The risk through chemical exposure is commonly characterized by ratios of exposure concentrations and effect levels (risk quotients). For chemicals with many different applications such as solvents, however, in addition to the risk quotients of different exposure situations it is useful to determine the corresponding numbers of exposed individuals, that is, not only the magnitude but also the extent of the risk. To this end, the Scenario‐Based Risk Assessment (SceBRA) method has been developed that makes use of a large set of scenarios, each of which describes a typical situation regarding handling a solvent or solvent‐containing product. The scenarios cover the life‐cycle steps of production, distribution, and use of solvents. For each scenario, SceBRA provides the risk quotient, r, and the number of exposed individuals, N. This study investigated seven solvents that are used in large amounts in Switzerland. For each solvent, characteristic distributions of r and N values were calculated, making it possible to compare different solvents with respect to their risk profile. Graphical representations of the r, N data provide an informative way for analyzing and communicating the results of SceBRA.

The article summarizes the plans and expectations of the B meson experiments BABAR, BELLE, CDF, CLEO, D0, and HERA-B for the next few years. Special emphasis is put on the determination of CKM matrix parameters and on CP violation.

Three experiments were carried out to investigate the effect of 0-5000 IE vitamin A/kg semisynthetic diet in 2100 hy brids of chicks. The experiments lasted 20, 6 and 4 weeks, respectively.The vitamin A supply did not influence the rearing performance during the first two weeks after hatching. At the third week of life food intake and life weight gain were reduced in laying hens without vitamin A supplementation. Their feed efficiency was impaired. As a rule there were no significant differences between the groups with 750-5000 IE vitamin A supply regarding the obtained parameters. Furthermore, the vitamin A concentration in feed correlated with the vitamin A content of the liver and plasma, but there was a negative correlation with the vitamin E content of the liver. Further parameters like various enzymes, triglycerides, hormon of the thyroidea, the immune response to human's gammaglobuline and RBC's of sheep in blood plasma and the blood picture were also obtained.750 IE vitamin A/kg diet are essential to avoid clinical deficiency symptomes in chicken and young laying hens. They request 1500 IE and 500 IE vitamin A/kg diet, respectively for an optimal life weight gain. 3000 IE vitamin A/kg diet are good for a sufficient vitamin A storage in the liver and an immune response to RBC's of sheep. It os recommened, that including a safty amount the mixed diet of chicken and young laying hens should contain 4000 IE and 2000 IE vitamin A/kg diet, respectively.

The reaction of [(cod)IrCl]2 (cod = eta4-cycloocta-1,5-diene) with n-C3H7Li gives non-isolable (cod)IrH species by beta-elimination of (cod)Ir-n-C3H7 intermediates; the stable final products of further reactions with RC = CR highly depend on the nature of the substituents R. With R = Me the 6-endo-H-hexamethylcyclohexadienyl complex 1 is obtained together with the iridacyclopentadienyl compound 2 and known {[(cod)IrH]4C3H4} (3). In case of R = Et steric effects cause transfer of the hydridic hydrogen to the cod ligand, the hexaethylbenzene species 4 is isolated which was characterized by crystal structure analysis. The reaction system with tolane again yields a 6-endo-H-cyclohexadienyl complex (5). In all cases free substituted benzenes are formed as cyclotrimerization products of the alkynes.

The reaction of [(cod)IrCl] 2 (cod=η 4 -cycloocta-1,5-diene) with n-C 3 H 7 Li gives non-isolable (cod)IrH species by β-elimination of (cod)Ir-n-C 3 H 7 intermediates; the stable final products of further reactions with RC≡CR highly depend on the nature of the substituents R. With R=Me the 6-endo-H-hexamethylcyclohexadienyl complex 1 is obtained together with the iridacyclopentadienyl compound 2 and known ([(cod)IrH] 4 C 3 H 4 )

The number of chlorine-impaired E. coli organisms obtainable with the aid of the membrane-filtration-Endo-agar-method is so reduced that this method cannot be considered equivalent to liquid enrichment. Notwithstanding the well documented difficulties that arise from differences between batches of the same filters e. g. from problems to assure their standardization, the main obstacles do not stem from the questionable suitability of membrane filters but from the toxicity of the Endo-agar. The use of lactose-pepton (L.P.)-broth (German Standard Methods 1971) equally does not lead to satisfactory results if compared to the use of casein-soya (C.S.)-broth.

We describe the two gamma detectors built for the European Hybrid Spectrometer (EHS). Their monitoring system is presented in detail. Results from tests and the performance obtained during the first EHS experiment are given.