18,808 research outputs found
Conformal Ricci flow on asymptotically hyperbolic manifolds
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
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
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 āscores: A method for identifying diseaseācausing pathogens with application to lower respiratory tract infections
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 realātime loopāmediated isothermal amplification (qrtāLAMP) 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 qrtāLAMP 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 zeroāinflated mixture models to provide statistical evidence for the validity of qrtāLAMP being used in detecting pathogens for LRTIs without the presence of a gold standard test. Our results on qrtāLAMP suggest that it provides reliable measurements on pathogens of interest. Second, we propose a novel statistical approach to identify diseaseācausing 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 āscores. Changeāpoint detection methods are utilized on these G āscores to detect the three phases of bacterial growthālag 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 B201628 Observed with FAST
With the largest dish Five-hundred-meter Aperture Spherical radio Telescope
(FAST), both the mean and single pulses of PSR B201628, 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 as frequency increases from 300 MHz to 750 MHz), but
the structure of single pulses changes slightly (the corresponding correlation
scale decreases by only ). 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 () is positively correlated to the separation
between two adjacent sub-pulses (). 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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