full account of Sabzawari's life, …  Read more

The ultimate objective in this research was to determine quantitatively the individual amounts of primary and secondary alcohol groups in an alkali soluble , commercial hydroxyethyl ether of cellulose. The methods proposed for this study had previously been perfected on various other derivatives of cellulose, starch and sugars (1, 2, 3, 4). These methods depended on the fact that the p-toluene sulfonyl (tosyl) esters of primary, as opposed to secondary, alcohols gave quantitative yields of alkyl iodide when treated with sodium iodide in a ketone solvent. However, it was considered advisable first to apply the same techniques to simpler compounds …  Read more

This thesis contains a collection of results in computational geometry that are inspired from music theory literature. The solutions to the problems discussed are based on a representation of musical rhythms where pulses are viewed as points equally spaced around the circumference of a circle and onsets are a subset of the pulses. All our results for rhythms apply equally well to scales, and many of the problems we explore are interesting in their own right as distance geometry problems on the circle. In this thesis, we characterize two families of rhythms called deep and Euclidean. We describe three algorithms …  Read more

Éléments d'optiques diffractives (EODs) composent une partie essentielle dans le succès de microsystèmes optiques. Lithographie à faisceau d'électrons est un élément clé pour la fabrication des structures avec des dimensions critiques submicroniques. Cette thèse présente le travail fait sur le développement d'un processus pour la fabrication des optiques diffractives en utilisant cette méthode. Ce projet étudie des divers défis impliqués dans ce processus, traite des problèmes qui pourrait surgir et propose des solutions pour les résoudre. Les sources d'erreur possible dans la création et le transfert des modèles sont identifiées et des méthodes de les éliminer ou les minimiser sont …  Read more

The market life of many fruits and vegetables can be extended through storage at low temperatures. Chilling injury (CI) is a major postharvest storage problem for tropical commodities. Storing these products at temperatures below their critical temperature may result in severe physiological disorders known as CI symptoms. Mangoes (Mangifera indica. L) are susceptible to CI when stored below 12 °C. Visual CI symptoms include uneven ripening, surface pitting, discoloration, shriveling and scalding. Research has been conducted to overcome these serious problems using various postharvest treatments such as hot water, methyl jasmonate (MJ) or diphenylamine (DPA) with some reduction of the …  Read more

Hassan Benchekroun (Supervisor2)  Read more

Le Flysch a Helmintho(')ides et son substratum de shales noirs constituent des facies extremement repandus des nappes de flysch neocretaces alpins. Malgre ses implications paleogeographiques, la sedimentologie de ces unites reste mal connue. Pour contribuer a combler cette lacune, cette etude s'interesse a un des Flysch a Helmintho(')ides classiques et a son Complexe de base. Le Complexe de base est constitue de shales noirs associes a des carbonates authigenes. La petrographie, la diffraction X, la microsonde et l'analyse isotopique du carbone sont appliquees a la description de ces carbonates qui ont pour compositions moyennes: dolomite: Ca(,1).(,02) Mg.(,42) Fe.(,24) Mn.(,32)(CO(,3))(,2); rhodocrosite: …  Read more

Biamonte, Nicole (Supervisor2)  Read more

This thesis presents a method for evaluating the performance of computer systems. The method is based on generating a graphical model of the system using Petri nets and simulating that model to obtain the required performance measures. The collected performance indexes are then analyzed to determine the functionality of the modeled system. The method we present is a hybrid implementation of two very powerful strategies, namely: Petri nets and object-oriented programming. The Petri net model is used to generate precise graphical representations that can model such aspects as synchronization, parallelism, control flow, and data flow. Furthermore, we will emphasize the …  Read more

Vedel, Isabelle (Internal/Supervisor)  Read more

Radio interferometric images have revealed that concentric dust rings are a common feature of protoplanetary disks. These rings provide observational evidence that there are mechanisms to slow and even halt the expected rapid inward radial drift of dust particles. As they are areas of high density, they are also thought to be potential sites for planetesimal, and eventually planet, formation. How efficiently the dust grains collect into these rings is dependent on the source of pressure perturbations in the disk gas and the size of the grains themselves. We investigate this dust trapping efficiency and the dust-gas dynamics within the …  Read more

Les étudiants qui débutent leur première année d’université font face à de nombreux nouveaux défis, notamment une diminution de leur niveau d'activité physique et de leur bien-être psychologique. Une intervention d'activité physique pourrait être un moyen efficace d’alléger ces inquiétudes chez les étudiants universitaires, en raison des bienfaits psychologiques de l'activité physique. Le contraste mental est une stratégie d'autorégulation qui consiste à établir un objectif, puis à comparer les résultats positifs et les obstacles actuels associés à cet objectif. Le contraste mental améliore une variété de comportements liés à la santé de façon efficace. Plus particulièrement, il a été démontré …  Read more