1,297 research outputs found
Fallback disks, magnetars and other neutron stars
The presence of matter with angular momentum, in the form of a fallback disk around a young isolated neutron star will determine its evolution. This leads to an understanding of many properties of different classes of young neutron stars, in particular a natural explanation for the period clustering of AXPs, SGRs and XDINs. The spindown or spinup properties of a neutron star are determined by the dipole component of the magnetic field. The natural
possibility that magnetars and other neutron stars may have different strengths of the dipole and higher multipole components of the magnetic field is now actually required by observations on the spindown rates of some magnetars. This talk gives a broad overview and some applications of the fallback disk model to particular neutron stars. Salient points are: (i) A fallback disk has already been observed around the AXP 4U 0142+61 some years ago. (ii) The low observed
spindown rate of the SGR 0418+5729 provides direct evidence that the dipole component of the field is in the 1012G range. All properties of the SGR 0418+5729 at its present age can be explained by spindown under torques from a fallback disk. (iii) The anomalous braking index of PSR J1734-3333 can also be explained by the fallback disk model which gives the luminosity, period, period derivative and the period second derivative at the present age. (iv) These and all applications to a variety of other sources employ the same disk physics and evolution, differing only in the initial conditions of the disk
Spacelike intersection curve of three spacelike hypersurfaces in
In this paper, we compute the Frenet vectors and the curvatures of the spacelike intersection curve of three spacelike hypersurfaces given by their parametric equations in four-dimensional Minkowski space
A plasma membrane H+ATPase gene is germinationinduced in wheat embryos
The expression pattern of a germination specific plasma membrane H+-ATPase was analyzed by RTPCR and in situ RNA hybridization methods. RT-PCR results revealed that germination specific plasma membrane H+-ATPase accumulation was detectable in all organs and tissues of germinating wheat embryos. H+-ATPase expression was not observed in dry wheat embryos and in immature wheat embryos. In situ RNA hybridization indicated that germination specific plasma membrane H+-ATPase gene expression was associated with all organs of germinating wheat tissues. The accumulation of H+- ATPase mRNA was more heavily on the cells of vascular bundles and epidermal cells of coleoptiles.Since germination specific plasma membrane H+-ATPase gene was identified as a growth related gene, interest was focused on the activity of growth regulators (GA, IAA, ABA) and stress factors, NaCl and Mannitol, on H+-ATPase gene expression. The results indicated that there were not any dramatic changes in the accumulation of germination specific plasma membrane H+-ATPase gene in any case. More rigorous analysis is necessary to evaluate the effect of growth regulators on germination specific plasma membrane H+-ATPase
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