Random Sierpinski network with scale-free small-world and modular structure

In this paper, we define a stochastic Sierpinski gasket, on the basis of which we construct a network called random Sierpinski network (RSN). We investigate analytically or numerically the statistical characteristics of RSN. The obtained results reveal that the properties of RSN is particularly rich, it is simultaneously scale-free, small-world, uncorrelated, modular, and maximal planar. All obtained analytical predictions are successfully contrasted with extensive numerical simulations. Our network representation method could be applied to study the complexity of some real systems in biological and information fields.Comment: 7 pages, 9 figures; final version accepted for publication in EPJ

Aerosol particles at a high-altitude site on the Southeast Tibetan Plateau, China: Implications for pollution transport from South Asia

      Bulk aerosol samples were collected from 16 July 2008 to 26 July 2009 at Lulang, a high-altitude (>3300m above sea level) site on the southeast Tibetan Plateau (TP); objectives were to determine chemical characteristics of the aerosol and identify its major sources. We report aerosol (total suspended particulate, TSP) mass levels and the concentrations of selected elements, carbonaceous species, and water-soluble inorganic ions. Significant buildup of aerosol mass and chemical species (organic carbon, element carbon, nitrate, and sulfate) occurred during the premonsoon, while lower concentrations were observed during the monsoon. Seasonal variations in aerosol and chemical species were driven by precipitation scavenging and atmospheric circulation. Two kinds of high-aerosol episodes were observed: one was enriched with dust indicators (Fe and Ca2+), and the other was enhanced with organic and elemental carbon (OC and EC), SO42−, NO3−, and Fe. The TSP loadings during the latter were 3 to 6 times those on normal days. The greatest aerosol optical depths (National Centers for Environmental Protection/National Center for Atmospheric Research reanalysis) occurred upwind, in eastern India and Bangladesh, and trajectory analysis indicates that air pollutants were transported from the southwest. Northwesterly winds brought high levels of natural emissions (Fe, Ca2+) and low levels of pollutants (SO42−, NO3−, K+, and EC); this was consistent with high aerosol optical depths over the western deserts and Gobi. Our work provides evidence that both geological and pollution aerosols from surrounding regions impact the aerosol population of the TP

Charmless Bs→PP,PV,VVB_s\to PP, PV, VV Decays Based on the six-quark Effective Hamiltonian with Strong Phase Effects II

We provide a systematic study of charmless $B_s \to PP, PV, VV$ decays ($P$ and $V$ denote pseudoscalar and vector mesons, respectively) based on an approximate six-quark operator effective Hamiltonian from QCD. The calculation of the relevant hard-scattering kernels is carried out, the resulting transition form factors are consistent with the results of QCD sum rule calculations. By taking into account important classes of power corrections involving "chirally-enhanced" terms and the vertex corrections as well as weak annihilation contributions with non-trivial strong phase, we present predictions for the branching ratios and CP asymmetries of $B_s$ decays into PP, PV and VV final states, and also for the corresponding polarization observables in VV final states. It is found that the weak annihilation contributions with non-trivial strong phase have remarkable effects on the observables in the color-suppressed and penguin-dominated decay modes. In addition, we discuss the SU(3) flavor symmetry and show that the symmetry relations are generally respected

Mutagenesis of intact parvovirus H-1 is expressed co-ordinately with enhanced reactivation of ultraviolet irradiated virus in human and rat cells treated with 2-nitronaphthofurans

The exposure of human or rat cells to non-toxic concentrations of two 2-nitronaphthofuran derivatives activated co-ordinately the transient expression of mutator and repair activities. These activities gave rise to both an increase in the mutagenesis (enhanced mutagenesis, EM) and survival (enhanced reactivation, ER) of unirradiated and u.v.-irradiated parvovirus H-1 used as respective probes. The kinetics of expression was the same for mutator and repair activities and for the two chemicals studied. The dose-responses of these activities were also parallel for a given chemical, but one of the furan derivatives exerted its inducing effect at concentrations 20-25 times lower than the other derivative. Both EM and ER were depressed by cycloheximide, an inhibitor of de novo protein synthesis. This is the first report which shows that chemicals can enhance the mutagenesis of undamaged DNA by activating the expression of mutator functions in mammalian, including human, cells. The ability of the two 2-nitronaphthofuran derivatives to trigger EM and ER was found to correlate with their reported mutagenicity in a conventional bacterial test system.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Ultraviolet-irradiated simian virus 40 activates a mutator function in rat cells under conditions preventing viral DNA replication

The UV-irradiated temperature-sensitive early SV40 mutant tsA209 is able to activate at the non-permissive temperature the expression of mutator and recovery functions in rat cells. Unirradiated SV40 activates these functions only to a low extent. The expression of these mutator and recovery functions in SV40-infected cells was detected using the single-stranded DNA parvovirus H-1 as a probe. Because early SV40 mutants are defective in the initiation of viral DNA synthesis at the non-permissive temperature, these results suggest that replication of UV-damaged DNA is not a prerequisite for the activation of mutator and recovery functions in mammalian cells. The expression of the mutator function is dose-dependent, i.e. the absolute number of UV-irradiated SV40 virions introduced per cell determines its level. Implications for the interpretation of mutation induction curves in the progeny of UV-irradiated SV40 in permissive host cells are discussed. © 1982 Masson, Paris.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Indirect induction of mutagenesis of intact parvovirus H-1 in mammalian cells treated with UV light or with UV-irradiated H-1 or simian virus 40

SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Mutagenesis at putative apurinic sites in alkylated single-stranded DNA of parvovirus H-1 propagated in human cells

The treatment of parvovirus H-1, a single-stranded DNA virus, with ethylnitrosourea immediately prior to infection of human cells, resulted in both virus mutagenesis and lethality (immediate hits). The incubation of treated virus, prior to inoculation, under conditions promoting the release of alkylated bases, slightly reduced the mutagenicity of ethylnitrosourea but significantly increased its killing effect (delayed hits). In untreated cells, the appearance of one apurinic/apyrimidinic site in viral DNA correlated with the formation of approximately one delayed lethal hit per virus. Cells which had been sublethally UV irradiated prior to infection, were able to overcome about 20% of the delayed lethal hits inflicted to ehthylnitrosourea-treated H-1. This UV-enhanced reactivation was accompanied by viral mutagenesis and was not observed for immediate lethal hits. Therefore, UV irradiation of human cells appears to trigger a conditioned recovery response which might alleviate a block to the replication of single-stranded DNA containing apurinic sites, allowing these noncoding lesions to direct mutagenesis. UV-irradiated cells also displayed a mutator phenotype towards untreated parvovirus H-1. In contrast, ethylnitrosourea failed to induce human cells to cause mutagenesis of undamaged viral DNA, although it enhanced their ability to reactivate damaged virus. © 1985.SCOPUS: ar.jinfo:eu-repo/semantics/publishe