An observational test of common-envelope evolution

By analysing and modelling the change in the abundance ratio of $^{12}$C/$^{13}$C and $^{16}$O/$^{17}$O on the surface of the lower mass star of a binary during the common-envelope (CE) phase of evolution, we propose a simple observational test of the CE scenario. The test is based on the infrared measurement of either the $^{12}$C/$^{13}$C or $^{16}$O/$^{17}$O ratio of red dwarfs in post-common envelope binaries (PCEB's). In certain cases (main-sequence red dwarf secondaries in PCEB's without planetary nebulae), as well as determining whether or not accretion has occurred during the CE phase, we can determine the amount of mass accreted during the CE phase and hence the initial mass of the red dwarf component prior to the CE phase. In the other cases considered (low-mass red dwarfs in PCEB's and red dwarf's in PCEB's with planetary nebulae) we can only say whether or not accretion has occurred during the CE phase.Comment: uuencoded compressed postscript. The preprint are also available at URL http://www.ast.cam.ac.uk/preprint/PrePrint.htm

Using binary statistics in Taurus-Auriga to distinguish between brown dwarf formation processes

Whether BDs form as stars through gravitational collapse ("star-like") or BDs and some very low-mass stars constitute a separate population which form alongside stars comparable to the population of planets, e.g. through circumstellar disk ("peripheral") fragmentation, is one of the key questions of the star-formation problem. For young stars in Taurus-Auriga the binary fraction is large with little dependence on primary mass above ~0.2Msun, while for BDs it is <10%. We investigate a case in which BDs in Taurus formed dominantly through peripheral fragmentation. The decline of the binary frequency in the transition region between star-like and peripheral formation is modelled. A dynamical population synthesis model is employed in which stellar binary formation is universal. Peripheral objects form separately in circumstellar disks with a distinctive initial mass function (IMF), own orbital parameter distributions for binaries and a low binary fraction. A small amount of dynamical processing of the stellar component is accounted for as appropriate for the low-density Taurus-Auriga embedded clusters. The binary fraction declines strongly between the mass-limits for star-like and peripheral formation. The location of characteristic features and the steepness depend on these mass-limits. Such a trend might be unique to low density regions hosting dynamically unprocessed binary populations. The existence of a strong decline in the binary fraction -- primary mass diagram will become verifiable in future surveys on BD and VLMS binarity in the Taurus-Auriga star forming region. It is a test of the (non-)continuity of star formation along the mass-scale, the separateness of the stellar and BD populations and the dominant formation channel for BDs and BD binaries in regions of low stellar density hosting dynamically unprocessed populations.Comment: accepted for publication in A&A, 11 pages, 4 figures, 1 tabl

Image-based Quantification of 3D Morphology for Bifurcations in the Left Coronary Artery: Application to Stent Design

Background Improved strategies for stent‐based treatment of coronary artery disease at bifurcations require a greater understanding of artery morphology. Objective We developed a workflow to quantify morphology in the left main coronary (LMCA), left anterior descending (LAD), and left circumflex (LCX) artery bifurcations. Methods Computational models of each bifurcation were created for 55 patients using computed tomography images in 3D segmentation software. Metrics including cross‐sectional area, length, eccentricity, taper, curvature, planarity, branching law parameters, and bifurcation angles were assessed using open‐sources software and custom applications. Geometric characterization was performed by comparison of means, correlation, and linear discriminant analysis (LDA). Results Differences between metrics suggest dedicated or multistent approaches should be tailored for each bifurcation. For example, the side branch of the LCX (i.e., obtuse marginal; OM) was longer than that of the LMCA (i.e., LCXprox) and LAD (i.e., first diagonal; D1). Bifurcation metrics for some locations (e.g., LMCA Finet ratio) provide results and confidence intervals agreeing with prior findings, while revised metric values are presented for others (e.g., LAD and LCX). LDA revealed several metrics that differentiate between artery locations (e.g., LMCA vs. D1, LMCA vs. OM, LADprox vs. D1, and LCXprox vs. D1). Conclusions These results provide a foundation for elucidating common parameters from healthy coronary arteries and could be leveraged in the future for treating diseased arteries. Collectively the current results may ultimately be used for design iterations that improve outcomes following implantation of future dedicated bifurcation stents

Hidden persuaders on film: Exploring young people’s lived experience through visual essays

The Hidden Persuaders research group examines ‘brainwashing’ in the Cold War for the roles, real and imagined, played by psychologists, psychiatrists and psychoanalysts. Our project engaged young people in an exploration of the history of fears about brainwashing, and enabled them to explore their thoughts and ideas about the forces that shape their lives in contemporary society, through film-making. Working with three schools in the Camden area of London, our partners at the Derek Jarman Lab media hub, Birkbeck, University of London, and an artist facilitator (Lizzie Burns), we invited Year 12 students to learn filming and editing to create their own short video essays. The use of this format resulted in a significant depth of engagement and generated a wealth of creative responses. The various stages of the film-making process enabled the students to work out the terms of an argument and to consider how best to express it concisely. In the resulting films, they came up with a variety of forms of visual storytelling, and used the medium to express their thoughts, feelings and ideas in diverse ways, giving us a range of new perspectives which we could consider in relation to our historical research

Peer support for discharge from inpatient to community mental health services: Study protocol clinical trial (SPIRIT Compliant).

INTRODUCTION: In the period shortly after discharge from inpatient to community mental health care, people are at increased risk of self-harm, suicide, and readmission to hospital. Discharge interventions including peer support have shown potential, and there is some evidence that community-based peer support reduces readmissions. However, systematic reviews of peer support in mental health services indicate poor trial quality and a lack of reporting of how peer support is distinctive from other mental health support. This study is designed to establish the clinical and cost effectiveness of a peer worker intervention to support discharge from inpatient to community mental health care, and to address issues of trial quality and clarity of reporting of peer support interventions. METHODS: This protocol describes an individually randomized controlled superiority trial, hypothesizing that people offered a peer worker discharge intervention in addition to usual follow-up care in the community are less likely to be readmitted in the 12 months post discharge than people receiving usual care alone. A total of 590 people will be recruited shortly before discharge from hospital and randomly allocated to care as usual plus the peer worker intervention or care as usual alone. Manualized peer support provided by trained peer workers begins in hospital and continues for 4 months in the community post discharge. Secondary psychosocial outcomes are assessed at 4 months post discharge, and service use and cost outcomes at 12 months post discharge, alongside a mixed methods process evaluation. DISCUSSION: Clearly specified procedures for sequencing participant allocation and for blinding assessors to allocation, plus full reporting of outcomes, should reduce risk of bias in trial findings and contribute to improved quality in the peer support evidence base. The involvement of members of the study team with direct experience of peer support, mental distress, and using mental health services, in coproducing the intervention and designing the trial, ensures that we theorize and clearly describe the peer worker intervention, and evaluate how peer support is related to any change in outcome. This is an important methodological contribution to the evidence base. TRIAL REGISTRATION: This study was prospectively registered as ISRCTN 10043328 on November 28, 2016