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Growth and phosphorus uptake of micropropagated southern highbush blueberry plants inoculated with ericoid endophytic and mycorrhizal fungi in varied growth substrates
No full textInternational audiencePhosphorus (P) acquisition and use by southern highbush blueberry Vaccinium corymbosum L. plants is critical during early stages of development and impair root development, especially for growth substrates with poor nutrient contents. However, inoculation of blueberry plants with ericoid mycorrhizal fungi (ErMF) or dark septate endophytes (DSE) can improve P during the plants acclimation stages and reduce plant mortality, especially in dry northern Mediterranean climate conditions. Herein, we grew southern highbush blueberry micro-cuttings in conditions without inoculation (control) or in inoculated with four strains: two Ericoid mycorrhizal sp. (D01), and (C01), E. endophyte (C31), and Phialocephala fortinii Wang & Wilcox in sandy (S), fresh field (FF), and FF+S soil mix substrates for 10 months before harvest. At harvest, root colonization levels, plant height, leaf area, the fresh matter of roots and shoots, root-to-shoot ratio, P content, and P utilization efficiency (PUE) were measured. We found that the root colonization levels were inhibited in the S for the different inoculated F treatments, owing to the elevated carbonate and salt concentrations present. The average P uptake responses from the different F inoculated strains were 52.2 %, 29.6 %, and 22.4 % in the S, FF, and FF+S substrates. Inoculation of blueberry plants with C31 strain exhibited the highest (59.1 %) P uptake average response, inoculation with P. fortinii strain showed the lowest (15.8 %) response. The root growth responses were inhibited in the FF+S (-0.2 %), increased in the S (8.4 %), and FF (6.2 %) substrates. Our findings therefore describe responses under controlled nursery conditions with single-strain inoculation and three substrate types. Because blueberry roots in the field are commonly co-colonized by multiple ericoid and endophytic fungi, interactions among partners may amplify or dampen the effects observed here; future work should test coinoculation consortia and validate performance under field conditions.</div
IPVS Consensus Statement on The Natural History of Cervical Human Papillomavirus Infection
No full textInternational audienceBackground: Changes in cervical type-specific human papillomavirus (HPV) detection may reflect both natural variation in detectability and recent infection or clearance.Methods: The Policy Committee of the International Papillomavirus Society (IPVS) convened a multidisciplinary working group to review scientific evidence and terminology related to the natural history of cervical type-specific HPV infections.Results: The group proposes an updated model that distinguishes 3 cervical states: no HPV infection, undetectable HPV infection, and detectable HPV infection. An undetectable HPV infection refers to either a state of low viral genome load below the cutoff of the assay used or to a particular state of viral latency. These 2 states are virtually indistinguishable, and viral latency remains a topic of ongoing research and debate. The transition from HPV not detected to HPV detected is consistent with several possible events, including (i) acquisition from a partner, (ii) autoinoculation, (iii) transition from undetected to detected HPV infection, and (iv) transient deposition of viral material. Conversely, the transition from HPV detected to HPV not detected is consistent with (i) viral clearance, (ii) transition from detected to undetected HPV infection, and (iii) inadequate sampling. The likelihood of each possible explanation depends on context, including screening history, exposure, age, and immune status.Conclusions: By distinguishing true cervical states from observed test results, the updated model acknowledges uncertainties that complicate the interpretation of HPV test result patterns in research and practice. Adopting this model may improve clarity and ensure consistency in scientific and clinical communication about cervical HPV infections
Comparative Analysis of Irradiation Technologies on High-Density Polyethylene (HDPE) for Biopharmaceutical Applications
No full textInternational audienceThe impacts of e-beam and X-ray irradiation on medical-grade high-density polyethylene (HDPE) are compared with that of gamma irradiation to evaluate their potential effects on pharmaceutical applications. An extensive suite of analytical techniques was employed to evaluate the chemical and physical transformations of irradiated HDPE. Key findings indicated that irradiation did not significantly alter the mechanical properties, as tensile strength and elongation at break remained stable across all irradiation types and doses. Thermal analysis via Differential Scanning Calorimetry (DSC) revealed a slight decrease in melting temperature at higher doses, with an equivalent melting temperature peak observed for all three irradiation technologies. Electron Spin Resonance (ESR) detected alkyl and allyl radicals, which decreased over time, showing no significant differences attributable to irradiation type or dose. Colorimetric analysis indicated yellowing in the samples, linked to specific additives. The quantification of methionine oxidized byproducts by High-Performance Liquid Chromatography (HPLC) demonstrated that the oxidation potential was equivalent for the three irradiation technologies for HDPE. The study concluded that there was a lack of significant impact of irradiation technologies on several physical, chemical and mechanical properties of HDPE
Flood pulse monitoring in wetlands with multi-temporal Sentinel-1 interferometric coherence data: Application to the Okavango Delta (Botswana)
No full textInternational audienceFlood-pulsed wetlands are characterized by significant seasonal water fluctuations, which play a critical role in the dynamics of these sensitive ecosystems. Among the growing number of existing remote sensing products, we explore the potential of interferometric (InSAR) coherence time series, derived from Sentinel-1 synthetic-aperture radar images, to characterize the hydrological dynamics of the Okavango Delta, a vast flood-pulsed wetland. Interferometric coherence reflects changes in surface conditions, making it a powerful tool for detecting flood propagation. By fitting harmonic functions, we produce parameters that quantify the seasonality of coherence time series with short isotemporal baselines (12 days). In particular, we developed a normalized seasonal index based on the ratio between the seasonal amplitude and the root-mean-square error of the fitted harmonic function, to map the seasonality of the coherence time series. A multi-annual analysis of coherence time series reveals a strong relationship between their seasonality, land cover, and flood frequency. Unsupervised clustering applied to statistical and seasonal metrics of coherence time series yields consistent classifications that map the variability of flood frequencies across wetland areas and clearly distinguish wetlands from dry zones. Similarly thresholds applied to normalized seasonal indices delineate the year-to-year extent of flood pulses with accuracy around 79 %. We show that coherence time series in never flooded areas exhibit a pronounced seasonal pattern driven by rainfall cycle, whereas this seasonality is disrupted by flood pulses in wetlands. Building on this, developed a change-detection approach to map the floods by identifying the date when coherence time series diverge from their seasonal pattern. The resulting flood arrival dates achieve 74–83 % accuracy compared to a reference dataset derived from optical data. Our results highlight the potential of coherence time series as a robust indicator of seasonal variations in inundation extent in flood-pulsed wetlands
The role of hydrogen sulfide and trisulfur radical ion in molybdenum transport by hydrothermal fluids: implications for porphyry-epithermal Cu-Au-Mo deposits
No full textInternational audienceKnowledge of the chemical speciation of molybdenum in fluids under hydrothermal conditions is key to understanding the formation of porphyry Cu-Au-Mo deposits, which are the primary economic source of copper, molybdenum and rhenium. However, the chemical identity and thermodynamic stability of aqueous complexes of molybdenum and the role of different ligands on Mo metal transport yet remain inconsistent and incomplete, in particular for sulfur-bearing fluids typical of such environments. We have experimentally studied the role of hydrogen sulfide (H 2 S and HS -) and the trisulfur radical ion (S 3 •-) in the transport of molybdenum by hydrothermal fluids at 300 °C and 500 bar as a function of pH, redox conditions as well as sulfur speciation and concentration. We combined solubility measurements of molybdenite in hydrothermal reactors using fluid quenching or sampling, with in situ synchrotron X-ray absorption spectroscopy experiments and thermodynamic and molecular modeling. Our solubility and spectroscopic dataset is consistent with the formation of the tetrathiomolybdate complex, MoS 4 2-, in reduced, H 2 S/HS --dominated fluids of neutralto-alkaline pH. In contrast, a mixed-ligand complex with three sulfide ions and one trisulfur radical ion, MoS 3 (S 3 ) -, prevails in more oxidized and more acidic fluids at the sulfide-sulfate transition where S 3 •-is far more abundant. In both complexes, Mo is nominally hexavalent and in a first-shell tetrahedral coordination with sulfur atoms. The derived equilibrium constants of the formal solubility reactions (log 10 K):MoS 2(s) + 2 H 2 S 0 (aq) + 0.5 O 2(g) = MoS 4 2-+ 2 H + + H 2 O (liq) and MoS 2(s) + H 2 S 0 (aq) + S 3 •-+ 0.5 O 2(g) = MoS 3 (S 3 ) -+ H 2 O (liq) , at 300 °C and 500 bar are 0.5±0.4 and 14.6±0.4, respectively. The solubility of MoS 2(s) predicted using these constants aligns well with Mo concentrations measured in natural fluid inclusions in quartz that record S-rich fluids from porphyry-epithermal systems. In contrast, other types of Mo complexes invoked so far (molybdates, alkali ion pairs, oxy-chlorides or oxysulfides) are negligible at such conditions. Thus, trisulfur radical ion complexes may be important carriers of Mo in hydrothermal fluids and would require further systematic investigation across a wide range of temperature and pressure.</p
Changes in Cooking and Breadmaking Properties of IR 841 Paddy Rice During Storage in West Africa
No full textInternational audienceTemperature and relative humidity can significantly affect quality of paddy rice during storage. Limited studies established the link between storage time, environmental fluctuations, changes in grain and flour physicochemical properties, and culinary performances. In a West African context, IR 841 paddy rice variety was stored under humid-sub-humid (HSH), and dry (DRY) conditions for 12 months. Over 12 months, rice stored under DRY conditions experienced greater environmental fluctuations than rice stored under HSH conditions. Grain water absorption capacity (WAC) increased during storage under DRY conditions, rising from 3.3 ± 0.3 to 3.8 ± 0.3 g/g DM between 0 and 12 months. Flour amylose content and soluble solids remained relatively stable from month 0 to 6 in all conditions, and further under HSH conditions. The observed changes led to improved grain cooking performance after 6 months of storage under DRY conditions. After 12 months, a decrease in rice flour WAC and a peak in viscosity were observed, while mean particle size increased from 42 ± 1 to 67 ± 3 µm under HSH conditions and from 31 ± 3 to 83 ± 3 µm under DRY conditions. Storage time may reduce the breadmaking capacity of rice flour. Overall, environmental fluctuations under DRY conditions strongly affected rice grain and flour properties.</div
Zero-inflated binary Tree Pólya splitting regression for multivariate count data
No full textSpecies distribution models (SDMs) are widely used to assess the effects of environmental factors on speciesdistributions. However, classical SDMs ignore inter-species dependencies. Multivariate SDMs (MSDMs), especially those basedon latent Gaussian fields such as the multivariate Poisson log-normal (MPLN), address this limitation but face challengesrelated to computation, dimensionality, and interpretability. Pólya-splitting (PS) distributions offer an alternative, combininga model for total abundance with a multivariate allocation structure, and have natural interpretations from ecological processmodels. Yet, they lack flexibility in modeling correlation structures. Tree Pólya-splitting (TPS) distributions overcome thisby introducing hierarchical structure such as a phylogenetic tree. In this paper, we extend TPS to account for zero-inflation,leading to the zero-inflated tree Pólya-splitting (Z-TPS) family. We detail its statistical properties, show how standard softwareenables efficient inference, and illustrate its ecological relevance using tree abundance data from over 180 genera across theCongo Basin tropical rainfores
The North Balearic Front as an ecological boundary: zooplankton fine-scale distribution patterns in late spring
No full textInternational audienceObservations, models and theory have suggested that ocean fronts are ecological hotspots, generally associated with higher diversity and biomass across many trophic levels. Nutrient injections are often associated with higher chlorophyll concentrations at fronts, but the response of the zooplankton community is still insufficiently understood. The present study investigates mesozooplankton stocks and composition during late spring, northeast of Menorca, along two north-south transects that crossed the North Balearic Front separating central waters of the Northwestern Mediterranean Sea gyre from peripheral waters originating from the Algerian basin. During the BioSWOT-Med campaign, vertical triple-net tows with 200 and 500 µm meshes were carried out at three depths (100, 200, and 400 m), and the samples were processed with ZooScan to classify organisms into eight taxonomic groups. Zooplankton distributions were analyzed for the surface layer (0–100 m), a mid-depth layer (100–200 m), and a deeper layer (200–400 m). The results did not show a significant increase in biomass in the front in any layers. The NBF appears to act as a boundary between communities rather than a pronounced area of active or passive zooplankton accumulation. Analyses of stratified vertical distributions of zooplankton highlighted distinct taxonomic compositions in the three layers, and a progressive homogenization of community structure with depth, reflecting a weaker impact of hydrological processes on deeper communities. The clearest impact of the front was within the upper 100 m, where the mesozooplanktonic taxonomic composition differed between the front and adjacent water masses, with a decrease in all taxonomic groups except Cnidaria, which increased dramatically. In the two deeper layers, the front also influenced community composition, although to a lesser extent, with marked increases in Foraminifera and Cnidaria. Moreover, the northern water mass and the front were dominated by large copepods, while the southern water mass exhibited higher zooplankton diversity and smaller-sized copepods. The results of this study highlight the complexity of processes shaping planktonic communities over time and space in the NBF zone and its adjacent waters. These processes include zooplankton stock reduction in the transitional post-bloom period, marked effect of diel variation linked to vertical migrations, and potentially the impact of storm-related mixing in the surface layer that can disrupt established ecological patterns
INTERMEDIATE RESISTANCE AND CAPACITANCE STATES IN Ge-RICH GeSbTe PHASE CHANGE MEMORY
No full textInternational audienceWe investigate intermediate states of Ge-rich GeSbTe phase-change memory cells by electrical impedance spectroscopy after partial SET and RESET programming. The impedance response is well described by a series resistor and a parallel RC circuit, allowing extraction of state-dependent resistance and capacitance values. A resistance contrast of and a capacitance reduction of are observed between RESET and SET states. While resistance can be continuously tuned, capacitance major variation remains confined near the SET state, with crystalline-dominated cells exhibiting the highest values. Technology Computer-Aided Design simulations confirm the equivalent circuit and reveal that conduction mainly occurs along the amorphouscrystalline interface. Cells with embedded Ge or Sb grains display the largest capacitances, as these inclusions provide extra conduction pathways and localized charge storage sites that jointly influence the device's resistance and capacitance. Overall, this work demonstrates that the electrical properties of inhomogeneous multiphase PCMs are governed by the complex network of nanoscale heterostructures present in their active regions. It also demonstrates that impedance spectroscopy is a suitable, non-destructive technique for characterizing PCM devices.</div