Tuesday, September 08, 2009

Science News Roundup

Scientists create rogue microwave model useful for simulating rare events that emerge from random processes.
Eric Heller at Harvard University and various pals have studied rogue waves for some time. Today they show how microwaves propagating through a forest of scatterers which the team call a "quasi-two-dimensional resonator with randomly distributed scatterers, each mimicking an r^−2 repulsive potential".

The results are fascinating because they clearly show the rogue waves (or hot spots in microwave terms) appearing more often than conventional thinking (Rayleigh's law for the wave height distribution) allows. In fact the team says the probability in their set up of a rogue wave appearing is 15 orders of magnitude greater than Rayleigh statistics predict. They attribute the difference to ray refraction rather than to resonance effects as conventional thinking might suppose.

Mouse retinas contain cells that detect approaching objects, possibly providing an advance warning system.
While investigating mouse eye cells, Botond Roska at the Friedrich Miescher Institute for Biomedical Research in Basel, Switzerland, and colleagues noticed that one type behaved unusually in response to movement. Further analysis of this one kind of retinal cell revealed that it fired only when an object approached.

The researchers suspect that people have similar cells, which alert us to approaching objects faster than our brain cells can. "It's an alarm system that's as close to the front end of the organism as possible," says Roska. "If you left it to the brain to respond, it might be too late."

It could also be that these cells form part of the signal processing apparatus that enhances visual acuity.

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