Letters from the January 14, 2006, issue of Science News

Alcohol calculus

“A toast to thin blood” (SN: 11/12/05, p. 317) says, “the blood of people who consume 3 to 6 drinks weekly was less likely to clot in a test tube than was the blood from nondrinkers.” I wonder if there is a rebound effect that could make the blood of new abstainers even more likely to clot than that of regular nondrinkers. In other words, if one abruptly stops drinking, is that a temporary added risk?

Tom Paskal
Montreal, Quebec

This is an interesting idea, but it is not one that the authors of the current study pursued.—C. Brownlee

Albedo: Abetted or abated?

“Runaway Heat” (SN: 11/12/05, p. 312) makes the point that shrub intrusion into tundra reduces albedo, the percentage of reflected light, but doesn’t report actual impact on ground temperature. Albedo itself is not a good indicator of waste heat. Much of the extra absorbed sun energy is used by the shrubs for photosynthesis and the fixing of carbon and thus is unavailable for heating the environment. I hope this detail was addressed in the field experiment with accurate ground and ambient-air temperature measurements. The effect of the albedo alone may not tell the whole story.

Bob Pettit
Corvallis, Ore.

Some experiments suggest that even though the shrubs sequester carbon, the soil beneath loses even more, resulting in a net loss of carbon.—S. Perkins

Flying spaghetti mastered?

I would venture to suggest the reason that the pasta-fragmentation process stops (“That’s the Way the Spaghetti Crumbles: Physicists solve a vexing kitchen puzzle,” SN: 11/12/05, p. 315). Once the strand breaks, it becomes x number of new strands, each of which is still vibrating at some residual frequency and amplitude. The mass, diameter, and length of each resultant strand might determine the wavelength and amplitude necessary to break it. If a strand has gotten small enough that the amount of energy contained by the frequency and amplitude of the residual vibration are too low to cause enough stress on the strand, it doesn’t break. My wife has put me on notice that any further experimentation is strictly off limits in the kitchen, so I will leave the mystery to the experts.

Jim Longley
Allen, Texas