Mathematical Digest
Short Summaries of Articles about Mathematics in the Popular Press "From Elton to Mathematics and Back Again," by Dave Raffaelli. Science, 10 May 2002, pages 10351036. Raffaelli writes of work in ecology by Neutel et al ("Stability in RealFood Webs: Weak Links in Long Loops," page 1120 of the same issue) that blendsnew mathematical models with traditional ideas like food webs. The researchersused a concept called trophic loops"closed chains representing interactionstrengths between adjacent species in a food chain" to explain stability insome complex soil ecosystems. Interaction strengths are numbers between 0 and 1that represent effects of a predator on prey or prey on a predator. Theconclusion of the study is that stable systems have long loops of weakinteraction strengths.  Mike Breen
