The degree to which something stands out against the background of its environment communicates important information. The phenomenon of camouflage is a testament of the degree to which visual salience and probability of survival tend to overlap. Salient stimuli often elicit fast, reflexive movements in order to catch prey or avoid a predator. The overarching goal of the work presented in this thesis is to investigate how the physical salience of visual stimuli influence the programming and execution of reaching movements. I approached this question by recording kinematics and muscle responses during reaching movements. Broadly, this thesis investigates the effect of the physical salience of targets on the magnitude and latency of involuntary, spatially tuned muscle responses toward those targets. In Chapters 2 and 3, subjects reached toward an array of potential targets on a touchscreen. The final target was cued only after the reaching movement was initiated. From trial to trial, targets differed in their numerosity (i.e., how many on the left versus the right) and in their salience (i.e., their relative contrast with the background). Different amounts of delay were introduced between the appearance of the targets and the cue to move. The results from these two studies demonstrate that the physical salience of (i.e., the luminance contrast differences between) targets influences the timing and the magnitude of involuntary deviations toward the most salient target(s) during reaching movements. At the level of individual subjects, the degree to which someone involuntarily reached toward the salient stimulus was predicted by the relationship between processing speeds for the different target contrasts. In Chapter 4, subjects reached toward individual targets that varied in luminance contrast. Muscle activity in the right pectoralis major was recorded with intramuscular electrodes. Consistent with past studies, there was a consistent muscle response that was time-lock
Rapidly changing climatic conditions across the globe are believed to have an impact on key climate variables and the hydrologic cycle. Changes in magnitude and frequency of peak flow patterns have been noted in rivers worldwide. The associated risk is projected to increase many folds during the 21st century. Therefore, it is necessary to quantify these impacts for effective water resource planning and management in future. Methodology chosen to do so should be able to capture variations in climate variables at fine temporal, spatial and distributional scales. Also, it should be able to cover uncertainties associated with future climatic, socio-economic and physiographic projections. In this study, a methodology for making future flow projections has been presented and applied to the Grand River basin, Ontario, Canada. Results indicate consistent decreases in peak flows across the catchment for all the scenarios considered in the analysis.
This dissertation considers fundamental questions about real options reasoning and its application in the face of uncertainty: do firms behave as real options reasoning predicts, and are there performance benefits from its application? The concept of uncertainty is further developed by considering two primary types: technological uncertainty and market needs uncertainty. A qualitative industry level historical case study is performed on the flat panel TV industry, chosen because it exhibits high technological uncertainty and low market needs uncertainty. Real options logic predicts, in such an industry, that firms will develop and maintain technology options until uncertainty is resolved. Firm level case studies for major incumbent Japanese TV set manufacturers and other relevant firms are performed. Comparison across the cases, and between several specific firms is conducted to test and further develop theory. The firms studied are found to generally behave as predicted by real options logic. Evidence from the study does not present a clear relation between options-related behavior and performance. Although this study identifies evidence not holding options can have large negative performance results, firms holding options as predicted by theory did not realize lasting performance improvements. With one exception, firms attempting to leverage technological capabilities into improved market positions were unable to realize durable improvements in their positions. The development and release of flat panel TV coincided with changes in performance for many firms in the industry; however, these performance changes were short lived. By the end of the study period, industry players had generally returned to the trajectories they were previously on. Between-case analysis of several outlying firms in the sample provides a rich and nuanced view of requirements for firms to dramatically improve performance in the face of high technological uncertainty in a market with very la
The oral transmission and transformation of client information in an apprenticeship setting provides a rich environment in which to observe students and their expert supervisors managing uncertainty. In this Canadian-based study, we examined the communicative features of 12 social work supervisions involving social work students and their supervisors and enriched our observations with subsequent interviews of the participants. Findings: Social work students viewed the acknowledgement and examination of uncertainty as a touchstone of competent social work. This observation contrasted with our past study of medical and optometry students who focused on personal deficit and a distrust of acknowledging uncertainty. Our observations and interviews revealed a unique professional signature to the novice rhetoric of uncertainty (seeking guidance, deflecting criticism, owning limits, showing competence) that suggests differing professional identities and contextual settings. Applications: An attitudinal shift toward accepting and trusting uncertainty in medicine and optometry may facilitate an enriched educational environment for students and a more open dialogue with patients about uncertainty. The unique professional signatures of this rhetoric offer insights into how professional identity shapes attitudes and behaviors toward uncertainty and suggest a source of tension within interdisciplinary healthcare teams.
Healthcare students learn to manage clinical uncertainty amid the tensions that emerge between clinical omniscience and the 'truth for now' realities of the knowledge explosion in healthcare. The case presentation provides a portal to viewing the practitioner's ability to manage uncertainty. We examined the communicative features of uncertainty in 31 novice optometry case presentations and considered how these features contributed to the development of professional identity in optometry students. We also reflected on how these features compared with our earlier study of medical students' case presentations. Optometry students, like their counterparts in medicine, displayed a novice rhetoric of uncertainty that focused on personal deficits in knowledge. While optometry and medical students shared aspects of this rhetoric (seeking guidance and deflecting criticism), optometry students displayed instances of owning limits while medical students displayed instances of proving competence. We found that the nature of this novice rhetoric was shaped by professional identity (a tendency to assume an attitude of moral authority or defer to a higher authority) and the clinical setting (inpatient versus outpatient settings). More explicit discussions regarding uncertainty may help the novice unlock the code of contextual forces that cue the savvy member of the community to sanctioned discursive strategies.
PURPOSE: To examine the performance of various items measuring sexual orientation within 8 school-based adolescent health surveys in the United States and Canada from 1986 through 1999. METHODS: Analyses examined nonresponse and unsure responses to sexual orientation items compared with other survey items, demographic differences in responses, tests for response set bias, and congruence of responses to multiple orientation items; analytical methods included frequencies, contingency tables with Chi-square, and ANOVA with least significant differences (LSD)post hoc tests; all analyses were conducted separately by gender. RESULTS: In all surveys, nonresponse rates for orientation questions were similar to other sexual questions, but not higher; younger students, immigrants, and students with learning disabilities were more likely to skip items or select "unsure." Sexual behavior items had the lowest nonresponse, but fewer than half of all students reported sexual behavior, limiting its usefulness for indicating orientation. Item placement in the survey, wording, and response set bias all appeared to influence nonresponse and unsure rates. CONCLUSIONS: Specific recommendations include standardizing wording across future surveys, and pilot testing items with diverse ages and ethnic groups of teens before use. All three dimensions of orientation should be assessed where possible; when limited to single items, sexual attraction may be the best choice. Specific wording suggestions are offered for future surveys.
Healthcare professionals use the genre of case presentation to communicate among themselves the salient patient information during treatment and management. In case presentation, many uncertainties surface, regarding, e.g., the reliability of patient reports, the sensitivity of laboratory tests, and the boundaries of scientific knowledge. The management and portrayal of uncertainty is a critical aspect of professional discourse. This paper documents the rhetorical features of certainty and uncertainty in novice case presentations, considering their pragmatic and problematic implications for students' professional socialization. This study was conducted during the third-year inpatient clerkship at a tertiary care, pediatric hospital in hospital in Canada. Data collection included: (1) non-participant observations of 19 student case presentations involving 11 student and 10 faculty participants, and (2) individual interviews with 11 students and 10 faculty participants. A grounded theory approach informed data collection and analysis. Five thematic categories emerged, two of which this paper considers in detail: "Thinking as a Student" and "Thinking as a Doctor". Within these categories, the management and portrayal of uncertainty was a recurrent issue. Teachers modeled central features of a "professional rhetoric of uncertainty", managing uncertainty of six origins: limits of individual knowledge, limits of evidence, limitless possibility, limits of patient's/parent's account, limits of professional agreement, and limits of scientific knowledge. By contrast, students demonstrated a "novice rhetoric of uncertainty", represented by their focus on responding to personal knowledge deficits through the strategies of acknowledgement, argument, and deflection. Some students moved towards the professional rhetoric of uncertainty, suggesting not only advances in communication, but also shifts in attitude towards patients and colleagues, that were interpreted as indications th
Healthcare professionals use the genre of case presentation to communicate among themselves the salient patient information during treatment and management. In case presentation, many uncertainties surface, regarding, e.g., the reliability of patient reports, the sensitivity of laboratory tests, and the boundaries of scientific knowledge. The management and portrayal of uncertainty is a critical aspect of professional discourse. This paper documents the rhetorical features of certainty and uncertainty in novice case presentations, considering their pragmatic and problematic implications for students' professional socialization. This study was conducted during the third-year inpatient clerkship at a tertiary care, pediatric hospital in hospital in Canada. Data collection included: (1) non-participant observations of 19 student case presentations involving 11 student and 10 faculty participants, and (2) individual interviews with 11 students and 10 faculty participants. A grounded theory approach informed data collection and analysis. Five thematic categories emerged, two of which this paper considers in detail: "Thinking as a Student" and "Thinking as a Doctor". Within these categories, the management and portrayal of uncertainty was a recurrent issue. Teachers modeled central features of a "professional rhetoric of uncertainty", managing uncertainty of six origins: limits of individual knowledge, limits of evidence, limitless possibility, limits of patient's/parent's account, limits of professional agreement, and limits of scientific knowledge. By contrast, students demonstrated a "novice rhetoric of uncertainty", represented by their focus on responding to personal knowledge deficits through the strategies of acknowledgement, argument, and deflection. Some students moved towards the professional rhetoric of uncertainty, suggesting not only advances in communication, but also shifts in attitude towards patients and colleagues, that were interpreted as indications th
In response to the preceding commentary by Jerry Menikoff in this issue of the Journal, the authors argue that Fried's central concern is not that randomized clinical trials (RCTs) are conducted without consent, but rather that various aspects of the design and conduct of RCTs are in tension with physicians' duties of personal care to their patients. Although Fried does argue that the existence of equipoise cannot justify failure to obtain consent from research subjects, informed consent by itself does not supplant ill subjects' rights to personalized judgment and care embodied in Fried's equipoise.
When may a physician legitimately offer enrollment in a randomized clinical trial (RCT) to her patient? Two answers to this question have had a profound impact on the research ethics literature. Equipoise, as originated by Charles Fried, which we term Fried's equipoise (FE), stipulates that a physician may offer trial enrollment to her patient only when the physician is genuinely uncertain as to the preferred treatment. Clinical equipoise (CE), originated by Benjamin Freedman, requires that there exist a state of honest, professional disagreement in the community of expert practitioners as to the preferred treatment. FE and CE are widely understood as competing concepts. We argue that FE and CE offer separable and, in themselves, incomplete justifications for the conduct of clinical trials. FE articulates conditions under which the fiduciary duties of physician to patient may be upheld in the conduct of research. CE sets out a standard for the social approval of research by institutional review boards. Viewed this way, FE and CE are not necessarily competing notions, but rather address complementary moral concerns.
Presents the findings of research relating to the 1990 Hagersville (Ontario) tire fire. After reviewing the literature on risk and risk perception, the fire and the community in which it occurred are described. The practical, conceptual, and methodological reasons for adopting a qualitative research design are then established. 43 residents' accounts of the fire, evacuation, and aftermath in terms of concerns, anxieties, and responses are described. Five themes emerged: economic, community, health, environmental, and governance. A case study-derived model of risk appraisal and management is discussed.
