8,835 research outputs found
Studies of proteinograms in dermatophytes by disc electrophoresis. 1. Protein bands in relation to growth phase
Homogenates were prepared from various growth phases of Microsporum gypseum grown on different amino acids as the nitrogen source. When analyzed on 7.5% polyacrylamide disc gels, the water-soluble proteins in these homogenates gave essentially identical banding patterns
Studies on proteinograms in dermatorphytes by disc electrophoresis. Part 2: Protein bands of keratinophilic fungi
Disc electrophoresis studies on keratinophili fungi demonstrated corresponding proteinograms in morphologically homogeneous strains of the same species, but different in different species of one and the same genus
On Killing vectors in initial value problems for asymptotically flat space-times
The existence of symmetries in asymptotically flat space-times are studied
from the point of view of initial value problems. General necessary and
sufficient (implicit) conditions are given for the existence of Killing vector
fields in the asymptotic characteristic and in the hyperboloidal initial value
problem (both of them are formulated on the conformally compactified space-time
manifold)
Analysis of stochastic time series in the presence of strong measurement noise
A new approach for the analysis of Langevin-type stochastic processes in the
presence of strong measurement noise is presented. For the case of Gaussian
distributed, exponentially correlated, measurement noise it is possible to
extract the strength and the correlation time of the noise as well as
polynomial approximations of the drift and diffusion functions from the
underlying Langevin equation.Comment: 12 pages, 10 figures; corrected typos and reference
Numerical treatment of the hyperboloidal initial value problem for the vacuum Einstein equations. I. The conformal field equations
This is the first in a series of articles on the numerical solution of
Friedrich's conformal field equations for Einstein's theory of gravity. We will
discuss in this paper why one should be interested in applying the conformal
method to physical problems and why there is good hope that this might even be
a good idea from the numerical point of view. We describe in detail the
derivation of the conformal field equations in the spinor formalism which we
use for the implementation of the equations, and present all the equations as a
reference for future work. Finally, we discuss the implications of the
assumptions of a continuous symmetry.Comment: 19 pages, LaTeX2
Solid particle erosion and viscoelastic properties of thermoplastic polyurethanes
The wear resistance of several thermoplastic polyurethanes (TPUs) having different chemical nature and micronscale
arrangement of the hard and soft segments has been investigated by means of erosion and abrasion tests. The goal was
correlating the erosion performances of the materials to their macroscopic mechanical properties. Unlike conventional tests,
such as hardness and tensile measurements, viscoelastic analysis proved to be a valuable tool to study the erosion resistance
of TPUs. In particular, a strict correlation was found between the erosion rate and the high-frequency (~10^7 Hz) loss modulus.
The latter reflects the actual ability of TPU to dissipate the impact energy of the erodent particles
The composition of meteoroids impacting LDEF
So far we have completed an initial scanning electron microscopy (SEM) survey of craters on the exterior of the Long Duration Exposure Facility (LDEF) in the 100 micron to 1mm size range and done some quantitative analysis. In typical craters, the residue appears to be a mixture of glass and FeNi and sulfide beads with an overall chondritic elemental composition. In less than 10 percent of the craters, there is a substantial amount of meteoroid debris that also contains unmelted mineral grains. The relatively high abundance of forsterite and enststite among these irregular grains suggests that a high melting point probably plays a role in surviving impact without melting
Influence of molecular temperature on the coherence of fullerenes in a near-field interferometer
We study C70 fullerene matter waves in a Talbot-Lau interferometer as a
function of their temperature. While the ideal fringe visibility is observed at
moderate molecular temperatures, we find a gradual degradation of the
interference contrast if the molecules are heated before entering the
interferometer. A method is developed to assess the distribution of the
micro-canonical temperatures of the molecules in free flight. This way the
heating-dependent reduction of interference contrast can be compared with the
predictions of quantum theory. We find that the observed loss of coherence
agrees quantitatively with the expected decoherence rate due to the thermal
radiation emitted by the hot molecules.Comment: 11 pages, 9 figure
Many-body effects on the Rashba-type spin splitting in bulk bismuth tellurohalides
We report on many-body corrections to one-electron energy spectra of bulk
bismuth tellurohalides---materials that exhibit a giant Rashba-type spin
splitting of the band-gap edge states. We show that the corrections obtained in
the one-shot approximation noticeably modify the spin-orbit-induced spin
splitting evaluated within density functional theory. We demonstrate that
taking into account many-body effects is crucial to interpret the available
experimental data.Comment: 6 pages, 1 figur
3D simulations of Einstein's equations: symmetric hyperbolicity, live gauges and dynamic control of the constraints
We present three-dimensional simulations of Einstein equations implementing a
symmetric hyperbolic system of equations with dynamical lapse. The numerical
implementation makes use of techniques that guarantee linear numerical
stability for the associated initial-boundary value problem. The code is first
tested with a gauge wave solution, where rather larger amplitudes and for
significantly longer times are obtained with respect to other state of the art
implementations. Additionally, by minimizing a suitably defined energy for the
constraints in terms of free constraint-functions in the formulation one can
dynamically single out preferred values of these functions for the problem at
hand. We apply the technique to fully three-dimensional simulations of a
stationary black hole spacetime with excision of the singularity, considerably
extending the lifetime of the simulations.Comment: 21 pages. To appear in PR
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