7,778 research outputs found
Reasons to Ban? The Anti-Burqa Movement in Western Europe
Originally published at http://www.mmg.mpg.de/en/publications/working-papers/2012/
'Our Working Papers are refereed and may be downloaded from this site by individuals, for their own use, subject to the ordinary rules governing the fair use of professional scholarship. Working Papers may be cited without seeking prior permission from the author.
Detection of GRB signals with Fluorescence Detectors
Gamma Ray Bursts are being searched in many ground based experiments
detecting the high energy component (GeV TeV energy range) of the photon
bursts. In this paper, Fluorescence Detectors are considered as possible
candidate devices for these searches. It is shown that the GRB photons induce
fluorescence emission of UV photons on a wide range of their spectrum. The
induced fluorescence flux is dominated by GRB photons from 0.1 to about 100 MeV
and, once the extinction through the atmosphere is taken into account, it is
distributed over a wide angular region. This flux can be detected through a
monitor of the diffuse photon flux, provided that its maximum value exceeds a
threshold value, that is primarily determined by the sky brightness above the
detector. The feasibility of this search and the expected rates are discussed
on the basis of the current GRB observations and the existing fluorescence
detectors.Comment: 16 pages 9 eps figure
Hydrologically induced slope deformations detected by GPS and clinometric surveys in the Cansiglio Plateau, southern Alps
Changes in groundwater or surface water level may cause observable deformation of the drainage basins in different ways. We describe an active slope deformation monitored with GPS and tiltmeter stations in a karstic limestone plateau in southeastern Alps (Cansiglio Plateau). The observed transient GPS deformation clearly correlates with the rainfall. Both GPS and tiltmeter equipments react instantly to heavy rains displaying abrupt offsets, but with different time constants, demonstrating the response to different catchment volumes. The GPS movement is mostly confined in the horizontal plane (SSW direction) showing a systematic tendency to rebound in the weeks following the rain. Four GPS stations concur to define a coherent deformation pattern of a wide area (12
75km2), concerning the whole southeastern slope of the plateau. The plateau expands and rebounds radially after rain by an amount up to a few centimeters and causing only small vertical deformation. The effect is largest where karstic features are mostly developed, at the margin of the plateau where a thick succession of Cretaceous peritidal carbonates faces the Venetian lowland. Acouple of tiltmeters installed in a cave at the top of the plateau, detect a much faster deformation, that has the tendency to rebound in less than 6h. The correlation to rainfall is less straightforward, and shows a more complex behavior during rainy weather. The different responses demonstrate a fast hydrologic flow in the more permeable epikarst for the tiltmeters, drained by open fractures and fissures in the neighborhood of the cave, and a rapid tensile dislocation of the bedrock measured at the GPS stations that affect the whole slope of the mountain. In the days following the rain, both tiltmeter and GPS data show a tendency to retrieve the displacement which is consistent with the phreatic discharge curve. We propose that hydrologically active fractures recharged by rainfall are the most likely features capable to induce the observed strain variations
VisIVOWeb: A WWW Environment for Large-Scale Astrophysical Visualization
This article presents a newly developed Web portal called VisIVOWeb that aims
to provide the astrophysical community with powerful visualization tools for
large-scale data sets in the context of Web 2.0. VisIVOWeb can effectively
handle modern numerical simulations and real-world observations. Our
open-source software is based on established visualization toolkits offering
high-quality rendering algorithms. The underlying data management is discussed
with the supported visualization interfaces and movie-making functionality. We
introduce VisIVOWeb Network, a robust network of customized Web portals for
visual discovery, and VisIVOWeb Connect, a lightweight and efficient solution
for seamlessly connecting to existing astrophysical archives. A significant
effort has been devoted for ensuring interoperability with existing tools by
adhering to IVOA standards. We conclude with a summary of our work and a
discussion on future developments
The final fate of spherical inhomogeneous dust collapse II: Initial data and causal structure of singularity
Further to results in [9], pointing out the role of initial density and
velocity distributions towards determining the final outcome of spherical dust
collapse, the causal structure of singularity is examined here in terms of
evolution of the apparent horizon. We also bring out several related features
which throw some useful light towards understanding the nature of this
singularity, including the behaviour of geodesic families coming out and some
aspects related to the stability of singularity.Comment: Latex file, uses epsf.sty, 15 pages and 3 eps figures. Paragraph on
role of smooth functions rewritten. Four references added. To appear in
Classical & Quantum Gravit
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