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SCIENTIFIC ABSTRACT We propose to use ISOPHOT at 24, 64, and 100 um and ISOCAM at 15 um to study galaxies at z > 0.1 which, based on their blue colors, are thought to be undergoing bursts of star formation. Most of these galaxies were discovered as radio sources in the deep 1.4 GHz surveys. Many have complex optical morphologies suggesting that they are interacting and merging systems, although other explanations such as jet-induced star formation have been put forward. These galaxies are thought to account for the excess, or "upturn," in the 1.4 GHz radio source counts detected at flux densities below a few milliJanskys. Our study will show if there exist significant obscured populations of young stars in these galaxies, and it will substantially extend our knowledge of the population of IR-luminous galaxies to the realm at z > 0.1 and possibly out to z = 1-2. The total luminosities and dust color temperatures will be determined from the fluxes at 64 and 100 um, where the spectral energy distributions peak. The 15, 24, and 64 um fluxes may indicate the presence of active nuclei which produce a peak in this spectral region in several local Seyfert archetypes. OBSERVATION SUMMARY We propose to observe 51 galaxies for an Autumn launch (exclusion hole in Orion) or 58 galaxies for a Spring launch (exclusion hole in the Galactic Center), most at 24, 64, and 100 um with PHOT and at 15 um with CAM, for a total spacecraft time of 17 hours. Five hours of this spacecraft time have been contributed by Mission Scientist Alan Moorwood. Most of the sources have 1.4 GHz flux densities of a few mJy, with expected 60 um flux densities of greater than 100 mJy if the radio-infrared relation for local galaxies applies to these distant ones. Each of these brighter galaxies will be observed using PHT filters C100, C60, and P25 and CAM filter LW3. A smaller sample of fainter galaxies, with expected 60 um flux densities greater than 30 mJy will be observed only with C100, C60, and LW3. The PHOT observations will employ triangular chopping, and the CAM imaging will use 2x2 microscans. Because these galaxies are grouped in several small regions of the sky, we propose to use concatenation to substantially reduce overhead. In addition to the purely scientific reasons mentioned in the abstract, the CAM images will verify telescope pointing and aid in the assessment of cirrus contamination at the longer wavelengths.