Letters from the July 21, 2007, issue of Science News

Quantum leak?

Perhaps there need not be “degrees of quantumness” (“Degrees of Quantumness: Shades of gray in particle-wave duality,” SN: 5/12/07, p. 292). As the beams pass increasingly closer to the surface, the plate will induce a small (but increasingly larger) spread of energies (hence wavelengths) in the electrons within the beam, possibly explaining the “smearing out” of the fringes in the interference pattern.

Michael D. Meloy
Santa Barbara, Calif.

Peter Sonnentag of the University of Tübingen in Germany says that the loss of energy is tiny: less than 0.1 percent. Moreover, Sonnentag says that the change in energy could account for a change only in fringe spacing, not in fringe visibility.—D. Castelvecchi

Good bugs, bad bugs

Kudos for “Our Microbes, Ourselves” (SN: 5/19/07, p. 314). I think this holistic view of the microbe community—rather than investigating the single organism—offers a hopeful path to numerous insights for preventive measures for optimum health.

Terry Moore
Corvallis, Ore.

The article states, “Mice bred to be obese had a larger proportion of Firmicutes and a smaller proportion of Bacteroidetes than their lean counterparts did.” Later, you wrote, “Sure enough, as individuals of both groups lost weight, the proportion of Firmicutes in their guts rose, while the proportion of Bacteroidetes dropped.” On the surface, this seems contradictory.

Mike Speciner
Acton, Mass.

The second quoted passage from the story had it backward. It should have read, “The proportion of Bacteroidetes in their guts rose, while the proportion of Firmicutes dropped.”—A. Goho

Tea to a fit

The fact that various teas contain beneficial antioxidants is well-known (“Slimming on oolong,” SN: 5/19/07, p. 318). Many claim to be slimming. Is it only oolong that inhibits fat absorption, and, if so, why?

James C. Matthews
Coral Springs, Fla.

Lauren Budd of the University of California, Davis works only with oolong. She acknowledges that research by others has shown a slimming effect from other teas. However, most of that research hasn’t focused on oolong, the tea that traditional Chinese medicine has linked with dieting.—J. Raloff