Nuclear forensics using gamma-ray spectroscopy

Much of George Dracoulis's research career was devoted to utilizing gamma-ray spectroscopy in fundamental studies in nuclear physics. This same technology is useful in a wide range of applications in the area of nuclear forensics. Over the past several years, our research group has made use of both high- and low- resolution gamma ray spectrometers to: identify the first sample of plutonium large enough to be weighed; determine the yield of the Trinity nuclear explosion; measure fission fragment yields as a function of target nucleus and neutron energy; and observe fallout in the U. S. from the Fukushima nuclear reactor accident.Comment: 3 pages; 7 figures; conference proceedin

An Adverse Outcome Pathway for Potential Space Radiation Induced Neurological Diseases

Astronauts have begun to spend increasingly longer periods in space, putting themselves in foreign environments in order to explore the unknown. Space radiation is one of the largest health risks faced by astronauts on their missions. The space radiation environment has the ability to cause high levels of irreversible damage. Multiple sources of charged particle radiation exist in the space environment that may increase risk of carcinogenesis, degeneration of bodily tissue (e.g. gastrointestinal, cardiovascular, or pulmonary), acute radiation syndromes, and acute and late central nervous system (CNS) disorders. In order to help inform an understanding of the risk of degenerative CNS disease due to radiation exposure, an initial step is presented here to develop an adverse outcome pathway from radiation exposure focused on Alzheimers disease

Cooperon propagator description of high temperature superconductivity

A phenomenological description of the high-Tc superconductors based on the Cooperon propagator is presented. This model allows one to study the effects of local pairing correlations and long-range phase fluctuations on the same footing, both above and below Tc. Based on numerical calculations, it is shown that the two types of correlations contribute to the gap/pseudogap in the single-particle excitation spectra. The concourse of these two effects can induce low energy states, which should be observable in underdoped materials at very low temperature.Comment: LaTeX, 6 pages, 2 EPS figures; paper presented at New^3SC-3, Hawaii, 01/2001. To appear in Physica

THE EFFECT OF STOCHASTIC IRRIGATION DEMANDS AND SURFACE WATER SUPPLIES ON ON-FARM WATER MANAGEMENT

This study presents a procedure for simultaneously addressing stochastic input demands and resource supplies for irrigated agriculture within a linear modeling framework. Specifically, the effect of stochastic crop net irrigation requirements and streamflow supplies on irrigation water management is examined. Irrigators pay a self-protection cost, in terms of water management decisions, to increase the probability that stochastic crop water demand is satisfied and anticipated water supply is available. Self-protection cost is lower when increasing the probability that anticipated water supplies are delivered, ceteris paribus, than when increasing the probability that the crop receives full net irrigation requirement in the study region.Resource /Energy Economics and Policy,