| 1. |
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| 2. |
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| 3. |
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| 4. |
- Reifarth, R., et al.
(författare)
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Nuclear astrophysics with radioactive ions at FAIR
- 2016
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Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 665:1
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Konferensbidrag (refereegranskat)abstract
- The nucleosynthesis of elements beyond iron is dominated by neutron captures in the s and r processes. However, 32 stable, proton-rich isotopes cannot be formed during those processes, because they are shielded from the s-process flow and r-process beta-decay chains. These nuclei are attributed to the p and rp process. For all those processes, current research in nuclear astrophysics addresses the need for more precise reaction data involving radioactive isotopes. Depending on the particular reaction, direct or inverse kinematics, forward or time-reversed direction are investigated to determine or at least to constrain the desired reaction cross sections. The Facility for Antiproton and Ion Research (FAIR) will offer unique, unprecedented opportunities to investigate many of the important reactions. The high yield of radioactive isotopes, even far away from the valley of stability, allows the investigation of isotopes involved in processes as exotic as the r or rp processes.
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| 5. |
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| 6. |
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| 7. |
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| 8. |
- Khuyagbaatar, J., et al.
(författare)
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48Ca+249Bk Fusion Reaction Leading to Element Z=117: Long-Lived α-Decaying 270Db and Discovery of 266Lr
- 2014
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Ingår i: Physical Review Letters. - 1079-7114. ; 112:17
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Tidskriftsartikel (refereegranskat)abstract
- The superheavy element with atomic number Z=117 was produced as an evaporation residue in the 48Ca+249Bk fusion reaction at the gas-filled recoil separator TASCA at GSI Darmstadt, Germany. The radioactive decay of evaporation residues and their α-decay products was studied using a detection setup that allowed measuring decays of single atomic nuclei with half-lives between sub-μs and a few days. Two decay chains comprising seven α decays and a spontaneous fission each were identified and are assigned to the isotope 294-117 and its decay products. A hitherto unknown α-decay branch in 270Db (Z=105) was observed, which populated the new isotope 266Lr (Z=103). The identification of the long-lived (T1/2=1.0+1.9−0.4 h) α-emitter 270Db marks an important step towards the observation of even more long-lived nuclei of superheavy elements located on an “island of stability.”
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| 9. |
- Khuyagbaatar, J., et al.
(författare)
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Fusion reaction 48Ca + 249Bk leading to formation of the element Ts (Z=117)
- 2019
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Ingår i: Physical Review C. - 2469-9985. ; 99:5
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Tidskriftsartikel (refereegranskat)abstract
- The heaviest currently known nuclei, which have up to 118 protons, have been produced in 48Ca induced reactions with actinide targets. Among them, the element tennessine (Ts), which has 117 protons, has been synthesized by fusing 48Ca with the radioactive target 249Bk, which has a half-life of 327 d. The experiment was performed at the gas-filled recoil separator TASCA. Two long and two short α decay chains were observed. The long chains were attributed to the decay of 294Ts. The possible origin of the short-decay chains is discussed in comparison with the known experimental data. They are found to fit with the decay chain patterns attributed to 293Ts. The present experimental results confirm the previous findings at the Dubna Gas-Filled Recoil Separator on the decay chains originating from the nuclei assigned to Ts.
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| 10. |
- Khuyagbaatar, J., et al.
(författare)
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Search for elements 119 and 120
- 2020
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Ingår i: Physical Review C. - 2469-9985. ; 102:6
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Tidskriftsartikel (refereegranskat)abstract
- A search for production of the superheavy elements with atomic numbers 119 and 120 was performed in the 50Ti+249Bk and 50Ti+249Cf fusion-evaporation reactions, respectively, at the gas-filled recoil separator TASCA at GSI Darmstadt, Germany. Over four months of irradiation, the 249Bk target partially decayed into 249Cf, which allowed for a simultaneous search for both elements. Neither was detected at cross-section sensitivity levels of 65 and 200 fb for the 50Ti+249Bk and 50Ti+249Cf reactions, respectively, at a midtarget beam energy of Elab = 281.5 MeV. The nonobservation of elements 119 and 120 is discussed within the concept of fusion-evaporation reactions including various theoretical predictions on the fission-barrier heights of superheavy nuclei in the region of the island of stability.
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| 11. |
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| 12. |
- Cox, D. M., et al.
(författare)
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Spectroscopy along flerovium decay chains. II. Fine structure in odd-A 289Fl
- 2023
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Ingår i: Physical Review C. - 2469-9985. ; 107:2
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Tidskriftsartikel (refereegranskat)abstract
- Fifteen correlated α-decay chains starting from the odd-A superheavy nucleus 289Fl were observed following the fusion-evaporation reaction 48Ca+244Pu. The results call for at least two parallel α-decay sequences starting from at least two different states of 289Fl. This implies that close-lying levels in nuclei along these chains have quite different spin-parity assignments. Further, observed α-electron and α-photon coincidences, as well as the α-decay fine structure along the decay chains, suggest a change in the ground-state spin assignment between 285Cn and 281Ds. Our experimental results, on the excited level structure of the heaviest odd-N nuclei to date, provide a direct testing ground for theory. This is illustrated by comparison with new nuclear structure calculations based on the symmetry-conserving configuration mixing theory.
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| 13. |
- Såmark-Roth, A., et al.
(författare)
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Spectroscopy along flerovium decay chains. III. Details on experiment, analysis, 282Cn, and spontaneous fission branches
- 2023
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Ingår i: Physical Review C. - 2469-9985. ; 107:2
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Tidskriftsartikel (refereegranskat)abstract
- Flerovium isotopes (element Z = 114) were produced in the fusion-evaporation reactions 48Ca+242,244Pu and studied with an upgraded TASISpec decay station placed in the focal plane of the gas-filled separator TASCA at the GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt, Germany. Twenty-nine flerovium decay chains were identified by means of correlated implantation, α decay, and spontaneous fission events. Data analysis aspects and statistical assessments, primarily based on measured rates of various events, which laid the foundation for the comprehensive spectroscopic information on the flerovium decay chains, are presented in detail. Various decay scenarios of an excited state observed in 282Cn are examined in depth with the help of GEANT4 simulations and assessed by predictions of beyond mean-field calculations including triaxial shape degrees of freedom. Previous, revised, and newly derived fission probabilities of even-even superheavy nuclei are compared with various theoretical predictions.
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| 14. |
- Di Nitto, A., et al.
(författare)
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Study of Non-fusion Products in the 50Ti+249Cf Reaction
- 2018
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Ingår i: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 784, s. 199-205
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Tidskriftsartikel (refereegranskat)abstract
- The isotopic distribution of nuclei produced in the 50Ti + 249Cf reaction has been studied at the gas-filled recoil separator TASCA at GSI Darmstadt, which separates ions according to differences in magnetic rigidity. The bombardment was performed at an energy around the Bass barrier and with the TASCA magnetic fields set for collecting fusion-evaporation reaction products. Fifty-three isotopes located “north-east” of 208Pb were identified as recoiling products formed in non-fusion channels of the reaction. These recoils were implanted with energies in two distinct ranges; besides one with higher energy, a significant low-energy contribution was identified. The latter observation was not expected to occur according to kinematics of the known types of reactions, namely quasi-elastic, multi-nucleon transfer, deep-inelastic collisions or quasifission. The present observations are discussed within the framework of two-body kinematics passing through the formation of a composite system.
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| 15. |
- Forsberg, Ulrika, et al.
(författare)
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Spectroscopic Tools Applied to Element Z = 115 Decay Chains
- 2014
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Ingår i: EPJ Web of Conferences. - : EDP Sciences. - 2100-014X .- 2101-6275. - 9782759811755 - 9782759811762 ; 66, s. 02036-02036
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Konferensbidrag (refereegranskat)abstract
- Nuclides that are considered to be isotopes of element Z = 115 were produced in the reaction 48Ca + 243Am at the GSI Helmholtzzentrum für Schwerionenforschung Darmstadt. The detector setup TASISpec was used. It was mounted behind the gas-filled separator TASCA. Thirty correlated α-decay chains were found, and the energies of the particles were determined with high precision. Two important spectroscopic aspects of the offline data analysis are discussed in detail: the handling of digitized preamplified signals from the silicon strip detectors, and the energy reconstruction of particles escaping to upstream detectors relying on pixel-by-pixel dead-layer thicknesses.
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| 16. |
- Gehlen, J., et al.
(författare)
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First genome-wide association study of esophageal atresia identifies three genetic risk loci at CTNNA3, FOXF1/FOXC2/FOXL1, and HNF1B
- 2022
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Ingår i: Human Genetics and Genomics Advances. - : Elsevier BV. - 2666-2477. ; 3:2
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Tidskriftsartikel (refereegranskat)abstract
- Esophageal atresia with or without tracheoesophageal fistula (EA/TEF) is the most common congenital malformation of the upper digestive tract. This study represents the first genome-wide association study (GWAS) to identify risk loci for EA/TEF. We used a European case-control sample comprising 764 EA/TEF patients and 5,778 controls and observed genome-wide significant associations at three loci. On chromosome 10q21 within the gene CTNNA3 (p = 2.11 × 10−8; odds ratio [OR] = 3.94; 95% confidence interval [CI], 3.10–5.00), on chromosome 16q24 next to the FOX gene cluster (p = 2.25 × 10−10; OR = 1.47; 95% CI, 1.38–1.55) and on chromosome 17q12 next to the gene HNF1B (p = 3.35 × 10−16; OR = 1.75; 95% CI, 1.64–1.87). We next carried out an esophageal/tracheal transcriptome profiling in rat embryos at four selected embryonic time points. Based on these data and on already published data, the implicated genes at all three GWAS loci are promising candidates for EA/TEF development. We also analyzed the genetic EA/TEF architecture beyond the single marker level, which revealed an estimated single-nucleotide polymorphism (SNP)-based heritability of around 37% ± 14% standard deviation. In addition, we examined the polygenicity of EA/TEF and found that EA/TEF is less polygenic than other complex genetic diseases. In conclusion, the results of our study contribute to a better understanding on the underlying genetic architecture of ET/TEF with the identification of three risk loci and candidate genes. © 2022 The Authors
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| 17. |
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| 18. |
- Antonov, A. N., et al.
(författare)
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The electron-ion scattering experiment ELISe at the International Facility for Antiproton and Ion Research (FAIR)-A conceptual design study
- 2011
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Ingår i: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. - : Elsevier BV. - 0168-9002 .- 0167-5087. ; 637:1, s. 60-76
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Tidskriftsartikel (refereegranskat)abstract
- The electron-ion scattering experiment ELISe is part of the installations envisaged at the new experimental storage ring at the International Facility for Antiproton and Ion Research (FAIR) in Darmstadt, Germany. It offers an unique opportunity to use electrons as probe in investigations of the structure of exotic nuclei. The conceptual design and the scientific challenges of ELISe are presented. (C) 2011 Elsevier B.V. All rights reserved.
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| 19. |
- Forsberg, U., et al.
(författare)
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Recoil-α-fission and recoil-α-α-fission events observed in the reaction 48Ca + 243Am
- 2016
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Ingår i: Nuclear Physics, Section A. - : Elsevier BV. - 0375-9474. ; 953, s. 117-138
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Tidskriftsartikel (refereegranskat)abstract
- Products of the fusion-evaporation reaction 48Ca + 243Am were studied with the TASISpec set-up at the gas-filled separator TASCA at the GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany. Amongst the detected thirty correlated α-decay chains associated with the production of element Z=115, two recoil-α-fission and five recoil-α-α-fission events were observed. The latter five chains are similar to four such events reported from experiments performed at the Dubna gas-filled separator, and three such events reported from an experiment at the Berkeley gas-filled separator. The four chains observed at the Dubna gas-filled separator were assigned to start from the 2n-evaporation channel 289115 due to the fact that these recoil-α-α-fission events were observed only at low excitation energies. Contrary to this interpretation, we suggest that some of these recoil-α-α-fission decay chains, as well as some of the recoil-α-α-fission and recoil-α-fission decay chains reported from Berkeley and in this article, start from the 3n-evaporation channel 288115.
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| 20. |
- Såmark-Roth, A., et al.
(författare)
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Low-lying states in 219Ra and 215Rn : Sampling microsecond α-decaying nuclei
- 2018
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Ingår i: Physical Review C. - 2469-9985. ; 98:4
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Tidskriftsartikel (refereegranskat)abstract
- Short-lived α-decaying nuclei "northeast" of 208Pb in the chart of nuclides were studied using the reaction 48Ca+243Am with the decay station TASISpec at TASCA, GSI Darmstadt. Decay energies and times from pile-up events were extracted with a tailor-made pulse-shape analysis routine and specific α-decay chains were identified in a correlation analysis. Decay chains starting with the even-even 220Ra and its odd-A neighbors, 219Fr, and 219,221Ra, with a focus on the 219Ra→215Rn decay, were studied by means of α-γ spectroscopy. A revised α-decay scheme of 219Ra is proposed, including a new decay branch from a previously not considered isomeric state at 17 keV excitation energy. Conclusions on nuclear structure are drawn from the experimental data, aided by Geant4 simulations and a discussion on theoretical calculations.
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| 21. |
- Såmark-Roth, Anton, et al.
(författare)
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Spectroscopy along flerovium decay chains: Discovery of 280Ds and an excited state in 282Cn
- 2021
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Ingår i: Physical Review Letters. - 1079-7114. ; 126:3
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Tidskriftsartikel (refereegranskat)abstract
- A nuclear spectroscopy experiment was conducted to study α-decay chains stemming from isotopes of flerovium (element Z=114). An upgraded TASISpec decay station was placed behind the gas-filled separator TASCA at the GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt, Germany. The fusion-evaporation reactions 48Ca+242Pu and 48Ca+244Pu provided a total of 32 flerovium-candidate decay chains, of which two and eleven were firmly assigned to 286Fl and 288Fl, respectively. A prompt coincidence between a 9.60(1)-MeV α-particle event and a 0.36(1)-MeV conversion electron marked the first observation of an excited state in an even-even isotope of the heaviest man-made elements, namely 282Cn. Spectroscopy of 288Fl decay chains fixed Qα=10.06(1) MeV. In one case, a Qα=9.46(1)-MeV decay from 284Cn into 280Ds was observed, with 280Ds fissioning after only 518 μs. The impact of these findings, aggregated with existing data on decay chains of 286,288Fl, on the size of an anticipated shell gap at proton number Z=114 is discussed in light of predictions from two beyond-mean-field calculations, which take into account triaxial deformation.
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| 22. |
- Yakushev, A., et al.
(författare)
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On the adsorption and reactivity of element 114, flerovium
- 2022
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Ingår i: Frontiers in Chemistry. - : Frontiers Media SA. - 2296-2646. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Flerovium (Fl, element 114) is the heaviest element chemically studied so far. To date, its interaction with gold was investigated in two gas-solid chromatography experiments, which reported two different types of interaction, however, each based on the level of a few registered atoms only. Whereas noble-gas-like properties were suggested from the first experiment, the second one pointed at a volatile-metal-like character. Here, we present further experimental data on adsorption studies of Fl on silicon oxide and gold surfaces, accounting for the inhomogeneous nature of the surface, as it was used in the experiment and analyzed as part of the reported studies. We confirm that Fl is highly volatile and the least reactive member of group 14. Our experimental observations suggest that Fl exhibits lower reactivity towards Au than the volatile metal Hg, but higher reactivity than the noble gas Rn.
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| 23. |
- Cox, D. M., et al.
(författare)
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Spectroscopic Tools Applied to Flerovium Decay Chains
- 2020
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Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 1643
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Tidskriftsartikel (refereegranskat)abstract
- An upgraded TASISpec setup, with the addition of a veto DSSD and the new Compex detector-germanium array, has been employed with the gas-filled recoil separator TASCA at the GSI Helmholtzzentrum für Schwerionenforschung Darmstadt, to study flerovium (element 114) decay chains. The detector upgrades along with development of new analytical techniques have improved the sensitivity of the TASISpec setup for measuring α-photon coincidences. These improvements have been assessed with test reactions. The reaction 48Ca+206,207Pb was used for verification of experimental parameters such as transmission to implantation DSSD and target-segment to α-decay correlations. The reaction 48Ca+ natHf was used to produce several short-lived nuclei with multiple-α decay chains to investigate pile-up event deconvolution.
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| 24. |
- Pawlowski, P., et al.
(författare)
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Neutron recognition in the LAND detector for large neutron multiplicity
- 2012
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Ingår i: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. - : Elsevier BV. - 0168-9002. ; 694, s. 47-54
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Tidskriftsartikel (refereegranskat)abstract
- The performance of the LAND neutron detector is studied. Using an event-mixing technique based on one-neutron data obtained in the S107 experiment at the GSI laboratory, we test the efficiency of various analytic tools used to determine the multiplicity and kinematic properties of detected neutrons. A new algorithm developed recently for recognizing neutron showers from spectator decays in the ALADIN experiment S254 is described in detail. Its performance is assessed in comparison with other methods. The properties of the observed neutron events are used to estimate the detection efficiency of LAND in this experiment. (C) 2012 Elsevier B.V. All rights reserved.
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| 25. |
- Rudolph, Dirk, et al.
(författare)
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Alpha-Photon Coincidence Spectroscopy Along Element 115 Decay Chains
- 2014
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Ingår i: Acta Physica Polonica. Series B: Elementary Particle Physics, Nuclear Physics, Statistical Physics, Theory of Relativity, Field Theory. - 0587-4254. ; 45, s. 263-272
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Tidskriftsartikel (refereegranskat)abstract
- Produced in the reaction 48Ca+243Am, thirty correlated α-decay chains were observed in an experiment conducted at the GSI Helmholzzentrum für Schwerionenforschung, Darmstadt, Germany. The decay chains are basically consistent with previous findings and are considered to originate from isotopes of element 115 with mass numbers 287, 288, and 289. A set-up aiming specifically for high-resolution charged particle and photon coincidence spectroscopy was placed behind the gas-filled separator TASCA. For the first time, γ rays as well as X-ray candidates were observed in prompt coincidence with the α-decay chains of element 115.
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| 26. |
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| 27. |
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| 28. |
- Rudolph, Dirk, et al.
(författare)
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Selected Spectroscopic Results on Element 115 Decay Chains
- 2015
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Ingår i: Journal of Radioanalytical and Nuclear Chemistry. - : Springer Science and Business Media LLC. - 0236-5731 .- 1588-2780. ; 303:2, s. 1185-1190
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Tidskriftsartikel (refereegranskat)abstract
- Thirty correlated alpha-decay chains were observed in an experiment studying the fusion-evaporation reaction 48Ca + 243Am at the GSI Helmholtzzentrum f¨ur Schwerionenforschung. The decay characteristics of the majority of these 30 chains are consistent with previous observations and interpretations of such chains to originate from isotopes of element Z = 115. High-resolution alpha-photon coincidence spectroscopy in conjunction with comprehensive Monte-Carlo simulations allow to propose excitation schemes of atomic nuclei of the heaviest elements, thereby probing nuclear structure models near the ‘Island of Stability’ with unprecedented experimental precision.
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| 29. |
- Rudolph, Dirk, et al.
(författare)
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Spectroscopy of Element 115 Decay Chains
- 2013
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Ingår i: Physical Review Letters. - 1079-7114. ; 111:11
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Tidskriftsartikel (refereegranskat)abstract
- A high-resolution , X-ray and gamma-ray coincidence spectroscopy experiment was conducted at the GSI Helmholtzzentrum für Schwerionenforschung. Thirty correlated alpha-decay chains were detected following the fusion-evaporation reaction 48Ca + 243Am. The observations are consistent with previous assignments of similar decay chains to originate from element Z = 115. For the first time, precise spectroscopy allows the derivation of excitation schemes of isotopes along the decay chains starting with elements Z > 112. Comprehensive Monte-Carlo simulations accompany the data analysis. Nuclear structure models provide a first level interpretation.
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| 30. |
- Lukasik, J., et al.
(författare)
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Discriminant analysis and secondary-beam charge recognition
- 2008
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Ingår i: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. - : Elsevier BV. - 0168-9002. ; 587:2-3, s. 413-419
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Tidskriftsartikel (refereegranskat)abstract
- The discriminant-analysis method has been applied to optimize the exotic-beam charge recognition in a projectile fragmentation experiment. The experiment was carried out at the GSI using the fragment separator (FRS) to produce and select the relativistic secondary beams, and the ALADIN setup to measure their fragmentation products following collisions with Sn target nuclei. The beams of neutron poor isotopes around La-124 and Sn-107 were selected to study the isospin dependence of the limiting temperature of heavy nuclei by comparing with results for stable Sn-124 projectiles. A dedicated detector to measure the projectile charge upstream of the reaction target was not used, and alternative methods had to be developed. The presented method, based on the multivariate discriminant analysis, allowed to increase the efficacy of charge recognition up to about 90%, which was about 20% more than achieved with the simple scalar methods.
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| 31. |
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| 32. |
- Trautmann, W., et al.
(författare)
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Isotopic dependence of the caloric curve
- 2009
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Ingår i: Progress in Particle and Nuclear Physics. - : Elsevier BV. - 0146-6410. ; 62:2, s. 407-412
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Tidskriftsartikel (refereegranskat)abstract
- Isotopic effects in projectile fragmentation at relativistic energies have been studied with the ALADIN forward spectrometer at SIS. Stable and radioactive Sn and La beams with an incident energy of 600 MeV per nucleon have been used in order to explore a wide range of isotopic compositions. Chemical freeze-out temperatures are found to be nearly invariant with respect to the A/Z ratio of the produced spectator sources, consistent with predictions for expanded systems. Consequences for the proposed interpretation of chemical breakup temperatures as representing the limiting temperatures predicted by microscopic models are discussed. (C) 2009 Elsevier B.V. All rights reserved.
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| 33. |
- Pellissier, V., et al.
(författare)
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Effects of Natura 2000 on nontarget bird and butterfly species based on citizen science data
- 2020
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Ingår i: Conservation Biology. - : Wiley. - 0888-8892 .- 1523-1739. ; 34:3, s. 666-676
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Tidskriftsartikel (refereegranskat)abstract
- The European Union's Natura 2000 (N2000) is among the largest international networks of protected areas. One of its aims is to secure the status of a predetermined set of (targeted) bird and butterfly species. However, nontarget species may also benefit from N2000. We evaluated how the terrestrial component of this network affects the abundance of nontargeted, more common bird and butterfly species based on data from long-term volunteer-based monitoring programs in 9602 sites for birds and 2001 sites for butterflies. In almost half of the 155 bird species assessed, and particularly among woodland specialists, abundance increased (slope estimates ranged from 0.101 [SD 0.042] to 3.51 [SD 1.30]) as the proportion of landscape covered by N2000 sites increased. This positive relationship existed for 27 of the 104 butterfly species (estimates ranged from 0.382 [SD 0.163] to 4.28 [SD 0.768]), although most butterflies were generalists. For most species, when land-cover covariates were accounted for these positive relationships were not evident, meaning land cover may be a determinant of positive effects of the N2000 network. The increase in abundance as N2000 coverage increased correlated with the specialization index for birds, but not for butterflies. Although the N2000 network supports high abundance of a large spectrum of species, the low number of specialist butterflies with a positive association with the N2000 network shows the need to improve the habitat quality of N2000 sites that could harbor open-land butterfly specialists. For a better understanding of the processes involved, we advocate for standardized collection of data at N2000 sites.
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| 34. |
- Yakushev, A., et al.
(författare)
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First Study on Nihonium (Nh, Element 113) Chemistry at TASCA
- 2021
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Ingår i: Frontiers in Chemistry. - : Frontiers Media SA. - 2296-2646. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Nihonium (Nh, element 113) and flerovium (Fl, element 114) are the first superheavy elements in which the 7p shell is occupied. High volatility and inertness were predicted for Fl due to the strong relativistic stabilization of the closed 7p1/2 sub-shell, which originates from a large spin-orbit splitting between the 7p1/2 and 7p3/2 orbitals. One unpaired electron in the outermost 7p1/2 sub-shell in Nh is expected to give rise to a higher chemical reactivity. Theoretical predictions of Nh reactivity are discussed, along with results of the first experimental attempts to study Nh chemistry in the gas phase. The experimental observations verify a higher chemical reactivity of Nh atoms compared to its neighbor Fl and call for the development of advanced setups. First tests of a newly developed detection device miniCOMPACT with highly reactive Fr isotopes assure that effective chemical studies of Nh are within reach.
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| 35. |
- Le Gentil, E., et al.
(författare)
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Coincidence measurement of residues and light particles in the reaction Fe-56+p at 1 GeV per nucleon with the spallation reactions setup SPALADIN
- 2008
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Ingår i: Physical Review Letters. - 1079-7114 .- 0031-9007. ; 100:2
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Tidskriftsartikel (refereegranskat)abstract
- The spallation of Fe-56 in collisions with hydrogen at 1A GeV has been studied in inverse kinematics with the large-aperture setup SPALADIN at GSI. Coincidences of residues with low-center-of-mass kinetic energy light particles and fragments have been measured allowing the decomposition of the total reaction cross section into the different possible deexcitation channels. Detailed information on the evolution of these deexcitation channels with excitation energy has also been obtained. The comparison of the data with predictions of several deexcitation models coupled to the INCL4 intranuclear cascade model shows that only GEMINI can reasonably account for the bulk of collected results, indicating that in a light system with no compression and little angular momentum, multifragmentation might not be necessary to explain the data.
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| 36. |
- Morrison, C. A., et al.
(författare)
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Bird population declines and species turnover are changing the acoustic properties of spring soundscapes
- 2021
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Natural sounds, and bird song in particular, play a key role in building and maintaining our connection with nature, but widespread declines in bird populations mean that the acoustic properties of natural soundscapes may be changing. Using data-driven reconstructions of soundscapes in lieu of historical recordings, here we quantify changes in soundscape characteristics at more than 200,000 sites across North America and Europe. We integrate citizen science bird monitoring data with recordings of individual species to reveal a pervasive loss of acoustic diversity and intensity of soundscapes across both continents over the past 25 years, driven by changes in species richness and abundance. These results suggest that one of the fundamental pathways through which humans engage with nature is in chronic decline, with potentially widespread implications for human health and well-being.
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| 37. |
- Pawłowski, P., et al.
(författare)
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Neutrons from projectile fragmentation at 600 MeV/nucleon
- 2023
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Ingår i: Physical Review C. - 2469-9993 .- 2469-9985. ; 108:4
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Tidskriftsartikel (refereegranskat)abstract
- The neutron emission in projectile fragmentation at relativistic energies was studied with the Large-Area-Neutron-Detector LAND coupled to the ALADIN forward spectrometer at the GSI Schwerionen-Synchrotron (SIS). Stable Sn124 and radioactive Sn107 and La124 beams with an incident energy of 600 MeV/nucleon were used to explore the N/Z dependence of the identified neutron source. A cluster-recognition algorithm is applied for identifying individual particles within the hit distributions registered with LAND. The obtained momentum distributions are extrapolated over the full phase space occupied by the neutrons from the projectile-spectator source. The mean multiplicities of spectator neutrons reach values of up to about 11 and depend strongly on the isotopic composition of the projectile. An effective source temperature of T≈2-5 MeV, monotonically increasing with decreasing impact parameter, is deduced from the transverse momentum distributions. For the interpretation of the data, calculations with the statistical multifragmentation model were performed. The variety of excited projectile spectators assumed to decay statistically is represented by an ensemble of excited sources with parameters determined previously from the fragment production observed in the same experiments. The obtained agreement is very satisfactory for more peripheral collisions where, according to the model, neutrons are mainly emitted during the secondary decays of excited fragments. The neutron multiplicity in more central collisions is underestimated, indicating that other sources besides the modeled statistical breakup contribute to the observed neutron yield. The choice made for the symmetry-term coefficient of the liquid-drop description of produced fragments has a weak effect on the predicted neutron multiplicities.
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| 38. |
- Kessing, C. F., et al.
(författare)
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High Number of Activated CD8(+) T Cells Targeting HIV Antigens Are Present in Cerebrospinal Fluid in Acute HIV Infection
- 2017
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Ingår i: Jaids-Journal of Acquired Immune Deficiency Syndromes. - 1525-4135. ; 75:1, s. 108-117
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Tidskriftsartikel (refereegranskat)abstract
- Background: Central nervous system (CNS) infiltration by CD8(+) T cells is associated with neuroinflammation in many neurodegenerative diseases, including HIV-associated dementia. However, the role of CD8(+) T cells in the CNS during acute HIV infection (AHI) is unknown. Methods: We analyzed the phenotype, gene expression, T cell receptor (TCR) repertoire, and HIV specificity of CD8(+) T cells in cerebrospinal fluid (CSF) of a unique cohort captured during the earliest stages of AHI (n = 26), chronic (n = 23), and uninfected (n = 8). Results: CSF CD8(+) T cells were elevated in AHI compared with uninfected controls. The frequency of activated CSF CD8(+) T cells positively correlated to CSF HIV RNA and to markers of CNS inflammation. In contrast, activated CSF CD8(+) T cells during chronic HIV infection were associated with markers of neurological injury and microglial activation. CSF CD8(+) T cells in AHI exhibited increased functional gene expression profiles associated with CD8(+) T cells effector function, proliferation, and TCR signaling, a unique restricted TCR Vbeta repertoire and contained HIV-specific CD8(+) T cells directed to unique HIV epitopes compared with the periphery. Conclusions: These results suggest that CSF CD8(+) T cells in AHI expanding in the CNS are functional and directed against HIV antigens. These cells could thus play a beneficial role protective of injury seen in chronic HIV infection if combination antiretroviral therapy is initiated early.
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| 39. |
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| 40. |
- Nilsson, Thomas, 1965, et al.
(författare)
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He-6 and neutron momentum distributions from He-8 in nuclear break-up reactions at 240 MeV/u
- 1996
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Ingår i: Nuclear Physics A. - 0375-9474. ; 598:3, s. 418-434
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Tidskriftsartikel (refereegranskat)abstract
- Neutron and He-6 momentum distributions from He-8 break-up reactions in a C target have been measured at 240 MeV/u. The two-neutron removal cross section was found to be sigma(-2n) = 0.27 +/- 0.03 b. The nature of the momentum distributions is interpreted in some simple reaction scenarios.
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| 41. |
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| 42. |
- Humbert, F., et al.
(författare)
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Longitudinal and Transverse-Momentum Distributions of Li-9 Fragments from Break-up of Li-11
- 1995
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Ingår i: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - 0370-2693. ; 347:3-4, s. 198-204
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Tidskriftsartikel (refereegranskat)abstract
- Transverse and longitudinal momentum distributions of Li-9 fragments from Li-11 break-up reactions in C, Al and Pb targets have been measured at 280 MeV/u. The two-neutron removal cross-section was measured to be sigma(-2n), = 0.26 +/- 0.02 b for the carbon target, sigma(-2n) = 0.47 +/- 0.08 b for the aluminum target and sigma(-2n), = 1.9 +/- 0.4 b for the lead target. No significant difference is observed between the narrow widths (FWHM approximate to 47 MeV/c) of the transverse and longitudinal momentum distributions of the Li-9 fragments. The physical implications of this are discussed.
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| 43. |
- Kasai, Y., et al.
(författare)
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Validation of stratospheric and mesospheric ozone observed by SMILES from International Space Station
- 2013
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Ingår i: Atmospheric Measurement Techniques. - : Copernicus GmbH. - 1867-1381 .- 1867-8548. ; 6:9, s. 2311-2338
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Tidskriftsartikel (refereegranskat)abstract
- We observed ozone (O3) in the vertical region between 250 and 0.0005 hPa (~ 12–96 km) using the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) on the Japanese Experiment Module (JEM) of the International Space Station (ISS) between 12 October 2009 and 21 April 2010. The new 4 K superconducting heterodyne receiver technology of SMILES allowed us to obtain a one order of magnitude better signal-to-noise ratio for the O3 line observation compared to past spaceborne microwave instruments. The non-sun-synchronous orbit of the ISS allowed us to observe O3 at various local times. We assessed the quality of the vertical profiles of O3 in the 100–0.001 hPa (~ 16–90 km) region for the SMILES NICT Level 2 product version 2.1.5. The evaluation is based on four components: error analysis; internal comparisons of observations targeting three different instrumental setups for the same O3 625.371 GHz transition; internal comparisons of two different retrieval algorithms; and external comparisons for various local times with ozonesonde, satellite and balloon observations (ENVISAT/MIPAS, SCISAT/ACE-FTS, Odin/OSIRIS, Odin/SMR, Aura/MLS, TELIS). SMILES O3 data have an estimated absolute accuracy of better than 0.3 ppmv (3%) with a vertical resolution of 3–4 km over the 60 to 8 hPa range. The random error for a single measurement is better than the estimated systematic error, being less than 1, 2, and 7%, in the 40–1, 80–0.1, and 100–0.004 hPa pressure regions, respectively. SMILES O3 abundance was 10–20% lower than all other satellite measurements at 8–0.1 hPa due to an error arising from uncertainties of the tangent point information and the gain calibration for the intensity of the spectrum. SMILES O3 from observation frequency Band-B had better accuracy than that from Band-A. A two month period is required to accumulate measurements covering 24 h in local time of O3 profile. However such a dataset can also contain variation due to dynamical, seasonal, and latitudinal effects
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| 44. |
- Langrock, G., et al.
(författare)
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Digital liquid-scintillation counting and effective pulse-shape discrimination with artificial neural networks
- 2015
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Ingår i: Radiochimica Acta. - : Walter de Gruyter GmbH. - 0033-8230 .- 2193-3405. ; 103:1, s. 15-25
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Tidskriftsartikel (refereegranskat)abstract
- A typical problem in low-level liquid scintillation (LS) counting is the identification of alpha particles in the presence of a high background of beta and gamma particles. Especially the occurrence of beta-beta and beta-gamma pile-ups may prevent the unambiguous identification of an alpha signal by commonly used analog electronics. In this case, pulse-shape discrimination (PSD) and pile-up rejection (PUR) units show an insufficient performance. This problem was also observed in own earlier experiments on the chemical behaviour of transactinide elements using the liquid-liquid extraction system SISAK in combination with LS counting alpha-particle signals from the decay of the transactinides could not be unambiguously assigned. However, the availability of instruments for the digital recording of LS pulses changes the situation and provides possibilities for new approaches in the treatment of LS pulse shapes. In a SISAK experiment performed at PSI, Villigen, a fast transient recorder, a PC card with oscilloscope characteristics and a sampling rate of 1 giga samples s(-1) (1 ns per point), was used for the first time to record LS signals. It turned out, that the recorded signals were predominantly alpha, beta-beta and beta-gamma pile up, and fission events. This paper describes the subsequent development and use of artificial neural networks (ANN) based on the method of "back-propagation of errors" to automatically distinguish between different pulse shapes. Such networks can "learn" pulse shapes and classify hitherto unknown pulses correctly after a learning period. The results show that ANN in combination with fast digital recording of pulse shapes can be a powerful tool in LS spectrometry even at high background count rates.
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| 45. |
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| 46. |
- Mollenhauer, B., et al.
(författare)
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Monitoring of 30 marker candidates in early Parkinson disease as progression markers
- 2016
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Ingår i: Neurology. - 0028-3878. ; 87:2, s. 168-177
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Tidskriftsartikel (refereegranskat)abstract
- Objective: This was a longitudinal single-center cohort study to comprehensively explore multimodal progression markers for Parkinson disease (PD) in patients with recently diagnosed PD (n 123) and age-matched, neurologically healthy controls (HC; n 106). Methods: Thirty tests at baseline and after 24 months covered nonmotor symptoms (NMS), cognitive function, and REM sleep behavior disorder (RBD) by polysomnography (PSG), voxel-based morphometry (VBM) of the brain by MRI, and CSF markers. Linear mixed-effect models were used to estimate differences of rates of change and to provide standardized effect sizes (d) with 95% confidence intervals (CI). Results: A composite panel of 10 informative markers was identified. Significant relative worsening (PD vs HC) was seen with the following markers: the Unified Parkinson's Disease Rating Scale I (d 0.39; CI 0.09-0.70), the Autonomic Scale for Outcomes in Parkinson's Disease (d 0.25; CI 0.06-0.46), the Epworth Sleepiness Scale (d 0.47; CI 0.24-0.71), the RBD Screening Questionnaire (d 0.44; CI 0.25-0.64), and RBD by PSG (d 0.37; CI 0.19-0.55) as well as VBM units of cortical gray matter (d -0.2; CI -0.3 to -0.09) and hippocampus (d -0.15; CI -0.27 to -0.03). Markers with a relative improvement included the Nonmotor Symptom (Severity) Scale (d -0.19; CI -0.36 to -0.02) and 2 depression scales (Beck Depression Inventory d -0.18; CI -0.36 to 0; Montgomery-Åsberg Depression Rating Scale d -0.26; CI -0.47 to -0.04). Unexpectedly, cognitive measures and select laboratory markers were not significantly changed in PD vs HC participants. Conclusions: Current CSF biomarkers and cognitive scales do not represent useful progression markers. However, sleep and imaging measures, and to some extent NMS, assessed using adequate scales, may be more informative markers to quantify progression. © 2016 American Academy of Neurology.
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| 47. |
- Sievers, E., et al.
(författare)
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SRC inhibition represents a potential therapeutic strategy in liposarcoma
- 2015
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Ingår i: International Journal of Cancer. - : Wiley. - 0020-7136. ; 137:11, s. 2578-2588
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Tidskriftsartikel (refereegranskat)abstract
- Liposarcomas (LS) are the most common malignant mesenchymal tumors, with an overall long-term mortality rate of 60%. LS comprise three major subtypes, i.e., well-differentiated/dedifferentiated liposarcoma (WDLS/DDLS), myxoid/round cell liposarcoma (MLS) and pleomorphic liposarcoma (PLS). Aiming at the preclinical identification of novel therapeutic options, we here investigate the functional significance of SRC in primary human LS and in LS-derived cell lines. Immunohistochemical and Western blot analyses reveal relevant levels of activated p-(Tyr416)-SRC in LS of the different subtypes with particular activation in MLS and PLS. Dysregulation of the SRC modifiers CSK and PTP1B was excluded as major reason for the activation of the kinase. Consistent siRNA-mediated knockdown of SRC or inhibition by the SRC inhibitor Dasatinib led to decreased proliferation of LS cell lines of the different subtypes, with MLS cells reacting particularly sensitive in MTT assays. Flow cytometric analyses revealed that this effect was due to a significant decrease in mitotic activity and an induction of apoptosis. SRC inhibition by Dasatinib resulted in dephosphorylation of SRC itself, its interacting partners FAK and IGF-IR as well as its downstream target AKT. Consistent with a particular role of SRC in cell motility, Dasatinib reduced the migratory and invasive potential of MLS cells in Boyden chamber and Matrigel chamber assays. In summary, we provide evidence that SRC activation plays an important role in LS biology and therefore represents a potential therapeutic target, particularly in MLS and PLS.
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| 48. |
- Chen, Q., et al.
(författare)
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Biopolymer-Templated Deposition of Ordered and Polymorph Titanium Dioxide Thin Films for Improved Surface-Enhanced Raman Scattering Sensitivity
- 2022
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Ingår i: Advanced Functional Materials. - : Wiley. - 1616-301X .- 1616-3028. ; 32:6
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Tidskriftsartikel (refereegranskat)abstract
- Titanium dioxide (TiO2) is an excellent candidate material for semiconductor metal oxide-based substrates for surface-enhanced Raman scattering (SERS). Biotemplated fabrication of TiO2 thin films with a 3D network is a promising route for effectively transferring the morphology and ordering of the template into the TiO2 layer. The control over the crystallinity of TiO2 remains a challenge due to the low thermal stability of biopolymers. Here is reported a novel strategy of the cellulose nanofibril (CNF)-directed assembly of TiO2/CNF thin films with tailored morphology and crystallinity as SERS substrates. Polymorphous TiO2/CNF thin films with well-defined morphology are obtained by combining atomic layer deposition and thermal annealing. A high enhancement factor of 1.79 × 106 in terms of semiconductor metal oxide nanomaterial (SMON)-based SERS substrates is obtained from the annealed TiO2/CNF thin films with a TiO2 layer thickness of 10 nm fabricated on indium tin oxide (ITO), when probed by 4-mercaptobenzoic acid molecules. Common SERS probes down to 10 nm can be detected on these TiO2/CNF substrates, indicating superior sensitivity of TiO2/CNF thin films among SMON SERS substrates. This improvement in SERS sensitivity is realized through a cooperative modulation of the template morphology of the CNF network and the crystalline state of TiO2.
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| 49. |
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| 50. |
- Heldbjerg, Henning, et al.
(författare)
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Contrasting population trends of common starlings (Sturnus vulgaris) across Europe
- 2019
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Ingår i: Ornis Fennica. - 0030-5685. ; 96:4, s. 153-168
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Tidskriftsartikel (refereegranskat)abstract
- The greatest loss of biodiversity in the EU has occurred on agricultural land. The Common Starling (Sturnus vulgaris) is one of the many numerous and widespread European farmland breeding bird species showing major population declines linked to European agricultural intensification. Here we present results based on monitoring data collected since 1975 in 24 countries to examine the influence of changing extent of grassland and cattle abundance (based on results of earlier studies showing the importance of lowland cattle grazed grassland for the species), wintering provenance and temperature on national breeding population trends of Starlings across Europe. Positive Starling population trends in Central-East Europe contrast with negative trends in North and West Europe. Based on this indicative approach, we found some support for the importance of cattle stock and no support for grassland, temperature or wintering provenance to explain Starling population trends in Europe. However, we acknowledge such a European-wide analysis may conceal regional differences in responses and suggest that currently accessible national land use data might be insufficient to describe the detailed current changes in animal husbandry and grassland management that may be responsible for changes in food availability and hence breeding Starling abundance and their differences across Europe. Reviewing results from local studies relating Starling population trends to local agricultural change offer contradictory results, suggesting complex interacting processes at work. We recommend combining national datasets on demography, land-use/agricultural practices and from autecological research to better explain the reasons for contrasting Starling trends across Europe, to enable us to predict how changing agriculture will affect Starlings and potentially suggest mitigation measures to restore local populations where possible.
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