Off-Beam Gamma-Ray Pulsars and Unidentified EGRET Sources in the Gould Belt

We investigate whether gamma-ray pulsars viewed at a large angle to the neutron star magnetic pole could contribute to the new population of galactic unidentified EGRET sources associated with the Gould Belt. The faint, soft nature of these sources is distinctly different from both the properties of unidentified EGRET sources along the galactic plane and of the known gamma-ray pulsars. We explore the possibility, within the polar cap model, that some of these sources are emission from pulsars seen at lines of sight that miss both the bright gamma-ray cone beams and the radio beam. The off-beam gamma-rays come from high-altitude curvature emission of primary particles, are radiated over a large solid angle and have a much softer spectrum than that of the main beams. We estimate that the detectability of such off-beam emission is about a factor of 4-5 higher than that of the on-beam emission. At least some of the radio-quiet Gould Belt sources detected by EGRET could therefore be such off-beam gamma-ray pulsars. GLAST should be able to detect pulsations in most of these sources.Comment: 5 pages, uses emulateapj.sty, accepted for publication in ApJ Letter

Developing a suicide prevention programme to address the increase in prison suicides in Kent

This document presents the final report of a student internship project, focusing on the development of a suicide prevention programme in Kent. Following an increase in prison suicides between 2013 and 2014, Kent & Medway Suicide Prevention Steering Group were approached by the commissioning manager for health and justice to conduct research into this area. Dr Ian Marsh from Canterbury Christ Church University put forward the CCCU student internship as a means of undertaking this research. The Research and Knowledge Exchange internships at Canterbury Christ Church University allow students to work with academic staff on a specific research project. Academics apply for a research intern to work with them on research in areas which are likely to result in tangible outputs. The author of this report is a final year BSc Sociology student at Canterbury Christ Church University who worked as an intern on this project for a period of 10 weeks from May to July. The project involved an extensive literature review, along with consultation with various agencies and individuals, in order to gain a deeper insight into the emerging issues. Consultations were with the following stakeholders: • Kent and Medway Suicide Prevention Steering Group • Mental health in-reach team at HMP Elmley • The Samaritans Listener Scheme Co-ordinator • The Howard League Policy Officer • The Prisons and Probation Assistant Ombudsman • Safer Custody team for Kent This report provides a brief overview of suicides, prison suicides, and prevention - nationally and in Kent. Key themes from the literature are outlined and supported with insight from the consultations where appropriate. Recommendations are put forward where appropriate in regard to potential steps for prison suicide prevention in Kent. Project Aims The main aims of this project were to: • Review existing literature and data around prison suicides and prevention. • Meet with key stakeholders who could give a deeper insight into these issues. • Present findings to the Kent & Medway suicide prevention steering group. • Use the final report to inform relevant agencies and prison staff

Young and middle age pulsar light-curve morphology: Comparison of Fermi observations with gamma-ray and radio emission geometries

Thanks to the huge amount of gamma-ray pulsar photons collected by the Fermi Large Area Telescope since June 2008, it is now possible to constrain gamma-ray geometrical models by comparing simulated and observed light-curve morphological characteristics. We assumed vacuum-retarded dipole pulsar magnetic field and tested simulated and observed morphological light-curve characteristics in the framework of two pole emission geometries, Polar Cap (PC), radio, and Slot Gap (SG), and Outer Gap (OG)/One Pole Caustic (OPC) emission geometries. We compared simulated and observed/estimated light-curve morphological parameters as a function of observable and non-observable pulsar parameters. The PC model gives the poorest description of the LAT pulsar light-curve morphology. The OPC best explains both the observed gamma-ray peak multiplicity and shape classes. The OPC and SG models describe the observed gamma-ray peak-separation distribution for low- and high-peak separations, respectively. This suggests that the OPC geometry best explains the single-peak structure but does not manage to describe the widely separated peaks predicted in the framework of the SG model as the emission from the two magnetic hemispheres. The OPC radio-lag distribution shows higher agreement with observations suggesting that assuming polar radio emission, the gamma-ray emission regions are likely to be located in the outer magnetosphere. The larger agreement between simulated and LAT estimations in the framework of the OPC suggests that the OPC model best predicts the observed variety of profile shapes. The larger agreement between observations and the OPC model jointly with the need to explain the abundant 0.5 separated peaks with two-pole emission geometries, calls for thin OPC gaps to explain the single-peak geometry but highlights the need of two-pole caustic emission geometry to explain widely separated peaks.Comment: 28 pages, 20 figures, 8 tables; accepted for publication in Astronomy and Astrophysic

Blood-Brain Barrier-on-a-chip Systems Based on 3D Printing

This research focused on the design and testing of a blood-brain barrier (BBB)-on-a-chip microfluidic device produced using 3D printing. First, COMSOL simulations were used to define dimensions of the microchannel that would most accurately replicate the flow environment imposed on the blood-brain barrier, the wall shear stress being the most important characteristic. In using COMSOL, water was used as the simulated fluid and also the testing fluid in the fabricated devices. Therefore, the microsystem is designed to produce the BBB environment using water instead of blood. The numerical simulation parameters were based on theoretical calculations performed to scale up the dimensions of the brain capillary with the BBB to the dimensions of a microchannel that is possible to 3D print. The COMSOL simulation results show that a rectangular channel with a height of 2 mm and width of 0.5 mm will be under a wall shear stress of approximately 0.43 Pa at 2500 μL/min, 0.75 Pa at 4000μL/min, and 1.99 Pa at 9000 μL/min. A micropump designed and tested by Carlton McMullen is used as the standard for new models, which are fabricated using a MakerBot Replicator 2 3D printer [11]. Its pumping capabilities were tested to determine if it could produce the flow rates found in the numerical simulations. The pump was tested at actuation pressures of 20 psi, 30 psi, and 40 psi, while the actuation frequency was held constant at 10 Hz. The average flow rate was 2810 μL/min at 20 psi, 3420 μL/min at 30 psi, and 5325 μL/min at 40 psi. These results indicate that the current micropump could cause a wall shear stress up to 0.87 Pa in the microchannel where the BBB is replicated and studied. This value is within the range of in vivo shear stress values, validating this method of using water to recreate the environment. With these flow rate results, the micropump design is capable of producing flow rates required for in vivo shear stress values. This research defines 3D printable microchannel dimensions that allow these shear stress values based on attainable flow rates from this micropump

The role of reconnection in the pulsar magnetosphere

The present work is our first attempt to understand the role of reconnection in the pulsar magnetosphere. Our discussion is based on the observationaly infered fact that, as the pulsar spins down, the region of closed corotating dipolar field lines grows with time. This implies that reconnection must take place in the magnetosphere. We argue that non-dissipative reconnection along the equatorial current sheet allows for the continuous channeling of pulsar spindown energy into particle energy, all the way from the light cylinder to the pulsar wind termination shock, and we propose that this effect may account for the low \sigma values inferred by observations. We present a simple model that allows us to relate the magnetic diffusivity in the equatorial current sheet to an observable pulsar parameter, the braking index n. When n~1, the global structure of the magnetosphere approaches that of a relativistic split monopole where the pulsar spindown energy is carried by the electromagnetic field. However, for values of n>1.5, almost all field lines close inside the pulsar wind termination shock, and thus most of the electromagnetic pulsar spindown energy flux is effectively transformed into particle energy in the equatorial current sheet

Strategies to improve retention in randomised trials: a Cochrane systematic review and meta-analysis

Objective: To quantify the effect of strategies to improve retention in randomised trials.<p></p> Design: Systematic review and meta-analysis.<p></p> Data sources Sources searched: MEDLINE, EMBASE, PsycINFO, DARE, CENTRAL, CINAHL, C2-SPECTR, ERIC, PreMEDLINE, Cochrane Methodology Register, Current Controlled Trials metaRegister, WHO trials platform, Society for Clinical Trials (SCT) conference proceedings and a survey of all UK clinical trial research units.<p></p> Review: methods Included trials were randomised evaluations of strategies to improve retention embedded within host randomised trials. The primary outcome was retention of trial participants. Data from trials were pooled using the fixed-effect model. Subgroup analyses were used to explore the heterogeneity and to determine whether there were any differences in effect by the type of strategy.<p></p> Results: 38 retention trials were identified. Six broad types of strategies were evaluated. Strategies that increased postal questionnaire responses were: adding, that is, giving a monetary incentive (RR 1.18; 95% CI 1.09 to 1.28) and higher valued incentives (RR 1.12; 95% CI 1.04 to 1.22). Offering a monetary incentive, that is, an incentive given on receipt of a completed questionnaire, also increased electronic questionnaire response (RR 1.25; 95% CI 1.14 to 1.38). The evidence for shorter questionnaires (RR 1.04; 95% CI 1.00 to 1.08) and questionnaires relevant to the disease/condition (RR 1.07; 95% CI 1.01 to 1.14) is less clear. On the basis of the results of single trials, the following strategies appeared effective at increasing questionnaire response: recorded delivery of questionnaires (RR 2.08; 95% CI 1.11 to 3.87); a ‘package’ of postal communication strategies (RR 1.43; 95% CI 1.22 to 1.67) and an open trial design (RR 1.37; 95% CI 1.16 to 1.63). There is no good evidence that the following strategies impact on trial response/retention: adding a non-monetary incentive (RR=1.00; 95% CI 0.98 to 1.02); offering a non-monetary incentive (RR=0.99; 95% CI 0.95 to 1.03); ‘enhanced’ letters (RR=1.01; 95% CI 0.97 to 1.05); monetary incentives compared with offering prize draw entry (RR=1.04; 95% CI 0.91 to 1.19); priority postal delivery (RR=1.02; 95% CI 0.95 to 1.09); behavioural motivational strategies (RR=1.08; 95% CI 0.93 to 1.24); additional reminders to participants (RR=1.03; 95% CI 0.99 to 1.06) and questionnaire question order (RR=1.00, 0.97 to 1.02). Also based on single trials, these strategies do not appear effective: a telephone survey compared with a monetary incentive plus questionnaire (RR=1.08; 95% CI 0.94 to 1.24); offering a charity donation (RR=1.02, 95% CI 0.78 to 1.32); sending sites reminders (RR=0.96; 95% CI 0.83 to 1.11); sending questionnaires early (RR=1.10; 95% CI 0.96 to 1.26); longer and clearer questionnaires (RR=1.01, 0.95 to 1.07) and participant case management by trial assistants (RR=1.00; 95% CI 0.97 to 1.04).<p></p> Conclusions: Most of the trials evaluated questionnaire response rather than ways to improve participants return to site for follow-up. Monetary incentives and offers of monetary incentives increase postal and electronic questionnaire response. Some strategies need further evaluation. Application of these results would depend on trial context and follow-up procedures.<p></p&gt