[en] Short communication

[en] The properties of finite nuclei are investigated in the framework of a chiral field theory using relativistic mean field approximation. It is shown that the normal type solutions for finite nuclei do exist

[en] The ground states of finite nuclei are constructed in the framework of the chiral field theory, using the relativistic self-consistent Hartree approximation. It is shown that, contrary to the traditional view, a normal ground state of finite nuclei exists. Using two adjustable parameters, the Fermi surfaces, charge densities, and rms charge radii of doubly magic nuclei are calculated. 18 refs., 4 figs., 2 tabs

[en] The exact Green's functions (GF) of the periodic Anderson model (PAM) for U→∞ can be formally expressed within the cumulant expansion in terms of an effective cumulant that was approximated in a previous work by the value it takes for the exactly soluble atomic limit of the PAM. Expressions for the magnetic susceptibility χ(T), static conductivity σ(T) and optical conductivity σ(ω,T) of the PAM have been obtained with these approximate GF and they are employed here to fit the experimental values of FeSi, a compound that behaves like a Kondo insulator with the two first quantities vanishing rapidly for T→0. It was possible to find good agreement between theory and experiment for a set of parameters in the intermediate valence region

[en] The relativistic mean field and Hartree-Fock approximations to nuclear-matter and finite nuclei are discussed. The relativistic effects are important in nuclear saturation mechanism and spin-orbit splitting. Connections with the non-relativistic Hartree-Fock-Skyrme formalism are also analysed. (author)

[en] We have investigated the role of the exchange effects in a chiral theory in the framework of the self-consistent Hartree-Fock approximation to nuclear matter and light finite nuclei. The properties of normal solutions are found to be better agreement with the experiment than in the Hartree case. Modification of the properties of abnormal solutions is also discussed

[en] Several thermal properties of finite nuclei are calculated using the energy density formalism and a variational method with trial functions of Fermi type. The change with temperature of the density distribution is studied. The level density parameter is found for small excitation. The influence of the Weizsaecker inhomogeneity correction to the kinetic energy is shown

[en] A realistic mean field approach based on the Walecka theory for nuclear matter is used to derive the optical potential for nucleon and antinucleon-nucleus systems. The total and reaction cross sections are calculated in the WKB approximation for different nuclei ranging from carbon to lead and for incident energies between 0.1 and 2 GeV. (orig.)

[en] The pseudo-spin symmetry (PSS) is investigated in the framework of the relativistic Hartree-Fock approximation (RHFA). The Dirac equation is reduced to a Schroedinger like equation for the small component of the nucleon spinor. Though this equation reveals that the symmetry appears to be broken even in the Σ_S^D+Σ₀^D=0 limit, where Σ_S^D and Σ₀^D are the direct (Hartree) scalar and time component of the vector nucleon self-energies, respectively, pseudo-spin symmetry is approximately conserved. The behavior of the single-particle potentials and of the wave functions of both neutron and proton pseudo-spin doublets in the ⁴⁰Ca and ⁴⁸Ca nuclei are analyzed. There is no dominance of the term dependent on the pseudo-orbital angular momentum (containing the pseudo-centrifugal barrier) compared to the pseudo-spin-orbit potential (PSOP). The contributions to the energy of each pseudo-spin doublet (PSD) level coming from all terms entering the equation for the small component of the Dirac spinor are calculated. The quasi-degeneracy of the PSD levels in the RHFA can be explained by a compensation of the differences between these contributions. The effect of the self-consistency is comparable to that of the PSOP itself

[en] The yellow fever 17D virus is attenuated and used for human vaccination. Two of its substrains, 17D-204 and 17DD, are used for vaccine production. One of the remarkable properties of this vaccine is limited viral replication in the host but with significant dissemination of the viral mass, yielding a robust and long-lived neutralizing antibody response. The vaccine has excellent records of efficacy and safety and is cheap, used as a single dose, and there are well-established production methodology and quality control procedures which include the monkey neurovirulence test (MNTV). The present study aims at a better understanding of YF 17DD virus attenuation and immunogenicity in the MNVT with special emphasis on viremia, seroconversion, clinical and histological lesions scores, and their intrinsic variability across the tests. Several MNVTs were performed using the secondary seed lot virus 17DD 102/84 totaling 49 rhesus monkeys. Viremia was never higher than the accepted limits established in international requirements, and high levels of neutralizing antibodies were observed in all animals. None of the animals showed visceral lesions. We found that the clinical scores for the same virus varied widely across the tests. There was a direct correlation between the clinical scores in animals with clinical signs of encephalitis and a higher degree of central nervous system (CNS) histological lesions, with an increase of lesions in areas of the CNS such as the substantia nigra, nucleus caudatus, intumescentia cervicalis, and intumescentia ventralis. The histological scores were shown to be less prone to individual variations and had a more homogeneous value distribution among the tests. Since 17DD 102/84 seed virus has been used for human vaccine production and immunization for 16 years with the vaccine being safe and efficacious, it demonstrates that the observed variations across the MNVTs do not influence its effect on humans