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Biomedical subjects

Peter Harris

Publications and source records attributed to Peter Harris.

15 recordsLinked to original sources
PubMed2006

The use of a Monte Carlo method for uncertainty calculation, with an application to the measurement of neutron ambient dose equivalent rate.

This paper is concerned with the use of a Monte Carlo method for uncertainty calculation as an implementation of the propagation of distributions. It reviews the basic principles of the propagation of distributions and numerical aspects of a Monte Carlo implementation. It also discusses the possible advantages in some circumstances of the propagation of distributions over the GUM uncertainty framework, and how the results obtained in any particular instance can be compared with those provided by that framework. To illustrate these various aspects, an application to the measurement of neutron dose equivalent rate is given. A key consideration in this application is the manner in which the dominant source of uncertainty, namely that associated with the field-specific correction factor, is treated. The information available concerning this factor constitutes the correction factors for a set of fields of the same type as that in which a measurement is being made. This information is encoded as a probability density function (PDF) for the correction factor. This PDF constitutes an input to both methods of evaluation.

Anisotropy↗
PubMed2006

Depression--what should the doctor ask?

BACKGROUND: There are barriers to doctors detecting depression in general practice. We wondered what questions patients thought the doctor should ask to explore it appropriately. METHODS: One hundred and thirty-six teacher trainees, teachers, and students in the community, most of whom had experienced depression, were studied qualitatively in interviews and focus groups. They were asked to suggest what questions they would find helpful from doctors to elicit their experience of depression. Transcripts were grouped by gender and content analysed. RESULTS: Subjects suggested starting with open questions that act as signals for moving into emotional areas followed by specific questions about specific somatic expressions of depression. Men preferred questions about shorter fuse and anger toward others, while women were happy with questions about increased crying. DISCUSSION: If confirmed in other sectors of the community, these data may allow doctors to increase patients' comfort with their exploration of possible emotional problems such as depression.

Australia↗
PubMed2005

Adherence to an exercise prescription scheme: the role of expectations, self-efficacy, stage of change and psychological well-being.

OBJECTIVES: Poor rates of adherence to exercise prescription schemes present a potential barrier to the goal of increasing physical activity in patient samples. This study investigated the role of participant expectations, self-efficacy, stage of change and psychological well-being in adherence to a 12-week course of gym based exercise. It also aimed to assess the impact of failure to adhere on self-efficacy and psychological well-being. METHOD: The 119 participants, referred by their medical practitioner for a course of exercise, completed questionnaires at the start of the course and 77 went on to complete second questionnaires. Objective measures included a range of physiological measures based on gym assessments. RESULTS: Participants typically had high expectations of the scheme. Those who completed the course had more modest expectations of change and came closer to achieving these expected changes than those who dropped out. Initial stage of change and self-efficacy did not discriminate between the two groups. While self-efficacy improved over the scheme for completers, it tended to deteriorate for drop-outs. GHQ scores also failed to improve over time for drop-outs. CONCLUSION: Overly optimistic expectations of inexperienced exercisers may lead to disappointment and attrition. Interventions to ensure realistic expectations might increase success and prevent potential negative effects of failure.

Adaptation, Psychological↗
PubMed2005

Ongoing regulatory compliance required.

New regulations concerning the management of asbestos in non-residential properties came into force in May last year, and this 'Duty to Manage' legislation means that duty holders should be managing their asbestos adequately by fulfilling certain criteria. Inadequate management of asbestos could lead to heavy fines. Special report by Peter Harris, client services manager, Redhill Analysts.

Accreditation↗
PubMed2003

What do students want? The types of learning activities preferred by final year medical students.

CONTEXT: A well-aligned curriculum has consistent focus on curricular goals, teaching/learning activities and assessment. Poor alignment affects the way students budget learning time and may interfere with achievement of curricular goals. We noticed students' poor attendance in clinical clerkships prior to final examinations and hypothesised that they were responding to curricular misalignment. OBJECTIVES: To quantify the extent to which students and tutors perceived a mismatch between activities pertaining to their current clerkship and those they thought necessary to prepare for final examinations and internship. SUBJECTS: Medical students in final (sixth) year clerkships in medicine, surgery and critical care and clinical tutors. METHOD: A self-report questionnaire on time spent in clerkship activities was administered 3 months before the final examinations. RESULTS: The amounts of time spent on current activities were fairly evenly spread over teaching, study and self-directed patient contacts, and observing patient care (ward rounds, operating theatre, accident and emergency, outpatient department and clinical meetings). Less time was available for recreation. Students and tutors concurred, independently, that good examination and internship preparation required a shifting of the balance. Examination preparation redistributed time from observing patient care and recreation to study and self-directed patient contacts. Internship preparation redistributed time from teaching and recreation to observing patient care. CONCLUSION: Students and tutors perceived that current activities were not well aligned with assessment requirements but were better aligned with the requirements of internship. If we want students to direct their attention towards curricular goals, we need to bring goals, teaching/learning activities and assessment into alignment.

Australia↗
PubMed2002

Constitutive activation of G-proteins by polycystin-1 is antagonized by polycystin-2.

Polycystin-1 (PC1), a 4,303-amino acid integral membrane protein of unknown function, interacts with polycystin-2 (PC2), a 968-amino acid alpha-type channel subunit. Mutations in their respective genes cause autosomal dominant polycystic kidney disease. Using a novel heterologous expression system and Ca(2+) and K(+) channels as functional biosensors, we found that full-length PC1 functioned as a constitutive activator of G(i/o)-type but not G(q)-type G-proteins and modulated the activity of Ca(2+) and K(+) channels via the release of Gbetagamma subunits. PC1 lacking the N-terminal 1811 residues replicated the effects of full-length PC1. These effects were independent of regulators of G-protein signaling proteins and were lost in PC1 mutants lacking a putative G-protein binding site. Co-expression with full-length PC2, but not a C-terminal truncation mutant, abrogated the effects of PC1. Our data provide the first experimental evidence that full-length PC1 acts as an untraditional G-protein-coupled receptor, activity of which is physically regulated by PC2. Thus, our study strongly suggests that mutations in PC1 or PC2 that distort the polycystin complex would initiate abnormal G-protein signaling in autosomal dominant polycystic kidney disease.

GTP-Binding Proteins↗
PubMed2002

The impact of working life on health behavior: the effect of job strain on the cognitive predictors of exercise.

The theory of planned behavior (TPB) and R. A. Karasek's (1979) job strain model were used to investigate the predictors of exercise in a group of employees. A total of 241 employees completed an initial questionnaire; 1 week later 213 employees responded to a questionnaire measuring behavior. Employees in high-strain jobs did significantly less exercise than those in low-strain jobs, although they did not intend to do less, suggesting that work may impede the intention implementation. Intenders who failed to exercise had significantly higher work demands and lower exercise self-efficacy than intenders who succeeded in exercising. Work also affected exercise indirectly through self-efficacy. Thus, work may be a target for behavior change intervention because of its impact at 2 stages of the TPB.

Adult↗
PubMed2002

The transition out of medical school - a qualitative study of descriptions of borderline trainee interns.

OBJECTIVE: To describe the characteristics of borderline performance in final year medical students (trainee interns), as judged by their supervisors. DESIGN: Qualitative study based on in-depth interviews followed by validation descriptions of borderline trainee interns identified prospectively over 12 months. SETTING: Christchurch School of Medicine, University of Otago, New Zealand. PARTICIPANTS: Fourteen supervisors of trainee interns chosen because of their experience and/or close contact with trainee interns. MAIN OUTCOME MEASURES: Analysis of supervisors' narratives to identify key themes. RESULTS: Borderline trainee intern performance occurs within a transition period from clinical student to doctor and is characterised by difficulty taking on a professional role. This difficulty may be manifest by not getting involved with the health care team, poor time management and occasionally by interpersonal difficulties or not recognising limits. Taking on a professional role requires ability in the clinical task, including diagnostic ability, which is built on a foundation of basic knowledge and clinical skills. These can be influenced by personal factors such as rigidity, motivation and shyness. Personal illness can affect performance at any stage. CONCLUSIONS: The difficulties faced by borderline trainee interns fit a model of transition from competence as a student to performance as an intern. A sensitive marker of such difficulties is poor time management or not getting involved with the patient care team. Such difficulties may reflect more specific problems such as professional socialization, setting priorities, hypothesis generation, assigning probabilities to identified problems, integrating competing issues, recognising limits and learning when to call for assistance.

Clinical Competence↗
PubMed2002

Residents as teachers: outcomes of a brief training programme.

INTRODUCTION: Residents (RMOs) teach medical students in hospital wards, yet little evidence of efficacy is available for this activity. This study undertook to test the effectiveness of RMO teaching, and to delineate the principal barriers encountered. METHODS: Medical students in their fourth year were assessed at baseline for clinical examination skills in ophthalmoscopy, neurological examination of the legs, and rheumatological examination of the hands. One group of RMOs (n=6) taught ophthalmoscopy to the students attached to their unit, while the second group of RMOs (n=6) taught leg examination to their students. The third examination skill was not taught, but was used as a control intervention. The students were evaluated in all three skills by an observed, structured clinical examination at the beginning and end of their six-week attachments. RESULTS: There was a significant improvement in the skill of ophthalmoscopy in the intervention group (p<0.02), while the control group of students showed a decline in their abilities. The skill of examination of the legs improved after being taught, but not significantly. The RMOs universally reported that difficulty in finding time was a major barrier to their ability to teach medical students, and most set up additional teaching sessions rather than incorporate the teaching into their routine ward work. CONCLUSIONS: RMO teaching of medical students is effective, particularly for a skill which is novel. The difficulties arise in finding a suitable time for these important clinical teachers to transfer their skills.

Journal Article↗
PubMed2002

Multiple stenting in Takayasu arteritis.

PURPOSE: To illustrate the possible peri- and postprocedural complications of stent treatment for Takayasu arteritis and suggest ways of reducing these risks. CASE REPORT: A 69-year-old woman with Takayasu arteritis had multiple stents implanted in the aortic arch (3 Memotherm) and main branches of the thoracic aorta (individual Corinthian stents in the subclavian and brachiocephalic arteries) following balloon dilation. She suffered reperfusion injury with cerebral hemorrhage following the procedure, preventing the use of anticoagulation or antiplatelet therapy. Further cerebral infarctions/hemorrhages over the ensuing months led to her death. CONCLUSIONS: Severe vascular disease of any cause confers a poor prognosis. Endovascular stenting may seem an attractive option for management of these patients, but there is often significant morbidity and mortality associated with the underlying disease as well as the stent.

Aged↗
PubMedDate not supplied

Convergence of techniques for the evaluation of discrepant data.

The problem of evaluating discrepant data has been addressed by several authors over the previous 20 yr. More recently some attention has been given to the use of the median, which is expected to have better statistical 'robustness'. The various evaluation techniques should converge towards the 'true' value as the number of data in a data set increases, and the 'robustness' of each evaluation technique can then be tested by the rate at which that technique converges. Several evaluation techniques have been applied to discrepant data sets, and the results are shown to converge as the size of the data set grows. The discrepant data sets used as examples are the measured half-lives of 90Sr and 137Cs. Differences in the behaviour of the evaluation techniques are discussed, as applied to these data sets. The half-lives deduced from this study are: 90Sr 10,551+/-14 days; 137Cs 10,981+/-11 days.

Cesium Radioisotopes↗