2,514 research outputs found

    Coset Character Identities in Superstring Compactifications

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    We apply the coset character identities (generalization of Jacobi's abstruse identity) to compact and noncompact Gepner models. In the both cases, we prove that the partition function actually vanishes due to the spacetime supersymmetry. In the case of the compact models and discrete parts of the noncompact models, the partition function includes the expected vanishing factor. But the character identities used to the continuous part of the noncompact models suggest that these models have twice as many supersymmetry as expected. This fact is an evidence for the conjecture that the holographically dual of the string theory on an actually singular Calabi-Yau manifold is a super CONFORMAL field theory. The extra SUSY charges are interpreted as the superconformal S generators.Comment: 23 pages, LaTeX, no figure. v2:corrected typos, added detailed calculations, added references. v3:corrected typo

    BPS Saturation from Null Reduction

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    We show that any dd-dimensional strictly stationary, asymptotically Minkowskian solution (d≥4)(d\ge 4) of a null reduction of d+1d+1-dimensional pure gravity must saturate the BPS bound provided that the KK vector field can be identified appropriately. We also argue that it is consistent with the field equations.Comment: 10 page

    Appearance of superconductivity in new BiS2 based layered LaO0.5F0.5BiS2

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    We report here synthesis, structural, DC magnetization, and transport studies of new BiS2 based layered LaO0.5F0.5BiS2 superconductor [1]. The sample was synthesized by conventional solid state route via vacuum encapsulation technique at 800oC for 12h. LaO0.5F0.5BiS2 crystallizes in tetragonal P4/nmm space group with lattice parameters a = 4.0703(5){\AA}, c = 13.3902(4){\AA}. Bulk superconductivity is confirmed with superconducting transition temperature (Tc) of 2.7K by DC magnetization measurements. The Isothermal magnetization (MH) measurements showed closed loops with clear signatures of flux pinning and irreversible behavior. The resistivity measurements confirmed an onset Tc of 2.7K. The magneto-transport {\rho}(T,H) measurements showed a resistive broadening and decrease in Tc ({\rho}=0) to lower temperatures with increasing magnetic field. The magnetic phase diagram involving upper critical and irreversibility fields as a function of temperature has been ascertained. Our DC magnetization and electrical transport measurements confirm the appearance of bulk superconductivity in LaO0.5F0.5BiS2 superconductor.Comment: 11 pages figures + Text: First observation/approval of LaO/FBiS2 superconductivity: comments/suggestions: [email protected]

    Chronic Intestinal Inflammatory Condition Generates IL-10-Producing Regulatory B Cell Subset Characterized by CD1d Upregulation

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    AbstractB cells possess a variety of immune functions that are involved in normal and abnormal immune responses, including autoimmune disorders. Through murine models of intestinal inflammation, we here demonstrate a B cell subset that is induced in gut-associated lymphoid tissues and is characterized by CD1d upregulation. This B cell subset appears under a chronic inflammatory environment, produces IL-10, and suppresses progression of intestinal inflammation by downregulating inflammatory cascades associated with IL-1 upregulation and STAT3 activation rather than by altering polarized T helper responses. This study indicates that B cells, by producing cytokines such as IL-10, can act as regulatory cells in immunologically mediated inflammatory reactions

    Free boson formulation of boundary states in W_3 minimal models and the critical Potts model

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    We develop a Coulomb gas formalism for boundary conformal field theory having a WW symmetry and illustrate its operation using the three state Potts model. We find that there are free-field representations for six WW conserving boundary states, which yield the fixed and mixed physical boundary conditions, and two WW violating boundary states which yield the free and new boundary conditions. Other WW violating boundary states can be constructed but they decouple from the rest of the theory. Thus we have a complete free-field realization of the known boundary states of the three state Potts model. We then use the formalism to calculate boundary correlation functions in various cases. We find that the conformal blocks arising when the two point function of Ď•2,3\phi_{2,3} is calculated in the presence of free and new boundary conditions are indeed the last two solutions of the sixth order differential equation generated by the singular vector.Comment: 25 page

    Angle-resolved photoemission spectroscopy of Co-based boride superconductor LaCo1.73Fe0.27B2

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    We have performed angle-resolved photoemission spectroscopy of Co-based boride superconductor LaCo1.73Fe0.27B2 (Tc = 4.1 K), which is isostructural to the 122-type Fe-pnictide superconductor with the pnictogen atom being replaced with boron. We found that the Fermi level is located at a dip in the density of states (DOS) in contrast to Co-pnictide ferromagnets. This reduction in DOS together with the strong Co 3d-B 2p covalent bonding removes the ferromagnetic order and may cause the superconductivity. The energy bands near the Fermi level show higher three dimensionality and a weaker electron-correlation effect than those of Fe pnictides. The Fermi surface topology is considerably different from that of Fe pnictides, suggesting the difference in the superconducting mechanism between boride and pnictide superconductors.Comment: 5 pages, 4 figure

    Characterization of mutations induced by N-methyl-N '-nitro-N-nitrosoguanidine in an industrial Corynebacterium glutamicum strain

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    ArticleMUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS. 649(1-2): 239-244 (2008)journal articl
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