High dynamic range imaging for archaeological recording

This paper notes the adoption of digital photography as a primary recording means within archaeology, and reviews some issues and problems that this presents. Particular attention is given to the problems of recording high-contrast scenes in archaeology and High Dynamic Range imaging using multiple exposures is suggested as a means of providing an archive of high-contrast scenes that can later be tone-mapped to provide a variety of visualisations. Exposure fusion is also considered, although it is noted that this has some disadvantages. Three case studies are then presented (1) a very high contrast photograph taken from within a rock-cut tomb at Cala Morell, Menorca (2) an archaeological test pitting exercise requiring rapid acquisition of photographic records in challenging circumstances and (3) legacy material consisting of three differently exposed colour positive (slide) photographs of the same scene. In each case, HDR methods are shown to significantly aid the generation of a high quality illustrative record photograph, and it is concluded that HDR imaging could serve an effective role in archaeological photographic recording, although there remain problems of archiving and distributing HDR radiance map data

Simultaneous optical polarimetry and X-ray observations of the magnetic CV CP Tuc (AX J2315--592)

CP Tuc (AX J2315--592) shows a dip in X-rays which lasts for approximately half the binary orbit and is deeper in soft X-rays compared with hard X-rays. It has been proposed that this dip is due to the accretion stream obscuring the accretion region from view. If CP Tuc was a polar, as has been suggested, then the length of such a dip would make it unique amongst polars since in those polars in which a dip is seen in hard X-rays the dip lasts for only 0.1 of the orbit. We present optical polarimetry and RXTE observations of CP Tuc which show circular polarisation levels of ~10 per cent and find evidence for only one photometric period. These data confirm CP Tuc as a polar. Our modelling of the polarisation data imply that the X-ray dip is due to the bulk of the primary accretion region being self-eclipsed by the white dwarf. The energy dependence of the dip is due to a combination of this self-eclipse and also the presence of an X-ray temperature gradient over the primary accretion region.Comment: 6 pages, accepted for publication in MNRA

Strong XUV irradiation of the Earth-sized exoplanets orbiting the ultracool dwarf TRAPPIST-1

We present an XMM-Newton X-ray observation of TRAPPIST-1, which is an ultracool dwarf star recently discovered to host three transiting and temperate Earth-sized planets. We find the star is a relatively strong and variable coronal X-ray source with an X-ray luminosity similar to that of the quiet Sun, despite its much lower bolometric luminosity. We find L_x/L_bol=2-4x10^-4, with the total XUV emission in the range L_xuv/L_bol=6-9x10^-4, and XUV irradiation of the planets that is many times stronger than experienced by the present-day Earth. Using a simple energy-limited model we show that the relatively close-in Earth-sized planets, which span the classical habitable zone of the star, are subject to sufficient X-ray and EUV irradiation to significantly alter their primary and any secondary atmospheres. Understanding whether this high-energy irradiation makes the planets more or less habitable is a complex question, but our measured fluxes will be an important input to the necessary models of atmospheric evolution.Comment: 5 pages, published as a letter in MNRAS (accepted 16 September 2016

Recent investigations of the megalithic landscapes of Seville province, Andalusia: Dolmen de Palacio III

This paper describes the results of the fieldwork stage (2000-2002) of a project dealing with the megalithic phenomenon in Almadén de la Plata (Sevilla, Andalusia, Spain), carried out jointly by the universities of Seville and Southampton. On the one hand, this project aims to understand the spatial and landscape dimensions of the megalithic monuments of this region, where the density and diversity of such monuments is very high. This has involved systematic surface survey of a number of designated areas in order to provide the empirical basis from which to understand spatial distributions relationships between the monuments themselves, between the monuments and settlement areas and between monuments and landscape features). On the other hand, this project is looking at aspects of the internal organisation of megalithic burials in the area. Thus excavations carried out at the site of Dolmen de Palacio III have permitted the retrieval and recording of an almost completely intact Copper Age tholos tomb, as well as providing extremely useful information about patterns of re-use of the monument between the Neolithic and the Iron Age

Investigating the suitability of carbon nanotube reinforced polymer in transcatheter valve applications

The current delivery size of transcatheter aortic valves, limited by the thickness of their pericardial leaflets, correlates with a high prevalence of major vascular complications. Polyurethane valves can be developed to a fraction of the thickness of pericardial valves through the addition of carbon nanotubes to reinforce their leaflets. This study investigates the suitability of a novel carbon nanotube reinforced leaflet to reduce the delivery profile of transcatheter aortic valves. Carbon nanotube polyurethane composites were developed with thicknesses of 50 μm and their mechanical properties were determined in relation to various environmental effects. The composites demonstrated improvements to the material stiffness, particularly at increasing strain rates compared to the neat polymer. However, increasing nanotube concentrations significantly decreased the fatigue life of the composites. Key findings highlighted a potential for carbon nanotube reinforcement in valve replacement which experience very high strain rates during the cardiac cycle. Further testing is needed to achieve a strong nanotube-matrix interface which will prolong the cyclic fatigue life and further strengthen tensile properties. Testing on the durability and haemocompatibility of these composite heart valves are ongoing

Ivory craftsmanship, trade and social significance in the southern Iberian Copper Age: the evidence from the PP4? Montelirio sector of Valencina de la Concepción (Seville, Spain)

Because of its great potential to provide data on contacts and overseas trade, ivory has aroused a great deal of interest since the very start of research into Iberian late prehistory. Research recently undertaken by the German Archaeological Institute in Madrid in collaboration with a number of other institutions has provided valuable contributions to the study of ivory in the Iberian Copper Age and Early Bronze Age. One of the archaeological sites that is contributing the most data for analysing ivory from the Copper Age in southern Iberia is Valencina de la Concepcion (Seville), which is currently the focus of several debates on the development of social complexity. This article contributes to this line of research by providing new, unpublished evidence and by examining the significance of ivory craftsmanship in commercial, social, and ideological terms. It also assesses in greater detail the prominent part played by luxury ivory items as an expression of social status and power.<br/

Calculation of high-order virial coefficients for the square-well potential

Accurate virial coefficients BN(λ,ε) (where ε is the well depth) for the three-dimensional square-well and square-step potentials are calculated for orders N = 5–9 and well widths λ = 1.1−2.0 using a very fast recursive method. The efficiency of the algorithm is enhanced significantly by exploiting permutation symmetry and by storing integrands for reuse during the calculation. For N = 9 the storage requirements become sufficiently large that a parallel algorithm is developed. The methodology is general and is applicable to other discrete potentials. The computed coefficients are precise even near the critical temperature, and thus open up possibilities for analysis of criticality of the system, which is currently not accessible by any other means

El asentamiento de la Edad del Cobre de Valencina de la Concepción (Sevilla). Demografía, metalurgia y organización espacial

This paper presents the results obtained from a review of the archaeological record available for the prehistoric site of Valencina de la Concepción (Seville, Spain), one of the most important settlements of SW Iberia in the 3rd and 2nd millennia BC. Two main variables, namely demography and metallurgical production, are examined in the light of both conventional and spatial statistical methods (with particular emphasis on significance testing) with the aim of assessing the wider issue of social complexity. Among the various conclusions emerging from this empirical study, two stand out. Firstly, neither the correlation between the total extension of the settlement and the complexity of its internal organisation, nor the spatial delimitation between domestic/productive and funerary practices is as straightforward as previously claimed. Secondly, no simple, clear-cut statistical patterns are found in the spatial distribution of human remains or metal objects. These conclusions provide the basis for a critique of currently held interpretations of Valencina de la Concepción as the political centre of an early state extending across the lower Guadalquivir valleyEn este trabajo se presentan los resultados obtenidos en una revisión del registro arqueológico disponible del sitio prehistórico de Valencina de la Concepción (Sevilla, España), uno de los asentamientos más importantes del Suroeste de la Península Ibérica durante los milenios III y II ANE. A la luz de métodos estadísticos convencionales y espaciales (con particular énfasis en las pruebas de significación) se examinan dos variables principales, la demografía y la metalurgia, con el objeto de valorar la más amplia cuestión de la complejidad social. De las principales conclusiones obtenidas en este estudio destacan dos. En primer lugar, ni la correlación entre la extensión total del asentamiento y la complejidad de su organización interna, ni la delimitación espacial entre las prácticas doméstico-productivas y funerarias es tan simple como se ha propuesto anteriormente. En segundo lugar, no existen pautas estadísticas definidas o evidentes en la distribución de los depósitos de restos humanos y objetos metálicos. Estas conclusiones proporcionan la base para una crítica de interpretaciones recientemente propuestas que presentan a Valencina de la Concepción como el centro político de un estado temprano que se extendía por el valle del bajo Guadalquivi

La Edad del Cobre en las tierras de Antequera (Málaga): introducción a los patrones de asentamiento y dinámicas sociales

Antequera (Málaga) is home to one of the most important Neolithic and Copper Age megalithic landscapes in Europe, as proven by its recent declaration as a World Heritage Site by UNESCO in July 15th 2016. This declaration highlights the need to push ahead in the research of the Neolithic and Copper Age periods, when the megalithic phenomenon developed and the three large Antequera megaliths, Menga, Viera and El Romeral, were built. In this paper, stemming from an on-going research project, we present a synthesis of the evidence available for the study of the Copper Age settlement patterns and social dynamics in the Lands of Antequera. Departing from a comprehensive review of the existing literature an assessment is made of the settlement patterns, subsistence economy, exploitation and exchange of abiotic resources, monumentality and burial practices of this time period. The aim is to formulate a preliminary framework of analysis of the cultural and social context in which the construction of El Romeral, the largest tholos monument known in Iberia, took place.Antequera (Málaga) alberga uno de los más importantes paisajes megalíticos del Neolítico y la Edad del Cobre en Europa, como lo demuestra su reciente declaración como Patrimonio de la Humanidad por la UNESCO el 15 de julio de 2016. Esta declaración pone el foco en la necesidad de avanzar en la investigación de los periodos Neolítico y Edad del Cobre, en los que se produce el apogeo del fenómeno megalítico y en cuyo contexto se construyen los tres grandes megalitos antequeranos, Menga, Viera y El Romeral. En este artículo, que deriva de un proyecto de investigación actualmente en curso, se presenta una síntesis de los datos disponibles para el conocimiento de las pautas de asentamiento y las dinámicas sociales de la Edad del Cobre en Tierras de Antequera. Partiendo de una exhaustiva síntesis de la literatura existente, se realiza un ensayo de valoración de los patrones de asentamiento, la economía subsistencial, la explotación e intercambio de recursos abióticos, la monumentalidad y las prácticas funerarias en este periodo. Con ello se persigue formular un marco preliminar de análisis del contexto cultural y social en el que se dio la construcción de El Romeral, el mayor “tholos” conocido en Iberia