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Purpose: To understand the impact of geochemical sedimentation history for arsenic (As) distribution in the sediment profiles of the Hetao Basin, we (1) evaluated sediments provenance and variations of weathering intensities, (2) attempted to reconstruct the depositional environments, and (3) explored the As and Fe speciation in the sediments. Combining the information above, different sedimentation facies were distinguished in the vertical profiles., Methods: Two sediments cores were drilled up to 80 m depth. Major and trace element compositions, including rare earth elements (REE), were analyzed. Carbon isotope ratios (δ13Corg) of embedded organic matter in the sediments were analyzed by isotope ratio mass spectrometry (IR-MS). Arsenic and Fe speciation of the sediments were determined by sequential extractions., Results and discussion: The similar REE geochemistry of rocks from the Lang Mountains and sediments in the Hetao Basin indicated that the sediments originated from the Lang Mountains. The C/N ratio (~ 4 to ~ 10) in combination with δ13Corg (− 27‰ to −2 4‰) suggested that sediments were mainly deposited in aquatic environments. The unconfined aquifer equaled the lacustrine deposit with less intensive weathering during last glacial maximum (LGM). Here, the As content (average, 5.4 mg kg−1) was higher than in the aquifer sediments below (average, 3.6 mg kg−1)., Conclusion: Higher content of releasable As in combination with paleolake-derived organic matter aquifer sediments probably contributes to higher groundwater As concentration in the unconfined aquifer. This study provides the first insight into the impact of sedimentation history on As distributions in sediment profiles in the Hetao Basin., China Scholarship Council http://dx.doi.org/10.13039/501100004543

International audience; Antibiotic residues in wastewater cause a serious threat to aquatic environment and human safety. Therefore, the development of robust strategies for detecting antibiotic residues becomes critical. In this work, a surface-enhanced Raman scattering (SERS) substrate, consisting of gold nanoparticles/nano diamond/carbon nitride (Au/ND/C3N4) hybrid, which features enhanced light utilization and self-cleaning properties, is developed for sensitive sensing of tetracycline. The fabricated Au/ND/C3N4 substrate effectively captures target molecules and enhances Raman activity, owing to abundant functional groups and light scattering effect of ND. Moreover, the heterostructure formed by Au NPs, ND and C3N4 endows this SERS substrate with superior self-cleaning capability, enabling its reusability. The Au/ND/C3N4 substrate exhibits high sensitivity (10-14 M), desirable reproducibility (RSD = 13.29 %, n = 238) and favourable stability (84.8 % of initial intensity after 30 days) for crystal violet probe. Also, no significant loss of SERS or catalytic activity is observed during cyclic SERS detection. Likewise, the detection of tetracycline at nanomolar level is achieved with good recyclability. This work proposes a distinctive strategy for enhancing SERS activity, and the developed self-cleaning Au/ND/C3N4 substrate represents a potential candidate for highly sensitive detection of antibiotic residues in wastewater.

International audience; Development of reliable sensing strategy combining surface-enhanced Raman scattering (SERS) and surface-assisted laser desorption/ionization-mass spectrometry (SALDI-MS) is of significant interest to distinguish cysteine enantiomers in body fluid for understanding their physiological roles and toxicity hazards. In this work, a SERS/SALDI-MS dual-mode sensing platform of gold nanoparticles (Au NPs) decorated holey carbon nitride (hg-C3N4) was fabricated for sensitive detecting cysteine. The designed Au@hg-C3N4 matrix featured a uniform distribution of Au NPs with the help of anchoring effect of hg-C3N4 holey structure, which was conducive to produce highly repeatable signals. Moreover, the combination of Au NPs and holey g-C3N4 endowed this matrix with superior enrichment capacity, enhanced charge transfer and strong UV absorption. These merits allowed the matrix to acquire high sensitivity and enhanced reproducibility for l-cysteine by means of SERS/SALDI-MS. Likewise, reliable detection of l-cysteine and efficient recognition of d-cysteine in human serum jointly revealed its prospect for detecting cysteine enantiomers in body fluids. This work offers a reliable SERS/SALDI-MS strategy for determining L/D-cysteine enantiomers, and the designed Au@hg-C3N4 matrix becomes a potential application candidate for selective detection of bio-enantiomers.

International audience; The MODIS LAI/FPAR products have been widely used in various fields since their first public release in 2000. This review intends to summarize the history, development trends, scientific collaborations, disciplines involved, and research hotspots of these products. Its aim is to intrigue researchers and stimulate new research direction. Based on literature data from the Web of Science (WOS) and associated funding information, we conducted a bibliometric visualization review of the MODIS LAI/FPAR products from 1995 to 2020 using bibliometric and social network analysis (SNA) methods. We drew the following conclusions: (1) research based on the MODIS LAI/FPAR shows an upward trend with a multiyear average growth rate of 24.9% in the number of publications. (2) Researchers from China and the USA are the backbone of this research area, among which the Chinese Academy of Sciences (CAS) is the core research institution. (3) Research based on the MODIS LAI/FPAR covers a wide range of disciplines but mainly focus on environmental science and ecology. (4) Ecology, crop production estimation, algorithm improvement, and validation are the hotspots of these studies. (5) Broadening the research field, improving the algorithms, and overcoming existing difficulties in heterogeneous surface, scale effects, and complex terrains will be the trend of future research. Our work provides a clear view of the development of the MODIS LAI/FPAR products and valuable information for scholars to broaden their research fields.

International audience; AbstractGold nanoparticles (AuNPs) represent an attractive inorganic matrix for laser desorption/ionization mass spectrometry (LDI-MS) detection of low-molecular-weight analytes; however, their direct use is hindered by severe aggregation. To limit AuNPs aggregation, hexagonal boron nitride nanosheets (h-BNNs) were employed as supports to improve their desorption/ionization efficiency. Thus, Au@BN was synthesized and systematically characterized. It showed low background noise and high sensitivity for LDI-MS of fipronil and its metabolites. Au@BN-assisted LDI-MS was validated using complex samples including blueberry juice, green tea beverage, and fish muscle, achieving low detection limits (0.05–0.20 µg·L−1 for liquid media, 0.82–1.25 ng·g−1 for fish muscle), wide linear ranges (0.2–100 µg·L−1 for liquid media, 3.00–1000 ng·g−1 for fish muscle), high reproducibility (7.55%–13.7%), and satisfactory recoveries (82.62%–109.1%). Furthermore, spatial distributions of analytes in strawberries and zebrafish were successfully imaged. This strategy allows for the quantitative analysis of other small molecules in complex substrates.

Thermo-chemical modeling and chemical data suggest that the genesis of arc melts commonly involves re-melting of older intrusions, triggered by the injection of mantle-derived melts, followed by magma mixing. Remelting and mixing may lead to complex zircon populations, which can be used to gain insights into the conditions of mixing. This paper investigates a case where such processes can be studied through the compositional and thermal record provided by zircons preserved in a diorite dyke swarm that remelted host rock tonalites in the Gangdese Batholith in Tibet. Autocrystic zircons from the diorite yield consistent ages of 46 to 47 Ma even though they can be altered, having highly enriched trace elements, reaching ~1 wt % in Fe, Ca, Y, U, Th, and anomalously high values of LREE and Ti. Granitic magmas derived from the tonalite, back-veined the dykes and mixed with the dioritic mush, transferring small quantities of 77–79 Ma zircon xenocrysts. The xenocrysts are euhedral with little evidence for resorption, indicating that they were apparently stable during the process of tonalite anatexis and transfer to the diorite magma. This requires that: (i) tonalite melting occurred at low temperatures with minimal zircon dissolution, and (ii) the diorite either cooled rapidly before significant resorption of the grains or was already saturated in zircon when mixing occurred. Zircon saturation temperatures of the diorite are relatively low, indicating that xenocrystic zircons were transferred to a highly crystalline dioritic mush. This requires either liquefaction by injection of the back-veining felsic magma to allow for mixing, or pervasive throughflow of the diorite mush by the felsic magma leaving behind zircon xenocrysts. The findings suggest that the dykes triggered low-T, water-fluxed melting of the host tonalite and that these anatectic melts invaded the diorite mush initially through the interstices leading to mixing. This may have caused the breakdown of the crystalline framework leading to liquefaction and renewed magma flow. Dyking and assimilation of wall-rock through back-veining as recorded in these rocks could be common in transcrustal arcs. However, this process could be hidden due to a combination of the similarity in the isotopic and chemical nature of arc rocks and resorption of zircon xenocrysts during mixing. This process may explain some complex chemistry of arc magmatic rocks and their minerals that are not easily explained by endmember models, such as pure re-melting of older arc rocks or fractional crystallization of mantle-derived melts.

International audience; A three-in-one ITO-Cu-ITO multilayer wire strategy is developed to reliably fabricate large-size backplane circuit for micro-LED display. The multilayered wire was prepared by magnetron sputtering and electroplating, and presented a sandwich structure of ITOtransitional layer /Cuseed layer /Cuelectroplating layer/ITOpassivation layer. Synergistic effect among the sandwiched layers endowed the coated wire with good electrical performance (2.31 × 10-3 Ω/sq), favorable adhesion (5B degree) and superior thickness uniformity (8 %), and could ensure reliable machining of glass-based backplane circuit. The fabricated multilayer wire facilitated the development of micro-LED backplane circuit, and was applicable to synthesize large-size (1.1 * 1.3 m2) glass backplane circuit. Field test of micro-LED circuit assembly proved the feasibility of the proposed backplane circuit strategy in production line. It is rational to believe that our strategy may offer a good avenue to upgrade traditional ITO and Cu materials for developing high-performance displays in scale production.

International audience; Etching residues of crystallized indium tin oxide (ITO) films deteriorate thin-film transistor (TFT) characteristics and negatively affect the display images. The usability of active-matrix displays is inseparable from hydrogenated amorphous silicon (a-Si:H) TFT backplanes. In particular, in large-area displays, reducing the overlap area of gate and source lines can reduce crosstalk capacitance, resulting in uneven color defects. In this study, orthogonal design is established to optimize deposition parameters of amorphous ITO films. Low-power and high-water-vapor flow during sputter deposition can effectively suppress ITO crystallization and etching residue formation. A TFT with an optimized ITO film presents the best electrical performance and affords images free from brightness variations and streak defects in the display backplane, i.e., ITO-s3 exhibits a superior ΦH of 1.954 × 10−2 Ω−1 within the range of (0.028–1.974) × 10−2 Ω−1. This allows us to propose a deterioration mechanism of TFT characteristics, as follows: (1) ITO residues increase the internal stress of the gate layer and deteriorate the TFT characteristics; (2) ITO residues lead to cracks and voids in the SiNx dielectric and act as carrier traps. The results of this work offer an avenue to develop advanced large-area displays applicable in vehicles in light of taking full advantage of existing equipment.

International audience; The Cenozoic history of the Tibetan Plateau topography is critical for understanding the evolution of the Indian-Eurasian collision, climate, and biodiversity. However, the long-term growth and landscape evolution of the Tibetan Plateau remains ambiguous, it remains unclear if plateau uplift occurred soon after the India-Asia collision in the Paleogene or later in the Neogene. As the landscape evolution is controlled mainly by mountain uplift and surface processes, the present-day river profiles and the drainage basin geometries preserve important information that can be extracted to infer the long-term history of mountain uplift with numerical models. Here we focus on the southeastern Tibetan Plateau where three of the world’s largest rivers draining the Tibetan Plateau (the Yangtze, Mekong, and Salween Rivers, i.e., Three Rivers) have incised deep valleys with distinctive geomorphic signatures. We reproduce the uplift history of the southeastern (SE) Tibetan Plateau using a 2D landscape evolution model, which simultaneously solves fluvial erosion and sediment transport processes in the drainage basins of the Three Rivers region. Our model was optimized through a formal inverse analysis with a large number of forward simulations, which aims to reconcile the transient states of the present-day river profiles. The modeling results were ultimately compared to existing thermochronologic and paleoelevation datasets to help decipher between competing tectonic models that predict contrasting topographic evolutions. Our results suggest initially low elevations during the Paleogene, followed by a gradual southeastward propagation of topographic uplift of the plateau margin until present day. Our modeling thus does not support Paleogene formation of the SE Tibetan Plateau with a major subsequent degradation via upstream fluvial erosion. The quantitative constraints on landscape evolution achieved based on drainage patterns in SE Tibet indicate a powerful tool potentially applicable to other regions to infer important implications for the evolution of Indian-Eurasian collision, Asian monsoons, and biodiversity, as well as the geodynamic forces involved in collisional orogens.

International audience; With the service-oriented encapsulation of Internet of Things (IoT) devices, IoT services, which are functionally compatible and non-functionally satisfiable, are composed to support domain applications. The execution of IoT services may last for a relatively long time duration in which their capacities may vary significantly. In this setting, whether or not, and to what extent, certain constraints specified upon certain IoT services can always be satisfied during their execution, are to be explored. This observation motivates us to formalize the interpretation of qualitative and quantitative satisfaction for prescribed constraints, and thus, to conduct IoT service monitoring at runtime. Specifically, the requirement of IoT service monitoring is formulated as a constraint satisfaction problem. Specification-based monitoring is developed leveraging Signal Temporal Logic (STL), where a novel accumulative robustness metric, denoted Accumulative STL (ASTL), is proposed to emphasize the robust satisfaction over the entire time domain. Hence, an ASTL-based mechanism is proposed to support IoT service monitoring, where prescribed constraints are converted to ASTL formulae, and interpreted with qualitative and quantitative semantics at runtime. Case studies and extensive evaluations are conducted upon publicly-available datasets. Experimental results show that ASTL performs better than the state-of-the-art techniques with more robust satisfaction.

The analysis of folds within pebbles in conglomerates has been used to infer deformation events before deposition of the conglomerate. However, it is not clear whether folds can develop within pebbles during subsequent conglomerate deformation. We use numerical modelling to investigate folding within internally layered pebbles in a ductile deformation regime and simple shear deformation. We vary the initial orientation and rheology of the layers within pebbles, as well as the relative rheology of the conglomerate matrix, for single isolated pebbles and multiple interacting pebbles. We use a power-law viscous rheology for both the pebbles and their matrix. Folding within pebbles can indeed occur, but only within a narrow range of initial layer orientations, strength or viscosity ratio between the internal layers and that of the matrix relative to the pebble layers. Results are used to interpret the strongly deformed conglomerates from the Proterozoic Hutuo Group in the Wutai Mountains, North China Craton, that contain a small percentage of pebbles with internal folds. Based on field observations and numerical modelling results, we suggest that these formed during deformation of the conglomerate and do not represent inclusion of previously folded lithologies into the unit., Fieldwork by HR in the Wutai Mountains area, China was supported by the China Geological Survey (grant No. 12120114076401). Fieldwork by PDB was kindly supported by the Chinese University of Geosciences (Beijing). We appreciate the help for the fieldwork from Zhongbao Zhao, Changshun Wen, Chao Li and the constructive suggestions from Guoli Yuan and Zhongbao Zhao. HR thanks the financially support by the China Scholarship Council (CSC; No. 201506400014) and the China Geological Survey (grant No. DD20190465). EGR acknowledges funding by the Spanish Ministry of Science, Innovation and Universities (“Ramón y Cajal” fellowship RYC2018-026335-I). M.-G.L acknowledges the support of the Juan de la Cierva programme of the Government of Spain's Ministry for Science, Innovation and Universities (grants FJCI-2015-2417 and IJC2018-036826-I).

International audience; A free-standing nanostructured boron-doped diamond (BDD) electrode was fabricated by reactive ion etching (RIE) with oxygen plasma. The free-standing architecture and nanowires endowed the BDD electrode with high specific capacitance and good stability. As a result, the BDD nanowires electrode etched for 60 min (BDD-NWs-60) featured the best capacitive performance with a specific capacitance of 24.9 mF cm−2 at a scan rate of 10 mV s−1 and capacitance retention of 90% after 6,000 cycles at a constant current density of 1.0 mA cm−2. Furthermore, a symmetric capacitor device was assembled using two BDD-NWs-60 electrodes, the device exhibited the highest energy and power densities of 0.41 mJ cm−2 and 0.79 mW cm−2, respectively. For a practical application, three BDD-NWs-60//BDD-NWs-60 symmetrical capacitors in series could light a red LED and rotate a homemade fan. Based on the above satisfactory behavior of the BDD electrode, the influence of the RIE process on the capacitive performance of the BDD electrode was proposed.

International audience; In deep-sea slope areas, canyons provide an ideal space to preserve sediments and provide a window to explore the deepwater deposition process, such as turbidity flow and contourite currents. We have evaluated results of the study of the northern continental slope of the South China Sea characterized by the presence of mostly straight canyons. After evaluating core samples and interpreting the corresponding seismic data, we static the sedimentary parameter and identified two types of canyons with different migrating trajectories: "convex downward curve-shaped" trajectories and "convex upward curve-shaped" trajectories. The convex downward curve-shaped canyon trajectory is distinguished by a lower layer of coarse-grained sediment and an upper layer of fine-grained sediment, whereas the convex upward curve-shaped canyon trajectory features a lower layer of fine-grained sediment and an upper layer of coarse-grained sediment. Combining the grain size of the core sample and the scale of the sedimentary structure, we restore the turbidity flow rates and the corresponding turbidity flow behaviors. Coarse-grained turbidity flows are characterized by lower vertical erosion rates and higher lateral abrasion rates, whereas fine-grained turbidity flows exhibit the opposite characteristics. Thus, the convex downward curve-shaped migration trajectory is mainly formed by coarse-grained turbidity flow erosion in the first stage (the late migration stage) and fine-grained turbidity flow deposition in the second stage (the vertical aggradation stage). In contrast, the convex upward curve-shaped trajectory forms through the opposite pattern of sedimentary evolution.

International audience; The wide-adoption of edge computing promotes the scheduling of tasks in complex requests upon smart devices on the network edge, whereas tasks are necessary to be offloaded to the cloud when they are intensive in computational and energy resources. Traditional techniques explore mostly the scheduling of atomic tasks, whereas complex requests scheduling on edge servers is the challenge unexplored extensively. To address this challenge, this paper proposes an online task scheduling optimization for DAG-based requests at the network edge, where this scheduling procedure is modeled as Markov decision process, in which system state, request and decision space are formally specified. A temporal-difference learning based mechanism is adopted to learn an optimal tasks allocation strategy at each decision stage. Extensive experiments are conducted, and evaluation results demonstrate that our technique can effectively reduce the system's long-term average delay and energy consumption in comparison with the state-of-art's counterparts.

International audience; With the rapid development and massive deployment of the Internet of things (IoT) networks, security related issues in the IoT networks have been paid more and more attention to. Among all the security concerns, message authentication is critical in preventing the unauthorized messages from being transmitted in the IoT networks. Many message authentication schemes have been proposed based on the public-key cryptosystem, where the key management is simple and scalable. Identity based cryptosystem is a special type of public-key cryptosystem and can further ease the process of the key management since the public keys can be obtained easily. In this paper, we devise an efficient message authentication with enhanced privacy (IMAEP) scheme using the identity based signature. Our proposed scheme can provide both unconditional privacy as well as the enhanced privacy under full key exposure attack. Our proposed scheme can also provide existential unforgeability under the adaptive chosen-message-and-identity attack. Compared with the scheme that has the same level of anonymity and security, our proposed scheme has much lower computational overhead, and can provide extra unconditional privacy. Next we propose an extended IMAEP (EIMAEP) scheme for the general access structures where the message is signed by a group of users instead of one user. We also conduct comprehensive analysis and demonstrate that the EIMAEP scheme can achieve the same level of privacy and unforgeability as the IMAEP scheme.

International audience; Here we combined microcalorimetry, enzyme activity measurements, and characterization of metal form in order to evaluate the effect of metal(loid)s on the activity of microbial community inhabiting tailings area with high toxic metal(loid)s concentration. Chromium (Cr), nickel (Ni), copper (Cu) and manganese (Mn) were the main pollutants. The exchangeable fractions (bioavailability) of Cu, Ni and Mn were higher in the tailings sample (Site Z), indicating a higher environmental risk. The total heat Qtotal (17,726.87 J/g), peak power Ppeak (541.42 μW/g) and growth rate constant k (0.11 h−1) of Site Z were higher than that of the polluted soil around tailings (Site Y). Such observation may be explained by physiological changes within the microbial community in response to high levels of heavy metal stress, thereby increasing respiration and improving microbial activity. In contrast, enzyme activities and enzyme activities index (GmeA) of Site Z were lower than the Site Y, which is strongly influenced by changes on physical-chemical properties (TN and TOC) and the presence of Cr, Mn, and Ni. Correlation coefficient and principal component analysis (PCA) indicate that GmeA is significantly correlated (p < 0.05 or p < 0.01) with environmental factors (EC, TOC and TN), Mn and Ni concentration, Ni bioavailability, and peak time (Tpeak). Therefore, GmeA represents a potential biological indicator for reporting the pollution degree in tailings area. Our results provide a theoretical basis for the prevention and control of pollution in non-ferrous metal(loid) tailings area

International audience; Organic mudstone can be a high-quality source rock in petroleum basins. The accumulation patterns of various types of mudstone can also serve as a useful record of paleogeography. Due to the impact of tectonic movements, the East China Sea Basin (ECSB) saw its deposition setting transform from closed-lacustrine to open marine settings. This provides an opportunity to explore organic matter accumulation patterns within such a transformation setting. This study classified the constituent mudstones according to their differences in composition and sedimentary structure as follows: coaly mudstone or carbonaceous mudstone, calcareous mudstone, clayey mudstone, and siliceous mudstone. Considering the different sedimentary structures, siliceous mudstone can be subdivided into laminated, wavy, and slumped mudstones. Using integrated multiple indices of the paleo-environment, which includes clay mineral content, trace mineral content, and micro-paleontology assemblages, we reconstructed the paleography setting during the Paleocene and inferred that during this time, the ECSB was characterized by sedimentary differentiation. We discerned two different organic mudstone accumulation patterns by combining the results from rock-eval pyrolysis and paleo-environmental indices: 1) A closed-lacustrine mudstone accumulation pattern characterized by abundant sediment supply and dominated by allogenous mudstone formation by the flocculation process. The fresh to slightly salty water environment provided adequate nutrition to microorganisms and an appropriate temperature led to the increased accumulation of type II1 and II2 kerogen. 2) An open-marine mudstone accumulation pattern which revealed a sediment-starved setting. The flocculation process and fine-graded turbidities were the main processes leading to mudstone accumulation. More plants were concentrated in shallow water with declining salinity, leading to peat and mass carbon mudstone accumulation.

International audience; Elevated concentrations of rare earth elements and yttrium (REE + Y) in acid mine drainage (AMD) attract worldwide attention. However, the source and control of REE + Y distribution patterns in AMD remain unclear. Water, rock, sediment, and sludge samples were collected from an ion-adsorption deposit site to investigate REE + Y concentrations and distributions. The heavy REE (HREE)-enriched patterns of the AMD resulted from preferential desorption of HREE in the clay-rich sediment strata, from which the REE + Y were ion-exchanged by an in-situ underground leaching process using ammonium sulfate brine. Free ions and sulfate complexes preserved REE + Y patterns and facilitated REE + Y mobility in the AMD leachate system. High concentrations of REE + Y occurred in the AMD, and decreased progressively through nitrification-denitrification and coagulation-precipitation procedures in a water treatment plant. Concentrations of REE + Y were one to three orders of magnitude higher in AMD than those in groundwater, and were negatively correlated (r2 = −0.72) with pH (3.8 to 8.7), suggesting that an acid desorption from minerals contributed the REE + Y to the AMD from the source rock. Normalized REE + Y patterns showed enrichments of HREE over light REE (LREE) and negative Ce anomaly. The distribution patterns were relatively constant for all water samples, despite their huge difference in REE + Y concentrations. This suggested a limited impact of preferential precipitation of LREE over HREE on REE + Y fractionations during neutralization. The potentially recoverable LREE and HREE were calculated to range between 1.12 kg/day and 3.37 kg/day, and between 1.29 kg/day and 3.76 kg/day, respectively. The findings reported in this study lend promise for efficient REE + Y recovery from AMD

International audience; High-elevation, low-relief surfaces are widespread in many mountain belts. However, the origin of these surfaces has long been debated. In particular, the Southeast (SE) Tibetan Plateau has extensive low-relief surfaces perched above deep valleys and in the headwaters of three of the world’s largest rivers (Salween, Mekong and Yangtze). Synthesized low-temperature thermochronologic data indicate that uplift of the Tibetan Plateau may have propagated progressively from NW to SE, with thermochronologic ages at ~50 Ma observed in the headwaters and interfluves of the rivers but young ages

This is a poster presented at the 2022 American Geophysical Union annual meeting (December 12-16). It summarizes Shobe et al. (2022; Basin Research). Abstract: One way to decipher the stratigraphic record to reveal information about surface processes is through inverse analysis using forward models. In this approach, a forward surface process model that generates stratigraphy is run many times with varying parameter values, and the output stratigraphy is compared against observations. The parameter values that generate best-fit stratigraphy may then tell us something about surface processes. Inverse analysis of forward models is often used to infer past forcings to landscapes, but it can also be used to make inferences about process dynamics. We use inverse analysis of forward models to ask: How should we model seascape evolution and the development of passive margin stratigraphy over geologic time? Understanding the evolution of passive margins is essential because they contain Earth’s longest and most complete records of landscape change on adjacent continents. Yet there is as yet no consensus about the process representations that should make up a simple but complete seascape evolution model. Should margin evolution be governed by processes where downslope sediment flux depends only on local slope? Or should nonlocal processes where sediment flux depends on factors other than local slope, such as the history of slopes experienced along a transport pathway, play a major role? We conduct a data-driven inversion exercise using seven stratigraphic sections from the Southeast Atlantic Margin to assess the importance of nonlocal transport processes to building passive margin stratigraphy. We compare two mathematical models for seascape evolution: one that is purely local and one that incorporates nonlocal transport. The two models can converge through parameter changes alone, such that data-driven inversion can determine quantitatively the optimal process representation. Producing observed stratigraphy requires significant contributions from nonlocal processes like slope bypass and long-distance sediment transport; this result is true regardless of whether only the modern bathymetry or the full stratigraphic record is used to constrain the inversion. Results suggests that nonlocal processes dominate the development of passive margin stratigraphy and are essential ingredients in models used to infer past landscape dynamics from the stratigraphic record.

The extremely thick sedimentary sequence in the Qaidam Basin, northeastern Tibetan Plateau (TP) is closely related to the uplift of the TP. Due to the scarcity of minerals that can be dated continuously, little is known about the isotopic responses of the minerals in this area to the changes in the weathering and sources over a long time period. A 938.5-m long core (magnetostratigraphic age of ∼ 2.8–0.1 Ma) was drilled in the western Qaidam Basin in 2008. The mineralogy and isotopic compositions of gypsum in this core were investigated. The gypsum recorded the primary information about the brine that formed during ∼ 2.8–0.1 Ma. The variations in the Sr isotopes (0.709817–0.714473, average of 0.711249) and Nd (0.512114–0.512614, average of 0.512184) of the gypsum samples suggest that the weathering products of the rocks in the Kunlun and Altyn mountains (Mts) likely exerted a strong control on the Sr-Nd isotopes of the lakes. The climate and the Sr content/isotopic compositions of the gypsum samples were affected by the regional tectonic activities throughout the evolution of the paleolake since 2.8 Ma. The results of this study demonstrate that Sr-Nd isotopes are useful tools for investigating the origins of evaporite deposits and the interactions between tectonic activities and climate change.

International audience; Butyl Xanthate (BX) is a typical flotation reagent used to extract non-ferrous nickel ores, discharged into the surrounding environment of mining areas in large quantities. However, few studies have focused on the toxicity of combined pollution of BX and nickel (Ni) on aquatic plants, especially phytoplankton, the main producer of aquatic ecosystems. The toxicity and potential mechanism of single and combined pollution of BX and Ni at different concentrations (0–20 mg L−1) on typical freshwater algae (Chlorella pyrenoidosa) were studied. BX slightly stimulated the growth of C. pyrenoidosa on the first day, but Ni and Ni/BX mixture significantly inhibited it during incubation. Results showed that the inhibition rate (I) of the pollutants on the growth of C. pyrenoidosa followed the order: Ni/BX mixture > Ni > BX. The 96-h 20% effective inhibitory concentrations (96h-EC20) of Ni and BX on C. pyrenoidosa growth were 3.86 mg L−1 and 19.25 mg L−1, respectively, indicating C. pyrenoidosa was sensitive to pollutants. The content of total soluble protein (TSP) and chlorophyll a (Chl-a) changed significantly, which may be caused by the damage of pollutants to cell structures (cell membranes and chloroplasts). In addition, the I of pollutants on C. pyrenoidosa growth was related to dose, superoxide dismutase (SOD), catalase (CAT) and malondialdehyde (MDA). The increasement of reactive oxygen species (ROS), antioxidant enzymes (SOD and CAT), and MDA content, suggested C. pyrenoidosa suffered from oxidative stress, leading to lipid oxidation. These results will help to understand the toxicity mechanism of pollutants in typical mining areas and assess the environmental risks of pollutants to primary producers in aquatic ecosystems

International audience; Microbes are important component in terrestrial ecosystem, which are believed to play vital roles in biogeochemical cycles of metalloids in mining and smelting surroundings. Many studies on microbial diversity and structures have been investigated around mining and smelting sites, whereas the ecological processes and co-occurrence patterns that influence the biogeographic distributions of microbial communities is yet poorly understood. Herein, microbial biogeography, assembly mechanism and co-occurrence pattern around mining and smelting zone were systematically unraveled using 16S rRNA gene sequencing. The 66 microbial phyla co-occurring across all the samples were dominated by Proteobacteria, Chloroflexi, Acidobacteria and Crenarchaeota. Obvious distance-decay (r = 0.3448, p < 0.001) of microbial community was observed across geographic distances. Differences in microbial communities were driven by the joint impacts of soil factors, spatial and metalloids levels. Dispersal limitation dominated the microbial assemblies in whole, SC and GX sites while homogeneous selection governed that in YN site. The changes in pH and Sb level significantly influenced the deterministic and stochastic processes of microbial communities. Network analysis suggested a typical module distribution, which had apparent ecological links among taxa in modules. This study provides first insight of the mechanism to maintain microbial diversity in metalloids-laden biospheres.

International audience; The collaboration of contiguous Internet of Things (IoT) devices is envisioned to satisfy complex applications which are beyond the capacity of single devices. The functionalities of IoT devices are encapsulated as IoT services, and their collaboration is implemented in terms of IoT service composition. Considering the capacity occupancy, release, and consumption caused by the implementation of IoT services, their composition is challenging in capacity-dynamically fluctuating IoT networks. This paper proposes a dynamic IoT service composition mechanism with inter-service dependencies adopted to capture the dynamic changes of IoT devices, and this change is specified by various Quality-of-Service factors. IoT service composition is formalized under Computation Tree Logic specification with certain composite structures and dynamic dependencies, and this composition is formally achieved by an optimized model checking method. Extensive experiments are conducted on publicly available datasets, and evaluation results show that our technique outperforms the state-of-the-art's approaches in relevant performance metrics.

International audience; The science teams of Moderate Resolution Imaging Spectroradiometer (MODIS) and Visible Infrared Imager Radiometer Suite (VIIRS) have been supporting various global climate, biogeochemistry, and energy flux research efforts by producing valuable long-term Leaf Area Index (LAI) products. Although intensive LAI validation studies have been carried out globally, retrieval accuracy has been assessed only over short time spans and product quality is reported as a constant based on the assumption that it is stationary. However, a preliminary evaluation found a time-dependent signal degradation of the MODIS sensors which may cause the uncertainty of the Bidirectional Reflectance Factor (BRF) product to exceed the preset uncertainty buffer in the retrieval algorithm and result in MODIS LAI quality variation and time-series inconsistency with VIIRS LAI. Therefore, to ensure the reliability of trend-detection studies and to answer the critical question of whether the algorithm configuration is still suitable for the uncertainty level of present BRF product, there is a need for a more comprehensive investigation regarding the performance stability of LAI retrieval algorithm due to model uncertainty and input uncertainties. This paper reports analyses of inter-annual stability and trends of LAI uncertainties (inferred from product quality flag rather than ground-based validation) as well as LAI magnitudes using multi-year (MODIS: 2001–2019, VIIRS: 2013–2019) and multi-site (445 sites) datasets. We found that the quality metrics of the two products are consistent across different biome types and LAI values (R2 ranged from 0.88 to 0.99). In the 19-year MODIS period, we found a significant increasing trend in LAI magnitudes (4.5%/decade) which agrees with previous reports, while there was no significant trend in product quality. Moreover, quality metrics showed much smaller inter-annual variations than LAI values, which confirms the performance stability of retrieval algorithms and suggests that the configuration of MODIS algorithm is still compatible with the uncertainty of algorithm inputs. Additionally, this study provides support to the “Greening Asia” studies by eliminating the possibility that the “greening” could be attributed to artificial trends caused by sensor degradation. We also found very small inter-annual variations in atmospheric conditions (e.g., cloud and aerosols), which further assures that the performance stability of retrieval algorithm. Overall, our results demonstrate the robustness of the retrieval algorithm in the presence of changes in input uncertainties. The temporal stability of the algorithm performance indirectly strengthen the confidence in the continuous use of MODIS LAI products either independently or in combination with its successor - VIIRS LAI - to study global and regional vegetation dynamics

International audience; The fading of organic dyes is a serious challenge for conservation of art works. Inspired by the ancient Maya blue pigment, a hybrid pigment of halloysite (Hal) and alizarin (AZ) was prepared by adsorption in aqueous solution. In addition, a layer of polyorganosilane (POS) is used to cover the surface of the hybrid pigment to enhance the chemical resistance and photostability. The hybrid pigments were characterized by X-ray diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy and thermal analysis. The adsorption behavior of AZ onto Hal was investigated and optimized. AZ-Hal hybrid pigment was prepared at pH = 9. Chemical stability was checked by 1 mol/L HCl, 1 mol/L NaOH and ethanol attack. Photostability was evaluated by exposing the pigment to visible light for 360 h, which is equal to more than 28 years in a common museum. AZ molecules were adsorbed on the external and/or internal surface via physical adsorption and hydrogen bonds. The presence of POS in the hybrid pigment influences positively the chemical and light resistance. This may be due to the protective layer that isolates sensitive dyes and oxidising agents.

International audience; The increasing demands for oil and gas and associated difficult drilling operations require oil-based drilling fluids that possess excellent rheological properties and thermal stability. The objective of the present work was to investigate the rheological properties and thermal stability of organo-montmorillonite (OMnt) modified with various surfactants and under various loading levels in oil-based drilling fluids, as revealed by the interaction between organic surfactants and montmorillonite. The influence of the structural arrangement of surfactants on the thermal stability of organo-montmorillonite (OMnt) in oil-based drilling fluids was also addressed. OMnt samples were prepared in aqueous solution using surfactants possessing either a single long alkyl chain two long alkyl chains. OMnt samples were characterized by X-ray diffraction, high-resolution transmission electron microscopy, thermal analysis, and X-ray photoelectron spectroscopy. Organic surfactants interacted with montmorillonite by electrostatic attraction. The arrangements of organic surfactants depended on the number of long alkyl chains and the geometrical shape of organic cations. In addition to the thermal stability of surfactants, intermolecular interaction also improved the thermal stability of OMnt/oil fluids. A tight paraffin-type bilayer arrangement contributed to the excellent rheological properties and thermal stability of OMnt/oil fluids. The deterioration of rheological properties of OMnt/oil fluids at temperatures up to 200°C was due mainly to the release of interlayer surfactants into the oil.

International audience; The northwestern South China Sea (NW-SCS) presents a spatial-temporal evolution of its source-to-sink (S2S) system, that recorded the movement of the Indochina block and the collision between the Indian and Eurasian plates. However, complex tectonic movements and topographic evolution have led to controversial studies about the spatial-temporal distribution of allogenic materials and autogenic sediments. In this study, we integrated a number of multiscale data to review the S2S system evolution of the northwestern area of the South China Sea from the Eocene to the Miocene. The series include the initial synrift, postrift and thermal subsidence stages. First, we identified the major sediment pathways using seismic profile interpretation. We reconstructed the sediment distribution and lithofacies association within the dispersal sink area based on seismic data, core samples and grain-size analysis. We quantitatively studied the sediment flux and catchment area based on mass balance calculation modeling. Following this, we acquired rare-earth element (REE) data and zircon U–Pb age data from the bedrocks of the continental blocks and the South China Sea Cenozoic basement and rivers in the NW-SCS area to restore the provenance area and evaluate the migration distance by inspecting the heavy mineral assemblages. According to the above studies, three phases of S2S dynamics were identified. 1) The initial rifting stage occurred during the Eocene, and active rifting in the South China Sea induced a major topographic change. A large amount of autogenic slump sediments and a smaller amount of paleo-Red River sediments were injected into the Beibu Gulf Basin (BBGB) and the Yinggehai-Song Hong Basin (YGHB). 2) The postrift stage occurred during the Oligocene. Regional uplift and tectonic inversion probably linked to the clockwise rotation of the Indochina Block, broke the connection between the Beibu Gulf Basin and the Red River catchments. The paleo-Qin River and the paleo-Lian (Nanliu) River brought a large amount of clastic material into the Beibu Gulf Basin from the Cathaysia Block. 3) The thermal subsidence stage occurred during the Miocene: the eastward topographic tilt was enhanced, and the drainage basin entered postrift stage. The development of the Paleo-Red River and its branches, the Lam River and the Ma River, brought distal sediment into the YGHB, while the rivers in the west Cathaysia Block transported sediment into the BBGB. Statistical analysis of the S2S system parameters suggests that the average terrain altitude played a dominant role in determining the S2S system volume during the Eocene, while the dominant role transferred to the sediment supply during the Oligocene and Miocene.

International audience; The collaboration of Internet of Things (IoT) devices promotes the computation at the network edge to satisfy latency-sensitive requests. The functionalities provided by IoT devices are encapsulated as IoT services, and the satisfaction of requests is reduced to the composition of services. Due to the hard-to-prediction of forthcoming requests, an adaptive service configuration is essential, when latency constraints are satisfied by composed services. This problem is formulated as a continuous time Markov decision process model constructed with updating system states, taking actions and assessing rewards constantly. A temporal-difference learning approach is developed to optimize the configuration, while taking long-term service latency and energy efficiency into consideration. Experimental results show that our approach outperforms the state-of-art's techniques for achieving close-to-optimal service configurations.

International audience; This study investigated the performance and microbiome of cyclic denitrification filters (CDFs) for wood and sulfur heterotrophic-autotrophic denitrification (WSHAD) of saline wastewater. Wood-sulfur CDFs integrated into two pilot-scale marine recirculating aquaculture systems achieved high denitrification rates (103 ± 8.5 g N/(m3·d)). The combined use of pine wood and sulfur resulted in lower SO42− accumulation compared with prior saline wastewater denitrification studies with sulfur alone. Although fish tank water quality parameters, including ammonia, nitrite, nitrate and sulfide, were below the inhibitory levels for marine fish production, lower survival rates of Poecilia sphenops were observed compared with prior studies. Heterotrophic denitrification was the dominant removal mechanism during the early operational stages, while sulfur autotrophic denitrification increased as readily biodegradable organic carbon released from wood chips decreased over time. 16S rRNA-based analysis of the CDF microbiome revealed that Sulfurimonas, Thioalbus, Defluviimonas, and Ornatilinea as notable genera that contributed to denitrification performance.

The pyrolysis process of oil shale is significantly affected by atmospheric conditions. In this paper, the pyrolysis experiments of oil shale under non-isothermal conditions are carried out using nitrogen and carbon dioxide as heat-carrying fluids. The results show that the activation energy of the second stage of oil shale pyrolysis under carbon dioxide is less than that under nitrogen. The thermodynamic analysis of the second stage of oil shale pyrolysis shows that Gibbs free energy, activation enthalpy and activation entropy are higher under carbon dioxide than those under nitrogen, which obeys the law of carbon dioxide promoting oil shale pyrolysis. In addition, the volatile release characteristics of oil shale in the second stage of pyrolysis were analyzed, which proves that the volatile release characteristics of oil shale under carbon dioxide are higher than that under nitrogen. Therefore, carbon dioxide is helpful to promote the pyrolysis of oil shale and increases the release of volatile substances during pyrolysis.

International audience; Pearl River Mouth Basin (PRMB) is a typical episodically rifting basin, and its sediment records exhibit a multistage infilling process. To build the coupling relationship between the spatial variability of tectonic movement and sediment dispersal pattern, we character the source-to-sink system distribution within continental margin and analysis their dominated factors with quantitative statistical methods. First, we identify the faults and calculate the rifting rate by interpreting the two-dimensional (2D) seismic data and zircon or apatite fission-track data (ZFT/AFT). Accordingly, based on the various trending of the rifting rate evolution, we classified rifting process episodically into three patterns: accelerated rifting decelerated rifting, and uniform rifting. Then, we integrated the data available on detrital zircon U–Pb, rare earth element, and heavy mineral assemblage to identify the responding S2S components associated with the above various rifting processes. Results show that in the first tectonic stage during the early Eocene, the sediments were mainly sourced from an intrabasin provenance area, whereas in the late Eocene to the Oligocene, the paleo-Pearl River provided the sediments to the sink area. We restore the facies association of the sink area by studying the core samples, electric well logs, and three-dimensional (3D) seismic data. During the accelerated and uniform rifting processes, coarse-grained deposited along the boundary faults, which includes the fan delta and subaqueous fans. During decelerated rifting, the depositional environment was dominated by braided channels, meandering channels, and tide-influenced channel accretion. Based on the quantitative analysis the relationship between the grain size of the sediment in each S2S segment and the rifting rate, more fine-grained components were preserved in the decelerated rifting system, while coarse-grained sediments fill the accelerated rifting depression and uniform rifting components. Furthermore, the sediment supply and relative height can influence the volume of the S2S system in the uniform rifting system. In the decelerated rifting basin, the sediment supply is the major factor associated with the development of S2S, whereas the relative height is the major factor associated with the accelerated rifting basin.

International audience; Structural transfer zones in a half‐graben rift basin play a significant role in controlling the sandy sediments and provided a target to the hydrocarbon exploration. Previous studies have classified the transfer zone in lacustrine environments into two different patterns: synthetic approaching transfer zones and synthetic overlapping transfer zones. However, the depositional pattern evolution and control factors of the above transfer zones are still unclear. In the Fushan Sag, the northern South China Sea, an overlapping transfer zone developed in the early Eocene Epoch, while a synthetic approaching transfer zone developed in the late Eocene due to tectonic uplift. This evolution process provided an opportunity to study the stack pattern of strata architectural variability and facies distribution in the structural transfer zone of the Eocene lacustrine basin. In this study, as the oriented sedimentary structures in core samples and heavy mineral assemblages of 18 wells indicating, we rebuilt the paleo‐hydrodynamic distribution evolution during the early and late Eocene. Then, we divide the sequence‐stratigraphy and calculate the sand body parameters according to the seismic data and well log interpretation. During the early Eocene, the lake level was in the low stand, and the faults broken displacement in the East block was over 50 m. We point out that the prograding delta and turbidities are oriented perpendicular to the structural transfer zone. According to the quantitative analysis of the flow rate and the depositional parameters, we speculate that its gravity transported the sediment and the sediment‐supply is dominated factors during this period. Up to the late Eocene, the rising lake level and the decreased faults displacement lead the flow diverted to a NE‐direction, resulting in it being parallel to the axis of the transfer zone. Thus, we speculated that the accommodation space is domination in this period. In comparison, the above two periods, a braid river delta with an isolated sand body and turbidities developed in the deep area is prominent in the overlapping transfer zone, while a meandering river delta characterized in the synthetic approaching transfer zone.

International audience; The Bohai Bay Basin, a typical intracontinental rift basin, records East Asia's kinematic plate history during the Cenozoic. The rifting process was driven by the counterclockwise rotation in the direction of the Pacific Plate subduction. From the early Eocene to the Oligocene, the rifting process can be divided into three stages: extension initiation, peak extension, and post-extension. The corresponding rifting rate was calculated based on 40Ar-39Ar data. Then, the provenance area evolution of the above three rifting stages was established by combining the detrital zircon U–Pb data and heavy mineral assemblage data (ZTR, GZi, and ATi). According to the results calculated by 40Ar/39Ar analysis, the topography of the sink area in the western Bohai bay basin was characterized by moderately rising subsidence rates (100 m/Ma) during the extension initiation stage (Paleocene-Early Eocene), when surface drainage was restricted to a limited area with steep channel slopes. During this stage, referring to the core description and seismic interpretation results, the fan delta distributes most of the sediment, most of which migrates from the proximal region. Until the peak extension stage, the source-sink system develops as the rate of subsidence increases (200 m/Ma), making the sink area larger, and this period involves multiple types of pathways, including synsedimentary faults and erosional valleys. Sediments from Taihang Massif and Jiaoliao Massif infill the subsidence zone at the distal end. Then, in the post-extension stage, the source-sink systems involve a multi-provenance area (i.e., sourcing from both proximal and distal areas), a large sink area, and a gentle channel gradient due to a decrease in subsidence rate (60–80 m/Ma). Catchment relief, sediment migration distance, and average fault displacement were used, and these parameters were related to the sediment supply (Qs) for the three rifting stages. We find that during extension initiation and peak extension, the source-to-sink systems show a high amount of sand influx (Qsand/) and that the ratio Qsand/Qs total shows a proportional relationship with catchment relief and average fault displacement; this relationship is inversely proportional to the catchment-unit area. Also, according to the types of pathways, we classified the source-to-sink systems during this period into three types, steep eroded pathway (Type-I S2S), gentle slope developed with several boundary faults (Type-II S2S), steep slope with observably eroded valleys or fault-troughs (Type-III S2S). The ratio of Qsand/Qs is only related to the sediment migration distance and average fault displacement in the post-extension stage. Besides the above three types of source-to-sink systems, we found that multi-stage faults developed along the slope (Type-IV S2S) predominated during this stage.