In the kingdom of the blind: successfully implementing institutional repositories in the UK and the SHERPA Partnership experience

This paper takes an overview of the work of SHERPA team and the SHERPA Partnership institutions in the area of developing, populating and maintaining institutional open access repositories. Crucial to this work has been the development of mutually supporting and enabling Partnership community, something which has been now recognised as needed by institutions who lie outside of it. To this end SHERPA is involved in efforts to support the individuals and institutions across the UK and Europe whom are engaging with the open access agenda on a practical level; through setting up community networks and disseminating experience. Key in the experience of the Partnership has been the role of advocacy of open access and repositories to the institutional research community. Whilst this experience has been unique to each institution, there are many shared lessons and best practice that the Partnership has recently reflected on, and that are articulated within this paper. Finally brief coverage on some of the vital community tools developed and maintained by SHERPA, and reflections on the evolving direction of open access in the UK are made.

Neuronal networks with gap junctions: A study of piece-wise linear planar neuron models

The presence of gap junction coupling among neurons of the central nervous systems has been appreciated for some time now. In recent years there has been an upsurge of interest from the mathematical community in understanding the contribution of these direct electrical connections between cells to large-scale brain rhythms. Here we analyze a class of exactly soluble single neuron models, capable of producing realistic action potential shapes, that can be used as the basis for understanding dynamics at the network level. This work focuses on planar piece-wise linear models that can mimic the firing response of several different cell types. Under constant current injection the periodic response and phase response curve (PRC) is calculated in closed form. A simple formula for the stability of a periodic orbit is found using Floquet theory. From the calculated PRC and the periodic orbit a phase interaction function is constructed that allows the investigation of phase-locked network states using the theory of weakly coupled oscillators. For large networks with global gap junction connectivity we develop a theory of strong coupling instabilities of the homogeneous, synchronous and splay state. For a piece-wise linear caricature of the Morris-Lecar model, with oscillations arising from a homoclinic bifurcation, we show that large amplitude oscillations in the mean membrane potential are organized around such unstable orbits.