Search results for "Zone"

Etude de l'importance du transfert de sulfate au sein des nodosités pour la synthèse des peptides NCR riche en cystéine nécessaire à la différenciati…

2018

La transition socio-écologique, une opportunité pour co-construire le futur de l'Europe

2015

International audience

Zones humides

2018

International audience

Complémentarité des données de télédétection pour l'analyse des transformations de l'occupation du sol dans des zones humides urbaines. Application a…

2008

International audience; Dans le cadre d'un programme ECOS-Nord, notre étude analyse les transformations récentes de l'occupation du sol sur deux zones humides urbaines : les hortillonnages d'Amiens et les chinampas de Mexico. Malgré des contextes différents, ces deux espaces sont les supports d'usages et de dynamiques très similaires : des techniques identiques d'agriculture sur l'eau et un déclin de l'activité agricole au XXe siècle au profit de celle des loisirs. L'objectif est double : identifier et quantifier les changements sur chacun des sites, puis les confronter de façon à mettre en évidence les points communs et les spécificités locales, tant dans la nature des changements, que dan…

Natures urbaines en conflit. Écoquartiers, patrimoine et potagers militants

2014

International audience; Si la « nature » semble aujourd’hui constituée en bien commun dans la ville, les modalités de « l’alliance entre nature et ville » représentent un enjeu de luttes. Prenant l’exemple de deux controverses dans l’agglomération de Dijon, où des projets d’écoquartiers se heurtent à divers mouvements d’opposition (une association de résidants dans un cas, un collectif libertaire dans l’autre), nous décrivons comment s’opposent dans le débat public différents acteurs sociaux et différentes mises en valeur de la naturalité comme idéal urbain. Nous montrons alors que la « demande sociale » de nature en ville ne va pas de soi : elle est socialement contrastée et âprement dispu…

De quelques difficultés à cumuler ses savoirs sur les phénomènes éducatifs : l'exemple de la démocratisation de l'enseignement

2002

This paper aims at showing the difficulties regarding the building up of knowledge about educational processes, especially as far as democratization is concerned. The stake here is to boost the scientific character of results in educational research, and therefore its legitimacy and its influence upon educational policies. The authors stress the importance of the historical context of data, the leading part of conceptualization, so that the structural changes of schooling may be grasped, and also the impact of technical measures upon factual knowledge. Finally, the issue of data, a difficult one in that field like in other ones, is illustrated by the analysis of the relation between "ZEP" (…

Les effets de la livraison à domicile sur l’accès aux produits alimentaires : le cas des grandes surfaces alimentaires et des cybermarchés de l’aire …

2012

The population's access to groceries varies with the kind of spaces people live in (center vs periphery). If a large part of peri-urban peoples do not experience difficulties in accessing to supermarkets, some of them will face more difficulties. For these households, home delivery may reduce disparities of access between spaces and improve access to a wider assortment of groceries. The empirical work of this study is mainly based on the census of offers from several statistical sources, and a survey by interviews with local actors of home delivery. Our results show that home delivery supply is spatially concentrated. The delivery areas tend to promote a little more the populations of the c…

La sous-traitance de la messagerie urbaine : logiques économiques et rapports de dépendance

2014

Subcontracting is a common practice in road transport, especially in parcel transport operations. Parcel transport is defined as the collection and distribution of shipments of less than three tons. Deliveries and pick-up rounds in urban areas present some specificities (such as difficult traffic and parking situations) which contribute in the high the use of subcontracting within the parcel transport sector. Sub-contracting allows parcel carriers to minimize the costs of urban trips and to provide a flexible and cost-efficient service to shippers. We analyzed a 2012 'carriers' survey done in the Paris region as well as an earlier survey made in the Lyon region. We also interviewed several …

An integrated modelling and remote sensing approach for hydrological study in arid and semi-arid regions: the SUDMED Program

2008

International audience; Recent efforts have been concentrated in the development of models to understand and predict the impact of environmental changes on hydrological cycle and water resources in arid and semi-arid regions. In this context, remote sensing data have been widely used to initialize, to force, or to control the simulations of these models. However, for several reasons, including the difficulty in establishing relationships between observational and model variables, the potential offered by satellite data has not been fully used. As a matter of fact, a few hydrological studies that use remote sensing data emanating from different sources (sensors, platforms) have been performe…

Modélisation numérique d'assemblages collés : application à la réparation de structures en composites

2013

This study is one part of a program of research with regard to the repair of composite structure with extern bonded-patches. The principal objectives of this program are, on one side, the identification of all the factors susceptible to influence the long-term performance of this type of repair, on the other, to determine the extent to which the use of such assemblage can be proved to be an optimal solution. The conception of such a system needs essentially the development of a tool of simulation and of robust prediction because various mechanisms of damage can take place in a very complex way and the final fracture of the system arise from the propagation of damage zones. This study consis…