Gamma-ray bursts from a close pulsar binary system?     

Ya. N. Istomin 《Astronomy Reports》2005,49(6):446-449

The close neutron-star binary system comprised of the radio pulsars PSR J0737-3039 A,B is discussed. An analysis of the observational data indicates that the wind from pulsar A, which is more powerful than the wind from pulsar B, strongly distorts the magnetosphere of pulsar B. A shock separating the relativistic wind from pulsar A and the corotating magnetosphere of pulsar B should form inside the light cylinder of pulsar B. A weakly diverging “tail” of magnetic field is also formed, which stores a magnetic energy on the order of 10³⁰ erg. This energy could be liberated over a short time on the order of 0.1 s as a result of reconnection of the magnetic-force lines in this “tail,” leading to an outburst of electromagnetic radiation with energies near 100 keV, with an observed flux at the Earth of 4 × 10^?11 erg cm^?2 s^?2. Such outbursts would occur sporadically, as in the case of magnetic substorms in the Earth’s magnetosphere.  相似文献   

On the Tilts Caused by Equilibrium Fluctuations of Atmospheric Pressure: Effect of Topography     

Tsurkis  I. Ya. 《Izvestiya Physics of the Solid Earth》2019,55(6):936-944

Izvestiya, Physics of the Solid Earth - Abstract—The influence of the relief on baric tilts is studied. Main attention is focused on two-dimensional problem. It is assumed that variations of...  相似文献   

Thermal anomalies on Savich Cone,Kikhpinych Volcano,Kamchatka: IR surveys and land-based observations for 30 years (1982 through 2012)     

O. F. Kardanova  I. K. Dubrovskaya  Ya. D. Murav’ev 《Journal of Volcanology and Seismology》2015,9(6):368-377

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High‐temperature gold‐copper extraction with chloride flux in lava tubes of Tolbachik volcano (Kamchatka)     

Vadim S. Kamenetsky  Alexander Belousov  Victor V. Sharygin  Liudmila M. Zhitova  Kathy Ehrig  Michael E. Zelenski  Ilya Chaplygin  Marina A. Yudovskaya  Pavel N. Nesterenko  Sergey M. Zakharov 《地学学报》2019,31(6):511-517

Subvolcanic environments in supra‐subduction zones are renowned for hosting epithermal deposits that often contain electrum and native gold, including bonanza examples. This study examined mineral assemblages and processes occurring in shallow‐crust volcanic settings using recent eruption (2012–2013) of the basaltic Tolbachik volcano in the Kamchatka arc. The Tolbachik eruptive system is characterized by an extensive system of lava tubes. After cessation of magma input, the tubes maintained the flow of hot oxidized gases that episodically interacted with the lava surfaces and sulphate‐chloride precipitates from volcanic gases on these surfaces. The gas‐rock interaction had strong pyrometamorphic effects that resulted in the formation of molten salt, oxidized (tenorite, hematite, Cu‐rich magnesioferrite) and skarn‐like silicate mineral assemblages. By analogy with experimental studies, we propose that a combination of these processes was responsible for extraction of metals from the basaltic wall rocks and deposition of Cu‐, Fe‐ and Cu‐Fe‐oxides and native gold.  相似文献   

The first record of “spelaeoid” bears in Arctic Siberia     

Andrei V. Sher  Jacobo Weinstock  Gennady F. Baryshnikov  Sergey P. Davydov  Gennady G. Boeskorov  Vladimir S. Zazhigin  Pavel A. Nikolskiy 《Quaternary Science Reviews》2011,30(17-18):2238-2249

For a long time, “spelaeoid” (cave-bear-like) bears, Ursus (Spelearctos) spp., were believed to be almost purely European animals. Their geographic range has recently been extended to the east, in southern Siberia, Transbaikalia, Kirghizia, Mongolia and Korea. Two unexpected new findings, presented here in detail, significantly change existing views on the distribution of cave bears; both were found in North-Eastern Siberia, far beyond the Arctic Circle, more than 1500 km to the north-east of the previously accepted range.One of the fossils is a mandible, found near the town of Cherskiy at 68.73°N, 161.38°E. The analysis of local geology and accompanying mammal fossils suggests that it comes from the Olyorian Fauna (Early to early Middle Pleistocene). Morphologically, the Cherskiy mandible is closest to Ursus savini, a small middle Pleistocene cave bear from the British Cromer Forest-bed Formation, but differs in having a slightly more advanced dentition, and thus it is described as a new subspecies Ursus savini nordostensis. Another newly recognized fossil of the “spelaeoid” bear is an astragalus found at the Oskhordokh site at 67.54°N, 135.67°E, on a large gravel bar on the right bank of the Adycha River. This specimen is attributed to Ursus cf. deningeri.The paper also presents an interesting example of the interaction between classical and “molecular” palaeontology.The new finds significantly change existing ideas on the ecology and evolution of cave bears, some of the most remarkable members of the extinct Pleistocene megafauna.  相似文献   

Paleontological records indicate the occurrence of open woodlands in a dry inland climate at the present-day Arctic coast in western Beringia during the Last Interglacial     

Frank Kienast  Sebastian Wetterich  Svetlana Kuzmina  Lutz Schirrmeister  Andrei A. Andreev  Pavel Tarasov  Larisa Nazarova  Annette Kossler  Larisa Frolova  Viktor V. Kunitsky 《Quaternary Science Reviews》2011,30(17-18):2134-2159

Permafrost records, accessible at outcrops along the coast of Oyogos Yar at the Dmitry Laptev Strait, NE-Siberia, provide unique insights into the environmental history of Western Beringia during the Last Interglacial. The remains of terrestrial and freshwater organisms, including plants, coleopterans, chironomids, cladocerans, ostracods and molluscs, have been preserved in the frozen deposits of a shallow paleo-lake and indicate a boreal climate at the present-day arctic mainland coast during the Last Interglacial. Terrestrial beetle and plant remains suggest the former existence of open forest-tundra with larch (Larix dahurica), tree alder (Alnus incana), birch and alder shrubs (Duschekia fruticosa, Betula fruticosa, Betula divaricata, Betula nana), interspersed with patches of steppe and meadows. Consequently, the tree line was shifted to at least 270 km north of its current position. Aquatic organisms, such as chironomids, cladocerans, ostracods, molluscs and hydrophytes, indicate the formation of a shallow lake as the result of thermokarst processes. Steppe plants and beetles suggest low net precipitation. Littoral pioneer plants and chironomids indicate intense lake level fluctuations due to high evaporation. Many of the organisms are thermophilous, indicating a mean air temperature of the warmest month that was greater than 13 °C, which is above the minimum requirements for tree growth. These temperatures are in contrast to the modern values of less than 4 °C in the study area. The terrestrial and freshwater organism remains were found at a coastal exposure that was only 3.5 m above sea level and in a position where they should have been under sea during the Last Interglacial when the global sea level was 6–10 m higher than the current levels. The results suggest that during the last warm stage, the site was inland, and its modern coastal situation is the result of tectonic subsidence.  相似文献   

Spatial and temporal variability of stable isotopes (δ18O and δ2H) in surface waters of arid,mountainous Central Asia     

Huawu Wu  Jinglu Wu  Kadyrbek Sakiev  Jinzhao Liu  Jing Li  Bin He  Ya Liu  Beibei Shen 《水文研究》2019,33(12):1658-1669

Characterization of spatial and temporal variability of stable isotopes (δ¹⁸O and δ²H) of surface waters is essential to interpret hydrological processes and establish modern isotope–elevation gradients across mountainous terrains. Here, we present stable isotope data for river waters across Kyrgyzstan. River water isotopes exhibit substantial spatial heterogeneity among different watersheds in Kyrgyzstan. Higher river water isotope values were found mainly in the Issyk‐Kul Lake watershed, whereas waters in the Son‐Kul Lake watershed display lower values. Results show a close δ¹⁸O–δ²H relation between river water and the local meteoric water line, implying that river water experiences little evaporative enrichment. River water from the high‐elevation regions (e.g., Naryn and Son‐Kul Lake watershed) had the most negative isotope values, implying that river water is dominated by snowmelt. Higher deuterium excess (average d = 13.9‰) in river water probably represents the isotopic signature of combined contributions from direct precipitation and glacier melt in stream discharge across Kyrgyzstan. A significant relationship between river water δ¹⁸O and elevation was observed with a vertical lapse rate of 0.13‰/100 m. These findings provide crucial information about hydrological processes across Kyrgyzstan and contribute to a better understanding of the paleoclimate/elevation reconstruction of this region.  相似文献   

Assessment of the ground motion levels for the Vrancea (Romania) November 1940 earthquake     

Florin Pavel  Radu Vacareanu 《Natural Hazards》2015,78(2):1469-1480

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Solubility and migration ability of rhodium in natural conditions: model experimental data     

I. Ya. Koshcheeva  I. V. Kubrakova  N. V. Korsakova  O. A. Tyutyunnik 《Geochemistry International》2016,54(7):624-632

The contents of dissolved rhodium species in the near-neutral environments have been studied for the first time and data on the interaction of Rh with organic matters of natural waters and its sorption behavior during contact with the components of geochemical barriers were obtained. The solubility method was used to analyze the behavior of rhodium hydroxide in the Rh(OH)_x–H₂O and Rh(OH)_x–H₂O–FA (fulvic acids) systems. The possible contents of inorganic species of rhodium and its compounds with humic organic ligands were determined within the pH range typical of surface waters. The solubility of rhodium shows a twoorder- of magnitude increase in the presence of humic matters (FA). The sorption interaction of the soluble rhodium species with the main components of geochemical barriers such as iron oxyhydroxides (III), (including fulvic-acid modified ones), alumosilicates, and precipitates of humic acids in contact with natural waters was studied. It was revealed that rhodium has the high affinity to all studied materials; its species are sorbed by ferrihydrite within several hours. It is suggested that rhodium is mainly transferred as colloid with suspended particulate matters of waters and then is accumulated in bottom sediments. The differences revealed in the sorption behavior of Pt(IV), Pd(II) and Rh(III) may be used to predict the distribution of the considered platinum group elements between the components of ecosystems.  相似文献   

An algorithm to retrieve precipitation with synthetic aperture radar     

谢亚楠  刘志坤  安大伟 《Acta Meteorologica Sinica》2016,30(3):401-411

This paper presents a new type of rainfall retrieval algorithm, called the model-oriented statistical and Volterra integration. It is a combination of the model-oriented statistical (MOS) and Volterra integral equation (VIE) approaches. The steps involved in this new algorithm can be briefly illustrated as follows. Firstly, information such as the start point and width of the rain is obtained through pre-analysis of the data received by synthetic aperture radar (SAR). Secondly, the VIE retrieval algorithm is employed over a short distance to obtain information on the shape of the rain. Finally, the rain rate can be calculated by using the MOS retrieval algorithm. Simulation results show that the proposed algorithm is effective and simple, and can lead to time savings of nearly 50% compared with MOS. An example of application of SAR data is also discussed, involving the retrieval of precipitation information over the South China Sea.  相似文献