PN, Biology aml Medicine Monthly Status Report, variables behave more or less similarly showing a decrease with increasing X-ray dosage. These variables are total eges laid, total days on which eggs were produced, three-day hizhest egg yield, percent of life female produced eggs, three-day highest hatchability, percent af eggs fertilized, and parcent of lifes when males were fertile. Two variables, days of life for males and for females failed to show a significant trend with increasing dosage « A pilot experiment with mice is now in progress and the Drosophila experiments are being continued. Plans for this project have been expanded to include study of the effects of chronic gamas exposure upon physiological processes and longevity of mica. Genstics In a mamuscript to te submitted for publication in the American Naturalist, Dr. Bruce Wallace summarizes the first two years! results In the study of drosophila populationa exposed to acute and chronic ionising radiation. The rates of accumlation of lethal, semi-lethal and sub-vital mtations are presented, A consideration of the frequencies of lethals, semi-lethals and sub-vitals within the populations and of estimatea of the adaptive values of the populations suggests that hetterotic cene combinations have been developed within some of these populations. These results have an important bearing on the estination of damage to populations resulting in rene mitationg. Civil Defense Personnel Shelters for AEC Installations _ Discussions were held with a representative of Armeo Drainage ani Metal Products, Inc. om underground shelter possibilities. Plans and costs for an acceptable structure have been secured from the company. FCDA Test Exercise Members of the Branch have participated in conferences with repre- gentetives of the FCDA and other interested ageneles on the proposed FCDA test to determine the effects of an atomic bomb on structures amd shelters. Desieon Criteria for New AEC Construction Work 1s continuing, in cooperation with the reaponsible progran divisions, on design standards for protective construction in connection with new plants and facilities. menstareeees | GPO OFFICER) i 16—55741-1 cece coceeeneees eneeeeeeeeneneeeens