234 research outputs found
Spectroscopy of 13B via the 13C(t,3He) reaction at 115 AMeV
Gamow-Teller and dipole transitions to final states in 13B were studied via
the 13C(t,3He) reaction at Et = 115 AMeV. Besides the strong Gamow-Teller
transition to the 13B ground state, a weaker Gamow-Teller transition to a state
at 3.6 MeV was found. This state was assigned a spin-parity of 3/2- by
comparison with shell-model calculations using the WBP and WBT interactions
which were modified to allow for mixing between nhw and (n+2)hw configurations.
This assignment agrees with a recent result from a lifetime measurement of
excited states in 13B. The shell-model calculations also explained the
relatively large spectroscopic strength measured for a low-lying 1/2+ state at
4.83 MeV in 13B. The cross sections for dipole transitions up to Ex(13B)= 20
MeV excited via the 13C(t,3He) reaction were also compared with the shell-model
calculations. The theoretical cross sections exceeded the data by a factor of
about 1.8, which might indicate that the dipole excitations are "quenched".
Uncertainties in the reaction calculations complicate that interpretation.Comment: 11 pages, 6 figure
Rethinking globalised resistance : feminist activism and critical theorising in international relations
This article argues that a feminist approach to the 'politics of resistance' offers a number of important empirical insights which, in turn, open up lines of theoretical inquiry which critical theorists in IR would do well to explore. Concretely, we draw on our ongoing research into feminist 'anti-globalisation' activism to rethink the nature of the subject of the politics of resistance, the conditions under which resistance emerges and how resistance is enacted and expressed. We begin by discussing the relationship of feminism to critical IR theory as a way of situating and explaining the focus and approach of our research project. We then summarise our key empirical arguments regarding the emergence, structure, beliefs, identities and practices of feminist 'anti-globalisation' activism before exploring the implications of these for a renewed critical theoretical agenda in IR
Beta-delayed proton emission in the 100Sn region
Beta-delayed proton emission from nuclides in the neighborhood of 100Sn was
studied at the National Superconducting Cyclotron Laboratory. The nuclei were
produced by fragmentation of a 120 MeV/nucleon 112Sn primary beam on a Be
target. Beam purification was provided by the A1900 Fragment Separator and the
Radio Frequency Fragment Separator. The fragments of interest were identified
and their decay was studied with the NSCL Beta Counting System (BCS) in
conjunction with the Segmented Germanium Array (SeGA). The nuclei 96Cd, 98Ing,
98Inm and 99In were identified as beta-delayed proton emitters, with branching
ratios bp = 5.5(40)%, 5.5+3 -2%, 19(2)% and 0.9(4)%, respectively. The bp for
89Ru, 91,92Rh, 93Pd and 95Ag were deduced for the first time with bp = 3+1.9
-1.7%, 1.3(5)%, 1.9(1)%, 7.5(5)% and 2.5(3)%, respectively. The bp = 22(1)% for
101Sn was deduced with higher precision than previously reported. The impact of
the newly measured bp values on the composition of the type-I X-ray burst ashes
was studied.Comment: 15 pages, 14 Figures, 4 Table
On the extraction of weak transition strengths via the (3He,t) reaction at 420 MeV
Differential cross sections for transitions of known weak strength were
measured with the (3He,t) reaction at 420 MeV on targets of 12C, 13C, 18O,
26Mg, 58Ni, 60Ni, 90Zr, 118Sn, 120Sn and 208Pb. Using this data, it is shown
the proportionalities between strengths and cross sections for this probe
follow simple trends as a function of mass number. These trends can be used to
confidently determine Gamow-Teller strength distributions in nuclei for which
the proportionality cannot be calibrated via beta-decay strengths. Although
theoretical calculations in distorted-wave Born approximation overestimate the
data, they allow one to understand the main experimental features and to
predict deviations from the simple trends observed in some of the transitions.Comment: 4 pages, 2 figure
The Nd(He,) and Sm(,He) reactions with applications to decay of Nd
The Nd(He,) reaction at 140 MeV/u and Sm(,He)
reaction at 115 MeV/u were measured, populating excited states in Pm.
The transitions studied populate intermediate states of importance for the
(neutrinoless) decay of Nd to Sm. Monopole and
dipole contributions to the measured excitation-energy spectra were extracted
by using multipole decomposition analyses. The experimental results were
compared with theoretical calculations obtained within the framework of
Quasiparticle Random-Phase Approximation (QRPA), which is one of the main
methods employed for estimating the half-life of the neutrinoless
decay () of Nd. The present results thus provide useful
information on the neutrino responses for evaluating the and
matrix elements. The matrix element
calculated from the Gamow-Teller transitions through the lowest state
in the intermediate nucleus is maximally about half of that deduced from the
half-life measured in direct counting experiments and at least
several transitions through intermediate states in Pm are
required to explain the half-life.
Because Gamow-Teller transitions in the Sm(,He) experiment are
strongly Pauli-blocked, the extraction of Gamow-Teller strengths was
complicated by the excitation of the , ,
isovector spin-flip giant monopole resonance (IVSGMR). However, the near
absence of Gamow-Teller transition strength made it possible to cleanly
identify this resonance, and the strength observed is consistent with the full
exhaustion of the non-energy-weighted sum rule for the IVSGMR.Comment: 18 pages, 13 figures, 2 table
The early development of self-injurious behaviour: evaluating the role of social reinforcement
Background: The potential role of social reinforcement in the development of selfâinjury has not yet been subjected to empirical analysis. In this 2âyear prospective study, the pattern of social interactions related to the early presentation of selfâinjury were examined to identify a potential association with an increase in selfâinjury.
Methods: The selfâinjurious behaviour and social contact with adults of 16 children with intellectual disability (ID) with selfâinjury of recent onset were observed at 3âmonth intervals over 2âyears.
Results: Increase in selfâinjury over a 2âyear period was positively correlated with a distribution of social contact relative to episodes of selfâinjury that is consistent with a mutual social reinforcement paradigm. When this paradigm was operative, selfâinjury was evoked under stable antecedent conditions over time but tended to evoke increasing levels of social interaction.
Conclusions: These results support the hypothesis that increases in the frequency of early selfâinjury in children with ID may be determined by social reinforcement with implications for early intervention and proactive identification of children at risk for increases in selfâinjury
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