ABSTRACT
A good understanding of the power system resilience is necessary for optimizing the investment strategies and supporting the emergency rescue, but the existing quantitative estimation results based on real outage events are still lacked due to the data limitations. Therefore, this study first establishes a unified framework to measure the power system resilience under different natural disasters, by integrating the electricity performance curve with the dynamic inoperability input-output model. Then, a database of 285 Chinese historical big power outage events caused by natural disasters is established, and the city-level power system resilience values are estimated. Finally, a benefit analysis is conducted for improving the power system resilience. Our major findings are that: (1) Electricity system recoveries quickest from hail (23.05 h), while restores slowest from snowstorm (117.31 h). (2) China's city electricity system is the most resilient to the thunderstorm, while is the least resilient to the earthquake. (3) Enhancing the power system resilience will significantly reduce the requirements for rescue resources, and the saved emergency rescue cost ranges from 0.57 million yuan to 12.08 million yuan with 1% reduction of initial inoperability.
Subject(s)
Disasters , Natural Disasters , Cities , China , ElectricityABSTRACT
Quantifying the relationship between the chemical weathering and denudation rates of active orogenic belts over a range of climates is the key to addressing the controversy over the uplift-weathering hypothesis. However, studies have focused on warm and humid environments and have not examined cold and arid environments. Here, we present a new dataset of the chemical depletion fraction (CDF: ratio of the chemical weathering rate to the total denudation rate) across the arid to semiarid Qilian Mountains on the northeastern Tibetan Plateau, where the uplift-weathering hypothesis has been proposed. We selected 60 points from 12 catchments in the middle Qilian Mountains. At each point, we collected three samples (soil, saprolite, and bedrock samples) and calculated the CDF values based on their Zr concentrations. We found no clear correlation between the CDF and climatic factors (temperature, precipitation, and normalized difference vegetation index (NDVI)), topographic factors (slope and local relief), and denudation rate. The calculated chemical weathering rates, nevertheless, are positively correlated with precipitation, NDVI, and denudation rate, and negatively correlated with temperature. This result indicates that the Qilian Mountains are under supply-limited conditions, even at high denudation rates (>800 t km-2 y-1). We speculate that low temperatures (<0 °C) could intensify near-surface chemical weathering by promoting the physical breakdown of the bedrock and increasing soil water availability. This mechanism causes a compensation effect maintaining the supply-limited conditions in landscapes with high denudation rates. Combing a worldwide dataset regarding the correlations between CDF and climatic factors and denudation rates, we argue that intensified denudation since the late Cenozoic contributed to global cooling.
ABSTRACT
Salmonella enteritidis and Salmonella pullorum belonging to Group O9 Salmonella are major causative agents of infectious diseases in chicken. O9 antigen as a part of lipopolysaccharide (LPS) is a predominant detected target for Salmonella infection. To identify the infection, an anti-O9 monoclonal antibody (McAb)-based direct competitive enzyme-linked assay (O9 Dc-ELISA) was developed after constraints were optimized; the establishment and application of O9 Dc-ELISA, compared to two commercial kits and plate agglutination test (PAT), showed that O9 Dc-ELISA could screen out more positive samples than the PAT method could and produce the same agreement rates with commercial kits in terms of sensitivity in addition to strong specificity to clinical serum samples.
ABSTRACT
A key feature of the fowl-specific pathogen Salmonella Pullorum is its vertical transmission to progeny via the egg. In this study, PCR signature-tagged mutagenesis identified nine genes of a strain of S. Pullorum that contributed to survival in the chicken embryo during incubation. The genes were involved in invasion, cell division, metabolism and bacterial defence. The competition index in vivo and in vitro together with a virulence evaluation for chicken embryos of all nine mutant strains confirmed their attenuation.
