SN Online SN Online Share this:EmailFacebookTwitterPinterestPocketRedditPrint By Science News January 24, 2013 at 9:58 pm MATH TREK Economists say auction-based purchasing could create market chaos. See Julie Rehmeyer’s column “Devil is in the details of a new Medicare plan to buy medical supplies.” P. Mercier et al/Nature Biotechnology 2012 SCIENCE NEWS FOR KIDS Research in guinea pigs finds a way to power small electronic devices using a voltage difference in the inner ear. Read more in “Your head’s battery.” RANDOMNESS Tom Siegfried’s column “Maybe there’s a way to find out if reality is a computer simulation” explores how computers describe the universe.