The NASA-IGES geometry data exchange standard

Described here are the data exchange efforts and plans supported by the NASA Steering Committee for Surface Modeling and Grid Generation. Current methods for geometry data exchange between computer aided design (CAD) systems and NASA computational fluid dynamics (CFD) analysis systems are tedious and induce errors. A Geometry Data Exchange Standard is proposed, utilizing a subset of an existing national standard titled Initial Graphic Exchange Standard (IGES). Future plans for data exchange standardization include all aspects of CFD data. Software systems to utilize this NASA-IGES Geometry Data Exchange Specification are under development

Carbon isotope ratios of Sterkfontein fossils indicate a marked shift to open environments c.1.7 Myr ago

Sterkfontein straddles a period in the Plio-Pleistocene in which the effects of global-scale climate shifts on continental environments and biota are not yet well understood. Reconstructions based on faunal indicators have suggested incremental shifts from relatively closed, mesic landscapes to open, arid environments at this time. We examined environmental shifts from ~2.5 to 1.7 million years ago (Myr) using a C3 / C4 index derived from 13C / 12C data on bovid fossils from Sterkfontein. Data for Member 4 and the Member 5 East infill indicate persistence of a wooded to moderately wooded environment until about 2.0-1.8 Myr. Data indicating a marked shift to open environments are observed only for the younger Member 5 West infill. We conclude that the major shift to open environments occurred near 1.7 Myr rather than at c. 2.5 Myr