2 research outputs found

    Massive stars exploding in a He-rich circumstellar medium \u2013 VII. The metamorphosis of ASASSN-15ed from a narrow line Type Ibn to a normal Type Ib Supernova

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    We present the results of the spectroscopic and photometric monitoring campaign of ASASSN-15ed. The transient was discovered quite young by the All Sky Automated Survey for Super-Novae (ASAS-SN) survey. Amateur astronomers allowed us to sample the photometric SN evolution around maximum light, which we estimate to have occurred on JD=2457087.4 +/- 0.6 in the r band. Its apparent r-band magnitude at maximum was r = 16.91 +/- 0.10, providing an absolute magnitude M-r approximate to -20.04 +/- 0.20, which is slightly more luminous than the typical magnitudes estimated for Type Ibn SNe. The post-peak evolution was well monitored, and the decline rate (being in most bands around 0.1 mag d(-1) during the first 25 d after maximum) is marginally slower than the average decline rates of SNe Ibn during the same time interval. The object was initially classified as a Type Ibn SN because early-time spectra were characterized by a blue continuum with superimposed narrow P-Cygni lines of He I, suggesting the presence of a slowly moving (1200-1500 km s(-1)), He-rich circumstellar medium. Later on, broad P-Cygni He I lines became prominent. The inferred velocities, as measured from the minimum of the broad absorption components, were between 6000 and 7000 km s(-1). As we attribute these broad features to the SN ejecta, this is the first time we have observed the transition of a Type Ibn SN to a Type Ib SN.PRIN-INAF; project 'Transient Universe: unveiling new types of stellar explosions with PESSTO'; FONDECYT [1151445]; Ministry of Economy, Development, and Tourisms Millennium Science Initiative [IC120009]; European Union Seventh Framework Programme (FP7), 'Astronomy Fellowships in Italy' (AstroFIt) [267251]; Spanish Ministerio de Economia y Competitividad (MINECO) [ESP2013-41268-R]; German Research Foundation (DFG) [TRR33]; NSF [PHY-1404311, AST-0908816]; 'Strategic Priority Research Program - The Emergence of Cosmological Structures' of the Chinese Academy of Sciences [XDB09000000]; DOE Computational Science Graduate Fellowship [DE-FG02-97ER25308]; Brazilian agency CAPES [9229-13-2]; NASA through Hubble Fellowship - Space Telescope Science Institute [HF-51348.001]; NASA [NAS 5-26555]; Laboratory Directed Research and Development program at LANL; UK Science and Technology Facilities CouncilSCI(E)[email protected]

    Suicidal ideation in a European Huntington's disease population

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    Previous studies indicate increased prevalences of suicidal ideation, suicide attempts, and completed suicide in Huntington's disease (HD) compared with the general population. This study investigates correlates and predictors of suicidal ideation in HD. METHODS: The study cohort consisted of 2106 HD mutation carriers, all participating in the REGISTRY study of the European Huntington's Disease Network. Of the 1937 participants without suicidal ideation at baseline, 945 had one or more follow-up measurements. Participants were assessed for suicidal ideation by the behavioural subscale of the Unified Huntington's Disease Rating Scale (UHDRS). Correlates of suicidal ideation were analyzed using logistic regression analysis and predictors were analyzed using Cox regression analysis. RESULTS: At baseline, 169 (8.0%) mutation carriers endorsed suicidal ideation. Disease duration (odds ratio [OR]=0.96; 95% confidence interval [CI]: 0.9-1.0), anxiety (OR=2.14; 95%CI: 1.4-3.3), aggression (OR=2.41; 95%CI: 1.5-3.8), a previous suicide attempt (OR=3.95; 95%CI: 2.4-6.6), and a depressed mood (OR=13.71; 95%CI: 6.7-28.0) were independently correlated to suicidal ideation at baseline. The 4-year cumulative incidence of suicidal ideation was 9.9%. Longitudinally, the presence of a depressed mood (hazard ratio [HR]=2.05; 95%CI: 1.1-4.0) and use of benzodiazepines (HR=2.44; 95%CI: 1.2-5.0) at baseline were independent predictors of incident suicidal ideation, whereas a previous suicide attempt was not predictive. LIMITATIONS: As suicidal ideation was assessed by only one item, and participants were a selection of all HD mutation carriers, the prevalence of suicidal ideation was likely underestimated. CONCLUSIONS: Suicidal ideation in HD frequently occurs. Assessment of suicidal ideation is a priority in mutation carriers with a depressed mood and in those using benzodiazepines
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