18,808 research outputs found

    Conformal Ricci flow on asymptotically hyperbolic manifolds

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    In this article we study the short-time existence of conformal Ricci flow on asymptotically hyperbolic manifolds. We also prove a local Shi's type curvature derivative estimate for conformal Ricci flow.Comment: 19 pages. No figur

    Empirical Study on the Financial Development to Promote the Urbanization Process in China: A Case of Hubei Province

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    As the central province, Hubei is a typical area of urbanization in China. Analysis of Hubei economic development has a certain representation in the process of urbanization. Since 1990s, research on 25 years of data and practices in Hubei shows that three major finance industries in Hubei, including banking, securities, and insurance, have played an important role in the process of urbanization. In the aspects of agricultural industries, urban construction, and industrial structure, the development of finance has promoted the process in agricultural industries, population urbanization, and industrialization

    Timed Fault Tree Models of the China Yongwen Railway Accident

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    Safety is an essential requirement for railway transportation. There are many methods that have been developed to predict, prevent and mitigate accidents in this context. All of these methods have their own purpose and limitations. This paper presents a new useful analysis technique: timed fault tree analysis. This method extends traditional fault tree analysis with temporal events and fault characteristics. Timed Fault Trees (TFTs) can determine which faults need to be eliminated urgently, and it can also provide a safe time window to repair them. They can also be used to determine the time taken for railway maintenance requirements, and thereby improve maintenance efficiency, and reduce risks. In this paper, we present the features and functionality of a railway transportation system based on timed fault tree models. We demonstrate the applicability of our framework via a case study of the China Yongwen line railway accident

    G ā€scores: A method for identifying diseaseā€causing pathogens with application to lower respiratory tract infections

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    Lower respiratory tract infections (LRTIs) are well known for the lack of a good diagnostic method. The main difficulty lies in the fact that there are a variety of pathogens causing LRTIs, and their management and treatment are quite different. The development of quantitative realā€time loopā€mediated isothermal amplification (qrtā€LAMP) made it possible to rapidly amplify and quantify multiple pathogens simultaneously. The question that remains to be answered is how accurate and reliable is this method? More importantly, how are qrtā€LAMP measurements utilized to inform/suggest medical decisions? When does a pathogen start to grow out of control and cause infection? Answers to these questions are crucial to advise treatment guidance for LRTIs and also helpful to design phase I/II trials or adaptive treatment strategies. In this article, our main contributions include the following two aspects. First, we utilize zeroā€inflated mixture models to provide statistical evidence for the validity of qrtā€LAMP being used in detecting pathogens for LRTIs without the presence of a gold standard test. Our results on qrtā€LAMP suggest that it provides reliable measurements on pathogens of interest. Second, we propose a novel statistical approach to identify diseaseā€causing pathogens, that is, distinguish the pathogens that colonize without causing problems from those that rapidly grow and cause infection. We achieve this by combining information from absolute quantities of pathogens and their symbiosis information to form G ā€scores. Changeā€point detection methods are utilized on these G ā€scores to detect the three phases of bacterial growthā€”lag phase, log phase, and stationary phase. Copyright Ā© 2014 John Wiley & Sons, Ltd.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/107530/1/sim6129-sup-0001-supplemental_new.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/107530/2/sim6129.pd

    The Radiation Structure of PSR B2016++28 Observed with FAST

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    With the largest dish Five-hundred-meter Aperture Spherical radio Telescope (FAST), both the mean and single pulses of PSR B2016++28, especially including the single-pulse structure, are investigated in detail in this study. The mean pulse profiles at different frequencies can be well fitted in a conal model, and the peak separation of intensity-dependent pulse profiles increases with intensity. The integrated pulses are obviously frequency dependent (pulse width decreases by āˆ¼ā€‰20%\sim\,20\% as frequency increases from 300 MHz to 750 MHz), but the structure of single pulses changes slightly (the corresponding correlation scale decreases by only āˆ¼ā€‰1%\sim\,1\%). This disparity between mean and single pulses provides independent evidence for the existence of the RS-type vacuum inner gap, indicating a strong bond between particles on the pulsar surface. Diffused drifting sub-pulses are analyzed. The results show that the modulation period along pulse series (P3P_3) is positively correlated to the separation between two adjacent sub-pulses (P2P_2). This correlation may hint a rough surface on the pulsar, eventually resulting in the irregular drift of sparks. All the observational results may have significant implications in the dynamics of pulsar magnetosphere and are discussed extensively in this paper.Comment: Sci. China-Phys. Mech. Astron. 62, 959505 (2019
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