McGill University Thèses et mémoires publiés en 1996

The work described herein represents a preliminary step in the characterisation of the human Tom20 protein and its role in the mammalian mitochondrial import machinery. A hexahistidine-tagged form of the human homologue of Tom20 has been over-expressed in Escherichia coli and purified under native conditions. This Tom20 protein has been shown, in these studies, to compete for the import of a matrix-destined mitochondrial precursor protein, pre-ornithine carbamoyltransferase (pOCT), into mitochondria isolated from a mammalian source (rat heart), as well as to directly bind the presequence-bearing pOCT in vitro. Furthermore, a protocol has been established for the isolation of import-competent outer …  Lire la suite

"Mudra" is the transliteration of a Sanskrit word meaning "symbol" or "gesture". This piece is inspired by the interaction of thoughts, breathing patterns, spontaneous bodily movements and sensations which can occur during the yogic practice of 'pranayam'. The work is written for flute/piccolo, oboe, clarinet, bass clarinet, bassoon, horn, trumpet, trombone, percussion, piano, four violins, two violas, two cellos, and two double basses. The piece is divided into twelve sections, clearly delineated by changes in harmony, texture, meter, and registration. As the music unfolds, seven rhythmic cells and four fixed-pitch collections provide the basis for rhythmic and harmonic development, or …  Lire la suite

Ingots of the semiconducting compound CuInSe$ sb2$ have been grown by the Bridgman method using a single sealed quartz ampoule for both the compound synthesis, from starting elements of copper, indium and selenium, and the subsequent crystal growth. The resulting ingots, containing monocrystals of up to 2 centimeters in one dimension, were free of microcracks, voids and free of adhesion to the inner wall of the quartz ampoule. This was made possible by the unique use of a coating of boron nitride deposited on the inner wall of the ampoule prior to charging with the elements. The boron nitride acted …  Lire la suite

Afin d'évaluer les effets de !'exposition au fluor sur la reproduction d'oiseaux mâles, des crécerelles d'Amérique (Falco sparverius) et des cailles japonaises (Cotumix japonica) ont été traitées avec du fluor de sodium pendant une période de temps prolonge puis couplées avec des femelles non traitées. Quarante crécerelles d'Amérique males ont été assignées de façon aléatoire a un des traitements suivants: 1,65, 3,3 ou 6,6 mg NaF ou une solution contrôle de 13,2 mg NaHC03 administres par gavage oral quotidiennement pendant 45 jours. Durant la première année tous les males ont été couplés avec des femelles non traitées dès la complétion …  Lire la suite

A knowledge-based expert system was developed to automatically assess the level of EEG abnormality of pediatric patients monitored in the ICU. The system receives six hours of 8-channel EEGs and classifies the background EEG as one of seven abnormality levels. A total of 188, six-hour EEGs were visually interpreted by a neurologist and used as training examples. Spectral band activity was computed; artifacts were rejected using a median filter with a hard-limiter. Quantitative variables reflecting amplitude, symmetry, Front/Back differentiation and time variability were then extracted based on the study of Pasupathy (1994). Relationships between quantitative measures and the neurologist's assessment …  Lire la suite

My study concerns the works of William James (1842--1910) and the Buddhist thinker Vasubandhu (circa fifth c.). In both cases there is a detailed examination of consciousness which looks at its physiological concomitants. Where James is concerned, this physiological study is found mainly within his Principles of Psychology (1890). In Vasubandhu's case the physiological preconditions of conscious life is inherited from traditional Buddhist psychology (skandhas), but are expanded into the Yogacara concept of the alaya-vijnana (storehouse consciousness). This novel form of consciousness has been interpreted as both a soul theory in Buddhism, and a form of metaphysical idealism. It is …  Lire la suite

The isothermal crystallization kinetics, spherulite morphology, and thermal behavior of the melt-crystallized optically active R and S polyenantiomers, their blends, and the stereoblock form of poly(epichlorohydrin) (PECH) and poly(propylene oxide) (PPrO) have been investigated using polarized light microscopy (PLOM), atomic force microscopy (AFM), and differential scanning calorimetry (DSC). The novel optically pure polyenantiomers of PECH were synthesized from the optically active monomers using a triethylaluminum$ cdot$water (1:0.6) catalyst, which was also used in the polymerization of the racemic monomer to an isotactic crystalline stereoblock fraction. The optically pure polyenantiomers and the stereoblock form of PPrO were obtained by the quantitative …  Lire la suite

This thesis outlines Nietzsche's view of Socrates in The Birth of Tragedy. Socrates is first argued to be the father of science and then, after having explained the artistic nature of the world and ourselves according to Nietzsche, Socrates' degenerative, nihilistic influence upon the world is detailed. Science is then explained to have originated in a moral perspective on the world, the latter growing out of self-denial, and ultimately illness. The "dying Socrates" is Nietzsche's symbol of science as a negative positing of the artistic forces one is, from whence Nietzsche concludes the impossibility of escaping from oneself by such …  Lire la suite

While effects of multispin modes have proven to be of utmost importance in Nuclear Magnetic Resonance spectroscopy, their roles in two intimately related fields--chemical exchange and intermolecular spin relaxation--have not been adequately explored. In a bid to improve theoretical understanding, this work presents the generalized symmetry-adapted form of the exchange superoperator, which allows for proof of the macroscopic symmetry principle. The results obtained for an $A sb2$-AB type exchange are used to explain the presence of paradoxical symmetry-forbidden signals in the spectra of parahydrogen labeled symmetric substrates such as acetylenedicarboxylic acid dimethyl ester. The implementation of the chemical exchange for …  Lire la suite

Whole cell extracts from fresh calf thymus glands were subjected to Polymin P fractionation and Q Sepharose chromatography. Three peaks of DNA kinase activity, designated SNQI, SNQII and SNQIII, were found in the supernatant fraction. Studies of SNQI have revealed an estimated molecular mass of 50-90 kDa by Superose 12 chromatography, and activity gel analysis following SDS-PAGE identified an active polypeptide of approximately 55 kDa. This enzyme preparation, purified 10,000-fold, phosphorylated 5$ sp prime$-OH-terminated oligodeoxyribonucleotides and double stranded DNA, yet was inactive on an oligoriboadenosine ladder. SNQI functions optimally at an acidic pH in 10 mM MgCl$ sb2$, but is …  Lire la suite

This thesis research addresses the problem of human representation in virtual environments (VE). Previous work done on Virtual Reality (ESOPE-RV) lacks an interface to produce dynamic, real-time interactive simulated human representation. The goal of this research was to create the McGill Virtual Operator as a stand alone, independent software application interfacing the Human Operator with various synthetic worlds. For the lower body, including the feet we use pedals to perform the navigation in VE giving a locomotive motion which is simple and acceptable. However, the upper body motion and especially the human hand articulation is much more complex because humans …  Lire la suite

Currently, in the fields of multi-ethnic literary and cultural studies in American, many critics and theoreticians concentrate on exposing forces of social and economic oppression against ethnic minorities and practices of cultural hegemony by the dominant culture. In the process, they often read characters in multi-ethnic American literatures as agents of resistance and counter-discourse. While it is valuable to recognize the subversive potential in these writings, it is equally important to expose their distinct, individual attributes. Accordingly, this dissertation explores the neglected double nature and "bi-cultural" presence of the subject in a branch of contemporary American literature that I designate …  Lire la suite

Derome, J. (Supervisor)  Lire la suite

The equilibrium properties of polymers end-grafted to an impenetrable interface, the "polymer brush", are investigated. Relevant concepts and techniques of statistical polymer physics are discussed; in particular, a simulation technique that is very efficient for studying polymer brushes is introduced. This technique is demonstrated through simulations of a well characterized polymer brush system. The results of original investigations of phase separation in polymer brushes are also presented. An instability in the lateral monomer density of a polymer brush is observed under sufficiently poor solvent conditions. The onset of this instability is found to agree with a previous prediction. A compositional …  Lire la suite

Chromogranin-A (CgA) and parathyroid hormone (PTH) are the two major secretory products of the parathyroid gland. While CgA is believed to be important for cell secretory activity, its precise function(s) remain to be fully elucidated. The effects of the active metabolite of vitamin D, 1,25-dihydroxyvitamin D$ sb3$ (1,25(OH)$ rm sb2D sb3)$ were investigated on parathyroid gland CgA mRNA in the rat. Parathyroid CgA mRNA levels increased in a dose-dependent manner in response to injections of 1,257(OH)$ rm sb2D sb3$ whereas PTH mRNA levels decreased. CgA mRNA levels were less sensitive to 1,25(OH)$ rm sb2D sb3$ than PTH mRNA levels. Having …  Lire la suite

Bochmann, G. V. (Supervisor)  Lire la suite

The thesis examines the impact of a partial switch to a share system in Canada on unemployment and inflation. Simulations with an independent Canadian macro model and Canadian data for the period 1973-1983 show that profit sharing will not always resolve unemployment and inflation, as claimed by Martin Weitzman. Some combinations of the share parameters resolve them, while others aggravate them. Thus, the combinations of the share parameters play a key role in terms of impact of the profit sharing on unemployment and inflation.  Lire la suite

Human Immunodeficiency Virus Type 1 (HIV-1) infection is characterized by relentless depletion of cells belonging to the CD4+ helper-inducer subset, leading to the appearance in the patient of a lethal state of functional immunodeficiency. Many mechanisms have been proposed to account for the virus-induced destruction of T cells, including direct cytopathic effects of the virus, induction of apoptosis, and killing of infected or bystander CD4+ T cells by the cytotoxic immune response. Also, since HIV-1 is a retrovirus, it has been proposed that, like mouse mammary tumor viruses (MMTV), it could encode a protein with superantigenic properties, which could, by …  Lire la suite

Increasing maize production in Trinidad & Tobago could reduce imports and lessen dependency on foreign markets for food and feed. A review of large maize development projects and a survey of maize farmers on small landholdings indicated that mechanized production of maize grain is technically and economically impractical. Maize is normally grown and harvested in the green immature stage by small-scale farmers as a fast, easy, and relatively profitable sideline vegetable crop. An imported hybrid and an improved local landrace (ICTA Farm Corn) yielded more green maize than a Mexican-bred locally-distributed variety, following early (June) rainy season plantings. Hybrid and …  Lire la suite

Derivatized $ beta$-cyclodextrin was used as mobile phase additive for the high performance liquid chromatographic resolution of amino acid derivative enantiomers while using an achiral C$ sb{18}$ stationary phase. Dimethyl-$ beta$-cyclodextrin gave improved enantioselectivity over the underivatized $ beta$-cyclodextrin. The effects of cyclodextrin concentration, pH, and methanol and buffer concentration on enantioselectivity and capacity factor were examined. $ beta$-Cyclodextrin and two derivatized cyclodextrins were utilized as mobile phase additives for the liquid chromatographic resolution of equilin and estrone as well as estrone from 2-, 4-, and 16$ alpha$-hydroxyestrone. $ beta$-cyclodextrin proved to be suitable in these separations but the modified …  Lire la suite

A qualitative study design was used to describe the quality of life as perceived by spouses of persons who have had a laryngectomy within the preceding two years to treat cancer. A convenience sample of 17 spouses of individuals with laryngectomies participated in this study. Data were collected through guided interviews. Data were analyzed according to Giorgi's (1985) phenomenological method of analysis. Spouses described their quality of life by referring to marital relationship, communication and life style. Spouses identified nine factors that affect their quality of life. These are stress, coping, social support, caring, knowledge, body image, uncertainty, emotional status, …  Lire la suite

This thesis discusses the impact of the snowmobile on the Inuit society in northern Canada and more specifically in Kangiqsualujjuaq (Nunavik). By drawing the portrait of traditional and modern habits of mobility, it is possible to understand the influence of the snowmobile--considered as micro-technology--on the fundamental structures of the Inuit society. More generally, the research illustrates the evolution of the means of transportion starting from the pre-contact period to the 1990's. Westernization of the Inuit society is not the consequence of only one item but the combination of many. Even if it is difficult to evaluate the influence of a …  Lire la suite

In this work we have re-examined the classical problem of nucleation and growth. We present a new model that combines steady-state homogeneous nucleation theory with the classical Lifshitz-Slyozov mechanism of growth. This model considers the substantial correlations between droplets and naturally incorporates the crossover from the early-stage, nucleation dominated regime to the scaling, late-stage, coarsening regime within a single framework, without ad-hoc assumptions. This is achieved by the development of a set of self-consistent interface equations which describe the decay of metastable states. The model is implemented numerically and some interesting dynamical behaviour is observed, including the reproduction of the …  Lire la suite

In optimizing the code for high-performance processors, software pipelining of innermost loops is of fundamental importance. In order to benefit from software pipelining, it is essential to: (i) find the rate-optimal legal schedule, and (ii) allocate registers to the found schedule (it must fit into the limited number of available machine registers). This thesis deals with the development of a software pipeliner that produces the best possible schedules in terms of required registers, thus, assisting register allocation. Software pipelining and register allocation can be formulated as an integer linear programming (ILP) problem, aiming to produce optimal schedules. In this thesis, …  Lire la suite

The purpose of this study was to describe and interpret cooperative learning in a secondary school physical education program. A multiple-method case study design was used to investigate the physical education environment. One eighth grade girls handball class in its first year of cooperative learning was compared to an eleventh grade girls handball class in its fourth year of cooperative learning. The qualitative inquiry included interviewing the students and the physical education teacher, taking field notes, and analysing relevant documents. A modified version of the task structure observational system (Siedentop, 1994) was used as a quantitative measure of the instructional …  Lire la suite

The Newfoundland Department of Health administers several rubella vaccination programs for the prevention of congenital rubella syndrome (CRS). This study examined the effectiveness of these programs by reviewing rubella susceptibility in the population at risk for CRS, assessing the predictive value of a rubella vaccination record, and evaluating the effectiveness of the postnatal rubella vaccination program. From 1989 to 1993, rubella susceptibility in women aged 15 to 44 averaged 4.6% overall, but was significantly higher in women aged 15 to 19 years, averaging 14%. The positive predictive value of a rubella vaccination record was 92% overall, but it differed by …  Lire la suite

We have coupled a 3-dimensional physical planetary geostrophic ocean general circulation model to different biological models to investigate the interaction between physical and biological processes. A 1-dimensional particle cycle model with two particle size classes has been developed and coupled to the physical model as well. The ocean model (Zhang et al., 1992) is based on the planetary geostrophic equations in spherical coordinates. The model equations include the full prognostic temperature and salinity equations. The momentum equations are diagnostic and include geostrophic balance, and a linear friction term in order to provide a western boundary current. The wind stress is …  Lire la suite

For almost 35 years the work carried out by the Brazilian artist Lygia Clark between the 1950s and until her death, in 1988, has attracted the attention of both Brazilian and European scholars and critics. Since special attention has only been given to her post-1969 work, the work carried out until 1969 has been overlooked. In particular, I would argue that through the incorporation of the human body Clark's 1959-1964 Bicho series is the first spatial performative strategy developed by Clark during the 1960s and against which all her subsequent production needs to be read. The present essay is thus …  Lire la suite

Metal ion production by minerals alone and in pairs was studied by solution analysis, extraction with ethylene diamine tetraacetate (EDTA) and laser ion mass spectroscopy (LIMS) for combinations of pyrite, pyrrhotite, galena, and sphalerite. The effect of grinding, pH, and the presence of xanthate was studied. Metal ion transfer between sulphide minerals was determined. Metal ion production with minerals in pairs was different from that for single minerals. The amount of metal ion in solution followed a galvanic interaction model, increasing for the anodic mineral and decreasing for the cathodic mineral. However, from the EDTA extraction technique, the concentration of …  Lire la suite

It is the aim of Part I of this thesis, the Introduction, to introduce David Zvi Hoffmann (1843-1921) in his capacity of a Bible scholar and a critic of 19th century German biblical criticism. Ample attention will be devoted to Hoffmann's own background, his German environment as well as that of Wellhausen. This will cover Sections I and III of the Introduction respectively. In order to be able to place Hoffmann's work within the proper context, Section II of the Introduction will explore the history of the general critical reception of the Hebrew Bible in the various cultures and eras …  Lire la suite

This thesis describes experiments on granular flow from a flat-bottomed bin with an attached standpipe. The experiments focused on three key aspects of standpipe-flow: (i) the effect of length-to-diameter ratio (L/D) on the mass flow rate and interstitial air pressure distribution, (ii) the effect of surcharge on the flow rate, and (iii) the effects of apparatus grounding and electrostatic charges on flow characteristics. Two materials (coarse sand and fine glass beads) were tested in both the loose and dense flow regimes. In general, experimental data correlated well with previous experimental work, but not with theoretical predictions. Theoretical predictions of the …  Lire la suite

CDKN2A/p16 is a cell cycle inhibitor which blocks abnormal cell growth and proliferation. The CDKN2A gene is frequently mutated or deleted in a wide variety of tumour types. Germline mutations have also been identified in familial atypical multiple mole melanoma (FAMMM) pedigrees. However, the role of CDKN2A in hereditary cancer is uncertain. To explore the relationship between CDKN2A germline mutations and risk of cancer, 75 families with cancers at multiple sites were analysed for germline mutations in the CDKN2A gene. A Met53Ile mutation was found in a non-FAMMM kindred with multiple cancers, including one case of melanoma. The Met53Ile mutation …  Lire la suite

In 1917, a mere thirty years before India gained independence from Britain, Indians were alIowed into the officer corps of the colonial Indian Army, thus initiating its " Indianization ". Yet, as an issue of British military policy, Indianization had been debated for a hundred years before 1917. This thesis delineates the contours of that debate, the myriad schemes for Indianization that it engendered, the reasons for the faHure of each of these, as weIl as the reasons why the bar on Indians in the Indian Army's officer corps was finally broken. In analysing the debate, attention will be paid …  Lire la suite

A field survey was conducted in eight villages in Northeastern Thailand to examine the impact of non-farm employment on rice production during the 1994-95 crop year. This study uses the human ecology approach based on the conceptual framework of Duncan's (1959) ecological complex. This study found that participation in non-farm employment directly affects whether the household will produce rice, but its impacts vary according to the extent of participation. Full-time employment, particularly with the yearlong absence of the male head of household, appears to inhibit rice production because it has the potential to cause a critical farm labor shortage. Part-time …  Lire la suite

The response of Arabidopsis thaliana (Columbia) to infection with turnip mosaic virus (TuMV) was characterized at the level of: disease symptom expression, cell content and protein composition. Visual symptoms observed were chlorotic and mottled leaf colouring, severely stunted growth, distortion of leaf blades and delayed bolting. All plants died before seed cases dehisced. Electron microscopy revealed three types of cylindrical inclusion bodies: pinwheels, scrolls and laminated aggregates, in the cytoplasm of infected plants similar to those observed in other plants infected with TuMV. Inoculation of Arabidopsis with TuMV resulted in quantitative changes in several proteins in both soluble and membrane …  Lire la suite

This study examined the prevalence of information epidemics in the physics literature. The primary interest was to find out whether outliers observed on time series charts of literatures are due to information epidemics, whether these epidemics are widespread occurrences in physics, whether literatures showing such rapid growth arise mainly due to the influence of an important work and, if so, what characterizes these literatures. Information epidemics were defined as spurts of growth in the literature of a field that reflect a sudden excitement and increase in activity. It was hypothesized that information epidemics are common occurrences in the growth of …  Lire la suite

This thesis examines the constitutional guarantee of freedom of expression as applied to electronic mass media. It compares the different approaches adopted in Germany, the United States and Canada. After an overview of freedom of expression doctrine in general and the main features of the regulation of electronic mass media the rationalization of this regulation in freedom of expression doctrine is analyzed. The focus of this analysis is how electronic mass media have changed the traditional understanding of fundamental rights and freedoms as purely negative individual guarantees. This change occasions and necessitates a closer look at governmental regulation and the …  Lire la suite

In this study, light and electron microscopic quantitative analyses were used to examine whether exogenous nerve growth factor (NGF) and/or monosialoganglioside GM1 treatment could affect non-cholinergic systems in the neocortex of the adult rat brain after a devascularising lesion. The two neuronal systems I looked at were the extrinsic noradrenergic and intrinsic somatostatinergic systems. Immediately after unilateral vascular decortication, adult rats received for seven days, via minipump, vehicle, NGF (12 $ mu$g/day) and/or GM1 (1.5 mg/day) into the cerebroventricular space. Thirty days after the lesion, the animals were perfused with histological fixatives, the brains removed and relevant sections processed for …  Lire la suite

This study examined instructional strategies and their impacts on preservice teachers' attitude toward multicultural issues and learners. A qualitative phenomenological approach is used for this study because of my philosophical belief in multiple realities. The research site was a classroom of the Multi-Cultured/Multi-Racial course offered by the Faculty of Education in an English University located in the Montreal area. The studied course was a compulsory preservice teacher training course implemented for the first time in response to the requirement of the Ministry of Education in Quebec. The data were gathered through classroom observation, questionnaires distributed to preservice teachers in the …  Lire la suite

A new testing paradigm called Built-In Self-Test (BIST) has been gaining increasing acceptance over the traditional automatic test pattern generation for testing the current complex integrated circuits. The basic idea in BIST is to integrate the design with test functionalities like pattern generation, response analysis, and test control. Of the various schemes, pseudo-random pattern testing is an attractive technique for BIST because of the simple hardware required for on-chip test pattern generation. Besides, structures for pseudo-random pattern generation like linear feedback shift register (LFSR) or cellular automata (CA) can also be utilized for on-chip response analysis. In general, pseudo-random BIST …  Lire la suite

Two perceived limitations of conventional atomic spectrometry were addressed in these studies. One limitation is that the time required for sample preparation can exceed the actual analysis time by two or more orders of magnitude. High pressure homogenization in combination with high speed blending was evaluated for the preparation of slurries which could be directly analyzed by graphite furnace atomic absorption spectrometry (GF-AAS). Cadmium, copper and lead concentrations were successfully determined in certified reference materials (CRMs) of biological origin and frozen cervine liver and kidney. By capping the flat valve head of the homogenizer with a ruby disc, metal contamination …  Lire la suite

The accidental, or maybe not so accidental, equation of the Long $ rm lbrack TE rbrack$ with the dragon is a minor, yet in many ways symbolic, incident in Western European reinvention of China. This reinvention can be found in a wide variety of discourses, the authors of which range from Enlightenment philosophes to nineteenth-century political economists, to the recent Derrida, and from the even earlier Sir John Mandeville, Oliver Goldsmith, to Coleridge, to W. S. Landor and De Quincey. It covers all aspects of Chinese culture, including philosophy, religion, government, language, poetry, and folklore. This dissertation argues that the …  Lire la suite

This study examines the concept of art education known as Discipline-based art education, (DBAE), from three vantage points. It begins by tracing the history and development of DBAE theory, and by examining its defining characteristics. It follows with a critical discussion of DBAE theory, specifically from within the context of multicultural education. The discussion then shifts to the realm of practice. The study describes a two week professional development program offered by the Minnesota DBAE Consortium, in Minneapolis, in the summer of 1995, and grounds the discussion in the results of questionnaires and interviews with six secondary school art specialists …  Lire la suite

This thesis has focused on the measurement of gas holdup in flotation systems, a variable not measured reliably to date. A sensor was designed using so-called flow conductivity cells. Their properties were studied and modelled, and their application in the design, construction, and operation of a gas holdup probe for use in flotation systems described. A flow cell is defined as one that allows a fluid or dispersion to flow through freely while the electrical conductivity is measured. One of the most important features of a flow cell is the so-called cell constant. Once the cell constant is determined, the …  Lire la suite

In Quebec, between 1914 and 1939, women were portrayed as keepers of the hearth, roles established since the mid-19th century, and further reinforced in the early 20th century when the Western World was threatened with drops in population, high infant mortality and the general ill-health of society. French Canadian physicians were one of the self-proclaimed leaders and experts who maintained they possessed all the knowledge to cure society's ills. Their attention fell principally on the elimination of infant mortality on the one hand, and the promotion of multiple births on the other. To succeed, physicians maintained that while they held …  Lire la suite

The formalin model of inflammatory pain assesses the behavioural response to an injection of dilute formalin into the paw of a rodent. In adult rats, the behavioural response is related to the log of the formalin concentration. Very brief pain responses can be produced by injection of inflammatory mediators, and combination of 5-HT with other mediators produces a synergistic increase in the response. The present study has two aims: (1) to determine the behavioural indices that best measure formalin-induced pain in 3 and 15 day old rat pups, and (2) to examine the behavioural response of infant rats to intraplantar …  Lire la suite

The E1A gene of human adenoviruses induces DNA synthesis but is only able to transform primary rodent cells abortively. Stable transformation is induced by E1A in combination with the E1B gene or another oncogene such as activated Ras. E1B encodes two major proteins, 55K and 19K that are each able to transform cells in cooperation with E1A but with greater efficiency when both are present. The E1B-19K protein is believed to function in a manner homologous to the Bcl-2 proto-oncogene by preventing apoptosis which is induced by the E1A proteins. The E1B-55K protein binds to the p53 tumour suppressor and …  Lire la suite

Zebra mussels (Dreissena polymorpha) have invaded a great proportion of the waters of the eastern part of North America. This mollusk may be a useful sentinel species for bioaccumulation of heavy metals and organic contaminants in aquatic ecosystems. The zebra mussel's capacity to bioaccumulate cadmium at environmentally relevant exposure and to sequester metals in metal-binding proteins, metallothioneins, was investigated. Elevated (relative to control) concentrations of Cd$ sp{2+}$ were detected in Dreissena exposed to $ ge$2 $ mu$g Cd/liter suggesting that zebra mussels cannot regulate Cd$ sp{2+}$ of trace exposure concentration. More than 85% of the measured Cd$ sp{2+}$ was bound …  Lire la suite

The problem of estimating call blocking probabilities in ATM networks is addressed in this thesis. We develop a new, two-step iterated framework for call acceptance control (CAC). In the first step, we define a new variable bit rate (VBR) traffic descriptor called effective rate and we use a known effective bandwidth technique in the second step to estimate cell loss. This approach yields decoupled estimators at the call level so that loss systems models can be used to perform network analysis. Our work on loss systems is divided in three parts: single-link problems, reservation and network problems. In the single-link …  Lire la suite

The diophantine equation sp2 + y sp3 = z sp5 eqno(1) as an infinite number of integer solutions with gcd(x,y,z) = 1. Call (F, G, H) a parametrised solutions of (1) if F, G, and H are non-trivial homogeneous polynomials in Q (s, t) with gcd(F, G, H) = 1 and $F(s, t) sp2 + G(s, t) sp3 = H(s, t) sp5$ for all s, t $ in$ Z. The integer solutions of (1) may be written as a disjoint union of parametrised solutions. A theorem of Beukers states that the number N of such parametrised solutions is finite. However, …  Lire la suite