8,255 research outputs found
New transformation of Wigner operator in phase space quantum mechanics for the two-mode entangled case
As a natural extension of Fan's paper (arXiv: 0903.1769vl [quant-ph]) by
employing the formula of operators' Weyl ordering expansion and the bipartite
entangled state representation we find new two-fold complex integration
transformation about the Wigner operator (in its entangled form) in phase space
quantum mechanics and its inverse transformation. In this way, some operator
ordering problems can be solved and the contents of phase space quantum
mechanics can be enriched.Comment: 8 pages, 0 figure
Fresnel operator, squeezed state and Wigner function for Caldirola-Kanai Hamiltonian
Based on the technique of integration within an ordered product (IWOP) of
operators we introduce the Fresnel operator for converting Caldirola-Kanai
Hamiltonian into time-independent harmonic oscillator Hamiltonian. The Fresnel
operator with the parameters A,B,C,D corresponds to classical optical Fresnel
transformation, these parameters are the solution to a set of partial
differential equations set up in the above mentioned converting process. In
this way the exact wavefunction solution of the Schr\"odinger equation governed
by the Caldirola-Kanai Hamiltonian is obtained, which represents a squeezed
number state. The corresponding Wigner function is derived by virtue of the
Weyl ordered form of the Wigner operator and the order-invariance of Weyl
ordered operators under similar transformations. The method used here can be
suitable for solving Schr\"odinger equation of other time-dependent
oscillators.Comment: 6 pages, 2 figure
Ladybird: {Quasi-Monte Carlo} Sampling for Deep Implicit Field Based {3D} Reconstruction with Symmetry
Deep implicit field regression methods are effective for 3D reconstruction from single-view images. However, the impact of different sampling patterns on the reconstruction quality is not well-understood. In this work, we first study the effect of point set discrepancy on the network training. Based on Farthest Point Sampling algorithm, we propose a sampling scheme that theoretically encourages better generalization performance, and results in fast convergence for SGD-based optimization algorithms. Secondly, based on the reflective symmetry of an object, we propose a feature fusion method that alleviates issues due to self-occlusions which makes it difficult to utilize local image features. Our proposed system Ladybird is able to create high quality 3D object reconstructions from a single input image. We evaluate Ladybird on a large scale 3D dataset (ShapeNet) demonstrating highly competitive results in terms of Chamfer distance, Earth Mover's distance and Intersection Over Union (IoU)
Quantum tunneling time of a Bose-Einstein condensate traversing through a laser-induced potential barrier
We theoretically study the effect of atomic nonlinearity on the tunneling
time in the case of an atomic Bose-Einstein condensate (BEC) traversing the
laser-induced potential barrier. The atomic nonlinearity is controlled to
appear only in the region of the barrier by employing the Feshbach resonance
technique to tune interatomic interaction in the tunneling process. Numerical
simulation shows that the atomic nonlinear effect dramatically changes the
tunneling behavior of the BEC matter wave packet, and results in the violation
of Hartman effect and the occurrence of negative tunneling time.Comment: 4 pages, 5 figure
Effect of cyadox on growth and nutrient digestibility in weanling pigs
The effect of cyadox on growth and apparent digestibility of nutrients in weanling pigs was investigated. Cyadox (2-formylquinoxaline-N1,N4-dioxide cyanocetylhydrazone) is a derivative of quinoxaline-1, 4-dioxide, a growth promoting antimicrobial agent that is used in pig production. Seventy-five crossbred weanling barrows were randomly assigned to three treatments with five replicates per treatment. The three dietary treatments consisted of an unmedicated diet (control), a diet containing 100 mg/kg of cyadox and a diet containing 100 mg /kg of olaquindox. The body weight and feed consumption of the pigs were measured weekly for the 4-week experimental period. During week 4 a digestibility study was conducted, and faecal grab samples were collected for six days from each pen. The pigs fed cyadox had significantly higher average daily gains and improved feed conversion efficiencies compared to the control. Cyadox did not affect average daily feed intake. The apparent digestibility of dry matter, crude protein, ether extract, nitrogen free extract, calcium, phosphorus and gross energy was significantly increased in the cyadox-fed pigs above the control. Inclusion of cyadox significantly improved the apparent digestibility of iron, copper, zinc and manganese, and that of several essential and nonessential amino acids. It is suggested that the growth promoting effect of cyadox may be attributed to the improvement in the apparent digestibility of dietary nutrients.. Keywords: Cyadox; pig; average daily gain; feed conversion efficiency;digestibility; amino acids; mineral elements South African Journal of Animal Sciences Vol. 35 (2) 2005: pp.117-12
A possible disk mechanism for the 23d QPO in Mkn~501
Optically thin two-temperature accretion flows may be thermally and viscously
stable, but acoustically unstable. Here we propose that the O-mode instability
of a cooling-dominated optically thin two-temperature inner disk may explain
the 23-day quasi-periodic oscillation (QPO) period observed in the TeV and
X-ray light curves of Mkn~501 during its 1997 high state. In our model the
relativistic jet electrons Compton upscatter the disk soft X-ray photons to TeV
energies, so that the instability-driven X-ray periodicity will lead to a
corresponding quasi-periodicity in the TeV light curve and produce correlated
variability. We analyse the dependence of the instability-driven
quasi-periodicity on the mass (M) of the central black hole, the accretion rate
() and the viscous parameter () of the inner disk. We
show that in the case of Mkn~501 the first two parameters are constrained by
various observational results, so that for the instability occurring within a
two-temperature disk where , the quasi-period is expected to
lie within the range of 8 to 100 days, as indeed the case. In particular, for
the observed 23-day QPO period our model implies a viscosity coefficient
, a sub-Eddington accretion rate and a transition radius to the outer standard disk of , and predicts a period variation due to the
motion of the instability region.Comment: 18 pages, 1 figure, accepted by AP
Five Dimensions of School-Based Counseling Practice: Factor Analysis Identification Using the International Survey of School Counselors’ Activities
This article describes a factor analytic study designed to identify the underlying dimensions of school-based counseling practice that will be useful in describing cross-national differences in school-based counseling practice and in enabling comparative research on school-based counseling policy and effectiveness. Practicing school-based counselors (N = 2913) from 10 countries (China, Costa Rica, India, Kenya, South Korea, Malta, Nigeria, Turkey, the United States, and Venezuela) used the International Survey of School-Based Counseling Activities (ISSCA) to rate the centrality of 40 activities to the role of a school-based counselor. Factor analysis determined that five dimensions adequately described the school-based counselor role: Counseling Services; Advocacy and Systemic Improvement; Prevention Programs; Administrator Role; and Educational and Career Planning. Analysis of Bartlett Factor Score averages revealed that each country demonstrates a unique profile which reflects that country’s dominant mode of practice. This lead article describes these dimensions and the cross-national differences on these dimensions. Subsequent articles in this special issue describe country-specific results and explain factors that affect practice within each country
Differential responses of the rhizosphere microbiome structure and soil metabolites in tea (Camellia sinensis) upon application of cow manure
Background
The rhizosphere is the narrow zone of soil immediately surrounding the root, and it is a critical hotspot of microbial activity, strongly influencing the physiology and development of plants. For analyzing the relationship between the microbiome and metabolome in the rhizosphere of tea (Camellia sinensis) plants, the bacterial composition and its correlation to soil metabolites were investigated under three different fertilization treatments (unfertilized, urea, cow manure) in different growing seasons (spring, early and late summer).
Results
The bacterial phyla Proteobacteria, Bacteroidetes, Acidobacteria and Actinobacteria dominated the rhizosphere of tea plants regardless of the sampling time. These indicated that the compositional shift was associated with different fertilizer/manure treatments as well as the sampling time. However, the relative abundance of these enriched bacteria varied under the three different fertilizer regimes. Most of the enriched metabolic pathways stimulated by different fertilizer application were all related to sugars, amino acids fatty acids and alkaloids metabolism. Organic acids and fatty acids were potential metabolites mediating the plant-bacteria interaction in the rhizosphere. Bacteria in the genera Proteiniphilum, Fermentimonas and Pseudomonas in spring, Saccharimonadales and Gaiellales in early summer, Acidobacteriales and Gaiellales in late summer regulated relative contents of organic and fatty acids.
Conclusion
This study documents the profound changes to the rhizosphere microbiome and bacterially derived metabolites under different fertilizer regimes and provides a conceptual framework towards improving the performance of tea plantations
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