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The radiative decays of resonances with Λ o hyperons involved have been studied in the 24-liter propane bubble chamber exposed to 4.0 GeV/ c negative pions. The M Λγ effective mass distribution exhibits a peak which can be explained by the existence of the Λη o -resonance with mass of about 1680 MeV. The kinematic influence of the known hyperon resonances on the distributions is discussed. An attempt is being made to determine the Λη o -spin.

By the microbiological assay, utilizing Lactobacillus leichmannii as a test organism, variations of the vitamin B12 contents of various tissues in the course of development of chick embryo and the human fetus are observed. A comparison between the vitamin B12 contents in various tissues of pregnant rabbits are also made. (1)The vitamin B12 contents in liver, heart and lung of the chick embryo increased progressively from 12 days' incubation as the embryonic development proceeds

The neutron resonance parameters for niobium and rubidium in the energy range up to 400 eV and up to 1300 eV, respectively were determined by measuring the transmission, capture, scattering and self-indication. The obtained values of the radiation widths for niobium s and p wave levels coincide within the measurement error. The radiation width for the magic nucleus of Rb 87 is less than that for the nonmagic Rb 85 . The experimental data on the radiation widths of medium nuclei show a minimum in the region of the closed shell with the number of neutrons equal to 50.