'Gnosticism' in fourth century Britain: the Frampton mosaics reconsidered

Recent years have seen a renewed interest in the significance of the mosaic designs employed in Roman houses. Studies have concentrated on establishing the mythological sources of the images chosen, and on describing the social and architectural contexts within which such art was used. It has long been noted that some of the subjects preferred in fourth-century Britain suggest allegorical references to the hereafter, although it has also been observed that the ‘search for profound and coherent allegories may exaggerate the significance which the wealthy British patrons imparted to the floors of the great halls or dining-rooms of their villas’. Ling, in particular, has cautioned against reading exaggerated meanings into ambivalent images that may simply have been chosen to vaunt erudite taste

The making of Britain’s first urban landscapes: the case of late Iron Age and Roman Essex

This paper presents preliminary research into the social and economic impact of early urban settlement in Britain, focusing on the case-study area of Late Iron Age to Roman Essex. Through fresh analysis of ceramic assemblages from Colchester and Heybridge, we describe hitherto unrecognised socio-cultural groupings and identities through subtle differences in the deposition of pottery in the generations before and after conquest. The concluding discussion concentrates on problems that we still have to address in describing the economic basis of early urban society in Britain

Involving the public in archaeological fieldwork: how heritage protection policies do not always serve public interests

The history of Esgair Fraith is the story of just two families, of two sets of biographies. For almost fifty years Esgair Fraith lay deep in the Clwedog Forest, planted by the Forestry Commission between 1956 and 1959 in two adjoining parishes, and composed mainly of non-indigenous sitka spruce, with some pine. But it was never quite hidden. Everything at Esgair Fraith has recently changed. The cash-crop timber has been harvested, and the finds of this fellinga kind of excavation in itselfare spectacular: across this hillside a dozen similar derelict farms have emerged. Contemporary performance makes no attempt to re-enact the million, million things that have happened here; it may even in theoretical architect Bernard Tschumis terms be as much ambivalent to, or indeed in conflict with, the site as much as congruent or reciprocal with it; the relationship between the found place and the fabricated performance scenography may be assymetrical, one dominating the other

Two studies on Roman London

My intent is to advance some new suggestions (or rather, to revive some long unfashionable ones) concerning the origins and early development of the Roman town. Two under-reported discoveries of military-style ditches allow it to be suggested that London originated as a fort where the armies of Plautius awaited the emperor Claudius before marching on Colchester in the summer of A.D. 43. The alternative and prevailing view, that the city was a civilian foundation of c.A.D. 50, must be questioned. This in turn suggests a re-assessment of the rôle of London in the political infrastructure of the newly-created Roman province. It seems likely that London remained firmly under the control of the provincial government, and a major centre of operations for both army and administration. This finds confirmation in the recently-discovered evidence of fortifications and engineering works associated with extensive reconstruction in the aftermath of the Boudican revolt of A.D. 60/61

3-Dimensional simulation of multistage depressed collectors on microcomputers.

A three-dimensional (3-D) package for simulation of asymmetric and crossed-field multistage depressed collectors for microwave tubes has been developed. This package is based upon the 3-D finite-difference code KOBRA3-INP. The main features of the package are a user-friendly input interface, postprocessors for collector analysis and calculation of secondary electron trajectories, and versatile output graphics. Both PC and. mainframe versions of the package have been developed. The results of simple benchmark tests and those of simulation and analysis of asymmetric and crossed-field collectors including the effects of secondary electrons are presented. It is found that the asymmetric hyperbolic electric field collector shows very low backstreaming. It is shown that the representation of trajectories in energy space gives a better insight into the behavior of individual trajectories than plotting in coordinate-space. The package will be useful for designing novel types of depressed collector

Spin excitations used to probe the nature of the exchange coupling in the magnetically ordered ground state of Pr0.5_{0.5}Ca0.5_{0.5}MnO3_{3}

We have used time-of-flight inelastic neutron scattering to measure the spin wave spectrum of the canonical half-doped manganite Pr$_{0.5}$Ca$_{0.5}$MnO$_{3}$, in its magnetic and orbitally ordered phase. The data, which cover multiple Brillouin zones and the entire energy range of the excitations, are compared with several different models that are all consistent with the CE-type magnetic order, but arise through different exchange coupling schemes. The Goodenough model, i.e. an ordered state comprising strong nearest neighbor ferromagnetic interactions along zig-zag chains with antiferromagnetic inter-chain coupling, provides the best description of the data, provided that further neighbor interactions along the chains are included. We are able to rule out a coupling scheme involving formation of strongly bound ferromagnetic dimers, i.e. Zener polarons, on the basis of gross features of the observed spin wave spectrum. A model with weaker dimerization reproduces the observed dispersion but can be ruled out on the basis of discrepancies between the calculated and observed structure factors at certain positions in reciprocal space. Adding further neighbor interactions results in almost no dimerization, i.e. recovery of the Goodenough model. These results are consistent with theoretical analysis of the degenerate double exchange model for half-doping, and provide a recipe for how to interpret future measurements away from half-doping, where degenerate double exchange models predict more complex ground states.Comment: 14 pages, 11 figure