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- Shimwell, T. W., et al.
(author)
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The LOFAR Two-metre Sky Survey: V. Second data release
- 2022
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In: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 659
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Journal article (peer-reviewed)abstract
- In this data release from the ongoing LOw-Frequency ARray (LOFAR) Two-metre Sky Survey we present 120a 168 MHz images covering 27% of the northern sky. Our coverage is split into two regions centred at approximately 12h45m +44 30a and 1h00m +28 00a and spanning 4178 and 1457 square degrees respectively. The images were derived from 3451 h (7.6 PB) of LOFAR High Band Antenna data which were corrected for the direction-independent instrumental properties as well as direction-dependent ionospheric distortions during extensive, but fully automated, data processing. A catalogue of 4 396 228 radio sources is derived from our total intensity (Stokes I) maps, where the majority of these have never been detected at radio wavelengths before. At 6a resolution, our full bandwidth Stokes I continuum maps with a central frequency of 144 MHz have: a median rms sensitivity of 83 μJy beama 1; a flux density scale accuracy of approximately 10%; an astrometric accuracy of 0.2a; and we estimate the point-source completeness to be 90% at a peak brightness of 0.8 mJy beama 1. By creating three 16 MHz bandwidth images across the band we are able to measure the in-band spectral index of many sources, albeit with an error on the derived spectral index of > a ±a 0.2 which is a consequence of our flux-density scale accuracy and small fractional bandwidth. Our circular polarisation (Stokes V) 20a resolution 120a168 MHz continuum images have a median rms sensitivity of 95 μJy beama 1, and we estimate a Stokes I to Stokes V leakage of 0.056%. Our linear polarisation (Stokes Q and Stokes U) image cubes consist of 480a A a 97.6 kHz wide planes and have a median rms sensitivity per plane of 10.8 mJy beama 1 at 4a and 2.2 mJy beama 1 at 20a; we estimate the Stokes I to Stokes Q/U leakage to be approximately 0.2%. Here we characterise and publicly release our Stokes I, Q, U and V images in addition to the calibrated uv-data to facilitate the thorough scientific exploitation of this unique dataset.
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- Valiente-Dobón, J.J., et al.
(author)
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Manifestation of the Berry phase in the atomic nucleus 213Pb
- 2021
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In: Physics Letters B. - : Elsevier BV. - 0370-2693. ; 816
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Journal article (peer-reviewed)abstract
- The neutron-rich 213Pb isotope was produced in the fragmentation of a primary 1 GeV A 238U beam, separated in FRS in mass and atomic number, and then implanted for isomer decay γ-ray spectroscopy with the RISING setup at GSI. A newly observed isomer and its measured decay properties indicate that states in 213Pb are characterized by the seniority quantum number that counts the nucleons not in pairs coupled to angular momentum J=0. The conservation of seniority is a consequence of a geometric phase associated with particle-hole conjugation, which becomes observable in semi-magic nuclei where nucleons half-fill the valence shell. The γ-ray spectroscopic observables in 213Pb are thus found to be driven by two mechanisms, particle-hole conjugation and seniority conservation, which are intertwined through a Berry phase.
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- Zago, L., et al.
(author)
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High-spin states in 212Po above the α-decaying (18+) isomer
- 2022
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In: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 834
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Journal article (peer-reviewed)abstract
- The nucleus 212Po has been produced through the fragmentation of a 238U primary beam at 1 GeV/nucleon at GSI, separated with the FRagment Separator, FRS, and studied via isomer γ-decay spectroscopy with the RISING setup. Two delayed previously unknown γ rays have been observed. One has been attributed to the E3 decay of a 21− isomeric state feeding the α-emitting 45-s (18+) high-spin isomer. The other γ-ray line has been assigned to the decay of a higher-lying 23+ metastable state. These are the first observations of high-spin states above the 212Po (18+) isomer, by virtue of the selectivity obtained via ion-by-ion identification of 238U fragmentation products. Comparison with shell-model calculations points to shortfalls in the nuclear interactions involving high-j proton and neutron orbitals, to which the region around Z∼100 is sensitive.
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| 5. |
- Das, P., et al.
(author)
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Study of exotic decay of Cs isotope close to the proton drip line
- 2020
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In: 27th International Nuclear Physics Conference (INPC2019) 29 July - 2 August 2019, Glasgow, UK. - : IOP Publishing. - 1742-6588. ; 1643
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Conference paper (peer-reviewed)abstract
- The neutron-deficient 115Cs was produced at ISOLDE, CERN by spallation reaction using 1.4 GeV proton on LaC2 target. The exotic decay modes were studied by using a charged particle array (DSSD and pad detectors) and a γ-detector array (four Clovers) at the ISOLDE decay station (IDS). In this report, results on observed β-delayed particle emission from 115Cs, a nucleus close to proton drip line, is presented. By measuring the time distribution in the delayed proton spectrum, the half-life of the ground state of 115Cs was extracted. The obtained half-life is in agreement with previous reported value. For the first time, the p-unbound states of 115Xe, obtained by measuring beta-delayed protons from 115Cs is reported.
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| 6. |
- Das, P., et al.
(author)
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Exotic decay of 115Cs
- 2023
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In: Physical Review C. - 2469-9985. ; 108:6
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Journal article (peer-reviewed)abstract
- The detailed study of the β+/EC decay of the very neutron-deficient and alpha-unbound nucleus 115Cs is presented. The measurement was performed at the ISOLDE, CERN where delayed charged particles and γ rays were detected. The observed delayed γ rays are in agreement with the previously reported characteristics γ rays of 115Xe. Based on the experimental observations, the tentative ground-state spin of 115Cs is suggested to be 7/2+ or 9/2+. Furthermore, the measured decay branching ratio of delayed protons exceeds the previously reported value. Additionally, new delayed α-branching ratio and several reconstructed proton and α-unbound excited states of 115Xe are being reported for the first time. The properties of proton-unbound states at excitation energies from 3.9–7.9 MeV have been obtained by fitting the delayed proton spectrum via the Bayesian method. The measured lifetimes of these proton-unbound states are in the order of zeptoseconds.
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| 8. |
- Karl, J. A., et al.
(author)
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The Cross-cultural Validity of the Five-Facet Mindfulness Questionnaire Across 16 Countries
- 2020
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In: Mindfulness. - : Springer Science and Business Media LLC. - 1868-8527 .- 1868-8535. ; 11, s. 1226-1237
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Journal article (peer-reviewed)abstract
- Objectives The goal of the current study was to investigate the universality of the five-factor model of mindfulness and the measurement equivalence of the Five-Facet Mindfulness Questionnaire (FFMQ). Methods The study used FFMQ data from published and unpublished research conducted in 16 countries (total N = 8541). Using CFA, different models, proposed in the literature, were fitted. To test the cross-cultural equivalence of the best fitting model, a multi-group confirmatory factor analysis was used. Further, the equivalence of individual facets of the FFMQ and potential sources of non-equivalence was explored. Results The best fitting models in most samples were a five-facet model with a higher-order mindfulness factor and uncorrelated positive and negative item-wording factors and a five-facet model with a correlated facets and uncorrelated positive and negative item-wording factors. These models showed structural equivalence, but did not show metric equivalence (equivalent factor loadings) across cultures. Given this lack of equivalent factor loadings, not even correlations or mean patterns can be compared across cultures. A similar pattern was observed when testing the equivalence of the individual facets; all individual facets failed even tests of metric equivalence. A sample size weighted exploratory factor analysis across cultures indicated that a six-factor solution might provide the best fit across cultures with acting with awareness split into two factors. Finally, both the five- and six-factor solution showed substantially better fit in more individualistic and less tight cultures. Conclusions Overall, the FFMQ has conceptual and measurement problems in a cross-cultural context, raising questions about the validity of the current conceptualization of mindfulness across cultures. The results showed that the fit of the FFMQ was substantially better in individualistic cultures that indicate that further data from non-Western cultures is needed to develop a universal conceptualization and measurement of mindfulness.
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