156 research outputs found

    Petrov-Galerkin Method for the Coupled Schrödinger-KdV Equation

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    Petrov-Galerkin method is used to derive a numerical scheme for the coupled Schrödinger-KdV (SKdV) equations, where we have used the cubic B-splines as a test functions and a linear B-splines as a trial functions. Product approximation technique is used to deal with the nonlinear terms. An implicit midpoint rule and the Runge-Kutta method of fourth-order (RK4) are used to discretize in time. A block nonlinear pentadiagonal system is obtained. We solve this system by the fixed point method. The resulting scheme has a fourth-order accuracy in space direction and second-order in time direction in case of the implicit midpoint rule and it is unconditionally stable by von Neumann method. Using the RK4 method the scheme will be linear and fourth-order in time and space directions, and it is also conditionally stable. The exact soliton solution and the conserved quantities are used to assess the accuracy and to show the robustness and the efficiency of the proposed schemes

    Dynamical Viscosity of Nucleating Bubbles

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    We study the viscosity corrections to the growth rate of nucleating bubbles in a first order phase transition in scalar field theory. We obtain the non-equilibrium equation of motion of the coordinate that describes small departures from the critical bubble and extract the growth rate consistently in weak coupling and in the thin wall limit. Viscosity effects arise from the interaction of this coordinate with the stable quantum and thermal fluctuations around a critical bubble. In the case of 1+1 dimensions we provide an estimate for the growth rate that depends on the details of the free energy functional. In 3+1 dimensions we recognize robust features that are a direct consequence of the thin wall approximation and give the leading viscosity corrections.These are long-wavelength hydrodynamic fluctuations that describe surface waves, quasi-Goldstone modes which are related to ripples on interfaces in phase ordered Ising-like systems. We discuss the applicability of our results to describe the growth rate of hadron bubbles in a quark-hadron first order transition.Comment: 40 pages, 4 figures, revtex, minor changes, to be published in Phys. Rev.

    Comparative genomics study reveals Red Sea Bacillus with characteristics associated with potential microbial cell factories (MCFs)

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    © 2019, The Author(s). Recent advancements in the use of microbial cells for scalable production of industrial enzymes encourage exploring new environments for efficient microbial cell factories (MCFs). Here, through a comparison study, ten newly sequenced Bacillus species, isolated from the Rabigh Harbor Lagoon on the Red Sea shoreline, were evaluated for their potential use as MCFs. Phylogenetic analysis of 40 representative genomes with phylogenetic relevance, including the ten Red Sea species, showed that the Red Sea species come from several colonization events and are not the result of a single colonization followed by speciation. Moreover, clustering reactions in reconstruct metabolic networks of these Bacillus species revealed that three metabolic clades do not fit the phylogenetic tree, a sign of convergent evolution of the metabolism of these species in response to special environmental adaptation. We further showed Red Sea strains Bacillus paralicheniformis (Bac48) and B. halosaccharovorans (Bac94) had twice as much secreted proteins than the model strain B. subtilis 168. Also, Bac94 was enriched with genes associated with the Tat and Sec protein secretion system and Bac48 has a hybrid PKS/NRPS cluster that is part of a horizontally transferred genomic region. These properties collectively hint towards the potential use of Red Sea Bacillus as efficient protein secreting microbial hosts, and that this characteristic of these strains may be a consequence of the unique ecological features of the isolation environment

    Nigella sativa supplementation Improves asthma control and biomarkers: a randomized, double-blind, placebo-controlled trial

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    Poor compliance with conventional asthma medications remains a major problem in achieving asthma control. Nigella sativa oil (NSO) is used traditionally for many inflammatory conditions such as asthma. We aimed to investigate the benefits of NSO supplementation on clinical and inflammatory parameters of asthma. NSO capsules 500 mg twice daily for 4 weeks were used as a supplementary treatment in a randomized, double-blind, placebo-controlled trial in asthmatics (clinicaltrials.gov: NCT02407262). The primary outcome was Asthma Control Test score. The secondary outcomes were pulmonary function test, blood eosinophils and total serum Immunoglobulin E. Between 1 June and 30 December 2015, 80 asthmatics were enrolled, with 40 patients in each treatment and placebo groups. After 4 weeks, ten patients had withdrawn from each group. Compared with placebo, NSO group showed a significant improvement in mean Asthma Control Test score 21.1 (standard deviation = 2.6) versus 19.6 (standard deviation = 3.7) (p = 0.044) and a significant reduction in blood eosinophils by −50 (−155 to −1) versus 15 (−60 to 87) cells/μL (p = 0.013). NSO improved forced expiratory volume in 1 second as percentage of predicted value by 4 (−1.25 to 8.75) versus 1 (−2 to 5) but non-significant (p = 0.170). This randomized, double-blind, placebo-controlled trial demonstrated that NSO supplementation improves asthma control with a trend in pulmonary function improvement. This was associated with a remarkable normalization of blood eosinophlia. Future studies should follow asthmatics for longer periods in a multicentre trial

    High-efficiency and air-stable P3HT-based polymer solar cells with a new non-fullerene acceptor

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    We thank BASF for partial financial support, as well as EPSRC Projects EP/G037515/1 and EP/M023532/1, EC FP7 Project SC2 (610115), EC FP7 Project ArtESun (604397), EC FP7 Project POLYMED (612538), Project Synthetic carbon allotropes project SFB 953 and the King Abdullah University of Science and Technology (KAUST)
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