Web edition: March 5, 2007
Print edition: March 10, 2007; Vol.171 #10 (p. 159)

Cosmic cling

At least on Earth, rock impacts result in charging of the particles ("Rocky Finding: Evidence of extrasolar asteroid belt," SN: 1/6/07, p. 5). In space, wouldn't this have a great effect on the motion of the rocks?

Stuart Hoenig
Tucson, Ariz.

According to researchers, it's true that the electrostatic charging of space dust and rocks may affect the motions of small particles. However, little is known about the influence of this on dust clumping or on the formation of molecular hydrogen.—R. Cowen

Double dose?

Regarding "Folic Acid Dilemma: One vitamin may impair cognition if another is lacking" (SN: 1/13/07, p.19), would it be feasible for the government to require both folate and vitamin B₁₂ in grain products?

Nancy Power
Altadena, Calif.

Researchers say that such double fortification is theoretically possible. However, vitamin B₁₂ is more expensive than folate, and it turns flour pink.—B. Harder

Watch your fingers

Regarding "Digital Fingerprints: Tiny behavioral differences can reveal your identity online" (SN: 1/13/07, p. 26), Morse code "fist" analysis can easily be defeated by a software buffer that conforms the intervals between all types of strokes. Actual Morse buffers are already in regular use among ham operators. "Writeprints" can also be defeated. "Clickprints" aren't as easy to conceal, perhaps, but some clever software designer will devise a foil for them too.

Paul Schlueter III
Dallas, Pa.

Half empty

Although "almost half" of the individuals came to agree that coerced eating-disorders treatment was justified, I find it irresponsible that the study seemingly ignored the identification of potentially long-lasting negative effects on more than half of coerced clients ("Starved for Assistance: Coercion finds a place in the treatment of two eating disorders," SN: 1/20/07 p. 38). Those people may come away with less hope that such treatment can ever be of help to them.

Robert C. Johnson
Bend, Ore.