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

Unexplained somatic symptoms during major depression: prevalence and clinical impact in a national sample of Italian psychiatric outpatients

Background: The aim of this study was to explore the prevalence and impact of unexplained somatic symptoms during major depression. Sampling and Methods: A total of 560 consecutive outpatients with a major depressive episode according to the DSM-IV (text revision) were evaluated in 30 psychiatric facilities throughout Italy. 'Unexplained' somatic symptoms were evaluated using the 30-item Somatic Symptoms Checklist (SSCL-30). Somatic symptoms were considered explained if they were best accounted for as coming from a concomitant physical illness or side effects. Patients evaluated their own mood symptomatology using the Zung questionnaires for depression and anxiety and the Hypomania Checklist-32. Results: According to the SSCL-30, only 90 subjects (16.1%) had no unexplained somatic symptoms, while 231 (41.3%) had 1-5 unexplained symptoms and 239 (42.7%) had more than 5. Asthenia was the most commonly observed unexplained somatic symptom (53% of patients). Unexplained somatic symptoms were more common in females and among those suffering from major depression and depression not otherwise specified rather than in patients with recurrent major depression and bipolar disorders. No relationship between unexplained somatic symptoms and hypomanic features was observed. Conclusions: The presence of a large number of unexplained somatic symptoms is associated with more severe depression and higher rates of misdiagnosis and inappropriate treatment

Polymorphisms in predator induced defences of coexisting Daphnia pulex and D. longispina

A comparison of juvenile predator-avoidance polymorphisms of Daphnia pulex and D. longispina in a shallow water body of Northern Italy is reported. The presence of the Chaoborus larvae resulted in juvenile adaptive predator-avoidance cyclomorphosis in both species. The frequency of induced morphotypes was higher in the small-sized D. longispina than in the large-sized D. pulex. Relative tail-spine size was higher in D. longispina than in D. pulex. D. longispina displayed much more responsiveness to Chaoborus than D. pulex. Both species showed at least 6 different defensive morphotypes that were classified according to the neckteeth number, the neckteeth position and the thickness of occipital epithelia under neckteeth. The frequencies of different morphotypes varied significantly between species. The developmental responses of Daphnia to the presence of predators are regulated at various levels, according to specific timelines of kairomone sensitive phases and developmental frame of defense trait formation. Variation of a specific timeline might be linked to flexibility in developmental responses of Daphnia to Chaoborus and seasonal variation in the frequencies of various morphotypes. Cyclomorphosis should not only be due to changes in environmental factors that directly affects risk, but also to ones that act as proxy signaling changes in predation risk