Correlation Properties of a Distribution of Objects from the PSCz Survey

The properties of a sample of IR galaxies from the Point Source Catalog z (PSCz) Survey were investigated using the correlation gamma function [(r) and ^*(r)]. The results with different volume-limited subsamples indicate that the regions of strong correlations (a power-law decrease in density with distance with an exponent ₁ 1) are limited to a scale of 10-15 Mpc. A break is present at this scale in the dependences of log() on log(r) and of log(^*) on log(r). Such a break is also observed for various other samples of galaxies and clusters (at different scales). After the break the density dependence changes to another regime, corresponding to a fully uniform distribution for bright galaxies in the northern Galactic hemisphere. For some subsamples of the southern and northern hemispheres the latter regime corresponds to some decrease in density with distance. Indications of significant differences between the distributions of objects in the southern and northern hemispheres are obtained. It is shown that the section of the gamma function after the break, even when its extent is small, is a significant indicator of actual correlation properties of the distributions. The results of the analysis are in good agreement, on the whole, with preceding studies of the PSCz survey.     

Ferrospinels and petromagnetism of Siberian traps: A case study of traps drilled by the Norilsk borehole

Magnetic characteristics and compositions of ferromagnetic species of trap samples from the Norilsk borehole are studied; the borehole penetrated the complete section of a trappean rock sequence (nearly 3 km) represented by eight magmatic formations. The lowest (Ivakinskian) formation consists of rocks of the subalkalic type, and the remaining formations generally belong to the tholeiitic series. Primary ferromagnetic phases are represented by titanomagnetites with various ulvospinel concentrations in a solid solution. Three modes characterized by TiO₂ concentrations of 14.6, 18, and 23.9 wt % are revealed. The Ivakinskian rocks are most magnetized, and magnetization is low in core samples from depths of 1700–2500 m. Various magnetic characteristics have polymodal distributions of their values. Plateau basalt samples of the Ivakinskian Formation from other regions of Siberia, the Lory Plateau (Armenia), and Kamchatka are additionally studied. On the whole, titanomagnetites of plateau basalts were crystallized under the quartz-fayalite-magnetite (QFM) buffer conditions.     

Metallicity of Young and Old Stars in Irregular Galaxies

Based on archived images obtained with the Hubble Space Telescope, stellar photometry for 105 irregular galaxies has been conducted. We have shown the red supergiant and giant branches in the obtained Hertzsprung-Russel diagrams. Using the TRGB method, distances to galaxies and metallicity of red giants have been determined. The color index (V ? I) of the supergiant branch at the luminosity level M_I = ?7 was chosen as the metallicity index of red supergiants. For the galaxies under study, the diagrams have been built, in which the correlation can be seen between the luminosity of galaxies (M_B) and metallicity of red giants and supergiants. The main source of variance of the results in the obtained diagrams is, in our opinion, uncertainty inmeasurements of galaxy luminosities and star-forming outburst. The relation between metallicity of young and old stars shows that main enrichment of galaxies with metals has taken place in the remote past. Deviations of some galaxies in the obtained relation can possibly be explained with the fall of the intergalactic gas on them, although, this inconsiderably affects metallicities of the stellar content.     

New Data on Large Brown Bear (Ursus arctos L., 1758, Ursidae,Carnivora, Mammalia) from the Pleistocene in Yakutia

Doklady Earth Sciences - New finds of brown bear (Ursus arctos L., 1758) fossil remains from the territory of Yakutia, namely, skulls and mandibular bones, have been investigated. The new finds are...     

On the seismic regime of the Japan region before the Tohoku mega-earthquake (M w = 9)

The seismic regime taking place before the Tohoku mega-earthquake was studied using the catalog of the Japan Meteorological Agency (JMA). We show that the Tohoku earthquake was preceded by a 6–7-year period of regional reduction in the b-value and in the rate of main shocks. The space-time regions that involved precursory activation were nearly identical with the predictive phenomena that were previously detected by A.A. Lyubushin from an analysis of seismic noise based on data from the Japanese F-net. We discovered a previously unknown effect of correlation between the number of main shocks and the b-value. Both the ordinary foreshock activation and the longer weaker tendency, which consist in a precursory increase in the seismicity rate, were identified in the vicinities of M ≈ 7 Japanese earthquakes (similarly to the seismicity in the Generalized Vicinities of large earthquakes based on worldwide data).     

Isotopic-hydrochemical study of changes in the dynamics and geoenvironmental conditions of groundwater in urban areas resulting from the development of aquifers

An integrated study with the use of uranium-isotope and microelement hydrogeochemical methods showed the possibility of studying changes in the dynamics and geoenvironmental condition of groundwater in an urban area by the indicator modeling of groundwater formation and circulation, as well as interaction of waters from different horizons, including water ingress from deeper aquifers.     

Sizes of Stellar Subsystems of Disk Galaxies and the Metallicities of Red Giants

Stellar photometry of 53 low-mass spiral and irregular galaxies has been carried out using archival frames obtained by the Hubble Space Telescope. Young and old stars (blue supergiants and red giants) are distinguished on the resulting Hertzsprung–Russell diagrams, and the spatial sizes of the subsystems formed by these stars are determined. A correlation is found between the metallicities of red giants and the difference between the linear sizes of stellar systems of different ages. This dependence can be explained if the sizes of stellar subsystems expand over the lifetimes of galaxies, as well as the influence of the relationship between the mass of a galaxy and the metallicity of its stars.