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Documentary climate data describe evidence of past climate arising from predominantly written historical documents such as diaries, chronicles, newspapers, or logbooks. Over the past decades, historians and climatologists have generated numerous document-based time series of local and regional climates. However, a global dataset of documentary climate time series has never been compiled, and documentary data are rarely used in large-scale climate reconstructions. Here, we present the first global multi-variable collection of documentary climate records. The dataset DOCU-CLIM comprises 621 time series (both published and hitherto unpublished) providing information on historical variations in temperature, precipitation, and wind regime. The series are evaluated by formulating proxy forward models (i.e., predicting the documentary observations from climate fields) in an overlapping period. Results show strong correlations, particularly for the temperature-sensitive series. Correlations are somewhat lower for precipitation-sensitive series. Overall, we ascribe considerable potential to documentary records as climate data, especially in regions and seasons not well represented by early instrumental data and palaeoclimate proxies.

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The isotopic compositions of oxygen (δ18O) and hydrogen (δ2H) are widely used to locate the geo- graphical origin of biological remains or manufactured products. In this paper, we analyse the distributions of δ18O and δ2H in tap waters sampled across France, and in precipitation interpolated with the Online Isotopes in Precipitation Calculator and modelled with the isotope-enabled ECHAM6-wiso model. Our aim is to provide isoscapes usable in archaeology and forensics and evaluate whether the modelled data could be surrogates for measured ones. The δ18O and δ2H in the 396 tap waters sampled varied spatially within a range of 10‰ and 77‰, respectively. Their consistent distributions followed rules summarized by the effects of altitude and dis- tance from the coast. Their variations along the year were small. Therefore, the database provides a solid ref- erence for δ18O and δ2H of the water supply system at the regional scale. The areas with the most uncommon oxygen and hydrogen isotopic compositions (Atlantic coast south of Brittany and the highest elevations in the Alps) are the most accurately traceable areas in provenancing studies. The isotopic compositions of modelled precipitation have the same spatial distributions but different absolute values from those of tap waters. There- fore, our results favour the use of statistical isoscapes rather than general circulation model-based isoscapes in provenancing studies.

The prognostic role of decongestion-related change of cardiac morphology and in particular right heart function has not been investigated comprehensively in AHF patients. This prospective observational single-centre study included consecutive patients hospitalized for treatment of AHF with reduced, mildly-reduced or preserved left ventricular ejection fraction (LVEF). Comprehensive transthoracic echocardiography at admission and discharge assessed decongestion-related change of cardiac function and morphology. The combined endpoint of 1 year all-cause mortality and cardiovascular rehospitalization explored the prognostic importance of decongestion-related change. The 176 study participants were 83 years old [74-87] and 54% were men. Fifty one (29%) had rLVEF, 65 (37%) mrLVEF, and 60 (34%) pLVEF. The proportion of de novo or worsening chronic HF was not different between LVEF groups. HF aetiology and cardiovascular risk factors were equally distributed across all groups except for a higher BMI in the pLVEF group. Decongestion equally reduced body weight, heart rate, systolic and diastolic blood pressure, tricuspid regurgitation gradient, and inferior vena cava diameter across all groups (P < 0.004 for all). Decongestion-related increase in TAPSE independent of the LVEF was associated with improvement of right-ventricular-pulmonary artery coupling and a lower incidence of the combined outcome in the Cox proportional hazard risk analysis (unadjusted HR 0.50 95% CI 0.33-0.78, P = 0.002; adjusted HR 0.46 95% CI: 0.33-0.78, P = 0.001). Decongestion-related increase in TAPSE and recovery of RV/pulmonary artery coupling was observed across all LVEF groups and associated with a risk reduction for the combined endpoint highlighting the important prognostic role of right heart recovery after an AHF episode.

Aim The aim was to decipher Europe‐wide spatio‐temporal patterns of forest growth dynamics and their associations with carbon isotope fractionation processes inferred from tree rings as modulated by climate warming. Location Europe and North Africa (30‒70° N, 10° W‒35° E). Time period 1901‒2003. Major taxa studied Temperate and Euro‐Siberian trees. Methods We characterize changes in the relationship between tree growth and carbon isotope fractionation over the 20th century using a European network consisting of 20 site chronologies. Using indexed tree‐ring widths (TRWi), we assess shifts in the temporal coherence of radial growth across sites (synchrony) for five forest ecosystems (Atlantic, boreal, cold continental, Mediterranean and temperate). We also examine whether TRWi shows variable coupling with leaf‐level gas exchange, inferred from indexed carbon isotope discrimination of tree‐ring cellulose (Δ13Ci). Results We find spatial autocorrelation for TRWi and Δ13Ci extending over a maximum of 1,000 km among forest stands. However, growth synchrony is not uniform across Europe, but increases along a latitudinal gradient concurrent with decreasing temperature and evapotranspiration. Latitudinal relationships between TRWi and Δ13Ci (changing from negative to positive southwards) point to drought impairing carbon uptake via stomatal regulation for water saving occurring at forests below 60° N in continental Europe. An increase in forest growth synchrony over the 20th century together with increasingly positive relationships between TRWi and Δ13Ci indicate intensifying impacts of drought on tree performance. These effects are noticeable in drought‐prone biomes (Mediterranean, temperate and cold continental). Main conclusions At the turn of this century, convergence in growth synchrony across European forest ecosystems is coupled with coordinated warming‐induced effects of drought on leaf physiology and tree growth spreading northwards. Such a tendency towards exacerbated moisture‐sensitive growth and physiology could override positive effects of enhanced leaf intercellular CO2 concentrations, possibly resulting in Europe‐wide declines of forest carbon gain in the coming decades. Spanish Government, Grant/Award Number: AGL2015‐68274 ‐C3 ‐3‐R; Sixth Framework Programme, Grant/AwardNumber: EVK2‐2001 ‐00237; Seventh Framework Programme, Grant/AwardNumber: COST ‐STSM ‐ECOST ‐STSM ‐FP1304‐140915‐066395 and ERANET‐Mundus program (Grant agreement 20112573)

International audience;  Tree-ring stable oxygen isotopes of Polylepis tarapacana record austral summer precipitation variability in the South American Altiplano.  El Niño-Southern Oscillation is imprinted in the tree-ring oxygen isotopes with a stronger signal towards the north of the studied area.

In this chapter we introduce the climate signal in stable isotope tree-ring records, with the emphasis on temperate forests. The development of the subdiscipline is recapped followed by an exploration of isotope dendroclimatic records by geography and, broadly, by isotopic species. Whilst there are still questions to be answered around signal strength and age-related effects in different environments and in different species, the proxy is now contributing to palaeoclimatology in a far greater way than in the days of the first hints of ‘isotope tree thermometers’. We include two summary tables. Table 19.1 exemplifies the range of climate information available from stable carbon isotope time series and Table 19.2 explores oxygen isotope proxy signals. Due to the greater complexity seen in stable carbon isotope interpretations we explore response groupings with example references given for each category of proxy response. Finally, we summarize the state of the art in isotope dendroclimatology and discuss possible future directions.

Gradual anthropogenic warming and parallel changes in the major global biogeochemical cycles are slowly pushing forest ecosystems into novel growing conditions, with uncertain consequences for ecosystem dynamics and climate. Short-term forest responses (i.e., years to a decade) to global change factors are relatively well understood and skilfully simulated by land surface models (LSMs). However, confidence on model projections weaken towards longer time scales and to the future, mainly because the long-term responses (i.e., decade to century) of these models remain unconstrained. This issue limits confidence on climate model projections. Annually-resolved tree-ring records, extending back to pre-industrial conditions, have the potential to constrain model responses at interannual to centennial time scales. Here, we constrain the representation of tree growth and physiology in the ORCHIDEE global land surface model using the simulated interannual variability of tree-ring width and carbon (Δ13C) and oxygen (δ18O) stable isotopes in six sites in boreal and temperate Europe. The model simulates Δ13C (r = 0.31-0.80) and δ18O (r = 0.36-0.74) variability better than tree-ring width variability (r < 0.55), with an overall skill similar to that of other state-of-the-art models such as MAIDENiso and LPX-Bern. These results show that growth variability is not well represented, and that the parameterization of leaf-level physiological responses to drought stress in the temperate region can be improved with tree-ring data. The representation of carbon storage and remobilization dynamics is critical to improve the realism of simulated growth variability, temporal carrying over and recovery of forest ecosystems after climate extremes. The simulated physiological response to rising CO2 over the 20th century is consistent with tree-ring data in the temperate region, despite an overestimation of seasonal drought stress and stomatal control on photosynthesis. Photosynthesis correlates directly with isotopic variability, but correlations with δ18O combine physiological effects and climate variability impacts on source water signatures. The integration of tree-ring data (i.e. the triple constraint: width, Δ13C and δ18O) and land surface models as demonstrated here should contribute towards reducing current uncertainties in forest carbon and water cycling.

International audience; Die in diesem Band versammelten Beiträge entstanden im Rahmen eines von der Sorbonne Nouvelle initiierten dreijährigen internationalen Projekts zum Thema ‚Textanfängeʻ mit der Jagiellonen Universität Krakau (Polen) und mit der Alpen-Adria-Universität Klagenfurt (Österreich), in dessen Verlauf drei Treffen stattgefunden haben. Erste Ergebnisse der Zusammenarbeit wurden in Duś / Kołodziej / Konieczna-Serafin (Duś, M., Kołodziej, R. & Konieczna-Serafin, J. (Hrsg.). (2017). Textanfänge – Semantische Aspekte. (= Studien zur Text- und Diskursforschung, 17). Frankfurt a. M.: Peter Lang.) und in Krieg-Holz / Schütte (Krieg-Holz, U. & Schütte, C. (Hrsg.). (2018). Textanfänge. Konzepte und Analysen aus linguistischer, literaturwissenschaftlicher und didaktischer Perspektive. (= Texte und Diskurse, 3), Berlin: Frank & Timme) veröffentlicht.

Tree growth is generally considered to be temperature limited at upper elevation treelines, yet climate factors controlling tree growth at semiarid treelines are poorly understood. We explored the influence of climate on stem growth and stable isotopes for Polylepis tarapacana Philipi, the world���s highest elevation tree species, which is found only in the South American Altiplano. We developed tree-ring width index (RWI), oxygen (�������O) and carbon (������C) chronologies for the last 60 years at four P. tarapacana stands located above 4400 m in elevation, along a 500 km latitude aridity gradient. Total annual precipitation decreased from 300 to 200 mm from the northern to the southern sites. We used RWI as a proxy of wood formation (carbon sink) and isotopic tree-ring signatures as proxies of leaf-level gas exchange processes (carbon source). We found distinct climatic conditions regulating carbon sink processes along the gradient. Current growing-season temperature regulated RWI at northern-wetter sites, while prior growing-season precipitation determined RWI at arid southern sites. This suggests that the relative importance of temperature to precipitation in regulating tree growth is driven by site water availability. By contrast, warm and dry growing seasons resulted in enriched tree-ring ������C and �������O at all study sites, suggesting that similar climate conditions control carbon-source processes along the gradient. Site-level ������C and �������O chronologies were significantly and positively related at all sites, with the strongest relationships among the southern drier stands. This indicates an overall regulation of intercellular carbon dioxide via stomatal conductance for the entire P. tarapacana network, with greater stomatal control when aridity increases. This manuscript also highlights a coupling (decoupling) between physiological processes at leaf level and wood formation as a function of similarities (differences) in their climatic sensitivity. This study contributes to a better understanding and prediction of the response of high-elevation Polylepis woodlands to rapid climate changes and projected drying in the Altiplano.

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The ratio of leaf internal (ci ) to ambient (ca ) partial pressure of CO2 , defined here as χ, is an index of adjustments in both leaf stomatal conductance and photosynthetic rate to environmental conditions. Measurements and proxies of this ratio can be used to constrain vegetation model uncertainties for predicting terrestrial carbon uptake and water use. We test a theory based on the least-cost optimality hypothesis for modelling historical changes in χ over the 1951-2014 period, across different tree species and environmental conditions, as reconstructed from stable carbon isotopic measurements across a global network of 103 absolutely dated tree-ring chronologies. The theory predicts optimal χ as a function of air temperature, vapour pressure deficit, ca and atmospheric pressure. The theoretical model predicts 39% of the variance in χ values across sites and years, but underestimates the intersite variability in the reconstructed χ trends, resulting in only 8% of the variance in χ trends across years explained by the model. Overall, our results support theoretical predictions that variations in χ are tightly regulated by the four environmental drivers. They also suggest that explicitly accounting for the effects of plant-available soil water and other site-specific characteristics might improve the predictions.

Aims Mild or moderate aortic regurgitation (AR) has only little effect on cardiovascular outcome in people with normal left ventricular ejection fraction (EF); therefore, it is not perceived as a major clinical problem. This study investigates whether mild or moderate AR is associated with increased short‐term mortality in patients hospitalized for treatment of acute heart failure (AHF) and whether mild or moderate AR impacts differently on short‐term mortality in AHF patients with reduced EF (AHFrEF), mid‐range EF (AHFmrEF), or preserved EF (AHFpEF). Methods and results This mono‐centric study included 505 consecutive adult patients hospitalized for de novo or worsening chronic HF not related to acute ischaemia or severe valvular pathology in the echocardiogram at index hospitalization. Cox regression analysis studied the impact of AR on all‐cause mortality (ACM) over the 150 days' study period. Mild or moderate AR was associated with increased ACM (HR 1.75 [95% CI: 1.1–2.7]; P = 0.009). The prevalence of mild or moderate AR in the study population was 42% and not significantly different between AHFpEF (n = 227), AHFmrEF (n = 86), and AHFrEF (n = 192) study participants (37.9% vs. 50.0% vs. 42.7%; P = 0.144). In AHFpEF patients, the age‐adjusted hazard for ACM was increased in patients with AR compared with patients without AR (HR 2.17 [95% CI: 1.1–4.2]; P = 0.002). The age‐adjusted hazard for ACM was increased by a trend in AHFmrEF with AR (HR 7.11, [95% CI: 0.9–57.8]; P = 0.067) and not different between the AHFrEF groups (HR 0.95 [95% CI: 0.5–1.8]; P = 0.875). Conclusions Mild or moderate AR increased ACM only in AHFpEF patients, highlighting a distinct clinical relevance.

Modelling of the oxygen isotopic composition (δ18O) of tree-ring cellulose rely on the isotopic equilibrium assumption between the atmospheric water vapor and the tree source water, which is frequently assimilated to integrated precipitation. We explore the veracity of this assumption based on observations collected (δ18O of rain, rivers, leaves, tree-rings) or monitored (δ18O of water vapor) during a field campaign in Río Negro province, Argentina, in late summer 2017 (February-March). We examine, firstly, how the δ18O of water vapor deviate from the equilibrium with precipitation and, secondly, what is the impact of the isotopic equilibrium assumption on the calculation of the isotopic composition of tree-ring cellulose. For oxygen, the isotopic disequilibrium between rain and vapor range between -2.0 and 4.1‰. Rain drops re-evaporation during their fall, evaporation of soil water and vegetation transpiration (resulting in transpired water accounting for 14 to 29% of ambient water vapor) could produce this disequilibrium. The small value of the disequilibrium at the study site is likely due to the high level of relative humidity (from 70 to 96%) favoring the isotopic diffusive exchanges between the two water phases and thus promoting the isotopic equilibrium. A perfect agreement between observed and calculated isotopic composition of cellulose is obtained if the source water is assumed to be in isotopic equilibrium with the measured water vapor. This hypothetical source water has a significantly higher δ18O than the expected averaged isotopic composition of precipitation over the growing period or than the groundwater (river value). The veracity of the hypothesis of the isotopic equilibrium between water vapor and source water in tree-ring paleoclimate studies is discussed in light of these results.

The central Andes have undergone a drying trend over the last decades with adverse socioeconomic effects throughout the south of Argentina and Chile. The long-term precipitation variability in this region has been associated with modes of sea surface temperature (SST) and atmospheric circulation variability acting at decadal-to-multidecadal timescales, such as the Interdecadal Pacific Oscillation and the Southern Annular Mode. More recently, the drying long-term trend of precipitation in central Andes has also been linked to a poleward expansion of the Hadley Cell (HC) in the Southern Hemisphere over the last decades. In previous works several possible causes of the HC expansion have been proposed, involving both external forcing (e.g., greenhouse gases and ozone depletion effects) and internal climate variability (e.g., SST and atmospheric modes).In this work the origin and the causes of the central Andes precipitation variability at decadal-to-longer time scales are studied. For this purpose, the main modes of climate variability that modulate the central Andes precipitation are first identified. Then the changes of these modes and their influence on precipitation are attributed to different factors of external forcing or to internal climate variability. For this analysis large ensembles of different climate simulations and detection-and-attribution experiments performed with the IPSL-CM6A-LR model are used.

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Supplementary figure 1: Linear relationship for Europe for monthly δ2H and δ18O values

Climate reconstructions in temperate Europe have been widely based on oak species. However, other co‐occurring species, largely distributed in Europe, may be used for recording climate variability. In this paper, we documented the inter‐trees and inter‐species variations over 1960‐2007 of oxygen and carbon isotopic compositions in ring cellulose of F. sylvatica, P. sylvestris and Q. petraea co‐occurring in the Fontainebleau forest (France). Our results indicated that large levels of series replication (11 trees on average) were required to generate isotopic mean series representative of the populations. We calculated mean isotopic ratios in pine higher than in the deciduous species, and hypothesized that these contrasts resulted from differences in stomatal conductance, phenology and canopy structure, and, for oxygen, also in water uptake depth and isotopic exchange rate. We found that δ18O and δ13C chronologies were significantly correlated to one another in the three species and responded primarily to air moisture and Tmax, which indicated that stomatal conductance was an important driver of changes in both types of records. We determined that the correlations were strong with the May to July climate variables in F. sylvatica, and with the July and August ones in Q. petraea and P. sylvestris. We showed that the oxygen records were systematically more coherent than those of carbon. This study demonstrated that δ18O, and to a lesser extent δ13C, from the three different species are reliable proxies for reconstructing past hydroclimatic variations in Europe.

Cet article invite a prendre en compte un niveau de figement peu traite en linguistique francaise : le figement des genres textuels. Il est propose une inscription dans la tradition de la linguistique textuelle allemande et une lecture des travaux de Ulla Fix, ou les termes de « modele », « attentes » et « prototypique » jouent un role important, ce qui l’amene a identifier des genres textuels plus ou moins figes et a definir les categories de « genres textuels a citer », « genres textuels a reproduire » et « genres textuels a modele », les trois categories pouvant donner lieu a des detournements : montages et melanges de modeles textuels. Apres ces eclaircissements theoriques et notionnels, nous proposons l’analyse de trois exemples de « jeux de textes », tires de l’aire culturelle francaise, avec les outils de la linguistique textuelle allemande.

International audience; In palaeoclimate reconstructions, the combination of proxy records measured in different climate archives is challenging because of the uncertainties associated with each proxy, but it can also help reduce some of these uncertainties. Here, we present a novel approach to combine speleothem and tree ring proxies for a drought reconstruction of the last 640 years: a fluid inclusion δ 18 O record from a stalagmite from Villars Cave (southwest France) and a tree ring cellulose δ 18 O record of Quercus spp. from the nearby Angoulême area. The δ 18 O of the fluid inclusions is taken as an estimate of the δ 18 O of the trees' source water. Then, the cellulose and source water δ 18 O are used to calculate the leaf water isotopic enrichment, as well as relative humidity, which is the dominant controlling factor of this enrichment. The reconstructed long-term trends in relative humidity differ from a previously published reconstruction of moisture variability based on the tree ring record alone. Further measurements will be necessary to support either reconstruction. Nevertheless, this investigation demonstrates the great potential for combining isotope proxies from speleothems and tree rings to reconstruct both the low-and high-frequency variability of drought.; En paléoclimatologie, la comparaison entre les différentes archives est complexe à cause des incertitudes associées à chaque indicateur ; elle peut cependant aussi aider à réduire les incertitudes. Nous présentons ici une nouvelle approche pour combiner les indicateurs paléoclimatiques issus des spéléothèmes et des cernes d'arbre pour reconstituer les sécheresses au cours des derniers 640 ans : le δ 18 O des inclusions fluides d'une stalagmite de la grotte de Villars (sud-ouest de la France) et le δ 18 O de la cellulose des cernes de chênes (Quercus spp.) proches d'Angoulême. Le δ 18 O des inclusions fluides est considéré comme le δ 18 O de l'eau souterraine qui alimente les arbres. Puis le δ 18 O de la cellulose et celui de l'eau souterraine sont utilisés pour calculer l'enrichis-sement isotopique de l'eau de la feuille ainsi que l'humidité relative qui est le facteur dominant contrôlant cet enrichissement. La variation de l'humidité relative reconstituée diffère des reconstitutions publiées basées uniquement sur les cernes d'arbre suggérant la nécessité de faire d'autres reconstitutions pour mieux comprendre ces différences. Ce travail montre tout l'intérêt de comparer deux archives pour tenter de reconstituer les périodes de sécheresse passées.

The reconstruction of droughts is essential for the understanding of past drought dynamics and can help evaluate future drought scenarios in a changing climate. This article presents a reconstruction of summer droughts in France based on annually resolved, absolutely dated chronologies of oxygen isotope ratios (δ18O) in tree ring cellulose from Quercus spp. Samples were taken from living trees and timber wood from historic buildings at two sites: Fontainebleau (48°23′ N, 2°40′ E; 1326–2000 CE) and Angoulême (45°44′ N, 0°18′ E; 1360–2004 CE). Cellulose δ18O from these sites proved to be a good proxy of summer climate, as the trees were sensitive to temperature and moisture availability. However, offsets in average δ18O values between tree cohorts necessitated a correction before joining them to the final chronologies. Using the corrected δ18O chronologies, we developed models based on linear regression to reconstruct drought, expressed by the standardized precipitation evapotranspiration index (SPEI). The significant correlations between the SPEI and cellulose δ18O (r ≈ −0.70), as well as the verification of the models by independent data support the validity of these reconstructions. At both sites, recent decades are characterized by increasing drought. Fontainebleau displays dominantly wetter conditions during earlier centuries, whereas the current drought intensity is not unprecedented in the Angoulême record. While the δ18O chronologies at the two studied sites are highly correlated during the 19th and 20th centuries, there is a significant decrease in the correlation coefficient between 1600 and 1800 CE, which indicates either a weaker climate sensitivity of the tree ring proxies during this period, or a more heterogeneous climate in the north and the south of France. Future studies of tree ring isotope networks might reveal if the seasonality and spatial patterns of past droughts can explain this decoupling. A regional drought reconstruction based on a combination of the two sites shows good agreement with historical records of grape harvest dates in France, which provide another proxy of summer climate.

Relatório (Estágio curricular) - Universidade Federal de Santa Catarina. Centro de Comunicação e Expressão. Departamento de Expressão Gráfica. Design. Profa. Mônica Stein

Until recent years, detailed studies of hydraulic structures were made almost systematically by hydraulic physical models offering great capabilities to understand the hydraulic behaviour of the studied flows. On the other hand, physical models are in general rather expensive and time consuming, and can only represent some hydraulic phenomenon of interest. This depending on the similarity law for which they have been calibrated. Nowadays, given the increasing computational capabilities and further development of user-friendly interfaces, 3D CFD modelling can balance these issues and provide a flexible and powerful tool to support physical modelling, or even replace it in certain cases. The numerical modelling of complex hydraulic flows is becoming more and more efficient and cost effective, providing a powerful tool for hydraulic analysis, from preliminary to detailed studies. This article describes how the 3D CFD tool has been first validated on a large range of hydraulic phenomena, then how it is exploited by Tractebel on several large projects to analyse and optimize the design or operation of hydraulic structures. Several way to exploit 3D CFD models are developed, either at early stages of the design process, ahead or together with a physical model in order to optimize it exploitation. Application examples are presented, among which the modelling of large gated overflow and orifice spillways … Possibilities and limitations of the 3D CFD tool on these various topics is discussed. Simplified modelling methods has been developed to address specific issues, in an optimized way, among which applications on vertical 2D, and hybrid 2D planar/3D models are presented, the advantages provided by these approaches are highlighted with respect to the addressed issues. The procedures developed for each particular case is described so as to provide indicative frameworks for deploying 3D CFD tools in engineering projects, and provide added value. Based on Tractebel experience, the challenges that have still to be overcome are discussed, with an emphasis put on the modelling of air entrainment. Physical phenomena involved in monophasic flows, however complex, were proven to be well simulated by 3D CFD software. This as long as the modeller has sufficient hydraulic knowledge and experience to adapt a priori the model parameters, mesh and boundary conditions and to carry out an a posteriori critical analysis of the results. In spillway design, this statement applies in particular to the control and conveyance structures, such as channels, weirs, spillway chutes, or flip buckets. When it comes to energy dissipation structures, such as stepped spillways, stilling basins or plunge pools, careful calibration tests of the air entrainment parameters must be performed for each case, questioning the practical and standalone use of current 3D biphasic models in hydraulic engineering. Nevertheless, once the air entrainment parameters have been calibrated, hybrid approach for such complex analyses, combining physical and numerical models, is of main interest, leading to time savings, better physical understanding and enhanced flexibility in the design activities.

Over the last decades, gradual changes in summer climate in the Southern Hemisphere have affected forest growth in contrasting ways in moist and dry regions. Here, we use correlation analysis and a forward process-based model (Vaganov-Shashkin-Lite) to investigate changes in climate limitation of the interannual tree-ring growth of Nothofagus pumilio at the upper treeline along a precipitation gradient in northern Patagonia. Patterns of climate limitation vary consistently along the gradient. At mesic and humid treelines, tree-ring growth is positively related to growing season temperature and negatively to precipitation. At xeric treelines, the opposite is observed. Moreover, the climate-growth relations are not stationary. In particular, according to the model, the step decrease in precipitation in 1952 induced an increase of the moisture limitation at the dry edge of the gradient. Correlation analyses evidence that the dependence of growth on moisture after 1952 has enhanced since 1976. While the model consistently reproduces tree-ring width variations over the 1931-1975 period, it does not capture the growth patterns in the following years. Some environmental parameters (cloudiness, snowpack, atmospheric CO2) affecting moisture, radiation and stomatal aperture may have reached thresholds beyond which the effect on tree-growth has become sizable. Fil: Lavergne, Aliénor. Centre National de la Recherche Scientifique; Francia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; Argentina Fil: Daux, V.. Centre National de la Recherche Scientifique; Francia Fil: Villalba, Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; Argentina Fil: Barichivich, J.. Centre National de la Recherche Scientifique; Francia. University of Leeds; Francia

Inflammation and oxidative stress are related to cancer initiation and progression. We hypothesized that dietary supplementation with a procyanidin-rich Pinus pinaster extract (Pyc) with known antioxidant and anti-inflammatory effects could induce systemic protection, thereby attenuating tumor development. To test our hypothesis, mice were subjected to long-term supplementation (20 days, every 24 h) with saline, 25 mg/kg resveratrol or 100 mg/kg Pyc. Pyc was administered at a maximum tolerated oral dose, previously determined using toxicity indicators. Ten days after Ehrlich ascites tumor induction, weight gain and abdominal circumference increase were calculated. Ascitic fluid from six mice/group was evaluated by determining total volume; tumor packed cell volume; cell viability; tumor cell death type; inflammatory infiltrate; and levels of tumor necrosis factor alpha (TNF-α), interleukin 1 beta (IL-1β), carbonyl proteins, lipid peroxidation, cyclooxigenase-2 (COX-2) expression and Akt phosphorylation (p-Akt). Ten mice/group were monitored to evaluate survival. Pyc and resveratrol were associated with reduced weight gain (>30%), abdominal circumference and ascitic volume. Tumor packed cell volume was reduced in Pyc-supplemented mice (26%), which had the largest tumor cell count reduction (>35%), increased ascitic fluid apoptosis rates (20%) and the longest survival (>2-fold). Pyc and resveratrol treatment both reduced inflammatory infiltrate and levels of TNF-α, IL-1β, carbonyl proteins, lipid peroxidation (~ 30%) and p-Akt (up to 4-fold). Only Pyc significantly inhibited COX-2. Pyc attenuated oxidative and inflammation mediators and impaired tumor development, supporting our hypothesis and suggesting Pyc as a candidate for future studies in multitargeted dietary-based cancer prevention approaches.

Arts de l’espace et arts du temps ? Il existe dans les classifications des arts cette opposition, ancienne et traditionnelle, entre les arts dits de l’espace qui seraient régis par un principe de simultanéité, comme par exemple la peinture, et les arts dits du temps qui seraient régis par un principe de succession, comme par exemple la littérature, une opposition qui donna lieu à des développements célèbres dans le Laocoon (1766) de Lessing : S'il est vrai que la peinture, pour ses imitations...

Hypothesis The ability to identify the stress-strain relations correctly is critical to understanding and modeling any rheological responses of an interface. Langmuir-Pockels (LP) trough is one of the most commonly used tools for studying an interface. Most, if not all, existing studies assume a 1D uniaxial compression during a LP-trough compression experiment. It is hypothesized that the deformation field is far more complex than what is typically assumed. Experiments To examine this hypothesis, we custom-built a glass-bottomed LP trough equipped with a camera to capture a series of optical images as a carbon nanotube (CNT)-laden interface is compressed. A digital image correlation (DIC) technique was then applied to the images to evaluate the global strain field during compression of the CNT laden interface. The DIC-corrected strain data were subsequently analyzed with the surface stress data to quantify the surface shear and dilatational moduli of the CNT-laden interface. Findings Our experimental findings clearly show, for the first time, the development of a non-uniform and complex 2D strain field during compression. The local strains were further quantified and compared with the usual assumption of 1D uniaxial compression. Although the compressive strain averaged over the whole trough area closely resembles the 1D uniaxial compression strain, the 1D compression assumption underestimates the local strain by about 36% at the center of the trough, where the surface stresses are measured. This is the first study in applying the DIC technique to map out the global strain field as a particle-laden interface is compressed. The method may also be applicable to other systems with similar optical texture, allowing the correct identification of stress-strain relationship of an interface.

International audience; Despite instrumental records showing recent large temperature rises on the Tibetan Plateau (TP), only a few tree-ring temperature reconstructions do capture this warming trend. Here, we sampled 260 trees from seven Alpine treeline locations across the southeast TP. Standardized tree-ring width chronologies of Abies squamata and Sabina squamat were produced following Regional Curve Standardization detrending. The leading principal component of these records is well correlated with the regional summer (JJA) minimum temperature (MinT) (R2 = 0.47, P < 0.001, 1953–2009). Hence we produce a regional summer MinT reconstruction spanning the last 212 years. This reconstruction reveals a long-term persistent warming trend, starting in the 1820s, at a rate of 0.45 ± 0.09 °C/century (1820–2009). This trend is also detected since the 1820s in the Asian summer MinT reconstruction produced by the PAGES 2K project, with a very close warming rate (0.43 ± 0.08 °C/century, 1820–1989). Our record also displays an enhanced multi-decadal variability since the mid-twentieth century. The 1990s–2000s are the warmest of our whole record, due to the superposition of the gradual warming trend and decadal variability during this interval. The strongest decadal cooling occurs during the 1950s and the largest warming trend during the 1970s. The magnitude of warming from 1973 to 2003 was larger than the total warming trend from 1820s to 2009. Extreme events are also more frequent since 1950. The pattern of multi-decadal variability has similarities with the Atlantic multi-decadal oscillation, suggesting common causality. CMIP5 historical simulations fail to capture both the magnitude and timing of this multi-decadal variability. The ensemble CMIP5 average produces a steady warming trend starting in the 1970s, which only accounts for about 60 % of the observed warming trend during this period. We conclude that TP summer temperature could reflect a climate response to increased greenhouse gas concentrations, however modulated by multi-decadal variations common with the Atlantic sector.

Over the last decades, dendroclimatologists have relied upon linear transfer functions to reconstruct historical climate. Transfer functions need to be calibrated using recent data from periods where CO2 concentrations reached unprecedented levels (near 400 ppm – parts per million). Based on these transfer functions, dendroclimatologists must then reconstruct a different past, a past where CO2 concentrations were far below 300 ppm. However, relying upon transfer functions calibrated in this way may introduce an unanticipated bias in the reconstruction of past climate, particularly if CO2 has had a noticeable impact on tree growth and water use efficiency since the beginning of the industrial era. As an alternative to the transfer function approach, we run the MAIDENiso ecophysiological model in an inverse mode to link together climatic variables, atmospheric CO2 concentrations and tree growth parameters. Our approach endeavors to find the optimal combination of meteorological conditions that best simulate observed tree ring patterns. We test our approach in the Fontainebleau Forest (France). By comparing two different CO2 scenarios, we present evidence that increasing CO2 concentrations have had a slight, yet significant, effect on the reconstruction results. We demonstrate that realistic CO2 concentrations need to be inputted in the inversion so that observed increasing trends in summer temperature are adequately reconstructed. Fixing CO2 concentrations at preindustrial levels (280 ppm) results in undesirable compensation effects that force the inversion algorithm to propose climatic values that lie outside from the bounds of observed climatic variability. Ultimately, the inversion approach has several advantages over traditional transfer function approaches, most notably its ability to separate climatic effects from CO2 imprints on tree growth. Therefore, our method produces reconstructions that are less biased by anthropogenic greenhouse gas emissions and that are based on sound ecophysiological knowledge.

A tree-ring δ18O chronology of Linzhi spruce, spanning from AD 1781 to 2005, was developed in Bomi, Southeast Tibetan Plateau (TP). During the period with instrumental data (AD 1961–2005), this record is strongly correlated with regional CRU (Climate Research Unit) summer cloud data, which is supported by a precipitation δ18O simulation conducted with the isotope-enabled atmospheric general circulation model LMDZiso. A reconstruction of a regional summer cloud index, based upon the empirical relationship between cloud and diurnal temperature range, was therefore achieved. This index reflects regional moisture variability in the past 225 yr. The climate appears drier and more stable in the 20th century than previously. The drying trend in late 19th century of our reconstruction is consistent with a decrease in the TP glacier accumulation recorded in ice cores. An exceptional dry decade is documented in the 1810s, possibly related to the impact of repeated volcanic eruptions on monsoon flow.

[An assessment of error sources when using grape harvest date for past climate reconstruction]; Several studies have used grape harvest date (GHD) as a proxy for temperature variations of the last centuries in Europe. However, the use of grape harvest dates to reconstruct climate is not straightforward, with four possible causes of major flaws. In this study we identify and evaluate the accuracy of GHD as a proxy to past temperature anomalies, uncertainties in the model used to relate temperature to GHD, identity of the grape varieties cultivated in the past, type of wine produced in the past and cultural practices used in the past. Our analyses are based on several phenological and crop models, and on the most complete data set on grape vine phenology and harvest quality. We show that the two methodologies currently used — linear regression models and process-based phenological models — can be accurate, but process-based phenological models ascertain robustness to be applied confidently in different vineyards and different periods. However, we show that several factors can induce a bias in temperature reconstructions using process-based models. We demonstrate the importance of historical information on the studied areas such as the varieties cultivated, the style of wine produced, the quality sought, the agricultural practices, in order to build the most robust model.

Two new Juniper tree-ring-width (TRW) chronologies spanning more than 500 years were developed in the Yellow River source area, North Eastern Qinghai-Tibetan Plateau (NE-QTP). For the two studied sites, located approximately 50 km apart, split correlation and coherence analysis reveal unstable tree-growth responses to local moisture availability. While significant correlations are obtained with April–June local precipitation, Palmer Drought Severity Index (PDSI) and river flow from 1948/1954 to 1998 and from 1948/1954 to 1970s, these correlations vanish for the time period 1970s-1998. The local instrumental climate data (precipitation, PDSI and river flow) exhibit opposite correlations with large scale modes of variability (El Nino Southern Oscillation, ENSO, and Pacific Decadal Oscillation, PDO) before and after the 1977 PDO shift. One tree-ring chronology is coherent and anti-phased with instrumental ENSO/PDO indices at 5.2-year frequency. On the longer time span, this TRW chronology is compared with PDO reconstructed from historical Chinese data. This comparison also exhibits unstable multi-decadal relationships, notably in the mid 19th century. Altogether, the comparison between our two chronologies, local instrumental climate records, and ENSO/PDO indices suggest a cautious use of local TRW records for paleoclimate reconstructions. Further studies are needed to explore both the spatial coherency of tree-ring records and the temporal stability of their response to local and large scale climate variability.

International audience; The oxygen isotope composition of human phosphatic tissues (delta18OP) has great potential for reconstructing climate and population migration, but this technique has not been applied to early human evolution. To facilitate this application we analyzed delta18OP values of modern human teeth collected at 12 sites located at latitudes ranging from 4 degrees N to 70 degrees N together with the corresponding oxygen composition of tap waters (delta18OW) from these areas. In addition, the delta18O of some raw and boiled foods were determined and simple mass balance calculations were performed to investigate the impact of solid food consumption on the oxygen isotope composition of the total ingested water (drinking water+solid food water). The results, along with those from three, smaller published data sets, can be considered as random estimates of a unique delta18OW/delta18OP linear relationship: delta18OW=1.54(+/-0.09)xdelta18OP-33.72(+/-1.51)(R2=0.87: p [H0:R2=0]=2x10(-19)). The delta18O of cooked food is higher than that of the drinking water. As a consequence, in a modern diet the delta18O of ingested water is +1.05 to 1.2 per thousand higher than that of drinking water in the area. In meat-dominated and cereal-free diets, which may have been the diets of some of our early ancestors, the shift is a little higher and the application of the regression equation would slightly overestimate delta18OW in these cases.

The reconstruction of droughts is essential for the understanding of past drought dynamics, and can help evaluate future drought scenarios in a changing climate. This article presents a reconstruction of summer droughts in France based on annually resolved, absolutely dated chronologies of oxygen isotope ratios (δ18O) in tree ring cellulose from Quercus spp. Samples were taken from living trees and timber wood from historic buildings at two sites: Fontainebleau (48° 23' N, 2° 40' E; 1326–2000 AD) and Angoulême (45° 44' N, 0° 18' E; 1360–2004 AD). Cellulose δ18O from these sites proved to be a good proxy of summer climate, as the trees were sensitive to temperature and moisture availability. However, offsets in average δ18O values between tree cohorts necessitated a correction before joining them to the final chronologies. Using the corrected δ18O chronologies, we developed models based on linear regression to reconstruct drought, expressed by the standardized precipitation evapotranspiration index (SPEI). The significant correlations between the SPEI and cellulose δ18O (r &approx; −0.70), as well as the verification of the models by independent data support the validity of these reconstructions. At both sites, recent decades are characterized by increasing drought. Fontainebleau displays dominantly wetter conditions during earlier centuries, whereas the current drought intensity is not unprecedented in the Angoulême record. While the δ18O chronologies at the two studied sites are highly correlated during the 19th and 20th century, there is a significant decrease in the correlation coefficient between 1550 and 1800 AD, which indicates either a weaker climate sensitivity of the tree ring proxies during this period, or a more heterogeneous climate in the north and the south of France. Future studies of tree ring isotope networks might reveal if the seasonality and spatial patterns of past droughts can explain this decoupling.

Mid-IR laser sources are of great interest for many applications. One interesting way to reach such wavelengths is the frequency conversion using a nonlinear material. Thus, the crystal growth of AgGaS2 is presented in this paper. As often reported, it must be annealed to be as transparent as possible for optical applications. Nevertheless, traditional vacuum annealings are too much long and the mechanism occurring not so well understood. Here, a new method based on a combination of a static and a dynamic vacuum annealing is proposed as well as its mechanism. Thus, highly transparent AgGaS2 samples were obtained for further optical experiments.

The history shows that the words «technology » and «culture » have taken many varied meanings. Their analysis reveal ambiguities, hesitations, controverses… These difficulties, as well as the weight of the social arbitrary, are doubtless at the origin of obstacles that, to day still, the technological culture encounters in its social recognition stage. The presupposed thoughts being taken away, an objectived definition of the technological culture is proposed which discloses, with regard to its appropriation by individuals of our societies, an important social fact. Indeed, a rapid observation of our post-industrial societies – often named exactly «technological » -lets appear the technological culture in multiple manifestations., L’histoire montre que les termes «technologie » et «culture » ont pris chacun des acceptions nombreuses et variées. Leurs analyses révèlent des ambiguïtés, des hésitations, des controverses… Ces difficultés ainsi que le poids de l’arbitraire social sont, sans nul doute, à l’origine des obstacles que rencontre aujourd’hui encore, la culture technologique dans sa phase de reconnaissance sociale. Les présupposés étant levés, une définition objectivée de la culture technologique est envisagée qui décèle, en ce qui concerne son appropriation par les individus de nos sociétés, un «fait social » d’importance. En effet, une observation rapide de nos sociétés post-industrielles – fréquemment appelées «technologiques » , précisément – laisse apparaître la culture technologique dans de multiples manifestations., Daux-Garcia Chantal. La culture technologique. In: Spirale. Revue de recherches en éducation, n°26, 2000. Culture scientifique et culture technique à l’école, sous la direction de Joëlle Delattre. pp. 169-185.

High-resolution microfractography performed in combination with transmission electron microscopy shows that the mechanical behaviour of carbon fibre reinforced Al-based matrix composites is related to the presence of brittle interfacial phases. Attaining the required specifications in the unreinforced part of cast aluminium aeronautical components locally reinforced with a carbon preform necessitates the use of a highly alloyed Al-based matrix. Moreover, the precipitate hardening heat treatment appropriate to the unreinforced alloy must be applied to the whole component. The two composites M40J/A357 and M40J/Cpyr/A357 (pyrolytic carbon coated fibres), either as-cast or after the usual T6 heat treatment of the A357 alloy (16 h solution treatment at 540°C followed by water quenching and 6 h ageing at 160°C) have been investigated. The formation of Si and Al4C3 interfacial brittle phases resulting from both the dendritic solidification and the solution treatment leads to the premature failure of the composite.

The evolution of the paleotemperatures of the Russian Platform over the Late Jurassic are inferred from stable isotope measurements on belemnite rostra. The δ 18O data indicate temperature variations ranging from 7 to 18 °C during the Oxfordian and a stable temperature cal 17 °C over Kimmeridgian and Volgian. The results are compared to data from the literature in the frame of the paleogeographic reconstruction of Europe for the Late Jurassic.

Eleven Icelandic hyaloclastites altered in freshwater have been studied. The weathering of basaltic glass, which is their primary constituent, leads to precipitation of clayey and possibly zeolitic phases. The dissolution reaction progress (mass of dissolved glass per liter of solution) governs the chemistry of the secondary phases, which control the residence time of the solution through their influence on rock permeability. They contribute to the regulation of reaction advancement. The reaction progress, ξ, can be calculated according to: ξ = [Srw·(Iw−Isp)·(IG + 9.375)][SrG·(ISP−IG)·(IW + 9.375)], where Iw, IG and ISP are the isotopic strontium ratios of initial water, of pristine glass, and secondary products, respectively, and SrW and SrG the strontium contents of initial water and glass. The amount of dissolved glass per liter of solution is estimated to be in the order of 0.01–0.1 g for samples 90000–100000 years old. A global agreement is found between this result and estimations that can be made on the basis of thermodynamic modelling. Expressing the geochemical budget as a function of the reaction progress allows a look at the evolving aspect of the rock/water interaction: 1. (1) According to the budget calculated for the major elements, the rock undergoes a global loss of matter which decreases with increasing reaction progress (from −45 to about 0% losses). For the most evolved samples, the transformation of the pristine basaltic glass to the alteration products is a nearly conservative process. 2. (2) There is increasing evidence that rare earth elements, particularly LREEs, can be mobilized during alteration processes. Our study corroborates this view as we demonstrate that REEs can be significantly mobilized during basaltic glass weathering. Nevertheless, no fractionation among the suite of REEs was observed. We show that Th and REE behaviours are similar. Mass balance calculations account for Th and REE losses up to 40%. These losses are not related to the reaction progress but could be due to a colloidal or particulate transport. The REE contents of the secondary clayey phases is showed to be linked to their degree of crystallinity. The need to take into account the latter parameter to modelize the long-term behaviour of the elements adsorbed onto clay minerals is outlined.