61 research outputs found

    New hairy black hole solutions with a dilaton potential

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    We consider black hole solutions with a dilaton field possessing a nontrivial potential approaching a constant negative value at infinity. The asymptotic behaviour of the dilaton field is assumed to be slower than that of a localized distribution of matter. A nonabelian SU(2) gauge field is also included in the total action. The mass of the solutions admitting a power series expansion in 1/r1/r at infinity and preserving the asymptotic anti-de Sitter geometry is computed by using a counterterm subtraction method. Numerical arguments are presented for the existence of hairy black hole solutions for a dilaton potential of the form V(ϕ)=C1exp(2α1ϕ)+C2exp(2α2ϕ)+C3V(\phi)=C_1 \exp(2\alpha_1 \phi)+C_2 \exp(2\alpha_2 \phi)+C_3, special attention being paid to the case of N=4,D=4{\cal N}=4, D=4 gauged supergravity model of Gates and Zwiebach.Comment: 12 pages, 4 figures; v2:references added, typos corrected, small changes in Section

    Shaping black holes with free fields

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    Starting from a metric Ansatz permitting a weak version of Birkhoff's theorem we find static black hole solutions including matter in the form of free scalar and p-form fields, with and without a cosmological constant \Lambda. Single p-form matter fields permit multiple possibilities, including dyonic solutions, self-dual instantons and metrics with Einstein-Kaelher horizons. The inclusion of multiple p-forms on the other hand, arranged in a homogeneous fashion with respect to the horizon geometry, permits the construction of higher dimensional dyonic p-form black holes and four dimensional axionic black holes with flat horizons, when \Lambda<0. It is found that axionic fields regularize black hole solutions in the sense, for example, of permitting regular -- rather than singular -- small mass Reissner-Nordstrom type black holes. Their cosmic string and Vaidya versions are also obtained.Comment: 38 pages. v2: minor changes, published versio

    Boundary stress-energy tensor and Newton-Cartan geometry in Lifshitz holography

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    For a specific action supporting z = 2 Lifshitz geometries we identify the Lifshitz UV completion by solving for the most general solution near the Lifshitz boundary. We identify all the sources as leading components of bulk fields which requires a vielbein formalism. This includes two linear combinations of the bulk gauge field and timelike vielbein where one asymptotes to the boundary timelike vielbein and the other to the boundary gauge field. The geometry induced from the bulk onto the boundary is a novel extension of Newton-Cartan geometry that we call torsional Newton-Cartan (TNC) geometry. There is a constraint on the sources but its pairing with a Ward identity allows one to reduce the variation of the on-shell action to unconstrained sources. We compute all the vevs along with their Ward identities and derive conditions for the boundary theory to admit conserved currents obtained by contracting the boundary stress-energy tensor with a TNC analogue of a conformal Killing vector. We also obtain the anisotropic Weyl anomaly that takes the form of a Hořava-Lifshitz action defined on a TNC geometry. The Fefferman-Graham expansion contains a free function that does not appear in the variation of the on-shell action. We show that this is related to an irrelevant deformation that selects between two different UV completions

    Introduction: A new role for emotions in Epistemology?

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    Expressivismus in Gebrauchstheorien der Bedeutung

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    John Stuart Mill zur Einführung

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    John Stuart Mill prägt die gesellschaftlichen und moralischen Ideale der modernen Welt wie kaum ein anderer. Schriften wie On Liberty, Utilitarianism und System of Logic gehören zu den meist diskutierten Klassikern der philosophischen Tradition. Seine Subjection of Women ist ein Grundlagenwerk des modernen Feminismus, und in den Considerations on Representative Government und anderen Arbeiten entwickelt er eine Theorie deliberativer Demokratie. Diese Einführung gibt einen Überblick über die wesentlichen Einsichten und Anliegen John Stuart Mills und erläutert die zentralen Forschungskontroversen. Besonderen Wert legt sie auf die Darstellung der Verknüpfungspunkte zwischen den zumeist getrennt behandelten Ideen Mills in der Politischen Ökonomie und der Theoretischen und Praktischen Philosophie. Dabei zeigt sich Mill als erstaunlich aktueller und radikaler Denker

    p300-mediated acetylation of the Rothmund-Thomson-syndrome gene product RECQL4 regulates its subcellular localization

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    RECQL4 belongs to the conserved RecQ family of DNA helicases, members of which play important roles in the maintenance of genome stability in all organisms that have been examined. Although genetic alterations in the RECQL4 gene are reported to be associated with three autosomal recessive disorders (Rothmund-Thomson, RAPADILINO and Baller-Gerold syndromes), the molecular role of RECQL4 still remains poorly understood. Here, we show that RECQL4 specifically interacts with the histone acetyltransferase p300 (also known as p300 HAT), both in vivo and in vitro, and that p300 acetylates one or more of the lysine residues at positions 376, 380, 382, 385 and 386 of RECQL4. Furthermore, we report that these five lysine residues lie within a short motif of 30 amino acids that is essential for the nuclear localization of RECQL4. Remarkably, the acetylation of RECQL4 by p300 in vivo leads to a significant shift of a proportion of RECQL4 protein from the nucleus to the cytoplasm. This accumulation of the acetylated RECQL4 is a result of its inability to be imported into the nucleus. Our results provide the first evidence of a post-translational modification of the RECQL4 protein, and suggest that acetylation of RECQL4 by p300 regulates the trafficking of RECQL4 between the nucleus and the cytoplasm

    Aircraft-based CH<sub>4</sub> flux estimates for validation of emissions from an agriculturally dominated area in Switzerland

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    For regional-scale investigations of greenhouse gas budgets the spatially explicit information from local emission sources is needed, which then can be compared with flux measurements. Here we present the first validation of a section of a spatially explicit CH4 emission inventory of Switzerland. The validation was done for the agriculturally dominated Reuss Valley using measurements from a low-flying aircraft (50–500 m above ground level). We distributed national emission estimates to a grid with 500 m cell size using available geostatistical data. Validation flux measurements were obtained using the eddy covariance (EC) technique and the boundary layer budgeting (BLB) approach that only uses the mean concentrations of the same aircraft transects. Inventory estimates for the flux footprint of the aircraft measurements were lowest (median 0.40 μg CH4 m−2 s−1), and BLB fluxes were highest (1.02 μg CH4 m−2 s−1) for the Reuss Valley, with EC fluxes in between (0.62 μg CH4 m−2 s−1). Flux estimates frommeasurements and inventory are within the same order of magnitude, but measured fluxes were significantly larger than the inventory emission estimates. The differences are larger than the uncertainties associated with storage of manure, temperature dependence of emissions, diurnal cycle of enteric fermentation by cattle, and the limitations of the inventory that only covers ≥90% of all expected methane emissions. From this we deduce that it is not unlikely that the Swiss CH4 emission inventory estimates are too low
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