Search results for " croissance"
showing 10 items of 20 documents
Root-induced decomposer growth and plant N uptake are not positively associated among a set of grassland plants
2007
Abstract It is known that plant species can induce development of different soil decomposer communities and that they differ in their influence on organic matter decomposition and N mineralization in soil. However, no study has so far assessed whether these two observations are related to each other. Based on the hypothesis that root-induced growth of soil decomposers leads to accelerated decomposition of SOM and increased plant N availability in soil, we predicted that (1) among a set of grassland plants the abundance of soil decomposers in the plant rhizosphere is positively associated with plant N uptake from soil organic matter. To test this, we established grassland microcosms consisti…
Study of TiO2 nanostructures grown in a MOCVD reactor in presence of metallic catalysts. Valorization of these TiO2 nanostructures
2017
Within the Nanoform Theme, Ax Nanosciences, ICB, we realize the growth of 1D, 2D and 3D hybrid nanostructures based on TiO2 by MOCVD. Our work deals with the theoretical aspect of the formation of these nanostructures (growth and kinetic models, structure and texture) and the study of photoelectric, optical and physicochemical properties as well as the development of applications of these structures in physics (random laser), photocatalysis, energy (solar cells). Under certain perfectly controlled conditions, we obtain original TiO2 structures not yet described in the literature: membranes, rods , canals, crucibles, COHN (COaxiales Heterostructures Nanowires). Our previous work made it poss…
Etude de l’interaction plante-communautés microbiennes de la rhizosphère chez l’espèce modèle Medicago truncatula par une approche multidisciplinaire…
2012
The soil microbial communities can improve plant growth by increasing soil nutrient availability, thereby promoting their uptake by the plant. In an overall context of input reduction, the plant nutrition should be increasingly based on plant- rhizosphere microbial communities’ interactions. Yet, very few studies have examined the entire rhizosphere microbial communities in relationship with both plant genotype and phenotype. The aim of this thesis was to study the plant genotype effect on the rhizosphere microbial communities in relationship with the plant nutritional strategies. To do so, the plant-rhizosphere microbial communities’ interaction was assessed by a multidisciplinary approach…
Services provided by soil microorganisms to improve plant phosphate nutrition
2022
Since the first Green Revolution, agricultural practices have been based on the massive use of synthetic fertilisers and plant protection products. Since then, global consumption of phosphate fertilisers has more than tripled, reaching 47 million tonnes in 2019. Current projections estimate that phosphate rock stocks (natural phosphorus resources for fertiliser production) could be depleted within the next century, leading us to change our agricultural practices. In soils, P is mainly present in complexed forms that are not easily accessible to plants. To reduce the use of phosphate fertilisers, it is necessary to make this complexed phosphate accessible to plants. This can be done by benef…
Responsabilité d'une commune pour non-respect du Code du travail
2001
International audience
Endogenous growth and regional growth (Approaches to a theory of spatial endogenous growth)
1994
L'objectif de cet article est de poser les différents principes préalables à la construction d'une théorie spatiale de la croissance endogène. Dans cebut, plusieurs étapes sont présentées.1/ L'analyse des théories macroéconomiques de la croissance endogène permet de mettre en évidence le rôle clé des externalités d'agglomérations.2/ Mettre en parallèle, les mécanismes de croissance endogène et de croissance régionale permet d'identifier les composantes spatiales de lacroissance. A cet égard, le concept de capital spatial est défini.3/ Enfin, les principes fondamentaux attachés à la dynamique de population, à l'accumulation du capital spatial et à l'émergence des économiesd'agglomération son…
The endogeneous nature of the dynamic analysis among classical economist's writings
1998
« Endogenous growth theories » exhibit different models in which growth is assumed to come from the accumulation of a particular factor (human capital, technology, public infrastructures, etc.). However, due to its newness, the real term of « endogenous growth » seems to playdown old theories.This paper intends to put right this position and demonstrate that relations displayed by current models are only formalizations stemming from the developments of classical economists. In the end, we demonstrate that their analysis yields new viewpoints for analysts. Overall, we wish to reinforce theendogenous nature of the dynamic analysis among classical economist's writings.
Sur la fonction croissance des variétés riemanniennes
2012
Nous donnons un aperçu du degré de différentiabilité de la fonction croissance des variétés riemanniennes ainsi que de ses singularités en dimension 2.
Les effets macroéconomiques sur la productivité et les prix de vastes réformes structurelles sur les marchés des biens et du travail
2015
La présente analyse vise à caractériser les effets « directs » et « indirects » des régulations sur le marché des biens ainsi que les effets des régulations sur le marché du travail, sur la productivité et sur les prix. L’analyse est empirique et réalisée via des estimations sur un panel de quatorze pays sur la période 1987-2007, et quand cela est possible sur des donnés sectorielles (treize secteurs manufacturiers et cinq secteurs des services et réseaux). Au terme de ces estimations, il est possible de caractériser les effets de la mise en oeuvre de réformes structurelles. Les réformes structurelles consistent ici en une baisse des indicateurs de régulations sur les marchés des biens et d…
"On-the-go" multispectral imaging system embedded on a track laying tractor to characterize the vine foliage
2015
Mutispectral imaging systems are widely used in remote sensing for Precision Viticulture. In this work, this technique was applied in the proximal sensing context to characterize vine foliage. A mobile terrestrial experimental system is presented, composed of a GPS receiver, a multi-spectral camera acquiring visible and near infrared images, and a Greenseeker RT-100 which measures the Normalized Difference Vegetative Index (NDVI). This optical system observes vine foliage in the trellis plan, in natural sunlight. The experimental field is planted with Chardonnay, Pinot Noir and Meunier cultivars in a latin squared pattern. In 2013, six datasets were acquired at various phenological stages.S…