HYBRID RICE AND ITS IMPACT ON FOOD SECURITY AND THE PATTERN OF GLOBAL PRODUCTION AND TRADE

The hybrid rice technology is one of the many ways in which productivity of scarce resources devoted to rice production could be enhanced, with the consequent alleviation of food insecurity. The findings of this study show that the hybrid rice technology has so far made some sizable contributions to per-capita availability of rice in adopting countries with marginal spillover effects to other regions. However, at forecasted population growths, a massive intensification of adoption would be needed to maintain per-capita availability of rice at baseline levels. But even with adoption rates climbing significantly, much higher equilibrium prices are expected, which will represent a challenge for the hungry in many parts of the world. While hybrid rice has the potential to contribute significantly to improve production and food security, more efforts are needed to improve the productivity of the constraining production resources.hybrid rice, food security, technology change, Demand and Price Analysis, Food Security and Poverty, International Relations/Trade, Research and Development/Tech Change/Emerging Technologies, Q16, Q55,

Management Control- International Observatory 2011

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Résultats de l’enquête internationale 2012 « Quelles activités, quels processus, quelles méthodes, quels systèmes », Observatoire International du Contrôle de Gestion

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Composite mirror facets for ground based gamma ray astronomy

Composite mirrors for gamma-ray astronomy have been developed to fulfill the specifications required for the next generation of Cherenkov telescopes represented by CTA (Cherenkov Telescope Array). In addition to the basic requirements on focus and reflection efficiency, the mirrors have to be stiff, lightweight, durable and cost efficient. In this paper, the technology developed to produce such mirrors is described, as well as some tests that have been performed to validate them. It is shown that these mirrors comply with the needs of CTA, making them good candidates for use on a significant part of the array.Comment: 16 pages, 13 figures, accepted to be published on NIM

Thermal Casimir Effect in the Plane-Sphere Geometry

The thermal Casimir force between two metallic plates is known to depend on the description of material properties. For large separations the dissipative Drude model leads to a force a factor of 2 smaller than the lossless plasma model. Here we show that the plane-sphere geometry, in which current experiment are performed, decreases this ratio to a factor of 3/2, as revealed by exact numerical and large distance analytical calculations. For perfect reflectors, we find a repulsive contribution of thermal photons to the force and negative entropy values at intermediate distances.Comment: 4 pages, 3 figure

Consequences of anisotropy in electrical charge storage: application to the characterization by the mirror method of TiO2 rutile

This article is devoted first to anisotropic distributions of stored electric charges in isotropic materials, second to charge trapping and induced electrostatic potential in anisotropic dielectrics. On the one hand, we examine the case of anisotropic trapped charge distributions in linear homogeneous isotropic (LHI) insulators, obtained after an electron irradiation in a scanning electron microscope. This injection leads to the formation of a mirror image

Résultats de l’Enquête internationale 2013 « Quelles activités, quels processus, quelles méthodes, quels systèmes »

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Modélisation des effets hydrochimiques à long terme des dépôts acides et des reboisements dans les bassins versants du Mont-Lozère (Sud de la France)

L'évolution de la chimie des sols et des eaux dans trois petits bassins-versants subméditerranéens granitiques recevant d'importants apports atmosphériques de S04 et de poussières sahariennes a été simulée, de 1845 à 2125, en utilisant le modèle MAGIC. Ce modèle biogéochimique global comporte une série de relations d'équilibre entre les phases gazeuse, liquide et solide (adsorption de soufre, solubilité de l'aluminium, échanges cationiques, système C02/carbonates, dissociation des acides organiques) et une comptabilisation des flux d'éléments (entrées atmosphériques, sorties hydrologiques, immobilisation biologique, altération). Les bassins versants diffèrent par l'historique récente de leur utilisation par l'homme : la pelouse pâturée qui les recouvraient en 1845 n'a subsisté que dans un bassin : elle a été remplacée vers 1930 par une pessière dans l'un des bassins, et colonisée, après abandon, par une hêtraie dans l'autre. Les simulations montrent que le bassin couvert de pelouse a peu souffert de l'augmentation de l'acidité des pluies au cours du XXe siècle, et pourrait subir les apports actuels pendant plus de 100 ans sans dommage. Les deux bassins forestiers s'acidifient fortement depuis 1970 par les effets combinés de la pollution et des reboisements. Pour la pessière, seule une réduction d'au moins 60 % des apports soufrés permettrait d'inverser le processus. Le vieillissement naturel de la hêtraie produirait une amélioration même sans réduction des dépôts acides, en diminuant le taux d'assimilation de cations. Les deux facteurs acidifiants agissent donc en synergie, mais dans le cas de la pessière l'augmentation des apports acides due à l'effet filtrant des frondaisons est prépondérant, alors que dans la hêtraie, la forte immobilisation cationique dans la biomasse perenne jolie un plus grand rôle.Introduction. The combined acidifying effects of afforestation and acid deposition are well documented for sites in North-Western Europe and North America. In acid-sensitive mediterranean areas, acidification has been delayed by lower deposition rates and alkaline aeolian dust input to the ecosystems. Here, the evolution of stream water and soil chemistry, from 1845 to 2125, in three small submediterranean catchments of Southern France, is assessed using the MAGIC model.Sites and methods. Three granitic catchments have been monitored since 1981 in the South-Eastern Massif Central. The mean elevation is 1300 m above sea level and the soils are rankers and acid brown earth. The catchments are submitted to heavy atmospheric deposition of industrial acidic oxides (mainly sulphate : more than 20 kg.ha-1•year-1 of S-S04) and of alkaline saharan dust. The land use was similar in all the catchments up to 1930, and consisted mainly of extensive sheep grazing on semi natural grassland. Then one catchment (19.5 ha) was afforested with conifers (spruce), another catchment (54 ha) was abandoned and progressively settled by a beech coppice, while the other catchment (81 ha) remained covered with grassland. MAGIC is a lumped, process-oriented biogeochemical model, where the soil physical and chemical characteristics are described by a single set of mean variables. The processes in soils are modelled by a series of equilibrium equations : Aluminium solubility, cation exchange, sulphate adsorption, C02 and carbonates equllibria, organic acids dissociation. The changes in the stocks of elements are calculated from the main input, output and internal fluxes : atmospheric deposition, river load, biological uptake and weathering. The calibration aims to get the best fit between measured and simulated values to the « target variables », i.e., the present day exchangeable cations amounts in soils and river chemical composition. Hindcast and forecast runs need historical and prospective scenarios for atmospheric deposition, dry deposition factor, nutrient uptake and discharge. Here, the growth of the forest was modelled by increasing dry deposition factor and nutrient uptake and decreasing the discharge according to the field observations. The sequence of sulphate deposition was derived from S02 emission data. Three scenarios were tested in the forecasts : a constant deposition al the present level, a 30 % reduction and a 60 % reduction within 2010. In both cases, the nutrient uptake of the spruce stand and grassland was kept constant, white those of the beech coppice was progressively decreased to simulate a natural ageing of the forest.Results. The model successfully reproduced the chemistry of the catchments. The values of the optimised parameters suggest that :- the soils of the area have a very high sulphate adsorption capacity;- the weathering rates are similar in the three catchments except for the calcium (lower in the beech catchment) and the magnesium (much higher in the spruce catchment);- the initial conditions calculated by the model for 1845 are slightly different; the alkalinity and cations concentrations are lower, and the base saturation higher, in the beech catchment.The simulations show that for the grassland catchment, there has been little change due to increasing of S04 wet deposition over the last 100 years. The simulations for the other two catchments (beech and spruce stands) show that they have been acidifying since 1970 due to the combined effects of air pollution and afforestation. This trend could lead to a severe decline of soil base saturation and streamwater quality by 2050. Concerning the coniferous catchment, only a 60 % reduction of the sulphur input could allow a recovery. The natural ageing of the beech stand, resulting in a decrease of the biological uptake, would permit a recovery even under constant sulphur deposition.Conclusion. This exercise show that although the effects afforestation and acid deposition are synergetical and difficult to distinguish, their relative importance in acidification processes varies according to the vegetation. In the spruce catchment, the enhanced deposition due to the scavenging properties of the canopy is the determining factor. If no emission reduction occurs and no mitigating measures are taken, the decline of soil and water quality is a serious threat. In the beech catchment, the dynamics of biological uptake prevail, because the trees store a large amount of base cations. If the stand is allowed to age, a recovery can be observed even if no sulphur emission reduction occurs. This is also partly due, in this context, to the scavenging of the alkaline aeolian dust