Search results for "Variations"
showing 10 items of 129 documents
Texte, texture, textile. Variations sur le tissage dans la musique, les arts plastiques et la littérature
2013
International audience
Macro-elements in the mixed boundary value problems
2000
The symmetric Galerkin boundary element method (SGBEM), applied to elastostatic problems, is employed in defining a model with BE macro-elements. The model is governed by symmetric operators and it is characterized by a small number of independent variables upon the interface between the macro-elements.
Profiles and seasonal distribution of airborne fungi in indoor and outdoor environments at a French hospital
2009
International audience; A one-year prospective survey of fungal air contamination was conducted in outdoor air and inside two haematological units of a French hospital. Air was sampled with a portable Air System Impactor. During this period of survey, the mean viable fungal load was 122.1 cfu/m(3) in outdoor air samples, and 4.1 and 3.9 cfu/m(3) in samples from adult and pediatric haematology units, respectively. In outdoor samples, Cladosporium was the dominant genus (55%) while in the clinical units, Penicillium sp. (23 to 25%), Aspergillus sp. (15 to 23%) and Bjerkandera adusta (11 to 13%) were the most frequently recovered airborne fungi. The outdoor fungal load was far higher in autumn…
North-Atlantic Oscillation and regional-scale sea-surge variability in Gulf of Lions during the 20th century
2010
Article soumis; International audience; Sea-surge variations recorded at three tide-gauge stations (Grau-de-la-Dent, Sète, and Port-Vendres) around the Gulf of Lions (Northwest Mediterranean Sea) are mostly locally forced by onshore winds blowing from 90° to 180° related to an atmospheric depression usually centered between the Bay of Biscay and the British Island, which is more prevalent during the negative phase of the North-Atlantic Oscillation (NAO). During the second half of the 20th century, the long-term increase of sea-surge height at Grau-de-la-Dent finds no counterpart in the positive deviation of the NAO. The relationship between the monthly frequency of sea surges > 20 cm at Gra…
Functional ecology for evaluating and predicting the aptitude of permanent grassland to provide services
2013
National audience; Applying the principles of functional ecology helps better predict the services which can be provided by permanent grassland. Farming practices and environmental characteristics influence the functional composition of grassland. Functional plant types have a generic effect on forage services which can be assessed. 13 types of grassland composed of distinct functional types were defined based on 1,283 sample grassland fields located on 8 sites. This approach was validated by checking 8 Ellenberg indicator values (used to evaluate environmental characteristics and farming practices) against climatic data and descriptive data for farming practices. The interest of a function…
Temporal dynamics of arable weeds communities assembly : interactions between farming practices and ecological processes across crop sequences
2018
Understanding how farming practices affect weed community assembly in arable fields is a core challenge of agro-ecology. Weeds are supposed to share particular ecological characteristics that allow them to colonize arable fields despite environmental constrains exert by farming practices. In addition, interactions between ecological processes operating during a cropping season (eg: abiotic filtering) and at the scale of crop succession (eg: temporal dispersal) are supposed to drive weed community assembly in arable fields. These two hypotheses have been tested in my phD work.First, we compared a pool of weed species to a pool of non-weed herbaceous plants based on several functional traits …
Dissolved silica in the Garonne River waters : changes in the weathering dynamics
2000
The major ion chemistry of the Garonne River is indicative of seasonal variations in the weathering dynamics of the drainage basin. Using the geochemical model MEGA for calculation of the contribution of atmospheric CO2 to the total bicarbonate fluxes exported by the Garonne River allows estimations of the concentrations of the major dissolved elements that originate from silicate- and carbonate-rock weathering. The molecular ratio SiO2/Al2O3 was calculated for the 1989–1992 period to identify the main type of weathering in the Garonne River, and montmorillonite was shown to be the major mineral occurring in the weathering products. The seasonal variations of the SiO2/Al2O3 ratio also showe…
A la découverte des odeurs
2019
Often taken for granted, the sense of smell has seldom been discussed or understood. However, since the start of the 20th Century, studies in this area have grown exponentially and today there is a greater understanding of the olfactory system – at both structural and functional levels. Scientists now concern themselves with questions about the holistic nature of our sense of smell and are investigating the role of odors in interpersonal relations, in food intake processes, in the diagnosis of certain illnesses, and many other areas. The beginnings of this knowledge are as fascinating as they are abundant and numerous disciplines are involved: psychology, physiology, genetics, neuroscience,…
Gestion du pâturage au printemps en système bovin allaitant : diversité des pratiques en Saône-et-Loire
2009
National audience; Grazed grass is the cheapest forage for making meat'. In order to incite farmers to make their forage systems more self-sufficient and thrifty, the 'Chambre d'Agriculture de Saone-et-Loire' (a professional agricultural organization for that departement) has been monitoring for five years the management of spring grazing on 23 farms. The analysis of farmers' practices lead to considerations as to put to the best use the grazed grass, according to the pedo-climatic conditions and the constraints of the farms. With the aim of optimizing the pasture resources in order to limit the purchase of concentrates and to cope with the climatic hazards, the study of the management of s…
Effets du cuivre sur quelques indicateurs de la qualité biologique des sols viticoles. Etude à différentes échelles
2008
Des produits à base de cuivre sont utilisés depuis plus d’un siècle en viticulture pour lutter contre le mildiou (et d’autres maladies). Cet élément s’accumule dans le sol, où il peut atteindre des concentrations importantes, susceptibles d’en altérer le fonctionnement biologique. Bien que potentiellement dangereux pour la biocénose des sols, le cuivre est toujours utilisé, notamment en Agriculture Biologique. Dans ce travail, nous avons cherché à préciser les impacts du cuivre sur quelques aspects de la qualité biologique des sols viticoles en conditions « réelles », à court, moyen et long terme. Les effets à long terme ont été appréciés à l’échelle d’une région viticole (la Champagne) à t…