VictorJuiz/thesis huggingface dataset:
Descriptions and phylogenetic systematics of Myxobolus spp. from cyprinids in Algonquin Park, Ontario

Eight species of 'Myxobolus,' of which five are described as new and two are redescribed, were collected from cyprinids in Algonquin Park. The evolutionary relationships among these eight species using morphological and partial ssu-rDNA sequence data were studied. The resulting trees allowed for the evaluation of spore morphology, host specificity, and tissue tropism, criteria traditionally used in species identification. These criteria, recently criticized as creating artificial rather than natural taxonomic groupings, were evaluated for their reliability in the systematics of the species examined. The data showed that distantly related species often infect the same host and tissue, and closely related species often occur in different hosts. Morphologically similar species are more closely related to each other and the taxonomy based on spore morphology is consistent with the phylogenetic relationships. These results suggest that spore morphology is better than host and tissue specificity for determining evolutionary relationships and species identity.
Multiple levels of regulation of the G(1) transcription factor SBF

In all eukaryotic cells the commitment to enter the cell cycle in late G1 is a highly regulated event characterized by a burst of gene transcription. In budding yeast, the heterodimeric transcription factor SBF is composed of Swi4 and Swi6 and is required for the induction of a large group of genes early in the cell cycle. In this thesis, I describe a novel set of mechanisms that regulate and modulate the activity of SBF. During the cell cycle, Swi4 binding to DNA is a highly regulated event restricted to only late M and G1 phases. Through a series of genetic and biochemical experiments, I determined that the inhibition of Swi4 binding to SCBs in the absence of Swi6 is intrinsic to Swi4 and is mediated through the C-terminal region of Swi4. Further, the C-terminal region of Swi4 could interact 'in vitro' with the N-terminal DNA-binding domain of Swi4. My data suggest that intramolecular interactions with the C-terminal region of Swi4 physically prevent the DNA-binding domain from binding SCBs. Upon the addition of Swi6, the interaction of the C-terminal region of Swi4 with Swi6 alleviates this inhibition, allowing Swi4 to bind DNA. SBF-dependent transcription involves the cyclin-dependent kinase Cln3-Cdc28. However, in the absence of Cln3, SBF-dependent transcription still occurs. I present direct evidence linking the 'PKC1'-MAPK pathway to SBF activation. Further, I found that activation of Slt2 by heat shock leads to the transcriptional induction of the SBF-dependent genes 'PCL1' and 'PCL2' but not 'CLN1' and 'CLN2'. Through a series of genetic, biochemical and DNA microarray analyses I show that Slt2 likely modulates the activity of Swi4 to regulate the transcription of 28 genes, many of which are not cell cycle-regulated or SCB-regulated. This work suggests that the 'PKC1'-MAPK pathway may utilize Swi4 outside of the cell cycle to elicit part of the transcriptional response necessary for cell integrity. My experiments also suggest that the heat shock expression of Slt2/Swi4-dependent genes may not require Swi6.
Parallel job scheduling on heterogeneous networks of multiprocessor workstations

Parallel job scheduling has been heavily studied on various architectures, from vector supercomputers to networks of workstations. A common assumption of this previous work has been that all processors in the system have equal processing power. We investigate parallel job scheduling on 'heterogeneous ' networks of multiprocessor nodes, where the machines in the network can vary in 'processor speed' and 'node size' (number of processors per node). Two dynamic scheduling policies and two adaptive scheduling policies are simulated in this framework. We provide some evidence that a network's ' coefficient of variation' (standard deviation over mean) of processor speed or node size is a good predictor of job mean response time for these algorithms. As well, processor-speed heterogeneity is found to have a greater effect on job mean response time than node-size heterogeneity. In some cases, the adaptive algorithms can outperform the more flexible dynamic algorithms due to job imbalances created by dynamically reassigning processors.
A five-year longitudinal study of spelling and writing development, differences and similarities in L1 and L2 elementary students

Spelling and writing samples collected over a four year period were analyzed to examine children's progression in spelling and written composition. Their performance on standardized spelling tests was examined with a focus on the development of spelling skill and strategy use. Their progression in written composition was analyzed with a focus on the development of spelling, story ideation, vocabulary complexity, punctuation, capitalization and composition length. Comparisons were made among the samples of children who spoke English as a first language (L1), with children who spoke English as a second language (L2). The relationship between processing measures collected in kindergarten, and later spelling and writing ability was also examined with a focus on do similarities and differences that were found between L1 and L2 learners. The results indicated that measures of phonological processing and early literacy skill collected in kindergarten were predictive of later spelling and writing development, and that the L1 group performed slightly better than their L2 counterparts on the battery of processing measures administered in kindergarten. Measures collected at the beginning of kindergarten before instruction in a balanced literacy program that included training in phonological awareness and alphabet coding were more predictive than measures collected at the end of kindergarten, after the program. Despite these early differences in their processing profiles, there were no statistically significant differences between the spelling and writing samples of the L1 and L2 groups across Grades 1 to 4: the two groups followed similar developmental trajectories.
Cancer incidence, mortality and survival among status Indians in Ontario, 1968-1991

Objectives. The objectives of this thesis were to describe cancer incidence, mortality and survival among Status Indians in Ontario and to compare their experience with that of the general population of Ontario. Methods. The data were the result of a record linkage project in which records from the Indian Registry, the Ontario Cancer Registry, the Manitoba Cancer Registry and the All Cause Mortality File for Ontario were linked. Incidence and mortality rates and ratios, time trends and survival were computed. Results. Status Indians had significantly lower cancer incidence and mortality rates compared with the general population for most cancer sites. For Status Indians, incidence and mortality rates for many sites increased over time. Status Indians experienced significantly poorer survival for all sites combined and for some of the most common cancer sites compared with the general population. Conclusion. Additional information on risk factors for cancer among Status Indians is required. Additional research is also required to understand why Status Indians have poorer survival compared with the general population.
Towards the generation and characterization of arylamine N-acetyltransferase-deficient mice

N-acetyltransferases (NATs) are enzymes of phase II drug biotransformation that metabolize aromatic amine-containing compounds found in clinically useful drugs, in environmental pollutants and in cooked foods. Experimental studies have shown that NATs have both detoxifying and toxifying roles in the body. Presently available animal models, while useful, have not yet truly revealed the overall or relative importance of mouse N-acetyltransferases in toxicology and disease. To avoid some of the inherent weaknesses in these studies and to more clearly understand the role of NATs in drug induced toxicity and carcinogenesis, the overall goal of this research was to create and characterize novel NAT deficient mouse strains. Our first objective was to produce a NAT deficient mouse strain by gene targeting using R1 ES cells by: (1) introducing the mouse NAT1/mouse NAT2 and mouse NAT3 gene targeting vectors into R1 ES cells, (2) designing PCR and Southern blotting screening methods to enable the detection of the mouse NAT targeted knockouts. Our second objective was to produce isozyme specific anti-mouse NAT antibodies for use in characterizing these strains by: (1) designing and constructing three mNAT-GST fusion protein antigens, (2) expressing the fusion proteins in bacteria and (3) purifying and injecting the antigens into rabbits to produce isozyme specific anti-mouse NAT antibodies. (Abstract shortened by UMI.)
Fibronectin-rhamm interactions, which are required for cell motility, regulate podosome formation

Invadopodia or podosomes have been identified as sites for the local release of matrix metalloproteinases required for the initiation of cell motility and invasion. In this study, we confirm that the cell surface expression of the hyaluronan receptor RHAMM occurs transiently and report that fibronectin (FN) upregulates this expression by stabilizing the retention of RHAMM within podosomes. Further, anti-RHAMM antibodies block podosome formation suggesting FN-RHAMM interactions play a key role in the organization of these structures. RHAMM binds directly to the carboxy-terminal heparin-binding domain of FN via an imperfect leucine zipper motif encoded by exon 3. Peptides mimicking this sequence disrupt FN-RHAMM interactions resulting in both the inhibition of podosome formation as detected by cortactin and p130CAS staining within these structures and the reduction of random cell motility. Overexpression of RHAMM modifies the FN-induced tyrosine phosphorylation profile of proteins; notably, cortactin phosphorylation is enhanced. However, exon 3-mimicking peptide could not block these RHAMM-induced phosphorylation changes. Thus, we conclude that cell surface RHAMM plays a structural role in controlling podosome integrity independent of phosphotyrosine signaling.
Conduit versus resistance blood vessels, adrenoceptors and nitric oxide

Local regulation of hemodynamic control is a complex mechanism that employs a number of biochemical processes (including adrenoceptor control and Nitric Oxide (NO) modulation) depending on the vascular bed and function. The nature of adrenoceptors and nitric oxide modulation were, therefore, investigated in two distinct types of blood vessels with different function. Third generation rat mesenteric arteries (50 to 200$\mu$m diameter) and descending thoracic aorta were selected as resistance and conduit arteries respectively. These were dissected and mounted in a microvessel chamber or a standard (10ml) organ bath. The preparations were allowed to equilibrate, and Thereafter, a series of experiments were performed to examine adrenoceptor characterization and the role played by nitric oxide in the vascular response. Specifically the effects of several antagonists were inspected against the agonist response. These studies confirm that different blood vessels vary with respect to their mode of cardiovascular regulation, primarily through differential biochemical pathways and distinct receptor populations (i.e. NO modulatory pathways and differential $\alpha$ and $\beta$-adrenoceptors). (Abstract shortened by UMI.)
Synthesis and characterization of UV-crosslinkable peptide-based polymers for the use in glaucoma treatment

Glaucoma is the leading cause of irreversible blindness that is characterized by situations in which the intraocular pressure within an eye is too high for the normal functioning of the optic nerve head. An indentation of the optic disc significantly transfigures the lamina cribrosa region of the optic nerve head. This project develops materials for an unconventional method of prevention; that is, by strengthening the lamina cribrosa by injection of a biocompatible and biostable polymer. A peptide-based polymer to integrate with the extracellular matrix is synthesized. The pentapeptide, VPGVG, was synthesized using optimized solution techniques and characterized prior to polymerization. Polymers with three different molecular weights were obtained and they were derivitized with dimethacrylate endgroups. Model compounds were synthesized with dimethacrylate groups attached to either the carboxyl or amine functionality of a single amino acid. A partial endgroup modification was seen and exposure to UV light provided partial crosslinking.
A 3D Fractal Model of the Dog Kidney Cortex with Application to Multiple Indicator Dilution Tomography

A 3D computer model of transcapillary indicator exchange in the dog kidney was developed using a fractal tree and Goresky-Ziegler-Bach (GZB) exchange units to represent the arterial vessels and the post-glomerular capillary bed respectively. Vascular and transcapillary markers were tracked in thin slices through the cortex to simulate indicator events recorded on 2D tomographic images. I analyzed these images (thin slices) to (1) determine if the kinetics, found by best GZB parameter fits to the images, matched the actual kinetics in the 3D model, and (2) assess by fractal analysis the degree of self-similarity in the indicator distribution on the images. I found that the best-fit kinetics differed systematically from the actual kinetics. The fractal organization of indicator dynamics in thin slices was very sensitive to the 3D structure of this class of models, suggesting that key spatial parameters of renal cortical transcapillary exchange might be probed quantitatively 'in vivo'.
Heat transfer in bone during drilling

A numerical simulation was used to perform a parametric analysis of the thermal impact of bone drilling operations. The following parameters were varied: drill rotational speed, feed rate, helix angle, point angle, drill diameter, and the density, specific heat, and thermal conductivity of bone. The maximum temperature and resultant thermal damage increase with drill rotational speed. The temperature rises with feed rate from 0.45 to 1.8 mm/s, and decreases slightly up to the maximum feed rate of 4.5 mm/s. In the range of helix/point angle combinations examined, the minimum temperature rise occurs at 38° helix angle and 130° point angle. The maximum temperature increases with drill diameter. The temperature and thermal damage decrease with increasing thermal property values. An experimental investigation of the thermal conductivity of bovine cortical bone was also conducted. The conductivity was found to be 0.58 ± 0.018 W/mK in the longitudinal direction, 0.53 ± 0.030 W/mK in the circumferential direction, and 0.54 ± 0.020 W/mK in the radial direction. These results indicate that bone can be considered thermally isotropic for modelling purposes.
Italian Canadian women crossing the border to graduate education

This dissertation examines the educational experiences of women in graduate education whose parents are Italian immigrants. Data are collected through in-depth interviews with Italian Canadian women about schooling, family, ethnicity and relationships. The women's experiences are discussed in the interconnected contexts of the Italian immigrant experience, the education system, and, in particular, graduate education. Although Italian immigrants and their descendants form one of the largest ethnic groups in Canada, their participation in the educational system has gone largely undocumented except as part of large studies on various ethnic groups in the Metropolitan area. The second generation of Italian Canadians has been educated in the Canadian system and raised by immigrant parents who have had little experience with this system. Using qualitative methods, this study examines the educational experiences of Italian-Canadian women. The women are graduate students who were born and educated in Canada and whose parents immigrated to Canada in the post World War Two period. Being raised in an immigrant home has influenced the women's encounters with education and the decisions they have made. Issues of resistance and assimilation are considered in this study. Findings from this research include the discovery of four roles which the women adopt in order to "survive" graduate school. The women develop these roles in order to find ways to approach their graduate work while maintaining the important relationships in their personal lives.
Tetrafunctional cross-linking reagents, reaction with hemoglobin and the formation of hemoglobin bis-tetramers

Previously, a tetrafunctional reagent (DBIT) that reacts with hemoglobin to form hemoglobin bis-tetramers was developed. This thesis reports synthesis of other tetrafunctional cross-linkers with an isophthalic arrangement of either 3,5-dibromosalicylates or methyl phosphates. These cross-linking reagents were designed for the purpose of generating hemoglobin bis-tetramers. Results from cross-linking experiments indicate that the hydrophilicity of the cross-linker contributes to its ability to form the bis-tetrameric products. This thesis also reports the oxygen binding properties of hemoglobin bis-tetramer formed in the reaction of the hemoglobin with DBIT. The results indicate that the bis-tetramer has low oxygen affinity and almost no cooperativity in oxygen binding.
An investigation of attentional demand in a simulated driving environment

Driver's attention is a dynamic process which is dependent on the demands of the driving task, the environment, and the driver's internal state. The primary objective of this study was to examine how attentional demand changes as a function of vehicle speed, road curvature and lane width and to establish baseline quantitative measures of attentional demand for these variables. A corollary objective was to determine whether results obtained from a low fidelity driving simulator would correspond with results obtained from an on-the-road study. Attentional demand was measured in a driving simulator using visual occlusion. It was calculated as the percent of the driving time that the visual occlusion glasses were open. Results revealed that attentional demand increases as speed increases and as lane width decreases, and is greater for curved as compared to straight roads. In addition, behavioural validity was found between the low fidelity simulator and on-the-road experimental results.
Design and analysis of a high-frequency needle-based ultrasound imaging system

A needle-based imaging system has been developed for high frequency ultrasound applications. A 775 [mu]m by 540 [mu]m PZT imaging transducer is mounted in the bevel of a needle to create a probe, and the needle rotated about its axis to generate radial sweep images. Characterization of these probes, operating at a frequency of 41 MHz, has shown the ability of the system to routinely obtain axial and lateral resolution levels of 44 [mu]m and 95 [mu]m respectively. Other measured specifications include an 80% bandwidth, and 4-8 mm ultrasound penetration depth in 'ex vivo' kidney and liver tissues. ' In vitro' phantom work has demonstrated the system's ability to clearly quantify sub-millimeter cast vessels, with image quality and resolution far surpassing clinical intravascular ultrasound systems, which utilize similar transducers. Images of 'ex vivo' human liver and kidney tissue samples show good structural correlation with corresponding histology sections. Differentiation based on tissue type was performed using spectral slope and intercept parameters. Preliminary 'in vitro' pulsed wave Doppler studies have demonstrated the feasibility of detecting blood flows on the order of 1-2 mm/s using the needle probe.
Illness experience of Chinese immigrants with chronic fatigue and weakness

Chronic fatigue and weakness are common complaints afflicting patients seeking relief from physicians world-wide. People of Chinese decent comprise the largest visible minority and fastest growing language group in Canada (Statistics Canada, 1996). Traditional Chinese health beliefs and practices are vastly different from the biomedical model on which the Canadian health care system is based. 'Purpose'. To clarify the illness experience of Chinese immigrants suffering from chronic fatigue and weakness and to determine its practical clinical significance. 'Theoretical framework'. Kleinman's (1980) Explanatory Model of Illness, Goffman (1963) and Kleinman and colleagues' (1995) theories on stigma. 'Method'. Ethnographic study with a quantitative component. 50 Chinese patients referred by their family physicians were interviewed using the EMIC (Explanatory Model Interview Catalogue) a semistructured instrument, for studying illness experience (Weiss, 1997). 'Results'. The impact of migration is a dominant theme in most patients' narratives of their health problems. Patients reported multiple symptoms, predominantly somatic. Due to the "unknown nature" of their illness and the inability to live up to the Chinese ethos of hard work and family glory, participants felt stigmatized not just for themselves but for their families. Avoid disclosure was their preferred strategy for minimizing the pain of perceived stigma. Social and contextual issues, such as interpersonal conflict and underemployment were the most prominant perceived causes of their fatigue. Informants sought help from multiple sources for their illness, with the majority relying on self-help, family, and friends. Despite limited efficacy of treatment from Western physicians, participants were satisfied with doctors who were supportive and showed interest in their concerns. Practitioners of traditional Chinese medicine were regarded as healers who could "get to the root" of their illness, but financial constraints deterred help-seeking from this group of caregivers. 'Conclusion'. Findings of this study indicate the complexity of patients' explanatory models of illness. The practical significance of illness experience and its impact on stigma, help-seeking, course and outcome should be studied further in the context of the Canadian multicultural mosaic. Clinicians need to pay attention to adjustment issues confronting immigrant patients who suffer from an ill-defined chronic illness, as well as other disorders.