The structure of two new non-centrosymmetric phases of oxygen deficient bismuth manganite

The structure of two new phases in the bismuth manganite system are reported. The phases were determined by electron diffraction studies of two oxygen-deficient bulk samples. The first phase, a minority component of bulk BiMnO2.94 forms a n=2 Ruddlesden-Popper phase with space group Cmc21 . The second phase, from bulk BiMnO2.99 , is an orthorhombic structure with spacegroup Pmn21 and a unit cell approximately equal to 4 × √ 2 × 2 √ 2 times the parent perovskite cell. Importantly both phases are non-centrosymmetric and offer further potential for multiferroic studies.The authors would like to thank EPSRC for financial support for this work through grant EP/H017712

Notícia de dues tesis doctorals llegides en 2016 sobre Curial e Güelfa, els lectors i els contextos de lectura del segle xv

Notícia de dues tesis doctorals llegides en 2016 sobre Curial e Güelfa, els lectors i els contextos de lectura del segle x

Rebels on trial! The configuration of the enemy in the Comentarios of Álvar Núñez Cabeza de Vaca

En 1545, el segundo gobernador de la provincia del Río de la Plata, Álvar Núñez Cabeza de Vaca, regresa a España engrillado y con catorce pliegos de acusaciones a sus espaldas. Tras un largo pleito, que acaba con la absolución del imputado, Cabeza de Vaca decide contar su versión de los hechos publicando sus Comentarios (1555). Este texto supone el punto final de su defensa, pero también un juicio público que vuelve las tornas y sienta en el banquillo de los acusados a sus enemigos capitales. En este artículo se analizará cómo se configura la imagen de los rebeldes desde una perspectiva que se presenta como única portadora de los valores civilizadores en aquellas lejanas tierras carentes de todo orden conocido.En 1545, el segundo gobernador de la provincia del Río de la Plata, Álvar Núñez Cabeza de Vaca, regresa a España engrillado y con catorce pliegos de acusaciones a sus espaldas. Tras un largo pleito, que acaba con la absolución del imputado, Cabeza de Vaca decide contar su versión de los hechos publicando sus Comentarios (1555). Este texto supone el punto final de su defensa, pero también un juicio público que vuelve las tornas y sienta en el banquillo de los acusados a sus enemigos capitales. En este artículo se analizará cómo se configura la imagen de los rebeldes desde una perspectiva que se presenta como única portadora de los valores civilizadores en aquellas lejanas tierras carentes de todo orden conocido.In 1545, the second governor of the province of the Rio de la Plata, Álvar Núñez Cabeza de Vaca, returns in shackles to Spain with fourteen sheets full of accusations. After a long litigation that finally ends with the absolution of the accused, Cabeza de Vaca decides to share his version publishing his Comentarios (1555). This text is the final point of his defense, but also a public process that turn the tables on his foremost enemies sending them to the bench of the accused. This paper will analyze how the rebels' image is set from the point of view that represents the only owner of civilizing powers in those far away lawless lands

Cellular Automaton for Realistic Modelling of Landslides

A numerical model is developed for the simulation of debris flow in landslides over a complex three dimensional topography. The model is based on a lattice, in which debris can be transferred among nearest neighbors according to established empirical relationships for granular flows. The model is then validated by comparing a simulation with reported field data. Our model is in fact a realistic elaboration of simpler ``sandpile automata'', which have in recent years been studied as supposedly paradigmatic of ``self-organized criticality''. Statistics and scaling properties of the simulation are examined, and show that the model has an intermittent behavior.Comment: Revised version (gramatical and writing style cleanup mainly). Accepted for publication by Nonlinear Processes in Geophysics. 16 pages, 98Kb uuencoded compressed dvi file (that's the way life is easiest). Big (6Mb) postscript figures available upon request from [email protected] / [email protected]