Double Threefold Degeneracies for Active and Sterile Neutrinos

We explore the possibility that the 3 active (doublet) neutrinos have nearly degenerate masses which are split only by the usual seesaw mechanism from 3 sterile (singlet) neutrinos in the presence of a softly broken $A_4$ symmetry. We take the unconventional view that the sterile neutrinos may be light, i.e. less than 1 keV, and discuss some very interesting and novel phenomenology, including a connection between the LSND neutrino data and solar neutrino oscillations.Comment: 8 pages, no figur

Estudio comparativo entre dos protocolos anestésicos para la orquidectomía en el perro : sedación y bloqueo intratesticular frente a anestesia general

En este trabajo se utilizan dos protocolos anestésicos diferentes para la realización de la orquidectomía en el perro. Todos los pacientes reciben una mezcla intravenosa de medetomidina (10 μg/kg) y buprenorfina (20 μg/kg). En el primer grupo se realiza una infiltración intratesticular con lidocaína y en el segundo se administra bolos de propofol a efecto. Las cirugías son realizadas en todos los pacientes sin complicaciones. Comparativamente ambas técnicas se muestran apropiadas y seguras para este tipo de cirugía, pero la técnica local puede ofrecer varias ventajas, como son la mejor analgesia intraoperatoria, la recuperación más rápida del paciente y el menor coste económico de la misma. La aplicación de esta técnica local puede evitar el uso de anestesia general y hacer más sencillo el protocolo anestésico para este tipo de cirugías

Long-range correlations and trends in Colombian seismic time series

We study long-range correlations and trends in time series extracted from the data of seismic events occurred from 1973 to 2011 in a rectangular region that contains mainly all the continental part of Colombia. The long-range correlations are detected by the calculation of the Hurst exponents for the time series of interevent intervals, separation distances, depth differences and magnitude differences. By using a modification of the classical $R/S$ method that has been developed to detect short-range correlations in time series, we find the existence of persistence for all the time series considered except for magnitude differences. We find also, by using the $DFA$ until the third order, that the studied time series are not influenced by trends. Additionally, an analysis of the Hurst exponent as a function of the number of events in the time and the maximum window size is presented.Comment: 21 pages, 6 figures, 2 figures added, types corrected, accepted to be published in Physica

Study of the lepton flavor-violating Z′→τμZ'\to\tau\mu decay

The lepton flavor violating $Z^{\prime}\to\tau\mu$ decay is studied in the context of several extended models that predict the existence of the new gauge boson named $Z^\prime$. A calculation of the strength of the lepton flavor violating $Z^\prime\mu\tau$ coupling is presented by using the most general renormalizable Lagrangian that includes lepton flavor violation. We used the experimental value of the muon magnetic dipole moment to bound this coupling, from which the $\mathrm{Re}(\Omega_{L\mu\tau}\Omega^\ast_{R\mu\tau})$ parameter is constrained and it is found that $\mathrm{Re}(\Omega_{L\mu\tau}\Omega^\ast_{R\mu\tau})\sim 10^{-2}$ for a $Z^\prime$ boson mass of 2 TeV. Alongside, we employed the experimental restrictions over the $\tau\to\mu\gamma$ and $\tau\to\mu\mu^+\mu^-$ processes in the context of several models that predict the existence of the $Z^\prime$ gauge boson to bound the mentioned coupling. The most restrictive bounds come from the calculation of the three-body decay. For this case, it was found that the most restrictive result is provided by a vector-like coupling, denoted as $|\Omega_{\mu\tau}|^2$, for the $Z_\chi$ case, finding around $10^{-2}$ for a $Z^\prime$ boson mass of 2 TeV. We used this information to estimate the branching ratio for the $Z^\prime\to\tau\mu$ decay. According to the analyzed models the least optimistic result is provided by the Sequential $Z$ model, which is of the order of $10^{-2}$ for a $Z^\prime$ boson mass around 2 TeV.Comment: Revised versio

A new method for the solution of the Schrodinger equation

We present a new method for the solution of the Schrodinger equation applicable to problems of non-perturbative nature. The method works by identifying three different scales in the problem, which then are treated independently: An asymptotic scale, which depends uniquely on the form of the potential at large distances; an intermediate scale, still characterized by an exponential decay of the wave function and, finally, a short distance scale, in which the wave function is sizable. The key feature of our method is the introduction of an arbitrary parameter in the last two scales, which is then used to optimize a perturbative expansion in a suitable parameter. We apply the method to the quantum anharmonic oscillator and find excellent results.Comment: 4 pages, 4 figures, RevTex

Miniaturization of Planar Microwave Devices by Means of Complementary Spiral Resonators (CSRs): Design of Quadrature Phase Shifters

In this work, two compact quadrature phase shifters based on metamaterial transmission lines implemented by means of complementary spiral resonators (CSRs) have been designed, fabricated and measured. The structures consist on Y-junctions with output lines exhibiting 90º phase balance. The reported metamaterial-based devices present a size reduction of 64% and 77% as compared to the conventional one

Lupus eritematoso sistémico en un gato

Describimos el caso clínico de un gato macho de dos años de edad con un historial de gingivoestomatitis ulcerativa. Los análisis realizados revelan fallo renal con proteinuria, trombocitopenia e hipoalbuminemia. Tras el diagnóstico diferencial de glomerulonefropatía se procede a realizar un análisis de anticuerpos antinucleares, obteniéndose un resultado positivo. Se realiza el diagnóstico de lupus eritematoso sistémico basándonos en la presencia de cuatro de los criterios establecidos por la Asociación Americana de Reumatismo para el diagnóstico de lupus en humanos