New astrometric reductions of the US Naval Observatory CCD Astrograph Catalog (UCAC) all-sky observations were performed from first principles using the TGAS stars in the 8-11 mag range as the ...reference star catalog. Significant improvements in the astrometric solutions were obtained, and the UCAC5 catalog of mean positions at a mean epoch near 2001 was generated. By combining UCAC5 with Gaia DR1 data, new proper motions were obtained for over 107 million stars on the Gaia coordinate system, with typical accuracies of 1-2 mas yr−1 (R = 11-15 mag) and about 5 mas yr−1 at 16th mag. Proper motions of most TGAS stars are improved over their Gaia data and the precision level of TGAS proper motions is extended to many millions more, fainter stars. External comparisons were made using stellar cluster fields and extragalactic sources. The TGAS data allow us to derive the limiting precision of the UCAC x, y data, which is significantly better than1/100 pixel.
UCAC4 is an updated version of UCAC3 with about the same number of stars also covering all-sky. Bugs were fixed, Schmidt plate survey data were avoided, and precise five-band photometry was added for ...about half the stars. Astrograph observations have been supplemented for bright stars by FK6, Hipparcos, and Tycho-2 data to compile a UCAC4 star catalog complete from the brightest stars to about magnitude R = 16. Epoch 1998-2004 positions are obtained from observations with the 20 cm aperture USNO Astrograph's "red lens," equipped with a 4k by 4k CCD. Mean positions and PMs are derived by combining these observations with over 140 ground- and space-based catalogs, including Hipparcos/Tycho and the AC2000.2, as well as unpublished measures of over 5000 plates from other astrographs. These data are supplemented by 2MASS near-IR photometry for about 110 million stars and five-band (B, V, g. r, i) APASS data for over 51 million stars.
Between 1997 and 2004 several observing runs were conducted, mainly with the CTIO 0.9 m, to image International Celestial Reference Frame (ICRF) counterparts (mostly QSOs) in order to determine ...accurate optical positions. Contemporary to these deepCCDimages, the same fields were observed with theU.S.Naval Observatory astrograph in the same bandpass. They provide accurate positions on the Hipparcos/Tycho-2 system for stars in the 10-16 mag range used as reference stars for the deep CCD imaging data. Here we present final optical position results of 413 sources based on reference stars obtained by dedicated astrograph observations that were reduced following two different procedures. These optical positions are compared to radio very long baseline interferometry positions. The current optical system is not perfectly aligned to the ICRF radio system with rigid body rotation angles of 3-5 mas (= 3sigma level) found between them for all three axes. Furthermore, statistically, the optical-radio position differences are found to exceed the total, combined, known errors in the observations. Systematic errors in the optical reference star positions and physical offsets between the centers of optical and radio emissions are both identified as likely causes. A detrimental, astrophysical, random noise component is postulated to be on about the 10 mas level. If confirmed by future observations, this could severely limit the Gaia to ICRF reference frame alignment accuracy to an error of about 0.5 mas per coordinate axis with the current number of sources envisioned to provide the link. A list of 36 ICRF sources without the detection of an optical counterpart to a limiting magnitude of about R = 22 is provided as well.
The third US Naval Observatory (USNO) CCD Astrograph Catalog, UCAC3, was released at the IAU General Assembly on 2009 August 10. It is the first all-sky release in this series and contains just over ...100 million objects, about 95 million of them with proper motions, covering about R = 8-16 mag. Current epoch positions are obtained from the observations with the 20 cm aperture USNO Astrograph's 'red lens,' equipped with a 4k X 4k CCD. Proper motions are derived by combining these observations with over 140 ground- and space-based catalogs, including Hipparcos/Tycho and the AC2000.2, as well as unpublished measures of over 5000 plates from other astrographs. For most of the faint stars in the southern hemisphere, the Yale/San Juan first epoch plates from the Southern Proper Motion (SPM) program (YSJ1) form the basis for proper motions. These data are supplemented by all-sky Schmidt plate survey astrometry and photometry obtained from the SuperCOSMOS project, as well as 2MASS near-IR photometry. Major differences of UCAC3 data as compared with UCAC2 include a completely new raw data reduction with improved control over systematic errors in positions, significantly improved photometry, slightly deeper limiting magnitude, coverage of the north pole region, greater completeness by inclusion of double stars, and weak detections. This of course leads to a catalog which is not as 'clean' as UCAC2 and problem areas are outlined for the user in this paper. The positional accuracy of stars in UCAC3 is about 15-100 mas per coordinate, depending on magnitude, while the errors in proper motions range from 1 to 10 mas yr--1 depending on magnitude and observing history, with a significant improvement over UCAC2 achieved due to the re-reduced SPM data and inclusion of more astrograph plate data unavailable at the time of UCAC2.
ABSTRACT We present an all-sky sample of 1.4 million active galactic nuclei (AGNs) meeting a two-color infrared photometric selection criteria for AGNs as applied to sources from the Wide-field ...Infrared Survey Explorer final catalog release (AllWISE). We assess the spatial distribution and optical properties of our sample and find that the results are consistent with expectations for AGNs. These sources have a mean density of 38 AGNs per square degree on the sky, and their apparent magnitude distribution peaks at g 20, extending to objects as faint as g 26. We test the AGN selection criteria against a large sample of optically identified stars and determine the "leakage" (that is, the probability that a star detected in an optical survey will be misidentified as a quasi-stellar object (QSO) in our sample) rate to be ≤4.0 × 10−5. We conclude that our sample contains almost no optically identified stars (≤0.041%), making this sample highly promising for future celestial reference frame work as it significantly increases the number of all-sky, compact extragalactic objects. We further compare our sample to catalogs of known AGNs/QSOs and find a completeness value of 84% (that is, the probability of correctly identifying a known AGN/QSO is at least 84%) for AGNs brighter than a limiting magnitude of R 19. Our sample includes approximately 1.1 million previously uncataloged AGNs.
The high use of antibiotics in human and veterinary medicine has led to a wide spread of antibiotics and antimicrobial resistance into the environment. In recent years, various studies have shown ...that antibiotic residues, resistant bacteria and resistance genes, occur in aquatic environments and that clinical wastewater seems to be a hot spot for the environmental spread of antibiotic resistance. Here a representative statistical analysis of various sampling points is presented, containing different proportions of clinically influenced wastewater. The statistical analysis contains the calculation of the odds ratios for any combination of antibiotics with resistant bacteria or resistance genes, respectively. The results were screened for an increased probability of detecting resistant bacteria, or resistance genes, with the simultaneous presence of antibiotic residues. Positive associated sets were then compared, with regards to the detected median concentration, at the investigated sampling points. All results show that the sampling points with the highest proportion of clinical wastewater always form a distinct cluster concerning resistance. The results shown in this study lead to the assumption that ciprofloxacin is a good indicator of the presence of multidrug resistant P. aeruginosa and extended spectrum β-lactamase (ESBL)-producing Klebsiella spec., Enterobacter spec. and Citrobacter spec., as it positively relates with both parameters. Furthermore, a precise relationship between carbapenemase genes and meropenem, regarding the respective sampling sites, could be obtained. These results highlight the role of clinical wastewater for the dissemination and development of multidrug resistance.
•Clinically influenced wastewater differs from municipal wastewater (WW).•Statistical associations between antibiotics and resistant bacteria are observed.•Ciprofloxacin seems to be an indicator for the presence of ESBL-producing bacteria.•P. aeruginosa, resistant against 3rd gen. cephalosporins, were mainly in clinical WW.
Objective. Notch signaling pathway is a vital parameter of the mammalian vascular system. In this review, the authors summarize the current knowledge about the impact of the Notch signaling pathway ...in breast cancer progression and the therapeutic role of Notch’s inhibition. Methods. The available literature in MEDLINE, PubMed, and Scopus, regarding the role of the Notch pathway in breast cancer progression was searched for related articles from about 1973 to 2017 including terms such as “Notch,” “Breast Cancer,” and “Angiogenesis.” Results. Notch signaling controls the differentiation of breast epithelial cells during normal development. Studies confirm that the Notch pathway has a major participation in breast cancer progression through overexpression and/or abnormal genetic type expression of the notch receptors and ligands that determine angiogenesis. The cross-talk of Notch and estrogens, the effect of Notch in breast cancer stem cells formation, and the dependable Notch overexpression during breast tumorigenesis have been studied enough and undoubtedly linked to breast cancer development. The already applied therapeutic inhibition of Notch for breast cancer can drastically change the course of the disease. Conclusion. Current data prove that Notch pathway has a major participation and multiple roles during breast tumor progression. Inhibition of Notch receptors and ligands provides innovative therapeutic results and could become the therapy of choice in the next few years, even though further research is needed to reach safe conclusions.
ABSTRACT URAT1 is an observational, astrometric catalog covering most of the δ −15° area and a magnitude range of about R = 3-18.5. Accurate positions (typically 10-30 mas standard error) are given ...for over 228 million objects at a mean epoch around 2013.5. For the over 188 million objects matched with the Two Micron All Sky Survey (2MASS) point-source catalog proper motions (typically 5-7 mas yr-1 standard errors) are provided. These data are supplemented by 2MASS and AAVSO Photometric All-Sky Survey (APASS) photometry. Observations, reductions, and catalog construction are described, together with results from external data verifications. The catalog data are served by CDS, Starsbourg (I/329).
Combined sewer overflows (CSOs) are a major source of surface water pollution and degradation. This is particularly visible where sewage collection with combined sewer and centralized treatment are ...well established, such as in Europe and North America: an overwhelming number of surface water bodies are in insufficient status of ecology, hydrology and physico-chemical parameters. Therefore, several countries have started implementing constructed wetlands (CWs) as mainstream on-spot treatment. This paper summarizes the main design approaches that can be adopted. We identified eight different schemes for the implementation of CSO-CWs, based on our international experience and documented by a literature analysis. The performance review includes conventional water quality parameters, as well as pathogen and emergent contaminant removal. Furthermore, modelling tools for advanced design and for understanding a wide applicability of these green infrastructures are presented. This paper also provides a review on other side benefits offered by the adoption of Nature-Based Solutions for CSO treatment, such as ecosystem services, and the most common issues related to their operation and maintenance. Our analysis has produced a list of key factors for design and operation, all derived from full-scale installations in operation up to more than ten years.
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•Combined sewer overflows (CSOs) convey significant pollutant loads to water bodies.•Constructed wetlands (CWs) are Nature-Based Solutions for CSO pollution control.•Review gives state-of-the-art of CSO-CWs based on research and year-long practice.•CSO-CWs show effective removal of conventional, emerging and pathogenic pollutants.•CSO-CWs can provide other ecosystem services (e.g. flood protection, biodiversity).
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