[en] This paper summarizes the results of research carried out over the last few years at the Cyclotron Research Center, Liege University, towards the development of a krypton 81m generator for clinical use. This study has presented many aspects: its primary concern is optimum production conditions using a compact cyclotron to produce a generator compatible with routine production as well as the supply reliability necessary for clinical experimentation. This resulted in setting up a completely automatic, microprocessor run production station. It defines the most efficient working conditions, and consequently exploitation conditions, due to the knowledge of the daughter element's extraction mechanisms in gas and liquid phases. It proposes different methods to evaluate the generator's fundamental characteristics and to standardize its different clinical uses. The qualitative and quantitative evaluation of all radionuclide species produced simultaneously to the ⁸¹Rb precursor constitutes a new advance in radiopharmaceutical quality control. The problem of sup(81m) Kr dosimetry admistered in liquid or gas phase has been reviewed on the basis of reproducible, optimised experimental results from the latest literature

[en] A direct-channel scheme based on the statistical bootstrap, supplemented by an empirical rule for charges, is applied to NN annihilation into pions. For annihilation at rest, the selection rules due to the predominance of capture from S-orbitals are taken into account essentially through G-parity conservation. The magnitude of the phenomenological channels and the shape of the inclusive momentum distribution are reasonably reproduced. For annihilation at low momenta, use is made of a simple scattering model to set up the scale of the multipion cross-sections leading to a good overall fit. The pattern of charge and multiplicity distributions are well matched, up to rholab=5.7GeV/c. The approach is briefly compared to parallel attempts and appears to yield the best semi-empirical fit to the data. The dominance of crossed-channel exchanges at high energy level restricts the model to the low-energy region. (author)

[en] In the gulf of Calvi, Corsica, three main plant carbon pools are entering the constitution of detrital organic matter : Phytoplankton, Posidonia meadows and benthic macroalgae. By the use of ¹³C/¹²C ratio analyses performed on various plants and animals, it was tried to determine the relative shares of these three pools in the detrital matter ingested by particles feeders. It appears that Posidonia, notwithstanding their important biomass, are a minor food source for zoobenthos. (Author)