Consider a pair of plane straight-line graphs whose edges are colored red and blue, respectively, and let n be the total complexity of both graphs. We present a O(n logn)-time O(n)-space technique to preprocess such a pair of graphs, that enables efficient searches among the red-blue intersections along edges of one of the graphs. Our technique has a number of applications to geometric problems...

Optimal escape theory generally assumes that animals have accurate information about predator distance and direction of approach. To what degree such information is available depends not only on the prey's sensory capabilities but also on its behaviour. The structure of behaviour can strongly constrain or support the gathering of information. The ability of animals to collect and process inform...

The navigation of autonomous mobile machines, which are referred to as robots, through unknown terrains, i.e., terrains whose models are not a priori known is considered. We deal with point-sized robots in twoand three-dimensional terrains and circular robots in two-dimensional terrains. The two-dimensional (three-dimensional) terrains are finite-sized and populated by an unknown, hut, finite, ...

The usual conclusion in the literature is that sunspots reduce welfare because of the agents’ risk aversion. However, if sunspots can lead to escape from an inferior steady state (poverty trap), this conclusion does not necessarily hold. Escaping trajectories can have much higher welfare than those remaining in the poverty trap. The ex—post welfare effect can be positive for initial conditions ...

Femtosecond photoionization studies in neat protio and deuterio water at room temperature have been performed. The rate of appearance of the solvated electron is slower in D,O than in H,O, consistent with the predictions of continuum theories. The observed geminate recombination dynamics of the cation-electron pair is also isotope dependent. The recombination time is slower in D20 and the fract...

Sensory exploitation occurs when signals trigger behavioral reactions that diminish the receiver's fitness. Research in this area focuses on the match between the signal's form and the receiver's sensitivity, but the effect of habitat on interspecific sensory exploitation is rarely addressed. Myioborus redstarts use conspicuous wing and tail displays of contrasting black-and-white plumage patch...