1,774 research outputs found

    Painlev\'e property, local and nonlocal symmetries and symmetry reductions for a (2+1)-dimensional integrable KdV equation

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    The Painlev\'e property for a (2+1)-dimensional Korteweg-de Vries (KdV) extension, the combined KP3 (Kadomtsev- Petviashvili) and KP4 (cKP3-4) is proved by using Kruskal's simplification. The truncated Painlev\'e expansion is used to find the Schwartz form, the B\"acklund/Levi transformations and the residual nonlocal symmetry. The residual symmetry is localized to find its finite B\"acklund transformation. The local point symmetries of the model constitute a centerless Kac-Moody-Virasoro algebra. The local point symmetries are used to find the related group invariant reductions including a new Lax integrable model with a fourth order spectral problem. The finite transformation theorem or the Lie point symmetry group is obtained by using a direct method.Comment: 9 page

    UNDERSTANDING USERS’ WILLINGNESS TO REPORT ONLINE HARASSMENT ON SOCIAL NETWORKING SITES: THE ROLE OF EFFICACY

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    Online harassment is an emerging global societal problem, with its pervasiveness and persistence creating long-lasting adverse psychological consequences to victims. While many social networking sites (SNSs) have started launching online reporting systems to combat online harassment, surprisingly, little empirical research has examined users’ willingness to use the system for reporting online harassment. In this study, we propose a research model explaining the role of efficacy in using the online reporting system of SNSs to report online harassment. We expect that the results of this study make significant contributions to research and practice

    Hybrid quantum device based on NV centers in diamond nanomechanical resonators plus superconducting waveguide cavities

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    We propose and analyze a hybrid device by integrating a microscale diamond beam with a single built-in nitrogen-vacancy (NV) center spin to a superconducting coplanar waveguide (CPW) cavity. We find that under an ac electric field the quantized motion of the diamond beam can strongly couple to the single cavity photons via dielectric interaction. Together with the strong spin-motion interaction via a large magnetic field gradient, it provides a hybrid quantum device where the dia- mond resonator can strongly couple both to the single microwave cavity photons and to the single NV center spin. This enables coherent information transfer and effective coupling between the NV spin and the CPW cavity via mechanically dark polaritons. This hybrid spin-electromechanical de- vice, with tunable couplings by external fields, offers a realistic platform for implementing quantum information with single NV spins, diamond mechanical resonators, and single microwave photons.Comment: Accepted by Phys. Rev. Applie

    Black Holes and Photons with Entropic Force

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    We study entropic force effects on black holes and photons. We find that application of an entropic analysis restricts the radial change ΔR\Delta R of a black hole of radius RHR_{\mathrm{H}}, due to a test particle of a Schwartzchild radius RhR_{h} moving towards the black hole by Δx\Delta x near black body surface, to be given by a relation RHΔR=RhΔx/2R_{\mathrm{H}} \Delta R= R_h \Delta x/2, or {\Delta R}/{\lambdabar_M} = {\Delta x}/{2 \lambdabar_m}. We suggest a new rule regarding entropy changes in different dimensions, \Delta S= 2\pi k D \Delta l /\lambdabar, which unifies Verlinde's conjecture and the black hole entropy formula. We also propose to extend the entropic force idea to massless particles such as a photon. We find that there is an entropic force on a photon of energy EγE_\gamma, with F=GMmγ/R2F=G M m_{\gamma}/R^2, and therefore the photon has an effective gravitational mass mγ=Eγ/c2m_\gamma = E_\gamma/c^2.Comment: 4 Latex pages, no figure

    Simple scheme for expanding a polarization-entangled W state by adding one photon

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    We propose a simple scheme for expanding a polarization-entangled W state. By mixing a single photon and one of the photons in an n-photon W state at a polarization-dependent beam splitter (PDBS), we can obtain an (n+1)-photon W state after post-selection. Our scheme also opens the door for generating n-photon W states using single photons and linear optics.Comment: 3 pages, 2 figure

    Quantum theory of electronic double-slit diffraction

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    The phenomena of electron, neutron, atomic and molecular diffraction have been studied by many experiments, and these experiments are explained by some theoretical works. In this paper, we study electronic double-slit diffraction with quantum mechanical approach. We can obtain the results: (1) When the slit width aa is in the range of 3λ50λ3\lambda\sim 50\lambda we can obtain the obvious diffraction patterns. (2) when the ratio of d+aa=n(n=1,2,3,)\frac{d+a}{a}=n (n=1, 2, 3,\cdot\cdot\cdot), order 2n,3n,4n,2n, 3n, 4n,\cdot\cdot\cdot are missing in diffraction pattern. (3)When the ratio of d+aan(n=1,2,3,)\frac{d+a}{a}\neq n (n=1, 2, 3,\cdot\cdot\cdot), there isn't missing order in diffraction pattern. (4) We also find a new quantum mechanics effect that the slit thickness cc has a large affect to the electronic diffraction patterns. We think all the predictions in our work can be tested by the electronic double-slit diffraction experiment.Comment: 9pages, 14figure

    Control of Intestinal Inflammation, Colitis-Associated Tumorigenesis, and Macrophage Polarization by Fibrinogen-Like Protein 2

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    Fibrinogen-like protein 2 (Fgl2) is critical for immune regulation in the inflammatory state. Elevated Fgl2 levels are observed in patients with inflammatory bowel disease (IBD), but little is known about its functional significance. In this study, we sought to investigate the role of Fgl2 in the development of intestinal inflammation and colitis-associated colorectal cancer (CAC). Here, we report that Fgl2 deficiency increased susceptibility to dextran sodium sulfate-induced colitis and CAC in a mouse model. During colitis development, the expression of the membrane-bound and secreted forms of Fgl2 (mFgl2 and sFgl2, respectively) in the colon were increased and predominantly expressed by colonic macrophages. In addition, using bone marrow chimeric mice, we determined that Fgl2 function in colitis is strictly related to its expression in the hematopoietic cells. Loss of Fgl2 induced the polarization of M1, but suppressed that of M2 both in vivo and in vitro, independent of intestinal inflammation. Thus, Fgl2 suppresses intestinal inflammation and CAC development through its role in macrophage polarization and may serve as a therapeutic target in inflammatory diseases, including IBD

    Protein Kinase B (Akt) Promotes Pathological Angiogenesis in Murine Model of Oxygen-Induced Retinopathy

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    Akt, or protein kinase B, is an important signaling molecule that modulates many cellular processes such as cell growth, survival, and metabolism. However, the vivo roles and effectors of Akt in retinal angiogenesis are not explicitly clear. We therefore detected the expression of Akt using Western blotting or RT-PCR technologies in an animal model of oxygen-induced retinopathy, and investigated the effects of recombinant Akt on inhibiting vessels loss and Akt inhibitor on suppressing experimental retinal neovascularization in this model. We showed that in the hyperoxic phase of oxygen-induced retinopathy, the expression of Akt was greatly suppressed. In the hypoxic phase, the expression of Akt was increased dramatically. No significant differences were found in normoxic groups. Compared with control groups, administration of the recombinant Akt in the first phase of retinopathy markedly reduced capillary-free areas, while the administration of the Akt inhibitor in the second phase of retinopathy significantly decreased retinal neovascularization but capillary-free areas. These results indicate that Akt play a critical role in the pathological process (vessels loss and neovascularization) of mouse model of oxygen-induced retinopathy, which may provide a valubale therapeutic tool for ischemic-induced retinal diseases

    Rheb1 mediates DISC1-dependent regulation of new neuron development in the adult hippocampus

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    Acknowledgments: We thank D. Weinberger, D. St. Clair and D. Valle for discussion, Jaden Shin for gene expression analyses, members of Ming and Song Laboratories for help and critical comments, L. Liu, Y. Cai, Q. Hussaini, and M. Jardine-Alborz for technical support. Funding: This work was supported by NIH (NS048271, MH105128), NARSAD, and MSCRF to G-l.M., by NIH (NS047344 and NS093772) and MSCRF to H.S., by NARSAD and NIH (NS093772) to K.C., and by NARSAD to E.K.Peer reviewedPublisher PD
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