Showing papers by "University of Western Ontario published in 1995"

Computer self-efficacy: development of a measure and initial test

Abstract: This paper discusses the role of individuals' beliefs about their abilities to competently use computers (computer self-efficacy) in the determination of computer use. A survey of Canadian managers and professionals was conducted to develop and validate a measure of computer self-efficacy and to assess both its impacts and antecedents. Computer self- efficacy was found to exert a significant influence on individuals' expectations of the outcomes of using computers, their emotional reactions to computers (affect and anxiety), as well as their actual computer use. An individual's self-efficacy and outcome expecta- tions were found to be positively influenced by the encouragement of others in their work group, as well as others' use of computers. Thus, self-efficacy represents an important individual trait, which moderates organizational influences (such as encouragement and support) on an individual's decision to use computers. Understanding self-efficacy, then, is important to the successful implementation of systems in organizations. The existence of a reliable and valid measure of self-efficacy makes assessment possible and should have implications for organizational support, training, and implementation.

The visual brain in action

Abstract: Prologue 1. Introduction: vision from a biological point of view 2. Visual processing in the primate visual cortex 3. 'Cortical blindness' 4. Disorders of spatial perception and the visual control of action 5. Disorders of visual recognition 6. Dissociations between perception and action in normal subjects 7. Attention, consciousness, and the coordination of behaviour 8. Epilogue: twelve years on

Effective physician-patient communication and health outcomes: a review

Abstract: OBJECTIVE: To ascertain whether the quality of physician-patient communication makes a significant difference to patient health outcomes. DATA SOURCES: The MEDLINE database was searched for articles published from 1983 to 1993 using "physician-patient relations" as the primary medical subject heading. Several bibliographies and conference proceedings were also reviewed. STUDY SELECTION: Randomized controlled trials (RCTs) and analytic studies of physician-patient communication in which patient health was an outcome variable. DATA EXTRACTION: The following information was recorded about each study: sample size, patient characteristics, clinical setting, elements of communication assessed, patient outcomes measured, and direction and significance of any association found between aspects of communication and patient outcomes. DATA SYNTHESIS: Of the 21 studies that met the final criteria for review, 16 reported positive results, 4 reported negative (i.e., nonsignificant) results, and 1 was inconclusive. The quality of communication both in the history-taking segment of the visit and during discussion of the management plan was found to influence patient health outcomes. The outcomes affected were, in descending order of frequency, emotional health, symptom resolution, function, physiologic measures (i.e., blood pressure and blood sugar level) and pain control. CONCLUSIONS: Most of the studies reviewed demonstrated a correlation between effective physician-patient communication and improved patient health outcomes. The components of effective communication identified by these studies can be used as the basis both for curriculum development in medical education and for patient education programs. Future research should focus on evaluating such educational programs.

An Integrated Model of Buyer-Seller Relationships:

Abstract: Relationships in business markets are increasingly important in many companies’ operating strategies. A five-stage framework integrates the constructs most often examined in empirical relationship research with the stages of relationship development (partner selection, defining purpose, setting relationship value, and relationship maintenance). The proposed model recognized that a variable may be active at certain stages and become latent in others. Research directions are proposed and managerial implications discussed.

Unraveling the effects of potassium metasomatism in sedimentary rocks and paleosols, with implications for paleoweathering conditions and provenance

Abstract: Lutites are commonly metasomatized during diagenesis, but the analysis presented here accounts for most postdepositional change. Potassium metasomatism is particularly common, and typically involves the conversion of kaolin (residual weathering product) to illite by reaction with K + -bearing pore waters. Sandstones also undergo K metasomatism, which involves the replacement of plagioclase by potassium feldspar. These changes can be identified petrographically and are quantitatively accounted for by techniques discussed herein. Bulk chemical analyses and ternary diagrams are used to determine the amount of K addition, premetasomatized sediment composition, and composition of provenance areas. The premetasomatized mineralogy of paleosols can be compared with the mineralogy of recent soil profiles and thus, climate and topographic conditions determined for past weathering events. Some weathering indices lead to erroneous conclusions because, by excluding K 2 O from consideration, correction cannot be made for metasomatic effects.

Application of Social Cognitive Theory to Training for Computer Skills

Abstract: While computer training is widely recognized as an essential contributor to the productive use of computers in organizations, very little research has focused on identifying the processes through which training operates, and the relative effectiveness of different methods for such training. This research examined the training process, and compared a behavior modeling training program, based on Social Cognitive Theory Bandura [Bandura, A. 1977. Self-efficacy: Toward a unifying theory of behavioral change. Psych. Rev.842 191--215; Bandura, A. 1978. Reflections on self-efficacy. Adv. Behavioral Res. Therapy1 237--269; Bandura, A. 1982. Self-efficacy mechanism in human agency. Amer. Psychologist372 122--147; Bandura, A. 1986. Social Foundations of Thought and Action. Prentice-Hall, Englewood Cliffs, NJ.], to a more traditional, lecture-based program. According to Social Cognitive Theory, watching others performing a behavior, in this case interacting with a computer system, influences the observers' perceptions of their own ability to perform the behavior, or self-efficacy, and the expected outcomes that they perceive, as well as providing strategies for effective performance. The findings provide only partial support for the research model. Self-efficacy exerted a strong influence on performance in both models. In addition, behavior modeling was found to be more effective than the traditional method for training in Lotus 1-2-3, resulting in higher self-efficacy and higher performance. For WordPerfect, however, modeling did not significantly influence performance. This finding was unexpected, and several possible explanations are explored in the discussion. Of particular surprise were the negative relationships found between outcome expectations and performance. Outcome expectations were expected to positively influence performance, but the results indicated a strong negative effect. Measurement limitations are presented as the most plausible explanation for this result, but further research is necessary to provide conclusive explanations.

The computation of optical flow

Abstract: Two-dimensional image motion is the projection of the three-dimensional motion of objects, relative to a visual sensor, onto its image plane. Sequences of time-orderedimages allow the estimation of projected two-dimensional image motion as either instantaneous image velocities or discrete image displacements. These are usually called the optical flow field or the image velocity field. Provided that optical flow is a reliable approximation to two-dimensional image motion, it may then be used to recover the three-dimensional motion of the visual sensor (to within a scale factor) and the three-dimensional surface structure (shape or relative depth) through assumptions concerning the structure of the optical flow field, the three-dimensional environment, and the motion of the sensor. Optical flow may also be used to perform motion detection, object segmentation, time-to-collision and focus of expansion calculations, motion compensated encoding, and stereo disparity measurement. We investigate the computation of optical flow in this survey: widely known methods for estimating optical flow are classified and examined by scrutinizing the hypothesis and assumptions they use. The survey concludes with a discussion of current research issues.

Cardiac malformation in neonatal mice lacking connexin43

Abstract: Gap junctions are made up of connexin proteins, which comprise a multigene family in mammals. Targeted mutagenesis of connexin43 (Cx43), one of the most prevalent connexin proteins, showed that its absence was compatible with survival of mouse embryos to term, even though mutant cell lines showed reduced dye coupling in vitro. However, mutant embryos died at birth, as a result of a failure in pulmonary gas exchange caused by a swelling and blockage of the right ventricular outflow tract from the heart. This finding suggests that Cx43 plays an essential role in heart development but that there is functional compensation among connexins in other parts of the developing fetus.

Patient-Centered Medicine: Transforming the Clinical Method

Abstract: Preface. About the authors. List of contributors. Acknowledgments. Part one: overview. Introduction. The evolution of clinical method. Part two: the four components of the patient-centered clinical method. Introduction. The first component: exploring health, disease and the illness experience. 'I don't want to die': case illustrating component 1. 'I should write a letter to the editor!': case illustrating component. The second component: understanding the whole person. Part 1: individual and family. Trauma, tragedy, trust and triumph: case illustrating component 2. The second component: understanding the whole person. Part 2: context. Mary T: case illustrating component 2. 'Doctor, I need you to give me a test to check if I am a lesbian': case illustrating component 2. The third component: finding common ground. 'I'd sooner take my chances!': case illustrating component 3. The fourth component: enhancing the patient-clinician relationship. When we first saw eye to eye: case illustrating component 4. The flag for undefined pain: case illustrating component 4. Part 3: learning and teaching the patient-centered clinical method. Introduction. Becoming a physician: the human experience of medical education. A messenger: case illustrating becoming a physician. Learner-centered teaching. Being there: case illustrating being learner-centered. Challenges in learning and teaching the patient-centered clinical method. Teaching the patient-centered clinical method - practical tips. The case report as a teaching tool for patient-centered care. Margaret L: case illustrating a patient-centered case report. Part 4: the health care context and patient-centered care. Introduction. Team-centered approach: how to build and sustain a team. The team was the container for her story: case illustrating a team-centered approach. Health care costs and patient-centered care. Part 5: research on patient-centered care. Introduction. Using qualitative methodologies to illuminate patient-centered care. Evidence on the impact of patient-centered care. Measuring patient perceptions of patient-centeredness. Measuring patient-centeredness. Conclusions. References. Index.

Chronic Rapid Atrial Pacing Structural, Functional, and Electrophysiological Characteristics of a New Model of Sustained Atrial Fibrillation

Abstract: Background Despite the clinical importance of atrial fibrillation (AF), the development of chronic nonvalvular AF models has been difficult. Animal models of sustained AF have been developed primarily in the short-term setting. Recently, models of chronic ventricular myopathy and fibrillation have been developed after several weeks of continuous rapid ventricular pacing. We hypothesized that chronic rapid atrial pacing would lead to atrial myopathy, yielding a reproducible model of sustained AF. Methods and Results Twenty-two halothane-anesthetized mongrel dogs underwent insertion of a transvenous lead at the right atrial appendage that was continuously paced at 400 beats per minute for 6 weeks. Two-dimensional echocardiography was performed in 11 dogs to assess the effects of rapid atrial pacing on atrial size. Atrial vulnerability was defined as the ability to induce sustained repetitive atrial responses during programmed electrical stimulation and was assessed by extrastimulus and burst-pacing techniqu...

Assessing the Case for Social Experiments

Abstract: Rs ecent academic debates pit two alternative approaches to policy evaluation against one another. The first is the "experimental" approach, based on the random assignment of accepted program applicants to a recipient, or treatment, group and a non-recipient, or control, group. The second is the "nonexperimental," or "econometric," approach that uses a variety of microdata sources, statistical methods, and behavioral models to compare the outcomes of participants in social programs with those of nonparticipants. The central question addressed in this paper is whether or not randomized social experiments aid in securing answers to basic questions about the evaluation of social programs. There are many distinct and complementary approaches to the study of the impact of public policy, including full general equilibrium analysis of policy impacts (Tinbergen, 1956; Auerbach and Kotlikoff, 1987; Shoven and Whalley, 1992; Kydland and Prescott, 1991) and less ambitious partial equilibrium microeconomic structural research programs, such as those designed to estimate the impact of taxes on labor supply. Both approaches offer answers to many interesting counterfactual policy questions, but their credibility rests critically on the quality of the empirical input used to generate their answers

Methotrexate for the Treatment of Crohn's Disease

Abstract: Background Although corticosteroids are highly effective in improving symptoms of Crohn's disease, they may have substantial toxicity. In some patients, attempts to discontinue corticosteroids are ...

Radiation Therapy Oncology Group (RTOG) 88–08 and Eastern Cooperative Oncology Group (ECOG) 4588: Preliminary Results of a Phase III Trial in Regionally Advanced, Unresectable Non-Small-Cell Lung Cancer

Abstract: Background: Regionally advanced, surgically unresectable non-small-cell lung cancer represents a disease with an extremely poor prognosis. External-beam irradiation to the primary tumor and regional lymphatics is generally accepted as standard therapy. The use of more aggressive radiation regimens and the addition of cytotoxic chemotherapy to radiotherapy have yielded conflicting results. Recently, however, results from clinical trials using innovative irradiation delivery techniques or chemotherapy before irradiation have indicated that patients treated with protocols that incorporate these modifications may have higher survival rates than patients receiving standard radiation therapy. Purpose: On the basis of these results, the Radiation Therapy Oncology Group (RTOG)-Eastern Cooperative Oncology Group (ECOG) elected to conduct a phase III trial comparing the following regimens: 1) standard radiation therapy, 2) induction chemotherapy followed by standard radiation therapy, and 3) twice-daily radiation therapy. Methods: Patients with surgically unresectable stage II, IIIA, or IIIB non-small-cell lung cancer were potential candidates. Staging was nonsurgical. Patients were required to have a Karnofsky performance status of 70 or more and weight loss less than 5% for 3 months prior to entry into the trial, to be older than 18 years of age, and to have no metastatic disease. Of the 490 patients registered in the trial, 452 were eligible. The disease in 95% of the patients was stage IIIA or IIIB. More than two thirds of the patients had a Karnofsky performance status of more than 80. Patients were randomly assigned to receive either 60 Gy of radiation therapy delivered at 2 Gy per fraction, 5 days a week, over a 6-week period (standard radiation therapy); induction chemotherapy consisting of cisplatin (100 mg/m 2 ) on days 1 and 29 and 5 mg/m 2 vinblastine per week for 5 consecutive weeks beginning on day 1 with cisplatin, followed by standard radiation therapy starting on day 50; or 69.6 Gy delivered at 1.2 Gy per fraction twice daily (hyperfractionated radiation therapy). Results: Toxicity was acceptable, with four treatment-related deaths. Three patients subsequently died of chronic pulmonary complications. Compliance with protocol treatment was acceptable. One-year survival (%) and median survival (months) were as follows: standard radiation therapy-46%, 11.4 months; chemotherapy plus radiotherapy-60%, 13.8 months; and hyperfractionated radiation therapy-51%, 12.3 months. The chemotherapy plus radiotherapy arm was statistically superior to the other two treatment arms (logrank P=.03). Conclusions: In «good-risk» patients with surgically unresectable non-small-cell lung cancer, induction chemotherapy followed by irradiation was superior to hyperfractionated radiation therapy or standard radiation therapy alone, yielding a statistically significant short-term survival advantage

Expanding the Motivation Construct in Language Learning

Abstract: Recent reviews by Crookes & Schmidt (1991), Dornyei (1994), and Oxford and Shearin (1994) have suggested that research concerned with motivation in second language acquisition would benefit from a consideration of motivational constructs from other research areas. The present study addresses this issue by investigating the relation of a number of new measures of motivation such as persistence, attention, goal specificity, and causal attributions to each other, to existing measures of attitudes and motivation, and to indices of achievement in French courses. A sample of 75 students in a francophone secondary school completed various motivational and attitudinal measures, and subsequently wrote a French essay. Their final grades in the French course were later obtained from the school records. Support was found for a LISREL structural equation model linking different aspects of motivation with language attitudes, French language dominance, and French achievement. It was concluded that the new motivational measures add to our understanding of motivation in language learning.

A genetic basis for familial aggregation in multiple sclerosis

Abstract: Genetic-environmental interactions probably underlie spontaneous human autoimmune disorders, a category of complex traits thought to include multiple sclerosis (MS). The geographical distribution and familial aggregation of this disease have often been ascribed to the role of infectious agents, but there is no consensus. Increased family risks range from 300-fold for monozygotic twins to 20-40-fold for biological first-degree relatives over the general population prevalence of 0.1% (ref. 6). We screened a population-based sample of 15,000 individuals with MS by using standardized, personally administered questionnaires to identify adopted index cases and/or those who had adopted relatives. The frequency of MS among first-degree non-biological relatives living with the index case was no greater than expected from Canadian population prevalence data and significantly less than for biological relatives. These findings indicate that familial aggregation of MS is genetically determined: no effect of shared environment was detectable.

Believing Is Seeing: Joint Ventures and Organization Learning*

Abstract: This paper develops a conceptual framework for the study of organization learning and applies it to learning in joint ventures (JVs). the framework presents a multilevel view of the phenomenon, suggesting that learning in organizations occurs at the individual, group and organization levels. the framework integrates behavioural and cognitive perspectives of organization learning and delineates both learning processes and outcomes. Four key elements of organization learning are addressed: the nature of managerial learning experiences, the sharing and integration of managerial learning within an organization, the insti-tutionalization of learning, and the relationship between organization learning and performance. In applying the framework to a study of learning and JVs, we observed firms with explicit learning objectives unable to put into place the appropriate mechanisms and systems to transfer knowledge from the JV to the parent. While individual managers in the JVs were often enthusiastic and positive about their learning experiences, integration of the learning experience at the parent firm level was problematic, limiting the institutionalized learning. the fundamental position in this paper is that a rigid set of managerial beliefs associated with an unwillingness to cast off or unlearn past practices can severely limit the effectiveness of organization learning.

BOLD based functional MRI at 4 Tesla includes a capillary bed contribution: echo-planar imaging correlates with previous optical imaging using intrinsic signals

Abstract: We show that the EPI time course in functional MR imaging at 4 Tesla displays a multiphasic response in response to photic stimulation. Focal areas of gray matter display an initial negative change in signal intensity that reaches a maximum of 1 % about 2 s after the onset of photic stimulation. This component then changes sign, reaching a positive maximum about 5 s after the onset of the stimulus. Other areas, including those where draining veins are visible, show only a positive signal change, reaching a maximum of about 6% after the onset of the visual stimulus. These time constants are in very good agreement with published data obtained with intrinsic optical mapping techniques, where a deoxygenation phase has been shown to occur in functionally specific cortical columns, followed by an increase in blood volume which is more distributed in nature. Thus, we believe there is strong evidence that a sensitivity to capillary oxygenation state is present in high S/N functional MR images obtained with EPI at 4 T.

Structural and competitive determinants of a global integration strategy

Abstract: Both structural determinants and competitive factors can work to define the relevant environment for strategy formulation within an industry. This study examines the effects of each of these two sets of factors on global integration strategies, and finds that their impacts vary considerably from one industry to another. The study also investigates the relationship between a business's global integration strategy and its performance, using an industry-specific perspective. In the aggregate, the businesses studied appear to be under-globalized. However, this relationship varied significantly by industry ; four of the industries studied appeared to be under-globalized, while the remaining three industries were at or near an optimal level of globalization.

Taxonomic Note: Implementation of the Provisional Status Candidatus for Incompletely Described Procaryotes

Abstract: The International Committee on Systematic Bacteriology recommended that the category Candidatus, recently proposed by Murray and Schleifer (Int. J. Syst. Bacteriol. 44:174-176,1994) to record the properties of putative taxa of procaryotes, should be implemented. This category should be used for describing procaryotic entities for which more than a mere sequence is available but for which characteristics required for description according to the International Code of Nomenclature of Bacteria are lacking. In addition to genomic information, such as sequences apt to determine the phylogenetic position of the organism, all information, including structural, metabolic, and reproductive features, should be included in the description of a provisional taxon, together with the natural environment in which the organism can be identified by in situ hybridization or other similar techniques for cell identification.

Organizational learning: dimensions for a theory

Abstract: Organizational learning (OL) is receiving increasing attention from researchers and practitioners alike. In fact, some have suggested that the only sustainable competitive advantage is a firm's ability to learn faster than its competitors. In spite of OL's promise, the field has been slow to evolve. The primary impediments to the development of OL theory are that inconsistent terminology is used for comparable concepts and that different definitions are used to describe the phenomenon. Furthermore, many theorists have neglected to make explicit their underlying assumptions about the phenomenon. Employing an inductive approach, this review surfaces the implicit and explicit assumptions of OL researchers, identifying three key dimensions that differentiate perspectives: (1) unit of analysis—individual, group, organizational, and inter organizational; (2) cognitive/behavioral emphasis; and (3) the learning‐performance relationship.

Spatial learning without NMDA receptor-dependent long-term potentiation.

Abstract: Hippocampal lesions impair spatial learning in the watermaze. Drugs that antagonize N-methyl-D-aspartate (NMDA)-receptor activity, which is required for long-term potentiation (LTP) at various hippocampal synapses, block LTP and impair watermaze learning. This has led to the hypothesis that NMDA receptors, through their involvement in LTP, may be necessary for spatial and other forms of learning. We examined this hypothesis using NPC17742 (2R,4R,5S-2-amino-4,5-(1,2-cyclo hexyl)-7-phosphonoheptano acid), a potent and specific antagonist of NMDA receptors. Here we report that NPC17742 completely blocked dentate gyrus LTP but did not prevent normal spatial learning in rats that had been made familiar with the general task requirements by non-spatial pretraining. Although these results do not rule out a contribution of NMDA-mediated dentate LTP to spatial learning, they indicate that this form of LTP is not required for normal spatial learning in the watermaze.

Long-term prognosis and effect of endarterectomy in patients with symptomatic severe carotid stenosis and contralateral carotid stenosis or occlusion: results from NASCET. North American Symptomatic Carotid Endarterectomy Trial (NASCET) Group.

Abstract: The purpose of this study was to examine how the prognosis of patients who presented with a recent ischemic event referable to a 70% to 99% stenosis of one carotid artery (ipsilateral) was altered by stenosis and occlusion of the contralateral carotid artery The benefit of performing carotid endarterectomy on the recently symptomatic artery, in the presence of contralateral artery disease, was also examined A total of 659 patients were grouped into one of three categories according to the extent of stenosis in the contralateral carotid artery: less than 70% (559 patients), 70% to 99% (57 patients), and occlusion (43 patients) Strokes that occurred during the follow-up period were designated as ipsilateral if they arose from the same carotid artery as the symptom for which the patient had been entered into the study Medically treated patients with an occluded contralateral artery were more than twice as likely to have had an ipsilateral stroke at 2 years than patients with either severe (hazard ratio: 236; 95% confidence interval (CI): 100-562) or mild-to-moderate (hazard ratio: 265; 95% CI: 143-490) contralateral artery stenosis The perioperative risk of stroke and death was higher in patients with an occluded contralateral artery (40% risk) or mild-to-moderate (51% risk) contralateral stenosis Regression analyses indicated that the results were not affected by other risk factors An occluded contralateral carotid artery significantly increased the risk of stroke associated with a severely stenosed ipsilateral carotid artery Despite higher perioperative morbidity in the presence of an occluded contralateral artery, the longer-term outlook for patients who had endarterectomy performed on the recently symptomatic, severely stenosed ipsilateral carotid artery was considerably better than for medically treated patients

Biological guidelines for freshwater sediment based on BEnthic Assessment of SedimenT (the BEAST) using a multivariate approach for predicting biological state

Abstract: This paper describes the first results for an alternative approach to the development of sediment quality criteria in the nearshore areas of the Laurentian Great Lakes. The approach is derived from methods developed in the United Kingdom for establishing predictive relationships between macroinvertebrate fauna and the physico-chemistry of riverine environments. The technique involves a multivariate statistical approach using (i) data on the structure of benthic invertebrate communities, (ii) functional responses (survival, growth and reproduction) in four sediment toxicity tests (bioassays) with benthic invertebrates; and (iii) selected environmental variables at 96 reference (‘clean’) sites in the nearshore areas of all five Great Lakes (Lakes Superior, Huron, Erie, Ontario and Michigan). Two pattern recognition techniques (using the computer software package PATN) are employed in the analysis: cluster analysis and ordination. The ordination vector scores from the original axes of the pattern analysis are correlated (using CORR in SAS) with environmental variables which are anticipated to be least affected by anthropogenic activities (e. g. alkalinity, depth, silt, sodium etc.). Multiple discriminant analysis (MDA) is used to relate the site groupings from the pattern analysis to the environmental variables and to generate a model that can be used to predict community assemblages and functional responses at new sites with unknown but potential contamination. The predicted community assemblages and functional responses are then compared with the actual benthic communities and responses at a site, and the need for remedial action is determined. The predictive capability of the discriminant model was confirmed by performing several validation runs on subsets of the data. An example of the use of the model for sediment in Collingwood Bay (an area of concern designated by the IJC in Georgian Bay, Lake Huron) is presented and the technique is shown to be more precise in determining the need for remediation than the currently used provincial sediment quality criteria based on Screening Level Concentration (SLC) and laboratory toxicity tests. The ultimate goal of the study is the development of a method to determine the need for, and the success of, remedial action and to predict what benthic communities should look like at a site if it were clean and what responses of organisms in sediment toxicity tests constitute an acceptable end-point.