VictorJuiz/thesis huggingface dataset:
A computational method for analyzing interval-censored time-to-event data in the presence of informative examination times

In statistical analysis of time-to-event data, there are situations where the event of interest is only known to have occurred within an interval of time. Such data are considered interval-censored. In studying the human immunodeficiency (HIV) epidemic, interval-censored time-to-event data arise naturally, since the time an individual becomes HIV positive is not exactly known. In addition, individuals may undergo multiple tests before an event (HIV infection) is observed. When these tests are requested instead of pre-scheduled, their visit pattern may reflect individual risk behavior for which covariate information is not available. Therefore, the test visit times are said to be informative for the risk of HIV infection. Statistical methods that model the dependence between the event of interest and examination times are required for the analysis of such data. Farrington and Gay (1999, Statistics in Medicine 18: 1235-1248) analyzed interval-censored data with informative examination times using random effects which capture the correlation between individual's risk and visit rate. However, their proposed methodology is based on an approximation of the marginal log-likelihood and relies on large number of visits per individual. We developed a method for analyzing interval-censored time-to-event data with informative examination times, which addresses the limitations of the Farrington and Gay's method. Our method avoids the likelihood function approximation embedded in their method, thus leading to less biased parameter estimates and more accurate standard errors. Expectation-Maximization (EM) algorithm is used for parameter estimation. We employed multiple imputation of event times via Sampling/Importance Resampling method (Rubin, 1987, JASA 82). This reduced the likelihood of interval-censored time-to-event data to that of right-censored data. We evaluated the bias of parameter estimates of the proposed method and the accuracy of their standard by simulations. Under most simulation scenarios the new approach resulted in reduced bias compared to the Farrington and Gay's method. We applied the proposed method to the analysis of the Polaris HIV repeat testers data in Ontario.
High precision optical interferometry and application to Be stars

A new technique for calibrating optical long-baseline interferometric observations is developed where both the calibration corrections and the source characteristics are obtained from the observations of a program star. This calibration technique can only be applied to certain classes of objects, such as emission line sources or binary systems, where the parameters describing the characteristics of the source have different functional dependence than the calibration parameters. To demonstrate its effectiveness, the technique is applied to observations of four different Be stars obtained with the Navy Prototype Optical Interferometer. The interferometric observations utilize measurements obtained simultaneously in many spectral channels covering a wide spectral range, where only two channels contain a strong signal due to the circumstellar envelope in the Halpha emission line. The calibrated observations in Halpha allow modeling of the circumstellar envelopes of all four stars with circularly symmetric and elliptical Gaussian models. The best-fit model parameters are then combined with similar results for other Be stars, already published in the literature, to study the relationship between the Ha emission and the physical extent of the Halpha-emitting circumstellar region. For the first time, a clear dependence of the net Halpha emission on the extent of the circumstellar region is demonstrated. These results are consistent with an optically thick line emission that is directly proportional to the effective area of the emitting disk. Within the small sample of stars considered in this analysis, no clear dependence on the spectral type or stellar rotation is established, although the results do suggest that hotter stars might have more extended circumstellar regions.
Investigating the factors that attract and dissuade Canadian medical students from a career in internal medicine

Further studies should explore and confirm these findings and should focus on determining the aspects of internal medicine that deter students. This study suggests that medical school experiences and the reputation of internal medicine as an intellectually challenging field that fosters patient-doctor relationships are critical for attracting medical students. Ensuring an adequate number of future internists requires understanding the factors that influence career decisions. 154 senior Canadian medical students responded to a survey. Students choosing internal medicine did not differ from those rejecting it in terms of key demographics. The most important factors for those choosing internal medicine were: intellectual stimulation, experiences with role models, staff, and residents, and emphasis on patient care as an internist. In regression analyses, the most important predictors for choosing internal medicine were: nature of the practice, geographic location of training program, past experiences in the area, and the challenge of academic work.
The role of dopamine D(2) occupancy in the vacuous chewing movement (VCM) model of tardive dyskinesia

Background. Dopamine D2 receptor occupancy has proven to be an important factor in understanding how antipsychotic medications exert their beneficial, as well as adverse, effects. However, little is known about the relationship between D2 occupancy and risk of tardive dyskinesia, a potentially irreversible motor side effect. Objectives . Using the vacuous chewing movement (VCM) animal model for tardive dyskinesia, we sought to determine (a) whether there is a relationship between antipsychotic dose and induction of VCMs; (b) the role of D 2 occupancy in the development of VCMs; (c) the differential effect of continuous (minipump) versus transient (subcutaneous) D2 occupancy on VCMs using haloperidol, a 'typical' antipsychotic; and, (d) whether continuous infusion of 'atypical' antipsychotics, in this case olanzapine and remoxipride, produces VCMs in a fashion similar to what occurs with the typical antipsychotic, haloperidol. Methods . A series of animal studies were carried out to address each of these objectives, with a similar treatment model forming the basis for each comparison. Other than haloperidol, where haloperidol decanoate was used, the model compared daily subcutaneous injections (transient D2 exposure) with minipump infusions (continuous D2 exposure). VCMs were measured over a 2-minute test period weekly for a period of 2 months. D2 occupancy levels were measured ex vivo using [3H]-raclopride. Results. (a) There is a relationship between antipsychotic dose and VCMs; (b) the likelihood of developing VCMs is dependent upon the level of antipsychotic-induced dopamine D2 receptor occupancy; (c) antipsychotic-induced continuous D2 receptor occupancy via minipump is significantly more likely to lead to the VCM syndrome than transient D2 receptor occupancy via daily subcutaneous injections; and, (d) atypical antipsychotics such as olanzapine and remoxipride also lead to the VCM syndrome when administered via minipump. Conclusion . Collectively, these studies have underscored the important role of both continuous drug infusion and continuous dopamine D2 occupancy in the development of the VCM syndrome in rodents, which in turn has clinical implications related to the induction of tardive dyskinesia in humans.
An examination of psycho-social conditions under which provincially sentenced women offend

Findings from this study support previous research that emphasizes the need for a gender responsive framework in understanding women's offending as well as the importance of examining 'dynamic' factors in women's offending. Results point to the role of victimization, substance abuse, poverty, marginalization and its long-term impact on mental health and women's capacity for survival. Implications for women's abilities to overcome these barriers in their successful re-integration into the community are discussed as well as the need for addressing these issues in designing correctional programs and policy. This study investigated psychological and social conditions under which provincially sentenced women offend. It examined women's present day life circumstances (i.e. economic disadvantage, current addictions, adult victimization, employment, and unstable housing and social support), psychological functioning (i.e. coping styles, self-efficacy, attributional style, mental distress), attitude to crime, historical factors (criminal history, childhood victimization) and their influence on women's offending. Findings demonstrated that women offenders were doing significantly worse on various aspects of psychological functioning and mental health compared to women in the general population and recidivists were experiencing significantly greater problems in areas of social support, adult victimization, addictions and poverty than first time offenders. Overall, women offenders did not appear to demonstrate procriminal attitudes, however, significantly more recidivists had histories of juvenile offending, problem avoidance styles as well as slightly more procriminal attitudes than first time offenders. 'Higher rate' offenders demonstrated significantly more problems with current addictions, unemployment, poverty and histories of juvenile offending. Psychological functioning, difficult life circumstances and experiences of historical disadvantage were factors that explained higher rates of offending in the group of 'higher rate' offenders. Experiences of historical disadvantage and difficult life circumstances explained diverse aspects of psychological functioning including low self-efficacy, use of problem avoidance as a coping style, mental distress and pessimistic attributional style. Results also demonstrated that for recidivists poverty was a salient factor in re-offending.

Keywords: Females offenders, Social conditions
Females offenders, Ontario
Recidivism, Ontario
Females offenders, Rehabilitation
Females offenders, Ontario
Females offenders, Psychology
Females offenders, Ontario
Capacity to consent to treatment in adolescents with anorexia nervosa

Overall, healthy adolescents demonstrated decision-making skills that were superior to adolescents with anorexia nervosa, regardless of the context of the decision (e.g., medical versus psychiatric). Furthermore, adolescents with anorexia nervosa were significantly less able to reason about treatment for their own illness than they were for hypothetical illnesses. These findings are discussed in terms of their clinical implications. Over the last three decades, the rights of children and adolescents to exercise autonomy in the consent process have expanded. In Ontario, the Health Care Consent Act stipulates that everyone, regardless of age or diagnosis, should be considered capable to make his or her own treatment decisions. Clinical encounters with patients with anorexia nervosa have brought forth challenging ethical and legal issues surrounding the capacity of these patients to make their own treatment decisions, owing largely to the cognitive distortions that are part of the diagnostic criteria for the disorder, as well as serious and potentially life-threatening complications of treatment refusal. The current study compared the ability of adolescents with and without anorexia nervosa to make treatment decisions about hypothetical illnesses, presented in the form of vignettes. Adolescents with anorexia nervosa were also assessed with regards to their decision-making skills for their own illness. In addition, the relationship between cognitive and maturity of judgment variables and the ability to make a treatment decision was examined. The results suggest that adolescents who are hospitalized for anorexia nervosa appear to be less mature than healthy adolescents with regards to responsibility, a component of maturity of judgment. The adolescents with anorexia nervosa were no different from healthy adolescents on the remaining cognitive or maturity of judgment variables.

Keywords: Teenage girls, Psychology
Informed consent (Medical law)
Teenage girls, Diseases
Anorexia nervosa, Psychological aspects
Incorporating motivation into predictive models of academic performance: Development and validation of the motivation for academic achievement scale

This paper describes the development and validation of a questionnaire measuring Motivation for Academic Achievement. The questionnaire was designed to clarify the construct of academic achievement motivation, and to assess the extent to which this construct is able to predict academic achievement once dispositional variables (i.e. intelligence, personality, and demographics) have been controlled for. A 20-item pilot scale measuring general motivation was developed through interviews with successful graduate and senior undergraduate students, and a 100-item scale measuring attributional style was developed through a literature review; these scales were then completed by 192 undergraduate participants. Exploratory factor analysis revealed 5 and 12 factors, respectively, in the two scales; yet, only 3 of these factors (self-discipline, intrinsic motivation to achieve, and ability attributions for failure) independently predicted GPA. These 3 variables alone, however, predicted over 30% of the variance, and adding IQ to the regression model increased the explainable variance to 54%.
Knowledge discovery in databases of web use: data mining for informetric and behavioral models of information seeking on the World Wide Web

The present study investigates the World-Wide Web use of knowledge workers in an organizational environment. The goal was to gain a baseline understanding of corporate Web use and to develop informetric and behavioral models of browsing and searching the Web. Data describing Web access was primarily collected through custom-configured internet firewall software at a large corporation comprising over 1500 individual Web users for a period of 35 days. Three models from Informetric research were applied to analyze the Web use of study participants. The Web use data collected shows that individual Web users can be categorized by their frequency of use similar to a Lotka's law-like pattern of activity. Discernible clusters of predominantly used Web sites relevant to the entire study organization of Web users were also found, similar to Bradford's Law of Scattering which is traditionally used to identify clusters of influential journals in a scientific domain. Moreover, a related distribution was found in the aggregate popularity of unique Web pages accessed that show a Zipf-like distribution of overall Web use at the study organization. A general behavioral model of Web use incorporating modes of information seeking and Web browser moves was also tested by analyzing the Web use activities of the study participants. Follow up interviews and on-site observation provided additional context. Results suggest a multi-modal use of the Web with significant effort devoted to both undirected and conditioned viewing of Web resources that involved behavior such as chaining and browsing moves, seen as following links to explore information on a particular Web site. Additionally, prevalent searching modes were noted that included heavy monitoring and extracting of Web-based information, such as frequent visits to Web pages of interest and comprehensive searches using Web search engines. This behavioral model serves primarily to provide a framework for identifying and understanding the activities that influence Web use. It may also serve as a model for future comparison of Web use studies, as well as provide insights for designing both Web information resources and applications to access them. This work represents an exploratory investigation into the Web use behaviors of an organization of knowledge workers. The amount of data collected in the study and subsequently analyzed using Knowledge Discovery in Databases techniques has also yielded new ideas about analyzing Web usage data. The results of this dissertation suggest that there are both informetric and behavioral models that can be combined to describe Web use in an organization with the potential for enhancing Web access technologies, knowledge work and overall Web interaction for all Web users.

Keywords: Internet users
Data mining
World Wide Web, Use studies
Hustling to host: everyday practice, pedagogy and participation in British Virgin Islands tourism

By reconceptualizing tourism in the British Virgin Islands as a site of political and pedagogical struggle, this qualitative inquiry explores the complex and contradictory structures and practices embodied in tourism formation. In approaching tourism from a host perspective, I intervene in the dominant economic benefits and paradise promotion discourses, to focus on critical questions about the entanglements of power, knowledge, desire, representation, and identification. It has become normal for local enactment of tourism to be framed from the guest perspective, often to the exclusion or avoidance of a focused reading of what it takes, or what it means to construct the leisure product represented globally as “Nature's Little Secrets.” I argue that the hegemonic discourse and pedagogy of tourism production has not adequately considered the usefulness of historical contingencies, multiple subjectivities, and ordinary agency in its appeal for participation. For an alternative rendering, I include the perspectives of twelve participants who operate within and on the edge of the vibrant and turbulent terrain of tourism. Their stories, like their practices refute any simple or singular notion of them as happy natives, cultural dupes, or unknowing subjects. By drawing on the performative and protean tactics essential to their negotiation of possibility beyond mere survival, I appropriate the vernacular concept of hustling. This figuration enables me to theorize how local participants in the small, informal, marginalized, or little explored sectors of the industry strive to make meaning of their sense of place, belonging, and value in the whole tourism dynamic. In opening new dialogical space for advancing the interdisciplinary study of cultural formation in diverse learning sites and among different engaged groups and individuals, this thesis aims towards connecting and expanding the discursive fields of performative agency and public pedagogy for effecting more inclusive and meaningful participation.

Keywords: Tourism, British Virgin Islands
Tourism, Social aspects
Tourism, British Virgin Islands
Social change, British Virgin Islands
La ville comme object de la justice =The city as the subject of justice

The aim of this dissertation is to develop and defend an account of the contemporary democratic city from the perspective of justice. Liberal philosophers have been engaged in heated debates over the nature of the just society and the set of principles that should be used to evaluate it. One main source of disagreement concerns the scope of these principles. Some are committed to the possibility of universal principles of justice that would apply to any social institution or interaction. Others believe that principles of justice should vary as a function of institutional context. For instance, it is assumed that many principles only apply within the context of the nation-state. This dissertation takes the city, rather than the state, as the subject of justice. The aim is to show that the demands of justice at the level of the city are not captured by theories of justice developed for the state (or for the basic structure of society). The dissertation is divided into three parts, each of which presents one of the central institutional features of the city that is important from the perspective of justice. The aim is to show how three assumptions of contemporary theories of justice (the absence of exit options, the neutralization of externalities, and the expectation of reciprocity) must each be modified in order to accommodate the specific institutional characteristics of the city.
Gentlemen bankers, politicians and bureaucrats: the history of Canadian Bankers Association, 1891-1924

This is a history of the Canadian Bankers Association, a Canadian trade association unlike any other. Its origins are linked to deficiencies in Canada's Bank Act, 1871 and policies distancing the federal government from demands for assistance from weak banks and their victims—depositors, note holders and investors. Bank failures in the 1870s and 1880s added weight to calls for safer banks and more government regulation, pressure many bankers feared would cause reforms undermining the flexibility the Bank Act allowed them to exercise in their day to day business. A small number of prominent bankers avoided this danger by proposing a fund all banks would to contribute for the protection of note holders. They also suggested a bankers' association to guard the interests of the fund's contributors and ultimately the public. When bankers launched their organization, it had specific, yet unwritten, obligations to the federal government. It was supposed to make banking safer and, under pressure from the finance department, limit competition for deposits, a business the government was involved in through its Post Office and Dominion Savings Banks. This thesis will trace the role of the CBA between 1891 and 1924 and show it was anything but a “cozy cartel,” as some scholars have alleged. Competition and rivalry divided Canadian bankers and produced a feckless trade association that could do little to meet calls from governments and those that elected them for safer banks. For Canadian bankers and their association, failure soured relations with politicians and sowed the seeds of public cynicism, leaving a legacy that has shaped the way Canadian governments make bank policy.

Keywords: Banks and banking, History
Banks and banking, Canada
Aircraft wing anti-icing system: modelling, integration, and validation

Aircraft wings are vulnerable to ice accretion during flight due to high exposure to on-coming air. This may cause disruption to the aerodynamics of the aircraft's lifting surfaces and pose a threat to aircraft safety. For most civil aircraft, a thermal anti-icing system is introduced to transmit engine hot bleed air into the leading-edge's surface to maintain surface temperature above the icing condition. The overall system involves thermal, pneumatic and control disciplines and their interactions make it a challenging task in systems design and analysis. Recently the University of Toronto Institute for Aerospace Studies (UTIAS) has initiated research in developing an integrated aircraft wing thermal anti-icing control and simulation system for engineering analysis of temperature distribution prediction, control design, tuning and sensitivity studies. This thesis, as part of the above research initiative, presents the pneumatic development, system integration, and validation with a demonstration using an example aircraft wing anti-icing system.

Keywords: Aerodynamics, Mathematical models
Airplanes, Ice prevention
Airplanes, Wings
Heat, Transmission