52,728 research outputs found

    Exact Quantum States for all Two-Dimensional Dilaton Gravity Theories

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    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

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    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

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    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

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    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

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    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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