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Based on data of measurements in deep ice boreholes, as well as of radar and space geodetic observations in Antarctica and Greenland, a number of new features of the ice mass transport had been revealed. Note that these features do not correspond to the traditional but still hypothetical notions (ideas) of the monotonous and uniform spatial changes in the ice sheet dynamics. Using results of the long-term monitoring of the borehole coordinate axes at the Vostok station (down to 1920 m), east profile Vostok – Vostok 1 – Pionerskaya – Mirny (1409 km, down to the depth of 450 m), and analysis of radar sections, Russian specialists revealed the following: a) the Antarctic ice sheet has stratified changes in speed and a fan-like change in the flow direction along the depth; b) plastic firn layer has individual parameters of dynamics and actually flows down from more monolithic body of the ice sheet (the flow directions differ by 30–80°); c) in some places inside the sheet, the underlying ice masses flow faster than the upper ones. Researchers from the United States and Denmark registered on the radar sections of the lowest third of the ice domes in the central regions of the Antarctica (AGAP) and Greenland (NEEM) some folded structures, which were not typical of ice sheets (vertical amplitude of the folds is about 400 m, inclination of the wings is about 45 degrees or more). The tectonic analysis we have performed allows making a conclusion that a genesis of these ice structures is identical to the diapir folds and to diapirs which are formed at a displacement of lower plastic ice masses by the upper monolithic ones, or to echelon folds of crumpling of lower ice layers at their faster flow along original bed as compared with the overlying ice mass. This makes possible to suggest that a turbulent ice flow can occur in the spacious near-bottom and the most plastic area, and a model of the ice sheet dynamics is considered as extruding of underlying masses by the overlying ones. Specialists of the United States analyzed results of the radar interferometry obtained from satellites of Canada, the US, Europe, and Japan (RADARSAT-1, 2; Envisat ASAR; ERS-1/2; ALOS PALSAR) and determined a velocity of the flow of the day surface of the Antarctic ice sheet. They constructed a map of the 3D-structure of the ice flows and had revealed that the dominating ice diffluence from the central area down to the coastal zone is in a complicated way composed by many local streams. We conducted the morphological analysis and made the conclusion that these flows interact to one another under conditions of the strong differentiation of a surface inclination of the ice flow moving down along the mountain relief of original bedrock, and this process is similar to a merging of glaciers with individual characteristics due to different ice-catchments.

Nucleation of ice crystals in atmosphere is a result of condensation of water vapor on aerosol particle surface and heterogenic crystallization of the overcooled water micro-aggregations on surface irregularities. Crystal habit of ice nucleus and very small crystals (102 nm) corresponds to Gibbs–Wolf theorem and Thomson-Gibbs equation. Consequent growth of nucleated crystal is possible under condition of exceeding of water vapor concentration in atmosphere over the equilibrium vapor concentration over ice crystal. This equilibrium concentration for each crystal facet can be characterized by Clausius–Clapeyron relation with regard to its surface energy. The diagram of atmospheric ice crystals morphology in dependence from absolute and relative vapor supersaturation of atmosphere is developed. It is determined that the relation of height H and diameter D of atmospheric crystals increases at a growth of relative supersaturation, Δci/ci, but increases at a growth of absolute supersaturation, Δci = ci – ca. The alteration of H/D occurs gradually, which explains conditional character of delimitation on types on the base of this index. The field of absolute and relative supersaturation it is possible to subdivide relatively index H/D value in two parts: columnar forms area, where index H/D > 0.89 and lamellar forms area, where H/D < 0.89. Columnar and needle forms it is possible to characterize as low temperature forms, but lamellar, short-columnar and irregular forms – as high temperature forms. The variety of atmospheric crystal forms is subdivided on four basic groups: solid lamellar, solid columnar, dendrite lamellar and hollow columnar.

Based on the study of local volumes of minerals using the classical methods of isotope dilution and thermal ionization mass spectrometry (U–Pb ID TIMS), an isotopic study of pitchblende and galena is carried out at the Natali uranium ore occurrence (Northern Transbaikalia). For the first time, it was shown that the pitchblende mineralization at the ore occurrence has a Late Silurian (422 ± 4 Ma) age. Its formation is related to the Early–Middle Paleozoic collisional tectogenesis in the area of the Tonod uplift, accompanied by increased fluid activity. The Pb isotopic composition analysis in galena associated with pitchblende show that galena is enriched in radiogenic isotopes 206Pb and 207Pb, a source of which was ancient (Precambrian) concentrations of uranium. [ABSTRACT FROM AUTHOR]

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When working with rare plant species, applying morphometric techniques is one of the main ways to obtain a representative data set on plant individuals and the state of particular populations growing in different ecological conditions and experiencing different degrees of anthropogenic load. Zygophyllum pinnatum, an understudied species growing on the territory of the Republic of Bashkortostan, the Orenburg region, and the Republic of Kazakhstan, is referred as a rare species. The purpose of the work is to study morphometric parameters and reveal the vitality structure of the Z. pinnatum coenopopulations in two regions of the Russian Federation (the Republic of Bashkortostan and Orenburg region) and in the north-west of the Republic of Kazakhstan (the Aktobe Region). Applying standard morphometric techniques, we analyzed the state of 16 coenopopulations of the species. Judging by most morphometric parameters, the leadership belongs to the individuals from the "Troitsk Cretaceous Mountains" coenopopulation located in the Sol-Iletsky District of Orenburg oblast, where, apparently, the most optimal plant conditions are formed (the absence of human impact and low projective cover of the grass stand to have a favorable effect). The minimum values for most parameters are recorded in the coenopopulations located on the territory of the Republic of Kazakhstan, resulting from arid growing conditions. The variability of most characters is within the normal range of the species response (Cv--5.0-44.6%). The discriminant function analysis revealed the morphostructural similarity of individuals from most coenopopulations. Regarding vitality, eight coenopopulations are prosperous, and another eight are depressed. The condition of the species coenopopulations is stable; however, the species is not provided with proper protection measures. Therefore, further monitoring of its habitats and improvement of environmental measures are necessary. [ABSTRACT FROM AUTHOR]

Three groups of industrial uranium deposits that differ in the distribution of lanthanides in U oxides have been recognized. A dependence of the REE distribution type on the Yttrium content and Yttrium index YI = (La + Ce)/Y that controls the formation of REE phases capable of selective accumulation of lanthanides has been discovered. This indicates the important role of crystal-chemical fractionation in the distribution of lanthanides. Preferable accumulation of Sm-Gd by U oxides has been found to occur at relatively low contents of Y. In Proterozoic uranium deposits, the yttrium specialization of oxides predominates, while in most Phanerozoic deposits the lanthanum-cerium specialization is typical. These results extend the possibilities of using REEs in ores for purposes of study of the genesis of various uranium deposits. [ABSTRACT FROM AUTHOR]

The uneven character of the distribution of O/O and U/U values was established in the vertical cross section of the productive sequence of the Dybryn uranium deposit (Vitim uranium-ore region, Buryatia). Both a deficiency and an excess of U in relation to the equilibrium U/U ratio in the vertical sequence may provide evidence for the extremely low rate of the infiltration water flow. The behavior of oxygen isotope characteristics for different size fractions of terrigenous rocks provides evidence for active uranium redistribution and openness of the isotope system of this element during interaction of terrigenous-sedimentary rocks with infiltration waters. [ABSTRACT FROM AUTHOR]

The variations in U/U values accompanying mobilization of U by fracture waters from uranium-bearing rocks, in which U occurs as a fine impregnation of oxides and silicates, were studied by the high-precision (±0.07‰) MC-ICP-MS method. Transition of U into the aqueous phase in the oxidized state U(VI) is accompanied by its isotope fractionation with enrichment of dissolved U(VI) in the heavy isotope U up to 0.32‰ in relation to the composition of the solid phases. According to the sign, this effect is consistent with the tendency of the behavior of U and U upon interaction of river waters with rocks of the catchment areas [11] and with the effect observed during oxidation of uraninite by the oxygen-bearing NaHCO solution [12]. [ABSTRACT FROM AUTHOR]

In recent years, the use of nanotechnology in human and veterinary medicine has made great progress, which could be a major breakthrough in addressing certain problems, including in the field of animal reproduction. Examples of potential applications make it possible to introduce nanotechnological methods of regulating reproductive function into practice more widely to promote livestock development. Studying the action of nanoparticles of dioxide silicon allows to optimize the methods of cryopreservation of sperm, promotes understanding of the mechanisms of functioning of germ cells, ovarian follicles and embryos. Prospective biocidal nanopreparations have been developed, the use of which provides for the increases of animal fertilization, immunobiological resistance, prevention of infertility and obtaining a healthy offspring. Nanoacquahelates have a modifying effect on physiological processes in animals, which is reflected in the activation of biosynthetic and energy processes in the body, stimulation of the cellular level of immunity. Use of them for both the treatment of animals suffering from mastitis and the stimulation of their reproductive function is suggested. In order to increase the therapeutic efficacy of the vitamin and hormone preparations, the addition of cerium-dioxide nanoparticles and rare-earth elements is used. Their application allows optimizing individual indicators of homeostasis and prooxidant-antioxidant system, to normalize the structure and function of the fetoplacental complex of pregnant animals and to increase the potential of newborn development, the effectiveness of therapy of females with mastodystrophy and gonadopathies, and males with andrological pathology. However, the precise mechanisms of the influence of nanoparticles on the body is still unknown; moreover, there are publications on the potential toxicity of nanoparticles that necessitates specific hypotheses and understanding of certain aspects of research. Thus, as nanotechnologies are in the early stages of development, it may take some time to produce meaningful results to perform the necessary research and clinical trials. This tool, which will evolve over the next few decades, will have major implications in veterinary science and reproduction inclusive. [ABSTRACT FROM AUTHOR]

There has been extensive research on the effects of evaporation on the isotopic ratio of lacustrine and marine water bodies; however, there are limited data on how ablation or sublimation from lake or sea ice influences the isotopic ratio of the residual water body. This is a challenging problem because there remains uncertainty on the magnitude of fractionation during sublimation and because ablation can involve mixed-phase processes associated with simultaneous sublimation, melting, evaporation, and refreezing. This uncertainty limits the ability to draw quantitative inferences on changing hydrological budgets from stable isotope records in arctic, Antarctic, and alpine lakes. Here, we use in situ measurements of the isotopic ratio of water vapor along with the gradient diffusion method to constrain the isotopic ratio of the ablating ice from two lakes in the McMurdo Dry Valleys, Antarctica. We find that during austral summer, the isotopic fractionation of ablation was insignificant during periods of boundary layer instability that are typical during midday when latent heat is highest. This implies that the loss of mass during these periods did not yield any isotopic enrichment to the residual lake mass. However, fractionation increased after midday when the boundary layer stabilized and the latent heat flux was small. This diurnal pattern was mirrored on synoptic timescales, when following warm and stable conditions latent heat flux was low and dominated by higher fractionation for a few days. We hypothesize that the shifting from negligible to large isotopic fractionation reflects the development and subsequent exhaustion of liquid water on the surface. The results illustrate the complex and nonlinear controls on isotopic fractionation from icy lakes, which implies that the isotopic enrichment from ablation could vary significantly over timescales relevant for changing lake volumes. Future work using water isotope fluxes for longer periods of time and over additional perennial and seasonal ice-covered lake systems is critical for developing models of the isotopic mass balance of arctic and Antarctic lake systems. [ABSTRACT FROM AUTHOR]

A significant change in the properties of mountainous meadow soils of the Ai-Petri Plateau has taken place under the impact of artificial plantations of pine, birch, and larch created in the Crimean highlands in the middle of the 20th century. In comparison with the soils under meadow vegetation, the soils under forest vegetation are characterized by an increased content of large aggregates, a decrease in the humus content, and an increase in the soil acidity and in the iron content of the organomineral compounds. The most dramatic changes in the structural state of the soils are observed under the plantations of pine. The changes in the acidity and the iron content are most pronounced under larch stands. The decrease in the humus content is observed under all tree species. Thus, in the soil layer of 0-10 cm under pine, birch, and larch stands, the content of Corg is 1.2, 1.3, and 1.4 times lower, respectively, than that in the soil under meadow vegetation. [ABSTRACT FROM AUTHOR]

Contrast variations in the type of REE distribution from a distinctly negative mode to a positive mode is revealed in zonal fluorites of Eastern Transbaikal, with a pronounced decrease in the Ce/Y ratios in successive zones of increasing Y accompanied by a gradual decrease in the temperature and salinity of fluid inclusions in the fluorites. It is assumed that these facts are caused by the appearance of nm-size phases of REE minerals characterized by various crystalline structures and demonstrating selective concentrations of lanthanides, i.e., exhibiting a crystal-chemical differentiation of REEs that is widespread in the processes of mineral formation. Based on this natural mechanism, the development of a procedure of selective REE extraction from the concentrates is proposed. The primary laboratory experiments resulted in the discovery of the difference in REE concentrations in the sediment and filtrate with the separation coefficient varying by a factor of 76. The results obtained allow one to expect a true separation possibility for Nd along with the medium and heavy REEs. In view of the data obtained, the crystalline-chemical separation of REEs has some advantages compared to the processes currently used, especially extraction. [ABSTRACT FROM AUTHOR]

This work presents the results of U-Pb geochronological studies of alkaline granites of the Aralaul complex of Northern Kazakhstan, which allow one to substantiate their Late Silurian (420 ± 4 Ma) age. Taking into consideration the previously obtained data, we propose a new development scheme of Paleozoic granitoid magmatism in Northern Kazakhstan, which includes Late Ordovician granite-granodiorite (Zerenda and Krykkuduk), Early Silurian granite-leucogranite (Borovoe and Karabulak), Late Silurian granosyenites-granite (Aralaul), and Early Devonian (Balkashino and Orlinogorsk) complexes. [ABSTRACT FROM AUTHOR]

The evolution of the geological structure in the Southern Argun' Region is studied in terms of changing geodynamic conditions of the Proterozoic, Caledonian, and Variscan Tectonomagmatic Cycles, which also under Mesozoic tectonomagmatic activation led to the formation of latite igneous rocks enriched in Au, Cu-Mo, Pb-Zn-Ag, volcanic and plutonic complexes of the caldera structures with Mo-U, Pb-Zn, and fluorite ores, and rare-metal granites with a Sn-W-Li-Ta spectrum. [ABSTRACT FROM AUTHOR]

This paper discusses the state of the Arctic cryosphere during the second half of the twentieth century and describes major findings of observational evidence since the 1950s. Although glaciers have been retreating steadily from their Little Ice Age maximum positions for decades, Arctic sea ice extent and thickness began to decline and loss of mass from the Greenland ice sheet accelerated only in the 1990s. Rapid changes in cryospheric components have occurred in this century, affecting snow cover, Arctic sea ice extent, the mass balance of the Greenland ice sheet, and frozen ground temperatures. Projections for this century, based on model results from the Intergovernmental Panel on Climate Change, involve dramatic changes by 2100. [ABSTRACT FROM AUTHOR]

Yttrium ( Y)-based bioceramics are important materials in radiation therapy and biomedical applications. This paper describes a low-temperature method to prepare yttrium phosphate ( YPO4) and Y-doped calcium phosphate (Y-CaP) microspheres using CaP microspheres as template. The as-formed microspheres were characterized using X-ray diffraction, fourier transform infrared spectroscopy, scanning electron microscope, and energy dispersive X-ray spectroscopy, confirming the formation of YPO4 and Y-CaP microspheres. The process was based on the dehydration effect of ethanol to CaP materials and hydrated ions transportation in amorphous CaP microspheres. The procedure, owing to its simplicity, may provide a new sight for the preparation of Y or rare earth elements-based bioceramic materials. [ABSTRACT FROM AUTHOR]

This work presents the results of complex analysis of the field data and of mathematical modeling of the ice ring structure more than 4 km across, which was identified by the space images of South Baikal in April 2009. The measurements revealed that the ice thickness was 74 cm in the center of the structure, decreased to 43 cm at a distance of 2 km, and increased up to 70 cm and more beyond the ring. The ice water in the central part was warmer by 0.5°C and less saline (for 2 mg/kg) relative to the periphery of the structure. According to the tracer movements, the maximum velocities of the ice currents (3-4 cm/s) were observed at a distance of 2-3 km from the center of the structure with minimum ice thickness. The event was modeled using several mathematical models of various scales. The 3-D nonhydrostatic modeling of the large-scale processes on the basis of the temperature measured in the area of the structure showed the presence of local anticyclonic circulation, where the velocities of the currents increased up to the maximum (5-7 cm/s) at the distance of 2-3 km from the center and then decreased. The variations in the ice thickness in the area of the ring structure were modeled on the basis of these calculation results. The ice thicknesses determined in the context of the Stefan problem for the 2-D axis-symmetrical temperature distribution model are close to the measured ones. According to the model, the formation of the ring structure spans a period of 25-35 days. The origination of the dark ring on the satellite images is related to the lower ice thickness relative to the ambient areas and to the water level in microfractures closer to the ice surface. [ABSTRACT FROM AUTHOR]

Eu2+ and Mn2+ coactivated β- Ca3( PO4)2 ( TCP) phosphors have been prepared by high-temperature solid-state reaction. The site occupation and photoluminescence properties of Eu2+ and Mn2+ have been identified and discussed in detail. The energy transfer from Eu2+ to Mn2+ in TCP: Eu2+, Mn2+ phosphors has been validated and demonstrated to be a resonant type via a dipole-quadrupole mechanism, and the critical distance ( R C) calculated by concentration quenching method is 21.76 Å. A color-tunable emission from violet-blue to red in TCP: Eu2+, Mn2+ phosphors can be realized via the energy transfer from Eu2+ to Mn2+ ions. [ABSTRACT FROM AUTHOR]

The article discusses the geochemical and isotopic data on the formation of the Mesozoic volcanics caldara in the western part of the Argun tectonic block in Russia. Topics discussed include compositions of basalt and trachybasalt rocks, role of geochemical properties of basalts in magmatic process and concetration of silicon dioxide in trachyrhyodacites.

The article discusses rare earth elements (REE) analysis in snow samples which is used as a sensitive indicator of environment pollution. It mentions technique used including spectrometry with inductively coupled plasma (ICP-MS), quadrupole mass spectrometer, and filtration and precipitation. It informs that the influence of aerosol and the limits of biosphere persistence in relation to integral chemical pollution.

The results of research performed in the Faculty of the Chemical Technology of Glass and Sitals at the D. I. Mendeleev Russian Chemical Technology University over the last five years are summarized. [ABSTRACT FROM AUTHOR]

A diagram representing the phase relationships in the Ca3( PO4)2- CePO4 phosphate system has been developed on the basis of results obtained using thermal analysis ( DTA/ DSC/ TG), X-ray diffraction ( XRD), and scanning electron microscopy ( SEM/ EDS) methods. One intermediate compound with formula Ca3 Ce( PO4)3 occurs in the Ca3( PO4)2- CePO4 system at temperature exceeding 1275°C. The compound melts at 1833°C and has one structural form. In the system a solid solution, having the structure of low-temperature form of calcium phosphate Ca3−3 x Ce x( PO4)2− x (where x is a molar fraction of CePO4), exists. The temperature and concentration range of the solid solution has been determined. It has been shown that the Ca9 Ce( PO4)7 phase should be understood as a limited solid solution with x = 0.25. [ABSTRACT FROM AUTHOR]

Isotopic content of the snow and firn thickness is assumed to be altered significantly due to the post-depositional (PD) mass- and isotope exchange with the atmospheric water vapor. If so, these effects should be accounted for in the ice core-based isotope-temperature paleo-reconstructions. In order to study the intensity of the PD processes we set up a series of laboratory experiments. In this paper we describe in detail the experimental technique and briefly overview preliminary results. It is shown that the PD modifications in the upper layer of snow thickness are noticeably strong even under such a low temperature as -35°C (the value typical for the Central Antarctic summer). It is demonstrated that the PD isotopic changes in snow can be approximated as a linear function of the relative mass loss due to snow sublimation. Possible applications for improving the isotope-temperature paleo-reconstructions are shortly discussed. [ABSTRACT FROM AUTHOR]

Eu3+-doped (1–12 mol%) calcium hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) powders were synthesized by a precipitation method and their photoluminescence (PL) properties were investigated. Eu has a limited solubility in HA and Eu2O3 was detected by X-ray diffraction above 3% doping, whereas a nearly single β-phase was obtained up to 6% doping in TCP but EuPO4 appeared in the 12% Eu-doped specimen. Electron spin resonance measurement confirmed that europium ions exist as Eu3+ in both samples. Eu3+-doped HA exhibited a strong emission at 575 nm with several minor peaks at 610–640 nm and Eu3+-doped TCP had an intense emission at 613 nm with secondary peaks at 590–600 nm, which were consistent with the earlier reports determined at low temperatures. In Eu-doped TCP, the PL intensity increased with increasing calcination temperature without phase transformation. The more the Eu added, the higher the PL intensity obtained in both cases. [ABSTRACT FROM AUTHOR]

The viral particles (about 30 nm in diameter) that contain dsRNAs (2.0 and 6.3 kbp) encapsidated by a coat of protein were detected in a mycocin-secreting strain of Cystofilobasidium infirmominiatum isolated from plants in an oak forest (Moscow region). The mycocin with a molecular mass above 15 kDa is fungicidal (maximum activity at pH 4.5) and active mainly against some species of the Cystofilobasidiales and Filobasidiales (‘Cryptococcus aerius’ clade). Curing by incubation at elevated temperature resulted in the concomitant loss of dsRNAs and mycocinogenic activity, and cured derivatives became sensitive to the mycocin produced by the parent strain. [Copyright &y& Elsevier]

Mycocin production was demonstrated in Trichosporon pullulans, which is a dominant member of the yeast community in tree exudates released in the early spring (spring sap). Mycocin synthesis was associated with dsRNA-containing virus-like particles. Natural strains of Tr. pullulans free of dsRNA have a sensitive phenotype, and a mycocinogenic strain cured of small dsRNA becomes sensitive to its own mycocin. The mycocin studied was active against isolates from tree exudations only but not against Tr. pullulans strains isolated from other habitats. No activity was found against any other yeast species. The competitive advantage of mycocin production at the population level was exemplified by the predominance of mycocinogenic strains both in laboratory model communities and in natural populations. [Copyright &y& Elsevier]