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Träfflista för sökning "WFRF:(Knobel H.) "

Sökning: WFRF:(Knobel H.)

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  • Caesar, C., et al. (författare)
  • Beyond the neutron drip line: The unbound oxygen isotopes O-25 and O-26
  • 2013
  • Ingår i: Physical Review C - Nuclear Physics. - 0556-2813 .- 1089-490X. ; 88:3
  • Tidskriftsartikel (refereegranskat)abstract
    • The very neutron-rich oxygen isotopes O-25 and O-26 are investigated experimentally and theoretically. The unbound states are populated in an experiment performed at the R3B-LAND setup at GSI via proton-knockout reactions from F-26 and F-27 at relativistic energies around 442 and 414 MeV/nucleon, respectively. From the kinematically complete measurement of the decay into O-24 plus one or two neutrons, the O-25 ground-state energy and width are determined, and upper limits for the O-26 ground-state energy and lifetime are extracted. In addition, the results provide indications for an excited state in O-26 at around 4 MeV. The experimental findings are compared to theoretical shell-model calculations based on chiral two- and three-nucleon (3N) forces, including for the first time residual 3N forces, which are shown to be amplified as valence neutrons are added.
  • Heine, M., et al. (författare)
  • Determination of the neutron-capture rate of C-17 for r-process nucleosynthesis
  • 2017
  • Ingår i: Physical Review C. - 2469-9985. ; 95:1, s. Article no 014613
  • Tidskriftsartikel (refereegranskat)abstract
    • With the (RB)-B-3-LAND setup at GSI we have measured exclusive relative-energy spectra of the Coulomb dissociation of C-18 at a projectile energy around 425A MeV on a lead target, which are needed to determine the radiative neutron-capture cross sections of C-17 into the ground state of C-18. Those data have been used to constrain theoretical calculations for transitions populating excited states in C-18. This allowed to derive the astrophysical cross section sigma(n gamma)*. accounting for the thermal population of C-17 target states in astrophysical scenarios. The experimentally verified capture rate is significantly lower than those of previously obtained Hauser-Feshbach estimations at temperatures T-9
  • Brinkman, Paul, et al. (författare)
  • Identification and prospective stability of electronic nose (eNose)-derived inflammatory phenotypes in patients with severe asthma
  • 2019
  • Ingår i: Journal of Allergy and Clinical Immunology. - Elsevier. - 0091-6749. ; 143:5, s. 1811-1820.e7
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Severe asthma is a heterogeneous condition, as shown by independent cluster analyses based on demographic, clinical, and inflammatory characteristics. A next step is to identify molecularly driven phenotypes using “omics” technologies. Molecular fingerprints of exhaled breath are associated with inflammation and can qualify as noninvasive assessment of severe asthma phenotypes.Objectives: We aimed (1) to identify severe asthma phenotypes using exhaled metabolomic fingerprints obtained from a composite of electronic noses (eNoses) and (2) to assess the stability of eNose-derived phenotypes in relation to withinpatient clinical and inflammatory changes.Methods: In this longitudinal multicenter study exhaled breath samples were taken from an unselected subset of adults with severe asthma from the U-BIOPRED cohort. Exhaled metabolites were analyzed centrally by using an assembly of eNoses. Unsupervised Ward clustering enhanced by similarity profile analysis together with K-means clustering was performed. For internal validation, partitioning around medoids and topological data analysis were applied. Samples at 12 to 18 months of prospective follow-up were used to assess longitudinal within-patient stability.Results: Data were available for 78 subjects (age, 55 years [interquartile range, 45-64 years]; 41% male). Three eNosedriven clusters (n = 26/33/19) were revealed, showing differences in circulating eosinophil (P = .045) and neutrophil (P = .017) percentages and ratios of patients using oral corticosteroids (P = .035). Longitudinal within-patient cluster stability was associated with changes in sputum eosinophil percentages (P = .045).Conclusions: We have identified and followed up exhaled molecular phenotypes of severe asthma, which were associated with changing inflammatory profile and oral steroid use. This suggests that breath analysis can contribute to the management of severe asthma.
  • Kanungo, R., et al. (författare)
  • Matter radii of 32-35Mg
  • 2011
  • Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 83:2, s. 021302-1-021302-4
  • Tidskriftsartikel (refereegranskat)abstract
    • The interaction cross sections of 32−35Mg at 900A MeV have been measurmed using the fragment separator at GSI. The deviation from the r0A1/3 trend is slightly larger for 35Mg, signaling the possible formation of a longer tail in the neutron distribution for 35Mg. The radii extracted from a Glauber model analysis with Fermi densities are consistent with models predicting the development of neutron skins.
  • Kanungo, R., et al. (författare)
  • One-Neutron Removal Measurement Reveals O-24 as a New Doubly Magic Nucleus
  • 2009
  • Ingår i: Physical Review Letters. - 1079-7114 .- 0031-9007. ; 102:15
  • Tidskriftsartikel (refereegranskat)abstract
    • The first measurement of the momentum distribution for one-neutron removal from O-24 at 920A MeV performed at GSI, Darmstadt is reported. The observed distribution has a width (FWHM) of 99 +/- 4 MeV/c in the projectile rest frame and a one-neutron removal cross section of 63 +/- 7 mb. The results are well explained with a nearly pure 2s(1/2) neutron spectroscopic factor of 1.74 +/- 0.19 within the eikonal model. This large s-wave probability shows a spherical shell closure thereby confirming earlier suggestions that O-24 is a new doubly magic nucleus.
  • Kanungo, R., et al. (författare)
  • Structure of Mg-33 sheds new light on the N=20 island of inversion
  • 2010
  • Ingår i: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - 0370-2693. ; 685:4-5, s. 253-257
  • Tidskriftsartikel (refereegranskat)abstract
    • The first reaction spectroscopy oil the ground state structure of Mg-33 through the measurement of the longitudinal momentum distribution from the one-neutron removal reaction Using a C target at 898A MeV is reported The experiment was performed at the FRS, GSI The distribution has a relatively narrow width (150 +/- 3 MeV/c (FWHM)) and the one-neutron removal cross-section is 74 +/- 4 mb An increased contribution from the (2)p(3/2) orbital is required to explain the observation showing its lowering compared to existing model predictions This provides new information regarding the configuration of Mg-33 and the island of inversion (C) 2010 Elsevier B V All rights reserved
  • Kostyleva, D., et al. (författare)
  • Towards the Limits of Existence of Nuclear Structure: Observation and First Spectroscopy of the Isotope K-31 by Measuring Its Three-Proton Decay
  • 2019
  • Ingår i: Physical Review Letters. - 1079-7114 .- 0031-9007. ; 123:9
  • Tidskriftsartikel (refereegranskat)abstract
    • The most remote isotope from the proton dripline (by 4 atomic mass units) has been observed: K-31. It is unbound with respect to three-proton (3p) emission, and its decays have been detected in flight by measuring the trajectories of all decay products using microstrip detectors. The 3p emission processes have been studied by the means of angular correlations of S-28 + 3p and the respective decay vertices. The energies of the previously unknown ground and excited states of K-31 have been determined. This provides its 3p separation energy value S-3p of -4.6(2) MeV. Upper half-life limits of 10 ps of the observed K-31 states have been derived from distributions of the measured decay vertices.
  • Mukha, I. G., et al. (författare)
  • Deep excursion beyond the proton dripline. I. Argon and chlorine isotope chains
  • 2018
  • Ingår i: Physical Review C. - 24699993 .- 24699985. ; 98:6
  • Tidskriftsartikel (refereegranskat)abstract
    • The proton-unbound argon and chlorine isotopes have been studied by measuring trajectories of their decay-in-flight products by using a tracking technique with microstrip detectors. The proton (1p) and two-proton (2p) emission processes have been detected in the measured angular correlations "heavy-fragment"+p and "heavy-fragment"+p+p, respectively. The ground states of the previously unknown isotopes Cl30 and Cl28 have been observed for the first time, providing the 1p-separation energies Sp of -0.48(2) and -1.60(8), MeV, respectively. The relevant systematics of 1p- and 2p-separation energies have been studied theoretically in the core+p and core+p+p cluster models. The first-time observed excited states of Ar31 allow one to infer the 2p-separation energy S2p of 6(34) keV for its ground state. The first-time observed state in Ar29 with S2p=-5.50(18) MeV can be identified as either a ground state or an excited state according to different systematics.
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