McGill University Thèses et mémoires par auteur commençant par R

Les personnes souffrant d’anxiété sont à risque plus élevé d’être rejetées, d’être isolées socialement, et d’avoir d’autres problèmes interpersonnels. Ces difficultés sont à leur tour des mécanismes qui mènent à l’aggravation de l’anxiété au cours du temps. De nombreuses études ont préalablement déterminé les niveaux moyens de comportement interpersonnel associés à l’anxiété qui aggravent le risque de difficultés interpersonnelles. Toutefois, il n’existe aucune enquête sur l’association entre l’anxiété et la variation intra-individuelle dans le comportement interpersonnel. La recherche présentée ici a examiné le lien entre l’anxiété et la variation intra-individuelle dans un comportement spécifique, le “flux”, et la variation intra-individuelle …  Read more

Causal reasoning is an important and complex process, in which individuals have multiple sources of information available to inform their judgments. An enduring tension exists between what cues to causality people use and focus on in acquiring causal knowledge and making causal judgments. Much research on causal reasoning has focused on how people use information about covariation in this process. More recently, research has shown that people seek and use information about causal mechanisms to inform their causal inferences. Consequently, an important theoretical question is how people combine knowledge about causal mechanisms, that is, how a candidate cause works to …  Read more

Jaksic, Vojkan (Supervisor1)  Read more

We present a study of the role of regularity of perturbations in the control of quantumfluctuations appearing in the first law of thermodynamics in quantum mechanics. These fluctuations areencoded in the so-called heat full statistics measure, motivated by considering differences in energymeasurements at times 0 and t. We introduce the suitable notions of regularity of the perturbationthat ensure polynomial or exponential decay of this measure at infinity. We also obtain control in t,and necessity of these conditions for decay in concrete models of quantum field theory.  Read more

En droit de la concurrence, les normes de preuve sont rattachées au fond du droit ou à la procédure. Cette dichotomie restreint l'analyse juridique : elle isole des aspects inséparables du standard juridique, point de référence essentiel pour les entreprises car il détermine les éléments nécessaires à une qualification d'entente. Ce mémoire compare le standard juridique applicable aux ententes aux Etats-Unis, au Canada et dans l'Union Européenne. On y démontre que le standard permet aux juges de contribuer à une politique de concurrence toujours plus influencée par la science économique. Sont alors en jeu l'efficacité de l'application du droit et …  Read more

During DNA replication, the replisome is responsible for rapid DNA unwinding and the exceptional fidelity of DNA synthesis. In E. coli, it's striking that despite its fast rate, effective DNA synthesis is achieved through the coordination of many transient processes rather than stable elements, as originally hypothesized. It's particularly surprising that all replicative DNA polymerases (Pol III), responsible for DNA synthesis, are exchanged every few seconds as a single unit, seemingly at odds with processive replication. Using single-molecule microscopy, we reveal that after dissociation, Pol III rapidly rebinds to the replication forks. This facilitated rate of association is driven by …  Read more

La thèse présente une nouvelle technique expérimentale pour mesurer les composants en-plane des tenseurs de diffusivité dans les matériaux poreux minces. La méthode est basée sur la diffusion d’oxygène provenant de l’air dans un échantillon poreux qui a été purgé avec de l’azote. La concentration d’oxygène transitoire est mesurée à une position fixe dans l’échantillon. La réponse est analysée utilisant la loi de Fick pour la diffusion transitoire en une dimension. La teneur d’échantillon est conçue pour permettre des changements en compression, qui peut changer la porosité et sinuosité du matériel. La méthode conçue fournit des mesures précises, rapides et …  Read more

Formation of Pb and Ca precipitates on a silica surface in the presence of sulphate and carbonate under neutral to alkaline condition is studied using zeta potential measurements, Scanning Electron Microscopy (SEM), and X-Ray Photoelectron Spectroscopy (XPS). The effect of carbonate on displacing sulphate is discussed. In the Pb/sulphate system, precipitates of predominantly Pb-oxide/hydroxide formed on the silica surface. In the Pb/carbonate system, the precipitates were predominantly Pb-carbonate/hydroxy carbonate. Precipitates in both the Pb/SO$ sb4$ and Pb/CO$ sb3$ systems were dispersed by addition of sufficient carbonate, the silica surface eventually becoming free of precipitates. This dispersion was considered to be …  Read more

Activation of sphalerite by lead ions in the presence of ethyl xanthate was investigated by microflotation, zeta potential measurements, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and extraction by ethylenediaminetetraacetate (EDTA). The source of lead, either from solution or contact with galena particles, proved immaterial. From EDTA extraction data flotation response was determined as a function of surface concentration of Pb ([Pb]surf, mg/cm2). A critical [Pb]surf ≃ 0.5 x 10-4 mg/cm2 causing activation was estimated. By combining with a Pb ion production model from the literature, the possibility of Pb activation for an ore of given Pb grade was …  Read more

Zien, Katherine (Supervisor1)  Read more

Roussos G Dimitrakopoulos (Internal/Cosupervisor2)  Read more

The vast research on modern architectural masterpieces and Louis I. Kahn's work in particular reveals various ways in which architects often use large, central spaces as ordering elements. Conventional methods of research tend to take the meaning of a "central space" as self-evident. Though one cannot argue against the validity of these methods, many things remain hidden by assuming something as obvious. This paper is anattempt to reveal what is overlooked about the "central space" by following differentlines of questioning. It studies Kahn's Phillips Exeter Academy Library in light ofphilosophical theories by Hans-Georg Gadamer, Maurice Merleau-Ponty and HannahArendt. These theories …  Read more

A PCR approach using degenerate primers specific for the highly conserved pore and S6 transmembrane domains of K+ channels was used to assess the diversity of K+ channels in the electric fish Apteronotus leptorhynchus. DNA sequence analysis has identified nineteen K+ channel genes, each of which can be classified into one of the four major families in a similar distribution to that in mammals. Also, an Apteronotus brain cDNA library was constructed and screened with mammalian K+ channel probes. The first K+ channel clone obtained displays remarkable amino acid sequence homology to rat Kv1.3 and Northern blot analysis and RNase …  Read more

Gamma-frequency burst discharge in pyramidal cells of the apteronotid electrosensory lateral line lobe (ELL) is necessary for signal processing. Bursting is dependent on an interaction between somatic and apical dendritic currents, in which spike broadening in the apical dendrite potentiates a somatic afterpotential that follows each rapid somatic spike. Somatic spike repolarization must be consistent in order for the afterpotential to be expressed soon after. The work presented in this thesis describes how the expression and differential subcellular distribution of two Kv3-type K+ channels in ELL pyramidal cells may contribute to this mechanism of burst discharge. I cloned a family …  Read more

Objective: The purpose of this multicenter observational study was to determine patient satisfaction and oral health-related quality of life (OHRQoL) with either conventional complete dentures (CDs) or mandibular 2-implant overdentures (IODs) in a 'real world' setting. Methods: Two hundred and three edentulous patients were recruited from eight centers. At baseline and at six months, they rated denture satisfaction on 100mm visual analogue scale questionnaires and OHRQoL using the Oral Health Impact Profile (OHIP-20). Results: Although both groups reported improvements, the IOD group reported significantly higher ratings of overall satisfaction, comfort, stability, ability to speak and to chew. Although OHIP-20 effect …  Read more

Piper, David (Supervisor)  Read more

This dissertation focuses on slaves and peasants as self-consciousness actors in northwestern Sierra Leone between 1896 to 1956. During this period, which covers almost the entire duration of British colonial rule in the region, these subaltern groups used covert and violent actions to protest the various demands---labour, tribute and taxation---of the state and the local elite. Covert actions like evasions, escapes and migrations became interwoven into the fabric of colonial rule. Violent actions, which tended to be spasmodic, erupted when social and economic conditions deteriorated sharply. Four major rebellions occurred during colonial rule in region. The first, spearheaded by local …  Read more

La schistosomiase est une des maladies parasitaires les plus importantes sur le plan socioéconomique, affectant plus de 200 millions de personnes à travers le monde. Le praziquantel est le seul médicament disponible pour le traitement de la schistosomiase dans la plupart des régions du monde et il est urgent de trouver un traitement de rechange viable pour complémenter ce médicament. Il a été démontré que les canaux ioniques de type pentamériques sensibles à de l'acétylcholine appartenant à la famille des récepteurs nicotiniques (nicotinic acetylcholine receptor, nAChR) sont la cibles de plusieurs médicaments vermifuges utilisés pour le traitement de diverses infections …  Read more

Szkopek, Thomas (Supervisor2)  Read more

La plasticité développementale – phénomène qui permet aux organismes d’altérer leur trajectoire développementale en réponse à différentes conditions environnementales – peut grandement améliorer la valeur reproductive des organismes et leur permettre ainsi d’endurer des périodes de stress prolongées, telles que celles crées par l’absence de nutriments. Le nématode C. elegans démontre de nombreuses formes de plasticité développementale; en réponse à un manque d’aliments ou à une surpopulation, il peut par exemple exécuter le stade de développement alternatif « dauer », et peut demeurer dans cet état jusqu’à plusieurs mois, ou jusqu’à ce que les conditions de son environnement ne s’améliorent. …  Read more

Nicolau, Belinda Farias (Internal/Cosupervisor2)  Read more

Water balance calculations were conducted for data obtained from a soil moisture characteristic to demonstrate the effect of different subsurface drain depths on the extent of droughtiness of a sandy soil. Laboratory experiments were conducted on samples of sandy soils of the St. Lawrence lowlands to determine pertinent physical and soil-water properties. These properties were used, together with published crop data, to determine the effect of different subsurface drain depths on the quantity of available water in the soils studied. Empirical relationships were derived among some of the properties measured, with the objective of enabling future drainage planners to make …  Read more

This case study examines the underground linguistic, cultural, and educational activism of Turk educators in Iranian Azerbaijan during the 1990s and 2000s in Tabriz and their continued activism in exile. Faced with the denial of linguistic and cultural education in their minoritized language and socio-political suppression, they turned to underground spaces and created their pedagogies and resources for mother-tongue-based education. Once persecuted by the government due to their activism and confronted with severe challenges, they were forced to leave the country into exile. From that time forward, they have continued their efforts, and since 2020, they have been operating virtually …  Read more

The Myc-interacting zinc finger protein-1 (Miz-1) is a ubiquitously expressed but poorly studied transcriptional transactivator that can bind to the proto-oncoprotein c-Myc, which is the main driver of a large number of different cancer types. In my thesis, I use murine T cell development as well as mouse models of T cell leukemia to broaden our biochemical understanding of the functions of Miz-1. At the beginning of my Ph.D., our lab had reported that Miz-1 plays an essential role during early stages of T cell development in the thymus, specifically at the β-selection checkpoint, which has important implications for T …  Read more

Daniel, Sam Joseph (Internal/Supervisor)  Read more

The Quebec Ministry of Education has implemented curriculum reforms that emphasize the integration of information technology into classroom teaching practices. Despite these efforts, however, many teachers appear to resist using computers in their classrooms. Some of these resistors are technologically literate! The purpose of this qualitative study is to better understand the reluctance of the technologically-literate teachers (with two to three years of experience) to integrate technology into their teaching practices. The six teachers participating in this study completed questionnaires and were individually interviewed using an open-ended approach. The data were then analyzed using the Constant Comparative Method. The results …  Read more

Soil-transmitted helminths (STHs) are a major burden on human health in developing countries. Ascaris lumbricoides, Trichuris trichiura and the hookworms, Necator americanus and Ancylostoma duodenale are the most prevalent STHs, infecting more than 1.5 billion people worldwide. School-age children are the most at risk of heavy infection with STHs and of developing severe morbidity, leading to malnourishment, with cognitive and educational deficits. Infection with STHs can complicate pregnancy, placing both mothers and children at higher risk of severe mortality.Large-scale treatment with benzimidazole (BZ) drugs, albendazole (ABZ) or mebendazole (MBZ), is the major control strategy to control STH infections in mass …  Read more

Adams, Charles J. (Supervisor)  Read more

The ‘taiga’ rim of Mongolia’s Darhad Depression is home to 300-350 Duha nomadic reindeer herding hunter-gatherers. Indigenous to this taiga, Duhas are the only humans who permanently reside in Tengis-Shishged National Park (TSNP). Unlike most life there, Duhas and their livestock are not under TSNP’s ‘protection,’ but are prime targets of TSNP’s restrictions on mobility, hunting, gathering and pasturing. Conservation conflict arises as Duha traditional livelihoods are criminalised in TSNP, one of three state-governed reserves that compose Ulaan Taiga Specially Protected Areas (UTSPAs). UTSPAs and Lake Hövsgöl National Park (LHNP) comprise Mongolia’s portion of the Darhad Depression’s taiga rim. The …  Read more

The current research on neutrinos is motivated by the long-standing question of matter-antimatter asymmetry and the search for dark matter. We look at the different neutrino-related phenomena and interactions to better understand their properties and nature, i.e., are they Dirac or Majorana particles. One such important phenomenon is that of neutrinoless double-beta decay (0νββ). It is a hypothetical decay mechanism that, if observed, would prove that neutrinos are Majorana particles, which will have pronounced and far-reaching consequences for our understanding of the universe. nEXO is a tonne-scale experiment that aims at searching for 0νββ decay in 5-tonnes of liquid xenon …  Read more

The history of apparent movement begins in the 1820's (Boring, 1942), but its full importance for psychology was not recognized until the publication of Wertheimer's paper, Experimentelle Studien über das Sehen von Bewegung, in 1912 (translated in greater part in Shipley, 1961). Wertheimer saw the significance of the tact that, under certain temporal conditions, the successive presentation of a pair of stationary visual abjects "at a considerable spatial distance from one another," evokes the perception of movement. He called this impression of motion in the spatial interval between the two abjects the phi-phenomenon. [...]  Read more

The affects of cue position and rewarded pretraining on successive black-white discrimination learning were studied using 48 naive hooded rats. Two degrees of cue-reward separation and 60 vs.0 pretraining trials with the positive cue were employed in a go-no go paradigm in a runway. Thirsty Ss were to learn to run down the runway on trials with the positive cue and to withhold this response on trials with the negative cue. [...]  Read more

Dû aux changements climatiques, la demande pour des carburants capables d’accélérer la transition vers les énergies durables ne cesser d’augmenter. Le gaz de produit obtenu par gazéification de la biomasse est un candidat potentiel pour remplacer le gaz naturel dans les turbines à gaz, parce qu’il est composé d’un mélange gazeux d’hydrogène, de vapeur, de monoxyde de carbone et de méthane. Cependant, le processus de gazéification libère de l’ammoniac et d’autres composés azoté, qui sont responsables d’une augmentation substantielle des oxydes d’azote, NOx, un polluant cancérigène, dans les gaz d’échappement. Donc, il y a eu récemment un effort pour comprendre …  Read more

Abstract IntroductionL’encéphalopathie ischémique hypoxique est la cause la plus fréquente d’encéphalopathie néonatale, et entraîne une morbidité ainsi qu’une mortalité significative. D’un point de vue éthique et clinique, le pronostic neurologique est fondamental dans les soins apportés aux nouveau-nés atteints d’une encéphalopathie ischémique hypoxique. Toutefois, la prédiction précise des conséquences neurodéveloppementales de l’encéphalopathie ischémique hypoxique est particulièrement difficile, et remplie de défis. Présentement, la recherche dans ce domaine ciblé est limitée. ObjectifsCette thèse vise à présenter une revue de la littérature actuelle sur le pronostic et la pratique du pronostic de l’encéphalopathie ischémique hypoxique néonatale, en se concentrant sur les défis …  Read more

Through myelination, specialized glial cells, including oligodendrocytes in the central nervous system, wrap membrane processes around neuronal axon segments forming multilamellar myelin sheaths. As it is critical to normal motor and cognitive function, furthering the understanding of myelin formation and function as well as degeneration and dysfunction is of high importance. By and large, in vitro myelination studies involve unstructured co-cultures of neuronal and glial cells. However, these systems are often beset by difficulties in consistent replication, control on a single cell level, and microenvironment manipulation. With innovations in techniques to control cell growth, investigations of structured co-cultures are becoming …  Read more

Soleimani, Vahab (Supervisor2)  Read more

Dans cette thèse, la phase orthorhombique à basse température (Pmn21) relativement moins explorée de l'orthosilicate de lithium et de fer (Li2FeSiO4, LFS) est étudiée comme un candidat potentiel pour une cathode à haute densité énergétique. En particulier, le LFS est synthétisé, accordé mécanochimiquement, modifié par voie interfaciale et caractérisé par voie électrochimique dans le but de concevoir des cathodes stables et performantes à haute densité. Dans ce contexte, la première partie de cette recherche fut consacrée au traitement mécanochimique de particules de Pmn21 LFS orthorhombiques monophasées synthétisées par voie hydrothermale. De plus, le comportement structural du LFS traitée mécanochimiquement fut …  Read more

Gehring, Kalle Burgess (Supervisor1)  Read more

Trempe, Jean Francois (Internal/Supervisor)  Read more

This thesis uses theory and simulation to elucidate the fundamental principles and key mechanisms that govern demixing in compressible polyolefin solutions and its detection using acoustic wave propagation. Demixing by pressure-induced phase separation and its acoustic detection has direct applications to the industrial manufacturing of polyethylene based on the solution polymerization process, and is an evolving area of fundamental polymer thermodynamics.The two models developed, implemented and analyzed in this thesis for the structure and kinetics of pressure-induced phase separation in compressible polymer solutions and its acoustic detection, integrate total mass, component mass, momentum with the Sanchez-Lacombe equation of state, Newtonian …  Read more

La manipulation précise, rapide et contrôlée d'échantillons biologiques tels que des cellules ou des bioliquides est essentielle pour de nombreux processus et analyses en génie biomédical. Ces dernières années, la technologie "Lab-on-a-Chip" (LoC) a attiré beaucoup d'attention pour la manipulation d'échantillons biologiques, leur caractère miniature leur conférant une haute précision, un excellent contrôle spatial, une consommation minime de réactifs et d'échantillons, un haut potentiel de parallélisation, en plus d'avantages spécifiques à chaque application. Cependant, les lois d'échelle et la dominance des forces de surface et de friction aux micro-échelles nécessitent l'intégration d'actionneurs physiques aux systèmes LoC pour exploiter pleinement leur …  Read more

Eutrophication and cyanobacteria blooms are a growing problem in Missisquoi Bay of Lake Champlain in southern Quebec, and these are largely attributed to non-point source phosphorus and nitrogen (N) pollution from agricultural land in the surrounding watersheds. Residual soil N left after crop harvest contains soluble and particulate forms of N that are at risk of being transported from tile drained agricultural fields to waterways. This study aimed to find the sources of soluble N (mainly nitrate; NO3-N) and particulate organic N (PON) that are susceptible to loss, and the transport pathways by which they move to surface water through …  Read more

In one of his many letters to Rose Leicester in The Lake, Father Oliver Gogarty warns her against falling into “a divorce between the world of sense and of the spirit.” Rose was first ostracized and later exiled from her native Ireland for having borne a child out of wedlock, and Gogarty fears that he and the persons in his parish have driven her into a non-Catholic environment where she is losing her faith and, as he puts it, over-indulging in the senses, to the detriment of her spiritual life.  Read more

The stress response is conserved among eukaryotes and affects different cellular functions including protein transport. Here, we have investigated the effect of different types of stress on classical nuclear protein import as well as nuclear import of Ssa4p family of heat shock proteins in Saccharomyces cerevisiae. Under normal conditions, Aequorea victoria green fluorescent protein (GFP), carrying a classical nuclear localization sequence (cNLS-GFP) is nuclear. However, cNLS-GFP equilibrates throughout the cell upon exposure to heat, ethanol, H2O2 or starvation. Redistribution of the small GTPase Gsp1p, a soluble nuclear transport factor, correlates with cNLS-GFP equilibration. This suggests that a collapse of the …  Read more

Spencer, John H. (Supervisor)  Read more

Similar to passive exposure to cigarette smoke, building occupants, in homes and in offices, are passively exposed to volatile organic compounds that are being emitted form surfaces of interior finishes and furnishings. Identifying emissions from surfaces of interior finishes and furnishings requires in-situ sampling. Interior finishes and furnishings used in homes and offices are many and varied. Current available methods used for sampling surface emissions from interior finishes and furnishings require the use of environmental chambers in laboratory settings. The in-situ applications of these lab-based chambers are limited. A novel method for in-situ surface emission sampling is needed. This thesis …  Read more

La négligence et l'abus au début de la vie sont associés à un risque accru pour le développement des troubles de l'anxiété et de la dépression majeure chez l'humain. Les variations de léchage maternelle / toilettage (LG) d'origine naturelle chez la mère rat, sont associés avec le niveau de peur et aussi le nombre de neurones qui survivent dans l'hippocampe chez les rejetons adultes. La peur accrue chez les rongeurs est associée à une réduction du nombre des nouveaux neurones dans l'hippocampe chez l'adulte. Le traitement chronique avec l'inhibiteur de la recapture de sérotonine sélective, la fluoxétine est associée à …  Read more

Abstract:The ability to localize noxious stimuli, also known as nociceptive topognosis, is critical for animal survival. Anterolateral system neurons (AS), many of which are commissural, transmit nociceptive information from the periphery to different brain regions. Indeed, mice with spinal cord-specific loss of the netrin-1 receptor Dcc are unable to accurately localize noxious stimuli, similar to DCC mutant humans, but the identity of the ASs whose miswiring causes the topognostic deficits is unknown. A recently characterized transgenic mouse, Phox2aCre, labels a distinct population of spinal AS neurons in spinal laminae I and V, with many of them expressing Dcc. To see …  Read more