McGill University Thèses et mémoires publiés en 1997

Sea water samples were collected from different sampling stations along the Lebanese coast in the summer of 1994. Chemical, biological and physical analysis were conducted to assess the recreational water quality in Lebanon. Some 125 samples were then analyzed for the presence of Cadmium and Mercury by atomic absorption spectrophotometry. Cadmium content, holding a mean 0.77 $ mu$g/L, was generally low for most areas with only a few elevated readings in Tripoli (1.89 $ mu$g/L), Checca (1.83 $ mu$g/L), Kaslik (0.79 $ mu$g/L), Beirut (1.19 $ mu$g/L) and Ramlet Al-Bayda (1.77 $ mu$g/L). Mercury content, holding a mean value of …  Read more

Experimental autoimmune encephalomyelitis (EAE) is a central nervous system (CNS) disease, with symptoms reminiscent of Multiple Sclerosis. During disease, the CNS is infiltrated by immune cells, with increased expression of MHC antigens and Th1 cytokines. We asked whether antigen presentation in the CNS controls the bias towards Th1 cytokine in mice. We examined the capability of microglia to act as antigen presenting cells. We found that they stimulated T cell responses in vitro, but supported increased production of Th1 cytokines only. We also found that IL-12 mRNA was upregulated during peak disease, produced by resident microglia. We therefore propose that …  Read more

The innovative process of removal of toxic heavy metals from water by biosorption, using the dead biomass of Sargassum marine alga packed in flow-through columns, was examined. The mechanism of uptake of Cu 2+, Zn2+, Cd2+, Fe2+, and Cr(III) by the biomass was identified as ion exchange taking place at the weakly acidic functional groups embedded in the cellular matrix of the seaweed. After pretreatment with mineral acids, the cation exchange capacity of the biomass was approximately 2.3 meq/g of biomass dry weight which is comparable to the metal binding capacities of commercial ion exchange resins. The issues related to …  Read more

Experiments were conducted to assess the variation for resistance to Fusarium graminearum ear rot among selfed lines from the Zapalote Chico corn population. It was already known that Zapalote Chico possesses some resistance to corn earworm (Heliothis zeae) and variation in Fusarium graminearum ear rot symptom severity had been observed within the population. During two years of experiments, 47 S4- and S5-generation lines were inoculated and ear rot severity was assessed. In addition, eight pigmentation traits and eight morphological traits were recorded. Lines showed significant differences for all recorded traits. Associations were not strong among morphological traits, but were fairly …  Read more

This thesis is concerned with AIDS cultural activism. Specifically, it examines artistic responses to the medical/scientific image of HIV that circulates widely in the mainstream press. Examples of AIDS science reporting that focus on the medical/scientific image of HIV are selected from popular American news journals. It is argued that science and journalism are different and mutually dependent domains of knowledge, neither of which can be examined without the other. AIDS activist art engages with the relationship between science and the media and offers alternatives to the authority offered in science reporting. In the author's closing remarks, it is stated …  Read more

Squamous intraepithelial lesions (SIL) are believed to be precursors of in situ cervical neoplasia and of invasive cervical cancer. Though the burden of this disease has been greatly reduced thanks to the availability of an effective screening test, the worldwide morbidity and mortality remain high. On the basis of a classic approach to analysis of data from a prospective cohort study, I correlated HPV status at enrollment with subsequent risk of incident SIL during up to three years of follow-up among women of Brazil enrolled to the Ludwig-McGill cohort. The risk of occurrence of a first instance of SIL among …  Read more

Amyloid deposition in cortical plaques and around cerebral vessels is a hallmark of Alzheimer's disease (AD). Amyloid also accumulates, to a lesser degree, in some nondemented elderly individuals, in the cerebral cortex and in the choroid plexus (CP), a tissue in the cerebral ventricles which produces cerebrospinal fluid (CSF). The cortical amyloid is composed mainly of aggregates of a neurotoxic peptide called amyloid-beta (Abeta), of which there are two main variants, Abeta42 and Abeta40, but the composition of CP amyloid has not been determined, nor is it known if there is a relationship between amyloid deposition in these two locations. …  Read more

Evans, A. C. (Advisor)  Read more

Digestive proteases were isolated from the pancreas of the stomachless cunner fish (Tautogolabrus adspersus) and characterized in terms of their physicochemical properties, their ability to hydrolyze native pectin methylesterase (PME) from orange and polyphenol oxidases (PPO) from mushroom and the ability of the cunner enzyme(s) to maintain the stability of orange juice cloud. The cunner trypsin fraction exhibited exceptional capacity to hydrolyze native proteins versus the bovine trypsin. Incubation of native PME with cunner or bovine trypsin resulted in a loss of 75% or 35% in PME activity respectively. Similarly, a 75% or 55% loss in PPO activity was observed …  Read more

This thesis is a radical reinterpretation of the Hannover Merzbau ( Cathedral of Erotic Misery) by Kurt Schwitters. It proposes and demonstrates that two of Schwitters' own photographs of the work should not be viewed as being descriptions of a "constructed" Merzbau, but rather understood as complex constructions that generate a critical questioning of the modern site of perception. Through an exploration of language (as understood within Giambattista Vico's New Science) the photographs come to deconstruct themselves within a context of simultaneous readings; allowing both the "secret" space of the modern Merzbau, and the sacred place of the Cathedral to …  Read more

An amorphous-Selenium (a-Se) based portal detector, which uses the metal substrate as a conversion plate, is studied using Monte Carlo techniques. The optimal thickness and material of the metal plate and a-Se thicknesses are investigated by modelling dose deposition in the a-Se layer for a 6 MV exit beam. Simulations of Detective Quantum Efficiency DQE(f) show that although DQE(0) increases with metal thickness up to $d sb{max},$ there is a cross-over near 1 cycle/mm which indicates that smaller metal thicknesses are more useful to visualize edges and small objects. A similar cross-over, though not as prominent, is also observed with …  Read more

In this thesis techniques for fabricating fast contracting and relaxing shape memory alloy (SMA) fibers are presented. Shape memory alloy fibers have demonstrated the largest stress and highest power to mass ratio of any known actuator technology. However their practical application has been plagued by three major drawbacks, namely: (1) relatively slow expansion of the material despite rapid contraction; (2) problems of mechanically and electrically connecting to the material due to the violent nature of their contractions; and (3) low efficiency in the conversion of electrical energy or heat into mechanical energy. The work associated with this thesis has led …  Read more

The main objective of this research is to identify risk factors for severe playground injuries among children aged 1 to 14 years who visited the emergency room of a paediatric hospital in Montreal, during the summer of 1991. Secondary objectives are to study determinants of the occurrence of playground injuries, to estimate injury rates adjusted for exposure, and to do recommendations for prevention. To document circumstances of each injury, telephone interviews were completed with parents of children and a response rate of 90% was obtained. The objectives of this research required different study designs. The principal objective was achieved through …  Read more

Progressive myoclonus epilepsy type 1 (EPM1), also known as Unverricht-Lundborg disease, is one of the rare forms of epilepsy that shows a clear pattern of autosomal recessive inheritance. The gene defective in this disease was linked to the distal tip of chromosome 21, in band q22.3. In this study, we have collected 93 samples from 15 EPM1 families and 5 affected individuals as the basis for identifying the EPM1 gene. We have also constructed a 770 kb cosmid and bacterial artificial chromosome contig covering the candidate EPM1 region, and have isolated expressed sequences from this contig. For three of the …  Read more

The compilation of albums began almost upon the invention of photography and has continued to this day, migrating now into the realms of electronic and digital imagery. The private album, which includes, but is not limited to, the family album, is a hybrid of flexibility and conservatism--situational, syncretic and personal in its contents and organization. Interpretation of an album is correspondingly challenging, especially when the album has been separated from its compiler and placed in a public collection. The McCord Museum of Canadian History has a substantial collection of private albums ranging in date from the 1860s to the 1960s. …  Read more

Statistics corroborate the substantial and deleterious impact of substance abuse to both client and client systems. Social workers are regularly exposed to clients who are directly or indirectly affected by substance abuse. A random survey of social workers working with Anglophone and Allophone populations on the island of Montreal was conducted to evaluate the workers perceived ability to recognize and respond to the needs of this client group. Links were drawn to the various ways in which social workers developed their knowledge about addiction and to the worker's formal social work education. The study demonstrates the inadequacy of the formal …  Read more

Array dependence analysis is all important component of any optimizing/parallelizing compiler. The results of array dependence analysis are required by many parallelizing transformations as well as other analyses for further optimizations. This thesis is concerned with a symbolic framework for array dependence analysis. It has been shown that the presence of unknown symbolic values in array index expressions occurs with significant frequency such that the accuracy of array dependence analysis is compromised. The use of helper analyses such as constant propagation, resolves the problem in some situations, but in general the development of symbolic array dependence analysis is needed. This …  Read more

Cracking is one of the most serious problems affecting concrete structures. It is important to repair them to maintain their level of service. In 1987, after experiencing problems during the injection of one of its concrete dams, Hydro-Quebec decided to carry out a research project to investigate the grouting products, equipment and procedures. This thesis is a part of these activities. The topics treated in the first chapter are concrete cracking and its investigation. Then, follows a brief description of concrete repair techniques, including examples of grouting. The next chapter describes the products, equipment and procedures used in concrete grouting. …  Read more

Safety of a building's occupants is of primary concern in the design of a building. However, geophysical hazards such as earthquakes, still pose dangers to occupants of buildings. In an earthquake-resistant structure, even during a moderate shake, objects which are part of non-structural systems, accelerated by the sudden motion of the building, can hurt building occupants and cause damage to their property. The adoption of simple earthquake precautionary measures, could almost entirely eliminate this hazard. The adoption of these actions is the responsibility of occupants themselves, as part of their response to earthquake risk. Previous personal experience with earthquakes has …  Read more

Nine distinctive bacteria were isolated from a diclofop-methyl-degrading-consortium biofilm and their genomic DNA extracted for genetic characterization. With one exception, all the isolates contained plasmid(s). The consortium degrades diclofopmethyl producing a number of metabolites that are intermediates or substrates for bacteria that degrade chlorinated aromatic compounds. Accordingly, specific catabolic gene PCR primers for chlorinated degradation pathways were designed and tested to determine if these genes are involved in diclofop-methyl degradation. DNA homology analysis between the PCR products and the known catabolic genes investigated by Southern hybridization analysis and by sequencing, suggested that novel catabolic genes are functioning in the isolates. …  Read more

Lamonde, Yvan (Supervisor)  Read more

Long term care placement consists of determining an individual's need for care and services and of allocating appropriate resources. In Quebec, this laborious process includes a standardized application form. This study examined the work burden incurred and its cost to the system: Social workers in nine Montreal anglophone hospitals as well as in receiving resources were surveyed; the principal researcher of the 'Classification by types of program in extended care and service facilities' project was interviewed; the committee processing these forms was observed; Canadian hospitals were surveyed for comparison with Quebec. The findings show that the application form requires unnecessary …  Read more

Constance de Salm (1767-1845) is an unknown French woman author who nevertheless enjoyed much success in her time. The French Revolution of 1789 and the disappointments that it brought in regards to woman's rights incited her to also use her writings to forward women's cause. In this work, we will first introduce this "illustrious unknown writer" through a biography relating the important periods of her life while also drawing a parallel with the literature she wrote during her career. We will then go over those "feminist" writings in order to focus on the major themes.  Read more

This thesis is an examination of the double motif used by Charles Dickens in A Tale of Two Cities, Great Expectations, and Our Mutual Friend. There is a subtle shift that takes place in these last completed works, from a double motif which is used to prescribe individual behaviour along the lines of domestic or Christian ideology, to one which examines the social and psychological consequences of the individual's submission to such ideological imperatives. In fine, Dickens begins to distance himself from the stock, physical double he had inherited, turning instead to a double that finds its causes and ramifications …  Read more

De Mori, Renato (Supervisor)  Read more

In order to identify a homologue of the cell division cycle regulatory kinase P34cdc2 that may function in the nervous system, a mouse brain cDNA library was screened at low stringency using a cdc2 cDNA probe. A 2.5 kb cDNA was isolated that contains a 423-amino acid open reading frame encoding a novel cdc2-related protein kinase that was named PFTAIRE, because of the consensus PSTAIRE-like motif (single letter amino acid code) characteristic of cdc2 kinase family. The novel PFTAIRE is most homologous to the PCTAIRE class of cdc2-related kinases because of similar N- and C-terminal extensions lacking in many other …  Read more

The purpose of this thesis is to develop a new barotropic ocean model to study ocean dynamics. The model combines for the first time the flexible finite-element method and an accurate semi-Lagrangian advection scheme on unstructured triangular meshes. In the first part of the work, the semi-Lagrangian method is used for advection experiments on an irregular grid. A cosine hill is advected using a specified flow field corresponding to solid body rotation. A major difficulty is to find an interpolator which is at least fourth order accurate on an unstructured mesh. Such accuracy is needed for the treatment of slow …  Read more

Alzheimer's disease (AD) has been shown to involve impairments in both cognitive function and affective behavior. Animal models of AD, to date, have largely ignored the affective components of the disorder. Therefore, we investigated whether nucleus basalis magnocellularis (NBM)-lesioned rats, an animal model which mimics some of the cognitive deficits associated with AD, would display behavioral alterations on tests evaluating anxiety. We also tested the ability of neural transplants to normalize lesion-related changes in anxious behavior, as it has been demonstrated that grafting embryonic cholinergic or adult chromaffin cells can ameliorate NBM lesion-induced deficits in cognitive abilities and reverse lesion-related …  Read more

Mucciardi, Frank (Advisor)  Read more

The structural and magnetic properties of Diamagnetic/Ferromagnetic: Cu/Fe multilayers, prepared by DC-magnetron sputtering, were studied as a function of Fe layer thickness tFe. Structural characterization reveals the successful growth of high-quality layered structures along the film growth direction. However, the increasing contribution of the interface roughness was visible with decreasing tFe . X-ray diffraction data indicate the dissolution of Fe atoms in fcc Cu medium due to interfacial mixing. The magnetic transition from ferromagnetism to paramagnetism with decreasing tFe was confirmed by conversion-electron Mossbauer spectroscopy (CEMS), vibrating sample magnetometry, and magnetotransport measurements. The monotonic decrease in the average hyperfine field …  Read more

As digital video services become more prominent, the strain that they place upon networks will become more pronounced. The network of choice for carrying these transmissions will be the Broadband Integrated Services Digital Network using the Asynchronous Transfer Mode (ATM) transmission protocol. In particular, ATM is well suited for handling variable-bit-rate (VBR) transmissions because it is capable of statistical multiplexing. VBR coding is also advantageous because it is conducive for producing consistent image quality. This thesis outlines the conversion of a software MPEG-2 video coder to operate as a VBR coder and then as a traffic shaping one. The rate …  Read more

Physicians have traditionally withheld opioid analgesics from patients with acute abdominal pain due to concerns of masking physical findings. No study has examined morbidity and mortality after narcotic administration. The purpose of this study was to determine: (1) frequency of abdominal pain requiring narcotic analgesics, and (2) rate of serious outcomes, (death, infection, perforation, obstruction or hemorrhage of abdominal organs), in order to assess the feasibility of a randomized clinical trial on the safety of narcotics. Of 860 patients with acute abdominal pain, 477 (55%) completed a pain questionnaire, and 321 met study criteria for need of narcotic analgesia (37.3%). …  Read more

The properties of plastics products are governed by their crystallinity and morphology. In order to study the effects of processing shear stresses on crystallization behavior, a fiber pullout technique was applied in conjunction with polarized light microscopy and a hot stage. The shear apparatus consists of a single glass fiber sandwiched between two layers of polypropylene films mounted on the hot stage. At the crystallization temperature, shearing was introduced by pulling the fiber at a constant velocity for a fixed period of time. Static crystallization of the polymer then ensues. Computerized data acquisition and image analysis were employed to observe …  Read more

Oxidative stress activates the NF-$ kappa$B/Rel transcription factors which are involved in the activation of numerous immunoregulatory genes and the human immunodeficiency virus type I (HIV-1) long terminal repeat (LTR). In the present study, we examined the effects of established and novel compounds including antioxidants, ribonucleotide reductase inhibitors and iron chelators on NF-$ kappa$B activation and HIV LTR-mediated gene expression induced by TNF-$ alpha$. N-acetylcysteine (NAC), pyrrolidinedithiocarbamate (PDTC) and Trimidox (TD) at various concentrations inhibited TNF-$ alpha$ induced NF-$ kappa$B binding in Jurkat cells. Pretreatment of cells with these compounds prior to stimulation prevented I$ rm kappa B alpha$ degradation. …  Read more

An anthracnose-inducing pathogen, Colletotrichum dematium, was studied as a bioherbicide for Epilobium angustifolium. A comparative study involving other C. dematium isolates suggests that the isolate from E. angustifolium is a forma specialis and should be designated as Colletotrichum dematium f.sp. epilobii. The most severe damage was achieved on seedlings using a conidial density of $1 times 10 sp9$ conidia m$ sp{-2}$. Virulence decreased with plant maturity. Satisfactory levels of control were limited to long dew duration ($>$18 h) and high temperature treatments. Of various adjuvants tested, significantly higher levels of control were achieved when inoculum was sprayed in a vegetable …  Read more

A wealth of data supports the hypothesis that the neurotransmitter serotonin regulates the intake of ethanol, and is involved in the development of alcoholism in humans. Reduced functioning of the serotonergic system hypothetically increases alcohol intake in both animals and humans. In this thesis, it was proposed that the effect of lowered serotonergic function on alcohol intake is mediated by an increase in disinhibition. The hypothesis that lowered serotonin increases disinhibition was tested in separate groups of individuals at high risk for the development of psychopathology: nonalcoholic young men with a strong family history of paternal alcoholism, and adolescent men …  Read more

This thesis examines how a group of culturally and linguistically diverse Toronto secondary students perceive their present and previous writing experiences, ESL instruction and theories about writing in a first and second language. Data analysis included interviews with eight students, participant observations in their ESL classroom, literacy events and analysis of their written texts.  Read more

The thermal expansion behavior of Duralcan particle reinforced composite materials was investigated. Initially, the temperature dependence of the CTE of Al-Si alloy containing SiC reinforcement particles ranging from 10 to 40% in volume was experimentally examined and compared with standard theoretical model predictions. In addition, the effects of reinforcement volume fraction and nature of the composite constituents during thermal cycling between 25 and 350ºC were determined for Al-Si alloy containing between 10 and 40% SiC particles and Al alloy having 40% alumina in volume. Accurate experimental CTE measurements were made using a high precision Thermomechanical Analyzer system. Silicon carbide reinforced …  Read more

This thesis describes a real-time cardiac acoustic mapping system (RTCAMS) which displays the amplitude of the phonocardiogram (PCG) from the surface of the thorax through an acoustic probe composed of an array of 25 microphones. The essential components of the RTCAMS are the data acquisition, the graphic computation and display of the PCG envelopes and the acoustic maps. These processes are performed in parallel by distributing them in 2 digital signal processors (DSPs) on an add-on board in a personal computer (PC). Parts of the software for the DSPs are written in assembly language to improve the overall speed of …  Read more

Neurotrophins are dimeric polypeptides responsible for the survival, differentiation and maintenance of specific neuronal populations that express cell surface receptors termed tropomyosin receptor kinases (Trks). Trks possess intrinsic tyrosine kinase activity and are thought to mediate most neurotrophic effects. Recently, non-neuronal cells as well as certain human neoplasias, such as neuroblastoma have also been shown to express Trks. The prototype neurotrophin, Nerve Growth Factor (NGF) binds to the first identified Trk, TrkA causing its dimerization, auto- and trans-phosphorylation and subsequent cascade of signaling events. NGF also binds to a receptor with less well characterized biological activity termed p75. The production …  Read more

Knowledge of the clinical progression and prognosis of Alzheimer's disease (AD) is important for planning the care of afflicted individuals and evaluating the potential benefits of interventions. There is little consensus, however, regarding the prognostic importance of clinical and demographic characteristics investigated to date. This thesis examined the methodology of prognostic studies of AD through: (1) a critical review of published studies (1984-1995); (2) an assessment of the concordance among different methods of estimating annual rate of change; and (3) an evaluation of the assumption that decline in AD is linear. A review of 59 eligible studies revealed considerable methodological …  Read more

A cognitive process model is developed that predicts the 3 major symbolic comparison response time effects (distance, end, and semantic congruity) found in the results of the linear syllogistic reasoning task. The model assumes that people generate an ordering of a finite set of symbolic stimuli on the basis of information contained in the pairwise relations between adjacent stimulus items. The learning of this ordering is simulated within a simple connectionist framework. The decision-making component of the model utilizes 2 separate evidence accrual processes operating in parallel. One process accumulates information about the positional difference between the stimulus items being …  Read more

The biliary glycoprotein (BGP) is a member of the carcinoembryonic antigen (CEA) family, a subgroup of the immunoglobulin superfamily. BGP is down-regulated in many carcinomas. The mouse homolog of human BGP is Bgp1. It is a membrane-bound protein expressed in many types of epithelial and endothelial cells as well as in cells or the immune system. It functions in vitro as a cell adhesion molecule and can act as a tumor supressor. However, its physiological functions remain unclear. Histoimmunochemical studies of its expression pattern during development suggest that Bgp1 is active in epithelial differentiation, gut morphogenesis, absorption/reabsorption processes, myogenesis and …  Read more

This study was undertaken in an attempt to assess the Affect Intensity Measure (AIM) as a simpler alternative to the Overexcitability Questionnaire (OEQ) as a measure of emotional intensity in high ability young people. Participants were 30 young adolescents from grade 6 to grade 11 from the McGill Summer "Explorations" Program for the gifted, 75 undergraduate students and 46 doctoral students from various departments of McGill University. The Affect Intensity Measure was administrated to all three groups. There were no affect-intensity differences among the three groups of participants. Affect Intensity Measures particularly failed to distinguish gifted and nongifted groups. This …  Read more

Comedy and tragedy originated in Greece, from singing and dancing. By definition, dramatic art is an imitation of action. This artistic form was born during the passage from the archaic world to the democratic and classical Greece, and it is the ancestor and first form of philosophy. This birth was also shown in aesthetic ways by the historic and astonishing encounter of Apollo, the visionary god, the ultimate achiever in painting, sculpture and poetry, and Dionysos, the god of ecstasy, music and delirious action. The whole architecture of the ancient theatre, from antiquity to Renaissance, affords all the necessary support …  Read more

McLelland, J. C. (Supervisor)  Read more

This study was based on the 462 milk samples collected from approximately 2000 cows registered in Dairy Herd Analysis Service (DHAS). Milk samples from fresh milks were phenotyped by gel electrophoresis. Milk samples were selected according to the nine possibilities of phenotype combination of $ kappa$-casein AA, AB, BB and $ beta$-lactoglobulin AA, AB and BB. Selected milk samples from fresh milks were heated at 25$ sp circ$C, 60$ sp circ$C, 70$ sp circ$C, 80$ sp circ$C and 90$ sp circ$C, respectively. Whole casein and whey protein were separated by adjusting the pH to 4.6. Quantitative determination of milk protein …  Read more

A variety of extractants were used to fractionate the trace metals Cd, Cu, Mn, Ni, Pb, and Zn in contaminated urban soils. The metals were mostly held in soil solid phases but not in soluble and exchangeable forms. Except for Mn, extractability of metals by selective chemicals was mainly a function of the contamination level. The speciation of these elements in water, 0.01 M CaCl2, and pH-adjusted water extra was calculated using the chemical equilibrium model MINEQL+. The free ions of Cd, Ni, and Zn were the predominant species in most of the water and 0.01 M CaCl2 extracts while …  Read more

A lesion interface consisting of a glia limitans lined by a laminin-rich basal lamina forms within 3 weeks after leptomeningeal cells infiltrate into penetrating wounds in the adult mammalian CNS. This impedes axon regrowth. We have examined the effects of steroids on the formation of the lesion interface in the adult rat cerebral cortex. Topical glucocorticoids were applied on the surface of cortex encompassing stab wounds. Three weeks later, cryostat sections through the lesioned area were labeled with anti-laminin, anti-GFAP, anti-ED-1 and Nuclear Yellow. Steroid treatment attenuated all components of the lesion, including leptomeningeal cell infiltration. In vitro, steroid treatment …  Read more

Recent laboratory studies have reported on the success of electro-kinetic extraction of heavy metals from contaminated test samples, and have suggested that this would be a useful in-situ remediation technique. However, field studies have shown limited success and some contradictory results. The basis for successful application appears to be a judicious choice of soil type and parametric constraints. In this study, the surface charges of two soils (kaolinite and illite soils) are used as the primary control in the investigation of electro-osmotic extraction of lead---introduced as a contaminant into the soils. Four types of soils were used: pure kaolinite, illite …  Read more