42,012 research outputs found
Financial work incentives in Britain: comparisons over time and between family types
This paper reviews various techniques for quantifying financial incentives to work, shows how financial work incentives have changed across the population since 1979, and estimates how much of these changes are due to changes in the tax and benefit system
Normal mere exposure effect with impaired recognition in Alzheimer’s disease.
We investigated the mere exposure effect and the explicit memory in Alzheimer’s disease (AD) patients and elderly control subjects, using unfamiliar faces. During the exposure phase, the subjects estimated the age of briefly flashed faces. The mere exposure effect was examined by presenting pairs of faces (old and new) and asking participants to select the face they liked. The participants were then presented with a forced-choice explicit recognition task. Controls subjects exhibited above-chance preference and recognition scores for old faces. The AD patients also showed the mere exposure effect but no explicit recognition. These results suggest that the processes involved in the mere exposure effect are preserved in AD patients despite their impaired explicit recognition. The results are discussed in terms of Seamon et al.’s proposal (1995) that processes involved in the mere exposure effect are equivalent to those subserving perceptual priming. These processes would depend on extrastriate areas which are relatively preserved in AD patients
Off-Mass-Shell N Scattering and
We adapt the off-shell N amplitude of the Tucson-Melbourne three-body
force to the half-off-shell amplitude of the pion rescattering contribution to
near threshold. This {\em pion} rescattering contribution,
together with the impulse term, provides a good description of the data when
the half-off-shell amplitude is linked to the phenomenological invariant
amplitudes obtained from meson factory N scattering data.Comment: 3 pages, contributed to STORRI99, Bloomington, Indiana, September
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Calculation of the Mass Spectrum of QED-2 in Light-Front Coordinates
With the aim of a further investigation of the nonperturbative Hamiltonian
approach in gauge field theories, the mass spectrum of QED-2 is calculated
numerically by using the corrected Hamiltonian that was constructed previously
for this theory on the light front. The calculations are performed for a wide
range of the ratio of the fermion mass to the fermion charge at all values of
the parameter \hat\theta related to the vacuum angle \theta. The results
obtained in this way are compared with the results of known numerical
calculations on a lattice in Lorentz coordinates. A method is proposed for
extrapolating the values obtained within the infrared-regularized theory to the
limit where the regularization is removed. The resulting spectrum agrees well
with the known results in the case of \theta=0; in the case of \theta=\pi,
there is agreement at small values of the fermion mass (below the
phase-transition point).Comment: LaTex 2.09, 20 pages, 7 figures. New improved expression for the
effective LF Hamiltonian was adde
Bio-linguistic transition and Baldwin effect in an evolutionary naming-game model
We examine an evolutionary naming-game model where communicating agents are
equipped with an evolutionarily selected learning ability. Such a coupling of
biological and linguistic ingredients results in an abrupt transition: upon a
small change of a model control parameter a poorly communicating group of
linguistically unskilled agents transforms into almost perfectly communicating
group with large learning abilities. When learning ability is kept fixed, the
transition appears to be continuous. Genetic imprinting of the learning
abilities proceeds via Baldwin effect: initially unskilled communicating agents
learn a language and that creates a niche in which there is an evolutionary
pressure for the increase of learning ability.Our model suggests that when
linguistic (or cultural) processes became intensive enough, a transition took
place where both linguistic performance and biological endowment of our species
experienced an abrupt change that perhaps triggered the rapid expansion of
human civilization.Comment: 7 pages, minor changes, accepted in Int.J.Mod.Phys.C, proceedings of
Max Born Symp. Wroclaw (Poland), Sept. 2007. Java applet is available at
http://spin.amu.edu.pl/~lipowski/biolin.html or
http://www.amu.edu.pl/~lipowski/biolin.htm
Non-linear exciton spin-splitting in single InAs/GaAs self-assembled quantum structures in ultrahigh magnetic fields
We report on the magnetic field dispersion of the exciton spin-splitting and
diamagnetic shift in single InAs/GaAs quantum dots (QDs) and dot molecules
(QDMs) up to = 28 T. Only for systems with strong geometric confinement,
the dispersions can be well described by simple field dependencies, while for
dots with weaker confinement considerable deviations are observed: most
importantly, in the high field limit the spin-splitting shows a non-linear
dependence on , clearly indicating light hole admixtures to the valence band
ground state
A Possible Bifurcation in Atmospheres of Strongly Irradiated Stars and Planets
We show that under certain circumstances the differences between the
absorption mean and Planck mean opacities can lead to multiple solutions for an
LTE atmospheric structure. Since the absorption and Planck mean opacities are
not expected to differ significantly in the usual case of radiative
equilibrium, non-irradiated atmospheres, the most interesting situations where
the effect may play a role are strongly irradiated stars and planets, and also
possibly structures where there is a significant deposition of mechanical
energy, such as stellar chromospheres and accretion disks. We have presented an
illustrative example of a strongly irradiated giant planet where the
bifurcation effect is predicted to occur for a certain range of distances from
the star.Comment: 22 pages, 6 figures, submitted to Ap
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