McGill University Thèses et mémoires publiés en 2005

This study examines the relationship between parenting styles, family environment, and gambling behavior among 1,203 CEGEP students in the greater Montreal area. Participants reported on their past year gambling behavior and their perceptions of their family environment. Their perceptions of their parents' pattern of parenting were also reported, and are identified based upon Buri's (1991) and Baumrind's (1971) authoritarian, authoritative/flexible, and permissive parenting styles. Results showed that parenting styles indirectly influence problem gambling behavior via family environment. Poor family environments, characterized by high levels of conflict and low levels of cohesion, were found to significantly increase the likelihood of gambling …  Read more

This thesis analyzes Viktor Pelevin's Chapaev i Pustota (1996) from the perspective of its (extra-)literary context, and status as a threshold text on various levels. It argues that through the expression of satire, parody, and nostalgia, Pelevin's novel exemplifies and transcends the threshold between the Soviet and post-Soviet literary narrative. Against the background of various comparison texts, by such precursors and contemporaries as Kaledin, Makanin, Petrushevskaia, P'ietsukh, Sorokin and Tolstaia, Pelevin's novel is shown both to conform with and diverge from the (post-)glasnost' literary text. Common features on the levels of theme and motif are identified, in order to establish …  Read more

Although Great Powers are often thought to be the most influential actors in terms of international arms control efforts, during the 1990s Canada showed itself capable of successfully leading several arms control initiatives. This research sets out to (a) explain why Canada has been able to enjoy these successes while other recent Canadian arms control leadership efforts have failed, and (b) further the abstract thinking around Canadian foreign policy. This is done by introducing the Identity Management model of arms control to explain the process by which Canadian arms control processes succeed or fail, and testing it against four post-Cold …  Read more

This thesis is devoted to the studies of self-assembled InAs quantum dots (QD) by low-temperature Atomic Force Microscopy (AFM) in frequency modulation mode. Several spectroscopic methods are developed to investigate single electron charging from a two-dimensional electron gas (2DEG) to an individual InAs QD. Furthermore, a new technique to measure the absolute tip-sample capacitance is also demonstrated. The main observables are the electrostatic force between the metal-coated AFM tip and sample as well as the sample-induced energy dissipation, and therefore no tunneling current has to be collected at the AFM tip. Measurements were performed by recording simultaneously the shift in …  Read more

The Native peoples of North America still confront the challenges of lingering colonial cultural imperialism. One such challenge is that of Native education, and its unfortunate management by the European-descended political powers. Using tactics such as assimilation, segregation and integration, the establishment used schooling as a blunt tool to solve the so-called "Indian problem"---that is, the assimilation of the Native population into the European way of life. The results were predictably tragic; the current education system is still perceived as a tool of colonization by many Natives. After so many failed attempts, policy-makers are finally looking to return to the …  Read more

The goal of conformal radiation techniques is to improve local tumor control through dose escalation to target volumes while at the same time sparing surrounding healthy tissue. Accurate target volume delineation is essential in achieving this goal to avoid inadequate tumor coverage and/or irradiation of an unnecessary volume of healthy tissue. Respiratory motion is known to be the largest intra-fractional organ motion and the most significant source of uncertainty in treatment planning for chest lesions. A method to minimize effects of respiratory motion is to use four-dimensional (4D) radiotherapy. A novel scanning procedure for 4D CT data acquisition is described …  Read more

The push for educational reform in the province of Quebec, Canada has brought to the foreground many ideas about what needs to be done to improve the learning experience of students. While there has been some movement in the primary grade levels, change in the secondary level is still in its infancy. There are some teachers, however, in high schools who have been on the cutting edge of educational reform. The purpose of this study is to look at participation within a secondary classroom where the philosophy of the reform is being acted upon. The study, qualitative in design, is …  Read more

With the advent of XML as a standardized data representation model, the need has emerged to store, retrieve and update XML data. A new breed of databases called native XML databases have been designed from the ground up to perform such actions. McXML is an example of a native XML database. McXML was developed at McGill University and it specializes in updating XML. We have designed and developed a page based storage manager for McXML, which replaces the existing plain text manager. The new storage manager allows efficient persistence, retrieval and update of XML data using complex data structures. The …  Read more

This thesis presents a new multi-projector front-projection display system that can be used for an immersive environment. The implementation of such a system faces new challenges that were avoided by design in CAVE-like systems. These include removing the perspective warping from misaligned projectors and adjusting the intensity to create a uniformly lit display in regions where projectors overlap. Also, when the display is in use, occluding objects between the projector and the display surface cause shadows on the display that must be removed. These three issues have been addressed in this work based in part on algorithms from the field …  Read more

A layered graph drawing is a two-dimensional drawing of a combinatorial graph in which the vertices lie on a given set of horizontal lines. Such drawings are used in application domains such as software engineering, bioinformatics, and VLSI design. In addition to being layered, drawings in these applications may also satisfy other constraints, for example bounds on the number of edge crossings. The problems related to obtaining these drawings are almost always NP -hard, so, in this thesis, we investigate restricted versions of these problems in order to find efficient algorithmic solutions that can be used in practice. As a …  Read more

Computational fluid dynamics is increasingly used as an analysis and simulation tool in research and industry. Mesh generation remains a major challenge, in particular for turbulent flow simulations, as it can be very difficult and time-consuming to produce a good mesh that will produce accurate results. Mesh adaptation schemes have been developed to help improve the solutions obtained and facilitate the mesh generation process. This work expands the Y+ correction scheme within an existing 3-D anisotropic mesh adaptation module for turbulent flow simulations developed at the McGill CFD Lab. First, the Y+ correction scheme is improved for structured layers of …  Read more

This dissertation examines two controversies involving paintings of the female nude by artists Debora Arango and Carlos Correa during a period of political crisis in Bogota (Colombia) in order to open the political to cultural analysis and thus shed light on scenarios of change in the 1930s and 1940s. Unpacking the controversies lends insight into the unique ways in which modernity, the body, its representations, sexuality, gender and politics came together in Colombia during this period. Such an approach also shows that modernity in Colombia involved shifts in religious and secular frames of sense-making and morality. This dissertation argues that …  Read more

Angiogenesis is the formation of new blood vessels by sprouting from existing vessels. In order for new blood vessels to invade the surrounding tissue, the extracellular matrix must be degraded and subsequently remodeled. Fibulin (fbln)-5 (DANCE, EVEC) is an elastin and integrin binding extracellular matrix protein that is expressed strongly throughout the cardiovascular system during development and is re-expressed during vascular injury. Recently, an increase in the number of cutaneous blood vessels was observed on the posterior surface of the abdominal wall of the fbln5-/- mouse. In the present study, the role of fibulin-5 as an anti-angiogenic factor was investigated …  Read more

UDDI registries are intended to become the world-wide lookup mechanism for web services. As such, they have to provide low response time, high throughput, high availability, and access to accurate data. Data replication is a key technology to satisfy such requirements. However, replication requires proper coordination of updates. Various replication strategies favor different subsets of the performance metrics. In this thesis, we have a closer look at two different replication strategies. One follows the UDDI specification; the other uses a middleware-based replication tool. We have integrated both approaches into an existing UDDI registry in a modular way. The thesis provides …  Read more

Nod factors, lipo-chitooligosaccharides (LCOs), are rhizobial signal molecules important in the establishment of nodule formation, leading to atmospheric dinitrogen fixation in legume-rhizobium symbioses. Recently, LCOs were also found to regulate other plant processes. We demonstrated that, at 10 -6 M, four LCOs produced by Bradyrhizobium japonicum enhanced soybean seed germination. Evaluation of G-protein inhibitors showed that U-73122, a phospholipase C inhibitor, also increased soybean seed germination, similar to the increase by LCO NodBj-V(C18:1 MeFuc), indicating different mechanisms for the plant perception to LCOs for nodule initiation and seed germination. This was confirmed as LCOs were not able to break dormancy …  Read more

Background. Fatigue is a debilitating consequence of lung cancer and its treatments. Reviewing the literature in cancer-related fatigue provides few etiological factors, making evidence-based interventions limited. In this study, previously identified factors as well as muscular and cardiorespiratory function were assessed as potential contributors to fatigue in stages 3A/B and 4 NSCLC patients. Methods. Participants were evaluated by a physical therapist within the McGill Cancer Nutrition and Rehabilitation Program. Performance-based measures of physical function [upper limb strength and endurance (Jamar dynamometry), lower limb strength (30sec chair rise), cardiorespiratory function (2 minute walk - 2MW)] and a symptom questionnaire (Edmonton Symptom …  Read more

Zinc cluster proteins are a major class of transcriptional regulators in Saccharomyces cerevisiae. This protein family includes Uga3 and Dal81, which are both required for the activation of genes involved in the catabolism of gamma-aminobutyrate (GABA). We discovered that the region of Uga3 encompassing amino acids 130 to 300 likely corresponds to the regulatory domain of the protein. We also determined that both the region encompassing amino acids 300 to 350 and the C-terminus of Uga3 are required for activation. Additionally, activation by Uga3 can occur in strains unable to completely degrade GABA or lacking the GABA permease Uga4. Uga3 …  Read more

Relationships between cardiovascular and neural activities were explored in 11 patients with intractable epilepsy. Using depth electrodes, we examined the cardiovascular response to direct electrical stimulation, and monitored EEG activity during simple physical and mental challenges known to elicit a cardiovascular response. Stimulation was most commonly performed in four regions: the hippocampus, amygdala, and the supra- and sub-callosal anterior cingulate cortex (ACC). While increases in systolic blood pressure (SBP) in response to electrical stimulation of these brain regions were observed with equal frequency, a striking cardiovascular response was observed in one patient when stimulating the supracallosal ACC (an increase in …  Read more

A fractional iterative channel estimation and data detection algorithm is proposed for frequency selective, quasi-static MIMO channels. It is shown that due to the correlation of the noise samples after pulse matched filtering and sampling, the complexity of the derived receiver, based on the Expectation-Maximization (EM) algorithm with fractional sampling, is the same as that of the ML receiver, which requires an exhaustive search. It is shown that by using a noise whitening filter to whiten the noise samples, the algorithm can be efficiently implemented using the Viterbi algorithm instead of using an exhaustive search technique. Due to spectral zeros …  Read more

Electrochemically-induced changes in surface stress at the solid-liquid interface are measured using a differential cantilever-based sensor. The simultaneous, in situ measurements of the current (charge) and interfacial stress changes are performed by employing an AFM cantilever as both the working electrode (in a conventional three-probe electrochemical cell configuration) and as the mechanical transducer (bending of the cantilever). The custom-built instrument achieves a surface stress sensitivity of 1x10-4 N/m and a dynamic range of 5x105. Combining electrochemistry with cantilever-based sensing provides the extra surface characterization capability essential for the interpretation of the origin of the surface stress. The objective of the …  Read more

An association has been observed between the catechol-O-methyltransferase (COMT) gene, the predominant means of catecholamine catabolism within the prefrontal cortex (PFC), and neuropsychological task performance in healthy and schizophrenic adults. Since several of the cognitive functions typically deficient in children with Attention Deficit Hyperactivity Disorder (ADHD) are mediated by prefrontal dopamine (DA) mechanisms, we investigated the relationship between a functional polymorphism of the COMT gene and neuropsychological task performance in these children. Furthermore, since methylphenidate (MPH), the primary pharmacological drug in ADHD, may exert its effects, at least in part, through PFC dopaminergic pathways, we investigated the relationship between the …  Read more

The adsorption behaviour of trace metals in soil may provide us with a way to more accurately predict and assess the toxicity of metals in the environment. This thesis reports efforts to apply surface complexation modeling to agricultural and forest soil and to relate model parameters to common soil properties. This study considered Ca, Cd, Cu, Pb and Zn but the methods here could be applied to other metals. In Chapter 2, the surface charge and adsorption behaviour of a set of Ap horizons was characterised using back-titration and batch adsorption techniques. With the objective of simplifying the application of …  Read more

Karoshi, or death from overwork, is a tragic modern work event. Continuous occurrence of karoshi in Japan offers an opportunity to reconsider the contemporary working environment, and especially the workers' compensation system. Strongly bound by the traditional notion of work accident, the Japanese workers' compensation system has shown difficulty handling karoshi cases. This fact calls into question the adequacy of the current workers' compensation scheme in the work environment it is meant to oversee. To analyze the issue, this thesis will use a comparative law method. The basis of comparison will be Ontario, Canada, which shares a system similar to …  Read more

One-, two- and three-dimensional transient heat transfer finite element models are developed to simulate the resistance welding process of pre-consolidated unidirectional AS4 carbon fibre reinforced Poly-ether-ether-ketone (APC-2/AS4) laminates with a metal mesh heating element, in a lap-shear configuration. The finite element models are used to investigate the effect of process and material parameters on the thermal behaviour of the coupon size welds, yielding to a better understanding of the process. The 1-D model determines: (a) the importance of including the latent heat of PEEK, and (b) the through-thickness temperature gradient away from the edges, for different tooling plate materials. The …  Read more

Duma pro Slipykh is a composition for solo baritone, 12-part mixed choir and small chamber orchestra, lasting approximately 17 minutes and 30 seconds. The work sets excerpts from two Ukrainian poems: Mykola Bazhan's Sliptsi (1929) and Wolodymyr Tsybul'ko's Yanholy i Vovky (1996). Excerpts from both poems were layered in various ways to form the text of the piece. The simultaneous performance of multiple excerpts with common elements and themes was devised to emulate the frenetic energy and angry frustration the poets were trying to express in their poems. Although nearly seventy years separate the two poems, the general themes of …  Read more

The Glucocorticoid receptor (GR) is one of many steroid hormone receptors. It controls broad physiological gene networks, confers pathological effects in a range of disease states, and offers an excellent target for therapeutic intervention. Therefore, it is necessary to better understand the mechanisms of GR regulation. In particular, we are interested in better understanding the protein-nucleotide interactions (transcription factors interacting with transcription factor binding sites). Upon glucocorticoids-hormone binding, the GR forms a protein-nucleotide interaction with a specific transcription factor binding site known as a glucocorticoid response element (GRE). This research has employed three different but complementary bioinformatics approaches to identify …  Read more

An association between body mass index (BMI) and caesarean section has been documented in the literature in developed countries. The causal factors leading to this association are not known, therefore it is unknown whether this association could be extended to developing countries. This study will examine BMI as a risk factor for caesarean section in women in a developing country. This study included a cohort of 290,124 births in Uruguay, from the years 1992 to 2001, and a cohort from Pelotas, Brazil with 8,475 births, from 1982 and 1993. Three statistical methods were used to deal with missing data in …  Read more

The Rho GTPases are members of the Ras superfamily of small monomeric GTP binding proteins that regulate multiple cellular processes affecting both cell proliferation and cytoskeletal dynamics. They are positively and negatively regulated by the guanine nucleotide exchange factors (GEFs) and the GTPase-activating proteins (GAPS), respectively. In principle, extracellular signals such as growth factors and other agents bind to plasma membrane receptors and modulate Rho GTPase function through intracellular mechanisms that affect GEF or GAP activities. There is now compelling evidence that both receptors and cytoplasmic proteins implicated in Rho GTPase signaling are modulated by post-translational modifications such as phosphorylation. …  Read more

Divided into six chapters, our thesis examines the translation of Evgenyi Onegin, a novel in verse by Aleksandr Pushkin, in France and Japan in the 20th century. In Chapter 1, we introduce our methodological approach, including the eight elements of our translation analysis: the by-who, the who, the what, the for-who, the when, the why, the where, and the how. In Chapter 2, after a brief biography of the Russian poet, we examine his central work Evgenyi Onegin, and its unique structuro-phono-semantic synthesis. The first French mention of Pushkin was in the 19th century, and the 'transfer-related discourse' of that …  Read more

The Ras proteins (H-Ras, N-Ras and K-Ras4B) are monomeric GTP-binding proteins that play key roles in cell regulation. It has been proposed that correct plasma membrane localization of the Ras proteins requires 'two signals', the processed farnesylation sequence and an adjacent palmitoylation site(s) or polybasic sequence. First, to investigate potential proteinaceous binding partners for the K-Ras4B targeting sequence at the plasma membrane, an in vivo crosslinking analysis was carried out. Consistent with current suggestions that K-Ras4B interacts via electrostatic interactions with plasma membrane lipids, no indication of a K-Ras4B plasma membrane binding partner was found. In the second portion of …  Read more

This study examined the relationship between residential environment and subjective quality of life (QOL) for individuals with mental illness. Demographic variables impacting QOL were also examined. The Wisconsin Quality of Life Index---Canadian Version (CaW QLI, Diaz & Mercier, 1996) was administered to a total of 46 participants and was used to assess the QOL of individuals living in a supported residential environment as compared to individuals living in other types of environments. The major findings were: (1) psychiatric consumers/survivors in the supported residential environment reported higher QOL scores in 4 of the 9 domains examined; (2) residents living in a …  Read more

This study examined the use of language in the development and implementation of mental health policy. It focused on the current discourse of mental health reform in Ontario as it related to individuals with a mental illness and who are in conflict with the law. Using a qualitative design, informed by critical inquiry and a postmodern perspective, the researcher explored administrative perceptions of the accomplishments and challenges faced at different levels of the mental health and criminal justices systems in Ontario. The participants' understandings of the provincial mental health reform policy, Making it Happen, and the extent they felt that …  Read more

The bandwidth bottleneck present in the access level of optical networks stimulated research, leading to novel topologies, including passive optical networks. In parallel, the increasing processing power of digital systems led to a similar bottleneck in chip-to-chip and board-to-board communications. Guided-wave optical interconnection on printed-circuit boards is viewed as a potential solution. This thesis outlines the design, implementation, and testing of a vertical-cavity surface-emitting laser (VCSEL)-based optical transmitter in 0.18mum CMOS usable for both applications. Optical transmitter architectures are reviewed and a suitable topology is proposed. The implementation includes an original dual power-rail layout for reduced power consumption. A detailed …  Read more

This study seeks to explain the relationship between civic associations and attitudinal social capital---norms of trust and reciprocity---within the context of an authoritarian state. In contrast to many post-industrial nations, Nigeria boasts a vibrant civil society but seems to possess little attitudinal social capital. A deeper understanding of this relationship is offered by considering how an association's structure influences members' attitudes and how this relationship is impacted by a repressive regime. These relationships are tested using both statistical data and a qualitative study of three associations. The findings support the hypothesis that certain structural characteristics are more conducive to the …  Read more

Knowledge-based Cascade-correlation is a neural network algorithm that combines inductive learning and knowledge transfer (Shultz & Rivest, 2001). In the present thesis, this algorithm is tested on several real-world and artificial problems, and extended in several ways. The first extension consists in the incorporation of the Knowledge-based Artificial Neural Network (KBANN; Shavlik, 1994) technique for generating rule-based (RBCC) networks. The second extension consists of the adaptation of the Optimal Brain Damage (OBD; LeCun, Denker, & Solla, 1990) pruning technique to remove superfluous connection weights. Finally, the third extension consists in a new objective function based on information theory for controlling …  Read more

This study addresses the question of the nature of indigenous people's connection to the land, and the implications of this for articulating these connections in legal arenas where questions of Aboriginal title and land claims are at issue. The idea of 'place' is developed, based in a phenomenology of dwelling which takes profound attachments to home places as shaping and being shaped by ontological orientation and social organization. In this theory of the 'senses of place', the author emphasizes the relationships between meaning and power experienced and embodied in place, and the social systems of property and territory that forms …  Read more

The Defense Style Questionnaire (DSQ) is a self-report instrument designed to measure defensive functioning and coping styles. Originally developed by Bond and colleagues (1983), the questionnaire has been researched extensively. The present investigation sought to determine the factor validity of the newly developed DSQ-60 (Trijsburg, Bond & Drapeau, 2003) in a sample of English-speaking university students (n = 305) and French-speaking university students (n = 212). Using both exploratory and confirmatory factor analyses, three factors, or defense styles were revealed: image distorting, affect regulating, and adaptive. Cronbach's alpha for the three styles was .64, .72, and .61, respectively. Results are …  Read more

The processability of a resin in film blowing is strongly influenced by its flow behavior in extension. In this study, the suitability of the Sentmanat Extensional Rheometer (SER) and of a novel tester for polyethylene film resins was evaluated. The SER, which subjects the resin to simple extension, is simple and fast to use, requires a small quantity of sample and gives reliable data that can be used to detect differences in molecular weight, molecular weight distribution and levels of long-chain branching. The data are also related to the stability of the bubble in film blowing. The tester, on the …  Read more

This dissertation sets out to determine the social function of paraenesis ("moral exhortation") within Valentinian Christianity. In order to explicate this social function, this study places the discussion within the context of ancient rhetorical practices of ethical admonition; i.e., how did paraenetic discursive practices act as rhetorical devices for affecting social formation? In order to establish the function of paraenesis, it is necessary to engage both literary and social aspects of the paraenetic genre. The latter is most challenging, given the methodological difficulties inherent in moving from textual context to socio-historical reconstruction of the situation behind a text. To address …  Read more

This thesis is an overview of the historical context in which the church of Christ the Redeemer (Sant'Apollinare Nuovo) in Ravenna, Italy, was erected. It explores the forces responsible for shaping the church at the time of its construction and decoration in the sixth century. The basilica had gained popularity of usage as a model for the Christian Church in the West by this time. This thesis further explores the conclusions put forth by scholars that the basilica was the forum in which the transition of architectural imperial symbolism from the pagan empire to the new Christian Church took place, …  Read more

We examine whether the precepts of what have been termed 'close', 'intimate', or, more specifically, 'communal' relationships in Social Psychology may be communicated via Web site content and whether this positively impacts Site-Loyalty. We introduce a variable called Site-Communality defined as the extent to which Web site content signals that a company's relationship with its customers goes beyond the formal, 'tit for tat' business dealings that are typically expected from purely commercial exchanges, and instead, more closely abide by the norms and behaviours evocative of friendships and/or family relations. We develop multi-dimensional measures of Site-Communality and Site-Loyalty. Using Structural Equation …  Read more

Trembling aspen (Populus tremuloides Michx.) were observed growing along roads far north from the area where it dominates, in sites dominated by black spruce (Picea mariana (Mill.) B.S.P.) forests. This study examined the distribution of aspen at an early development stage and the conditions in which they are growing in a black spruce/feathermoss forest type in northwestern Abitibi, Quebec six years following harvesting. In this region, aspen are appearing in logged and burned areas that had been previously dominated by black spruce. The relationship of aspen growth with Ca availability and mineral soil access is the main focus of the …  Read more

This thesis presents a statistical learning framework for inferring geometric structures from images. Specifically, the proposed framework computes dense range maps of location sin the environment using only intensity images and very limited amount of range data as an input. This is achieved by integrating and analyzing the statistical relationships between the visual data and the available depth on terms of small patches. The scientific issue is to represent this correlation such that it can be used to recover range data where missing. Markov Random Fields are used as a model to capture the local statistics of the intensity and …  Read more

The activation of death receptor Fas (CD95/APO1) triggers apoptosis inducing caspase activation by direct (extrinsic) and mitochondria dependent (intrinsic) pathways. Mitogen activated protein kinases (MAPK), which include p38, JNK and ERK kinases, are also activated during Fas signaling and are known to either positively or negatively regulate apoptosis. Chemical inhibition of JNK (SP600125) and p38 (PD169316) sensitize tumor cells to Fas mediated apoptosis. I studied Fas mediated apoptosis in Jurkat cells and in some experiments HeLa cells. PD169316 is less potent than SP600125 and attenuates the effect of the later when present together. PD169316 inhibits two isoforms of p38 which …  Read more

This thesis describes different bit allocation schemes and their performances when applied on coding line spectral frequencies (LSF) using the GMM-based coder designed by Subramaniam and a simple image transform coder. The new algorithms are compared to the original bit allocation formula; the Pruning algorithm used by Subramaniam, Segall's method and the Greedy bit allocation algorithm using the Log Spectral Distortion and the Mean-Square Error for the LSF quantizer and the Peak Signal-to-Noise Ratio for the image coder. First, a Greedy level allocation algorithm is developed based on the philosophy of the Greedy algorithin but, it does so level by …  Read more

This thesis is a literary analysis of two novels, Comme le bon pain (2001) by Mariama Ndoye and Cendres et braises (1994) by Ken Bugul. It examines the representation of Islam in relation to African women's identity, with particular emphasis on its relationship with the postcolonial context of francophone West Africa. Chapter I reviews the emergence of African francophone literature by women authors and the trends of criticism that developed as a result of it. It also presents the theoretical framework of this research, namely feminist and postcolonial theories inspired by Frantz Fanon and African women theorists. Chapter II of …  Read more

Ovine (strains 9L and 3384Y) and bovine (strains 649, 2336 and 8025) isolates of Histophilus somni were investigated for their ability to acquire iron from haemoglobin (Hb). Bovine isolates were capable of utilizing bovine, but not ovine, porcine or human Hb as a source of iron. Ovine isolates could not obtain iron from Hb. Bovine isolates bound bovine, ovine, and human Hbs by means of the same iron-repressible receptor(s) and produced a ~120-kDa iron-repressible, outer membrane protein. Using PCR approaches, an iron-regulated operon containing hugX and hugZ homologues and a gene (hgbA) that encodes a TonB-dependent, Hb-binding proteins were identified …  Read more

An enduring puzzle of race relations in Brazil is that for most of the 20th century this topic was conspicuously absent from politics, in spite of deep-rooted inequalities between whites and non-whites. The ideology of "racial democracy" effectively depoliticised the issue until the late 1990s, when a wide-ranging programme of affirmative action policies for Afro-Brazilians was implemented. Beginning with the idea that the myth of racial democracy functioned as an ideological hegemony in the Gramscian sense, this dissertation seeks to explain the process through which public policies ceased to reflect this hegemonic ideology, and instead began to represent a counterhegemonic …  Read more

The biological degradation of the synthetic aliphatic/aromatic co-polyester Ecoflex(TM) (BASF) by 30 strains of hydrolase-producing soil bacteria, fungi and yeasts was investigated at moderate environmental conditions. Previous studies had shown that these materials could be degraded. These studies were done uniquely in compost or by axenic compost isolates, and under thermophilic conditions, but it is likely that most of this material will be found in sites at more moderate conditions. Thus, a screening procedure was developed to assess the biodegradability of the co-polyester at ambient environmental conditions. The screening also allowed for the investigation of the mechanism of biodegradation in …  Read more

Deeper understanding of the factors controlling stable isotopic signatures of aquatic organisms of all trophic levels is required if we are to properly use them in food web studies and as environmental indicators. The present field study conducted in the Ste. Marguerite River system, Quebec, compared periphyton signatures found in eight reaches (sections of a river/tributary) each composed of a series of sites with different flow regimes. Similar to patterns found in the laboratory, periphyton delta13C significantly decreased with increasing water velocity. In addition, periphyton biomass positively affected periphyton delta13C. Isotopic fractionation in favour of 12C by the periphyton communities …  Read more