507 research outputs found
Karsts, Paysages et Préhistoire
Collection edytem n°13Les Gorges de lâArdĂšche. Quelle pouvait ĂȘtre lâimpression dâun Homme parcourant celles-ci il y a plus de 30 000ans ? Quel regard portait-il sur ces versants abrupts, ces roches calcaires aux formes spectaculaires et ses nombreuxporches et autres abris sous roche ? Quelle conscience avait-il de leurs prolongements souterrains, dans la pĂ©nombredâabord, dans lâobscuritĂ© des grottes ensuite ? Force est de relever que ces diffĂ©rentes interrogations nâont pas derĂ©ponse car quels que soient les modes dâinvestigation, il nâest guĂšre possible de reconstituer ce qui est au plus profondde nous, les pensĂ©es, et ce dâautant moins si elles sont contemporaines dâune pĂ©riode sans Ă©crit, comme câest lecas de la PrĂ©histoire. Cette absence de rĂ©ponse ne signifie pas quâil ne faille pas se pencher sur ces questions, bienau contraire, et sur la place des paysages, des monuments naturels, de lieux particuliers comme les grottes dans leschoix des Hommes de la PrĂ©histoire pour les explorer, les amĂ©nager, les utiliser comme supports de reprĂ©sentationset de transmission des savoirs. Ne pouvant rĂ©pondre directement Ă ces interrogations, il est nĂ©cessaire de dĂ©finir desmodes de recherche permettant de bĂątir des hypothĂšses les plus robustes possibles pour apprĂ©hender au mieux lesreprĂ©sentations et les actions des Hommes de la PrĂ©histoire. La robustesse de ces hypothĂšses repose, Ă la fois, sur lesdonnĂ©es produites par les diffĂ©rents champs de recherche souhaitant sâinvestir sur ces questions et sur la multiplicitĂ©des travaux sur diffĂ©rents terrains et aires culturelles. Cet ouvrage sâinscrit dans cette dĂ©marche en croisant diffĂ©rentsregards sur les paysages et patrimoines du Sud-ArdĂšche
Karsts de montagne : géomorphologie, patrimoine et ressources.
Actes du Colloque organisé à Sion (Suisse) le 15 septembre 2006 dans le cadre des Journées de l'Association Française de Karstologie. C'est au sein des grandioses paysages karstiques des montagnes du Valais (Suisse) que la réunion annuelle de l'Association Française de Karstologie, organisée du 14 au 17 septembre 2006, a abordé cette problématique. Le colloque qui ouvrait ces journées de l'AFK, a réuni 38 personnes provenant de 4 pays (France, Suisse, Slovénie et Hongrie). 18 communications ont été présentées et réparties en trois sessions (karstologie physique et spéléologie ; explorations géographiques ; karst et patrimoine). Cet ouvrage qui réunit 15 contributions issues des communications, débute par un article de Jean Nicod, qui rappelle que les relations entre l'AFK et les karstologues suisses ne sont pas nouvelles et qu'une réunion similaire avait été organisée en Suisse en 1978, sous l'experte direction des spécialistes du karst alpin (Alfred Bögli) et jurassien (Daniel Aubert). Les autres contributions ont été réparties en trois parties qui reprennent les sessions du colloque : 1 - Connaissance des phénomÚnes karstiques... 2 - Pour une gestion raisonnées des ressources et patrimoines du karst 3 - Application au massif de Tsanfleuro
L'outil-frise : une expérimentation interdisciplinaire: Comment représenter des processus de changements en territoires de montagne ?
Ont Ă©galement contribuĂ© Ă cette publication : Denis Laforgue ; Sandrine Tolazzi ; Sophie Madelrieux ; PĂ©nĂ©lope Lamarque ; Sabine Girard ; MĂ©lanie Duval ; Suzanne Berthier-Foglar ; Philippe Bourdeau ; Anouk Bonnemains ; Hugues FrançoisInternational audienceLe LabEx Innovation et Territoires de Montagne a pour ambition de construire une communautĂ© de recherche en sciences humaines et sociales travaillant sur la montagne. Dans cette dynamique, un collectif de chercheurs issus de diffĂ©rents champs disciplinaires et de parcours variĂ©s sâest proposĂ© de dĂ©velopper une dĂ©marche de recherche qui dĂ©passe les clivages disciplinaires par la formalisation dâun outil de dialogue sur le changement territorial. Ce carnet expose la construction, les enjeux et les rĂ©sultats dâune telle dĂ©marche. Celle-ci a conduit Ă la mise en place dâun dispositif comprenant lâĂ©laboration de documents-ressources, lâexpĂ©rimentation collective dâune mĂ©thode sur diffĂ©rents systĂšmes territoriaux de montagne, lâĂ©change en sĂ©minaires, ainsi que les retours critiques individuels et collectifs sur les apports dâune telle expĂ©rimentation. Au cĆur de ce dispositif, « lâoutil-frise », un outil de reprĂ©sentation synthĂ©tique et globale des changements territoriaux, qui permet de visualiser les co-Ă©volutions et les interactions des composantes dâun processus complexe. Il implique une mise en perspective processuelle de lâobjet dâĂ©tude, Ă savoir lâidentification de la nature des mouvements et des moteurs facteurs de changements. Les enjeux Ă©pistĂ©mologiques et mĂ©thodologiques des diffĂ©rentes approches disciplinaires du changement ont ainsi pu ĂȘtre abordĂ©s, et notamment les concepts de rupture, de bifurcation, dâadaptation ou de transition territoriales
A Pleistocene charcoal drawing or painting from northern Australia
Although claims are often made that Australia has evidence of some of the oldest rock art in the world and features prominently in rock art studies globally, very little of it is securely dated. Recently the first Pleistocene date for pigment art (painting, drawing, stencil or print) in Arnhem Land was obtained, arguably representing one of the oldest securely dated fragments of buried rock art in Australia (see Aubert 2012 and David et al. 2013a for recent reviews on dating rock art in Australia)
Effect of cardiopulmonary bypass on activated partial thromboplastin time waveform analysis, serum procalcitonin and C-reactive protein concentrations
Abstract Introduction Systemic inflammatory response syndrome (SIRS) is a frequent condition after cardiopulmonary bypass (CPB) and makes conventional biological tests fail to detect postoperative sepsis. Biphasic waveform (BPW) analysis is a new biological test derived from activated partial thromboplastin time that has recently been proposed for sepsis diagnosis. The aim of this study was to investigate the accuracy of BPW to detect sepsis after cardiac surgery under CPB. Methods We conducted a prospective study in American Society of Anesthesiologists' (ASA) physical status III and IV patients referred for cardiac surgery under CPB. Procalcitonin (PCT) and BPW were recorded before surgery and every day during the first week following surgery. Patients were then divided into three groups: patients presenting no SIRS, patients presenting with non-septic SIRS and patients presenting with sepsis. Results Thirty two patients were included. SIRS occurred in 16 patients (50%) including 5 sepsis (16%) and 11 (34%) non-septic SIRS. PCT and BPW were significantly increased in SIRS patients compared to no SIRS patients (0.9 [0.5-2.2] vs. 8.1 [2.0-21.3] ng/l for PCT and 0.10 [0.09-0.14] vs. 0.29 [0.16-0.56] %T/s for BPW; P < 0.05 for both). We observed no difference in peak PCT value between the sepsis group and the non-septic SIRS group (8.4 [7.5-32.2] vs. 7.8 [1.9-17.5] ng/l; P = 0.67). On the other hand, we found that BPW was significantly higher in the sepsis group compared to the non-septic SIRS group (0.57 [0.54-0.78] vs. 0.19 [0.14-0.29] %T/s; P < 0.01). We found that a BPW threshold value of 0.465%T/s was able to discriminate between sepsis and non-septic SIRS groups with a sensitivity of 100% and a specificity of 93% (area under the curve: 0.948 +/- 0.039; P < 0.01). Applying the previously published threshold of 0.25%T/s, we found a sensitivity of 100% and a specificity of 72% to discriminate between these two groups. Neither C-reactive protein (CRP) nor PCT had significant predictive value (area under the curve for CRP was 0.659 +/- 0.142; P = 0.26 and area under the curve for PCT was 0.704 +/- 0.133; P = 0.15). Conclusions BPW has potential clinical applications for sepsis diagnosis in the postoperative period following cardiac surgery under CPB
Vers une observation inter-disciplinaire des phénomÚnes naturels sur les bassins versants de montagne (Hydrogéologie à coût limité du bassin du Vorz (Massif de Belledonne, IsÚre))
Le 22 AoĂ»t 2005 une crue intense s'est produite sur le bassin versant du Vorz, dĂ©truisant partiellement le hameau de la Gorge. Cet Ă©vĂšnement a mis en Ă©vidence les difficultĂ©s Ă anticiper les conditions hydromĂ©tĂ©orologiques en montagne oĂč elles sont extrĂȘmement variables spatialement et temporellement, et souvent faiblement instrumentĂ©es. De ce constat est nĂ© le projet de mettre en place un rĂ©seau d'instrumentation hydromĂ©tĂ©orologique original sur le bassin versant du Vorz, afin d'y observer les phĂ©nomĂšnes naturels et hydrologiques s'y produisant, de mieux les apprĂ©hender, et de construire les outils et mĂ©thodes nĂ©cessaires Ă leur modĂ©lisation. AprĂšs deux saisons de mesures, les premiers rĂ©sultats ont montrĂ© que le rĂ©seau mis en place permet d'obtenir des informations Ă haute rĂ©solution spatiale et temporelle sur les processus hydromĂ©tĂ©orologiques. MalgrĂ© son installation dans le milieu difficile de la montagne (accessibilitĂ©, froid, Ă©nergie,...), une trĂšs bonne fiabilitĂ© a pu ĂȘtre mise en avant, ainsi que des perspectives de transposition Ă d'autres bassins versants, et ce, pour un faible coĂ»t financier. L'originalitĂ© du rĂ©seau est de rĂ©aliser un multi-Ă©chantillonnage de nombreux paramĂštres hydromĂ©tĂ©orologiques (pluviomĂ©trie, tempĂ©rature, neige, insolation,...), avec des rĂ©solutions spatiales (10 Ă 50 mĂštres) et temporelles (horaire Ă moins) permettant d'envisager une modĂ©lisation hydrologique Ă diffĂ©rentes Ă©chelles, aussi bien pour la gestion des ressources en eau (long terme) que pour la prĂ©vention des crues (court terme). Les capteurs mis en place constituent un ensemble complĂ©mentaire et indissociable de divers instruments de mesure: iButtons (air et sol), totalisateurs, pluviomĂštres, appareils photographiques. La mise au point d'un capteur de mesure innovant de cartographie automatique de la couverture neigeuse (SnoDEC), Ă partir d'images photographiques classiques, prises Ă pas de temps rĂ©gulier (5 Ă 7 images par jours) a Ă©tĂ© rĂ©alisĂ©e au cours de ce travail. Il permet de quantifier l'hĂ©rogĂ©nĂ©itĂ© spatiale et temporelle des phĂ©nomĂšnes d'enneigement sur le versant, prĂ©pondĂ©rants sur son hydrologie, au vue de la persistance nivale (5 Ă 10 mois). L'ensemble de ce dispositif permet de disposer d'une importante base de donnĂ©es, et de mettre en oeuvre diffĂ©rentes techniques d'interpolations des variables hydromĂ©tĂ©orologiques sur l'ensemble du bassin versant. Ainsi, des cartographies prĂ©cises du champ de tempĂ©rature et de pluviomĂ©trie seront disponibles au pas de temps journalier. En outre, le capteur SnoDEC permettra d'analyser et quantifier l'hĂ©tĂ©rogĂ©nĂ©titĂ© spatio-temporelle (altitude, exposition, vitesse de fonte,...) de la couverture nivale. A partir de ces donnĂ©es, on pourra mieux apprĂ©hender les mĂ©canismes hydrologiques en jeu sur le site et dessiner les contours des modĂ©lisations futures. Dans le mĂȘme temps, les donnĂ©es disponibles pourront ĂȘtre combinĂ©es afin de mettre en Ă©vidence des phĂ©nomĂšnes difficilement mesurables (limite pluie/neige, inversion thermiques,...), qui serviront Ă l'avenir Ă contraindre de maniĂšre prĂ©cise les modĂšles nivologiques et hydrologiques. Au travers des diffĂ©rents paramĂštres instrumentĂ©s, et grĂące Ă l'utilisation de l'imagerie, ce rĂ©seau est capable de mesurer des variables relevant de nombreux champs disciplinaires (dynamique glaciaire, cyle vĂ©gĂ©tatif,...). Il s'inscrit ainsi, par son approche interdisciplinaire, dans une volontĂ© de mise en place d'un rĂ©seau de mesure Ă coĂ»t limitĂ©, destinĂ© Ă l'ensemble des acteurs de l'Ă©tude et la recherche des milieux de la montagne.In August 2005, a intense flashflood occurs on the Vorz catchment affecting the village of Saint-AgnĂšs. This event highlighed the difficulties to forecast the hydrometeorological conditions in mountain areas where they are extremely variable in space and time (spatially and temporally) and frequently poored monitored. From this observation a project was funded to implement an original meteorological monitoring system on the catchment, in order to observe the natural and hydrologic phenomena to better understand them and to build methods and tools for their modeling. After two years of monitoring, the first results showed that the network implement allows to obtain informations on hydrometeorological process at high spatial and temporal resolution. In spite of the installation in a harsh mountain environment (access, cold, energy,...) a very good reliability, and a lot of perspectives of transpositon on other catchments have been point up for low investment costs.The originality of the network is to achieved a multi-sampling on a lot of hydrometeorological parameters (rain, temprature, snow, insulation,...), with spatial (10 to 50 meters) and temporal (hourly or less) resolution to performed a hydrological modeling at different scale both for the water ressource management (long term) or flashflood prevention (short term). The Sensors use in the network constitute a complementary and indivisible set of monitoring system: iButtion (air and soil temperature), rain gauge, totalizer, cameras. The development of an innovative sensor for automatic cartography of the snow cover (SnoDEC) from terrestrail photographies was achived during this work. This sensor allows to quantify spatial and temporal heterogeneity of snow cover evolution on the catchment, with images taken at regular time steps (5 to 7 frames per day). This heterogenity is essential for understand and modelling the hydrology considering the strong snow persistence (5 to 10 months). The dense network set up on the catchment enable us to collect a large database and implement different interpolation techniques on hydrometeorological process on the catchment. Thus, accurate maps of temperatures and rain are created with a daily or hourly timestep. Furthermore, the SnoDEC sensor will permit to analyse and quantify the spatial and temporal heterogeneity (elevation, aspect, velocity of melting,...) of the snow cover. From the database, we will better understand the hydrological mechanisms occuring on the site, and we will build the first ideas and method for the future modelisation. In the same time, the available data will be combinate in order to highlight phenomena very difficult to measure (rain/snow limit, thermical inversion,...) and that will be use in the future to constraint accurately the snow and hydrologic models. Because of the different parameters monitored and the use of imagery, the network is able to measure variables from many field of study (glacier dynamic, vegetative cycle,...). Thereby, with its interdisciplinary approach the network think to implement a monitoring system at low cost in destination of the actors of study and research in mountain.SAVOIE-SCD - Bib.Ă©lectronique (730659901) / SudocGRENOBLE1/INP-Bib.Ă©lectronique (384210012) / SudocGRENOBLE2/3-Bib.Ă©lectronique (384219901) / SudocSudocFranceF
Couplage Flux-Expert / Fluent : application à la modélisation 3D d'un électrolyseur à production d'hydrogÚne
Les Ă©lectrolyseurs Ă production d'hydrogĂšne de type Westinghouse sont des dispositifs Ă©lectrochimiques constituĂ©s d'un empilement de compartiments cathodiques et anodiques sĂ©parĂ©s par une membrane. Ils abritent un ensemble de phĂ©nomĂšnes physiques couplĂ©s. Pour modĂ©liser ces installations nous avons dĂ©veloppĂ© un couplage entre les logiciels FluentÂź (volumes finis) et Flux-ExpertÂź (Ă©lĂ©ments finis). Le premier est utilisĂ© pour la rĂ©solution de la partie thermo-hydraulique du problĂšme, le second pour la partie Ă©lectrocinĂ©tique avec surtensions d'activation. Leur couplage met en Ćuvre un processus itĂ©ratif dans lequel chacun calcule des grandeurs physiques et les transmet Ă l'autre. Ces interpolations de grandeurs d'un maillage sur l'autre nĂ©cessitent une localisation des points de calcul sur des rĂ©gions volumiques ou surfaciques 3D. Une librairie de passation de messages simple et robuste permet aux deux codes de communiquer
Interpreting the mammal deposits of Cloggs Cave (SE Australia), GunaiKurnai Aboriginal Country, through community-led partnership research
Palaeontological animal bone deposits are rarely investigated through research partnerships where the local First Nations communities have a defining hand in both the research questions asked and the research processes. Here we report research undertaken through such a partnership approach at the iconic archaeological site of Cloggs Cave (GunaiKurnai Country, East Gippsland), in the southern foothills of SE Australia's Great Dividing Range.
A new excavation was combined with detailed chronometric dating, high-resolution 3D mapping and geomorphological studies. This allowed interpretation of a sequence of stratigraphic layers spanning from a lowermost excavated mixed layer dated to between 25,640 and 48,470 cal BP, to a dense set of uppermost, ash layers dated to between 1460 and 3360 cal BP. This long and well-dated chronostratigraphic sequence enabled temporal trends in the abundant small mammal remains to be examined.
The fossil assemblage consists of at least 31 taxa of mammals which change in proportions through time. Despite clear evidence that the Old Ancestors repeatedly carried vegetation into the cave to fuel cool fires (no visible vegetation grows in Cloggs Cave), we observed little to no evidence of cooking fires or calcined bone, suggesting that people had little involvement with the accumulation of the faunal remains. Small mammal bones were most likely deposited in the cave by large disc-faced owls, Tyto novaehollandae (Masked Owl) or Tyto tenebricosa (Sooty Owl).
Despite being well dated and largely undisturbed, the Cloggs Cave assemblage does not appear to track known Late Quaternary environmental change. Instead, the complex geomorphology of the area fostered a vegetation mosaic that supported mammals with divergent habitat preferences. The faunal deposit suggests a local ancestral landscape characterised by a resilient mosaic of habitats that persisted over thousands of years, signalling that the Old Ancestors burned landscape fires to encourage and manage patches of different vegetation types and ages within and through periods of climate change
The use of passive seismological imaging in speleogenetic studies: an example from Kanaan Cave, Lebanon
Among many parameters that control the evolution of caves stands the volume of unconsolidated clay sediments generally produced by the alteration of the calcareous rocks. Here we introduce the use of a passive seismological imaging technique to investigate the clay deposits and estimate its total volume in a cave. Applied for the first time for speleogenesis studies, the HVSR (Horizontal / Vertical Spectral Ration) is a geophysical technique that can help better interpret cave geomorphology. We apply seismological spectral techniques (H/V ratio) on ambient noise vibrations to derive the clay volume, as well as its shape. This technique applied on the clay volume reveals some internal details, such as fallen blocks prior to the deposit accumulation and helps to understand deposit evacuation dynamics. The study focuses on the Kanaan Cave, located in Metn District, Lebanon, and reveals new stages related to the cave speleogenesis. This technique could be applied on âparageneticâ caves where clay volume is frequently present in order to constrain the clay volume and reconstruct the buried floor shape of the cave, underneath the clay deposit
Geomorphological context and formation history of Cloggs Cave: What was the cave like when people inhabited it?
New research undertaken at Cloggs Cave, in the foothills of the Australian Alps, employed an integrated geological-geomorphological-archaeological approach with manifold dating methods and fine resolution LiDAR 3D mapping. Long-standing questions about the siteâs chronostratigraphy (e.g. the exact relationship between basal megafaunal deposits and archaeological layers), sedimentation processes and geomorphic changes were resolved. The caveâs formation history was reconstructed to understand its changing morphology and morphogenic processes, and to clarify how these processes shaped the caveâs deposits. Key findings include the identification of: 1) the geomorphological processes that caused the lateral juxtaposition of 52,000 year-old megafaunal and later occupational layers; 2) the existence of one and possibly two (now-buried) palaeo-entrance(s) that enabled now-extinct megafauna and extant large fauna to enter the cave, most likely via a free-roaming passage rather than a pit drop; 3) morphological changes to the cave during the time of the Old People, including the timing of changes to the inclination of palaeo-surfaces; and 4) modifications to stalactites, crushing of calcite formations for the manufacture of powder, construction of a stone arrangement, and movement of large limestone blocks by the Old People. Ultimately, these findings demonstrate that to properly understand what Cloggs Cave was like when the Old People visited the site requires the construction of a narrative that spans some 400 million years and the development of an approach capable of integrating the many scales and processes (e.g. geological, geomorphological, archaeological) that configured to shape the site
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