Variational problems in the theory of hydroelastic waves.

This paper outlines a mathematical approach to steady periodic waves which propagate with constant velocity and without change of form on the surface of a three-dimensional expanse of fluid which is at rest at infinite depth and moving irrotationally under gravity, bounded above by a frictionless elastic sheet. The elastic sheet is supposed to have gravitational potential energy, bending energy proportional to the square integral of its mean curvature (its Willmore functional), and stretching energy determined by the position of its particles relative to a reference configuration. The equations and boundary conditions governing the wave shape are derived by formulating the problem, in the language of geometry of surfaces, as one for critical points of a natural Lagrangian, and a proof of the existence of solutions is sketched.

[Treatment of unstable fractures of distal metaepiphysis of radial bone in elderly patients].

Features of supraosteal osteosynthesis of the distal metaepiphysis of radial bone in elderly patients, permitting stable fixation of bone fragments in conditions of osteoporosis, were highlighted. Results of treatment of 35 patients, aged 60-78 years were analyzed. The proper plate positioning and conduction of the distal screw line provides the stable fixation, eases early rehabilitation and facilitates good functional results.

Modelling nonlinear hydroelastic waves.

This paper uses the special Cosserat theory of hyperelastic shells satisfying Kirchoff's hypothesis and irrotational flow theory to model the interaction between a heavy thin elastic sheet and an infinite ocean beneath it. From a general discussion of three-dimensional motions, involving an Eulerian description of the flow and a Lagrangian description of the elastic sheet, a special case of two-dimensional travelling waves with two wave speed parameters, one for the sheet and another for the fluid, is developed only in terms of Eulerian coordinates.