17,027 research outputs found
Experiments in democratic participation: feminist printshop collectives
This article examines the output and practices of two London-based feminist printing collectives that operated between the 1970s to the early 1990s and for whom the principles of democratic participation and access were central. Their activities are discussed in relation to specific, changing and sometimes challenging politic-cultural contexts in which they existed
Effective Field Theory Treatment of Monopole Production by Drell-Yan and Photon Fusion for Various Spins
A resolution over the existence of magnetic charges has eluded the high
energy physics community for centuries, and their search has gained momentum as
recent models predict these may be observable at current colliders. They appear
in field theories in two forms: the widely studied but heavily suppressed
monopole with structure (soliton) and the not-so-well-covered point-like
monopole. The latter was first proposed by Dirac as the source of a singular
magnetic field and in effect symmetrises Maxwell's equations. Following this
line of research, work by S. Baines et al. analysed these sources as matter
fields that carry spins 0, , or 1, in an effective field theory
that is perturbative for monopoles produced at threshold where the coupling
strength is suppressed. All three cases are currently under
investigation by the MoEDAL collaboration at CERN, and the theoretical
expressions for kinematic distributions proposed in this work serve as guides
to these searches. The cross section distributions in each case are derived
from a \emph{U}(1) invariant gauge theory. It is not assumed that, like the
electron, the monopole's magnetic moment is generated through spin interactions
at minimal coupling, as it may be quite large. Instead, the analytical
expressions in the spin and cases are kept completely general
through the inclusion of a phenomenological parameter , related to the
gyromagnetic ratio . In fact, the inclusion of this parameter
gives the effective theory validity in the high energy limit if the magnetic
coupling scales with the particle's velocity .Comment: 11 pages, 14 figures, conference proceedin
Free Radicals
Commissioned article looking back at London's printmaking workshops of the 1960s and 70s, DIY sites of political and community activism that rejected the role of the artist to participate in a network of campaign groups, radical publishers and distributors
Postsynaptic protein kinase a reduces neuronal excitability in response to increased synaptic excitation in the Drosophila CNS
Previous work has identified a role for synaptic activity in the development of excitable properties of motoneurons in the Drosophila embryo. In this study the underlying mechanism that enables two such neurons, termed aCC and RP2, to respond to increased exposure to synaptic excitation is characterized. Synaptic excitation is increased in genetic backgrounds that lack either a cAMP-specific phosphodiesterase (EC:3.1.4, dunce) or acetylcholinesterase (EC:3.1.1.7, ace), the enzyme that terminates the endogenous cholinergic excitation of these motoneurons. Analysis of membrane excitability in aCC/RP2, in either background, shows that these neurons have a significantly reduced capability to fire action potentials (APs) in response to injection of depolarizing current. Analysis of underlying voltage-gated currents show that this effect is associated with a marked reduction in magnitude of the voltage-dependent inward Na+ current (INa). Partially blocking INa in these motoneurons, using low concentrations of TTX, demonstrates that a reduction of INa is, by itself, sufficient to reduce membrane excitability. An analysis of firing implicates an increased AP threshold to underlie the reduction in membrane excitability observed because of heightened exposure to synaptic excitation. Genetic or pharmacological manipulations that either elevate cAMP or increase protein kinase A (PKA) activity in wild-type aCC/RP2 mimic both the reductions in membrane excitability and INa. In comparison, increasing cAMP catabolism or inhibition of PKA activity is sufficient to block the induction of these activity-dependent changes. The induced changes in excitability can be rapid, occurring within 5 min of exposure to a membrane-permeable cAMP analog, indicative that threshold can be regulated in these neurons by a post-translational mechanism that is dependent on phosphorylation
Recommended from our members
Ethnicity
As developed in the fields of anthropology and sociology, the concept of ethnicity offers one possible approach to analyzing diversity in the population of ancient Egypt. However, it is important that ethnicity not be elided with foreign-ness, as has often been the case in Egyptological literature. Ethnicity is a social construct based on self-image, and thus may be difficult to identify in the ancient sources, where a monolithic uniformity of “Egyptian” versus “other” prevails. A range of sources does suggest that ethnic difference operated within the indigenous population throughout Egyptian history, as would be expected in any complex society. This discussion explores these sources and suggests ways of thinking about the negotiation of ethnic identity in ancient Egypt
‘At Least I Can Do Something’: The Work of Volunteering in a Community Beset by Worklessness
The voluntary sector has been mainstreamed into public policy with consequences that include more reliance upon the time, commitment and skills of volunteers. In many policy initiatives to combat social exclusion, volunteering is cast as a form of self-improvement and re-training for the workforce. Qualitative research in a disadvantaged community, however, uncovered the persistence of more traditional forms of volunteering associated with mutual support and identification with the needs of others. Policies intended to broaden the base of the volunteer workforce need to recognise and nurture the intrinsic rewards of volunteering
Made to serve: a model of the operations practices and technologies that deliver servitization
This paper explores how successfully servitised manufacturers deliver advanced services and proposes a model that describes how they configure their operations. A case study methodology is applied across four manufacturing organisations successful in delivering advanced services. A descriptive model is then formed based around six popular technologies and practices
- …