Conservation and Evolution of Marine and Coastal Ecosystems: Polar Factor

The paper presents an analysis of polar ecological policy actors. From this perspective, authors discuss in detail a role of state in conservation and development of marine and coastal ecosystems. Furthermore, they describe a green agenda for polar regions. At last, some ways for creating of ecological policies in the Arctic and the Antarctic regions, most especially on behalf of sea and marginal ecosystems conservation and evolution, are proposed. One of the most vital parts of such policies is staff training. The authors have attempted a comprehensive analysis of the Green Agenda at the global, national and local levels in terms of the effectiveness of its proposed mechanisms for the protection of biodiversity in polar areas. Researchers have also reviewed plans of Russia according to the new set of strategies for Arctic and Antarctic regions, which were adopted in 2020. The ideas proposed by the authors can be used in a real-case scenario both for strategies implementation and for public discussion on the global ecological problems.

New perturbation bounds in unitarily invariant norms for subunitary polar factors

Let $A\in\mathbb{C}^{m \times n}$ have generalized polar decomposition $A = QH$ with $Q$ subunitary and $H$ positive semidefinite. Absolute and relative perturbation bounds are derived for the subunitary polar factor $Q$ in unitarily invariant norms and in $Q$-norms, that extend and improve existing bounds.