2,369 research outputs found

    Strong Cosmic Censorship in Charged de Sitter spacetime with Scalar Field Non-minimally Coupled to Curvature

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    We examine the stability and the strong cosmic censorship in the Reissner-Nordstrom-de Sitter (RN-dS) black hole by investigating the evolution of a scalar field non-minimally coupled to the curvature. We find that when the coupling parameter is negative, the RN-dS black hole experiences instability. The instability disappears when the coupling parameter becomes non-negative. With the increase of the coupling parameter, the violation of the strong cosmic censorship occurs at a larger critical charge ratio. But such an increase of the critical charge is suppressed by the increase of the cosmological constant. Different from the minimal coupling situation, it is possible to accommodate β≥1\beta\ge1 in the near extremal black hole when the scalar field is non-minimally coupled to curvature. The increase of the cosmological constant can allow β≥1\beta\ge1 to be satisfied for even smaller value of the coupling parameter. The existence of β≥1\beta\ge1 implies that the resulting curvature can continuously cross the Cauchy horizon.Comment: 14 pages, 4 figures, 5 table

    Observation of backscattering-immune chiral electromagnetic modes without time reversal breaking

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    A strategy is proposed to realize robust transport in time reversal invariant photonic system. Using numerical simulation and microwave experiment, we demonstrate that a chiral guided mode in the channel of a three-dimensional dielectric woodpile photonic crystal is immune to the scattering of a square patch of metal or dielectric inserted to block the channel. The chirality based robust transport can be realized in nonmagnetic dielectric materials without any external field.Comment: 16 pages, 5 figure

    ElixirNet: Relation-aware Network Architecture Adaptation for Medical Lesion Detection

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    Most advances in medical lesion detection network are limited to subtle modification on the conventional detection network designed for natural images. However, there exists a vast domain gap between medical images and natural images where the medical image detection often suffers from several domain-specific challenges, such as high lesion/background similarity, dominant tiny lesions, and severe class imbalance. Is a hand-crafted detection network tailored for natural image undoubtedly good enough over a discrepant medical lesion domain? Is there more powerful operations, filters, and sub-networks that better fit the medical lesion detection problem to be discovered? In this paper, we introduce a novel ElixirNet that includes three components: 1) TruncatedRPN balances positive and negative data for false positive reduction; 2) Auto-lesion Block is automatically customized for medical images to incorporate relation-aware operations among region proposals, and leads to more suitable and efficient classification and localization. 3) Relation transfer module incorporates the semantic relationship and transfers the relevant contextual information with an interpretable the graph thus alleviates the problem of lack of annotations for all types of lesions. Experiments on DeepLesion and Kits19 prove the effectiveness of ElixirNet, achieving improvement of both sensitivity and precision over FPN with fewer parameters.Comment: 7 pages, 5 figure, AAAI202

    Study on Perfume Stimulating Olfaction with Volatile Oil of Acorus Gramineus for Treatment of the Alzheimer's Disease Rat

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    ObjectiveTo probe into the therapeutic efect of perfume stimulating olfaction with volatile oil of Acorus Gramineus on the Alzheimer's disease (AD) rat.MethodsTotally 50 adult SD rats, male, weighing 300±10 g, were randomly divided into 5 groups, normal group (group A), olfactory nerve severing model group (group B), AD model group (group C), AD model plus perfume stimulation group (group D), AD model olfactory nerve severing plus perfume stimulation group (group E), 10 rats in each group. After perfume stimulation, Morris maze test was conducted for valuating the learning and memory ability; Malondaldehyde (MDA) content, and superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities in the brain, and the brain weight were detected.ResultsCompared with the AD model group, the average escape latency and swimming distance in 6 days were significantly shorter than those in the group A, B, D (P<0.01), with no significant differences between the group C and the group E (P>0.05); Compared with the group A, B and D, MDA content in the group C significantly increased (P<0.01), and SOD and GSH-Px activities significantly decreased (P<0.01), and brain weight/body weight decreased significantly in the group C (P<0.01), with no significant differences between the group C and the group E (P>0.05).ConclusionPerfume stimultating olfaction with volatile oil of Acorus Gramineus can significantly increase the learning-memory ability, decrease MDA content and increase SOD and GSH-Px activities and weight of brain in AD rats

    2,3,4-Trihy­droxy­benzoic acid 0.25-hydrate

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    The asymmetric unit of the title compound, C7H6O5·0.25H2O, contains two mol­ecules of 2,3,4-trihy­droxy­benzoic acid, with similar conformations, and one water mol­ecule which lies on a twofold rotation axis. Both acid mol­ecules are essentially planar [maximum r.m.s deviations = 0.0324 (2) and 0.0542 (3) Å for the two acid molecules]. The mol­ecular conformations are stabilized by intra­molecular O(phenol)—H⋯O(carbox­yl/phenol) inter­actions. A cyclic inter­molecular association is formed between the two acid and one water mol­ecule [graph set R 3 3(12)] involving O—H⋯O hydrogen bonds. The two acid mol­ecules are further linked through a cyclic R 2 2(8) carb­oxy­lic acid hydrogen-bonding association, which together with inter­molecular O—H⋯O hydrogen-bonding inter­actions involving the phenol groups and the water mol­ecule, and weak π–π inter­actions [minimum ring centroid separation = 3.731 (3) Å], give a three-dimensional network
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