Profiles of the European Working Groups

In addition to the EURO conferences and the European Journal of Operational Research, the third major justification so far for the very existence of EURO as an association is the European Working Groups (EWGs).Based upon the booklet, “Report on the EURO Working Groups”, produced in 1981 by EURO in cooperation with European Institute for Advanced Studies in Management, the present paper comprises profiles of 10 EWGs. To stimulate interest in the existing groups and possible also in the establishment of new groups, the “Charter of the European Working Groups” is provided in extenso in the concluding section.     

Some (γ, π− xn) reactions on197Au at intermediate energies

The yields for some (γ, π ^? xn)-reactions on¹⁹⁷Au have been measured from threshold to 750 MeV by use of the activation method. The experimental mean cross sections are compared to results obtained from other experiments on similar reactions and to cascade-evaporation calculations.     

Tau decays into four pions

We compute branching ratios and invariant mass distributions of the tau decays into four pions. The hadronic matrix elements are obtained by starting from the structure of the hadronic current in the chiral limit and then implementing low-lying resonances in the different channels. Reasonable agreement with experiment is obtained both for the τ → v_τ+(4π) decay rates and the e⁺ e^? → (4π) cross sections. Furthermore we supply an interface to use our matrix elements within the Tauola Monte-Carlo program.     

New isotope227Rn and revised halflives for223Rn and226Rn

Neutron-rich isotopes of radon, produced by spallation reactions in a ThC² target and selected chemically, were mass-separated and used as samples for radiation counting experiments. Assignments of the activities to radon isotopes were confirmed by genetic relationships to the previously known francium daughters. The halflife for the new isotope²²⁷Rn is 23±1 s and that for²²⁶Rn is 7.4±0.1 min. X-rays,γ-rays, and conversion electrons from the²²³Rn activity were measured. The decay patterns ofK X-rays and known gamma transitions in the²²³Fr daughter yield a halflife of 23.2± 0.4 min for²²³Rn, in contrast to the value of 43± 5 min reported earlier. Energies, intensities, and likely multipolarities for the most prominent gamma transitions in the²²³Rn→²²³Fr decay are presented.     

Hyperfine interaction studies on swift O-ions emerging with polarized electrons from ferromagnetic layers into vacuum

A precision plunger set-up was used to determine in time-differential measurements of hyperfine interactions the degree of polarization of 1s- and 2s-electrons in H- and Li-like oxygen ions on their emergence from magnetized Ni- and Gd-layers into vacuum. In addition a time-integral measurement with Fe-layers served to obtain the polarization of 2s-electrons only. For all three ferromagnetic materials the degree of polarization of 2s-electrons is found to be twice as large as for 1s-electrons. The data are discussed in the context of transient magnetic fields and their underlying polarization mechanism.     

Cyclische Phenyl-carbamate des Miotin-Typs und ihre Wirkung auf die Acetylcholinesterase

Cyclic Phenyl Carbamates and Their Action on Acetylcholinesterase Several six-, seven-, and eight-membered cyclic phenyl carbamates of the miotin type have been synthesised and their in vitro potency as inhibitors of acetylcholinesterase determined. The eight-membered rings were found to be the most potent and are comparable with physostigrnin or miotin. It was concluded that, for maximum potency, the orientation of the carbamate group relative to the aromatic plane has to be close to orthogonal.