Archaeomagnetic studies of materials from the Gorelyi Les and Ust-Khaita monuments (Eastern Siberia)

Archaeomagnetic studies of materials from archaeological monuments of the Irkutsk and Baikal regions provided new constraints on the geomagnetic intensity variation in Eastern Siberia for the interval from the 5th millennium BC through the 1st millennium AD. Material from the Gorelyi Les and Ust-Khaita multilayer archaeological monuments of the Irkutsk region is dated according to layer depths of deposits. Data on the geomagnetic intensity obtained from archaeomagnetic studies corroborate the validity of this method of dating. It is established that the average level of the geomagnetic intensity smoothly rose in the interval from the 5th millennium BC through the 1st millennium AD, with faster variations being superimposed on this trend. The pattern of the geomagnetic intensity variation is similar to those in other Eurasian regions.     

Late Precambrian Metamorphic Complexes of the Ulutau Massif (Central Kazakhstan): Age,Composition, and Formation Settings of Protoliths

Geotectonics - This work presents the results of a study of metamorphic rocks of the Bekturgan and Balazhezdy groups of the Precambrian Ulutau massif (Central Kazakhstan), which have been...     

Estimating the impact force generated by granular flow on a rigid obstruction

Flowing sediments such as debris and liquefied soils could exert a tremendous amount of force as they impact objects along their paths. The total impact force generally varies with slope angle, velocity at impact, and thickness of the flowing sediment. Estimation of the impact force of flowing sediments against protective measures such as earth retaining structures is an important factor for risk assessment. In this paper, we conduct small-scale laboratory physical modeling of sand flow at different slopes and measure the impact force exerted by this material on a fixed rigid wall. We also conduct numerical simulations in the Eulerian framework using computational fluid dynamics algorithms to analyze and reproduce the laboratory test results. The numerical simulations take into consideration the overtopping of the wall with sand, which influenced the measured impact force–time history responses. In addition, the numerical simulations are shown to capture accurately the change of the impact force with slope angle. Finally, the modeling approach conducted in this study is used to estimate the quasi-static force generated by the sediment as it comes to rest on the wall following impact.     

THERMAL INFRARED IMAGERY OF DESERT LANDSCAPES

The author illustrates the application of thermal infrared machinery to prospecting for mineral deposits in desert areas. The technique is presented with details pertaining to an oil field in Western Kazakhstan and a copper deposit in Southern Kazakhstan. Translated from: Vestnik Moskovskogo Universiteta, geografiya, 1983, No. 5, pp. 60-64.     

New active galactic nuclei among the INTEGRAL and SWIFT X-ray sources

We present the results of our optical identifications of a set of X-ray sources from the INTEGRAL and SWIFT all-sky surveys. The optical data have been obtained with the 1.5-m Russian-Turkish Telescope (RTT-150). Nine X-ray sources have been identified with active galactic nuclei (AGNs). Two of them are located in the nearby spiral galaxies MCG-01-05-047 and NGC 973 seen almost edge-on. One source, IGR J16562-3301, is probably a BL Lac object (blazar). The remaining AGNs are observed as the starlike nuclei of spiral galaxies whose spectra exhibit broad emission lines. The relation between the hard X-ray (17–60 keV) luminosity and the [O III] 5007 line luminosity, log L _x/L _{[O III]} ≈ 2.1, holds good for most of the AGNs detected in hard X rays. However, the luminosities of some AGNs deviate from this relation. The fraction of such objects can reach ～20%. In particular, the [O III] line flux is lower for two nearby edge-on spiral galaxies. This can be explained by the effect of absorption in the galactic disks.     

Comparative hydrochemistry of five nested catchments located in the upper part of the Barcés river watershed (A Coruña,NW Spain)

259 stream water and 21 bulk precipitation samples have been studied between April 2008 and December 2010 in order to assess baseline hydrochemical conditions in a rural area of NW Spain. Stream waters are related to five nested catchments (<10 km²) with apparent low mean residence times. Their hydrochemical characteristics are closely related to bulk precipitation although clear evidences of seasonal (flushing, dilution, sediment desorption, etc.), lithological (schist vs. granite substrate) and anthropogenic (land use, contamination) effects are also described.     

The ultraviolet line spectrum of the soft X-ray transient XTE J1118+480: a CNO-processed core exposed

We compare ultraviolet (UV) spectra of the recent soft X-ray transients XTE J1118+480 and XTE J1859+226. The emission line strengths in XTE J1118+480 strongly suggest that the accreting material has been CNO processed. We show that this system must have come into contact with a secondary star of about 1.5 M_⊙, and an orbital period ∼15 h, very close to the bifurcation value at which the nuclear and angular momentum loss time-scales are similar. Subsequent evolution to the current period of 4.1 h was driven by angular momentum loss. In passing through a period of 7.75 h the secondary star would have shown essentially normal surface abundances. XTE J1118+480 could thus represent a slightly later evolutionary stage of A0620-00. We briefly discuss the broad Ly α absorption wings in XTE J1118+480.     

A correlation between the distributions of pulsars and emission measures in the galaxy

A correlation has been detected between the volume density of pulsars and the density of interstellar ionized gas on scales of more than 500 pc in Galactic longitude and 200 pc in Galactic latitude. On smaller scales, the correlation is present only for pulsars with ages less than 60000 years, which are located predominantly near supernova remnants and H II regions. This all indicates that pulsars are born in regions with high concentrations of interstellar gas. The minimum emission measures observed in the directions toward pulsars are inversely proportional to the pulsar ages. It is concluded that the ionized gas in the vicinities of a number of pulsars was formed during supernova explosions, and corresponds to Strömgren zones. The ionization of the gas in these zones requires a radiation energy on the order of 10⁵⁰–10⁵¹ erg.     

Geometry of the modelled freshwater/salt-water interface under variable-density-driven flow (Pétrola Lake,SE Spain)

Hydrogeology Journal - Pétrola Lake in southeast Spain is one of the most representative examples of hypersaline wetlands in southern Europe. The rich ecosystem and environmental importance of...