513 research outputs found

    Microscopic description of Gamow-Teller transitions in middle pf--shell nuclei by a realistic shell model calculation

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    GT transitions in N=28∼30N=28\sim 30 nuclei are studied in terms of a large-scale realistic shell-model calculation, by using Towner's microscopic parameters. B(GT)B({\rm GT}) values to low-lying final states are reproduced with a reasonable accuracy. Several gross properties with respect to the GT transitions are investigated with this set of the wavefunctions and the operator. While the calculated total GT−^- strengths show no apparent disagreement with the measured ones, the calculated total GT+^+ strengths are somewhat larger than those obtained from charge-exchange experiments. Concerning the Ikeda sum-rule, the proportionality of SGTS_{\rm GT} to (N−Z)(N-Z) persists to an excellent approximation, with a quenching factor of 0.68. For the relative GT−^- strengths among possible isospin components, the lowest isospin component gathers greater fraction than expected by the squared CG coefficients of the isospin coupling. It turns out that these relative strengths are insensitive to the size of model space. Systematics of the summed B(GT)B({\rm GT}) values are discussed for each isospin component.Comment: IOP-LaTeX 23 pages, to appear in J. Phys. G., 5 Postscript figures available upon reques

    Oral health and related factors in a group of children with cystic fibrosis in Istanbul, Turkey

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    Background: Cystic fibrosis (CF) patients can be considered as high caries risk patients because they frequently consume sugar.rich food between meals and they have a high intake of sugar containing syrups, aerosols, and salivary flow reducing medication. Variable caries prevalences were reported in CF patients in previous studies. There are no studies related to CF and salivary thromboplastic activity, which can be presented as a marker of wound healing and bleeding tendency of oral cavity.Objective: The aim of this study was to compare oral health status and salivary pH, flow rate, and thromboplastic activity in children with CF and healthy controls.Materials and Methods: Asample of 35 children with CF (23 girls and 12 boys), and 12 healthy control subjects (6 girls and 6 boys) were selected. Caries experience, oral hygiene, and dental erosion were assessed. Salivary flow rate, pH, thromboplastic activity, and total protein content were determined. Differences between the groups were evaluated using Chi.square test with a significance level set at 0.05.Results: The differences between children with CF and healthy controls in tooth brushing frequency, use of fluoride tablets, caries experience, dental erosion index, oral hygiene index, salivary flow rate and total protein levels were not statistically significant (P > 0.05). Salivary thromboplastic activity of the CF group was significantly lower than the healthy controls (P < 0.01).Conclusion: Large population studies may be necessary to establish the role of salivary thromboplastic activity in children with CF considering our findings related to the decreased salivary thromboplastic activity, which  may indicate delayed oral wound healing process.Key words: Caries, children, cystic fibrosis, saliva, salivary thromboplastic activit

    Morphological evaluation and clinical significance of the supracondylar process and supratrochlear foramen: an anatomic and radiological study

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    Background: In our literature review, we did not encounter any study examining the supracondylar process (SP) and the supratrochlear foramen (STF) with a three-dimensional (3D) reconstruction method. The present study aimed to evaluate SP and STF morphologically by employing the 3D reconstruction method and emphasize their clinical significance. Materials and methods: The research was carried out on dried human humeri of unknown sex and without pathological alterations. A total of 81 humeri (42 right, 39 left) were obtained from the Departments of Anatomy of Gazi University Faculty of Medicine and Lokman Hekim University Faculty of Medicine. The morphometric measurements of SP and STF were made with a digital vernier caliper. The computed tomography (CT) images acquired for radiological evaluation were analyzed with the 3D reconstruction method. Results: The narrower distal medullary canal widths of humeri with STF were found to be statistically significant. No statistically significant difference was found between the transverse diameters (TD), vertical diameters (VD), the distance of the medial edge to the medial epicondyle (ME), and the distance of the lateral edge to the lateral epicondyle (LE) of the supratrochlear foramen of the right and left humeri. Conclusions: The supracondylar process is often evaluated by mistake as a pathological condition of the bone, not as a normal anatomical variation. Knowing different shapes and dimensions, e.g., the TD and VD distance in which STF emerges, can assist in avoiding the misinterpretation of radiographs

    Impact of obstructive sleep apnea on the occurrence of restenosis after elective percutaneous coronary intervention in ischemic heart disease

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    <p>Abstract</p> <p>Rationale</p> <p>There is growing evidence that obstructive sleep apnea is associated with coronary artery disease. However, there are no data on the course of coronary stenosis after percutaneous coronary intervention in patients with obstructive sleep apnea.</p> <p>Objectives</p> <p>To determine whether sleep apnea is associated with increased late lumen loss and restenosis after percutaneous coronary intervention.</p> <p>Methods</p> <p>78 patients with coronary artery disease who underwent elective percutaneous coronary intervention were divided in 2 groups: 43 patients with an apnea hypopnea – Index < 10/h (group I) and 35 pt. with obstructive sleep apnea and an AHI > 10/h (group II). Late lumen loss, a marker of restenosis, was determined using quantitative coronary angiography after 6.9 ± 3.1 months.</p> <p>Main results</p> <p>Angiographic restenosis (>50% luminal diameter), was present in 6 (14%) of group I and in 9 (25%) of group II (p = 0.11). Late lumen loss was significant higher in pt. with an AHI > 10/h (0.7 ± 0.69 mm vs. 0.38 ± 0.37 mm, p = 0.01). Among these 35 patients, 21(60%) used their CPAP devices regularly. There was a marginally lower late lumen loss in treated patients, nevertheless, this difference did not reach statistical significance (0.57 ± 0.47 mm vs. 0.99 ± 0.86 mm, p = 0.08). There was no difference in late lumen loss between treated patients and the group I (p = 0.206).</p> <p>Conclusion</p> <p>In summary, patients with OSA and coronary artery disease have a higher degree of late lumen loss, which is a marker of restenosis and vessel remodeling after elective percutaneous intervention.</p

    First decay study of the very neutron-rich isotope Br-93

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    The decay of the mass-separated, very neutron-rich isotope Br-93 has been studied by gamma-spectroscopy. A level scheme of its daughter Kr-93 has been constructed. Level energies, gamma-ray branching ratios and multipolarities suggest spins and parities which are in accord with a smooth systematics of the N=57 isotones for Z less-equal 40, suggesting the N=56 shell closure still to be effective in Kr isotopes. So far, there is no indication of a progressive onset of deformation in neutron-rich Kr isotopes.Comment: 17 pages, 3 figures, Phys. Rev. C, in prin

    A robust Logistics-Electric framework for optimal power management of electrified ports under uncertain vessel arrival time

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    \ua9 2024Maritime transport is responsible for producing a considerable amount of environmental pollution due to the reliance of ports and ships on the carbon-based energy sources. With the increasing trend towards port electrification to reduce carbon emissions, the operation of ports will be increasingly relying on the electricity network. This interconnection creates multiple challenges due to the complexity of power flow in the port network, uncertainty of vessel arrival time and fluctuation of power generation of renewable energy sources. These uncertainties can lead to an overload in electricity networks and delays in cargo-handling activities, resulting in increased vessel handling times and environmental emissions. This paper presents a joint logistics-electric framework for optimal operation and power management of electrified ports, considering multiple uncertainties in the arrival time of vessels, network demand, and renewable power generation. An optimal power flow method is developed for a real-life port, with consideration for multiple port logistic assets such as cargo handling equipment, reefers, and renewable energy sources. The proposed model ensures feasible port operation for all uncertainty realisations defined by robust optimisation, while minimising operational costs. Simulation results demonstrate that the probability of a network constraint violation can be as high as 70% for an electrified major UK port if the uncertainty in the port operation is neglected, presenting an unacceptable risk of disruption to port activities. Furthermore, such uncertainty can cause 150% increase in emissions if the ships use their auxiliary engine instead of using shore power. The numerical study shows that such challenges can be handled by a 0.3% increase in the robustness in face of uncertainty, while the cost increase in the worst case does not exceed 4.7%. This shows the effectiveness of the proposed method enhancing robustness against uncertainty at the minimum cost

    Quadrupole and Hexadecapole Correlations in Rotating Nuclei Studied within the Single-j Shell Model

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    The influence of quadrupole and hexadecapole residual interactions on rotational bands is investigated in a single-j shell model. An exact shell-model diagonalization of quadrupole-plus-hexadecapole interaction can sometimes produce a staggering of energy levels in the yrast bands.Comment: 15 pages, 9 Postscript figures, REVTEX, to be published in PR

    Transition energy and lifetime for the ground state hyperfine splitting of high Z lithiumlike ions

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    The ground state hyperfine splitting values and the transition probabilities between the hyperfine structure components of high Z lithiumlike ions are calculated in the range Z=49−83Z=49-83. The relativistic, nuclear, QED and interelectronic interaction corrections are taken into account. It is found that the Bohr-Weisskopf effect can be eliminated in a combination of the hyperfine splitting values of the hydrogenlike and lithiumlike ions of an isotope. This gives a possibility for testing the QED effects in a combination of the strong electric and magnetic fields of the heavy nucleus. Using the experimental result for the 1s1s hyperfine splitting in ^{209}Bi^{82+}, the 2s hyperfine splitting in ^{209}Bi^{80+} is calculated to be \Delta E=0.7969(2) eV.Comment: The nuclear charge distribution correction \delta is corrected, 14 pages, Late
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