Gas-phase rate coefficients for the reactions of O(3P), S(3P), Se(3P), and Te(3P) with alkenes: application of perturbation frontier molecular orbital theory, correlations, and structure-activity relations (SARs)

The kinetics of the reactions of the atoms O(P-3), S(P-3), Se(P-3), and Te((3)p) with a series of alkenes are examined for correlations relating the logarithms of the rate coefficients to the energies of the highest occupied molecular orbitals (HOMOs) of the alkenes. These correlations may be employed to predict rate coefficients from the calculated HOMO energy of any other alkene of interest. The rate coefficients obtained from the correlations were used to formulate structure-activity relations (SARs) for reactions of O((3)p), S(P-3), Se (P-3), and Te((3)p) with alkenes. A comparison of the values predicted by both the correlations and the SARs with experimental data where they exist allowed us to assess the reliability of our method. We demonstrate the applicability of perturbation frontier molecular orbital theory to gas-phase reactions of these atoms with alkenes. The correlations are apparently not applicable to reactions of C(P-3), Si(P-3), N(S-4), and Al(P-2) atoms with alkenes, a conclusion that could be explained in terms of a different mechanism for reaction of these atoms.

The later Anglo-Saxon settlement at Bishopstone. A downland manor in the making

This volume reports on the excavations from 2002 to 2005 designed to investigate this transition, with the focus on the origins of Bishopstone village. Excavations adjacent to St Andrew’s churchyard revealed a dense swathe of later Anglo-Saxon (8th- to late 10th-/early 11th-century) habitation, including a planned complex of ‘timber halls’, and a unique cellared tower. The occupation encroached upon a pre-Conquest cemetery of 43 inhumations. The report provides a comprehensive analysis, interpretation and academic contextualisation of the archaeological discoveries brought to light by these excavations, the first to sample a later Anglo-Saxon rural settlement in East Sussex on an extensive scale. The inter-disciplinary approach appraises the historical and topographical evidence alongside that recovered during the excavations.

Detecting the environmental impact of the Baltic Crusades on a late-medieval (13th-15th century) frontier landscape: palynological analysis from Malbork Castle and hinterland, Northern Poland

Palaeoecological analysis of peat deposits from a small bog, combined with pollen analysis of sediments infilling the moat of the nearby Teutonic Order castle at Malbork, have been used to examine the ecological impact of the Crusades on the late-medieval landscape of Northern Poland. Studies of the environmental impact of the Crusades have been almost exclusively informed by written sources; this study is the first of its type to directly investigate the environmental context of Crusading as a force of ecological transformation on the late-medieval Baltic landscape. The pollen evidence from Malbork Castle and its hinterland demonstrate that the 12th/13th–15th centuries coincide with a marked transformation in vegetation and land-use, characterized by clearance of broadleaved woodland and subsequent agricultural intensification, particularly during the 14th/15th centuries. These changes are ascribed to landscape transformations associated with the Teutonic Order’s control of the landscape from the mid-13th century. Human activity identified in the pollen record prior to this is argued to reflect the activities of Pomeranian settlers in the area. This paper also discusses the broader palaeoecological evidence for medieval landscape change across Northern Poland.

Cosmopolitan Catterick? Isotopic evidence for population mobility on Rome’s Northern frontier

In order to investigate how the population diversity at major Romano-British urban centres compared to small towns and military outposts, we conducted multi-isotope (carbon, nitrogen, oxygen and strontium) analyses of bones (42 individuals) and teeth (26 individuals) of human skeletons from Cataractonium/ Roman Catterick in North Yorkshire (U.K.). The results suggest a markedly less diverse population at Catterick than at the larger towns. Significant differences are observed between burials from the town and fort area and the suburb of Bainesse to the south, and it is suggested that these reflect a shift to more localised recruitment for the Roman army in the Late Roman period. Isotope data for the ‘Bainesse Eunuch’, an unusual 4th century burial that has been interpreted as the remains of a ‘transvestite’ priest of Cybele, are not ultimately conclusive but consistent with origins in Southern Britain or areas with a similar climate abroad. This paper also presents strontium isotope data for modern vegetation samples from 17 sites in the Catterick/northern Vale of York area which contribute to a continuing effort to map the biosphere 87Sr/86Sr variation in Britain.

Frontiers and borderlands in Imperial perspectives: exploring Rome’s Egyptian frontier

Archaeological research has addressed imperial frontiers for more than a century. Romanists, in particular, have engaged in exploring frontiers from economic, militaristic, political, and (more recently) social vantages. This article suggests that we also consider the dialogue between space and social perception to understand imperial borderland developments. In addition to formulating new theoretical approaches to frontiers, this contribution represents the first comprehensive overview of both the documentary sources and the archaeological material found in Egypt's Great Oasis during the Roman period (ca. 30 B.C.E. to the sixth century C.E.). A holistic analysis of these sources reveals that Egypt's Great Oasis, which consisted of two separate but linked oases, served as a conceptual, physical, and human buffer zone for the Roman empire. This buffer zone protected the "ordered" Nile Valley inhabitants from the "chaotic" desert nomads, who lived just beyond the oases. This conclusion suggests that nomads required specific imperial frontier policies and that these policies may have been ideological as well as economic and militaristic.

Integrating spatial dependence into stochastic frontier analysis

An approach to incorporate spatial dependence into stochastic frontier analysis is developed and applied to a sample of 215 dairy farms in England and Wales. A number of alternative specifications for the spatial weight matrix are used to analyse the effect of these on the estimation of spatial dependence. Estimation is conducted using a Bayesian approach and results indicate that spatial dependence is present when explaining technical inefficiency.

Holocene settlement shifts and paleoenvironments on the Central Iranian Plateau: investigating linked systems

For thousands of years, humans have inhabited locations that are highly vulnerable to the impacts of climate change, earthquakes, and floods. In order to investigate the extent to which Holocene environmental changes may have impacted on cultural evolution, we present new geologic, geomorphic, and chronologic data from the Qazvin Plain in northwest Iran that provides a backdrop of natural environmental changes for the simultaneous cultural dynamics observed on the Central Iranian Plateau. Well-resolved archaeological data from the neighbouring settlements of Zagheh (7170—6300 yr BP), Ghabristan (6215—4950 yr BP) and Sagzabad (4050—2350 yr BP) indicate that Holocene occupation of the Hajiarab alluvial fan was interrupted by a 900 year settlement hiatus. Multiproxy climate data from nearby lakes in northwest Iran suggest a transition from arid early-Holocene conditions to more humid middle-Holocene conditions from c. 7550 to 6750 yr BP, coinciding with the settlement of Zagheh, and a peak in aridity at c. 4550 yr BP during the settlement hiatus. Palaeoseismic investigations indicate that large active fault systems in close proximity to the tell sites incurred a series of large (MW ~7.1) earthquakes with return periods of ~500—1000 years during human occupation of the tells. Mapping and optically stimulated luminescence (OSL) chronology of the alluvial sequences reveals changes in depositional style from coarse-grained unconfined sheet flow deposits to proximal channel flow and distally prograding alluvial deposits sometime after c. 8830 yr BP, possibly reflecting an increase in moisture following the early-Holocene arid phase. The coincidence of major climate changes, earthquake activity, and varying sedimentation styles with changing patterns of human occupation on the Hajiarab fan indicate links between environmental and anthropogenic systems. However, temporal coincidence does not necessitate a fundamental causative dependency.

Perceptions of informal safety nets: a case study from a South African informal settlement

The relevance and importance of informal safety nets that buffer poor households from livelihood hardships have been given little attention in South Africa’s development programmes to date. This article contributes to the understanding of informal safety nets by investigating local perceptions in a South African informal settlement. The main findings of the study are that families perform an important safety net function, but that these sources of assistance can be susceptible to social isolation. Immediate neighbours and friends also play an important safety net role, but these reciprocal-based sources of assistance may be difficult to secure. Community-wide threats can have a severe impact on people’s ability to engage in safety net transfers. Many of these difficulties stem from South Africa’s structural unemployment crisis. This factor is the greatest danger to the future of the informal safety net system in the informal settlement.