Are medical students influenced by preceptors in making career choices, and if so how? A systematic review.

INTRODUCTION: Increasingly medical students undertake clinical training in distributed learning environments. The driving factor for this is predominantly to address medical workforce shortages. In these environments students are often taught by private practitioners, residents, house staff and registrars, as well as faculty. Through a mix of short- and long-term preceptorships, clerkships and rotations, medical students are exposed to a wider range of preceptors, mentors and role models than has traditionally been the case. The aim of this systematic review was to understand if and how medical students' career choices are influenced by their interactions with preceptors. METHOD: A search of Ovid Medline, Scopus, ISI Web of Science, PubMed, Eric and CIHNAL was undertaken. The search was structured around the key terms: Medical Student, Career Choice and Preceptor, and variants of these terms. Search limits were set to English-language publications between 1995 and 2010. RESULTS: A total of 36 articles met the selection criteria from the 533 citations sourced from the search. Required preceptorships as short as 3 weeks' duration influence the career choice of students when they rate the preceptor as a high quality teacher. Preceptors who are judged (by students) as high quality teachers have the greatest influence on student career choice by up to four-fold. When students judged a preceptor as being a negative role model, a poor teacher or lacking discipline specific knowledge they will turn away from that field. The positive influence of relationships between preceptors and students on career choice is strongest where there is continuity of preceptors, continuity of care, and continuity of patient interactions. The longer the duration of the preceptorship the greater the influence on student career choice, particularly in primary cares environments. CONCLUSION: This review adds to the literature by identifying how differing components and combinations of components of a preceptorship influence medical student career choices. Multiple components of the preceptorship combined have a greater influence. In free choice, longitudinal integrated clerkships' duration of placement and continuity relationships with preceptors have the greatest influence on medical students in pursuing a primary care career. This information informs medical schools, curriculum designers and policy-makers in reforming medical education to address workforce shortages.

One or more bound planets per Milky Way star from microlensing observations.

Most known extrasolar planets (exoplanets) have been discovered using the radial velocity or transit methods. Both are biased towards planets that are relatively close to their parent stars, and studies find that around 17-30% (refs 4, 5) of solar-like stars host a planet. Gravitational microlensing, on the other hand, probes planets that are further away from their stars. Recently, a population of planets that are unbound or very far from their stars was discovered by microlensing. These planets are at least as numerous as the stars in the Milky Way. Here we report a statistical analysis of microlensing data (gathered in 2002-07) that reveals the fraction of bound planets 0.5-10 AU (Sun-Earth distance) from their stars. We find that 17(+6)(-9)% of stars host Jupiter-mass planets (0.3-10 M(J), where M(J) = 318 M(⊕) and M(⊕) is Earth's mass). Cool Neptunes (10-30 M(⊕)) and super-Earths (5-10 M(⊕)) are even more common: their respective abundances per star are 52(+22)(-29)% and 62(+35)(-37)%. We conclude that stars are orbited by planets as a rule, rather than the exception.

A new model to understand the career choice and practice location decisions of medical graduates.

INTRODUCTION: Australian medical education is increasingly influenced by rural workforce policy. Therefore, understanding the influences on medical graduates' practice location and specialty choice is crucial for medical educators and medical workforce planners. The South Australian Flinders University Parallel Rural Community Curriculum (PRCC) was funded by the Australian Government to help address the rural doctor workforce shortage. The PRCC was the first community based medical education program in Australia to teach a full academic year of medicine in South Australian rural general practices. The aim of this research was to identify what factors influence the career choices of PRCC graduates. METHODS: A retrospective survey of all contactable graduates of the PRCC was undertaken. Quantitative data were analysed using SPSS 14.0 for Windows. Qualitative data were entered into NVIVO 7 software for coding, and analysed using content analysis. RESULTS: Usable data were collected from 46 of the 86 contactable graduates (53%). More than half of the respondents (54%) reported being on a rural career path. A significant relationship exists between being on a rural career pathway and making the decision prior to or during medical school (p = 0.027), and between graduates in vocational training who are on an urban career path and making a decision on career specialty after graduation from medical school (p = .004). Graduates in a general practice vocational training program are more likely to be on a rural career pathway than graduates in a specialty other than general practice (p = .003). A key influence on graduates' practice location is geographic location prior to entering medical school. Key influences on graduates choosing a rural career pathway are: having a spouse/partner with a rural background; clinical teachers and mentors; the extended rural based undergraduate learning experience; and a specialty preference for general practice. A lack of rural based internships and specialist training places is influencing both urban- and rural-origin graduates to practise in urban locations. Further analysis of graduates' career pathway choices (rural or urban) and geographic background (rural or urban) was conducted. This resulted in the development of a new model, 'The Four Qs Model'. This model consists of four quadrants derived from the variables career pathway choice (rural or urban) and geographic background (rural or urban). Clustering of consistent demographic and qualitative trends unique to each quadrant was demonstrated. The distinctive clustering that emerged from the data resulted in the quadrants being renamed 'The True Believers', 'The Convertibles' 'The Frustrated' and 'The Metro Docs'. CONCLUSIONS: The PRCC is influencing graduates to choose a rural career path. The PRCC program affirms the career preferences of rural origin students while graduates with little rural exposure prior to the PRCC report being positively influenced to pursue a rural career path. The Four Qs Model is a useful model in that it demonstrates consistent themes in the characteristics of PRCC graduates and assists understanding of why they choose a rural medical career. This could be relevant to the selection of medical students into rural medical education programs and in the construction of rural curricula. The model also offers a useful framework for further research in this field.

Discovery of a cool planet of 5.5 Earth masses through gravitational microlensing.

In the favoured core-accretion model of formation of planetary systems, solid planetesimals accumulate to build up planetary cores, which then accrete nebular gas if they are sufficiently massive. Around M-dwarf stars (the most common stars in our Galaxy), this model favours the formation of Earth-mass (M(o)) to Neptune-mass planets with orbital radii of 1 to 10 astronomical units (au), which is consistent with the small number of gas giant planets known to orbit M-dwarf host stars. More than 170 extrasolar planets have been discovered with a wide range of masses and orbital periods, but planets of Neptune's mass or less have not hitherto been detected at separations of more than 0.15 au from normal stars. Here we report the discovery of a 5.5(+5.5)(-2.7) M(o) planetary companion at a separation of 2.6+1.5-0.6 au from a 0.22+0.21-0.11 M(o) M-dwarf star, where M(o) refers to a solar mass. (We propose to name it OGLE-2005-BLG-390Lb, indicating a planetary mass companion to the lens star of the microlensing event.) The mass is lower than that of GJ876d (ref. 5), although the error bars overlap. Our detection suggests that such cool, sub-Neptune-mass planets may be more common than gas giant planets, as predicted by the core accretion theory.

The effects of desensitizing agents on the hydraulic conductance of human dentin in vitro.

The hydrodynamic theory of dentin sensitivity states that a stimulus applied at the orifice of exposed dentinal tubules causes movement of tubular fluid which stimulates nerve receptors. The fluid should obey principles of fluid movement through capillary tubes. Any decrease in the functional radius of the dentinal tubules should greatly reduce the rate of fluid flow, thus reducing dentinal sensitivity. The purpose of this study was to evaluate the ability of agents that have been used previously for clinical dentin desensitization to reduce the rate of fluid flow through dentin in vitro. Dentin discs prepared from extracted human third molars were treated with 50% citric acid to remove debris from tubular orifices. After placing the discs in a split chamber device, the rate at which buffer solution could filter across the dentin under 240 cm of water pressure was measured. The occlusal side of the disc was then treated with an agent thought to desensitize dentin to determine if it reduced fluid flow rate. Discs that had more than a 50% reduction in flow rate were examined by scanning electron microscopy to determine if those agents that decreased fluid flow also partially occluded tubular orifices. This in vitro model provided a useful quantitative method for screening a host of preparations that have been used in the past to decrease dentin sensitivity.