Orbital migration and the brown dwarf desert

The orbital elements of extreme mass ratio binaries will be modified by interactions with surrounding circumstellar disks. For brown dwarf companions to Solar-type stars the resulting orbital migration is sufficient to drive short period systems to merger, creating a brown dwarf desert at small separations. We highlight the similarities and the differences between the migration of brown dwarfs and massive extrasolar planets, and discuss how observations can test a migration model for the brown dwarf desert.Comment: Proceedings, IAU Symp. 211 on "Brown Dwarfs", ed. E. L. Marti

New Proteins Found Interacting with Brain Metallothionein-3 Are Linked to Secretion

Metallothionein 3 (MT-3), also known as growth inhibitory factor (GIF), exhibits a neuroinhibitory activity. Our lab and others have previously shown that this biological activity involves interacting protein partners in the brain. However, nothing specific is yet known about which of these interactions is responsible for the GIF activity. In this paper, we are reporting upon new proteins found interacting with MT-3 as determined through immunoaffinity chromatography and mass spectrometry. These new partner proteins—Exo84p, 14-3-3 Zeta, α and β Enolase, Aldolase C, Malate dehydrogenase, ATP synthase, and Pyruvate kinase—along with those previously identified have now been classified into three functional groups: transport and signaling, chaperoning and scaffolding, and glycolytic metabolism. When viewed together, these interactions support a proposed model for the regulation of the GIF activity of MT-3

The brown dwarf desert as a consequence of orbital migration

We show that the dearth of brown dwarfs in short-period orbits around Solar-mass stars - the brown dwarf desert - can be understood as a consequence of inward migration within an evolving protoplanetary disc. Brown dwarf secondaries forming at the same time as the primary star have masses which are comparable to the initial mass of the protoplanetary disc. Subsequent disc evolution leads to inward migration, and destruction of the brown dwarf, via merger with the star. This is in contrast with massive planets, which avoid this fate by forming at a later epoch when the disc is close to being dispersed. Within this model, a brown dwarf desert arises because the mass at the hydrogen burning limit is coincidentally comparable to the initial disc mass for a Solar mass star. Brown dwarfs should be found in close binaries around very low mass stars, around other brown dwarfs, and around Solar-type stars during the earliest phases of star formation.Comment: MNRAS (Letters), in pres

Evaluating the PRASE patient safety intervention - a multi-centre, cluster trial with a qualitative process evaluation: study protocol for a randomised controlled trial

Background: Estimates show that as many as one in 10 patients are harmed while receiving hospital care. Previous strategies to improve safety have focused on developing incident reporting systems and changing systems of care and professional behaviour, with little involvement of patients. The need to engage with patients about the quality and safety of their care has never been more evident with recent high profile reviews of poor hospital care all emphasising the need to develop and support better systems for capturing and responding to the patient perspective on their care. Over the past 3 years, our research team have developed, tested and refined the PRASE (Patient Reporting and Action for a Safe Environment) intervention, which gains patient feedback about quality and safety on hospital wards. Methods/design: A multi-centre, cluster, wait list design, randomised controlled trial with an embedded qualitative process evaluation. The aim is to assess the efficacy of the PRASE intervention, in achieving patient safety improvements over a 12-month period. The trial will take place across 32 hospital wards in three NHS Hospital Trusts in the North of England. The PRASE intervention comprises two tools: (1) a 44-item questionnaire which asks patients about safety concerns and issues; and (2) a proforma for patients to report (a) any specific patient safety incidents they have been involved in or witnessed and (b) any positive experiences. These two tools then provide data which are fed back to wards in a structured feedback report. Using this report, ward staff are asked to hold action planning meetings (APMs) in order to action plan, then implement their plans in line with the issues raised by patients in order to improve patient safety and the patient experience. The trial will be subjected to a rigorous qualitative process evaluation which will enable interpretation of the trial results. Methods: fieldworker diaries, ethnographic observation of APMs, structured interviews with APM lead and collection of key data about intervention wards. Intervention fidelity will be assessed primarily by adherence to the intervention via scoring based on an adapted framework. Discussion: This study will be one of the largest patient safety trials ever conducted, involving 32 hospital wards. The results will further understanding about how patient feedback on the safety of care can be used to improve safety at a ward level. Incorporating the ‘patient voice’ is critical if patient feedback is to be situated as an integral part of patient safety improvements

Relationships between brain and body temperature, clinical and imaging outcomes after ischemic stroke

Pyrexia soon after stroke is associated with severe stroke and poor functional outcome. Few studies have assessed brain temperature after stroke in patients, so little is known of its associations with body temperature, stroke severity, or outcome. We measured temperatures in ischemic and normal-appearing brain using (1)H-magnetic resonance spectroscopy and its correlations with body (tympanic) temperature measured four-hourly, infarct growth by 5 days, early neurologic (National Institute of Health Stroke Scale, NIHSS) and late functional outcome (death or dependency). Among 40 patients (mean age 73 years, median NIHSS 7, imaged at median 17 hours), temperature in ischemic brain was higher than in normal-appearing brain on admission (38.6°C-core, 37.9°C-contralateral hemisphere, P=0.03) but both were equally elevated by 5 days; both were higher than tympanic temperature. Ischemic lesion temperature was not associated with NIHSS or 3-month functional outcome; in contrast, higher contralateral normal-appearing brain temperature was associated with worse NIHSS, infarct expansion and poor functional outcome, similar to associations for tympanic temperature. We conclude that brain temperature is higher than body temperature; that elevated temperature in ischemic brain reflects a local tissue response to ischemia, whereas pyrexia reflects the systemic response to stroke, occurs later, and is associated with adverse outcomes

Study protocol for statin web-based investigation of side effects (StatinWISE):a series of randomised controlled N-of-1 trials comparing atorvastatin and placebo in UK primary care

Introduction: Statins are effective at preventing cardiovascular disease, widely prescribed, and their use is growing. Uncertainty persists about whether they cause symptomatic muscle adverse effects, such as pain and weakness, in the absence of statin myopathy. Discrepancies between data from observational studies, which suggest statins are associated with excess muscle symptoms, and from randomised trials, which suggest no such excess, have caused confusion. N-of-1 trials offer the opportunity to establish whether muscle symptoms during statin use are caused by statins in particular individuals. Methods and analysis: This series of 200 randomised, double blinded N-of-1 trials in primary care will determine (i) the effect of statins on all muscle symptoms, and (ii) the effect of statins on muscle pain that is perceived to be statin related. Patients who are considering discontinuing statin use due to muscle symptoms, and those who have discontinued in the last three years due to such symptoms, will be recruited. Participants will be randomised to a sequence of six two-month treatment periods during which they will receive atorvastatin 20mg daily or matched placebo. On each of the last seven days of each treatment period, participants will rate their muscle symptoms on a Visual Analogue Scale (VAS). At the end of their trial, participants will be shown numerical and graphical summaries of their own symptom data during statin and placebo periods. The primary analysis on the aggregate data from all participants will be a linear mixed model for VAS muscle symptom score, comparing scores during treatment with statin and placebo. Ethics and dissemination: This trial received a favourable opinion from South Central - Hampshire A Research Ethics Committee. Results will be published in a peer-reviewed medical journal. Dissemination of results to patients will take place via the media, website (statinwise.lshtm.ac.uk) and patient organisations