McGill University Thèses et mémoires par auteur commençant par S

Sabok, Marcin (Internal/Supervisor)  Lire la suite

This thesis deals with the appraisal of the economics of underground conversion in surface limestone mining operations. Software that predicts the time at which an open pit operation should be converted to underground extraction has been developed. The software is based on estimates of capital expenditures required for the underground conversion and for future equipment acquisitions and replacements under both open pit and underground operating alternatives, as well as long-term operating cost estimates for both alternatives. Open pit and underground cost estimates can be entered either directly, or estimated using O'Hara and Suboleski's (1992) cost estimation equations. It is assumed …  Lire la suite

When subjects are recruited through a cross-sectional survey they have already experienced the initiation of the event of interest, say the onset of a disease. This method of recruitment results in the fact that subjects with longer duration of the disease have a higher chance of being selected. It follows that censoring in such a case is not non-informative. The application of standard techniques for right-censored data thus introduces a bias to the analysis; this is referred to as length-bias. This paper examines the case where the subjects are assumed to enter the study at a uniform rate, allowing for …  Lire la suite

Cancer is a disease recognized in antiquity. Its name, “Kapkivos”, a crab, was derived from the ancient description of breast cancer. Until the Nineteenth Century, it was entirely within the therapeutic province of the physician and surgeon. According to Bett (1957), Bernard Peyrilhe (1735-1804) was the first to conduct a systemic experimental investigation of the causation of cancer, in which he attempted to identify its toxin, and to trace the spread of the disease in order to devise better methods of treatment. Although more than two hundred years have passed since Peyrilhe's attempt, research into the cause of cancer is …  Lire la suite

The earliest description of cancer has been traced back to records on Egyptian papyri of the fifteenth century B.C. Following this, in the era of Hippocrates, in the fourth century B. C., the nature of cancer was described as the presence of a tumour, and the absence of any tendency towards healing. Hippocrates used the term “kapkivos” , "carcinos”, for all indolent ulcers, and “kapkivwua”, "carcinoma” for progressive malignant tumours. In spite of many descriptions, and many personal views as to the origin of cancer in the following centuries, little came but mere speculation. Perhaps, the one of the most …  Lire la suite

The research work to be described in the following pages of this thesis deals with a further investigation of the properties of cellulose and especially the cellulose -water system. While the organic structure of cellulose is important, this physico-chemical investigation deals with the physical structure of cellulose and the influence of water upon it. When it is considered how much of the nature of cellulose is bound up in its fibrous structure, its tensile strength, and the swelling behavior that it exhibits, it is seen how inadequate are formulae which explain only its chemical reactions and leave its physical properties …  Lire la suite

Pedersen, E. (Supervisor)  Lire la suite

At the present time in Canada, all but a small proportion of the milk for fluid use is transported from farm to dairy by truck. Usually this operation is carried out by an enterpriser whose sole business is the hauling of milk from the primary producer to the distributor. On the average, the cost of transporting milk from the farm to the distributor amounts to about three-quarters of a cent-/per quart. Whether this amount represents the cost of bringing an adequate supply of high quality milk to the market, avoiding inefficiency and/or excessive profits, is a question which concerns the …  Lire la suite

The manipulation of nature using modern biotechnology has resulted in the creation of Genetically Modified (GM) foods. There are states already enacting laws requiring the mandatory labeling of GM foods so that consumers can make informed choices as to what food to eat. However, on the flip side, the mandatory labeling of GM foods can also constitute non-tariff barriers as it can impose burdens on states that export GM foods. How should these two interests be balanced? This thesis takes the ambitious challenge of exploring whether the mandatory labeling of GM foods enacted under the government's protection of the consumers' …  Lire la suite

A series of small mud mounds are exposed in the McConnell and Miette thrust sheets on the southern flank of the Miette reef complex. They occur on the southeastward inclined carbonate clinoforms of the late Frasnian Arcs Member. These mounds are rooted on marine, argillaceous lime mudstones and are surrounded by lime mudstones of several prograding clinoforms of the upper Arcs Member or dolomitic siltstones of the lower Ronde Member. Mounds are approximately 17 to 36 m high and 32 to 81 m wide and columnar to domal in shape. The lower part of the mounds consists of sponge-rich wackestones …  Lire la suite

La demande croissante de densité de bande passante et de protocole IP (Internet Protocol) provoque un goulot d’étranglement dans les systèmes de communication. La technologie du silicium sur isolant (SOI) permet une faible perte d’absorption, un contraste d’indice élevé entre le noyau et l’oxyde environnant, ainsi qu’une transmission de données de bande passante élevée qui améliore la performance énergétique par bit des interconnexions du centre de données. La densité de bande passante peut être augmentée davantage en employant des techniques de multiplexage telles que le multiplexage par division de polarisation (PDM), le multiplexage par répartition en longueur d’onde (WDM) et …  Lire la suite

Cette thèse, inspirée par l'application de dispositifs de réduction électrochimique du dioxyde de carbone et la recherche de catalyseurs et d'électrolytes idéaux pour ces systèmes, est divisée en deux sections principales. Chaque section se concentre sur un aspect crucial du dispositif de réduction électrochimique polyvalent du dioxyde de carbone : le catalyseur solide, en mettant l'accent sur les alliages monoatomiques (AMA), et l'électrolyte, composant clé des instruments de réduction du dioxyde de carboneNotre exploration commence par une évaluation détaillée de l'efficacité des descripteurs basés sur les bandes d, ancrée dans la théorie de la réactivité des bandes d, pour prédire …  Lire la suite

Kubes, G. J. (Supervisor)  Lire la suite

The classical theory of poroelasticity developed by Biot (1941) deals with the time-dependent response of the fluid-saturated porous media derived from the coupling of the mechanical deformations and the deformations of pore fluid. The classical theory of poroelasticity has been successfully applied to a range of problems of interest to geomechanics and biomechanics. The brittle poroelastic media can experience alterations in poroelasticity properties resulting from the generation and/or growth of micro-defects. The effects can be modelled by appeal to continuum damage mechanics. Damage-induced alterations can influence the consolidation behaviour of a damage-susceptible poroelastic medium. Continuum damage mechanics concepts can be …  Lire la suite

Esmail, Nabil (Supervisor)  Lire la suite

The need for the development of a rigorous analytical model of the lumbar spine to clarify the role of mechanical factors in low-back disorders has long been recognized. In response to this need, a general three dimensional nonlinear finite element program has been developed as part of this work and has been applied to the analysis of a lumbar L(,2-3) joint including the posterior elements. The analysis accounts for both the material and geometric nonlinearities and is based on a representation of the nucleus as an incompressible inviscid fluid and of the annulus as a composite of collagenous fibres embedded …  Lire la suite

Dans le cerveau adulte, l’acide gamma-aminobutyrique (GABA) agit comme le principal neurotransmetteur inhibiteur, cependant, dans le cerveau en développement, le GABA a des actions excitatrices. Les effets résultant de l'activation des récepteurs GABAA peuvent être une hyperpolarisation ou une dépolarisation, selon le chlorure intracellulaire [Cl-] qui est régulé par l'activité des cotransporteurs de cations-Cl-- (CCC) tels que NKCC1 et KCC2. Dans les neurones, NKCC1 et KCC2, en accumulant et en extrudant respectivement du Cl-, régulent les fonctions des récepteurs GABA en maintenant l'homéostasie intracellulaire du Cl-. Cependant, l'échec de la fonction des récepteurs GABAA a souvent été considéré comme un …  Lire la suite

Emotional eating, or overeating in response to negative emotions, is problematic because of its association with an increased risk for overweight and obesity, difficulties losing weight, diabetes, and heart disease. As such, several studies have focused on understanding the mechanisms that underlie this behavior and ways of reducing it. This dissertation consists of three studies that investigate how mindfulness influences the self in reducing emotional eating. The first study systematically reviews the study of the self within the mindfulness literature and sets the stage for the investigation of the self and mindfulness in emotional eating. The results of this review …  Lire la suite

Epilepsy is a neurological disorder characterized by excessive neuronal activity in the brain that manifests as spontaneous seizures. Mesial temporal lobe epilepsy (MTLE) is the most common form of focal epilepsy involving seizures that originate from the hippocampus and parahippocampal structures. Seizures occurring in MTLE patients and in experimental models mimicking this neurological disorder can be classified based on their onset pattern, into low-voltage, fast (LVF) and hypersynchronous (HYP) onset seizures. Experimental evidence suggests that LVF-onset seizures mainly result from the synchronous activity of GABA releasing cells while HYP-onset seizures tend to rely on glutamatergic signaling as well. However, despite …  Lire la suite

Aging is the system wide loss of cellular functions eventually leading to the death of an organism. Just as the microbiome actively evolves with its aging host, it also tends to directly influence aging via modulation of metabolites which affect important cellular functions. The widely used model organism C. elegans exhibits high selectivity towards its microbiome members which belong to different classes of bacteria and exhibit a wide range of contrasting properties in their colonization capacity, their effects on the healthspan and the rate of development of the worm. A recently studied native microbiome member belonging to the phylum Bacteroidetes, …  Lire la suite

This thesis is about the design and implementation of a program transformation technique for parallelizing loops. The technique is based upon unimodular transformations that was originally proposed to parallelize imperative language loops. Such loops, in which arrays are the dominant data structure, often contain ample parallelism. Baherjee in (Ban90) proposed algorithms to parallelize double loops in imperative languages. His technique subsumes other results in the area of parallelizing double loops. We have implemented those algorithms in a program called U-Transformer. In recursively defined Monolithic Array Constructors in functional languages, which we refer to as MACs, a major problem that arises …  Lire la suite

Le glioblastome multiforme (GBM) est un stade avancé de cancer du cerveau avec un très faible taux de survie. Sa récurrence est assez fréquente, causée par la présence de cellules tumorales en dehors de la masse primaire, ce qui rend difficile la résection chirurgicale. Des recherches antérieures dans notre laboratoire ont suggéré un lien entre le pouvoir envahissant du GBM et CRMP1 (Collapsin Response Mediator Protein 1), un membre d'une famille de phosphoprotéines impliquées dans la dynamique du cytosquelette et déjà considéré comme un gène suppresseur d’invasion dans le cancer du poumon. Le but de cette étude était d'examiner le …  Lire la suite

L'utilisation des matériaux a connu une croissance exponentielle au cours des dernières décennies ; la motivation pour développer de nouveaux matériaux capables de combiner plusieurs propriétés souhaitées dans un seul matériau et en utilisant une quantité limitée de matériau a conduit à des matériaux multifonctionnels architecturés. Parallèlement, les ingénieurs se sont inspirés des solides cellulaires naturels, tels que le bois et l'éponge, qui présentent une combinaison de légèreté, de rigidité spécifique élevée et de propriétés thermomécaniques accordables. En conséquence, une nouvelle catégorie de matériaux architecturés a été introduite sous le nom de métamatériaux cellulaires, qui permet d'atteindre des propriétés dépliées, …  Lire la suite

Bone marrow toxicity imposes severe limitations on current cancer therapy. To test the feasibility of overcoming chemotherapy-induced hematopoietic suppression, the chemoresistance gene GST was transferred into hematopoietic progenitor cells using the bicistronic retrovirus vectors GIC and GID. As reported herein, GIC transduction of mouse hematopoietic cells resulted in increased in vitro resistance to mechlorethamine (up to 6-fold) and Ara-C (up to 9-fold). Likewise, transduction with GID bicistronic vector conferred increased resistance to mechlorethamine (up to 16-fold) and MTX (up to 12-fold). Furthermore, ex vivo pre-selection of GID-transduced cells was shown to double the fraction of TMTX-resistant progenitor cells. These results …  Lire la suite

When rat brain is homogenised in plain sucrose solution about 20-35% of tissue GABA, L-glutamic acid, L-aspartic acid, L-alanine, L-glutamine and glycine are found to be occluded by brain particles. An extra 30% for GABA and 10-15% for the other five amine acids are bound if the medium contains 40 mM NaCl. These sodium-dependent bound forms are in rapid equilibrium with the free amine acids in the medium. The binding characteristics of L-glutamine resemble that of GABA. Both ouabain and protoveratrine inhibit the binding (sodium dependent) of these amino acids to brain particles. Their effects are greatest on GABA. Exchange, …  Lire la suite

A cell membrane component(receptor) which binds prolactin and other lactogenic hormones with a high degree of specificity and affinity has been identified and studied in mammary glands obtained from pregnant and lactating rabbits. In rat mammary tumors induced by 7,12-dlmethylbenzanthracene a significant positive correlation was found between the binding of prolactin to membrane fractions isolated from the tumors and the growth response of the tumors to the administration of prolactin, suggesting that the prolactin receptor is one factor which determines the degree of hormonal dependency of these tumors. The particulate membrane receptor isolated from the rabbit mammary gland has been …  Lire la suite

Barthelat, Francois (Supervisor1)  Lire la suite

Microwave drying of corn was investigated at selected levels of initial moisture content, absorbed power by grain, and temperature and superficial velocity of air at inlet. A surface-wave applicator was used to couple microwaves with the corn. The drying rate curves indicated that the microwave drying of corn took place in the falling rate period. It was hypothesized that diffusion is the controlling mechanism for moisture transfer from within the kernel in microwave drying of corn. A mathematical model was developed to describe the change in moisture content at the surface as a function of the free moisture content of …  Lire la suite

Background and ObjectiveFetal growth and size are known indicators of perinatal health, although the etiology of this relationship is unclear, and twins are known to differ from singletons with respect to fetal growth trajectories over the course of pregnancy. With a lack of research on ultrasound-based fetal weight references in twin populations, this study aimed to construct ultrasound-based in utero fetal weight references for each gestational age for a twin population.MethodsTwins delivered at a tertiary care hospital in Montreal were used in this study. Fetal weight was calculated using a published formula that was validated in this population. Fetal growth …  Lire la suite

The electronic equation was checked for modulated beams, subjected to various potential distributions. A demountable system with two cavities was used. In a drift tube, the d.c. current or voltage or distance was varied. The maxima and minima points in the patterns were investigated for phase and power. The power at the second maximum was less than theory predicted. Results on a sealed off tube were similar. The discrepancy was probably due to secondary electrons.  Lire la suite

The field patterns in the aperture and in front of the mouth of conical horns, with small flare angles, under TEll excitation, are measured. In the aperture, electric and magnetic fields are determined, both in the E and H-planes, for effective apertures, varying in diameter from 5 to 8. Field patterns in the Fresnel region are taken for horns, having mouth diameters of 5 and 8. Measurements are given, as well, for a square horn, of aperture 8 to a side, under TEIO excitation. Deviations, from the field values in a horn of infinite length, occur in the electromagnetic field …  Lire la suite

This work proves the pathogenicity of four substitution mutations in the androgen-binding domain of the human androgen receptor (hAR) gene of four subjects with varying degrees of androgen insensitivity syndrome (AIS): complete (CAIS), partial (PAIS), or mild (MAIS). Of three unrelated CAIS subjects, two have Arg830Leu, the third has Arg830Gln. Their genital skin fibroblasts (GSF) have negligible androgen binding, but in overexpressing transfectants, the mutant androgen-binding activities have increased dissociation rates and decreased affinity for androgen. Owing to the instability of AR-androgen complexes, both mutants fail to transactivate a reporter gene. Glu771Ala and Arg870Gly caused PAIS and MAIS, respectively. Their …  Lire la suite

Les expansions répétées hexanucléotidiques du gène C9orf72 sont la principale cause du développement de deux maladies neurodégénératives: la sclérose latérale amyotrophique et la démence fronto-temporale. Des études antérieures ont montré que C9orf72 se lie à SMCR8 et WDR41 pour former un complexe stable. Ce complexe s’est révélé important lors de l’autophagie dans les cellules neuronales. Cependant, les fonctions exactes du complexe et ses caractéristiques structurelles sont principalement inconnues. Ici, nous avons établi un protocole de purification pour le complexe protéique C9orf72-SMCR8-WDR41. Nous avons construit un seul plasmide contenant les trois protéines pour une expression efficace dans les cellules d'insectes Sf9. …  Lire la suite

Dudek, Gregory L (Internal/Supervisor)  Lire la suite

Dans cette thèse, nous considérons les robots mobiles autonomes comme des plate-formes de collecte de données visuelles qui fonctionnent aux côtés d’experts hu-mains pour les aider enregistrer le type de métrage dont ils ont besoin. Ce pointde vue est utile dans des applications telles que la surveillance environnementalecollaborative homme-robot, où par exemple, un plongeur doit explorer un envi-ronnement marin assisté par un robot sous-marin; dans la recherche visuelle etl’inspection, où un agriculteur doit obtenir images de cultures à risque de maladie;ou dans la cinématographie robotique d’événements sportifs. Dans tous ces cas,les robots agissent en tant que vidéographes pour le compte …  Lire la suite

The spectacle of men who are able and willing to work in order to provide for themselves the necessities of life, and who are unable to find employment, is not an edifying one. When these unemployed number hundreds of thousands, and are spread throughout the world, they constitute a threat to society; but chronic unemployment of a seasonal nature which persists during good times and bad is just as formidable an indictment on industry. Everyone knows the paradox of cyclical unemployment. When granaries are overflowing and other commodities are plenteous there are people who are hungry and ill-clothed; when the …  Lire la suite

This thesis examines the administration of the Late Roman or Early Byzantine Empire under Maurice (582-602). His reign is not commonly known, and he is often given brief mention only together with the other rulers following the reign of Justinian the Great, although his era spans twenty eventful years. Indeed, his rule is of considerable importance since it is in his time that we first hear about new administrative structures such as the Exarchates of Carthage and Ravenna. The focal point of this thesis is the military and civil administration of the Empire at the end of the sixth century. …  Lire la suite

Acid mine drainage (AMD) is one of the largest problems facing the mining of base metals in Canada today. It results in the leaching of toxic heavy metals from waste rocks and tailings into the environment. Solidification/stabilization is a process whereby hazardous wastes are chemically stabilized and their handling properties improved. The objective of the project was to stabilize two tailings obtained from base metal mines in Quebec by adding varying proportions of lime and fly ash to them. The fixing capabilities of the two additives were tested by a modified Toxicity Characteristic Leaching Procedure (TCLP) test after 1, 14 …  Lire la suite

Ouellet, Jacques (Internal/Cosupervisor2)  Lire la suite

Greer, Charles W. (Supervisor)  Lire la suite