Semiconductor cavity QED: Bandgap induced by vacuum fluctuations

We consider theoretically a semiconductor nanostructure embedded in one-dimensional microcavity and study the modification of its electron energy spectrum by the vacuum fluctuations of the electromagnetic field. To solve the problem, a non-perturbative diagrammatic approach based on the Green's function formalism is developed. It is shown that the interaction of the system with the vacuum fluctuations of the optical cavity opens gaps within the valence band of the semiconductor. The approach is verified for the case of large photon occupation numbers, proving the validity of the model by comparing to previous studies of the semiconductor system excited by a classical electromagnetic field. The developed theory is of general character and allows for unification of quantum and classical descriptions of the strong light-matter interaction in semiconductor structures

Axioms for consensus functions on the n-cube

An elementary general result is proved that allows for simple characterizations of well-known location/consensus functions (median, mean and center) on the n-cube. In addition, alternate new characterizations are given for the median and anti-median functions on the n-cube.Comment: 12 page

Tamizado para identificar frijoles adaptados a suelos acidos

General information on the nature of P, Al, and Mn and their interrelationship in the bean plant is presented. The methodology of screening to identify beans adapted to acid soils is indicated. This methodology includes site selection, determination of stress for Al, Mn, and P, simultaneous screening (on the basis of the former parameter), land preparation for planting and large-scale selection, modification of the screening methodology, and data collection and evaluation. Curves of response of some cv. to different P levels and to P as affected by N levels, yield curves, and lists of cv. efficient at low P and high Al and Mn levels are presented. (CIAT)Se presenta informacion general sobre la naturaleza del P, Al y Mn y su interrelacion en la planta del frijol. Se indica la metodologia del tamizado para identificar frijoles adaptados a suelos acidos. Esta metodologia incluye la seleccion del sitio, la determinacion del estres por Al, Mn y P, el tamizado simultaneo (con base en el parametro anterior), la preparacion de la tierra para siembra y la seleccion a gran escala, la modificacion a la metodologia de tamizado, y la recoleccion y evaluacion de datos. Se presentan curvas de respuesta de algunos cv. de frijol a diferentes niveles de P y a P afectado por niveles de N, curvas de rendimiento y listas de cv. eficientes a bajos niveles de P y altos niveles de Al y Mn. (CIAT

Resolution of inflammation: an integrated view

O.S. is supported by the NWO (VIDI project 91712303), theDFG (SO876/3-1, SO876/6-1, FOR809, SFB914 TPB08), theGerman-Israeli Foundation, and the Else Kro¨ner FreseniusStiftung. M.P. is supported by the Wellcome Trust (program086867/Z/08), the Arthritis Research UK, the British HeartFoundation (PG/09/060 and PG/11/48/28981) and the MedicalResearch Council

Linguagem/discurso como outra dimensão da perspectiva ctsa no ensino das ciências/geociências : ensaiando algumas relações possíveis

A dimensão da linguagem/discurso faz parte de estudos sobre ciência que relacionam ciência, tecnologia e sociedade, apontando para a necessidade da consideração tanto da materialidade da linguagem (sistemas significantes) quanto da sua relação com o contexto histórico-social de sua produção e com as relações entre os sujeitos. Esboçamos uma possível base teórico-metodológica para a construção de abordagens CTSA-discursivas, analisando a concepção de linguagem presente nesses estudos. Apresentamos três casos em que se aplicam elementos dessa base teórica envolvendo a análise de textos (escritos e audiovisuais) da mídia jornalística e de uma atividade em sala de aula envolvendo a linguagem cartográfica. Apontamos a construção discursiva dos sujeitos/atores, a não-neutralidade das produções textuais e o deslocamento para a noção de textualização

BCS pairing in fully repulsive fermion mixtures

We consider a mixture of two neutral cold Fermi gases with repulsive interactions. We show that in some region of the parameter space of the system the effective attraction between fermions of the same type can appear due to the exchange of collective excitations. This leads to the formation of BCS pairing in the case where bare inter-atomic interactions are repulsive

Analysis of columns with sheardeformation using finite element method and equivalent distributedloads

En este trabajo se aplica un procedimiento basado en el concepto de Acción Repartida Equivalente (ARE) al análisis, por el Método de Elementos Finitos (MEF) formulado en desplazamientos y solución nodal exacta, de pilares con deformación por cortante de acuerdo con la teoría de Timoshenko. Los resultados obtenidos con la metodología ARE-MEF, en los casos analizados, ponen de manifiesto que con un número muy reducido de elementos (uno y dos en los ejemplos desarrollados) se alcanza gran exactitud en desplazamientos, giros y esfuerzos. Sin embargo con otras metodologías formuladas en desplazamientos, como por ejemplo la de integración reducida, se requiere del orden de 40 elementos para alcanzar resultados similares. Asimismo en el presente trabajo, a partir del MEF con solución nodal exacta se determinan de una forma directa y sistemática las funciones de estabilidad y la carga de pandeo para el pilar de Timoshenko.This paper describes a procedure based on the concept of Equivalent Distributed Loads (EDL) applied to the Finite Elements Method (FEM) based on displacements and exact nodal solution of columns subject to shear deformation in accordance with the Timoshenko beam theory. The results obtained using this “EDL-FEM” methodology, in the cases studied, show that a high level of exactness in displacements, rotations as well as shear force and bending moment is obtained with a very small number of elements (one or two in the examples developed). Other methodologies based on displacements, such as reduced integration, require on the order of 40 elements to achieve similar results. The stability functions and buckling load for the Timoshenko beam are also determined in a direct and systematic way from the FEM with exact nodal solution.Peer Reviewe