The Herschel view of GAS in Protoplanetary Systems (GASPS): First comparisons with a large grid of models

The Herschel GASPS key program is a survey of the gas phase of protoplanetary discs, targeting 240 objects which cover a large range of ages, spectral types, and disc properties. To interpret this large quantity of data and initiate self-consistent analyses of the gas and dust properties of protoplanetary discs, we have combined the capabilities of the radiative transfer code MCFOST with the gas thermal balance and chemistry code ProDiMo to compute a grid of ≈300  000 disc models (DENT). We present a comparison of the first Herschel/GASPS line and continuum data with the predictions from the DENT grid of models. Our objective is to test some of the main trends already identified in the DENT grid, as well as to define better empirical diagnostics to estimate the total gas mass of protoplanetary discs. Photospheric UV radiation appears to be the dominant gas-heating mechanism for Herbig stars, whereas UV excess and/or X-rays emission dominates for T Tauri stars. The DENT grid reveals the complexity in the analysis of far-IR lines and the difficulty to invert these observations into physical quantities. The combination of Herschel line observations with continuum data and/or with rotational lines in the (sub-)millimetre regime, in particular CO lines, is required for a detailed characterisation of the physical and chemical properties of circumstellar discs

Nonleptonic two-body B-decays including axial-vector mesons in the final state

We present a systematic study of exclusive charmless nonleptonic two-body B decays including axial-vector mesons in the final state. We calculate branching ratios of B\to PA, VA and AA decays, where A, V and P denote an axial-vector, a vector and a pseudoscalar meson, respectively. We assume naive factorization hypothesis and use the improved version of the nonrelativistic ISGW quark model for form factors in B\to A transitions. We include contributions that arise from the effective \Delta B=1 weak Hamiltonian H_{eff}. The respective factorized amplitude of these decays are explicitly showed and their penguin contributions are classified. We find that decays B^-to a_1^0\pi^-,\barB^0\to a_1^{\pm}\pi^{\mp}, B^-\to a_1^-\bar K^0, \bar B^0\to a_1^+K^-, \bar B^0\to f_1\bar K^0, B^-\to f_1K^-, B^-\to K_1^-(1400)\etap, B^-\to b_1^-\bar K^{0}, and \bar B^0\to b_1^+\pi^-(K^-) have branching ratios of the order of 10^{-5}. We also study the dependence of branching ratios for B \to K_1P(V,A) decays (K_1=K_1(1270),K_1(1400)) with respect to the mixing angle between K_A and K_B.Comment: 28 pages, 2 tables and one reference added, notation changed in appendices, some numerical results and abstract correcte

Enfriamiento hidrónico de la masa térmica del concreto

This article features an analysis of the active radiant hydronic system as a thermic mass cooling system of concrete and the time which this cooling process is being made on the sub-humid mild climate temperature (Mexico City, Mexico) and the warm humid climate temperature (San Pedro Sula, Honduras). The research develop two concrete prototypes, a hydronic system and the another one as a reference to compare the system functionality. On Mexico City’s weather, the concrete thermic mass diminishes 6.73 °C in comparison with the environment temperature. At San Pedro Sula, the concrete thermic mass diminishes 3.32°C in comparison with the environment temperature as well. Reason why this system’s functions works better on sub-humid mild climate temperature because of the high dew temperature is lower than the warm humid climate temperature, so that the water temperature circulation is lower, leveling up the heat absorption from the concrete thermic mass.El presente artículo realiza un análisis del sistema hidrónico radiante activo como sistema de enfriamiento de la masa térmica del concreto y en cuanto tiempo se realiza dicho enfriamiento en clima templado subhúmedo (ciudad de México, México) y en clima cálido húmedo (ciudad de San Pedro Sula, Honduras). En la investigación se realiza dos prototipos de concreto, uno con el sistema hidrónico y el otro como referencia, para comparar el funcionamiento del sistema. En el clima de la Ciudad de México, la masa térmica del concreto disminuyó 6.73°C con respecto a la temperatura del ambiente. En la ciudad de San Pedro Sula, la masa térmica del concreto disminuyó 3.32°C con respecto a la temperatura del ambiente. Por lo que el sistema posee un mejor funcionamiento en clima templado subhúmedo debido a que la temperatura de rocío es más baja que en clima cálido-húmedo, por lo que la temperatura del agua para la circulación del sistema es menor, incrementando la absorción del calor de la masa térmica del concreto