400 research outputs found

    Correlation of transverse momentum and multiplicity in a superposition model of nucleus-nucleus collisions

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    In p-p collisions the average transverse momentum is known to be correlated with the multiplicity of produced particles. The correlation is shown to survive in a superposition model of nucleus-nucleus collisions. When properly parameterized, the correlation strength appears to be independent of the collision centrality - it is the same in p-p and central A-A collisions. However, the correlation is strongly suppressed by the centrality fluctuations.Comment: 7 pages, 2 figures, minor corrections, to appear in Phys. Rev.

    Fluctuations, strangeness and quasi-quarks in heavy-ion collisions from lattice QCD

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    We report measurements of diagonal susceptibilities for the baryon number, chi_B, electrical charge, chi_Q, third component of isospin, chi_I, strangeness, chi_S, and hypercharge, chi_Y, as well as the off-diagonal chi_BQ, chi_BY, chi_BS, etc. We show that the ratios of susceptibilities in the high temperature phase are robust variables, independent of lattice spacing, and therefore give predictions for experiments. We also investigate strangeness production and flavour symmetry breaking matrix elements at finite temperature. Finally, we present evidence that in the high temperature phase of QCD the different flavour quantum numbers are excited in linkages which are exactly the same as one expects from quarks. We present some investigations of these quark-like quasi particles

    Flow analysis of the turbine rotor tip seal on a highly rotary test rig

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    Workshop byl částečně podpořen projektem CZ.1.07/2.3.00/20.0139. Tento projekt je spolufinancován Evropským sociálním fondem a státním rozpočtem České republiky

    Applications of Scanning Electron Microscopy and X-Ray Microanalysis in Inner Ear Pathology

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    Surface pathology of inner ear structures so far described in detail concern cochlear and vestibular hair cells and the stria vascularis. In man, surgical intervention into the inner ear is very uncommon and when performed is in general with the primary objective of destroying the diseased peripheral end organs. The vast majority of inner ear tissue available for use with scanning electron microscopy (SEM) is therefore obtained from animals. The present paper reviews the progression of surface pathology caused by aminoglycoside antibiotics, acoustic overstimulation and in a guinea pig strain with genetic inner ear disease. The primary site of onset of surface pathology differs, depending on the underlying cause. Advanced surface pathology shows a similar type of morphological degeneration independent of cause. The combination of SEM and energy dispersive X-ray microanalysis (XRMA) of inner ear pathology has as yet been reported in only three studies, all concerning inner ear fluids or otoconia

    Morphology of sesamoid bones in keyboard musicians

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    Background: The sesamoid bones are small, usually oval bone structures often found in joints and under the tendons. Although their precise function is not fully understood, it is agreed upon that they protect the joints and make movements faster and less energy consuming. Sesamoid bones are found in hands, especially around first, second and fifth metacarpophalangeal joint and the interphalangeal joint of the thumb. Materials and methods: This study compares a group of 32 young musicians to 30 non-musicians of similar age and posture. The hands of the subjects were examined by ultrasound imaging for the presence of sesamoid bones. The results were noted and observed sesamoids were measured. Results: The results seem to prove that although there are no difference in the amount or the location of the sesamoid bones between the musicians and the non-musicians, there is statistically significant tendency for the musicians to have bigger sum of the sesamoid’s volume per hand (Fisher’s test p-value = 0.034 < 0.05). Conclusions: There was also observed an unusually shaped “Bactrian” sesamoid bone at the interphalangeal joint of the thumb in 8 cases in the musicians’ group and 1 case in the control group. All participants with the aforementioned structure were female

    Comment on ``Strangeness enhancement in p+Ap+A and S+A+A interactions at energies near 200 AA GeV"

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    We argue that the recent analysis of strangeness production in nuclear collisions at 200 AA GeV/cc performed by Topor Pop {\it et al.} \cite{To:95} is flawed. The conclusions are based on an erroneous interpretation of the data and the numerical model results. The term ``strangeness enhancement" is used in a misleading way.Comment: 4 pages REVTEX 3.0, no figures; Comment submitted to Physical Review

    Riverine water inflows and the Baltic Sea water volume 1901-1990

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    International audienceAn analysis of riverine outflow into the Baltic Sea is presented for the years 1901 ? 1990. The monthly outflows were calculated from the measurements in a number of representative rivers. The analysis included estimation of seasonal and multi-year characteristics of riverine outflows and periodic structure, as well as stochastic and statistical indicators characterising the influence of riverine water on the variability of the sea level and water volume in the basin. The article presents prognostic characteristics determined using analysis of parametric stochastic processes. The results obtained are related to oceanographic characteristics of the Baltic Sea. Keywords: Baltic volume; Baltic balance; river outflow; river seasonality</p

    Review of Results from the NA49 Collaboration

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    New results of the NA49 collaboration on strange particle production are presented. Rapidity and transverse mass spectra as well as total multiplicities are discussed. The study of their evolution from AGS over SPS to the highest RHIC energy reveals a couple of interesting features. These include a sudden change in the energy dependence of the mt-spectra and of the yields of strange hadrons around 30 AGeV. Both are found to be difficult to be reproduced in a hadronic scenario, but might be an indication for a phase transition to a quark gluon plasma.Comment: 8 pages, 7 figures. Proceedings of the SQM04 conference, Capetow

    Importance of reaction volume in hadronic collisions: Canonical enhancement

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    We study the canonical flavor enhancement arising from exact conservation of strangeness, and charm flavor. Both the theoretical motivation, and the practical consequences are explored. We argue using qualitative theoretical arguments and quantitative evaluation, that this proposal to reevaluate strangeness signature of quark--gluon plasma is not able to explain the majority of available experimental results.Comment: 14 pages including 6 figures, submitted to Journal of Physics G Presented at: Strange Quark Matter, September 2001, Frankfur
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