9,285 research outputs found
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 firmâs 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 firmâs 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 Sidrauskiâs (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, ,
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 .
However, at a given time, the expansion undertakes a phase transition, with H
and 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 . 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
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