127 research outputs found

    Wall Solution with Weak Gravity Limit in Five Dimensional Supergravity

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    In five-dimensional supergravity, an exact solution of BPS wall is found for a gravitational deformation of the massive Eguchi-Hanson nonlinear sigma model. The warp factor decreases for both infinities of the extra dimension. Thin wall limit gives the Randall-Sundrum model without fine-tuning of input parameters. We also obtain wall solutions with warp factors which are flat or increasing in one side, by varying a deformation parameter of the potential.Comment: Typo corrected, reference added, 13pages, 5 figure

    Deformed Prepotential, Quantum Integrable System and Liouville Field Theory

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    We study the dual descriptions recently discovered for the Seiberg-Witten theory in the presence of surface operators. The Nekrasov partition function for a four-dimensional N=2 gauge theory with a surface operator is believed equal to the wave-function of the corresponding integrable system, or the Hitchin system, and is identified with the conformal block with a degenerate field via the AGT relation. We verify the conjecture by showing that the null state condition leads to the Schrodinger equations of the integrable systems. Furthermore, we show that the deformed prepotential emerging from the period integrals of the principal function corresponds to monodromy operation of the conformal block. We also give the instanton partition functions for the asymptotically free SU(2) gauge theories in the presence of the surface operator via the AGT relation. We find that these partition functions involve the counting of two- and four-dimensional instantons.Comment: 47 pages; v2: references added, typos corrected; v3: a version to appear in Nuclear Physics

    Wild-Type Monomeric α-Synuclein Can Impair Vesicle Endocytosis and Synaptic Fidelity via Tubulin Polymerization at the Calyx of Held

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    α-Synuclein is a presynaptic protein the function of which has yet to be identified, but its neuronal content increases in patients of synucleinopathies including Parkinson\u27s disease. Chronic overexpression of α-synuclein reportedly expresses various phenotypes of synaptic dysfunction, but the primary target of its toxicity has not been determined. To investigate this, we acutely loaded human recombinant α-synuclein or its pathological mutants in their monomeric forms into the calyces of Held presynaptic terminals in slices from auditorily mature and immature rats of either sex. Membrane capacitance measurements revealed significant and specific inhibitory effects of WT monomeric α-synuclein on vesicle endocytosis throughout development. However, the α-synuclein A53T mutant affected vesicle endocytosis only at immature calyces, whereas the A30P mutant had no effect throughout. The endocytic impairment by WT α-synuclein was rescued by intraterminal coloading of the microtubule (MT) polymerization blocker nocodazole. Furthermore, it was reversibly rescued by presynaptically loaded photostatin-1, a photoswitcheable inhibitor of MT polymerization, in a light-wavelength-dependent manner. In contrast, endocytic inhibition by the A53T mutant at immature calyces was not rescued by nocodazole. Functionally, presynaptically loaded WT α-synuclein had no effect on basal synaptic transmission evoked at a low frequency, but significantly attenuated exocytosis and impaired the fidelity of neurotransmission during prolonged high-frequency stimulation. We conclude that monomeric WT α-synuclein primarily inhibits vesicle endocytosis via MT overassembly, thereby impairing high-frequency neurotransmission.SIGNIFICANCE STATEMENT Abnormal α-synuclein abundance is associated with synucleinopathies including Parkinson\u27s disease, but neither the primary target of α-synuclein toxicity nor its mechanism is identified. Here, we loaded monomeric α-synuclein directly into mammalian glutamatergic nerve terminals and found that it primarily inhibits vesicle endocytosis and subsequently impairs exocytosis and neurotransmission fidelity during prolonged high-frequency stimulation. Such α-synuclein toxicity could be rescued by blocking microtubule polymerization, suggesting that microtubule overassembly underlies the toxicity of acutely elevated α-synuclein in the nerve terminal

    Refined Topological Vertex and Instanton Counting

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    It has been proposed recently that topological A-model string amplitudes for toric Calabi-Yau 3-folds in non self-dual graviphoton background can be caluculated by a diagrammatic method that is called the ``refined topological vertex''. We compute the extended A-model amplitudes for SU(N)-geometries using the proposed vertex. If the refined topological vertex is valid, these computations should give rise to the Nekrasov's partition functions of N=2 SU(N) gauge theories via the geometric engineering. In this article, we verify the proposal by confirming the equivalence between the refined A-model amplitude and the K-theoretic version of the Nekrasov's partition function by explicit computation.Comment: 22 pages, 6 figures, minor correction

    Difference between carbohydrate antigen 19-9 and fluorine-18 fluorodeoxyglucose positron emission tomography in evaluating the treatment efficacy of neoadjuvant treatment in patients with resectable and borderline resectable pancreatic ductal adenocarcinoma: Results of a dual-center study

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    kita, H, Takahashi, H, Eguchi, H, et al. Difference between carbohydrate antigen 19‐9 and fluorine‐18 fluorodeoxyglucose positron emission tomography in evaluating the treatment efficacy of neoadjuvant treatment in patients with resectable and borderline resectable pancreatic ductal adenocarcinoma: Results of a dual‐center study. Ann Gastroenterol Surg. 2020; 00: 1– 9. https://doi.org/10.1002/ags3.12418

    Massive Nonlinear Sigma Models and BPS Domain Walls in Harmonic Superspace

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    Four-dimensional massive N=2 nonlinear sigma models and BPS wall solutions are studied in the off-shell harmonic superspace approach in which N=2 supersymmetry is manifest. The general nonlinear sigma model can be described by an analytic harmonic potential which is the hyper-Kahler analog of the Kahler potential in N=1 theory. We examine the massive nonlinear sigma model with multi-center four-dimensional target hyper-Kahler metrics and derive the corresponding BPS equation. We study in some detail two particular cases with the Taub-NUT and double Taub-NUT metrics. The latter embodies, as its two separate limits, both Taub-NUT and Eguchi-Hanson metrics. We find that domain wall solutions exist only in the double Taub-NUT case including its Eguchi-Hanson limit.Comment: 35 pages, 4 figures, minor corrections and references added, to appear in NP

    Surface Operator, Bubbling Calabi-Yau and AGT Relation

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    Surface operators in N=2 four-dimensional gauge theories are interesting half-BPS objects. These operators inherit the connection of gauge theory with the Liouville conformal field theory, which was discovered by Alday, Gaiotto and Tachikawa. Moreover it has been proposed that toric branes in the A-model topological strings lead to surface operators via the geometric engineering. We analyze the surface operators by making good use of topological string theory. Starting from this point of view, we propose that the wave-function behavior of the topological open string amplitudes geometrically engineers the surface operator partition functions and the Gaiotto curves of corresponding gauge theories. We then study a peculiar feature that the surface operator corresponds to the insertion of the degenerate fields in the conformal field theory side. We show that this aspect can be realized as the geometric transition in topological string theory, and the insertion of a surface operator leads to the bubbling of the toric Calabi-Yau geometry.Comment: 36 pages, 14 figures. v2: minor changes and typos correcte
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