Search

In order to reasonably consider the effect of flexibility of the input peak ground motion along the sliding body on the critical sliding acceleration and cumulative sliding displacement, the combination of ant colony complex method with limit equilibrium methods is used to search the position of potential sliding body. Based on the principle of the rigid Newmark sliding model, the average yielding acceleration is considered as the critical acceleration during the analysis of sliding displacement. Analytical expressions of the average yielding acceleration are presented based on several common limit equilibrium methods. It is shown that the computational efficiency and accuracy of the refined Newmark sliding method based on the average yielding acceleration have been improved significantly. [ABSTRACT FROM AUTHOR]

Based on the thermodynamic method, dynamic dissipative properties and deformation mechanisms are studied in depth. Starting from the skeleton curve and hysteresis loop of Hardin -- Drnevich model for soils, the dynamic incremental dissipation function is constructed by use of assumption of translation rule of the back stress, in which the shift stress is assumed to be the product by the plastic modulus and the internal variable. It is indicated that the constructed function automatically satisfies thermodynamical requirements. And effects of the form, the change law of yield curve in the corresponding p - q true stress space, and material parameters on the yield curve are discussed. The results show that the yield curves in the p - q true stress space appear as a straight line, and the anticlockwise rotation will occur with the increased material parameters. [ABSTRACT FROM AUTHOR]

The stability analysis on two typical slopes was performed by local factor of safety method in order to study the effect of constraints in the dual optimization problem on the obtained results. The constraints consist of the limits to the boundary interslice normal, shear forces, and normal forces acting on the slice base in the maximization problem as well as the limits to the potential slip surfaces in the minimization problem. The analysis indicates that rational results of local factor of safety method can be obtained when the interslice normal force is positive and the interslice shear force is negative. [ABSTRACT FROM AUTHOR]

A simplified procedure for evaluating seismic stability of high core type rock-fill dam subjected to earthquake shaking, in which the integrated effect of equivalent nodal force and step-by-step gradually softening modulus is taken into account, is presented based on whole earthquake deformation analysis. The fundamental feature of this procedure is the modified relationship of stress and strain by residual shear strain potential and residual volumetric strain potential in dynamic time-history analysis. In the meanwhile, the effect of the residual dynamic pore water pressure on the maximum shear modulus is considered. The numerical computations are performed by using the proposed method. It is shown that the time-history accumulative permanent displacement for a given core dam, in which earthquake effect is properly considered, is more rational compared with the conventional computational results. [ABSTRACT FROM AUTHOR]

Sclerotinia sclerotiorum is an economically damaging fungal pathogen that causes Sclerotinia stem rot in leguines, producing enormous yield losses. This pathogen is difficult to control due to its wide host spectrum and ability to produce sclerotia. which are resistant bodies that can remain active for long periods under harsh environmental conditions. Here, the biocontrol methods for the management of S. sclerotiorum in legumes are reviewed. Baciltus strains, which synthesized lipopeptides and volatile organic compounds, showed high efficacies in soybean plants, whereas the highest efficacies for the control of the pathogen in alfalfa and common bean were observed when using Coniothyrium minitans and Streptomyces spp., respectively. The biocontrol efficacies in fields were under 65%, highlighting the lack of strategies to achieve a complete control. Overall, although most studies involved extensive sci·eenings using different biocontrol agent concentrations and application conditions, there is a lack of knowledge regarding the specific anti fungal mechanisms, which limits the optimization of the reported methods. [ABSTRACT FROM AUTHOR]

Thiram is a toxic fungicide extensively used for the management of pathogens in fruits. Although it is known that thiram degrades in plant tissues, the key enzymes involved in this process remain unexplored. In this study, we report that a tau class glutathione S-transferase (GST) from Carica papaya can degrade thiram. This enzyme was easily obtained by heterologous expression in Escherichia coli, showed low promiscuity toward other thiuram disulfides, and catalyzed thiram degradation under physiological reaction conditions. Site-directed mutagenesis indicated that G-site residue S67 shows a key in- fluence for the enzymatic activity toward thiram, while mutation of residue S13, which reduced the GSH oxidase activity, did not significantly affect the thiram-degrading activity. The formation of dimethyl dithiocarbamate, which was subsequently converted into carbon disulfide, and dimethyl dithiocarbamoylsulfenic acid as the thiram degradation products suggested that thiram undergoes an alkaline hydrolysis that involves the rupture of the disulfide bond. Application of the GST selective inhibitor 4- chloro-7-nitro-2,1,3-benzoxadiazole reduced papaya peel thiram-degrading activity by 95%, indicating that this is the main degradation route of thiram in papaya. GST from Carica papaya also catalyzed the degradation of the fungicides chlorothalonil and thiabendazole, with residue S67 showing again a key influence for the enzymatic activity. These results fill an important knowledge gap in understanding the catalytic promiscuity of plant GSTs and reveal new insights into the fate and degradation products of thiram in fruits. [ABSTRACT FROM AUTHOR]

Testosterone (T), an environmental androgen, significantly disrupts endocrine systems in wildlife and ecosystems. Despite growing concern over its high levels in aquatic environments, the reproductive toxicity of testosterone and its mechanisms are not well understood. In this study, we investigated the reproductive toxicity and mechanisms of testosterone using Caenorhabditis elegans (C. elegans) and assessed its ecological toxicity through the benchmark dose (BMD) method. Our results indicate that T concentrations exceeding 0.01 μg/L significantly reduce the brood size, decrease germ cell counts, and prolong the generation time in C. elegans as T concentrations increase. Furthermore, to elucidate the specific mechanisms, we analyzed the expression of nhr-69, mpk-1, and other genes involved in sex determination. These findings suggest that the nhr-69-mediated reproductive toxicity of T primarily affects sperm formation and the offspring number by influencing its downstream targets, mpk-1 and fog-1/3, which are critical in the germ cell sex-determining pathway. Additionally, this study determined that the 10% lower boundary of the baseline dose (BMDL10) is 1.160 ng/L, offering a more protective reference dose for the ecological risk assessment of T. The present study suggests that nhr-69 mediates the reproductive toxicity of T by influencing mpk-1 and fog-1/3, critical genes at the end of the germ cell sex-determining pathway, thereby providing a basis for establishing reproductive toxicity thresholds for T.

Event cameras are asynchronous sensors that operate in a completely different way from traditional cameras.Rather than catching pictures at a steady rate,event cameras measure light changes (called events) separately for every pixel.As a sequence,it alleviates the problems of traditional cameras in complex light conditions and scenes where objects move at high speed.With the development of convolutional neural networks,learning-based pattern recognition methods have made great progress in visual tasks such as optical flow estimation and target recognition by converting the output of the event camera into a pseudo-ima-ge representation.However,such methods abandon the temporal correlation between the event streams,so that the texture of the pseudo image is not clear enough,and it is difficult to extract the features.The key to solving this problem lies in how to model relevant information between events in the sample.Therefore,a neural network framework based on event stream partition algorithm is proposed,which explicitly integrates the temporal information of event streams.The framework divides the incoming stream of events into several parts,and a weight distribution network assigns different weights to each piece of the streams.Then,the framework uses convolutional neural network to fuse temporal information and extract advanced features.Finally,the input sample is classified.We thoroughly validate the proposed framework on object recognition.Comparison experiments on N-Caltech101 and N-cars datasets show that the proposed framework has a significant improvement in classification accuracy compared with the most advanced existing algorithms.