The Journalistic Touch

Jean Ary describes opportunities in the home economics writing field

Legend Echoes In Chimes Of Christmas

Jean Ary interprets the songs of holiday bells with yesterday\u27s folk lore

Spring Sports in the Spotlight

Whether it\u27s bowling on the green or golfing, Jean Ary takes you out to play

Discover Your Jewelry Personality

jean Ary advises careful design planning in costume ornament

Pet Peeves Come Out From Behind the Desks

Eleanor White speaks up for the teachers in their criticisms of student behavior. Jean Ary retaliates on behalf of the student

La matière organique des sols (MOS) : un héritage difficile mais fructueux

Interface entre géosphère et biosphère, les sols doivent, de manière immédiatement perceptible, la MO qu'ils renferment aux végétaux, voire aux animaux qu'ils supportent et/ou abritent. La présence de MO au sein des sols et son importance sont connues de longue date. Cette importance a même été très exagérée avec la théorie de l'humus qui, vers la fin du 18edébut du 19e siècle, supposait que les végétaux tiraient de ce substrat toutes leurs substances nutritives, carbone compris. En 1840, dans son traité « la chimie organique et son application en agriculture et en physiologie », Liebig rejette cette théorie et promeut des concepts plus proches de la réalité. Ramenée à une place plus modeste, la MOS est cependant bien prise en compte lors de l'invention de la pédologie moderne, attribuée au géologue russe Dokouchaev, à la fin du 19e siècle. Dépêché en Ukraine en 1877, pour en étudier les sols, Dokouchaev a fondé la reconnaissance, dans les profils qu'il y a étudiés (des chernozems), de trois horizons superposés se distinguant avant tout de bas en haut, par leur richesse en matière organique

Policy Mix Coherence: What Does it Mean for Monetary Policy in West Africa?

This article examines the influence of Policy Mix coherence in Economic Community of West African States (ECOWAS). The paper innovates in two ways. First, through an interaction between the monetary conditions index and the primary structural fiscal balance, we highlight coherence-type complementarities between monetary policy and fiscal policy with regard to their effects on economic activity. Second, we show that the influence of the coherence of policy mix on the effect of monetary policy is different according to the stance of the economy within the four possible regimes of policy mix, mostly in the WAEMU subsample, where integration is deeper than in the non-WAEMU countries, thanks to the common currency (the Franc CFA) they share. The analysis is based upon a panel dataset from 1990 to 2006 and remains robust to alternative specifications used to calculate the monetary conditions index. Our results contribute to the debate regarding the prospect of an ECOWAS-wide common currency. Indeed, given the heterogeneity in the economic structure of its members States, more policy mix coherence seems necessary to avoid unexpected impacts of monetary policy on economic activity

Stock de carbone organique dans des sols de la région aride de Coquimbo (Chili) : Conséquences de l'intensité du pâturage sur des parcours par des chèvres

International audienceRésumé Les stocks de carbone organique ont été étudiés sous deux intensités de pâturage sur parcours par des chèvres et comparés à une situation témoin au sein de la station expérimentale de Las Cardas (région de Coquimbo, Chili). Les résultats montrent que sous pâturage d'intensité modérée (6 UPR ha-1 an-1), le stock de carbone organique de 0 à 100 cm de profondeur est peu affecté avec 24,3 à 29,3 Mg*ha-1 de carbone organique total contre 31,1 à 42,6 Mg*ha-1 sous végétation naturelle, ces stocks n'étant pas significativement différents (P=0,95) en raison de la variabilité des résultats entre les répétitions. En revanche, sous parcours d'intensité élevée (10 UPR ha-1 an-1), le stock de carbone organique n'est plus que de 10,2 à 15,5 Mg*ha-1. Enfin, dans ces milieux où il est particulièrement difficile d'étudier les stocks de carbone en raison de la charge souvent élevée en éléments grossiers, nos résultats indiquent qu'il est possible de prédire le stock total du carbone organique des sols à partir de la seule mesure du stock de carbone dans les 30 premiers centimètres (R2 = 0,89) avec un biais <0,1 Mg*ha-1 et une précision de 3,6 Mg*ha-1

Mapping soil water holding capacity over large areas to predict the potential production of forest stands

International audienceEcological studies need environmental descriptors to establish the response of species or communities to ecological conditions. Soil water resource is an important factor but is poorly used by plant ecologists because of the lack of accessible data. We explore whether a large number of plots with basic soil information collected within the framework of forest inventories allows the soil water holding capacity (SWHC) to be mapped with enough accuracy to predict tree species growth over large areas. We first compared the performance of available pedotransfer functions (PTFs) and showed significant differences in the prediction quality of SWHC between the PTFs selected. We also showed that the most efficient class PTFs and continuous PTFs compared had similar performance, but there was a significant reduction in efficiency when they were applied to soils different from those used to calibrate them. With a root mean squared error (RMSE) of 0.046 cm3 cm-3 (n = 227 horizons), we selected the Al Majou class PTFs to predict the SWHC in the soil horizons described in every plot, thus allowing 84% of SWHC variance to be explained in soils free of stone (n = 63 plots). Then, we estimated the soil water holding capacity by integrating the stone content collected at the soil pit scale (SWHC') and both the stone content at the soil pit scale and rock outcrop at the plot scale (SWHC") for the 100.307 forest plots recorded in France within the framework of forest inventories. The SWHC" values were interpolated by kriging to produce a map with 1 km² cell size, with a wider resolution leading to a decrease in map accuracy. The SWHC" given by the map ranged from 0 to 148 mm for a soil down to 1 m depth. The RMSE between map values and plot estimates was 33.9 mm, the best predictions being recorded for soils developed on marl, clay, and hollow silicate rocks, and in flat areas. Finally, the ability of SWHC' and SWHC" to predict Ecological studies need environmental descriptors to establish the response of species or communities to ecological conditions. Soil water resource is an important factor but is poorly used by plant ecologists because of the lack of accessible data. We explore whether a large number of plots with basic soil information collected within the framework of forest inventories allows the soil water holding capacity (SWHC) to be mapped with enough accuracy to predict tree species growth over large areas. We first compared the performance of available pedotransfer functions (PTFs) and showed significant differences in the prediction quality of SWHC between the PTFs selected. We also showed that the most efficient class PTFs and continuous PTFs compared had similar performance, but there was a significant reduction in efficiency when they were applied to soils different from those used to calibrate them. With a root mean squared error (RMSE) of 0.046 cm3 cm-3 (n = 227 horizons), we selected the Al Majou class PTFs to predict the SWHC in the soil horizons described in every plot, thus allowing 84% of SWHC variance to be explained in soils free of stone (n = 63 plots). Then, we estimated the soil water holding capacity by integrating the stone content collected at the soil pit scale (SWHC') and both the stone content at the soil pit scale and rock outcrop at the plot scale (SWHC") for the 100.307 forest plots recorded in France within the framework of forest inventories. The SWHC" values were interpolated by kriging to produce a map with 1 km² cell size, with a wider resolution leading to a decrease in map accuracy. The SWHC" given by the map ranged from 0 to 148 mm for a soil down to 1 m depth. The RMSE between map values and plot estimates was 33.9 mm, the best predictions being recorded for soils developed on marl, clay, and hollow silicate rocks, and in flat areas. Finally, the ability of SWHC' and SWHC" to predict height growth for Fagus sylvatica, Picea abies and Quercus petraea is discussed. We show a much better predictive ability for SWHC" compared to SWHC'. The values of SWHC" extracted from the map were significantly related to tree height growth. They explained 10.7% of the height growth index variance for Fagus sylvatica (n = 866), 14.1% for Quercus petraea (n = 877) and 10.3% for Picea abies (n = 2067). The proportions of variance accounted by SWHC" were close to those recorded with SWHC" values estimated from the plots (11.5, 11.7, and 18.6% for Fagus sylvatica, Quercus petraea and Picea abies, respectively). We conclude that SWHC" can be mapped using basic soil parameters collected from plots, the predictive ability of the map and of data derived from the plot being close. Thus, the map could be used just as well for small areas as for large areas, directly or indirectly through water balance indices, to predict forest growth and thus production, today or in the future, in the context of an increasing drought period linked to a global change of climatic conditions

Les effets non linéaires de la politique budgétaire : le cas de l’Union Economique et Monétaire Ouest Africaine

Les pays de l’UEMOA ont adopté, en 1999, un pacte de convergence, de stabilité, de croissance et de solidarité. Le but premier du pacte est d’imposer des contraintes aux politiques budgétaires nationales de manière à préserver la crédibilité et la convertibilité de la monnaie commune. Or, les efforts budgétaires consentis par les états peuvent être contre-productifs en entraînant l’économie dans une récession par la mise en jeu des multiplicateurs keynésiens. Cependant, il peut exister des non-linéarités dans la relation entre la politique budgétaire et l’activité économique. L’’objectif de cette communication est de tester un modèle dans lequel les effets de la politique budgétaire sont conditionnels au taux d’endettement public externe. En appliquant la logique de modélisation des seuils endogènes, initialement développée par Hansen (1996), il apparaît que jusqu’à un taux d’endettement de 83%, l’Etat exerce une influence de type keynésien sur l’activité économique et au-delà, non-keynésien voire anti-keynésien.