News Scan Briefs; May 2009; Scientific American Magazine; by Chalres Q. Choi; Coco Ballantyne; David Biello; Philip Yam; John Matson; 3 Page(s)

As microchips shrink, the inescapable electronic buzz that emerges from thermal fluctuations, cross talk between wires and other sources can endanger their proper function. A way around that problem could be stochastic resonance, a phenomenon in which noise can boost a weak signal and improve a systems performance. Certain kinds of structures, such as a sensory nerve, will output a signal only when background noise is sufficiently high. Researchers at Arizona State University constructed logic gatescircuit elements that perform logic functions that behave in a similar way. When noise levels are low, the gates perform unreliably; however, at the kinds of noise levels expected for the smallest transistors, they work correctly. Such unusual, nonlinear behavior could help microchips get smaller. Moreover, altering certain applied voltages in the circuit can reconfigure the gate on the fly, thereby creating a morphing processor. Tune in to the March 13 issue of Physical Review Letters for more details.

The capability to seek out medicinal plants was thought to be limited to creatures with advanced brains; for instance, chimpanzees harboring intestinal worms swallow bristly leaves to scrape the parasites from their guts. Now researchers at Wesleyan University and their colleagues find that woolly bear caterpillars (Grammia incorrupta) also self-medicate when ill. Caterpillars infested with parasitic fly maggots ate roughly twice as much alkaloid (specifically, pyrrolizidine alkaloid) as uninfested ones; such toxins naturally exist in bloodroot and other caterpillar food plants. As a result, roughly 20 percent more of the infested caterpillars survived into adulthood as compared with infested caterpillars that did not munch on the medicine. The findings, the first known instance of invertebrate self-medication, appear in the March 10 PLoS ONE.