We prove that the Random-Edge simplex algorithm requires an expected number of at most 13n/ √ d pivot steps on any simple d-polytope with n vertices. This is the first nontrivial upper bound for general polytopes. We also describe a refined analysis that potentially yields much better bounds for specific classes of polytopes. As one application, we show that for combinatorial d-cubes, the trivi...

We prove that the Random-Edge simplex algorithm requires an expected number of at most 13n/ √ d pivot steps on any simple d-polytope with n vertices. This is the first nontrivial upper bound for general polytopes. We also describe a refined analysis that potentially yields much better bounds for specific classes of polytopes. As one application, we show that for combinatorial d-cubes, the trivi...

In high-energy collisions (E,,, > 50 MeV/nucleon) the eikonal approximation provides a transparent description of heavy-ion exchange reactions. The formalism is applied to the reaction ‘3N(‘3C, 13N)13C at 70 MeV/nucleon. The relative contributions of pionand rho-exchange are determined. It is found that heavy-ion reactions are more sensitive to the one-pion exchange component of the interaction...

Recent advances in SPECT technology including cadmium-zinc-telluride (CZT) semiconductor detector material may pave the way for absolute myocardial blood flow (MBF) measurements by SPECT. The aim of the present study was to compare K1 uptake rate constants as surrogates of absolute MBF and myocardial flow reserve index (MFRi) in humans as assessed with a CZT SPECT camera versus PET. METHODS A...

BACKGROUND Imaging reporter gene expression is useful for noninvasive monitoring of gene therapy. In this study, we imaged cardiac reporter gene expression in living rats using micro positron emission tomography (microPET). METHODS AND RESULTS Rats (n=10) underwent intramyocardial injection with 1x10(9) pfu of adenovirus carrying cytomegalovirus promoter-driving herpes simplex virus type 1 mu...

The content o f aromatic units in polym aleic acid (PMA) prepared by standard procedures is determined by C -13N M R and three different oxydation procedures. It is shown that all destructive oxydation procedures lead to an aromatic carbon content that is significantly higher than the aromaticity content expected from the method o f preparation and derived from the C-13 NM R spectra. It is conc...