The Evolution of Hominid Bipedalism

Paleoanthropologists mark the divergence between apes and hominids with the adaptation ofbipedalism five to six million years ago. In this paper, I argue that while the first upright hominids occurred in this time frame, the process ofbecoming a fully efficient biped took much longer and was not complete until Homo erectus at 1.8 million years ago. To provide context to the puzzle ofhow and why our ancestors evolved upright walking, I examine many of the prevailing theories ofbipedal origins, including the aquatic ape hypothesis, the heat hypothesis, and the carrying hypothesis

Medium effects in K^+ nucleus interaction from consistent analysis of integral and differential cross sections

Self consistency in the analysis of transmission measurements for K^+ on several nuclei in the momentum range of 500-700 MeV/c is achieved with a "t_{eff}(rho)rho" potential and new results are derived for total cross sections. The imaginary part of the t_{eff} amplitude is found to increase linearly with the average nuclear density in excess of a threshold value. This phenomenological density dependence of the K^+ nucleus optical potential also gives rise to good agreement with recent measurements of differential cross sections for elastic scattering of 715 MeV/c K^+ by Li^6 and C.Comment: 11 pages, RevTeX, 2 Postscript figures, submitted Phys. Lett.

All Source Analysis System (ASAS): Migration from VAX to Alpha AXP computer systems

The Jet Propulsion Laboratory's (JPL's) experience migrating existing VAX applications to Digital Equipment Corporation's new Alpha AXP processor is covered. The rapid development approach used during the 10-month period required to migrate the All Source Analysis System (ASAS), 1.5 million lines of FORTRAN, C, and Ada code, is also covered. ASAS, an automated tactical intelligence system, was developed by the Jet Propulsion Laboratory for the U. S. Army. Other benefits achieved as a result of the significant performance improvements provided by Alpha AXP platform are also described