Coulomb-excitation experiments to study electromagnetic properties of radioactive even-even Hg isotopes were performed with 2.85 MeV/nucleon mercury beams from REX-ISOLDE. Magnitudes and relative ...signs of the reduced E2 matrix elements that couple the ground state and low-lying excited states in Hg182-188 were extracted. Information on the deformation of the ground and the first excited 0+ states was deduced using the quadrupole sum rules approach. Results show that the ground state is slightly deformed and of oblate nature, while a larger deformation for the excited 0+ state was noted in Hg182,184. The results are compared to beyond mean field and interacting-boson based models and interpreted within a two-state mixing model. Partial agreement with the model calculations was obtained. The presence of two different structures in the light even-mass mercury isotopes that coexist at low excitation energy is firmly established.
Distant metastases frequently occur in gastroenteropancreatic neuroendocrine tumors. If hepatic surgery is not feasible, patients are treated with somatostatin analogs. However, the underlying ...mechanisms of action of this treatment remain to be defined. The aim of the present study was to analyze the micro-RNA expression profile inter-individually before and after the treatment with somatostatin analogs.
Tumor specimens of all included patients (n = 8) before and after the onset of a therapy with somatostatin analogs were analyzed and a micro-RNA expression profile (754 micro-RNAs) of each probe was generated. This analysis in an intra-individual setting was selected to avoid bias from inter-individual differences. The micro-RNA expression profiles were validated by qPCR. Patients with any other systemic treatment were excluded from the present study.
Eight patients were included in the present study of which all had neuroendocrine tumors of the small intestine with diffuse hepatic metastases. Grouped analyses revealed that 15 micro-RNAs were differentially expressed (3 up- and 12 downregulated) after the exposure to somatostatin analogs. Additionally, let-7c-5p and mir-3137 are concordantly regulated in the inter-individually analysis.
This is the first study analyzing the individual micro-RNA expression profile before and after a therapy with somatostatin analogs. Data from this study reveal that somatostatin analogs may in part exert their beneficial effects through an alteration in the micro-RNA expression profile.
When performing multi-component significance tests with multiply-imputed datasets, analysts can use a Wald-like test statistic and a reference F-distribution. The currently employed degrees of ...freedom in the denominator of this F-distribution are derived assuming an infinite sample size. For modest complete-data sample sizes, this degrees of freedom can be unrealistic; for example, it may exceed the complete-data degrees of freedom. This paper presents an alternative denominator degrees of freedom that is always less than or equal to the complete-data denominator degrees of freedom, and equals the currently employed denominator degrees of freedom for infinite sample sizes. Its advantages over the currently employed degrees of freedom are illustrated with a simulation.
New physics opportunities are opening up by the Advanced Gamma Tracking Array, AGATA, as it evolves to the full 4
π
instrument. AGATA is a high-resolution
γ
-ray spectrometer, solely built from ...highly segmented high-purity Ge detectors, capable of measuring
γ
rays from a few tens of keV to beyond 10 MeV, with unprecedented efficiency, excellent position resolution for individual
γ
-ray interactions, and very high count-rate capability. As a travelling detector AGATA will be employed at all major current and near-future European research facilities delivering stable and radioactive ion beams.
Agata characterisation and pulse shape analysis Boston, A. J.; Crespi, F. C. L.; Duchêne, G. ...
The European physical journal. A, Hadrons and nuclei,
09/2023, Letnik:
59, Številka:
9
Journal Article
Recenzirano
Odprti dostop
The AGATA and GRETA spectrometers are large arrays of highly segmented HPGe detectors that use the technique of gamma ray tracking to reconstruct the scattering path of gamma rays interacting within ...the active material. A basic requirement is a precise reconstruction of the individual interaction locations within the detectors. This is possible through the use of pulse shape analysis which has to be conducted in real time due to the high data rates generated by the spectrometer. The methodologies that have been evaluated to perform this for AGATA are discussed along with the approaches used to calculate the pulse shape databases required by these algorithms. Finally, the performance and limitations of the existing approaches are reviewed.
The Advanced GAmma Tracking Array (AGATA) is a next generation high-resolution γ-ray spectrometer for nuclear structure studies based on the principle of γ-ray tracking. It is built from high-fold ...segmented germanium detectors which will operate in position-sensitive mode by employing digital electronics and pulse-shape decomposition algorithms. The unique combination of highest detection efficiency and position sensitivity allows spectroscopic studies with instable ion beams of lowest intensity. The first implementation of the array consisted of five AGATA modules; it was operated at INFN Legnaro. A larger array of AGATA modules was used at GSI for experiments with unstable ion beams at relativistic energies. At the moment the spectrometer is hosted by GANIL. In the near future AGATA will be employed at the leading infrastructures for nuclear structure studies in Europe. The presentation will illustrate the potential of the novel gamma-ray tracking method by physics cases from the different exploitation sites. Perspectives and opportunities for γ-ray spectroscopy at future radioactive ion beam facilities are presented and discussed.
When statistical agencies release microdata to the public, malicious users (intruders) may be able to link records in the released data to records in external databases. Releasing data in ways that ...fail to prevent such identifications may discredit the agency or, for some data, constitute a breach of law. To limit disclosures, agencies often release altered versions of the data; however, there usually remain risks of identification. This article applies and extends the framework developed by Duncan and Lambert for computing probabilities of identification for sampled units. It describes methods tailored specifically to data altered by recoding and topcoding variables, data swapping, or adding random noise (and combinations of these common data alteration techniques) that agencies can use to assess threats from intruders who possess information on relationships among variables and the methods of data alteration. Using data from the Current Population Survey, the article illustrates a step-by-step process for evaluating identification disclosure risks for competing releases under varying assumptions of intruders' knowledge. Risk measures are presented for individual units and for entire datasets.
Coulomb excitation of Zn74,76 Illana, A.; Zielińska, M.; Huyse, M. ...
Physical review. C,
10/2023, Letnik:
108, Številka:
4
Journal Article
Recenzirano
Odprti dostop
The first experiment using radioactive beams post-accelerated by the HIE-ISOLDE facility has enabled to obtain a precise set of B(E2)transition probabilities in neutron-rich Zn74,76 isotopes. The ...resulting B(E2; 2+1→0+1) values are consistent with those determined in earlier REX-ISOLDE measurements. While the B(E2; 4+1→2+1) transition probability in Zn76 is also in agreement with earlier Coulomb-excitation results, the value obtained for Zn74 is considerably lower. For the first time, a spectroscopic quadrupole moment of the 2+1 state was measured for an exotic nucleus in this mass region. A detailed comparison is presented with large-scale shell-model and Monte Carlo shell-model calculations.
Lifetime measurements of excited states in doubly-magic 56Ni have been performed exploiting the Doppler-shift attenuation method in order to determine reduced transition probabilities. For the 41+ ...and 61+ states, the deduced B(E2) values are compared with results from shell-model calculations employing the GXPF1A and the modern PFSDG-U interactions. In addition, valence ab-initio calculations were performed using a novel realistic Hamiltonian derived from chiral perturbation theory including three-body potential contributions and are confronted with the experimental findings. The new results show maximum E2 strength in comparison with known values along the N=28 chain of isotones. The results corroborate the high collectivity for the double shell closure at N=Z=28 which was anticipated from the large B(E2;21+→0g.s.+) value despite the considerable increase of its excitation energy as compared to neighboring semi-magic nuclei. Based on similarities in the shell structures of the self-conjugate doubly-magic nuclei 56Ni and 100Sn, the new values could be an indication for an expected comparable collective behavior of the 61+ state in 100Sn.
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