Asteroseismic Theory of Rapidly Oscillating Ap Stars

This paper reviews some of the important advances made over the last decade concerning theory of roAp stars.Comment: 9 pages, 5 figure

Asteroseismology and Magnetic Cycles

Small cyclic variations in the frequencies of acoustic modes are expected to be a common phenomenon in solar-like pulsators, as a result of stellar magnetic activity cycles. The frequency variations observed throughout the solar and stellar cycles contain information about structural changes that take place inside the stars as well as about variations in magnetic field structure and intensity. The task of inferring and disentangling that information is, however, not a trivial one. In the sun and solar-like pulsators, the direct effect of the magnetic field on the oscillations might be significantly important in regions of strong magnetic field (such as solar- / stellar-spots), where the Lorentz force can be comparable to the gas-pressure gradient. Our aim is to determine the sun- / stellar-spots effect on the oscillation frequencies and attempt to understand if this effect contributes strongly to the frequency changes observed along the magnetic cycle. The total contribution of the spots to the frequency shifts results from a combination of direct and indirect effects of the magnetic field on the oscillations. In this first work we considered only the indirect effect associated with changes in the stratification within the starspot. Based on the solution of the wave equation and the variational principle we estimated the impact of these stratification changes on the oscillation frequencies of global modes in the sun and found that the induced frequency shifts are about two orders of magnitude smaller than the frequency shifts observed over the solar cycle.Comment: 4 pages, 6 figures, ESF Conference: The Modern Era of Helio- and Asteroseismology, to be published on 3 December 2012 at Astronomische Nachrichten 333, No. 10, 1032-103

Self-esteem and body image evaluation in adolescent girls

info:eu-repo/semantics/publishedVersio

Tomographic Characterization of Three-Qubit Pure States with Only Two-Qubit Detectors

A tomographic process for three-qubit pure states using only pairwise detections is presented.Comment: 3 pages; revtex4; v2: the focus on tomography was emphasized and the experimental procedure detailed; v3: the text was improved in clarity, some mistakes were correcte