Monday, January 25, 2010

Self-Optimization

In [an] experiment, researchers led by Toshiyuki Nakagaki, of Hokkaido University in Sapporo, Japan, placed oat flakes (a slime mold delicacy) in a pattern that mimicked the way cities are scattered around Tokyo, then set the slime mold loose.After about a day, the slime mold had constructed a network of interconnected nutrient-ferrying tubes. Its design looked almost identical to that of the rail system surrounding Tokyo, with a larger number of strong, resilient tunnels connecting centrally located oats. “There is a remarkable degree of overlap between the two systems,” Fricker says.
The researchers then borrowed simple properties from the slime mold’s behavior to create a biology-inspired mathematical description of the network formation. Like the slime mold, the model first creates a fine mesh network that goes everywhere, and then continuously refines the network so that the tubes carrying the most cargo grow more robust and redundant tubes are pruned.

The behavior of the plasmodium “is really difficult to capture by words,” comments biochemist Wolfgang Marwan of Otto von Guericke University in Magdeburg, Germany. “You see they optimize themselves somehow, but how do you describe that?” The new research “provides a simple mathematical model for a complex biological phenomenon,” Marwan wrote in an article in the same issue of Science.

source: wired.com

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