10,009 research outputs found
3D Simulation of Convection and Spectral Line Formation in A-type Stars
We present first realistic numerical simulations of 3D radiative convection
in the surface layers of main sequence A-type stars with Teff = 8000 K and 8500
K, log g = 4.4 and 4.0, recently performed with the CO5BOLD radiation
hydrodynamics code. The resulting models are used to investigate the structure
of the H+HeI and the HeII convection zones in comparison with the predictions
of local and non-local convection theories, and to determine the amount of
"overshoot" into the stable layers below the HeII convection zone. The
simulations also predict how the topology of the photospheric granulation
pattern changes from solar to A-type star convection. The influence of the
photospheric temperature fluctuations and velocity fields on the shape of
spectral lines is demonstrated by computing synthetic line profiles and line
bisectors for some representative examples, allowing us to confront the 3D
model results with observations.Comment: 5 pages, 6 figures (17 figure files), 1 Tabl
Individual Microscopic Results Of Bottleneck Experiments
This contribution provides microscopic experimental study of pedestrian
motion in front of the bottleneck, explains the high variance of individual
travel time by the statistical analysis of trajectories. The analysis shows
that this heterogeneity increases with increasing occupancy. Some participants
were able to reach lower travel time due more efficient path selection and more
aggressive behavior within the crowd. Based on this observations, linear model
predicting travel time with respect to the aggressiveness of pedestrian is
proposed.Comment: Submitted to Traffic and Granullar Flow 2015, Springe
A comparative analysis of East and West German labor markets before and after unification
This paper uses micro data to analyze the wage structures in East Germany and West Germany before and after unification. In 1988, the wage distribution in East Germany was much more compressed than in West Germany or in the U.S. Since the collapse of Communism and unification with West Germany, however, the wage structure in eastern Germany has changed considerably. In particular, wage variation has increased, the payoff to education has decreased slightly, industry differentials have expanded, and the white collar premium has increased. Although average wage growth has been remarkably high in eastern Germany, individual variation in wage growth is similar to typical western levels. The wage structure of east Germans who work in west Germany resembles the wage structure of native west Germans in some respects, but the experience-earnings profile is flat. --
Cotorsion torsion triples and the representation theory of filtered hierarchical clustering
We give a full classification of representation types of the subcategories of
representations of an rectangular grid with monomorphisms (dually,
epimorphisms) in one or both directions, which appear naturally in the context
of clustering as two-parameter persistent homology in degree zero. We show that
these subcategories are equivalent to the category of all representations of a
smaller grid, modulo a finite number of indecomposables. This equivalence is
constructed from a certain cotorsion torsion triple, which is obtained from a
tilting subcategory generated by said indecomposables.Comment: 39 pages; corrected the lists appearing in Cor. 1.6 and minor changes
throughou
Thermodynamics of polymer adsorption to a flexible membrane
We analyze the structural behavior of a single polymer chain grafted to an
attractive, flexible surface. Our model is composed of a coarse-grained
bead-and-spring polymer and a tethered membrane. By means of extensive parallel
tempering Monte Carlo simulations it is shown that the system exhibits a rich
phase behavior ranging from highly ordered, compact to extended random coil
structures and from desorbed to completely adsorbed or even partially embedded
conformations. These findings are summarized in a pseudophase diagram
indicating the predominant class of conformations as a function of the external
parameters temperature and polymer-membrane interaction strength. By comparison
with adsorption to a stiff membrane surface it is shown that the flexibility of
the membrane gives rise to qualitatively new behavior such as stretching of
adsorbed conformations
- …