Elastic alpha-scattering of 112Sn and 124Sn at astrophysically relevant energies

The cross sections for the elastic scattering reactions {112,124}Sn(a,a){112,124}Sn at energies above and below the Coulomb barrier are presented and compared to predictions for global alpha-nucleus potentials. The high precision of the new data allows a study of the global alpha-nucleus potentials at both the proton and neutron-rich sides of an isotopic chain. In addition, local alpha-nucleus potentials have been extracted for both nuclei, and used to reproduce elastic scattering data at higher energies. Predictions from the capture cross section of the reaction 112Sn(a,g)116Te at astrophysically relevant energies are presented and compared to experimental data.Comment: 20 pages, 10 figures, accepted for publication in Phys. Rev.

A solution to the zero-hamiltonian problem in 2-D gravity

The zero-hamiltonian problem, present in reparametrization invariant systems, is solved for the 2-D induced gravity model. Working with methods developed by Henneaux et al. we find systematically the reduced phase-space physics, generated by an {\it effective} hamiltonian obtained after complete gauge fixing.Comment: 5 pages, revte

Implementing changes to hospital services: factors influencing the process and 'results' of reconfiguration

OBJECTIVES: Acute hospital reconfiguration is often presented as a problem to be solved by calculations of optimal design, a rational process amenable to influence by open and responsive consultation. We aimed to analyse factors in the process and 'results' of hospital reconfiguration in three case study sites in the English NHS. METHODS: In-depth semi-structured interviews were conducted with internal and external stakeholders at each site. Analysis within each case was complemented by cross-case analysis focusing on the relationships between the features of the origins and process of reconfiguration and progress in the implementation of plans. FINDINGS: We identified a number of inter-related factors operating in the process of implementation which influenced the 'results': the drivers for change, the reconfiguration, its content (particularly the extent to which services are withdrawn or made less accessible), the influence of stakeholders, such as local politicians, financial pressures, and the role of the management team. CONCLUSIONS: We argue that the differences in reconfiguration implementation between the three cases reflected the nature of the proposed changes and local politics, rather than the strength of the 'evidence' for change. National policy has tended to over-emphasise the importance of consultation using 'evidence' and underplays these influencing factors

Influence of the radio frequency ponderomotive force on anomalous impurity transport in tokamaks

Trace impurity transport in tokamaks is studied using an electrostatic, collisionless fluid model for ion-temperature-gradient and trapped-electron mode driven turbulence in the presence of radio frequency (rf) fields, and the results are compared with neoclassical predictions. It is shown that the inward impurity convective velocity (pinch) that is usually obtained can be reduced by the rf fields, in particular close to the wave resonance location where the rf ponderomotive force may be significant. However, the impurity diffusivity and convective velocity are usually similarly affected by the ponderomotive force, and hence the steady-state impurity density peaking factor -∇nz/nz is only moderately affected by the rf fields

Comparison of the LUNA 3He(alpha,gamma)7Be activation results with earlier measurements and model calculations

Recently, the LUNA collaboration has carried out a high precision measurement on the 3He(alpha,gamma)7Be reaction cross section with both activation and on-line gamma-detection methods at unprecedented low energies. In this paper the results obtained with the activation method are summarized. The results are compared with previous activation experiments and the zero energy extrapolated astrophysical S factor is determined using different theoretical models.Comment: Accepted for publication in Journal of Physics

Knowledge management infrastructure to support quality improvement: A qualitative study of maternity services in four European hospitals

The influence of multilevel healthcare system interactions on clinical quality improvement (QI) is still largely unexplored. Through the lens of knowledge management (KM) theory, this study explores how hospital managers can enhance the conditions for clinical QI given the specific multilevel and professional interactions in various healthcare systems. The research used an in-depth multilevel analysis in maternity departments in four purposively sampled European hospitals (Portugal, England, Norway and Sweden). The study combines analysis of macro-level policy documents and regulations with semi-structured interviews (96) and non-participant observations (193 hours) of hospital and clinical managers and clinical staff in maternity departments. There are four main conclusions: First, the unique multilevel configuration of national healthcare policy, hospital management and clinical professionals influence the development of clinical QI efforts. Second, these different configurations provide various and often insufficient support and guidance which affect professionals’ action strategies in QI efforts. Third, hospital managers’ opportunities and capabilities for developing a consistent KM infrastructure with reinforcing enabling conditions which merge national policies and guidelines with clinical reality is crucial for clinical QI. Fourth, understanding these interrelationships provides an opportunity for improvement of the KM infrastructure for hospital managers through tailored interventions