5,527 research outputs found
Enforcement of Labor Regulation and Informality
Enforcement of labor regulations in the formal sector may drive workers to informality because they increase the costs of formal labor. But better compliance with mandated benefits makes it attractive to be a formal employee. We show that, in locations with frequent inspections workers pay for mandated benefits by receiving lower wages. Wage rigidity prevents downward adjustment at the bottom of the wage distribution. As a result, lower paid formal sector jobs become attractive to some informal workers, inducing them to want to move to the formal sector.labor regulation, informality
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
Friedmann cosmology with decaying vacuum density
Among the several proposals to solve the incompatibility between the observed
small value of the cosmological constant and the huge value obtained by quantum
field theories, we can find the idea of a decaying vacuum energy density,
leading from high values at early times of universe evolution to the small
value observed nowadays. In this paper we consider a variation law for the
vacuum density recently proposed by Schutzhold on the basis of quantum field
estimations in the curved, expanding background, characterized by a vacuum
density proportional to the Hubble parameter. We show that, in the context of
an isotropic and homogeneous, spatially flat model, the corresponding solutions
retain the well established features of the standard cosmology, and, in
addition, are in accordance with the observed cosmological parameters. Our
scenario presents an initial phase dominated by radiation, followed by a dust
era long enough to permit structure formation, and by an epoch dominated by the
cosmological term, which tends asymptotically to a de Sitter universe. Taking
the matter density equals to half of the vacuum energy density, as suggested by
observation, we obtain a universe age given by Ht = 1.1, and a decelerating
parameter equals to -1/2.Comment: Accepted for publication in General Relativity and Gravitatio
Bandlimited approximations to the truncated Gaussian and applications
In this paper we extend the theory of optimal approximations of functions in the -metric by entire functions of prescribed
exponential type (bandlimited functions). We solve this problem for the
truncated and the odd Gaussians using explicit integral representations and
fine properties of truncated theta functions obtained via the maximum principle
for the heat operator. As applications, we recover most of the previously known
examples in the literature and further extend the class of truncated and odd
functions for which this extremal problem can be solved, by integration on the
free parameter and the use of tempered distribution arguments. This is the
counterpart of the work \cite{CLV}, where the case of even functions is
treated.Comment: to appear in Const. Appro
The return to the 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
Inequality and employment in a dual economy: enforcement of labor regulation in Brazil
This paper studies the impact of an increase in the enforcement of labor regulations on unemployment and inequality, using city level data from Brazil. We find that stricter enforcement (affecting the payment of mandated benefits to formal workers) leads to: higher unemployment, less income inequality, a higher proportion of formal employment, and a lower formal wage premium. Our results are consistent with a model where stricter enforcement causes a contraction in labor demand in the formal sector; and where workers value mandated benefits highly, so that there is an increase in the formal sector labor supply, an increase in the willingness to become unemployed to search for a formal sector job, and a decrease in labor supply to the informal sector
Obtaining pressure versus concentration phase diagrams in spin systems from Monte Carlo simulations
We propose an efficient procedure for determining phase diagrams of systems
that are described by spin models. It consists of combining cluster algorithms
with the method proposed by Sauerwein and de Oliveira where the grand canonical
potential is obtained directly from the Monte Carlo simulation, without the
necessity of performing numerical integrations. The cluster algorithm presented
in this paper eliminates metastability in first order phase transitions
allowing us to locate precisely the first-order transitions lines. We also
produce a different technique for calculating the thermodynamic limit of
quantities such as the magnetization whose infinite volume limit is not
straightforward in first order phase transitions. As an application, we study
the Andelman model for Langmuir monolayers made of chiral molecules that is
equivalent to the Blume-Emery-Griffiths spin-1 model. We have obtained the
phase diagrams in the case where the intermolecular forces favor interactions
between enantiomers of the same type (homochiral interactions). In particular,
we have determined diagrams in the surface pressure versus concentration plane
which are more relevant from the experimental point of view and less usual in
numerical studies
Globalization and inequality in Latin America
We survey the recent literature studying the effects of globalization on inequality in Latin America. Our focus is on research emerging from the late 2000s onward, with an emphasis on empirical work considering new mechanisms, studying new dimensions of inequality, and developing new methodologies to capture the many facets of globalization’s relationship to inequality. After summarizing both design-based and quantitative work in this area, we propose directions for future work. Our overarching recommendation is that researchers develop unifying frameworks to help synthesize the results of individual studies that focus on distinct aspects of globalization’s relationship to inequality
Trade Reform and Regional Dynamics: Evidence From 25 Years of Brazilian Matched Employer-Employee Data
We empirically study the dynamics of labor market adjustment following the Brazilian trade reform of the 1990s. We use variation in industry-specific tariff cuts interacted with initial regional industry mix to measure trade-induced local labor demand shocks, and then examine regional and individual labor market responses to those one-time shocks over two decades. Contrary to conventional wisdom, we do not find that the impact of local shocks is dissipated over time through wage-equalizing migration. Instead, we find steadily growing effects of local shocks on regional formal sector wages and employment for 20 years. This finding can be rationalized in a simple equilibrium model with two complementary factors of production, labor and industry-specific factors such as capital, that adjust slowly and imperfectly to shocks. Next, we document rich margins of adjustment induced by the trade reform at the regional and individual level. Workers initially employed in harder hit regions face continuously deteriorating formal labor market outcomes relative to workers employed in less affected regions, and this gap persists even 20 years after the beginning of trade liberalization. Negative local trade shocks induce workers to shift out of the formal tradable sector and into the formal nontradable sector. Non-employment strongly increases in harder-hit regions in the medium run, but in the longer run, non-employed workers eventually find re-employment in the informal sector. Working age population does not react to these local shocks, but formal sector net migration does, consistent with the relative decline of the formal sector and growth of the informal sector in adversely affected regions
A Godel-Friedman cosmology?
Based on the mathematical similarity between the Friedman open metric and
Godel's metric in the case of nearby distances, we investigate a new scenario
for the Universe's evolution, where the present Friedman universe originates
from a primordial Godel universe by a phase transition during which the
cosmological constant vanishes. Using Hubble's constant and the present matter
density as input, we show that the radius and density of the primordial Godel
universe are close, in order of magnitude, to the present values, and that the
time of expansion coincides with the age of the Universe in the standard
Friedman model. In addition, the conservation of angular momentum provides, in
this context, a possible origin for the rotation of galaxies, leading to a
relation between the masses and spins corroborated by observational data.Comment: Extended version, accepted for publication in Physical Review
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