Radiative two-pion decay of the tau lepton

We consider the bremsstrahlung and model-dependent contributions to the radiative decay $\tau^- \to \pi^-\pi^0\nu_{\tau}\gamma$ in the context of a meson dominance model. We focus on several observables related to this decay, including the branching ratio and the photon and di-pion spectra. Particular attention is paid to the sensitivity of different observables upon the effects of model-dependent contributions and of the magnetic dipole moment of the $\rho^-(770)$ vector meson. Important numerical differences are found with respect to results obtained in the framework of chiral perturbation theory.Comment: 14 pages, 8 figures, submitted for publicatio

La figura del facilitador en la investigación policial y judicial con víctimas con discapacidad intelectual = The figure of the helper advisor in police and judicial research involving persons with intellectual disabilities

En el presente trabajo analizamos algunos factores que inciden en la especial vulnerabilidad de las personas con Discapacidad Intelectual (DI) a ser víctimas de abusos y a sufrir una revictimización tras los mismos. De ellos destacamos la escasa adecuación de las entrevistas policiales y judiciales a sus características, y los sesgos en los juicios de credibilidad de los testimonios de las personas con DI. Frente a éstos, la Unidad de Atención a Víctimas con Discapacidad Intelectual (UAVDI) propone la introducción de la figura del facilitador en todo proceso policial y judicial con víctimas con DI. Presentamos aquellas investigaciones realizadas en la UAVDI que apoyan la instauración de adaptaciones en las ruedas de reconocimiento y en las entrevistas de obtención del testimonio de personas con DI. La introducción de las mismas es uno de los objetivos del facilitador, cuyo trabajo queda ilustrado en el análisis de un caso de una víctima de abuso sexual con DI. [ABSTRACT] In this paper we analyse some of the factors that affect the vulnerability of people with intellectual disability (ID) to be victims of abuse. The lack of adaptation of police and judicial interviews and the biases in the credibility judgments given to the testimony of people with ID were analysed. The Victim Support Unit for People with Intellectual Disability proposes as a solution the figure of the “helper advisor” in the police and judicial procedures. We will present the investigations made in our Care Unit that support the inclusion of adaptations in the line-up identifications and the interviews to obtain the testimony of the victim with ID. Application of these adaptations is one of the objectives of the “helper-advisor”, whose work will be illustrated by the analysis of a case of sexual abuse to a person with ID

The Muon Anomalous Magnetic Moment - Significance of the New Measurement

Theoretical calculations of the hadronic contribution to the muon anomalous magnetic moment utilize experimental data from e+e- annhilation and tau decay. The data provide input to a dispersion relation. I contend that it is not possible to put error bounds on the dispersion-relation calculation absent proof - not presently available - that the amplitudes in question are polynomially bounded. Examples are provided. Additional pertinent references have been added to an earlier version of this posting.Comment: 9 pages,LaTeX, 2 figure

Non-volatility of ferroelectric SBT thin fims, at 75ºC

[ES] El estudio de la no volatilidad de una memoria FeRAM de tantalato de bismuto y estroncio, SrBi2Ta2O9 (SBT) en condiciones reales de uso, requiere la caracterización ferroeléctrica del material en forma de lámina delgada a temperaturas por encima del ambiente. Para ello se han depositado láminas de SBT mediante un método sol-gel, sobre substratos de Pt/TiO2/SiO2/Si(100), seleccionándose condensadores de área 5.10-4 cm-2. Basándonos en las medidas de la variación de la polarización con el tiempo (retención) realizadas a temperatura ambiente y a 75ºC, analizamos la viabilidad del material como una FeRAM en condiciones reales de uso.[EN] The study of the non-volatility of Strontium bismuth tantalate SrBi2Ta2O9 (SBT) FeRAM memory, at real operating conditions, requires the ferroelectric characterisation of the material, as a thin film, above the room temperature.As a result, it has been deposited SBT films by the sol-gel method, onto Pt/TiO2/SiO2/Si (100) substrates, using capacitors of 5 x 10–4 cm-2 .In this work, we analysed the viability of this material as a FeRAM memory in real operating conditions, as a result of the variation of the polarisation measurements with time (retention), performed at room temperature and 75ºC.Este trabajo ha sido realizado con el apoyo del proyecto de la CICYT MAT98-1068.Peer reviewe

From two-dimensional to three-dimensional turbulence through two-dimensional three-component flows

The relevance of two-dimensional three-components (2D3C) flows goes well beyond their occurrence in nature, and a deeper understanding of their dynamics might be also helpful in order to shed further light on the dynamics of pure two-dimenional (2D) or three-dimensional (3D) flows and vice versa. The purpose of the present paper is to make a step in this direction through a combination of numerical and analytical work. The analytical part is mainly concerned with the behavior of 2D3C flows in isolation and the connection between the geometry of the nonlinear interactions and the resulting energy transfer directions. Special emphasis is given to the role of helicity. We show that a generic 2D3C flow can be described by two stream functions corresponding to the two helical sectors of the velocity field. The projection onto one helical sector (homochiral flow) leads to a full 3D constraint and to the inviscid conservation of the total (three dimensional) enstrophy and hence to an inverse cascade of the kinetic energy of the third component also. The coupling between several 2D3C flows is studied through a set of suitably designed direct numerical simulations (DNS), where we also explore the transition between 2D and fully 3D turbulence. In particular, we find that the coupling of three 2D3C flows on mutually orthogonal planes subject to small-scale forcing leads to stationary 3D out-of-equilibrium dynamics at the energy containing scales. The transition between 2D and 3D turbulence is then explored through adding a percentage of fully 3D Fourier modes in the volume.Comment: postprint versio

Feasibility of (Pb, Ca)TiO3 thin films deposited on Pt/TiO2/SiO2/Si(100) for switching applications

[ES] Se han depositado láminas delgadas de (Pb,Ca)TiO3 sobre substratos de Pt/TiO2/SiO2/Si(100) por centrifugación, partiendo de soluciones sintetizadas por sol -gel. La concentración de las soluciones y el contenido de PbO se seleccionaron para minimizar las tensiones de las láminas cristalizadas y obtener la adecuada estequiometria. La cristalización mediante un calentamiento rápido (RTP), conduce a láminas con orientaciones preferentes [001]/[001], reducida capa interfacial ferroeléctrico-Pt y composición deseada. Los parámetros ferroeléctricos obtenidos muestran una mejora de las propiedades. Estas láminas presentan una fatiga y envejecimiento mucho más moderados que otros materiales alternativos depositados sobre substratos iguales, lo que permite considerar al método descrito como muy valioso para conseguir materiales susceptibles de emplear en aplicaciones de conmutación.[EN] (Pb,Ca)TiO3 ferroelectric thin films have been spin-coated on Pt/TiO2/SiO2/Si(100) substrates from sol-gel synthesized solutions. Selecting the solution concentrations and the excess of PbO content, stoichiometric composicion with reduced strains are obtained. Crystallization process by rapid thermal treatment (RTP) promote preferred orientations [001]/[100] resulting a thiner ferroelectric-platinum interface layer, which causes the improvement of fatigue and retain behaviour, despite the use of platinum electrodes. These experimental finds let to cosider the described methode of processing very convenient to prepare thin films of this composition to use on switching applications such as non volatil RAM memories.Peer reviewe

Hadronic Vacuum Polarization and the Lamb Shift

Recent improvements in the determination of the running of the fine-structure constant also allow an update of the hadronic vacuum-polarization contribution to the Lamb shift. We find a shift of -3.40(7) kHz to the 1S level of hydrogen. We also comment on the contribution of this effect to the determination by elastic electron scattering of the r.m.s. radii of nuclei.Comment: 7 pages, latex, 1 figure -- Submitted to Phys. Rev. A -- epsfig.sty require

Momentum Project: buscando el equilibrio Entre la Creación de Valor Económico y valor social

[Translated abstract] This paper analyzes an in-depth case analysis on impact investment in Spain. Momentum Project is an initiative to support social entrepreneurs in their path to growth. The goal is to increase the social return and to help the social enterprises to reach their long-term sustainability. At the beginning, Momentum started as an “accelerator” for social entrepreneurs; however, an impact investment vehicle is created to support the financial needs of the growth plan. The characteristics of the investment vehicle are compared to those of the philanthropic venture capital as studied in the academic literature. [Original abstract: El presente artículo analiza un caso de estudio sobre inversión de impacto en España. Momentum Project es una iniciativa que surge para apoyar a los emprendedores sociales a escalar su empresa, con el objeto de incrementar el retorno social y conseguir la sostenibilidad a largo plazo de las empresas. En un primer momento se plantea como una “aceleradora” para emprendedores sociales, sin embargo, se acaba implementando un vehículo de inversión de impacto para poder dar apoyo a las necesidades financieras del plan de crecimiento. Las características del vehículo de Momentum son comparadas con las del capital riesgo filantrópico de acuerdo a la literatura académica.

Hadron Production via e+e- Collisions with Initial State Radiation

A novel method of studying e+e- annihilation into hadrons using initial state radiation at e+e- colliders is described. After brief history of the method, its theoretical foundations are considered. Numerous experiments in which exclusive cross sections of e+e- annihilation into hadrons below the center-of-mass energy of 5 GeV have been measured are presented. Some applications of the results obtained to fundamental tests of the Standard Model are listed.Comment: 50 pages, 88 figures, accepted for publication in Rev. Mod. Phy