Table of contents

Current theoretical and experimental approaches to the pion–pion interaction are discussed and the results obtained are presented. Experiments on πN → ππN reactions as a source of information on ππ scattering are described as well as polarized target experiments and those on K_e4 decay and pionium. The concepts of effective field theory and the basic ideas of chiral perturbation theory are discussed. The problem of light scalar resonances is analyzed and the incorrectness of data analysis procedures is considered.

The state of the art of electron transport in the extreme quantum limit in magnetic field, when only the lowest Landau subband with one spin orientation is filled, is reviewed for the ionized-impurity scattering case, the one of most experimental interest. The quasi-one-dimensionality of electron motion is taken into account. This results in an essential modification of the conduction processes both along and perpendicular to the magnetic field, in contrast to what was supposed earlier. A reasonably good agreement is obtained with experimental data.

A review is presented of the experimental work on the influence of quantum fluctuations on the magnetization and the mean spin of magnetic sublattices in quasi-one-dimensional triangular antiferromagnets. The principal results in this area are the strong magnetic-field dependence of magnetic sublattice mean spins; anisotropy of mean spin values in magnetically nonequivalent antiferromagnetic chains; the reduction of magnetization compared to the classical spin case; the nonlinear growth of the parallel magnetic susceptibility; a residual magnetization anisotropy at high fields. The results obtained are explained based on the spin-wave theory of quantum fluctuations in antiferromagnets. A new magnetic phase was observed in CsMnI₃ for HC₆ and shown to be due to the anisotropy of the mean spins of the sublattices.

The logical fundamentals of the theory of climate are outlined: (1) the climate system OLA (ocean–land–atmosphere) is defined; (2) analogously to the theory of turbulence, the notion of climate is defined as a multicomponent random function in the OLA space-time (or, equivalently, as a statistical ensemble of states the OLA system passes through in a period of several decades); (3) the solar climate, i.e. the distribution of solar radiation at the upper atmosphere boundary, is determined, to be employed as the boundary condition for the OLA system; (4) the 'horizontal' heat and mass transfer processes between the equatorial and polar zones are described; (5) the 'vertical' processes of radiative–convective heat and mass transfer, among them the greenhouse effect of water vapor and small gas admixtures, are discussed; (6) the 'vertical' radiative heat transfer processes in an aerosol-containing atmosphere is considered, including the anti-greenhouse effect of volcanic and smoke aerosols, and the 'nuclear night' and 'nuclear winter' scenarios.

The temperature dependence of the residual and spontaneous magnetization in ferrites with a 'weak' sublattice may be taken as evidence for the pyromagnetic effect — a magnetic analog of the pyroelectric effect — in which the magnetization of a sample increases on cooling in the absence of an external magnetic field. A confirmation of this has been provided by the observation of a thermodynamically inverse phenomenon, the linear magnetocaloric effect, in such ferrites. These effects are due to the unidirectional exchange anisotropy characteristic of ferrimagnets with a weak sublattice.