A newly discovered antler flint-knapping hammer and the question of their rarity in the Palaeolithic archaeological record: Reality or bias?

The use of soft (bone, antler, tooth and wood) hammers and retouchers is a key innovation in early stone tool technology, first appearing in the archaeological record with Lower Palaeolithic handaxe industries (e.g. Boxgrove, UK ~ 500 kya). Although organic knapping tools were undoubtedly a component of early human toolkits and are essential, for example, for the manufacture of finely-flaked handaxes, Mousterian scrapers and Upper Palaeolithic blades tools, such archaeological finds are exceptionally rare. In this study, we present qualitative and quantitative analyses (focus variation optical microscope, scanning electron microscope, micro-CT scanning and energy dispersive X-ray spectroscopy), to characterise use-damage on an antler base from Laugerie-Haute West (France). This specimen was originally identified as a waste-product from splinter manufacture, and the use-damage appears to have been missed. The new analysis shows that prior to being used as a flint-knapping percussor, the red deer antler had been further modified to reduce the length of its beam and to remove the tines. Although minimally used, characteristic use-damage includes attrition (pits and scores), compression of the antler matrix and flint chips embedded within some of the percussion features on the base of the burr. An AMS radiocarbon date of 12385 ± 55 BP (12647 ± 335 BC calibrated) confirms a Magdelanian context for the hammer. The fact that the Laugerie Haute knapping hammer went unrecognised in a well-studied and accessible collection for almost 200 years since its discovery, suggests that antler hammers may be more common than generally assumed. Only further re-examination of prehistoric antlers in museum collections will confirm whether the apparent rarity of antler hammers during the Lower and Middle Palaeolithic is real phenomenon or the result of analytical biases

Sistema sulco/camalhão para culturas em rotação ao arroz em áreas de várzeas do Rio Grande do Sul.

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Superlattice properties of carbon nanotubes in a transverse electric field

Electron motion in a (n,1) carbon nanotube is shown to correspond to a de Broglie wave propagating along a helical line on the nanotube wall. This helical motion leads to periodicity of the electron potential energy in the presence of an electric field normal to the nanotube axis. The period of this potential is proportional to the nanotube radius and is greater than the interatomic distance in the nanotube. As a result, the behavior of an electron in a (n,1) nanotube subject to a transverse electric field is similar to that in a semiconductor superlattice. In particular, Bragg scattering of electrons from the long-range periodic potential results in the opening of gaps in the energy spectrum of the nanotube. Modification of the bandstructure is shown to be significant for experimentally attainable electric fields, which raises the possibility of applying this effect to novel nanoelectronic devices.Comment: 7 pages, 3 figure

Drenagem superficial para cultivos rotacionados em solos de várzea.

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Excavations at the Lower Palaeolithic Site at Elveden, Suffolk

The Lower Palaeolithic site at Elveden, Suffolk, was the subject of new excavations from 1995–1999. Excavations around the edge and in the centre of the former clay-pit revealed sediments infilling a lake basin that had formed in Lowestoft till, overlying Chalk, the till being attributed to the Anglian glaciation (MIS 12). The lake sediments contain pollen that can be assigned to pollen zones HoI and HoIIa of the early Hoxnian (MIS 11). Overlying grey clays contain ostracods, molluscs, vertebrates, and carbonate concretions. Together they are indicative of a fluvial environment in a temperate climate. AAR ratios (amino acid racemisation) on the molluscs also suggest correlation with MIS 11. Further indications of a fluvial context are indicated by thin spreads of lag gravel along opposite sides of the clay-pit, marking the edges of a channel. The gravel forms the raw material for the human industries which consist of handaxes, flake tools, flakes, and cores. Further artefacts are found in the overlying black clay, which is interpreted as a palaeosol that formed with the silting-up of the channel. The basin was further infilled with colluvial ‘brickearths’, which also contain artefacts that are probably derived from the underlying gravel. Further evidence of soil formation was identified in the ‘brickearth’. Coversands with periglacial involutions overlie the ‘brickearth’ at the top of the sequence. These probably formed in the last cold stage, the Devensian

Effects of precompetition state anxiety interventions on performance time and accuracy among amateur soccer players: Revisiting the matching hypothesis

In this study, we tested the matching ypothesis, which contends that administration of a cognitive or somatic anxiety intervention should be matched to a participant's dominant anxiety response. Sixty-one male soccer players (mean age 31.6 years, s=6.3) were assigned to one of four groups based on their responses to the Competitive State Anxiety Inventory-2, which was modified to include a directional scale. Interventions were randomly administered in a counterbalanced order 10 min before each performance trial on a soccer skill test. The dominantly cognitive anxious group (n=17), the dominantly somatic anxious group (n=17), and the non-anxious control intervention group (n=14) completed a baseline performance trial. The second and third trials were completed with random administration of brief cognitive and somatic interventions. The non-anxious control group (n=13) completed three trials with no intervention. A mixed-model, GroupTreatment multivariate analysis of variance indicated significant (P0.05), or performance time or accuracy (P>0.05). The present findings do not provide support for the matching hypothesis for state anxiety intensity and direction, or for performance

Rice and Barnyardgrass: Water Stress and Initial Establishment.

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