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High genetic variation and extensive gene flow may help forest trees with adapting to ongoing climate change, yet the genetic bases underlying their adaptive potential remain largely unknown. We investigated range-wide patterns of potentially adaptive genetic variation in 64 populations of European beech (Fagus sylvatica L.) using 270 SNPs from 139 candidate genes involved either in phenology or in stress responses. We inferred neutral genetic structure and processes (drift and gene flow) and performed differentiation outlier analyses and gene-environment association (GEA) analyses to detect signatures of divergent selection.Beech range-wide genetic structure was consistent with the species’ previously identified postglacial expansion scenario and recolonization routes. Populations showed high diversity and low differentiation along the major expansion routes. A total of 52 loci were found to be putatively under selection and 15 of them turned up in multiple GEA analyses. Temperature and precipitation related variables were equally represented in significant genotype-climate associations. Signatures of divergent selection were detected in the same proportion for stress response and phenology-related genes. The range-wide adaptive genetic structure of beech appears highly integrated, suggesting a balanced contribution of phenology and stress-related genes to local adaptation, and of temperature and precipitation regimes to genetic clines. Our results imply a best-case scenario for the maintenance of high genetic diversity during range shifts in beech (and putatively other forest trees) with a combination of gene flow maintaining within-population neutral diversity and selection maintaining between-population adaptive differentiation.

Side-chain-constrained amino acids are useful tools to modulate the biological properties of peptides. In this study, we applied side-chain constraints to apelin-13 (Ape13) by substituting the Pro12 and Phe13 positions, affecting the binding affinity and signaling profile on the apelin receptor (APJ). The residues 1Nal, Trp, and Aia were found to be beneficial substitutions for Pro12, and the resulting analogues displayed high affinity for APJ (Ki 0.08-0.18 nM vs Ape13 Ki 0.7 nM). Besides, constrained (d-Tic) or α,α-disubstituted residues (Dbzg; d-α-Me-Tyr(OBn)) were favorable for the Phe13 position. Compounds 47 (Pro12-Phe13 replaced by Aia-Phe, Ki 0.08 nM) and 53 (Pro12-Phe13 replaced by 1Nal-Dbzg, Ki 0.08 nM) are the most potent Ape13 analogues activating the Gα12 pathways (53, EC50 Gα12 2.8 nM vs Ape13, EC50 43 nM) known to date, displaying high affinity, resistance to ACE2 cleavage as well as improved pharmacokinetics in vitro (t1/2 5.8-7.3 h in rat plasma) and in vivo.

Targeted proteomics allows the highly sensitive detection of specific peptides and proteins in complex biological samples. Here, we describe a methodology for targeted peptide quantification using a trapped ion mobility quadrupole time-of-flight mass spectrometer (timsTOF Pro). The prm-PASEF method exploits the multiplexing capability provided by the trapped ion mobility separation, allowing more than 200 peptides to be monitored over a 30 min liquid chromatography separation. Compared to conventional parallel reaction monitoring (PRM), precursor ions are accumulated in the trapped ion mobility spectrometry (TIMS) cells and separated according to their shape and charge before eluting into the quadrupole time-of-flight (QTOF) part of the mass spectrometer. The ion mobility trap allows measuring up to six peptides from a single 100 ms ion mobility separation with the current setup. Using these improved mass spectrometric capabilities, we detected and quantified 216 isotope-labeled synthetic peptides (AQUA peptides) spiked in HeLa human cell extract with limits of quantification of 17.2 amol for some peptides. The acquisition method is highly reproducible between injections and enables accurate quantification in biological samples, as demonstrated by quantifying KRas, NRas, and HRas as well as several Ras mutations in lung and colon cancer cell lines on fast 10 min gradient separations.

Identification of a common Diels-Alder pattern in three classes of bioactive natural products led us to study the synthesis and cycloaddition of a new class of cyclic dienes readily available from β,γ-unsaturated lactams. A practical and readily scalable route to the parent p-methoxybenzyl-protected 6- and 7-membered β,γ-unsaturated lactams was developed. These were readily transformed into the corresponding O-silylated dienes, which were reacted with dimethyl and diethyl fumarate to yield stereoselectively highly functionalized bicyclic adducts. These exhibited unexpected and versatile transformations upon acid hydrolysis depending on the nature of the dienophile substituents and the acid catalyst. All reactions have been performed on multigram quantities. These transformations provide a convenient, economical, and easily scalable pathway for the rapid construction of functionally and stereochemically dense privileged scaffolds for the construction of libraries of natural products-inspired molecules of pharmacological relevance.

Dendi Lake Rockshelter is situated about 100 km west of Addis Ababa on the west-central part of the Ethiopian Plateau in the Ginchi woreda of Ethiopia’s Oromiya regional state. In October 2012, a t...

In the course of evolution, pecorans (i.e., higher ruminants) developed a remarkable diversity of osseous cranial appendages, collectively referred to as “headgear,” which likely share the same origin and genetic basis. However, the nature and function of the genetic determinants underlying their number and position remain elusive. Jacob and other rare populations of sheep and goats are characterized by polyceraty, the presence of more than two horns. Here, we characterize distinct POLYCERATE alleles in each species, both associated with defective HOXD1 function. We show that haploinsufficiency at this locus results in the splitting of horn bud primordia, likely following the abnormal extension of an initial morphogenetic field. These results highlight the key role played by this gene in headgear patterning and illustrate the evolutionary co-option of a gene involved in the early development of bilateria to properly fix the position and number of these distinctive organs of Bovidae.

Each International Geomagnetic Reference Field (IGRF) model released under the auspices of the International Association of Geomagnetism and Aeronomy comprises a secular variation component that describes the evolution of the main magnetic field anticipated for the 5 years to come. Every Gauss coefficient, up to spherical harmonic degree and order 8, is assumed to undergo its own independent linear evolution. With a mathematical model of the core magnetic field and its time rate of change constructed from geomagnetic observations at hand, a standard prediction of the secular variation (SV) consists of taking the time rate of change of each Gauss coefficient at the final time of analysis as the predicted rate of change. The last three generations of the IGRF have additionally witnessed a growing number of candidate SV models relying upon physics-based forecasts. This surge is motivated by satellite data that now span more than two decades and by the concurrent progress in the numerical modelling of Earth’s core dynamics. Satellite data reveal rapid (interannual) geomagnetic features whose imprint can be detrimental to the quality of the IGRF prediction. This calls for forecasting frameworks able to incorporate at least part of the processes responsible for short-term geomagnetic variations. In this letter, we perform a retrospective analysis of the performance of past IGRF SV models and candidates over the past 35 years; we emphasize that over the satellite era, the quality of the 5-year forecasts worsens at times of rapid geomagnetic changes. After the definition of the time scales that are relevant for the IGRF prediction exercise, we cover the strategies followed by past physics-based candidates, which we categorize into a “‘core–surface flow” family and a “dynamo” family, noting that both strategies resort to “input” models of the main field and its secular variation constructed from observations. We next review practical lessons learned from our previous attempts. Finally, we discuss possible improvements on the current state of affairs in two directions: the feasibility of incorporating rapid physical processes into the analysis on the one hand, and the accuracy and quantification of the uncertainty impacting input models on the other hand.

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International audience; The casein micelle (CM) have been described as a protein assembly held together by interactions between phosphoryl groups from the protein moieties, and several internal calcium phosphate nanoclusters (CCPs). While the presence of protein inhomogeneities at the small scale, sequestering the CCPs, has been widely accepted, the presence of medium scale inhomogeneities, the so-called "Hard" regions, and its relationship with the CCPs, has been object of debate. In the present work, solid state NMR and SAXS data have been combined to study the correlation between the removal of CCPs and the structural modification of the micelle. A << native >> sample and three different demineralized ones; 5% (DM-05), 10% (DM-10), and 25% (DM-25) of calcium in relation with the "native", have been analyzed. NMR data show that the reduction in the total amount of calcium and phosphorous ions (-5%, -10% and -25% respectively) in the samples is not always equivalent to the loss of CCPs as measured by the decrease of the amount of colloidal P-31 (-15 and -17% and -25% respectively) in the samples. NMR data also indicate, that demineralization induces the total depletion of some CCP while leaving the remaining cluster in a rather "native" like structure. SAXS data show a good correlation between the amount of P-31 loss measured by NMR and the decreases in intensity for the SAXS spectral features associated with the nanoclusters. Finally, SAXS data show the demineralization induces a decrease in the amount of the larger inhomogeneities in the micelle (the so called "Hard" regions). However, this decrease is not directly correlated to the decrease in the amount of CCPs (as measured by SAXS and NMR) indicating that these "Hard" regions may be, at least partially, maintained by a large protein-protein interaction network. The data and results are discussed and compared with different structural models of casein micelle.

Gravitational instability (GI) controls the dynamics of young massive protoplanetary discs. Apart from facilitating gas accretion on to the central protostar, it must also impact on the process of planet formation: directly through fragmentation, and indirectly through the turbulent concentration of small solids. To understand the latter process, it is essential to determine the dust dynamics in such a turbulent flow. For that purpose, we conduct a series of 3D shearing box simulations of coupled gas and dust, including the gas's self-gravity and scanning a range of Stokes numbers, from 0.001 to ~0.2. First, we show that the vertical settling of dust in the midplane is significantly impeded by gravitoturbulence, with the dust scale-height roughly 0.6 times the gas scale height for centimetre grains. This is a result of the strong vertical diffusion issuing from (a) small-scale inertial-wave turbulence feeding off the GI spiral waves and (b) the larger-scale vertical circulations that naturally accompany the spirals. Second, we show that at R=50 AU concentration events involving sub-metre particles and yielding order 1 dust to gas ratios are rare and last for less than an orbit. Moreover, dust concentration is less efficient in 3D than in 2D simulations. We conclude that GI is not especially prone to the turbulent accumulation of dust grains. Finally, the large dust scale-height measured in simulations could be, in the future, compared with that of edge-on discs seen by ALMA, thus aiding detection and characterisation of GI in real systems., Comment: Accepted in MNRAS, 13 pages

The pace of tree microevolution during Anthropocene warming is largely unknown. We used a retrospective approach to monitor genomic changes in oak trees since the Little Ice Age (LIA). Allelic frequency changes were assessed from whole-genome pooled sequences for four age-structured cohorts of sessile oak (Quercus petraea) dating back to 1680, in each of three different oak forests in France. The genetic covariances of allelic frequency changes increased between successive time periods, highlighting genome-wide effects of linked selection. We found imprints of convergent linked selection in the three forests during the late LIA, and a shift of selection during more recent time periods. The changes in allelic covariances within and between forests mirrored the documented changes in the occurrence of extreme events (droughts and frosts) over the last three hundred years. The genomic regions with the highest covariances were enriched in genes involved in plant responses to pathogens and abiotic stresses (temperature and drought). These responses are consistent with the reported sequence of frost (or drought) and disease damage ultimately leading to the oak dieback after extreme events. Our results therefore provide evidence of selection operating on long-lived species during recent climatic changes.

International audience; Three families of anionic sugar-based surfactants bearing a sulfate functional group on the primary position of a monosaccharide were synthesized and their physicochemical properties were compared. The first family corresponds to 6-sulfate derivatives of commercially available octa- and dodecyl β-d-gluco- and galactopyranosides. The second and the third families contain an amide linker between the sulfated monosaccharide (galactose, glucose or xylose) and the hydrophobic alkyl chain. Twelve of the as-synthesized anionic glycolipids, including nine novel sulfated compounds, were investigated for their surface activity at the air/liquid interface and for their self-assembling properties. These sugar-based surfactants show surface properties similar to those of commercial anionic surfactants (SDS and SLES) with good ability to reduce surface tension. The obtained results confirm the interest in these new bio-based molecules for potential substitution of anionic surfactants in various formulations.

Middle Stone Age humans in high-altitude Africa Recent archaeological research has produced evidence of the earliest human occupation of high-altitude habitats in the Andes and the Tibetan Plateau. Ossendorf et al. now present the oldest evidence of human settlement and adaptation to areas above 4000-meter elevation in Africa (see the Perspective by Aldenderfer). Their excavations at a rock shelter in the Bale Mountains of Ethiopia reveal obsidian artifacts and faunal remains, including abundant burnt bones, mostly of giant mole-rats. The findings reveal the environmental conditions and show how Late Pleistocene humans adapted to the harsh environments of these glaciated high-altitude African landscapes. Science , this issue p. 583 ; see also p. 541

Sulfated oligosaccharides are involved in important biological events that are often modulated by specific sequences and sulfation patterns, but their structural analysis remains challenging. Matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS) analysis of three different sulfated oligosaccharides (Fondaparinux, the octasulfated pentasaccharide, a disulfated heparin-derived tetrasaccharide 1, and an octasulfated maltoheptaose) 2 was performed using the 2-(4-hydroxyphenylazo)benzoic acid-tetramethylguanidinium (HABA-TMG2) matrix. High resolution mass spectrometry of the main ions observed was successful, and this was complemented by tandem mass spectrometry (MS/MS) analysis for structural assessment. Despite sulfate losses, fully sulfated molecular ions were observed and these allowed the determination of oligosaccharide structures: UA-GlcNAc-UA(2S)-AnhMan(6S) for compound 1 and (Glc6S)6-Glc (1S,6S) for compound 2.

Over three field seasons between 2007 and 2012, we excavated three caves—Mota, Tuwatey, and Gulo—situated at an average elevation of 2,084 m above sea level in the cool and moist Boreda Gamo Highlands of southwestern Ethiopia. Anthropogenic deposits in these caves date from the Middle to Late Holocene (ca. 6000 to 100 BP) and provide excellent preservation of material culture, fauna, flora, and human skeletal remains from which to investigate changes in technologies and habitat use over the last several thousand years. Here, we present results and interpretations, suggesting ways in which Holocene communities of the Boreda Gamo Highlands constructed new landscapes and technologies in their transition from hunting and gathering to an agropastoral way of life.

The radial transport of angular momentum in accretion disk is a fundamental process in the universe. It governs the dynamical evolution of accretion disks and has implications for various issues ranging from the formation of planets to the growth of supermassive black holes. While the importance of magnetic fields for this problem has long been demonstrated, the existence of a source of transport solely hydrodynamical in nature has proven more difficult to establish and to quantify. In recent years, a combination of results coming from experiments, theoretical work and numerical simulations has dramatically improved our understanding of hydrodynamically mediated angular momentum transport in accretion disk. Here, based on these recent developments, we review the hydrodynamical processes that might contribute to transporting angular momentum radially in accretion disks and highlight the many questions that are still to be answered., Comment: 23 pages, 4 figures, proceeding for the Astrofluid conference in honor of Jean-Paul Zahn (Paris, June 2016), references added

Herein, we report a convenient synthesis of unprecedented aza-diketopiperazines (aza-DKPs). The strategy is based on selective diversification of bicyclic aza-DKP scaffolds by click reaction, N-acylation, and/or N-alkylation. These scaffolds containing either azido or amino groups were obtained by a key Rh(I)-catalyzed hydroformylative cyclohydrocarbonylation reaction of allyl-substituted aza-DKP. The methodology is readily amenable to the parallel synthesis of original aza-DKPs to enlarge the chemical diversity of aza-heterocycles.

Protoplanetary discs are made of gas and dust orbiting a young star. They are also the birth place of planetary systems, which motivates a large amount of observational and theoretical research. In these lecture notes, I present a review of the magnetic mechanisms applied to the outer regions R>1 AU of these discs, which are the planet-formation regions. In contrast to usual astrophysical plasmas, the gas in these regions is noticeably cold (T, 115 pages, 46 figures, accepted for publication in the lecture notes series of the Journal of Plasma Physics (Cambridge University Press)

International audience; The EVOSHEEP project combines archaeozoology, geometric morphometrics and genetics to study archaeo- logical sheep assemblages dating from the sixth to the first millennia BC in eastern Africa, the Levant, the Ana- tolian South Caucasus, the Iranian Plateau and Mesopotamia. The project aims to understand changes in the physical appearance and phenotypic characteristics of sheep and how these related to the appearance of new breeds and the demand for secondary products to supply the textile industry.

In their early stages, protoplanetary discs are sufficiently massive to undergo gravitational instability (GI). This instability is thought to be involved in mass accretion, planet formation via gas fragmentation, the generation of spiral density waves, and outbursts. A key and very recent area of research is the interaction between the GI and magnetic fields in young protoplanetary discs, in particular whether this instability is able to sustain a magnetic field via a dynamo. We conduct three-dimensional, stratified shearing-box simulations using two independent codes, PLUTO and Athena++, to characterise the GI dynamo in poorly ionised protostellar discs subject to ambipolar diffusion. We find that the dynamo operates across a large range of ambipolar Elssaser number Am (which characterises the strength of ambipolar diffusion) and is particularly strong in the regime Am=10-100, with typical magnetic to thermal energy ratios of order unity. The dynamo is only weakly dependent on resolution (at least for Am, accepted in MNRAS

Earth, Planets and Space, 73 (1), ISSN:1343-8832, ISSN:1880-5981

This paper describes the design of a candidate secular variation model for the 13th generation of the International Geomagnetic Reference Field. This candidate is based upon the integration of an ensemble of 100 numerical models of the geodynamo between epochs 2019.0 and 2025.0. The only difference between each ensemble member lies in the initial condition that is used for the numerical integration, all other control parameters being fixed. An initial condition is defined as follows: an estimate of the magnetic field and its rate-of-change at the core surface for 2019.0 is obtained from a year (2018.5–2019.5) of vector Swarm data. This estimate (common to all ensemble members) is subject to prior constraints: the statistical properties of the numerical dynamo model for the main geomagnetic field and its secular variation, and prescribed covariances for the other sources. One next considers 100 three-dimensional core states (in terms of flow, buoyancy and magnetic fields) extracted at different discrete times from a dynamo simulation that is not constrained by observations, with the time distance between each state exceeding the dynamo decorrelation time. Each state is adjusted (in three dimensions) in order to take the estimate of the geomagnetic field and its rate-of-change for 2019.0 into account. This methodology provides 100 different initial conditions for subsequent numerical integration of the dynamo model up to epoch 2025.0. Focussing on the 2020.0–2025.0 time window, we use the median average rate-of-change of each Gauss coefficient of the ensemble and its statistics to define the geomagnetic secular variation over that time frame and its uncertainties.

ELABELA (ELA) is the second endogenous ligand of the apelin receptor (APJ). Although apelin-13 and ELA both target APJ, there is limited information on structure-activity relationship (SAR) of ELA. In the present work, we identified the shortest bioactive C-terminal fragment ELA23-32, which possesses high affinity for APJ (Ki 4.6 nM) and produces cardiorenal effects in vivo similar to those of ELA. SAR studies on conserved residues (Leu25, His26, Val29, Pro30, Phe31, Pro32) show that ELA and apelin-13 may interact differently with APJ. His26 and Val29 emerge as important for ELA binding. Docking and binding experiments suggest that Phe31 of ELA may bind to a tight groove distinct from that of Phe13 of Ape13, while the Phe13 pocket may be occupied by Pro32 of ELA. Further characterization of signaling profiles on the Gαi1, Gα12, and β-arrestin2 pathways reveals the importance of aromatic residue at the Phe31 or Pro32 position for receptor activation.

Superconducting links are an innovative solution for bulk power transmission, distinguished by their compact dimensions, high efficiency and small environmental footprint. As with any new technology field, there is a large amount of design possibilities for such links, each of them having a profound impact on the system configuration. For instance, changing the material can imply a change in the working temperature from 20 to 70 K and has consequences on the maximum link length. This article presents the dichotomic decision possibilities for the optimized design of a high-power superconducting link, focusing on some of the key components of the cable system. The complex design optimization process is exemplified using the European project Best Paths, in which the first 3-gigawatt-class superconducting cable system was designed, optimized, manufactured, and successfully tested.

Astrophysical disks are likely embedded in an ambient vertical magnetic field. This ambient field is known to drive magneto-rotational turbulence in the disk bulk but is also responsible for the launching of magnetized outflows at the origin of astrophysical jets. The vertical structure and long-term (secular) evolution of such a system lack quantitative predictions. It is nevertheless this secular evolution that is proposed to explain time variability in many accreting systems such as X-ray binaries. We compute and analyze global 3D ideal-MHD simulations of an accretion disk threaded by a large-scale magnetic field. We evaluate the role of the turbulent terms in the equilibrium of the system. We then compute the transport of mass, angular momentum, and magnetic fields in the disk to characterize its secular evolution. We perform a parameter survey to characterize the influence of disk properties on secular transport. We find that weakly magnetized disks drive jets that carry away a small fraction of the disk angular momentum. The mass-weighted accretion speed remains subsonic although, there is always an upper turbulent atmospheric region where transonic accretion takes place. We show that a strongly magnetized version of the magneto-rotational instability drives this turbulence. The disk structure is drastically different from the conventional hydrostatic picture. The magnetic field is always dragged inwards in the disk, at a velocity that increases with the disk magnetization. Beyond a threshold on the latter, the disk undergoes a profound radial readjustment. It leads to the formation of an inner accretion-ejection region with a supersonic mass-weighted accretion speed and where the magnetic field distribution becomes steady, near equipartition with the thermal pressure. This inner structure shares many properties with the Jet Emitting Disk model described by Ferreira (1997)., Paper accepted on A&A, November 30, 2020

In this work hyaluronic acid (HA) oligosaccharides with degree of polymerization (DP) 4, 6 and 8, obtained by enzymatic depolymerization of HA, were conjugated to a PEG-phospholipid moiety. The products (HA-DP4, HA-DP6 and HA-DP8) were used to prepare decorated liposomes. The cellular uptake of HA-DP4, HA-DP6 and HA-DP8-decorated fluorescently labelled liposomes was significantly higher (12 to 14-fold) in lung cancer cell lines with high CD44 expression than in those with low CD44 expression, suggesting a receptor-mediated entry of HA-conjugated formulations. Competition assays showed that the uptake followed this rank order: HA-DP8>HA-DP6>HA-DP4 liposomes. Moreover, they are capable of a faster interaction with CD44, followed by phagocytosis, than HA liposomes obtained from HA of higher molecular weight (4800 and 14800 Da). HA-DP4, HA-DP6 and HA-DP8-liposomes did not show cytotoxicity or inflammatory effects. Overall, we propose our new HA-DP oligosaccharides as biocompatible and effective tools for a potential drug delivery to CD44-positive cells.

We present a new model of the geomagnetic field spanning the last 20 years and called Kalmag. Deriving from the assimilation of CHAMP and Swarm vector field measurements, it separates the different contributions to the observable field through parameterized prior covariance matrices. To make the inverse problem numerically feasible, it has been sequentialized in time through the combination of a Kalman filter and a smoothing algorithm. The model provides reliable estimates of past, present and future mean fields and associated uncertainties. The version presented here is an update of our IGRF candidates; the amount of assimilated data has been doubled and the considered time window has been extended from [2000.5, 2019.74] to [2000.5, 2020.33]., German Research Foundation (DFG), Projekt DEAL

We analyze a sample of 12 HST-selected edge-on protoplanetary disks for which the vertical extent of the emission layers can be constrained directly. We present ALMA high angular resolution continuum images (0.1arcsec) of these disks at two wavelengths, 0.89mm and 2.06mm (respectively ALMA bands 7 and 4), supplemented with archival band 6 data (1.33mm) where available. For most sources, the millimeter continuum emission is more compact than the scattered light, both in the vertical and radial directions. Six sources are resolved along their minor axis in at least one millimeter band, providing direct information on the vertical distribution of the millimeter grains. For the second largest disk of the sample, the significant difference in vertical extent between band 7 and band 4 suggests efficient size-selective vertical settling of large grains. Furthermore, the only Class I object in our sample shows evidence of flaring in the millimeter. Along the major axis, all disks are well resolved. Four of them are larger in band 7 than in band 4 in the radial direction, and three have a similar radial extent in all bands. For all disks, we also derive the millimeter brightness temperature and spectral index maps. We find that the disks are likely optically thick and that the dust emission reveals low brightness temperatures in most cases (, Accepted for publication in Astronomy and Astrophysics Updates: Few typos in the text + Table A.1

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In this study, new approaches are developed for measuring and understanding the reactivity of East African amplifier lakes and the societies that occupied their margins to African monsoon related hydrological changes. Drawing on seven newly discovered archaeological sites in the Lower Awash valley, corresponding to the northern Abhe Lake basin, we present the first Holocene human occupation sequence in the Ethiopian Afar. We reconstitute fluctuating Abhe Lake levels in association with human settlement strategies through correlation of new archaeological and geomorphological data and 37 new radiocarbon dates. The sites cluster into three periods of human occupation of the lake margins separated by intervals that lack archaeological data. These occupation phases span two major humid-arid transitions of the African Humid Period (AHP) (including the Younger Dryas (YD, ∼12.9–11.7 ka), 8.2 ka, and 4.2 ka arid events) during which Abhe Lake levels varied significantly, and the transition from Later Stone Age (LSA) hunter-gatherers to mixed herding-hunter-gatherer economies. Over a 9000 year period we observe continuity and ruptures in subsistence strategies and material culture techno-complexes and correlate these with sedimentary formation processes and changing paleo-shorelines. Our study reveals that flexible multiple resource economies were a human response to strongly fluctuating environments, even with the onset of herding and associated pottery traditions unique to the Abhe Lake basin, sometime between 4.8 and 3.3 ka cal. BP. Thorough evaluation of littoral morpho-sedimentary data, well-dated human settlements and associated economic strategies suggests that major cultural and socio-economic changes of populations inhabiting Abhe paleolakeshores were distinctive ecological responses to transformations in the local environment and to fluctuating lake levels.

In December 2019, the 13th revision of the International Geomagnetic Reference Field (IGRF) was released by the International Association of Geomagnetism and Aeronomy (IAGA) Division V Working Group V-MOD. This revision comprises two new spherical harmonic main field models for epochs 2015.0 (DGRF-2015) and 2020.0 (IGRF-2020) and a model of the predicted secular variation for the interval 2020.0 to 2025.0 (SV-2020-2025). The models were produced from candidates submitted by fifteen international teams. These teams were led by the British Geological Survey (UK), China Earthquake Administration (China), Universidad Complutense de Madrid (Spain), University of Colorado Boulder (USA), Technical University of Denmark (Denmark), GFZ German Research Centre for Geosciences (Germany), Institut de physique du globe de Paris (France), Institut des Sciences de la Terre (France), Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation (Russia), Kyoto University (Japan), University of Leeds (UK), Max Planck Institute for Solar System Research (Germany), NASA Goddard Space Flight Center (USA), University of Potsdam (Germany), and Universit\'e de Strasbourg (France). The candidate models were evaluated individually and compared to all other candidates as well to the mean, median and a robust Huber-weighted model of all candidates. These analyses were used to identify, for example, the variation between the Gauss coefficients or the geographical regions where the candidate models strongly differed. The majority of candidates were sufficiently close that the differences can be explained primarily by individual modeling methodologies and data selection strategies. None of the candidates were so different as to warrant their exclusion from the final IGRF-13. The IAGA V-MOD task force thus voted for two approaches: the median of the Gauss coefficients of the candidates for the DGRF-2015 and IGRF-2020 models and the robust Huber-weighted model for the predictive SV-2020-2025. In this paper, we document the evaluation of the candidate models and provide details of the approach used to derive the final IGRF-13 products. We also perform a retrospective analysis of the IGRF-12 SV candidates over their performance period (2015-2020). Our findings suggest that forecasting secular variation can benefit from combining physics-based core modeling with satellite observations.

International audience; Most existing forests are subjected to natural and human-mediated selection pressures, which have increased due to climate change and the increasing needs of human societies for wood, fibre and fuel resources. It remains largely unknown how these pressures trigger evolutionary changes. We address this issue here for temperate European oaks (Quercus petraeaandQ. robur), which grow in mixed stands, under even-aged management regimes. We screened numerous functional traits for univariate selection gradients and for expected and observed genetic changes over two successive generations. In both species, growth, leaf morphology and physiology, and defence-related traits displayed significant selection gradients and predicted shifts, whereas phenology, water metabolism, structure and resilience-related traits did not. However, the direction of the selection response and the potential for adaptive evolution differed between the two species.Quercus petraeahad a much larger phenotypic and genetic variance of fitness thanQ. robur. This difference raises concerns about the adaptive response ofQ. roburto contemporary selection pressures. Our investigations suggest thatQ. roburwill probably decline steadily, particularly in mixed stands withQ. petraea, consistent with the contrasting demographic dynamics of the two species.

International audience; Isolating genetic markers is often costly and time-consuming for non-model fungal species. However, these markers are of primary importance to identify the origin of invasive species and to infer their reproductive mode and dispersal ability. We slightly modified a recent molecular method to quickly isolate and validate single-nucleotide polymorphism (SNP) markers, from a first Erysiphe alphitoides draft genome, one of the main causal agent of oak powdery mildew in Europe. Although the draft assembly was strongly fragmented (555,289 contigs), we successfully isolated 1700 SNPs from 75 single-copy genes conserved in most fungal genomes. Ninety percent of them allowed to clearly distinguish the two main Erysiphe species reported on European oaks: E. alphitoides and E. quercicola. Thirty-six SNPs, located in distinct genes, were then validated using a strategy of MassArray genotyping on 95 E. alphitoides isolates sampled in Europe. This genotyping showed that only monospore isolates had the expected haploid signature, whereas direct genotyping from field leaves showed signature of mixed infection. Considering haploid isolates, these markers led to the first results of population genetic diversity, and suggested that E. quercicola may have a more asexual reproduction than its sister species, E. alphitoides.

SummaryThe tree of life is highly reticulate, with the history of population divergence buried amongst phylogenies deriving from introgression and lineage sorting. In this study, we test the hypothesis that there are regions of the oak (Quercus, Fagaceae) genome that are broadly informative about phylogeny and investigate global patterns of oak diversity.We utilize fossil data and restriction-site associated DNA sequencing (RAD-seq) for 632 individuals representing ca. 250 oak species to infer a time-calibrated phylogeny of the world’s oaks. We use reversible-jump MCMC to reconstruct shifts in lineage diversification rates, accounting for among-clade sampling biases. We then map the > 20,000 RAD-seq loci back to a recently published oak genome and investigate genomic distribution of introgression and phylogenetic support across the phylogeny.Oak lineages have diversified among geographic regions, followed by ecological divergence within regions, in the Americas and Eurasia. Roughly 60% of oak diversity traces back to four clades that experienced increases in net diversification due to climatic transitions or ecological opportunity.The support we find for the phylogeny contrasts with high genomic heterogeneity in phylogenetic signal and introgression. Oaks are phylogenomic mosaics, and their diversity may in fact depend on the gene flow that shapes the oak genome.

Pectin oligosaccharides, which can be obtained from fruit wastes, have proven their potential as plant immune-system elicitors. Although the precise size of active species is still under investigation, medium size oligosaccharides have been reported as the most active. Three defined oligogalacturonic acid (OGAs) mixtures were produced from commercial pectin, orange peel and apple pomace residues. The methodology developed involves two sequential acid treatments followed by stepwise ethanol precipitation. Without the need of chromatographic separations, three different fractions were obtained. The fractions were analyzed by high performance anion exchange chromatography (HPAEC) and were completely characterized by mass spectrometry, showing that the small size, medium size and large size fractions contained OGAs of degree of polymerization 3 to 9, 6 to 18, and 16 to 55, respectively.

Large-scale vertical magnetic fields are believed to play a key role in the evolution of protoplanetary discs. Associated with non-ideal effects, such as ambipolar diffusion, they are known to launch a wind that could drive accretion in the outer part of the disc ($R> 1$ AU). They also potentially lead to self-organisation of the disc into large-scale axisymmetric structures, similar to the rings recently imaged by sub-millimetre or near-infrared instruments (ALMA and SPHERE). The aim of this paper is to investigate the mechanism behind the formation of these gaseous rings, but also to understand the dust dynamics and its emission in discs threaded by a large-scale magnetic field. To this end, we performed global magneto-hydrodynamics (MHD) axisymmetric simulations with ambipolar diffusion using a modified version of the PLUTO code. We explored different magnetisations with the midplane $\beta$ parameter ranging from $10^5$ to $10^3$ and included dust grains -- treated in the fluid approximation -- ranging from $100 \mu$m to 1 cm in size. We first show that the gaseous rings (associated with zonal flows) are tightly linked to the existence of MHD winds. Secondly, we find that millimetre-size dust is highly sedimented, with a typical scale height of 1 AU at $R=100$ AU for $\beta=10^4$, compatible with recent ALMA observations. We also show that these grains concentrate into pressure maxima associated with zonal flows, leading to the formation of dusty rings. Using the radiative transfer code MCFOST, we computed the dust emission and make predictions on the ring-gap contrast and the spectral index that one might observe with interferometers like ALMA., Comment: 17 pages, accepted in A&A

We describe a new, original approach to the modelling of the Earth’s magnetic field. The overall objective of this study is to reliably render fast variations of the core field and its secular variation. This method combines a sequential modelling approach, a Kalman filter, and a correlation-based modelling step. Sources that most significantly contribute to the field measured at the surface of the Earth are modelled. Their separation is based on strong prior information on their spatial and temporal behaviours. We obtain a time series of model distributions which display behaviours similar to those of recent models based on more classic approaches, particularly at large temporal and spatial scales. Interesting new features and periodicities are visible in our models at smaller time and spatial scales. An important aspect of our method is to yield reliable error bars for all model parameters. These errors, however, are only as reliable as the description of the different sources and the prior information used are realistic. Finally, we used a slightly different version of our method to produce candidate models for the thirteenth edition of the International Geomagnetic Reference Field.

International audience; The use of ochre has been documented in many Middle Stone Age sites of Southern Africa. However, the literature on the exploitation of ochre within the archaeological contexts of Later Stone Age (LSA) rock art sites is scarce. Despite the discovery of several painted shelters within the Erongo Mountains (Namibia), no archaeological study of ochre assemblages has been conducted in the region. Here, we present the archaeological ochre assemblage recovered from a LSA sequence at the rock art shelter of Leopard Cave (Erongo, Namibia), spanning ca. 5,700 to 2,100 cal. BP. The use-wear traces present on some ochre fragments and the stone tools bearing red residues are indicative of different stages of ochre processing at the site. The presence of other artifacts, such as ostrich eggshell and bone beads with red residues, and the existence of rock paintings in the cave are pointers to the importance of ochre for understanding the sociocultural behaviors of the LSA populations in central Namibia.; Bien que de nombreux sites du Middle Stone Age d'Afrique australe documentent l'utilisation de matières colorantes ferrugineuses, la littérature existante sur leur utilisation dans des contextes archéologiques de sites d'art rupestre du Later Stone Age (LSA) est rare. Malgré la découverte de plusieurs abris ornés riches de nombreux blocs de matières colorantes ferrugineuses dans les monts Erongo (Namibie), aucune étude n'a été mené sur ces matières premières dans cette région. Nous présentons dans cet article l'assemblage archéologique de matières colorantes ferrugineuses récupérées dans l'abri orné de Leopard Cave (Erongo, Namibie) au sein d'newapos;une séquence LSA, s'étendant d'environ 5700 à 2100 cal. a. BP. Les traces d'utilisations présentes sur certains blocs de matières colorantes ferrugineuses et la présence d'outils en pierre portant des traces de résidus rouges à leur surface attestent de l'existence de différentes « chaînes opératoires » de traitement des matières colorantes ferrugineuses sur le site. La présence d'autres artefacts portant des traces de résidus rouges tels que des perles en coquille d'oeuf d'autruche ou en os et l'existence dans l'abri de peintures rupestres soulignent l'importance d'étudier les matières colorantes pour comprendre les comportements socio-culturels des populations LSA en Namibie centrale.

Dwarf novae (DNe) and low mass X-ray binaries (LMXBs) show eruptions that are thought to be due to a thermal-viscous instability in their accretion disk. These eruptions provide constraints on angular momentum transport mechanisms. We explore the idea that angular momentum transport could be controlled by the dynamical evolution of the large scale magnetic field. We study the impact of different prescriptions for the magnetic field evolution on the dynamics of the disk. This is a first step in confronting the theory of magnetic field transport with observations. We develop a version of the disk instability model that evolves the density, the temperature and the large scale vertical magnetic flux together. We take into account the accretion driven by turbulence or by a magnetized outflow. To evolve the magnetic flux, we use a toy model with physically motivated prescriptions depending mainly on the local magnetization. We find that allowing magnetic flux to be advected inwards provides the best agreement with DNe lightcurves. This leads to a hybrid configuration with an inner magnetized disk, driven by angular momentum losses to an MHD outflow, sharply transiting to an outer weakly-magnetized turbulent disk, where the eruptions are triggered. The dynamical impact is equivalent to truncating a viscous disk so that it does not extend down to the compact object, with the truncation radius dependent on the magnetic flux and evolving as $\dot{M}^{-2/3}$. Models of DNe and LMXBs lightcurves typically require the outer, viscous disk to be truncated in order to match observations. There is no generic explanation for this truncation. We propose that it is a natural outcome of the presence of large-scale magnetic fields in both DNe and LMXBs, the magnetic flux accumulating towards the center to produce a magnetized disk with a fast accretion timescale., Comment: Accepted for publication in A&A. 15 pages, 8 Figures, 1 page of Appendix

Within the Egyptian Western Desert, the Kharga Oasis was a particularly favourable and highly frequented area during the Holocene thanks to a permanent ground water supply. The high concentration and accessibility of archaeological sites here allows the cultural and economic changes to be documented at a local scale, when northeastern Africa was experiencing strong climatic variations and the transition to a food production economy. An expansive program led by the Institut francais d’archeologie orientale (IFAO) which included systematic survey, sampling collections, tests and stratigraphic excavations has dramatically increased the amount of data available concerning the prehistory of the Kharga Oasis. Typo-technological analyses focusing on the lithic industries, and other aspects of material culture, plus a series of 14C dates have led to the definition of four main successive cultural phases: Kharga A, B, C and D. This paper describes this proposal of a new archaeological sequence for human occupation in the Kharga Oasis and discusses its integration in the wider frame of Egypt and the Eastern Sahara.

Context. Disks around pre-main-sequence stars evolve over time by turbulent viscous spreading. The main contender to explain the strength of the turbulence is the Magneto-Rotational-Instability (MRI) model, whose efficiency depends on the disk ionization fraction. Aims. We aim at computing self-consistently the chemistry including PAH charge chemistry, the grain charging and an estimate of an effective value of the turbulence alpha parameter in order to find observational signatures of disk turbulence. Methods. We introduced PAH and grain charging physics and their interplay with other gas-phase reactions in the physico-chemical code ProDiMo. Non-ideal magnetohydrodynamics effects such as Ohmic and ambipolar diffusion are parametrized to derive an effective value for the turbulent parameter alpha_eff . We explored the effects of turbulence heating and line broadening on CO isotopologue sub-millimeter lines. Results. The spatial distribution of alpha_eff depends on various unconstrained disk parameters such as the magnetic parameter beta_mag or the cosmic ray density distribution inside the protoplanetary disks. The inner disk midplane shows the presence of the so-called dead-zone where the turbulence is quasi-inexistent. The disk is heated mostly by thermal accommodation on dust grains in the dead-zone, by viscous heating outside the dead-zone up to a few hundred astronomical units, and by chemical heating in the outer disk. The CO rotational lines probe the warm molecular disk layers where the turbulence is at its maximum. However, the effect of turbulence on the CO line profiles is minimal and difficult to distinguish from the thermal broadening. Conclusions. Viscous heating of the gas in the disk midplane outside the dead-zone is efficient. The determination of alpha from CO rotational line observations alone is challenging., accepted to A&A. 29 pages

Across the European continent, the integration of increasing numbers of renewable energy sources within the electricity grids has become a strategic objective, requiring the modernization and expansion of the grids. In particular, recent studies have emphasized the major role of bulk power lines with lengths of several hundred kilometers. These pan-European transmission corridors with capacities of 5 to 20 GW were shown to be necessary, no matter which energy scenario is explored [1], [2].

Mars is characterized by a strong crustal magnetic field, particularly over its southern hemisphere, which is believed to be the remnant of an ancient core dynamo. The dynamo ceased operating approximately 4 Ga ago, although the exact time is still under debate. The scope of this study is to introduce constraints on the possible timing of its cessation by studying the magnetization signatures over some craters which have reliable crater retention ages and are large enough for the impact to have reset the crustal magnetization within.

(shortened) Planet forming discs are believed to be very weakly turbulent in the regions outside of 1 AU. For this reason, it is now believed that magnetized winds could be the dominant mechanism driving accretion in these systems. However, there is today no self-consistent way to describe discs subject to a magnetized wind, in a way similar to the $\alpha$ disc model. In this article, I explore in a systematic way the parameter space of wind-driven protoplanetary discs and present scaling laws which can be used in reduced models \`a la alpha-disc. Methods: I compute a series of self-similar wind solutions, assuming the disc is dominated by ambipolar and Ohmic diffusions. These solution are obtained by looking for stationary solutions in the finite-volume code PLUTO using a relaxation method and continuation. Results: Self-similar solutions are obtained for values of plasma beta ranging from 10^2 to 10^8, for several Ohmic and ambipolar diffusion strengths. Mass accretions rates of the order of 10^{-8} Msun/yr are obtained for poloidal field strength beta=O(10^4) or equivalently 1 mG at 10 AU. The resulting magnetic lever arms are typically lower than 2, possibly reaching 1.5 in weakest field cases. Finally, I provide a complete set of scaling laws and semi-analytical wind solutions, which can be used to fit and interpret observations. Conclusions: Magnetized winds are unavoidable in protoplanetary discs as soon as they are embedded in an ambient poloidal magnetic field. Very detailed disc microphysics are not always needed to describe them, and simplified models such as self-similar solutions manage to capture most of the physics seen in full 3D simulations. The remaining difficulty to get a complete theory of wind-driven accretion lies in the transport of the large scale field, which remains poorly constrained and not well understood., Comment: 13 pages, 14 figures, accepted for publication in A&A

BEST PATHS (acronym for “BEyond State-of-the-art Technologies for rePowering ac corridors and multi-Terminal HVDC Systems”) is a collaborative project of 40 leading European organizations from science and industry, supported by the 7th Research Framework Programme of the European Commission. The project investigates the feasibility of technological innovations that could advance high-capacity transmission links. These innovations include a demonstrator project dedicated to superconducting electric lines, which aims to validate the novel MgB2 technology for GW-level HVDC power transmission. The four-year project will thus demonstrate the operation of a full-scale 320 kV MgB2 monopole cable system that can transfer up to 3.2 GW. This paper focuses on the design and development activities for the 10 kA cable conductor, which were carried out in the first two years of the project.

An efficient conversion of chitin, the second most abundant renewable polymer on the Earth, into N-acetylglucosamine and N,N′-diacetylchitobiose, using room temperature ionic liquids (RTILs) and commercially available chitinases is described for the first time. The sequential strategy consists of the use of RTILs to pretreat chitin under mild conditions as a first step before enzymatic hydrolysis. [C2mim][OAc] (1-ethyl-3-methyl imidazolium) pretreatment provides an efficient production of N-acetylglucosamine (185.0 ± 4.0 mg per g chitin) or N,N′-diacetylchitobiose (667.60 ± 20.71 mg per g chitin) catalyzed by chitinase from Trichoderma viride or Streptomyces griseus, respectively. A thorough investigation of the structural changes of chitin induced by RTIL pretreatment suggested an increase in enzymes’ accessibility to the chitin substrate. Alternatively, a one-pot enzymatic hydrolysis of chitin in [C2mim][OAc]-aqueous medium constitutes a promising simultaneous route to selectively generate N-acetylglucosamine or N,N′-diacetylchitobiose by decreasing the required [C2mim][OAc] amount and the number of steps. Finally, the combination of the two chitinases from T. viride and S. griseus was shown to be very relevant to considerably increase the production of N-acetylglucosamine up to 760.0 ± 0.1 mg per g chitin.

The Earth’s magnetic field as it is measured by low-Earth orbit satellites such as Swarm and CHAMP results from the superposition of internal and external source fields overlapping in time and in space. The Earth’s lithospheric field is one of the weakest sources detectable from space and its accurate description requires treatments of rapidly-varying magnetic fields generated by current systems in the ionosphere and magnetosphere. In this paper, we review methods most commonly used in geomagnetism to identify and then to correct for the external perturbation fields at satellite altitudes. We document the pros and cons of Fourier Filtering, polynomial and Spherical Harmonics analyses, Singular Spectral Analysis (SSA) and Line-levelling techniques. The difficulties are illustrated with an application of the methods on a common set of real Swarm magnetic field measurements and with a discussion on the differences between lithospheric field models obtained with each treatment. We finally discuss some perspectives for improvements of external field correction techniques relying on statistical or more explicit assumptions about the geographical distribution as well as the shape and strengths of the external magnetic field structures.

International audience; We study the evolution of one million test particles in a turbulent plasma simulation, using the gyrokinetic code Trapped Element REduction in Semi-Lagrangian Approach (TERESA), as a method to get insights into the type of transport governing the plasma. TERESA (Trapped Element REduction in Semi-Lagrangian Approach) is a collisionless global 4D code which treats the trapped particles kinetically, while the passing particles are considered adiabatic. The Vlasov-Poisson system of equations is averaged over the cyclotron and the trapped particle's bounce motion, and thus, the model focuses on slow phenomena of the order of the toroidal precession motion of the banana orbits. We initialize the test particles, which are de facto “test banana-centers,” at a time of the simulation when the plasma is turbulent. We impose an initial temperature and density gradients, and only the Trapped Ion Mode (TIM) instability can develop in this system. We then calculate the Mean Squared Displacement of the test particles as a function of time in order to obtain a random walk diffusion coefficient. We observe that the radial diffusion of the test particles depends on their toroidal precession kinetic energy (E), in such a way that the transport of particles is dominated by a strong, relatively narrow peak at the resonant energies. A radial particle diffusion flux is then calculated and compared to the total radial particle flux accounting for all the transport processes such as diffusion and advection which is obtained directly from the TERESA code. We can thus compare the diffusive contribution to the particle flux against the nondiffusive contributions. The results show that the total flux is essentially diffusive which is consistent with our simulation setup aiming for “global turbulence.” Both fluxes present a peak around a resonance energy ER≈1.74Ti between the TIM and the particles. Both thermal and high-energy particles do not contribute significantly to radial transport