McGill University Thèses et mémoires publiés en 1988

Natural Killer (NK) cells are able to recognize and lyse tumor cells without prior immunization or sensitization. The initial events leading to target cell lysis by NK cells involves a poorly defined recognition and binding phase. It has been hypothesized however that human NK cells may recognize transferrin receptors as target structures on tumor cells. To determine the possible involvement of transferrin receptors in human NK cell specificity, a correlation study between transferrin receptor expression and competitive activity for NK cell mediated lysis was undertaken. We have determined that the level of transferrin receptors expressed by different populations of K562 …  Lire la suite

This research consisted of three individual studies, examining intra- and inter-modal haptic and visual processing in able learners and reading disabled children spanning the elementary school grades. Performance was measured in terms of: accuracy scores, haptic exploration scores, and exploration times. Higher scores were obtained on the intra-modal visual condition than on any of the conditions involving a haptic component. Increasing the exploration times for haptic stimuli did not significantly improve performance on tasks involving a haptic component. Performance scores of poor readers were depressed on all tasks, suggesting a general deficit in sensory processing rather than an inter-sensory processing …  Lire la suite

"Des expériences ont été entreprises pour déterminer le temps de congélation d'un petit aliment ayant la forme d'un parallépipède rectangle sous des conditions semblables à celles employées par l'industrie. Ce temps de congélation expérimental fut comparé aux temps de congélation obtenus à l'aide de modèles J mathématiques existants. La pomme de terre frite fut choisie , pour ces expériences. Les propriétés thermophysiques des pommes de terre frites nécessaires pour le calcul du temps de : congélation ont été déterminées. La comparaison des résultats expérimentaux et calcu.lés a démontré que les modèles de calcul du temps de congélation ne pouvaient pas …  Lire la suite

It is the purpose of this thesis to examine the development of the concepts of abstraction and formalism in the art theory of Paul Klee and their consequent effect on his artistic production. The major impetus suggested for this development are the writings of Wilhelm Worringer, although the aesthetics of the Munich avant garde must also be credited. I have traced the evolution of Klee's thought through an examination of his diaries, letters and other documents of the period. It is clear that a demonstrable change occurs in Klee's concept of art as a result of his exposure to Worringer …  Lire la suite

Why do people tell stories? Whether it be the oft repeated, endlessly varied fairy tales passed from one generation to the next, the carefully patterned and strictly worded epics of the ancients or tall-tales told around the kitchen table, people have been telling stories to themselves or others since the day someone uttered the first words ever heard on this planet. In the following essay story-telling is called narrativity and is discussed as a function of the desire to impose meaning on experience. The six stories of Drawing the Reader In are about story-telling and how people fail or succeed …  Lire la suite

This study analyses the diffusion of numerically controlled machine tools in sixty Quebec and Ontario engineering and metalworking firms. Interviews with production management provide the data for a critical evaluation of labour process analysis and economic diffusion theory. Management decisions to adopt numerical control technology are found to be guided by technical criteria, contrary to labour process theory. However, economic diffusion theory is found to underestimate the extent of imperfections of knowledge of new technology in industry, the length and costs of learning to use new technology, the complexity of technological evolution, and the diversity of applications and methods of …  Lire la suite

Crawford, John E. (Supervisor)  Lire la suite

The lack of axonal regeneration in the adult mammalian CNS has been correlated with the apparent inability of these neurons to increase their expression of the growth associated protein, GAP-43 in response to injury. Here are reported studies of the expression of GAP-43, in retinal ganglion cells (RGCs) of the adult rat whose axons were cut at different distances along the optic nerve or cut immediately behind the eye and allowed to regenerate along peripheral nerve grafts. The immunocytochemical and axonal transport studies demonstrate that injured and regenerating RGCs synthesize and transport increased levels of GAP-43. The enhanced GAP-43 immunoreactivity …  Lire la suite

Whereas the double-membrane-limited chloroplasts of red and green algae and higher plants are believed to have evolved from endosymbiotic photosynthetic prokaryotes, the quadruple-membrane-bound chloroplasts characteristic of some algal classes may have originated from photosynthetic eukaryotic endosymbionts. The chloroplast compartments of two such algal groups, the Cryptophyceae and Chlorarachniophyceae, contain organelles called nucleomorphs which are postulated to be the vestigial nuclei of these endosymbionts. The demonstration of DNase-sensitive 4$ sp prime$-6-diamidino-2-phenylindole fluorescence and DNA-like fibrils in the nucleomorphs strongly support this hypothesis. Cryptomonads and red algae, the proposed ancestors of cryptomonad chloroplasts, contain phycobiliprotein pigments. Although immunological and amino acid sequencing …  Lire la suite

In response to i.v. ANF at 175 ng/kg/min, normal dogs increase sodium excretion ($ Delta$UNaV = 150 uEq/min) independent of changes in GFR and RPF. In contrast, when ANF was infused into chronic caval dogs (TIVC) or cirrhotic dogs (Cir) retaining sodium in the presence of ascites, they divided 50:50 into those who had a marked natriuretic response (responders, R) and those who had no natriuretic response (non-responders, NR). Of 46 TIVC dogs, 22 R had UnaV of 185 + 35 uEq/min and 24 NR had $ Delta$UNaV = 2 + 1 uEq/min. In 19 Cir dogs, 9 R had …  Lire la suite

Aspects of stability of access tunnels with particular reference to the factors controlling face access tunnel closure upon the efficiency of coal production and safety of longwall mining operations are investigated. These are used to justify the present studies of tunnel stability and barrier pillar design in mines of the Cape Breton Coalfield. An analysis of in situ deformation data of 26 face access tunnels by tunnel convergence measurement and a new photographic technique for approximately 40 km of tunnels are presented. Comparative studies of these techniques are made and deformation characteristics with respect to depth of cover, panel width, …  Lire la suite

Yeats's depiction of political violence is examined through a reading of the political poetry centred on "Easter 1916," "Nineteen Hundred and Nineteen," and "Meditations in Time of Civil War," each of these bearing a title emphasizing the poem's historicality, each representing one of the violent epochs in modern Ireland. By studying the dramatized narrative persona utilized by Yeats--a persona constituting the ideological and societal contexts of the poem, and effecting, through the choice of perspective, the selection of historical materials--the particular contents of Yeats's history-making are brought into focus. Yeats was both a romantic poet uneasy with the political component …  Lire la suite

The tonoplast H$ sp+$-ATPase of Beta vulgaris L. was partially purified by Triton X-100 solubilization and Sepharose 4B chromatography resulting in the enrichment of two polypeptides (57 and 67 kDa). Kinetic analysis of ($ alpha$-$ sp{32}$P) BzATP labeling identified the 57 kDa polypeptide as a nucleotide-binding subunit with a possible regulatory function. In addition, ($ sp{14}$C) DCCD-labeling identified a 16 kDa polypeptide as a putative transmembrane proton channel. It is concluded that the tonoplast H$ sp+$-ATPase is a multimer composed of at least three polypeptides. Anti-57 and anti-67 kDa sera reacted with polypeptides of the corresponding size in bovine chromaffin …  Lire la suite

The trend towards family care of children with developmental disabilities has lead us to examine ways to support families. One source of help primary caregivers have available to them is informal social support. Ninety mothers of children with severe developmental disabilities, residing in four Michigan counties (two urban and two rural) were interviewed face-to-face to determine the nature and extent of their informal social support systems. The types of support investigated were perceived, instrumental, emotional, informational and network. Data were analyzed using bivariate and multivariate techniques. The findings indicate that mothers are primarily responsible for the day-to-day care of their …  Lire la suite

The nature of truth has occupied philosophers since the very beginning of the field. Our goal is to clarify the notion of scientific truth, in particular the notion of partial truth of facts. Our strategy consists to brake the problem into smaller, more manageable, questions. Thus, we distinguish the truth of a scientific theory, what we call the "global" truth value of a theory, from the truth of a particular scientific proposition, what we call the "local" truth values of a theory. We will present a new local theory of partial truth and will have few things to say about …  Lire la suite

Measles virus is an animal enveloped virus that is a member of the genus morbillivirus in the paramyxoviridae family. Its envelope contains two surface glycoproteins H and F which are required for viral attachment and entry respectively. Virus penetration occurs via a process which involves fusion of the viral membrane with the plasma membrane at the cell surface. Replication of the virus thus follows and leads to giant cell (syncytia) formation. The infectivity of measles virus is dependent upon a host proteolytic cleavage of the F$ sb0$ glycoprotein into two active subunits F$ sb1$ and F$ sb2$. This cleavage was …  Lire la suite

The conventional approach in the theory and econometrics of investment is the partition of gross capital investment in two components: expansion (or net) investment and replacement investment. This thesis examines the latter component. A critical assessment of the literature and the empirical evidence reveal that the prevailing view of replacement known as the "proportional replacement hypothesis" is incorrectly specified and unsatisfactory. This thesis examines a variety of data brought together under the same focus for the first time and comes up with two important findings. First, firms maintain the operating capacity of their equipment not by replacing the whole of …  Lire la suite

Graft versus host disease (GVHD) is a major complication of bone marrow transplantation and may also occur naturally through the transplacental passage of maternal lymphocytes to the fetus. GVHD is associated with a broad spectrum of immunological disorders as well as distinct pathological changes. Yet, the exact nature of the effector cells involved remains to be elucidated. Studies on natural killer cell activity in bone marrow transplant patients have led to the speculation that natural killer cells may be major effectors of GVHD-induced immunopathogenesis. To determine the role played by natural killer cells in GVHD, a murine model of neonatal …  Lire la suite

This study presents methodology for technical and economic performance analysis of conventional grinding circuits supported by two industrial cases. A review of the strengths and weaknesses of Bond work index and population balance modelling approaches to plant circuit analysis discloses the need to refine work index determinations, and to establish a system of more meaningful ball mill circuit performance parameters. The statistical reliability of carefully determined rod mill work index efficiency ratings is presented. Technical and economic performance improvements through rod mill speed and feed water rate adjustments are presented. Parameters which separately characterize overall ball mill circuit classification and …  Lire la suite

Interactions among stationary planetary waves in the winter stratosphere are studied using steady-state quasi-geostrophic models from both a theoretical and numerical point of view. A triad of small amplitude waves is examined analytically using a constant zonal wind $ beta$-plane model in which dissipation is required for the waves to interact. The nature of the modifications to the linear solutions is found to depend both on the propagation characteristics and the zonal wavenumber of the modes. Numerical solutions are determined using a climatological basic state and boundary forcing. The changes to the linear structure are relatively weak. Zonal wavenumber 1 …  Lire la suite