Web edition: January 31, 2006
Print edition: February 4, 2006; Vol.169 #5 (p. 79)
"Sleep apnea could signal greater danger" (SN: 11/26/05, p. 349) says that "twice as many ... with sleep apnea had a stroke or died of that or another cause. ..." This sounds serious, but your readers can't correctly assign importance to "twice as many" because you omit numbers of deaths.
Among the 697 people with sleep apnea, 22 suffered strokes and 50 other people died of that or another cause during the study. Among the 325 people without sleep apnea, there were 2 strokes and 14 deaths from strokes or other causes.N. Seppa
The picture caption in "Ancient Grazers: Find adds grass to dinosaur menu" (SN: 11/19/05, p. 323) states, "This phytolith, which was extracted from fossilized dinosaur dung unearthed in India, indicates that the reptiles dined on grasses." I do believe that dinosaurs aren't classified as reptiles.
American Canyon, Calif.
Confusion in this area stems from the fact that not all ancient reptiles were dinosaurs. But dinosaurs were a class of reptiles, set apart from others by their postures and their hip structures.S. Perkins
The evidence at best is fuzzy for bee recognition of faces ("Face Time: Bees can tell apart human portraits," SN: 12/3/05, p. 360). Both sugar water and quinine have unique odors that are probably readily recognizable by bees. And what do the feeders look like in the bee spectral range?
Jacques M. Dulin
For the test of bees' face recognition, the researchers used empty, identical feeders to avoid just such clues.S. Milius
While it is extraordinary that an unprotected insect larva survives gut passage ("When Worms Fly: Insect larvae can survive bird guts," SN: 12/10/05, p. 373), it is not the first demonstration that insects may be carried inside of birds. The larvae of phytophagous wasps living inside the seeds of the multiflora rose pass unharmed through the guts of mockingbirds.