332 research outputs found

    Radiofrequency catheter ablation in a child with Wolff-Parkinson-White syndrome and congenitally corrected transposition of the great arteries

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    The case is presented of a five-year-old boy with Wolff-Parkinson-White syndrome, who had undergone three surgical palliations because of congenitally corrected transposition of the great arteries, ventricular septal defect and pulmonary trunk near-atresia. Successful and uncomplicated radiofrequency catheter ablation of an accessory pathway located across the systemic atrioventricular valve ring was performed. The procedure was motivated by forthcoming corrective surgery, which would preclude venous access to the heart. This case emphasizes the need for precise timing of ablative therapy in such patients and shows that surgery itself may facilitate catheter ablation. (Cardiol J 2007; 14: 500-503

    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

    Determination of the photodisintegration reaction rates involving charged particles: systematical calculations and proposed measurements based on Extreme Light Infrastructure - Nuclear Physics (ELI-NP)

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    Photodisintegration reaction rates involving charged particles are of relevance to the p-process nucleosynthesis that aims at explaining the production of the stable neutron-deficient nuclides heavier than iron. In this study, the cross sections and astrophysical rates of (g,p) and (g,a) reactions for about 3000 target nuclei with 10<Z<100 ranging from stable to proton dripline nuclei are computed. To study the sensitivity of the calculations to the optical model potentials (OMPs), both the phenomenological Woods-Saxon and the microscopic folding OMPs are taken into account. The systematic comparisons show that the reaction rates, especially for the (g,a) reaction, are dramatically influenced by the OMPs. Thus the better determination of the OMP is crucial to reduce the uncertainties of the photodisintegration reaction rates involving charged particles. Meanwhile, a gamma-beam facility at ELI-NP is being developed, which will open new opportunities to experimentally study the photodisintegration reactions of astrophysics interest. Considering both the important reactions identified by the nucleosynthesis studies and the purpose of complementing the experimental results for the reactions involving p-nuclei, the measurements of six (g,p) and eight (g,a) reactions based on the gamma-beam facility at ELI-NP and the ELISSA detector for the charged particles detection are proposed, and the GEANT4 simulations are correspondingly performed. The minimum required energies of the gamma-beam to measure these reactions are estimated. It is shown that the direct measurements of these photonuclear reactions within the Gamow windows at T_9=2.5 for p-process are fairly feasible and promising at ELI-NP. The expected experimental results will be used to constrain the OMPs of the charged particles, which can eventually reduce the uncertainties of the reaction rates for the p-process nucleosynthesis.Comment: 14 pages, 8 figures, Phys. Rev. C accepte

    Spins, Electromagnetic Moments, and Isomers of 107-129Cd

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    The neutron-rich isotopes of cadmium up to the N=82 shell closure have been investigated by high-resolution laser spectroscopy. Deep-UV excitation at 214.5 nm and radioactive-beam bunching provided the required experimental sensitivity. Long-lived isomers are observed in 127Cd and 129Cd for the first time. One essential feature of the spherical shell model is unambiguously confirmed by a linear increase of the 11/2- quadrupole moments. Remarkably, this mechanism is found to act well beyond the h11/2 shell

    Collinear laser spectroscopy of atomic cadmium

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    Hyperfine structure AA and BB factors of the atomic 5s\,5p\,\; ^3\rm{P}_2 \rightarrow 5s\,6s\,\; ^3\rm{S}_1 transition are determined from collinear laser spectroscopy data of 107123^{107-123}Cd and 111m123m^{111m-123m}Cd. Nuclear magnetic moments and electric quadrupole moments are extracted using reference dipole moments and calculated electric field gradients, respectively. The hyperfine structure anomaly for isotopes with s1/2s_{1/2} and d5/2d_{5/2} nuclear ground states and isomeric h11/2h_{11/2} states is evaluated and a linear relationship is observed for all nuclear states except s1/2s_{1/2}. This corresponds to the Moskowitz-Lombardi rule that was established in the mercury region of the nuclear chart but in the case of cadmium the slope is distinctively smaller than for mercury. In total four atomic and ionic levels were analyzed and all of them exhibit a similar behaviour. The electric field gradient for the atomic 5s\,5p\,\; ^3\mathrm{P}_2 level is derived from multi-configuration Dirac-Hartree-Fock calculations in order to evaluate the spectroscopic nuclear quadrupole moments. The results are consistent with those obtained in an ionic transition and based on a similar calculation.Comment: 12 pages, 5 figure

    Zabieg ablacji prądem o wysokiej częstotliwości u dziecka z zespołem Wolffa-Parkinsona-White&#8217;a oraz wrodzonym skorygowanym przełożeniem wielkich pni tętniczych

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    W niniejszej pracy przedstawiono przypadek kliniczny 5-letniego chłopca chorującego na zespół Wolffa-Parkinsona-White&#8217;a, który dotychczas przeszedł trzy paliatywne operacje kardiochirurgiczne z powodu wrodzonego skorygowanego przełożenia wielkich pni tętniczych, otworu w przegrodzie międzykomorowej oraz niepełnej atrezji pnia płucnego. Wykonano ablację prądem o wysokiej częstotliwości drogi dodatkowej zlokalizowanej w poprzek pierścienia systemowej zastawki przedsionkowo-komorowej. Zabieg przebiegał bez powikłań i zakończył się sukcesem. Czas wykonania zabiegu przyspieszono ze względu na zaplanowany kolejny kardiochirurgiczny zabieg paliatywny, który wykluczyłby dożylny dostęp do jam mięśnia sercowego. Opis tego przypadku podnosi ważną kwestię precyzyjnego określenia czasu wykonania zabiegu ablacyjnego u takich chorych oraz ukazuje fakt, że zabieg kardiochirurgiczny sam w sobie może ułatwić zabieg ablacyjny. (Folia Cardiologica Excerpta 2008; 3: 50-54

    In-beam fast-timing measurements in 103,105,107Cd

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    Fast-timing measurements were performed recently in the region of the medium-mass 103,105,107Cd isotopes, produced in fusion evaporation reactions. Emitted gamma-rays were detected by eight HPGe and five LaBr3:Ce detectors working in coincidence. Results on new and re-evaluated half-lives are discussed within a systematic of transition rates. The 7/21+7/2_1^+ states in 103,105,107Cd are interpreted as arising from a single-particle excitation. The half-life analysis of the 11/2111/2_1^- states in 103,105,107Cd shows no change in the single-particle transition strength as a function of the neutron number
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