Mechanism of the historical and the ongoing Vulcanian eruptions of Ebeko volcano, Northern Kuriles.

Ebeko is one of the most active volcanoes of the Kurile island arc, producing frequent mild Vulcanian explosions with eruption clouds up to 5 km high. The volcano poses a serious threat to the Severo-Kurilsk town with a population of around 2500 inhabitants, located at a distance of only 7 km on a fan of the volcano's laharic deposits. Here, we report an overview of the activity of the volcano in the 20th-21st centuries and the results of our geological and petrological investigations of the ongoing Vulcanian eruption that started in 2016. We have found that eruptions of Ebeko span a range of mechanisms from purely magmatic to phreatic/hydrothermal. Three of its historical eruptions (the 1934-1935, 1987-1991, and the 2016-ongoing) involved fresh magma, while during the others (1967-1971, 2009-2011) fresh magma was not erupted. Juvenile material of the ongoing eruption represents highly crystalline and highly viscous (more than 108 pa s) low-silica (56-58 wt% SiO2) andesite. Historical data and our observations of the ongoing eruption allowed us to suggest a functional model of the volcano where Vulcanian explosions are caused by shallow intrusions of small diapir-like batches of strongly crystallized and highly viscous andesitic magma ascending into water-saturated, hydrothermally altered rocks composing the volcano summit. We suggest that the diapir's ascent is governed by their positive buoyancy. Some of the diapirs reach and breach the ground surface producing magmatic eruptions of Ebeko, while the others are stuck at the shallow subsurface level and feed intensive hydrothermal activity as well as phreatic eruptions of the volcano. Positive buoyancy of the diapirs is too weak to allow them to extrude high above the ground surface to form lava domes. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00445-020-01426-z.

Geographic variation of life-history traits in the sand lizard, Lacerta agilis: testing Darwin's fecundity-advantage hypothesis.

The fecundity-advantage hypothesis (FAH) explains larger female size relative to male size as a correlated response to fecundity selection. We explored FAH by investigating geographic variation in female reproductive output and its relation to sexual size dimorphism (SSD) in Lacerta agilis, an oviparous lizard occupying a major part of temperate Eurasia. We analysed how sex-specific body size and SSD are associated with two putative indicators of fecundity selection intensity (clutch size and the slope of the clutch size-female size relationship) and with two climatic variables throughout the species range and across two widespread evolutionary lineages. Variation within the lineages provides no support for FAH. In contrast, the divergence between the lineages is in line with FAH: the lineage with consistently female-biased SSD (L. a. agilis) exhibits higher clutch size and steeper fecundity slope than the lineage with an inconsistent and variable SSD (L. a. exigua). L. a. agilis shows lower offspring size (egg mass, hatchling mass) and higher clutch mass relative to female mass than L. a. exigua, that is both possible ways to enhance offspring number are exerted. As the SSD difference is due to male size (smaller males in L. a. agilis), fecundity selection favouring larger females, together with viability selection for smaller size in both sexes, would explain the female-biased SSD and reproductive characteristics of L. a. agilis. The pattern of intraspecific life-history divergence in L. agilis is strikingly similar to that between oviparous and viviparous populations of a related species Zootoca vivipara. Evolutionary implications of this parallelism are discussed.

[Changes in the lipid composition of the blood serum lipoproteins during the hormonal treatment of patients with bronchial asthma]. / Izmenenie lipidnogo sostava lipoproteidov syvorotki krovi v protsesse lecheniia gormonami bol'nykh bronkhial'noi astmoi.

Ultracentrifugation, thin-layer and gas-liquid chromatography were employed to study changes in lipid metabolism in 25 patients with bacterial asthma on glucocorticoid therapy. Before and 1 weeks after administration of glucocorticoid measurements were made of phospholipids, cholesterol and its esters, triacylglycerols in LDL, HDL2 and HDL3. It was found that hormone treatment leads to an increase in the total phospholipid pool in all lipoprotein fractions. High levels of lecithin and palmitinic acid contributed to improvement in composition of pulmonary surfactant. Decreased atherogenicity, a trend to membrane stabilization were positive, while high percentage of saturated fatty acids and low levels of polyenic acids in LDL and HDL2 were negative effects of hormone treatment. Correction of metabolism at the level of fatty acid composition is necessary.

[Characteristics of the lipid composition of atherogenic and anti-atherogenic serum lipoproteins in patients with bronchial asthma]. / Kharakteristika lipidnogo sostava aterogenykh i antiaterogennykh lipoproteidov syvorotki krovi bol'nykh bronkhial'noi astmoi.

Complete lipid composition was estimated in both atherogenic lipoproteins of low density (LDL) and in antiatherogenic lipoproteins of high density HDL2 and HDL3 subfractions isolated from blood serum of 25 healthy volunteers and of 40 patients with bronchial asthma; ultracentrifugation, thin-layer chromatography and spectrophotometry were used in experiments. Development of bronchial asthma was accompanied by district impairments in the spectrum of structure containing lipids especially due to decrease in content of lecithin in LDL and HDL2, of phosphatidic acid in LDL and in the HDL fractions; both these lipids are main constituents of the surfactant system in the respiratory tract. Besides, metabolism of cholesterol was also impaired, while cholesterol esters were redistributed between various lipoproteins, thus total cholesterol was increased in LDL and HDL3; however, cholesterol coefficient in the patients maintained within the same limits as compared with that of donors.

[Status of the peroxidation-anti-oxidation system in patients with sarcoidosis of the respiratory organs]. / Sostoianie perekisno-antioksidantnoi sistemy u bol'nykh sarkoidozom organov dykhaniia.

Parameters of lipid peroxidation (LPO) and of the antioxidant system (AOS) were analysed according to the level of diene conjugates (DC) and blood serum antiradical activity (ARA), respectively. Study included 115 patients with active respiratory sarcoidosis. The DC level was found to be significantly increased in 89-97% ot the examined patients. At the same time, the ARA changes had a differently directed pattern. The DC/ARA coefficient was estimated which was also increased in most patients providing evidence on the peroxide-antioxidant system imbalance in active sarcoidosis patients. It was found that the parameters were dependent on the process duration. They were studied in dynamics against the background of combined therapy in 2-4-6 months and in the remote periods (1-2 years). Dynamic changes in the biochemical parameters had the unidirectional pattern with manifestation of the clinical and X-ray process dynamics. There was a significant difference in the rate and degree of changes in the LPO-AOS parameters depending on the activity degree of sarcoidosis process and treatment effectiveness. It is believed that the antioxidant therapy is necessary in all sarcoidosis forms at the early stages of treatment and that its duration should be no less than 4 months in the acute process while the protracted course requires a longer period of time.

The study of pathogenetic basis of asthma using biostatistic models.

In 50 patients with asthma we have determined skin tests on dust and pollen allergens, forced expiratory volume for one second (FEV1) before and after subcutaneous injections of epinephrine standard dose, adrenoreactivity by adrenodependent cyclic AMP levels and glycogenolysis, cyclic AMP phosphodiesterase activity, levels of eosinophils in blood (in all 28 characteristic features). Factor and correlation analysis were carried out by electronic computer. In addition, in 121 patients we have determined adrenodependent glycogenolysis in leucocyte suspension incubated with various allergens the content of diene conjugates and total antioxidative activity of plasma. It is concluded that atopic and nonatopic forms of asthma are diseases of different nature in their constitutional origin, pathogenic agents of environment and cellular and subcellular mechanisms of their development. Moreover, the pathogenetic role of allergen-induced lipid peroxidation that correlates with lymphocyte adrenoreactivity is shown.

[New tetraene antibiotic, abkhazomycin]. / Novyi tetraenovyi antibiotik abkhazomitsin

The cultures of Act. L10-0740 and L10-0772 were isolated from a soil sample. By their morphological and cultural features they were close to Act. badiocolor and differed from the latter by their antibiotic properties. Because of this they were classified as a new variant of Act. badiocolor var. abhasus var. nov. The cultures produced a new tetraen antibiotic, named abkhazomycin. Its physico-chemical properties are presented.