17,756 research outputs found

    Effect of spectral modification of ρ\rho on shear viscosity of a pion gas

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    We evaluate the shear viscosity of a pion gas in the relativistic kinetic theory approach. The in-medium propagator of the ρ\rho meson at finite temperature is used to evaluate the ππ\pi-\pi scattering amplitude in the medium. The real and imaginary parts of the self-energy calculated from one-loop diagrams are seen to have noticeable effects on the scattering cross-section. The consequences on temperature dependence of the shear viscosity evaluated in the Chapman-Enskog and relaxation time approximations are studied

    Polylithiated (OLi2) functionalized graphane as a potential hydrogen storage material

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    Hydrogen storage capacity, stability, bonding mechanism and the electronic structure of polylithiated molecules (OLi2) functionalized graphane (CH) has been studied by means of first principle density functional theory (DFT). Molecular dynamics (MD) have confirmed the stability, while Bader charge analysis describe the bonding mechanism of OLi2 with CH. The binding energy of OLi2 on CH sheet has been found to be large enough to ensure its uniform distribution without any clustering. It has been found that each OLi2 unit can adsorb up to six H2 molecules resulting into a storage capacity of 12.90 wt% with adsorption energies within the range of practical H2 storage application.Comment: 11 pages, 4 figures, 1 table, Phys. Chem. Chem. Phys. (submitted

    Non-local space-time supersymmetry on the lattice

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    We show that several well-known one-dimensional quantum systems possess a hidden nonlocal supersymmetry. The simplest example is the open XXZ spin chain with \Delta=-1/2. We use the supersymmetry to place lower bounds on the ground state energy with various boundary conditions. For an odd number of sites in the periodic chain, and with a particular boundary magnetic field in the open chain, we can derive the ground state energy exactly. The supersymmetry thus explains why it is possible to solve the Bethe equations for the ground state in these cases. We also show that a similar space-time supersymmetry holds for the t-J model at its integrable ferromagnetic point, where the space-time supersymmetry and the Hamiltonian it yields coexist with a global u(1|2) graded Lie algebra symmetry. Possible generalizations to other algebras are discussed.Comment: 12 page

    EChOSim: The Exoplanet Characterisation Observatory software simulator

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    EChOSim is the end-to-end time-domain simulator of the Exoplanet Characterisation Observatory (EChO) space mission. EChOSim has been developed to assess the capability EChO has to detect and characterize the atmospheres of transiting exoplanets, and through this revolutionize the knowledge we have of the Milky Way and of our place in the Galaxy. Here we discuss the details of the EChOSim implementation and describe the models used to represent the instrument and to simulate the detection. Software simulators have assumed a central role in the design of new instrumentation and in assessing the level of systematics affecting the measurements of existing experiments. Thanks to its high modularity, EChOSim can simulate basic aspects of several existing and proposed spectrometers for exoplanet transits, including instruments on the Hubble Space Telescope and Spitzer, or ground-based and balloon borne experiments. A discussion of different uses of EChOSim is given, including examples of simulations performed to assess the EChO mission

    Physiological responses of sub1A QTL under induced dehydration stress for varying days in rice

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    This study analysed the rice genotype with sub1A quantitative trait loci that may interact with ongoing exposure of dehydration. cv. Swarna Sub1 had more nutrients efficiency with increased membrane permeability than cv. Swarna. sub1A QTL with its expression to water / osmotic deficit, however, indirectly to impede the oxidative stress under dehydration might help cv. Swarna Sub1. At maximum dehydration cv. Swarna Sub1 had 1.12 fold excess electrolyte leakages than cv. Swarna under dehydration. cv. Swarna Sub1 had better Nicotinamide adenine dinucleotide phosphate-malic enzyme activity to secure carbon dioxide exchange. A proportional increase in enzyme activity all through dehydration stress maximize under light in cv. Swarna Sub1. At maximum dehydration cv. Swarna Sub1 at saturating substrate concentration was increased by 1.12 fold than other cultivar. The ratio of glutathione (GSH:GSSG) more depleted in cv. Swarna Sub1 through the dehydration period. cv. Swarna could be more promising to retrieve the activity by 1.80 fold than cv. Swarna Sub1 under maximum dehydration. Dehydroascorbate reductase activity was also maintained in cv. Swarna with 1.20 fold ahead than cv. Swarna Sub1 under same condition. As a biomarker of oxidative stress cv. Swarna Sub1 appeared to be less sensitive with the loss of protein oxidation, however, recorded with 25% less carbonyl content than cv. Swarna. Both the genotypes had scored a significant sensitivity with tissue specific distribution for reactive oxygen species as detected by histochemical assay

    On the Thermodynamic Geometry of BTZ Black Holes

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    We investigate the Ruppeiner geometry of the thermodynamic state space of a general class of BTZ black holes. It is shown that the thermodynamic geometry is flat for both the rotating BTZ and the BTZ Chern Simons black holes in the canonical ensemble. We further investigate the inclusion of thermal fluctuations to the canonical entropy of the BTZ Chern Simons black holes and show that the leading logartithmic correction due to Carlip is reproduced. We establish that the inclusion of thermal fluctuations induces a non zero scalar curvature to the thermodynamic geometry.Comment: 1+17 pages, LaTeX, 4 eps figure

    Abundance and Occurrence of Phosphate Solubilizing Bacteria and Phosphatase in Sediment of Hooghly Estuary, North East Coast of Bay of Bengal, India

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    The abundance and occurrence of a special group of bacteria, capable of solubilizing or mobilizing insoluble phosphates were studied in estuarine environment, especially in sediments. The possible role of various factors of the sediments in maintaining the phosphate availability in the overlying water was described. The phosphatase activity was recorded in all samples irrespective of salinity variations. Total number of bacteria showed higher value in lower salinity. The total phosphate content in soil showed positive correlation with the phosphatase activity ( r = 0.890; P-Value = 0.000; n-=15). Clayey sediment contents more phosphate solubilizing bacteria and phosphatase than sandy sediment in a tropical estuarine region of River Hooghly
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