Microstructure of epitaxial strained BiCrO3 thin films

The structure and microstrucutre of fully-strained BiCrO3 thin films have been investigated by X-rays diffraction and transmission electron microscopy, at room temperature. Interestingly, three structural variants are simultaneously stabilized within the film. While txo of them are consistent with the existing phases in the bulk-below and above the 420 K structural transition, a different phase is identified. The existence of various structures has been attributed to the inhomogeneous distribution of local strains and oxygens resulting from a minimization of the strain-energy at the interface. These findings will open the route to a better understanding of Bi-based perovskites and metastable phases.Comment: 10 pages, 5 figures, to be published in Applied Physics Letter

Neonate Intestinal Immune Response to CpG Oligodeoxynucleotide Stimulation

Background: The development of mucosal vaccines is crucial to efficiently control infectious agents for which mucosae are the primary site of entry. Major drawbacks of these protective strategies are the lack of effective mucosal adjuvant. Synthetic oligodeoxynucleotides that contain several unmethylated cytosine-guanine dinucleotide (CpG-ODN) motifs are now recognized as promising adjuvants displaying mucosal adjuvant activity through direct activation of TLR9-expressing cells. However, little is known about the efficacy of these molecules in stimulating the intestinal immune system in neonates. Methodology/Principal Findings: First, newborn mice received CpG-ODN orally, and the intestinal cytokine and chemokine response was measured. We observed that oral administration of CpG-ODN induces CXC and CC chemokine responses and a cellular infiltration in the intestine of neonates as detected by immunohistochemistry. We next compared the efficiency of the oral route to intraperitoneal administration in stimulating the intestinal immune responses of both adults and neonates. Neonates were more responsive to TLR9-stimulation than adults whatever the CpG-ODN administration route. Their intestinal epithelial cells (IECs) indirectly responded to TLR9 stimulation and contributed to the CXC chemokine response, whereas other TLR9-bearing cells of the lamina-propria produced CC chemokines and Th1-type cytokines. Moreover, we showed that the intestine of adult exhibited a significantly higher level of IL10 at homeostasis than neonates, which might be responsible for the unresponsiveness to TLR9-stimulation, as confirmed by our findings in IL10-deficient mice. Conclusions/Significance: This is the first report that deciphers the role played by CpG-ODN in the intestine of neonates. This work clearly demonstrates that an intraperitoneal administration of CpG-ODN is more efficient in neonates than in adults to stimulate an intestinal chemokine response due to their lower IL-10 intestinal level. In addition we report the efficiency of the oral route at inducing intestinal chemokine responses in neonate that might be taken into consideration for further vaccine development against neonatal diseases

CO2 Adsorption/Desorption in FAU Zeolite Nanocrystals: In Situ Synchrotron X-ray Powder Diffraction and in Situ Fourier Transform Infrared Spectroscopic Study

International audienceThe host–guest and guest–guest interactions governing the CO2 adsorption/desorption in two nanosized zeolite samples with FAU framework type and different Si/Al ratios (Na–X Si/Al = 1.24 and Na–Y Si/Al = 2.54) and cation distribution were investigated by in situ synchrotron high-resolution X-ray powder diffraction (XRPD) and in situ Fourier transform infrared (FTIR) spectroscopy. The two complementary techniques allow probing the CO2 adsorption/desorption in the FAU zeolites at different levels, that is, average structure by XRPD versus local structure by FTIR spectroscopy . The presence of physisorbed CO2 molecules in both zeolites was detected by XRPD, whereas only a high amount of chemisorbed CO2 in the Na–X zeolite was found. The presence of unshielded Na cations and H2O molecules in the supercage of the Na–X sample induces the formation of stable bidentate bicarbonate groups. Evacuating CO2-loaded samples resulted in the efficient removal of physisorbed CO2 from both nanosized zeolites; on the contrary, high temperature is required to remove the chemisorbed species from the nanosized Na–X zeolite. Understanding the CO2 sorption behavior and capacity of nanosized zeolites is of great importance in broadening their use in environmental, clinical, and biomedical applications

An iron cycle cascade governs the response of equatorial Pacific ecosystems to climate change

Earth System Models project that global climate change will reduce ocean net primary production (NPP), upper trophic level biota biomass and potential fisheries catches in the future, especially in the eastern equatorial Pacific. However, projections from Earth System Models are undermined by poorly constrained assumptions regarding the biological cycling of iron, which is the main limiting resource for NPP over large parts of the ocean. In this study, we show that the climate change trends in NPP and the biomass of upper trophic levels are strongly affected by modifying assumptions associated with phytoplankton iron uptake. Using a suite of model experiments, we find 21st century climate change impacts on regional NPP range from −12.3% to +2.4% under a high emissions climate change scenario. This wide range arises from variations in the efficiency of iron retention in the upper ocean in the eastern equatorial Pacific across different scenarios of biological iron uptake, which affect the strength of regional iron limitation. Those scenarios where nitrogen limitation replaced iron limitation showed the largest projected NPP declines, while those where iron limitation was more resilient displayed little future change. All model scenarios have similar skill in reproducing past inter‐annual variations in regional ocean NPP, largely due to limited change in the historical period. Ultimately, projections of end of century upper trophic level biomass change are altered by 50%–80% across all plausible scenarios. Overall, we find that uncertainties in the biological iron cycle cascade through open ocean pelagic ecosystems, from plankton to fish, affecting their evolution under climate change. This highlights additional challenges to developing effective conservation and fisheries management policies under climate change

Next-generation ensemble projections reveal higher climate risks for marine ecosystems

Projections of climate change impacts on marine ecosystems have revealed long-term declines in global marine animal biomass and unevenly distributed impacts on fisheries. Here we apply an enhanced suite of global marine ecosystem models from the Fisheries and Marine Ecosystem Model Intercomparison Project (Fish-MIP), forced by new-generation Earth system model outputs from Phase 6 of the Coupled Model Intercomparison Project (CMIP6), to provide insights into how projected climate change will affect future ocean ecosystems. Compared with the previous generation CMIP5-forced Fish-MIP ensemble, the new ensemble ecosystem simulations show a greater decline in mean global ocean animal biomass under both strong-mitigation and high-emissions scenarios due to elevated warming, despite greater uncertainty in net primary production in the high-emissions scenario. Regional shifts in the direction of biomass changes highlight the continued and urgent need to reduce uncertainty in the projected responses of marine ecosystems to climate change to help support adaptation planning

Disentangling diverse responses to climate change among global marine ecosystem models

Climate change is warming the ocean and impacting lower trophic level (LTL) organisms. Marine ecosystem models can provide estimates of how these changes will propagate to larger animals and impact societal services such as fisheries, but at present these estimates vary widely. A better understanding of what drives this inter-model variation will improve our ability to project fisheries and other ecosystem services into the future, while also helping to identify uncertainties in process understanding. Here, we explore the mechanisms that underlie the diversity of responses to changes in temperature and LTLs in eight global marine ecosystem models from the Fisheries and Marine Ecosystem Model Intercomparison Project (FishMIP). Temperature and LTL impacts on total consumer biomass and ecosystem structure (defined as the relative change of small and large organism biomass) were isolated using a comparative experimental protocol. Total model biomass varied between −35% to +3% in response to warming, and -17% to +15% in response to LTL changes. There was little consensus about the spatial redistribution of biomass or changes in the balance between small and large organisms (ecosystem structure) in response to warming, an LTL impacts on total consumer biomass varied depending on the choice of LTL forcing terms. Overall, climate change impacts on consumer biomass and ecosystem structure are well approximated by the sum of temperature and LTL impacts, indicating an absence of nonlinear interaction between the models’ drivers. Our results highlight a lack of theoretical clarity about how to represent fundamental ecological mechanisms, most importantly how temperature impacts scale from individual to ecosystem level, and the need to better understand the two-way coupling between LTL organisms and consumers. We finish by identifying future research needs to strengthen global marine ecosystem modelling and improve projections of climate change impacts

L'échafaudage dans le chantier médiéval

Pour un professionnel qui taille la pierre depuis près de quarante ans, comment ne pas être reconnaissant à ceux qui, professeurs ou archéologues, recherchent avec tant de conviction la mémoire des techniques de la construction médiévale, ces techniques presque oubliées depuis l’abandon total de la construction en pierre. Nous avons de la peine à imaginer ces époques, car nous n’avons plus sous les yeux ni les chantiers, ni l’habileté des hommes de métier. De cette industrie de la pierre, la ..

The dehydration of SrTeO3(H2O) - a topotactic reaction for preparation of the new metastable strontium oxotellurate(IV) phase e-SrTeO3

Microcrystalline single-phase strontium oxotellurate(IV) monohydrate, SrTeO3 (H2O), was obtained by microwave-assisted hydrothermal synthesis under alkaline conditions at 180 ◦C for 30 min. A temperature of 220 ◦C and longer reaction times led to single crystal growth of this material. The crystal structure of SrTeO3 (H2O) was determined from single crystal X-ray diffraction data: P21/c, Z = 4, a = 7.7669(5), b = 7.1739(4), c = 8.3311(5)A˚ , b = 107.210(1)◦, V = 443.42(5)A˚ 3 , 1403 structure factors, 63 parameters, R[F2>2s(F2 )] = 0.0208, wR(F2 all) = 0.0516, S = 1.031. SrTeO3 (H2O) is isotypic with the homologous BaTeO3 (H2O) and is characterised by a layered assembly parallel to (100) of edge-sharing [SrO6 (H2O)] polyhedra capped on each side of the layer by trigonal-prismatic [TeO3 ] units. The cohesion of the structure is accomplished by moderate O–H ◊ ◊ ◊ O hydrogen bonding interactions between donor water molecules and acceptor O atoms of adjacent layers. In a topochemical reaction, SrTeO3 (H2O) condensates above 150 ◦C to the metastable phase e-SrTeO3 and transforms upon further heating to d-SrTeO3 . The crystal structure of e-SrTeO3 , the fifth known polymorph of this composition, was determined from combined electron microscopy and laboratory X-ray powder diffraction studies: P21/c, Z = 4, a = 6.7759(1), b = 7.2188(1), c = 8.6773(2)A˚ , b = 126.4980(7)◦, V = 341.20(18)A˚ 3 , RFobs = 0.0166, RBobs = 0.0318, Rwp = 0.0733, Goof = 1.38. The structure of e-SrTeO3 shows the same basic set-up as SrTeO3 (H2O), but the layered arrangement of the hydrous phase transforms into a framework structure after elimination of water. The structural studies of SrTeO3 (H2O) and e-SrTeO3 are complemented by thermal analysis and vibrational spectroscopic measurements.Centro de Química Inorgánic

Global ensemble projections reveal trophic amplification of ocean biomass declines with climate change

While the physical dimensions of climate change are now routinely assessed through multimodel intercomparisons, projected impacts on the global ocean ecosystem generally rely on individual models with a specific set of assumptions. To address these single-model limitations, we present standardized ensemble projections from six global marine ecosystem models forced with two Earth system models and four emission scenarios with and without fishing. We derive average biomass trends and associated uncertainties across the marine food web. Without fishing, mean global animal biomass decreased by 5% (±4% SD) under low emissions and 17% (±11% SD) under high emissions by 2100, with an average 5% decline for every 1 °C of warming. Projected biomass declines were primarily driven by increasing temperature and decreasing primary production, and were more pronounced at higher trophic levels, a process known as trophic amplification. Fishing did not substantially alter the effects of climate change. Considerable regional variation featured strong biomass increases at high latitudes and decreases at middle to low latitudes, with good model agreement on the direction of change but variable magnitude. Uncertainties due to variations in marine ecosystem and Earth system models were similar. Ensemble projections performed well compared with empirical data, emphasizing the benefits of multimodel inference to project future outcomes. Our results indicate that global ocean animal biomass consistently declines with climate change, and that these impacts are amplified at higher trophic levels. Next steps for model development include dynamic scenarios of fishing, cumulative human impacts, and the effects of management measures on future ocean biomass trends

Configuration files used in the ToE paper

<p>This dataset contains the configuration files to run the piControl-spinup experiment in the ToE paper.</p> <p>All the other simulations use the same configuration, except for the forcing and restart paths.</p> <p>The APECOSM version used is <code>c0a910b8</code>.</p> <p>PAR has been reconstructed from chlorophyll and solar radiation using the <a href="https://github.com/apecosm/par-calculation" target="_blank" rel="noopener">par-calculation</a> tool (version <code>58ab94c</code>)</p&gt