1,314 research outputs found

    Non-Abelian (Hyperscaling Violating) Lifshitz Black Holes in General Dimensions

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    We consider Einstein gravities coupled to a cosmological constant and multiple SU(2)SU(2) Yang-Mills fields in general dimensions and find that the theories admit colored Lifshitz solutions with dynamic exponents z>1z>1. We also introduce a Maxwell field and construct exact electric charged black holes that asymptote to the z=D1z=D-1 colored Lifshitz spacetimes and analyse their thermodynamical first law. Furthermore, we introduce a dilaton to the system and construct Lifshitz spacetimes with hyperscaling violations. After turning on the Maxwell field, we obtain a class of hyperscaling violating Lifshitz black holes when θ=2D2[z(D1)]\theta=\frac{2}{D-2}[z-(D-1)].Comment: Latex, 12 pages, a published version in PL

    Godel Metrics with Chronology Protection in Horndeski Gravities

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    G\"odel universe, one of the most interesting exact solutions predicted by General Relativity, describes a homogeneous rotating universe containing naked closed time-like curves (CTCs). It was shown that such CTCs are the consequence of the null energy condition in General Relativity. In this paper, we show that the G\"odel-type metrics with chronology protection can emerge in Einstein-Horndeski gravity. We construct such exact solutions also in Einstein-Horndeski-Maxwell and Einstein-Horndeski-Proca theories.Comment: Latex, 11 pages, references adde

    BPS Kerr-AdS Time Machines

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    It was recently observed that Kerr-AdS metrics with negative mass describe smooth spacetimes that have a region with naked closed time-like curves, bounded by a velocity of light surface. Such spacetimes are sometimes known as time machines. In this paper we study the BPS limit of these metrics, and find that the mass and angular momenta become discretised. The completeness of the spacetime also requires that the time coordinate be periodic, with precisely the same period as that which arises for the global AdS in which the time machine spacetime is immersed. For the case of equal angular momenta in odd dimensions, we construct the Killing spinors explicitly, and show they are consistent with the global structure. Thus in examples where the solution can be embedded in a gauged supergravity theory, they will be supersymmetric. We also compare the global structure of the BPS AdS3_3 time machine with the BTZ black hole, and show that the global structure allows to have two different supersymmetric limits.Comment: latex, 29 pages, minor typos corrected and references adde

    4-Methyl­benzaldehyde thio­semi­carbazone

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    The title compound, C9H11N3S, was prepared by reacting 4-methyl­benzaldehyde with thio­semicarbazide. An intra­molecular N—H⋯N hydrogen bond helps to establish the observed mol­ecular conformation. The crystal packing is realized by inter­molecular N—H⋯S hydrogen bonds

    Cloning and functional analysis in transgenic tobacco of a tapetum-specific promoter from Arabidopsis

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    The 5’-flanking region of 1174 bp upstream of the translation start point (TSP) of a reported Arabidopsis anther-specific gene, Anther7 gene (ATA7), which putatively  encodes a protein related to lipid transfer protein, was cloned and functionally analyzed in transgenic tobacco after been fused with β- glucuronidase (GUS) gene reporter. Histochemical GUS staining of the transgenic plants showed that the cloned fragment did drive GUS expression exclusively in the anther, not  in any other parts of floral organs, including pollens and nor in any vegetative tissue. Transverse section of the GUS-blue anthers disclosed that the blue cells were present uniquely in the tapetum of the anther. A series of 5’-deletion of cloned fragment indicated that a short segment of 179 bp upstream of the TSP (-155 bp  upstream of the transcription start site) retained not only the promoter’s driving power, but also its tapetum-specificity. Cis-acting element search in this short segment revealed the presence of numbers of organ- and tissuespecific motifs, including pollen-specific LAT52 and SLG13. These results indicated that the  tapetumspecificity of ATA7 gene is mainly conferred by its promoter, and such a promoter, in particular, the core one should be useful both for identification of tapetum-involved genes and for biotechnological applications.Key words: Arabidopsis, Anther7 gene of Arabidopsis theliana (ATA7), anther-specific promoter, tapetumspecific promoter
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