[en] Looking back at the three previous meetings (Lyon 1976, Lausanne 1980, Berlin 1984) it is clear that the field of clusters has gained in certainty, in depth and in width, but keeping generally along the initial lines already sketched more than 10 years ago. I see progresses on three fronts. (orig.)

[en] A brief survey of results of studies of nuclear chirality in the mass 80 and 190 region at iThemba LABS is given, before looking at the case of "1"0"6Ag in detail. Here, the crossing of a pair of candidate chiral bands is re-interpreted as the crossing of a prolate band by an aligned four-quasiparticle band. (author)

[en] Short communication

[en] The status of theoretical and experimental studies of the nature of residual nuclear interactions and their effect on nuclear excited states in actinide elements is reported. Information obtained concerning nuclear-atomic interactions is discussed. In addition, investigations of alpha and electron capture decay, core emission in beta decay, and beta spectrum shapes are described for several heavy elements. A new measurement of the half-life of ²³³U is included. (U.S.)

[en] A perturbative approach is used to obtain small-amplitude solitary structures for an extended nonlinear Schroedinger equation. These structures have the form of dark and anti-dark solitary wave solutions, closely connected with the Korteweg-de Vries solitons. The solutions found are valid in wavelength regions, such as those applicable in the anomalous dispersion regime, which are not accessible by the conventional nonlinear Schroedinger equation. The dynamics of the derived structures in the presence of the Raman effect is also studied by means of a Korteweg-de Vries-Burgers equation. The obtained results are applied to the problem of propagation of femtosecond duration pulses in nonlinear optical fibres. (author)

[en] Within the Landau quasiparticle approach, we analyze the possibility of merging of different single-particle levels in finite spherical Fermi systems. It is demonstrated that the opportunity for this behavior is widespread in quantum many-body systems. The salient feature of the phenomenon is the occurrence of nonintegral quasiparticle occupation numbers, leading to a radical alteration of the standard quasiparticle picture. Implications of this alteration are considered for atomic and solid-state systems

No abstract available

[en] A new phenomenological model describing nonequilibrium superconductivity is proposed which is characterized by the introduction of a quasithermal distribution of phonons with energies of 0--infinity. The model exhibits μ(-model-like and T(-model-like Δ vs n and μ( vs n characteristics when the excess quasiparticle density n is low and high, respectively. The estimated critical density n/sub c/ for the onset of instability is much lower than that of the μ( model. These results are in fairly good agreement with the experimental results reported by Willemsen and Gray, and Akoh and Kajimura

[en] High-spin states of "1"6"0Tm are studied via in-beam gamma-ray spectroscopy. Previously known rotational bands are confirmed. These bands feed into low-lying states which are enriched in this work. A four-quasiparticle band with configuration of πg_7_/_2 ⊗ νh_9_/_2 ⊗ ν(i_1_3_/_2)"2 is established. Signature splitting features of πh_1_1_/_2⊗νi_1_3_/_2 and πh_1_1_/_2⊗νh_9_/_2 bands are presented. (author)

[en] A new quasi-particle basis of states is presented for all the irreducible modules of the M(3,p) models. It is formulated in terms of a combination of Virasoro modes and the modes of the field φ_2,1. This leads to a fermionic expression for particular combinations of irreducible M(3,p) characters, which turns out to be identical with the previously known formula. Quite remarkably, this new quasi-particle basis embodies a sort of embedding, at the level of bases, of the minimal models M(2,2κ+1) into the M(3,4κ+2-δ) ones, with 0=<δ=<3