Dynamics of a 1-D model for the emergence of the plasma edge shear flow layer with momentum conserving Reynolds stress

A one-dimensional version of the second-order transition model based on the sheared flow amplification by Reynolds stress and turbulence supression by shearing is presented. The model discussed in this paper includes a form of the Reynolds stress which explicitly conserves momentum. A linear stability analysis of the critical point is performed. Then, it is shown that the dynamics of weakly unstable states is determined by a reduced equation for the shear flow. In the case in which the flow damping term is diffusive, the stationary solutions are those of the real Ginzburg-Landau equation.Comment: 21 pages, 8 figure

Dual branes in topological sigma models over Lie groups. BF-theory and non-factorizable Lie bialgebras

We complete the study of the Poisson-Sigma model over Poisson-Lie groups. Firstly, we solve the models with targets $G$ and $G^*$ (the dual group of the Poisson-Lie group $G$) corresponding to a triangular $r$-matrix and show that the model over $G^*$ is always equivalent to BF-theory. Then, given an arbitrary $r$-matrix, we address the problem of finding D-branes preserving the duality between the models. We identify a broad class of dual branes which are subgroups of $G$ and $G^*$, but not necessarily Poisson-Lie subgroups. In particular, they are not coisotropic submanifolds in the general case and what is more, we show that by means of duality transformations one can go from coisotropic to non-coisotropic branes. This fact makes clear that non-coisotropic branes are natural boundary conditions for the Poisson-Sigma model.Comment: 24 pages; JHEP style; Final versio

Predict-prevent control method for perturbed excitable systems

We present a control method based on two steps: prediction and prevention. For prediction we use the anticipated synchronization scheme, considering unidirectional coupling between excitable systems in a master-slave configuration. The master is the perturbed system to be controlled, meanwhile the slave is an auxiliary system which is used to predict the master's behavior. We demonstrate theoretically and experimentally that an efficient control may be achieved.Comment: 4 pages, 5 figure

Measuring two-photon orbital angular momentum entanglement

We put forward an approach to estimate the amount of bipartite spatial entanglement of down-converted photon states correlated in orbital angular momentum and the magnitude of the transverse (radial) wave vectors. Both degrees of freedom are properly considered in our framework, which only requires azimuthal local linear optical transformations and mode selection analysis with two fiber detectors. The coincidence distributions predicted by our approach give an excellent fit to the distributions measured in a recent experiment aimed to show the very high-dimensional transverse entanglement of twin photons from a down-conversion source. Our estimate for the Schmidt number is substantially lower but still confirms the presence of high-dimensional entanglement.Comment: Extended paper of a published version in PRA, with some extra appendice

Thermal analysis applied to estimation of solidification kinetics of Al–Si aluminium alloys

Evaluation of solidification kinetics by thermal analysis is a useful tool for quality control of Al–Si melts before pouring provided it is rapid and highly reproducible. Series of thermal analysis records made with standard cups are presented that show good reproducibility. They are evaluated using a Newton’s like approach to get the instantaneous heat evolution and from it solidification kinetics. An alternative way of calculating the zero line is proposed which is validated by the fact that the latent heat of solidification thus evaluated is within 5% of the value calculated from thermodynamic data. Solidification kinetics was found highly reproducible provided appropriate experimental conditions were achieved: high enough casting temperature for the cup to heat up to the metal temperature well before solidification starts; and equal and homogeneous temperatures of the metal and of the cup at any time in the temperature range used for integration

Relationship between anxiety state, self-confidence and performance in basketball

El objetivo fue analizar la asociación entre intensidad y direccionalidad de la ansiedad y autoconfianza y el rendimiento competitivo en dos equipos de baloncesto de diferente sexo y nivel competitivo (G1: 1ª Nacional femenina; G2: Provincial masculino). Se administró el “Competitive State Anxiety Inventory 2” (CSAI-2) junto con una escala de direccionalidad 30 minutos antes de diferentes partidos de la temporada y se analizaron las grabaciones de los mismos, obteniéndose un índice de rendimiento individual (IR) de cada jugador. Los resultados revelaron la existencia de una relación en forma de “U” entre la intensidad de la ansiedad somática y el IR en el G1 (11,4%), y una relación lineal negativa entre la intensidad de la ansiedad cognitiva y el IR en el G2 (21,1%). No se ha encontrado relación alguna entre las percepciones direccionales de ansiedad y autoconfianza y el IR en ninguno de los dos grupos.The main purpose of this study was to analyze the association between the intensity and direction of anxiety and self-confidence and competitive performance on two basketball teams of different gender and competitive level (G1: 1st National Women, G2: Provincial male). We administered the Competitive State Anxiety Inventory 2 (CSAI-2) with a scale of directionality 30 minutes prior to every match of the season and analyzed recordings each one, resulting in a single performance index (RI) of each player. The results revealed the existence of a curvilinear-U relationship between the somatic anxiety intensity and RI in G1 (11,4%), and a negative linear relationship between the cognitive anxiety intensity and RI in G2 (21,1%). No relationship was found between directional perceptions of anxiety and self-confidence and IR in any both groups

Fractional generalization of Fick's law: a microscopic approach

In the study of transport in inhomogeneous systems it is common to construct transport equations invoking the inhomogeneous Fick law. The validity of this approach requires that at least two ingredients be present in the system. First, finite characteristic length and time scales associated to the dominant transport process must exist. Secondly, the transport mechanism must satisfy a microscopic symmetry: global reversibility. Global reversibility is often satisfied in nature. However, many complex systems exhibit a lack of finite characteristic scales. In this Letter we show how to construct a generalization of the inhomogeneous Fick law that does not require the existence of characteristic scales while still satisfying global reversibility.Comment: 4 pages. Published versio