Both linear and nonlinear analysis are used to gain a better understanding of the effects of multi-dimensional transfer of energy by radiation in spatially structured stellar atmospheres. Information on the radiative response of RE (radiative equilibrium) model atmospheres to temperature fluctuations is obtained. Whether or not such perturbed

The authors have measured the Li abundance in a sample of 37 field dwarfs of low metallicity. Stars with [Fe/H] -1.4 ("EMD" stars) form a much more homogenous population w.r.t. 7Li than do the stars with somewhat higher metallicities. The authors argue that the warmer EMD stars (6000K Teff 6300K) show little Li depletion, and that their

The authors present a spectroscopic analysis for the gravity determination of τ Ceti on the basis of a new and high quality set of data. The iron lines are studied by using the Oxford oscillator strengths. The results are compared with those obtained with "solar" oscillator strengths. Non-LTE effects seem to be important in this star. The Fe I at

The authors developed routines for intensity, equivalent width, and radial velocity measurements on CES plus Reticon spectra obtained with the ESO 1.4 m telescope. In order to achieve the optimal recovery of the signal, the noise has to be minimized by removing any parasitical effect. Special care has been devoted to the correction for remanence

The authors study the behaviour of a family of algorithms with different weight functions in an approach to algorithms working in real time. The behaviour of these algorithms is sorted by the sensitivity to noise photons. A "modified" gaussian function (a gaussian centered at the origin but whose peak is set to zero) presents good behaviour like

Near-infrared JHKL photometry of more than 200 stars in the open clusters Tr 14, Tr 15, Tr 16, Cr 228, and Cr 232 in the Carina Nebula is presented. By comparing these results with the available visual photometry and spectroscopy, it is found that the intracluster reddening is characterized, except in Tr 15, by a 'normal' extinction law for lambda