301 research outputs found
The Nonlinear Spatial Damping Rate in QGP
The derivative expansion method has been used to solve the semiclassical
kinetic equations of quark-gluon plasma (QGP). The nonlinear spatial damping
rate, the imaginary part of the wave vector, for the longitudinal secondary
color waves in the long wavelength limit has been calculated numerically.Comment: 11 page
Effects of Cor15a-IPT Gene Expression on Leaf Senescence in Transgenic Petunia x hybrida and Dendranthema x grandiflorum.
To prevent leaf senescence of young transplants or excised shoots during storage under dark and cold conditions, the cytokinin biosynthetic gene isopentenyl transferase (ipt) was placed under the control of a cold-inducible promoter cor15a from Arabidopsis thaliana and introduced into Petunia x hybrida \u27Marco Polo Odyssey\u27 and Dendranthema x grandiflorum (chrysanthemum) \u27Iridon\u27. Transgenic cor15a-ipt petunia and chrysanthemum plants and excised leaves remained green and healthy during prolonged dark storage (4 weeks at 25 degrees C) after an initial exposure to a brief cold-induction period (4 degrees C for 72 h). However, cor15a-ipt chrysanthemum plants and excised leaves that were not exposed to a cold-induction period, senesced under the same dark storage conditions. Regardless of cold-induction treatment, leaves and plants of non-transformed plants senesced under prolonged dark storage. Analysis of ipt expression indicated a marked increase in gene expression in intact transgenic plants as well as in isolated transgenic leaves exposed to a short cold-induction treatment prior to dark storage. These changes correlated with elevated concentrations of cytokinins in transgenic leaves after cold treatment. Cor15a-ipt transgenic plants showed a normal phenotype when grown at 25 degrees C
Numerical approximation of a phase-field surfactant model with fluid flow
Modelling interfacial dynamics with soluble surfactants in a multiphase
system is a challenging task. Here, we consider the numerical approximation of
a phase-field surfactant model with fluid flow. The nonlinearly coupled model
consists of two Cahn-Hilliard-type equations and incompressible Navier-Stokes
equation. With the introduction of two auxiliary variables, the governing
system is transformed into an equivalent form, which allows the nonlinear
potentials to be treated efficiently and semi-explicitly. By certain subtle
explicit-implicit treatments to stress and convective terms, we construct first
and second-order time marching schemes, which are extremely efficient and
easy-to-implement, for the transformed governing system. At each time step, the
schemes involve solving only a sequence of linear elliptic equations, and
computations of phase-field variables, velocity and pressure are fully
decoupled. We further establish a rigorous proof of unconditional energy
stability for the first-order scheme. Numerical results in both two and three
dimensions are obtained, which demonstrate that the proposed schemes are
accurate, efficient and unconditionally energy stable. Using our schemes, we
investigate the effect of surfactants on droplet deformation and collision
under a shear flow, where the increase of surfactant concentration can enhance
droplet deformation and inhibit droplet coalescence
Overexpression of Class III β-tubulin, Sox2, and nuclear Survivin is predictive of taxane resistance in patients with stage III ovarian epithelial cancer
Failed root canal treatment is best addressed primarily with the provision of repeat endodontic treatment with thorough irrigation under isolation. If a post is present in the root of the tooth it needs to be removed first. This paper is the second in a series of two which provide an overview of techniques for post removal. Specifically designed post removal devices and the removal of fibre posts are described. Post removal device techniques are illustrated with a series of clinical case figures
Numerical Fractional-Calculus Model for Two-Phase Flow in Fractured Media
Numerical simulation of two-phase flow in fractured porous media is an important topic in the subsurface flow, environmental problems, and petroleum reservoir engineering. The conventional model does not work well in many cases since it lacks the memory property of fracture media. In this paper, we develop a new numerical formulation with fractional time derivative for two-phase flow in fractured porous media. In the proposed formulation, the different fractional time derivatives are applied to fracture and matrix regions since they have different memory properties. We further develop a two-level time discrete method, which uses a large time step for the pressure and a small time step size for the saturation. The pressure equation is solved implicitly in each large time step, while the saturation is updated by an explicit fractional time scheme in each time substep. Finally, the numerical tests are carried out to demonstrate the effectiveness of the proposed numerical model
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