High Energy Neutrinos and Photons from Curvature Pions in Magnetars

We discuss the relevance of the curvature radiation of pions in strongly magnetized pulsars or magnetars, and their implications for the production of TeV energy neutrinos detectable by cubic kilometer scale detectors, as well as high energy photons.Comment: 19 pages, 4 figures, to appear in JCA

Self-consistent models for Coulomb heated X-ray pulsar atmospheres

Calculations of accreting magnetized neutron star atmospheres heated by the gradual deceleration of protons via Coulomb collisions are presented. Self consistent determinations of the temperature and density structure for different accretion rates are made by assuming hydrostatic equilibrium and energy balance, coupled with radiative transfer. The full radiative transfer in two polarizations, using magnetic cross sections but with cyclotron resonance effects treated approximately, is carried out in the inhomogeneous atmospheres

The Multi-Component Nature of the Vela Pulsar Nonthermal X-ray Spectrum

We report on our analysis of a 274 ks observation of the Vela pulsar with the Rossi X-Ray Timing Explorer (RXTE). The double-peaked, pulsed emission at 2 - 30 keV, which we had previously detected during a 93 ks observation, is confirmed with much improved statistics. There is now clear evidence, both in the spectrum and the light curve, that the emission in the RXTE band is a blend of two separate non-thermal components. The spectrum of the harder component connects smoothly with the OSSE, COMPTEL and EGRET spectrum and the peaks in the light curve are in phase coincidence with those of the high-energy light curve. The spectrum of the softer component is consistent with an extrapolation to the pulsed optical flux, and the second RXTE pulse is in phase coincidence with the second optical peak. In addition, we see a peak in the 2-8 keV RXTE pulse profile at the radio phase.Comment: 12 pages, 3 figures, accepted for publication in Astrophysical Journa

Using psychological and physiological measures in arts-based activities in a community sample of people with a dementia and their caregivers: a feasibility and pilot study

Introduction: Nearly all community-based dementia care studies employ either qualitative methods or use a combination of self-report questionnaire within mixed-methods research designs. Physiological measures, however, are rarely used in community-based studies with this population yet could provide valuable biological information for specific activities across the course of the dementias. Method: The study employed a within-subjects design to assess the feasibility of obtaining physiological measures (salivary cortisol and Heart Rate Variability (HRV)) alongside subjective measures of wellbeing and stress using Visual Analogue Scales (VAS) during two community-based activiti of choral singing and art viewing, respectively, for People With Dementia (PWD) in the early to middle stages of impairment and their caregivers. Results: As anticipated, pre-post subjective wellbeing measures were relatively easy to complete by PWD and caregivers with no substantive difficulties observed or reported; significant increases in composite wellbeing, happiness and optimism were found. Continuous measurement of physiological data of HRV through a sensor-based device (Empatica® E4) was also found to be neither non-intrusive to participants nor disruptive to the interventions. Preliminary indications showed, for example, HRV significantly increased for PWD during choral singing, which may be associated with an increase in wellbeing. Measuring stress hormones through pre-post saliva samples, however, encountered several difficulties. Conclusions: The findings provide support for the feasibility of using non-intrusive sensor-based physiological measures alongside subjective measures for this population. Subjective measures may also give more confidence in interpreting directionality of physiological measures. A full pilot study is warranted to further investigate interactions of physiological and psychological variables in choral singing and viewing art activities but it is uncertain whether measuring stress hormones through saliva collection is feasible for this population and raised doubts about their use in a large scale trial. Holding particular promise is the use of sensor-based technology across different stages of dementia as well as across different activities

Use of strategies to improve retention in primary care randomised trials: a qualitative study with in-depth interviews

Objective To explore the strategies used to improve retention in primary care randomised trials.<p></p> Design Qualitative in-depth interviews and thematic analysis.<p></p> Participants 29 UK primary care chief and principal investigators, trial managers and research nurses.<p></p> Methods In-depth face-to-face interviews.<p></p> Results Primary care researchers use incentive and communication strategies to improve retention in trials, but were unsure of their effect. Small monetary incentives were used to increase response to postal questionnaires. Non-monetary incentives were used although there was scepticism about the impact of these on retention. Nurses routinely used telephone communication to encourage participants to return for trial follow-up. Trial managers used first class post, shorter questionnaires and improved questionnaire designs with the aim of improving questionnaire response. Interviewees thought an open trial design could lead to biased results and were negative about using behavioural strategies to improve retention. There was consensus among the interviewees that effective communication and rapport with participants, participant altruism, respect for participant's time, flexibility of trial personnel and appointment schedules and trial information improve retention. Interviewees noted particular challenges with retention in mental health trials and those involving teenagers.<p></p> Conclusions The findings of this qualitative study have allowed us to reflect on research practice around retention and highlight a gap between such practice and current evidence. Interviewees describe acting from experience without evidence from the literature, which supports the use of small monetary incentives to improve the questionnaire response. No such evidence exists for non-monetary incentives or first class post, use of which may need reconsideration. An exploration of barriers and facilitators to retention in other research contexts may be justified.<p></p&gt

The Contribution of Blazars to the Extragalactic Diffuse Gamma-ray Background and Their Future Spatial Resolution

We examine the constraints on the luminosity-dependent density evolution model for the evolution of blazars given the observed spectrum of the diffuse gamma-ray background (DGRB), blazar source-count distribution, and the blazar spectral energy distribution sequence model, which relates the observed the blazar spectrum to its luminosity. We show that the DGRB observed by the Large Area Telescope (LAT) aboard the Fermi Gamma Ray Space Telescope can be produced entirely by gamma-ray emission from blazars and nonblazar active galactic nuclei, and that our blazar evolution model is consistent with and constrained by the spectrum of the DGRB and flux source-count distribution function of blazars observed by Fermi-LAT. Our results are consistent with previous work that used EGRET spectral data to forecast the Fermi-LAT DGRB. The model includes only three free parameters, and forecasts that >~ 95% of the flux from blazars will be resolved into point sources by Fermi-LAT with 5 years of observation, with a corresponding reduction of the flux in the DGRB by a factor of ~2 to 3 (95% confidence level), which has implications for the Fermi-LAT's sensitivity to dark matter annihilation photons.Comment: 13 pages, 7 figures; v3: minor changes, matches version to appear in Phys. Rev.