In this paper we study some mechanisms that block a rapid diffusion of technological progress from advanced to underdeveloped countries. In order to accomplish this task we focus on two approaches that challenge the view that technological gaps between rich and poor nations are diminishing.

The aim of this paper is to examine how the service sectors contribute to labor productivity in the economy as a whole, as well as each of the sectors in particular, using the notion of vertically integrated sector developed by Pasinetti (1973). The studies focused on structural changes and...