Black Holes and (0,4) SCFTs from Type IIB on K3

We study the central charges and levels of 2d $\mathcal{N}=(0,4)$ superconformal field theories that are dual to four- and five-dimensional BPS black holes in compactifications of type IIB string theory on a K3 surface. They arise from wrapping a D3-brane on a curve $C$ inside K3 and have transverse space either an ALE or ALF space. These D3-branes have an AdS$_3 \times \mathrm{S}^3/ \Gamma$ near horizon geometry where $\Gamma$ is a discrete subgroup of $SU(2)$. We compute the central charges and levels of the 2d SCFTs both in the microscopic picture and from six-dimensional $\mathcal{N}=(2,0)$ supergravity. These quantities determine the black hole entropy via Cardy's formula. We find agreement between the microscopic and macroscopic computations. The contributions from one-loop quantum corrections to the macroscopic result are crucial for this matching.Comment: 36 pages; v2: published version, footnotes added, minor typos correcte

The High Energy Telescope on EXIST

The Energetic X-ray Imaging Survey Telescope (EXIST) is a proposed next generation multi-wavelength survey mission. The primary instrument is a High Energy telescope (HET) that conducts the deepest survey for Gamma-ray Bursts (GRBs), obscured-accreting and dormant Supermassive Black Holes and Transients of all varieties for immediate followup studies by the two secondary instruments: a Soft X-ray Imager (SXI) and an Optical/Infrared Telescope (IRT). EXIST will explore the early Universe using high redshift GRBs as cosmic probes and survey black holes on all scales. The HET is a coded aperture telescope employing a large array of imaging CZT detectors (4.5 m^2, 0.6 mm pixel) and a hybrid Tungsten mask. We review the current HET concept which follows an intensive design revision by the HET imaging working group and the recent engineering studies in the Instrument and Mission Design Lab at the Goddard Space Flight Center. The HET will locate GRBs and transients quickly (<10-30 sec) and accurately (< 20") for rapid (< 1-3 min) onboard followup soft X-ray and optical/IR (0.3-2.2 micron) imaging and spectroscopy. The broad energy band (5-600 keV) and the wide field of view (~90 deg x 70 deg at 10% coding fraction) are optimal for capturing GRBs, obscured AGNs and rare transients. The continuous scan of the entire sky every 3 hours will establish a finely-sampled long-term history of many X-ray sources, opening up new possibilities for variability studies.Comment: 10 pages, 6 figures, 3 tables, SPIE conference proceedings (UV, X-ray, and Gamma-Ray Space Instrumentation for Astronomy XVI, 7435-9

Tablet-based strength-balance training to motivate and improve adherence to exercise in independently living older people: Part 2 of a phase ii preclinical exploratory trial

Home-based exercise programs can improve physical functioning and health status of elderly people. Successful implementation of exercise interventions for older people presents major challenges and supporting elderly people properly while doing their home-based exercises is essential for training success. We developed a tablet-based system-ActiveLifestyle-that offers older adults a home-based strength-balance training program with incorporated motivation strategies and support features. Objective: The goal was to compare 3 different home-based training programs with respect to their effect on measures of gait quality and physical performance through planned comparisons between (1) tablet-based and brochure-based interventions, (2) individual and social motivation strategies, and (3) active and inactive participants. Methods: A total of 44 autonomous-living elderly people (mean 75, SD 6 years) were assigned to 3 training groups: social (tablet guided, n=14), individual (tablet guided, n=13), and brochure (brochure guided, n=17). All groups joined a 12-week progressive home-based strength-balance training program. Outcome measures were gait performance under single and dual task conditions, dual task costs of walking, falls efficacy, and physical performance as measured by the Short Physical Performance Battery (SPPB). Furthermore, active (≥75% program compliance) and inactive (<75% program compliance) individuals were compared based on their characteristics and outcome measures. Results: The tablet groups showed significant improvements in single and dual task walking, whereas there were no significant changes observable in the brochure group. Between-groups comparisons revealed significant differences for gait velocity (U=138.5; P=.03, r=.33) and cadence (U=138.5, P=.03 r=.34) during dual task walking at preferred speed in favor of the tablet groups. The brochure group had more inactive participants, but this did not reach statistical significance (U=167, P=.06, r=.29). The active participants outperformed the inactive participants in single and dual task walking, dual task costs of walking, and SPPB scores. Significant between-groups differences were seen between the tablet groups and the brochure group, in favor of the tablet groups. Conclusions: A tablet-based strength-balance training program that allows monitoring and assisting autonomous-living older adults while training at home was more effective in improving gait and physical performance when compared to a brochure-based program. Social or individual motivation strategies were equally effective. The most prominent differences were observed between active and inactive participants. These findings suggest that in older adults a tablet-based intervention enhances training compliance; hence, it is an effective way to improve gait

The Proposed High Energy Telescope (HET) for EXIST

The hard X-ray sky now being studied by INTEGRAL and Swift and soon by NuSTAR is rich with energetic phenomena and highly variable non-thermal phenomena on a broad range of timescales. The High Energy Telescope (HET) on the proposed Energetic X-ray Imaging Survey Telescope (EXIST) mission will repeatedly survey the full sky for rare and luminous hard X-ray phenomena at unprecedented sensitivities. It will detect and localize (<20", at 5 sigma threshold) X-ray sources quickly for immediate followup identification by two other onboard telescopes - the Soft X-ray imager (SXI) and Optical/Infrared Telescope (IRT). The large array (4.5 m^2) of imaging (0.6 mm pixel) CZT detectors in the HET, a coded-aperture telescope, will provide unprecedented high sensitivity (~0.06 mCrab Full Sky in a 2 year continuous scanning survey) in the 5 - 600 keV band. The large field of view (90 deg x 70 deg) and zenith scanning with alternating-orbital nodding motion planned for the first 2 years of the mission will enable nearly continuous monitoring of the full sky. A 3y followup pointed mission phase provides deep UV-Optical-IR-Soft X-ray and Hard X-ray imaging and spectroscopy for thousands of sources discovered in the Survey. We review the HET design concept and report the recent progress of the CZT detector development, which is underway through a series of balloon-borne wide-field hard X-ray telescope experiments, ProtoEXIST. We carried out a successful flight of the first generation of fine pixel large area CZT detectors (ProtoEXIST1) on Oct 9, 2009. We also summarize our future plan (ProtoEXIST2 & 3) for the technology development needed for the HET.Comment: 10 pages, 13 figures, 2 tables, SPIE Conference "Astronomical Telescopes and Instrumentation 2010"; to appear in Proceedings SPIE (2010

Daily life stress and the cortisol awakening response : testing the anticipation hypothesis

Acknowledgments We thank Paul Stewart for his contribution to data collection and Dr Matthew Jones for programming the handheld computers. Author Contributions Conceived and designed the experiments: WS DJP. Performed the experiments: DJP. Analyzed the data: WS. Wrote the paper: WS DJP.Peer reviewedPublisher PD