673 research outputs found

    The Bogy Word Will Get You

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    (Honorable Mention, Essa.y Division, 1946, Butler Literary Contest) Writing in the British publication, Left, Major Lyall Wilkes, M.P., states that political labels mean nothing. Labels have about the same meaning in the United States. Every politican in this country claims he believes in democracy. And every politican does, for everyone in the United States does believe in democracy. And politicans being part of the people must believe in democracy

    La Vigilancia Meteorológica Mundial en la actualidad

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    Quasi-Periodic Pulsations during the Impulsive and Decay phases of an X-class Flare

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    Quasi-periodic pulsations (QPP) are often observed in X-ray emission from solar flares. To date, it is unclear what their physical origins are. Here, we present a multi-instrument investigation of the nature of QPP during the impulsive and decay phases of the X1.0 flare of 28 October 2013. We focus on the character of the fine structure pulsations evident in the soft X-ray time derivatives and compare this variability with structure across multiple wavelengths including hard X-ray and microwave emission. We find that during the impulsive phase of the flare, high correlations between pulsations in the thermal and non-thermal emissions are seen. A characteristic timescale of ~20s is observed in all channels and a second timescale of ~55s is observed in the non-thermal emissions. Soft X-ray pulsations are seen to persist into the decay phase of this flare, up to 20 minutes after the non-thermal emission has ceased. We find that these decay phase thermal pulsations have very small amplitude and show an increase in characteristic timescale from ~40s up to ~70s. We interpret the bursty nature of the co-existing multi-wavelength QPP during the impulsive phase in terms of episodic particle acceleration and plasma heating. The persistent thermal decay phase QPP are most likely connected with compressive MHD processes in the post-flare loops such as the fast sausage mode or the vertical kink mode.Comment: 7 pages, 4 figures, 1 tabl

    Detection and Interpretation Of Long-Lived X-Ray Quasi-Periodic Pulsations in the X-Class Solar Flare On 2013 May 14

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    Quasi-periodic pulsations (QPP) seen in the time derivative of the GOES soft X-ray light curves are analyzed for the near-limb X3.2 event on 14 May 2013. The pulsations are apparent for a total of at least two hours from the impulsive phase to well into the decay phase, with a total of 163 distinct pulses evident to the naked eye. A wavelet analysis shows that the characteristic time scale of these pulsations increases systematically from ∼\sim25 s at 01:10 UT, the time of the GOES peak, to ∼\sim100 s at 02:00 UT. A second ridge in the wavelet power spectrum, most likely associated with flaring emission from a different active region, shows an increase from ∼\sim40 s at 01:40 UT to ∼\sim100 s at 03:10 UT. We assume that the QPP that produced the first ridge result from vertical kink-mode oscillations of the newly formed loops following magnetic reconnection in the coronal current sheet. This allows us to estimate the magnetic field strength as a function of altitude given the density, loop length, and QPP time scale as functions of time determined from the GOES light curves and RHESSI images. The calculated magnetic field strength of the newly formed loops ranges from about ∼\sim500 G at an altitude of 24 Mm to a low value of ∼\sim10 G at 60 Mm, in general agreement with the expected values at these altitudes. Fast sausage mode oscillations are also discussed and cannot be ruled out as an alternate mechanism for producing the QPP

    Conclusion: Meditations on the Archaeology of Northern Plantations

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    A summary of the methods employed and the conclusions reached after nine seasons of archaeological fieldwork are presented. Emphasis is placed on the success and limitations of the methods employed in the investigations at Sylvester Manor and results of those investigations. Although excavations concentrated on the plantation core, additional areas examined produced little in the way of archaeological features. The results, although preliminary, point to a major role for Native Americans as laborers during the earliest phases of the plantation’s operation. Landscape evidence also suggests an evolving economy as the Manor transitions from a provisioning operation to a commercial farm/tenant run operation within a decade of Nathaniel Sylvester’s death in 1680. A third transition saw the commercial farm reconfigured once again as a Georgian-inspired country estate eclipsed it

    Dinâmica estacional de uma população de Anopheles darlingi, numa área endêmica de malária no Amazonas

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    The biting activity of Anopheles darlingi was studied for over a year in an endemic area of malaria - BR-174 (Manaus/Boa Vista). The biting activity was documented to show seasonal changes in population and variation in the cycle with changes of season. Data is presented for the outdoor biting cycle and indoor biting cycle collections. Patterns remained constant within the study area and the population of A. darlingi increases in dry season. Intense rainfall is accredited the decline in population - this decline corresponds to a similar seasonal decrease in the nunber of malaria cases.A atividade de picadas do Anopheles darlingi foi estudada por mais de um ano numa área endêmica de malária na BR-174 (Manaus/Boa Vista). Esta atividade foi documentada para demonstrar as mudanças estacionais na população e variação do ciclo nas estações do ano. São apresentadas as coletas mostrando o ciclo de picada dentro e fora das casas. O modelo foi constante na área estudada e verificou-se que a população de A. darlingi aumenta na estação seca. Com o aumento das chuvas há um declínio na população de anófeles e esta diminuição corresponde a um decréscimo estacional similar ao número de casos de infecção malárica

    Variações geográficas no ciclo de picada do Anopheles darlingi Root no Brasil

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    The biting behaviour of Anopheles darlingi Root from three areas in Brasil is compared and differences in the biting cycle are discussed.O comportamento e as diferenças no ciclo do ataque do Anopheles darlingi Root, em três localidades diferentes brasileiras, foram comparadas e discutidas

    Estudo sobre um surto de malária entre os índios Mayongong e Sanomã (Norte de Roraima) ()

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    In april, 1977, an outbreak of falciparum malaria occured in the Sanomã and Mayongong indian tribes in Brazil (Roraima) bordering Venezuela. Two hundred and sixty-eight indians were examined for malaria and 91 cases were found. Only one vector species, Anopheles darlingi was found, whose activities averaged 64 bites per man per night. Three cases of falciparum were resistant to chloroquine but responded favorably to Fansidar (sulphadoxina and pyrimethamine). There were distinct differences between tribes based on the proximity to the vector population. These differences are presented by age and sex. One group of Sanomã in an effort to escape malaria moved to a remote area, which interestingly was free of man-biting mosquitoes.Em abril de 1977 ocorreu um surto de malária falciparum nas Tribos Sanomã e Mayongong, em Roraima, na fronteira do Brasil e Venezuela. Duzentos e sessenta e oitc silvícolas foram examinados para malária e 91 casos foram positivos, dois para Plasmodium vivax e 89 para Plasmodium falciparum. O vetor responsável pela epidemia foi o Anopheles darlingi com uma atividade média de 64 picadas/homem por noite. Três casos de falciparum foram resistentes às cloroquinas. respondendo favoravelmente ao Fansidar (sulfadoxina e pirimetamina). Houve diferença distinta nas duas tribos baseada na proximidade da população do vetor. Essas diferenças foram apresentadas por idade e sexo. Foi interessante a descoberta de um grupo de Sanomã que, no esforço para livrar-se ao ataque da malária, fugiu para outra área. Este grupo foi encontrado em localidade que não possuia mosquitos
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