Abstract
We describe an image-based method that uses two radio criteria, compactness, and spectral index, to identify promising pulsar candidates among Fermi Large Area Telescope (LAT) unassociated ...sources. These criteria are applied to those radio sources from the Giant Metrewave Radio Telescope all-sky survey at 150 MHz (TGSS ADR1) found within the error ellipses of unassociated sources from the 3FGL catalogue and a preliminary source list based on 7 yr of LAT data. After follow-up interferometric observations to identify extended or variable sources, a list of 16 compact, steep-spectrum candidates is generated. An ongoing search for pulsations in these candidates, in gamma rays and radio, has found 6 ms pulsars and one normal pulsar. A comparison of this method with existing selection criteria based on gamma-ray spectral and variability properties suggests that the pulsar discovery space using Fermi may be larger than previously thought. Radio imaging is a hitherto underutilized source selection method that can be used, as with other multiwavelength techniques, in the search for Fermi pulsars.
The structural diversity of natural products offers unique opportunities for drug discovery, but challenges associated with their isolation and screening can hinder the identification of drug-like ...molecules from complex natural product extracts. Here we introduce a mass spectrometry-based approach that integrates untargeted metabolomics with multistage, high-resolution native mass spectrometry to rapidly identify natural products that bind to therapeutically relevant protein targets. By directly screening crude natural product extracts containing thousands of drug-like small molecules using a single, rapid measurement, we could identify novel natural product ligands of human drug targets without fractionation. This method should significantly increase the efficiency of target-based natural product drug discovery workflows.
Although iron deficiency is common in women especially during dieting, weight management trials rarely examine the longitudinal impact of genetics on iron. This study examined the associations ...between the TMPRSS6 rs855791 polymorphism and iron indices at baseline and after a 12-month trial comparing two weight loss diets (higher-protein, higher-haem iron (HPHI) vs lower-protein, lower-haem iron (LPLI)). A total of 76 young overweight women (18-25y; BMI⩾27.5 kg/m(2)) were included at baseline, with 27 (HPHI: n=15; LPLI: n=12) completing the 12-month trial. At baseline, C allele homozygotes exhibited higher serum iron (P=0.047) and lower hepcidin (P=0.023) compared with T allele carriers. After 12 months, no genotypic differences were observed for ferritin and soluble transferrin receptor, although C homozygotes on HPHI showed higher serum iron and transferrin saturation (P<0.05). Results indicate that rs855791 can influence iron metabolism to some extent, but its impact on storage and functional iron status is small relative to dietary protein/iron manipulation.
The TORCH time-of-flight detector Harnew, N.; Gao, R.; Hadavizadeh, T. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
03/2023, Volume:
1048
Journal Article
Peer reviewed
Open access
TORCH is a large-area time-of-flight (ToF) detector, proposed for the Upgrade-II of the LHCb experiment. It will provide charged hadron identification over a 2–20 GeV/c momentum range, given a 9.5m ...flight distance from the LHC interaction point. To achieve this level of performance, a 15ps timing resolution per track is required. A TORCH prototype module having a 1250×660×10mm3 fused-silica radiator plate and equipped with two MCP-PMTs has been tested in a 8GeV/c CERN test-beam. Single-photon time resolutions of between 70–100ps have been achieved, dependent on the beam position in the radiator. The measured photon yields agree with expectations.
Abstract
We present very long baseline interferometry observations of a faint and low-luminosity (L1.4 GHz < 1027 W Hz−1) gigahertz-peaked spectrum (GPS) and compact steep-spectrum (CSS) sample. We ...select eight sources from deep radio observations that have radio spectra characteristic of a GPS or CSS source and an angular size of θ ≲ 2 arcsec, and detect six of them with the Australian Long Baseline Array. We determine their linear sizes, and model their radio spectra using synchrotron self-absorption (SSA) and free–free absorption (FFA) models. We derive statistical model ages, based on a fitted scaling relation, and spectral ages, based on the radio spectrum, which are generally consistent with the hypothesis that GPS and CSS sources are young and evolving. We resolve the morphology of one CSS source with a radio luminosity of $10^{25}\, \hbox{W Hz}^{-1}$, and find what appear to be two hotspots spanning 1.7 kpc. We find that our sources follow the turnover–linear size relation, and that both homogeneous SSA and an inhomogeneous FFA model can account for the spectra with observable turnovers. All but one of the FFA models do not require a spectral break to account for the radio spectrum, while all but one of the alternative SSA and power-law models do require a spectral break to account for the radio spectrum. We conclude that our low-luminosity sample is similar to brighter samples in terms of their spectral shape, turnover frequencies, linear sizes, and ages, but cannot test for a difference in morphology.
A positive patient safety culture plays a major role in reducing medical errors and increasing productivity among healthcare staff. Furthermore, understanding staff perceptions of patient safety ...culture and effective patient safety factors is a first step toward enhancing quality of care and patient safety. The objectives of this study were to assess patient safety culture in hospitals in the United States and to investigate the effects of hospital and respondent characteristics on perceived patient safety culture. An analysis of 67,010 respondents in the 2018 Agency for Healthcare Research and Quality (AHRQ) comparative database was conducted with partial least squares structural equation modeling (PLS-SEM). The results revealed that perceptions of patient safety culture had a positive influence on the overall perceptions of patient safety and frequency of event reporting. Moreover, staff position, teaching status, and geographic region were found to have varying influence on the patient safety culture, overall perceptions of patient safety, and frequency of event reporting.
Abstract
We have studied radio haloes and relics in nine merging galaxy clusters using the Murchison Widefield Array (MWA). The images used for this study were obtained from the GaLactic and ...Extragalactic All-sky MWA (GLEAM) Survey which was carried out at five frequencies, viz. 88, 118, 154, 188 and 215 MHz. We detect diffuse radio emission in eight of these clusters. We have estimated the spectra of haloes and relics in these clusters over the frequency range 80–1400 MHz; the first such attempt to estimate their spectra at low frequencies. The spectra follow a power law with a mean value of α = −1.13 ± 0.21 for haloes and α = −1.2 ± 0.19 for relics, where S ∝ να. We reclassify two of the cluster sources as radio galaxies. The low-frequency spectra are thus an independent means of confirming the nature of cluster sources. Five of the nine clusters host radio haloes. For the remaining four clusters, we place upper limits on the radio powers of possible haloes in them. These upper limits are a factor of 2–20 below those expected from the LX–P1.4 relation. These limits are the lowest ever obtained and the implications of these limits to the hadronic model of halo emission are discussed.
We present a search for transient and highly variable sources at low radio frequencies (150-200 MHz) that explores long time-scales of 1-3 yr. We conducted this search by comparing the TIFR GMRT Sky ...Survey Alternative Data Release 1 (TGSS ADR1) and the GaLactic and Extragalactic All-sky Murchison Widefield Array (GLEAM) survey catalogues. To account for the different completeness thresholds in the individual surveys, we searched for compact GLEAM sources above a flux density limit of 100 mJy that were not present in the TGSS ADR1; and also for compact TGSS ADR1 sources above a flux density limit of 200 mJy that had no counterpart in GLEAM. From a total sample of 234 333 GLEAM sources and 275 612 TGSS ADR1 sources in the overlap region between the two surveys, there were 99 658 GLEAM sources and 38 978 TGSS ADR sources that passed our flux density cut-off and compactness criteria. Analysis of these sources resulted in three candidate transient sources. Further analysis ruled out two candidates as imaging artefacts. We analyse the third candidate and show it is likely to be real, with a flux density of 182 plus or minus 26 mJy at 147.5 MHz. This gives a transient surface density of p = (6.2 plus or minus 6) x 10 super( -5) deg super( -2). We present initial follow-up observations and discuss possible causes for this candidate. The small number of spurious sources from this search demonstrates the high reliability of these two new low-frequency radio catalogues.
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