537 research outputs found

    On Unitarity of Massive Gravity in Three Dimensions

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    We examine a unitarity of a particular higher-derivative extension of general relativity in three space-time dimensions, which has been recently shown to be equivalent to the Pauli-Fierz massive gravity at the linearized approximation level, and explore a possibility of generalizing the model to higher space-time dimensions. We find that the model in three dimensions is indeed unitary in the tree-level, but the corresponding model in higher dimensions is not so due to the appearance of non-unitary massless spin-2 modes.Comment: 10 pages, references adde

    Renormalizability of Massive Gravity in Three Dimensions

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    We discuss renormalizability of a recently established, massive gravity theory with particular higher derivative terms in three space-time dimensions. It is shown that this massive gravity is certainly renormalizable as well as unitary, so it gives us a physically interesting toy model of perturbative quantum gravity in three dimensions.Comment: 13 pages, no figure

    Mosquito Surveillance Program Using Ovitraps Detected Aedes aegypti at the Honolulu International Airport in 2012

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    mosquito surveillance program using ovitraps at the Honolulu In- ternational Airport (HIA), Hawaii, USA May 2010 to June 2012 revealed that A. albopictus egg counts fluctuated over time during the surveillance program and the highest oviposition was observed from February to May 2011 and the lowest was from September to November 2011. Positive correlations found between a given week’s rainfall and egg counts 1 and 2 weeks later suggested that rainfall triggered the hatching of eggs which were laid before the rainfall, rather than di- rectly stimulating adult oviposition. In January and June 2012, Aedes aegypti was discovered from a small vegetated area located between terminals for out-of-state and within-state flights. This species had not been confirmed present on Oahu at least since 1948. This finding has led us to intensify our surveillance program at the airport, with the hope that we would improve our understanding of the nature of mosquito introductions at this important port of entry for the Hawaiian Islands

    Analysis of IgE turnover in non-sensitized and sensitized rats.

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    BACKGROUND: Although the levels of immunoglobulin E (IgE) in the circulating blood are often elevated in patients with allergic diseases, such levels cannot always be considered as pathognomonic signs of allergy. The induction of allergic reactions in the tissue was inferred to be related to the amount of IgE passing through the vascular wall. AIMS: We attempted to clarify which compartment, the intravascular or extravascular, plays an important role in the regulation of the turnover of rat IgE. METHODS: The level of DNP-specific rat IgE in the serum was estimated by IgE-capture enzyme-linked immunosorbent assay, and the turnover of IgE was analyzed from its pharmacokinetic parameters. RESULTS: The transfer rate constants from the central to tissue compartment (Kct) were larger than those from the tissue to central compartment (Ktc) irrespective of the sensitized state. The value of the distribution volume of the tissue compartment (Vt) was larger than that of the distribution volume of the central compartment (Vc) irrespective of the sensitized state. CONCLUSIONS: These Findings suggest that the short half-life of rat IgE in the circulation could be attributable to the distribution of IgE from the intravascular to the extravascular compartment

    Bending AdS Waves with New Massive Gravity

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    We study AdS-waves in the three-dimensional new theory of massive gravity recently proposed by Bergshoeff, Hohm, and Townsend. The general configuration of this type is derived and shown to exhibit different branches, with different asymptotic behaviors. In particular, for the special fine tuning m2=±1/(2l2)m^2=\pm1/(2l^2), solutions with logarithmic fall-off arise, while in the range m2>1/(2l2)m^2>-1/(2l^2), spacetimes with Schrodinger isometry group are admitted as solutions. Solutions that are asymptotically AdS3_3, both for Brown-Henneaux and for the weakened boundary conditions, are also identified. The metric function that characterizes the profile of the AdS-wave behaves as a massive excitation on the spacetime, with an effective mass given by meff2=m21/(2l2)m_{eff}^2=m^2-1/(2l^2). For the critical value m2=1/(2l2)m^2=-1/(2l^2), the value of the effective mass precisely saturates the Breitenlohner-Freedman bound for the AdS3_3 space where the wave is propagating on. The analogies with the AdS-wave solutions of topologically massive gravity are also discussed. Besides, we consider the coupling of both massive deformations to Einstein gravity and find the exact configurations for the complete theory, discussing all the different branches exhaustively. One of the effects of introducing the Chern-Simons gravitational term is that of breaking the degeneracy in the effective mass of the generic modes of pure New Massive Gravity, producing a fine structure due to parity violation. Another effect is that the zoo of exact logarithmic specimens becomes considerably enlarged.Comment: 9 pages. Minor typos correcte

    Организационные резервы повышения производительности труда на предприятиях нефтегазовой отрасли

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    Проблема повышения производительности труда в современной экономике России имеет значительную актуальность, поскольку повышение уровня производительности труда является важнейшим условием социально-экономического развития общества, устойчивого экономического роста и повышения конкурентоспособности национальной экономики. Актуальность представленного исследования определяется необходимостью повышения производительности труда на современных предприятиях России, что может быть достигнуто за счет реализации организационных резервов роста. Целью исследования является структурирование факторов, оказывающих влияние на уровень производительности труда, подтверждение значимости организационных резервов роста, апробация методики выявления организационных резервов повышения производительности труда. Методы исследования. В настоящей работе нашли применение методы сбора первичной экономической информации, включая анализ законодательных и нормативно-правовых актов РФ, официальных статистических данных, данных публичной отчетности отечественных предприятий, анализ прочих открытых источников информации, системный подход, методы статистического и сравнительного анализа. The country's labor productivity in modern Russia over recent years has acquired impressive relevance. Since it is a key indicator of overall economic efficiency, strong labor productivity growth has always been a sufficient condition for socio-economic development, economic stability and enhancing competitiveness of the national economy. The relevance of the study is determined by the urgency of the labor productivity growth at the modern Russian factories that can be achieved through realization of organizational reserves. The main aim of the study is identifying and structuring the factors that seem to affect labor productivity level. It is also pointed at corroborating the necessity of labor productivity growth and approbation of organizational reserves seeking method. Methods. In the present work different methods of information gathering and processing were used to obtain the economic data including the analysis of appropriate laws and regulations, official statistics, companies' public statements and reporting and other open available resources. Also system approach, comparative and statistical analysis were adopted in this research

    Extra gauge symmetries in BHT gravity

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    We study the canonical structure of the Bergshoeff-Hohm-Townsend massive gravity, linearized around a maximally symmetric background. At the critical point in the space of parameters, defined by Λ0/m2=1\Lambda_0/m^2=-1, we discover an extra gauge symmetry, which reflects the existence of the partially massless mode. The number of the Lagrangian degrees of freedom is found to be 1. We show that the canonical structure of the theory at the critical point is unstable under linearization.Comment: LATEX, 12 page

    Discussing Quantum Aspects of Higher-Derivative 3D-Gravity in the First-Order Formalism

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    In this paper, we reassess the issue of deriving the propagators and identifying the spectrum of excitations associated to the vielbein and spin connection of (1+2)-D gravity in the presence of dynamical torsion, while working in the first-order formulation. A number of peculiarities is pointed out whenever the Chern-Simons term is taken into account along with a combination of bilinear terms in the torsion tensor. We present a procedure to derive the full set of propagators, based on an algebra of enlarged spin-type operators, and we discuss under which conditions the poles of the tree-level 2-point functions correspond to physical excitations that do not conflict with causality and unitarity

    Three-dimensional black holes, gravitational solitons, kinks and wormholes for BHT massive gravity

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    The theory of massive gravity in three dimensions recently proposed by Bergshoeff, Hohm and Townsend (BHT) is considered. At the special case when the theory admits a unique maximally symmetric solution, a conformally flat space that contains black holes and gravitational solitons for any value of the cosmological constant is found. For negative cosmological constant, the black hole is characterized in terms of the mass and the "gravitational hair" parameter, providing a lower bound for the mass. For negative mass parameter, the black hole acquires an inner horizon, and the entropy vanishes at the extremal case. Gravitational solitons and kinks, being regular everywhere, are obtained from a double Wick rotation of the black hole. A wormhole solution in vacuum that interpolates between two static universes of negative spatial curvature is obtained as a limiting case of the gravitational soliton with a suitable identification. The black hole and the gravitational soliton fit within a set of relaxed asymptotically AdS conditions as compared with the ones of Brown and Henneaux. In the case of positive cosmological constant the black hole possesses an event and a cosmological horizon, whose mass is bounded from above. Remarkably, the temperatures of the event and the cosmological horizons coincide, and at the extremal case one obtains the analogue of the Nariai solution, dS2×S1dS_{2}\times S^{1}. A gravitational soliton is also obtained through a double Wick rotation of the black hole. The Euclidean continuation of these solutions describes instantons with vanishing Euclidean action. For vanishing cosmological constant the black hole and the gravitational soliton are asymptotically locally flat spacetimes. The rotating solutions can be obtained by boosting the previous ones in the tϕt-\phi plane.Comment: Talk given at the "Workshop on Gravity in Three Dimensions," 14-24 April 2009, ESI, Vienna. 30 pages, 6 figures. V2: minor changes and section 6 slightly improved. Last version for JHE

    Hamiltonian analysis of BHT massive gravity

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    We study the Hamiltonian structure of the Bergshoeff-Hohm-Townsend (BHT) massive gravity with a cosmological constant. In the space of coupling constants (Λ0,m2)(\Lambda_0,m^2), our canonical analysis reveals the special role of the condition Λ0/m21\Lambda_0/m^2\neq-1. In this sector, the dimension of the physical phase space is found to be N=4N^*=4, which corresponds to two Lagrangian degree of freedom. When applied to the AdS asymptotic region, the canonical approach yields the conserved charges of the BTZ black hole, and central charges of the asymptotic symmetry algebra.Comment: LATEX, 21 pages; v2: minor correction
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