Article history: Received 1 September 2007 Available online 22 July 2008

One of the basic results in graph colouring is Brooks' theorem [R.

It is widely accepted that predation plays a critical role in determining zooplankton community structure in ponds and lakes. The relationship between fish planktivory and zooplankton species composition has been discussed since the early work of HRBACEK et al. (1961) and BROOKS & DODSON (1965). Size-selective predation by fish may produce changes in zooplankton community structure. Phenomena f...

underlying developmental research are often only implicit, yet they guide data collection and interpretation of results. For example, a number of researchers have provided data concerning intercorrelations among behaviors presumed to be indices of attachment (e.g., Coates, Anderson & Hartup 1972; Maccoby & Feldman 1972). Noting that such "index" behaviors do not intercorrelate highly, do not sh...

Donald Kennedy and Brooks Hanson ("A time of opportunity," Editorial, 30 Jan., p. 589) clearly are aware of the extraordinary foundation of scientific knowledge about the origin and history of the Moon, Earth, planets, and solar system that came as a consequence of U.S. explorations of the moon. I was surprised, however, by their implication that the time of human exploration of space has passe...