Analyse diachronique de l’efficience technique des systèmes de production bovin viande. Baisse de la productivité des facteurs variables sur 23 ans

De 1990 à 2012, les exploitations d’élevage bovins viande françaises ont accru leur taille et leur productivité du travail de plus de 60 % grâce, notamment, à une substitution travail/capital et à une simplification de certaines pratiques d’alimentation du troupeau, entre autres. L’efficience technique des systèmes de production, mesurée par le ratio volume de production hors aides/volume des consommations intermédiaires a baissé de près de 20 %, alors que le revenu par travailleur s’est maintenu grâce aux aides et aux gains de productivité physique du travail. Cette efficience technique est positivement corrélée à l’autonomie alimentaire des exploitations, elle-même négativement corrélée à la taille des exploitations et des troupeaux. Alors que le volume de production par hectare de surface agricole utilisée a stagné, l’autonomie alimentaire par les fourrages (la valorisation de l’herbe) a perdu 6 points. Les 23 années de progrès génétique, technique, technologique et des connaissances ont accompagné l’augmentation continue de la taille des exploitations et de la productivité du travail, et ont donc juste permis de compenser la diminution d’efficience des systèmes de production.Over the past 23 years (1990-2012) French beef-cattle farms had increased their size and labor productivity by more than 60%. These gains were possible thanks to a substitution work/capital and to a simplification of herd feeding practices. The efficiency of production systems is estimated by the ratio volume of agricultural production/volume of intermediate consumptions (inputs, services, capital consumption). This efficiency decreased by 20%, while income per worker remained stable thanks to aids and subsidies and to the gains in labor productivity. The efficiency of the beef-cattle farming systems is strongly positively correlated with the feed self-sufficiency, which is itself negatively correlated with the size of farms and herds. While the volume of agricultural products per hectare of agricultural area remained stable, the forage feed self-sufficient lost 6 points. 20 years of genetics, technical, technological and knowledge progress has thus helped offset lower efficiency strongly related to the continuous increase in the size of the farms

Shadow enhancers: Frequently asked questions about distributed cis ‐regulatory information and enhancer redundancy

This paper, in the form of a frequently asked questions page (FAQ), addresses outstanding questions about “shadow enhancers”, quasi‐redundant cis ‐regulatory elements, and their proposed roles in transcriptional control. Questions include: What exactly are shadow enhancers? How many genes have shadow/redundant/distributed enhancers? How redundant are these elements? What is the function of distributed enhancers? How modular are enhancers? Is it useful to study a single enhancer in isolation? In addition, a revised definition of “shadow enhancers” is proposed, and possible mechanisms of shadow enhancer function and evolution are discussed. The term “shadow enhancer” was coined rather recently and this article not only gives a revised definition of this term but also discusses possible mechanisms of shadow enhancer function and evolution.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90151/1/135_ftp.pd

Progress in the use of ionic liquids as electrolyte membranes in fuel cells

This work provides a critical review of the progress in the use of Room Temperature Ionic Liquids (RTILs) as Proton Exchange Membrane (PEM) electrolytes in Fuel Cells (FCs). It is well-known that for an efficient early commercialisation of this technology it is necessary to develop a proton exchange membrane with high proton conductivity without water dependency capable of working at temperatures above 100 °C. The use of ionic liquids as electrolytes in electrochemical devices is an emerging field due to their high conductivity, as well as their thermal, chemical and electrochemical stability under anhydrous conditions. This paper attempts to give a general overview of the state-of-the-art, identifies the key factors for future research and summarises the recent progress in the use of ionic liquids as an innovative type of PEMs.This research was supported by the Ministry of Education, Culture and Sport under the Project CTQ2012-31639 (MINECO, SPAIN-FEDER2001–2013)

Traitement et épuration biologique des eaux

Bébin Jean. Traitement et épuration biologique des eaux. In: Diplômées, n°154, 1990. Quel environnement nous prépare le génie génétique ? Séminaire AFFDU-Currier 8-9 mars 1990. pp. 156-160

Energy consumption, greenhouse gas emissions and economic performances assessments in suckler cattle farms. Impacts of the conversion to Organic Farming

International audienc

Traitement et épuration biologique des eaux

Bébin Jean. Traitement et épuration biologique des eaux. In: Diplômées, n°154, 1990. Quel environnement nous prépare le génie génétique ? Séminaire AFFDU-Currier 8-9 mars 1990. p. 238

Biological water treatment and epuration

Bébin Jean. Biological water treatment and epuration. In: Diplômées, n°154, 1990. Quel environnement nous prépare le génie génétique ? Séminaire AFFDU-Currier 8-9 mars 1990. p. 246