746 research outputs found
An Expanding HI Photodissociated Region Associated with the Compact HII Region G213.880-11.837 in the GGD 14 Complex
We present high angular and spectral resolution HI 21~cm line observations
toward the cometary-shaped compact HII region G213.880-11.837 in the GGD~14
complex.The kinematics and morphology of the photodissociated region, traced by
the HI line emission, reveal that the neutral gas is part of an expanding flow.
The kinematics of the HI gas along the major axis of G213.880-11.837 shows that
the emission is very extended toward the SE direction, reaching LSR radial
velocities in the tail of about 14 km/s. The ambient LSR radial velocity of the
molecular gas is 11.5 km/s, which suggests a champagne flow of the HI gas. This
is the second (after G111.61+0.37) cometary HII/HI region known.Comment: Accepted for publication in the Astronomical Journal (10 pages, 4
figures, 1 table
Aprendizaje basado en problemas en Biología Vegetal
El aprendizaje basado en problemas (ABP) es un método de enseñanzaaprendizaje
que usa el problema como punto de partida para la adquisición e
integración de nuevos conocimientos. En el desarrollo del ABP el problema es el
camino para que los estudiantes alcancen los objetivos de conocimientos,
destrezas y habilidades. El ABP y el estudio de casos se centran en el estudiante
lo cual implica necesariamente un cambio de función en el profesor que deja de
ser protagonista para convertirse en una guía o en tutor. El tutor plantea
problemas y cuestiones que contribuyen al entendimiento y a la resolución de
problemas promoviendo de esta forma un aprendizaje significativo. Por otra
parte, las nuevas tecnologías de la información y la comunicación introducen
cambios importantes en el proceso de enseñanza-aprendizaje en base a lo
siguiente: a) el acceso a la información y el modo de adquirir información, b) las
nuevas formas de relación profesor-alumno. Este trabajo muestra algunas
experiencias para el desarrollo de ABP, el estudio de casos y la elaboración de
mapas conceptuales e infografías, experiencias realizadas en el aula con
estudiantes de Biología de la Universidad Complutense de Madrid y en relación
con dos campos de la Biología: la Fisiología Vegetal y la Biología Evolutiva.The problem-based learning (PBL) is a teaching-learning method that uses
the problem as a starting point for the acquisition and integration of new
knowledge. In the development of PBL the problem is the way to achieve the
knowledge, skills and abilities. Problem-based learning and case study focuses
on the student and therefore imply a change in the teacher role: from protagonist
to tutor or guide. A tutor offers questions that contribute to understanding and
managing the problem promoting meaningful learning. On the other hand,
information and communication technologies introduces important changes in
teaching and learning on the basis of two issues: a) access and how to acquire
information, b) new forms of teacher-student relationship. This work shows
some experiences for the development of PBL, case studies and concept mapping
as classroom experiences for Biological Sciences students at the Complutense
University of Madrid. Two biological sciences fields were considered: plant
physiology and evolutionary plant biology
Residual Forage and Animal Performance from a Kikuyo Pasture under Mixed Grazing and Supplementation
Five grazing strategies were compared: grazing by ewes only and mixed grazing (ewes + heifers), in mixed grazing heifers received no supplement or one of three supplements. Ruminal undegradable protein (RUP) varied among supplement: 4.25, 9.11 and 9.13%, the supplement with the highest RUP included protected methionine. All supplements were 21% crude protein and 3.0 Mcal/kg of metabolizable energy. Grazing was on kikuyu, ratio was 30 kg of ewe per 100 kg of heifer in the mixed grazing treatments. Experimental grazing lasted 84 days. Variables measured were residual forage, proline content in residual forage and liveweight gains per animal and per hectare. Experimental design was a completely random with two replicates. Residual forage was the highest (P\u3c 0.05) in mixed grazing and RUP in supplement was above 4.25%. The highest (P\u3c 0.05) proline content was found in grazing by ewes only, 52% above the proline content found in mixed grazing without supplement, when heifers received supplement proline content decreased (P\u3c 0.05) further. Grazing by ewes only and mixed grazing with heifersreceiving the highest RUP in supplement showed the highest (P\u3c 0.05) daily liveweight gain per ewe of 134 g. Mixed grazing in which heifers received no supplement gave a 100% increase (P\u3c 0.05) in liveweight gain per hectare compared to grazing by ewes only. In mixed grazing offering a supplement with 9.13% RUP and protected methionine gave both the highest liveweight gains per animal and per hectare. It was concluded that mixed grazing allowed a lower stress level on kikuyu due to defoliation and a higher liveweight gain per hectare than grazing by ewes only
A survey of SiO 5-4 emission towards outflows from massive young stellar objects
Results are presented of a survey of SiO 5-4 emission observed with the James
Clerk Maxwell Telescope (JCMT) towards a sample of outflows from massive young
stellar objects. The sample is drawn from a single-distance study by Ridge &
Moore. In a sample of 12 sources, the 5-4 line was detected in 5, a detection
rate of 42 per cent. This detection rate is higher than that found for a sample
of low-luminosity outflow sources, although for sources of comparable
luminosity, it is in good agreement with the results of a previous survey of
high luminosity sources. For most of the detected sources, the 5-4 emission is
compact or slightly extended along the direction of the outflow. NGC6334I shows
a clear bipolar flow in the 5-4 line. Additional data were obtained for
W3-IRS5, AFGL5142 and W75N for the 2-1 transition of SiO using the
Berkeley-Illinois-Maryland Association (BIMA) millimetre interferometer. There
is broad agreement between the appearance of the SiO emission in both lines,
though there are some minor differences. The 2-1 emission in AFGL5142 is
resolved into two outflow lobes which are spatially coincident on the sky, in
good agreement with previous observations. In general the SiO emission is
clearly associated with the outflow. The primary indicator of SiO 5-4
detectability is the outflow velocity, i.e. the presence of SiO is an indicator
of a high velocity outflow. This result is consistent with the existence of a
critical shock velocity required to disrupt dust grains and subsequent SiO
formation in post-shock gas. There is also weak evidence that higher luminosity
sources and denser outflows are more likely to be detected.Comment: Accepted for publication in MNRA
Un nuevo concepto de la gastronomía desde la bioeconomía y la actividad académica
El proyecto “Ciencia y arte en gastronomía: botánica gastronómica y
gastronomía molecular” se está desarrollando con el objetivo de establecer y
organizar el intercambio de conocimientos y negocio en este ámbito. Con este
objetivo se pretende aunar el conocimiento científico con la salud y el bienestar
social desde la perspectiva bioeconómica promoviendo la creación de riqueza y
trabajo. El proyecto forma parte de los cursos especializados que la Universidad
Complutense de Madrid oferta con el animo de incrementar el conocimiento y
desarrollar competencias personales y profesionales. El programa responde a la
demanda social proporcionando una formación con inmediata proyección
profesional mediante el establecimiento de un nexo directo entre la actividad
académica y la realidad social.Universidad de Sevilla. Cristalografía, Mineralogía y Química Agrícola
The project "Science and art in gastronomy: gastronomic botany and
molecular gastronomy" is being developed with the aim to establish and organize
the exchange of knowledge and business in this area. In this way we are working
to join the scientific knowledge to the health and the social well-being, without
losing the current perspective from the bioeconomy which look forward the generation of wealth and work. The project belongs to specialized courses
offered by The Complutense University of Madrid which aim is to update the
knowledge and develop personal and professional competitions. These programs
answer to a social demand on providing formation with professional immediate
projection establishing a direct relation between the academic activity and the
social reality
The distance to the Orion Nebula
We have used the Very Long Baseline Array to measure the trigonometric
parallax of several member stars of the Orion Nebula Cluster showing
non-thermal radio emission. We have determined the distance to the cluster to
be 414 +/- 7 pc. Our distance determination allows for an improved calibration
of luminosities and ages of young stars. We have also measured the proper
motions of four cluster stars which, when accurate radial velocities are
measured, will put strong constraints on the origin of the cluster.Comment: 13 pages, 3 figures, to appear in Astronomy & Astrophyisc
A wide-angle outflow with the simultaneous presence of a high-velocity jet in the high-mass Cepheus A HW2 system
We present five epochs of VLBI water maser observations around the massive
protostar Cepheus A HW2 with 0.4 mas (0.3 AU) resolution. The main goal of
these observations was to follow the evolution of the remarkable water maser
linear/arcuate structures found in earlier VLBI observations. Comparing the
data of our new epochs of observation with those observed five years before, we
find that at "large" scales of > 1" (700 AU) the main regions of maser emission
persist, implying that both the surrounding medium and the exciting sources of
the masers have been relatively stable during that time span. However, at
smaller scales of < 0.1" (70 AU) we see large changes in the maser structures,
particularly in the expanding arcuate structures R4 and R5. R4 traces a nearly
elliptical patchy ring of ~ 70 mas size (50 AU) with expanding motions of ~ 5
mas/yr (15 km/s). This structure is probably driven by the wind of a still
unidentified YSO located at the centre of the ring (~ 0.18" south of HW2). On
the other hand, the R5 expanding bubble structure (driven by the wind of a
previously identified YSO located ~ 0.6" south of HW2) is currently dissipating
in the circumstellar medium and losing its previous degree of symmetry,
indicating a very short-lived event. In addition, our results reveal, at scales
of ~ 1" (700 AU), the simultaneous presence of a relatively slow (~ 10-70 km/s)
wide-angle outflow (opening angle of ~ 102 deg, traced by the masers, and the
fast (~ 500~km/s) highly collimated radio jet associated with HW2 (opening
angle of ~ 18 deg, previously observed with the VLA. This simultaneous presence
of a wide-angle outflow and a highly collimated jet associated with a massive
protostar is similar to what is found in some low-mass YSOs. The implications
of these results in the study of the formation of high-mass stars are
discussed.Comment: 28 pages, 7 figures. Animations will be included as supporting
material online (MNRAS web page
Radio sources at low Galactic latitudes
We present high-resolution radio observations of a sample of 65 radio sources
at low Galactic latitudes. The sources were all observed at 5 GHz with the Very
Large Array A-array. MERLIN observations at 5 GHz of the ultracompact HII
region G34.26+0.15 and one of the extragalactic sources, B1857-000, are also
presented, as are GMRT observations of HI in the direction of three sources,
B1801-203, B1802-196 and B1938+229. These observations were made with the
objectives of (i) finding compact components suitable for studying the effects
of interstellar scattering at lower frequencies, (ii) identifying high
surface-brightness lobes of background radio sources to probe the Galactic
magnetic field on different scales via polarization observations, and (iii)
searching for young supernova remnants. We discuss the nature of the sources
found to have shell or shell-like structure and exhibiting both thermal and
non-thermal spectra. Of the remaining sources, B1749-281 is coincident within
the positional errors of a known pulsar, not detected earlier at 5 GHz. The
rest are likely to be background extragalactic objects.Comment: 12 pages, 6 figures (most with multiple images), 1 table. Accepted
for publicaton in MNRA
Gestión de residuos sólidos urbanos en San Isidro Mazatepec, Tala
En este proyecto PAP verano 2018 San Isidro Mazatepec, nos enfocamos en generar un plan de gestión de residuos sólidos urbanos. Participó un equipo multidisciplinario conformado por ingenieros industriales, mecánicos, licenciados en relaciones industriales y en administración. La base del proyecto fue la problemática que existe en el poblado de San Isidro Mazatepec sobre la excesiva producción de residuos sólidos urbanos, la falta de espacios en donde realizar los depósitos de basura y la deplorable situación del sistema de gestión actual, así como del relleno sanitario del poblado. Se atacó la problemática desde la estrategia de implementación de un sistema de gestión de residuos, en donde se acondicionó un centro de acopio, en donde se acumularán los residuos sólidos urbanos de todo el poblado, se separarán y se tratarán para su futura venta y/o reciclaje. Estudiamos la situación de la bodega en materia de espacios, y realizamos un lay–out (diseño) del acomodo interno, para optimizar de la mejor manera los espacios, movimientos y procesos. Asimismo, se fabricaron prototipo de botes de basura en los que se separaran los residuos; esto se logró realizando una investigación por parte del delegado del pueblo, acordando la mejor ubicación para éstos. Lo anterior se validó mediante herramientas estadísticas y la opinión de un grupo representativo de habitantes de San Isidro. Por último, gestionamos una campaña de limpieza, a manera de concientización de la población, y poner en funcionamiento el centro de acopio.ITESO, A.C
Discovery potential of xenon-based neutrinoless double beta decay experiments in light of small angular scale CMB observations
The South Pole Telescope (SPT) has probed an expanded angular range of the CMB temperature power spectrum. Their recent analysis of the latest cosmological data prefers nonzero neutrino masses, mnu = 0.32+-0.11 eV. This result, if confirmed by the upcoming Planck data, has deep implications on the discovery of the nature of neutrinos. In particular, the values of the effective neutrino mass involved in neutrinoless double beta decay (bb0nu) are severely constrained for both the direct and inverse hierarchy, making a discovery much more likely. In this paper, we focus in xenon-based bb0nu experiments, on the double grounds of their good performance and the suitability of the technology to large-mass scaling. We show that the current generation, with effective masses in the range of 100 kg and conceivable exposures in the range of 500 kg year, could already have a sizable opportunity to observe bb0nu events, and their combined discovery potential is quite large. The next generation, with an exposure in the range of 10 ton year, would have a much more enhanced sensitivity, in particular due to the very low specific background that all the xenon technologies (liquid xenon, high-pressure xenon and xenon dissolved in liquid scintillator) can achieve. In addition, a high-pressure xenon gas TPC also features superb energy resolution. We show that such detector can fully explore the range of allowed effective Majorana masses, thus making a discovery very likely
- …