Atomic Energy Commission Report AECD-3217

Abstract: "The leakage of neutrons from a heterogenous pile with finite aides is calculated developing the method used in CP-992. The change in the fraction of neutrons absorbed by the moderator is obtained using the results of the calculation of the leakage.

Atomic Energy Commission Report AECD-3214

Abstract: "An accurate calculation is given for the quantity which corresponds to the diffusion length in the theory of the pile. The procedure is to establish a relationship between the diffusion length and the change in thermal utilization from a pile with infinite sides to one with sides of a finite length. The calculation of this change in the thermal utilization is then carried through. Approximation to the answer and numerically exact calculations are given in the report. The results show that for radif very near the optimum values the exact diffusion length is slightly larger than the one obtained from the usual formula...However, over most of the range of radii the exact diffusion length is smaller than the approximate one.

Rapid and reversible epigenome editing by endogenous chromatin regulators

Understanding the link between epigenetic marks and gene regulation requires the development of new tools to directly manipulate chromatin. Here the authors demonstrate a Cas9-based system to recruit chromatin remodelers to loci of interest, allowing rapid, reversible manipulation of epigenetic states