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

Incidence of bleeding after minor oral surgery in patients on dual antiplatelet therapy: a systematic review and meta-analysis

Bleeding is a feared complication of minor oral surgery in patients on treatment with antiplatelet agents and there is no agreed strategy regarding the cessation or not of antiplatelet treatment. The aim of this systematic review was to evaluate bleeding with minor oral surgery in patients on dual antiplatelet therapy (DAPT), single antiplatelet therapy (SAPT), or no antiplatelet therapy (no APT). The PubMed, Embase, Web of Science, and Cochrane Library databases were screened. Sixteen studies were included. DAPT was continued in all studies. The perioperative bleeding risk was significantly higher for DAPT than for SAPT (risk ratio (RR) 10.16, P= 0.010; risk difference (RD) 0.35, P= 0.269), but not higher compared to no APT (RR 6.50, P= 0.057; RD 0.19, P= 0.060). The postoperative bleeding risk was significantly elevated for DAPT compared to SAPT (RR 2.61, P= 0.010) and no APT (RR 3.63, P= 0.035), but only by 1% (RD 0.01, P= 0.103) and 1% (RD 0.01, P= 0.421), respectively. Clinically, this may be considered quite similar. Additionally, local haemostatic measures could control all reported bleeding and no lethal events occurred. Therefore, DAPT interruption is not advised before minor oral surgery.status: publishe

Spatial, Temporal, and Density-Dependent Components of Habitat Quality for a Desert Owl

<div><p>Spatial variation in resources is a fundamental driver of habitat quality but the realized value of resources at any point in space may depend on the effects of conspecifics and stochastic factors, such as weather, which vary through time. We evaluated the relative and combined effects of habitat resources, weather, and conspecifics on habitat quality for ferruginous pygmy-owls (<i>Glaucidium brasilianum</i>) in the Sonoran Desert of northwest Mexico by monitoring reproductive output and conspecific abundance over 10 years in and around 107 territory patches. Variation in reproductive output was much greater across space than time, and although habitat resources explained a much greater proportion of that variation (0.70) than weather (0.17) or conspecifics (0.13), evidence for interactions among each of these components of the environment was strong. Relative to habitat that was persistently low in quality, high-quality habitat buffered the negative effects of conspecifics and amplified the benefits of favorable weather, but did not buffer the disadvantages of harsh weather. Moreover, the positive effects of favorable weather at low conspecific densities were offset by intraspecific competition at high densities. Although realized habitat quality declined with increasing conspecific density suggesting interference mechanisms associated with an Ideal Free Distribution, broad spatial heterogeneity in habitat quality persisted. Factors linked to food resources had positive effects on reproductive output but only where nest cavities were sufficiently abundant to mitigate the negative effects of heterospecific enemies. Annual precipitation and brooding-season temperature had strong multiplicative effects on reproductive output, which declined at increasing rates as drought and temperature increased, reflecting conditions predicted to become more frequent with climate change. Because the collective environment influences habitat quality in complex ways, integrated approaches that consider habitat resources, stochastic factors, and conspecifics are necessary to accurately assess habitat quality.</p></div

Rankings of best approximating models of the effects of temporal and spatial factors on reproductive output of ferruginous pygmy-owls in northwest Mexico, 2001–2010 compared to other models where some effects were included, excluded, or changed.

<p>Rankings of best approximating models of the effects of temporal and spatial factors on reproductive output of ferruginous pygmy-owls in northwest Mexico, 2001–2010 compared to other models where some effects were included, excluded, or changed.</p

Interactive effects of important factors associated with different environmental components of habitat quality on reproductive output of ferruginous pygmy-owls in northwest Mexico, 2001–2010.

<p>The hypothetical weather gradient in the top figure was standardized based on annual precipitation and mean maximum temperature during the brooding season so as to represent conditions that ranged from wet and cool to hot and dry. Estimates are based on the top-ranked models that included these interactions in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0119986#pone.0119986.t006" target="_blank">Table 6</a>.</p

Effects of conspecifics on reproductive output of ferruginous pygmy-owls in northwest Mexico, 2001–2010.

<p>Conspecific density was measured around each focal patch each year and regional occupancy was measured as the proportion of patches occupied in each of 11 watershed regions in each year. Estimates of the effect of local conspecific density are based on model {Density} and estimates of the effect of regional occupancy are adjusted for the effects of local density from model {Density + Occ_region} in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0119986#pone.0119986.s004" target="_blank">S4 Appendix</a>.</p

Study area in northwest Mexico showing distribution of territory patches used by ferruginous pygmy-owls and the location of weather stations.

<p>Territory patches were located in two major vegetation communities and weather stations were located near Sasabe, Sonoyta, Cucurpe, Magdelena, and Altar. Regional patch occupancy was estimated in 11 regions: San Miguel, upper Magdalena, Magdalena-Coyotillo, Busani, upper Alter, lower Altar, upper Sasabe, lower Sasabe, upper Plomo, lower Plomo, and Sonoyta. Territory patches were 50 ha in area and are not shown to scale; the study area was approximately 20,000 km².</p

Rankings of models that described the individual, additive, and interactive effects of spatial and temporal factors and conspecifics on reproductive output of ferruginous pygmy-owls in northwest Mexico, 2001–2010.

<p>Factors included in models for each component are those in the best approximating models. Models and parameter estimates are in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0119986#pone.0119986.s005" target="_blank">S5 Appendix</a>.</p><p>Rankings of models that described the individual, additive, and interactive effects of spatial and temporal factors and conspecifics on reproductive output of ferruginous pygmy-owls in northwest Mexico, 2001–2010.</p