4,375 research outputs found
Blazes: Coordination Analysis for Distributed Programs
Distributed consistency is perhaps the most discussed topic in distributed
systems today. Coordination protocols can ensure consistency, but in practice
they cause undesirable performance unless used judiciously. Scalable
distributed architectures avoid coordination whenever possible, but
under-coordinated systems can exhibit behavioral anomalies under fault, which
are often extremely difficult to debug. This raises significant challenges for
distributed system architects and developers. In this paper we present Blazes,
a cross-platform program analysis framework that (a) identifies program
locations that require coordination to ensure consistent executions, and (b)
automatically synthesizes application-specific coordination code that can
significantly outperform general-purpose techniques. We present two case
studies, one using annotated programs in the Twitter Storm system, and another
using the Bloom declarative language.Comment: Updated to include additional materials from the original technical
report: derivation rules, output stream label
Ostracism and the Provision of a Public Good, Experimental Evidence
We analyze the effects of ostracism on cooperation in a linear public good experiment. Our results show that introducing ostracism increases contributions. Despite reductions in group size due to ostracism, the net effect on earnings is positive and significant.Experiment, Public Good, Ostracism
Isotropic-nematic phase equilibria of polydisperse hard rods: The effect of fat tails in the length distribution
We study the phase behaviour of hard rods with length polydispersity, treated
within a simplified version of the Onsager model. We give a detailed
description of the unusual phase behaviour of the system when the rod length
distribution has a "fat" (e.g. log-normal) tail up to some finite cutoff. The
relatively large number of long rods in the system strongly influences the
phase behaviour: the isotropic cloud curve, which defines the where a nematic
phase first occurs as density is increased, exhibits a kink; at this point the
properties of the coexisting nematic shadow phase change discontinuously. A
narrow three-phase isotropic-nematic-nematic coexistence region exists near the
kink in the cloud curve, even though the length distribution is unimodal. A
theoretical derivation of the isotropic cloud curve and nematic shadow curve,
in the limit of large cutoff, is also given. The two curves are shown to
collapse onto each other in the limit. The coexisting isotropic and nematic
phases are essentially identical, the only difference being that the nematic
contains a larger number of the longest rods; the longer rods are also the only
ones that show any significant nematic ordering. Numerical results for finite
but large cutoff support the theoretical predictions for the asymptotic scaling
of all quantities with the cutoff length.Comment: 21 pages, 13 figure
The importance of regional factors for the income distribution in Austria
Series: IIR-Forschun
Alterations in the cellular DNA and protein content determined by flow cytometry as indicators for chemically induced structural and numerical chromosome aberrations
Cellular DNA and protein content were determined simultaneously in freshly isolated fibroblast-like rat cells by flow cytometry. After exposure to doxorubicin, nitrofurantoin, propranolol and practolol at a low, tissue like oxygen concentration (5% O2), drug-induced alterations in cell cycle kinetics, in the distribution of DNA and in the protein content of G1-phase cells (nucleus/cytoplasm ratio) were analysed. Optimal exposure time (5 or 24 h) and recovery interval (24 or 48 h) were determined. Variation in the exposure time and recovery period can affect cell cycle kinetics both qualitatively and quantitatively, whereas the distribution of DNA and protein content are affected quantitatively only. A 24-h exposure combined with a 24-h recovery period proved to be the most efficient approach. Each of the tested chemicals induced a specific, dose-dependent pattern of altered cellular DNA and protein content. Comparison with results obtained in other genotoxicity tests, and with data reported earlier, showed that this two-parameter protocol can be used to recognize and to characterize chemicals as clastogens, or as compounds with a combined cytostatic/clastogenic activity, or as spindle-poison-like compound
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