1,126 research outputs found
Burkholderia ginsengiterrae sp. nov. and Burkholderia panaciterrae sp. nov., antagonistic bacteria against root rot pathogen Cylindrocarpon destructans, isolated from ginseng soil
Strain DCY85T and DCY85-1T, isolated from rhizosphere of ginseng, were rod-shaped, Gram-reaction-negative, strictly aerobic, catalase positive and oxidase negative. 16S rRNA gene sequence analysis revealed that strain DCY85T as well as DCY85-1T belonged to the genus Burkholderia and were closely related to Burkholderia fungorum KACC 12023T (98.1 and 98.0 % similarity, respectively). The major polar lipids of strain DCY85T and DCY85-1T were phosphatidylethanolamine, one unidentified aminolipid and two unidentified phospholipids. The major fatty acids of both strains are C16:0, C18:1ω7c and summed feature 3 (C16:1ω6c and/or C16:1ω7c). The predominant isoprenoid quinone of each strain DCY85T and DCY85-1T was ubiquinone (Q-8) and the G+C content of their genomic DNA was 66.0 and 59.4 mol%, respectively, which fulfill the characteristic range of the genus Burkholderia. The polyamine content of both DCY85T and DCY85-1T was putrescine. Although both DCY85T and DCY85-1T have highly similar 16S rRNA and identical RecA and gyrB sequences, they show differences in phenotypic and chemotaxonomic characteristics. DNA–DNA hybridization results proved the consideration of both strains as two different species. Based on the results from our polyphasic characterization, strain DCY85T and DCY85-1T are considered novel Burkholderia species for which the name Burkholderia ginsengiterrae sp. nov and Burkholderiapanaciterrae sp. nov are, respectively, proposed. An emended description of those strains is also proposed. DCY85T and DCY85-1T showed antagonistic activity against the common root rot pathogen of ginseng, Cylindrocarpon destructans. The proposed type strains are DCY85T (KCTC 42054T = JCM 19888T) and DCY85-1T (KCTC 42055T = JCM 19889T)
Resummation of heavy jet mass and comparison to LEP data
The heavy jet mass distribution in e+e- collisions is computed to
next-to-next-to-next-to leading logarithmic (NNNLL) and next-to-next-to leading
fixed order accuracy (NNLO). The singular terms predicted from the resummed
distribution are confirmed by the fixed order distributions allowing a precise
extraction of the unknown soft function coefficients. A number of quantitative
and qualitative comparisons of heavy jet mass and the related thrust
distribution are made. From fitting to ALEPH data, a value of alpha_s is
extracted, alpha_s(m_Z)=0.1220 +/- 0.0031, which is larger than, but not in
conflict with, the corresponding value for thrust. A weighted average of the
two produces alpha_s(m_Z) = 0.1193 +/- 0.0027, consistent with the world
average. A study of the non-perturbative corrections shows that the flat
direction observed for thrust between alpha_s and a simple non-perturbative
shape parameter is not lifted in combining with heavy jet mass. The Monte Carlo
treatment of hadronization gives qualitatively different results for thrust and
heavy jet mass, and we conclude that it cannot be trusted to add power
corrections to the event shape distributions at this accuracy. Whether a more
sophisticated effective field theory approach to power corrections can
reconcile the thrust and heavy jet mass distributions remains an open question.Comment: 33 pages, 14 figures. v2 added effect of lower numerical cutoff with
improved extraction of the soft function constants; power correction
discussion clarified. v3 small typos correcte
Non-global Structure of the O({\alpha}_s^2) Dijet Soft Function
High energy scattering processes involving jets generically involve matrix
elements of light- like Wilson lines, known as soft functions. These describe
the structure of soft contributions to observables and encode color and
kinematic correlations between jets. We compute the dijet soft function to
O({\alpha}_s^2) as a function of the two jet invariant masses, focusing on
terms not determined by its renormalization group evolution that have a
non-separable dependence on these masses. Our results include non-global single
and double logarithms, and analytic results for the full set of non-logarithmic
contributions as well. Using a recent result for the thrust constant, we
present the complete O({\alpha}_s^2) soft function for dijet production in both
position and momentum space.Comment: 55 pages, 8 figures. v2: extended discussion of double logs in the
hard regime. v3: minor typos corrected, version published in JHEP. v4: typos
in Eq. (3.33), (3.39), (3.43) corrected; this does not affect the main
result, numerical results, or conclusion
Adaptive twisting sliding mode control for quadrotor unmanned aerial vehicles
© 2017 IEEE. This work addresses the problem of robust attitude control of quadcopters. First, the mathematical model of the quadcopter is derived considering factors such as nonlinearity, external disturbances, uncertain dynamics and strong coupling. An adaptive twisting sliding mode control algorithm is then developed with the objective of controlling the quadcopter to track desired attitudes under various conditions. For this, the twisting sliding mode control law is modified with a proposed gain adaptation scheme to improve the control transient and tracking performance. Extensive simulation studies and comparisons with experimental data have been carried out for a Solo quadcopter. The results show that the proposed control scheme can achieve strong robustness against disturbances while is adaptable to parametric variations
Atresia of the Coronary Sinus Ostium With Anomalous Drainage Into Innominate Vein: Implications for CRT
Angle-Encoded Swarm Optimization for UAV Formation Path Planning
© 2018 IEEE. This paper presents a novel and feasible path planning technique for a group of unmanned aerial vehicles (DAVs) conducting surface inspection of infrastructure. The ultimate goal is to minimise the travel distance of DAVs while simultaneously avoid obstacles, and maintain altitude constraints as well as the shape of the UAV formation. A multiple-objective optimisation algorithm, called the Angle-encoded Particle Swarm Optimization (θ- PSO) algorithm, is proposed to accelerate the swarm convergence with angular velocity and position being used for the location of particles. The whole formation is modelled as a virtual rigid body and controlled to maintain a desired geometric shape among the paths created while the centroid of the group follows a pre-determined trajectory. Based on the testbed of 3DR Solo drones equipped with a proprietary Mission Planner, and the Internet-of- Things (loT) for multi-directional transmission and reception of data between the DAV s, extensive experiments have been conducted for triangular formation maintenance along a monorail bridge. The results obtained confirm the feasibility and effectiveness of the proposed approach
Automatic crack detection in built infrastructure using unmanned aerial vehicles
This paper addresses the problem of crack detection which is essential for health monitoring of built infrastructure. Our approach includes two stages, data collection using unmanned aerial vehicles (UAVs) and crack detection using histogram analysis. For the data collection, a 3D model of the structure is first created by using laser scanners. Based on the model, geometric properties are extracted to generate way points necessary for navigating the UAV to take images of the structure. Then, our next step is to stick together those obtained images from the overlapped field of view. The resulting image is then clustered by histogram analysis and peak detection. Potential cracks are finally identified by using locally adaptive thresholds. The whole process is automatically carried out so that the inspection time is significantly improved while safety hazards can be minimised. A prototypical system has been developed for evaluation and experimental results are included
Adaptive second-order sliding mode control of UAVs for civil applications
Quadcopters, as unmanned aerial vehicles (UAVs), have great potential in civil applications such as surveying, building monitoring, and infrastructure condition assessment. Quadcopters, however, are relatively sensitive to noises and disturbances so that their performance may be quickly downgraded in the case of inadequate control, system uncertainties and/or external disturbances. In this study, we deal with the quadrotor low-level control by proposing a robust scheme named the adaptive second-order quasi-continuous sliding mode control (adaptive 2-QCSM). The ultimate objective is for robust attitude control of the UAV in monitoring and inspection of built infrastructure. First, the mathematical model of the quadcopter is derived considering nonlinearity, strong coupling, uncertain dynamics and external disturbances. The control design includes the selection of the sliding manifold and the development of quasi-continuous second-order sliding mode controller with an adaptive gain. Stability of the overall control system is analysed by using a global Lyapunov function for convergence of both the sliding dynamics and adaptation scheme. Extensive simulations have been carried out for evaluation. Results show that the proposed controller can achieve robustness against disturbances or parameter variations and has better tracking performance in comparison with experimental responses of a UAV in a real-time monitoring task
Parton Fragmentation within an Identified Jet at NNLL
The fragmentation of a light parton i to a jet containing a light energetic
hadron h, where the momentum fraction of this hadron as well as the invariant
mass of the jet is measured, is described by "fragmenting jet functions". We
calculate the one-loop matching coefficients J_{ij} that relate the fragmenting
jet functions G_i^h to the standard, unpolarized fragmentation functions D_j^h
for quark and gluon jets. We perform this calculation using various IR
regulators and show explicitly how the IR divergences cancel in the matching.
We derive the relationship between the coefficients J_{ij} and the quark and
gluon jet functions. This provides a cross-check of our results. As an
application we study the process e+ e- to X pi+ on the Upsilon(4S) resonance
where we measure the momentum fraction of the pi+ and restrict to the dijet
limit by imposing a cut on thrust T. In our analysis we sum the logarithms of
tau=1-T in the cross section to next-to-next-to-leading-logarithmic accuracy
(NNLL). We find that including contributions up to NNLL (or NLO) can have a
large impact on extracting fragmentation functions from e+ e- to dijet + h.Comment: expanded introduction, typos fixed, journal versio
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