The one dimensional Kondo lattice model at partial band filling

The Kondo lattice model introduced in 1977 describes a lattice of localized magnetic moments interacting with a sea of conduction electrons. It is one of the most important canonical models in the study of a class of rare earth compounds, called heavy fermion systems, and as such has been studied intensively by a wide variety of techniques for more than a quarter of a century. This review focuses on the one dimensional case at partial band filling, in which the number of conduction electrons is less than the number of localized moments. The theoretical understanding, based on the bosonized solution, of the conventional Kondo lattice model is presented in great detail. This review divides naturally into two parts, the first relating to the description of the formalism, and the second to its application. After an all-inclusive description of the bosonization technique, the bosonized form of the Kondo lattice hamiltonian is constructed in detail. Next the double-exchange ordering, Kondo singlet formation, the RKKY interaction and spin polaron formation are described comprehensively. An in-depth analysis of the phase diagram follows, with special emphasis on the destruction of the ferromagnetic phase by spin-flip disorder scattering, and of recent numerical results. The results are shown to hold for both antiferromagnetic and ferromagnetic Kondo lattice. The general exposition is pedagogic in tone.Comment: Review, 258 pages, 19 figure

Contribution of different GC-motifs to the control of simian virus 40 late promoter activity.

During the course of lytic infection the 21-bp repeat region regulates differentially the late gene expression; a mutant deleted for this region expresses late genes either to a higher level in the absence of T antigen or to a lower level in the late phase of infection as compared to wild type (23). By analysing a series of clustered point mutations generated within the GC-motifs we show that i) mutations within motifs I and II stimulate late transcription two to three-fold, suggesting that competition for transcription machinery between early-early and late promoters is mediated by these two motifs, ii) after viral replication, simultaneous mutations within motifs IV, V and VI decrease to 23% the efficiency of late transcription, indicating that these motifs are elements of the late promoter. Moreover comparison of results presented in this paper with results published by Barrera-Saldana et al. strongly suggest that late-early and late promoters are regulated in a similar manner