McGill University Thèses et mémoires par auteur commençant par Z

This research investigated how cold temperatures affect oil/water partitioning of two commonly encountered aromatic hydrocarbon pollutants, naphthalene and benzene. Although it is generally assumed that equilibrium concentrations of organic solutes decrease with temperature, there is little data on oil-water partitioning coefficients of environmentally significant solutes or methodology description for the calculation of such coefficients. Partitioning experiments showed that equilibrium aqueous concentrations were found to depend largely on a single compound property, the excess heat of solution of the compound. Equilibrium concentrations of naphthalene decreased with decreasing temperature between 25ºC and 8ºC. But for those compounds exhibiting a solubility minimum at …  Lire la suite

This thesis proposes an efficient power system simulator to estimate the automatic sequence of events that follow a fault contingency leading to islanding and cascading outages. The simulator is based on a quasi-steady state model that includes island identification, under-frequency load shedding, over-frequency generator tripping, and island load flow. Contingencies can include the outage of generators, loads, or transmission lines. Often times, a fault of one or two of these power system elements can lead to many cascaded outages and system islanding. The simulator utilizes an innovative method that analyzes the null space of the DC load flow susceptance matrix …  Lire la suite

An experimental test program was conducted at McGill University which incorporated 14 castellated steel beams provided by Chaparral Steel. The notable feature of these beams is their thin webs. The modes of failure and their corresponding loads were predicted based on a number of previous studies. A nonlinear finite element analysis was carried out in order to provide a new assessment tool. The program used was NASTRAN. The geometrics of the castellated steel beams were predicted to be susceptible to web post buckling. The applied load which causes the formation of the mechanism failure (Redwood 1978), and the load which …  Lire la suite

Le Diabète Insipide Central est un désordre qui est caractérisé par la sécrétion diminuée d'une certaine hormone dans le corps humain appelé l'hormone antidiurétique (ADH). Les patients affectés par cette anomalie auront un taux anormalement élevé d'osmolalité du plasma, manifesté par une diminution de la concentration de l'urine et par un excées de soif et de production d'urine. fr Actuellement, on traite le Diabète Insipide Central en administrant de l'ADH synthétique avec un vaporisateur nasal. Dans cette thèse, un système de traitement automatisé a été etudié. A cette fin, des techniques de contrôle avancées ont été étudiées, à savoir le …  Lire la suite

Le siècle dernier a été témoin d'une révolution dans notre compréhension des facteurs héréditaires influençant une multitude de traits humains. Cette révolution a été stimulée par la découverte que ces facteurs sont codés dans une structure moléculaire appelée ADN, que nous pouvons maintenant lire et déchiffrer à grande échelle. Ainsi, les instituts de recherche du monde entier ont récemment commencé à répertorier l'ensemble des variations génétiques et phénotypiques humaines dans des bases de données harmonisées, ou « biobanques ». Les initiatives les plus importantes comprennent des données provenant d'un demi-million d'échantillons, dont les séquences génomiques complètes sont associées à des …  Lire la suite

L'expression génique pendant la différentiation d'adipocytes est contrôlée par des évènements de transcription et post-transcription d'ARN. Il y a présentement un manque d'études sur les rôles des évènements post-transcriptionelles et de métabolisme d'ARN au cours du processus d'adipogenèse. Sam68 (Src associated substrate during mitosis of 68kDa) est impliqué dans plusieurs aspects de métabolisme d'ARN. Des souris ont été générées dont l'expression du gène Sam68 a été supprimé (Sam68-/-). Ces souris apparaissent plus maigres que les souris de phénotype sauvage, et ils sont protégés contre le développement de l'obésité. De plus, les cellules pré-adipocyte 3T3-L1, dont l'expression de Sam68 est réduite, …  Lire la suite

This thesis will examine a Vector Quantization-based system for speech enhancement. Key areas in this study will include the optimum size for the vector quantizer library and the distance measures used to index the vector quantizer library. In addition, the robustness of the overall enhancement process as a function on the vector quantizer training sequence (e.g., the number of speakers and the number of dissimilar phrases) will be explored. As speech enhancement is a diverse field, several other contemporary speech enhancement techniques will initially be examined in order to place the results of this study in a comparative light.  Lire la suite

Joos, Geza (Supervisor2)  Lire la suite

The study objectives were to measure the concentrations of albumin, prealbumin and transferrin in amniotic fluid (AF), and to establish if these concentrations were associated with infant birth weight (BW). At St Mary's Hospital (Montreal, Quebec), 294 AF samples were collected from mothers undergoing routine amniocentesis (12-19 weeks gestation). Exclusion criteria included subjects having gestational diabetes, multiple births or fetal genetic abnormalities. AF samples were analyzed by capillary electrophoresis (CE) at 190 nm. Analysis of variance and multiple linear regressions were performed. AF prealbumin could not be detected by CE. However, ANCOVA showed that transferrin was different among BW categories. …  Lire la suite

This thesis project consists of developing a hand-held, one-thumb input device small enough to be placed on gestural controllers and providing performers with a simple way to select between multiple options with few movements of a thumb. Most commercial input devices for the thumb make the assumption that buttons are the de facto standard. However, buttons are not always the best solution especially where space is very limited. This project explores a new approach to input design by analyzing the thumb's movements and designing a suitable input device that can track them. The design progression from the first to the …  Lire la suite

Stinner, Benjamin (Supervisor)  Lire la suite

Thomas, Aliki (Supervisor1)  Lire la suite

Dietary factors such as the consumption of tryptophan, the precursor of serotonin, or sugar, may play an important role in influencing alcohol-induced impairment. Study I used an amino acid diet to manipulate plasma tryptophan in male social drinkers in a 3 (supplemented, balanced, and depleted tryptophan) x 3 (alcohol, placebo, sober) design with 12 subjects per cell. A variety of mood, memory, and psychomotor performance measures were taken at baseline, five hours after amino acid ingestion, and after alcohol consumption. Strong alcohol effects were produced but no tryptophan, nor alcohol-tryptophan interaction effects were found. Study II examined the combined effects …  Lire la suite

Traditional methods to test integrated circuits (ICs) require enormous amount of memory, which make them increasingly expensive and unattractive. This thesis addresses this issue for scan-based designs by proposing a method to compress and decompress input test patterns. By storing the test patterns in a compressed format, the amount of memory required to test ICs can be reduced to manageable levels. The thesis describes the compression and decompression scheme in details. The proposed method relies on the insertion of a decompression unit on the chip. During test application, the patterns are decompressed by the decompression unit as they are applied. …  Lire la suite

Aspergillus fumigatus est un champignon omniprésent dans notre environnement. Lorsque des conidies de ce champignon sont inhalés par des individus immunosupprimés, celles-ci germent dans le parenchyme pulmonaire qu’elles envahissent provoquant des pneumonies nécrosantes léthales. L’un des facteurs de virulence principaux d’A. fumigatus est la production d’un exopolysaccharide cationique appelé galactosaminogalactan (GAG), un polymère nécessaire à la formation de son biofilm. La synthèse de GAG est prédite par l'activité d’un cluster de cinq gènes, dont l’un, ega3, est supposé être responsable de la production d’une glycoside hydrolase ancrée à la membrane plasmique d’A. fumigatus. Des études en spectrométrie de masse ont …  Lire la suite

This qualitative naturalistic research study investigated peer interaction and its relationship to the learning of Logo geometry concepts within an elementary school computer lab classroom environment. The work of four focal children (10-11 years old) and their partners was analyzed. The study looked at (1) the kind of working relationships which existed between the partners, (2) the verbal strategies used by the partners during their mathematics disagreement, and (3) the ways in which the talk between the partners and the strategies they used both contributed to their learning, and reflected their learning, of the geometry concepts (with an emphasis upon …  Lire la suite

Two studies of voluntary movement in Parkinson's disease were carried out. In the first study, both parkinsonians and age-matched controls performed unconstrained prehensile movements in which subjects produced reaching and grasping (hand opening/closing) movements under varying conditions of movement amplitude, speed and object size. The act of prehension requires the intersegmental coordination of limb transport and grasp trajectories. Although parkinsonians were slower overall than controls, patients and controls similarly adjusted the spatial and temporal characteristics of their limb movement and grasp in response to changes in task demands. All groups showed increases in the speed of limb transport, the speed …  Lire la suite

The aim of this work was to study proliferative growth of airway smooth muscle (ASM) cells from Fisher rats, a highly inbred strain known to have an increased amount of ASM in vivo, and airway hyperresponsiveness, when compared to control Lewis rats. Airway hyperresponsiveness is a hallmark of asthma, and ASM provides the contractile force which narrows or closes the airways during asthmatic episodes. Growth of ASM in asthma and animal models of asthma is well documented, and is likely to be a crucial determinant of an excessive airway response to contractile agonists. However, the mechanisms of ASM growth in …  Lire la suite

The goal of this thesis is to modify the traditional linear prediction (LP) analysis in such way that the fluctuations of the LP coefficients are reduced, while the pitch pulse shape evolves slowly. These modifications can lead to an increase in the coding efficiency and/or an improvement in the speech quality. Two different methods have been developed for this purpose. In the first approach we derive the LP parameters such that the glottal excitation model matches as closely as possible a target waveform. The latter contains slowly evolving pulses representing voiced speech excitation. The simulation results indicate that the target …  Lire la suite

Scavone, Gary (Supervisor2)  Lire la suite

Laptop performance---performance on a standard computer system without novel controllers, usually by a solo musician---is an increasingly common mode of live computer music. Its novelty is diminishing, however, and it is frequently described as being uninteresting. Laptop performance often lacks the sense of effort and active creation that we typically expect from live music, and exhibits little perceivable connection between the performer's actions and the resulting sound. Performance software designs tend to constrict the flow of control between the performer and the music, often leading artists to rely on prepared control sequences. Laptop performers become "pilots" of largely computerized processes, …  Lire la suite

L’importance et la quantité de phénomènes d’impacts de goutte sur des surfaces super-hydrophobes, qu’ils soient naturels ou industriels, font de ce sujet un vaste domaine d’étude. Dans de nombreux cas, il arrive que les surfaces perdent leurs propriétés de super-hydrophobie à la suite des impacts de gouttelettes, il est donc primordial d’avoir des surfaces super-hydrophobes robustes. La super-hydrophobie d’une surface dépend de sa chimie et de sa rugosité. Un liquide sur une surface rugueuse va former une interface air-liquide du fait de la présence d’air piégé dans les cavités. Afin de maintenir une bonne super-hydrophobie, le liquide ne doit pas …  Lire la suite

The efficacy of a lucid dream induction (LDI) technique was evaluated. The results indicated that, among previously non-lucid dreamers, a significantly greater proportion of subjects who had access to the technique reported a lucid dream. This group also reported more lucid dreams overall than the control group. For prior lucid dreamers, the technique was found to increase the number of such dreams reported, relative to baseline levels. The LDI technique was incorporated into a treatment procedure for recurrent nightmares. This treatment method was found to be effective in three individuals, although not all of them achieved a lucid dream state. …  Lire la suite

Six studies are presented whose combined goals were to investigate the relationship between the dimensions of repetition and negative affect in dreams, dream content measures, and measures of well-being. Study 1 presents the results of a content analysis of childhood and adult recurrent dreams. Study 2 showed that recurrent dreamers score lower on measures of well-being and report more negative dream content than both past-recurrent dreamers and non-recurrent dreamers. Study 3 showed that people who experience recurrent dream themes report low levels of well-being and negative dream content, but not to the extent shown by people with recurrent dreams. Underlying …  Lire la suite

Beverlea K Tallant (Supervisor2)  Lire la suite

Institutions, defined as rules, norms and strategies, play an important role in shaping socio-ecological interactions and determining human behavior. In Quebec, agro-environmental policies were introduced within the last 15 years to reduce the degrading effects of intensive agricultural production on land and water. However, the disturbance of water ecosystems remains a problem in agricultural areas in part due to producers' difficulties in complying with the present agro-environmental regulation. This research assesses the role of institutions in encouraging the compliance of hog farmers with Quebec's Règlement sur les exploitations agricoles (REA) in the Missiquoi Bay. This regulation is meant to reduce …  Lire la suite

The Canadian Charter of Rights and Freedoms has significantly changed the functions of the Canadian courts. Ever since its entrenchment in 1982, the third branch of government has enjoyed a powerful status in the Canadian polity. Countless Charter decisions, affecting the lives of all Canadians, have been rendered. The courts have been asked to rule on cruise missile testing, abortion, aboriginal rights, minority language rights and a whole range of other issues of a political, economic or social nature. Our political system, whose traditional foundations lay in the principle of parliamentary supremacy, has become one of constitutional supremacy. The new …  Lire la suite

And drown the wakeful anguish of the soul is a composition for chamber ensemble of thirteen performers. It is scored for flute/piccolo, clarinet, bass clarinet, two horns, percussion, piano, electric guitar, two violins, viola, cello and contrabass. The piece comprises thirteen variations on a musical idea which, although never explicitly stated, is reflected in every aspect of the work. The composed omnipresence of this idea is intended to impose homogeneity upon the variety of its manifestations.  Lire la suite

Nathalie Arbour (Internal/Cosupervisor2)  Lire la suite

A crucial requirement for the stepwise, continued growth of a brain tumor is the acquisition of a blood supply from the host, i.e. angiogenesis. The mechanisms of copper activity linked to neovascular and neoplastic growth are largely unknown. Copper ion was shown to be a cofactor for angiogenesis. We tested the effect of copper depletion achieved by a low copper diet and a copper chelator D-penicillamine, on the intracerebral growth of two experimental brain tumors. We developed in in vivo brain tumor model using the VX2 carcinoma. Implantation of 5 $ times$ 10$ sp5$ VX2 carcinoma cells into the parietal …  Lire la suite

Deschepper, Chirstian F. (Supervisor)  Lire la suite

En réponse au changement climatique, de nombreux chercheurs et décideurs du monde entier étudient des méthodes afin de définir des stratégies de réduction des gaz à effet de serre (GES) en lien avec la mobilité urbaine. Considérant que le secteur des transports est l’un des plus gros émetteurs de GES, la recherche dans ce domaine a suscité un vaste intérêt et s’est concentrée sur le développement de méthodes de quantification, l’identification des facteurs contribuant aux émissions, ainsi que la définition de stratégies et politiques de réduction. La présente recherche propose une méthode originale permettant d’estimer les émissions de GES causés …  Lire la suite

This thesis addresses the determinants of militia decision-making. Focussing on the Lebanese Forces (LF), the major Christian militia in Lebanon's Civil War, it analyses the motives which drove the LF to accept the Ta'if Accord--an acceptance that stands in stark contrast to its rejection of two earlier settlement blueprints, the Lausanne talks and the Tripartite Agreement. Steering away from the literature's focus on ideology as the prime mover of militias, the research explores other dimensions of militia decision-making, notably the impact of inter-communal power struggles, of the extra-communal balance of power, and of the international setting. Particular attention is given …  Lire la suite

When do militias---whose power, riches, and legitimacy depend on the continuation of civil wars---accept negotiated settlements? An unexplored and crucial dimension of militia decision-making is the process of militia institutionalization. Militias create institutions to improve their odds of winning the war and project legitimacy internally as well as externally. Militia institutions affect the strategic choice of decision-makers. They create financial and organizational interests that modify the preferences of the militia leadership. The modified preferences increase the win-set of militia leaders at the negotiating table. Militia institutions also change the decision-making context. Institutions unleash three dynamics that decrease a militia's ability …  Lire la suite

Cobb, Tom (Supervisor)  Lire la suite

The compound now known as cholesterol was first isolated by Poulletier de la Salle in 1770. The elucidation of the chemical structure of cholesterol was mainly due to the researches of Windaus and his associates, aided by the work of Wieland on the bile acids, and the studies of Suida and Mauthner on the derivatives of cholesterol. In 1919 Windaus arrived at a tentative formula which was changed, as a result of further work by Rosenheim, King, Dane, Diels and Gadke, and the final formulation as we know it today was decided upon in 1932.  Lire la suite

At the present time our understanding of rock behaviour under mining conditions is largely empirical. Limitations in this approach have been recognized and laboratory testing is gradually being introduced as another source of information. An adequate correlation of laboratory test results with field conditions has not been established but test results are being published, as in the report on mining practices at Elliot Lake (1)*, on the basis of their comparative value. This study aims at establishing some of the physical properties of an andesite rock by conducting tests on specimens cut from diamond drill core. The results may be …  Lire la suite

Pooling individual participant data from multiple studies can increase power to detect effects. However, when studies use different measures for the same constructs, harmonizing measures of that construct should precede statistical analysis on pooled data. A multiverse analysis conducts the desired analysis across all available datasets that could be obtained (e.g., using different definitions of constructs in harmonization), thus enabling the comparison of results across choice combinations. The present paper explores the impact of harmonization decisions using a case study. Data from four Canadian studies available through Research Advancement through Cohort Cataloguing and Harmonization (ReACH) are used to assess whether …  Lire la suite

We review Cartan's method for determining whether two G-structures are locally equivalent. This method is based on the reduction of the structure group to the identity, giving rise to a complete set of local invariants. There are several techniques such as group reduction, prolongation, involutivity test, absorbtion of torsion, and normalization needed in this procedure. Next we introduce the equivalence problem for first-order Lagrangians on the line. We apply this method to the solution of the equivalence problem for the first order Lagrangians under fiber-preserving transformations, point transformations, fiber-preserving transformations up to a divergence, and point transformations up to a …  Lire la suite

Cette thèse propose une approche basée sur l'apprentissage pour la modélisation et le contrôle de robots chirurgicaux souples, avec un focus sur les interventions percutanées. La robotique souple offre un potentiel transformateur dans les applications chirurgicales peu invasives grâce à sa flexibilité et son design bio-inspiré. Cette étude présente un réseau de neurones à autoencodeur bi-niveau pour modéliser et contrôler un robot souple inspiré de la colonne vertébrale, conçu pour les interventions intraluminales. Le système comprend un robot à câbles tendus imprimé en 3D avec un suivi en temps réel via un capteur électromagnétique et une micro-caméra.L’étude commence par compenser …  Lire la suite

Rodriguez, Rosario (Supervisor1)  Lire la suite

Brain wiring occurs during the development of the nervous system and ensures the formation of a highly complex network of intercommunicating neurons. For these circuits to be established, neurons form remarkably accurate connections with their target cells. The fruit fly visual system is an excellent model to study the formation and function of neural circuits, given the numerous architectural similarities between the visual system of the Drosophila and vertebrates at molecular, cellular, and network levels. Our lab has recently identified a novel mechanism by which Semaphorin-1a (Sema1a) reverse signaling upregulates axon-axon attraction in the developing Drosophila visual system. Sema1a promotes …  Lire la suite

Among the several methods used for the reproduction of an experimental arthritis in various species and strains of laboratory animals, the one induced by the injection of Freund adjuvant in rats seems to be the most attractive. Although no experimental arthritis satisfactorily resembles human rheumatoid arthritis, adjuvant polyarthritis appears to be highly promising because of its systemic manifestations, the clinical course, the migratory polyarthritis, the serological alterations, the roentgenologic changes and the histology. The disease is reproduced by a single subcutaneous injection of the rat’s tail with 0.8 mg. of dead mycobacterium butyricum suspended in 0.1 ml. paraffin oil.  Lire la suite

Waters from normal larvae of Aedes aegypti (L.) are highly attractive to ovipositing conspecific females, whereas waters from larvae infected with the entomopathogenic digenean parasite, Plagiorechis elegans Rudolphi, are rendered strongly repellent. The production of the repellent appears to be mediated by the degree of environmentally induced stress experienced by the larvae. Whereas waters from fully fed larvae were highly attractive as an oviposition site, these were rendered progressively less attractive, and eventually strongly repellent as the larvae were deprived of food over a period of 7 days. Crowding of the larvae elicited similar repellent effects as did close contact …  Lire la suite

Le domaine des métamatériaux, c’est-à-dire des matériaux qui possèdent des propriétés optiques utiles et qui n’existent pas à l’état actuel, a déjà mis en évidence l’utilité de nanostructures couplés à un plasmon en manipulation du rayonnement électromagnétique de façons novatrices. Les propriétés telle que l’indice de réfraction négatif sont postulées dans les systèmes incorporant des nanoparticules qui exhibent le couplage plasmonique. Présentement, l’enquête est limitée par les difficultés à produire ces structures avec les mesures nécessaires. L’incorporation de protéines de capside comme modèles pour l’auto-assemblage de constituants inorganiques aide dans la fabrication en parallèle de nanomatériaux avec des mesures qui …  Lire la suite

This thesis investigates the major areas in which 'Abd Allah ibn Fudi (d. 1245/1829) contributed to the Fulani Jihad which was initiated by his brother 'Uthman ibn Fudi in nineteenth century Hausaland.  Lire la suite