322 research outputs found
Building A High Performance Parallel File System Using Grid Datafarm and ROOT I/O
Sheer amount of petabyte scale data foreseen in the LHC experiments require a
careful consideration of the persistency design and the system design in the
world-wide distributed computing. Event parallelism of the HENP data analysis
enables us to take maximum advantage of the high performance cluster computing
and networking when we keep the parallelism both in the data processing phase,
in the data management phase, and in the data transfer phase. A modular
architecture of FADS/ Goofy, a versatile detector simulation framework for
Geant4, enables an easy choice of plug-in facilities for persistency
technologies such as Objectivity/DB and ROOT I/O. The framework is designed to
work naturally with the parallel file system of Grid Datafarm (Gfarm).
FADS/Goofy is proven to generate 10^6 Geant4-simulated Atlas Mockup events
using a 512 CPU PC cluster. The data in ROOT I/O files is replicated using
Gfarm file system. The histogram information is collected from the distributed
ROOT files. During the data replication it has been demonstrated to achieve
more than 2.3 Gbps data transfer rate between the PC clusters over seven
participating PC clusters in the United States and in Japan.Comment: Talk from the 2003 Computing in High Energy and Nuclear Physics
(CHEP03), La Jolla, Ca, USA, March 2003, 4 pages, PDF. PSN TUDT01
On Planetary Companions to the MACHO-98-BLG-35 Microlens Star
We present observations of microlensing event MACHO-98-BLG-35 which reached a
peak magnification factor of almost 80. These observations by the Microlensing
Planet Search (MPS) and the MOA Collaborations place strong constraints on the
possible planetary system of the lens star and show intriguing evidence for a
low mass planet with a mass fraction . A giant planet with is excluded from 95%
of the region between 0.4 and 2.5 from the lens star, where is the
Einstein ring radius of the lens. This exclusion region is more extensive than
the generic "lensing zone" which is . For smaller mass planets,
we can exclude 57% of the "lensing zone" for and 14% of
the lensing zone for . The mass fraction corresponds to an Earth mass planet for a lensing star of mass \sim
0.3 \msun. A number of similar events will provide statistically significant
constraints on the prevalence of Earth mass planets. In order to put our limits
in more familiar terms, we have compared our results to those expected for a
Solar System clone averaging over possible lens system distances and
orientations. We find that such a system is ruled out at the 90% confidence
level. A copy of the Solar System with Jupiter replaced by a second Saturn mass
planet can be ruled out at 70% confidence. Our low mass planetary signal (few
Earth masses to Neptune mass) is significant at the confidence
level. If this planetary interpretation is correct, the MACHO-98-BLG-35 lens
system constitutes the first detection of a low mass planet orbiting an
ordinary star without gas giant planets.Comment: ApJ, April 1, 2000; 27 pages including 8 color postscript figure
Space charge in drift chambers operated with the Xe,CO2(15%) mixture
Using prototype modules of the ALICE Transition Radiation Detector we
investigate space charge effects and the dependence of the pion rejection
performance on the incident angle of the ionizing particle. The average pulse
height distributions in the drift chambers operated with the Xe,CO2(15%)
mixture provide quantitative information on the gas gain reduction due to space
charge accumulating during the drift of the primary ionization. Our results
demonstrate that the pion rejection performance of a TRD is better for tracks
which are not at normal incidence to the anode wires. We present detailed
simulations of detector signals, which reproduce the measurements and lend
strong support to our interpretation of the measurements in terms of space
charge effects.Comment: 18 pages, 10 figures, accepted for publication in Nucl.Instrum.Meth.
A. Data files available at http://www-alice.gsi.de/tr
Measurement of tau polarization in e+ e- annihilation at sqrt{s}=58 GeV
The polarization of tau leptons in the reaction e+ e- --> tau+ tau- has been
measured using a e+e- collider, TRISTAN, at the center-of-mass energy of 58
GeV. From the kinematical distributions of daughter particles in tau --> e nu
nu-bar, mu nu nu-bar, rho nu or pi(K) nu decays, the average polarization of
tau- and its forward-backward asymmetry have been evaluated to be 0.012 +-
0.058 and 0.029 +- 0.057, respectively.Comment: 18 pages, 5 figure
New insight into kinetics behavor of the structural formation process in Agar gelation
A time-resolved experimental study on the kinetics and relaxation of the
structural formation process in gelling Agar-water solutions was carried out
using our custom-built torsion resonator. The study was based on measurements
of three naturally cooled solutions with agar concentrations of 0.75%, 1.0% and
2.0% w/w. It was found that the natural-cooling agar gelation process could be
divided into three stages, sol stage (Stage I), gelation zone (Stage II) and
gel stage (Stage III), based on the time/temperature evolutions of the
structural development rate (SDR). An interesting fluctuant decaying behavior
of SDR was observed in Stage II and III, indicative of a sum of multiple
relaxation processes and well described by a multiple-order Gaussisn-like
equation: . More interestingly, the temperature dependences of the fitted
values of Wn in Stage II and Stage III were found to follow the different
Arrhenius laws, with different activation energies of EaII= 39-74 KJ/mol and
EaIII~7.0 KJ/mol. The two different Arrhenius-like behaviors respectively
suggest that dispersions in Stage II be attributed to the relaxation of the
self-assembly of agar molecules or the growth of junction zones en route to
gelation, in which the formation or fission of hydrogen bonding interactions
plays an important role; and that dispersions in Stage III be attributed to the
relaxation dynamics of water released from various size domains close to the
domain of the viscous flow of water during the syneresis process.Comment: 24 pages, 4 figures, 1 tabl
Measurement and comparison of individual external doses of high-school students living in Japan, France, Poland and Belarus -- the "D-shuttle" project --
Twelve high schools in Japan (of which six are in Fukushima Prefecture), four
in France, eight in Poland and two in Belarus cooperated in the measurement and
comparison of individual external doses in 2014. In total 216 high-school
students and teachers participated in the study. Each participant wore an
electronic personal dosimeter "D-shuttle" for two weeks, and kept a journal of
his/her whereabouts and activities. The distributions of annual external doses
estimated for each region overlap with each other, demonstrating that the
personal external individual doses in locations where residence is currently
allowed in Fukushima Prefecture and in Belarus are well within the range of
estimated annual doses due to the background radiation level of other
regions/countries
Belle II Technical Design Report
The Belle detector at the KEKB electron-positron collider has collected
almost 1 billion Y(4S) events in its decade of operation. Super-KEKB, an
upgrade of KEKB is under construction, to increase the luminosity by two orders
of magnitude during a three-year shutdown, with an ultimate goal of 8E35 /cm^2
/s luminosity. To exploit the increased luminosity, an upgrade of the Belle
detector has been proposed. A new international collaboration Belle-II, is
being formed. The Technical Design Report presents physics motivation, basic
methods of the accelerator upgrade, as well as key improvements of the
detector.Comment: Edited by: Z. Dole\v{z}al and S. Un
Microvascular engineering in perfusion culture: immunohistochemistry and CLSM findings
BACKGROUND: One of the most challenging problems in tissue engineering is the establishment of vascular supply. A possible approach might be the engineering of microvasculature in vitro and the supply by engineered feeder vessels. METHODS: An in vitro model for a small-diameter vessel was developed and made from adipose tissue stromal cells and human umbilical vein endothelial cells in a tube-like gelatine scaffold. The number of "branches" emerging from the central lumen and the morphology of the central lumen of the vessel equivalent were assessed after 16 days of either pulsatile perfusion culture or culture in rotating containers by evaluation of immunohistochemically stained sections (n = 6 pairs of cultures). Intramural capillary network formation was demonstrated in five experiments with confocal laser scanning microscopy. RESULTS: Perfused specimens showed a round or oval lumen lined by a single layer of endothelial cells, whereas following rotation culture the lumen tended to collapse. Confocal laser scanning microscopy showed more extended network formation in perfused specimens as compared to specimens after rotation culture. Partially highly interconected capillary-like networks were imaged which showed orientation around the central lumen. Perfused specimens exhibited significantly more branches emerging from the central lumen. There were, however, hardly any capillary branches crossing the whole vessel wall. CONCLUSION: Pulsatile perfusion supports the development of vascular networks with physiological appearance. Advances in reactor development, acquisition of functional data and imaging procedures are however necessary in order to attain the ultimate goal of a fully functional engineered supplying vessel
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