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

Avaliação de cultivares de arroz irrigado sob irrigação por aspersão.

O objetivo do trabalho foi de avaliar a resposta de cultivares de arroz irrigado em condições de cultivo com irrigação por aspersão em terras altas.Pôster - graduação

Avaliação de cultivares de arroz irrigado em condições de cultivo de terras altas sob irrigação por aspersão.

O uso de cultivares de arroz irrigado em condições de cultivo para arroz de terras altas, no Cerrado brasileiro, com manejo de irrigação por aspersão abre perspectivas de utilização desse sistema para o processo de produção de sementes. Neste sentido o trabalho objetiva avaliar a resposta de cultivares de arroz irrigado sob irrigação por aspersão em condições de cultivo de arroz de terras altas

Snail1 controls bone mass by regulating Runx2 and VDR expression during osteoblast differentiation

Bone undergoes continuous remodelling throughout adult life, and the equilibrium between bone formation by osteoblasts and bone resorption by osteoclasts defines the final bone mass. Here we show that Snail1 regulates this balance by controlling osteoblast differentiation. Snail1 is necessary for the early steps of osteoblast development, and it must be downregulated for their final differentiation. At the molecular level, Snail1 controls bone mass by repressing the transcription of both the osteoblast differentiation factor Runx2 and the vitamin D receptor (VDR) genes in osteoblasts. Sustained activation of Snail1 in transgenic mice provokes deficient osteoblast differentiation, which, together with the loss of vitamin D signalling in the bone, also impairs osteoclastogenesis. Indeed, the mineralisation of the bone matrix is severely affected, leading to hypocalcemia-independent osteomalacia. Our data show that the impact of Snail1 activity on the osteoblast population regulates the course of bone cells differentiation and ensures normal bone remodelling