Tautavel – Grotte Tissia/Atrapa-Conills

La découverte en surface, dans la cavité Atrapa-Conills, d’une pointe foliacée en silex et de quelques dents et phalanges humaines, a conduit à mener un sondage dans les déblais présents en amont de la cavité. Trois tranchées ont été creusées sur une surface d’environ 3,3 m2, deux longitudinales et une transversale. Elles nous ont permis de mettre en lien le déblai avec une phase de vidage anthropique de la cavité datant des années 1960 et effectuée par un groupe de spéléologues. De ce vidage..

The First 3D Simulations of Carbon Burning in a Massive Star

We present the first detailed three-dimensional hydrodynamic implicit large eddy simulations of turbulent convection for carbon burning. The simulations start with an initial radial profile mapped from a carbon burning shell within a 15 solar mass stellar evolution model. We considered 4 resolutions from 128^3 to 1024^3 zones. These simulations confirm that convective boundary mixing (CBM) occurs via turbulent entrainment as in the case of oxygen burning. The expansion of the boundary into the surrounding stable region and the entrainment rate are smaller at the bottom boundary because it is stiffer than the upper boundary. The results of this and similar studies call for improved CBM prescriptions in 1D stellar evolution models.Comment: 5 pages, 3 figures. Published in IAUS 329 on 28/07/1

Linking 1D Evolutionary to 3D Hydrodynamical Simulations of Massive Stars

Stellar evolution models of massive stars are important for many areas of astrophysics, for example nucleosynthesis yields, supernova progenitor models and understanding physics under extreme conditions. Turbulence occurs in stars primarily due to nuclear burning at different mass coordinates within the star. The understanding and correct treatment of turbulence and turbulent mixing at convective boundaries in stellar models has been studied for decades but still lacks a definitive solution. This paper presents initial results of a study on convective boundary mixing (CBM) in massive stars. The 'stiffness' of a convective boundary can be quantified using the bulk Richardson number ($\textrm{Ri}_B$), the ratio of the potential energy for restoration of the boundary to the kinetic energy of turbulent eddies. A 'stiff' boundary ($\textrm{Ri}_B \sim 10^4$) will suppress CBM, whereas in the opposite case a 'soft' boundary ($\textrm{Ri}_B \sim 10$) will be more susceptible to CBM. One of the key results obtained so far is that lower convective boundaries (closer to the centre) of nuclear burning shells are 'stiffer' than the corresponding upper boundaries, implying limited CBM at lower shell boundaries. This is in agreement with 3D hydrodynamic simulations carried out by Meakin and Arnett [The Astrophysical Journal 667:448-475, 2007]. This result also has implications for new CBM prescriptions in massive stars as well as for nuclear burning flame front propagation in Super-Asymptotic Giant Branch stars and also the onset of novae.Comment: Accepted for publication (12/12/15) in the Physica Scripta focus issue on Turbulent Mixing and Beyon

Linking 1D Stellar Evolution to 3D Hydrodynamical Simulations

In this contribution we present initial results of a study on convective boundary mixing (CBM) in massive stellar models using the GENEVA stellar evolution code. Before undertaking costly 3D hydrodynamic simulations, it is important to study the general properties of convective boundaries, such as the: composition jump; pressure gradient; and `stiffness'. Models for a 15Mo star were computed. We found that for convective shells above the core, the lower (in radius or mass) boundaries are `stiffer' according to the bulk Richardson number than the relative upper (Schwarzschild) boundaries. Thus, we expect reduced CBM at the lower boundaries in comparison to the upper. This has implications on flame front propagation and the onset of novae.Comment: 2 pages, 1 figure. To appear in proceedings of the IAU Symposium 307: New Windows on Massive Stars: Asteroseismology, Interferometry and Spectropolarimetr

Traumatic brain injury in England and Wales: prospective audit of epidemiology, complications and standardised mortality.

OBJECTIVES: To provide a comprehensive assessment of the management of traumatic brain injury (TBI) relating to epidemiology, complications and standardised mortality across specialist units. DESIGN: The Trauma Audit and Research Network collects data prospectively on patients suffering trauma across England and Wales. We analysed all data collected on patients with TBI between April 2014 and June 2015. SETTING: Data were collected on patients presenting to emergency departments across 187 hospitals including 26 with specialist neurosurgical services, incorporating factors previously identified in the Ps14 multivariate logistic regression (Ps14n) model multivariate TBI outcome prediction model. The frequency and timing of secondary transfer to neurosurgical centres was assessed. RESULTS: We identified 15 820 patients with TBI presenting to neurosurgical centres directly (6258), transferred from a district hospital to a neurosurgical centre (3682) and remaining in a district general hospital (5880). The commonest mechanisms of injury were falls in the elderly and road traffic collisions in the young, which were more likely to present in coma. In severe TBI (Glasgow Coma Score (GCS) ≤8), the median time from admission to imaging with CT scan is 0.5 hours. Median time to craniotomy from admission is 2.6 hours and median time to intracranial pressure monitoring is 3 hours. The most frequently documented complication of severe TBI is bronchopneumonia in 5% of patients. Risk-adjusted W scores derived from the Ps14n model indicate that no neurosurgical unit fell outside the 3 SD limits on a funnel plot. CONCLUSIONS: We provide the first comprehensive report of the management of TBI in England and Wales, including data from all neurosurgical units. These data provide transparency and suggests equity of access to high-quality TBI management provided in England and Wales.AH is supported by the University of Cambridge, UK and Medical Research Council/Royal College of Surgeons of England Clinical Research Training Fellowship (Grant no. G0802251). P.J.H. is supported by National Institute for Health Research Professorship, Academy of Medical Sciences/Health Foundation Senior Surgical Scientist Fellowship and the National Institute for Health Research Biomedical Research Centre, Cambridge.This is the final version of the article. It first appeared from the BMJ Publishing Group. via https://doi.org/10.1136/bmjopen-2016- 01219

Flint vs. Limestone – A comparative analysis on the development of macro-wear traces: Implications for the analysis of ancient lithic toolkits

Especially for the Lower Palaeolithic, traceological analysis is very difficult to carry out due to bad preservation and the diversity of raw materials used for tool production. Due to the problem of preservation, focuses the functional analysis on the observation of macro-wear appears to be a good solution to the challenge of obtaining functional data. We propose thus to present the results of a large experiment (up to 300 experimental tools), conducted with limestone and flint flakes. Controlled parameters were disposed to provide replicative criteria for comparison. Three movements were performed systematically (longitudinal action, and transversal action both unidirectional and bidirectional), across two durations. In the first stage, actions were realised on the same worked material: dry wood calibrated. Each raw material for each action was represented by 48 experimental tools. In the second stage (63 experimental tools), the same actions were realised on different worked materials such as fresh wood, skin, bone, meat, and others. The macro-wear traces produced (mainly micro-flakes) were described relative to their position on the edge and their morphology. The comparison between the two raw materials was made using a statistical approach. The results were discussed under the influence of different parameters: morphology of the cutting edge, duration of use and edge angle of the active part. These results confirm firstly that macro-wear is reliable in determining the tool movement. Moreover, as assessed by the chosen criteria, only a few differences exist in the macro-wear development between flint and limestone. Finally, we conclude that the micro-flakes provide relevant information and should be used more frequently for functional analysis of ancient and badly preserved material.Especially for the Lower Palaeolithic, traceological analysis is very difficult to carry out due to bad preservation and the diversity of raw materials used for tool production. Due to the problem of preservation, focuses the functional analysis on the observation of macro-wear appears to be a good solution to the challenge of obtaining functional data. We propose thus to present the results of a large experiment (up to 300 experimental tools), conducted with limestone and flint flakes. Controlled parameters were disposed to provide replicative criteria for comparison. Three movements were performed systematically (longitudinal action, and transversal action both unidirectional and bidirectional), across two durations. In the first stage, actions were realised on the same worked material: dry wood calibrated. Each raw material for each action was represented by 48 experimental tools. In the second stage (63 experimental tools), the same actions were realised on different worked materials such as fresh wood, skin, bone, meat, and others. The macro-wear traces produced (mainly micro-flakes) were described relative to their position on the edge and their morphology. The comparison between the two raw materials was made using a statistical approach. The results were discussed under the influence of different parameters: morphology of the cutting edge, duration of use and edge angle of the active part. These results confirm firstly that macro-wear is reliable in determining the tool movement. Moreover, as assessed by the chosen criteria, only a few differences exist in the macro-wear development between flint and limestone. Finally, we conclude that the micro-flakes provide relevant information and should be used more frequently for functional analysis of ancient and badly preserved material

Cyril Viallet (2016) — Potentiel fonctionnel des outils bifaciaux au Pléistocène moyen en contexte méditerranéen. Analyse de la structure et des macro-traces des outils bifaciaux de la Caune de l’Arago, Terra Amata, Orgnac 3 et du Lazaret, Thèse soutenue le 24 octobre 2016 à l’université de Perpignan « Via-Domitia »

Viallet Cyril. Cyril Viallet (2016) — Potentiel fonctionnel des outils bifaciaux au Pléistocène moyen en contexte méditerranéen. Analyse de la structure et des macro-traces des outils bifaciaux de la Caune de l’Arago, Terra Amata, Orgnac 3 et du Lazaret, Thèse soutenue le 24 octobre 2016 à l’université de Perpignan « Via-Domitia ». In: Bulletin de la Société préhistorique française, tome 114, n°2, 2017. pp. 384-386

Functionnal potential of bifacial tools in the middle pleistocene of the mediterranean area. Structural and use-wear analysis of bifacial series of Caune de l'Arago, Terra Amata, Orgnac and Lazaret Cave

Les différentes et nombreuses études menées sur le biface depuis le XIXème siècle, révèlent une multiplicité de fonctions potentielles, donnant l’image d’un outil polyfonctionnel. Néanmoins, cette vision est biaisée et découle de l’absence de corrélation entre les données issues des analyses fonctionnelles et la classification typologique en vigueur. Ainsi l’objectif de ce travail est de constituer des groupes d’outils bifaciaux aux potentiels fonctionnels communs et de les rattacher, quand cela est possible, à un mode d’action spécifique. Pour cela, ce travail se propose de corréler les données productionnelles et fonctionnelles par le biais d’une analyse structurelle, expérimentale et tracéologique. Cette dernière a été effectuée aux dépens de 5 séries de bifaces provenant de 4 sites du Sud-Est de la France, datés du Pléistocène moyen. Les résultats obtenus permettent de mettre en évidence neuf groupes de bifaces avec des potentialités fonctionnelles spécifiques. Parmi ces groupes, trois sont corrélés à des fonctionnements eux-mêmes particuliers. Ainsi, pour les sites étudiés, le terme de biface recouvre a minima trois types d’outils : des outils de coupes rentrantes caractérisés par un tranchant d’angle aigu sur un bord en association avec la pointe ; des outils de coupe en percussion lancée caractérisés par un tranchant transversal sur un support avec une base corticale épaisse ; et des outils portant des traces de percussion sur une pointe robuste associée à une base épaisse et corticale, potentiellement destinés à fouir/creuser. Il apparaît ainsi que, dans le Sud-Est de la France au Pléistocène moyen, le biface n’est pas un outil polyfonctionnel. Le terme recouvre ici plusieurs groupes d’outils bifaciaux aux potentialités fonctionnelles diverses. Deux fonctionnements principaux - translation longitudinale et percussion lancée indirecte - sont associés à des outils bifaciaux présentant des morphologies spécifiques. Il est possible d’observer un usage du façonnage bifacial différent en fonction des gisements. Les différents outils bifaciaux ne sont pas tous représentés de la même manière, reflétant des contraintes extrinsèques ou intrinsèques et ajoutant de la variabilité à la définition de l’Acheuléen.Since the XIX century dinstinct and numerous studies on bifaces reveal a multiplicity of potential function, giving the impression of a multifunctional tool. However this vision is biased and come from the absence of correlation between data from functional analyses and data from typological classification. Thus the objective of this work is to compose bifacial tool group depending from them potential function and when it’s possible to link them to a specific action.For this purpose, this works intend to correlate productional and functional data by structural, experimental and traceologic analyses. The latter has been done on 5 biface serie from 4 sites in the South-East France, dated from the Middle Pleistocene.Achieved results highlight nine biface groups with specific functional potentiality. Among these groups, three are correlated with particular function. Thus, for the site studied, the term biface cover a least three tools type: “coupe rentrante” tools characterize by an acute angle edge on a board associated with the tip; cutting tools in pitched percussion characterize by a transversal edge on a support with a thick cortical base; and tools bearing percussion marks on a robust tip associate to a thick and cortical base, potentially aim to dig.In the South-East France during the Middle Pleistocene the biface doesn’t appears to be a multifunctional tool. This term cover here different bifacial tool group with diverse functional potentiality. Two principal functions – longitudinal translation and indirect pitch percussion- are associate to bifacial tools presenting specific morphology. It is possible to observe a different use of the bifacial “faconnage” depending the deposit. Bifacial tools are not represent in the same way, reflecting extrinsic or intrinsic constraint and adding variability for the Acheulean definition

Cyril Viallet (2016) — Potentiel fonctionnel des outils bifaciaux au Pléistocène moyen en contexte méditerranéen. Analyse de la structure et des macro-traces des outils bifaciaux de la Caune de l’Arago, Terra Amata, Orgnac 3 et du Lazaret, Thèse soutenue le 24 octobre 2016 à l’université de Perpignan « Via-Domitia »

Viallet Cyril. Cyril Viallet (2016) — Potentiel fonctionnel des outils bifaciaux au Pléistocène moyen en contexte méditerranéen. Analyse de la structure et des macro-traces des outils bifaciaux de la Caune de l’Arago, Terra Amata, Orgnac 3 et du Lazaret, Thèse soutenue le 24 octobre 2016 à l’université de Perpignan « Via-Domitia ». In: Bulletin de la Société préhistorique française, tome 114, n°2, 2017. pp. 384-386