21,049 research outputs found

    Stationary Bianchi type II perfect fluid models

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    Einstein's field equations for stationary Bianchi type II models with a perfect fluid source are investigated. The field equations are rewritten as a system of autonomous first order differential equations. Dimensionless variables are subsequently introduced for which the reduced phase space is compact. The system is then studied qualitatively using the theory of dynamical systems. It is shown that the locally rotationally symmetric models are not asymptotically self-similar for small values of the independent , tovariable. A new exact solution is also given.Comment: 6 pages, 1 figure LaTeX. To appear in JM

    The micrometeoroid experiment on the OGO 2 satellite

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    Micrometeoroids in earths dust cloud obtained from OGO-B satellit

    Uni-directional polymerization leading to homochirality in the RNA world

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    The differences between uni-directional and bi-directional polymerization are considered. The uni-directional case is discussed in the framework of the RNA world. Similar to earlier models of this type, where polymerization was assumed to proceed in a bi-directional fashion (presumed to be relevant to peptide nucleic acids), left-handed and right-handed monomers are produced via an autocatalysis from an achiral substrate. The details of the bifurcation from a racemic solution to a homochiral state of either handedness is shown to be remarkably independent of whether the polymerization in uni-directional or bi-directional. Slightly larger differences are seen when dissociation is allowed and the dissociation fragments are being recycled into the achiral substrate.Comment: 9 pages, 4 figures, submitted to Astrobiolog

    Heat capacity mapping mission project HCM-051

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    There are no author-identified significant results in this report

    The Low-level Spectrum of the W3W_3 String

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    We investigate the spectrum of physical states in the W3W_3 string theory, up to level 2 for a multi-scalar string, and up to level 4 for the two-scalar string. The (open) W3W_3 string has a photon as its only massless state. By using screening charges to study the null physical states in the two-scalar W3W_3 string, we are able to learn about the gauge symmetries of the states in the multi-scalar W3W_3 string.Comment: 31 pages, Plain Tex, CTP TAMU-70/92, Goteborg ITP 92-43, Imperial/TP/91-92/22, KCL-TH-92-

    Description of superdeformed bands in light N=Z nuclei using the cranked HFB method

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    Superdeformed states in light N=ZN=Z nuclei are studied by means of the self-consistent cranking calculation (i.e., the P + QQ model based on the cranked Hartree-Fock-Bogoliubov method). Analyses are given for two typical cases of superdeformed bands in the A40A \simeq 40 mass region, that is, bands where backbending is absent (40^{40}Ca) and present (36^{36}Ar). Investigations are carried out, particularly for the following points: cross-shell excitations in the sd and pf shells; the role of the g9/2_{9/2} and d5/2_{5/2} orbitals; the effect of the nuclear pairing; and the interplay between triaxiality and band termination.Comment: 17 pages, 18 figures, accepted in Phys. Rev.

    The effects of deformation and pairing correlations on nuclear charge form factor

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    A set of moderately deformed sds-d shell nuclei is employed for testing the reliability of the nuclear ground state wave functions which are obtained in the context of a BCS approach and offer a simultaneous consideration of deformation and pairing correlations effects. In this method, the mean field is assumed to be an axially symmetric Woods-Saxon potential and the effective two-body interaction is a monopole pairing force. As quantities of main interest we have chosen the nuclear form factors, the occupancies of the active (surface) orbits and the Fermi sea depletion, which provide quite good tests for microscopic descriptions of nuclei within many body theories. For our comparisons with results emerging from other similar methods, an axially deformed harmonic oscillator field is also utilized.Comment: 20 pages, 12 figures, 2 table

    Heat Capacity Mapping Mission

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    The Tasman Front was delineated by airborne expendable bathythermograph survey; and an Heat Capacity Mapping Mission (HCMM) IR image on the same day shows the same principal features as determined from ground-truth. It is clear that digital enhancement of HCMM images is necessary to map ocean surface temperatures and when done, the Tasman Front and other oceanographic features can be mapped by this method, even through considerable scattered cloud cover
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