109 research outputs found
Single Proton Knock-Out Reactions from 24,25,26F
The cross sections of the single proton knock-out reactions from 24F, 25F,
and 26F on a 12C target were measured at energies of about 50 MeV/nucleon.
Ground state populations of 6.6+-.9 mb, 3.8+-0.6 mb for the reactions
12C(24F,23O) and 12C(25F,24O) were extracted, respectively. The data were
compared to calculations based on the many-body shell model and the eikonal
theory. In the reaction 12C(26F,25O) the particle instability of 25O was
confirmed
Nuclear vorticity and the low-energy nuclear response - Towards the neutron drip line
The transition density and current provide valuable insight into the nature
of nuclear vibrations. Nuclear vorticity is a quantity related to the
transverse transition current. In this work, we study the evolution of the
strength distribution, related to density fluctuations, and the vorticity
strength distribution, as the neutron drip line is approached. Our results on
the isoscalar, natural-parity multipole response of Ni isotopes, obtained by
using a self-consistent Skyrme-Hartree-Fock + Continuum RPA model, indicate
that, close to the drip line, the low-energy response is dominated by L>1
vortical transitions.Comment: 8 pages, incl. 4 figures; to appear in Phys.Lett.
Soft Dipole Modes in Neutron-rich Ni-isotopes in QRRPA
The soft dipole modes in neutron rich even-even Ni-isotopes are investigated
in the quasiparticle relativistic random phase approximation. We study the
evolution of strengths distribution, centroid energies of dipole excitation in
low-lying and normal GDR regions with the increase of the neutron excess. It is
found in the present study that the centroid energies of the soft dipole
strengths strongly depend on the thickness of neutron skin along with the
neutron rich even-even Ni-isotopes.Comment: 14 pages, 7 figure
Structure of the N=27 isotones derived from the Ar(d,p)Ar
Expérience GANIL/SPIRAL, détecteur CATS, détecteur MUST, 7 figures,International audienceThe Ar(d,p)Ar neutron transfer reaction was performed at 10~A.MeV. Measured excitation energies, deduced angular momenta and spectroscopic factors of the states populated in Ar are reported. A satisfactory description of these properties is achieved in the shell model framework using a new interaction. The model analysis is extended to more exotic even-Z nuclei down to Si to study how collectivity impacts the low lying structure of N~=~27 neutron-rich nuclei
Direct evidence of transfer with weakly bound isotopes of He near the Coulomb barrier and implications of fusion
NESTERPartial residue cross sections for fusion and transfer have been measured from the intensities of characteristic gamma-rays for the He + Cu systems at energies near the Coulomb barrier (Vb)
Crossing the Dripline to 11N Using Elastic Resonance Scattering
The level structure of the unbound nucleus 11N has been studied by 10C+p
elastic resonance scattering in inverse geometry with the LISE3 spectrometer at
GANIL, using a 10C beam with an energy of 9.0 MeV/u. An additional measurement
was done at the A1200 spectrometer at MSU. The excitation function above the
10C+p threshold has been determined up to 5 MeV. A potential-model analysis
revealed three resonance states at energies 1.27 (+0.18-0.05) MeV (Gamma=1.44
+-0.2 MeV), 2.01(+0.15-0.05) MeV, (Gamma=0.84 +-$0.2 MeV) and 3.75(+-0.05) MeV,
(Gamma=0.60 +-0.05 MeV) with the spin-parity assignments I(pi) =1/2+, 1/2- and
5/2+, respectively. Hence, 11N is shown to have a ground state parity inversion
completely analogous to its mirror partner, 11Be. A narrow resonance in the
excitation function at 4.33 (+-0.05) MeV was also observed and assigned
spin-parity 3/2-.Comment: 14 pages, 9 figures, twocolumn Accepted for publication in PR
De novo mutations in SMCHD1 cause Bosma arhinia microphthalmia syndrome and abrogate nasal development
Bosma arhinia microphthalmia syndrome (BAMS) is an extremely rare and striking condition characterized by complete absence of the nose with or without ocular defects. We report here that missense mutations in the epigenetic regulator SMCHD1 mapping to the extended ATPase domain of the encoded protein cause BAMS in all 14 cases studied. All mutations were de novo where parental DNA was available. Biochemical tests and in vivo assays in Xenopus laevis embryos suggest that these mutations may behave as gain-of-function alleles. This finding is in contrast to the loss-of-function mutations in SMCHD1 that have been associated with facioscapulohumeral muscular dystrophy (FSHD) type 2. Our results establish SMCHD1 as a key player in nasal development and provide biochemical insight into its enzymatic function that may be exploited for development of therapeutics for FSHD
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