McGill University Thèses et mémoires publiés en 2005

It is generally accepted that global levels of CO2 will roughly double over the next century. Because of their large population sizes and fast generation times, microalgae may adapt to global change through novel mutations fixed by natural selection, such that future populations may be genetically different from contemporary ones. The prediction that microalgae may respond evolutionarily to rising CO2 was tested using populations of Chlamydomonas reinhardtii grown for 1000 generations at increasing CO2. Laboratory populations grown at high CO2 did not show a direct response to selection at elevated CO2, instead evolving a range of non-adaptive syndromes. In addition, …  Read more

This thesis sets out to test the Full Transfer Full Access hypothesis (FTFA), which claims (i) that second language (L2) learners start out with the parameter settings instantiated in their first language (L1) grammars ('full transfer') and (ii) that they can subsequently reset parameters to the target L2 settings where these differ from the L1 settings, provided the required (triggering) positive evidence is available in the L2 input ('full access'). Three studies on the L2 acquisition of two verb movement parameters, the V2 parameter and the Split-IP parameter (SIP), are reported. The first study investigates 'full access', testing whether English-speaking …  Read more

Sweet corn is classified among highly perishable horticultural commodities. Thus, it can be deteriorated rapidly after harvest resulting in high loss and poorer produce quality. Sweet corn's sugar loss is about four times higher at 10°C compared to 0°C. Precooling, immediately after harvest, has shown to be an effective method to maintain the quality for a wide range of fresh fruits and vegetables during storage. Further, this method leads to reduction in metabolism and respiration rate of the produce, retardation of its senescence, and inhibition of growth of pathogens. In addition to diminishing postharvest losses of the produce, efficient precooling …  Read more

Markov Chain Monte Carlo (MCMC) methods are employed to sample from a given distribution of interest, pi, where either pi does not exist in closed form, or, if it does, there exist no efficient methods to simulate an independent sample from it. MCMC methods create an ergodic Markov chain {Xn, n = 1, 2...} with stationary distribution pi such that as n tends to infinity, the distribution of Xn approaches pi. A wealth of diagnostic tools for convergence assessment of MCMC methods have been proposed, yet none has proved to be completely dependable and easy to implement. This thesis will …  Read more

The interaction of two scalars (both temperature) emitted from concentrated line sources is studied in fully-developed, high-aspect-ratio, turbulent channel flow. The thermal fields are measured using cold-wire thermometry in a flow with a Reynolds number (Uh/nu) of 10200. The transverse, total RMS temperature profiles are a function of the separation distance between the line sources (d/h), their average wall-normal position (ys_av/h), and the downstream location (x/h) (relative to the line sources). The non-dimensional form of the scalar covariance, the correlation coefficient (rho), is a function of the same parameters and quantifies the mixing of the two scalars. In all cases, …  Read more

This dissertation explores the legal issues raised by the participation of private persons in the settlement of international economic disputes, using the potential enlargement of legal standing in the World Trade Organisation (WTO) as a case study. In the first part, a typology of the special regime of responsibility of WTO Members is drawn, to serve as a "normative bridge" between the twin phenomenon of legalisation of international trade relations and judicialisation of international trade dispute settlement. In the second part, a comparative study of the participation of private persons in the settlement of international economic disputes is conducted, using …  Read more

This thesis is about the possibility of addressing power disparities in divorce mediation in order to maximize the benefits that this alternative practice offers. It describes the development of Alternative Dispute Resolution (ADR) in general and of divorce mediation in particular, primarily through a feminist lens. In doing so it discusses the promise that feminist proponents saw in mediation initially, and then proceeds to describe the breaking of the promise that developed into some of the harshest critique of this process. The thesis explores a critical element of this critique, namely the problematic nature of utilizing mediation in the face …  Read more

Neurons found in the superficial dorsal horn (SDH), particularly in the first lamina, are critical for mediating transmission of pain-related information to the brain, and thus influence pain perception. Excitability control of these neurons derives largely from a network of inhibitory interneurons that render dynamic inhibition via the GABA (gamma-aminobutyric acid) and glycine neurotransmitter systems. However, the processes that contribute to the regulation of these systems under normal and pathophysiological conditions have not been well elucidated. To shed light on these issues, our studies employed a variety of techniques to examine mechanisms of plasticity of intrinsic inhibition in the SDH. …  Read more

Tethered helium balloons are known to be useful in applications where a payload must be deployed at altitude for a long duration. Perhaps the simplest such system is a helium-filled sphere tethered to the ground by a single cable. Despite its relative simplicity, there exists little data about light tethered spheres in a fluid stream. The current work focuses on an investigation of the dynamic characteristics of a spherical aerostat on single tether. A test facility was constructed to gather the experimental data required for a characterization of the system. The balloon's drag coefficient is extracted from the position measurements. …  Read more

In this thesis, we present many facts pertaining to the Poincare sphere, also called the Bloch sphere. We demonstrate how to compute the R3 rotation matrix that corresponds to a given unitary matrix and, inversely, the unitary matrix corresponding to each rotation matrix. We show that any set of quantum states that is contained in a plane through the Bloch sphere can be encrypted perfectly using only one bit of key, while two bits are required to encrypt any other set. We also try to find equivalent statements for spaces of dimension higher than two. Last, we study the generality …  Read more

Despite the ubiquity of transposons in eukaryotic genomes, their evolutionary role remains controversial. The discovery of several domesticated genes has suggested that transposons can gain host functions, and thus contribute to the evolution of their host. Here, I present the results of a genome-wide screen for transposon-derived host genes, which was based on the idea that, once domesticated, the open reading frame of such elements would be maintained, while terminal structures necessary for transposition would be lost. Eight-hundred-and-sixty-three such transposon-dissociated elements were mined from the genome of Arabidopsis thaliana var. Columbia-0, of which less than 10% are associated with expression …  Read more

The current practice of snowfall forecasting in Canada is to determine the snow water equivalent (SWE) expected to precipitate using a numerical weather predication model and then multiplying this amount by a snow/SWE ratio to determine the forecast snow depth. The 10:1 "rule of thumb" is still widely used operationally as this ratio, even though it is well-known to introduce error in the forecasts because the density of snow is highly variable. In 2003 Ivan DubE developed a decision tree type algorithm to find the snow/SWE ratio which has subsequently been automated in 2004 by the Meteorological Service of Canada …  Read more

The last decade has seen an increase in empirical research pertaining to coaching science and education. A great deal of research has focused on coaches of elite able-bodied athletes, while coaches of athletes with a disability have generally been overlooked. In a recent analysis of disability sport, only 5% of empirical publications pertained to coaching. Thus, the current study addressed the gap in the literature by examining the knowledge of disability sport coaches. Six elite level Canadian coaches of swimmers with a physical disability were interviewed using an unstructured, open-ended interview format. Four categories emerged from the analysis: coach background …  Read more

This study proposes to analyze the phenomenon of tax treaty abuse and the use of tax treaties as tools to avoid or minimize the taxation by residents doing business in a foreign jurisdiction. This study analyses a particular strategy using tax treaties known as "treaty shopping." This paper will argue that treaty shopping constitutes an abuse of the tax treaty regime. However, this study rejects the traditional arguments against treaty shopping and proposes a different basis to challenge the legitimacy of this practice and to explain why this strategy constitutes an improper use of tax treaties.  Read more

This dissertation clarifies ethnoarchaeology's role in post-positivist epistemology through both a critical re-examination of ethnoarchaeology's position within archaeology and a study of household vessel exchange and consumption in the Inland Niger Delta of Mali. I argue that ethnoarchaeology meets its epistemic raison d'etre by achieving theoretical independence from archaeology's general theories. Independence is "built-in" to ethnoarchaeological study by focusing explicitly on the way material culture is used in daily practice; in particular, by re-embedding material culture in the "modern" contexts where it is used. Ceramic exchange in the Inland Niger Delta can not be understood apart from either the exchange …  Read more

Merger review has gained in importance in both Canada and the European Union since the enactment of the Competition Act in 1986 and the Merger Regulation in 1989 respectively. The increase in international trade and the globalization of the world economy have forced both jurisdictions to reform the relevant provisions of their Competition law as concerns mergers in order to keep pace with these rapid changes. The thesis offers a thorough description of the current merger review laws in both systems, and the proposed amendments under consideration in Canada and the EU. In the last chapter, the author compares both …  Read more

The term nowcast is used to emphasize that a forecast is being produced for very short lead times, typically 0 to 6 h. Most nowcasting systems use weather radar as the primary tool for forecasting. Modern techniques use computer algorithms to compute these short-term forecasts, and have been shown to have more skill than human forecasters or numerical models alone. Applications of nowcasting span across many industries, with aviation being of particular importance. The essence of nowcasting can be summarized in two steps: (1) obtain a motion estimate for an existing storm, and (2) advect the current storm using the …  Read more

Introduction. Endoscopic placement of stents is the preferred treatment for palliation of obstructive symptoms in non-operative candidates but significant differences in procedure and stent-related costs, patency of stents survival of patients exist. Aim. To determine the cost-effectiveness of two strategies using Polyethylene (PE) stents (PE with replacement on demand; PE with routine exchange every 3 months), as well as uncovered (U-SEMS) and covered self-expandable metal stent (C-SEMS) in the management of distal malignant biliary obstruction. Methods. A Markov model comparing four different initial approaches was designed: (1) PE stent with replacement on demand (PE-D); (2) PE stent changed every 3 …  Read more

Using Monte Carlo techniques, the 18 MV accelerators CL2300 and CL21EX, 8 physical wedges and the enhanced dynamic wedge have been modeled and validated. The simulated PDDs, profiles, output factors and wedge factors are in good agreement with measured values. These models have been applied in the dose calculation of lung cancer patients to investigate the effect of tissue heterogeneity by comparing with the CADplan treatment planning system with and without heterogeneity correction. Plan I and plan II for 8 patients have been re-calculated with the Monte Carlo method. On average, the mean PTV dose calculated with the Monte Carlo …  Read more

This study was undertaken to characterize the nod and sdh operons of Bradyrhizobium japonicum and Sinorhizobium meliloti. Ten putative B. japonicum mutants with altered nod gene induction characteristics were isolated by screening mutants for genistein-independent nod gene expression. The mutants were found to have higher nodY expression than the wild-type in the presence of genistein. The increased sensitivity of all mutants to genistein was more apparent under suboptimal inducer concentration (0.1muM) and/or temperature (15°C). The expression of nodY gene induction was determined for five strains (Bj30050, 53, 56, 57, 58) under different temperature and inducer conditions. These five strains were …  Read more

During 30 years of worldwide use, measles virus (MV) vaccination has brought about a dramatic reduction in the morbidity and mortality due to measles infection. In spite of extensive evidence confirming the safety of the vaccine, concerns have recently been raised about possible links with inflammatory bowel disease (IBD) and autism spectrum disorder (ASD). The publication of this work, which arose principally from a research group in the United Kingdom, has caused a drop in vaccination uptake and subsequently resulted in re-establishment of endemic measles in various parts of Europe. In this thesis, we sought to replicate the real-time reverse …  Read more

Glass Fibre Reinforced Plastic (GFRP) composite structures are increasingly used in waterfront and marine environments due to their corrosion resistance. While the GFRP materials have demonstrated excellent tensile capacities, they also present quite low elastic moduli compared to steel. Consequently, local buckling and excessive deflection are always performance-limiting factors in design of thin-walled composite structures that use low-tech FRP. The research reported herein is focused on the buckling and deformation analysis of a pultruded sheet pile wall subjected to uniformly distributed load and harsh environmental exposures. Prior to structural analysis, material properties of the composite sheet pile were determined by …  Read more

This thesis consists of three essays in monetary economics and international macroeconomics. Chapter one uses Canadian data to evaluate the performance of money growth targeting and inflation targeting policy rules, especially when they react to asset price changes. There are three important findings. First, estimates of the policy rules consistent with both regimes provide evidence that the Bank of Canada has systematically reacted to stock price bubbles and exchange rate changes. Second, a counterfactual experiment reveals that, the high inflation of the 1970s and early 1980s could have been avoided if the Bank of Canada had responded more strongly to …  Read more

The development of new methods of generating alpha-amino acid derivatives via multi-component reactions remains an important challenge. The primary goal of this study is to develop new transition metal-mediated routes to synthesize these alpha-amino acid derivatives using combinations of simple reagents, such as imines, carbon monoxide, acid chlorides and organotin reagents. The proposed approach requires the sequential insertion of imine and carbon monoxide into late transition-metal sigma-bonds, as well as the further reactivity of the products. In chapter 2, the ability of the nickel complex L2Ni(CH 3)N(R)=C(H)R'+X- (L2 = chelating nitrogen ligands, X- = non-coordinating counteranion) to mediate the insertion …  Read more

This thesis reviews the legal, political and technical aspects of aeronautical information, with a particular focus on the situation of aeronautical information in Europe. It portrays the evolution of aeronautical information and its current nature. It looks at the responsibility for the publication of aeronautical information and the evolution of that notion due to recent trends towards corporatisation to the detriment of full State ownership. It also examines the question of liability for the publication of aeronautical information, including the various legal regimes under which victims of defective aeronautical information can claim compensation, as well as the legal mechanisms underlying …  Read more

Prolactinomas account for 40% of all tumors in the pituitary, an important gland of the endocrine system, and secrete excess amount of prolactin hormone. We recently identified a member of the TGF-beta superfamily of growth factors, activin, as an important regulator of prolactin expression and cell growth. Activin inhibits prolactin expression through inhibition of expression of a pituitary-specific transcription factor, named Pit-1. Pit-1 plays major roles in the development and maintenance of the anterior pituitary gland integrity. In this study, I investigated the intracellular signaling pathways and transcriptional mechanisms by which activin controls Pit-1 activity. I demonstrate that in addition …  Read more

Ground Ambient Noise (GAN) readings were recorded across the island of Montreal and the recordings were processed using the horizontal-to-vertical spectral ratio technique. One-dimensional non-linear soil dynamic analyses were performed over a large database of boreholes in Montreal using the computer program SHAKE. The resulting predominant frequencies of vibration were used as the main parameter to define the seismic microzonation of the island of Montreal. The frequencies are mapped and used to identify twelve zones with potential seismic amplification problems. The largest ratio was obtained in the zone located at the eastern tip of the island of Montreal where long-period …  Read more

Over time, the Italian community has become an integral part of Canada's ethnic mosaic. However, to what 'ethnic' cost has this integration occurred? This thesis looks at issues of ethnic retention among successive generations of Italian families living in Montreal. Focus is placed on three fundamental questions: (a) How did the Italian community change through generations? (b) Are the young generations displaying signs of symbolic ethnicity? and (c) How can the ethnic identity of Italians in Montreal be defined in 2005? Drawing on Herbert Gans' symbolic ethnicity approach, the initial hypothesis suggests that socio-economic upgrade spurs an ethnic consciousness founded …  Read more

Destruction of ecosystems and infrastructure can be caused by melting of massive ice within permafrost. To predict potential melting caused by natural and human disturbance, we need to know the nature and origin of massive ice deposits. The purpose of this research was to evaluate the nature of massive ice in coarse-grained sediments that accepted theories suggest should not occur. Degradation of ice-rich granular resources is expensive and difficult to rehabilitate and can cause developmental thermokarst, overestimation of granular resources, disturbance of wildlife habitat and create conflicts with traditional land uses. To locate massive ice we used a resistivity geophysical …  Read more

Chronic obstructive pulmonary disease (COPD) is characterized by an expiratory flow limitation, as well as an evident reduced exercise capacity compared to that of healthy age-matched individuals. Clearly, the expiratory flow limitation plays a significant role in this exercise intolerance; however, the extent of the contributions of other systemic factors remains unclear. More specifically, there is little data thus far on the role of blood flow delivery as a possible exercise limitation in COPD, especially in light of the potential interactions between cardiac output (Qc) and pulmonary hyperinflation. Thus, the purpose of this study was to compare the slope of …  Read more

Groups where the discrete logarithm problem (DLP) is believed to be intractable have proved to be inestimable building blocks for cryptographic applications. They are at the heart of numerous protocols such as key agreements, public-key cryptosystems, digital signatures, identification schemes, publicly verifiable secret sharings, hash functions and bit commitments. The search for new groups with intractable DLP is therefore of great importance. The study of such a candidate, the so-called generalized Jacobians, is the object of this dissertation. The motivation for this work came from the observation that several practical discrete logarithm-based cryptosystems, such as ElGamal, the Elliptic and Hyperelliptic …  Read more

The practice of international trade is specific and evolves rapidly in accordance with its needs. Today arbitration constitutes the usual way to settle disputes of international commerce. However, certain rules of arbitration do not seem to be adapted with this practice. The written form of the arbitration agreement as required by, inter alia, the New York Convention and the UNCITRAL Model Law on International Commercial Arbitration is one of them. First this thesis presents the rules of these two instruments. Then international trade's practice is examined, and especially the incorporation of arbitration clauses by reference and the use of electronic …  Read more

The epitaxial growth of ultrathin films of NaCl was achieved on a Cu(100) substrate at room temperature. The growth mode was observed to be of the Stranski-Krastanov type using non-contact AFM, with well-oriented square islands growing on top of the first monolayer of NaCl. The frictional properties of different monolayers were measured using contact mode AFM. The friction contrast between the different monolayers of NaCl was found to be too small to be measured within the noise. Atomic stick-slip measurements were performed on a NaCl island. The results are discussed in comparison with relevent literature on thin films of alkali …  Read more

Tax competition between tax sovereignties is a fact. We focus here on the international tax competition. Taxation is one of the tools of governance that States use to direct their policies. Tax authorities try to diminish the burden of their taxpayers to improve the national economic and social welfare. To aim this objective, Governments intensify the competitiveness of the domestic trade and/or attract foreign investments. Because every States share the same goal, Governments compete with each other on the tax field. This tax competition is qualified as beneficial on the one hand, and one the other hand---ever more often---the adjective …  Read more

1826 is the date attributed to the very first known photograph, Nicephore Niepce's "View from the Window at Gras." For traditional historians of photography this date marks the moment when the genius of man was finally able to merge the knowledge of chemistry with that of optics to create the most amazing technology of visual representation. However, those same historians recognize that the two essential components of photography---the camera and the properties of silver halides---had been known for centuries before the first photograph was ever taken. This thesis explores two fundamental questions: Why wasn't photography invented soon after its major …  Read more

This study examines why excellent working class rural female teachers remain in teaching. Although the teachers of this study admit to having experienced disillusionment during their teaching careers, they have remained passionate and enthusiastic educators, and are the teachers most often cited when colleagues, students and parents are discussing "good" teachers. Thus, this study seeks to determine the factors that influence these women educators to remain in education and to remain passionate about education. The original supposition that an administrator was a determinative variable in influencing the rural female educators proved to be erroneous. For the women of this study, …  Read more

In the last decade, the video game industry has shown unparalleled growth, both in revenue and in development complexity. Modern video games are built using powerful game development tools. However, given their complexity and scope, these tools are ill-suited for the undergraduate academic environment. Minueto is a platform independent game development framework specifically designed for undergraduate students. Originally developed to help students of the course COMP-361 for their game programming project, Minueto offers a simple object-oriented API that is ideal for any 2D game development. Minueto's simple design allows students to quickly learn the framework and avoid the overhead typically …  Read more

A new distortion measure for audio coding is proposed, posed as a distance measure on the space of excitation patterns. We investigate the psychoacoustic properties of the measure, as well as the implementation issues that arise under a constrained-distortion coding structure. Experimental results show that the excitation distortion metric produces higher-quality coded files than the usual Noise-to-Mask ratio measure, at the same rate.  Read more

The Large Adaptive Reflector is a Canadian design for a new radio telescope. The receiver is held at the focus of the reflector by an aerostat tethered to the ground by multiple tethers. One of the main goals in the design of this system is the minimization of the motion of the receiver. Most perturbations are produced by the action of the wind on the aerostat and transmitted to the confluence point via the leash that connects the aerostat to the receiver. For that reason, this work focused on leash-related stabilization techniques. Computer simulations were used to evaluate the benefits …  Read more

In this thesis, we wish to observe French Canadian literary criticism in 1950, during what is referred to as a "dark age" of the intellectual and artistic history. Hence, we decided to analyze three newspapers literary pages, La Presse, Le Quartier latin and Le Devoir, and a specialized journal, Lectures, published in Montreal. Nowadays, this literary criticism is looked upon as paradoxical and outdated because its aesthetics concerns are bent by morals. Thus, we tried to enlighten its axiological criteria, supported by liberal or catholic ideologies, already enabling very modern aesthetics comments, and by doing so, bring into favor a …  Read more

The deregulation movement affecting the industrialized countries forced the governments to refocus their prescribed standards. In some jurisdictions, the difficulty raised by this practice resulted in the establishment, with the industry, of a negotiation plan for environmental agreements. In this document, we will explore the problematic of the characterization in law of environmental agreements reached by the administration and the industry. Furthermore, we will evaluate the pros and cons of using this system in the public administration. The subject of this research is mainly based on the depollution attestation adopted in 1988 by the Assemblee Nationale du Quebec to oversee …  Read more

The present work aims to assess the ductile behaviour of porous Inconel 625 nickel-based superalloys, produced by Metal Injection Moulding (MIM). A qualitative study of the local behaviour was conducted through a series of simple finite element models. Obtained results have been analyzed and compared to more common materials. The following study focuses on the strain localization phenomenon leading to ligament failure between 2 pores relative to their dimensions, their orientation, the distance separating them and the triaxiality ratio. Obtained results demonstrated that the dimensions of the plastic zone in the neighbourhood of pores proportionally increase with pore diameter. Hence, …  Read more

Rehabilitation Centres receive both children in need of protection and youths who have committed a criminal offence. In all cases, the Centre's mandate is to help them readjust to society. In pursuing this mandate, educators resort to measures of seclusion, time-out or withdrawal, whether for therapeutic or disciplinary reasons. All of these measures, however one wishes to call them, may be effected through confinement. The children are thus liable to be locked into their own room, into a specially designed time-out room or into a seclusion room, the time of confinement lasting anywhere from a few minutes to a few …  Read more

In mice, H2 and Ly49h genes determine natural resistance to cytomegalovirus infection by alternate mechanisms. We are interested in MA/My, an inbred strain that is resistant to MCMV infection despite the absence of Ly49H receptor and the presence of a haplotype highly related to the MCMV-susceptible strains 129 and FVB/N. Therefore, it is interesting to study its genetic basis of resistance to MCMV infection. In this study, we have identified Cmv1rm, a new resistance allele conferring resistance in MA/My. We have demonstrated by statistical analyses that both H2 and NKC genes are important and that their genetic interaction is necessary …  Read more

Pitx2 is a homeodomain transcription factor. Three functional protein isoforms are encoded by the Pitx2 gene that differ only in their N-terminus. Functional studies have demonstrated that the Pitx2c isoform is the most downstream component of the left-right patterning cascade that is responsible for positioning the internal organs relative to the midline. In all vertebrates, mRNA for the Pitx2c isoform is expressed asymmetrically in the left lateral plate mesoderm and in organs that become asymmetrically positioned. A Pitx2c isoform specific antibody was created and used to determine the pattern of Pitx2c protein expression in the chick embryo. Pitx2c protein expression …  Read more

My thesis is a collection of non-fiction and fictional narratives focused on domestic space and its impact on father-daughter relationships and vice versa. In all of the narratives the notion of a house under renovation serves as a vehicle for the figurative tension between members of the family and family space. The narratives offer no internal markers to indicate whether they are fiction or non-fiction, which demonstrates my conviction that only factors external to the text---relation to fact or to imagination---can determine a narrative's status as fiction or non-fiction. The required afterword to my narratives discusses the theoretical problem of …  Read more

The history of collection at the National Gallery of Canada, the Art Gallery of Ontario and the Montreal Museum of Fine Arts, illustrates concepts of race in the development of museums in Canada from before Confederation to today. Located at intersections of Art History, Museology, Postcolonial Studies and Native Studies, this thesis uses discourse theory to trouble definitions of nation and problematize them as inherently racial constructs wherein 'Canadianness' is institutionalized as a dominant white, Euro-Canadian discourse that mediates belonging. The recent reinstallations of the permanent Canadian historical art galleries at the National Gallery of Canada, the Art Gallery of …  Read more

Chronic bladder pain is becoming more and more prevalent and yet there is a lack of effective treatment because there is so little known about the mechanisms causing this type of pain. A possible etiology of chronic bladder pain is persistent inflammation. It has been proposed that inflammation initiates neurological changes in the bladder and CNS which could lead to sensitization of the bladder to cause chronic pain and frequency. Both autonomic and sensory innervation changes in the periphery can lead to hyperalgesia and allodynia, thus we have chosen to look for autonomic and sensory innervation changes that occur in …  Read more

The present study examined the relationship between several risk and protective variables associated with problem gambling, substance abuse, and other multiple risk-taking activities by adolescents. With the goal of identifying protective factors that prevent youth from escalating from social gambling to serious problem gambling, this research examined the relationship between family cohesion, school connectedness, coping and adaptive behaviours, mentor relationships, achievement motivation, involvement in conventional organizations, and the development of three health-compromising outcomes---youth problem gambling, substance abuse, and involvement in multiple risk-taking behaviours (e.g., smoking, unsafe sexual activity, and reckless driving). The sample consisted of 2,179 students, ages 11 to …  Read more

Plant-herbivore interactions play a significant role in the structure and functioning of ecosystems. Co-evolutionary theory suggests that plant defenses evolved due to herbivores and herbivore pressure can shape the genetic composition of their food resources. We used interactions between North American porcupines (Erethizon dorsatum) and trembling aspens ( Populus tremuloides) as a system to investigate this theory's important assumption that herbivores select food sources based on genetically controlled traits. We confirmed that porcupines exhibit intra-specific food selection and that this is linked to the genetic composition of the aspens. We also demonstrated that variation in phenolic glycosides and condensed tannins …  Read more