McGill University Thèses et mémoires publiés en 2007

This research project is partnership project involving industrial, university and government collaborators. The overall objective is to develop and enhance tools for use in Resin Transfer Moulding (RTM) design technology in order to re-design existing metallic parts using composite materials. The specific objective of this work is to present preliminary research findings of the development of an optimized design of a leading edge slat (horizontal stabilizer component) from the Bell Model 407 Helicopter. The results presented here focus on the static stress analysis and the structure design aspects. The findings will serve as a basis for future design optimization as …  Lire la suite

To acquire its characteristic structural and functional complexity, the mammalian nervous system must undergo several critical developmental processes. One such process requires factors that regulate the decision of dividing progenitors to leave the cell cycle and activate the neuronal differentiation program. It is shown in this thesis that the murine runt-related gene Runx1 is expressed in proliferating cells on the basal side of the murine olfactory epithelium. Disruption of Runx1 function in vivo does not result in a change in the quantity of progenitors but leads to a decrease in precursor number and an increase in differentiated ORNs. These effects …  Lire la suite

The French government under Philippe Petain, based at Vichy, simultaneously collaborated with the Germans and promoted French patriotism. French artists and designers produced an abundance of posters, paintings, sculptures and other objets d'art, examples of which are included here, to promote the values of the "new order." Although Christian symbols were common, fascist symbols among the mass-produced images support the idea that the Vichy regime was not merely authoritarian, but parafascist. The fine arts were purged of "foreign" influences, yet the German Arno Breker was invited to exhibit his sculptures in Paris. In the spirit of national redressement, traditional French …  Lire la suite

This thesis consider factors impacting the performance of certain overlay networks. We present models and make a number of novel contributions in the form of proposed improvements. Congestion of the underlying network affects any overlay network. Congestion control schemes rely on quick and accurate aggregation of link shadow prices calculated by individual routers. We present a deterministic packet marking algorithm which allows routers to encode these prices in the ECN field of the IP packets traversing the link, and allows the receiver to estimate the total path price. We show, through simulation, that the performance of our algorithm exceeds that …  Lire la suite

Fas Ligand (FasL) binds to the Fas receptor to induce apoptosis or activate other signaling pathways. FasL can also transduce "reverse signals" and thus participate in bidirectional signaling. The FasL intracellular domain contains consensus sequences for phosphorylation and a proline rich protein interaction domain. This latter region of FasL has previously been implicated in FasL reverse signaling and regulation of FasL surface expression. In this report, we sought to identify novel FasL interacting proteins to help understand signaling through and trafficking of this death factor. Using mass spectrometry, we identified sorting nexin 18, adaptin beta, Grb2, PACSIN2 and PACSIN3 as …  Lire la suite

Macrophages are active participants in many important biological processes, including antimicrobial activity, tumour surveillance, apoptotic cell clearance, homeostasis and wound healing. The activity of all cells is under the direct influence of their genetic makeup and macrophages are no exception. Natural resistance-associated macrophage protein 1 (Nramp1, also known as SLC11A1) is a macrophage-restricted gene that confers resistance to intracellular pathogens in mice. Mitogen activated protein kinase activated protein kinase 2 (MAPKAPK-2 or MK2), a substrate of p38 MAPK, is known to influence the activation of macrophages in response to stressors, including the Toll-like receptor (TLR)-4 ligand LPS. Like NRAMP1, MK2 …  Lire la suite

Our objectives were to measure concentrations of glucose, insulin, insulin-like-growth-factor-binding-protein-1 (IGF BP1) and beta-hydroxybutyrate (BOHB) in amniotic fluid (AF), and establish if these concentrations were associated with emergence of maternal gestational diabetes mellitus (GDM). AF samples (n=408) were collected following routine amniocentesis (12-22 weeks gestation). Glucose and insulin concentrations were elevated in our GDM mother-infant pairs, where GDM was associated with a 176g increase in birth weight. Logistic regression showed that AF glucose but not insulin was associated with developing GDM. Non-linear Bayesian probability plots showed that when 2nd trimester glucose was plotted against insulin increases in both were predictive …  Lire la suite

Despite the important benefits of physical activity, many people with autism spectrum disorder (ASD) have difficulty participating long enough to reap the rewards. Poor motor skills, difficulty planning movements, problems functioning in open environments, and low motivation combine to make sustained participation a challenge. This dissertation is a series of three studies designed to develop and assess intervention, based on self-determination theory, which promotes sustained physical activity for adolescents and young adults with ASD functioning at the low end of the spectrum. The studies were carried out at a high school for students with intellectual disabilities over three consecutive years. …  Lire la suite

The "Ecrire le deuil" critique studies how grief takes place in literary works as a fundamental theme, which develops in three different stages: shock and avoidance, disorganization and reinsertion. In the end, the creator's identity is reinforced and transformed by this hardship, which in a way forced him to write. The ten short stories forming the anthology "Le trou dans la vie" deal with all kinds of grief, recent or old, throbbing or diffuse. The characters are all struggling with an absence, and must reconstruct their lives around it. Both subject and driving force of the creative process, loss is …  Lire la suite

The Dystroglycan (DG) complex is a receptor for laminin and is expressed in a variety of tissues. DG functions to maintain cell polarity via interactions with extracellular matrix (ECM) and cytoplasmic proteins. DG is expressed from a single gene encoding a pro-peptide cleaved into two distinct subunits: the ligand-binding alpha-dystroglycan (alpha-DG) and the transmembrane beta-dystroglycan (beta-DG). Both subunits associate non-covalently and form the core of the dystrophin-associated protein complex (DAPC). The DAPC stabilizes membrane proteins and its function is necessary for cell polarity and survival. The DG complex is thought to function as a classical single-pass transmembrane receptor where ligands …  Lire la suite

Treg cells counter-balance autoreactive immune cells in healthy individuals. In the absence of Treg cells, multi-organ immune diseases manifest. Thus, Treg cell defects are suspected to contribute to T1D. Currently, it remains unclear whether Treg cell defects are responsible for the manifestation of T1D. Thus, we hypothesized that Treg cell defects results in T1D. We observed that T reg cells are present in normal frequencies in the thymus and peripheral immune system of diabetes-prone mice. Furthermore, thymic and peripheral T reg cells are operative and mediate regulation by suppressing effector T (Teff) cells in the pancreatic lymph nodes and pancreas. …  Lire la suite

Abstract not available.  Lire la suite

The central theme of this dissertation is the development of a new approach to conceptualize and quantify dependence structures of capture-recapture data for closed populations, with specific emphasis on epidemiological applications. We introduce a measure of source dependence: the Coefficient of Incremental Dependence (CID). Properties of this and the related Coefficient of Source Dependence (CSD) of Vandal, Walker, and Pearson (2005) are presented, in particular their relationships to the conditional independence structures that can be modelled by hierarchical joint log-linear models (HJLLM). From these measures, we develop a new class of marginal log-linear models (MLLM), which we compare and contrast …  Lire la suite

Many concerns have been voiced about the impacts of non-timber forest product harvesting on forest ecosystems, prompting the development of tools for assessing harvest sustainability. The "rapid vulnerability assessment" (RVA) is one method that predicts vulnerability of plants to over-harvesting. However, there is little consensus on how to perform an RVA or interpret the results. The objective of my research is to analyze and refine the RVA method to enhance its utility. I examine factors affecting plant vulnerability used in various versions of the RVA to create a "short list" of important factors. I then use this short list of …  Lire la suite

The purpose of this study was to examine whether focus groups with participation from key stakeholders in the community could identify specific areas that required change in a non-profit community organization. Findings would also provide important feedback for the Board of Directors of a non-profit community organization. Two focus groups were held. One group consisted of nine community stakeholders and in the second focus group six past users of the service participated. Participants gave their comments on program strengths, weaknesses, opportunities and threats in a semi-structured interview using grounded theory in a qualitative format. Program strengths included the community residence …  Lire la suite

The aim of this work was to investigate the role of TGFbeta family members in the induction of cell growth arrest and apoptosis in immune cell types. The TGFbeta superfamily is a large group of evolutionary conserved polypeptide growth factors, involved in different physiological processes. Any deregulation of the different components of the TGFbeta signaling pathway, has been largely implicated in multiple human critical disorders including cancer. Activin, originally isolated from gonadal fluid, and more recently described as an antiproliferative and proapoptotic factor in different cell types has been implicated in different immune functions. In particular, activin and TGFbeta play …  Lire la suite

This thesis is in a manuscript-based format and consists of a collection of papers of which I am first author. Together, these papers form a cohesive report of a single program of research. This thesis comprises the following four manuscripts, which have either been published or accepted for publication, or are currently in preparation for publication: Chapter 1: Valles, H., Kramer, D. L., Hunte, W. (2006) A standard unit for monitoring recruitment of fishes to coral reef rubble. Journal of Experimental Marine Biology and Ecology 336 171-183; Chapter 2: Valles, H., Kramer, D. L., Hunte, W (in press) Temporal and …  Lire la suite

Differentiation is the process of regulated gene expression that gives rise to different phenotypes from a common genotype. Skeletal muscle differentiation, myogenesis, is a good example of this process. Skeletal muscle is susceptible to injury due to direct or indirect causes. If left unrepaired, these injuries may lead to a loss of muscle mass, locomotive deficiency, and even lethality. Thus, understanding the molecular mechanisms behind this process is an important first step in the design of treatment for muscle-related diseases. Once myogenesis is induced, the expression of MRF proteins, such as MyoD and myogenin, is maintained at high levels in …  Lire la suite

We investigate the effect of allowing freedom in the primordial power spectrum of curvature perturbations upon the measurement of other cosmological parameters, in particular the Thomson optical depth due to cosmic reionisation which is present in cosmic microwave background (CMB) observations. We find that the constraint on the optical depth from Wilkinson Microwave Anisotropy Probe (WMAP) data broadens by approximately 10% upon allowing spectral freedom on large scales, and by a slightly larger factor when considering data from future experiments with lower noise in measurements of CMB polarisation. We also present a reconstruction of the primordial power spectrum on the …  Lire la suite

Mustafa, Arif (Internal/Supervisor)  Lire la suite

Objectives. beta-blockers can alter bone turnover and increase bone formation in animals. It is unknown whether beta-blockers have similar bone protective effects in humans. We aimed to estimate the effects of beta-blockers on bone mineral density (BMD) and fractures using data from the Canadian Multicentre Osteoporosis Study, a large prospective cohort study. Methods. All medications, including beta-blockers, taken at baseline and after five years of follow-up were recorded. BMD was measured at baseline. During the five years of follow-up, incident minimal trauma fractures were documented by yearly questionnaires. To compare users of beta-blockers to non-users while controlling for possible confounders, …  Lire la suite

This doctoral dissertation is an experimental ethnographic investigation of the political consciousness and radical modes of livelihoods of marginalized "street" populations in a postconial Latin-American city, and of their connections with the transnational flows of capital, goods, peoples, and symbols of Global Capitalism. Beginning in the streets of Salvador da Bahia in this place I call "Global Brazil", this inquiry presents a focal lens through which to examine how the structural and cultural forces of Late-Capitalism (Jameson, 1994) in a globalized world and the legacy of colonialism play out at the level of local and transnational actors' lived experiences (that …  Lire la suite

This study details the role of genre enhancement and genre upgrading in four parodies by Thomas Morley. These four parodies, first published in Morley's The First Book of Balletts to Five Voices (1595), are based on villanelles from Luca Marenzio's collection I cinque libri di Canzonette, Villanelle et arie alla Napolitana a tre voci (1584-1585). Through the application of specific techniques, Morley transformed Marenzio's villanelles into parodies that, according to Morley's treatise A Plain and Easy Introduction to Practical Music, are higher in the genre hierarchy than their respective models. Comparative analyses will reveal the techniques of genre enhancement and …  Lire la suite

Jones, Peter J. H. (Internal/Supervisor)  Lire la suite

Cerebral Cavernous Malformations (CCM) and Intracranial Aneurysms (IA) are cerebrovascular disorders that can lead to a hemorrhagic stroke and other neurological problems. CCMs are characterized by abnormally enlarged capillary cavities while IAs are saccular outpouchings of intracranial arteries. CCM is found in approximately 0.4% to 0.9% of the population, while IA is more common (3-6%). This dissertation aimed to add to the body of research for CCM and IA and was divided into two parts. Initial work focused on the characterization and identification of the genes involved in CCM; the second phase focused on the identification of a susceptibility gene …  Lire la suite

This dissertation examines five figures associated with magic in contemporary literature: voodoo ghosts, magicians, automata, fortune tellers, and freaks. While glancing at a number of novels, this study chiefly examines five books published between 1972 and 2001: Ishmael Reed's Mumbo Jumbo, Allen Kurzweil's A Case of Curiosities, Michael Chabon's The Amazing Adventures of Kavalier & Clay, Susan Sontag's The Volcano Lover, and Thomas Wharton's Salamander. In these novels, figures of magic display different aspects of the work of representation, coded as magic, as well as the effect of magic on representation. In fiction, magic localizes enchantment as an inherent product …  Lire la suite

Considerable research has been performed on persistent-anomaly structures for the Northern Hemisphere winter. However, atmospheric blocking structures during the warm season also have a considerable impact on weather and climate, as manifested through heat waves, floods, and droughts. In particular, atmospheric blocked flow has a profound impact on anomalously-dry regimes over the central North American continent. In order to provide a better understanding of the life cycle of the atmospheric blocking events and their relation to fast-climate phenomena, we analyse persistent height-anomaly structures derived from the National Centers for Environmental Prediction (NCEP) global reanalyses. We devise an objective criterion for …  Lire la suite

Introduction. Numerous studies have suggested that maternal care can influence the development and expansion of an individual's self-esteem. Yet the neural mechanisms of this relationship remain unexplored. Incidentally, it has already been demonstrated that a brain region, namely the Hippocampus (HC) is associated with both self-esteem and maternal care. Thus suggesting that there may be a three-way relationship. This also provided the impetus to speculate that a similar interaction could be observed in other brain regions like for example, the Dorsolateral Prefrontal cortex (DLPFC) and the Medial Prefrontal Cortex (MPFC). Therefore, the aim of this study is to scrutinize the …  Lire la suite

Dhahran, Saudi Arabia is home to the largest transnational oil corporation and gated suburban residential compound in the world. In exploring Saudi ARAMCO, I will undoubtedly be opening to the centerfold of all socio-cultural, religious, political, economic and pedagogical forces affecting today's geo-political affairs. The theoretical focus of my thesis comes from both a global and critical pedagogy framework that investigates the nature of asymmetrical power relations on micro, meso and macro levels. Additionally, the multiple perspectives I have gained while living in Dhahran and mediating between identities including girl, woman, South-Asian, Canadian, expatriate, student and artist have provided me …  Lire la suite

Dans cette thèse, nous présentons les détails mathématiques et d'implémentation d'une méthode \emph{ab initio} pour le calcul des propriétés de transport quantique polarisé en spin de dispositifs spintroniques de taille atomique sous un différence de potentiel appliquée. La méthode est basée sur la théorie des fonctionnelles de la densité (DFT) dans le cadre du formalisme des fonctions de Green hors équilibre (NEGF) de Keldysh pour calculer les densités de spin auto-consistantes. Cette technique de pointe étend les travaux précédents: i) en reformulant la théorie dans l'espace de spins de telle manière que la densité de charge hors équilibre peut être …  Lire la suite

The following study is an attempt to ascertain the most adequate way to understand the relationship in modernity between religion and technology. This relationship is first analyzed by looking at a common way in which technology has been categorized and discussed as representing the religion of modernity. The first chapter critically evaluates several popular and scholarly works which contain arguments for understanding that the modern world participates in some kind of 'religion of technology.' The inadequacies of these arguments are shown to arise from the problematic ways in which they invoke the meanings of both religion and technology. The suggestive …  Lire la suite

The literature review indicates that studies on the structures and properties of perovskites materials have shown attractive applications in the fields of energy, catalysts and sensing materials for fuel cell and sensing industries. Kinetic phenomena in thin film systems, such as solid state amorphization and interface reactions due to diffusion during thin film deposition, are introduced indicating that thermal stability is a concern in thin film sensor device application. The principle of traditional methods of materials characterization is briefly discussed. Emphasis is placed on the functions of analytical transmission electron microscopy. The SrFeO3/SiO2/Si and SrFeO3/Al 2O3 thin film systems have …  Lire la suite

This dissertation comprises three essays. In the first essay, I develop a contingent-claims model to investigate the impact of managerial entrenchment on corporate policies and security valuation. The model emphasizes the role that managerial agency issues play in determining both a firm's dividend payout and capital structure. I show quantitatively that self-interested managers' leverage choices deviate from those ex ante maximize firm values. The results suggest that dividend yields are negatively affected by both leverage ratios and managerial entrenchment. They provide implications for empirical research attempting to relate dividend policy to capital structure. In addition, the model offers a new …  Lire la suite

The magnetic properties, crystal and magnetic structures of Nd5 SixGe4-x were investigated by ac susceptibility and high resolution neutron powder diffraction. The magnetic and crystalline phase diagrams were derived. Four distinct structures exist in the Nd 5SixGe4-x system: Gd5Ge 4-type [O(II)], Gd5Si2Ge2-type (M), Gd5Si4-type [O(I)], and Zr5Si4-type (T). The refinements of the neutron powder diffraction patterns revealed that the Nd5SixGe4-x compounds exhibit mixed ferro-antiferromagnetic structures. The ac susceptibility measurements showed that the magnetic ordering temperature of Nd5SixGe 4-x increases slightly with increasing silicon content, except that it increases by a factor of 2 in the orthorhombic Gd5Si 4-type [O(I)] phase …  Lire la suite

Il n'y a aucune solution de exacte pour beaucoup de modèles non-linéaires à effets mixtes (NLME) exprimés comme un ensemble d'équations ordinaires (ODE) en modèles de compartiment. Cette thèse passe en revue plusieurs méthodes et outils courants de logiciel pour NLME, et explore une nouvelle manière d'estimer des effets mixtes non-linéaires en modèles de compartiment basée sur le cadre de la méthode de profilage généralisée proposée par Ramsay, Hooker, Campbell, et Cao (2007). Quatre types de paramètres sont identifiés et estimés d'en cascade par une optimisation de multiple-niveau: le paramètre regularisateur est choisi par le critère de la contre-vérification généralisée …  Lire la suite

This thesis falls into the field of tactile displays that are meant to produce realistic tactile sensations, which replicate tactile sensations arising naturally when humans interact with the real world. To begin with we need to know the biomechanics of the glabrous skin in human subjects. To this end, small patches of fingerpad skin are tested in vivo for their biomechanical properties under tangential loading. The skin is quasi-statically stretched and sheared to obtain its effective Young's modulus. Moreover, isotonic and isometric testing conditions are implemented to identify the viscoelasticity model of the skin. The results show a great deal …  Lire la suite

CO2 absorption behaviour of four commonly used cement based building products: cement paste, concrete block, expanded polystyrene bead (EPB) and cement-bonded cellulose fiberboard are studied. Cement products are manufactured following industry formulation and process, and carbonation curing takes place in a chamber under a pressure of 0.5 MPa, at ambient temperature, for durations of mostly 2 to 8 hours with both pure carbon dioxide gas and flue gas. The flue gas of 13.8% CO2 content is collected from a typical cement kiln without separation. Influencing factors on carbon uptake, long-term strength as well as microstructure development are studied. It is …  Lire la suite

Self-heating of sulphide minerals has a potential for serious impact on environment and safety in mining of ores, and storage and transport of concentrates. A research program, focused on the investigation of the conditions under which the H2S is produced from pyrrhotite-rich materials, has been initiated using the self-heating facility and technology developed at the Noranda Technology Centre. It is hypothesized that H 2S production could be important in self-heating as the exothermic heat of oxidation of H2S to SO2 is greater than that for oxidation of S to SO2. The hypothesis of liberation of H2S was tested using copper …  Lire la suite

Membrane rafts are small plasma membrane domains that contain high levels of cholesterol and sphingolipids. They have been implicated in processes as diverse as signal transduction, endocytosis and cholesterol trafficking. Traditional methods for the biochemical preparation of lipid rafts involve the extraction of membranes with nonionic detergents followed by the separation of a low-density, detergent-resistant membrane fraction on density gradients. Because of concerns regarding the possible introduction of artifacts through the use of detergents, several methods were developed for the isolation of lipid rafts that do not involve detergent extraction. In this study, we compared three different biochemical methodologies of …  Lire la suite

This dissertation is in the form of three essays on the topic of component and long memory GARCH models. The unifying feature of the thesis is the focus on investigating European index option evaluation using these models. The first essay presents a new model for the valuation of European options. In this model, the volatility of returns consists of two components. One of these components is a long-run component that can be modeled as fully persistent. The other component is short-run and has zero mean. The model can be viewed as an affine version of Engle and Lee (1999), allowing …  Lire la suite

Acquisition of full developmental competence of oocytes not only occurs during growth stage, and the final preparation during oocyte maturation is also critical. Previous studies have shown that nuclear maturation can occur spontaneously following culture in vitro; however, there may be some insufficiency in cytoplasmic maturation of the in vitro matured oocytes. But till now, the differences of the events of cytoplasmic maturation between in vitro and in vivo matured oocytes are still not clear. Ovarian stimulation by gonadotrophins is used to permits the growth and development of follicles, to time the initiation of pre-ovulatory oocyte maturation, and to increase …  Lire la suite

The development of numerical skills in children with Down syndrome is an area of research that has been neglected in the literature despite overwhelming evidence of its importance, both pedagogically, and for everyday functioning. The present study examines two important sub-skills of numeracy. Twelve boys with Down syndrome were compared to 24 typically developing boys (matched on verbal mental age and on chronological age) on two novel, computerized tasks designed to measure sequential processing and counting. Boys with Down syndrome performed comparably to both groups of typically matched controls on the sequential task. However, differences emerged when boys with Down …  Lire la suite

Induction programs have become increasingly popular and necessary as school districts attempt to meet the needs of the millions of beginning teachers they must hire. Though originally designed to curb the attrition of novices, attention is now focusing on how these programs may affect student achievement and teacher development. While the components of such programs vary, one constant is the provision of an experienced colleague as a mentor. University professors, though involved in beginning teacher preparation, are rarely included in their ongoing support once they leave the institution. The present study attempts to discover a theoretical rationale for the involvement …  Lire la suite

The present study aims to examine the modern Chinese Pure Land thought and movements, which are part of the general context of reforms that involved the whole Chinese Buddhist community starting from the beginning of the 20th century. In this study, I examine (1) the socio-political context of modern China when Chinese Buddhist communities began to re-think their traditions and reform monastic education, under the influence of socio-political chaos and Western culture; (2) Ven. Yinguang's (1861--1940) syncretism of Pure Land thought with Confucian ethical teachings, which promoted a more secular and lay movement in response to Western influence; (3) Ven. …  Lire la suite

During the past decade, self-assessment has become a major research area; however, contradictory findings have been reported. This study investigated the effectiveness of self-assessment and examined some possible factors that might influence the accuracy of self-assessment. Participants were 32 English as a second language (ESL) graduate students and an experienced ESL teacher at McGill University. The student participants were divided into a control group and an experimental group while the researcher and the ESL teacher served as raters. Both quantitative and qualitative data were generated. The results indicated that the experimental group outperformed the control group. Some possible causes of …  Lire la suite

Human growth hormone (hGH) is a key regulator of postnatal growth and metabolism, exerting its effects through a specific cell-surface receptor, hGHR. Eight hGHR mRNAs are produced by the hGHR gene due to transcribing from different 5' non-coding exons. Four (V2,V3,V5,V9) are ubiquitously expressed, whereas the others (V1,V4,V7,V8) are present only in normal postnatal liver, suggesting that different promoter usage is a mechanism for developmental and tissue-specific regulation of the hGHR gene. hGH influences adipose tissue development and function. By 5'RACE screening of a human adipocyte cDNA library, I determined that the V2 transcript is the predominant (~90%) hGHR mRNA …  Lire la suite

Airborne particulate matter has a negative effect on respiratory health in both children and adults, and the ultrafine fraction of particulate air pollution is of particular interest owing to its increased ability to cause oxidative stress and inflammation in the lungs. In this investigation, our objective was to characterize ultrafine particle (UFP) counts in homes, schools, and transportation environments and to develop models to predict such exposures. A number of important determinants of UFP exposures were identified including ambient temperature and wind speed for transportation environments, outdoor UFPs for classrooms, and electric oven use, cigarette smoking, indoor relative humidity, and …  Lire la suite

L'ironie abonde dans les conversations mais la façon dont elle est procédée est encore énigmatique. Deux expériences ont été menées pour comparer l'ironie au langage littérale, pour étudier les différences entre des situations positives et négatives, et pour voir si des caractéristiques individuelles sont liées à un traitement accéléré de l'ironie. Les résultats ont montrés que l'ironie est traitée plus lentement que la langage littérale (p < .05). L'ironie est perçue comme étant plus vraisemblable dans des situations négatives que positives (p < .05). Les déclarations anormales sont moins longues à rejeter que celles ironiques. L'utilisation du sarcasme et la …  Lire la suite

In this paper, the evocative nature of patina on stringed instruments is linked to the four agents of transformation that create it. These correspond to four nostalgic values: nostalgic reflection on the passage of time; nostalgia inspired by use; nostalgia for craftsmanship and pastoral nostalgia. Actors in the subfield of restricted cultural production of stringed instruments invoke one or more of these nostalgic values explicitly as a means to rationalize their actions to competing actors and to the broader public in their battle for status. Patina offers visible proof of their claims. Actors in the subfield of large-scale cultural production …  Lire la suite

Aquatic plants play an important role in the survival and proliferation of invertebrates in freshwater ecosystems. Exotic plants are now common in North American lakes and rivers, where they may displace native plants, thereby potentially altering epiphytic invertebrate communities. Differences in aquatic invertebrate communities on native and exotic plants are examined here through (1) a meta-analysis of published data, and (2) two field surveys in northeastern North America that compared invertebrates on the exotic Myriophyllum spicatum and Potamogeton crispus to those on their native congeners. The meta-analysis revealed that exotic plants generally support lower invertebrate abundance than do natives, while …  Lire la suite