McGill University Theses and dissertations by author name (Ç)

The tables describing the geometry of the yield surface are derived. They concern only fcc metals which undergo isotropic hardening, and which glide on the 24 {111} slip systems. The tables list all five dimensional vertices, and edges of the fourth, third and second order limiting the yield surface as well as the slip systems with which they are associated. A direct method for calculating the yield vectors for any orientation, in five dimensional stress space is established, which enables the user to obtain the yield surface without need of knowing the six deviator stress components. The relaxed constraint theory, …  Read more

Economic downturns are known to affect the management of natural resources and the environment. Although statistics and industry figures have revealed some impacts of the 2007-08 Global Financial Crisis (GFC), its dynamics and long term consequences for forest management, particularly in the context of South America, are unknown. Using qualitative research methods, combining grounded theory and case study analysis, this research aimed to better understand how the GFC impacted sustainable forest management (SFM) in Brazil through the experiences and perceptions of highly knowledgeable stakeholders. This was done with a view to providing a more holistic and integrated perspective on the …  Read more

Great importance is currently being given to any type of ecosystem; the tropical forest is one of them and it is our case. Also, in the same way, importance is given to ecosystems inhabitants, which in one or another manner depend of the ecosystems and for many years have demonstrated a harmonious relation with their environment. In consequence, this thesis in its first chapter describes relevant issues of human communities that have lived for many years in the tropical forest located in the Darien province in the Republic of Panama. These communities are of the Embera and Wounaan indigenous groups. …  Read more

Poschke, Markus (Supervisor1)  Read more

An adequate definition of stability for linear, discrete time, invariant, infinite order systems, and factorization properties in the corresponding space of transfer functions, lead to the design of finite order robust controllers. Moreover, this class of controllers is shown to stabilize stochastic systems. The stabilization by a class of robust adaptive controllers, of non-necessarily minimum phase stochastic linear systems (with possibly unknown or heterogeneous delay) is proved. The plants considered may be slowly time varying. Simulations permit to emphasize the interest of our approach. Compared with the standard Recursive Least Squares and Stochastic Gradient Algorithms, the algorithm we introduce, is …  Read more

We examined how fast- and slow-growing families (based on height at 10 years) of Pinus banksiana Lamb. are affected by a climate altered by CO$ sb2$ during their first growing season. Our primary objective was to evaluate the possibility that genotypes performing best under present conditions may not necessarily do best under projected warmer climate. Seedlings were grown for six months in two climatic environments (350 $ mu$L/L CO$ sb2$ x present temperatures and 700 $ mu$L/L CO$ sb2$ x 4$ sp circ$C warmer temperatures) and with 100 ppm and 5 ppm nitrogen. The CO$ sb2$T$ sp circ$ environment had …  Read more

More intensive production of hogs and cattle in Quebec during the past decade has benefited local economies, but led to over-fertilization of agricultural soils and eutrophication of waterways. Provincial ministries responded to this issue by developing regulations to control manure applications. The objective of this thesis was to determine the environmental risk associated with applying farm manure in the late fall. Spreading manure in fall after harvesting corn was a common practice for many agricultural producers in Quebec, but this period is now viewed as very risky, having more negative environmental consequences than other manure application periods. This two-year study …  Read more

Serological and chemical methods were used to study the antigenic constituents of enterococci. Lancefield and Fuller extracts of eight enterococcus strains, representing four species, were investigated in double diffusion in agar for antigenic pattern and relationship. Cell fractions of S. faecalis were examined for antigenic components by latex agglutination, passive hem agglutination and double diffusion. A group specific antigen was demonstrated in a cytoplasmic fraction. The isolated and partially purified antigen was analyzed chromatographically and electrophoretically. Cell wall components of representative strains were isolated by different methods and analyzed serologically and by paper and thin layer chromatography. Hexosamine, D(+) glucose …  Read more

L'objectif de cette étude de maitrise était de quantifier les effets d'ajouter du poids sur le tronc corporel sur les adaptations de la posture et du mouvement de jeunes adultes en santé durant la fatigue induite par des mouvements répétitifs du bras. Des données cinématiques, cinétiques et électromyographiques (EMG) ont été enregistrées durant une tâche de pointage répétitif (TPR) en condition normale et avec une charge additionnelle de 20% du poids corporel. Les premières et dernières minutes de la TRP ont été analysées pour les deux séances. Les résultats démontrent que la TRP a été efficace à induire de la …  Read more

During metazoan development, it is crucial that newly formed tissues become and remain physically separate from other tissues. Four major models have been proposed to describe the cellular mechanisms governing tissue separation, including differential adhesion, differential cortical tension, contact inhibition or selective adhesion. While differences in adhesion or in cortical tension can in principle cause sorting, experimental support largely comes from artificial systems, and convincing evidence using actual embryonic cells is limited. The goal of this project was to systematically test the potential contribution of cell-cell adhesion levels, cortical myosin contractility, cell-cell detachments and expression of unique cell adhesion molecules …  Read more

Delivery of soluble lysosomal proteins from the Golgi apparatus to the lysosomes is dependent primarily on the mannose 6-phosphate receptor (M6PR). The M6PR has been demonstrated to achieve and be recycled from the endosomal compartment through interactions with GGA, AP-1, and retromer adaptor proteins. However, in I-cell disease (ICD), in which the M6PR pathway is non-functional, many soluble lysosomal proteins continue to traffic to the lysosomes. The novel sortilin sorting receptor has been implicated in the M6PR-independent targeting of sphingolipid activator proteins. We therefore tested the hypothesis that soluble proteases that exhibit M6PR-independent trafficking are targeted to the lysosomes by …  Read more

This thesis proposes to lay some of the groundwork for an investigation of the prepositional deficit in aphasia. We observe that (i) the status of the category PREPOSITION is problematic for linguistic theory and (ii) patterns of loss in aphasia do not affect prepositions uniformly. In accordance with the view that such sets of theoretical and aphasiological observations can and must be related, an overview of the structural (linguistic) properties of prepositions, an examination of a compatible sentence processing (psycholinguistic) model, and an exhaustive review of the literature on prepositions and aphasia were undertaken. A set of refined predictive hypotheses …  Read more

In this manuscript we discuss several aspects of conformally covariant operators from a spectral theory point of view. We consider operators acting on sections of a bundle or on scalar functions. For operators that are elliptic and formally self-adjoint we obtain results on the continuity and multiplicity of their eigenvalues. In particular, we prove that the eigenvalues of the GJMS operators are continuous and simple for a residual set of metrics. We also introduce several new conformal invariants that arise from considering eigenvalues and nodal sets of null-eigenvectors. As an application of our results we address a scalar curvature prescription …  Read more

On-line ultrasonic monitoring of injection molding of polyethylene and die casting of aluminum is studied using pulse-echo techniques. The flow front of molten materials including the polymers and aluminum inside the mold has been probed by a multiple-channel probing system with a time resolution of about 1 ms. This information can be used to control the plunger movements. The gap development which is important for the understanding of the thermal contact between the mold and the part due to the shrinkage is also monitored. Gap formation time periods versus different packing pressure and at different part locations with different part …  Read more

Cette étude applique test de impulsion transitoire pour mesurer les caractéristiques de faible perméabilité de cubes intactes de Cobourg calcaire. La méthode proposée utilise un système de pressurisation spécialement conçu pour générer des impulsions hydrauliques dans la cavité scellée. La pression de la cavité est alors autorisé à se dissiper que le fluide migre dans la matrice rocheuse saturée. Cruciale pour interpréter la perméabilité transitoire de ce test de perméabilité à la surface est l'influence des bulles d'air piégées à l'intérieur de la cavité sous pression. Les résultats de la modélisation indiquent que les inclusions d'air peuvent augmenter de manière …  Read more

The explosive growth in the information technology industry requires high-performance optical sources. In recent years, wavelength-tunable optical pulse sources are of interest for applications in optical instrumentation, communications, and sensing. This thesis demonstrates and analyzes the generation of wavelength tunable, picosecond pulses from mode-locked semiconductor fiber ring lasers. One structure using an intracavity electro-optic modulator and the other an injected optical control signal, are investigated and experimentally characterized. A single or superimposed linearly chirped fiber Bragg gratings are used to provide wavelength selectivity, tunability, and multi-wavelength operation. The semiconductor optical amplifier as the gain media makes it possible to obtain …  Read more

Les flux de travail en science des données se composent généralement d’une combinaison d'opérations relationnelles et de calculs numériques. Étant donné que les systèmes de gestion de bases de données relationnelles (SGBDR) traditionnels ne considèrent pas correctement les opérations d'algèbre linéaire, les experts ont recours à des solutions analytiques externes aux bases de données. Bien que certaines bibliothèques statistiques de langage de haut niveau (HLL) soutiennent des opérations relationnelles, leurs fonctionnalités ne sont pas comparables à celles du moteur de base de données. Comme de nombreux SGBDR ont intégré des interpréteurs HLL dans leurs implémentations, il est désormais possible d'avoir …  Read more

The effect of a low-Cu diet supplied to gilts during pregnancy and early lactation on dams and their offspring was obtained in seven pairs of first littermate gilts. They were housed in stainless steel metabolism cages in a controlled environment and fed semi-purified diets containing either 2.13 or 12.25 ppm Cu from 30 days of gestation through two weeks of lactation. Feed intake was restricted to 2 kg/day during pregnancy and 4 kg/day in the first two weeks of lactation. Reproductive performance of gilts was measured. Balance studies were conducted at 30, 60 and 100 days of gestation. Mineral levels …  Read more

The regulation of autoinduction of the luminescence (lux) system of the marine bacterium, Vibrio harveyi, has been studied. The autoinducer, which controls expression of the V. harveyi lux operon containing genes coding for luciferase and the fatty acid reductase complex responsible for synthesis of the aldehyde substrate, has been purified and structurally identified as N-$( beta$-hydroxybutyryl)homoserine lactone (HBHL). The $ beta$-hydroxybutyryl moiety of the autoinducer has been determined to be in the D configuration. The biosynthesis of the autoinducer was inhibited by exogenous fatty acids and/or cerulenin. These results suggest that the D-$ beta$-hydroxybutyryl moiety is directly derived from the …  Read more

Many statistical models involve three distinct groups of variables: local or nuisance parameters, global or structural parameters, and complexity parameters. In this thesis, we introduce the generalized profiling method to estimate these statistical models, which treats one group of parameters as an explicit or implicit function of other parameters. The dimensionality of the parameter space is reduced, and the optimization surface becomes smoother. The Newton-Raphson algorithm is applied to estimate these three distinct groups of parameters in three levels of optimization, with the gradients and Hessian matrices written out analytically by the Implicit Function Theorem it' necessary and allowing for …  Read more

The statistical analysis of brain functional and structural change presents a formidable statistical problem. Computation of a test statistic indicating change at each location of the brain gives a 3-D statistical image. The global maximum of the statistical image has been proposed by Friston et al. (1991) and Worsley et al. (1992) to test for regions of high change based on the belief that the changes are localized, not distributed. To find the correct p value, Worsley et al. (1992) modelled the statistical image as a stationary random field under the null hypothesis. The approximate p value of the global …  Read more

An overhead power transmission conductor must maintain a safe distance from the objects underneath it. However, this distance decreases with time, even under conditions where metallurgical creep of the cable material does not occur, for instance, at room temperature. This phenomenon is first identified as "pseudo creep". The creep behavior of a cable is directly related to its mechanical properties, which correspond to the applied loads under certain boundary conditions. Twist due to cable rotation and radial compression due to layer-to-layer contact are taken into consideration, so that a deeper understanding of what happens inside the cable and a quantitative …  Read more

The topic of teacher reflection has been gaining greater attention in the education literature. Nevertheless, teachers' reflective processes have not been well understood. This study attempted to describe characteristics and content of professors' post-class reflection. More specifically, it attempted to determine whether professors engage in the reflection process consciously and ways in which this process can be characterized. Eight professors, representing two levels of teaching experience, teaching a lecture or seminar undergraduate class in humanities or engineering, participated in this case study. Interviews, classroom observations, and instructional plans and materials comprised the data sources. Transcripts of the interviews were analyzed …  Read more

Les progrès remarquables dans la génération de langage naturel (GLN) ont transformé le domaine de la génération de langage naturel, mettant en avant des capacités sans précédent dans des domaines tels que la résumé, la traduction et la génération de contenu. Cependant, malgré ces avancées, un défi persistant demeure : assurer la factualité du texte généré—son alignement avec les matériaux sources ou les connaissances réelles. En particulier, les modèles entraînés sur d'immenses ensembles de données internet ont tendance à "halluciner" des informations, produisant du contenu qui, bien que plausible, n'est pas soutenu par la source donnée ou les faits établis. …  Read more

Henry, Chriscinda Claire (Internal/Cosupervisor2)  Read more

Laurent Azoulay (Supervisor2)  Read more

Isac, Mihaiela (Internal/Cosupervisor2)  Read more

Cette thèse examine l'éducation morale avec une étude comparative entre le programme d’Éthique et cultures religieuses (ERC) du Québec et le programme de l’'éducation morale de la Chine. Le but de cette étude est d'identifier les similitudes et les contrastes entre les deux programmes. En outre, il vise également à appliquer des théories dans l'étude de l'éducation morale pour explorer les facteurs derrière ces similitudes et différences. Dans la mesure où les recherches substantielles en éducation morale exposent un écart évident entre les théories et les pratiques, cette thèse vise à combler cette lacune.La méthodologie de cette thèse est la …  Read more

The effects of Ni, Pd and Pd77Ag23 alloy membrane microstructures on hydrogen permeation have been investigated using the electrochemical permeation method. Deformation, annealing and electrodeposition have been used to modify the membrane microstructure. The delay for hydrogen permeation in palladium is increased when the degree of deformation increases. The annealing of deformed palladium and Pd 77Ag23 at 250ºC or 850ºC accelerates hydrogen diffusion. The annealed metals release hydrogen more rapidly than the deformed metals. The Pd77Ag23 alloy needs more time to release hydrogen. The solubility increases in both palladium and Pd77Ag23 when deformation increases. A hydrogen-trapping model has been developed, …  Read more

Focal adhesion kinase (FAK), a non-receptor kinase, is a key regulator of integrin and focal adhesion signaling required for cancer cell survival, cell migration, and cell invasion. Amplification/Overexpression of FAK occurs in a wide variety of human cancers, supporting a role in carcinogenesis. Moreover, preclinical studies using cancer models where FAK is genetically inhibited indicate that this kinase is a potential therapeutic target to interfere with cancer progression. However, very little progress has been made in the identification of chemical inhibitors for potential therapeutic applications, in contrast to other kinases. Herein, I report optimization of the high-throughput in vitro Glo …  Read more

Reisner, Walter (Internal/Cosupervisor2)  Read more

Des interactions expertes avec des objets sonores, tel que le jeu des instruments à percussion, dépendent de la résolution d'incertitudes concernant la rétroaction provenant de signaux acoustiques et tactiles rayonnés par les objets mis en vibration. Cette incertitude pourrait découler d'une mauvaise estimation des propriétés mécaniques de l'objet, telle que sa rigidité. La façon dont le traitement intégré des informations auditives et haptiques générées par l'objet agit sur l'ajustement des actions qui produisent du son reste inexplorée. Les participants tenaient un stylet et ont appris à stabiliser la vitesse du poignée en frappant de façon répétée sur un objet sonore …  Read more

Radiation-induced salivary gland disfunction is a serious side effect of radiotherapy for head and neck cancer. The radiation damage of salivary gland tissue can lead to xerostomia with oral inflammation, rampant caries and trouble swallowing etc., which would severely compromise the life quality of patients. Hence, post-radiation salivary gland repair has been an important subject in dental medicine. Previous publication by our laboratory have shown that Bone Marrow Cell Extract (BMCE) has the capacity of restoring salivary gland function (Tran et al., 2013; Fang et al., 2015; Su et al., 2018). However, the effect of this treatment as well as …  Read more

Folates are essential vitamins involved in nucleotide synthesis and DNA methylation. Methylenetetrahydrofolate reductase (MTHFR) synthesizes the folate derivative utilized in methylation reactions. Inadequate dietary folate intake and MTHFR deficiency may increase the risk of developing colorectal cancer. Previous studies in our laboratory showed that a low folate diet induces intestinal tumors in BALB/c but not in C57Bl/6 mice. In addition, mild MTHFR deficiency (Mthfr+/-) may increase tumor formation in BALB/c mice fed low folate. To identify genetic differences responsible for tumor susceptibility, we performed microarray analysis to compare gene expression in preneoplastic intestine between BALB/c and C57Bl/6 mice fed low …  Read more

Hypertension and its associated cardiovascular risks can be attributed to angiotensin II (AngII), which regulates blood volume and vascular resistance through the AngII type 1 receptor (AT1R). As a G protein-coupled receptor (GPCR), the AT1R signals by coupling to G proteins (Gαq/11, Gα12/13, Gαi1/2/3) and β-arrestins (β-arr1 and 2, which act both as endocytic and signaling adaptors) to mediate its physiological effects. While most drugs that target the AT1R act by blocking the activation of the receptor and thereby attenuating all of its downstream signaling pathways indiscriminately, studies have highlighted that certain AT1R-mediated pathways may promote beneficial cardio-protective effects. Thus, …  Read more

Jakobson, Dmitry (Supervisor1)  Read more

Plusieurs approches au niveau logiciel pour la spéculation des fils d'exécution (TLS) ont récemment étées explorées, évitant la nécessité de concevoir du matériel informatique spécialisé. Cependant, ces approches ont tendence à se concentrer sur des implémentations au niveau du code source or des machines virtuelles qui sont destinées à des langages ou environnements particuliers. De plus, les approches logicielles précédentes ont eu tendance à utiliser un modèle de fork de fils d'éxécution plutôt simple, réduisant leur capacité à extraire du parallélisme important à partir de programmes récursifs de forme arbre. Nous proposons un système "Mixed forking model Universal software-TLS (MUTLS)" …  Read more

Background. beta-blockers have been the cornerstone of therapy for hypertension for at least 20 years. The use of newer agents including calcium antagonists and ACE inhibitors is increasing. Objective. To examine whether calcium antagonists and ACE inhibitors independently are associated with increased all-cause and cause-specific mortality relative to beta-blockers. Methods. This was a population-based cohort study. Within the cohort, a nested case-control approach was used for analysis. We used Saskatchewan Health databases. A cohort of 19,501 subjects initiating therapy for uncomplicated hypertension between January 1st, 1990 and December 31st, 1993 was identified. Cases were all deaths between January 1st, 1990 …  Read more

Robertson, Dr. A. A.  Read more

Egalitarianism is highly valued in Canada and yet some groups are profoundly disadvantaged. This can be explained by sociological and psychological theorizing that claims advantaged group members are motivated to maintain a system of inequality from which they benefit. The challenge is to explain the few advantaged group members who defy self-interest and support disadvantaged groups. My research objectives were to understand what motivates selected advantaged group members to support disadvantaged groups, and to understand how the majority of advantaged group members maintain their belief in egalitarianism in the face of clear social inequality. Results revealed that most advantaged group …  Read more

En général, les psychologues conçoivent le sentiment de la culpabilité comme un processus intrapsychique où les gens ressentent de la détresse lorsqu'ils sont confrontés à leurs transgressions. Cette détresse motive souvent les gens à utiliser des défenses psychologiques pour apaiser leur sentiment de culpabilité. Par conséquent, lorsque les gens affirment ne pas se sentir coupable, il est difficile de distinguer les gens qui ne se sentent véritablement pas condamnables de ceux qui se protègent contre la détresse rattachée à un sentiment de culpabilité. De façon comparable aux travaux classiques qui ont démontré que les gens ont tendance à éviter la …  Read more

Childress, Lilian (Supervisor1)  Read more

A pneumatically-actuated membrane device is designed and fabricated to dynamically confine multiple DNA chains into nanoscale pit features. A nanoscale nitride membrane is used as a lid that deflects under pneumatic pressure. With this device single λ-DNA and plasmid DNA are studied in a confined environment. In addition systems are studied containing two λ-DNA chains or a single λ-DNA with a plasmid. The interactions of multiple confined macromolecules were quantified, which is relevant in the study of biological systems in which multiple DNA molecules are highly confined by cell walls and other organelles. This confinement is found to greatly impact …  Read more

Serving as the extra-thalamic relay from the ascending reticular activating system to the cerebral cortex, basal forebrain neurons and particularly the cholinergic neurons therein, are believed to play an important role in cortical activation that occurs during waking and paradoxical sleep (PS). However, basal forebrain neurons are also thought to be involved in slow wave sleep (SWS), and thus accordingly influence cortical activity in different ways across the sleep-waking cycle. The present research aimed to elucidate the way the basal forebrain modulates cortical activity and sleep-wake states in response to the different neurotransmitters contained in its brainstem afferents. Microinjections of …  Read more

It is now generally accepted that the sequence of nucleotide moieties in DNA is the stable genetic message in ail organisms except RNA viruses. Nucleotide sequence in DNA is believed to function as a blueprint or template; various kinds of RNA molecules are "transcribed" from DNA and their nucleotide sequence is determined by that of the DNA template. These RNA molecules participate intimately in the execution and control of protein synthesis and their nucleotide sequence is of primary importance in fulfilling this role. [...]  Read more