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We explore variational Poisson–Nijenhuis structures on nonlinear PDEs and establish relations between Schouten and Nijenhuis brackets on the initial equation with the Lie bracket of symmetries on its natural extensions (coverings). This approach allows to construct a framework for the theory of nonlocal structures.
The rate of testicular degeneration and the drop in plasma testosterone levels were compared in what were referred to as short-term domesticated (STD) and long-term domesticated (LTD) Syrian hamsters when they were maintained under short photoperiodic conditions (light:dark cycles of 10:14). STD hamsters were derived from wild stock captured in 1971; LTD… (More)
This report contains three separate papers, each addressing selected issues concerning natural gas policy and security of gas supply in Europe. The over-arching themes are vulnerability (to supply disruptions, to supplier pricing power) and fragmentation; and measures designed to overcome them, namely interconnection and consolidation of bargaining power.… (More)