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

Early outcomes of laparoscopic donor nephrectomy with multiple renal arteries

PURPOSE: We evaluated our experience with laparoscopic donor nephrectomy in patients with multiple renal arteries, comparing operative outcomes and early graft function with patients with a single renal artery. MATERIALS AND METHODS: From January 2003 to February 2009, 130 patients underwent laparoscopic donor nephrectomy at our institution, 108 (83%) with a single renal artery and 22 (17%) with multiple arteries. Donor and recipient outcomes for single artery and multiple arteries allografts were compared. RESULTS: The LDN operative time was similar between the single artery and multiple arteries groups (162 vs 163 min, respectively, p = 0.87). Allografts with multiple arteries had significantly longer warm ischemia time (3.9 vs 4.9 min, p = 0.05) and cold ischemia time (72 vs 94 min, p < 0.001) than those with single artery. The conversion rate was similar between single and multiple arteries groups (6% vs 4.5%, respectively, p = 0.7). Multiple arteries grafts had a non statistically significant higher rate of poor graft function when compared to single artery grafts (23% vs 12%, respectively, p = 0.18). Five patients in the single artery group (4.6%) and one patient in the multiple arteries group (4.5%) needed dialysis during the first postoperative week. Overall, recipient complication rates were similar between single and multiple arteries groups (12.9% vs 18.1%, respectively, p = 0.51). CONCLUSION: Laparoscopic donor nephrectomy with multiple arteries was associated with a non statistically significant higher rate of poor early graft function. The procedure appears to be safe in patients with multiple arteries, with similar complications rates. Multiple arteries should not be a contraindication for laparoscopic donor nephrectomy