Pattern Recognition of Partial Discharge Faults in Switchgear Using a Back Propagation Neural Network Optimized by an Improved Mantis Search Algorithm.

The dependable functioning of switchgear is essential to maintain the stability of power supply systems. Partial discharge (PD) is a critical phenomenon affecting the insulation of switchgear, potentially leading to equipment failure and accidents. PDs are generally grouped into metal particle discharge, suspended discharge, and creeping discharge. Different types of PDs are closely related to the severity of a PD. Partial discharge pattern recognition (PDPR) plays a vital role in the early detection of insulation defects. In this regard, a Back Propagation Neural Network (BPNN) for PDPR in switchgear is proposed in this paper. To eliminate the sensitivity to initial values of BPNN parameters and to enhance the generalized ability of the proposed BPRN, an improved Mantis Search Algorithm (MSA) is proposed to optimize the BPNN. The improved MSA employs some boundary handling strategies and adaptive parameters to enhance the algorithm's efficiency in optimizing the network parameters of BPNN. Principal Component Analysis (PCA) is introduced to reduce the dimensionality of the feature space to achieve significant time saving in comparable recognition accuracy. The initially extracted 14 feature values are reduced to 7, reducing the BPNN parameter count from 183 with 14 features to 113 with 7 features. Finally, numerical results are presented and compared with Decision Tree (DT), k-Nearest Neighbor classifiers (KNN), and Support Vector Machine (SVM). The proposed method in this paper exhibits the highest recognition accuracy in metal particle discharge and suspended discharge.

Low-frequency variability in theta activity modulates the attention-fluctuation across task and resting states.

Sustained attention is not constant but fluctuates influencing our task performance. Albeit intensive investigations, it remains unclear whether the attention-fluctuation during tasks is derived from its spontaneous fluctuation in the resting state. Here, we addressed this issue by investigating the attention-fluctuation in both task and resting states, through the EEG measurement of theta-variability. We found significant rest-task modulation of theta-variability, i.e., reduced theta-variability in the task state compared to the resting state. This task and rest modulation was manifested in the low-frequency of theta-variability (<0.1 Hz). Furthermore, the low-frequency theta-variability exhibited a significant rest-task correlation, however, only the low-frequency theta-variability in the task state but not in the resting state was correlated with the behavioral performance. These findings shed light on the low-frequency feature of attention-fluctuation, and advanced our understanding of sustained attention by suggesting that the theta-variability in low-frequencies was relevant to attention level in task state.

Default mode network mediates low-frequency fluctuations in brain activity and behavior during sustained attention.

The low-frequency (<0.1 Hz) fluctuation in sustained attention attracts enormous interest in cognitive neuroscience and clinical research since it always leads to cognitive and behavioral lapses. What is the source of the spontaneous fluctuation in sustained attention in neural activity, and how does the neural fluctuation relate to behavioral fluctuation? Here, we address these questions by collecting and analyzing two independent fMRI and behavior datasets. We show that the neural (fMRI) fluctuation in a key brain network, the default-mode network (DMN), mediate behavioral (reaction time) fluctuation during sustained attention. DMN shows the increased amplitude of fluctuation, which correlates with the behavioral fluctuation in a similar frequency range (0.01-0.1 Hz) but not in the lower (<0.01 Hz) or higher (>0.1 Hz) frequency range. This was observed during both auditory and visual sustained attention and was replicable across independent datasets. These results provide a novel insight into the neural source of attention-fluctuation and extend the former concept that DMN was deactivated in cognitive tasks. More generally, our findings highlight the temporal dynamic of the brain-behavior relationship.

Spinetoram resistance drives interspecific competition between Megalurothrips usitatus and Frankliniella intonsa.

BACKGROUND: Species displacement by the outcome of interspecific competition is of particular importance to pest management. Over the past decade, spinetoram has been extensively applied in control of the two closely related thrips Megalurothrips usitatus and Frankliniella intonsa worldwide, while whether its resistance is implicated in mediating interspecific interplay of the two thrips remains elusive to date. RESULTS: Field population dynamics (from 2017 to 2019) demonstrated a trend toward displacement of F. intonsa by M. usitatus on cowpea crops, supporting an existing interspecific competition. Following exposure to spinetoram, M. usitatus became the predominate species, which suggests the use of spinetoram appears to be responsible for mediating interspecific interactions of the two thrips. Further annual and seasonal analysis (from 2016 to 2020) of field-evolved resistance dynamics revealed that M. usitatus developed remarkably higher resistance to spinetoram compared to that of F. intonsa, implying a close relationship between evolution of spinetoram resistance and their competitive interactions. After 12 generations of laboratory selection, resistance to spinetoram in M. usitatus and F. intonsa increased up to 64.50-fold and 28.33-fold, and the average realized heritability (h2 ) of resistance was calculated as 0.2550 and 0.1602, respectively. Interestingly, two-sex life table analysis showed that the spinetoram-resistant strain of F. intonsa exhibited existing fitness costs, but not the M. usitatus. These indicate that a rapid development of spinetoram resistance and the lack of associated fitness costs may be the mechanism underlying recent dominance of M. usitatus over F. intonsa. CONCLUSION: Collectively, our results uncover the involvement of insecticide resistance in conferring displacement mechanism behind interspecific competition, providing a framework for understanding the significance of the evolutionary relationships among insects under ongoing changing environments. These findings also can be invaluable in proposing the most appropriate strategies for sustainable thrips control programs. © 2022 Society of Chemical Industry.

2-D Green's functions for semi-infinite orthotropic piezothermoelastic plane.

Green's functions play an important role in electroelastic analyses of piezoelectric media. However, most works available on the topic are for the case of uniform temperature. Based on the compact 2-D general solution of orthotropic piezothermoelectric material, which is expressed in harmonic functions, and employing the trial-and-error method, the 2-D Green's function for a steady line heat source in a semi-infinite piezothermoelectric plane is presented by four newly induced harmonic functions. All components of the coupled field are expressed in terms of elementary functions and are convenient to use. Numerical results are given graphically by contours.

[Study on drug-guide effect of Achyranthes bidentata in Sanmiao pill in arthritic rats].

OBJECTIVE: To study the drug-guiding mechanism of Achyranthes bidentata from Sanmiao pill in arthritic rats. METHOD: The rats were treated by Ferud's complet adjuvant and hot water -bath to establish rat adjuvant arthritis model, then the model rats were divided into three groups, model group, Sanmiao pill groups with A. bidentata. (18 g x kg(-1)) and without A. bidentata. (10 g x kg(-1)), respectively. The heart and foot joints were washed and homogenated to determine the berberine concentration by HPCL in different time after ig and the foot edema was tested by volume method. The pathological changes were observed and hemorheologic parameters were also tested. RESULT: The berberine concentration of foot joint was significantly higher in 2, 4, 6 hour and 14 day in the rats with A. bidentata. The berberine concentration ratio of foot joint and heart was significantly higher in rats with A. bidentata. pharmacodynamic researches showed that A. bidentata could enhance the edema inhibition effect of Sanmiao pill. Hemorheologic researches showed that A. bidentata. could significantly improve the blood viscosity of model rats, the blood high shear viscosity, the blood low shear viscosity and the plasma viscosity were (6.47 +/- 0.57), (9.28 +/- 1.2), (1.94 +/- 0.19) mPa x s respectively. CONCLUSION: A. bidentata. could facilitate the targeted tissue distribution of berberine. The effect was correlative with its blood viscosity improvement.