Interregional differences in taxes and population mobility

Belgium is a federal state where regional fiscal competences have been increasing. In particular, the regions are now able to increase or to lower the personal income tax burden of their residents via positive and negative surcharges. Should the regions adopt the possibilities opened by the Law, would it influence interregional mobility? It is not possible to assert directly this question. However, indirect evidence of the impact of fiscal disparities on mobility can be found by analysing the mobility between municipalities. Indeed, for long, the real estate income tax and the local surcharges on the federal personal income tax have not been uniform on the Belgian territory. We tried to quantify whether those tax differences generated population moves from the more expensive municipalities to the less expensive ones. The attractiveness of the municipalities measured by means of their intra Belgium migration balance has been explained by local wealth, employment rate, quality of the local administration, proximity to the coast, three indexes constructed by a factor analysis based on a satisfaction survey, housing prices and local taxation. Our estimations showed that local tax level has no significant impact on the local migration balance. Is this observation transposable at the regional level? On one side, the answer to this question depends on the level of disparities in tax rates that such a practice would introduce. On the other side, if disparities in regional tax were to appear, interregional mobility would be slowed down by the impact of the interregional cultural differences.

Pattern de pigmentation et contraintes développementales: les sites d'attachement des muscles du vol délimitent le trident thoracique de Drosophila melanogaster

International audienceIn their seminal paper published in 1979, Gould and Lewontin argued that some traits arise as by-products of the development of other structures and not for direct utility in themselves. We show here that this applies to the trident, a pigmentation pattern observed on the thorax of Drosophila melanogaster. Using reporter constructs, we show that the expression domain of several genes encoding pigmentation enzymes follows the trident shape. This domain is complementary to the expression pattern of stripe (sr), which encodes an essential transcription factor specifying flight muscle attachment sites. We demonstrate that sr limits the expression of these pigmentation enzyme genes to the trident by repressing them in its own expression domain, i.e. at the flight muscle attachment sites. We give evidence that repression of not only yellow but also other pigmentation genes, notably tan, is involved in the trident shape. The flight muscle attachment sites and sr expression patterns are remarkably conserved in dipterans reflecting the essential role of sr. Our data suggest that the trident is a by-product of flight muscle attachment site patterning that arose when sr was co-opted for the regulation of pigmentation enzyme coding genes

To better understand the formation of short-chain acids in combustion systems

International audienceOur study aims at a better control and understanding of the transfer of a complex [DNA supercoiled plasmid - dodecyltrimethylammonium surfactant] layer from a liquid-vapour water interface onto a silicon surface without any additional cross-linker. The production of the complexed layer and its transfer from the aqueous subphase to the substrate is achieved with a Langmuir-Blodgett device. The substrate consists of a reconstructed boron doped silicon substrate with a nanometer-scale roughness. Using X-ray photoelectron spectroscopy and atomic force microscopy measurements, it is shown that the DNA complexes are stretched in a disorderly manner throughout a 2-4 nm high net-like structure. The mechanism of transfer of this layer onto the planar surface of the semi-conductor and the parameters of the process are analysed and illustrated by atomic force microscopy snapshots. The molecular layer exhibits the typical characteristics of a spinodal decomposition pattern or dewetting features. Plasmid molecules appear like long flattened fibers covering the surface, forming holes of various shapes and areas. The cluster-cluster aggregation of the complex structure gets very much denser on the substrate edge. The supercoiled DNA plasmids undergo conformational changes and a high degree of condensation and aggregation is observed