625 research outputs found

    EC86-416 Depression : The Common Cold of Mental Health

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    Extension Circular 86-416: Depression: the common cold of mental health. According to this circular taking the viewpoint that depression is a part of living puts the problem in perspective. It gets away from foolish notions that depression is automatically a sign of personal weakness or mental illness

    Precision astrometry of pulsars and other compact radio sources in the globular cluster M15

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    The globular cluster (GC) M15 (NGC 7078) is host to at least eight pulsars and two low mass X-ray binaries (LMXBs), one of which is also visible in the radio regime. Here we present the results of a multi-epoch global very long baseline interferometry (VLBI) campaign aiming at i) measuring the proper motion of the known compact radio sources; ii) finding and classifying thus far undetected compact radio sources in the GC; and iii) detecting a signature of the putative intermediate mass black hole (IMBH) proposed to reside at the core of M15. We measure the sky motion in right ascension (µa) and declination (µd) of the pulsars M15A and M15C and of the LMXB AC211 to be (µa,µd)M15A = (-0.54 ± 0.14,-4.33 ± 0.25) mas yr-1, (µa,µd)M15C = (-0.75 ± 0.09,-3.52 ± 0.13) mas yr-1, and (µa, µd)AC211 = (-0.46 ± 0.08,-4.31 ± 0.20) mas yr-1, respectively. Based on these measurements we estimate the global proper motion of M15 to be (µa, µd) = (-0.58 ± 0.18,-4.05 ± 0.34) mas yr -1. We detect two previously known but unclassified compact sources within our field of view. Our observations indicate that one them is of extragalactic origin while the other one is a foreground source, quite likely an LMXB. The double neutron star system M15C became fainter during the observations, disappeared for one year and is now observable again-an effect possibly caused by geodetic precession. The LMXB AC211 shows a double lobed structure in one of the observations indicative of an outburst during this campaign. With the inclusion of the last two of a total of seven observations we confirm the upper mass limit for a putative IMBH to be M•< 500 M·. © 2014 ESO

    DiFX2: A more flexible, efficient, robust and powerful software correlator

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    Software correlation, where a correlation algorithm written in a high-level language such as C++ is run on commodity computer hardware, has become increasingly attractive for small to medium sized and/or bandwidth constrained radio interferometers. In particular, many long baseline arrays (which typically have fewer than 20 elements and are restricted in observing bandwidth by costly recording hardware and media) have utilized software correlators for rapid, cost-effective correlator upgrades to allow compatibility with new, wider bandwidth recording systems and improve correlator flexibility. The DiFX correlator, made publicly available in 2007, has been a popular choice in such upgrades and is now used for production correlation by a number of observatories and research groups worldwide. Here we describe the evolution in the capabilities of the DiFX correlator over the past three years, including a number of new capabilities, substantial performance improvements, and a large amount of supporting infrastructure to ease use of the code. New capabilities include the ability to correlate a large number of phase centers in a single correlation pass, the extraction of phase calibration tones, correlation of disparate but overlapping sub-bands, the production of rapidly sampled filterbank and kurtosis data at minimal cost, and many more. The latest version of the code is at least 15% faster than the original, and in certain situations many times this value. Finally, we also present detailed test results validating the correctness of the new code.Comment: 28 pages, 9 figures, accepted for publication in PAS

    A Characterization of the ALMA Phasing System at 345 GHz

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    The development of the Atacama Large Millimeter/submillimeter Array (ALMA) phasing system (APS) has allowed ALMA to function as an extraordinarily sensitive station for very long baseline interferometry (VLBI) at frequencies of up to 230 GHz (~1.3 mm). Efforts are now underway to extend use of the APS to 345 GHz (~0.87 mm). Here we report a characterization of APS performance at 345 GHz based on a series of tests carried out between 2015-2021, including a successful global VLBI test campaign conducted in 2018 October in collaboration with the Event Horizon Telescope (EHT).Comment: 22 pages, 11 figures, 7 tables, accepted for publication in PAS

    On the Calibration of Full-polarization 86GHz Global VLBI Observations

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    We report the development of a semi-automatic pipeline for the calibration of 86 GHz full-polarization observations performed with the Global Millimeter-VLBI array (GMVA) and describe the calibration strategy followed in the data reduction. Our calibration pipeline involves non-standard procedures, since VLBI polarimetry at frequencies above 43 GHz is not yet well established. We also present, for the first time, a full-polarization global-VLBI image at 86 GHz (source 3C 345), as an example of the final product of our calibration pipeline, and discuss the effect of instrumental limitations on the fidelity of the polarization images. Our calibration strategy is not exclusive for the GMVA, and could be applied on other VLBI arrays at millimeter wavelengths. The use of this pipeline will allow GMVA observers to get fully-calibrated datasets shortly after the data correlation.Comment: 10 pages, 10 figures. Accepted for publication in A&

    Search for the active ingredients from a 2-aminothiazole DMSO stock solution with antimalarial activity

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    Chemical decomposition of DMSO stock solutions is a common incident that can mislead biological screening campaigns. Here, we share our case study of 2-aminothiazole 1, originating from an antimalarial class that undergoes chemical decomposition in DMSO at room temperature. As previously measured biological activities observed against Plasmodium falciparum NF54 and for the target enzyme Pf IspE were not reproducible for a fresh batch, we tackled the challenge to understand where the activity originated from. Solvent- and temperature-dependent studies using HRMS and NMR spectroscopy to monitor the decomposition led to the isolation and in vitro evaluation of several fractions against Pf IspE. After four days of decomposition, we successfully isolated the oxygenated and dimerised compounds using SFC purification and correlated the observed activities to them. Due to the unstable nature of the two isolates, it is likely that they undergo further decomposition contributing to the overall instability of the compound

    On the Tort of Light Pollution

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    光污染是现代社会的新公害。光污染,在英美被称为“干扰光”,在日本则称其为“光害”,在德国则被视为“不可量物”的一种,而在我国,有学者援用“噪音”的说法,将其称“噪光”。光污染是指因不当使用人为照明或其它设备造成光的入侵而引起的不良影响。对于光污染,根据不同的标准可以作不同的分类。例如根据光污染发生时间的不同,可以将光污染分为昼光光污染和夜光光污染。国际上一般将光污染分成三类,即白亮污染、人工白昼和彩光污染。光污染对环境、生物和人都危害甚巨。 我国现行涉及光污染侵权的立法主要体现在宪法、民法通则、物权法、侵权责任法、环境保护法和地方立法之中。我国现行涉及光污染侵权的立法,无论是中央立法还是地方...Light pollution is a new form of environment pollution in modern society. It was called "interference of light" in Britain and America. It was called "light nuisance" in Japan. In Germany, light pollution is considered to be a kind of "non-amount of matter". Light pollution is due to the improper use of artificial lighting and the adverse effects caused by the invasion of light. According to the d...学位:法律硕士院系专业:法学院法律系_法律硕士(JM)学号:1302009115036

    Targeting the IspD enzyme in the MEP pathway: identification of a novel fragment class

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    Enzymes of the 2-C-methylerythritol-d-erythritol 4-phosphate 2C-methyl-D-erythritol 4-phosphate (MEP) pathway (MEP pathway or non-mevalonate pathway) are responsible for the synthesis of universal precursors of the huge large and structurally diverse family of isoprenoids. This pathway is absent in humans, but present in many pathogenic organisms and plants, making it an attractive source of drug targets. Here, we present a high-throughput screening approach that led to the discovery of a novel fragment hit active against the third enzyme of the MEP pathway, PfIspD. A systematic SAR investigation afforded a novel chemical structure with a balanced activity-stability profile (16). Using a homology model of PfIspD, we proposed a putative binding mode for our newly identified inhibitors that sets the stage for structure-guided optimization

    Targeting the IspD Enzyme in the MEP Pathway: Identification of a Novel Fragment Class

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    The enzymes of the 2-C-methylerythritol-d-erythritol 4-phosphate (MEP) pathway (MEP pathway or non-mevalonate pathway) are responsible for the synthesis of universal precursors of the large and structurally diverse family of isoprenoids. This pathway is absent in humans, but present in many pathogenic organisms and plants, making it an attractive source of drug targets. Here, we present a high-throughput screening approach that led to the discovery of a novel fragment hit active against the third enzyme of the MEP pathway, PfIspD. A systematic SAR investigation afforded a novel chemical structure with a balanced activity–stability profile (16). Using a homology model of PfIspD, we proposed a putative binding mode for our newly identified inhibitors that sets the stage for structure-guided optimization

    Search for the Active Ingredients from a 2-Aminothiazole DMSO Stock Solution with Antimalarial Activity

    Get PDF
    Chemical decomposition of DMSO stock solutions is a common incident that can mislead biological screening campaigns. Here, we share our case study of 2-aminothiazole 1, originating from an antimalarial class that undergoes chemical decomposition in DMSO at room temperature. As previously measured biological activities observed against Plasmodium falciparum NF54 and for the target enzyme PfIspE were not reproducible for a fresh batch, we tackled the challenge to understand where the activity originated from. Solvent- and temperature-dependent studies using HRMS and NMR spectroscopy to monitor the decomposition led to the isolation and in vitro evaluation of several fractions against PfIspE. After four days of decomposition, we successfully isolated the oxygenated and dimerised compounds using SFC purification and correlated the observed activities to them. Due to the unstable nature of the two isolates, it is likely that they undergo further decomposition contributing to the overall instability of the compound
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