Site-specific management units in a commercial maize plot delineated using very high resolution remote sensing and soil properties mapping

14 Pags. The definitive version, with tabls. and figs., is available at: http://www.sciencedirect.com/science/journal/01681699The joint use of satellite imagery and digital soil maps derived from soil sampling is investigated in the present paper with the goal of proposing site-specific management units (SSMU) within a commercial field plot. Very high resolution Quickbird imagery has been used to derive leaf area index (LAI) maps in maize canopies in two different years. Soil properties maps were obtained from the interpolation of ion concentrations (Na, Mg, Ca, K and P) and texture determined in soil samples and also from automatic readings of electromagnetic induction (EMI) readings taken with a mobile sensor. Links between the image-derived LAI and soil properties were established, making it possible to differentiate units within fields subject to abiotic stress associated with soil sodicity, a small water-holding capacity or flooding constraints. In accordance with the previous findings, the delineation of SSMUs is proposed, describing those field areas susceptible of variable-rate management for agricultural inputs such as water or fertilizing, or soil limitation correctors such as gypsum application in the case of sodicity problems. This demonstrates the suitability of spatial information technologies such as remote sensing and digital soil mapping in the context of precision agriculture.The Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA) funded the PhD grant of the first author. This work is a result of the project RTA2005-00230, funded by INIA. The contribution of the project AGL2009-08931/AGR is also recognized.Peer reviewe

Coulombic Energy Transfer and Triple Ionization in Clusters

Using neon and its dimer as a specific example, it is shown that excited Auger decay channels that are electronically stable in the isolated monomer can relax in a cluster by electron emission. The decay mechanism, leading to the formation of a tricationic cluster, is based on an efficient energy-transfer process from the excited, dicationic monomer to a neighbor. The decay is ultrafast and expected to be relevant to numerous physical phenomena involving core holes in clusters and other forms of spatially extended atomic and molecular matter.Comment: 5 pages, 1 figure, to be published in PR

Contribution of microstructural parameters to strengthening in an ultrafine-grained Al-7%Si alloy processed by severe deformation

An Al-7%Si alloy was severely deformed by equal channel angular pressing (ECAP) to study the refinement of the microstructure and associated changes of mechanical properties. The initial coarse dendritic structure was broken into an elongated sub-micron grain/subgrain structure, with high dislocation density, and distributed fine Si particles. The Si particles in the composite are seen to induce a high dislocation density during deformation and lead to faster structural refinement than in a monolithic alloy with the same composition as the matrix. The additional strengthening of the composite relative to the monolithic alloy is due to both the finer grain size and the high retained dislocation density. Severe plastic deformation leads also to an improvement of the ductility of the strong material due to the refinement of both matrix microstructure and the Si particlesWe should like to acknowledge financial support of the Spanish Ministry of Education and Science under project number MAT2003-01540, as well as the award of a Juan de la Cierva post-doctoral fellowship for one of the authors (I.G.)Peer reviewe

Superstructure compression in binary compounds of AB and А3В compositions

The paper focuses on the formation of metallic compounds depending on the relation between several atom parameters among which is the size factor. The analysis of the binary compounds of intermetallic alloys with the simple stoichiometric compounds of АВ and А3В is presented in this paper. The block diagrams are plotted for various structures depending on th [delta] [omega]/[omega] size factor. Close-packed lattice structures are investigated herein