VictorJuiz/thesis huggingface dataset:
Development and validation of an osteoporosis risk assessment instrument (ORAI) to select women for bone densitometry

Dual energy X-ray absorptiometry (DXA) is the standard for osteoporosis diagnosis. While mass screening for osteoporosis has not been recommended, there is no consensus regarding targeted screening. Baseline data from the Canadian Multicentre Osteoporosis Study were used to develop and validate an Osteoporosis Risk Assessment Instrument (ORAI) to select women for bone densitometry. ORAI uses a case-selective approach to screen for osteoporosis by summing a score based on current: age, weight and estrogen use, to identify women likely to have low bone mineral density who may be recommended for DXA testing. Appropriate therapy can then be offered to those at risk of debilitating osteoporotic fractures. The 3-item ORAI resulted in selection of over 90% of those with osteoporosis, and less than 43% of those with normal bone mineral density for DXA testing. This could mean 39% less DXA testing compared to a mass screening approach.
Pharmacological treatment of first episode non affective psychosis, are typical doses of haloperidol for Caucasians appropriate for Asians?

This study investigates possible Asian-Caucasian differences with respect to the metabolism and central nervous system (CNS) effect of haloperidol in the treatment of first episode non-affective psychosis. The two part study involved a 4-week active treatment phase and a 9-month follow-up. An attempt was made to control for other identified differences such as initial impairment, tolerance of symptoms, compliance and medication side effects. Fifteen Asians and sixteen Caucasians participated in the four-week trial of treatment phase. Subjects were maintained on low oral doses of haloperidol (2mg./day) for the first week of treatment. Doses were increased weekly to 5mg., 10 mg. and finally 20 mg./day until the 'optimal therapeutic dose' was achieved. This was defined as the point at which subjects: (a) experienced significant clinical improvement; or, (b) developed extrapyramidal side effects. On average, the same dose--5 mg./day--was optimal for both Asian and Caucasian subjects. At a fixed dose of 2 mg haloperidol, Caucasian males had significantly lower plasma haloperidol levels than Asian males. No differences in plasma haloperidol levels were found between Asian and Caucasian females. There was no ethnicity effect or gender effect on plasma prolactin levels (change from baseline) after one week of treatment, implying that there were no differential prolactin response secondary to neuroleptic use. At the end of 4 weeks, Asian subjects were responding less well to treatment than Caucasians. Covariance analysis demonstrated that this difference in initial improvement could be attributed to longer duration of illness onset, and greater proclivity to side-effects secondary to neuroleptic treatment among Asian subjects. At 9-month open drug follow-up, Asian patients had unproved to the point where their therapeutic gains matched those of the Caucasian subjects. In conclusion, the study demonstrated Asian and Caucasian differences with respect to the metabolism of haloperidol in the treatment of first episode non-affective psychosis. There were no statistically significant ethnic differences in central nervous system (CNS) effect of haloperidol.
Scalable subband/wavelet coding and space-frequency block matching for digital video

Efficient representation of digital video signals is key to many products and applications that will soon be extensively deployed. The scope of this thesis is the core technology for conventional compression of video: motion estimation, temporal compensation and prediction, spatial transformation, quantization, and entropy coding. Still-image compression techniques are a subset of the tools required for video compression. Although current still-image compression standards employ block-transform coding, subband and wavelet methods are now recognized as superior. A new family of biorthogonal 'nearly'-coiflet filters is introduced that possess near-maximal vanishing moments and smoothness (regularity). The design procedure for this family enables time-frequency footprints with for good image-compression performance. Medium-length filters enable superior reproduction of the high-frequency details that are key for video interframe coding. Although often examined independently, quantization, bit allocation and entropy coding may be improved through joint consideration. The performance bounds of Stack-Run coding, a computationally advantageous algorithm for quantization and entropy coding, are examined through the introduction of improved quantizers and the exploitation of two-dimensional spatial redundancy. New space-frequency quantization algorithms enable the relative advantage of joint quantization and entropy coding to be explored. The primary source of redundancy in video is temporal. Compression, the removal of redundancy, is accomplished through the techniques of motion estimation and compensation. This thesis offers two contributions to the temporal processing of video. Although wavelet coding is preferred for lossy image compression, the lack of a block-based intra-block/inter-block switching mechanism prevents efficient coding of video interframes. Space-Frequency block matching is suggested to compensate. Space-Frequency block matching provides a new capability for frequency-adaptive motion-compensated prediction that proves advantageous not only for wavelet interframes, but also for conventional block-transform coding of interframes. Despite success with spatial coding, transform and subband coding are poorly suited to application in the temporal domain. Spatial adaptation that permits both temporal-subband coding and motion-compensated prediction (TSB-MCP) within a single frame spans the gap between the two methods. The hybrid permits coding gain to be sacrificed to increase temporal scalability. A fundamental advantage of the new structure over 'closed-loop' MCP is the simplicity of optimal bit allocation in the 'open-loop'.
Design of a cure monitoring system for composite aircraft repair patches

Aircraft repair patches make use of thermosetting polymers and the quality of the repair depends on proper curing. The design of a cure monitoring system for aircraft repair patches is explored. Cure monitoring was achieved by measuring the signal strength and time of flight of an ultrasonic wave transmitted through the material. Custom transducers, electronics and software was designed for the system. Preliminary results were encouraging. The present system does not provide accurate measurements of time of flight and thus can not provide a quantitative assessment of the material properties. However, qualitative results based on changes in signal strength provided important information regarding the state of cure of the thermoset. Several cure tests accompanied by mechanical tests demonstrated the usefulness of the present system. Recommendations for creating a commercially viable system are given. The system was used to evaluate the practicality of Bragg grating fibre optic sensors as cure monitoring devices. Bragg gratings do not appear to produce useful cure related data.
Molecular events during melanoma transendothelial migration in vitro

Extravasation of tumour cells is integral to metastasis. However little information is available which describes the transendothelial migration of tumour cells. To examine the extravasation process of tumour cells, we developed an 'in vitro' model of transendothelial migration which involves the co-culture of human melanoma cells on a monolayer of human endothelial cells cultured on Matrigel. Actin dynamics during the process were studied using laser scanning confocal microscopy. The results revealed that dramatic changes in the organization of the actin cytoskeleton take place, along with dynamic changes in the cell shape of both melanoma and endothelial cells, during melanoma transendothelial migration. Furthermore, the cytokine TNFÃ was found to increase the ability of poorly metastatic cells to undergo extravasation, suggesting that adhesion and diapedesis are distinct steps in the process. In contrast to the transendothelial migration of leukocytes, which involves PECAM-1/CD31, CD31 was redistributed away from endothelial cell-cell contacts juxtaposed to the melanoma cells and the protein was absent from heterotypic contacts between the two cell types, suggesting that the attachment of melanoma cells can signal the dissolution of endothelial CD31-mediated adhesion complexes. These results indicate, for the first time, that tumour cell extravasation is different from that of leukocytes. We also determined that the distribution of VE-cadherin during melanoma extravasation. was similar to that observed for CD31. In contrast, we have evidence that classical cadherins are present in heterotypic contacts between melanoma cells and endothelial cells during the process, and suggest that N-cadherin might be one of these cadherins. Finally, we investigated the role played by the Ãvß 3 integrin, since levels of this integrin are known to increase with the progression of disease. We observed Ãvß3 integrin in melanoma membrane blebs and in heterotypic contacts between melanoma cells and endothelial cells. The transmigration of melanoma cells was inhibited both by antibodies directed against Ãvß3 and by a cyclic RGD peptide, suggesting that Ãvß 3 is involved in the migration of melanoma cells through the endothelial junction. Our results also suggest that melanoma Ãvß 3 interacts with the cell adhesion molecule L1 on the endothelial surface. These results not only define the sequence of events involved, but also bring new insights into the mechanism of tumour cell extravasation. Our ' in vitro' model system should provide a useful paradigm for further investigation of the molecular and cellular events which take place during tumour cell transendothelial migration.
Bridging the gap, exploring the information needs and information use of front line child protection intake workers

This is a study of how front-line child protection intake social workers (front-line workers) at selected Children's Aid Societies in Ontario perceive their information needs, and how they use information and information systems in relation to these needs. This study employs a qualitative ethnographic approach to examine the of 25 front-line workers in the context of the following questions: (i) How do front-line workers perceive their information needs in the context of their assessment-related tasks? (ii) What are the gaps, barriers and helps that front-line workers encounter in attempting to meet these needs? (iii) What information-seeking behaviour of front-line workers with respect to information sources and systems? Applying the "sense-making model", which emphasizes as critical the perspective of the information-user and provides a useful analytical framework in its vocabulary of "gaps", "barriers" and "helps", this study finds that front-line workers perceive a profound disjunction between their Information needs and the formalized information systems at their disposal. In order to effectively perform their central gate-keeping functions of initial client assessment in the time and resource constrained realities of present-day child protection work, front-line workers require case-relevant Information in a timely highly accessible and "user-friendly" format. The information base of the agencies investigated, however, appear to fail far short of this ideal, serving as they do several masters in the competing and sometimes conflicting information requirements of a variety of legal and administrative stakeholders within and outside of the agency. The result of this "top-down" design is a monolithic and bureaucratic information system that front-line workers consider for their purposes as remote unwieldy and largely unresponsive to their assessment-related needs. Observation of front-line workers in the performance of their tasks reveals that an alternative and informal information system appears to have evolved organically and spontaneously alongside the formal. This loosely-structured, system appears to represent a grassroots, "bottom-up" response to the perceived shortcomings, of the formal one. Its main method of information transmission is oral rather than written, and the narrative vehicle is of critical import as a mode of information transfer. significantly, rather than hub and centerpiece of the information system, the computerized Information base is, to a large degree, marginalized. Unless the gap is bridged between what the front-line worker perceives as his or her information needs in the context of assessment and what is formally provided by the agency, an ever increasing reliance on computerized information systems threatens to perpetuate, or exacerbate, this gap.
The relationship of anger, self-silencing and feminist consciousness to disordered eating symptomatology in women

To date, most research studies have examined the relationship between the emotional experience of depression and eating disorders. As with dysphoric affect, anger has been linked to disordered eating symptoms, however, the consideration of the role of anger in women's coping strategies has been generally neglected and under-researched in the clinical literature. The purpose of the current investigation was to study the relationship of anger, self-silencing and feminist consciousness to eating disturbance. It was predicted that women with greater disordered eating symptomatology would experience higher levels of trait anger, anger suppression and self-silencing, and display a lowered awareness of feminist consciousness. Two hundred and five female university students completed a demographic and behavioral questionnaire, the Eating Attitude Test (EAT-26; Garner, Olmsted, Bohr and Garfinkel, 1982), the Eating Disorder Inventory (EDI-2; Garner, 1991), the State-Trait Anger Expression Inventory (STAXI, Spielberger, 1996), the Feminist Identity Development Scale (FIDS; Bargad and Hyde, 1991), and the Silencing the Self Scale (STSS; Jack, 1991; Jack and Dill, 1992). The design of the study was correlational. The main finding confirmed an association between disturbed eating and anger. Overall, the group of respondents endorsing greater symptoms of disturbed eating, showed significantly higher levels of both trait anger and inwardly directed anger. No similar associations were found between disturbed eating symptomatology and the outward expression of anger or anger control. The hypothesis predicting a significant inverse correlation between anger suppression and feminist consciousness was not supported. Similarly, no support was found for an association between feminist consciousness and the tendency to express anger outward. Self-silencing was significantly and positively correlated to disturbed eating symptomatology. Additionally, as self-silencing increased, so did the tendency to suppress anger. Finally, anger suppression and self-silencing were significant predictors of disturbed eating. These results and their implications are discussed and understood within the larger sociopolitical context that affects women's lives. One of the implications to clinical practice is that therapists need to be aware, not only of the relationship of suppressed anger to disturbed eating in their female clients, but also of their own internalization of socially sanctioned gender roles that may inadvertently silence assertive expression by their clients. One of the implications of the findings to prevention is that adolescent females may be helped to divert their anger by having the opportunity to voice their opinions and by actively engaging in transforming their environment in a way that makes them feel safe, respected and empowered.
Phase segregation in multi-component polymer systems

The phase segregation investigated in this work is the migration of dispersed particles or droplets to preferred locations in a polymer melt. An understanding of this area can lead to polymer processing directed at de-mixing polymer blends for recycling purposes and at the formation of multi-layer structures of polymers without co-extrusion. Although it is now recognized that viscosity ratio is an important factor in achieving phase segregation in polymer melts, non-Newtonian and elastic effects complicate the situation. This thesis is an investigation of these effects. The thesis centers on testing four hypotheses: (1) phase segregation does not take place in a Newtonian fluid; (2) in a shear thinning fluid having negligible elasticity, migration of the dispersed phase will be towards the high shear rate region of the flow; (3) in a significantly elastic fluid having negligible variation of viscosity with shear rate, migration of the dispersed phase will be towards the low shear rate region of the flow and; (4) in a fluid which is both shear thinning and elastic, the direction and extent of migration will depend upon the relative "strength" of the shear thinning and elastic effects. The validity of these hypotheses was tested using three types of experiments (all conducted at 250°C): melting and shearing a rod of the polymer containing the particles at well defined positions in a Couette apparatus (Couette-Rod Experiments); shearing of a polymer melt containing dispersed phase, which was extruded into the Couette apparatus (Couette-Extrusion Experiments) and; flow of a polymer melt containing the dispersed particles in a very long tube (Tube Experiments). Experiments were performed using both rigid particles (Glass beads) and deformable droplets (Polyamide 612 (PA612) droplets) as the dispersed phase. Polycarbonate (PC) was used as the Newtonian fluid for testing the first hypothesis. Poly(acrylonitrile butadiene styrene) copolymer (ABS) melt served as the test fluid in validating the remaining three hypotheses due to its particular dependence of rheological characteristics upon the shear rate. (Abstract shortened by UMI.)
Insulin receptor-related receptor messenger ribonucleic acid levels are up-regulated in enterochromaffin-like cell pathophysiology

The insulin receptor-related receptor (IRR), an orphan member of the insulin receptor family, is selectively localized in the stomach to a subset of neuroendocrine cells, the enterochromaffin-like (ECL) cells. ECL cells are the pivotal regulators of gastric acid secretion. The physiological role of IRR was investigated by analyzing its mRNA levels using semi-quantitative RT-PCR in two states of ECL cell pathophysiology in the rat. First, hypergastrinemia which stimulates ECL cell activity and replication was induced by gastric gavage of omeprazole which blocks acid release. Second, a hypogastrinemic state in which ECL cell activity was reduced was achieved by fasting. As expected, mRNA levels of the ECL cell markers histidine decarboxylase and gastrin receptor increased in hypergastrinemia and decreased with fasting. IRR mRNA levels also were shown to parallel the increase in ECL cell activity in hypergastrinemia. In fasting, however, like the insulin and IGF-I receptors, IRR mRNA levels increased despite the decrease in ECL cell activity. Since IRR mRNA levels were not exclusively conditional on ECL cell activity, they may represent a response to the decreased acid secretion or responses more specific to hypergastrinemia and fasting, for example to increased ECL cell activity and loss of ligand, respectively.
Concurrently browsing heterogeneous media with distributed media appliances, toward usability for the converging media environment

Each medium carries with it a characteristic paradigm for user interaction, imposes particular demands on the consumer/user and elicits certain responses. In the converging world of the Web, television (TV) and other networked media, the consumer/user is confronted with new modes of user-media interaction. Optimizing usability for such combinations of media, potentially used with distributed media appliances (presentation and control devices), requires a fundamental reconsideration of the user's relationship with this media environment. A conceptual model of the user-task-media-setting relationship was proposed encompassing media environment-specific responses (MESR), a media-setting compatibility principle and a task-setting compatibility principle. This framework was investigated in the context of two media: TV, as representative of a time-based medium, and the Web as representative of a document-oriented medium. Our study focused on browsing, a central activity in Web and TV use. Hypotheses were developed and tested with two experiments. The first experiment employed Web- and TV-specific browsing tasks with a single media appliance at a time, while the second utilized both the Web and TV in concurrent browsing tasks with two media appliances. User performance effects and subjective evaluations were studied. Experiment 1 manipulated 'medium, setting ' and 'task type' and used field dependence-independence as the subject factor. Effects with an alternate subject factor, ' Web'- or 'TV affinity', were also explored. Similarly, Experiment 2 manipulated 'setting' and 'task type' and utilized 'spatial integration ability' and 'media affinity' as alternate subject factors. Empirical results were derived showing evidence for the influence of: media-setting compatibility on subjects' MESR in both single- and dual-media/appliance environments; task-setting compatibility on subjects' MESR in dual-media/appliance environments; and, both field dependence-independence as well as Web- and TV-specific affinity on subjects' MESR. Additionally, the cognitive dimension of MESR was found to be the most prominent for both single- and dual-media/appearance environments. The major research contributions included the conceptual model, compatibility constructs, methodology and research instruments. A trio of usability design principles and several avenues for further research are suggested. The conceptual framework and methodology developed, as well as this initial set of empirical results, should provide a firm foundation and encouragement toward future research on user-media interaction within heterogeneous, concurrent-use media environments incorporating multiple media appliances.