Robust stability in the problem of motion of an inverted pendulum with a vibrating suspension point

The physicochemical and sorption properties of such wastes of the agro-industrial complex of Turkmenistan as seed husks, tumbleweeds and cotton bolls have been studied as a potential raw material for the production of oil sorbents

Dynamics of production parameters for zooplankton as the main component of forage base for nekton in the western Bering Sea

Production parameters of zooplankton are calculated and analyzed on the data of plankton surveys in the framework of BASIS-1 and BASIS-2 research projects conducted in the western Bering Sea in 2002-2013. Top-ten species forming the bulk of non-predatory zooplankton production are the copepods Calanus glacialis, Eucalanus bungii, Neocalanus plumchrus, Pseudocalanus minutus, Metridia pacifica, Oithona similis, and Neocalanus cristatus and euphausiids Thysanoessa inermis, Th. raschii , and Th. longipes . The arrowworm Sagitta elegans produces the main part of predatory zooplankton production. Functional characteristics of trophic groups and production of the whole zooplankton community depend on ratio of these mass species. During the surveyed period, the non-predatory zooplankton production was the highest in the northern part of the western Bering Sea (2531-3160 mg/m3yr) and the lowest in its deep-water part (944 mg/m3yr), whereas the predatory zooplankton production was the highest in the deep-water part of the Sea and over the western shelf. The portion of zooplankton production available for grazing by fish is estimated, and the areas with possible problems for planktivorous consumers are determined: all of them are located in the deep-water part of the western Bering Sea

Robust stability in the problem of motion of an inverted pendulum with a vibrating suspension point

The physicochemical and sorption properties of such wastes of the agro-industrial complex of Turkmenistan as seed husks, tumbleweeds and cotton bolls have been studied as a potential raw material for the production of oil sorbents

The Petrophytic Steppes of the Urals: Diversity and Ecological Drivers

The diversity and main compositional patterns of the petrophytic steppes of the Urals were studied. Two questions were considered in detail: (i) How rich is the phytocoenotic diversity of the petrophytic steppes? and (ii) What kind of ecological drivers determine its differentiation? A dataset of 1,025 relevés was compiled,representing communities of different climatic and geological conditions. Using formalized classification (TWINSPAN algorithm), eight vegetation types on the petrophytic steppes were defined. DCA-ordination was used to determine the main ecological drivers (both climatic and edaphic) of plant communities’ diversity. Among them are mean annual temperature and precipitation, aridity, rockiness and local habitat moisture. The interaction of different ecological and geographical factors leads to high levels of floristic and coenotic diversity of vegetation in dry rocky habitats. Keywords: petrophytic steppes, ecological drivers, ordination, Southern Ural

Dynamics of zooplankton production parameters in the north-western Bering Sea in the present period

On the basis of plankton surveys, conducted in the north-western Bering Sea in 2010-2015, the production characteristics of zooplankton were calculated and analyzed. Zooplankton was divided into two trophic groups: predatory (mainly chaetognaths and hyperiids) and non-predatory (copepods and euphausiids) zooplankton. Considerable variations of zooplankton production parameters were observed in autumn period. This is due to the inter-annual dynamics of regional patterns of the size, taxonomic and trophic structure of zooplankton.The sharp decline in the copepod biomass after 2011 and the significant reduction in the biomass of euphausiids in 2013 were characteristic for the considered period in this region. All these features of the dynamics of copepods and euphausiids had an influence on the value of zooplankton production. The highest non-predatory zooplankton production was in 2010-2011 (up to 5081 mg/m3); the lowest, in 2012-2014 (up to 2716 mg/m3). Production of predatory zooplankton was the most significant in 2013 in the waters of the eastern part of the Gulf of Anadyr; it was associated with the presence of Themisto libellula . In general, non-predatory zooplankton in the north-western Bering Sea produced from 14.8 to 53.1 million tons during autumn; predatory zooplankton, from 5.0 to 14.2 million tons