The global behaviour and fine structure of the distribution of sunspot decay rates from activity cycle 13 to 20 are presented. It is shown that the distribution of this parameter is lognormal. Statistically significantly lower values of decay rates are found in cycles 13, 14, and 18 for isolated spots. The complex groups had no appreciable changes.

The global behavior and fine structure of the distribution of sunspot decay rates from activity cycle 13 to 20 are presented. It is shown that the distribution of this parameter is lognormal. Statistically significantly lower values of decay rates are found in cycles 13, 14, and 18 for isolated spots. The complex groups had no appreciable changes.

An analysis is presented of high-resolution high SNR spectra of late-type chromospherically active dwarfs in Ca II H. Observational parameters employed are the total emission flux attributable to the chromosphere, the asymmetry of the emission component and its bisector, the ratio of the intensities of the blue and red H2 emission peaks, and the

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The revised physical assumptions incorporated into a previously published evolutionary model for stellar population synthesis in galaxies (Casuso et al., 1989) are outlined. Applying the present version of the model to well defined zones on the nucleus and along a spiral arm of NGC 2903, it is shown that the star-formation rate has increased during

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