Search results for "33"

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…

La gestion des betteraves adventices résistantes à un herbicide: une approche par simulation

2007

National audience; Les variétés de betteraves sucrières génétiquement modifiées (GM) résistantes à un herbicide sont, a priori, intéressantes dans des champs fortement infestés par la betterave adventice. Cependant, la montée à fleurs de ces betteraves GM peut entraîner l’apparition d’individus résistants, via la dispersion de pollen. Nous avons développé et utilisé le modèle GENESYS-Betterave pour simuler, à l’échelle d’une petite région agricole, l’impact des pratiques culturales sur la dispersion du transgène. Il permet d'identifier des stratégies pour contrôler les adventices et limiter l'apparition de populations résistantes en zone de production de betterave sucrière. L’utilisation de…

Typology of exogenous organic matters based on chemical and biochemical composition to predict potential nitrogen mineralization

2010

Our aim was to develop a typology predicting potential N availability of exogenous organic matters (EOMs) in soil based on their chemical characteristics. A database of 273 EOMs was constructed including analytical data of biochemical fractionation, organic C and N, and results of N mineralization during incubation of soil–EOM mixtures in controlled conditions. Multiple factor analysis and hierarchical classification were performed to gather EOMs with similar composition and N mineralization behavior. A typology was then defined using composition criteria to predict potential N mineralization. Six classes of EOM potential N mineralization in soil were defined, from high potential N minerali…

Administrative Capacity as a Constraint to Fiscal Decentralization. The Case of Romania and Poland

2020

This paper considers the problem of administrative capacity as one of the main requirements that the accession countries seeking EU membership had to meet, and as a prerequisite to the decentralization of their public sectors and public finances. The selected decentralization problems are analyzed using the cases of two countries: Romania and Poland. The results of a theoretical and practical evaluation of administrative capacity as a likely obstacle to fiscal decentralization are presented taking account of the different levels of decentralization in Poland and Romania. A comparative analysis of Romania and Poland shows that administrative capacity can be a constraint for fiscal decentrali…

School climate as predictor of teachers’ capacity to meet the educational needs of adopted children in Italy

2020

The current study examines the association between different components of school climate (teacher–principal and teacher–parent relationships, parents’ involvement in school activities, connection between school and the local services) and teachers’ competences and knowledge regarding the adoption experience. Participants were 573 teachers (95.7% women; mean age = 47.06, SD = 8.66, ranging between 25 and 65) residing in three Italian regions characterised by rates of international adoptions that are higher than the national average. The association between school climate and teachers’ knowledge and competences on adoption was evaluated via independent multiple logistic regression analyses. …

On the Impact of Heat Pumps Electric Load on the Power Consumption of Lampedusa

2020

The present paper reports the results of a simulation study regarding the impact of the adoption of heat pumps for domestic hot water production in the island of Lampedusa (Italy). In the study, it has been assumed to replace electric storage water heaters with heat pumps at every dwelling of the about four thousand domestic end-users of the island and, in addition, to control the heat pump operation in order to enhance some parameters that characterize the quality of the generation and distribution system of the island (power peak, energy losses and voltage drop). According to the results of the simulations, while the replacement of electric storage water heaters with heat pumps is able to…

Climate and agriculture: empirical evidence for countries and agroecological zones of the Sahel

2022

International audience; ow heterogenous is the impact of climate change across space and the type of agricultural production? In this paper, we investigate the relationship between climate change and variability, measured by temperature and rainfall, and agricultural production at the country and agroecological zone levels of the Sahel. We consider a crop production index and five cereals (maize, millet, sorghum, wheat and rice). Based on an original climate database and an agricultural production function estimated for the period 1961–2016, we show that average rainfall and temperature during the growing season indeed have highly heterogeneous effects on agricultural production, depending …

Air Transportation and Regional Growth: Which Way Does the Causality Run?

2013

The role of airports has become increasingly important with globalization. To have a regional airport is an especially important asset for retaining companies in the region as well as attracting new economic activity to the region. A well-developed transport infrastructure can be seen as a facilitator that allows the economic potential of a region to be realized. The provision of transportation does not, however, automatically lead to economic growth. It may also be the other way round: economic development leads to the better transport infrastructure and accessibility, stressing demand side elements. This paper aims to shed further light on the relationship between regional airports and ec…

Trattamento chirurgico dell'alluce valgo: osteotomia distale percutanea sec. Bosch (PDO) e scarf osteotomy a confronto

2016

Enrichment of amino acids by supported liquid membrane extraction using Aliquat 336 as a carrier

1998

Abstract The possible application of Aliquat 336 (trioctylmethyl ammonium chloride) as a carrier for liquid membrane extraction of amino acids was investigated. The extraction is performed from an aqueous donor phase with pH > 11 to an acceptor phase containing a salt solution through a supported liquid membrane with Aliquat 336 as a carrier in the membrane to facilitate amino acid transport. Counter-coupled transport of chloride anions from the acceptor phase to the donor phase is the driving force of the mass transfer in this system. The extraction efficiency depends on the donor phase pH, the carrier concentration in the liquid membrane, the composition of the acceptor phase and the hydr…