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International audience; The p-type Ge-doped (0, 1, 4 and 7 at.%) Mg

Membraneless organelles are phase-separated droplets that are dynamically assembled and dissolved in response to biochemical reactions in cells. Complex coacervate droplets produced by associative liquid–liquid phase separation offer a promising approach to mimic such dynamic compartmentalization. Here, we present a model for membraneless organelles based on enzyme/polyelectrolyte complex coacervates able to induce their own condensation and dissolution. We show that glucose oxidase forms coacervate droplets with a cationic polysaccharide on a narrow pH range, so that enzyme-driven monotonic pH changes regulate the emergence, growth, decay and dissolution of the droplets depending on the substrate concentration. Significantly, we demonstrate that time-programmed coacervate assembly and dissolution can be achieved in a single-enzyme system. We further exploit this self-driven enzyme phase separation to produce multiphase droplets via dynamic polyion self-sorting in the presence of a secondary coacervate phase. Taken together, our results open perspectives for the realization of programmable synthetic membraneless organelles based on self-regulated enzyme/polyelectrolyte complex coacervation., Self-programmed enzyme phase separation is exploited to assemble dynamic multiphase coacervate droplets via spontaneous polyion self-sorting under non-equilibrium conditions.

Background Biannual rituximab infusions over 18 months effectively maintain remission after a "standard" remission induction regimen for patients with antineutrophil cytoplasmic antibody-associated vasculitis (AAV). Objective To evaluate the efficacy of prolonged rituximab therapy in preventing AAV relapses in patients with granulomatosis with polyangiitis (GPA) or microscopic polyangiitis (MPA) who have achieved complete remission after completing an 18-month maintenance regimen. Design Randomized controlled trial. (ClinicalTrials.gov: NCT02433522). Setting 39 clinical centers in France. Patients 68 patients with GPA and 29 with MPA who achieved complete remission after the first phase of maintenance therapy. Intervention Rituximab or placebo infusion every 6 months for 18 months (4 infusions). Measurements The primary end point was relapse-free survival at month 28. Relapse was defined as new or reappearing symptoms or worsening disease, with a Birmingham Vasculitis Activity Score greater than 0. Results From March 2015 to April 2016, 97 patients (mean age, 63.9 years; 35% women) were randomly assigned, 50 to the rituximab and 47 to the placebo group. Relapse-free survival estimates at month 28 were 96% (95% CI, 91% to 100%) and 74% (CI, 63% to 88%) in the rituximab and placebo groups, respectively, an absolute difference of 22% (CI, 9% to 36%) with a hazard ratio of 7.5 (CI, 1.67 to 33.7) (P = 0.008). Major relapse-free survival estimates at month 28 were 100% (CI, 93% to 100%) versus 87% (CI, 78% to 97%) (P = 0.009), respectively. At least 1 serious adverse event developed in 12 patients (24%) in the rituximab group (with 9 infectious serious adverse events occurring among 6 patients [12%]) versus 14 patients (30%) in the placebo group (with 6 infectious serious adverse events developing among 4 patients [9%]). No deaths occurred in either group. Limitation Potential selection bias based on previous rituximab response and tolerance. Conclusion Extended therapy with biannual rituximab infusions over 18 months was associated with a lower incidence of AAV relapse compared with standard maintenance therapy. Primary funding source French Ministry of Health and Hoffmann-La Roche.

International audience; Global warming is expected to increase droughts and heatwaves, and consequently fire danger in southern Europe in the forthcoming decades. However, an assessment of the uncertainties associated with this general trend at regional scales, relevant to decision-making, is still missing. This study aims at assessing potential climate change impacts on fire danger over France through the projection of the widely used Fire Weather Index (FWI) and at quantifying the different sources of climate-driven uncertainty associated with these projections. We used daily climate experiments covering the 1995-2098 period under two scenarios (RCP4.5 and RCP8.5) provided by the EURO-CORDEX initiative. Our results show an overall increase in FWI throughout the century, with the largest absolute increases in the Mediterranean area. Model uncertainty was very high in western France, previously identified as a potential fire-prone region under future climate. In contrast, large increases in FWI in the Mediterranean area showed low uncertainty across models. Besides, analyzing the natural variability of FWI revealed that extreme years under present-day climate could become much more frequent by the end of the century. The FWI is projected to emerge from the background of natural variability by mid-twenty-first century with a summer elevated fire danger three times more likely when summer temperature anomaly exceeds + 2 degrees C.

International audience; The spatial forest structure that drives the functioning of these ecosystems and their response to global change is closely linked to edaphic conditions. However, the latter properties are particularly difficult to characterize in forest areas developed on karst, where soil is highly rocky and heterogeneous. In this work, we investigated whether geophysics, and more specifically electromagnetic induction (EMI), can provide a better understanding of forest structure. We use EMI (EM31, Geonics Limited, Ontario, Canada) to study the spatial variability of ground properties in two different Mediterranean forests. A naturally post-fire regenerated forest composed of Aleppo pines and Holm oaks and a monospecific plantation of Altlas cedar. To better interpret EMI results, we used electrical resistivity tomography (ERT), soil depth surveys, and field observations. Vegetation was also characterized using hemispherical photographs that allowed to calculate plant area index (PAI). Our results show that the variability of ground properties contribute to explaining the variability in the vegetation cover development (plant area index). Vegetation density is higher in areas where the soil is deeper. We showed a significant correlation between edaphic conditions and tree development in the naturally regenerated forest, but this relationship is clearly weaker in the cedar plantation. We hypothesized that regular planting after subsoiling, as well as sylvicultural practices (thinning and pruning) influenced the expected relationship between vegetation structure and soil conditions measured by EMI. This work opens up new research avenues to better understand the interplay between soil and subsoil variability and forest response to climate change.

International audience; Mediterranean forests face an intensification of droughts caused by ongoing climate change. To improve our understanding of tree and forest responses to increasing drought, we explored over nine years, the effects of a 30% rainfall exclusion experiment on the water potential, sap velocity and primary and secondary growth of two co-occurring species (Quercus ilex and Pinus halepensis) in a French Mediterranean forest. In addition, native embolism was measured after six and nine years of exclusion onset. Water potentials decreased earlier during summer drought for both species in the rainfall exclusion plot, and to a higher extent during the drought peak for Q. ilex, involving earlier stomatal closure and reduced sap velocity. Sap velocity reduction persisted throughout the years in the exclusion plot. Outside summer the water potential difference between predawn and midday was similar between treatment which indicate that reduced water transport efficiency may be linked to decrease hydraulic conductance. Such differences were neither related to differences in xylem embolism, that remained similar between treatments, nor to change in secondary growth. In contrast primary growth measurements indicate that P. halepensis trees, and Q. ilex to a lesser extent, experienced reduction in total leaf areas in response to the rainfall exclusion. Globally, our results suggest that increase drought lead, for both species, to a decrease in sap velocity not mediated by increase embolism but rather by a reduction in primary growth. So far little conclusion can be drawn regarding the competitive advantage of one species over the other in the context of increasing drought related to climate change.

International audience; As part of the 2015 Paris climate agreement and under its Green Deal, the EU proposes to strongly rely on forests for offsetting its carbon footprint. However, planting trees should be avoided in wildfire prone and drought prone habitats, which are expanding significantly as climate warms across Europe. In favorable habitats, tree planting remains a controversial solution and the risk of using inappropriate material is high in the absence of long-term planning, unfortunately typical of the forest seed and nursery sector. The EU forest tree planting strategy should pay close attention to local land-use issues, to within- and among-species genetic diversity and should adopt relevant, pluri-annual funding schemes and planting contracts rather than letting market opportunities govern the future of forest tree plantations.

International audience; Aquifer recharge may depend mainly on the difference between precipitation and evapotranspiration. Hydrological models used to estimate groundwater reserves use evapotranspiration models that are mainly determined by climate demand. In particular, mechanisms of plant transpiration are neglected, although transpiration constitutes 70% of evapotranspiration. This is problematic when considering karst watershed, which are poorly documented at the interface between soil and atmosphere where vegetation and soil properties control water flows. To fill this gap, we propose an evapotranspiration model that integrates the processes of plant transpiration and soil evaporation. The dynamics of vegetation is evaluated using the Enhanced Vegetation Indexes from the Terra and Aqua Moderate Resolution Imaging Spectroradiometers. The soil evaporation calculation account for the impact of coarse elements at soil surface. The “Simple Crop coefficient for Evapotranspiration” (SimpKcET) model is tested at flux tower sites over forest of Font-Blanche, Puechabon and the agricultural area of Avignon. The simulated daily evapotranspirations are very close to the observations (RMSE ~0.5 mm.d-1), while the model is simple compared to other models proposed in the literature. The SimpKcET is implemented in a karst hydrological model to evaluate the impact of evapotranspiration estimation on the aquifer flow rate simulation. This approach is applied to the vast watershed of Fontaine de Vaucluse. In comparison to the water bucket model that is frequently used in karst models, SimpKcET provide ET simulations that are more in line with ET processes. A cross wavelet analysis highlighted the improvement of the simulated recharge and observed flow rate relationship brought by the consideration of evaporation and transpiration processes. The use of remote sensing data related to plant activity makes it possible to propose a parsimonious model that can be applied to all types of vegetation (agricultural, natural, mixed forest) and that can be transferred to other karst models.

Data are available in PROMÉTHÉE2: Forest fires database for Mediterranean area in France, and can be extracted at https://www.promethee.com/en/incendies using the following selection criteria: fire type, Forêt; date range, 1 January 1995 to 31 December 2018.; International audience; Modeling wildfire activity is crucial for informing science-based risk management and understanding the spatiotemporal dynamics of fire-prone ecosystems worldwide. Models help disentangle the relative influences of different factors, understand wildfire predictability, and provide insights into specific events. Here, we develop Firelihood, a two-component, Bayesian, hierarchically structured, probabilistic model of daily fire activity, which is modeled as the outcome of a marked point process: individual fires are the points (occurrence component), and fire sizes are the marks (size component). The space-time Poisson model for occurrence is adjusted to gridded fire counts using the integrated nested Laplace approximation (INLA) combined with the stochastic partial differential equation (SPDE) approach. The size model is based on piecewise-estimated Pareto and generalized Pareto distributions, adjusted with INLA. The Fire Weather Index (FWI) and forest area are the main explanatory variables. Temporal and spatial residuals are included to improve the consistency of the relationship between weather and fire occurrence. The posterior distribution of the Bayesian model provided 1,000 replications of fire activity that were compared with observations at various temporal and spatial scales in Mediterranean France. The number of fires larger than 1 ha across the region was coarsely reproduced at the daily scale, and was more accurately predicted on a weekly basis or longer. The regional weekly total number of larger fires (10-100 ha) was predicted as well, but the accuracy degraded with size, as the model uncertainty increased with event rareness. Local predictions of fire numbers or burned areas also required a longer aggregation period to maintain model accuracy. The estimation of fires larger than 1 ha was also consistent with observations during the extreme fire season of the 2003 unprecedented heat wave, but the model systematically underrepresented large fires and burned areas, which suggests that the FWI does not consistently rate the actual danger of large fire occurrence during heat waves. Firelihood enabled a novel analysis of the stochasticity underlying fire hazard, and offers a variety of applications, including fire hazard predictions for management and projections in the context of climate change.

Boiling water reactors are simulated using nodal diffusion core simulators which rely upon homogenized and condensed cross sections from a lattice physics code. In the lattice calculation, the void distribution is typically assumed to be uniform in the radial direction. To remove this assumption, a thermal hydraulic code can be coupled with a lattice physics code to include a radial void distribution in the cross sections. To minimize the additional computational costs, a surrogate model can be generated for the thermal hydraulic code. In this research, a surrogate model is generated for the thermal hydraulic code F-COBRA-TF using sparse grid interpolation. The surrogate model is tested on how well it can reproduce the F-COBRA-TF void distribution for various conditions on the ATRIUM 10 assembly. The surrogate model is found to be effective at reproducing the F-COBRA-TF void distribution and reducing the computational costs from the order of minutes to about a second. A coupling is created between the surrogate model and the lattice physics code APOLLO2-A. Including the void distribution in the lattice physics calculation is found to have a large effect on the gadolinium worth.

Light polarization control is a key factor in modern photonics. Recent advances in surface plasmon manipulation have introduced the prospect of more compact and more efficient devices for this purpose. However, the current plasmonic-based polarization optics remain much larger than the wavelength of light, which limits the design degrees of freedom. Here, we present a plasmonic traveling-wave nanoantenna using a gold-coated helical carbon nanowire end-fired with a dipolar aperture nanoantenna. Our nonresonant helical nanoantenna enables tunable polarization control by swirling surface plasmons on the subwavelength scale and taking advantage of the optical spin–orbit interaction. Four closely packed helical traveling-wave nanoantennas (HTNs) are demonstrated to locally convert an incoming light beam into four beams of tunable polarizations and intensities, with the ability to impart different polarization states to the output beams in a controllable way. Moreover, by near-field coupling four HTNs of opposite handedness, we demonstrate a subwavelength waveplate-like structure providing a degree of freedom in polarization control that is unachievable with ordinary polarization optics and current metamaterials., Nano-optics: polarization control Gold-coated carbon nanowire spirals offer an ultra-compact means of controlling the polarization state of light. The helical structures, designed and fabricated by a French-Chinese collaboration from the FEMTO-ST Institute in France and Jinan University in China, use surface plasmons and optical spin-orbit interactions to convert an incoming linearly-polarized light beam into a circularly polarized output. Incident light is coupled into a plasmon mode of the helical nanowires via a rectangular aperture nanoantenna that perforates a thin gold layer at the base of the helix. The small size of the nanowires means that several can be packed together and the team demonstrate an array of 4 coupled structures, two with a left-handed helix and two with a right-handed helix, allowing tunable polarization control. Potential applications include use in displays, data storage, microscopy and sensing.

International audience; The prebiotic organization of chemicals into compartmentalized ensembles is an essential step to understand the transition from inert molecules to living matter. Compartmentalization is indeed a central property of living systems. Fatty acids represent the simplest prebiotic amphiphiles capable of self-assembling into membrane-bound vesicles, and have therefore emerged as valuable molecules to create models of protocellular compartments. Here, the main experimental findings that support this idea are reviewed, together with approaches to increase the stability of fatty acid vesicles in adverse pH, salt or temperature conditions. Recent studies on the self-assembly of fatty acids into membrane-free coacervate micro-droplets are then discussed, providing a promising new paradigm for prebiotic compartmentalization. We last argue that the unique possibility of cycling between fatty acid vesicles and coacervates paves the way to an exciting new hypothesis for the emergence of the first living protocells.

Oral healthcare has an environmental impact that is specific to the profession and is currently unsustainable. This impact results in unwanted and difficult-to-manage waste, carbon emissions and other environmental impacts that contribute to climate change. Contributions to this pollution come from the supply chain that provides the required materials and sundries, patient and staff commuting/travelling, direct patient care, the use and end-of-life management of restorative materials and single-use plastics (SUPs) such as personal protective equipment (PPE). This article explores these various contributors to pollution arising from oral healthcare. CPD/Clinical Relevance: The provision of oral healthcare has an environmental impact that requires consideration and action in order to become sustainable.

Key message A new process-based model,SurEau, is described. It predicts the risk of xylem hydraulic failure under drought. Context The increase in drought intensity due to climate change will accentuate the risk of tree mortality. But very few process-based models are currently able to predict this mortality risk. Aims We describe the operating principle of a new mechanistic model SurEau that computes the water balance, water relations, and hydraulics of a plant under extreme drought. Methods SurEau is based on the formalization of key physiological processes of plant response to water stress. The hydraulic and hydric functioning of the plant is at the core of this model, which focuses on both water flows (i.e., hydraulic) and water pools (i.e., hydric) using variable hydraulic conductances. The model considers the elementary flow of water from the soil to the atmosphere through different plant organs that are described by their symplasmic and apoplasmic compartments. For each organ, the symplasm is described by a pressure-volume curve and the apoplasm by its vulnerability curve to cavitation. The model is evaluated on mature oak trees exposed to water stress. Results On the tested oak trees, the model captures well the observed soil water balance, water relations, and level of embolism. A sensitivity analysis reveals that the level of embolism is strongly determined by air VPD and key physiological traits such as cuticular transpiration, resistance to cavitation, and leaf area. Conclusion The process-based SurEau model offers new opportunities to evaluate how different species or genotypes will respond to future climatic conditions.

International audience; Adaptation to drought involves complex interactions of traits that vary within and among species. To date, few data are available to quantify within-species variation in functional traits and they are rarely integrated into mechanistic models to improve predictions of species response to climate change.We quantified intraspecific variation in functional traits of two Hakea species growing along an aridity gradient in southeastern Australia. Measured traits were later used to parameterise the model SurEau to simulate a transplantation experiment to identify the limits of drought tolerance.Embolism resistance varied between species but not across populations. Instead, populations adjusted to drier conditions via contrasting sets of trait trade-offs that facilitated homeostasis of plant water status. The species from relatively mesic climate, Hakea dactyloides, relied on tight stomatal control whereas the species from xeric climate, Hakea leucoptera dramatically increased Huber value and leaf mass per area, while leaf area index (LAI) and epidermal conductance (g(min)) decreased. With trait variability, SurEau predicts the plasticity of LAI and g(min) buffers the impact of increasing aridity on population persistence.Knowledge of within-species variability in multiple drought tolerance traits will be crucial to accurately predict species distributional limits.

Poultry and swine farming are large contributors to environmental impacts, such as climate change, eutrophication, acidification, and air and water pollution. Feed production and manure management are identified as the main sources of these impacts. Reducing dietary crude protein levels is a nutritional strategy recognized to both decrease the use of high-impact feed ingredients and alter manure composition, reducing emissions of harmful components. For a successful implementation of this technique, feed-grade amino acid supplementation is crucial to maintaining animal performance. Reducing crude protein lowers nitrogen excretion, especially excess nitrogen excreted in urea or uric acid form, improving nitrogen efficiency. At the feed-gate, low–crude protein diets can reduce the carbon footprint of feed production through changes in raw material inclusion. The magnitude of this reduction mainly depends on the climate change impact of soybean meal and its land-use change on the feed-grade amino acids used. Reducing dietary crude protein also lowers the environmental impact of manure management in housing, storage, and at spreading: nitrogen emissions from manure (ammonia, nitrates, nitrous oxide) are reduced through reduction of nitrogen excretion. Moreover, synergetic effects exist with nitrogen form, water excretion, and manure pH, further reducing emissions. Volatilization of nitrogen is more reduced in poultry than in pigs, but emissions are more studied and better understood for pig slurry than poultry litter. Ammonia emissions are also more documented than other N-compounds. Low–crude protein diets supplemented with amino acids is a strategy reducing environmental impact at different stages of animal production, making life cycle assessment the best-suited tool to quantify reduction of environmental impacts. Recent studies report an efficient reduction of environmental impacts with low–crude protein diets. However, more standardization of limits and methods used is necessary to compare results. This review summarizes the current knowledge on mitigation of environmental impacts with low–crude protein diets supplemented with amino acids in poultry and swine, its quantification, and the biological mechanisms involved. A comparison between pigs and poultry is also included. It provides concrete information based on quantified research for decision making for the livestock industry and policy makers.

International audience

Many banned persistent organic pollutants (POPs) remain for decades in the aquatic environment and can have harmful effects on long-lived predators because of their high bioaccumulation and biomagnification potentials. We investigated the occurrence and levels of 18 polychlorinated biphenyls (PCBs) and 16 organochlorine pesticides in European pond turtles (n = 174) from April to July 2018 in the Camargue wetland, France. Although the Camargue was highly contaminated in previous decades, plasma occurrence and levels of POPs were very low: we were able to quantify only 3 of the 34 compounds we analyzed in >10% of the turtles. The burdens from POPs did not differ between males and females and were uncorrelated with sampling date and body mass. We observed differences in POP burdens between turtles from the 2 sampling sites. One possible explanation is that the sampling sites were in different agricultural hydraulic systems: plasma occurrence and levels were higher for PCB-52 and hexachlorobenzene in turtles captured in drainage channels and for PCB-153 at the site that receives irrigation. Finally, the occurrence and levels of PCB-153 in turtles increased with age, likely because of bioaccumulation and much higher exposure 20 to 30 yr ago than now. Environ Toxicol Chem 2021;40:2261-2268. © 2021 SETAC.

International audience; Climate change impacts forest functioning and dynamics, and large uncertainties remain regarding the interactions between species composition, demographic processes and environmental drivers. There are few robust tools available to link these processes, which precludes accurate projections and recommendations for long-term forest management. Forest gap models present a balance between complexity and generality and are widely used in predictive forest ecology. However, their relevance to tackle questions about the links between species composition, climate and forest functioning is unclear. In this regard, demonstrating the ability of gap models to predict the growth of forest stands at the annual parameterization scale resolution—representing a sensitive and integrated signal of tree functioning and mortality risk—appears as a fundamental step. In this study, we aimed at assessing the ability of a gap model to accurately predict forest growth in the short term and potential community composition in the long term, across a wide range of species and environmental conditions. To do so, we present the gap model ForCEEPS, calibrated using an original parameterization procedure for the main tree species in France. ForCEEPS was shown to satisfactorily predict forest annual growth (averaged over a few years) at the plot level from mountain to Mediterranean climates, regardless of the species. Such an accuracy was not gained at the cost of losing precision for long-term predictions, as the model showed a strong ability to predict potential community compositions. The mechanistic relevance of ForCEEPS parameterization was explored by showing the congruence between the values of key model parameter and species functional traits. We further showed that accounting for the spatial configuration of crowns within forest stands, the effects of climatic constraints and the variability of shade tolerances in the species community are all crucial to better predict short-term productivity with gap models. Synthesis. The dual ability of predicting short-term functioning and long-term community composition, as well as the balance between generality and realism (i.e. predicting accuracy) of the new generation of gap models may open great perspectives for the exploration of the biodiversity–ecosystem functioning relationships, species coexistence mechanisms and the impacts of climate change on forest ecosystems. A free Plain Language Summary can be found within the Supporting Information of this article.

International audience

International audience; Delafossite CuFeO2 films have been synthesized by reactive magnetron sputtering at different substrate temperatures from 380 up to 550 °C. The films adopt the rhombohedral structure from 380 to 550 °C. At the highest temperature, the delafossite phase partially dissociates in FCC Cu and Fe3O4 magnetite phases. In addition to the average crystallite size increase, a change of the preferential orientation in the out-of-plane direction from the [012] to [006] directions occurs between 460 and 510 °C. Modelling of the optical properties shows the presence of 2 interband transitions in the visible range. The 1st main transition at 1.5 eV is ascribed to the absorption component parallel to the c-axis whereas the 2nd transition (2.10 – 2.26 eV) is related to the absorption component in the (a, b) plane. Both evolutions with temperature of the refractive index (~ 2.5) and absorption coefficient (~ 10-3 cm-1) in the infrared suggest the formation of secondary phases. The electronic conductivity, dominated by positive charge carrier, varied from 0.01 to 10 S m-1 according to the preferential orientation and to the presence of secondary phases. A very small amount of a short-range ferromagnetic component (magnetization ~ 10 kA m-1 at 1.5 T) is clearly observed at room temperature thanks to magnetometry confirming the formation of secondary phases undetected by X-ray diffraction. In addition to depend on the film orientation, the presence of secondary phases in weak proportion alters the optical and electrical behaviours such as the transmittance in the visible range..

International audience; Plant transpiration is a major component of water fluxes in the critical zone, which needs to be better characterized to improve our ability to understand and model the hydrological cycle. In water-limited ecosystems such as those encountered on karst environments, climate-induced changes in transpiration are expected to be strongly influenced by the ability of the vegetation cover to resist or adapt to drought. However, because of the high heterogeneity of karst environments, the amount of water available for trees can change within a stand, which may lead to significant differences in drought vulnerability resistance between trees of the same species. So far it is not known if soil and subsoil environment influence the magnitude of deep water extraction, at the intra-specific scale. Here, we investigate the variability in deep water extraction for six individual Quercus ilex trees growing on a karst substrate in a Mediterranean forest. We combined three approaches: (i) electrical resistivity tomography to determine the variability of soil/subsoil characteristics, (ii) isotope tracing to determine the origin of water transpired by plants, and (iii) predawn and midday leaf water potential (Ψ) to assess the trees’ water stress and transpiration regulation. Along the summer season, deep water extraction increased with drought intensity. Deep water use varies between individuals and according to drought intensity. At moderate water stress levels, we found no significant relationship between the origin of xylem water and soil/subsoil characteristics or individual stress level. However, at the peak of the drought (average predawn Ψ < −2 MPa), individuals that had the least total available water in soil/subsoil (0–2 m) relied more on deep water and were also subject to less water stress. These results suggest that trees with less favorable soil/subsoil conditions (i.e. low water retention capacity) in the near surface (0–2 m) adapt their root systems to exploit deep water reserves more intensively so as to enhance their drought tolerance, while trees with more favorable surface conditions exhibit greater water stress and may be more vulnerable to extreme droughts because of a lower root development in deeper horizons.

Peer-reviewed by PCI Forest Wood Sciences https://forestwoodsci.peercommunityin.org/Peer-reviewed by PCI Forest Wood Sciences https://forestwoodsci.peercommunityin.org/; In temperate, boreal and alpine areas, the edges of plant distribution are strongly affected by abiotic constraints. For example, heat waves and drought are major constraints at low latitude and elevation while cold and frost are key factors at high latitude and elevation. Over the next few decades, climate variability is expected to increase, enhancing the probability of extreme events and thus the potential stress imposed by abiotic constraints. Moreover, the likelihood of co-occurring and successive constraints, such as drought and frost, could increase in parallel. It is likely that initial exposure to a first constraint would affect the vulnerability to a subsequent one. Three integrative physiological processes, namely water status, carbon status and the timing of phenological stages, are crucial to understanding how trees will respond to these stress factors. Although these processes have largely been studied alone, in response to a single constraint, their interaction has rarely been investigated. In this paper, we have examined how water and carbon status interact with the growth cycle and affect both the vulnerability and the exposure to climatic constraints via two different focuses: (i) How would the interaction of frost and drought constraints modulate the vulnerability to a subsequent constraint? (ii) How vulnerability to a given constraint and phenology interact? In the light of numerous papers, we suggest that the interaction between frost and drought constraints should in the short-term influence water status and, in the longer term, the carbon status, both consequently affecting further vulnerability, potentially leading to a decline. This vulnerability can also be modulated by a shift in the annual phenological cycle induced by a previous constraint. Furthermore, we have identified significant gaps of knowledge in the ecophysiological tree response to interacting stresses based on three major points: (i) the spatio-temporal variation in carbohydrate composition, fluxes and allocation in relation to environmental drivers, (ii) the spatio-temporal variation in water content, water and osmotic potentials, (iii) the modulation of phenological processes in response to stress. This framework can help to improve the current process based models and to identify interactions that needs to be better described in order to obtain a more quantitative and dynamic view of drought and frost vulnerabilities integrating the life history of the individual plant.; Dans les zones tempérées, boréales et alpines, les limites de distribution des plantes sont fortement affectées par les contraintes abiotiques. Les vagues de chaleur et la sécheresse sont des contraintes majeures à basse latitude et altitude, tandis que le froid et le gel sont des facteurs clés à haute latitude et altitude. Au cours des prochaines décennies, la variabilité du climat devrait s'accroître, augmentant la probabilité d'événements extrêmes et donc le stress potentiel imposé par les contraintes abiotiques. En outre, la probabilité de contraintes concomitantes et successives, telles que la sécheresse et le gel, pourrait augmenter en parallèle. Il est probable que l'exposition initiale à une première contrainte affecterait la vulnérabilité à une contrainte ultérieure. Trois processus physiologiques intégratifs, à savoir le statut hydrique, le statut carboné et le cycle annuel de croissance sont essentiels pour comprendre comment les arbres réagiront à ces facteurs de stress. Bien que ces processus aient été largement étudiés isolément, en réponse à une seule contrainte, leur interaction a rarement été étudiée. Dans ce document, nous avons examiné comment le statut hydrique et carboné interagissent avec le cycle annuel de croissance et affectent à la fois la vulnérabilité et l'exposition aux contraintes climatiques. Deux axes ont été explorés : (i) Comment l'interaction des contraintes de gel et de sécheresse module-t-elle la vulnérabilité à une contrainte ultérieure ? (ii) Comment la vulnérabilité à une contrainte donnée et la phénologie interagissent-elles ? À la lumière de nombreux articles, nous suggérons que l'interaction entre les contraintes de gel et de sécheresse devrait, à court terme, influencer le statu hydrique et, à plus long terme, le statu carboné, les deux affectant par conséquent la vulnérabilité, pouvant mener vers la mortalité de la plante. Cette vulnérabilité peut également être modulée par des variations des stades phénologiques induit par une contrainte antérieure. En outre, nous avons identifié des lacunes de connaissance sur la réponse écophysiologiques des arbres à l’interaction de stress à trois principaux niveaux : (i) variation spatio-temporelle de la composition, des flux et de l'allocation des glucides en relation avec les facteurs environnementaux, (ii) variation spatio-temporelle de la teneur en eau et des potentiels hydrique et osmotiques, (iii) la modulation des processus phénologiques en réponse à un stress. Ce cadre peut contribuer à améliorer les modèles actuels basés sur les processus et à identifier les interactions qui doivent être mieux décrites afin d'obtenir une vision plus quantitative et dynamique des vulnérabilités à la sécheresse et au gel, en intégrant l’histoire de vie de la plante.

Climate change impacts forest functioning and dynamics, and large uncertainties remain regarding the interactions between species composition, demographic processes, and environmental drivers. There are few robust tools available to link these processes, which precludes accurate projections and recommendations for long-term forest management. Forest gap-models present a balance between complexity and generality and are widely used in predictive forest ecology. However, their relevance to tackle questions about the links between species composition, climate and forest functioning is unclear. In this regard, demonstrating the ability of gap-models to predict the growth of forest stands at the annual time scale – representing a sensitive and integrated signal of tree functioning and mortality risk - appears as a fundamental step.In this study, we aimed at assessing the ability of a gap-model to accurately predict forest growth in the short-term and potential community composition in the long-term, across a wide range of species and environmental conditions. To do so, we present the gap-model ForCEEPS, calibrated using an original parameterization procedure for the main tree species in France. ForCEEPS was shown to satisfactorily predict forest annual growth (averaged over a few years) at the plot level from mountain to Mediterranean climates, regardless the species. Such an accuracy was not gained at the cost of losing precision for long-term predictions, as the model showed a strong ability to predict potential community composition along a gradient of sites with contrasted conditions. The mechanistic relevance of ForCEEPS parameterization was explored by showing the congruence between the values of key model parameter and species functional traits. We further showed that accounting for the spatial configuration of crowns within forest stands, the effects of climatic constraints and the variability of shade tolerances in the species community are all crucial to better predict short-term productivity with gap-models.The dual ability of predicting short-term functioning and long-term community composition, as well as the balance between generality and realism (i.e., predicting accuracy) of the new generation of gap-models may open great perspectives for the exploration of the biodiversity-ecosystem functioning relationships, species coexistence mechanisms, and the impacts of climate change on forest ecosystems.

Wildfire is the main disturbance in forested ecosystems of southern Europe and is due to complex interactions between climate-weather, fuels and people. Warmer and drier conditions projected in this region are expected to profoundly affect wildfires, which will impact ecosystems and humans. We review the scientific literature addressing the assessment of climate change impacts on wildfires in southern Europe, with a twofold objective: (i) report the trends in wildfire danger and activity projected under warming climate in southern Europe and (ii) discuss the limitations of wildfire projections under the specific biogeographical context of southern Europe.We identified 22 projection studies that examined future wildfire danger or wildfire activity at local, regional or continental scale. Under the scenario with the highest greenhouse gas emissions, we found that projections studies estimate an increase in future fire danger and burnt areas varying, on average, from 2 to 4 % and from 15 to 25 % per decade, respectively. Fire-prone area expansion to the north and to Mediterranean mountains is a concern, while climate-induced burnt area increase might be limited by fuel availability in the most arid areas. While all studies agreed on the direction of changes, further comparisons on the magnitude of increase remained challenging because of heterogeneous methodological choices between projections studies (climate models, projection period, spatial scale and fire metrics). We then described three main sources of uncertainty that may affect the reliability of wildfire projections: climate projections, climate-fire models, and the influences of fuel load/structure and human related factors on the climate-fire relationships. We finally suggest research directions to address some of these issues for the purpose of refining fire danger and fire activity projections in southern Europe.

Metallic platinum&ndash, titanium coatings were deposited by co-sputtering of two metallic Pt and Ti targets in pure argon atmosphere. The titanium concentrations varied from 0 to 47 atomic percent and were adjusted as a function of the current applied to the titanium target. The structural and chemical features of these films were assessed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). All as-deposited coatings exhibit a perfect covering of the alumina pellets&rsquo, substrate surface. The coatings containing more than 4 at.% Ti are amorphous, whereas the others crystallize in the face-centered cubic (fcc) structure of platinum. After an annealing treatment under air for 2 h, all of the coatings adopt the fcc structure with a crystallization temperature depending on the titanium content. For titanium concentrations higher than 32 at.%, the TiO2 phase appears during the annealing treatment. For the smaller film thickness of Pt&ndash, Ti alloys (15 nm), the Ostwald ripening mechanism is observed by SEM increasing the annealing temperature regardless of the content of Ti. The film resistivity measured at room temperature is lower than 7 10&minus, 4 &Omega, &middot, cm and increases with the temperature to achieve an insulating behavior (in air and reducing atmosphere Ar-H2 (90-10) at 1123 K the resistivity is &rho, 10+36 &Omega, cm). When the thickness of intermetallic Pt3Ti layer is higher than 50 nm, the coating is continuous and the resistivity is below 5 10&minus, cm in air and in reducing atmosphere (Ar with 10% of H2) up to 1273 K.

International audience; Poly(3,4-ethylenedioxythiophene)–polystyrene sulfonate (PEDOT:PSS) conjugated polymer blend and a cationic poly(3-hexylthiophene) (P3HT)-based conjugated polyelectrolyte incorporating imidazolium ionic side groups were first adsorbed as monolayer on inorganic colloidal particles. At the plateau of adsorption isotherm, adsorbed amount of PEDOT:PSS on alumina particles appears lower than the adsorbed amount of P3HT on silica particles. Both polyelectrolytes strongly modify the surface charge of particles as reveals by zeta potential variation. Functionalized particles were then assembled using Layer-by-Layer method in order to prepare (PDDA/Al2O3-PEDOT:PSS)n and (SiO2-P3HT/PEDOT:PSS)n conductive multilayer film. Thicker PDDA/Al2O3-PEDOT:PSS films were elaborated when a drying step was added during the LbL build-up. The same effect was observed when composite particle concentration was increased from 1 to 10 g.L−1. Electrical behavior of film was completely modified in comparison with PDDA/PEDOT:PSS assembly. After heating at 150 °C, no conductivity was detected due to microcracks visible on SEM images. For SiO2-P3HT/PEDOT:PSS assembly, thickness is higher than for PDDA/Al2O3-PEDOT:PSS assembly using the same experimental procedure. However, even if two conductive polyelectrolytes were embedded into the film, conductivity was too low at 30 °C to be measured by van der Pauw technique probably due to the cracking of the film induced by incorporation of silica particles.

This is an erratum to the paper ‘The Pristine survey – VI. The first three years of medium-resolution follow-up spectroscopy of Pristine EMP star candidates’ (2019, MNRAS, 490, 2241–2253). In the original version of this paper, the author Rafael Garcia-Dias was incorrectly listed. This has now been corrected and the author’s apologise for the error.

Xylem vulnerability to drought-induced embolism did not differ between stems and petioles of four woody species ( Betula pendula , Liriodendron tulipifera , Populus tremula and Olea europaea ). Our results, together with data compiled from published literature, indicate that hydraulic segmentation during drought stress is not consistently driven by difference in vulnerability to embolism between stem and terminal organs. Hydraulic failure and disconnection of distal organs during protracted drought stress is thought to protect large branches or trunks by reducing water loss and restricting the spread of embolism. Hydraulic segmentation and preferential sacrifice of distal organs such as leaves can be driven by two mechanisms: more negative water potentials at the terminal section of the hydraulic pathway and/or by higher vulnerability to xylem embolism of distal organs. Although vulnerability segmentation has been reported in the literature, the generality of this phenomenon is unclear, in part due to the methodological limitations related to direct measurement of xylem vulnerability to embolism in intact plants. The objective of this study was to evaluate vulnerability segmentation between petioles and stems using non-invasive micro computed tomography (microCT). Vulnerability to embolism was measured in leaf petioles and subtending stems of four woody species (Betula pendula R., Liriodendron tulipifera L., Populus tremula L. and Olea europaea L.) with contrasting drought tolerances. In addition, previously published vulnerability data for petioles and stems were compiled from the literature to investigate the commonality of hydraulic segmentation across a wide range of woody species, with the vulnerability curve methodology distinguished. Using non-invasive imaging on intact plants, we found no evidence of hydraulic segmentation between petioles and stems of four angiosperm tree species, regardless of mechanism. Moreover, the literature dataset indicated that little or no difference in vulnerability to embolism is present between petioles and stems when vulnerability curves were constructed using methods specifically measuring the dynamics of xylem tissue during dehydration (e.g. optical visualization, MicroCT). Our results suggest that vulnerability segmentation between stems and distal organs (petioles and leaves) is limited when only xylem tissue is considered. Large differences in vulnerability between stems and leaves are likely to be driven by extra-xylary components, rather than xylem embolism.

The time and location of the 1,598 verified and reconstructed elves, used for the analysis showcased in this paper, are publicly available on the website of the Pierre Auger Observatory (https://www.auger.org/ index.php/science/data). We wish to thank the World Wide Lightning Location Network (http://wwlln.net), a collaboration among over 50 universities and institutions, for providing the lightning location data used in this paper. We acknowledge Robert Marshall for providing one of the most advanced elve simulations to the public, a key tool in understanding the elves observed by the Pierre Auger Observatory. The successful installation, commissioning, and operation of the Pierre Auger Observatory would not have been possible without the strong commitment and effort from the technical and administrative staff in Malargüe., Elves are a class of transient luminous events, with a radial extent typically greater than 250 km, that occur in the lower ionosphere above strong electrical storms. We report the observation of 1,598 elves, from 2014 to 2016, recorded with unprecedented time resolution (100 ns) using the fluorescence detector (FD) of the Pierre Auger Cosmic-Ray Observatory. The Auger Observatory is located in the Mendoza province of Argentina with a viewing footprint for elve observations of 3 · 106 km2, reaching areas above the Pacific and Atlantic Oceans, as well as the Córdoba region, which is known for severe convective thunderstorms. Primarily designed for ultrahigh energy cosmic-ray observations, the Auger FD turns out to be very sensitive to the ultraviolet emission in elves. The detector features modified Schmidt optics with large apertures resulting in a field of view that spans the horizon, and year-round operation on dark nights with low moonlight background, when the local weather is favorable. The measured light profiles of 18% of the elve events have more than one peak, compatible with intracloud activity. Within the 3-year sample, 72% of the elves correlate with the far-field radiation measurements of the World Wide Lightning Location Network. The Auger Observatory plans to continue operations until at least 2025, including elve observations and analysis. To the best of our knowledge, this observatory is the only facility on Earth that measures elves with year-round operation and full horizon coverage., Argentina—Comisión Nacional de Energía Atómica; Agencia Nacional de Promoción Científica y Tecnológica (ANPCyT); Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET); Gobierno de la Provincia de Mendoza; Municipalidad de Malargüe; and NDM Holdings and Valle Las Leñas, in gratitude for their continuing cooperation over land access; Australia—the Australian Research Council; Brazil—Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Financiadora de Estudos e Projetos (FINEP); Fundação de Amparo à Pesquisa do Estado de Rio de Janeiro (FAPERJ); São Paulo Research Foundation (FAPESP) Grants 2010/07359-6 and 1999/05404-3; Ministério da Ciência, Tecnologia, Inovações e Comunicações (MCTIC); Czech Republic—Grants MSMT CRLTT18004, LO1305, LM2015038, and CZ.02.1.01/0.0/0.0/16_013/0001402; France—Centre de Calcul IN2P3/CNRS; Centre National de la Recherche Scientifique (CNRS); Conseil Régional Ile-de-France; Département Physique Nucléaire et Corpusculaire (PNC-IN2P3/CNRS); Département Sciences de l'Univers (SDU-INSU/CNRS); Institut Lagrange de Paris (ILP) Grant LABEX ANR-10-LABX-63 within the Investissements d'Avenir Programme Grant ANR-11-IDEX-0004-02; Germany—Bundesministerium für Bildung und Forschung (BMBF); Deutsche Forschungsgemeinschaft (DFG); Finanzministerium Baden-Württemberg; Helmholtz Alliance for Astroparticle Physics (HAP); Helmholtz-Gemeinschaft. Deutscher Forschungszentren (HGF); Ministerium für Innovation, Wissenschaft und Forschung des Landes Nordrhein-Westfalen; Ministerium für Wissenschaft, Forschung und Kunst des Landes Baden-Württemberg; Italy—Istituto Nazionale di Fisica Nucleare (INFN); Istituto Nazionale di Astrofisica (INAF); Ministero dell'Istruzione, dell'Universitá e della Ricerca (MIUR); CETEMPS Center of Excellence; Ministero degli Affari Esteri (MAE); México—Consejo Nacional de Ciencia y Tecnología (CONACYT)167733; Universidad Nacional Autónoma de México (UNAM); PAPIIT DGAPA-UNAM; The Netherlands—Ministry of Education, Culture and Science; Netherlands Organisation for Scientific Research (NWO); Dutch National e-Infrastructure with the support of SURF Cooperative; Poland—National Centre for Research and Development, Grant ERA-NET-ASPERA/02/11; National Science Centre, Grants 2013/08/M/ST9/00322, 2016/23/B/ST9/01635, and HARMONIA 5–2013/10/M/ST9/00062, UMO-2016/22/M/ST9/00198; Portugal—Portuguese national funds and FEDER funds within Programa Operacional Factores de Competitividade through Fundação para a Ciência e a Tecnologia (COMPETE); Romania—Romanian Ministry of Research and InnovationCNCS/CCCDI-UESFISCDI, projects PN-III-P1-1.2-PCCDI-2017- 0839/19PCCDI/2018, PN-III-P2-2.1-PED-2016-1922, PN-III-P2-2.1-PED-2016-1659, and PN18090102 within PNCDI III; Slovenia—Slovenian Research Agency; Spain—Comunidad de Madrid; Fondo Europeo de Desarrollo Regional (FEDER) funds; Ministerio de Economía y Competitividad; Xunta de Galicia; European Community 7th Framework Program Grant FP7-PEOPLE-2012-IEF-328826; USA—Department of Energy, Contracts DE-AC02-07CH11359, DE-FR02-04ER41300, DE-FG02-99ER41107, and DE-SC0011689; National Science Foundation, Grant 0450696; The Grainger Foundation; Marie Curie-IRSES/EPLANET; European Particle Physics Latin American Network; European Union 7th Framework Program, Grant PIRSES-2009-GA-246806; and UNESCO.

International audience; In this paper, novel self-powered, solar-blind UV photodetector (PD) designs based on a ZnO thin-film with engineered back metal layer (BML) were fabricated by RF magnetron sputtering and e-beam evaporation techniques. An exhaustive study concerning the impact of dissimilar BML (Au and Ni) on the device structural, optical and electrical properties was carried out. The measured I–V curves illustrated an asymmetrical behavior, enabling a clear and distinctive photovoltaic mode. Superb sensitivity of 107, high ION/IOFF ratio of 149dB, ultralow dark-noise current less than 11pA and responsivity exceeding 0.27A/W were reached for the prepared ZnO-based UV-PDs in self-powered mode. The role of the engineered BML in promoting effective separation and transfer of the photo-induced carriers was discussed using the band-diagram theory. The influence of the annealing process on the UV-sensor performance was also investigated. The annealed device at 500°C demonstrated a lower dark current of a few picoamperes and a high rejection ratio of 2.2:103, emphasizing its exciting visible blindness characteristics. Therefore, the use of an engineered BML with optimized annealing conditions open up new perspectives to realizing high-performance, self-powered solar-blind UV-PDs based on simple thin film-ZnO structure strongly desirable for various optoelectronic applications.

Plasmonic Au nanoparticles (AuNPs) embedded into a TiO2 dielectric matrix were analyzed by combining two-dimensional and three-dimensional electron microscopy techniques. The preparation method was reactive magnetron sputtering, followed by thermal annealing treatments at 400 and 600 degrees C. The goal was to assess the nanostructural characteristics and correlate them with the optical properties of the AuNPs, particularly the localized surface plasmon resonance (LSPR) behavior. High-angle annular dark field scanning transmission electron microscopy results showed the presence of small-sized AuNPs (quantum size regime) in the as-deposited Au-TiO2 film, resulting in a negligible LSPR response. The in-vacuum thermal annealing at 400 degrees C induced the formation of intermediate-sized nanoparticles (NPs), in the range of 10-40 nm, which led to the appearance of a well-defined LSPR band, positioned at 636 nm. Electron tomography revealed that most of the NPs are small-sized and are embedded into the TiO2 matrix, whereas the larger NPs are located at the surface. Annealing at 600 degrees C promotes a bimodal size distribution with intermediate-sized NPs embedded in the matrix and big sized NPs, up to 100 nm, appearing at the surface. The latter are responsible for a broadening and a redshift, to 645 nm, in the LSPR band because of increase of scattering-to-absorption ratio. Beyond differentiating and quantifying the surface and embedded NPs, electron tomography also provided the identification of "hot-spots". The presence of NPs at the surface, individual or in dimers, permits adsorption sites for LSPR sensing and for surface-enhanced spectroscopies, such as surface enhanced Raman scattering., The authors thank the METSA network (FR3507 CNRS) for the financial support for this work, the Clym consortium for granting access to the Jeol 2010F and TITAN 80-300 keV ETEM. S.K. thanks the French Ministry of Higher Education and Research for the financial support during his PhD which was also supported by the LABEX iMUST (ANR-10-LABX-0064) of Universite de Lyon, within the program "Investissements d'Avenir" (ANR-11-IDEX-0007) operated by the French National Research Agency (ANR). This research was partly supported by the 3Dclean ANR-15-CE09-0009 project granted by the ANR. This research was also sponsored by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2013 and FCT Project 9471-RIDTI, co-funded by FEDER and with reference PTDC/FIS-NAN/1154/2014. J.B. acknowledges FCT for his Postdoc Grant (SFRH/BPD/117010/2016) and M.S.R. acknowledges FCT for his PhD Grant (SFRH/BD/118684/2016)., info:eu-repo/semantics/publishedVersion

International audience; High-resolution meteorological data are necessary to understand and predict climate-driven impacts on the structure and function of terrestrial ecosystems. However, the spatial resolution of climate reanalysis data and climate model outputs is often too coarse for studies at local/landscape scales. Additionally, climate model projections usually contain important biases, requiring the application of statistical corrections. Here we present 'meteoland', an R package that integrates several tools to facilitate the estimation of daily weather over landscapes, both under current and future conditions. The package contains functions: (1) to interpolate daily weather including topographic effects; and (2) to correct the biases of a given weather series (e.g., climate model outputs). We illustrate and validate the functions of the package using weather station data from Catalonia (NE Spain), re-analysis data and climate model outputs for a specific county. We conclude with a discussion of current limitations and potential improvements of the package.

Conductive polyelectrolyte multilayer films composed of conductive anionic poly(3,4-ethylenedioxythiophene): polystyrene sulfonate (PEDOT:PSS) and insulating cationic polydiallyldimethylammonium chloride (PDDA) were successfully prepared by layer-by-layer method. The (PDDA/PEDOT:PSS)n multilayer thickness is affected by the PDDA concentration ranging from 0.25 g.L−1 to 1 g.L−1 as well as the number of deposited bilayers and the type of salts used as electrolyte (BaCl2 or NaCl). More precisely, film thickness measured by profilometry increases with PDDA concentration, number of adsorbed bilayers and with the presence of Ba2+ cations. From UV–Visible absorbance spectroscopy, we showed that the amount of adsorbed PEDOT:PSS is greater when PDDA concentration increases and that PEDOT is still incorporated into the multilayer film especially when divalent ions are employed to improve the film growth. Water contact angles were measured on (PDDA/PEDOT:PSS)n films with PEDOT:PSS as the outerlayer. Films are more hydrophobic in the presence of Ba2+ which is probably due to a modification of the PEDOT:PSS core/shell structure. A percolation threshold leading to electrical conduction was determined as a function of the number of adsorbed bilayers. The effect of several parameters such as PDDA concentration, type of salt and temperature on conductivity and activation energy was investigated.

Fabrication of compartmentalised chemical systems with nested architectures and biomimetic properties has important implications for controlling the positional assembly of functional components, spatiotemporal regulation of enzyme cascades and modelling of proto-organelle behaviour in synthetic protocells. Here, we describe the spontaneous capture of glucose oxidase-containing proteinosomes in pH-sensitive fatty acid micelle coacervate droplets as a facile route to multi-compartmentalised host–guest protocells capable of antagonistic chemical and structural coupling. The nested system functions co-operatively at low-substrate turnover, while high levels of glucose give rise to pH-induced disassembly of the droplets, release of the incarcerated proteinosomes and self-reconfiguration into spatially organised enzymatically active vesicle-in-proteinosome protocells. Co-encapsulation of antagonistic enzymes within the proteinosomes produces a sequence of self-induced capture and host–guest reconfiguration. Taken together, our results highlight opportunities for the fabrication of self-reconfigurable host–guest protocells and provide a step towards the development of protocell populations exhibiting both synergistic and antagonistic modes of interaction., Multi-compartmentalised soft micro-systems are used as models of synthetic protocells. Here, the authors developed nested host–guest protocell constructs capable of self-reconfiguration in response to changes in pH generated by antagonistic modes of enzyme-mediated coupling.

Tungsten oxide thin films are grown by DC reactive magnetron sputtering combining glancing angle deposition (GLAD) and reactive gas pulsing process (RGPP). Inclined, zigzag and spiral columnar architectures are produced with various oxygen injections during the growth. The dodecane and ozone sensing properties of these tungsten oxide nanostructured active layers are comparatively studied with that of films deposited by conventional sputtering process. Microstructure, morphologies and electrical behaviors are characterized as a function of the growing conditions. As-deposited films systematically exhibit an amorphous crystal structure with a porous microstructure, which depends on the GLAD architecture. Annealing at 300 °C in air for 12 h leads to a polycrystalline structure keeping voided networks. Dodecane and ozone sensing performances are the most significant for inclined columnar architectures but they also depend on the RGPP sputtering conditions. As a result, the GLAD + RGPP combination proves to be a relevant strategy for the fabricating tungsten oxide nanostructured films as active layers with an attractive potential for gas sensors.

International audience; Tungsten oxide thin films were prepared by DC magnetron sputtering. The reactive gas pulsing processwas implemented to modify tungsten and oxygen concentrations in the films. A rectangular pulsingsignal was used with a pulsing period fixed at P ¼ 16 s, whereas the duty cycle a was systematicallychanged from a ¼ 0e100% of P. The chemical composition of the films showed a gradual increase ofoxygen-to-tungsten concentrations ratio from 0 to more than 3.0 as a function of the duty cycle. Filmsbecame poorly crystallized and even amorphous with an increase of the oxygen content. Similarly, atypical columnar structure was observed for pure or oxygen-rich tungsten films, which vanished whenthe duty cycle was higher than a few % of P. The optical transmittance in the visible range of WOx filmsdeposited on glass also showed a progressive change from absorbent to transparent as the duty cycle wasincreased. Electronic transport properties including conductivity, carrier mobility and concentration alsodemonstrated the controlled and regular evolution of the electrical properties from metallic to insulatorwhen the duty cycle and thus oxygen concentration in the films changed from pure tungsten to overstoichiometricWO3 compound.

Supercritical water (SCW) is widely known to be a powerful gasifying agent, but the supercritical gasification of linear paraffins is a method whose ability to produce H2 has not been studied significantly. Herein, an analysis of the gasification of dodecane, a representative diesel compound, with steam and SCW and the ability of the method to produce H2 under different pressures is reported. In this study, the broadest pressure (1–500 bar) and temperature (550–800 °C) ranges ever studied in this field are covered. We found that a fraction of the short-chain hydrocarbons generated in the thermal cracking of dodecane are turned into polycyclic aromatic compounds and phenol, compounds that hinder gasification. These reactions become more significant as steam at atmospheric pressure is progressively compressed up to SCW at 500 bar; consequently, steam gasification is faster than supercritical gasification. A gasification mechanism that gathers all of the possible pathways is proposed. Despite the slow gasification kinetics in SCW, a pressure slightly above the critical point (250 bar) is the most efficient to produce H2. At this pressure, the long reaction times related to the high SCW density allow a significant amount of CH4 and CO to be reformed into H2; however, further compression is not recommended because gasification is significantly slowed down and H2 production decreases.

Electrical resistivity of tilted columnar thin films is theoretically and experimentally investigated considering the anisotropic structure of the columns. To this end, W and W Cu thin films were deposited by the GLAD co-sputtering technique. These films were prepared using two different sputtering pressures: 2.5 × 10−3 and 15 × 10−3 mbar. Their morphological and crystallographic properties were studied in order to understand the correlations between some structural characteristics and electrical behaviors of these structured films. The influence of the sputtering pressure on the film's morphology was demonstrated and related to the electronic transport properties in these columnar films. For W Cu films, the copper was chemically etched in order to tune even more the electrical properties. By rotating the sample along its azimuthal axis, it was shown that the measured resistivity in the axis perpendicular to the particle flux is maximum, but decreases significantly along the axis parallel to the flux, leading to an anisotropic resistivity coefficient higher than 1.9 for some films. Similarly, an analytical model based-on effective medium approximations was successfully applied to determine the evolution of electrical resistivity versus azimuthal axis for W, W Cu and etched W Cu thin films.

We report on a successful attempt to introduce Al 2 O 3 and AlN nanoparticles in the matrix of a C/C composite via (i) aqueous synthesis of AlOOH nanoparticles in a predensified C/C composite preform, (ii) ceramization of AlOOH into either Al 2 O 3 or AlN, and (iii) final pyrocarbon densification. We show that we were able to synthesize a uniform and thin layer of high aspect ratio (nanoneedle) AlOOH particles at the surface of pyrocarbon coated fibers. This morphology was conserved upon transformation to alumina, however, coalescence into larger compact grains (thus discontinuous) was observed after nitridation. Nevertheless, the ceramic introduction did not alter the microstructure of the resulting composite after full densification. While most of the ceramic/carbon interfaces showed a parallel arrangement of graphene layers at the surface of the ceramic particles, characteristic of weak bonding, a carbon/AlN interface showed a perpendicular arrangement, suggesting strong covalent bonding.

UMR BFP - Equipe Mollicutes; International audience; We report on the formation of surfactant-based complex catanionic coacervate droplets in mixtures of decanoic acid and cetylpyridinium chloride or cetyltrimethylammonium bromide. We show that coacervation occurs over a broad range of composition, pH, and ionic strength. The catanionic coacervates consist of elongated micelles, sequester a wide range of solutes including water-soluble organic dyes, polysaccharides, proteins, enzymes, and DNA, and can be structurally stabilized by sodium alginate or gelatin-based hydrogelation. These results suggest that catanionic coacervates could be exploited as a novel surfactant-based membrane- free protocell model.

For green sustainable chemistry, it is crucial to investigate the destruction of such a common pollutant as phenol. This study reports the gasification of phenol with steam and supercritical water (SCW) and shows that gasification under high-pressure SCW is a method that destroys and efficiently converts phenol into valuable products. To the best of our knowledge, the widest pressure range ever investigated in this field is utilized, i.e., from atmospheric pressure steam to SCW at 1000 bar. The high temperature used (700 °C) leads to fast degradation of phenol under all the conditions studied but the amount of phenol gasified does strongly depend on pressure. During gasification, polymeric compounds such as naphthalene and phenanthrene are generated. They play a key role in the proposed degradation–gasification mechanism since they are difficult to degrade and can lead to the formation of char. High-pressure SCW can more efficiently degrade and gasify such polymeric compounds compared to steam. Then, the supercritical fluid leads to the conversion of a greater amount of phenol into gas than steam: 68% of the pollutant is gasified at 750 bar and 700 °C after 16.5 min with no generation of pollutant by-products, except CO2. Furthermore, the gaseous stream contains the valuable green gases H2 and CH4. The use of highly compressed SCW implies not only the production of more gases but also the enrichment of the gas mixture in H2 and CH4. H2 and CH4 concentrations up to 35 and 30%, respectively, are obtained at 1000 bar.

International audience; Coacervate micro-droplets produced by liquid-liquid phase separation have been used as synthetic protocells that mimic the dynamical organization of membrane-free organelles in living systems. Achieving spatiotemporal control over droplet condensation and disassembly remains challenging. Herein, we describe the formation and photo-switchable behaviour of light-responsive coacervate droplets prepared from mixtures of double-stranded DNA and an azobenzene cation. The droplets disassemble and reassemble under UV and blue light, respectively, due to azobenzene trans/cis photo-isomerisation. Sequestration and release of captured oligonucleotides follows the dynamics of phase separation such that light-activated transfer, mixing, hybridization and trafficking of the oligonucleotides can be controlled in binary populations of the droplets. Our results open perspectives for the spatiotemporal control of DNA coacervates and provide a step towards the dynamic regulation of synthetic protocells.

Light polarization is a key factor of modern photonics. Tailoring surface plasmons (SPs) in anisotropically-shaped metallic nanostructures introduces the prospect of polarization control at small scale [1]. However, the resulting components remain much larger than the wavelength of light. Here, we present a travelling-wave helical plasmonic antenna (TW-HPA) that overcomes this limit [2]. Due to its non-resonant nature, it differs from existing helical plasmonic structures [3–5], thus extending the concept of travelling-wave helical antenna [6] to optics.

In this work, a versatile method is proposed to increase the sensitivity of optical sensors based on the localized surface plasmon resonance (LSPR) phenomenon. It combines a physical deposition method with the oblique angle deposition technique, allowing the preparation of plasmonic thin films with tailored porosity. Thin films of Au-TiO2 were deposited by reactive magnetron sputtering in a 3D nanostructure (zigzag growth), at different incidence angles (0° ≤ α ≤ 80°), followed by in-air thermal annealing at 400 °C to induce the growth of the Au nanoparticles. The roughness and surface porosity suffered a gradual increment by increasing the incidence angle. The resulting porous zigzag nanostructures that were obtained also decreased the principal refractive indexes (RIs) of the matrix and favoured the diffusion of Au through grain boundaries, originating broader nanoparticle size distributions. The transmittance minimum of the LSPR band appeared at around 600 nm, leading to a red-shift to about 626 nm for the highest incidence angle α = 80°, due to the presence of larger (scattering) nanoparticles. It is demonstrated that zigzag nanostructures can enhance adsorption sites for LSPR sensing by tailoring the porosity of the thin films. Atmosphere controlled transmittance-LSPR measurements showed that the RI sensitivity of the films is improved for higher incidence angles., This research was sponsored by the Portuguese Foundation for Science and Technology (FCT) in the framework of Strategic Funding UID/FIS/04650/2013; project POCI-01-0145-FEDER-016902, with FCT reference PTDC/FIS-NAN/1154/2014; and project POCI-01-0145-FEDER-032299, with FCT reference PTDC/FIS-MAC/32299/2017. This work was also developed within the scope of the project CICECO-Aveiro Institute of Materials, FCT Ref. UID/CTM/50011/2019, financed by national funds through the FCT/MCTES. Manuela Proença acknowledges her PhD grant from FCT, with reference SFRH/BD/137076/2018. Joel Borges acknowledges FCT for his Post-Doc grant SFRH/BPD/117010/2016. Marco S Rodrigues acknowledges FCT for his PhD grant with reference SFRH/BD/118684/2016. Konstantin Romanyuk wish to thank the Portuguese FCT for the financial support (grant SFRH/BPD/88362/2012)., info:eu-repo/semantics/publishedVersion

International audience; Living cells have long been a source of inspiration for chemists. Their capacity of performing complex tasks relies on the spatiotemporal coordination of matter and energy fluxes. Recent years have witnessed growing interest in the bottom-up construction of cell-like models capable of reproducing aspects of such dynamic organisation. Liquid-liquid phase-separation (LLPS) processes in water are increasingly recognised as a viable compartmentalisation strategy through which to produce dynamic synthetic cells. Herein, we highlight examples of the dynamic properties of LLPS used to assemble synthetic cells, including their biocatalytic activity, reversible condensation and dissolution, growth and division, and recent directions towards the design of higher-order structures and behaviour.

"Available online 08 April 2019", Nanocomposite thin films, composed of monometallic Au and Ag, and bimetallic AuAg nanoparticles, dispersed in a CuO matrix were prepared, characterised and tested for Localized Surface Plasmon Resonance (LSPR) sensing. The films were deposited by reactive magnetron sputtering, followed by a post-deposition thermal annealing to modify the size and shape of the nanoparticles distribution within the oxide matrix. Regarding the main results of the monometallic systems, the Au:CuO films showed LSPR bands from 800 nm to 650 nm, which reveal a progressive narrowing and a continuous blue-shift with increasing temperature (400–700 °C). The Ag:CuO films evidenced plasmonic bands at about 400 nm for temperatures of 500 °C and above. The bimetallic system, Au-Ag:CuO, showed LSPR bands in the range between those of the corresponding monometallic systems, due to the presence of Ag enriched AuAg alloy nanoparticles, taking part of Janus-like structures in some cases. In terms of LSPR sensing, Au:CuO films revealed the highest values of refractive index sensitivity since the nanoparticles are more exposed to the surrounding environment., This work was supported by the Portuguese Foundation for Scienceand Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2019; and by the projects NANOSENSING, POCI-01-0145-FEDER-016902, with FCT reference PTDC/FIS-NAN/1154/2014; andNANO4BIO, POCI-01-0145-FEDER-032299, with FCT reference PTDC/FIS-MAC/32299/2017. Manuela Proença acknowledges her PhD grantfrom FCT, with reference SFRH/BD/137076/2018. Joel Borges ac-knowledges FCT for his Post-Doc grant SFRH/BPD/117010/2016.Marco S. Rodrigues acknowledges FCT for his PhD grant with referenceSFRH/BD/118684/2016. The authors would like to thank E. Alves(Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico,Universidade de Lisboa) and N. P. Barradas (Centro de Ciências eTecnologias Nucleares, Instituto Superior Técnico, Universidade deLisboa) for the RBS analysis., info:eu-repo/semantics/publishedVersion

Contents Summary 693 I. Introduction 693 II. Comparison of various definitions and measurement techniques of minimum conductance 694 III. Cuticular conductance 695 IV. Contribution of stomata 696 V. Environmental and ecological variation in minimum conductance 696 VI. Use of minimum conductance in models 698 VII. Conclusions 703 Acknowledgements 703 References 703 SUMMARY: When the rate of photosynthesis is greatly diminished, such as during severe drought, extreme temperature or low light, it seems advantageous for plants to close stomata and completely halt water loss. However, water loss continues through the cuticle and incompletely closed stomata, together constituting the leaf minimum conductance (gmin ). In this review, we critically evaluate the sources of variation in gmin , quantitatively compare various methods for its estimation, and illustrate the role of gmin in models of leaf gas exchange. A literature compilation of gmin as measured by the weight loss of detached leaves is presented, which shows much variation in this trait, which is not clearly related to species groups, climate of origin or leaf type. Much evidence points to the idea that gmin is highly responsive to the growing conditions of the plant, including soil water availability, temperature and air humidity - as we further demonstrate with two case studies. We pay special attention to the role of the minimum conductance in the Ball-Berry model of stomatal conductance, and caution against the usual regression-based method for its estimation. The synthesis presented here provides guidelines for the use of gmin in ecosystem models, and points to clear research gaps for this drought tolerance trait.

International audience; Mg-Sn thin films (21 ≤ at. % Sn ≤ 42.5) were deposited by magnetron sputtering in the argon atmosphere. The structure and morphology of the films were characterized as a function of the composition. Mg2Sn structure was changed from stable face-centered cubic to metastable orthorhombic structure while the content of Sn in the films increased. The influence of this structural modification on thermoelectric properties was discussed in a wide range of temperatures (30–200 °C). The film carrier concentration and mobility were measured to explain the electronic transport behavior as a function of the film structural modifications. The maximum figure of merit ZT ≈ 0.26 at 200 °C was reached for the film with 36 at. % Sn while a mixture of cubic and orthorhombic Mg2Sn structures coexisted. An annealing treatment was performed under vacuum (∼10−4 Pa) at different temperatures (up to 600 °C) to determine the limit of structural and morphological stability of this film.

This work reports on the preparation and characterization of zigzag nanostructured silver (Ag) doped zinc oxide (ZnO) films in order to improve piezoresistive response for pressure sensor applications. ZnO/Ag thin films were prepared by Glancing Angle Deposition (GLAD) from a metallic zinc (Zn) target DC sputtered in Ar + O2 atmosphere. The target was customized with different amounts of Ag pellets, symmetrically distributed along the preferential erosion area. It is shown that increasing the Ag content from 0 to 36 at.% in the ZnO/Ag system leads to a decrease of the electrical resistivity from 2.95 Ω cm to 1.52 × 10−5 Ω cm. The structural characterization of the thin films shows an evolution of the preferential growth, changing from a polycrystalline ZnO hexagonal-like structure, confirmed by the presence of dominant ZnO (002) and ZnO (101) diffraction peaks, to a Ag cubic (fcc)-like structure, as evidenced by the Ag (111), (200) and (220) diffraction peaks. The values of the gauge factor show a strong contribution both from Ag as well as from the zigzag nanostructure to the piezoresistive sensitivity of the films, in particular for Ag concentrations lower than 30 at.%. The tunneling distance between pairs of Ag conductive nanoregions was calculated for the different samples and in three different deformation regions, in order to evaluate its influence on the piezoresistive sensitivity. The results show that a longer distance between Ag particles, which varies from 0.1 to 10 nm, enhances the gauge factor, which ranges from 8 ± 1 to 120 ± 3, respectively., This work was supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2013 and project PTDC/EEI-SII/5582/2014. Armando Ferreira acknowledges the FCT for the SFRH/BPD/102402/2014 grant. Funding was also provided by the Region of Franche-Comté, the French RENATECH network. This work has also been supported by the EIPHI Graduate School (contract “ANR-17-EURE-0002”). Financial support from the Basque Government Industry Department under the ELKARTEK and HAZITEK programs is also acknowledged.