A measure of complexity based on a probabilistic description of physical systems is proposed. This measure incorporates the main features of the intuitive notion of such a magnitude. It can be applied to many physical situations and to different descriptions of a given system. Moreover, the calculation of its value does not require a considerable

This volume deals with the most recent theories of violent star formation. It covers the formation and evolution of new stellar clusters, and explores all the possible consequences in a wide variety of objects where massive stellar bursts have occurred. It thus presents an alternative model to that which suggests supermassive black holes are the

In the starburst model for active galactic nuclei (AGN), the observed broad emission lines and their variability are generated by compact, strongly radiative supernova remnants. These compact remnants are expected to occur preferentially in the central region of massive early-type galaxies undergoing a nuclear burst of star formation. This paper

As targets of the fourth photometry campaign of the STEPHI network, the Delta Scuti stars BNCnc (HD73576) and BUCnc (HD73763) were simultaneously monitored during a three-week, three-continental run, in February 1992 (Belmonte et al 1994). Both stars are members of the Praesepe cluster. The ''constant'' star HD73712 (KW284) was chosen as comparison

A 16-min time series of two-dimensional "Multichanel Subtractive Double Pass" spectrograms, recorded in the NaD_2_ 5690 line, has been used to study the vertical structure of the photosphere and, in particular, the penetration of granules. A statistical and a morphological investigations have been made. The 5-min oscillations have been carefully

This paper summarizes the common properties of the currently known galactic black hole candidates. Particular emphasis is given to optical studies of the best candidates (those soft X-ray transients with dynamical evidence) and the problem of the mass determination. The technique used to achieve this goal (which has been applied to A0620-00, GS2023