11,841 research outputs found
Gamow-Teller and double-beta decays of heavy nuclei within an effective theory
We study decays within an effective theory that treats nuclei as a
spherical collective core with an even number of neutrons and protons that can
couple to an additional neutron and/or proton. First we explore Gamow-Teller
decays of parent odd-odd nuclei into low-lying ground-, one-, and
two-phonon states of the daughter even-even system. The low-energy constants of
the effective theory are adjusted to data on decays to ground states or
Gamow-Teller strengths. The corresponding theoretical uncertainty is estimated
based on the power counting of the effective theory. For a variety of
medium-mass and heavy isotopes the theoretical matrix elements are in good
agreement with experiment within the theoretical uncertainties. We then study
the two-neutrino double- decay into ground and excited states. The
results are remarkably consistent with experiment within theoretical
uncertainties, without the necessity to adjust any low-energy constants.Comment: 17 pages, 5 figures, results extended to two-neutrino double
beta-minus decays and two-neutrino double electron-capture decays to excited
2+ states, matches published versio
Autophagy is activated and involved in cell death with participation of cathepsins during stress-induced microspore embryogenesis in barley
Microspores are reprogrammed towards embryogenesis by stress. Many microspores die after this stress, limiting the efficiency of microspore embryogenesis. Autophagy is a degradation pathway that plays critical roles in stress response and cell death. In animals, cathepsins have an integral role in autophagy by degrading autophagic material; less is known in plants. Plant cathepsins are papain-like C1A cysteine proteases involved in many physiological processes, including programmed cell death. We have analysed the involvement of autophagy in cell death, in relation to cathepsin activation, during stress-induced microspore embryogenesis in Hordeum vulgare. After stress, reactive oxygen species (ROS) and cell death increased and autophagy was activated, including HvATG5 and HvATG6 up-regulation and increase of ATG5, ATG8, and autophagosomes. Concomitantly, cathepsin L/F-, B-, and H-like activities were induced, cathepsin-like genes HvPap-1 and HvPap-6 were up-regulated, and HvPap-1, HvPap-6, and HvPap-19 proteins increased and localized in the cytoplasm, resembling autophagy structures. Inhibitors of autophagy and cysteine proteases reduced cell death and promoted embryogenesis. The findings reveal a role for autophagy in stress-induced cell death during microspore embryogenesis, and the participation of cathepsins. Similar patterns of activation, expression, and localization suggest a possible connection between cathepsins and autophagy. The results open up new possibilities to enhance microspore embryogenesis efficiency with autophagy and/or cysteine protease modulators.España, MINECO AGL2014-52028-R and AGL2017-82447-
Numerical analysis of rapid drawdown: applications in real cases
In this study, rapid drawdown scenarios were analyzed by means of numerical examples as well as modeling of real cases with in situ measurements. The aim of the study was to evaluate different approaches available for calculating pore water pressure distributions during and after a drawdown. To do that, a single slope subjected to a drawdown was first analyzed under different calculation alternatives, and numerical results were discussed. Simple methods, such as undrained analysis and pure flow analysis, implicitly assuming a rigid soil skeleton, lead to significant errors in pore water pressure distributions when compared with coupled flow-deformation analysis. A similar analysis was performed for the upstream slope of the Glen Shira Dam, Scotland, and numerical results were compared with field measurements during a controlled drawdown. Field records indicate that classical undrained calculations are conservative but unrealistic. Then, a recent case of a major landslide triggered by a rapid drawdown in a reservoir was interpreted. A key aspect of the case was the correct characterization of permeability of a representative soil profile. This was achieved by combining laboratory test results and a back analysis of pore water pressure time records during a period of reservoir water level fluctuations. The results highlight the difficulty of predicting whether the pore water pressure is overestimated or underestimated when using simplified approaches, and it is concluded that predicting the pore water pressure distribution in a slope after a rapid drawdown requires a coupled flow-deformation analysis in saturated and unsaturated porous media.Peer ReviewedPostprint (published version
Evaluation of a Fall Alerting System based on a Convolutional Deep Neural Network
ArtĂculo sobre detecciĂłn de caĂdas con redes neuronales profundasOwing to the effects of falls on quality of life of the elderly, automatic fall detection systems (FDS) have become a key research topic in the ambit of telecare. This works assesses the performance of convolutional neural networks when they are applied to identify fall accidents in a wearable FDS provided with a tri-axial accelerometer. The evaluation of the detection algorithm is carried out by employing a benchmarking repository with a wide set of traces captured from a wide group of volunteers that executed a programmed series of Activities of the Daily Living (ADLs) and emulated falls. Results show that the CNN can properly distinguish both types of movements with a success rate (specificity and sensitivity) around 99%.Universidad de Málaga. Campus de Excelencia Internacional AndalucĂa Tech
Criteria for rapid sliding I.: a review of Vaiont case
Vaiont slide has been represented by a model of two interacting evolutive wedges. Mass conservation during the motion implies that the upper wedge transfers mass to the lower one through an internal shearing plane. The model respects available in situ observations. It was formulated in dynamics terms. Outcomes of the analysis are the determination of safety factors of the valley before dam impoundment, and the calculation of run-out distance once the motion starts. Rock strength degradation as motion develops has also been included. This degradation, even if it is intense, was unable to explain the very high estimated landslide velocities.Peer ReviewedPostprint (author's final draft
Slope stability in slightly fissured claystones and marls
The final publication is available at Springer via http://dx.doi.org/10.1007/s10346-014-0526-5The paper deals with the behavior of some characteristic soft rocks found in the Iberian Peninsula. In geological terms, they belong to Tertiary basins, the Keuper period and the Jurassic-Cretacic transition. The discussion is organized around the following aspects: (a) the intact material and its brittle behavior; (b) the weathering action of atmospheric events; (c) the persistent discontinuities and scale effects; and (d) the modification of strength after failure. In all cases, instability phenomena are addressed in connection with several case histories. Regarding material brittleness and the initial stress state, two cases of first time failures are discussed. Practical implications concerning the selection of operative strength will be given. Field observations of the relevance of weathering and, also, on the rate of weathering, are given for a Weald claystone. Field observations emphasize the importance of sharp transitions between weathered and intact (or slightly weathered) levels. A recent long-term laboratory investigation on the nature of degradation will be summarized. Macroscopic variables such as stiffness and tensile strength have been found to be uniquely predicted by a degradation law in terms of the accumulated plastic deformations. Persistent discontinuities and, in particular, sedimentation planes play a dominant role to explain slope failures not related to the shallow failures, usually associated with weathered profiles. The strength of discontinuities in a Weald formation was investigated by means of tests performed at two scales. Finally, the evolution in time of residual strength induced by chemical actions, associated with groundwater flow, is highlighted in connection with actual field data of unstable slopes.Peer ReviewedPostprint (author's final draft
Criteria for rapid sliding II.: thermo-hydro-mechanical and scale effects in Vaiont case
Thermally induced excess pore pressures have been included into a two-wedge evolutive model of Vaiont landslide. The problem requires the solution of a system of four coupled balance equations for the shear bands and the surrounding rock as well as the joint equation of motion of the entire slide. The model predicts the high velocities observed and is consistent with other data (slide geometry, residual strength, and conditions on the sliding surface). The interpretation of a sensitivity analysis suggests that there exists a threshold permeability band, in the range 10- 8 to 10- 10 m/s, which separates potentially fast motions from slow motions. This conclusion is maintained if the scale of the landslide is reduced.Peer ReviewedPostprint (author's final draft
El lenguaje de la puesta en escena: el texto teatral, un texto escrito por muchas manos
La aparente sencillez del teatro esconde una gran complejidad. El espectáculo teatral es un
texto escrito por muchas manos. El encuentro entre el actor, que interpreta el texto previo de
un dramaturgo, y el espectador requiere la complicidad de éste. El espectáculo se completa
precisamente porque el espectador conoce y acepta la convenciĂłn teatral y participa de ella a
través de lo que se ha llamado la suspensión de la incredulidad. Pero también el actor rellena
los huecos que ofrece un texto. Su fisico, su voz, su edad, su apostura fisica construyen una
historia que sólo de una manera esquemática adivinábamos en el texto. La elección del actor
y su trabajo condicionan al dramaturgo cuando escribe y, a la vez, estos elementos están condicionados
precisamente por el imaginario colectivo del espectador. Desde hace un siglo hay
que añadir a este esquema la figura del director, a quien hoy consideramos el principal
creador del espectáculo, hasta el punto de que se habla ya de los derechos de autor de la dirección
de escena.Seemingly, theatre appears to be simple, but it hides a great complexity. Performance is a text
written by many hands. The meeting between the actor, who plays a previous text, and the
audience requires the complicity of the latter. The show completes itself through the audience's
knowledge of theatre conventions, and its willing participating in the suspension of disbelief.
But the actor also filling in the holes found in all dramatical works. His physical presence,
voice and age build up a story that was somehow unfinished in the written text. The
choice of the actor and his performance determine the author's performance as well; moreover,
all these factors are conditioned by the collective imagination of the audience. Since the
beginning of the last century, the director of the play has appeared to be the main creator
behind the show, so much so that it is even argued that there should be a copyright for the
mise en scéne.Publicad
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