FRW in cosmological self-creation theory: Hamiltonian approach

We use the Brans-Dicke theory from the framework of General Relativity (Einstein frame), but now the total energy momentum tensor fulfills the following condition $\rm[\frac{1}{\phi}(8\pi T^{\mu \nu (M)}+T^{\mu\nu (\phi)})]_{;\nu}=0$. We take as a first model the flat FRW metric in the Hamilton-Jacobi scheme and we present the Lagrange-Charpit approach in order to find classical solutions. In the quantum scheme, once we determine the characteristic surfaces, the quantum solution is obtained. These two classes of solutions are found for all values of the barotropic parameter $\gamma$.Comment: 9 pages, latex2e. arXiv admin note: substantial text overlap with arXiv:1206.541

The importance of being mature: the effect of demographic maturation on global per-capita GDP

Given that savings behaviour and worker productivity have strong life-cycle components and given that demographic profiles vary across countries, population age structure should be linked to differences in levels of economic development. In this paper we measure the economic importance of age structure variation for the global economy. We find that even after adjusting for country-specific effects, demographic maturation has been associated with nearly half of the evolution of global per-capita GDP since 1960. We also find that age structure differences can account for just over half of the variation in worldwide per capita GDP (i.e. the lack of sigma convergence) observed since 1960. Taken as a whole, these results complement recent theoretical and empirical work on the importance of population size and economic development and reinforce empirical work linking mature demographic age structures with faster cross-country economic growth rates. JEL Classification: J13, J22, J24, O11, O40age structure, cross-country growth, life cycle savings model

Argumentos para una Epistemología del Dato Visual

En este trabajo argumento que no hay consenso epistemológico ni metodológico en las disciplinas que colaboran en el análisis de los datos visuales para la investigación social. Propongo que una alternativa epistemológica en este campo puede fundase bajo una perspectiva constructivista que retoma las problemáticas de la intersubjetividad e intencionalidad en la construcción de los datos. Por otro lado elaboro como un ejercicio preliminar una categorización de los tipos de análisis visual con base en su grado de complejidad analítica

The self organizing map of neighbour stars and its kinematical interpretation

The Self-Organizing Map (SOM) is a neural network algorithm that has the special property ofcreating spatially organized tepresetüatioes of various features of input signals. The resulting maps resemble realneural structures found in the cortices of developed animal brains.: Also, the SOM. has been successful in various pattern recognition tasks involving noisy signals, as for instance, speech recognition and for this reason we are studying its application to some astronomical problems. In this paper w~ present the 2-D mapping and subsequerít study of one local sample of 12000 stars using SOM. The available attributes are 14: 3-D position and velocitiesvphotometric indexes, spectral type and luminosity class. The possible location of halo, thick disk and thin disk stars is discussed. Their kinematical properties are also compared using the velocity distribution moments up to order four.Peer ReviewedPostprint (published version

Economía de esfuerzos para la presencia de las bibliotecas en las redes sociales

The proliferation of social networking tools brings new challenges to make visible and effective library services in the virtual fields. One difficulty stems from not less than the multiplicity of existing channels, its volatility and constant renewal, which may demand a volume of exertion for the real capacity of the library and end returns it can get. Our experience is going through the selection of tools to use in terms of the stability, popularity and friendliness (Web, Facebook, Twitter, Netvibes ...), and interconnection of all or any of its elements, so that the maintenance Information and services offered by these channels does not distract our human resources from other tasks that are still badly needed

Nonlinear gyrotropic vortex dynamics in ferromagnetic dots

The quasistationary and transient (nanosecond) regimes of nonlinear vortex dynamics in a soft magnetic dot driven by an oscillating external field are studied. We derive a nonlinear dynamical system of equations for the vortex core position and phase, assuming that the main source of nonlinearity comes from the magnetostatic energy. In the stationary regime, we demonstrate the occurrence of a fold-over bifurcation and calculate analytically the resonant nonlinear vortex frequencies as a function of the amplitude and frequency of the applied driving field. In the transient regime, we show that the vortex core dynamics are described by an oscillating trajectory radius. The resulting dynamics contain multiple frequencies with amplitude decaying in time. Finally, we evaluate the ranges of the system parameters leading to a vortex core instability (core polarization reversal)