172 research outputs found

    Multi-messenger observations of a binary neutron star merger

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    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

    Complexity analysis of the fetal heart rate variability: early identification of severe intrauterine growth-restricted fetuses

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    The main goal of this work is to suggest new indices for a correct identification of the intrauterine growth-restricted (IUGR) fetuses on the basis of fetal heart rate (FHR) variability analysis performed in the antepartum period. To this purpose, we analyzed 59 FHR time series recorded in early periods of gestation through a Hewlett Packard 1351A cardiotocograph. Advanced analysis techniques were adopted including the computation of the Lempel Ziv complexity (LZC) index and the multiscale entropy (MSE), that is, the entropy estimation with a multiscale approach. A multiparametric classifier based on k-mean cluster analysis was also performed to separate pathological and normal fetuses. The results show that the proposed LZC and the MSE could be useful to identify the actual IUGRs and to separate them from the physiological fetuses, providing good values of sensitivity and accuracy (Se = 77.8%, Ac = 82.4%)

    A randomized trial of long-term remote monitoring of pacemaker recipients (The COMPAS trial)

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    International audienceAIMS: Professional practice guidelines recommend that pacemaker recipients be followed regularly. However, the majority of scheduled ambulatory visits is unproductive and imposes a heavy burden on the health-care system. METHODS AND RESULTS: The COMPAS randomized, multicentre, non-inferiority trial examined the safety of long-term remote monitoring of pacemakers. Between December 2005 and January 2008, 538 patients were randomly assigned to remote monitoring follow-up (active group) vs. standard care (control group). The primary objective was to confirm that the proportion of patients who experienced at least one major adverse event (MAE), including all-cause death and hospitalizations for device-related or cardiovascular adverse events, was not >7% higher in the active than in the control group. MAE-free survivals and quality of life were compared in both groups. The characteristics of the study groups were similar. Over a follow-up of 18.3 months, 17.3% of patients in the active and 19.1% in the control group experienced at least one MAE (P < 0.01 for non-inferiority). Hospitalizations for atrial arrhythmias (6 vs. 18) and strokes (2 vs. 8) were fewer (P < 0.05), and the number of interim ambulatory visits was 56% lower (P < 0.001) in the active than the control group. Changes in pacemaker programming or drug regimens were made in 62% of visits in the active vs. 29% in the control group (P < 0.001). Quality of life remained unchanged in both groups. CONCLUSION: Remote monitoring was a safe alternative to conventional care and significantly lowered the number of ambulatory visits during long-term follow-up of permanently paced patients. ClinicalTrials.gov identifier: NCT00989326

    Capacidade funcional e uso de serviços de saúde por idosos da Região Metropolitana de Belo Horizonte, Minas Gerais, Brasil: um estudo de base populacional

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    O presente trabalho investigou a associação entre a capacidade funcional e utilização de serviços de saúde entre idosos residentes na Região Metropolitana de Belo Horizonte, Minas Gerais, Brasil. Participaram do estudo 1.624 idosos (≥ 60 anos) selecionados por meio de amostra probabilística. A variável dependente foi a utilização de serviços de saúde, baseada em três descritores: número de consultas médicas, consultas domiciliares e hospitalizações. A variável independente de interesse foi a capacidade funcional, medida pelo relato de dificuldade em realizar atividades instrumentais (AIVD) e básicas (ABVD) de vida diária. A primeira esteve associada apenas à hospitalização (RP = 1,62; IC95%: 1,16-2,26) e a segunda apresentou-se associada à hospitalização (RP = 1,73; IC95%: 1,24-2,42) e à consulta domiciliar (RP = 8,54; IC95%: 4,22-17,27). Os resultados mostraram maior utilização de serviços de saúde, sobretudo aqueles mais onerosos, entre idosos com incapacidade funcional, e que a dimensão funcional não tem sido balizadora da atuação dos serviços, ainda condicionada à presença de doenças
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