3-D Perturbations in Conformal Turbulence

The effects of three-dimensional perturbations in two-dimensional turbulence are investigated, through a conformal field theory approach. We compute scaling exponents for the energy spectra of enstrophy and energy cascades, in a strong coupling limit, and compare them to the values found in recent experiments. The extension of unperturbed conformal turbulence to the present situation is performed by means of a simple physical picture in which the existence of small scale random forces is closely related to deviations of the exact two-dimensional fluid motion.Comment: Discussion of intermittency improved. Figure include

Late Quaternary sea-level change and early human societies in the central and eastern Mediterranean Basin : an interdisciplinary review

This article reviews key data and debates focused on relative sea-level changes since the Last Interglacial (approximately the last 132,000 years) in the Mediterranean Basin, and their implications for past human populations. Geological and geomorphological landscape studies are critical to archaeology. Coastal regions provide a wide range of resources to the populations that inhabit them. Coastal landscapes are increasingly the focus of scholarly discussions from the earliest exploitation of littoral resources and early hominin cognition, to the inundation of the earliest permanently settled fishing villages and eventually, formative centres of urbanisation. In the Mediterranean, these would become hubs of maritime transportation that gave rise to the roots of modern seaborne trade. As such, this article represents an original review of both the geo-scientific and archaeological data that specifically relate to sea-level changes and resulting impacts on both physical and cultural landscapes from the Palaeolithic until the emergence of the Classical periods. Our review highlights that the interdisciplinary links between coastal archaeology, geomorphology and sea-level changes are important to explain environmental impacts on coastal human societies and human migration. We review geological indicators of sea level and outline how archaeological features are commonly used as proxies for measuring past sea levels, both gradual changes and catastrophic events. We argue that coastal archaeologists should, as a part of their analyses, incorporate important sea-level concepts, such as indicative meaning. The interpretation of the indicative meaning of Roman fishtanks, for example, plays a critical role in reconstructions of late Holocene Mediterranean sea levels. We identify avenues for future work, which include the consideration of glacial isostatic adjustment (GIA) in addition to coastal tectonics to explain vertical movements of coastlines, more research on Palaeolithic island colonisation, broadening of Palaeolithic studies to include materials from the entire coastal landscape and not just coastal resources, a focus on rescue of archaeological sites under threat by coastal change, and expansion of underwater archaeological explorations in combination with submarine geomorphology. This article presents a collaborative synthesis of data, some of which have been collected and analysed by the authors, as the MEDFLOOD (MEDiterranean sea-level change and projection for future FLOODing) community, and highlights key sites, data, concepts and ongoing debates

4200 New Shell Mound Sites in the Southern Red Sea

This article presents evidence for over 4200 prehistoric shell midden sites distributed on opposite sides of the southern Red Sea. These sites were primarily discovered using survey methods and site location models developed for locating shell midden sites on the Farasan Islands, where over 3000 have been found during previous research. These sites have been extensively excavated in the field and dated. Combining predictive models with remote sensing, an additional 1200 sites have been detected on the opposite side of the Red Sea, centred on the Dahlak Islands in Eritrea. Before these discoveries on the Farasan and Dahlak Archipelagos, the number of published prehistoric shell midden sites in the southern Red Sea was less than twenty. Combined, these sites represent a significant addition to the prehistoric coastal archaeology of the region. These new shell midden sites, and their apparent similarities on the two opposing coastlines, may indicate evidence of cultural contacts across the Red Sea during the Holocene Red Sea

A large handaxe from Wadi Dabsa and early hominin adaptations within the Arabian Peninsula

The role played by the Arabian Peninsula in hominin dispersals out of Africa has long been debated. The DISPERSE Project has focused on south-western Arabia as a possible centre of hominin settlement and a primary stepping-stone for such dispersals. This work has led to the recent discovery, at Wadi Dabsa, of an exceptional assemblage of over 1000 lithic artefacts, including the first known giant handaxe from the Arabian Peninsula. The site and its associated artefacts provide important new evidence for hominin dispersals out of Africa, and give further insight into the giant handaxe phenomenon present within the Acheulean stone tool industry