234 research outputs found

    D-branes and Closed String Field Theory

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    We construct solitonic states in the OSp invariant string field theory, which are BRST invariant in the leading order of regularization parameter. One can show that these solitonic states describe D-branes and ghost D-branes, by calculating the scattering amplitudes.Comment: 8 pages, 2 figures, based on an invited talk presented at the international workshop "Progress of String Theory and Quantum Field Theory" (Osaka City University, December 7-10, 2007), to be published in the proceeding

    Observables and Correlation Functions in OSp Invariant String Field Theory

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    We define BRST invariant observables in the OSp invariant closed string field theory for bosonic strings. We evaluate correlation functions of these observables and show that the S-matrix elements derived from them coincide with those of the light-cone gauge string field theory.Comment: 23 page

    Light-Cone Gauge String Field Theory in Noncritical Dimensions

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    We study light-cone gauge string field theory in noncritical space-time dimensions. Such a theory corresponds to a string theory in a Lorentz noninvariant background. We identify the worldsheet theory for the longitudinal coordinate variables X±X^\pm and study its properties. It is a CFT with the right value of Virasoro central charge, using which we propose a BRST invariant formulation of the worldsheet theory.Comment: 27 pages, 2 figure

    Light-cone Gauge NSR Strings in Noncritical Dimensions

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    Light-cone gauge NSR string theory in noncritical dimensions should correspond to a string theory with a nonstandard longitudinal part. Supersymmetrizing the bosonic case [arXiv:0909.4675], we formulate a superconformal worldsheet theory for the longitudinal variables X^{\pm}, \psi^{\pm}. We show that with the transverse variables and the ghosts combined, it is possible to construct a nilpotent BRST charge.Comment: 22 pages, 1 figur

    D-brane States and Annulus Amplitudes in OSp Invariant Closed String Field Theory

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    In the OSp invariant closed string field theory, we construct the states corresponding to parallel D-branes that are located at different points in the space-time. Using these states, we evaluate annulus amplitudes. We show that the results coincide with those of first quantized string theory.Comment: 14 pages, 3 figure

    On the Site Amplification Characteristics in San Francisco Bay Region Due to the 1989 Loma Prieta Earthquake Type Loadings

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    A large earthquake occurred in the Santa Cruz mountains, California, on 17 October 1989, and many structures and facilities in the San Francisco Bay region suffered fatal damage from the seismic motion. In order to evaluate the ground amplification characteristics in the region, the practical method of representing the seismic wave field may be necessary. This paper is concerned with a theoretical analysis and numerical evaluation based on the wave propagation theory to find the dynamic characteristics of the slightly sedimental basin around the San Francisco Bay due to the Loma Prieta earthquake type excitations. Numerical examples of this system are shown in the domain of frequency and time

    D-brane States and Disk Amplitudes in OSp Invariant Closed String Field Theory

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    We construct solitonic states in the OSp invariant string field theory, which are BRST invariant in the leading order of regularization parameter ϵ\epsilon. We calculate the disk amplitudes using these solitonic states and show that they describe D-branes and ghost D-branes.Comment: 37 pages, 8 figure

    Light-cone Gauge Superstring Field Theory and Dimensional Regularization II

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    We propose a dimensional regularization scheme to deal with the divergences caused by colliding supercurrents inserted at the interaction points, in the light-cone gauge NSR superstring field theory. We formulate the theory in dd dimensions and define the amplitudes as analytic functions of dd. With an appropriately chosen three-string interaction term and large negative dd, the tree level amplitudes for the (NS,NS) closed strings can be recast into a BRST invariant form, using the superconformal field theory proposed in Ref.[arXiv:0911.3704]. We show that in the limit d10d \to 10 they coincide with the results of the first quantized theory. Therefore we obtain the desired results without adding any contact interaction terms to the action.Comment: 23 pages; v2: minor modifications; v3: revised argument in section 3, added appendix C, results unchanged; v4: added clarifications, two figures and a footnote; v5: minor modification

    Present and Future of EGFR Inhibitors for Head and Neck Squamous Cell Cancer

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    Although EGFR is expressed at high levels in head and neck squamous cell carcinomas (HNSCCs) and mutations are extremely rare, monotherapy with EGFR inhibitors has shown limited success. The PI3kinase/Akt pathway is responsible for cellular survival, and inhibition of phosphatidylinositol (PI) synthesis has antiproliferative, anti-invasive, and antiangiogenesis effects on HNSCC. Molecular crosstalk has been observed between EGFR and IGF1R signaling through the PI3kinase/Akt pathway in HNSCC, as has molecular crosstalk between the NFκB and STAT3 signaling pathways. Therefore, the combination of an EGFR antagonist with an agent that inhibits the activation of both Akt and NFκB may overcome resistance to EGFR antagonists in HNSCC
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