Translationally-invariant coupled-cluster method for finite systems

The translational invariant formulation of the coupled-cluster method is presented here at the complete SUB(2) level for a system of nucleons treated as bosons. The correlation amplitudes are solution of a non-linear coupled system of equations. These equations have been solved for light and medium systems, considering the central but still semi-realistic nucleon-nucleon S3 interaction.Comment: 16 pages, 2 Postscript figures, to be published in Nucl. Phys.

Translationally invariant treatment of pair correlations in nuclei: II. Tensor correlations

We study the extension of our translationally invariant treatment of few-body nuclear systems to include tensor forces and correlations. It is shown that a direct application of our method is not as successful for realistic V6 interactions as our previous results for V4 potentials suggested. We investigate the cause in detail for the case of $^4$He, and show that a combination of our method with that of Jastrow-correlated wave functions seems to be a lot more powerful, thereby suggesting that for mildly to strongly repulsive forces such a hybrid procedure may be an appropriate description.Comment: 19 pages, 3 ps figures. uses elsart, graphicx, amssym

Tradición y vanguardia en el Viaje del joven Tobías de Torrente Ballester

El artículo presenta una interpretación de la obra dramática "El viaje del joven Tobías'; primera escrita par Gonzalo Torrente Ballester, como ejemplo de las inquietudes de su época por la renovación de la escena. Estas llevaron en ocasiones a recuperar y adaptar elementos del pasado, como se demostró en la resurrección del género del auto sacramental, incluyera o no los valores del catolicismo. Se señalan coincidencias técnicas o temáticas con obras del momento que expresaban esa misma tendencia a innovar sobre los antiguos esquemas, y asimismo la influencia que sobre los planteamientos y el contenido de la pieza de Torrente ejerce el pensamiento de dos filósofos de gran importancia para la estética de la época, de un modo particular en el ámbito político de la Falange: Eugenio D'Ors y José Ortega y Gasset. This paper puts forward an interpretation of the first play written by Gonzalo Torrente Ballester, Viaje del joven Tobías (Young Tobit’s Journey), which illustrates a widespread concern of his time Adour the renovation of the stage. Such concern conveyed a revival and adaptation of elements from the past, such as the resurrection of the mystery play, not always featuring Catholic values. We highlight the technical or thematic coincidences with contemporary Works expressing a similar tendency to innovation in old patterns, and we similarly stress how thinkers who placed an important role in the period’s aesthetics, particularly within the political context of the Falange: Eugenio D'Ors and José Ortega y Gasset

El impacto de la donación alimentaria sobre la mujer aymara urbana.

Sin resume

Ca impurity in small mixed 4^4He-3^3He clusters

The structure of small mixed helium clusters doped with one calcium atom has been determined within the diffusion Monte Carlo framework. The results show that the calcium atom sits at the $^4$He-$^3$He interface. This is in agreement with previous studies, both experimental and theoretical, performed for large clusters. A comparison between the results obtained for the largest cluster we have considered for each isotope shows a clear tendency of the Ca atom to reside in a deep dimple at the surface of the cluster for $^4$He clusters, and to become fully solvated for $^3$He clusters. We have calculated the absorption spectrum of Ca around the $4s4p \leftarrow 4s^2$ transition and have found that it is blue-shifted from that of the free-atom transition by an amount that depends on the size and composition of the cluster.Comment: 24 pages, 11 figures. Accepted on Journal of Chemical Physic

Two-dimensional molecular para-hydrogen and ortho-deuterium at zero temperature

We study molecular para-hydrogen (p-${\rm H_{2}}$) and ortho-deuterium (o-${\rm D_{2}}$) in two dimensions and in the limit of zero temperature by means of the diffusion Monte Carlo method. We report energetic and structural properties of both systems like the total and kinetic energy per particle, radial pair distribution function, and Lindemann's ratio in the low pressure regime. By comparing the total energy per particle as a function of the density in liquid and solid p-${\rm H_{2}}$, we show that molecular para-hydrogen, and also ortho-deuterium, remain solid at zero temperature. Interestingly, we assess the quality of three different symmetrized trial wave functions, based on the Nosanow-Jastrow model, in the p-${\rm H_{2}}$ solid film at the variational level. In particular, we analyze a new type of symmetrized trial wave function which has been used very recently to describe solid $^{4}$He and found that also characterizes hydrogen satisfactorily. With this wave function, we show that the one-body density matrix $\varrho_{1} (r)$ of solid p-${\rm H_{2}}$ possesses off-diagonal long range order, with a condensate fraction that increases sizably in the negative pressure regime.Comment: 11 pages, 9 figure

Microscopic study of the He2-SF6 trimers

The He2-SF6 trimers, in their different He isotopic combinations, are studied both in the framework of the correlated Jastrow approach and of the Correlated Hyperspherical Harmonics expansion method. The energetics and structure of the He-SF6 dimers are analyzed, and the existence of a characteristic rotational band in the excitation spectrum is discussed, as well as the isotopic differences. The binding energies and the spatial properties of the trimers, in their ground and lowest lying excited states, obtained by the Jastrow ansatz are in excellent agreement with the results of the converged CHH expansion. The introduction of the He-He correlation makes all trimers bound by largely suppressing the short range He-He repulsion. The structural properties of the trimers are qualitatively explained in terms of the shape of the interactions, Pauli principle and masses of the constituents.Comment: 17 pages, 5 figures. Submitted to PR

Determination of total plasma hydroperoxides using a diphenyl-1- pyrenylphosphine fluorescent probe

Plasma hydroperoxides (HPs) are widely accepted to be good indicators of oxidative stress. By means of the method proposed here, which uses diphenyl-1-pyrenylphosphine (DPPP) as a fluorescent probe, all types of plasma HP were determined. The limits of detection and quantification of the method were 0.08 and 0.25 nmol of cumene hydroperoxide (CHP) equivalents in 40 μl of plasma, respectively. The method is satisfactory in terms of precision (5.3% for 14.5 μM CHP eq., n = 8), and the recoveries were 91% and 92% after standard additions of 26 and 52 μM CHP, respectively. The selectivity of the proposed method is higher than 96%. Moreover, optimization of the reaction conditions and the addition of ethylenediaminetetraacetic acid (EDTA) disodium salt and 2,6-di-tert-butyl-4-methylphenol (BHT) prevented the formation of HP artifacts during the analysis. Therefore, the proposed method is useful for simple and quantitative determination of total plasma HPs. © 2012 Elsevier Inc. All rights reserved.Peer Reviewe

State-dependent Jastrow correlation functions for 4He nuclei

We calculate the ground-state energy for the nucleus 4He with V4 nucleon interactions, making use of a Jastrow description of the corresponding wavefunction with state-dependent correlation factors. The effect related to the state dependence of the correlation is quite important, lowering the upper bound for the ground-state energy by some 2 MeV.Comment: 10 pages, REVTeX, to be published in J. Phys. G: Nucl. Part. Phy

Circular microwave tomographic imaging. Experimental comparison between quantitative and qualitative algorithms

The iterative Time Domain Inversion tomographic algorithm (TDI) proposed by Chalmers University of Technology is compared in terms of image quality to the UWB Magnitude Combined tomographic algorithm (MC-UWB) proposed by the Universitat Politcnica de Catalunya (UPC). The first is able to provide quantitative permittivity images of the object under test, while the second provides quantitative images, being its major strength the short reconstruction time (real time) and robustness. The comparison between the algorithms will be performed based on experimental measurements acquired with two tomographic setups, available at both universities. The Chalmers setup provides a short acquisition time but a narrow band behavior due to the monopole antennas, while the UPC setup is slower but uses broadband antennas