Attention is given to problems which arise when an attempt is made to use observational material to clarify the mechanisms responsible for the heating of the chromosphere in a late-type star, in order to derive a clearer physical view of the nature of a chromosphere, its relation to the underlying photosphere, and the overlying corona. Problems

We spatially resolved the symbiotic star CI Cam, about 6 months after its April 1998 outburst, using the IOTA stellar interferometer. We measured the diameter of the dust shell in the H and K infrared bands over a range of position angles. We will discuss the relationship between these results and other ongoing observations of CI Cam.

We present optical broad- and narrow-band imaging of a sample of a dozen barred galaxies. These images are analysed in conjunction with our previously published near-infrared imaging of their central regions and with literature values for, e.g. bar strengths and the total star formation activity of the galaxies. We present B, I and Hα images, and

We present high-resolution Hα velocity fields and rotation curves of the circumnuclear star-forming regions of five barred galaxies. Two of the five objects show substantially smaller initial rises than the three others; these two objects also have spiral structure inside the circumnuclear star-forming ring.

Galactic globular clusters (GCs) are known to host multiple stellar populations: a first generation (FG) with a chemical pattern typical of halo field stars and a second generation (SG) enriched in Na and Al and depleted in O and Mg. Both stellar generations are found at different evolutionary stages (e.g., the main-sequence turnoff, the subgiant

We present a procedure for obtaining the mean density of clusters and their associated structures in a very general type of distribution. We first consider the one-dimensional case, and then use it to develop the procedure according to the d-dimensional case. These procedures require the probability that a randomly placed body should contain no