Eulerian Algorithms for Computing the Forward Finite Time Lyapunov Exponent Without Finite Difference upon the Flow Map

In this paper, effective Eulerian algorithms are introduced for the computation of the forward finite time Lyapunov exponent (FTLE) of smooth flow fields. The advantages of the proposed algorithms mainly manifest in two aspects. First, previous Eulerian approaches for computing the FTLE field are improved so that the Jacobian of the flow map can be obtained by directly solving a corresponding system of partial differential equations, rather than by implementing certain finite difference upon the flow map, which can significantly improve the accuracy of the numerical solution especially near the FTLE ridges. Second, in the proposed algorithms, all computations are done on the fly, that is, all required partial differential equations are solved forward in time, which is practically more natural. The new algorithms still maintain the optimal computational complexity as well as the second order accuracy. Numerical examples demonstrate the effectiveness of the proposed algorithms.     

Occurrence and distribution of antibiotics in surface water

Ecotoxicology - The concentrations, distribution, and ecological risks of 24 typical antibiotics in Hong Kong rivers and seawater were investigated using high-performance liquid chromatography...     

A National Analysis of Minimally Invasive Vs Open Segmentectomy for Stage IA Non–Small-Cell Lung Cancer

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Secondary stone formation 8 weeks after percutaneous nephrolithotomy treatment: A case report

Introduction:This work reports a patient with recurrent renal calculi subjected to three surgeries in half a year to be in the same position, and the high-throughput sequencing data showed different species in the renal pus and urine samples, which suggested that partial renal infection or stone formation can be judged by the bacteria in urine.Patient concerns:The female patient aged 43 years was referred to the authors’ department on April 13, 2020, due to left waist pain and fever for 3 days.Diagnosis:Kidney stones and hydronephrosis were determined by a urinary system computed tomography scan.Interventions:On April 20, 2020 and June 15, 2020, the patient was successfully treated with left percutaneous nephrolithotomy twice under general anesthesia. An investigation on the health and eating habits of the patient within 6 months was completed at the last admission. The components of the second renal calculus sample were analyzed with an infrared spectrum analyzer. The third renal stone (renal pus, triplicates) was subjected to microbial metagenome sequencing, and urine samples before and after surgery were subjected to 16S RNA sequencing by SEQHEALTH (Wuhan, China).Outcomes:After percutaneous nephrolithotomy, the left kidney stones were basically cleared, stone analysis revealed that the main components were calcium oxalate monohydrate, silica, and a small amount of calcium oxalate dehydrate. Although the urine samples exhibited differences, the renal pus and urine sample shared a single species.Conclusion:It is not clear that the prospects of partial renal infection or stone formation can be judged by the bacteria in urine.     

医院信息化建设网络安全与防护问题研究

医院信息系统是医院业务不可或缺的部分，加强计算机网络安全治理与防护对医院信息化具有重要意义。从分析当前国内医院网络安全现状出发，总结医院网络安全存在的隐患和面临的挑战，提出纵深防御体系，网络架构演进和人员安全风险意识以及能力培养等方面的治理策略。