CVT/GPL phase 3 integrated testing

The hardware for 20 candidate shuttle program life sciences experiments was installed in the GPL and experiments were conducted during a 5-day simulated mission. The experiments involved humans, primates, rats, chickens, and marigold plants. All experiments were completed to the satisfaction of the experimenters. In addition to the scientific data gathered for each experiment, information was obtained concerning experiment hardware design and integration, experiment procedures, GPL support systems, and test operations. The results of the integrated tests are presented

Mandatory seat belt laws in eight states: a time-series evaluation

We examined state-specific and aggregate effects of U.S. legislation requiring the use of seat belts among front-seat motor vehicle occupants. Effects of compulsory seat belt use on the number of occupants fatally injured in traffic crashes were examined in the first eight states adopting such laws. Monthly data on crash fatalities between January 1976 and June 1986 were analyzed using Box-Tiao intervention analysis time-series methods. Because the new laws apply only to front-seat occupants, front-seat occupant fatalities were compared with: (1) rear-seat fatalities; (2) nonoccupant fatalities (motorcyclists, pedalcyclists, pedestrians); and (3) fatalities among front-seat occupants in neighboring states without compulsory seat belt use. Exposure to risk of crash involvement was controlled by analyzing fatality rates per vehicle mile traveled. Results revealed a statistically significant decline of 8.7% in the rate of front-seat fatalities in the first eight states with seat belt laws. The fatality rate declined 9.9% in states with primary enforcement laws and 6.8% in states with secondary enforcement only. Rates of rear-seat and non-occupant fatalities did not change when the belt laws were implemented.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27229/1/0000236.pd

Topology and Wilson lines: global aspects of the double copy

The Kerr-Schild double copy relates exact solutions of gauge and gravity theories. In all previous examples, the gravity solution is associated with an abelian-like gauge theory object, which linearises the Yang-Mills equations. This appears to be at odds with the double copy for scattering amplitudes, in which the non-abelian nature of the gauge theory plays a crucial role. Furthermore, it is not yet clear whether or not global properties of classical fields - such as non-trivial topology - can be matched between gauge and gravity theories. In this paper, we clarify these issues by explicitly demonstrating how magnetic monopoles associated with arbitrary gauge groups can be double copied to the same solution (the pure NUT metric) in gravity. We further describe how to match up topological information on both sides of the double copy correspondence, independently of the nature of the gauge group. This information is neatly expressed in terms of Wilson line operators, and we argue through specific examples that they provide a useful bridge between the classical double copy and the BCJ double copy for scattering amplitudes.Comment: 31 pages, 4 figures. Some minor corrections have been implemente

The Weyl double copy from twistor space

The Weyl double copy is a procedure for relating exact solutions in biadjoint scalar, gauge and gravity theories, and relates fields in spacetime directly. Where this procedure comes from, and how general it is, have until recently remained mysterious. In this paper, we show how the current form and scope of the Weyl double copy can be derived from a certain procedure in twistor space. The new formalism shows that the Weyl double copy is more general than previously thought, applying in particular to gravity solutions with arbitrary Petrov types. We comment on how to obtain anti-self-dual as well as self-dual fields, and clarify some conceptual issues in the twistor approach