X-ray spectral variability of Seyfert 2 galaxies

Variability across the electromagnetic spectrum is a property of AGN that can help constraining the physical properties of these galaxies. This is the third of a serie of papers with the aim of studying the X-ray variability of different families of AGN. The main purpose of this work is to investigate the variability pattern in a sample of optically selected type 2 Seyfert galaxies. We use the 26 Seyferts in the Veron-Cetty and Veron catalogue with data available from Chandra and/or XMM-Newton public archives at different epochs, with timescales ranging from a few hours to years. All the spectra of the same source are simultaneously fitted and we let different parameters to vary in the model. Whenever possible, short-term variations and/or long-term UV flux variations are studied. We divide the sample in Compton-thick, Compton-thin, and changing-look candidates. Short-term variability at X-rays is not found. From the 25 analyzed sources, 11 show long-term variations; eight (out of 11) are Compton-thin, one (out of 12) is Compton-thick, and the two changing-look candidates are also variable. The main driver for the X-ray changes is related to the nuclear power (nine cases), while variations at soft energies or related with absorbers at hard X-rays are less common, and in many cases these variations are accompained with variations of the nuclear continuum. At UV frequencies nuclear variations are nor found. We report for the first time two changing-look candidates, MARK273 and NGC7319. A constant reflection component located far away from the nucleus plus a variable nuclear continuum are able to explain most of our results; the Compton-thick candidates are dominated by reflection, which supresses their continuum making them seem fainter, and not showing variations, while the Compton-thin and changing-look candidates show variations.Comment: Accepted for publication in A&

X-ray spectral variability of seven LINER nuclei with XMM-Newton and Chandra data

One of the most important features in active galactic nuclei (AGN) is the variability of their emission. Variability has been discovered at X-ray, UV, and radio frequencies on time scales from hours to years. Among the AGN family and according to theoretical studies, Low-Ionization Nuclear Emission Line Region (LINER) nuclei would be variable objects on long time scales. Our purpose is to investigate spectral X-ray variability in LINERs and to understand the nature of these kinds of objects, as well as their accretion mechanism. Chandra and XMM-Newton public archives were used to compile X-ray spectra of seven LINER nuclei at different epochs with time scales of years. To search for variability we fit all the spectra from the same object with a set of models, in order to identify the parameters responsible for the variability pattern. We also analyzed the light curves in order to search for short time scale (from hours to days) variability. Whenever possible, UV variability was also studied. We found spectral variability in four objects, with variations mostly related to hard energies (2-10 keV). These variations are due to changes in the soft excess, and/or changes in the absorber, and/or intrinsic variations of the source. Another two galaxies seem not to vary. Short time scale variations during individual observations were not found. Our analysis confirms the previously reported anticorrelation between the X-ray spectral index and the Eddington ratio, and also the correlation between the X-ray to UV flux ratio and the Eddington ratio. These results support an Advection Dominated Accretion Flow (ADAF) as the accretion mechanism in LINERs.Comment: 35 pages, 53 figures, recently accepted pape

X-ray spectral variability of LINERs selected from the Palomar sample

Variability is a general property of active galactic nuclei (AGN). At X-rays, the way in which these changes occur is not yet clear. In the particular case of low ionisation nuclear emission line region (LINER) nuclei, variations on months/years timescales have been found for some objects, but the main driver of these changes is still an open question. The main purpose of this work is to investigate the X-ray variability in LINERs, including the main driver of such variations, and to search for eventual differences between type 1 and 2 objects. We use the 18 LINERs in the Palomar sample with data retrieved from Chandra and/or XMM-Newton archives corresponding to observations gathered at different epochs. All the spectra for the same object are simultaneously fitted in order to study long term variations. The nature of the variability patterns are studied allowing different parameters to vary during the spectral fit. Whenever possible, short term variations from the analysis of the light curves and UV variability are studied.Comment: 49 pages, accepted. arXiv admin note: text overlap with arXiv:1305.222

University experience on the functions of social educator with 2.0 technologies

En el artículo se describe una experiencia de innovación en enseñanza universitaria, con presentaciones educativas interactivas sobre las principales funciones del Educador/a Social. Entre sus objetivos destacan: Reflexionar sobre las principales funciones del profesional de la Educación Social, favorecer el rol activo y autónomo de los estudiantes en el proceso de construcción del conocimiento. La experiencia educativa ha corroborado que las principales funciones reconocidas para este alumnado son orientar (66,15%), educar y enseñar conocimientos y experiencias (52,31%), motivar (41,54%), dinamizar (40%), informar y promover (27,69%), tutorizar (24,62%), evaluar (18,46%), investigar (16,92%), intervenir socialmente y favorecer los procesos de mediación (13,85%).The article describes an innovative experience in university teaching, with interactive educational presentations on key functions of Social Educator. Its objectives include: Reflect on the main professional functions of social education, promote active and independent role of students in the process of building knowledge, promote learning. The study confirmed that the main functions for students are: guide (66.15%), educate, and teach or transfer knowledge and experience (52.31%), motivate (41.54%), animate and stimulate (40%), inform and promote (27.69%), facilitate processes and tutoring (24.62%), evaluate (18.46%), investigate (16.92%), be socially involved and encourage mediation processes (13,85%)

Experiencias universitarias en diferentes titulaciones de la universidad Pablo de Olavide : construcción de ideas previas sobre la sociedad de la información con software social 2.0

La investigación describe una experiencia innovadora universitaria con software social a través de nubes de palabras (Word Clouds) sobre las características principales de la Sociedad de la Información correspondientes a dos titulaciones de Grado y Doble Grado de Educación Social y Trabajo Social de la Facultad de Ciencias Sociales de la Universidad Pablo de Olavide (Sevilla), correspondiente al curso académico 2011-12. Su enlace es: http://practicas3000.jimdo.com/. El presente estudio forma parte de la investigación denominada: "Formación didáctica en Cloud Computing: Competencias digitales, estrategias didácticas y e-actividades con tecnología Web 2.0 en el EEES", en el marco de la Acción 2 de Proyectos de Innovación y Desarrollo Docente subvencionado por el Vicerrectorado de Docencia y Convergencia Europea de la mencionada Universidad. Entre los objetivos destacan: fomentar el papel activo y autónomo de los estudiantes en el proceso de construcción del conocimiento, indagar sobre las ideas previas del alumnado sobre la Sociedad de la Información, elaborar on-line nubes de conceptos/ palabras (Word Clouds ) con aplicaciones relacionadas con el software social, crear un repositorio sobre esta temática para posteriores promociones académicas y reflexionar sobre las concepciones previas en relación con la Sociedad de la Información actual.This research describes an experience of university innovative with social software through Word Clouds about the principal features of the Information Society for two degrees (Graduate in Social Education and Graduate Double at Social Education and Social Work) of the Faculty of Social Sciencies of the University Pablo de Olavide (Seville), for academic course 2011-12. This is the link: http://practicas3000.jimdo.com/. The present study is part of the research called: "Didactic formation in Cloud Computing: Digital competences, didactics strategies y e-task with Web 2.0 tecnology in EEES", under Action 2 of Innotation Projects and Faculty Development subsidized by Vice President for Teaching and European Convergence of mentioned University. Between the objetives stand: promote the active and autonomous paper of students in construction of knowledge process, investigate about previous ideas of the student body about the Information Society, develop on-line Word Clouds with applications related with the social software, create a repository about this topic for subsequent academic promotions and reflect on preconceptions regarding the current Information Society

Sphaerosporella brunnea (Alb. et Schwein.) Svrcek et Kubicka, un discomicete con incidencia en la truficultura e interés forestal

Sphaerosporella brunnea (Alb. et Schwein.) Svrcek et Kubicka, a cup-shaped ascomycete related with truffle cultures and afforestation. A casual finding of Sphaerosporella brunnea in some greenhouses from Spain, growing in connection with several ectomycorrhizal plants, is reported. These plants were experimentally inoculated with low level inoculum of Tuber melanosporum. Sphaerosporella brunnea is described and illustrated, and its negative role in truffle cultures and its possible utilization in burned are as recovery is emphasized.Se da cuenta del hallazgo casual, en unos viveros españoles de Sphaerosporella brunnea, formando micorrizas con plantas diversas, las cuales habían sido inoculadas experimentalmente con niveles bajos de Tuber melanosporum. Se describe e ilustra esta especie, al tiempo que se destaca su papel negativo en la truficultura y su posible utilización en la recuperación de áreas incendiadas

Sphaerosporella brunnea (Alb. et Schwein.) Svrcek et Kubicka, un discomicete con incidencia en la truficultura e interés forestal

Se da cuenta del hallazgo casual, en unos viveros españoles de Sphaerosporella brunnea, formando micorrizas con plantas diversas, las cuales habían sido inoculadas experimentalmente con niveles bajos de Tuber melanosporum. Se describe e ilustra esta especie, al tiempo que se destaca su papel negativo en la truficultura y su posible utilización en la recuperación de áreas incendiadas.Sphaerosporella brunnea (Alb. et Schwein.) Svrcek et Kubicka, a cup-shaped ascomycete related with truffle cultures and afforestation. A casual finding of Sphaerosporella brunnea in some greenhouses from Spain, growing in connection with several ectomycorrhizal plants, is reported. These plants were experimentally inoculated with low level inoculum of Tuber melanosporum. Sphaerosporella brunnea is described and illustrated, and its negative role in truffle cultures and its possible utilization in burned are as recovery is emphasized

Detenninación de humedad en cereales y derivados por calentamiento con microondas y análisis de hidroximetilfurfural (HMF) formado

EL horno microondas ha sido usado para evaluar el tiempo y preclslOn en la determinación de humedad de granos de trigo y arroz, harina de trigo, pan blanco y galletas. Los resultados fueron comparados con el metodo estandard de estufa de aire. El tiempo para las muestras de granos de trigo y arroz fue de 40 y 60 minutos respectivamente y de 15 minutos para el resto de los productos. Sin embargo, la precisión obtenida para todas las muestras, fue menor que con estufa de aire. Se determinó HMF en muestras de harina desecadas por ambos métodos y los resultados mostraron valores considerablemente más elevados en la desecación mediante microondas.A study was conducted to evaluate the use and accuracy of domestic microwave oven for quick moisture determination of wheat and rice grains, wheat flour, sliced white bread and biscuits. The results were compared with the standard air-oven method. A decrease in drying time was achieved using the microwave oven. For wheat and rice grains the drying times were 40 and 60 min repectively, and 15 min for the cereal products, although coefficients of variation were lower in the air oven. Hydroxyrnethylfurfural (HMF) was deterrnined in flour samples dried by both methods. The results were considerately higher by microwave oven