36 research outputs found
Does ict resources improve the sport teaching processes in handball?
La motivación (M) y la capacidad de percepción-análisis (PA) del juego, variables del proceso de enseñanza-aprendizaje, fueron evaluadas tras utilizar diferentes recursos durante las explicaciones del entrenador. 71 jugadores(Sub-18) fueron divididos en dos grupos: G1 (n=35): recursos tradicionales; G2 (n=36): recursos multimedia. Se evaluó el nivel inicial (i) y final (f), tras 10 sesiones de entrenamiento.
Ambas variables mejoraron significativamente en ambos grupos. Fueron mayores las mejoras del G2 en ambas variables (p<.001). Se hallaron únicamente diferencias intergrupales en la evaluación final en M y PA (p<.001), mostrando el Grupo 2 mejores resultados.
Se concluye que la utilización de recursos multimedia posee un efecto positivo mayor que los recursos tradicionales sobre M y PA en jugadores de balonmano (Sub-18).Motivation (M) and game perception-analysis ability (PA), variables in the teaching-learning process, were evaluated after using different resources during the coach’s explanations. Seventy-one players (Under-18) were divided into 2 groups: G1 (n = 35) traditional resources; G2 (n = 36) multimedia resources. Initial (i) and final (f) levels of both variables were evaluated after 10 training sessions.
Both variables showed a significant improvement in both groups. The improvements shown in G2 were greater in both variables (p<0.001). Intergroup differences were only found in the final evaluation in M and PA (p<0,001), where G2 obtained better results.
It was concluded that using multimedia resources has a greater positive effect than traditional resources on M and PA in under-18 handball players
The distribution and origin of C₂H in NGC 253 from ALCHEMI
Context. Observations of chemical species can provide insights into the physical conditions of the emitting gas however it is important to understand how their abundances and excitation vary within different heating environments. C2H is a molecule typically found in PDR regions of our own Galaxy but there is evidence to suggest it also traces other regions undergoing energetic processing in extragalactic environments. /
Aims. As part of the ALCHEMI ALMA large program, we map the emission of C2H in the central molecular zone of the nearby starburst galaxy NGC 253 at 1.6″ (28 pc) resolution and characterize it to understand its chemical origins. /
Methods. We used spectral modeling of the N = 1−0 through N = 4−3 rotational transitions of C2H to derive the C2H column densities towards the dense clouds in NGC 253. We then use chemical modeling, including photodissociation region (PDR), dense cloud, and shock models to investigate the chemical processes and physical conditions that are producing the molecular emission. /
Results. We find high C2H column densities of ∼1015 cm−2 detected towards the dense regions of NGC 253. We further find that these column densities cannot be reproduced if it is assumed that the emission arises from the PDR regions at the edge of the clouds. Instead, we find that the C2H abundance remains high even in the high visual extinction interior of these clouds and that this is most likely caused by a high cosmic-ray ionization rate
Reconstructing the shock history in the CMZ of NGC 253 with ALCHEMI
Context: HNCO and SiO are well-known shock tracers and have been observed in nearby galaxies, including the nearby (D = 3.5 Mpc) starburst galaxy NGC 253. The simultaneous detection of these two species in regions where the star-formation rate is high may be used to study the shock history of the gas. //
Aims: We perform a multi-line molecular study of NGC 253 using the shock tracers SiO and HNCO and aim to characterize its gas properties. We also explore the possibility of reconstructing the shock history in the central molecular zone (CMZ) of the galaxy. //
Methods: Six SiO transitions and eleven HNCO transitions were imaged at high resolution 1.″6 (28 pc) with the Atacama Large Millimeter/submillimeter Array (ALMA) as part of the ALCHEMI Large Programme. Both non local thermaldynamic equilibrium (non-LTE) radiative transfer analysis and chemical modeling were performed in order to characterize the gas properties and investigate the chemical origin of the emission. //
Results: The nonLTE radiative transfer analysis coupled with Bayesian inference shows clear evidence that the gas traced by SiO has different densities and temperatures than that traced by HNCO, with an indication that shocks are needed to produce both species. Chemical modeling further confirms such a scenario and suggests that fast and slow shocks are responsible for SiO and HNCO production, respectively, in most GMCs. We are also able to infer the physical characteristics of the shocks traced by SiO and HNCO for each GMC. //
Conclusions: Radiative transfer and chemical analysis of the SiO and HNCO in the CMZ of NGC 253 reveal a complex picture whereby most of the GMCs are subjected to shocks. We speculate on the possible shock scenarios responsible for the observed emission and provide potential history and timescales for each shock scenario. Observations of higher spatial resolution for these two species are required in order to quantitatively differentiate between the possible scenarios
Sensitivity of a tonne-scale NEXT detector for neutrinoless double beta decay searches
The Neutrino Experiment with a Xenon TPC (NEXT) searches for the neutrinoless
double-beta decay of Xe-136 using high-pressure xenon gas TPCs with
electroluminescent amplification. A scaled-up version of this technology with
about 1 tonne of enriched xenon could reach in less than 5 years of operation a
sensitivity to the half-life of neutrinoless double-beta decay decay better
than 1E27 years, improving the current limits by at least one order of
magnitude. This prediction is based on a well-understood background model
dominated by radiogenic sources. The detector concept presented here represents
a first step on a compelling path towards sensitivity to the parameter space
defined by the inverted ordering of neutrino masses, and beyond.Comment: 22 pages, 11 figure
Reconstructing the shock history in the CMZ of NGC 253 with ALCHEMI
HNCO and SiO are well known shock tracers and have been observed in nearby
galaxies, including the nearby (D=3.5 Mpc) starburst galaxy NGC 253. The
simultaneous detection of these two species in regions where the star formation
rate is high may be used to study the shock history of the gas. We perform a
multi-line molecular study using these two shock tracers (SiO and HNCO) with
the aim of characterizing the gas properties. We also explore the possibility
of reconstructing the shock history in NGC 253's Central Molecular Zone (CMZ).
Six SiO transitions and eleven HNCO transitions were imaged at high resolution
(28 pc) with the Atacama Large Millimeter/submillimeter Array (ALMA) as
part of the ALCHEMI Large Programme. Both non-LTE radiative transfer analysis
and chemical modelling were performed in order to characterize the gas
properties, and to investigate the chemical origin of the emission. The non-LTE
radiative transfer analysis coupled with Bayesian inference shows clear
evidence that the gas traced by SiO has different densities and temperatures
than that traced by HNCO, with an indication that shocks are needed to produce
both species. Chemical modelling further confirms such a scenario and suggests
that fast and slow shocks are responsible for SiO and HNCO production,
respectively, in most GMCs. We are also able to infer the physical
characteristics of the shocks traced by SiO and HNCO for each GMC. Radiative
transfer and chemical analysis of the SiO and HNCO in the CMZ of NGC 253 reveal
a complex picture whereby most of the GMCs are subjected to shocks. We
speculate on the possible shock scenarios responsible for the observed emission
and provide potential history and timescales for each shock scenario. Higher
spatial resolution observations of these two species are required in order to
quantitatively differentiate between scenarios
Kinematics of Galactic Centre clouds shaped by shear-seeded solenoidal turbulence
The Central Molecular Zone (CMZ; the central ~ 500 pc of the Galaxy) is a
kinematically unusual environment relative to the Galactic disc, with high
velocity dispersions and a steep size-linewidth relation of the molecular
clouds. In addition, the CMZ region has a significantly lower star formation
rate (SFR) than expected by its large amount of dense gas. An important factor
in explaining the low SFR is the turbulent state of the star-forming gas, which
seems to be dominated by rotational modes. However, the turbulence driving
mechanism remains unclear. In this work, we investigate how the Galactic
gravitational potential affects the turbulence in CMZ clouds. We focus on the
CMZ cloud G0.253+0.016 (`the Brick'), which is very quiescent and unlikely to
be kinematically dominated by stellar feedback. We demonstrate that several
kinematic properties of the Brick arise naturally in a cloud-scale
hydrodynamics simulation that takes into account the Galactic gravitational
potential. These properties include the line-of-sight velocity distribution,
the steepened size-linewidth relation, and the predominantly solenoidal nature
of the turbulence. Within the simulation, these properties result from the
Galactic shear in combination with the cloud's gravitational collapse. This is
a strong indication that the Galactic gravitational potential plays a crucial
role in shaping the CMZ gas kinematics, and is a major contributor to
suppressing the SFR by inducing predominantly solenoidal turbulent modes.Comment: 7 pages, 8 figures; accepted to MNRAS (July 24th 2023
Sensitivity of a tonne-scale NEXT detector for neutrinoless double-beta decay searches
The Neutrino Experiment with a Xenon TPC (NEXT) searches for the neutrinoless double-beta (0¿ßß) decay of 136Xe using high-pressure xenon gas TPCs with electroluminescent amplification. A scaled-up version of this technology with about 1 tonne of enriched xenon could reach in less than 5 years of operation a sensitivity to the half-life of 0¿ßß decay better than 1027 years, improving the current limits by at least one order of magnitude. This prediction is based on a well-understood background model dominated by radiogenic sources. The detector concept presented here represents a first step on a compelling path towards sensitivity to the parameter space defined by the inverted ordering of neutrino masses, and beyond. [Figure not available: see fulltext.] © 2021, The Author(s)
Boosting background suppression in the NEXT experiment through Richardson-Lucy deconvolution
Next-generation neutrinoless double beta decay experiments aim for half-life
sensitivities of ~ yr, requiring suppressing backgrounds to <1
count/tonne/yr. For this, any extra background rejection handle, beyond
excellent energy resolution and the use of extremely radiopure materials, is of
utmost importance. The NEXT experiment exploits differences in the spatial
ionization patterns of double beta decay and single-electron events to
discriminate signal from background. While the former display two Bragg peak
dense ionization regions at the opposite ends of the track, the latter
typically have only one such feature. Thus, comparing the energies at the track
extremes provides an additional rejection tool. The unique combination of the
topology-based background discrimination and excellent energy resolution (1%
FWHM at the Q-value of the decay) is the distinguishing feature of NEXT.
Previous studies demonstrated a topological background rejection factor of ~5
when reconstructing electron-positron pairs in the Tl 1.6 MeV double
escape peak (with Compton events as background), recorded in the NEXT-White
demonstrator at the Laboratorio Subterr\'aneo de Canfranc, with 72% signal
efficiency. This was recently improved through the use of a deep convolutional
neural network to yield a background rejection factor of ~10 with 65% signal
efficiency. Here, we present a new reconstruction method, based on the
Richardson-Lucy deconvolution algorithm, which allows reversing the blurring
induced by electron diffusion and electroluminescence light production in the
NEXT TPC. The new method yields highly refined 3D images of reconstructed
events, and, as a result, significantly improves the topological background
discrimination. When applied to real-data 1.6 MeV pairs, it leads to a
background rejection factor of 27 at 57% signal efficiency.Comment: Submitted to JHE