Bioenergy and agriculture: promises and challenges

Peter Hazell.Biofuels, Agricultural research, Development, Poor Developing countries,

Gaussian density fluctuations, mode coupling theory, and all that

We consider a toy model for glassy dynamics of colloidal suspensions: a single Brownian particle diffusing among immobile obstacles. If Gaussian factorization of static density fluctuations is assumed, this model can be solved without factorization approximation for any dynamic correlation function. The solution differs from that obtained from the ideal mode coupling theory (MCT). The latter is equivalent to including only some, positive definite terms in an expression for the memory function. An approximate re-summation of the complete expression suggests that, under the assumption of Gaussian factorization of static fluctuations, mobile particle's motion is always diffusive. In contrast, MCT predicts that the mobile particle becomes localized at a high enough obstacle density. We discuss the implications of these results for models for glassy dynamics.Comment: to be published in Europhys. Let

Financing medical specialist services in the Netherlands; welfare implications of imperfect agency

From 1995 onward the financing scheme for specialist care in the Netherlands has moved from a fee-for-service scheme to a lump-sum budget scheme. This paper analyses the economic and welfare effects of this policy change. The paper adopts a model that integrates demand and supply considerations and recognizes the potential roles of moral hazard and supplier-induced demand. The model is fully numerical, being estimated and calibrated upon data for the Dutch health care sector. The paper finds that the shift in financing regime has been welfare-reducing. The policy change induced medical specialists to lower the supply of health services which was already too low from a welfare point of view. This conclusion is robust to significant changes in major parameter values.