210 research outputs found
Emigration and Wages: The EU Enlargement Experiment
The enlargement of the European Union provides a unique opportunity to study the impact of the lifting of migration restrictions on the migrant sending countries. With EU enlargement in 2004, 1.2 million workers from Eastern Europe emigrated to the UK and Ireland. I use this emigration wave to show that emigration significantly changed the wage distribution in the sending country, in particular between young and old workers. Using a novel dataset from Lithuania, the UK and Ireland for the calibration of a structural model of labor demand, I find that over the period of five years emigration increased the wages of young workers by 6%, while it had no effect on the wages of old workers. Contrary to the immigration literature, there is no significant effect of emigration on the wage distribution between high-skilled and low-skilled workers.emigration, EU enlargement, European integration, wage distribution
Efficient Wiener filtering without preconditioning
We present a new approach to calculate the Wiener filter solution of general
data sets. It is trivial to implement, flexible, numerically absolutely stable,
and guaranteed to converge. Most importantly, it does not require an ingenious
choice of preconditioner to work well. The method is capable of taking into
account inhomogeneous noise distributions and arbitrary mask geometries. It
iteratively builds up the signal reconstruction by means of a messenger field,
introduced to mediate between the different preferred bases in which signal and
noise properties can be specified most conveniently. Using cosmic microwave
background (CMB) radiation data as a showcase, we demonstrate the capabilities
of our scheme by computing Wiener filtered WMAP7 temperature and polarization
maps at full resolution for the first time. We show how the algorithm can be
modified to synthesize fluctuation maps, which, combined with the Wiener filter
solution, result in unbiased constrained signal realizations, consistent with
the observations. The algorithm performs well even on simulated CMB maps with
Planck resolution and dynamic range.Comment: 5 pages, 2 figures. Submitted to Astronomy and Astrophysics. Replaced
to match published versio
ARKCoS: Artifact-Suppressed Accelerated Radial Kernel Convolution on the Sphere
We describe a hybrid Fourier/direct space convolution algorithm for compact
radial (azimuthally symmetric) kernels on the sphere. For high resolution maps
covering a large fraction of the sky, our implementation takes advantage of the
inexpensive massive parallelism afforded by consumer graphics processing units
(GPUs). Applications involve modeling of instrumental beam shapes in terms of
compact kernels, computation of fine-scale wavelet transformations, and optimal
filtering for the detection of point sources. Our algorithm works for any
pixelization where pixels are grouped into isolatitude rings. Even for kernels
that are not bandwidth limited, ringing features are completely absent on an
ECP grid. We demonstrate that they can be highly suppressed on the popular
HEALPix pixelization, for which we develop a freely available implementation of
the algorithm. As an example application, we show that running on a high-end
consumer graphics card our method speeds up beam convolution for simulations of
a characteristic Planck high frequency instrument channel by two orders of
magnitude compared to the commonly used HEALPix implementation on one CPU core
while maintaining at typical a fractional RMS accuracy of about 1 part in 10^5.Comment: 10 pages, 6 figures. Submitted to Astronomy and Astrophysics.
Replaced to match published version. Code can be downloaded at
https://github.com/elsner/arkco
Fast calculation of the Fisher matrix for cosmic microwave background experiments
The Fisher information matrix of the cosmic microwave background (CMB)
radiation power spectrum coefficients is a fundamental quantity that specifies
the information content of a CMB experiment. In the most general case, its
exact calculation scales with the third power of the number of data points N
and is therefore computationally prohibitive for state-of-the-art surveys.
Applicable to a very large class of CMB experiments without special symmetries,
we show how to compute the Fisher matrix in only O(N^2 log N) operations as
long as the inverse noise covariance matrix can be applied to a data vector in
time O(l_max^3 log l_max). This assumption is true to a good approximation for
all CMB data sets taken so far. The method takes into account common
systematics such as arbitrary sky coverage and realistic noise correlations. As
a consequence, optimal quadratic power spectrum estimation also becomes
feasible in O(N^2 log N) operations for this large group of experiments. We
discuss the relevance of our findings to other areas of cosmology where optimal
power spectrum estimation plays a role.Comment: 4 pages, 1 figures. Accepted for publication in Astronomy and
Astrophysics Letters. Replaced to match published versio
Does emigration benefit the stayers? Evidence from EU enlargement
Around 9% of the Lithuanian workforce emigrated to Western Europe after the enlargement of the European Union in 2004. I exploit this emigration wave to study the effect of emigration on wages in the sending country. Using household data from Lithuania and work permit and census data from the UK and Ireland, I demonstrate that emigration had a significant positive effect on the wages of stayers. A one percentage-point increase in the emigration rate predicts a 0.67% increase in real wages. This effect, however, is only statistically significant for men
Does emigration increase the wages of non-emigrants in sending countries?
How migration affects labor markets in receiving countries is well understood, but less is known about how migration affects labor markets in sending countries, particularly the wages of workers who do not emigrate. Most studies find that emigration increases wages in the sending country but only for non-emigrants with substitutable skills similar to those of emigrants; non-emigrants with different (complementary) skills lose. These wage reactions are short-term effects, however. If a country loses many highly educated workers, the economy can become less productive altogether, leading to lower wages for everyone in the long term
Using hybrid GPU/CPU kernel splitting to accelerate spherical convolutions
We present a general method for accelerating by more than an order of
magnitude the convolution of pixelated functions on the sphere with a
radially-symmetric kernel. Our method splits the kernel into a compact
real-space component and a compact spherical harmonic space component. These
components can then be convolved in parallel using an inexpensive commodity GPU
and a CPU. We provide models for the computational cost of both real-space and
Fourier space convolutions and an estimate for the approximation error. Using
these models we can determine the optimum split that minimizes the wall clock
time for the convolution while satisfying the desired error bounds. We apply
this technique to the problem of simulating a cosmic microwave background (CMB)
anisotropy sky map at the resolution typical of the high resolution maps
produced by the Planck mission. For the main Planck CMB science channels we
achieve a speedup of over a factor of ten, assuming an acceptable fractional
rms error of order 1.e-5 in the power spectrum of the output map.Comment: 9 pages, 11 figures, 1 table, accepted by Astronomy & Computing w/
minor revisions. arXiv admin note: substantial text overlap with
arXiv:1211.355
Does Emigration Benefit the Stayers? The EU Enlargement as a Natural Experiment. Evidence from Lithuania
The eastern enlargement of the European Union in 2004 triggered a large flow of migrant workers from the new member states to the UK and Ireland. This paper analyzes the impact of this migration wave on the real wages in the source countries. I consider the case of Lithuania, which had the highest share of emigrants relative to its workforce among all ten new member states. Using data from the Lithuanian Household Budget Survey and the Irish Census, I find that emigration had a significant positive effect on the wages of men who stayed in the country, but no such effect is visible for women. A percentage point increase in the emigration rate increases the real wage of men on average by 1%. Several robustness checks confirm this result.Emigration, Labor Mobility, EU Enlargement
Emigration and Wages: The EU Enlargement Experiment
This paper studies the impact of a large emigration wave on real wages in the source country. Following EU enlargement in 2004, a large share of the workforce of the Central and Eastern Europe emigrated to Western Europe. Using data from Lithuania for the calibration of a factor demand model I show that emigration had a significant short-run impact on real wages in the source country. In particular, emigration led to a change in the wage distribution between young and old workers. The wages of young workers increased by 6%, whereas the wages of old workers decreased by around 1%. On the contrary, I find no effect on the wage distribution between workers of different education levels.Emigration, EU Enlargement, European Integration, Wage Distribution
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