Spin and charge optical conductivities in spin-orbit coupled systems

We study the frequency dependent spin- and charge- conductivity tensors of a two-dimensional electron gas (2DEG) with Rashba and Dresselhaus spin-orbit interaction. We show that the angular anisotropy of the spin-splitting energy induced by the interplay between the Rashba and Dresselhaus couplings gives rise to a characteristic spectral behavior of the spin and charge response which is significantly different from that of pure Rashba or Dresselhaus case. Such new spectral structures open the possibility for control of the optical response by applying an external bias and/or by adjusting the light frequency. In addition, it is shown that the relative strength of the spin-orbit coupling parameters can be obtained through optical probing.Comment: 13 pages, 4 figures. Revised versio

Survey and Assessment of Laws on the Informal Sector

This study classifies the laws affecting the informal sector and assesses the extent of the empowerment of the sector based on the provisions in the laws that allow for organization, decision making mechanisms and transfer of power from the traditional center to another. Results indicate that, to some extent, four groups within the sector are accorded empowerment through Philippine laws: the agricultural sector, small and medium enterprises, industrial home workers and cooperatives. These groups are allowed to form organizations and to participate in decision making bodies. Decision making is accorded to certain groups among informal sector, which, in some cases, comprise the majority members in decision making bodies. Nowhere among the laws is a shift of power provided from the traditional or government decision makers to the informal sector. However, certain groups within the IS have participated in the institution of some policies and the realization of programs for their own advantage.informal financial sectors, small and medium enterprises

Survey and Assessment of Laws on the Informal Sector

This study classifies the laws affecting the informal sector and assesses the extent of the empowerment of the sector based on the provisions in the laws that allow for organization, decision making mechanisms and transfer of power from the traditional center to another. Results indicate that, to some extent, four groups within the sector are accorded empowerment through Philippine laws: the agricultural sector, small and medium enterprises, industrial home workers and cooperatives. These groups are allowed to form organizations and to participate in decision making bodies. Decision making is accorded to certain groups among informal sector, which, in some cases, comprise the majority members in decision making bodies. Nowhere among the laws is a shift of power provided from the traditional or government decision makers to the informal sector. However, certain groups within the IS have participated in the institution of some policies and the realization of programs for their own advantage.informal financial sectors, small and medium enterprises

Buenos Aires que surge. Pío Collivadino y la construcción del paisaje urbano

Desde fines del siglo XIX, Buenos Aires estaba en construcción. El progreso logrado hacia 1910, se mezclaba con signos del pasado: modernos rascacielos coexistían con los viejos edificios coloniales; se amasaban fortunas, mientras miles de inmigrantes luchaban para sobrevivir. En este periodo de grandes esperanzas, se produjeron imágenes del paisaje de Buenos Aires que continúan vigentes en el imaginario de la ciudad, muchas de las cuales fueron plasmadas por Pío Collivadino (Buenos Aires, 1869-1945). Habiendo estudiado en Roma por diecisiete años, sus pinturas tenían muchas similitudes formales con la pintura italiana del periodo. Sin embargo, sus imágenes urbanas se convirtieron en una opción en la búsqueda del paisaje nacional. Su enfoque muestra la tensión entre la Academia –institución que dirigió por 30 años-, y las influencias románticas y vanguardistas. A partir del análisis de su colección personal, se indagará en los diálogos y puntos de cruce entre sus numerosas fuentes (revistas, postales, fotografías), sumadas a sus bocetos tomados a plein air; lo que resulta en una excepcional visión de Buenos Aires que no ha sido aún analizada en profundidad, que resultará fundamental para entender el rol de sus pinturas en la construcción del imaginario de la ciudad moderna

Plasmon-enhanced second harmonic generation in semiconductor quantum dots close to metal nanoparticles

We report the enhancement of the optical second harmonic signal in non-centrosymmetric semiconductor CdS quantum dots, when they are placed in close contact with isolated silver nanoparticles. The intensity enhancement is about 1000. We also show that the enhancement increases when the incoming laser frequency $\omega$ is tuned toward the spectral position of the silver plasmon at $2\omega$, proving that the silver nanoparticle modifies the nonlinear emission.Comment: 5 pages, 5 figure

Special Issue on Spin Statistics

A workshop dedicated to spin statistics—"SpinStat2008"—was held at the end of October 2008 at the Stazione Marittima Conference Center in Trieste, Italy: it was meant to focus especially on experimental and theoretical aspects of the spin-statistics connection and of related symmetries (in particular the CPT and the Lorentz symmetries). The workshop was quite successful and everybody there felt that there should be a follow-up, and that the many interesting contributions and ideas presented there should be put in paper form. After some thinking we decided that the best format would be a series of refereed papers in a topical issue of an outstanding journal, open to all contributors, rather than the usual volume of conference papers restricted to participants. The Editors of Foundations of Physics kindly accepted to host this topical issue, and the ensuing call for papers drew a respectable flow of interesting and novel ideas, and some very appealing review papers. The comments that follow have bee

Hydrolysis of lactose: estimation of kinetic parameters using Artificial Neural Networks

The analysis of any kinetic process involves the development of a mathematical model with predictive purposes. Generally, those models have characteristic parameters that should be estimated experimentally. A typical example is Michaelis-Menten model for enzymatic hydrolysis. Even though conventional kinetic models are very useful, they are only valid under certain experimental conditions. Besides, frequently large standard errors of estimated parameters are found due to the error of experimental determinations and/or insufficient number of assays. In this work, we developed an artificial neural network (ANN) to predict the performance of enzyme reactors at various operational conditions. The net was trained with experimental data obtained under different hydrolysis conditions of lactose solutions or cheese whey and different initial concentrations of enzymes or substrates. In all the experiments, commercial beta-galactosidase either free or immobilized in a chitosan support was used. The neural network developed in this study had an average absolute relative error of less than 5% even using few experimental data, which suggests that this tool provides an accurate prediction method for lactose hydrolysisFil: Cuellas, Anahí V.. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Área Ingeniería en Alimentos; ArgentinaFil: Oddone, Sebastián. Universidad Argentina de la Empresa. Facultad de Ingeniería y Ciencias Exactas; ArgentinaFil: Mammarella, Enrique José. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Desarrollo Tecnológico Para la Industria Química (i); ArgentinaFil: Rubiolo, Amelia Catalina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Desarrollo Tecnológico Para la Industria Química (i); Argentin

Correlations between Complexity and Entanglement in a One-Dimensional XY Model

Many people believe that the study of complex quantum systems may be simplified by first analyzing the static and dynamic entanglement present in those systems [Phys. Rev. A 66 (2002) 032110]. In this paper, we attempt to complement such notion by adding an order–disorder quantifier called statistical complexity and studying how it is correlated with the degree of entanglement as measured by the concurrence quantifier. We perform such an analysis with reference to a representative system chosen from condensed matter theory, the so-called XY model. Some interesting insight is obtained as the concurrence and the complexity become correlated in an unexpected fashion.Fil: Apel, V. M.. Universidad Católica del Norte; ChileFil: Mundarain, Douglas. Universidad Católica del Norte; ChileFil: Pennini, Flavia Catalina. Universidad Católica del Norte; Chile. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Confluencia; ArgentinaFil: Plastino, Ángel Luis. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentin

Encarcelamiento materno y problemas de comportamiento en niños, niñas y jóvenes en Chile

La tasa de encarcelamiento ha aumentado significativamente en Chile en las últimas décadas, siendo este aumento particularmente pronunciado en el caso de la población penal femenina. En una sociedad patriarcal donde la crianza recae principalmente en las mujeres, esto genera consecuencias para ellas y sus hijos/as. Este artículo explora en qué medida las características de los/as niños/as, del contexto donde quedan y de la condena de la madre se relacionan con más conductas problemáticas. Con una muestra representativa de mujeres privadas de libertad de Santiago de Chile, y a través de regresiones logísticas, se evidencia que los/as niños/as de mayor edad, que vivían con su madre antes del encarcelamiento y reportan problemas con la persona que queda a cargo de cuidarles fuera de la cárcel tienen mayores probabilidades de presentar conductas problemáticas. Estos resultados son robustos incluso cuando se controla por el consumo de sustancias y la reincidencia previa de la madre