Search results for "impact"

Evaluation agroécologique de systèmes de culture en zone tropicale humide : Cas de la mise en valeur agricole d'une savane herbacée acide (Plaine des…

2013

Dans les régions tropicales humides, concilier intensification agricole et protection des ressources naturelles est un défi majeur et difficile à relever. Dans les savanes acides du nord-est laotien, des systèmes de culture de semis direct sur couverture végétale (SCV), basés sur les trois principes du non-labour, d’une couverture permanente du sol, et sur la pratique de rotations culturales diversifiées, sont proposés comme alternative technique à l’intensification agricole conventionnelle basée sur le labour. Si ces systèmes ont connu une diffusion importante et rapide dans les grandes agricultures mécanisées, leur diffusion reste néanmoins à ce jour limitée en contexte de petite agricult…

Holocene fire activity during low-natural flammability periods reveals scale-dependent cultural human-fire relationships in Europe

2018

Abstract Fire is a natural component of global biogeochemical cycles and closely related to changes in human land use. Whereas climate-fuel relationships seem to drive both global and subcontinental fire regimes, human-induced fires are prominent mainly on a local scale. Furthermore, the basic assumption that relates humans and fire regimes in terms of population densities, suggesting that few human-induced fires should occur in periods and areas of low population density, is currently debated. Here, we analyze human-fire relationships throughout the Holocene and discuss how and to what extent human-driven fires affected the landscape transformation in the Central European Lowlands (CEL). W…

A theoretical study of the wet removal of atmospheric pollutants. Part I: the redistribution of aerosol particles captured through nucleation and imp…

1985

Abstract A theoretical model is formulated which allows the processes that control the wet deposition of atmospheric pollutants to be included in cloud dynamic models. The model considers the condensation process and the collision-coalescence process which, coupled together, control the fate of atmospheric aerosol particles removed by clouds and precipitation through nucleation scavenging and impaction scavenging. The model was tested by substituting a simple parcel model for the dynamic framework. In this form the model was used to determine the time evolution of the aerosol particle mass scavenged by drops as well as the aerosol particle mass left unactivated in air as “drop-interstitial”…

Climats tropicaux d'aujourd'hui à demain : variabilité et changements

2008

Present and future tropical climates : their climate variability and their climate changes The oriffttality of tropical climates is re-examined under the light of climate variability and climate change, both present and future . The interannual variability of rainfall is on average larger in the tropics than in the extra-tropics, but it is also spatially more contrasted. Human communities have often responded to this constraint through efficient coping strategies. The regions showing the most variable climate do not necessarily have lower population densities, an indication that in the long run variability is not decisive. However, the recent demographic growth of these regions is often low…

Impacts sur le climat régional induits par l'immersion d'une zone aride : cas de Chott Jérid (sud de la Tunisie).

2017

This work aims to show the possible impacts on the regional climate that could be caused by the partial immersion ofChott Jérid located in the south of Tunisia. Climate simulations have been carried out using the Weather Research andForecasting (WRF) model to compare the present climate of the Chott area simulated over the period 1991-2011 under realconditions of land use to the climate simulated in the fictional presence of a vast artificial waterbody (or lake). Comparisonsshowed that the lake would have a particularly moderating effect on average air temperatures. The sensible heat flux wouldincrease substantially during the winter and decrease during the summer, while latent heat and moi…

L'arôme du cassis

2019

Overall survival impact of BEACOPP versus ABVD in advanced hodgkin lymphoma: a pooled analysis of 4 randomized trials

2016

IF 6.671; International audience

Symbiose fixatrice de l'azote des légumineuses : principes de fonctionnement, impacts agronomiques et environnementaux

2017

National audience

Très longs épisodes secs hivernaux dans le bassin méditerranéen : variabilité spatio-temporelle et impact sur la production céréalière en Espagne.

2018

This study concerns the long winter sequences without rain at the whole Mediterraneanbasin scale. Objectives are (i) to define theses extreme events as geographical and climatological objectscharacterized by a location, a spatial extension and a temporal length and (ii) measured impacts of these eventson the cereal production in Spain. 76 events of very long dry spells (eVLDS) are detected over the 1957-2013period. These eVLDS are grouped into 4 typical recurrent configurations at the Mediterranean basin scale: North-East, West, Scattered & Localised and South-East. The eVLDS have a greater impact on barley, wheat and oatyields (winter crops grown through rainfed agriculture) than rainfall …

Cropping system dynamics, climate variability, and seed losses among East African smallholder farmers: a retrospective survey.

2014

Abstract Climate variability directly affects traditional low input and rain-fed farming systems, but few studies have paid attention retrospectively to the cropping system’s ability to mitigate climate risk. This study analyzes the impacts of rainfall variability on farmers’ seed variety losses over time, considering changes in smallholder farming systems. The cropping system dynamics, in favoring maize at the expense of sorghum and pearl millet, have induced an increasing risk of seed loss during drought. Combining ecological anthropology and climatology, a retrospective survey asking farmers about the period 1961–2006 was carried out at three altitudinal levels (750, 950, and 1100 m) on …