828 research outputs found

    Instanton Calculus in R-R 3-form Background and Deformed N=2 Super Yang-Mills Theory

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    We study the ADHM construction of instantons in N=2 supersymmetric Yang-Mills theory deformed in constant Ramond-Ramond (R-R) 3-form field strength background in type IIB superstrings. We compare the deformed instanton effective action with the effective action of fractional D3/D(-1) branes at the orbifold singularity of C^2/Z_2 in the same R-R background. We find discrepancy between them at the second order in deformation parameters, which comes from the coupling of the translational zero modes of the D(-1)-branes to the R-R background. We improve the deformed action by adding a term with space-time dependent gauge coupling. Although the space-time action differs from the action in the omega-background, both actions lead to the same instanton equations of motion at the lowest order in gauge coupling.Comment: 27 pages, version to appear in JHE

    Deformation of Super Yang-Mills Theories in R-R 3-form Background

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    We study deformation of N=2 and N=4 super Yang-Mills theories, which are obtained as the low-energy effective theories on the (fractional) D3-branes in the presence of constant Ramond-Ramond 3-form background. We calculate the Lagrangian at the second order in the deformation parameter from open string disk amplitudes. In N=4 case we find that all supersymmetries are broken for generic deformation parameter but part of supersymmetries are unbroken for special case. We also find that classical vacua admit fuzzy sphere configuration. In N=2 case we determine the deformed supersymmetries. We rewrite the deformed Lagrangians in terms of N=1 superspace, where the deformation is interpreted as that of coupling constants.Comment: v2: reference added, v3: published version in JHE

    Structure and evolution of the human IKBA gene

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    IκBα belongs to a gene family whose members are characterized by their 6-7 Ankyrin repeats, which allow them to interact with members of the Rel family of transcription factors. We have sequenced a human IκBα genomic clone to determine its gene structure. The human IκBα gene (IKBA) has six exons and five introns that span approximately 3.5 kb. This genomic organization is similar to that of other members of the Ankyrin gene family. The humanIKBAgene shares similar intron/exon boundaries with the humanBCL3andNFKB2genes, which is consistent with their conserved Ankyrin repeats. To examine further the evolutionary relationship between human IκBα and other members of its gene family, we performed a phylogenetic analysis. Although the resulting phylogenetic tree does not identify a common ancestor of the IκBα gene family, it indicates that this family diverges into two groups based on structure and function

    Spin-orbit final state interaction in the framework of Glauber theory for (e,e'p) reactions

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    We investigate the reactions D(e,e'p)n and D(\vec e,e'p)n at GeV energies and discuss the opportunities to distinguish between different models for the nuclear ground state by measuring the response functions. In calculating the final-state interaction (FSI) we employ Glauber theory, and we also include relativistic effects in the electromagnetic current. We include not only the central FSI, but also the spin-orbit FSI which is usually neglected in (e,e'p) calculations within the Glauber framework and we show that this contribution plays a crucial role for the fifth response function. All of the methods developed here can be applied to any target nucleus.Comment: 20 pages, 12 figures, minor change in figures 3 and 4 (changed beam energy), correction of error in figure 4 in the previous replacemen

    Path integrals approach to resisitivity anomalies in anharmonic systems

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    Different classes of physical systems with sizeable electron-phonon coupling and lattice distortions present anomalous resistivity behaviors versus temperature. We study a molecular lattice Hamiltonian in which polaronic charge carriers interact with non linear potentials provided by local atomic fluctuations between two equilibrium sites. We study a molecular lattice Hamiltonian in which polaronic charge carriers interact with non linear potentials provided by local atomic fluctuations between two equilibrium sites. A path integral model is developed to select the class of atomic oscillations which mainly contributes to the partition function and the electrical resistivity is computed in a number of representative cases. We argue that the common origin of the observed resistivity anomalies lies in the time retarded nature of the polaronic interactions in the local structural instabilities.Comment: 4 figures, to appear in Phys.Rev.B, May 1st (2001

    Non-perturbative effects and the resummed Higgs transverse momentum distribution at the LHC

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    We investigate the form of the non-perturbative parameterization in both the impact parameter (b) space and transverse momentum (p_T) space resummation formalisms for the transverse momentum distribution of single massive bosons produced at hadron colliders. We propose to analyse data on Upsilon hadroproduction as a means of studying the non-perturbative contribution in processes with two gluons in the initial state. We also discuss the theoretical errors on the resummed Higgs transverse momentum distribution at the LHC arising from the non-perturbative contribution.Comment: 22 pages, 10 figure

    Non-Arrhenius Behavior of Secondary Relaxation in Supercooled Liquids

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    Dielectric relaxation spectroscopy (1 Hz - 20 GHz) has been performed on supercooled glass-formers from the temperature of glass transition (T_g) up to that of melting. Precise measurements particularly in the frequencies of MHz-order have revealed that the temperature dependences of secondary beta-relaxation times deviate from the Arrhenius relation in well above T_g. Consequently, our results indicate that the beta-process merges into the primary alpha-mode around the melting temperature, and not at the dynamical transition point T which is approximately equal to 1.2 T_g.Comment: 4 pages, 4 figures, revtex

    Chromosomal localization of the genes encoding the p50/p105 subunits of NF-κB (NFKB2) and the IκB/MAD-3 (NFKBI) inhibitor of NF-κB to 4q24 and 14q13, respectively

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    The regulation of expression of a variety of genes involved in immune function, inflammation, and cellular growth control, as well as control of expression of certain viruses such as the human immunodeficiency virus (HIV), is dependent on the transcription factor NF-κB. In many cells, NF-κB is found in the cytoplasm where it is associated with an inhibitor protein known as IκB. Recently the genes encoding the p50 and p65 subunits of NF-κB, as well as one form of IκB/MAD-3 (NFKBI), have been cloned. As part of our goal to determine the chromosomal organization of members of the REL/NFKB family, as well as their inhibitors, we localized the NFKBp50/p105 (NFKB2) and IκB/MAD-3 (NFKBI) genes to human chromosome bands 4q24 and 14q13, respectively

    Weak antiferromagnetism due to Dzyaloshinskii-Moriya interaction in Ba3_3Cu2_2O4_4Cl2_2

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    The antiferromagnetic insulating cuprate Ba3_3Cu2_2O4_4Cl2_2 contains folded CuO2_2 chains with four magnetic copper ions (S=1/2S=1/2) per unit cell. An underlying multiorbital Hubbard model is formulated and the superexchange theory is developed to derive an effective spin Hamiltonian for this cuprate. The resulting spin Hamiltonian involves a Dzyaloshinskii-Moriya term and a more weak symmetric anisotropic exchange term besides the isotropic exchange interaction. The corresponding Dzyaloshinskii-Moriya vectors of each magnetic Cu-Cu bond in the chain reveal a well defined spatial order. Both, the superexchange theory and the complementary group theoretical consideration, lead to the same conclusion on the character of this order. The analysis of the ground-state magnetic properties of the derived model leads to the prediction of an additional noncollinear modulation of the antiferromagnetic structure. This weak antiferromagnetism is restricted to one of the Cu sublattices.Comment: 13 pages, 1 table, 4 figure

    A PROPOSAL OF MUDA INDICATOR AGENT TO ESTIMATE LEAN MANUFACTURING VERIFICATION

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    Lean Manufacturing (LM) is the philosophy to improve productivity of manufacturing system by eliminating wastes. LM tools have been implemented as software tools in order to implement this philosophy. However, implementing LM in factories does not always succeed because of several reasons; insufficient expertise and knowledge on LM practitioners, dynamic feature of complicated manufacturing processes, difficulty in quantifying the benefits of LM implementation, and etc. Simulation-based approaches have been proposed to support LM implementation, and their effectiveness has been reported in several papers. However, they are not suitable for LM practitioners who are not familiar with simulation software. Therefore, some appropriate niche techniques to bridge the gap between LM practitioners and simulation-based approaches are expected to achieve successful LM implementation. This research proposes an agent-based approach to LM implementation using Muda Indicator (MI) agent to narrow the gap. This paper presents the overview of MI agent, defines quartile calculation to determine Muda level, explains MI indication by MI agent, and shows the feasibility of MI agent using a manufacturing process model. The feasibility study showed how MI agent presents transition of quantifying wastes during simulation in a dynamic manner
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