McGill University Thèses et mémoires par auteur commençant par P

The Amba Dongar carbonatite complex, India is host to a large fluorite deposit. The complex consists of a small ring structure comprised of early carbonatite breccia, a large, outer lining of calcitite and a number of small ankeritic carbonatite plugs. Surrounding the carbonatite ring are numerous plugs of nephelinitic and phonolitic syenites. The complex was intruded into Late Cretaceous Bagh Sandstones and Late to Early Paleocene Deccan Volcanics. The hydrothermal history of the complex is extensive, consisting of two main systems, the first resulted in large amounts of fenitization, causing extensive K and Na metasomatism of the surrounding sandstones and …  Lire la suite

The Amba Dongar complex, India, consists of calciocarbonatite, ankerite-dominated ferrocarbonatite and numerous nephelinitic bodies intruded into Late Cretaceous quartz sandstones and Deccan basalts. Ankeritic (mottled) and calcite +/- barite +/- ankerite (multiphase) melt inclusions were observed in apatite hosted by calciocarbonatite. Mottled inclusions start melting at temperatures of 610°C and are completely molten at temperatures >800°C. The onset of melting, of multiphase inclusions, is at 680°C, and final melting occurs above 1100°C. Based an the coexistence of mottled (ankeritic) and multiphase (calcitic) inclusions, a model is proposed for the genesis of calciocarbonatite and ferrocarbonatite that calls upon separation of immiscible …  Lire la suite

Freshwater ecosystems worldwide are being altered by multiple stressors. One of the most important stressors is biological invasion---the introduction of exotic species, which can contribute to the loss of native species. The effects of an introduced species are correlated with its abundance and typically vary across ecosystems, suggesting that its impact on native species is mediated by its environment, i.e. the physical habitat and the recipient community. However, there are few studies that explore the effects of environment on the interactions between exotic and native species. My thesis examines the influence of physical habitat variables and community interactions on the …  Lire la suite

McKenzie, Jeffrey (Internal/Supervisor)  Lire la suite

Ten centimeter radar echoes from rain and snow are discussed quantitatively from a theoretical and experimental point of view. Measurements of the power back-scattered by rain and snow are correlated with precipitation measurements made at the ground. The theory of ten centimeter radar echoes from rain has been checked by experiment. Radar echoes from continuous precipitation are analysed in height in a quantitative manner. The distribution of precipitation with height in non-convective meteorological situations is estimated from radar measurements.  Lire la suite

The distribution of raindrops and snow particles with size have been measured at the ground and a general relation has been evolved covering both cases. The vertical structure of continuous precipitation has been investigated by means of ten centimetre radar and a special study of the height and thickness of the bright band at the freezing level has been made using an anti-aircraft radar. These radar measurements indicate that the snow particles aggregate and form large snowflakes in the vicinity of the freezing level. The snowflakes probably fall a distance of about 500 to 1,000 feet below the freezing level …  Lire la suite

The theory of Ronis and Vertenstein [J. Chem. Phys. vol. 85, 1628, (1986)] is used to calculate the permeability of Xenon in Theta-1 and of Argon in alpha-quartz, both crystalline sodalites containing large, one-dimensional channels in the first case and narrow interconnected channels in the second. The simulated dynamics of a small part of the crystal atoms exactly reproduce those of the full crystal by the means of a generalized Langevin classical equation of motion. An approximate expression for the potential of mean force inside the crystal is derived. The Theta-1 energy landscape is smooth with small energy barriers while …  Lire la suite

Park, Morag (Internal/Cosupervisor2)  Lire la suite

Gillett, Margaret (Supervisor)  Lire la suite

Hudson, Thomas (Supervisor2)  Lire la suite

Macchi, Maria (Internal/Cosupervisor2)  Lire la suite

Walsh, Catherine (Supervisor)  Lire la suite

The earliest historical records tell us that the artificial production of temperatures below that of the surroundings was already used by the Egyptians of 2500 B.C. who knew that water could be cooled in porous jars by fanning them. A similar old Indian custom for ice making involved the rapid evaporation of water into a very dry atmosphere. Other methods, such as the use of freezing mixtures, have been known for centuries.  Lire la suite

Palmer, W. (Supervisor)  Lire la suite

The finding that more than 152 tissue-restricted antigens are expressed by thymic medullary epithelial cells is redefining the importance of thymic central tolerance induction in the prevention of autoimmune diseases. One of the tissue-restricted antigens in the thymus is proinsulin, and in both mice and humans, reduced thymic proinsulin levels have been shown to predispose to Type 1 diabetes. Using transgenic mice expressing a functional beta-Galactosidase gene under the regulation of the Ins2 promoter we have determined that between 1-3% of all medullary thymic epithelial cells express proinsulin and that these cells are frequently part of the Hassall's Corpuscles like …  Lire la suite

In the last few decades, there has been an increasing worldwide problem of deterioration of reinforced concrete structures, caused primarily by the corrosion of the steel reinforcement embedded within the concrete. Several factors can influence the corrosion process in different types of inservice structures. This thesis reviews the basic principles of the reinforcement corrosion. Various protection and rehabilitation schemes that can be undertaken in the repair of deteriorated concrete structures are presented. In particular, three specific types of structures in the Montreal region which have undergone rehabilitation are presented as typical case studies. Additionally, major research work done in the …  Lire la suite

This study explores how to integrate faculty-initiated Internet-facilitated international academic partnerships into their local university environments. Recently some faculty have begun initiating international partnership activities which carryout their university's research, teaching, and service missions. These partnerships (including courses, projects, or entire programs) are considered by their initiators to benefit both faculty and student development. Faculty see the Internet as enabling them to construct interactive and collaborative virtual forums where disperse student and faculty bodies can co-engage in exciting international research, teaching, and learning opportunities. This study aims to encourage the development of Internet-facilitated international academic partnerships so that more faculty …  Lire la suite

Aerodynamic heating of a swept wedge airfoil was investigated in a Mach Number 2.58 flow for various sweep angles. The 2 in. x 1 1/4 in. surface size airfoil was made of stainless steel with a sharp leading edge and a wedge angle of 22.0 degrees. The angle of attack in a plane normal to the leading edge was constant at 5 degrees, the sweep angle varied from 0 to 35 degrees in five degree increments. Forty chromel-alumel thermocouples were welded to one surface of the wedge, in order to measure the temperature distribution of the surface.  Lire la suite

Voigt, Kristin (Supervisor2)  Lire la suite

Schwartzman, Kevin (Internal/Supervisor)  Lire la suite

Des antigènes spécifiques de la surface membranaire de réticulocytes de mouton ont été isoles en utilisant des anticorps spécifiquement développés contre la surface cellulaire. Le récepteur de la transferrine a été identifié comme l'antigène spécifique majeur des membranes. La caractérisation du récepteur a permis de déterminer un poids moléculaire d'environ 93,000 pour sa forme monomérique et qu'il existe probablement in situ sous une forme dimérique. Il a été aussi établi que les sites antigéniques diffèrent de ceux impliques pour la liaison avec la transferrine. De plus, mous avons montré que la quantité de récepteurs de la transferrine décroit pour éventuellement …  Lire la suite

In the N2 fixing legume symbiosis, mineral nitrogen (N) not only decreases N2 fixation, but also delays and inhibits the formation and development of nodules. The purposes of this thesis were to elucidate the role of signaling in the mineral N effects on nodulation and nitrogen fixation in soybean [Glycine max (L.) Merr.] and to attempt to find ways to overcome this inhibition. The responses of soybean plants, in terms of daidzein and genistein synthesis and exudation, to different mineral N levels were studied. Daidzein and genistein distribution patterns varied with plant organs, mineral N levels, and plant development stages. …  Lire la suite

Le récepteur du facteur de croissance épidermique (EGFR), un conducteur oncogène éminent, a été un objet majeur dans l'avènement de la médecine personnalisée et a obtenu un succès considérable sous la forme d’anticorps et d’inhibiteurs de kinase de tyrosine d'EGFR (EKI). Les vésicules extracellulaires (VE) sont des fragments de membrane qui jouent un rôle important dans la communication cellulaire à courte et longue distance en transportant un chargement biologiquement actif, y compris des protéines, des lipides et des acides nucléiques. Les VE jouent un rôle crucial dans la transformation cellulaire, l'angiogenèse et la métastase. Cette thèse explore la relation entre …  Lire la suite

La topologie d’un réseau est un facteur important dans la performance de tout système de calcul distribué, comme les centres de traitement de données ou les superordinateurs. Parce que les superordinateurs doivent être reprogrammables et doivent accomplir des tâches variées, leurs topologies sont également à usage général, sans favoriser aucune tâche. Cependant, certaines applications pourraient grandement bénéficier d’une topologie de réseau plus spécialisée. Une solution serait d’avoir un réseau dynamique qui pourrait être reconfiguré avec des topologies spécialisées pour chaque tâche. Cela pourrait être accompli en introduisant des commutateurs de point de croisement, tels que le Pont Optique Hybride de …  Lire la suite

The history of applied superconductor-based equipment in industry, especially in power system, is briefly reviewed. The thesis presents a development of a superconducting magnetic energy storage system for power quality improvement and uninterruptible power supply (PQ/UPS SMES). The configuration of such a system and its control concept are analyzed in full details. Evaluation tests of an SMES system operating on a simple power system are presented and analyzed. They validate the applicability of such a system, as an attractive alternative for power quality improvement and uninterruptable power supply. The PQ/UPS SMES system as well as the power network has been …  Lire la suite

The Archean rocks in the D'Alembert-Clericy area of the Noranda district were mapped along a transect across stratigraphy. Located within the youngest part of the Blake River Group, this six km thick volcanic assemblage trends northwest, youngs northeast, and has increasing dip from $ sim$45$ sp circ$ in the west to subvertical in the east, with some folding within the sequence. Chemostratigraphic units were established using Zr/Y, La$ sb{ rm N}$/Yb$ sb{ rm N}$, and other immobile and incompatible HFSE ratios, and AFM and Miyashiro major element plots. Lithogeochemical technique based on the HFSE and other immobile and incompatible elements …  Lire la suite

Calcium imaging is an invasive brain imaging method that detects the influx of calcium ions during neural activities such as action potentials, NMDA spikes, etc. It’s a popular technique with advantages such as high spatial resolution, preserving spatial compositions, etc. However, due to the noisy and sparse nature of the fluorescent signals, a lengthy and complex preprocessing pipeline is usually required before calcium imaging data can be used for downstream purposes. In recent years, there have been many machine learning and deep learning models working to obtain high-quality reconstructions of neural signals and downstream decoding, such as decoding animal behaviours. …  Lire la suite

To optimize irrigation water use, temporal and spatial sensor-based data related to soil water content were integrated. Nine locations in a 37-ha agricultural field were selected using field elevation and soil ECa maps for monitoring the soil matric potential and temperature at four depths (18, 48, 79 and 109 cm) with a wireless sensor network. Using a linear regression approach, a series of time-specific equations were developed to quantify both the temporal and spatial soil water stress status through a Water Stress Index (WSI). The WSI was estimated using soil matric potential measurements along with supplemental soil characteristics, such as …  Lire la suite

Compte tenu de l'hypothèse largement répandue que la majorité des chinois moniteurs de l'école de langue du patrimoine utiliser un modèle du pays d'origine, j'étudie six professeurs de langues du patrimoine montréalais dans un effort pour identifier les particularités de leurs pratiques d'enseignement. Mon enquête utilise des méthodes de recherche qualitative, y compris les entretiens et d'observations. Les résultats montrent que les enseignants qui ont participé à cette étude sont prêts à changer leurs pratiques d'enseignement en fonction de leur nouvel environnement. Toutefois, leur efficacité en faisant diffère. Les résultats suggèrent que l'expérience d'enseignement avant professeurs de langues de patrimoine …  Lire la suite

Zhao, Yaoyao Fiona (Supervisor1)  Lire la suite

Bien que l'agriculture consomme 80 à 90% de la production annuelle et mondiale de phosphore (P), les plantes n'en utilisent efficacement que 20%, le reste étant rejeté dans l'environnement aquatique ou s'accumulant dans le sol. Le modèle RZWQM2-P a été nouvellement développé et ensuite intégré dans le modèle RZWQM2, fonctionnant comme un seul outil pour la description des activités du P dans les champs agricoles. Les Objectifs de cette étude étaient : (1) d'évaluer l'exactitude et la rationalité du modèle RZWQM2-P ainsi que d'améliorer sa logique et son algorithme en appliquant le modèle RZWQM2-P qui vient d'être développé ; (2) …  Lire la suite

In the study of nuclear structure, several physical models of nuclear behavior have been developed. The shell model, based on independent particle motion in an average nuclear field, is successful in explaining many aspects of nuclear phenomena, such as regularities in parities, and nuclear ground state spins, and the unusual stability of closed shell nuclei. [...]  Lire la suite

The T cell receptor (TCR)/CD3 complex consists of a TCRalphabeta heterodimer and invariant CD3gamma, delta, epsilon and zeta chains. CD3 components play a critical role in T-cell development and function. Thymocyte development is impaired at the CD4-CD8- double negative stage in CD3gamma-, epsilon-, or zeta-deficient mice, whereas CD3delta deficiency impairs thymocyte maturation at the CD4+CD8 +double positive stage. However, the stoichiometry of CD3gamma and CD3delta chains on the surface TCR/CD3 complex has not been determined. In the present study, transgenic mice expressing a truncated form of CD3delta and CD3gamma that lacked the whole cytoplasmic domain were employed to show that …  Lire la suite

Barras, Laurent (Supervisor1)  Lire la suite

Electrocatalysis, which facilitates the interconversion between electric and chemical energy, has been considered as an efficient and green route to produce clean energy and chemical feedstocks. Nevertheless, conventional chemical protocols for synthesizing nanosized metallic electrode materials frequently involve the use of non-natural stabilizing additives, hazardous solvents and high temperature, which requires high energy input and raise some environmental concerns. Searching for green catalysts with excellent catalytic performances are highly desired. In this regard, bioinspired syntheses are emerging as greener and more energy-efficient alternatives, since they enable fabrication of well-patterned hierarchical micro and nanostructures under mild reaction conditions. Among the different …  Lire la suite

Ciampi, Antonio (Supervisor)  Lire la suite

Somatostatin exerts a primarily inhibitory effect across multiple physiological systems, including endocrine and exocrine secretions, through a family of 5 G-protein coupled receptors named somatostatin receptor 1 through 5 (sst1-sst5). In AtT-20 cells which primarily co-express sst2 and sst5, sst2 has been shown to remain at the plasma membrane when stimulated for 40 minutes with the sst2-selective agonist L-779,976 while stimulation with the non-selective agonist [D-Trp8]-SOM-14 resulted in near complete internalization of sst2A. Unpublished observations showed that following L-779,976 stimulation, sst2A fluorescence at the plasma membrane was lowest after 20 minutes before increasing and plateauing by 40 minutes. We therefore …  Lire la suite

Nous vivons dans l'ère informatique où la demande de la capacité d'information est propulsée par l'expansion exponentielle du trafic Internet. Étant donné que la non-linéarité de la fibre optique représente une dégradation qui limite la capacité de la fibre optique, le niveau de la compensation sur la non-linéarité de la fibre optique détermine la capacité du réseau de fibres optiques. En fait, les formats de modulation avancés et le traitement numérique du signal ont été utilisés récemment pour explorer la région non-linéaire de la capacité de la fibre optique. L'objectif de cette thèse est la compensation de la non-linéarité intra-canal …  Lire la suite

Au Musée Redpath de l’Université McGill, de nombreux objets de l’antiquité égyptienne sont exposés, y compris plusieurs momies. Aux côtés de celles-ci, une borne donne accès au public à un programme interactif qui présente le résultat de l’examen radiographique d’une momie mâle du Nouvel Empire. Cet element interactif de l’exposition date d’il y a dix ans; de ce fait, le matériel est vétuste et a besoin d’être remplacé. De plus, le musée souhaite améliorer le logiciel et en augmenter le contenu. Notre mémoire de maîtrise présente donc la conception et la mise en œuvre d’un nouveau logiciel interactif sur les …  Lire la suite

Cette thèse présente une analyse approfondie des écoulements visqueux permanents et oscillatoires autour des profils aérodynamiques et des ailes tridimensionnelles, ainsi que des écoulements confinés tridimensionnels à faible nombre de Reynolds. Ces travaux de recherche ont été réalisés dans plusieurs études: i) les écoulements visqueux confinés permanents et oscillatoires; (ii) les effets de séparation nonstationnaires sur les profils aérodynamiques stationnaires; (iii) l'effet de la proximité du sol sur les écoulements visqueux stationnaires et oscillatoires autour des profils aérodynamiques fixes et oscillants; (iv) les écoulements en trois dimensions autour des ailes à faibles nombres de Reynolds.La première partie présente une méthode …  Lire la suite

In this thesis we follow two directions: Zero Knowledge Protocols and the Discrete Logarithm Problem. In each direction we present the necessary background and we give a new approach for some parts of the existing protocols. The new parts are dedicated to the soundness property of the Schnorr Identification Scheme and to the security of the sum+-Protocol. Since both directions are very well-known and studied in the field of cryptography, they are presented with many details so that the new results are easy to follow. In writing this thesis we have tried to present the material in a specific order …  Lire la suite

Jaksic, Vojkan (Internal/Supervisor)  Lire la suite