Cyclic and linear trajectories of ecosystem evolution on sand dunes in Siberian taiga: A comprehensive analysis.

Extensive unforested sandy areas on the margins of floodplains and riverbeds, formed by dunes, barchans, and accumulation berms, are a ubiquitous feature across northern Eurasia and Alaska. These dynamic landscapes, which bear witness to the complex Holocene and modern climatic fluctuations, provide a unique opportunity to study ecosystem evolution. Within this heterogeneous assemblage, active dunes, characterized by their very sparse plant communities, contrast sharply with the surrounding taiga (boreal) forests common for the stabilized dunes.

Dealing with sand in the Arctic city of Nadym.

Sand plays an important role in the Arctic urban development as construction material and stable ground. Significance of its studies increases in face of permafrost degradation and coastal erosion and for understanding human capacities to restore natural landscapes after anthropogenic disturbances. This paper examines changing human interactions with sand in the city of Nadym, northwest of Siberia.

[Technique of endarterectomy from pulmonary artery in chronic thromboembolic pulmonary hypertension].

The article gives detailed description of a technique of pulmonary endarterectomy in chronic thromboembolic pulmonary hypertension. The method is based on the experience of the world leader in surgical treatment of this disease--the clinic of California, San Diego headed by Stuart Jamieson, cardiothoracal clinic Papworth Hospital in the only center in Great Britain, where PE is performed and on the experience obtained by the collective of the Department of hospital surgery of the medical department of the St. Petersburg state University and the City multi-field hospital.