With the increasing popularity of collaborative systems like social networks, the risk of data misuse has become even more critical for users. As a consequence, there is a growing demand for solutions to properly protect data created and used within these systems. Enabling collaborative specification of permissions, while ensuring an appropriate levels of control to the different parties involv...

The use of space by predators in relation to their prey is a poorly understood aspect of predator-prey interactions. Classic theory suggests that predators should focus their efforts on areas of abundant prey, that is, prey hotspots, whereas game-theoretical models of predator and prey movement suggest that the distribution of predators should match that of their prey's resources. If, however, ...

We study the level and severity of asset poverty, the characteristics of asset-poor households, the trends and persistence of asset poverty, and the role of major lifetime events affecting transitions in and out of asset poverty. We find that, contrary to a sharp decline in the official measure of poverty, which is based on income, the asset poverty rate barely changed over the 1984–99 period a...

Demain, A. L. (Merck Sharp & Dohme Research Laboratories, Rahway, N.J.), I. M. Miller, and D. Hendlin. Production of extracellular guanosine-5'-monophosphate by Bacillus subtilis. J. Bacteriol. 88:991-995. 1964.-Wild-type Bacillus subtilis colonies were found to feed purineless mutants. A strain with high feeding capacity was selected for study, with a guanineless mutant of B. subtilis used as ...

We report high resolution simultaneous measurements of electrical conductance and force gradient between two sharp gold tips as their separation is varied from the tunneling distance to atomic-size contact. The use of atomically sharp tips minimizes van der Waals interaction, making it possible to identify the short-range metallic adhesion contribution to the total force.