The measurements of partial production cross-sections of the multiple helium fragments emitted at 14.6 A GeV 28Si–emulsion interactions are reported. The production rate of helium fragments due to fragmentation of 28Si ions is studied and compared with that obtained from different projectiles at various energies. The dependence of ⟨Nα⟩ on the mass number of the incident beams is formulated. The multiplicity distributions of the helium fragments produced in 14.6 A GeV and 3.7 A GeV 28Si aswell as 200 A GeV 32S exhibit KNO scaling. The characteristics of He-multiplicity events associated with and without projectile fragments of charge Z ⩾ 3 are investigated.

A survey on mites associated with stored seeds, flour and foodstuffs in Fayoum Governorate, Upper Egypt, proved the occurrence of about 24 species. Of these, 15 species in 8 families belong to Prostigmata, 6 species in 3 families belong to Astigmata and 3 species in 2 families belong to Mesostigmata. Members of the families Cheyletidae and Acaridae were the most common mites, found in many samples. Those of Caligonellidae, Ascidae and Raphignathidae were fairly common, but occurred in fewer types of samples. No mites were found in samples of lupine and camomile.

Central collisions of and 28Si nuclei with heavy (AgBr) nuclei in nuclear emulsion at 4.5GeV/c per nucleon are selected and investigated under several selecting criteria. Central cross sections and average number of interacting protons from both projectile and target nuclei, multiplicity distributions of shower particles and dispersions are discussed in the framework of the Glauber model. The multiplicities of produced charged secondaries are studied according to the nucleon-nucleus superposition model. The multiplicity distributions and mean values of grey particles are also investigated via a parameter free model whose input information is the distribution of grey particles produced in proton induced reactions. It is shown that the selection criterion of central collisions based only on the small total charge of stripping particles is too weak. The selection criteria based on the high multiplicity of total secondary charged particles, the high degree of target destruction and the large number of interacting protons augmented by the small total charge of stripping particles provide satisfactory agreement with the theoretical calculations.

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