1,989 research outputs found

    Trapping Horizons in the Sultana-Dyer Space-Time

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    The Sultana-Dyer space-time is suggested as a model describing a black hole embedded in an expanding universe. Recently, in \cite{0705.4012}, its global structure is analyzed and the trapping horizons are shown. In the paper, by directly calculating the expansions of the radial null vector fields normal to the space-like two-spheres foliating the trapping horizons, we find that the trapping horizon outside the event horizon in the Sultana-Dyer space-time is a past trapping horizon. Further, we find that the past trapping horizon is an outer, instantaneously degenerate or inner trapping horizon accordingly when the radial coordinate is less than, equal to or greater than some value.Comment: no figures, 5 pages; PCAS and key words are adde

    Birman-Wenzl-Murakami Algebra and the Topological Basis

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    In this paper, we use entangled states to construct 9x9-matrix representations of Temperley-Lieb algebra (TLA), then a family of 9x9-matrix representations of Birman-Wenzl-Murakami algebra (BWMA) have been presented. Based on which, three topological basis states have been found. And we apply topological basis states to recast nine-dimensional BWMA into its three-dimensional counterpart. Finally, we find the topological basis states are spin singlet states in special case.Comment: 11pages, 1 figur

    Gauge Invariant Summation of All QCD Virtual Gluon Exchanges

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    The interpretation of virtual gluons as ghosts in the non-linear gluonic structure of QCD permits the formulation and realization of a manifestly gauge-invariant and Lorentz covariant theory of interacting quarks/anti-quarks, for all values of coupling. The simplest example of quark/anti-quark scattering in a high-energy, quenched, eikonal model at large coupling is shown to be expressible as a set of finite, local integrals which may be evaluated numerically; and before evaluation, it is clear that the result will be dependent only on, and is damped by increasing momentum transfer, while displaying physically-reasonable color dependence in a manner underlying the MIT Bag Model and an effective, asymptotic freedom. A similar but more complicated integral will result from all possible gluonic-radiative corrections to this simplest eikonal model. Our results are compatible with an earlier, field-strength analysis of Reinhardt et al.Comment: 35 pages, no figure

    Lepton flavor violating signals of a little Higgs model at the high energy linear e+ee^{+}e^{-} colliders

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    Littlest Higgs (LH)(LH) model predicts the existence of the doubly charged scalars Φ±±\Phi^{\pm\pm}, which generally have large flavor changing couplings to leptons. We calculate the contributions of Φ±±\Phi^{\pm\pm} to the lepton flavor violating (LFV)(LFV) processes liljγl_{i}\to l_{j}\gamma and liljlklkl_{i}\to l_{j}l_{k}l_{k}, and compare our numerical results with the current experimental upper limits on these processes. We find that some of these processes can give severe constraints on the coupling constant YijY_{ij} and the mass parameter MΦM_{\Phi}. Taking into account the constraints on these free parameters, we further discuss the possible lepton flavor violating signals of Φ±±\Phi^{\pm\pm} at the high energy linear e+ee^{+}e^{-} collider (ILC)(ILC) experiments. Our numerical results show that the possible signals of Φ±±\Phi^{\pm\pm} might be detected via the subprocesses e±e±l±l±e^{\pm}e^{\pm}\to l^{\pm}l^{\pm} in the future ILCILC experiments.Comment: 16 pages, 7 figures. Discussions and references added, typos correcte

    Escalated regeneration in sciatic nerve crush injury by the combined therapy of human amniotic fluid mesenchymal stem cells and fermented soybean extracts, Natto

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    Attenuation of inflammatory cell deposits and associated cytokines prevented the apoptosis of transplanted stem cells in a sciatic nerve crush injury model. Suppression of inflammatory cytokines by fermented soybean extracts (Natto) was also beneficial to nerve regeneration. In this study, the effect of Natto on transplanted human amniotic fluid mesenchymal stem cells (AFS) was evaluated. Peripheral nerve injury was induced in SD rats by crushing a sciatic nerve using a vessel clamp. Animals were categorized into four groups: Group I: no treatment; Group II: fed with Natto (16 mg/day for 7 consecutive days); Group III: AFS embedded in fibrin glue; Group IV: Combination of group II and III therapy. Transplanted AFS and Schwann cell apoptosis, inflammatory cell deposits and associated cytokines, motor function, and nerve regeneration were evaluated 7 or 28 days after injury. The deterioration of neurological function was attenuated by AFS, Natto, or the combined therapy. The combined therapy caused the most significantly beneficial effects. Administration of Natto suppressed the inflammatory responses and correlated with decreased AFS and Schwann cell apoptosis. The decreased AFS apoptosis was in line with neurological improvement such as expression of early regeneration marker of neurofilament and late markers of S-100 and decreased vacuole formation. Administration of either AFS, or Natto, or combined therapy augmented the nerve regeneration. In conclusion, administration of Natto may rescue the AFS and Schwann cells from apoptosis by suppressing the macrophage deposits, associated inflammatory cytokines, and fibrin deposits

    Development and Validation of a 28-gene Hypoxia-related Prognostic Signature for Localized Prostate Cancer.

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    BACKGROUND: Hypoxia is associated with a poor prognosis in prostate cancer. This work aimed to derive and validate a hypoxia-related mRNA signature for localized prostate cancer. METHOD: Hypoxia genes were identified in vitro via RNA-sequencing and combined with in vivo gene co-expression analysis to generate a signature. The signature was independently validated in eleven prostate cancer cohorts and a bladder cancer phase III randomized trial of radiotherapy alone or with carbogen and nicotinamide (CON). RESULTS: A 28-gene signature was derived. Patients with high signature scores had poorer biochemical recurrence free survivals in six of eight independent cohorts of prostatectomy-treated patients (Log rank test P \u3c .05), with borderline significances achieved in the other two (P \u3c .1). The signature also predicted biochemical recurrence in patients receiving post-prostatectomy radiotherapy (n = 130, P = .007) or definitive radiotherapy alone (n = 248, P = .035). Lastly, the signature predicted metastasis events in a pooled cohort (n = 631, P = .002). Prognostic significance remained after adjusting for clinic-pathological factors and commercially available prognostic signatures. The signature predicted benefit from hypoxia-modifying therapy in bladder cancer patients (intervention-by-signature interaction test P = .0026), where carbogen and nicotinamide was associated with improved survival only in hypoxic tumours. CONCLUSION: A 28-gene hypoxia signature has strong and independent prognostic value for prostate cancer patients

    Flavon exchange effects in models with abelian flavor symmetry

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    In models with abelian flavor symmetry the small mixing angles and mass ratios of quarks and leptons are typically given by powers of small parameters characterizing the spontaneous breaking of flavor symmetry by "flavon" fields. If the scale of the breaking of flavor symmetry is near the weak scale, flavon exchange can lead to interesting flavor-violating and CP violating effects. These are studied. It is found that d_e, mu -> e + gamma, and mu-e conversion on nuclei can be near present limits. For significant range of parameters mu-e conversion can be the most sensitive way to look for such effects.Comment: 19 pages, 5 Postscript figures, LATE

    Cascade-based attacks on complex networks

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    We live in a modern world supported by large, complex networks. Examples range from financial markets to communication and transportation systems. In many realistic situations the flow of physical quantities in the network, as characterized by the loads on nodes, is important. We show that for such networks where loads can redistribute among the nodes, intentional attacks can lead to a cascade of overload failures, which can in turn cause the entire or a substantial part of the network to collapse. This is relevant for real-world networks that possess a highly heterogeneous distribution of loads, such as the Internet and power grids. We demonstrate that the heterogeneity of these networks makes them particularly vulnerable to attacks in that a large-scale cascade may be triggered by disabling a single key node. This brings obvious concerns on the security of such systems.Comment: 4 pages, 4 figures, Revte

    Charged Higgs boson contribution to νˉee\bar{\nu}_e-e scattering from low to ultrahigh energy in Higgs triplet model

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    We study the νˉee\bar{\nu}_e-e scattering from low to ultrahigh energy in the framework of Higgs Triplet Model (HTM). We add the contribution of charged Higgs boson exchange to the total cross section of the scattering. We obtain the upper bound hee/MH±2.8×103GeV1h_{ee}/M_{H^\pm}\lesssim2.8\times10^{-3}GeV^{-1} in this process from low energy experiment. We show that by using the upper bound obtained, the charged Higgs contribution can give enhancements to the total cross section with respect to the SM prediction up to 5.16% at E1014E\leq10^{14} eV and maximum at sMH±2s\approx M_{H^\pm}^2 and would help to determine the feasibility experiments to discriminate between SM and HTM at current available facilities.Comment: 6 pages, 6 figure

    Lepton flavor violation decays τμP1P2\tau^-\to \mu^- P_1 P_2 in the topcolor-assisted technicolor model and the littlest Higgs model with TT parity

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    The new particles predicted by the topcolor-assisted technicolor (TC2TC2) model and the littlest Higgs model with T-parity (called LHTLHT model) can induce the lepton flavor violation (LFVLFV) couplings at tree level or one loop level, which might generate large contributions to some LFVLFV processes. Taking into account the constraints of the experimental data on the relevant free parameters, we calculate the branching ratios of the LFVLFV decay processes τμP1P2\tau^-\to\mu^- P_1 P_2 with P1P2P_1 P_2 = π+π\pi^+\pi^-, K+KK^+K^- and K0K0ˉK^0\bar{K^0} in the context of these two kinds of new physics models. We find that the TC2TC2 model and the LHTLHT model can indeed produce significant contributions to some of these LFVLFV decay processes.Comment: 24 pages, 7 figure
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