Stabilization of beam instability by a local instability developing due to a wave-wave interaction

A new mechanism for stabilization and suppression of beam instabilities is proposed. This mechanism, which is based on the stochastic instability of a wave-wave interaction process, plays a particularly important role in plasma systems with a small region of interaction between the beam particles and the excited waves.     

Quantitative patterns of the thermal inactivation of microorganisms as a basis for obtaining high-quality vaccinal preparations

The model of the thermal inactivation of microorganisms is presented. This model permits the explanation of all existing kinetic dependencies relating to the death of microorganisms, the restoration of sublethal damages, the influence of the medium and the temperature of incubation on the process of the production and control of vaccinal preparations.     

Video registration as a method for studying kinetic parameters of chlorophyll fluorescence in Ficus benjamina leaves

A method of imaging and analysis of fluorescence kinetic parameters distributed over leaf area is described in details. Video data recorded by the CCD-camera were processed using free programs VirtualDub and ImageJ. The method allows not only to image the distribution of fluorescence decrease ratio (Rfd), but also to obtain fluorescence induction curves, which are corresponded to any region of interest selected within the leaf image. A considerable mosaicism of shade leaves of Ficus benjamina L. was shown on the basis of Rfd values, whose functional significance is discussed from the point of view of adaptation to different light intensities. A pronounced non-uniformity of F. benjamina leaves was revealed in relation to the retention time of the secondary fluorescence maximum (peak M). A method of differential imaging was proposed to allow visualization of this non-uniformity and to demonstrate the existence of the previously unknown phenomenon of secondary chlorophyll fluorescence “wave” in leaves. It was also shown the absence of M peak in the chlorophyll-deficient, lacking the mesophyll leaf sectors, where the residual chlorophyll is originated from guard cell chloroplasts.     

Testate amoebae record from the Laptev Sea coast and its implication for the reconstruction of Late Pleistocene and Holocene environments in the Arctic Siberia

Our study aims to look for testate amobae (TA) in the surface and fossil sediments from the Cape Mamontov Klyk (73°60′–73°63′ N, 116°88′–117°18′ E), southern coast of the Laptev Sea, ca 150 km west of the Lena Delta and to discuss the potential of TA analysis for Glacial/Interglacial environmental reconstructions in Arctic Siberia. The radiocarbon age determination suggests that the studied sediments accumulated between ca 45,000 ¹⁴C yr BP and present. A total of 98 TA taxa were identified in the 10 recent surface and 59 fossil samples. Results of taxonomical identification and ecological analysis of TA in the modern and fossil samples suggest that major changes in the soil moisture conditions took place. Our results show that soil-living taxa dominated the TA assemblages at the study sites during the past 45,000 years. The environmental conditions of the study area were most favourable (relatively warm and humid) during the Kargin Interstadial (ca 45,000–25,000 ¹⁴C yr BP). An opposite situation is reconstructed for the Sartan Stadial (ca. 25,000–15,000 ¹⁴C yr BP). During the Kargin Interstadial, optimum conditions occurred between ca 44,000 and 40,000 ¹⁴C yr BP characterised by highest TA abundances and taxa diversity. This initial optimal phase was followed by the interval with drier and colder conditions about 40,000–30,000 ¹⁴C yr BP. The sediments dated between ca. 24,000 and 18,000 ¹⁴C yr BP show low TA abundances and diversity, in agreement with the much colder and drier environments during the maximum phase of the Last Glacial. The onset of the Holocene is indicated by a broad representation of obligate hydrophilic taxa, especially from genus Difflugia, suggesting wet and relatively warm conditions. By comparison with other environmental proxies used in the studied sections as well as from the neighbouring arctic regions our results suggest that TA analysis can provide valuable information, contributing to the better understanding of the Late Quaternary climate and environments in Arctic Siberia.