Scaling Evolution of Universal Dark-Matter Halo Density Profiles

Dark-matter halos show a universal density profile with a scaling such that less massive systems are typically denser. This mass-density relation is well described by a proportionality between the characteristic density of halos and the mean cosmic density at halo formation time. It has recently been shown that this proportionality could be the result of the following simple evolutionary picture. Halos form in major mergers with essentially the same, cosmogony-dependent, dimensionless profile, and then grow inside-outside, as a consequence of accretion. Here we verify the consistency of this picture and show that it predicts the correct zero point of the mass-density relation.Comment: 9 pages, 1 Table and 1 postscript figure, latex uses aaspp4.sty, accepted for publication in The Astrophysical Journal Letter

Heuristics for Longest Edge Selection in Simplicial Branch and Bound

Pre-print de la comunicacion presentada al ICCSA2015Simplicial partitions are suitable to divide a bounded area in branch and bound. In the iterative re nement process, a popular strategy is to divide simplices by their longest edge, thus avoiding needle-shaped simplices. A range of possibilities arises in higher dimensions where the number of longest edges in a simplex is greater than one. The behaviour of the search and the resulting binary search tree depend on the se- lected longest edge. In this work, we investigate different rules to select a longest edge and study the resulting efficiency of the branch and bound algorithm.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Double Entropic Stochastic Resonance

We demonstrate the appearance of a purely entropic stochastic resonance (ESR) occurring in a geometrically confined system, where the irregular boundaries cause entropic barriers. The interplay between a periodic input signal, a constant bias and intrinsic thermal noise leads to a resonant ESR-phenomenon in which feeble signals become amplified. This new phenomenon is characterized by the presence of two peaks in the spectral amplification at corresponding optimal values of the noise strength. The main peak is associated with the manifest stochastic resonance synchronization mechanism involving the inter-well noise-activated dynamics while a second peak relates to a regime of optimal sensitivity for intra-well dynamics. The nature of ESR, occurring when the origin of the barrier is entropic rather than energetic, offers new perspectives for novel investigations and potential applications. ESR by itself presents yet another case where one constructively can harvest noise in driven nonequilibrium systems.Comment: 6 pages, 7 figures ; Europhys. Lett., in press (2009

Homogenization of the one-dimensional wave equation

We present a method for two-scale model derivation of the periodic homogenization of the one-dimensional wave equation in a bounded domain. It allows for analyzing the oscillations occurring on both microscopic and macroscopic scales. The novelty reported here is on the asymptotic behavior of high frequency waves and especially on the boundary conditions of the homogenized equation. Numerical simulations are reported

Strain quantification related to the Berzosa/fault (Spanish Central System)

[Resumen] En relación con la zona de cizalla dúctil de Berzosa Honrubia que actúa durante la segunda fase de deformación Hercínica, se han calculado los elipsoides de deformación finita asociados a la misma. Para el cálculo se usan los métodos de Ramsay (1967), Dunnet (1969), y Fry (1979). Los resultados muestran una variación en el tipo de elipsoide a lo largo de la traza de la zona de cizalla. En los extremos tienen valores K>t, y en la parte central de Kl en la región donde son paralelos.[Abstract] In the ductil shear zone of Berzosa Honrubia, active during the Hercynic second phase, finite strain ellipsoids have been calculated. Methods of Ramsay, Dunnet, and Fry have been used for this calculation. The results show a variation in the strain elipsoid shape through the shear zone trace. The central part h(!s strain ellipsoids with K1. Interpretation of those values is based on the variation in the orientation of the fault cartographic trace and tectonic transport direction. Ellipsoids with K1 are located where the trace and tectonic transport direction are parallel