McGill University Thèses et mémoires par auteur commençant par A

Background: Annually, oral cancer is responsible for more than 177,000 deaths worldwide. Squamous cell carcinomas constitute the majority of these cancers that initially begin as benign oral lesions that later undergo malignant transformation. Delay in diagnosis is a major contributing factor to the advanced stage at diagnosis and subsequently poor prognosis of oral cancer. Diagnosis of oral lesions at an early stage remains challenging for many clinicians. While diagnostic algorithms have been proposed in the literature to assist with clinical diagnosis and minimize delay, there is a dearth of comprehensive evidence synthesis and a discussion on their clinical and pedagogical …  Read more

Notwithstanding the innovative changes in biotechnology, medical devices and other therapeutics, errors in medicine continue to cause harm to patients. Current definitions of medical error do not reflect the full reality of error causation. Medical error taxonomy is narrowly focused on system weaknesses in health institutions and human error. System weaknesses in licensing and monitoring organizations, health care suppliers, health profession self-regulation and government regulating organizations, conduct by leading health professionals and medical research industry risks, all lead to significant harm that is not recognized in medical error accountability. These players do not fulfill their mandates. Evidence demonstrates negligence, incompetence, …  Read more

Floating Offshore Wind Turbines (FOWTs) are a promising technology to harness the abundant offshore wind energy resources in open ocean areas. A FOWT consists of a floating platform, the moorings, and the wind turbine structure (tower + Rotor-Nacelle Assembly (RNA)). The main focus of this thesis is to develop multibody dynamic models that integrate the structural dynamics, and hydrostatic, hydrodynamic, aerodynamic and mooring system loads. Special efforts are also devoted to characterize the mooring and hydrostatic loads as main sources of systems stiffness that shapes the dynamic behavior of the system. Two approaches for modeling the platform/tower dynamics are developed, …  Read more

Nicolau, Belinda Farias (Supervisor2)  Read more

Experiments were carried out in order to investigate the response of reinforced concrete bridge pier caps. The six specimens were tested in order to study the influence of the geometry of the pier caps, the amount and distribution of uniformly distributed reinforcement in the pier caps and the details of anchorage of the reinforcement. The experimental results were compared with predictions using plane sections analyses, simple strut and tie models, the PCI design method, more refined strut and tie models and non-linear finite element analyses using program FIELDS.  Read more

Zilic, Zeljko (Supervisor1)  Read more

Nicolau, Belinda Farias (Supervisor1)  Read more

Soybean [Glycine max (L.) Merr.] seeds contain isoflavones that have positive impacts on human health. Field and greenhouse experiments were conducted in Quebec Canada to determine the effects of management and environmental factors [seeding date (late May and mid June), row spacing (20-, 40- and 60-cm), weeds (presence or absence), irrigation levels (low, moderate, and high) and genotypes (Proteina, Orford, and Golden)] and of foliar applications of elicitor compounds (i.e., LCOs, chitosan, and actinomycetes spores), on the isoflavone concentrations of mature soybean seeds, and other important seed characteristics. Our results indicated that environmental and agronomical factors have a great impact …  Read more

In an attempt to investigate the cause of change in the competitive ability between monocots and dicots in a pastureland in Farnham, Quebec under CO2 enrichment, I chose to study the response of Plantago major (dicot) and Poa pratensis (monocot) grown in ambient and elevated CO2 chambers, hypothesizing that a large increase in root biomass of dicots would be observed under elevated CO 2. A transient stimulation of root biomass of Plantago major was found during the first month of CO2 exposure but disappeared later. The second objective of this study was to examine the effect of 5 years of …  Read more

Marino, Faleh Tamimi (Supervisor2)  Read more

Task uncertainty and noise---generically referred to as uncertainties in the thesis---in the design and operation of robotic mechanical systems pose a major challenge to the designer. The aim of this thesis is to contribute to the laying down of the foundations on which the design of robotic mechanical systems, in the presence of uncertainties, is to be based. Uncertainties are accounted for by means of robustness. To this end, a theoretical framework as well as a general methodology for model-based robust design are proposed. Within this framework, all quantities involved in a design task are classified into three sets: the …  Read more

Amidst the global spread of COVID-19, prevention measures forced school closures causing a shift to virtual learning. Educators worldwide were forced to adapt to new teaching methodologies without sufficient guidance, training, or resources. Overall, this pandemic has highlighted the essential role of teachers; however, the lack of research done on their experiences with remote education has left little guidance for educators worldwide. Eight high school instructors, four in Montreal, Canada, and four in Zarqa, Jordan, were interviewed in this study to explore their experience with the transition to remote education during the COVID-19 pandemic. More specifically, teachers were asked to …  Read more

The absorption of hydrogen sulfide and carbon dioxide in aqueous sodium carbonate solution was studied on a pilot scale packed column operated counter-currently under atmospheric pressure. The absorption column was 7.5 cm in diameter and 150 cm in height and packed randomly with 6 mm Intalox Saddles. It was designed to remove hydrogen sulfide from a gas mixture of 1.5% hydrogen sulfide and 15% carbon dioxide at an efficiency of 95%. Reliability of the experimental setup has been perused by investigating the residence time distribution of the gas phase in the column and by studying the absorption of carbon dioxide …  Read more

Kubes, G. (Supervisor)  Read more

Energy modulated electron therapy (EMET) is a promising treatment modality that has the fundamental capabilities to enhance the treatment planning and delivery of superficially located targets. Although it offers advantages over x-ray intensity modulated radiation therapy (IMRT), EMET has not been widely implemented to the same level of accuracy, automation, and clinical routine as its x-ray counterpart. This lack of implementation is attributed to the absence of a remotely automated beam shaping system as well as the deficiency in dosimetric accuracy of clinical electron pencil beam algorithms in the presence of beam modifiers and tissue heterogeneities. In this study, we …  Read more

Current dose photon calculation algorithms have shortcomings in calculating dose distributions accurately in complex, heterogeneous phantoms. In this work, using existing Monte Carlo (MC) algorithms, we implemented and validated a comprehensive MC treatment planning system (MCTPS). We compared MCTPS with the corrected pencil beam algorithm used in the commercial TPS, CadPlan (V2.7.3). The accuracy of dose distributions calculated by MCTPS was studied for six lung cancer patients in two modes: without correction for inhomogeneity (the clinically used method) and with the equivalent tissue air ratio (EgTAR) inhomogeneity correction switched on. Without the use of inhomogeneity corrections, absorbed dose estimated by …  Read more

This dissertation examines the relationship between religion and state in Saudi Arabia. More than any other country in the Muslim world, Saudi Arabia is identified with Islam. It is the state religion, its source of political legitimacy, it shapes state policies and activities, and serves as the moral code of society. The findings of this study support the hypothesis that the state, because of its monopoly of force and resources, and the need to maintain autonomy, can not tolerate an autonomous religious domain that would compete with it for the loyalty of citizens. The state will extend its authority to …  Read more

Salmonella enteritidis has recently emerged as a potential pathogen in poultry products. The growth of S. enteritidis in poultry is affected by several factors such as storage temperature, pH, water activity, modified atmosphere and the presence of preservatives. All of these factors may act alone or in combination with each other resulting in a synergistic, antimicrobial effect. In this research, initial storage studies were done to determine the effect of various atmospheres (air, vacuum, oxygen absorbent and gas packaging) on the microbial changes of packaged chicken thighs followed by challenge studies with a strain of S. enteritidis$ sp{ rm{NAST}}$. Chicken …  Read more

A total of twenty-eight Bacillus spp. isolated from value-added surimi nuggets and their raw ingredients, were tested against each other and selected reference strains of Bacillus and Clostridium for their production of inhibitory substances using the deferred antagonism assay plating method. The isolated Bacillus strains showed inhibitory activity against all Bacillus strains, with the exception of the producer strain, as well as being effective against various strains of C. botulinum (type A, B and E). Subsequent studies showed that the inhibitory activity was detected in the culture supernatant in the late stationary phase of growth prior to sporulation. The inhibitory …  Read more

Maestro, Rolando Fausto Del (Internal/Cosupervisor2)  Read more

Introduction: La chirurgie pour un cancer du colon est associée à un taux élevé de morbidité, particulièrement chez les personnes âgées. Il y a présentement un manque d'outils d'évaluation pour les patients vulnérables à risque de complications postopératoires. Le but de cette étude était d'identifier des prédicteurs de complications postopératoires graves chez les personnes âgées subissant une chirurgie pour cancer du colon, basé sur des données provenant de statistiques récentes sur l'utilisation des services de santé.Méthodes: Une cohorte prospective historique de patients atteints de cancer du colon âgés de 65 ans ou plus a été assemblée à partir de données …  Read more

Material characterization is a very important tool needed to describe and enhance material mechanical properties and to develop optimum material chemistries and microstructures. The usual approach of achieving the above using extensive experimental methods has been shown to be expensive and time consuming. This led to the development of the micro mechanical modeling, which can be used to predict the material behavior without the need for the extensive experimental investigation and is based on microstructural characteristics of the material. In this work, a micro mechanical model is developed to predict the mechanical properties of dual phase steels consisting of martensite …  Read more

Le cancer colorectal (CCR) est la deuxième cause la plus importante de mortalité dérivée du cancer en Amérique du Nord. La mort causée par le CCR peut être attribuée à la métastase du cancer. Le site le plus fréquent de métastase éloignée de l'origine du CCR est le foie. Si cela est possible, la chirurgie donne la seule occasion de traitement pour les patients avec des métastases hépatiques du cancer colorectal (MHCCR). Les soins administrés après résection ainsi que le choix de chimiothérapie adjuvante dépendent de l'évaluation pathologique du grade de la tumeur. Plusieurs méthodes d'évaluation histopathologique ont été dévelopées, …  Read more

Regrowth in the lesioned central nervous system is impeded by inhibitory molecules including myelin-associated inhibitors (MAIs) and chondroitin sulfate proteoglycans (CSPGs). Inhibitory molecules engage neuronal cell surface receptors and activate the small GTPase RhoA in injured neurons to mediate neurite outgrowth inhibition through targeted modifications to the cytoskeleton. Inhibition of RhoA with the ribosyltransferase C3 attenuates neurite outgrowth inhibition in vitro and in vivo but the ubiquitous expression and multifunctionality of RhoA may limit the specificity of therapeutic RhoA antagonists. The hypothesis of the thesis is that molecules that functionally interact with RhoA to mediate myelin-dependent inhibition may represent more …  Read more

Intervertebral disc degeneration (IVDD) is driven by chronic inflammation, extracellular matrix degradation, and cytokine–neurotrophin interactions that promote hyperinnervation and persistent pain. Current therapies remain primarily palliative, while surgical procedures such as discectomy and spinal fusion alter spinal mechanics and accelerate adjacent-level degeneration, offering only temporary relief. Existing pharmacologic candidates under evaluation typically act on a single aspect of degeneration, either suppressing inflammation or supporting matrix repair. Since ECM degradation and inflammation reinforce one another throughout IVDD progression, an effective therapeutic approach must address both structural deterioration and inflammatory signalling rather than targeting either pathway alone.Link N (LN) and its derivative, …  Read more

As the level of realism required by modern video games and movies increases, so does the need for natural-looking simulations. Reproducing the physical behaviour of humans has been one of the pillars of modern research in the field of computer animation. This is a challenging problem because it is difficult to describe what constitutes a natural pose or motion. This problem can be addressed through optimizations that build on assumptions and approximations about properties such as energy, head orientation, or centre of mass position. Alternatively, instead of attempting to create realistic models for humans, motion capture can be used to …  Read more

Abstract Variability in seasonal precipitation, potential climate change impacts, competition for water among users, rising population and increasing food demands are putting pressure on agricultural water demands. For irrigated agriculture in Canada to play a major role in addressing current and future global food supply problems, more innovative and sustainable irrigation management approaches are required. In this context a decision support system that ensured more effective irrigation water allocation, application and optimisation was developed. Crop water requirements and irrigation schedules for bell pepper (Capsicum annuum L.) were obtained from greenhouse and field studies. Greenhouse experiments were conducted to determine appropriate …  Read more

My thesis consists of two essays on the affective influences of attitude importance and product involvement on judgment and choice. The first essay examines the role of attitude importance in judgment formation. For example, consider the ease-of-retrieval phenomenon, a typical finding on metacognitive effects in judgments: consumers who are asked to think of many reasons in favor of a product (which is difficult) tend to like the product less than those who are asked to think of only a few reasons (which is easy), showing that the experienced metacognitive difficulty during the reason-generation process affects the evaluation of a product …  Read more

Cellular perturbations cause the proteins to misfold precluding their functions. In response to proteotoxic stress, cells downregulate gene expression by reducing cap-dependent translation. Concurrently, they upregulate the expression of a subset of molecular chaperones known as Heat Shock Proteins (HSPs) in charge of protein folding. The fast induction and rapid attenuation of the inducible HSP70 expression define the Heat Shock Response (HSR), which is critical for cell survival from stress. However, the ubiquitous expression of the inducible HSP70 is toxic and promotes tumorigenesis in mammalian cells. Thus, the fast degradation of the HSP70 mRNA allows for tailoring the HSP70 synthesis …  Read more

Removable partial dentures (RPDs) provide cost-effective treatment for millions of partially edentulous patients worldwide. However, RPDs often present several complications that result in treatment failure and patient dissatisfaction. The main reasons for these problems are the inadequate quality of the RPD framework and the lack of precise guidelines for designing retentive RPDs. We hypothesized that laser sintering/melting technology and advanced algorithms can improve the quality and design of removable partial denture treatments. Accordingly, the aim of this thesis is to optimize the quality and the design of removable partial dentures by using digital technology. Removable partial dentures (RPDs) are traditionally …  Read more

Cerruti, Marta (Internal/Cosupervisor2)  Read more

For the past few decades, analog voiceband modems have been used extensively to carry digital information over the Public Switched Telephone Network (PSTN). Conventional voiceband modems treat the PSTN as an analog communication channel. However, today's PSTN is mostly a digital network except for the basic telephone services provided via analog subscriber lines. The conventional model of analog voiceband channels is no longer adequate to characterize the physical connection between terminals with direct digital access to the network and voiceband modems connected to analog subscriber lines. Such a connection requires a different model in each direction. There are now international …  Read more

Ma, B. (Supervisor)  Read more

Kiss, Robert (Internal/Supervisor)  Read more

Shih, I.  Read more

This thesis gives an account of conflicts around corn agriculture by exposing the discrepancies between the extractive industry of monoculture and community-based alternative practices. In the context of the Anthropocene, this epitomizes a broader tension between the impetus to claim accountability to the climate crisis and the incentive to reimagine new modes of relations with nonhumans. This thesis asks: how do plants and humans meet? By taking a new materialist standpoint, it further inquires: how do diverging practices of more-than-human relationality come to produce ecologies governed by distinct affects, ethics, and politics? This thesis opens with a literature review of …  Read more

As people continue to immigrate to Canada, it is becoming more important to consider the many social challenges that migrant youth face upon their arrival. The purpose of this MSW thesis was to evaluate the subjective experience of adolescents in a welcoming class who participated in a video art pilot project. Twelve adolescents were interviewed using a semi-structured qualitative format after the end of the project. They reported enjoying the group work process, discovering each other's talents and learning new skills such as how to use a video camera. All of these responses echo the goals of the Positive Youth …  Read more

Le contrôle de la corrosion des métaux est d'une importance technique, économique et environnemental. L'un des moyens les plus efficaces, pratiques et économiques pour la prévention de la corrosion des métaux impliques l'utilisation d'inhibiteurs de corrosion. Les inhibiteurs de corrosion jouent souvent un rôle important dans les systèmes de traitement de l'eau, fabrication de produits chimiques, l'industrie lourde, l'exploration et la production pétrolière et gazière, le raffinage du pétrole, et les industries de transformation où ils ont toujours été considérés comme la première ligne de défense contre la corrosion. Les inhibiteurs de corrosion interfèrent avec le mécanisme de corrosion afin …  Read more

Consider L to be a graded free Lie algebra over a principal ideal domain, and r a nonzero element of L such that its leading term s, i.e. its homogeneous component of highest order, is not a proper multiple. The main result we show in this thesis is that the graded ideal of leading terms of elements in R = (r) is equal to the ideal generated by the element s. As a consequence we prove that the center of L/R is trivial if the rank of the free Lie algebra L is greater than two.  Read more

We study quasi superharmonic functions in Brelot spaces and the relationship between a reduced function, and harmonic and Jensen measures. We introduce the concept of quasi multiply superharmonic functions on a product of two Brelot spaces and study their properties. A main result obtained is characterizing the quasi superharmonic functions in terms of harmonic, finely harmonic and Jensen measures. Then we prove that a quasi multiply superharmonic function on a product of Brelot spaces equals its lower semicontinuous regularization out side of a 2-negligible set. Further we give a sufficient condition on a Brelot space O under which O becomes …  Read more

Lachapelle, Kevin J (Supervisor1)  Read more

JUUL est une marque de cigarette électronique populaire auprès des fumeurs et de ceux qui n’ont jamais fumé, y compris les adolescents. Malgré l’utilisation généralisée de JUUL et les effets cardiovasculaires négatifs anticipés de la nicotine, aucune donnée n’existe sur l’impact du vapotage JUUL sur le développement de l’athérosclérose. L’objectif de cette étude était d’évaluer si l’exposition aux aérosols de cigarettes électroniques JUUL induitdes altérations pro-athérogènes précoces dans de jeunes modèles athérosclérotiques murins. Pour ce faire, les effets du vapotage d’aérosols JUUL aromatisés à la mangue ont été comparés à l’air ambiant et au véhicule (polyéthylène glycol: glycérine végétale; PG/VG) …  Read more

Subduction zones are where the largest earthquakes occur. In recent decades, scientists have also discovered the presence of episodic aseismic slip, including slow slip events (SSE), along most of the subduction zones. However, it is still unclear how these SSEs can influence megathrust ruptures. The Costa Rica subduction zone is a particularly interesting area as a SSE was recorded 6 months before the 2012 Mw7.6 earthquake, in the Nicoya Peninsula, suggesting potential stress transfer from the SSE to the earthquake slip zone. SSEs beneath the Nicoya Peninsula have also been recorded both updip and downdip of the seismogenic zone, making …  Read more

Urban transportation is a major contributor to greenhouse gas (GHG) emissions and air pollution. Worldwide, planners and policy makers are consistently encouraging individuals to reduce their reliance on private vehicles while promoting the use of public transit. While transit buses reduce per-passenger emissions of GHG and air pollutants, they generate a large amount of emissions on a vehicle basis especially when they are fuelled by conventional diesel. This research was motivated by the importance of reducing transit bus emissions which can only be achieved after understanding the factors affecting transit bus emissions and exploring the effects of various emission reduction …  Read more