1. Earth and Planets Laboratory, Carnegie Institution for Science, Washington, DC 20015
2. Earth Life Science Institute, Tokyo Institute of Technology, Tokyo 152-8550, Japan
3. Blue Marble Space Institute for Science, Seattle, WA 98104
4. Department of Mathematics and Statistics, Purdue University Northwest, Hammond, IN 46323
5. Sagan Fellow, NASA Hubble Fellowship Program, Space Telescope Science Institute, Baltimore, MD 21218
6. Department of Earth and Planetary Sciences, Johns Hopkins University, Baltimore, MD 21218