9,649 research outputs found

    The Cocoon Nebula and its ionizing star: do stellar and nebular abundances agree?

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    (Abridged) Main sequence massive stars embedded in an HII region should have the same chemical abundances as the surrounding nebular gas+dust. The Cocoon nebula, a close-by Galactic HII region ionized by a narrow line B0.5 V single star (BD+46 3474), is an ideal target to perform a detailed comparison of nebular and stellar abundances in the same Galactic HII region. We investigate the chemical content of O, N and S in the Cocoon nebula from two different points of view: an empirical analysis of the nebular spectrum and a detailed spectroscopic analysis of its ionizing B-type star using state-of-the-art stellar atmosphere modeling. By comparing the stellar and nebular abundances, we aim to indirectly address the long-standing problem of the discrepancy found between abundances obtained from collisionally excited lines (CELs) and optical recombination lines in photoionized nebulae. We collect spatially resolved spectroscopy of the Cocoon nebula and a high resolution optical spectrum of its ionizing star. Standard nebular techniques are used to compute the physical conditions and gaseous abundances of O, N and S. We perform a self-consistent spectroscopic abundance analysis of BD+46 3474 based on the atmosphere code FASTWIND to determine the stellar parameters and Si, O, and N abundances. The Cocoon nebula and its ionizing star, located at a distance of 800+-80 pc, have a very similar chemical composition as the Orion nebula and other B-type stars in the solar vicinity. This result agrees with the high degree of homogeneity of the present-day composition of the solar neighbourhood as derived from the study of the local cold-gas ISM. The comparison of stellar and nebular CELs abundances in the Cocoon nebula indicates that O and N gas+dust nebular values are in better agreement with stellar ones assuming small temperature fluctuations, of the order of those found in the Orion nebula.Comment: Accepted for publication in A&A. 13 pages, 7 tables and 6 figure

    Anorexia nerviosa y psicodrama: intervención a través de la silueta

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    En este artículo se expone el trabajo realizado en un grupo de terapia de mujeres con anorexia nerviosa restrictiva, usuarias de una asociación para personas con trastornos de la conducta alimentaria. A partir de la técnica de la silueta y a través de distintos ejercicios psicodramáticos se trabajó sobre dos factores comunes en los trastornos de la conducta alimentaria: el rechazo al propio cuerpo y la distorsión de la imagen corporal. Este trabajo ayudó a las pacientes a reconocer la distorsión de la imagen corporal que tenían y aceptar que su figura fue la que mostró la silueta real.In this article there will be exposed the work realized in a group of women’s therapy with restrictive anorexia nervosa, users of an Association for persons with disorders of the food conduct. From the technology of the Silhouette, and across different psychodramatic exercises, one was employed on two common factors at the disorders of the food conduct: the rejection to the own body and the distortion of the corporal image. This work helped patients to recognize the body image's distortion that they had and to accept that her figure was the one that showed the actual silhouette

    Enhancing organizational performance with social media use: the catalysing effect of corporate entrepreneurship

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    Social Media use has become pervasive and firms are increasingly relying on it, not only to relate to customers, but also to leverage internal processes like innovation. The strategic use of these tools can facilitate also the entrepreneurial orientation of the firm, as it provides useful knowledge which can make the firm more entrepreneurial, stimulating it to find new opportunities or innovative ideas where other companies do not recognize them. However, despite the relevance of the phenomenon in current hyper-competitive environments, empirical research on the topic remains scarce. To shed some light on the issue, the main purpose of the paper is to examine how Social Media use impacts the different dimensions of corporate entrepreneurship (new business venturing, innovativeness, proactiveness and self-renewal), enhancing also organizational performance. The study is intended to extend knowledge on this topic, by providing understanding of the path firms should take to benefit from Social Media use to become more entrepreneurial and achieve higher organizational performance, developing and nurturing competitive advantages. The paper analyses data obtained from a sample of 201 technological firms located in Spain. The methodology used is Structural equation modelling with LISREL analysis. Findings confirms how the use of Social Media tools positively impacted all the different dimensions of corporate entrepreneurship, translating also in enhanced performance. This paper contributes to the literature by empirically confirming in a structural model how Social Media use helps to create business value, by enhancing proactive behaviours, promoting strategic renewal inside the firm and increasing innovativeness and new business venturing and displaying the internal and sequential relationships among these dimensions.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec
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