819 research outputs found

    Proton and neutron correlations in 10^{10}B

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    We investigate positive-parity states of 10^{10}B with the calculation of antisymmetrized molecular dynamics focusing on pnpn pair correlations. We discuss effects of the spin-orbit interaction on energy spectra and pnpn correlations of the JπT=11+0J^\pi T=1^+_10, =31+0=3^+_10, and 01+10^+_11 states. The 11+01^+_10 state has almost no energy gain of the spin-orbit interaction, whereas the 31+03^+_10 state gains the spin-orbit interaction energy largely to come down to the ground state. We interpret a part of the two-body spin-orbit interaction in the adopted effective interactions as a contribution of the genuine NNNNNN force, and find it to be essential for the level ordering of the 31+03^+_10 and 11+01^+_10 states in 10^{10}B. We also apply a 2α+pn2\alpha+pn model to discuss effects of the spin-orbit interaction on T=0T=0 and T=1T=1 pnpn pairs around the 2α\alpha core. In the spin-aligned JπT=3+0J^\pi T=3^+0 state, the spin-orbit interaction affects the (ST)=(10)(ST)=(10) pair attractively and keeps the pair close to the core, whereas, in the 1+01^+0 state, it gives a minor effect to the (ST)=(10)(ST)=(10) pair. In the 0+10^+1 state, the (ST)=(01)(ST)=(01) pair is somewhat dissociated by the spin-orbit interaction.Comment: 12 pages 9 figure

    Breaking of N=8 magicity in 13Be

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    Structure of 13^{13}Be was investigated with antisymmetrized molecular dynamics. The variation after spin and parity projections was performed. An unnatural parity 1/21/2^- state was suggested to be lower than 5/2+5/2^+ state indicating that vanishing of the N=8 magic number occurs in 13^{13}Be. A low-lying 3/2+3/2^+ state with a 2ω2\hbar\omega configuration was also suggested. Developed cluster structures were found in the intruder states. Lowering mechanism of the intruder states was discussed in terms of molecular orbitals around a 2α2\alpha core.Comment: 9 pages, 8 figures, submitted to PR

    Construction of a topological charge on fuzzy S^2 x S^2 via Ginsparg-Wilson relation

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    We construct a topological charge of gauge field configurations on a fuzzy S^2xS^2 by using a Dirac operator satisfying the Ginsparg-Wilson relation. The topological charge defined on the fuzzy S^2xS^2 can be interpreted as a noncommutative (or matrix) generalization of the 2nd Chern character on S^2xS^2. We further calculate the number of chiral zero modes of the Dirac operator in topologically nontrivial gauge configurations. Generalizations of our formulation to fuzzy (S^2)^k are also discussed.Comment: 30 pages, typo corrected, version published in Phys.Rev.

    Anticardiolipin Antibodies Recognize β(2)-Glycoprotein I Structure Altered by Interacting with an Oxygen Modified Solid Phase Surface

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    Anticardiolipin antibodies (aCL) derived from the sera of individuals exhibiting the antiphospholipid syndrome (APS) directly bind to beta(2)-glycoprotein I (beta(2)-GPI), which is adsorbed to an oxidized polystyrene surface. Oxygen atoms were introduced on a polystyrene surface by irradiation with electron or gamma-ray radiation. X-ray photoelectron spectroscopy revealed the irradiated surfaces were oxidized to generate C-O and C=O moieties. aCL derived from either APS patients or (NZW x BXSB)F-1 mice bound to beta(2)-GPI coated on the irradiated plates, depending on the radiation dose. Antibody binding to beta(2)-GPI on the irradiated plates was competitively inhibited by simultaneous addition of cardiolipin (CL)-coated latex beads mixed together with beta(2)-GPI but were unaffected by addition of excess beta(2)-GPI, CL micelles, or CL-coated latex beads alone. There was a high correlation between binding values of aCL in sera from 40 APS patients obtained by the anti-beta(2)-GPI enzyme-linked immunosorbent assay (ELISA) using the irradiated plates and those by the beta(2)-GPI-dependent aCL ELISA. Therefore, aCL have specificity for an epitope on beta(2)-GPI. This epitope is expressed by a conformational change occurring when beta(2)-GPI interacts with an oxygen-substituted solid phase surface

    A new N* resonance as a hadronic molecular state

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    We report our recent work on a hadronic molecule state of the KbarKN system with I=1/2 and J^P=1/2^+. We assume that the Lambda(1405) resonance and the scalar mesons, f_{0}(980), a_{0}(980), are reproduced as quasi-bound states of KbarN and KbarK, respectively. Performing non-relativistic three-body calculations with a variational method for this system, we find a quasibound state of the KbarKN system around 1910 MeV below the three-body breakup threshold. This state corresponds to a new baryon resonance of N* with J^P=1/2^+. We find also that this resonance has the cluster structure of the two-body bound states keeping their properties as in the isolated two-particle systems. We also briefly discuss another hadronic molecular state composed by two Kbar and one N, which corresponds to a Xi^* resonance.Comment: Talk given at Workshop on the Physics of Excited Nucleon -- NSTAR2009, Beijing April 19 - 22, 200

    Triaxial quadrupole deformation dynamics in sd-shell nuclei around 26Mg

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    Large-amplitude dynamics of axial and triaxial quadrupole deformation in 24,26Mg, 24Ne, and 28Si is investigated on the basis of the quadrupole collective Hamiltonian constructed with use of the constrained Hartree-Fock-Bogoliubov plus the local quasiparticle random phase approximation method. The calculation reproduces well properties of the ground rotational bands, and beta and gamma vibrations in 24Mg and 28Si. The gamma-softness in the collective states of 26Mg and 24Ne are discussed. Contributions of the neutrons and protons to the transition properties are also analyzed in connection with the large-amplitude quadrupole dynamics.Comment: 16 pages, 18 figures, submitted to Phys. Rev.

    Index theorem in spontaneously symmetry-broken gauge theories on a fuzzy 2-sphere

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    We consider a gauge-Higgs system on a fuzzy 2-sphere and study the topological structure of gauge configurations, when the U(2) gauge symmetry is spontaneously broken to U(1) times U(1) by the vev of the Higgs field. The topology is classified by the index of the Dirac operator satisfying the Ginsparg-Wilson relation, which turns out to be a noncommutative analog of the topological charge introduced by 't Hooft. It can be rewritten as a form whose commutative limit becomes the winding number of the Higgs field. We also study conditions which assure the validity of the formulation, and give a generalization of the admissibility condition. Finally we explicitly calculate the topological charge of a one-parameter family of configurations.Comment: 37 pages, 3 figures, typo corrected, version published in Physical Review

    The Diffusion of the Magnetization Profile in the XX-model

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    By the CC^*-algebraic method, we investigate the magnetization profile in the intermediate time of diffusion. We observe a transition from monotone profile to non-monotone profile. This transition is purely thermal.Comment: Accepted for publication in Phys. Rev.

    Cilostazol Attenuates AngII-Induced Cardiac Fibrosis in apoE Deficient Mice

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    Cardiac fibrosis is characterized by the net accumulation of extracellular matrix in the myocardium and is an integral component of most pathological cardiac conditions. Cilostazol, a selective inhibitor of phosphodiesterase type III with anti-platelet, anti-mitogenic, and vasodilating properties, is widely used to treat the ischemic symptoms of peripheral vascular disease. Here, we investigated whether cilostazol has a protective effect against Angiotensin II (AngII)-induced cardiac fibrosis. Male apolipoprotein E-deficient mice were fed either a normal diet or a diet containing cilostazol (0.1% wt/wt). After 1 week of diet consumption, the mice were infused with saline or AngII (1000 ng kg(-1) min(-1)) for 28 days. AngII infusion increased heart/body weight ratio (p < 0.05), perivascular fibrosis (p < 0.05), and interstitial cardiac fibrosis (p < 0.0001), but were significantly attenuated by cilostazol treatment (p < 0.05, respectively). Cilostazol also reduced AngII-induced increases in fibrotic and inflammatory gene expression (p < 0.05, respectively). Furthermore, cilostazol attenuated both protein and mRNA abundance of osteopontin induced by AngII in vivo. In cultured human cardiac myocytes, cilostazol reduced mRNA expression of AngII-induced osteopontin in dose-dependent manner. This reduction was mimicked by forskolin treatment but was cancelled by co-treatment of H-89. Cilostazol attenuates AngII-induced cardiac fibrosis in mice through activation of the cAMP-PKA pathway

    Pupil size is modulated by the size of equal-luminance gratings

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    © 2020 The Authors. Pupil size changes with light. For this reason, researchers studying the effect of attention, contextual processing, and arousal on the pupillary response have matched the mean luminance of their stimuli across conditions to eliminate the contribution of differences in light levels. Here, we argue that the match of mean luminance is not enough. In Experiment 1, we presented a circular sinewave grating on a gray background for 2 seconds. The area of the grating could be 3°, 6°, or 9°. The mean luminance of each grating was equal to the luminance of the gray background, such that regardless of the size of the grating there was no change in mean luminance between conditions. Participants were asked to fixate the center of the grating and passively view it. We found that in all size conditions, there was a pupil constriction starting at about 300 ms after stimulus onset, and the pupil constriction increased with the size of the grating. In Experiment 2, when a small grating was presented immediately after the presentation of a large grating (or vice versa), the pupil constriction changed accordingly. In Experiment 3, we replicated Experiment 1 but had the subjects perform an attention-demanding fixation task in one session, and passively view the stimuli in the other. We found that the main effect of task was not significant. In sum, our results show that stimulus size can modulate pupil size robustly and steadily even when the luminance is matched across the different stimuli
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