8,896 research outputs found

    Nilsson-SU3 selfconsistency in heavy N=Z nuclei

    Get PDF
    It is argued that there exist natural shell model spaces optimally adapted to the operation of two variants of Elliott' SU3 symmetry that provide accurate predictions of quadrupole moments of deformed states. A selfconsistent Nilsson-like calculation describes the competition between the realistic quadrupole force and the central field, indicating a {\em remarkable stability of the quadruplole moments}---which remain close to their quasi and pseudo SU3 values---as the single particle splittings increase. A detailed study of the N=ZN=Z even nuclei from 56^{56}Ni to 96^{96}Cd reveals that the region of prolate deformation is bounded by a pair of transitional nuclei 72^{72}Kr and 84^{84}Mo in which prolate ground state bands are predicted to dominate, though coexisting with oblate ones,Comment: Replacement I) Title simplified. II) Major revision: structure of paper kept but two thirds totally rewritten (same number of pages); 20 references adde

    Excitation of the GDR and the Compressional Isoscalar Dipole State by alpha scattering

    Full text link
    The excitation of the isovector giant dipole resonance (GDR) by alpha scattering is investigated as a method of probing the neutron excess in exotic nuclei. DWBA calculations are presented for 28O and 70Ca and the interplay of Coulomb and nuclear excitation is discussed. Since the magnitude of the Coulomb excitation amplitude is strongly influenced by the Q-value, the neutron excess plays an important role, as it tends to lower the energy of the GDR. The excitation of the compressional isoscalar dipole state in 70Ca by alpha scattering is also investigated. It is shown that the population of this latter state may be an even more sensitive probe of the neutron skin than the isovector GDR.Comment: 7 pages, 5 figures, Latex2

    Are the therapeutic strategies in anorexia of ageing effective on nutritional status? A systematic review with meta-analysis

    Get PDF
    BACKGROUND: Anorexia of ageing (AA) may be considered as a risk factor for frailty and has an important impact on quality of life, morbidity and mortality. METHODS: A systematic review and a meta-analysis were performed to summarise the results from several trials on the effectiveness of treatments in AA, as associated with depression, sensory impairment of taste and smell, decreased appetite or early satiety, and disability. Eligible studies were required to report baseline and follow-up values, the mean change (∆-change) from baseline, and/or the mean difference among intervention groups versus control group, concerning food intake (kcal/daily) and/or nutritional outcomes, such as body weight, body mass index, albumin and Mini Nutritional Assessment. RESULTS: The systematic review included 20 papers based on different therapeutic approaches concerning food intake and/or nutritional outcomes. The results of the meta-analysis indicate that the interventions for AA have an important impact on body weight [+1.59 kg; 95% confidence interval (CI) = 1.48-+1.71 kg; P < 0.001) and on energy intake (+56.09 kcal; 95% CI = -54.05 to +166.25 kcal; P = 0.32). Regarding secondary outcomes, it was not possible to meta-analyse the limited amount of data availab le. CONCLUSIONS: The different variants of AA need to be defined because diverse therapeutic approaches are available. A more precise definition of the functional impairments associated with AA may allow a more correct decision about the most appropriate therapy to be prescribed. Moreover, this may allow for a more effective performance of the different therapeutic approaches once they are better targeted to the different scenarios of AA

    The population of deformed bands in 48^{48}Cr by emission of 8^{8}Be from the 32^{32}S + 24^{24}Mg reaction

    Full text link
    Using particle-γ\gamma coincidences we have studied the population of final states after the emission of 2 α\alpha-particles and of 8^{8}Be in nuclei formed in 32^{32}S+24^{24}Mg reactions at an energy of EL(32S)=130MeV\textrm{E}_{\rm L}(^{32}\textrm{S}) = 130 {\rm MeV}. The data were obtained in a setup consisting of the GASP γ\gamma-ray detection array and the multidetector array ISIS. Particle identification is obtained from the Δ\DeltaE and E signals of the ISIS silicon detector telescopes, the 8^{8}Be being identified by the instantaneous pile up of the Δ\DeltaE and E pulses. γ\gamma-ray decays of the 48^{48}Cr nucleus are identified with coincidences set on 2 α\alpha-particles and on 8^{8}Be. Some transitions of the side-band with Kπ=4−K^\pi=4^{-} show stronger population for 8^{8}Be emission relative to that of 2 α\alpha-particles (by a factor 1.5−1.81.5-1.8). This observation is interpreted as due to an enhanced emission of 8^{8}Be into a more deformed nucleus. Calculations based on the extended Hauser-Feshbach compound decay formalism confirm this observation quantitatively.Comment: 17 pages, 9 figures accepted for publication in J. Phys.

    Isospin-breaking interactions studied through mirror energy differences

    Get PDF
    Background: Information on charge-dependent (i.e., isospin-non-conserving) interactions is extracted from excited states of mirror nuclei. Purpose: Specifically, the purpose of the study is to extract effective isovector (Vpp 12Vnn) interactions which, in general, can either be of Coulomb or nuclear origin. Methods: A comprehensive shell-model description of isospin-breaking effects is used to fit data on mirror energy differences in the A = 42\u201354 region. The angular-momentum dependence of isospin-breaking interactions was determined from a systematic study of mirror energy differences. Results: The results reveal a significant isovector term, with a very strong spin dependence, beyond that expected of a two-body Coulomb interaction. Conclusions: The isospin-breaking terms that are extracted have a J dependence that is not consistent with the known CSB properties of the bare nucleon-nucleon interaction

    Probing new physics in diphoton production with proton tagging at the Large Hadron Collider

    Get PDF
    The sensitivities to anomalous quartic photon couplings at the Large Hadron Collider are estimated using diphoton production via photon fusion. The tagging of the protons proves to be a very powerful tool to suppress the background and unprecedented sensitivities down to 6⋅10−156 \cdot 10^{-15}\gev−4^{-4} are obtained, providing a new window on extra dimensions and strongly-interacting composite states in the multi-TeV range. Generic contributions to quartic photon couplings from charged and neutral particles with arbitrary spin are also presented.Comment: 4 pages, 3 figure

    On the dynamics of bubbles in boiling water

    Full text link
    We investigate the dynamics of many interacting bubbles in boiling water by using a laser scattering experiment. Specifically, we analyze the temporal variations of a laser intensity signal which passed through a sample of boiling water. Our empirical results indicate that the return interval distribution of the laser signal does not follow an exponential distribution; contrariwise, a heavy-tailed distribution has been found. Additionally, we compare the experimental results with those obtained from a minimalist phenomenological model, finding a good agreement.Comment: Accepted for publication in Chaos, Solitons & Fractal
    • …
    corecore