378 research outputs found

    Supersymmetric Extension of GCA in 2d

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    We derive the infinite dimensional Supersymmetric Galilean Conformal Algebra (SGCA) in the case of two spacetime dimensions by performing group contraction on 2d superconformal algebra. We also obtain the representations of the generators in terms of superspace coordinates. Here we find realisations of the SGCA by considering scaling limits of certain 2d SCFTs which are non-unitary and have their left and right central charges become large in magnitude and opposite in sign. We focus on the Neveu-Schwarz sector of the parent SCFTs and develop, in parallel to the GCA studies recently in (arXiv:0912.1090), the representation theory based on SGCA primaries, Ward identities for their correlation functions and their descendants which are null states.Comment: La TeX file, 32 pages; v2: typos corrected, journal versio

    GCA in 2d

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    We make a detailed study of the infinite dimensional Galilean Conformal Algebra (GCA) in the case of two spacetime dimensions. Classically, this algebra is precisely obtained from a contraction of the generators of the relativistic conformal symmetry in 2d. Here we find quantum mechanical realisations of the (centrally extended) GCA by considering scaling limits of certain 2d CFTs. These parent CFTs are non-unitary and have their left and right central charges become large in magnitude and opposite in sign. We therefore develop, in parallel to the usual machinery for 2d CFT, many of the tools for the analysis of the quantum mechanical GCA. These include the representation theory based on GCA primaries, Ward identities for their correlation functions and a nonrelativistic Kac table. In particular, the null vectors of the GCA lead to differential equations for the four point function. The solution to these equations in the simplest case is explicitly obtained and checked to be consistent with various requirements.Comment: 45 pages; v2: 47 pages. Restructured introduction, minor corrections, added references. Journal versio

    Lack of efficacy of Doxil® in TNF-α-based isolated limb perfusion in sarcoma-bearing rats

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    textabstractHere we show that Doxil® has minimal antitumour activity in the isolated limb perfusion (ILP) setting and its activity was not enhanced by the addition of tumour necrosis factor (TNF). Doxil® accumulation in tumour tissue was low and also not augmented by TNF. In contrast, activity of free conventional doxorubicin was enhanced by TNF. We conclude that application of Doxil® in a TNF-based ILP is not a useful alternative to free conventional doxorubicin or melphalan

    Universal time-dependent deformations of Schrodinger geometry

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    We investigate universal time-dependent exact deformations of Schrodinger geometry. We present 1) scale invariant but non-conformal deformation, 2) non-conformal but scale invariant deformation, and 3) both scale and conformal invariant deformation. All these solutions are universal in the sense that we could embed them in any supergravity constructions of the Schrodinger invariant geometry. We give a field theory interpretation of our time-dependent solutions. In particular, we argue that any time-dependent chemical potential can be treated exactly in our gravity dual approach.Comment: 24 pages, v2: references adde

    Enhanced Supersymmetry of Nonrelativistic ABJM Theory

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    We study the supersymmetry enhancement of nonrelativistic limits of the ABJM theory for Chern-Simons level k=1,2k=1,2. The special attention is paid to the nonrelativistic limit (known as `PAAP' case) containing both particles and antiparticles. Using supersymmetry transformations generated by the monopole operators, we find additional 2 kinematical, 2 dynamical, and 2 conformal supercharges for this case. Combining with the original 8 kinematical supercharges, the total number of supercharges becomes maximal: 14 supercharges, like in the well-known PPPP limit. We obtain the corresponding super Schr\"odinger algebra which appears to be isomorphic to the one of the PPPP case. We also discuss the role of monopole operators in supersymmetry enhancement and partial breaking of supersymmetry in nonrelativistic limit of the ABJM theory.Comment: 22 pages, references added, version to appear in JHE

    Charged, conformal non-relativistic hydrodynamics

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    We embed a holographic model of an U(1) charged fluid with Galilean invariance in string theory and calculate its specific heat capacity and Prandtl number. Such theories are generated by a R-symmetry twist along a null direction of a N=1 superconformal theory. We study the hydrodynamic properties of such systems employing ideas from the fluid-gravity correspondence.Comment: 31 pages, 1 figure, JHEP3 style, refs added, typos corrected, missing terms in spatial charge current and field corrections added, to be published in JHE

    Conformal Quivers and Melting Molecules

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    Quiver quantum mechanics describes the low energy dynamics of a system of wrapped D-branes. It captures several aspects of single and multicentered BPS black hole geometries in four-dimensional N=2\mathcal{N} = 2 supergravity such as the presence of bound states and an exponential growth of microstates. The Coulomb branch of an Abelian three node quiver is obtained by integrating out the massive strings connecting the D-particles. It allows for a scaling regime corresponding to a deep AdS2_2 throat on the gravity side. In this scaling regime, the Coulomb branch is shown to be an SL(2,R)SL(2,\mathbb{R}) invariant multi-particle superconformal quantum mechanics. Finally, we integrate out the strings at finite temperature---rather than in their ground state---and show how the Coulomb branch `melts' into the Higgs branch at high enough temperatures. For scaling solutions the melting occurs for arbitrarily small temperatures, whereas bound states can be metastable and thus long lived. Throughout the paper, we discuss how far the analogy between the quiver model and the gravity picture, particularly within the AdS2_2 throat, can be taken.Comment: 49 pages, 16 figure

    Fermions and the Sch/nrCFT Correspondence

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    We consider the problem of Dirac fermions propagating on a spacetime of Schr\"odinger isometry and the associated boundary Euclidean two-point function of fermionic scaling operators of the holographic dual non-relativistic conformal theory. Paying careful attention to the representations of the Schr\"odinger algebra that appear in this problem, we show carefully how the on-shell action is constructed and how the boundary theory may be renormalized consistently by the inclusion of appropriate Galilean invariant boundary counterterms.Comment: 18 page

    Histamine, a vasoactive agent with vascular disrupting potential, improves tumour response by enhancing local drug delivery

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    Tumour necrosis factor (TNF)-based isolated limb perfusion (ILP) is an approved and registered treatment for sarcomas confined to the limbs in Europe since 1998, with limb salvage indexes of 76%. TNF improves drug distribution in solid tumours and secondarily destroys the tumour-associated vasculature (TAV). Here we explore the synergistic antitumour effect of another vasoactive agent, histamine (Hi), in doxorubicin (DXR)-based ILP and evaluate its antivascular effects on TAV. We used our well-established rat ILP model for in vivo studies looking at tumour response, drug distribution and effects on tumour vessels. In vitro studies explored drug interactions at cellular level on tumour cells (BN-175) and Human umbilical vein endothelial cells (HUVEC). There was a 17% partial response and a 50% arrest in tumour growth when Hi was combined to DXR, without important side effects, against 100% progressive disease with DXR alone and 29% arrest in tumour growth for Hi alone. Histology documented an increased DXR leakage in tumour tissue combined to a destruction of the TAV, when Hi was added to the ILP. In vitro no synergy between the drugs was observed. In conclusion, Hi is a vasoactive drug, targeting primarily the TAV and synergises with different chemotherapeutic agents

    Depression and anxiety in relation to catechol-O-methyltransferase Val158Met genotype in the general population: The Nord-Trøndelag Health Study (HUNT)

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    <p>Abstract</p> <p>Background</p> <p>The catechol-O-methyltransferase (COMT) gene contains a functional polymorphism, Val158Met, which has been linked to anxiety and depression, but previous results are not conclusive. The aim of the present study was to examine the relationship between the Val158Met COMT gene polymorphism and anxiety and depression measured by the Hospital Anxiety and Depression Scale (HADS) in the general adult population.</p> <p>Methods</p> <p>In the Nord-Trøndelag Health Study (HUNT) the association between the Val158Met polymorphism and anxiety and depression was evaluated in a random sample of 5531 individuals. Two different cut off scores (≥ 8 and ≥ 11) were used to identify cases with anxiety (HADS-A) and depression (HADS-D), whereas controls had HADS-A <8 and HADS-D <8.</p> <p>Results</p> <p>The COMT genotype distribution was similar between controls and individuals in the groups with anxiety and depression using cut-off scores of ≥ 8. When utilizing the alternative cut-off score HADS-D ≥ 11, Met/Met genotype and Met allele were less common among men with depression compared to the controls (genotype: p = 0.017, allele: p = 0.006). In the multivariate analysis, adjusting for age and heart disease, depression (HADS-D ≥ 11) was less likely among men with the Met/Met genotype than among men with the Val/Val genotype (OR = 0.37, 95% CI = 0.18–0.76).</p> <p>Conclusion</p> <p>In this population-based study, no clear association between the Val158Met polymorphism and depression and anxiety was revealed. The Met/Met genotype was less likely among men with depression defined as HADS-D ≥ 11, but this may be an incidental finding.</p
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