1,400 research outputs found

    Was the GLE on May 17, 2012 linked with the M5.1-class flare the first in the 24th solar cycle?

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    On May 17, 2012 an M5.1-class flare exploded from the sun. An O-type coronal mass ejection (CME) was also associated with this flare. There was an instant increase in proton flux with peak at 100\geq 100 MeV, leading to S2 solar radiation storm level. In about 20 minutes after the X-ray emission, the solar particles reached the Earth.It was the source of the first (since December 2006) ground level enhancement (GLE) of the current solar cycle 24. The GLE was detected by neutron monitors (NM) and other ground based detectors. Here we present an observation by the Tupi muon telescopes (Niteroi, Brazil, 220.9S22^{0}.9 S, 430.2W43^{0}.2 W, 3 m above sea level) of the enhancement of muons at ground level associated with this M5.1-class solar flare. The Tupi telescopes registered a muon excess over background 20%\sim 20\% in the 5-min binning time profile. The Tupi signal is studied in correlation with data obtained by space-borne detectors (GOES, ACE), ground based neutron monitors (Oulu) and air shower detectors (the IceTop surface component of the IceCube neutrino observatory). We also report the observation of the muon signal possibly associated with the CME/sheath striking the Earth magnetosphere on May 20, 2012. We show that the observed temporal correlation of the muon excess observed by the Tupi muon telescopes with solar transient events suggests a real physical connection between them. Our observation indicates that combination of two factors, the low energy threshold of the Tupi muon telescopes and the location of the Tupi experiment in the South Atlantic Anomaly region, can be favorable in the study and detection of the solar transient events. Our experiment provides new data complementary to other techniques (space and ground based) in the study of solar physics.Comment: 9 pages, 10 figure

    Insulin-mediated increases in arterial baroreflex control of muscle sympathetic nerve activity following meal intake in humans [abstract]

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    Animal studies indicate that insulin enhances arterial baroreflex (ABR) control of sympathetic nerve activity (SNA); however, the extent to which these findings can be extrapolated to humans is unknown. To begin to address this, we utilized a mixed meal as a physiological method to evoke sustained increases in plasma insulin

    Spatial distribution of two symmetric four-wave mixing signals induced by Gaussian beams

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    We present a theoretical analysis of the spatial shape of two symmetric signals of degenerate four-wave mixing induced by Gaussian beams in a thin sample of two-level atoms. Our calculations take into account the full spatial and spectral dependencies of the relevant nonlinear susceptibilities that govern the two processes. This reveals two interesting effects. The first one is that the total power of incident beams affects the transverse profile of the four-wave mixing signals at the medium exit and their free propagation. The second one is the influence of the spectral characteristics of the medium on the longitudinal profile of both generated signals upon free propagation. We argue that the first effect can be seen as the saturation of the medium in regions of higher intensity, while the second can be understood as the result of a nonlinear contribution to the refractive index inside the atomic medium. These effects can be symmetric between the two signals, with asymmetries induced by different detunings from resonance of the incident fields

    Zoneamento agroclimático para cana-de-açúcar no continente africano.

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    O zoneamento agrícola da cana de açúcar tem como objetivo fornecer subsídios técnicos para formulação de políticas públicas à expansão e produção sustentável. Neste trabalho foi realizado o zoneamento de aptidão climática e pedológica para a cana-de-açúcar no continente africano, onde os principais indicadores considerados na elaboração foram a temperatura, a deficiência hídrica, a declividade e o tipo de solo. Foi possível identificar as áreas mais adequadas ao cultivo da cana-de-açúcar e as regiões onde há restrições para seu desenvolvimento. O presente trabalho teve como objetivo avaliar a aptidão climática e pedológica da cana de açúcar no continente africano.Trabalho apresentado na V Mostra de Trabalhos de Estagiários e Bolsistas, Campinas, out. 2009

    A lei da inovação tecnológica na Embrapa Clima Temperado.

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