3,835 research outputs found
Influences of magnetic coupling process on the spectrum of a disk covered by the corona
Recently, much attention has been paid to the magnetic coupling (MC) process,
which is supported by very high emissivity indexes observed in Seyfert 1 galaxy
MCG-6-30-15 and GBHC XTE J1650-500. But the rotational energy transferred from
a black hole is simply assumed to be radiated away from the surrounding
accretion disk in black-body spectrum, which is obviously not consistent with
the observed hard power-law X-ray spectra. We intend to introduce corona into
the MC model to make it more compatible with the observations. We describe the
model and the procedure of a simplified Monte Carlo simulation, compare the
output spectra in the cases with and without the MC effects, and discuss the
influences of three parameters involved in the MC process on the output
spectra. It is shown that the MC process augments radiation fluxes in the UV or
X-ray band. The emergent spectrum is affected by the BH spin and magnetic field
strength at the BH horizon, while it is almost unaffected by the radial profile
of the magnetic field at the disk. Introducing corona into the MC model will
improve the fitting of the output spectra from AGNs and GBHCs.Comment: 15 pages, 5 figures, accepted by A&
Integrated cosparse analysis model with explicit edge inconsistency measurement for guided depth map upsampling
© 2018 SPIE and IS & T. A low-resolution depth map can be upsampled through the guidance from the registered high-resolution color image. This type of method is so-called guided depth map upsampling. Among the existing methods based on Markov random field (MRF), either data-driven or model-based prior is adopted to construct the regularization term. The data-driven prior can implicitly reveal the relation between color-depth image pair by training on external data. The model-based prior provides the anisotropic smoothness constraint guided by high-resolution color image. These types of priors can complement each other to solve the ambiguity in guided depth map upsampling. An MRF-based approach is proposed that takes both of them into account to regularize the depth map. Based on analysis sparse coding, the data-driven prior is defined by joint cosparsity on the vectors transformed from color-depth patches using the pair of learned operators. It is based on the assumption that the cosupports of such bimodal image structures computed by the operators are aligned. The edge inconsistency measurement is explicitly calculated, which is embedded into the model-based prior. It can significantly mitigate texture-copying artifacts. The experimental results on Middlebury datasets demonstrate the validity of the proposed method that outperforms seven state-of-the-art approaches
The effects of dog management on Echinococcus spp. prevalence in villages on the eastern Tibetan Plateau, China
Background The pastoral area of the eastern Tibetan plateau is a very important human echinococcosis endemic region. Domestic dogs are the main definitive host for the transmission of Echinococcus granulosus sensu lato (s.1.) and E. multilocularis to humans. To control the infection risks, a national-level canine echinococcosis prevention and control program has been implemented since 2015 in Shiqu County, Sichuan, China, The objective of this investigation was to evaluate its effect on Echinococcus spp. prevalence in dogs. Methods We surveyed 69 households with 84 owned dogs, for dog keeping information in the villages of Rizha and Eduoma. A total of 105 dog fecal samples, consisting of 75 from owned dogs and 30 unknown dog fecal samples were collected between 2015 and 2017 to determine Echinococcus spp. prevalence using copro-PCR. Eight variables based on household surveys were included into a logistic regression model for significantly relevant factors to canine echinococcosis prevalence in dogs. Results The overall Echinococcus spp. copro-DNA prevalence decreased significantly in dogs from 51.2% (2015) to 20.0% (2017) in Rizha, and insignificantly from 11.5% (2016) to 4.3% (2017) in Eduoma. Echinococcus multilocularis was the most prevalent species continually detected during the entire research period, while E. granulosus was rare and not detected in 2017. Echinococcus shiquicus prevalence was as high as E. multilocularis , although only detected in 2015 in Rizha. Unleashed dog feces were mainly collected in Rizha Village in 2015. Although 93.2% of owned dogs were leashed, and the monthly praziquantel dosing rate reached 97%, E. multilocularis infection could still be detected in 11.1% of owned dogs in 2017. Monthly deworming, leashing dogs 24h per day, and the avoidance of dogs feeding on livestock viscera are significant measures to prevent canine echinococcosis infection in owned dogs. Conclusion Carrying out a canine echinococcosis prevention and control program can significantly decrease the Echinococcus prevalence. The potential contact between leashed dogs and wild small mammals is still a risk to re-infect owned dogs. This study shows that the long term application of regular dog dosing in the vast remote echinococcosis endemic areas of west China is still challenging
Elliptic flow of meson and strange quark collectivity at RHIC
Based on A Multi-Phase Transport (AMPT) model, we have studied the elliptic
flow of mesons from reconstructed decay channel at
the top Relativistic Heavy Ion Collider energy at Brookhaven National
Laboratory. The dependences of on transverse momentum and
collision centrality are presented and the rescattering effect of mesons
in the hadronic phase is also investigated. The results show that experimental
measurement of for mesons can retain the early collision
information before decays and that the value obeys the
constituent quark number scaling which has been observed for other mesons and
baryons. Our study indicates that the mostly reflects partonic
level collectivity developed during the early stage of the nucleus-nucleus
collision and the strange and light up/down quarks have developed similar
angular anistropy properties at the hadronization.Comment: 5 pages and 5 figures; accepted by Physical Review
The development of building energy conservation in China: a review and critical assessment from the perspective of policy and institutional system
The rapid development of the building industry has become an important driving force for the fast growing energy use in China. The building industry contributed 26.4% of China’s GDP, and the building energy use accounted for 33% of the total energy use in China. Building energy conservation plays an important role in reaching the peak of carbon emissions before 2030, which was committed by the Chinese government in the Paris Agreement. Building energy conservation is a complex system. The guidance and support of government policies are one of the important issues. This research analyzed the institutional framework for building energy conservation in China. The roles and functions of each institution were critically reviewed. The policy system for building energy conservation was also analyzed, which included National Laws; Regulations of the State Council; Provisions of Ministries under the State Council; and National Standards, Plans and Programs. The suggestions for further improvements were drawn from the critical analysis such as defining clear and specific responsibility of management institutions, improving regulations and standard system, establishing the market leading mechanism, etc. This research draws an overall picture of the building energy conservation in China from the policy and institutional perspective. Findings provide a useful reference for increasing environmental performance in the building industry.Xueliang Yuan, Xiaoyu Zhang, Jiaxin Liang, Qingsong Wang and Jian Zu
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