McGill University Thèses et mémoires publiés en 1989

The purposes of this thesis are to examine experimental results obtained with subsurface irrigation of maize in 1988, and to provide preliminary plans and an economic analysis for the subsurface irrigation of maize in Richelieu County, Quebec. A mean increase in maize yield of 3.7 % was observed in 1988 on experimental plots with subsurface irrigation at the Charbonneau farm. However, a review of results obtained at the same experimental site from 1982 to 1988 indicated that the mean increase in maize yield with subsurface irrigation was 29 %. Plans for two possible water supply systems designed to provide 180 …  Lire la suite

The partition of surfactants and of a biosurfactant-producing microorganism was studied in polyethylene glycol and dextran aqueous two-phase systems. In the presence of sodium phosphate, surfactants distributed themselves according to their charge. Cationic surfactants preferred the bottom phase, while anionic surfactants were attracted to the top phase. Increasing the phosphate molarity, the pH, the polymer concentration or molecular weight all resulted in a more one-sided surfactant partitioning. Biosurfactant partition was weaker than synthetic surfactant partition due to their weaker effective charge and lack of strong specific affinity for one of the polymers. Bacillus subtilis cells partitioned very strongly to the …  Lire la suite

Octahedral cobalt complexes of the type cis- ((N$ sb4)$Co(OH)(OH$ sb2)$) $ sp{2+}$ where N$ sb4$ represents a tetraamine ligand, are highly efficient at hydrolyzing phosphate diesters. Furthermore the reactivity of the cobalt complexes is very sensitive to the tetraamine ligand structure. In the first part of this work, crystal structures of some key cobalt complexes have been determined. Close examination reveals an interesting structure-reactivity relationship. In the second part of this work, existing MMX force field is evaluated for predicting the structures of cobalt complexes. A modification of the force field was necessary in order to obtain good correlation between …  Lire la suite

A comparative diagnostic study of upper-air persistent atmospheric events, as simulated by a general circulation model (GCM) and as observed, is presented. We start with an overview of the several theories that attempt to explain such phenomena. Particular emphasis is put on the model approach of Shutts (1983). We next show that the spatial distributions of persistent events is qualitatively similar in the GCM and observational data. The North-Atlantic events are extracted and a rotated empirical orthogonal function (REOF) analysis is done on the resulting data sets. The two REOF sets that are thus obtained are shown to greatly resemble …  Lire la suite

The processing conditions for carbothermal reduction of silica to silicon nitride was found to be sensitive to several key processing parameters: namely the intimacy of mixing of carbon and silica, the temperature, the specific high surface area of carbon, the nitrogen gas purity and the action of the nitrogen gas passing through the reactants. Sol-gel processing was found to provide superior mixing conditions over dry mixing, which allowed for complete conversion to silicon nitride at optimum carbon:silica ratios of 7:1. The ideal reaction temperature was found to be in the range of 1500$ sp circ$C to 1550$ sp circ$C. Suppression …  Lire la suite

The Golgi apparatus is organized into a characteristic differentiated stack in all eukaryotic cells. During mitosis, the Golgi apparatus disassembles into smaller clustered vesicles lacking recognizable cisternae whereupon they recombine to form typical stacks in each of the daughter cells (Lucocq et al., 1987). Paiment et al. (1989) have demonstrated that dispersed (unstacked) Golgi fragments will reconstitute into a functional stacked Golgi apparatus when microinjected into Xenopus laevis oocytes. Disrupted hepatic Golgi fractions (Gi) were isolated on discontinuous sucrose gradients and incubated at 37$ sp circ$C in the presence or absence of calf brain cytosol, ATP, and GTP$ gamma$S with …  Lire la suite

In this thesis, the effect of geometrical roughness of a non-deformable road surface on the mobility performance of a pneumatic tyre is investigated. A system function which represents the theoretical relationship between the drawbar-pull and the random traction surface geometry is developed in the frequency domain, associated with the energy conservation law. Prior to the analysis, measurement of road profile is achieved using an ultrasonic distance detector, and characterization of the stochastic road profile is evaluated by a power spectral density function. Further to this, the resulting drawbar-pull and tractive efficiency for a given slip rate, applied torque, tyre characteristics …  Lire la suite

Gas phase axial dispersion for gas-liquid countercurrent contacting in mobile bed contacting (MBC) and in a spray column were measured for 240 combinations of five variables, gas and liquid flow rate, packing size and density and static bed height, for MBC; for 114 combinations of three variables, gas and liquid flow rate and static bed height, for the spray contactor. The experimental technique was dynamic response to a tracer, coupled with moment equations for the system in axially dispersed plug flow (ADPF). The ADPF model was found to represent well the residence time distribution curves for all experiments with both …  Lire la suite

The prediction of mean end-to-end delay of multiple packet messages is the focus of this thesis. The models established are of great importance to network designers as they provide the basis for meeting user requirements for time delays and for network throughput. Two distinct models are developed depending upon the traffic load requested by network users. The first model considers traffic conditions in which the traffic demand heavily loads the computer network. Mean end-to-end message delays are computed by assuming the existence of product form solution of the obtained closed queueing network model. Heuristics are developed and are validated via …  Lire la suite

This thesis presents an implementation of supervised learning performed with a stochastic neural net, as applied to a classification of business firms based on financial statements and ratios. The general Boltzmann Machine Algorithm is presented in detail, as well as the specific version designed for this application. We describe in detail several classifications that we attempted to reproduce, and some of the different possible ways of encoding the data issued from the income statements and the balance sheet. The results are shown to depend on the chosen encoding. We also confirm that the neural net behaves better when it is …  Lire la suite

Dietary carbohydrate during pregnancy is essential but whether this requirement is specific to glucose or if fructose could substitute for glucose in the diet of pregnant rat dams was investigated. It was concluded that the carbohydrate requirement for the rat during pregnancy is not specific to glucose and the level, not the type, of carbohydrate was critical. The potential toxicity of high fructose diets was also investigated. Dams fed high fructose had significantly higher liver weights than dams fed high glucose while other toxic indicators were not affected. A third aspect was the comparison of isocaloric, low carbohydrate diets containing …  Lire la suite

Transcription in mammalian and yeast mitochondria proceeds from a few well defined promoters, with processing of polycistronic transcripts producing the mature RNAs. The levels of different sequences in the steady-state RNA populations depend on differential promoter strengths, transcription attenuation and/or selective termination, and differential RNA stabilities. To gain insights into the processes governing transcription and RNA levels in plant mitochondria, a system using isolated maize mitochondria, which synthesize bona fide mitochondrial RNAs, was developed and partially characterized with respect to exogenous requirements and sensitivity to inhibitors of DNA-dependent RNA synthesis. Although initiation and processing probably occur at reduced levels in …  Lire la suite

This study was an attempt to combine both the psychological and lifestyles approaches and use qualitative research techniques in order to explore how young anglophones living in Montreal adapted to prolonged periods of unemployment. I examined how these young people felt their well-being was influenced by the experience of unemployment, what factors distinguished those who coped well with unemployment from those whose well-being declined, and how the mental health of respondents influenced their ability to adapt their lifestyle to accommodate prolonged periods of unemployment. This study provides detailed data about young people's subjective experience of unemployment and indicates the means …  Lire la suite

The thesis examines the Canadian policy and law affecting those services sectors affected by the provisions of the Canada - U.S. Free Trade Agreement which relate to telecommunications, enhanced network services, and computer/information services. In particular, constitutional law and administrative law in telecommunications matters are examined. Also examined in detail are those provisions of the Free Trade Agreement which affect the regulatory measures relating to the telecommunications transport sector and regulatory measures relating to other services which extensively utilize telecommunications, computer and information services.  Lire la suite

The x-ray total structure factor of the glassy-metal alloys $Mg sb{70}Zn sb{30}, Ca sb{70}Mg sb{30}$ and $Mg sb{85.5}Cu sb{14.5}$ has been measured at three temperatures: 9K, 150K, and 300K. The data have a statistical precision of about.8% and an absolute accuracy of roughly 3%. Percus-Yevick hard sphere structure factors may be fitted quite accurately to the data in the region of the first peak. In addition, the variation of the experimental structure factor with composition is found to be consistent with the Percus-Yevick theory. At low k values, Percus-Yevick and other theoretical model structure factors are in poor agreement with …  Lire la suite

"Azospirillum lipoferum and A. amazonense showed significant uptake-hydrogenase CH2 uptake) activities under N2 -fixing condition. The NH4Cl-grown cultures of both species showed negligible activities. However, sparging with H2 during growth caused over a 100-fold induction of uptakehydrogenase activities, suggesting that hydrogenase synthesis requires exogenous H2 as an inducer. Oxygen-dependent uptakehydrogenase activity in A. amazonense was very tolerant to Ü2 and almost unaffected by 20 kPa 02 in vivo, whereas in A. lipoferum and A. brasilense the activities were inhibited by 40 and 100%, respectively. In cell-free extracts (CFE), the uptake hydrogenase of A. amazonense was still 02 tolerant and the …  Lire la suite

The rule-following problem can be condensed into the paradox that a rule cannot determine any course of action because every course of action can be made to accord with that rule. In his Wittgenstein on Rules and Private Language, Saul Kripke sees this paradox as potentially leading to a radical semantic scepticism that renders meaning itself meaningless, and attributes a sceptical solution of the problem to Wittgenstein. After a critical examination of Kripke's work, I conclude that this solution fails on account of allowing neither for a normativity beyond the subjection of the individual to correction by others in her …  Lire la suite

An off-line method of tuning PID controllers used in process control applications is presented. The plant under consideration is of second order with delay and the loop is presumed to be operating at steady state under the influence of random disturbances. Tuning is performed by minimizing the cost function, namely the integral of squared error, with respect to the tuning parameters. To do this, a second order approximation of the cost function is obtained and minimized using the Newton-Raphson method. System identification is done without interrupting production by introducing test signals of low signal to noise ratio and using a …  Lire la suite

This thesis is the analysis of Annex 18 to the Chicago convention on the Safe Carriage by Air of Dangerous Goods. Chapter one is a throughout analytical history of the international standards on the air carriage of dangerous goods, the influence of IATA and ICAO thereon on their drafting and implementation. Chapter two is on the regulations on the air carriage of dangerous goods in North America, in the United States and Canada, and the influence of Annex 18 thereon. Chapter three talks about the liability involved in the carriage of dangerous goods under common law, civil law, the Warsaw …  Lire la suite

Paidoussis, Michael P. (Supervisor)  Lire la suite

This thesis on literary writing consists of a critic and of a fiction. The critic entitled De la nouvelle au recueil: la singularite d'un genre is the result of a detailed research regarding the literary characteristics of the short story. The last part of the text is devoted to a study on the collection. This essay is followed by the creation Aspirations. This collection contains thirteen stories, of which twelve are moments of quiet cruelty in every day life. The characters in Aspirations attempt to resist silently to the aspiring power of certain events. Most of them keep up struggling …  Lire la suite

The purpose of this thesis is to analyze the relative influence of state and societal actors on public policy and, specifically, to determine the potential for state autonomy in Canada. To advance this project, two 'paradigms' of state-society relations are developed from an analysis of a range of contending theories of state-society relations. These include Eric Nordlinger's state autonomy theory, elitism, pluralism, and Marxism. The paradigms are then applied to a case study of the design and implementation of the petroleum related elements of the National Energy Program. We conclude that the Canadian state can demonstrate a significant degree of …  Lire la suite

Long-term administration of recombinant bovine somatotropin (rbST) significantly increased milk and 3.5% fat-corrected milk production without altering milk composition. These effects occurred regardless of breed, parity or drug delivery system (daily or sustained-release) utilized. Somatotropin did not affect apparent digestibility of rations, dry matter intake, crude protein intake, energy intake or energy balance. Body energy reserves, measured as body condition scores, decreased during rbST treatment resulting, together with the increase in milk yield, in an improvement of the efficiency of conversion of feed to milk for cows treated with rbST. Body condition was completely regained during the dry period. No …  Lire la suite

The model of nuclear dynamics according to the Boltzmann-Uehling-Uhlenbeck (BUU) equation which incorporates fluctuations is presented. This model is employed to calculate heavy-ion reactions in the intermediate energy regime $(20 leq E sb{lab}/A leq 200MeV)$. Using a local (Skyrme-type) interaction, the model is capable of reproducing diverse features of spectator and participant observables. A finite range interaction is introduced to generate diffuse nuclear surfaces in the Vlasov approach. The peripheral reaction of $ sp{40}Ar$ on $ sp{27}Al$ is calculated with this interaction. Characteristic features of the angular distribution of the projectile-like fragments and its correlation with the target-like fragments are …  Lire la suite

The thesis is divided into two parts. In part I, the monomeric and dimeric metal carbonyl complexes, M(CO)$ sb6$ (M = Cr, Mo, W), CpMn(CO)$ sb3$ (Cp = $ eta sp5$-C$ sb5$H$ sb5$), ($ eta sp6$-C$ sb6$H$ sb6$)Cr(CO)$ sb3$, (CpFe(CO)$ sb2$) $ sb2$, (CpMo(CO)$ sb3$) $ sb2$, Mn$ sb2$(CO)$ sb{10}$ and trans-Ir(CO)Cl(PPh$ sb3$)$ sb2$, have been embedded into polystyrene (PS), poly(methylmethacrylate) (PMMA) and poly(styreneacrylonitrile) (PSAN) polymer film matrices. The environments experienced by the metal complexes as a function of the polymer type have been characterized by vibrational spectroscopy and have been compared with those of the structurally-related solvents toluene, ethyl …  Lire la suite