The Presidential Office and the President As Party Leader

Syftet med studien är att undersöka kommunikationsmönster hos fem biologilärare på gymnasiet och deras elevgrupper med fokus på frågor. Frågeställningarna avser att undersöka i vilken omfattning lärare och elever ställer frågor och vilka typer av frågor som ställs. Studien analyserar vilka ramfaktorer lärare och elever anser påverkar kommunikationsmönster i form av frågor. Kvantitativ och kvalitativ data har samlats in genom observationer i klassrum, intervjuer med lärare och enkätundersökning med eleverna. Kvantitativ data har analyserats med hjälp av en statistisk programvara, SIMCA-P+. Resultatet visade att frågor utgör en stor del av den kommunikation som sker i ett klassrum, vid jämförelse av olika lärare och elevgrupper är det stor skillnad i hur många och vilka typer av frågor som ställs. Kommunikationsmönstret styrs främst av vilken lärare eller elevgrupp som observerats, därefter kommer undervisningens utformning. Elevenkäterna visade att i vilken grad eleverna förstår, undervisningens utformning och klassrumsklimatet är viktiga ramfaktorer för kommunikation i form av frågor

A Bell pair in a generic random matrix environment

Two non-interacting qubits are coupled to an environment. Both coupling and environment are represented by random matrix ensembles. The initial state of the pair is a Bell state, though we also consider arbitrary pure states. Decoherence of the pair is evaluated analytically in terms of purity; Monte Carlo calculations confirm these results and also yield the concurrence of the pair. Entanglement within the pair accelerates decoherence. Numerics display the relation between concurrence and purity known for Werner states, allowing us to give a formula for concurrence decay.Comment: 4 pages, 3 figure

A random matrix approach to decoherence

In order to analyze the effect of chaos or order on the rate of decoherence in a subsystem, we aim to distinguish effects of the two types of dynamics by choosing initial states as random product states from two factor spaces representing two subsystems. We introduce a random matrix model that permits to vary the coupling strength between the subsystems. The case of strong coupling is analyzed in detail, and we find no significant differences except for very low-dimensional spaces.Comment: 11 pages, 5 eps-figure

Correlations between spectra with different symmetry: any chance to be observed?

A standard assumption in quantum chaology is the absence of correlation between spectra pertaining to different symmetries. Doubts were raised about this statement for several reasons, in particular, because in semiclassics spectra of different symmetry are expressed in terms of the same set of periodic orbits. We reexamine this question and find absence of correlation in the universal regime. In the case of continuous symmetry the problem is reduced to parametric correlation, and we expect correlations to be present up to a certain time which is essentially classical but larger than the ballistic time

The NNLO QCD analysis of the CCFR data for xF_3: is there still the room for the twist-4 terms?

The results of the more detailed NNLO QCD analysis of the CCFR data for $xF_3$ SF are presented. The factorization scale uncertainties are analysed. The NNLO results for $alpha_s(M_Z)$ and twist-4 contributions are obtained. Despite the fact that the amplitude of the $x$-shape of the twist-4 factor is consequently decreasing at the NLO and NNLO, our new QCD analysis seems to reveal the remaining twist-4 structure at the NNLO level. The definite N$^3$LO uncertainties are fixed using the [0/2] Pad\'e resummation technique.Comment: LaTeX, 3 pages, 1 figure; to be published in the Proceedings of DIS99 Workshop, Zeuthen, April 19-23; some technical shortcomings are fixed in the file, 2 referencies correcte