McGill University Thèses et mémoires par auteur commençant par S

Parallel mechanisms are being introduced as platforms for machine tools, where stiffness and vibration supression is vital. A novel parallel architecture, called double triangular (DeltaDelta), was proposed and studied in depth by Daniali in anticipation of applications which require fast and precise motion. However, Daniali failed to find the minimal solution to the spherical DeltaDelta parallel manipulator, which he suspected is quadratic. Here, projective geometry and Grassmannian incidence relationships are used to unify the method of direct kinematic analysis (DKP) of two types of three degree-of-freedom manipulators, viz., the planar and spherical versions of DeltaDeltaPM, while preserving the geometric meaning …  Lire la suite

Definitive repair of complex congenital cardiac defects in early life has become the recent trend in pediatric cardiac surgery. This early aggressive surgical approach is to avoid the detrimental effects on the heart of chronic cyanosis, hypertrophy and volume overload which are the consequences of unrepaired congenital malformations. Adequate protection of the heart, not only during the period of corrective surgery, but also certain pre-ischemic events remain of paramount importance to the success of these operations. Profound systemic hypothermia followed by total circulatory arrest is widely used for the correction of congenital cardiac defects in the newborn. It involves a …  Lire la suite

Cette recherche est une approche qualitative basée sur des entrevues avec des étudiants en matière d'apprentissage basé sur le design (DBL). Elle vise à découvrir la valeur du DBL en tant qu'approche pédagogique dans l'enseignement supérieur (ES) en explorant l'intérêt des étudiants pour le design, les leçons qu'ils apprennent du design, les liens du design avec leur éducation et leurs aspirations. L'étude est basée sur des entrevues avec 15 participants dans six programmes différents, au niveau du premier cycle universitaire. La méthode de recherche comprends des entrevues semi-structurées pour la collecte des données, une analyse comparative constante pour l'analyse des …  Lire la suite

Pellegrino, Louis.  Lire la suite

Food insecurity and malnutrition are issues that affect approximately one in seven people worldwide and climate change threatens to increase those risks in the future. Many of the policies that address future food systems emphasize resilience - a combination of flexibility in the face of disturbance and the capacity to adapt to change. In Sub-Saharan Africa many households employ livelihood systems that are highly sensitive to change and cannot adapt well to changing environmental conditions, leaving them vulnerable and reliant on coping strategies. Wild edible plants (WEPs) are a particularly common and effective strategy for coping with food insecurity. This …  Lire la suite

The following thesis is based on my study of two candidate prostate cancer tumor markers, namely telomerase and CD9. Accordingly, the thesis will be divided in two main chapters describing the results obtained for each protein. Although these proteins are de-regulated in prostate cancer cells, little is known about their regulation and function in prostate cells. For example, telomerase is generally inactive in normal cells and reactivated in cancer cells and CD9 is a transmembrane protein that is lost as prostate cancer progresses. In chapter 2, I will show that introduction of normal human chromosomes into mouse melanoma cells can …  Lire la suite

Nicole Yee Key Li (Internal/Cosupervisor2)  Lire la suite

Intrigued by the observation that enduring, task-based water treaties have, surprisingly, emerged within protracted conflict settings that lock the riparians in a deadly embrace, I constructed an interdisciplinary theoretical framework to explain the causes of riparian conflict, and the conditions for riparian conflict resolution. Drawing on the literature from international relations, comparative politics, resource economics and public choice theory, I explain how the constraints posed by ecological forces in a conflict setting, and the political opportunities presented by a particular economic-developmental context shape the decisions of policymakers during the negotiation process that precedes regime emergence. Next, a model is developed …  Lire la suite

A hallmark of the market economy is the exit of uncompetitive firms. However, it has been demonstrated empirically that a substantial number of unproductive firms who should exit the market based on economic fundamentals manage to persist across developed countries (McGowan, Andrews, and Millot 2017a; Andrews, McGowan, and Millot 2017). The survival of this class of firms known as zombie firms presents an important puzzle as they are a drag on aggregate productivity and the broader economy. I argue zombie firm survival is driven by political actors who provide protection to zombie firms through a number of potential channels including …  Lire la suite

This thesis is a contribution to the study of the biblical interpretation of the Italian Reformer Peter Martyr Vermigli (1499-1562). Specifically researched is Martyr's use of the Jewish resources of the 1525 Bomberg Bible in his interpretation of Lamentations, Martyr's earliest surviving commentary. The form of this investigation is as follows: first, an introduction to the use of Jewish resources by Christian students of scripture; secondly, an annotated translation of Martyr's Lamentations commentary; thirdly, conclusions concerning Martyr's use of Jewish commentary. After a select bibliography, there are appendices which include a synopsis of sixteenth century Latin translations of Lamentations and …  Lire la suite

Afin d'évaluer les effets de !'exposition au fluor sur la reproduction d'oiseaux mâles, des crécerelles d'Amérique (Falco sparverius) et des cailles japonaises (Cotumix japonica) ont été traitées avec du fluor de sodium pendant une période de temps prolonge puis couplées avec des femelles non traitées. Quarante crécerelles d'Amérique males ont été assignées de façon aléatoire a un des traitements suivants: 1,65, 3,3 ou 6,6 mg NaF ou une solution contrôle de 13,2 mg NaHC03 administres par gavage oral quotidiennement pendant 45 jours. Durant la première année tous les males ont été couplés avec des femelles non traitées dès la complétion …  Lire la suite

The dynamic distribution of pulmonary ventilation was studied both theoretically and experimentally. The human lungs were simulated as two compartments driven by independent cyclic pleural pressures. The distribution of tidal volume depended primarily on the regional pressures, but dissimilar pressure swings generated sequential flows. A model of the tracer dynamics in the lung during a breath showed that the ventilation per unit volume was proportional to the time derivative of krypton-81m activity normalized by the activity itself. In gamma camera measurements, the average flow distribution was independent of frequency and tidal volume, but the flow per unit volume in left …  Lire la suite

Although carboxymethylcellulose is a newcomer among the cellulose derivatives, it is now enjoying a widespread use in such fields as detergents, drilling muds, foods, textiles, paper, paint and many others (1). Since the physical and chemical properties of cellulose derivatives cannot be explained in terms of molecular weight and degree of substitution alone, much effort has been devoted to the development of methods for determining how the substituents are distributed along the chain molecu1es of cellulose.  Lire la suite

Mercury is one of the most toxic environmental pollutants of global concern. Understanding transformation pathways among various mercury species is critical for predicting the fate, transport and potential toxicity of mercury to the ecosystems. The purpose of this research was to advance our knowledge on the photochemical reactions of oxidized mercury species with selected organic molecules by performing kinetic and product studies at near environmental conditions. The reduction of Hg2+ by small, semi-volatile dicarboxylic acids was the first to be investigated. The highest were observed in systems free of both oxygen and chloride ion with the second-order apparent rate constants …  Lire la suite

A knowledge-based expert system was developed to automatically assess the level of EEG abnormality of pediatric patients monitored in the ICU. The system receives six hours of 8-channel EEGs and classifies the background EEG as one of seven abnormality levels. A total of 188, six-hour EEGs were visually interpreted by a neurologist and used as training examples. Spectral band activity was computed; artifacts were rejected using a median filter with a hard-limiter. Quantitative variables reflecting amplitude, symmetry, Front/Back differentiation and time variability were then extracted based on the study of Pasupathy (1994). Relationships between quantitative measures and the neurologist's assessment …  Lire la suite

Gap junctions are protein transmembrane channels formed between apposing cells whose primary role is in mediating intercellular communication. This study addressed (1) the role of gap junctions in mammary epithelial cells during the transition from proliferation to quiescence, and (2) the mechanism of gap junction formation between different mammary cell types (heterocellular gap junctions). In the first part, proliferating mammary epithelial cells were induced to enter quiescence by serum deprivation or contact inhibition. Using Western blotting, we observed a dramatic reduction (up to 20-fold) in the expression of the gap junction protein, connexin43 (Cx43), during quiescence. Microinjection of the dye …  Lire la suite

The middle ear is a small air-filled cavity which contains a chain of three small bones or ossicles: the malleus, the incus and the stapes. There is a tiny bony bridge (pedicle) between the long process of the incus and the lenticular process, but little or nothing is known about the effect of the pedicle on the movements of the ossicles. The motivation of the work presented here is to improve our understanding of the mechanical behaviour at the pedicle and the incudostapedial joint, in particular the relative contributions of the two structures to sound transmission through the middle ear. …  Lire la suite

This qualitative inquiry is a close reading of the representations of public schools and schooling in HBO's television drama The Wire. I pay particular attention to the experiences of school administrators, educators, and students. The Wire draws from the ethnographic work of David Simon, a former Baltimore Sun journalist, and Edward Burns, a retired homicide detective and public school teacher. In examining the show's critiques of public schooling, I ask these questions: What types of representations of public schools and schooling are revealed in season four of The Wire? What kind of knowledge do these representations produce, and how is …  Lire la suite

Cette thèse explique et met en oeuvre la méthode des diffrences finis pour simuler la propagation de modes de guides d'ondes intgré. La méthode équidistante et non-équidistante est expliquée et mise en oeuvre. Un moteur de reconnaissance de formes est mise en oeuvre pour reconnaître la structure des guides d'ondes rectangulaire prévues par l'utilisateur sous forme d'images. Un algorithme géomtrique de maillage est développé pour améliorer l'exactitude.  Lire la suite

Caulobacter crescentus divides asymmetrically to produce two different progeny, a swarmer progeny that is replication incompetent, and a stalked cell progeny that is replication competent. Upon cell division, a cell cycle regulator protein (CtrA) was identified only in the swarmer cells, and additional circumstantial evidence links this protein to being a repressor of chromosome replication. For example, this response regulator protein binds to five specific sites in the replication origin (Cori) designated [a-e]. We carefully studied the binding characteristics of both phosphorylated (CtrA~P) and unphosphorylated forms of the protein to the five binding sites [a-e] in the replication origin (Chapter …  Lire la suite

The primary goal of this study is to develop novel metal catalyzed multicomponent reaction methods to generate imidazoles and their derivatives. This is directed towards the assembly of poly-substituted imidazoles, imidazolones and imidazole-containing pi-conjugated polymers. These products are generated in one-pot from such basic components as imines, acid chlorides, carbon monoxide, and/or organostannanes, via the use of palladium catalysis. In Chapter 2, the design of a new palladium catalyzed synthesis of highly substituted imidazoles from imines and acid chlorides is described. This reaction involves the palladium catalyzed generation of 1, 3-oxazolium-5-oxides (Munchnones); which are trapped with N-tosyl substituted imines via …  Lire la suite

The Helminthosporium disease of Portulaca oleracea L. (purslane) was first discovered and described as it occurred on purslane by Rader (59) in 1948. He proved that the disease was due to an unknown pathogenic fungus which he described briefly and named Helminthosporium portulacae nov. sp. In 1940, a diseased rose moss specimen from a private garden in Gananoque, Ontario, was sent to the Central Laboratory of the Division of Botany and Plant Pathology, at Ottawa, Ontario, for diagnosis. Various fungi were found fruiting on the specimen, but an unfamiliar one seemed to predominate. This organism was not isolated, but it …  Lire la suite

DNA replication initiates at origins with the origin recognition complex (ORC) binding and activating initiation. Although ORC specifically binds origins in vivo, it possesses no sequence specific DNA binding activity in vitro. Thus, it is thought to interact with another protein that recruits it to the origin. The heterodimeric Ku (Ku70/Ku80) protein is one candidate. Ku is an abundant nuclear protein that has recently been implicated in the initiation of DNA replication, but the mechanism by which it performs this function is yet unknown. Here, using haploinsufficient human HCT116 Ku80 +/- cells that express 25-40% Ku80 protein, the origin activity …  Lire la suite

Folate deficiency, a prevalent vitamin deficiency in America, can stem from environmental and/or genetic causes. The most common inborn error of folate metabolism is deficiency of methylenetetrahydrofolate reductase (MTHFR), which catalyzes the reduction of 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate. Severe MTHFR deficiency results in hyperhomocysteinemia and homocystinuria; patients present with developmental delay, and various neurological and vascular disorders. This thesis describes three mutations identified in the MTHFR locus in patients with severe deficiency: 1025T→C (M→T), 1027T→G (W→G), and 1768G→A (E→K). Genotype-phenotype correlations are described, along with biochemical characterization of three mutations (983A→G (N→S), 1025T→C, 1027T→G). All three mutations exert their effect by …  Lire la suite

Gray-Donald, K. (Supervisor)  Lire la suite

Qualitative and quantitative research methods were employed to evaluate the acceptability and feasibility of HIV-1 infected, urban South African mothers being able to feed their infants heat-treated expressed breast milk (HTEBM). Nutritional status assessment of HIV-infected breastfeeding mothers (n=84) indicated that maternal status was not compromised; mean body mass index 26.8 (4.0) kg/m2, triceps skinfold 14.8 (5.50) mm and hemoglobin 11.6 (1.49) g/dL. However, severely immunocompromised mothers (CD4 + < 200 cells/mm3) were more likely to be anemic. Breastmilk viral loads were also higher in mothers with lower CD4+ cell counts. Community based inquiry on the acceptability of HTEBM was …  Lire la suite

Les systèmes d'enregistrement du mouvement 3D trouvées aux laboratoires de recherche sont coûteuses et compliquées. Le Ultrasound Motion Tracking (UMT) système est léger, portable et à faible coût pour mieux répondre aux besoins de cliniques. Nous avons validé le système en comparant la précision des mouvements d'atteints impliquant le tronc enregistré simultanément avec les systèmes UMT et Optotrak. La précision du UMT a été acceptable en ce qui concerne la précision du mouvement en comparaison avec le système 'standard d'or' de Optotrak. Dans une deuxième étude, UMT a été utilisé pour détecter des déficits du mouvement coordonné chez des patients …  Lire la suite

CD109, un régulateur négatif de la signalisation du TGF-β, améliore plusieurs paramètres de la cicatrisation et réduit la réponse fibrotique lorsqu'il est surexprimé dans l'épiderme de la souris. La surexpression de CD109 dans l'épiderme entraîne une diminution de l'épaisseur dermique au septième jour de la cicatrisation, et provoque une réduction de la production de matrice extracellulaire. Nous émettons l'hypothèse que la surexpression de CD109 dans l'épiderme peut traduire ses effets dans le derme et altérer la fonction dermique. Notre objectif pour la présente étude était de modéliser l'interaction entre l'epiderme surexprimant le CD109 et les fibroblastes dermiques in vitro en …  Lire la suite

Morphogenesis of the dsDNA phages is a highly regulated process that utilizes multicomponent pathways to assemble precursors of heads and tails. These mechanisms have been extensively investigated in many phage systems but have yet to be well characterized for the transposable phages. To investigate morphogenesis in these systems, we have cloned and sequenced 4.5 kb the of the DNA of phage Mu immediately downstream of the first late promoter P lys; expressed the associated proteins; examined phage development in thin section; and refined our existing in vitro packaging assay. Previous amber mutant analysis had located the lytic and maturation genes …  Lire la suite

Reed, R. W.  Lire la suite

In this work we investigate the order of vanishing of L( s, chi) and L(s, f) (resp. rchi and rf) at the centre of the critical strip, where chi is a Dirichlet character and f is a newform of weight 2 and level N (f ∫ ∈ S2(N)^new). We show that on average rf or r chi are not large. Precisely: (1) We generalise Murty's results on the analytic rank of J0(N) to arbitrary levels N: under the RH for all L(s, f) then lim sup N→∞ f∫S2(N)new rf dim S2(N) ≤ 3/2. (2) We prove that the triangle function …  Lire la suite

Vetois, Jerome (Supervisor2)  Lire la suite

Van de Ven, Theodorus G. (Supervisor)  Lire la suite

Des chercheurs ont constaté un ralentissement et une stagnation de la transformation des pratiques de l'enseignement constructiviste, appuyé par les technologies de l'information et des communications (TIC), tant au Québec qu'à l'étranger, en raison des nombreuses contradictions qui se sont manifestées dans la structure organisationnelle (c.f. Park, 2009; Sicile, 2007). Cette étude de cas vise principalement à examiner une intervention de second ordre ou prévue, d'une durée de cinq mois, au sein d'une école qui se caractérise par sa technologie, afin de mieux comprendre l'apport de changements aux pratiques d'enseignement, passant de l'enseignement traditionnel à l'enseignement constructiviste appuyé par les …  Lire la suite

This research is intended for educational policy makers. This is an exploratory study that investigates Quebec's classrooms as a new educational reform is implemented. There are two relevant pieces of legislation in the reform that elicited this study. First, teachers are required to adopt constructivist teaching practices; second, teachers must use ICT in classrooms. The questions being addressed are: (1) What are the current challenges and benefits impacting teachers with the integration of computers in the classroom environment? (2) What do classroom practices look like given (a) in the context of Quebec's constructivist-learning environment and (b) the possibility of ICT …  Lire la suite

The fundamental biological functions of spermatogonial stem cells (SSCs) is to support sperm generation and as such the propagation of genetic material to future generations. Like other stem cells, SSCs are defined by their ability to self-renew and also generate daughter cells which are committed to differentiation (J. M. Oatley & Brinster, 2008). It has been shown that retinoic acid (RA) is quintessential in spermatogenesis; its role is most clearly seen in its absence which results in infertility (Snyder, Small, & Griswold, 2010). In vivo RA acts on undifferentiated spermatogonia transitioning them into differentiating spermatogonia, consequently RA can serve as …  Lire la suite

Jardim, Armando (Supervisor2)  Lire la suite

Industrial mill logs from 7 different hot strip mills were analyzed in order to calculate the mean flow stresses developed in each stand. The schedules were typical of the processing of Nb microalloyed, multiply-alloyed and plain C-Mn steels. The calculations, based on the Sims analysis, take into account work roll flattening, redundant strain and the forward slip ratio. The measured stresses are then compared with the predictions of a model based on an improved Misaka mean flow stress equation, in which solute effects, strain accumulation, as well as the kinetics of static and metadynamic recrystallization are fully accounted for. Good …  Lire la suite

Member Countries of the Andean Community (ANCOM) have established a supranational legal regime applicable to intra and extra-subregional air transport activities: the Andean Subregional Air Transport Integration system. This regime was established by Decisions 297 and 320 and was based on the Colombia-Venezuela Bilateral Air Transport Agreement. It revolutionizes the status quo regarding air transport. The new regime adopts the principles of multiple designation of air carriers, free determination of frequencies and capacities for scheduled air services performed with the Subregion, and complete liberalization for non-scheduled air services. It creates an "Andean subregional market" and promotes the establishment of a …  Lire la suite