Scintillations
Mostrando 1-4 de 4 artigos, teses e dissertações.
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1. Morfologia e dinâmica das irregularidades ionosféricas de pequena escala e imageamento ionosférico por GPS / Morphology and dynamic of small-scale ionospheric irregularities and ionospheric imaging by GPS
The signals received from the Global Positioning System (GPS) satellites were used to study the behavior of three important geophysical parameters of the ionosphere: small-scale irregularities, their zonal drift velocities and the Total Electron Content (TEC). From the fluctuations (scintillations) in the amplitude of the GPS L1 signal (1575.42 MHz), detecte
Publicado em: 2008
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2. Efeitos de tempestades magnéticas em sinais de gps, em Natal, Brasil
Sinais de satélites apresentam perturbações (cintilações), devido à presença de irregularidades no plasma ionosférico. No presente trabalho, dedicamo-nos ao estudo da atenuação dessas cintilações ou seja, uma melhoria no sinal, durante a fase principal de tempestades magnéticas presentes no peróodo de outubro 2006 a fevereiro 2007. Usando-se da
Publicado em: 2008
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3. Estudo das irregularidades ionosféricas equatoriais utilizando sinais GPS / Global positioning system studies of equatorial ionospheric irregularities
Signals transmitted by the Global Positioning System (GPS) satellites were used to study equatorial ionospheric irregularities over Brazil. GPS (L1=1.575 GHz) scintillation data were used to infer the occurrence of ~400m scale-size irregularities and compared with equatorial Spread F (ESF) observations carried out by several other instruments like VHF cohere
Publicado em: 2003
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4. Mechanisms of migraine aura revealed by functional MRI in human visual cortex
Cortical spreading depression (CSD) has been suggested to underlie migraine visual aura. However, it has been challenging to test this hypothesis in human cerebral cortex. Using high-field functional MRI with near-continuous recording during visual aura in three subjects, we observed blood oxygenation level-dependent (BOLD) signal changes that demonstra
The National Academy of Sciences.