Rotational and Rotational-Vibrational Raman Spectroscopy of Air to Characterize Astronomical Spectrographs

Raman scattering enables unforeseen uses for the laser guide-star system of the Very Large Telescope. Here, we present the observation of one up-link sodium laser beam acquired with the ESPRESSO spectrograph at a resolution λ /Δ λ ˜140 000 . In 900 s on source, we detect the pure rotational Raman lines of 16O2, 14N2, and 14N 15N (tentatively) up to rotational quantum numbers J of 27, 24, and 9, respectively. We detect the 16O2 fine-structure lines induced by the interaction of the electronic spin S and end-over-end rotational angular momentum N in the electronic ground state of this molecule up to N =9 . The same spectrum also reveals the ν1 ←0 rotational-vibrational Q-branch for 16O2 and 14N2 14. These observations demonstrate the potential of using laser guide-star systems as accurate calibration sources for characterizing new astronomical spectrographs

XQ-100: A legacy survey of one hundred 3.5 72 z 72 4.5 quasars observed with VLT/X-shooter

We describe the execution and data reduction of the European Southern Observatory Large Programme "Quasars and their absorption lines: a legacy survey of the high-redshift Universe with VLT/X-shooter" (hereafter "XQ-100"). XQ-100 has produced and made publicly available a homogeneous and high-quality sample of echelle spectra of 100 quasars (QSOs) at redshifts z 43 3.5-4.5 observed with full spectral coverage from 315 to 2500 nm at a resolving power ranging from R \u303. 4000 to 7000, depending on wavelength. The median signal-to-noise ratios are 33, 25 and 43, as measured at rest-frame wavelengths 1700, 3000 and 3600 \uc5, respectively. This paper provides future users of XQ-100 data with the basic statistics of the survey, along with details of target selection, data acquisition and data reduction. The paper accompanies the public release of all data products, including 100 reduced spectra. XQ-100 is the largest spectroscopic survey to date of high-redshift QSOs with simultaneous rest-frame UV/optical coverage, and as such enables a wide range of extragalactic research, from cosmology and galaxy evolution to AGN astrophysics. \ua9 2016 ESO

Nightside condensation of iron in an ultra-hot giant exoplanet

Ultra-hot giant exoplanets receive thousands of times Earth's insolation. Their high-temperature atmospheres (>2,000 K) are ideal laboratories for studying extreme planetary climates and chemistry. Daysides are predicted to be cloud-free, dominated by atomic species and substantially hotter than nightsides. Atoms are expected to recombine into molecules over the nightside, resulting in different day-night chemistry. While metallic elements and a large temperature contrast have been observed, no chemical gradient has been measured across the surface of such an exoplanet. Different atmospheric chemistry between the day-to-night ("evening") and night-to-day ("morning") terminators could, however, be revealed as an asymmetric absorption signature during transit. Here, we report the detection of an asymmetric atmospheric signature in the ultra-hot exoplanet WASP-76b. We spectrally and temporally resolve this signature thanks to the combination of high-dispersion spectroscopy with a large photon-collecting area. The absorption signal, attributed to neutral iron, is blueshifted by -11+/-0.7 km s-1 on the trailing limb, which can be explained by a combination of planetary rotation and wind blowing from the hot dayside. In contrast, no signal arises from the nightside close to the morning terminator, showing that atomic iron is not absorbing starlight there. Iron must thus condense during its journey across the nightside.Comment: Published in Nature (Accepted on 24 January 2020.) 33 pages, 11 figures, 3 table

Hepatitis B virus reactivation after heart transplant: Incidence and clinical impact

Background Occult hepatitis B infection consists of persistence of HBV genomes in hepatocytes,absence of serum HBsAg, low/undetectable serum HBVDNA. Reactivation of HBV infection may occur during immunosuppression, but few data are available in heart transplant. Objectives We followed-up heart recipients with or without markers of previous HBV infection,evaluating prevalence of HBV markers, incidence of HBV reactivation and its virological and clinical features. Study design Heart failure patients listed for heart transplant (2007â2013) were screened for current or past HBV infection. Transplanted patients with past HBV infection (anti-HBc+/±anti-HBs+/HBVDNAâ) were followed up as cases, and an equal number of HBV negative patients as controls. Virological reactivation was detected by standard real-time and home-made highly sensitive PCR (surface/core HBVDNA regions). Clinical status and progression were assessed by liver histology, ultrasound or elastography. Results 67 patients underwent heart transplant, including 4 (5.9%) HBsAg+ subjects. Cases were 11/67 (16.4%). During a median follow-up of 30 months, only one of these 11 patients presented viral reactivation (HBVDNA 209 IU/mL) at month 22, and started antiviral treatment. Four other recipients showed virological events of uncertain significance (sensitive PCR-only intermittently positive). Clinical signs of liver disease were observed in only one case at the last follow-up. A nonsignificant difference in survival was observed between cases and all other heart recipients without prior HBV contact (death rate 5/11 vs 15/52, respectively; p = 0.097). Conclusions HBV genotypic reactivation in HBsAgâ/anti-HBc+/HBVDNAâ heart recipients is uncommon. Virological events of uncertain significance occur more frequently; their clinical impact seems to be negligible

Clinical significance of hyperhomocysteinemia in infective endocarditis A case-control study

Blood coagulation plays a key role in the pathogenesis of infective endocarditis (IE). Conditions associated with thrombophilia could enhance IE vegetation formation and promote embolic complications. In this study, we assessed prevalence, correlates, and clinical consequences of hyper-homocysteinemia (h-Hcy) in IE. Homocysteine (Hcy) plasma levels were studied in 246 IE patients and 258 valvular heart disease (VHD) patients, as well as in 106 healthy controls. IE patients showed Hcy levels comparable to VHD patients (14.9 [3-81] vs 16 [5-50] mmol/L, respectively; P=0.08). H-Hcy was observed in 48.8% of IE patients and 55.8% of VHD (P=0.13). Vegetation size and major embolic complications were not related to Hcy levels. IE patients with h-Hcy had a higher prevalence of chronic kidney disease and a higher 1-year mortality (19.6% vs 9.9% in those without h-Hcy; OR 2.21 [1.00-4.89], P=0.05). However, at logistic regression analysis, h-Hcy was not an independent predictor of 1-year mortality (OR 1.87 [95% CI 0.8-4.2]; P=0.13). Our data suggest h-Hcy in IE is common, is related to a worse renal function, and may be a marker of cardiac dysfunction rather than infection. H-Hcy does not appear to favor IE vegetation formation or its symptomatic embolic complications

Viability of pegIFNα-RBV for CHC in the direct acting antiviral era: a practical algorithm between efficacy and cost containment

<p>The classical pegylated interferon α (peg-IFNα) and ribavirin (RBV) treatment of chronic hepatitis C (CHC) is progressively being replaced by new direct acting antivirals, whose costs remain a major barrier to widespread use. Using baseline data and viral kinetics, we developed a predictive algorithm to allocate to DAA patients who are not going to respond to peg-IFNα/RBV. This prospective study evaluated 205 CHC patients treated with peg-IFNα/RBV. HCVRNA kinetics during the initial 3 days of therapy and baseline variables including age, genotype, fibrosis and ALTs were used to construct a prediction rule in terms of sustained virological response (SVR). One hundred and twenty-one patients achieved an SVR (59%). Variables independently associated with SVR were HCVRNA, ALT, glycaemia, viral genotype, and fibrosis. The decline of viremia from baseline to 48/72 h was significantly different in SVR compared to non-SVR patients (2.2 vs. 0.65 log10 IU/mL; <i>p</i> < 0.001), and was influenced by viral genotype, levels of ALT, stage of fibrosis and IL28B polymorphism. In genotype 1, HCVRNA decline <0.8 logs had a negative predictive value of 90%, and in genotype 2, HCVRNA decline >1.2 logs had a positive predictive value of 92%. A combination of HCVRNA kinetics and a score based on pre-treatment parameters was highly accurate in predicting SVR in most patients. Outcome of peg-IFNα/RBV treatment may be predicted combining evaluation of baseline variables and HCVRNA kinetics. This allows to individualize treatment, reserving newer and more expensive DAAs to CHC patients who are in most need of them.</p

ESPRESSO highlights the binary nature of the ultra-metal-poor giant HE 0107-5240

Context. The vast majority of the known stars of ultra low metallicity ([Fe=H] >-4:5) are known to be enhanced in carbon, and belong to the 'low-carbon band' (A(C) = log(C=H) + 12 7:6). It is generally, although not universally, accepted that this peculiar chemical composition reflects the chemical composition of the gas cloud out of which these stars were formed. The first ultra-metalpoor star discovered, HE 0107-5240, is also enhanced in carbon and belongs to the 'low-carbon band'. It has recently been claimed to be a long-period binary, based on radial velocity measurements. It has also been claimed that this binarity may explain its peculiar composition as being due to mass transfer from a former AGB companion. Theoretically, low-mass ratios in binary systems are much more favoured amongst Pop III stars than they are amongst solar-metallicity stars. Any constraint on the mass ratio of a system of such low metallicity would shed light on the star formation mechanisms in this metallicity regime. Aims.We acquired one high precision spectrum withESPRESSO in order to check the reality of the radial velocity variations. In addition we analysed all the spectra of this star in the ESO archive obtained with UVES to have a set of homogenously measured radial velocities. Methods. The radial velocities were measured using cross correlation against a synthetic spectrum template. Due to the weakness of metallic lines in this star, the signal comes only from the CH molecular lines of the G-band. Results. The measurement obtained in 2018 from an ESPRESSO spectrum demonstrates unambiguously that the radial velocity of HE 0107-5240 has increased from 2001 to 2018. Closer inspection of the measurements based on UVES spectra in the interval 2001-2006 show that there is a 96% probability that the radial velocity correlates with time, hence the radial velocity variations can already be suspected from the UVES spectra alone. Conclusions.We confirm the earlier claims of radial velocity variations in HE0107-5240. The simplest explanation of such variations is that the star is indeed in a binary system with a long period. The nature of the companion is unconstrained and we consider it is equally probable that it is an unevolved companion or a white dwarf. Continued monitoring of the radial velocities of this star is strongly encouraged.With funding from the Spanish government through the "María de Maeztu Unit of Excellence" accreditation (MDM-2017-0737