Energy and Q^2 dependence of elastic vectormeson production and the proton structure function F_2

In the framework of the Model of the Stochastic Vacuum elastic hadron-hadron scattering, photo- and electroproduction of vectormesons and also F_2(Q^2) can be well described at center of mass energy approximately 20 GeV. The scattering amplitude is derived by smearing the color dipole-dipole scattering, which is calculated nonperturbatively in the Model of the Stochastic Vacuum, with appropriate wavefunctions. For the considered processes the dipoles have extensions in the range of hadron sizes. We now extend this idea to small dipoles and high energies. The energy dependence is modeled in a phenomenological way: we assume that there a two pomerons, the soft- and the hard-pomeron, each being a simple pole in the complex angular plane. We couple dipoles of hadronic size to the soft-pomeron and small dipoles to the hard-pomeron. For small dipoles we take the perturbative gluon exchange into account. By that way we obtain an energy dependent dipole-dipole scattering amplitude which can be used for all the processes with the same parameters. We show that this approach can describe in addition to all the low energy results (20 GeV) also the HERA data for the considered processes in a large energy and Q^2 range. Especially the right transition from the soft to the hard behavior is observed.Comment: 28 pages, LaTex2e, uses graphicx package for eps-figure

Description of elastic vectormeson production and F_2 by two pomerons

Using the Model of the Stochastic Vacuum many diffractive processes have been calculated by investigating the dipole-dipole scattering at a cm-energy of 20 GeV. In this work we extend the calculation to larger energies and small dipoles. We assume that there are two pomerons, the hard- and the soft-pomeron, which cause the different energy dependence for processes dominated by small or large dipoles. The physical processes are obtained by smearing the dipole-dipole amplitude with wavefunctions. For small dipoles the leading perturbative contribution is taken into account. By that way we can describe in addition to the already calculated low energy results (20 GeV) also the HERA data for the considered processes in nearly the whole energy and Q^2 range.Comment: LaTeX2e, 4pp, espcrc2mod.sty (appended, espcrc2 with corrected error), graphicx.sty, 17 eps-figures. Talk presented at QCD98, Montpellier, France (Nucl.Phys.B Proc.Suppl.

Synchronized Mediawiki based analyzer dictionary development

Open-source analyzer dictionary development is being implemented for Skolt Sami, Ingrian, Moksha-Mordvin, etc. in the Helsinki CSC infrastructure; home of the Finnish Kielipankki ’Language Bank’ and Termipankki ’Term Bank’. The proximity of minority-language corpora in need of annotation and the multiple usage of controlled wikimedia-type dictionaries make CSC an attractive site for synchronized transducer dictionary development. The open-source FST develop- ment of Uralic and other minority languages at Giellatekno-Divvun in Tromsø demonstrates a vast potential for reusage of FST-s, only augmented by open- source work in OmorFi, Apertium and Universal Dependency . The initial idea is to allow synchronized editing of Giellatekno xml and CSC wiki structures via github. In addition to allowing for simple lexc LEMMA:STEM CONTINUATION_LEXICON ”TRANS- LATION” ; line exports, the parallel dictionaries will provide for documentation of derivation, morpho-syntactic information on valency and government, seman- tics and etymology.Peer reviewe

Electrophoretic separation of human kidney cells at zero gravity

Electrophoretic isolation of cells results in a loss of resolution power caused by the sedimentation of the cells in the media. The results of an experiment to extract urokinase from human embryos during the Apollo Soyuz mission are presented and discussed

Psychological tools for knowledge acquisition

Knowledge acquisition is said to be the biggest bottleneck in the development of expert systems. The problem is getting the knowledge out of the expert's head and into a computer. In cognitive psychology, characterizing metal structures and why experts are good at what they do is an important research area. Is there some way that the tools that psychologists have developed to uncover mental structure can be used to benefit knowledge engineers? We think that the way to find out is to browse through the psychologist's toolbox to see what there is in it that might be of use to knowledge engineers. Expert system developers have relied on two standard methods for extracting knowledge from the expert: (1) the knowledge engineer engages in an intense bout of interviews with the expert or experts, or (2) the knowledge engineer becomes an expert himself, relying on introspection to uncover the basis of his own expertise. Unfortunately, these techniques have the difficulty that often the expert himself isn't consciously aware of the basis of his expertise. If the expert himself isn't conscious of how he solves problems, introspection is useless. Cognitive psychology has faced similar problems for many years and has developed exploratory methods that can be used to discover cognitive structure from simple data

Charm production at HERA

The ZEUS data on the charm structure function F_2^c at small x fit well to a single power of x, corresponding to the exchange of a hard pomeron that is flavour-blind. When combined with the contribution from the exchange of a soft pomeron, the hard pomeron gives a good description of elastic $J/\psi$ photoproduction.Comment: 6 pages, plain tex, with 3 figures embedded using epsf. Typos corrected in equations (10) and (11

The Missing Odderon

In contrast to theoretical expectations, experimental results at sqrt(s)=200 GeV for the reaction gamma p --> pi0 X show no evidence for odderon exchange. The upper limit on the cross section is an order of magnitude smaller than the theoretical estimate. It is argued that chiral symmetry leads to a large suppression, taking the thoeretical estimates well below the data. Two additional arguments are presented which may decrease the theoretical estimate further. The calculations are more sensitive to the assumptions made in evaluating the hadronic scattering amplitude than in the processes considered previously and lattice gauge calculations indicate that the odderon intercept may be appreciably lower than usually assumed. These two latter effects are particularly relevant for the reactions gamma p --> f2(1270)X and gamma p --> a2(1320)X for which the data upper limits are also below the theoretical predictions, but not so dramatically as for gamma p --> pi0 X.Comment: 12 pages, 3 figure