36,677 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 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
Erythrocyte as a link between basic and clinical research
© 2011 – IOS Press and the authorsWe review the major hemorheological experimental studies that show the erythrocyte aggregation as a link between basic and clinical research. The results of the clinical cross-sectional and longitudinal studies presented here will highlight the possible association between erythrocyte aggregation and plasma fibrinogen. Basic studies conducted in vitro are also mentioned as for its relevance in answering questions raised in clinical settings, as well as and in understanding the underlying influent factors in the erythrocyte tendency to aggregate and disaggregate.This work was supported by
“Fundação para a Ciência e Tecnologia
Some Implications of the Cosmological Constant to Fundamental Physics
In the presence of a cosmological constant, ordinary Poincare' special
relativity is no longer valid and must be replaced by a de Sitter special
relativity, in which Minkowski space is replaced by a de Sitter spacetime. In
consequence, the ordinary notions of energy and momentum change, and will
satisfy a different kinematic relation. Such a theory is a different kind of a
doubly special relativity. Since the only difference between the Poincare' and
the de Sitter groups is the replacement of translations by certain linear
combinations of translations and proper conformal transformations, the net
result of this change is ultimately the breakdown of ordinary translational
invariance. From the experimental point of view, therefore, a de Sitter special
relativity might be probed by looking for possible violations of translational
invariance. If we assume the existence of a connection between the energy scale
of an experiment and the local value of the cosmological constant, there would
be changes in the kinematics of massive particles which could hopefully be
detected in high-energy experiments. Furthermore, due to the presence of a
horizon, the usual causal structure of spacetime would be significantly
modified at the Planck scale.Comment: 15 pages, lecture presented at the "XIIth Brazilian School of
Cosmology and Gravitation", Mangaratiba, Rio de Janeiro, September 10-23,
200
Cosmological Term and Fundamental Physics
A nonvanishing cosmological term in Einstein's equations implies a
nonvanishing spacetime curvature even in absence of any kind of matter. It
would, in consequence, affect many of the underlying kinematic tenets of
physical theory. The usual commutative spacetime translations of the Poincare'
group would be replaced by the mixed conformal translations of the de Sitter
group, leading to obvious alterations in elementary concepts such as time,
energy and momentum. Although negligible at small scales, such modifications
may come to have important consequences both in the large and for the
inflationary picture of the early Universe. A qualitative discussion is
presented which suggests deep changes in Hamiltonian, Quantum and Statistical
Mechanics. In the primeval universe as described by the standard cosmological
model, in particular, the equations of state of the matter sources could be
quite different from those usually introduced.Comment: RevTeX, 4 pages. Selected for Honorable Mention in the Annual Essay
Competition of the Gravity Research Foundation for the year 200
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