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

Finite-temperature properties of frustrated classical spins coupled to the lattice

We present extensive Monte Carlo simulations for a classical antiferromagnetic Heisenberg model with both nearest ($J_1$) and next-nearest ($J_2$) exchange couplings on the square lattice coupled to the lattice degrees of freedom. The Ising-like phase transition, that appears for $J_2/J_1>1/2$ in the pure spin model, is strengthened by the spin-lattice coupling, and is accompanied by a lattice deformation from a tetragonal symmetry to an orthorhombic one. Evidences that the universality class of the transition does not change with the inclusion of the spin-lattice coupling are reported. Implications for ${\rm Li_2VOSiO_4}$, the prototype for a layered $J_1{-}J_2$ model in the collinear regime, are also discussed.Comment: 6 pages and 8 figure

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

Monetary policy and inflation persistence in the Eurozone

The primary goal of the European Central Bank’s (ECB) monetary policy is to achieve price stability. Whereas during the 1980s and 1990s there was a rapid and strong convergence in terms of price differential among the Euro countries, particularly in those countries with higher inflation rates in the past, single monetary policy has proved to be quite inefficient in continuing this trend and has not achieved further reductions in inflation rate differentials within the euro zone. Since the ECB sets the official interest rate according to the average inflation of the euro area, the persistence of such price differentials within the area would mean that the “one size interest rate policy” would not fit all. This paper studies empirically the inflation rate differentials and their persistence in some currency unions with the aim to draw some conclusions for the working of the ECB monetary policy. KEYWORDS: monetary policy; inflation persistence; currency unions

Ising transition driven by frustration in a 2D classical model with SU(2) symmetry

We study the thermal properties of the classical antiferromagnetic Heisenberg model with both nearest ($J_1$) and next-nearest ($J_2$) exchange couplings on the square lattice by extensive Monte Carlo simulations. We show that, for $J_2/J_1 > 1/2$, thermal fluctuations give rise to an effective $Z_2$ symmetry leading to a {\it finite-temperature} phase transition. We provide strong numerical evidence that this transition is in the 2D Ising universality class, and that $T_c\to 0$ with an infinite slope when $J_2/J_1\to 1/2$.Comment: 4 pages with 4 figure

Métodos de fertilización para rendimiento comercial en tres cultivares de ajo (Allium sativum L.)

Garlic (Allium sativum L.) is an important crop for domestic consumption in Peru. However, there is insufficient information available on crop management, particularly on fertiliser application to local cultivars. In order to evaluate the response of three garlic cultivars to three fertilisation methods, an experiment was conducted at the Donoso Experimental Station in Huaral district, a province of Lima. Three garlic cultivars were used as experimental materials: ‘Cincomesino’, ‘Arequipeño 14’ and ‘Margosino’. Three methods of fertilisation were applied as treatments: broadcast application before furrowing (M1), fertilisation in a superficial groove or false furrow (M2), and fertilisation in the lateral furrows, or band application (M3). The experiments were installed in three parcels for each cultivar, with a randomised complete block design for each parcel and four replications. In general, localised fertilisation methods showed the best performance for the broadcast method. Regarding total yield, fertilisation at the sides of the furrow (M3) for ‘Cincomesino’ reached 13.08 t/ha. The highest yield for the ‘Arequipeño 14’ cultivar (12.25 t/ha) was achieved using fertilisation with a surface groove or false furrow (M2). For the ‘Margosino’ cultivar, fertilisation on the sides of the furrow was ideal, and the yield was 10.95 t/ha

From sport to deporte: a discussion etymological, semantic and conceptual in the spanish laguage

En la lengua castellana la palabra deporte, plantea de entrada una triple discusión: de carácter etimológico, semántico y conceptual. Este es el objeto de estudio de este artículo analizar los precedentes históricos de la palabra deporte y trazar su evolución hasta desembocar en el término actual, desde este enfoque trinitario. Para ello nos basamos en la recuperación de fuentes documentales originales, algunas de ellas inéditas y otras poco conocidas o consideradas, que nos permitan adquirir nuevos conocimientos y nos obligan a reinterpretar y corregir algunas afirmaciones actuales.In Spanish, the word deporte (sport) raises a debate that is three-fold: etymological, semantic and conceptual. The study object of this article is to analize the historical precedents of the word deporte and to trace its evolution up to the present day term, from this trinitarian approach. For this purpose, we based our work on recovering original documentary sources, some of which were unpublished, other were little known or rarely considered. The aim is for these sources to allow us to acquire new knowledge and force us to reinterpret and correct some current claim

Invertebrate vasopressin/oxytocin homologs: characterization of peptides from Conus geographus and Conus striatus venoms

Journal ArticleThe vasopressin-oxytocin family of peptides is of very ancient lineage, found in organisms as diverse as hydra and man. Although these peptides have been intensively studied in vertebrates, the presumably more extensive invertebrate series was defined primarily by immunological methods. In this report, we describe the purification and structures of two peptides of the vasopressin-oxytocin family from molluscs ("Conopressins"), which were found in the venom of fish-hunting marine snails of the genus Conus