Lattice effects and current reversal in superconducting ratchets

Competition between the vortex lattice and a lattice of asymmetric artificial defects is shown to play a crucial role in ratchet experiments in superconducting films. We present a novel and collective mechanism for current reversal based on a reconfiguration of the vortex lattice. In contrast to previous models of vortex current reversal, the mechanism is based on the global response of the vortex lattice to external forces.Comment: 12 pages, 7 figure

What Motivates Common Pool Resource Users? Experimental Evidence from the Field

This paper develops and tests several models of pure Nash strategies of individuals who extract from a common pool resource when they are motivated by a combination of self-interest and other motivations such as altruism, reciprocity, inequity aversion and conformism. We test whether an econometric summary of subjects’ strategies is consistent with one of these motivations using data from a series of common pool resource experiments conducted in three regions of Colombia. As expected, average extraction levels are less than that predicted by a model of pure self-interest, but are nevertheless sub-optimal. Moreover, we find that a model of conformism with monotonically increasing best response functions best describes average strategies. Our empirical results are inconsistent with models of altruism, reciprocity and inequity aversion.common pool resources, experiments, altruism, reciprocity, conformism

Sphaerodactylus fantasticus

Number of Pages: 8Integrative BiologyGeological Science

De cuervos y basiliscos: alegoría y corte en el Triunfo de las donas de Juan Rodríguez del Padrón

Juan Rodríguez del Padrón utiliza el marco narrativo del Triunfo de las donas, una obra de defensa de las mujeres, para, por medio de las cuatro lecturas clásicas de la alego-ría, educar a un público cortesano con el fin de obtener promoción palatina. Los animales simbólicos que utiliza Rodríguez del Padrón, el cuervo y el basilisco, tienen una múltiple lectura que sitúa la obra dentro del debate sobre la naturaleza de la mujer en la corte de Juan tí. Si el Basilisco (“regulus-i”) se refiere al rey, el “covarchon” responde no sólo al Corbaccio de Boccaccio sino también al Arcipreste de Talavera o Corbacho de Alfonso Martínez de Toledo, primer agraviador de las donas en la corte del rey poeta. Los animales del Triunfo de las donas nos presentan una especie de roman-á-clef en el que se discute la naturaleza femenina en la corte a la que pertenecía Rodríguez del Padrón. Juan Rodríguez del Padrón utilizes narrative frame of his Triunfo de las donas (Triumph of the Ladies), his defense of women, in order to educate his courtly audience through the four classical readings of allegory. He attempts to promote himself within the court. Of all symbolic animals, Padrón coses the crow and the basilisk for their potencial meaning. While the basilisk bring to mind its Latin etymology “regulus-i”, which ultimately links it with the king, the crow (covarchón) responds to Bocaccio’s Corvaccio and Alfonso Martínez de Toledo’s Arcipreste de Talavera o Corbacho which, being the work of one of the King’s chaplains, was the first offender of court ladies. The animals in Padrón’s Triunfo de las donas present a roman-à-clef which discusses female nature in Rodríguez del Padrón’s court

La ruda zampoña de Polifemo: autorrepresentación y parodia en la 'Fábula de Polifemo y Galatea' de Góngora

Como otros poetas barrocos, en su 'Fábula de Polifemo y Galatea' Góngora elige uno de sus personajes para representar su arte y para autorrepresentarse a sí mismo como poeta. La figura del monstruoso gigante Polifemo –símbolo irónico y desacralizador del arte de Góngora– contrasta con otras como Apolo u Orfeo –símbolo a su vez del arte de Lope–, a primera vista más apropiadas para el enaltecimiento personal. En concreto, este trabajo se centra en la historia cultural de la zampoña para mostrar lo apropiado de la elección de ésta por Góngora para su personaje Polifemo, a la vez que subraya lo irónico que resulta que el autor la afirme utilizar para cantar el poema. Mediante el instrumento, el poeta se identifica con el personaje: la monstruosidad de Polifemo, la exageración de su instrumento musical y la brutalidad de su voz son un espéculo, quizá invertido pero claramente divertido y paródico del proyecto poético del cordobés. Like other Baroque poets, Góngora in his 'Fábula de Polifemo y Galatea' chooses one of his characters to represent his art and to represent himself as a poet. The figure of the monstruous giant Polyphemus –the ironic and desacralizing symbol of Góngora’s art– enters in contrast with other figures, like Apollo and Orpheus– themselves symbols of the art of Lope– that at first glance might seem more appropriate for self-aggrandizement. This paper focuses specifically on the cultural history of the pan flute to demonstrate the appropriateness of Góngora’s choice of this instrument for his character Polyphemus, at the same time highlighting the irony of the author’s own affirmation that he uses the pan flute to sing his poem. By means of this instrument, the poet identifies himself with the character: the monstrosity of Polyphemus, the exaggeration of his musical instrument, and the brutality of his voice become a mirror –perhaps an inverted, although ultimately amusing and parodical one– of the poetic project of the Cordoban