Interacting dark sector with variable vacuum energy

We examine a cosmological scenario where dark matter is coupled to a variable vacuum energy while baryons and photons are two decoupled components for a spatially flat Friedmann-Robertson-Walker spacetime. We apply the $\chi^{2}$ method to the updated observational Hubble data for constraining the cosmological parameters and analyze the amount of dark energy in the radiation era. We show that our model fulfills the severe bound of $\Omega_{x}(z\simeq 1100)<0.009$ at the $2\sigma$ level, so it is consistent with the recent analysis that includes cosmic microwave background anisotropy measurements from the Planck survey, the Atacama Cosmology Telescope, and the South Pole Telescope along with the future constraints achievable by the Euclid and CMBPol experiments, and fulfills the stringent bound $\Omega_{x}(z\simeq 10^{10})<0.04$ at the $2\sigma$ level in the big-bang nucleosynthesis epoch.Comment: 5 pages,3 figures, 2 tables. (http://prd.aps.org/abstract/PRD/v88/i8/e087301

Symmetry limit properties of a priori mixing amplitudes for non-leptonic and weak radiative decays of hyperons

We show that the so-called parity-conserving amplitudes predicted in the a priori mixing scheme for non-leptonic and weak radiative decays of hyperons vanish in the strong-flavor symmetry limit

Mirror matter admixtures in K_S to gamma gamma

The latest measurement of the K_S to gamma gamma branching ratio clearly shows an enhancement over the current theoretical prediction. As in other K and B meson decays, this invites to consider the possibility of the contribution of new physics. We study a particular form of the latter, which may be referred to as manifest mirror symmetry. The experimental data are described using previously determined values for the mixing angles of the admixtures of mirror matter in ordinary hadrons and by assuming that for pi^0, eta, eta', the mirror decay amplitudes have the same magnitudes as their ordinary counterparts

The complex structure of HH 110 as revealed from Integral Field Spectroscopy

HH 110 is a rather peculiar Herbig-Haro object in Orion that originates due to the deflection of another jet (HH 270) by a dense molecular clump, instead of being directly ejected from a young stellar object. Here we present new results on the kinematics and physical conditions of HH 110 based on Integral Field Spectroscopy. The 3D spectral data cover the whole outflow extent (~4.5 arcmin, ~0.6 pc at a distance of 460 pc) in the spectral range 6500-7000 \AA. We built emission-line intensity maps of H$\alpha$, [NII] and [SII] and of their radial velocity channels. Furthermore, we analysed the spatial distribution of the excitation and electron density from [NII]/H$\alpha$, [SII]/H$\alpha$, and [SII] 6716/6731 integrated line-ratio maps, as well as their behaviour as a function of velocity, from line-ratio channel maps. Our results fully reproduce the morphology and kinematics obtained from previous imaging and long-slit data. In addition, the IFS data revealed, for the first time, the complex spatial distribution of the physical conditions (excitation and density) in the whole jet, and their behaviour as a function of the kinematics. The results here derived give further support to the more recent model simulations that involve deflection of a pulsed jet propagating in an inhomogeneous ambient medium. The IFS data give richer information than that provided by current model simulations or laboratory jet experiments. Hence, they could provide valuable clues to constrain the space parameters in future theoretical works.Comment: 12 pages, 15 figures Accepted in MNRA

A Mathematical Model to Study the Meningococcal Meningitis

AbstractThe main goal of this work is to introduce a novel mathematical model to study the spreading of meningococcal meningitis. Specifically, it is a discrete mathematical model based on cellular automata where the population is divided in five classes: sus- ceptible, asymptomatic infected, infected with symptoms, carriers, recovered and died. It catches the individual characteristics of people in order to give a prediction of both the individual behavior, and whole evolution of population

MS-222 toxicity in juvenile seabream correlates with diurnal activity, as measured by a novel video-tracking method

©2010. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/ This document is the Accepted version of a Published Work that appeared in final form in Aquaculture. To access the final edited and published work see https://doi.org/10.1016/j.aquaculture.2010.06.028Fish are frequently exposed to anaesthetics since their use is necessary in several aquaculture procedures. The aim of this study was to investigate the existence of day night differences in toxicity and effectiveness of a common fish anaesthetic (MS-222) in juvenile gilthead seabream (Sparus aurata), determining the induction time of anaesthesia and subsequent recovery by a novel video-recording system. Our results showed that MS-222 toxicity was significantly higher at ML (mid-light) (LC50=85.5 mg/L) than at MD (mid-darkness) (LC50=107.6 mg/L) (trimmed Spearman-Karber method). In addition, when fish were exposed to a sublethal but effective MS-222 concentration (65 mg/L), 7 min passed before 50% a reduction in swimming activity was observed at ML compared to the 9 min required at MD. As regards recovery, fish showed activity levels similar to basal levels 10 min after MS-222 removal at ML, but only 6 min at MD. These results indicated that both toxicity and effectiveness were higher during the day than at night, coinciding with the diurnal activity pattern displayed by seabream, which should be taken into account when designing and applying daily protocols for anaesthesia in aquacultur

Mirror matter admixtures in K_L \to \gamma\gamma

Based on possible albeit tiny, admixtures of mirror matter in ordinary mesons we study the K_L \to \gamma\gamma transition. We find that this process can be described with a small SU(3) symmetry breaking of only 3%. We also determine the eta-eta' mixing angle and the pseudoscalar decay constants. The results for these parameters are consistent with some obtained in the literature. They favor two recent determinations; one based on two analytical constraints, and another one based on next-to-leading order power corrections

El Service-Learning o Aprendizaje-Servicio como método de enseñanza: experiencia de la Pace University (Nueva York) en la creación de Green Maps o Mapas Verdes en el marco del desarrollo sostenible del turismo

El trabajo se centra en el Service-Learning o Aprendizaje-Servicio como método de enseñanza innovador. Como ejemplo de su aplicación presentamos los proyectos internacionales puestos en marcha en los estudios de Turismo de la Pace University (Nueva York) para la creación de green maps o mapas verdes de comunidades locales en el marco del Desarrollo Sostenible del Turismo.This paper focuses on Service-Learning as an innovative teaching method. As an example of its application, we present the international projects initiated by Pace University Tourism students for the creation of Green Maps of local communities in order to contribute towards Sustainable Tourism Development