Understanding how institutional changes within academia may affect the overall potential of science requires a better quantitative representation of how careers evolve over time. Since knowledge spillovers, cumulative advantage, competition, and collaboration are distinctive features of the...

Complex systems can be characterized by classes of equivalency of their elements defined according to system specific rules. We propose a generalized preferential attachment model to describe the class size distribution. The model postulates preferential growth of the existing classes and the...

Objective: To describe the changes in costs of care for HIV - positive patients in Italy after the spread of antiretroviral combination therapies (HAART). Methods: Five thousand four hundred and twenty - two patients from the I.CO.N.A. (Italian Cohort Naive Antiretrovirals) study were followed...

In this paper, we investigate how underlying relevant technological conditions induce distinguishable patterns of change in industry structure and evolution. A mapping is detected between the specific nature of problem decompositions and research techniques at the micro level of knowledge bases,...

The size distribution of business firms is explained using number and size of firms' constituent components. It is a lognormal distribution multiplied by a stretching factor which can lead to a Pareto upper tail. This result is confirmed empirically

Public research systems in the United States and Europe are often compared with respect to their divergent levels of involvement in the private economy. The U.S. research system, with its mix of both public and private institutions, has long played a significant role in conducting research that...

We introduce a model of proportional growth to explain the distribution Pg(g) of business-firm growth rates. The model predicts that Pg(g) is exponential in the central part and depicts an asymptotic power-law behavior in the tails with an exponent z=3. Because of data limitations, previous...

This paper shows how specific technological and relational regimes have shaped the growth of the network of R&D collaborative agreements in pharmaceuticals in the 1990s. Our analysis reveals the existence of a complex set of regimes of firm growth within the network, providing additional...

This work studies the processes of growth of the worlds top 150 pharmaceutical firms, on the grounds of an original database which also allows disaggregate analysis at the level of single therapeutic classes and chemical entities. Our findings show that the industry - whose long - term evolution...