A tractable incomplete-market model with endogenous unemployment risk, sticky prices, real wage rigidity and a fiscal side is calibrated to Euro Area countries and used to analyze the macroeconomic effects of lockdown policies. Modeling them as a shock to the extensive margin of labor adjustment – a rise in separations – produces large and persistent negative effects on output, unemployment and welfare, raises precautionary savings and lowers inflation, in line with early evidence about inflation dynamics. Modeling lockdowns as a shock to the intensive margin – a fall in labor utilization – produces small and short-lived macroeconomic and welfare effects, and implies a counterfactual rise in inflation. Conditional on a lockdown (separation) shock, raising public spending or extending UI benefits by large amounts is much more effective in stimulating the economy than during normal times. Quantitatively however, the ability of such policies to flatten the output and unemployment curves remains limited, even though these policies can alleviate a reasonable share of the aggregate welfare losses from the lockdown.

This work considers the problem of the optimal design of an hydrogen transmission network. This design problem includes the topology determination and the pipelines dimensioning problem. We define a local search method that simultaneously looks for the least cost topology of the network and for the optimal diameter of each pipe. These two problems were generally solved separately these last years. The application to the case of development of future hydrogen pipeline networks in France has been conducted at the local, regional and national levels. We compare the proposed approach with another using Tabu search heuristic.

In the US unemployment insurance (UI) system, only a fraction of those eligible for benefits actually collect them. We estimate this fraction using CPS data and detailed state-level eligibility criteria. It averaged 77% from 1989 − 2012 and is negatively correlated with the unemployment rate. These empirical facts are explained in an equilibrium search model where firms finance UI benefits and are heterogeneous with respect to their specific tax rate, which is experience rated. In equilibrium, low tax firms effectively offer workers an alternative UI scheme featuring a faster job arrival rate and a higher wage offer. Some eligible workers prefer the "market" scheme and thus do not collect UI. The model captures the negative correlation between the take-up and unemployment rate. If all eligible unemployed collect, benefit expenditures increase by 16% and welfare increases. Average search effort decreases, but the unemployment rate and duration decrease as vacancy creation increases.