414 research outputs found
Unsolicited written narratives as a methodological genre in terminal illness: challenges and limitations
Stories about illness have proven invaluable in helping health professionals understand illness experiences. Such narratives have traditionally been solicited by researchers through interviews and the collection of personal writings, including diaries. These approaches are, however, researcher driven; the impetus for the creation of the story comes from the researcher and not the narrator. In recent years there has been exponential growth in illness narratives created by individuals, of their own volition, and made available for others to read in print or as Internet accounts. We sought to determine whether it was possible to identify such material for use as research data to explore the subject of living with the terminal illness amyotrophic lateral sclerosis/motor neuron disease—the contention being that these accounts are narrator driven and therefore focus on issues of greatest importance to the affected person. We encountered and sought to overcome a number of methodological and ethical challenges, which is our focus here
Spectroscopy of neutron-unbound F
The ground state of F has been observed as an unbound resonance
keV above the ground state of F. Comparison of this
result with USDA/USDB shell model predictions leads to the conclusion that the
F ground state is primarily dominated by -shell configurations. Here
we present a detailed report on the experiment in which the ground state
resonance of F was first observed. Additionally, we report the first
observation of a neutron-unbound excited state in F at an excitation
energy of keV.Comment: 10 pages, 11 figures, Accepted for publication in Phys. Rev.
Observation of isotonic symmetry for enhanced quadrupole collectivity in neutron-rich 62,64,66Fe isotopes at N=40
The transition rates for the 2_{1}^{+} states in 62,64,66Fe were studied
using the Recoil Distance Doppler-Shift technique applied to projectile Coulomb
excitation reactions. The deduced E2 strengths illustrate the enhanced
collectivity of the neutron-rich Fe isotopes up to N=40. The results are
interpreted by the generalized concept of valence proton symmetry which
describes the evolution of nuclear structure around N=40 as governed by the
number of valence protons with respect to Z~30. The deformation suggested by
the experimental data is reproduced by state-of-the-art shell calculations with
a new effective interaction developed for the fpgd valence space.Comment: 4 pages, 2 figure
Probing elastic and inelastic breakup contributions to intermediate-energy two-proton removal reactions
The two-proton removal reaction from 28Mg projectiles has been studied at 93
MeV/u at the NSCL. First coincidence measurements of the heavy 26Ne projectile
residues, the removed protons and other light charged particles enabled the
relative cross sections from each of the three possible elastic and inelastic
proton removal mechanisms to be determined. These more final-state-exclusive
measurements are key for further interrogation of these reaction mechanisms and
use of the reaction channel for quantitative spectroscopy of very neutron-rich
nuclei. The relative and absolute yields of the three contributing mechanisms
are compared to reaction model expectations - based on the use of eikonal
dynamics and sd-shell-model structure amplitudes.Comment: Accepted for publication in Physical Review C (Rapid Communication
Elastic breakup cross sections of well-bound nucleons
The 9Be(28Mg,27Na) one-proton removal reaction with a large proton separation
energy of Sp(28Mg)=16.79 MeV is studied at intermediate beam energy.
Coincidences of the bound 27Na residues with protons and other light charged
particles are measured. These data are analyzed to determine the percentage
contributions to the proton removal cross section from the elastic and
inelastic nucleon removal mechanisms. These deduced contributions are compared
with the eikonal reaction model predictions and with the previously measured
data for reactions involving the re- moval of more weakly-bound protons from
lighter nuclei. The role of transitions of the proton between different bound
single-particle configurations upon the elastic breakup cross section is also
quantified in this well-bound case. The measured and calculated elastic breakup
fractions are found to be in good agreement.Comment: Phys. Rev. C 2014 (accepted
Correlations in intermediate-energy two-proton removal reactions
We report final-state-exclusive measurements of the light charged fragments
in coincidence with 26Ne residual nuclei following the direct two-proton
removal from a neutron-rich 28Mg secondary beam. A Dalitz-plot analysis and
comparisons with simulations show that a majority of the triple- coincidence
events with two protons display phase-space correlations consistent with the
(two-body) kinematics of a spatially-correlated pair-removal mechanism. The
fraction of such correlated events, 56(12) %, is consistent with the fraction
of the calculated cross section, 64 %, arising from spin S = 0 two-proton
configurations in the entrance-channel (shell-model) 28Mg ground state wave
function. This result promises access to an additional and more specific probe
of the spin and spatial correlations of valence nucleon pairs in exotic nuclei
produced as fast secondary beams.Comment: accepted for publication in Physical Review Letter
Exploring the Low- Shore of the Island of Inversion at
The technique of invariant mass spectroscopy has been used to measure, for
the first time, the ground state energy of neutron-unbound
determined to be a resonance in the continuum at
keV. States in were
populated by the reactions of a 62 MeV/u beam impinging on a
288 beryllium target. The measured ground
state energy is in good agreement with USDA/USDB shell model predictions,
indicating that shell intruder configurations play only a small role in
the ground state structure of and establishing a low-
boundary of the island of inversion for N=19 isotones.Comment: 5 pages, 4 figures, to be published in Phys. Rev. Let
Tests of Micro-Pattern Gaseous Detectors for Active Target Time Projection Chambers in nuclear physics
Active target detection systems, where the gas used as the detection medium is also a target for nuclear reactions, have been used for a wide variety of nuclear physics applications since the eighties. Improvements in Micro-Pattern Gaseous Detectors (MPGDs) and in micro-electronics achieved in the last decade permit the development of a new generation of active targets with higher granularity pad planes that allow spatial and time information to be determined with unprecedented accuracy. A novel active target and time projection chamber (ACTAR TPC), that will be used to study reactions and decays of exotic nuclei at facilities such as SPIRAL2, is presently under development and will be based on MPGD technology. Several MPGDs (Micromegas and Thick GEM) coupled to a 2×2 mm2 pixelated pad plane have been tested and their performances have been determined with different gases over a wide range of pressures. Of particular interest for nuclear physics experiments are the angular and energy resolutions. The angular resolution has been determined to be better than 1° FWHM for short traces of about 4 cm in length and the energy resolution deduced from the particle range was found to be better than 5% for 5.5 MeV α particles. These performances have been compared to Geant4 simulations. These experimental results validate the use of these detectors for several applications in nuclear physics
Corporate governance and financial constraints on strategic turnarounds
The paper extends the Robbins and Pearce (1992) two-stage turnaround response model to include governance factors. In addition to the retrenchment and recovery, the paper proposes the addition of a realignment stage, referring specifically to the re-alignment of expectations of principal and agent groups. The realignment stage imposes a threshold that must be crossed before the retrenchment and hence recovery stage can be entered. Crossing this threshold is problematic to the extent that the interests of governance-stakeholder groups diverge in a crisis situation. The severity of the crisis impacts on the bases of strategy contingent asset valuation leading to the fragmentation of stakeholder interests. In some cases the consequence may be that management are prevented from carrying out turnarounds by governance constraints. The paper uses a case study to illustrate these dynamics, and like the Robbins and Pearce study, it focuses on the textile industry. A longitudinal approach is used to show the impact of the removal of governance constraints. The empirical evidence suggests that such financial constraints become less serious to the extent that there is a functioning market for corporate control. Building on governance research and turnaround literature, the paper also outlines the general case necessary and sufficient conditions for successful turnarounds
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