McGill University Thèses et mémoires publiés en 2020

Amin, Andalib, (Supervisor2)  Read more

The deformation of sea ice in the Arctic Ocean occurs along well-defined linear kinematic features, where shear and divergence form regions of open water (leads) and ice ridges. The presence of leads and ridges in the ice cover impacts ocean-atmosphere moisture and heat fluxes, as well as salt/freshwater fluxes in the surface ocean as ice forms or melts in the winter and summer, respectively. A realistic representation of sea-ice deformations by sea-ice models is therefore essential to adequately model the Arctic climate system. The goal of this thesis is to evaluate the ability of different sea-ice rheological models to simulate …  Read more

Mussbacher, Gunter (Supervisor1)  Read more

Variable selection is one of the most important tasks in statistical analysis. It helps provide researcherswith more interpretable and parsimonious models. For variable selection procedures, the capability ofcontrolling the false discovery rate (FDR) is very important in the post selection inference phase of theresearch. This topic was intensively studied in the past with different approaches to achieve an optimalsolution, and recently a new family of methods emerged named "Knockoffs Filters" (Barber and Candes(2015), Candes et al. (2017), Sesia et al. (2017), Romano et al. (2019)). The knockoffs method enjoyssome desired properties namely: It does not restrict the model relating the …  Read more

T cells defend their hosts by scanning other cells for ligands from potentially pathogenic sources. Upon antigen detection, they produce and consume extracellular proteins called cytokines to communicate with each other. Those messenger proteins play a fundamental role in scaling the nonlinear, out-of-equilibrium immune response. Yet, no quantitative theory exists to systematically account for the dynamics of multiple cytokines at once. However, state-of-the-art experimental data from our collaborators (Altan-Bonnet lab, NIH) reveal that cytokine concentrations encode information about the strength, or quality, of the ligands detected by the T cells. In this thesis, we combine cytokine biology, information theory, and …  Read more

AbstractThis qualitative self-study explores the relationship between the personal and professional dimensions of a teacher’s life that shape identity and praxis. The question driving the research is: How have my life experiences (personal and professional) contributed, or not, to my identity as a high school teacher over the past 40 years? The two sub-questions were: What kinds of life experiences emerge in my recollection process? How do others perceive me as a teacher? I have written a memoir revealing my experiences as a woman, daughter, student, teacher, wife, and mother over six decades, and the role that perceptions of me …  Read more

Tremblay, Bruno (Supervisor1)  Read more

L-3,4-dihydroxyphenylalanine (L-DOPA) remains the most effective treatment for Parkinson’s disease (PD). However, chronic administration of L-DOPA leads to the emergence of motor complications such as dyskinesia in the vast majority of patients. Serotonin 2A (5-HT2A) receptor blockade is a validated approach to alleviate dyskinesia, but its effectiveness appears to be of limited magnitude. Recently, we have demonstrated that activation of metabotropic glutamate 2 (mGlu2) receptors reduce dyskinesia in the 6-hydroxydopamine (6-OHDA)-lesioned rat. Based on the fact that 5-HT2A and mGlu2 receptors form a functional hetero-complex, we hypothesised that combining EMD-281,014, the most selective 5-HT2A antagonist commercially available with LY-354,740, a …  Read more

Douglas, Peter (Supervisor1)  Read more

Human-induced climate change is one of the biggest threats facing human-kind and the global environment today. Climate action plans at the global, regional, and local scales set C neutrality (a state of no net increase in atmospheric C achieved by balancing emissions and sequestration) as a key climate change mitigation target. Action plans to achieve C neutrality often focus on emissions reduction, with limited focus on quantifying, measuring, and increasing C sequestration. Certain forms of C sequestration include afforestation, which can remove existing C trapped in the atmosphere through photosynthesis in a cost-effective way, while also providing additional ecosystem services, …  Read more

L'intérêt, les résultats et la motivation des élèves pour les sciences diminuent à mesure qu'ils atteignent l'école secondaire. Il en résulte une diminution du nombre d'étudiants qui poursuivent leurs études et, par la suite, leur carrière dans les domaines des sciences, de la technologie, de l'ingénierie et des mathématiques (STIM). Étant donné l'importance des STIM dans une société prospère, il est utile de se pencher sur la manière d'accroître l'intérêt, les résultats et la motivation des étudiants dans le domaine des sciences. L'un des moyens d'y parvenir est d'accroître la curiosité des élèves dans les cours de sciences. Afin d'étudier …  Read more

Genome integrity is critical for homeostasis, with systems in place to detect and repair DNA damage, collectively termed the DNA Damage Response (DDR). Defect in any of these systems may lead to cancer progression and neurological disease via resultant genome instability. Our lab recently showed a link between DDR signaling and RNA trafficking, defining a damage-induced messenger RNA (mRNA) nuclear retention mechanism which eliminates defective cells during embryogenesis in Drosophila. For this project we assessed how DDR signaling impacts post-transcriptional gene regulation, particularly through differential subcellular distribution and function of RNA molecules and RNA binding proteins (RBPs) in human cells. …  Read more

In this thesis, we review the classical theory of Stokes phenomenon, and its extension to unfoldings of irregular singularities following the work of J. Hurtubise and C. Rousseau. We then consider the approach to classification of singular systems using groupoids, presented by M. Gualtieri, S. Li, and B. Pym, and how this extends to unfoldings. In particular, we introduce the unfolded twisted pair groupoid, which serves as the universal domain of definition for generic analytic unfoldings of linear differential systems with an irregular singularity at the origin  Read more

Dans les cas de paralysie cérébrale (PC), le dépistage et l'intervention précoces sont considérées comme étant des pratiques exemplaires. Les études effectuées à ce jour se sont concentrées principalement sur des enfants qui présentent un risque élevé de PC. Les praticiens de première ligne n'ont pas accès à des outils spécifiques pour la PC qu'ils puissent efficacement appliquer dans leur contexte. Il est essentiel que tout retard inutile soit évité. L'objectif global de ce projet est de créer le contenu nécessaire pour élaborer des outils d'application des connaissances (AC) conviviaux pour les praticiens de première ligne pédiatriques. Les objectifs spécifiques: …  Read more

The needs for movement and for sleep are often considered key components of welfare, with severe or prolonged deprivation in one or both likely to have lasting impacts on health and well-being. Environments are often described as central elements defining the capacity of individuals to fulfill these needs, and dairy cows are no exception: unfortunately, common housing systems used nowadays generally restrict the opportunities of movement and the capacity to rest of dairy cows. While tie-stall systems are deemed the most restrictive of all, in general, the presence of stalls in the environment of cows has been associated with altered …  Read more

Cardiovascular disease is the second leading cause of death in Canada, resulting in $20.9 billion annual healthcare expenditures. Understanding the mechanics of the human aorta is fundamental for studying pathology progression and improving surgical grafts. This work is an experimental evaluation of the dynamic response of the human descending thoracic aorta to pulsatile flow, for hyperelastic and viscoelastic material characterizations. A mock circulatory loop was built to reproduce physiological cardiac pulsatile conditions for the aorta ex-vivo, and obtain the viscoelastic parameters with fluid-structure interactions. Then, specimens were dissected into the three constituent layers: intima, media and adventitia, for layer-specific material …  Read more

The retinoblastoma tumour suppressor protein (pRB) and E2F transcription factors are vital regulators of the cell cycle. There are three pRB and eight E2F family members in mammals, which play overlapping and distinct roles in development and disease. Notably, loss of pRB and deregulated E2F are hallmarks of cancer cells. Studies largely performed using tissue culture cells led to the classic model of E2F as an inducer of S-phase genes to promote cell cycle induction. However, in vivo studies have been revealing much more complex roles for E2F that remain poorly understood. To address this, I examined the regulation and …  Read more

This dissertation analyzes international law, the International Court of Justice (ICJ) and indigenous territorial claims from the perspective of legal geography, a field of study that investigates the mutually constitutive relationship between law, space and power in society. I use the term “international law-spacetime-justice nexus” to signify that the analysis is concerned with the spatiotemporal foundations of international law and their relationship with concepts of international political justice. The dissertation analyzes matters pertaining to the spatial and structural (in)justices associated with the international legal principle of uti possidetis, a doctrine that holds that decolonizing or seceding states are entitled to …  Read more

Medical image guidance for pedicle screw implantation during spinal fusion reduces the complication rate for patients drastically. Preoperative images require image-to-patient registration to provide accurate information and afterwards, accurate guidance. Automatic registration based on tracked intraoperative ultrasound is a promising method but requires a robust and accurate algorithm. This thesis presents the comparison of three different algorithms that could potentially satisfy all clinical requirements in terms of image-to-patient registration: the Iterative Closest Point algorithm, a more robust variant of ICP and the Coherence Point Drift (CPD) algorithm.The accuracy, precision, speed, robustness regarding initial misalignment, and robustness regarding noise were evaluated …  Read more

Les cellules des organismes vivants interagissent de différentes manières, notamment par le biais de signaux biochimiques et mécaniques. Les métastases du cancer, la cicatrisation des plaies et le développement embryonnaire sont tous des exemples de processus multicellulaires desquels le comportement collectif de cellules émerge, en partie grâce aux interactions physiques entre cellules individuelles. L’étude expérimentale de telles interactions in vivo et in vitro est inestimable. Néanmoins, il n'est souvent pas possible de faire varier indépendamment des propriétés physiques spécifiques des cellules sans modifier d'autres aspects de leur comportement.Dans la présente thèse, nous développons deux méthodes pour simuler numériquement les interactions …  Read more

Our goal is to make progress towards learning auctions from limited access to value distributions. Towards this, we know that VC dimension cannot be used to efficiently obtain the uniform convergence property with respect to the empirical distribution. We show that in fact a more rened tool, the Rademacher Complexity, also requires an exponential number of sample points in the dimension to satisfy uniform convergence. However, given access to approximations of the true value distributions, we show in different settings how to construct auctions that are oblivious to the true distribution, yet yield close to optimal revenue  Read more

Objective: This thesis aims to explore the role of sex differences in characterizing verbal memory deficits in individuals experiencing a first episode of psychosis (FEP). In the healthy population, males tend to perform more poorly than females on verbal memory tests. Sex differences in the healthy population have implications for understanding cognitive and anatomical abnormalities in psychosis, especially given the propensity for greater illness severity among male patients. Thus, study one explored sex effects on verbal memory and their relation to functional outcome; and study two explored possible neuroanatomical correlates underlying this effect. Methods: In both studies, patients were treated …  Read more

This thesis analyzes the relationship between the exclusivity clauses of the Warsaw and the Montreal Conventions (Warsaw Regime), and the impossibility that these clauses posse upon States to simultaneously comply with some primary obligations under International Human Rights Law (IHRL). A detailed analysis of the core obligations of the IHRL regime would require a research beyond this master thesis; thus, I decided to limit the scope of this research to obligations under two key IHRL treaties: the International Convention on the Elimination of all Forms of Racial Discrimination (CERD) and the Convention on the Rights of Persons with Disabilities (CRPD). …  Read more

Organic and medicinal chemistry research contribute extensively to the discovery, optimization, and ton-scale production of numerous small molecules, such as novel drugs that treat life-threatening diseases. This research can be put in the context of the COVID-19 global pandemic, which has claimed many lives, shut down the entire planet, and made humanity reliant on chemistry (amongst which organic and medicinal chemistry play a key role) and biochemistry research to come up with innovative solutions in a short amount of time. A major hurdle in organic and medicinal chemistry research is the production of these complex life-saving small molecules and the …  Read more

The epidemiology of Listeria monocytogenes reveals that lineages I and II are more adapted for establishing successful mammalian infections, when compared to lineages III and IV. However, no genetic factor has been identified that comprehensively explains this variable. PrfA is the master regulator of virulence in L. monocytogenes and is indispensable during the cellular phase of infection. The mechanisms by which PrfA regulate intracellular virulence are well-understood, however, almost all experiments used to elucidate these mechanisms were performed using lineages I and II-derived isoforms of PrfA (PrfA_I/II). The current literature makes no distinction among the PrfA variants that have been …  Read more

Engert, James (Supervisor1)  Read more

La wollastonite est un silicate de calcium utilisé dans diverses applications industrielles telles que la production des céramiques, des plastiques, d’isolants thermiques, des produits pharmaceutiques et papier. La flottation de minerais de wollastonite contient des minéraux silicatés comme gangue, tel que le feldspath, le diopside et le quartz présentent de nombreuses difficultés et n’est que rarement traitée dans la littérature.Dans cette étude ont été employés des tests de microflottation, des mesures de potentiel zéta, de la spectrométrie photoélectronique X (SPX), de la spectroscopie ultraviolet-visible (UV-vis) ainsi que des tests d’adhésion bulle-particule, afin d’évaluer les interactions de la wollastonite, du quartz …  Read more

Les quelques dernières décennies ont apporté d’énormes progrès quant à notre compréhension sur la régulation centrale de l’équilibre énergique au niveau moléculaire ; cependant, des changements structurels au niveau cellulaire ou du circuit neuronal en tant que contributeur à une altération du poids n’a reçu que brève attention. D’autre part, certaines études antérieures qui attestent que des altérations structurelles au niveau de processus neuronaux ont lieu en réponse à des changements de régimes alimentaires sont basées uniquement sur un résultat de groupe dont les animaux n’ont été examinés qu’une seule fois ; l’aspect dynamique de ces changements reste donc irrésolu. …  Read more

Recent evidence supports the notion that both paternal and maternal mental health play a role in shaping the developmental trajectory of the child. While the adverse effects of maternal depression and anxiety on the child are well-documented, the role of the father requires further investigation. It is unclear, for example, whether or not the impact of paternal mental health varies depending on symptom type, level of severity, or timing with regards to the child’s developmental stage. Detailed characterization of paternal mental health factors may be particularly critical during middle childhood (6-8 years old), when the child needs to develop a …  Read more

Fong, Grace S. (Supervisor2)  Read more

Célébrité culturelle et diplomate, Pablo Neruda a visité la Chine deux fois dans les années 1950. Parmi les personnes qu’il a accueilies en Chine, Ai Qing, le poète acclamé du peuple, est rapidement devenu un ami avec Neruda. Centrée sur leurs rencontres dans les années 50, cette thèse prend comme point de depart les identités d’artiste et de politician de Neruda et d’Ai Qing, et soutient que la rencontre d’Ai Qing avec Neruda éclaire l’hétérogénéité de la création poétique d’Ai pendant une époque de crise nationale et de bouleversement sociaux. Enquêtant sur les conditions historiques qui ont rendu posible leur …  Read more

Shrier, Alvin (Supervisor1)  Read more

Dans la conception des éléments en béton armé ou précontraint, les éléments peuvent être subdivisés en deux types de régions : perturbées ou flexion. Les régions perturbées sont celles dans lesquelles l’hypothèse de Bernoulli ne pourra plus être appliquée puisque les sections planes ne restent pas planes après flexion. Dans ces régions, le flux des contraintes est perturbé à cause de la présence des discontinuités statiques (ex. la présence d’une charge concentrée) ou géométrique (ex. un changement brusque de la section transversale). Pour cette raison, une approche de conception régionale doit être suivie au lieu d’une approche en section. Le …  Read more

More studies are required in order to understand the molecular mechanisms that regulate the adaptations of arctic plants to extreme environments. The genus Oxytropis (Fabaceae) has been previously proposed as a source to investigate adaptation to extreme environments, and relevant evidence has already been found. Due to very slow growth rates of Oxytropis plants, limitations exist that prevent handling of the plants for research purposes. Therefore, the model plant Lotus japonicus (Fabaceae) has been proposed to be used as a bridge to characterize these findings in a more feasible way. In the present work, progress has been made to analyze …  Read more

In this thesis, I present a study of how elementary students used spatial visualization while engaging in geometric tasks. In particular, I examined: (a) students’ visualization practices when engaging in spatial visualization tasks in geometry, (b) the difficulties students encountered when participating in such tasks, (c) the differences between early, middle and late elementary students in how they used spatial visualization when solving geometric tasks and (d) the embodied resources the students drew upon to engage in spatial visualization when solving the geometric tasks. This research used case study methodology. I interviewed six elementary students and video recorded the interviews. …  Read more

Individuals with mental health problems (MHP) have, historically, experienced challenges with participating in physical activity and exercise (PAE). While programs have been created to promote PAE participation for individuals with MHP, it remains unclear how they may participate in PAE within the community. Hence, the purpose of this study was to explore perceptions of PAE participation in the community for adults with comorbid MHP. The overarching research question was: How do individuals with MHP participate in community PAE? Semi-structured interviews were conducted with six adults with comorbid MHP for this single instrumental case study. Each person was participating in an …  Read more

Dengue, chikungunya, and Zika are three different arboviruses transmitted to humans by Aedes mosquitoes. These diseases have similar symptoms, are illnesses for which specific curative treatments do not exist, and for which sufficiently safe and effective vaccines are not yet introduced. Over the last 20 years, the burden of notified arboviruses has increased 15-fold worldwide. Particularly in Latin America, where Colombia and Brazil are experiencing up-to 60% of the overall arboviral burden. The heterogeneous distribution of these arboviruses across neighborhoods, socioeconomic strata (SES) and ethnic groups suggests that social determinants of health (SDH) are playing a role in their presence …  Read more

The ability of in-flight icing numerical codes to account for the effects of Supercooled Large Droplets (SLD), which are droplets ranging from 50-1000 µm, is still somewhat limited. Solvers that simulate SLD in in-flight icing treat an ensemble of droplets adopting a macroscopic approach, making use of some heuristic correlations based on experiments or extrapolating SLD behavior from smaller non-SLD droplets. Alternatively, taking a microscopic approach and accurately simulating the physics of individual droplets can lead to higher fidelity models when replacing empirical data. Therefore, developing models of a single SLD droplet impingement and solidification can provide a framework that …  Read more

L’imagerie par résonance magnétique (IRM) est une technique d’imagerie non-invasive utilisée pour étudier les changements neurologiques associés aux maladies. L’analyse morphométrique d’IRM se concentre sur l’analyse de la taille et forme de régions du cerveau, constituant ainsi un outil pour observer les changements du cerveau. Bien que de nombreux outils de traitement des images aient été développés, la plupart ont été conçues pour les adultes. Cependant, de nombreuses maladies apparaissant pendant l’enfance, les études de neuroimagerie pédiatrique peuvent donc permettre de mieux caractériser l’étiologie et progression de ces maladies et fournissant de l’information pour l’amélioration des outils de diagnostic. Ces …  Read more

Di Giovanni, George (Supervisor1)  Read more

Russell Steele (Supervisor2)  Read more

Les traitements de cancers deviennent de plus en plus précis et puissants, mais aussiplus en plus spécifiques. A cause de cette spécificité, les nouveaux traitements ne fonc-tionnent pas pour chaque patient ce qui nécessite des tests d’efficacité pour chaquetraitement. Les standards courant pour ces tests sont lents et ne sont pas toujours pré-cis. Une autre option et d’utiliser la tomographie par émission de positrons dynamique(TEPd). Ceci est une modalité d’imagerie de médicine nucléaire ou le patient est injectéavec un traceur radioactif qui émit des positrons. Pendant un scan TEPd, le traceur estsuivi pour faire une image des fonctions biologique du …  Read more

Les zones de subduction produisent de grands tremblements de terre et des trémors tectoniques, et de nombreux modèles de trémors et glissement font intervenir des aspérités ou parcelles à l’origine de trémors dans des zones de cisaillement à fluage visqueux ou à glissement silencieux. Les trémors tectoniques se produisent à des profondeurs (dans la plupart des zones de subduction) dans le champ de stabilité des schistes bleus, et des échantillons exhumés renfermant les assemblages minéralogiques pertinents peuvent être utilisés pour étudier les styles de déformation dans les conditions de température et de contraintes où ont lieu les trémors et le …  Read more

This dissertation explores and critiques Canadian legal responses to surrogate motherhood. At the heart of this project is an empirical study (qualitative interviews) with twenty-six fertility lawyers in British Columbia, Alberta, Ontario and Quebec. These interviews offer new insights on how and why surrogacy contracts are drafted and negotiated, on disputes that have arisen between surrogates and intended parents, and on how lawyers interpret, apply and view federal and provincial surrogacy laws. When compared with traditional narratives about surrogacy, lawyers’ stories provide a more nuanced and complex picture of power dynamics between surrogate mothers and intended parents. They indicate that …  Read more

Durant les trois derni`eres d ́ecennies, le r ́egime de commerce international a port ́e uneattention accrue envers l’environnement. Tandis que ce d ́eveloppement est souventdiscut ́e en mati`ere ≪ d’environnementalisme ≫, il y a peu d’ ́evidence pour sugg ́ererque l’activisme soit `a l’origine du mouvement. Au contraire, la litt ́erature existantetend `a valider les doutes des ́economistes que ce r ́egime de commerce est davan-tage ≪ le protectionnisme d ́eguis ́ee ≫. Cet article consid`ere les liens potentiels entrel’activisme et l’environnementalisme dans les accords de commerce pr ́ef ́erentiels (lesACP). J’explore l’association entre l’environnementalisme ACP et l’activisme, les …  Read more

Millions of people worldwide suffer from bone loss and bone defects, and treatment remains a major challenge in orthopaedic surgery. Autologous bone grafts and allografts suffer from performance limitations including donor site morbidity, viral transmission, immunologic incompatibility, long rehabilitation time and structural failure. The need for new strategies for the treatment of bone defects is therefore urgent and must be searched on the side of synthetic materials. The ideal bone graft material must: (i) match the mechanical properties of healthy bone; (ii) be biocompatible and promote healing and (iii) degrade over time to be replaced by healthy bone. To this …  Read more

Nedic, Jovan (Supervisor1)  Read more

Epilepsy is a major neurological disorder that is under intense scientific and medical investigation. The emergence of seizures is associated with other comorbidities and decreases the quality of life of patients. In addition, around 30% of patients do not respond to standard line of treatment using anti-epileptic drugs (AEDs). Furthermore, it is still unclear how seizures arise in the otherwise healthy brain. Therefore, it is critical to have well developed models where a causal understanding of epilepsy can emerge. While the development of seizures has been studied in many animal models, such as those using electrical induction, deciphering the results …  Read more

An overwhelming majority of Black students in Québec (87.4%) attend school in the French sector, while 12.6% go to English schools. Accordingly, the majority of what we know about Black youth in the province is informed by the French language literature, which tends to emphasize these youths’ educational trajectories in relation to their immigrant status, despite what for many are long family histories in the province. This literature signals that a significant number of Black students experience academic delays or drop out, and that many complete their high school studies in the adult education or vocational sectors. The few studies …  Read more

Platt, Robert William (Supervisor2)  Read more