Dynamic instabilities in scalar neural field equations with space-dependent delays

In this paper we consider a class of scalar integral equations with a form of space-dependent delay. These non-local models arise naturally when modelling neural tissue with active axons and passive dendrites. Such systems are known to support a dynamic (oscillatory) Turing instability of the homogeneous steady state. In this paper we develop a weakly nonlinear analysis of the travelling and standing waves that form beyond the point of instability. The appropriate amplitude equations are found to be the coupled mean-field Ginzburg-Landau equations describing a Turing-Hopf bifurcation with modulation group velocity of O(1). Importantly we are able to obtain the coefficients of terms in the amplitude equations in terms of integral transforms of the spatio-temporal kernels defining the neural field equation of interest. Indeed our results cover not only models with axonal or dendritic delays but those which are described by a more general distribution of delayed spatio-temporal interactions. We illustrate the predictive power of this form of analysis with comparison against direct numerical simulations, paying particular attention to the competition between standing and travelling waves and the onset of Benjamin-Feir instabilities.

Reconfiguring or reproducing intra-professional boundaries? Specialist expertise, generalist knowledge and the ‘modernization’ of the medical workforce

Efforts to ‘modernize’ the clinical workforce of the English National Health Service have sought to reconfigure the responsibilities of professional groups in pursuit of more effective, joined-up service provision. Such efforts have met resistance from professions eager to protect their jurisdictions, deploying legitimacy claims familiar from the insights of the sociology of professions. Yet to date few studies of professional boundaries have grounded these insights in the specific context of policy challenges to the inter- and intra-professional division of labour, in relation the medical profession and other health-related occupations. In this paper we address this gap by considering the experience of newly instituted general practitioners (family physicians) with a special interest (GPSIs) in genetics, introduced to improve genetics knowledge and practice in primary care. Using qualitative data from four comparative case studies, we discuss how an established intra-professional division of labour within medicine—between clinical geneticists and GPs—was opened, negotiated and reclosed in these sites. We discuss the contrasting attitudes towards the nature of genetics knowledge and its application of GPSIs and geneticists, and how these were used to advance conflicting visions of what the nascent GPSI role should involve. In particular, we show how the claims to knowledge of geneticists and GPSIs interacted with wider policy pressures to produce a rather more conservative redistribution of power and responsibility across the intra-professional boundary than the rhetoric of modernization might suggest.

The ins and outs of biosecurity: bird 'flu in East Anglia and the spatial representation of risk

Avian influenza, or 'bird 'flu' arrived in Norfolk in April 2006 in the form of the low pathogenic strain H7N3. In February 2007 a highly pathogenic strain, H5N1, which can pose a risk to humans, was discovered in Suffolk. We examine how a local newspaper reported the outbreaks, focusing on the linguistic framing of biosecurity. Consistent with the growing concern with securitisation among policymakers, issues were discussed in terms of space (indoor–outdoor; local–global; national–international) and flows (movement, barriers and vectors) between spaces (farms, sheds and countries). The apportioning of blame along the lines of 'them and us'– Hungary and England – was tempered by the reporting on the Hungarian operations of the British poultry company. Explanations focused on indoor and outdoor farming and alleged breaches of biosecurity by the companies involved. As predicted by the idea of securitisation, risks were formulated as coming from outside the supposedly secure enclaves of poultry production.