Magnetically modulated accretion in T Tauri stars

We examine how accretion on to T Tauri stars may be modulated by a time-dependent `magnetic gate' where the inner edge of the accretion disc is disrupted by a varying stellar field. We show that magnetic field variations on time-scales shorter than 10^5 yr can modulate the accretion flow, thus providing a possible mechanism both for the marked photometric variability of T Tauri stars and for the possible conversion of T Tauri stars between classical and weak line status. We thus suggest that archival data relating to the spectrophotometric variability of T Tauri stars may provide an indirect record of magnetic activity cycles in low-mass pre-main-sequence stars.Comment: LaTeX file (requires mn.sty), 4 pages, no figures or tables. To appear in MNRAS

Evaluation of the ECOSSE model to predict heterotrophic soil respiration by direct measurements

Acknowledgements This work contributes to the ELUM (Ecosystem Land Use Modelling & Soil Carbon GHG Flux Trial) project, which was commissioned and funded by the Energy Technologies Institute (ETI), and to Carbo-BioCrop (http://www.carbobiocrop.ac.uk; a NERC funded project; NE/H010742/1), UKERC Phase II and III (NERC; NE/H013237/1), MAGLUE (http://www.maglue.ac.uk; an EPSRC funded project; EP/M013200/1) and as part of the Seventh Framework For Research Programme of the EU, within the EUROCHAR project (N 265179) and EXPEER within WU FP7-Infrastructures. We acknowledge the use of the E-OBS dataset from the EU-FP6 project ENSEMBLES (http://ensembles-eu.metoffice.com) and the data providers in the ECA&D project (http://www.ecad.eu). We thank two anonymous reviewers and Dr William van Dijk for their valuable suggestions.Peer reviewedPostprin

Modelling bacterial behaviour close to a no-slip plane boundary: the influence of bacterial geometry

We describe a boundary-element method used to model the hydrodynamics of a bacterium propelled by a single helical flagellum. Using this model, we optimize the power efficiency of swimming with respect to cell body and flagellum geometrical parameters, and find that optima for swimming in unbounded fluid and near a no-slip plane boundary are nearly indistinguishable. We also consider the novel optimization objective of torque efficiency and find a very different optimal shape. Excluding effects such as Brownian motion and electrostatic interactions, it is demonstrated that hydrodynamic forces may trap the bacterium in a stable, circular orbit near the boundary, leading to the empirically observable surface accumulation of bacteria. Furthermore, the details and even the existence of this stable orbit depend on geometrical parameters of the bacterium, as described in this article. These results shed some light on the phenomenon of surface accumulation of micro-organisms and offer hydrodynamic explanations as to why some bacteria may accumulate more readily than others based on morphology

Self-incentives uniquely boost cessation in community-based stop smoking programs: Randomized controlled trial

Background: Self-incentives offer a plausible alternative to paying smokers to quit but have not yet been tested in a randomized controlled trial.  Purpose: The present study tested whether, compared with a control group, prompting smokers explicitly to self-incentivize if they abstain from smoking for a week or a month encouraged sustained abstinence.  Method: One hundred and fifty-nine smokers were recruited from stop smoking clinics and randomized to an active control condition (asked to form a plan to quit, n = 65) or one of two intervention conditions in which they were asked to form implementation intentions designed to ensure that they incentivized themselves if they had not smoked at all by the end of (a) the week (n = 44) or (b) the month (n = 50). The main outcome measure was self-reported abstinence at 3- and 6-month follow-ups, which was biochemically verified at baseline and in a subsample at 3-month follow-up.  Results: At 3-month follow-up, 34% (15/44; p < .05, d = 0.45) and 36% (18/50; p < .05, d = 0.49) of smokers abstained in the weekly and monthly self-incentivizing conditions respectively, compared with 15% (10/65) in the control. The same pattern of findings was observed at 6-month follow-up: 30% (13/44; p < .05, d = 0.35), 34% (17/50; p < .05, d = 0.45) and 15% (10/65) of smokers remained abstinent in the two intervention groups and control group, respectively.  Conclusions: Ensuring that smokers self-incentivized boosted significantly the effectiveness of the stop smoking program. Self-incentivizing implementation intentions could be implemented at low cost with high public health “reach” to change many health behaviors beyond smoking

Doping effect on the anomalous behavior of the Hall effect in electron-doped superconductor Nd2−x_{2-x}Cex_xCuO4+δ_{4+\delta}

Transport properties of Nd$_{2-x}$Ce$_x$CuO$_{4+\delta}$ single crystal films are investigated in magnetic fields $B$ up to 9T at $T$=(0.4-4.2)K. An analysis of normal state (at $B>B_{c2}$) Hall coefficient $R_H$$^n$ dependence on Ce doping takes us to a conclusion about the existence both of electron-like and hole-like contributions to transport in nominally electron-doped system. In accordance with $R_H$$^n$(x) analysis an anomalous sign reversal of Hall effect in mixed state at $B<B_{c2}$ may be ascribed to a flux-flow regime for two types of carriers with opposite charges.Comment: 14 pages, 5 figure

Effective CCTV and the challenge of constructing legitimate suspicion using remote visual images

This paper compares the effectiveness of public CCTV systems according to meta-reviews, with what might be expected based upon theoretical predictions. The apparent gulf between practice and prediction is explored in the light of the challenges faced by CCTV operators in terms of effective target selection. In addition, counter-intuitive reactions by members of the public to situational symbols of crime deterrence may also undermine the efficacy of CCTV. Evidence is introduced and reviewed that suggests CCTV operators may employ implicit profiles to select targets. Essentially, young, scruffy males who appear to be loitering are disproportionately targeted compared with their base rate use of surveyed areas. However, the extent to which such a profile is diagnostic of criminal intent or behaviour is unclear. Such profiles may represent little more than ‘pattern matching’ within an impoverished visual medium. Finally, suggestions for future research and effective CCTV operator practice are offered in order to improve target selection.Peer reviewe

The effects of using examination grade as a primary outcome in education trials to evaluate school-based interventions

This paper aims to assess the impact of using GCSE grades as a primary outcome in educational evaluations and trials, compared to using marks. The choice of grades or marks is relevant as many evaluations use GCSE performance as an outcome measure. For such evaluations, the National Pupil Database (NPD) is used as a source of data by the vast majority, and it contains grade information only; no information on the underlying mark distribution is available. The use of the NPD has largely been a pragmatic choice, as historically it has been comparatively easy to access grades via the NPD than gather marks (or indeed grades) from schools or awarding organisations. However, there has been little consideration of whether only having access to grade information, as opposed to the marks, has consequences for evaluations. This paper seeks to fill this gap in the literature

Medical student‐led simulation in COVID‐19 crisis

Background: Simulation training is an effective tool for improving confidence in healthcare workers. During the recent COVID‐19 pandemic, large numbers of staff required re‐training to manage unfamiliar situations. We present a set of medical student‐led clinical simulation sessions and evaluate their effects on (i) confidence among redeployed healthcare workers managing COVID‐19 patients and (ii) medical students’ confidence as educators. / Methods: Half‐day simulation training sessions consisting of three COVID‐related clinical scenarios were devised by senior medical students and delivered to a group of approximately 150 healthcare workers over six repeated sessions prior to redeployment to COVID‐19 wards. We distributed an anonymous pre‐ and post‐simulation questionnaire to 36 participants in the final group exploring their experiences. The confidence scores were analysed using the Wilcoxon signed‐rank test. Following the delivery of teaching, medical students completed a questionnaire assessing their personal experiences of designing and delivering the exercises. / Results: Data are available for 35/36 participants approached. Respondents reported being significantly more confident after the training in all aspects of managing COVID‐19 patients, including triage, complex discharge, recognising deterioration, initiating basic life support, managing symptoms and advising on visiting policies (p < 0.001); 97% of respondents rated the training as useful. Thematic analysis of medical students’ responses demonstrated mutual benefit. / Discussion: This study demonstrates the strengths of simulation training in helping to build staff confidence in a rapidly evolving situation and highlights the value of medical students in supporting a hospital’s response to an outbreak. We recommend further studies of student‐led simulation exercises, including longer‐term follow‐up