With the aid of numerical experiments we examined the dynamical stability of fictitious terrestrial planets in 1:1 mean motion resonance with Jovian-like planets of extrasolar planetary systems. In our stability study of the so-called "Trojan" planets in the habitable zone, we used the restricted three-body problem with different mass ratios of the primary bodies. The application of the three-b...

Spontaneous interaction among humans and things in pervasive computing systems is often based on the spatial outreach to which an entity can interact with another entity, often referred to as ”zone of interaction”. Usually technological sensors for proximity and distance, like radio, ultrasound or microwave, are used to perceive and track the presence, activity and utterance of entities in the ...

THE EDITORIAL BY ROSAMOND NAYLOR, “Offshore aquaculture legislation” (8 Sept., p. 1363), suggests that the motivation for moving aquaculture into the open ocean is that “marine f ish farming near the shore is limited by state regulations.” Although unworkable regulations may exist in a few states, in the larger scheme this is irrelevant. Of the offshore aquaculture projects currently under way,...