Spin-density wave in Cr: nesting versus low-lying thermal excitations

It is well known that present versions of density functional theory do not predict the experimentally observed spin-density wave state to be the ground state of Cr. Recently, a so-called "nodon model" has been proposed as an alternative way to reconcile theory and experiment: the ground state of Cr is truly antiferromagnetic, and the spin-density wave appears due to low-lying thermal excitations ("nodons"). We examine in this paper whether the postulated properties of these nodons are reproduced by ab initio calculations

Wear traces of basalt tools - an experimental case for archaeological interpretation (BATEX): a new project on micro-wear studies of basalt tools

editorial reviewe

There is more to life than subsistence: use-wear and residue analyses on pre-Still Bay stone tools at Sibudu

peer reviewe

Tool use and hafting in the Middle Palaeolithic of North Africa: preliminary results of an on-going use-wear analysis on the Mousterian/Aterian assemblages of Ifri n’Ammar (Morocco)

peer reviewedThe rock shelter of Ifri n’Ammar has a remarkable stratigraphy with alternating Mousterian and Aterian occupations within more than 6 meters of sediments dated from MIS 6 to 5a. The stratigraphy attributed to the Middle-Palaeolithic is divided in two units, separated by a calcareous crust, where upper and lower Aterian occupations can be identified. Previous studies have characterised Aterian and Mousterian cultures on a typological and technological basis. Functional data on lithic industries from the Middle Palaeolithic in northern Africa is at present very scarce and detailed studies of the production, hafting and use of tools, particularly tanged pieces, have not yet been conducted. Preliminary results of an on-going use-wear analysis of Middle Palaeolithic stone tools from the site of Ifri n’Ammar will be presented. Both low and high magnifications are combined for examining the macro- and microscopic wear traces on the stone tools. The interpretation of the archaeological material is based on comparisons with an experimental reference collection. The long-term goal of the study is to understand how stone tools were used, whether hafted stone tools existed at the site and how these functional parameters compare to the typo-technological characteristics of the different assemblages and how they may have influenced assemblage variability.Marokko: Ur- und Frühgeschichte des östlichen Ri

Why did hunting weapon design change at Abri Pataud? Lithic use-wear data on armature use and hafting around 24,000–22,000 BP

Projectile technology is commonly viewed as a significant contributor to past human subsistence and, consequently, to our evolution. Due to the allegedly central role of projectile weapons in the food-getting strategies of Upper Palaeolithic people, typo-technological changes in the European lithic record have often been linked to supposed developments in hunting weaponry. Yet, relatively little reliable functional data is currently available that would aid the detailed reconstruction of past weapon designs. In this paper, we take a use-wear approach to the backed tool assemblages from the Recent and Final Gravettian layers (Levels 3 and 2) of Abri Pataud (Dordogne, France). Our use of strict projectile identification criteria relying on combinations of low and high magnification features and our critical view of the overlap between production and use-related fractures permitted us to confidently identify a large number of used armatures in both collections. By isolating lithic projectiles with the strongest evidence of impact and by recording wear attributes on them in detail, we could establish that the hunting equipment used during the Level 3 occupations involved both lithic weapon tips and composite points armed with lithic inserts. By contrast, the Level 2 assemblage reflects a heavy reliance on composite points in hunting reindeer and other game. Instead of an entirely new weapon design, the Level 2 collection therefore marks a shift in weapon preferences. Using recent faunal data, we discuss the significance of the observed diachronic change from the point of view of prey choice, seasonality, and social organisation of hunting activities. Our analysis shows that to understand their behavioural significance, typo-technological changes in the lithic record must be viewed in the light of functional data and detailed contextual information

The worked bone industry and intrusive fauna associated with the prehistoric cave burials of Abri des Autours (Belgium)

peer reviewe

Functioneel onderzoek van Laat-Paleolithische en Vroeg-Mesolithische sites in Vlaanderen.

Lithische artefacten zijn de meest voorkomende resten die worden teruggevonden op steentijdsites en op basis van een gedetailleerde studie van deze artefacten kan gereconstrueerd worden wat er precies op deze plaats in het landschap gebeurde. Veelal gebeurt dit via een typologische classificatie van het materiaal, vaak gecombineerd met een technologische studie en al dan niet met de integratie van studies van het ruw materiaal zelf. Deze methodes exploiteren echter slechts een deel van de beschikbare gegevens en geven geen inzicht in welke artefacten werkelijk gebruikt werden, waarvoor ze gebruikt werden en hoe. Een gebruikssporenonderzoek is één van de enige manieren om inzicht te verkrijgen in de organische component van de prehistorische technologie, die veelal niet bewaard is gebleven. Een dergelijke analyse laat ook toe om te bepalen wat de functie van een site was (bv. basiskamp, jachtkamp, productie-site) en te onderzoeken wat het verband is met de locatie in het landschap of met andere sites in de omgeving (voor eenzelfde tijdsperiode). Tot op heden is de functie van de meeste Paleo/Mesolithische sites nog onbekend en is het vaak moeilijk om in te schatten hoe concentraties moeten geïnterpreteerd worden. De mogelijkheden hiervan worden natuurlijk mee bepaald door de gebruikte opgravingsstrategie. Op dit moment is de regel dat het opgegraven sediment moet gezeefd worden, maar de exacte zeefmethode heeft een grote invloed op de bewaring van de gebruikssporen en de eventueel aangehechte residus. Er was tot op heden nog geen systematische studie gebeurd over de invloed van de gebruikte zeeftechniek op de bewaring van functionele resten

Non-destructive identification of prehistoric adhesives by HS-GCxGC-TOFMS: preliminary study

Identification of prehistoric adhesives on stone tools is valuable as it might reveal something about tool use. Currently, prehistoric glues are chemically analysed by gas chromatography coupled to mass spectrometer (GC-MS) which requires extraction and derivatization of the residues1. This is a major drawback as it is destructive for the glue and often, the required amount is not present. Moreover, the adhesives cover a wide range of materials (e.g., resin, animal glue, gum). Therefore, sensitive, universal, and non-destructive identification methods are needed. Headspace solid phase micro-extraction (HS-SPME) in combination with GC-MS and with comprehensive GC-time-of-flight mass spectrometer (HS-SPME-GCxGC-TOFMS) has been proposed2,3. But the sensitivity remains a problem. In this study dynamic headspace (DHS)-GCxGC-TOFMS is tested on several adhesives and compared with HS-SPME-GCxGC-TOFMS. The DHS method is optimized and validated via design of experiment on pine resin and hide glue. 1. D. Cnuts, K. A. Perrault, P. H. Stefanuto, L. M. Dubois, J. F. Focant, and V. Rots, Archaeometry, 2018, 60, 1361. 2. K. A. Perrault, L. M. Dubois, D. Cnuts, V. Rots, J.-F. Focant, and P.-H. Stefanuto, Separation Science Plus, 2018, 1, 726. 3. M. Regert, V. Alexandre, N. Thomas, and A. Lattuati-Derieux, Journal of Chromatography A, 2006, 1101, 245

Gone with the wind? Evaluating the functional potential of a federmessergruppen assemblage from the eroded dune landscape of Lommel Maatheide

peer reviewe