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The Rapid ASKAP Continuum Survey (RACS) is the first large-area survey to be conducted with the full 36-antenna Australian Square Kilometre Array Pathfinder (ASKAP) telescope. RACS will provide a shallow model of the ASKAP sky that will aid the calibration of future deep ASKAP surveys. RACS will cover the whole sky visible from the ASKAP site in Western Australia and will cover the full ASKAP band of 700–1800 MHz. The RACS images are generally deeper than the existing NRAO VLA Sky Survey and Sydney University Molonglo Sky Survey radio surveys and have better spatial resolution. All RACS survey products will be public, including radio images (with
15 arcsec resolution) and catalogues of about three million source components with spectral index and polarisation information. In this paper, we present a description of the RACS survey and the first data release of 903 images covering the sky south of declination
made over a 288-MHz band centred at 887.5 MHz.
The global community needs to be aware of the potential psychosocial consequences that may be experienced by health care workers who are actively managing patients with coronavirus disease (COVID-19). These health care workers are at increased risk for experiencing mood and trauma-related disorders, including posttraumatic stress disorder (PTSD). In this concept article, strategies are recommended for individual health care workers and hospital leadership to aid in mitigating the risk of PTSD, as well as to build resilience in light of a potential second surge of COVID-19.
We describe an ultra-wide-bandwidth, low-frequency receiver recently installed on the Parkes radio telescope. The receiver system provides continuous frequency coverage from 704 to 4032 MHz. For much of the band (
), the system temperature is approximately 22 K and the receiver system remains in a linear regime even in the presence of strong mobile phone transmissions. We discuss the scientific and technical aspects of the new receiver, including its astronomical objectives, as well as the feed, receiver, digitiser, and signal processor design. We describe the pipeline routines that form the archive-ready data products and how those data files can be accessed from the archives. The system performance is quantified, including the system noise and linearity, beam shape, antenna efficiency, polarisation calibration, and timing stability.
A summary is given of the present state of our knowledge of High-Mass X-ray Binaries (HMXBs), their formation and expected future evolution. Among the HMXB-systems that contain neutron stars, only those that have orbital periods upwards of one year will survive the Common-Envelope (CE) evolution that follows the HMXB phase. These systems may produce close double neutron stars with eccentric orbits. The HMXBs that contain black holes do not necessarily evolve into a CE phase. Systems with relatively short orbital periods will evolve by stable Roche-lobe overflow to short-period Wolf-Rayet (WR) X-ray binaries containing a black hole. Two other ways for the formation of WR X-ray binaries with black holes are identified: CE-evolution of wide HMXBs and homogeneous evolution of very close systems. In all three cases, the final product of the WR X-ray binary will be a double black hole or a black hole neutron star binary.
Tidewater glaciers in Greenland experienced widespread retreat during the last century. Information on their behaviour prior to this is often poorly constrained due to lack of observations, while determining the drivers prior to instrumental records is also problematic. Here we present a record of the dynamics of Kangiata Nunaata Sermia (KNS), southwest Greenland, from its Little Ice Age maximum (LIAmax) to 1859 – the period before continuous air temperature observations began at Nuuk in 1866. Using glacial geomorphology, historical accounts, photographs and GIS analyses, we provide evidence KNS was at its LIAmax by 1761, had retreated by ~5 km by 1808 and a further 7 km by 1859. This predates retreat at Jakobshavn Isbræ by 43–113 years, demonstrating the asynchroneity of tidewater glacier terminus response following the LIA. We use a one-dimensional flowband model to determine the relative sensitivity of KNS to atmospheric and oceanic climate forcing. Results demonstrate that terminus forcing rather than surface mass balance drove the retreat. Modelled glacier sensitivity to submarine melt rates is also insufficient to explain the retreat observed. However, moderate increases in crevasse water depth, driving an increase in calving, are capable of causing terminus retreat of the observed magnitude and timing.
Recent studies have demonstrated that central line-associated bloodstream infections (CLABSIs) are preventable through implementation of evidence-based prevention practices. Hospitals have reported CLABSI data to the Centers for Disease Control and Prevention (CDC) since the 1970s, providing an opportunity to characterize the national impact of CLABSIs over time. Our objective was to describe changes in the annual number of CLABSIs in critical care patients in the United States.
Monte Carlo simulation.
US acute care hospitals.
Nonneonatal critical care patients.
We obtained administrative data on patient-days for nearly all US hospitals and applied CLABSI rates from the National Nosocomial Infections Surveillance and the National Healthcare Safety Network systems to estimate the annual number of CLABSIs in critical care patients nationally during the period 1990–2010 and the number of CLABSIs prevented since 1990.
We estimated that there were between 462,000 and 636,000 CLABSIs in nonneonatal critical care patients in the United States during 1990–2010. CLABSI rate reductions led to between 104,000 and 198,000 fewer CLABSIs than would have occurred if rates had remained unchanged since 1990. There were 15,000 hospital-onset CLABSIs in nonneonatal critical care patients in 2010; 70% occurred in medium and large teaching hospitals.
Substantial progress has been made in reducing the occurrence of CLABSIs in US critical care patients over the past 2 decades. The concentration of critical care CLABSIs in medium and large teaching hospitals suggests that a targeted approach may be warranted to continue achieving reductions in critical care CLABSIs nationally.
A low temperature amorphous zinc indium oxide (ZIO) thin film transistor (TFT) backplane technology for high information content flexible organic light emitting diode (OLED) displays has been developed. We have fabricated 4.1-in. diagonal OLED backplanes on the Flexible Display Center’s six-inch wafer-scale pilot line using ZIO as the active layer. The ZIO based TFTs exhibited an effective saturation mobility of 18.6 cm2/V-s and a threshold voltage shift of 2.2 Volts or less under positive and negative gate bias DC stress for 10000 seconds. We report on the critical steps in the evolution of the backplane process: the qualification of the low temperature (200°C) ZIO process, the stability of the devices under forward and reverse bias stress, the transfer of the process to flexible plastic substrates, and the fabrication of white organic light emitting diode (OLED) displays.