McGill University Thèses et mémoires par auteur commençant par C

La victimisation par les pairs est une expérience répandue et potentiellement néfaste pour les jeunes en début d'adolescence, et les jeunes souffrant de symptôme d'anxiété et de dépression risques particulièrement de faire l'objet de provocation venant de leurs pairs; comme tel, la victimisation accrue vécue par les jeunes avec des symptômes d'anxiété et de dépression pourrait être expliquée, du moins en partie, par une réponse inadaptée à la provocation par les pairs. Dans cette thèse, j'ai testé l'association entre les symptômes d'anxiété et de dépression et la réponse à la provocation physique, verbale et relationnelle rapportée par les jeunes, incluant …  Lire la suite

La petite corbeille d’Asie Corbicula fluminea est un des mollusques les plus envahissant du monde. Dans les régions tempérées du nord, cette espèce subtropicale est typiquement limitée aux eaux artificiellement chauffées. Sa distribution a toujours été pensée d’être limitée par sa intolérance aux températures moins de 2ºC, basée sur une étude souvent cité qui a étudié une seule population du sud. Cependant, des populations hivernantes ont été découvertes dans des lacs et des rivières dans le nord-est de l’Amérique du Nord au cours des dernières années. J’ai exploré l’hypothèse que la tolérance au froid de C. fluminea varie à travers …  Lire la suite

Neurons are organized in functional circuits to allow an organism to perform complex behaviors. The mechanisms that dictate self-assembly of hard-wired neuronal circuits during development are still poorly understood. How are neurons able to distinguish correct from incorrect synaptic targets when they are faced with thousands of possible partners? To address this question, my dissertation explores the molecular mechanisms that regulate synaptic specificity in a hard-wired neuronal circuit of the model organism Drosophila melanogaster. I describe a method that allows combined structural and functional analysis of axonal targeting in single identifiable sensory neurons. This method is used to demonstrate that …  Lire la suite

Des expériences de perte de fonction ont démontré que la mise en place de l'architecture du squelette des membres requière la fonction des gènes HoxA et HoxD. Cependant, le rôle de ces gènes au cours de l'osteochondrogenèse est inconnu. Le but de mon projet de recherche était de définir ce rôle.En absence des gènes HoxA/D, le développement des membres est compromis dès les stades précoces, bien avant le début de l'osteochondrogenèse. Par conséquent, j'ai généré et analysé des inactivations conditionnelles des gènes HoxA/D dans le lignage osteochondrogenic afin d'établir le rôle de ces gènes au cours du développement osseux. Mes …  Lire la suite

This thesis investigates the role that topological defects (cosmic strings and textures) can play in producing a variety of cosmological and astrophysical phenomena. The main text is built out of a series of five published works, and one work which was submitted to a preprint archive. Following a general introduction, the thesis is split roughly into three parts. First, the impact of low frequency radiation from cosmic string loops on the global 21-cm signal at cosmic dawn, as well as on the observed distribution of fast radio bursts, is considered. Next, cosmic textures are constrained by considering their energy injection …  Lire la suite

Il existe une hypothèse qui stipule que la matière noire est considérée comme étant un état lié de boson de jauge suivant une théorie de SU(N), surnommée boule de glu 'dark'. Ces boules de glu n'ont pas de relation directe avec le modèle standard, mais sont en effect, en mesure de se décomposer en segments égaux de particules médiatrices, phi, ayant une grande masse. Nous considérons plusieurs scénarios dans lesquels les particules phi sont liées avec hypercharge U(1), de puissantes forces SU(3), et des bosons de Higgs respectivement. De plus, nous considérons l'approche numérique afin de résoudre l'équation de Boltzmann …  Lire la suite

The aim of this thesis is to try to bring some clarity and perspective into the controversy generated by Ivan Illich's theory of the necessity for a deschooled society. Furthermore it attempts to elaborate on how Illich's concepts originated and evolved. In this respect, it strives to present all of the elements which have had an impact upon Illich's intellectual formation and his subsequent religious, social, and educational philosophy. The method of inquiry for my thesis is to investigate the various experiences, including definite influences, which contributed to shaping Illich's attitudes towards society, technology, and formal education. Since all of …  Lire la suite

Reduced access to atmospheric oxygen greatly increased early instar Aedes aegypti mortality. Data suggest that death was by drowning mainly because slow swimming speed and low visual acuity delayed larvae from finding access to air. Late instar larvae experienced developmental delays when food depletion in the immediate vicinity of the breathing site forced them to forage farther away. As the distance between feeding and breathing sites increased, feeding efficiency of fourth instars may have declined enough to reduce their pupation success and to cause increased pupal mortality, reduced adult emergence and sex ratio skewed in favour of males among emerging …  Lire la suite

The legendary adventures of the giants Pantagruel and Gargantua have been the subject of several researches of the sixteenth century scholars of yesterday and today. The work of François Rabelais, famous author of the Renaissance, is particularly well known for the appearance of laughter, carnivalesque aspect and polyphony. In the wake of recent studies on the ventriloquism of women , this mémoire offers a specific look at the multiple speeches of female characters in the first four stories of François Rabelais. This study sheds light on the manifestations of the feminine gender by answering several questions: how does speech fit …  Lire la suite

Nearly half of nurses in Canadian hospitals work rotating shifts. Although necessary, shift work is associated with various short- and long-term health consequences such as cancer, cardiovascular disease, and gastrointestinal problems. These negative effects are partly caused by circadian misalignment (i.e., when one’s body clock is not aligned with the demands of the environment). While previous research has found that controlling light exposure can improve circadian alignment in individuals working permanent night shifts, light-based interventions are rarely adapted for and tested in rapidly rotating shift workers. In this field study, we developed and tested a light-based intervention to reduce fatigue, …  Lire la suite

Shirin Abbasi Nejad Enger (Supervisor1)  Lire la suite

Peroxisomes are organelles found in eukaryotic cells where several oxidative processes take place. Enzymes destined for the peroxisome generally contain either a C-terminal or a N-terminal peroxisomal targeting signal, named PTS1 and PTS2 respectively. These signals are cytosolically recognized by their correspondent receptors PEX5 and PEX7 prior to being recruited at the surface of the peroxisomal membrane where the complex docks onto PEX14. Then, enzymes are transported in a natively folded fashion inside the organelle where they are released. In trypanosomatids, other metabolic pathways, including glycolysis, are also segregated in the organelle, which has been renamed the glycosome to better …  Lire la suite

The fuel ethanol industry is now making use of a very efficient process where virtually all sugar substrates are converted to ethanol. Nevertheless, some metabolic by-products excreted from Saccharomyces cerevisiae tend to reduce the ethanol yield. Of such, glycerol is the major one, accounting for about 5-10% relative to the amount of ethanol produced. Glycerol plays an important role in maintaining the redox balance within the cells by oxidizing the cytosolic NADH under anaerobic conditions. It is also believed that it acts as an osmoprotectant and would be favourably produced in high osmotic pressure conditions. In order to mitigate the …  Lire la suite

The objective of this work was to develop a computer application that could be used to optimize the ply angles of laminates used in a specific structure. Optimization is performed for finding laminates which yields the highest fundamental frequency and/or highest energy dissipation associated to the first mode. An extensive literature review is presented to discuss the needs for such a tool and the techniques that can be used in its construction. The various objectives and requirements of the computer program are discussed. The application was tested for various finite element models and the results were successfully compared to reference …  Lire la suite

No safe and effective vaccine exists against respiratory syncytial virus (RSV), the main viral cause of lower respiratory tract infections in young children. Proteosome-based adjuvants, derived from the outer membrane proteins (OMP) of Neisseria species are potent inducers of mucosal and systemic immunity in humans and animals. RSV subunit vaccines based on enriched RSV proteins (eRSV) were formulated with proteosomes (Pro) or its S. flexneri LPS-supplemented derivative, Protollin (Prl). Administered intranasally (IN) in BALB/c mice, the vaccines elicited systemic and mucosal RSV-specific antibodies and fully protected against RSV challenge without enhanced pulmonary pathology or evidence of a Th2-biased response (eg: …  Lire la suite

The separation of the boundary layer at the trailing edge of sails is considered in the present work. This problem was identified as one of the major reasons for the disagreement between existing theories and experimental results. The separation of the flow on flexible surfaces is a complex phenomenon because of the interdependence between the shape of the sail, the pressure distribution and the separation position. The problem is simplified by considering the flow over a two-dimensional sail set at design incidence to isolate the effect of the separation of the flow. A theoretical model predicting the pressure distribution around …  Lire la suite

The aim of the present research is to develop a theoretical model that could predict the trailing-edge separation over a circular-arc aerofoil and its effect on the pressure distribution, and on the lift. The model uses sources, in a potential flow, to simulate the effect of the separated region on the pressure distribution. An integral method, turbulent boundary-layer development, combined with the irrotational pressure distribution on the circular-arc predicts the point of separation. To make sure that trailing-edge separation is present alone and mostly to avoid any difficulties in predicting the boundary-layer flow after reattachment, the aerofoil is studied at …  Lire la suite

Le récepteur ErbB2 est surexprimé dans 25 à 30% des cancers du sein chez l’humain où il est associé avec un mauvais pronostic. Des modèles de souris transgéniques ont démontrés que ce récepteur agit en coopération avec la voie de signalisation du récepteur TGFβ afin de favoriser la migration et l’invasion de cellules de cancer du sein. En réduisant de manière transitoire le niveau d’expression de la protéine ShcA, il a été établi que cette protéine joue un rôle proéminant dans cette coopération entre les voies de signalisation ErbB2 et TGFβ. De plus, la diminution du niveau d’expression de ShcA …  Lire la suite

We study how the resonant decay of moduli fields from the scalar potential of the MSSM could affect large scale curvature perturbations. After introducing the theory of cosmological perturbations and of broad and stochastic resonance, we present the supergravity inputs necessary to study the MSSM moduli in a cosmological context. We find that the resonant amplification of large scale field fluctuations is allowed for a very small range of parameters and is harmless for large scale curvature modes.  Lire la suite

In this thesis a general method for the formulation of the dynamical equations of general $N$-axis, serial-type robotic manipulators of otherwise arbitrary architecture, with rigid and flexible links, is presented. The dynamic simulation of this type of manipulator is also included. The two different methods of formulation discussed here are the hybrid Newton-Euler (NE)/Euler-Lagrange (EL) formulation for the study of flexible-link manipulators and the NE formulation, for the study of rigid-link manipulators. The hybrid NE/EL formulation lends itself to a systematic and conceptually straightforward formulation for flexible-link manipulators, as opposed to the NE formulation which, in this case, will be …  Lire la suite

Research in decision making has identified the importance of prior knowledge and heuristics on decision making behaviour. These develop with experience in a fashion similar to how domain experts develop specialized knowledge structures and heuristic reasoning patterns. This research is extended to the domain of health and lay decision making in a series of studies characterizing conceptualizations of health and illness, information-seeking strategies, and the impact of medical information on lay decision making. Lay subjects included those with diabetes, heart disease, and no identified ongoing medical diagnosis. Semi-structured interviews and think aloud methodology were employed. Interviews focused on understanding of …  Lire la suite

The Slc11a family of integral, proton-coupled divalent metal transporters exhibits a high degree of conservation among phylogenetically distinct organisms and contributes to a variety of pleotropic effects in humans. The topology of mammalian Slc11a family members remains unclear and was investigated by insertion of hemagglutinin (HA) epitopes in the predicted hydrophilic segments of Slc11a2 isoform I, followed by cation transport assays to ensure proper protein function and targeting at the plasma membrane. Immunofluorescence, corroborated by a surface labeling assay, on stably transfected intact and permeabilized LLC-PK1 cells indicated that both termini and the intervening segments separating predicted transmembrane domains 4/5, …  Lire la suite

Introduction (Chapitre 1) présente un survol de la littérature concernant le mélanome et sa prévention. Le mélanome est le cancer de la peau le plus létal et celui dont l'incidence a la croissance la plus rapide (Trask et al., 2001). Son incidence en Amérique du Nord continue d'augmenter annuellement et pose un risque à un nombre croissant d'individus (American Cancer Society, 2018a; Canadian Cancer Society's Advisory Committee on Cancer Statistics, 2017). Du a cette croissance il est impératif d'implémenter des stratégies de prévention efficaces. Les directives cliniques recommandent L'Auto-examen de la peau (AEP) comme un élément essentiel du calendrier de …  Lire la suite

While providing non-invasive tissue detection, magnetic resonance imaging (MRI) presently possesses limited sensitivity for protein target recognition. This limitation was addressed for the target beta-galactosidase (beta-gal) by constructing three beta-gal-specific MRI probes. The probes are based on a bipartite design in which a vasoactive moiety known as a diazeniumdiolate (NONOate) is bound to a specifier, specifically galactose. Upon galactose' interaction with beta-gal, the NONOate is cleaved from galactose, and actively generates nitric oxide (NO). The released NO leads to microvascular permeability changes in surrounding tissues affecting localized T1 measurements. These changes serve as a quantitative index of beta-gal detection. The …  Lire la suite

The term nowcast is used to emphasize that a forecast is being produced for very short lead times, typically 0 to 6 h. Most nowcasting systems use weather radar as the primary tool for forecasting. Modern techniques use computer algorithms to compute these short-term forecasts, and have been shown to have more skill than human forecasters or numerical models alone. Applications of nowcasting span across many industries, with aviation being of particular importance. The essence of nowcasting can be summarized in two steps: (1) obtain a motion estimate for an existing storm, and (2) advect the current storm using the …  Lire la suite

A small addition of elements with a high affinity to oxygen can have a profound effect on the high temperature oxidation behaviour of many metals and alloys. In order to explain the improvement in oxidation resistance, the research was conducted using Ni-NiO as a model system of cation-diffusing oxides, and Ce as a typical reactive element. Three essential techniques were employed to modify the surface of Ni with Ce and CeO2: ion implantation, sol-gel technology, and reactive sputtering. The improvement of Ni oxidation resistance was assessed by oxygen uptake measurements mainly during the early stages but also for long-term exposures …  Lire la suite

Zygoma fractures are common and may potentially lead to negative aesthetic and functional consequences: cheek asymmetry, ocular globe asymmetry, infra-orbital nerve dysfunction. There has been a significant evolution in the treatment of zygoma fractures, with general transition from older, closed techniques to newer methods that involve greater exposure, more visualized reduction and increased stability of fixation. Little objective data is present to demonstrate the superiority of either technique. It is our hypothesis that each technique has significant disadvantages and the ultimate objective of this thesis was to develop and quantitatively demonstrate the superiority of a novel method of repair.First, we …  Lire la suite

Le renouvellement homéostatique de l’épithélium intestinal est assuré par une population stable de cellules souches adultes, les cellules souches intestinales (CSI), qui se renouvellent continuellement et donnent naissance à toutes les lignées épithéliales intestinales. Leur activité est contrôlée par les voies de signalisation Wnt, Notch, EGF et BMP. La signalisation du facteur de croissance TGFß est également impliquée dans la régulation de la prolifération, de la différenciation, de l’arrêt du cycle cellulaire et de l’apoptose des cellules épithéliales des villosités. Au-delà de son rôle durant l’homéostasie, la dérégulation de la voie TGFß est impliquée dans les lésions subies lors de …  Lire la suite

Bien que relativement brève, la période de l'entre-deux-guerres (1918-1939) a constitué un moment crucial pour le développement urbain et architectural de Varsovie et mérite d'être étudiée de manière plus approfondie en tant que chapitre distinctif de l'histoire de la ville. À la fin de la Première Guerre mondiale, l'émergence de Varsovie en tant que capitale d'un nouvel État-nation moderne, la Seconde République polonaise naissante, a incité les Polonais nouvellement autonomes à réévaluer profondément la ville par rapport à son nouveau rôle de noyau politique et administratif investi d'une signification symbolique suprême pour le nouvel État. Bien que la nouvelle capitale …  Lire la suite

In December of 2024, Alberta's United Conservative Party government passed a series of legislative changes affecting gender identity and expression, including Bill 27, a portion of which mandates parental consent for pronouns and preferred names for individuals aged 15 and under, and parental notification for those aged sixteen and seventeen. In publicly funded Catholic schools, where religious doctrine already imposes limitations on the inclusion and visibility of diverse gender and sexual identities, such policies pose an additional layer of repression. Existing literature highlights how Catholic schools, through religious doctrine, institutional surveillance, and parental rights rhetoric institutionalize heteronormativity to the detriment …  Lire la suite