A photometric comprehensive study of circumnuclear star forming rings: the sample

We present photometry in U, B, V, R and I continuum bands and in H$\alpha$ and H$\beta$ emission lines for a sample of 336 circumnuclear star forming regions (CNSFR) located in early type spiral galaxies with different levels of activity in their nuclei. They are nearby galaxies, with distances less than 100 Mpc, 60\% of which are considered as interacting objects. This survey of 20 nuclear rings aims to provide insight into their star formation properties as age, stellar population and star formation rate. Extinction corrected H$\alpha$ luminosities range from $1.3\times 10^{38}$ to $4\times 10^{41} erg s^{-1}$, with most of the regions showing values between 39.5 $\leq log L(H\alpha) \leq$ 40, which implies masses for the ionizing clusters higher than $2\times 10^{5} M_\odot$. H$\alpha$ and H$\beta$ images have allowed us to obtain an accurate measure of extinction. We have found an average value of A$_V$ = 1.85 magnitudes. (U-B) colour follows a two maximum distribution around (U-B)$\simeq$ -0.7, and -0.3; (R-I) also presents a bimodal behaviour, with maximum values of 0.6 and 0.9. Reddest (U-B) and (R-I) regions appear in non-interacting galaxies. Reddest (R-I) regions lie in strongly barred galaxies. For a significant number of HII regions the observed colours and equivalent widths are not well reproduced by single burst evolutionary theoretical models.Comment: Accepted for publication in MNRAS. Accepted 15 May 2015. Received, 21 April 201

National institutions, stakeholder engagement, and firms' environmental, social, and governance performance

This paper studies the influence of different national institutions on corporate environmental, social, and governance (ESG) performance through the varieties of institutional systems approach. This research complements previous research that used traditional approaches such as the national business systems and the varieties of capitalism, because it considers companies in understudied economies in Asia, Africa, Eastern Europe, the Middle East, and Latin America. To that aim, a dataset of 4, 751 firms within 52 countries is examined through a multilevel model, which allows establishing three levels of analysis: (a) yearly observations of a firm ESG performance, (b) the companies, and (c) the countries. This technique is useful to address the nested nature of firms' ESG performance within higher level institutional contexts. The results identify which specific national institutions enhance/restrict companies' ESG performance. This provides interesting implications because firms' ESG represent most of the companies' contributions to environmental preservation, social well-being, and community development

Nonparametric Bayesian Mixed-effect Model: a Sparse Gaussian Process Approach

Multi-task learning models using Gaussian processes (GP) have been developed and successfully applied in various applications. The main difficulty with this approach is the computational cost of inference using the union of examples from all tasks. Therefore sparse solutions, that avoid using the entire data directly and instead use a set of informative "representatives" are desirable. The paper investigates this problem for the grouped mixed-effect GP model where each individual response is given by a fixed-effect, taken from one of a set of unknown groups, plus a random individual effect function that captures variations among individuals. Such models have been widely used in previous work but no sparse solutions have been developed. The paper presents the first sparse solution for such problems, showing how the sparse approximation can be obtained by maximizing a variational lower bound on the marginal likelihood, generalizing ideas from single-task Gaussian processes to handle the mixed-effect model as well as grouping. Experiments using artificial and real data validate the approach showing that it can recover the performance of inference with the full sample, that it outperforms baseline methods, and that it outperforms state of the art sparse solutions for other multi-task GP formulations.Comment: Preliminary version appeared in ECML201

The Stationary Phase Method for a Wave Packet in a Semiconductor Layered System. The applicability of the method

Using the formal analysis made by Bohm in his book, {\em "Quantum theory"}, Dover Publications Inc. New York (1979), to calculate approximately the phase time for a transmitted and the reflected wave packets through a potential barrier, we calculate the phase time for a semiconductor system formed by different mesoscopic layers. The transmitted and the reflected wave packets are analyzed and the applicability of this procedure, based on the stationary phase of a wave packet, is considered in different conditions. For the applicability of the stationary phase method an expression is obtained in the case of the transmitted wave depending only on the derivatives of the phase, up to third order. This condition indicates whether the parameters of the system allow to define the wave packet by its leading term. The case of a multiple barrier systems is shown as an illustration of the results. This formalism includes the use of the Transfer Matrix to describe the central stratum, whether it is formed by one layer (the single barrier case), or two barriers and an inner well (the DBRT system), but one can assume that this stratum can be comprise of any number or any kind of semiconductor layers.Comment: 15 pages, 4 figures although figure 4 has 5 graph

La Casa de correcció de Barcelona sota la direcció de J. M. Canalejas (1858-1863)

L'article se centra en la descripció del funcionament intern i el mètode de reeducació utilitzat a la casa de correcció de Barcelona durant els anys 1858-1863, període en el qual la institució fou guiada de la mà de José María Canalejas, un militar que va saber posar la institució a l'alçada dels millors establiments correccionals d'Europa. Prèviament a la descripció d'aquest període, s'al·ludeix a la problemàtica de la delinqüència infantil i juvenil durant la primera meitat del XIX —marc que serveix per entendre el perquè de la creació de les cases de correcció en aquell moment històric— i es perfila l'evolució de la casa de correcció barcelonesa fins al nomenament de Canalejas com a director d'aquesta.The article focuses on the description of the internal functioning and the re-educational model in the correctional house of Barcelona during the years 1858-1863, period where the institution was led by José María Canalejas, a military man who was able to put the institution up to the same level as the best correctional institutions in Europe. Previously to the description of this period, the problem of child delinquency during the first half of the 19th century is mentioned —setting that will help understand why the correctional houses were instituted in that particular historical moment— and the evolution of the Barcelona Correctional House until the nomination of Canalejas as its director is outlined