589 research outputs found

    The Horsehead mane: Towards an observational benchmark for chemical models

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    After a discussion about the need for observational benchmark for chemical models, we explain 1) why the Horsehead western edge is well suited to serve as reference for models and 2) the steps we are taking toward this goal. We summarize abundances obtained to date and we show recent results

    Acute Liver Failure in a COVID-19 Patient Without any Preexisting Liver Disease.

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    In December 2019, an outbreak of novel coronavirus started in Wuhan, China, which gradually spread to the entire world. The World Health Organization (WHO) on February 11, 2020, officially announced the name for the disease as coronavirus disease 2019, abbreviated as COVID-19. It is caused by severe respiratory distress syndrome coronavirus 2 (SARS-CoV-2). The WHO declared SARS-CoV-2 as a pandemic on March 11, 2020. SARS-CoV-2 mainly causes fever as well as respiratory symptoms such as cough and shortness of breath. Gastrointestinal/hepatic sequelae such as diarrhea, nausea, vomiting, and elevated liver enzymes have been reported as well. Studies and data so far on coronavirus infections from China, Singapore, and other countries showed that liver enzymes elevation could be seen in 20-50% of cases. More severe disease can correlate with the worsening of liver enzymes. However, acute liver failure in patients with COVID-19 has not been described. Herein we report a case of acute liver failure in an elderly patient with COVID-19 infection who did not have a history of preexisting liver disease

    A Case of Wernicke\u27s Encephalopathy in a Pregnant Woman With a History of Sleeve Gastrectomy.

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    Wernicke\u27s encephalopathy (WE) is a neurological complication of thiamine deficiency characterized by a triad of acute confusion, ataxia, and ophthalmoplegia. Even though it is most common in chronic alcoholism, an increase in prevalence has been reported recently due to the increased popularity of bariatric surgeries. WE is a known neurological complication after gastric bypass surgery but rarely reported after sleeve gastrectomy. We present a unique case of WE in pregnant women four months after sleeve gastrectomy

    A complement to the modern crystallographer's toolbox: Caged gadolinium complexes with versatile binding modes

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    A set of seven caged gadolinium complexes were used as vectors for introducing the chelated Gd3+ ion into protein crystals in order to provide strong anomalous scattering for de novo phasing. The complexes contained multidentate ligand molecules with different functional groups to provide a panel of possible interactions with the protein. An exhaustive crystallographic analysis showed them to be nondisruptive to the diffraction quality of the prepared derivative crystals, and as many as 50% of the derivatives allowed the determination of accurate phases, leading to high-quality experimental electron-density maps. At least two successful derivatives were identified for all tested proteins. Structure refinement showed that the complexes bind to the protein surface or solvent-accessible cavities, involving hydrogen bonds, electrostatic and CH-π interactions, explaining their versatile binding modes. Their high phasing power, complementary binding modes and ease of use make them highly suitable as a heavy-atom screen for high-throughput de novo structure determination, in combination with the SAD method. They can also provide a reliable tool for the development of new methods such as serial femtosecond crystallography. © 2014 International Union of Crystallography.Peer Reviewe

    Can Reflection from Grains Diagnose the Albedo?

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    By radiation transfer models with a realistic power spectra of the projected density distributions, we show that the optical properties of grains are poorly constrained by observations of reflection nebulae. The ISM is known to be hierarchically clumped from a variety of observations (molecules, H I, far-infrared). Our models assume the albedo and phase parameter of the dust, the radial optical depth of the sphere averaged over all directions, and random distributions of the dust within the sphere. The outputs are the stellar extinction, optical depth, and flux of scattered light as seen from various viewing angles. Observations provide the extinction and scattered flux from a particular direction. Hierarchical geometry has a large effect on the flux of scattered light emerging from a nebula for a particular extinction of the exciting star. There is a very large spread in both scattered fluxes and extinctions for any distribution of dust. Consequently, an observed stellar extinction and scattered flux can be fitted by a wide range of albedos. With hierarchical geometry it is not completely safe to determine even relative optical constants from multiwavelength observations of the same reflection nebula. The geometry effectively changes with wavelength as the opacity of the clumps varies. Limits on the implications of observing the same object in various wavelengths are discussed briefly. Henry (2002) uses a recipe to determine the scattered flux from a star with a given extinction. It is claimed to be independent of the geometry. It provides considerably more scattering than our models, probably leading to an underestimate of the grain albedos from the UV Diffuse Galactic Light.Comment: 27 pages, including 7 figures. Accepted by Ap

    PGI12 Mean Annual Cost Of Patients Hospitalized For Chronic Hepatitis C In France: The Hepc-Lone Study

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    Las relaciones laborales marítimas se singularizan por caracteres que han propiciado la necesidad de formular instrumentos que tutelen los derechos de la gente de mar. Entre las singularidades más destacadas está el centro de trabajo: el buque. Su casuística para navegar por las aguas de diversos Estados ha dificultado localizar un punto de conexión que determine la ley aplicable. Ello es vértice para conocer quién debe garantizar la protección social del trabajador, y a su vez, es el instrumento para concretar las obligaciones del armador. Uno de los principios que caracterizan la Seguridad Social es el criterio de la territorialidad. Este criterio es complejo de trasladar a las relaciones laborales marítimas por varios factores, entre ellos: porque el buque no es una extensión del territorio del Estado donde el armador matricula a aquel. El principio de territorialidad, de forma tradicional se ha trasladado a las relaciones laborales con el criterio de la ley del Estado de bandera que da nacionalidad a la nave.The Maritime Labour relations are characterized by characters that have led to the need to develop instruments, which regulate the rights of seafarers. Among the most prominent singularities is the centre of work: the vessel. Their case series for navigating the waters of various States has made it difficult to locate a connection point to determine the applicable law. This is key point to know who should guarantee the social protection of the worker, and it is the instrument to concretize the liability of the shipowner. One of the principles that characterize social security is the criterion of territoriality. This criterion is complex to move the maritime labour relations by several factors: the vessel is not an extension of the territory of the State where the ship-owner has registered it. The principle of territoriality, in the traditional form, has been transferred to the labour relations with the criterion of the law of the flag State which gives nationality to the vesse

    A Spherical Model for "Starless" Cores of Magnetic Molecular Clouds and Dynamical Effects of Dust Grains

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    In the standard picture of isolated star formation, dense ``starless'' cores are formed out of magnetic molecular clouds due to ambipolar diffusion. Under the simplest spherical geometry, I demonstrate that ``starless'' cores formed this way naturally exhibit a large scale inward motion, whose size and speed are comparable to those detected recently by Taffala et al. and Williams et al. in ``starless'' core L1544. My model clouds have a relatively low mass (of order 10 MM_\odot) and low field strength (of order 10 μ\muG) to begin with. They evolve into a density profile with a central plateau surrounded by a power-law envelope, as found previously. The density in the envelope decreases with radius more steeply than those found by Mouschovias and collaborators for the more strongly magnetized, disk-like clouds. At high enough densities, dust grains become dynamically important by greatly enhancing the coupling between magnetic field and the neutral cloud matter. The trapping of magnetic flux associated with the enhanced coupling leads, in the spherical geometry, to a rapid assemblage of mass by the central protostar, which exacerbates the so-called ``luminosity problem'' in star formation.Comment: 27 pages, 4 figures, accepted by Ap

    Gate-induced magneto-oscillation phase anomalies in graphene bilayers

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    The magneto-oscillations in graphene bilayers are studied in the vicinity of the K and K' points of the Brillouin zone within the four-band continuum model ased on the simplest tight-binding approximation involving only the nearest neighbor interactions. The model is employed to construct Landau plots for a variety of carrier concentrations and bias strengths between the graphene planes. The quantum-mechanical and quasiclassical approaches are compared. We found that the quantum magneto-oscillations are only asymptotically periodic and reach the frequencies predicted quasiclassically for high indices of Landau levels. In unbiased bilayers the phase of oscillations is equal to the phase of massive fermions. Anomalous behavior of oscillation phases was found in biased bilayers with broken inversion symmetry. The oscillation frequencies again tend to quasiclassically predicted ones, which are the same for KK and KK', but the quantum approach yields the gate-tunable corrections to oscillation phases, which differ in sign for K and K'. These valley-dependent phase corrections give rise, instead of a single quasiclassical series of oscillations, to two series with the same frequency but shifted in phase.Comment: 8 pages, 8 figure

    Comparison of absolute gain photometric calibration between Planck/HFI and Herschel/SPIRE at 545 and 857 GHz

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    We compare the absolute gain photometric calibration of the Planck/HFI and Herschel/SPIRE instruments on diffuse emission. The absolute calibration of HFI and SPIRE each relies on planet flux measurements and comparison with theoretical far-infrared emission models of planetary atmospheres. We measure the photometric cross calibration between the instruments at two overlapping bands, 545 GHz / 500 μ\mum and 857 GHz / 350 μ\mum. The SPIRE maps used have been processed in the Herschel Interactive Processing Environment (Version 12) and the HFI data are from the 2015 Public Data Release 2. For our study we used 15 large fields observed with SPIRE, which cover a total of about 120 deg^2. We have selected these fields carefully to provide high signal-to-noise ratio, avoid residual systematics in the SPIRE maps, and span a wide range of surface brightness. The HFI maps are bandpass-corrected to match the emission observed by the SPIRE bandpasses. The SPIRE maps are convolved to match the HFI beam and put on a common pixel grid. We measure the cross-calibration relative gain between the instruments using two methods in each field, pixel-to-pixel correlation and angular power spectrum measurements. The SPIRE / HFI relative gains are 1.047 (±\pm 0.0069) and 1.003 (±\pm 0.0080) at 545 and 857 GHz, respectively, indicating very good agreement between the instruments. These relative gains deviate from unity by much less than the uncertainty of the absolute extended emission calibration, which is about 6.4% and 9.5% for HFI and SPIRE, respectively, but the deviations are comparable to the values 1.4% and 5.5% for HFI and SPIRE if the uncertainty from models of the common calibrator can be discounted. Of the 5.5% uncertainty for SPIRE, 4% arises from the uncertainty of the effective beam solid angle, which impacts the adopted SPIRE point source to extended source unit conversion factor (Abridged)Comment: 13 pages, 10 figures; Incorporates revisions in response to referee comments; cross calibration factors unchange

    Dust in an extremely metal-poor galaxy: mid-infrared observations of SBS 0335-052

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    The metal deficient (Z = Z_sun/41) Blue Compact Dwarf Galaxy (BCD) SBS 0335-052 was observed with ISOCAM between 5 and 17 mic. With a L_12mic/L_B ratio of 2.15, the galaxy is unexpectedly bright in the mid-infrared for such a low-metallicity object. The mid-infrared spectrum shows no sign of the Unidentified Infrared Bands, which we interpret as an effect of the destruction of their carriers by the very high UV energy density in SBS 0335-052. The spectral energy distribution (SED) is dominated by a very strong continuum which makes the ionic lines of [SIV] and [NeIII] very weak. From 5 to 17 mic, the SED can be fitted with a grey-body spectrum, modified by an extinction law similar to that observed toward the Galactic Center, with an optical depth of A_V~19-21 mag. Such a large optical depth implies that a large fraction (as much as ~ 75%) of the current star-formation activity in SBS 0335-052 is hidden by dust with a mass between 3x10^3 M_sun and 5x10^5 M_sun. Silicate grains are present as silicate extinction bands at 9.7 and 18 mic can account for the unusual shape of the MIR spectrum of SBS 0335-052. It is remarkable that such a nearly primordial environment contains as much dust as galaxies which are 10 times more metal-rich. If the hidden star formation in SBS 0335-052 is typical of young galaxies at high redshifts, then the cosmic star formation rate derived from UV/optical fluxes would be underestimated.Comment: 13 pages, 4 figures, requires aaspp4.sty, accepted in Ap
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