725 research outputs found

    Precision Measurement of 11Li moments: Influence of Halo Neutrons on the 9Li Core

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    The electric quadrupole moment and the magnetic moment of the 11Li halo nucleus have been measured with more than an order of magnitude higher precision than before, |Q| = 33.3(5)mb and mu=3.6712(3)mu_N, revealing a 8.8(1.5)% increase of the quadrupole moment relative to that of 9Li. This result is compared to various models that aim at describing the halo properties. In the shell model an increased quadrupole moment points to a significant occupation of the 1d orbits, whereas in a simple halo picture this can be explained by relating the quadrupole moments of the proton distribution to the charge radii. Advanced models so far fail to reproduce simultaneously the trends observed in the radii and quadrupole moments of the lithium isotopes.Comment: 4 pages, 4 figures, 1 tabl

    A new beamline for laser spin-polarization at ISOLDE

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    A beamline dedicated to the production of laser-polarized radioactive beams has been constructed at ISOLDE, CERN. We present here different simulations leading to the design and construction of the setup, as well as technical details of the full setup and examples of the achieved polarizations for several radioisotopes. Beamline simulations show a good transmission through the entire line, in agreement with observations. Simulations of the induced nuclear spin-polarization as a function of atom-laser interaction length are presented for 26,28^{26,28}Na, [1] and for 35^{35}Ar, which is studied in this work. Adiabatic spin rotation of the spin-polarized ensemble of atoms, and how this influences the observed nuclear ensemble polarization, are also performed for the same nuclei. For 35^{35}Ar, we show that multiple-frequency pumping enhances the ensemble polarization by a factor 1.85, in agreement with predictions from a rate equations model. [1] J. Phys. G: Nucl. Part. Phys./174408400

    Ground-State Electromagnetic Moments of Calcium Isotopes

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    High-resolution bunched-beam collinear laser spectroscopy was used to measure the optical hyperfine spectra of the 4351^{43-51}Ca isotopes. The ground state magnetic moments of 49,51^{49,51}Ca and quadrupole moments of 47,49,51^{47,49,51}Ca were measured for the first time, and the 51^{51}Ca ground state spin I=3/2I=3/2 was determined in a model-independent way. Our results provide a critical test of modern nuclear theories based on shell-model calculations using phenomenological as well as microscopic interactions. The results for the neutron-rich isotopes are in excellent agreement with predictions using interactions derived from chiral effective field theory including three-nucleon forces, while lighter isotopes illustrate the presence of particle-hole excitations of the 40^{40}Ca core in their ground state.Comment: Accepted as a Rapid Communication in Physical Review

    Magnetic Moment of the Fragmentation Aligned 61Fe(9/2)+ Isomer

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    We report on the g factor measurement of the isomer in 61Fe^{61}Fe (E=861keVE^{*}=861 keV). The isomer was produced and spin-aligned via a projectile-fragmentation reaction at intermediate energy, the Time Dependent Perturbed Angular Distribution (TDPAD) method being used for the measurement of the g factor. For the first time, due to significant improvements of the experimental technique, an appreciable residual alignment of the isomer has been observed, allowing a precise determination of its g factor: g=0.229(2)g=-0.229(2). Comparison of the experimental g factor with shell-model and mean field calculations confirms the 9/2+9/2^+ spin and parity assignments and suggests the onset of deformation due to the intrusion of Nilsson orbitals emerging from the νg9/2\nu g_{9/2}.Comment: 4 figures. Submitted to Phys. Rev. Let

    Arginine-enriched oral nutritional supplementation in the treatment of pressure ulcers: A literature review

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    Abstract Purpose Pressure ulcers are a common, potentially mortal complication to disease, care and treatment for patients of all ages with mobility impairments. In addition, pressure ulcers not always heal straightforward because of multiple intrinsic factors e.g. undernutrition and extrinsic factors e.g. inadequate nutrition that may influence the healing process. The aim of this descriptive review is to investigate the treatment effect of arginine-enriched oral nutritional supplementation in pressure ulcers. Results The included studies, seven RCTs and four CTs, were published between January 2001 and October 2015, and conducted in different settings: hospital, long-term care/care homes and home care. The duration of follow-up of the studies varied from 2 weeks to complete healing and the sample size varied from 16 to 245 patients aged from 37 to 92 years and with pressure ulcer stages II, III or IV. The wound-specific oral nutritional supplementation contained 3–9 g of arginine. The main outcome measures were complete healing, time needed for complete wound closure, reduction in wound surface area, nursing time, and the number of dressings used. Ten out of eleven studies showed a beneficial effect of the arginine-enriched oral nutritional supplementation on the healing of pressure ulcers. Conclusions This review shows that there is substantial evidence supporting the positive effect of nutritional supplementation with additional protein, arginine and micronutrients to promote pressure ulcer healing. Currently, there is only one large study (N = 200) with level 1 evidence. It may be postulated that at least one extra comparable level 1 study is needed to draw firm conclusions on the importance of key nutrients in complete pressure ulcer healing

    Nuclear spins, magnetic moments and quadrupole moments of Cu isotopes from N = 28 to N = 46: probes for core polarization effects

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    Measurements of the ground-state nuclear spins, magnetic and quadrupole moments of the copper isotopes from 61Cu up to 75Cu are reported. The experiments were performed at the ISOLDE facility, using the technique of collinear laser spectroscopy. The trend in the magnetic moments between the N=28 and N=50 shell closures is reasonably reproduced by large-scale shell-model calculations starting from a 56Ni core. The quadrupole moments reveal a strong polarization of the underlying Ni core when the neutron shell is opened, which is however strongly reduced at N=40 due to the parity change between the pfpf and gg orbits. No enhanced core polarization is seen beyond N=40. Deviations between measured and calculated moments are attributed to the softness of the 56Ni core and weakening of the Z=28 and N=28 shell gaps.Comment: 13 pagers, 19 figures, accepted by Physical Review
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