The aim of this study was to optimize the extraction process of total flavonoids from Annona squamosa leaves and study their antioxidant activity in vitro. Using ethanol as extraction solvent, the response surface methodology was used to optimize the extraction process of total flavonoids from lychee leaves based on the results of single factor experiments. DPPH,-OH and ABTS were used as indicators to comprehensively evaluate the in vitro antioxidant activity of total flavonoids from lychee leaves. The results showed that the optimal extraction parameters were: Ethanol volume fraction 70%, liquid to material ratio 50∶1(mL: g), ultrasonic time 85 minutes, ultrasonic temperature 67 ℃. The extraction rate of total flavonoids was 4.37% under this process. The antioxidant activity of total flavonoids was evaluated by three indexes(the scavenging ability of DPPH,-OH and ABTS). The results showed that total flavonoids from Annona squamosa leaves had good scavenging effects on DPPH,-OH and ABTS, with the IC50 values were 94.78 μg/mL, 756.34 μg/mL and 419.91 μg/mL, respectively. And the scavenging effect on -OH was stronger than that of VC. The process determined in this study was simple and feasible. The total flavonoids extracted from Annona squamosa leaves had high extraction rate and strong antioxidant capacity.

In order to further develop and utilize Artabotrys plants in Annonaceae and provide reference for the screening and application of natural antioxidants in medicines or foods, four Artabotrys species(Artabotrys hainanensis, Artabotrys hexapetalus, Artabotrys pilosus, Artabotrys pachypetalus) were selected as research objects in this study. The contents of total polyphenols and total flavonoids of the ethanol extracts of the leaves were determined. The antioxidative activities of four Artabotrys species were evaluated by using the scavenging ability of DPPH·, ·OH and ABTS· as three indicators. The results are as follows: (1) The contents of the total polyphenols and the total flavonoids in the leaf extracts of the four species are significantly different. The contents of total flavonoids of the four species range from 1.33 to 7.99 mg/g, and the contents of the total polyphenols of the four species range from 2.26 to 9.50 mg/g. Among the four species, A. pilosus has the highest contents of total polyphenols and total flavonoids. (2) The four extraxts all have antioxidant activity, and the antioxidant activity increases with the increase of the concentration of the leaf extracts. Among the four species, the leaf extracts of A. pilosus has the strongest radical scavenging capacity on DPPH·, ABTS+· and also has good ability to scavenge ·OH radicals. (3) The total flavonoids contents and the scavenging ability of DPPH· and ABTS+· are positive correlated, and the total polyphenol contents and the scavenging ability of DPPH· and ABTS+· are significantly positive correlated. In general, the leaf extracts of A. pilosus has the best antioxidant activity among the four Artabotrys species and has the potential to be developed as a natural antioxidant.

The effects of N, P and K fertilizer application on the growth and nutrient absorption of Pennisetum hydridum were discussed when using dredged soil as the planting substrate, and the most suitable fertilizer ratio was screened out, the fertilizer demand law of Pennisetum hydridum was revealed, and the theoretical basis was provided for the efficient cultivation of Pennisetum hydridum on dredged soil, scientific and reasonable disposal and reclamation of Dredging soil.The dredged soil was used as the test soil and Pennisetum hydridum was used as the planting material to carry out the potting test. Three factors of N, P and K were set up at three levels for each factor. Growth indicators such as plant height, leaf number, dry weight and nutrient absorption of the whole plant were measured under different fertilization treatments. The results showed that formula fertilization could significantly increase the plant height, biomass and N, P and K nutrient uptake(P<0.05). The plant height, leaf number, total biomass, N, P and K uptake of the whole plant increased by 59.87%, 68.39%, 378.46%, 455.54%, 433.79% and 454.37% respectively compared with CK under S4 treatment(1.41 g N, 0.83 g P2O5 and 0.5 g K2O per plant). The comprehensive evaluation results of different fertilization treatment effects showed that S4(N2P1K2) was the most ideal fertilization formula, which could significantly promote the growth and nutrient absorption of Pennisetum hydridum, and promote the growth of Pennisetum hydridum in the dredged soil. Reasonable combined application of N, P and K can increase the biomass and nutrient absorption of Pennisetum hydridum, and promote the growth of Pennisetum hydridum in dredged soil.

Ancient tree resource is a category of forest genetic resources that garner significant interest due to their substantial historical, cultural, and scientific research value. This study conducted a comprehensive survey of the extant ancient tree resources within the Xingning Basin in Guangdong, and found that a total of 364 individual trees existed with the majority being classified as third-grade ancient trees, comprising 94.23% of the total. These ancient trees are distributed across 26 families, 33 genera, and 38 species, with a dominance of the Altingiaceae and Moraceae families. The predominant species include Ficusconcinna(Miq.) Miq.,Altingiagracilipes Hemsl., Castanopsishystrix Hook. f. & Thomson ex A. DC., Celtissinensis Pers., and Liquidambar formosana Hance. The ancient trees in the Xingning Basin demonstrate distinctive spatial distribution characteristics and high biodiversity, with a spatial kernel density of 0.172 trees/km and an altitudinal distribution ranging from 98 to 529 meters. According to the natural breakpoint method, the elevation zone from 92 to 278 meters has the richest ancient tree resources, with a total of 279 trees accounting for 76.65% of the overall count. Geographically, the northern and eastern sections of the basin, namely Luofu Town and Jingnan Town, exhibit the highest distribution densities, with 56 trees (15.38%) and 40 trees (10.99%) respectively, and a kernel density between 0.55 to 0.67 trees/km2. However, the overall growth condition of the ancient trees is deemed moderate, with 67.31% in a normal growth state, while 32.69% are in a weakened or endangered condition. It is thus essential to implement appropriate conservation and restoration measures for these weakened or endangered ancient trees to maintain their ecological value and biodiversity.

The output synchronization was investigated for a kind of time-varying complex dynamical networks with uncertain nonlinear functions and different dimensional nodes by the method of decentralized output feedback control. The inevitable uncertain nonlinear function in each node was considered into our network model, which is different from other network models in the existing literature on the output synchronization. Besides, in our network model, the outer coupling matrix was allowed to be time-varying, non-zero row sum, uncertain and asymmetric. Thus, the network model can better describe the actual networks. The definition of the asymptotic output synchronization was introduced for our network. In addition, to realize the output synchronization of our network, a decentralized output feedback control strategy was proposed and the correctness of the strategy was strictly proved by the Lyapunov stability theory and Barbalat's lemma. Finally, the effectiveness of the theoretical result was verified by numerical simulations.

A general shape-adjustable cubic trigonometric Hermit interpolation spline is constructed, which can accurately represent engineering curve arcs of ellipse, parabola, cubic parabola and asteroid. By changing parameters in basis, the curve shape can be easily adjusted according to the needs. The interpolated error was studied. Numerical examples and conclusions were given.

Based on the import and export data of tilapia products from 2012 to 2021, this study uses competitiveness indicators to analyze the international competitiveness of tilapia products in Guangdong Province and whether they have export advantages. By comparing with other major tilapia exporting provinces in China, the advantages and disadvantages of tilapia product export trade in Guangdong Province were explored. The results show that the international competitiveness of tilapia in Guangdong Province reached its highest level from 2016 to 2017, then declined. Fresh or cold tilapias have a strong export competitive advantage when compared to other provinces. The export competitiveness of frozen tilapia was basically the same as that of Hainan Province, but was weaker than that of Fujian Province. The export competitiveness of frozen tilapia and catfish in Guangdong Province was relatively weak, and the international competitiveness was not as strong as that of Hainan Province. Based on the research analysis, the following countermeasures and suggestions are proposed: export structure should be adjusted to open up domestic and international circulation channels; It's necessary to establish a full process monitoring system to ensure the quality and safety of fish fry, and scientifically plan tilapia culture plans in conjunction with intelligent agriculture. By implementing a diversified export market strategy, explore pre-made products of tilapia, optimize product structure, thus to enhance international competitiveness.

Loop-mediated isothermal amplification(LAMP) is a new nucleic acid amplification method with the advantage of high specificity and sensitivity, convenient operation, offering a favorable technical approach for the rapid detection of plant diseases. This technique has been widely applied to the detection of various pathogens including fungi, bacteria, viruses, and nematodes. This article provides an overview of the basic principles and development status of LAMP technology, and summarizes the LAMP application in the detection of plant pathogens, offering a reference for future research and application of LAMP technology in pathogen detection and early diagnosis.

Human behavior recognition, as an important research hotspot in the field of computer vision, has received much attention in recent years and has broad application prospects in various fields such as smart healthcare, smart agriculture, monitoring and security. With the development of deep learning technology, its application in human behavior recognition has become a trend. Compared to traditional human behavior recognition methods, deep learning based human behavior recognition methods has advantages such as strong adaptability high robustness, fast speed, and higher accuracy, resulting in better recognition results. The article provides a brief introduction to the human behavior recognition method based on manually extracted features, and then sorts out and analyzes deep learning based methods from the perspective of network structure, with a focuse on deep learning network frameworks such as 3D convolutional neural network, dual flow network, recurrent neural network, Transformer, etc. The commonly used datasets in this field, performance of some algorithms on datasets UCF-101 and HMDB-51, were also analyzed and compared. Finally, the current research in this field were summarized and prospected.

Community support agriculture(CSA) is a new form of ecological agriculture and an effective way to solve food safety problems, CSA emphasizes organic and environmentally friendly farming methods, and is a localized production and consumption mode with producers and consumers as the core. As an emerging agricultural production mode, CSA is developing rapidly in China, but some prominent problems appear objectively. This paper sorted out the relevant literature of CSA in detail based on the background, connotation, developmental status, existing problems and countermeasures of CSA. By deeply understanding the research progress of CSA, the current study help to promote the development of CSA.