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

Tabagismo e consumo de álcool em estudantes universitários: prevalência e fatores associados Smoking and alcohol consumption among university students: prevalence and associated factors

O presente estudo teve o objetivo de verificar a prevalência de tabagismo e consumo de álcool entre estudantes da Universidade Federal de Pelotas (UFPel), além de investigar os fatores associados a esses comportamentos. A amostra foi composta por 485 alunos que ingressaram na UFPel em 2008. Os alunos foram selecionados de maneira aleatória entre cursos de todas as áreas da UFPel e responderam a um questionário pré-testado na sala de aula, sob supervisão da equipe de pesquisa. Dos indivíduos entrevistados, 53,9% eram do sexo feminino e 42,3% tinham menos de 20 anos. Em relação ao consumo de álcool, 75% da amostra o utilizam pelo menos uma vez por mês; a prevalência de risco para o alcoolismo foi de 6,2%. Em relação ao tabagismo, 10,2% dos estudantes relataram fumar regularmente ou nos fins-de-semana. Além disso, mais de 90% dos fumantes e dos que consomem bebidas alcoólicas iniciaram o hábito antes de ingressar na universidade. O tabagismo apresentou uma relação direta com a idade e inversa com a autopercepção de saúde. Em relação ao álcool, estudantes que moram com amigos relataram um maior consumo. Os dados sugerem a necessidade de intervenções no meio acadêmico. Entretanto, cabe destacar que as ações para a população adolescente como um todo devam ser priorizadas, pois mais de 90% dos alunos adquiriram os hábitos antes de ingressarem na universidade, demonstrando que o início do consumo está ocorrendo em idades mais precoces.<br>The study aimed to estimate the prevalence of smoking and alcohol intake among university students from the Federal University of Pelotas, Brazil (UFPel), as well as to investigate factors associated with both habits. The sample included 485 students who were admitted to the university in 2008. Students were sampled randomly across all schools of the UFPel campus, and answered a pre-tested questionnaire, which was administered in the classroom by a member of the research team. Of the individuals interviewed, 53.9% were females and 42.3% were under 20 years. Regarding alcohol intake, 75% used alcohol once a month or less frequently, and the prevalence of risk for abusive alcohol intake was 6.2%. Regarding smoking, 10.2% reported smoking regularly or on weekends. More than 90% of those who smoked or used alcohol started before entering the university. Smoking was directly related to age and inversely related to self-rated health. In terms of alcohol intake, those who lived with friends were more likely to use it. Our data suggest the need for implementing strategies to promote healthy lifestyles among university students. However, the fact that more than 90% of individuals started to smoke or drink before entering the university suggests that interventions should target adolescents as a whole, and not only those who are university students, because onset of smoking and alcohol intake seems to occur at earlier ages

Consumo frequente de bebidas alcoólicas por adolescentes escolares: estudo de fatores associados Frequent consumption of alcohol by school age adolescents: study of associated factors

OBJETIVO: Analisar fatores associados ao consumo frequente de bebidas alcoólicas por adolescentes escolares em Feira de Santana, BA. MÉTODO: Estudo transversal, com amostra aleatória, estratificada por conglomerado, totalizando 10 escolas de portes diferenciados e 776 estudantes de ambos os sexos que relataram consumo de bebidas alcoólicas, na faixa etária de 14 a 19 anos, assegurando representatividade das escolas e alunos. O instrumento auto-aplicável foi elaborado segundo a Organização Mundial de Saúde (OMS) e questionários validados em outros estudos. A coleta garantiu procedimentos para anonimato e sigilo. Foram considerados expostos adolescentes que referiram consumo frequente (em pelo menos todo final de semana). RESULTADOS: O consumo frequente/pesado mostrou associações significantes com sexo masculino, consumo precoce, parceiro sexual pouco conhecido, problemas com substâncias psicoativas (SPAs) na família, coabitação com companheiro, renda própria, tráfico de drogas, consumo com amigos, atividades na escola, motivações (ansiedade, animação/prazer); e consequências (outras SPAs, brigas, inadimplência ao trabalhoescola). CONCLUSÕES: O conhecimento dos fatores pessoais, interpessoais, familiares e ambientais associados ao consumo de bebidas alcoólicas por adolescentes devem ser considerados na implementação de programas escolares e políticas públicas de prevenção, visando comportamentos que minimizem a exposição ao risco associado.<br>OBJECTIVES: To analyze factors associated with the frequent consumption of alcohol by school age adolescents in Feira de Santana, Bahia. METHOD: Cross sectional study with random sampling, stratified by clusters, totaling 10 schools of different sizes. Although 1,409 students were included in the sample, only 776 of both genders, aged 14 to 19 years who reported alcohol drinking were included in the analysis, providing representativeness of schools and students. Data collection tools were a self-administered questionnaire designed in compliance with WHO recommendations and other valid questionnaires from similar studies. Anonymous confidential data collecting was assured. Adolescents who reported frequent alcohol drinking (at least every weekend) were considered exposed. RESULTS: Frequent alcohol drinking was associated with the male gender; early consumption; little-known sexual partner; problems with other drugs in the family; living with a partner; own income; drug trafficking; consumption with friends, activities at school, motivations (anxiety, excitement/pleasure), and consequences (other drugs, fights, debts in work/school) CONCLUSIONS: Knowledge of personal, interpersonal, family and environmental factors associated with alcohol use in adolescents should be considered in the implementation of school programs and public policies for alcohol use prevention focusing on behaviors that could minimize exposure to risk

The Large Observatory For x-ray Timing

The Large Observatory For x-ray Timing (LOFT) was studied within ESA M3 Cosmic Vision framework and participated in the final downselection for a launch slot in 2022-2024. Thanks to the unprecedented combination of effective area and spectral resolution of its main instrument, LOFT will study the behaviour of matter under extreme conditions, such as the strong gravitational field in the innermost regions of accretion flows close to black holes and neutron stars, and the supranuclear densities in the interior of neutron stars. The science payload is based on a Large Area Detector (LAD, 10 m2 effective area, 2-30 keV, 240 eV spectral resolution, 1° collimated field of view) and a Wide Field Monitor (WFM, 2-50 keV, 4 steradian field of view, 1 arcmin source location accuracy, 300 eV spectral resolution). The WFM is equipped with an on-board system for bright events (e.g. GRB) localization. The trigger time and position of these events are broadcast to the ground within 30 s from discovery. In this paper we present the status of the mission at the end of its Phase A stud

Multimessenger observations of a flaring blazar coincident with high-energy neutrino IceCube-170922A

Previous detections of individual astrophysical sources of neutrinos are limited to the Sun and the supernova 1987A, whereas the origins of the diffuse flux of high-energy cosmic neutrinos remain unidentified. On 22 September 2017, we detected a high-energy neutrino, IceCube-170922A, with an energy of ~290 tera–electron volts. Its arrival direction was consistent with the location of a known γ-ray blazar, TXS 0506+056, observed to be in a flaring state. An extensive multiwavelength campaign followed, ranging from radio frequencies to γ-rays. These observations characterize the variability and energetics of the blazar and include the detection of TXS 0506+056 in very-high-energy γ-rays. This observation of a neutrino in spatial coincidence with a γ-ray–emitting blazar during an active phase suggests that blazars may be a source of high-energy neutrinos