61,775 research outputs found

    Observations of Plasma Upflow in a Warm Loop with Hinode/EIS

    Get PDF
    A complete understanding of Doppler shift in active region loops can help probe the basic physical mechanism involved into the heating of those loops. Here we present observations of upflows in coronal loops detected in a range of temperature temperatures (log T=5.8 - 6.2). The loop was not discernible above these temperatures. The speed of upflow was strongest at the footpoint and decreased with height. The upflow speed at the footpoint was about 20 km/s in Fe VIII which decreased with temperature being about 13 km/s in Fe X, about 8 km/s in Fe XII and about 4 km/s in FeXIII. To the best of our knowledge this is the first observation providing evidence of upflow of plasma in coronal loop structures at these temperatures. We interpret these observations as evidence of chromospheric evaporation in quasi-static coronal loops.Comment: 14 pages, 5 figures, Accepted for Publication in The Astrophysical Journal Letter

    Tests regarding parameters of several independent gamma populations

    Get PDF
    Gamma distribution has been used with considerable success in reliability studies and life testing experiments. This distribution assumes various forms as its shape parameter varies which makes it suitable for analyzing a variety of lifetime data. In such studies, often interest lies in comparing a lifetime distribution over multiple groups. In this paper, we develop asymptotic tests for comparing shape parameters of k independent gamma distributions. We also develop similar tests to compare both, the shape and scale parameters, simultaneously. The tests are based on generalized minimum chi-square procedure. This procedure has been known to produce estimators which are asymptotically e±cient and the tests based on such estimators are known to have high asymptotic power.Gamma distribution, minimum chi-square, general linear hypothesis, shape and scale parameters, multiple groups.

    Data Abstraction Mechanisms in Sina/st

    Get PDF
    This paper describes a new data abstraction mechanism in an object-oriented model of computing. The data abstraction mechanism described here has been devised in the context of the design of Sina/st language. In Sina/st no language constructs have been adopted for specifying inheritance or delegation, but rather, we introduce simpler mechanisms that can support a wide range of code sharing strategies without selecting one among them as a language feature. Sina/st also provides a stronger data encapsulation than most of the existing object-oriented languages. This language has been implemented on the SUN 3 workstation using Smalltalk

    CRISPR/Cas9 editing of endogenous banana streak virus in the B genome of Musa spp. overcomes a major challenge in banana breeding

    Get PDF
    Open Access Journal; Published online: 31 Jan 2019Presence of the integrated endogenous banana streak virus (eBSV) in the B genome of plantain (AAB) is a major challenge for breeding and dissemination of hybrids. As the eBSV activates into infectious viral particles under stress, the progenitor Musa balbisiana and its derivants, having at least one B genome, cannot be used as parents for crop improvement. Here, we report a strategy to inactivate the eBSV by editing the virus sequences. The regenerated genome-edited events of Gonja Manjaya showed mutations in the targeted sites with the potential to prevent proper transcription or/and translational into functional viral proteins. Seventy-five percent of the edited events remained asymptomatic in comparison to the non-edited control plants under water stress conditions, confirming inactivation of eBSV into infectious viral particles. This study paves the way for the improvement of B genome germplasm and its use in breeding programs to produce hybrids that can be globally disseminated
    corecore