Integrated random processes exhibiting long tails, finite moments, and power-law spectra

A dynamical model based on a continuous addition of colored shot noises is presented. The resulting process is colored and non-Gaussian. A general expression for the characteristic function of the process is obtained, which, after a scaling assumption, takes on a form that is the basis of the results derived in the rest of the paper. One of these is an expansion for the cumulants, which are all finite, subject to mild conditions on the functions defining the process. This is in contrast with the Lévy distribution¿which can be obtained from our model in certain limits¿which has no finite moments. The evaluation of the spectral density and the form of the probability density function in the tails of the distribution shows that the model exhibits a power-law spectrum and long tails in a natural way. A careful analysis of the characteristic function shows that it may be separated into a part representing a Lévy process together with another part representing the deviation of our model from the Lévy process. This

Simple holographic polarogram

A new technique capable of obtaining quantitative values of the rotation angle of the polarization vector by using holography is presented. This is a two-stage holographic process; during the recording stage a hologram of the object of interest is obtained. The reference beam is composed of two beams that form a small angle between them and keep their polarization states at right angles to each other. In the reconstruction stage of the hologram, two images from the hologram are obtained along two different angles. As a result of the interference between these two images, a set of parallel fringes is formed at the image plane. The fringe contrast on the reconstruction is related to the angle of the polarization vector of the light at each position on the image plane. Measurements of the rotation of the polarization angle of a fraction of a degree were obtained. The main application of this technique is in the study of transient phenomena, where single-shot measurements are the only means of obtaining reliable data.

La traducción del manga al español: Cuestiones lingüísticas, metodológicas y técnicas.

El trabajo trata la traducción del manga al castellano (cuestiones lingüísticas, metodológicas y técnicas): las características principales del japonés, el proceso de traducción, los métodos y las opciones de adaptación empleados por las editoriales españolas, y la compatibilidad de escritura en equipos españoles. Finalmente, incluye un ejemplo real de traducción.

Estudi de l'efectivitat del remat al primer toc dins la zona de finalització

L’objectiu principal d’aquest estudi ha estat comprovar quin nombre de contactes amb la pilota és més efectiu a l’hora d’executar l’acció del remat dins la zona de finalització. S’ha utilitzat la metodologia observacional, investigant en un context d’elit com són els partits realitzats per les quatre seleccions millor classificades a l’Eurocopa 2012. La investigació ha tingut en compte diferents variables del remat com el gol, el nombre de contactes amb la pilota abans del remat, l’orientació corporal del jugador que remata i la última acció abans que la pilota entri dins la zona de finalització per ser rematada. Els resultats obtinguts ens donen informació sobre com les seleccions de Portugal, Alemanya, Itàlia i Espanya finalitzaren les seves accions ofensives i permeten al lector fer-se una idea general de com hauria de realitzar-se un remat en la zona de finalització.

Anàlisi i quantificació de les accions i el temps de joc en l'hoquei sobre patins en equips de l'OK Lliga

Quantificar les variables temporal, les accions tècniques i els desplaçaments dels jugador al llarg de la competició proporciona una informació excel·lent per deduir les càrregues físiques i fisiològiques a les que estan sotmesos. Per aquest estudi es van visualitzar 4 partits de la Copa del Rei 2012. Es va enregistrà sistemàticament les dades en fulls de registre. Les principals dades analitzades van ser: temps total, temps real, temps de pausa, temps d’acció i relació entre el temps d’acció i el temps de pausa (densitat de treball). També es va analitzar: les incidències reglamentaries, les accions tècniques del jugador i els desplaçaments del jugador. El 45% de les accions es van produir entre 0 i 30s, i el promig d’interval de participació va ser 19:29s ±2:09. Més del 50% de les pauses es van produir entre 11s i 30s, i el promig d’interval de pausa va ser de 24:57s. Aquest va determinar que la densitat de treball era 1:1.3. Aproximadament el 70% de les incidències reglamentàries van ser faltes d’equip I tècniques. Van haver-hi 56 conduccions, 10 driblins, 12 remats, (3 xuts, 2 punxades/escopides, 5 remats de primeres i 2 arrossegades) i 80 passades. Finalment, en un partit el 42,23% dels desplaçaments van ser a baixa intensitat, el 27,02% van ser a intensitat mitjana i el 30,75% van ser a alta intensitat. A més a més, el 81,90% dels desplaçaments a alta intensitat van durar de 0s a 5s, el 54,56% a intensitat mitjana van durar de 6 a 10 s. I el 49,32% a intensitat baixa també van durar 6s a 10s. L’hoquei sobre patins és un esport en el que hi predominen els esforços intermitents a gran intensitat i de curta durada amb una important sol·licitació de la via anaeròbica alàctica. Analitzar la dimensió temporal, les accions tècniques i els desplaçaments dels jugador durant la competició permet estimar les exigències físiques i requeriments energètics, i aquest faciliten l’elaboració d’entrenaments més específics.

Análisis de la eficacia de los saques de esquina en la copa del mundo de fútbol 2010. Un intento de identificación de variables explicativas

In soccer, dead-ball moves are those in which the ball is returned to play from a stationary position following an interruption of play. The aim of this study was to analyse the effectiveness of one such dead-ball move, namely corner kicks, and to identify the key variables that determine the success of a shot or header following a corner, thereby enabling a model of successful corner kicks to be proposed. We recorded 554 corner kicks performed during the 2010 World Cup in South Africa and carried out a univariate, bivariate and multivariate analysis of the data. The results indicated that corners were of limited effectiveness in terms of the success of subsequent shots or headers. The analysis also revealed a series of variables that were significantly related to one another, and this enabled us to propose an explanatory model. Although this model had limited explanatory power, it nonetheless helps to understand the execution of corner kicks in practical terms.

Necrosis del tomate: "torrao "o "cribado"

Desde la primavera de 2001, viene presentándose en España una nueva enfermedad conocida con el nombre de "torrao" o "cribado". Los síntomas que habitualmente presentan las plantas afectadas son una necrosis en la parte basal del foliolo que evoluciona a cribado, en los peciolos aparecen manchas longitudinales en ocasiones endurecidas que llegan a curvar los foliolos, y los frutos manifiestan manchas necróticas, deformaciones que finalmente lo rajan, quedando comercialmente inviables. Muestreos realizados desde su aparición han determinado la mayor incidencia de la enfermedad en la zona de Murcia, seguido de Canarias y en menor proporción Almería, y Alicante. Los resultados de los análisis realizados a las 369 muestras recogidas determinan que el 67% de las muestras analizadas eran positivas a Pepino mosaic virus (PepMV). En los ensayos de transmisión, únicamente mediante el injerto, se consiguió reproducir los síntomas de la enfermedad en dos casos, en el resto las plantas inoculadas e injertadas únicamente mostraban síntomas típicos de PepMV y los análisis realizados confirmaron este aspecto. A la vista de los resultados obtenidos, se diseñó un nuevo método de diagnóstico que ha permitido la caracterización del 89% de las muestras analizadas como aislado Chileno 2 de PepMV, recientemente publicado en el Gen Bank (Accesión number: DQ000985). De acuerdo con lo expuesto podría tratarse de uno de los agentes implicados en el desarrollo del síndrome junto con otros factores aún por determinar

Modeling and manufacturability assessment of bistable quantum-dot cells

We have investigated the behavior of bistable cells made up of four quantum dots and occupied by two electrons, in the presence of realistic confinement potentials produced by depletion gates on top of a GaAs/AlGaAs heterostructure. Such a cell represents the basic building block for logic architectures based on the concept of quantum cellular automata (QCA) and of ground state computation, which have been proposed as an alternative to traditional transistor-based logic circuits. We have focused on the robustness of the operation of such cells with respect to asymmetries derived from fabrication tolerances. We have developed a two-dimensional model for the calculation of the electron density in a driven cell in response to the polarization state of a driver cell. Our method is based on the one-shot configuration-interaction technique, adapted from molecular chemistry. From the results of our simulations, we conclude that an implementation of QCA logic based on simple ¿hole arrays¿ is not feasible, because of the extreme sensitivity to fabrication tolerances. As an alternative, we propose cells defined by multiple gates, where geometrical asymmetries can be compensated for by adjusting the bias voltages. Even though not immediately applicable to the implementation of logic gates and not suitable for large scale integration, the proposed cell layout should allow an experimental demonstration of a chain of QCA cells.

Effects of the epitaxial layer thickness on the noise properties of Schottky barrier diodes

An analytical theory to describe the combined effects of the epitaxial layer thickness and the ohmic contact on the noise properties of Schottky barrier diodes is presented. The theory, which provides information on both the local and the global noise properties, takes into account the finite size of the epitaxial layer and the effects of the back ohmic contact, and applies to the whole range of applied bias. It is shown that by scaling down the epitaxial layer thickness, the current regime in which the noise temperature displays a shot-noise-like behavior increases at the cost of reducing the current range in which the thermal-noise-like behavior dominates. This improvement in noise temperature is limited by the effects of the ohmic contact, which appear for large currents. The theory is formulated on general trends, allowing its application to the noise analysis of other semiconductor devices operating under strongly inhomogeneous distributions of the electric field and charge concentrations.

Quantum-to-classical crossover in full counting statistics

The reduction of quantum scattering leads to the suppression of shot noise. In this Letter, we analyze the crossover from the quantum transport regime with universal shot noise to the classical regime where noise vanishes. By making use of the stochastic path integral approach, we find the statistics of transport and the transmission properties of a chaotic cavity as a function of a system parameter controlling the crossover. We identify three different scenarios of the crossover.

Effects of the epitaxial layer thickness on the noise properties of Schottky barrier diodes

An analytical theory to describe the combined effects of the epitaxial layer thickness and the ohmic contact on the noise properties of Schottky barrier diodes is presented. The theory, which provides information on both the local and the global noise properties, takes into account the finite size of the epitaxial layer and the effects of the back ohmic contact, and applies to the whole range of applied bias. It is shown that by scaling down the epitaxial layer thickness, the current regime in which the noise temperature displays a shot-noise-like behavior increases at the cost of reducing the current range in which the thermal-noise-like behavior dominates. This improvement in noise temperature is limited by the effects of the ohmic contact, which appear for large currents. The theory is formulated on general trends, allowing its application to the noise analysis of other semiconductor devices operating under strongly inhomogeneous distributions of the electric field and charge concentrations.