McGill University Thèses et mémoires par auteur commençant par B

The experimental work presented in this thesis explores, in anaesthetized and mid-collicular decerebrate, unanesthetized, cats, the properties of two components of the discharge of sympathetic nerves which are time-locked to the central respiratory cycle and are presumably generated within the central nervous system. One is the inspiration-synchronous burst, the other is a previously unknown late-expiratory burst. The properties of the inspiration-synchronous burst and its temporal relation to the phrenic nerve burst were studied under conditions in which the frequency of the latter was changed over a wide range by superior laryngeal nerve stimulation, by changes in ventilation frequency while the …  Read more

Jakobson, Dmitry (Supervisor1)  Read more

The electromagnetic field intensity and phase distribution in various receiving planes for a series of microwave solid dielectric lenses were investigated experimentally. The lenses were illuminated by a point source positioned at various distances off the principal axis of the system. Scans were made in both the E- and H-planes. Due to the finite size of the lens aperture the intensity distribution in the field of the lens must be described as a diffraction pattern. Although essentially the same for both the E- and H-planes of polarization, the lens pattern was found to deteriorate both in relative intensity and in …  Read more

During the past three decades the concept of a chemical bond has emerged from a vague, rather indefinite term into an entity with a precise and well-defined meaning. The physical properties of chemical bonds, their length and strength, have been the subject of much experimental and theoretical research. Bond length is a quantity which can be measured unambiguously with rather high precision. [...]  Read more

The reaction of nitrogen atoms with n-butane has been investigated at temperatures of 75 degrees C. and 250 degrees C., while the reaction with isobutene has been studied at temperatures of 100 degrees C. and 260 degrees C. Nitrogen atom flow was held constant while hydrocarbon flow rates were varied from 5 x 10-7 to 2 x 10-5 moles/sec. Hydrogen cyanide was the main product of both reactions. Smaller amounts of C2 hydrocarbons, mainly ethylene and acetylene, were produced in both reactions. Production of HCN, ethylene, and acetylene increased with increasing butane flow rates [...]  Read more

A study of novel ultrathin films is presented in two sections. The first section presents an investigation of several unconventional film-forming molecules at the air/water interface using the surface film balance apparatus. Strongly hydrophobic fullerenes (C$ sb{60}$ and C$ sb{70}$) were found to spread at the air/water interface to form Langmuir films of multilayer rather than monolayer thicknesses. The formation of these well-defined multilayers is independent of the initial surface density of the fullerene. The films adopt discrete thicknesses of 4-5 monolayer equivalents. The multilayer of the non-spherical C$ sb{70}$ exhibited a transition attributed to a reorientational process that was …  Read more

Hammond Reef is a low-grade (< 1 g/t or 1 ppm Au), disseminated gold deposit located in an anastomosing deformation corridor along the western margin of the 3.0 Ga Marmion tonalite gneiss, adjacent to the Marmion Shear Zone. The Marmion Shear Zone separates the Marmion gneiss and Finlayson Lake greenstone belt of the Mesoarchean Wabigoon subprovince. Most known Archean gold deposits are hosted in greenstone belt terranes. This places Hammond Reef in an under-explored environment with respect to gold exploration targets and warrants a detailed understanding of the deposit to elucidate the deformation history of the two adjoined terranes and …  Read more

L'attention visuelle décrit les mécanismes cognitifs qui filtrent les informations pertinentes des informations non-pertinentes pour le comportement. Les études Neurophysiologiques utilisant des enregistrements d'unités isole ont démontré l'existence d'un réseau de régions au niveau fronto-parietal impliqué dans l'allocation de l'attention. Cependant, d'important détails sur la façon dont l'ensemble des neurones simultanément actif supportant ce comportement restent pauvrement documenté. Lors de ce travail doctoral je vais examiner comment les ensembles de neurones au niveau du cortex préfrontal latéral du primate (CPFL) sous-tendent le filtre attentionnel sous différentes conditions comportementales. Premièrement, je démontre que l'ensemble de l'activité corrélée avec le comportement dans …  Read more

Smith, Donald L. (Supervisor1)  Read more

Soren Kierkegaard's final Attack upon Christendom marks the common culmination of three of the most important themes evident in his earlier, pseudonymous books, namely the 'Leap', the 'Offence' and 'Indirect Communication.' Modern critical scholarship tends to take one of two approaches. Either Attack is dismissed as a deviation from Kierkegaard's previous writing, or Attack is read without sufficient regard for its dependence upon what has come before. Both approaches make an aberration out of the final work. This thesis proposes that reading Attack in light of its proper relation to the pseudonymous writings offers a more complete picture of the …  Read more

One recent trend in medicine has been a redefinition of chronic illness. Whereas formerly chronic illness referred to a disease “which is progressive, steadily or with remissions, towards severe crippling or death,” it is now defined as a “long-term disease which might be cured if given adequate prolonged treatment or which might remit for long periods after treatment, enabling the patient to return to worth while living.” Coupled with this new perspective has been the development of the therapeutic community which calls for the treatment of the patient as a 'total individual' and not simply as a personified diagnosis.  Read more

Properties of sympathetic preganglionic neurones were examined in cat. Following horseradish peroxidase injection into the stellate ganglion, labelled neurones were in spinal segments C(,6)-T(,8) in regions of the intermediolateral nucleus, intermediate grey, central canal and ventral horn. Neurones located in the intermediolateral nucleus had a wide range of physiological properties, and, with the exception of basal activity, the properties studied failed to indicate subgroups. These neurones were also studied according to their sensitivities to substances implicated in synaptic transmission. (gamma)-Aminobutyric acid and glycine had inhibitory effects which were blocked by bicuculline and strychnine, respectively. Glutamate, aspartate and D-L- homocysteic acid …  Read more

Lewis, Eric (Supervisor2)  Read more

Prolonged inspection of high-contrast, black-and-white stimuli which are satiated with respect to direction of contour produces phenomenal impressions very different from otherwise similar stimuli which are varied with regard to contour direction. Reports of visual discomfort, apparent movement or shimmering of the lines, and evocation of colors are common (personal observations; MacKay, 1961). MacKay (1957, 1961) gives examples of such figures: fields of parallel lines, concentric circles, and concentric radial straight lines are among those with strongest effects. [...]  Read more

Ingram, Grant (Supervisor)  Read more

We review basic results in the field of finding extremal metrics for spectral invariants of the Laplacian on both graphs and manifolds. Special attention is given to the special case of the Klein bottle. The nececery theory is developed to produce the result of Jakobson et all [J-N-P] regarding lambda 1 on the Klein bottle. Using similar techniques, a new result is established in proving that there is only one extremal metric of a certain kind for lambda 2 on the Klein bottle.  Read more

Marandola, Fabrice (Internal/Cosupervisor2)  Read more

Dans cette thèse, je propose l'idée que le problème d'apprentissage de bonnes abstractions temporelles est intimement lié à un problème d'apprentissage de représentation que j'appelle "apprentissage temporel de représentation". Ce choix de terminologie vise à rappeler le fait que le temps est un aspect indissociable d'un système d'apprentissage plongé dans son expérience d'apprentissage avec son environnement. La réconciliation de la notion du temps avec celle de l'apprentissage mène à des solutions qui s'intègrent mieux dans un paradigme d'apprentissage continuel (Ring, 1991). Basé sur ce principe, je propose l'architecture option-critic pour construire des abstractions temporelles bout-en-bout (end-to-end) dans le cadre théorique …  Read more

L'identification automatique de goulots d'étranglement dans la structure de solution a joué un rôle important en apprentissage par renforcement hiérarchique au cours des dernières années. Bien que populaire, cette approche manque toujours de fondements théoriques adaptés. Ce mémoire tente de pallier ces lacunes en établissant des liens en théorie spectrale des graphes, espérant ainsi obtenir une meilleure compréhension des conditions garantissant son applicabilité. Une revue des efforts réalisés concernant les chaines de Markov presque complètement décomposable (NCD) permet de croire qu'elles pourraient être utiles au problème ici considéré. Un algorithme de découverte d'options motivé par la théorie spectrale des graphes …  Read more

The textures of two IF steels and a high purity $ alpha$-iron were determined after deformation in torsion over the temperature range 20-840$ sp circ$C. The three characteristic bcc torsion fibres are described in detail and the locations of some important ideal orientations are identified on the $ {110 }$ pole figure. At room temperature, these are the F(110)(001), J1 (011) (211), J2 (110) (112), D1 (112) (111), D2 (112) (111), E1 (011) (111) and E2 (011) (111). At elevated temperatures, the conditions were chosen so that dynamic recrystallization (DRX) took place in the ferrite and that static recrystallization was …  Read more

Nous proposons d'utiliser un algorithme basé sur la forme pour identifier les modèles dans l'imagerie par résonance magnétique dynamique de contraste (DCE-MRI) afin d'évaluer la perfusion tumorale ainsi que de délimiter automatiquement la région tumorale pertinente pour l'analyse. La DCE-IRM permet l'imagerie de la perfusion sanguine dans les tissus sains et dans les tumeurs. Des travaux antérieurs ont montré que le changement du taux de lavage de l'agent de contraste dans la tumeur entre un examen avant le traitement et après un cycle de chimiothérapie semblait être relié au résultat du traitement. La méthode proposée identifie la présence de courbes …  Read more

Contexte : L'auto-évaluation de la santé demande d'évaluer son propre état de santé en général et consiste en l'une des mesures les plus utilisées dans la recherche sur la santé de la population. Cette mesure a reçu de forts soutiens en tant que facteur indépendant prédicteur de mortalité et de morbidité. Nos connaissances demeurent limitées quant à notre compréhension de ce qui est exactement mesuré lorsqu'un individu évalue sa propre santé. Il est nécessaire de comprendre les caractéristiques de cette mesure chez les personnes atteintes de maladies chroniques. Objectifs : Dans un échantillon de la population Canadienne de personnes atteintes …  Read more

MATLAB est un langage de programmation dynamique populaire chez les scientifiques. L'utilisateur typique de MATLAB n'est pas un programmeur professionnel; MATLAB est principalement utilisé par des scientifiques, des ingénieurs et des étudiants, et doit sa popularité en grande mesure à sa syntaxe de haut niveau et à son éventail de librairies pour toutes sortes de domaines dans les sciences. Le manque d'expérience des programmeurs MATLAB, combiné à sa sémantique mal spécifiée et souvent contraire à l'intuition, mène à du code MATLAB qui est difficile à comprendre et maintenir. Dans cette thèse, nous présentons McIDE, un environnement de développement intégré pour …  Read more

In 1992, Algeria's government held its first ever democratic elections. With the Front Islamique du Salut poised to win the elections overwhelmingly, the Algerian military cancelled the democratic process and imposed military rule. Soon afterward, Algeria plunged into a civil war that claimed upward of 100,000 lives. Despite very significant popular support for the Islamist insurgency aiming to violently overthrow the Algerian government, the insurgency ultimately failed. Why? This paper will argue that while structural and actor-oriented approaches to understanding revolution are certainly important, they focus inadequate attention on contingencies that arise during a conflict, which in turn, affect structural …  Read more

A thorough investigation of a pulsed plasma x-ray source is presented with the intent of improving its design and maximizing its x-ray emission efficiency. In this approach a hollow gas column is puffed in the z-pinch diode by magnetically ionizing and compressing an inert gas in an annular plenum. This gas column is preionized by the radiation coming out from the plasma in the plenum and pinched by a fast electrical discharge. It is shown that the system can be improved considerably by modifying the gas puff design. Three gas puffs developed in this work are optimized for x-ray emission …  Read more

The research work presented in this thesis deals with carbon nanotubes (CNTs), an allotrope of carbon with a cylindrical structure consisting of a rolled up graphene sheet. CNTs are generally produced by the decomposition of a carbon source in the presence of a metal catalyst at elevated temperatures. CNTs have outstanding properties and have attracted immense attention in both industry and academia. However, the development of commercial applications of CNTs is slow due to limitations in the large scale production of CNTs and their high cost. Another limitation is the interface resistance generated by external catalyst nanoparticles used in traditional …  Read more

Fishing, like agriculture, is dependent on factors which are outside of man's control. The most important of these factors are: weather, related and nonrelated biological factors, and the resource. To some extent man has made it possible to circumvent these factors by weather forecasts, fishing season regulations, ever more sophisticated electronic equipment, and designs for swift boats. Still catch uncertainty in fishing, like yield uncertainty in agriculture, continues to harass the industry. [...]  Read more

Dasgupta, Kaberi (Internal/Supervisor)  Read more

Snell, Linda (Internal/Cosupervisor2)  Read more

We propose a notion of quantum control in a quantum programming language which permits the superposition of finitely many quantum operations without performing a measurement. This notion takes the form of a conditional construct similar to the "if" statement in classical programming languages. We show that adding such a quantum "if" statement to the QPLprogramming language simplifies the presentation of several quantum algorithms. This motivates the possibility of extending the denotational semantics of QPL to include this form of quantum alternation. We give a denotational semantics for this extension of QPL based on Kraus decompositions rather than on superoperators. Finally, …  Read more

The use of authority in casework often presents a problem for the social work practitioner because of the great emphasis in the profession on client self determination. At times, a discrepancy arises between this principle and what is therapeutically indicated for the client. Caseworkers are often faced with the conflict between creating an accepting and permissive atmosphere, and acting authoritatively in the best interests of the client. This presents a problem, but also a challenge. A clearer and fuller knowledge of some of the aspects of the use of authority in casework could well be of great assistance to the …  Read more

Man being born sentient is able to perceive the normative patterns which surround him in society. It is the contention of this thesis that individuals receive many common thought patterns in the process of socialization, but that their evaluation of these norms differ according to their dissimilar backgrounds. More specifically, the problem revolves around the ideas which a sample of high school pupils have about the occupational hierarchy and their evaluations of the occupations representing this hierarchy.  Read more

Hamel, Edith (Supervisor1)  Read more

Several mechanisms can lead to the reorganization of genomes during speciation, including centromere repositioning, new centromere emergence or other chromosomal rearrangements. Using a comparative karyotype approach, I determined that the vervet genome contains at least 12 evolutionary young centromere locations. To study the evolutionary dynamics of centromere formation, I identified and validated the alpha-satellite repeat as a centromere-specific marker in the vervet using comparative genomics, sequence analysis and hybridization screening. I developed criteria to infer the position of vervet bacterial artificial chromosome (BAC) inserts based on alpha-satellite monomer content. In a complementary approach, I demarcated the pericentromeric boundaries in human …  Read more

Transformed fatigue resistant skeletal muscle has been proposed as a potential power source for totally implantable ventricular assist systems (VAS). The goal of this study was to determine the optimal latissimus dorsi muscle (LDM) configuration capable of obtaining maximum power output. A device was designed to measure the power output and performance characteristics at varying levels of preload from each of four in situ configurations in Watts/kg of muscle(W/kg). Eight LDMs were acutely measured and revealed peak power output as follows: Sub-Dorsi (compliance chamber between LDM and chest wall): 8.3 +/- 1.6 W/kg; Circular (chamber in skeletal muscle ventricle): 16.4 …  Read more

Les monocouches auto-assemblees de n-alcanethiols sur des surfaces d'or, d'argent et de cuivre ont ete tres utilisees pour modeler les surfaces organiques et modifier les proprietes des surfaces metalliques. Cependant, a cause du caractere monomoleculaire du recouvrement et de la petite surface des substrats m'etalliques, la caracterisation des monocouches auto-assemblees n'est possible que si des techniques amplifiant le signal sont utilisees. Par consequent, les facteurs-cles tels que la nature de l'interaction metal-soufre, l'arrangement des chai nes hydrocarbonees et le diagramme de phase des especes adsorbees sur les surfaces metalliques restent a etre definis. La caracterisation des proprietes thermotropiques des monocouches …  Read more

La performance d’un système de reconnaissance vocale automatique (RVA) se dégrade considérablement lorsque la parole est corrompue par le bruit de fond. Dans plusieurs applications RVA, la présence de bruit de fond est inévitable. En général, les représentations caractéristiques en RVA sont calculées à partir de l’amplitude spectrale courte-durée du signal de parole, connu sous le nom de spectrogramme de parole. Le but de cette thèse est de développer un système RVA robuste au bruit en reconstruisant les spectrogrammes de parole corrompue par le bruit. Il s’agit ici d’un problème d’imputation de données dans le cadre de la théorie de …  Read more

A large number of technical issues are now available for the study of radioactive decay schemes. The complete investigation of decay schemes involves getting all information on nuclei and their states, such as spin, parity, and line widths. From this, conclusions as to regularities of nuclear structures can sometimes be drawn. To provide data for such investigations, two methods are widely used. One involves measurements of energy spectra of beta and gamma rays; the other consists of coincidence measurements from which the sequence of emissions from a nucleus can be determined.  Read more

The purpose of this thesis is to outline a framework of analysis for the study of foreign policy and to apply this framework to an analysis of the factors shaping the foreign policy of the People's Republic of China. There are two basic approaches to the study of foreign policy. The first, the historical approach, is essentially descriptive and is primarily concerned with improving our factual knowledge of the behaviour of particular states. The second, the anayltical approach, focuses upon state behaviour in general and attempts to formulate valid generalizations about state behaviour. Its ultimate goal is the elaboration of …  Read more