568 research outputs found
High Resolution Observations of the Massive Protostar in IRAS18566+0408
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
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"
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 de desarrollo de Software que optan por trabajar con la metodología ágil como Scrum, centran sus esfuerzos en la entrega frecuente 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 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
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 (1 mJy) and
compact (0.6) 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 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
We present a high sensitivity radio continuum survey at 6 and 1.3cm 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 mJy level. Due to the improvement in the continuum
sensitivity of the VLA, this survey achieved map rms levels of 3-10
Jy beam at sub-arcsecond angular resolution. We extracted 70
centimeter continuum sources associated with 1.2mm 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 12,000AU and 4,000AU,
respectively. We calculated 5 - 25GHz 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
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, NH, and
CHOH 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
25GHz CHOH transitions toward ten sources; five of them also show
NH emission. We found that most of the sources detected in CHOH and
NH have been classified as ionized jets or jet candidates and that the
emission lines are coincident with, or very near ( 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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