36 research outputs found

    Modern digital technologies and telecommunications mechanisms in the implementation of socio-economic policy at the local and regional level

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    The purpose of the work is to modernize the organizational and economic support of the regional economy management processes based on digital technologie

    Event-by-Event Fluctuations in Particle Multiplicities and Transverse Energy Produced in 158.A GeV Pb+Pb collisions

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    Event-by-event fluctuations in the multiplicities of charged particles and photons, and the total transverse energy in 158A\cdot A GeV Pb+Pb collisions are studied for a wide range of centralities. For narrow centrality bins the multiplicity and transverse energy distributions are found to be near perfect Gaussians. The effect of detector acceptance on the multiplicity fluctuations has been studied and demonstrated to follow statistical considerations. The centrality dependence of the charged particle multiplicity fluctuations in the measured data has been found to agree reasonably well with those obtained from a participant model. However for photons the multiplicity fluctuations has been found to be lower compared to those obtained from a participant model. The multiplicity and transverse energy fluctuations have also been compared to those obtained from the VENUS event generator.Comment: To appear in Physical Review C; changes : more detailed discussion on errors and few figures modifie

    Suppression of High-p_T Neutral Pion Production in Central Pb+Pb Collisions at sqrt{s_NN} = 17.3 GeV Relative to p+C and p+Pb Collisions

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    Neutral pion transverse momentum spectra were measured in p+C and p+Pb collisions at sqrt{s_NN} = 17.4 GeV at mid-rapidity 2.3 < eta_lab < 3.0 over the range 0.7< p_T < 3.5 GeV/c. The spectra are compared to pi0 spectra measured in Pb+Pb collisions at sqrt{s_NN} = 17.3 GeV in the same experiment. For a wide range of Pb+Pb centralities (N_part < 300) the yield of pi0's with p_T > 2 GeV/c is larger than or consistent with the p+C or p+Pb yields scaled with the number of nucleon-nucleon collisions (N_coll), while for central Pb+Pb collisions with N_part > 350 the pi0 yield is suppressed.Comment: 5 pages, 4 figure

    Pion Freeze-Out Time in Pb+Pb Collisions at 158 A GeV/c Studied via pi-/pi+ and K-/K+ Ratios

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    The effect of the final state Coulomb interaction on particles produced in Pb+Pb collisions at 158 A GeV/c has been investigated in the WA98 experiment through the study of the pi-/pi+ and K-/K+ ratios measured as a function of transverse mass. While the ratio for kaons shows no significant transverse mass dependence, the pi-/pi+ ratio is enhanced at small transverse mass values with an enhancement that increases with centrality. A silicon pad detector located near the target is used to estimate the contribution of hyperon decays to the pi-/pi+ ratio. The comparison of results with predictions of the RQMD model in which the Coulomb interaction has been incorporated allows to place constraints on the time of the pion freeze-out.Comment: 9 pages, 12 figure

    Robust estimation of bacterial cell count from optical density

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    Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals &lt;1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

    Centrality dependence of charged-neutral particle fluctuations in 158A GeV 208Pb+208Pb^{208}Pb + ^{208}Pb collisions

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    Results on the study of localized fluctuations in the multiplicity of charged particles and photons produced in 158A GeV/c Pb+Pb collisions are presented for varying centralities. The charged versus neutral particle multiplicity correlations in common phase space regions of varying azimuthal sizes are analyzed by two different methods. Various types of mixed events are constructed to probe fluctuations arising from different sources. The measured results are compared to those from simulations and from mixed events. The comparison indicates the presence of nonstatistical fluctuations in both the charged particle and photon multiplicities in limited azimuthal regions. However, no correlated charged-neutral fluctuations, a possible signature of formation of disoriented chiral condensates, are observed. An upper limit on the production of disoriented chiral condensates is set

    One-, Two- and Three-Particle Distributions from 158 A GeV/c Central Pb+Pb Collisions

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    Several hadronic observables have been studied in central 158 A GeV Pb+Pb collisions using data measured by the WA98 experiment at CERN: single negative pion and kaon production, as well as two- and three-pion interferometry. The Wiedemann-Heinz hydrodynamical model has been fitted to the pion spectrum, giving an estimate of the temperature and transverse flow velocity. Bose-Einstein correlations between two identified negative pions have been analysed as a function of kT, using two different parameterizations. The results indicate that the source does not have a strictly boost invariant expansion or spend time in a long-lived intermediate phase. A comparison between data and a hydrodynamical based simulation shows very good agreement for the radii parameters as a function of kT. The pion phase-space density at freeze-out has been measured and agrees well with the Tomasik-Heinz model. A large pion chemical potential close to the condensation limit of the pion mass seems to be excluded. The three-pion Bose-Einstein interferometry shows a substantial contribution of the genuine three-pion correlation, but not quite as large as expected for a fully chaotic and symmetric source

    K-stationarity and wavelets

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    Measurements of direct photon production in p+Pb and p+C collisions at sNN=17.4GeV\sqrt{s_\mathrm{NN}} = 17.4\mathrm{GeV} are presented. Upper limits on the direct photon yield as a function of pTp_\mathrm{T} are derived and compared to the results for Pb+Pb collisions at sNN=17.3\sqrt{s_\mathrm{NN}} = 17.3 GeV. The production of the η\eta meson, which is an important input to the direct photon signal extraction, has been determined in the η2γ\eta \rightarrow 2\gamma channel for p+C collisions at sNN=17.4GeV\sqrt{s_\mathrm{NN}} = 17.4\mathrm{GeV}
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