Textural and geochemical analysis of a pumice polisher with grooves from the Magdalenian site of Duruthy (Sorde, Landes, France)

Magdalenian archaeological sites often contain grooved polishers used to polish other implements (for example, Capitan and Peyrony 1928). These objects are generally made from sandstone but a few are made from pumice. Bibliographic research revealed that only four sites have yielded pumice stone polishers (fig. 1, fig. 2, tab. 1). These are the sites of Gourdan (Piette 1873), Isturitz (Passemard 1944), Aitzbitarte IV (Barandiaran 1965) and Arancou (Chauchat et al. 1999). Several polishers were found in the Duruthy rock-shelter, Sorde-L'abbaye, Landes. Most of these polishers are in sandstone (fig. 3) but one of them is different and has the appearance of pumice (fig. 4). The textural study and geochemical analysis (fig. 5, fig. 6, tab. 2) of this polisher indicate that it was made from rhyolitic pumice. The geochemical characteristics of this material indicate that it is not a product of French volcanism. The fact that all the sites where pumice polishers were found are located near the Atlantic Ocean suggests that floated pumices may have been collected along the ocean shores. Such rhyolitic pumices could have been produced during the eruption of a volcano on an island in the Atlantic Ocean. Although we have not yet identified the volcano responsible for this eruption, this remains the most likely hypothesis. In this respect, these artefacts offer a new approach to the study of the exploitation of the littoral zone by the last Palaeolithic hunters in southwest France and northern Spain

Bone sialoprotein plays a functional role in bone formation and osteoclastogenesis.

International audienceBone sialoprotein (BSP) and osteopontin (OPN) are both highly expressed in bone, but their functional specificities are unknown. OPN knockout ((-/-)) mice do not lose bone in a model of hindlimb disuse (tail suspension), showing the importance of OPN in bone remodeling. We report that BSP(-/-) mice are viable and breed normally, but their weight and size are lower than wild-type (WT) mice. Bone is undermineralized in fetuses and young adults, but not in older (>/=12 mo) BSP(-/-) mice. At 4 mo, BSP(-/-) mice display thinner cortical bones than WT, but greater trabecular bone volume with very low bone formation rate, which indicates reduced resorption, as confirmed by lower osteoclast surfaces. Although the frequency of total colonies and committed osteoblast colonies is the same, fewer mineralized colonies expressing decreased levels of osteoblast markers form in BSP(-/-) versus WT bone marrow stromal cultures. BSP(-/-) hematopoietic progenitors form fewer osteoclasts, but their resorptive activity on dentin is normal. Tail-suspended BSP(-/-) mice lose bone in hindlimbs, as expected. In conclusion, BSP deficiency impairs bone growth and mineralization, concomitant with dramatically reduced bone formation. It does not, however, prevent the bone loss resulting from loss of mechanical stimulation, a phenotype that is clearly different from OPN(-/-) mice

Vuorovaikutteisen suunnittelun haasteet ja mahdollisuudet metsätalouden vesiensuojelussa

Rapport de l'expertise scientifique collectiveLes animaux peuvent-ils éprouver des émotions, peuvent-ils penser, ont-ils une histoire de vie ? Depuis l’Antiquité, les philosophes ont proposé des réponses contrastées à ces questions. Du XIXème siècle à nos jours, la réflexion sur ce que sont les animaux s’est enrichie d’apports scientifiques : théorie de l’évolution, éthologie, neurophysiologie, sciences cognitives. Mais la conscience animale reste toujours l’objet de débats importants dans la communauté scientifique. Ainsi en 2012 un groupe de scientifiques de premier plan a éprouvé la nécessité de publier un manifeste intitulé « Déclaration de Cambridge sur la Conscience », qui énonce qu’«…une convergence de preuves indique que les animaux non humains disposent des substrats neuro-anatomiques, neurochimiques et neurophysiologiques des états conscients ainsi que la capacité d’exprimer des comportements intentionnels...».Les connaissances actuelles, dont cette expertise collective propose une synthèse, montrent que les animaux possèdent un large éventail de capacités cognitives associées à des comportements plus ou moins complexes. Les formes de conscience étudiées chez les humains supposent des capacités cognitives distinctes que l’on retrouve chez certains animaux. Peut-on en postuler que ceux-ci ont des formes de consciences équivalentes à celles de l’homme, sans être forcément identiques ?L’étude des niveaux et des contenus de la conscience chez les animaux est en passe de devenir un enjeu scientifique important en raison de la complexité du sujet et des controverses qu’il ne manquera pas de susciter. Enfin, les acquis scientifiques dans ce domaine invitent à reprendre les réflexions morales concernant les relations que les hommes entretiennent avec les animaux (et particulièrement avec les animaux domestiques

Building and ornamental use of trachyte in the center of France during antiquity: Sources and criteria of identification

International audienceThe volcanic field of Chaîne des Puys (French Massif Central) includes six trachytic volcanoes, the lavas of which were more or less extensively exploited during antiquity and medieval ages as a raw material for construction, sculpture and fabrication of sarcophagi. Recent questioning on the origin of trachytes from the famous Mercury sanctuary (2nd centuries AD) built atop Puy de Dôme volcano motivated the launch of a program devoted to establish source identification criteria for trachytic artifacts based on petrography, geochemistry and mineralogy These analyses allowed to establish a list of very strong criteria allowing to distinguish each volcano. The nature of the minerals being discriminating in most cases, a small sample size is sufficient for the diagnosis.The possibilities offered by the new classification are illustrated by a reappraisal of trachyte supplying around Augustonemetum (Clermont-Ferrand) during the Gallo-Roman period. In the course of this program, we discovered a previously unknown major quarry of trachyte

Occurrence of an unknown Atlantic eruption in the Chaîne des Puys volcanic field (Massif Central, France)

International audienceA volcanic ash layer, called MF1, was recently identified in Holocene sediments from the Gourgon and Molhiac peat bogs (Monts du Forez, French Massif Central). This ash layer consists of colorless shards with a heterogeneous trachytic to rhyolitic composition. The trace elements analyzed by Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) attest to a local origin. Radiocarbon dating of peat samples taken within and below the ash layer indicates the best age at 6339 ± 61 cal yr BP, i.e. an age contemporaneous with the volcanic activity of Montchal, Montcineyre and Pavin volcanoes from the Chaîne des Puys volcanic field. These volcanoes are characterized by basaltic and trachytic products, thus the rhyolitic composition of MF1 tephra suggests that it is likely originated from an unknown eruption. These results again confirm the interest of studying the distal volcanic ash fallouts in order to establish or specify records of past eruptions of volcanic fields. Identification of this new tephra layer also provides an additional tephrochronological marker for Eastern French Massif Central