[en] This paper discusses the unusual nuclear features of nuclei in the A = 100 region resulting from subshell effects. Two of these features are a rapid onset of deformation at N = 60 and the existence of an almost doubly-magic nucleus of ⁹⁶Zr characterized by an almost complete closure of the d/sub 5/2/ neutron and p/sub 1/2/ proton orbits. 9 refs., 1 fig

[en] Spin assignment to nuclear levels can be obtained from standard in-beam gamma-ray spectroscopy techniques and in the case of compound nuclear reactions can be complemented by statistical methods. These are based on a correlation pattern between level spin and gamma-ray intensities feeding low-lying levels. Three types of intensity and level spin correlations are found suitable for spin assignment: shapes of the excitation functions, ratio of intensity at two beam energies or populated in two different reactions, and feeding distributions. Various empirical attempts are examined and the range of applicability of these methods as well as the limitations associated with them are given. 12 references

[en] The low-spin β-decay of /sup 96,98/Y has been reinvestigated to obtain detailed informatin on the fast first-forbidden transitions to the ground states of /sup 96,98/Zr. A considerably more detailed decay scheme of ⁹⁶Y confirms the general features of a previous study. The spin of the ground state of ⁹⁸Y has been measured to be 0/sup /minus// from γγ(Θ) angular correlations in ⁹⁸Sr → ⁹⁸Zr decay and from Q/sub β/ measurements by β--γ coincidences in the decay of ⁹⁸Y → ⁹⁸Zr. From β-decay data on ^90-100Y nuclei, mixing of the ''spherical'' and ''collective'' 0/plus/ states is deduced, and the strength of the mixing matrix elements is found to vary greatly across the Zr nuclei. 20 refs., 1 fig., 1 tab

[en] Subshell effects in the A∼100 nuclei are studied. (M.F.W.)

[en] The author presented, on the basis of literature and her own research, contemporary views on the frequency of occurrence of congenital, hereditary and sporadic forms of retinoblastoma and its genetic conditioning. She discussed the results of research on mutation of the gene and chromosomal changes in patients with retinoblastoma, as well as the significance of estimation of esterase D, and the principles of inheriting of the disease. The author then presented data of the first symptoms of the disease, the most important diagnostic methods (computed tomography, USG), the appearance of various clinical forms of retinoblastoma and differential diagnosis. She also discussed contemporary methods and results of treatment of unilateral and bilateral retinoblastoma (radiotherapy, surgery, kriotherapy). (author)

[en] Statistical methods of spin assignment have been tested on the ⁹⁶Tc nucleus populated in the (α, n) reaction. Simple model calculations reproduce two intensity-spin correlations and confirm that the energy corresponding to the maximum in the excitation function and the ratio of gamma-ray intensities obtained at two beam energies both show smooth and strong spin dependence. These correlations are found to be marginally influenced by the yrast and non-yrast character of the levels and are not influenced by level-excitation energy. Contribution from pre-equilibrium reactions and competition between neutron and gamma decay channels may be responsible for minor discrepancies between the calculated and experimental excitation functions

[en] Absolute gamma intensities have been measured for the strong transitions in the decay chain ⁹⁸Rb→ ⁹⁸Sr→ ⁹⁸Y→ ⁹⁸Zr and ⁹⁸Nb→ ⁹⁸Mo and found approximately four times higher than those currently adopted. As a consequence, several contradictions in this crucial chain of nuclei are resolved. Shape coexistence is established in /sup 98/Y with a J/sup π/ = 1^- ''spherical'' ground state and with a previously reported deformed band with band head at 495.7 keV

[en] The N_pN_n systematics is re-examined. Inclusion of a subshell gap at Z=76 removes differences in the N_pN_n systematics in the 132≤A≤208 region. This indicates that once a counting scheme is adopted, which fully accounts for the subshell effects, the resultant systematics of the collective observables is insensitive to the nature of the individual valence orbits and depends only on the quadrupole part of the 'averaged' interaction. A double shell effect at Z=64 and 76 is proposed and explained as stemming from the Federman and Pittel interpretation of the deformation process in this region. (orig.)

No abstract available

[en] A summary of recent experimental efforts on nuclei in very close vicinity to the doubly magic ¹³²Sn and perspectives for further progress in the very near future, are presented. A special attention is given to the selected key developments in this mass region via three avenues of production and investigation of exotic nuclei: β decay at the ISOL facilities, prompt γ-rays in spontaneous fission probed using large Ge arrays, and μ-second isomers produced in the fragmentation and in-flight separation of energetic uranium beams or in fission using recoil separators. (author)