The main part of this thesis is devoted to the derivation and study of formulas for the probability of survival of the haploid and diploid yeast cell, based on models proposed by Zirkle and Tobias. Some properties of so-called completely monotonic functions are developed, and the results are applied to the investigation of some of the more complicated formulas. Finally the theoretical expressions are compared with the experimental data obtained by Tobias.

The energy distributions of neutrons in the 3-10 Mev energy range resulting from the bombardment of thin U targets are being investigated by the measurement of proton recoils in photographic plates.

In the past it was felt that the easiest way to treat a three group equation for a MTA lattice was to solve it without certain terms. This iterative procedure converged rapidly for a medium with depleted uranium fuel, and in fact, a second iteration was not needed.