McGill University Thèses et mémoires publiés en 2002

Neurotensin is a thirteen amino acid peptide that is found both in the central and peripheral nervous systems. In the CNS, it controls the synthesis and release of dopamine, modulates anterior pituitary hormone secretion, and provides non-opioid-receptor-dependent analgesia. In the gut, it modulates gastric acid secretion, pancreatic secretion, and colonic motility. In the immune system, it modulates IL-1 and mast cell secretion and stimulates macrophage phagocytosis. Neurotensin also acts as a growth factor for normal and cancer cells. Neurotensin mediates its effects through three neurotensin receptors: NTR1, NTR2, and NTR3. NTR1 and NTR2 belong to the G-protein coupled receptor (GPCR) …  Lire la suite

Introduction. Human papillomavirus (HPV) infection is now believed to be the central cause of cervical cancer. However, most of the epidemiological evidence has come from retrospective, case-control studies, which do not provide information on the dynamics of a cumulative or persistent HPV infection. Objectives. (1) To measure the risk of incident neoplastic cervical lesions over time related to prior cumulative and persistent HPV infections. (2) To evaluate the influence of HPV viral burden on lesion risk longitudinally. (3) To estimate the progression rates and sojourn time for precursor squamous intraepithelial lesions (SILs) and how they relate to HPV infection status. …  Lire la suite

A comparison of heart rate viability and respiratory sinus arrhythmia (RSA) characteristics was performed in 20 athletes and 12 age-matched sedentary controls (CTRL) (22 +/- 2.4 yrs). More specifically, this study examined the role of regular physical activity on the breathing frequency (BF)---RSA amplitude response curve comparing varsity swimmers (SW) to endurance runners (RU) to test the hypothesis that a locomotor-respiratory entrainment resulting from the water-immersion breathing pattern of swimmers would alter their respiratory related cardiac vagal integrative response. Spectral power components of HRV were computed from R-R interval sequences. Five-minute recordings were performed with subjects breathing either at their …  Lire la suite

Multiple Organ Dysfunction Syndrome (MODS) is the leading cause of mortality in Intensive Care Unit (ICU) patients. Although essential for host defense, the polymorphonuclear neutrophil (PMN) contributes to endothelial cell and end organ injury in disease states such as MODS. PMN chemotaxis and apoptosis are principally involved in neutrophil delivery and clearance, and their evaluation is performed with the goal of developing effective therapeutic intervention that would attenuate neutrophil mediated host injury. To investigate the role of neutrophil membrane receptor expression in the regulation of neutrophil apoptosis and chemotaxis, human circulating PMN (venipuncture, healthy controls), exudate PMN (skin window skin …  Lire la suite

Precup, Doina (Supervisor)  Lire la suite

Angenot, Marc (Supervisor)  Lire la suite

Circadian rhythms, ~24-h oscillations in physiological variables, are pervasive throughout nature. Synchronization of these oscillations to the 24-h day enables organisms to take advantage of environmental cycles. In mammals, a circadian pacemaker located in the hypothalamus coordinates the overt rhythms. The present study investigates aspects of the 24-h organization of breathing, and its chemical control, and of thermoregulation in mammals. Pulmonary ventilation (V˙E), oxygen consumption ( V˙O2 ), body temperature (Tb), and locomotor activity were monitored by non-invasive means, in freely-moving male adult rats. Rats are nocturnal, and it is well known that their Tb, activity and metabolic rate are …  Lire la suite

In this ethnographic inquiry, I examine the way in which literacy creates personal meaning in the lives of ten Hassidic women in Quebec, Canada. Using an integrative qualitative methodology, I draw from Goldberger, Tarule, Belenky and Clinchy (1996), theories of feminist notions of knowledge, current epistemological discussions about difference, power, multiculturalism, and the expression or suppression of voice. From Street's (1994) ideological model of literacy and from Barton (1994), Hamilton (1998), and Maybin (2000), I more clearly conceptualize the pivotal role of literacy practices in articulating links between individual people's everyday experience and wider social institutions and structures. Marilyn-Martin Jones …  Lire la suite

This thesis presents a new theoretical approach based on the concept of velocity singularities developed by Mateescu for airfoils in subsonic flows and for wing-body systems in supersonic regime. The present approach uses the velocity singularities in the Trefftz plane to derive the contributions of the wing incidence and chord changes in the solution of the circulation variation along the wing span. The new specific functions derived for these contributions contain both natural and forced symmetry and anti-symmetry terms, and represent the first correct mathematical modeling of the physical problem. The new forced symmetry and anti-symmetry terms and the new …  Lire la suite

Neurons from layer II of the entorhinal cortex (EC} occupy a pivotal position in the medial temporal lobe gating the flow of neocortical information into the hippocampus. Previous "in vivo" studies had shown that EC layer II generates theta rhythmicity, and "in vitro" investigations have demonstrated that the main population of layer II projection neurons, the stellate cells, display intrinsic theta-like autopacemaker properties. EC layer II cells receive important subcortical serotoninergic and cholinergic input from the dorsal raphe and basal forebrain, respectively, and these inputs are known to affect the population oscillatory behaviour of cortical neurons, including the "theta" rhythm. …  Lire la suite

Many hereditary peripheral neuropathies are characterized by abnormal myelination in peripheral nerves. Two structural myelin proteins, PMP22, a polytopic myelin protein, and P0, an Ig-like transmembrane protein, play a major role in myelin formation. A large number of mutations have been identified in P0 and PMP22 genes. Neuropathies associated with PMP22 and P0 mutations have varying severities suggesting their effects are pleiotropic. It is of great importance to explore molecular pathogenesis of mutated P0 and PMP22 proteins in order to understand the basic process of myelination and its pathology. We hypothesize that these mutations have a variety of effects on …  Lire la suite

Human immunodeficiency virus type 1 (HIV-1) genome consists of two identical RNAs that appear noncovalently linked near their 5' ends. The 5' untranslated region is called leader region. The 3' part of leader, i.e. nucleotides U200 to G335 in HIV-1 genomic RNA, between the primer binding site and the gag gene, can fold into 3 stem-loops: the kissing-loop domain (KLD) or stem-loop 1 (SL1), the 5' splicing junction hairpin (SD) or SL2 and SL3. The KLD, from nucleotide (nt) 243 to 277, forms a stem-loop (kissing loop hairpin) seated on top of a small stem bulge (stem B and loop …  Lire la suite

Ferrite grain refinement is one of the best methods to improve the mechanical properties of low carbon steels. The present work is a continuation of this past research and was conducted using a torsion machine. The aim was to improve the understanding of the strain levels and deformation temperatures required for UFF formation, as well as the influence of silicon addition. Two steels were studied: a low silicon (LSi) steel containing 0.09% C-0.02%Si-1.3%Mn-0.07%Al-0.036%Nb and a high silicon (HSi) steel containing 0.09%C-0.48%Si-1.2%Mn-0.02%Al-0.038%Nb. In the hot torsion tests, both steels were deformed to 5 true strain levels: 2, 2.5, 3.2, 3.5 and …  Lire la suite

Since the 1970s, the practice of deejaying has been integrated into music-making and musical performance in hip hop, dance music, and other cultures. Disc jockeys have also become recognized as producers and authors of sound recordings. I examine how changes in the technological, legal and commercial environment of disc jockeys in the 1990s are articulated in the styles and methods of deejaying. I argue that the conspicuous and covert styles of sampling articulate different forms of authorship, economic interests, and notions of originality. While the covert style has been crucial to the emergence of the DJ-as-author and deejaying as a …  Lire la suite

A series of experiments are described which explore the relationship between biomechanical properties and the control of jaw movement in speech. This relationship is documented using kinematic analyses in conjunction with a mathematical model of jaw motion and direct measures of jaw stiffness. In the first experiment, empirical and modeling studies were carried out to examine whether the nervous system compensates for naturally occurring forces acting on the jaw during speech. As subjects walk or run, loads to the jaw vary with the direction and magnitude of head acceleration. While these loads are large enough to produce a measurable effect …  Lire la suite

The liquid-liquid extraction of biomolecules using a reverse micellar system has been studied in literature as a simple and easily scalable purification method that can be used in fermentation industry. The recovery of proteins from the reverse micellar phase has shown a low efficiency (less than 20%) making the technique unfavorable in industrial practice. In addition, the modeling is often complicated due to the complex interactions among surfactants, cosurfactants, electrolytes and charged biomolecules. Thus, this work was aimed to examine the solubilization behavior of lysozyme into four different reverse micellar systems, in order to better understand the extraction mechanism. The …  Lire la suite

Greer, Charles W. (Supervisor)  Lire la suite

Transfer pricing is an area of major concern for tax administrations. The growth of multinational enterprises and an increase in cross border transactions has highlighted the significance of a regulated transfer pricing system. However, this regulated system imposes high penalties for improper transfer pricing. To reduce the risk of high transfer pricing penalties, multinational enterprises have resorted to advance pricing agreements with tax administrations. These agreements, though, are not a simple solution to reduce the risk of penalties. The process of executing these agreements carries with it the major drawback of information disclosure. Given this drawback, the APA programs in …  Lire la suite

Human prostate cancer is one of the most common malignancies affecting men. It is associated with a high degree of mortality and morbidity due to the development of non-skeletal and skeletal metastases. A common complication in patients suffering from prostate cancer is the development of hypercalcemia of malignancy. While determination of PSA and PSP-94 levels can serve as diagnostic/prognostic markers, PSP-94 can also serve as a therapeutic agent. The efficacy of PSP-94 to block tumor progression and hypercalcemia of malignancy was tested in our syngeneic in vivo rat model of prostate cancer. Rat prostate cancer Mat Ly Lu cells were …  Lire la suite

This thesis serves to analyze how autobiographical memory is deployed in the current series of the Montreal artist, Susan Shulman. Her cycle of nine works entitled In Our Memories Forever (1998--2001) are created based on the archive of photographs and letters written between her maternal grandparents at the turn of the nineteenth century. This essay will discuss cognitive theories on memory and specifically autobiographical memory types in order to examine the construction of memory in Shulman's series of paintings. A thorough investigation of the works themselves will be included. This examination will culminate with a look into how reconstruction theories …  Lire la suite

The middle ear is a small air-filled cavity which contains a chain of three small bones or ossicles: the malleus, the incus and the stapes. There is a tiny bony bridge (pedicle) between the long process of the incus and the lenticular process, but little or nothing is known about the effect of the pedicle on the movements of the ossicles. The motivation of the work presented here is to improve our understanding of the mechanical behaviour at the pedicle and the incudostapedial joint, in particular the relative contributions of the two structures to sound transmission through the middle ear. …  Lire la suite

Gray-Donald, K. (Supervisor)  Lire la suite

Myelin-associated axon growth inhibitors such as Nogo and myelin-associated glycoprotein (MAG) play an important role in the failure of axon regeneration in the adult mammalian central nervous system (CNS). One strategy to neutralize these inhibitors is a vaccination approach using immunization with myelin in incomplete Freund's adjuvant (IFA). In the present study, I compared the effectiveness of (i) immunizing with recombinant MAG/Nogo versus myelin, (ii) different adjuvants (IFA vs Alum) and (iii) different immunization frequencies for their capacity to promote spinal cord regeneration in adult SJL/J mice. The length of axon regeneration was similar in all the groups studied. However …  Lire la suite

The growth of computer-mediated communication (CMC) has generated great interest among researchers. Although perspectives vary, the anonymity inherent in textual communication and the reduction of social markers are often described as the characteristics that distinguish CMC from other forms of communication. These arguments have resulted in unprecedented optimism regarding the potential of this technology to eliminate social inequalities and increase access to institutional power. While critics have provided substantial evidence to the contrary, especially in regards to gender inequalities, CMC continues to be promoted and accepted. Critical responses on the issue of gender have concentrated on behavioral issues. As exemplified …  Lire la suite

The current study examines the agnostic Buddhism of contemporary scholar and practitioner Stephen Batchelor. The main question under examination is whether the essence of Buddhism is undermined when interpreted through Batchelor's agnostic and "belief-free" lens. In an attempt to answer this question, Batchelor's main philosophical texts---Alone With Others, The Faith to Doubt, and Buddhism Without Beliefs---are analysed, as are three critiques of his work written by Bhikkhu Punnadhammo, Bhikkhu Bodhi, and Sangharakshita. It is concluded that while Batchelor is discarding many of the conventional trappings of Buddhism, he is not placing its integrity at risk.  Lire la suite

An emerging application for computer vision systems is satellite servicing, involving pose estimation and tracking. Trackers are available but they often require initialization, considerably reducing autonomy. This thesis presents a new hierarchical pose estimation technique based on view-based analysis. The method can handle very sparse range data, is computationally efficient, is robust to noise, and can handle virtually any type of range data. It partitions the problem into two halves, one dealing with estimation of the translation and the other with the orientation. This greatly reduces the complexity of the overall problem without compromising the accuracy of the solution. The …  Lire la suite

This thesis explores the design of an optical switch based on MEMS micromotors. A basic layout of the switch is presented and a scalability study is made. Micromotor designs were also studied and fabricated via the Multi-User MEMS Processes (MUMPs) foundry service. The resulting motors were tested to obtain both mechanical and optical measurements. From the results, it was shown that micromotors could be successfully built using the MUMPs process. Speeds ranged from 0 to 138 Hz, with activation voltages as low as 26 V. Successful motors had rotor sizes of 400 μm, with grating sizes of 80 μm in …  Lire la suite

The present study was designed to see if children with learning disabilities could be taught three-row, double-digit addition problems using a dot-notation method. Three children with learning disabilities were selected for the study. Prior to the intervention, these students used a combination of count-all and count-on strategies when solving addition problems and used concrete referents such as fingers or tallies. A multiple-probe design was used to evaluate the effectiveness of the intervention with the 3 subjects. The experiment consisted of a teaching phase where students were taught to touch and count the dots on numbers 1 to 9 in a …  Lire la suite

The human impression of the color of an object is the same whether it is viewed foveally or peripherally, despite the non-uniformity of the spatial distribution of the photoreceptors on the retina. It is proposed that it is precisely the changing retinal signal resulting from moving the eye that leads to the perception of color constancy. Adhering to a bilinear model, which provides a parametrization of surface patch and illuminant spectra in a scene, the problem addressed in this thesis is defined to be that of estimating these spectral parameters, given only the spectral response of the sensor. The inherent …  Lire la suite

This thesis explores processes of self-representation in Indigenous media by analyzing the work of a weekly newspaper, The Eastern Door, of the Mohawk community of Kahnawake, Quebec (Canada). The thesis examines articulations of power in relations between State and Aboriginal communities, demonstrating the importance of such a medium for the conceptualization of Aboriginal Nation and construction of identity in the contemporary context. The Eastern Door is an important vehicle for communicating Mohawk identity and nationhood, a role it consciously plays, as part of its commitment to political autonomy. Its commitment is shown by its discursive explorations: of avenues, themes chosen, …  Lire la suite

Traditional telephone conferencing has been accomplished by way of a centralized conference bridge. An Internet Protocol (IP)-based conference bridge is subject to speech distortions and substantial computational demands due to the tandem arrangement of high compression speech codecs. Decentralized architectures avoid the speech distortions and delay, but lack strong control and have a key dependence on silence suppression for endpoint scalability. One solution is to use centralized speaker selection and forwarding, and decentralized decoding and mixing. This approach eliminates the problem of tandem encodings and maintains tight control, thereby improving the speech quality and scalability of the conference. This thesis …  Lire la suite

Non-additive effects may affect the evolution of populations by lowering the heritability of the traits that they affect, thus causing inbreeding depression within populations and playing a role in the conversion of non-additive into additive variation during bottlenecks and in the evolution and maintenance of negative genetic correlations between traits (Crnokrak and Roff 1995, Wolf et al. 2000). Furthermore, dominance variance should be present to a greater degree in traits closer to fitness (Crnokrak and Roff 1995). This study uses diallel cross analyses of inbred lines of the sand cricket Gryllus firmus, to examine the sources of variation in weight …  Lire la suite

This thesis has two main contributions. The first contribution is the development of a modular, easy-to-use Time Warp simulation engine targeted towards distributed-memory environments. The second contribution is the analysis and experimental verification of the performance of the flow control algorithm proposed by Choe in a distributed-memory environment. The Time Warp simulation engine TWSIM provides our laboratory with a research medium for Time Warp simulations in a distributed-memory environment such as a network of workstations. The modular design of TWSIM allows for easy integration of any new simulation application and for fast testing of optimizations and improvements to the Time …  Lire la suite

Regulators of G protein signaling (RGS) are proteins that negatively regulate G protein-coupled receptor signaling. Although a conserved core domain is necessary and sufficient for their GTPase accelerating protein (GAP) activity, many RGSs possess C- and N-terminal protein-binding motifs that augment GAP activity and participate in other cellular regulatory mechanisms. Human RGS 1 functionally complements a Saccharomyces cerevisiae mutant lacking the RGS homologue Sst2p. We demonstrate that deletion of the N-terminus or RGS domain negatively affects this ability in Sst2p-deficient strains, whereas deletion of the C-terminal 10 residues of RGS 1 does not. Coexpression of the N-terminus and RGS domains …  Lire la suite

Many a mechanical application involves power transmission from a high-speed motor to a low-speed load. However, existing speed-reduction mechanisms are usually a major sink of energy and information in mechanical transmissions. Energy and positioning information are lost through: (a) friction between sliding components; (b) compliance; and (c) backlash. A novel transmission for speed reduction, Speed-o-Cam, is currently under research at McGill University's Centre for Intelligent Machines (CIM). The transmission is based on the layout of pure-rolling indexing cam mechanisms, and hence, eliminates backlash and friction. Besides zero backlash and low friction losses, Speed-o-Cam also offers the possibility of high stiffness, …  Lire la suite

The motivation of the research presented in this thesis was to investigate the potential of using a commercial 2.3 kW heat pump dehumidifier (HPD) simultaneously as a dryer for high-moisture agricultural products and for other domestic dehumidification/heating applications. A drying system incorporating the HPD was designed and constructed, along with instrumentation to gather data on the properties of process air as well as real-time weight of the material being dried. The HPD was equipped with an external water-cooled condenser that rejected excess heat out of the system. The design of the system allowed for conducting drying with recirculation of air …  Lire la suite

Painchaud, Francois (Supervisor)  Lire la suite

Historical environmental changes in two shallow, unstratified, estuaries in Buzzards Bay, Massachusetts are compared, using three diatom paleo-production indicators: sedimentary biogenic silica (BSi), BSi flux and ratio of Centric to Penate diatoms. Both estuaries were exposed to pollution. New Bedford Harbor (NBH) has a history of intensive nutrient loading and industrial pollution, while the control site, Apponagansett Bay, has lower levels of nutrient loading. Consideration of local precipitation history and diatom parameters suggests that salinity-driven changes in diatom production are negligible. Over the past ~350 yrs, BSi concentrations and fluxes are higher in NBH. Thus, overall diatom production is sensitive …  Lire la suite

The impact of tillage and residue management on soil microorganisms was studied over the maize (Zea mays L.) growing season in southwestern Quebec. Tillage and residue treatments were imposed on a sandy loam to loamy sand soil in fall 1991. Treatments consisted of no till, reduced tillage, and conventional tillage with crop residues either removed from (-R) or retained on (+R) experimental plots, laid out in a randomized complete block design. Soil microbial biomass carbon (SMB-C), soil microbial nitrogen (SMB-N) and phospholipid fatty acid (PLFA) concentrations were measured four times, at two depths (0--10 cm, 10--20 cm), over the 2001 …  Lire la suite

HOX homeodomain proteins bind short DNA sequences to control very specific developmental processes. DNA binding affinity and sequence selectivity is increased by the formation of cooperative complexes with PBX. PBX is a 430 amino acid protein that contains an atypical homeodomain which is a member of the three amino acid loop extension (TALE) class of homeodomains. The three amino acid loop extension of PBX is required for formation of cooperative complexes with HOX proteins, and contacts a conserved YPWM motif in the HOX partner. The amino acids immediately C-terminal to the PBX homeodomain increase the affinity of the homeodomain for …  Lire la suite

Landolt, Hermann (Supervisor)  Lire la suite

In this thesis, an analytical investigation of the dynamics of three-body tethered satellite systems is presented. The analysis is performed for two cases: two-dimensional and three-dimensional motion. At first, the equations governing the motion of such systems are obtained assuming that the system center of mass moves in a circular orbit around the Earth. Then, the various equilibrium configurations are obtained. The equilibrium configurations are classified in eleven groups. Three of these groups are collinear configurations, and the others are triangular configurations. A stability analysis is performed for each equilibrium configuration. It is found that two of the collinear configurations …  Lire la suite

There is a 5--8% excess of winter-births among schizophrenia patients. This could be due to prenatal exposures to seasonally varying factors. Although winter-born and non-winter-born patients tend to differ in various aspects of the illness, associations between season of birth and premorbid adjustment (PMA) are unclear. Objectives. The main purpose of this study was to determine whether winter-born and non-winter-born schizophrenia patients differ in terms of PMA and to examine how family history may influence the association. A second objective was to determine which of the proposed underlying seasonal factor, and during which trimester of gestation, explains the most variance …  Lire la suite

We give a detailed proof of a theorem of P. Deligne on Tannakian categories. This theorem states that any tensorial category over a field of characteristic zero whose objects have nonnegative integral dimension admits a fibre functor over an affine scheme. We emphasize the category theoretical aspects of the subject.  Lire la suite

It is widely recognized that differences in both prosodic complexity and position-sensitive contrasts exist both within and across languages. In contemporary phonological theory, these differences are often attributed to differences between heads and non-heads and the asymmetries in licensing potential that exist between such positions. In this thesis, the consequences of such differences for the second language (L2) acquisition of prosodic complexity and position-sensitive contrasts are explored. It is argued that an explanatorily adequate account of L2 syllabification must include highly-structured representations as well as a theory of licensing, which distinguishes between the licensing of a given position and the …  Lire la suite

To capitalize on the efficiency and simplicity of wheeled robots, as well as the adaptability and maneuverability of legged robots, many hybrid leg-wheel designs have been developed. To date, none of these platforms have possessed the ability to execute dynamic maneuvers and thus have major shortcomings in their speed, efficiency and obstacle negotiating capabilities. A hybrid leg-wheel quadruped capable of such dynamic behaviour is introduced. Using an accurate model of this platform, a variety of dynamic behaviours and examples of their utility were successfully simulated. Passive leg compliance and the placement of wheels at the foot of the legs proved …  Lire la suite

This thesis is an examination of the concept and the term "superflat" as it is elaborated by the Japanese artist Murakami Takashi in his writings, in the exhibition he curated under the same name, and in his own art. Its aim is to contextualize Murakami's project on one hand in terms of a similar attempt to define a Japanese national aesthetic in the early 20 th century, and on the other in terms of the 1990's tendency to return to Edo Japan to find the "origins" of Japan's postmodernity. Murakami's own art is then turned to in order to both …  Lire la suite

Social change strategies grounded in theory help change agents to be more effective in their efforts. This study attempts to make explicit the links between public education efforts and the social change goals of non-profit organizations through an examination of both radical humanist thought and various social change theories. This thesis maintains that public education is an essential component of lasting change, serving eleven identifiable roles in the social change process. Of particular note, education can serve to challenge the dominant corporate paradigm and to develop an informed, critical, and more active citizenry. Education can also help create an environment …  Lire la suite

Chan, Laurie (Supervisor)  Lire la suite

The East Lake Zone is located within the Raglan horizon of the Cape Smith Foldbelt and hosts an ultramafic dyke/sill complex. The ultramafic units intrude both Raglan horizon siltstone as well as volcanic and volcaniclastic rocks of the Povungnituk Group. Magnesium, silica and chromium variation along with analyses of fresh olivine grains from the East Lake Zone indicate the ultramafic rocks were formed by olivine and chromite accumulation in a magma containing 11--13 wt % MgO. Rare Earth Element profiles of intrusive margins and some Chukotat Group pyroxene-phyric basalts show Light Rare Earth Element enrichment consistent with contamination by Raglan …  Lire la suite