Fluctuations around classical solutions for gauge theories in Lagrangian and Hamiltonian approach

We analyze the dynamics of gauge theories and constrained systems in general under small perturbations around a classical solution (background) in both Lagrangian and Hamiltonian formalisms. We prove that a fluctuations theory, described by a quadratic Lagrangian, has the same constraint structure and number of physical degrees of freedom as the original non-perturbed theory, assuming the non-degenerate solution has been chosen. We show that the number of Noether gauge symmetries is the same in both theories, but that the gauge algebra in the fluctuations theory becomes Abelianized. We also show that the fluctuations theory inherits all functionally independent rigid symmetries from the original theory, and that these symmetries are generated by linear or quadratic generators according to whether the original symmetry is preserved by the background, or is broken by it. We illustrate these results with the examples.Comment: 27 pages; non-essential but clarifying changes in Introduction, Sec. 3 and Conclusions; the version to appear in J.Phys.

Inhibition of Escherichia coli chemotaxis by omega-conotoxin, a calcium ion channel blocker

Escherichia coli chemotaxis was inhibited by omega-conotoxin, a calcium ion channel blocker. With Tris-EDTA-permeabilized cells, nanomolar levels of omega-conotoxin inhibited chemotaxis without loss of motility. Cells treated with omega-conotoxin swam with a smooth bias, i.e., tumbling was inhibited

Topological regularization and self-duality in four-dimensional anti-de Sitter gravity

It is shown that the addition of a topological invariant (Gauss-Bonnet term) to the anti-de Sitter (AdS) gravity action in four dimensions recovers the standard regularization given by holographic renormalization procedure. This crucial step makes possible the inclusion of an odd parity invariant (Pontryagin term) whose coupling is fixed by demanding an asymptotic (anti) self-dual condition on the Weyl tensor. This argument allows to find the dual point of the theory where the holographic stress tensor is related to the boundary Cotton tensor as $T_{j}^{i}=\pm (\ell ^{2}/8\pi G)C_{j}^{i}$, which has been observed in recent literature in solitonic solutions and hydrodynamic models. A general procedure to generate the counterterm series for AdS gravity in any even dimension from the corresponding Euler term is also briefly discussed.Comment: 13 pages, no figures; enlarged discussion on self-duality condition for AAdS spacetimes, references added, final version for PR

Quantum Statistical Relation for black holes in nonlinear electrodynamics coupled to Einstein-Gauss-Bonnet AdS gravity

We consider curvature-squared corrections to Einstein-Hilbert gravity action in the form of Gauss-Bonnet term in D>4 dimensions. In this theory, we study the thermodynamics of charged static black holes with anti-de Sitter (AdS) asymptotics, and whose electric field is described by nonlinear electrodynamics (NED). These objects have received considerable attention in recent literature on gravity/gauge dualities. It is well-known that, within the framework of anti de-Sitter/Conformal Field Theory (AdS/CFT) correspondence, there exists a nonvanishing Casimir contribution to the internal energy of the system, manifested as the vacuum energy for global AdS spacetime in odd dimensions. Because of this reason, we derive a Quantum Statistical Relation directly from the Euclidean action and not from the integration of the First Law of thermodynamics. To this end, we employ a background-independent regularization scheme which consists in the addition to the bulk action of counterterms that depend on both extrinsic and intrinsic curvatures of the boundary (Kounterterm series). This procedure results in a consistent inclusion of the vacuum energy and chemical potential in the thermodynamic description for Einstein-Gauss-Bonnet AdS gravity regardless the explicit form of the NED Lagrangian.Comment: 22 pages, no figures; 3 references and a subsection on Thermodynamic Charges added; Final version for PR

Metabolismo de PUFAs de origen vegetal en carne de carpa herbívora

En los últimos años, el estudio de los PUFAs, pertenecientes a la familia de los omega 3, adquirió gran importancia. Es por eso que se plantea como alternativa aumentar el contenido de los mismos en productos como la carne de C. idella a partir de la alimentación con forrajes verdes como Lolium multiflorum. El objetivo de este trabajo es determinar la capacidad de C. idella para metabolizar el ácido linolenico presente en L. multiflorum y de acumularlo en carne en forma de ác. eicosapentaenoico (EPA) y docosahexaenoico (DHA) Relacionar el contenido de ALA presente en L. multiflorum y el contenido de ALA, EPA y DHA en la carne de C. idellaÁrea: Ciencias Agrícolas, Produccion y Salud Anima

Microesferas de quitosano como potenciales transportadores de ácidos nucleicos y otros bioactivos

En este trabajo se prepararon microesferas de quitosano cargadas con ADN comercial como prototipo de sistemas de liberación de ácidos nucleicos. Para preparar las microesferas se utilizó una metodología basada en la preparación de una emulsión agua en aceite (w/o) seguida de entrecruzamiento con glutaraldehído. Las microesferas producidas fueron caracterizadas desde un punto de vista morfológico (HRSEM), evaluadas en cuanto al tamaño (SEM y citometría de flujo) y utilizadas para determinar el perfil de descarga de ADN. Se obtuvieron microesferas con una estructura porosa y con tamaño entre 1 y 20 μm de diámetro (SEM), destacándose una población de partículas individualizadas alrededor de 45% (en número) entre las 6 y 12 μm, según los datos aportados por la citometría de flujo. En cuanto al perfil de liberación en medio a valor de pH fisiológico se observó una liberación rápida, siendo que durante la primera hora 85% del principio activo había sido liberado alcanzándose 100% al final de dos horas.Ação bilateral de intercâmbio de docentes IPB/UDELAR (Proyecto 720)

Origen e institucionalización del asociacionismo gimnástico-deportivo en España en el siglo XIX (1822-1900)

Este estudio aborda el nacimiento y desarrollo del asociacionismo gimnástico-deportivo en España en el siglo xix desde 1822 año en el que aparecieron las primeras asociaciones deportivas hasta 1900. Este proceso contribuye al ordenamiento institucional del deporte, a su difusión y a su legitimación social. El asociacionismo deportivo se inició de forma titubeante pero despegó a partir de 1875. La introducción del deporte coincidió con la Restauración borbónica y el fervor de los reyes y la aristocracia por el modelo cultural inglés y el sport, y fue sostenida por el Regeneracionismo y la Institución Libre de Enseñanza. Para construir la lista de entidades que conforman el deporte institucionalizado, se han seguido tres procesos, que beben de fuentes primarias y secundarias. En primer lugar se ha realizado una exhaustiva revisión documental de los trabajos anteriores de dos de los autores. A continuación, se han efectuado búsquedas sistematizadas en las principales plataformas documentales digitalizadas de España. Finalmente, se han contrastado los datos resultantes con los últimos trabajos historiográficos del período. Este proceso metodológico de tres partes produjo una lista de 363 entidades deportivas ubicadas en las zonas más acomodadas e industrializadas. El ciclismo fue el deporte que atrajo mayor número de asociaciones. Los resultados de la investigación muestran la vigorosidad del proceso de institucionalización del deporte en España en el siglo xix y su arraigo inicial entre las capas aristocráticas y burguesas

Couplings between Chern-Simons gravities and 2p-branes

The interaction between Chern-Simons (CS) theories and localized external sources (2p-branes) is analyzed. This interaction generalizes the minimal coupling between a point charge (0-brane) and a gauge connection. The external currents that define the 2p-branes are covariantly constant (D-2p-1)-forms coupled to (2p-1) CS forms. The general expression for the sources --charged with respect to the corresponding gauge algebra-- is presented, focusing on two special cases: 0-branes and (D-3)-branes. In any dimension, 0-branes are constructed as topological defects produced by a surface deficit of (D-2)-sphere in AdS space, and they are not constant curvature spaces for D>3. They correspond to dimensionally continued black holes with negative mass. On the other hand, in the case of CS (super) gravities, the (D-3)-branes are naked conical singularities (topological defects) obtained by identification of points with a Killing vector. In 2+1 dimensions, extremal spinning branes of this type are BPS states. Stable (D-3)-branes are shown to exist also in higher dimensions, as well. Classical field equations are also discussed and in the presence of sources there is a large number of inequivalent and disconnected sectors in solution space.Comment: 29 pages, no figures; version accepted in PRD; extended introduction and several references added; some sections have been reorganized and several minor corrections mad

Global Inhibition of DC Priming Capacity in the Spleen of Self-Antigen Vaccinated Mice Requires IL-10

DC in the spleen are highly activated following intravenous vaccination with a foreign antigen, promoting expansion of effector T cells, but remain phenotypically and functionally immature after vaccination with a self-antigen. Up-regulation or suppression of expression of a cohort of pancreatic enzymes 24-72 hours post-vaccination can be used as a biomarker of stimulatory versus toleragenic DC, respectively. Here we show, using MUC1 transgenic mice (MUC1.Tg) and a vaccine based on the MUC1 peptide which these mice perceive as a self-antigen, that the difference in enzyme expression that predicts whether DC will promote immune response or immune tolerance, is seen as early as 4-8 hours following vaccination. We also identify early production of IL-10 as a predominant factor that both correlates with this early time point and controls DC function. Pre-treating mice with an antibody against the IL-10 receptor (IL-10R) prior to vaccination results in DC that up-regulate CD40, CD80, and CD86 and promote stronger IFNγ+ T cell responses. This study suggests that transient inhibition of IL-10 prior to vaccination could improve responses to cancer vaccines that utilize self-tumor antigens