Sr 2 IrO 4 magnetic phase diagram, from resistivity

International audienceWe show that the transition to the antiferromagnetic state in zero magnetic field does show up in the transverse resistivity, for which we point out the possibility for a direct spin orientation effect. In an applied field, we propose that the transition is split into two lines, corresponding to in-plane and out-of-plane magnetic ordering. This picture is corroborated by transverse magnetization measurements. The magnetic phase diagram for Sr2IrO4 was investigated, using the angular dependence of the resistivity transverse to the IrO2 planes

Evolution of habitat and environment of red deer (Cervus elaphus) during the Lateglacial and early Holocene in eastern France using stable isotope composition ( d13C, d15N, d18O) of archaeological bones.

International audienceRed deer (Cervus elaphus) is a flexible species that survived the significant climatic and environmental change toward warming temperature and forested landscape of the Late-glacial to early Holocene transition (ca. 17–6 ka cal BP). To investigate the conditions of ethological adaptation of red deer at that time, isotopic analysis of carbon, nitrogen, sulfur in collagen (δ13Ccoll, δ15Ncoll, δ34Scoll) and of oxygen in phosphate (δ18Op) were performed on red deer from archaeological sites of the French Jura and the western Alps. Fifty out of eighty two samples benefited from direct AMS radiocarbon dating, which confirmed the few number of red deer record during the cold Younger Dryas oscillation (ca. 12.8–11.6 ka cal BP) in Western Europe. The French Jura red deer showed a significant decrease in their δ13Ccoll values and increase in their δ15Ncoll values in the early Holocene compared to the Late-glacial, which is most likely due to the change in environment from open areas with low pedogenic activity to warm dense forests with increasing soil maturity. In contrast, the stable δ13Ccoll and δ15Ncoll values over time in the western Alps were thought to indicate a change to higher altitude for the red deer habitat in this mountainous region. A decrease of the δ18Op values between the Late-glacial and the early Holocene was observed in the western Alps red deer, in contrast to the expected increase with rising temperature which was indeed confirmed for the French Jura red deer. The multi-isotope results pointed to open areas home range at higher altitude for the Alps red deer in the Holocene compared to the previous period. The similarity of the δ34Scoll patterns with those of the δ15Ncoll suggested the primarily influence of soil activity on the 34S abundances recorded by red deer in a purely terrestrial context. Red deer of the French Jura on one hand and of the western Alps on the other hand showed different adaptive response to the global warming of the early Holocene, with an ethological change in the first case and a change in home range in the second case

Isotopic insights on ecological interactions between humans and woolly mammoths during the Middle and Upper Palaeolithic in Europe

Carbon and nitrogen isotopic composition of bone collagen in woolly mammoths, coeval her- bivores and predators, as well as hominins, allow researchers to quantify the proportion of meat consumed by late Neanderthals and early mod- ern humans in Europe. The proportions of con- sumed mammoth meat were found to be very high for late Neanderthals in sites from western France and Belgium between 45 and 40 ka, and for early modern humans from Belgium, Czech Republic, Crimea and western Russia, between 40 and 30 ka. A possible contribution of fresh- water resources was excluded in Belgium and Crimea using a novel approach based on single compound amino acid nitrogen isotopes and confirmed that mammoth consumption was the source of the high nitrogen isotopic ratio of ancient hominins in these sites. The impact of mammoth hunting on the Late Pleistocene eco- systems could be detected by a shift of isotopic values of horses onto those found for mammoth, suggesting that horses could use part of the eco- logical niche of mammoth probably due to a decrease of the proboscidean population. More- over, isotopic tracking of predator diet suggests that the mammoth carcasses left by humans were also exploited by scavengers, such as fox, wol- verine and brown bear. Therefore, stable isotopic tracking is a very useful approach to decipher the trophic interaction between hominins and mammoths and their possible ecological conse- quences.The symposium and the volume "Human-elephant interactions: from past to present" were funded by the Volkswagen Foundation

Nano- and Microstructured Copper/Copper Oxide Composites on Laser-Induced Carbon for Enzyme-Free Glucose Sensors

Low-cost enzyme-free glucose sensors with partial flexibility adaptable for wearable Internet of Things devices that can be envisioned as personalized point-of-care devices were produced by electroplating copper on locally carbonized flexible meta-polyaramid (Nomex) sheets using laser radiation. Freestanding films were annealed in nitrogen and nitrogen/air working environments, leading to the formation of Cu microspheroids and CuO urchins dispersed on the substrate film. The aggregation mechanism, crystallographic properties, surface chemistry, and electrochemical properties of the films were studied using scanning electron microscopy, X-ray diffractometry, transmission electron microscopy, X-ray photoelectron spectroscopy, and cyclic voltammetry. Cu microspheroids and CuO urchins attained activity for glucose detection and showed improvement of amperometric sensitivity to 0.25 and 0.32 mA cm$^{–2}$ mM$^{–1}$, respectively. The CuO urchin film retained its chemical composition after amperometric testing, and, by rinsing, allowed multiple repetitions with reproducible results. This study opens the possibility for the fabrication of durable composite biosensors with tailored shape, capable of implementation in flexible carriers, and microfluidic systems

Thriving or surviving? The isotopic record of the Wrangel Island woolly mammoth population

The world's last population of woolly mammoths (Mammuthus primigenius) lived on Wrangel Island persisting well into the Holocene, going extinct at ca. 4000 cal BP. According to the frequency of 'radiocarbon dated mammoth remains from the island, the extinction appears fairly abrupt. This study investigates the ecology of the Wrangel Island mammoth population by means of carbon, nitrogen and sulfur isotope analyses. We report new isotope data on 77 radiocarbon dated mammoth specimens from Wrangel Island and Siberia, and evaluate them in relation to previously published isotope data for Pleistocene mammoths from Beringia and lower latitude Eurasia, and the other insular Holocene mammoth population from St. Paul Island. Contrary to prior suggestions of gradual habitat deterioration, the nitrogen isotope values of the Wrangel Island mammoths do not support a decline in forage quality/quantity, and are in fact very similar to their north Beringian forebears right to the end. However, compared to Siberian mammoths, those from Wrangel Island show a difference in their energy economy as judged by the carbon isotope values of structural carbonate, possibly representing a lower need of adaptive strategies for survival in extreme cold. Increased mid-Holocene weathering of rock formations in the central mountains is suggested by sulfur isotope values. Scenarios related to water quality problems stemming from increased weathering, and a possibility of a catastrophic starvation event as a cause of, or contributing factor in their demise are discussed. (C) 2019 The Authors. Published by Elsevier Ltd.Peer reviewe

Les derniers rennes de Dordogne

Dans le cadre d’une étude régionale sur les modalités chronologiques et environnementales de la disparition du Renne (Rangifer tarandus) et de l’expansion du Cerf (Cervus elaphus) et du Chevreuil (Capreolus capreolus), une série d’analyses isotopiques en isotopes stables (13C, 15N) et de datations 14C par SMA sur collagène a été réalisée sur des cervidés des sites du Tardiglaciaire du Moulin du Roc (Saint-Chamassy) et de La Gare de Couze (Lalinde) situés en Dordogne. Les résultats des datations directes confirment la cohabitation du Renne et du Chevreuil au cours du Tardiglaciaire. Des cerfs datés des couches du Magdalénien supérieur de La Gare de Couze et du Magdalénien final du Moulin du Roc s’avèrent contemporains de la fin du Dryas récent ou GS-1. De plus, la couche brune-bigarrée du Moulin du Roc a livré un reste de Renne daté de 11860 ± 60 ans BP (13480-13860 ans cal BP, GrA-44537) qui situe ce spécimen au début de l’Alleröd ou GI-1c. Cette donnée confirme la présence du Renne en Dordogne après 12000 ans BP (ca. 13800 ans cal BP), alors que cette espèce semble avoir déjà disparu dans la région montagneuse des Pyrénées françaises et de la plaine septentrionale du Bassin parisien. Les teneurs en 13C des rennes de Dordogne montrent une légère diminution attribuable à la baisse de la disponibilité du lichen probablement liée au réchauffement climatique du début du Bölling. Cette tendance ne semble pas se confirmer avec le Renne de l’Alleröd du Moulin du Roc dont les teneurs isotopiques sont semblables à celles de ses congénères du Dryas ancien. Par ailleurs, les rennes du sud-ouest de la France présentent une teneur moyenne en 15N plus élevée que celles des rennes du Poitou, du Bassin parisien et des Alpes du Nord et Jura entre 12100 et 13400 ans BP (ca. 14000-16600 ans cal BP). Ce résultat pourrait refléter la reprise plus précoce de la pédogénèse dans le territoire du sud-ouest qui n’a pas subi la proximité d’un front glaciaire ou l’emprise directe d’un permafrost continu au cours du Dernier Maximum Glaciaire, à la différence des régions du Bassin parisien et du Jura. Les derniers rennes de Dordogne ont ainsi persisté au-delà de 12 000 ans BP dans un milieu où la production végétale s’était déjà intensifiée, permettant la coexistence de différentes espèces de cervidés. Nous présentons l’hypothèse qu’il pourrait s’agir d’une adaptation temporaire aux changements climatiques de l’interstade du Tardiglaciaire par des rennes sédentaires dans le sud-ouest de la France, tandis que les groupes plus mobiles des régions septentrionales ont changé leurs aires de répartition en modifiant leur schéma de déplacement

Ordering in a spin glass under applied magnetic field

Torque, torque relaxation, and magnetization measurements on a AuFe spin glass sample are reported. The experiments carried out up to 7 T show a transverse irreversibility line in the (H,T) plane up to high applied fields, and a distinct strong longitudinal irreversibility line at lower fields. The data demonstrate for that this type of sample, a Heisenberg spin glass with moderately strong anisotropy, the spin glass ordered state survives under high applied fields in contrast to predictions of certain "droplet" type scaling models. The overall phase diagram closely ressembles those of mean field or chiral models, which both have replica symmetry breaking transitions.Comment: 4 pages, 3 figures, accepted for PR

Alimentation humaine au cours du Magdalénien en Gironde d’après les teneurs en isotopes stables (13C, 15N) du collagène

Nous proposons une étude de l’alimentation humaine au cours du Magdalénien en Gironde qui intègre les derniers développements méthodologiques des reconstitutions basées sur les teneurs en isotopes stables (13C, 15N) du collagène. Lors d’un précédent travail (Drucker et Henry-Gambier 2005), la reconstitution isotopique du régime alimentaire de la femme de Saint-Germain-la-Rivière (Gironde) a bénéficié de l’application d’un modèle mathématique d’équation de mélange linéaire (Phillips et Koch 2002) adapté aux contraintes d’un contexte ancien. Une quantification des sources protéiques de l’alimentation a ainsi été rendue possible. Il en ressort que la femme de Saint-Germain-la-Rivière consommait surtout de la viande d’herbivores terrestres, majoritairement de Boviné. Dans cette étude, nous avons considéré d’autres sujets humains du Magdalénien de Gironde provenant des sites de Moulin-Neuf (Magdalénien moyen) et de l’abri Faustin (Magdalénien supérieur final). L’alimentation protéique de l’individu de Moulin-Neuf paraît essentiellement tournée vers les herbivores terrestres et plus spécifiquement le Cheval. Toutefois, dans le contexte de ce site, une certaine prudence s’impose par rapport à l’attribution de ce fossile humain au Paléolithique supérieur en l’absence actuelle de datation directe. L’individu magdalénien supérieur final de l’abri Faustin s’avère très significativement dépendant des ressources aquatiques avec une part plus importante des Cyprinidés par rapport au Saumon. Les teneurs en 15C et en 15N du collagène de vestiges humains Creswellien du Sud de l’Angleterre (Richards et al. 2000) n’indiquent pas une telle contribution des ressources d’eau douce dans leur alimentation. En comparaison avec les données de l’abri Faustin, l’alimentation humaine au Bölling/Alleröd en Angleterre reste inféodée aux ressources terrestres dans un contexte environnemental de toundra plus marqué que dans le Sud-Ouest de la France.We present a study of the human diet during the Magdalenian in Gironde which uses last methodological approaches of reconstruction based on collagen stable isotopes (13C, 15N). In Drucker and Henry-Gambier (2005), a linear mixing model (Phillips et Koch 2002) was applied taking into account constraints of ancient contexts. Quantification of diet protein sources was thus performed. The woman of Saint-Germain-la-Rivière appeared to consume essentially the meat of terrestrial herbivores, especially from large Bovid. In this paper, we considered other human individuals from the Magdalenian of Gironde from Moulin-Neuf (Middle Magdalenian) and abri Faustin (Final Magdalenian). The proteic part of the diet of Moulin-Neuf specimen seems to be essentially based on terrestrial herbivores and specifically Horse. However, in this site, the attribution of the human fossil to the Upper Palaeolithic period is not secured as there is no direct datation. The diet of the individual from the Final Magdalenian of abri Faustin includes a significant proportion of aquatic sources, with more Cyprinids than Salmon. The 13C and 15N amounts of collagen from Creswellian human remains from southern England (Richards et al. 2000) do not indicate a significant input of freshwater ressources in their diet. In comparison with the data of abri Faustin, the human diet during the Bölling/Alleröd in England depends on terrestrial ressources in a more toundric environment than in southwestern France

Nouvelles données chronologiques sur l’enfant de la grotte de Fauroux (Lugasson, Gironde)

La grotte de Fauroux a fourni deux ensembles stratigraphiques attribuables au Magdalénien et à l’Azilien. Des vestiges humains d’un adulte et d’un jeune enfant ont été découverts dans l’un des niveaux de l’Azilien et ont ainsi été attribués à cette culture. Cependant, une confirmation de cette attribution par une datation directe semblait nécessaire au vu des perturbations subies par le site suite à des effondrements et de la présence d’éléments post-paléolithiques. Le fémur gauche de l’individu immature a été retenu et a livré une date de 5035 ± 30 ans BP (GrA-38080, 3948 – 3761 ans av. J.-C.) qui place finalement ce vestige dans la période du Néolithique.The cave of Fauroux yielded two stratigraphical units attributed to Magdalenian and Azilian culture. Human remains of an adult and a very young child were discovered in association with the Azilian layer and, thus, were attributed to this culture. However, the confirmation of this chronological attributation was needed since the site was disturbed by several collapses and contained post-palaeolithic elements. The left femur from the immature individual was chosen and gave a date of 5035±30 years BP (GrA-38080, 3948 - 3761 years BC), which places this remain in the Neolithic period

Publisher Correction: Peripheral and central immune system crosstalk in Alzheimer disease — a research prospectus (Nature Reviews Neurology, (2021), 17, 11, (689-701), 10.1038/s41582-021-00549-x)

peer reviewedIn the originally published article, the first sentence of the Abstract erroneously included the word ‘that’ before the word ‘pathological’. The correct version reads as follows: “Dysregulation of the immune system is a cardinal feature of Alzheimer disease (AD), and a considerable body of evidence indicates pathological alterations in central and peripheral immune responses that change over time.” In addition, during manuscript preparation, a key reference (Da Mesquita, S., Fu, Z. & Kipnis, J. The meningeal lymphatic system: a new player in neurophysiology. Neuron 100, 375–388 (2018)) was inadvertently omitted from the section entitled The role of adaptive immunity and the lymphatic–glymphatic system. The reference has now been added. These corrections have both been made in the HTML and PDF versions of the paper