42 research outputs found

    Collecting wild Coffea species in Kenya and Tanzania

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    Plus de 30 populations d'espèces de Coffea comprenant C.arabica, C.eugenioides, C. tadenii et des espèces non identifiés parentes des groupes C.zanguebariae and C.mutindiensis ont été collectées au Kenya en 1977 et en Tanzanie en 1982. Le matériel collecté fût distribué a des collections en Champ au Kenya et en Tanzanie et en Côte d'Ivoire via des procédures de quarantaine

    Evaluation of the Magnetic Field Generated by the Inverter of an Electric Vehicle

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    In hybrid and electric vehicles, passengers sit very close to an electric system of significant power, which means that they may be subjected to high electromagnetic fields. The hazards of long-term exposure to these fields must be taken into account when designing electric vehicles and their components. Among all the electric devices present in the power train, the electronic converter is the most difficult to analyze, given that it works with different frequencies. In this paper, a methodology to evaluate the magnetic field created by a power electronics converter is proposed. After a brief overview of the recommendations of electromagnetic fields exposure, the magnetic field produced by an inverter is analyzed using finite element techniques. The results obtained are compared to laboratory measurements, taken from a real inverter, in order to validate the model. Finally, results are used to draw some conclusions regarding vehicle design criteria and magnetic shielding efficiency

    Recherche et caractérisation de sols résistants aux Pythium spp. en Amazonie brésilienne

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    Aux environs de la ville de Manaus (Amazonie brésilienne), les sols sont localisés dans deux écosystèmes: ‘terra firme’ recouverte de foret vierge ou cultivée et ‘varzea’, zones submergées chaque année et cultivées. 160 échantillons de sol ont été prélevés dans ccs deux zones, puis analysés afin de déterminer leur capacité de fonte des semis, causée par les Pythium spp.; 76 de ces sols semblaient non infestés, ou ne l'étaient que faiblement. Afin de déterminer leur réceptivité vis‐à‐vis des Pythium spp., les 76 sols ont été inoculés avec 10% d'un sol infesté naturellement, et la capacité d'infection a étéévaluée aprés des incubations de 4, 8, 12 et 16 semaines par tests biologiques sur jeunes plants de concombre. L'aptitude à supprimer les Pythium spp. n'est apparue que dans les écosystèmes ‘terra firme'et non dans les ‘varzeas’ submergés. La fréquence des sols pouvant supprimer la maladie semblait décroitre en fonction de la mise en culture: 82% dans les sols de foret vierge; 67% dans les sols de pépinières forestiéres; 53% dans les forets gérées; 31% dans les sols forestiers mis en culture avec des cultures variées; 7% dans les sols forestiers mis en culture et portant des cultures maraichères. On a constaté trois types d'aptitude à supprimer les Pythium spp. aprés inoculation des sols: (1) résistance apparaissant rapidement et se maintenant à un niveau élevé et constant (jusqu'à 16 semaines); (2) résistance initiate élevée, mais non durable; (3) résistance initialement faible, mais croissante avec le temps. Une partie de cette dynamique semble etre sous controle microbien. Le développement agricole autour de Manaus ainsi que les systèmes de culture intensifs peuvent rapidement modifier les écosystèmes microbiens des sols et nuire à leur capacité naturelle à supprimer les Pythium spp. Copyright © 1987, Wiley Blackwell. All rights reserve

    The main pathogens of cultivated plants on Careiro Island

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    Phytosanitary observations were carried out during two years on Careiro Island to identify the main crop diseases. A description of the symptoms and an evaluation of disease importance and those factors affecting its development were made for each pathogen

    Agricultural systems on Careiro Island

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    Land use systems of the Careiro Island are strictly governed by the annual flooding regime and seasonal rains. The topography gives rise to a mosaic of environments used by farmers according to land availability during the year. Five areas have been defined according to the physical and socio-economic characteristics of the main farming landscapes. The dwellings and agroforestry systems are always situated on the highest land, above the average flood levels. The different land use systems which have been analysed here are: the orchard, plant cultivation for food subsistence, commercial horticultural crops, cultivation of fibrous plants and pastures. At present socio-economic pressures are causing a new orientation towards monospecific fruit-tree plantations, commercial horticulture and pasture for cattle breeding

    Neo-Aramaic and Kurdish Folklore from Northern Iraq

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    This comparative anthology showcases the rich and mutually intertwined folklore of three ethno-religious communities from northern Iraq: Aramaic-speaking (‘Syriac’) Christians, Kurdish Muslims and—to a lesser extent—Aramaic-speaking Jews. The first volume contains several introductory chapters on language, folkore motifs and narrative style, followed by samples of glossed texts in each language variety. The second volume is the anthology proper, presenting folklore narratives in several distinct varieties of North-Eastern Neo-Aramaic and Northern and Central Kurdish. The stories are accompanied by English translations. The material includes different genres such as folktales, legends, fables and anecdotes, and is organised into seven thematic units. The folkloristic material of these three communities is shared to a large extent. The anthology is, therefore, a testament to the intimate and long-standing relations between these three ethno-religious communities—relations that existed in a multilingual environment centuries before the modern era of nationalism
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