52,728 research outputs found
Exact Quantum States for all Two-Dimensional Dilaton Gravity Theories
It is shown that the recently obtained quantum wave functionals in terms of
the CJZ variables for generic 2d dilaton gravity are equivalent to the
previously reported exact quantum wave functionals in geometrical variables. A
third representation of these exact quantum states is also presented
The use of tethers for payload orbital transfer. Continuation of investigation of electrodynamic stabilization and control of long orbiting tethers, volume 2
The SKYHOOK program was used to do simulations of two cases of the use of the tether for payload orbital transfer. The transport of a payload along the tether from a heavy lower platform to an upper launching platform is considered. A numerical example of the Shuttle launching a payload using an orbital tether facility is described
WIRIS OM tools: a semantic formula editor
With the increasing reliance on computers for the automatic processing
of information a new method is needed for editing mathematical formulae.
We are used to WYSIWYG editors that produce beautiful presentations of
formulae and store the typesetting primitives rather than the meaning of the
formulas. However, new services such as database searching or calculation
web-services work best if they have access to the semantic information behind
a formula. This can only be done with a new generation of formula editors.
In this paper we present WIRIS OM Tools [17], a semantic oriented formula
editor which addresses these concerns. It is based on the OpenMath language
and a suitable transformation process between OpenMath and MathML ex-
pressions. Additionally, this approach adds new features for the users such
as error, type and syntax checking. The editor is currently being used in the
LeActiveMath and WebALT projects
New measurements of magnetic fields of roAp stars with FORS1 at the VLT
Magnetic fields play a key role in the pulsations of rapidly oscillating Ap
(roAp) stars since they are a necessary ingredient of all pulsation excitation
mechanisms proposed so far. This implies that the proper understanding of the
seismological behaviour of the roAp stars requires knowledge of their magnetic
fields. However, the magnetic fields of the roAp stars are not well studied.
Here we present new results of measurements of the mean longitudinal field of
14 roAp stars obtained from low resolution spectropolarimetry with FORS1 at the
VLT.Comment: 5 pages, accepted for publication in A&
Minkowski-type and Alexandrov-type theorems for polyhedral herissons
Classical H.Minkowski theorems on existence and uniqueness of convex
polyhedra with prescribed directions and areas of faces as well as the
well-known generalization of H.Minkowski uniqueness theorem due to
A.D.Alexandrov are extended to a class of nonconvex polyhedra which are called
polyhedral herissons and may be described as polyhedra with injective spherical
image.Comment: 19 pages, 8 figures, LaTeX 2.0
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