title: Sources of northeast pollution.
abstract: In the article, "Amplification and adaptation in regulatory and sensory systems" by D. E. Koshland, Jr., A. Goldbeter, and J. B. Stock (16 July, p. 220), the following errors should be corrected. On page 221, the ordinate on figure 1 was incorrect. The correct figure is given below. On page 223, in the first column, 23 lines from the bottom, the number 9 should be replaced by the number 7. [See Figure in the PDF file]
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D000397:Air Pollution; D008873:Mid-Atlantic Region; D008962:Models, Theoretical; D013431:Sulfates / Q000032:analysis*
chemical_list: D000393:Air Pollutants; D013431:Sulfates