153 research outputs found

    Spectroscopy of 230Th in the (p,t) reaction

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    The excitation spectra in the deformed nucleus 230Th were studied by means of the (p,t) reaction, using the Q3D spectrograph facility at the Munich Tandem accelerator. The angular distributions of tritons are measured for about 200 excitations seen in the triton spectra up to 3.3 MeV. Firm 0+ assignments are made for 16 excited states by comparison of experimental angular distributions with the calculated ones using the CHUCK code. Additional assignments are possible: relatively firm for 4 states and tentative also for 4 states. Assignments up to spin 6+6^+ are made for other states. Sequences of the states are selected which can be treated as rotational bands and as multiplets of excitations. Experimental data are compared with interacting boson model IBM) and quasiparticle-phonon model (QPM) calculations.Comment: 35 pages in PDF, 14 figures in text and 8 figures in appendix Extended version of the paper published in Phys.Re

    Superdeformed rotational bands in Pu-240

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    The intermediate structure of the fission resonances has been observed in Pu-240. A resonance structure found around the excitation energy of 4.5 MeV was interpreted as a group of K-pi = 0(+) superdeformed rotational bands. The moments of inertia and level density distributions were also deduced for the individually observed band-heads

    Modern agglutinated foraminifera from the Hovgård ridge, fram strait, west of Spitsbergen: Evidence for a deep bottom current

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    Deep-water agglutinated foraminifera on the crest of the Hovgârd Ridge, west of Spitsbergen, consist mostly of large tubular astrorhizids. At a boxcore station collected from the crest of Hovgârd Ridge at a water depth of 1169 m, the sediment surface was covered with patches of large (1 mm diameter) tubular forms, belonging mostly to the species Astrorhiza crassatina Brady, with smaller numbers of Saccorhiza, Hyperammina, and Psammosiphonella. Non-tubutar species consisted mainly of opportunistic forms, such as Psammosphaera and Reophax. The presence of large suspension-feeding tubular genera as well as opportunistic forms point to the presence of deep currents at this locality that are strong enough to disturb the benthic fauna. This is confirmed by data obtained from sediment echosounding, which exhibit lateral variation in relative sedimentation rates within the Pleistocene sedimentary drape covering the ridge, indicative of winnowing in a south-easterly direction

    Resonant tunneling through the triple-humped fission barrier of U-236

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    The fission probability of U-236 as a function of the excitation energy has been measured with high energy resolution using the U-235(d, pf) reaction in order to study hyperdeformed (HD) rotational bands. Rotational band structures with a moment of inertia of theta = 217 +/- 38 h(2)/MeV have been observed, corresponding to hyperdeformed configurations. From the level density of the rotational bands the excitation energy of the ground state in the third minimum was determined to be 2.7 +/- 0.4 MeV. The excitation energy of the lowest hyperdeformed transmission resonance and the energy dependence of the fission isomer population probability enabled the determination of the height of the inner fission barrier E-A = 5.05 +/- 0.20 MeV and its curvature parameter h omega(A) = 1.2 MeV. Using this new method the long-standing uncertainties in determining the height of the inner potential barrier in uranium isotopes could be resolved. (c) 2005 Elsevier B.V. All rights reserved

    On the excitation energy of the ground state in the third minimum of U-234

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    The U-233(d,pf)U-234 reaction has been studied with high energy resolution. The observed fission resonances in the excitation energy range of 4.75 less than or equal to E* less than or equal to 5.40 MeV were described as members of rotational bands with rotational parameters characteristic to the hyperdeformed nuclear shape ((h) over bar(2)/2 theta = 2.1 +/- 0.2 keV). Information on the K values of the bands has been obtained from fission fragment angular distribution measurements. The level density of the most strongly excited J = 3 states has been compared to the prediction of the back-shifted Fermi-gas formula and the energy of the ground state in the third minimum has been estimated to be E-III = 3.1 +/- 0.4 Me

    Specialist laboratory networks as preparedness and response tool - The emerging viral diseases-expert laboratory network and the chikungunya outbreak, Thailand, 2019

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    We illustrate the potential for specialist laboratory networks to be used as preparedness and response tool through rapid collection and sharing of data. Here, the Emerging Viral Diseases-Expert Laboratory Network (EVD-LabNet) and a laboratory assessment of chikungunya virus (CHIKV) in returning European travellers related to an ongoing outbreak in Thailand was used for this purpose. EVD-LabNet rapidly collected data on laboratory requests, diagnosed CHIKV imported cases and sequences generated, and shared among its members and with the European Centre for Disease Prevention and Control. Data across the network showed an increase in CHIKV imported cases during 1 October 2018-30 April 2019 vs the same period in 2018 (172 vs 50), particularly an increase in cases known to be related to travel to Thailand (72 vs 1). Moreover, EVD-LabNet showed that strains were imported from Thailand that cluster with strains of the ECSA-IOL E1 A226 variant emerging in Pakistan in 2016 and involved in the 2017 outbreaks in Italy. CHIKV diagnostic requests increased by 23.6% between the two periods. The impact of using EVD-LabNet or similar networks as preparedness and response tool could be improved by standardisation of the collection, quality and mining of data in routine laboratory management systems
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