Decadal fates and impacts of nitrogen additions on temperate forest carbon storage: a data-model comparison

To accurately capture the impacts of nitrogen (N) on the land carbon (C) sink in Earth system models, model responses to both N limitation and ecosystem N additions (e.g., from atmospheric N deposition and fertilizer) need to be evaluated. The response of the land C sink to N additions depends on the fate of these additions: that is, how much of the added N is lost from the ecosystem through N loss pathways or recovered and used to increase C storage in plants and soils. Here, we evaluate the C&ndash;N dynamics of the latest version of a global land model, the Community Land Model version 5 (CLM5), and how they vary when ecosystems have large N inputs and losses (i.e., an open N cycle) or small N inputs and losses (i.e., a closed N cycle). This comparison allows us to identify potential improvements to CLM5 that would apply to simulated N cycles along the open-to-closed spectrum. We also compare the short- (&lt;&thinsp;3 years) and longer-term (5&ndash;17 years) N fates in CLM5 against observations from 13 long-term 15N tracer addition experiments at eight temperate forest sites. Simulations using both open and closed N cycles overestimated plant N recovery following N additions. In particular, the model configuration with a closed N cycle simulated that plants acquired more than twice the amount of added N recovered in 15N tracer studies on short timescales (CLM5: 46&plusmn;12&thinsp;%; observations: 18&plusmn;12&thinsp;%; mean across sites &plusmn;1 standard deviation) and almost twice as much on longer timescales (CLM5: 23&plusmn;6&thinsp;%; observations: 13&plusmn;5&thinsp;%). Soil N recoveries in simulations with closed N cycles were closer to observations in the short term (CLM5: 40&plusmn;10&thinsp;%; observations: 54&plusmn;22&thinsp;%) but smaller than observations in the long term (CLM5: 59&plusmn;15&thinsp;%; observations: 69&plusmn;18&thinsp;%). Simulations with open N cycles estimated similar patterns in plant and soil N recovery, except that soil N recovery was also smaller than observations in the short term. In both open and closed sets of simulations, soil N recoveries in CLM5 occurred from the cycling of N through plants rather than through direct immobilization in the soil, as is often indicated by tracer studies. Although CLM5 greatly overestimated plant N recovery, the simulated increase in C stocks to recovered N was not much larger than estimated by observations, largely because the model's assumed C:N ratio for wood was nearly half that suggested by measurements at the field sites. Overall, results suggest that simulating accurate ecosystem responses to changes in N additions requires increasing soil competition for N relative to plants and examining model assumptions of C:N stoichiometry, which should also improve model estimates of other terrestrial C&ndash;N processes and interactions.</p

Mechanical, pH and Thermal Stability of Mesoporous Hydroxyapatite

The stability of mesoporous hydroxyapatite (HAP) powder was studied following treatments of ultrasound, pH and heating. HAP was found to be mechanically stable up to (and including) 1 h continuous ultrasonic treatment in water. The HAP structure was also stable to pH, evidenced by practically identical XRD and FTIR spectra over the pH range 2–12. The surface area increased progressively with increasing acidity, reaching a maximum of 121.9 m 2 g −1 at pH 2, while alkaline conditions decreased the surface area to a minimum of 55.4 m 2 g −1 at pH 12. Heating in air had a significant influence on the structural and morphological properties of HAP, which underwent dehydroxylation to form oxyhydroxyapatite (OHAP) at temperatures ≥ 650 °C, and β-tricalcium phosphate (β-TCP) ≥750 °C. The surface area decreased at elevated temperatures due to agglomeration of HAP crystals by sintering, which was associated with an increased particle size

Etude endoscopique des lymphomes gastriques

This report on the macroscopic data yielded by fibergastroscopy and multiple sight controlled biopsies, in a series of 10 cases of gastric lymphomas, emphasizes the diagnostic value of the morphological characteristics observed on the lesion which, in all cases, had multiple localisations. In spite of repeated sample collection, the number of correct histological diagnoses is less than in gastric adenocarcinomas. Even if the authors' multiple gastric biopsies provide nearly as many accurate diagnoses as reached by other authors with the exfoliative cytology technique, this should not deter them from associating the two diagnostic methods.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

A new family of mono- and dicarboxylic ruthenium complexes [Ru(DIP)(2)(L-2)](2+) (DIP=4,7-diphenyl-1,10-phenanthroline): Synthesis, solution behavior, and X-ray molecular structure of trans-[Ru(DIP)(2)(MeOH)(2)][OTf](2)

9 pagesA new family of ruthenium complexes of general formula [Ru(DIP)(2)(L-2)](2+), where DIP) 4,7-diphenyl-1,10-phenanthroline,a bidentate ligand with an extended aromatic system, was prepared and fully characterized. When L is a monodentate ligand, the following complexes were obtained: L = CF3SO3-1 (2), CH3CN (3), and MeOH (4). When L-2 is a bidentate ligand, the compounds [Ru(DIP)(2)(Hcmbpy)][Cl](2) (5) and [Ru(DIP)(2)(H(2)dcbpy)][Cl](2) ( 6) were prepared (Hcmbpy = 4-carboxy-4'-methyl-2,2-bipyridine, H(2)dcbpy = 4,4'-dicarboxy-2,2'-bipyridine). Complex [Ru(DIP)(2)(MeOH)(2)][OTf](2) (4) displayed a trans configuration of the DIP ligands, which is rare for octahedral complexes featuring DIP bidentate ligands. DFT calculations carried out on 4 showed that the cis isomer is more stable by 12.2 kcal/ mol relative to the trans species. The solution behaviors of monocarboxylic complex [ Ru( DIP) 2( Hcmbpy)][Cl](2) ( 5) and dicarboxylic complex [Ru(DIP)(2)(H(2)dcbpy)][Cl](2) (6) were investigated by H-1 NMR spectroscopy. VT-NMR, concentration dependence, and reaction with NaOD allowed us to suggest that aggregation of the cationic species in solution, especially for 6, originates mainly from hydrogen bonding interactions

Strong magneto-chiral dichroism in enantiopure chiral ferromagnets

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