A magnetically collimated jet from an evolved star

Planetary nebulae often have asymmetric shapes, which could arise due to collimated jets from evolved stars before evolution to the planetary nebula phase. The source of jet collimation in these stars is unknown. Magnetic fields are thought to collimate outflows that are observed in many other astrophysical sources, such as active galactic nuclei and proto-stars, although hitherto there are no direct observations of both the magnetic field direction and strength in any collimated jet. Theoretical models have shown that magnetic fields could also be the dominant source of collimation of jet in evolved stars. Here we report measurements of the polarization of water vapour masers that trace the precessing jet emanating from the asymptotic giant branch star W43A at 2.6 kpc from the Sun, which is undergoing rapid evolution into a planetary nebula. The masers occur in two clusters at opposing tips of the jets, ~1,000 AU from the star. We find direct evidence that the magnetic field is collimating the jet.Comment: Published in Nature 440 (March 2nd 2006). High-res figures can be found at http://www.jb.man.ac.uk/~wouter/papers/w43a/w43a.htm

A cross sectional survey of urban Canadian family physicians' provision of minor office procedures

BACKGROUND: A discordance exists between the proportion of Canadian family physicians that we expect should be able to perform minor office procedures and the actual provision of care. This pattern has not been extensively studied. The objective of this study was to determine the current patterns and obstacles relating to the provision of four minor office procedures by GP/FPs in a small city in Ontario, Canada. An additional goal was to determine the impact of the remuneration method on the provision of such services. METHODS: A survey was mailed to all GP/FPs practising in Kingston, Ontario. The main outcomes measured in the study were work setting and remuneration method, current procedural practices with respect to four procedures, reasons for not performing procedures, current skill levels, and desire to upgrade. RESULTS: Surveys were mailed to all 108 GP/FPs in the City of Kingston. Completed surveys were collected for 82 percent (89/108) and 10 were excluded leaving 79 eligible participants. The percentages of GP/FPs who reported performing the procedure were as follows: dermatological excision (63.3%), endometrial biopsy (35.4%), shoulder injection (31.6%), and knee injection (43.0%). The majority of GP/FPs who would not do the procedure themselves would refer to a specialist colleague rather than to another GP/FP. The top reason cited for not performing a specific procedure was "lack of up to date skills" followed by "lack of time". The latter was the only statistically significant difference reported between GP/FPs working in Family Health Networks and GP/FPs working in fee for service settings (26.7% vs 47.0%, χ(2 )= 4.191 p = 0.041). CONCLUSION: A large number of Kingston, Ontario GP/FPs refer patients who require one of four minor office-based procedures for specialist consultation. Referral to other GP/FP colleagues appears underutilized. A perceived lack of up to date skills and a lack of time appear to be concerns. GP/FPs working in Family Health Networks were more likely to perform these procedures themselves. Further studies would clarify the role of changes in medical education, the role of continuing education, and the impact of different remuneration models

Interocular yoking in human saccades examined by mutual information analysis

International audienceABSTRACT : BACKGROUND : Saccadic eye movements align the two eyes precisely to foveate a target. Trial-by-trial variance of eye movement is always observed within an identical experimental condition. This has often been treated as experimental error without addressing its significance. The present study examined statistical linkages between the two eyes' movements, namely interocular yoking, for the variance of eye position and velocity. METHODS : Horizontal saccadic movements were recorded from twelve right-eye-dominant subjects while they decided on saccade direction in Go-Only sessions and on both saccade execution and direction in Go/NoGo sessions. We used infrared corneal reflection to record simultaneously and independently the movement of each eye. Quantitative measures of yoking were provided by mutual information analysis of eye position or velocity, which is sensitive to both linear and non-linear relationships between the eyes' movements. Our mutual information analysis relied on the variance of the eyes movements in each experimental condition. The range of movements for each eye varies for different conditions so yoking was further studied by comparing GO-Only vs. Go/NoGo sessions, leftward vs. rightward saccades. RESULTS : Mutual information analysis showed that velocity yoking preceded positional yoking. Cognitive load increased trial variances of velocity with no increase in velocity yoking, suggesting that cognitive load may alter neural processes in areas to which oculomotor control is not tightly linked. The comparison between experimental conditions showed that interocular linkage in velocity variance of the right eye lagged that of the left eye during saccades. CONCLUSIONS : We conclude quantitative measure of interocular yoking based on trial-to-trial variance within a condition, as well as variance between conditions, provides a powerful tool for studying the binocular movement mechanism

Developing health science students into integrated health professionals: a practical tool for learning

BACKGROUND:An integrated sense of professionalism enables health professionals to draw on relevant knowledge in context and to apply a set of professional responsibilities and ethical principles in the midst of changing work environments 12. Inculcating professionalism is therefore a critical goal of health professional education. Two multi-professional courses for first year Health Science students at the University of Cape Town, South Africa aim to lay the foundation for becoming an integrated health professional 3. In these courses a diagram depicting the domains of the integrated health professional is used to focus the content of small group experiential exercises towards an appreciation of professionalism. The diagram serves as an organising framework for conceptualising an emerging professional identity and for directing learning towards the domains of 'self as professional' 45.OBJECTIVE:This paper describes how a diagrammatic representation of the core elements of an integrated health professional is used as a template for framing course content and for organising student learning. Based on the assumption that all health care professionals should be knowledgeable, empathic and reflective, the diagram provides students and educators with a visual tool for investigating the subjective and objective dimensions of professionalism. The use of the diagram as an integrating point of reference for individual and small group learning is described and substantiated with relevant literature. CONCLUSION: The authors have applied the diagram with positive impact for the past six years with students and educators reporting that "it just makes sense". The article includes plans for formal evaluation. Evaluation to date is based on preliminary, informal feedback on the value of the diagram as a tool for capturing the domains of professionalism at an early stage in the undergraduate education of health professional students

The Dynamical Structure and Evolution of Giant Molecular Clouds

Giant molecular clouds (GMCs) are the sites of star formation in the Galaxy. Many of their properties can be understood in terms of a model in which the GMCs and the star-forming clumps within them are in approximate pressure equilibrium, with turbulent motions treated as a separate pressure component