Search results for "PRODUCT"
showing 10 items of 13045 documents
The importance of phytoplankton production for carbon budgets in a semiarid floodplain wetland
2011
Phytoplankton production (PP) in wetlands is not measured as often as that of macrophytes. A three year-study during a period of sustained high flooding was undertaken in a central Spanish floodplain wetland (Las Tablas de Daimiel National Park) to determine net PP, its spatial heterogeneity and controlling factors, and compare it with primary production in macrophyte communities. This enabled us to estimate carbon budgets for each community. All PP variables showed high spatial and temporal variability among sites, resulting in low coherence even when flooding connected all sites. Net PP corresponded to 25- 36% of submerged plant production and 3-10% of helophyte production. Net PP was con…
Does differential iron supply to algae affect Daphnia life history? : An ionome-wide study
2019
The availability of iron (Fe) varies considerably among diet items, as well as ecosystems. Availability of Fe has also changed due to anthropogenic environmental changes in oceanic as well as inland ecosystems. We know little about its role in the nutrition of ecologically important consumers, particularly in inland ecosystems. Physiological studies in several taxa indicate marked effects of dietary Fe on oogenesis. We predicted that differential Fe supply to algae will impact algal Fe concentration with consequences on the life history of the freshwater grazer, Daphnia magna. We found that algal Fe concentration increased with Fe supply, but did not affect algal growth, indicating that the…
Les inégalités sociales à l'école : tout n'est pas "joué" à l'école primaire
1989
International audience
L'économie matérielle de la France (1830-2015). L'histoire d'un parasite ?
2018
This article explores the long-term dynamics of material use in France over a period of 185 years. It is based on material flow accounts that are perfectly consistent with the standards of Material Flows Analysis at the national economic scale. This work - which covers domestic extraction, imports and exports - is the first long-term study of material flows for France, with annual and national data for most of the period. Our database allows us to study the evolution of French metabolism during the industrialization of the country, together with the increasing dependence on abiotic materials. We highlight a singular metabolic trajectory: that of a state that benefits from successive world-s…
L'organisation de l'université française à la lumière de ses processus de certification
1984
International audience; L'assimilation de l'école à la firme multiproduit autonomie soulève de nombreuses difficultés contextuelles. Malgré tout, l'utilisation au cas de l'établissement scolaire des outils classiques de la théorie économique de la production est susceptible de rendre compte des conséquences de ses pratiques éducatives sur un mode de fonctionnement. En faisant référence à ce cadre d'analyse, le propos de l'auteur est de révéler ici l'organisation actuelle de l'université française en examinant le rôle des divers acteurs dans le processus de production de diplômés et de vérifier, en définitive, l'existence d'un assortiment entre les établissements et leurs publics étudiants, …
Les fonctions de production de l'université : limites et développements
1999
International audience
Un compendio de Investigaciones en economia de la educacion
2012
Este artículo presenta los principales temas abordados por los economistas de la educación a lo largo de los últimos cincuenta años. Después de recordar brevemente los antecedentes de la disciplina, se describen las aportaciones teóricas y empíricas realizadas a raíz del desarrollo de la teoría del capital humano, que es el fundamento de la economía de la educación. Más allá de los trabajos que tratan de los efectos externos de la educación, el artículo repasa también las principales aportaciones efectuadas en el análisis de los sistemas de enseñanza y en la evaluación de las políticas educativas.
Performances linguistiques des enseignants et qualité d'apprentissage des élèves au primaire
2011
In a broad sense Education for All (EFA) is a hazardous Issue for to the least developed countries, and yet it adds, almost always, for these countries to provide additional difficulty for initial learning periods when majority in pupils has to assume the route from the local language to the teaching one. Besides, adapting in this context the provision of education has often done under the financial constraint. The hiring for supplementary teachers, as to reach EFA goal, less paid in comparison to their older colleagues. So now the teacher staff is consequently represented by new teachers with fewer initial education and pedagogical training, but definitely closer to the communities. The re…
Développement et caractérisation d’électrodes pour l’électrolyse alcaline de l’eau
2020
Splitting water into hydrogen and oxygen by electrolysis using electricity from intermittent ocean current, wind, or solar energies is one of the easiest and cleanest routes for high-purity hydrogen production and an effective way to store the excess electrical power without leaving any carbon footprints. The key dilemma for efficient large-scale production of hydrogen by splitting of water via the hydrogen and oxygen evolution reactions is the high overpotential required, especially for the oxygen evolution reaction. Hence, engineering highly active and stable earth-abundant oxygen evolution electrocatalysts with three-dimensional hierarchical porous architecture via facile, effective and …
Stratégies des familles et stratégies des établissements dans la genèse des inégalités sociales de carrières scolaires
1999
International audience