Search results for "Modelli"
showing 10 items of 1866 documents
Macroecology of Southern Ocean echinoids : distribution, biogeography and modelisation
2011
What are the forcing factors and main patterns of species distribution? This question is the core of macroecological issues and is of particular interest in the present context of global warming. The main objectives of this thesis were to determine the current distribution patterns of Antarctic and sub-Antarctic echinoid species at the scale of the whole Southern Ocean and to highlight the forcing factors that control them. The ecological niche modelling of 19 echinoid species showed that distribution is mainly structured in two patterns: (1) a first one represented by species that are not limited to the south of the Polar Front and distributed from the Antarctic coasts to the sub-Antarctic…
Indicators for assessing the environmental impacts of land use changes across Europe
2008
International audience; Much progress has been made in understanding future trend development over the last years. Governments and international bodies are increasingly attempting to assess ex-ante the impact of their policy proposals. In the SENSOR project, environmental sustainability is assessed by answering a set of policy relevant questions likely to affect goods and services provided by land. The answer is complex and the assessment of future options is very sensitive to scale, how far ahead in time is being considered, and whether the assessment addresses local, regional or global concerns. The relationships between components of land use and the response of environmental indicators …
Consequences of gene flow between oilseed rape and wild radish
2013
International audience; Gene flow and introgression from crops to wild species can modify the adaptive potential and weediness of arable-land plant species. It gained recent importance with the release of genetically modified (GM) crops because of the risk of transfer of herbicide-resistance genes to related weeds. It is also a permanent possibility that could have occurred in the past with any conventional variety. In order to investigate this “normal” phenomenon and its impact, we developed three approaches in the framework of the study of gene flow between oilseed rape (Brassica napus) and wild radish (Raphanus raphanistrum). First, we compared the growth and reproduction of progeny of a…
Studying and modelling soil microbial communities dynamics at a landscape scale in response to agricultural practices
2019
Soil microbial communities play a major role in soil fertility and are important as bioindicators to evaluate the impacts of agricultural practices on soils. The challenge is to promote their use in order to support / accelerate innovation by proposing to farmers the tools necessary to assess the impacts of practice modifications on the soil microbial composition before implementing and validating them. The goal of this thesis is to characterize spatial and temporal dynamics of soil microbial communities at the scale of an agricultural landscape in order to create models and propose a Decision Support Instrument (DSI) for stakeholders in the agricultural communities. This will use a multi-d…
Studying and modelling the dynamics of soil microbial communities at a landscape scale in response to agricultural practices
2019
National audience; Soil Microbial communities play a major role in soil fertility and are important as bioindicators to evaluate the impacts of agricultural practices on soils. The challenge is to promote their use in order to support / accelerate innovation by proposing to farmers the tools necessary to assess the impacts of practice modifications on the soil microbial composition before implementing and validating them. The goal of this thesis is to characterize spatial and temporal dynamics of soil microbial communities at the scale of an agricultural landscape in order to create models and propose a Decision Support Instrument (DSI) for stakeholders in the agricultural communities. This…
3D-QSAR study of ligands for two human olfactory receptors
2008
International audience; All living organisms, including human beings, are able to detect and discriminate myriads of structurally diverse odorants through their interaction with olfactory receptors (ORs) (1). It is well accepted that the perception of thousands of odors by about 380 ORs results from a combinatorial coding, in which one OR recognizes multiple odorants and different odorants are recognized by different combinations of ORs (2). In a previous study (3), the functional characterization on two human ORs, called OR1G1 (class II) and OR52D1 (class I) have been performed using 95 odorant molecules. We used these previously obtained functional data (3) to perform a molecular modellin…
Analyse des effets direct et indirect des pratiques agricoles sur les adventices et la production de blé tendre d’hiver
2016
Analysis of direct and indirect effects of farming practices on weeds and winter wheat yield. Farmers implement farming practices to maximize production by limiting biotic (e.g. weeds) and abiotic (e.g. nutrient) growth factors. Our study aimed to quantify direct and indirect (through a change of weed pressure) effects of farming practices on yield. We analysed the relationships between farming practices, weeds and yield of 152 wheat fields located in the study site of Fénay (UMR Agroécologie, Dijon) using partial least square path modelling (PLS-PM). Our results showed that farming practices had a positive direct effect on crop productivity (β = 0.32). Farming practices decreased weed pres…
Modelling Keloids Dynamics: A Brief Review and New Mathematical Perspectives
2022
The keloids are fibroproliferative disorders described by an excessive growth of fibrotic tissue, which also invades adjacent areas (beyond the original wound borders). Since these disorders are specific to humans (no other animal species naturally develop keloid-like tissue), the experimental in vivo/in vitro research has not lead to significant advances in this field. One possible approach could be to combine in vitro human models with calibrated in silico mathematical approaches (i.e., models and simulations) to generate new testable biological hypotheses related to biological mechanisms and improved treatments. Since these combined approaches do not really exist for keloid disorders, in…
Modelling the fate of pesticides in innovative cropping systems disigned to reduce the use of pesticides
2016
EAAgroSupINRAGESTAD; The objective of this work was to assess and compare the ability of three pesticide fate models (MACRO, PEARL and PRZM) to simulate the concentration in leachates of pesticides applied in different conventional and innovative cropping systems. The test of the models was based on measurements of water flows and pesticides concentrations done in two French experimental sites. The results showed that MACRO was the most efficient model to simulate the amounts of percolated water and the concentrations of pesticides used in the various cropping systems
Dormancy and longevity of soil-buried weed seeds : from examples to generalization
2012
EA SPE EcolDur GEAPSI CT3 CT1EA SPE EcolDur GEAPSI CT3 CT1; The main part of the life-cycle of weeds, especially in cultivated fields, is spent as seeds buried in the soil. Longevity and dormancy are two major traits driving weed survival and infestation in the framework of crop rotation and management. Modelling allows inference of these key processes from morpho-anatomical description of the seeds, thus avoiding long-term germination studies of buried seeds over the years. Two new sets of experimental data on two different weeds offer the opportunity to compare actual results to predicted values. This study deals with cornflower (Centaurea cyanus), a winter weed of cereals and oilseed rap…