565 research outputs found

    High Resolution Observations of the Massive Protostar in IRAS18566+0408

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    We report 3 mm continuum, CH3CN(5-4) and 13CS(2-1) line observations with CARMA, in conjunction with 6 and 1.3 cm continuum VLA data, and 12 and 25 micron broadband data from the Subaru Telescope toward the massive proto-star IRAS18566+0408. The VLA data resolve the ionized jet into 4 components aligned in the E-W direction. Radio components A, C, and D have flat cm SEDs indicative of optically thin emission from ionized gas, and component B has a spectral index alpha = 1.0, and a decreasing size with frequency proportional to frequency to the -0.5 power. Emission from the CARMA 3 mm continuum, and from the 13CS(2-1), and CH3CN(5-4) spectral lines is compact (i.e. < 6700 AU), and peaks near the position of VLA cm source, component B. Analysis of these lines indicates hot, and dense molecular gas, typical for HMCs. Our Subaru telescope observations detect a single compact source, coincident with radio component B, demonstrating that most of the energy in IRAS18566+0408 originates from a region of size < 2400 AU. We also present UKIRT near-infrared archival data for IRAS18566+0408 which show extended K-band emission along the jet direction. We detect an E-W velocity shift of about 10 km/sec over the HMC in the CH3CN lines possibly tracing the interface of the ionized jet with the surrounding core gas. Our data demonstrate the presence of an ionized jet at the base of the molecular outflow, and support the hypothesis that massive protostars with O-type luminosity form with a mechanism similar to lower mass stars

    Narrativas y prácticas dialógicas de los docentes que posibilitan que el estudiante aparezca como otro legítimo en la convivencia

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    The purpose of this article is to evidence the documentary review carried out around the narratives and dialogic practices of teachers that make it possible for the student to appear as a legitimate other in coexistence. The importance of the subject in the educational field comes from its philosophical link based on one's own perspective, by that of the "other", leaving without effect the particular "I". A qualitative type of research was carried out, with a documentary design supported by a systematic review. Thirty research studies were selected (from databases such as Google Scholar, Dialnet, Scopus, Latindex and University Repositories). For the systematization of the information, a matrix was created where the documents were registered according to their characteristics. From the selected categories, four axes emerged, which are presented structured in trends that emerged from the review, referring to the conception of narrative and dialogic practice, the relationship between philosophy and education, public policies and diversity in the school environment and the normative route of inclusion. The findings reveal the need to generate inclusive and innovative learning environments that eliminate learning barriers and achieve more opportunities for equality for all from the classroom with teachers and students.El presente artículo tiene como propósito evidenciar la revisión documental realizada alrededor de las narrativas y prácticas dialógicas de los docentes que posibilitan que el estudiante aparezca como otro un legítimo en la convivencia. La importancia del tema en el campo educativo parte de su vinculación filosófica basado en la propia perspectiva, por la del “otro”, dejando sin efecto el “yo” particular. Se realizó una investigación de tipo cualitativo, con diseño documental apoyado en la revisión sistemática. Se seleccionaron 30 investigaciones (provenientes de bases de datos como Google académico, Dialnet, Scopus, Latindex y Repositorios de Universidades). Para la sistematización de la información se creó una matriz donde se realizó el registro de los documentos según sus características. Desde las categorías seleccionadas emergieron cuatro ejes que se presentan estructurados en tendencias que surgieron de la revisión referidos a concepción de narrativa y práctica dialógica, relación filosofía y educación, políticas públicas y diversidad en el ámbito escolar y la ruta normativa de la inclusión. Los hallazgos dejan ver la necesidad de generar ambientes de aprendizaje incluyentes e innovadores, que eliminen las barreras de aprendizaje y logren más oportunidades de igualdad para todos desde el aula con maestros y estudiantes

    Technical Writer: A proposal to improve quality and documentation in the agile methodology "Scrum"

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    Software development companies that choose to work with the agile Scrum methodology focus their efforts on frequent product delivery, neglecting the documentation itself of the processes involved in development. Scrum teams are made up of highly trained technicians in whom trust is placed for the development of a software solution. To support the Scrum team in documentation issues, we propose to incorporate a new actor called Technical Writer into the team, who will be in charge from the beginning of carrying the documentation that merits according to the phases of software development, which will contribute to the delivery of a final product with quality and with the respective documentation. We conclude that although the documentation is not the strength of the agile Scrum methodology, it is very necessary to deliver a quality product to its customers. Resumen. Las empresas&nbsp; de&nbsp; desarrollo&nbsp; de&nbsp; Software&nbsp; que&nbsp; optan&nbsp; por&nbsp; trabajar&nbsp; con la metodología ágil como Scrum, centran sus esfuerzos en la entrega frecuente&nbsp; y priorizada de productos, descuidando en gran medida la documentación que se genera en sí durante los procesos inmersos en el desarrollo de software. Normalmente, los equipos de Scrum están conformados por técnicos altamente capacitados que&nbsp; se orientan completamente al desarrollo de una solución software. Para apoyar al equipo Scrum en temas de documentación y elaboración de artefactos de software, proponemos incorporar dentro del equipo a un nuevo actor que lo hemos denominado: “Technical Writer”, quien se encargará de llevar la documentación desde el principio del proceso Scrum y en las actividades donde se amerite en las fases del desarrollo del software. La propuesta apunta a que los técnicos del equipo Scrum aporten de mejor manera en la entrega de un producto final con calidad y con una adecuada documentación. Concluimos que a pesar de que la documentación no es el fuerte de la metodología ágil Scrum, es muy necesaria para entregar un producto de calidad a sus clientes

    Weak and Compact Radio Emission in Early High-Mass Star Forming Regions: II. The Nature of the Radio Sources

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    In this study we analyze 70 radio continuum sources associated with dust clumps and considered to be candidates for the earliest stages of high-mass star formation. The detection of these sources was reported by Rosero et al. (2016), who found most of them to show weak (<{\scriptstyle <}1 mJy) and compact (<{\scriptstyle <}\,0.6^{\prime \prime}) radio emission. Herein, we used the observed parameters of these sources to investigate the origin of the radio continuum emission. We found that at least 30%\sim 30\% of these radio detections are most likely ionized jets associated with high-mass protostars, but for the most compact sources we cannot discard the scenario that they represent pressure-confined HII regions. This result is highly relevant for recent theoretical models based on core accretion that predict the first stages of ionization from high-mass stars to be in the form of jets. Additionally, we found that properties such as the radio luminosity as a function of the bolometric luminosity of ionized jets from low and high-mass stars are extremely well-correlated. Our data improve upon previous studies by providing further evidence of a common origin for jets independently of luminosity.Comment: Accepted for publication in the Ap

    Weak and Compact Radio Emission in Early High-Mass Star Forming Regions: I. VLA Observations

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    We present a high sensitivity radio continuum survey at 6 and 1.3\,cm using the Karl G. Jansky Very Large Array towards a sample of 58 high-mass star forming regions. Our sample was chosen from dust clumps within infrared dark clouds with and without IR sources (CMC-IRs, CMCs, respectively), and hot molecular cores (HMCs), with no previous, or relatively weak radio continuum detection at the 11\,mJy level. Due to the improvement in the continuum sensitivity of the VLA, this survey achieved map rms levels of \sim 3-10 μ\muJy beam1^{-1} at sub-arcsecond angular resolution. We extracted 70 centimeter continuum sources associated with 1.2\,mm dust clumps. Most sources are weak, compact, and are prime candidates for high-mass protostars. Detection rates of radio sources associated with the mm dust clumps for CMCs, CMC-IRs and HMCs are 6%\%, 53%\% and 100%\%, respectively. This result is consistent with increasing high-mass star formation activity from CMCs to HMCs. The radio sources located within HMCs and CMC-IRs occur close to the dust clump centers with a median offset from it of 12,000\,AU and 4,000\,AU, respectively. We calculated 5 - 25\,GHz spectral indices using power law fits and obtain a median value of 0.5 (i.e., flux increasing with frequency), suggestive of thermal emission from ionized jets. In this paper we describe the sample, observations, and detections. The analysis and discussion will be presented in Paper II.Comment: Accepted for publication in the ApJ

    Broadband VLA Spectral Line Survey of a Sample of Ionized Jet Candidates

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    The study of the interaction between ionized jets, molecular outflows and their environments is critical to understanding high-mass star formation, especially because jets and outflows are thought to be key in the transfer of angular momentum outwards from accretion disks. We report a low-spectral resolution VLA survey for hydrogen radio recombination lines, OH, NH3_3, and CH3_3OH lines toward a sample of 58 high-mass star forming regions that contain numerous ionized jet candidates. The observations are from a survey designed to detect radio continuum; the novel aspect of this work is to search for spectral lines in broadband VLA data (we provide the script developed in this work to facilitate exploration of other datasets). We report detection of 25\,GHz CH3_3OH transitions toward ten sources; five of them also show NH3_3 emission. We found that most of the sources detected in CH3_3OH and NH3_3 have been classified as ionized jets or jet candidates and that the emission lines are coincident with, or very near (0.1\lesssim 0.1 pc) these sources, hence, these molecular lines could be used as probes of the environment near the launching site of jets/outflows. No radio recombination lines were detected, but we found that the RMS noise of stacked spectra decreases following the radiometer equation. Therefore, detecting radio recombination lines in a sample of brighter free-free continuum sources should be possible. This work demonstrates the potential of broadband VLA continuum observations as low-resolution spectral line scans.Comment: 38 pages, 19 figures. Accepted for publication in The Astrophysical Journal Supplement Serie
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