Fractional Frequency Transmission is a competitive technology for offshore wind power transmission. Modular Multilevel Matrix Converter (M 3 C) plays a key role in a Fractional Frequency Transmission System (FFTS) as the frequency changer. M 3 C is broadly considered as the AC-AC converter for the future with its attractive advantages in high voltage and high power applications. Due to the lack of a DC link, electrical quantities at different frequencies from two AC systems couple in M 3 C, resulting in a complex harmonic condition. Harmonics can lead to stability issues and its analysis is of great importance. This paper focuses on the harmonic analysis of M 3 C. The arm capacitor voltage ripples and the harmonic currents are analyzed at various frequencies. Major factors influencing the harmonics magnitude are discussed. Analysis is conducted on sub-module capacitance and arm inductance selection. A zero-sequence current mitigation controller for M 3 C is implemented and tested. It is found that for a FFTS, some current harmonics flow into AC systems even though the system is balanced, while the others circulate within the converter. The theoretical harmonic analysis is verified by simulations in Real Time Digital Simulator (RTDS) of a M 3 C system where each arm consists of forty sub-modules. Index Terms-Fractional frequency transmission system, harmonic analysis, modular multilevel matrix converter (M 3 C), offshore wind power, energy storage. I. INTRODUCTION U NDER the pressure of fossil energy depletion and environmental pollution, renewable energy development has drawn worldwide attention. Offshore wind power is favored with merits of not taking up land in cities, rich and stable resource and suitability for large-scale development. Three main offshore Manuscript

Clubroot disease, which is caused by the soil-borne pathogen Plasmodiophora brassicae War (P. brassicae), is one of the oldest and most destructive diseases of Brassica and cruciferous crops in the world. Plant microRNAs [micro ribonucleic acids (miRNAs)] play important regulatory roles in several developmental processes. Although the role of plant miRNAs in plant-microbe interaction has been extensively studied, there are only few reports on the specific functions of miRNAs in response to P. brassicae. This study investigated the roles of miRNAs and their targets during P. brassicae infection in a pair of Brassica napus near-isogenic lines (NILs), namely clubroot-resistant line 409R and clubroot-susceptible line 409S. Small RNA sequencing (sRNA-seq) and degradome-seq were performed on root samples of 409R and 409S with or without P. brassicae inoculation. sRNA-seq identified a total of 48 conserved and 72 novel miRNAs, among which 18 had a significant differential expression in the root of 409R, while only one miRNA was differentially expressed in the root of 409S after P. brassicae inoculation. The degradome-seq analysis identified 938 miRNA target transcripts, which are transcription factors, enzymes, and proteins involved in multiple biological processes and most significantly enriched in the plant hormone signal transduction pathway. Between 409R and 409S, we found eight different degradation pathways in response to P. brassicae infection, such as those related to fatty acids. By combining published transcriptome data, we identified a total of six antagonistic miRNA-target pairs in 409R that are responsive to P. brassicae infection and involved in pathways associated with root development, hypersensitive cell death, and chloroplast metabolic synthesis. Our results reveal that P. brassicae infection leads to great changes in miRNA pool and target transcripts. More interestingly, these changes are different between 409R and 409S. Clarification of the crosstalk between miRNAs and their targets may shed new light on the possible mechanisms underlying the pathogen resistance against P. brassicae.

The wind turbine is usually integrated into the power grid via back to back converter, and the inertia is decreased. Virtual synchronous machine (VSM) control was proposed to improve inertia of the wind farm. While for the doubly-fed induction generator (DFIG)-based wind farm with traditional control strategy, sub-synchronous resonance (SSR) has become a significant problem when it is connected to series compensation transmission lines. Therefore, the impacts of VSM control strategy for DFIG on SSR need to be investigated. In this paper, a detailed small-signal stability analysis model of the VSM control strategy is first established and eigenvalue analysis is then carried out. SSR in the wind farm with the VSM control under different series compensation levels, controller parameters and wind speeds is analyzed, and it is also compared to that in the wind farm with the conventional vector control strategy (VC). Simulations are performed in PSCAD/EMTDC to verify the result of SSR analysis.

Multidrug-resistant (MDR) bacteria are important public health problems. Antibiotic susceptibility testing (AST) currently uses time-consuming culture-based procedures, which cause treatment delays and increased mortality. We developed a machine learning model using Acinetobacter baumannii as an example to explore a fast AST approach using metagenomic next-generation sequencing (mNGS) data.

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People's opinions change with time as they interact with each other. In a boundedconfidence model (BCM) of opinion dynamics, individuals (which are represented by the nodes of a network) have continuous-valued opinions and are influenced only by neighboring nodes whose opinions are within their confidence bound. In this paper, we formulate and analyze discrete-time BCMs with heterogeneous and adaptive confidence bounds. We introduce two new models: (1) a BCM with synchronous opinion updates that generalizes the Hegselmann-Krause (HK) and (2) a BCM with asynchronous opinion updates that generalizes the Deffuant-Weisbuch (DW) model. We analytically and numerically explore our adaptive BCMs' limiting behaviors, including the confidencebound dynamics, the formation of clusters of nodes with similar opinions, and the time evolution of an "effective graph", which is a time-dependent subgraph of a network with edges between nodes that can currently influence each other. For a wide range of parameters that control the increase and decrease of confidence bounds, we demonstrate for a variety of networks that our adaptive BCMs result in fewer major opinion clusters and longer convergence times than the baseline (i.e., nonadaptive) BCMs. We also show that our adaptive BCMs can have pairs of adjacent nodes that converge to the same opinion but are not able to influence each other. This qualitative behavior does not occur in the associated baseline BCMs.

Leaf color is a key trait that determines the ornamental quality of landscape tree species such as Acer tutcheri, and anthocyanin is the main pigment for red leaf coloration. Red leaf fading significantly reduces the ornamental value of A. tutcheri leaves in the spring; however, the physiological mechanism that causes red leaf discoloration in this species is still unclear. Only the anabolic or degradative metabolism of anthocyanin has been studied in terms of leaf color changes. In this study, leaves from four color-change stages of A. tutcheri during the spring were selected by the average sampling method, which involves measuring and analyzing the pigment content and physiological factors related to anthocyanin metabolism, aiming to clarify the key physiological factors of spring leaf coloration. Our results show that the reduced anthocyanin/chlorophyll ratio was the direct cause of red leaf fading in spring. The carbohydrates synthesized during the growth of juvenile leaves were mainly used for their growth and development, whereas fewer carbon sources were used for the synthesis of anthocyanin. Phenylalanine ammonia-lyase and chalcone isomerase activities increased in the early stages of juvenile leaf development and decreased in the middle and late stages, whereas peroxidase activity continued to increase. The decrease in anthocyanin synthesis-related enzyme activity reduced the accumulation of anthocyanin, whereas the increase in anthocyanin degradation-related enzyme activity accelerated the depletion of anthocyanin. Increasing vacuole pH was a major factor in the degradation of anthocyanin. The physiological characteristics of A. tutcheri leaves during the spring season suggest that anthocyanin is a key factor affecting the presentation of color in juvenile leaves, and red leaf fading in the spring of A. tutcheri is the result of the joint effect of the decrease in anthocyanin anabolic metabolism and the increase in anthocyanin degradative metabolism.

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