128 research outputs found

    From Correlators to Wilson Loops in Chern-Simons Matter Theories

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    We study n-point correlation functions for chiral primary operators in three dimensional supersymmetric Chern-Simons matter theories. Our analysis is carried on in N=2 superspace and covers N=2,3 supersymmetric CFT's, the N=6 ABJM and the N=8 BLG models. In the limit where the positions of adjacent operators become light-like, we find that the one-loop n-point correlator divided by its tree level expression coincides with a light-like n-polygon Wilson loop. Remarkably, the result can be simply expressed as a linear combination of five dimensional two-mass easy boxes. We manage to evaluate the integrals analytically and find a vanishing result, in agreement with previous findings for Wilson loops.Comment: 32 pages, 6 figures, JHEP

    On the infrared behaviour of 3d Chern-Simons theories in N=2 superspace

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    We discuss the problem of infrared divergences in the N=2 superspace approach to classically marginal three-dimensional Chern-Simons-matter theories. Considering the specific case of ABJM theory, we describe the origin of such divergences and offer a prescription to eliminate them by introducing non-trivial gauge-fixing terms in the action. We also comment on the extension of our procedure to higher loop order and to general three-dimensional Chern-Simons-matter models.Comment: 26 pages, 6 figures, JHEP3; v2: minor corrections and references added; v3: introduction expanded, presentation of section 3.3.1 improved, references added, version to appear in JHE

    On form factors in N=4 sym

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    In this paper we study the form factors for the half-BPS operators OI(n)\mathcal{O}^{(n)}_I and the N=4\mathcal{N}=4 stress tensor supermultiplet current WABW^{AB} up to the second order of perturbation theory and for the Konishi operator K\mathcal{K} at first order of perturbation theory in N=4\mathcal{N}=4 SYM theory at weak coupling. For all the objects we observe the exponentiation of the IR divergences with two anomalous dimensions: the cusp anomalous dimension and the collinear anomalous dimension. For the IR finite parts we obtain a similar situation as for the gluon scattering amplitudes, namely, apart from the case of WABW^{AB} and K\mathcal{K} the finite part has some remainder function which we calculate up to the second order. It involves the generalized Goncharov polylogarithms of several variables. All the answers are expressed through the integrals related to the dual conformal invariant ones which might be a signal of integrable structure standing behind the form factors.Comment: 35 pages, 7 figures, LATEX2

    The Omega Deformation, Branes, Integrability, and Liouville Theory

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    We reformulate the Omega-deformation of four-dimensional gauge theory in a way that is valid away from fixed points of the associated group action. We use this reformulation together with the theory of coisotropic A-branes to explain recent results linking the Omega-deformation to integrable Hamiltonian systems in one direction and Liouville theory of two-dimensional conformal field theory in another direction.Comment: 96 p

    A Systematic Review of Mosquito Coils and Passive Emanators: Defining Recommendations for Spatial Repellency Testing Methodologies.

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    Mosquito coils, vaporizer mats and emanators confer protection against mosquito bites through the spatial action of emanated vapor or airborne pyrethroid particles. These products dominate the pest control market; therefore, it is vital to characterize mosquito responses elicited by the chemical actives and their potential for disease prevention. The aim of this review was to determine effects of mosquito coils and emanators on mosquito responses that reduce human-vector contact and to propose scientific consensus on terminologies and methodologies used for evaluation of product formats that could contain spatial chemical actives, including indoor residual spraying (IRS), long lasting insecticide treated nets (LLINs) and insecticide treated materials (ITMs). PubMed, (National Centre for Biotechnology Information (NCBI), U.S. National Library of Medicine, NIH), MEDLINE, LILAC, Cochrane library, IBECS and Armed Forces Pest Management Board Literature Retrieval System search engines were used to identify studies of pyrethroid based coils and emanators with key-words "Mosquito coils" "Mosquito emanators" and "Spatial repellents". It was concluded that there is need to improve statistical reporting of studies, and reach consensus in the methodologies and terminologies used through standardized testing guidelines. Despite differing evaluation methodologies, data showed that coils and emanators induce mortality, deterrence, repellency as well as reduce the ability of mosquitoes to feed on humans. Available data on efficacy outdoors, dose-response relationships and effective distance of coils and emanators is inadequate for developing a target product profile (TPP), which will be required for such chemicals before optimized implementation can occur for maximum benefits in disease control

    The effectiveness of interventions to change six health behaviours: a review of reviews

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    Background: Several World Health Organisation reports over recent years have highlighted the high incidence of chronic diseases such as diabetes, coronary heart disease and cancer. Contributory factors include unhealthy diets, alcohol and tobacco use and sedentary lifestyles. This paper reports the findings of a review of reviews of behavioural change interventions to reduce unhealthy behaviours or promote healthy behaviours. We included six different health-related behaviours in the review: healthy eating, physical exercise, smoking, alcohol misuse, sexual risk taking (in young people) and illicit drug use. We excluded reviews which focussed on pharmacological treatments or those which required intensive treatments (e. g. for drug or alcohol dependency). Methods: The Cochrane Library, Database of Abstracts of Reviews of Effectiveness (DARE) and several Ovid databases were searched for systematic reviews of interventions for the six behaviours (updated search 2008). Two reviewers applied the inclusion criteria, extracted data and assessed the quality of the reviews. The results were discussed in a narrative synthesis. Results: We included 103 reviews published between 1995 and 2008. The focus of interventions varied, but those targeting specific individuals were generally designed to change an existing behaviour (e. g. cigarette smoking, alcohol misuse), whilst those aimed at the general population or groups such as school children were designed to promote positive behaviours (e. g. healthy eating). Almost 50% (n = 48) of the reviews focussed on smoking (either prevention or cessation). Interventions that were most effective across a range of health behaviours included physician advice or individual counselling, and workplace- and school-based activities. Mass media campaigns and legislative interventions also showed small to moderate effects in changing health behaviours. Generally, the evidence related to short-term effects rather than sustained/longer-term impact and there was a relative lack of evidence on how best to address inequalities. Conclusions: Despite limitations of the review of reviews approach, it is encouraging that there are interventions that are effective in achieving behavioural change. Further emphasis in both primary studies and secondary analysis (e.g. systematic reviews) should be placed on assessing the differential effectiveness of interventions across different population subgroups to ensure that health inequalities are addressed.</p

    Gaugino Anomaly Mediated SUSY Breaking: phenomenology and prospects for the LHC

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    We examine the supersymmetry phenomenology of a novel scenario of supersymmetry (SUSY) breaking which we call Gaugino Anomaly Mediation, or inoAMSB. This is suggested by recent work on the phenomenology of flux compactified type IIB string theory. The essential features of this scenario are that the gaugino masses are of the anomaly-mediated SUSY breaking (AMSB) form, while scalar and trilinear soft SUSY breaking terms are highly suppressed. Renormalization group effects yield an allowable sparticle mass spectrum, while at the same time avoiding charged LSPs; the latter are common in models with negligible soft scalar masses, such as no-scale or gaugino mediation models. Since scalar and trilinear soft terms are highly suppressed, the SUSY induced flavor and CP-violating processes are also suppressed. The lightest SUSY particle is the neutral wino, while the heaviest is the gluino. In this model, there should be a strong multi-jet +etmiss signal from squark pair production at the LHC. We find a 100 fb^{-1} reach of LHC out to m_{3/2}\sim 118 TeV, corresponding to a gluino mass of \sim 2.6 TeV. A double mass edge from the opposite-sign/same flavor dilepton invariant mass distribution should be visible at LHC; this, along with the presence of short-- but visible-- highly ionizing tracks from quasi-stable charginos, should provide a smoking gun signature for inoAMSB.Comment: 30 pages including 14 .eps figure

    Scattering in ABJ theories

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    We study the correspondence between scattering amplitudes and Wilson loops in three-dimensional Chern-Simons matter theories. In particular, using N=2 superspace formalism, we compute at one loop the whole spectrum of four-point superamplitudes for generic N>=2 supersymmetric theories and find a vanishing result for N=6 ABJ(M) and N=8 BLG models. This restricts the possible range of theories for which Wilson loops/scattering amplitudes duality might work. At two loops, we present the computation of the four-point ABJ scattering amplitude for external chiral superfields. Extending the known result for the ABJM Wilson loop to the ABJ case we find perfect agreement. We also discuss the dual conformal invariance of our results and the relationship between the Feynman diagram computation and unitarity methods. While for the ABJM theory dual conformally invariant integrals exactly reproduce the amplitude, for the ABJ case this happens only up to a residual constant depending on the parity-violating parameter. Finally we propose a BDS-like exponentiation for the amplitude based on an analogy with the four-dimensional N=4 SYM case, and discuss its strong coupling dual counterpart.Comment: 1+54 pages, 8 figure

    Formation of gutingimycin: analytical investigation of trioxacarcin A-mediated alkylation of dsDNA

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    Formation and fragmentation of recognition complexes between trioxacarcin A and various DNA sequences were examined by temperature-dependent UV and CD spectroscopy, HPLC analysis, and ESI mass spectrometry with regard to reaction conditions, intermediates, products, mechanism, and sequence specificity. Cleavage of the trioxacarcin–DNA complexes provided the natural product gutingimycin by guanine abstraction. The resulting DNA with an abasic site was further cleaved into a DNA fragment with a furanyl unit at the 3′-end and an oligonucleotide with a phosphorylated 5′-end

    Minimally helicity violating, maximally simple scalar amplitudes in N=4 SYM

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    In planar N=4 SYM we study a particular class of helicity preserving amplitudes. These are scalar amplitudes whose flavor configuration is chosen in such a way that only a limited number of diagrams is allowed, which exhibit an iterative structure. For such amplitudes we evaluate the tree level and one-loop contributions, providing a general formula valid for any number of particles. The ratio between the one-loop and tree level results is a simple combination of dual conformally invariant box functions with at most two massive legs. Along with the MHV and NMHV series, this constitutes the third known infinite sequence of one-loop amplitudes in N=4 SYM.Comment: 22 pages, 7 figures, published versio
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