A disease evolution model with uncertain parameters

In this study we consider the SIS epidemiological model (susceptible-infected-susceptible) in which the transmission and recuperation rates are considered fuzzy sets. The concepts of possibility measures and fuzzy expectancy value are used to obtain the basic reproduction value for infected groups with different viral charge.

Thirring model with jump defect

The purpose of our work is to extend the formulation of classical affine Toda Models in the presence of jump defects to pure fermionic Thirring model. As a first attempt we construct the Lagrangian of the Grassmanian Thirring model with jump defect (of Backlund type) and present its conserved modified momentum and energy expressions giving a first indication of its integra-bility. Copyright © owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence.

Knowledge-based integrated Production Management Model applied to automotive companies

This paper aims to examine the relevance of a production management model, in the shop-floor operations environment, that integrates the dimensions of production organisation (lean and mass production), work organisation (enriched and semi-autonomous groups) and knowledge management. A theoretical model has been applied to automotive companies to verify model adherence. Each of those dimensions has been described by factors. Shop-floor personnel interviews were conducted to confirm the factors relevance to that company. Results have shown that the model represented the reality of those companies concerning the researched dimensions. The factors allow managers to promote a favourable context for knowledge sharing. © 2010 Inderscience Enterprises Ltd.

Neutrinos masses in a multi-higgs model with A 4 symmetry

Presently it is well known that neutrino oscillation data are well described by massive neutrinos and their mixing. This suggests changes in the standard model (SM) and makes the flavor physics even more interesting. Recently, it has been proposed a multi-Higgs extension of the SM with Abelian and non-Abelian discrete symmetries which seeks to explain the origin of the masses and mixing matrices in all charge sectors. © 2012 Elsevier B.V.

One-dimensional Fermi accelerator model with moving wall described by a nonlinear van der Pol oscillator

A modification of the one-dimensional Fermi accelerator model is considered in this work. The dynamics of a classical particle of mass m, confined to bounce elastically between two rigid walls where one is described by a nonlinear van der Pol type oscillator while the other one is fixed, working as a reinjection mechanism of the particle for a next collision, is carefully made by the use of a two-dimensional nonlinear mapping. Two cases are considered: (i) the situation where the particle has mass negligible as compared to the mass of the moving wall and does not affect the motion of it; and (ii) the case where collisions of the particle do affect the movement of the moving wall. For case (i) the phase space is of mixed type leading us to observe a scaling of the average velocity as a function of the parameter (χ) controlling the nonlinearity of the moving wall. For large χ, a diffusion on the velocity is observed leading to the conclusion that Fermi acceleration is taking place. On the other hand, for case (ii), the motion of the moving wall is affected by collisions with the particle. However, due to the properties of the van der Pol oscillator, the moving wall relaxes again to a limit cycle. Such kind of motion absorbs part of the energy of the particle leading to a suppression of the unlimited energy gain as observed in case (i). The phase space shows a set of attractors of different periods whose basin of attraction has a complicated organization. © 2013 American Physical Society.

Phenotypic plasticity of composite beef cattle performance using reaction norms model with unknown covariate

The objective of the present study was to determine the presence of genotype by environment interaction (G × E) and to characterize the phenotypic plasticity of birth weight (BW), weaning weight (WW), postweaning weight gain (PWG) and yearling scrotal circumference (SC) in composite beef cattle using the reaction norms model with unknown covariate. The animals were born between 1995 and 2008 on 33 farms located throughout all Brazilian biomes between latitude -7 and -31, longitude -40 and -63. The contemporary group was chosen as the environmental descriptor, that is, the environmental covariate of the reaction norms. In general, higher estimates of direct heritability were observed in extreme favorable environments. The mean of direct heritability across the environmental gradient ranged from 0.05 to 0.51, 0.09 to 0.43, 0.01 to 0.43 and from 0.12 to 0.26 for BW, WW, PWG and SC, respectively. The variation in direct heritability observed indicates a different response to selection according to the environment in which the animals of the population are evaluated. The correlation between the level and slope of the reaction norm for BW and PWG was high, indicating that animals with higher average breeding values responded better to improvement in environmental conditions, a fact characterizing a scale of G × E. Low correlation between the intercept and slope was obtained for WW and SC, implying re-ranking of animals in different environments. Genetic variation exists in the sensitivity of animals to the environment, a fact that permits the selection of more plastic or robust genotypes in the population studied. Thus, the G × E is an important factor that should be considered in the genetic evaluation of the present population of composite beef cattle. © The Animal Consortium 2012.

Higgs decay rate to two photons in a model with two fermiophobic-Higgs doublets

We consider a three Higgs doublet model with an S3 symmetry in which beside the standard model-like doublet, there are two fermiophobic doublets. Due to the new charged scalars, there is an enhancement in the two-photon decay, while the other channels have the same decay widths as the standard model neutral Higgs. The fermiophobic scalars are mass degenerated unless soft terms breaking the S3 symmetry are added. © 2013 American Physical Society.

Quantification of uncertainties associated with space-time estimates of short-term soil CO2 emissions in a sugar cane area

The characterization of soil CO2 emissions (FCO2) is important for the study of the global carbon cycle. This phenomenon presents great variability in space and time, a characteristic that makes attempts at modeling and forecasting FCO2 challenging. Although spatial estimates have been performed in several studies, the association of these estimates with the uncertainties inherent in the estimation procedures is not considered. This study aimed to evaluate the local, spatial, local-temporal and spatial-temporal uncertainties of short-term FCO2 after harvest period in a sugar cane area. The FCO2 was featured in a sampling grid of 60m×60m containing 127 points with minimum separation distances from 0.5 to 10m between points. The FCO2 was evaluated 7 times within a total period of 10 days. The variability of FCO2 was described by descriptive statistics and variogram modeling. To calculate the uncertainties, 300 realizations made by sequential Gaussian simulation were considered. Local uncertainties were evaluated using the probability values exceeding certain critical thresholds, while the spatial uncertainties considering the probability of regions with high probability values together exceed the adopted limits. Using the daily uncertainties, the local-spatial and spatial-temporal uncertainty (Ftemp) was obtained. The daily and mean emissions showed a variability structure that was described by spherical and Gaussian models. The differences between the daily maps were related to variations in the magnitude of FCO2, covering mean values ranging from 1.28±0.11μmolm-2s-1 (F197) to 1.82±0.07μmolm-2s-1 (F195). The Ftemp showed low spatial uncertainty coupled with high local uncertainty estimates. The average emission showed great spatial uncertainty of the simulated values. The evaluation of uncertainties associated with the knowledge of temporal and spatial variability is an important tool for understanding many phenomena over time, such as the quantification of greenhouse gases or the identification of areas with high crop productivity. © 2013 Elsevier B.V.

Quasi-Dirac neutrinos in a model with local B - L symmetry

In a model with B - L gauge symmetry, right-handed neutrinos may have exotic local B - L charge assignments: two of them with B - L = -4 and the other one having B - L = 5. Then, it is natural to accommodate the right-handed neutrinos with the same B - L charge in a doublet of the discrete S3 symmetry, and the third one in a singlet. If the Yukawa interactions involving right-handed neutrinos are invariant under S3, the quasi-Dirac neutrino scheme arises naturally in this model. However, we will show how in this scheme it is possible to give a value for θ13 in agreement with the Daya Bay results. For example the S3 symmetry has to be broken in the Yukawa interactions involving right-handed charged leptons. © 2013 IOP Publishing Ltd.

Some dynamical properties of a classical dissipative bouncing ball model with two nonlinearities

Some dynamical properties for a bouncing ball model are studied. We show that when dissipation is introduced the structure of the phase space is changed and attractors appear. Increasing the amount of dissipation, the edges of the basins of attraction of an attracting fixed point touch the chaotic attractor. Consequently the chaotic attractor and its basin of attraction are destroyed given place to a transient described by a power law with exponent -2. The parameter-space is also studied and we show that it presents a rich structure with infinite self-similar structures of shrimp-shape. © 2013 Elsevier B.V. All rights reserved.

Dynamical properties for an ensemble of classical particles moving in a driven potential well with different time perturbation

We consider dynamical properties for an ensemble of classical particles confined to an infinite box of potential and containing a time-dependent potential well described by different nonlinear functions. For smooth functions, the phase space contains chaotic trajectories, periodic islands and invariant spanning curves preventing the unlimited particle diffusion along the energy axis. Average properties of the chaotic sea are characterised as a function of the control parameters and exponents describing their behaviour show no dependence on the perturbation functions. Given invariant spanning curves are present in the phase space, a sticky region was observed and show to modify locally the diffusion of the particles. © 2013 Elsevier B.V.

Sleep quality and its associations with leisure-time exercise and excess weight among civil servants

O objetivo do estudo foi analisar a associação entre qualidade do sono, prática de exercícios físicos no lazer e obesidade entre servidores públicos de uma universidade. A amostra foi composta por 92 adultos de ambos os sexos. Qualidade do sono e atividade física foram coletadas por meio de questionário. O excesso de peso/obesidade foi diagnosticado pelo índice de massa corporal, o qual foi calculado com valores de peso e estatura relatados pelos avaliados. A prevalência de pessoas com sono alterado foi de 53,84%. Houve associação entre obesidade (OR= 7,22 [ORIC95%: 1,65-31,5]) e pior qualidade do sono, bem como, prática de atividade física e melhor qualidade do sono (OR= 0,19 [ORIC95%: 0,04-0,95]), independente de outros fatores de confusão. Concluiu-se que há alta ocorrência de distúrbios do sono, a qual foi associada de maneira independente com a prática de exercícios físicos e a obesidade.

Searches for electroweak neutralino and chargino production in channels with Higgs, Z, and W bosons in pp collisions at 8 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Health related quality of life is differently associated with leisure-time physical activity intensities according to gender: a cross-sectional approach

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

QCD chiral symmetry restoration with a large number of quarks in a model with a confining propagator and dynamically massive gluons

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)