845 research outputs found

    Vortices in simulations of solar surface convection

    Full text link
    We report on the occurrence of small-scale vortices in simulations of the convective solar surface. Using an eigenanalysis of the velocity gradient tensor, we find the subset of high vorticity regions in which the plasma is swirling. The swirling regions form an unsteady, tangled network of filaments in the turbulent downflow lanes. Near-surface vertical vortices are underdense and cause a local depression of the optical surface. They are potentially observable as bright points in the dark intergranular lanes. Vortex features typically exist for a few minutes, during which they are moved and twisted by the motion of the ambient plasma. The bigger vortices found in the simulations are possibly, but not necessarily, related to observations of granular-scale spiraling pathlines in "cork animations" or feature tracking.Comment: 11 pages, 13 figures, accepted for publication in A&A, complementary movies at http://www.mps.mpg.de/homes/moll/strudel/papermovies

    A Quest for Justice in Cuzco, Peru:Race and Evidence in the Case of Mercedes Ccorimanya Lavilla

    Get PDF
    The life of Mercedes Ccorimanya Lavilla renders a telling portrait of the pursuit of justice in Cuzco, Peru, revealing how courts of law can be key sites in the production and negotiation of racial and gender taxonomies. Mercedes (who was gang-raped as a young woman) illustrates the near-heroic efforts necessary to mount and pursue rape charges in Peruvian courts, where rape victims largely manage the construction of evidence in lieu of the state. In the following article, I reconstruct the social circumstances and legal institutional setting surrounding the rape trial of Mercedes Ccorimanya Lavilla through the use of historical and ethnographic materials. In arguing that race mutually defines women's sexuality in rural Peru, I show how (in order to achieve a conviction) Mercedes had to develop a strategy in which she instrumentally employed the languages of race to distance herself from her own indigeneity, as well as that of her alleged attackers

    The RNA-binding protein ELAV regulates Hox RNA processing, expression and function within the Drosophila nervous system

    Get PDF
    The regulated head-to-tail expression of Hox genes provides a coordinate system for the activation of specific programmes of cell differentiation according to axial level. Recent work indicates that Hox expression can be regulated via RNA processing but the underlying mechanisms and biological significance of this form of regulation remain poorly understood. Here we explore these issues within the developing Drosophila central nervous system (CNS). We show that the pan-neural RNA-binding protein (RBP) ELAV (Hu antigen) regulates the RNA processing patterns of the Hox gene Ultrabithorax (Ubx) within the embryonic CNS. Using a combination of biochemical, genetic and imaging approaches we demonstrate that ELAV binds to discrete elements within Ubx RNAs and that its genetic removal reduces Ubx protein expression in the CNS leading to the respecification of cellular subroutines under Ubx control, thus defining for the first time a specific cellular role of ELAV within the developing CNS. Artificial provision of ELAV in glial cells (a cell type that lacks ELAV) promotes Ubx expression, suggesting that ELAVdependent regulation might contribute to cell type-specific Hox expression patterns within the CNS. Finally, we note that expression of abdominal A and Abdominal B is reduced in elav mutant embryos, whereas other Hox genes (Antennapedia) are not affected. Based on these results and the evolutionary conservation of ELAV and Hox genes we propose that the modulation of Hox RNA processing by ELAV serves to adapt the morphogenesis of the CNS to axial level by regulating Hox expression and consequently activating local programmes of neural differentiation

    Extreme right-wing voting in Western Europe

    Get PDF
    In this study we explain extreme right-wing voting behaviour in the countries of the European Union and Norway from a micro and macro perspective. Using a multidisciplinary multilevel approach, we take into account individual-level social background characteristics and public opinion alongside country characteristics and characteristics of extreme right-wing parties themselves. By making use of large-scale survey data (N = 49,801) together with country-level statistics and expert survey data, we are able to explain extreme right-wing voting behaviour from this multilevel perspective. Our results show that cross-national differences in support of extreme right-wing parties are particularly due to differences in public opinion on immigration and democracy, the number of non-Western residents in a country and, above all, to party characteristics of the extreme right-wing parties themselves
    corecore