D. Yong Research School of Astronomy and Astrophysics, Mt. Stromlo Observatory, Cotter Rd., Weston, ACT Australia A recent survey of a large sample of massive Galactic asymptotic giant branch (AGB) stars shows that significant overabundances of rubidium (up to 100 times solar) are present in these stars. Zirconium, on the other hand, is not enriched compared to the solar abundance. These observ...

A method is described for the isolation and purification of the sexual inducer produced by male colonies of the colonial green alga Volvox carteri. The procedure yields a highly purified preparation of the inducer. The biologically active principal is demonstrated to be a glycoprotein with a molecular weight of 32,000.

The study of the dependence of reactions on the concentration of various compounds is often of great value in determining reaction mechanisms . In chemical kinetics, it is often found that, according to van't Hoff's rule, the order of dependence of a reaction on the concentration of some compound involved in that reaction is equal to the number of molecules of the compound involved in each reac...

The three-dimensional image-reconstruction problem solved here for optical-sectioning microscopy is to estimate the fluorescence intensity lambda(x), where x epsilon R3, given a series of Poisson counting process measurements [Mj(dx)]jJ = 1, each with intensity [formula: see text] with [formula: see text] being the point spread of the optics focused to the jth plane and sj(y) the detection prob...

The nature of the variation which is created by mutation can show how the direction of evolution is constrained by internal biases arising from development and pre-existing design. We have attempted to quantify these biases by measuring eight life history characters in developmental mutants of Volvox carteri. Most of the mutants in our sample were inferior to the wild type, but deviated by less...