Segmentation of the Izu-Bonin and Mariana slabs based on the analysis of the Benioff seismicity distribution and regional tomography results

We present a new model of P and S velocity anomalies in the mantle down to a depth of 1300 km beneath the Izu-Bonin and Mariana (IBM) arcs. This model is derived based on tomographic inversion of global travel time data from the revised ISC catalogue. The results of inversion are thoroughly verified using a series of different tests. The obtained model is generally consistent with previous studies by different authors. We also present the distribution of relocated deep events projected to the vertical surface along the IBM arc system. Unexpectedly, the seismicity forms elongated vertical clusters instead of horizontal zones indicating phase transitions in the slab. We propose that these vertical seismicity zones mark zones of intense deformation and boundaries between semi-autonomous segments of the subducting plate. The P and S seismic tomography models consistently display the slab as prominent high-velocity anomalies coinciding with the distribution of deep seismicity. We can distinguish at least four segments which subduct differently. The northernmost segment of the Izu-Bonin arc has the gentlest angle of dipping which is explained by backward displacement of the trench. In the second segment, the trench stayed at the same location, and we observe the accumulation of the slab material in the transition zone and its further descending to the lower mantle. In the third segment, the trench is moving forward causing the steepening of the slab. Finally, for the Mariana segment, despite the backward displacement of the arc, the subducting slab is nearly vertical. Between the Izu-Bonin and Mariana arcs we clearly observe a gap which can be traced down to about 400 km in depth. Based on joint consideration of the tomography results and the seismicity distribution, we propose two different scenarios of the subduction evolution in the IBM zone during the recent time, depending on the reference frame of plate displacements. In the first case, we consider the movements in respect to the Philippine Plate, and explain the different styles of the subduction by the relative backward and forward migrations of the trench. In the second case, all the elements of the subduction system move westward in respect to the stable Asia. Different subduction styles are explained by the "anchoring" of selected segments of the slab, different physical properties of the subducting plate and the existence of buoyant rigid blocks related to sea mount and igneous provinces

The theory of a "staphylococcus superantigen" in chronic rhinosinusitis with nasal polyps: myth or reality?

OBJECTIVE: The aim of our study was to search for evidence of a "staphylococcus superantigen" in chronic rhinosinusitis with nasal polyps. PATIENTS AND METHODS: Sixty-nine patients with chronic rhinosinusitis with nasal polyps and 45 healthy controls were included in the study. All patients in the study and control groups underwent bacteriological and immunological examination on nasal smear samples. Total IgE and the following cytokines were tested in all patients: tumor necrosis factor (TNF), interleukin-1 (IL1), interleukin-6 (IL6), interleukin-8 (IL8). RESULTS: The concentration of bacteria in the nasal cavity was much higher in patients in the study group compared to those in the control group, mainly due to staphylococci. In species identification of staphylococci, bacteria most represented were S. aureus and S. epidermidis. The greater the concentration of S. aureus, the lower the level of IgE. Proinflam-matory cytokines were uniformly increased in patients with nasal polyps. The level of IgE was maximal in patients with chronic rhinosinusitis with nasal polyps with a poor growth of culture and minimal in patients with abundant growth, suggesting that in the latter the effect of eosinophilic inflammation on the disease was reduced, and conversely, the activity of eosinophilic inflammation was maximal with a poor seeding of the nasal cavity. CONCLUSIONS: Although this study has some limits, our findings do not support the theory of a staphylococcus superantigen in which the IgE level and eosinophilic inflammation should increase with increasing activity of Staphylococcus aureus. Further research supported by a larger sample of patients is required to better delineate the role of a staphylococcus superantigen in the pathogenesis of patients with chronic rhinosinusitis with nasal polyps

Gramella portivictoriae sp nov, a novel member of the family Flavobacteriaceae isolated from marine sediment (vol 55, pg 2497, 2005)

A yellow-pigmented, Gram-negative, slowly gliding, rod-shaped, strictly aerobic bacterium (UST040801-001T) was isolated from marine sediment. The DNA G+C content was 39?9 mol%. The predominant fatty acids were a15 : 0, i15 : 0, i15 : 0 3-OH, i17 : 1v9c, i17 : 0 3-OH and summed feature 3, comprising i15 : 0 2-OH and/or 16 : 1v7c (altogether representing 76?2% of the total). MK-6 was the only respiratory quinone. Flexirubin-type pigments were not produced. Phylogenetic analysis based on 16S rRNA gene sequences indicated that Gramella echinicola KMM 6050T (the only species in the genus) was the closest relative of UST040801-001T, sharing 98?0% sequence similarity. The DNA–DNA relatedness between UST040801-001T and Gramella echinicola KMM 6050T was 13 %. Strain UST040801-001T can be distinguished from G. echinicola by means of 11 phenotypic traits. The results of molecular and phenotypic analyses suggested that UST040801-001T represents a novel species of Gramella. The name Gramella portivictoriae sp. nov. is proposed for this bacterium, with UST040801-001T (=NRRL 41137T=JCM 13192T) as the type strain

Living on the edge: Biofilms developing in oscillating environmental conditions

For the first time, the densities and diversity of microorganisms developed on ocean gliders were investigated using flow cytometry and Illumina MiSeq sequencing of 16S and 18S rRNA genes. Ocean gliders are autonomous buoyancy-driven underwater vehicles, equipped with sensors continuously recording physical, chemical, and biological parameters. Microbial biofilms were investigated on unprotected parts of the glider and surfaces coated with base, biocidal and chitosan paints. Biofilms on the glider were exposed to periodical oscillations of salinity, oxygen, temperature, pressure, depth and light, due to periodic ascending and descending of the vehicle. Among the unprotected surfaces, the highest microbial abundance was observed on the bottom of the glider’s body, while the lowest density was recorded on the glider’s nose. Antifouling paints had the lowest densities of microorganisms. Multidimensional analysis showed that the microbial communities formed on unprotected parts of the glider were significantly different from those on biocidal paint and in seawater

Description of Fabibacter halotolerans gen. nov., and reclassification of [Marinicola] seohaensis as Roseivirga seahaensis comb. nov.

Bacterial strains UST030701-097T and UST030701-084T were isolated from a marine sponge in the Bahamas. Both strains were pink-pigmented, Gram-negative, strictly aerobic and chemo-organotrophic. Cells of strain UST030701-097T were short, curved rods with fast-gliding motility, whereas those of strain UST030701-084T were straight rods with a less rapid gliding motion. The two strains had MK-7 as the major respiratory quinone and did not produce flexirubin-type pigments. The DNA G+C contents of strains UST030701-097T and UST030701-084T were 42.5 and 43.7 mol%, respectively. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the two strains belonged to the family 'Flexibacteraceae' of the phylum Bacteroidetes. 16S rRNA gene sequence similarity between strains UST030701-097T and UST030701-084T was 95.0 %; their closest relative was [Marinicola] seohaensis, with 93.3 % and 96.0 % sequence similarity, respectively. Phylogenetic tree topology indicated that the two strains belonged to the same lineage, but were on separate branches. Whilst strain UST030701-084T and [Marinicola] seohaensis were found on one branch, strain UST030701-097T was in another branch that had no species with validly published names. Based on the polyphasic taxonomic data obtained in the present study, we propose that strain UST030701-097T represents a novel genus and that strain UST030701-084T represents a novel species in the phylum Bacteroidetes. The genus Fabibacter gen. nov. is proposed, with strain UST030701-097T (=NRRL B-41220T=JCM 13334T) as the type strain of the type species, Fabibacter halotolerans sp. nov. Strain UST030701-084T (=NRRL B-41219T=JCM 13337T) is proposed as the type strain of Roseivirga spongicola sp. nov. In an earlier study, it was suggested that the genus Marinicola is a later heterotypic synonym of the genus Roseivirga. However, a formal proposal to reclassify [Marinicola] seohaensis, the only member of the genus Marinicola, has not yet been made. The results of phylogenetic analyses in this study support the reclassification of [Marinicola] seohaensis as Roseivirga seohaensis comb. nov

Stenothermobacter spongiae gen. nov., sp. nov., a novel member of the family Flavobacteriaceae isolated from a marine sponge in the Bahamas, and emended description of Nonlabens tegetincola

A bacterial strain, UST030701-156T, was isolated from a marine sponge in the Bahamas. Strain UST030701-156T was orange-pigmented, Gram-negative, rod-shaped with tapered ends, slowly motile by gliding and strictly aerobic. The predominant fatty acids were a15 : 0, i15 : 0, i15 : 0 3-OH, i17 : 0 3-OH, i17 : 1ω9c and summed feature 3, comprising i15 : 0 2-OH and/or 16 : 1ω7c. MK-6 was the only respiratory quinone. Flexirubin-type pigments were not produced. Phylogenetic analysis based on 16S rRNA gene sequences placed UST030701-156T within a distinct lineage in the family Flavobacteriaceae, with 93·3 % sequence similarity to the nearest neighbour, Nonlabens tegetincola. The DNA G+C content of UST030701-156T was 41·0 mol% and was much higher than that of N. tegetincola (33·6 mol%). Strain UST030701-156T can be distinguished from other members of the Flavobacteriaceae by means of a number of chemotaxonomic and phenotypic characteristics. It is proposed, therefore, that UST030701-156T represents a novel taxon designated Stenothermobacter spongiae gen. nov., sp. nov. The type strain is UST030701-156T (=NRRL B-41138T=JCM 13191T). Carbon-source utilization by N. tegetincola was re-examined and an emended description is therefore included

Studies of concentration and temperature dependencies of precipitation kinetics in iron-copper alloys using kinetic monte carlo and stochastic statistical simulations

The earlier-developed ab initio model and the kinetic Monte Carlo method (KMCM) are used to simulate precipitation in a number of iron-copper alloys with different copper concentrations x and temperatures T. The same simulations are also made using the improved version of the earlier-suggested stochastic statistical method (SSM). The results obtained enable us to make a number of general conclusions about the dependencies of the decomposition kinetics in Fe-Cu alloys on x and T. We also show that the SSM describes the precipitation kinetics in a fair agreement with the KMCM, and employing the SSM in conjunction with the KMCM enables us to extend the KMC simulations to the longer evolution times. The results of simulations seem to agree with available experimental data for Fe-Cu alloys within statistical errors of simulations and the scatter of experimental results. Comparison of results of simulations to experiments for some multicomponent Fe-Cu-based alloys enables us to make certain conclusions about the influence of alloying elements in these alloys on the precipitation kinetics at different stages of evolution.Comment: 18 pages, 17 postscript figures, LaTe

Testing neutrino magnetic moment in ionization of atoms by neutrino impact

The atomic ionization processes induced by scattering of neutrinos play key roles in the experimental searches for a neutrino magnetic moment. Current experiments with reactor (anti)neutrinos employ germanium detectors having energy threshold comparable to typical binding energies of atomic electrons, which fact must be taken into account in the interpretation of the data. Our theoretical analysis shows that the so-called stepping approximation to the neutrino-impact ionization is well applicable for the lowest bound Coulomb states, and it becomes exact in the semiclassical limit. Numerical evidence is presented using the Thomas-Fermi model for the germanium atom.Comment: 5 pages, 1 figur