Letters.

A hole in the analysis

The geographical area covered by the seasonal ozone depletion over the Antarctic seems to have been confused with the depth of this temporary loss ("Ozone hole is smaller than last year," SN: 10/23/99, p. 270). The size of the ozone hole is defined by the margins of the polar vortex, a low-temperature, wind-driven, climatic feature. While the actual loss of stratospheric ozone isolated within this vortex may be the result of ozone-destroying chemicals (chlorine, bromine, [N.sub.2] O), the area over which the ozone hole develops is not. NASA satellite data show that the area covered by the vortex has already shrunk at least twice in the past 20 years, even though ozone-depleting chemicals were still rising globally.

Thus, if the ozone hole starts to "shrink" in both size and depth, the shrinkage may be because of climatic factors, not necessarily because ozone-depleting chemicals have stopped rising.

Kenneth M. Towe Smithsonian Institution Washington, D. C

Barbarians at the tailgate 

In the article "Neandertals show staying power in Europe" (SN: 10/30/99, p. 277), anthropologist Fred H. Smith "was floored ... that there was a good deal of genetic exchange between Neandertals and modern humans." Obviously, Smith has never been on the beltway during rush hour.

Doug Hilton Huntsville, Ala.

The article suggests that the discovery of late Neandertals in Europe supports the idea of genetic interchange between modern humans and Neandertals. On the contrary, if there was much genetic interchange, the two populations would have merged into a single hybrid population after several thousand years. For the bones to be recognizably Neandertal after several thousand years of contact, genetic interchange must have been quite limited.

Stanley Friesen Lakewood, Calif.

Smith et al. do argue that the two populations evolved into a hybrid population. They use the term Neandertal as a convention to refer to fossils with particular features traditionally assigned to that group. --B. Bower

Look deeper into gay suicides

In "Social factors may make gay men suicidal" (SN: 10/23/99, p. 261), Richard Herrell's finding comes as no surprise. I suggest that scientists who research this topic not only interview gay men who have attempted suicide, but also their parents and siblings with respect to their attitudes toward their gay relatives.

Francis Leung Atlanta, Ga.

When a country allows the murder and marginalization of people based on sexual orientation, as happens routinely in the United States, it is not unusual that the targets internalize the hate and attempt suicide. Rather than presenting sociological findings that restate the obvious, it is long past time for studies that will determine effective ways to counter prejudice and ignorance-based hate.

Andrew Dorph Eldred Boze Washington, D. C