Search results for "Modelling"
showing 10 items of 1353 documents
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…
A virtual spreader to overcome experimental limits: Example of use to deepen the meaning of the transverse coefficient of variation
2017
International audience; A virtual spreader was modelled by combining the use of theoretical motion equations and statistical distributions of input parameters. These parameters were deduced from experimental measurements using a custom-made spreader, an imaging system, a particle impact recording device and a rotating test bench. Using this model, each spread pattern was computed using a random selection of values following the statistical distribution of each input parameter. Using simulations, we quantified how the CV value was affected by application rates and measurement protocols whatever spreader settings. Simulations showed the CV value and its measurement variability increased when …
Study and modelling of the impacts of agricultural practices on the abundance of soil microbial communities: dynamics at the landscape scale
2022
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 in the agricultural sector. The goal of this thesis was to characterize spatial and temporal dynamics of soil microbialcommunities 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. For this, a multi-disciplinary approach was used combining microbial ecology, environment assessment, spatial computer modeling, associated to a participatory app…
SCIT modelling : Conception of questionnaire
2010
International audience