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

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Agronomic, economic and ecological aspects of the papaya (Carica papaya) production in Tabasco, Mexico

The cultivation of papaya is important in the tropic because it provides source of income to the farmer within a short time. Statistical data were obtained from farmers located in the Chontalpa, Rios and Centro-Sierra regions; the size of the survey was 67 farmers. The study shows the results of the farmers’ problem in a drastic reduction of their productivity because of the virosis and low prices in commercialization. The farmers were classified into three levels of technology, “low”, “middle” and “high”. The first one covers 88% of the farmers in seasonal conditions in contrast with the high technology that concentrates 4.5% in irrigation conditions. According to the technology used, the fertilizer shows more yields. Economically, the high technology had an internal tax return of 0.43 in comparison with the low technology of 0.25, which means that the investment is recovered with different yields. However, the use of high technology makes the system more competitive. Key words

Changes in the trajectory of the radio jet in 0735+178?

We present multi-epoch 8.4 and 43 GHz Very Long Baseline Array images of the BL Lac object 0735+178. The images confirm the presence of a twisted jet with two sharp apparent bends of 90$^{\circ}$ within two milliarcseconds of the core, resembling a helix in projection. The observed twisted geometry could be the result of precession of the jet inlet, but is more likely produced by pressure gradients in the external medium through which the jet propagates. Quasi-stationary components are observed at the locations of the 90$^{\circ}$ bends, possibly produced by differential Doppler boosting. Identification of components across epochs, since the earliest VLBI observations of this source in 1979.2, proves difficult due to the sometimes large time gaps between observations. One possible identification suggests the existence of superluminal components following non--ballistic trajectories with velocities up to $11.6\pm 0.6 h_{65}^{-1} c$. However, in images obtained after mid-1995, components show a remarkable tendency to cluster near several jet positions, suggesting a different scenario in which components have remained nearly stationary in time at least since mid-1995. Comparison with the earlier published data, covering more than 19 years of observations, suggests a striking qualitative change in the jet trajectory sometime between mid-1992 and mid-1995, with the twisted jet structure with stationary components becoming apparent only at the later epochs. This would require a re-evaluation of the physical parameters estimated for 0735+178, such as the observing viewing angle, the plasma bulk Lorentz factor, and those deduced from these.Comment: 18 pages, 5 figures, accepted for publication in MNRA

The formation of planetary disks and winds: an ultraviolet view

Planetary systems are angular momentum reservoirs generated during star formation. This accretion process produces very powerful engines able to drive the optical jets and the molecular outflows. A fraction of the engine energy is released into heating thus the temperature of the engine ranges from the 3000K of the inner disk material to the 10MK in the areas where magnetic reconnection occurs. There are important unsolved problems concerning the nature of the engine, its evolution and the impact of the engine in the chemical evolution of the inner disk. Of special relevance is the understanding of the shear layer between the stellar photosphere and the disk; this layer controls a significant fraction of the magnetic field building up and the subsequent dissipative processes ougth to be studied in the UV. This contribution focus on describing the connections between 1 Myr old suns and the Sun and the requirements for new UV instrumentation to address their evolution during this period. Two types of observations are shown to be needed: monitoring programmes and high resolution imaging down to, at least, milliarsecond scales.Comment: Accepted for publication in Astrophysics and Space Science 9 figure

Utilidad de la exploración física para el diagnóstico de neumonía infantil adquirida en la comunidad en un centro de atención primaria

ObjetivoDeterminar la utilidad diagnóstica de tres signos clínicos (fiebre, tos, estertores crepitantes) para el diagnóstico de neumonía en niños; evaluar la concordancia en la interpretación de la radiografía de tórax por dos radiólogosDiseñoEstudio de pruebas diagnósticasEmplazamientoAtención primariaMaterialTrescientas cincuenta historias clínicas de niños a los que se practicó una radiografía de tórax urgente para diagnosticar neumonía entre el 1 de enero de 1996 y el 30 de junio de 1999Mediciones principalesa) Prevalencia de neumonía en toda la muestra y en dos subgrupos de edad: igual o inferior a 5 años y superior a 5 años; b) cocientes de probabilidad positivo y negativo e intervalos de confianza del 95% (IC del 95%). Se consideró la radiografía de tórax como estándar de referencia, y c) concordancia interradiólogos-índice kappa (?)ResultadosLa prevalencia de neumonía en toda la muestra fue del 22,9% (IC del 95%, 18,5-27,3); en los niños de 5 años de edad o menores fue del 20,4% (IC del 95%, 15,6- 25,2), y en los mayores de 5 años, del 31,3% (IC del 95%, 21,1-41,4). Los signos estudiados sólo tuvieron alguna utilidad para confirmar el diagnóstico en mayores de 5 años: el cociente de probabilidad positivo fue de 3,52 (IC del 95%, 1,28-9,69) y los radiólogos coincidieron en el diagnóstico en el 93,1% de las radiografías de tórax (k=0,8; IC del 95%, 0,77-0,83)ConclusionesEn este estudio no se constató la presencia de un subconjunto de signos clínicos que aseguren de forma inequívoca el diagnóstico de neumonía en niñosObjectiveTo determine the diagnostic usefulness of three clinical signs (temperature, cough, crepitant stertor) for diagnosing pneumonia in children.To evaluate the agreement of two radiologists in evaluating thoracic x-rays (TXR)DesignStudy of diagnostic testsSettingPrimary careParticipants350 clinical histories of children who had an urgent TXR to diagnosis pneumonia between 1st January 1996 and 30th June 1999Main measurementsa) Prevalence of pneumonia in the entire sample and two age-based sub-groups: aged 5 years and under, and over 5; b) positive probability quotients (PQ+) and negative ones (PQ-) and 95% confidence intervals (95% CI). The TXR was seen as the reference standard, and c) kappa index (?) for inter-radiologist concordanceResultsPrevalence: the entire sample, 22.9% (95% CI, 18.5-27.3); children aged 5 or less, 20.4% (95% CI, 15.6-25.2); aged over 5, 31.3% (95% CI, 21.1-41.4). The signs studied were only of any use in confirming the diagnosis in children over 5: PQ+ was 3.52 (1.28-9.69). Radiologists coincided in their diagnosis in 93.1% of the TXR (k=0.8; 95% CI, 0.77-0.83)ConclusionsThis study did not prove that there was a sub-grouping of clinical signs which confirmed unmistakeably the diagnosis of pneumonia in childre

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