87 research outputs found

    Effects of Insecticides on Pest Populations and Their Natural Enemies in Soybean Field

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    In the 5-time field experiments and broad demonstrations, effects of volume and application formulae of several pesticides on the population densities of major inset pests and natural enemies in the soybean field were determined. Results from the Ducan’s multiple range test indicated that 300 g/ha of Omethoate (fine granule) and 45 g/ha of Fenvalerate in the seedling stage and 300 g/ha of Chloromethiuron suspensoid in the flowering stage may control pests and protect major natural enemies. Application of these pesticides in the corresponding soybean stages is an effective way that mediates the conflict between chemical and biological controls in the field. There are over 170 species of natural enemies whose hosts are known in the soybean field in China. These natural enemies play important roles in controlling the soybean pests. However, farmers still strongly rely on chemicals to control these pests because natural enemies are not able to timely curb the pest infestations when there is a pest outbreak. Frequent chemical application in a higher volume will ruin the ecological balance. The conflict between biological and chemical controls has become a hot issue in the soybean production worldwide. Our objectives in this study are to decide the effective low concentrations of commonly used pesticides, determine the effect of the third and fourth generations of pesticides on the major insect pests and natural enemies in the soybean field and propose feasible control methods by coordinating control and chemical controls.Originating text in Chinese.Citation: Qi, Yaoxun, Ma, Zhengquan, Shan, De'An, Gao, Xiaohua, Wang, Qisheng. (1987). Effects of Insecticides on Pest Populations and Their Natural Enemies in Soybean Field. Plant Protection (Institute of Plant Protection, CAAS, China), 13, 4-6

    Structure health monitoring of composites joint reinforced by acoustic emission based smart composite fasteners

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    This paper proposed an Acoustic Emission (AE) based Smart Composite Fastener (SCF) concept for health monitoring of bonded/bolted composite single lap joints. The SCF was made of 3D-printed continuous carbon fibre reinforced thermoplastic materials with an embedded piezoelectric sensor. The SCF detected signals were found to be successfully associated with AE damage sources during the loading period. It was discovered that the adhesive crack/delamination AE sources resulted in burst-type signals with identifiable onset and end, whereas AE sources of frictional sliding between the SCF and fastener holes resulted in continuous-type signals producing broad frequency content. Furthermore, the amplitudes of the burst-type signal measured from the network of SCFs were successfully correlated with the locations of the damages. In the direction away from the damage, the amplitudes of the burst-type voltages measured from the SCF showed a decreasing trend, with 10195mv, 9,995mv, and 7,426mv respectively. Generally, the research in this paper explores the correlation between the voltage signal from a damaged AE source and the SCF, providing the feasibility of using a novel SCF for health monitoring in composite joint structures

    A Multi-Branch Multi-Scale Deep Learning Image Fusion Algorithm Based on DenseNet

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    Infrared images have good anti-environmental interference ability and can capture hot target information well, but their pictures lack rich detailed texture information and poor contrast. Visible image has clear and detailed texture information, but their imaging process depends more on the environment, and the quality of the environment determines the quality of the visible image. This paper presents an infrared image and visual image fusion algorithm based on deep learning. Two identical feature extractors are used to extract the features of visible and infrared images of different scales, fuse these features through specific fusion methods, and restore the features of visible and infrared images to the pictures through the feature restorer to make up for the deficiencies in the various photos of infrared and visible images. This paper tests infrared visual images, multi-focus images, and other data sets. The traditional image fusion algorithm is compared several with the current advanced image fusion algorithm. The experimental results show that the image fusion method proposed in this paper can keep more feature information of the source image in the fused image, and achieve excellent results in some image evaluation indexes

    Design and Construction Method of High-low Span Cross Support System for Frame Structures

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    Taking a high-rise frame-shear wall structure project in Jilin Province as an example, combined with current specifications, standards, and regulations, this paper proposes the design and construction method of the scaffold support system for the high-low span and high formwork between the basement and the main structure;In the construction, the side formwork of the high-low span beam adopts the method of suspending formwork, and the combination of fixing support and drawing bolts on both sides. The floor slab is poured first, followed by the high-low span, and the pouring is carried out in layers and sections, ensuring the quality of the project and shortening the construction period. After construction verification, the various acceptance values are better than the current engineering acceptance evaluation standard values, and it is safe and reliable. This provides a reference for the design and construction of similar high-low span and high-formwork projects in frame structures

    Lipid accumulation mechanism of Amphora coffeaeformis under nitrogen deprivation and its application as a feed additive in Carassius auratus aquaculture

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    Abstract Background Amphora coffeaeformis, a unicellular diatom, can significantly accumulate lipids under nitrogen (N) limitation. However, the molecular mechanism underlying lipid accumulation in A. coffeaeformis remains unknown and its application development is lagging. Results This work analyzed the lipid composition of A. coffeaeformis under N deprivation and investigated its mechanism underlying lipid accumulation using RNA-seq. The results showed that the total lipid content of A. coffeaeformis increased from 28.22 to 44.05% after 5 days of N deprivation, while the neutral lipid triacylglycerol (TAG) content increased from 10.41 to 25.21%. The transcriptional profile showed that N deprivation induced wide-ranging reprogramming of regulation and that most physiological activities were repressed, while the upregulation of glycerol-3-phosphate acyltransferase directly determined TAG accumulation. Moreover, we explored the effect of A. coffeaeformis as a food additive on the lipid composition of crucian carp. The results showed that the contents of unsaturated fatty acids in the meat of fish supplemented with A. coffeaeformis were significantly increased, indicating its potential application in animal nutrition for improving meat quality indicators. Conclusion The findings shed light on the molecular mechanisms of neutral lipid accumulation and revealed the key genes involved in lipid metabolism in A. coffeaeformis. Moreover, we also confirmed that A. coffeaeformis can be used as feed additive for improving the lipid composition of crucian carp meat, which provided evidence for the biotechnology application of this high-oil microalgae

    Identification of microRNAs involved in astaxanthin accumulation responding to high light and high sodium acetate (NaAC) stresses in Haematococcus pluvialis

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    The growth and astaxanthin production of unicellular Haematococcus pluvialis is affected by both the high light and sodium acetate (NaAC) stresses. There are sparse on studies of the regulatory pathways of microRNAs (miRNAs) and their target genes in response to high light and NaAC stresses in H. pluvialis. In this study, transcriptomic analysis was used to identify the key target genes of miRNA regulation under both high light and NaAC stresses. A total of 434 (including 29 novel) miRNAs were identified, which were mainly enriched in metal ion binding and transport, and involved in basic metabolic pathways, such as pyruvate metabolism, ubiquitin mediated proteolysis, and oxidative phosphorylation. A total of 115 (out of 434) miRNAs were detected in response to high light and NaAC stresses. A total of 83 and 46 miRNAs significantly expressed under high light and NaAC stresses were considered as high light and NaAC stress responsive miRNAs, respectively. 14 miRNAs responded to both high light and NaAC stresses. Some miRNAs that regulate differentially expressed target genes had been identified. In the high light treatment group, 38 regulatory pairs were identified. In NaAc treatment group, 40 regulatory pairs were identified. These results shed light on the regulatory mechanisms of miRNAs responding to high light and NaAC stresses in H. pluvialis, further providing support for understanding the molecular mechanisms of miRNA regulation involved in astaxanthin synthesis in H. pluvialis

    Water-Soluble Chitosan Nanoparticles Inhibit Hypercholesterolemia Induced by Feeding a High-Fat Diet in Male Sprague-Dawley Rats

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    Chitosan, a deacetylated product of chitin, has been demonstrated to lower cholesterol in humans and animals. However, chitosan is not fully soluble in water which would influence absorption in the human intestine. In addition, water-soluble chitosan (WSC) has higher reactivity compared to chitosan. The present study was designed to clarify the effects of WSC and water-soluble chitosan nanoparticles (WSC-NPs) on hypercholesterolemia induced by feeding a high-fat diet in male Sprague-Dawley rats. WSC-NPs were prepared by the ionic gelation method and the spray-drying technique. The nanoparticles were spherical in shape and had a smooth surface. The mean size of WSC-NPs was 650 nm variing from 500 to 800 nm. Results showed that WSC-NPs reduced the blood lipids and plasma viscosity significantly and increased the serum superoxide dismutase (SOD) activities significantly. This paper is the first report of the lipid-lowering effects of WSC-NPs suggesting that the WSC-NPs could be used for the treatment of hypercholesterolemia
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