McGill University Thèses et mémoires par auteur commençant par Y

A cell is a highly ordered and compartmentalized place with intracellular organelles, including mitochondria and peroxisomes, that carry proteins, lipids and signals throughout the cell. The importance of mitochondrial and peroxisomal homeostasis to normal human development and physiology is highlighted in rare or common disorders where mitochondria and/or peroxisomes are impaired. They share a number of proteins in common, and there are vesicle-based deliveries of proteins from mitochondria to peroxisomes both in a steady state and for the formation of newborn peroxisomes. Peroxisomes play a central role in metabolism and signalling, pathways which are often highly tuned to the biochemical …  Read more

First, we review the basics of baryogenesis and models for baryogenesis in the early literature. Then, we discuss the main theme in this thesis, electroweak baryogenesis, which utilizes the electroweak phase transition. We present how the phase transition can be used to achieve baryogenesis. Next, we develop our model, which is the Standard Model with a singlet field coupled to the Higgs doublet negatively and to the right-handed neutrinos. It is a simple extension of the singlet Majoron model. We focus on numerical analysis of the model. Parameter space satisfying all the conditions are found and relevant quantities, such as …  Read more

Postmodernist texts by non-white authors consistently challenge accepted theoretical discourses with some notion of race or ethnicity. Until recently however, race as a unique category for theoretical investigation has remained largely unexplored. The author here outlines how both a variety of theoretical disscussions about race and ethnicity, about difference, and about experience, have formed the basis of how race is currently talked about in postmodernist discourse and how these various postmodernist discussions about race and difference may both enrich and be enriched by a theoretical examination of French poststructuralist theory. Employing the popular Benetton ads as a vehicle for theorizing …  Read more

This dissertation is concerned with surveillance, which refers to the monitoring and supervision of populations for specific purposes. Of special interest we the ways in which new technologies are augmenting the power of surveillance in the late twentieth century, and therefore influencing the privacy debate. Three things are noted about this. First, large-scale surveillance by bureaucratic organizations is a product of modernity, not of new technologies. This is evident from Part I of the dissertation, which argues that increased surveillance capacity comes as a result of specific economic and political circumstances that favour the use of technological systems of particular …  Read more

A new type of quadruped robot has been developed, the Scout class. Each leg utilizes only one actuated degree of freedom (as opposed to a typical three) to reduce complexity and cost. The design of the first of these robots, Scout I is presented. In modelling Scout, impacts are assumed instantaneous with angular momentum being conserved about the impacting toe. Stance phases are modelled as a double inverted pendulum with one input and a pin joint with the ground. Walking controllers requiring a minimum of sensing are then developed and examined both in simulation and experiments. Small errors in impact …  Read more

The flexible partition, one of the main components of the flexible housing schemes in West European countries exhibited a comparative technological lack. This research investigated the adaptability of selected commercial flexible partitions available in the North American market to residences since the most realistic way to influence the technological process was to start from the known products and developing them in an innovative direction. The consequences of the proposed sectoral transfer were seen as immediate and long term effects and categorized into three groups of constraints: legal, technological and marketing constraints. The context of evaluation was drawn, and the performance …  Read more

Le cancer implique des mécanismes complexes affectant le cycle cellulaire,l'apoptose et la sénescence. La protéine p53, qui est très étudiée, est fortement impliquéedans la modulation du développement des tumeurs. Pour cette raison, il y a eu beaucoupd’intérêt à cibler cette protéine pour de nouvelles thérapies anticancéreuses. Cependant,plusieurs complications réduisent l'efficacité de ces traitements dans les milieuxcliniques, comme le développement d’une résistance au traitement. Il est maintenantnécessaire de trouver de nouvelles cibles qui pourraient induire la sénescence cellulaired'une manière indépendante de p53. Une de ces cibles d'intérêt est la protéineZMPSTE24; nativement, cette protéine est impliquée dans l'étape de clivage final dutraitement …  Read more

Accurate surgical navigation for pedicle screw implantation significantly reduces the complication rate in spinal fusion surgeries. To achieve accurate navigation based on preoperative computed tomography (CT), accurate patient-to-image registration is necessary. However, current manual registration techniques are invasive and greatly prolong operative time. To resolve these shortcomings, automated patient-to-image registration through tracked intraoperative ultrasound has been proposed, but existing ultrasound-CT registration techniques are limited and not ready for clinical application in spine surgeries. This thesis presents the development of a technique for ultrasound-CT image registration of vertebrae that satisfies the practical requirements of being automated, accurate, robust, reasonably fast and …  Read more

Cette thèse analyse les règlementations actuelles de l'économie de covoiturage en Chine et aux États-Unis en examinant les pratiques légales et les règles de ces deux pays, mais aussi du Royaume-Uni et de plusieurs provinces du Canada, y compris l'Ontario et Alberta. L'analyse débute en décrivant le développement de l'économie de covoiturage et en identifiant les défis pratiques et théoriques qu'il pose pour le cadre réglementaire actuel. Il y a trois participants majeurs dans les services de covoiturage modernes : les conducteurs de véhicules privés, les passagers et les entreprises transnationales (STN). À cause des incertitudes légales entourant les relations …  Read more

Triple negative breast cancer (TNBC) is associated with aggressive features and poor prognosis. Despite recent research leading to new therapeutic options, the clinical outcomes for TNBC patients are complicated by limited treatment options. TNBC patients cannot be treated with hormone therapy or anti-HER2 target therapy because they lack the expressions of ER, PR and HER2. Accumulating evidence has shown that TNBC cells are enriched in breast cancer stem cells (BCSCs), which are thought to be responsible for therapy failure and tumor relapse. We investigated the molecular mechanism by which TGFβ ligands regulate stemness in TNBCs. We found that TGFβ acts …  Read more

Sarkar, Mekhala (Supervisor2)  Read more

For new manual wheelchair (MWC) users, mastering safe and efficient propulsion technique is critical, as poor technique elevates risk for chronic upper limb pain and injury. Virtual reality (VR) simulators allow users to practice such tasks in a safe, controlled, and realistic environment. Additionally, augmented feedback (AF) may be provided in order to optimize motor learning. The objective of this thesis was to investigate the effects of providing AF with various delivery schedules on motor learning of this complex skill, as well as to determine whether a propulsion technique learned in a virtual environment transfers effectively to real-world, over-ground propulsion. …  Read more

Hydroxyurea was used as a model teratogen to investigate the role of oxidative stress and stress-response pathways in mediating developmental toxicity. When administered to pregnant mice during early organogenesis, hydroxyurea induced fetal death and growth retardation, as well as external and skeletal malformations. The malformed fetuses displayed hindlimb, vertebral column, and tail defects. Hydroxyurea treatment enhanced the production of 4-hydroxynonenal, a lipid peroxidation end product, in malformation sensitive regions of the embryo. Depletion of glutathione, a major cellular antioxidant, specifically enhanced hydroxyurea-induced malformations and elevated the region-specific production of 4--hydroxynonenal protein adducts in the embryo, without affecting the incidence or …  Read more

Carbonaceous mesophases are discotic nematic liquid crystals that are spun into high performance carbon fibers using the melt spinning process. The spinning process produces a wide range of fiber textures and cross-sectional shapes. The circular planar polar (PP), circular planar radial (PR), ribbon planar radial (RPR), and ribbon planar line (RPL) textures are the most frequently observed in industrial fiber making. This thesis presents, solves, and validates models of mesophase fiber texture formation based on the classical Landau-de Gennes theory of liquid crystals, adapted here to carbonaceous mesophases. The model captures the microstructure and the formation of the four (PP, …  Read more

In value-based decisions, an unavailable alternative can influence choices between two available options. Such influences, known as distractor effects, violate economic rationality because the distractor should be irrelevant to the decision. Such violations offer insights into the neural and cognitive processes underlying decision-making. There is an ongoing debate about whether the presence of a highly rewarding distractor facilitates or impairs optimal choices, with opposite findings in different studies, and computational models with contrasting predictions. We propose that different evaluation strategies might explain the seemingly contradictory findings in prior work. There is evidence of behavioral and neural distinctions between two approaches …  Read more

Les régulateurs épigénétiques jouent un rôle important dans le contrôle de l’expression des gènes dans l’ensemble des cellules eucaryotes. La BRPF1 est un régulateur épigénétique plurivalent qui reconnaît non seulement des marques d'histone spécifiques, mais fonctionne également comme un échafaudage pour former des complexes sous-unités multiples stoechiométriques avec l'histone acétyltransférase MOZ, MORF ou HBO1. Par son domaine de liaison à l'histone H3 et d'autres domaines, BRPF1 détermine la spécificité de substrat de ces trois histones acétyltransférases. BRPF2 et BRPF3 sont analogues à BRPF1. Nous avons récemment signalé que Brpf1 du souris joue un rôle essentiel dans le développement pré et …  Read more

L'expression des gènes est fondamentalement contrôlée par la régulation spatio-temporelle de multiples mécanismes au niveau de la transcription, de la traduction et de la dégradation des protéines dans les cellules. Fait important, la régulation des gènes nécessite un complexe protéique d'ordre supérieur pour interpréter les états de modifications post-traductionnelles des histones de la chromatine. Les modifications des histones constituent un important mécanisme épigénétique dans le remodelage des structures dynamiques de la chromatine et en réponse à divers besoins cellulaires pour l'activation ou la répression de l'expression génique. L'acétylation des histones, réalisée par les histones acétyltransferases (HATs), est l'une des modifications …  Read more

Humans are sensitive to the presence of other people, as well as their interactions: for example, two individuals are detected faster when facing towards (vs. away from) each other. We asked if this perceptual preference for facing individuals in social groups might be modulated by group size, being most pronounced for small groups which are most common in everyday life. In three preregistered experiments, participants searched for facing or non-facing groups, with group size varying from two to eight. Facing groups were found faster than non-facing groups — but only for groups up to five people (Experiment 1). This effect …  Read more

A growing accumulation of experimental evidence indicates that lignin is a polymerization product of polyfunctional phenolic bodies. One of the most characteristic properties of phenols is the Kolbe reaction, whereby they are carboxylated by treatment of the alkali metal salts with carbon dioxide. If carboxyl groups could be introduced into the aromatic nuclei of lignin by the same method, it might\ be expected that the lignin would oe solubilized; hence the Kolbe reaction might function as an effective method for the delignification of wood. A series of spruce wood cooks with aqueous sodium bicarbonate and carbon dioxide under pressure were …  Read more

Le syndrôme Birt-Hogg-Dubé (BHD) est une maladie autosomale dominante héréditaire charactérisée par des troubles de la peau, des kystes pulmonaires, des pneumothorax spontanés et l'apparition de tumeurs rénales. Cette condition est causée par des mutations germinales dans le gène codant pour la protéine de 64 kDa nommée folliculine (FLCN). La protéine AMPK (AMP-activated protein kinase) est une clé de voute de l'homéostasie énergétique de la cellule. FLCN interagit avec AMPK par le biais de l'interaction avec les FNIP, les FLCN-interacting proteins. On ignore toujours le détail des fonctions moléculaires de FLCN, ainsi que de son impact sur le métabolisme cellulaire …  Read more

The first part of my work evaluates bilateral supramaximal transcutaneous phrenic nerve stimulation as a diagnostic test for respiratory muscle fatigue. I found that twitch transdiaphragmatic pressure (Pdi,T) was inversely and linearly related to lung volume (V$ sb{ rm L}$) both before and after fatigue. Although fatigue caused significant decrease in Pdi,T amplitude at all V$ sb{ rm L}$, the fractional decrease in Pdi,T was greater at high V$ sb{ rm L}$, indicating the importance of V$ sb{ rm L}$ as an independent variable that needs to be controlled whenever Pdi,T is determined. Twitch mouth pressure (Pm,T) was found to …  Read more

Nous avons étudié 42 cas de brachythérapie de cancer rectale avec protection incluse dans le traitement mais sans protection incluse dans la planification du traitement et calcul des distributions de doses. Pour étudier la distribution des doses dans les cas protégés, nous avons prélevé des informations importantes du système PLATO BPS et rétabli les plans de traitement PLATO avec des erreurs négligeables. Sur ces bases nous avons ensuite implémenté et validé les algorithmes de superposition des doses et appliqué ces algorithmes sur tous les patients, découvrant que bien que la dose pour tissu sain a été réduite, 10 des 42 …  Read more

Prior to 1979, the legal system of the People's Republic of China (PRC) did not provide any mechanism for foreign direct investment (FDI). China's decision to accept FDI came with the arrival of a new political leadership set upon the pursuit of radically different economic policies following the Cultural Revolution. The new leadership sought to take China on the quickest route to modernization while still remaining loyal to the socialist state. Therefore, while the Chinese Constitution insists on public ownership as the basis of the economy, it also recognizes and encourages other forms of economic activity which benefit the national …  Read more

Background: Frailty is a common comorbid condition in elderly patients with advanced chronic kidney disease (CKD). Despite a significant and increasing prevalence, there is a lack of interventions for this population, especially in those patients who are pre-dialysis. Objectives: The purpose of this study was to investigate the feasibility of prescribing a 12 week home based exercise intervention that combined aerobic and resistance components. Methodology: Five patients, aged ≥ 65 years were recruited for this study. Inclusion criteria required a glomerular filtration rate of ≤45 mL/min/1.73m2 and demonstrating 3 out the 5 frailty criteria, as defined by Fried. Patients completed …  Read more

La résistance aux antimicrobiens (RAM) des agents pathogènes d'origine alimentaire est une préoccupation constante et une menace sérieuse pour la santé publique. La résistance croissante rend le traitement clinique plus difficile à prendre en compte sur les manifestations indésirables de la santé et conduit à des périodes de récupération prolongées et à des taux de mortalité élevés. Par conséquent, un dispositif rapide, portable et facile à utiliser doit être développé pour la détection des bactéries RAM dans les produits alimentaires. Dans ce projet de thèse, une puce microfluidique hybride PDMS/papier basée sur une réaction colorimétrique a été développée pour effectuer …  Read more

Aminoglycosides are broad-spectrum antibiotics that target the A-site of bacterial 16S ribosomal RNA. Their use, however, is increasingly threatened by the rapid spread of resistance. One of the most common determinants of aminoglycoside resistance in bacteria is the expression of a class of enzymes known as aminoglycoside 6′-N-acetyltransferases (AAC(6′)s). These enzymes use acetylcoenzyme A (AcCoA) to acetylate most aminoglycosides at the 6′-NH2, thus decreasing their affinity for RNA and leading to bacterial resistance. One strategy pursued by the Auclair research group to overcome aminoglycoside resistance is to develop AAC(6′) inhibitors. Chapter 2 of this thesis describes enzymatic studies with the …  Read more

Receptor-interacting serine/threonine protein kinase 4 (RIPK4) and its kinase substrate the transcription factor interferon regulatory factor 6 (IRF6) play critical roles in the development and maintenance of the epidermis. In addition, it has been previously shown that RIPK4 is a NOTCH target gene that suppresses the development of cutaneous and head and neck squamous cell carcinomas (HNSCCs). In this study, autochthonous mouse models were used, where the expression of Pik3caH1047R oncogene predisposes the skin and oral cavity to tumor development and shows that not only loss of Ripk4, but also loss of its kinase substrate Irf6, triggers rapid SCC development. …  Read more

In recent years, investment arbitration tribunals are increasingly confronted with allegations of corruption, mostly invoked by host States as a defense to investors’ claims. After an affirmative finding of an alleged corrupt act between the investor and a public official of the host State in the establishment or conduct of the investment, tribunals have adopted a binary approach to the issue – if they uphold allegations of corruption, they completely dismiss the investor’s submissions. This binary approach has resulted in an asymmetry of liability for the two parties to a corrupt act (i.e., investors and host States/host State officials), failing …  Read more

AMPA receptors (AMPARs), a member of the ionotropic glutamate receptor (iGluRs) family, are responsible for mediating fast excitatory neurotransmission in the mammalian brain. Upon receiving information in the form of glutamate release from the presynaptic neuron, AMPARs rapidly open to briefly depolarize the postsynaptic neuron and then quickly deactivate, which effectively ensures precise and high-fidelity information transfer between neurons. Different neuronal cell types integrate this information differentially, and this process depend on the duration, amplitude and constituents of AMPAR-mediated currents. Hence, understanding the gating and permeation properties of AMPARs has long been a vehement area of research. Here, using a …  Read more

Studies for the Second Womb is a mixed piece written for tenor saxophone and violoncello with live electronics. As scientific research shows, fetuses can begin to hear sounds around 20 weeks of gestation. The conceptual idea behind this piece is to recreate the very first hearing experience of human beings, which happens inside a matrix, or more precisely the womb. To contrive this idea not only conceptually but also symbolically, some musical materials such as pitches are determined by chemical research on human amniotic fluid, via a self-made CAC (computer-assisted composition) Max patch to convert parameters from NMR spectroscopy to …  Read more

This dissertation consists of three essays: (I) Double Liability, Moral Hazard and Deposit Insurance Schemes, (II) Contract Costs, Lender Identity and Bank Loan Pricing, and (III) Bank Capital Structure and Differential Lending Behaviour. The first essay proposes to add double liability to a deposit insurance scheme to induce insurees (depository financial institutions) to reveal their true risk types. The second essay looks at the differential lending patterns of American banks versus Japanese banks. The third essay discusses the relationship between the characteristics of a lender and those of the borrower.  Read more

The use of wind turbines is an efficient and widespread means of obtaining natural wind energy. However, the increasing number of end-of-life wind turbine blades has already become a hidden danger worldwide. Traditional disposal routes can trigger many environmental, economic, legal, and other problematic aspects. A novel recycling approach, which is based on mechanical grinding and combined with 3D printing techniques, has enjoyed considerable success due to positive characteristics, such as non-environmental pollution, low cost, and excellent mechanical properties of the fabricated samples.Considering the material structure complexity of 3D printed material samples, the Representative Volume Element (RVE) stands out among …  Read more

Systems modelling nanoscale structures have been studied in the context of the theory of energy level statistics in the ballistic and mesoscopic as well as the insulating regimes. Statistics were obtained using a new unfolding scheme based on the existence of a local stationary property for fluctuations of the energy spectra. Two different models were used in the study with particular emphasis on the relevance to the physics of nanoscale devices. Thus, a quantum billiard model composed of a quasi-two-dimensional tight-binding atomic lattice was introduced. The results of the statistical analysis of the spectra of the models were compared throughout …  Read more

Les progrès de l'apprentissage automatique ont inspiré une nouvelle génération d'algorithmes pour la modélisation des structures biomoléculaires - des géométries non euclidiennes typiques qui font allusion à leurs fonctions telles qu'elles sont définies dans un vaste réseau intracellulaire d'interactome. Parmi eux, l'apprentissage d'une représentation distribuée significative de ces structures moléculaires s'est révélé prometteur pour répondre à des questions fondamentales en sciences de la vie, accélérer le processus de découverte de médicaments dans l'industrie, et bien d'autres. Cette thèse se concentre sur les ARN, une population diverse de macromolécules qui portent l'information génétique, et en se repliant sur eux-mêmes pour former …  Read more

Les cellules sont les unités de base de la vie, et pourtant, elles sont régies par de nombreux processus subcellulaires délicats et, dans une certaine mesure, fragiles, qui sont essentiels à leur survie. Une simple mutation génétique pourrait éventuellement obstruer des processus de régulation importants ou perturber le fonctionnement du produit qu’elle encode, ce qui pourrait éventuellement entraîner la disparition de l’ensemble du système. Par conséquent, il est important de mieux comprendre les nombreux processus de contrôle de la cellule et les facteurs de régulation qui leur sont associés, un exemple frappant étant le mécanisme lié à la localisation sous-cellulaire …  Read more

IGFBP-3 est la plus abondante des protéines de liaison qui transporte et contrôle la biodisponibilité et la demi-vie de l'IGF-1 et l'IGF-2. Dans cette étude, on s'est concentré sur la colite due au dextran de sulfate de sodium (DSS); une approche induite chimiquement à l'étude de la rectocolite hémorragique dans un modèle murin. Les dommages causés par le DSS affectent la paroi intestinale, ce qui entraîne par la suite une réponse inflammatoire dans les parties distales du côlon. Les dommages à la paroi intestinale peuvent être surmontés par la capacité des cellules épithéliales intestinales de réparer les dégâts grâce à …  Read more

In order to model the transport and fate of aniline and chloroaniline in the subsurface, the geochemical reactions between these contaminants and important metals and minerals surfaces must be quantified. The thermodynamic stabilities of the aqueous and surface aluminum-aniline and aluminum-2-chloroaniline complexes were investigated at 55$ sp circ$C and 80$ sp circ$C. Solubility and adsorption experiments place quantitative constraints on the thermodynamic properties of these complexes. No evidence was found for stable Al-aniline or Al-2-chloroaniline aqueous complexes. Conversely, the adsorption data provide unequivocal evidence for the presence of two distinct surface Al-aniline and A-chloroaniline complexes according to the following reactions: …  Read more

Le cancer de la prostate est le cancer le plus répandu chez les hommes canadiens et le troisième plus mortel au Canada. Bien que dans son état localisé, ce cancer peut être pris en charge cliniquement, certains patients atteindront les stades avancés de la maladie qui sont associés à un déclin de la qualité de vie et à des taux de mortalité élevés. Les options thérapeutiques du cancer de la prostate avancé ont considérablement évolué au cours de la dernière décennie. Cependant, les bénéfices incrémentaux sont faibles et sont associés à des coûts élevés, représentant des options peu coût-efficaces qui …  Read more

Le problème de la prescription de la mesure de courbure est l'un des problèmes les plus importants dans les domains de la géométrie différentielle et des équations aux derivées partielles. Dans cette thèse, nous étudions le problème de la prescription de la mesure de courbure sur l'espace hyperbolique. Nous établissons l'existence et la regularité des solutions de cette problème. La clé sont les estimations de la regularité C² des solutions des EDP complètement non linéaires correspondants au l'espace hyperbolique  Read more

Contexte: Un aperçu de la base neurale des processus de la hédonie provient d'études sur la palatabilité des aliments chez les rongeurs. Il a été démontré à plusieurs reprises que les manipulations pharmacologiques de la coque du noyau accumbens (NAcSh) augmentent la réactivité du goût hédonique, mais la contribution de composants spécifiques du circuit NAcSh est inconnue.Méthodes: Les manipulations optogénétiques bidirectionnelles sont ciblées sur les principaux neurones de projection NAcSh et les voies afférentes des souris pendant les tests d'alimentation libre. Le nombre de coups de langue par épisode de consommation est utilisé comme mesure de la palatabilité des aliments, …  Read more

Caulobacter crescentus has an asymmetric cell division program that yields distinct flagellated swarmer cell and a sessile stalked cell types. Chromosome replication is restricted to the stalked cells where it initiates exactly once per cell cycle. To better understand the DNA sequence requirements for chromosome replication, I systematically altered the cloned chromosome replication origin (Cori), and assayed these mutations in a Cori-plasmid context and in a whole chromosome context. Previous studies implicated the cell cycle transcription regulator (CtrA) in multiple cell cycle events. CtrA is also proposed to regulate chromosome replication by binding five sites (a-e) inside Cori. Altered CtrA …  Read more

Joyal, Jean-Sébastien (Supervisor2)  Read more

During the development of modern scientific soil mechanics, more attention was paid to the behaviour of clays than to other types of soil (Aylmore and Quirk, 1959; Norrish, 1954, among others). It has been pointed out that physico-chemical factors are important in the prediction of mechanical properties of such soi1s (Rosenqvist, 1962; Lambe, 1960). [...]  Read more

Illite crystallinity (IC), organic reflectance (R$ sb{ rm o}$) and fluid inclusion data reveal a southeastward increase of diagenetic and anchimetamorphic grades in the External Domain of the southern Canadian Appalachians. In the high grade diagenetic zone ($0.62 sp circ Delta 2 Theta le$ IC; R$ sb{ rm o}$ $ le$ 2.6%), hydrocarbons are the dominant fluids with a mean homogenization temperature (T$ sb{ rm b}$) of 110$ sp circ$C. In the highest-grade diagenetic zone (0.42$ sp circ Delta 2 Theta$ $ le$ IC $< 0.62 sp circ Delta 2 Theta$; 2.6% $<$ R$ sb{ rm o} le$ 3.7%), methane …  Read more

Hess, Robert F. (Supervisor2)  Read more

La fatigue musculaire est un facteur de risque important de troubles musculo-squelettiques. Cependant, les mécanismes d'adaptation de la fatigue aux mouvements répétitifs des membres supérieurs restent flous. Notamment, la question de savoir si l’emplacement de la fatigue, le sexe et la posture de travail affectent les adaptations cinématiques à la fatigue demeure pourtant un sujet confus. L'objectif de cette thèse était d'examiner les effets spécifiques au sexe par rapport aux différents types de fatigue sur les caractéristiques cinématiques d'une tâche répétitive du membre supérieur.De jeunes adultes en bonne santé, hommes et femmes, ont été recrutés pour trois expériences distinctes qui …  Read more

The primary objective of this research project is to develop a system for precision spraying of herbicides in a corn field. Ultimately, such a system would permit real-time image collection, processing, weed identification, mapping of weed density and sprayer control using a tractor-mounted digital camera and on-board computer. The initial hypotheses underlying this project were (1) that it is possible to train an artificial neural network (ANN) to distinguish weeds from a crop species (corn in this study); (2) that it is possible to differentiate between weed species; and (3) that precision spraying can significantly reduce the quantity of herbicide …  Read more

Ce projet de recherche a pour but l'utilisation d'un réseau neuronal artificiel RNA afin de simuler et prédire les variations de la hauteur de nappe libre pour des systèmes de gestion différents, tels le drainage conventionnel de même que l'irrigation souterraine. Les données de bases sont les facteurs météorologiques, tels, precipitation, évapotranspiration et hauteur moyenne de la nappe libre. Les données de precipitation et d'évapotranspiration recueillies ont été utilisées afin d'obtenir les predictions d'un modèle informatique éprouvé connu sous le nom de DRAINMOD. Les résultats ainsi obtenus ont été utilises pour développer un modèle base sur les RNA. Les résultats …  Read more