Energy associated with charged dilaton black holes

It is known that certain properties of charged dilaton black holes depend on a free parameter $\beta$ which controls the strength of the coupling of the dilaton to the Maxwell field. We obtain the energy associated with static spherically symmetric charged dilaton black holes for arbitrary value of the coupling parameter and find that the energy distribution depends on the value of $\beta$. With increasing radial distance, the energy in a sphere increases for $\beta = 0$ as well as for $\beta 1$, and remains constant for $\beta = 1$. However, the total energy turns out to be the same for all values of $\beta$.Comment: singlespaced 7 pages, LaTex, no figures, misprints corrected, to appear in Int. J. Mod. Phys.

Nonlinear interfaces: intrinsically nonparaxial regimes and effects

The behaviour of optical solitons at planar nonlinear boundaries is a problem rich in intrinsically nonparaxial regimes that cannot be fully addressed by theories based on the nonlinear Schrödinger equation. For instance, large propagation angles are typically involved in external refraction at interfaces. Using a recently proposed generalized Snell's law for Helmholtz solitons, we analyse two such effects: nonlinear external refraction and total internal reflection at interfaces where internal and external refraction, respectively, would be found in the absence of nonlinearity. The solutions obtained from the full numerical integration of the nonlinear Helmholtz equation show excellent agreement with the theoretical predictions

Universal quantum computation with the Orbital Angular Momentum of a single photon

We prove that a single photon with quantum data encoded in its orbital angular momentum can be manipulated with simple optical elements to provide any desired quantum computation. We will show how to build any quantum unitary operator using beamsplitters, phase shifters, holograms and an extraction gate based on quantum interrogation. The advantages and challenges of these approach are then discussed, in particular the problem of the readout of the results.Comment: First version. Comments welcom

Energy Distribution of a Charged Regular Black Hole

We calculate the energy distribution of a charged regular black hole by using the energy-momentum complexes of Einstein and M{\o}ller.Comment: 6 pages, no figure

Helmholtz bright and boundary solitons

We report, for the first time, exact analytical boundary solitons of a generalized cubic-quintic Non-Linear Helmholtz (NLH) equation. These solutions have a linked-plateau topology that is distinct from conventional dark soliton solutions; their amplitude and intensity distributions are spatially delocalized and connect regions of finite and zero wave-field disturbances (suggesting also the classification as 'edge solitons'). Extensive numerical simulations compare the stability properties of recently-reported Helmholtz bright solitons, for this type of polynomial non-linearity, to those of the new boundary solitons. The latter are found to possess a remarkable stability characteristic, exhibiting robustness against perturbations that would otherwise lead to the destabilizing of their bright-soliton counterpart

Utilización de los polifenoles de la uva en la alimentación de las aves

In the last few years there is a growing interest in the antioxidant and antimicrobial properties of several polyphenols, especially flavonoids, which are present in several plants. Wine industry by- products (grape pomace, skin and seeds) and wine polyphenols extracts contain a wide range of these phenolic compounds. The functional properties of these polyphenols could be useful and applicable in animal nutrition. These effects have not been studied in chickens. Recent studies have shown that dietary inclusion of these grape by-products in broilers increased the oxidative stability of chicken meat in similar way that those obtained with the addition of Vitamin E. By the other hand, the use of these by-products has also been associated with a favourable modification of the intestinal microbiota by reducing the presence of several harmful bacteria and favouring other beneficial bacteEn los últimos años ha cobrado especial interés la capacidad antioxidante y antimicrobiana que poseen determinados polifenoles, especialmente flavonoides, presentes en diferentes vegetales. Los subproductos de la industria del vino (orujo, hollejo y granilla) y los extractos de polifenoles de uva poseen una amplia variedad de estos compuestos polifenólicos. Las propiedades funcionales de estos compuestos podrían ser de gran utilidad y aplicación en alimentación animal. Estos efectos han sido muy poco estudiados en aves. Estudios recientemente publicados con la incorporación de los subproductos de la uva en las raciones de las aves demuestran una mejora en la estabilidad oxidativa de los productos cárnicos del pollo similares a los obtenidos con la adición de la vitamina E. Por otro lado, su incorporación también se ha asociado con una modificación favorable de la microbiota intestinal reduciendo la presencia de determinadas bacterias perjudiciales y favoreciendo algunas bacterias beneficiosas