Green's functions for far-side seismic images: a polar expansion approach

We have computed seismic images of magnetic activity on the far surface of the Sun by using a seismic-holography technique. As in previous works, the method is based on the comparison of waves going in and out of a particular point in the Sun but we have computed here the Green's functions from a spherical polar expansion of the adiabatic wave equations in the Cowling approximation instead of using the ray-path approximation previously used in the far-side holography. A comparison between the results obtained using the ray theory and the spherical polar expansion is shown. We use the gravito-acoustic wave equation in the local plane-parallel limit in both cases and for the latter we take the asymptotic approximation for the radial dependencies of the Green's function. As a result, improved images of the far-side can be obtained from the polar-expansion approximation, especially when combining the Green's functions corresponding to two and three skips. We also show that the phase corrections in the Green's functions due to the incorrect modeling of the uppermost layers of the Sun can be estimated from the eigenfrequencies of the normal modes of oscillation.Comment: 8 pages, 5 figures, Astrophysical Journal, accepted (2010

Development Communication: 1. History and Theories

This entry includes three articles, each dealing with a different aspect of the subject: History and Theories Alternative Systems Projects The first and third cover predominantly the Western (especially the U.S.) approach; the second raises some criticisms directed at both the theoretical and the practical limitations of the Western perspective and presents alternative views

Computers, the internet, and cheating among secondary school students: Some implications for educators

This article investigates in greater depth one particular aspect of cheating within secondary education and some implications for measuring academic achievement. More specifically, it examines how secondary students exploit the Internet for plagiarizing schoolwork, and looks at how a traditional method of educational assessment, namely paper-based report and essay writing, has been impacted by the growth of Internet usage and the proliferation of computer skills among secondary school students. One of the conclusions is that students’ technology fluency is forcing educators to revisit conventional assessment methods. Different options for combating Internet plagiarism are presented, and some software tools as well as non-technology solutions are evaluated in light of the problems brought about by “cyberplagiarism.

Las Dimensiones Ocultas Del Metabolismo Social: Ensayo Fenomenológico Sobre El Ser Y Su Relación Con La Energía

In contemporary scientific language social metabolism distinguishes the energy exchange that occurs in all human interactions and throughout the human-Nature interface This exchange consists of processes of energy flows commonly referred to as transfers of energy-matter the object of study under physical and biological spheres as well as energy-spirit transfers which human understanding recognizes as experience Experience in turn may be derived from our individual conscience and communitarian responsibility which is also understood as lively experience This essay offers two distinct approximations to analyze social metabolism The approximations herein complement one another under a phenomenological approach to experience First the narrative behind the trajectory of ecological economics as a discipline originally presented as an alternative path to standard approaches in Economics Standard or mainstream approaches in Economics often posit arguments based on logical-positivist premises that are in serious need of normative frameworks Standard approaches in economics fall short of seeking a real compensation to third party victims affected by an externalization of costs without contemplating the value in situ and in spirit of natural capita

Littlest Inverse Seesaw Model

We propose a minimal predictive inverse seesaw model based on two right-handed neutrinos and two additional singlets, leading to the same low energy neutrino mass matrix as in the Littlest Seesaw (LS) (type I) model. In order to implement such a Littlest Inverse Seesaw (LIS) model, we have used an $S_{4}$ family symmetry, together with other various symmetries, flavons and driving fields. The resulting LIS model leads to an excellent fit to the low energy neutrino parameters, including the prediction of a normal neutrino mass ordering, exactly as in the usual LS model. However, unlike the LS model, the LIS model allows charged lepton flavour violating (CLFV) processes and lepton conversion in nuclei within reach of the forthcoming experiments.Comment: 17 pages, 9 figures. Published versio