Neutrino mixing in a left-right model

We study the mixing among different generations of massive neutrino fields in a $SU(2)_L \times SU(2)_R \times U(1)_Y$ gauge theory which includes Majorana and Dirac mass terms in the Yukawa sector. Parity can be spontaneously broken at a scale $v_R\simeq 10^3-10^4$ GeV. We discuss about possible candidates for the Yukawa coupling matrices and we found that the model can accommodate a consistent pattern for neutral fermion masses as well as neutrino oscillations. The left and right sectors can be connected by a new neutral current.Comment: 9 page

Genetic diversity of maize (Zea mays L. ssp. mays) in communities of the western highlands of Guatemala: geographical patterns and processes.

This study concerns spatial genetic patterning, seed flow and the impact of modern varieties in maize populations in Chimaltenango, Guatemala. It uses a collection of 79 maize seed samples from farmers in the area and five samples derived from modern varieties. Bulked SSR markers employed with bulked samples (ten plants) were used. Genetic distances between populations based on these SSR data were used as a measure of co-ancestry. The study describes the genetic variation in space, assesses the association of maize diversity with spatial and environmental descriptors and quantitative traits, and provides a test of the impact of improved varieties. Maize diversity showed significant isolation-by-distance locally, but not regionally. This was interpreted as evidence for a difference between local and regional mechanisms of seed exchange; regional exchange is more related to innovation. There was also a significant association with altitude and ear/grain characteristics (related to racial classifications). Also, consistent evidence for the influence of modern varieties of maize was found, although its impact was limited spatially. It is argued that the spatial distributions of maize diversity are important to consider for germplasm collection, but should be seen as a recent outcome of dynamic processes

Approximate solutions for the single soliton in a Skyrmion-type model with a dilaton scalar field

We consider the analytical properties of the single-soliton solution in a Skyrmion-type Lagrangian that incorporates the scaling properties of quantum chromodynamics (QCD) through the coupling of the chiral field to a scalar field interpreted as a bound state of gluons. The model was proposed in previous works to describe the Goldstone pions in a dense medium, being also useful for studying the properties of nuclear matter and the in-medium properties of mesons and nucleons. Guided by an asymptotic analysis of the Euler-Lagrange equations, we propose approximate analytical representations for the single soliton solution in terms of rational approximants exponentially localized. Following the Pad\'e method, we construct a sequence of approximants from the exact power series solutions near the origin. We find that the convergence of the approximate representations to the numerical solutions is considerably improved by taking the expansion coefficients as free parameters and then minimizing the mass of the Skyrmion using our ans\"atze for the fields. We also perform an analysis of convergence by computation of physical quantities showing that the proposed analytical representations are very useful useful for phenomenological calculations.Comment: 13 pages, 3 eps figures, version to be published in Phys.Rev.

Valoração econômica da perda de solo na cultura de cana-de-açúcar colhida crua e queimada no município de Campos dos Goytacazes.

Este trabalho foi realizado no Município de Campos dos Goytacazes, RJ e teve como objetivo valorar economicamente as perdas de solo em relação aos nutrientes perdidos na cultura de cana-de-açúcar sob dois sistemas distintos de colheita, cana-de-açúcar crua e queimada em áreas de baixada e de tabuleiro. Utilizou-se a Universal Soil Loss Equation ? USLE e o método do custo de reposição de nutrientes, para realizar a estimação econômica das perdas de solo. Os resultados mostram que a taxa de perda de solo da cana-de-açúcar queimada foi quatro vezes maior quando comparada à taxa para cana-de-açúcar colhida crua para ambas as áreas estudadas. O custo de reposição dos nutrientes perdidos no cultivo da cana-de-açúcar sob sistema de colheita com queima prévia apresentou um valor de R$10,53 por hectare, já o custo para área com cana crua foi de R$ 2,61 por hectare em área de baixada e de R$43,59 por hectare para cana queimada e R$ 10,89 para cana crua em tabuleiro. Dessa forma, o sistema de manejo da colheita da cana crua contribui ambientalmente e economicamente para a preservação da fertilidade do solo

Malware Analysis and Detection on Android: The Big Challenge

The popularization of the use of mobile devices, such as smartphones and tablets, has accelerated in recent years, as these devices have experienced a reduction in cost together with an increase in functionality and services availability. In this context, due to its openness and free availability, Android operating system (OS) has become not only a major stakeholder in the market of mobile devices but has also become an attractive target for cybercriminals. In this chapter, we advocate to present some current trends and results in the Android malware analysis and detection research area. We start by briefly describing the Android’s security model, followed by a discussion of the static and dynamic malware analysis techniques in order to provide a general view of the analysis and detection process to the reader. After that, a description of a particular set of software developments, which exemplify some of the discussed techniques, is presented accompanied by a set of practical results. Finally, we draw some conclusions about the future development of the Android malware analysis area. The main contribution of this chapter is a description of the realization of static and dynamic malware analysis techniques and principles that can be automated and mapped to software system tools in order to simplify analyses. Moreover, some details about the use of machine learning algorithms for malware classifications and the use of the hooking software techniques for dynamic analysis execution are provided