Holocene Palaeoclimates of Africa

Examination of climatic inferences based on palynological, geomorphic, sedimentological, and other proxy data reveals a coherent picture of a generally wet early Holocene and drier conditions, with a time-transgressive clinal change commencing ca, 4500 B.P. The large-scale climatic periods in Africa during the Late Quaternary were interrupted by abrupt oscillations and rapid transitions. The magnitude and direction of climatic changes show distinct regional variation. However, in the monsoon-domain areas, abrupt drought events occurred conspicuously at ca. 12,000–11,500, 8500, 7500, 4500, 4000–3700, and 2000 uncalibrated radiocarbon years B.P. Further investigations are required to gain a more precise chronology of these events, which appear to have been crucial for some of the most salient developments in Africa's prehistory.     

A 3D digital workflow for archaeological intra-site research using GIS

Across a range of archaeological projects in Northern Greece, a context-based system, which has much in common with similar stratigraphic methods applied elsewhere in the world, is in use to record the excavation process. Here, we discuss a formal data model and complete digital workflow for the documentation of this process in 3D using the prehistoric site of Paliambela Kolindros, Greece, as a case study. The entire digital process has the advantage of being implemented on a single software platform. In addition, the combination of formal ontology and custom object-oriented programming enables a suite of techniques for exploratory data analysis and stratigraphic interpretation.     

Understanding Prehistoric Lithic Raw Material Selection: Application of a Gravity Model

Provenance studies can tell us which sources of lithic raw material were used in the past, but can they tell us why? After all, many factors can have entered into a person’s choice to use one source rather than another. Those factors can be grouped into two categories, the geologic/geographic characteristics of the source itself (quality, abundance, size of pieces, etc.), and the human factors (direction of travel, time available, social restrictions, etc.). This paper demonstrates how the geologic/geographic characteristics can be quantified and calculated together to give one value, the attractiveness of the source, which can then be used in a gravity model approach to predict which sources ‘should’ have been used more than others. Deviations from the predicted pattern point to situations where the human factors were of greater or lesser importance. The values are also used to delineate geographical areas within which particular sources would be likely to be used (‘areas of influence’), which gives us a useful new way of understanding the landscape within which the prehistoric group lived.     

ANALYTICAL MODELS FOR BRICK MASONRY INFILLED R/C FRAMES UNDER LATERAL LOADING

Proposed in this paper are two analytical models for predicting the inelastic response of unreinforced brick masonry infills in reinforced concrete frames subjected to mono-tonic and reversed cyclic loading. The first model is based on the traditional diagonal strut concept, while the second one is a simple isoparametric element with shear deformation only. All the essential characteristics of the hysteretic behaviour of the panel, including strength and stiffness degradation, pinching and slippage, are explicitly taken into account. The models are implemented in a general-purpose program for the inelastic time-history analysis of structures, and are used for studying the seismic behaviour of typical multistorey frames with various arrangements of infill panels, including structures with an open ground storey. The results of the analysis are in agreement with both experimentally observed behaviour and with experience regarding seismically damaged buildings.