1,704 research outputs found
Zur Sterblichkeitsdifferenz von Männern im Ost-West-Vergleich
Die Untersuchung der Sterblichkeit der sozialversicherungspflichtigen Beschäftigten des Jahres 2004 deckt die Gründe für die Unterschiede der Lebenserwartung bei Männern im Ost-West-Vergleich auf. Es wird gezeigt, dass die bestehenden strukturellen Unterschiede des Arbeitsmarktes in Ost- und Westdeutschland die Lebenserwartungsdifferenz bei Männern im Alter bis 65 Jahre erklären können. Die multivariate Analyse von Individualdaten der 20 Millionen "Aktiv Versicherten" (Datensätze des Forschungsdatenzentrum der Rentenversicherung (FDZ-RV)) zeigt, dass die Berücksichtigung der Merkmale Beschäftigung, Arbeitslosigkeit, Selbstständigkeit, Versicherungsart und Staatsbürgerschaft geeignet sind, eine bis zu 30 % erhöhte Sterblichkeit der ostdeutschen Männer im Altersbereich von 35 bis 55 Jahre zu erklären. Die Differenzen sind ein Ergebnis der unterschiedlichen Arbeitsmarktlage und der damit verbundenen kumulativen Migration in den letzten 30 Jahren.Germany, Germany (Alte Bundesländer), Germany (Neue Bundesländer), life expectancy, male mortality, unemployment, working-age population
The H.E.S.S. central data acquisition system
The High Energy Stereoscopic System (H.E.S.S.) is a system of Imaging
Atmospheric Cherenkov Telescopes (IACTs) located in the Khomas Highland in
Namibia. It measures cosmic gamma rays of very high energies (VHE; >100 GeV)
using the Earth's atmosphere as a calorimeter. The H.E.S.S. Array entered Phase
II in September 2012 with the inauguration of a fifth telescope that is larger
and more complex than the other four. This paper will give an overview of the
current H.E.S.S. central data acquisition (DAQ) system with particular emphasis
on the upgrades made to integrate the fifth telescope into the array. At first,
the various requirements for the central DAQ are discussed then the general
design principles employed to fulfil these requirements are described. Finally,
the performance, stability and reliability of the H.E.S.S. central DAQ are
presented. One of the major accomplishments is that less than 0.8% of
observation time has been lost due to central DAQ problems since 2009.Comment: 17 pages, 8 figures, published in Astroparticle Physic
Electrostatic colloid-membrane complexation
We investigate numerically and on the scaling level the adsorption of a
charged colloid on an oppositely charged flexible membrane. We show that the
long ranged character of the electrostatic interaction leads to a wrapping
reentrance of the complex as the salt concentration is varied. The membrane
wrapping depends on the size of the colloid and on the salt concentration and
only for intermediate salt concentration and colloid sizes we find full
wrapping. From the scaling model we derive simple relations for the phase
boundaries between the different states of the complex, which agree well with
the numerical minimization of the free energy.Comment: 7 page, 11 figure
Spatially resolved X-ray spectroscopy and modeling of the nonthermal emission of the PWN in G0.9+0.1
We performed a spatially resolved spectral X-ray study of the pulsar wind
nebula (PWN) in the supernova remnant G0.9+0.1. Furthermore we modeled its
nonthermal emission in the X-ray and very high energy (VHE, E > 100 GeV)
gamma-ray regime. Using Chandra ACIS-S3 data, we investigated the east-west
dependence of the spectral properties of G0.9+0.1 by calculating hardness
ratios. We analyzed the EPIC-MOS and EPIC-pn data of two on-axis observations
of the XMM-Newton telescope and extracted spectra of four annulus-shaped
regions, centered on the region of brightest emission of the source. A radially
symmetric leptonic model was applied in order to reproduce the observed X-ray
emission of the inner part of the PWN. Using the optimized model parameter
values obtained from the X-ray analysis, we then compared the modeled inverse
Compton (IC) radiation with the published H.E.S.S. gamma-ray data. The spectral
index within the four annuli increases with growing distance to the pulsar,
whereas the surface brightness drops. With the adopted model we are able to
reproduce the characteristics of the X-ray spectra. The model results for the
VHE gamma radiation, however, strongly deviate from the H.E.S.S. data.Comment: 8 pages, 7 figures, accepted for publication in Astronomy &
Astrophysic
A major electronics upgrade for the H.E.S.S. Cherenkov telescopes 1-4
The High Energy Stereoscopic System (H.E.S.S.) is an array of imaging
atmospheric Cherenkov telescopes (IACTs) located in the Khomas Highland in
Namibia. It consists of four 12-m telescopes (CT1-4), which started operations
in 2003, and a 28-m diameter one (CT5), which was brought online in 2012. It is
the only IACT system featuring telescopes of different sizes, which provides
sensitivity for gamma rays across a very wide energy range, from ~30 GeV up to
~100 TeV. Since the camera electronics of CT1-4 are much older than the one of
CT5, an upgrade is being carried out; first deployment was in 2015, full
operation is planned for 2016. The goals of this upgrade are threefold:
reducing the dead time of the cameras, improving the overall performance of the
array and reducing the system failure rate related to aging. Upon completion,
the upgrade will assure the continuous operation of H.E.S.S. at its full
sensitivity until and possibly beyond the advent of CTA. In the design of the
new components, several CTA concepts and technologies were used and are thus
being evaluated in the field: The upgraded read-out electronics is based on the
NECTAR readout chips; the new camera front- and back-end control subsystems are
based on an FPGA and an embedded ARM computer; the communication between
subsystems is based on standard Ethernet technologies. These hardware solutions
offer good performance, robustness and flexibility. The design of the new
cameras is reported here.Comment: Proceedings of the 34th International Cosmic Ray Conference, 30 July-
6 August, 2015, The Hague, The Netherland
S-COL: A Copernican turn for the development of flexibly reusable collaboration scripts
Collaboration scripts are usually implemented as parts of a particular collaborative-learning platform. Therefore, scripts of demonstrated effectiveness are hardly used with learning platforms at other sites, and replication studies are rare. The approach of a platform-independent description language for scripts that allows for easy implementation of the same script on different platforms has not succeeded yet in making the transfer of scripts feasible. We present an alternative solution that treats the problem as a special case of providing support on top of diverse Web pages: In this case, the challenge is to trigger support based on the recognition of a Web page as belonging to a specific type of functionally equivalent pages such as the search query form or the results page of a search engine. The solution suggested has been implemented by means of a tool called S-COL (Scripting for Collaborative Online Learning) and allows for the sustainable development of scripts and scaffolds that can be used with a broad variety of content and platforms. The tool’s functions are described. In order to demonstrate the feasibility and ease of script reuse with S-COL, we describe the flexible re-implementation of a collaboration script for argumentation in S-COL and its adaptation to different learning platforms. To demonstrate that a collaboration script implemented in S-COL can actually foster learning, an empirical study about the effects of a specific script for collaborative online search on learning activities is presented. The further potentials and the limitations of the S-COL approach are discussed
Analyzing collaborative learning processes automatically
In this article we describe the emerging area of text classification research focused on the problem of collaborative learning process analysis both from a broad perspective and more specifically in terms of a publicly available tool set called TagHelper tools. Analyzing the variety of pedagogically valuable facets of learners’ interactions is a time consuming and effortful process. Improving automated analyses of such highly valued processes of collaborative learning by adapting and applying recent text classification technologies would make it a less arduous task to obtain insights from corpus data. This endeavor also holds the potential for enabling substantially improved on-line instruction both by providing teachers and facilitators with reports about the groups they are moderating and by triggering context sensitive collaborative learning support on an as-needed basis. In this article, we report on an interdisciplinary research project, which has been investigating the effectiveness of applying text classification technology to a large CSCL corpus that has been analyzed by human coders using a theory-based multidimensional coding scheme. We report promising results and include an in-depth discussion of important issues such as reliability, validity, and efficiency that should be considered when deciding on the appropriateness of adopting a new technology such as TagHelper tools. One major technical contribution of this work is a demonstration that an important piece of the work towards making text classification technology effective for this purpose is designing and building linguistic pattern detectors, otherwise known as features, that can be extracted reliably from texts and that have high predictive power for the categories of discourse actions that the CSCL community is interested in
The Outer Tracker Detector of the HERA-B Experiment Part I: Detector
The HERA-B Outer Tracker is a large system of planar drift chambers with
about 113000 read-out channels. Its inner part has been designed to be exposed
to a particle flux of up to 2.10^5 cm^-2 s^-1, thus coping with conditions
similar to those expected for future hadron collider experiments. 13
superlayers, each consisting of two individual chambers, have been assembled
and installed in the experiment. The stereo layers inside each chamber are
composed of honeycomb drift tube modules with 5 and 10 mm diameter cells.
Chamber aging is prevented by coating the cathode foils with thin layers of
copper and gold, together with a proper drift gas choice. Longitudinal wire
segmentation is used to limit the occupancy in the most irradiated detector
regions to about 20 %. The production of 978 modules was distributed among six
different laboratories and took 15 months. For all materials in the fiducial
region of the detector good compromises of stability versus thickness were
found. A closed-loop gas system supplies the Ar/CF4/CO2 gas mixture to all
chambers. The successful operation of the HERA-B Outer Tracker shows that a
large tracker can be efficiently built and safely operated under huge radiation
load at a hadron collider.Comment: 28 pages, 14 figure
Aging Studies for the Large Honeycomb Drift Tube System of the Outer Tracker of HERA-B
The HERA-B Outer Tracker consists of drift tubes folded from polycarbonate
foil and is operated with Ar/CF4/CO2 as drift gas. The detector has to stand
radiation levels which are similar to LHC conditions. The first prototypes
exposed to radiation in HERA-B suffered severe radiation damage due to the
development of self-sustaining currents (Malter effect). In a subsequent
extended R&D program major changes to the original concept for the drift tubes
(surface conductivity, drift gas, production materials) have been developed and
validated for use in harsh radiation environments. In the test program various
aging effects (like Malter currents, gain loss due to anode aging and etching
of the anode gold surface) have been observed and cures by tuning of operation
parameters have been developed.Comment: 14 pages, 6 figures, to be published in the Proceedings of the
International Workshop On Aging Phenomena In Gaseous Detectors, 2-5 Oct 2001,
Hamburg, German
Open and Hidden Charm Production in 920 GeV Proton-Nucleus Collisions
The HERA-B collaboration has studied the production of charmonium and open
charm states in collisions of 920 GeV protons with wire targets of different
materials. The acceptance of the HERA-B spectrometer covers negative values of
xF up to xF=-0.3 and a broad range in transverse momentum from 0.0 to 4.8
GeV/c. The studies presented in this paper include J/psi differential
distributions and the suppression of J/psi production in nuclear media.
Furthermore, production cross sections and cross section ratios for open charm
mesons are discussed.Comment: 5 pages, 9 figures, to be published in the proceedings of the 6th
International Conference on Hyperons, Charm & Beauty Hadrons (BEACH04),
Chicago, IL, June 27 - July 3, 200
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