McGill University Thèses et mémoires par auteur commençant par A

The pendant drop apparatus is the most reliable and accurate method of measuring the interfacial tension of polymer melts. In spite of its widespread use, a detailed experimental procedure has yet to be published. This study examined all practical aspects of pendant drop experiments with viscous polymer melts and establishes procedures for material preparation, syringe diameter selection, experimental protocol, determination of equilibrium, and the most accurate measurement of interfacial tension. In addition, the effects of both drop volume and unstable drops on interfacial tension measurements are discussed. Comparing the surface tension and interfacial tension values for several polyethylene (PE) and …  Read more

A new methodology is proposed to solve the runner balancing problem. The proposed methodology avoids problems associated with the traditional approach. The issues associated with runner balancing and the effects of design variables and processing conditions are evaluated. A general methodology for the robust optimization of a practical industrial problem is also developed. The runner balancing problem is optimized employing deterministic and robust schemes and the results were compared and analyzed. This provided insight into robust runner system design. Finally, an existing constrained genetic algorithm, the superiority of feasible points method is modified to include infeasible solutions in the search, …  Read more

In this thesis, we explore several direct detect system architectures and necessary digital signal processing (DSP) algorithm to either extend the transmission speed and reach or lower the cost and complexity. This thesis can be divided into three parts. In the first part, we focus on high throughput data transmission over 500 m to 2 km of standard single-mode fiber (SSMF) enabled by Mach Zehnder modulators (MZMs). Utilizing high order pulse amplitude modulation (PAM) format and linear and nonlinear DSP algorithm, we demonstrate a record net 300 Gbps/λ intensity modulation direct detection (IM/DD) transmission with an O-band silicon photonic (SiP) …  Read more

St-Arnaud, Rene (Supervisor2)  Read more

La réutilisation de modèle reste encore un défi majeur dans le MDE, malgréles différents succès dans les langages de programmation, illustré par des exemples tels que les bibliothèques de classe, les services, et les composants. Les modélisateurs créent généralement des modèles à partir de zéro, car les langages de modélisation offrent un support limité pour réutiliser des modèles existants; de plus, les outils de modélisation en général ne sont pas livrés avec une bibliothéque de modèles réutilisables. Mais aussi, la nature transversale des questions sur le développement des logiciels complique l'application des techniques de génie logiciel tels que cacher l'information, …  Read more

Stephanie Thibaudeau (Supervisor2)  Read more

Feldman, Liane S (Supervisor2)  Read more

Majewski, Jacek (Supervisor2)  Read more

Les connaissances mathématiques jouent un rôle majeur dans notre vie quotidienne. La littérature existante suggère que l'environnement de calcul à la maison contribue au développement des mathématiques des enfants. Cependant, ces relations sont complexes et mal comprises. La numératie à la maison peut être influencée par plusieurs facteurs implicites (comme l'anxiété des parents et des enfants face aux mathématiques) et explicites (comme jouer à des jeux de société). Certains des facteurs ont été ciblés dans des études antérieures, tandis que d'autres sont sous-examinés. En termes de technologies pour la pratique de la numératie à la maison, les outils numériques modernes …  Read more

Stephens, David (Supervisor1)  Read more

Six full-scale reinforced concrete corbel specimens were tested to study the influence of steel and polypropylene fibres, headed bars, and horizontal loading on their responses. The experimentally determined capacities were compared with predictions using simplified and refined strut-and-tie models, with the refined models providing better predictions of the capacities. The experimental study demonstrated the beneficial use of fibres in reinforced concrete corbels, that is a reduction in the number and the width of cracks at service loads. Headed bars provided excellent anchorage of the main tension tie reinforcement and eliminated the need to weld bearing plates to the reinforcement, as …  Read more

Brain organoids are three-dimensional multicellular structures capable of faithfully recapitulating the in vivo brain. Brain organoids grown from human induced pluripotent stem cells constitute promising tools for investigating mechanisms that underlie human neurodegenerative diseases and neurodevelopment. A major challenge that hinders applications of brain organoids is their lack of vasculature, which leads to cell death at their core due to insufficient delivery of oxygen and nutrients once they exceed the diffusion limits that enable oxygenation and nutrient supply. Attempts to vascularize brain organoids often include differentiation protocols performed in traditional well plates, which do not provide a straightforward method for …  Read more

The presence of vibrational and rotational transition lines in the mid-infrared (MIR) (2-10 µm) spectral range has stimulated numerous applications in the fields of spectroscopy, sensing and medicine. These emerging applications have intensified the research effort for the growth and development of novel optical light sources. Nonlinear effects in glass fibers are being extensively studied to generate ultrafast pulses at this wavelength range. Highly nonlinear silica fiber has shown record performance in the telecommunication wavelength band, however the strong material absorption of silica glass at wavelengths >2 µm limits its applicability in MIR. Recently, due to the extended MIR transmission …  Read more

Matricellular protein Cellular Communication Network 5/Wnt-1-Inducible Signaling Pathway Protein 2 (CCN5/WISP2) is a novel target of IGF-1 and WNT signaling within the pancreatic islets. Our previous works suggest that CCN5 promotes β-cell proliferation and survival via Akt/PKB and focal adhesion kinase. Recently, we reported sexually dimorphic effects of CCN5 knockout in glucose tolerance and insulin sensitivity in high-fat diet (HFD)-induced obesity, supporting a trophic role of endogenous CCN5 expression on pancreatic islets, albeit mostly in male mice.To further establish the in vivo effect of CCN5 in a gain-of-function model, we assessed aP2-CCN5 transgenic mice which overexpress CCN5 in adipose tissues. …  Read more

This thesis examines an approach to the representation of 3-D objects based on multi-scale surface patches. These patches are computed using multiple alternative decompositions of the surface based on the signs of the mean and Gaussian curvatures. The approach is applicable both to polyhedral objects as well as smoothly curved objects. A hierarchical ranking of these patches is then used to describe individual objects based on geometric information. These geometric descriptors are ranked according to several criteria expressing their estimated stability and utility. Pose estimation is cast as an optimal matching problem. The geometric pose transformation between two views of …  Read more

Osteogenesis imperfecta (OI), a heritable connective tissue disorder, often leads to long-bone deformation and bone fragility, significantly impacting daily activities. Current treatments involve bisphosphonates and surgical correction, including osteotomy and intramedullary rodding. However, post-surgical challenges such as delayed union or non-union at the osteotomy site remain, causing pain, bending of fixation rods, repeated fractures, and loss of mobility. Seeking alternative solutions, researchers have explored bone grafts and bone-marrow-derived mesenchymal stem cells (BM-MSCs) for bone regeneration, but these options have limitations. An emerging stem cell source, the autologous adipose tissue-derived stromal vascular fraction (aSVF), provides a promising alternative. aSVF comprises non-expanded …  Read more

Tewfik, Marc (Supervisor1)  Read more

Yong, R. N. (Supervisor)  Read more

The aim of this study has been to elucidate the neural pathways involved in the regulation of adrenal ornithine decarboxylase (ODC) activity. Administration of the dopamine-receptor agonists apomorphine (APM) and piribedil (PBD) to rats led to an increase in ODC activity of both the adrenal medulla and cortex. These effects were blocked by giving the animals the dopaminergic antagonist haloperidol. The APM-induced increase in adrenomedullary ODC activity was largely prevented by denervation of the adrenal, transection of the spinal cord, and transection of the mesencephalon-diencephalon. Section of ventral spinal roots reduced the induction to varying extents, depending on the number …  Read more

Feine, Jocelyne (Supervisor1)  Read more

Bedos, Christophe (Supervisor1)  Read more

A novel Amsacta moorei entomopoxvirus (AmEPV) late phosphoprotein, expressed at high levels and implicated in the formation of filamentous structures, was identified and referred to as FALPE (filament-associated late protein of entomopoxvirus). Significant homologies were found between this protein and the baculovirus protein p10. p10 is also associated with a large network of fibrous bodies produced very late in baculovirus infected insect cells. FALPE and p10 were shown to have the ability to self-associate via a coiled-coil domain found at their amino termini. Self-association of these proteins results in the formation of larger aggregates which constitute the building blocks of …  Read more

Fackson Mwale (Supervisor1)  Read more

Les ARN non codants (ARNnc) ont suscité l’intérêt croissant des chercheurs ces dernières années. Chez l'homme, 68% de ces ARNnc sont des ARN longs non codants (ARNlnc) pouvant atteindre 200 nucléotides ou plus. Cependant, la fonction de la majorité des ARNlnc demeure inconnue. Le rôle et la présence des ARNlnc ont été rapportées dans plusieurs maladies, notamment le cancer, mais on en sait peu sur leur implication dans la fonction des cellules endothéliales (CE) et l'angiogenèse. En 2014, nous avons démontré, pour la première fois, l’expression des ARNlnc dans des cellules endothéliales humaines. Il a été rapporté qu’environ 56% de …  Read more

Les personnes souffrant d’amblyopie démontrent une capacité réduite à juger la profondeur en utilisant la stéréoscopie. Les tests stéréoscopiques cliniques existants ne sont pas suffisamment sensibles pour mesurer les fonctions stéréoscopiques résiduelles chez les amblyopes et limitent notre compréhension de ce déficit. Cette étude présente un test de stéréoscopie pour quantifier la stéréoacuité réduite. Une cible en profondeur définie par la disparité est présentée sur un champ de points aléatoires. Les participants identifient l'emplacement de la cible tout en portant des lunettes 3D actives. Nous avons utilisé la méthode de bruit équivalent afin d’évaluer le rôle de l’efficacité de traitement …  Read more

Having a complete knowledge about average traffic rates on different links in a network is highly desirable for network operators, particularly when performing tasks such as capacity planning and traffic engineering, or when making decisions on network redesigning.In this thesis, we propose a technique for estimating the average downlink traffic rate on internal links from a single measurement point. Our main contribution is a solution that does not assume a specific statistical model for the traffic, relying only on a constant ratio between the uplink and the downlink traffic on each link, and a constant proportion of traffic that goes …  Read more

Introduction: L'injection intra-glandulaire de toxine botulinique est un outil important dans le traitement de la sialorrhée grâce à une dénervation transitoire de la glande salivaire. L'objectif de cette étude est de déterminer l'effet à long terme de l'administration répétée de la Toxine Botulinique A (Onabotulinum toxin A) sur le poids et le volume de la glande parotidienne des gerboises. Méthode: Après nombreuses procédures, un modèle animal a été développé. Quinze gerboises ont été aléatoirement assignées à 3 groupes, chaque groupe étant constitué de 5 animaux. Le groupe 1 a reçu 3 injections, le groupe 2 a reçu 5 injections et …  Read more

The formation of nitrates in soil, under favourable conditions as to moisture, temperature, and aeration is a reaction well known and frequently studied. The bodies yielding nitric acid in the soil are, firstly, the various nitrogenous organic substances which arise from the decay of vegetable or animal matter; and secondly, ammonium salts, either produced in small quantity during the decay of organic matter, or carried to the soil by rain, or in some cases, applied as fertilizers. A further source of the nitrates contained in the soil is to be found in the free nitrogen of the atmosphere, but of …  Read more

Under natural conditions, cellulose is biochemically one of the most important compounds to reach the soil by means of plant residues. This is especially true of forest soils and pastures. In agricultural soils, under crops, the normal equilibrium between groups of microorganisms is slightly displaced by the introduction of plant residues and by the addition of manure. There is also a large addition of cellulose and,at the same time, other reserve material from plowing in the roots of annual crops. In normal soils, cellulose becomes decomposed under the combined action of fungi and aerobic bacteria. Of these two groups of …  Read more

Ce mémoire de maîtrise se consacre à l'étude des formes de brouillage dans la littérature française de l'extrême-contemporain de 2005 à 2015. Par brouillage, nous entendons les divers moyens mis en œuvre pour faire éclore, entretenir et perpétuer la confusion. C'est aux Éditions de Minuit que cette propension au mélange délibéré se déploie le plus radicalement : la prestigieuse maison d'édition, associée aux Nouveaux Romanciers, rapatrie le récit que ces derniers avaient conspué, mais se refuse à le laisser intact. À une remise en cause du roman traditionnel, les écrivains contemporains de chez Minuit, alimentant le flou, font se succéder …  Read more

Depuis plusieurs années, on note un intérêt marqué dans les médias pour les femmes entretenant des relations de nature intime avec des hommes plus jeunes qu'elles. Communément appelées « cougars », ces femmes sont présentées comme défiant les normes de genre traditionnelles en matière de sexualité et de relations intimes. Elles sont souvent imaginées comme ayant un grand appétit sexuel, comme étant entreprenantes en matière de de séduction et comme recherchant de brèves aventures. Cependant, il existe à ce jour très peu d'études au sujet de l'expérience des femmes ayant des relations intimes hypogamiques en termes d'âge. La question de …  Read more

La préconcentration d'échantillons liquides et l'analyse de métaux au niveau de traces dans une matrice minérale très stable a été réalisée en utilisant des fours à graphite (FG) accouplés à un plasma à couplage inductif. Plusieurs éléments réfractaires ont été évalués directement dans une matrice de zéolite en utilisant un four au graphite modifié de façon à permettre l'emploi d'un melange gazeux argon/fréon. L'échantillon de zéolite a été déposé dans le tube de graphite sous forme de suspension et une digestion complète de la matrice minérale a été obtenué par formation d'halogénures.[...]  Read more

This thesis summarizes our work on the entanglement entropy of cosmological perturbations. The purpose of this work is to connect and build upon progress in momentum space entanglement in quantum field theory, open quantum cosmological systems, the decoherence of primordial fluctuations in the early universe and the entropy of gravitational perturbations arising from a squeezed super-Hubble vacuum state. We discuss the origin of this entropy from gravitational nonlinearities and mode-couplings arising from quantum vacuum fluctuations. We demonstrate that the entropy of scalar cosmological perturbations can be viewed as momentum space entanglement entropy between sub- and super-Hubble modes. We calculate this …  Read more

A review of the literature indicates a facilitative effect of emotional content on communicative abilities in aphasia, including discourse production (e.g., Bloom, Borod, Obler, & Gerstman, 1992; Bloom, Borod, Santschi-Haywood, Pick, & Obler, 1996; Landis, Graves, & Goodglass, 1982; Ramsberger, 1979; Reuterskioeld, 1991). To explore how emotional content influences discourse-level pragmatic features in narratives produced by Arabic-speaking adults with aphasia, Grice's (1975) pragmatic framework for discourse analysis was adopted. The primary question addressed by the current study was whether or not discourse elicited using stimuli with emotional content (positive or negative) is superior in quantity, quality, relevance, and manner than …  Read more

Fackson Mwale (Supervisor1)  Read more

The objective of this research was to investigate the effect of heating on α-Tocopherol content and antioxidant activity of different vegetable oils (EVOO, canola and palm oil). The highest α-Tocopherol content was found in EVOO followed by canola oil and palm oil (323 ±5, 271 ±2 and 174 ±2 µg/ml) respectively. The effect of heat was done at 70, 100 and 130 oC, for time intervals of 0.5, 1, 1.5 and 2 h. Thermal degradation of α-Tocopherol in the oils was minimal at 70 oC and increased at 100 oC and 130 oC. Heating at 130 oC for 2 h …  Read more

Ce mémoire explore la façon dont d’Yaḥyā ibn ‘Adī traite le problème de la prescience divine. Yaḥyā était un théologien et philosophe né en 893 ap. J.-C. dans une famille de Chrétiens Syriaques en Tikrit, Irak. Après avoir déménagé à Bagdad - à ce moment la capitale culturelle et intellectuelle florissante de l’empire Abbaside. Yaḥyā étudia auprès du maître des péripatéticiens de Bagdad, Abū Bishr ibn Mattā (d. 940 ap. J.-C.), et aux cotés du philosophe et logicien musulman influent, al-Fārābī. Son traité, Risāla fī Ithbāt Ṭabī‘at al-Mumkin [Traité sur l’affirmation de la nature du contingent], constitue le texte où …  Read more

The present study was designed to investigate gender differences in the fragility of children's close, same-sex friendships. Based on past research, it was hypothesized that the close friendships of girls are more fragile than those of boys. A secondary goal of the study was to explore possible reasons for the sex difference in friendship instability. Students from 17 classes of grades one through six of an elementary school were interviewed about past friendships, and conflict resolution among current friends, within their class. The hypothesis that girls' friendships are more fragile was supported: The number of past friendship reported for girls …  Read more

Caulobacter crescentus is a well-established model for studying the bacterial cell cycle, a complex process where the stages of growth, chromosome replication, and cell division often overlap, highlighting the presence of a highly coordinated regulatory network that remains partially understood. To search for novel regulators of the cell cycle, specifically of chromosomal replication, we developed a novel molecular screen to isolate dipM-like mutants. DipM is an endopeptidase and a cell division protein that was implicated in the coordination of DNA replication and cell division by our group. We believe that by generating Caulobacter mutants and selecting dipM-like phenotypes, it is …  Read more

The absence of a class action mechanism in a legal system hinders access to justice for individuals with similar claims, as it forces them to pursue costly and time-consuming litigation independently. This duplication of efforts burdens courts with repetitive adjudication of nearly identical issues, potentially leading to inconsistent judgments. To address these challenges and improve access to justice, this thesis explores the feasibility and potential benefits of introducing class actions into the Kuwaiti legal system, drawing on the Canadian class action model, particularly the frameworks in Quebec and Ontario. In doing so, the thesis addresses key questions such as whether …  Read more

Leask, Richard L. (Internal/Cosupervisor2)  Read more

This thesis is a step forward in evaluating insulin therapy and defining its role in cardiac surgery first described as Glucose-Insulin-Potassium (GIK) solution 40 years ago. Chapter (I) includes a review of the literature on insulin therapy in cardiac surgery and illustrates the scientific bases and controversies in this therapy. Chapter (II) entitled: "Myocardial Protection During Elective Coronary Artery Bypass Grafting Using High Dose Insulin Therapy" represents a manuscript that was presented in the following meetings: (A) Local meetings: (1) McGill cardiovascular research day, February 1/2007, Montreal, Canada. (2) Fraser Gurd annual research day, McGill surgery department, May 31/2007, Montreal, …  Read more

Janda, Richard (Supervisor)  Read more

NOD.B6 Idd3 congenic mice, whose Idd3 locus originates from the autoimmune resistant C57BL/6 mouse, demonstrate a drastic reduction in diabetes onset. In this study we demonstrate that NOD.B6 Idd3 mice show halted disease progression and also show reduced levels of TH1 cells in their peripheral immune system. In vitro , CD4+ CD25- effector T (TEFF ) cells from congenic mice display increased proliferation and IL-2 production compared to wild type NOD mice. However, unfractionated NOD.B6 Idd3 CD4+ T cells maintain a higher TREG:T EFF ratio and proliferate less than their NOD counterparts, suggesting increased immunoregulation. In vivo, the Idd3 locus …  Read more

The mechanisms underlying the pathogenesis of aortic valve calcification remain unclear. With accumulating evidence demonstrating that valve calcification recapitulates bone development, the crucial roles of non-canonical Wnt ligands Wnt5b and Wnt11 in osteogenesis make them critical targets in the study of aortic valve calcification. We hypothesized that Wnt signaling mediated by ligands Wnt5b and Wnt11 is upregulated and the expression of these molecules may be associated with the pathological calcium deposition in aortic valves. We examined Wnt5b and Wnt11 protein expression in 75 mitral, non-calcified and calcified aortic valves by immunohistochemistry. There was little expression of Wnt11 or Wnt5b in …  Read more