La caverna de José Saramago: imatge platònica versus metafísica

La caverna de José Saramago té com a referència indubtable la imatge de la caverna del llibre VII de la República de Plató, i, tanmateix, Saramago no és un escriptor idealista o metafísic. Aquest article mostra com, tot aprofitant l¿aplicabilitat amb què Plató dota la seva imatge, Saramago defensa la necessitat de saber rebre els missatges de la terra, de la matèria, de no esdevenir presoners en las cavernes daurades de la societat occidental, i d¿esdevenir lliures en la natura, phýsis, i no pas lluny o més enllà, metá, d¿ella.

La caverna de José Saramago: imagen platónica versus metafísica

La caverna de José Saramago tiene como referencia indudable la imagen de la caverna del libro VII de la República de Platón, y, sin embargo, Saramago no és un escritor idealista o metafísico. Este artículo muestra cómo, aprovechando la aplicabilidad con que Platón dotó a su imagen, Saramago defiende la necesidad de saber recibir los mensajes de la tierra, de la materia, de no convertirnos en prisioneros en las cavernas doradas de la sociedad occidental, y de ser libres en la naturaleza, phýsis, y no lejos o más allá, metá, de ella.

The Cave by José Saramago: Platonic image versus metaphysics

The cave by José Saramago has as a certain reference the image of the cave of book VII of Plato's Republic and, however, Saramago is not an idealistic or metaphysical writer. This article, taking advantage of the applicability with which Plato endowed his image, defends the urge to be open to the messages sent by the earth, by matter, the urge not to become prisoners in the golden caves of the Western society and, finally, the urge to find our freedom in Nature, phýsis, and not far or beyond, metá, it.

La caverna de José Saramago: imagen platónica versus metafísica

La caverna de José Saramago tiene como referencia indudable la imagen de la caverna del libro VII de la República de Platón, y, sin embargo, Saramago no és un escritor idealista o metafísico. Este artículo muestra cómo, aprovechando la aplicabilidad con que Platón dotó a su imagen, Saramago defiende la necesidad de saber recibir los mensajes de la tierra, de la materia, de no convertirnos en prisioneros en las cavernas doradas de la sociedad occidental, y de ser libres en la naturaleza, phýsis, y no lejos o más allá, metá, de ella.

Evaporation and coarsening dynamics with open boundaries

We present a study of the evaporation dynamics of a substance undergoing a coarsening process. The system is modeled by the Cahn-Hilliard equation with absorbing boundaries. We have found that the dynamics, although of a diffusive nature, is much slower than the usual one without coarsening. Analytical and simulation results are in reasonable agreement.

Competitive evaporation in arrays of droplets

We consider the evaporation of periodic arrays of initially equal droplets in two-dimensional systems with open (absorbing) boundaries. Our study is based on the numerical solution of the Cahn-Hilliard equation. We show that due to cooperative effects the droplets which are further from the boundary may evaporate earlier than those in the boundary¿s vicinity. The time evolution of the overall amount of matter in the system is also studied.

Particle dispersion in synthetic turbulent flows

We study particle dispersion advected by a synthetic turbulent flow from a Lagrangian perspective and focus on the two-particle and cluster dispersion by the flow. It has been recently reported that Richardson¿s law for the two-particle dispersion can stem from different dispersion mechanisms, and can be dominated by either diffusive or ballistic events. The nature of the Richardson dispersion depends on the parameters of our flow and is discussed in terms of the values of a persistence parameter expressing the relative importance of the two above-mentioned mechanisms. We support this analysis by studying the distribution of interparticle distances, the relative velocity correlation functions, as well as the relative trajectories.

Spatial correlations and cross sections of clusters in the A + B -> 0 reaction

We consider the distribution of cross sections of clusters and the density-density correlation functions for the A+B¿0 reaction. We solve the reaction-diffusion equations numerically for random initial distributions of reactants. When both reactant species have the same diffusion coefficients the distribution of cross sections and the correlation functions scale with the diffusion length and obey superuniversal laws (independent of dimension). For different diffusion coefficients the correlation functions still scale, but the scaling functions depend on the dimension and on the diffusion coefficients. Furthermore, we display explicitly the peculiarities of the cluster-size distribution in one dimension.