652 research outputs found

    Multiloop Amplitudes of Light-cone Gauge Superstring Field Theory: Odd Spin Structure Contributions

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    We study the odd spin structure contributions to the multiloop amplitudes of light-cone gauge superstring field theory. We show that they coincide with the amplitudes in the conformal gauge with two of the vertex operators chosen to be in the pictures different from the standard choice, namely (-1,-1) picture in the type II case and -1 picture in the heterotic case. We also show that the contact term divergences can be regularized in the same way as in the amplitudes for the even structures and we get the amplitudes which coincide with those obtained from the first-quantized approach.Comment: 32 pages, 2 figure

    Light-cone Gauge String Field Theory and Dimensional Regularization

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    We review our recent proposals to dimensionally regularize the light-cone gauge string field theory.Comment: 10 pages, 5 figures, A contribution to the proceedings of "SFT2010", held at YITP, Kyoto, Japan, October 18-22, 201

    Matrix Model for Dirichlet Open String

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    We discuss the open string ending on D pp-branes in IKKT framework. First we determine the boundary conditions of Green-Schwarz superstring which are consistent with supersymmetry and κ\kappa-symmetry. We point out some subtleties arising from taking the Schild gauge and show that in this gauge the system incorporates the limited dimensional D pp-branes (p=3,7p=3,7). The matrix regularization for the Dirichlet open string is given by gauge group SO(N). When p=3p=3, the matrix model becomes the dimensional reduction of a 6 dimensional N=1{\cal N}=1 super Yang-Mills theory.Comment: 9 pages, LaTe

    Extending Geant4 Parallelism with External Libraries (MPI, TBB) and Its Use on HPC Resources

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    With Geant4 Version 10.0, released in December 2013, one of the most widely used Monte-Carlo codes has been ported to take full advantage of multi- and many-core CPUs thanks to the introduction of event-level parallelism via multithreading. In this paper we review recent developments to allow for a better integration of parallel Geant4 jobs with external libraries. We have chosen to develop examples using the popular Intel Threading Building Block (for short TBB) as an alternative parallelization approach to the native Geant4 POSIX. To simplify the scaling of a Geant4 application across nodes on a cluster we are improving the support of MPI in Geant4. In particular it is now possible to run an hybrid MPI/MT application that uses MPI to scale across nodes and MT to scale across cores. %The recent developments allow users to easily implement parallel application resources that scale on a very large number of nodes and cores typical of HPC resources.Comment: conferenc

    Amplitudes in Noncritical Dimensions and Dimensional Regularization

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    We study how the dimensional regularization works in the light-cone gauge string field theory. We show that it is not necessary to add a contact term to the string field theory action as a counter term in this regularization at least at the tree level. We also investigate the one-loop amplitudes of the bosonic theory in noncritical dimensions and show that they are modular invariant.Comment: 10 pages, 1 figure, A contribution to the proceedings of "SFT2010", held at YITP, Kyoto, Japan, October 18-22, 201

    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

    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

    Suppressive Effects of Selected Food Phytochemicals on CD74 Expression in NCI-N87 Gastric Carcinoma Cells

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    Helicobacter pylori (H. pylori) is one of the most widespread human pathogens, and plays major roles in chronic gastritis and gastric cancer. CD74 of gastric epithelial cells has recently been identified as an adhesion molecule to urease in H. pylori. In this study, we found that CD74 is highly expressed in a constitutive manner in NCI-N87 human gastric carcinoma cells at both the protein and mRNA levels as compared with Hs738St./Int fetal gastric cells. Subsequently, a novel cell-based ELISA able to rapidly screen the suppressive agents of CD74 expression was established. NCI-N87 cells were treated separately with 25 different food phytochemicals (4–100 µM) for 48 h and subjected to our novel assay. From those results, a citrus coumarin, bergamottin, was indicated to be the most promising compound with an LC50/IC50 value greater than 7.1, followed by luteolin (>5.4), nobiletin (>5.3), and quercetin (>5.1). Our findings suggest that these CD74 suppressants are unique candidates for preventing H. pylori adhesion and subsequent infection with reasonable action mechanisms
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