10,966 research outputs found
Materials for electrochemical cell separators Summary report
Asbestos and other candidate materials for electrochemical cell separator
Interaktionen zwischen Genotyp und Ort sind ein Vorteil von lokaler Züchtung von Ackerbohnen (Vicia faba L.)
Organic farming is based on low productivity environments regarding the restricted supply of inputs. Thus, to maximize the response of selection, the local breeding approach was put forward for organic agriculture. To analyse this approach, efforts of organic farmers and scientists were combined in a pertinent, participatory breeding approach using spring faba bean as crop. A set of genotypes with different levels of heterozygosity and heterogeneity were tested in four organic farms and one conventional location. Results for grain yield showed that the genotype-location interaction was highly significant and contributed to a large extent to the yield variation. The findings indicated that indeed local breeding programs could give greater genetic gains for organic cropping systems than traditional, formal plant breeding programs
Shadowing and Absorption Effects on J/psi Production in dA Collisions
We study medium modifications of J/psi production in cold nuclear media in
deuterium-nucleus collisions. We discuss several parameterizations of the
modifications of the parton densities in the nucleus, known as shadowing, an
initial-state effect. We also include absorption of the produced J/psi by
nucleons, a final-state effect. Both spatially homogeneous and inhomogeneous
shadowing and absorption are considered. We use the number of binary
nucleon-nucleon collisions as a centrality measure. Results are presented for
d+Au collisions at sqrt{S_{NN}} = 200 GeV and for d+Pb collisions at
sqrt{S_{NN}} = 6.2 TeV. To contrast the centrality dependence in pA and dA
collisions, we also present pPb results at sqrt{S_{NN}} = 8.8 TeV.Comment: 22 pages, 11 figures, uses revte
Parton densities and structure functions at next-to-next-to-leading order and beyond
We summarize recent results on the evolution of unpolarized parton densities
and deep-inelastic structure functions in massless perturbative QCD. Due to
last year's extension of the integer-moment calculations of the three-loop
splitting functions, the NNLO evolution of the parton distributions can now be
performed reliably at momentum fractions x >= 10^-4, facilitating a
considerably improved theoretical accuracy of their extraction from data on
deep-inelastic scattering. The NNLO corrections are not dominated, at relevant
values of x, by their leading small-x terms. At large x the splitting-function
series converges very rapidly, hence, employing results on the three-loop
coefficient functions, the structure functions can be analysed at N^3LO for x >
10^-2. The resulting values for alpha_s do not significantly change beyond
NNLO, their renormalization scale dependence reaches about +-1% at N^3LO.Comment: 10 pages, LaTeX, 6 figures. Talk presented at the workshops `New
Trends in HERA Physics 2001', Ringberg Castle (Germany), June 2001 and `DIS
2001', Bologna (Italy), April 2001. To appear, slightly shortened in the
latter case, in the proceeding
NNLO evolution of deep-inelastic structure functions: the singlet case
We study the next-to-next-to-leading order (NNLO) evolution of flavour
singlet parton densities and structure functions in massless perturbative QCD.
Present information on the corresponding three-loop splitting functions is used
to derive parametrizations of these quantities, including Bjorken-x dependent
estimates of their residual uncertainties. Compact expressions are also
provided for the exactly known, but in part rather lengthy two-loop singlet
coefficient functions. The size of the NNLO corrections and their effect on the
stability under variations of the renormalization and mass-factorizations
scales are investigated. Except for rather low values of the scales, the
residual uncertainty of the three-loop splitting functions does not lead to
relevant effects for x > 10^-3. Inclusion of the NNLO contributions
considerably reduces the theoretical uncertainty of determinations of the quark
and gluon densities from deep-inelastic structure functions.Comment: 31 pages, LaTeX, 14 eps-figure
The stability theory of solutions to partial differential equations - A bibliographical survey
Bibliographical survey of research on stability theory of solutions to partial differential equation
Study of Production in GeV and Collisions in PHENIX
measurements in and collisions serve as crucial
references to understand the production in collisions at RHIC
where quark gluon plasma (QGP) is expected to be formed. They also provide
important clues to study various interesting phenomena such as the gluon
shadowing and color glass condensate. We report the latest results from PHENIX
experiment on production in and collisions at forward,
backward and midrapidity.Comment: 4pages, 6 figures, proceeding of the 18th International Conference on
Nucleus-Nucleus Collisions (QM2005), Aug.4-9, Budapest, Hungar
The existence and stability of nonlinear wave equations
Second order nonlinear wave equation solution on Hilbert space with stability and uniquenes
Event-by-event study of prompt neutrons from 239Pu(n,f)
Employing a recently developed Monte Carlo model, we study the fission of
240Pu induced by neutrons with energies from thermal to just below the
threshold for second chance fission. Current measurements of the mean number of
prompt neutrons emitted in fission, together with less accurate measurements of
the neutron energy spectra, place remarkably fine constraints on predictions of
microscopic calculations. In particular, the total excitation energy of the
nascent fragments must be specified to within 1 MeV to avoid disagreement with
measurements of the mean neutron multiplicity. The combination of the Monte
Carlo fission model with a statistical likelihood analysis also presents a
powerful tool for the evaluation of fission neutron data. Of particular
importance is the fission spectrum, which plays a key role in determining
reactor criticality. We show that our approach can be used to develop an
estimate of the fission spectrum with uncertainties several times smaller than
current experimental uncertainties for outgoing neutron energies up to 2 MeV.Comment: 17 pages, 20 figure
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