Ergodic solenoids and generalized currents

We introduce the concept of solenoid as an abstract laminated space. We do a thorough study of solenoids, leading to the notion of ergodic and uniquely ergodic solenoids. We define generalized currents associated with immersions of oriented solenoids with a transversal measure into smooth manifolds, generalizing Ruelle-Sullivan currents.Comment: 28 pages, 2 figures. Fully revised presentation of the paper. Accepted in Revista Matematica Complutense. The final publication is available at http://www.springerlink.co

Ergodic solenoidal homology: density of ergodic solenoids

A measured solenoid is a laminated space endowed with a tranversal measure invariant by holonomy, as defined in arXiv:0910.2836. A measured solenoid immersed in a smooth manifold produces a closed current (known as generalized Ruelle-Sullivan current). Uniquely ergodic solenoids are those for which there is a unique (up to scalars) transversal measure. By the results in arXiv:0910.2913, for any smooth manifold, any real homology class is represented by a uniquely ergodic solenoid. In this paper, we prove that the currents associated to uniquely ergodic solenoids are dense in the space of closed currents, therefore proving the abundance of such objects.Comment: 9 pages, 2 figure

Heating without heat: thermodynamics of passive energy filters between finite systems

Passive filters allowing the exchange of particles in a narrow band of energy are currently used in micro-refrigerators and energy transducers. In this letter, we analyze their thermal properties using linear irreversible thermodynamics and kinetic theory, and discuss a striking phenomenon: the possibility of increasing or decreasing simultaneously the temperatures of two systems without any supply of energy. This occurs when the filter induces a flow of particles whose energy is between the average energies of the two systems. Here we show that this selective transfer of particles does not need the action of any sort of Maxwell demon and can be carried out by passive filters without compromising the second law of thermodynamics. The phenomenon allows us to design cycles between two reservoirs at temperatures $T_1<T_2$ that are able to reach temperatures below $T_1$ or above $T_2$.Comment: 5 pages, 3 figure

Parámetros en la enseñanza de la traducción

Las clases universitarias de traducción son mejorables en su orientación al mercado, su fundamentación teórica, la ordenación de la progresión y las estrategias pedagógicas empleadas. Las asignaturas se podrían ordenar también por tipos textuales, condicionantes extralingüísticos y tareas profesionales. Se ofrecen parámetros orientativos para desarrollar un plan de estudios