Letters

Iridescent shortcut
I was disappointed with your diagram of a Morpho wing in the June 7 issue (“How they shine,” SN: 6/7/08, p. 26). Rather than properly show different wavelengths of light interfering differently, you instead chose to cheat by keeping the wavelength the same in the two pictures and reversing the phase of the reflection from “Surface 2.” By doing this, you failed to illustrate the physics and lost an opportunity to elucidate it to the reader, who may instead come away with confusion or even an incorrect understanding of the phenomenon.
Mike Speciner, Acton, Mass.

Mature, or just dead
The article “Forest invades tundra” (SN: 7/5/08, p. 26) was very interesting, informative and disturbing. But just one note on the photo caption on Page 26. The tree indicated as “mature” may more accurately be described as dead. It appears that two inches of bark and sapwood have been burned off, leaving a well-charred inner section. If the back side of the tree does not miraculously have a nice strip of living bark attached, then that “mature tree” is surely dead. Thanks for a great science magazine.
Tom Prunier, Arlington, Va.

Voice from the past
Now that I’ve seen the first four of the new Science News biweekly issues, I am way overdue in offering my congratulations. The new layout and design is crisp, professional and attractive; the content is as good as ever; and the whole product is more appealing. I also like the addition of your editor’s column, something I think adds both a personal and professional touch and brings readers into your plans and ideas, as well as several other new, succinct features (“Science Stats” and “Scientific Observations”). Science News issues have long been all over our house, despite my best efforts to file them all chronologically. My family has grown up with it. My wife repeatedly exclaims about how dramatic and appealing the new format is. My grandsons, one a budding scientist/engineer, who had a gift subscription from me to the old format, like the new one even better. Any misgivings I may have had a year ago upon hearing of the possibility of reducing the frequency to once every two weeks have been decidedly put to rest. The trade-off to larger, less frequent issues is a winner, in my view.
Kendrick Frazier, Albuquerque, N.M.

Editor’s Note: Kendrick Frazier served as editor of Science News from 1971 to 1977. He is now editor of Skeptical Inquirer: The Magazine for Science and Reason.

Simpleminded voters
In modeling there are several phases. Once the model is constructed, it is validated, which means its predictions are compared to real-world data. If there are discrepancies, they are investigated and the model is revised to make the predictions close enough to actual data. The validation steps can be very important since they basically point out the parts of the model that were not thought of. The modeling described in “Simpleminded voters” (SN: 7/5/08, p. 22) appears to have skipped the validation steps. It reports discrepancies between predicted results and actual results with no explanation of the discrepancies or attempt to revise the model. It could be, for example, that voters think that behavior with reporters is an important predictor of ability to negotiate with world leaders. Voters may consider that an important factor in picking a candidate, not an excuse to avoid looking at other data. There are several other factors that could come into play, and investigating the discrepancies might tell more about the voting process.
Ivan Mann, Hoover, Ala.

Certainly the argument that voters are more likely to vote properly when they ignore the overload of information and simply follow the party or organizational line when they cast their ballots has flaws. This is one case where statistics lie, with educated voters expressing their opinion in the voting booths based not only on information but also on logic. Average voters have certain issues that are of top priority but may be in opposition to their political party or organization. Certainly in such a case, they should vote with their consciences and not follow the dictates of a political party. Incidentally, that is what makes each election a horse race.
Nelson Marans, Silver Spring, Md.

Kudos for epigenetics article
I would like to congratulate Tina Hesman Saey on her feature article about epigenetics (“Epic genetics,” SN: 5/24/08, p. 14). She has conveyed, most lucidly, the fundamentals of a complex concept. As a science writer she has admirably inserted herself as a translator for those of us outside that particular area of biology. Many thanks and keep up the good work.
Jim Dunn, Warminster, Pa.

Science and government
Although I am in complete agreement with Steven Hyman in his June 7 column (“U.S. science policy needs to heed global realities,” SN: 6/7/08, p. 32), he barely scratches the surface with his observations on stem cell research.
The depth of the problem caused by the impact of Bush administration ideology on the scientific community reaches earth science (global warming), human biology (“life begins at conception”), health (“abstinence only” demands, etc.), ecology (mercury, arsenic, carbon dioxide, etc.) and the variety of disciplines involved with primary research into alternative power sources. And even this is a small sample of the ongoing antiscience offensive to which we’ve all been subjected. This is not just about advancing pet projects at the expense of others, it’s about sacrificing the future of our nation, and the world, at the altar of ignorance and narrow-minded, money-power ideology. After eight long, dreadful years of voodoo science and the rejection of the best the world’s scientific minds have to offer, is it any wonder the leading edge the United States once had has been dulled? Is it any wonder today’s new college students are avoiding the scientific endeavor?
Rev. Bud Adams, Central Square, N.Y.

Steven Hyman needs to heed global history. Wealthy countries became wealthy before their governments spent much on research. Conversely, let us recall that the resources lavished on science by the Soviet government proved of little benefit to its citizens.
Governments are not very effective allocators of resources, including precious intellectual talent. Firms and philanthropists operating in a free market are more likely to sponsor research of timely value, less likely to squander massive resources on premature exploration of scientific exotica.
The U.S. government does not spend too little on research. It spends far too much.
Allan Walstad, Johnstown, Pa.

Vapor breath
Our breath is more than 99 percent water? (“Every breath you make tells of all your aches,” SN: 7/5/08, p. 5.) No wonder I’m so thirsty! But I’m curious — how do our bodies use all that nitrogen we breathe in but apparently not out?
Bill Ossmann, Acton, Mass.

To address your question, I contacted John Hunt, a respiratory medicine specialist at the University of Virginia Children’s Hospital in Charlottesville, and this is his response: “Water vapor makes up more than 99 percent of the volume of the liquid exhaled breath condensate collected using current techniques — which do not condense nitrogen out of gas phase. Nitrogen gas concentrations are similar in inhaled and exhaled breath, and there is no net consumption of nitrogen by the body. Water loss in exhaled breath, although less than urinary water loss, is indeed a major reason why people get thirsty.” —Rachel Ehrenberg