Documents found
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222.More information
ABSTRACTIn the Blue Ridge and Piedmont foothills of central Virginia, a widespread weathering mantle has developed in granitoid rocks. It thins out towards higher elevations but may reach values of at least 7 m at footslopes. The weathering front is irregular, limiting residuum pockets of sandy saprolite, corestones, and loamy sand nonsaprolite residuum. Kaolinite and halloysite are dominant secondary minerals in the clay fraction. DTG analysis of whole-residuum and whole-soil samples shows that 1/1 phyllosilicate contents increase upwards from saprolite to nonsaprolite residuum and to soil profiles, reaching 37 % in Bt horizons of some Ultisols. Gibbsite is a significant constituent in several profiles. In soil horizons, Al-vermiculite and Al-mica-vermiculite are major clay minerals, indicating that present pedogenetic processes are that of an acid brunification. Bulk geochemical evolution is characterized by a sharp early loss of bases, moderate depletion in Si and concomitant enrichment in Al and Fe. The residuum cover has been eroded in its upper part and is sometimes covered by thin colluvium deposits at footslopes. Inceptisols and Ultisols have developed upon both residuum and colluvium. Their present spatial distribution is related to a regional destabilization of slopes to be correlated with the last glacial maximum. Age of part of the residuum has been estimated to be at least Sangamonian. More work has to be done to accurately define the age of the weathering mantle and the environmental conditions associated with its development.
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224.More information
River restoration paradigm takes a major place in French current management of water and aquatic environments. The paradigm signifiance becames more complex for the late 1970s and its first scientific and operational occurrences. Interest for restoration has not declined but its objectives are still discussed. Especially, meanings of restoration, rehabilitation and renaturation concepts also changed without clear established definitions and practices. Focused on French Water Agencies (FWA) Loire-Bretagne, Rhin-Meuse and Rhône-Méditerranée-Corse, this research is a retrospective study of intervention policies in the field of river restoration. Main objective of the research is to highlight geographical and historical differences in definitions and practices of river restoration in French public policies. The research is based on qualitative analysis of Intervention Programs on these basins (1964-2018). In addition to this analysis we performed a quantitative content analysis of financial aids granted by the FWA to achieve river restorations (1997-2011). The results underline a tension between hydraulic and ecological conceptions of restoration. This tension is still real despite the diversification and hybidization of practices. The present analysis of AE policy interventions can contribute to the current debate about a possible rise of river restorations in public action.
Keywords: restauration, réhabilitation, renaturation, entretien, cours d'eau, hydraulique, écologique, Agences de l'eau, politiques publiques, France, restoration, rehabilitation, renaturation, stream, hydraulic, ecological, Water Agencies, public policies, France
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225.More information
The study describes the implemented approach within the framework of a research-action dealing with interactions between socio-economical and ecological dynamics in a coastal area (Ouessant island, in the west of France). It describes how the companion modelling approach has encouraged the interdisciplinarity. The tools of the companion modelling (multi-agent model, simulations computing, role-playing game) were used to raise awareness with local people in landscape dynamics. Then they were mobilized for students to coastal issues and sustainable development. The scientific knowledge was disseminated by adapting the main research output, to local population and to young people. This was done in association with land managers and educators, and a reflective analysis the commitment of participants in these devices was undertaken. Through this experiment, most participants developed new skills related to interdisciplinarity, cooperation and communication, about the environmental management. This sudy also reveals the difficulties of appropriation of the approach by the partners. The appropriation of the stance of companion modelling seems then central at the same time to constitute a collective, but also to take up developed tools.
Keywords: modélisation d'accompagnement, éducation, interdisciplinarité, gestion environnementale, posture scientifique, companion modelling, education, interdisciplinarity research, environmental management, scientific stance
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226.More information
This article focuses on the analysis of the results from an elementary class in a mathematics pre-test and a post-test concerning the Euclidean division notion. We seek to reduce the gaps between advanced and less advanced students through the use of an anticipation group. This long-term work was completed with a small and heterogeneous group of students.
Keywords: mathématique, division euclidienne, dispositif d'anticipation, élèves moins avancés, théorie de l'action conjointe en didactique, mathematics, Euclidean division, anticipation system, less advanced students, joint action theory in didactics, matemáticas, división euclídea, dispositivo de anticipación, alumnos menos avanzados, teoría de la acción conjunta en didáctica
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227.More information
In New-Caledonia the kanak tribes of Iaai island are now precious reminders of coastal morphological changes. In the context of coastal risks, as erosion, became environmental and institutional matters increasingly integrated to the land use development, to be involved in islanders memory pertaining to landscape transition and their actual coastal landscape representation provides means of handling territory link including its sensorial and symbolic dimensions. If vision is a sens rallied by the inhabitants in order to characterize the result of erosion on landscape, therefore, smell, hear and feel are sensorial landscape evolution arguments ». This paper discusses the values assigned to the Gööny coastline and the construction process of a memory landscape that relies on memories about cultural and religious activities, on toponymy reminding the beach morphology, and on tactile memory as sand texture. In this way, we will demonstrate how sense memories of landscape reflects the link between the changes of a physical environment and societal transformations, and are relevant tools to produce development projects that engage the sensitives perceptions of residents.
Keywords: érosion, littoral, mémoire, paysage, perception, savoirs, Îles Loyauté, Nouvelle-Calédonie, erosion, coastline, memory, landscape, perception, knowledge, Loyalty Islands, New Caledonia
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229.More information
The French Conservatoire du littoral was created in 1975 to bring a balance between the building and the protection of the shores. The mission of this national public administrative agency is to buy coastal plots to protect and manage landscapes and natural habitats. Among the purchased plots, around 15% are agricultural land. But can the landscape and conservation missions of the Conservatoire du littoral cope with productive farming activities ? To manage certain habitats, the Conservatoire du littoral considers certain agricultural activities as necessary. It is the case of grasslands that require management by mowing and/or grazing. Other farming activities are sometimes tolerated or encouraged on Conservatoire du littoral lands. Contract specifications with ecological conditions are negociated with farmers to frame the practices. The article goes through the history of the preference for grasslands at the Conservatoire du littoral, while also presenting the other types of agricultural activities encountered on the agency's land. The aim is to present the series of questions and knowledge that led to the formulation and current development of the principles of action in agriculture at the Conservatoire du littoral.
Keywords: littoral, agriculture, nature, paysage, prairie, expertise naturaliste, cadrage, coastline, agriculture, nature, landscape, meadow, naturalist assessment, framing
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