Letters to the Editor

19189

I feel the need to comment on the misconception that trisomies of other than chromosome 21 don’t survive birth. I have a friend whose daughter is a trisomy 18 and just celebrated her 19th birthday and other friends whose children with trisomies are nearing their teenage years. My own son, a trisomy 13, lived for […]

19148

Newton derived theories about gravity by studying stationary or very slowly moving objects. Laboratory measures of G performed since share this fundamental approach. While this may accurately measure G, any possible relative velocity dependence to this constant or to the force of gravity goes undetected. Determining that force involves only the masses, the separation, and […]

19188

Your article perpetuates a common error regarding pond aquaculture when it states, “These systems all rely on large volumes of clean water flowing to the fish and carrying waste away.” In the catfish industry (the largest pond-culture venture in the United States), ponds are only emptied for renovation once every 10 to 20 years, and […]

19187

After reading this article, I may have an answer for why a routine chest X ray indicated prominent scar tissue on my lungs even though I have never been a smoker during my 61 years. For the past 15 years, since a heart attack, I have jogged or ridden a bicycle for approximately an hour […]

19147

I am concerned about this article. It addresses the mass of fissile materials needed to “make a bomb,” yet it’s clear that the critical masses given–10 kilograms for plutonium-239, 50 kg for uranium-235, and 60 kg for neptunium-237–are for bare spheres with no neutron moderation, reflection, or other factors contributing to going critical. Consider that […]

19186

In your article, a spinning coin’s motion is explained by the existence of an air cushion between coin and tabletop. If this is indeed the case, then I would expect coins to do something quite different in a vacuum. What do they do? Richard Chambers Charlotte, N.C. H. Keith Moffatt offers an explanation for the […]

19146

Concerning the Apollo rocket’s third stage returning to Earth orbit: How did the researchers determine the source to be Apollo 12, since there were six other Apollo moon missions? Did they use some fancy orbital mechanics along with statistical probability? George RichesonBrenham, Texas Yes, they did, and the orbit matched. Also, the researchers found no […]

19185

In response to this article, I’d like to ask why is it that on our campus, native swamp maples growing within 30 feet of one another display totally different leaf color? While I appreciate them aesthetically, I’d also like to understand why their anthocyanin production is different. Marcia WalshNorth Andover, Mass. According to David Lee […]

19145

Your recent article on the exact nature of bubbles in beer and other beverages keyed an old memory. In Cleveland, during Christmas, one brewery used to bring out its holiday oddity for sale. They billed it as “the pale stale ale with the foam on the bottom . . . and the top!” There really […]

19184

In this article, I was surprised to read that chimeras harboring a mutation are not medically useful. Consider the value of cytokine-receptor mutations in humans, with respect to HIV. It’s likely that introducing some genetic mutations can inhibit viruses or bacteria in a host. Freda Wasserstein Robbins New Jersey City University Jersey City, N.J.

19029

Your readers need not wait to do less crying in the kitchen. All you have to do is put the onions in the refrigerator for a half hour or in the freezer for 10 minutes. Daniel F. BarightLebanon, Mo. Another solution is to do the chopping outside. I have found that more turbulent, outside air […]

19028

The picture of the mummified dinosaur was amazing and a bit spooky. It is a great find. Patrick LeaheyGeneva, N.Y.