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

Effects of a school-based prevention program on European adolescents' patterns of alcohol use

Purpose: School-based substance abuse prevention programs are widespread but are rarely evaluated in Europe. We aimed to evaluate the effect of a new school-based prevention program against substance use on the frequency of alcohol consumption and alcohol-related problem behaviors among European students. Methods: During the school year 2004\u20132005, a total of 7,079 students aged 12\u201314 years from 143 schools in seven European countries participated in this cluster randomized controlled trial. Schools were randomly assigned to either control (65 schools, 3,532 students) or to a 12-session standardized program based on the comprehensive social influence model (78 schools, 3,547 students). Alcohol use and frequency of alcohol related problem behaviors were investigated through a self-completed anonymous questionnaire at baseline and 18 months thereafter. The association between intervention and changes in alcohol-related outcomes was expressed as odds ratio (OR), estimated by multilevel regression model. Results: The preventive program was associated with a decreased risk of reporting alcohol-related problems (OR.78, 95% confidence intervals [CI].63\u2013.98), although this reduction was not statistically significant in the subgroup of 743 current drinkers at baseline. The risk for alcohol consumption was not modified by exposure to the program (OR.93, 95% CI.79 \u20131.09). In the intervention group, nondrinkers and occasional drinkers at baseline progressed toward frequent drinking less often than in the control group. Conclusions: School curricula based on the comprehensive social-influence model can delay progression to frequent drinking and reduce occurrence of alcohol-related behavioral problems in European students. These results, albeit moderate, have potentially useful implications at the population level

Effetti di un programma di prevenzione a base scolastica sull’uso di alcol tra adolescenti europei

OBIETTIVI: Secondo la dichiarazione della Conferenza Ministeriale WHO/Europa sui Giovani e l’Alcol, tutti i bambini e gli adolescenti hanno il diritto a crescere in un ambiente protetto dalle conseguenze negative del consumo di alcol. I programmi a base scolastica per la prevenzione dell’abuso di sostanze sono molto diffusi in Europa, ma raramente sono sottoposti a prove di valutazione di efficacia. EU-Dap è un progetto finanziato dall’Unione Europea per valutare l’efficacia di un nuovo programma a base scolastica per la prevenzione dell’uso di sostanze tra studenti europei. In questo studio riportiamo gli effetti del curriculum sulla frequenza di consumo di alcol, di episodi di ubriachezza e sui comportamenti problematici alcolcorrelati, 18 mesi dopo l’inizio dello programma. MATERIALI: Durante l’anno scolastico 2004-2005, 7079 studenti di 12-14 anni provenienti da 143 scuole di 7 paesi europei hanno partecipato a questo studio sperimentale randomizzato controllato. Le scuole sono state assegnate a caso alla condizione di controllo (3532 studenti) o ad un curriculum standardizzato di 12 lezioni basato sul modello dell’influenza sociale comprensivo (3547 studenti). L’uso di alcol, la frequenza di episodi di ubriachezza e di comportamenti problematici alcol-correlati sono stati indagati attraverso un questionario anonimo auto compilato, all’inizio dello studio e 18 mesi dopo. L’associazione tra intervento e cambiamenti nelle risposte relative all’uso di alcol è stata espressa in termini di odds ratio, stimati con modelli di regressione multipla di tipo multilivello. RIASSUNTO: Il programma di prevenzione è associato ad un rischio diminuito di riferire episodi di ubriachezza nei 30 giorni precedenti l’intervista (OR=0.80, 95% CI=0.67–0.97) e comportamenti problematici dovuti all’alcol nei 12 mesi precedenti l’intervista (OR=0.78, 95% CI=0.63-0.98). Il rischio di consumo di alcol non è stato modificato dall’esposizione al programma (OR=0.93, 95% CI=0.79-1.09). Tuttavia, tra coloro che all’inizio dello studio non bevevano o bevevano occasionalmente, gli studenti nel braccio d’intervento hanno dimostrato, rispetto ai controlli, una minor tendenza a progredire verso il bere frequente. CONCLUSIONI: I programmi scolastici basati sul modello dell’influenza sociale comprensivo possono ridurre l’occorrenza di episodi di ubriachezza e di problemi comportamentali alcol-correlati tra gli adolescenti europei