424 research outputs found
One-loop corrections for WW to HH in Higgs EFT with the electroweak chiral Lagrangian
In this work, we present the computation of the one-loop electroweak radiative corrections to the scattering process WW → HH within the context of the Higgs Effective Field Theory (HEFT). We assume that the fermionic interactions are like in the Standard Model, whereas the beyond Standard Model interactions in the bosonic sector are given by the electroweak chiral Lagrangian (EChL). The computation of the one-loop amplitude and the renormalization program is performed in terms of the involved one-particle-irreducible (1PI) functions and using Rζ covariant gauges. The renormalization of 1PI functions at arbitrary external momenta is a more ambitious program than just renormalizing the amplitude with on-shell external legs, and it has the advantage that they can be used in several scattering amplitudes. In fact, we use here some of the 1PI functions already computed in our previous work (devoted to WZ → WZ). We will complement them here with the computation of the new 1PI functions required for WW → HH. From this renormalization procedure, we will also derive the full set of renormalized coefficients of the EChL that are relevant for this scattering process. In the last part, we will present the numerical results for the EChL predictions of the one-loop level cross section, σ(WW → HH)|1-loop, as a function of the center-of-mass energy, showing the relative size of the one-loop radiative corrections with respect to the tree-level prediction in terms of the EChL coefficients. The results of the one-loop corrections to WW → HH for the SM case will be also presented, for comparison with the EChL case, following the same computational method - i.e., by means of the renormalization of 1PI function
Influence of an ultrathin GaAs interlayer on the structural properties of InAs/InGaAsP/InP (100) quantum dots investigated by cross-sectional scanning tunneling microscopy
Cross-sectional scanning tunneling microscopy is used to study at the atomic scale how the structural properties of InAsInGaAsPInP quantum dots _QDs_ are modified when an ultrathin _0–1.5 ML_ GaAs interlayer is inserted underneath the QDs. Deposition of the GaAs interlayer suppresses the influence of the AsP exchange reaction on QD formation and leads to a planarized QD growth surface. A shape transition from quantum dashes, which are strongly dissolved during capping, to well defined QDs takes place when increasing the GaAs interlayer thickness between 0 and 1.0 ML. Moreover, the GaAs interlayer allows the control of the AsP exchange reaction, reducing the QD height for increased GaAs thicknesses above 1.0 ML, and decreases the QD composition intermixing, producing almost pure InAs QDs
Static scheduling of the LU factorization with look-ahead on asymmetric multicore processors
[EN] We analyze the benefits of look-ahead in the parallel execution of the LU factorization with partial pivoting (LUpp) in two distinct "asymmetric" multicore scenarios. The first one corresponds to an actual hardware-asymmetric architecture such as the Samsung Exynos 5422 system-on-chip (SoC), equipped with an ARM big.LITTLE processor consisting of a quad core Cortex-A15 cluster plus a quad-core Cortex-A7 cluster. For this scenario, we propose a careful mapping of the different types of tasks appearing in LUpp to the computational resources, in order to produce an efficient architecture-aware exploitation of the computational resources integrated in this SoC. The second asymmetric configuration appears in a hardware-symmetric multicore architecture where the cores can individually operate at a different frequency levels. In this scenario, we show how to employ the frequency slack to accelerate the tasks in the critical path of LUpp in order to produce a faster global execution as well as a lower energy consumption. (C) 2018 Elsevier B.V. All rights reserved.The researchers from Universidad Jaume I were supported by projects TIN2014-53495-R and TIN2017-82972-R of MINECO and FEDER, and the FPU program of MECD. The researcher from Universitat Politecnica de Catalunya was supported by projects TIN2015-65316-P of MINECO and FEDER and 2017-SGR-1414 from the Generalitat de Catalunya.Catalán, S.; Herrero, JR.; Quintana OrtÃ, ES.; RodrÃguez-Sánchez, R. (2018). Static scheduling of the LU factorization with look-ahead on asymmetric multicore processors. Parallel Computing. 76:18-27. https://doi.org/10.1016/j.parco.2018.04.006S18277
Irrigation from the Sixties: Flumen-Monegros
53 Pags.- Tabls.- Maps.In arid and semiarid areas, agricultural land use is mainly restricted, in the first place, by the
availability of water for crop growth.
The transformation to irrigation of about 600 000 ha in the Ebro Valley has led to high
increases in yield and in diversity of crops.
After the Spanish Civil War (1936-39), which was followed by II World War, the Spanish
food production system was heavily disrupted and food shortages appeared. This put high
pressure on the development of new irrigated schemes which had been planned many
years ago.
In the Flumen-Monegros area, the technology available in the late fifties was based on
flood-irrigation systems, with no previous soil studies, an empirical land evaluation, no
control of saltinization risk and, finally, levelling without topsoil preservation.
The extension of salinity and/or sodicity-affected soils in the Ebro Valley (IRYDA, 1977) was
200 000 ha, from which 160 000 were located in Aragon, mainly in Bardenas, Cinca and
Flumen-Monegros area. But Alberto et al. (1984) reckron this data in 300 000 ha. As a
result of these studies, ILACO (1975) designed two experimental drainage plots.
Although the existence of salt-affected soils was known, information about the extent,
location and general functioning at landscape level of those soils was lacking in the area.
Some of the problems related to land use and soil management which are present now in
the area or can be expected in the near future are:- Salinity-Sodicity: Diagnosis, monitoring and rehabilitation of salt-affected soils.
- Soil structural degradation and surface crust formation.
- Need for improved efficiency in water use: irrigation technology, water reuse, ...
- Control of drainage-system degradation: open-air drains as well as underground drains.
Several approaches at different scales have been adopted to work on these issues.
Satellite images have been used to monitor land use and its temporal variability. Classical
soil mapping at 1: 100000 level have been performed; in addition various detailed studies
have been undertaken in model areas using the electromagnetic and four electrode
sensors, micromorphological techniques, scanning electronic microscopy, and land
evaluation procedures.
The results have been presented in several papers: about salinity-sodicity trends in the
Flumen sector (Herrero, 1987); about parameters related to water behaviour (Aragues,
1986); about soil porosity in plough horizons (Rodriguez-Ochoa, 1998); about translocation
of solid materials (Rodriguez-Ochoa, et al. 1989; Porta and Rodriguez-Ochoa, 1991;
Rodriguez-Ochoa, 1998); about degradation of underground drainage systems by mineral
siltation (Herrero et al. 1989; Rodriguez-Ochoa, et al. 1989; Munoz, 1991; RodriguezOchoa,
1998).Other studies performed in the area include: Soil-vegetation relationships (Herrero, 1981);
laboratory trials with different amendments in the drainage trench infilling material (Porta et
al. 1996); dispersive processes because of soil structural instability (Amezketa and
Aragues, 1990; Aragues and Amezketa, 1991; Amezketa and Aragues, 1995) and
degradation of the hydraulic conductivity of soils (Amezketa and Aragues, 1989; Aragues
and Amezketa, 1991; Amezketa and Aragues, 1995).
The trip to the Flumen-Monegros area undertakes some of these points, and the stops are
located in some of the main soil units.
Discussion will be centered on aspects of soil genesis, classification and mapping, land use
and soil conservation.Peer reviewe
Mechanical and optical properties of ultralarge flakes of a metal-organic framework with molecular thickness
The isolation of 2D-materials is already a success for graphene, graphene oxide, boron nitride and a few clays or metal chalcogenides, however despite the fact that some of them show very interesting physical properties, they lack useful functionalities. Metal-Organic Frameworks (MOFs) are multifunctional materials showing a wide range of physical and chemical properties that can be structurally designed by suitable selection of their building-blocks. This strategy may allow the production of layers with a variety of useful electronic and molecular recognition functionalities. Herein we isolate 2D-MOF flakes with areas of hundreds of square microns and an excellent control of the molecular thickness (from single up to ca. 50 layers). The samples exhibit such good photoluminescence and mechanical properties as to allow free-standing characterization of few layers' flakesThe authors acknowledge financial support from MICINN (MAT2013-46753-C2-1-P and MAT2013-46753-C2-2-P and Consolider CSD2010-00024
Análisis del estado de tensiones en uniones carpinteras de empalme de llave por el método de los elementos finitos
El objeto del presente trabajo es la determinación de la distribución de tensiones en la unión carpintera de empalme de llave mediante el método de los elementos finitos y su comparación con los valores obtenidos mediante la teorÃa de Resistencia de Materiales. Se analizan las zonas donde se produce concentración de tensiones y se estudia la influencia del refino de la malla sobre los resultados con el fin de determinar el tamaño que proporciona los valores de tensión más ajustados a la teorÃa. En las zonas donde la concentración de tensiones es menor, distintos tamaños de la malla muestran valores de tensión similares. Los resultados muestran una simetrÃa central de la distribución de isotensiones donde el centro de simetrÃa se corresponde con el centro geométrico de la unión. En las zonas donde se produce concentración de tensiones, los valores de las mismas aumentan considerablemente con el refino de la malla. La comparación de los niveles de tensiones normales obtenidos por el MEF y la teorÃa clásica muestran diferencias reducidas, excepto en los puntos de concentración de tensiones. The purpose of this study is to determine the stress distribution in the joint carpenter of halved and tabled joint with the finite element method and its comparison with the values obtained using the theory of Strength of Materials. The stress concentration areas where analyzed and the influence of mesh refinement was studied on the results in order to determine the mesh size that provides the stress values more consistent with the theory. In areas where stress concentration is lower, different mesh sizes show similar stress values. The results show a central symmetry of the isobar lines distribution where the centre of symmetry corresponds to the geometric centre of the joint. In areas where stress concentration occurs, the same values increase considerably with the refinement of the mesh. Comparison of normal stress levels obtained by the FEM and the classical theory shows small differences, except at points of stress concentration
- …