2,880 research outputs found
On-line monitoring of vertical long wavelength track irregularities using bogie pitch rate
Long wavelength track irregularities are the key factors which influence vehicle stability and comfort. An on-line monitoring method is proposed to detect the vertical long wavelength track irregularities based on bogie pitch rate. Firstly, the principle of on-line monitoring method based on axle-box acceleration or bogie pitch rate was presented. Secondly, to process bogie pitch rate, a mix-filtering approach which contains time-space domain transformation, double integration, baseline correction and RLS (Recursive Least Squares) adaptive compensation filter was proposed. Thirdly, a coupling dynamics model of vertical vehicle-track interactions was developed to obtain bogie pitch rate. The obtained bogie pitch rate was then filtered with the signal processing approach. When the processed result compares with the actual irregularities, the SD (Standard Deviation) is 0.327 mm and the NMSE (Normalized Mean Square Error) is –9.1495. The experimental result shows that the proposed on-line monitoring method based on bogie pitch rate and signal processing approach are capable of monitoring the long wavelength track irregularities accurately and effectively
The global geometrical property of jet events in high-energy nuclear collisions
We present the first theoretical study of medium modifications of the global
geometrical pattern, i.e., transverse sphericity () distribution of
jet events with parton energy loss in relativistic heavy-ion collisions. In our
investigation, POWHEG+PYTHIA is employed to make an accurate description of
transverse sphericity in the p+p baseline, which combines the next-to-leading
order (NLO) pQCD calculations with the matched parton shower (PS). The Linear
Boltzmann Transport (LBT) model of the parton energy loss is implemented to
simulate the in-medium evolution of jets. We calculate the event normalized
transverse sphericity distribution in central Pb+Pb collisions at the LHC, and
give its medium modifications. An enhancement of transverse sphericity
distribution at small region but a suppression at large
region are observed in A+A collisions as compared to their p+p references,
which indicates that in overall the geometry of jet events in Pb+Pb becomes
more pencil-like. We demonstrate that for events with 2 jets in the final-state
of heavy-ion collisions, the jet quenching makes the geometry more sphere-like
with medium-induced gluon radiation. However, for events with ~jets,
parton energy loss in the QCD medium leads to the events more pencil-like due
to jet number reduction, where less energetic jets may lose their energies and
then fall off the jet selection kinematic cut. These two effects offset each
other and in the end result in more jetty events in heavy-ion collisions
relative to that in p+p.Comment: 9 pages, 9 figure
Four-state rock-paper-scissors games on constrained Newman-Watts networks
We study the cyclic dominance of three species in two-dimensional constrained
Newman-Watts networks with a four-state variant of the rock-paper-scissors
game. By limiting the maximal connection distance in Newman-Watts
networks with the long-rang connection probability , we depict more
realistically the stochastic interactions among species within ecosystems. When
we fix mobility and vary the value of or , the Monte Carlo
simulations show that the spiral waves grow in size, and the system becomes
unstable and biodiversity is lost with increasing or . These
results are similar to recent results of Reichenbach \textit{et al.} [Nature
(London) \textbf{448}, 1046 (2007)], in which they increase the mobility only
without including long-range interactions. We compared extinctions with or
without long-range connections and computed spatial correlation functions and
correlation length. We conclude that long-range connections could improve the
mobility of species, drastically changing their crossover to extinction and
making the system more unstable.Comment: 6 pages, 7 figure
Orbital density wave induced by electron-lattice coupling in orthorhombic iron pnictides
In this paper we explore the magnetic and orbital properties closely related
to a tetragonal-orthorhombic structural phase transition in iron pnictides
based on both two- and five-orbital Hubbard models. The electron-lattice
coupling, which interplays with electronic interaction, is self-consistently
treated. Our results reveal that the orbital polarization stabilizes the spin
density wave (SDW) order in both tetragonal and orthorhombic phases. However,
the ferro-orbital density wave (F-ODW) only occurs in the orthorhombic phase
rather than in the tetragonal one. Magnetic moments of Fe are small in the
intermediate Coulomb interaction region for the striped antiferromangnetic
phase in the realistic five orbital model. The anisotropic Fermi surface in the
SDW/ODW orthorhombic phase is well in agreement with the recent angle-resolved
photoemission spectroscopy experiments. These results suggest a scenario that
the magnetic phase transition is driven by the ODW order mainly arising from
the electron-lattice coupling.Comment: 21 pages, 10 figure
Chloroquinone Inhibits Cell Proliferation and Induces Apoptosis in Nasopharyngeal Carcinoma Cell Lines
Purpose: To demonstrate the role of chloroquinone (CQ) in inducing apoptosis in HONE-1 and HNE-1, nasopharyngeal carcinoma (NPC) cell lines.Methods: Water-soluble tetrazolium salt (WST)-1 assay was used for the determination of cell proliferation while an inverted microscope was employed for the analysis of alterations in the morphology of the cells.Results: CQ treatment led to a significant reduction in the rate of cell proliferation in NPC cells after 48 h. In HONE-1 and HNE-1 cell lines viability was reduced to 89 and 82 %, respectively on treatment with 10 μΜ concentration of CQ without affecting normal human skin keratinocyte cell line, K38. The expression of Ki67, a marker for proliferation as well as proliferating cell nuclear antigen (PCNA), decreased in the CQ-treated NPC cells. Morphological examination of NPC cells revealed cell apoptosis on treatment with CQ after 48 h. Treatment of NPC cells with CQ induced activation of caspases and DNA was damaged which further confirmed CQ mediated induction of apoptosis. The level of apoptotic cells in CQ treated and untreated control HONE-1 cell cultures was 53.67 and 3.78 %, respectively (p < 0.05). In addition, CQ treatment decreased reactive oxygen species (ROS) generation in NPC cells.Conclusion: CQ inhibits cell proliferation of NPC cells by inducing apoptosis via DNA damage, and may be of therapeutic use for the treatment of NPC. However, this requires clinical investigation to ascertain its therapeutic potential.Keywords: Chloroquinone, Caspases, Apoptosis, Nuclear antigen, Nasopharyngeal carcinom
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