Mineralogy and geochemistry of tellurium in the some mining sites of Transbaikalia

The first results of the study of the occurrence and mineral forms of tellurium in hypogenic and hypergenic conditions on the example of some deposits in Transbaikalia are presented in the article. Their paragenesis and the variations of tellurium content in ores and the hypergenesis zone are considered. Experiments on water leaching of tellurium, bismuth, lead, uranium and silver were carried out. The physicochemical model of mineral associations with the participation of these elements in conditions of the hypergenesis zone was calculated

Local diversity and fine-scale organization of receptive fields in mouse visual cortex

Many thousands of cortical neurons are activated by any single sensory stimulus, but the organization of these populations is poorly understood. For example, are neurons in mouse visual cortex--whose preferred orientations are arranged randomly--organized with respect to other response properties? Using high-speed in vivo two-photon calcium imaging, we characterized the receptive fields of up to 100 excitatory and inhibitory neurons in a 200 μm imaged plane. Inhibitory neurons had nonlinearly summating, complex-like receptive fields and were weakly tuned for orientation. Excitatory neurons had linear, simple receptive fields that can be studied with noise stimuli and system identification methods. We developed a wavelet stimulus that evoked rich population responses and yielded the detailed spatial receptive fields of most excitatory neurons in a plane. Receptive fields and visual responses were locally highly diverse, with nearby neurons having largely dissimilar receptive fields and response time courses. Receptive-field diversity was consistent with a nearly random sampling of orientation, spatial phase, and retinotopic position. Retinotopic positions varied locally on average by approximately half the receptive-field size. Nonetheless, the retinotopic progression across the cortex could be demonstrated at the scale of 100 μm, with a magnification of ≈ 10 μm/°. Receptive-field and response similarity were in register, decreasing by 50% over a distance of 200 μm. Together, the results indicate considerable randomness in local populations of mouse visual cortical neurons, with retinotopy as the principal source of organization at the scale of hundreds of micrometers.status: publishe

Thermodynamic equilibria of tailings dump pond water of Sherlovaya Gora tin-polymetallic deposit (Transbaikalia)

The potential toxic elements (Be, U, As, Cd, Pb, Sb, Bi) were detected for mine landscape of Sherlovaya Gora tin-polymetallic deposit. Thermodynamic calculation of equilibrium for tailings dump pond water was carried out by means of “Selektor” program complex based on Gibbs free energy minimization algorithm at 25°C and 1 bar total pressure. It turned out that the mine water is supersaturated with respect to many sulphates of Ca, Mg, Sr, Zn, K, Cu, Ni, Cd, Be, Al, Ce and Y, fluorides of (Ln and Y, Sc), and Y phosphate

The geochemical features of ores and technosoils of tailing gold-molybdenum mine Davenda in East Transbaikalia

New data on the mineral and chemical composition of the ore, host rocks and technosoils of tailings gold-molybdenum deposit Davenda are outlined. The mineral composition of the ore (%): quartz (96), molybdenite (1, but on average 0.26), pyrite (7), chalcopyrite (2), sphalerite (0.07), galena (to.1), sulphosalts (0.02), bismuthinite (0.2), scheelite (up to 0.02), tungsten (up to 0.01), bornite (0.03), tetradymite (to 0.001) emplektite (rare occurrences) and gold (up to1817g/t). In the oxidation zone developed various sulfates, including large (up to10 cm) gypsum crystals, chalkanthite, malachite, azurite, brochantite, molybdenite, ferrimolybdite. The contents of the main chemical elements, which compose technosoils of tailing, exeed their clarks. Exceptions are zinc, tin, and yttrium. Especially high concentration factors for arsenic, bismuth and molybdenum, which indicates the imperfection of applied technologies of the ores enrichment. The distribution of chemical elements in the geotechnogenic system: productive mineral complex (ore + host rock)→soil→technosoils →plants. Revealed the share of Mo, Zn, Cu, Pb mobile form, in technosoils. Identified acid-base characteristics of technosoils. It was found that the most important of the mobile forms is a water-acid-ion exchange, to a much lesser extent - organic elements