PopStar Evolutionary Synthesis Models II: Optical emission-line spectra from Giant H{\sc ii} regions

This is the second paper of a series reporting the results from the PopStar evolutionary synthesis models. Here we present synthetic emission line spectra of H{\sc ii} regions photoionized by young star clusters, for seven values of cluster masses and for ages between 0.1 and 5.2 Myr. The ionizing Spectral Energy Distributions (SEDs) are those obtained by the PopStar code \citep*{mgb09} for six different metallicities, with a very low metallicity set, Z=0.0001, not included in previous similar works. We assume that the radius of the H{\sc ii} region is the distance at which the ionized gas is deposited by the action of the mechanical energy of the winds and supernovae from the central ionizing young cluster. In this way the ionization parameter is eliminated as free argument, since now its value is obtained from the cluster physical properties (mass, age and metallicity) and from the gaseous medium characteristics (density and abundances). We discuss our results and compare them with those from previous models and also with a large and data set of giant H{\sc ii} regions for which abundances have been derived in a homogeneous manner. The values of the [OIII] lines (at $\lambda\lambda$ 4363, 4959, 5007\AA) in the lowest metallicity nebulae are found to be very weak and similar to those coming from very high metallicity regions (solar or over-solar). Thus, the sole use of the oxygen lines is not enough to distinguish between very low and very high metallicity regions. In these cases we emphasize the need of the additional support of alternative metallicity tracers, like the [SIII] lines in the near-\textit{IR}.Comment: 20 pages, 26 figures, accepted for publication in MNRAS Main Journa

Agrupación robusta de Bancos en Argentina

The purpose of this paper is to classify and characterize 64 banks, active as of 2010 in Argentina, by means of robust techniques used on information gathered during the period 2001-2010. Based on the strategy criteria established in (Wang 2007) and (Werbin 2010), seven variables were selected. In agreement with bank theory, four “natural” clusters were obtained, named “Personal”, “Commercial”, “Typical” and “Other banks”. In order to understand this grouping, projection pursuit based robust principal component analysis was conducted on the whole set showing that essentially three variables can be attributed the formation of different clusters. In order to reveal each group inner structure, we used R package mclust to fit a finite Gaussian mixture to the data. This revealed approximately a similar component structure, granting a common principal components analysis as in (Boente and Rodrigues, 2002). This allowed us to identify three variables which suffice for grouping and characterizing each cluster. Boente’s influence measures were used to detect extreme cases in the common principal components analysis.El propósito de este documento es clasificar y caracterizar 64 bancos, activos en 2010 en la Argentina, mediante técnicas robustas utilizadas con información para el período 2001-2010. En base a los criterios de estrategia establecidos en (Wang 2007) y (Werbin 2010), se seleccionaron siete variables. De acuerdo con la teoría bancaria, se obtuvieron cuatro conglomerados "naturales", denominados "Personal", "Comercial", "Típico" y "Otros bancos". Para comprender este agrupamiento, se utilizó el todo el conjunto de banco y se realizó un análisis de los componentes principales basado en la proyección, que mostró que esencialmente tres variables pueden atribuirse a la formación de diferentes agrupaciones. A fin de revelar la estructura interna de cada grupo, utilizamos el paquete R mclust para ajustar una mezcla gaussiana finita a los datos. Esto reveló aproximadamente una estructura de componentes similar, lo que garantiza un análisis de componentes principales comunes como en (Boente y Rodrigues, 2002). Esto nos permitió identificar tres variables que son suficientes para agrupar y caracterizar cada cluster. Las medidas de influencia de Boente se utilizaron para detectar casos extremos en el análisis de componentes principales comunes

A jade pished hand-axe from Tubino's Cection (Valencina de la Concepción Local Museum, Sevilla, Spain)

A pished axe donated to the Valencina de la Concepción Museum (Seville, Spain) in November 2010, and that had belonged to Francisco María Tubino y Oliva's (1833-1888) personal clection, is studied. Although the exact provenance of this object is unknown, there are reasons to think that it might have been found on some archaẽogical site of the Seville province. Through the application of two different analytical techniques (XRD, DCμRS), this axe is identified as a jade-jadeite of purity above 95 ml%, which necessarily implies it came from the Alps. In the conclusions a discussion of this artifact is made in terms of long distance contact in Iberian Late Prehistory.Peer Reviewe

The massive stellar content in NGC604 and its evolutionary state

The ultraviolet resonance wind stellar lines, the nebular optical emission lines and the higher order terms of the Balmer series and HeI absorption lines detected in the spectra of NGC 604 are interpreted using evolutionary models optimized for young star forming regions. The evolutionary state and the massive stellar content of the region is derived in a self-consistent way. The three techniques applied suggest that the central ionizing cluster in NGC 604 is very young, 3 Myr old, and that the stars in the cluster were formed in an instantaneous burst following a Salpeter or flatter IMF, having stars more massive that 80 Msol. The stellar cluster is able to provide most of the ionizing photons needed to photoionize the whole nebula, and the wind power to form the central shell structure where the cluster core is located. The stellar cluster is affected by an extinction similar to the average extinction that affects the ionized gas. The estimated number of massive stars in the cluster is also in agreement with that derived from previous studies based on the detection of individual stars. The results that we present here support the use of these techniques for the interpretation of the integrated light of more distant star forming regionsComment: To be published in MNRAS. 17 pages and 17 figure

Factorizing the time evolution operator

There is a widespread belief in the quantum physical community, and in textbooks used to teach Quantum Mechanics, that it is a difficult task to apply the time evolution operator Exp{-itH/h} on an initial wave function. That is to say, because the hamiltonian operator generally is the sum of two operators, then it is a difficult task to apply the time evolution operator on an initial wave function f(x,0), for it implies to apply terms operators like (a+b)^n. A possible solution of this problem is to factorize the time evolution operator and then apply successively the individual exponential operator on the initial wave function. However, the exponential operator does not directly factorize, i. e. Exp{a+b} is not equal to Exp{a}Exp{b}. In this work we present a useful procedure for factorizing the time evolution operator when the argument of the exponential is a sum of two operators, which obey specific commutation relations. Then, we apply the exponential operator as an evolution operator for the case of elementary unidimensional potentials, like the particle subject to a constant force and the harmonic oscillator. Also, we argue about an apparent paradox concerning the time evolution operator and non-spreading wave packets addressed previously in the literature.Comment: 24 pages; added references; one figure change

Filling in the gaps in biowaste biorefineries : The use of the solid residue after enzymatic hydrolysis for the production of biopesticides through solid-state fermentation

Altres ajuts: acords transformatius de la UABAlternative production processes using waste are necessary to preserve non-renewable resources and prevent scarcity of materials for future generations. Biowaste, the organic fraction of municipal solid waste, is abundant and easily available. It can be fractionated into building blocks for which fermentative processes can be designed. By using solid-state fermentation, this paper proposes a method of valorizing biowaste's residual solid fraction after enzymatic hydrolysis. In a 22 L bioreactor, two digestates from anaerobic digestion processes were evaluated as cosubstrates to modify the acidic pH of the solid residue after enzymatic hydrolysis and promote the growth of the bacterial biopesticide producer Bacillus thuringiensis. Regardless of the cosubstrate used, the final microbial populations were similar indicating microbial specialization. The final product contained 4 × 10 spores per gram of dry matter and also crystal proteins of Bacillus thuringiensis var israelensis, which have insecticidal activity against pests. This method allows for the sustainable use of all materials liberated during the enzymatic hydrolysis of biowaste, including residual solids