Letters to the Editor

19168

I found this article quite fascinating. In 1973, my colleagues and I showed that rats would respond with the future in mind. Specifically, rats will make a response that results in one immediate electric shock, as long as that punished response is instrumental in avoiding five identical shocks programmed to occur 10 seconds later. It […]

19167

Just because chemical equipment can measure parts per trillion doesn’t necessarily mean that they have any biological significance. If you took one pill of Tylenol and dissolved in an olympic-size swimming pool, that would roughly be 1 part per billion. One part per trillion would be one pill in 1,000 swimming pools. My point is […]

19166

I read your article about bilirubin protecting cells from free radicals and possibly cancer and heart disease. People with Gilbert’s syndrome, which affects 5 percent of the population, have higher-than-normal amounts of bilirubin in their blood. Has any study been conducted to ascertain whether people with Gilbert’s syndrome have a lower incidence of cancer and […]

19165

“Waves,” or crenulations, occur not only on water icicles, but also in caves on dripstone and flowstone speleothems composed of calcite, epsomite, goethite, and even mud. All of these formations display “wavelengths” of around 1 centimeter. The origin of these crenulations is due not to heat, but to greater evaporation and carbon dioxide loss from […]

19193

I note with some incredulity that happiness (joy, elation) in some form is missing from the list of “basic” universal emotions, and even from the extended list of 9 or 10. Is happiness not considered a basic emotion? Did ancient Hindus not experience joy and hence not express it in dance? Or is happiness considered […]

19213

This article says that in cavitation, “bubbles form when falling pressure permits dissolved gases to pop out of solution.” A cavitation-vapor bubble is formed when the pressure drops below the vapor-liquid saturation pressure for the liquid. Dissolved gas bubbles will just give you a fizzy cola. A.J. McPhateBaton Rouge, La.

19212

It’s no surprise to find that the Borneo tree frog tunes into his tree hole. From the resonance of electron shells to the orbits of planets, stars, and galaxies, harmonic relationships define all of creation. Many frogs have external tympanic membranes that resonate to their tiny chirpings. This mechanism helps put entire ponds full of […]

19211

This article recommended shock absorbers and cushioned seats. Did this study survey what type of bikes the volunteers rode? Doug LandonSimi Valley, Calif. Study coauthor Ferdinand Frauscher notes that although most of the long-time bikers now use bikes with shock absorbers and padded seats, they almost all originally rode bikes with little or no padding […]

19210

Contrary to your article, animal cells do not possess “cell walls,” as suggested by “proteases are usually much smaller and don’t inhabit cell walls.” Plants have cell walls; animal cells are bound by a single lipid bilayer membrane. David Winialski Tallahassee, Fla.

19192

Your article shows hazy pictures from Great Smoky Mountains National Park and says the cause of the haze is “volatile organic compounds released by trees.” I’m the air-quality specialist in the park, and I know that 60 percent of the particle mass in the air is sulfate from power plants, not trees, and 80 percent […]

19203

Many people who are exploring the possible connection between childhood vaccines and autism claim that the culprit is not the vaccines themselves, but the mercury-containing preservative thimerosal. Does the Danish MMR vaccine contain it? Anne SealsSumner, Wash. Thimerosal has never been used in the MMR vaccine, either in the United States or in Denmark .–B. […]

19202

What is reported in this article is a new application of an old idea. In the 1950s and early 1960s, engineers would check a computer by setting a radio beside the central processing unit to pick up the electromagnetic signals put out by switching vacuum tubes and, later, transistors. By programming so that the switching […]