The Relationship between Global Volcanic Activity and Variations in the Velocity of Earth’s Rotation

Doklady Earth Sciences - Analysis of observations of the Earth’s rotational velocity and volcanic activity of the planet from 1720 until 2015 suggests that higher volcanic activity temporally...     

An iterative method for simultaneously computing the synthesis of light and heavy elements

We propose an iterative algorithm for computing the synthesis of heavy elements through the rapid capture of neutrons (r-process) and, at sufficiently high temperatures, protons by simultaneously using two distinct computer codes. One of the codes describes the kinetics of nuclear reactions between light and intermediate chemical elements, which are the source of free neutrons and protons used by the second code to synthesize heavy elements from seed nuclides (isotopes near the iron peak of the cosmic abundance curve). The two codes interact through the neutron and proton reaction channels. We demonstrate the efficiency of our method with an example of the nucleosynthesis in a supernova’s helium shell triggered by the evaporation of neutrons and protons from α particles exposed to the neutrino flux from a collapsing stellar core. In this case, three or four iterations are enough to obtain an almost exact self-consistent solution.     

Diurnal variations of temperature as a cause of periodic variations of high-frequency geoacoustic emission

Investigated is the periodic component of geoacoustic emission within the frequency band from 2.0 to 6.5 kHz registered by the piezoceramic hydrophone installed near the bottom of Lake Mikizha in the Kamchatka Peninsula. It is revealed that the variation period is 24 hours and the maximum variation is observed in summer, when the average daily air temperature is above 10°C. In that period the close connection is revealed between the series of air temperature and geoacoustic emission. Taking into account the similar results of measurements of the ground surface slope at the observation site, the most probable reason for the diurnal variations of high-frequency geoacoustic emission is the deformation of near-surface sedimentary rocks caused by diurnal variations of temperature.     

Quality Appraisal of Surface Waters on Fennoscandian Territory

Widely applied bioindication methods are analyzed based on the survey data of 1980–1996 for over 400 lakes and 300 watercourses in the northeastern Fennoscandia known to experience anthropogenic impact (toxification, acidification, eutrophication, and thermofication). Representative results of hydrobiological analysis of the quality of surface waters in areas with mixed toxic pollution (or anthropogenic acidification) may be obtained if methods are applied, different from the bioindication methods that are now accepted as standard for Russia, along with methods of biotesting natural waters. The saprotoxibity index, Kola biotic index, acidification estimation scale, biotesting methods were developed and adapted to regional conditions.     

3,4-benzopyrene and perylene in mussels, Mytilus sp., from the Laguna Veneta,North-East Italy

From July, 1975 to November, 1976 mussels from the Laguna Veneta, north-east Italy, and the adjacent Adriatic Sea were collected bimonthly at ten stations and analysed for 3,4-benzopyrene (BaP) and perylene (Pe) content. Mean concentrations were in the range 12·0–135·1 μg/kg dry weight for BaP and 1·5–16·9 μg/kg for Pe, but values as high as 327 μg/kg for BaP and 71 μg/kg for Pe have been measured. The distribution of BaP and Pe closely matches previous results on petroleum hydrocarbon contamination in mussels from this area and indicates that the major portion of BaP and Pe in these bivalves is due principally to human activities.     

Searches for very high energy gamma rays from blazars with CANGAROO-III telescope in 2005-2009

We have searched for very high energy (VHE) gamma rays from four blazars using the CANGAROO-III imaging atmospheric Cherenkov telescope. We report the results of the observations of H 2356-309, PKS 2155-304, PKS 0537-441, and 3C 279, performed from 2005 to 2009, applying a new analysis to suppress the effects of the position dependence of Cherenkov images in the field of view. No significant VHE gamma ray emission was detected from any of the four blazars. The GeV gamma-ray spectra of these objects were obtained by analyzing Fermi/LAT archival data. Wide range (radio to VHE gamma-ray bands) spectral energy distributions (SEDs) including CANGAROO-III upper limits, GeV gamma-ray spectra, and archival data, even though they are non-simultaneous, are discussed using a one-zone synchrotron self-Compton (SSC) model in combination with a external Compton (EC) radiation. The HBLs (H 2356-309 and PKS 2155-304) can be explained by a simple SSC model, and PKS 0537-441 and 3C 279 are well modeled by a combination of SSC and EC model. We find a consistency with the blazar sequence in terms of strength of magnetic field and component size.     

Propagation of the sea-surface temperature anomalies in the Tropical Atlantic

Summary The evolving modes of the sea-surface temperature (SST) in the Tropical Atlantic on the short interannual (IA) timescale were obtained by performing the extended empirical orthogonal function (EEOF) analyses on this variable separately for the 106-year (1871–1976) and 20-year (1881–1900; 1901–1920; 1921–1940; 1941–1960) periods. The equatorial and inter-hemispheric patterns manifest in the first EEOF mode of each analysis as part of the short IA evolution of the SST anomalies in the Tropical Atlantic. Another outstanding feature of the first EEOF mode of each analysis concerns the propagations of the SST anomalies in the meridional direction within the 20°N–20°S band and in the zonal direction in the sector 40°W–20°W. For all analyses, the SST anomalies propagate northward from the equator to 15°N and southward from 20°N to 15°N, with the same sign anomalies merging approximately at 15°N. On the other hand, the SST anomalies propagate westward in the sector 40°W–20°W with a propagation rate close to that of the phase speed of the fastest baroclinic Rossby wave in the ocean. So, the observed propagations of the SST anomalies in the 20°N–20°S band might result from the combined effect of the surface oceanic currents in this band and the baroclinic Rossby waves in the ocean.     

Study of the dependence of the star formation rate in the nuclear regions of 39 Kazarian galaxies on their integral parameters

A statistical study of the dependence of the star formation rate in the nuclear regions of 39 Kazarian galaxies on the integral parameters of these galaxies is carried out on the basis of spectra from SDSS DR6. The value of SFR/kpc² for our sample lies in the range 0.013÷2.04M _⨀ year⁻¹kpc⁻² (with the maximum value of 2.04 corresponding to the Kaz 98 (merger)). It is found that the surface density of the rate of star formation correlates positively with the bar structure parameter and EW(Hα), and that, for spiral galaxies of early morphological types, SFR/kpc² is greater than for the later types. It is shown that the color B-R for the galaxies and the color (u − g) _nucl for the nuclear region correlate positively with the total absorption A(Hα) in the Ha line for the nuclear region. The average value of A(Hα) for our samples is found to be A(Hα)=1.3±0.09 magnitudes. Translated from Astrofizika, Vol. 52, No. 2, pp. 211–224 (May 2009).     

Solar Microwave Bursts from Electron Populations with a 'Broken’ Energy Spectrum

Usually the gyrosynchrotron emission of microwave bursts from electron populations with a power-law (PL) energy distribution has been considered under the assumption that the spectral index of the distribution is constant over a wide range of energies. Meanwhile, there is strong evidence, in particular from hard X-ray and -ray, but also from cm/mm wavelength radio observations, that in many solar flare events the spectrum of the emitting electrons is characterized by a significant hardening at energies above 100–500 keV. We present some examples of calculated microwave burst spectra at cm/mm wavelengths taking into account the above evidence. It is shown that a break in the energy spectrum of the PL electrons can indeed result in a spectral hardening sometimes observed in microwave bursts at frequencies above 10–30 GHz.     

Quasi-sinusoidal oscillations of the angular velocity of pulsars

We study the oscillations of the angular velocity of pulsars, obtaining an equation for the angular velocity and its derivative taking account of the curvature of vortices. We show that this equation has a quasisinusoidal solution and find the period of these oscillations. We show that the estimates for the value of the periods for various models of neutron stars give quantities of the order of tens of days, which is in agreement with the observations of the quasi-periodic oscillations and fluctuations of the angular velocity of pulsars.Translated fromAstrofizika, Vol. 38, No. 2, 1995.