For the last several decades, ecologists have known that heavier stable isotopes become more enriched in a consumer than in the food they eat, and have agreed that they increase by a standard additive factor
Estuarine Research Laboratory -- tended to have an acidic pH, Rudd says it's possible that sulfates may represent yet another additive factor
contributing to the methylmercury problem in regions beset by acid rain.
Are race, gender and sexual orientation additive factors
to be treated cumulatively in judging oppression?