The presence of coconut in southern Panama in pre-Columbian times: Clearing up the confusion

Background The pre-Columbian presence of coconut on the Pacific coast of Panama is attested by a number of independent written accounts. However, recent papers question their accuracy and conclude that coconut was introduced to the region by the Spaniards after their conquests. Scope In order to examine the value of such claims, an extensive search was conducted of the relevant historical accounts of coconut in America and in the Orient. Key Results The Spanish chronicler Oviedo (1478-1557) is found to have effectively used fruit and seed size to distinguish coconut from other palms. In addition, it is shown that he has been inaccurately faulted with incorrectly representing a cluster of coconuts. The original drawing, a cluster of a native Bactris, was in the marginalia and was only assigned to coconut after Oviedo's death. Finally, the location is identified of a coastal Panamanian site described by Pedro Mártir de Anglería and where tidal dispersal of coconuts was observed. Conclusions This previously overlooked evidence confirms the pre-historical presence of coconut in Panama. Genetic data indicate that it must have been brought there directly or indirectly from the Philippines. But when, where and by whom remains a subject of research. Further molecular marker studies, computer simulation of natural drift and archaeological research could contribute to this research. (Résumé d'auteur

The Bright Side of Coulomb Blockade

We explore the photonic (bright) side of dynamical Coulomb blockade (DCB) by measuring the radiation emitted by a dc voltage-biased Josephson junction embedded in a microwave resonator. In this regime Cooper pair tunneling is inelastic and associated to the transfer of an energy 2eV into the resonator modes. We have measured simultaneously the Cooper pair current and the photon emission rate at the resonance frequency of the resonator. Our results show two regimes, in which each tunneling Cooper pair emits either one or two photons into the resonator. The spectral properties of the emitted radiation are accounted for by an extension to DCB theory.Comment: 4 pages, 4 figures + 3 pages, 1 figure supplementary materia

Evaluation du cout economique de l’eau d’irrigation dans la zone office du Niger au Mali

L’objet de cet article est d’évaluer le coût économique de l’eau d’irrigation dans la zone Office du Niger (ON) au Mali. Pour l’atteinte des objectifs, deux types de coût ont été estimés (coût financier et coût économique de l’eau d’irrigation. Les données de l’enquête ont été combinées avec la revue de la littérature de l’ON et surtout avec des articles pertinents relatifs au coût économique de l’eau  d’irrigation dans des périmètres irrigués analogues dans d’autres pays africains afin d’alimenter utilement notre analyse critique etdiscussion. Les résultats ont montré que le coût financier est 63 474 FCFA, soit 97 €1 en moyenne et le coût économique est 185 446 FCFA/ha, soit 283 €/ha en moyenne. L’évaluation du coût de l’efficience donne 6 FCFA/m3 soit 0,009 €/m3 qui est supposé très faible. La redevance de l’eau contribue en moyenne 10% à l’entretien de l’ensemble des réseaux hydrauliques. En conclusion, la redevance payée par les producteurs est un coût social qui ne prend pas en compte le coût des aménagements hydro agricoles. Sans l’intervention de l’Etat, la production rizicole dans ce système allait connaitre d’énormes problèmes de rentabilité. Mots-clés : Evaluation-Coût économique-Eau d’irrigation - Office du Niger -Mali.   English title: Evaluation of the economic cost of irrigation water in the office du Niger in Mali The purpose of this article is to assess the economic cost of irrigation water in the Office du Niger area in Mali.To achieve the objectives, two types of cost were estimated (financial cost and economic cost of irrigation water. The data were combined with the review of the Office du Niger literature and especially with relevant articles relating to the economic cost of irrigation water in similar irrigated areas in other African countries to usefully contribute our critical analysis and discussion.The results showed that the average financial cost is about 63,474 FCFA/ha or 97 €/ha and the average economic cost is about 185,446 FCFA/ha or 283 €/ha. The cost of efficiency assessment gives 6 FCFA / m3 or 0.009 € / m3 which is assumed to be very low. Water charges contribute on average of 10% to the maintenance of all hydraulic networks. And the operators’ contribution represents only 4%.In conclusion, the royalty paid by the producers is a social cost which does not take into account the cost of hydro agricultural development. Without state intervention, rice production in this system would experience enormous problems and tertiary hydraulic networks. Keywords : Evaluation-Economic cost- Irrigation water- Office of Niger- Mali