2,857 research outputs found
Killing spinor space-times and constant-eigenvalue Killing tensors
A class of Petrov type D Killing spinor space-times is presented, having the
peculiar property that their conformal representants can only admit Killing
tensors with constant eigenvalues.Comment: 11 pages, submitted to CQ
Petrov type D pure radiation fields of Kundt's class
We present all Petrov type D pure radiation space-times, with or without
cosmological constant, with a shear-free, non-diverging geodesic principal null
congruence
Little willies as community-building heritage: A bottom-up approach to the European Capital of Culture initiative
Rotating solenoidal perfect fluids of Petrov type D
We prove that aligned Petrov type D perfect fluids for which the vorticity
vector is not orthogonal to the plane of repeated principal null directions and
for which the magnetic part of the Weyl tensor with respect to the fluid
velocity has vanishing divergence, are necessarily purely electric or locally
rotationally symmetric. The LRS metrics are presented explicitly.Comment: 6 pages, no figure
Teacher feedback during active learning : the development and evaluation of a professional development program
Algebraically general, gravito-electric rotating dust
The class of gravito-electric, algebraically general, rotating `silent' dust
space-times is studied. The main invariant properties are deduced. The number
of functionally independent zero-order Riemann invariants satisfies
and special attention is given to the subclass .
Whereas there are no -term limits comprised in the class, the limit
for vanishing vorticity leads to two previously derived irrotational dust
families with , and the shear-free limit is the G\"{o}del universe.Comment: 10 pages, changed to revtex style, extended discussion section, minor
correction
Purely radiative irrotational dust spacetimes
We consider irrotational dust spacetimes in the full non-linear regime which
are "purely radiative" in the sense that the gravitational field satisfies the
covariant transverse conditions div(H) = div(E) = 0. Within this family we show
that the Bianchi class A spatially homogeneous dust models are uniquely
characterised by the condition that is diagonal in the shear-eigenframe.Comment: 6 pages, ERE 2006 conference, minor correction
Maternal anxiety during pregnancy and reactivity, self-regulation and internalizing problems in childhood and adolescence
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