McGill University Thèses et mémoires par auteur commençant par A

Komarova, Svetlana (Supervisor2)  Lire la suite

Misra, Arun K. (Supervisor1)  Lire la suite

Time-mode signal processing (TMSP) is becoming an increasingly popular candidate for replacing conventional analog/mixed-signal processing techniques such as those used in switched-capacitor circuit implementations. Traditional methods are based on the direct manipulation of information expressed in the form of voltage, current or electric charge. As such, these methods are suffering from the adverse effects of technology scaling such as supply voltage reduction, finite output impedance,...etc. However, unlike voltage resolution, time resolution actually improves from one technology node to the next which led to the high demand for TMSP.As a bonus, time-mode variables can be represented using two-level (digital) signals which …  Lire la suite

Swidan, Andraws (Internal/Supervisor)  Lire la suite

Several studies support that alpha-synuclein (aSyn) pathology transfers in a prion-like behavior via axonal projections. However, the mechanism that translates aSyn pathology spread to disease progression in Parkinson’s disease (PD) remains unknown. Here, we investigated the atrophy progression pattern in a longitudinal dataset of PD patients seen at baseline, one, two, and four years of follow-up. Then, we applied the agent-based Susceptible-Infected-Removed (SIR) dynamic model to simulate the spread of misfolded aSyn. We demonstrate three main findings. First, atrophy was significantly progressed over four years in subcortical and cortical regions based on deformation-based morphometry maps extracted from T1-weighted MRI data. …  Lire la suite

La recherche d’architecture neuronale (NAS) sensible au matériel et les méthodes pour optimiser la planification et le mappage sont utilisées pour trouver des implémentations efficaces de modèles de langage coûteux en ressources de calcul tels que BERT. Cela requiert de mesurer la vraie latence d’inférence sur le matériel ciblé : les bonnes décisions de conception ne peuvent tout simplement pas être prises avec des indicateurs approximatifs comme le nombre d’opérations en virgule flottante par seconde (FLOPS) ou le nombre de paramètres. Cependant, le temps requis pour effectuer ces mesures de latence directement sur le matériel cible est prohibitif (p. ex. …  Lire la suite

In this thesis we investigated the use of suspended graphene in nano-electromechanical variable capacitors (varactors) and other devices. The superior electrical and mechanical properties of graphene offers promising performance improvement compared to traditional micro-electromechanical systems (MEMS). We have explored the theoretical limit of the suspended graphene varactor, where the capacitance is tuned through the deflection of suspended graphene membrane under electrostatic actuation. Capacitor tuning of 76% is predicted, which exceeds the 50% limit of traditional parallel plate varactor. Actuation voltages as low as 1V can be achieved due to the low flexural rigidity of the suspended graphene. The non-linear response …  Lire la suite

Labeau, Fabrice (Supervisor1)  Lire la suite

Mine developments such as haulage drifts and cross-cuts are the primary access to the mining blocks of an orebody in multilevel mining systems for tabular ore deposits. Thus, their stability is of utmost importance during the planned period of production or the life of a mine plan. Many Canadian underground mines use longitudinal and transverse stoping with delayed backfill to extract tabular ore deposits. These methods require access to the orebody through a number of sill drives or cross-cuts which link the orezone to the haulage drift hence creating intersections on multiple levels. Mine development instability could lead to serious …  Lire la suite

Natalie Dayan (Supervisor1)  Lire la suite

Cette thèse étudie la validité et l'utilité d'une mesure prometteuse des résultats chez les patients subissant une arthroplastie totale de la hanche et du genou (respectivement THA et TKA) : l'analyse de la marche portable et sans marqueur. L'analyse de la marche a déjà été utilisée comme méthode objective pour évaluer la récupération après une arthroplastie. Cependant, les systèmes traditionnels de capture de mouvement en 3D sont coûteux, prennent du temps et ne sont pas pratiques pour une utilisation clinique de routine. Le premier objectif de cette thèse est de valider un système portable d'analyse de la marche sans marqueur, …  Lire la suite

Il a été démontré que des variables biomécaniques du genou lors d'un saut vertical en chute (SVC) sont associée à un risque accru de blessure sans contact du ligament croisé antérieur (LCA). Cependant, les systèmes standard d'analyse de variables utilisés pour quantifier les variables biomécaniques du genou ne sont pas pratiques pour le dépistage de routine. Ainsi, la présente étude sert à examiner les capacités de dépistage d'un outil d’évaluation portable utilisant les angles d'abduction coronale initiale (IC), d'abduction coronale maximale (PC) et de flexion maximale (PF) pendant un SVC pour évaluer le risque de blessure du LCA sans contact.Au …  Lire la suite

Three studies were conducted to determine the effects of nonstructural carbohydrate (NSC) sources on performance of dairy cows fed sunflower seeds. In the first study, the effects of NSC source on dry matter (DM) intake, milk yield and milk fatty acid composition were evaluated using fifteen lactating Holstein cows in a 3 x 3 Latin square design. In the second study, fifteen lactating Holstein cows were used in a completely randomized design to determine the effects of NSC on the total tract nutrient utilization. The third study was designed to determine in situ ruminal degradability of DM, CP, NDF and …  Lire la suite

$ beta$-Galactosidase (E.C. 3.2.1.23) or lactase was produced by the growth of a selected Bacillus subtilis strain (KL88) which was adapted to grow at 10$ sp circ$C. The growth and enzyme production were maximal at 2% (w/v) lactose supplemented with 0.2% (w/v) yeast extract. A Fast Protein Liquid Chromatography system (FPLC) was used for $ beta$-galactosidase purification. The enzyme was purified to 44-fold over the crude extract with a recovery of $ sim$54%. Native-PAGE and SDS-PAGE using "PhastSystem" showed the presence of two isoenzymes having molecular weights of 88 and 170 kD. The purified enzyme showed high activity at low …  Lire la suite

Residence time distributions {RTD) of meat and carrot cubes in starch solutions were evaluated in three stages in a commercial pilot scale aseptic processing system. In the first stage, RTD of meat (10, 15 and 20 mm) and carrot (6 &13 mm) cubes were investigated in the scraped surface heat exchanger (SSHE) of the aseptic system using a full factorial design of experiments employing flow rate (1 0, 15, 20, and 25 kg/min), starch concentration ( 4, 5 & 6% w/w). In the second stage, RTD experiments were conducted in the holding tube length (4.6, 9.2, 13.8 and 18.4 m) …  Lire la suite

Cette thèse propose une analyse du concept de l’indicible vis-à-vis de la traversée de l’Atlantique, étant un site d’archives et de mouvement à l’aide de deux récits de vie, soit Lose your Mother: A Journey Along the Atlantic Slave Route (2007) de Saidiya Hartman et le récit de vie de Omar Ibn Said A Muslim American Slave: The Life of Omar Ibn Said édité par Alaa Alryyes (2011). Mes analyses revisitent ses récits à travers les concepts de témoignages, de la hantise, et de la fiction. Tout au long de ce travail, j’établis des liens avec l’islam à la fois …  Lire la suite

The emergence of antibiotic-resistant bacterial strains poses a major threat to public health worldwide. Currently, drug-resistant pathogens are responsible for hundreds of thousands of annual fatalities. The misuse and overuse of antibiotics is a major promoter for the development of drug-resistant pathogens. Rapid in vitro diagnostic tools are essential to tackle the current drug resistance crisis by allowing rapid detection of pathogen resistance profiles and reducing diagnostic uncertainty and drug misuse. Here, I present a point of care microfluidic device for capture of bacteria and phenotypic in vitro antibiotic resistance profiling in less than 1 hour. The device employs a …  Lire la suite

Les réactions en chaîne par transfert de charge jouent un rôle crucial dans les diagnostics cliniques, de l'amplification des acides nucléiques aux tests métaboliques, mais elles sont souvent entravées par des protocoles longs et complexes. Lorsqu'elles sont associées à des colorants médiateurs sensibles à la couleur, elles peuvent être analysées à l'aide de systèmes colorimétriques optiques, qui fournissent une lecture simple et fiable sans avoir recours à des équipements sophistiqués. Cependant, les approches colorimétriques sont limitées par leur faible sensibilité dans un délai d'exécution court (défini comme la durée entre le prélèvement des échantillons et la communication des résultats), ce …  Lire la suite

The subject of the thesis is concerned with the study of the turbulent spreading and the gravity spreading processes in surface jets and surface plumes influenced by the cross-flow. A total of five different discharge and cross-flow configurations were under investigation. They are, namely, (i) submerged jets in unconfined cross-flow, (ii) surface jets in deep and shallow cross-flows, (iii) surface plumes in deep cross-flow, (iv) full-depth jets in cross-flow and (v) full-depth plumes in cross-flow, reported in Chapters IV, V, VI, VII and VIII respectively. The effect of the gravity stratification, the effect of the free water surface and the …  Lire la suite

Un sous-groupe H du groupe libre F est inerte si pour tout sous-groupes K, le rang de l'intersection H ∩ K est inférieur ou égal au rang de K. Il est comprimé, si le rang de H est inférieur ou égal au rang de K pour tout sous-groupe K tel que H ≤ K. Dans cet article, nous introduisons la notion d'immersions de graphes hautement inertes, et démontrons l'inertie de leurs groupes fondamentaux. Nous utilisons la compression des sous-groupes inertes pour déduire des propriétés concernant la distributions des lettres dans leurs graphes. Notre résultat principal est la généralisation des sous-groupes …  Lire la suite

Dans le chapitre 1, nous démontrons que chaque complexe cubique Y qui est compact et à courbure non-positive, s’intégre dans un complexe cubique R qui est compact et à courbure non-positive, tel que chaque isométrie locale et partielle de Y s’éttend à un automorphisme de R. Nous démontrons un résultat similaire pour les complexes cubiques spéciaux sous conditions que les isométries locales satisfassent certains critères.Dans le chapitre 2, nous définissons la notion de hauteur dirigée d’une application de graphes et nous étudions la relation entre celle-ci et la notion de hauteur d’un sous-groupe. Nous démontrons qu’une application de graphes a …  Lire la suite

This historical and conceptual thesis examines the cultural and socio-economic situatedness of education and development in the different epochs of South African history from the arrival of the first European settlers in 1652 up to the present post-apartheid era. The project assumes that cultural domination is utilized for the creation and long-term maintenance of systems of learning that are embedded in colonial and exploitative relationships. These relationships are generally defined by the socio-economic development of the dominant group at the expense of subordinated populations. Moreover, the thesis argues that colonial, and specifically apartheid education in the South African situation were …  Lire la suite

Through technological progress, agricultural research and development (AgR&D) has in the past raised agricultural yields in the developing world, enabling small scale farmers to meet the domestic and foreign demand for farm products. In sub-Saharan Africa (SSA), where agriculture is the backbone of most economies in the region, AgR&D has been lagging behind compared to other developing regions. This study investigates the contribution of agricultural research to agricultural production in SSA by quantifying the impact of AgR&D on the technical efficiency of agricultural production in the region. We use a unique data provided by the Forum for Agricultural Research in …  Lire la suite

After years of decreases in global hunger, recent estimates from the Food and Agriculture Organisation showed that the number of undernourished people increased to 815 million in 2016 from 777 million in 2015. This reversal in trends suggests that new approaches are needed to tackle global food insecurity. Studies have shown that one potential approach is to reduce gender inequality; however, there are no studies looking at the global level and across regions, with internationally validated food security tools. This study fills this research gap by exploring the association between gender inequality and food security at the global level and …  Lire la suite

The overall objective of this research was to identify forage legumes and grasses, which competed sufficiently with weeds developing after tillage, to provide acceptable weed control in grain corn, without, however reducing corn growth, and to obtain a better understanding of the physiological aspects of competition, particularly light and nitrogen. Corn yields were not affected by forage seeding date (10 and 20 days after corn emergence), however yields were affected by the type of forage species used as an intercrop. Cultivation reduced weed populations in corn and the inclusion of cover crops provided some additional control (up to 10%). Crimson …  Lire la suite

This thesis presents a new method for the prioritization of maintenance and repair (M&R) activities related to engineering facilities. Only M&R that can be programmed into a two to three years budgeting cycle are considered in the ranking procedure. Tasks that are of an emergency nature and that must be accomplished immediately are beyond the scope of this thesis. The methodology is intended to assist in a rational allocation of M&R funds by generating a priority list of tasks based on component importances and conditions. The premise is that the most important component in the worst condition is given the …  Lire la suite

This dissertation studies three aspects of airfoil flows: (i) second-order theoretical solutions of airfoils in steady flows; (ii) unsteady solutions for oscillating flexible airfoils; and (iii) numerical analysis of airfoil flows at low Reynolds numbers. The first part presents simple and efficient analytical solutions in closed form for the velocity and pressure distributions on airfoils of arbitrary shapes in steady flows, which are obtained using special singularities in the expression of the fluid velocity. A second-order accurate method is first developed for airfoils in inviscid incompressible flows to simultaneously solve the symmetric and anti-symmetric flow components defined by coupled boundary …  Lire la suite

This thesis presents a method based on the velocity singularities for the analysis of oscillating airfoils. The method of velocity singularities has been originally developed by Mateescu for the analysis of the steady flows past airfoils. This method makes use of special singularities associated to the leading edge and ridges that directly represent the complex perturbation velocity. Closed form solutions were derived for the pressure distributions and for the aerodynamic forces and moments acting on the oscillating airfoils with or without oscillating ailerons. The solutions obtained with the velocity singularity method for steady flows past airfoils were found to be …  Lire la suite

In this thesis, we present large-area graphene-based ion sensitive field effect transistor (ISFET) as an attractive candidate for detecting ion concentrations in a solution on-site using a portable device. Graphene ISFETs are compact and low-cost sensors that can be used in real-time and on-site. They also offer a resolution that is comparable to a spectrophotometer and atomic absorption spectrometer (AAS), which are high cost, bench-top laboratory instruments ill-suited for on-site measurements. We have been using a semiconductor parameter analyzer (SPA) to operate graphene ISFETs but they share the same limitations as high cost, bench-top laboratory instruments. We used an SPA …  Lire la suite

The purpose of this thesis is to examine the causes of Islamist ideological moderation. It focuses on the role of discursive structures and social practices in bringing about this ideational change. Through an in-depth case study of the Muslim Brotherhood in Jordan, a discourse and practice analysis is conducted to provide a theory that traces this group's moderation as a process. The thesis presents the argument that the group's increasing moderation was a result of practicing politics in a structural environment that challenged them strategically and ideologically. Under these environmental conditions, significant contestation arose within the movement. Resolving these debates …  Lire la suite

Diffusion least-mean squares (DLMS) algorithms can serve as efficient and powerful learning mechanisms for solving distributed estimation and optimization problems over networks in response to streaming data originating from different locations in real-time. Owing to their decentralized processing structures, simplicity of implementation and adaptive learning capabilities, they are particularly well-suited for applications to multi-agent networks where the network energy and radio resources are limited. In this dissertation, we propose new DLMS algorithms with application to sensor networks and examine their performance under realistic environmental conditions. Within this framework, the contributions of the dissertation can be divided into three main parts.In …  Lire la suite

Defatted soybean was subjected to isolation procedures as follows: NaOH extraction/acid precipitation (NaOH-IE); water extraction/acid precipitation (H2O-IE); NaOH extraction/cryoprecipitation (NaOH-CP) and citric acid extraction/cryoprecipitation (CA-CP). NaOH-CP and CA-CP each resulted in precipitation of one protein mainly consisting of glycinin and beta-conglycinin, respectively. The proteins were subjected to polyacrylamide gel electrophoresis (PAGE), SDS-PAGE, size exclusion-chromatography (SEC) and differential scanning calorimetry (DSC) for characterization. PAGE, SDS-PAGE, SEC and DSC confirmed the homogeneity of NaOH-CP. The gelation properties and structural characteristics of NaOH-CP were investigated; the minimum protein concentration required for formation of a thermally-induced gel from NaOH-CP was 8%. With cold-set gelation, …  Lire la suite

Modification of the eutectic silicon in Al-Si alloys is traditionally performed by sodium and strontium addition. Although not traditionally used as a modifier, calcium also has the potential to modify the eutectic silicon in Al-Si alloys. Metallographic observation and thermal analysis studies in A357 alloy indicate that. when the cooling rate is quite low. Ca modifies the eutectic silicon. but the effect of Ca as a modifier is not as strong as is Na or Sr. When the cooling rate is high, a fully modified structure can be obtained with calcium. Recovery of Ca in the melt is high and …  Lire la suite

When bone is damaged, a scaffold can temporarily replace it in the site of injury and incite bone tissue to repair itself. A biodegradable scaffold resorbs into the body, generating non-toxic degradation products as new tissue reforms; a bioactive scaffold encourages the surrounding tissue to regenerate. In the present study, we make composite biodegradable and bioactive scaffolds using poly-DL-lactide (PDLLA), a biodegradable polymer, and incorporate Bioglass 45S5 (BG) to stimulate scaffold bioactivity. BG has an interesting trait when immersed in body fluid, a layer of hydroxycarbonate apatite, similar to the inorganic component of bone, forms on its surface. It is …  Lire la suite

Habashi, Wagdi George (Supervisor1)  Lire la suite

Zanazanian, Boghos (Supervisor2)  Lire la suite

Normal rabbit bone marrow cells, but not cells of the other normal lymphoid organs could transfer immunocompetence to lethally irradiated or tolerant allogeneic recipients. However, bone marrow cells of rabbits immunized 24 hours previously could not transfer immunocompetence with respect to the immunizing antigen. The bone marrow immunocompetent cell was identified as the antigen reactive cell (ARC) and not the antibody forming cell (AFC) by the use of allotypic markers. The ARC which were morphologically small lymphocytes, could be isolated by passage of the normal bone marrow cells through an antigen-sensitized glass bead column. Immunocompetence following irradiation correlated with the …  Lire la suite

In the present thesis, we study the change in structural properties induced by ion beam irradiation of Ni/Fe and Co/Cu bilayers using various x-ray scattering techniques. These bilayers exhibit interesting GMR and magnetotransport properties. We show that an N-step model is useful in simulating any given electron density profile. We test four different interface profile functions in fitting the reflectivity and conclude that the error-function profile best describes our samples. Different types of interfaces are introduced, namely graded and rough interfaces, together with a discussion of their representation and their effect on both specular reflectivity and non-specular x-ray intensity. We …  Lire la suite

La ferroptose est une forme unique de mort cellulaire régulée qui a été identifiée par le groupe de recherche Stockwell en 2012. Contrairement à d'autres formes de mort cellulaire telles que l'apoptose ou la nécrose, la ferroptose est induite par l'accumulation de fer et d'espèces réactives de l'oxygène (ROS), ce qui entraîne une augmentation du stress oxydatif et des dommages à la membrane cellulaire. La ferroptose a été associée à plusieurs pathologies hépatiques et cardiaques. En fait, l'accumulation de fer contribue à la progression des tumeurs et au dysfonctionnement cardiaque par le biais d'un stress oxydatif et d'une dysrégulation métabolique. …  Lire la suite

Rosenblatt, David (Internal/Supervisor)  Lire la suite

La mauvaise nutrition et l'insécurité alimentaire restent courantes chez les femmes rurales ghanéennes. Les interventions agricoles sensibles à la nutrition améliorant l'autonomisation des femmes et l'égalité entre hommes et femmes ont le potentiel d'influer sur les déterminants sous-jacents et immédiats de la nutrition des femmes et de la sécurité alimentaire des ménages. Le projet LinkINg Up (ClinicalTrials.gov NCT03869853), une étude quasi-expérimentale, a été mis en œuvre en tant qu'intervention agricole multisectorielle pour développer les activités et les services destinés aux femmes entrepreneures agricoles dans les zones rurales du Ghana. Cette thèse était intégrée au projet LinkINg Up afin d'étudier ces …  Lire la suite

The effects of vitamin E (VE) and Arginine (ARG) on humoral and cellular immunity in chickens were investigated in two experiments. The humoral immunity was measured by antibody responses to sheep red blood cells (SRBC) and maternal antibody titers to the infectious bursal disease virus (IBDV), while the cellular immunity was studied using the cutaneous basophil hypersensitivity test to phytogemagglutinin (PHA) and by counting subpopulations of T-lymphocytes. We used two levels of ARG: normal (NARG, 1.2% in feed) and high ARG (HARG, additional 0.3% in drinking water or 1% in feed in experiments 1 and 2, respectively); and three levels …  Lire la suite

This thesis presents the design and experimental results of a 7.3GHz notch image reject filter, combined with a 5.8GHz low-noise amplifier (LNA), for integrated heterodyne receiver front-ends. A new image reject filter implementation is proposed. Q-enhancement circuitry for on-chip inductors are used to optimize the depth of image rejection. Experimental results show that more than 62dB of image rejection at 7.3GHz can be obtained in a standard CMOS 0.18mum technology, while operating from a 1.8V supply. The LNA exhibits a gain of 15.8dB and an IIP3 of -5.3dBm while consuming 9mW of power. With maximum image rejection, the LNA-notch combination …  Lire la suite

This thesis proposes a seventh-order 0.05° equiripple linear-phase continuous-time filter employing, for the first time, instantaneous companding. The filter was designed and integrated in a mature bipolar process. The amount of boost (up to 13dB) and group-delay adjustment (+/-30%) are digitally programmable. The DC gain is controllable up to 10dB, and the -3dB frequency (fc) is tunable from 5 to 70MHz. The output swing for 1% THD is higher than 100mVpp, with a 1.5V supply. The filter consumes very low power (5--13mW for fc = 70MHz), compared to state-of-the-art implementations (e.g. 120mW for fc = 100MHz [1]). An approach to …  Lire la suite