McGill University Thèses et mémoires par auteur commençant par B

In the course of preliminary studies aiming at defining the site of action of angiotensin, we have confirmed that infusion of this peptide, in large doses to rats, was producing a marked diuresis. Since this phenomenon was reproducible, we became interested in the compositionof the urine excreted under these conditions. [...]  Read more

Syntactic and semantic abilities were compared in 12 patients with mild to moderate dementia of the Alzheimer-Type (DAT) and matched controls. In Experiment 1A, performance on naming, word-picture matching, probe verification, and syntactic comprehension was assessed. Experiment 1B tested subjects' ability to use syntactic, semantic, and sentence contexts to choose the correct pronunciation of homographs and the correct spelling of homophones. Group data and individual patterns were reported. The main results revealed that: (1) all patients showed syntactic and semantic deficits; (2) patients were better able to use sentence contexts than syntactic or semantic contexts in isolation; syntax was not …  Read more

It is well known that when subjects with a disease are identified through a cross-sectional survey and then followed forward in time until either failure or censoring, their estimated survival function of the true survival function from onset are biased. This bias, which is caused by the sampling of prevalent rather than incident cases, is termed length bias if the onset time of the disease forms a stationary Poisson process. While authors have proposed different approaches to the analysis of length-biased survival data, there remain a number of issues that have not been fully addressed. The most, important of these …  Read more

In epidemiologic studies, prevalent cases with a disease are often identified through a cross-sectional study. These cases are then followed for a fixed period of time at the end of which the subjects will either have failed or have been censored. When interest lies in estimating the survival distribution, from onset, of subjects with the disease one must take into account that the survival times of the cases ascertained in such fashion are left truncated. When it is possible to assume that there has not been any epidemic of the disease over the past period of time that covers the …  Read more

Debonnel, Guy (Supervisor)  Read more

Le cancer de la peau est le cancer malin le plus fréquent chez les adultes. Son incidence mondiale augmente, surtout au niveau des régions anatomiques les plus exposées au soleil, telles que la tête et le cou. Le carcinome à cellules basales est le plus fréquent, représentant environ 80% des cancers de la peau de type non-mélanome, suivi du carcinome squameux et du carcinome sébacé.Le standard de diagnostic des cancers de la peau est l’excision chirurgicale de la lésion, suivi d’une analyse histopathologique. La nature délicate de la peau située dans la région péri-oculaire ainsi que la petite taille des …  Read more

Vulvar vestibulitis is a highly prevalent and underinvestigated pain syndrome that is considered the most common subtype of dyspareunia, or painful intercourse, in pre-menopausal women. The first chapter of this thesis consists of a critical review of the vulvar vestibulitis literature, covering descriptive, diagnostic, etiologic, and treatment aspects. This is followed by a retrospective study of 38 women, investigating the success of vestibulectomy, a frequently recommended medical treatment for vulvar vestibulitis. Results from structured telephone interviews pertaining to dyspareunia and sexual function show that 63.2% of participants experienced a significant improvement or a complete cure while 36.8% reported moderate to …  Read more

La diminution de l'étendue et de l'épaisseur de la glace de mer arctique a des implications significatives pour la productivité phytoplanctonique et leur floraison, avec de potentiels effets en cascade sur l'ensemble de la chaîne alimentaire marine et les communautés auto-suffisantes qui en dépendent. Dans cette étude, nous identifions comment le régime de glace de mer dans le Tallurutiup Imanga, l'une des régions les plus productives de l'Arctique, influence la croissance du phytoplancton ainsi que ses changements phénologiques. À cette fin, nous utilisons des observations satellitaires pour la concentration de glace de mer et des mesures de chlorophylle-a, des données …  Read more

Résumé Que le véritable substitut se lève: Une critique pluraliste des décisions partagées aux soins intensifs de nouveau-nés À l'unité des soins intensifs néonataux, les décisions portant sur le traitement des nouveau-nés impliquent une multitude d'influences normatives dont certaines peuvent entrer en compétition. Mettant à contribution le pluralisme juridique critique développé par Martha-Marie Kleinhans et Roderick Macdonald, cette thèse offre une analyse des interactions normatives qui émergent lorsque parents et personnel traitant se rencontrent au chevet d'un nouveau-né à l'état de santé précaire. En me basant sur le modèle de décision partagée favorisé par la Société Canadienne de Pédiatrie dans …  Read more

"Les effets de plusieurs concentrations (0, 0.1, 1, 10 et 100 mg!L) de chlorure de tributylétain (TBT) sur les transformations de l'azote, contrôlées par les microorganismes du sédiment ont été étudiés. Les tests de réduction de l'acétylène et de l'inhibition par l'acétylène ont servi respectivement d'indicateurs pour la fiXation de l'azote et pour la denitrification. Un effet d'inhibition du produit toxique, relié à la dose, fut observé sur les cultures de surnageant du sédiment, ce dernier obtenu par centrifugation du sédiment. Cet effet n'a pas été observé sur les cultures de sédiment entier. Après huit jours d'incubation, les cultures de …  Read more

Aux États-Unis, la polarisation affective croissante – la tendance des partisans de partis opposés à se détester les uns les autres – inquiète les politologues et attire beaucoup d'attention médiatique. Parmi les causes potentielles de cette montée de la polarisation affective figure le phénomène de tri social, par lequel les identités sociales des groupes partisans s’alignent parfaitement avec l'identification partisane. Dans ce mémoire, je réévalue les preuves concernant le lien entre le tri social et la polarisation affective en exploitant les données historiques du American National Election Studies. Je rapporte deux conclusions principales. Premièrement, l’augmentation du tri social au fil …  Read more

One way to achieve high data rate and bandwidth efficient wireless communications is to employ multiple transmit and receive antennas creating a Multiple-Input Multiple-Output (MIMO) system, combined with Linear Dispersion (LD) codes. Sphere Decoder (SD) is a low complexity Maximum Likelihood (ML) method of decoding LD codes. Using Subspace Matched Filtering principles, two complexity reducing front-ends to any variant of the SD, are developed. These two-stage decoders are designed to only have marginally worse performance than SD. Computer simulations confirm the lower complexity and close to ML performance of the two-stage decoders. For a two transmit and two receive antenna …  Read more

Dans son état actuel, l'étude de textures musicales formées à partir d'éléments indépendants superposés fait défaut de par son manque de précision terminologique. La notion de polytonalité reste elle-même sans consensus définitif, faisant l'objet de nombreuses controverses. Abordant ce problème langagier, j'effectue d'abord un survol du travail théorique actuel afin d'en déceler ses faiblesses. Je propose ensuite un modèle de différenciation de strates qui décrit la manière dont plusieurs couches texturales indépendantes peuvent se distinguer structurellement l'une de l'autre. Ce modèle fait usage de langage concis, précis et mis à jour. Dans un dernier chapitre, afin d'avancer son utilité en …  Read more

In their paper “Toward a Curse of Dimensionality Appropriate (CODA) Asymptotic Theory for Semi-Parametric Models”, Robins and Ritov (1997) introduced a missing data problem, with semiparametric model, for which it was said that the natural, sensible Bayesian approach failed, while the classical (frequentist) approach gave solutions with good asymptotic properties. We will explore their results after having studied the theory of missing data and semiparametric models. We will then show how a correct formulation of the problem using measure theory leads to natural Bayesian solutions with the same properties as the frequentist ones. We will finally give some simulation results …  Read more

We present PARVO, a computer vision system which addresses the problem of fast and generic recognition of unexpected 3D objects from single 2D views. After more than twenty years, the field of computer vision has still not produced any clear understanding of how this complex high-level visual capability is even possible. On the other hand, the human visual system is an existence proof that such a competence is attainable, as demonstrated informally by everyone's daily experience, and more formally, by the results of various psychological studies. Recently RBC, a new human image understanding theory, has been proposed on the basis …  Read more

Malaria is a parasitic (Plasmodium spp.) blood infection that affects over 300 million people annually and has applied strong selective pressure on the human genome in endemic areas. Several protein variants in erythrocyte and immune cells have been associated with protection against uncomplicated and severe disease including malarial anemia and cerebral malaria. We have used an unbiased forward genetic approach to compare inbred mice that display differential susceptibility to P. berghei ANKA infection as a means to study genetic determinants of experimental cerebral malaria. Susceptible C57BL/6 mice display early appearance of neurological symptoms and uniform lethality prior to day 12 …  Read more

Social Insurance has been defined as "The method of organized relief by which wage earners, or persons similarly situated, and their dependants and survivors, became entitled to specific pecuniary or other benefits, on the occurence of certain emergencies." It should be added that to be 'insurance', the method used must be on an actuarial basis, although it need not be contributory. There are four main emergencies which Social Insurance is designed to provide against, namely: industrial accidents, sickness, unemployment and an impecunious old age. I shall in this monograph deal, first, with the theoretical aspect of Social Insurance, and, secondly, …  Read more

X-ray mammography is currently the modality of choice for breast cancer screening. However, X-ray mammography cannot provide a positive diagnosis for cancer. A novel, dedicated breast imaging modality has been developed based on the principles of Positron Emission Tomography (PET). The Positron Emission Mammography (PEM) system is a sensitive, high resolution ($ sp sim2$ mm) breast scanner. PEM detects increased cell metabolism (indicating the presence of cancer) by imaging the distribution of tumour-specific metabolic radiotracers. The accurate co-registration of metabolic and X-ray breast images is important for localizing and characterizing suspicious lesions. Traditionally, registration between different imaging modalities has been …  Read more

The effects of aging on estrogen receptor (ER) levels and dynamics were assessed in hypothalamus (HYPO), pituitary (PIT), and uterus (UT) of female mice, 0-24 h following a bolus of estradiol. Nuclear ER levels were reduced and dynamics were altered in all tissues of aged mice. Age-related reductions of nuclear ER were associated with both losses of ER and reduced ability of cell nuclei to bind ER. Irrespective of age, ER dynamics differed among tissues. The duration of elevated nuclear ER was longest, and the rate of replenishment of cytosolic ER was fastest, in HYPO. Transient loss of ER was …  Read more

Fried, Gerald (Supervisor)  Read more

Ce mémoire examine l’histoire intellectuelle de la collaboration et de l'action collective dans la recherche sur l’IA et les systèmes multi-agents. S’appuyant sur des documents d’archives, des travaux de recherche en informatique, des comptes rendus de conférences, des rapports techniques et des publications journalistiques, il prend en compte les forces culturelles, institutionnelles et intellectuelles qui ont façonné les systèmes multi-agents et les équipes qui y ont travaillé. Le premier chapitre se penche sur l’histoire culturelle de SAIL et du SRI et considère la manière dont les mouvements de la contre-culture dans la région de la baie de San Francisco entre …  Read more

This thesis presents a new method of solution for the aerodynamics of finite-span wings, which overcomes the difficulties of the previous methods. The present method uses velocity singularities in the Trefftz plane (situated downstream at infinity) to derive the contributions in the solution of the circulation distribution caused by the changes in the spanwise variation of the wing chord and incidence. The new specific functions derived for these contributions contain both natural and forced symmetry and antisymmetry terms, and thus represent a correct mathematical modeling of the physical problem. The correct mathematical representation of these contributions leads to a highly …  Read more

Cette thèse présente une méthode innovatrice pour la planification chirurgicale en stimulation cérébrale profonde (SCP). Cette nouvelle technique combine différents contrastes d'imagerie par résonnance magnétique (IRM) – IRM pondérée en T1, IRM pondérée en susceptibilité magnétique, et angiographie par temps de vol (T1w-SWI-TOF) – ainsi qu'une analyse automatisée de trajectoires SCP pour optimiser l'évitement de structures cérébrales critiques, incluant les petits vaisseaux qui sont indétectables avec une acquisition conventionnelle par injection de gadolinium.Le premier objectif de cette thèse consiste à simplifier l'usage du protocole T1w-SWI-TOF avec la création d'un nouvel algorithme capable d'analyser automatiquement, en quelques secondes, des milliers de …  Read more

Two RNA trafficking cis sequences (A2RE-1 and A2RE-2) were identified in HIV-1 RNA. Their activity is assessed here during HIV-1 gene expression. Single point mutations in each A2RE reduced the levels of bound hnRNP A2, but also resulted in a marked accumulation of viral genomic RNA in the nucleus and a significant reduction in genomic RNA encapsidation in progeny virions, with the strongest phenotype observed for the A2RE-2 mutant. Immunofluorescence analyses revealed marked changes in viral gene expression patterns for pr55Gae and Vpr, as well as a significant reduction in Vpr incorporation levels. Viral infections were markedly compromised in the …  Read more

The relentless growth of internet traffic demand, along with the rising traction of bandwidth-intensive applications, is driving datacenters to seek higher transmission capacities. The transceiver market is primarily divided into two main architectures: intensity modulation direct detection (IMDD) transceivers, which operate in the O-band for short-reach intra-datacenter communications (under 10 km), and intensity and phase modulation with coherent detection (coherent) transceivers, which operate in the C-band for inter-datacenter and long-haul communications (typically beyond 40 km). The performance of transmission systems has traditionally been limited by the transmitter electro-optic modulator. Therefore, this thesis focuses on studying the architectures and system-level trade-offs …  Read more

Contexte : Les délires sont un élément caractéristique de la psychose et jouent un rôle important dans la conceptualisation et le diagnostic des troubles psychotiques. Malgré leur importance et leur pertinence clinique dans les troubles psychotiques, le rôle particulier que jouent les délires dans le pronostic de ces troubles n'est pas bien compris. Le contenu spécifique des différentes croyances délirantes et leur relation avec d'autres symptômes cliniques ou leur relation l’un avec l’autre ont fait l'objet d'encore moins d'attention. L'adoption récente de l'analyse de réseau en psychopathologie offre une nouvelle approche permettant de comprendre les interactions entre les symptômes au …  Read more

Bray, Garth M. (Supervisor)  Read more

Gracco, Vincent (Supervisor1)  Read more

Many claims have been made in recent years of the success of programmed instruction in increasing the rate of learning, or in decreasing the amount of time necessary for the mastery of facts, or in securing the retention of the knowledge of a given set of facts for a longer period of time. Sorne of the results claimed have depended upon the use of teaching machines, or other deviees; sorne have depended upon the use of programmed texts. In the early stages of the development of such teaching machines, and programmed texts, the programs constructed were produced by the psychologists …  Read more

This study examined the narratives and stories of 13 daughters of Jewish women Holocaust survivors. A qualitative multi-methodological integrative approach that incorporated feminist standpoint epistemologies and elements oF grounded theory was used. Mechanisms such as the use of an auditor and judges were utilized to address the researcher's reflexive stance and subjective frame. Participants' data were collected through semi-structured interviews. Interviews were subjected to extensive qualitative analyses and were compared to find recursive themes and sub-themes. The results oF this study indicated that Holocaust survivor mothers were conceptualized by their daughters as being either strong, challenged or both. Participants described …  Read more

This thesis presents a comprehensive study of the theoretical and computational modeling offluid dynamics in the context of sonic black holes, with a focus on the formation of acoustichorizons in nanoscale converging-diverging nozzles. A custom Python simulation frameworkbuilt around computational fluid dynamics library OpenFOAM was developed to replicatelaboratory conditions and explore the formation of acoustic horizons. The framework wasrigorously tested against known analytical solutions, including Poiseuille flow, ensuring accuracyand validity.Simulations of helium-4 flow at 77K were performed with a variety of nozzle geometries,including those used in previous high-pressure silicon nitride nanopore experiments.Remarkably, agreement with experimental geometries was found by matching …  Read more

Self-consistent field multiple scattering (SCF-MS) calculations have been performed on the aluminium trihalides, AlX$ sb3$ (X = F, Cl, Br, I) and their dimers, Al$ sb2$X$ sb6$ and on the large organometallic compounds diphenyltin(IV) dichloride and diphenyllead(IV) dichloride monomers and dimers. All these molecules have nuclear quadrupole resonance (n.q.r.) active nuclei and strong or weak intermolecular halogen interaction. In addition, diphenyltin(IV) dichloride has a Mossbauer active $ sp{119}$Sn nuclei to study the isomer shift and quadrupole splitting. Calculations used the Vosko-Wilk-Nusair(VWN) exchange-correlation potential in addition to Slater's X$ alpha$ exchange potential and also a quasi-relativistic wavefunction for the heavy nuclei …  Read more

Marino, Faleh Tamimi (Internal/Cosupervisor2)  Read more

Although a central etiology for Alzheimer disease (AD) has not yet been determined, support has amassed for the notion that oxidative stress may be involved in the pathogenesis of AD. The disruption of iron homeostasis and iron's excessive deposition in AD brain tissues has received increased attention due to the metal's capacity to promote the production of harmful free radicals. Several studies have recently examined whether DNA mutations involved in the iron overload disorder, hemochromatosis, pose an increased risk of acquiring AD. However, the small sample size and low generalizability of previous studies have warranted further investigation. We genotyped 213 …  Read more

Cette thèse a pour but l'étude de la franchise. Cet exposé a été divisé en deux parties. La première partie examine le dévéloppement historique de la relation de franchise et sa position dans l'économie comme une méthode de distribution. Par la suite, nous allons examiner la mesure à laquelle s'applique la Common Law ou le droit civil a la franchise. Par la suite, quelques problèmes specifiques tels fausse representation, fin et renouvellement et clauses de non-concurrence seront considerés. La seconde partie de cette étude concerne les ramificationsprincipales d'un franchiseur étranger qui opère au Canada, et aussi les développements législatifs que …  Read more

Behavioural models used to test antidepressants have shown that ligands that bind to sigma receptors possess "antidepressant-like" properties. The focus of this thesis has been to assess the action of various sigma ligands using in vivo extracellular recording in the dorsal raphe nucleus (DRN) and hippocampus. These two regions are heavily implicated in depression and in the mechanism of action of antidepressants. The hippocampus is also examined because it provides a model to distinguish sigma agonist and antagonist activity in the modulation of the NMDA response of CA 3 pyramidal neurons. In the DRN, sigma ligands produced a significant increase …  Read more

Seasonal fluctuations of industry, much more than is generally realized, play a major part in the total composite problem of unemployment and distress. The wide range of the Canadian climate, both in time and place, both regular and irregular, throughout the Dominion, has always exercised a restrictive influence on Canada's economic and commercial life. Seasonal fluctuations, particularly in agriculture, construction, forestry, traffic and trade, inevitably mean a seasonal rise and fall in the volume of employment, which in turn entails variations, in time and place, of purchasing power. [...]  Read more

Numerical simulations are invaluable in the development and understanding of magnetic resonance imaging (MRI) techniques. Motivated by the goal of understanding the behaviour of the functional MRI (fMRI) signal in brain tissue, this thesis employs a deterministic simulation technique in which the transverse magnetization and B0 inhomogeneity within a voxel are spatially discretized and the stochastic self-diffusion of water molecules is modelled as a Gaussian isotropic blurring of the transverse magnetization. While this simulation technique has existed since fMRI was in its infancy, its use has increased recently as investigators have attempted to quantitatively interpret the measured signal. Despite its …  Read more

Cette thèse présente de nouvelles modélisations théoriques et des études expérimentales de la biophysique du signal qui dépend du niveau de l'oxygénation du sang (BOLD), issu de l'imagerie par résonance magnétique fonctionnelle (IRMf), avec l'objectif central d'avancer l'IRMf calibré. L'IRMf calibré est une technique d'imagerie qui mesure les facteurs hémodynamiques et métaboliques changeants qui contribuent au signal BOLD et repose sur une procédure de calibration préliminaire qui utilise des tests de gaz hypercapniques ou hyperoxiques. Cependant, la nécessité d'un équipement spécialisé de livraison et de surveillance des gaz et des confins biophysiques associés aux tests de gaz, a empêché l'adoption …  Read more

Toth, John A. (Internal/Supervisor)  Read more

Stimuli which cause the accumulation of increased amounts of fat in the liver have interested both the clinician and the biochemist. To the former, they are of import, not only because fatty infiltration of the liver is found as a frequent pathological finding associated with various diseases, but also because this change has been shown to result in an impairment of hepatic function (129,380) and, if severe, to terminate in cirrhosis (79,83, 84,110,112). They are of interest to the latter as aids in the elucidation of fat metabolism, and therefore, indirectly, of other phases of metabolism. There is no doubt …  Read more

This investigation was primarily concerned with the interaction of the ('125)I-labeled human gonadotropins with testicular tissue from the human and from nonhuman primate species. The binding of the ('125)I-hFSH and ('125)I-hCG (or ('125)I-hLH) to a particulate fraction (P1) of the primate testis was highly specific. Gonadotropin binding was competitively displaced by the synthetic estrogens and an inhibitory factor present in testicular extracts (140,000 x g supernatant). The biochemical properties of the gonadotropin receptor (testicular) interaction of the different primate species were similar in most respects. All tissues had a greater FSH than LH binding capacity with an apparent dissociation constant …  Read more

At the beginning of the twentieth century, the primitive played a crucial role in the emerging European modernist aesthetic. While art historians have been exploring the role of primitivism in modern art for decades, this area of research has received little attention in musicology. In this dissertation I examine how primitivism is constructed in modern French culture as manifest in three of the most important avant-garde stage works of the first part of the century: the Ballets Russes's Le Sacre du printemps (1913) and Les Noces (1923), and the Ballets Suedois's La Creation du monde (1923). Relying on primary sources …  Read more

This study explored the ability of public students labelled emotionally disturbed toI school think divergently. The specific purpose was to discover whether these students would have greater difficulty than normal students on divergent thinking tasks. A second purpose was to evaluate the effects of an intervention course in creative problem-solving that was taught to a sample of students labelled emotionally disturbed. Subjects consisted of forty-five students from one of three public high schools under the Protestant School Board of Greater Montreal. Twenty-two of these subjects were labelled emotionally disturbed and the remaining twenty-three were classified as normal. […]  Read more

Three experiments investigated the hypothesis that high doses of methylphenidate (MPH) are particularly effective in enabling boys with Attention-Deficit Hyperactivity Disorder (ADHD) to regulate the allocafion of effort and persistence under high information processing demands. In Experiment 1, the performance of boys with ADHD, ages 7 to 13, was investigated on placebo and three dosages of MPH, on a visual-memory search (VMS) task across a wide range of processing loads. Accuracy increased with dosage in a linear fashion. Findings on reaction times (RTs) revealed, however, that MPH dosage had a differential effect depending on processing load. All doses of MPH …  Read more