1,951 research outputs found

    Decay Phase Cooling and Inferred Heating of M- and X-class Solar Flares

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    In this paper, the cooling of 72 M- and X-class flares is examined using GOES/XRS and SDO/EVE. The observed cooling rates are quantified and the observed total cooling times are compared to the predictions of an analytical 0-D hydrodynamic model. It is found that the model does not fit the observations well, but does provide a well defined lower limit on a flare's total cooling time. The discrepancy between observations and the model is then assumed to be primarily due to heating during the decay phase. The decay phase heating necessary to account for the discrepancy is quantified and found be ~50% of the total thermally radiated energy as calculated with GOES. This decay phase heating is found to scale with the observed peak thermal energy. It is predicted that approximating the total thermal energy from the peak is minimally affected by the decay phase heating in small flares. However, in the most energetic flares the decay phase heating inferred from the model can be several times greater than the peak thermal energy.Comment: Published in the Astrophysical Journal, 201

    A descriptive catalog of the Mollusca of Utah

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    journal articleIn the preparation of this bulletin an effort has been made to bring together what was previously known of recent Utah mollusks and to incorporate with this the results of the authors' special studies. The form of presentation has been determined by the fact that, in the first place, the paper is intended to serve as a basis for further scientific work and, in the second place, to serve as a reference text for teachers of zoology in Utah colleges and high schools and as an aid to amateur collectors. The article is based primarily upon a study of upward of one thousand sets of shells collected during the year 1927 and a lesser number collected during 1928, all of which are now deposited in the Zoological Museum o.f the University of Utah

    Reply to ``Comment on `Hole-burning experiments within glassy models with infinite range interactions' ''

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    This is a reply to the comments by Richter and Chamberlin, and Diezemann and Bohmer to our paper (Phys. Rev. Lett. 85, 3448 (2000)). As further evidence for the claims in this Letter, we here reproduce the nonlinear spectral hole-burning experimental protocol in an equilibrated fully connected spin-glass model and we exhibit frequency selectivity, together with a shift in the base of the spectral hole.Comment: 1 page, two figures, to appear in Phys. Rev. Let

    Thermal Evolution and Radiative Output of Solar Flares Observed by the EUV Variability Experiment (EVE)

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    This paper describes the methods used to obtain the thermal evolution and radiative output during solar flares as observed by the Extreme u ltraviolet Variability Experiment (EVE) onboard the Solar Dynamics Ob servatory (SDO). Presented and discussed in detail are how EVE measur ements, due to its temporal cadence, spectral resolution and spectral range, can be used to determine how the thermal plasma radiates at v arious temperatures throughout the impulsive and gradual phase of fla res. EVE can very accurately determine the radiative output of flares due to pre- and in-flight calibrations. Events are presented that sh ow the total radiated output of flares depends more on the flare duration than the typical GOES X-ray peak magnitude classification. With S DO observing every flare throughout its entire duration and over a la rge temperature range, new insights into flare heating and cooling as well as the radiative energy release in EUV wavelengths support exis ting research into understanding the evolution of solar flares

    O método das múltiplas hipóteses de trabalho

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    Tradução realizada em 1995 por Gilberto Amaral, IG-Unicamp, do original em Inglês: Chamberlin T.C. 1897. The method of multiple working hypotheses. J.Geology 5:837-848.Tradução realizada em 1995 por Gilberto Amaral, IG-Unicamp, do original em Inglês: Chamberlin T.C. 1897. The method of multiple working hypotheses. J.Geology 5:837-848.82115119sem informaçãosem informaçãoGeologi

    Developmental patterning in the Caenorhabditis elegans hindgut

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    AbstractDevelopmental pattern formation allows cells within a tissue or organ to coordinate their development and establish cell types in relationship to one another. To better characterize the developmental patterning events within one organ, the C. elegans hindgut, we have analyzed the expression pattern of several genes using green fluorescent protein-based reporter transgenes. In wild-type animals, these genes are expressed in subsets of hindgut cells rather than in individual cell types. In mutant animals, we find that some, but not all, genes expressed in cells with altered development exhibit a corresponding alteration of gene expression. The results are consistent with a model where a combination of factors contribute to each cell's fate, and address how developmental information converges to specify cell types
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