195 research outputs found

    Effective Interaction of Electroweak-Interacting Dark Matter with Higgs Boson and Its Phenomenology

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    We study phenomenology of electroweak-interacting fermionic dark matter (DM) with a mass of O(100)\mathcal{O}(100) GeV. Constructing the effective Lagrangian that describes the interactions between the Higgs boson and the SU(2)L_L isospin multiplet fermion, we evaluate the electric dipole moment (EDM) of electron, the signal strength of Higgs boson decay to two photons and the spin-independent elastic-scattering cross section with proton. As representative cases, we consider the SU(2)L_L triplet fermions with zero/nonzero hypercharges and SU(2)L_L doublet fermion. It is found that the electron EDM gives stringent constraints on those model parameter spaces. In the cases of the triplet fermion with zero hypercharge and the doublet fermion, the Higgs signal strength does not deviate from the standard model prediction by more than a few % once the current DM direct detection constraint is taken into account, even if the CP violation is suppressed. On the contrary, O(10\mathcal{O}(10-20)20) % deviation may occur in the case of the triplet fermion with nonzero hypercharge. Our representative scenarios may be tested by the future experiments.Comment: 13 pages, 5 figures. Version accepted for publication in Phys. Lett.

    Discriminating DRDoS Packets using Time Interval Analysis

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    Distributed Reflection Denial of Service (DRDoS) attack is one of the critical security threats. As the attack generates unidirectional traffic, it is not easy for the targets of the attack to protect themselves. To mitigate the attack, we need a defense mechanism installed at backbone networks, i.e., detecting and blocking the attack traffic before they reach to the destinations. A conventional approach is to monitor the traffic volume of the attack, i.e., an attack is detected if the observed traffic volume exceeds a certain threshold. However, such a simple approach may not work when an attacker adjusts the traffic volume to evade the detection. This paper proposes a novel method that can detect the DRDoS attacks accurately. The key idea is to leverage the characteristics of time intervals between the packets. We make use of the K-means clustering algorithm to find the best threshold values used to distinguish packets associated with DRDoS attacks. We implement the proposed algorithm into an equipment at a data center and demonstrate that our approach attains high accuracy

    Cascading Geological Hazards and Risks of the 2018 Sulawesi Indonesia Earthquake and Sensitivity Analysis of Tsunami Inundation Simulations

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    Multiple cascading hazards triggered by the 2018 Sulawesi, Indonesia, earthquake caused various compounding consequences. A major strike-slip fault movement with along-dip components resulted in intense ground shaking, liquefaction and lateral spreading, large-scale mudflows, and tsunamis. This paper presents observations of such multi-hazard effects on buildings and infrastructure in areas along Palu Bay, based on field reconnaissance work, and discusses the main causes of the disaster by focusing upon the combined effects of the cascading geological hazards. To evaluate the tsunami risk potential of the strike-slip event, tsunami simulations for the 2018 Sulawesi earthquake are performed by considering different model settings for spatial earthquake slip distribution, rake angle, astronomical tidal effect, and co-seismic ground deformation. The numerical results indicate that the co-seismic rupture of a moment magnitude 7.5 strike-slip earthquake, having notable dip components can generate damaging tsunami waves at coastal locations of Palu Bay. The conclusion has important implications for future tsunami hazard assessments in active seismic regions where major fault systems cut across a bay or into the sea

    An origin of good electrical conduction in La 4

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    We have prepared a set of polycrystalline samples of the metallic copper oxide La4BaCu5−xCoxO13+δ (0 ≤ x ≤ 0.35) and have measured the resistivity from 4 to 800 K. All the resistivities show metallic temperature dependence with a small magnitude less than 2 mΩ cm at 800 K, indicating that the metallic conduction is robust against impurities. The robust metallic conduction further suggests that this class of oxide is a promising candidate for electrical leads at high temperature, which might replace platinum. A detailed measurement and analysis on the Hall resistivity have revealed that at least two components are responsible for the electrical conduction, in which a large number of electrons of moderate mobility coexist with a much smaller number of holes of extremely high mobility. This large electron density well screens the impurity potential and retains the metallic conduction against 7% impurity doping.Peer reviewe

    ゼツアツ コウトウ ウンドウ ケイソク システム ニ ヨル パーキンソンビョウ カンジャ ノ エンゲ ドウタイ ヒョウカ

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    The different forms of flowers in a species have attracted the attention of many evolutionary biologists, including Charles Darwin. In Fagopyrum esculentum (common buckwheat), the occurrence of dimorphic flowers, namely short-styled and long-styled flowers, is associated with a type of self-incompatibility (SI) called heteromorphic SI. The floral morphology and intra-morph incompatibility are both determined by a single genetic locus named the S-locus. Plants with short-styled flowers are heterozygous (S/s) and plants with long-styled flowers are homozygous recessive (s/s) at the S-locus. Despite recent progress in our understanding of the molecular basis of flower development and plant SI systems, the molecular mechanisms underlying heteromorphic SI remain unresolved. By examining differentially expressed genes from the styles of the two floral morphs, we identified a gene that is expressed only in short-styled plants. The novel gene identified was completely linked to the S-locus in a linkage analysis of 1,373 plants and had homology to EARLY FLOWERING 3. We named this gene S-LOCUS EARLY FLOWERING 3 (S-ELF3). In an ion-beam-induced mutant that harbored a deletion in the genomic region spanning S-ELF3, a phenotype shift from short-styled flowers to long-styled flowers was observed. Furthermore, S-ELF3 was present in the genome of short-styled plants and absent from that of long-styled plants both in world-wide landraces of buckwheat and in two distantly related Fagopyrum species that exhibit heteromorphic SI. Moreover, independent disruptions of S-ELF3 were detected in a recently emerged self-compatible Fagopyrum species and a self-compatible line of buckwheat. The nonessential role of S-ELF3 in the survival of individuals and the prolonged evolutionary presence only in the genomes of short-styled plants exhibiting heteromorphic SI suggests that S-ELF3 is a suitable candidate gene for the control of the short-styled phenotype of buckwheat plants

    Histological and Nuclear Medical Comparison of Inflammation After Hemostasis with Non-Thermal Plasma and Thermal Coagulation

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    The objective of this study is to examine the invasiveness of hemostasis by non-thermal plasma (NTP) compared with hemostasis by thermal coagulation (TC). The inflammation recovery process after hemostasis by TC and NTP was compared by using histological methods and nuclear medical molecular imaging. The necrotic areas in the NTP group disappeared after 5 days, whereas they remained 15 days after hemostasis in the TC group. The accumulation of 2-deoxy-2-[F-18] fluoro-D-glucopyranose (F-18-FDG), which reflects the existence of inflammatory cells, was higher in the TC group than in the NTP group on day 15. Thus, this study indicates that hemostasis by NTP is less inflammatory than TC. This report is the first to evaluate inflammation that occurred after hemostasis with medical devices noninvasively

    Vimentin Expression in Tumor Microenvironment Predicts Survival in Pancreatic Ductal Adenocarcinoma: Heterogeneity in Fibroblast Population.

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    BACKGROUND:The tumor microenvironment, including cancer-associated fibroblasts (CAFs), plays various clinical roles in cancer growth. CAFs are a heterogeneous population and express a variety of mesenchymal markers. However, the clinical roles for CAFs expressing different markers in pancreatic ductal adenocarcinoma (PDAC) remain unknown.METHODS:We reviewed 67 resected PDAC patients who had not received preoperative therapy. Each primary tumor was analyzed for vimentin and α-smooth muscle actin (α-SMA) expression by immunohistochemical and dual immunofluorescence staining.RESULTS:There was no correlation between the percentage of cells expressing vimentin and α-SMA in the tumor stroma (Pearson\u27s correlation coefficient: r = 0.171). Higher vimentin expression (p = 0.018) was associated with significantly shorter overall survival in PDAC patients. Using dual immunofluorescence staining, vimentin-positive CAFs were divided into two subpopulations: co-expression of α-SMA, and no co-expression of α-SMA. In PDAC, the level of co-expression had no effect on survival using univariate analysis (median survival time, 33.3 months for low co-expression vs. 18.2 months for high co-expression; log-rank, p = 0.143). However, multivariate analysis clarified that CAFs expressing vimentin alone was an independent predictor of poor survival (p = 0.014; hazard ratio, 2.305; 95% confidence interval, 1.181-4.497).CONCLUSIONS:Vimentin-positive CAFs without co-expression of α-SMA were associated with poor survival in PDAC, and CAFs possessed molecular and functional heterogeneity in this disease
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