Cultural measurement on whose terms? Critical friends as an experiment in participant-led evaluation

Critical Friends is an enquiry into the commissioning, planning and delivery of participatory art carried out by the people that such projects claim to empower. Participants become interviewers, researchers and evaluators, acting as ‘productive parasites’ to a process of socially-engaged art. Aims of social cohesion and active citizenship underpinned a series of publicly-funded art commissions in North Greenwich, London (2008-2011). The group of Critical Friends were residents of North Greenwich who came together to investigate what, why and how these socially engaged art projects were happening in their area. Did the projects reflect the ambitious aims to ‘stimulate debate to generate action and change’ and ‘develop connections and relations between people’? Facilitated by myself and Rebecca Maguire over three years, Critical Friends developed their own questions and methods for finding out. While participation and engagement is usually measured for such projects in terms of numbers of people who attend workshops, Critical Friends was a space for enacting a different kind of cultural measurement. The group focused on trying to find out the qualitative experiences of other participants and interrogated the underlying motives, targets and politics behind the commissions. They did this by acting as participant observers in the projects themselves and by interviewing artists, commissioners, board members, their neighbours and friends (http://criticalfriends.sophiehope.org.uk/)

The LHCb VELO upgrade

The LHCb experiment at the LHC plans to massively increase its data taking capabilities by running at a higher luminosity with a fully upgraded detector around 2016. This scheme is independent of (but compatible with) the plans for the SLHC upgrades. The silicon detector will be upgraded to provide a 40 MHz readout and to be able to cope with the increased radiation environment. This paper describes the options currently under consideration. A highlight of the R&D so far undertaken is a beam test during summer 2009 using the Timepix chip to track charged particles. Preliminary results are presented, including a measurement of the resolution achieved by the pitch pixel array of better than for perpendicular tracks and for angled tracks

Differential control of Eg5-dependent centrosome separation by Plk1 and Cdk1

Cyclin-dependent kinase 1 (Cdk1) is thought to trigger centrosome separation in late G2 phase by phosphorylating the motor protein Eg5 at Thr927. However, the precise control mechanism of centrosome separation remains to be understood. Here, we report that in G2 phase polo-like kinase 1 (Plk1) can trigger centrosome separation independently of Cdk1. We find that Plk1 is required for both C-Nap1 displacement and for Eg5 localization on the centrosome. Moreover, Cdk2 compensates for Cdk1, and phosphorylates Eg5 at Thr927. Nevertheless, Plk1-driven centrosome separation is slow and staggering, while Cdk1 triggers fast movement of the centrosomes. We find that actin-dependent Eg5-opposing forces slow down separation in G2 phase. Strikingly, actin depolymerization, as well as destabilization of interphase microtubules (MTs), is sufficient to remove this obstruction and to speed up Plk1-dependent separation. Conversely, MT stabilization in mitosis slows down Cdk1-dependent centrosome movement. Our findings implicate the modulation of MT stability in G2 and M phase as a regulatory element in the control of centrosome separation