McGill University Thèses et mémoires par auteur commençant par T

Disc degeneration is a major factor in the onset of chronic low back pain. Exercises and medication can reduce the symptoms of pain, but if it becomes too severe the diseased disc must be removed and the vertebrae fused. Vertebral fusion is an invasive procedure which does not always prevent the recurrence of pain and has been linked with early degeneration of intervertebral discs adjacent to the fused segment. No therapy is yet available to repair the disc tissue in the early stages of degeneration or to prevent the progression to a painful state and the need for vertebral fusion. …  Read more

Fixed-vector saccades obtained upon electrical stimulation--while the eyes are steady--of any central oculomotor system structure can be derived from 2 different signals: (1) a retinal error signal, directing the eyes toward a specific location relative to the retina; (2) a motor error signal determining the movement vector itself. Theoretically, the two mechanisms can be segregated by delivering the stimulation during a naturally-triggered saccade (colliding saccade paradigm, Schlag-Rey et al., 1989), thereby creating a difference between the eyes' position at stimulation onset and their position at saccade outset. If derived from a retinal error signal, the electrically-evoked vector trajectory should be …  Read more

Lemay, Jean-François (Supervisor2)  Read more

Les muscles squelettiques constituent environ 40 % de notre masse corporelle totale et contribue à la régulation du métabolisme, la locomotion, la respiration et la posture. La formation des muscles squelettiques (la myogenèse) est un processus étroitement régulé par l'expression de facteurs de régulation myogéniques (MRF) tels que MyoD, Myogenin et Myf5. La protéine de liaison à l'ARN (RBP) HuR, un régulateur post-transcriptionnel, favorise la myogenèse en s'associant à des éléments riches en AU (ARE) situés dans la région 3' non traduite (3'UTR) des messages codant pour les MRF, conduisant à leur stabilisation. Ces données, décrites dans mon premier chapitre, …  Read more

Les récepteurs reliés aux récepteurs de l'estrogène (ERRs) sont ubiquitaires et constitutivement actifs et le rôle joué par les modifications post-traductionnelles sur leur activité transcriptonnelle est peu connu. Nous avons démontré qu'un motif consensus de sumoylation phospho-dependente (PDSM) situé dans le domaine N-terminal diminue l'activité transcriptionnelle des ERRs sur des promoteurs à élements de réponses multiples grâce à un mécanisme de contrôle de la synergie. Nous avons aussi établi que les ERRs intéragissent avec la E3-SUMO-ligase PIASy et que cette dernière promouvoit la sumoylation du ERRα de manière phospho-dépendante. De plus, en montrant que la forme sumoylée endogène de ERRα …  Read more

Stewart, R. K. (Advisor)  Read more

The first objective of this research was to evaluate oxidation-reduction potential (ORP) as an indicator of effective iron removal in a biological process and to determine its relationship to dissolved oxygen (DO) and residual iron in the filtered water. Biological removal of iron to produce drinking water was established on one full-scale and two pilot-scale plants at two sites in France. Results show that below a minimum DO concentration of approximately 0.3 mg/L, residual iron concentration was related to ORP in the filtered water. Above the minimum DO requirement, ORP on the order of approximately 500 mV consistently reflected effective …  Read more

Vigneault, R. (Supervisor)  Read more

This thesis studies the socio-political evolution of Nunavut, a proposed political entity in the Canadian Arctic, and tries to pinpoint its potential impact and influence for Canada, nationally and internationally. This study of political geography is done by way of discourse and content analysis of Inuit publications (Inuit Today, Nunavut Newsletters) and governmental documents (Hansard, the Gazette of Canada, etc). This analysis covers a time-period of 16 years, from the foundation of the Inuit Tapirisat of Canada (ITC) in 1971 to the last Conference of First Ministers on aboriginal rights in 1987. This time-period is subdivided into three segments of …  Read more

The literature on formative evaluation advocates the use of both subject matter and learner experts to review instructional materials, yet there has been little research to support this recommendation. The present study investigates the distinguishing characteristics of these two expert reviewers, in particular the type and amount of oral feedback they produced and the cognitive processes they engaged in. The think-aloud method was employed to obtain feedback about a six page instructional unit from eight experts; four subject matter and four learner experts. Comments from the experts were transcribed, segmented and coded according to three coding systems. Results indicated that …  Read more

Mongrain, Rosaire (Supervisor2)  Read more

This thesis investigates the design, simulation, fabrication and testing of electro-optic beam scanners in domain inverted LiTaO3 . To build these devices, a process of fabrication was developed including the construction of an electro-optic poling station for ferroelectric domain inversion of LiTaO3. This fabrication process was used to construct electro-optic prism beam scanners, which were designed and simulated to provide voltage controlled deflection of a collimated laser beam at 1310nm. Two electro-optic scanners were tested yielding linear deflection up to 1.064° and 0.986° at 1500V; agreeing well with simulation. Both scanners were found to have insertion losses of 1.7 dB …  Read more

The present thesis deals with the successful introduction of a second-moment closure turbulence model into a computer program using the Finite Element Method to solve the Navier-Stokes equations. The implementation presented has the advantage of using an equal interpolation for all the variables. It is also very economical in terms of the amount of memory required from the computer, since a fully decoupled formulation has been adopted, along with an iterative solver which permits to store in memory only the non-zero coefficients of the linear system of equations to be solved. Specialized elements are used to avoid resolving the near-wall …  Read more

Les régions Nordiques sont affectées disproportionnellement par les changements climatiques, avec l’Arctique se réchauffant deux fois plus rapidement que la moyenne globale. Considérant l’augmentation de température projetée, les animaux arctiques et subarctiques risquent de subir de forts effets indirects et directs des changements climatiques. La physiologie animale a le potentiel de révéler rapidement les signes avant-gardistes de changements de population imminents. Identifier rapidement les facteurs qui influencent les coûts métaboliques ainsi que les réponses physiologiques causées par le stress thermique d’un individu est crucial afin de mieux comprendre les contraintes auxquelles les animaux feront face dû aux changements climatiques. Les …  Read more

Life is characterized by its movement, somewhat independent of the milieu surrounding its substance. This movement can be perceived in time by a succession of changes which can be computed to yield a velocity in a certain direction and, by addition of quantitative analysis, a rate. [...]  Read more

Des policiers patrouilleurs travaillant par quarts ont été étudiés dans un groupe intervention ou dans un groupe contrôle avant, pendant et après une série de 7 quarts de nuit consécutifs de 8 à 8.5 heures chacun. L'intervention comportait 3 volets : 1) utilisation de photothérapie pendant les quarts de nuit, 2) port de lunettes orangées au lever du soleil et 3) horaire régulier de 8 heures de sommeil/obscurité diurne. Les policiers du groupe contrôle ne recevaient aucune consigne particulière. L'intervention visait à améliorer l'adaptation circadienne des policiers au travail de nuit. Des données ont été récoltées en ambulatoire et en …  Read more

Methylenetetrahydrofolate dehydrogenases are expressed in mammalian cells and are required for the interconversian of one-carbon substituted folates. The trifunctional NADP-dependent dehydrogenase-cyclohydrolase-synthetase is localized in the cytoplasm whereas the bifunctional NAD-dependent dehydrogenase-cyclohydrolase is expressed in mitochondria suggesting they play different metabolic roles. Insect tissues also express both proteins but when immortalized into cell lines, the trifunctional enzyme is not detectable and the bifunctional enzyme is localized predominantly in the cytoplasm. The change in localization coupled with the observation that insect cell lines are not purine auxotrophs, indicate the NAD-dependent dehydrogenase now fulfills the role of interconverting one-carbon units when the NADP-dependent …  Read more

This thesis investigates the implementation of lazy functional programming languages on parallel machines using a novel approach to strictness analysis called "abstract demand propagation" and examines the impact of laziness on parallelism. Although some work on strictness analysis using demand propagation has been done before, the present work is original in that it gives a precise interpretation of the notions of demands and demand propagation using non-standard denotational semantics. The intuition behind the notion of (abstract) demand propagation is that it can be seen as a form of (abstract) inverse computation. This form of strictness analysis has been incorporated into …  Read more

The brain can be explored while a subject executes different tasks. Such techniques are commonly referred as activation studies. The regions of the brain involved in a particular task can be located by comparing regional differences in tracer concentration to a control state. Group of neurons in the brain form complex logical circuits and their activities increase while they interpret a stimulation. These neuronal activities require glucose and oxygen and these substances travel in the blood following hemodynamic rules. Many factors influence the hemodynamic response induced by brain activation (FRIBA), but certain aspects of its temporal behavior are still unclear. …  Read more

Ce memoire tentera de decrire ce que fut l'ideologie defendue par le Shah Mohammad Reza Pahlavi d'Iran (1919-1980). Malgre que le Shah n'ait pas lui-meme ecrit ses positions politiques, il adherara a ce systeme de pensee qui pourrait avoir toutes les caracteristiques d'une ideologie. Ce systeme, qui a domine la vie politique iranienne pendant pres de trente ans, est fonde sur trois principes, soit la tradition monarchique iranienne, la constitution de 1906 et la revolution blanche. Ces trois fondements devaient permettre le developpement accelere de l'Iran et qui se traduit par une modernisation de la societe ainsi que par une …  Read more

The various transformations that Quebec society was undergoing throughout the 1980s are reflected in the dramaturgy of the period, notably in the critique of nationalist discourse, and in the writing of hitherto marginalized groups such as women, immigrants, and gays and lesbians. The tensions within the family unit are one of the leitmotivs of Quebec theatre in the 1980s, which usually represents the mother either as a sort of monster who suffocates her children, or as a victim of the Law of the Father. When a woman decides to speak and to redefine motherhood, this dual model of the "patriarchal …  Read more

La robotique passe au delà des applications industrielles contrôlées pour s'étendre au monde réel. Des véhicules autonomes tout-terrain aux robots nettoyant la vaisselle, les algorithmes doivent permettre l'adaptation à des environnements inconnus. La planification sous incertitude permet de raisonner sur ce que le robot ne sait pas et sur ce qu'il convient de faire pour y remédier. Cependant, les méthodes modernes d'apprentissage automatique qui ont pris le dessus ces dernières années manquent grandement de cette capacité. Cette thèse aidera à combler le fossé entre le monde de la planification en cas d'incertitude et l'apprentissage profond, permettant aux robots de planifier …  Read more

This thesis critically examines the One Laptop Per Child (OLPC) organization in the context of Rwanda‘s socioeconomic development plans for the year 2020. OLPC is a relatively new, large-scale development organization dedicated to the improvement of education in the world‘s poorest countries through the distribution of laptops specially designed for children. Rwanda is one of the poorest countries to have signed on the program since its founding in 2005, and ranks in the top five subscribers, having purchased 110,000 laptops for distribution among primary school students. The Government of Rwanda is committed to establishing a middle-income economy on the basis …  Read more

La conception de jeu est l'art d'élaborer un système interactif. Les concepteurs de jeux construisent des systèmes qui sont principalement composés de règles. Ces dernières décrivent comment le contenu interagit avec le joueur. Les concepteurs de jeux souhaitent façonner le jeu, cette synergie entre les joueurs et les règles. Durant ce processus, ils cherchent à comprendre et valider cette intéraction. Usuellement, cette information est obtenue par l'introduction de testeurs humains qui testent, jouent et explorent le jeu en conception. Cette thèse propose d'introduire des techniques de calcul informatique dans le processus de création de jeux, afin de créer des joueurs …  Read more

Walter, H. (Supervisors)  Read more

Class I alpha1,2-mannosidases (glycosylhydrolase family 47) form the Man5GlcNAc2 substrate for the synthesis of complex and hybrid N-glycans that are absolutely required for mammalian development. A human alpha1,2-mannosidase cDNA encoding endoplasmic reticulum alpha1,2-mannosidase I was characterized. This enzyme hydrolyses the terminal middle arm alpha1,2-linked mannose residue of Man9GlcNAc2, thus forming Man 8GlcNAc2 isomer B. It has been implicated in targeting misfolded glycoproteins for degradation. Furthermore, two novel human Golgi alpha1,2-mannosidase cDNAs, IB and IC, encoding distinct activities that trim Man9-8GlcNAc2 to Man5GlcNAc2 were characterized. The Golgi alpha1,2-mannosidases do not form Man8GlcNAc2 isomer B and are thus complementary to the endoplasmic …  Read more

Xylanase production from a Bacillus subtilis gene cloned into a strain of Escherichia coli was measured. Although this gene was expressed in E. coli at several temperatures, efficient normal xylanase secretion did not occur, the observed protein release apparently depending on cell leakage or lysis. Screening for a better microbial protein secretor free of cellulase selected B. cereus #259. The strain had wild plasmids that were hard to eliminate using acridine orange and elevated temperature curing techniques. While still bearing 5 wild plasmids, attempts to transform B. cereus #259 were unsuccessful using conventional methods and electroporation. Another strain, B. cereus …  Read more

A new dynamic service model based on granular material rheology is presented. The service model is coupled to both a mixed-layer ocean model and a 1-layer thermodynamic atmospheric model which allows for an ice-albedo feedback. Land is represented by a 6-meter thick layer with a constant base temperature. A 10-year integration including both thermodynamic and dynamic effects and incorporating prescribed climatological wind stress and ocean current data was performed in order for the model to reach a stable periodic seasonal cycle. The commonly observed lead complexes, along which sliding and opening of adjacent ice floes occur in the Arctic sea-ice …  Read more

This thesis considers the dimensional analysis theory in engineering. A Knowledge-Aided Design Tool is presented which permits the solution of many aspects of Dimensional Analysis for electromagnetics. The KAD Tool was coded in the language Lisp with Allegro Common Lisp in a Microsoft-Windows environment on a PC with a 486 microprocessor. It represents 10 196 lines of code. The mathematical functions are supported by the mathematical libraries of the software MAPLE. A menu with nine choices corresponding to nine functionalities of Dimensional Analysis is offered to the user.  Read more

In this thesis, we add a new vectorial particle to the standard model, a new particle that has the special property of having a vacuum state breaking Lorentz invariance and, therefore, CPT invariance. At the level of energy of the world we live in, this particle is expected to be in this vacuum state and we therefore should see around us some phenomenon that do not respect Lorentz invariance that comes from the interaction of this vectorial particle with ordinary matter. This thesis is presented in two parts. In the first part, we write every possible term involving our new …  Read more

The theoretical prediction of the value of the cosmological constant is far from being in accord with observations. One way to try to solve this problem is to use a scale invariant theory, however, no standard Lagrangian is truly scale invariant. In this thesis, we try to obtain a scale invariant Lagrangian by adding a suitable counterterm to the Lagrangian for the $ lambda phi sp4$ model. We then apply this technique to different models to see if this method can be applied for very different situations. We also check if flat directions in a scale invariant potential get lifted …  Read more

Les glies sont connues comme pouvant intégrer et propager l'information via une augmentation de leur concentration de calcium interne dépendante de l'activité neuronale. Des études in vitro ont également démontré que les glies ont des filopodia motiles. Nous avons effectué une étude sur une population de glies radiales provenant du tectum optique de têtard de Xenopus laevis qui comme les astrocytes montrent une activité calcique qui est dépendante de l'activité neuronale. Aussi, nous avons fait de l'imagerie en temps réel de ces cellules exprimant du EGFP-F in vivo. Nous avons observé que ces cellules ont des filopodia très motiles et …  Read more

The Dystroglycan (DG) complex is a receptor for laminin and is expressed in a variety of tissues. DG functions to maintain cell polarity via interactions with extracellular matrix (ECM) and cytoplasmic proteins. DG is expressed from a single gene encoding a pro-peptide cleaved into two distinct subunits: the ligand-binding alpha-dystroglycan (alpha-DG) and the transmembrane beta-dystroglycan (beta-DG). Both subunits associate non-covalently and form the core of the dystrophin-associated protein complex (DAPC). The DAPC stabilizes membrane proteins and its function is necessary for cell polarity and survival. The DG complex is thought to function as a classical single-pass transmembrane receptor where ligands …  Read more

Since the beginning of the history of aviation, the use of aircraft for military purposes revealed an efficient and dangerous weapon in the arsenal of a State. First it was used as observatory post, and then the aircraft took a more active role in combat until it became a destructive and deadly weapon. The definition of military aircraft in international law is not clear as States only wish to regulate international civil air navigation and not state aircraft. On the other hand, the Law of armed conflict defines the status of every aircraft with their respective duties and rights in …  Read more

The potential relationship between the Epstein-Barr Virus (EBV) and the Human Immunodeficiency Virus type 1 (HIV-1) in lines of EBV-carrying B cells that had been super-infected by HIV-1 was investigated. We found that such cells can produce high levels of viral particles, over long periods, with a minimal cytopathic effect and were less susceptible to HIV-1 infection than primary cultures of human peripheral blood mononuclear cells (PBMC). We also investigated whether an alternative receptor, other than the well-known CD4 receptor, could permit HIV-1 infection of B cells immortalized by EBV. We detected a mechanism of complement-mediated antibody-dependent enhancement of HIV-1 …  Read more

This thesis investigates the representation of Possession both in the lexicon and syntax within the Government and Binding framework. The relevant data come primarily from nominal and copular possessive constructions in French. It is argued that the canonical realization for possessive NPs in French is the postnominal dative construction: (N NP$ sb{ rm +DAT /}$). Such dative phrases need not be governed by the licensing head; dative case is a default Case in French and the dative NP can be licensed under predication. This follows from the dyadic nature of the possessive relation which triggers binary branching at all levels …  Read more

The Williamson's Diamond Mine is at Mwadui, Tanganyika Territory (British East Africa), longitude: 30°30' east, latitude: 3°30' south, 235 miles south of the equator. (See maps pp.la-2a). It is approximately 60 miles south of Lake Victoria ,and 420 miles due west of Mombasa harbor in Kenya Colony; it is 18 miles north-north-east from the administrative center of Shinyanga in the district of the same name. The mine area occupies approximately 9 to 10 square miles, and lies at an elevation of 4,000 ft above sea level.  Read more

The purpose of the present work is to present to the Grenville student an idea of the general structure at a scale of 8 miles to the inch, along with a description of the broad tectonic features and relationships existing between many physiographic and geologic components of the whole belt. The work was originally planned to include Ontario as well but since J. Tuzo Wilson undertook the compilation of the structure north of the 45°30’ parallel (with far better means than the writer had at its disposition such as aerial photographs, drauftsmen and secretaries) the part of Ontario that is …  Read more

Manoukian, Setrag (Internal/Supervisor)  Read more

This thesis addresses the consequences of the last glaciation on the distribution and genetic diversity of arctic flora. The principal aim is to infer the full-glacial and postglacial migrational history of Dryas integrifolia M. Vahl. (Rosaceae) from the intraspecific phylogeny of cpDNA haplotypes along with pollen and macrofossil distribution data. The results suggest that four refugia existed during the last glaciation and that each served as significant sources of recolonization when the ice retreated. The two most important refugia are located in the northwestern Arctic (Beringia and the High Arctic), with two other refugia located southeast of the ice sheet …  Read more

A sample of 410 single neurons were studied in the primary somatosensory cortex of halothane anesthetized cats. Basal forebrain stimulation affected the responsiveness of 63% of 80 somatosensory cortical neurons. Fifty-three percent were facilitated, 10% were inhibited leaving 37% not affected. All the effects observed had a long-term duration ranging from five minutes to more than one hour. These long-term effects were antagonized by atropine in 86% of the 22 neurons tested. An unusually broad distribution of sampled somatosensory neurons skewed toward lower layers was attributed to the stimulation of the basal forebrain. Basal forebrain stimulation also increased the proportion …  Read more

Motor response selection is the process by which an intention to act is transformed into an action; this multifaceted process occurs at the interface between cognitive and motor systems. Despite the importance of response selection, the nature and neural implementation of this process is still a subject of debate (Thompson-Schill et al, 1997; Botvinick et al., 2001; Rushworth et al., 2004; Nachev et al., 2007). While previous research has demonstrated that the selection of finger movements relies on a distributed network involving premotor and prefrontal areas, the specific contribution of these regions, however, remains unclear. It is also unclear if …  Read more

The problem investigated in this thesis is that of giving intermediate-level vision researchers adequate parallel processing tools for their work, where data and computational structures do not fit the SIMD execution model, but require a MIMD execution model instead. The contribution of this thesis is a comparison of 3 general-purpose MIMD parallel processing systems as tools for intermediate-level vision, by evaluating them against criteria which capture the essential issues in programming intermediate-level vision algorithms on such machines. According to my criteria, the best-suited of the 3 systems is composed of the Id functional language running on the Massachusetts Institute of …  Read more

The sequential gathering and fusion of surface measurements in order to obtain a globally-consistent parts-based object representation is of prime importance to object modeling, but presents some challenges. Traditionally, pixel-based techniques such as view correspondence are employed to obtain refined motion-parameter estimates between observations and a nearest-neighbour approach is used to map segmented sets of measurements to part models. Since a hard decision is made after each observation, these methods tend to fail when events such as self-occlusions, large variations in viewpoint or spurious measurements introduce ambiguity in the mapping between measurements and part models. In order to cope, the …  Read more