This article gives an overview of a normative theory visual receptive fields. We describe how idealized functional models early spatial, spatio-chromatic and spatio-temporal fields can be derived in principled way, based on set axioms that reflect structural properties the environment combination with assumptions about internal structure vision system to guarantee consistent handling image repr...

This paper discusses both the opportunities for and the challenges associated with integrating economics and ecology in the study of ecosystem services. We distinguish between integration in positive versus normative analysis. There is rapid growth in positive research that combines the two disciplines to provide insight and better understanding of the bidirectional linkage between economic and...

Scholars have long noted how migration streams, once initiated, obtain a self-feeding character. Studies have connected this phenomenon, called the cumulative causation of migration, to expanding social networks that link migrants in destination to individuals in origin. While extant research has established a positive association between individuals’ ties to prior migrants and their migration ...