Stephen Simpson

I. FACTORIALLY DESIGNED EXPERIMENTS VS RESPONSE SURFACE METHODOLOGYA conventional experimental approach investigates the effects of one independent variable while keeping all other variables constant. This approach faces two challenges (i) it is only valid when the underlying principles linking cause and effect are known with some certainty; (ii) variables may interact with each other and the magn ...

I. THE GEOMETRY OF NUTRITION In GF models, individual animals, foods and their interactions are represented graphically in a geometric space defined by two or more food components (for a comprehensive review see Simpson and Raubenheimer, 2012). Foods are represented as vectors through nutrient space at angles determined by the balance of the component nutrients they contain (nutritional rails), a ...