Productivity model and experiment of field crop spraying by plant protection unmanned aircraft

Traditional agricultural production requires numerous human and material resources; however, agricultural production efficiency is low. The successful development of plant protection unmanned aerial vehicles (UAVs) has changed the operation mode of traditional agricultural production, saving human, material, and financial resources and significantly improving production efficiency. To summarize the process of improving the productivity of plant protection UAVs, this study established a productivity calculation model of UAVs based on the time composition of the UAV agricultural plant protection process, including spraying, turning, replenishment, and transfer times. The time required for the unmanned aircraft application process was counted through years of tracking the application process of eight different plant protection unmanned aircraft. Plot lengths of 100, 300, 500, 700, 1,000, 1,500, 2,000, 2,500, 3,000, and 3,500 m were established to calculate the theoretical productivity. The results showed that the productivity of different types of plant protection UAVs increased with an increase in plot length in the range of 100 to 1,500 m; however, when the plot length reached a certain value, the productivity growth rate slowed down or even decreased slightly. Simultaneously, based on the working area per 10,000 mu, the recommended plot length and the number of configured models for different models were recommended. If the plant protection UAV was distinguished by electric and oil power, the time utilization rate of electric plant protection UAVs was 72.7%, and the labor productivity was 56.4 mu/person·h. In contrast, the time utilization rate of the heavy load oil-powered plant protection unmanned aircraft was 86%, and the labor productivity was 63.5 mu/person ·h. This study can support plant protection UAV enterprises to optimize equipment efficiency, provide evaluation methods for the operation efficiency assessment of plant protection UAVs, provide a reference for the selection of plant protection UAVs, and provide a basis for field planning

A New Species of Gracixalus (Anura: Rhacophoridae) from West Guangxi, China

We discovered a new species of the genus Gracixalus, Gracixalus tianlinensis sp. nov. which is morphologically almost similar to G. jinggangensis, G. jinxiuensis and G. sapaensis, but is distinguished from these species and all other rhacophorids in China and adjoining countries by a combination of the following characters: (1) SVL 30.3-35.9 mm in male, 35.6-38.7 mm in female, (2) head length less than head width, (3) vomerine teeth absent, (4) supratympanic fold distinct, (5) axilla and posterior surface of flanks pale yellow, (6) nuptial pads distinct on Finger I and slightly visible on Finger II, (7) dorsum brown to beige, with an inverse Y-shaped dark brown marking, (8) single subgular vocal sac. Our preliminary phylogenetic analyses implied G. tianlinensis sp. nov. is sister to G. sapaensis with well-supported values. Currently, this new species is known to be distributed in montane evergreen forests in association with montane bamboo in Cenwanglaoshan National Nature Reserve, Tianlin County, Guangxi, China

Effects of lotus anthocyanins on the quality of ice cream

Recently, more and more attentions are payed to improve the quality and safety of food during processing and storage, and food additives are screened as the good solution plan according to various practices in a long history. Although some synthetic additives are effective, their potential toxicity and hazards on human health are being considered. Thus, the natural additives from food and other natural sources may be the alternative approach. In present study, the modification of lotus anthocyanins on the quality of ice cream was investigated. With the addition of lotus anthocyanins, the color of ice cream changed to purple, and its a* value increased and L* and b* values decreased, which enhanced its attractiveness to consumers. Meanwhile, in the low range of addition amount (0.5% to 1.5%, m/m), lotus anthocyanins increased the expansion rate of ice cream and decreased its melting rate, which was beneficial for air filling and delaying its melting. In addition, lotus anthocyanins at low amount (0.5% to 1.5%, m/m) could ameliorated the texture, rheology and interface properties of ice cream, and further changed the particle size distribution of ice cream to a appropriate range, so as to enhance the stability and shelf life of ice cream. All present results suggest that lotus anthocyanins at the appropriate amount can improve the quality of ice cream, and have the potential applications on ice cream production in food industry

PVO: Panoptic Visual Odometry

We present PVO, a novel panoptic visual odometry framework to achieve more comprehensive modeling of the scene motion, geometry, and panoptic segmentation information. Our PVO models visual odometry (VO) and video panoptic segmentation (VPS) in a unified view, which makes the two tasks mutually beneficial. Specifically, we introduce a panoptic update module into the VO Module with the guidance of image panoptic segmentation. This Panoptic-Enhanced VO Module can alleviate the impact of dynamic objects in the camera pose estimation with a panoptic-aware dynamic mask. On the other hand, the VO-Enhanced VPS Module also improves the segmentation accuracy by fusing the panoptic segmentation result of the current frame on the fly to the adjacent frames, using geometric information such as camera pose, depth, and optical flow obtained from the VO Module. These two modules contribute to each other through recurrent iterative optimization. Extensive experiments demonstrate that PVO outperforms state-of-the-art methods in both visual odometry and video panoptic segmentation tasks.Comment: CVPR2023 Project page: https://zju3dv.github.io/pvo/ code: https://github.com/zju3dv/PV

Comparative Analysis of Complete Chloroplast Genomes of Nine Species of Litsea (Lauraceae): Hypervariable Regions, Positive Selection, and Phylogenetic Relationships

Litsea is a group of evergreen trees or shrubs in the laurel family, Lauraceae. Species of the genus are widely used for a wide range of medicinal and industrial aspects. At present, most studies related to the gene resources of Litsea are restricted to morphological analyses or features of individual genomes, and currently available studies of select molecular markers are insufficient. In this study, we assembled and annotated the complete chloroplast genomes of nine species in Litsea, carried out a series of comparative analyses, and reconstructed phylogenetic relationships within the genus. The genome length ranged from 152,051 to 152,747 bp and a total of 128 genes were identified. High consistency patterns of codon bias, repeats, divergent analysis, single nucleotide polymorphisms (SNP) and insertions and deletions (InDels) were discovered across the genus. Variations in gene length and the presence of the pseudogene ycf1Ψ, resulting from IR contraction and expansion, are reported. The hyper-variable gene rpl16 was identified for its exceptionally high Ka/Ks and Pi values, implying that those frequent mutations occurred as a result of positive selection. Phylogenetic relationships were recovered for the genus based on analyses of full chloroplast genomes and protein-coding genes. Overall, both genome sequences and potential molecular markers provided in this study enrich the available genomic resources for species of Litsea. Valuable genomic resources and divergent analysis are also provided for further research of the evolutionary patterns, molecular markers, and deeper phylogenetic relationships of Litsea

Glacial lake evolution and glacier–lake interactions in the Poiqu River basin, central Himalaya, 1964–2017

This study was supported by grants from the Natural Science Foundation of China (41871056, 21661132003, 41571068, 41571061 and 41771088), the Strategic Priority Research Program (A) of the Chinese Academy of Sciences (XDA20060201), the Swiss National Science Foundation (project: “Recent and future EVOlution of Glacial LAkes in China (EVOGLAC)”, IZLCZ2_169979/1) and the Dragon 4 project funded by ESA (4000121469/17/I-NB). G. Zhang thanks the China Scholarship Council for supporting his visit to University of Zurich from December 2017 to December 2018 (no. 201704910339). TanDEM-X CoSSC data were provided by German Aerospace Center (DLR) with proposal ATI_HYDR7290.Despite previous studies, glacier–lake interactions and future lake development in the Poiqu River basin, central Himalaya, are still not well understood. We mapped glacial lakes, glaciers, their frontal positions and ice flow from optical remote sensing data, and calculated glacier surface elevation change from digital terrain models. During 1964–2017, the total glacial-lake area increased by ~110%. Glaciers retreated with an average rate of ~1.4 km2 a−1 between 1975 and 2015. Based on rapid area expansion (>150%), and information from previous studies, eight lakes were considered to be potentially dangerous glacial lakes. Corresponding lake-terminating glaciers showed an overall retreat of 6.0 ± 1.4 to 26.6 ± 1.1 m a−1 and accompanying lake expansion. The regional mean glacier elevation change was −0.39 ± 0.13 m a−1 while the glaciers associated with the eight potentially dangerous lakes lowered by −0.71 ± 0.05 m a−1 from 1974 to 2017. The mean ice flow speed of these glaciers was ~10 m a−1 from 2013 to 2017; about double the mean for the entire study area. Analysis of these data along with climate observations suggests that ice melting and calving processes play the dominant role in driving lake enlargement. Modelling of future lake development shows where new lakes might emerge and existing lakes could expand with projected glacial recession.Publisher PDFPeer reviewe

An improved ion-exchange/diffusion method for N-15 isotope tracing analysis of nitrate in surface waters from watersheds

An improved method, suitable for collecting nitrate from surface waters in the watershed for N-15 isotope tracing analysis, was developed on the basis of the anion exchange coupled with diffusion through systematic simulation and comparison experiments. The results showed that the nitrate could be separated and enriched from the waters efficiently by using the improved method. Being simple and practical in operation principle and procedures, cost-economic, and highly efficient in nitrate separation/enrichment, the method met the requirements of alpha N-15 mass spectrum analysis and would lay a foundation for the application of N-15 isotope tracing approach to the research on non-point source pollution in watershed.Department of Science and Technology of Fujian Province, China [2002H009

Extensive and drastically different alpine lake changes on Asia's high plateaus during the past four decades

Asia's high plateaus are sensitive to climate change and have been experiencing rapid warming over the past few decades. We found 99 new lakes and extensive lake expansion on the Tibetan Plateau during the last four decades, 1970–2013, due to increased precipitation and cryospheric contributions to its water balance. This contrasts with disappearing lakes and drastic shrinkage of lake areas on the adjacent Mongolian Plateau: 208 lakes disappeared, and 75% of the remaining lakes have shrunk. We detected a statistically significant coincidental timing of lake area changes in both plateaus, associated with the climate regime shift that occurred during 1997/1998. This distinct change in 1997/1998 is thought to be driven by large-scale atmospheric circulation changes in response to climate warming. Our findings reveal that these two adjacent plateaus have been changing in opposite directions in response to climate change. These findings shed light on the complex role of the regional climate and water cycles and provide useful information for ecological and water resource planning in these fragile landscapes.Publisher PDFPeer reviewe

Radiomics Signature on Computed Tomography Imaging: Association With Lymph Node Metastasis in Patients With Gastric Cancer

Background: To evaluate whether radiomic feature-based computed tomography (CT) imaging signatures allow prediction of lymph node (LN) metastasis in gastric cancer (GC) and to develop a preoperative nomogram for predicting LN status.Methods: We retrospectively analyzed radiomics features of CT images in 1,689 consecutive patients from three cancer centers. The prediction model was developed in the training cohort and validated in internal and external validation cohorts. Lasso regression model was utilized to select features and build radiomics signature. Multivariable logistic regression analysis was utilized to develop the model. We integrated the radiomics signature, clinical T and N stage, and other independent clinicopathologic variables, and this was presented as a radiomics nomogram. The performance of the nomogram was assessed with calibration, discrimination, and clinical usefulness.Results: The radiomics signature was significantly associated with pathological LN stage in training and validation cohorts. Multivariable logistic analysis found the radiomics signature was an independent predictor of LN metastasis. The nomogram showed good discrimination and calibration.Conclusions: The newly developed radiomic signature was a powerful predictor of LN metastasis and the radiomics nomogram could facilitate the preoperative individualized prediction of LN status