13,284 research outputs found
A Note on Symplectic, Multisymplectic Scheme in Finite Element Method
We find that with uniform mesh, the numerical schemes derived from finite
element method can keep a preserved symplectic structure in one-dimensional
case and a preserved multisymplectic structure in two-dimentional case in
certain discrete version respectively. These results are in fact the intrinsic
reason that the numerical experiments indicate that such finite element
algorithms are accurate in practice.Comment: 7 pages, 3 figure
A New Method for Fast Computation of Moments Based on 8-neighbor Chain CodeApplied to 2-D Objects Recognition
2D moment invariants have been successfully applied in pattern recognition tasks. The main difficulty of using moment invariants is the computational burden. To improve the algorithm of moments computation through an iterative method, an approach for fast computation of moments based on the 8-neighbor chain code is proposed in this paper. Then artificial neural networks are applied for 2D shape recognition with moment invariants. Compared with the method of polygonal approximation, this approach shows higher accuracy in shape representation and faster recognition speed in experiment
Transformation of Chinese as a Foreign Language Teachers’ Relationship with Their Students in the Australian Context
This study explores the transformation of teacher–student relationship between expatriate Chinese as a Foreign Language (CFL) teachers and their students situating in the Australian educational context. The disparity of tradition between the two educational cultures influences substantially on communication between teachers and students within classroom. To better understand how CFL teachers’ background educational culture may impact their interaction with Australian students, focus group discussion data were applied as the data collection method. Findings reveal that at the beginning of their teaching practice CFL teachers’ understanding of teacher–student relationship influenced by their background educational culture had major impact on their strategies in teacher–student interaction in class. However, with the progress of teaching and meantime influenced by the Australian local educational culture, their behaviors for dealing with teacher–student relationship in class changed. Basically, their ways of handling teacher–student relationship transformed from a more Eastern guanxi tendency to a more Western rapport tendency. This transformation did not occur automatically and easily; it was achieved by the CFL teachers’ struggles and tribulations in the process of interacting with their Australian students. In an era of CFL teacher shortage, it is hoped that this study would shed some light on CFL teacher education
Age as a risk factor for acute mountain sickness upon rapid ascent to 3,700 m among young adult Chinese men.
BackgroundThe aim of this study was to explore the relationship between age and acute mountain sickness (AMS) when subjects are exposed suddenly to high altitude.MethodsA total of 856 young adult men were recruited. Before and after acute altitude exposure, the Athens Insomnia Scale score (AISS) was used to evaluate the subjective sleep quality of subjects. AMS was assessed using the Lake Louise scoring system. Heart rate (HR) and arterial oxygen saturation (SaO2) were measured.ResultsResults showed that, at 500 m, AISS and insomnia prevalence were higher in older individuals. After acute exposure to altitude, the HR, AISS, and insomnia prevalence increased sharply, and the increase in older individuals was more marked. The opposite trend was observed for SaO2. At 3,700 m, the prevalence of AMS increased with age, as did severe AMS, and AMS symptoms (except gastrointestinal symptoms). Multivariate logistic regression analysis showed that age was a risk factor for AMS (adjusted odds ratio [OR] 1.07, 95% confidence interval [CI] 1.01-1.13, P<0.05), as well as AISS (adjusted OR 1.39, 95% CI 1.28-1.51, P<0.001).ConclusionThe present study is the first to demonstrate that older age is an independent risk factor for AMS upon rapid ascent to high altitude among young adult Chinese men, and pre-existing poor subjective sleep quality may be a contributor to increased AMS prevalence in older subjects
Confirming the 115.5-day periodicity in the X-ray light curve of ULX NGC 5408 X-1
The Swift/XRT light curve of the ultraluminous X-ray (ULX) source NGC 5408
X-1 was re-analyzed with two new numerical approaches, Weighted Wavelet
-transform (WWZ) and CLEANest, that are different from previous studies.
Both techniques detected a prominent periodicity with a time scale of
days, in excellent agreement with the detection of the same
periodicity first reported by Strohmayer (2009). Monte Carlo simulation was
employed to test the statisiticak confidence of the 115.5-day periodicity,
yielding a statistical significance of (or ). The robust
detection of the 115.5-day quasi-periodic oscillations (QPOs), if it is due to
the orbital motion of the binary, would infer a mass of a few thousand
for the central black hole, implying an intermediate-mass black hole
in NGC 5408 X-1.Comment: 6 pages, 2 figures, submitted to Research in Astronomy and
Astrophysics (RAA
Tris(piperazinediium) phosphatododecamolybo(V,VI)phosphate
The title compound, (C4H12N2)3[PMo12O40] or (H2pip)3[PMo12O40] (pip is piperazine), was prepared under hydrothermal conditions. The asymmetric unit contains one-sixth of a mixed-valent Mo(V,VI) pseudo-Keggin-type [PMo12O40]6− anion and half a piperazinediium cation, (H2pip)2+. The discrete Keggin-type [PMo12O40]6- anion has site symmetry and the three (H2pip)2+ cations each have site symmetry at the centres of the molecules. The central P atom is on special position , which is a roto-inversion position and generates the disorder of the PO4 tetrahedron. Furthermore, six doubly bridging oxide groups are also disordered with an occupancy factor of 0.5 for each O atom. The anions and cations are linked by an extensive network of intermolecular N—H⋯O and C—H⋯O hydrogen bonds
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