Dynamical problems associated with the orbital motion of dust particles in strong gravitational and radiation fields are analyzed. The general relativistic equations for the motion of a single dust particle are derived, and the static, spherically symmetric situation described by the Schwarzschild metric is considered. Two sharply differentiated

SE PRESENTAN OBSERVACIONES CARTOGRAFICAS Y FOTOMETRIA INTEGRAL EN EL INFRARROJO EN LAS BANDAS J H Y K DE 13 CUMULOS GLOBULARES QUE SE EXPLICAN EN BASE A UN MODELO SINTETICO DE COLORES INTEGRALES CONSTRUIDO CON RESULTADOS EMPIRICOS DE COLORES ESTELARES PARA LA POBLACION II. SE PRESENTAN OBSERVACIONES FOTOMETRICAS DE ESTRELLAS AISLADAS EN LOS CUMULOS

MODELOS DE ACELERACION DE PARTICULAS EN ONDAS DE CHOQUE POR EL MECANISMO DE FERMI DE PRIMER ORDEN SE APLICAN A JETS EN NUCLEOS GALACTICOS ACTIVOS Y CUASARES. SE SIMULAN LAS PROPIEDADES OBSERVACIONALES DE LA EMISION NO TERMICA DE LOS ELECTRONES ACELERADOS EN ONDAS DE CHOQUE EXTRAGALACTICAS RESOLVIENDO LA ECUACION DE TRANSPORTE DE RADIACION

Although the QSO PKS 2128 - 123 appears as highly variable in the I band, with Delta-I of up to 1.69 mag, it is a moderate amplitude variable object in the other bands of the present UBVRI observations. Excluding these I fluxes, the average continuum is well fitted by a power law when the Balmer continuum contribution, which enters the V band, has

This publication is a collection of pictorial comparisons of prominent physiographic features found on Mars and Earth, consisting of equal-scale side-by-side pairs or cartographic overlays. Martian features compared with terrestrial ones include Valles Marineris, the Tharsis bulge, Olympus Mons, the Hellas and Argyre basins, areas of catastrophic

Contents: The classical scheme for gas phase reactions. Charge transfer at low energies. Electron abundances in dense clouds. Some problems in interstellar S chemistry. Gas versus grain: the case of HCN and HNC. Remarks.