Web edition: October 16, 2007
Print edition: October 20, 2007; Vol.172 #16 (p. 255)
Margit L. Bleecker appears to have discovered that those who score highly on reading tests also score highly on tests of memory, attention, and concentration ("How reading may protect the brain," SN: 8/18/07, p. 110). I don't find that highly surprising.
"Alien Pizza, Anyone?" (SN: 8/18/07, p. 107) reviews efforts to explain why certain biological molecules tend to be all right-handed (e.g., sugars) or left-handed (e.g., amino acids). An explanation might lie in the evolution of enzymes involved in their synthesis. For example, the fact that some organisms produce predominantly d-alanine could be explained by random mutations for the opposite enzyme rather than a modification of some physical molecular-pairing mechanism.
John E. Morris
The research described in "Road Bumps: Why dirt roads develop a washboard surface" (SN: 8/18/07, p. 102) draws sound conclusions. However, the context suggests the tests were done at constant speeds. I submit there is yet another cause. It has been my observation that washboarding occurs initially and primarily at areas where there is acceleration, such as coming out of curves and starting up inclines.
It's unfortunate that researchers don't look for previous studies before duplicating efforts of others. In January 1963, a Scientific American article describes the controlled experiments done by Dr. Keith B. Mather, using a powered turntable, which resulted in identical conclusions.
David A. Coats
The authors do not seem to have any real-world experience driving on dirt roads. I can attest that it is almost solely the materials that make up the road that determine whether or not it will develop washboards. Loose materials create washboard roads. Too much sand and gravel, without the appropriate amount of clay, or glue, and you get washboards.
David T. Allen