McGill University Thèses et mémoires par auteur commençant par R

Une nouvelle forme de média, la réalité virtuelle (RV) et les vidéos 360◦ , ont renforcé l’immersion du public. L’attrait accru pour cette technologie a non seulement encouragé la prise en charge de la RV par les moteurs de jeu vidéo et d’autres plateformes matérielles, mais également le développement de technologies d’assemblage pour créer des vidéos 360◦ plus immersives. Un casque de réalité virtuelle est utilisé pour afficher un tel contenu et rendre possible une impression du relief en affichant une image légèrement différente à l’œil gauche et à l’œil droit. Ce format est connu sous le nom de stéréoscopie …  Read more

Large Language Models (LLMs) have transformed how we interact with and interpret digital information. Some LLMs are multi-modal, allowing text, image, audio, and video. This thesis uses a set of Music Information Retrieval (MIR) tasks to evaluate multi-modal LLMs for music understanding—interpreting high-level descriptors from audio. Five tasks are selected: genre classification, tempo estimation, singing voice detection, singer sex classification, and instrument classification. Each task involves resolving a text class or numerical value from an audio file. The process of uploading audio with an associated text prompt and parsing a result from the model's response is performed using Python scripts …  Read more

Biopeptides are synthesised as large pro-protein precursors that have to undergo proteolytic cleavage at positively charged amino acids (Lys and Arg) in order to become active. This cleavage is mediated by a family of subtilin/kexin related calcium dependent serine endoproteinases named prohormone convertases. The present thesis focuses on the endocrine member of the family named PC1/3. PC1/3 is expressed in the regulated secretory pathway of endocrine and neuroendocrine cells, where it was shown to activate various peptide hormones such as proopiomelanocortin (POMC), pro-insulin and pro-glucagon. PC1/3 is synthesized as a large precursor containing a signal peptide, a propeptide, a catalytic …  Read more

NADP+ and NADPH are involved in many biosynthetic pathways and signal transduction mechanisms. NAD kinase (NADK) is the only known enzyme that catalyzes the de novo synthesis of NADP+ from NAD+. In neutrophils, NADK plays an essential role to provide sufficient levels of NADPH to support a robust respiratory burst. Additionally, it would provide the NADP+ that is required for the synthesis of the potent granulocyte chemoattractant, 5-oxo-ETE. Despite the critical role of NADK, very little is known about its regulatory mechanisms in mammals. Activation of NADPH oxidase-2 (NOX-2) in neutrophils by stimulators of PKC, such as PMA, results in …  Read more

Caractères numériques sont la pièce maitresse des industries de production de films et de jeux vidéo. Cependant, et en dépit de plusieurs investissements et des progrès remarquables dans le domaine, la réalisation de réalisme physique des personnages animés reste difficile. Les approches actuelles sont soit des "kinematic workflows" hautement optimisées limités à suivre les données de capture de mouvement, ou sont basées sur des contrôleurs dynamiques offrant un contrôle limité sur le style qui souffrent de problèmes de robustesse. Il est donc d'un grand intérêt pour les chercheurs d'animation par ordinateur d'étudier et de développer des méthodes automatiques afin d'améliorer …  Read more

Pierre-Luc Girard-Lauriault (Supervisor1)  Read more

This thesis examines the propagation of small relative errors in poles in discrete-time domains $z, varepsilon={{z-1} over {T}}, z sp prime=z-1, w sp prime={2 over {T}}{{z-1} over{z+1}}$ and z = ${{z-1} over{Tz}},$ where T is the sampling period, to the continuous-time domain. By prescribing pole locations in the discrete-time domains or usable sampling periods in a continuous-time context, sensitivity specifications in time constant of a real pole, natural frequency, damping ratio and uncertain relative region of a complex pole can be achieved. It is shown in this thesis that the alternative discrete-time operators, $ varepsilon, z sp prime, w sp …  Read more

This thesis examines the characterization and performance evaluation of sampled-data control systems obtained with the digital redesign of continuous-time control systems. The first part of the characterization is concerned with the Plant Input Mapping (PIM) method which is the only digital redesign technique guaranteeing closed-loop stability provided the sampling period is nonpathological. Three modified PIM methods are proposed to solve the issues of reducing the order and the number of controllers present in a PIM-based control system. Furthermore, alternatives to the regular PIM method which utilize classical discretization techniques on the systems relating the reference input to the control input …  Read more

Mermelstein, Paul (Advisor)  Read more

MacGibbon, Brenda (Cosupervisor2)  Read more

Particularly in the health domain, humans thrive to reach an equilibrium between maximizing pleasure and minimizing harm. I propose that a cognitive strategy people employ to reach this equilibrium is the activation of Compensatory Health Beliefs (CHBs). CHBs are beliefs that the negative effects of an unhealthy behavior can be compensated for, or "neutralized," by engaging in another, healthy behavior. "I can eat this piece of cake now because I will exercise this evening" is an example of such beliefs. This thesis presents a theoretical framework which aims at explaining why people create CHBs and how they employ CHBs to …  Read more

Mujumdar, A. S. (Supervisor)  Read more

Experimental data have been measured at 23$ sp circ$C for reverse micelles formed by Aerosol-OT (AOT), and by dioctyldimethyl ammonium chloride (DODMAC), or bromide (DODMAB) in an organic phase in contact with an aqueous salt solution. The following studies in Winsor type II systems have been considered: (i) ion distribution in AOT and DODMAC reverse micellar systems, (ii) extraction of zwitterionic amino acids with AOT reverse micelles, (iii) extraction of proteins with DODMAC reverse micelles, (iv) water uptake of AOT, DODMAC and DODMAB reverse micelles. Depending on the study, the effects of the following variables were investigated: salt, amino acid …  Read more

Mineralized biological materials such as bone and seashells are made of relatively weak building blocks, yet they exhibit remarkable combinations of stiffness, strength and toughness. In particular, fracture toughness of these structures exceeds that of their components by several orders of magnitude. This performance can be largely explained by the "staggered microstructure" of these materials: stiff inclusions of high aspect ratio are laid parallel to each other with some overlap, and bonded by a softer, more ductile and tougher matrix. Under tensile stress the inclusions "slide" on one another, which generates large deformations and energy dissipation. This mechanism is predominant …  Read more

La pomme de terre, le membre le plus important sur le plan agricole de la famille des solanacées, souffre des effets de nombreuses maladies graves, parmi lesquelles la gale commune de la pomme de terre (CS), causée par la bactérie pathogène Streptomyces scabies, qui synthétise la phytotoxine de thaxtomine. Les bactéries bénéfiques qui s'établissent dans la zone racinaire, connues sous le nom de rhizobactéries favorisant la croissance des plantes (PGPR), jouent un rôle crucial dans l'amélioration du développement des plantes et la gestion des agents pathogènes des plantes. Par conséquent, les plusieurs séries d'expériences ont été menées pour formuler des …  Read more

Murray J. Fraser, (Supervisor)  Read more

A general review of the methods of hybrid formation is presented. The properties of an enzyme necessary for the purification of a DNA-RNA hybrid are outlined and the properties of the endonuclease of Neurospora crassa conidia is presented. The purified enzyme degrades single-stranded denatured DNA 50-60 times faster than native DNA and after ageing 6 -8 weeks, the enzyme degrades denatured DNA 200 times faster than native DNA. DNA-RNA hybrid is synthesized using denatured DNA as template and the four nucleoside triphosphates as substrate and then the endonuclease is used to purify the hybrid. Methylated albumin kieselguhr chromatography is used …  Read more

Dans la dernière décennie, la danse a été utilisée comme une forme de réhabilitation innovatrice pour différentes conditions médicales. Toutefois, il n'y a pas beaucoup de recherches documentées sur ces programmes de réhabilitation ayant comme objet la danse avec un partenaire. Les études portant sur l'utilisation du tango argentin prouvent cette faisabilité en tant que moyen de réhabilitation pour la maladie de Parkinson (MP). Le fait que la danse est une activité qui procure du plaisir aux participants renforce l'adhésion au programme. Le but de ce travail est de comprendre les avantages et la compréhension du tango argentin, une forme …  Read more

The hydrolysis of formamide, acetamide, propionamide and benzamide and of hydrocyanic acid, acetonitrile, propionitrile and cyanoacetic acid has been studied over a temperature range in concentrated hydrochloric acid solutions of concentration 1-1ON. Propionitrile hydrolysis was also investigated over a range of temperatures in concentrated sulphuric, hydrobromic and nitric acid solutions. The hydrolysis of propionitrile in sodium hydroxide solutions of concentration 0.3-4N has been studied. The products of thermal pyrolysis of acetonitrile and propionitrile were determined at different reaction times. The reaction of hydrogen atoms with propylene has been investigated by the Wood-Bonhoeffer method over the temperature range 30-250°C. The detection …  Read more

Surrealism is examined through its history and phenomenology. The frame of reference is shifted from the history of art to the history of religions; the premises of modern art historiography examined; and Surrealism placed within an interdisciplinary context. The conjunction between the Surreal and the sacred is developed through the phenomenological clues of the uncanny, the weird, and the irrational--popular perceptions of the Surreal. The Surreal is seen as the transition between the ordinary and the extra-ordinary: as the threshold of the sacred. The origins of the Surrealist impulse to "transform life" are traced to occultism, alchemy, and hermetic philosophy, …  Read more

MacKinnon, Kenneth J.  Read more

The Province of Quebec launched a province-wide reform of its schools and adult education centres in 1997 to respond to the exigencies of an increasingly multicultural population, and the requirements of a knowledge-based society. The reform aims to enhance democracy and citizenship. Based on the recent explosion in philosophical literature about varying models of democracy, and the concept of self advanced by each model, it is important to investigate what vision of democracy and concept of self is proposed for Quebec through this reform and what institutional measures are being adopted by the educational community to ensure its realization. This …  Read more

Some fifty years ago, Thorndike, (11), Small, (10), KLine, (5), and others, began systematically to study psychological aspects of animal behaviour. These early investigators used various kinds of mazes and problem boxes to describe the variables under examination. Since these pioneer attempts, new mazes and problem boxes have been designed, and a great deal of the research carried on in the field of comparative psychology has involved mazes of one type or another. A different “type of maze, designed by Hebb and Williams, (3), to evaluate rat intelligence, has provided the most recent improvement in animal testing apparatus. This thesis …  Read more

Peter Siegel (Supervisor2)  Read more

MacEachern, D. (Supervisor)  Read more

Even in ancient times it was noted that films of oil could affect the nature of water surfaces, for example, breaking up waves in stormy seas. But quantitative studies of films of oil on water were not really made until the middle of the 19th century when it was found (Quincke, 1869) (1), (Plateau, 1873) (2) that measurements of the surface tension of water were poorly reproducible. In 1890, Agnes Pockels (3) made an important contribution to the study of surface oil films. [...]  Read more

Dagher, Alain (Supervisor2)  Read more

In our present day democratic society certain important needs can best be met through group activities. These include the need for social contacts, for cultural expression, for the organization of action, and for group concern for the common good. The group plays a vital role in meeting these needs and in the preservation of our democracy. It is the practical training ground where people learn both the form and the practice of democratic living. Miss Coyle has pointed out that, “Many of them (groups) are permeated with the basic homespun relations of mutual respect, orderly procedures and common consent out …  Read more

Luchins, A. S.  Read more

Luchins, A. S. (Supervisor)  Read more

An enzyme that catalyzed the terminal step in GM(,1) ganglioside biosynthesis was demonstrated in rat brain and rat liver microsomal preparations. This galactosyltransferase enzyme could be solubilized from the Golgi fraction of rat liver homogenates. Anion exchange chromatography resolved two distinct enzymes with activity toward GM(,2) ganglioside. These two activities could be distinguished by such properties as pH optima, detergent requirements, and isoelectric points. The two enzymes had similar molecular weights and cation requirements. Extensive characterization of the acceptor specificities of galactosyltransferase enzymes present in solubilized Golgi preparations led to the identification of five enzyme reactions. Two activities were identified …  Read more

Cognitive training paradigms constitute a budding field in both research and the commercial market. Engulfed in hype, computerized training programs are particularly enticing in the "Informatics Era" and have fostered the development of increasingly complex programs aiming to improve cognitive function. With the promise of enhancing skills such as attention and memory, cognitive training programs appeal particularly to atypically developing individuals as a non-pharmaceutical alternative to treatment. Such claims have led both professionals and laypersons to question the effectiveness of commercially-available products. In our critical review, we investigate the potential benefits of various cognitive training paradigms and evaluate the evidence …  Read more

The hypothalamic supraoptic nucleus (SON) in the rat contains neurons that synthesize either vasopressin (VP) or oxytocin (OT) and receives inputs from medullary nuclei. While VP neurons receive inputs from noradrenergic cells in the caudal ventrolateral medulla (cVLM), no pathway from medullary nuclei had yet been described that would account for the excitation of OT neurons produced by gastric stimuli. Retrograde tracer experiments revealed a direct pathway from the nucleus tractus solitarius (NTS) to the SON, made up of axons arising from noradrenergic and non-noradrenergic neurons. Immunocytochemistry experiments identified putative transmitter substances in non-noradrenergic neurons as inhibin-$ beta$ and somatostatin-28 …  Read more

A study was conducted for two growing seasons in northeastern Syria to evaluate the effect of N and P fertilizers and previous crops--i.e. vetch (Vicia sativa L.), barley (Hordeum vulgare L. cv. Beecher) or fallow--on water consumption, development, growth and yields of barley in a semi-arid, Mediterranean-type climate. The two seasons contrasted in rainfall and temperature which affected soil N, water use and yields. Fertilizer addition and residual P were the major determinants in barley yield increases. Rotation effects were significant only when fertilizers were added. Fallowing was an inefficient way of storing water, but stored water was used most …  Read more

Cytochrome b(,5) is an integral membrane protein of the endoplasmic reticulum of the hepatocyte. Previous work by the groups of Ozols and Strittmatter has determined the primary sequence and the orientation of the molecule. It is embedded on the cytoplasmic face of microsomal membranes via a hydrophobic 40 amino acid long "tail" at the carboxy terminus. The synthesis of this protein is assigned to the free polyribosome population of rat hepatocytes, and the experimental documentation of this assignment is reported. Free and membrane-bound polyribosomes were separated by a modification of the method of Ramsey and Steele (1976) and characterized by …  Read more