On the bulk modulus of the cell model of charged macromolecules suspensions

We study theoretically the bulk modulus (inverse of the compressibility) of a suspension of charged objects (macro-ions), making use of a cell model to account for the finite density of macro-ions. The diffuse layer of charged micro-species around a macro-ion is described by a generic local density functional theory. Within this general framework, we obtain the condition for a positive bulk modulus, which is fulfilled by several proposals made in the literature and rules out the possibility of a critical point. We show that a sufficient condition for a positive compressibility also ensures that the same theory produces repulsive effective pair potentials

Counter-ion density profile around charged cylinders: the strong-coupling needle limit

Charged rod-like polymers are not able to bind all their neutralizing counter-ions: a fraction of them evaporates while the others are said to be condensed. We study here counter-ion condensation and its ramifications, both numerically by means of Monte Carlo simulations employing a previously introduced powerful logarithmic sampling of radial coordinates, and analytically, with special emphasis on the strong-coupling regime. We focus on the thin rod, or needle limit, that is naturally reached under strong coulombic couplings, where the typical inter-particle spacing $a'$ along the rod is much larger than its radius R. This regime is complementary and opposite to the simpler thick rod case where $a'\ll R$. We show that due account of counter-ion evaporation, a universal phenomenon in the sense that it occurs in the same clothing for both weakly and strongly coupled systems, allows to obtain excellent agreement between the numerical simulations and the strong-coupling calculations.Comment: 19 pages, 28 figure

Configurational and energy landscape in one-dimensional Coulomb systems

We study a one dimensional Coulomb system, where two charged colloids are neutralized by a collection of point counterions, with global neutrality. Temperature being given, two situations are addressed: the colloids are either kept at fixed positions (canonical ensemble), or the force acting on the colloids is fixed (isobaric-isothermal ensemble). The corresponding partition functions are worked out exactly, in view of determining which arrangement of counterions is optimal: how many counterions should be in the confined segment between the colloids? For the remaining ions outside, is there a left/right symmetry breakdown? We evidence a cascade of transitions, as system size is varied in the canonical treatment, or as pressure is increased in the isobaric formulation

The explosion in U.S. wealth inequality has been fuelled bystagnant wages, increasing debt, and a collapse in assetvalues for the middle classes

Income and economic equality have been on the rise in recent decades – but has this trend been fuelled only by increasing pay packets for the richest, or has wealth inequality risen as well? Emmanuel Saez and Gabriel Zucman find that over the past three decades the share of household wealth owned by the top 0.1 percent has increased from 7 to 22 percent. They write that the growing indebtedness of most Americans through mortgage and credit card obligations, combined with the collapse in the value of their assets during the Great Recession, and stagnant real wages have led to the erosion of the wealth share of the bottom 90 percent of families. They warn that without policies to reduce the concentration of wealth, such as estate taxes, within two decades the gains in wealth democratization which occurred in the New Deal and after World War II may well be lost

Semiotic Description of Music Structure: an Introduction to the Quaero/Metiss Structural Annotations

12 pagesInternational audienceInterest has been steadily growing in semantic audio and music information retrieval for the description of music structure, i.e., the global organization of music pieces in terms of large-scale structural units. This article presents a detailed methodology for the semiotic description of music structure, based on concepts and criteria which are formulated as generically as possible. We sum up the essential principles and practices developed during an annotation effort deployed by our research group (Metiss) on audio data in the context of the Quaero project, which has led to the public release of over 380 annotations of pop songs from three different data sets. The paper also includes a few case studies and a concise statistical overview of the annotated data

Supplementary material to the article: Estimating the structural segmentation of popular music pieces under regularity constraints

This document gathers descriptions of the structural segmentation systems considered in the IEEE/ACM TASLP paper by the same authors