Complex sentence: In 2006, the Project added a branch at The University of Arizona in Tucson, Arizona, but in December 2010, the Tucson-office was closed in preparation for two new satellite research offices.
Split into simpler sentences: In 2006, the Project added a branch at The University of Arizona in Tucson, Arizona. In December 2010, the Tucson office was closed in preparation for two new satellite research offices.