X-ray polarimetric signatures induced by spectral variability in the framework of the receding torus model

Obscuring circumnuclear dust is a well-established constituent of active galactic nuclei (AGN). Traditionally referred to as the receding dusty torus, its inner radius and angular extension should depend on the photo-ionizing luminosity of the central source. Using a Monte Carlo approach, we simulate the radiative transfer between the multiple components of an AGN adopting model constraints from the bright Seyfert galaxy NGC 4151. We compare our model results to the observed near-IR to UV polarization of the source and predict its X-ray polarization. We find that the 2-8 keV polarization fraction of a standard AGN model varies from less then a few percent along polar viewing angles up to tens of percent at equatorial inclinations. At viewing angles around the type-1/type-2 transition the X-ray polarization variability differs between a static or a receding torus scenario. In the former case, the expected 2-8 keV polarization of NGC 4151 is found to be 1.21% +/- 0.34% with a constant polarization position angle, while in the later scenario it varies from 0.1% to 6% depending on the photon index of the primary radiation. Additionally, an orthogonal rotation of the polarization position angle with photon energy appears for very soft primary spectra. Future X-ray polarimetry missions will be able to test if the receding model is valid for Seyfert galaxies seen at a viewing angle close to the torus horizon. The overall stability of the polarization position angle for photon indexes softer than {\Gamma} = 1.5 ensures that reliable measurements of X-ray polarization are possible. We derive a long-term observational strategy for NGC 4151 assuming observations with a small to medium-size X-ray polarimetry satellite.Comment: 10 pages, 8 Figures, accepted for publication in A&

Pyramidal Fisher Motion for Multiview Gait Recognition

The goal of this paper is to identify individuals by analyzing their gait. Instead of using binary silhouettes as input data (as done in many previous works) we propose and evaluate the use of motion descriptors based on densely sampled short-term trajectories. We take advantage of state-of-the-art people detectors to define custom spatial configurations of the descriptors around the target person. Thus, obtaining a pyramidal representation of the gait motion. The local motion features (described by the Divergence-Curl-Shear descriptor) extracted on the different spatial areas of the person are combined into a single high-level gait descriptor by using the Fisher Vector encoding. The proposed approach, coined Pyramidal Fisher Motion, is experimentally validated on the recent `AVA Multiview Gait' dataset. The results show that this new approach achieves promising results in the problem of gait recognition.Comment: Submitted to International Conference on Pattern Recognition, ICPR, 201

Efeito de variáveis meteorológicas sobre a evapotranspiração de referência em uma região de clima tropical úmido do Brasil.

A evapotranspiração de referência (ETo) é função de diversas variáveis meteorológicas, como radiação solar, temperatura e umidade do ar além da velocidade do vento. Conforme as condições climáticas locais e a época do ano, essas variáveis têm importância diferenciada na estimativa da ETo. A região de Jales é uma das principais áreas vitícolas do Estado de São Paulo, Brasil. Buscando ampliar o conhecimento relacionado com a determinação das necessidades hídricas da viticultura, o presente trabalho teve como objetivo estudar o efeito das diferentes variáveis meteorológicas sobre a ETo durante o período chuvoso na região

Avaliação de dados de radiação solar na escala diária modelada a partir de sensor remoto orbital para o Brasil.

Nesse trabalho, avaliou-se um método do qual se obtém dados estimados de radiação solar diária, derivados de satélites por banco de dados do Nasa-Power, já utilizado nos Estados Unidos, Argentina e Austrália, e que vem apresentando resultados satisfatórios quando comparados com os dados observados das estações automáticas

Parametrização do modelo CANEGRO para as cultivares brasileiras de cana-de-açúcar.

O objetivo do presente trabalho foi a parametrização do modelo CANEGRO para a as cultivares brasileiras IAC 91-1099 e SP 89 1115.Trabalho apresentado na V Mostra de Trabalhos de Estagiários e Bolsistas, Campinas, out. 2009