130 research outputs found

    High lying E0 strength in C-12

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    Journals published by the American Physical Society can be found at http://publish.aps.org/The excitation region in C-12 from 7 MeV<E-x<60 MeV was studied with inelastic scattering of 240-MeV alpha particles at small angles including 0 degrees where E0 strength is enhanced. The strengths of known 0(+) states at E-x = 7.655 MeV and E-x = 10.3 MeV were obtained and E0 strength was observed to be distributed between E-x = 14 MeV and E-x = 30 MeV with a centroid of 21.5 +/- 0.4 MeV and an ms width of 3.1 +/- 0.2 MeV containing 14.5 +/- 4.0% of the isoscalar E0 energy-weighted sum rule. Angular distributions and strengths of the E-x =4.439 MeV 2(+), 9.641 MeV 3(-), and 10.844 MeV 1(-) states were also obtained. [S0556-2813(98)05704-5]

    Combined simultaneous transcranial and transsphenoidal resection of large-to-giant pituitary adenomas

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    Background: While large-to-giant pituitary adenomas (PAs) may be safely removed by experienced surgeons through a single route, the procedure is technically challenging. We present the outcome of a simultaneous combined transcranial and transsphenoidal approach and discuss its applications. Methods: A retrospective review was conducted on 12 consecutive patients. Surgical complications, visual and endocrinological functions, and tumour control were reviewed. Results: There were four men and eight women, with a mean age of 47.6 years. All but one patient had non-functioning PAs. The mean tumour height was 4.1 cm (range: 2.3-5.5). The predominant presenting symptoms were visual field loss in eight patients, headache in three patients and mental confusion in one patient. There was no operative mortality. Post-operative cerebrospinal fluid leakage occurred in one patient. Five of the eight patients who presented with visual field loss achieved full recovery, and three had partial improvement. Two patients developed permanent diabetes insipidus after surgery. Panhypopituitarism occurred in one patient. Gross total removal (GTR) was achieved in five, and subtotal removal (STR) in seven patients. Seven patients received post-operative external irradiation. All patients who had GTR remained tumour-free and all those with STR had stable diseases after a mean follow-up period of 53.1 months (range: 14.1-92.1). Conclusion: The simultaneous 'above and below' approach is a safe and effective surgical strategy for large-to-giant PAs, particularly when expertise in endoscopic transsphenoidal surgery is unavailable. Its use, however, should be limited to a carefully selected group of patients, and tailored to individual user's expertise and experience. © 2011 The Author(s).published_or_final_versio

    Sequential approaches for resection of clival chordoma

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    Free Paper 7Conference Theme: Degenerative Lumbar SpineINTRODUCTION: Chordomas are extra-axial tumours that originate from the primitive notochord. They are rare diseases that present mostly between the third and the fifth decades of life with an incidence rate of 0.08 per 100,000 in the United States. Approximately 35% of chordomas arise in the clivus of the skull base (clival chordoma). In spite of their slow-growing and non-malignant histopathological appearance, they are potentially life threatening due to their locally destructive and invasive nature. Clival chordomas are located near the spheno-occipital junction at the base of the skull, behind the sphenoid sinuses. Involvement of the surrounding cranial nerves accounts for their symptomatology. It is notorious for its high tendency of recurrence following treatment, with a reported recurrence rate of 68%. Therefore, gross total resection in combination with adjuvant radiotherapy is the standard mode of treatment …published_or_final_versio

    Monopole Strength in Ni-58

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    Journals published by the American Physical Society can be found at http://publish.aps.org/Differential cross-section data from 0-degrees to 8-degrees for inelastic scattering of 129 MeV alpha particles exciting Ni-58 in the region of 14-22 MeV have been analyzed to explore the existence of monopole strength at approximately E(x) = 17 MeV. The angular distribution for a peak at E(x) = 17.0 MeV with GAMMA = 4.0 MeV is consistent with an E0 transition exhausting 19 +/- 10% of the E0 energy-weighted sum rule (EWSR). The angular distributions for peaks at E(x) = 16.1 and 20.4 MeV with GAMMA = 4.7 and 4.4 MeV, respectively, were fit by 52 +/- 10% of the E2 EWSR and a combination of E2 (6.9 +/- 2.0 EWSR) and E0 (2.9(-2.9)+2.1% EWSR)

    Isoscalar giant resonances in Si-28 and the mass dependence of nuclear compressibility

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    Journals published by the American Physical Society can be found at http://publish.aps.org/The giant resonance region from 8 MeV < E-x < 55 MeV in Si-28 has been studied with inelastic scattering of 240 MeV alpha particles at small angles including 0degrees. Strength corresponding to 81 +/- 10%, 68 +/- 9%, and 15 +/-4% of the isoscalar E0, E2, and E1 sum rules, respectively, was identified with centroids of 21.25 +/-0.38 MeV, 18.54 +/- 0.25 MeV, 19.15 +/- 0.60 MeV, and rms widths of 6.4 +/- 0.6 MeV, 4.7 +/- 0.6 MeV, and 6.9 +/- 0.7 MeV. The mass dependence of the compression modulus of finite nuclei is shown to be reasonably well reproduced from A = 24 to 208 in relativistic mean field calculations with the NLC interaction having K-nm 5225 MeV and in nonrelativistic calculations with the RATP interaction having K-nm 5240 MeV

    Isoscalar electric multipole strength in C-12

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    Journals published by the American Physical Society can be found at http://publish.aps.org/The excitation region in C-12 below E-x=45 MeV was studied using 240 MeV alpha-particle scattering. Elastic scattering was measured from theta(c.m.)=3.8degrees to 49.4degrees and density dependant folding optical model parameters were obtained. Inelastic scattering to the 4.44 MeV 2(+), 7.65 MeV 0(+), 9.64 MeV 3(-), 10.3 MeV 0(+), and 10.84 MeV 1(-) states was measured and B(EL) values obtained. Inelastic scattering exciting C-12 to 10 MeVless than or equal toE(x)less than or equal to12.5 MeV was measured from 1.4degreesless than or equal totheta(c.m.)less than or equal to10degrees and to 12.5 MeVless than or equal toE(x)less than or equal to45 MeV from 1.4degreesless than or equal totheta(c.m.)less than or equal to16degrees and E0, E1, E2, and E3 strength distributions were obtained. Strength was identified corresponding to 27+/-5, 78+/-9, and 51+/-7% of the isoscalar E0, E1, and E2 energy weighted sum rule (EWSR), respectively, with centroids of 21.9+/-0.3, 27.5+/-0.4, and 22.6+/-0.5 MeV and rms widths of 4.8+/-0.5, 7.6+/-0.6, and 6.8+/-0.6 MeV. Less than 7% of the E3 EWSR strength was identified

    Splitting of the giant monopole and quadrupole resonances in Sm-154

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    Journals published by the American Physical Society can be found at http://publish.aps.org/Strength functions for the isoscalar giant monopole and quadrupole resonances in Sm-154 have been measured with inelastic scattering of 240 MeV alpha particles at small angles. The E0 strength distribution containing (104(-20)(+15))% of the energy-weighted sum rule (EWSR) is consistent with two peaks at E-x = 12.1 +/- 0.4 MeV and 15.5 +/- 0.3 MeV containing (36 +/- 10)% and (68 /- 9)% of the EWSR and the E2 strength distribution containing (103(-20)(+18))% of the EWSR is consistent with three peaks at E-x = 11.3 +/- 0.2 MeV, 14.5 +/- 0.5 MeV, and 17.5 +/- 0.5 MeV containing (44 +/- 7)%, (44 +/- 8)%, and (15 +/- 8)%, respectively, of the EWSR. [S0556-2813(99)04812-8]

    Oral health status of asthmatic preschoolers in Hong Kong

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    Giant Quadrupole-Resonance in Ni Isotopes

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    Journals published by the American Physical Society can be found at http://publish.aps.org/Inelastic scattering of 129 MeV alpha particles has been used to excite the giant quadrupole resonance in Ni-58, Ni-60, Ni-62, Ni-64. The resonance was found to exhaust 58 +/- 12%, 76 +/- 14%, 78 +/- 14%, and 90 +/-16% of the E2 energy-weighted sum rule, respectively, for Ni-58, Ni-60, Ni-62, Ni-64

    Coulomb-Excitation of the Giant-Dipole Resonance in Light-Ion Inelastic-Scattering from Pb-208

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    Journals published by the American Physical Society can be found at http://publish.aps.org
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