1,314 research outputs found
Non-Abelian (Hyperscaling Violating) Lifshitz Black Holes in General Dimensions
We consider Einstein gravities coupled to a cosmological constant and
multiple Yang-Mills fields in general dimensions and find that the
theories admit colored Lifshitz solutions with dynamic exponents . We also
introduce a Maxwell field and construct exact electric charged black holes that
asymptote to the 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 .Comment: Latex, 12 pages, a published version in PL
Godel Metrics with Chronology Protection in Horndeski Gravities
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
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 AdS 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
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
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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