365 research outputs found

    Констpукції з прийменником з як адвербіальні синтаксеми

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    Статья касается проблемы семантического арсенала конструкции из предлогом з как адвербиальной синтаксемы. Характеризуется возможность употребления этой конструкции як адвербиальной синтaксемы. Приводятся примеры функционирования этой конструкции как каузальной, темпоральной и целевой синтаксемы.Стаття стосується проблеми семантичного арсеналу конструкції з прийменником з як адвербіальної синтаксеми. Характеризується можливість вживання цієї конструкції як адвербіальної синтаксеми. Наводяться приклади функціонування цієї конструкції як темпоральної, причинової і цільової синтаксеми.The article concerns the problem of semantic arsenal of construction with as adverbial syntactic units. Is ability of usage in the sentence as adverbial syntactic units is characterized. The examples of the functioning of this construction as temporal causal purpose syntaxems are given

    Die Wertbaumanalyse : Entscheidungshilfe für die Politik

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    For an assessment of the social compatibility of energy systems, it is jmportant to know the criteria by which different social groups evaluate energy systems and thereby identify energy supply seenarios which are more or less desirable with respect to these criteria. The study presented in this volume is an attempt to develop such a catalogue of criteria. Using a technique called "value tree analysis" , a logical system of catagorizing values, concerns and criteria for the evaluation of energy systems was created. This is first clone separately for each important social groups and then jointly in an aggregate system that combines the values and concerns voiced by these groups

    Evaluation of rate law approximations in bottom-up kinetic models of metabolism.

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    BackgroundThe mechanistic description of enzyme kinetics in a dynamic model of metabolism requires specifying the numerical values of a large number of kinetic parameters. The parameterization challenge is often addressed through the use of simplifying approximations to form reaction rate laws with reduced numbers of parameters. Whether such simplified models can reproduce dynamic characteristics of the full system is an important question.ResultsIn this work, we compared the local transient response properties of dynamic models constructed using rate laws with varying levels of approximation. These approximate rate laws were: 1) a Michaelis-Menten rate law with measured enzyme parameters, 2) a Michaelis-Menten rate law with approximated parameters, using the convenience kinetics convention, 3) a thermodynamic rate law resulting from a metabolite saturation assumption, and 4) a pure chemical reaction mass action rate law that removes the role of the enzyme from the reaction kinetics. We utilized in vivo data for the human red blood cell to compare the effect of rate law choices against the backdrop of physiological flux and concentration differences. We found that the Michaelis-Menten rate law with measured enzyme parameters yields an excellent approximation of the full system dynamics, while other assumptions cause greater discrepancies in system dynamic behavior. However, iteratively replacing mechanistic rate laws with approximations resulted in a model that retains a high correlation with the true model behavior. Investigating this consistency, we determined that the order of magnitude differences among fluxes and concentrations in the network were greatly influential on the network dynamics. We further identified reaction features such as thermodynamic reversibility, high substrate concentration, and lack of allosteric regulation, which make certain reactions more suitable for rate law approximations.ConclusionsOverall, our work generally supports the use of approximate rate laws when building large scale kinetic models, due to the key role that physiologically meaningful flux and concentration ranges play in determining network dynamics. However, we also showed that detailed mechanistic models show a clear benefit in prediction accuracy when data is available. The work here should help to provide guidance to future kinetic modeling efforts on the choice of rate law and parameterization approaches

    Differential directed flow in Au+Au collisions

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    We present experimental data on directed flow in semi-central Au+Au collisions at incident energies from 90 to 400 A MeV. For the first time for this energy domain, the data are presented in a transverse momentum differential way. We study the first order Fourier coefficient v1 for different particle species and establish a gradual change of its patterns as a function of incident energy and for different regions in rapidity.Comment: 5 pages, Latex, 5 eps figures, accepted for publication in Phys. Rev. C (Rapid Communications). Data files available at http://www-linux.gsi.de/~andronic/fopi/v1.htm

    The HADES Tracking System

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    The tracking system of the dielectron spectrometer HADES at GSI Darmstadt is formed out of 24 low-mass, trapezoidal multi-layer drift chambers providing in total about 30 square meter of active area. Low multiple scattering in the in total four planes of drift chambers before and after the magnetic field is ensured by using helium-based gas mixtures and aluminum cathode and field wires. First in-beam performance results are contrasted with expectations from simulations. Emphasis is placed on the energy loss information, exploring its relevance regarding track recognition.Comment: 6 pages, 4 figures, presented at the 10th Vienna Conference on Instrumentation, Vienna, February 2004, to be published in NIM A (special issue

    Strange meson production in Al+Al collisions at 1.9A GeV

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    The production of K+^+, K^- and φ\varphi(1020) mesons is studied in Al+Al collisions at a beam energy of 1.9A GeV which is close or below the production threshold in NN reactions. Inverse slopes, anisotropy parameters, and total emission yields of K±^{\pm} mesons are obtained. A comparison of the ratio of kinetic energy distributions of K^- and K+^+ mesons to the HSD transport model calculations suggests that the inclusion of the in-medium modifications of kaon properties is necessary to reproduce the ratio. The inverse slope and total yield of ϕ\phi mesons are deduced. The contribution to K^- production from ϕ\phi meson decays is found to be [17 ±\pm 3 (stat) 7+2^{+2}_{-7} (syst)] %. The results are in line with previous K±^{\pm} and ϕ\phi data obtained for different colliding systems at similar incident beam energies.Comment: 16 pages, 11 figure

    Isospin dependence of relative yields of K+K^+ and K0K^0 mesons at 1.528 AGeV

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    Results on K+K^+ and K0K^0 meson production in 4496^{96}_{44}Ru + 4496^{96}_{44}Ru and 4096^{96}_{40}Zr + 4096^{96}_{40}Zr collisions at a beam kinetic energy of 1.528AA GeV, measured with the FOPI detector at GSI-Darmstadt, are investigated as a possible probe of isospin effects in high density nuclear matter. The measured double ratio (K+/K0K^+/K^0)Ru_{Ru}/(K+/K0K^+/K^0)Zr_{Zr} is compared to the predictions of a thermal model and a Relativistic Mean Field transport model using two different collision scenarios and under different assumptions on the stiffness of the symmetry energy. We find a good agreement with the thermal model prediction and the assumption of a soft symmetry energy for infinite nuclear matter while more realistic transport simulations of the collisions show a similar agreement with the data but also exhibit a reduced sensitivity to the symmetry term.Comment: 5 pages, 3 figures. accepted for publication in Phys. Rev.

    Two-proton small-angle correlations in central heavy-ion collisions: a beam-energy and system-size dependent study

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    Small-angle correlations of pairs of protons emitted in central collisions of Ca + Ca, Ru + Ru and Au + Au at beam energies from 400 to 1500 MeV per nucleon are investigated with the FOPI detector system at SIS/GSI Darmstadt. Dependences on system size and beam energy are presented which extend the experimental data basis of pp correlations in the SIS energy range substantially. The size of the proton-emitting source is estimated by comparing the experimental data with the output of a final-state interaction model which utilizes either static Gaussian sources or the one-body phase-space distribution of protons provided by the BUU transport approach. The trends in the experimental data, i.e. system-size and beam energy dependences, are well reproduced by this hybrid model. However, the pp correlation function is found rather insensitive to the stiffness of the equation of state entering the transport model calculations.Comment: 9 pages, 8 figures, accepted at Eur. Phys. Journ.

    Centrality dependence of subthreshold ϕ\phi meson production in Ni+Ni collisions at 1.9A GeV

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    We analysed the ϕ\phi meson production in central Ni+Ni collisions at the beam kinetic energy of 1.93A GeV with the FOPI spectrometer and found the production probability per event of [8.6 ± 1.6 (stat)±1.5 (syst)]×104[8.6 ~\pm~ 1.6 ~(\text{stat}) \pm 1.5 ~(\text{syst})] \times 10^{-4}. This new data point allows for the first time to inspect the centrality dependence of the subthreshold ϕ\phi meson production in heavy-ion collisions. The rise of ϕ\phi meson multiplicity per event with mean number of participants can be parameterized by the power function with exponent α=1.8±0.6\alpha = 1.8 \pm 0.6. The ratio of ϕ\phi to K\text{K}^- production yields seems not to depend within the experimental uncertainties on the collision centrality, and the average of measured values was found to be 0.36±0.050.36 \pm 0.05.Comment: 9 pages, 5 figure

    The Λp\bf{\Lambda p} interaction studied via femtoscopy in p + Nb reactions at sNN=3.18 GeV\mathbf{\sqrt{s_{NN}}=3.18} ~\mathrm{\bf{GeV}}

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    We report on the first measurement of pΛp\Lambda and pppp correlations via the femtoscopy method in p+Nb reactions at sNN=3.18 GeV\mathrm{\sqrt{s_{NN}}=3.18} ~\mathrm{GeV}, studied with the High Acceptance Di-Electron Spectrometer (HADES). By comparing the experimental correlation function to model calculations, a source size for pppp pairs of r0,pp=2.02±0.01(stat)0.12+0.11(sys) fmr_{0,pp}=2.02 \pm 0.01(\mathrm{stat})^{+0.11}_{-0.12} (\mathrm{sys}) ~\mathrm{fm} and a slightly smaller value for pΛp\Lambda of r0,Λp=1.62±0.02(stat)0.08+0.19(sys) fmr_{0,\Lambda p}=1.62 \pm 0.02(\mathrm{stat})^{+0.19}_{-0.08}(\mathrm{sys}) ~\mathrm{fm} is extracted. Using the geometrical extent of the particle emitting region, determined experimentally with pppp correlations as reference together with a source function from a transport model, it is possible to study different sets of scattering parameters. The pΛp\Lambda correlation is proven sensitive to predicted scattering length values from chiral effective field theory. We demonstrate that the femtoscopy technique can be used as valid alternative to the analysis of scattering data to study the hyperon-nucleon interaction.Comment: 12 pages, 11 figure
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