McGill University Thèses et mémoires par auteur commençant par R

Goring, D. (Supervisor)  Read more

The sympathetic division of the autonomic nervous system is known to play a role in the genesis of neuropathic pain. In the skin of the rat lower lip (hairy skin), sympathetic and parasympathetic fibres normally innervate the same blood vessels in the lower dermis but do not occur in the upper dermis. However, we have shown that sympathetic fibre migration into the upper dermis occurs following mental nerve lesions (1. Compo Neurol. 422:287-296, 2000). As sensory denervation has a dramatic effect on sympathetic fibre innervation patterns in the rat lower lip skin, we decided to investigate the possible changes in …  Read more

Aggression is conserved among a large number of animal species, which allows animals to compete for food, mate and defend their territories. Aggressive behaviours can occur between two individuals within the same species. In social species such as ants, chimpanzees and humans, aggressive behaviours can also be displayed between different groups within the same species. While natural aggressiveness is important for survival and reproduction, abnormal aggressiveness can cause the waste of energy and severe injuries. In humans, escalated aggression may lead to wars and genocide. My PhD work utilizes Drosophila melanogaster as a model to study the mechanisms underlying the …  Read more

Development of climate change mitigation and adaptation strategies, particularly for engineering systems, require information on the future evolution of various climatic variables/loads, including those related to soil moisture, which are mostly obtained from transient climate change simulations performed with high-resolution climate models. Developing credible high-resolution models, particularly in the identification of biases and their causalities for subsequent improvements, is computationally expensive. This study presents an efficient machine learning framework to assist in the causal analysis of biases in climate model simulated fields at significantly reduced computational costs. The framework consists of a two-step approach. The first step involves the development …  Read more

An optical technique for monitoring the solidification of thermoplastics in an injection moulding machine was implemented. The technique uses a He-Ne laser that illuminates the mould cavity, and a photomultiplier to measure the intensity of reflected light during the moulding cycle. Data from the sensor allows tracking the injection moulding cycle development. The measured light intensity is mainly influenced by refraction and reflection phenomena at the melt-solid interfaces during solidification. Reflection occurs primarily from the opposite mould wall but the reflection intensity is a complex composite of reflective scattering and refraction from crystallites, the mould wall and as many as …  Read more

Martineau, Paul Andre (Supervisor1)  Read more

Retinal ganglion cells (RGCs) are the sole output neurons of the retina, conveying visual information to the brain. There are many different types of RGCs, but their possible roles in visual perception are not well understood. In cats, three major types of RGCs have been defined, neurophysiologically (X, Y, and W) and morphologically (alpha, beta, and gamma/delta, respectively). Y-alpha cells are cat RGCs with a large cell body and large dendritic fields, similar to parasol cells in primates. They project to the LGN, which relays to the visual cortex and respond linearly or nonlinearly depending on the visual stimuli. The …  Read more

Studies suggest that milk urea nitrogen is influenced by multiple dietary and non-dietary factors; however most studies continue evaluating those effects independently. Further information is required in order to understand the properties, variations, and applicability of milk-nitrogen fractions by the producers. The objective of this study was to use machine-learning and visualization techniques in the investigation and evaluation of multiple factors altering milk urea nitrogen. Records from the Quebec Dairy Production Centre of Expertise (Valacta) were used in the analyses. After edits, the data consisted of 2,382,043 milk test-day and feeding composition records from Ayrshire, Brown Swiss, Holstein, and Jersey …  Read more

L'optimisation de la limite du creusage est un problème de prise de décisions opérationnelles qui affecte considérablement la valeur de l'exploitation de mines à ciel ouvert. Les limites de creusage - qui sont habituellement dessinées à la main - classifient les limites de la pratique du minerai et des déchets convenant à la taille des équipements sur un niveau. Une approche d'optimisation basée sur des algorithmes génétiques a été développée dans un but d'approximation des limites optimales du creusage sur un niveau, en tenant compte des données de contrôle de teneur, des contraintes des équipements ainsi que des coûts du …  Read more

The biological cycling of silicon (Si) in terrestrial ecosystems is a key driver of long-term carbon sequestration, and terrestrial and marine productivity. A better knowledge of the effects of tree species composition on the spatial and temporal variation of biogenic silicon (BSi) in forest soils is essential to fully understand forests' effects on Si and carbon (C) cycling. In this study, I measured soil BSi concentration in the hardwood forest of the Morgan Arboretum (Montreal, QC, Canada) to understand its relationship with soil fertility parameters (pH, available P, K, Ca, Mg, Al, total C, total N, and water content), soil …  Read more

Background: Transportation is a crucial facilitator of quality of life. Most older adults drive and prefer to; however, many live long enough to experience driving cessation. Driving cessation can help improve safety for people on the road, but it can also lead to negative consequences such as depression, decreased activity participation, unfulfilled needs, and social isolation. These consequences impact quality of life. Methods: This thesis employs data from the Canadian Longitudinal Study on Aging (CLSA) to examine the reasons for driving cessation and the associated socio-demographic characteristics. Logistic regression models are used to understand the relationships between sociodemographic characteristics, driving …  Read more

We give a brief overview of the problem of lifting elliptic curves, and of the classical theory of complex multiplication. We then concretize the results of B. Gross on lifting endomorphism of formal groups from characteristic p to characteristic 0 by applying them to elliptic curves, with a view toward developing explicit numerical methods to compute the lift of the j-invariants. Chapter 1 and Chapter 2.1 are review of well-known results, while the results of Chapter 2.2 and Chapter 3 have been derived independently except where otherwise mentioned  Read more

The role of the central nervous system in the regulation of adrenal ornithine decarboxylase (ODC) activity has been studied. Medullary and cortical tissues were separated and the enzyme activities measured in vitro. Many factors affecting ODC activity were analyzed separately and in combination: pharmacological (oxotremorine, methylatropine, reserpine); surgical (splanchnicotomy, spinal cord transection); hormonal (hypophysectomy); and environmental cold exposure, restraint). […]  Read more

The possible role of endogenous opioids in the central adrenergic control of blood pressure and heart rate was studied in different strains of hypertensive and normotensive rats. In spontaneously hypertensive rats (SHR) the hypotension and bradycardia resulting from stimulation of central (alpha)-adrenoceptors by clonidine or (alpha)-methyldopa are inhibited by the opiate antagonists naloxone and naltrexone and by centrally administered (beta)-endorphin antibody. Clonidine and 1-(alpha)-methylnoradrenaline increase the release of immunoreactive (beta)-endorphin from brain stem slices of SHR, superfused in vitro. The antihypertensive effects of clonidine and (alpha)-methyldopa are similarly inhibited by opiate antagonists in steroid/salt and renal hypertensive, Sprague-Dawley rats, but …  Read more

Meguerditchian, Ari Nareg (Internal/Supervisor)  Read more

A growing repertoire of proteins is involved in the molecular events surrounding clathrin-coated vesicle (CCV) formation, which is seminal to the regeneration of synaptic vesicles in nerve terminals, as well as to more universal membrane trafficking mechanisms. Amphiphysin-I and endophilin-I are two nerve terminal-enriched proteins thought to function in CCV formation. In the first study of this thesis, we identified a novel amphiphysin-I isoform (termed amphiphysin-II), through a homology search of the expressed sequence tag (EST) database. We demonstrated that like amphiphysin-I, amphiphysin-II is highly enriched in nerve terminals, where it interacts with dynamin-I and synaptojanin-I through its SH3 domain. …  Read more

Malowany, Dr. A. S.  Read more

The von Hippel-Lindau (VHL) disease is a hereditary cancer syndrome that is transmitted in an autosomal dominant manner. The disease is characterized by the formation of highly angiogenic tumors in many organs but the main causes of mortality are renal cell carcinomas and hemangioblastomas. Mutations in the VHL protein are responsible for the pathogenesis of the disease. VHL associates with elongin Band C to form the VBC complex. The cullin 2 protein (CUL2) and ring box protein 1 (RBX1) also associate with the VBC complex to form an E3 ubiquitin ligase involved in the ubiquitination and subsequent degradation of the …  Read more

This work utilizes a spatial theory approach to meditate on postwar Japanese society and cinema. It is not a history of Japanese postwar cinema, or a survey of notable directors and genres. Rather, the focus is specifically on film and its relation to the deeper tropes of Japanese society; in particular, on how the sense of nation is affirmed and/or challenged within a postwar period of remarkable change. Understanding such a structure greatly aids in analyzing the forms and meanings within the films. The question of National Cinema, then, is approached by exploring how the interaction of spatial-temporal elements affect …  Read more

Rousseau, Simon (Internal/Cosupervisor2)  Read more

Patience, Gregory (Internal/Cosupervisor2)  Read more

As the energy dependence grows with the rapid increase in the world's population and the unprecedented technological advancements, the consumption of fossil fuels will continue to surge, resulting in deleterious consequences on many aspects of life. Hydrogen gas (H2) is a promising energy vector/carrier that can bridge the gap between the shortcomings of renewable sources and the fluctuating demand of the electrical grid. However, currently ca. 95% of H2 is produced from carbon-based sources (e.g., methane steam reforming), negating the environmental benefits of using H2 as a clean energy vector. A more environmentally-friendly option to produce “green” H2 is water …  Read more

Natural biopolymeric systems serve as a significant source of inspiration for scientists and engineers seeking to create innovative high-performance materials for various applications. For example, mussels can adhere strongly to diverse types of surfaces via the byssus, a collection of tough and flexible collagenous fibers. Previous studies highlighted the role of metal coordination in the reinforcement of their protein-based byssal threads. This reinforcement is pivotal for mussels to securely attach to rocky seashores and withstand the challenges of high intertidal zones owing to the exceptional toughness and self-healing capabilities of these fibers. Taking inspiration from this system, metal coordination-based crosslinks …  Read more

Weichenthal, Scott Andrew (Supervisor1)  Read more

Real gases consist of multiple chemical species, including oxygen, nitrogen, and hydrogen. For practical applications, a mono-species model is often used to simplify flow simulations by representing the gas with a single chemical species. However, for combustion or mixing flows where the differentspecies have different masses, or for high-speed and high-temperature flows where thermal properties such as heat capacity and enthalpy exhibit nonlinear relations with temperature, a multi-species model under a calorically imperfect assumption becomes essential for accurate analysis.In computational fluid dynamics (CFD), computational methods and modelling are carefully chosen to balance computational costs with achieving high accuracy. The multi-species …  Read more

La microscopie de fluorescence à molécule unique (SMFM) englobe un ensemble de techniques puissantes à haute résolution spatio-temporelle utilisées pour explorer le monde micro et nanoscopique, des processus biologiques au comportement des matériaux. Le principal avantage de la SMFM est sa capacité à élucider les comportements hétérogènes des molécules individuelles, un aspect souvent masqué dans les expériences conventionnelles en vrac. La performance des fluorophores et la nécessité de contourner les défis posés par la réactivité chimique inhérente (photochimie) et les processus physiques (photophysique) des états excités sont au cœur de la SMFM. La dégradation des fluorophores est principalement due à …  Read more

Nous envisageons des réseaux électriques futurs avec une pénétration beaucoup plus importante des sources d'énergie distribuées telles que les panneaux solaires photovoltaïques, les éoliennes et les systèmes de stockage d'énergie par batterie, qui sont essentiellement des sources de courant continu. Avec la prolifération des véhicules électriques, des stations de recharge rapide et des charges à courant continu telles que les centres de données, les interfaces de réseau à courant continu ont également été prises en considération. Dans cette thèse, un convertisseur à bus intermédiaire destiné à être utilisé dans des architectures de réseau à courant continu qui assistent le réseau …  Read more

Grad, Roland (Internal/Cosupervisor2)  Read more

My dissertation focuses on the rise and spread of Aboriginal mobilization in Canada between 1951 and 2000. Using social movement and social-political theories, it questions the relationship between contentious actions and formal organizational growth comparing among social movement and political sociological perspectives. In most accounts, contentious action is assumed to be influenced by organization, political opportunity and identity. Few scholars, however, have examined the reverse relationships, namely the effect of contentious action on each of these. Drawing upon time-series data and qualitative interviews with Aboriginal leaders and representatives of organizations, I found that critical events surrounding moments of federal state …  Read more

Most investigators agree that the posterior pituitary hormone has at least 3 different actions: Oxytocic, antidiuretic and vasopressor. On the other hand there is disagreement regarding the question of the existence of a single fraction having all three activities or that of 3 separate fractions.  Read more

The aim of this work was to investigate the role of CD4 + T cells, central to airway inflammation in asthma, in airway remodeling. Structural changes that occur in asthmatic airways in association with inflammation include an increase in airway smooth muscle mass, which participates in causing airway hyperresponsiveness. We aimed to gain further insights into the mechanisms that may link inflammation with remodeling using a rat model of experimental asthma. We hypothesized that CD4+ T cells drive airway smooth muscle remodeling. Adoptive transfer of CD4+ T cells from ovalbumin-sensitized rats induced increased proliferation and inhibition of apoptosis of airway …  Read more

It was shown, previously that N. crassa contains an endo-exonuclease which exist in two forms, an active form and an inactive form activated by trypsin treatment in vitro. Both of these forms were found in the cytosol and in mitochondria, but only the active form is present in the vacuoles. In the present work, it has been shown that both forms are also present in the nuclei bound to the chromatin. Active endo-exonuclease was previously implicated in DNA repair and in this study additional evidence was obtained in further support of such a role: (i) the mutagen sensitive uvs-3 mutant …  Read more

DNA replication initiates at replication origins and involves the ordered assembly of a pre-Replicative Complex (pre-RC), consisting of the ORC1-6, Cdc6, Cdt1 and MCM2-7 proteins. The Ku heterodimer (Ku70/Ku80) was previously implicated in the pre-RC assembly but its mechanism of action is yet unknown. Here, Ku is shown to form a complex with DNA topoisomerase IIβ (topo IIβ) both in vitro and in vivo and target it onto replication origins. The enzymatic activity of topo IIβ creates transient, origin-specific dsDNA breaks thus affecting the DNA topology during pre-RC assembly. Pharmacological inhibition of the topo II activity interferes with the pre-RC …  Read more

Mathematics 436 is the advanced mathematics course offered to students in secondary IV in the province of Quebec. Although the course is designed to challenge students in the advanced stream, it has produced a high number of failures. This study examines the relationship between mathematics anxiety and achievement in Mathematics 436. Fifty-six students from an English high school on the island of Montreal took part in the study. The Mathematics Anxiety Rating Scale for Adolescents was used to measure the level of mathematics anxiety experienced by the students. In addition, grades from the previous year in mathematics were obtained, as …  Read more

Antoniou, John (Internal/Supervisor)  Read more

Contexte: MI est une approche de counseling fondée sur des preuves visant à provoquer un changement de comportement, où les cliniciens cherchent à renforcer la motivation personnelle du patient pour le changement. Bien que MI ait été utilisé efficacement pour le changement de comportement, son application dans l'éducation dentaire n'a pas été étudiée.Objectif: Cette revue vise à évaluer la portée de la mise en œuvre de la formation MI dans l'éducation dentaire.Méthodologie: Nous avons utilisé la checklist PRISMA-ScR (Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews) et le manuel mis à jour de l'Institut Joanna Briggs …  Read more

Thermal processing schedule for low acid foods (LAF) is more severe than that for acid or high acid foods (HAF) because of the effectiveness of pH (pH < 4.5) associated with HAF to control the growth and activity of microbial spore forming bacteria. Hence, the hypothesis that if the LAF can be acidified (ALAF) to bring their pH to below 4.5, they can be processed like HAF. This permits the processing of ALAF under pasteurization conditions providing the opportunities for milder processing. The main objective of this study was to evaluate the quality advantages of acidified low acid food thermal …  Read more

Two complex wastes were considered for biological conversion into a marketable product. One waste, peat runoff water (the waste-water that remains after the mining of peat), was found to be unsuitable for biological conversion to any product since it contained an insufficient quantity of carbon. The other waste, NVR (non-volatile residue, the major waste from the manufacture of nylon 6$ sp prime 6 sp prime$), was found to be a suitable carbon and energy source for the production of PHB (poly-$ beta$-hydroxybutyric acid) by Pseudomonas cepacia ATCC 17697. A general approach to the development of complex toxic wastes as fermentation …  Read more

Paul Lasko (Supervisor1)  Read more

Isotope shifts of twenty-two isotopes of strontium, $ sp{78}$Sr to $ sp{100}$Sr excluding $ sp{99}$Sr, and three isomers of strontium, $ sp{83 rm m,85m,87m}$Sr, have been measured using laser spectroscopy. The nuclear spins, magnetic and quadrupole moments, have been extracted from the data for all odd isotopes. The changes in mean square charge radii have also been evaluated for all isotopes and isomers. The changes in mean square charge radii, which are compared to the predictions of the droplet model and Hartree-Fock plus B.C.S. calculations, show a pronounced shell effect at the closed neutron shell at N = 50 and …  Read more

Transposable elements (TE) are repetitive sequences that have the ability to replicate within the genome. They make up about 50% of the human genome, but until recently it was believed that they were selfish sequences with no role in normal genome function. However, recent research has shown that many TEs play an important role in genomic regulation. TEs make up a significant proportion of long non-coding RNA (lncRNA), including several that have experimentally validated functions in embryonic stem cells. While this work has greatly changed the scientific communities' view on TEs, the majority of expressed TEs still have no known …  Read more

As indicated by the title, the purpose of this thesis is to study the consequences, both social and emotional, for the family unit when it is confronted with the problem of adjustment to the presence of an educable feeble-minded child. An attempt will be made to study the factors which influence the success or failure of this adjustment in relation to the interplay of personalities within the family and in terms of some of the broader environmental influences. [...]  Read more