Innovation, Market Structure and Economic Growth

This paper presents a dynamic partial equilibrium model that endogenizes firms' investment decision on innovation: product innovation causes horizontal expansion growth, and process innovation causes vertical expansion growth. Market structure in different markets emerges as a consequence of different investment on innovation opportunities. Main variables that constrain this structure in a given market are the rate of scientific (basic) discoveries that permit innovation productivity, and the degree of substitution between varieties, together with the possible existence of scope economies.R&D, Market Structure, Growth.

Economies of scale and scope in the provision of diagnostic techniques and therapeutic services in Portuguese hospitals

This paper analyses the provision of auxiliary clinical services that are typically carried out within the hospital. We estimate a flexible cost function for the three most important (cost- wise) diagnostic techniques and therapeutic services in Portuguese hospitals: Clinical Pathology, Medical Imaging and Physical Medicine and Rehabilitation. Our objective in carrying out this estimation is the evaluation of economies of scale and scope in the provision of these services. For all services, we find evidence of ray economies of scale and some evidence of economies of scope. These results have important policy implications and can be related to the ongoing discussion of where and how should hospitals provide these services.translog cost function, economies of scale, economies of scope, clinical services, hospitals

Dirac points merging and wandering in a model Chern insulator

We present a model for a Chern insulator on the square lattice with complex first and second neighbor hoppings and a sublattice potential which displays an unexpectedly rich physics. Similarly to the celebrated Haldane model, the proposed Chern insulator has two topologically non-trivial phases with Chern numbers $\pm1$. As a distinctive feature of the present model, phase transitions are associated to Dirac points that can move, merge and split in momentum space, at odds with Haldane's Chern insulator where Dirac points are bound to the corners of the hexagonal Brillouin zone. Additionally, the obtained phase diagram reveals a peculiar phase transition line between two distinct topological phases, in contrast to the Haldane model where such transition is reduced to a point with zero sublattice potential. The model is amenable to be simulated in optical lattices, facilitating the study of phase transitions between two distinct topological phases and the experimental analysis of Dirac points merging and wandering