2,342 research outputs found
Holographic chiral induced W-gravities
We study boundary conditions for 3-dimensional higher spin gravity that admit
asymptotic symmetry algebras expected of 2-dimensional induced higher spin
theories in the light cone gauge. For the higher spin theory based on sl(3, R)
plus sl(3,R) algebra, our boundary conditions give rise to one copy of
classical W3 and a copy of sl(3,R) or su(1,2) Kac-Moody symmetry algebra. We
propose that the higher spin theories with these boundary conditions describe
appropriate chiral induced W-gravity theories on the boundary. We also consider
boundary conditions of spin-3 higher spin gravity that admit u(1) plus u(1)
current algebra.Comment: 19 page
On Asymptotic Symmetries of 3d Extended Supergravities
We study asymptotic symmetry algebras for classes of three dimensional
supergravities with and without cosmological constant. In the first part we
generalise some of the non-Dirichlet boundary conditions of gravity to
extended supergravity theories, and compute their asymptotic symmetries. In
particular, we show that the boundary conditions proposed to holographically
describe the chiral induced gravity and Liouville gravity do admit extension to
the supergravity contexts with appropriate superalgebras as their asymptotic
symmetry algebras. In the second part we consider generalisation of the 3d
computation to extended supergravities without cosmological constant, and
show that their asymptotic symmetry algebras provide examples of nonlinear
extended superalgebras containing the algebra
An sl(2, R) current algebra from AdS_3 gravity
We provide a set of chiral boundary conditions for three-dimensional gravity
that allow for asymptotic symmetries identical to those of two-dimensional
induced gravity in light-cone gauge considered by Polyakov. These are the most
general boundary conditions consistent with the boundary terms introduced by
Compere, Song and Strominger recently. We show that the asymptotic symmetry
algebra of our boundary conditions is an sl(2,R) current algebra with level
given by c/6. The fully non-linear solution in Fefferman--Graham coordinates is
also provided along with its charges.Comment: 8 page
Modelling of acoustic transmission through perforated layer
The paper deals with modeling the acoustic transmission through a perforated interface plane separating two halfspaces occupied by the acoustic medium. We considered the two-scale homogenization limit of the standard acoustic problem imposed in the layer with the perforated periodic structure embedded inside. The homogenized transmission conditions govern the interface discontinuity of the acoustic pressure associated with the two halfspaces and the magnitude of the fictitious transversal acoustic velocity. By numerical examples we illustrate this novel approach of modeling the acoustic impedance of perforated interfaces
Machines vs Malaria: A Flow-Based Preparation of the Drug Candidate OZ439.
An efficient preparation of the antimalarial drug candidate OZ439, which was obtained by integrating a machine-assisted approach with batch processes, is reported. This approach allows a rapid and cost-effective production of the key intermediates that were readily elaborated into the target molecule.We are grateful to Croucher Foundation and Cambridge Trust (SHL), MEC-Spain (FPU-predoctoral grants, AG), Pfizer World-wide Research and Development (CB), the Xunta de Galicia Gov-ernment (JAS), and the EPSRC (SVL, grant n° EP/K0099494/1 and EP/K039520/1) for financial support.This is the final version. It first appeared at http://pubs.acs.org/doi/abs/10.1021/acs.orglett.5b01307
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