24,575 research outputs found
Employment, wage structure, and the economic cycle: differences between immigrants and natives in Germany and the UK
Differences in the cyclical pattern of employment and wages of immigrants relative
to natives have largely gone unnoticed in the migration literature. In this paper we
show that immigrants and natives react differently to the economic cycle. Based on
over two decades of micro data, our investigation is for two of the largest immigrant
receiving countries in Europe which at the same time are characterised by different
immigrant populations as well as different economic cycles, Germany and the UK.
Understanding the magnitude, nature and possible causes of differences in
responses is relevant for assessing the economic performance of immigrant
communities over time. We show that there are substantial differences in cyclical
responses between immigrants and natives. Our analysis illustrates the magnitude of
these differences, while distinguishing between different groups of immigrants.
Differences in responses may be due to differences in the skill distribution between
immigrant groups and natives, or differences in demand for immigrants and natives
of the same skills due to differential allocation of immigrants and natives across
industries and regions. We demonstrate that substantial differences in cyclical
patterns remain, even within narrowly defined groups. Finally, we estimate a more
structural factor type model that, using regional variation in economic conditions,
separates responses to economic shocks from a secular trend and allows us to
obtain a summary measure for these differences within education groups
Experimental determination of a nonclassical Glauber-Sudarshan P function
A quantum state is nonclassical if its Glauber-Sudarshan P function fails to
be interpreted as a probability density. This quantity is often highly
singular, so that its reconstruction is a demanding task. Here we present the
experimental determination of a well-behaved P function showing negativities
for a single-photon-added thermal state. This is a direct visualization of the
original definition of nonclassicality. The method can be useful under
conditions for which many other signatures of nonclassicality would not
persist.Comment: 4 pages, 4 figure
Nonclassicality filters and quasiprobabilities
Necessary and sufficient conditions for the nonclassicality of bosonic
quantum states are formulated by introducing nonclassicality filters and
nonclassicality quasiprobability distributions. Regular quasiprobabilities are
constructed from characteristic functions which can be directly sampled by
balanced homodyne detection. Their negativities uncover the nonclassical
effects of general quantum states. The method is illustrated by visualizing the
nonclassical nature of a squeezed state.Comment: Significantly revised version, more emphasis on practical applicatio
Space shuttle navigation analysis. Volume 1: GPS aided navigation
Analytical studies related to space shuttle navigation are presented. Studies related to the addition of NAVSTAR Global Positioning System user equipment to the shuttle avionics suite are presented. The GPS studies center about navigation accuracy covariance analyses for both developmental and operational phases of GPS, as well as for various orbiter mission phases
Nonclassical Moments and their Measurement
Practically applicable criteria for the nonclassicality of quantum states are
formulated in terms of different types of moments. For this purpose the moments
of the creation and annihilation operators, of two quadratures, and of a
quadrature and the photon number operator turn out to be useful. It is shown
that all the required moments can be determined by homodyne correlation
measurements. An example of a nonclassical effect that is easily characterized
by our methods is amplitude-squared squeezing.Comment: 12 pages, 6 figure
Measurement of neutrino oscillation with KamLAND: Evidence of spectral distortion
We present results of a study of neutrino oscillation based on a 766 ton/year exposure of KamLAND to reactor antineutrinos. We observe 258 v_e candidate events with energies above 3.4 MeV compared to 365.2±23.7 events expected in the absence of neutrino oscillation. Accounting for 17.8±7.3 expected background events, the statistical significance for reactor v_e over bar (e) disappearance is 99.998%. The observed energy spectrum disagrees with the expected spectral shape in the absence of neutrino oscillation at 99.6% significance and prefers the distortion expected from v_e oscillation effects. A two-neutrino oscillation analysis of the KamLAND data gives Îm^2=7.9_(-0.5)^(+0.6)x10^(-5) eV^2. A global analysis of data from KamLAND and solar-neutrino experiments yields
Îm^2=7.9_(-0.5)^(+0.6)x10^(-5) eV^2 and tan^2Ξ=0.40_(-0.07)^(+0.10), the most precise determination to date
Quantum Correlations from the Conditional Statistics of Incomplete Data
We study, in theory and experiment, the quantum properties of correlated
light fields measured with click-counting detectors providing incomplete
information on the photon statistics. We establish a correlation parameter for
the conditional statistics, and we derive the corresponding nonclassicality
criteria for detecting conditional quantum correlations. Classical bounds for
Pearson's correlation parameter are formulated that allow us, once they are
violated, to determine nonclassical correlations via the joint statistics. On
the one hand, we demonstrate nonclassical correlations in terms of the joint
click statistics of light produced by a parametric down conversion source. On
the other hand, we verify quantum correlations of a heralded, split
single-photon state via the conditional click statistics together with a
generalization to higher-order moments. We discuss the performance of the
presented nonclassicality criteria to successfully discern joint and
conditional quantum correlations. Remarkably, our results are obtained without
making any assumptions on the response function, quantum efficiency, and
dark-count rate of the photodetectors
Neutrino fluence after r-process freeze-out and abundances of Te isotopes in presolar diamonds
Using the data of Richter et al. (1998) on Te isotopes in diamond grains from
a meteorite, we derive bounds on the neutrino fluence and the decay timescale
of the neutrino flux relevant for the supernova r-process. Our new bound on the
neutrino fluence F after freeze-out of the r-process peak at mass number A =
130 is more stringent than the previous bound F < 0.045 (in units of 10**37
erg/cm**2) of Qian et al. (1997) and Haxton et al. (1997) if the neutrino flux
decays on a timescale tau > 0.65 s. In particular, it requires that a fluence
of F = 0.031 be provided by a neutrino flux with tau < 0.84 s. Such a fluence
may be responsible for the production of the solar r-process abundances at A =
124-126 (Qian et al. 1997; Haxton et al. 1997). Our results are based on the
assumption that only the stable nuclei implanted into the diamonds are retained
while the radioactive ones are lost from the diamonds upon decay after
implantation (Ott 1996). We consider that the nanodiamonds are condensed in an
environment with C/O > 1 in the expanding supernova debris or from the exterior
H envelope. The implantation of nuclei would have occurred 10**4-10**6 s after
r-process freeze-out. This time interval may be marginally sufficient to permit
adequate cooling upon expansion for the formation of diamond grains. The
mechanisms of preferential retention/loss of the implanted nuclei are not well
understood.Comment: AASTeX, 11 pages, 3 Postscript figure
ADL: a graphical design language for real time parallel applications
Designing parallel applications is generally experienced as a tedious and difficult task, especially when hard real-time performance requirements have to be met. This paper
discusses on-going work concerning the construction of a Design Entry System which
supports the design phase of parallel real-time industrial application development. In
particular, in this paper we pay attention to the development and implementation of a
graphical Application Design Language. The work is part of the ESPRIT project Hamlet which
focuses on industrial application of transputer-based systems for commercially strategic
real-time applications
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