1,047 research outputs found
Spillover Effects of Mass Layoffs
Using administrative data on firms and workers in Germany, we quantify the spillover effects of mass layoffs. Our empirical strategy combines matching with an event study approach to trace employment and wages in regions hit by a mass layoff relative to suitable control regions. We find sizable and persistent negative spillover effects on the regional economy: regions, and especially firms producing in the same broad industry as the layoff plant, lose many more jobs than in the initial layoff. In contrast, negative employment effects on workers employed in the region at the time of the mass layoff are considerably smaller. Strikingly, workers younger than 50 suffer no employment losses, as geographic mobility fully shields them from the decline in local employment opportunities
Rapid enzymatic test for phenotypic HIV protease drug resistance
A phenotypic resistance test based on recombinant expression of the active HIV protease in E. coli from patient blood samples was developed. The protease is purified in a rapid onestep procedure as active enzyme and tested for inhibition by five selected synthetic inhibitors (amprenavir, indinavir, nelfinavir, ritonavir, and saquinavir) used presently for chemotherapy of HIVinfected patients. The HPLC system used in a previous approach was replaced by a continuous fluorogenic assay suitable for highthroughput screening on microtiter plates. This reduces significantly the total assay time and allows the determination of inhibition constants (K-i). The Michaelis constant (K-m) and the inhibition constant (K-i) of recombinant wildtype protease agree well with published data for cloned HIV protease. The enzymatic test was evaluated with recombinant HIV protease derived from eight HIVpositive patients scored from sensitive to highly resistant according to mutations detected by genotypic analysis. The measured K-i values correlate well with the genotypic resistance scores, but allow a higher degree of differentiation. The noninfectious assay enables a more rapid yet sensitive detection of HIV protease resistance than other phenotypic assays
Quantum Decoherence of Two Qubits
It is commonly stated that decoherence in open quantum systems is due to
growing entanglement with an environment. In practice, however, surprisingly
often decoherence may equally well be described by random unitary dynamics
without invoking a quantum environment at all. For a single qubit, for
instance, pure decoherence (or phase damping) is always of random unitary type.
Here, we construct a simple example of true quantum decoherence of two qubits:
we present a feasible phase damping channel of which we show that it cannot be
understood in terms of random unitary dynamics. We give a very intuitive
geometrical measure for the positive distance of our channel to the convex set
of random unitary channels and find remarkable agreement with the so-called
Birkhoff defect based on the norm of complete boundedness.Comment: 5 pages, 4 figure
Institute of Ion Beam Physics and Materials Research: Annual Report 2001
Summary of the scientific activities of the institute in 2001 including selected highlight reports, short research contributions and an extended statistics overview
Economic Case Study of Process Modification for the Allyl Chloride Process
Society's increasing environmental awareness has forced the government to pass more stringent environmental laws. These laws have put both economic and societal pressure on companies to cleanup chemical processes. Such current and anticipated future regulations regarding environmental pollution have created the need to significantly change the manufacturing philosophy in this country. The major impact of these regulations is the requirement that companies must re-analyze their current schemes for chemical waste reduction and develop new strategies for minimizing the production of waste and hazardous chemicals
System-environment correlations and Non-Markovian dynamics
We determine the total state dynamics of a dephasing open quantum system
using the standard environment of harmonic oscillators. Of particular interest
are random unitary approaches to the same reduced dynamics and
system-environment correlations in the full model. Concentrating on a model
with an at times negative dephasing rate, the issue of "non-Markovianity" will
also be addressed. Crucially, given the quantum environment, the appearance of
non-Markovian dynamics turns out to be accompanied by a loss of
system-environment correlations. Depending on the initial purity of the qubit
state, these system-environment correlations may be purely classical over the
whole relevant time scale, or there may be intervals of genuine
system-environment entanglement. In the latter case, we see no obvious relation
between the build-up or decay of these quantum correlations and
"Non-Markovianity"
Optical Properties of Layered Superconductors near the Josephson Plasma Resonance
We study the optical properties of crystals with spatial dispersion and show
that the usual Fresnel approach becomes invalid near frequencies where the
group velocity of the wave packets inside the crystal vanishes. Near these
special frequencies the reflectivity depends on the atomic structure of the
crystal provided that disorder and dissipation are very low. This is
demonstrated explicitly by a detailed study of layered superconductors with
identical or two different alternating junctions in the frequency range near
the Josephson plasma resonance. Accounting for both inductive and charge
coupling of the intrinsic junctions, we show that multiple modes are excited
inside the crystal by the incident light, determine their relative amplitude by
the microscopic calculation of the additional boundary conditions and finally
obtain the reflectivity.
Spatial dispersion also provides a novel method to stop light pulses, which
has possible applications for quantum information processing and the artificial
creation of event horizons in a solid.Comment: 25 pages, 20 figures, submitted to Phys. Rev.
Physics investigations of a compact simulation of a large fast breeder reactor. SNEAK-Assembly 10
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