Cosmological scalar fields that mimic the ΛCDM\Lambda CDM cosmological model

We look for cosmologies with a scalar field (dark energy without cosmological constant), which mimic the standard $\Lambda CDM$ cosmological model yielding exactly the same large-scale geometry described by the evolution of the Hubble parameter (i.e. photometric distance and angular diameter distance as functions on $z$). Asymptotic behavior of the field solutions is studied in the case of spatially flat Universe with pressureless matter and separable scalar field Lagrangians (power-law kinetic term + power-law potential). Exact analytic solutions are found in some special cases. A number of models have the field solutions with infinite behavior in the past or even singular behavior at finite redshifts. We point out that introduction of the cosmological scalar field involves some degeneracy leading to lower precision in determination of $\Omega_m$. To remove this degeneracy additional information is needed beyond the data on large-scale geometry.Comment: VIII International Conference "Relativistic Astrophysics, Gravitation and Cosmology": May 21-23, 2008, Kyiv, Ukrain

Realization of the Vilnius photometric system for CCD-observations of selected sky areas at the Andrushivka Astronomical Observatory

We describe a set of glass UPXYZVS filters of the Vilnius photometric system of the Andrushivka Astronomical Observatory in Zhytomyr Region (Ukraine) [7]. They are installed at the Zeiss-600 Cassegrain reflector together with the 15-bit 1024×1024 CCD-camera S1C-017. The response curves of instrumental photometric systems are presented and a comparison of them with a standard system are analysed. Test observations in the Vilnius system of the star cluster IC 4665 with the Andrushivka filters were carried out in May–June 2003. The MIDAS/ROMAFOT and ASTROIMAGE software is adapted for digital processing of CCD-images of stellar fields. Comprehensive ground-based observations are being planned to design a catalogue of primary UPXYZVS CCD-standards in selected areas of the sky where are with radio sources, globular and open clusters, etc

Comamonas testosteroni strain TI as a potential base for a microbial sensor detecting surfactants

Strain Comamonas testosteroni TI, capable of degrading the nonionic surfactant (NIS) nonylphenolethoxylate (OP-10), was used for constructing a pilot cellular biosensor. The lower NIS detection limit for the biosensor was 0.25 mg/l. We studied the substrate specificity of the biosensor with respect to a wide range of organic compounds: surfactants, polyaromatic compounds (PAC), carbohydrates, alcohols, etc. It was shown that the biosensor based on Comamonas testosteroni TI did not respond to glucose, which was an advantage over the formerly described biosensor based on Pseudomonas rathonis T. The amplitude of the sensor response remained stable for 10 days

Evaluation of substrate specificity of biosensor models based on strains degrading polycyclic aromatic compounds

Models of microbial biosensors based on 11 strains of degraders of surface-active substances (SASS) and polycyclic aromatic hydrocarbons (PAHs) were studied. Substrate specificity, sensitivity, and stability of biosensor models were comparatively evaluated

Correlation function of quasars in real and redshift space from the Sloan Digital Sky Survey Data Release 7

We analyze the quasar two-point correlation function (2pCF) within the redshift interval $0.8<z<2.2$ using a sample of 52303 quasars selected from the recent 7th Data Release of the Sloan Digital Sky Survey. Our approach to 2pCF uses a concept of locally Lorentz (Fermi) frame for determination of the distance between objects and permutation method of the random catalogue generation. Assuming the spatially flat cosmological model with given $\Omega_{\Lambda}=0.726$, we found that the real-space 2pCF is fitted well with the power-low model within the distance range $1<\sigma<35$ $h^{-1}$ Mpc with the correlation length $r_{0}=5.85\pm0.33$ $h^{-1}$ Mpc and the slope $\gamma=1.87\pm0.07$. The redshift-space 2pCF is approximated with $s_{0}=6.43\pm0.63$ $h^{-1}$ Mpc and $\gamma=1.21\pm0.24$ for $1<s<10$ $h^{-1}$ Mpc, and $s_{0}=7.37\pm0.81$ $h^{-1}$ Mpc and $\gamma=1.90\pm0.24$ for $1010\,h^{-1}$ Mpc the parameter describing the large-scale infall to density inhomogeneities is $\beta=0.63\pm0.10$ with the linear bias $b=1.44\pm0.22$ that marginally (within 2$\sigma$) agrees with the linear theory of cosmological perturbations. We discuss possibilities to obtain a statistical estimate of the random component of quasars velocities (different from the large-scale infall). We note rather slight dependence of quasars velocity dispersion upon the 2pCF parameters in the region $r<2$ Mpc.Comment: 15 pages, 17 figures, online published in MNRAS; final version to match the published versio

Gravitational Ionization: A Chaotic Net in the Kepler System

The long term nonlinear dynamics of a Keplerian binary system under the combined influences of gravitational radiation damping and external tidal perturbations is analyzed. Gravitational radiation reaction leads the binary system towards eventual collapse, while the external periodic perturbations could lead to the ionization of the system via Arnold diffusion. When these two opposing tendencies nearly balance each other, interesting chaotic behavior occurs that is briefly studied in this paper. It is possible to show that periodic orbits can exist in this system for sufficiently small damping. Moreover, we employ the method of averaging to investigate the phenomenon of capture into resonance.Comment: REVTEX Style, Submitte

Electrophoretic Mobility of Red Blood Cells and Micronucleus Test in Exfoliated Buccal Cells as Stress Intensity Markers

The purpose of this study was to investigate the electrophoretic mobility of red blood cells (RBCs), cytomorphological and cytogenetical indices in exfoliated buccal epithelial cells of rats during the development of stress reaction. Experiments were carried out on 60 white non-pedigree pubescent rats weighing 180-220g. Both the single and the repeated adrenalin injections provoked a decrease in the level of the RBC electrophoretic mobility. With a single adrenalin injection, the changes in RBC electrophoretic mobility are not so abrupt, with the subsequent development of the adaptive response and reparation of cytogenetic damage. With repeated adrenalin injections, the changes in RBC electrophoretic mobility are abrupt, and the number of pathological epithelial cells increases

Basal Respiration as a Proxy to Understand Spatial Trends in CO2 Emissions in the Moscow Region

Soil respiration (Rs) is an important terrestrial CO2 efflux and receives significant attention at different scale levels. However, the sampling density is limited and global Rs databases are biased towards natural ecosystems. Urbanization is among the most important current land-use trends and its role will likely grow in the future. Urban soils store considerable amount of carbon and are very heterogeneous and dynamic, which affects Rs. Our understanding of the Rs spatial variability is limited, especially for the regions with heterogeneous bioclimatic conditions and high urbanization level. The methodological constraints of direct Rs measurements in the field limit the number of observations. As an alternative approach to approximate the spatial variability of Rs, we used basal respiration (BR) as an indirect measurement. We implemented digital soil mapping technique to map BR as a proxy of Rs in a heterogeneous and urbanized Moscow Region. Topsoil and subsoils BR maps were developed for the region and spatial variability per land-use and soil type was analyzed. BR averaged for the urban areas was lower than in forests and meadows, however, urban areas became the hotspots of BR’s spatial variability in the region. Considerable contribution of subsoil layers to the total BR was also found with the maximal 30% contribution in urban soils. Although the absolute levels of respiration remained uncertain, the spatial patterns of BR are likely to correspond well with Rs patterns, determined by soil type, land use and allocation of urban areas