FGL-GAN: Global-Local Mask Generative Adversarial Network for Flame Image Composition.

It is important to reduce the danger of collecting flame image data sets by compositing flame images by computer. In this paper, a Global-Local mask Generative Adversarial Network (FGL-GAN) is proposed to address the current status of low quality composite flame images. First, FGL-GAN adopts a hierarchical Global-Local generator structure, to locally render high-quality flame halo and reflection, while also maintaining a consistent global style. Second, FGL-GAN incorporates the fire mask as part of the input of the generation module, which improves the rendering quality of flame halo and reflection. A new data augmentation technique for flame image compositing is used in the network training process to reconstruct the background and reduce the influence of distractors on the network. Finally, FGL-GAN introduces the idea of contrastive learning to speed up network fitting and reduce blurriness in composite images. Comparative experiments show that the images composited by FGL-GAN have achieved better performance in qualitative and quantitative evaluation than mainstream GAN. Ablation study shows the effectiveness of the hierarchical Global-Local generator structure, fire mask, data augmentation, and MONCE loss of FGL-GAN. Therefore, a large number of new flame images can be composited by FGL-GAN, which can provide extensive test data for fire detection equipment, based on deep learning algorithms.

Soybean inclusion reduces soil organic matter mineralization despite increasing its temperature sensitivity.

Legume-based cropping increased the diversity of residues and rhizodeposition input into the soil, thus affecting soil organic matter (SOM) stabilization. Despite this, a comprehensive understanding of the mechanisms governing SOM mineralization and its temperature sensitivity across bulk soil and aggregate scales concerning legume inclusion remains incomplete. Here, a 6-year field experiment was conducted to investigate the effects of three cropping systems (i.e., winter wheat/summer maize, winter wheat/summer maize-soybean, and nature fallow) on SOM mineralization, its temperature sensitivity, and the main drivers in both topsoil (0-20 cm) and subsoil (20-40 cm). Soybean inclusion decreased the SOM mineralization by 17%-24%, while concurrently increasing the majority of soil biochemical properties, such as carbon (C) acquisition enzyme activities (5%-22%) and microbial biomass C (5%-9%), within the topsoil regardless of temperature. This is attributed to the increased substrate availability (e.g., dissolved organic C) facilitating microbial utilization, thus devoting less energy to mining nutrients under diversified cropping. In addition, SOM mineralization was lower within macroaggregates (∼12%), largely driven by substrate availability irrespective of aggregate sizes. In contrast, diversified cropping amplified the Q10 of SOM mineralization in mesoaggregates (+6%) and microaggregates (+5%) rather than in macroaggregates. This underscores the pivotal role of mesoaggregates and microaggregates in dominating the Q10 of SOM mineralization under soybean-based cropping. In conclusion, legume-based cropping diminishes soil organic matter mineralization despite increasing its temperature sensitivity, which proposes a potential strategy for C-neutral agriculture and climate warming mitigation.

Diversified cropping systems benefit soil carbon and nitrogen stocks by increasing aggregate stability: Results of three fractionation methods.

Understanding carbon (C) and nitrogen (N) sequestration in diversified cropping systems provides a pivotal insight for soil health management. Here, the soil was sampled from an ongoing field experiment (five years) with three cropping systems: i) winter wheat/summer maize, ii) winter wheat/summer maize-early soybean, and iii) fallow. We evaluated C and N stocks in aggregates for topsoil (0-20 cm) and subsoil (20-40 cm) depending on cropping systems by comparison of three aggregate fractionation methods (dry, optimal-moisture, and wet sieving). Although the fertilizer application rate for wheat/maize was twice as much as for wheat/maize-soybean, this resulted in similar C and N stocks in the topsoil. The N stock, however, was 13% higher under wheat/maize-soybean than under wheat/maize in the subsoil due to N2 fixation by soybean. The C and N stocks decreased by 22% and 12% under fallow compared to wheat/maize in the topsoil. The wheat/maize-soybean cropping system increased soil aggregates size when estimated by dry and optimal-moisture fractionations. The aggregate size distribution shifted from the dominance of large (> 2 mm) toward small macroaggregates (0.25-2 mm) with increasing moisture used by fractionation due to the low stability of large macroaggregates. Thus, the combination of dry and optimal-moisture sieving is the preferred method to characterize aggregate stability. Overall, diversified cropping systems increase soil aggregation and stability, thus have great potential to enhance soil C and N stocks.

Do cropping system and fertilization rate change water-stable aggregates associated carbon and nitrogen storage?

Soil aggregates not only store carbon (C) and nitrogen (N) but hold a critical role in determining the nutrients supply, crop productivity, and climate change mitigation. However, the impact of cropping system and N fertilization on aggregate-associated C and N in both topsoil and subsoil remains unclear. Here, we assessed the effect of cropping systems (wheat-soybean vs. wheat-maize cropping systems) and N fertilization rates (0 N; medium N, 120 kg N ha-1; high N, 240 kg N ha-1) on soil water-stable aggregates distribution, as well as aggregate-associated C and N based on a field study in North China Plain. Our study suggests that the variations of soil organic carbon (SOC) and total nitrogen (TN) stocks were more affected by N fertilization than short-term cropping systems. In the wheat-soybean system, medium N increased the SOC stock by 19.18% and 15.73% as compared to high N in the topsoil and subsoil, respectively. Additionally, medium N resulted in 6.59-18.11% higher TN stock in the topsoil for both wheat-soybean and wheat-maize cropping systems as compared to 0 N and high N. Notably, the water-stable macroaggregates (> 0.25 mm) in the topsoil occupied more than 70% of the soil, which increased under medium N in the wheat-soybean cropping system. In conclusion, medium N fertilization combined with a legume-based cropping could be used to improve SOC stock, promote soil aggregation, and enhance aggregate-associated C.

Palladium-catalyzed cross-coupling of stereospecific potassium cyclopropyl trifluoroborates with aryl bromides.

[reaction: see text] Stereospecific cyclopropanation of alkenylboronic esters of pinacol followed by in situ treatment with excess KHF(2) afforded the corresponding potassium cyclopropyl trifluoroborates in high yields, which then underwent Suzuki-Miyaura cross-coupling reactions with aryl bromides to give cyclopropyl-substituted arenes in good yields with retention of configuration. This promises to be a useful method for the synthesis of enantiomerically pure cyclopropanes.