Multiproduct Firms and Product Differentiation: a Survey.

We start the survey by reviewing the implications of horizontal and vertical product differentiation on market structure under the assumption of single-product firms. Then, we analyze the main results of the multi-product firm models, both when variants are assumed differentiated in vertical attributes only and when variants are assumed differentiated in two dimensions (vertical and horizontal). Finally, we review the empirical literature about the discrete-choice models of product differention.COMPETITION ; MARKET ; PRODUCTION DIVERSIFICATION

Multiproduct firms and product differentiation : a survey

We start the survey by reviewing the implications of horizontal and vertical product differentiation on market structure under the assumption of single-product firms. Then, we analyse the main results of the multi-product firm models, both when variants are assumed differentiated in vertical attributes only and when variants are assumed differentiated in two dimensions (vertical and horizontal). Finally, we review the empirical literature about discrete-choice models of product differentiation

Clinical xenotransplantation

Abstract: Two baboon liver xenografts transplanted to patients with B virus hepatitis supported life for 70 and 26 days but did not function optimally despite minimum or no histopathologic findings of overt humoral or cellular rejection in serial biopsies. However, there was evidence of complement activation in both cases, which in retrospect was thought to explain the unsatisfactory outcome. Strategies to deal with this problem are discussed. © 1994 Munksgaar