Accumulation of natural radionuclides (Be, Pb) and micro-elements in mosses, lichens and cedar and larch needles in the Arctic Western Siberia.

This is a study of the atmospheric-origin natural radionuclides (Be and Pb) and a wide range of micro- and macro-element accumulation in mosses, lichens, cedar and larch needles in Arctic western Siberia (Yamal-Nenets Autonomous District). Based on the specific activities measurements of atmospheric precipitation markers (Be and Pb), this study found that the concentration of dust particles in the studied objects incrementally increases in the following order, from lowest concentration to highest: cedar needles, larch needles, lichens and mosses. Concentrations of Zr, Hf, Ti, Th, Fe, V, Li, Na, Si, Be, Y, rare earth elements (REE) and Sc in this area also increase in the same ascending sequence.

Onshore mud volcanoes as a geological source of mercury: Case study from the Kerch Peninsula, Caucasus continental collision zone.

Three mud volcanoes (MVs) in the Kerch Peninsula were studied as a geological source of mercury. The study focused on total mercury (THg) concentrations in MV waters, mud masses and plants colonizing MV areas; gaseous elemental mercury (GEM) in the atmosphere above MVs; and sulfide mercury (HgS) and HgCl species in representative samples of mud masses. THg concentrations in the illite-smectite mud masses ranged from 38 to 920 ng/g.

Experimental and Ab Initio Studies of Intrinsic Defects in "Antizeolite" Borates with a Ba(BO) Framework and Their Influence on Properties.

The porous Ba(BO) framework of the so-called "antizeolite" borates with channels along the axis is capable of accommodating various guest anionic groups, e.g. [BO], [F], [F], and [(Li,Na)F].

Incommensurately modulated crystal structure of flamite - natural analogue of \alpha _{\rm H}^{\prime}-CaSiO.

Crystal structures of unquenchable high-temperature polymorphs of CaSiO, important in cement chemistry, have eluded single-crystal X-ray analysis. However, the problem may be addressed by studying chemically stabilized CaSiO polymorphs at ambient temperature. Here an incommensurately modulated crystal structure of flamite [Pnma(0β0)00s, q = 0.

Dual clumped isotope thermometry resolves kinetic biases in carbonate formation temperatures.

Surface temperature is a fundamental parameter of Earth's climate. Its evolution through time is commonly reconstructed using the oxygen isotope and the clumped isotope compositions of carbonate archives. However, reaction kinetics involved in the precipitation of carbonates can introduce inaccuracies in the derived temperatures.

Dielectric ordering of water molecules arranged in a dipolar lattice.

Intermolecular hydrogen bonds impede long-range (anti-)ferroelectric order of water. We confine HO molecules in nanosized cages formed by ions of a dielectric crystal. Arranging them in channels at a distance of ~5 Å with an interchannel separation of ~10 Å prevents the formation of hydrogen networks while electric dipole-dipole interactions remain effective.

Effect of Oxygen on Diamond Crystallization in Metal-Carbon Systems.

In this article, we report the influence of oxygen concentration in the transition-metal solvent-catalyst on the crystallization processes, morphology, and defect-and-impurity content of diamond crystals. In a series of experiments, the concentration of oxygen ( ) in the growth system was varied by adding FeO to the charge, and the other parameters and conditions of the growth were constant: NiFe solvent-catalyst, = 6.0 GPa, = 1400 °C, and duration of 40 h.

Molecular hydrogen in minerals as a clue to interpret ∂D variations in the mantle.

Trace amounts of water dissolved in minerals affect density, viscosity and melting behaviour of the Earth's mantle and play an important role in global tectonics, magmatism and volatile cycle. Water concentrations and the ratios of hydrogen isotopes in the mantle give insight into these processes, as well as into the origin of terrestrial water. Here we show the presence of molecular H in minerals (omphacites) from eclogites from the Kaapvaal and Siberian cratons.

Optical and electronic properties of lithium thiogallate (LiGaS): experiment and theory.

We report the relation between the optical properties and electronic structure of lithium thiogallate (LiGaS) by performing XPS and XES measurements and theoretical calculations. According to the XPS measurements, the LiGaS crystals grown by the Bridgman-Stockbarger method possess promising optical qualities, low hygroscopicity and high stability upon middle-energy Ar-ion irradiation. The difference in the LiGaS band gaps obtained by theoretical calculations and experimental measurements was, for the first time, reduced down to 0.

Topologically Nontrivial Phase-Change Compound GeSbTe.

Chalcogenide phase-change materials show strikingly contrasting optical and electrical properties, which has led to their extensive implementation in various memory devices. By performing spin-, time-, and angle-resolved photoemission spectroscopy combined with the first-principles calculation, we report the experimental results that the crystalline phase of GeSbTe is topologically nontrivial in the vicinity of the Dirac semimetal phase. The resulting linearly dispersive bulk Dirac-like bands that cross the Fermi level and are thus responsible for conductivity in the stable crystalline phase of GeSbTe can be viewed as a 3D analogue of graphene.

Million-year lag times in a post-orogenic sediment conveyor.

Understanding how sediment transport and storage will delay, attenuate, and even erase the erosional signal of tectonic and climatic forcings has bearing on our ability to read and interpret the geologic record effectively. Here, we estimate sediment transit times in Australia's largest river system, the Murray-Darling basin, by measuring downstream changes in cosmogenic Al/Be/C ratios in modern river sediment. Results show that the sediments have experienced multiple episodes of burial and reexposure, with cumulative lag times exceeding 1 Ma in the downstream reaches of the Murray and Darling rivers.

Electrically Controlled Spin Injection from Giant Rashba Spin-Orbit Conductor BiTeBr.

Ferromagnetic materials are the widely used source of spin-polarized electrons in spintronic devices, which are controlled by external magnetic fields or spin-transfer torque methods. However, with increasing demand for smaller and faster spintronic components utilization of spin-orbit phenomena provides promising alternatives. New materials with unique spin textures are highly desirable since all-electric creation and control of spin polarization is expected where the strength, as well as an arbitrary orientation of the polarization, can be defined without the use of a magnetic field.

(Fe,Ni)P allabogdanite can be an ambient pressure phase in iron meteorites.

An orthorhombic modification of (Fe,Ni)P, allabogdanite, found in iron meteorites was considered to be thermodynamically stable at pressures above 8 GPa and temperatures of 1673 K according to the results of recent static high-pressure and high-temperature experiments. A hexagonal polymorphic modification of (Fe,Ni)P, barringerite, was considered to be stable at ambient conditions. Experimental investigation through the solid-state synthesis supported by ab initio calculations was carried out to clarify the stability fields of (Fe,Ni)P polymorphs.

Theoretical and experimental study on the electronic and optical properties of KRbPbBr: a promising laser host material.

The data on the electronic structure and optical properties of bromide KRbPbBr achieved by first-principle calculations and verified by X-ray spectroscopy measurements are reported. The kinetic energy, the Coulomb potential induced by the exchange hole, spin-orbital effects, and Coulomb repulsion were taken into account by applying the Tran and Blaha modified Becke-Johnson function (TB-mBJ), Hubbard U parameter, and spin-orbital coupling effect (SOC) in the TB-mBJ + U + SOC technique. The band gap was for the first time defined to be 3.

From Molten Calcium Aluminates through Phase Transitions to Cement Phases.

Crystalline calcium aluminates are a critical setting agent in cement. To date, few have explored the microscopic and dynamic mechanism of the transitions from molten aluminate liquids, through the supercooled state to glassy and crystalline phases, during cement clinker production. Herein, the first in situ measurements of viscosity and density are reported across all the principal molten phases, relevant to their eventual crystalline structures.

Exceptional Concentrations of Gold Nanoparticles in 1,7 Ga Fluid Inclusions From the Kola Superdeep Borehole, Northwest Russia.

In the drill core of the Kola super-deep borehole (SG-3, 12,262 m depth) gold-bearing rocks of Archaean age have been located at depths of 9,500 to 11,000 m. In veins, between 9,052 and 10,744 m, within this gold zone, quartz contains fluid inclusions with gold nanoparticles. There are 4 types of fluid inclusions (1) gas inclusions of dense CO, (2) liquid-vapor two-phase aqueous inclusions, (3) three-phase inclusions with NaCl daughter crystals, and (4) CO-aqueous inclusions.

Do Reproductive Modes and Swimming Ability Influence Occurrence of Non-Marine Ostracod (Crustacea) Species among Aquatic Habitats?

To gain a better understanding of the effect of reproductive modes and swimming ability on ostracod distribution, we visited 111 randomly selected aquatic sites in Kırşehir province. A total of 35 ostracods were newly reported for the area. The number of species with and without swimming setae was not statistically different, but numbers of sexual species was significantly lower than parthenogenetics.

The main pulse of the Siberian Traps expanded in size and composition.

Emplacement of large volumes of (sub)volcanic rocks during the main pulse of the Siberian Traps occurred within <1 m.y., coinciding with the end-Permian mass extinction.

Uranium and thorium contents in soils and bottom sediments of lake Bolshoye Yarovoye, western Siberia.

The uranium and thorium contents in the soils and bottom sediments of the Lake Bolshoye Yarovoye natural system correspond to the data for the steppe climate zone and are noticeably lower than the background values for the Altai Territory as a whole. Factors that reduce the content of uranium and thorium are: 1 - lighter grain size distribution of the substrate, and, accordingly, the soils in this area; 2 - low content of organic matter (high ash content at 600 °C); 3 - the presence of significant quantities of quartz and calcite; 4 - general salinization of soils and the development of the solonchak process; 5 - remoteness from the region of material removal from the Altai mountains with its uranium-thorium-bearing granites and various mineraliszation. The distribution of uranium and thorium in the soils of the catchment area is heterogeneous.

Mediterranean winter rainfall in phase with African monsoons during the past 1.36 million years.

Mediterranean climates are characterized by strong seasonal contrasts between dry summers and wet winters. Changes in winter rainfall are critical for regional socioeconomic development, but are difficult to simulate accurately and reconstruct on Quaternary timescales. This is partly because regional hydroclimate records that cover multiple glacial-interglacial cycles with different orbital geometries, global ice volume and atmospheric greenhouse gas concentrations are scarce.

Diamond-inclusion system recording old deep lithosphere conditions at Udachnaya (Siberia).

Diamonds and their inclusions are unique fragments of deep Earth, which provide rare samples from inaccessible portions of our planet. Inclusion-free diamonds cannot provide information on depth of formation, which could be crucial to understand how the carbon cycle operated in the past. Inclusions in diamonds, which remain uncorrupted over geological times, may instead provide direct records of deep Earth's evolution.

Quantifying hexagonal stacking in diamond.

Diamond is a material of immense technological importance and an ancient signifier for wealth and societal status. In geology, diamond forms as part of the deep carbon cycle and typically displays a highly ordered cubic crystal structure. Impact diamonds, however, often exhibit structural disorder in the form of complex combinations of cubic and hexagonal stacking motifs.

Protein/Ice Interaction: High-Resolution Synchrotron X-ray Diffraction Differentiates Pharmaceutical Proteins from Lysozyme.

Protein/ice interactions are investigated by a novel method based on measuring the characteristic features of X-ray diffraction (XRD) patterns of hexagonal ice (Ih). Aqueous solutions of four proteins and other solutes are studied using high-resolution synchrotron XRD. Two pharmaceutical proteins, recombinant human albumin and monoclonal antibody (both at 100 mg/mL), have a pronounced effect on the properties of ice crystals, reducing the size of the Ih crystalline domains and increasing the microstrain.

Scaling laws explain foraminiferal pore patterns.

Due to climate warming and increased anthropogenic impact, a decrease of ocean water oxygenation is expected in the near future, with major consequences for marine life. In this context, it is essential to develop reliable tools to assess past oxygen concentrations in the ocean, to better forecast these future changes. Recently, foraminiferal pore patterns have been proposed as a bottom water oxygenation proxy, but the parameters controlling foraminiferal pore patterns are still largely unknown.