1. Senior Scientist, Dept. of Economic and Technological Change, Center for Development Research, Univ. of Bonn, Walter-Flex-Str. 3, 53113 Bonn, Germany.
2. Senior Scientist, UN-Water Decade Programme on Capacity Development (UNW-DPC), United Nations Univ., Hermann-Ehlers-Str. 10, 53113 Bonn, Germany; formerly, Dept. of Ecology and Natural Resources Management, Center for Development Research, Univ. of Bonn, Walter-Flex-Str. 3, 53113 Bonn, Germany (corresponding author).