Prospects for asteroseismology

The observational basis for asteroseismology is being dramatically strengthened, through more than two years of data from the CoRoT satellite, the flood of data coming from the Kepler mission and, in the slightly longer term, from dedicated ground-based facilities. Our ability to utilize these data depends on further development of techniques for basic data analysis, as well as on an improved understanding of the relation between the observed frequencies and the underlying properties of the stars. Also, stellar modelling must be further developed, to match the increasing diagnostic potential of the data. Here we discuss some aspects of data interpretation and modelling, focussing on the important case of stars with solar-like oscillations.Comment: Proc. HELAS Workshop on 'Synergies between solar and stellar modelling', eds M. Marconi, D. Cardini & M. P. Di Mauro, Astrophys. Space Sci., in the press Revision: correcting abscissa labels on Figs 1 and

CATALYTIC PROPERTIES OF THE EUKARYOTIC EXOSOME

The eukaryotic exosome complex is built around the backbone of a 9‑subunit ring similar to phosporolytic ribonucleases such as RNase PH and polynucleotide phosphorylase (PNPase). Unlike those enzymes, the ring is devoid of any detectable catalytic activities, with the possible exception of the plant version of the complex. Instead, the essential RNA decay capability is supplied by associated hydrolytic ribonucleases belonging to the Dis3 and Rrp6 families. Dis3 proteins are endowed with two different activities: the long known processive 3′‑5′ exonucleolytic one and the recently discovered endonucleolytic one. Rrp6 proteins are distributive exonucleases. This chapter will review the current knowledge about the catalytic properties of theses nucleases and their interplay within the exosome holocomplex

The impact of the sandeel fishery closure in the northwestern North Sea on seabird food consumption, distribution and productivity

In the North Sea, the lesser sandeel (Ammodytes marinus) is the target of an industrial fishery and the principal prey of many top predators. Because of concerns about potential effects on predators, the sandeel fishery off eastern Scotland was closed in 2000, and local sandeel abundance increased subsequently. To examine whether closure benefitted sandeel-dependent seabirds, we compared summer sandeel consumption, at-sea distributions, and breeding success of seven species with fishery removals and abundance of older (1+ group) and young-of-the-year (0 group) sandeels from 1996 to 2003. Breeding success of black-legged kittiwake (Rissa tridactyla), a species that has declined in recent decades, was related to abundance of both 1+ group (the age class targeted by the fishery) and 0 group sandeels. The proportion of 0 group consumed by kittiwakes and proportion of the kittiwake population foraging in the area were linked to 0 group abundance. None of these parameters in the other seabird species were associated with sandeel abundance. Our results suggest that fishery closure can have a beneficial impact on top predators sensitive to variation in abundance of the target species, although environmental conditions before and after closure are also likely to be critically important