New type of asymmetric fission in proton-rich nuclei.

A very exotic process of ß-delayed fission of 180Tl is studied in detail by using resonant laser ionization with subsequent mass separation at ISOLDE (CERN). In contrast to common expectations, the fission-fragment mass distribution of the post-ß-decay daughter nucleus 180Hg (N/Z=1.25) is asymmetric. This asymmetry is more surprising since a mass-symmetric split of this extremely neutron-deficient nucleus would lead to two 90Zr fragments, with magic N=50 and semimagic Z=40. This is a new type of asymmetric fission, not caused by large shell effects related to fragment magic proton and neutron numbers, as observed in the actinide region. The newly measured branching ratio for ß-delayed fission of 180Tl is 3.6(7) × 10(-3)%, approximately 2 orders of magnitude larger than in an earlier study.

[Mass occurrence of mycotic tracheitis in chickens]. / Hromadný výskyt mykotické tracheitidy kurat.

An enzootic of chick mycosis, caused by the spores of the fungus Aspergillus fumigatus, is described. The mycotic infection affected the respiratory tract of the birds; pathological changes were located mainly in the region of the trachea. The changes had the nature of diphtheroid necrotic inflammation destroying the mucous membrane and causing almost an obstruction of the trachea. Deposits of granulomatous inflammation, containing fungus elements, were detected in the peritracheal tissue, and in individual birds also in the lungs. Litter contaminated with Aspergillus was the source of infection.

[Disseminated aspergillosis in a loon]. / Diseminovaná aspergilóza potáplice.

A case is described of generalized mycosis in a diver of the species Gavia arctica, caused by the fungus Aspergillus fumigatus. The organism of the bird was so much damaged that the bird died. There is a detailed description of the mycological characteristics of the invading agent and a description of the histopathological changes in the primarily affected organ -- the lungs. Further, a survey is presented of the orders of freely living birds and birds in captivity in which aspergillosis has been detected.

Order of precedence and age of Y-DNA haplotypes.

A simple method, inspired by procedures used in the physics of nuclear multi-fragmentation, allows for establishing order of precedence and age of pairs of haplotypes separated by one mutation. For both haplotypes of the pair, searches for existing haplotypes, differing by increasing number of mutations, are carried out using a database. The resulting ratios of frequencies of haplotypes, found at given mutation distances, are compared to calculated probability ratios. The order of precedence and age of the pair of haplotypes can be deduced when the resulting ratios follow a hyperbolic dependence. The method can be used with relatively small and not necessarily complete samples, using publicly accessible databases.

Enhanced production of neutron-rich rare isotopes in peripheral collisions at Fermi energies.

A large enhancement in the production of neutron-rich projectile residues is observed in the reactions of a 25 MeV/nucleon 86Kr beam with the neutron-rich 124Sn and 64Ni targets relative to the predictions of the EPAX parametrization of high-energy fragmentation, as well as relative to the reaction with the less neutron-rich 112Sn target. A hybrid model based on a deep-inelastic transfer (DIT) code followed by a statistical deexcitation code accounts for part of the observed large cross sections. The DIT simulation indicates that the production of neutron-rich nuclides in these reactions is associated with peripheral nucleon exchange in which the neutron skins of the neutron-rich 124Sn and 64Ni target nuclei may play an important role. From a practical viewpoint, such reactions offer a novel synthetic avenue to access extremely neutron-rich rare isotopes towards the neutron-drip line.