11,787 research outputs found
ChPT parameters from tau-decay data
Using the updated ALEPH V-A spectral function from tau decays, we determine
the lowest spectral moments of the left-right correlator and extract dynamical
information on order parameters of the QCD chiral symmetry breaking.
Uncertainties associated with violations of quark-hadron duality are estimated
from the data, imposing all known short-distance constraints on a
resonance-based parametrization. Employing proper pinched weight functions, we
obtain an accurate determination of the effective chiral couplings L10 and C87
and the dimension-six and -eight contributions in the Operator Product
Expansion.Comment: 5 pages, 3 figures, QCD2015 Montpellie
Errores en la sustracción cometidos por estudiantes universitarios
El manejo adecuado de las operaciones elementales es uno de los objetivos de la enseñanza obligatoria de gran parte de los países del mundo. Referido a ello, la investigación muestra que un alto porcentaje de niños de primaria (6-12 años) cometen errores cuando realizan sustracciones (López y Sánchez, 2007; Young y O’Shea, 1981). Sin embargo apenas se sabe si esos errores se mantienen en personas adultas. En este trabajo se pretende analizar los tipos de errores que estudiantes universitarios cometen al realizar la sustracción
Inner and outer star forming regions over the disks of spiral galaxies. I. Sample characterization
Context. The knowledge of abundance distributions is central to understanding
the formation and evolution of galaxies. Most of the relations employed for the
derivation of gas abundances have so far been derived from observations of
outer disk HII regions, despite the known differences between inner and outer
regions. Aims. Using integral field spectroscopy (IFS) observations we aim to
perform a systematic study and comparison of two inner and outer HII regions
samples. The spatial resolution of the IFS, the number of objects and the
homogeneity and coherence of the observations allow a complete characterization
of the main observational properties and differences of the regions. Methods.
We analyzed a sample of 725 inner HII regions and a sample of 671 outer HII
regions, all of them detected and extracted from the observations of a sample
of 263 nearby, isolated, spiral galaxies observed by the CALIFA survey.
Results. We find that inner HII regions show smaller equivalent widths, greater
extinction and luminosities, along with greater values of
[NII]{\lambda}6583/H{\alpha} and [OII]{\lambda}3727/[OIII]{\lambda}5007
emission-line ratios, indicating higher metallicites and lower ionization
parameters. Inner regions have also redder colors and higher photometric and
ionizing masses, although Mion/Mphot is slighty higher for the outer regions.
Conclusions. This work shows important observational differences between inner
and outer HII regions in star forming galaxies not previously studied in
detail. These differences indicate that inner regions have more evolved stellar
populations and are in a later evolution state with respect to outer regions,
which goes in line with the inside-out galaxy formation paradigm.Comment: 16 page
Deep into the Water Fountains: The case of IRAS 18043-2116
(Abridged) The formation of large-scale (hundreds to few thousands of AU)
bipolar structures in the circumstellar envelopes (CSEs) of post-Asymptotic
Giant Branch (post-AGB) stars is poorly understood. The shape of these
structures, traced by emission from fast molecular outflows, suggests that the
dynamics at the innermost regions of these CSEs does not depend only on the
energy of the radiation field of the central star. Deep into the Water
Fountains is an observational project based on the results of programs carried
out with three telescope facilities: The Karl G. Jansky Very Large Array
(JVLA), The Australia Telescope Compact Array (ATCA), and the Very Large
Telescope (SINFONI-VLT). Here we report the results of the observations towards
the WF nebula IRAS 180432116: Detection of radio continuum emission in the
frequency range 1.5GHz - 8.0GHz; HO maser spectral features and radio
continuum emission detected at 22GHz, and H ro-vibrational emission lines
detected at the near infrared. The high-velocity HO maser spectral
features, and the shock-excited H emission detected could be produced in
molecular layers which are swept up as a consequence of the propagation of a
jet-driven wind. Using the derived H column density, we estimated a
molecular mass-loss rate of the order of Myr. On the
other hand, if the radio continuum flux detected is generated as a consequence
of the propagation of a thermal radio jet, the mass-loss rate associated to the
outflowing ionized material is of the order of 10Myr.
The presence of a rotating disk could be a plausible explanation for the
mass-loss rates estimated.Comment: 10 pages, 5 figures. Accepted for publication in A&
Flux-cutting and flux-transport effects in type-II superconductor slabs in a parallel rotating magnetic field
The magnetic response of irreversible type-II superconductor slabs subjected
to in-plane rotating magnetic field is investigated by applying the circular,
elliptic, extended-elliptic, and rectangular flux-line-cutting critical-state
models. Specifically, the models have been applied to explain experiments on a
PbBi rotating disk in a fixed magnetic field , parallel to the flat
surfaces. Here, we have exploited the equivalency of the experimental situation
with that of a fixed disk under the action of a parallel magnetic field,
rotating in the opposite sense. The effect of both the magnitude of the
applied magnetic field and its angle of rotation upon the
magnetization of the superconductor sample is analyzed. When is smaller
than the penetration field , the magnetization components, parallel and
perpendicular to , oscillate with increasing the rotation angle. On
the other hand, if the magnitude of the applied field, , is larger than
, both magnetization components become constant functions of at
large rotation angles. The evolution of the magnetic induction profiles inside
the superconductor is also studied.Comment: 12 pages, 29 figure
Diavideos: a Diabetes Health Video Portal
Diavideos1 is a web platform that collects trustworthy
diabetes health videos from YouTube and offers them in a easy
way. YouTube is a big repository of health videos, but good
content is sometimes mixed with misleading and harmful
videos such as promoting anorexia [1].Diavideos is a web
portal that provides easy access to a repository of trustworthy
diabetes videos. This poster describes Diavideos and explains
the crawling method used to retrieve these videos from trusted
channels
Influence of coach encouragement on technical demand of an small-sided games in football-7.
El objetivo del presente estudio ha sido analizar el efecto de la motivación del entrenador sobre la demanda técnica de un juego reducido (JR) 3 contra 3, realizado por futbolistas de categoría alevín, observando el nivel de aprendizaje técnico adquirido a través de estas tareas.
Se han cuantificado el número de acciones técnicas que se producen en un JR de 3 contra 3 sin intervención del entrenador (JRSIE) y las que se producen en el mismo JR con la intervención del entrenador (JRCME). Se ha realizado en cada una de las 4 sesiones del programa de entrenamiento con JR dos test de valoración del dominio técnico en situaciones pre y post sesión.
Los resultados confirman que aparecen diferencias en el número de acciones técnicas que el jugador realiza durante el JR, siendo significativamente mayor en el JRCME, generándose además mayor nivel de aprendizaje
Relación entre los serotipos de lengua azul y su vector, en Europa y cuenca mediterránea
La Lengua Azul es una enfermedad de distribución mundial que afecta a rumiantes y se transmite a través de la picadura de las hembras del mosquito del Género Culicoides. Tradicionalmente, la enfermedad ha estado ligada a la presencia del mosquito Culicoides imicola, pero estudios recientes apuntan a una posible implicación de otras especies de mosquitos que puedan sobrevivir en regiones más frías. Utilizando un sistema de visualización geográfica ARCGIS 9.2 (ESRI®) se ha podido representar la distribución de las principales especies de Culicoides implicadas en la transmisión de Lengua Azul en Europa y norte de África y compararlo con el mapa de distribución de los serotipos del virus de la Lengua Azul. El análisis de los mapas realizados prueba que Culicoides imicola está relacionado con la transmisión de los serotipos 1, 2, 4, 9 y 16 y que el complejo Obsoletus transmite el serotipo 8 y podría ser capaz de transmitir otros serotipos del virus con los que hasta ahora no ha tenido contacto.Bluetongue (BT) is a worldwide spread disease affecting ruminants, which is transmitted by the biting of female midges from the Genus Culicoides. Traditionally, this disease has been linked with the presence of the midge Culicoides imicola, but, recent studies have suggested the possibility of other midge species being involved in the transmission of Bluetongue in cooler regions. By applying the geographic information system ARCGIS 9.2 (ESRI®), the distribution of the main Culicoides species involved in Blue Tongue transmission in Europe and the North of Africa and the distribution of BT serotypes in the same region has been represented. The analysis of the maps obtained shows that Culicoides imicola is involved in the transmission of Bluetongue serotypes 1, 2, 4, 9 and 16 and the Obsoletus complex could be able to transmit, besides BTV-8, other BT serotypes with which it has never been in contact so far
Integral Field Spectroscopy of HH 262: The Spectral Atlas
HH 262 is a group of emitting knots displaying an "hour-glass" morphology in
the Halpha and [SII] lines, located 3.5' to the northeast of the young stellar
object L1551-IRS5, in Taurus. We present new results of the kinematics and
physical conditions of HH 262 based on Integral Field Spectroscopy covering a
field of 1.5'x3', which includes all the bright knots in HH 262. These data
show complex kinematics and significant variations in physical conditions over
the mapped region of HH 262 on a spatial scale of <3". A new result derived
from the IFS data is the weakness of the [NII] emission (below detection limit
in most of the mapped region of HH 262), including the brightest central knots.
Our data reinforce the association of HH 262 with the redshifted lobe of the
evolved molecular outflow L1551-IRS5. The interaction of this outflow with a
younger one, powered by L1551 NE, around the position of HH 262 could give rise
to the complex morphology and kinematics of HH 262.Comment: Accepted for publication in MNRA
Overview of ASDEX Upgrade results
The ASDEX Upgrade (AUG) programme is directed towards physics input to critical
elements of the ITER design and the preparation of ITER operation, as well as addressing
physics issues for a future DEMO design. Since 2015, AUG is equipped with a new pair of
3-strap ICRF antennas, which were designed for a reduction of tungsten release during ICRF
operation. As predicted, a factor two reduction on the ICRF-induced W plasma content could
be achieved by the reduction of the sheath voltage at the antenna limiters via the compensation
of the image currents of the central and side straps in the antenna frame. There are two main
operational scenario lines in AUG. Experiments with low collisionality, which comprise
current drive, ELM mitigation/suppression and fast ion physics, are mainly done with freshly
boronized walls to reduce the tungsten influx at these high edge temperature conditions. Full
ELM suppression and non-inductive operation up to a plasma current of Ip = 0.8 MA could
be obtained at low plasma density. Plasma exhaust is studied under conditions of high neutral
divertor pressure and separatrix electron density, where a fresh boronization is not required.
Substantial progress could be achieved for the understanding of the confinement degradation
by strong D puffing and the improvement with nitrogen or carbon seeding. Inward/outward
shifts of the electron density profile relative to the temperature profile effect the edge stability
via the pressure profile changes and lead to improved/decreased pedestal performance.
Seeding and D gas puffing are found to effect the core fueling via changes in a region of high
density on the high field side (HFSHD).
The integration of all above mentioned operational scenarios will be feasible and
naturally obtained in a large device where the edge is more opaque for neutrals and higher
plasma temperatures provide a lower collisionality. The combination of exhaust control
with pellet fueling has been successfully demonstrated. High divertor enrichment values of
nitrogen EN 10 have been obtained during pellet injection, which is a prerequisite for the
simultaneous achievement of good core plasma purity and high divertor radiation levels.
Impurity accumulation observed in the all-metal AUG device caused by the strong neoclassical
inward transport of tungsten in the pedestal is expected to be relieved by the higher
neoclassical temperature screening in larger devices.European Commission (EUROfusion 633053
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