McGill University Thèses et mémoires par auteur commençant par T

This thesis is a descriptive study of the post-release employment experiences of forty five English-Speaking male parolees in the greater Montreal Area. The objective of this study was to examine various aspects of the parolees' employment experiences, as well as to describe some of the social characteristics which might be related to employment functioning. [...]  Lire la suite

One-, two- and three-dimensional transient heat transfer finite element models are developed to simulate the resistance welding process of pre-consolidated unidirectional AS4 carbon fibre reinforced Poly-ether-ether-ketone (APC-2/AS4) laminates with a metal mesh heating element, in a lap-shear configuration. The finite element models are used to investigate the effect of process and material parameters on the thermal behaviour of the coupon size welds, yielding to a better understanding of the process. The 1-D model determines: (a) the importance of including the latent heat of PEEK, and (b) the through-thickness temperature gradient away from the edges, for different tooling plate materials. The …  Lire la suite

Les tourbières sont une composante importante du cycle global du carbone, séquestrant le tiers du carbone contenu dans les sols. L'accumulation de la tourbe dépend de deux facteurs principaux: l'hydrologie et la végétation. Des études ont abordé l'impact d'un abaissement de la nappe phréatique sur les flux de carbone des tourbières. Cependant, l'échelle temporelle de ces études ne permet pas de voir de changements de végétation en réponse à un abaissement de la nappe phréatique. Pour être en mesure de prédire le futur des tourbières dans un climat potentiellement plus sec, les effets des changements de végétation doivent êtres considérés. …  Lire la suite

Early 1960's meander rectification of the Ste-Marguerite River, Quebec, Canada, was undertaken in order to facilitate highway construction along the valley bottom. Through analysis of thalweg elevation and grain size data, the fourfold response of the river since rectification has been determined: (1) 1 m of bed incision in the upper 4 km and 2m of bed aggradation in the lower 2 km of the 6 km straightened reach; (2) coarsening (up to 20 mm) of the pavement D50 and D84 in the area of maximum degradation; (3) lateral erosion of the channel into three high terraces; and (4) regrowth …  Lire la suite

Afilalo, Jonathan (Internal/Supervisor)  Lire la suite

Afin de prétendre que les comportements des neurones du cortex visuel sont pleinement compris, il doit être possible de créer des modèles de ceux-ci qui peuvent entièrement prédire leurs réponses à tout type arbitraire de stimuli. Le thème sous-jacent de cette thèse est donc d'explorer les stimuli et les approches d'identification de système appropriés pour l'estimation de tels modèles de champ récepteur (CR), ainsi que d'examiner de façon quantitative les propriétés de leur réponse. Plus précisément, je cherche à répondre aux questions suivantes: 1) quels types de stimuli donnent des modèles de CR les plus robustes et généralisables?; 2) est-ce …  Lire la suite

Papadopoulos, E. (Supervisor)  Lire la suite

Goad, Heather (Supervisor)  Lire la suite

Rousseau, Cecile (Supervisor)  Lire la suite

Cell migration is essential in a number of biological processes such as tissue and organ development, immune responses, and cancer metastasis. It involves a complex spatial and temporal regulation of the formation and disassembly of adhesive patches, called focal adhesions that adhere the cell to its substrate. Adhesions must form at the front of the cell securing it to the substrate so it can be pulled forward while adhesions at the rear disassemble or detach allowing the cell to process forward.ShcA is an adapter protein that's indispensable for ErbB2-dependent increases in cell migration, invasion and metastasis, in response to TGFβ-growth …  Lire la suite

Scaffolding proteins control the localization of protein kinases. During translation, the scaffolding proteins eIF4G and DAP5 recruit the Ser/Thr kinase Mnk1 to phosphorylate the mRNA cap-binding protein eIF4E and modulate translation. Biochemical deletion analysis previously showed that the interaction between Mnk1 and eIF4G/DAP5 is mediated by N-terminal residues in Mnk1 and C-terminal residues in eIF4G/DAP5. Using X-ray crystallography I have determined the structure (1.5 A) of the C-terminal domain of DAP5 (DAP5C). This structure reveals that DAP5C contains two atypical HEAT domains similar to the ones seen previously in the structure of the C-terminal region of eIF4G (4GC). Using ITC …  Lire la suite

In a referendum held on the 10th of May 1972, the Republic of Ireland voted to join the European Economic Community in overwhelming fashion. With turnout as high as 70.9 percent, the ‘Yes’ campaign managed an impressive 83.1 percent of the total vote. Such high levels of enthusiasm for EEC membership, which would remain unmatched for decades, hint at an Irish vision of Europe as a place for economic development, stability, and positive cultural exchange. This vision was the result of a long process of identity formation in Ireland which goes back before even Irish independence. Beginning with the formation …  Lire la suite

Les cellules tueuses naturelles (Natural Killer [NK]) sont parmi les premières cellules qui répondent aux infections virales et servent de lien entre les systèmes immunitaires innés et acquis. Une activité plus accrue des cellules NK a été observée chez les individus classés comme séronégatifs exposés au VIH (HIV Exposed SeroNegative [HESN]). La réponse fonctionnelle de ces cellules est déterminée par l'intégration des signaux activateurs et inhibiteurs transmis à la cellule NK par les récepteurs de surface. La famille des récepteurs KIR (Killer Immunoglobulin-like Receptor) comprend neuf récepteurs inhibiteurs, six récepteurs activateurs et deux récepteurs non exprimés encodés par des pseudogènes. …  Lire la suite

Schizophrenia is a complex neuropsychiatric disorder affecting roughly 1% of the population, making it a significant public health concern [Sawa and Snyder, 2002]. Presentation of schizophrenia includes positive (hallucinations, delusions) and negative (lack of motivation, inability to feel pleasure) symptoms, in addition to cognitive impairments [Owen et al., 2016]. However, both symptom burden and associated brain alterations are highly heterogeneous and intimately linked to prognosis. To characterize the clinical heterogeneities, there is a need to develop methods that can predict symptom burden at the individual level. To serve this purpose, machine learning algorithms were implemented to first derive clinical subgroups …  Lire la suite

Duma pro Slipykh is a composition for solo baritone, 12-part mixed choir and small chamber orchestra, lasting approximately 17 minutes and 30 seconds. The work sets excerpts from two Ukrainian poems: Mykola Bazhan's Sliptsi (1929) and Wolodymyr Tsybul'ko's Yanholy i Vovky (1996). Excerpts from both poems were layered in various ways to form the text of the piece. The simultaneous performance of multiple excerpts with common elements and themes was devised to emulate the frenetic energy and angry frustration the poets were trying to express in their poems. Although nearly seventy years separate the two poems, the general themes of …  Lire la suite

Queezinart---hocket in a blender is a composition for five woodwinds, five brass, percussion (two players), piano, two violins, viola, cello and double bass, with a duration of approximately 14 minutes. There are six main sections in this piece. The work is structured so that musical ideas flow smoothly and gradually between sections. Also, the musical events are organized in such a way that the perceived, experienced time is manipulated and distorted, through varying activity and density of musical events.  Lire la suite

Waugh, W. (Supervisors)  Lire la suite

Dans la plupart des codes de construction nationaux, la classification des sites est basée sur le paramètre Vs30, la vitesse moyenne des ondes de cisaillement jusqu’à une profondeur de 30 m en dessous de la surface, et définit les facteurs de fondation (Fa et Fv) appliqués aux mouvements de référence. Un microzonage sismique délimite une règion en fonction des types de sols et est généralement obtenu en combinant l’information provenant de diverses sources, chacune ayant un degré d'incertitude variable. Un microzonage préliminaire peut être dérivé à partir des cartes de la géologie de la surface ou des cartes de l'élévation …  Lire la suite

The study of the clay colloids of soils was initiated by Schloesing (46), who in 1870-74, separated, what he termed colloidal clay from French soils. He accomplished this by triturating the soil in the presence of water, decanting the supernatant and then permitting the clay particles to settle out. The material which remained in suspension after 24 hours settling, he designated clay colloid. It comprised 1.5$ of the weight of the whole soil and was thought by Schloesing to be amorphous in nature.[...]  Lire la suite

Breitner, John (Supervisor2)  Lire la suite

Impaired wound healing leads to major medical problems such as chronic ulcers and tissue fibrosis. As transforming growth factor-beta (TGF-beta) is an important regulator of cutaneous wound repair, modulation of TGF-beta's function represents a potential means of therapeutically modifying the healing process. In order to understand TGF-beta's action in the skin, it is important to characterize TGF-beta receptor profiles and the formation of oligomeric receptor complexes in human skin cells. TGF-beta signals through the types I and II receptor kinases, while the type III receptor facilitates ligand binding to the types I and II. Our results show that human dermal …  Lire la suite

Breast cancer is the most common type of cancer diagnosed in Canadian women, with metastatic spread contributing to the majority of cancer-related deaths. The liver is the third most frequent site of breast cancer metastasis, but not much is known about the hepatic microenvironment's role in regulating the growth and survival of metastatic cells in the liver. In order to elucidate these interactions, we used laser capture microdissection and microarray analysis to compare gene expression patterns of liver metastases and primary tumors. We employed liver-aggressive 4T1 breast cancer cells derived from an in vivo selection process to generate mammary tumors …  Lire la suite

On 18 June 2002, the anomalous X-ray pulsar 1E 2259+586 underwent a major X-ray outburst that lasted several hours and consequently linked AXPs to the class of magnetar-candidates known as soft gamma repeaters (SGRs). Three days after the outburst, observations with the Gemini Observatory showed a near-infrared flux enhancement, presumably associated with the X-ray activity. We have since performed a ~1.5 year monitoring program of the Ks band (2.5 mum) photometry, and find that the flux decreased continually, reaching its pre-burst level after about one year. Comparing both the near-IR flux increase and subsequent decay to those of the X-ray …  Lire la suite

Multi-path routing algorithms in packet-switched computer networks have the potential for achieving high throughput and low average packet delay by making use of several paths to route data from a source to a destination. In this thesis, we investigate a multi-path algorithm proposed by Gallager (GALL77) which, given continuously differentiable link flows, has been proven to generate "optimal" routes in a quasi-static environment. However, the performance of the algorithm in a realistic environment has not been established. We show that the Count-to-Infinity problem is inherent in this algorithm and we describe a method of dealing with it. Employing two separate …  Lire la suite

The wide accessibility and low cost of virtual reality (VR) on the Web with the advent of the Virtual Reality Modelling Language (VRML) and VRML interpreters makes it ideal for use in providing cost-effective training for operators in selected complex technical environments. VR using VRML is limited; it is not suitable for all types of training, and the cost-effectiveness of deploying VRML-based virtual environments (VEs) is often impeded by high development time and cost. This thesis examines the potential of using VRML to implement VEs for training in suitable tasks, and demonstrates that this potential can be fulfilled using an …  Lire la suite

Le rôle du récepteur orphelin relié aux estrogènes (ERRα) dans le cancer du sein a été étudié avec un intérêt grandissant au cours des dernières années. Cependant, les études de génomique fonctionnelles appliquées à ERRα ont jusqu’à maintenant été restreintes aux lignées cellulaires, alors que de nombreuses évidences ont démontré que certains récepteurs nucléaires jouent des rôles distincts dans les tumeurs comparativement aux lignées cellulaires. L’objectif de cette étude était donc de déterminer les voies de signalisation transcriptionnelles régulées par ERRα dans les tumeurs du sein. À cette fin, nous avons utilisé la technique de la précipitation de chromatine suivie …  Lire la suite

The fusion (F) protein of measles virus is responsible for viral penetration at the plasma membrane and syncytia formation. In order to facilitate future structure/function studies, the F protein was expressed in insect cells using recombinant baculovirus, and in mammalian cells using both vaccinia and adenovirus recombinants. The baculovirus system exhibited the highest levels of recombinant protein expression, but the majority of the product was found to be in the form of detergent-insoluble precursors. Replacing the signal peptide of the F protein with insect-derived sequences did not enhance posttranslational processing. Also, expression of truncated, anchor-minus forms of the F protein …  Lire la suite

The majority of individuals with .long-term diabetes become afflicted with diabetic peripheral neuropathy (DPN), an often painful and debilitating secondary complication of the disease. Symptomatic treatments, which do not address the underlying nerve damage in diabetes, are currently the only therapeutic options for DPN, aside from rigorous control of blood glucose, which only occasionally reduces the incidence and severity of DPN. Given the progressive nature of disorder, and the failure of the classical neurotrophins in clinical trials for DPN, it is important to develop new therapeutics that can counteract the nerve damage in diabetes. Pancreas-derived peptides that stimulate islet regeneration …  Lire la suite

Metal and acid containing effluents generated by industry are most commonly treated with lime which neutralizes the acid and precipitates the dissolved metals. The resulting sludge contains gypsum which has a high water content and requires large landfill volumes. It is therefore desirable to find a neutralizing agent which has a good neutralizing capacity and a dense precipitate which can be easily dewatered at low cost. A dense, fast settling sludge would also reduce the cost of the process and the volume to be landfilled. Magnesium hydroxide has been examined in this research as a neutralizing agent for a simulated …  Lire la suite

The removal of multiple substrates in a defined mixed culture process was investigated in the treatment of brewery wastewater. The study was conducted using both batch and a semi-continuous reactor system called self-cycling fermentation. Batch experiments were conducted using a synthetic brewery wastewater containing glucose, ethanol and maltose. Activated sludge from a municipal wastewater treatment plant was acclimatized in the synthetic brewery wastewater. The microbes capable of degrading this wastewater were analyzed by a combination of microscopy, spread plating, and Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis (PCR-DGGE) and identified as Acinetobacter sp., Enterobacter sp. and Candida sp. From the pure …  Lire la suite

Six exterior-column Slabs of identical sizes and with the identical amounts of longitudinal slab reinforcement and concrete strength and with varying column sections were tested to failure under varying eccentricity of load for the study of the ultimate shearing strength of the slab. The moment reduction factor K, determined by experimental method, was found to be mainly dependent upon the dimensions of the specimens examined. The results gave an average value of the ultimate shear stress of 458 psi., namely 0.1 f'c• which is approximately equal to the tensile trength of concrete. The results were compared with code requirements as …  Lire la suite

The interferon (IFN)-inducible protein kinase PKR is thought to mediate the biological effects of IFNs through its ability to phosphorylate eukaryotic initiation factor 2 and to inhibit protein synthesis. Additional reports have implicated PKR in transcriptional regulation. In this study, a role for PKR in the regulation of signal transduction pathways that are required for IFN action was examined. It is demonstrated that PKR negatively regulates signaling pathways induced by IFNs and dsRNA. This regulatory effect is attributed to a protein-protein interaction between PKR and STAT1, the signaling component common to these pathways, that impairs STAT1 transcriptional function. The interaction …  Lire la suite

One of the underexplored opportunities in personalized medicine is the precise control of the timing of drug delivery to sync with an individual’s biological rhythms for maximum effectiveness. The clinical status quo is drug formulations for slow, sustained release but many treatments require precise, pulsatile and repeated dosing. To this end, nanomaterials that can release drug triggered by an external stimulus are advantageous.Upconverting nanoparticles (UCNPs) are near-infrared (NIR) to ultraviolet (UV) transducers that can be used for NIR-controlled drug delivery. By coating the UCNP surface with polymer or silica drug carriers that respond to UV, one can achieve drug release …  Lire la suite

Mucopolysaccharidase-producing oral bacteria may contribute to the pathogenesis of inflammatory periodontal disease in several ways. Bacterial mucopolysaccharidases, in the area of the gingival crevice, can destroy important components of the ground substance of connective tissue leading to periodontal destruction on the one hand and enhancing the spread of bacterial toxins on the other. Partial breakdown of proteoglycan due to penetration of small amounts of these enzymes may also expose cryptic antigenic determinants, resulting in destructive autoimmune reactions. Finally, mucopolysaccharidase-producing oral bacteria may interact symbiotically with other pathogens of the gingival sulcus by enzymatic breakdown of tissue to release fermentable substrates …  Lire la suite

Schistosoma est une des espèces les plus complexes de parasites humains. Il est dioïque et requiert un cycle de vie indirect : un hôte intermédiaire, l'escargot, et un hôte définitif, l'homme. Le système nerveux du parasite contrôle le comportement et toutes les activités physiologiques importantes et est en grande partie responsable de la complexité du cycle de vie du parasite. La signalisation neuronale des schistosomes est médiée par une variété de neurotransmetteurs et récepteurs correspondants, dont la dopamine et le glutamate. Ces transmetteurs régissent en partie les fonctions neuromusculaires et le mouvement, mais leur mode d'action demeure inconnu. Cette étude …  Lire la suite

Urban agriculture demands sustainable substrates that support plant growth while minimizing environmental impact. This study evaluated a biocompatible porous concrete (PC) formulated with ground granulated blast furnace slag and quartz aggregate as a dual-function material for hydroponic cultivation and water filtration. The research examined (i) its filtration and nutrient leaching behaviour, and (ii) plant growth and nutrient uptake of red Russian kale (Brassica oleracea var. acephala) compared with commercial rockwool under nutrient film technique (NFT) hydroponics.Filtration experiments demonstrated that porous concrete effectively retained suspended solids and selectively absorbed dissolved nutrients, followed by gradual release over successive cycles, consistent with buffering …  Lire la suite

A new testing paradigm called Built-In Self-Test (BIST) has been gaining increasing acceptance over the traditional automatic test pattern generation for testing the current complex integrated circuits. The basic idea in BIST is to integrate the design with test functionalities like pattern generation, response analysis, and test control. Of the various schemes, pseudo-random pattern testing is an attractive technique for BIST because of the simple hardware required for on-chip test pattern generation. Besides, structures for pseudo-random pattern generation like linear feedback shift register (LFSR) or cellular automata (CA) can also be utilized for on-chip response analysis. In general, pseudo-random BIST …  Lire la suite

L'acylation de mono- et oligosaccharides catalysée par des hydrolases d'esters carboxyliques dans des milieux non conventionnels a été explorée, et ce dans le but de synthétiser des composés ayant de potentielles propriétés bioactives complémentaires. Deux préparations de FAE (EC 3.1.1.73) de Humicola insolens ont été évaluées pour leur spécificité vis-à-vis le substrat et leur activité enzymatique, en utilisant des saccharides feruloylés soit synthétiques soit isolés à partir de son de blé et de betterave sucrière, l'un d'entre eux présentant une activité plus élevée et une spécificité plus large parmi les substrats testés. Cet enzyme a ensuite été sélectionné pour évaluer …  Lire la suite

Le développement des tumeurs cérébrales est mal compris. Le médulloblastome (MB) est la tumeur maligne pédiatrique la plus fréquente et un de ses sous-groupes présente une dérégulation de la voie de signalisation hedgehog (SHH-MB). Une mutation du récepteur PTCH1, qui lie le ligand sonic hedgehog et agit comme suppresseur de tumeur, est la mutation induisant le développement du MB la plus fréquente. En se basant sur le modèle murin PTCH1+/- du MB, il a été proposé que le MB était un modèle de cancer « two-hit » où la perte du premier allèle entraine le développement d’une lésion prénéoplasique et …  Lire la suite

Au cours des dernières années, la photonique sur silicium a suscité un vif intérêt de la part des chercheurs ainsi que de l'industrie en raison de sa compatibilité avec la technologie CMOS, une plateforme mature qui permet une production à faible coût et à grand volume. Dans la littérature récente, de nombreux dispositifs - actifs et passifs - ont été intégrés sur la plate-forme silicium sur isolant (SOI). Des sous-systèmes comprenant plusieurs composants ont aussi été intégrés sur une seule puce en silicium afin de réaliser un système complet (par exemple, un récepteur cohérent).En parallèle, la demande de capacité toujours …  Lire la suite

The work in this thesis demonstrates whether resins are better than conventional soil extractants at predicting plant metal concentrations, and whether low-cost soil treatments can effectively reduce metal content and concentrations in lettuce leaves. Researchers have shown that ion exchange resins can simulate root metal uptake behaviour by acting as ion sinks. Chemical extractants on the other hand, generally do not behave in this manner. Thus, we would expect resins (in either bead or membrane form) to predict plant metal concentrations better than conventional extractants. For the first study, a procedure using anion exchange resin membranes (AEM) treated with either …  Lire la suite

The standardized patient is one method which can be used in the measurement of clinical competence. The accuracy of reproduction of important features of the patient case by the standardized patient was evaluated in Studies 1 and 2. In 839 encounters reviewed, only 13/89 patients provided an accurate reproduction of the case. Attributes of the patient, training process and evaluation procedure were associated with better patient accuracy. A significant inverse relationship was found between patient accuracy and competence score. In Study 3, the use of standardized patients as raters of behaviour was assessed. There were systematic differences in the scoring …  Lire la suite