Appendix E. Guest Colloquia Topic Group/Event Ecosystem dynamics, contaminant transport, and risk in semiarid systems David Breshears, Environmental Science Group, Los Alamos National Laboratory Beyond lung counting: application of liver and bone Milan Gadd, Senior Health Physicist, Rocky Flats Environmental Technology Site  Sources, emission, regional- and global-scale transport of Asian dust Xiaoye Zhang, Director, Dust & Geochemistry Laboratory, State Key Laboratory of Loess & Quaternary Geology, Chinese Academy of Sciences, China  New observations on the long-term behavior of cesium-137 and the actinides in surface soils Ward Whicker, Professor, Department of Radiological Health Sciences, Colorado State University  NIST low-level radiochemistry measurement quality assurance program Kenneth Inn, Group Leader, Office of Radiation Measurements, National Institute of Standards and Technology A hierarchical view of disturbance in the longleaf pine ecosystem William Michener, Associate Scientist, J.W. Jones Ecological Research CEMRC  Environmental effects of underground nuclear testing for peacetime applications Boris Golubov, Science Secretary, Scientific Council on Biosphere Problems, Russian Academy of Sciences, Moscow, Russia Natural and anthropogenic aerosols at Big Bend National Park, Texas Thomas Cahill, Professor Emeritus, Department of Atmospheric Sciences, University of California, Davis