11 research outputs found
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
Alimentação e nutrição como campo científico autônomo no Brasil: conceitos, domínios e projetos políticos
Efeitos do alcoolismo e da desintoxicação alcoólica sobre o reparo e biomecânica óssea Effects of alcoholism and alcoholic detoxication on the repair and biomechanics of bone
OBJETIVO: Avaliar os efeitos do consumo crônico de etanol e da desintoxicação alcoólica sobre a resistência mecânica do osso e neoformação óssea junto a implantes de hidroxiapatita densa (HAD) realizados em ratos. MÉTODOS: Foram utilizados 15 ratos divididos em três grupos, sendo controle (CT), alcoolista crônico (AC) e desintoxicado (DE). Após quatro semanas, foi realizada implantação de HAD na tíbia e produzida falha no osso parietal, em seguida o grupo AC continuaram a consumir etanol e o grupo DE iniciaram a desintoxicação. Ao completar 13 semanas os animais sofreram eutanásia, os ossos foram coletados para o processamento histomorfométrico e os fêmures encaminhados ao teste mecânico de resistência. RESULTADOS: Os animais do grupo AC apresentaram menores valores de neoformação óssea, de calcemia e resistência mecânica, quando comparado aos grupos CT e DE. Os animais dos grupos DE apresentaram valores superiores em todas as variáveis avaliadas em relação ao grupo AC. CONCLUSÃO: O consumo de etanol interferiu na osteogênese ao redor de implante de HAD, nos níveis de cálcio e na resistência mecânica óssea. A desintoxicação alcoólica se mostrou eficaz, pois aumentou à osteogênese e osseointegração da HAD, a calcemia e resistência mecânica óssea. Nivel de Evidência I, estudo terapeutico.<br>OBJECTIVE: To evaluate the effects of chronic ethanol consumption and alcohol detoxication on the mechanical resistance of bone and bone neoformation around dense hydroxyapatite implants (DHA) in rats. METHODS: Fifteen rats were separated into three groups: (1) control group (CT); (2) chronic alcoholic (CA), and (3) disintoxicated (DI). After four weeks, a DHA was implanted in the right tibia of the animals, and the CA group continued consuming ethanol, while the DI group started detoxication. The solid and liquid feeding of the animals was recorded, and a new alcohol dilution was effected every 48 hours. After 13 weeks, the animals were euthanized and their biological material was collected. RESULTS: Bone tissue was found around DHA in all the animals. Group CA showed less bone neoformation, lower levels of ionic and total calcium when compared to the animals of the CT and DI groups. The DI animals showed higher values in all the variables in relation to the CA group. CONCLUSION: Ethanol consumption interfered in osteogenesis around the DHA implants, and in calcium levels and mechanical bone resistance. Alcohol detoxication was effective, as it increased osteogenesis, DHA osteointegration, calcemia, and mechanical resistance of the bone. Level of Evidence: Level I, therapeutic studie
A vida não pode ser feita só de sonhos: reflexões sobre publicidade e alimentação saudável Life cannot consist of dreams alone: reflections on advertising and a healthy diet
Neste ensaio apresentamos algumas reflexões sobre publicidade e alimentação saudável no mundo contemporâneo onde o consumo exerce papel de grande relevância. Buscamos enfatizar dois aspectos, entre tantos outros ainda por serem explorados na literatura científica do campo alimentar-nutricional: a hegemonia do paradigma biomédico e a fragmentação da vida humana quando campanhas publicitárias anunciam alimentos associando-os à ideia de alimentação saudável. Consideramos que não podemos viver somente como naquela publicidade onde nossos desejos são acionados, sem limites, onde mundo é só de sonhos e o objetivo principal é vender mais e lucrar mais, ainda que para isso se tenha feito uso de estratégias de disseminação de algumas informações de cunho biomédico-nutricional. O encontro entre alimentação e saúde, ou seja, alimentação saudável, deve pressupor, no nosso entendimento, a valorização da ação do sujeito, inclusive por meio de informações qualificadas e contextualizadas na vida social de modo a que se possa desenhar projetos de felicidade. Um sujeito fortalecido em sua identidade, íntegro e total que, entre sonhos e concretudes, pode ousar a buscar o conhecer e o pensar sobre si mesmo no mundo, sobre sua alimentação e sua saúde.<br>In this essay we present some thoughts on advertising and a healthy diet in the contemporary world, where consumption plays a highly relevant role. We seek to emphasize two aspects, among many others yet to be explored in the scientific literature in the food and nutritional field: the hegemony of the biomedical paradigm and the fragmentation of human life when advertising campaigns associate food with the idea of a healthy diet. We believe that we cannot merely live through advertisements in which our desires are triggered constantly and where the world is only dreams and the main goal is to sell more and earn more, even using some strategies for dissemination of biomedical and nutritional information. In our opinion, the merger between diet and health, i.e. a healthy diet, must involve enlightenment of the individual including information on quality in the context of social life in order to achieve the ideal of happiness. Individuals whose identities are fully formed both in dreams and reality can boldly seek knowledge and think about themselves in the world context, as well as zeal for their diet and health