Spectral fiber dosimetry with beryllium oxide for quality assurance in hadron radiation therapy

Using the radioluminescence light of solid state probes coupled to long and flexible fibers for dosimetry in radiotherapy offers many advantages in terms of probe size, robustness and cost efficiency. However, especially in hadron fields, radioluminophores exhibit quenching effects dependent on the linear energy transfer. This work describes the discovery of a spectral shift in the radioluminescence light of beryllium oxide in dependence on the residual range at therapeutic proton energies. A spectrally resolving measurement setup has been developed and tested in scanned proton fields. It is shown that such a system can not only quantitatively reconstruct the dose, but might also give information on the residual proton range at the point of measurement

The possible experts: how epistemic communities negotiate barriers to knowledge use in ecosystems services policy

notes: This paper is based on research carried out with the support of the European Research Council grant on Analysis of Learning in Regulatory Governance, ALREG http://centres.exeter.ac.uk/ceg/research/ALREG/index.php. The author wishes to thank the other authors in this special edition and in particular the issue editors Andy Jordan and Duncan Russel.publication-status: AcceptedClaire A Dunlop, 2014. The definitive, peer-reviewed and edited version of this article is published in Environment and Planning C: Government and Policy, 32(2), 2014.The increased saliency of how to value ecosystems services has driven up the demand for policy-relevant knowledge. It is clear that epistemic communities’ advice can show-up in policy outcomes, yet little systematic analysis exists prescribing how this can actually be achieved. This article draws on four decades of knowledge utilisation research to propose four types of ‘possible expert’ that might be influential on ecosystems services. The first section reports the broad findings of a literature review on knowledge use in public policy, and outlines the four-fold conceptualisation pioneered by Carol Weiss that defines the literature. Section two systematises the field by placing these four modes of knowledge use within an explanatory typology of policy learning. With how, when and why experts and their knowledge are likely to show-up in policy outcomes established, the article then proposes the boundaries of the possible in how the ecosystems services epistemic community might navigate the challenges associated with each learning mode. Four possible experts emerge. The expert with: political antenna and epistemic humility; the ability to speak locally and early to the hearts and minds of citizens; a willingness to advocate policy, and, finally, an enhanced institutional awareness and peripheral policy vision. The article concludes with a brief discussion of the utility of the analysis.European Research Counci

New East Manchester: urban renaissance or urban opportunism?

In this paper we ask how a shrinking city responds when faced with a perforated urban fabric. Drawing on Manchester’s response to its perforated eastern flank - and informed by a parallel study of Leipzig - we use the city’s current approach to critique urban regeneration policy in England. Urban renaissance holds out the promise of delivering more sustainable - that is more compact, more inclusive and more equitable - cities. However, the Manchester study demonstrated that the attempt to stem population loss from the city is at best fragile, despite a raft of policies now in place to support urban renaissance in England. It is argued here that Manchester like Leipzig is likely to face an ongoing battle to attract residents back from their suburban hinterlands. This is especially true of the family market that we identify as being an important element for long-term sustainable population growth in both cities. We use the case of New East Manchester to consider how discourses linked to urban renaissance – particularly those that link urbanism with greater densities - rule out some of the options available to Leipzig, namely, managing the long-term perforation of the city. We demonstrate that while Manchester is inevitably committed to the urban renaissance agenda, in practice New East Manchester demonstrates a far more pragmatic – but equally unavoidable – approach. This we attribute to the gap between renaissance and regeneration described by Amin et al (2000) who define the former as urbanism for the middle class and the latter as urbanism for the working class. While this opportunistic approach may ultimately succeed in producing development on the ground, it will not address the fundamental, and chronic, problem; the combination of push and pull that sees families relocating to suburban areas. Thus, if existing communities in East Manchester are to have their area buoyed up – or sustained - by incomers, and especially families, with greater levels of social capital and higher incomes urban policy in England will have to be challenged

Diamagnetic shift of disorder-localized excitons in narrow GaAs/AlGaAs quantum wells

A correlation between the diamagnetic shift and transition energy of disorder-localized excitons is observed in magnetomicrophotoluminescence (mu PL) on narrow GaAs/Al0.3Ga0.7As quantum wells (QW's). The QW's were grown by molecular-beam epitaxy without growth interruption at the interfaces. mu PL spectra were obtained in a confocal setup with the magnetic field applied normal to the QW plane. The lowest-energy exciton states have the smallest diamagnetic coefficients; the exciton diamagnetic shift in the localized exciton tail of the QW emission spectra increases by a factor of 2 as a function of transition energy. The positive correlation between diamagnetic shift and emission energy reveals exciton localization by short-range correlated interface disorder