Natural acceleration of charged particles occurs within a variety of physical contexts and through a range of physical processes.``Cosmic'' charged particle acceleration can involve particle energies and energy changes from less than one electron Volt (eV), and on through kilovolt (keV) energies, up to 1018 and perhaps 1020 eV. These acceleration

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Chopping between the source and 1 or 2 background positions was an ISOPHOT observing mode for faint source photometry. More than 7000 observations of this type were performed during the mission. We review the main instrumental effects related to chopping, and describe the data reduction steps and calibration strategies developed for this mode. A

It is known that the convective motions at solar photosphere level are visible in the frequency domain through the so called ""solar noise"". Time-resolved differential CCD photometry time series form 2 to 4 days long obtained at the Observatorio del Teide Izaña (Tenerife) using the 1m telescope of the Optical Ground Station (OGS) have been taken

The OSIRIS Tunable Emission Line Object survey (OTELO) will provide a deep, complete sample of active galactic nuclei (AGN), and able to separate them accurately from nuclear star forming galaxies based on line strength ratios. The OTELO survey will be able to address several still open questions about the nature of AGN and their host galaxies.

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