20 research outputs found

    Tritonibacter horizontis gen. nov., sp. nov., a member of the rhodobacteraceae, isolated from the Deepwater Horizon oil spill

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    A heterotrophic, Gram-stain-negative, aerobic, sodium-requiring and motile bacterium was isolated from oil-contaminated surface water of the Gulf of Mexico during the Deepwater Horizon oil spill. Strain O3.65T showed highest 16S rRNA gene sequence similarity to Phaeobacter gallaeciensis BS107T and Phaeobacter inhibens T5T, both with 98.3%, respectively. Based on complete genome analysis, highest similarity was observed to species of the genus Ruegeria. Strain O3.65T exhibited a broad salinity, temperature and pH range of 0.5-10% NaCl, 4-45 °C and 5.5-9.0, respectively. The DNA G+C content of strain O3.65T was 61.5 mol%. The major respiratory lipoquinone was ubiquinone-10 (Q-10), the most dominant fatty acids (>1%) comprised 18: 1ω7c and 18: 1ω7c 11-methyl, 10: 0 3OH, 12: 1 3OH, 14: 1 3OH/3-oxo-14: 0, 16: 0, 16: 0 2OH, 18: 1 2OH and 12: 1. The polar lipid pattern indicated presence of phosphatidylcholine, phosphatidylglycerol, an unidentified aminolipid, two unidentified phospholipids and seven unidentified lipids. On Difco marine broth agar, strain O3.65T formed smooth, shiny white to beige and convex colonies with regular edges. Phylogenetic, phylogenomic and phenotypic differences revealed that strain O3.65T represents a new species of a novel genus within the family Rhodobacteraceae, for which we propose the name Tritonibacter horizontis gen. nov., sp. nov. The type strain of the type species is O3.65T (=DSM 101689T=LMG 29740T)

    Dynamics of interacting phantom and quintessence dark energies

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    We present models, in which phantom energy interacts with two different types of dark energies including variable modified Chaplygin gas (VMCG) and new modified Chaplygin gas (NMCG). We then construct potentials for these cases. It has been shown that the potential of the phantom field decreases from a higher value with the evolution of the Universe.Comment: 7 pages, 6 figures, accepted for publication in Astrophysics and Space Scienc

    Inflation at Low Scales: General Analysis and a Detailed Model

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    Models of inflationary cosmology based on spontaneous symmetry breaking typically suffer from the shortcoming that the symmetry breaking scale is driven to nearly the Planck scale by observational constraints. In this paper we investigate inflationary potentials in a general context, and show that this difficulty is characteristic only of potentials V(ϕ)V(\phi) dominated near their maxima by terms of order ϕ2\phi^2. We find that potentials dominated by terms of order ϕm\phi^m with \hbox{m>2m > 2} can satisfy observational constraints at an arbitrary symmetry breaking scale. Of particular interest, the spectral index of density fluctuations is shown to depend only on the order of the lowest non-vanishing derivative of V(ϕ)V(\phi) near the maximum. This result is illustrated in the context of a specific model, with a broken SO(3){\rm SO(3)} symmetry, in which the potential is generated by gauge boson loops.Comment: Submitted to Phys. Rev. D. 32 Pages, REVTeX. No figure

    Fractional Action Cosmology: Emergent, Logamediate, Intermediate, Power law Scenarios of the Universe and Generalized Second Law of Thermodynamics

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    In the framework of Fractional Action Cosmology (FAC), we study the generalized second law of thermodynamics for the Friedmann Universe enclosed by a boundary. We use the four well-known cosmic horizons as boundaries namely, apparent horizon, future event horizon, Hubble horizon and particle horizon. We construct the generalized second law (GSL) using and without using the first law of thermodynamics. To check the validity of GSL, we express the law in the form of four different scale factors namely emergent, logamediate, intermediate and power law. For Hubble, apparent and particle horizons, the GSL holds for emergent and logamediate expansions of the universe when we apply with and without using first law. For intermediate scenario, the GSL is valid for Hubble, apparent, particle horizons when we apply with and without first law. Also for intermediate scenario, the GSL is valid for event horizon when we apply first law but it breaks down without using first law. But for power law expansion, the GSL may be valid for some cases and breaks down otherwise.Comment: 24 pages, 32 figures, Accepted in Int. J. Theor. Phy

    Pangenomics of the marine bacterium Alteromonas macleodii

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    This study investigates multiple representatives of the marine bacterium Alteromonas macleodii for strain-specific abilities that shape ecological differentiation. For this purpose, several novel and publicly available A. macleodii strains were whole-genome sequenced and analyzed using a pangenomic approach. Supported by phenotypic evidence, this revealed niche adaptations related to iron acquisition, polysaccharide degradation, cellular communication and interaction with different phototrophic guilds

    From ethnography to theory: A programme and paradigm in the sociology of education

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    There is a shortage of well-developed and systematically tested theory in sociology, and in the sociology of education in particular. The studies of the effects of streaming and banding carried out by Hargreaves, Lacey and Ball provide one of the few examples of a powerful theory which has survived systematic testing. This sequence of studies provides the basis for a research programme extending beyond the field of education. At the same time, and more importantly, this body of research offers a paradigm for case study research designed to develop and test theory. In this way it helps to close the deplorable, and much lamented, gap between theory and empirical research

    Sorção de fósforo em função do teor inicial e de sistemas de manejo de solos

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    A relação entre o P sorvido/P solução do solo pode ser influenciada pelo teor de P previamente sorvido e pelos sistemas de manejo. Este trabalho teve o objetivo de avaliar as modificações na capacidade de sorção máxima (Pmax) e na constante relacionada com a energia de ligação de P com os colóides (k) da isoterma de Langmuir, provocadas (a) pela inclusão do teor de P previamente sorvido (Ppre) e (b) por sistemas de manejo de solos. Coletaram-se, em maio de 1997, amostras de solo (Latossolo Vermelho distroférrico típico, Latossolo Vermelho distrófico típico e Argissolo Vermelho distrófico típico), em três camadas (0-2,5, 2,5-7,5 e 7,5-17,5 cm), de três experimentos instalados a partir de 1979, envolvendo os sistemas plantio direto e cultivo convencional com diferentes sucessões de cultura. O solo foi equilibrado com oito concentrações de P em solução de CaCl2 0,001 mol L-1. Após a agitação por 16 h, avaliou-se a concentração de P no sobrenadante. Os dados de P-sorvido e P-solução foram ajustados à equação de Langmuir, obtendo-se a Pmax e a k, considerando ou não o Ppre. A inclusão do Ppre no modelo de Langmuir aumenta, em média, 2,9 vezes o valor da k e não afeta a Pmax, no LVdf, e aumenta em todas as camadas, no LVd, e na camada superficial, no PVd. A Pmax é pouco influenciada pelos métodos de preparo do solo, sucessões de culturas e camadas amostradas
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