4,559 research outputs found
ooRexx 5 Yielding Swiss Army Knife Usability
The new version 5.0 of the message based object-oriented programming language ooRexx ("open object-oriented REXX") is easy to learn, yet powerful. This article introduces some of the new language features with nutshell examples that at the same time demonstrate its power when deployed in different operating system environments. The modern native API of ooRexx makes it in addition very easy to extend the language with new functionality and deploy it as a macro language for any C++-based application
Correlated Exciton Transport in Rydberg-Dressed-Atom Spin Chains
We investigate the transport of excitations through a chain of atoms with
non-local dissipation introduced through coupling to additional short-lived
states. The system is described by an effective spin-1/2 model where the ratio
of the exchange interaction strength to the reservoir coupling strength
determines the type of transport, including coherent exciton motion, incoherent
hopping and a regime in which an emergent length scale leads to a preferred
hopping distance far beyond nearest neighbors. For multiple impurities, the
dissipation gives rise to strong nearest-neighbor correlations and
entanglement. These results highlight the importance of non-trivial
dissipation, correlations and many-body effects in recent experiments on the
dipole-mediated transport of Rydberg excitations.Comment: 5 page
Entrepreneur of ones own labour force - some conclusions for the sociology of education
"Annahme ist, daß sich aktuell ein Wandel der basalen Verfassung von Arbeitskraft vollzieht. Nach einigen Anmerkungen zur \u27Entgrenzung\u27 von Arbeit als Hintergrund für die postulierte Entwicklung (1), werden drei Thesen zur näheren Charakterisierung des \u27Arbeitskraftunternehmers\u27 und eine historische Einordnung entwickelt (2). Es folgen Überlegungen zu den vermutlich entscheidenden Kompetenzen des neuen Arbeitskrafttypus (3), zur sich damit verändernden Bedeutung von \u27Beruf\u27 (4) und zum möglichen Wandel von Ausbildung und Bildung (5)." (Autorenreferat).The article Starts from the assumption, that the basic Constitution of labour force is changing. Some remarks are made on the „fading of boundaries" within work in order to explain this development (1). Then, three theses which characterise the concept "entrepreneur of his own labour force" are presented and considered in a historical perspective (2). Some reflections are given on the presumed core-competences of the new form of labour force (3), on the change of the meaning of vocation (4), and on possible changes in the field of education and vocational training (5). (DIPF/Orig.
Self-induced decoherence in dense neutrino gases
Dense neutrino gases exhibit collective oscillations where "self-maintained
coherence" is a characteristic feature, i.e., neutrinos of different energies
oscillate with the same frequency. In a non-isotropic gas, however, the flux
term of the neutrino-neutrino interaction has the opposite effect of causing
kinematical decoherence of neutrinos propagating in different directions, an
effect that is at the origin of the "multi-angle behavior" of neutrinos
streaming off a supernova core. We cast the equations of motion in a form where
the role of the flux term is manifest. We study in detail the symmetric case of
equal neutrino and antineutrino densities where the evolution consists of
collective pair conversions ("bipolar oscillations"). A gas of this sort is
unstable in that an infinitesimal anisotropy is enough to trigger a run-away
towards flavor equipartition. The "self-maintained coherence" of a perfectly
isotropic gas gives way to "self-induced decoherence."Comment: Revtex, 16 pages, 12 figure
Incremental Risk Vulnerability
We present a necessary and sufficient condition on an agent’s utility function for a simple mean preserving spread in an independent background risk to increase the agent’s risk aversion (incremental risk vulnerability). Gollier and Pratt (1996) have shown that declining and convex risk aversion as well as standard risk aversion are sufficient for risk vulnerability. We show that these conditions are also sufficient for incremental risk vulnerability. In addition, we present sufficient conditions for a restricted set of stochastic increases in an independent background risk to increase risk aversion.
WDX-Analysis of the New Superconductors RO(1-x)F(x)FeAs and Its Consequences on the Electronic Phase Diagram
Polycrystalline samples of RO1-xFxFeAs (0 < x < 0.25) (R = La, Sm, Gd) were
investigated by wavelength-dispersive X-ray spectroscopy (WDX) in the electron
microscope to determine the composition of the samples, in particular the
fluorine content. It was found that the measured fluorine content can deviate
considerably from the initial weight. In the lanthanum compound LaO1-xFxFeAs,
we found good agreement mainly for x > 0.05, but for x < 0.05 the fluorine
hardly goes into the sample. For the samarium compound we measured less than
half the fluorine in the sample as initially weighed at all fluorine
concentrations. These measured values are taken into account when drawing the
electronic phase diagrams of LaO1-xFxFeAs and SmO1-xFxFeAs. This leads to a
more consistent picture of both of the diagrams in comparison to the plot of
the initial weight.Comment: 5 pages, 4 figures, Accepted for publication in Journal of
Superconductivity and Novel Magnetis
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