The Impact of HVDC Links on Transmission System Collapse

Modern power systems are continually being expanded, are required to carry more power and are being increasingly interconnected. All of these increase the risk of wide area blackout.In 2003 the North America Blackout demonstrated that a HVDC link provides a ‘firewall’ against the system collapse propagating through a network. The HVDC link between Quebec and New York ensured that the system collapse did not progress beyond the HVDC interconnection interface. The objectives of this paper are to investigate contributions that integrate HVDC interconnections into AC networks. The simulation studies were performed using MATLAB

Organic Matter Regulates Ammonia-Oxidizing Bacterial and Archaeal Communities in the Surface Sediments of Ctenopharyngodon idellus Aquaculture Ponds

Ammonia-oxidizing bacteria (AOB) and archaea (AOA) play important roles in nitrogen removal in aquaculture ponds, but their distribution and the environmental factors that drive their distribution are largely unknown. In this study, we collected surface sediment samples from Ctenopharyngodon idellus ponds in three different areas in China that practice aquaculture. The community structure of AOB and AOA and physicochemical characteristics in the ponds were investigated. The results showed that AOA were more abundant than AOB in all sampling ponds except one, but sediment AOB and AOA numbers varied greatly between ponds. Correlation analyses indicated a significant correlation between the abundance of AOB and arylsulfatase, as well as the abundance of AOA and total nitrogen (TN) and arylsulfatase. In addition, AOB/AOA ratio was found to be significantly correlated with the microbial biomass carbon. AOB were grouped into seven clusters affiliated to Nitrosospira and Nitrosomonas, and AOA were grouped into six clusters affiliated to Nitrososphaera, Nitrososphaera sister group, and Nitrosopumilus. AOB/AOA diversity in the surface sediments of aquaculture ponds varied according to the levels of total organic carbon (TOC), and AOB and AOA diversity was significantly correlated with arylsulfatase and β-glucosidase, respectively. The compositions of the AOB communities were also found to be significantly influenced by sediment eutrophic status (TOC and TN levels), and pH. In addition, concentrations of acid phosphatase and arylsulfatase in surface sediments were significantly correlated with the prominent bacterial amoA genotypes, and concentrations of TOC and urease were found to be significantly correlated with the prominent archaeal amoA genotype compositions. Taken together, our results indicated that AOB and AOA communities in the surface sediments of Ctenopharyngodon idellus aquaculture ponds are regulated by organic matter and its availability to the microorganisms

A new numerical modelling method for system energy efficiency calculation

This paper focuses on greenhouse gas emissions of new energy ships by investigating energy efficiency of the ships using solar photovoltaic system. According to the operating characteristics of the diesel generator set, a novel energy efficiency model of the generator diesel engine was established, where the solar photovoltaic system was included to analyze the model energy efficiency. In order to evaluate the feasibility and availability of the proposed model, experimental data acquired from the solar photovoltaic system testing, in a real-world large ro-ro ship, was collected and compared with the model output. The fuel consumption with and without the use of the solar photovoltaic system was used to analyze the ship\u27s energy efficiency. The comparison results demonstrate that the proposed energy efficiency model for marine generator diesel engines with solar photovoltaic system is able to represent the ship\u27s efficiency level, with an estimation error of 3.43 %

NEW ADVANCES IN THE DIAGNOSIS AND TREATMENT OF PEDIATRIC MIGRAINE

Migraine is one of the most common disabling neurological diseases in children and seriously affects the physical and mental health of children. The incidence and disability rates of migraine are gradually increasing in recent years, but its pathogenesis remains unclear. This article mainly reviews the clinical manifestations of pediatric migraine and the latest classification and diagnostic criteria, summarizes the pathophysiological mechanism of pediatric migraine and genetic research advances, and discusses the acute treatment, preventive treatment, and latest treatment methods for pediatric migraine

DNA methylation profiling to determine the primary sites of metastatic cancers using formalin-fixed paraffin-embedded tissues

Abstract Identifying the primary site of metastatic cancer is critical to guiding the subsequent treatment. Approximately 3–9% of metastatic patients are diagnosed with cancer of unknown primary sites (CUP) even after a comprehensive diagnostic workup. However, a widely accepted molecular test is still not available. Here, we report a method that applies formalin-fixed, paraffin-embedded tissues to construct reduced representation bisulfite sequencing libraries (FFPE-RRBS). We then generate and systematically evaluate 28 molecular classifiers, built on four DNA methylation scoring methods and seven machine learning approaches, using the RRBS library dataset of 498 fresh-frozen tumor tissues from primary cancer patients. Among these classifiers, the beta value-based linear support vector (BELIVE) performs the best, achieving overall accuracies of 81-93% for identifying the primary sites in 215 metastatic patients using top-k predictions (k = 1, 2, 3). Coincidentally, BELIVE also successfully predicts the tissue of origin in 81-93% of CUP patients (n = 68)

Co-occurrence and distribution of nitrite-dependent anaerobic ammonium and methane-oxidizing bacteria in a paddy soil

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