Mu-tau neutrino refraction and collective three-flavor transformations in supernovae

We study three-flavor collective neutrino transformations in the dense-neutrino region above the neutrino sphere of a supernova core. We find that two-flavor conversions driven by the atmospheric mass difference and the 13-mixing angle capture the full effect if one neglects the second-order difference between the muon and tau neutrino refractive index. Including this "mu-tau matter term" provides a resonance at a density of approximately 3 x 10^7 g cm^-3 that typically causes significant modifications of the overall electron neutrino and antineutrino survival probabilities. This effect is surprisingly sensitive to deviations from maximal 23-mixing, being different for each octant.Comment: 9 pages, 7 figures. New presentation of results, version to be published in PR

"Monetary Shocks in a Model with Loss of Skills"

Unemployment shows persistent and long lasting responses to nominal and real shocks. Standard real business cycle models with search frictions but homogeneous labor force are able to generate some persistence, but not enough to match the empirical evidence. Moreover, empirical studies emphasize the importance of the heterogeneity of the unemployment pool to fully understand unemployment dynamics. In particular, in most European countries the incidence of long term unemployment is big and well known. One of the causes/consequences of long-term unemployment is the skill deterioration of the unemployment pool. In this paper we introduce the loss of skill mechanism, and therefore an heterogeneous labor force, in a New Keynesian framework with search frictions. Calibrating the model to the Spanish economy, we show that the loss of skill mechanism helps to explain the persistence in the response of unemployment to monetary shocks.

"Cyclical Informality and Unemployment"

The proportion of informal or unprotected workers in developing countries is large. In developing economies, the fraction of informal workers can be as high as 70% of total employment. For economies with significant informal sectors, business cycle fluctuations and labor market policy interventions can have important effects on the unemployment rate, and also produce large reallocations of workers between "regulated" and "unregulated" jobs. In this paper, we report the main cyclical patterns of one such labor market: Brazil. We then use the empirical regularities found in the data to build, calibrate, and simulate a two-sector search and matching labor market model, in which firms have the choice of hiring workers formally or informally. We find that our model, built in the spirit of traditional search and matching models, can explain well most of the cyclical properties found in the data. We also show that government policies that decrease the cost of formal jobs, or increase the cost of informality, raise the share of formal employment while reducing unemployment.

Monetary Shocks in a Model with Loss of Skills (Revised in February 2009)

This paper studies the effects of a monetary shock on real and nominal variables, such as output, inflation and especially unemployment, within a framework which combines a New Keynesian business cycle model model with microfounded labor market in the style of the search and matching literature. We assume that unemployed workers can lose their skill over time and show that this mechanism helps explain the slugish response of unemployment to monetary shocks observed in the data, while also replicating the behavior of output, inflation and employment.

"The Effects of the Loss of Skills on Unemployment Fluctuations"

This paper studies the effects of the loss of skills on the persistence of unemployment and other macroeconomic variables. It combines a Real Business Cycle model with a search and matching labor market to explain how the loss of skill of workers and the subsequent decrease in their probability of finding new jobs creates more persistent business cycles. The paper proves that the introduction of this mechanism improves the performance of the model and is able to replicate cross country differences in unemployment and output persistence.

"The Role of the Government in Facilitating TFP Growth during Japan's Rapid Growth Era"

Japan experienced high growth of TFP following World War II. This paper studies the sources of this technological growth and documents the role played by different government policies in achieving such growth. We find that in nonagricultural sectors, TFP growth occurred at first through the import of foreign technologies via licensing, and subsequently through the innovation of its own technologies. In agriculture, TFP grew mostly through the development of its own technologies. The Japanese government played a part in the growth of TFP by directing the adoption of foreign technologies, promoting coordination of R&D activities, and setting up channels for the domestic diffusion of available technologies.

"A Comparison of the Japanese and U.S. Business Cycles"

The paper constructs a consistent set of quarterly Japanese data for the 1960-2002 sample period and compares properties of the Japanese and U.S. business cycles. We document some important differences in the adjustment of labor input between the two countries. In Japan most most of the adjustment is in hours per worker of males and females and also in employment of female. In the U.S. most of the adjustment is in employment of both males and females. We formulate, estimate and analyze a model that makes distinction between the intensive and extensive margin and allows for gender differences in labor supply. A weak empirical correlation between hours per worker and employment in Japanese data is a puzzle for our theory.

Life-Cycle Search, Match Quality and Japan's Labor Flow

The Japanese labor market displays U-shaped unemployment and separation rates, and declining job-finding rates as workers age. Traditional infinite horizon search models of the labor market cannot account for such patterns. We develop a life-cycle search and matching model that features random match quality and incorporates elements capturing several main characteristics of the Japanese labor market. We show that the model, calibrated for Japan, replicates the life-cycle properties of the data. Our model, following an empirically plausible productivity drop, produces changes in the steady state levels of the unemployment and finding rates similar in magnitude to those observed in Japan since the 1980s.

On the Role of Policy Interventions in Structural Change and Economic Development: The Case of Postwar Japan

In this paper, we study the structural change occurring in Japan's post-World War II era of rapid economic growth. We use a two-sector neoclassical growth model with government policies to analyze the evolution of the Japanese economy in this period and to assess the role of such policies. Our model is able to replicate the empirical behavior of the main macroeconomic variables. Three findings emerge from our policy analysis. First, neither price and investment subsidies to the agricultural sector, nor industrial policy play a crucial role in the rapid postwar growth. Second, while a government subsidy for families in urban areas could have facilitated migration from the agricultural to the non-agricultural sector, such a policy would not have improved the overall performance of the Japanese economy. Finally, had there existed a labor migration barrier, the negative long-run level effect on output would have been substantial.