279 research outputs found

    An automatic identification algorithm of internal solitary wave for mooring data based on geometric characteristics of the flow field

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    Internal solitary wave (ISW) is one of the most important sub-mesoscale phenomenas in the ocean, and detection of which is of utmost significance for marine exploitation, ecological environment protection and military affairs. Therefore, in this study, an automatic algorithm for the identification of ISWs was proposed based on the geometric characteristics of the flow field. The algorithm was applied to calculate the characteristic parameters of the ISWs and its reliability was further verified, indicating that the algorithm can effectively detect the ISWs and provide a reference for preventing and avoiding ISWs in ocean engineering

    Simulating infrastructure networks in the Yangtze River Delta (China) using generative urban network models

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    This paper explores the urban-geographical potential of simulation approaches combining spatial and topological processes. Drawing on Vértes et al.'s (2012) economical clustering model, we propose a generative network model integrating factors captured in traditional spatial models (e.g., gravity models) and more recently developed topological models (e.g., actor-oriented stochastic models) into a single framework. In our urban network-implementation of the generative network model, it is assumed that the emergence of inter-city linkages can be approximated through probabilistic processes that speak to a series of contradictory forces. Our exploratory study focuses on the outline of the infrastructure networks connecting prefecture-level cities in the highly urbanized Yangtze River Delta (China). Possible hampering factors in the emergence of these networks include distance and administrative boundaries, while stimulating factors include a measure of city size (population, gross domestic product) and a topological rule stating that the formation of connections between cities sharing nearest neighbors is more likely (i.e., a transitive effect). Based on our results, two wider implications of our research are discussed: (1) it confirms the potential of the proposed method in urban network simulation in that the inclusion of a topological factor alongside geographical factors generates an urban network that better approximates the observed network; (2) it allows exploring the differential extent to which driving forces influence the structure of different urban networks. For instance, in the Yangtze River Delta, transitivity plays a less important role in the Internet-network formation; GDP and boundaries more strongly affect the rail network; and distance decay effects play a more prominent role in the road network

    Salvia miltiorrhiza injection ameliorates myocardial ischemia-reperfusion injury via downregulation of PECAM-1

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    Purpose: To investigate the effect of Salvia miltiorrhiza injection on myocardial ischemia-reperfusion injury and PECAM-1 related pathways. Method: Male Wistar rats were used for establishment of myocardial ischemia-reperfusion model. The rats were randomly assigned to four groups: experimental group, low dose group (Salvia miltiorrhiza injection, 10 mL/kg/day), moderate dose group (Salvia miltiorrhiza injection, 20 mL/kg/day) and high dose group (Salvia miltiorrhiza injection, 40 mL/kg/day). Myocardial ischemia-reperfusion model was established in the four groups. Evans-TTC staining was used to assess relative area of ischemiareperfusion injury. Blood samples were collected for assay of PECAM-1 expression using enzymelinked immunosorbent assay (ELISA). Fresh blood platelets were collected in all groups, and divided into two groups - control group (normal culture) and experimental group (Salvia miltiorrhiza injection). The expression of PECAM-1 in blood platelets was assayed using Western blot. Result: Compared with the experimental group, Salvia miltiorrhiza injection ameliorated myocardial ischemia-reperfusion injury, and decreased the infarction area seen in Evans/TTC staining. PECAM-1 expression in blood was decreased by Salvia miltiorrhiza injection. Blood platelets dysfunction was induced after myocardial ischemia-reperfusion, and the level of PECAM-1 increased. However, Salvia miltiorrhiza injection treatment downregulated the expression of PECAM-1 after myocardial ischemiareperfusion. Conclusion: Salvia miltiorrhiza injection maintains normal function of blood platelets and ameliorates myocardial ischemia-reperfusion injury by decreasing expression of PECAM-1

    Development and Characterization of Microsatellite Loci for Ficus hirta (Moraceae)

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    Microsatellite primers were developed to investigate population genetic structure in Ficus hirta (Moraceae). Sixteen microsatellite primers were developed and optimized for F. hirta using Illumina paired-end sequencing of pre-receptive and receptive developmental-phase female flowers. Out of 16 primers, nine were found to be polymorphic in four populations of F. hirta. Alleles per locus ranged from two to 15 across the 94 F. hirta individuals, while within-population observed and expected heterozygosity per locus ranged from 0.000 to 0.955 and from 0.000 to 0.882, respectively. In addition, the 16 primers were tested in 29 additional Ficus species, with all found to amplify in at least 11 of these species and with most amplifying in a majority of the species. This set of microsatellite primers is the first specifically developed for F. hirta and will facilitate studies of genetic diversity within and genetic differentiation among populations of Ficus species

    Research on service quality of professional education based on the PZB service quality model

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    With the arrival of Internet technology and the information era, China’s higher education has entered a new stage of development. In this context, new learning methods represented by “Internet+” have gradually emerged and rapidly spread, and traditional classroom teaching is facing a huge impact. At the same time, more and more students choose to learn independently through online courses due to resource constraints, time and space. This new learning method has posed a great challenge to the traditional education concept. Therefore, how to improve the quality of college education services has become one of the urgent problems to be solved at present. In this paper, from the perspective of service quality of college education, it is of practical significance to apply the theory of hybrid service quality to college hybrid education to explore its service quality improvement strategy. In this paper, the application of the PZB service quality model in professional education teaching is studied and discussed by using the methods of literature, mathematical statistics, and logical analysis. In this paper, the structure of the service quality evaluation system, influencing factors and results analysis, and the summary of improvement suggestions are deeply analyzed

    Trade-induced atmospheric mercury deposition over China and implications for demand-side controls

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    Mercury (Hg) is of global concern because of its adverse effects on humans and the environment. In addition to long-range atmospheric transport, Hg emissions can be geographically relocated through economic trade. Here, we investigate the effect of China’s interregional trade on atmospheric Hg deposition over China, using an atmospheric transport model and multiregional input-output analysis. In general, total atmospheric Hg deposition over China is 408.8 Mg yr-1, and 32% of this is embodied in China’s interregional trade, with the hotspots occurring over Gansu, Henan, Hebei, and Yunnan provinces. Interprovincial trade considerably redistributes atmospheric Hg deposition over China, with a range in deposition flux from −104% to +28%. Developed regions, such as the Yangtze River Delta (Shanghai, Jiangsu, and Zhejiang) and Guangdong, avoid Hg deposition over their geographical boundaries, instead causing additional Hg deposition over developing provinces. Bilateral interaction among provinces is strong over some regions, suggesting a need for joint mitigation, such as the Jing-Jin-Ji region (Beijing, Tianjin, and Hebei) and the Yangtze River Delta. Transferring advanced technology from developed regions to their developing trade partners would be an effective measure to mitigate China’s Hg pollution. Our findings are relevant to interprovincial efforts to reduce trans-boundary Hg pollution in China

    The serum matrix metalloproteinase-9 level is an independent predictor of recurrence after ablation of persistent atrial fibrillation

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    OBJECTIVES: This study investigated whether the serum matrix metalloproteinase-9 level is an independent predictor of recurrence after catheter ablation for persistent atrial fibrillation. METHODS: Fifty-eight consecutive patients with persistent atrial fibrillation were enrolled and underwent catheter ablation. The serum matrix metalloproteinase-9 level was detected before ablation and its relationship with recurrent arrhythmia was analyzed at the end of the follow-up. RESULTS: After a mean follow-up of 12.1±7.2 months, 21 (36.2%) patients had a recurrence of their arrhythmia after catheter ablation. At baseline, the matrix metalloproteinase-9 level was higher in the patients with recurrence than in the non-recurrent group (305.77±88.90 vs 234.41±93.36 ng/ml, respectively, p=0.006). A multivariate analysis showed that the matrix metalloproteinase-9 level was an independent predictor of arrhythmia recurrence, as was a history of atrial fibrillation and the diameter of the left atrium. CONCLUSION: The serum matrix metalloproteinase-9 level is an independent predictor of recurrent arrhythmia after catheter ablation in patients with persistent atrial fibrillation
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