Magnetism in graphene nanoislands

We study the magnetic properties of nanometer-sized graphene structures with triangular and hexagonal shapes terminated by zigzag edges. We discuss how the shape of the island, the imbalance in the number of atoms belonging to the two graphene sublattices, the existence of zero-energy states, and the total and local magnetic moment are intimately related. We consider electronic interactions both in a mean-field approximation of the one-orbital Hubbard model and with density functional calculations. Both descriptions yield values for the ground state total spin S consistent with Lieb’s theorem for bipartite lattices. Triangles have a finite S for all sizes whereas hexagons have S=0 and develop local moments above a critical size of ≈1.5  nm.

Los cinco testamentos de Francisco Xavier Balmis

El reciente hallazgo de los Protocolos Testamentarios Francisco Xavier Balmis (1753-1819), director de la Real Expedición Filantrópica de la Vacuna, constituye una nueva fuente documental para explorar su perfil biográfico. Balmis redactó un total de cinco testamentos que abarcan el periodo de 1803-1818 y coinciden con momentos cruciales de su vida. Su análisis ha permitido establecer interesantes observaciones que certifican su inseguridad personal antes de afrontar la expedición, su desamparo al ser despojado de sus bienes por adherirse a la causa monárquica frente a Napoleón, el consuelo al serle restituidos sus honores y hacienda o la entereza para afrontar sus últimos momentos. Revelan que Balmis supo hacer de la carrera profesional como cirujano militar un instrumento para alcanzar el prestigio social, y desmienten los supuestos sobre un final oscuro. El inventario de sus bienes ratifica su desahogada situación económica y su capacidad para gestionarlos. Las fuentes notariales se acreditan con este caso de Balmis, un funcionario de la Corona, como un ejemplo para el estudio de las oligarquías urbanas del Antiguo Régimen.

The European Resonance of Napoleon’s Defeat in Spain

The military event that sealed the defeat of Napoleon in Spain was the Battle of Vitoria on 21st June 1813, which saw the allied British, Spanish and Portuguese troops led by Wellington gain victory over Joseph Bonaparte's forces. It was the last great battle of what is known in Spain as the Guerra de la Independencia, in the United Kingdom as the Peninsular War and in France as the Guerre d'Espagne. While a sliver of Spanish territory remained under French control and the war itself went on for a few more months, it was the Battle of Vitoria that marked the end of Napoleon's rule on the Iberian Peninsula, as symbolised by the departure from Spain of Joseph Bonaparte, the monarch who had been imposed five years earlier to remove the Bourbons from the Spanish throne.