Search results for "assemblage"
showing 10 items of 143 documents
Human Simulation and Sustainability : Ontological, Epistemological, and Ethical Reflections
2020
This article begins with a brief outline of recent advances in the application of computer modeling to sustainability research, identifying important gaps in coverage and associated limits in methodological capability, particularly in regard to taking account of the tangled human factors that are often impediments to a sustainable future. It then describes some of the ways in which a new transdisciplinary approach within &ldquo
Functionalised Imidazoporphyrins and their application in catalysis
2017
A broad series of functionalized imidazo[4,5-b]porphyrins was synthesized by the acid-catalyzed condensation of 2,3-dioxo-5,10,15,20-tetraarylchlorins with aromatic aldehydes. Both steric and electronic features of meso-aryl substituents influence on the product yield ranging from 18% to 90%.Single-crystal X-ray diffraction analysis of the structure of zinc(II) 5,10,15,20-tetramesityl-2-(4-pyridyl)-1H-imidazo[4,5-b]porphyrinate showed that this compound forms 1D coordination chains in the solid state.The post-synthetic modifications of imidazo[4,5-b]porphyrins were investigated by performing the Suzuki-Miyaura coupling reaction, preparing water-soluble imidazoporphyrins and linear/angular b…
Consequences of sown grass margin strip on weed flora
2010
The intensification of the management of weed populations, led by a potential decrease in the yield and quality of crop harvest, has largely induced their decline in arable zones across the last decades. This floristic decline in arable landscape, has induced a loss of a larger biodiversity because the presence of others organisms (birds, insects, mammals) are strongly linked with the abundance of trophic resources as weed are. To counter with this loss of biodiversity and to limit the negative impacts of farming practices on environment, numerous agri environmental schemes were launched through Europe. In France, sown grass strips were established by farmers along streams and rivers to lim…
Dynamique et assemblage des communautés adventices : Approche par modélisation statistique
2011
To develop solutions for a productive and sustainable agriculture, principles, theories, andmethods of ecology may contribute to understand the biological processes governing the agroecosystem.The present case study was based on data collected by a network of observatories of weeds covering the whole of France (‘Biovigilance Flore’) and aimed at establishing forrules governing the assemblage and dynamics of weed communities in fields grown with annual crops. We particularly studied the possible relationships between species within acommunity, as well as the relationships between communities and their environment. Analyses were based on species abundances to take account of their effect on c…
Weed communities in conservation agriculture: what really changes?
2022
Conservation agriculture (CA) has been identified as one of the farming systems likely to deliver sustainable agriculture but its effects over time on the diversity and composition of weed communities are still discussed. For ten years, different studies were carried out in in East of France in cropping system with short rotations essentially composed with winter crops. The objective of these different studies was to identify, focusing on the transition period, the changes in the composition of communities and the consequences in terms of agronomic risk in CA systems. Using networks of 100 winter wheat fields selected to encompass a gradient of years in CA (1 to 20 years), the changes that …
Colonisation des paysages agricoles par les espèces des bordures adjacentes : apports de l’approche fonctionnelle
2014
National audience; Une crainte avancée par les agriculteurs repose sur l’hypothèse qu’une gestion plus raisonnée des bordures adjacentes aux champs cultivés pourrait, par relâchement de la pression de fauche, favoriser l’entrée de nouvelles espèces, bisannuelles ou pérennes, dans les parcelles agricoles. Afin de répondre à cette interrogation, notre objectif a été de proposer un cadre conceptuel théorique associant plusieurs champs disciplinaires de l’écologie. En comparaison des études précédemment réalisées, notre apport réside en la prise en compte des traits fonctionnels favorisant la dispersion à courte et longue distance, ainsi que des traits expliquant le maintien de populations viab…
Rôle de la diversité fonctionnelle des communautés végétales sur leur résistance à l’invasion par l’Ambroisie à feuilles d’Armoise (Ambrosia artemisi…
2012
Rapport de Stage de Master 2 SPE EcolDur CT3; Master; Les invasions biologiques posent de nombreux problèmes écologiques et économiques. Il est important de déterminer les facteurs à l’origine du succès des espèces exotiques envahissantes afin de maîtriser ce phénomène. Le but de la présente étude est d’évaluer le rôle de trois caractéristiques des communautés végétales (diversité spécifique, diversité fonctionnelle et densité) sur leur résistance à l’invasion par l’ambroisie à feuilles d’armoise, Ambrosia artemisiifolia. Des assemblages artificiels de plantes fréquemment rencontrées dans les communautés envahies par l’Ambroisie ont été effectués et soumis à l’invasion par l’espèce. Trois t…
Zinc isotopes in Late Pleistocene fossil teeth from a Southeast Asian cave setting preserve paleodietary information
2020
Significance Dietary habits, especially meat consumption, represent a key aspect in the behavior and evolution of fossil hominin species. Here, we explore zinc (Zn) isotope ratios in tooth enamel of fossil mammals. We show discrimination between different trophic levels and demonstrate that Zn isotopes could prove useful in paleodietary studies of fossil hominin, or other mammalian species, to assess their consumption of animal versus plant resources. We also demonstrate the high preservation potential of pristine diet-related Zn isotope ratios, even under tropical conditions with poor collagen preservation, such as the studied depositional context in Southeast Asia. However, assessing the …
Characterization of the metal artefacts of the two craft-quarters of the roman vicus Bliesbruck (Moselle)
2014
Diese Arbeit ist ein vollständiges Studium der Metallfunde aus den zwei Handwerkervierteln von Bliesbruck (Moselle, Frankreich). Diese Funde stammen aus vierzigjahrelangen Ausgrabungen. Das Korpus besteht aus 450 Kg Metall (Eisen, Kupferlegierungen, weisse Metalle, Gold) wovon 4 200 Objekte und 22 000 Nägel. Eine Objekt- und Funktionsidentifizierung und eine typologische Nägelzahl haben es ermöglicht, die Objektverbindungen wieder zusammenzusetzen und die Daten nach verschiedenen Kriterien einander gegenüberzustellen : Metall, Lage (Viertel und Grundstück), Chronologie und Befundnummertyp. Diese Datenüberfülle und -verschiedenheit ermöglichen das Korpus nach vielartigen geographischen Maβst…
The standing of the Southern Côte-d’Or in the evolution of the early Iron Age funeral practices in Burgundy and Franche-Comté
2014
This work is a synthesis of tumuli graves in Burgundy and Franche-Comté from Hallstatt C to La Tene B periods. The objective is to characterize the funeral assemblages in Southern Côte-d’Or as well as the influences and the tendencies that went through this area during the early Iron Age. A set of comparisons shows the particularities of the Southern Côte-d’Or at several levels: the recruitment of the populations, the position and orientation of the deceased, the architecture of the graves and their internal arrangements, the typology and positions of the personals items, the nature and locations of the deposits. These various leads allow reconstituting costumes and mortuary practices, as w…