8,149 research outputs found

    The effects of dog management on Echinococcus spp. prevalence in villages on the eastern Tibetan Plateau, China

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    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

    A Measurement-Driven Process Model For Managing Inconsistent Software Requirements

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    Inconsistency is a pervasive issue in software engineering. Both general rules of inconsistency management and special case-based approaches to handling inconsistency have recently been considered. In this paper, we present a process model for handling requirements inconsistency within the Viewpoints framework. In this process model, when an inconsistency among viewpoints is detected, a set of candidate proposals for handling inconsistency will be generated using techniques fromMulti-agent automated negotiations. The proposals are then prioritized using an integrated measurement of inconsistencies. The viewpoints involved in the inconsistency will then enter the negotiations by being presented with the candidate proposals and thus selecting an acceptable proposal based on the priorities associated with each candidate proposal. To facilitate usability, in our process, we assume that the natural language requirements statements are first translated into corresponding logical formulas using a translator software. Moreover, the candidate proposals for handling inconsistency are also translated back from formal logic into natural language before being presented for selection

    Segmentation, Reconstruction, and Analysis of Blood Thrombus Formation in 3D 2-Photon Microscopy Images

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    We study the problem of segmenting, reconstructing, and analyzing the structure growth of thrombi (clots) in blood vessels in vivo based on 2-photon microscopic image data. First, we develop an algorithm for segmenting clots in 3D microscopic images based on density-based clustering and methods for dealing with imaging artifacts. Next, we apply the union-of-balls (or alpha-shape) algorithm to reconstruct the boundary of clots in 3D. Finally, we perform experimental studies and analysis on the reconstructed clots and obtain quantitative data of thrombus growth and structures. We conduct experiments on laser-induced injuries in vessels of two types of mice (the wild type and the type with low levels of coagulation factor VII) and analyze and compare the developing clot structures based on their reconstructed clots from image data. The results we obtain are of biomedical significance. Our quantitative analysis of the clot composition leads to better understanding of the thrombus development, and is valuable to the modeling and verification of computational simulation of thrombogenesis

    Development of an expert system to assist in Resource Management

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    © 2014 IEEE. This paper aims to demonstrate an idea of utilizing Kohonen Maps as a tool to portray and study resource allocations when constructing an expert system to assist in Resource Management. The context of work encompasses resource allocation and management tasks related to design of courses, as well as, various teaching and learning projects. The key aspect is to show the design of an expert system for resource allocation with the use of Kohonen Maps as an alternative way to visualise the demand and availability of project resources

    Transverse Velocity Field Measurement in High-Resolution Solar Images Based on Deep Learning

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    To address the problem of the low accuracy of transverse velocity field measurements for small targets in high-resolution solar images, we proposed a novel velocity field measurement method for high-resolution solar images based on PWCNet. This method transforms the transverse velocity field measurements into an optical flow field prediction problem. We evaluated the performance of the proposed method using the Ha and TiO datasets obtained from New Vacuum Solar Telescope (NVST) observations. The experimental results show that our method effectively predicts the optical flow of small targets in images compared with several typical machine- and deep-learning methods. On the Ha dataset, the proposed method improves the image structure similarity from 0.9182 to 0.9587 and reduces the mean of residuals from 24.9931 to 15.2818; on the TiO dataset, the proposed method improves the image structure similarity from 0.9289 to 0.9628 and reduces the mean of residuals from 25.9908 to 17.0194. The optical flow predicted using the proposed method can provide accurate data for the atmospheric motion information of solar images. The code implementing the proposed method is available on https://github.com/lygmsy123/transverse-velocity-field-measurement.Comment: 14 pages, 10 figures, 4 tables. Accepted for publication in Research in Astronomy and Astrophysic

    Evidence for Two Gaps and Breakdown of the Uemura Plot in Ba0.6_{0.6}K0.4_{0.4}Fe2_2As2_2 Single Crystals

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    We report a detailed investigation on the lower critical field Hc1H_{c1} of the superconducting Ba0.6_{0.6}K0.4_{0.4}Fe2_2As2_2 (FeAs-122) single crystals. A pronounced kink is observed on the Hc1(T)H_{c1}(T) curve, which is attributed to the existence of two superconducting gaps. By fitting the data Hc1(T)H_{c1}(T) to the two-gap BCS model in full temperature region, a small gap of Δa(0)=2.0±0.3\Delta_a(0)=2.0\pm 0.3 meV and a large gap of Δb(0)=8.9±0.4\Delta_b(0)=8.9\pm 0.4 meV are obtained. The in-plane penetration depth λab(0)\lambda_{ab}(0) is estimated to be 105 nm corresponding to a rather large superfluid density, which points to the breakdown of the Uemura plot in FeAs-122 superconductors.Comment: 5 pages, 4 figure

    Structural study on hole-doped superconductors Pr1-xSrxFeAsO

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    The structural details in Pr1-xSrxFeAsO (1111) superconducting system are analyzed using data obtained from synchrotron X-ray diffraction and the structural parameters are carefully studied as the system is moving from non-superconducting to hole-doped superconducting with the Sr concentration. Superconductivity emerges when the Sr doping amount reaches 0.221. The linear increase of the lattice constants proves that Sr is successfully introduced into the system and its concentration can accurately be determined by the electron density analyses. The evolution of structural parameters with Sr concentration in Pr1-xSrxFeAsO and their comparison to other similar structural parameters of the related Fe-based superconductors suggest that the interlayer space between the conducting As-Fe-As layer and the insulating Pr-O-Pr layer is important for improving Tc in the hole-doped (1111) superconductors, which seems to be different from electron-doped systems.Comment: 17 pages, 7 figures, 1 tabl

    Higher-Order Band Topology in Twisted Moiré Superlattice

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    The two-dimensional (2D) twisted bilayer materials with van der Waals coupling have ignited great research interests, paving a new way to explore the emergent quantum phenomena by twist degree of freedom. Generally, with the decreasing of twist angle, the enhanced interlayer coupling will gradually flatten the low-energy bands and isolate them by two high-energy gaps at zero and full filling, respectively. Although the correlation and topological physics in the low-energy flat bands have been intensively studied, little information is available for these two emerging gaps. In this Letter, we predict a 2D second-order topological insulator (SOTI) for twisted bilayer graphene and twisted bilayer boron nitride in both zero and full filling gaps. Employing a tight-binding Hamiltonian based on first-principles calculations, three unique fingerprints of 2D SOTI are identified, that is, nonzero bulk topological index, gapped topological edge state, and in-gap topological corner state. Most remarkably, the 2D SOTI exists in a wide range of commensurate twist angles, which is robust to microscopic structure disorder and twist center, greatly facilitating the possible experimental measurement. Our results not only extend the higher-order band topology to massless and massive twisted moiré superlattice, but also demonstrate the importance of high-energy bands for fully understanding the nontrivial electronics
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