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961.
The effect of skeletal exposure in a marine environment is an area of taphonomy that has been little investigated at the microscopic level. Understanding the peri‐mortem and subsequent post mortem history of deposition and/or redeposition is extremely important for event reconstruction and to identify deliberate or accidental redeposition. The material used for this study comes primarily from the Mary Rose shipwreck (a marine mass fatality dated AD 1545), and forensic material recovered from marine, lacustrine and terrestrial contexts is retrospectively referenced. Work presented here outlines a definitive type of marine exposure seen in temperate shallow off‐shore and intertidal marine contexts, and illustrates how it may be differentially identified from terrestrial deposition and exposure. Furthermore, the effects of rapid deposition on skeletal remains have been documented, and results indicate that marine organism fouling activity can be fully inhibited by rapid deposition of sediment. The responsible organism itself remains unidentified, but produces tunnels which are peripheral in their distribution and maintain fixed dimensions and morphology and are here associated with marine exposure. This type of microstructural change is unique and is not found in terrestrial or freshwater contexts. The study demonstrates a taphonomic microstructural change to bone and teeth which may be identified microscopically and interpreted as evidence of marine exposure. Secondarily, the history of depositional exposure between the two main Tudor layers has provided a new level of detail concerning exposure and site formation processes. The earliest Tudor layer formed rapidly over a period of months and contained no evidence of microstructural tunnelling, whereas microstructural tunnelling was seen exclusively in the second Tudor layer, formed over a period of decades, a period during which the ship's hull collapsed and a more open marine environment dominated. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
962.
This study examines possible morphological variation in the knee joint of Homo sapiens with increasing age in ostensively healthy and non‐pathological distal femora and proximal tibiae. Throughout the lifetime of each individual, the hard tissue of the knee undergoes considerable remodelling as a response to biomechanical stresses, changes in bone microarchitecture and reduction of bone mineral content as a concomitant of ageing. The knee is also subject to greater levels of degenerative joint disease than any other joint. If death occurs whilst such diseases are in the earliest stages, initial bone changes may not be visually obvious in museum specimens. If such specimens are used for comparative analyses, it is hypothesised that changes might render it problematic if all ages are conglomerated into discrete samples. This study therefore investigates the degree to which the distal femur and proximal tibia change shape during ageing and, if changes are present, whether they are expressed similarly in males and females. It also examines whether changes are of greater magnitude than those morphological differences which might exist between populations. In an example population of African‐Americans, results indicate that there is a statistically significant difference in shape between age groups and those differences become progressively greater between the youngest and oldest adults. Results also show that although morphological variation caused by ageing is apparent, those shape differences attributable to sexual dimorphism are more powerful. When two additional populations are analysed jointly with the African‐Americans (Caucasian Americans and the European Spitalfields sample), results indicate that inter‐population shape differences are considerably greater than differences caused by increasing age. Results imply that it is justifiable to combine specimens of all ages into discrete samples for comparative purposes. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
963.
This paper reports the earliest securely dated evidence for intentional dental modification in West Africa. Human remains representing 11 individuals were recovered from the sites of Karkarichikat Nord (KN05) and Karkarichinkat Sud (KS05) in the lower Tilemsi Valley of eastern Mali. The modified anterior maxillary dentitions of four individuals were recovered from KN05. The dental modification involved the removal of the mesial and distal angles of the incisor, as well as the mesial angles of the canines. The modifications did not result from task‐specific wear or trauma, but appear instead to have been produced for aesthetic purposes. All of the filed teeth belonged to probable females, suggesting the possibility of sex‐specific cultural modification. Radiocarbon dates from the site indicate that the remains pertain to the Late Stone Age (ca. 4500–4200 BP). Dental modification has not previously been reported from this region of West Africa and our findings indicate that the practice was more widespread during prehistory. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
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969.
This study describes the archaeological investigations that have taken place at the wreck site of the English slave ship Henrietta Marie (1700) since its location in 1972. Information is provided on the methodology utilized during on-site archaeological data
recovery, and the artifacts retrieved from the wreck site are described in detail. An account of complimentary documentary
research on this wrecked slaver is also presented. Contemporary historical data gleaned from shipping lists, slaver’s logs,
seamen’s wills and other sources are utilized to place Henrietta Marie within her proper context as a vehicle involved in the notorious transatlantic slave trade. 相似文献
970.
Two‐phase flow and near‐critical phenomena are likely to enhance energy transport in high‐temperature hydrothermal systems. We present a series of two‐dimensional simulations of two‐phase flow of pure water at near‐critical conditions. The results show that at near‐critical conditions, two‐phase convection can be more efficient in transporting energy than single‐phase convection. The highest heat fluxes are attained when two‐phase heat‐pipes form near the bottom boundary, recharging the root of the upflow zone and thereby enabling the formation of broad upflow regions. When the system becomes more vapor‐dominated, it loses this ability, upflow zones become narrower and the energy efficiency drops to more moderate values. 相似文献