20 research outputs found

    LYACOLORE: synthetic datasets for current and future Lyman-alpha forest BAO surveys

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    The statistical power of Lyman-α forest Baryon Acoustic Oscillation (BAO) measurements is set to increase significantly in the coming years as new instruments such as the Dark Energy Spectroscopic Instrument deliver progressively more constraining data. Generating mock datasets for such measurements will be important for validating analysis pipelines and evaluating the effects of systematics. With such studies in mind, we present LyaCoLoRe: a package for producing synthetic Lyman-α forest survey datasets for BAO analyses. LyaCoLoRe transforms initial Gaussian random field skewers into skewers of transmitted flux fraction via a number of fast approximations. In this work we explain the methods of producing mock datasets used in LyaCoLoRe, and then measure correlation functions on a suite of realisations of such data. We demonstrate that we are able to recover the correct BAO signal, as well as large-scale bias parameters similar to literature values. Finally, we briefly describe methods to add further astrophysical effects to our skewers—high column density systems and metal absorbers—which act as potential complications for BAO analyses

    The 16th Data Release of the Sloan Digital Sky Surveys: First Release from the APOGEE-2 Southern Survey and Full Release of eBOSS Spectra

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    This paper documents the 16th data release (DR16) from the Sloan Digital Sky Surveys (SDSS), the fourth and penultimate from the fourth phase (SDSS-IV). This is the first release of data from the Southern Hemisphere survey of the Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2); new data from APOGEE-2 North are also included. DR16 is also notable as the final data release for the main cosmological program of the Extended Baryon Oscillation Spectroscopic Survey (eBOSS), and all raw and reduced spectra from that project are released here. DR16 also includes all the data from the Time Domain Spectroscopic Survey and new data from the SPectroscopic IDentification of ERosita Survey programs, both of which were co-observed on eBOSS plates. DR16 has no new data from the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey (or the MaNGA Stellar Library "MaStar"). We also preview future SDSS-V operations (due to start in 2020), and summarize plans for the final SDSS-IV data release (DR17)

    A metal-line strength indicator for damped Lyman alpha (DLA) systems at low signal-to-noise

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    The bias factor of damped Ly α (DLAs) systems, derived from the cross-correlation with the Ly α forest in absorption spectra of the Baryon Oscillation Spectroscopic Survey of SDSS-III, has been used to infer the characteristic mass of DLA host haloes. So far, no dependence of this bias factor with hydrogen column density NH I or other parameters has been detected. With the aim of measuring the dependence of the bias factor on the strength of metal lines, we define the metal strength parameter S, based on optimally combining equivalent widths of 17 metal lines to obtain the highest possible signal-to-noise ratio of S for individual candidate DLAs (defined as having NH I ≄ 1020 cm−2). We present the distribution of metal strength for these DLAs and the dependence of its mean value on NH I and redshift. We search for systematic effects and variations in the catalogue purity by examining the dependence of the S distribution on the spectral signal-to-noise and the estimated error on S. A catalogue of DLAs with measured equivalent widths for the selected 17 metal lines and the value of S are made publicly available, which are used in a separate paper to measure the dependence of the DLA bias factor on the S parameter. The relation of the metal strength on the gas metal abundances and velocity dispersion is complicated by the saturation of metal lines, and remains to be determined in future work

    HuR-targeted agents: An insight into medicinal chemistry, biophysical, computational studies and pharmacological effects on cancer models

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    The Human antigen R (HuR) protein is an RNA-binding protein, ubiquitously expressed in human tissues, that orchestrates target RNA maturation and processing both in the nucleus and in the cytoplasm. A survey of known modulators of the RNA-HuR interactions is followed by a description of its structure and molecular mechanism of action – RRM domains, interactions with RNA, dimerization, binding modes with naturally occurring and synthetic HuR inhibitors. Then, the review focuses on HuR as a validated molecular target in oncology and briefly describes its role in inflammation. Namely, we show ample evidence for the involvement of HuR in the hallmarks and enabling characteristics of cancer, reporting findings from in vitro and in vivo studies; and we provide abundant experimental proofs of a beneficial role for the inhibition of HuR-mRNA interactions through silencing (CRISPR, siRNA) or pharmacological inhibition (small molecule HuR inhibitors)

    Non-embolic outcomes in patients with cardiovascular disease and atrial fibrillation treated with rivaroxaban

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    Aim: It is not well known how comorbidities may change the prognosis of atrial fibrillation (AF) patients. This study was aimed to analyze the impact of cardiovascular disease on this population. Materials & methods: EMIR was a multicenter, prospective study, including 1433 AF patients taking rivaroxaban for ≄6 months. Data were analyzed according to the presence of vascular disease. Results: Coronary artery disease was detected in 16.4%, peripheral artery disease/aortic plaque in 6.7%, vascular disease in 28.3%. Patients with coronary artery disease had higher rates (per 100 patient-years) of major adverse cardiovascular events (2.98 vs 0.71; p < 0.001) and cardiovascular death (1.79 vs 0.41; p = 0.004). Those with vascular disease had higher rates of thromboembolic events (1.47 vs 0.44; p = 0.007), major adverse cardiovascular events (2.03 vs 0.70; p = 0.004), and cardiovascular death (1.24 vs 0.39; p = 0.025). Patients with peripheral artery disease/aortic plaque had similar rates. Conclusion: AF patients with vascular disease have a higher risk of non-embolic outcomes

    LyaCoLoRe: synthetic datasets for current and future Lyman-α forest BAO surveys

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    The statistical power of Lyman-&#x3B1; forest Baryon Acoustic Oscillation (BAO) measurements is set to increase significantly in the coming years as new instruments such as the Dark Energy Spectroscopic Instrument deliver progressively more constraining data. Generating mock datasets for such measurements will be important for validating analysis pipelines and evaluating the effects of systematics. With such studies in mind, we present LyaCoLoRe: A package for producing synthetic Lyman-&#x3B1; forest survey datasets for BAO analyses. LyaCoLoRe transforms initial Gaussian random field skewers into skewers of transmitted flux fraction via a number of fast approximations. In this work we explain the methods of producing mock datasets used in LyaCoLoRe, and then measure correlation functions on a suite of realisations of such data. We demonstrate that we are able to recover the correct BAO signal, as well as large-scale bias parameters similar to literature values. Finally, we briefly describe methods to add further astrophysical effects to our skewers-high column density systems and metal absorbers-which act as potential complications for BAO analyses

    The Completed SDSS-IV Extended Baryon Oscillation Spectroscopic Survey: Baryon Acoustic Oscillations with Ly alpha Forests

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    We present a measurement of baryonic acoustic oscillations (BAOs) from Lyα absorption and quasars at an effective redshift z=2.33z=2.33 using the complete extended Baryonic Oscillation Spectroscopic Survey (eBOSS). The 16th and final eBOSS data release (SDSS DR16) contains all data from eBOSS and its predecessor, the Baryonic Oscillation Spectroscopic Survey (BOSS), providing 210,005 quasars with z q > 2.10 that are used to measure Lyα absorption. We measure the BAO scale both in the autocorrelation of Lyα absorption and in its cross-correlation with 341,468 quasars with redshift z q > 1.77. Apart from the statistical gain from new quasars and deeper observations, the main improvements over previous work come from more accurate modeling of physical and instrumental correlations and the use of new sets of mock data. Combining the BAO measurement from the auto- and cross-correlation yields the constraints of the two ratios DH(z =2.33)/rd=8.99±0.19{D}_{H}(z\,=2.33)/{r}_{d}=8.99\pm 0.19 and DM(z=2.33)/rd=37.5±1.1{D}_{M}(z=2.33)/{r}_{d}=37.5\pm 1.1, where the error bars are statistical. These results are within 1.5σ of the prediction of the flat-ΛCDM cosmology of Planck (2016). The analysis code, picca, the catalog of the flux transmission field measurements, and the Δχ 2 surfaces are publicly available

    The DESI Survey Validation: Results from Visual Inspection of the Quasar Survey Spectra

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    International audienceA key component of the Dark Energy Spectroscopic Instrument (DESI) survey validation (SV) is a detailed visual inspection (VI) of the optical spectroscopic data to quantify key survey metrics. In this paper we present results from VI of the quasar survey using deep coadded SV spectra. We show that the majority (~70%) of the main-survey targets are spectroscopically confirmed as quasars, with ~16% galaxies, ~6% stars, and ~8% low-quality spectra lacking reliable features. A non-negligible fraction of the quasars are misidentified by the standard DESI spectroscopic pipeline but we show that the majority can be recovered using post-pipeline "afterburner" quasar-identification approaches. We combine these "afterburners" with our standard pipeline to create a modified pipeline to improve the overall quasar completeness. At the depth of the main DESI survey both pipelines achieve a good-redshift purity (reliable redshifts measured within 3000 km/s) of ~99%; however, the modified pipeline recovers ~94% of the visually inspected quasars, as compared to just ~86% from the standard pipeline. We demonstrate that both pipelines achieve an overall redshift precision and accuracy of ~100 km/s and ~70 km/s, respectively. We constructed composite spectra to investigate why some quasars are missed by the standard spectroscopic pipeline and find that they are more host-galaxy dominated and/or dust reddened than the standard-pipeline quasars. We also show example spectra to demonstrate the overall diversity of the DESI quasar sample and provide strong-lensing candidates where two targets contribute to a single DESI spectrum

    The Early Data Release of the Dark Energy Spectroscopic Instrument

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    International audienceThe Dark Energy Spectroscopic Instrument (DESI) completed its five-month Survey Validation in May 2021. Spectra of stellar and extragalactic targets from Survey Validation constitute the first major data sample from the DESI survey. This paper describes the public release of those spectra, the catalogs of derived properties, and the intermediate data products. In total, the public release includes good-quality spectral information from 466,447 objects targeted as part of the Milky Way Survey, 428,758 as part of the Bright Galaxy Survey, 227,318 as part of the Luminous Red Galaxy sample, 437,664 as part of the Emission Line Galaxy sample, and 76,079 as part of the Quasar sample. In addition, the release includes spectral information from 137,148 objects that expand the scope beyond the primary samples as part of a series of secondary programs. Here, we describe the spectral data, data quality, data products, Large-Scale Structure science catalogs, access to the data, and references that provide relevant background to using these spectra
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