"Are the Costs of the Business Cycle 'Trivially Small'?"

In his presidential address to the American Economic Association, Robert Lucas claimed that the welfare costs of the business cycle in the United States equaled .05 percent of consumption. His calculation compared the utility of a representative consumer receiving actual per-capita consumption each year with that of a similar consumer receiving the expectation of consumption. To a risk-averse person, the latter path of consumption confers more utility, because it is less volatile. Applying Amartya Sen's chooser-dependent preferences to a nonÐexpected utility case, I will counter Lucas's claim by arguing that people have different attitudes toward risk that is imposed and risk that is voluntarily taken on, and that policymakers, in carrying out public duties, must use sorts of reasoning different from those used by the optimizing consumers of neoclassical economic theory.

Methane and carbon dioxide adsorption on edge-functionalized graphene: A comparative DFT study

With a view towards optimizing gas storage and separation in crystalline and disordered nanoporous carbon-based materials, we use ab initio density functional theory calculations to explore the effect of chemical functionalization on gas binding to exposed edges within model carbon nanostructures. We test the geometry, energetics, and charge distribution of in-plane and out-of-plane binding of CO2 and CH4 to model zigzag graphene nanoribbons edge-functionalized with COOH, OH, NH2, H2PO3, NO2, and CH3. Although different choices for the exchange-correlation functional lead to a spread of values for the binding energy, trends across the functional groups are largely preserved for each choice, as are the final orientations of the adsorbed gas molecules. We find binding of CO2 to exceed that of CH4 by roughly a factor of two. However, the two gases follow very similar trends with changes in the attached functional group, despite different molecular symmetries. Our results indicate that the presence of NH2, H2PO3, NO2, and COOH functional groups can significantly enhance gas binding with respect to a hydrogen-passivated edge, making the edges potentially viable binding sites in materials with high concentrations of edge carbons. To first order, in-plane binding strength correlates with the larger permanent and induced dipole moments on these groups. Implications for tailoring carbon structures for increased gas uptake and improved CO2/CH4 selectivity are discussed.Comment: 12 pages, 7 figure

Computability and analysis: the legacy of Alan Turing

We discuss the legacy of Alan Turing and his impact on computability and analysis.Comment: 49 page