730 research outputs found
Biocontrol of cassava pathogens: A useful approach
Research results obtained during 1975-87 on the biocontrol of cassava pathogens are summarized with emphasis on the use of fluorescent pseudomonads as biocontrol agents in different cassava production systems. Evidence of biocontrol of Uromyces spp. by the mycoparasite Darluca filum is reviewed. Findings on biocontrol with the beneficial bacteria Pseudomonas putida and P. fluorescens are examined regarding their isolation, survival, effect on cassava seedlings under greenhouse conditions, and practical applications (bicontrol of Xanthomonas campestris pv. manihotis, Pythium spp., and Diplodia manihotis). Different effects observed with treatments with beneficial bacteria on cassava plant growth are summarized: increased root wt. length, and no., and faster root initiation. These results indicate that the biocontrol of cassava pathogens is feasible. (CIAT
Cassava bacterial blight (CBB)
The most important bacterial disease of cassava is cassava bacterial blight (CBB). This disease was first recorded in Brazil but was later reported in Colombia and observed in several other countries in South America and Africa. Symptoms of this disease are leaf spotting, wilting, dieback and gum exudation on young shoots. Vascular strands of infected petioles and stem necrose appear as brown strings. The bacterium is spread by the use of infected planting material and infected tools. The disease spreads rapidly during the rainy season because of rain splash. The disease can be eradicated by removing and burning all plant debris, using healthy planting material, preventing the movement of people, tools and planting material from infected to clean areas, and using resistant cultivars. (CIAT
How to Find Suitable Ontologies Using an Ontology-based WWW Broker
Knowledge reuse by means of outologies now faces three important problems: (1) there are no standardized identifying features that characterize ontologies from the user point of view; (2) there are no web sites using the same logical organization, presenting relevant information about ontologies; and (3) the search for appropriate ontologies is hard, time-consuming and usually fruitless. To solve the above problems, we present: (1) a living set of features that allow us to characterize ontologies from the user point of view and have the same logical organization; (2) a living domain ontology about ontologies (called ReferenceOntology) that gathers, describes and has links to existing ontologies; and (3) (ONTO)2Agent, the ontology-based www broker about ontologies that uses the Reference Ontology as a source of its knowledge and retrieves descriptions of ontologies that satisfy a given set of constraints. (ONTO)~Agent is available at http://delicias.dia.fi.upm.es/REFERENCE ONTOLOGY
Rutinas, valores y condicionantes en la producción de la noticia: el testimonio de cuatro directores de medios informativos en Monterrey, México.
En respuesta a la necesidad
de contar con mayor información y
comprensión de los condicionantes
que se presentan en la producción de
las noticias en Iberoamérica, este trabajo,
presenta los testimonios de
cuatro comunicadores de Monterrey,
México, que ocuparon puestos directivos
en medios informativos impresos
y electrónicos en la década de los
ochenta. A través de entrevistas en
profundidad, el estudio ofrece evidencias
sobre los complejos procesos
de negociación y grados de autonomía
de directivos y conductores de
televisión frente a los intereses económicos
e ideológicos de los dueños
de los medios y de la élite local en el
poder. Asimismo, permite identificar
las principales rutinas de trabajo e influencias
individuales que moldean e
inciden en los contenidos noticiosos
locales
Reference Ontology and (ONTO)2 Agent: The Ontology Yellow pages
Knowledge reuse by means of ontologies faces three important problems at present: (1) there are no standardized identifying features that characterize ontologies from the user point of view; (2) there are no web sites using the same logical organization, presenting relevant information about ontologies; and (3) the search for appropriate ontologies is hard, time-consuming and usually fruitless. To solve the above problems, we present: (1) a living set of features that allow us to characterize ontologies from the user point of view and have the same logical organization; (2) a living domain ontology about ontologies (called Reference Ontology) that gathers, describes and has links to existing ontologies; and (3) (ONTO)2Agent, the ontology-based WWW broker about ontologies that uses Reference Ontology as a source of its knowledge and retrieves descriptions of ontologies that satisfy a given set of constraints
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