4,931 research outputs found
Aproximative solutions to the neutrino oscillation problem in matter
We present approximative solutions to the neutrino evolution equation
calculated by different methods. In a two neutrino framework, using the
physical parameters which gives the main effects to neutrino oscillations from
nu{e} to another flavors for L=3000Km and E=1GeV, the results for the
transition probability calculated by using series solutions, by to take the
neutrino evolution operator as a product of ordered partial operators and by
numerical methods, for a linearly and sinusoidally varying matter density are
compared. The extension to an arbitrary density profile is discussed and the
evolution operator as a product of partial operators in the three neutrino case
is obtained.Comment: 12 pages, 5 figure
Management of the Rice Tungro Virus Vector \u3ci\u3eNephotettix virescens\u3c/i\u3e (Homoptera: Cicadellidae) with Controlled-Release Formulations of Carbofuran
Field trials were conducted in lowland flooded rice in the Philippines to evaluate a number of carbofuran controlled-release formulations in comparison with commercial formulations. The test formulations were based on a biodegradable matrix of pine kraft lignin and were used as granules of different sizes and also in the form of small strips. The release rates were assessed under field conditions by bioassaying rice plants in the field, using adult rice green leafhopper, Nephotettix virescens Distant. The lignin formulations with a high level of active ingredient (15–45% by weight) gave as good or better control than the commercial 3% granules in tests based on three application techniques: broadcast into the floodwater, soil incorporation, and root zone injection. The improvements in control levels of green leafhoppers were most marked with soil incorporation and root zone application. The best lignin-based formulation reduced levels of tungro virus infection from 23% for a conventional flowable carbofuran formulation to 1.0% at an application rate of 0.5 kg (AI)/ha. At the same rate, the grain yield was increased from 3.56 t/ha to 5.5 t/ha, using the controlled-released formulation
UOLO - automatic object detection and segmentation in biomedical images
We propose UOLO, a novel framework for the simultaneous detection and
segmentation of structures of interest in medical images. UOLO consists of an
object segmentation module which intermediate abstract representations are
processed and used as input for object detection. The resulting system is
optimized simultaneously for detecting a class of objects and segmenting an
optionally different class of structures. UOLO is trained on a set of bounding
boxes enclosing the objects to detect, as well as pixel-wise segmentation
information, when available. A new loss function is devised, taking into
account whether a reference segmentation is accessible for each training image,
in order to suitably backpropagate the error. We validate UOLO on the task of
simultaneous optic disc (OD) detection, fovea detection, and OD segmentation
from retinal images, achieving state-of-the-art performance on public datasets.Comment: Publised on DLMIA 2018. Licensed under the Creative Commons
CC-BY-NC-ND 4.0 license: http://creativecommons.org/licenses/by-nc-nd/4.0
Characterization of Vehicle Behavior with Information Theory
This work proposes the use of Information Theory for the characterization of
vehicles behavior through their velocities. Three public data sets were used:
i.Mobile Century data set collected on Highway I-880, near Union City,
California; ii.Borl\"ange GPS data set collected in the Swedish city of
Borl\"ange; and iii.Beijing taxicabs data set collected in Beijing, China,
where each vehicle speed is stored as a time series. The Bandt-Pompe
methodology combined with the Complexity-Entropy plane were used to identify
different regimes and behaviors. The global velocity is compatible with a
correlated noise with f^{-k} Power Spectrum with k >= 0. With this we identify
traffic behaviors as, for instance, random velocities (k aprox. 0) when there
is congestion, and more correlated velocities (k aprox. 3) in the presence of
free traffic flow
Structural Changes in Data Communication in Wireless Sensor Networks
Wireless sensor networks are an important technology for making distributed
autonomous measures in hostile or inaccessible environments. Among the
challenges they pose, the way data travel among them is a relevant issue since
their structure is quite dynamic. The operational topology of such devices can
often be described by complex networks. In this work, we assess the variation
of measures commonly employed in the complex networks literature applied to
wireless sensor networks. Four data communication strategies were considered:
geometric, random, small-world, and scale-free models, along with the shortest
path length measure. The sensitivity of this measure was analyzed with respect
to the following perturbations: insertion and removal of nodes in the geometric
strategy; and insertion, removal and rewiring of links in the other models. The
assessment was performed using the normalized Kullback-Leibler divergence and
Hellinger distance quantifiers, both deriving from the Information Theory
framework. The results reveal that the shortest path length is sensitive to
perturbations.Comment: 12 pages, 4 figures, Central European Journal of Physic
The spectroscopic evolution of the recurrent nova T Pyxidis during its 2011 outburst. II.The optically thin phase and the structure of the ejecta in recurrent novae
We continue our study of the physical properties of the recurrent nova T Pyx,
focussing on the structure of the ejecta in the nebular stage of expansion
during the 2011 outburst. The nova was observed contemporaneously with the
Nordic Optical Telescope (NOT), at high resolution spectroscopic resolution (R
~ 65000) on 2011 Oct. 11 and 2012 Apr. 8 (without absolute flux calibration),
and with the Space Telescope Imaging Spectrograph (STIS) aboard the Hubble
Space Telescope, at high resolution (R ~ 30000) on 2011 Oct. 10 and 2012 Mar.
28 (absolute fluxes). We use standard plasma diagnostics (e.g. [O III] and [N
II] line ratios and the H line fluxes) to constrain electron densities
and temperatures. Using Monte Carlo modeling of the ejecta, we derive the
structure and filling factor from comparisons to the optical and ultraviolet
line profiles. The ejecta can be modeled using an axisymmetric conical --
bipolar -- geometry with a low inclination of the axis to the line of sight,
i=15+/-5 degrees, compatible with published results from high angular
resolution optical spectro-interferometry. The structure is similar to that
observed in the other short orbital period recurrent novae during their nebular
stages. We show that the electron density scales as as expected from a
ballistically ejected constant mass shell; there is no need to invoke a
continuing mass outflow following the eruption. The derived mass for the ejecta
with filling factor f ~ 3%, M_ej ~ 2E-6$M_sun is similar to that obtained for
other recurrent nova ejecta but inconsistent with the previously reported
extended optically thick epoch of the explosion. We suggest that the system
underwent a common envelope phase following the explosion that produced the
recombination event. Implications for the dynamics of the recurrent novae are
discussed. (truncated)Comment: accepted for publication in A&A (10 Nov. 2012), 10 pgs, 16 fig
The spectroscopic evolution of the -ray emitting classical nova Nova Mon 2012. I. Implications for the ONe subclass of classical novae
Nova Mon 2012 was the first classical nova to be detected as a high energy
-ray transient, by Fermi-LAT, before its optical discovery. We study a
time sequence of high resolution optical echelle spectra (Nordic Optical
Telescope) and contemporaneous NOT, STIS UV, and CHIRON echelle spectra (Nov
20/21/22). We use [O III] and H line fluxs to constrain the properties
of the ejecta. We derive the structure from the optical and UV line profiles
and compare our measured line fluxes for with predictions using Cloudy with
abundances from other ONe novae. Mon 2012 is confirmed as an ONe nova. We find
E(B-V)=0.850.05 and hydrogen column density
cm. The corrected continuum luminosity is nearly the same in the entire
observed energy range as V1974 Cyg, V382 Mon, and Nova LMC 2000 at the same
epoch after outburst. The distance, about 3.6 kpc, is quite similar to V1974
Cyg. The line profiles can be modeled using an axisymmetric bipolar geometry
for the ejecta with various inclinations of the axis to the line of sight, 60
\le i \le 80 degrees, an opening angle of \approx\Delta
R/R(t)\approx 0.4f\approx 0.1-0.3\leq 6\times
10^{-5}_\odot\gamma$-ray emission may be a generic phenomenon, common to all ONe novae,
possibly to all classical novae, and connected with acceleration and emission
processes within the ejecta (abstract severely truncated).Comment: Submitted to A&A 9/1/2013; Accepted 27/2/2013 (in press
Desenvolvendo o raciocínio de estudantes brasileiros de ensino médio
[Resumo] Este trabalho investiga a eficácia de um programa de promoção cognitiva na melhora do desempenho escolar de jovens adolescentes, na faixa etária de 13 a 20 anos, de urna escola agrotécnica, ou seja, de formação para técnicos agrícolas, localizada no sul do Brasil. o interesse nessa investigação baseia-se, fundamentalmente, na realidade educacional brasileira,
caracterizada por sérios problemas de aprendizado. Aliado a isto, encontramos hoje um mercado
de trabalho que nao admite mais profissionais que nao sejam criativos e que nao tenham capacidade
para administrar de maneira equilibrada sua vida pessoal e profissional. o programa de promoção.cognitiva de Almeida e Morais (1996) tem o objetivo de possibilitar que o indivíduo aumente sua inteligencia através do desenvolvimento do raciocínio. Para verificar sua adequação arealidade brasileira, o programa foi aplicado durante tres meses, obedecendo rigorosamente suas etapas. Ele é composto por quinze sess6es, nas quais sao trabalhadas situações do cotidiano com o propósito de melhorar a auto-estima, satisfação no trabalho, persistencia e assertividade, sucesso na resolução de problemas pessoais e níveis de desempenho. Adotou-se o Plano Solomon para quatro grupos, organizados da seguinte forma: um grupo recebeu pré-teste, programa de promoção cognitiva e pós-teste; um segundo grupo recebeu pré e pós-teste; um terceiro recebeu programa de promo<;ao e pós-teste; o quarto grupo recebeu apenas pós-teste. As variáveis dependentes foram divididas em dois grupos: desempenho acadernico e desempenho cognitivo.Para avaliar o desempenho academico foram utilizados: notas das disciplinas Matemática, Química e Portugues; avaliações dos professores de cada urna das disciplinas, alem da auto-avaliação dos alunos. Para avaliar o desempenho cognitivo, foi utilizada a bateria de Pravas de Raciocínio Diferencial
(Alrneida L.,1986) que mede dificuldades no aprendizado e é composta por cinco testes: raciocínio
numérico, verbal, espacial abstrato e mecanico, tendo-se excluído o teste de raciocínio mecanico.
Os resultados indicaram a melhora dos alunos tanto no desempenho academico como no cognitivo,
registrando-se urna melhora mais acentuada na disciplina Portugues e menos acentuada em
Matemática. Interpretamos estes resultados como consequencia do bom rendimento já existente em
Matemática e da dificuldade em Portugues, função da forte influencia dos idiomas alemao, italiano,
polones e indígena existentes na região. Concluímos que o programa mostrou-se eficaz tanto a nível academico como cognitivo, evidenciando a necessidade de incluí-lo como atividade extra curricular rotineira, para que os resultados sejam ainda mais significativos
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