243 research outputs found

    Quasi Anomalous Knowledge: Searching for new physics with embedded knowledge

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    Discoveries of new phenomena often involve a dedicated search for a hypothetical physics signature. Recently, novel deep learning techniques have emerged for anomaly detection in the absence of a signal prior. However, by ignoring signal priors, the sensitivity of these approaches is significantly reduced. We present a new strategy dubbed Quasi Anomalous Knowledge (QUAK), whereby we introduce alternative signal priors that capture some of the salient features of new physics signatures, allowing for the recovery of sensitivity even when the alternative signal is incorrect. This approach can be applied to a broad range of physics models and neural network architectures. In this paper, we apply QUAK to anomaly detection of new physics events at the CERN Large Hadron Collider utilizing variational autoencoders with normalizing flow.Comment: 25 pages, 9 figure

    Design of 6U Nanosatellites in Formation Flying for the Laser Crosslink Mission

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    With a recent growth in the volume of spaceborne data, free space optical (FSO) or laser communication systems are attracting attention, as they can enable super-high data rates faster than 1 Gbps. The Very high-speed Inter-satellite link Systems using Infrared Optical terminal and Nanosatellite (VISION) is a technical demonstration mission to establish and validate laser crosslink systems using two 6U nanosatellites in formation flying. The final goal is to achieve a Gbps-level data rate at a distance of thousands of kilometers. To establish space-to-space laser communication, the payload optical axes of each satellite should be precisely aligned during the crosslink. The payload is the laser communication terminal (LCT) including the deployable space telescope (DST), which improves optical link performances. The 6U nanosatellite bus is designed with commercial off-the shelf-(COTS) components for agile systems development. For precise formation flying, the bus is equipped a with relative navigation system with a GNSS receiver and RF crosslink, star tracker, 3-axis reaction wheels (RWs), and propulsion system. This proposed concept of the laser crosslink systems will contribute to the construction of the LEO communication constellation with high speed and secure links in future

    Aseptic Endocarditis in Behçet's Disease Presenting as Tricuspid Valve Stenosis

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    Aseptic endocarditis is an uncommon complication of Behçet's disease (BD). We describe a rare case of a 39-year-old female who had BD with aseptic endocarditis of the tricuspid valve (TV) presenting as tricuspid stenosis. She was diagnosed with BD four years ago. The mucocutaneous lesions were well-controlled with colchicine and short courses of corticosteroids. She remained free of signs and symptoms of BD for one year without any medication. Three months before admission, she gradually developed dyspnea on exertion and peripheral edema. Echocardiography revealed dilated right atrium and markedly thickened TV with severe stenosis. TV replacement was performed. Pathologic examination of the valve showed fibrinoid necrotic material and inflammatory cell infiltration. Blood cultures and cultures of the excised valve were negative for microorganisms

    Regulating the surface of anion-doped TiO2 nanorods by hydrogen annealing for superior photoelectrochemical water oxidation

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    Dedications to achieve the highly efficient metal oxide semiconductor for the photoelectrochemical water splitting system have been persisted to utilize the TiO2 as the promising photoanode material. Herein, we report notable progress for nanostructured TiO2 photoanodes using facile sequential one-pot hydrothermal synthesis and annealing in hydrogen. A photocurrent density of 3.04 mA·cm−2 at 1.23 V vs. reversible hydrogen electrode was achieved in TiO2 nanorod arrays annealed in hydrogen ambient, which is approximately 4.25 times higher than that of pristine TiO2 annealed in ambient air. 79.2% of incident photon-to-current efficiency at 380 nm wavelength demonstrates the prominence of the material at the near-UV spectral range region and 100 h chronoamperometric test exhibits the stability of the photoanode. Detailed studies regarding crystallinity, bandgap, and elemental analysis provide the importance of the optimized annealing condition for the TiO2-based photoanodes. Water contact angle measurement displays the effect of hydrogen annealing on the hydrophilicity of the material. This study clearly demonstrates the marked improvement using the optimized hydrogen annealing, providing the promising methodologies for eco-friendly mass production of water splitting photoelectrodes.The authors gratefully acknowledge the fnancial support from the Creative, Material Discovery Program (2016M3D1A1027666, 2017M3D1A1040834, 2018M3D1A1058793) through the National Research Foundation of Korea funded by Ministry of Science and ICT, the Basic Research Laboratory Program through an NRF grant funded by the Korean Ministry of Science, ICT and Future Planning (2021R1A4A302787811), the KRISS (Korea Research Institute of Standards and Science) MPI Lab. Program and the National Research Foundation of Korea (NRF) grant funded by the Korea Government MSIT (2021R1C1C2006142), and Nuclear Energy R&D Program(2020M2D8A206983012). The Inter-University Semiconductor Research Center and Institute of Engineering Research at Seoul National University provided research facilities for this work

    Association of Plasma Levels of Resistin with Subcutaneous Fat Mass and Markers of Inflammation but not with Metabolic Determinants or Insulin Resistance

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    The aim of the present study was to investigate the relationship of plasma resistin levels with determinants of the metabolic syndrome (MetS) and anthropometric parameters in healthy Korean subjects. Plasma resistin levels were determined in 276 subjects. In subjects with MetS, the plasma resistin levels were not significantly increased compared to those without MetS (8.3±4.3 ng/mL vs. 8.5±3.6 ng/mL, respectively, P=0.84). In addition, the plasma resistin levels were not correlated with the body mass index, the waist circumference, homeostasis model assessment-insulin resistance (HOMA-IR), fasting plasma glucose or insulin levels. However, the plasma resistin levels were positively correlated with the abdominal subcutaneous fat (r=0.18, P<0.01) in all subjects and correlated with TNF α(r=-0.16, P<0.05) and hsCRP (r=0.15, P<0.05) in subjects without MetS but not with MetS. With multiple linear regression analysis, these linear associations remained to be significant. The results of this study show that plasma resistin levels in humans were not associated with markers of insulin resistance, obesity or other determinants of the MetS
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