A diagrammatic approach to study the information transfer in weakly non-linear channels

In a recent work we have introduced a novel approach to study the effect of weak non-linearities in the transfer function on the information transmitted by an analogue channel, by means of a perturbative diagrammatic expansion. We extend here the analysis to all orders in perturbation theory, which allows us to release any constraint concerning the magnitude of the expansion parameter and to establish the rules to calculate easily the contribution at any order. As an example we explicitly compute the information up to the second order in the non-linearity, in presence of random gaussian connectivities and in the limit when the output noise is not small. We analyze the first and second order contributions to the mutual information as a function of the non-linearity and of the number of output units. We believe that an extensive application of our method via the analysis of the different contributions at distinct orders might be able to fill a gap between well known analytical results obtained for linear channels and the non trivial treatments which are required to study highly non-linear channels.Comment: 17 pages, 3 figure

Beyond unobserved heterogeneity in computer wage premiums / Data on computer use in Germany, 1997 – 2001

Beyond unobserved heterogeneity in computer wage premiums: Most findings on the (non-)existence of a wage premium on computer use are biased because they are based on single-equation estimation of a wage equation. Controlling for fixed effects ignores the simultaneity problem. Through the introduction of a latent variable, “PC-feasibility”, we tackle the problem of simultaneity and account for unobserved heterogeneity. Due to the simultaneous nature of wage determination and computer use, the premium for computer use becomes dependent on person and job characteristics. Imposing testable restrictions on the reduced form enables us to identify the factors that determine wages and enhance computer use. The model is estimated using German data, 1997-2001 Data on computer use in Germany, 1997 – 2001: This paper describes the GSOEP data, 1997-2001, used in Muysken and Schim van der Loeff (2006). The data contain relevant information on individuals, with a focus on the computer use both at home and at work. The construction of the relevant data set for the period 1997 - 2001 is presented in section 2. A more detailed discussion of the data is presented in section 3 for the 1997 wave. Interesting observations are that most workers who use a computer at work started to use a computer at home simultaneously or later. Also the average number of years of employment for workers exceeds the period of the sample. Moreover there is a huge amount of inertia for computer use at work. This emphasises that fixed effects do not only control for unobserved individual characteristics, but also firm and job related characteristics. Finally, for rather homogenous groups of workers wages do not appear to vary systematically with computer use.Cross-Sectional Models, Wage Differentials by Skill

Sub‐Antarctic Magellanic Ornithology. The First Decade of Bird Studies at Omora Ethnobotanical Park, Cape Horn Biosphere Reserve

No abstract

Analytic treatment of geodesics in five-dimensional Myers-Perry space--times

We present the complete set of analytical solutions of the geodesic equation in the five-dimensional Myers-Perry space-time with equal rotation parameter in terms of the Weierstra{\ss}' elliptic and Weierstra{\ss}' zeta and sigma functions. We study the underlying polynomials in the polar and radial equations which depend on the parameters of the metric and conserved quantities of a test particle and characterize the motion by their zeros. We exemplify the efficiency of the analytical method on the orbits of test particles.Comment: 15 pages, 7 figures, to be published in PRD. Version with improved reference

Para la historia de la historiografía en México

1 archivo PDF (6 páginas). fhundequinquagintaReseña de la antología preparada por Evelia Trejo Estrada, "La historiografía del siglo XX en México" se parte de un concepto como producto académico y que la ocupa: la escritura de la historia –“el asunto de las diferentes maneras de presentar el pasado”–; es la piedra de toque que determina la elección de los textos que aquí se incluyen, 17 en total, clasificados en tres apartados específicos, Recuentos, Perspectivas teóricas y reflexiones. Cada uno con tiene escritos realizados por importantes autoridades de la materi

Particle motion in Horava-Lifshitz black hole space-times

We study the particle motion in the space-time of a Kehagias-Sfetsos (KS) black hole. This is a static spherically symmetric solution of a Horava-Lifshitz gravity model that reduces to General Relativity in the IR limit and deviates slightly from detailed balance. Taking the viewpoint that the model is essentially a (3+1)-dimensional modification of General Relativity we use the geodesic equation to determine the motion of massive and massless particles. We solve the geodesic equation exactly by using numerical techniques. We find that neither massless nor massive particles with non-vanishing angular momentum can reach the singularity at r=0. Next to bound and escape orbits that are also present in the Schwarzschild space-time we find that new types of orbits exist: manyworld bound orbits as well as two-world escape orbits. We also discuss observables such as the perihelion shift and the light deflection.Comment: 16 pages including 13 figures; minor changes, to match version accepted for publication in Phys. Rev.

Optimality Properties of Galerkin and Petrov-Galerkin Methods for Linear Matrix Equations

none2siGalerkin and Petrov–Galerkin methods are some of the most successful solution procedures in numerical analysis. Their popularity is mainly due to the optimality properties of their approximate solution. We show that these features carry over to the (Petrov-) Galerkin methods applied for the solution of linear matrix equations. Some novel considerations about the use of Galerkin and Petrov–Galerkin schemes in the numerical treatment of general linear matrix equations are expounded and the use of constrained minimization techniques in the Petrov–Galerkin framework is proposed.nonePalitta D.; Simoncini V.Palitta D.; Simoncini V

Distinguishing double neutron star from neutron star-black hole binary populations with gravitational wave observations

Gravitational waves from the merger of two neutron stars cannot be easily distinguished from those produced by a comparable-mass mixed binary in which one of the companions is a black hole. Low-mass black holes are interesting because they could form in the aftermath of the coalescence of two neutron stars, from the collapse of massive stars, from matter overdensities in the primordial Universe, or as the outcome of the interaction between neutron stars and dark matter. Gravitational waves carry the imprint of the internal composition of neutron stars via the so-called tidal deformability parameter, which depends on the stellar equation of state and is equal to zero for black holes. We present a new data analysis strategy powered by Bayesian inference and machine learning to identify mixed binaries, hence low-mass black holes, using the distribution of the tidal deformability parameter inferred from gravitational-wave observations.Comment: 13 pages, 6 figures - v2: matches the published version in Phys. Rev. D 102, 02302