Origin of sulphated grey crusts on glass in polluted urban atmosphere: stained glass Windows of Tours Cathedral (France)

The grey crusts covering some places of the weathered stained glass Windows of Tours Cathedral were studied by Analytical Scanning Electron Microscopy These crusts are constituted by a gypsum cement embedding many particles: microspherules (fly ash generated by combustion processes, rounded particles of leached glass, hypersiliceous spherules from tuffeau stone); angular fragments of leached glass; organic objects; siliceous and sulphated aggregates. The particles contained in the sulphated black crusts covering the stone, in the air and in the rain in Tours were studied simultaneously and compared with those of the stained glass Windows' grey crusts. In all cases, similar kinds of fly ash are present demonstrating the action of atmospheric microparticulate pollution both on the stained glass Windows and on the stone. Furthermore, the presence of hypersiliceous particles in crusts on glass and in the rain suggests transfers from stone to glass by rainwater run-off and possibly directly from the atmosphere. The presence of leached glass in the sulphated crusts on glass leads also to conclude on the modifying of the glass surface by the action of the rainwater run-off. Moreover, calcium and sulphur needed to form superficial gypsum crusts come both from the nearby calcareous stone, from the atmospheric gases and particles, and probably partially from calcium contained in unweathered glass

Do Consumers Pay More for What They Value More? The Case of Local Milk-based Dairy Products in Senegal

Senegalese consumers prefer milk-based dairy products that are local and fresh to ones produced with imported powder. However, prices for fresh-milk-based and powder-based products are not significantly different. I address this puzzle by first confirming the preference using choice-based conjoint data to evaluate whether Senegalese consumers will pay a significant positive premium for fresh local products. I then identify price determinants using a unique dataset of milk product characteristics. The results verify the Senegalese preference for fresh local dairy products and show that consumers’ misinformation regarding product composition prevents them from allocating a higher price to local milk-based products

Intermediaries, transport costs and interlinked transactions

Farmers in developing countries often encounter difficulties selling their products on local markets. Inadequate transport infrastructure and large distances between areas of production and consumption mean that farmers find it costly to bring their produce to the market and this very often results in small net margins and poverty amongst farmers who are geographically isolated. Agriculture in developing countries is characterized by the presence of intermediaries that have a transport cost advantage over farmers. Because of their market power, these intermediaries are able to impose interlinked contracts and are free to choose a spatial pricing policy. In this paper, we develop a model of input-output interlinked contracts between a trader and geographically dispersed farmers. We analyze what the welfare implications are as well as the effect on the trader's profit of imposing the use by the trader of either uniform or mill pricing policies, as opposed to spatial discriminatory pricing. We establish under what conditions public authorities can increase farmers' income and reduce poverty in rural areas by restricting the spatial pricing policies that intermediaries can use

An intermediary’s optimal geographical expansion choice under uncertainty

High transport costs to reach markets and obtaining low prices on these markets make it difficult for small-scale farmers in developing countries to market their production. Geographically isolated farmers therefore often have to rely on intermediaries to transport and sell their output on markets. To collect output from farmers, these intermediaries have to make investments while facing uncertainty due to the volatility of agricultural prices on world markets. Using real options, we establish the optimal investment strategy for an intermediary in terms of when to invest and with how many geographically dispersed farmers to contract with. We also establish how, after the initial investment, the intermediary should optimally further expand its collection area. We determine what public authorities could do to encourage the emergence of intermediaries who collect production from isolated farmers. Finally, we apply our framework to analyze investment decisions made by intermediaries in the milk sector in Senegal

Intermediaries, transport costs and interlinked transactions

Transport costs play a key role in agricultural markets in developing countries and are one of the causes of poverty amongst farmers that are geographically isolated. Another characteristic of agricultural markets is that they often involve interlinked transactions. However, the existing theoretical literature on interlinked transactions does not take into account the existence of transport costs. This paper develops a model of input-output interlinked contracts between geographically dispersed farmers and a trader, whether this trader is for-profit or non-profit. We derive implications of imposing either uniform or mill pricing policies, as opposed to spatial price discrimination. Impact on profit, farmers' income, level of production, social welfare and regional disparities are investigated.Rural development; spatial pricing; transportation

Évaluation de la performance d'un outil d'assurance qualité des protocoles institutionnels

Objectif : L'objectif de cette étude est d'évaluer la performance d'un outil sur l'amélioration de la qualité des protocoles promus par les centres hospitaliers universitaires (CHU). Méthodes : Une étude prospective, en groupes parallèles, contrôlée, avec randomisation collective, a été conduite au sein des directions de recherche clinique (DRC) pendant quatre mois. Soixante-quatre protocoles ont été analysés. Résultats : Avant intervention, il n'existait aucune différence significative des scores qualité entre les groupes intervention et contrôle. Entre les deux périodes, le score méthodologique et réglementaire s'est amélioré significativement (81,7 ± 13,7 vs 90,4 ± 9,2 ; p = 0,040) dans les DRC intervention uniquement. La différence d'évolution des deux groupes n'a pas été significative dans le modèle d'analyse de variance (p = 0,501). Conclusion : Dans une observation limitée à 12 CHU, la qualité des protocoles promus a été jugée sous-optimale et perfectible. L'implication des DRC dans une démarche assurance qualité, telle que cette étude, a amélioré "spontanément" celle-ci. L'application systématique de notre outil n'a pas amélioré significativement le résultat

Relationship between the composition of the intestinal microbiota and the tracheal and intestinal colonization by opportunistic pathogens in intensive care patients.

ObjectiveInfections caused by multidrug-resistant Gram-negative bacilli (MDR-GNB) are a major issue in intensive care. The intestinal and oropharyngeal microbiota being the reservoir of MDR-GNB. Our main objective was to assess the link between the composition of the intestinal microbiota and the tracheal and intestinal colonization by MDR-GNB, and also by Enterococcus spp. and yeasts.MethodsWe performed a 2-month prospective, monocentric cohort study in the medical intensive care unit of our hospital. Patients ventilated >3 days and spontaneously passing feces were included. A fecal sample and an endotracheal aspiration (EA) were collected twice a week. MDR-GNB but also Enterococcus faecium and yeasts (as potential dysbiosis surrogate markers) were detected by culture methods. The composition of the intestinal microbiota was assessed by 16S profiling.ResultsWe collected 62 couples of feces and EA from 31 patients, including 18 feces and 9 EA positive for MDR-GNB. Forty-eight fecal samples were considered for 16S profiling. We did not observe a link between the diversity and the richness of the intestinal microbiota and the MDR-GNB intestinal relative abundance (RA). Conversely, we observed a negative link between the intestinal diversity and richness and the RA of Enterococcus spp. (pConclusionThe fecal MDR-GNB RA was not associated to the diversity nor the richness of the intestinal microbiota, but that of Enterococcus spp. was