68 research outputs found

    IRAM-30m large scale survey of 12^{12}CO(2-1) and 13^{13}CO(2-1) emission in the Orion molecular cloud

    Full text link
    Using the IRAM 30m telescope we have surveyed a 1×0.81\times0.8^{\circ} part of the Orion molecular cloud in the 12^{12}CO and 13^{13}CO (2-1) lines with a maximal spatial resolution of \sim11" and spectral resolution of \sim 0.4 km~s1^{-1}. The cloud appears filamentary, clumpy and with a complex kinematical structure. We derive an estimated mass of the cloud of 7700 MSun_{\text{Sun}} (half of which is found in regions with visual extinctions AVA_V below \sim10) and a dynamical age for the nebula of the order of 0.2 Myrs. The energy balance suggests that magnetic fields play an important role in supporting the cloud, at large and small scales. According to our analysis, the turbulent kinetic energy in the molecular gas due to outflows is comparable to turbulent kinetic energy resulting from the interaction of the cloud with the HII region. This latter feedback appears negative, i.e. the triggering of star formation by the HII region is inefficient in Orion. The reduced data as well as additional products such as the column density map are made available online at http://userpages.irap.omp.eu/~oberne/Olivier_Berne/Data

    Discovery of five cyano derivatives of propene with the QUIJOTE line survey

    Full text link
    We report the discovery of five cyano derivatives of propene towards TMC-1 with the QUIJOTE line survey: transtrans and ciscis-crotononitrile (tt-CH3_3CHCHCN, cc-CH3_3CHCHCN), methacrylonitrile (CH2_2C(CH3_3)CN), and gauchegauche and ciscis-allyl cyanide (gg-CH2_2CHCH2_2CN and cc-CH2_2CHCH2_2CN). The observed transitions allowed us to derive a common rotational temperature of 7±\pm1 K for all them. The derived column densities are N(tt-CH3_3CHCHCN)=(5±\pm0.5)×\times1010^{10} cm2^{-2}, N(cc-CH3_3CHCHCN)=(1.3±\pm0.2)×\times1011^{11} cm2^{-2}, N(CH2_2C(CH3_3)CN)=(1.0±\pm0.1)×\times1011^{11} cm2^{-2}, N(gg-CH2_2CHCH2_2CN)=(8.0±\pm0.8)×\times1010^{10} cm2^{-2}, and N(cc-CH2_2CHCH2_2CN)=(7.0±\pm0.7)×\times1010^{10} cm2^{-2}, respectively. The abundance of cyano-propene relative to that of propene is thus \sim102^{-2}, which is considerably lower than those of other cyano derivatives of abundant hydrocarbons. Upper limits are obtained for two ethynyl derivatives of propene (EE and ZZ-CH3_3CHCHCCH).Comment: Accepted for publication in Astronomy and Astrophysics Letter

    Ionization fraction and the enhanced sulfur chemistry in Barnard 1

    Get PDF
    30 págs.; 14 figs.; 5 tabs.; 2 apps.Context. Barnard B1b has been revealed as one of the most interesting globules from the chemical and dynamical point of view. It presents a rich molecular chemistry characterized by large abundances of deuterated and complex molecules. Furthermore, this globule hosts an extremely young Class 0 object and one candidate for the first hydrostatic core (FHSC) proving the youth of this star-forming region. Aims. Our aim is to determine the cosmic ray ionization rate, ζH, and the depletion factors in this extremely young star-forming region. These parameters determine the dynamical evolution of the core. Methods. We carried out a spectral survey toward Barnard 1b as part of the IRAM large program >IRAM Chemical survey of sun-like star-forming regions> (ASAI) using the IRAM 30-m telescope at Pico Veleta (Spain). This provided a very complete inventory of neutral and ionic C-, N-, and S-bearing species with, from our knowledge, the first secure detections of the deuterated ions DCS and DOCO. We use a state-of-the-art pseudo-time-dependent gas-phase chemical model that includes the ortho and para forms of H, H, D, H, HD, DH, D, and D to determine the local value of the cosmic ray ionization rate and the depletion factors. Results. Our model assumes n(H) = 10 cm and T = 12 K, as derived from our previous works. The observational data are well fitted with ζH between 3 × 10 s and 10 s and the elemental abundances O/H = 3 × 10, N/H = 6.4-8 × 10, C/H = 1.7 × 10, and S/H between 6.0 × 10 and 1.0 × 10. The large number of neutral/protonated species detected allows us to derive the elemental abundances and cosmic ray ionization rate simultaneously. Elemental depletions are estimated to be ~10 for C and O, ~1 for N, and ~25 for S. Conclusions. Barnard B1b presents similar depletions of C and O as those measured in prestellar cores. The depletion of sulfur is higher than that of C and O, but not as extreme as in cold cores. In fact, it is similar to the values found in some bipolar outflows, hot cores, and photon-dominated regions. Several scenarios are discussed to account for these peculiar abundances. We propose that it is the consequence of the initial conditions (important outflows and enhanced UV fields in the surroundings) and a rapid collapse (~0.1 Myr) that allows most S-and N-bearing species to remain in the gas phase to great optical depths. The interaction of the compact outflow associated with B1b-S with the surrounding material could enhance the abundances of S-bearing molecules, as well. © ESO 2016We thank the Spanish MINECO for funding support from grants CSD2009-00038, FIS2012-32096, FIS2014-52172-C2 AYA2012-32032 and ERC under ERC-2013-SyG, G. A. 610256 NANOCOSMOS. E.R. and M.G. thank the INSU/CNRS program PCMI for funding. This research used the facilities of the Canadian Astronomy Data Centre operated by the National Research Council of Canada with the support of the Canadian Space AgencyPeer Reviewe

    Simulación numérica de una cerámica piezoeléctrica

    Full text link
    [EN] In this paper, a mathematical model describing the dynamic behavior of a commercial piezoelectric ceramic, vibrating in thickness, is presented. This model solves, by finite differences, the piezoelectric equations which relate he mechanical and electrical phenomena produced in this kind of material. The behavior in time domain of some physical variables, as the electric field and particle velocity, is simulated too. In addition, we have implemented a GUI in Matlab that allows simple and affordable simulations for all users. The implemented interface provides two kind of study: Broadband and single frequency excitation. The output parameters, obtained after time domain simulation, are piezoelectric constants of the ceramic and the electric response in frequency domain, i.e. admittance and impedance curves. The results allow predicting vibration modes, electrical response and understanding the effect of piezoelectricity on the mechanical response.[ES] En este trabajo se presenta un modelo matemático que describe el comportamiento dinámico de una cerámica piezoeléctrica comercial vibrando en modo espesor. Dicho modelo resuelve, mediante diferencias finitas, las ecuaciones piezoeléctricas que relacionan los fenómenos mecánicos y eléctricos que se producen en este tipo de materiales, y simula el comportamiento de algunas variables físicas puntuales -como campo eléctrico o velocidad de partícula- en el dominio de tiempo. Asimismo, se ha implementado un entorno gráfico en Matlab que permite realizar las simulaciones de forma sencilla y asequible a todos los usuarios. Esta interfaz contempla dos tipos de estudio: excitación de la cerámica en banda ancha y excitación a una sola frecuencia. Como valores de salida el programa facilita, una vez finalizada la simulación de las variables dependientes del tiempo, los distintos parámetros piezoeléctricos de la cerámica y su respuesta eléctrica en el dominio de la frecuencia (curvas de admitancia e impedancia). Los resultados obtenidos permiten, además de predecir los modos propios de vibración y la respuesta eléctrica, comprender el efecto de piezoelectricidad en la respuesta mecánica de un medio material.Este trabajo ha sido financiado por la Universitat Politècnica de València bajo los proyectos PAID 06-10-002-295 y PAID 05-11-002-340González-Salido, N.; Ferri, M.; Jiménez, N.; Camarena, F.; Picó, R.; Redondo, J.; Roig, B. (2013). Simulación numérica de una cerámica piezoeléctrica. Modelling in Science Education and Learning. 6(3):131-144. doi:10.4995/msel.2013.1990SWORD13114463W. G. Hankel. Uber die aktinound piezoelektrischen eigenschaften des bergkrystalles und ihre beziehung zu den thermoelektrischen. Abh. Sächs, 12:457 (1881).Arnau Vives, A. (Ed.). (2004). Piezoelectric Transducers and Applications. doi:10.1007/978-3-662-05361-4T. F. Hueter, R. H. Bolt. Sonics. John Wiley and Sons, Inc, New York, (1955).Ferri, M., Camarena, F., Redondo, J., Picó, R., & Avis, M. R. (2012). Explicit finite-difference time-domain scheme for the simulation of 1-3 piezoelectric effect in axisymmetrical configurations. Wave Motion, 49(6), 569-584. doi:10.1016/j.wavemoti.2012.03.00

    Laboratory and astronomical discovery of the cyanovinyl radical H2CCCN

    Get PDF
    9 pags., 4 figs., 3 tabs.We report the first laboratory and interstellar detection of the alpha-cyano vinyl radical (H2CCCN). This species was produced in the laboratory by an electric discharge of a gas mixture of vinyl cyanide, CH2CHCN, and Ne, and its rotational spectrum was characterized using a Balle-Flygare narrowband-type Fourier-transform microwave spectrometer operating in the frequency region of 8-40 GHz. The observed spectrum shows a complex structure due to tunneling splittings between two torsional sublevels of the ground vibronic state, 0+ and 0-, derived from a large-amplitude inversion motion. In addition, the presence of two equivalent hydrogen nuclei makes necessary to discern between ortho- and para-H2CCCN. A least squares analysis reproduces the observed transition frequencies with a standard deviation of ca. 3 kHz. Using the laboratory predictions, this radical is detected in the cold dark cloud TMC-1 using the Yebes 40m telescope and the QUIJOTE line survey. The 404-303 and 505-404 rotational transitions, composed of several hyperfine components, were observed in the 31.0-50.4 GHz range. Adopting a rotational temperature of 6K we derive a column density of (1.4+/-0.2)e11 cm-2 and (1.1+/-0.2)e11 cm-2 for ortho-H2CCCN and para-H2CCCN, respectively. The reactions C + CH3CN, and perhaps also N + CH2CCH, emerge as the most likely routes to H2CCCN in TMC-1.The present study was supported by ERC through the grant ERC-2013-Syg-610256-NANOCOSMOS, Ministry of Science and Technology of Taiwan through project MOST 104-2113-M-009-202, JSPS KAKENHI through Grant 06640644, and Ministerio de Ciencia e Innovación of Spain through projects PID2019-106110GB-I00, PID2019-107115GBC21/AEI/10.13039/501100011033, and PID2019-106235GB-I00. C.C., M.A, Y.E. and J.C. thank Ministry of Science and Technology of Taiwan and Consejo Superior de Investigaciones Científicas for funding support under the MOSTCSIC Mobility Action 2021 (Grant 11-2927-I-A49-502 and OSTW200006). J.T. thanks the JSPS Postdoctoral Fellowship for Foreign Researchers and Grant-inAid for JSPS Fellows.Peer reviewe

    Herschel Observations of Extraordinary Sources: Analysis of the HIFI 1.2 THz Wide Spectral Survey toward Orion KL. I. Methods

    Get PDF
    We present a comprehensive analysis of a broadband spectral line survey of the Orion Kleinmann-Low nebula (Orion KL), one of the most chemically rich regions in the Galaxy, using the HIFI instrument on board the Herschel Space Observatory. This survey spans a frequency range from 480 to 1907 GHz at a resolution of 1.1 MHz. These observations thus encompass the largest spectral coverage ever obtained toward this high-mass star-forming region in the submillimeter with high spectral resolution and include frequencies >1 THz, where the Earth's atmosphere prevents observations from the ground. In all, we detect emission from 39 molecules (79 isotopologues). Combining this data set with ground-based millimeter spectroscopy obtained with the IRAM 30 m telescope, we model the molecular emission from the millimeter to the far-IR using the XCLASS program, which assumes local thermodynamic equilibrium (LTE). Several molecules are also modeled with the MADEX non-LTE code. Because of the wide frequency coverage, our models are constrained by transitions over an unprecedented range in excitation energy. A reduced χ^2 analysis indicates that models for most species reproduce the observed emission well. In particular, most complex organics are well fit by LTE implying gas densities are high (>10^6 cm^(–3)) and excitation temperatures and column densities are well constrained. Molecular abundances are computed using H_2 column densities also derived from the HIFI survey. The distribution of rotation temperatures, T_(rot), for molecules detected toward the hot core is significantly wider than the compact ridge, plateau, and extended ridge T_(rot) distributions, indicating the hot core has the most complex thermal structure

    Subclinical atherosclerosis burden predicts cardiovascular events in individuals with diabetes and chronic kidney disease

    Get PDF
    Background: Individuals with diabetes have remarkably high rates of cardiovascular morbidity and mortality. However, the incremental cardiovascular risk in diabetes is heterogeneous and has often been related to renal involvement. The purpose of this study was to analyse the prognostic value of subclinical atherosclerosis in determining the incidence of first cardiovascular events (CVEs) in individuals with diabetes and chronic kidney disease (CKD) compared to CKD individuals without diabetes. Methods: We included data from individuals with CKD with and without diabetes, free from pre-existing cardiovascular disease, from the NEFRONA cohort. Participants underwent baseline carotid and femoral ultrasound and were followed up for 4 years. All CVEs during follow-up were registered. Bivariate analysis and Fine-Gray competing risk models were used to perform the statistical analysis. Results: During the mean follow-up time of 48 months, a total of 203 CVE was registered. 107 CVE occurred among participants without diabetes (19.58 per 1000 person-years) and 96 CVE occurred among participants with diabetes (44.44 per 1000 person-years). Following the competing risk analysis, the variables predicting CVEs in CKD individuals without diabetes were the number of territories with plaque at baseline (HR 1.862, 95% CI [1.432;2.240]), age (HR 1.026, 95% CI [1.003;1.049]) and serum concentrations of 25-OH vitamin D (HR 0.963, 95% CI [0.933;0.094]). The only variable predicting CVEs among CKD participants with diabetes was the number of territories with plaque at baseline (HR 1.782, 95% CI [1.393, 2.278]). For both models, concordance (C) index yielded was over 0.7. Conclusions: The burden of subclinical atherosclerosis is the strongest predictor of future CVEs in diabetic individuals with CKD. Early detection of subclinical atherosclerotic burden by multiterritorial vascular ultrasound could improve CVE prediction in this population.Peer reviewe

    New Care Models for Transgender People in the Spanish Health System: Demands, Controversies and Reflections

    Get PDF
    [Resumen] La atención sanitaria a las personas transgénero en España se ha establecido de manera progresiva desde 1999, año en que Andalucía crea la primera unidad multidisciplinar para el tratamiento integral de la reasignación de sexo. Este documento analiza los cambios sociales, las demandas y debates entre usuarios y profesionales y los nuevos modelos de atención sanitaria, y también plantea reflexiones sobre la situación actual. La apertura social en España en la concepción de la diversidad sexual y de género es bastante favorable. Las demandas de los usuarios no son uniformes y no siempre coinciden con los criterios de los profesionales. En algunas comunidades autónomas la asistencia sanitaria se está distanciando del modelo recomendado internacionalmente, que basa la atención en equipos especializados o Unidades de Identidad de Género (UIG). Estos nuevos modelos centran la asistencia en la Atención Primaria, además de en endocrinólogos y pediatras de área sin una evaluación coordinada con Salud Mental. Los principales factores contribuyentes al cambio reciente han sido las demandas desde algunas asociaciones de “despatologización” y “descentralización”. Estos nuevos modelos centran la asistencia en la Atención Primaria, además de en endocrinólogos y pediatras de área sin una evaluación coordinada con Salud Mental. Los profesionales que integran las unidades de género, si bien reconocen la necesidad de una visión amplia de la realidad transgénero, alertan del riesgo que supone tratar a personas trans sin una colaboración de especialistas en Salud Mental o por profesionales de área con escasa experiencia. Además, anticipan que la descentralización no facilita el estudio de grandes cohortes, dificultando el avance del conocimiento y la evaluación contrastada con países del entorno. En resumen, los nuevos modelos sanitarios, aunque ofrecen la atención en proximidad, no garantizan mejoras en la calidad ni promueven el análisis comparado de los resultados.[Abstract] Health care for transgender people in Spain has been progressively established since 1999 when the first multidisciplinary unit for the treatment of sex reassignment was created in Andalusia. In this document, the social changes, the demands and debates of users and professionals, the new models of health care for trans people, and reflections on the current situation, have been analysed. The social openness in Spain regarding sexual and gender diversity has evolved quite positively. The health demands of the transgender users are not uniform and do not always match with the criteria of the professionals. In some Spanish regions, health care is distancing itself from the internationally recommended multidisciplinary model. The new healthcare models have been established under the aegis of primary care and/or endocrinologist in the area, without a required psychological assessment. The main contributing factors for this change of model have been the pressure from some associations with demands for "depathologization" and "decentralization". The professionals of gender units, while recognizing the need for a broader vision of trans reality, warn of the risk of treating trans people without the involvement of mental health specialists or by professionals in proximity with little experience. Moreover, the decentralization would not allow acting on large cohorts, which hinders the advance of knowledge and contrasted evaluations with neighbouring countries. In summary, the new health models, although intended to facilitate care through proximity, do not guarantee improvements in quality and difficult to make a comparative evaluation of the results

    Puntos de encuentro. Investigaciones de posgrado en proceso (II)

    Get PDF
    Puntos de encuentro. Investigaciones de posgrado en proceso (II) es la continuación del proyecto de innovación docente “Puntos de encuentro. Investigaciones de posgrado en proceso” desarrollado durante el curso 2017-18. Dicho proyecto trataba de generar una comunidad de aprendizaje a través de encuentros periódicos, seminarios y actividades comunes entre directores de tesis, profesores y doctorandos. El desarrollo del mismo ha puesto de manifiesto la necesidad de continuar las dinámicas instauradas, así como la articulación de otros posibles modos de ensayar metodologías colaborativas, que son la base de la propuesta. Teniendo en cuenta los resultados obtenidos durante el curso 2017-18 el desarrollo de este proyecto ha estado condicionado por el interés de mantener y propiciar la comunidad de aprendizaje generada. Por otra parte, ha sido fundamental la experimentación en procesos de tutorización entre pares y colectivos, en un periodo formativo definido, en el campo de estudio propuesto por procesos de investigación de carácter individual. El desarrollo de las actividades desarrolladas ha puesto en práctica metodologías colaborativas capaces de ensayar otras aproximaciones a procesos de aprendizaje para las nuevas generaciones de estudiantes. El equipo de trabajo ha estado compuesto por los miembros que ya habían participado en el anterior proyecto (22 doctorandos y 10 docentes) y por nuevas incorporaciones que demostraron interés en formar parte del grupo (28 doctorandos y 14 docentes). En este sentido, cabe destacar que la comunidad no únicamente se ha mantenido sino que se ha visto incrementada. Al igual que el curso anterior el desarrollo de las investigaciones en curso se inscriben en distintos campos de conocimiento afines lo que ha permitido seguir articulando espacios transdisciplinares de encuentro que dieran lugar al debate y al diálogo, así como la creación de redes propiciadas por las afinidades entre distintos miembros del grupo. Esta memoria recoge la valoración de los resultados obtenidos haciendo mención a los objetivos alcanzados, a la metodología empleada, al grupo de trabajo adscrito al proyecto y a las actividades desarrolladas a lo largo del curso 2018-19. Presenta a modo de anexo una serie de imágenes de los encuentros realizados y los documentos de difusión del seminario de investigación
    corecore