Auto-consistent metallicity and star formation history of the nearest blue compact dwarf galaxy NGC 6789

We present a detailed auto-consistent study of the nearest blue compact dwarf galaxy NGC 6789 by means of optical and UV archive photometry data and optical long-slit ISIS-WHT spectroscopy observations of the five brightest star-forming knots. The analysis of the spectra in all knots allowed the derivation of ionic chemical abundances of oxygen, nitrogen, sulphur, argon and neon using measures of both the high- and low-excitation electron temperatures, leading to the conclusion that NGC 6789 is chemically homogeneous with low values of the abundance of oxygen in the range 12+log(O/H) = 7.80-7.93, but presenting at the same time higher values of the nitrogen-to-oxygen ratio than expected for its metal regime. We used archival HST/WFPC2 F555W and F814W observations of NGC 6789 to perform a photometric study of the colour-magnitude diagram (CMD) of the resolved stellar populations and derive its star formation history (SFH), which is compatible with the presence of different young and old stellar populations whose metallicities do not necessarily increase with age. We fit the observed optical spectrum in all the five knots using the STARLIGHT code and a combination of single stellar populations following the SFH obtained from the CMD. We compare the resulting stellar masses and the relative fractions of the ionising populations with a non-constrained SFH case. The properties of the younger populations were obtained using CLOUDY photoionisation models, giving similar ages in all the knots in the range 3-6 Myr and the estimation of the dust absorption factor, which correlates with the observed GALEX FUV-NUV colour indices. The total photometric extinction and dust-absorption corrected H\alpha\ fluxes were finally used to derive the star formation rates.Comment: 18 pages, 6 figures, 10 tables; accepted by MNRA

El desafío de la posmodernidad para el cristiano - The challenge of postmodernism for Christian

Vivir en una sociedad posmoderna, caracterizada por un discurso antirreligioso y por su relativismo moral, constituye en sí mismo un gran desafío para los cristianos, especialmente para el segmento más joven. Este artículo ofrece una descripción de algunas de las características de nuestra sociedad que nos permitirán conocerla mejor y comprender el enorme desafío que ella representa para quienes enarbolan los principios de la fe cristiana

Cloud-like Management of Grid Sites 2.0 Software

This document presents the features implemented for the automatic deployment and dynamic provision of grid services, and for the scalable cloud-like management of grid site resources in the second year of the project. These features, developed largely in Work Package 6 (WP6), are integrated into the StratusLab Toolkit by Work Package 4 (WP4)

Promoting sustainability in education through the implementation of green walls for greywater treatment

This study describes the methodology followed to design, build and operate a pilot green wall treating greywater from a vocational training center. The study was carried out in the framework of a master thesis in Environmental Engineering carried out in collaboration with the vocational training center where the pilot system was built. The system consisted of several pots arranged in rows planted with different species of macrophytes. Results showed a successful removal efficiency of the main pollutants (total solids and organic matter), while further post-treatment would be needed to reduce turbidity and pathogens in order to fulfill water reuse standards. This work shows how teaching in certain engineering studies can focus on sustainability and perform a practical work involving younger students from a vocational training center

Cloud-like Management of Grid Sites 1.0 Software

This document presents the features implemented for the automatic deployment and dynamic provision of grid services, and for the scalable cloud-like management of grid site resources. These features, developed largely in Work Package 6 (WP6) are integrated into the StratusLab Toolkit by Work Package 4 (WP4). They involve cloud-like APIs, a service definition language, contextualization, scalable cloud frameworks, monitoring and accounting solutions. Some functionalities developed include TCloud and OCCI implementations, a library to process OVF, the Claudia framework and integration with Ganglia monitoring information

UPM system for WMT 2012

This paper describes the UPM system for the Spanish-English translation task at the NAACL 2012 workshop on statistical machine translation. This system is based on Moses. We have used all available free corpora, cleaning and deleting some repetitions. In this paper, we also propose a technique for selecting the sentences for tuning the system. This technique is based on the similarity with the sentences to translate. With our approach, we improve the BLEU score from 28.37% to 28.57%. And as a result of the WMT12 challenge we have obtained a 31.80% BLEU with the 2012 test set. Finally, we explain different experiments that we have carried out after the competition

Perturbaciones relativas e integración de conceptos y estrategias

La resolución de problemas está comprometida no solamente con las pruebas deductivas, sino también con argumentaciones inductivas y generalizaciones a partir de la observación de casos. En este artículo describimos una experiencia interesada en desarrollar perspectivas innovadoras en la resolución de problemas, construyendo conexiones entre inducción y deducción. Un problema fundamental del cálculo numérico es la solución de sistemas de ecuaciones lineales Ax = b. En este estudio nueve parejas de estudiantes, de las clases de Cálculo Numérico, estuvieron comprometidos con el siguiente problema: si los datos en b son perturbados por la cantidad 8b, ¿cómo pueden explicarse las perturbaciones en la solución x

Influence of liquid-to-biogas ratio and alkalinity on the biogas upgrading performance in a demo scale algal-bacterial photobioreactor

The influence of the liquid-to-biogas ratio (L/G) and alkalinity on methane quality was evaluated in a 11.7 m3 outdoors horizontal semi-closed tubular photobioreactor interconnected to a 45-L absorption column (AC). CO2 concentrations in the upgraded methane ranged from <0.1 to 9.6% at L/G of 2.0 and 0.5, respectively, with maximum CH4 concentrations of 89.7% at a L/G of 1.0. Moreover, an enhanced CO2 removal (mediating a decrease in CO2 concentration from 9.6 to 1.2%) and therefore higher CH4 contents (increasing from 88.0 to 93.2%) were observed when increasing the alkalinity of the AC cultivation broth from 42 ± 1 mg L−1 to 996 ± 42 mg L−1. H2S was completely removed regardless of the L/G or the alkalinity in AC. The continuous operation of the photobioreactor with optimized operating parameters resulted in contents of CO2 (<0.1%–1.4%), H2S (<0.7 mg m−3) and CH4 (94.1%–98.8%) complying with international regulations for methane injection into natural gas grids.Peer ReviewedPostprint (published version

Implementation and Provisioning of Federated Networks in Hybrid Clouds (pre-print)

Federated cloud networking is needed to allow the seamless and efficient interconnection of resources distributed among different clouds. This work introduces a new cloud network federation framework for the automatic provision of Layer 2 (L2) and layer 3 (L3) virtual networks to interconnect geographically distributed cloud infrastructures in a hybrid cloud scenario. After a revision of existing encapsulation technologies to implement L2 and L3 overlay networks, the paper analyzes the main topologies that can be used to construct federated network overlays within hybrid clouds. In order to demonstrate the proposed solution and compare the different topologies, the article shows a proof-of-concept of a real federated network deployment in a hybrid cloud, which spans a local private cloud, managed with OpenNebula, and two public clouds, two different regions of mazon EC2. Results show that L2 and L3 overlay connectivity can be achieved with a minimal bandwidth overhead, lower than 10%