831 research outputs found

    Peer review in medical journals: beyond quality of reports towards transparency and public scrutiny of the process

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    Published medical research influences health care providers and policy makers, guides patient management, and is based on the peer review process. Peer review should prevent publication of unreliable data and improve study reporting, but there is little evidence that these aims are fully achieved. In the blinded systems, authors and readers do not know the reviewers' identity. Moreover, the reviewers' reports are not made available to readers. Anonymous peer review poses an ethical imbalance toward authors, who are judged by masked referees, and to the medical community and society at large, in case patients suffer the consequences of acceptance of flawed manuscripts or erroneous rejection of important findings. Some general medical journals have adopted an open process, require reviewers to sign their reports, and links online pre-publication histories to accepted articles. This system increases editors' and reviewers' accountability and allows public scrutiny, consenting readers understand on which basis were decisions taken and by whom. Moreover, this gives credit to reviewers for their apparently thankless job, as online availability of signed and scored reports may contribute to researchers' academic curricula. However, the transition from the blind to the open system could pose problems to journals. Reviewers may be more difficult to find, and publishers or medical societies could resist changes that may affect editorial costs and journals' revenues. Nonetheless, also considering the risk of competing interests in the medical field, general and major specialty journals could consider testing the effects of open review on manuscripts regarding studies that may influence clinical practice

    Abolire la Bossi-Fini?

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    Constraining the mass of the planet(s) sculpting a disk cavity. The intriguing case of 2MASS J16042165-2130284

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    The large cavities observed in the dust and gas distributions of transition disks may be explained by planet-disk interactions. At ~145 pc, 2MASS J16042165-2130284 (J1604) is a 5-12 Myr old transitional disk with different gap sizes in the mm- and μ\mum-sized dust distributions (outer edges at ~79 and at ~63 au, respectively). Its 12^{12}CO emission shows a ~30 au cavity. This radial structure suggests that giant planets are sculpting this disk. We aim to constrain the masses and locations of plausible giant planets around J1604. We observed J1604 with the Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) at the Very Large Telescope (VLT), in IRDIFS\_EXT, pupil-stabilized mode, obtaining YJH- band images with the integral field spectrograph (IFS) and K1K2-band images with the Infra-Red Dual-beam Imager and Spectrograph (IRDIS). The dataset was processed exploiting the angular differential imaging (ADI) technique with high-contrast algorithms. Our observations reach a contrast of ΔK,YH\Delta K, YH ~12 mag from 0.15" to 0.80" (~22 to 115 au), but no planet candidate is detected. The disk is directly imaged in scattered light at all bands from Y to K, and it shows a red color. This indicates that the dust particles in the disk surface are mainly ≳0.3 μ\gtrsim0.3\,\mum-sized grains. We confirm the sharp dip/decrement in scattered light in agreement with polarized light observations. Comparing our images with a radiative transfer model we argue that the southern side of the disk is most likely the nearest. This work represents the deepest search yet for companions around J1604. We reach a mass sensitivity of ≳2−3MJup\gtrsim 2-3M_{Jup} from ~22 to ~115 au according to a hot start scenario. We propose that a brown dwarf orbiting inside of ~15 au and additional Jovian planets at larger radii could account for the observed properties of J1604 while explaining our lack of detection.Comment: 10 pages, 7 Figures. Accepted for publication in A&A . Abridged abstrac

    Vitamin D deficiency and infertility : insights from in vitro fertilization cycles

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    Context: Vitamin D deficiency has been proven to affect fertility in mammals, but data in human is less convincing. In particular, data on in vitro fertilization (IVF), an attractive model to draw information on this topic, are sparse and conflicting.Objective: Our objective was to investigate IVF outcome in women with deficient 25-hydroxyvitamin D [25 (OH)D] serum levels (30 ng/mL) had the highest chances of pregnancy.Conclusions: VitaminDis an emerging factor influencing female fertility and IVF outcome. Additional studies are pressingly needed to confirm a causal relationship and to investigate the potential therapeutic benefits of vitamin D supplementation

    Calibration of quasi-static aberrations in exoplanet direct-imaging instruments with a Zernike phase-mask sensor. II. Concept validation with ZELDA on VLT/SPHERE

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    Warm or massive gas giant planets, brown dwarfs, and debris disks around nearby stars are now routinely observed by dedicated high-contrast imaging instruments on large, ground-based observatories. These facilities include extreme adaptive optics (ExAO) and state-of-the-art coronagraphy to achieve unprecedented sensitivities for exoplanet detection and spectral characterization. However, differential aberrations between the ExAO sensing path and the science path represent a critical limitation for the detection of giant planets with a contrast lower than a few 10−610^{-6} at very small separations (<0.3\as) from their host star. In our previous work, we proposed a wavefront sensor based on Zernike phase contrast methods to circumvent this issue and measure these quasi-static aberrations at a nanometric level. We present the design, manufacturing and testing of ZELDA, a prototype that was installed on VLT/SPHERE during its reintegration in Chile. Using the internal light source of the instrument, we performed measurements in the presence of Zernike or Fourier modes introduced with the deformable mirror. Our experimental and simulation results are consistent, confirming the ability of our sensor to measure small aberrations (<50 nm rms) with nanometric accuracy. We then corrected the long-lived non-common path aberrations in SPHERE based on ZELDA measurements. We estimated a contrast gain of 10 in the coronagraphic image at 0.2\as, reaching the raw contrast limit set by the coronagraph in the instrument. The simplicity of the design and its phase reconstruction algorithm makes ZELDA an excellent candidate for the on-line measurements of quasi-static aberrations during the observations. The implementation of a ZELDA-based sensing path on the current and future facilities (ELTs, future space missions) could ease the observation of the cold gaseous or massive rocky planets around nearby stars.Comment: 13 pages, 12 figures, A&A accepted on June 3rd, 2016. v2 after language editin

    The SPHERE data center: a reference for high contrast imaging processing

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    The objective of the SPHERE Data Center is to optimize the scientific return of SPHERE at the VLT, by providing optimized reduction procedures, services to users and publicly available reduced data. This paper describes our motivation, the implementation of the service (partners, infrastructure and developments), services, description of the on-line data, and future developments. The SPHERE Data Center is operational and has already provided reduced data with a good reactivity to many observers. The first public reduced data have been made available in 2017. The SPHERE Data Center is gathering a strong expertise on SPHERE data and is in a very good position to propose new reduced data in the future, as well as improved reduction procedures.Comment: SF2A proceeding

    Molecular line mapping of the giant molecular cloud associated with RCW 106 - II. Column density and dynamical state of the clumps

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    We present a fully sampled C^{18}O (1-0) map towards the southern giant molecular cloud (GMC) associated with the HII region RCW 106, and use it in combination with previous ^{13}CO (1-0) mapping to estimate the gas column density as a function of position and velocity. We find localized regions of significant ^{13}CO optical depth in the northern part of the cloud, with several of the high-opacity clouds in this region likely associated with a limb-brightened shell around the HII region G333.6-0.2. Optical depth corrections broaden the distribution of column densities in the cloud, yielding a log-normal distribution as predicted by simulations of turbulence. Decomposing the ^{13}CO and C^{18}O data cubes into clumps, we find relatively weak correlations between size and linewidth, and a more sensitive dependence of luminosity on size than would be predicted by a constant average column density. The clump mass spectrum has a slope near -1.7, consistent with previous studies. The most massive clumps appear to have gravitational binding energies well in excess of virial equilibrium; we discuss possible explanations, which include magnetic support and neglect of time-varying surface terms in the virial theorem. Unlike molecular clouds as a whole, the clumps within the RCW 106 GMC, while elongated, appear to show random orientations with respect to the Galactic plane.Comment: 17 pages, to appear in MNRA
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