550 research outputs found

    The Taylor principle and global determinacy in a non Ricardian world

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    The Taylor principle is quite usually considered as a central condition for price determinacy. Recently, however, this has been questioned on several grounds, notably because (i) this condition is a condition for local determinacy, not global determinacy (ii) it has been derived in "Ricardian" economies, and it appears that going to a non-Ricardian framework makes a very big difference for the determinacy conditions. In this paper we scrutinize the two issues together, and we find that for non-Ricardian equilibria the Taylor principle is replaced by another "financial dominance" criterion.Taylor principle ; Taylor rules ; global determinacy ; price determinacy ; non Ricardian economies ; non Ricardian equilibria

    Microfibrous TiO2 supported photocatalysts prepared by metal-organic chemical vapor infiltration for indoor air and waste water purification

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    The photocatalytic degradation of gaseous (toluene) and aqueous (imazapyr, malic acid, orange G) pollutants over TiO2 supported photocatalysts is investigated using a batch reactor. A strong influence of the microstructural characteristics of TiO2 on the decomposition kinetics of the pollutants is found. Well crystallized, porous TiO2-anatase films grown under low pressure at 400–500 8C by MOCVD on glass plates and by MOCVI on glass micro-fibers are the best heterogeneous photocatalysts, showing the highest activity. We demonstrate a good control of these characteristics by choosing the deposition parameters. Achieving conformal coverage (i.e. good infiltration) of glass micro-fibers by the TiO2 thin films has also a strong influence on the photocatalytic activity. A correlation between optimal infiltration, film microstructure and photocatalytic activity is established. Strong similarities between optimal photocatalytic decomposition rate in gas and liquid phase were found with respect to the film microstructure and the photocatalyst mass. The total mineralization of the toluene was prevented because of the deactivation of the photocatalyst surface. However the reactivation of the photocatalyst was achieved by UV irradiation under oxygen stream. This allows a long-term use of the photocatalyst

    Satellite solar meteorology: operational use of the Meteosat system to compute solar irradiance

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    Solar radiation is a parameter of large importance in a wide range of human activities. This communication discusses the potentials of the new satellite Meteosat for operational mapping of solar irradiance at ground level

    Applying the European hydroacoustic standard on fish abundance estimation (EN 15910)

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    Hydroacoustics is an internationally approved method to study fish for abundance estimates and behaviour to increase our understanding of aquatic ecosystems. In Europe and North- America, the need to compare results between years, lakes and countries has been recognized and as a consequence of this, acoustic methods are being standardized. To study how the European standard Water quality – Guidance on the estimation of fish abundance with mobile hydroacoustic methods (CEN 2014) was perceived by different users, a joint evaluation of the implementation of the standard was performed in 2014 by hydroacoustic experts from three European countries. In some parts of the standard the participants´ actions were different from what was described by the standard, and in some cases methods differed among the participants. A general explanation for most of these cases was that stable equipment performance and experience from discrete surveys reduce the need of controlling actions. We suggest that the results of this study should be considered at the revision of the standard (EN 15910) scheduled for 2017

    Spatio-temporal variability of fish assemblages in the Gambia estuary (West Africa) observed by two vertical hydroacoustic methods : moored and mobile sampling

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    indexedccInternational audienceThe Gambia Estuary is one of the last estuaries in West Africa not to have been affected by strong environmental changes and adverse human disturbances. In order to describe the spatio-temporal change in fish biomass in this estuary, and the seasonal changes in fish size classes, five research surveys have been conducted at characteristic periods in the river's water regime and meteorological seasons. The fish assemblages were sampled by two vertical echosounding protocols: mobile surveys (zigzag transects) in the estuary and moored stations. The two sampling methods produced a similar image of the fish assemblages in terms of the distribution of total biomass and target strength distributions. Large fish aggregations were detected in the most marine area at the end of the wet season, and fish biomass increased through the dry season in the upstream zone. Fish were smaller at the beginning of the wet season and they were always larger in downstream areas

    A HLLC Riemann solver to compute shallow water equations with topography and friction

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    We consider the resolution, by a finite-volume method, of the two-dimensional model of the shallow water equations with topography and friction. Thanks to the property of invariance per rotation of the flux of shallow water equations, we show that the study of the 2D case rises from the good resolution of the monodimensional system of the shallow water equations. The numerical implementation is carried out by a finite volume scheme of Godunov type using an Riemann approximate solver of the type HLLC which preserves the positivity height of water and which is well adapted for the treatment of the shock waves. Lastly, numercal examples on academic problems are presented as well as a real case : application of the model to the phenomenon of flood of the town of Cotonou (BENIN) by the risings of the lagoon of Cotonou

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    Why inorganic salts decrease the TiO

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    Methodes numeriques pour la combustion supersonique : bilan et perspectives

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    Ce rapport correspond a une etude sollicite par le CNRS et presentee au colloque CNRS sur le PRC "combustion dans les superstatoreacteurs", Paris, 21-22 octobre 1991. On y examine les principales methodologies numeriques applicables en maillages structures ou non-structures, susceptibles d'etre incorporees a un code de calcul pour les statoreacteurs. La discussion porte sur trois themes majeurs : la generation et l'adaptation d'un maillage approprie a un calcul d'ecoulement interne - la construction d'un schema d'approximation pour un ecoulement de melange gazeux reactif - et l'efficacite de l'algorithme de resolution lorsque le modele de cinetique chimique peut etre raide
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