The financial crisis of late 2008 shifted household expenditure downward, as financial institutions tightened lending standards and required repayment of outstanding consumer loans. The crisis also raised financial frictions by depleting the equity capital of financial institutions. The result was a severe reduction in business and residential investment expenditure. The zero bound on the inter...

There is ample empirical evidence that phenotypic diversification in an adaptive radiation is the outcome of divergent natural selection related to differential resource use. In contrast, the role of ecological forces in favoring and maintaining reproductive isolation in nature remains poorly understood. If the same forces driving phenotypic divergence are also responsible for speciation, one w...

A formal asymptotic analysis of two classes of phase field models for void growth and coarsening in irradiated solids has been performed to assess their sharp-interface kinetics. It was found that the sharp interface limit of type B models, which include only point defect concentrations as order parameters governed by Cahn-Hilliard equations, captures diffusion-controlled kinetics. It was also ...

We previously studied equilibrium in a particularly simple world – an endowment economy. This was useful for getting intuition about what determined the real interest rate, but lacked realism. In this section we endogenize supply. The concept of equilibrium is identical to before, but the set up is more interesting. Now we have firms that produce output using capital and labor, and households t...