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The Pliocene epoch (~2.6-5.3 million years ago) is one of the best resolved examples of a climate state in long-term equilibrium with current or predicted near-future atmospheric CO2 concentrations, characterised by a globally warmer climate, reduced continental ice volume, and reduced ocean/atmosphere circulation intensity compared to today. Towards the end of the Pliocene, there was a marked increase in glaciation in the northern hemisphere and atmospheric CO2 concentrations declined. The Past Global Changes (PAGES) PlioVAR working group aimed to co-ordinate a synthesis of terrestrial and marine data to characterise spatial and temporal variability of Pliocene climate, underpinned by high quality data sets supported by robust stratigraphies. Here we present some of the main findings of this synthesis effort, including new assessments of ocean temperatures during the KM5c interglacial, and recent work assessing orbital-scale climate variability across the late Pliocene-early Pleistocene northern hemisphere ice-sheet growth. We outline our approaches to integrating multi-proxy data recording ocean temperatures, d18O and sea-level variability from a globally distributed suite of marine sediment cores. We explore regional expressions of environmental change across this transition, identifying asynchronous trends and patterns in climate changes. We consider how these results might inform our understanding of past climate forcings and feedbacks during both warm intervals of the past and the development of larger ice sheets in the northern hemisphere.

The structure of social networks strongly affects how different phenomena spread in human society, from the transmission of information to the propagation of contagious diseases. It is well-known that heterogeneous connectivity strongly favors spread, but a precise characterization of the redundancy present in social networks and its effect on the robustness of transmission is still lacking. This gap is addressed by the metric backbone, a weight- and connectivity-preserving subgraph that is sufficient to compute all shortest paths of weighted graphs. This subgraph is obtained via algebraically-principled axioms and does not require statistical sampling based on null-models. We show that the metric backbones of nine contact networks obtained from proximity sensors in a variety of social contexts are generally very small, 49% of the original graph for one and ranging from about 6% to 20% for the others. This reflects a surprising amount of redundancy and reveals that shortest paths on these networks are very robust to random attacks and failures. We also show that the metric backbone preserves the full distribution of shortest paths of the original contact networks—which must include the shortest inter- and intra-community distances that define any community structure—and is a primary subgraph for epidemic transmission based on pure diffusion processes. This suggests that the organization of social contact networks is based on large amounts of shortest-path redundancy which shapes epidemic spread in human populations. Thus, the metric backbone is an important subgraph with regard to epidemic spread, the robustness of social networks, and any communication dynamics that depend on complex network shortest paths.Author summaryIt is through social networks that contagious diseases spread in human populations, as best illustrated by the current pandemic and efforts to contain it. Measuring such networks from human contact data typically results in noisy and dense graphs that need to be simplified for effective analysis, without removal of their essential features. Thus, the identification of a primary subgraph that maintains the social interaction structure and likely transmission pathways is of relevance for studying epidemic spreading phenomena as well as devising intervention strategies to hinder spread. Here we propose and study the metric backbone as an optimal subgraph for sparsification of social contact networks in the study of simple spreading dynamics. We demonstrate that it is a unique, algebraically-principled network subgraph that preserves all shortest paths. We also discover that nine contact networks obtained from proximity sensors in a variety of social contexts contain large amounts of redundant interactions that can be removed with very little impact on community structure and epidemic spread. This reveals that epidemic spread on social networks is very robust to random interaction removal. However, extraction of the metric backbone subgraph reveals which interventions—strategic removal of specific social interactions—are likely to result in maximum impediment to epidemic spread.

International audience; We here consider inner amenability from a geometric and group theoretical perspective. We prove that for every non-elementary action of a group G on a finite dimensional irreducible CAT(0) cube complex, there is a nonempty G-invariant closed convex subset such that every conjugation invariant mean on G gives full measure to the stabilizer of each point of this subset. Specializing our result to trees leads to a complete characterization of inner amenability for HNN-extensions and amalgamated free products. One novelty of the proof is that it makes use of the existence of certain idempotent conjugation-invariant means on G. We additionally obtain a complete characterization of inner amenabil-ity for permutational wreath product groups. One of the main ingredients used for this is a general lemma which we call the location lemma, which allows us to "locate" conjugation invariant means on a group G relative to a given normal subgroup N of G. We give several further applications of the location lemma beyond the aforementioned characterization of inner amenable wreath products.

International audience; The rapidly-growing business of ride-on-demand (RoD) service such as Uber, Lyft and Didi proves the effectiveness of their new service model-using mobile apps and dynamic pricing to coordinate between drivers, passengers and the service provider, to manipulate the supply and demand, and to improve service responsiveness as well as quality. Despite its success, dynamic pricing creates a new problem for drivers: how to seek for passengers to maximize revenue under dynamic prices. Seeking route recommendation has already been studied extensively in traditional taxi service, but most studies do not consider the effects of taxis and passengers on the seeking taxi simultaneously. Further, in RoD service it is necessary to consider more factors such as dynamic prices, the status of other transportation services, etc. In this paper, we employ a force-directed approach to model, by analogy, the relationship between vacant cars and passengers as that between positive and negative charges in electrostatic field. We extract features from multi-source urban data to describe dynamic prices, the status of RoD, taxi and public transportation services, and incorporate them into our model. The model is then used in route recommendation in every intersection so that a driver in a vacant RoD car knows which road segment to take next. We conduct extensive experiments based on our multi-source urban data, including RoD service operational data, taxi GPS trajectory data and public transportation distribution data, and results not only show that our approach outperforms existing baselines, but also justify the need to incorporate multi-source urban data and dynamic prices.

Significance The glutamine transporter ASCT2 is an emerging therapeutic target for various cancer types. Here, we use an integrated computational and experimental approach to develop unique ASCT2 inhibitors targeting a conformational state useful for rational drug design. We apply computational chemistry tools such as molecular docking and molecular dynamics simulations, in combination with structure determination with cryo-electron microscopy and synthetic chemistry, to design multiple ASCT2 inhibitors. Our results reveal a unique mechanism of stereospecific inhibition of ASCT2 and highlight the utility of combining state-of-the-art computational and experimental approaches in characterizing challenging human membrane protein targets., ASCT2 (SLC1A5) is a sodium-dependent neutral amino acid transporter that controls amino acid homeostasis in peripheral tissues. In cancer, ASCT2 is up-regulated where it modulates intracellular glutamine levels, fueling cell proliferation. Nutrient deprivation via ASCT2 inhibition provides a potential strategy for cancer therapy. Here, we rationally designed stereospecific inhibitors exploiting specific subpockets in the substrate binding site using computational modeling and cryo-electron microscopy (cryo-EM). The final structures combined with molecular dynamics simulations reveal multiple pharmacologically relevant conformations in the ASCT2 binding site as well as a previously unknown mechanism of stereospecific inhibition. Furthermore, this integrated analysis guided the design of a series of unique ASCT2 inhibitors. Our results provide a framework for future development of cancer therapeutics targeting nutrient transport via ASCT2, as well as demonstrate the utility of combining computational modeling and cryo-EM for solute carrier ligand discovery.

International audience; Hard X-ray photoelectron spectroscopy (HAXPES) is a powerful technique to observe chemical and electronic states of atoms buried inside materials. Recently, a laboratory-based HAXPES system with high throughput has been developed, combining a high-flux Ga (Kα＝9.25 keV) X-ray source and a high-transmission photoelectron analyser. In this article, research using the HAXPES Lab is reviewed, and the data are compared with those using synchrotron light sources. The HAXPES Lab is an attractive option not only for scientists but also for industrialists needing rapid answers for research and development.

Publié dans BioRxiv le 31 mai 2020.; ASCT2 (SLC1A5) is a sodium-dependent neutral amino acid transporter that controls amino acid homeostasis in peripheral tissues. ASCT2 is upregulated in cancer, where it modulates intracellular glutamine levels, fueling cell proliferation. Nutrient deprivation via ASCT2 inhibition provides an emerging strategy for cancer therapy. Here, guided by a homology model of ASCT2 in an outward-facing conformation, we rationally designed novel inhibitors exploiting stereospecific pockets in the substrate binding site. A cryo-EM structure of ASCT2 in complex with inhibitor ( Lc -BPE) validated our predictions and was subsequently refined based on computational analysis. The final structures, combined with MD simulations, show that the inhibitor samples multiple conformations in the ASCT2 binding site. Our results demonstrate the utility of combining computational modeling and cryo-EM for SLC ligand discovery, and a viable strategy for structure determination of druggable conformational states for challenging membrane protein targets.

Following cue-outcome (X-O) pairings, 2 procedures that reduce conditioned responses to X are extinction, in which X is presented by itself, and counterconditioning, in which X is paired with a different outcome typically of valence opposite that of training. Although studies with animals have generally found counterconditioning more efficient than extinction in reducing responding, data from humans are less clear. They suggest counterconditioning is more efficient than extinction at interfering with emotional processing, but there is little difference between the two procedures regarding their impact on the verbal assessment of the probability of the outcome given the cue. However, issues of statistical power leave conclusions ambiguous. We compared counterconditioning and extinction in highly powered experiments that exploited a novel procedure. A rapid streamed-trial procedure was used in which participants were asked to rate how likely a target outcome was to accompany a target cue after being exposed to acquisition trials followed by extinction, counterconditioning, or neither. In Experiments 1 and 2, evaluative conditioning was assessed by asking participants to rate the pleasantness of the cues after treatment. These studies found counterconditioning more efficient than extinction at reducing evaluative conditioning but less efficient at decreasing the assessment of the conditional probability of the outcome given the cue. The latter effect was replicated with neutral outcomes in Experiments 3 and 4, but the effect was inverted in Experiment 4 in conditions designed to preclude reinstatement of initial training by the question probing the conditional probability of the outcome given the cue. Effect sizes were small (Cohen's d of 0.2 for effect on evaluative conditioning, Cohen's d of 0.3 for effect on the outcome expectancy). If representative, this poses a serious constraint in terms of statistical power for further investigations of differential efficiency of extinction and counterconditioning in humans. (PsycInfo Database Record (c) 2020 APA, all rights reserved). 46

A signed graph is a graph together with an assignment of signs to the edges. A closed walk in a signed graph is said to be positive (negative) if it has an even (odd) number of negative edges, counting repetition. Recognizing the signs of closed walks as one of the key structural properties of a signed graph, we define a homomorphism of a signed graph $(G,\sigma)$ to a signed graph $(H, \pi)$ to be a mapping of vertices and edges of $G$ to (respectively) vertices and edges of $H$ which preserves incidence, adjacency and the signs of closed walks. In this work we first give a characterization of the sets of closed walks in a graph $G$ that correspond to the set of negative walks in some signed graph on $G$. We also give an easy algorithm for the corresponding decision problem. After verifying the equivalence between this definition and earlier ones, we discuss the relation between homomorphisms of signed graphs and those of 2-edge-colored graphs. Next we provide some basic no-homomorphism lemmas. These lemmas lead to a general method of defining chromatic number which is discussed at length. Finally, we list a few problems that are the driving force behind the study of homomorphisms of signed graphs., Comment: 27 pp., one figure. v2: minor updates

In order to achieve high practical security, Natural Steganography (NS) uses cover images captured at ISO sensitivity $ISO_{1}$ and generates stego images mimicking ISO sensitivity $ISO_{2}>ISO_{1}$. This is achieved by adding a stego signal to the cover that mimics the sensor photonic noise. This paper proposes an embedding mechanism to perform NS in the JPEG domain after linear developments by explicitly computing the correlations between DCT coefficients before quantization. In order to compute the covariance matrix of the photonic noise in the DCT domain, we first develop the matrix representation of demosaicking, luminance averaging, pixel section, and 2D-DCT. A detailed analysis of the resulting covariance matrix is done in order to explain the origins of the correlations between the coefficients of $3\times3$ DCT blocks. An embedding scheme is then presented that takes in order to take into account all the correlations. It employs 4 sub-lattices and 64 lattices per sub-lattices. The modification probabilities of each DCT coefficient are then derived by computing conditional probabilities from the multivariate Gaussian distribution using the Cholesky decomposition of the covariance matrix. This derivation is also used to compute the embedding capacity of each image. Using a specific database called E1 Base, we show that in the JPEG domain NS (J-Cov-NS) enables to achieve high capacity (more than 2 bits per non-zero AC DCT) and with high practical security ($P_{\mathrm{E}}\simeq40\%$ using DCTR from QF 75 to QF 100)., 13 pages, 14 figures

International audience; We introduce and explore a natural rank for totally disconnected locally compact groups called the bounded conjugacy rank. This rank is shown to be a lattice invariant for lattices in sigma compact totally disconnected locally compact groups; that is to say, for a given sigma compact totally disconnected locally compact group, some lattice has bounded conjugacy rank n if and only if every lattice has bounded conjugacy rank n. Several examples are then presented.

This artifact includes source code, scripts and datasets required to reproduce the experimental figures in the evaluation of the MM'18 paper, which is entitled "MiniView Layout for Bandwidth-Efficient 360-Degree Video". The artifact reports the comparison results among the standard cube layout (CUBE), the equi-angular layout (EAC), and the MiniView layout (MVL) in terms of compressed video size, visual quality of views and decoding and rendering time.

International audience; Payload-scaling laws of imperfect steganography inform the steganographer about how the size of secret payload should grow with cover size for constant statistical detectability. In this letter, we carry out an empirical study for the case when the steganographer and the steganalyst operate at a game-theoretic equilibrium. We first explore the possibility to leverage a generalization of the square root law to content-adaptive steganography due to Ker. Since this result does not appear to be tight enough for realistic cover sizes, we instead work with a detectability limited sender in image sources with a forced model as well as real images in both spatial and JPEG domain. The scaling is observed in practice when the images are carefully cropped to preserve the distribution of costs across scales.

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International audience; This paper describes the architecture and training of detectors developed for the ALASKA steganalysis challenge. For each quality factor in the range 60-98, several multi-class tile detectors implemented as SRNets were trained on various combinations of three input channels: luminance and two chrominance channels. To accept images of arbitrary size, the detector for each quality factor was a multi-class multi-layered perceptron trained on features extracted by the tile detectors. For quality 99 and 100, a new "reverse JPEG compatibility attack" was developed and also implemented using the SRNet via the tile detector. Throughout the paper, we explain various improvements we discovered during the course of the competition and discuss the challenges we encountered and trade offs that had to be adopted in order to build a detector capable of detecting steganographic content in a stego source of great diversity.

This short paper is an extension of a family of embedding schemes called Natural Steganography, which embeds a message by mimicking heteroscedastic sensor noise in the JPEG domain. Under the assumption that the development from RAW uses linear de- mosaicking, we derive a closed-form for the covariance matrix of DCT coefficients from 3 × 3 JPEG blocks. This computation relies on a matrix formulation of all steps involved in the development pipeline, which includes demosaicking, conversion to luminance, DCT transform, and reordering. This matrix is then used for pseudo-embedding in the JPEG domain on four lattices of 8 × 8 DCT blocks. The results obtained with the computed covariance matrix are contrasted with the results previously obtained with the covariance matrix estimated using Monte Carlo sampling and scaling. The empirical security using DCTR features at JPEG quality 100 increased from PE = 14% using covariance estimation and scaling to PE = 43% using the newly derived analytic form.

International audience; Second-order conditioning (SOC; i.e., conditioned responding to S2 as a result of S1-US pairings followed by S2-S1 pairings) is generally explained by either a direct S2→US association or by an associative chain (i.e., S2→S1→US). Previous research found that differences in responses to S2 after S1 was extinguished often depended on the nature of the S2-S1 pairings (i.e., sequential or simultaneous). In two experiments with human participants, we examined the possibility that such differences result from S1 evoking S2 during extinction of S1 following simultaneous but not sequential S2-S1 pairings. This evocation of S2 by S1 following simultaneous pairings may have paired the evoked representation of S2 with absence of the outcome, thereby facilitating mediated extinction of S2. Using sequential S2-S1 pairings, both Experiments 1 and 2 failed to support this account of how extinction of S1 reduced responding to S2. Experiment 1 found that extinguishing S1 reduced responding to S2, while extinguishing S2 had little effect on responses to S1, although forward evocation of S1 during extinction of S2 paired the evoked representation of S1 with absence of the outcome. In Experiment 2, evocation of S2 during S1 nonreinforced trials was prevented because S2-S1 pairings followed (rather than proceeded) S1-alone exposures. Nevertheless, responding to S2 at test mimicked S1 responding. Responding to S2 was high in the context in which S1 had been reinforced and low in the context in which S1 had been nonreinforced. Collectively, these experiments provide additional support for the associative-chain account of SOC.

International audience; Duchenne muscular dystrophy (DMD), the most common lethal genetic disorder, is caused by mutations in the dystrophin (DMD) gene. Exon skipping is a therapeutic approach that uses antisense oligonucleotides (AOs) to modulate splicing and restore the reading frame, leading to truncated, yet functional protein expression. In 2016, the US Food and Drug Administration (FDA) conditionally approved the first phosphorodiamidate morpholino oligomer (morpholino)-based AO drug, eteplirsen, developed for DMD exon 51 skipping. Eteplirsen remains controversial with insufficient evidence of its therapeutic effect in patients. We recently developed an in silico tool to design antisense morpholino sequences for exon skipping. Here, we designed morpholino AOs targeting DMD exon 51 using the in silico tool and quantitatively evaluated the effects in immortalized DMD muscle cells in vitro. To our surprise, most of the newly designed morpholinos induced exon 51 skipping more efficiently compared with the eteplirsen sequence. The efficacy of exon 51 skipping and rescue of dystrophin protein expression were increased by up to more than 12-fold and 7-fold, respectively, compared with the eteplirsen sequence. Significant in vivo efficacy of the most effective morpholino, determined in vitro, was confirmed in mice carrying the human DMD gene. These findings underscore the importance of AO sequence optimization for exon skipping.

International audience; The purpose of this study is to prepare a source of realistic looking images in which optimal steganalysis is possible by enforcing a known statistical model on image pixels to assess the efficiency of detectors implemented using machine learning. Our goal is to answer the questions that researchers keep asking: "Are our empirical detectors close to what can be possibly detected? How much room is there for improvement?" or simply "Are we there yet?" Our goal is achieved by applying denoising to natural images to remove complex statistical dependencies introduced by processing and, subsequently, adding noise of simpler and known statistical properties that allows deriving the likelihood ratio test in a closed form. This theoretical upper bound informs us about the amount of further possible improvement. Three content-adaptive stego algorithms in the spatial domain and non-adaptive LSB matching are used to contrast the upper bound with the performance of two modern detection paradigms: a convolutional neural network and a classifier with the maxSRMd2 rich model. The short answer to the posed question is "We are much closer now but there is still non-negligible room for improvement."

International audience; Using Natural Steganography (NS), a cover raw image acquired at sensitivity ISO 1 is transformed into a stego image whose statistical distribution is similar to a cover image acquired at sensitivity ISO 2 > ISO 1. This paper proposes such an embedding scheme for color sensors in the JPEG domain, extending thus the prior art proposed for the pixel domain and the JPEG domain for monochrome sensors. We first show that color sensors generate strong intra-block and inter-block dependencies between DCT coefficients and that theses dependencies are due to the demosaicking step in the development process. Capturing theses dependencies using an empirical covariance matrix, we propose a pseudo-embedding algorithm on greyscale JPEG images which uses up to four sub-lattices and 64 lattices to embed information while preserving the estimated correlations among DCT coefficients. We then compute an approximation of the average embedding rate w.r.t. the JPEG quality factor and evaluate the empirical security of the proposed scheme for linear and non-linear demosaicing schemes. Our experiments show that we can achieve high capacity (around 2 bit per nzAC) with a high empirical security (P E 30% using DCTR at QF 95).

International audience; Two cores from the southern Kenya Rift (Koora and Magadi basins) were recovered through the Hominin Sites and Paleolakes Drilling Project and the Olorgesailie Drilling Project. Each contains a detailed environmental history of up to ~1 Ma that correlates with much of the 1.2 Ma outcrop sedimentary record of the neighboring Olorgesailie Basin. The Magadi core, MAG14-2A, reached trachyte at 194 m and includes zeolitic, laminated and massive clay and silt, calcareous mud, limestone, chert and trona. The Koora core (OLO12-1A) extended to depths of 166 m and contains laminated and massive diatomites, fine to coarse sands, lime and siliciclastic mud, with pumice-rich gravels. The two cores are particularly important because they fill erosional gaps in the environmental history of the Olorgesailie Basin, which includes important evidence for changing hominin cultures and evolution.Diatoms are present in much of the Koora and Magadi basin sediments. These are dominated by a variety of planktonic Aulacoseira, Cyclotella and Thalassiosira taxa in both basins. These and other taxa provide a detailed record of lakes that fluctuated in depth, extent and chemistry, and reveal the presence of wetlands, freshwater and saline lakes. Diatom transfer functions indicate that the water bodies fluctuated widely in conductivity between ~200 to >20,000 μS cm−1, with pH changing between about 7.5 and 11.5. The palaeolakes also periodically exceeded diatom tolerance limits and intermittently dried out. Pollen are generally lacking in the Koora basin sediments, but deposits in the Magadi core contain common pollen that document a wide range of habitats, including forests, woodlands and grasslands that could have supported the presence of hominins and their activities in the region. Fungal spore data support pollen inferences and indicate periods when large mammals might have been common.The microfossil record shows a broad trend towards more arid conditions in the southern Kenya Rift after about 550 Ka, interrupted by periodic wetter conditions. A major episode of desiccation developed between ~450 and 325 Ka that partially overlaps with a period of regional mammal extinctions and a change from Acheulean to Middle Stone Age toolkits in the Olorgesailie Basin, which suggests these changes might have been related to environmental conditions.

Our original claim, based on three independent numerical dating methods, of an age of ~185,000 years for the Misliya-1 modern human hemi-maxilla from Mount Carmel, Israel, is little affected by discounting uranium-series dating of adhering crusts. It confirms a much earlier out-of-Africa Homo sapiens expansion than previously suggested by the considerably younger (90,000 to 120,000 years) Skhul/Qafzeh hominins.

We show that an amenable Invariant Random Subgroup of a locally compact second countable group lives in the amenable radical. This answers a question raised in the introduction of the paper "Kesten's Theorem for Invariant Random Subgroup" by Abert, Glasner and Virag. We also consider, in the opposite direction, property (T), and prove a similar statement for this property. The Appendix by Phillip Wesolek proves that the set of amenable subgroups is a Borel subset in the Chabauty topology., Comment: We added an Appendix by Phillip Wesolek

International audience; Most current steganographic schemes embed the secret payload by minimizing a heuristically defined distortion. Similarly, their security is evaluated empirically using classifiers equipped with rich image models. In this paper, we pursue an alternative approach based on a locally-estimated multivariate Gaussian cover image model that is sufficiently simple to derive a closed-form expression for the power of the most powerful detector of content-adaptive LSB matching but, at the same time, complex enough to capture the non-stationary character of natural images. We show that when the cover model estimator is properly chosen, state-of-the-art performance can be obtained. The closed-form expression for detectability within the chosen model is used to obtain new fundamental insight regarding the performance limits of empirical steganalysis detectors built as classifiers. In particular, we consider a novel detectability-limited sender and estimate the secure payload of individual images.

International audience; People can form opinions of other individuals based on information about their good or bad behavior. The present study investigated whether this affective learning might depend on memory links formed between initially neutral people and valenced information. First, participants viewed neutral faces paired with sentences describing prosocial or antisocial behaviors. Second, memory suppression manipulations with the potential to aid in the forgetting of valenced information were administered. Using the Think/No think paradigm, the effectiveness of four different suppression instructions was compared: Unguided Suppression, Guided Suppression, Distraction, and Thought Substitution. Overall, all the tasks appreciably reduced affective learning based on prosocial information, but only the Guided Suppression and Thought Substitution tasks reduced affective learning based on antisocial information. These results suggest that weakening the putative memory link between initially neutral people and valenced information can decrease the effect of learned associations on the evaluation of other people. We interpreted this as indicative that social affective learning may rely on declarative memories.

The emergence of symbiotic interactions has been studied using population genomics in nature and experimental evolution in the laboratory, but the parallels between these processes remain unknown. Here we compare the emergence of rhizobia after the horizontal transfer of a symbiotic plasmid in natural populations of Cupriavidus taiwanensis, over 10 MY ago, with the experimental evolution of symbiotic Ralstonia solanacearum for a few hundred generations. In spite of major differences in terms of time span, environment, genetic background, and phenotypic achievement, both processes resulted in rapid genetic diversification dominated by purifying selection. We observe no adaptation in the plasmid carrying the genes responsible for the ecological transition. Instead, adaptation was associated with positive selection in a set of genes that led to the co-option of the same quorum-sensing system in both processes. Our results provide evidence for similarities in experimental and natural evolutionary transitions and highlight the potential of comparisons between both processes to understand symbiogenesis., It is unclear if experimental evolution is a good model for natural processes. Here, Clerissi et al. find parallels between the evolution of symbiosis in rhizobia after horizontal transfer of a plasmid over 10 million years ago and experimentally evolved symbionts.

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International audience; The La Ferrassie 1 (LF1) skeleton, discovered over a century ago, is one of the most important Neandertal individuals both for its completeness and due to the role it has played historically in the interpretation of Neandertal anatomy and lifeways. Here we present new skeletal remains from this individual, which include a complete right middle ear ossicular chain (malleus, incus, and stapes), three vertebral fragments, and two costal remains. Additionally, the study of the skeleton has allowed us to identify new pathological lesions, including a congenital variant in the atlas, a greenstick fracture of the left clavicle, and a lesion in a mid-thoracic rib of unknown etiology. In addition, we have quantified the amount of vertebral pathology, which is greater than previously appreciated. We have complemented the paleopathological analysis with a taphonomic analysis to identify any potential perimortem fractures. The taphonomic analysis indicates that no surface alteration is present in the LF1 skeleton and that the breakage pattern is that of bone that has lost collagen, which would be consistent with the intentional burial of this individual proposed by previous researchers. In this study, we used CT and microCT scans in order to discover new skeletal elements to better characterize the pathological lesions and to quantify the fracture orientation of those bones in which the current plaster reconstruction did not allow its direct visualization, which underlines the broad potential of imaging technologies in paleoanthropological research. A century after its discovery, LF1 is still providing new insights into Neandertal anatomy and behavior.

International audience; The aim of this exploratory study was to examine whether the kurtosis metric can contribute to investigations of the effects of combined exposure to noise and solvents on human hearing thresholds. Twenty factory workers exposed to noise and solvents along with 20 workers of similar age exposed only to noise in eastern China were investigated using pure-tone audiometry (1000–8000 Hz). Exposure histories and shift-long noise recording files were obtained for each participant. The data were used in the calculation of the cumulative noise exposure (CNE) and CNE adjusted by the kurtosis metric for each participant. Passive samplers were used to measure solvent concentrations for each worker exposed to solvents over the full work shift. Results showed an interaction between noise exposure and solvents for the hearing threshold at 6000 Hz. This effect was observed only when the CNE level was adjusted by the kurtosis metric.; Le but de cette étude pilote était d’estimer la pertinence du kurtosis pour évaluer les effets d’une exposition combinée " bruit + solvants " sur les seuils auditifs de salariés. Vingt salariés exposés au bruit et à des solvants, et 20 salariés du même âge, exposés uniquement au bruit, ont été testés dans des entreprises présentes dans l’est de la Chine avec une audiométrie tonale (1000 - 8000 Hz). L’histoire acoustique et les postes occupés au cours de la carrière des salariés ont été obtenus pour chaque volontaire participant. Ces données ont été utilisées pour calculer l’exposition cumulée de bruit (CNE) et la CNE ajustée par le kurtosis. Des exposimètres passifs ont equipé les salariés pour mesurer les concentrations de solvants reçues sur leur poste entier. Les résultats ont montré qu’une interaction entre bruit et solvants existe pour le seuil auditif à la fréquence de 6 kHz. Les effets ont été observés uniquement lorsque que la CNE était ajustée par le kurtosis.

Objectives This study aims to explore the affinities of the Sima de los Huesos (SH) population in relation to Homo neanderthalensis, Arago, and early and contemporary Homo sapiens. By characterizing SH intra‐population variation, we test current models to explain the Neanderthal origins. Materials and Methods Three‐dimensional reconstructions of dentine surfaces of lower first and second molars were produced by micro‐computed tomography. Landmarks and sliding semilandmarks were subjected to generalized Procrustes analysis and principal components analysis. Results SH is often similar in shape to Neanderthals, and both groups are generally discernible from Homo sapiens. For example, the crown height of SH and Neanderthals is lower than for modern humans. Differences in the presence of a mid‐trigonid crest are also observed, with contemporary Homo sapiens usually lacking this feature. Although SH and Neanderthals show strong affinities, they can be discriminated based on certain traits. SH individuals are characterized by a lower intra‐population variability, and show a derived dental reduction in lower second molars compared to Neanderthals. SH also differs in morphological features from specimens that are often classified as Homo heidelbergensis, such as a lower crown height and less pronounced mid‐trigonid crest in the Arago fossils. Discussion Our results are compatible with the idea that multiple evolutionary lineages or populations coexisted in Europe during the Middle Pleistocene, with the SH paradigm phylogenetically closer to Homo neanderthalensis. Further research could support the possibility of SH as a separate taxon. Alternatively, SH could be a subspecies of Neanderthals, with the variability of this clade being remarkably higher than previously thought.

International audience; In natural steganography, the secret message is hidden by adding to the cover image a noise signal that mimics the het-eroscedastic noise introduced naturally during acquisition. The method requires the cover image to be available in its RAW form (the sensor capture). To bring this idea closer to a practical embedding method, in this paper we embed the message in quantized DCT coefficients of a JPEG file by adding independent realiza-tions of the heteroscedastic noise to pixels to make the embedding resemble the same cover image acquired at a larger sensor ISO setting (the so-called cover source switch). To demonstrate the feasibility and practicality of the proposed method and to validate our simplifying assumptions, we work with two digital cameras , one using a monochrome sensor and a second one equipped with a color sensor. We then explore several versions of the embedding algorithm depending on the model of the added noise in the DCT domain and the possible use of demosaicking to convert the raw image values. These experiments indicate that the demo-saicking step has a significant impact on statistical detectability for high JPEG quality factors when making independent embedding changes to DCT coefficients. Additionally, for monochrome sensors or low JPEG quality factors very large payload can be embedded with high empirical security.

Given a transitive permutation group, a fundamental object for studying its higher transitivity properties is the permutation action of its isotropy subgroup. We reverse this relationship and introduce a universal construction of infinite permutation groups that takes as input a given system of imprimitivity for its isotropy subgroup., This produces vast families of kaleidoscopic groups. We investigate their algebraic properties, such as simplicity and oligomorphy; their homological properties, such as acyclicity or contrariwise large Schur multipliers; their topological properties, such as unique Polishability., Our construction is carried out within the framework of homeomorphism groups of topological dendrites.

Earliest modern humans out of AfricaRecent paleoanthropological studies have suggested that modern humans migrated from Africa as early as the beginning of the Late Pleistocene, 120,000 years ago. Hershkovitzet al.now suggest that early modern humans were already present outside of Africa more than 55,000 years earlier (see the Perspective by Stringer and Galway-Witham). During excavations of sediments at Mount Carmel, Israel, they found a fossil of a mouth part, a left hemimaxilla, with almost complete dentition.The sediments contain a series of well-defined hearths and a rich stone-based industry, as well as abundant animal remains. Analysis of the human remains, and dating of the site and the fossil itself, indicate a likely age of at least 177,000 years for the fossil—making it the oldest member of theHomo sapiensclade found outside Africa.Science, this issue p.456; see also p.389

For each $n$, let $A_n=(\sigma_{ij})$ be an $n\times n$ deterministic matrix and let $X_n=(X_{ij})$ be an $n\times n$ random matrix with i.i.d. centered entries of unit variance. We study the asymptotic behavior of the empirical spectral distribution $\mu_n^Y$ of the rescaled entry-wise product \[ Y_n = \left(\frac1{\sqrt{n}} \sigma_{ij}X_{ij}\right). \] For our main result we provide a deterministic sequence of probability measures $\mu_n$, each described by a family of Master Equations, such that the difference $\mu^Y_n - \mu_n$ converges weakly in probability to the zero measure. A key feature of our results is to allow some of the entries $\sigma_{ij}$ to vanish, provided that the standard deviation profiles $A_n$ satisfy a certain quantitative irreducibility property. An important step is to obtain quantitative bounds on the solutions to an associate system of Schwinger--Dyson equations, which we accomplish in the general sparse setting using a novel graphical bootstrap argument., Comment: 50 pages. The original arXiv submission has been split into two parts. This is the first part and was published in the Electronic Journal of Probability. The second part is titled: Non-Hermitian random matrices with a variance profile (II): properties and examples

International audience; Eyewitness testimony can play a crucial role in criminal cases. However, witness memory is fallible. Thus, techniques for assessing witness accuracy are needed. We examined theusefulness of witness recall of contextual information that might be known to the authorities in assessing the likely accuracy of witnesses in describing information unknown and of interestto the authorities. Participants viewed a video of a purse being stolen and were then asked questions about the perpetrator and context of the crime including who (bystanders), when (time of the crime), and where (location of the crime). Participants interrogated soon after witnessing the crime (n=54) exhibited better recall than those not questioned immediately but instead were interrogated for the first time after a 2-day retention interval (n=60). However, interrogation (without feedback) soon after viewing the video reduced forgetting over the 2-day retention interval. Thus, early interrogation can retard subsequent forgetting as suggested by the Testing Effect. Moreover, the quality of recall of the context was positively correlated with recall concerning the perpetrator, and questions concerning bystanders had the highest correlation with perpetrator recall.

As part of the test campaign led by the 27th ITTC Ocean Engineering Committee to produce reliable experimental benchmark data for multiple-body interactions in waves, model tests of two identical models in close proximity were carried out at the towing tank of Memorial University, Canada and at the wave basin of Ecole Centrale de Nantes, France. This paper presents the experimental results for the two bodies in regular waves with various gaps. The experimental data, including motions of two bodies, wave elevations in the gap and drift forces, were compared with numerical solutions based on the potential-flow solution.

International audience; There is a body of research suggesting compromised ability to distinguish between different external sources of information (i.e., external monitoring) in Korsakoff's syndrome. Here we replicate and extend this literature by assessing the ability of patients with Korsakoff's syndrome to distinguish between different external sources of information (i.e., external monitoring), between internal and external sources of information (i.e., reality monitoring), and between different internal sources of information (i.e., internal monitoring). On the external monitoring assessment, patients with Korsakoff's syndrome and controls watched the experimenter place objects (e.g., a toothbrush) in either a black or white box; afterward, they were asked to remember where the objects had been placed. On the reality monitoring assessment, participants had to either place objects or watch the experimenter place objects in a black box; afterward, they were asked to remember whether the objects had been placed in the box by themselves or by the experimenter. On the internal monitoring assessment, participants had to either place objects or imagine themselves placing objects in a black box; afterward, they were asked to remember whether they had previously placed the objects in the box or imagined doing so. Analyses demonstrated lower external and internal monitoring in patients with Korsakoff's syndrome than in controls, but no significant difference was observed between the two populations on the reality monitoring condition. Our data provide preliminary evidence that the ability to recognize oneself as the author of one's own actions may be relatively preserved in Korsakoff's syndrome.

International audience; Second-order conditioning sometimes depends on mediation by first-order cues. The competing assumption, that there is a direct second-order and outcome association, is challenged by experiments that have shown that responding to the second-order cue is attenuated after the first-order cue is extinguished. Alternatively, we propose that extinction of the first order cue could result in mediated extinction to the second-order cue. We will discuss experiments designed to differentiate between these two accounts.

International audience; This paper investigates practical strategies for distributing payload across images with content-adaptive steganography and for pooling outputs of a single-image detector for steganalysis.Adopting a statistical model for the detector’s output, the steganographer minimizes the power of the most powerful detector of an omniscient Warden, while the Warden, informed by the payload spreading strategy, detects with the likelihood ratio test in the form of a matched filter. Experimental results with state-of-the-art content-adaptive additive embedding schemes and rich models are included to show the relevance of the results.

We construct examples of robustly transitive and stably ergodic partially hyperbolic diffeomorphisms $f$ on compact $3$-manifolds with fundamental groups of exponential growth such that $f^n$ is not homotopic to identity for all $n>0$. These provide counterexamples to a classification conjecture of Pujals., 30 pages, 7 figures. Updated version after referee's remarks. To appear in Inventiones Math

no abstract

A gain graph is a graph whose edges are orientably labelled from a group. A weighted gain graph is a gain graph with vertex weights from an abelian semigroup, where the gain group is lattice ordered and acts on the weight semigroup. For weighted gain graphs we establish basic properties and we present general dichromatic and forest-expansion polynomials that are Tutte invariants (they satisfy Tutte's deletion-contraction and multiplicative identities). Our dichromatic polynomial includes the classical graph one by Tutte, Zaslavsky's two for gain graphs, Noble and Welsh's for graphs with positive integer weights, and that of rooted integral gain graphs by Forge and Zaslavsky. It is not a universal Tutte invariant of weighted gain graphs; that remains to be found. An evaluation of one example of our polynomial counts proper list colorations of the gain graph from a color set with a gain-group action. When the gain group is Z^d, the lists are order ideals in the integer lattice Z^d, and there are specified upper bounds on the colors, then there is a formula for the number of bounded proper colorations that is a piecewise polynomial function of the upper bounds, of degree nd where n is the order of the graph. This example leads to graph-theoretical formulas for the number of integer lattice points in an orthotope but outside a finite number of affinographic hyperplanes, and for the number of n x d integral matrices that lie between two specified matrices but not in any of certain subspaces defined by simple row equations., 32 pp. Submitted in 2007, extensive revisions in 2013 (!). V3: Added references, clarified examples. 35 pp

International audience; Steganographic schemes for digital images are routinely designed and benchmarked based on feedback obtained on the standard image set called BOSSbase 1.01. While standardized image sets are important for advancing the field, relying on results from a single source may not provide fair benchmarking and may even lead to designs that are overoptimized and highly suboptimal on other image sources. In this paper, we investigate four modern steganographic schemes for the spatial domain, WOW, S-UNIWARD, HILL, and MiPOD on two more versions of BOSSbase. We observed that with their default settings, the mutual ranking and detectability of all four embedding algorithms can dramatically change across the three image sources. For example, in a version of BOSSbase whose images were cropped instead of resized, all four schemes exhibit almost the same empirical security when steganalyzed with the spatial rich model (SRM). On the other hand, in decompressed JPEG images, WOW is the most secure embedding algorithm out of the four, and this stays true irrespectively of the JPEG quality factor when steganalyzing with both SRM and maxSRM. The empirical security of all four schemes can be increased by optimizing the parameters for each source. This is especially true for decompressed JPEGs. However, the ranking of stego schemes still varies depending on the source. Through this work, we strive to make the community aware of the fact that empirical security of steganographic algorithms is not absolute but needs to be considered within a given environment, which includes the cover source.

galac; International audience

Lazaridis, Iosif et al., We report genome-wide ancient DNA from 44 ancient Near Easterners ranging in time between ~12,000 and 1,400 bc, from Natufian hunter–gatherers to Bronze Age farmers. We show that the earliest populations of the Near East derived around half their ancestry from a ‘Basal Eurasian’ lineage that had little if any Neanderthal admixture and that separated from other non-African lineages before their separation from each other. The first farmers of the southern Levant (Israel and Jordan) and Zagros Mountains (Iran) were strongly genetically differentiated, and each descended from local hunter–gatherers. By the time of the Bronze Age, these two populations and Anatolian-related farmers had mixed with each other and with the hunter–gatherers of Europe to greatly reduce genetic differentiation. The impact of the Near Eastern farmers extended beyond the Near East: farmers related to those of Anatolia spread westward into Europe; farmers related to those of the Levant spread southward into East Africa; farmers related to those of Iran spread northward into the Eurasian steppe; and people related to both the early farmers of Iran and to the pastoralists of the Eurasian steppe spread eastward into South Asia., D.F. and M.N. were supported by Irish Research Council grants GOIPG/2013/36 and GOIPD/2013/1, respectively. S.C. was funded by the Irish Research Council for Humanities and Social Sciences (IRCHSS) ERC Support Programme. Q.F. was funded by the Bureau of International Cooperation of the Chinese Academy of Sciences, the National Natural Science Foundation of China (L1524016) and the Chinese Academy of Sciences Discipline Development Strategy Project (2015-DX-C-03). The Scottish diversity data was funded by the Chief Scientist Office of the Scottish Government Health Directorates (CZD/16/6), the Scottish Funding Council (HR03006), and a project grant from the Scottish Executive Health Department, Chief Scientist Office (CZB/4/285). M.S., A.Tön., M.B. and P.K. were supported by the German Research Foundation (CRC 1052; B01, B03, C01). M.S.-P. was funded by a Wenner-Gren Foundation Dissertation Fieldwork grant (9005), and by the National Science Foundation DDRIG (BCS-1455744). P.K. was funded by the Federal Ministry of Education and Research, Germany (FKZ: 01EO1501). J.F.W. acknowledge the MRC ‘QTL in Health and Disease’ programme grant. The Romanian diversity data was supported by the EC Commission, Directorate General XII (Supplementary Agreement ERBCIPDCT 940038 to the Contract ERBCHRXCT 920032, coordinated by A. Piazza, Turin, Italy). M.R. received support from the Leverhulme Trust’s Doctoral Scholarship programme. O.S. and A.Tor. were supported by the University of Pavia (MIGRAT-IN-G) and the Italian Ministry of Education, University and Research: Progetti Ricerca Interesse Nazionale 2012. The Raqefet Cave Natufian project was supported by funds from the National Geographic Society (grant 8915-11), the Wenner-Gren Foundation (grant 7481) and the Irene Levi-Sala CARE Foundation, while radiocarbon dating on the samples was funded by the Israel Science Foundation (grant 475/10; E. Boaretto). R.P. was supported by ERC starting grant ADNABIOARC (263441). D.R. was supported by NIH grant GM100233, by NSF HOMINID BCS-1032255, and is a Howard Hughes Medical Institute investigator.

International audience; The machine learning paradigm currently predominantly used for steganalysis of digital images works on the principle of fusing the decisions of many weak base learners.In this paper, we employ a statistical model of such an ensemble and replace the majority voting rule with a likelihood ratio test. This allows us to train the ensemble to guarantee desired statistical properties, such as the false-alarm probability and the detection power while preserving the high detection accuracy of original ensemble classifier. It also turns out the proposed test is linear. Moreover, by replacing the conventional total probability of error with an alternative criterion of optimality, the ensemble can be extended to detect messages of an unknown length to address composite hypotheses. Finally, the proposed well-founded statistical formulation allows us to extend the ensemble to multiclass classification with an appropriate criterion of optimality and an optimal associated decision rule. This is useful when a digital image is tested for presence of secret data hidden by more than one steganographic method. Numerical results on real images show the sharpness of the theoretically established results and the relevance of the proposed methodology.