59,865 research outputs found

    Multi-site observations of Delta Scuti stars 7 Aql and 8 Aql (a new Delta Scuti variable): The twelfth STEPHI campaign in 2003

    Full text link
    We present an analysis of the pulsation behaviour of the Delta Scuti stars 7 Aql (HD 174532) and 8 Aql (HD 174589) -- a new variable star -- observed in the framework of STEPHI XII campaign during 2003 June--July. 183 hours of high precision photometry were acquired by using four-channel photometers at three sites on three continents during 21 days. The light curves and amplitude spectra were obtained following a classical scheme of multi-channel photometry. Observations in different filters were also obtained and analyzed. Six and three frequencies have been unambiguously detected above a 99% confidence level in the range 0.090 mHz--0.300 mHz and 0.100 mHz-- 0.145 mHz in 7 Aql and 8 Aql respectively. A comparison of observed and theoretical frequencies shows that 7 Aql and 8 Aql may oscillate with p modes of low radial orders, typical among Delta Scuti stars. In terms of radial oscillations the range of 8 Aql goes from n=1 to n=3 while for 7 Aql the range spans from n=4 to n=7. Non-radial oscillations have to be present in both stars as well. The expected range of excited modes according to a non adiabatic analysis goes from n=1 to n=6 in both stars.Comment: 8 pages, 7 fugures, 5 tables, accepted for publication in Astronomical Journa

    Glial and axonal body fluid biomarkers are related to infarct volume, severity, and outcome.

    Get PDF
    Body fluid biomarkers of central nervous system damage may help improve the prognostic and diagnostic accuracy in ischemic stroke. We studied 53 patients. Stroke severity and outcome was rated using the National Institutes of Health Stroke Scale and modified Rankin scale. Ferritin, S100B, and NfH were measured in cerebrospinal fluid (CSF) and serum. Infarct volume was calculated from T2W images. CSF S100B (median 1.00 ng/mL) and CSF ferritin (10.0 ng/mL) levels were elevated in patients with stroke compared with control subjects (0.62 ng/mL, P < .0001; 2.34 ng/mL, P < .0001). Serum S100B (0.09 ng/mL) was higher in patients with stroke compared with control subjects (0.01 ng/mL). CSF S100B levels were higher in patients with a cardioembolic stroke (2.88 ng/mL) than in those with small-vessel disease (0.89 ng/mL, P < .05). CSF S100B levels correlated with the National Institutes of Health Stroke Scale score on admission (R = 0.56, P < .01) and the stroke volume (R = 0.44, P = .01). CSF S100B and NfH-SMI35 levels correlated with outcome on the modified Rankin scale. CSF S100B levels were related to stroke severity and infarct volume and highest in cardioembolic stroke

    Approximate solution of the pairing Hamiltonian in the Berggren basis

    Full text link
    We derive the approximate solution for the pairing Hamiltonian in the Berggren ensemble of single particle states including bound, resonance and non-resonant scattering states. We show that this solution is reliable in the limit of a weak pairing interaction

    Isospin mixing and the continuum coupling in weakly bound nuclei

    Full text link
    The isospin breaking effects due to the Coulomb interaction in weakly-bound nuclei are studied using the Gamow Shell Model, a complex-energy configuration interaction approach which simultaneously takes into account many-body correlations between valence nucleons and continuum effects. We investigate the near-threshold behavior of one-nucleon spectroscopic factors and the structure of wave functions along an isomultiplet. Illustrative calculations are carried out for the T=1 isobaric triplet. By using a shell-model Hamiltonian consisting of an isoscalar nuclear interaction and the Coulomb term, we demonstrate that for weakly bound or unbound systems the structure of isobaric analog states varies within the isotriplet and impacts the energy dependence of spectroscopic factors. We discuss the partial dynamical isospin symmetry present in isospin-stretched systems, in spite of the Coulomb interaction that gives rise to large mirror symmetry breaking effects.Comment: 10 pages, 5 figures ; published versio

    Uniform WKB approximation of Coulomb wave functions for arbitrary partial wave

    Full text link
    Coulomb wave functions are difficult to compute numerically for extremely low energies, even with direct numerical integration. Hence, it is more convenient to use asymptotic formulas in this region. It is the object of this paper to derive analytical asymptotic formulas valid for arbitrary energies and partial waves. Moreover, it is possible to extend these formulas for complex values of parameters.Comment: 5 pages, 2 figure

    Structure of Exotic Nuclei

    Full text link
    The progress in the modeling of exotic nuclei with an extreme neutron-to-proton ratio is discussed. Two topics are emphasized: (i) the quest for the universal microscopic nuclear energy density functional and (ii) the progress in the continuum shell model.Comment: 10 pages, 2 figures, presented by W. Nazarewicz at the International Symposium on "A New Era of Nuclear Structure Physics", Kurokawa Village (Niigata Pref.), Japan, Nov. 19-22, 200

    Weakly bound systems, continuum effects, and reactions

    Full text link
    Structure of weakly bound/unbound nuclei close to particle drip lines is different from that around the valley of beta stability. A comprehensive description of these systems goes beyond standard Shell Model and demands an open quantum system description of the nuclear many-body system. We approach this problem using the Gamow Shell Model which provides a fully microscopic description of bound and unbound nuclear states, nuclear decays, and reactions. We present in this paper the first application of the GSM for a description of the elastic and inelastic scattering of protons on 6He.Comment: Proc. Int. Conf. "Horizons of Innovative Theories, Experiments and Supercomputing in Nuclear Physics", June 4-7, 2012, New Orleans, Luisiana, USA; 10 pages, 4 figure
    corecore