19 research outputs found

    Integrable degenerate E\mathcal E-models from 4d Chern-Simons theory

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    We present a general construction of integrable degenerate E\mathcal E-models on a 2d manifold Σ\Sigma using the formalism of Costello and Yamazaki based on 4d Chern-Simons theory on Σ×CP1\Sigma \times \mathbb{C}P^1. We begin with a physically motivated review of the mathematical results of [arXiv:2008.01829] where a unifying 2d action was obtained from 4d Chern-Simons theory which depends on a pair of 2d fields hh and L\mathcal L on Σ\Sigma subject to a constraint and with L\mathcal L depending rationally on the complex coordinate on CP1\mathbb{C}P^1. When the meromorphic 1-form ω\omega entering the action of 4d Chern-Simons theory is required to have a double pole at infinity, the constraint between hh and L\mathcal L was solved in [arXiv:2011.13809] to obtain integrable non-degenerate E\mathcal E-models. We extend the latter approach to the most general setting of an arbitrary 1-form ω\omega and obtain integrable degenerate E\mathcal E-models. To illustrate the procedure we reproduce two well known examples of integrable degenerate E\mathcal E-models: the pseudo dual of the principal chiral model and the bi-Yang-Baxter σ\sigma-model

    A new example of the effects of a singular background on the zeta function

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    Para motivar nuestra discusión, consideramos un campo escalar dimensional 1 + 1 que interactúa con un fondo estático de tipo Coulomb, de modo que el espectro de fluctuaciones cuánticas está dado por un operador diferencial de segundo orden en una sola coordenada r con un coeficiente singular proporcional a 1 / r . Encontramos que las funciones espectrales de este operador presentan un comportamiento interesante: la función ζ tiene múltiples polos en el plano complejo; en consecuencia, aparecen logaritmos del tiempo adecuado en la expansión de trazas de calor. Como consecuencia, la función ζ no proporciona una regularización finita de la acción efectiva. Este trabajo amplía resultados similares previamente derivados en el contexto de singularidades cónicas.Fil: Falomir, Horacio Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Liniado, Joaquin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: González Pisani, Pablo Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentin

    Integrable Deformations from Twistor Space

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    Integrable field theories in two dimensions are known to originate as defect theories of 4d Chern-Simons and as symmetry reductions of the 4d anti-self-dual Yang-Mills equations. Based on ideas of Costello, it has been proposed in work of Bittleston and Skinner that these two approaches can be unified starting from holomorphic Chern-Simons in 6 dimensions. We provide the first complete description of this diamond of integrable theories for a family of deformed sigma models, going beyond the Dirichlet boundary conditions that have been considered thus far. Starting from 6d holomorphic Chern-Simons theory on twistor space with a particular meromorphic 3-form Ω\Omega, we construct the defect theory to find a novel 4d integrable field theory, whose equations of motion can be recast as the 4d anti-self-dual Yang-Mills equations. Symmetry reducing, we find a multi-parameter 2d integrable model, which specialises to the λ\lambda-deformation at a certain point in parameter space. The same model is recovered by first symmetry reducing, to give 4d Chern-Simons with generalised boundary conditions, and then constructing the defect theory.Comment: 38 pages, 1 figur

    Social protection to the informal sector: the role of minimum wage and income transfer policies

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    The objective of this study is to examine the impact that changes in minimum wage and the main income transfer programs have had on the economic participation of the population and the informal sector in Argentina. The obtained evidence suggests that modifications to minimum wage did not produce adverse effects on employment or have a substantial impact on the probabilities of entering the informal sector. Regarding the income transfers, it was possible to confirm that it did not encourage adults in beneficiary households to become economically inactive

    Antiinflammatory Therapy with Canakinumab for Atherosclerotic Disease

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    Background: Experimental and clinical data suggest that reducing inflammation without affecting lipid levels may reduce the risk of cardiovascular disease. Yet, the inflammatory hypothesis of atherothrombosis has remained unproved. Methods: We conducted a randomized, double-blind trial of canakinumab, a therapeutic monoclonal antibody targeting interleukin-1β, involving 10,061 patients with previous myocardial infarction and a high-sensitivity C-reactive protein level of 2 mg or more per liter. The trial compared three doses of canakinumab (50 mg, 150 mg, and 300 mg, administered subcutaneously every 3 months) with placebo. The primary efficacy end point was nonfatal myocardial infarction, nonfatal stroke, or cardiovascular death. RESULTS: At 48 months, the median reduction from baseline in the high-sensitivity C-reactive protein level was 26 percentage points greater in the group that received the 50-mg dose of canakinumab, 37 percentage points greater in the 150-mg group, and 41 percentage points greater in the 300-mg group than in the placebo group. Canakinumab did not reduce lipid levels from baseline. At a median follow-up of 3.7 years, the incidence rate for the primary end point was 4.50 events per 100 person-years in the placebo group, 4.11 events per 100 person-years in the 50-mg group, 3.86 events per 100 person-years in the 150-mg group, and 3.90 events per 100 person-years in the 300-mg group. The hazard ratios as compared with placebo were as follows: in the 50-mg group, 0.93 (95% confidence interval [CI], 0.80 to 1.07; P = 0.30); in the 150-mg group, 0.85 (95% CI, 0.74 to 0.98; P = 0.021); and in the 300-mg group, 0.86 (95% CI, 0.75 to 0.99; P = 0.031). The 150-mg dose, but not the other doses, met the prespecified multiplicity-adjusted threshold for statistical significance for the primary end point and the secondary end point that additionally included hospitalization for unstable angina that led to urgent revascularization (hazard ratio vs. placebo, 0.83; 95% CI, 0.73 to 0.95; P = 0.005). Canakinumab was associated with a higher incidence of fatal infection than was placebo. There was no significant difference in all-cause mortality (hazard ratio for all canakinumab doses vs. placebo, 0.94; 95% CI, 0.83 to 1.06; P = 0.31). Conclusions: Antiinflammatory therapy targeting the interleukin-1β innate immunity pathway with canakinumab at a dose of 150 mg every 3 months led to a significantly lower rate of recurrent cardiovascular events than placebo, independent of lipid-level lowering. (Funded by Novartis; CANTOS ClinicalTrials.gov number, NCT01327846.

    Algebraic Structure of Dirac Hamiltonians in Non-Commutative Phase Space

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    In this article we study two-dimensional Dirac Hamiltonians with non-commutativity both in coordinates and momenta from an algebraic perspective. In order to do so, we consider the graded Lie algebra sl(2∣1)\mathfrak{sl}(2|1) generated by Hermitian bilinear forms in the non-commutative dynamical variables and the Dirac matrices in 2+12+1 dimensions. By further defining a total angular momentum operator, we are able to express a class of Dirac Hamiltonians completely in terms of these operators. In this way, we analyze the energy spectrum of some simple models by constructing and studying the representation spaces of the unitary irreducible representations of the graded Lie algebra sl(2∣1)⊕so(2)\mathfrak{sl}(2|1)\oplus \mathfrak{so}(2). As application of our results, we consider the Landau model and a fermion in a finite cylindrical well.Comment: 22 page

    Car culture and countryside change

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    SIGLEAvailable from British Library Document Supply Centre-DSC:96/09701 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

    The National Trust Centenary Conference Proceedings

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    Conference held in Manchester (GB), 25-28 Sep 1995SIGLEAvailable from British Library Document Supply Centre- DSC:q96/00261 / BLDSC - British Library Document Supply CentreGBUnited Kingdo
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