McGill University Thèses et mémoires publiés en 1997

Cystinuria is an autosomal recessive disorder of the kidneys and intestine with defective luminal transport of cystine and other dibasic amino acids (ornithine, arginine, and lysine). Three phenotypes have been described, based on urinary excretion of these amino acids in obligate heterozygotes: Type I (silent carriers); Type II (moderate elevation); and Type III (mild elevation). The SLC3AI (D2H) protein has been shown to enhance cystine reabsorption and mutations in D2H have been reported in cystinuria. The aims of this study were to characterize D2H gene structure and to identify mutations in Quebec patients. The D2H cDNA was used to isolate …  Lire la suite

A large number of behavioural methods have been developed to investigate nociception and the actions of analgesic drugs in animals. The formalin test is increasingly used as a model of injury-produced pain. The generally accepted method of rating pain used for mice is to count or time paw licks. The aim of this study was to examine scoring properties of other behaviours in the formalin test in mice, and determine the best measure of pain. In the first experiment, the behavioural responses to intraplantar injection of a series of formalin concentrations were assessed. In the second experiment a fixed concentration …  Lire la suite

Crepeau, Claude (Supervisor)  Lire la suite

By examining first the life and works of Muhammad ibn Murtada al-Fayd al-Kashani (1007/1598-1091/1680), we hope this will serve as an introduction to some of his viewpoints. We will consider his theories of muraqabat al-nafs (self-supervision) and muhasabat al-nafs (self-accounting) as expounded in his book al-Mahajjah al-Bayda', which was written as a work to enhance Ihya' al-'Ulum by al-Ghazali, (450/1058-505/1111) from a Shi'ah perspective. We will also compare the views of al-Fayd and al-Ghazali as expressed in their respective books. Self-supervision and self-accounting are two main terms of ethical terminology that enjoy a rich history in Islamic philosophy. Al-Fayd's views …  Lire la suite

Previous studies on Al85Yx Ni15-x glasses established a correlation between crystallization mode (pure growth versus nucleation and growth) and crystallization product. Glasses with approximate compositions x = 5, 7, 8, 10 were studied in order to accurately ascertain the nature of the structural variance which gives rise to different crystallization modes and the identity of the resulting crystallization products. Glasses with x = 5, 10 have a clear distinction: x = 5 contains quenched-in Al nanocrystals which act as nucleating centers leading to alpha-Al as the first crystalline product; equilibrium crystalline phases are alpha-Al, Al3Ni and a stacking variation of …  Lire la suite

Gait speed is an ideal measure of locomotor recovery following stroke but its responsiveness and clinical terminants have received little attention. The main objectives of this prospective study were to identify the most responsive clinical measure of gait speed, and to identify predictors of gait speed recovery in the acute phase post-stroke. Fifty clients were evaluated on four tests of gait speed, and other measures of disability and impairment during the first and fifth week following a first-time stroke. Responsiveness was estimated using standardized response mean, and four other indices. Multiple linear regression was used to identify significant predictors of …  Lire la suite

Motivated by Geographical Information Systems (GIS) applications, we introduce a new data model for mutually nested objects. Combining features from relational as well as object-oriented database systems, our data model is efficient for queries involving multiple access patterns. By maintaining symmetrical relationships between entities, we allow nesting to be formulated dynamically at the query level rather than the data model level, thus dissociating the data structure from the access method. In addition, we do not favor one access pattern over another by clustering data in one particular manner, giving therefore flexibility and performance to our system. In order to integrate …  Lire la suite

This Thesis is divided into three parts. First, it discusses the international setting of satellite communications, presenting the diversity of their legal regimes. It then addresses, in two subsequent parts, the two major regulatory markets which are moulding the evolution of the international setting of space-based communications. In a second part, it presents North-America which was the inceptor of the deregulation trend and of the LEO systems and which firmly holds the lead of the regulatory trend. Then, it addresses Western Europe which is attempting to exert a part of the control of the evolution of the LEO lion's share …  Lire la suite

Domestic space is a primary site for cultural reproduction. When the inhabitants intensively interact with domestic space, the house receives its cultural significance. This thesis aims to understand how, through practices, meanings are embodied in the spatial formation of the Javanese house, and how these meanings in return affect the spatiality of certain practices. The subject of these observations are four houses of considerably different scales and forms, which range from a simple single-structure house to the elaborate Sultan's palace. The domestic activities observed encompass three types of activities: daily life, ritual celebrations, and theatrical performances. My study is based …  Lire la suite

This research examined the toxicity of complex industrial effluents as measured by chemical analyses, whole effluent toxicity (WET) tests and surveys of the receiving water biota. Toxicity of final effluents from 45 diverse facilities was examined to determine whether inferred toxicity based on presence and concentration of priority substances could predict WET, calculated from a battery of bioassays on bacteria, cladocerans and algae. Following corrections of inferred toxicity for particle-bound contaminants and adjustment for free ion activity, correlation between inferred and whole effluent toxicity was highly significant. Effluents with elevated metal concentrations exhibited lower WET than predicted, likely due to …  Lire la suite

Serotonin (5-HT) is a neurotransmitter that elicits or modulates a wide variety of physiological processes by interacting with an impressive variety of distinct receptor subtypes widely distributed throughout virtually the whole body. Two of these receptor subtypes, 5-HT2A and 5-HT 2C, have drawn much attention because of their paradoxical regulation and their role in the etiology and treatment of psychiatric disorders such as depression, suicide and schizophrenia. While expression of the 5-HT 2A receptor is widespread throughout the body, expression of the 5-HT 2C receptor is restricted to the brain. To better understand the regulation of receptors at a mechanistic, …  Lire la suite

The traditional model of corporate governance is comprised of three main players: the board of directors, the management, and the shareholders who own of the corporation. This model has received a wave of criticism. The two most important complaints were that the directors had little to do with the day-to-day business of the corporation, and in their decision making the interests of the shareholders were not being taken into account. This situation has led to the creation of what has been called the "expectation gap" which is defined as the gap which exists between the shareholder's expectation, and the performance …  Lire la suite

Data taken with the ARGUS detector at DESY, Hamburg, specifically tt pairs produced from e+e -- collisions in the energy range (10.4--10.6)GeV, are used to make a precision measurement of the tau lifetime. A new method is introduced which is independent of the beam position and envelope, and applicable to tau events having one-three topology. Applied to ARGUS data the method yields a value for the tau lifetime of tt=287+/-11st atistical+/-8systemat icfs.  Lire la suite

Ly-6 molecules are glycosylphosphatidyl inositol (GPI)-anchored cell surface proteins found on hematopoetic cells. Their functions are unknown. Some studies suggest functions in lymphocyte activation while others suggest an involvement in migration or tissue localization. There is also evidence for their participation in intercellular adhesion which is consistent with both of the above functions. Our approach to understanding their function is to identify the molecules with which they interact. Studying primarily Ly-6E, our strategy was to create a soluble form of Ly-6E. This was done using the expression vector pEXV-3 containing an Ly-6E DNA fragment modified to encode the Ly-6E protein …  Lire la suite

The Saguenay Fjord sediments are characterized by high trace metal, organic matter and iron monosulphide (AVS) concentrations. The presence of important maritime activities, as well as dredging operations and natural slumpling events, contribute to the resuspension of the Fjord sediments and changes in their redox conditions. The objective of this research was to determine the impact of sediment resuspension on the remobilization of trace metals (e.g. Hg, Cu, Ni, Pb, As, Fe and Mn). in the water column. Once dissolved in the water column, the trace metals are subjected to a suite of geochemical processes, while remaining available for the …  Lire la suite

The effects of agricultural development on wood turtles (Clemmys insculpta) were investigated in Quebec during 1994 and 1995. Age structures, growth, and mutilation rates were compared between an agricultural population and a reference site in an undisturbed forest. Turtles in the 0-4 year age class were absent from samples taken at the agricultural site. Overall, 23% less juveniles were encountered at the agricultural site. In addition, relatively fewer adults were captured from the 20+ age class. Shell injuries were twice as common at the agricultural site when compared to the forest site; whereas, limb amputations were twice as frequent at …  Lire la suite

This thesis argues that women's bodies are constituted by discourses about them. It explores the operations of power over women's bodies by analyzing the way in which the maternal body is constructed in the discourses of law, medicine and culture. Chapter One provides a theoretical context for this thesis. It examines the organization of knowledge and its relationship to power within the Western liberal tradition. Power is implicated in the production and dissemination of knowledge about the maternal body in two ways. First, scientific knowledge is privileged in legal and cultural discourses with the effect that knowledge claims based on …  Lire la suite

According to Locke and Latham (1990), goal-setting is a powerful motivationa! tool which captivates the individual's attention and sense of effort in pooling all available resources to accomplish a task with accrued determination. Goal-setting has been used successfully in sports and physical activities (Kyllo & Landers, 1995). Positive results have also been realized with low achievers in academic tasks (Bandura & Schunk, 1981). The purpose of this investigation was to test the effects of goal-setting on basketball free throwing with normally achieving (NA) boys and girls, and with children having learning disabilities (LD), ages 9-13 years. This study also tested …  Lire la suite

Novel chimeric oligonucleotides containing L-alpha-dC monomeric units linked in the 3'3' → 5 '5' orientation have been synthesized and binding studies were performed. Thermal denaturation studies done on 7-mer sequences containing either an internal 3'3' L-alpha-dC-5'5' insert or a 3'3'-D-alpha-dC-5 '5' insert in the same position, with their complementary sequence, showed a comparable destabilization of DeltaT m = 6°C and 7°C, respectively in physiological buffer. A 19-mer sequence, complementary to a sequence near the beginning of the 5'LTR region of HIV-1 genomic mRNA, containing six alternating 3'3'-L-alpha-dC-5 '5' inserts was synthesized. Binding studies showed that this novel oligonucleotide formed stable …  Lire la suite

Because of the centrality of Christ, truly God and truly human, Christian theology regards the understanding of the human as one of its essential tasks. In the wake of environmental concerns, however, the dominant self-understanding of the human is presently being challenged and rethought by Christians. This study is an attempt to contribute to this larger effort of examining the role of the human in Christian theological responses to the ecological "crisis," a question that is surfacing as a paramount concern in this emergent literature. In this work I examine how the role of the human is an inherent problematic …  Lire la suite

Baum, Gregory (Supervisor)  Lire la suite

This thesis examines the history of female immigrant domestic labour in Canada from a socialist feminist perspective. Over the past hundred years, Canadian immigration policy with respect to domestic workers became increasingly regressive with the shift in the racial composition of foreign female domestics. The women's movement contributed to this change as gains in Canadian women's public rights did not effectively challenge the dominant social paradigm of women's roles, and so left intact the public-private divide and the sexual division of labour to which were allied biases of race and class. The women's movement thus became an unwitting participant in …  Lire la suite

Previous studies have shown that mortality reduction with thrombolysis in acute myocardial infarction depends in part on time to thrombolysis, which can be shortened by administering these drugs in the Emergency Department (ED). This study was undertaken to determine the appropriateness of thrombolytic use by Emergency Physicians, and to determine complication rates of ED thrombolysis. The charts of 137 patients admitted from a tertiary care hospital ED with acute coronary syndromes were assessed for concordance with standard Canadian thrombolytic guidelines, based on a blinded review by two independent assessors. The adjusted Kappa statistic for the overall concordance with the guidelines …  Lire la suite

Cells of the oligodendrocyte lineage go through a complex sequence of division, migration and differentiation. In transgenic mice in which the first exon of myelin basic protein (MBP) has been replaced with the Lac Z reporter gene, Lac Z expression emerges adjacent to the putative source of the oligodendrocyte lineage, after PDGFaR-expressing progenitors have left the ventricular zone. This suggests transcriptional activity at the MBP locus begins in oligodendrocytes at the premyelinating stage of development. Low-level Lac Z expression is also observed in the presumptive grey matter from embryonic day 12 (E12). In contrast, transgenic mice bearing Lac Z fused …  Lire la suite

Leukotrienes are potent mediators of immediate hypersensitivity reactions and are predominantly produced by myeloid cells. Although the regulatory mechanisms governing leukotriene biosynthesis are largely unknown, cytokines have been shown to upregulate leukotriene production by these cells. GM-CSF primed leukotriene biosynthesis in a dose-dependent manner in eosinophilic HL-60 cells, whereas IL-5 had no effect on leukotriene production in this cell line. GM-CSF did not affect the kinetic parameters of LTC4 synthase and therefore most likely enhanced the rate of leukotriene biosynthesis by acting upstream of this catalytic event in the biosynthetic pathway. This differential priming ability was not merely due to …  Lire la suite

Family and Community Medicine was introduced to Costa Rica through the McGill-CENDEISSS Project of 1989-1994. The development of this new speciality is interpreted as a "professionalization" drive, which, while appropriating the discourse of the international primary health care movement, in fact places more importance, as a social movement, on negotiating for and expanding its own jurisdictional space. Two bodies of literature are called upon to provide theoretical guidance, namely, writing on "professionalization" and ethnographic interpretations of "development" in the so-called Third World. The phenomenon of Family and Community Medicine in Costa Rica is described as an international, national, and local …  Lire la suite

This thesis examines the possibility of increasing the speed of Near-Field measurement of an Antenna, by reducing the number of measurement points and by determining the degree of truncation permissible while maintaining a prescribed degree of precision of the reconstructed far-field. The mathematical formulation leading to the near-field to far-field transform is presented in a novel and simpler form to use. Relations are established between the selected area and sampling rate of Near-Field measurement and the accuracy of the Far-Field of an Antenna. The spectral domain of the field is analysed in each case and parametric curves are derived. Correction …  Lire la suite

Peterson, P. R. (Supervisor)  Lire la suite

Activation of GABA$ rm sb{B}$ receptors inhibits spontaneous and evoked neuronal activity in different regions of the central nervous system, including the nucleus tractus solitarius (NTS), the projection site of pulmonary vagal afferent fibres. These studies were designed to test the hypothesis that GABA$ rm sb{B}$ receptors in the NTS modulate the vagally mediated cardiorespiratory reflexes. Experiments were conducted on 53 spontaneously breathing, urethane-anesthetized (1.2-1.6 g/kg) and atropinized (0.2 mg/kg) rats. Tracheal pressure, tidal volume, mean arterial blood pressure, and the integrated diaphragmatic electromyogram (DiEMG) were recorded. The medulla was prepared for bilateral NTS injection of 110 nl of saline …  Lire la suite

Extensive in vitro and in vivo studies indicate that one important biological function of the embryo-specific glycoprotein alpha-fetoprotein (AFP) is to down regulate certain T cell responses in order to control potentially harmful autoreactive events during fetal development. However, there are some reports which contend that AFP-mediated immunosuppression is not an inherent property of the molecule itself, but is instead, hypothesized to be either a function of a low molecular weight inhibitor bound to AFP or to a post-translational modification of the protein. To resolve these issues, the present thesis examines the possible contributory roles of endogenous and exogenous ligands, …  Lire la suite

This study examines the cholera epidemic in Montreal during the summer of 1832, focusing on the Montreal Board of Health, the public health regulations, medical involvement on the Board, and the voluntary movement. Using newspapers, judicial documents, and correspondence, it seeks to re-examine the epidemic to further the understanding of the modernization of the Canadian state in the area of public health. Many of the histories concerning the modernization of the Lower Canadian state have focussed on the 1837 rebellions as a breaking point between the 'old' state and the 'modern' state. If modernization can be equated with the process …  Lire la suite

The phenyl phosphate monoester in (Co$ sb2$(bpmp)($ mu$-PP)(OH)(OH$ sb2$)) (ClO$ sb4) sb2$ is hydrolyzed an unprecedented 10$ sp{11}$ times more rapidly than the corresponding unbound phosphate. Clean conversion of the bidentate monoester ((Co$ sb2$(bpmp)($ mu$-PP)(OH) (OH$ sb2$)) (ClO$ sb4) sb2$) to the tridentate inorganic phosphate ((Co$ sb2$(bpmp)($ mu, mu sp2$-Pi) (OH)) (ClO$ sb4$)), together with the crystal structure of an analog of phenylphosphonate, (Co$ sb2$(bpmp)($ mu$-PPO3)(OH)(OH$ sb2$)) (ClO$ sb4) sb2$ provide detailed mechanistic insight into the hydrolysis reaction. The structure of (Co$ sb2$(bpmp)($ mu$-DPPO2)($ mu$-O$ sb2$)) (ClO$ sb4) sb2$ contains a diphenylphosphinate and a peroxide bridged between two cobalt(III) centers. …  Lire la suite

This thesis presents a method for synthesizing highly realistic-looking clouds. This method produces a complete 3-dimensional model of a cloud so that an image can be synthesized from any viewing direction so long as the camera is above the cloud. We take a satellite image of a cloud or cloud field (which is a scene of several clouds), along with a height field for the scene and construct a cloud model which could have produced the input picture. This approach combines several image synthesis techniques, such as the construction and rendering of parametric bicubic surfaces, texture mapping, and transparency effects. …  Lire la suite

Interleukin-2 (IL-2), an immunomodulatory cytokine first isolated from the immune system, plays an essential role in the maturation of T lymphocytes. This thesis focusses on the neuroanatomical features of IL-2 and IL-2 receptors in the central nervous system, the neuromodulatory role of IL-2 on hippocampal acetylcholine release, and possible intracellular signalling mechanisms following IL-2 receptor activation in the brain. Using immunoautoradiography, IL-2-like immunoreactivities were observed in a selected pattern in the central nervous system, with particularly high densities seen in the hippocampal formation and the hypothalamus of the rodent brain. The cellular localisation of the immunostaining using immunohistochemical approaches reveals …  Lire la suite

This numerical modeling study consists of two main parts. The first part is related to the simulation of industrial scale continuous slab casting systems, while the second part deals with the simulation of a twin-roll thin-strip casting process. In the first part, a numerical investigation was conducted for exploring the steady state transport phenomena of coupled turbulent flow, heat transfer and macroscopic solidification in a continuous stainless steel slab caster. The solidification of molten steel was modeled through the implementation of the popular enthalpy-porosity and/or continuum modeling techniques. A series of simulations was carried out to investigate the effects of …  Lire la suite

This thesis has a three-fold goal: (1) it aims to contribute to studies which analyze the gender dimension in social shaping studies of technology; (2) in its emphasis on the Internet and the new information infrastructure it is a complement to the literature in communication studies on the gendering of communication technologies; and (3) it adds to emergent theories of virtual communities by positing how gendered practices and gender-related activities have influenced the emergence of social policy mores in the evolving information infrastructure. In emphasizing the social factors that shape technological change the thesis departs from dominant approaches towards technology …  Lire la suite

Mouse Ly-6 antigens belong to a family of structurally related GPI-anchored cell surface proteins encoded by tightly-linked, but independently regulated genes on chromosome 15. Functional data so far suggest roles in intercellular communication and trafficking of cells during hematopoiesis and immune responses. High sequence divergence between species has hampered homology cloning of human Ly-6 genes. The major part of this thesis reports the characterization of the first of two human Ly-6 homologues which have been discovered recently. Also reported is work on the generation of recombinant forms of Ly-6 proteins for use in Ly-6 ligand studies and in raising antibodies …  Lire la suite

This dissertation investigates the design of optical receivers and transmitters for VLSI chips. The receivers discussed here run at a moderate speed (100's Mb/s) and they need to be relatively sensitive. However, unlike a traditional fiber communication receiver, a low power and area consumption are very important design considerations. The challenge in designing these receivers comes from satisfying simultaneously all the above requirements. The design of VLSI optical transmitters based on reflection-mode modulators is also discussed. Three optoelectronic technologies, namely FET-SEED, MQW diodes flip-chipped onto CMOS, and epitaxy-on-electronic designs were used to design arrays of transceivers. Current-Mode and buffering techniques …  Lire la suite

Oncogenically transnformed mammalian cells irrespective of their origin synthesize and secrete osteopontin (OPN), a sialic acid rich, adhesive, phosphoglycoprotein, not only in excessive amounts but also in different molecular forms, as compared to their non-transformed counterparts. It has been postulated that OPN has important functional roles in oncogenesis, but its mechanism of action remains obscure. In the present study this question was addressed by using Rat-1 cells transformed by a temperature-sensitive mutant of Rous sarcoma virus (tsB77 cells) which secrete two discrete molecular forms of OPN, a 69-kDa OPN at the non-permissive temperature (41°C and a 62-kDa form at the …  Lire la suite

Although the letter purports to represent fact, it cannot avoid having a partly or potentially fictive status, turning as it does on the complex interplay between the real and the imagined. Consequently, the main critical approach of this paper is to consider the interactions between conflicting modes of expression in eighteenth- and nineteenth-century epistolary fiction. The rhetorical and conceptual contrarieties that I examine are broadly characterized by the contradiction between the implied spontaneity of the familiar letter and the inevitable artifice of its form. Working with familiar letters by four writers between the years 1740 and 1825, I specifically address …  Lire la suite

Nietzsche urges us not to embrace any one perspective of the world, at the same time as he vociferously and repeatedly attacks whole ways of life. These two aspects of Nietzsche's work seem to be in tension with one another--what perspective allows Nietzsche to be so opinionated? Nietzsche insists that all experience is from a perspective and that there is no inherently privileged perspective. This is the "perspectivist" Nietzsche that Derrida focuses on. Yet not only does Nietzsche insist on denigrating the perspective of others, he seems to acknowledge that such attacks are not very worthwhile if they too are …  Lire la suite

Thirty full-scale specimens of five types of connection were constructed and tested under: (a) monotonically increasing shear forces, (b) reversed cyclic shearing forces, (c) reversed cyclic axial forces, and (d) various combination of reversed cyclic shearing and axial forces-all increased gradually in stages until failure using displacement control. These connections were reinforced with anchor bars welded to the steel angle at angles of 45$ sp circ$ and 90$ sp circ$, and/or with 90$ sp circ$ standard hooks at the ends, headed studs welded to a steel plate and some combinations thereof, representing the connections between precast double-tee flanges, or between …  Lire la suite

Interior-point methods have not only shown their efficiency for linear and some nonlinear programming problems, but also for cutting plane methods and large scale optimization. The analytic center cutting plane method uses the analytic center of the current polyhedral approximation of the feasible region to add a new cutting plane. In this thesis, analytic center cutting plane and path-following interior-point methodologies are used to solve the following problems: (1) convex feasibility problems defined by a deep cut separation oracle; (2) convex optimization problems involving a nonlinear objective and a constraint set defined implicitly by a separation oracle; (3) variational inequalities …  Lire la suite

The logic of natural language negation (e.g. no) is prima facie at odds with an exclusively CLASSICAL LOGIC based on SET THEORY. The negation of classical logic obeys the LAW OF NON-CONTRADICTION (according to which an element cannot be both in and not in a set) and the LAW OF EXCLUDED MIDDLE (according to which an element either is or is not in a set). In contrast, natural language negation tolerates APPARENT CONTRADICTIONS (as in, Do you like your supper?---Yes and no) and UNEXCLUDED MIDDLES (as in, Do you love your supper?--- No; Do you hate your supper?---No). These prima …  Lire la suite

Trichloroethylene (TCE) contamination of soil and groundwater is extensive in Canada and the U.S. Under saturated soil conditions, TCE partitions with the organic fraction of soil and under anaerobic conditions is subject to biodegradation to dichloroethylene (DCE) isomers and vinyl chloride (VC). However, biodegradation is slow, and TCE often persists with accumulation of the DCE isomers and VC. The objective of the present study was to determine the effect of soil organic matter (SOM) on the fate of TCE in a saturated soil environment under anaerobic conditions. In natural soil, the presence of inorganic minerals as well as indigenous microorganisms …  Lire la suite

Chronic ligation of one pulmonary artery results in pulmonary vascular remodelling and bronchial angiogenesis, known as postobstructive pulmonary vasculopathy (POPV). In previous studies of POPV, we found that responses of pulmonary arteries to 5-HT and of veins to histamine were markedly increased, but the role of putative factors, such as structure, endothelial modulation and alterations in receptors remains unknown. First, we examined the role of these mechanisms in the differential responses of pulmonary arteries and veins of normal guinea pigs to histamine and 5-HT, using a novel lung explant technique. We found that veins contracted more to both agonists than …  Lire la suite

This Master's thesis examines the status of myth and symbol in postmodern religious discourse, and proposes a new way of understanding representation in religion. The first chapter deals with the sense of symbol as it emerged out of literary and philosophical romanticism, and explores several divergent interpretations of the meaning of the symbol according to modernist and structuralist criticism. The second chapter, after analysing the function of myth and history in religious understanding, connects the romantic symbol to a contemporary hermeneutics based on the aesthetic and epistemological tenets of magic realism. It is my contention in this thesis that magic …  Lire la suite

This thesis deals with the appraisal of the economics of underground conversion in surface limestone mining operations. Software that predicts the time at which an open pit operation should be converted to underground extraction has been developed. The software is based on estimates of capital expenditures required for the underground conversion and for future equipment acquisitions and replacements under both open pit and underground operating alternatives, as well as long-term operating cost estimates for both alternatives. Open pit and underground cost estimates can be entered either directly, or estimated using O'Hara and Suboleski's (1992) cost estimation equations. It is assumed …  Lire la suite

Gap junctions are protein transmembrane channels formed between apposing cells whose primary role is in mediating intercellular communication. This study addressed (1) the role of gap junctions in mammary epithelial cells during the transition from proliferation to quiescence, and (2) the mechanism of gap junction formation between different mammary cell types (heterocellular gap junctions). In the first part, proliferating mammary epithelial cells were induced to enter quiescence by serum deprivation or contact inhibition. Using Western blotting, we observed a dramatic reduction (up to 20-fold) in the expression of the gap junction protein, connexin43 (Cx43), during quiescence. Microinjection of the dye …  Lire la suite

Infrastructure is the foundation and the basic framework which permits cities to function. However, there are significant infrastructure problems in North America. In cities across North America, the infrastructure is deteriorating. The efficiency of a community depends on the condition of its infrastructure. The health and welfare of the residents and the economy of a country requires an efficient and sound infrastructure. North America will not achieve prosperity if it allows its urban infrastructure to decay to the Developing World's levels. Increased new sources of revenue need to be explored by political officials to pay for the cost of upgrading …  Lire la suite