FILOU oscillation code

The present paper provides a description of the oscillation code FILOU, its main features, type of applications it can be used for, and some representative solutions. The code is actively involved in CoRoT/ESTA exercises (this volume) for the preparation for the proper interpretation of space data from the CoRoT mission. Although CoRoT/ESTA exercises have been limited to the oscillations computations for non-rotating models, the main characteristic of FILOU is, however, the computation of radial and non-radial oscillation frequencies in presence of rotation. In particular, FILOU calculates (in a perturbative approach) adiabatic oscillation frequencies corrected for the effects of rotation (up to the second order in the rotation rate) including near degeneracy effects. Furthermore, FILOU works with either a uniform rotation or a radial differential rotation profile (shellular rotation), feature which makes the code singular in the field.Comment: 6 pages, 5 figures. Astrophysics and Space Science (in press

BoostNet: Bootstrapping detection of socialbots, and a case study from Guatemala

We present a method to reconstruct networks of socialbots given minimal input. Then we use Kernel Density Estimates of Botometer scores from 47,000 social networking accounts to find clusters of automated accounts, discovering over 5,000 socialbots. This statistical and data driven approach allows for inference of thresholds for socialbot detection, as illustrated in a case study we present from Guatemala.Comment: 7 pages, 4 figure

Gliridae (Rodentia, Mammalia) del Mioceno inferior de la fisura kárstica Rinascita 1 (Gargano, prov. Foggia, Italy).

Two new species of the endemic genus Stertomys (Mammalia, Rodentia, Gliridae) are described from the Late Miocene fissure filling Rinascita 1 on the palaeo-island Gargano (prov. Foggia, Italy): S. simplex and S. lyrifer. A third species is classified as S. aff. daamsi Freudenthal & Martín-Suárez, 2006. The fauna contains poor remains of three more species of Stertomys, and a non-endemic glirid: Dryomys apulus Freudenthal & Martín-Suárez, 2006. Two groups of species are recognized within the genus Stertomys: 1) Large species with complicated dental pattern: S. laticrestatus Daams & Freudenthal, 1985, S. daunius Freudenthal & Martín-Suárez, 2006, and S. lyrifer sp. nov. 2) Smaller species with a simpler dental pattern: S. daamsi Freudenthal & Martín-Suárez, 2006, S. simplex sp. nov., and S. aff. daamsi. Key words: Gliridae, Miocene, Italy, endemism, insularity.Se describen dos especies nuevas del género endémico Stertomys (Mammalia, Rodentia, Gliridae) de la fisura kárstica Rinascita 1 en la paleo-isla de Gargano (prov. Foggia, Italia): S. simplex y S. lyrifer. Una tercera especie se clasifica como S. aff. daamsi Freudenthal & Martín-Suárez, 2006. La fauna contiene tres especies de Stertomys más, que están representadas por muy poco material. Hay además un glirido no endémico: Dryomys apulus Freudenthal & Martín-Suárez, 2006. Se reconocen dos grupos de especies en el género Stertomys: 1) Especies grandes con dentición complicada: S. laticrestatus Daams & Freudenthal, 1985, S. daunius Freudenthal & Martín-Suárez, 2006, y S. lyrifer sp. nov. 2) Especies más pequeñas con dentición más sencilla: S. daamsi Freudenthal & Martín-Suárez, 2006, S. simplex sp. nov., y S. aff. daamsi. Palabras clave: Gliridae, Mioceno, Italia, endemismo, insularidad

VISIR-VLT high resolution study of the extended emission of four obscured post-AGB candidates

The onset of the asymmetry of planetary nebulae (PNe) is expected to occur during the late Asymptotic Giant Branch (AGB) and early post-AGB phases of low- and intermediate-mass stars. Among all post-AGB objects, the most heavily obscured ones might have escaped the selection criteria of previous studies detecting extreme axysimmetric structures in young PNe. Since the most heavily obscured post-AGB sources can be expected to descend from the most massive PN progenitors, these should exhibit clear asymmetric morphologies. We have obtained VISIR-VLT mid-IR images of four heavily obscured post-AGB objects barely resolved in previous Spitzer IRAC observations to analyze their morphology and physical conditions across the mid-IR. The VISIR-VLT images have been deconvolved, flux calibrated, and used to construct RGB composite pictures as well as color and optical depth maps that allow us to study the morphology and physical properties of the extended emission of these sources. We have detected extended emission from the four objects in our sample and resolved it into several structural components that are greatly enhanced in the temperature and optical depth maps. They reveal the presence of asymmetry in three young PNe (IRAS 15534-5422, IRAS 17009-4154, and IRAS 18454+0001), where the asymmetries can be associated with dusty torii and slightly bipolar outflows. The fourth source (IRAS 18229-1127), a possible post-AGB star, is better described as a rhomboidal detached shell. The heavily obscured sources in our sample do not show extreme axisymmetric morphologies. This is at odds with the expectation of highly asymmetrical morphologies in post-AGB sources descending from massive PN progenitors. The sources presented in this paper may be sampling critical early phases in the evolution of massive PN progenitors, before extreme asymmetries develop.Comment: 9 pages, 4 figure

Detailed study of SNR G306.3-0.9 using XMM-Newton and Chandra observations

We used combined data from XMM-Newton and Chandra observatories to study the X-ray morphology of SNR G306.3-0.9. A spatially-resolved spectral analysis was used to obtain physical and geometrical parameters of different regions of the remnant. Spitzer infrared observations were also used to constrain the progenitor supernova and study the environment in which the SNR evolved. The X-ray morphology of the remnant displays a non-uniform structure of semi-circular appearance, with a bright southwest region and very weak or almost negligible X-ray emission in its northern part. These results indicate that the remnant is propagating in a non-uniform environment as the shock fronts are encountering a high-density medium, where enhanced infrared emission is detected. The X-ray spectral analysis of the selected regions shows distinct emission-line features of several metal elements, confirming the thermal origin of the emission. The X-ray spectra are well represented by a combination of two absorbed thermal plasma models: one in equilibrium ionization with a mean temperature of ~0.19 keV, and another out of equilibrium ionization at a higher temperature of ~1.1 or 1.6-1.9 keV. For regions located in the northeast, central, and southwest part of the SNR, we found elevated abundances of Si, S, Ar, Ca, and Fe, typical of ejecta material. The outer regions located northwest and south show values of the abundances above solar but lower than to those found in the central regions. This suggests that the composition of the emitting outer parts of the SNR is a combination of ejecta and shocked material of the interstellar medium. The comparison between the S/Si, Ar/Si, and Ca/Si abundances ratios (1.75, 1.27, and 2.72 in the central region, respectively), favor a Type Ia progenitor for this SNR, a result that is also supported by an independent morphological analysis using X-ray and IR data.Comment: 8 pages, 7 figures. Accepted by Astronomy and Astrophysic

Avances en la obtención de tableros de fibras a partir de mezclas de residuales lignocelulósicos de bagazo

El pretratamiento del bagazo resulta fundamental en el fraccionamiento de la biomasa en sus componentes principales: celulosa, hemicelulosa y lignina, en la reducción de la cristalinidad de la celulosa y en el aumento del área superficial accesible. El trabajo tiene como objetivo la obtención preliminar de tableros de fibras a partir de la utilización de mezclas de bagazo con residuales lignocelulósicos obtenidos en las etapas de pretratamiento del bagazo (hidrólisis ácida y enzimática). Se realiza un diseño de experimento de mezclas, enrejado simplex de Scheffe utilizando una prensa de calentamiento. Se caracterizan los residuales celulósicos utilizando la técnica analítica Pulsy se evalúa la resistencia a la flexión de los tableros de fibras obtenidos. Los resultados favorecen a la utilización de mezclas de bagazo y sólido de la hidrólisis enzimática para la obtención de los tableros. Como conclusión, se propone continuar con el estudio de mezclas con adición de aglutinante y/o resina de manera que favorezcan las propiedades mecánicas de los tableros.