Letters to the Editor

19041

I think this article ignored the major reason that large particles rise to the surface. The laws of inertia and momentum indicate that larger particles don’t react as quickly as smaller particles do at the end of each back-and-forth shake of the container. This means there is a force for relative motion between different-sized particles. […]

18977

The occurrence of underflows or hyperpycnal currents originating from the mouth of the Salinas River should be no surprise, given the long-known riverine bathometric feature existing between the river and Monterey Canyon. The river has a high sediment load, so if these currents weren’t present, sediments from the Salinas River would settle on the continental […]

19040

I enjoyed your timely article. Conspicuously absent, however, was any mention of the possibility that the disease is a vascular disorder with neurodegenerative consequences, rather than the other way around. The involvement of several dozen risk factors for Alzheimer’s disease that all reduce or impair cerebral perfusion in the Alzheimer’s brain adds ammunition to this […]

19039

For a few unfortunate people, choline has a dark side. An inborn error of metabolism, trimethylaminurea, causes them to smell like rotting fish when they eat high-choline foods. Sara D. Brown Clinton, N.J. Good point. New labeling that identifies foods rich in choline should help people with trimethylaminurea avoid those foods. –J. Raloff As a […]

19033

The article states that a generic beta-blocker, when administered to patients who have suffered severe injury, was shown to reduce the common muscle-wasting condition known as hypermetabolism. Has this technique ever been considered for or shown effective in reducing inactive muscle wasting, as would occur in a long-term space voyage? Dwain L. Beaver Dayton, Ohio […]

19032

A Canadian nurse I know is working in Mt. Selinda, Zimbabwe. She is currently designing her dissertation, in which she will interview local women in an attempt to understand their perspectives on health and how to prevent HIV infection and AIDS. When I read your article on stigmas’ harm to public health , I e-mailed […]

19031

I found the article on Welwitschia enthralling–it made me want to set off for the Namibian desert straightaway! The author mentions that a local name for the plant is “long-haired thing,” but an even more evocative and picturesque one is the Afrikaans tweeblarkanniedood (two-leaf-cannot-die). Darwin was fascinated when he learned of Welwitschia and its extraordinary […]

19025

Researcher Mark Goodwin’s conclusion that a hollow base to an animal’s horn greatly diminishes its strength, and hence its utility in defense or dueling, begs for an engineering analysis. In tension, compression, and torsion about the axis of symmetry, most of the strength of a cylindrical structure comes from the walls, not the interior. If […]

19018

Couched in language peppered with mays, the article suggests that we are all being poisoned with PBDEs from sewage sludge applied to farmland. However, sludge with high concentrations of volatile organics isn’t qualified in most jurisdictions of which I am aware for land application. It’s usually sent to a landfill or incinerated. Couches and chair […]

19017

Thank you for your update of the antics of those madcap scientists who continue to very creatively search for “dark matter.” Their frantic quest seems more and more like a comedy of the absurd. Exotic theories such as of “cold dark matter” have now been joined by desperate, contrived fantasies of “self-interacting” and “just warm […]

18940

In your article you refer to imploding “air bubbles” that are produced by shrimp. However, these cavities, which are formed by cavitation, are filled with water vapor, not air. As the shrimp claws move rapidly through the water, a low-pressure area is formed behind the claws. If the pressure is below the vapor pressure of […]

18962

I just read the article and I’m dying to know what motivated the patient to undergo such an experimental (transatlantic) form of an otherwise routine surgery. Any info available? Henry Jones Baton Rouge, La.Her doctors say the patient was simply interested in advancing medical science and that she knew that several surgeons were standing by […]