Toward an automatic full-wave inversion: Synthetic study cases

Full-waveform inversion (FWI) in seismic scenarios continues to be a complex procedure for subsurface imaging that might require extensive human interaction in terms of model setup, constraints, and data preconditioning. The underlying reason is the strong nonlinearity of the problem that forces the addition of a priori knowledge (or bias) in order to obtain geologically sound results. In particular, when the use of a long-offset receiver is not possible or may not favor the reconstruction of the fine structure of the model, one needs to rely on reflection data. As a consequence, the inversion process is more prone to becoming stuck in local minima. Nevertheless, misfit functionals can be devised that can either cope with missing long-wavenumber features of initial models (e.g., cross-correlation-based misfit) or invert reflection-dominated data whenever the models are sufficiently good (e.g., normalized offset-limited least-squares misfit). By combining both, high-frequency data content with poor initial models can be successfully inverted. If one can figure out simple parameterizations for such functionals, the amount of uncertainty and manual work related to tuning FWI would be substantially reduced. Thus, FWI might become a semiautomatized imaging tool.We want to thank Repsol for funding this research by means of the Aurora project. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 644202. Additionally, the research leading to these results has received funding from the European Union’s Horizon 2020 Programme (2014-2020) and from Brazilian Ministry of Science, Technology and Innovation through Rede Nacional de Pesquisa (RNP) under the HPC4E Project (www.hpc4e.eu), grant agreement No 689772. We acknowledge Chevron for the dataset that was used in our second example.Peer ReviewedPostprint (author's final draft

Assessing Overall Diet Quality: Development and Evaluation of the Performance of a Short Self-Administrated Questionnaire SCASA.

Several tools assessing diet quality have been developed over the last decades, but their use in public health and clinical practice is limited because they necessitate detailed quantitative assessment of food intake. Our goal was to develop and validate a score (Score d'Alimentation Saine, SCASA) based on a short self-administrated online questionnaire to assess overall diet quality. SCASA targets the adult population in French-speaking Switzerland, but it was designed in a way enabling its adaptation for other regions. The choice of the items involved experts and lay volunteers. Construct validation and inter-method reliability were assessed by screening meal plans and by comparing the self-rated scores with food-record derived scores (kappa and Bland-Altman). SCASA (17 components) discriminated adequately balanced from imbalanced meal plans (93-95% and 44-46% of maximal score). Agreement between self-assessed and food record-based scores ranged between >90% (3 items), 80-89% (3 items), 70-79% (4 items), and <70% (5 items). The Bland-Altman plot showed a mean difference of -1.60 (95% CI -2.36 to -0.84), indicating a slight overestimation of the self-assessed diet quality compared to the food record. SCASA offers a reliable way to assess overall diet quality without requiring burdensome data collection or nutrient calculations

Influence of storage environment on maize grain: CO2 production, dry matter losses and aflatoxins contamination

Poor storage of cereals, such as maize can lead to both nutritional losses and mycotoxin contamination. The aim of this study was to examine the respiration of maize either naturally contaminated or inoculated with Aspergillus flavus to examine whether this might be an early and sensitive indicator of aflatoxin (AF) contamination and relative storability risk. We thus examined the relationship between different interacting storage environmental conditions (0.80–0.99 water activity (aw) and 15–35°C) in naturally contaminated and irradiated maize grain + A. flavus on relative respiration rates (R), dry matter losses (DMLs) and aflatoxin B1 and B2 (AFB1-B2) contamination. Temporal respiration and total CO2 production were analysed by GC-TCD, and results used to calculate the DMLs due to colonisation. AFs contamination was quantified at the end of the storage period by HPLC MS/MS. The highest respiration rates occurred at 0.95 aw and 30–35°C representing between 0.5% and 18% DMLs. Optimum AFs contamination was at the same aw at 30°C. Highest AFs contamination occurred in maize colonised only by A. flavus. A significant positive correlation between % DMLs and AFB1 contamination was obtained (r = 0.866, p < 0.001) in the irradiated maize treatments inoculated with A. flavus. In naturally contaminated maize + A. flavus inoculum loss of only 0.56% DML resulted in AFB1 contamination levels exceeding the EU legislative limits for food. This suggests that there is a very low threshold tolerance during storage of maize to minimise AFB1 contamination. This data can be used to develop models that can be effectively used in enhancing management for storage of maize to minimise risks of mycotoxin contamination

Acceleration strategies for elastic full waveform inversion workflows in 2D and 3D

Full waveform inversion (FWI) is one of the most challenging procedures to obtain quantitative information of the subsurface. For elastic inversions, when both compressional and shear velocities have to be inverted, the algorithmic issue becomes also a computational challenge due to the high cost related to modelling elastic rather than acoustic waves. This shortcoming has been moderately mitigated by using high-performance computing to accelerate 3D elastic FWI kernels. Nevertheless, there is room in the FWI workflows for obtaining large speedups at the cost of proper grid pre-processing and data decimation techniques. In the present work, we show how by making full use of frequency-adapted grids, composite shot lists and a novel dynamic offset control strategy, we can reduce by several orders of magnitude the compute time while improving the convergence of the method in the studied cases, regardless of the forward and adjoint compute kernels used.The authors thank REPSOL for the permission to publish the present research and for funding through the AURORA project. J. Kormann also thankfully acknowledges the computer resources, technical expertise and assistance provided by the Barcelona Supercomputing Center - Centro Nacional de Supercomputacti ´on together with the Spanish Supercomputing Network (RES) through grant FI-2014-2-0009. This project has received funding from the European Union’s Horizon 2020, research and innovation programme under the Marie Skłodowska-Curie grant agreement no. 644202. The research leading to these results has received funding from the European Union’s Horizon 2020 Programme (2014–2020) and from the Brazilian Ministry of Science, Technology and Innovation through Rede Nacional de Pesquisa (RNP) under the HPC4E Project (www.hpc4e.eu), grant agreement no. 689772.We further want to thank the Editor Clint N. Dawson for his help, and Andreas Fichtner and an anonymous reviewer for their comments and suggestions to improve the manuscript.Peer ReviewedPostprint (published version

NiO–CGO in situ nanocomposite attainment: One step synthesis

AbstractThe CeO2-based electrolyte low temperature SOFCs require special electrodes with a higher performance and compatibility. The performance of the CeO2-based composite anodes depends on microstructural features such as particle size, tripe phase boundaries (TPB), surface area, and percolation. Some of the primary parameter can be manipulated during the materials synthesis. In this work the compound NiO–Ce0.9Gd0.1O1.95 (NiO–CGO), used as anode in SOFC, was synthesized by two different processes. Both of them are based on the polymeric precursor method. Characterized by simultaneous thermogravimetry-differential thermal analysis, X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy and dilatometry. The refinement of the XRD data indicated that the composite sample synthesized by the process called “one step synthesis” produced smaller crystallite size in comparison to the sample attained by the two steps process. Simple preliminary performance tests were done with single cells in which such I–V curves indicated that the cell with one step anode had better performance. “One step synthesis” product, in situ nanocomposite, presented similar fine grained particle sizes for both phases Ni and CGO, which would be beneficial to the electrochemical activity, also indicated by first performance tests

Sulfadiazine, sulfamethazine and sulfachloropyridazine removal using three different porous materials: Pine bark, “oak ash” and mussel shell

This work focuses on studying the efficacy of three different by-products to adsorb three antibiotics (sulfadiazine, SDZ; sulfamethazine, SMT; sulfachloropyridazine, SCP). These antibiotics can be considered pollutants of the environment when they reach water, as well as in cases where they are spread on soils through irrigation or contained in sewage sludge or livestock manure. In this study, batch-type adsorption/desorption experiments were performed for each of the three sulfonamides, adding 7 different concentrations of the antibiotics, going from 1 to 50 μmol L−1, and with contact time of 24 h. The results indicate that pine bark is the most efficient bioadsorbent among those studied, as it adsorbs up to 95% of the antibiotics added, while desorption is always less than 11%. However, for “oak ash” and mussel shell the adsorption is always lower than 45 and 15%, respectively, and desorption is high, reaching up to 49% from “oak ash” and up to 81% from mussel shell. Adsorption data showed good fitting to the Linear and Freundlich models, with R2 values between 0.98 and 1.00 in both cases. Kd and KF adsorption parameters showed similar values for the same sorbent materials but were much higher for pine bark than for the other two bioadsorbents. The Freundlich's n parameter showed values in the range 0.81–1.28. The highest KF values (and therefore the highest adsorption capacities) were obtained for the antibiotic SCP in pine bark. Pine bark showed the highest capacity to adsorb each of the antibiotics, increasing as a function of the concentration added. When the concentration of sulfonamide added was 50 μM, the amounts adsorbed were 780 μmol kg−1 for SDZ, 890 μmol kg−1 for SMT, and 870 μmol kg−1 for SCP. “Oak ash” and mussel shell have low adsorption capacity for all three sulfonamides, showing values always lower than 150 μmol kg−1 (oak ash) and 20 μmol kg−1 (mussel shell) when a concentration of 50 μmol L−1 of antibiotic is added. The results of this study could aid to make an appropriate management of the by-products studied, in order to facilitate their valorization and recycling in the treatment of environmental compartments polluted with sulfonamide antibiotics.Agencia Estatal de Investigación | Ref. RTI2018-099574-B-C21Agencia Estatal de Investigación | Ref. RTI2018-099574-B-C2

Risk factors for diabetic foot ulcers: An Albanian retrospective study of inpatients with type 2 diabetes

OBJECTIVE: The aim of this study was to assess the impact of glucose control, diabetes-related complications and cardiometabolic risk factors on the risk of diabetic foot ulcers (DFUs) and DFU complications in Albanian adult inpatients with T2D.PATIENTS AND METHODS: We conducted a retrospective case-control study on 482 Albanian adult inpatients with T2D. DFU was defined as a full-thickness skin lesion requiring &gt;= 14 days for healing and was classified at the time of hospital admission. Demographic and biochemical parameters of the study participants, the presence of comorbidities and diabetes -related complications at the time of hospital admission were evaluated through a retrospective chart review.RESULTS: Mean age of study participants was 54.8 +/- 10.7 years. Participants (284 males and 198 females) were divided into two groups: DFU (cases; n=104) and non-DFU (controls; n=378). Multivariate analysis (performed by a logistic regression model) revealed that the most relevant independent variables associated with DFU were BMI [OR= 0.62; p=0.007], HDL-cholesterol [OR=0.00; p&lt;0.0001], triglycerides [OR=7.48; p=0.0004], cigarette smoking [OR=26.46; p=0.005], duration of diabetes [OR=1.53; p&lt;0.0001], fasting plasma glucose (FPG) [OR=1.06; p&lt;0.0001], systolic blood pressure (SBP) [OR=1.13; p=0.0004] and insulin therapy alone [OR=0.11; p=0.02]. ROC curve analysis showed that FPG (AUC=0.83), glycated hemoglobin (HbA1c) (AUC=0.75), triglycerides (AUC=0.78) and HDL-cholesterol (AUC=0.82) were the most reliable biomarkers able to detect DFU. In the DFU group, the most relevant independent variables associated with previous minor lower-extremity amputations (LEAs) were represented by HbA1c [OR=1.47; p=0.03], age &lt;55 years [OR=0.12; p=0.0 5] and female sex [OR=4.18; p=0.03]; whereas the most relevant independent variables associated with diabetic peripheral neuropathy (DPN) were HbA1c [OR=1.70; p=0.006], SBP [OR=1.08; p=0.05], BMI [OR=1.20; p=0.03] and lack of cigarette smoking [OR=0.07; p=0.01]. Correlation analysis (performed through the nonparametric Spearman's rank correlation test or through the parametric Pearson test, as appropriate) revealed a significant positive relationship between HbA1c and FPG (r=0.58; p&lt;0.0001), ulcer surface area (r=0.50; p&lt;0.0001), ulcer grade (r= 0.23; p=0.02), minor LEAs (r=0.20; p=0.04), DPN (r=0.41; p&lt;0.0001), and metformin therapy alone (r=0.72; p&lt;0.0001). There was a significant inverse correlation between HbA1c and insulin therapy alone (r=-0.31; p=0.01) and combined metformin and insulin therapy (r=-0.60; p&lt;0.0001). Both DFU and non-DFU groups exhibited suboptimal mean LDL-cholesterol levels (&gt;100 mg/dl) and mean HbA1c values &gt;7.5%. Moreover, in DFU group HbA1c values were markedly elevated (&gt;= 10%) particularly in patients with a grade 3 ulcer and an ulcer surface area &gt;= 4 cm2, as well as in patients with history of minor LEAs and in patients affected by DPN.CONCLUSIONS: The present study suggested that longer duration of diabetes, cigarette smoking, lower HDL-cholesterol levels, poor glucose control, and elevated triglyceride and SBP values may all represent major risk factors for the development of DFU in Albanian patients with T2D. Thus, community interventions and health policies aimed to improve the management of diabetes and related cardiometabolic risk factors should be urgently implemented in Albania, in order to prevent DFUs and other diabetes complications in patients with T2D

Nucleation of dislocations and their dynamics in layered oxide cathode materials during battery charging

Defects and their interactions in crystalline solids often underpin material properties and functionality as they are decisive for stability, result in enhanced diffusion, and act as a reservoir of vacancies. Recently, lithium-rich layered oxides have emerged among the leading candidates for the next-generation energy storage cathode material, delivering 50 % excess capacity over commercially used compounds. Oxygen-redox reactions are believed to be responsible for the excess capacity, however, voltage fading has prevented commercialization of these new materials. Despite extensive research the understanding of the mechanisms underpinning oxygen-redox reactions and voltage fade remain incomplete. Here, using operando three-dimensional Bragg coherent diffractive imaging, we directly observe nucleation of a mobile dislocation network in nanoparticles of lithium-rich layered oxide material. Surprisingly, we find that dislocations form more readily in the lithium-rich layered oxide material as compared with a conventional layered oxide material, suggesting a link between the defects and the anomalously high capacity in lithium-rich layered oxides. The formation of a network of partial dislocations dramatically alters the local lithium environment and contributes to the voltage fade. Based on our findings we design and demonstrate a method to recover the original high voltage functionality. Our findings reveal that the voltage fade in lithium-rich layered oxides is reversible and call for new paradigms for improved design of oxygen-redox active materials