[Osteometric features of duodenal ulcer disease in children depending on the clinical course of the illness].

In order to study the state of the bone tissue in children with duodenal ulcer, we conducted research of peripheral parts of the radius and ulna at the computer osteodensitometer DTX-100 (Denmark) with the help of the quality X-ray absorptiometry method. Osteopenias of various degrees of severity were revealed in 47.22% of patients under study.

Piecewise linear models for the quasiperiodic transition to chaos.

We formulate and study analytically and computationally two families of piecewise linear degree one circle maps. These families offer the rare advantage of being non-trivial but essentially solvable models for the phenomenon of mode locking and the quasiperiodic transition to chaos. For instance, for these families, we obtain complete solutions to several questions still largely unanswered for families of smooth circle maps.

Discrete model of a dynamo with diffusion.

A model of magnetic field generation by the turbulent motions of a highly conducting fluid is constructed. It is assumed that the field is generated in individual cells of space in a statistically independent manner. A coupling between the cells is realized by magnetic diffusion.