La intervención del trabajo social en emergencias

Esta investigación ha pretendido conocer cómo se interviene en grandes emergencias o catástrofes desde la profesión del trabajo social con el fin de comprender si es necesaria una intervención en estas situaciones críticas desde esta profesión

SPITZER: Accretion in Low Mass Stars and Brown Dwarfs in the Lambda Orionis Cluster

We present multi-wavelength optical and infrared photometry of 170 previously known low mass stars and brown dwarfs of the 5 Myr Collinder 69 cluster (Lambda Orionis). The new photometry supports cluster membership for most of them, with less than 15% of the previous candidates identified as probable non-members. The near infrared photometry allows us to identify stars with IR excesses, and we find that the Class II population is very large, around 25% for stars (in the spectral range M0 - M6.5) and 40% for brown dwarfs, down to 0.04 Msun, despite the fact that the H(alpha) equivalent width is low for a significant fraction of them. In addition, there are a number of substellar objects, classified as Class III, that have optically thin disks. The Class II members are distributed in an inhomogeneous way, lying preferentially in a filament running toward the south-east. The IR excesses for the Collinder 69 members range from pure Class II (flat or nearly flat spectra longward of 1 micron), to transition disks with no near-IR excess but excesses beginning within the IRAC wavelength range, to two stars with excess only detected at 24 micron. Collinder 69 thus appears to be at an age where it provides a natural laboratory for the study of primordial disks and their dissipation.Comment: ApJ, in pres

Extracellular vesicles from induced neurons trigger epigenetic silencing of a brain neurotransmitter.

Introduction: Antithrombin (AT) is a glycoprotein involved in the regulation of blood coagulation. It belongs to the family of serine-protease inhibitors and acts as the most important antagonist of different clot- ting factors. Two types of inherited AT deficiency can be distinguished: Type I (quantitative deficit), and Type II (qualitative deficit). The latter is characterized by an impaired inhibitory activity related to dysfunc- tional domains of the protein. Three Type II subtypes can be defined: Type IIa (reactive site defect), Type IIb (heparin binding site defect) and Type IIc (pleiotropic defect). This classification has clinical importance since these subtypes have a different thrombotic risk. No functional routine diagnostic assay, however, can be assumed to detect all forms of Type II deficiencies since false-negative results may hamper the diagnosis. Methods: We analysed the biochemical/biophysical association of ATT to EVs. We separated EVs from plasma of healthy or Type II affected patients or from cultured hepatocytes through differential ultracentrifu- gation followed by sucrose density gradient and/or immunoprecipitation. We next combined dot blot ana- lysis, WB, 2D electrophoresis and enzymatic assays to reveal the nature of ATT association to EVs. Results: We evidenced that ATT is associated to the external leaflet of EVs. We also found that specific ATT isoforms are enriched in EV preparations in respect to total plasma and that those isoforms are selectively associated to EVs when comparing healthy or ATT type II deficient patients. Summary/Conclusion: ATT selective association pat- tern to EVs might be related either to mutations in the primary sequence of the protein or alterations in the glycosylation process, hence experiments are ongoing to reveal the nature of this phenomenon. Our findings suggest that analysis of ATT enriched in EV prepara- tions might be useful to gain insights into the patho- genesis and be of support in the diagnostic algorithm of ATT deficiency. Funding: This work acknowledges FFABR (Fondo finanziamento attività Base di ricerca from MIUR, Ministry of Education, Universities and Research, Italy) for financial support

Formamidinium halide salts as precursors of carbon nitrides

13 figures, 6 tables.-- Supplementary information available.Pyrolysis of formamidinium halide salts (FAI, FABr) results in a new type of amorphous carbon nitride materials with a mass fraction of 40–50% nitrogen content. Pyrolysis temperature drives final chemical composition, morphology, optical and electrical properties of the material independently of the halide precursor and identifying triazine ring, instead of typical heptazine unit, as the main building block of this material. We elaborated a temperature dependent mechanism of formation for these materials and foresee its potential value as native passivation layer in the field of perovskite solar cells.E.J.J-P acknowledges the funding support from MCIN/AEI/10.13039/501100011033 and European Union NextGenerationEU/PRTR (project grants PID2019-107893RB-I00 and EIN2020-112315, respectively). M.H. acknowledges the funding support from MCIN/AEI/10.13039/501100011033 for the Ramón y Cajal fellowship (RYC-2018-025222-I) and the project PID2019-108247RA-I00. R.A. acknowledges funding from the Spanish MICINN (project grant PID2019-104739 GB-100/AEI/10.13039/501100011033). RA also acknowledge to Government of Aragon (project DGA E13-20R (FEDER, EU)) and European Union H2020 program “ESTEEM3” (823717). A.A-C acknowledges financial support from Spanish MCIN/AEI/10.13039/501100011033 under project PID2019-104272RB-C51/AEI/10.13039/501100011033 and the Diputación General de Aragón under project T03_20R (Grupo Reconocido).Peer reviewe

A large-scale optical-near infrared survey for brown dwarfs and very low-mass stars in the Orion OB1 association

We report the initial results of a large-scale optical-near infrared survey to extend the known young population of the entire Orion star-forming region down to the substellar domain. Using deep optical I-band photometry and data from the 2MASS survey, we selected candidates across ~14.8 deg^2 in the ~8 Myr old Ori OB1a subassociation and over ~6.7 deg^2 in the Ori OB1b subassociation (age ~3), with completeness down to 0.05Mo and 0.072Mo respectively. We obtained low resolution optical spectra for a subsample of 4 candidates in Ori OB1a and 26 in Ori OB1b; as a result we confirmed 3 new members in Ori OB1a, one of which is substellar, and 19 new members in Ori OB1b, out of which 7 are at the substellar limit and 5 are substellar. We looked into the presence of accretion signatures by measuring the strength of the Ha line in emission. Accordingly, we classified the new members as having Classical T-Tauri star (CTTS) or Weak Lined T Tauri star-like (WTTS) nature. We found that all the new members confirmed in Ori OB1a are WTTSs, while 39 +25/-22 % of the new members in Ori OB1b exhibit CTTS-like behavior, suggestive of ongoing accretion from a circum(sub)stellar disk. Additionally we found that none of the members confirmed in OB1a show near-IR color excess while 38 +26/-21 % of OB1b members show H-K color excess. These results are consistent with recent findings for low mass young stars in Orion OB1. The similarity in CTTS-like properties and near-IR excess across the substellar boundary gives support to the idea of a common formation mechanism for low mass stars and at least the most massive brown dwarfs. Finally, we remark the discovery of two new members classified as CTTSs, both exhibiting W(Ha) < -140 A, suggesting significant ongoing accretion.Comment: Accepted for publication in Astronomical Journa

Spitzer Observations of the Lambda Orionis cluster. II. Disks around solar-type and low mass stars

We present IRAC/MIPS Spitzer Space Telescope observations of the solar type and the low mass stellar population of the young (~5 Myr) Lambda Orionis cluster. Combining optical and 2MASS photometry, we identify 436 stars as probable members of the cluster. Given the distance (450 pc) and the age of the cluster, our sample ranges in mass from 2 solar mass to objects below the substellar limit. With the addition of the Spitzer mid-infrared data, we have identified 49 stars bearing disks in the stellar cluster. Using spectral energy distribution (SED) slopes, we place objects in several classes: non-excess stars (diskless), stars with optically thick disks, stars with ``evolved disks''( with smaller excesses than optically thick disk systems), and ``transitional disks'' candidates (in which the inner disk is partially or fully cleared). The disk fraction depends on the stellar mass, ranging from ~6% for K type stars (Rc-J<2) to ~27% for stars with spectral type M5 or later (Rc-J>4). We confirm the dependence of disk fraction on stellar mass in this age range found in other studies. Regarding clustering levels, the overall fraction of disks in the Lambda Orionis cluster is similar to those reported in other stellar groups with ages normally quoted as ~5 Myr.Comment: 37 pages, 11 Figures and 3 Tables, Accepted for publication in The Astrophysical Journa

KOBEsim: A Bayesian observing strategy algorithm for planet detection in radial velocity blind-search surveys

Context. Ground-based observing time is precious in the era of exoplanet follow-up and characterization, especially in high-precision radial velocity instruments. Blind-search radial velocity surveys thus require a dedicated observational strategy in order to optimize the observing time, which is particularly crucial for the detection of small rocky worlds at large orbital periods. Aims. We developed an algorithm with the purpose of improving the efficiency of radial velocity observations in the context of exoplanet searches, and we applied it to the K-dwarfs Orbited By habitable Exoplanets experiment. Our aim is to accelerate exoplanet confirmations or, alternatively, reject false signals as early as possible in order to save telescope time and increase the efficiency of both blind-search surveys and follow-up of transiting candidates. Methods. Once a minimum initial number of radial velocity datapoints is reached in such a way that a periodicity starts to emerge according to generalized Lomb-Scargle periodograms, that period is targeted with the proposed algorithm, named KOBEsim. The algorithm selects the next observing date that maximizes the Bayesian evidence for this periodicity in comparison with a model with no Keplerian orbits. Results. By means of simulated data, we proved that the algorithm accelerates the exoplanet detection, needing 29-33% fewer observations and a 41-47% smaller time span of the full dataset for low-mass planets (mp < 10 M⊕) in comparison with a conventional monotonic cadence strategy. For 20 M⊕ planets we found a 16% enhancement in the number of datapoints. We also tested KOBEsim with real data for a particular KOBE target and for the confirmed planet HD 102365 b. These two tests demonstrate that the strategy is capable of speeding up the detection by up to a factor of 2 (i.e., reducing both the time span and number of observations by half).14 página

Project goals, target selection, and stellar characterization

The detection of habitable worlds is one of humanitya-s greatest endeavors. Thus far, astrobiological studies have shown that one of the most critical components for allowing life to develop is liquid water. Its chemical properties and its capacity to dissolve and, hence, transport other substances makes this constituent a key piece in this regard. As a consequence, looking for life as we know it is directly related to the search for liquid water. For a remote detection of life in distant planetary systems, this essentially means looking for planets in the so-called habitable zone. In this sense, K-dwarf stars are the perfect hosts to search for planets in this range of distances. Contrary to G-dwarfs, the habitable zone is closer, thus making planet detection easier using transit or radial velocity techniques. Contrary to M-dwarfs, stellar activity is on a much smaller scale, hence, it has a smaller impact in terms of both the detectability and the true habitability of the planet. Also, K-dwarfs are the quietest in terms of oscillations, and granulation noise. In spite of this, there is a dearth of planets in the habitable zone of K-dwarfs due to a lack of observing programs devoted to this parameter space. In response to a call for legacy programs of the Calar Alto observatory, we have initiated the first dedicated and systematic search for habitable planets around these stars: K-dwarfs Orbited By habitable Exoplanets (KOBE). This survey is monitoring the radial velocity of 50 carefully pre-selected K-dwarfs with the CARMENES instrument over five semesters, with an average of 90 data points per target. Based on planet occurrence rates convolved with our detectability limits, we expect to find 1.68 ± 0.25 planets per star in the KOBE sample. Furthermore, in half of the sample, we expect to find one of those planets within the habitable zone. Here, we describe the motivations, goals, and target selection for the project as well as the preliminary stellar characterization. © 2022 EDP Sciences. All rights reserved

Development of polymer-based nanocomposite films with electrical properties based on silver nanowires

This project has been focus on the synthesis of silver nanowires by a chemical process to be used in the preparation of nanocomposites with electrical properties. Polycarbonate has been used as matrix and the nanocomposite films were prepared by the casting method. The main objective is to achieve electrical properties in polycarbonate by the addition of silver nanowires. This project collects a comprehensive study about silver nanowires synthesis by polyol method. The optimal condition to obtain and preserve the silver nanowires has been studied changing the different synthesis parameters and the storage methods. Silver nanowires were characterized using different techniques (SEM, TEM, UV-Vis and XRD) obtaining information about their size and morphology. The synthesized silver nanowires were embedded in a polycarbonate matrix obtaining thin films with a good dispersion of the silver nanowires inside the polymeric matrix using casting method. A deep study has been carried out in order to obtain the better conditions to obtain the nanocomposite films. The project includes the characterization of this nanocomposite films by several techniques (SEM, TGA and optical microscopy). The electrical behaviour of polycarbonate / silver nanowires nanocomposite films has been studied, analysing the complex impedance of these. High conductivity has been achieved for these nanocomposite films

Preparación y caracterización de materiales zeolíticos de poro y propiedades de adsorción ajustables

En esta tesis se han sintetizado materiales de diferentes tamaños de poro: materiales microporosos con estructura tipo umbita; un material mesoporoso, como son las esferas de sílice; y un material con estructura de poro jerarquizada, como son las esferas huecas de silicalita. Estas esferas están formadas por un sistema de microporos/mesoporos/macroporos. El estudio de estos materiales se ha dividido en dos secciones: 1. SÍNTESIS DE MATERIALES ISOMORFOS DE LA ESTRUCTURA TIPO UMBITA Y SU INTERCAMBIO IÓNICO La umbita es un mineral circonosilicato cuya formula ideal es K2ZrSi3O9.H2O. En este trabajo se han sintetizado tres materiales isomorfos de este mineral: K2TiSi3O9.H2O, K2ZrSi3O9.H2O y K2SnSi3O9.H2O. A partir de estos materiales se ha realizado el intercambio iónico del K(I) por Cu(II) o Sr(II), formando: KxCuyZrSi3O9.zH2O, KxSryZrSi3O9.zH2O KxCuySnSi3O9.zH2O, KxSrySnSi3O9.zH2O, KxCuyTiSi3O9.zH2O, KxSrySi3O9.zH2O. Todos los materiales han sido caracterizados por XRD y TGA. Además, las muestras isomorfas se han caracterizado por SEM y adsorción de NH3, mientras que las umbitas intercambiadas lo han sido por ICP. También, se ha determinado la estructura de los materiales isomorfos con el objetivo de conocer el efecto que tiene el sustituir un catión de Zr por otro de Ti o Sn en el tamaño de poro; y el volumen de celda de los materiales intercambiados. De esta manera, se ha relacionado la estructura con la capacidad de adsorción que presentan estos material. 2. SÍNTESIS Y CARACTERIZACIÓN DE ESFERAS DE SÍLICE Y ESFERAS HUECAS DE SILICALITA-1 Se ha optimizado el modo de formar esferas huecas de silicalita a partir de esferas de sílice. Para ello, se ha estudiado la influencia de numerosas variables (forma de llevar acabo la deposición de semillas de silicalita, composición del gel de síntesis, temperatura de síntesis, tiempo de síntesis....) en la aglomeración de las esferas, en el número de esferas incompletas o en el tamaño de los cristales de silicalita. Estas muestras han sido caracterizadas por XRD, SEM, ICP, RMN, TGA, adsorción N2, FTIR y TEM, no solo para conocer la influencia de las variables mencionadas anteriormente, sino también, para conocer el mecanismo de formación de las esferas huecas de silicalita. También se ha estudiado las propiedades de adsorción (TPB, hexano, agua...) de este material, comparándolo con el que presenta los cristales de silicalita, las esferas de sílice o las esferas de silicalita trituradas