Correlative Spectral Analysis of Gamma-Ray Bursts using Swift-BAT and GLAST-GBM

We discuss the preliminary results of spectral analysis simulations involving anticipated correlated multi-wavelength observations of gamma-ray bursts (GRBs) using Swift's Burst Alert Telescope (BAT) and the Gamma-Ray Large Area Space Telescope's (GLAST) Burst Monitor (GLAST-GBM), resulting in joint spectral fits, including characteristic photon energy (Epeak) values, for a conservative annual estimate of ~30 GRBs. The addition of BAT's spectral response will (i) complement in-orbit calibration efforts of GBM's detector response matrices, (ii) augment GLAST's low energy sensitivity by increasing the ~20-100 keV effective area, (iii) facilitate ground-based follow-up efforts of GLAST GRBs by increasing GBM's source localization precision, and (iv) help identify a subset of non-triggered GRBs discovered via off-line GBM data analysis. Such multi-wavelength correlative analyses, which have been demonstrated by successful joint-spectral fits of Swift-BAT GRBs with other higher energy detectors such as Konus-WIND and Suzaku-WAM, would enable the study of broad-band spectral and temporal evolution of prompt GRB emission over three energy decades, thus potentially increasing the science return without placing additional demands upon mission resources throughout their contemporaneous orbital tenure over the next decade.Comment: 5 pages. Adapted from a contribution to the Proceedings of the 2008 Nanjing GRB Conference. Edited by Y. F. Huang, Z. G. Dai and B. Zhan

Motivating Process Compliance Through Individual Electronic Monitoring: An Empirical Examination of Hand Hygiene in Healthcare

The design and use of standard processes are foundational recommendations in many operations practices. Yet, given the demonstrated performance benefits of standardized processes, it is surprising that they are often not followed consistently. One way to ensure greater compliance is by electronically monitoring the activities of individuals, although such aggressive monitoring poses the risk of inducing backlash. In the setting of hand hygiene in healthcare, a context where compliance with standard processes is frequently less than 50% and where this lack of compliance can result in negative consequences, we investigated the effectiveness of electronic monitoring. We did so using a unique, radio frequency identification (RFID)-based system deployed in 71 hospital units. We found that electronically monitoring individual compliance resulted in a large, positive increase in compliance. We also found that there was substantial variability in the effect across units and that units with higher levels of preactivation compliance experienced increased benefits from monitoring relative to units with lower levels of prepreactivation compliance. By observing compliance rates over three and a half years, we investigated the persistent effects of individual monitoring and found that compliance rates initially increased before they gradually declined. Additionally, in multiple units, individual monitoring was discontinued, allowing for an investigation of the impact of removing the intervention on compliance. Surprisingly, we found that, after removal, compliance rates declined to below prepreactivation levels. Our findings suggest that, although individual electronic monitoring can dramatically improve process compliance, it requires sustained managerial commitment

The Impact of Time at Work and Time off From Work on Rule Compliance: The Case of Hand Hygiene in Healthcare

To deliver high-quality, reliable, and consistent services safely, organizations develop professional standards. Despite the communication and reinforcement of these standards, they are often not followed consistently. Although previous research suggests that high job demands are associated with declines in compliance over lengthy intervals, we hypothesized—drawing on theoretical arguments focused on fatigue and depletion—that the impact of job demands on routine compliance with professional standards might accumulate much more quickly. To test this hypothesis, we studied a problem that represents one of the most significant compliance challenges in health care today: hand hygiene. Using longitudinal field observations of over 4,157 caregivers working in 35 different hospitals and experiencing more than 13.7 million hand hygiene opportunities, we found that hand hygiene compliance rates dropped by a regression-estimated 8.7 percentage points on average from the beginning to the end of a typical 12-hr work shift. This decline in compliance was magnified by increased work intensity. Further, longer breaks between work shifts increased subsequent compliance rates, and such benefits were greater for individuals when they had ended their preceding shift with a lower compliance rate. In addition, (a) the decline in compliance over the course of a work shift and (b) the improvement in compliance following a longer break increased as individuals accumulated more total work hours the preceding week. The implications of these findings for patient safety and job design are discussed

ALMA Measurements of Circumstellar Material in the GQ Lup System

We present ALMA observations of the GQ Lup system, a young Sun-like star with a substellar mass companion in a wide-separation orbit. These observations of 870 $\mu$m continuum and CO J=3-2 line emission with beam size $\sim0.3''$ ($\sim45$ AU) resolve the disk of dust and gas surrounding the primary star, GQ Lup A, and provide deep limits on any circumplanetary disk surrounding the companion, GQ Lup b. The circumprimary dust disk is compact with a FWHM of $59\pm12$ AU, while the gas has a larger extent with a characteristic radius of $46.5\pm1.8$ AU. By forward-modeling the velocity field of the circumprimary disk based on the CO emission, we constrain the mass of GQ Lup A to be $M_* = (1.03\pm0.05)*(d/156\text{ pc})$ $M_\odot$, where $d$ is a known distance, and determine that we view the disk at an inclination angle of $60.5^\circ\pm0.5^\circ$ and a position angle of $346^\circ \pm1^\circ$. The $3\sigma$ upper limit on the 870 $\mu$m flux density of any circumplanetary disk associated with GQ Lup b of $<0.15$ mJy implies an upper limit on the dust disk mass of $<0.04$ $M_\oplus$ for standard assumptions about optically thin emission. We discuss proposed mechanisms for the formation of wide-separation substellar companions given the non-detection of circumplanetary disks around GQ Lup b and other similar systems.Comment: 11 pages, 4 figure

Short-range cluster spin glass near optimal superconductivity in BaFe2−x_{2-x}Nix_{x}As2_{2}

High-temperature superconductivity in iron pnictides occurs when electrons are doped into their antiferromagnetic (AF) parent compounds. In addition to inducing superconductivity, electron-doping also changes the static commensurate AF order in the undoped parent compounds into short-range incommensurate AF order near optimal superconductivity. Here we use neutron scattering to demonstrate that the incommensurate AF order in BaFe$_{2-x}$Ni$_{x}$As$_{2}$ is not a spin-density-wave arising from the itinerant electrons in nested Fermi surfaces, but consistent with a cluster spin glass in the matrix of the superconducting phase. Therefore, optimal superconductivity in iron pnictides coexists and competes with a mesoscopically separated cluster spin glass phase, much different from the homogeneous coexisting AF and superconducting phases in the underdoped regime.Comment: 4 figure

Coulomb Gap and Correlated Vortex Pinning in Superconductors

The positions of columnar pins and magnetic flux lines determined from a decoration experiment on BSCCO were used to calculate the single--particle density of states at low temperatures in the Bose glass phase. A wide Coulomb gap is found, with gap exponent $s \approx 1.2$, as a result of the long--range interaction between the vortices. As a consequence, the variable--range hopping transport of flux lines is considerably reduced with respect to the non--interacting case, the effective Mott exponent being enhanced from $p_0 = 1/3$ to $p_{\rm eff} \approx 0.5$ for this specific experiment.Comment: 10 pages, Revtex, 4 figures appended as uu-encoded postscript files, also available as hardcopies from [email protected]

Chiral symmetry breaking for deterministic switching of perpendicular magnetization by spin-orbit torque

Symmetry breaking is a characteristic to determine which branch of a bifurcation system follows upon crossing a critical point. Specifically, in spin-orbit torque (SOT) devices, a fundamental question arises: how to break the symmetry of the perpendicular magnetic moment by the in-plane spin polarization? Here, we show that the chiral symmetry breaking by the DMI can induce the deterministic SOT switching of the perpendicular magnetization. By introducing a gradient of saturation magnetization or magnetic anisotropy, non-collinear spin textures are formed by the gradient of effective SOT strength, and thus the chiral symmetry of the SOT-induced spin textures is broken by the DMI, resulting in the deterministic magnetization switching. We introduce a strategy to induce an out-of-plane (z) gradient of magnetic properties, as a practical solution for the wafer-scale manufacture of SOT devices.Comment: 16 pages, 4 figure