Long-term solar wind variations in the 20th–23rd solar activity cycles according to radio-astronomical data

We analyzed the variations of the interplanetary plasma parameters, obtained from radio astronomical observations of scintillations of cosmic radio sources during four 11-year cycles of solar activity, from 1966 to present. It is shown that the state of the interplanetary plasma permanently changes in conformity with cyclicity in the solar activity. In the studied time period, besides the 11-year variations in the velocity and scintillation index, there is also an increasing linear trend of these variables, which is presumably due to a secular 80–90-year cycle of solar activity. The observed differences between the 11-year variations and trends in the solar wind velocity and interplanetary scintillation index suggest that the 11-year and secular cycles have different origins. It is found that these trends occur in this time period in each link of the Sun-Earth system: in the solar activity indices, in the characteristics of the interplanetary medium, and practically in all characteristics of the geophysical, demographical, medical, and other Earth’s processes. From the entire set of facts we can conclude that most of the analyzed Earth’s processes are dominated not by anthropogenic factors, but by the effects of the secular cyclic processes of the solar activity.     

Critical loads of benzo(a)pyrene on urban soils

Doklady Earth Sciences - The resistance of urban soils to organic contaminants and their capability for self-purification from benzo(a)pyrene were evaluated with the use of the concept of critical...     

Photoluminescence of silicon‐vacancy defects in nanodiamonds of different chondrites

Photoluminescence spectra show that silicon impurity is present in lattice of some nanodiamond grains (ND) of various chondrites as a silicon‐vacancy (SiV) defect. The relative intensity of the SiV band in the diamond‐rich separates depends on chemical composition of meteorites and on size of ND grains. The strongest signal is found for the size separates enriched in small grains; thus, confirming our earlier conclusion that the SiV defects preferentially reside in the smallest (≤2 nm) grains. The difference in relative intensities of the SiV luminescence in the diamond‐rich separates of individual meteorites are due to variable conditions of thermal metamorphism of their parent bodies and/or uneven sampling of nanodiamond populations. Annealing of separates in air eliminates surface sp²‐carbon; consequently, the SiV luminescence is enhanced. Strong and well‐defined luminescence and absorption of the SiV defect is a promising feature to locate cold (<250 °C) nanodiamonds in space.     

The Schlema–Alberoda five-element uranium deposit,Germany: An example of self-organizing hydrothermal system

As a result of integrating geological, mineralogical, and geochemical data on the unique Schlema–Alberoda five-element uranium deposit situated in Federal Republic of Germany and explored in detail down to a depth of 2 km, it has been shown that its formation for more than 100 Ma has been caused by combination of internal and external factors. The latter comprise favorable metallogenic specialization of the region, injection of intrusive bodies bearing the necessary stock of energy, and periodic pulses of tectonic reactivation. The internal factors of self-development involve evolutionary processes, which occur in host rocks at the consecutive stages of prograde and retrograde metamorphism giving rise to alteration of rocks in consistence with physical and chemical laws at variable temperature and degree of system opening.