The return to firm investment in human capital

In this paper we estimate the rate of return to firm investments in human capital in the form of formal job training. We use a panel of large firms with unusually detailed information on the duration of training, the direct costs of training, and several firm characteristics such as their output, workforce characteristics and capital stock. Our estimates of the return to training vary substantially across firms. On average it is -7% for firms not providing training and 24% for those providing training. Formal job training is a good investment for many firms and the economy, possibly yielding higher returns than either investments in physical capital or investments in schooling. In spite of this, observed amounts of formal training are very small

Enforcement of regulation, informal labor and firm performance

This paper investigates how enforcement of labor regulation affects the firm’s use of informal labor and firm performance. Using firm level data on informal employment and firm performance, and administrative data on enforcement of regulation at the city level, we show that in areas where law enforcement is stricter firms employ a smaller amount of informal employment. Furthermore, by reducing the firm’s access to unregulated labor, stricter enforcement is also associated with lower labor productivity. We control for different regional and firm characteristics, and we instrument enforcement with a measure of the access of labor inspectors to firms. Taken together, our findings suggest that increased access to labor flexibility significantly improves firm performance

Stability of the Einstein static universe in presence of vacuum energy

The Einstein static universe has played a central role in a number of emergent scenarios recently put forward to deal with the singular origin of the standard cosmological model. Here we study the existence and stability of the Einstein static solution in presence of vacuum energy corresponding to conformally-invariant fields. We show that the presence of vacuum energy stabilizes this solution by changing it to a centre equilibrium point, which is cyclically stable. This allows non-singular emergent cosmological models to be constructed in which initially the universe oscillates indefinitely about an initial Einstein static solution and is thus past eternal.Comment: Some references adde

Does High Inflation Affect Growth in the Long and Short Run?

This paper investigates the relationship between inflation and output in the context of an economy facing persistent high inflation. By analyzing the case of Brazil, we find that inflation does not impact real output in the long run, but that in the short run there exists a negative effect from inflation on output. These results support Sidrauski’s (1967) superneutrality of money in the long run, but cast doubt on the short run implications of the model for separable utility functions in consumption and real money balances, as exposed by Fischer (1979). The results are more likely to support a class of utility functions in which real money balances and consumption are perfect complements.inflation; growth; output

From de Sitter to de Sitter: A non-singular inflationary universe driven by vacuum

A semi-classical analysis of vacuum energy in the expanding spacetime suggests that the cosmological term decays with time, with a concomitant matter production. For early times we find, in Planck units, $\Lambda \approx H^4$, where H is the Hubble parameter. The corresponding cosmological solution has no initial singularity, existing since an infinite past. During an infinitely long period we have a quasi-de Sitter, inflationary universe, with $H \approx 1$. However, at a given time, the expansion undertakes a phase transition, with H and $\Lambda$ decreasing to nearly zero in a few Planck times, producing a huge amount of radiation. On the other hand, the late-time scenario is similar to the standard model, with the radiation phase followed by a dust era, which tends asymptotically to a de Sitter universe, with vacuum dominating again.Comment: This essay received an "honorable mention" in the 2006 Essay Competition of the Gravity Research Foundatio

Bursts in discontinuous Aeolian saltation

Close to the onset of Aeolian particle transport through saltation we find in wind tunnel experiments a regime of discontinuous flux characterized by bursts of activity. Scaling laws are observed in the time delay between each burst and in the measurements of the wind fluctuations at the fluid threshold Shields number $\theta_c$. The time delay between each burst decreases on average with the increase of the Shields number until sand flux becomes continuous. A numerical model for saltation including the wind-entrainment from the turbulent fluctuations can reproduce these observations and gives insight about their origin. We present here also for the first time measurements showing that with feeding it becomes possible to sustain discontinuous flux even below the fluid threshold