4,542 research outputs found

    Perturbative Analysis of Universality and Individuality in Gravitational Waves from Neutron Stars

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    The universality observed in gravitational wave spectra of non-rotating neutron stars is analyzed here. We show that the universality in the axial oscillation mode can be reproduced with a simple stellar model, namely the centrifugal barrier approximation (CBA), which captures the essence of the Tolman VII model of compact stars. Through the establishment of scaled co-ordinate logarithmic perturbation theory (SCLPT), we are able to explain and quantitatively predict such universal behavior. In addition, quasi-normal modes of individual neutron stars characterized by different equations of state can be obtained from those of CBA with SCLPT.Comment: 29 pages, 10 figures, submitted to Astrophysical Journa

    Determination of the internal structure of neutron stars from gravitational wave spectra

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    In this paper the internal structure of a neutron star is shown to be inferrable from its gravitational-wave spectrum. Iteratively applying the inverse scheme of the scaled coordinate logarithmic perturbation method for neutron stars proposed by Tsui and Leung [Astrophys. J. {\bf 631}, 495 (2005)], we are able to determine the mass, the radius and the mass distribution of a star from its quasi-normal mode frequencies of stellar pulsation. In addition, accurate equation of state of nuclear matter can be obtained from such inversion scheme. Explicit formulas for the case of axial ww-mode oscillation are derived here and numerical results for neutron stars characterized by different equations of state are shown.Comment: 26 pages, 14 figures, submitted to Physical Review

    Bone regeneration with resorbable polylactide membrane and sponge in an unstable fracture model in rabbit radius

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    Open Access journalConference Theme: Bone Tissue EngineeringBACKGROUND: Healing of segmental diaphyseal bone defects in animals can be enhanced by covering the defects with resorbable polylactide membranes. Based on the results of bone healing in defects 10 mm long in the rabbit radii, it was suggested that the membranes prevents muscle and soft tissue from invading the defect and maintains osteogenic cells and osteogenic substances within the space covered with membrane, thus promoting new bone formation. OBJECTIVES: 1. To investigate and …published_or_final_versionpublished_or_final_versio

    Mapping of DNA markers linked to the cystic fibrosis locus on the long arm of chromosome 7

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    We have used a panel of eight human/mouse somatic-cell hybrids, each containing various portions of human chromosome 7, and three patient cell lines with interstitial deletions on chromosome 7 for localization of six DNA markers linked to the cystic fibrosis locus. Our data suggest that D7S15 is located in the region 7cen→q22, that MET is located in 7q22→31, and that D7S8 and 7C22 are located in q22→q32. The hybridization results for COL1A2 and TCRB are consistent with their previous assignment to 7q21→q22 and 7q32, respectively. Given the location of these six markers and their linkage relationships, it is probable that the cystic fibrosis locus is in either the distal region of band q22 or the proximal region of q31. Using the same set of cell lines, we have also examined the location of another chromosome 7 marker PGY1. The data show that PGY1 is located in the region 7cen→q22, a position very different from its previous assignment.published_or_final_versio

    Impact of disorder on the 5/2 fractional quantum Hall state

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    We compare the energy gap of the \nu=5/2 fractional quantum Hall effect state obtained in conventional high mobility modulation doped quantum well samples with those obtained in high quality GaAs transistors (heterojunction insulated gate field-effect transistors). We are able to identify the different roles that long range and short range disorders play in the 5/2 state and observe that the long range potential fluctuations are more detrimental to the strength of the 5/2 state than short-range potential disorder.Comment: PRL 106, 206806 (2011
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