891 research outputs found

    A statistical approach to identify superluminous supernovae and probe their diversity

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    We investigate the identification of hydrogen-poor superluminous supernovae (SLSNe I) using a photometric analysis, without including an arbitrary magnitude threshold. We assemble a homogeneous sample of previously classified SLSNe I from the literature, and fit their light curves using Gaussian processes. From the fits, we identify four photometric parameters that have a high statistical significance when correlated, and combine them in a parameter space that conveys information on their luminosity and color evolution. This parameter space presents a new definition for SLSNe I, which can be used to analyse existing and future transient datasets. We find that 90% of previously classified SLSNe I meet our new definition. We also examine the evidence for two subclasses of SLSNe I, combining their photometric evolution with spectroscopic information, namely the photospheric velocity and its gradient. A cluster analysis reveals the presence of two distinct groups. `Fast' SLSNe show fast light curves and color evolution, large velocities, and a large velocity gradient. `Slow' SLSNe show slow light curve and color evolution, small expansion velocities, and an almost non-existent velocity gradient. Finally, we discuss the impact of our analyses in the understanding of the powering engine of SLSNe, and their implementation as cosmological probes in current and future surveys.Comment: 16 pages, 9 figures, accepted by ApJ on 23/01/201

    Sol–gel-entrapped pH indicator for monitoring pH variations in cementitious materials

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    Sensors for pH evaluation of concrete were made by a sol–gel process with alizarin yellow as pH indicator. The optical absorbance was measured with a visible spectrophotometer coupled with optical fibers. Results showed that the sensors had good reversibility, reproducibility, and fast response time

    Moderately Luminous type II Supernovae

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    Core-collapse Supernovae (CC-SNe) descend from progenitors more massive than about 8 Msun. Because of the young age of the progenitors, the ejecta may eventually interact with the circumstellar medium (CSM) via highly energetic processes detectable in the radio, X-ray, ultraviolet (UV) and, sometimes, in the optical domains. In this paper we present ultraviolet, optical and near infrared observations of five type II SNe, namely SNe 2009dd, 2007pk, 2010aj, 1995ad, and 1996W. Together with few other SNe they form a group of moderately luminous type II events. We collected photometry and spectroscopy with several telescopes in order to construct well-sampled light curves and spectral evolutions from the photospheric to the nebular phases. Both photometry and spectroscopy indicate a degree of heterogeneity in this sample. The light curves have luminous peak magnitudes (−16.95<MB<−18.70-16.95<M_{B}<-18.70). The ejected masses of ^56\ni for three SNe span a wide range of values (2.8×10−22.8\times10^{-2}Msun<<M(\ni)<1.4×10−1<1.4\times10^{-1}Msun), while for a fourth (SN2010aj) we could determine a stringent upper limit (7×10−37\times10^{-3}Msun). Clues of interaction, such as the presence of high velocity (HV) features of the Balmer lines, are visible in the photospheric spectra of SNe 2009dd and 1996W. For SN2007pk we observe a spectral transition from a type IIn to a standard type II SN. Modelling the observations of SNe 2009dd, 2010aj and 1995ad with radiation hydrodynamics codes, we infer kinetic plus thermal energies of about 0.2-0.5 foe, initial radii of 2-5×1013\times10^{13} cm and ejected masses of ∌\sim5.0-9.5 Msun. These values suggest moderate-mass, super-asymptotic giant branch (SAGB) or red super-giants (RSG) stars as SN precursors, in analogy with other luminous type IIP SNe 2007od and 2009bw.Comment: 28 pages, 27 fig, accepted by A&A, 3 pages of online material, abstract abridged. revised significantly with respect to the previous versio

    Advanced 3D “Modeling” and “Printing” for the Surgical Planning of a Successful Case of Thoraco-Omphalopagus Conjoined Twins Separation

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    The surgical separation of two Conjoined Twins is a particularly complex operation. Surgical times are particularly long and post-operative complications are very frequent in this type of procedure. We report a clinical case of surgical separation of two thoraco-omphalopagus conjoined twins in which, thanks to the use of (3D) three dimensional technologies, we were able to significantly reduce operative times and improve clinical outcomes

    The Type IIP SN 2007od in UGC 12846: from a bright maximum to dust formation in the nebular phase

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    Ultraviolet (UV), optical and near infrared (NIR) observations of the type IIP supernova (SN) 2007od are presented, covering from the maximum light to the late phase, allowing to investigate in detail different physical phenomena in the expanding ejecta. These data turn this object into one of the most peculiar IIP ever studied. The early light curve of SN 2007od is similar to that of a bright IIPs with a short plateau, a bright peak (MV = -18 mag), but a very faint optical light curve at late time. However, with the inclusion of mid infrared (MIR) observations during the radioactive decay we have estimate a M(56Ni) ~ 2\times10^-2 M\odot. Modeling the bolometric light curve, ejecta expansion velocities and black-body temperature, we estimate a total ejected mass was 5 - 7.5 M\odot with a kinetic energy of at least 0.5 \times 10^51 erg. The early spectra reveal a boxy H{\alpha} profile and high velocities features of the Balmer series that suggest interaction between the ejecta and a close circum-stellar matter (CSM). SN 2007od may be, therefore, an intermediate case between a Type IIn SN and a typical Type IIP SN. Also late spectra show a clear evidence of CSM and the presence of dust formed inside the ejecta. The episodes of mass loss short before explosion, the bright plateau, along with the relatively small amount of 56Ni and the faint [O I] observed in the nebular spectra are consistent with a super-asympthotic giant branch (super-AGB) progenitor (M~9.7 - 11 M\odot).Comment: V2, some test added and three figures changed from the first version. 21 pages, 18 figures, accepted for publication in MNRAS on May 24, 201

    Supernova 2012ec: Identification of the progenitor and early monitoring with PESSTO

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    We present the identification of the progenitor of the Type IIP SN 2012ec in archival pre-explosion HST WFPC2 and ACS/WFC F814W images. The properties of the progenitor are further constrained by non-detections in pre-explosion WFPC2 F450W and F606W images. We report a series of early photometric and spectroscopic observations of SN 2012ec. The r'-band light curve shows a plateau with M(r')=-17.0. The early spectrum is similar to the Type IIP SN 1999em, with the expansion velocity measured at Halpha absorption minimum of -11,700 km/s (at 1 day post-discovery). The photometric and spectroscopic evolution of SN 2012ec shows it to be a Type IIP SN, discovered only a few days post-explosion (<6d). We derive a luminosity for the progenitor, in comparison with MARCS model SEDs, of log L/Lsun = 5.15+/-0.19, from which we infer an initial mass range of 14-22Msun. This is the first SN with an identified progenitor to be followed by the Public ESO Spectroscopic Survey of Transient Objects (PESSTO).Comment: 6 pages, 3 figures, MNRAS accepte

    SURGERY IN PATIENTS WITH TESTICULAR MALIGNANT GERM CELL TUMORS: COMPLIANCE TO SURGICAL GUIDELINES AND RESULTS IN THE ITALIAN COOPERATIVE STUDY

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    Purpose: Surgery represents a main and often the only treatment in patients with testicular Malignant Germ Cell Tumors (MGCT). We analyzed the compliance to surgical guidelines and the results in a series of patients with testicular MGCT -/+ retroperitoneal node involvement, without distant metastases. Method: 42 patients, observed in 15 Centers were enrolled in the Italian Cooperative Study on MGCT (January2004–December2010). 14/42 were younger than 2 y. of age, 28/42 between 13–18 y. Treatment was delivered according to COG-Staging-System: St.I patients (complete excision with inguinal orchifunicolectomy+decrease of markers, +hemiscrotectomy if scrotal involvement) did not receive further treatment; St.II patients (scrotal involvement after hemiscrotectomy and/or retroperitoneal node (RPN) enlargement:2 cm) had RPN Dissection if residuals were suspected after PEBx3or4. Results: St.I: 26 patients. 3/26 had a scrotal approach due to suspected testicular torsion: 1/3 underwent hemiscrotectomy, 2 did not receive further therapy after decrease of alphaFP, due to patient’s or physician’s decision respectively. 3/26 were successfully treated for RPN relapse, occurred at 3,6,9 months after adequate surgery (2 adolescents, 1 infant). St.II: in 4 patients CTwas delivered due to slight enlargement of RPN (+persistent alphaFP in 1). St.III: 12 patients received CT and RPND (bilateral in 1). Histology was negative in 11/12. All patients are alive without disease, 39 in 1stCR, 3 in 2ndCR (f.u 9–86 m.:med.48). 1 St.1 patient suffered from postoperative scrotal hematoma. Among patients younger than 2 y, 10/14 had a pure YST, 12/14 had St.I disease; among those between 13–18 y, 27/28 had a mixed histology, 14/28 were St.II or St.III. In 3 adolescents a testicular prosthesis was positioned during primary operation. Conclusion: Outcome was excellent. Regional relapses, observed only in St.I patients, were cured. Surgical guidelines were followed in 40/42 cases. Scrotal approach did not worsen the outcome of patients who did not receive further treatment
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