5,045 research outputs found

    Evolution of massive fields around a black hole in Horava gravity

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    We study the evolution of massive scalar field in the spacetime geometry of Kehagias-Sfetsos(KS) black hole in deformed Horava-Lifshitz(HL) gravity by numerical analysis. We find that the signature of HL theory is encoded in the quasinormal mode(QNM) phase of the evolution of field. The QNM phase in the evolution process lasts for a longer time in HL theory. QNMs involved in the evolution of massive field are calculated and find that they have a higher oscillation frequency and a lower damping rate than the Schwarzschild spacetime case. We also study the relaxation of field in the intermediate and asymptotic range and verified that behaviors of field in these phases are independent of the HL parameter and is identical to the Schwarzschild case.Comment: The article was fully rewritten, references added, accepted to GR

    Collection and estimation of zooplankton

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    Zooplankters are the diverse, delicate and often very beautiful assemblages of animals that drift in the waters of the world oceans. The name zooplankton is derived from the Greek: Zoon, animal; planktos, wandering. They play a key role in the marine food web by transferring the organic energy produced by the unicellular algae to higher trophic levels such as pelagic stocks. Because of their critical role as food source for larval and juvenile fish, the dynamics of zooplankton populations, their reproductive cycles, growth and survival rates are all important factors influencing recruitment of fish stocks and thereby the magnitude of fishery. Majority of them are microscopic, unicellular or multicellular forms with size ranging from a few microns to a millimeter or more. In addition to size variations, there are differences in morphological features and taxonomic position. The zooplankton plays an important role to study the faunal biodiversity of aquatic ecosystems

    Thermodynamic Geometry of Reissener-Nordstr\"{o}m-de Sitter black hole and its extremal case

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    We study the thermodynamics and the different thermodynamic geometric methods of Reissener-Nordstr\"{o}m-de Sitter black hole and its extremal case, which is similar to the de Sitter black hole coupled to a scalar field, rather called an MTZ black hole. While studying the thermodynamics of the systems, we could find some abnormalities. In both cases, the thermodynamic geometric methods could give the correct explanation for the all abnormal thermodynamic behaviors in the system.Comment: 11 pages, 8 figures and accepted for publication in Gen. Relativ. Gravi

    Phytoplankton - collection, estimation, classification and diversity

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    In the existing sampling methodology, the interest is to estimate gear-wise, species-wise landings for the state in a month, fishing effort according to different types of fishing boats and also in terms of man hours. The analysis is carried out at CMFRI headquarters. Before the data is processed for analysis it will be ensured that the data collection is made as per the approved schedule, by checking the appropriate proforma. The responsibilities and functions of staff at the headquarters are data coding, estimation and database management. The data analysis is computerised and estimates are made using the software developed by the Fishery Resources Assessment Division of the Institute. The processed data are again counter- checked for errors. When discrepancies are detected, the estimation procedure is scrutinised in detail

    Pelagic sharks by-catch in the tuna longline fishery of the Indian EEZ

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    Several species of pelagic and oceanic sharks are caught by the tuna longliners of FSI while surveying the oceanic tuna resources in the Indian EEZ. Though the sharks are not targeted species in tuna longlining, they constitute a major share of the catches. The sharks hooked could be, therefore, treated as by- catches or incidental catches of the tuna longline fisher
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