Search results for "zones"
showing 10 items of 107 documents
Zones humides
2018
International audience
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 …
Cargamentos de conservas de pescado béticas en el Mediterráneo Occidental durante la época Julio-Claudia
2023
A lo largo del Alto Imperio, la ciudad de Roma cuenta con aproximadamente un millón de habitantes, población que no igualará ninguna otra ciudad europea hasta el Londres del siglo XVIII, ni ninguna otra ciudad mediterránea hasta el Estambul del siglo XX. Con el fin de preservar su estabilidad, el Estado ha de atender tanto a las necesidades alimenticias de la megalópolis, como a las de las de las legiones diseminadas en las fronteras del Imperio. En este contexto, las provincias romanas como la Bética (actual Andalucía grosso modo) contribuyeron al aprovisionamiento alimenticio de la plebs y el ejército, implicando en ello numerosos barcos para la rápida y eficiente exportación de sus biene…
A novel mixed valent Cu(II)-Cu(I) 2D framework made of a hydrazone and μ-SCN bridged metallacyclic loops cross-linked by μ3-SCN chains.
2012
A mixed valent copper complex [Cu(II)Cu(I)(L)(μ-SCN)(μ(3)-SCN)](n) (LH = N'-((pyridin-2-yl)methylene)acetohydrazide) has been synthesized and characterized. It is a unique example of a 2D mixed valent Cu(II)-Cu(I) interlinked molecular assembly with a very unusual bridging property of the hydrazone ligand. An extraordinary in situ partial Cu(II)→ Cu(I) reduction is observed in this system at room temperature.
Oxidative cyclization of aldehyde thiosemicarbazones induced by potassium ferricyanide and by tris(p-bromophenyl)amino hexachloroantimoniate. A joint…
2005
The oxidative ring closure reaction of some aryl-substituted thiosemicarbazones induced by "bona fide" one-electron abstracting agents was investigated, by means of both experimental and computational techniques. The corresponding 1,2,4-triazole derivatives were the only cyclization products observed. The occurrence of two slightly different mechanistic pathways for the reaction is discussed.
Comparative environmental analysis of soil sampling methods in precision agriculture for lime application in Paraná State, Brazil
2020
Precision agriculture (PA) provides techniques that favour the localized application of inputs allowing their rational use. This makes the PA a potential indicator of reduced operational costs, input volume, and environmental impacts. The objective of this study was to evaluate and compare the environmental effects of three different sampling methods used in PA for the lime application. The first sampling method evaluated was the grid sampling (GS). It was performed at a density of one sample per hectare in a 100×100 m georeferenced grid. The second method was the directed sampling, that was performed after defining the management zones by soil apparent electrical conductivity (ECa) using a…
Zones d'ammonites et de foraminifères du Vraconnien au Turonien : Une comparasion entre les domaines boréal et téthysien (NW Europe / Tunisie central…
2008
International audience; Depuis la fin du 19ème siècle, l'intervalle comprenant l'Albien supérieur élevé, le Cénomanien, le Turonien et le Coniacien basal a été subdivisé d'abord en zones d'ammonites puis, à partir du milieu du 20ème siècle, en zones de foraminifères planctoniques, deux groupes de macro- et de microfossiles particulièrement efficaces en bio-chronostratigraphie grâce à leur taux d'évolution rapide. Toutefois, des différences de compositions fauniques entre le domaine boréal (Europe du Nord-Ouest) et le domaine téthysien (Méditerranée) ont longtemps empêché des corrélations précises entre ces deux domaines. Aujourd'hui, dans un intervalle de temps couvrant environ 16 millions …
Ārvalstu tiešo investīciju piesaiste Uzbekistānai
2018
Bakalaura darba tēma ir Ārvalstu tiešo investīciju piesaiste Uzbekistānā. Bakalaura darba mērķis ir sistematizēt teorētiskos uzskatus un praktiskos pasākumus ārvalstu tiešo investīciju piesaistīšanai un identificēt investīcijām labvēlīgu vidi vietējā tautsaimniecībā ekonomiskās modernizācijas ietvaros. Darba pirmā, teorētiskā, daļa satur izpēti, pamatojoties uz ārvalstu tiešo investīciju piesaisti un stimulus ārvalstu tiešo investīciju piesaistei. Darba otrajā daļā tiek definētas ārvalstu tiešās investīcijas Uzbekistānā, galvenokārt no Uzbekistānas Republikas tiesību regulējuma par ārvalstu investīciju atvieglojumiem, kas paredzēti ārvalstu investoriem Uzbekistānā un ārvalstu tiešo investīc…
The Boulton-Katritzky Reaction: A Kinetic Study of the Effect of 5-Nitrogen Substituents on the Rearrangement of Some (Z)-phenylhydrazones of 3-Benzo…
2014
The kinetics of the ring-into-ring conversion of some new (Z)-phenylhydrazones of 3-benzoyl-1,2,4-oxadiazole containing different nitrogen-substituents at C-5 (3b-d; X = NHMe, NMe2, and NHCOMe) into the relevant triazoles 4b-d have been examined in a wide range of pS+ (0.1-11.9) in 1:1 (v/v) dioxane/water solution. The obtained results have been compared with previous data concerning the (Z)-phenyl-hydrazone of 5-amino-3-benzoyl-1,2,4-oxadiazole (3a; X = NH2). All of the studied (Z)-phenylhydrazones rearrange through three different pathways (specific acid-catalysed, uncatalysed and general base-catalysed). The different effects of the substituents on the course of the rearrangement in the …
The formation of dominant voice in issue arenas
2011
Abstract The aim of the present study was to map out required changes to current stakeholder thinking in public relations (PR) research and practice for a better suited model for PR professionals. The concept of issue arenas (Luoma-aho & Vos 2009) was adopted for the future direction of stakeholder thinking. Further, a central aspect of PR management on issue arenas is the division of voice – or indirect power – of different players. It was suggested that gaining a dominant voice in an issue arena would facilitate the attainment of organizational goals. Meaning was considered cental in this process. This thesis, focused, on the formation of dominant voice in issue arenas. Two research quest…