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Urban Landscape Structure of a Fast-Growing African City: The Case of Niamey (Niger)
No full textCombining multivariable statistics and geostatistics with landscape metrics, we attempted to quantify the spatial pattern of urbanization in the city of Niamey, Niger. Landscape metrics provided local quantification of both landscape composition and physiognomy while the Principal Component Analysis (PCA) yielded a multivariable summary of the main source of landscape metrics variation across the city. We used the variogram (geostatistics) to analyze the spatial pattern of the PCA outcomes and to characterize the associated spatial scales of variation. In Niamey, the main urban structure corresponded to a gradient ranging from highly diversified, fragmented, and both wooded and built-up areas in the city center and along the Niger River, to less green zones gathering steel-roofed houses whose density diminished towards the periphery. This concentric structure centered on the Niger River clearly reflected the history of Niamey. PCA and geostatistics provided appealing quantitative estimates of spatial patterns, scales, anisotropy and intensity of urban structures. Although these di_erent tools are known in landscape ecology, they are rarely used together. The present paper illustrates how they allow characterizing the marked spatial variation of the urban landscape of the fast-growing African city of Niamey (Niger). Such a quantification of the urban landscapes may be extremely useful for future correlative investigations in various fields of research and plannin
La question pas si bête. Pourquoi la menthe rafraîchit-elle ? Mise en ligne sur ouest-france.fr de l'article paru le 19 août 2016 dans le magazine Ouest France suite à interview.
No full textLe marché peut-il devenir une ressource pour l’ancrage territorial des productions locales ? Les enseignements des foires à thème de Corse et du Maroc
No full textLa notion de ressource spécifique s’est développée comme une alternative opérationnelle et conceptuelle à une approche fondée sur les avantages comparatifs. La construction de facteurs de production inimitables ailleurs, du fait de leur association à des entités, des savoirs et des procédés non substituables, devait, pensait-on, faire obstacle à toute standardisation.Le dispositif Indication Géographique français assurait dans cette perspective une garantie légale couplée à une légitimité locale par la responsabilité offerte aux producteurs de définir eux-mêmes les produits, les cahiers des charges et les aires de production. Au Nord comme au Sud, de nombreux exemples montrent pourtant que la spécification des ressources et des produits ne parvient pas à faire obstacle à une standardisation des procédés, pas plus qu’elle n’évite une captation de la réputation, laquelle ne sert pas mécaniquement l’ancrage des identités alimentaires. La communication prend pour objet des processus de relance de petites productions locales corses intégrées au système alimentaire traditionnel. Elle montre de quelles façons les activités marchandes et particulièrement les foires et les marchés locaux ont constitué une force d’ancrage décisive dans la relance. L’article prend appui sur les marchés de foire et du Maroc. Les deux situations fortement contrastées mettent en évidence que la construction d’une ressource spécifique ne peut se réduire aux seuls «facteurs de production». Les activités marchandes constituent un ressort majeur, bien que souvent ignorés, du processus de spécification et d’ancrage en couplant les pratiques productives aux pratiques d’usages des productions. Les cadres produits par l’économie des spécificités se trouvent ainsi augmentés par les nombreux apports de la sociologie des marchés
Accounting for consumers’ preferences in the analysis of dietary recommendations
No full textThe goal of this article is to present and demonstrate the applicability of an original method to assess the economic and health impacts of compliance with food-based recommendations. The method takes account of consumers’ preferences and the associated adoption cost in the assessment of various recommendations.
We combine an economic model of diet choice with an epidemiological model to compute the health impacts of dietary changes. To demonstrate the use of the method, we analyse the impacts of a 5% variation in the consumption of seven food groups taken separately: a 5% increase in consumption of fruits and vegetables (F&V) and milk products; and a 5% decrease in consumption of red meat, all meats, salty/sweet products, ready meals and butter/cream/cheese.
A recommendation, when adopted by consumers, generates important changes in the whole diet due to substitutions and complementarities among foods. All simulated recommendations have a positive impact on health. The F&V recommendation has the largest impact on the number of DALYs averted, but the highest adoption cost for consumers, especially for low-income consumers. Alone, the change in energy intake explains from 71% to 98% of the DALYs averted induced by a recommendation.
Small increases in recommended foods have the potential of generating relatively significant health gains. Preference-driven substitutions among foods have a major effect on simulated health outcomes and should be included in the assessment of dietary recommendations, together with the adoption cost borne by consumers
Tick bite risk as a socio-spatial representation-an exploratory study in massif central, france
No full textTicks are responsible for the largest number of transmissions of vector-borne diseases in the northern hemisphere, which makes the risk from tick bites a serious public health problem. Biological scientific research and prevention studies are important, but they have not focused on the population's perception of tick bite risk, especially at a spatial level. This exploratory article sets out to study this point through an innovative methodology involving the collection of 133 mental maps associated with a semi-structured interview and a socio-demographic questionnaire collected in the Massif Central region, France. The results show a strong link between the representation of the tick bite risk and the representation of particular landscapes. Forests appear as dangerous for the population, especially in the traditional activities of family walking or hiking. This calls into question overly anxiogenic prevention approaches that neglect the impact on practices in risk-prone spaces. It accentuates the need for localized education measure to improve knowledge about tick biology and avoid stereotypical and unnecessary negative representations associated with the environment
Nutritive value of two types of olive cake (Olea europaea l.) for growing rabbit
No full textThe nutritive value of 2 types of sun-dried olive cake (OC), extracted traditionally (COC) or with a 3-phase olive cake (TPOC), was studied for the growing rabbit. Four diets containing 10 or 20% of COC (COC10 and COC20) or of TPOC (TPOC10 and TPOC20) in substitution for a basal diet were compared to a control diet without OC (OC0). Five groups of 12 rabbits were fed one of the 5 diets ad libitum from weaning (35 d) to 46 d of age. The faecal digestibility was individually measured between 42 and 46 d of age. COC and TPOC are high fibre and lignin sources, with 707 and 787 g/kg dry matter (DM) of neutral detergent fibre, 530 and 554 g/kg DM of acid detergent fibre, 242 and 243 g/kg DM of acid detergent lignin, respectively. Replacing 20% of basal diet by COC sharply reduced (P<0.001) the digestibility of energy and crude protein from 0.67 to 0.54, but that of protein only moderately (from 0.80 to 0.76). The same effect was observed with the incorporation of 20% of TPOC. The digestible energy (DE) content of COC and TPOC were calculated by regression and were 3.24 +/- 0.41 and 2.94 +/- 0.52 MJ DE/kg DM respectively, corresponding to an apparent faecal digestibility of the gross energy of 0.14 (COC) and 0.13 (TPOC). The apparent faecal digestibility of the crude protein of COC was 7 units higher than TPOC (0.44 vs. 0.37) and the digestible protein (DP) content was 20% higher (27.9 +/- 4.2 g vs. 22.4 +/- 6 g DP/kg DM). Olive cake could be considered as a high fibre source with a low protein and energy content for the growing rabbit
Social drivers of rural forest dynamics: A multi-scale approach combining ethnography, geomatic and mental model analysis
No full textFarm forests and trees outside forests (i.e.,‘rural forests’) are key components for the sustainability of agri-
cultural landscapes. Farmers are the main managers of rural forests and their practices vary according to a range
of individual and collective factors. This diversity in management practices challenges the understanding of
landscape patterns and dynamics, in particular at local and regional scales. In this study, we combined forest
mapping over 150 years, ethnographic investigations and mental models to investigate the social drivers of rural
forests in a French case study. Results showed a stability of woodlands and groves, favored by the social or-
ganization system, i.e., a self-reliance and house-centered system. Recent tree encroachment in abandoned lands–caused by rural exodus and the intensification of agriculture–resulted in a spread of woodlands. In addition, a shift from family-based to market-oriented woodland management was observed, contributing to the homo-
genization of forest management practices. Hedgerows declined but with contrasted trends according to their
location and adjacent land uses: in-farm hedgerows that obstructed mechanization declined, whereas boundary
hedgerows that assisted in the maintenance of farmers’ estates were reinforced. Scattered trees were considered
of little interest by farmers and declined. This study achieved an understanding of rural forest patterns and
underlying social drivers. Mental models provided a basis for exploring the tradeoffs between ecosystem services
and disservices operated by farmers. They also revealed differences between scientific and farmer classifications
of trees outside forests. Mental models constitute a promising tool for reinforcing bonds between the social and
natural sciences
The role of diffusion-driven pure climb creep on the rheology of bridgmanite under lower mantle conditions
No full textThe viscosity of Earth's lower mantle is poorly constrained due to the lack of knowledge on some fundamental variables that affect the deformation behaviour of its main mineral phases. This study focuses on bridgmanite, the main lower mantle constituent, and assesses its rheology by developing an approach based on mineral physics. Following and revising the recent advances in this field, pure climb creep controlled by diffusion is identified as the key mechanism driving deformation in bridgmanite. The strain rates of this phase under lower mantle pressures, temperatures and stresses are thus calculated by constraining diffusion and implementing a creep theoretical model. The viscosity of MgSiO3 bridgmanite resulting from pure climb creep is consequently evaluated and compared with the viscosity profiles available from the literature. We show that the inferred variability of viscosity in these profiles can be fully accounted for with the chosen variables of our calculation, e. g., diffusion coefficients, vacancy concentrations and applied stresses. A refinement of these variables is advocated in order to further constrain viscosity and match the observables