6,866 research outputs found

    East Asia Researcher Available To Discuss Growing Tension Between North And South Korea

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    ALMA Observations of the Submillimeter Dense Molecular Gas Tracers in the Luminous Type-1 Active Nucleus of NGC 7469

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    We present ALMA Cycle 1 observations of the central kpc region of the luminous type-1 Seyfert galaxy NGC 7469 with unprecedented high resolution (0.5"" ×\times 0.4"" = 165 pc ×\times 132 pc) at submillimeter wavelengths. Utilizing the wide-bandwidth of ALMA, we simultaneously obtained HCN(4-3), HCO+^+(4-3), CS(7-6), and partially CO(3-2) line maps, as well as the 860 μ\mum continuum. The region consists of the central \sim 1"" component and the surrounding starburst ring with a radius of \sim 1.5""-2.5"". Several structures connect these components. Except for CO(3-2), these dense gas tracers are significantly concentrated towards the central \sim 1"", suggesting their suitability to probe the nuclear regions of galaxies. Their spatial distribution resembles well those of centimeter and mid-infrared continuum emissions, but it is anti-correlated with the optical one, indicating the existence of dust obscured star formation. The integrated intensity ratios of HCN(4-3)/HCO+^+(4-3) and HCN(4-3)/CS(7-6) are higher at the AGN position than at the starburst ring, which is consistent to our previous findings (submm-HCN enhancement). However, the HCN(4-3)/HCO+^+(4-3) ratio at the AGN position of NGC 7469 (1.11±\pm0.06) is almost half of the corresponding value of the low-luminosity type-1 Seyfert galaxy NGC 1097 (2.0±\pm0.2), despite the more than two orders of magnitude higher X-ray luminosity of NGC 7469. But the ratio is comparable to that of the close vicinity of the AGN of NGC 1068 (\sim 1.5). Based on these results, we speculate that some other heating mechanisms than X-ray (e.g., mechanical heating due to AGN jet) can contribute significantly for shaping the chemical composition in NGC 1097.Comment: Fixed typos in the title. 15 pages, 8 figures, 4 tables: accepted for publication in ApJ. Comments welcom

    Learning a Physical Activity Classifier for a Low-power Embedded Wrist-located Device

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    This article presents and evaluates a novel algorithm for learning a physical activity classifier for a low-power embedded wrist-located device. The overall system is designed for real-time execution and it is implemented in the commercial low-power System-on-Chips nRF51 and nRF52. Results were obtained using a database composed of 140 users containing more than 340 hours of labeled raw acceleration data. The final precision achieved for the most important classes, (Rest, Walk, and Run), was of 96%, 94%, and 99% and it generalizes to compound activities such as XC skiing or Housework. We conclude with a benchmarking of the system in terms of memory footprint and power consumption.Comment: Submitted to the 2018 IEEE International Conference on Biomedical and Health Informatic

    Two Massive, Low-Luminosity Cores Toward Infrared Dark Clouds

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    This article presents high-resolution interferometric mosaics in the 850 micron waveband of two massive, quiescent infrared dark clouds. The two clouds were chosen based on their likelihood to represent environments preceding the formation of massive stars. The brightest compact sources detected in each cloud have masses of approximately 110 and 60 solar masses with radii < 0.1 pc, implying mean volume densities of approximately 1 million particles per cubic centimeter and mean column densities of about 1 gram per square centimeter. Supplementary data show these cores to be cold and inactive. Low upper limits to their bolometric luminosities and temperatures place them at a very early stage of evolution while current models of massive star formation suggest they have the potential to form massive stars.Comment: 6 pages, 5 figures. Accepted for publication by the Astrophysical Journa

    Coordinates of features on the Galilean satellites

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    Control nets of the four Galilean satellites, established photogrammetrically from pictures taken by the two Voyager spacecraft during their flybys of Jupiter in 1979, are discussed. Coordinates of 504 points on Io, 112 points on Europa, 1547 points on Ganymede, and 439 points on Callisto are listed. Selected points are identified on maps of the satellites. Measurements of these points were made on 234 pictures of Io, 115 pictures of Europa, 282 pictures of Ganymede, and 200 pictures of Callisto. The systems of longitude were defined by craters on Europa, Ganymede, and Callisto. Preliminary solutions are found for the directions of the axes of rotation of the Galilean satellites. Mean radii are determined as 1815 + or - 5 km for Io, 1569 + or - 10 km for Europa, 2631 + or - km for Ganymede, and 2400 + or - 10 km for Callisto

    Adaptive Group Sequential Trials with the Standardized Mean Difference as Effect Size

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    In a thorough and extensive simulation study, we investigate the practical properties of repeated confidence intervals and point estimates for the standardized difference of normal means in adaptive group sequential trials. The theoretical foundations have been described in Hartung and Knapp (2009, 2010). In the simulation study, we consider an adaptive three-stage Pocock (1977)-type design for planning and showing noninferiority and an adaptive five-stage O'Brien-Fleming (1979)-type design for planning and showing superiority

    Study of the radiative decay ϕηγ\phi \to \eta \gamma with CMD-2 detector

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    Using the 1.9pb11.9 pb^{-1} of data collected with the CMD-2 detector at VEPP-2M the decay mode ϕηγ\phi \to \eta \gamma, ηπ+ππ0\eta \to \pi^+\pi^-\pi^0 has been studied. The obtained branching ratio is B(ϕηγ)=(1.18±0.03±0.06)\phi \to \eta \gamma) = (1.18 \pm 0.03 \pm 0.06) %.Comment: 13 pages, 5 figures, LaTex2e, to be published in Phys. Lett.

    Predicted structures of agonist and antagonist bound complexes of adenosine A_3 receptor

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    We used the GEnSeMBLE Monte Carlo method to predict ensemble of the 20 best packings (helix rotations and tilts) based on the neutral total energy (E) from a vast number (10 trillion) of potential packings for each of the four subtypes of the adenosine G protein-coupled receptors (GPCRs), which are involved in many cytoprotective functions. We then used the DarwinDock Monte Carlo methods to predict the binding pose for the human A_3 adenosine receptor (hAA_3R) for subtype selective agonists and antagonists. We found that all four A_3 agonists stabilize the 15th lowest conformation of apo-hAA_3R while also binding strongly to the 1st and 3rd. In contrast the four A_3 antagonists stabilize the 2nd or 3rd lowest conformation. These results show that different ligands can stabilize different GPCR conformations, which will likely affect function, complicating the design of functionally unique ligands. Interestingly all agonists lead to a trans χ1 angle for W6.48 that experiments on other GPCRs associate with G-protein activation while all 20 apo-AA_3R conformations have a W6.48 gauche+ χ1 angle associated experimentally with inactive GPCRs for other systems. Thus docking calculations have identified critical ligand-GPCR structures involved with activation. We found that the predicted binding site for selective agonist Cl-IB-MECA to the predicted structure of hAA_3R shows favorable interactions to three subtype variable residues, I253^(6.58), V169^(EL2), and Q167^(EL2), while the predicted structure for hAA_(2A)R shows weakened to the corresponding amino acids: T256^(6.58), E169^(EL2), and L167^(EL2), explaining the observed subtype selectivity

    The deuterium fractionation of water on solar-system scales in deeply-embedded low-mass protostars

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    (Abridged) The water deuterium fractionation (HDO/H2_2O abundance ratio) has traditionally been used to infer the amount of water brought to Earth by comets. Measuring this ratio in deeply-embedded low-mass protostars makes it possible to probe the critical stage when water is transported from clouds to disks in which icy bodies are formed. We present sub-arcsecond resolution observations of HDO in combination with H218_2^{18}O from the PdBI toward the three low-mass protostars NGC 1333-IRAS 2A, IRAS 4A-NW, and IRAS 4B. The resulting HDO/H2_2O ratio is 7.4±2.1×1047.4\pm2.1\times10^{-4} for IRAS 2A, 19.1±5.4×10419.1\pm5.4\times10^{-4} for IRAS 4A-NW, and 5.9±1.7×1045.9\pm1.7\times10^{-4} for IRAS 4B. Derived ratios agree with radiative transfer models within a factor of 2-4 depending on the source. Our HDO/H2_2O ratios for the inner regions (where T>100T>100 K) of four young protostars are only a factor of 2 higher than those found for pristine, solar system comets. These small differences suggest that little processing of water occurs between the deeply embedded stage and the formation of planetesimals and comets.Comment: 10 pages, 6 figures, accepted for publication in Astronomy and Astrophysic
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