UNCLASSIFIED virgin females. The pregnant females were sacrificed, and it was found. that the foetal death rate showed an increase in comparison with nonirradiated controls. The percentage of deaths for each group was: Control group.......... 6.46 per cent Gamma-ray exposure..... 19.37 per cent X YAYB.. cece sscacaessee 19.92 per cent After 60 days the same male animals were used in repeating the experiment. The values obtained after sacrifice of the second group of pregnant females were 7.39 percent for gamma exposure and 8.19 percent for X rays. This result does indicate a period of recovery and may be due to dominant lethal mutations induced during exposure in the more mature testis cells. Research in photosynthesis. At Oak Ridge National Laboratory, recent information has been reported in connection with the activity of light energy in photosynthesis. It has been known for some time that green plants fluoresce and that the fluorescence is the back reaction from excited chlorophyll which has absorbed light. When the lights are turned off, the fluorescence ceases in less than 107f seconds and is felt to represent the reversibility of the first step in light absorption by chlorophyll—namely, the formation of excited chlorophyll. Investigations have shown that there is also a much weaker light emission which lasts for Bome seconds after the plant is piaced in the dark. The emission spectrum of this delayed weak light has been shown to be the same as the fluorescence of chlorophyll. The data indicate that the delayed light emission represents the reversal of the first several steps in photosynthesis, the light ultimately coming only from the reversal of the first step. Radiation Instruments Special electronics development. The steering committee for the electronics development program held a meeting at Argonne National Laboratory on May 14, 15, 1953. In the light of technical developments and the increasing demand for special electronic requirements of various AEC installations, recommendations were made to accelerate studies in (a) basic research on the phenomena of photoelectric emission; (b) research development of new photoelectric and secondary emissive surfaces; (c) improvement of photomultiplier transit spread characteristics; (d) develop- ment of large photocathode multiplier tubes up to 30 inches and 36 inches in diameter; and (e) model shop fabrication of test quantities of tubes developed under the program. Research projects will-be undertaken with Notre Dame University, the Radio Corporation of America, and the Allen B. DuMont Laboratories. Review of standardization problems. The accelerated pace of in- strument development in the atomic energy field inevitably introduces a number of problems in standardization requirements. The Radiation Instru- ments Branch maintains close liaison with the many organizations of government and private industry and serves as representative or advisory member 26 UNCLASSIFTED- NOE ARCHIVES