Multi-messenger observations of a binary neutron star merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

Search for gravitational waves associated with gamma-ray bursts detected by Fermi and Swift during the LIGO–Virgo run O3b

We search for gravitational-wave signals associated with gamma-ray bursts (GRBs) detected by the Fermi and Swift satellites during the second half of the third observing run of Advanced LIGO and Advanced Virgo (2019 November 1 15:00 UTC–2020 March 27 17:00 UTC). We conduct two independent searches: a generic gravitational-wave transients search to analyze 86 GRBs and an analysis to target binary mergers with at least one neutron star as short GRB progenitors for 17 events. We find no significant evidence for gravitational-wave signals associated with any of these GRBs. A weighted binomial test of the combined results finds no evidence for subthreshold gravitational-wave signals associated with this GRB ensemble either. We use several source types and signal morphologies during the searches, resulting in lower bounds on the estimated distance to each GRB. Finally, we constrain the population of low-luminosity short GRBs using results from the first to the third observing runs of Advanced LIGO and Advanced Virgo. The resulting population is in accordance with the local binary neutron star merger rate

Effectiveness of interventions to enhance healing of chronic foot ulcers in diabetes : a systematic review

The management of diabetic foot ulcers (DFU) remains a challenge, and there is continuing uncertainty concerning optimal approaches to wound healing. The International Working Group of the Diabetic Foot (IWGDF) working group on wound healing has previously published systematic reviews of the evidence in 2008, 2012 and 2016 to inform protocols for routine care and to highlight areas which should be considered for further study. The working group has now updated this review by considering papers on the interventions to improve the healing of DFU's published between June 2014 and August 2018. Methodological quality of selected studies was independently assessed by a minimum of two reviewers using the recently published 21-point questionnaire as recommended by IWGDF/European Wound Management Association, as well as the previously incorporated Scottish Intercollegiate Guidelines Network criteria. Of the 2275 papers identified, 97 were finally selected for grading following full text review. Overall, there has been an improvement in study design and a significant rise in the number of published studies. While previous systematic reviews did not find any evidence to justify the use of newer therapies, except for negative pressure wound therapy in post-surgical wounds, in this review we found additional evidence to support some interventions including a sucrose-octasulfate dressing, the combined leucocyte, fibrin and platelet patch as well as topical application of some placental membrane products, all when used in addition to usual best care. Nonetheless, the assessment and comparison of published trials remains difficult with marked clinical heterogeneity between studies: in patient selection, study duration, standard of usual care provision and the timing and description of the clinical endpoints