Science and Society in Dialogue About Marker Assisted Selection

Analysis of a European Union funded biotechnology project on plant genomics and marker assisted selection in Solanaceous crops shows that the organization of a dialogue between science and society to accompany technological innovations in plant breeding faces practical challenges. Semi-structured interviews with project participants and a survey among representatives of consumer and other non-governmental organizations show that the professed commitment to dialogue on science and biotechnology is rather shallow and has had limited application for all involved. Ultimately, other priorities tend to prevail because of high workload. The paper recommends including results from previous debates and input from societal groups in the research design phase (prior to communication), to use appropriate media to disseminate information and to make explicit how societal feedback is used in research, in order to facilitate true dialogue between science and society on biotechnology

Impact environnemental des pneumatiques déchiquetés utilisés pour la construction d’ouvrages en remblai

Les pneumatiques usagés sont employés comme matériau de construction pour des ouvrages de génie civil et de géotechnique depuis les années 80. S’agissant de déchets, leur impact sur l’environnement doit être évalué, au regard de l’application visée et de la réglementation en vigueur. Cet article porte sur l’impact environnemental de pneumatiques usagés déchiquetés, lorsqu'ils sont utilisés en mélange avec du sable, pour la construction d’ouvrages en remblai. Des essais de lixiviation, de percolation et au lysimètre ont été réalisés, sur le matériau vierge et sur son résidu après incendie. Les liquides collectés ont été l’objet d’analyses physico-chimiques, considérant deux cents composés, et écotoxicologiques sur une bactérie et un crustacé. Les mesures révèlent un impact très limité en contexte normal. Par contre, les résidus après incendie doivent être envoyés en installation de stockage pour déchets dangereux. / This article deals with the assessment of the environmental impact of shredded scrap tyres mixed with sand to built embankments. Tests of leaching, of percolation and in a lysimeter were performed on the raw material as well as on the tailing resulting from fire. The liquids were analysed looking for 200 compounds and their toxicity on a shellfish and a bacterium was assessed. Measurements confirm the limited consequences on the environment, except in the case of fire, where tailings must be considered as hazardous waste

NAM-SCA: A Nonhydrostatic anelastic model with segmentally constant approximations

International audienceAn atmospheric convective system may be modeled as an ensemble of discrete plume elements. A representation of decomposited plumes provides the basis for mass-flux convective parameterization. A dry version of such a prototype model is constructed in a two-dimensional horizontally periodic domain. Each discrete plume element is approximated by a horizontally homogeneous segment such that the whole system is given by segmentally constant approximations (SCA) in the horizontal direction for each vertical level in a nonhydrostatic anelastic model (NAM). The distribution of constant segments is highly inhomogeneous in space and evolves with time in a highly adaptive manner. The basic modeling strategy from a physical point of view is to activate new segments vertically upward with time when a convective plume is growing and to deactivate segments when a plume event is over. The difference in physical values crossing segment interfaces is used as a criterion for numerically implementing this strategy. Whenever a large difference is found, the given interface is stretched vertically by subdividing an existing segment into two. In turn, when a segment interface difference is found below the threshold, the given interface is removed, thereby merging the two segments into one. This nonhydrostatic anelastic model with segmentally constant approximations (NAM-SCA) is tested on an idealized atmospheric convective boundary layer. It successfully simulates the evolution of convective plumes with a relatively limited number of segments (i.e., high compression) and with a much scarcer distribution of segments over nonplume environments (i.e., extremely inhomogeneous distribution of segments). Overall, this method compresses the size of the model up to 5 times compared to a standard NAM with homogeneous grid distribution without substantially sacrificing numerical accuracy. © 2010 American Meteorological Society

Low Mach number modeling of Type I X-ray burst deflagrations

The Low Mach Number Approximation (LMNA) is applied to 2D hydrodynamical modeling of Type I X-ray bursts on a rectangular patch on the surface of a non-rotating neutron star. Because such phenomena involve decidedly subsonic flows, the timestep increase offered by the LMNA makes routine simulations of these deflagrations feasible in an environment where strong gravity produces significant stratification, while allowing for potentially significant lateral differences in temperature and density. The model is employed to simulate the heating, peak, and initial cooling stages in the deep envelope layers of a burst. During the deflagration, Benard-like cells naturally fill up a vertically expanding convective layer. The Mach number is always less than 0.15 throughout the simulation, thus justifying the low Mach number approximation. While the convective layer is superadiabatic on average, significant fluctuations in adiabaticity occur within it on subconvective timescales. Due to convective layer expansion, significant compositional mixing naturally occurs, but tracer particle penetration through the convective layer boundaries on convective timescales is temporary and spatially limited. Thus, mixing occurs on the relatively slow burst timescale through thermal expansion of the convective layer rather than from mass penetration of the convective layer boundary through particle convection. At the convective layer boundaries where mixing is less efficient, the actual temperature gradient more closely follows the Ledoux criteria.Comment: 40 pages, 13 figures, accepted by ApJ, high resolution version: http://www.astro.northwestern.edu/~lin/references/Lin_LMNA_ApJ_2006.pd