1,998 research outputs found

    Application of Artificial Neural Network to Search for Gravitational-Wave Signals Associated with Short Gamma-Ray Bursts

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    We apply a machine learning algorithm, the artificial neural network, to the search for gravitational-wave signals associated with short gamma-ray bursts. The multi-dimensional samples consisting of data corresponding to the statistical and physical quantities from the coherent search pipeline are fed into the artificial neural network to distinguish simulated gravitational-wave signals from background noise artifacts. Our result shows that the data classification efficiency at a fixed false alarm probability is improved by the artificial neural network in comparison to the conventional detection statistic. Therefore, this algorithm increases the distance at which a gravitational-wave signal could be observed in coincidence with a gamma-ray burst. In order to demonstrate the performance, we also evaluate a few seconds of gravitational-wave data segment using the trained networks and obtain the false alarm probability. We suggest that the artificial neural network can be a complementary method to the conventional detection statistic for identifying gravitational-wave signals related to the short gamma-ray bursts.Comment: 30 pages, 10 figure

    UVB Induces HIF-1α-Dependent TSLP Expression via the JNK and ERK Pathways

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    Thymic stromal lymphopoietin (TSLP) may have a key role in the initiation and maintenance of allergic inflammatory diseases, including atopic dermatitis. The present study revealed that UVB radiation exposure could induce TSLP expression in human keratinocytes and a human skin equivalent model. In addition, we investigated the regulatory mechanism of UVB-induced TSLP expression in keratinocytes. TSLP expression was upregulated by transfection with pcDNA3–hypoxia-inducible factor (HIF)-1α (P402A and P564A), which stably expresses HIF-1α protein. UVB-induced TSLP induction in keratinocytes was suppressed in the treatment of mitogen-activated protein kinase inhibitors or small interfering RNAs against HIF-1α. The results of chromatin immunoprecipitation assays indicate the direct involvement of HIF-1α in UVB-mediated TSLP induction. Taken together, these findings indicate that UVB exposure may increase TSLP expression through a HIF-1α-dependent mechanism via the c-JUN N-terminal kinase and extracellular signal-regulated kinase pathways in human keratinocytes. Our data showed that UVB-induced TSLP might increase secretion of the T-helper type 2–attracting chemokine (c–c motif) ligand 17 by human dendritic cells. The present study suggests an important role of HIF-1α in UVB-mediated immune response in keratinocytes

    The Globular Cluster System of M60 (NGC 4649). II. Kinematics of the Globular Cluster System

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    We present a kinematic analysis of the globular cluster (GC) system in the giant elliptical galaxy (gE) M60 in the Virgo cluster. Using the photometric and spectroscopic database of 121 GCs (83 blue GCs and 38 red GCs), we have investigated the kinematics of the GC system. We have found that the M60 GC system shows a significant overall rotation. The rotation amplitude of the blue GCs is slightly smaller than or similar to that of the red GCs, and their angles of rotation axes are similar. The velocity dispersions about the mean velocity and about the best fit rotation curve for the red GCs are marginally larger than those for the blue GCs. Comparison of observed stellar and GC velocity dispersion profiles with those calculated from the stellar mass profile shows that the mass-to-light ratio should be increased as the galactocentric distance increases, indicating the existence of an extended dark matter halo. The entire sample of GCs in M60 is found to have a tangentially biased velocity ellipsoid unlike the GC systems in other gEs. Two subsamples appear to have different velocity ellipsoids. The blue GC system has a modest tangentially biased velocity ellipsoid, while the red GC system has a modest radially biased or an isotropic velocity ellipsoid. From the comparison of the kinematic properties of the M60 GC system to those of other gEs (M87, M49, NGC 1399, NGC 5128, and NGC 4636), it is found that the velocity dispersion of the blue GC system is similar to or larger than that of the red GC system except for M60, and the rotation of the GC system is not negligible. The entire sample of each GC system shows an isotropic velocity ellipsoid except for M60, while the subsamples show diverse velocity ellipsoids. We discuss the implication of these results for the formation models of the GC system in gEs.Comment: 48 pages, 16 figures. To appear in Ap

    Structural Basis of Impaired Disaggregase Function in the Oxidation-sensitive Skd3 Mutant Causing 3-methylglutaconic Aciduria

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    Mitochondria are critical to cellular and organismal health. To prevent damage, mitochondria have evolved protein quality control machines to survey and maintain the mitochondrial proteome. SKD3, also known as CLPB, is a ring-forming, ATP-fueled protein disaggregase essential for preserving mitochondrial integrity and structure. SKD3 deficiency causes 3-methylglutaconic aciduria type VII (MGCA7) and early death in infants, while mutations in the ATPase domain impair protein disaggregation with the observed loss-of-function correlating with disease severity. How mutations in the non-catalytic N-domain cause disease is unknown. Here, we show that the disease-associated N-domain mutation, Y272C, forms an intramolecular disulfide bond with Cys267 and severely impairs SKD

    High-Throughput Fabrication of Resonant Metamaterials with Ultrasmall Coaxial Apertures via Atomic Layer Lithography

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    We combine atomic layer lithography and glancing-angle ion polishing to create wafer-scale metamaterials composed of dense arrays of ultrasmall coaxial nanocavities in gold films. This new fabrication scheme makes it possible to shrink the diameter and increase the packing density of 2 nm-gap coaxial resonators, an extreme subwavelength structure first manufactured via atomic layer lithography, both by a factor of 100 with respect to previous studies. We demonstrate that the nonpropagating zeroth-order Fabry-PĂ©rot mode, which possesses slow light-like properties at the cutoff resonance, traps infrared light inside 2 nm gaps (gap volume ∌ λ[superscript]3/10[superscript 6]). Notably, the annular gaps cover only 3% or less of the metal surface, while open-area normalized transmission is as high as 1700% at the epsilon-near-zero (ENZ) condition. The resulting energy accumulation alongside extraordinary optical transmission can benefit applications in nonlinear optics, optical trapping, and surface-enhanced spectroscopies. Furthermore, because the resonance wavelength is independent of the cavity length and dramatically red shifts as the gap size is reduced, large-area arrays can be constructed with λresonance ≫ period, making this fabrication method ideal for manufacturing resonant metamaterials.United States. Air Force Office of Scientific Research (Grants FA9550-12-1-0357 and FA9550-11-1-0141

    KMT-2016-BLG-1107: A New Hollywood-Planet Close/Wide Degeneracy

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    We show that microlensing event KMT-2016-BLG-1107 displays a new type of degeneracy between wide-binary and close-binary Hollywood events in which a giant-star source envelops the planetary caustic. The planetary anomaly takes the form of a smooth, two-day "bump" far out on the falling wing of the light curve, which can be interpreted either as the source completely enveloping a minor-image caustic due to a close companion with mass ratio q=0.036q=0.036, or partially enveloping a major-image caustic due to a wide companion with q=0.004q=0.004. The best estimates of the companion masses are both in the planetary regime (3.3−1.8+3.5 Mjup3.3^{+3.5}_{-1.8}\,M_{\rm jup} and 0.090−0.037+0.096 Mjup0.090^{+0.096}_{-0.037}\,M_{\rm jup}) but differ by an even larger factor than the mass ratios due to different inferred host masses. We show that the two solutions can be distinguished by high-resolution imaging at first light on next-generation ("30m") telescopes. We provide analytic guidance to understand the conditions under which this new type of degeneracy can appear.Comment: 23 pages, 7 figures, accepted for publication in A

    KMT-2018-BLG-1990Lb: A Nearby Jovian Planet From A Low-Cadence Microlensing Field

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    We report the discovery and characterization of KMT-2018-BLG-1990Lb, a Jovian planet (mp=0.57−0.25+0.79 MJ)(m_p=0.57_{-0.25}^{+0.79}\,M_J) orbiting a late M dwarf (M=0.14−0.06+0.20 M⊙)(M=0.14_{-0.06}^{+0.20}\,M_\odot), at a distance (D_L=1.23_{-0.43}^{+1.06}\,\kpc), and projected at 2.6±0.62.6\pm 0.6 times the snow line distance, i.e., a_{\rm snow}\equiv 2.7\,\au (M/M_\odot), This is the second Jovian planet discovered by KMTNet in its low cadence (0.4 hr−10.4\,{\rm hr}^{-1}) fields, demonstrating that this population will be well characterized based on survey-only microlensing data.Comment: 24 pages, 7 figures, 4 table
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