Sainte-Croix-En-Plaine – Zone d'activité II, lieu-dit Holzackerfeld

Identifiant de l'opération archéologique : Date de l'opération : 2001 (EV) À la suite du projet d'aménagement de la seconde phase de la zone d'activités économiques de Sainte-Croix-en-Plaine par le SISCO (Syndicat Intercommunal de la Plaine d'activités de Sainte-Croix-en-Plaine - Colmar), des fouilles d'évaluation ont été réalisées sur une surface de 86708 m² sur des terrains actuellement réservés à la culture. Une partie du site a été détruit récemment (1992-1994) lors de l'aménagement ..

Numerical Modeling of Microstructure Formation during Solidification and Heat Treatments of Ni-base superalloys

International audienceNumerical models have been developed for the simulation of microstructure formation in Ni-base alloys. The first step consists of a calculation of the segregation of solutal species in the primary solidified g-phase and formation/dissolution of the interdendritic g'-phase. Finally, local compositions of solutal species are used to calculate the nucleation, growth and coarsening of g'-precipitates with a precipitation model

The ecology, subsistence and diet of ~45,000-year-old Homo sapiens at Ilsenhöhle in Ranis, Germany

Recent excavations at Ranis (Germany) identified an early dispersal of Homo sapiens into the higher latitudes of Europe by 45,000 years ago. Here we integrate results from zooarchaeology, palaeoproteomics, sediment DNA and stable isotopes to characterize the ecology, subsistence and diet of these early H. sapiens. We assessed all bone remains (n = 1,754) from the 2016-2022 excavations through morphology (n = 1,218) or palaeoproteomics (zooarchaeology by mass spectrometry (n = 536) and species by proteome investigation (n = 212)). Dominant taxa include reindeer, cave bear, woolly rhinoceros and horse, indicating cold climatic conditions. Numerous carnivore modifications, alongside sparse cut-marked and burnt bones, illustrate a predominant use of the site by hibernating cave bears and denning hyaenas, coupled with a fluctuating human presence. Faunal diversity and high carnivore input were further supported by ancient mammalian DNA recovered from 26 sediment samples. Bulk collagen carbon and nitrogen stable isotope data from 52 animal and 10 human remains confirm a cold steppe/tundra setting and indicate a homogenous human diet based on large terrestrial mammals. This lower-density archaeological signature matches other Lincombian-Ranisian-Jerzmanowician sites and is best explained by expedient visits of short duration by small, mobile groups of pioneer H. sapiens. [Abstract copyright: © 2024. The Author(s).

Stable isotopes show Homo sapiens dispersed into cold steppes ~45,000 years ago at Ilsenhöhle in Ranis, Germany

The spread of Homo sapiens into new habitats across Eurasia ~45,000 years ago and the concurrent disappearance of Neanderthals represents a critical evolutionary turnover in our species' history. 'Transitional' technocomplexes, such as the Lincombian-Ranisian-Jerzmanowician (LRJ), characterize the European record during this period but their makers and evolutionary significance have long remained unclear. New evidence from Ilsenhöhle in Ranis, Germany, now provides a secure connection of the LRJ to H. sapiens remains dated to ~45,000 years ago, making it one of the earliest forays of our species to central Europe. Using many stable isotope records of climate produced from 16 serially sampled equid teeth spanning ~12,500 years of LRJ and Upper Palaeolithic human occupation at Ranis, we review the ability of early humans to adapt to different climate and habitat conditions. Results show that cold climates prevailed across LRJ occupations, with a temperature decrease culminating in a pronounced cold excursion at ~45,000-43,000 cal BP. Directly dated H. sapiens remains confirm that humans used the site even during this very cold phase. Together with recent evidence from the Initial Upper Palaeolithic, this demonstrates that humans operated in severe cold conditions during many distinct early dispersals into Europe and suggests pronounced adaptability. [Abstract copyright: © 2024. The Author(s).

Homo sapiens reached the higher latitudes of Europe by 45,000 years ago

The Middle to Upper Palaeolithic transition in Europe is associated with the regional disappearance of Neanderthals and the spread of Homo sapiens. Late Neanderthals persisted in western Europe several millennia after the occurrence of H. sapiens in eastern Europe1. Local hybridization between the two groups occurred2, but not on all occasions3. Archaeological evidence also indicates the presence of several technocomplexes during this transition, complicating our understanding and the association of behavioural adaptations with specific hominin groups4. One such technocomplex for which the makers are unknown is the Lincombian–Ranisian–Jerzmanowician (LRJ), which has been described in northwestern and central Europe5,6,7,8. Here we present the morphological and proteomic taxonomic identification, mitochondrial DNA analysis and direct radiocarbon dating of human remains directly associated with an LRJ assemblage at the site Ilsenhöhle in Ranis (Germany). These human remains are among the earliest directly dated Upper Palaeolithic H. sapiens remains in Eurasia. We show that early H. sapiens associated with the LRJ were present in central and northwestern Europe long before the extinction of late Neanderthals in southwestern Europe. Our results strengthen the notion of a patchwork of distinct human populations and technocomplexes present in Europe during this transitional period

Prevalence of Age-Related Macular Degeneration in Europe: The Past and the Future

Purpose Age-related macular degeneration (AMD) is a frequent, complex disorder in elderly of European ancestry. Risk profiles and treatment options have changed considerably over the years, which may have affected disease prevalence and outcome. We determined the prevalence of early and late AMD in Europe from 1990 to 2013 using the European Eye Epidemiology (E3) consortium, and made projections for the future. Design Meta-analysis of prevalence data. Participants A total of 42 080 individuals 40 years of age and older participating in 14 population-based cohorts from 10 countries in Europe. Methods AMD was diagnosed based on fundus photographs using the Rotterdam Classification. Prevalence of early and late AMD was calculated using random-effects meta-analysis stratified for age, birth cohort, gender, geographic region, and time period of the study. Best-corrected visual acuity (BCVA) was compared between late AMD subtypes; geographic atrophy (GA) and choroidal neovascularization (CNV). Main Outcome Measures Prevalence of early and late AMD, BCVA, and number of AMD cases. Results Prevalence of early AMD increased from 3.5% (95% confidence interval [CI] 2.1%–5.0%) in those aged 55–59 years to 17.6% (95%

Numerical simulation of AM1 microstructure

International audienceA modelling approach is developed for the description of microstructure formation in the industrial AM1 Ni-base superalloy. Solidification and homogenization simulations are first carried out using a microsegregation model, before using the local compositions as an input for precipitation calculations, in order to characterize the influence of segregation on precipitation. First, the precipitation model was validated by comparing simulated and measured evolutions of the average precipitate radius during isothermal heat treatments at 1100 °C and 1210 °C. The chained microsegregation and precipitation simulations indicate that the global sequences of precipitation events remains are qualitatively the same at the different locations in the microstructure, but the growth and dissolution kinetics are strongly influenced by the local compositions. Local supersaturations have a larger effect on the average radius of the precipitates than certain stages of the precipitation heat treatment

Numerical simulation of microstructure formation during solidification and heat treatments of Ni-base superalloys

International audienceA comprehensive modelling approach has been developed for the simulation of microstructure formation during solidification and heat treatment in Ni-base superalloys. The microsegregation taking place during solidification is simulated using the pseudo-front tracking (PFT) technique. This finite volume method calculates the concentration profiles in primary γ and the proportion of liquid and γ′ in the interdendritic regions. The same model is then used to describe the dissolution of the interdendritic γ′ particles during the subsequent solution heat treatment. The concentrations in primary γ predicted with the PFT model are then used to calculate the evolution of the γ′ precipitates and their size distributions at different locations in a dendrite arm during heat treatment. This is achieved with a precipitate size distribution (PSD) model. The classes of the distribution are created and tracked based on classical nucleation theory and a semi-analytical model for the growth of the precipitates as a function of their radius and the matrix supersaturation. The PFT and PSD models are both coupled with Thermo-Calc, which is used for the computation of the concentrations at the γ/liquid and γ/γ′ interfaces, for the Gibbs-Thomson effect in precipitates, and to calculate non-diagonal diffusion matrices based on a mobility database. The precipitation model was applied to a Ni-Al-Cr alloy and the results were compared with experimental data from the literature. Experimental and simulation results are in good qualitative agreement. The main phenomena taking place during precipitation, i.e. nucleation, growth and coarsening, are well reproduced by the precipitation model. Some discrepancies were observed on the precipitate number density, which were attributed to the homogeneous nucleation model. The full modelling sequence was then applied to Ni-Al in order to assess the influence of an incomplete homogenization heat treatment on the formation of γ′ precipitates

Numerical simulation of precipitation in multicomponent Ni-base alloys

International audienceA comprehensive particle size distribution model has been developed for the simulation of γ′ precipitation in multicomponent Ni alloys. Nucleation, growth and coarsening of the precipitates are described by a particle size distribution. The growth rate of each precipitate class is calculated with a multi-component diffusion model formulated for non-diagonal matrices of diffusion coefficients. The model is fully coupled with CALPHAD calculations of the thermodynamic equilibrium at the interface, including a direct treatment of the effect of curvature through modification of the Gibbs free energy. An optimization strategy was developed to minimize the computational cost. The model was used to simulate ageing heat treatment at 600 °C of Ni-7.56 at.% Al-8.56 at.% Cr, which was studied experimentally by Booth-Morrison and others (Booth-Morrison C, Weninger J, Sudbrack CK, Mao Z, Noebe RD, Seidman DN. Acta Mater 2008;56:3422; Mao Z, Booth-Morrison C, Sudbrack CK, Martin G, Seidman DN. Acta Mater 2012;60:1871). The comparisons showed that the precipitation stages of γ′ precipitates are correctly captured by the numerical model. It was shown that non-diagonal diffusion coefficients substantially influence the selection of the operating tie-line and the overall transformation kinetics. With non-diagonal diffusion matrices, complex phenomena such as uphill diffusion of Cr due to the Al gradients were evidenced and explained