McGill University Thèses et mémoires par auteur commençant par O

The subject of this thesis is the attenuation of disturbances by feedback in the presence of large plant uncertainty in MIMO systems. Some relevant optimizations are formulated in an H$ sp infty$ setting, and are shown to reduce to a 'two-disc' mixed sensitivity problem. Despite its basic nature, the two-disc problem has not previously been solved, although approximations to it have been proposed. It is shown, by means of examples, that such approximations may involve large errors, highlighting the need for an accurate theory. An accurate theory of the two-disc problem is achieved by expressing the two-disc problem as a …  Lire la suite

Some species of sundew (Drosera spp.), harvested from the wild for use in homeopathic cold remedies, are now endangered. This research consisted of two experiments in hydroponic production of sundew. The first investigated the effects of four nitrogen (N) fertilization levels (0.0, 5.1, 25.5 or 51.0 mg/L added N) and three harvest methods (after two months, four months, and sequential harvest at two and four months) on the growth of Drosera adelae (F. Muell.). In addition, the effect of N on the production of a medicinal active ingredient in D. adelae was examined. The second experiment investigated effects of the …  Lire la suite

Limperopoulos, Catherine (Internal/Supervisor)  Lire la suite

Antioxidant activity was measured in 14 plant species incorporated in more than 30% of Tibetan medicines used for cardiovascular disease and related symptoms according to indigenous pharmacopoeias. The study was undertaken in order to explore possible dietary/medicinal elements which may contribute to the reportedly low incidence of cardiovascular disease among Tibetan highlanders despite high hematocrit levels and a high saturated fat/low fruit and vegetable diet. Extracts of Terminalia chebula, Syzygium aromaticum, Aquilaria agallocha, Santalum album, Amomum subulatum, Justicia adhatoda and Myristica fragrans were strong scavengers of the 1,1 diphenyl-2-picryl-hydrazyl (DPPH) radical (P < 0.05). Cu2+-catalyzed low-density lipoprotein (LDL) oxidation was …  Lire la suite

Simplification of diets and reduced consumption of traditional foods and medicines play an important role in the increased prevalence of noncommunicable disease (NCD) in developing countries undergoing the nutrition transition. Empirical evidence on the consequences of reduced dietary diversity and exposure to functional dietary elements is sorely lacking in the literature. To address this, a food frequency and ethnomedical survey of 365 participants stratified according to age, gender and area of residence was conducted in coastal Papua New Guinea (PNG), and anthropometry, blood pressure and fasting blood glucose (FBG) recorded. Our results support the hypothesis that reduced food variety, especially …  Lire la suite

This thesis presents a description and interpretation of the geology of an area of approximately 225 square miles, located in the extreme northern part of the province of Quebec and covering part of the so-called "Labrador Trough". It is based on field mapping done during the summer of 1952 for Fenimore lron Mines Limited and laboratory investigation at McGill University during 1952 and 1953.  Lire la suite

This work is being attempted to study the type, genesis and commercial possibilities of a series of very large bodies of massive pure quartz in the Watshishou Knoll area. The writer spent eight days during the fall of 1949 mapping the area on a scale of 1138 feet to the inch. Specimens were collected,and were subsequently studied in the laboratories of McGill University. [...]  Lire la suite

This study used a broad theoretical framework encompassing an ecosystem approach to HIV-1/AIDS that investigated: local knowledge of HIV-1/AIDS and other sexually transmitted infections (STIs); local knowledge of the nexus between HIV-1/AIDS and tuberculosis on one hand, and other STIs on the other; the factors of the ecosystem that influence the contraction and transmission of HIV-1; and the local responses to HIV-1/AIDS among the Turkana of Lodwar Township. The study found that, according to the Turkana's local knowledge of HIV-1/AIDS, other sexually transmitted infections, and tuberculosis, these infections are largely contagious, and are attributed to impersonal and natural causes. In …  Lire la suite

Birth asphyxia is one of the major cause of mortality and morbidity of newborns worldwide. Therapeutic hypothermia is the current treatment in term asphyxiated newborns in order to try preventing the development of brain injury. Induced hypothermia is believed to work by decreasing brain temperature and thus reducing baseline brain's metabolism and energy demand. Despite this treatment, some of the asphyxiated newborns still develop brain injury. The purpose of this thesis was to monitor the brain and its development in the asphyxiated term newborns treated with hypothermia, during the first month of life. To aim this goal, multi-modal magnetic resonance …  Lire la suite

After the Second World War, calls for world citizenship were countered by increased demands for national loyalty and patriotism. Many newly formed or independent states configured definitions of citizenship along ideological, religious, or non-territorial lines. By contrast, the Charter of the United Nations (1945) and the Universal Declaration of Human Rights (1948) propounded global allegiances and affiliations. The conflict between international and national allegiance is inherent to postwar global structures and their subjects. In the context of totalitarianism and other forms of colonialism, allegiance to the state constitutes a breach of the civil contract: the implicit endorsement of human and …  Lire la suite

Les modifications de la coordination motrice induites par la fatigue peuvent fortement affecter la performance en natation, en particulier chez les athlètes présentant des déficiences physiques. Une étude antérieure a démontré de façon quantitative des changements de variabilité de dans les gestes de natation dans la direction médiolatérale; cependant, aucune étude n’a auparavant décrit ces changements dans la direction vers l’avant.Six para-nageurs classés internationalement (S3 à S14) ont participé à une étude transversale. Les longueurs des segments du membre supérieur ont été mesurées manuellement et un indice de symétrie des membres (LSI) a été calculé. Un capteur inertiel (IMU) a …  Lire la suite

Like other countries which have only recently emerged from British colonial rule, for example, India and Ceylon, or are on the verge of attaining self-government, Kenya has had to face the task of choosing an official language. In her case the choice has been complicated by the prominence of two languages, namely, Swahili and English. Swahili, a Bantu-based language, is widely spoken and understood among the country’s population, whose languages belong mainly to the Bantu family of languages. It is estimated that some 7,000,000 people throughout East Africa speak Swahili as their native language.  Lire la suite

The focus of this thesis was on the economic feasibility of three food processing projects. They involved freezing of pork loin and fish using cryogenic freezing and stored at $-$18, $-$12 and $-$7$ sp circ$C, and modified atmosphere packaging (MAP) of pork loin using a combination of nitrogen and carbon dioxide gases, chitosan dip and stored at 5, 10, and 15$ sp circ$C. A production plan with similar layout and capacity was adopted for the Montreal area. The benefit-cost analysis (BCA) of each project was carried out assuming that each plant operated approximately 2000 hours per annum at full capacity. …  Lire la suite

Les copolymères de styrène/acrylonitrile (SAN) avec des excellente fidélité en bout de chaîne et des faible polydispersité Mw/Mn (1,10 - 1,30) ont été synthétisés par polymérisation des nitroxydes (NMP) dans une solution de diméthylformamide (DMF) avec d'ester de succinimidyle (NHS) groupe terminal de l'soi-disant SG1 résidus nitroxyde. Ces copolymères ont été stabilisée thermiquement par élimination du groupe N-tert-butyl-N-[1-diéthylphosphono-(2,2-diméthylpropyl) nitroxyde] (SG1), et ensuite modifiée pour former une amine primaire à fonctionnalité en bout de chaine des copolymères (SAN-NH2) . Réactions de couplage homogènes et transformée de Fourier spectroscopie infrarouge (FTIR) a indiqué que le groupe amine a effectivement été placé en …  Lire la suite

Straub, David (Supervisor)  Lire la suite

Cadre: La tuberculose (TB) demeure une des causes les plus importantes de mortalité, responsable de près de 2 millions de décès par année, dans le monde. La stratégie établie de contrôle de la TB (traitement directement observé, courte période (DOTS)) a réussi à accroître l'accès au diagnostique et au traitement de base mais n'aborde pas adéquatement les défis reliés au contrôle de la TB tel que la pharmacorésistance. Plusieurs technologies novatrices sont développées et évaluées dans le but d'améliorer le contrôle global la TB. Les modèles de simulation par ordinateur peuvent aider les décisionnaires politiques à prioriser les interventions. L'objectif …  Lire la suite

The level structures of ('94)Ru, ('90)Mo, ('88)Zr, ('89)Mo and ('89)Nb have been studied via the decay of two isomers of ('94)Rh, two of ('90)Tc, two of ('88)Nb, one of ('89)Tc and one of ('89)Mo, respectively. These nuclides were produced via the proton bombardment of isotopically-enriched ('96)Ru and ('92)Mo as well as naturally-occurring Zr. Using gamma and beta spectroscopy techniques, detailed level schemes have been produced. High-spin states in ('89)Nb, ('88)Zr and ('88)Nb have been studied with in-beam gamma-ray spectroscopy techniques. These nuclides were produced with alpha particle-induced reactions on ('89)Y. A neutron-multiplicity experiment was used to identify the nucleus to …  Lire la suite

This thesis seeks to contribute to solving the debate about the framework of rules and institutions applicable to public utility sectors, by adopting both economic theories, such as natural monopoly, network effects, and public goods, and practical analysis of the telecommunications sectors for both Australia and the United States. Governments must reevaluate the framework regulating public utility sectors whenever rapid technological advancements occur. This thesis argues that the antitrust authority better enforces competition rules, and that the sector-specific authority better enforces technical and universal service rules. The justification of the special competition rule concerning bottleneck facilities access should be limited. …  Lire la suite

Peter Henry Radziszewski (Internal/Supervisor)  Lire la suite

Perfluoroalkyl and Polyfluoroalkyl substances (PFAS) are anthropogenic chemicals with unique properties and wide applications in industrial and consumer products. However, studies have shown that the once highly valued PFAS are persistent pollutants, ubiquitous in the environment, and are developmental and reproductive toxins. To meet the stringent drinking water guidelines for PFAS, technologies that can destroy PFAS are urgently sought for. As multiple carbon-fluorine bonds render many conventional destruction processes ineffective, advanced oxidation-based treatment methods are some of the very promising methods for the destruction of PFAS in contaminated environmental matrices. Nevertheless, if effective oxidation-based treatment methods are to be developed, …  Lire la suite

The thesis aims at studying the background, the process of development and the effect of the Lanase movement upon the Yoruba Islam. The thesis aims further to study the various problems which the movement is facing because of the changes taking place in Nigeria today. Among these are the rise of Nationalism, secular education, religious liberalism and female emancipation struggles.  Lire la suite

Warkentin, B. (Supervisor)  Lire la suite

The growing prevalence of dementia in Nigeria intensifies caregiving demands on families operating within fragile health and social support systems marked by limited dementia-specific services, scarce formal resources, and persistent stigma. However, dominant dementia care paradigms remain largely anchored in Eurocentric frameworks that inadequately reflect African sociocultural realities. This reliance on the Western model risks obscuring contextually grounded understandings of dementia and care. Despite this, little research has interrogated dementia caregiving through African epistemologies or how Yoruba families navigate formal, informal, and spiritually embedded support systems amid structural constraints.The overall aim of this thesis is to advance African-centred dementia care …  Lire la suite

Electoral systems influence politics in multiethnic societies and often incite multiethnic conflict. This study explores the reasons underlying variations in the effect of different electoral systems on political stability and ethnic conflict in Tanzania and Kenya. More specifically, at the most general analytical level my study found that in Kenya, the ‘First-Past-The-Post’ (FPTP) electoral system worsens ethnic tensions because political success depends on ethnic mobilization, which marginalizes smaller ethnic groups. In contrast, Tanzania's electoral system combines proportional representation and FPTP to generate more inclusivity and to eliminate ethnic tensions accruing from cross-ethnic representation. Furthermore, to explain changes in patterns of …  Lire la suite

In order to clone the DNA repair gene of Aspergillus nidulans, uvsF$ sp-$ pyrG$ sp-$ strains were transformed with a genomic library in a plasmid vector that carried the pyr-4 gene of Neurospora which complements pyrG mutants of Aspergillus. Out of the several transformants obtained, four were like wild type. For rescuing plasmids, transformant DNA was digested with Bg/II and self ligated, and used for transformation of E. coli. Two types of plasmids were obtained; these two had a region in common ($<$1.0 kb) that was not a simple overlap and gave evidence for rearrangements. Surprisingly, only the plasmids with …  Lire la suite

Although extreme poverty has decreased in the last decades, we are a long way from eradicating global poverty. Similarly, the world has seen a considerable decrease in global inequality due to recent developments in emerging economies, but overall inequality between nations has risen in the last decades. International tax law may have a relevant role in improving or worsening global inequality. Extensive research has shown that the present international tax system was designed in a way that tends to benefit high-income economies. However, there has been no significant discussion about whether and how international tax law rules should be changed …  Lire la suite

Weight reduction in vehicles has important benefits of fuel economy and reduction in greenhouse gas emissions as well as improved vehicle performance. The current material for the diesel-engine block/head is mostly ductile iron and replacing it with aluminum alloys would result in very effective weight reduction (30-40%). Current commercial cast aluminum alloys, however, soften at engine operating temperatures exceeding 200°C and would cause early fracture in the diesel engine. Two new alloys derived from the commercial alloy (A356) are described in terms of microstructure, creep, aging behavior and tensile properties at elevated temperatures. The alloy containing both peritectic (Cr, Zr …  Lire la suite

The growing use of synthetic chemicals to combat insects of economic importance to man has led to the discovery and wide recognition of changes in the nature of insect populations and of subsequent control failures. Changes which result in inadequate control when an insecticide dosage which was formerly effective is employed are termed insecticidal resistance. Major review papers (Brown 1958, Crow 1960, Metcalf 1955) all conclude that resistance is a result of natural selection taking place with such rapidity that the worker is able to observe the evolutionary processes. Smith (1941) was one of the first workers to call attention …  Lire la suite

Cette thèse examine la représentation et l'acquisition de l'accent lexical en turc. Deux propositions principales sont avancées, la première concernant la phonologie théorique et la seconde, l'acquisition en langue seconde (L2) de la prosodie lexicale. Il est d'abord proposé que la présence ou l'absence d'un pied prosodique est paramétrique. Contrairement à ce qui est suggéré dans plusieurs travaux (Selkirk 1995, Vogel 2009), il est proposé dans cette thèse que le pied n'est pas un constituant prosodique universel. Au contraire, certaines langues, dont le turc et le français, ne possèdent pas de pied. Plusieurs arguments en faveur de cette position provenant …  Lire la suite

This study investigates the supranational policy engagement of Turkish migrant associations in France and Germany in EU immigration policy process from a comparative perspective. It seeks the answer to the following question: What explains similarities and differences in terms of forms and levels of participation by migrant associations in different national contexts as they engage in the EU immigration policy process? In addressing this question, it analyzes the forms and levels of migrants' supranational engagement by focusing on the combined impact of emerging macro-level political opportunity structures (EU institutional context and EU) and micro-level (collective action problems of nationally organized …  Lire la suite

L'industrie minière est caractérisée par des risques techniques et financiers élevés. Tout d'abord, la quantité de minerai dans un gisement ne peut pas être calculée, du moins au stade de la faisabilité, en raison de la rareté des données et de l'hétérogénéité de la qualité. Dans l'approche standard, toutes les décisions concernant une opération minière sont prises à l'aide d'estimations ou de simulations, qui ajoutent un risque à une opération. En outre, les prix des produits de base fluctuent considérablement sur le marché. Comme on l'a vu récemment, de graves baisses de prix peuvent se produire et obliger les sociétés …  Lire la suite

Magnesium additions to aluminum enhance strength and hardness, lowering density, and improve corrosion resistance. However, during melting and casting processes, significant amounts of magnesium are lost due to selective oxidation. Preventing these losses would reduce the production cost and improve the quality of the final product. The effects of various levels of strontium addition on the oxidation behaviour of aluminum-magnesium alloy melts were investigated by monitoring sample weight gains with time using a thermogravimetric balance at 750°C. Sample cross-sections have been examined in detail using Hitachi S-4700 Field Emission Gun Scanning Electron Microscope, and phases formed on the oxide layer …  Lire la suite

In this research, we review the Petri net formalism as well as the resolution methods involved in graphical simulation and performance analysis and introduce generic concepts that enable users to visualize the results of dynamic analysis through a consistent user interface. From the user's point of view, our goal is to facilitate the usage of dynamic analysis and ease the interpretability of its results. This is achieved by hiding complex dynamic analysis resolution methods behind an attractive user interface layer, while providing the user with full control over both the methods' execution and the display of their results. From the …  Lire la suite

Le stress oxydatif, qui est un débalancement entre la production d’espèces réactives de l’oxygène (ROS) et les défenses antioxydantes, est associé à 30-80% des cas d’infertilité chez l’homme. La Peroxiredoxin Bifonctionnelle (PRDX6) ne protège pas seulement les spermatozoïdes des dommages oxydatifs en détoxifiant les ROS, elle joue également un rôle dans le maintien de l’homéostasie des phospholipides cellulaires en modulant le signalement redox qui permet aux spermatozoïdes d’acquérir leur pouvoir fécondant. Nous avons démontré précédemment que les spermatozoïdes d’hommes infertiles ont un niveau plus faible de PRDX6 associé à une faible motilité des spermatozoïdes et une augmentation de dommages à …  Lire la suite

Alzheimer’s Disease (AD) is a progressive neurodegenerative disease characterized by the accumulation of abnormal proteins, neurodegeneration, and cognitive decline. Amyloid-beta (Aβ) and tau are the main pathological hallmarks of AD, and they start to accumulate up to 20 years before the onset of clinical symptoms. While tau deposition may initiate independently and even before Aβ accumulation, it is hypothesized that Aβ pathology is required for tau to propagate outside of the medial temporal lobe and start the pathological cascade leading to AD dementia and is, therefore, an ideal target for clinical trials. Despite this hypothesis, most clinical trials that targeted …  Lire la suite

This thesis comprises three interconnected projects addressing challenges in multi-label classification and temporal graph learning. In the first project, we tackle the challenge of modelling label dependencies in multi-label classification. We introduce a graph-based dependency module that is capable of modeling multiple types of relations. The module can be incorporated in embedding-based multi-label classification methods, leading to Relation Guided Message Passing (RGMP), a novel multi-label classification approach. We demonstrate via experiments that the proposed method achieves superior or comparable performance to state-of-the-art methods across all studied datasets, without imposing substantial additional model complexity or computational overhead. This emphasizes the importance …  Lire la suite

In this thesis, changes in the regulation of the transcription factor activator protein-1 (AP-1) were used as markers to study altered gene expression in the conceptus after oxidative stress. Both experimental and clinical studies implicate oxidative stress in embryo malformation. In the conceptus, the tripeptide, glutathione, protects against oxidative stress. It exists in oxidised (GSSG) and reduced (GSH) forms, and the GSSG:GSH ratio is an important measure of oxidative stress. At the initiation of rat whole embryo culture we noted a transient increase in the GSSG:GSH ratio. This was associated with an increased AP-1 DNA binding activity and increased expression …  Lire la suite