Search results for "wage"
showing 10 items of 731 documents
Ultrafiltration as a Means to Investigate Copper Resistance Mechanisms in Soil Bacteria
1999
Copper is a trace element of major concern for agricultural soils. It exhibits a high toxicity against microorganisms and is widely introduced into soils as a component of pesticide treatments or urban wastes such as sewage sludges or refuse composts. In most French vineyards, “Bordeaux mixture” (copper sulfate) has been applied for more than a century, sometimes leading to copper concentrations in soils much higher than the threshold values (100 mg kg−1 in France). Microorganisms exposed to high concentrations of copper or other trace elements are known to develop resistance mechanisms and represent a suitable material for the study of such processes, both at a physiological and molecular …
Copper Dynamics and Impact on Microbial Communities in Soils of Variable Organic Status
2008
International audience; The effect of soil organic status on copper impact was investigated by means of a microcosm study carried out on a vineyard soil that had been amended with varying types of organic matter during a previous long-term field experiment. Soil microcosms were contaminated at 250 mg Cu kg−1 and incubated for 35 days. Copper distribution and dynamics were assessed in the solid matrix by a sequential extraction procedure and in the soil solution by measuring total and free exchangeable copper concentrations. Copper bioavailability was also measured with a whole-cell biosensor. Modifications of microbial communities were assessed by means of biomass-C measurements and charact…
Modelling hydrolysis: Simultaneous versus sequential biodegradation of the hydrolysable fractions
2018
Hydrolysis is considered the limiting step during solid waste anaerobic digestion (including co-digestion of sludge and biosolids). Mechanisms of hydrolysis are mechanistically not well understood with detrimental impact on model predictive capability. The common approach to multiple substrates is to consider simultaneous degradation of the substrates. This may not have the capacity to separate the different kinetics. Sequential degradation of substrates is theoretically supported by microbial capacity and the composite nature of substrates (bioaccessibility concept). However, this has not been experimentally assessed. Sequential chemical fractionation has been successfully used to define i…
Soil DNA evidence for altered microbial diversity after long-term application of municipal wastewater
2010
International audience; Water resources constitute a social, agricultural and economic problem in most countries of the southern Mediterranean Basin. Alternative strategies have been developed such as the reuse of municipal wastewater for irrigation in agriculture. Despite numerous advantages for soil fertility and crop productivity, recycling wastewater in soils also has several ecotoxicological and sanitary problems. Few investigations have assessed the risk by evaluating the impact of wastewater irrigation on soil microbes. Here, we report for the first time the short- and long-term effects of treated municipal wastewater irrigation on the density and genetic structure of bacterial and f…
Schooling Effects and Earnings of French UniversityGraduates : School Quality Matters, but Choice ofDisciplines Matters More
2009
09022 - Actes sur CD-ROM; Our aim in this article is to study the relation between earnings of French universities graduates and some characteristics of their universities. We exploit data from the Céreq's "Génération 98" survey, enriched with information on university characteristics primarily from the ANETES (yearbook of French institutions of higher education). We employ multilevel modeling, enabling us to take advantage of the natural hierarchy in our separate datasets, and thus to identify, and even to measure potential effcts of institutional quality. Since we take into account many individual students characteristics, we are able to obtain an income hierarchy among the diffrent disci…
Housekeepers in French Hotels : Cinderella in the Shadows (Chapter 5)
2008
08018. Introduction by Robert Solow
Economic Returns to Education in France: OLS and Instrumental Variable Estimations
2013
En ligne sur : http://121.52.153.179/JOURNAL/LJE%20VOL%2018-2/Bhatti,%20Bourdon%20and%20Aslam.pdf; International audience; This article estimates the economic returns to schooling as well as analyzing other explanatory factors for the French labor market. It addresses the issue of endogeneity bias and proposes two new instruments for use in the instrumental variable two-stage least squares technique. Our results show that the proposed instruments are relevant and adequate, based on evidence from the available literature. After using the proposed instruments, we find that the OLS coefficients for schooling are biased downwards. Finally, we choose between the two proposed instruments.
Housekeepers lost in the Land of Labor Market Segmentation
2007
07022 - 13 p.; This communication analyses the role that the main social actors, employers, trade unions and the French government play in labour market regulations, especially in working conditions, for feminine low wage workers. Labor market segmentation and the dual market theory (Doeringer and Piore, 1971), with on one hand qualified workers employed in attractive and stable positions, and on the other hand manpower in low-paid and insecure jobs, often in back-breaking working conditions, are not new. However, they have recently reappeared in the situation of housekeepers in the French hotel industry, where there are particularly few chances of career ladders, and on the contrary, there…
Quantification of land-atmosphere exchanges of water, energy and carbon dioxide in space and time over the heterogeneous Barrax site
2008
International audience; To advance our understanding of land-atmosphere exchanges of water, energy and carbon dioxide (CO2) in space and time over heterogeneous land surfaces, two intensive field campaigns were carried out at the Barrax agricultural test site in Spain during 12-21 July 2004 (SPARC 2004) and 8-14 July 2005 (SEN2FLEX 2005) involving multiple field, satellite and airborne instruments for characterizing the state of the atmosphere, the vegetation and the soil from the visible to the microwave range of the spectrum. Part of the experimental area is a core site of area 25 km2, within which numerous crops are grown, on both irrigated and dry land, alongside fields of bare soil. Th…