Estimate of halo ellipticity as a function of radius with flexions

The cold dark matter theory predicts triaxial dark matter haloes. The radial distribution of halo ellipticity depends on baryonic processes and the nature of dark matter particles (collisionless or collisional). Here we show that we can use lensing flexion ratios to measure the halo ellipticity as a function of radius. We introduce a weight function and study the relationship between the first and second order statistics of flexion ratios, both of which can be used to reduce the bias in the estimate of ellipticity. we perform numerical tests for our method, and demonstrate that it can reduce the bias and determine the halo ellipticity as a function of radius. We also point out that the minimum mean flexion ratio can be used to trace the centres of galaxy clusters.Comment: 9 pages,9 figures, MNRAS accepte

Ondernemen met bedrijfstoeslagen : een hele verandering?

Op 1 januari 2006 zijn in Nederland de Europese dier- en gewaspremies in het kader van het Gemeenschappelijk Landbouwbeleid (GLB) vervangen door bedrijfstoeslagen. In 2007 worden de melkpremies aan deze bedrijfstoeslagen toegevoegd. Ook de voorgestelde prijsverlaging van suikerbieten zal deels gecompenseerd worden in de vorm van bedrijfstoeslagen. Dit nieuwe systeem zou duidelijker moeten zijn dan het oude en zou de marktgerichtheid en duurzaamheid van de Europese landbouw moeten versterken. In dit rapport staat de vraag centraal of verwacht mag worden dat de doelen voor duidelijkheid, marktgerichtheid en duurzaamheid inderdaad verwezenlijkt zullen worden. On January 1 2006, the European support for animal husbandry and crop production from the Common Agricultural Policy (CAP) were replaced with single income payments. In 2007, the milk premiums will be added to the single payments. The price cut proposed for sugar beets will also be partly compensated through single income payments. The new system is supposed to be simpler than the old one and should stimulate market oriented and sustainable agricultural production in Europe. This report focuses on the question whether realisation of the goals for transparency, market orientation and sustainability may be expected. Informatie

Polarization of the excited states of twisted ethylene in a non-symmetrical environment

The polarization behavior of the low lying excited states in the vicinity of the perpendicularly twisted (D-2d) ethylene has been investigated in a quantum mechanical CISD approach, in which the quantum system was embedded in a polarized dielectric continuum modeling a non-symmetrical distribution of the solvent around the solute. The results show a strong polarization in the two lowest lying excited states in the region where the two vacuum energy surfaces of those states intersect, which strongly suggests that the lowering of the symmetry of the solvent shell can provide the adiabatic coupling for the avoided crossing between both potential energy surfaces. All examined values of epsilon, with the exception of the smallest investigated value(epsilon = 2.0), showed the polarization to keep intact on progressive twisting towards the perpendicular geometry