Bridge Model Updating Based on Wavelet Neural Network and Wind-Driven Optimization.

Aging, corrosive environments, and inadequate maintenance may result in performance deterioration of civil infrastructures, and finite element model updating is a commonly employed structural health monitoring procedure in civil engineering to reflect the current situation and to ensure the safety and serviceability of structures. Using the finite element model updating process to obtain the relationship between the structural responses and updating parameters, this paper proposes a method of using the wavelet neural network (WNN) as the surrogate model combined with the wind-driven optimization (WDO) algorithm to update the structural finite element model. The method was applied to finite element model updating of a continuous beam structure of three equal spans to verify its feasibility, the results show that the WNN can reflect the nonlinear relationship between structural responses and the parameters and has an outstanding simulation performance; the WDO has an excellent ability for optimization and can effectively improve the efficiency of model updating. Finally, the method was applied to update a real bridge model, and the results show that the finite element model update based on WDO and WNN is applicable to the updating of a multi-parameter bridge model, which has practical significance in engineering and high efficiency in finite element model updating. The differences between the updated values and measured values are all within the range of 5%, while the maximum difference was reduced from -10.9% to -3.6%. The proposed finite element model updating method is applicable and practical for multi-parameter bridge model updating and has the advantages of high updating efficiency, reliability, and practical significance.

Lumped Plasticity Model and Hysteretic Performance of Ultra-High-Performance Concrete Rocking Pier.

Rocking piers using ultra-high-performance concrete (UHPC) have high damage-control capacity and self-centering characteristics that can limit the post-earthquake recovery time of bridges. To study the hysteretic behavior of UHPC rocking piers, a lumped plasticity model is proposed that comprises two parallel rotational springs and which can accurately calculate their force-displacement hysteretic behavior. Three states of the rocking piers, decompression, yield, and large deformation, are considered in this study. The model is verified based on existing experimental results, and the hysteretic characteristics of the UHPC rocking piers, such as strength, stiffness, and energy dissipation, are further analyzed. The research results show that the lumped plasticity analysis model proposed in this study can predict the force-displacement hysteretic behavior of the rocking piers accurately. Moreover, the hysteretic performance of the UHPC rocking piers is better than that of rocking piers using normal-strength concrete. An increase in the energy dissipation reinforcement ratio, pre-stressed tendon ratio, and initial pre-stress improves the lateral stiffness and strength of the UHPC rocking piers. However, the increase in the pre-stressed tendon ratio and initial pre-stress reduces their energy-dissipation capacity.

A plant virus enhances odorant-binding protein 5 (OBP5) in the vector whitefly for more actively olfactory orientation to the host plant.

BACKGROUND: The whitefly Bemisia tabaci (Hemiptera: Aleyrodidae) is a notorious agricultural pest and the effective vector of many plant viruses worldwide. Cucurbit chlorotic yellows virus (CCYV), exclusively transmitted by B. tabaci in a semipersistent manner, is a serious causal agent in cucurbit crops in many countries. Plant viruses can manipulate the behaviors of insect vectors to promote the spread of themselves, but underlying mechanisms are remaining unclear. RESULTS: In this study, our observations indicated that B. tabaci, when carrying CCYV, oriented more actively to the host plant cucumber. Transcriptome analysis and quantitative polymerase chain reaction with reverse transcription analysis showed that the odorant-binding protein 5 (OBP5) was upregulated with viral acquisition. Sequence and phylogenetic analysis showed that BtabOBP5 was highly homologous with nine OBPs from other hemipteran insects. In addition, OBP5-silenced whiteflies significantly altered their orientation behavior towards cucumber plants and towards some typical volatile organic compounds released from cucumbers. CONCLUSION: This study described a novel mechanism by which the olfactory system of vector insects could be regulated by a semipersistent plant virus, thereby affecting insect olfactory behavior and relationship with host plants. These results provided a basis for developing potential olfaction-based pest management strategies in the future. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Discovery of novel whitefly vector proteins that interact with a virus capsid component mediating virion retention and transmission.

Specificity and efficiency of plant virus transmission depend largely on protein-protein interactions of vectors and viruses. Cucurbit chlorotic yellows virus (CCYV), transmitted specifically by tobacco whitefly, Bemisia tabaci, in a semi-persistent manner, has caused serious damage on cucurbit and vegetable crops around the world. However, the molecular mechanism of interaction during CCYV retention and transmission are still lacking. CCYV was proven to bind particularly to the whitefly foregut, and here, we confirmed that the minor coat protein (CPm) of CCYV is participated in the interaction with the vector. In order to identify proteins of B. tabaci that interact directly with CPm of CCYV, the immunoprecipitation (IP) assay and DUALmembrane cDNA library screening technology were applied. The cytochrome c oxidase subunit 5A (COX), tubulin beta chain (TUB) and keratin, type I cytoskeletal 9-like (KRT) of B. tabaci shown strong interactions with CPm and are closely associated with the retention within the vector and transmission of CCYV. These findings on whitefly protein-CCYV CPm interactions are crucial for a much better understanding the mechanism of semi-persistent plant virus transmission by insect vectors, as well as for implement new strategies for effective management of plant viruses and their vector insects.

Widely targeted analysis of metabolomic changes of Cucumis sativus induced by cucurbit chlorotic yellows virus.

BACKGROUND: Plant metabolites play vital roles in regulating the behavior of herbivore insects. Virus infection can universally alter plant metabolites to manipulate the orientation and feeding behaviors of insect vector, to favor the transmission of virus. Thus, determining the differentially accumulated metabolites of plant upon virus infection could provide insights into understanding how the triple interactions among plant, virus and insect vector happens. Our previous studies have found that vector whitefly Bemisia tabaci (Gennadius, Hemiptera: Aleyrodidae) showed different orientation behavior and performance on CCYV-infected and healthy cucumber plants. Cucurbit chlorotic yellows virus (CCYV) is exclusively transmitted by B. tabaci in a semi-persistent mode. In this study, we take the CCYV, B. tabaci and cucumber as a research system to explore the functions of phyto-metabolites in the triple interactions. RESULTS: A total of 612 metabolites changed upon CCYV infection were monitored. Metabolites mainly enriched in flavonoids, lipids, nucleotides and their derivatives. At 7 days post CCYV inoculation (dpi), the contents of lipids, terpenoids and flavonoids remarkably decreased, while amino acids, nucleotides and their derivatives notably up-accumulated. At 15 dpi, the accumulation of flavonoids were still significantly reduced upon CCYV infection, while lipids, amino acids, nucleotides and derivatives were remarkably enhanced. Most of significantly increased metabolites were lipids (lysophosphatidylethanolamine, LPE; lysophosphatidylcholine, LPC and their isomers). Also, the number of significantly changed metabolites increased with the infection period. However, only a few organic acids and phenolic acids showed difference between CCYV-infected and healthy cucumber plants. CONCLUSIONS: CCYV infection repressed the defensive flavonoids, terpeneoids metabolism but triggered the lipids, amino acids and nucleotides metabolism with the inoculation period. This result suggests that CCYV-infection makes cucumber plants more susceptible for whiteflies attack and CCYV infection. The reduction of defensive comounds and the increase of amino acids may be partially responsible for enhancing feeding preference of whiteflies to CCYV-infected hosts. CCYV may hijacked lipid metabolism for virus replication and assembly.

Geochemical and Statistical Analyses of Trace Elements in Lake Sediments from Qaidam Basin, Qinghai-Tibet Plateau: Distribution Characteristics and Source Apportionment.

The safety of lake ecosystems on the Qinghai-Tibet Plateau (QTP) has attracted increasing attention, owing to its unique location and ecological vulnerability. Previous studies have shown that the aquatic systems on the QTP have been polluted to varying degrees by trace elements. However, little is known of the distribution and sources of trace elements in lakes in the northeast QTP. Here, 57 sediment samples were collected from six lakes (Dasugan Lake, Xiaoqaidam Lake, Kreuk Lake, Toson Lake, Gahai Lake and Xiligou Lake) in the Qaidam Basin, northeast QTP, and the trace elements (V, Cr, Ni, Cu, Zn, As, Ba, Tl, Cd, Pb, and U) were analyzed. The results indicated that Ba, Zn, V, and Cr had a higher content and a wider distribution relative to the other tested elements. Correlation coefficient matrix results showed that the trace elements in the study area were strongly correlated, revealing their source of similarity. Self-organizing maps (SOM, an artificial neural network algorithm) results indicated that the degree of pollution in Xiaoqaidam Lake was the highest, and that of Dasugan Lake was the lowest. Furthermore, all sampling points were clustered into four categories through K-means clustering. The positive matrix factorization (PMF) results indicated that atmospheric deposition and anthropogenic inputs were the main trace elements sources in these lakes, followed by traffic emission and geological sources. Collectively, trace elements of six lakes in Qinghai-Tibet Plateau presented high-content and pollution characteristics. This research provides a scientific basis for better water environment management and ecological protection on the QTP.

Impacts of Cucurbit Chlorotic Yellows Virus (CCYV) on Biological Characteristics of Its Vector Bemisia tabaci (Hemiptera: Aleyrodidae) MED Species.

Plant viruses can change the phenotypes and defense pathways of the host plants and the performance of their vectors to facilitate their transmission. Cucurbit chlorotic yellows virus (CCYV) (Crinivirus), a newly reported virus occurring on cucurbit plants and many other plant species, is transmitted specifically by Bemisia tabaci MEAM1 (B biotype) and MED (Q biotype) cryptic species in a semipersistent manner. This study evaluated the impacts of CCYV on B. tabaci to better understand the plant-virus-vector interactions. By using CCYV-B. tabaci MED-cucumber as the model, we investigated whether or how a semipersistent plant virus impacts the biology of its whitefly vector. CCYV mRNAs were detectable in nymphs from first to fourth instars and adults of B. tabaci with different titers. Nymph instar durations and adult longevity of female whiteflies greatly extended on CCYV-infected plants, but nymph instar durations and adult longevity of male whiteflies were not significantly influenced. In addition, the body length and oviposition increased in adults feeding on CCYV-infected plants, but the hatching rates of eggs and survival rates of different stages were not affected. Most interestingly, the sex ratio (male:female) significantly reduced to 0.5:1 in whitefly populations on CCYV-infected plants, while the ratio remained about 1:1 on healthy plants. These results indicated that CCYV can significantly impact the biological characteristics of its vector B. tabaci. It is speculated that CCYV and B. tabaci have established a typical mutualist relationship mediated by host plants.

Haplotype-resolved genome assembly provides insights into evolutionary history of the tea plant Camellia sinensis.

Tea is an important global beverage crop and is largely clonally propagated. Despite previous studies on the species, its genetic and evolutionary history deserves further research. Here, we present a haplotype-resolved assembly of an Oolong tea cultivar, Tieguanyin. Analysis of allele-specific expression suggests a potential mechanism in response to mutation load during long-term clonal propagation. Population genomic analysis using 190 Camellia accessions uncovered independent evolutionary histories and parallel domestication in two widely cultivated varieties, var. sinensis and var. assamica. It also revealed extensive intra- and interspecific introgressions contributing to genetic diversity in modern cultivars. Strong signatures of selection were associated with biosynthetic and metabolic pathways that contribute to flavor characteristics as well as genes likely involved in the Green Revolution in the tea industry. Our results offer genetic and molecular insights into the evolutionary history of Camellia sinensis and provide genomic resources to further facilitate gene editing to enhance desirable traits in tea crops.

Are Yellow Sticky Cards and Light Traps Effective on Tea Green Leafhoppers and Their Predators in Chinese Tea Plantations?

In Chinese tea plantations, yellow sticky cards and light traps are increasingly used to control insect pests, especially the tea green leafhopper Empoasca onukii. In this study, a 16-week open-field experiment with daily weather monitoring was designed to test the responses of tea green leafhopper, parasitoids and spiders to yellow sticky cards and three light traps with different wavelengths (covered with sticky cards). An exclosure experiment was also designed to further test the influence of the three light systems (without sticky card) on the same species. The results showed that all three light emitting diode (LED) light traps (white, green and yellow) and yellow sticky cards attracted many more E. onukii male adults than females during the course of the open field experiment, with less than 25% of trapped adults being females. Parasitoids and spiders were also attracted by these systems. Weather variables, especially rainfall, influenced the trapping efficiency. In the exclosure experiment, the population of leafhoppers in the yellow sticky card treatment did not decline significantly, but the number of spiders significantly decreased. The green and white light treatments without sticky cards showed a significant control of E. onukii and no obvious harm to spiders. These results suggest that yellow sticky cards and light traps have limited capacity to control tea green leafhoppers. However, light, especially green light, may be a promising population control measure for tea green leafhoppers, not as killing agents in the traps, but rather as a behavioral control system.