McGill University Thèses et mémoires par auteur commençant par R

Oligomerization of membrane proteins in response to external stimulation is a common event in cell signalling for generating functional diversity. In the case of the heptahelical receptor (HHR) superfamily, the traditional view has been that these receptors function as monomers, although a number of recent studies have suggested that this class of membrane proteins may exist as dimers or higher order oligomers, and play an important role in signalling. We addressed this question using as a model the somatostatin receptor (SSTR) family, which comprises five molecular subtypes (SSTR1--5). Receptors were expressed at physiological levels in CHO-K1 cells and characterized pharmacologically …  Read more

Desrosiers-Bonin, Diane (Advisor)  Read more

The study presented in this thesis arose as a side-issue of a main investigation on the preservation of whole blood assigned to the Department of Biochemistry, by the National Research Council, shortly after the outbreak of war in 1939. During the recent Spanish Civil War, the extensive use of stored blood in the treatment of wounded soldiers and civilians had demonstrated the practicability and the usefulness of stored blood in modern warfare. As a result, a widespread interest developed in many countries in the improvement of methods of preservation. The idea of the Blood Bank was introduced in the United …  Read more

This thesis investigated sentence comprehension impairments in patients with dementia of the Alzheimer's-type (DAT). The first three experiments investigated the nature of the impairments using different tasks. Across tasks, patients' performance by syntactic complexity, but was poorer for sentences that had more propositions. Results are discussed in terms of a post-interpretive processing impairment in these patients. Two additional experiments investigated possible determinants of sentence comprehension impairments in DAT. One employed a dual-task paradigm to examine the effect of increasing the processing load associated with sentence comprehension. The other examined processing resource limitations in the patients tested in the first and …  Read more

Latimer, Eric A (Supervisor1)  Read more

The evolution of the Unemployment Insurance Programme since 1940 has led to the abandonment of the intended insurance nature of the programme. As a result, it can no longer be considered solely an income protection scheme. Rather, it has evolved into an income maintenance plan aimed at supplementing the income of seasonal workers in high unemployment regions. As a consequence, there has been an interprovincial transfer of unemployment insurance funds from low to high unemployment regions. The regional characteristics of the programme have also distorted the structure of labour markets in high unemployment regions by attracting workers in seasonal industries …  Read more

How neurons wire together to form circuits is a central pillar of our mental abilities and often leads to disease when gone awry. This fact highlights the importance of neurons correctly finding their synaptic targets after growing their axon in a target area. This is called synaptic specificity and is among the most challenging feats developing neurons face: within a dense thicket of dendrites, a neuron must find a specific target among hundreds of potential candidates. How do these cells meet this challenge?One idea is that they express molecular cues on their cell surface that recognize targets bearing matching cues, …  Read more

This study examines the importance of age, education, and the health system reforms in the mid 1990's on the utilization of five health services: specialists' visits, family doctor visits, non-physician health professional visits, hospital use, and home care services. The analysis focuses on the Canadians 45 and over, and uses data from the National Population Health Survey. Results. Age per se has only a minor effect on utilization; the relative high utilization rates observed among the aged relate to the use of services by people with chronic conditions, whose prevalence is higher among the aged. Education has little impact on …  Read more

Neutrophil aggregation has been widely evaluated from changes in light transmission. Using direct particle counting, we demonstrated that light transmission does not accurately reflect aggregation, and showed that in contrast to previous reports, newborn neutrophils do not aggregate irreversibly. We developed a flow cytometric technique to measure the kinetics of neutrophil aggregation, including latent times for onset of aggregation, initial forward and reversal rates, and maximal extents of aggregation. The kinetics of neutrophil aggregation were related to changes in initial cell concentration, stir speed (shear), and activator type and concentration. Physiologic activators stimulated reversible aggregation, accompanied by an exponential decay …  Read more

The Simonette and Ante Creek reservoirs are part of a series of extensive Upper Devonian reef complexes or buildups in the West-central Alberta Basin. Buried at depths of about 3510 and 3380m, they are one of the few places in the Alberta basin where dolostone and limestone reef reservoirs can be compared, especially their similarities and differences in reservoir characteristics. Ante Creek's lithofacies are similar to other Swan Hills buildups, and can be subdivided into 7 buildup stages. The Leduc Formation in Simonette can be subdivided into 6 buildup stages, however, facies recognition is difficult as primary textures are obliterated …  Read more

As recently as 1995, sweet blood did not resonate broadly as an urgent transnational concern. This thesis chronicles how diabetes mellitus, sweet blood, became recognized as a social problem besetting Canada, among many other countries. This ethnographic study brings anthropological theories---developed for the most part to analyze the lives of "non-Western" peoples---to bear on "Western" philosophy, science, medicine, mass media, governments, and commerce. Throughout, this thesis challenges received wisdom about disease, technologies, kinship, commodification, embodiment, and personhood. This thesis argues that a statistical concept, the population, is the linchpin of both politics and economics in large-scale societies. Statistically-fashioned populations, combined …  Read more

As the number of civilian users of the United States Air Force's Navstar Global Positioning System (GPS) continues to increase at such a staggering rate, the government's exposure to potential liability also increases. The purpose of this thesis is to establish a legal framework to apply to GPS-related claims against the United States, primarily against the Air Force as operator of the system. Part I consists of three chapters. Following an introductory chapter, Chapter II describes the system and the general characteristics of GPS. Chapter III outlines the military uses of the system and the increasing and evolving civilian uses. …  Read more

As early as 1877 Pasteur noticed inhibition of the growth of the anthrax bacillus by certain air-borne contaminants and two years later DeBary emphasized the significance of the antagonistic interrelations among microorganisms. At about the same time another worker (87) noticed that certain bacteria disappeared much more rapidly in unsterilized soils then in sterilized soils, and it was even suggested that the substances produced by the dominant organism might be of use in the control of bacterial infections. [...]  Read more

The Planar Cell Polarity (PCP) signaling pathway is crucial for tissue morphogenesis. Vangl2 protein is central in the PCP pathway: its loss is embryonic lethal causing neural tube defects in mice and humans. In the kidney, PCP signaling is thought to be important for the organization of glomerular epithelial cells, podocytes, along the glomerular basement membrane. Podocyte cell protrusions, foot processes (FPs), are critical for kidney filtration functions; loss of FP architecture results in proteinuria and, in severe cases, focal segmental glomerulosclerosis (FSGS). Additionally, an effect of PCP pathway on podocyte shape, actin rearrangement and cell motility was previously described. …  Read more

This thesis investigates both the structure of supersingular isogeny graphs with full level N structure, and random walks on the volcano-like graphs arising from ordinary isogeny graphs (known as isogeny volcanoes). In particular, this thesis uses strong approximation to explore the number of connected components in supersingular isogeny graphs with full level N structure and analyses a probability measure defined on the vertices of an isogeny volcano. This measure describes the probability that a certain vertex is reached in a simple random walk on the graph. The random walk represents the action of the Hecke operator on the ordinary elliptic …  Read more

Plusieurs pharmaceutiques, tel que l’antibiotique sulfaméthoxazole ne sont pas totalement éliminées lors du traitement des eaux usées et ne sont pas biodégradables dans l’environnent. Au cours de ce projet, deux types de solutions de sulfaméthoxazole ont été étudiées : à base d’eau traitée par osmose inverse et à base d’eau usée municipale. Des solutions ayant des concentrations de 60 mg/L et 100 μg/L ont été traitées par ozonation.Une méthode d’extraction en phase solide a été développée afin de préconcentrer les échantillons avant l’analyse par HPLC. Les solutions de sulfaméthoxazole composées d’eau traitée par osmose inverse et d’eau usée ont requis …  Read more

Metcalfe, Chris (Supervisor2)  Read more

On a compare la capacité des macrophages et des neutrophiles a supporter la reactivité des lymphocytes purifies dans la reaction d'une culture mixte de leukocytes (MLC): seuls les macrophages étaient actifs. Une seconde étude expérimentale à été menée dans le but de prouver le role des antigènes de transplantation (H) dans l'amorçage de la reaction MLC, dans la formation des lymphocytes cytotoxiques (CL) pendant cette reaction, et comme cible des CL dans la reaction de lympholyse par voie cellulaire (CML). [...]  Read more

Quality of measurement is a fundamental issue in medical research and clinical practice, of relevance for any inference or decision-making process. Reliability, as an estimate of the variability in the domain of repeated measurements, is an important component of the quality of measurements. Reliability indices are frequently used and presented in the medical literature and a considerable amount of methodological research has been conducted on this topic in the last decades. However, the debate is still open on some theoretical and operational aspects. Available knowledge concerning reliability, particularly for categorical data, is not easily accessible since it is often confined …  Read more

Chen, Lawrence R. (Internal/Supervisor)  Read more

The term polymer brush refers to the class of structures formed by polymers when attached to a surface at sufficiently high surface density so as to cause the polymers to stretch away from the surface to avoid each other. Considering specifically brushes formed by flexible, linear homopolymers attached by a single end to an impenetrable planar surface, this thesis investigates the stability of the laterally homogeneous phase of the brush in response to fluctuations of polymer density. The controlling factors studied are: the energetic interactions of the polymers with the bath of solvent particles in which the brush is immersed; …  Read more

The prescription of R. M. Wald for determining a thermodynamic first law for stationary, axisymmetric, asymptotically flat black holes in general theories of gravity is applied to the effective Lagrangian for the bosonic sector of low-energy heterotic super-string theory. It is found that the presence of the gauge fields necessitates an alteration of the prescription. Specifically, the Lie derivatives with respect to the Killing vector of the gauge fields are non-vanishing. This introduces new terms which ensure gauge-invariance of the final result in a natural way.  Read more

The human gut microbiota plays an important role in the maintenance of human health. It forms a tremendous and complex bacterial bioreactor located in the human intestinal tract. An imbalance of the gut microbiota ecosystem, a state called gut dysbiosis, can disrupt the microbiota's functions. Endotoxins are immunogenic molecules produced by the gut microbiota that cause metabolic endotoxemia, a disorder characterized by low levels of circulating endotoxins that contribute to the development of many human diseases, including type 2 diabetes mellitus, obesity, and liver, cardiovascular, and inflammatory bowel diseases. Although many strategies have been developed to combate high dose endotoxemia …  Read more

In this study, predation efficiency of three guppy ( Poecilia reticulata) size classes was evaluated at various vegetation densities in a series of circular aquaria containing plastic plants closely resembling Ceratophyllum demersum. The effect of vegetation density was most apparent among large fish where predation efficiency greatly diminished from 12.35 mosquito larvae (Aedes aegypti) to 4.68 as vegetation densities rose from 3 to 19 plants/700 cm2. Over that same range of increasing vegetation densities, predation among small fish remained unchanged, whereas among fish of intermediate size predation declined significantly but less precipitously than for large individuals. When presented with a …  Read more

This study tests the ability of the Canadian Land Surface Scheme (CLASS) to simulate sensible and latent heat fluxes over two subarctic tundra sites in the Trail Valley Creek (TVC) drainage basin, North West Territories, Canada. CLASS simulations with and without the new organic soil parameterisation developed for peatland conditions were compared with three summer months of measurements at each site. The sites are located in a cryoturbated region and are underlain by continuous permafrost and feature mineral soil hummocks and organic soil inter-hummock zones. Results from the peatland version of CLASS showed significant improvement over the standard version although …  Read more

How "social change organizations" balance organizational imperatives with progressive, or "principled," values is a dilemma commonly addressed in the sociological literature (cf. Minkoff, 2002; Ostrander, 2004). This challenge is particularly important where organizations are undergoing a process of change (Kelley et al., 2005). However, few studies have used internal working conditions as a dynamic on which to measure this balance. Thus, using the internal dynamics of two contemporary human rights organizations, Amnesty International and Human Rights Watch, as a means of understanding these challenges, the broadest objective of this dissertation is to understand how organizations with principled values do or …  Read more

Dans ce mémoire, nous présentons les relations d’équivalence Boreliennes dénombrablesmoyennables via leurs nombreuse définitions équivalentes. Dans la troisième section,présentons une preuve directe provenant de Hayes que la définition de Connes, Feldmanet Weiss implique celle combinatoire par l’existence des fonctions Reiter. Nous adpatonsla preuve au cas des relations préservant la classe de mesure. Dans la quatrième section,nous donnons un relaxation de la définition de relations d’équivalence moyenables parune attribution mesurables de moyens et nous montrons qu’elle est encore suffisants pourdémontrer une version utile, malgré plus faible, de la théorème de sélection de bouts deJackson, Kechris et Louveau  Read more

Today, great emphasis has been placed on waste produced by the metals industry. Until recently, hydroxide precipitation was considered the ideal choice for handling metallurgical effluents. Metal hydroxides are stored in landfills, although they are not ultimately stable and may redissolve into groundwater with slight changes in pH. An alternative is to adsorb dissolved metals onto stabilized silica sols ("activated silica"), which are colloidal polymers produced by acidifying silicate solutions. Metal-loaded sol may subsequently be desorbed with concentrated acid. The products are a potentially valuable concentrated metal solution and recyclable sol. Dissolved metal adsorption with silica sols was compared with …  Read more

Synthesized sound is ubiquitous in contemporary music and aural environments around the world. Yet, relatively little has been written on its cultural origins and meanings. This dissertation constructs a long history of synthesized sound that examines the century before synthesizers were mass-produced in the 1970s, and attends to ancient and mythic themes that circulate in contemporary audio-technical discourse. Research draws upon archival materials including late-nineteenth and early-twentieth century acoustics texts, and inventors' publications, correspondence, and synthesizer product manuals from the 1940s through the 1970s. As a feminist history of synthesized sound, this project investigates how metaphors in audio-technical discourse are …  Read more

Cross-linguistically, the notion 'minimal word' has proved fruitful grounds for explanatory accounts of requirements imposed on morphological and phonological constituents. Word minimality requires that a lexical word includes the main-stressed foot of the language. As a result, subminimal words are augmented to a bimoraic foot through diverse strategies like vowel lengthening, syllable addition, etc. Even languages with numerous monomoraic lexical words may impose a minimality requirement on derived words that would otherwise be smaller than a well-formed foot. In addition, the minimal word has been argued to play a central role in characterizing a prosodic base within some morpho-prosodic constituent …  Read more

This work focused on the natural development of neurotachykinin-1 (NK-1) receptors in the porcine brainstem during postnatal development (using 4 ages vs adult), and on alterations in these receptors after single and six-daily repeated clustered hypoxia (using young and older piglets). NK-1 receptor localization and densities were determined by quantitative autoradiography, using mono-iodinated Bolton-Hunter substance P ([125I]-BHSP). Slide-mounted brainstem sections, incubated in [125I]-BHSP and then exposed to film, have shown [125I]-BHSP binding throughout many brainstem nuclei and tracts, including the ambigual/periambigual (nAmb), dorsal motor vagal (dmnv), hypoglossal (nHyp), lateral reticular (nRL), gigantocellular (nGC), solitary tract (nTS), medial parabrachial (nPBM), and …  Read more

The author spent three months during the summer of 1952 at a training camp with an infantry company of the Canadian Army. He spent most his time with the recruits in the company, watching them while they were training, drinking in the canteen, hanging around the hut, and resting between training periods. He went on a three-day leave with them, and carried his pack and tramped with the, on three different schemes.  Read more

Cette étude présente une analyse de la représentation de la douleur chronique et épisodique dans les récits de vie en mode narratif. J'ai compulsé six ouvrages contemporains de mémoires, chacun s'intéressant à l'expérience de douleur chronique de l'auteur. Dans le domaine de l'étude de la douleur – en sciences humaines et médicales –, la capacité de la langue à représenter la douleur est un enjeu controversé. Plusieurs affirment que la douleur est difficile à transmettre par le langage parce que, d'une part, nous échouons à en faire l'expérience en tant qu'événement significatif. La narration est le mode de communication le …  Read more

Son, Seok-Woo (Internal/Supervisor)  Read more

The present thesis tackles the problem of on-line steady state security assessment in electric power transmission networks. The contingencies examined include generation shift as well as line (transformer) outages. The methodology developed is Pattern Recognition-motivated although not entirely within the frame of traditional statistical Pattern Recognition. Due to the fact that training samples are rather expensive to obtain in electric power engineering, our first concern was to develop and implement algorithms carrying out the task of intelligently acquiring training points. It is found that these algorithms, permit to substantially reduce the amount of off-line computational effort while, at the same …  Read more

Eighteen-month-old adult female Peking Ducks (Anas platyrhynchos) were placed in the Ottawa, and St. Lawrence rivers for periods varying between 14 and 72 days during the summers of 1987, 1988 and 1989. Two stations located on Lake St. Francis were selected for establishing a time-curve for the accumulation of organochlorine pesticides (OC) and PCB in the liver. The ducks rapidly lost weight during their first 20 days in the natural environment but stabilised after about 40 days. This weight loss was caused by the stress of habitat, change, the energetic costs in searching for food and moulting. There was a …  Read more

La marchabilité, qui est une conceptualisation des facteurs de l’environnement bâti et social influençant la marche, peut être analyser à différentes échelles et niveaux d’objectivité. La marchabilité subjective, une mesure de la perception deconvivialité de l’environnement piéton, a été moins étudiée que les indices de marchabilité objectifs et ce, même s’il a été démontré que ces derniers sont limités dans leur capacité à refléter l’expérience piétonne dans des environnements variés. De plus, peu de recherche à analyser comment la relation entre l’environnement bâti et les habitudes de marche varie entre diverse groups sociaux. La marchabilité a été mesurée plus fréquemment …  Read more

A problem often encountered in epidemiology is the evaluation of the validity of a questionnaire administered to subjects. This is usually performed with the help of the intraclass correlation coefficient (ICC). The ICC, however, has several drawbacks. This thesis addresses questions on the use of Generalized Procrustes analysis (GPA) to estimate interrater reliability in epidemiology. GPA is one of the family of methods that are concerned with the analysis of data arising from several subjects. It is a powerful multivariate statistical technique developed in the framework of sensory evaluation to primarily assess interjudge reliability and furthermore to measure the effect …  Read more

Panagiotoglou, Dimitra (Supervisor1)  Read more

Although flow deflectors are routinely placed in streams to create fish pool habitat, there is dissent in the literature as to what constitutes for them an appropriate design height to ensure their success. Our objectives were to (1) examine the temporal evolution of bed topography around submerged deflectors in a laboratory flume, for different deflector heights and discharge; and (2) quantify the flow dynamics in their vicinity. Results indicate that, all else being equal, higher deflectors (characterized by less overtopping) produce a greater volume of fish pools. In contrast, over a fixed deflector design, a higher discharge (synonymous with greater …  Read more

The mining industry is one of the most energy intensive sectors of the economy, accounting for almost 2% of the world's electrical consumption. In a mill, most of this energy is spent in comminution processes, especially grinding. As the conventional grinding techniques are reported to present low efficiency, new methods have been proposed to pre-treat the ore, making it easier to grind. Among these techniques, Microwave Assisted Comminution (MAC) has presented great potential to reduce the energy required in grinding and also to improve liberation and flotation. MAC relies on the fact that minerals present different heating rates when microwave-treated. …  Read more

Childress, Jack (Supervisor1)  Read more

Paradis, Gilles (Supervisor)  Read more

The early region of polyomavirus encodes three proteins capable of causing tumors in vivo as well as cellular transformation in vitro. Polyomavirus middle T antigen has an associated tyrosine kinase activity due to its interaction with the cellular tyrosine kinase pp60$ sp{ rm c-src}$. To more closely characterize the interaction of these two molecules I have sought to express polyomavirus middle T antigen and pp60$ sp{ rm c-src}$ in insect cells. A variety of transfer vectors have been designed to allow the introduction of foreign genes into the genome of baculoviruses. cDNAs encoding polyomavirus middle T antigen and pp60$ sp{ …  Read more

The met protooncogene encodes a receptor tyrosine kinase that is deregulated through overexpression in certain human tumor cell lines and oncogenically activated following a genomic rearrangement which generates the hybrid protein p65tpr-met. Whereas the tpr-met oncogene product efficiently transforms Fischer Rat 3T3 fibroblasts, cDNA clones encoding two met receptor isoforms isolated from tumor cells do not induce cellular transformation. This suggests that tpr sequences may play a role in the oncogenic activation of the met kinase. The molecular mechanisms underlying oncogenic activation of met were elucidated and were shown to involve constitutive dimerization of the met kinase domain mediated by …  Read more