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Sample records for variable-coefficient korteweg-de vries

  1. Equivalence groupoid of a class of variable coefficient Korteweg-de Vries equations

    Science.gov (United States)

    Vaneeva, Olena; Pošta, Severin

    2017-10-01

    We classify the admissible transformations in a class of variable coefficient Korteweg-de Vries equations. As a result, a full description of the structure of the equivalence groupoid of the class is given. The class under study is partitioned into six disjoint normalized subclasses. The widest possible equivalence group for each subclass is found which appears to be generalized extended in five cases. Ways for improvement of transformational properties of the subclasses are proposed using gaugings of arbitrary elements and mapping between classes. The group classification of one of the subclasses is carried out as an illustrative example.

  2. BÄCKLUND Transformation and Analytic Solutions for a Generalized Variable-Coefficient Modified Korteweg-De Vries Model from Fluid Dynamics and Plasmas

    Science.gov (United States)

    Sun, Fu-Wei; Gao, Yi-Tian; Zhang, Chun-Yi; Xu, Xiao-Ge

    We investigate a generalized variable-coefficient modified Korteweg-de Vries model with perturbed factor and external force (vc-GmKdV) describing fluid dynamics and space plasmas. In this paper, we propose an extended variable-coefficient balancing-act method (Evc-BAM), which is concise and straightforward, to obtain the generalized analytic solutions including solitary wave solution of the vc-GmKdV model with symbolic computation. Meanwhile, using the Evc-BAM, we obtain an auto-Bäcklund transformation for the vc-GmKdV model on the relevant constraint conditions of the coefficient functions. Using the given auto-Bäcklund transformation, the solutions of special equations for the vc-GmKdV model are also obtained as the variable-coefficient Korteweg-de Vries (vc-KdV) equation, the generalized KdV equation with perturbed factor and external force (GKdV), the variable-coefficient modified Korteweg-de Vries (vc-mKdV) equation, and the variable-coefficient cylindrical modified Korteweg-de Vries (vc-cmKdV) equation, respectively.

  3. Numerical inverse scattering for the Korteweg-de Vries and modified Korteweg-de Vries equations

    Science.gov (United States)

    Trogdon, Thomas; Olver, Sheehan; Deconinck, Bernard

    2012-06-01

    Recent advances in the numerical solution of Riemann-Hilbert problems allow for the implementation of a Cauchy initial-value problem solver for the Korteweg-de Vries equation (KdV) and the defocusing modified Korteweg-de Vries equation (mKdV), without any boundary approximation. Borrowing ideas from the method of nonlinear steepest descent, this method is demonstrated to be asymptotically accurate. The method is straightforward for the case of defocusing mKdV due to the lack of poles in the Riemann-Hilbert problem and the boundedness properties of the reflection coefficient. Solving KdV requires the introduction of poles in the Riemann-Hilbert problem and more complicated deformations. The introduction of a new deformation for KdV allows for the stable asymptotic computation of the solution in the entire spacial and temporal plane. KdV and mKdV are dispersive equations, and this method can fully capture the dispersion with spectral accuracy. Thus, this method can be used as a benchmarking tool for determining the effectiveness of future numerical methods designed to capture dispersion. This method can easily be adapted to other integrable equations with Riemann-Hilbert formulations, such as the nonlinear Schrödinger equation.

  4. A Discrete Negative Order Potential Korteweg-de Vries Equation

    Science.gov (United States)

    Zhao, Song-lin; Sun, Ying-ying

    2016-12-01

    We investigate a discrete negative order potential Korteweg-de Vries (npKdV) equation via the generalised Cauchy matrix approach. Solutions more than multisoliton solutions of this equation are derived by solving the determining equation set. We also show the semidiscrete equation and continuous equation together with their exact solutions by considering the continuum limits.

  5. The Time-Fractional Coupled-Korteweg-de-Vries Equations

    Directory of Open Access Journals (Sweden)

    Abdon Atangana

    2013-01-01

    Full Text Available We put into practice a relatively new analytical technique, the homotopy decomposition method, for solving the nonlinear fractional coupled-Korteweg-de-Vries equations. Numerical solutions are given, and some properties exhibit reasonable dependence on the fractional-order derivatives’ values. The fractional derivatives are described in the Caputo sense. The reliability of HDM and the reduction in computations give HDM a wider applicability. In addition, the calculations involved in HDM are very simple and straightforward. It is demonstrated that HDM is a powerful and efficient tool for FPDEs. It was also demonstrated that HDM is more efficient than the adomian decomposition method (ADM, variational iteration method (VIM, homotopy analysis method (HAM, and homotopy perturbation method (HPM.

  6. Renormalization in the cauchy problem for the Korteweg-de Vries equation

    Science.gov (United States)

    Zakharov, S. V.

    2013-05-01

    We consider the Cauchy problem for the Korteweg-de Vries equation with a small parameter at the highest derivative and a large gradient of the initial function. We construct an asymptotic solution of this problem by the renormalization method.

  7. Renormalized asymptotic solutions of the Burgers equation and the Korteweg-de Vries equation

    OpenAIRE

    Zakharov, Sergei V.

    2015-01-01

    The Cauchy problem for the Burgers equation and the Korteweg-de Vries equation is considered. Uniform renormalized asymptotic solutions are constructed in cases of a large initial gradient and a perturbed initial weak discontinuity.

  8. On exact traveling-wave solutions for local fractional Korteweg-de Vries equation

    Science.gov (United States)

    Yang, Xiao-Jun; Tenreiro Machado, J. A.; Baleanu, Dumitru; Cattani, Carlo

    2016-08-01

    This paper investigates the Korteweg-de Vries equation within the scope of the local fractional derivative formulation. The exact traveling wave solutions of non-differentiable type with the generalized functions defined on Cantor sets are analyzed. The results for the non-differentiable solutions when fractal dimension is 1 are also discussed. It is shown that the exact solutions for the local fractional Korteweg-de Vries equation characterize the fractal wave on shallow water surfaces.

  9. On exact traveling-wave solutions for local fractional Korteweg-de Vries equation.

    Science.gov (United States)

    Yang, Xiao-Jun; Tenreiro Machado, J A; Baleanu, Dumitru; Cattani, Carlo

    2016-08-01

    This paper investigates the Korteweg-de Vries equation within the scope of the local fractional derivative formulation. The exact traveling wave solutions of non-differentiable type with the generalized functions defined on Cantor sets are analyzed. The results for the non-differentiable solutions when fractal dimension is 1 are also discussed. It is shown that the exact solutions for the local fractional Korteweg-de Vries equation characterize the fractal wave on shallow water surfaces.

  10. Self-similar planar curves related to modified Korteweg-de Vries equation

    Science.gov (United States)

    Perelman, G.; Vega, L.

    We exhibit a time reversible geometric flow of planar curves which can develop singularities in finite time within the uniform topology. The example is based on the construction of selfsimilar solutions of modified Korteweg-de Vries equation of a given (small) mean.

  11. Invariant measures generated by higher conservation laws for the Korteweg-de Vries equations

    Science.gov (United States)

    Zhidkov, P. E.

    1996-06-01

    The well-posedness of the Cauchy problem that is periodic with respect to the spatial variable is proved for the Korteweg-de Vries equation. For dynamical systems generated by this equation on appropriate phase spaces the invariance of the Borel measures associated with the higher conservation laws is proved.

  12. On the low regularity of the modified Korteweg-de Vries equation with a dissipative term

    Science.gov (United States)

    Chen, Wengu; Li, Junfeng

    We consider a dissipative version of the modified Korteweg-de Vries equation u+u-u+(=0. We prove global well-posedness results on the associated Cauchy problem in the Sobolev spaces H(R) for s>-1/4 while for s<-1/2 we prove some ill-posedness issues.

  13. Gain of regularity for a Korteweg - de Vries - Kawahara type equation

    Directory of Open Access Journals (Sweden)

    Octavio Paulo Vera Villagran

    2004-05-01

    Full Text Available We study the existence of local and global solutions, and the gain of regularity for the initial value problem associated to the Korteweg - de Vries - Kawahara (KdVK equation perturbed by a dispersive term which appears in several fluids dynamics problems. The study of gain of regularity is motivated by the results obtained by Craig, Kappeler and Strauss [8].

  14. New exact solutions of fractional Hirota-Satsuma coupled Korteweg-de Vries equations

    Directory of Open Access Journals (Sweden)

    Cui Lian-Xiang

    2015-01-01

    Full Text Available An improved extended tg-function method, which combines the fractional complex transform and the extended tanh-function method, is applied to find exact solutions of non-linear fractional partial differential equations. Generalized Hirota-Satsuma coupled Korteweg-de Vries equations are used as an example to elucidate the effectiveness and simplicity of the method.

  15. The Laplace series solution for local fractional Korteweg-de Vries equation

    Directory of Open Access Journals (Sweden)

    Ye Shan-Shan

    2016-01-01

    Full Text Available In this paper, we consider a new application of the local fractional Laplace series expansion method to handle the local fractional Korteweg-de Vries equation. The obtained solution with non-differentiable type shows that the technology is accurate and efficient.

  16. The Stochastic Korteweg-de Vries Equation in L2( R)

    Science.gov (United States)

    Printems, Jacques

    1999-04-01

    We present here two results of global existence and uniqueness of the Cauchy problem concerning the Korteweg-de Vries equation forced by a random term of white noise type in the functional framework of weighted spaces onL2(R). This work is motivated by both physical experiments where a forced generation of weakly nonlinear waves by localized disturbances was observed [1, 15] and a result of uniqueness in weighted space in the homogeneous case [8, 14].

  17. Global well-posedness and inviscid limit for the Korteweg-de Vries-Burgers equation

    Science.gov (United States)

    Guo, Zihua; Wang, Baoxiang

    Considering the Cauchy problem for the Korteweg-de Vries-Burgers equation u+u+ɛ|2αu+(u)=0, u(0)=ϕ, where 0s), and uniformly globally well-posed in H ( s>-3/4) for all ɛ∈(0,1]. Moreover, we prove that for any T>0, its solution converges in C([0,T];H) to that of the KdV equation if ɛ tends to 0.

  18. Information-entropic analysis of Korteweg-de Vries solitons in the quark-gluon plasma

    Science.gov (United States)

    Goncalves da Silva, A.; da Rocha, Roldão

    2017-11-01

    Solitary waves propagation of baryonic density perturbations, ruled by the Korteweg-de Vries equation in a mean-field quark-gluon plasma model, are investigated from the point of view of the theory of information. A recently proposed continuous logarithmic measure of information, called configurational entropy, is used to derive the soliton width, defining the pulse, for which the informational content of the soliton spatial profile is more compressed, in the Shannon's sense.

  19. Complete integrability of two-coupled discrete modified Korteweg-de Vries equations

    Energy Technology Data Exchange (ETDEWEB)

    Sahadevan, R; Balakrishnan, S [Ramanujan Institute for Advanced Study in Mathematics, University of Madras, Chepauk, Chennai 600 005, Tamilnadu (India)], E-mail: ramajayamsaha@yahoo.co.in, E-mail: s_krishnan1982@yahoo.co.in

    2009-10-16

    We report that two-coupled discrete modified Korteweg-de Vries equations (2-dmKdV) governed by nonlinear partial differential-difference equations are completely integrable. We derive Lax matrices for 2-dmKdV and also show that it admits a sequence of generalized (non-point) symmetries and polynomial conserved densities establishing its complete integrability. Also exact solutions of it expressible in terms of Hyperbolic and Jacobian elliptic functions have been derived.

  20. The Sylvester equation and the elliptic Korteweg-de Vries system

    Science.gov (United States)

    Sun, Ying-ying; Zhang, Da-jun; Nijhoff, Frank W.

    2017-03-01

    The elliptic potential Korteweg-de Vries lattice system is a multi-component extension of the lattice potential Korteweg-de Vries equation, whose soliton solutions are associated with an elliptic Cauchy kernel (i.e., a Cauchy kernel on the torus). In this paper we generalize the class of solutions by allowing the spectral parameter to be a full matrix obeying a matrix version of the equation of the elliptic curve, and for the Cauchy matrix to be a solution of a Sylvester type matrix equation subject to this matrix elliptic curve equation. The construction involves solving the matrix elliptic curve equation by using Toeplitz matrix techniques, and analysing the solution of the Sylvester equation in terms of Jordan normal forms. Furthermore, we consider the continuum limit system associated with the elliptic potential Korteweg-de Vries system, and analyse the dynamics of the soliton solutions, which reveals some new features of the elliptic system in comparison to the non-elliptic case.

  1. On the origin of the Korteweg-de Vries equation

    NARCIS (Netherlands)

    de Jager, E.M.; Baierl, R.

    2011-01-01

    A. Honorary colloquium "Rudolf Gorenflo. Fluids from a fractional viewpoint". B. Hans Gebelein's turbulence from a stochastic viewpoint, waves of Korteweg and de Vries, cellular diffusion, etc. (A. Festkolloquium ``Rudolf Gorenflo. Fluide aus fraktionaler Sicht". B. Hans Gebeleins Turbulenz aus

  2. Reformulasi dari Solusi 3-soliton untuk Persamaan Korteweg-de Vries

    OpenAIRE

    mustikaningsih, Dian; Sutimin, Sutimin

    2002-01-01

    The solution of 3-soliton for Korteweg-de Vries (KdV) equation can be obtained by the Hirota Method. The reformulation of the 3-soliton solution was represented as the superposition of the solution of each individual soliton. Moreover, the asymptotic form of 3-soliton solution was obtained by limiting of the t parameter. The phase shift of each individual soliton are analysed in detail based its asymptotic form. The results of the analysis shown that the first soliton always have a phase shi...

  3. Inversion of the linearized Korteweg-de Vries equation at the multi-soliton solutions

    CERN Document Server

    Haragus-Courcelle, M

    1998-01-01

    Uniform estimates for the decay structure of the $n$-soliton solution of the Korteweg-deVries equation are obtained. The KdV equation, linearized at the $n$-soliton solution is investigated in a class $\\WW$ consisting of sums of travelling waves plus an exponentially decaying residual term. An analog of the kernel of the time-independent equation is proposed, leading to solvability conditions on the inhomogeneous term. Estimates on the inversion of the linearized KdV equation at the $n$-soliton are obtained.

  4. Two-soliton interaction in the framework of modified Korteweg - de Vries equation

    CERN Document Server

    Pelinovsky, E N

    2014-01-01

    Interaction of two solitons of the different polarities in the framework of modified Korteweg-de Vries (mKdV) equation is studied. Three types of soliton interaction are considered: exchange and overtaking for solitons of the same polarity, and absorb-emit for solitons of different polarity. Features of soliton interaction are studied in details. Since the interaction of solitons is an elementary act of soliton turbulence, the moments of the wave field up to fourth are studied, which are usually considered in the turbulence theory. It is shown that in the case of interaction of solitons of the same polarity the third and fourth moments of the wave field, which determine the coefficients of skewness and kurtosis in the theory of turbulence, are reduced, while in the case of interaction of solitons of different polarity these moments are increased. The results are compared with the estimations for the two-soliton interaction in the framework of the Korteweg - de Vries (KdV) equation.

  5. Asymptotic behaviour as t\\to \\infty of the solutions of the generalized Korteweg-de Vries equation

    Science.gov (United States)

    Naumkin, P. I.; Shishmarev, I. A.

    1996-06-01

    Asymptotic formulae representing for large time the solution of the Cauchy problem are obtained for the generalized Korteweg-de Vries equation with non-linear term to an integer power greater than three. The error terms are estimated. The method is based on the perturbation theory with respect to a parameter characterizing the smallness of the initial data.

  6. The dual modified Korteweg-de Vries-Fokas-Qiao equation: Geometry and local analysis

    Science.gov (United States)

    Bies, Piotr Michał; Górka, Przemysław; Reyes, Enrique G.

    2012-07-01

    We study a bi-hamiltonian equation with cubic nonlinearity shown to appear in the theory of water waves by Fokas, derived by Qiao using the two-dimensional Euler equation, and also known to arise as the dual of the modified Korteweg-de Vries equation thanks to work by Fokas, Fuchssteiner, Olver, and Rosenau. We present a quadratic pseudo-potential, we compute infinite sequences of local and nonlocal conservation laws, and we construct an infinite-dimensional Lie algebra of symmetries which contains a semi-direct sum of the sl(2,{R})-loop algebra and the centerless Virasoro algebra. As an application we prove a theorem on the existence of smooth solutions, and we construct some explicit examples. Moreover, we consider the Cauchy problem and we prove existence and uniqueness of weak solutions in the Sobolev space H^{q+2}({R}), q > 1/2.

  7. Korteweg-de Vries description of Helmholtz-Kerr dark solitons

    Energy Technology Data Exchange (ETDEWEB)

    Christian, J M [Joule Physics Laboratory, School of Computing, Science and Engineering, Institute for Materials Research, University of Salford, Salford M5 4WT (United Kingdom) ; McDonald, G S [Joule Physics Laboratory, School of Computing, Science and Engineering, Institute for Materials Research, University of Salford, Salford M5 4WT (United Kingdom) ; Chamorro-Posada, P [Departmento de TeorIa de la Senal y Comunicaciones e IngenierIa Telematica, Universidad de Valladolid, ETSI Telecomunicacion, Campus Miguel Delibes s/n, 47011 Valladolid (Spain)

    2006-12-15

    A wide variety of different physical systems can be described by a relatively small set of universal equations. For example, small-amplitude nonlinear Schroedinger dark solitons can be described by a Korteweg-de Vries (KdV) equation. Reductive perturbation theory, based on linear boosts and Gallilean transformations, is often employed to establish connections to and between such universal equations. Here, a novel analytical approach reveals that the evolution of small-amplitude Helmholtz-Kerr dark solitons is also governed by a KdV equation. This broadens the class of nonlinear systems that are known to possess KdV soliton solutions, and provides a framework for perturbative analyses when propagation angles are not negligibly small. The derivation of this KdV equation involves an element that appears new to weakly nonlinear analyses, since transformations are required to preserve the rotational symmetry inherent to Helmholtz-type equations.

  8. A Korteweg-de Vries description of dark solitons in polariton superfluids

    Science.gov (United States)

    Carretero-González, R.; Cuevas-Maraver, J.; Frantzeskakis, D. J.; Horikis, T. P.; Kevrekidis, P. G.; Rodrigues, A. S.

    2017-12-01

    We study the dynamics of dark solitons in an incoherently pumped exciton-polariton condensate by means of a system composed of a generalized open-dissipative Gross-Pitaevskii equation for the polaritons' wavefunction and a rate equation for the exciton reservoir density. Considering a perturbative regime of sufficiently small reservoir excitations, we use the reductive perturbation method, to reduce the system to a Korteweg-de Vries (KdV) equation with linear loss. This model is used to describe the analytical form and the dynamics of dark solitons. We show that the polariton field supports decaying dark soliton solutions with a decay rate determined analytically in the weak pumping regime. We also find that the dark soliton evolution is accompanied by a shelf, whose dynamics follows qualitatively the effective KdV picture.

  9. Solution of the pulse width modulation problem using orthogonal polynomials and Korteweg-de Vries equations.

    Science.gov (United States)

    Chudnovsky, D V; Chudnovsky, G V

    1999-10-26

    The mathematical underpinning of the pulse width modulation (PWM) technique lies in the attempt to represent "accurately" harmonic waveforms using only square forms of a fixed height. The accuracy can be measured using many norms, but the quality of the approximation of the analog signal (a harmonic form) by a digital one (simple pulses of a fixed high voltage level) requires the elimination of high order harmonics in the error term. The most important practical problem is in "accurate" reproduction of sine-wave using the same number of pulses as the number of high harmonics eliminated. We describe in this paper a complete solution of the PWM problem using Pade approximations, orthogonal polynomials, and solitons. The main result of the paper is the characterization of discrete pulses answering the general PWM problem in terms of the manifold of all rational solutions to Korteweg-de Vries equations.

  10. On the Cauchy problem for the Korteweg-de Vries equation with steplike finite-gap initial data: I. Schwartz-type perturbations

    Science.gov (United States)

    Egorova, Iryna; Grunert, Katrin; Teschl, Gerald

    2009-06-01

    We solve the Cauchy problem for the Korteweg-de Vries equation with initial conditions which are steplike Schwartz-type perturbations of finite-gap potentials under the assumption that the respective spectral bands either coincide or are disjoint.

  11. Stability of a traveling-wave solution to the Cauchy problem for the Korteweg-de Vries-Burgers equation

    Science.gov (United States)

    Kazeykina, A. V.

    2010-04-01

    The asymptotic behavior of the solution to the Cauchy problem for the Korteweg-de Vries-Burgers equation u t + ( f( u)) x + au xxx - bu xx = 0 as t → ∞ is analyzed. Sufficient conditions for the existence and local stability of a traveling-wave solution known in the case of f( u) = u 2 are extended to the case of an arbitrary sufficiently smooth convex function f( u).

  12. Critical densities for Korteweg-de Vries-like acoustic solitons in multi-ion plasmas

    Science.gov (United States)

    Verheest, Frank

    2015-12-01

    > A generic proof has been given that, for the acoustic mode with the highest velocity in a plasma comprising a number of fluid species and one kind of inertialess electrons, even though there can be critical densities (making the coefficient of the quadratic nonlinearity in a Korteweg-de Vries equation vanish), no supercritical densities exist (requiring the simultaneous annulment of both the quadratic and cubic nonlinearities in a reductive perturbation treatment). Similar conclusions hold upon expansion of the corresponding Sagdeev pseudopotential treatment. When there is only one (hot) electron species, the highest-velocity mode is an ion-acoustic one, but if there is an additional cool electron species, with its inertia taken into account, the highest-velocity mode is an electron-acoustic mode in a two-temperature plasma. The cool fluid species can have various polytropic pressure-density relations, including adiabatic and/or isothermal variations, whereas the hot inertialess electrons are modelled by extensions of the usual Boltzmann description that include non-thermal effects through Cairns, kappa or Tsallis distributions. Together, in this way quite a number of plasma models are covered. Unfortunately, there seems to be no equivalent generic statement for the slow modes, so that these have to be studied on a case-by-case basis, which for models with more than three species is far from straightforward, given the parameter ranges to be discussed.

  13. Perturbation series for the double cnoidal wave of the Korteweg-de Vries equation

    Science.gov (United States)

    Boyd, John P.

    1984-12-01

    By means of the theorems proved earlier by the author, the problem of the double cnoidal wave of the Korteweg-de Vries equation is reduced to four algebraic equations in four unknowns. Two of the unknowns are the nonlinear phase speeds c1 and c2. Another is a physically irrelevant integration constant. The fourth unknown is the off-diagonal element of the symmetric, 2×2 theta matrix, which in turn gives the explicit coefficients of the Riemann theta function. The double cnoidal wave u(x,t) is then obtained by taking the second x-derivative of the logarithm of the theta function. Two separate forms of these four nonlinear ``residual'' equations are given. One is obtained from the Fourier series of the theta function and is useful for small wave amplitude. The other is based on the Gaussian series of the theta function and is highly efficient in the large amplitude regime where the double cnoidal wave is the sum of two solitary waves. Both sets of residual equations can be solved via perturbation theory and results are given to fourth order in the Fourier case and second order in the Gaussian case. The Gaussian-based perturbation series has the remarkable property that it converges more and more rapidly as the wave amplitude increases; the zeroth-order solution is the familiar double solitary wave. Numerical comparisons show that the two complementary perturbation series give accurate results in all the important regions of parameter space. (The ``unimportant'' regions are those in which the double cnoidal wave is an ordinary cnoidal wave subject to a very weak perturbation.) This is turn implies that even for moderate wave amplitude where the nonlinear interactions are not weak, and yet the solitary wave peaks are not well separated, at least to the eye, it is still qualitatively legitimate to describe the double cnoidal wave as either the sum of two sine waves or of two solitary waves of different heights.

  14. Energy invariant for shallow-water waves and the Korteweg-de Vries equation: Doubts about the invariance of energy.

    Science.gov (United States)

    Karczewska, Anna; Rozmej, Piotr; Infeld, Eryk

    2015-11-01

    It is well known that the Korteweg-de Vries (KdV) equation has an infinite set of conserved quantities. The first three are often considered to represent mass, momentum, and energy. Here we try to answer the question of how this comes about and also how these KdV quantities relate to those of the Euler shallow-water equations. Here Luke's Lagrangian is helpful. We also consider higher-order extensions of KdV. Though in general not integrable, in some sense they are almost so within the accuracy of the expansion.

  15. Analytical study of exact solutions of the nonlinear Korteweg-de Vries equation with space-time fractional derivatives

    Science.gov (United States)

    Liu, Jiangen; Zhang, Yufeng

    2018-01-01

    This paper gives an analytical study of dynamic behavior of the exact solutions of nonlinear Korteweg-de Vries equation with space-time local fractional derivatives. By using the improved (G‧ G )-expansion method, the explicit traveling wave solutions including periodic solutions, dark soliton solutions, soliton solutions and soliton-like solutions, are obtained for the first time. They can better help us further understand the physical phenomena and provide a strong basis. Meanwhile, some solutions are presented through 3D-graphs.

  16. Travelling wave solutions of two-dimensional Korteweg-de Vries-Burgers and Kadomtsev-Petviashvili equations

    Energy Technology Data Exchange (ETDEWEB)

    Estevez, P G [Departamento de Fisica Fundamental, Area de Fisica Teorica, Universidad de Salamanca, 37008 Salamanca (Spain); Kuru, S [Departamento de Fisica Teorica, Atomica y Optica, Universidad de Valladolid, 47071 Valladolid (Spain); Negro, J [Departamento de Fisica Teorica, Atomica y Optica, Universidad de Valladolid, 47071 Valladolid (Spain); Nieto, L M [Departamento de Fisica Teorica, Atomica y Optica, Universidad de Valladolid, 47071 Valladolid (Spain)

    2006-09-15

    The travelling wave solutions of the two-dimensional Korteweg-de Vries-Burgers and Kadomtsev-Petviashvili equations are studied from two complementary points of view. The first one is an adaptation of the factorization technique that provides particular as well as general solutions. The second one applies the Painleve analysis to both equations, throwing light on some aspects of the first method and giving an explanation to some restriction on the coefficients, as well as the relation between factorizations and integrals of motion.

  17. Application of the heat-balance and refined integral methods to the Korteweg-de Vries equation

    Directory of Open Access Journals (Sweden)

    Myers Timothy G.

    2009-01-01

    Full Text Available In this paper we consider approximate travelling wave solutions to the Korteweg-de Vries equation. The heat-balance integral method is first applied to the problem, using two different quartic approximating functions, and then the refined integral method is investigated. We examine two types of solution, chosen by matching the wave speed to that of the exact solution and by imposing the same area. The first set of solutions is generally better with an error that is fixed in time. The second set of solutions has an error that grows with time. This is shown to be due to slight discrepancies in the wave speed.

  18. Solitary wave of the Korteweg-de Vries equation based on lattice Boltzmann model with three conservation laws

    Science.gov (United States)

    Wang, Huimin

    2017-01-01

    In this paper, a new lattice Boltzmann model for the Korteweg-de Vries (KdV) equation is proposed. By using the Chapman-Enskog expansion and the multi-scale time expansion, a series of partial differential equations in different time scales and several higher- order moments of equilibrium distribution functions are obtained. In order to make the scheme obey the three conservation laws of the KdV equation, two equilibrium distribution functions are used and a correlation between the first conservation law and the second conservation law is constructed. In numerical examples, the numerical results of the KdV equation obtained by this scheme are compared with those results obtained by the previous lattice Boltzmann model. Numerical experiments demonstrate this scheme can be used to reduce the truncation error of the lattice Boltzmann scheme and preserve the three conservation laws.

  19. CRE Solvability, Nonlocal Symmetry and Exact Interaction Solutions of the Fifth-Order Modified Korteweg-de Vries Equation

    Science.gov (United States)

    Cheng, Wen-Guang; Qiu, De-Qin; Yu, Bo

    2017-06-01

    This paper is concerned with the fifth-order modified Korteweg-de Vries (fmKdV) equation. It is proved that the fmKdV equation is consistent Riccati expansion (CRE) solvable. Three special form of soliton-cnoidal wave interaction solutions are discussed analytically and shown graphically. Furthermore, based on the consistent tanh expansion (CTE) method, the nonlocal symmetry related to the consistent tanh expansion (CTE) is investigated, we also give the relationship between this kind of nonlocal symmetry and the residual symmetry which can be obtained with the truncated Painlevé method. We further study the spectral function symmetry and derive the Lax pair of the fmKdV equation. The residual symmetry can be localized to the Lie point symmetry of an enlarged system and the corresponding finite transformation group is computed. Supported by National Natural Science Foundation of China under Grant No. 11505090, and Research Award Foundation for Outstanding Young Scientists of Shandong Province under Grant No. BS2015SF009

  20. Discrete singular convolution for the generalized variable-coefficient ...

    African Journals Online (AJOL)

    Numerical solutions of the generalized variable-coefficient Korteweg-de Vries equation are obtained using a discrete singular convolution and a fourth order singly diagonally implicit Runge-Kutta method for space and time discretisation, respectively. The theoretical convergence of the proposed method is rigorously ...

  1. The radius of convergence and the well-posedness of the Painlevé expansions of the Korteweg - de Vries equation

    Science.gov (United States)

    Joshi, Nalini; Srinivasan, Gopala K.

    1997-01-01

    In this paper we obtain explicit lower bounds for the radius of convergence of the Painlevé expansions of the Korteweg - de Vries equation around a movable singularity manifold 0951-7715/10/1/005/img1 in terms of the sup norms of the arbitrary functions involved. We use this estimate to prove the well-posedness of the singular Cauchy problem on 0951-7715/10/1/005/img1 in the form of continuous dependence of the meromorphic solution on the arbitrary data.

  2. Solitons of the coupled Schrödinger-Korteweg-de Vries system with arbitrary strengths of the nonlinearity and dispersion

    Science.gov (United States)

    Gromov, Evgeny; Malomed, Boris

    2017-11-01

    New two-component soliton solutions of the coupled high-frequency (HF)—low-frequency (LF) system, based on Schrödinger-Korteweg-de Vries (KdV) system with the Zakharov's coupling, are obtained for arbitrary relative strengths of the nonlinearity and dispersion in the LF component. The complex HF field is governed by the linear Schrödinger equation with a potential generated by the real LF component, which, in turn, is governed by the KdV equation including the ponderomotive coupling term, representing the feedback of the HF field onto the LF component. First, we study the evolution of pulse-shaped pulses by means of direct simulations. In the case when the dispersion of the LF component is weak in comparison to its nonlinearity, the input gives rise to several solitons in which the HF component is much broader than its LF counterpart. In the opposite case, the system creates a single soliton with approximately equal widths of both components. Collisions between stable solitons are studied too, with a conclusion that the collisions are inelastic, with a greater soliton getting still stronger, and the smaller one suffering further attenuation. Robust intrinsic modes are excited in the colliding solitons. A new family of approximate analytical two-component soliton solutions with two free parameters is found for an arbitrary relative strength of the nonlinearity and dispersion of the LF component, assuming weak feedback of the HF field onto the LF component. Further, a one-parameter (non-generic) family of exact bright-soliton solutions, with mutually proportional HF and LF components, is produced too. Intrinsic dynamics of the two-component solitons, induced by a shift of their HF component against the LF one, is also studied, by means of numerical simulations, demonstrating excitation of a robust intrinsic mode. In addition to the above-mentioned results for LF-dominated two-component solitons, which always run in one (positive) velocities, we produce HF

  3. Effect of trapped electron on the dust ion acoustic waves in dusty plasma using time fractional modified Korteweg-de Vries equation

    Science.gov (United States)

    Nazari-Golshan, A.; Nourazar, S. S.

    2013-10-01

    The time fractional modified Korteweg-de Vries (TFMKdV) equation is solved to study the nonlinear propagation of small but finite amplitude dust ion-acoustic (DIA) solitary waves in un-magnetized dusty plasma with trapped electrons. The plasma is composed of a cold ion fluid, stationary dust grains, and hot electrons obeying a trapped electron distribution. The TFMKdV equation is derived by using the semi-inverse and Agrawal's methods and then solved by the Laplace Adomian decomposition method. Our results show that the amplitude of the DIA solitary waves increases with the increase of time fractional order β, the wave velocity v0, and the population of the background free electrons λ. However, it is vice-versa for the deviation from isothermality parameter b, which is in agreement with the result obtained previously.

  4. Complex Korteweg-de Vries equation and Nonlinear dust-acoustic waves in a magnetoplasma with a pair of trapped ions

    CERN Document Server

    Misra, A P

    2015-01-01

    The nonlinear propagation of dust-acoustic (DA) waves in a magnetized dusty plasma with a pair of trapped ions is investigated. Starting from a set of hydrodynamic equations for massive dust fluids as well as kinetic Vlasov equations for ions, and applying the reductive perturbation technique, a Korteweg-de Vries (KdV)-like equation with a complex coefficient of nonlinearity is derived, which governs the evolution of small-amplitude DA waves in plasmas. The complex coefficient arises due to vortex-like distributions of both positive and negative ions. An analytical as well as numerical solution of the KdV equation are obtained and analyzed with the effects of external magnetic field, the dust pressure as well as different mass and temperatures of positive and negative ions.

  5. Initial-boundary value problems of the coupled modified Korteweg-de Vries equation on the half-line via the Fokas method

    Science.gov (United States)

    Tian, Shou-Fu

    2017-09-01

    In this paper, we implement the Fokas method in order to study initial-boundary value problems of the coupled modified Korteweg-de Vries equation formulated on the half-line, with Lax pairs involving 3× 3 matrices. This equation can be considered as a generalization of the modified KdV equation. We show that the solution \\{ p(x, t), q(x, t)\\} can be written in terms of the solution of a 3× 3 Riemann-Hilbert problem. The relevant jump matrices are explicitly expressed in terms of the matrix-value spectral functions s(k) and S(k) , which are respectively determined by the initial values and boundary values at x=0 . Finally, the associated Dirichlet to Neumann map of the equation is analyzed in detail. Some of these boundary values are unknown; however, using the fact that these specific functions satisfy a certain global relation, the unknown boundary values can be expressed in terms of the given initial and boundary data.

  6. Determination of the measure of size (amplitude) of perturbation and its role in the process of enforcing discrete Korteweg-de Vries solitons to modified Korteweg-de Vries solitons as means of continuum hypothesis in a multi-component dusty plasma

    Science.gov (United States)

    Kalita, B. C.; Das, S.; Bhattacharjee, D.

    2017-10-01

    The role of the order of perturbation required for establishing modified Korteweg-de Vries (mKdV) solitons and determining the corresponding measure of the size (amplitude) of perturbation ɛ in multi-component dusty plasma is investigated for the first time. Various amplitudes of mKdV solitons at critical density σc based on the respective measure of the size of perturbation generated by the corresponding number of dust charges Zd for some values of ion streaming vi0 are presented in Tables in this new pursuit. Many characteristic results of mKdV solitons connecting the totality of the newly established parameters, namely, initial ion streaming vi0, dust charge number Zd, measure of the size of perturbation ɛ, and non-thermal parameter β , are also reported. Further, a new range of non-thermal parameters β occurring in Cairns distribution is also determined in the presence of electrons with quantum effects for this dusty plasma.

  7. Modulated elliptic wave and asymptotic solitons in a shock problem to the modified Korteweg-de Vries equation

    Science.gov (United States)

    Kotlyarov, Vladimir; Minakov, Alexander

    2015-07-01

    We study the long-time asymptotic behavior of the Cauchy problem for the modified Korteweg—de Vries equation with an initial function of the step type. This function rapidly tends to zero as x\\to +∞ and to some positive constant c as x\\to -∞ . In 1989 Khruslov and Kotlyarov have found (Khruslov and Kotlyarov 1989 Inverse Problems 5 1075-88) that for a large time the solution breaks up into a train of asymptotic solitons located in the domain 4{c}2t-{C}N{ln}t\\lt x≤slant 4{c}2t ({C}N is a constant). The number N of these solitons grows unboundedly as t\\to ∞ . In 2010 Kotlyarov and Minakov have studied temporary asymptotics of the solution of the Cauchy problem on the whole line (Kotlyarov and Minakov 2010 J. Math. Phys. 51 093506) and have found that in the domain -6{c}2t\\lt x\\lt 4{c}2t this solution is described by a modulated elliptic wave. We consider here the modulated elliptic wave in the domain 4{c}2t-{C}N{ln}t\\lt x\\lt 4{c}2t. Our main result shows that the modulated elliptic wave also breaks up into solitons, which are similar to the asymptotic solitons in Khruslov and Kotlyarov (1989 Inverse Problems 5 1075-88), but differ from them in phase. It means that the modulated elliptic wave does not represent the asymptotics of the solution in the domain 4{c}2t-{C}N{ln}t\\lt x\\lt 4{c}2t. The correct asymptotic behavior of the solution is given by the train of asymptotic solitons given in Khruslov and Kotlyarov (1989 Inverse Problems 5 1075-88). However, in the asymptotic regime as t\\to ∞ in the region 4{c}2t-\\displaystyle \\frac{N+1/4}{c}{ln}t\\lt x\\lt 4{c}2t-\\displaystyle \\frac{N-3/4}{c}{ln}t we can watch precisely a pair of solitons with numbers N. One of them is the asymptotic soliton while the other soliton is generated from the elliptic wave. Their phases become closer to each other for a large N, i.e. these solitons are also close to each other. This result gives the answer on a very important question about matching of the asymptotic

  8. Evolution of randomly perturbed Korteweg-de Vries solitons

    DEFF Research Database (Denmark)

    Abdullaev, F. Kh.; Darmanyan, S. A.; Djumaev, M. R.

    1995-01-01

    that the distribution function has non-Gaussian form and that the most probable and the mean value of the soliton amplitudes are distinct. The analytical results agrees well with the results of the numerical simulations of the KdV equation with random initial conditions. The results obtained for the KdV equation...

  9. Acoustic Scattering and the Extended Korteweg-de Vries hierarchy

    CERN Document Server

    Beals, R; Szmigielski, J

    1998-01-01

    The acoustic scattering operator on the real line is mapped to a Schrödinger operator under the Liouville transformation. The potentials in the image are characterized precisely in terms of their scattering data, and the inverse transformation is obtained as a simple, linear quadrature. An existence theorem for the associated Harry Dym flows is proved, using the scattering method. The scattering problem associated with the Camassa-Holm flows on the real line is solved explicitly for a special case, which is used to reduce a general class of such problems to scattering problems on finite intervals.

  10. Fractal complex transform technology for fractal Kkorteweg-de Vries equation within a local fractional derivative

    Directory of Open Access Journals (Sweden)

    Xu Jinze

    2016-01-01

    Full Text Available In this paper, we present the fractal complex transform via a local fractional derivative. The traveling wave solutions for the fractal Korteweg-de Vries equations within local fractional derivative are obtained based on the special functions defined on Cantor sets. The technology is a powerful tool for solving the local fractional non-linear partial differential equations.

  11. Blowup of solutions of a Korteweg-de Vries-type equation

    Science.gov (United States)

    Yushkov, E. V.

    2012-07-01

    We investigate the nonlinear third-order differential equation (uxx - u)t + u xxx + uux = 0 describing the processes in semiconductors with a strong spatial dispersion. We study the problem of the existence of global solutions and obtain sufficient conditions for the absence of global solutions for some initial boundary value problems corresponding to this equation. We consider examples of solution blowup for initial boundary value and Cauchy problems. We use the Mitidieri-Pokhozhaev nonlinear capacity method.

  12. Computing the Solutions of the Combined Korteweg-de Vries Equation by Turing Machines

    Directory of Open Access Journals (Sweden)

    Dianchen Lu

    2010-06-01

    Full Text Available In this paper, we study the computability of the initial value problem of the Combined KdV equation. It is shown that, for any integer s>2, the nonlinear solution operator which maps an initial condition data to the solution of the Combined KdV equation can be computed by a Turing machine.

  13. Conservation Laws for a Generalized Coupled Korteweg-de Vries System

    Directory of Open Access Journals (Sweden)

    Daniel Mpho Nkwanazana

    2013-01-01

    Full Text Available We construct conservation laws for a generalized coupled KdV system, which is a third-order system of nonlinear partial differential equations. We employ Noether's approach to derive the conservation laws. Since the system does not have a Lagrangian, we make use of the transformation u=Ux, v=Vx and convert the system to a fourth-order system in U, V. This new system has a Lagrangian, and so the Noether approach can now be used to obtain conservation laws. Finally, the conservation laws are expressed in the u, v variables, and they constitute the conservation laws for the third-order generalized coupled KdV system. Some local and infinitely many nonlocal conserved quantities are found.

  14. Efficiency of High-Order Accurate Difference Schemes for the Korteweg-de Vries Equation

    Directory of Open Access Journals (Sweden)

    Kanyuta Poochinapan

    2014-01-01

    Full Text Available Two numerical models to obtain the solution of the KdV equation are proposed. Numerical tools, compact fourth-order and standard fourth-order finite difference techniques, are applied to the KdV equation. The fundamental conservative properties of the equation are preserved by the finite difference methods. Linear stability analysis of two methods is presented by the Von Neumann analysis. The new methods give second- and fourth-order accuracy in time and space, respectively. The numerical experiments show that the proposed methods improve the accuracy of the solution significantly.

  15. Exact Solutions of a High-Order Nonlinear Wave Equation of Korteweg-de Vries Type under Newly Solvable Conditions

    Directory of Open Access Journals (Sweden)

    Weiguo Rui

    2014-01-01

    Full Text Available By using the integral bifurcation method together with factoring technique, we study a water wave model, a high-order nonlinear wave equation of KdV type under some newly solvable conditions. Based on our previous research works, some exact traveling wave solutions such as broken-soliton solutions, periodic wave solutions of blow-up type, smooth solitary wave solutions, and nonsmooth peakon solutions within more extensive parameter ranges are obtained. In particular, a series of smooth solitary wave solutions and nonsmooth peakon solutions are obtained. In order to show the properties of these exact solutions visually, we plot the graphs of some representative traveling wave solutions.

  16. Solving Variable Coefficient Fourth-Order Parabolic Equation by ...

    African Journals Online (AJOL)

    In this paper, a Modified initial guess Variational Iteration Method (MigVIM) is used to solve a non-homogeneous variable coefficient fourth order parabolic partial differential equations. The new method shows rapid convergence to the exact solution.

  17. Variable-coefficient nonisospectral Toda lattice hierarchy and its ...

    Indian Academy of Sciences (India)

    Abstract. In this paper, a hierarchy of nonisospectral equations with variable coefficients is derived from the compatibility condition of Toda spectral problem and its time evolution. In order to solve the derived Toda lattice hierarchy, the inverse scattering transformation is utilized. As a result, new and more general exact ...

  18. Solving Second-Order Differential Equations with Variable Coefficients

    Science.gov (United States)

    Wilmer, A., III; Costa, G. B.

    2008-01-01

    A method is developed in which an analytical solution is obtained for certain classes of second-order differential equations with variable coefficients. By the use of transformations and by repeated iterated integration, a desired solution is obtained. This alternative method represents a different way to acquire a solution from classic power…

  19. Multipoint problem with for factorized parabolic operator with variable coefficients

    Directory of Open Access Journals (Sweden)

    I. R. Tymkiv

    2011-12-01

    Full Text Available The correctness of the problem with multipoints conditions with respect time-variable and conditions of the Dirichlet by Petrovski linear parabolic equation with variable coefficients in a limited cylindrical domen. The conditions of existence and uniqueness of the classical solution of the problem are established. The metrical theorems on evalution from below of small denominators of the problem are proved.

  20. Author Details

    African Journals Online (AJOL)

    Maré, Eben. Vol 40, No 2 (2017) - Articles Discrete singular convolution for the generalized variable-coefficient Korteweg-de Vries equation. Abstract. ISSN: 1607-3606. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms and ...

  1. Positive solutions for fractional differential equations with variable coefficients

    Directory of Open Access Journals (Sweden)

    Yi Chen

    2012-05-01

    Full Text Available In this article, we study the existence of the positive solutions for a class of differential equations of fractional order with variable coefficients. The equation of this type plays an important role in the description and modeling of control systems, such as $PD^{mu}$-controller. The differential operator is taken in the Riemann-Liouville sense. Our analysis relies on the Leggett-Williams fixed point theorem.

  2. Memory boundary feedback stabilization for Schrodinger equations with variable coefficients

    Directory of Open Access Journals (Sweden)

    Abdesselam Nawel

    2017-05-01

    Full Text Available First we consider the boundary stabilization of Schrodinger equations with constant coefficient memory feedback. This is done by using Riemannian geometry methods and the multipliers technique. Then we explore the stabilization limits of Schrodinger equations whose elliptical part has a variable coefficient. We established the exponential decay of solutions using the multipliers techniques. The introduction of dissipative boundary conditions of memory type allowed us to obtain an accurate estimate on the uniform rate of decay of the energy for Schrodinger equations.

  3. Solution of heat equation with variable coefficient using derive

    CSIR Research Space (South Africa)

    Lebelo, RS

    2008-09-01

    Full Text Available -reviewed Conference Proceedings, 22 – 26 September  2008  - 129 - Solution of heat equation with variable coefficient using derive RS Lebeloα, I Fedotov and M Shatalovβ Department of Mathematics and Statistics Tshwane University of Technology Pretoria... of algebraic and transcedental equations. Buffelspoort TIME2008 Peer-reviewed Confe- rence Proceedings, 22-26 September, South Africa, ISBN 978-3-901769- 82-5, pp. 162 – 173. [5] R.S. Lebelo (2008). Approximating solutions of partial differential equations...

  4. Analytical model of reactive transport processes with spatially variable coefficients.

    Science.gov (United States)

    Simpson, Matthew J; Morrow, Liam C

    2015-05-01

    Analytical solutions of partial differential equation (PDE) models describing reactive transport phenomena in saturated porous media are often used as screening tools to provide insight into contaminant fate and transport processes. While many practical modelling scenarios involve spatially variable coefficients, such as spatially variable flow velocity, v(x), or spatially variable decay rate, k(x), most analytical models deal with constant coefficients. Here we present a framework for constructing exact solutions of PDE models of reactive transport. Our approach is relevant for advection-dominant problems, and is based on a regular perturbation technique. We present a description of the solution technique for a range of one-dimensional scenarios involving constant and variable coefficients, and we show that the solutions compare well with numerical approximations. Our general approach applies to a range of initial conditions and various forms of v(x) and k(x). Instead of simply documenting specific solutions for particular cases, we present a symbolic worksheet, as supplementary material, which enables the solution to be evaluated for different choices of the initial condition, v(x) and k(x). We also discuss how the technique generalizes to apply to models of coupled multispecies reactive transport as well as higher dimensional problems.

  5. Local energy decay for linear wave equations with variable coefficients

    Science.gov (United States)

    Ikehata, Ryo

    2005-06-01

    A uniform local energy decay result is derived to the linear wave equation with spatial variable coefficients. We deal with this equation in an exterior domain with a star-shaped complement. Our advantage is that we do not assume any compactness of the support on the initial data, and its proof is quite simple. This generalizes a previous famous result due to Morawetz [The decay of solutions of the exterior initial-boundary value problem for the wave equation, Comm. Pure Appl. Math. 14 (1961) 561-568]. In order to prove local energy decay, we mainly apply two types of ideas due to Ikehata-Matsuyama [L2-behaviour of solutions to the linear heat and wave equations in exterior domains, Sci. Math. Japon. 55 (2002) 33-42] and Todorova-Yordanov [Critical exponent for a nonlinear wave equation with damping, J. Differential Equations 174 (2001) 464-489].

  6. Benjamin–Bona–Mahony Equation with Variable Coefficients: Conservation Laws

    Directory of Open Access Journals (Sweden)

    Ben Muatjetjeja

    2014-12-01

    Full Text Available This paper aims to construct conservation laws for a Benjamin–Bona–Mahony equation with variable coefficients, which is a third-order partial differential equation. This equation does not have a Lagrangian and so we transform it to a fourth-order partial differential equation, which has a Lagrangian. The Noether approach is then employed to construct the conservation laws. It so happens that the derived conserved quantities fail to satisfy the divergence criterion and so one needs to make adjustments to the derived conserved quantities in order to satisfy the divergence condition. The conservation laws are then expressed in the original variable. Finally, a conservation law is used to obtain exact solution of a special case of the Benjamin–Bona–Mahony equation.

  7. Finite-amplitude wave propagation in a stratified fluid of variable depth

    CERN Document Server

    Didenkulova, I; Pelinovsky, E; Kurkina, O; Rodin, A; Pankratov, A; Naumov, A; Giniyatullin, A

    2012-01-01

    Variable-coefficient Korteweg - de Vries equation is applied to describe the interfacial wave transformation in two-layer fluid of variable depth. The soliton dynamics in this fluid is studied. The solitary wave breaks in two transient points. One of them is the point when two-layer fluid transforms to the on-layer flow. The second one is the point where layer thickness are equaled. The soliton amplitude dependence on the thickness of lower layer is found.

  8. Energy decay of a variable-coefficient wave equation with nonlinear time-dependent localized damping

    Directory of Open Access Journals (Sweden)

    Jieqiong Wu

    2015-09-01

    Full Text Available We study the energy decay for the Cauchy problem of the wave equation with nonlinear time-dependent and space-dependent damping. The damping is localized in a bounded domain and near infinity, and the principal part of the wave equation has a variable-coefficient. We apply the multiplier method for variable-coefficient equations, and obtain an energy decay that depends on the property of the coefficient of the damping term.

  9. Painlevé analysis and some solutions of variable coefficient Benny ...

    Indian Academy of Sciences (India)

    researchers have shown considerable interest in studying variable coefficient nonlinear equations. Various methods like inverse scattering transformation (IST) [1,2], ... loped a highly algorithmic method known as the Lie point symmetry method (group .... where ϵ is the group parameter, which leaves the system invariant.

  10. Study of Nonhomogeneous Equations with Variable Coefficients Describing Washing Machines Vibration

    Directory of Open Access Journals (Sweden)

    Sergey N. Alekhin

    2012-05-01

    Full Text Available Earlier in a slightly intertwined system of differential equations describing the dynamics of the random vibrations of the drum type washing machine suspended unit was fixed. This article studies the general case of nonhomogeneous equations with variable coefficients describing washing machines vibration.

  11. Extending the Constant Coefficient Solution Technique to Variable Coefficient Ordinary Differential Equations

    Science.gov (United States)

    Mohammed, Ahmed; Zeleke, Aklilu

    2015-01-01

    We introduce a class of second-order ordinary differential equations (ODEs) with variable coefficients whose closed-form solutions can be obtained by the same method used to solve ODEs with constant coefficients. General solutions for the homogeneous case are discussed.

  12. Time-dependent exact solutions for Rosenau-Hyman equations with variable coefficients

    Science.gov (United States)

    Souza, Wescley Luiz de; Silva, Érica de Mello

    2015-03-01

    In this work we study Rosenau-Hyman-like equations that were obtained by imposing the Lie point symmetry algebra of standard KdV to a general K (m, n) equation with variable coefficients. We present time-dependent exact solutions for suited choices of parameters m and n, including the similarity solution related to rarefaction shock wave phenomena.

  13. FUNCTIONAL SIMILARITY METHOD APPLICABLE AS A SOLUTION TO SOME LINEAR DIFFERENTIAL EQUATIONS WITH VARIABLE COEFFICIENTS

    Directory of Open Access Journals (Sweden)

    Vardanjan Gumedin Surenovich

    2012-10-01

    Full Text Available The functional similarity method applicable for the simulation of various physical processes is considered in the proposed paper. A solution to some linear differential equations with variable coefficients is provided. The aforementioned equations are widely used as part of solutions to problems of mechanics of deformable solid bodies.

  14. Symmetry Classification and Exact Solutions of a Variable Coefficient Space-Time Fractional Potential Burgers’ Equation

    Directory of Open Access Journals (Sweden)

    Manoj Gaur

    2016-01-01

    Full Text Available We investigate the symmetry properties of a variable coefficient space-time fractional potential Burgers’ equation. Fractional Lie symmetries and corresponding infinitesimal generators are obtained. With the help of the infinitesimal generators, some group invariant solutions are deduced. Further, some exact solutions of fractional potential Burgers’ equation are generated by the invariant subspace method.

  15. Optimality conditions for parabolic systems with variable coefficients involving Schrödinger operators

    Directory of Open Access Journals (Sweden)

    A.H. Qamlo

    2014-04-01

    Full Text Available In this paper, we study the existence of a solution to n × n parabolic systems with variable coefficients involving Schrödinger operators defined on an unbounded domain of Rn. We then discuss the necessary and sufficient conditions of optimality for these systems.

  16. Improved hyperbolic function method and exact solutions for variable coefficient Benjamin-Bona-Mahony-Burgers equation

    Directory of Open Access Journals (Sweden)

    Ma Hong-Cai

    2015-01-01

    Full Text Available By using the improved hyperbolic function method, we investigate the variable coefficient Benjamin-Bona-Mahony-Burgers equation which is very important in fluid mechanics. Some exact solutions are obtained. Under some conditions, the periodic wave leads to the kink-like wave.

  17. Multiplicity Results for Variable-Coefficient Singular Third-Order Differential Equation with a Parameter

    Directory of Open Access Journals (Sweden)

    Zhibo Cheng

    2014-01-01

    Full Text Available We investigate a class of variable coefficients singular third-order differential equation with superlinearity or sublinearity assumptions at infinity for an appropriately chosen parameter. By applications of Green’s function and the Krasnoselskii fixed point theorem, sufficient conditions for the existence of positive periodic solutions are established.

  18. A General Framework for Analytically Solving Advection-Dispersion Equation with Variable Coefficients

    Science.gov (United States)

    Chen, J. S.; Lai, K. H.

    2016-12-01

    Advection-dispersion equation (ADE) is widely used for simulation the contaminant transport in subsurface. Several analytical solutions to ADEs have been derived in the literature and served as fast tools for studying the various types of contaminant transport problems. Most of the available analytical solutions are derived for ADE with constant coefficients. Problems of radial advective-dispersive transport or scale-dependent advective-dispersive transport generally involve the ADEs with variables coefficients. However, there are very few analytical solutions to the ADEs with the variable coefficients. This study proposes a general framework for analytically solving advection-dispersion equation with variable coefficients. First, a Laplace transform with respect to the time variable is employed to convert the transient governing partial differential equations into an ordinary differential equation (ODE). Subsequently, the generalized integral transform techniques coupled with the power series method is use to remove the convert the ODE into an algebraic equation (AE) and the AE is solved using simple algebraic manipulations, easily yielding the solution in the transformed domain. The concentration solution in the original domain is ultimately obtained by successive applications of the Laplace and corresponding generalized integral transform inversions. A convergent flow tracer test is used to demonstrate the robustness of the proposed framework for deriving an exact analytical solution to the ADE with variable coefficients. The developed analytical solution is verified against a semi-analytical solution taken from the literature. The results show perfect agreement between our exact analytical solution and the semi-analytical solution. The solution method presented in this study can be applied to create more comprehensive analytical models for ADEs with variable coefficients.

  19. Singular 1-soliton solution of the nonlinear variable-coefficient diffusion reaction and mKdV equations

    Science.gov (United States)

    Guner, Ozkan; Bekir, Ahmet; Unsal, Omer; Cevikel, Adem C.

    2017-01-01

    In this paper, we pay attention to the analytical method named, ansatz method for finding the exact solutions of the variable-coefficient modified KdV equation and variable coefficient diffusion-reaction equation. As a result the singular 1-soliton solution is obtained. These solutions are important for the explanation of some practical physical problems. The obtained results show that these methods provides a powerful mathematical tool for solving nonlinear equations with variable coefficients. This method can be extended to solve other variable coefficient nonlinear partial differential equations.

  20. Exact solutions of time fractional heat-like and wave-like equations with variable coefficients

    Directory of Open Access Journals (Sweden)

    Zhang Sheng

    2016-01-01

    Full Text Available In this paper, a variable-coefficient time fractional heat-like and wave-like equation with initial and boundary conditions is solved by the use of variable separation method and the properties of Mittag-Leffler function. As a result, exact solutions are obtained, from which some known special solutions are recovered. It is shown that the variable separation method can also be used to solve some others time fractional heat-like and wave-like equation in science and engineering.

  1. Boundary-value problems for a third-order loaded parabolic-hyperbolic equation with variable coefficients

    Directory of Open Access Journals (Sweden)

    Bozor Islomov

    2015-08-01

    Full Text Available We prove the unique solvability of a boundary-value problems for a third-order loaded integro-differential equation with variable coefficients, by reducing the equation to a Volterra integral equation.

  2. An Efficient Method for Systems of Variable Coefficient Coupled Burgers’ Equation with Time-Fractional Derivative

    Directory of Open Access Journals (Sweden)

    Hossein Aminikhah

    2013-01-01

    Full Text Available A new homotopy perturbation method (NHPM is applied to system of variable coefficient coupled Burgers' equation with time-fractional derivative. The fractional derivatives are described in the Caputo fractional derivative sense. The concept of new algorithm is introduced briefly, and NHPM is examined for two systems of nonlinear Burgers' equation. In this approach, the solution is considered as a power series expansion that converges rapidly to the nonlinear problem. The new approximate analytical procedure depends on two iteratives. The modified algorithm provides approximate solutions in the form of convergent series with easily computable components. Results indicate that the introduced method is promising for solving other types of systems of nonlinear fractional-order partial differential equations.

  3. An efficient method for systems of variable coefficient coupled Burgers' equation with time-fractional derivative.

    Science.gov (United States)

    Aminikhah, Hossein; Malekzadeh, Nasrin

    2013-01-01

    A new homotopy perturbation method (NHPM) is applied to system of variable coefficient coupled Burgers' equation with time-fractional derivative. The fractional derivatives are described in the Caputo fractional derivative sense. The concept of new algorithm is introduced briefly, and NHPM is examined for two systems of nonlinear Burgers' equation. In this approach, the solution is considered as a power series expansion that converges rapidly to the nonlinear problem. The new approximate analytical procedure depends on two iteratives. The modified algorithm provides approximate solutions in the form of convergent series with easily computable components. Results indicate that the introduced method is promising for solving other types of systems of nonlinear fractional-order partial differential equations.

  4. Parallel accelerated cyclic reduction preconditioner for three-dimensional elliptic PDEs with variable coefficients

    KAUST Repository

    Chavez Chavez, Gustavo Ivan

    2017-12-07

    We present a robust and scalable preconditioner for the solution of large-scale linear systems that arise from the discretization of elliptic PDEs amenable to rank compression. The preconditioner is based on hierarchical low-rank approximations and the cyclic reduction method. The setup and application phases of the preconditioner achieve log-linear complexity in memory footprint and number of operations, and numerical experiments exhibit good weak and strong scalability at large processor counts in a distributed memory environment. Numerical experiments with linear systems that feature symmetry and nonsymmetry, definiteness and indefiniteness, constant and variable coefficients demonstrate the preconditioner applicability and robustness. Furthermore, it is possible to control the number of iterations via the accuracy threshold of the hierarchical matrix approximations and their arithmetic operations, and the tuning of the admissibility condition parameter. Together, these parameters allow for optimization of the memory requirements and performance of the preconditioner.

  5. Impact Time Guidance Law Considering Autopilot Dynamics Based on Variable Coefficients Strategy for Maneuvering Target

    Directory of Open Access Journals (Sweden)

    Wei Shang

    2015-01-01

    Full Text Available This paper investigates the terminal guidance problem for the missile intercepting a maneuvering target with impact time constraint. An impact time guidance law based on finite time convergence control theory is developed regarding the target motion as an unknown disturbance. To further improve the performance of the guidance law, an autopilot dynamics which is considered as a first-order lag is taken into consideration. In the proposed method, the coefficients change with the relative distance between missile and target. This variable coefficient strategy ensures that the missile impacts the target at the desired time with little final miss distance. Then it is proved that states of the guidance system converge to sliding mode in finite time under the proposed guidance law. Numerical simulations are presented to demonstrate the effectiveness of the impact time guidance law with autopilot dynamics (ITGAD.

  6. Numerical simulation of second-order hyperbolic telegraph type equations with variable coefficients

    Science.gov (United States)

    Pandit, Sapna; Kumar, Manoj; Tiwari, Surabhi

    2015-02-01

    In this article, the authors proposed a numerical scheme based on Crank-Nicolson finite difference scheme and Haar wavelets to find numerical solutions of different types of second order hyperbolic telegraph equations (i.e. telegraph equation with constant coefficients, with variable coefficients, and singular telegraph equation). This work is an extension of the scheme by Jiwari (2012) for hyperbolic equations. The use of Haar basis function is made with multiresolution analysis to get the fast and accurate results on collocation points. The convergence of the proposed scheme is proved by doing its error analysis. Four test examples are considered to demonstrate the accuracy and efficiency of the scheme. The scheme is easy and very suitable for computer implementation and provides numerical solutions close to the exact solutions and available in the literature.

  7. Role of de Vries in the rediscovery of Mendel's paper. II. Did de Vries really understand Mendel's paper?

    Science.gov (United States)

    Corcos, A F; Monaghan, F V

    1987-01-01

    In this paper, we discuss briefly three of the several lines of evidence that we believe demonstrate de Vries's lack of understanding of Mendel's paper. In our view, at least part of de Vries's failure of understanding derives from the fact that he appears to have viewed Mendel's paper as being mainly about the inheritance of characters that was his own interest. Therefore, he looked at it to see whether Mendel had found any laws of inheritance. Mendel had done his research for another purpose, to find the laws describing the formation of hybrids and the development of their offspring. Thus, de Vries started his examination of Mendel's paper with a very fundamental misunderstanding of what it was about.

  8. Uni-directional waves over slowly varying bottom, part II: Deformation of travelling waves

    NARCIS (Netherlands)

    Pudjaprasetya, S.R.; Pudjaprasetya, S.R.; van Groesen, Embrecht W.C.

    1996-01-01

    A new Korteweg-de Vries type of equation for uni-directional waves over slowly varying bottom has been derived in Part I. The equation retains the Hamiltonian structure of the underlying complete set of equations for surface waves. For flat bottom it reduces to the standard Korteweg-de Vries

  9. Manfred Ketz de Vries : tunne iseennast / Teeli Remmelg

    Index Scriptorium Estoniae

    Remmelg, Teeli

    2006-01-01

    Ilmunud ka: Delovõje Vedomosti 10. mai lk. 24. Professor Manfred Kets de Vries rääkis ettevõtete juhtidele, kuidas jõuda oma karjääris selgusele iseenda soovides. Kommenteerivad Valdur Laid ja Rait Hiiepuu

  10. On Solutions for Linear and Nonlinear Schrödinger Equations with Variable Coefficients: A Computational Approach

    Directory of Open Access Journals (Sweden)

    Gabriel Amador

    2016-05-01

    Full Text Available In this work, after reviewing two different ways to solve Riccati systems, we are able to present an extensive list of families of integrable nonlinear Schrödinger (NLS equations with variable coefficients. Using Riccati equations and similarity transformations, we are able to reduce them to the standard NLS models. Consequently, we can construct bright-, dark- and Peregrine-type soliton solutions for NLS with variable coefficients. As an important application of solutions for the Riccati equation with parameters, by means of computer algebra systems, it is shown that the parameters change the dynamics of the solutions. Finally, we test numerical approximations for the inhomogeneous paraxial wave equation by the Crank-Nicolson scheme with analytical solutions found using Riccati systems. These solutions include oscillating laser beams and Laguerre and Gaussian beams.

  11. Rosa de Vries: A Dutch Diva and Nineteenth-Century Trans-Atlantic Operatic Culture

    NARCIS (Netherlands)

    Metzelaar, H.

    2014-01-01

    In an arduous, twenty-year international career, Dutch opera soprano Rosa de Vries née van Os (1824-89) performed both French and Italian opera repertory with leading companies on both sides of the Atlantic. Experiencing triumphs and disappointments while managing both career and family, de Vries

  12. Numerical solutions and error estimations for the space fractional diffusion equation with variable coefficients via Fibonacci collocation method.

    Science.gov (United States)

    Bahşı, Ayşe Kurt; Yalçınbaş, Salih

    2016-01-01

    In this study, the Fibonacci collocation method based on the Fibonacci polynomials are presented to solve for the fractional diffusion equations with variable coefficients. The fractional derivatives are described in the Caputo sense. This method is derived by expanding the approximate solution with Fibonacci polynomials. Using this method of the fractional derivative this equation can be reduced to a set of linear algebraic equations. Also, an error estimation algorithm which is based on the residual functions is presented for this method. The approximate solutions are improved by using this error estimation algorithm. If the exact solution of the problem is not known, the absolute error function of the problems can be approximately computed by using the Fibonacci polynomial solution. By using this error estimation function, we can find improved solutions which are more efficient than direct numerical solutions. Numerical examples, figures, tables are comparisons have been presented to show efficiency and usable of proposed method.

  13. Ultrashort dark solitons interactions and nonlinear tunneling in the modified nonlinear Schrödinger equation with variable coefficient

    Science.gov (United States)

    Musammil, N. M.; Porsezian, K.; Nithyanandan, K.; Subha, P. A.; Tchofo Dinda, P.

    2017-09-01

    We present the study of the dark soliton dynamics in an inhomogeneous fiber by means of a variable coefficient modified nonlinear Schrödinger equation (Vc-MNLSE) with distributed dispersion, self-phase modulation, self-steepening and linear gain/loss. The ultrashort dark soliton pulse evolution and interaction is studied by using the Hirota bilinear (HB) method. In particular, we give much insight into the effect of self-steepening (SS) on the dark soliton dynamics. The study reveals a shock wave formation, as a major effect of SS. Numerically, we study the dark soliton propagation in the continuous wave background, and the stability of the soliton solution is tested in the presence of photon noise. The elastic collision behaviors of the dark solitons are discussed by the asymptotic analysis. On the other hand, considering the nonlinear tunneling of dark soliton through barrier/well, we find that the tunneling of the dark soliton depends on the height of the barrier and the amplitude of the soliton. The intensity of the tunneling soliton either forms a peak or valley and retains its shape after the tunneling. For the case of exponential background, the soliton tends to compress after tunneling through the barrier/well.

  14. The Interactions of N-Soliton Solutions for the Generalized (2+1-Dimensional Variable-Coefficient Fifth-Order KdV Equation

    Directory of Open Access Journals (Sweden)

    Xiangrong Wang

    2015-01-01

    Full Text Available A generalized (2+1-dimensional variable-coefficient KdV equation is introduced, which can describe the interaction between a water wave and gravity-capillary waves better than the (1+1-dimensional KdV equation. The N-soliton solutions of the (2+1-dimensional variable-coefficient fifth-order KdV equation are obtained via the Bell-polynomial method. Then the soliton fusion, fission, and the pursuing collision are analyzed depending on the influence of the coefficient eAij; when eAij=0, the soliton fusion and fission will happen; when eAij≠0, the pursuing collision will occur. Moreover, the Bäcklund transformation of the equation is gotten according to the binary Bell-polynomial and the period wave solutions are given by applying the Riemann theta function method.

  15. The generalized successive approximation and Padé Approximants method for solving an elasticity problem of based on the elastic ground with variable coefficients

    Directory of Open Access Journals (Sweden)

    Mustafa Bayram

    2017-01-01

    Full Text Available In this study, we have applied a generalized successive numerical technique to solve the elasticity problem of based on the elastic ground with variable coefficient. In the first stage, we have calculated the generalized successive approximation of being given BVP and in the second stage we have transformed it into Padé series. At the end of study a test problem has been given to clarify the method.

  16. Exact solutions of the nonlinear differential—difference equations associated with the nonlinear electrical transmission line through a variable-coefficient discrete (G'/G)-expansion method

    Science.gov (United States)

    Saïdou, Abdoulkary; Alidou, Mohamadou; Ousmanou, Dafounansou; Serge Yamigno, Doka

    2014-12-01

    We investigated exact traveling soliton solutions for the nonlinear electrical transmission line. By applying a concise and straightforward method, the variable-coefficient discrete (G'/G)-expansion method, we solve the nonlinear differential—difference equations associated with the network. We obtain some exact traveling wave solutions which include hyperbolic function solution, trigonometric function solution, rational solutions with arbitrary function, bright as well as dark solutions.

  17. Innlandsbosetting i tidlig metalltid : en analyse med utgangspunkt i Virdnejávri 112

    OpenAIRE

    Basso, Thor-Andreas

    2007-01-01

    Forskningen på innlandsbosetting i Finnmark har fram til nå hatt et mindre fokus enn kystområdene. Man har undersøkt få boplasser, og disse har i tillegg vært behandlet i en mindre grad. I denne oppgaven har jeg valgt å rette søkelyset på innlandsboplasser fra perioden tidlig metalltid, og har valgt å ta utgangspunkt i boplassen Virdnejávri 112. I oppgaven gjennomførtes det en boplasstruktur analyse av Virdnejávri 112, med hensyn til hvordan boplassen ble dannet (dvs. formasjon...

  18. Ärijuhtimisguru õpetab tasakaalus püsima / Manfred Kets de Vries ; interv. Endrik Randoja

    Index Scriptorium Estoniae

    Kets de Vries, Manfred

    2006-01-01

    Euroopa üheks juhtivamaks mõtlejaks peetav Manfred Kets de Vries vastab küsimustele, mis on juhtide peamised probleemid, kas isiklike probleemide lahendamisega saavutab inimene tasakaalu ka tööl ja mis on tasakaalu saavutamiseks kõige olulisem

  19. Periodic solutions of Wick-type stochastic Korteweg–de Vries ...

    Indian Academy of Sciences (India)

    ... paper, Kudrayshov method together with Hermite transform isimplemented to obtain exact solutions of Wick-type stochastic Korteweg–de Vries equation. Further, graphical illustrations in two- and three-dimensional plots of the obtained solutions depending on time and space are also given with white noise functionals.

  20. Periodic solutions of Wick-type stochastic Korteweg–de Vries ...

    Indian Academy of Sciences (India)

    2016-09-20

    Sep 20, 2016 ... engineering. Finding exact solutions of the Wick-type stochastic equation will be helpful in the theories and numerical studies of such equations. In this paper, Kudrayshov method together with Hermite transform is implemented to obtain exact solutions of Wick-type stochastic Korteweg–de Vries equation.

  1. De Vries & Mul, A.M. Cooper, Pioneer of Puppet Animation

    NARCIS (Netherlands)

    Wells, Paul

    2012-01-01

    abstractReview of Tjitte de Vries and Ati Mul, ‘They Thought it was a Marvel’. Arthur Melbourne Cooper (1874-1961) Pioneer of Puppet Animation. Amsterdam (Pallas Publications/AmsterdamUniversity Press) 2009, 576 p., 105 ill.; includesdvd of 6 films, isbn 978 908 555016 7

  2. Dark-dark solitons for a coupled variable-coefficient higher-order nonlinear Schrödinger system in an inhomogeneous optical fiber

    Science.gov (United States)

    Li, Ming-Zhen; Tian, Bo; Qu, Qi-Xing; Chai, Han-Peng; Liu, Lei; Du, Zhong

    2017-12-01

    In this paper, under investigation is a coupled variable-coefficient higher-order nonlinear Schrödinger system, which describes the simultaneous propagation of optical pulses in an inhomogeneous optical fiber. Based on the Lax pair and binary Darboux transformation, we present the nondegenerate N-dark-dark soliton solutions. With the graphical simulation, soliton propagation and interaction are discussed with the group velocity dispersion and fourth-order dispersion effects, which affect the velocity but have no effect on the amplitude. Linear, parabolic and periodic one dark-dark solitons are displayed. Interactions between the two solitons are presented as well, which are all elastic.

  3. Hamiltonian models for the propagation of irrotational surface gravity waves over a variable bottom.

    Science.gov (United States)

    Compelli, A; Ivanov, R; Todorov, M

    2018-01-28

    A single incompressible, inviscid, irrotational fluid medium bounded by a free surface and varying bottom is considered. The Hamiltonian of the system is expressed in terms of the so-called Dirichlet-Neumann operators. The equations for the surface waves are presented in Hamiltonian form. Specific scaling of the variables is selected which leads to approximations of Boussinesq and Korteweg-de Vries (KdV) types, taking into account the effect of the slowly varying bottom. The arising KdV equation with variable coefficients is studied numerically when the initial condition is in the form of the one-soliton solution for the initial depth.This article is part of the theme issue 'Nonlinear water waves'. © 2017 The Author(s).

  4. On the similarity solutions of the variable-coefficient semi-linear hyperbolic equation u{sub x}t={alpha}(t)f(u) via a symmetry method

    Energy Technology Data Exchange (ETDEWEB)

    Khater, A.H.; Abdul-Aziz, S.F.; Khidr, H.M.S. [Cairo University, Faculty of Science, Dept. of Mathematics, Beni-Suef (Egypt); Moussa, M.H.M. [Ain Shams University, Faculty of Education, Dept. of Mathematics, Cairo (Egypt)

    2001-08-01

    In a recent paper, Moussa and Sallam have obtained new similarity solutions for the semi-linear hyperbolic equation u{sub x}t =f(u), where f(u) including Liouville, phi-four, sine-Gordon, general form of Klein-Gordon, Mikhailov, and double sine-Gordon equations. Herein, it is extended the treatments to include the nonlinear Klein-Gordon, sinh-Gordon, Dodd-Bullough equations, f(u)=u{sup 1}-n, and f(u) is an arbitrary smooth function of u all with variable coefficient {alpha}(t). The infinitesimals, similarity variables, dependent variables, and reduction to quadrature or exact solutions have been tabulated for the mentioned relevant physical forms of f(u). Some interesting outcomes of this study are the deductions of the new exact solutions that, does not seem to have been reported in the literature.

  5. Well-posedness and exact controllability of a fourth order Schrodinger equation with variable coefficients and Neumann boundary control and collocated observation

    Directory of Open Access Journals (Sweden)

    Ruili Wen

    2016-08-01

    Full Text Available We consider an open-loop system of a fourth order Schrodinger equation with variable coefficients and Neumann boundary control and collocated observation. Using the multiplier method on Riemannian manifold we show that that the system is well-posed in the sense of Salamon. This implies that the exponential stability of the closed-loop system under the direct proportional output feedback control and the exact controllability of open-loop system are equivalent. So in order to conclude feedback stabilization from well-posedness, we study the exact controllability under a uniqueness assumption by presenting the observability inequality for the dual system. In addition, we show that the system is regular in the sense of Weiss, and that the feedthrough operator is zero.

  6. Waveguides of two-soliton solutions for the coupled KdV equations with variable coefficients in long-distance communication systems

    Science.gov (United States)

    Abdel-Gawad, H. I.; Tantawy, M.

    2017-06-01

    The aim of this paper is to study the collision between the long surface water waves. This is done by considering the coupled KdV equations with the relevant constrains on the variable coefficients. The extended rational traveling wave solutions are obtained. Various solutions of solitary waves, via soliton, periodic, elliptic and two-soliton solutions has also found. The waveguide properties of the characterizing two-soliton are shown to be a graded-index with reflection component and transmission with periodic distributions in long-distance communication. Here the linear refractive index and transmission are been shown to evolute towards solitonic waves enable to confirm data transverse by restricting expansion in low-cost telecommunications systems.

  7. Kuznetsov equation with variable coefficients

    Indian Academy of Sciences (India)

    Travelling wave-like solutions of the Zakharov–Kuznetsov equation with vari- able coefficients are studied using the ... exact solutions of nonlinear partial differential equations. Some of the most impor- tant methods are the ... In general, there is no standard method for solving nonlinear. PDEs and more so for PDEs in 2+1 ...

  8. Simulations and observation of nonlinear internal waves on the continental shelf: Korteweg–de Vries and extended Korteweg–de Vries solutions

    Directory of Open Access Journals (Sweden)

    K. O'Driscoll

    2017-09-01

    Full Text Available Numerical solutions of the Korteweg–de Vries (KdV and extended Korteweg–de Vries (eKdV equations are used to model the transformation of a sinusoidal internal tide as it propagates across the continental shelf. The ocean is idealized as being a two-layer fluid, justified by the fact that most of the oceanic internal wave signal is contained in the gravest mode. The model accounts for nonlinear and dispersive effects but neglects friction, rotation and mean shear. The KdV model is run for a number of idealized stratifications and unique realistic topographies to study the role of the nonlinear and dispersive effects. In all model solutions the internal tide steepens forming a sharp front from which a packet of nonlinear solitary-like waves evolve. Comparisons between KdV and eKdV solutions are made. The model results for realistic topography and stratification are compared with observations made at moorings off Massachusetts in the Middle Atlantic Bight. Some features of the observations compare well with the model. The leading face of the internal tide steepens to form a shock-like front, while nonlinear high-frequency waves evolve shortly after the appearance of the jump. Although not rank ordered, the wave of maximum amplitude is always close to the jump. Some features of the observations are not found in the model. Nonlinear waves can be very widely spaced and persist over a tidal period.

  9. Darboux transformation and soliton solutions for the generalized coupled variable-coefficient nonlinear Schrödinger-Maxwell-Bloch system with symbolic computation

    Science.gov (United States)

    Guo, Rui; Tian, Bo; Lü, Xing; Zhang, Hai-Qiang; Liu, Wen-Jun

    2012-04-01

    In an inhomogeneous nonlinear light guide doped with two-level resonant atoms, the generalized coupled variable-coefficient nonlinear Schrödinger-Maxwell-Bloch system can be used to describe the propagation of optical solitons. In this paper, the Lax pair and conservation laws of that model are derived via symbolic computation. Furthermore, based on the Lax pair obtained, the Darboux transformation is constructed and soliton solutions are presented. Figures are plotted to reveal the following dynamic features of the solitons: (1) Periodic mutual attractions and repulsions of four types of bound solitons: of two one-peak bright solitons; of two one-peak dark solitons; of two two-peak bright solitons and of two two-peak dark solitons; (2) Two types of elastic interactions of solitons: of two bright solitons and of two dark solitons; (3) Two types of parallel propagations of parabolic solitons: of two bright solitons and of two dark solitons. Those results might be useful in the study of optical solitons in some inhomogeneous nonlinear light guides.

  10. Integrability, solitons, periodic and travelling waves of a generalized (3+1)-dimensional variable-coefficient nonlinear-wave equation in liquid with gas bubbles

    Science.gov (United States)

    Deng, Gao-Fu; Gao, Yi-Tian

    2017-06-01

    Under investigation in this paper is a generalized (3+1)-dimensional varible-coefficient nonlinear-wave equation, which has been presented for nonlinear waves in liquid with gas bubbles. The bilinear form, Bäcklund transformation, Lax pair and infinitely-many conservation laws are obtained via the binary Bell polynomials. One-, two- and three-soliton solutions are generated by virtue of the Hirota method. Travelling-wave solutions are derived with the aid of the polynomial expansion method. The one-periodic wave solutions are constructed by the Hirota-Riemann method. Discussions among the soliton, periodic- and travelling-wave solutions are presented: I) the soliton velocities are related to the variable coefficients, while the soliton amplitudes are unaffected; II) the interaction between the solitons is elastic; III) there are three cases of the travelling-wave solutions, i.e., the triangle-type periodical, bell-type and soliton-type travelling-wave solutions, while we notice that bell-type travelling-wave solutions can be converted into one-soliton solutions via taking suitable parameters; IV) the one-periodic waves approach to the solitary waves under some conditions and can be viewed as a superposition of overlapping solitary waves, placed one period apart.

  11. Modulational instability, nonautonomous breathers and rogue waves for a variable-coefficient derivative nonlinear Schrödinger equation in the inhomogeneous plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Lei, E-mail: wanglei2239@126.com; Li, Min [Department of Mathematics and Physics, North China Electric Power University, Beijing 102206 (China); Qi, Feng-Hua [School of Information, Beijing Wuzi University, Beijing 101149 (China); Xu, Tao [College of Science, China University of Petroleum, Beijing 102249 (China)

    2015-03-15

    Under investigation in this paper is a variable-coefficient derivative nonlinear Schrödinger (vc-DNLS) equation modeling the nonlinear Alfvén waves in the inhomogeneous plasmas. The modulation instability is examined for this inhomogeneous nonlinear model. The nonautonomous breather and rogue wave solutions of the vc-DNLS equation are obtained via the modified Darboux transformation. It is found that the velocity and amplitude of the breather can be controlled by the inhomogeneous magnetic field and nonuniform density. Such novel phenomena as breather amplification and nonlinear Talbot effect-like property are demonstrated with the proper choices of the inhomogeneous parameters. Furthermore, dynamics of the fundamental rogue wave, periodical rogue wave, and composite rogue wave are graphically discussed. The trajectories and amplitudes of the rogue waves can be manipulated by the inhomogeneous magnetic field and nonuniform density. In addition, the nonlinear tunneling of the rogue waves and breathers is studied. As an application, a sample model is treated with our results, and the graphical illustrations exhibit the compressing, expanding, and fluctuating phenomena of the Alfvén rogue waves.

  12. Manfred F.R. KETS DE VRIES. Leadership et névroses organisationnelles

    OpenAIRE

    Perret, Véronique

    2009-01-01

    Un séminaire d'Abraham Zaleznik à la Harvard Business School intitulé « Psychologie psychanalytique et théorie de la gestion », va largement marquer les orientations que Manfred Kets de Vries donnera à sa carrière. Cette rencontre est une révélation, les thèses défendues par Zaleznik sur la nature humaine et sur les influences de l'inconscient humain sur la vie organisationnelle, vont l'amener à développer ses recherches sur le pouvoir et le management en s'appuyant sur la psychanalyse. Les t...

  13. Why the Rediscoverer Ended up on the Sidelines: Hugo De Vries's Theory of Inheritance and the Mendelian Laws

    Science.gov (United States)

    Stamhuis, Ida H.

    2015-01-01

    Eleven years before the `rediscovery' in 1900 of Mendel's work, Hugo De Vries published his theory of heredity. He expected his theory to become a big success, but it was not well-received. To find supporting evidence for this theory De Vries started an extensive research program. Because of the parallels of his ideas with the Mendelian laws and because of his use of statistics, he became one of the rediscoverers. However, the Mendelian laws, which soon became the foundation of a new discipline of genetics, presented a problem. De Vries was the only one of the early Mendelians who had developed his own theory of heredity. His theory could not be brought in line with the Mendelian laws. But because his original theory was still very dear to him, something important was at stake and he was unwilling to adapt his ideas to the new situation. He belittled the importance of the Mendelian laws and ended up on the sidelines.

  14. Why the Rediscoverer Ended up on the Sidelines: Hugo De Vries's Theory of Inheritance and the Mendelian Laws

    Science.gov (United States)

    Stamhuis, Ida H.

    2015-01-01

    Eleven years before the "rediscovery" in 1900 of Mendel's work, Hugo De Vries published his theory of heredity. He expected his theory to become a big success, but it was not well-received. To find supporting evidence for this theory De Vries started an extensive research program. Because of the parallels of his ideas with the…

  15. Voice recognition interfaces (VRI) optimize the utilization of theatre staff and time during laparoscopic cholecystectomy.

    Science.gov (United States)

    El-Shallaly, G E H; Mohammed, B; Muhtaseb, M S; Hamouda, A H; Nassar, A H M

    2005-01-01

    During laparoscopy, members of staff spend time setting up and de-activating the light source, camera and insufflator. Voice Recognition Interface (VRI) devices, such as HERMES (Stryker Europe, Montreux, Switzerland), enable the surgeon to perform and control these and other functions. They recognize the surgeon's voice and adjust the instruments in response to programmed verbal commands. The aim of this study was to evaluate HERMES with regards to the utilization of time and theatre staff during laparoscopic cholecystectomy. A total of 100 patients were randomized to either HERMES-assisted or standard laparoscopic cholecystectomy. Three time variables were measured for performing three VRI tasks: (1) The initial setting up of the light source and camera, (2) the activation of the insufflator, and (3) the deactivation of the insufflator and light source at the end of the operation. The mean (and standard deviation) of the time in seconds required for setting up the light source and camera was 27.6 (26.9) in non-HERMES operations and 11.7 (4.7) in HERMES-assisted cases (ptheatre staff during laparoscopic cholecystectomy.

  16. Pügmeede seitse õppetundi tõhusaks meeskonnatööks / Manfred Kets De Vries

    Index Scriptorium Estoniae

    Kets De Vries, Manfred

    2003-01-01

    Kesk-Aafrika vihmametsades pügmeede kogukonnas elanud Euroopa juhtimistreener Manfred Kets De Vries kirjeldab pügmeede igapäevatavasid, mida läänelikud organisatsioonid võiksid pidada efektiivse käitumise eeskujuks. Vt. samas: Psühhoanalüütikust juhtimisguru.

  17. Integrable and nonintegrable cases of the Lax equations with a source

    Science.gov (United States)

    Mel'Nikov, V. K.

    1994-06-01

    The Korteweg-de Vries equation with a source given as a Fourier integral over eigenfunctions of the so-called generating operator is considered. It is shown that, depending on the choice of the basis of the eigenfunctions, we have the following three possibilities: (1) evolution equations for the scattering data are nonintegrable; (2) evolution equations for the scattering data are integrable but the solution of the Cauchy problem for the Korteweg-de Vries equation with a source at some t'> t o leaves the considered class of functions decreasing rapidly enough as x→±∞; (3) evolution equations for the scattering data are integrable and the solution of the Cauchy problem for the Korteweg-de vries equation with a source exists at all t> t o. All these possibilities are widespread and occur in other Lax equations with a source.

  18. Korteweg–deVries equation for longitudinal disturbances in coasting charged-particle beams

    Directory of Open Access Journals (Sweden)

    Ronald C. Davidson

    2004-05-01

    Full Text Available This paper employs a one-dimensional kinetic model to investigate the nonlinear longitudinal dynamics of a long coasting beam propagating through a perfectly conducting circular pipe with radius r_{w}. The average axial electric field is expressed as ⟨E_{z}^{s}⟩=-e_{b}g_{0}∂λ_{b}/∂z-e_{b}g_{2}r_{w}^{2}∂^{3}λ_{b}/∂z^{3}, where g_{0} and g_{2} are constant geometric factors, and λ_{b}(z,t=∫dp_{z}F_{b}(z,p_{z},t is the line density. Assuming a waterbag distribution for the longitudinal distribution function F_{b}(z,p_{z},t, it is shown that weakly nonlinear disturbances moving near the sound speed evolve according to the Korteweg–deVries equation.

  19. Oral administration of the probiotic Lactobacillus fermentum VRI-003 and mucosal immunity in endurance athletes.

    Science.gov (United States)

    Cox, A J; Pyne, D B; Saunders, P U; Fricker, P A

    2010-03-01

    To evaluate the ability of a probiotic Lactobacillus fermentum VRI-003 (PCC) to enhance the mucosal immune system of elite athletes. A double-blind, placebo-controlled, crossover trial was conducted over a 4-month period of winter training. PARTICIPANTS; 20 healthy elite male distance runners. PCC was given at a daily dose of 1.26 x 10(10) as a freeze-dried powder in gelatin capsules. Placebo capsules contained an inert excipient. Treadmill performance (monthly), mucosal and systemic immunity (monthly), training (daily) and illness (daily) were assessed. Serum cytokine levels, salivary IgA levels and incidence, duration and severity of respiratory tract infections were measured. Subjects reported less than half the number of days of respiratory symptoms during PCC treatment (30 days) compared with placebo (72 days, ptrained distance runners. Maintenance of IFNgamma levels may be one mechanism underpinning the positive clinical outcomes.

  20. Ill-posedness for periodic nonlinear dispersive equations

    Directory of Open Access Journals (Sweden)

    Jaime Angulo Pava

    2010-08-01

    Full Text Available In this article, we establish new results about the ill-posedness of the Cauchy problem for the modified Korteweg-de Vries and the defocusing modified Korteweg-de Vries equations, in the periodic case. The lack of local well-posedness is in the sense that the dependence of solutions upon initial data fails to be continuous. We also develop a method for obtaining ill-posedness results in the periodic and non-periodic cases for the equations in the hierarchies of these equations and also in the case of the Benjamin-Ono equation.

  1. Hollandi paviljon Hannoveri maailmanäitusel EXPO 2000 : Uus Loodus = Dutch Pavilion at EXPO 2000 in Hannover : New Nature / Winy Maas, Jacob van Rijs, Nathalie de Vries

    Index Scriptorium Estoniae

    Maas, Winy

    2000-01-01

    Hollandi paviljon - näide looduse ja tehnoloogia segunemisest. Projekteerija: MVRDV. Arhitektid Winy Maas, Jacob van Rijs, Nathalie de Vries; kaasa töötasid Stefan Witteman, Jaap van Dijk, Chrisoph Schindler, Kristina Adsersen, Rüdiger Kreiselmayer

  2. The epileptology of Koolen-de Vries syndrome: Electro-clinico-radiologic findings in 31 patients.

    Science.gov (United States)

    Myers, Kenneth A; Mandelstam, Simone A; Ramantani, Georgia; Rushing, Elisabeth J; de Vries, Bert B; Koolen, David A; Scheffer, Ingrid E

    2017-06-01

    This study was designed to describe the spectrum of epilepsy phenotypes in Koolen-de Vries syndrome (KdVS), a genetic syndrome involving dysmorphic features, intellectual disability, hypotonia, and congenital malformations, that occurs secondary to 17q21.31 microdeletions and heterozygous mutations in KANSL1. We were invited to attend a large gathering of individuals with KdVS and their families. While there, we recruited individuals with KdVS and seizures, and performed thorough phenotyping. Additional subjects were included who approached us after the family support group brought attention to our research via social media. Inclusion criteria were genetic testing results demonstrating 17q21.31 deletion or KANSL1 mutation, and at least one seizure. Thirty-one individuals were studied, aged 2-35 years. Median age at seizure onset was 3.5 years, and 9 of 22 had refractory seizures 2 years after onset. Focal impaired awareness seizures were the most frequent seizure type occurring in 20 of 31, usually with prominent autonomic features. Twenty-one patients had prolonged seizures and, at times, refractory status epilepticus. Electroencephalography (EEG) showed focal/multifocal epileptiform discharges in 20 of 26. MRI studies of 13 patients were reviewed, and all had structural anomalies. Corpus callosum dysgenesis, abnormal hippocampi, and dilated ventricles were the most common, although periventricular nodular heterotopia, focal cortical dysplasia, abnormal sulcation, and brainstem and cerebellum abnormalities were also observed. One patient underwent epilepsy surgery for a lesion that proved to be an angiocentric glioma. The typical epilepsy phenotype of KdVS involves childhood-onset focal seizures that are prolonged and have prominent autonomic features. Multifocal epileptiform discharges are the typical EEG pattern. Structural brain abnormalities may be universal, including signs of abnormal neuroblast migration and abnormal axonal guidance. Epilepsy surgery should

  3. dJun and Vri/dNFIL3 are major regulators of cardiac aging in Drosophila.

    Directory of Open Access Journals (Sweden)

    Véronique Monnier

    Full Text Available Cardiac aging is a complex process, which is influenced by both environmental and genetic factors. Deciphering the mechanisms involved in heart senescence therefore requires identifying the molecular pathways that are affected by age in controlled environmental and genetic conditions. We describe a functional genomic investigation of the genetic control of cardiac senescence in Drosophila. Molecular signatures of heart aging were identified by differential transcriptome analysis followed by a detailed bio-informatic analysis. This approach implicated the JNK/dJun pathway and the transcription factor Vri/dNFIL3 in the transcription regulatory network involved in cardiac senescence and suggested the possible involvement of oxidative stress (OS in the aging process. To validate these predictions, we developed a new in vivo assay to analyze heart performance in various contexts of adult heart-specific gene overexpression and inactivation. We demonstrate that, as in mammals, OS plays a central role in cardiac senescence, and we show that pharmacological interventions impinging on OS slow heart senescence. These observations strengthen the idea that cardiac aging is controlled by evolutionarily conserved mechanisms, further validating Drosophila as a model to study cardiac senescence. In addition, we demonstrate that Vri, the ortholog of the vertebrate NFIL3/E4B4 transcription factor, is a major genetic regulator of cardiac aging. Vri overexpression leads to major heart dysfunctions, but its loss of function significantly reduces age-related cardiac dysfunctions. Furthermore, we unambiguously show that the JNK/AP1 pathway, the role of which in cardiac aging in mammals is controversial, is activated during cardiac aging and has a detrimental effect on cardiac senescence. This data-driven functional genomic analysis therefore led to the identification of key components of the Gene Regulatory Network of cardiac aging in Drosophila and may prompt to

  4. Manfred Kets de Vries: The Leadership Mystique – a users’ manual for the human enterprise. Prentice Hall, Great Britain. 2001.

    Directory of Open Access Journals (Sweden)

    Bryan Love

    2002-10-01

    Full Text Available Manfred Kets de Vries is one of Europe’s leading management thinkers and writers. He is an academic of international standing (Econ. Drs. Amsterdam, DBA Harvard & Psychoanalyst of International Psychoanalytical Association who currently holds the Chair of Human Resource Management at INSEAD. He is programme director of INSEAD’s top management programme, The Challenge of Leadership: Developing your Emotional Intelligence, and director of the INSEAD/HEC joint programme, Coaching and Consulting for Change. He also consults widely on organisational transformation and strategic human resource management.

  5. Differential geometry techniques for sets of nonlinear partial differential equations

    Science.gov (United States)

    Estabrook, Frank B.

    1990-01-01

    An attempt is made to show that the Cartan theory of partial differential equations can be a useful technique for applied mathematics. Techniques for finding consistent subfamilies of solutions that are generically rich and well-posed and for introducing potentials or other usefully consistent auxiliary fields are introduced. An extended sample calculation involving the Korteweg-de Vries equation is given.

  6. Formation of compression waves with multiscale asymptotics in the Burgers and KdV models

    OpenAIRE

    Zakharov, Sergei V.

    2015-01-01

    The Cauchy problem for the Burgers equation with a small dissipation and an initial weak discontinuity and the Cauchy problem with a large initial gradient for a quasilinear parabolic equation and for the Korteweg-de Vries (KdV) equation are considered. Multiscale asymptotics of solutions corresponding to shock waves are constructed. Some results can also be applied to rarefaction waves.

  7. Local well-posedness for the fifth-order KdV equations on T

    Science.gov (United States)

    Kwak, Chulkwang

    2016-05-01

    This paper is a continuation of the paper Low regularity Cauchy problem for the fifth-order modified KdV equations on T[7]. In this paper, we consider the fifth-order equation in the Korteweg-de Vries (KdV) hierarchy as following:

  8. Generalized solutions to the gKdV equation

    Directory of Open Access Journals (Sweden)

    Maurilio Marcio Melo

    2010-08-01

    Full Text Available In this article we study the Cauchy problem in $mathcal{G}_2((0,Times mathbb{R}$ (the algebra of generalized functions, in the sense of Colombeau for the generalized Korteweg-de Vries equation, with initial condition $varphi in mathcal{G}_2(mathbb{R}$, which contains $H^s(mathbb{R}$, for $sin mathbb{R}$.

  9. Multisoliton phase shifts in the case of a nonzero reflection coefficient

    NARCIS (Netherlands)

    Schuur, P.

    1984-01-01

    We study multisoliton solutions of the Korteweg-de Vries equation in the case of a nonzero reflection coefficient. An explicit phase shift formula is derived that clearly displays the nature of the interaction of each soliton with the other ones and with the dispersive wavetrain. In particular, this

  10. Modified electron acoustic field and energy applied to observation data

    Energy Technology Data Exchange (ETDEWEB)

    Abdelwahed, H. G., E-mail: hgomaa-eg@yahoo.com, E-mail: hgomaa-eg@mans.edu.eg [College of Science and Humanitarian Studies, Physics Department, Prince Sattam Bin Abdul Aziz University, Alkharj 11942 (Saudi Arabia); Theoretical Physics Research Group, Physics Department, Faculty of Science, Mansoura University, Mansoura 35516 (Egypt); El-Shewy, E. K. [Theoretical Physics Research Group, Physics Department, Faculty of Science, Mansoura University, Mansoura 35516 (Egypt)

    2016-08-15

    Improved electrostatic acoustic field and energy have been debated in vortex trapped hot electrons and fluid of cold electrons with pressure term plasmas. The perturbed higher-order modified-Korteweg-de Vries equation (PhomKdV) has been worked out. The effect of trapping and electron temperatures on the electro-field and energy properties in auroral plasmas has been inspected.

  11. On the study of ion-acoustic solitary waves and double-layers in a ...

    Indian Academy of Sciences (India)

    Using the pseudopotential method, theoretical investigation has been made on the first-order Korteweg-deVries ion-acoustic solitons in a multicomponent plasma consisting of warm positive ions, negative ions and isothermal electrons. The effects of electron-inertia and drift motion of the ions on the amplitudes and widths of ...

  12. Effects of ion-fluid temperature on dust-ion-acoustic solitons

    Indian Academy of Sciences (India)

    The properties of dust-ion-acoustic (DIA) solitons in an unmagnetized dusty plasma, whose constituents are adiabatic ion-fluid, Boltzmann electrons, and static dust particles, are investigated by employing the reductive perturbation method. The Korteweg-de Vries equation is derived and its stationary solution is numerically ...

  13. Ion-acoustic solitons in multispecies spatially inhomogeneous ...

    Indian Academy of Sciences (India)

    Ion-acoustic solitons are investigated in the spatially inhomogeneous plasma having electrons-positrons and ions. The soliton characteristics are described by Korteweg-de Vries equation which has an additional term. The density and temperature of different species play an important role for the amplitude and width of the ...

  14. On the study of ion-acoustic solitary waves and double-layers in a ...

    Indian Academy of Sciences (India)

    Abstract. Using the pseudopotential method, theoretical investigation has been made on the first- order Korteweg-deVries ion-acoustic solitons in a multicomponent plasma consisting of warm pos- itive ions, negative ions and isothermal electrons. The effects of electron-inertia and drift motion of the ions on the amplitudes ...

  15. Solitary Rossby waves in the lower tropical troposphere | Lenouo ...

    African Journals Online (AJOL)

    Weakly nonlinear approximation is used to study the theoretical comportment of large-scale disturbances around the inter-tropical mid-tropospheric jet. We show here that the Korteweg de Vries (KdV) theory is appropriated to describe the structure of the streamlines around the African easterly jet (AEJ) region.

  16. Nonlinear Stability of MKdV Breathers

    DEFF Research Database (Denmark)

    Alejo Plana, Miguel Angel; Muñoz, Claudio

    2013-01-01

    Breather solutions of the modified Korteweg-de Vries equation are shown to be globally stable in a natural H 2 topology. Our proof introduces a new Lyapunov functional, at the H 2 level, which allows to describe the dynamics of small perturbations, including oscillations induced by the periodicity...

  17. Riemann type algebraic structures and their differential-algebraic integrability analysis

    Directory of Open Access Journals (Sweden)

    Prykarpatsky A.K.

    2010-06-01

    Full Text Available The differential-algebraic approach to studying the Lax type integrability of generalized Riemann type equations is devised. The differentiations and the associated invariant differential ideals are analyzed in detail. The approach is also applied to studying the Lax type integrability of the well known Korteweg-de Vries dynamical system.

  18. Analytical solutions of jam pattern formation on a ring for a class of optimal velocity traffic models

    DEFF Research Database (Denmark)

    Gaididei, Yuri Borisovich; Berkemer, Rainer; Caputo, Jean Guy

    2009-01-01

    are found analytically. Their velocity and amplitude are determined from a perturbation approach based on collective coordinates with the discrete modified Korteweg-de Vries equation as the zero order equation. This contains the standard OV model as a special case. The analytical results are in excellent...

  19. A Statistical Model for Soliton Particle Interaction in Plasmas

    DEFF Research Database (Denmark)

    Dysthe, K. B.; Pécseli, Hans; Truelsen, J.

    1986-01-01

    A statistical model for soliton-particle interaction is presented. A master equation is derived for the time evolution of the particle velocity distribution as induced by resonant interaction with Korteweg-de Vries solitons. The detailed energy balance during the interaction subsequently determines...

  20. Application of He’s Variational Iteration Method to Nonlinear Helmholtz Equation and Fifth-Order KDV Equation

    DEFF Research Database (Denmark)

    Miansari, Mo; Miansari, Me; Barari, Amin

    2009-01-01

    In this article, He’s variational iteration method (VIM), is implemented to solve the linear Helmholtz partial differential equation and some nonlinear fifth-order Korteweg-de Vries (FKdV) partial differential equations with specified initial conditions. The initial approximations can be freely...

  1. Coupled KdV equations of Hirota-Satsuma type

    CERN Document Server

    Sakovich, S Yu

    1999-01-01

    It is shown that the system of two coupled Korteweg - de Vries equations passes the Painleve test for integrability in nine distinct cases of its coefficients. The integrability of eight cases is verified by direct construction of Lax pairs, whereas for one case it remains unknown.

  2. Solitons and Weakly Nonlinear Waves in Plasmas

    DEFF Research Database (Denmark)

    Pécseli, Hans

    1985-01-01

    Theoretical descriptions of solitons and weakly nonlinear waves propagating in plasma media are reviewed, with particular attention to the Korteweg-de Vries (KDV) equation and the Nonlinear Schrödinger equation (NLS). The modifications of these basic equations due to the effects of resonant...

  3. Analysis of Stokes waves theory as a diffusion problem | Okeke ...

    African Journals Online (AJOL)

    This mathematical model concerns the theory of Stokes waves. These wave types belong to the class of ocean surface waves found in deep and intermediate waters. In this consideration, the fifth order expansion was obtained using Korteweg de Vries equation with diffusion term. This study suggests that the phase velocity ...

  4. A nonstandard numerical method for the modified KdV equation

    Science.gov (United States)

    Aydin, Ayhan; Koroglu, Canan

    2017-11-01

    A linearly implicit nonstandard finite difference method is presented for the numerical solution of modified Korteweg-de Vries equation. Local truncation error of the scheme is discussed. Numerical examples are presented to test the efficiency and accuracy of the scheme.

  5. VEGFR tyrosine kinase inhibitor II (VRI) induced vascular insufficiency in zebrafish as a model for studying vascular toxicity and vascular preservation

    Energy Technology Data Exchange (ETDEWEB)

    Li, Shang; Dang, Yuan Ye; Oi Lam Che, Ginny [State Key Laboratory of Quality Research in Chinese Medicine and Institute of Chinese Medical Sciences, University of Macau, Avenida da Universidade, Taipa, Macao (China); Kwan, Yiu Wa [School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong (China); Chan, Shun Wan [State Key Laboratory of Chinese Medicine and Molecular Pharmacology, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong (China); Leung, George Pak Heng [Pharmacology and Pharmacy, Faculty of Medicine, The University of Hong Kong, Hong Kong (China); Lee, Simon Ming Yuen, E-mail: simonlee@umac.mo [State Key Laboratory of Quality Research in Chinese Medicine and Institute of Chinese Medical Sciences, University of Macau, Avenida da Universidade, Taipa, Macao (China); Hoi, Maggie Pui Man, E-mail: maghoi@umac.mo [State Key Laboratory of Quality Research in Chinese Medicine and Institute of Chinese Medical Sciences, University of Macau, Avenida da Universidade, Taipa, Macao (China)

    2014-11-01

    In ischemic disorders such as chronic wounds and myocardial ischemia, there is inadequate tissue perfusion due to vascular insufficiency. Besides, it has been observed that prolonged use of anti-angiogenic agents in cancer therapy produces cardiovascular toxicity caused by impaired vessel integrity and regeneration. In the present study, we used VEGFR tyrosine kinase inhibitor II (VRI) to chemically induce vascular insufficiency in zebrafish in vivo and human umbilical vein endothelial cells (HUVEC) in vitro to further study the mechanisms of vascular morphogenesis in these pathological conditions. We also explored the possibility of treating vascular insufficiency by enhancing vascular regeneration and repair with pharmacological intervention. We observed that pretreatment of VRI induced blood vessel loss in developing zebrafish by inhibiting angiogenesis and increasing endothelial cell apoptosis, accompanied by down-regulation of kdr, kdrl and flt-1 genes expression. The VRI-induced blood vessel loss in zebrafish could be restored by post-treatment of calycosin, a cardiovascular protective isoflavone. Similarly, VRI induced cytotoxicity and apoptosis in HUVEC which could be rescued by calycosin post-treatment. Further investigation of the underlying mechanisms showed that the PI3K/AKT/Bad cell survival pathway was a main contributor of the vascular regenerative effect of calycosin. These findings indicated that the cardiovascular toxicity in anti-angiogenic therapy was mainly caused by insufficient endothelial cell survival, suggesting its essential role in vascular integrity, repair and regeneration. In addition, we showed that VRI-induced blood vessel loss in zebrafish represented a simple and effective in vivo model for studying vascular insufficiency and evaluating cancer drug vascular toxicities. - Highlights: • In vivo VRI model • Rescue effects of calycosin • Calycosin EC survival pathways.

  6. Electric-field-dependent dielectric response in the de Vries-type smectic- A* phase possessing local orientational order with nanoscale correlation length

    OpenAIRE

    VIJ, JAGDISH; MANNA, UTTAM; SONG, JANG-KUN

    2008-01-01

    PUBLISHED The dielectric strength is shown to increase and the relaxation frequency to decrease for a large temperature range up to a certain value of the electric field in the smectic-A* phase. This behavior contrasts to that observed in a conventional smectic-A*, but can be explained in terms of de Vries scenerio. On assuming the reorientation of the molecular dipoles with electric field to be of the Langevin type in the de Vries smectic-A*, we find that around 1300 molecules, correspond...

  7. A Comparison of Solutions of Two Model Equations for Long Waves.

    Science.gov (United States)

    1983-02-01

    1/ (c 3 2t) (27) at least for0 <t C 3 /2, where 0 j k. Remark. We continue to use the symbol u(r) introduced in (17) to denote the rt derivative of u...de Vries equation. S.I.A.M. Rev. 14, 582. 14.Kano, T. and Nishida, T. 1983 Sur l’equation de Korteweg-de Vries. Une thiorie mathematique . (to appear

  8. Observation of the de Vries behavior in SmA* phase of a liquid crystal using polarised Raman scattering and infrared spectroscopy

    Science.gov (United States)

    Kocot, A.; Vij, J. K.; Perova, T. S.; Merkel, K.; Swaminathan, V.; Sreenilayam, S. P.; Yadav, N.; Panov, V. P.; Stevenson, P. J.; Panov, A.; Rodriguez-Lojo, D.

    2017-09-01

    Two approaches exist in the literature for describing the orientational distribution function (ODF) of the molecular directors in SmA* phase of liquid crystals, though several models are recently proposed in the literature for explaining the de Vries behaviour. These ODFs correspond to either the conventional unimodal arrangements of molecular directors arising from the mean field theory that leads to the broad or sugar-loaf like distribution or to the "diffuse-cone-shaped" type distribution proposed by de Vries. The hypothesis by de Vries provides for a realistic explanation as to how at a molecular level, a first-order SmA* to SmC* transition can occur where the uniform molecular director azimuthal distributions condense to values lying within a narrow range of angles; finally these condense to a single value while at the same time ensuring a little or no concomitant shrinkage in the layer spacing. The azimuthal distribution of the in-layer directors is probed using IR and polarized Raman spectroscopic techniques. The latter allows us to obtain the ODF and the various order parameters for the uniaxial and the biaxial phases. Based on the results of these measurements, we conclude that the "cone-shaped" (or volcano-shaped) de Vries type of distribution can most preferably describe SmA* where "a first-order phase transition from SmA* to SmC*" and a low layer shrinkage can both be easily explained.

  9. Orientational order parameters of a de Vries-type ferroelectric liquid crystal obtained by polarized Raman spectroscopy and x-ray diffraction.

    Science.gov (United States)

    Sanchez-Castillo, A; Osipov, M A; Jagiella, S; Nguyen, Z H; Kašpar, M; Hamplovă, V; Maclennan, J; Giesselmann, F

    2012-06-01

    The orientational order parameters (P{2}) and (P{4}) of the ferroelectric, de Vries-type liquid crystal 9HL have been determined in the SmA and SmC phases by means of polarized Raman spectroscopy, and in the SmA phase using x-ray diffraction. Quantum density functional theory predicts Raman spectra for 9HL that are in good agreement with the observations and indicates that the strong Raman band probed in the experiment corresponds to the uniaxial, coupled vibration of the three phenyl rings along the molecular long axis. The magnitudes of the orientational order parameters obtained in the Raman and x-ray experiments differ dramatically from each other, a discrepancy that is resolved by considering that the two techniques probe the orientational distributions of different molecular axes. We have developed a systematic procedure in which we calculate the angle between these axes and rescale the orientational order parameters obtained from x-ray scattering with results that are then in good agreement with the Raman data. At least in the case of 9HL, the results obtained by both techniques support a "sugar loaf" orientational distribution in the SmA phase with no qualitative difference to conventional smectics A. The role of individual molecular fragments in promoting de Vries-type behavior is considered.

  10. 1980 Summer Study Program in Geophysical Fluid Dynamics - Coherent Features in Geophysical Flows.

    Science.gov (United States)

    1980-11-01

    Redekopp, Larry University of Southern California Rhines, Peter Woods Hole Oceanographic Institution Rizzoli, Paola Laboratorio Dinamica Grandi Masse...as the Korteweg-de Vries equation, are familiar from surface wave theory; others such as the modon solutions were first derived in the context of f3...conservation statements in the form S(8b) If the streamlines extend to c , B can be evaluated in the familiar fashion by requiring that the eddy be

  11. Analytic well-posedness of periodic gKdV

    Science.gov (United States)

    Himonas, A. Alexandrou; Petronilho, Gerson

    In the periodic case, it is proved that the Cauchy problem for the generalized Korteweg-de Vries equation (gKdV) is locally well-posed in a class of analytic functions that can be extended holomorphically in a symmetric strip of the complex plane around the x-axis. Thus, the uniform analyticity radius of the solution does not change as time progresses. Also, information about the regularity of the solution in the time variable is provided.

  12. Chaos problems in observer's mathematics

    Science.gov (United States)

    Khots, Boris; Khots, Dmitriy

    This work considers the solution of Cauchy problem (initial value problem) in a setting of arithmetic, algebra, and topology provided by Observer's Mathematics (see www.mathrelativity.com) and applies this solution to free wave equation, the linear (time-dependent) Schrodinger equation, the (time-dependent) Airy equation, the Korteweg-de Vries (KdV) equation, and quantum theory of two-slit interference. Certain results and communications pertaining to these problems are provided.

  13. Diagramas de Bianchi para Susy

    Directory of Open Access Journals (Sweden)

    Sara Cruz y Cruz

    2006-01-01

    Full Text Available Se revisa el origen de los solitones como soluciones de la ecuación de Korteweg-de Vries y su presencia en la formulación supersimétrica de la Mecánica Cuántica. Se introducen los diagramas de Bianchi como una herramienta simbólica para construir socios supersimétricos de un Hamiltoniano dado.

  14. Lattice Boltzmann Methods for Fluid Structure Interaction

    Science.gov (United States)

    2012-09-01

    Approved By: Knox T. Millsaps, Professor & Chair, Dept. of Mechanical & Aerospace Engineering Approved By: Doug Moses, Vice Provost for Academic Affairs...similar procedure including the Burgers Equation [10], the Korteweg-de Vries equation [11], the Brinkman equation [12] and the Schrödinger equation [13...method for a two-dimensional viscous Burgers equation: Computational results.,” in Supercomputing, pp. 242–252, 1991. [11] G. Yan and J. Zhang, “A higher

  15. Study of stability and dynamical properties of Rosenau-Hyman compactons

    Science.gov (United States)

    Mihaila, Bogdan; Cardenas, Andres; Cooper, Fred

    2010-03-01

    We use Pade approximants to study numerically the stability and dynamical properties of K(2,2) Rosenau-Hyman compactons. We present a systematic derivation of Pade approximants for calculating the derivatives of smooth functions on an uniform grid and we illustrate our finding by improving upon traditional fourth-order finite-differences formulas. This study is intended as a stepping block towards a systematic numerical study of soliton solutions with a compact support of generalized Korteweg-de Vries equations.

  16. Soliton solutions of the two-dimensional KdV-Burgers equation by homotopy perturbation method

    Energy Technology Data Exchange (ETDEWEB)

    Molabahrami, A. [Department of Mathematics, Ilam University, PO Box 69315516, Ilam (Iran, Islamic Republic of)], E-mail: a_m_bahrami@yahoo.com; Khani, F. [Department of Mathematics, Ilam University, PO Box 69315516, Ilam (Iran, Islamic Republic of); Bakhtar Institute of Higher Education, PO Box 696, Ilam (Iran, Islamic Republic of)], E-mail: farzad_khani59@yahoo.com; Hamedi-Nezhad, S. [Bakhtar Institute of Higher Education, PO Box 696, Ilam (Iran, Islamic Republic of)

    2007-10-29

    In this Letter, the He's homotopy perturbation method (HPM) to finding the soliton solutions of the two-dimensional Korteweg-de Vries Burgers' equation (tdKdVB) for the initial conditions was applied. Numerical solutions of the equation were obtained. The obtained solutions, in comparison with the exact solutions admit a remarkable accuracy. The results reveal that the HPM is very effective and simple.

  17. Matrix generalizations of integrable systems with Lax integro-differential representations

    Directory of Open Access Journals (Sweden)

    Sydorenko Yu.M.

    2012-06-01

    Full Text Available We found matrix integro-differential Lax representations forDavey-Stewartson systems (DS-I, DS-II, DS-III, (2+1-dimensionalgeneralizations of Chen-Lee-Liu equation and its higher symmetries.In particular, we obtain (2+1-dimensional generalizations ofmodified Korteweg-de Vries equation, Nizhnik equation and so etc. Wealso propose some matrix multidimensional generalizations of Burgersequation.

  18. Time evolution of nonplanar dust ion-acoustic solitary waves in a charge varying dusty plasma with superthermal electrons

    Energy Technology Data Exchange (ETDEWEB)

    Mayout, Saliha; Tribeche, Mouloud, E-mail: mouloudtribeche@yahoo.fr [Plasma Physics Group (PPG), Theoretical Physics Laboratory (TPL), Faculty of Sciences- Physics, University of Bab-Ezzouar, U.S.T.H.B, B.P. 32, El Alia, Algiers 16111 (Algeria); Sahu, Biswajit [Department of Mathematics, West Bengal State University, Barasat, Kolkata-700126 (India)

    2015-12-15

    A theoretical study on the nonlinear propagation of nonplanar (cylindrical and spherical) dust ion-acoustic solitary waves (DIASW) is carried out in a dusty plasma, whose constituents are inertial ions, superthermal electrons, and charge fluctuating stationary dust particles. Using the reductive perturbation theory, a modified Korteweg-de Vries equation is derived. It is shown that the propagation characteristics of the cylindrical and spherical DIA solitary waves significantly differ from those of their one-dimensional counterpart.

  19. Internal Solitons in the Oceans

    Science.gov (United States)

    2006-01-01

    Mecanique , 332, 525-530. 42. Craik, A. D. D., 1985, Wave Interactions and Fluid Flows, Cambridge University Press, 322 pp. 43. Das, K. P., and J...7 3.3 Internal Waves in Nonrotating Fluids ............................. 10 3.3.1 The Korteweg-de Vries (KdV) Equation...of solitons in a stratified, sheared, rotating fluid and (b) some of the observational and experimental evidence for their existence. Isolated

  20. Rational Solutions to the ABS List: Transformation Approach

    Science.gov (United States)

    Zhang, Danda; Zhang, Da-Jun

    2017-10-01

    In the paper we derive rational solutions for the lattice potential modified Korteweg-de Vries equation, and Q2, Q1(δ), H3(δ), H2 and H1 in the Adler-Bobenko-Suris list. Bäcklund transformations between these lattice equations are used. All these rational solutions are related to a unified τ function in Casoratian form which obeys a bilinear superposition formula.

  1. Modified Korteweg–de Vries equation in a negative ion rich hot adiabatic dusty plasma with non-thermal ion and trapped electron

    Energy Technology Data Exchange (ETDEWEB)

    Adhikary, N. C., E-mail: nirab-iasst@yahoo.co.in [Physical Sciences Division, Institute of Advanced Study in Science and Technology, Vigyan Path, Paschim Boragaon, Garchuk, Guwahati 781035, Assam (India); Deka, M. K. [Centre of Plasma Physics, Tepesia, Sonapur, Assam (India); Dev, A. N. [Department of Science and Humanities, College of Science and Technology, Rinchending, Phuentsholing (Bhutan); Department of Mathematics, R. G. Baruah College, Guwahati 781025, Assam (India); Sarmah, J. [Department of Mathematics, R. G. Baruah College, Guwahati 781025, Assam (India)

    2014-08-15

    In this report, the investigation of the properties of dust acoustic (DA) solitary wave propagation in an adiabatic dusty plasma including the effect of the non-thermal ions and trapped electrons is presented. The reductive perturbation method has been employed to derive the modified Korteweg–de Vries (mK-dV) equation for dust acoustic solitary waves in a homogeneous, unmagnetized, and collisionless plasma whose constituents are electrons, singly charged positive ions, singly charged negative ions, and massive charged dust particles. The stationary analytical solution of the mK-dV equation is numerically analyzed and where the effect of various dusty plasma constituents DA solitary wave propagation is taken into account. It is observed that both the ions in dusty plasma play as a key role for the formation of both rarefactive as well as the compressive DA solitary waves and also the ion concentration controls the transformation of negative to positive potentials of the waves.

  2. Approximate Solutions of Fisher's Type Equations with Variable Coefficients

    Directory of Open Access Journals (Sweden)

    A. H. Bhrawy

    2013-01-01

    Full Text Available The spectral collocation approximations based on Legendre polynomials are used to compute the numerical solution of time-dependent Fisher’s type problems. The spatial derivatives are collocated at a Legendre-Gauss-Lobatto interpolation nodes. The proposed method has the advantage of reducing the problem to a system of ordinary differential equations in time. The four-stage A-stable implicit Runge-Kutta scheme is applied to solve the resulted system of first order in time. Numerical results show that the Legendre-Gauss-Lobatto collocation method is of high accuracy and is efficient for solving the Fisher’s type equations. Also the results demonstrate that the proposed method is powerful algorithm for solving the nonlinear partial differential equations.

  3. Variable-coefficient nonisospectral Toda lattice hierarchy and its ...

    Indian Academy of Sciences (India)

    coefficient nonisospectral Toda lattice hierarchy; exact solution; compatibility condition; inverse scattering transformation. ... In order to solve the derived Toda lattice hierarchy, the inverse scattering transformation is utilized. As a result, new and ...

  4. \\bar{\\partial }-problem and Cauchy matrix for the mKdV equation with self-consistent sources

    Science.gov (United States)

    Zhu, Junyi; Zhou, Dewen; Geng, Xianguo

    2014-06-01

    The modified Korteweg-de Vries (mKdV) and Maxwell-Bloch system is studied by using the dressing method based on the local 2 × 2 matrix \\bar{\\partial }-problem. By virtue of a singular dispersion relation, we derive the present mKdV equation with self-consistent sources which change the velocities of the solitons. The explicit solutions, including the bright and dark type N-soliton solutions due to different forms of the spectral transform matrix, are given by virtue of the properties of the Cauchy matrix.

  5. Gevrey regularity of the periodic gKdV equation

    Science.gov (United States)

    Hannah, Heather; Himonas, A. Alexandrou; Petronilho, Gerson

    2011-03-01

    Using the multilinear estimates, which were derived for proving well-posedness of the generalized Korteweg-de Vries (gKdV) equation, it is shown that if the initial data belongs to Gevrey space G, σ⩾1, in the space variable then the solution to the corresponding Cauchy problem for gKdV belongs also to G in the space variable. Moreover, the solution is not necessarily G in the time variable. However, it belongs to G3σ near 0. When σ=1 these are analytic regularity results for gKdV.

  6. Cauchy problems for fifth-order KdV equations in weighted Sobolev spaces

    Directory of Open Access Journals (Sweden)

    Eddye Bustamante

    2015-05-01

    Full Text Available In this work we study the initial-value problem for the fifth-order Korteweg-de Vries equation $$ \\partial_{t}u+\\partial_{x}^{5}u+u^k\\partial_{x}u=0, \\quad x,t\\in \\mathbb{R}, \\; k=1,2, $$ in weighted Sobolev spaces $H^s(\\mathbb{R}\\cap L^2(\\langle x \\rangle^{2r}dx$. We prove local and global results. For the case $k=2$ we point out the relationship between decay and regularity of solutions of the initial-value problem.

  7. An application of the decomposition method for the generalized KdV and RLW equations

    CERN Document Server

    Kaya, D

    2003-01-01

    We consider solitary-wave solutions of the generalized regularized long-wave (RLW) and Korteweg-de Vries (KdV) equations. We prove the convergence of Adomian decomposition method applied to the generalized RLW and KdV equations. Then we obtain the exact solitary-wave solutions and numerical solutions of the generalized RLW and KdV equations for the initial conditions. The numerical solutions are compared with the known analytical solutions. Their remarkable accuracy are finally demonstrated for the generalized RLW and KdV equations.

  8. Cylindrical electron acoustic solitons for modified time-fractional nonlinear equation

    Science.gov (United States)

    Abdelwahed, H. G.; El-Shewy, E. K.; Mahmoud, Abeer A.

    2017-08-01

    The modulation of cylindrical electron acoustic characteristics using a time fractal modified nonlinear equation has been investigated in nonisothermal plasmas. The time fractional cylindrical modified-Korteweg-de Vries equation has been obtained by Agrawal's analysis. A cylindrical localized soliton has been obtained via the Adomian decomposition method. The pressure term and cylindrical time fractional effects on the modulated wave properties have been investigated with comparative auroral observations. It is established that the presence of the fractional order factor not only significantly modifies the solitary characteristics but also varies the profile polarity.

  9. Soliton reflection in a magnetized inhomogeneous warm plasma: effect of ionization

    Science.gov (United States)

    Malik, Hitendra K.; Jyoti; Kumar, Ravinder

    2014-04-01

    The reflection of nonlinear solitary waves is studied in a plasma under the effect of an external magnetic field and constant ionization along with finite ion temperature. To investigate the reflection of solitary waves, relevant modified Korteweg-deVries equations for the right and left going waves are derived, and coupled at the point of reflection for obtaining the expression of reflection coefficient. The solitary waves are found to shift after their reflection. Variation of reflection coefficient and shift are studied for different plasma parameters like ion temperature, ionization rate and wave propagation angle or the obliqueness of magnetic field.

  10. Extension of the homotopy pertubation method for solving nonlinear differential-difference equations

    Energy Technology Data Exchange (ETDEWEB)

    Mousa, Mohamed Medhat [Benha Univ. (Egypt). Benha High Inst. of Technology; Al-Farabi Kazakh National Univ., Almaty (Kazakhstan); Kaltayev, Aidarkan [Al-Farabi Kazakh National Univ., Almaty (Kazakhstan); Bulut, Hasan [Firat Univ., Elazig (Turkey). Dept. of Mathematics

    2010-12-15

    In this paper, we have extended the homotopy perturbation method (HPM) to find approximate analytical solutions for some nonlinear differential-difference equations (NDDEs). The discretized modified Korteweg-de Vries (mKdV) lattice equation and the discretized nonlinear Schroedinger equation are taken as examples to demonstrate the validity and the great potential of the HPM in solving such NDDEs. Comparisons are made between the results of the presented method and exact solutions. The obtained results reveal that the HPM is a very effective and convenient tool for solving such kind of equations. (orig.)

  11. Orbital stability of periodic traveling-wave solutions for the log-KdV equation

    Science.gov (United States)

    Natali, Fábio; Pastor, Ademir; Cristófani, Fabrício

    2017-09-01

    In this paper we establish the orbital stability of periodic waves related to the logarithmic Korteweg-de Vries equation. Our motivation is inspired in the recent work [3], in which the authors established the well-posedness and the linear stability of Gaussian solitary waves. By using the approach put forward recently in [20] to construct a smooth branch of periodic waves as well as to get the spectral properties of the associated linearized operator, we apply the abstract theories in [13] and [25] to deduce the orbital stability of the periodic traveling waves in the energy space.

  12. Long-distance pulse propagation on high-frequency dissipative nonlinear transmission lines/resonant tunneling diode line cascaded maps

    Energy Technology Data Exchange (ETDEWEB)

    Klofai, Yerima [Department of Physics, Higher Teacher Training College, University of Maroua, PO Box 46 Maroua (Cameroon); Essimbi, B Z [Department of Physics, Faculty of Science, University of Yaounde 1, PO Box 812 Yaounde (Cameroon); Jaeger, D, E-mail: bessimb@yahoo.fr [ZHO, Optoelectronik, Universitaet Duisburg-Essen, D-47048 Duisburg (Germany)

    2011-10-15

    Pulse propagation on high-frequency dissipative nonlinear transmission lines (NLTLs)/resonant tunneling diode line cascaded maps is investigated for long-distance propagation of short pulses. Applying perturbative analysis, we show that the dynamics of each line is reduced to an expanded Korteweg-de Vries-Burgers equation. Moreover, it is found by computer experiments that the soliton developed in NLTLs experiences an exponential amplitude decay on the one hand and an exponential amplitude growth on the other. As a result, the behavior of a pulse in special electrical networks made of concatenated pieces of lines is closely similar to the transmission of information in optical/electrical communication systems.

  13. Semilinear Schrödinger equations

    CERN Document Server

    Cazenave, Thierry

    2003-01-01

    The nonlinear Schrödinger equation has received a great deal of attention from mathematicians, in particular because of its applications to nonlinear optics. It is also a good model dispersive equation, since it is often technically simpler than other dispersive equations, such as the wave or Korteweg-de Vries equation. Particularly useful tools in studying the nonlinear Schrödinger equation are energy and Strichartz's estimates. This book presents various mathematical aspects of the nonlinear Schrödinger equation. It examines both problems of local nature (local existence of solutions, unique

  14. Exact solutions to the KDV-Burgers equation with forcing term using Tanh-Coth method

    Science.gov (United States)

    Chukkol, Yusuf Buba; Mohamad, Mohd Nor; Muminov, Mukhiddin I.

    2017-08-01

    In this paper, tanh-coth method was applied to derive the exact travelling wave solutions to the Korteweg-de-Vries and Burgers equation with forcing term(fKDVB). Solutions that are linear combination of solitary and shock wave solutions, and periodic wave solutions are obtained, by reducing the equation to the homogeneous type using a wave transformation. The method with the help of symbolic computation tool box provides a systematic way of solving many physical models involving nonlinear partial differential equations in mathematical physics.

  15. Nonlinear modes in the hollow-cores of liquid vortices

    KAUST Repository

    Amaouche, Mustapha

    2013-09-01

    In this paper we show that the wave patterns observed on the interfacial contours of hollow-core vortices, produced within a shallow layer of fluid contained in stationary cylinder and driven by a rotating disk at the bottom [G.H. Vatistas, H.A. Abderrahmane, M.H. Kamran Siddiqui, Experimental confirmation of Kelvin\\'s equilibria, Phys. Rev. Lett. 100 (2008) 174503-174504], can be described as travelling cnoidal waves. These rotating stationary waves are obtained as solutions of a Korteweg-de Vries type equation, in accordance with the geometrical and kinematic characteristics of the observed polygonal patterns. © 2013 Elsevier Masson SAS. All rights reserved.

  16. Persistence of solutions to nonlinear evolution equations in weighted Sobolev spaces

    Directory of Open Access Journals (Sweden)

    Xavier Carvajal Paredes

    2010-11-01

    Full Text Available In this article, we prove that the initial value problem associated with the Korteweg-de Vries equation is well-posed in weighted Sobolev spaces $mathcal{X}^{s,heta}$, for $s geq 2heta ge 2$ and the initial value problem associated with the nonlinear Schrodinger equation is well-posed in weighted Sobolev spaces $mathcal{X}^{s,heta}$, for $s geq heta geq 1$. Persistence property has been proved by approximation of the solutions and using a priori estimates.

  17. Baecklund transformations and exact solutions for Alfven solitons in a relativistic electron-positron plasma

    Energy Technology Data Exchange (ETDEWEB)

    Khater, A.H.; El-Kalaawy, O.H. [Cairo Univ., Beni-Suef (Egypt). Dept. of Mathematics; Callebaut, D.K. [Universitaire Instelling Antwerpen, Wilrijk (Belgium). Dept. of Physics

    1998-12-01

    Nonlinear Alfven waves, propagating along a homogeneous magnetic field, are studied using relativistic isotropic hydrodynamics. Alfven solitons of the moving-wave and wave packet types are considered for modified Korteweg-de Vries (mKdV) equation and the nonlinear Schroedinger (NLS) equation, respectively. The method of characteristics is used and the Baecklund transformations (BTs) are employed to generate new solutions from the old ones. Thus, families of new solutions for the mKdV and the NLS equations are obtained. The question arises which solitons exist in the pulsar atmosphere. (orig.) 37 refs.

  18. Traveling Wave Solutions of Space-Time Fractional Generalized Fifth-Order KdV Equation

    Directory of Open Access Journals (Sweden)

    Dianchen Lu

    2017-01-01

    Full Text Available The Korteweg-de Vries (KdV equation, especially the fractional higher order one, provides a relatively accurate description of motions of long waves in shallow water under gravity and wave propagation in one-dimensional nonlinear lattice. In this article, the generalized exp⁡(-Φ(ξ-expansion method is proposed to construct exact solutions of space-time fractional generalized fifth-order KdV equation with Jumarie’s modified Riemann-Liouville derivatives. At the end, three types of exact traveling wave solutions are obtained which indicate that the method is very practical and suitable for solving nonlinear fractional partial differential equations.

  19. Solution of Nonlinear Space-Time Fractional Differential Equations Using the Fractional Riccati Expansion Method

    Directory of Open Access Journals (Sweden)

    Emad A.-B. Abdel-Salam

    2013-01-01

    Full Text Available The fractional Riccati expansion method is proposed to solve fractional differential equations. To illustrate the effectiveness of the method, space-time fractional Korteweg-de Vries equation, regularized long-wave equation, Boussinesq equation, and Klein-Gordon equation are considered. As a result, abundant types of exact analytical solutions are obtained. These solutions include generalized trigonometric and hyperbolic functions solutions which may be useful for further understanding of the mechanisms of the complicated nonlinear physical phenomena and fractional differential equations. Among these solutions, some are found for the first time. The periodic and kink solutions are founded as special case.

  20. Dust-acoustic shock waves in a charge varying electronegative magnetized dusty plasma with nonthermal ions: Application to Halley Comet plasma

    Energy Technology Data Exchange (ETDEWEB)

    Tribeche, Mouloud; Bacha, Mustapha [Plasma Physics Group (PPG), Theoretical Physics Laboratory (TPL), Faculty of Physics, University of Bab-Ezzouar, USTHB, B. P. 32, El Alia, Algiers 16111 (Algeria)

    2013-10-15

    Weak dust-acoustic waves (DAWs) are addressed in a nonthermal charge varying electronegative magnetized dusty plasmas with application to the Halley Comet. A weakly nonlinear analysis is carried out to derive a Korteweg-de Vries-Burger equation. The positive ion nonthermality, the obliqueness, and magnitude of the magnetic field are found to modify the dispersive and dissipative properties of the DA shock structure. Our results may aid to explain and interpret the nonlinear oscillations that may occur in the Halley Comet Plasma.

  1. Nonholonomic deformation of KdV and mKdV equations and their symmetries, hierarchies and integrability

    Energy Technology Data Exchange (ETDEWEB)

    Kundu, Anjan [Theory Group and CAMCS, Saha Institute of Nuclear Physics, Calcutta (India); Sahadevan, R; Nalinidevi, L [Ramanujan Institute for Advanced Study in Mathematics, University of Madras, Chennai 600 005, Tamilnadu (India)], E-mail: anjan.kundu@saha.ac.in, E-mail: ramajayamsaha@yahoo.co.in, E-mail: lnalinidevi@yahoo.co.in

    2009-03-20

    The recent concept of integrable nonholonomic deformation found for the Korteweg-de Vries (KdV) equation is extended to the modified KdV (mKdV) equation and generalized to the AKNS system. For the deformed mKdV equation we find a matrix Lax pair, a novel two-fold integrable hierarchy and exact N-soliton solutions exhibiting unusual accelerating motion. We show that both the deformed KdV and mKdV systems possess infinitely many generalized symmetries, conserved quantities and a recursion operator.

  2. The variational iteration method and the variational homotopy perturbation method for solving the KdV-Burgers equation and the Sharma-Tasso-Olver equation

    Energy Technology Data Exchange (ETDEWEB)

    Zayed, Elsayed M.E. [Dept. of Mathematics, Zagazig Univ. (Egypt); Abdel Rahman, Hanan M. [Dept. of Basic Sciences, Higher Technological Inst., Tenth of Ramadan City (Egypt)

    2010-01-15

    In this article, two powerful analytical methods called the variational iteration method (VIM) and the variational homotopy perturbation method (VHPM) are introduced to obtain the exact and the numerical solutions of the (2+1)-dimensional Korteweg-de Vries-Burgers (KdVB) equation and the (1+1)-dimensional Sharma-Tasso-Olver equation. The main objective of the present article is to propose alternative methods of solutions, which avoid linearization and physical unrealistic assumptions. The results show that these methods are very efficient, convenient and can be applied to a large class of nonlinear problems. (orig.)

  3. Exact periodic cross-kink wave solutions for the new (2+1)-dimensional KdV equation in fluid flows and plasma physics.

    Science.gov (United States)

    Liu, Jian-Guo; Du, Jian-Qiang; Zeng, Zhi-Fang; Ai, Guo-Ping

    2016-10-01

    The Korteweg-de Vries (KdV)-type models have been shown to describe many important physical situations such as fluid flows, plasma physics, and solid state physics. In this paper, a new (2 + 1)-dimensional KdV equation is discussed. Based on the Hirota's bilinear form and a generalized three-wave approach, we obtain new exact solutions for the new (2 + 1)-dimensional KdV equation. With the help of symbolic computation, the properties for some new solutions are presented with some figures.

  4. Estudio de las ecuaciones de Boussinesq para la modelización de tsunamis

    OpenAIRE

    Andia García, Patricia

    2016-01-01

    [es]Podemos encontrar las ecuaciones de Boussinesq en la descripción de playas, rios y lagos. Estas ecuaciones estudian la dinámica de las aguas poco profundas como las ecuaciones “ Korteweg-deVries (KdV)". Sin embargo, a pesar de ser más conocidas, las ecuaciones de KdV, no son capaces de modelar olas solitarias propagándose en distintas direcciones. Entre muchas otras aplicaciones de las ecuaciones de Boussinesq destaca la de modelar olas de tsunamis. Estos tipos de olas ya son perfectament...

  5. Soliton equations and Hamiltonian systems

    CERN Document Server

    Dickey, L A

    2002-01-01

    The theory of soliton equations and integrable systems has developed rapidly during the last 30 years with numerous applications in mechanics and physics. For a long time, books in this field have not been written but the flood of papers was overwhelming: many hundreds, maybe thousands of them. All this output followed one single work by Gardner, Green, Kruskal, and Mizura on the Korteweg-de Vries equation (KdV), which had seemed to be merely an unassuming equation of mathematical physics describing waves in shallow water. Besides its obvious practical use, this theory is attractive also becau

  6. El Naschie's Cantorian space time, Toda lattices and Cooper-Agop pairs

    CERN Document Server

    Gottlieb, I; Buzea, C G

    2003-01-01

    We show that space time-matter connection works like a quasiautonomous structure by means of cnoidal oscillation modes. Identifying the cnoidal oscillation modes with one-dimensional Toda lattice, by its nonlinear mode works, on the acoustic branch of the phononic spectrum, generalized Cooper pairs ('Cooper-Agop pairs') are induced. In such a context the fractal characteristic is given by redefining a coefficient in a Korteweg-de Vries (KdV) type equation, and the Cantorian structure are assimilated with two coupled oscillator like in the simple mechanical model of El Naschie's epsilon sup ( supinfinity sup ) theory.

  7. A composite Runge-Kutta method for the spectral solution of semilinear PDEs

    CERN Document Server

    Driscoll, T A

    2002-01-01

    A new composite Runge-Kutta (RK) method is proposed for semilinear partial differential equations such as Korteweg-de Vries, nonlinear Schroedinger, Kadomtsev-Petviashvili (KP), Kuramoto-Sivashinsky (KS), Cahn-Hilliard, and others having high-order derivatives in the linear term. The method uses Fourier collocation and the classical fourth-order RK method, except for the stiff linear modes, which are treated with a linearly implicit RK method. The composite RK method is simple to implement, indifferent to the distinction between dispersive and dissipative problems, and as efficient on test problems for KS and KP as any other generally applicable method.

  8. Nonlinear-dispersive mechanism of the freak wave formation in shallow water

    Science.gov (United States)

    Pelinovsky, Efim; Talipova, Tatiana; Kharif, Christian

    2000-12-01

    The mechanism of the freak wave formation related to the spatial-temporal focusing is studied within the framework of the Korteweg-de Vries equation. A method to find the wave trains whose evolution leads to the freak wave formation is proposed. It is based on the solution of the Korteweg-de Vries equation with an initial condition corresponding to the expected freak wave. All solutions of this Cauchy problem by the reversal of abscissa represent the possible forms of wave trains which evolve into the freak wave. It is found that freak waves are almost linear waves, and their characteristic Ursell parameter is small. The freak wave formation is possible also from the random wave field and the numerical simulation describes the details of this phenomenon. It is shown that freak waves can be generated not only for specific conditions, but also for relative wide classes of the wave trains. This mechanism explains the rare and short-lived character of the freak wave.

  9. An inverse scattering transform for the lattice potential KdV equation

    Science.gov (United States)

    Butler, Samuel; Joshi, Nalini

    2010-11-01

    The lattice potential Korteweg-de Vries equation (LKdV) is a partial difference equation in two independent variables, which possesses many properties that are analogous to those of the celebrated Korteweg-de Vries equation. These include discrete soliton solutions, Bäcklund transformations and an associated linear problem, called a Lax pair, for which it provides the compatibility condition. In this paper, we solve the initial value problem for the LKdV equation through a discrete implementation of the inverse scattering transform method applied to the Lax pair. The initial value used for the LKdV equation is assumed to be real and decaying to zero as the absolute value of the discrete spatial variable approaches large values. An interesting feature of our approach is the solution of a discrete Gel'fand-Levitan equation. Moreover, we provide a complete characterization of reflectionless potentials and show that this leads to the Cauchy matrix form of N-soliton solutions.

  10. A Riemann-Hilbert Approach for the Novikov Equation

    Science.gov (United States)

    Boutet de Monvel, Anne; Shepelsky, Dmitry; Zielinski, Lech

    2016-09-01

    We develop the inverse scattering transform method for the Novikov equation u_t-u_{txx}+4u^2u_x=3u u_xu_{xx}+u^2u_{xxx} considered on the line xin(-∞,∞) in the case of non-zero constant background. The approach is based on the analysis of an associated Riemann-Hilbert (RH) problem, which in this case is a 3× 3 matrix problem. The structure of this RH problem shares many common features with the case of the Degasperis-Procesi (DP) equation having quadratic nonlinear terms (see [Boutet de Monvel A., Shepelsky D., Nonlinearity 26 (2013), 2081-2107, arXiv:1107.5995]) and thus the Novikov equation can be viewed as a ''modified DP equation'', in analogy with the relationship between the Korteweg-de Vries (KdV) equation and the modified Korteweg-de Vries (mKdV) equation. We present parametric formulas giving the solution of the Cauchy problem for the Novikov equation in terms of the solution of the RH problem and discuss the possibilities to use the developed formalism for further studying of the Novikov equation.

  11. Painlevé analysis and some solutions of variable coefficient Benny ...

    Indian Academy of Sciences (India)

    Pramana – Journal of Physics. Current Issue : Vol. 89, Issue 6 · Current Issue Volume 89 | Issue 6. December 2017. Home · Volumes & Issues · Special Issues · Forthcoming Articles · Search · Editorial Board · Information for Authors · Subscription ...

  12. Existence of Positive Solution for a Fourth-order Differential System with Variable Coefficients

    Directory of Open Access Journals (Sweden)

    Béla Kovács

    2015-06-01

    Full Text Available This paper investigates the existence of positive solutions for a fourth-order differential system using a fixed point theorem of cone expansion and compression type. The two main results give sufficient conditions to insure at least one and at least two positive solutions, respectively

  13. Almost monotonicity formulas for elliptic and parabolic operators with variable coefficients

    KAUST Repository

    Matevosyan, Norayr

    2010-10-21

    In this paper we extend the results of Caffarelli, Jerison, and Kenig [Ann. of Math. (2)155 (2002)] and Caffarelli and Kenig [Amer. J. Math.120 (1998)] by establishing an almost monotonicity estimate for pairs of continuous functions satisfying u± ≥ 0 Lu± ≥ -1, u+ · u_ = 0 ;in an infinite strip (global version) or a finite parabolic cylinder (localized version), where L is a uniformly parabolic operator Lu = LA,b,cu := div(A(x, s)∇u) + b(x,s) · ∇u + c(x,s)u - δsu with double Dini continuous A and uniformly bounded b and c. We also prove the elliptic counterpart of this estimate.This closes the gap between the known conditions in the literature (both in the elliptic and parabolic case) imposed on u± in order to obtain an almost monotonicity estimate.At the end of the paper, we demonstrate how to use this new almost monotonicity formula to prove the optimal C1,1-regularity in a fairly general class of quasi-linear obstacle-type free boundary problems. © 2010 Wiley Periodicals, Inc.

  14. Analytic Approximation of Solutions of Parabolic Partial Differential Equations with Variable Coefficients

    Directory of Open Access Journals (Sweden)

    Vladislav V. Kravchenko

    2017-01-01

    Full Text Available A complete family of solutions for the one-dimensional reaction-diffusion equation, uxx(x,t-q(xu(x,t=ut(x,t, with a coefficient q depending on x is constructed. The solutions represent the images of the heat polynomials under the action of a transmutation operator. Their use allows one to obtain an explicit solution of the noncharacteristic Cauchy problem with sufficiently regular Cauchy data as well as to solve numerically initial boundary value problems. In the paper, the Dirichlet boundary conditions are considered; however, the proposed method can be easily extended onto other standard boundary conditions. The proposed numerical method is shown to reveal good accuracy.

  15. Langevin Dynamics with Variable Coefficients and Nonconservative Forces: From Stationary States to Numerical Methods

    Directory of Open Access Journals (Sweden)

    Matthias Sachs

    2017-11-01

    Full Text Available Langevin dynamics is a versatile stochastic model used in biology, chemistry, engineering, physics and computer science. Traditionally, in thermal equilibrium, one assumes (i the forces are given as the gradient of a potential and (ii a fluctuation-dissipation relation holds between stochastic and dissipative forces; these assumptions ensure that the system samples a prescribed invariant Gibbs-Boltzmann distribution for a specified target temperature. In this article, we relax these assumptions, incorporating variable friction and temperature parameters and allowing nonconservative force fields, for which the form of the stationary state is typically not known a priori. We examine theoretical issues such as stability of the steady state and ergodic properties, as well as practical aspects such as the design of numerical methods for stochastic particle models. Applications to nonequilibrium systems with thermal gradients and active particles are discussed.

  16. symmetric generalized Korteweg–de Vries equations

    Indian Academy of Sciences (India)

    5Theoretical Division and Center for Nonlinear Studies, Los Alamos National Laboratory,. Los Alamos, NM 87545, USA ... Compactons; PT symmetry; generalized KdV equations. PACS Nos 03.65.Ge; 02.60. ... This system of equations has three obvious conservation laws: conservation of mass M, momentum P and energy ...

  17. Electron acoustic solitary waves in a magnetized plasma with nonthermal electrons and an electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Singh, S. V., E-mail: satyavir@iigs.iigm.res.in; Lakhina, G. S., E-mail: lakhina@iigs.iigm.res.in [Indian Institute of Geomagnetism, New Panvel (W), Navi Mumbai (India); University of the Western Cape, Belville (South Africa); Devanandhan, S., E-mail: devanandhan@gmail.com [Indian Institute of Geomagnetism, New Panvel (W), Navi Mumbai (India); Bharuthram, R., E-mail: rbharuthram@uwc.ac.za [University of the Western Cape, Belville (South Africa)

    2016-08-15

    A theoretical investigation is carried out to study the obliquely propagating electron acoustic solitary waves having nonthermal hot electrons, cold and beam electrons, and ions in a magnetized plasma. We have employed reductive perturbation theory to derive the Korteweg-de-Vries-Zakharov-Kuznetsov (KdV-ZK) equation describing the nonlinear evolution of these waves. The two-dimensional plane wave solution of KdV-ZK equation is analyzed to study the effects of nonthermal and beam electrons on the characteristics of the solitons. Theoretical results predict negative potential solitary structures. We emphasize that the inclusion of finite temperature effects reduces the soliton amplitudes and the width of the solitons increases by an increase in the obliquity of the wave propagation. The numerical analysis is presented for the parameters corresponding to the observations of “burst a” event by Viking satellite on the auroral field lines.

  18. Spectral stability of undercompressive shock profile solutions of a modified KdV-Burgers equation

    Directory of Open Access Journals (Sweden)

    Jeff Dodd

    2007-10-01

    Full Text Available It is shown that certain undercompressive shock profile solutions of the modified Korteweg-de Vries-Burgers equation $$ partial_t u + partial_x(u^3 = partial_x^3 u + alpha partial_x^2 u, quad alpha geq 0 $$ are spectrally stable when $alpha$ is sufficiently small, in the sense that their linearized perturbation equations admit no eigenvalues having positive real part except a simple eigenvalue of zero (due to the translation invariance of the linearized perturbation equations. This spectral stability makes it possible to apply a theory of Howard and Zumbrun to immediately deduce the asymptotic orbital stability of these undercompressive shock profiles when $alpha$ is sufficiently small and positive.

  19. A numerical dressing method for the nonlinear superposition of solutions of the KdV equation

    Science.gov (United States)

    Trogdon, Thomas; Deconinck, Bernard

    2014-01-01

    In this paper we present the unification of two existing numerical methods for the construction of solutions of the Korteweg-de Vries (KdV) equation. The first method is used to solve the Cauchy initial-value problem on the line for rapidly decaying initial data. The second method is used to compute finite-genus solutions of the KdV equation. The combination of these numerical methods allows for the computation of exact solutions that are asymptotically (quasi-)periodic finite-gap solutions and are a nonlinear superposition of dispersive, soliton and (quasi-)periodic solutions in the finite (x, t)-plane. Such solutions are referred to as superposition solutions. We compute these solutions accurately for all values of x and t.

  20. Inverse scattering transform for the integrable nonlocal nonlinear Schrödinger equation

    Science.gov (United States)

    Ablowitz, Mark J.; Musslimani, Ziad H.

    2016-03-01

    A nonlocal nonlinear Schrödinger (NLS) equation was recently introduced and shown to be an integrable infinite dimensional Hamiltonian evolution equation. In this paper a detailed study of the inverse scattering transform of this nonlocal NLS equation is carried out. The direct and inverse scattering problems are analyzed. Key symmetries of the eigenfunctions and scattering data and conserved quantities are obtained. The inverse scattering theory is developed by using a novel left-right Riemann-Hilbert problem. The Cauchy problem for the nonlocal NLS equation is formulated and methods to find pure soliton solutions are presented; this leads to explicit time-periodic one and two soliton solutions. A detailed comparison with the classical NLS equation is given and brief remarks about nonlocal versions of the modified Korteweg-de Vries and sine-Gordon equations are made.

  1. Oscillatory integrals generated by the Ostrovsky equation

    Science.gov (United States)

    Varlamov, Vladimir

    2005-11-01

    The Ostrovsky equation governs the propagation of long nonlinear surface waves in the presence of rotation. It is related to the Korteweg-de Vries (KdV) and the Kadomtsev-Petviashvili models. KdV can be obtained from the equation in question when the rotation parameter γ equals zero. A fundamental solution of the Cauchy problem for the linear Ostrovsky equation is presented in the form of an oscillatory Fourier integral. Another integral representation involving Airy and Bessel functions is derived for it. It is shown that its asymptotic expansion as γ → 0 contains the KdV fundamental solution as the zero term. The Airy transform is used to establish some of its properties. Higher-order asymptotics for γ → 0 on a bounded time interval are obtained for both the fundamental solution and the solution of the linear Cauchy problem for the Ostrovsky equation.

  2. Well-posedness for the Cauchy problem associated to the Hirota-Satsuma equation: Periodic case

    Science.gov (United States)

    Panthee, Mahendra; Silva, Jorge Drumond

    2007-02-01

    We consider a system of Korteweg-de Vries (KdV) equations coupled through nonlinear terms, called the Hirota-Satsuma system. We study the initial value problem (IVP) associated to this system in the periodic case, for given data in Sobolev spaces HsxHs+1 with regularity below the one given by the conservation laws. Using the Fourier transform restriction norm method, we prove local well-posedness whenever s>-1/2. Also, with some restriction on the parameters of the system, we use the recent technique introduced by Colliander et al., called I-method and almost conserved quantities, to prove global well-posedness for s>-3/14.

  3. New direct linearizations for KdV and solutions of the other Cauchy problem

    Science.gov (United States)

    Sabatier, Pierre C.

    1999-06-01

    The author showed previously that there are several equations that "directly linearize" the Korteweg de Vries equation. They may give different classes of solutions and they correspond either to generalized Gelfand Levitan or generalized Marchenko inversion equations. The idea is developed here with a precise goal: solving by linear methods the "other Cauchy problem" for KdV, i.e., the boundary value problem where the solution is known at fixed x, together with its two first derivatives. After several new direct linearization equations are given and analyzed, the one that solves the problem is eventually obtained. It also corresponds to a new inverse spectral problem, whose scalar equations are fourth order, and that is first studied in the Gelfand Levitan form, and then studied and completely solved in the Marchenko form. The methods given here can be extended probably to most nonlinear integrable equations, and suggest several new problems.

  4. Universality of the Break-up Profile for the KdV Equation in the Small Dispersion Limit Using the Riemann-Hilbert Approach

    Science.gov (United States)

    Claeys, T.; Grava, T.

    2009-03-01

    We obtain an asymptotic expansion for the solution of the Cauchy problem for the Korteweg-de Vries (KdV) equation u_t+6uu_x+ɛ2u_{xxx}=0,quad u(x,t=0,ɛ)=u_0(x), for {ɛ} small, near the point of gradient catastrophe ( x c , t c ) for the solution of the dispersionless equation u t + 6 uu x = 0. The sub-leading term in this expansion is described by the smooth solution of a fourth order ODE, which is a higher order analogue to the Painlevé I equation. This is in accordance with a conjecture of Dubrovin, suggesting that this is a universal phenomenon for any Hamiltonian perturbation of a hyperbolic equation. Using the Deift/Zhou steepest descent method applied on the Riemann-Hilbert problem for the KdV equation, we are able to prove the asymptotic expansion rigorously in a double scaling limit.

  5. On Whitham Equations for Camassa-Holm

    Science.gov (United States)

    Abenda, S.; Grava, T.; Klein, C.

    2006-03-01

    The solution of the Cauchy problem for the Camassa-Holm equation φt + 3φφx = ɛ2(φxxt + 2φxφxx + φφxxx) - 2νφx, in the limit ɛ → 0 is characterized by a zone of rapid modulated oscillations. This situation is very similar to solution of the Korteweg de Vries equation in the small dispersion limit. In this latter case the modulated oscillations are known to be approximately described by the Whitham equations. The analogous problem is, on the contrary, still open in the case of the Camassa-Holm equation. In this paper, we present some preliminary work in the direction of numerically compare the solution to the Cauchy problem of the Camassa-Holm equation in the limit ɛ → 0 and the approximate solution which should be described by the corresponding Whitham equations.

  6. Nonlinear dynamics and chaotic phenomena an introduction

    CERN Document Server

    Shivamoggi, Bhimsen K

    2014-01-01

    This book starts with a discussion of nonlinear ordinary differential equations, bifurcation theory and Hamiltonian dynamics. It then embarks on a systematic discussion of the traditional topics of modern nonlinear dynamics  -- integrable systems, Poincaré maps, chaos, fractals and strange attractors. The Baker’s transformation, the logistic map and Lorenz system are discussed in detail in view of their central place in the subject. There is a detailed discussion of solitons centered around the Korteweg-deVries equation in view of its central place in integrable systems. Then, there is a discussion of the Painlevé property of nonlinear differential equations which seems to provide a test of integrability. Finally, there is a detailed discussion of the application of fractals and multi-fractals to fully-developed turbulence -- a problem whose understanding has been considerably enriched by the application of the concepts and methods of modern nonlinear dynamics. On the application side, there is a special...

  7. Analysis of driver's characteristics on a curved road in a lattice model

    Science.gov (United States)

    Kaur, Ramanpreet; Sharma, Sapna

    2017-04-01

    The present paper investigates the effect of driver's behavior on the curved road via lattice hydrodynamic approach. The basic model for straight road is extended for the curved road and the characteristics of driver's behavior is incorporated in the lattice model. The extended model is investigated theoretically by the means of linear stability analysis and the effect of curved road and intensity of influence of driver's behavior on the traffic flow stability is examined. Through nonlinear stability analysis, the modified Korteweg-de Vries (MKdV) equation near the critical point is derived to describe the evolution properties of traffic density waves by applying the reductive perturbation method. Furthermore, the numerical simulation is carried out to validate the theoretical results which indicates that the curved road has a negative influence on the stability of the traffic flow. It is also seen that the traffic jam on a curved road can be suppressed efficiently via taking into account aggressive drivers.

  8. Time-dependent cylindrical and spherical ion-acoustic solitary structures in relativistic degenerate multi-ion plasmas with positively-charged heavy ions

    Science.gov (United States)

    Hossen, M. R.; Nahar, L.; Mamun, A. A.

    2014-12-01

    The properties of time-dependent cylindrical and spherical, modified ion-acoustic (mIA) solitary structures in relativistic degenerate multi-ion plasmas (containing degenerate electron fluids, inertial positively-, as well as negatively-, charged light ions, and positively-charged static heavy ions) have been investigated theoretically. This investigation is valid for both non-relativistic and ultra-relativistic limits. The well-known reductive perturbation method has been used to derive the Korteweg-de Vries (K-dV) and the mK-dV equations for studying the basic features of solitary waves. The fundamental characteristics of mIA solitary waves are found to be significantly modified by the effects of the degenerate pressures of the electron and the ion fluids, their number densities, and the various charge states of heavy ions. The relevance of our results in astrophysical compact objects like white dwarfs and neutron stars, which are of scientific interest, is briefly discussed.

  9. Radiation by solitons due to higher-order dispersion

    DEFF Research Database (Denmark)

    Karpman, V.I.

    1993-01-01

    in a simple and general way the radiation of KdV and NS, as well as other types. of solitons, is developed. From the WKB approach it follows that the soliton radiation is a result of a tunneling transformation of the non-linearly self-trapped wave into the free-propagating radiation.......We consider the Korteweg-de Vries (KdV) and nonlinear Schrodinger (NS) equations with higher-order derivative terms describing dispersive corrections. Conditions of existence of stationary and radiating solitons of the fifth-order KdV equation are obtained. An asymptotic time-dependent solution...... to the latter equation, describing the soliton radiation, is found. The radiation train may be in front as well as behind the soliton, depending on the sign of dispersion. The change rate of the soliton due to the radiation is calculated. A modification of the WKB method, that permits one to describe...

  10. Numerical solutions and solitary wave solutions of fractional KDV equations using modified fractional reduced differential transform method

    Science.gov (United States)

    Saha Ray, S.

    2013-12-01

    In this paper, the modified fractional reduced differential transform method (MFRDTM) has been proposed and it is implemented for solving fractional KdV (Korteweg-de Vries) equations. The fractional derivatives are described in the Caputo sense. In this paper, the reduced differential transform method is modified to be easily employed to solve wide kinds of nonlinear fractional differential equations. In this new approach, the nonlinear term is replaced by its Adomian polynomials. Thus the nonlinear initial-value problem can be easily solved with less computational effort. In order to show the power and effectiveness of the present modified method and to illustrate the pertinent features of the solutions, several fractional KdV equations with different types of nonlinearities are considered. The results reveal that the proposed method is very effective and simple for obtaining approximate solutions of fractional KdV equations.

  11. Influence of ionization on reflection of solitary waves in a magnetized plasma

    Science.gov (United States)

    Jyoti; Kumar, Ravinder; Malik, Hitendra K.; Dahiya, Raj P.

    2013-09-01

    The reflection of nonlinear solitary waves is studied in a nonuniform, magnetized plasma diffusing from an ionization source along the magnetic field lines. Contribution of the ionization term is included in the continuity equation. The behavior of solitary waves is governed by modified form of Korteweg-de Vries equation (called mKdV equation). In order to investigate the reflection of solitary waves, the mKdV equations for the right and left going waves are derived, and solved by finding new transformations coupled at the point of reflection, for obtaining the expression of reflection coefficient. Contrary to the case of usual inhomogeneous plasma, the present analysis shows that a combination of usual sech2 structure and tanh structure (called the tail of soliton) arises due to the influence of ionization term. Interestingly, this tailing structure disappears after the reflection of the soliton and hence, the soliton is downshifted prominently.

  12. On radiating solitary waves in bi-layers with delamination and coupled Ostrovsky equations.

    Science.gov (United States)

    Khusnutdinova, K R; Tranter, M R

    2017-01-01

    We study the scattering of a long longitudinal radiating bulk strain solitary wave in the delaminated area of a two-layered elastic structure with soft ("imperfect") bonding between the layers within the scope of the coupled Boussinesq equations. The direct numerical modelling of this and similar problems is challenging and has natural limitations. We develop a semi-analytical approach, based on the use of several matched asymptotic multiple-scale expansions and averaging with respect to the fast space variable, leading to the coupled Ostrovsky equations in bonded regions and uncoupled Korteweg-de Vries equations in the delaminated region. We show that the semi-analytical approach agrees well with direct numerical simulations and use it to study the nonlinear dynamics and scattering of the radiating solitary wave in a wide range of bi-layers with delamination. The results indicate that radiating solitary waves could help us to control the integrity of layered structures with imperfect interfaces.

  13. Brief communication: Multiscaled solitary waves

    Science.gov (United States)

    Derzho, Oleg G.

    2017-11-01

    It is analytically shown how competing nonlinearities yield multiscaled structures for internal solitary waves in stratified shallow fluids. These solitary waves only exist for large amplitudes beyond the limit of applicability of the Korteweg-de Vries (KdV) equation or its usual extensions. The multiscaling phenomenon exists or does not exist for almost identical density profiles. The trapped core inside the wave prevents the appearance of such multiple scales within the core area. The structural stability of waves of large amplitudes is briefly discussed. Waves of large amplitudes displaying quadratic, cubic and higher-order nonlinear terms have stable and unstable branches. Multiscaled waves without a vortex core are shown to be structurally unstable. It is anticipated that multiscaling phenomena will exist for solitary waves in various physical contexts.

  14. Face-to-face interaction of multisolitons in spin-1/2 quantum plasma

    Science.gov (United States)

    Roy, Kaushik; Choudhury, Sourav; Chatterjee, Prasanta; Wong, C. S.

    2017-01-01

    We investigate the face-to-face collision between multisolitons in spin-1/2 quantum plasma. It is studied in the framework of the model proposed by Marklund et al in Phys. Rev. E 76, 067401 (2007). This study is done with the help of the extended Poincare-Lighthill-Kno (PLK) method. The extended PLK method is also used to obtain two Korteweg-de Vries (KdV) equations and the phase shifts and trajectories during the head-on collision of multisolitons. The collision-induced phase shifts (trajectory changes) are also obtained. The effects of the Zeeman energy, total mass density of the charged plasma particles, speed of the wave and the ratio of the sound speed to Alfvén speed on the phase shifts are studied. It is observed that the phase shifts are significantly affected by all these parameters.

  15. Global well-posedness of NLS-KdV systems for periodic functions

    Directory of Open Access Journals (Sweden)

    Carlos Matheus

    2007-01-01

    Full Text Available We prove that the Cauchy problem of the Schrodinger-Korteweg-deVries (NLS-KdV system for periodic functions is globally well-posed for initial data in the energy space $H^1imes H^1$. More precisely, we show that the non-resonant NLS-KdV system is globally well-posed for initial data in $H^s(mathbb{T}imes H^s(mathbb{T}$ with $s>11/13$ and the resonant NLS-KdV system is globally well-posed with $s>8/9$. The strategy is to apply the I-method used by Colliander, Keel, Staffilani, Takaoka and Tao. By doing this, we improve the results by Arbieto, Corcho and Matheus concerning the global well-posedness of NLS-KdV systems.

  16. Dissipative dust-acoustic shock waves in a varying charge electronegative magnetized dusty plasma with trapped electrons

    Energy Technology Data Exchange (ETDEWEB)

    Bacha, Mustapha [Faculty of Physics, Theoretical Physics Laboratory, Plasma Physics Group, University of Bab-Ezzouar, USTHB, B.P. 32, El Alia, Algiers 16111 (Algeria); Tribeche, Mouloud, E-mail: mouloudtribeche@yahoo.fr, E-mail: mtribeche@usthb.dz [Faculty of Physics, Theoretical Physics Laboratory, Plasma Physics Group, University of Bab-Ezzouar, USTHB, B.P. 32, El Alia, Algiers 16111 (Algeria); Algerian Academy of Sciences and Technologies, Algiers (Algeria)

    2016-08-15

    The combined effects of an oblique magnetic field and electron trapping on dissipative dust-acoustic waves are examined in varying charge electronegative dusty plasmas with application to the Halley Comet plasma (∼10{sup 4} km from the nucleus). A weakly nonlinear analysis is carried out to derive a modified Korteweg-de Vries-Burger-like equation. Making use of the equilibrium current balance equation, the physically admissible values of the electron trapping parameter are first constrained. We then show that the Burger dissipative term is solely due to the dust charge variation process. It is found that an increase of the magnetic field obliqueness or a decrease of its magnitude renders the shock structure more dispersive.

  17. Spontaneous symmetry breaking and neutral stability in the noncanonical Hamiltonian formalism

    Energy Technology Data Exchange (ETDEWEB)

    Morrison, P.J.; Eliezer, S.

    1985-10-01

    The noncanonical Hamiltonian formalism is based upon a generalization of the Poisson bracket, a particular form of which is possessed by continuous media fields. Associated with this generalization are special constants of motion called Casimirs. These are constants that can be viewed as being built into the phase space, for they are invariant for all Hamiltonians. Casimirs are important because when added to the Hamiltonian they yield an effective Hamiltonian that produces equilibrium states upon variation. The stability of these states can be ascertained by a second variation. Goldstone's theorem, in its usual context, determines zero eigenvalues of the mass matrix for a given vacuum state, the equilibrium with minimum energy. Here, since for fluids and plasmas the vacuum state is uninteresting, we examine symmetry breaking for general equilibria. Broken symmetries imply directions of neutral stability. Two examples are presented: the nonlinear Alfven wave of plasma physics and the Korteweg-de Vries soliton. 46 refs.

  18. Spontaneous symmetry breaking and neutral stability in the noncanonical Hamiltonian formalism

    Energy Technology Data Exchange (ETDEWEB)

    Morrison, P.J.; Eliezer, S.

    1986-06-01

    The noncanonical Hamiltonian formalism is based upon a generalization of the Poisson bracket, a particular form of which is possessed by continuous media fields. Associated with this generalization are special constants of motion called Casimir invariants. These are constants that can be viewed as being built into the phase space, for they are invariant for all Hamiltonians. Casimir invariants are important because when added to the Hamiltonian they yield an effective Hamiltonian that produces equilibrium states upon variation. The stability of these states can be ascertained by a second variation. Goldstone's theorem, in its usual context, determines zero eigenvalues of the mass matrix for a given vacuum state, the equilibrium with minimum energy. Here, since for fluids and plasmas the vacuum state is uninteresting, we examine symmetry breaking for general equilibria. Broken symmetries imply directions of neutral stability. Two examples are presented: the nonlinear Alfven wave of plasma physics and the Korteweg-de Vries soliton.

  19. Shallow water cnoidal wave interactions

    Directory of Open Access Journals (Sweden)

    A. R. Osborne

    1994-01-01

    Full Text Available The nonlinear dynamics of cnoidal waves, within the context of the general N-cnoidal wave solutions of the periodic Korteweg-de Vries (KdV and Kadomtsev-Petvishvilli (KP equations, are considered. These equations are important for describing the propagation of small-but-finite amplitude waves in shallow water; the solutions to KdV are unidirectional while those of KP are directionally spread. Herein solutions are constructed from the 0-function representation of their appropriate inverse scattering transform formulations. To this end a general theorem is employed in the construction process: All solutions to the KdV and KP equations can be written as the linear superposition of cnoidal waves plus their nonlinear interactions. The approach presented here is viewed as significant because it allows the exact construction of N degree-of-freedom cnoidal wave trains under rather general conditions.

  20. Nonlinear PDEs a dynamical systems approach

    CERN Document Server

    Schneider, Guido

    2017-01-01

    This is an introductory textbook about nonlinear dynamics of PDEs, with a focus on problems over unbounded domains and modulation equations. The presentation is example-oriented, and new mathematical tools are developed step by step, giving insight into some important classes of nonlinear PDEs and nonlinear dynamics phenomena which may occur in PDEs. The book consists of four parts. Parts I and II are introductions to finite- and infinite-dimensional dynamics defined by ODEs and by PDEs over bounded domains, respectively, including the basics of bifurcation and attractor theory. Part III introduces PDEs on the real line, including the Korteweg-de Vries equation, the Nonlinear Schrödinger equation and the Ginzburg-Landau equation. These examples often occur as simplest possible models, namely as amplitude or modulation equations, for some real world phenomena such as nonlinear waves and pattern formation. Part IV explores in more detail the connections between such complicated physical systems and the reduced...

  1. Effects of distinct ion temperatures on the head-on collision and phase shifts of dust acoustic one and multi-solitons in dusty plasmas

    CERN Document Server

    Alam, M S; Talukder, M R; Ali, M Hossain

    2016-01-01

    The propagation characteristics and interactions between the dust acoustic (DA) one and multi solitons in an unmagnetized dusty plasmas composing negatively charged mobile dust, Boltzmann distributed electrons, nonextensive distributed cold and nonthermal distributed hot ions are studied. The well known extended Poincar Lighthill Kuo (PLK) method is employed to derive the two sided Korteweg de Vries (KdV) equations. The solutions of KdV equations are constructed using the Hirota method both for one and multi solitons. The phase shifts are determined for the interaction of one, two and three DA solitons. The effects of plasma parameters on the head on collision of DA one as well as multi solitons and their corresponding phase shifts are investigated.

  2. Optimal boundary control and boundary stabilization of hyperbolic systems

    CERN Document Server

    Gugat, Martin

    2015-01-01

    This brief considers recent results on optimal control and stabilization of systems governed by hyperbolic partial differential equations, specifically those in which the control action takes place at the boundary.  The wave equation is used as a typical example of a linear system, through which the author explores initial boundary value problems, concepts of exact controllability, optimal exact control, and boundary stabilization.  Nonlinear systems are also covered, with the Korteweg-de Vries and Burgers Equations serving as standard examples.  To keep the presentation as accessible as possible, the author uses the case of a system with a state that is defined on a finite space interval, so that there are only two boundary points where the system can be controlled.  Graduate and post-graduate students as well as researchers in the field will find this to be an accessible introduction to problems of optimal control and stabilization.

  3. Nonlinear Waveforms for Ion-Acoustic Waves in Weakly Relativistic Plasma of Warm Ion-Fluid and Isothermal Electrons

    Directory of Open Access Journals (Sweden)

    S. A. El-Wakil

    2012-01-01

    Full Text Available The reductive perturbation method has been employed to derive the Korteweg-de Vries (KdV equation for small- but finite-amplitude electrostatic ion-acoustic waves in weakly relativistic plasma consisting of warm ions and isothermal electrons. An algebraic method with computerized symbolic computation is applied in obtaining a series of exact solutions of the KdV equation. Numerical studies have been made using plasma parameters which reveal different solutions, that is, bell-shaped solitary pulses, rational pulses, and solutions with singularity at finite points, which called “blowup” solutions in addition to the propagation of an explosive pulses. The weakly relativistic effect is found to significantly change the basic properties (namely, the amplitude and the width of the ion-acoustic waves. The result of the present investigation may be applicable to some plasma environments, such as ionosphere region.

  4. Observation of dust acoustic shock wave in a strongly coupled dusty plasma

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Sumita K., E-mail: sumita-sharma82@yahoo.com; Boruah, A.; Nakamura, Y.; Bailung, H., E-mail: hbailung@yahoo.com [Physical Sciences Division, Institute of Advanced Study in Science and Technology, Guwahati 781035 (India)

    2016-05-15

    Dust acoustic shock wave is observed in a strongly coupled laboratory dusty plasma. A supersonic flow of charged microparticles is allowed to perturb a stationary dust fluid to excite dust acoustic shock wave. The evolution process beginning with steepening of initial wave front and then formation of a stable shock structure is similar to the numerical results of the Korteweg-de Vries-Burgers equation. The measured Mach number of the observed shock wave agrees with the theoretical results. Reduction of shock amplitude at large distances is also observed due to the dust neutral collision and viscosity effects. The dispersion relation and the spatial damping of a linear dust acoustic wave are also measured and compared with the relevant theory.

  5. On the existence of conservation law multiplier for partial differential equations

    Science.gov (United States)

    Zhang, Zhi-Yong

    2015-02-01

    In this paper, we use the property of nonlinear self-adjointness with differential substitution to study the existence of conservation law multiplier for partial differential equations (PDEs). Firstly, we give a sufficient and necessary condition for the existence of the multipliers involving only independent and dependent variables, which is the nonlinear self-adjointness of the studying PDEs. Secondly, a necessary condition for the existence of the multipliers involving derivatives is given for the general evolution PDEs, which is the nonlinear self-adjointness with differential substitution. Finally, applications of multiplier and nonlinear self-adjointness with differential substitution methods to nonlinear telegraph equations and a class of Korteweg-de Vries (KdV) type equations are performed and different types of conservation laws are constructed.

  6. Electrostatic solitary waves in pair-ion plasmas with trapped electrons

    Energy Technology Data Exchange (ETDEWEB)

    Mushtaq, A. [Department of Physics, Abdul Wali Khan University Mardan, Mardan (Pakistan); Ikram, M., E-mail: mikphysics@gmail.com [Department of Physics, Hazara University, Mansehra (Pakistan); Clark, R.E.H. [Departments of Physics and Astronomy, University of Texas at San Antonio, San Antonio (United States)

    2014-07-01

    Electrostatic solitons in an unmagnetized pair-ion plasma comprising adiabatic fluid positive and negative ions and non-isothermal electrons are investigated using both arbitrary and small amplitude techniques. An energy integral equation involving the Sagdeev potential is derived, and the basic properties of large amplitude solitary structures are investigated. Various features of solitons differ in different existence domains. The effects of ion adiabaticity, particle concentration, and resonant electrons on the profiles of Sagdeev potential and corresponding solitary waves are investigated. The generalized Korteweg-de Vries equation with mixed-nonlinearity is derived by expanding the Sagdeev potential. Asymptotic solutions for different orders of nonlinearity are discussed for solitary waves. The present work is applicable to understanding the wave phenomena and associated nonlinear electrostatic perturbations in pair/bi-ion plasmas which may occur in space and laboratory plasmas. (author)

  7. Ion acoustic solitary waves in magneto-rotating plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Mushtaq, A, E-mail: msherpao@gmail.co [School of Physics, University of Sydney, New South Wales 2006 (Australia); Theoretical Plasma Physics Division, PINSTECH, Nilore, Islamabad (Pakistan)

    2010-08-06

    Propagation of an ion acoustic wave (IAW) in a magnetized electron-ion plasma, which is rotating around an axis at an angle {theta} with the direction of magnetic field, is studied by incorporating the effects of trapped and untrapped electron distributions. Employing the perturbation scheme, Korteweg-deVries and Schamel's modified KdV equations are derived for the small angle {theta} which may support the nonlinear IAW on a slow time scale of ion motion. The amplitude and width of the solitary wave in both cases (trapped and untrapped electrons) have been discussed with the effects of oblique rotation and external magnetic field. It is shown that the nonlinear effects considerably influence the propagation of waves in rotating plasmas.

  8. Effects of plasma particle trapping on dust-acoustic solitary waves in an opposite polarity dust-plasma medium

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, Zulfiqar [Institute of Physics and Electronics, University of Peshawar, 25000 Peshawar (Pakistan); Mushtaq, A. [Department of Physics, Abdul Wali Khan University, Mardan 23200 (Pakistan); National Center for Physics, Shahdrah Valley Road, Islamabad 44000 (Pakistan); Mamun, A. A. [Department of Physics, Jahangirnagar University Savar, Dhaka 1342 (Bangladesh)

    2013-03-15

    Dust acoustic solitary waves in a dusty plasma containing dust of opposite polarity (adiabatic positive and negative dust), non-isothermal electrons and ions (following vortex like distribution) are theoretically investigated by employing pseudo-potential approach, which is valid for arbitrary amplitude structures. The propagation of small but finite amplitude solitary structures is also examined by using the reductive perturbation method. The basic properties of large (small) amplitude solitary structures are investigated by analyzing the energy integral (modified Korteweg-de Vries equation). It is shown that the effects of dust polarity, trapping of plasma particles (electrons and ions), and temperatures of dust fluids significantly modify the basic features of the dust-acoustic solitary structures that are found to exist in such an opposite polarity dust-plasma medium. The relevance of the work in opposite polarity dust-plasma, which may occur in cometary tails, upper mesosphere, Jupiter's magnetosphere, is briefly discussed.

  9. Linear and nonlinear studies of two-stream instabilities in electron-positron-ion plasmas with quantum corrections

    Energy Technology Data Exchange (ETDEWEB)

    Mushtaq, A; Khan, R [Theoretical Plasma Physics Division, PINSTECH, PO Nilore, Islamabad (Pakistan)], E-mail: mna99_pk@yahoo.com

    2008-07-15

    In this paper two-stream instabilities in electron-positron-ion plasmas with quantum corrections are studied in both the linear and nonlinear regimes. The relative motion of ions with respect to electron-positron plasma and of positrons with respect to electron-ion plasma can give rise to such instabilities. Analytically and numerically the growth rates are calculated; the growth rates mainly depend on the quantum corrections and percentage concentration of different species. In the nonlinear studies, by employing the reductive perturbation technique, the Korteweg-de Vries (KdV) equation is derived; the KdV equation admits the solitary wave solution. The effect of streaming in the presence of quantum corrections on the amplitude and width of electrostatic soliton is studied. The conditions for hump-like and dip-like solitary structures are discussed.

  10. Low-frequency shock waves in a magnetized superthermal dusty plasma

    Science.gov (United States)

    Chahal, B. S.; Ghai, Yashika; Saini, N. S.

    2017-09-01

    The characteristics of low-frequency shocks in a magnetized dusty plasma comprising of negatively charged dust fluid, kappa-distributed electrons and ions have been investigated. Using the reductive perturbation method, the nonlinear Korteweg de-Vries-Burgers (KdV-B) equation which governs the dynamics of the dust acoustic (DA) shock waves is derived. The characteristics of shock structures are studied under the influence of various plasma parameters, viz. superthermality of ions, magnetic field, electron-to-dust-density ratio, kinematic viscosity, ion-to-electron-temperature ratio and obliqueness. The combined effects of these physical parameters significantly influence the characteristics of DA shock structures. It is observed that only negative potential shocks exist in a plasma environment comprising of dust fluid and superthermal electrons and ions such as that of Saturn's magnetosphere.

  11. Effect of current vehicle’s interruption on traffic stability in cooperative car-following theory

    Science.gov (United States)

    Zhang, Geng; Liu, Hui

    2017-12-01

    To reveal the impact of the current vehicle’s interruption information on traffic flow, a new car-following model with consideration of the current vehicle’s interruption is proposed and the influence of the current vehicle’s interruption on traffic stability is investigated through theoretical analysis and numerical simulation. By linear analysis, the linear stability condition of the new model is obtained and the negative influence of the current vehicle’s interruption on traffic stability is shown in the headway-sensitivity space. Through nonlinear analysis, the modified Korteweg-de Vries (mKdV) equation of the new model near the critical point is derived and it can be used to describe the propagating behavior of the traffic density wave. Finally, numerical simulation confirms the analytical results, which shows that the current vehicle’s interruption information can destabilize traffic flow and should be considered in real traffic.

  12. On the method of strained parameters for a KdV type of equation with exact dispersion property

    CERN Document Server

    Karjanto, N

    2016-01-01

    This paper provides an alternative methodology for analysis of three-wave interactions under the exact dispersion relation associated with gravity waves in fluid of intermediate depth. A Korteweg-de Vries type of equation with exact dispersion property is adopted as the governing equation for unidirectional wave packet evolution. Following the idea from Zakharov's seminal paper (Zakharov, V. E. (1968) Stability of periodic waves of finite amplitude on the surface of a deep fluid. \\textit{Journal of Applied Mechanics and Technical Physics}, {\\bf 9}, 190--194), the equation is transformed from the spatial--temporal domain to the wavenumber--temporal domain. The solution of the transformed equation is sought using the perturbation theory, for which the ansatz is expressed in the form of a regular expansion in the increasing order of a small parameter. After implementing the na\\"{i}ve perturbation method, due to nonlinear mode generation and particular combinations of wavenumbers, the third-order solution contain...

  13. Extended Galilean transformations for high-order systems in two integrable hierarchies

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Dajun; Chen Dengyuan; Hu Liufeng, E-mail: djzhang@staff.shu.edu.cn [Department of Mathematics, Shanghai University, Shanghai 200444 (China)

    2011-04-15

    For some integrable hierarchies, there is no Galilean transformation that keeps a high-order equation in these hierarchies invariant, although the first one or two lower-order members admit Galilean invariance. However, the case might be changed if we redefine a high-order system. The redefined system consists of the considered high-order equation itself and all the lower-order members in their hierarchy, and each member of the hierarchy is numbered by introducing temporal coordinates (t{sub 0}, t{sub 1}, t{sub 2}, ...) to replace the uniform t. For such a redefined high-order system, one may construct an extended Galilean transformation that keeps the system invariant. Two examples, the high-order Burgers system and the Korteweg-de Vries system, are employed for demonstrating our point.

  14. Non linear analysis of obliquely propagating spin electron acoustic wave in a partially spin polarized degenerate plasma

    Science.gov (United States)

    Iqbal, Z.; Murtaza, G.

    2018-01-01

    By employing the separated spin evolution quantum hydrodynamic model, non-linear evolution of obliquely propagating spin electron acoustic wave (SEAW) is presented. The solitary structures of SEAW is investigated through the Korteweg-de Vries (KdV) equation derived using reductive perturbation method. From the first order perturbations we derive the dispersion relation of SEAW and find that both the spin polarization and the propagation angle reduce the phase velocity while the electron streaming enhances it. Using small amplitude approximation, the solitary structure of SEAW is analyzed and the effects of spin polarization, propagation angle and electron streaming on the SEA soliton are studied. Our numerical results demonstrate that the spin polarization and the propagation angle play a balancing act on the soliton structures. The possible applications of our investigation to the astrophysical environments like white dwarfs is also discussed.

  15. Effects of two-temperature ions on head-on collision and phase shifts of dust acoustic single- and multi-solitons in dusty plasma

    Science.gov (United States)

    Alam, M. S.; Hafez, M. G.; Talukder, M. R.; Hossain Ali, M.

    2017-10-01

    Propagation characteristics and interaction phenomena among the dust acoustic (DA) solitons in unmagnetized dusty plasmas are studied. The plasma is composed of negatively charged mobile dust, Boltzmann distributed electrons, and nonthermally distributed cold and hot ions. The extended Poincaré-Lighthill-Kuo method is employed to derive the two-sided Korteweg-de Vries (KdV) equations. The solutions of the KdV equations are constructed using the Hirota bilinear method both for single- and multi-solitons. The phase shifts are determined for the interactions among the two-, four-, and six-DA solitons. The effects of plasma parameters on the head-on collisions of the DA single- and multi-solitons and their corresponding phase shifts are investigated.

  16. Prevision of vehicle headway effect on urban traffic with a new car-following model

    Science.gov (United States)

    Peng, Guanghan; Lu, Weizhen; He, Hongdi; Gu, Zhenghua

    2017-04-01

    In this study, a new car-following model is established aiming to predict the variation of vehicle headways on urban road. The linear stability condition is derived corresponding to the prevision of headway in moving. The modified Korteweg-de Vries (mKdV) equation is deduced through the nonlinear analysis. The kink-antikink soliton solution of the mKdV equation can interpret the urban traffic jams near the critical point under the prevision of vehicle headway. Moreover, it is clear that the prevision of headway effect did improve the stability of urban traffic flow since the traffic jams are alleviated efficiently by taking into account the prevision of headway term in numerical simulations, which are consistent with the theoretical analysis.

  17. Fast magnetohydrodynamic cnoidal waves and solitons in electron-positron plasma

    Science.gov (United States)

    Ur-Rehman, Hafeez; Mahmood, S.; Kaladze, T.; Hussain, S.

    2018-01-01

    Linear and nonlinear propagation of fast magnetohydrodynamic waves (or magnetoacoustic waves) are studied in homogeneous, magnetized and warm collisionless electron-positron (e-p) plasma by using two fluid magnetohydrodynamic model. In the linear limit, the wave dispersion relation is obtained and wave dispersion effect which appears through inertial length in e-p plasma system is also discussed. Using reductive perturbation method, the Korteweg-de Vries (KdV) equation for small but finite wave amplitude of magnetoacoustic waves is derived with appropriate boundary conditions. The cnoidal wave and soliton solutions are obtained using well known Sagdeev potential approach for magnetoacoustic waves in e-p plasmas propagating in the direction perpendicular to the external magnetic field. The phase portrait analysis and numerical illustration of magnetoacoustic cnoidal waves and solitons is also presented by using the parameters such as magnetic field intensity, plasma density and temperature of electron and positron fluids for astrophysical plasma situations exist in the literature.

  18. Loss-less propagation, elastic and inelastic interaction of electromagnetic soliton in an anisotropic ferromagnetic nanowire

    Science.gov (United States)

    Senthil Kumar, V.; Kavitha, L.; Boopathy, C.; Gopi, D.

    2017-10-01

    Nonlinear interaction of electromagnetic solitons leads to a plethora of interesting physical phenomena in the diverse area of science that include magneto-optics based data storage industry. We investigate the nonlinear magnetization dynamics of a one-dimensional anisotropic ferromagnetic nanowire. The famous Landau-Lifshitz-Gilbert equation (LLG) describes the magnetization dynamics of the ferromagnetic nanowire and the Maxwell's equations govern the propagation dynamics of electromagnetic wave passing through the axis of the nanowire. We perform a uniform expansion of magnetization and magnetic field along the direction of propagation of electromagnetic wave in the framework of reductive perturbation method. The excitation of magnetization of the nanowire is restricted to the normal plane at the lowest order of perturbation and goes out of plane for higher orders. The dynamics of the ferromagnetic nanowire is governed by the modified Korteweg-de Vries (mKdV) equation and the perturbed modified Korteweg-de Vries (pmKdV) equation for the lower and higher values of damping respectively. We invoke the Hirota bilinearization procedure to mKdV and pmKdV equation to construct the multi-soliton solutions, and explicitly analyze the nature of collision phenomena of the co-propagating EM solitons for the above mentioned lower and higher values of Gilbert-damping due to the precessional motion of the ferromagnetic spin. The EM solitons appearing in the higher damping regime exhibit elastic collision thus yielding the fascinating state restoration property, whereas those of lower damping regime exhibit inelastic collision yielding the solitons of suppressed intensity profiles. The propagation of EM soliton in the nanoscale magnetic wire has potential technological applications in optimizing the magnetic storage devices and magneto-electronics.

  19. Oblique Interaction of Dust-ion Acoustic Solitons with Superthermal Electrons in a Magnetized Plasma

    Science.gov (United States)

    Parveen, Shahida; Mahmood, Shahzad; Adnan, Muhammad; Qamar, Anisa

    2018-01-01

    The oblique interaction between two dust-ion acoustic (DIA) solitons travelling in the opposite direction, in a collisionless magnetized plasma composed of dynamic ions, static dust (positive/negative) charged particles and interialess kappa distributed electrons is investigated. By employing extended Poincaré-Lighthill-Kuo (PLK) method, Korteweg-de Vries (KdV) equations are derived for the right and left moving low amplitude DIA solitons. Their trajectories and corresponding phase shifts before and after their interaction are also obtained. It is found that in negatively charged dusty plasma above the critical dust charged to ion density ratio the positive polarity pulse is formed, while below the critical dust charged density ratio the negative polarity pulse of DIA soliton exist. However it is found that only positive polarity pulse of DIA solitons exist for the positively charged dust particles case in a magnetized nonthermal plasma. The nonlinearity coefficient in the KdV equation vanishes for the negatively charged dusty plasma case for a particular set of parameters. Therefore, at critical plasma density composition for negatively charged dust particles case, the modified Korteweg-de Vries (mKdV) equations having cubic nonlinearity coefficient of the DIA solitons, and their corresponding phase shifts are derived for the left and right moving solitons. The effects of the system parameters including the obliqueness of solitons propagation with respect to magnetic field direction, superthermality of electrons and concentration of positively/negatively static dust charged particles on the phase shifts of the colliding solitons are also discussed and presented numerically. The results are applicable to space magnetized dusty plasma regimes.

  20. Solitary waves in fluids

    CERN Document Server

    Grimshaw, RHJ

    2007-01-01

    After the initial observation by John Scott Russell of a solitary wave in a canal, his insightful laboratory experiments and the subsequent theoretical work of Boussinesq, Rayleigh and Korteweg and de Vries, interest in solitary waves in fluids lapsed until the mid 1960's with the seminal paper of Zabusky and Kruskal describing the discovery of the soliton. This was followed by the rapid development of the theory of solitons and integrable systems. At the same time came the realization that solitary waves occur naturally in many physical systems, and play a fundamental role in many circumstances. The aim of this text is to describe the role that soliton theory plays in fluids in several contexts. After an historical introduction, the book is divided five chapters covering the basic theory of the Korteweg-de Vries equation, and the subsequent application to free-surface solitary waves in water to internal solitary waves in the coastal ocean and the atmospheric boundary layer, solitary waves in rotating flows, ...

  1. Surgical Challenges in Lymphatic Filariasis | de Vries | African ...

    African Journals Online (AJOL)

    African Journal of Urology. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 10, No 3 (2004) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register · Download this PDF file. The PDF file you selected should load ...

  2. Genetics Home Reference: Koolen-de Vries syndrome

    Science.gov (United States)

    ... affected individuals are missing a small amount of genetic material, including the KANSL1 gene, from one copy of ... no health problems related to the inversion. However, genetic material can be lost or duplicated when the inversion ...

  3. Nonlinear structures for extended Korteweg–de Vries equation in ...

    Indian Academy of Sciences (India)

    Department of Mathematics, Faculty of Science, Fayoum University, Al Fayoum, Egypt; Leeth University College, Umm Al-Qura University, Mecca, Saudi Arabia; Department of Mathematics, Faculty of Applied Sciences, Umm Al-Qura University, Mecca, Saudi Arabia; Department of Physics, Faculty of Science, Port Said ...

  4. Compactons in PT-symmetric generalized Korteweg–de Vries ...

    Indian Academy of Sciences (India)

    Department of Physics, Washington University, St. Louis, MO 63130, USA; National Science Foundation, Division of Physics, Arlington, VA 22230, USA and Santa Fe Institute, Santa Fe, NM 87501, USA; Theoretical Division and Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, NM 87545, USA ...

  5. Nonlinear structures for extended Korteweg–de Vries equation in ...

    Indian Academy of Sciences (India)

    tation blow-up indicates that an instability in the system may occur due to the effect of nonlinearity. In simple terms, the balance between dispersion and nonlinearity may be dis- turbed by variations of plasma quantities (e.g., temperature, pressure, density, etc.). This might locally destroy the localized excitation stability ...

  6. Nonlinear waves in viscoelastic magnetized complex astroplasmas with polarized dust-charge variations

    Science.gov (United States)

    Das, Papari; Karmakar, Pralay Kumar

    2018-01-01

    A nonextensive nonthermal magnetized viscoelastic astrofluid, compositionally containing nonthermal electrons and ions together with massive polarized dust micro-spherical grains of variable electric charge, is allowed to endure weakly nonlinear perturbation around its equilibrium. The nonextensivity originating from the large-scale non-local effects is included via the Tsallis thermo-statistical distribution laws describing the lighter species. Assuming the equilibrium as a homogeneous hydrostatic one, the dust polarization effects are incorporated via the conventional homogeneous polarization force law. The perturbed fluid model evolves as a unique conjugate pair of coupled extended Korteweg-de Vries (e-KdV) equations. A constructed numerical tapestry shows the collective excitations of a new pair of distinct classes of nonlinear mode structures in new parametric space. The first family indicates periodic electrostatic compressive eigenmodes in the form of soliton-chains. Likewise, the second one reveals gravitational rarefactive solitary patterns. Their microphysical multi-parametric dependencies of the eigen-patterns are illustratively analyzed and bolstered. The paper ends up with some promising implications and applications in the astro-cosmo-plasmic context of wave-induced accretive triggering processes responsible for gravitationally bounded (gravito-condensed) astro-structure formation, such as stellesimals, planetsimals, etc.

  7. Data-driven discovery of partial differential equations.

    Science.gov (United States)

    Rudy, Samuel H; Brunton, Steven L; Proctor, Joshua L; Kutz, J Nathan

    2017-04-01

    We propose a sparse regression method capable of discovering the governing partial differential equation(s) of a given system by time series measurements in the spatial domain. The regression framework relies on sparsity-promoting techniques to select the nonlinear and partial derivative terms of the governing equations that most accurately represent the data, bypassing a combinatorially large search through all possible candidate models. The method balances model complexity and regression accuracy by selecting a parsimonious model via Pareto analysis. Time series measurements can be made in an Eulerian framework, where the sensors are fixed spatially, or in a Lagrangian framework, where the sensors move with the dynamics. The method is computationally efficient, robust, and demonstrated to work on a variety of canonical problems spanning a number of scientific domains including Navier-Stokes, the quantum harmonic oscillator, and the diffusion equation. Moreover, the method is capable of disambiguating between potentially nonunique dynamical terms by using multiple time series taken with different initial data. Thus, for a traveling wave, the method can distinguish between a linear wave equation and the Korteweg-de Vries equation, for instance. The method provides a promising new technique for discovering governing equations and physical laws in parameterized spatiotemporal systems, where first-principles derivations are intractable.

  8. Ion-acoustic dressed solitary structures in two component plasma with Tsallis-nonthermal velocity distribution of electrons

    Science.gov (United States)

    Bala, Parveen; Gill, Tarsem Singh; Bains, Amandeep Singh; Kaur, Harvinder

    2017-12-01

    The present investigation deals with the study of small amplitude nonlinear ion-acoustic dressed solitary structures in two component plasma model consisting of cold positive ions and electrons. The electrons are assumed as featuring hybrid q-nonextensive nonthermal distribution also known as Cairns-Tsallis velocity distribution. In the lowest order of potential, the basic set of fluid equations is reduced to the well known Korteweg-de Vries ( KdV) equation. By including the contribution of higher order potential, an inhomogeneous KdV-type nonliner equation results that contains fifth order dispersion. The numerical values of the parameters like nonthermal (α) and nonextensive ( q) are according to the range suggested by Williams et al. (Phys Rev E 88:023103, 2013). The finite value of nonthermal parameter results into the formation of rarefactive type solitary structures. A comparison of amplitudes of higher order correction, dressed and KdV solitons has been presented pictorially. The combined effect of nonextensive parameter q and nontermal parameter on the soliton dynamics has also been studied and the results are shown in the form of two and three dimensional profiles.

  9. Resolution of a shock in hyperbolic systems modified by weak dispersion

    Science.gov (United States)

    El, G. A.

    2005-09-01

    We present a way to deal with dispersion-dominated "shock-type" transition in the absence of completely integrable structure for the systems that one may characterize as strictly hyperbolic regularized by a small amount of dispersion. The analysis is performed by assuming that the dispersive shock transition between two different constant states can be modeled by an expansion fan solution of the associated modulation (Whitham) system for the short-wavelength nonlinear oscillations in the transition region (the so-called Gurevich-Pitaevskii problem). We consider both single-wave and bidirectional systems. The main mathematical assumption is that of hyperbolicity of the Whitham system for the solutions of our interest. By using general properties of the Whitham averaging for a certain class of nonlinear dispersive systems and specific features of the Cauchy data prescription on characteristics we derive a set of transition conditions for the dispersive shock, actually bypassing full integration of the modulation equations. Along with the Korteweg-de Vries (KdV) and modified KdV (mKdV) equations as model examples, we consider a nonintegrable system describing fully nonlinear ion-acoustic waves in collisionless plasma. In all cases our transition conditions are in complete agreement with previous analytical and numerical results.

  10. Continuous dynamic assimilation of the inner region data in hydrodynamics modelling: optimization approach

    Directory of Open Access Journals (Sweden)

    F. I. Pisnitchenko

    2008-11-01

    Full Text Available In meteorological and oceanological studies the classical approach for finding the numerical solution of the regional model consists in formulating and solving a Cauchy-Dirichlet problem. The boundary conditions are obtained by linear interpolation of coarse-grid data provided by a global model. Errors in boundary conditions due to interpolation may cause large deviations from the correct regional solution. The methods developed to reduce these errors deal with continuous dynamic assimilation of known global data available inside the regional domain. One of the approaches of this assimilation procedure performs a nudging of large-scale components of regional model solution to large-scale global data components by introducing relaxation forcing terms into the regional model equations. As a result, the obtained solution is not a valid numerical solution to the original regional model. Another approach is the use a four-dimensional variational data assimilation procedure which is free from the above-mentioned shortcoming. In this work we formulate the joint problem of finding the regional model solution and data assimilation as a PDE-constrained optimization problem. Three simple model examples (ODE Burgers equation, Rossby-Oboukhov equation, Korteweg-de Vries equation are considered in this paper. Numerical experiments indicate that the optimization approach can significantly improve the precision of the regional solution.

  11. Remark on the phase shift in the Kuzmak-Whitham ansatz

    Science.gov (United States)

    Dobrokhotov, S. Yu.; Minenkov, D. S.

    2011-03-01

    We consider one-phase ( formal) asymptotic solutions in the Kuzmak-Whitham form for the nonlinear Klein-Gordon equation and for the Korteweg-de Vries equation. In this case, the leading asymptotic expansion term has the form X( S( x, t)/ h+Φ( x, t), I( x, t), x, t) + O( h), where h ≪ 1 is a small parameter and the phase S}( x, t) and slowly changing parameters I( x, t) are to be found from the system of "averaged" Whitham equations. We obtain the equations for the phase shift Φ( x, t) by studying the second-order correction to the leading term. The corresponding procedure for finding the phase shift is then nonuniform with respect to the transition to a linear (and weakly nonlinear) case. Our observation, which essentially follows from papers by Haberman and collaborators, is that if we incorporate the phase shift Φ into the phase and adjust the parameter Ĩ by setting tilde S = S + hΦ+ O( h 2), Ĩ = I + hI 1 + O( h 2), then the functions tilde S ( x, t, h) and Ĩ( x, t, h) become solutions of the Cauchy problem for the same Whitham system but with modified initial conditions. These functions completely determine the leading asymptotic term, which is X( tilde S ( x, t, h)/ h, Ĩ( x, t, h), x, t) + O( h).

  12. Conservative regularization of ideal hydrodynamics and magnetohydrodynamics

    Science.gov (United States)

    Thyagaraja, A.

    2010-03-01

    Inviscid, incompressible hydrodynamics and incompressible ideal magnetohydrodynamics (MHD) share many properties such as time-reversal invariance of equations, conservation laws, and certain topological features. In three dimensions, these systems may lead to singular solutions (involving vortex and current sheets). While dissipative (viscoresistive) effects can regularize the equations leading to bounded solutions to the initial-boundary value (Cauchy) problem which presumably exist uniquely, the time-reversal symmetry and associated conservation properties are certainly destroyed. The present work is analogous to (and suggested by) the Korteweg-de Vries regularization of the one-dimensional, nonlinear kinematic wave equation. Thus the regularizations applied to the original equations of hydrodynamics and ideal MHD retain conservation properties and the symmetries of the original equations. Integral invariants which generalize those known for the original systems are shown to imply bounded enstrophy. The regularization developed can also be applied to the corresponding dissipative models (such as the Navier-Stokes equations and the viscoresistive MHD equations) and may imply interesting regularity properties for the solutions of the latter as well. The models developed thus have intrinsic mathematical interest as well as possible applications to large-scale numerical simulations in systems where dissipative effects are extremely small or even absent.

  13. Continuous dynamic assimilation of the inner region data in hydrodynamics modelling: optimization approach

    Science.gov (United States)

    Pisnitchenko, F. I.; Pisnichenko, I. A.; Martínez, J. M.; Santos, S. A.

    2008-11-01

    In meteorological and oceanological studies the classical approach for finding the numerical solution of the regional model consists in formulating and solving a Cauchy-Dirichlet problem. The boundary conditions are obtained by linear interpolation of coarse-grid data provided by a global model. Errors in boundary conditions due to interpolation may cause large deviations from the correct regional solution. The methods developed to reduce these errors deal with continuous dynamic assimilation of known global data available inside the regional domain. One of the approaches of this assimilation procedure performs a nudging of large-scale components of regional model solution to large-scale global data components by introducing relaxation forcing terms into the regional model equations. As a result, the obtained solution is not a valid numerical solution to the original regional model. Another approach is the use a four-dimensional variational data assimilation procedure which is free from the above-mentioned shortcoming. In this work we formulate the joint problem of finding the regional model solution and data assimilation as a PDE-constrained optimization problem. Three simple model examples (ODE Burgers equation, Rossby-Oboukhov equation, Korteweg-de Vries equation) are considered in this paper. Numerical experiments indicate that the optimization approach can significantly improve the precision of the regional solution.

  14. The Cauchy Problem and Stability of Solitary-Wave Solutions for RLW-KP-Type Equations

    Science.gov (United States)

    Bona, Jerry L.; Liu, Yue; Tom, Michael M.

    The Kadomtsev-Petviashvilli (KP) equation,( ut+ ux+ uux+ uxxx) x+ ɛuyy=0, (*) arises in various contexts where nonlinear dispersive waves propagate principally along the x-axis, but with weak dispersive effects being felt in the direction parallel to the y-axis perpendicular to the main direction of propagation. We propose and analyze here a class of evolution equations of the form ( ut+ ux+ upux+ Lut) x+ ɛuyy=0, (**) which provides an alternative to Eq.(*) in the same way the regularized long-wave equation is related to the classical Korteweg-de Vries (KdV) equation. The operator L is a pseudo-differential operator in the x-variable, p⩾1 is an integer and ɛ=±1. After discussing the underlying motivation for the class (**), a local well-posedness theory for the initial-value problem is developed. With assumptions on L and p that include conditions appertaining to models of interesting physical phenomenon, the solutions defined locally in time t are shown to be smoothly extendable to the entire time-axis. In the particularly interesting case where L=-∂ x2 and ɛ=-1, (*) possesses travelling-wave solutions u( x, y, t)=π c( x- ct, y) provided c>1 and 01 and for {4}/{3}(4 p)/(4+ p). The paper concludes with commentary on extensions of the present theory to more than two space dimensions.

  15. Some exact solutions to the Lighthill-Whitham-Richards-Payne traffic flow equations

    Science.gov (United States)

    Rowlands, G.; Infeld, E.; Skorupski, A. A.

    2013-09-01

    We find a class of exact solutions to the Lighthill-Whitham-Richards-Payne (LWRP) traffic flow equations. Using two consecutive Lagrangian transformations, a linearization is achieved. Next, depending on the initial density, we either apply (again two) Lambert functions and obtain exact formulae for the dependence of the car density and velocity on x, t, or else, failing that, the same result in a parametric representation. The calculation always involves two possible factorizations of a consistency condition. Both must be considered. In physical terms, the lineup usually separates into two offshoots at different velocities. Each velocity soon becomes uniform. This outcome in many ways resembles the two soliton solution to the Korteweg-de Vries equation. We check general conservation requirements. Although traffic flow research has developed tremendously since LWRP, this calculation, being exact, may open the door to solving similar problems, such as gas dynamics or water flow in rivers. With this possibility in mind, we outline the procedure in some detail at the end.

  16. Harmonic generation in the generalized Sagdeev pseudopotential

    Science.gov (United States)

    Akbari-Moghanjoughi, M.

    2017-09-01

    In this paper, we study the nonlinear harmonic generation effect in different oscillator models. For weakly nonlinear systems, we use the generalized forced Korteweg de Vries Burgers (KdVB) and modified KdVB (mKdVB) models in order to classify three fundamentally different harmonic structures in a nonlinear dynamical system. The first is called the internal harmonic structure which exists due to the self oscillation of the system in the absence of dissipation effect and is shown to follow either relations of nf or (2n - 1)f depending on the symmetry of oscillator potential in which n is an integer number and f is the fundamental frequency which is exactly obtained for the Helmholtz oscillator. The second structure is the resonant harmonics which appears in the presence of damping and follows the harmonic structure nf0 in which f0 is the linear resonance frequency. Finally, the last harmonic structure appears in the presence of dissipation and external periodic forcing effects which we call the external harmonic pattern. It is shown that the external harmonic pattern, in which f1 is the driving frequency, always follows the nf1 rule regardless of the potential symmetry. We then extend our analysis to study the harmonic generation in the fully nonlinear generalized Sagdeev potential for real plasmas with isothermal and adiabatic ion fluids and investigate the effects of different plasma parameters such as the fractional ion temperature and normalized ion acoustic speed on all three kinds of harmonic generation.

  17. Magnetosonic solitons in semiconductor plasmas in the presence of quantum tunneling and exchange correlation effects

    Science.gov (United States)

    Hussain, S.; Mahmood, S.

    2018-01-01

    Low frequency magnetosonic wave excitations are investigated in semiconductor hole-electron plasmas. The quantum mechanical effects such as Fermi pressure, quantum tunneling, and exchange-correlation of holes and electrons in the presence of the magnetic field are considered. The two fluid quantum magnetohydrodynamic model is used to study magnetosonic wave dynamics, while electric and magnetic fields are coupled via Maxwell equations. The dispersion relation of the magnetosonic wave in electron-hole semiconductor plasma propagating in the perpendicular direction of the magnetic field is obtained, and its dispersion effects are discussed. The Korteweg-de Vries equation (KdV) for magnetosonic solitons is derived by employing the reductive perturbation method. For numerical analysis, the plasma parameters are taken from the semiconductors such as GaAs, GaSb, GaN, and InP already existing in the literature. It is found that the phase velocity of the magnetosonic wave is increased with the inclusion of exchange-correlation force in the model. The soliton dip structures of the magnetosonic wave in GaN semiconductor plasma are obtained, which satisfy the quantum plasma conditions for electron and hole fluids. The magnetosonic soliton dip structures move with speed less than the magnetosonic wave phase speed in the lab frame. The effects of exchange-correlation force in the model and variations of magnetic field intensity and electron/hole density on the magnetosonic wave dip structures are also investigated numerically for illustration.

  18. Roles of positively charged heavy ions and degenerate plasma pressure on cylindrical and spherical ion acoustic solitary waves

    Science.gov (United States)

    Hossen, M. R.; Nahar, L.; Sultana, S.; Mamun, A. A.

    2014-09-01

    The properties of heavy-ion-acoustic (HIA) solitary structures associated with the nonlinear propagation of cylindrical and spherical electrostatic perturbations in an unmagnetized, collisionless dense plasma system has been investigated theoretically. Our considered model contains degenerate electron and inertial light ion fluids, and positively charged static heavy ions, which is valid for both of the non-relativistic and ultra-relativistic limits. The Korteweg-de Vries (K-dV) and modified K-dV (mK-dV) equations have been derived by employing the reductive perturbation method, and numerically examined in order. It has been found that the effect of degenerate pressure and number density of electron and inertial light ion fluids, and positively charged static heavy ions significantly modify the basic features of HIA solitary waves. It is also noted that the inertial light ion fluid is the source of dispersion for HIA waves and is responsible for the formation of solitary waves. The basic features and the underlying physics of HIA solitary waves, which are relevant to some astrophysical compact objects, are briefly discussed.

  19. Nonlinear waves in bipolar complex viscous astroclouds

    Science.gov (United States)

    Karmakar, P. K.; Haloi, A.

    2017-05-01

    A theoretical evolutionary model to analyze the dynamics of strongly nonlinear waves in inhomogeneous complex astrophysical viscous clouds on the gravito-electrostatic scales of space and time is procedurally set up. It compositionally consists of warm lighter electrons and ions (Boltzmanian); and cold massive bi-polar dust grains (inertial fluids) alongside vigorous neutral dynamics in quasi-neutral hydrodynamic equilibrium. Application of the Sagdeev pseudo-potential method reduces the inter-coupled structure equations into a pair of intermixed forced Korteweg-de Vries-Burgers (f-KdVB) equations. The force-terms are self-consistently sourced by inhomogeneous gravito-electrostatic interplay. A numerical illustrative shape-analysis based on judicious astronomical parametric platform shows the electrostatic waves evolving as compressive dispersive shock-like eigen-modes. A unique transition from quasi-monotonic to non-monotonic oscillatory compressive shock-like patterns is found to exist. In contrast, the self-gravitational and effective perturbations grow purely as non-monotonic compressive oscillatory shock-like structures with no such transitory features. It is seen that the referral frame velocity acts as amplitude-reducing agent (stabilizing source) for the electrostatic fluctuations solely. A comparison in the prognostic light of various earlier satellite-based observations and in-situ measurements is presented. The paper ends up with synoptic highlights on the main implications and non-trivial applications in the interstellar space and cosmic plasma environments leading to bounded structure formation.

  20. A Novel Interpretation for Arterial Pulse Pressure Amplification in Health and Disease

    Directory of Open Access Journals (Sweden)

    Manuel R. Alfonso

    2018-01-01

    Full Text Available Arterial pressure waves have been described in one dimension using several approaches, such as lumped (Windkessel or distributed (using Navier-Stokes equations models. An alternative approach consists of modeling blood pressure waves using a Korteweg-de Vries (KdV equation and representing pressure waves as combinations of solitons. This model captures many key features of wave propagation in the systemic network and, in particular, pulse pressure amplification (PPA, which is a mechanical biomarker of cardiovascular risk. The main objective of this work is to compare the propagation dynamics described by a KdV equation in a human-like arterial tree using acquired pressure waves. Furthermore, we analyzed the ability of our model to reproduce induced elastic changes in PPA due to different pathological conditions. To this end, numerical simulations were performed using acquired central pressure signals from different subject groups (young, adults, and hypertensive as input and then comparing the output of the model with measured radial artery pressure waveforms. Pathological conditions were modeled as changes in arterial elasticity (E. Numerical results showed that the model was able to propagate acquired pressure waveforms and to reproduce PPA variations as a consequence of elastic changes. Calculated elasticity for each group was in accordance with the existing literature.

  1. Landau damping of Gardner solitons in a dusty bi-ion plasma

    CERN Document Server

    Misra, A P

    2015-01-01

    The effects of linear Landau damping on the nonlinear propagation of dust-acoustic solitary waves (DASWs) are studied in a collisionless unmagnetized dusty plasma with two species of positive ions. The extremely massive, micron-seized, cold and negatively charged dust particles are described by fluid equations, whereas the two species of positive ions, namely the cold (heavy) and hot (light) ions are described by the kinetic Vlasov equations. Following Ott and Sudan [Phys. Fluids {\\bf 12}, 2388 (1969)], and by considering lower and higher-order perturbations, the evolution of DASWs with Landau damping is shown to be governed by Korteweg-de Vries (KdV), modified KdV (mKdV) or Gardner (KdV-mKdV)-like equations. The properties of the phase velocity and the Landau damping rate of DASWs are studied for different values of the ratios of the temperatures $(\\sigma)$ and the number densities $(\\mu)$ of hot and cold ions as well the cold to hot ion mass ratio $m$. The distinctive features of the decay rates of the ampl...

  2. Atmospheric gravity waves in the Red Sea: a new hotspot

    KAUST Repository

    Magalhaes, J. M.

    2011-02-03

    The region of the Middle East around the Red Sea (between 32° E and 44° E longitude and 12° N and 28° N latitude) is a currently undocumented hotspot for atmospheric gravity waves (AGWs). Satellite imagery shows evidence that this region is prone to relatively high occurrence of AGWs compared to other areas in the world, and reveals the spatial characteristics of these waves. The favorable conditions for wave propagation in this region are illustrated with three typical cases of AGWs propagating in the lower troposphere over the sea. Using weakly nonlinear long wave theory and the observed characteristic wavelengths we obtain phase speeds which are consistent with those observed and typical for AGWs, with the Korteweg-de Vries theory performing slightly better than Benjamin-Davis-Acrivos-Ono theory as far as phase speeds are concerned. ERS-SAR and Envisat-ASAR satellite data analysis between 1993 and 2008 reveals signatures consistent with horizontally propagating large-scale internal waves. These signatures cover the entire Red Sea and are more frequently observed between April and September, although they also occur during the rest of the year. The region\\'s (seasonal) propagation conditions for AGWs, based upon average vertical atmospheric stratification profiles suggest that many of the signatures identified in the satellite images are atmospheric internal waves. © Author(s) 2011.

  3. Solitary wave evolution in a magnetized inhomogeneous plasma under the effect of ionization

    Science.gov (United States)

    Jyoti; Malik, Hitendra K.

    2011-10-01

    A modified form of Korteweg-deVries (KdV) equation appropriate to nonlinear ion acoustic solitary waves in an inhomogeneous plasma is derived in the presence of an external magnetic field and constant ionization in the plasma. This equation differs from usual version of the KdV equation because of the inclusion of two terms arising due to ionization and density gradient present in the plasma. In this plasma, only the compressive solitary waves are found to propagate corresponding to the fast and slow modes. The amplitude of the solitary wave increases with an enhancement in the ionization for the fast mode as well as for the slow mode. The effect of magnetic field is to enhance the width of the solitary structure. The amplitude is found to increase (decrease) with an enhancement in charge number of the ions for the fast (slow) mode. The tailing structure becomes more (less) prominent with the rise in ion drift velocity for the case of fast (slow) mode.

  4. Magnetosonic shock wave in collisional pair-ion plasma

    Energy Technology Data Exchange (ETDEWEB)

    Adak, Ashish, E-mail: ashish-adak@yahoo.com; Khan, Manoranjan, E-mail: mkhan.ju@gmail.com [Department of Instrumentation Science, Jadavpur University, Kolkata 700 032 (India); Sikdar, Arnab, E-mail: arnabs.ju@gmail.com [Department of Mathematics, Calcutta Institute of Engineering and Management, 24/1A Chandi Ghosh Road, Kolkata 700040 (India); Ghosh, Samiran, E-mail: sran-g@yahoo.com [Department of Applied Mathematics, University of Calcutta, 92, Acharya Prafulla Chandra Road, Kolkata 700 009 (India)

    2016-06-15

    Nonlinear propagation of magnetosonic shock wave has been studied in collisional magnetized pair-ion plasma. The masses of both ions are same but the temperatures are slightly different. Two fluid model has been taken to describe the model. Two different modes of the magnetosonic wave have been obtained. The dynamics of the nonlinear magnetosonic wave is governed by the Korteweg-de Vries Burgers' equation. It has been shown that the ion-ion collision is the source of dissipation that causes the Burgers' term which is responsible for the shock structures in equal mass pair-ion plasma. The numerical investigations reveal that the magnetosonic wave exhibits both oscillatory and monotonic shock structures depending on the strength of the dissipation. The nonlinear wave exhibited the oscillatory shock wave for strong magnetic field (weak dissipation) and monotonic shock wave for weak magnetic field (strong dissipation). The results have been discussed in the context of the fullerene pair-ion plasma experiments.

  5. Complex solitons with real energies

    Science.gov (United States)

    Cen, Julia; Fring, Andreas

    2016-09-01

    Using Hirota’s direct method and Bäcklund transformations we construct explicit complex one and two-soliton solutions to the complex Korteweg-de Vries (KdV) equation, the complex modified KdV (mKdV) equation and the complex sine-Gordon equation. The one-soliton solutions of trigonometric and elliptic type turn out to be { P }{ T }-symmetric when a constant of integration is chosen to be purely imaginary with one special choice corresponding to solutions recently found by Khare and Saxena. We show that alternatively complex { P }{ T }-symmetric solutions to the KdV equation may also be constructed alternatively from real solutions to the mKdV by means of Miura transformations. The multi-soliton solutions obtained from Hirota’s method break the { P }{ T }-symmetric, whereas those obtained from Bäcklund transformations are { P }{ T }-invariant under certain conditions. Despite the fact that some of the Hamiltonian densities are non-Hermitian, the total energy is found to be positive in all cases, that is irrespective of whether they are { P }{ T }-symmetric or not. The reason is that the symmetry can be restored by suitable shifts in space-time and the fact that any of our N-soliton solutions may be decomposed into N separate { P }{ T }-symmetrizable one-soliton solutions.

  6. Particle-in-cell simulation of large amplitude ion-acoustic solitons

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Sarveshwar, E-mail: sarvsarvesh@gmail.com; Sengupta, Sudip; Sen, Abhijit [Institute for Plasma Research, Bhat, Gandhinagar 382 428 (India)

    2015-02-15

    The propagation of large amplitude ion-acoustic solitons is studied in the laboratory frame (x, t) using a 1-D particle-in-cell code that evolves the ion dynamics by treating them as particles but assumes the electrons to follow the usual Boltzmann distribution. It is observed that for very low Mach numbers the simulation results closely match the Korteweg-de Vries soliton solutions, obtained in the wave frame, and which propagate without distortion. The collision of two such profiles is observed to exhibit the usual solitonic behaviour. As the Mach number is increased, the given profile initially evolves and then settles down to the exact solution of the full non-linear Poisson equation, which then subsequently propagates without distortion. The fractional change in amplitude is found to increase linearly with Mach number. It is further observed that initial profiles satisfying k{sup 2}λ{sub de}{sup 2}<1 break up into a series of solitons.

  7. Acoustic solitons: A robust tool to investigate the generation and detection of ultrafast acoustic waves

    Science.gov (United States)

    Péronne, Emmanuel; Chuecos, Nicolas; Thevenard, Laura; Perrin, Bernard

    2017-02-01

    Solitons are self-preserving traveling waves of great interest in nonlinear physics but hard to observe experimentally. In this report an experimental setup is designed to observe and characterize acoustic solitons in a GaAs(001) substrate. It is based on careful temperature control of the sample and an interferometric detection scheme. Ultrashort acoustic solitons, such as the one predicted by the Korteweg-de Vries equation, are observed and fully characterized. Their particlelike nature is clearly evidenced and their unique properties are thoroughly checked. The spatial averaging of the soliton wave front is shown to account for the differences between the theoretical and experimental soliton profile. It appears that ultrafast acoustic experiments provide a precise measurement of the soliton velocity. It allows for absolute calibration of the setup as well as the response function analysis of the detection layer. Moreover, the temporal distribution of the solitons is also analyzed with the help of the inverse scattering method. It shows how the initial acoustic pulse profile which gives birth to solitons after nonlinear propagation can be retrieved. Such investigations provide a new tool to probe transient properties of highly excited matter through the study of the emitted acoustic pulse after laser excitation.

  8. Coupled ion acoustic and drift waves in magnetized superthermal electron-positron-ion plasmas

    Science.gov (United States)

    Adnan, Muhammad; Mahmood, S.; Qamar, Anisa

    2014-09-01

    Linear and nonlinear coupled drift-ion acoustic waves are investigated in a nonuniform magnetoplasma having kappa distributed electrons and positrons. In the linear regime, the role of kappa distribution and positron content on the dispersion relation has been highlighted; it is found that strong superthermality (low value of κ) and addition of positrons lowers the phase velocity via decreasing the fundamental scalelengths of the plasmas. In the nonlinear regime, first, coherent nonlinear structure in the form of dipoles and monopoles are obtained and the boundary conditions (boundedness) in the context of superthermality and positron concentrations are discussed. Second, in case of scalar nonlinearity, a Korteweg-de Vries-type equation is obtained, which admit solitary wave solution. It is found that both compressive and rarefactive solitons are formed in the present model. The present work may be useful to understand the low frequency electrostatic modes in inhomogeneous electron positron ion plasmas, which exist in astrophysical plasma situations such as those found in the pulsar magnetosphere.

  9. Effect of ion beam on the characteristics of ion acoustic Gardner solitons and double layers in a multicomponent superthermal plasma

    Science.gov (United States)

    Kaur, Nimardeep; Singh, Kuldeep; Saini, N. S.

    2017-09-01

    The nonlinear propagation of ion acoustic solitary waves (IASWs) is investigated in an unmagnetized plasma composed of a positive warm ion fluid, two temperature electrons obeying kappa type distribution and penetrated by a positive ion beam. The reductive perturbation method is used to derive the nonlinear equations, namely, Korteweg-de Vries (KdV), modified KdV (mKdV), and Gardner equations. The characteristic features of both compressive and rarefactive nonlinear excitations from the solution of these equations are studied and compared in the context with the observation of the He+ beam in the polar cap region near solar maximum by the Dynamics Explorer 1 satellite. It is observed that the superthermality and density of cold electrons, number density, and temperature of the positive ion beam crucially modify the basic properties of compressive and rarefactive IASWs in the KdV and mKdV regimes. It is further analyzed that the amplitude and width of Gardner solitons are appreciably affected by different plasma parameters. The characteristics of double layers are also studied in detail below the critical density of cold electrons. The theoretical results may be useful for the observation of nonlinear excitations in laboratory and ion beam driven plasmas in the polar cap region near solar maximum and polar ionosphere as well in Saturn's magnetosphere, solar wind, pulsar magnetosphere, etc., where the population of two temperature superthermal electrons is present.

  10. Quaternionic soliton equations from Hamiltonian curve flows in HP{sup n}

    Energy Technology Data Exchange (ETDEWEB)

    Anco, Stephen C; Asadi, Esmaeel [Department of Mathematics, Brock University, St Catharines, ON (Canada)], E-mail: sanco@brocku.ca, E-mail: easadi@brocku.ca

    2009-12-04

    A bi-Hamiltonian hierarchy of quaternion soliton equations is derived from geometric non-stretching flows of curves in the quaternionic projective space HP{sup n}. The derivation adapts the method and results in recent work by one of us on the Hamiltonian structure of non-stretching curve flows in Riemannian symmetric spaces M = G/H by viewing HP{sup n} as a symmetric space in terms of compact real symplectic groups and quaternion unitary groups. As main results, scalar-vector (multi-component) versions of the sine-Gordon (SG) equation and the modified Korteweg-de Vries (mKdV) equation are obtained along with their bi-Hamiltonian integrability structure consisting of a shared hierarchy of quaternionic symmetries and conservation laws generated by a hereditary recursion operator. The corresponding geometric curve flows in HP{sup n} are shown to be described by a non-stretching wave map and a mKdV analog of a non-stretching Schroedinger map.

  11. Polynômes 3-Tangentiels Et Solutions t-Périodiques de KdV

    Science.gov (United States)

    Flédrich, Pierre

    2006-05-01

    Nous étudions, quel que soit le réseau Λ subset mathbb{C}, les courbes hyperelliptiques donnant lieu, via le dictionnaire de Krichever et la formule d’Its-Mateev, à des solutions méromorphes Λ-doublement périodiques en t de l’équation de Korteweg-de Vries. Ce sont des revêtements π _Γ {:} (Γ ,p)rightarrow (X,q) marqués finis particuliers de la courbe elliptique ( X, q)=( C /Λ,0) que nous nommons paires osculatrices hyperelliptiques. Nous sommes amenés à définir la classe des polynômes 3-tangentiels symétriques et à considérer une surface algébrique réglée S→ X et la surface S^{bot } obtenue par un éclatement en huit points de S. Nous associons alors aux polynômes 3-tangentiels symétriques des diviseurs sur S et S^{bot }. En étudiant ces diviseurs, nous démontrons que les paires osculatrices non-ramifiées au point marqué se factorisent via S^{bot }rightarrow Srightarrow X, et reconstruisons ensuite de telles paires sur S^{bot } sous certaines conditions numériques.

  12. Cylindrical freak waves in a non-Maxwellian dusty bulk-sheath plasma: An approximate solution for the cylindrical nonlinear Schrödinger equation

    Science.gov (United States)

    El-Tantawy, S. A.; Elgendy, A. T.; Ismail, S.

    2017-10-01

    The properties of cylindrical dust ion-acoustic freak waves (FWs) are investigated in an unmagnetized collisionless dusty plasma in the presence of the sheath bulk model, which contain stationary negatively charged dust grains, nonthermal electrons, and inertial warm ions. For this purpose, the reductive perturbation method is used to reduce the fluid equations to a cylindrical Gardner/extended Korteweg-de Vries (CEKdV) equation. After that a cylindrical nonlinear Schrödinger equation (CNLSE) is obtained from the cylindrical EKdV using the derivative expansion method. The variation of the structural properties of the planar (one-dimensional) FWs with relevant plasma parameters is examined, in particular focusing on the temperature ratio of the ions-to-electrons, the fraction of negative charge residing on the dust and the nonthermal parameter. Moreover, the nonlinear dynamic of the sheath is obtain which may explain the solution of the exact analytical freak wave of the CNLSE using a suitable transformation.

  13. Effects of ionization and ion loss on dust ion-acoustic solitary waves in a collisional dusty plasma with suprathermal electrons

    Energy Technology Data Exchange (ETDEWEB)

    Mayout, Saliha; Gougam, Leila Ait [Faculty of Physics, Theoretical Physics Laboratory, Plasma Physics Group, University of Bab-Ezzouar, USTHB, B.P. 32, El Alia, Algiers 16111 (Algeria); Tribeche, Mouloud, E-mail: mouloudtribeche@yahoo.fr, E-mail: mtribeche@usthb.dz [Faculty of Physics, Theoretical Physics Laboratory, Plasma Physics Group, University of Bab-Ezzouar, USTHB, B.P. 32, El Alia, Algiers 16111 (Algeria); Algerian Academy of Sciences and Technologies, Algiers (Algeria)

    2016-03-15

    The combined effects of ionization, ion loss, and electron suprathermality on dust ion-acoustic solitary waves in a collisional dusty plasma are examined. Carrying out a small but finite amplitude analysis, a damped Korteweg-de Vries (dK–dV) equation is derived. The damping term decreases with the increase of the spectral index and saturates for Maxwellian electrons. Choosing typical plasma parameters, the analytical approximate solution of the dK-dV equation is numerically analyzed. We first neglect the ionization and ion loss effects and account only for collisions to estimate the relative importance between these damping terms which can act concurrently. Interestingly, we found that as the suprathermal character of the electrons becomes important, the strength of the collisions related dissipation becomes more important and causes the dust ion-acoustic solitary wave amplitude to decay more rapidly. Moreover, the collisional damping may largely prevail over the ionization and ion loss related damping. The latter becomes more effective as the electrons evolve far away from their thermal equilibrium. Our results complement and provide new insights into previously published work on this problem.

  14. Dust-acoustic solitary waves and shocks in strongly coupled quantum plasmas

    CERN Document Server

    Wang, Y

    2014-01-01

    We investigate the propagation characteristics of electrostatic dust-acoustic (DA) solitary waves and shocks in a strongly coupled dusty plasma consisting of intertialess electrons and ions, and strongly coupled inertial charged dust particles. A generalized viscoelastic hydrodynamic model with the effects of electrostatic dust pressure associated with the strong coupling of dust particles, and a quantum hydrodynamic model with the effects of quantum forces associated with the Bohm potential and the exchange-correlation potential for electrons and ions are considered. Both the linear and weakly nonlinear theory of DA waves are studied by the derivation and analysis of dispersion relations as well as Korteweg-de Vries (KdV) and KdV-Burgers (KdVB)-like equations. It is shown that in the kinetic regime ($\\omega\\tau_m\\gg1$, where $\\omega$ is the wave frequency and $\\tau_m$ is the viscoelastic relaxtation time), the amplitude of the DA solitary waves decays slowly with time with the effect of a small amount of dus...

  15. Oblique propagation of dust ion-acoustic solitary waves in a magnetized dusty pair-ion plasma

    CERN Document Server

    Misra, A P

    2013-01-01

    We study the linear and nonlinear properties of electrostatic waves in a magnetized pair-ion plasma with immobile positively charged dusts. For the obliquely propagating linear waves, a general dispersion relation is derived, from which it is shown that the low-frequency (in comparison with the negative-ion cyclotron frequency) long-wavelength "slow" and a "fast" modes can propagate as dust ion-acoustic (DIA) and dust ion-cyclotron (DIC)-like waves. The properties of these modes are analyzed with the effects of obliqueness of propagation $(\\theta)$, the negative to positive ion mass ratio $(m)$, the ratio of negative to positive ion temperatures $(T)$, the static magnetic field as well as the presence of charged dusts (characterized by the dust to negative-ion number density $\\delta$) in the plasma. In the nonlinear regime, a standard reductive perturbation technique is used to derive a Korteweg-de Vries (KdV) equation for the oblique DIA waves. We show that the KdV equation can admit either compressive or ra...

  16. Dust-acoustic solitary waves in a magnetized dusty plasma with nonthermal electrons and trapped ions

    CERN Document Server

    Misra, A P

    2014-01-01

    The nonlinear theory of electrostatic dust-acoustic (DA) waves in a magnetized dusty plasma consisting of negatively charged mobile dusts, nonthermal fast electrons and trapped ions with vortex-like distribution is revisited. Previous theory in the literature [Phys. Plasmas {\\bf 20}, 104505 (2013)] is rectified and put forward to include the effects of the external magnetic field, the adiabatic pressure of charged dusts as well as the obliqueness of propagation to the magnetic field. Using the reductive perturbation technique, a Korteweg-de Vries (KdV)-like equation is derived which governs the dynamics of the small-amplitude solitary waves in a magnetized dusty nonthermal plasma. It is found that due to the dust thermal pressure, there exists a critical value $(\\beta_c)$ of the nothermal parameter $\\beta (>1)$, denoting the percentage of energetic electrons, below which the DA solitary waves cease to propagate. The soliton solution (travelling wave) of the KdV-like equation is obtained, and is shown to be on...

  17. Landau damping effects on dust-acoustic solitary waves in a dusty negative-ion plasma

    CERN Document Server

    Barman, A

    2014-01-01

    The nonlinear theory of dust-acoustic waves (DAWs) with Landau damping is studied in an unmagnetized dusty negative-ion plasma in the extreme conditions when the free electrons are absent. The cold massive charged dusts are described by fluid equations, whereas the two-species of ions (positive and negative) are described by the kinetic Vlasov equations. A Korteweg de-Vries (KdV) equation with Landau damping, governing the dynamics of weakly nonlinear and weakly dispersive DAWs, is derived following Ott and Sudan [Phys. Fluids {\\bf 12}, 2388 (1969)]. It is shown that for some typical laboratory and space plasmas, the Landau damping (and the nonlinear) effects are more pronounced than the finite Debye length (dispersive) effects for which the KdV soliton theory is not applicable to DAWs in dusty pair-ion plasmas. The properties of the linear phase velocity, solitary wave amplitudes (in presence and absence of the Landau damping) as well as the Landau damping rate are studied with the effects of the positive io...

  18. A Centerless Virasoro Algebra of Master Symmetries for the Ablowitz-Ladik Hierarchy

    Directory of Open Access Journals (Sweden)

    Luc Haine

    2013-12-01

    Full Text Available We show that the (semi-infinite Ablowitz-Ladik (AL hierarchy admits a centerless Virasoro algebra of master symmetries in the sense of Fuchssteiner [Progr. Theoret. Phys. 70 (1983, 1508-1522]. An explicit expression for these symmetries is given in terms of a slight generalization of the Cantero, Moral and Velázquez (CMV matrices [Linear Algebra Appl. 362 (2003, 29-56] and their action on the tau-functions of the hierarchy is described. The use of the CMV matrices turns out to be crucial for obtaining a Lax pair representation of the master symmetries. The AL hierarchy seems to be the first example of an integrable hierarchy which admits a full centerless Virasoro algebra of master symmetries, in contrast with the Toda lattice and Korteweg-de Vries hierarchies which possess only ''half of'' a Virasoro algebra of master symmetries, as explained in Adler and van Moerbeke [Duke Math. J. 80 (1995, 863-911], Damianou [Lett. Math. Phys. 20 (1990, 101-112] and Magri and Zubelli [Comm. Math. Phys. 141 (1991, 329-351].

  19. Experimental investigation of flow induced dust acoustic shock waves in a complex plasma

    Energy Technology Data Exchange (ETDEWEB)

    Jaiswal, S., E-mail: surabhijaiswal73@gmail.com; Bandyopadhyay, P.; Sen, A. [Institute for Plasma Research, Bhat, Gandhinagar, Gujarat 382428 (India)

    2016-08-15

    We report on experimental observations of flow induced large amplitude dust-acoustic shock waves in a complex plasma. The experiments have been carried out in a Π shaped direct current glow discharge experimental device using kaolin particles as the dust component in a background of Argon plasma. A strong supersonic flow of the dust fluid is induced by adjusting the pumping speed and neutral gas flow into the device. An isolated copper wire mounted on the cathode acts as a potential barrier to the flow of dust particles. A sudden change in the gas flow rate is used to trigger the onset of high velocity dust acoustic shocks whose dynamics are captured by fast video pictures of the evolving structures. The physical characteristics of these shocks are delineated through a parametric scan of their dynamical properties over a range of flow speeds and potential hill heights. The observed evolution of the shock waves and their propagation characteristics are found to compare well with model numerical results based on a modified Korteweg-de-Vries-Burgers type equation.

  20. Solar wind implication on dust ion acoustic rogue waves

    Energy Technology Data Exchange (ETDEWEB)

    Abdelghany, A. M., E-mail: asmaaallah20@yahoo.com; Abd El-Razek, H. N., E-mail: hosam.abdelrazek@yahoo.com; El-Labany, S. K., E-mail: skellabany@hotmail.com [Theoretical Physics Group, Department of Physics, Faculty of Science, Damietta University, New Damietta 34517 (Egypt); Moslem, W. M., E-mail: wmmoslem@hotmail.com [Department of Physics, Faculty of Science, Port Said University, Port Said 42521 (Egypt); Centre for Theoretical Physics, The British University in Egypt (BUE), El-Shorouk City, Cairo (Egypt)

    2016-06-15

    The relevance of the solar wind with the magnetosphere of Jupiter that contains positively charged dust grains is investigated. The perturbation/excitation caused by streaming ions and electron beams from the solar wind could form different nonlinear structures such as rogue waves, depending on the dominant role of the plasma parameters. Using the reductive perturbation method, the basic set of fluid equations is reduced to modified Korteweg-de Vries (KdV) and further modified (KdV) equation. Assuming that the frequency of the carrier wave is much smaller than the ion plasma frequency, these equations are transformed into nonlinear Schrödinger equations with appropriate coefficients. Rational solution of the nonlinear Schrödinger equation shows that rogue wave envelopes are supported by the present plasma model. It is found that the existence region of rogue waves depends on the dust-acoustic speed and the streaming temperatures for both the ions and electrons. The dependence of the maximum rogue wave envelope amplitude on the system parameters has been investigated.

  1. Bifurcation analysis for ion acoustic waves in a strongly coupled plasma including trapped electrons

    Science.gov (United States)

    El-Labany, S. K.; El-Taibany, W. F.; Atteya, A.

    2018-02-01

    The nonlinear ion acoustic wave propagation in a strongly coupled plasma composed of ions and trapped electrons has been investigated. The reductive perturbation method is employed to derive a modified Korteweg-de Vries-Burgers (mKdV-Burgers) equation. To solve this equation in case of dissipative system, the tangent hyperbolic method is used, and a shock wave solution is obtained. Numerical investigations show that, the ion acoustic waves are significantly modified by the effect of polarization force, the trapped electrons and the viscosity coefficients. Applying the bifurcation theory to the dynamical system of the derived mKdV-Burgers equation, the phase portraits of the traveling wave solutions of both of dissipative and non-dissipative systems are analyzed. The present results could be helpful for a better understanding of the waves nonlinear propagation in a strongly coupled plasma, which can be produced by photoionizing laser-cooled and trapped electrons [1], and also in neutron stars or white dwarfs interior.

  2. Planar and Nonplanar Solitary Waves in a Four-Component Relativistic Degenerate Dense Plasma

    Directory of Open Access Journals (Sweden)

    M. R. Hossen

    2014-01-01

    degenerate electrons, nonrelativistic degenerate ions, and arbitrarily charged static heavy ions has been investigated theoretically. The Korteweg-de Vries (K-dV equation has been derived by employing the reductive perturbation method. Their solitary wave solution is obtained and numerically analyzed in case of both planar and nonplanar (cylindrical and spherical geometry. It has been observed that the ion-acoustic (IA and modified ion-acoustic (mIA solitary waves have been significantly changed due to the effects of degenerate plasma pressure and number densities of the arbitrarily charged heavy ions. It has been also found that properties of planar K-dV solitons are quite different from those of nonplanar K-dV solitons. There are numerous variations in case of mIA solitary waves due to the polarity of heavy ions. The basic features and the underlying physics of IA and mIA solitary waves, which are relevant to some astrophysical compact objects, are briefly discussed.

  3. Classification of Dark Modified KdV Equation

    Science.gov (United States)

    Xiong, Na; Lou, Sen-Yue; Li, Biao; Chen, Yong

    2017-07-01

    The dark Korteweg-de Vries (KdV) systems are defined and classified by Kupershmidt sixteen years ago. However, there is no other classifications for other kinds of nonlinear systems. In this paper, a complete scalar classification for dark modified KdV (MKdV) systems is obtained by requiring the existence of higher order differential polynomial symmetries. Different to the nine classes of the dark KdV case, there exist twelve independent classes of the dark MKdV equations. Furthermore, for the every class of dark MKdV system, there is a free parameter. Only for a fixed parameter, the dark MKdV can be related to dark KdV via suitable Miura transformation. The recursion operators of two classes of dark MKdV systems are also given. Supported by the Global Change Research Program of China under Grant No. 2015Cb953904, National Natural Science Foundation of China under Grant Nos. 11675054, 11435005, 11175092, and 11205092 and Shanghai Knowledge Service Platform for Trustworthy Internet of Things (No. ZF1213) and K. C. Wong Magna Fund in Ningbo University

  4. Radiating dispersive shock waves in non-local optical media.

    Science.gov (United States)

    El, Gennady A; Smyth, Noel F

    2016-03-01

    We consider the step Riemann problem for the system of equations describing the propagation of a coherent light beam in nematic liquid crystals, which is a general system describing nonlinear wave propagation in a number of different physical applications. While the equation governing the light beam is of defocusing nonlinear Schrödinger (NLS) equation type, the dispersive shock wave (DSW) generated from this initial condition has major differences from the standard DSW solution of the defocusing NLS equation. In particular, it is found that the DSW has positive polarity and generates resonant radiation which propagates ahead of it. Remarkably, the velocity of the lead soliton of the DSW is determined by the classical shock velocity. The solution for the radiative wavetrain is obtained using the Wentzel-Kramers-Brillouin approximation. It is shown that for sufficiently small initial jumps the nematic DSW is asymptotically governed by a Korteweg-de Vries equation with the fifth-order dispersion, which explicitly shows the resonance generating the radiation ahead of the DSW. The constructed asymptotic theory is shown to be in good agreement with the results of direct numerical simulations.

  5. The lifecycle of axisymmetric internal solitary waves

    Directory of Open Access Journals (Sweden)

    J. M. McMillan

    2010-09-01

    Full Text Available The generation and evolution of solitary waves by intrusive gravity currents in an approximate two-layer fluid with equal upper- and lower-layer depths is examined in a cylindrical geometry by way of theory and numerical simulations. The study is limited to vertically symmetric cases in which the density of the intruding fluid is equal to the average density of the ambient. We show that even though the head height of the intrusion decreases, it propagates at a constant speed well beyond 3 lock radii. This is because the strong stratification at the interface supports the formation of a mode-2 solitary wave that surrounds the intrusion head and carries it outwards at a constant speed. The wave and intrusion propagate faster than a linear long wave; therefore, there is strong supporting evidence that the wave is indeed nonlinear. Rectilinear Korteweg-de Vries theory is extended to allow the wave amplitude to decay as r-p with p=½ and the theory is compared to the observed waves to demonstrate that the width of the wave scales with its amplitude. After propagating beyond 7 lock radii the intrusion runs out of fluid. Thereafter, the wave continues to spread radially at a constant speed, however, the amplitude decreases sufficiently so that linear dispersion dominates and the amplitude decays with distance as r-1.

  6. Enhanced stability of car-following model upon incorporation of short-term driving memory

    Science.gov (United States)

    Liu, Da-Wei; Shi, Zhong-Ke; Ai, Wen-Huan

    2017-06-01

    Based on the full velocity difference model, a new car-following model is developed to investigate the effect of short-term driving memory on traffic flow in this paper. Short-term driving memory is introduced as the influence factor of driver's anticipation behavior. The stability condition of the newly developed model is derived and the modified Korteweg-de Vries (mKdV) equation is constructed to describe the traffic behavior near the critical point. Via numerical method, evolution of a small perturbation is investigated firstly. The results show that the improvement of this new car-following model over the previous ones lies in the fact that the new model can improve the traffic stability. Starting and breaking processes of vehicles in the signalized intersection are also investigated. The numerical simulations illustrate that the new model can successfully describe the driver's anticipation behavior, and that the efficiency and safety of the vehicles passing through the signalized intersection are improved by considering short-term driving memory.

  7. Qualitative analysis of the positron-acoustic waves in electron-positron-ion plasmas with κ deformed Kaniadakis distributed electrons and hot positrons

    Science.gov (United States)

    Saha, Asit; Tamang, Jharna

    2017-08-01

    Qualitative analysis of the positron acoustic (PA) waves in a four-component plasma system consisting of static positive ions, mobile cold positron, and Kaniadakis distributed hot positrons and electrons is investigated. Using the reductive perturbation technique, the Korteweg-de Vries (K-dV) equation and the modified KdV equation are derived for the PA waves. Variations of the total energy of the conservative systems corresponding to the KdV and mKdV equations are presented. Applying numerical computations, effect of parameter (κ), number density ratio (μ1) of electrons to ions and number density (μ2) of hot positrons to ions, and speed (U) of the traveling wave are discussed on the positron acoustic solitary wave solutions of the KdV and mKdV equations. Furthermore, it is found that the parameter κ has no effect on the solitary wave solution of the KdV equation, whereas it has significant effect on the solitary wave solution of the modified KdV equation. Considering an external periodic perturbation, the perturbed dynamical systems corresponding to the KdV and mKdV equations are analyzed by employing three dimensional phase portrait analysis, time series analysis, and Poincare section. Chaotic motions of the perturbed PA waves occur through the quasiperiodic route to chaos.

  8. Long-Time Asymptotics of a Box-Type Initial Condition in a Viscous Fluid Conduit

    Science.gov (United States)

    Franco, Nevil; Webb, Emily; Maiden, Michelle; Hoefer, Mark; El, Gennady

    2017-11-01

    The initial value problem for a localized hump disturbance is fundamental to dispersive nonlinear waves, beginning with studies of the celebrated, completely integrable Korteweg-de Vries equation. However, understanding responses to similar disturbances in many realistic dispersive wave systems is more complicated because they lack the mathematical property of complete integrability. This project applies Whitham nonlinear wave modulation theory to estimate how a viscous fluid conduit evolves this classic initial value problem. Comparisons between theory, numerical simulations, and experiments are presented. The conduit system consists of a viscous fluid column (glycerol) and a diluted, dyed version of the same fluid introduced to the column through a nozzle at the bottom. Steady injection and the buoyancy of the injected fluid leads to the eventual formation of a stable fluid conduit. Within this structure, a one hump disturbance is introduced and is observed to break up into a quantifiable number of solitons. This structure's experimental evolution is to Whitham theory and numerical simulations of a long-wave interfacial model equation. The method presented is general and can be applied to other dispersive nonlinear wave systems. Please email me, as I am the submitter.

  9. Initial-value problem for the Gardner equation applied to nonlinear internal waves

    Science.gov (United States)

    Rouvinskaya, Ekaterina; Kurkina, Oxana; Kurkin, Andrey; Talipova, Tatiana; Pelinovsky, Efim

    2017-04-01

    The Gardner equation is a fundamental mathematical model for the description of weakly nonlinear weakly dispersive internal waves, when cubic nonlinearity cannot be neglected. Within this model coefficients of quadratic and cubic nonlinearity can both be positive as well as negative, depending on background conditions of the medium, where waves propagate (sea water density stratification, shear flow profile) [Rouvinskaya et al., 2014, Kurkina et al., 2011, 2015]. For the investigation of weakly dispersive behavior in the framework of nondimensional Gardner equation with fixed (positive) sign of quadratic nonlinearity and positive or negative cubic nonlinearity {eq1} partial η/partial t+6η( {1± η} )partial η/partial x+partial ^3η/partial x^3=0, } the series of numerical experiments of initial-value problem was carried out for evolution of a bell-shaped impulse of negative polarity (opposite to the sign of quadratic nonlinear coefficient): {eq2} η(x,t=0)=-asech2 ( {x/x0 } ), for which amplitude a and width x0 was varied. Similar initial-value problem was considered in the paper [Trillo et al., 2016] for the Korteweg - de Vries equation. For the Gardner equation with different signs of cubic nonlinearity the initial-value problem for piece-wise constant initial condition was considered in detail in [Grimshaw et al., 2002, 2010]. It is widely known, for example, [Pelinovsky et al., 2007], that the Gardner equation (1) with negative cubic nonlinearity has a family of classic solitary wave solutions with only positive polarity,and with limiting amplitude equal to 1. Therefore evolution of impulses (2) of negative polarity (whose amplitudes a were varied from 0.1 to 3, and widths at the level of a/2 were equal to triple width of solitons with the same amplitude for a 1) was going on a universal scenario with the generation of nonlinear Airy wave. For the Gardner equation (1) with the positive cubic nonlinearity coefficient there exist two one-parametric families of

  10. Head-on collision of ion acoustic solitary waves in electron-positron-ion nonthermal plasmas for weakly and highly relativistic regimes

    Science.gov (United States)

    Alam, M. S.; Hafez, M. G.; Talukder, M. R.; Hossain Ali, M.

    2017-07-01

    A comparative study of the interactions between nonlinear ion acoustic solitary waves (IASWs) propagating toward each other, and the electrostatic nonlinear propagation of IASWs, both for the weakly and relativistic regimes consisting of relativistic warm ions, nonthermal electrons, and positrons, is carried out. Two-sided Korteweg-de Vries (KdV) equations are derived using the extended Poincaré-Lighthill-Kuo (PLK) method to reveal the physical issues concerned. The effects of positron concentration, ion-electron temperature ratio, electron-positron temperature ratio, relativistic streaming factor, the population of electron, and positron nonthermality on the electrostatic resonances and their phase shifts are investigated for both regimes. It is found that the plasma parameters significantly modify the phase shifts, electrostatic resonances, hump-shaped electrostatic potential profiles, and the electric fields on the nonlinear propagation characteristics of IASWs. The results obtained may be useful for clarifications of interaction between IASWs in astrophysical and laboratory plasmas, especially in pulsar magnetosphere, laser produced, inertial confinement plasmas, and pulsar relativistic winds with supernova ejecta that produce nonthermal electrons, positrons, and relativistic ions.

  11. Dust ion-acoustic shocks in quantum dusty pair-ion plasmas

    CERN Document Server

    Misra, A P

    2008-01-01

    The formation of dust ion-acoustic shocks (DIASs) in a four-component quantum plasma whose constituents are electrons, both positive and negative ions and immobile charged dust grains, is studied. The effects of both the dissipation due to kinematic viscosity and the dispersion caused by the charge separation as well as the quantum tunneling due to the Bohm potential are taken into account. The propagation of small but finite amplitude dust ion-acoustic waves (DIAWs) is governed by the Korteweg-de Vries-Burger (KdVB) equation which exhibits both oscillatory and monotonic shocks depending not only on the viscosity parameters, but also on the quantum parameter H (the ratio of the electron plasmon to the electron Fermi energy) and the positive to negative ion density ratio. Large amplitude stationary shocks are recovered for a Mach number exceeding its critical value. Unlike the small amplitude shocks, quite a smaller value of the viscosity parameter, H and the density ratio may lead to the large amplitude monot...

  12. Ad-hoc KEEN-type Waves and their Occasional Resemblance to KdV Waveforms

    Science.gov (United States)

    Tyshetskiy, Yuriy; Afeyan, Bedros

    2005-10-01

    Nonlinear kinetic waves of the KEEN type [1] but constructed with two BGK recipes are tested with 1D Vlasov-Poisson simulation (1DVPS). One is that of Allis [2] as modified by Johnston (unpublished), the other is that of Eliasson and Shukla [3]. Strong kinetic waves survive well, but not weaker ones. The potential wave trains resemble those from the Korteweg-deVries equation. This proves to be natural when charge density variation with electrostatic potential is like a quadratic polynomial. For expositions on the physics of ponderomotively driven KEEN waves, consult presentations by Afeyan and Savchenko, this conference. (Part of this work was performed under the auspices of the U.S. Department of Energy under grant number DE-FG03-NA00059.) [1] B. Afeyan et al., ``Kinetic Electrostatic Electron Nonlinear (KEEN) Waves and their interactions driven by the ponderomotive force of crossing laser beams'', Proc. IFSA (Inertial Fusion Sciences and Applications 2003, Monterey, CA), 213, B. Hammel, D. Meyerhofer, J. Meyer-ter-Vehn and H. Azechi, editors, American Nuclear Society, 2004. [2] W.P. Allis, paper 3 (pp.21-42), in ``In Honor of Philip M. Morse'', ed. H. Feshbach and K. Ingard, MIT Press (1969). [3] B. Eliasson and P.K. Shukla, Phys. Rev. E 71, 046402 (2005)

  13. KdV cnoidal waves in a traffic flow model with periodic boundaries

    Science.gov (United States)

    Hattam, L.

    2017-06-01

    An optimal-velocity (OV) model describes car motion on a single lane road. In particular, near to the boundary signifying the onset of traffic jams, this model reduces to a perturbed Korteweg-de Vries (KdV) equation using asymptotic analysis. Previously, the KdV soliton solution has then been found and compared to numerical results (see Muramatsu and Nagatani [1]). Here, we instead apply modulation theory to this perturbed KdV equation to obtain at leading order, the modulated cnoidal wave solution. At the next order, the Whitham equations are derived, which have been modified due to the equation perturbation terms. Next, from this modulation system, a family of spatially periodic cnoidal waves are identified that characterise vehicle headway distance. Then, for this set of solutions, we establish the relationship between the wave speed, the modulation term and the driver sensitivity. This analysis is confirmed with comparisons to numerical solutions of the OV model. As well, the long-time behaviour of these solutions is investigated.

  14. Nonlinear waves in viscoelastic magnetized complex astroplasmas with polarized dust-charge variations

    Directory of Open Access Journals (Sweden)

    Papari Das

    2018-01-01

    Full Text Available A nonextensive nonthermal magnetized viscoelastic astrofluid, compositionally containing nonthermal electrons and ions together with massive polarized dust micro-spherical grains of variable electric charge, is allowed to endure weakly nonlinear perturbation around its equilibrium. The nonextensivity originating from the large-scale non-local effects is included via the Tsallis thermo-statistical distribution laws describing the lighter species. Assuming the equilibrium as a homogeneous hydrostatic one, the dust polarization effects are incorporated via the conventional homogeneous polarization force law. The perturbed fluid model evolves as a unique conjugate pair of coupled extended Korteweg-de Vries (e-KdV equations. A constructed numerical tapestry shows the collective excitations of a new pair of distinct classes of nonlinear mode structures in new parametric space. The first family indicates periodic electrostatic compressive eigenmodes in the form of soliton-chains. Likewise, the second one reveals gravitational rarefactive solitary patterns. Their microphysical multi-parametric dependencies of the eigen-patterns are illustratively analyzed and bolstered. The paper ends up with some promising implications and applications in the astro-cosmo-plasmic context of wave-induced accretive triggering processes responsible for gravitationally bounded (gravito-condensed astro-structure formation, such as stellesimals, planetsimals, etc.

  15. Investigation of magnetic flux transport and shock formation in a staged Z-pinch

    Science.gov (United States)

    Narkis, J.; Rahman, H. U.; Wessel, F. J.; Beg, F. N.

    2017-10-01

    Target preheating is an integral component of magnetized inertial fusion in reducing convergence ratio. In the staged Z-pinch concept, it is achieved via one or more shocks. Previous work [Narkis et al., Phys. Plasmas 23, 122706 (2016)] found that shock formation in the target occurred earlier in higher-Z liners due to faster flux transport to the target/liner interface. However, a corresponding increase in magnitude of magnetic pressure was not observed, and target implosion velocity (and therefore shock strength) remained unchanged. To investigate other means of increasing the magnitude of transported flux, a Korteweg-de Vries-Burgers equation from the 1-D single-fluid, resistive magnetohydrodynamic equations is obtained. Solutions to the nondispersive (i.e., Burgers) equation depend on nondimensional coefficients, whose dependence on liner density, temperature, etc., suggests an increase in target implosion velocity, and therefore shock strength, can be obtained by tailoring the mass of a single-liner gas puff to a double-liner configuration. In the selected test cases of 1-D simulated implosions of krypton on deuterium, the peak Mach number increased from ˜ 5 to ˜ 8 . While a notable increase was seen, Mach numbers exceeding 10 (implosion velocities exceeding ˜25 cm/μs) are necessary for adequate shock preheating.

  16. Convex and concave types of second baroclinic mode internal solitary waves

    Directory of Open Access Journals (Sweden)

    Y. J. Yang

    2010-11-01

    Full Text Available Two types of second baroclinic mode (mode-2 internal solitary waves (ISWs were found on the continental slope of the northern South China Sea. The convex waveform displaced the thermal structure upward in the upper layer and downward in the lower layer, causing a bulge in the thermocline. The concave waveform did the opposite, causing a constriction. A few concave waves were observed in the South China Sea, marking the first documentation of such waves. On the basis of the Korteweg-de Vries (K-dV equation, an analytical three-layer ocean model was used to study the characteristics of the two mode-2 ISW types. The analytical solution was primarily a function of the thickness of each layer and the density difference between the layers. Middle-layer thickness plays a key role in the resulting mode-2 ISW. A convex wave was generated when the middle-layer thickness was relatively thinner than the upper and lower layers, whereas only a concave wave could be produced when the middle-layer thickness was greater than half the water depth. In accordance with the K-dV equation, a positive and negative quadratic nonlinearity coefficient, α2, which is primarily dominated by the middle-layer thickness, resulted in convex and concave waves, respectively. The analytical solution showed that the wave propagation of a convex (concave wave has the same direction as the current velocity in the middle (upper or lower layer. Analysis of the three-layer ocean model properly reproduced the characteristics of the observed mode-2 ISWs in the South China Sea and provided a criterion for the existence of convex or concave waves. Concave waves were seldom seen because of the rarity of a stratified ocean with a thick middle layer. This analytical result agreed well with the observations.

  17. A method for computing unsteady fully nonlinear interfacial waves

    Science.gov (United States)

    Grue, John; André Friis, Helmer; Palm, Enok; Olav Rusås, Per

    1997-11-01

    We derive a time-stepping method for unsteady fully nonlinear two-dimensional motion of a two-layer fluid. Essential parts of the method are: use of Taylor series expansions of the prognostic equations, application of spatial finite difference formulae of high order, and application of Cauchy's theorem to solve the Laplace equation, where the latter is found to be advantageous in avoiding instability. The method is computationally very efficient. The model is applied to investigate unsteady trans-critical two-layer flow over a bottom topography. We are able to simulate a set of laboratory experiments on this problem described by Melville & Helfrich (1987), finding a very good agreement between the fully nonlinear model and the experiments, where they reported bad agreement with weakly nonlinear Korteweg de Vries theories for interfacial waves. The unsteady transcritical regime is identified. In this regime, we find that an upstream undular bore is generated when the speed of the body is less than a certain value, which somewhat exceeds the critical speed. In the remaining regime, a train of solitary waves is generated upstream. In both cases a corresponding constant level of the interface behind the body is developed. We also perform a detailed investigation of upstream generation of solitary waves by a moving body, finding that wave trains with amplitude comparable to the thickness of the thinner layer are generated. The results indicate that weakly nonlinear theories in many cases have quite limited applications in modelling unsteady transcritical two-layer flows, and that a fully nonlinear method in general is required.

  18. Long surface wave dynamics along a convex bottom

    Science.gov (United States)

    Didenkulova, Ira; Pelinovsky, Efim; Soomere, Tarmo

    2009-07-01

    Long linear wave transformation in a basin of varying depth is studied for a case of a convex bottom profile h(x) ˜ x4/3. This bottom geometry provides the "nonreflecting" wave propagation at least in the framework of the one-dimensional shallow water equation. In this case, shoaling effects are very strong and wave reflection occurs in the immediate vicinity of the shoreline. The existence of traveling wave solutions (which propagate without reflection) in this geometry is established through construction of a 1:1 transformation of the general 1-D wave equation to the analogous wave equation with constant coefficients. The general solution of the Cauchy problem consists of two traveling waves propagating in opposite directions and allows a detailed description of the wavefield (vertical displacement and depth-averaged flow). It is found that generally a zone of weak current is formed between these two waves. Waves are reflected from the coastline so that their profile is inverted with respect to the calm water surface. Long-wave runup on a beach with this profile is studied for the sine pulse, Korteweg-de Vries soliton, and N wave. It is shown that in certain cases the runup height along the convex profile is considerably larger than for beaches with a linear slope. The analysis of wave reflection from the border of a shallow coastal area of constant depth and a section with the convex profile shows that a transmitted wave always has a sign-variable shape. Results of the wave transformation above the convex beach and beaches following a general power law are compared. This simplified model demonstrates the potential importance of the tsunami wave transformation along convex beaches.

  19. Generation and evolution of internal waves in Banderas Bay, Jalisco-Nayarit, Mexico.

    Science.gov (United States)

    Plata, L. J.; Anatoliy, F.; Iryna, T.; Carlos, V.; Liza, K.; César, M.

    2007-05-01

    The characteristics of internal waves in Banderas Bay (Mexico) were determined by means of data from oceanographical measurements carried on spring and winter during the years 2001 and 2003. The intense fluctuations in the fields of temperature and salinity obtained from a fast oceanographical survey with an undulating CTD on April, 2001, give evidence of the presence and propagation of an internal waves' field. With the help of a bathymetric chart elaborated from a survey carried on in March and May, 2002, we found that the submarine canyon close to the southern coast of the bay, from Cabo Corrientes to Mismaloya, acts like a filter that reflects the diurnal internal tide and allows only the entrance of semidiurnal internal tide. The results of a special experiment measuring the spatiotemporal parameters of internal waves on the wide continental shelf of northwestern Banderas Bay are discussed. The oceanographical measurements consisted of: a) a fast survey with an undulating CTD along a transect perpendicular to the coast, (b) the towing of an array of temperature and depth sensors several times over the continental shelf along transects perpendicular to the coast, and (c) time series of velocity components registered by an acoustic Doppler current profiler placed on the seabed of the bay at 28 m depth. The presence of internal waves generated by semidiurnal tide and corresponding to the second normal oscillation mode (according to the linear theory of internal waves) was determined. Analysis of the data showed that, in the study area, the internal waves generated over the continental slope by the barotropic tide have the shape of an oscillatory bore, which quickly disintegrates during their propagation shoreward, producing short nonlinear waves that dissipate close to the coast, and intense vertical mixing of the whole water column. The interpretation of the results was based on the linear and nonlinear (Korteweg-de Vries equation) theories of internal waves.

  20. Detection of Moving Targets Using Soliton Resonance Effect

    Science.gov (United States)

    Kulikov, Igor K.; Zak, Michail

    2013-01-01

    The objective of this research was to develop a fundamentally new method for detecting hidden moving targets within noisy and cluttered data-streams using a novel "soliton resonance" effect in nonlinear dynamical systems. The technique uses an inhomogeneous Korteweg de Vries (KdV) equation containing moving-target information. Solution of the KdV equation will describe a soliton propagating with the same kinematic characteristics as the target. The approach uses the time-dependent data stream obtained with a sensor in form of the "forcing function," which is incorporated in an inhomogeneous KdV equation. When a hidden moving target (which in many ways resembles a soliton) encounters the natural "probe" soliton solution of the KdV equation, a strong resonance phenomenon results that makes the location and motion of the target apparent. Soliton resonance method will amplify the moving target signal, suppressing the noise. The method will be a very effective tool for locating and identifying diverse, highly dynamic targets with ill-defined characteristics in a noisy environment. The soliton resonance method for the detection of moving targets was developed in one and two dimensions. Computer simulations proved that the method could be used for detection of singe point-like targets moving with constant velocities and accelerations in 1D and along straight lines or curved trajectories in 2D. The method also allows estimation of the kinematic characteristics of moving targets, and reconstruction of target trajectories in 2D. The method could be very effective for target detection in the presence of clutter and for the case of target obscurations.

  1. Linear and non-linear propagation of electrostatic positron-acoustic waves and envelope solitons in 4-component quantum plasma containing relativistically degenerate electrons and positrons

    Science.gov (United States)

    Ahmad, Rashid; Gul, Nabi; Adnan, Muhammad; Tribeche, Mouloud; Khattak, Fida Younus

    2017-04-01

    A hydrodynamic model is employed to investigate the linear and non-linear propagation of electrostatic positron acoustic waves (EPAWs) in a 4-component relativistic-degenerate electron-positron-ion plasma. The plasma constituents are cold positrons, hot relativistic-degenerate electrons and positrons, and cold static ions in the background. The hot electrons and positrons are treated as inertialess, and the cold positrons provide the inertia while the restoring force comes from the hot species. A dispersion relation for low-frequency EPAWs is derived. It is observed that an increase in the relative density of hot positrons to cold positrons and relativistic effects tend to reduce the speed of the EPAWs. Employing the standard Reductive Perturbation Technique, a Korteweg de Vries (KdV)-type equation is derived, and the existence of KdV solitons is demonstrated. In this case, an increase in the relative density of hot to cold positrons and relativistic effects decreases both the amplitude and width of the solitons. Furthermore, a Non-Linear Schrödinger (NLS) equation is also derived. The variation in the group velocity shows less change with the wavenumber for the higher concentration of positrons and also with the stronger relativistic effects. The interchange in the behaviour of group velocity with the positron concentration is observed for values k > 1. The growth rate of modulation instability is derived, and its dependence on the positron concentration and relativistic effects are discussed. The relativistic effects reduce the stability region while the growth rate is enhanced while moving from weak-relativistic to ultra-relativistic cases. The hot positron concentration makes the wave modulationally stable for an extended region of the wavenumber k. The solution of the NLS equation admits the existence of both bright and dark envelope solitons. The profiles of the envelope solitons show inverse dependence on the positron concentration and on the relativistic

  2. Korteweg–de Vries hierarchy using the method of base equations

    Indian Academy of Sciences (India)

    Author Affiliations. Subhendu Chakrabarti1 J Pal2 B Talukdar1. Department of Physics, Visva-Bharati University, Santiniketan 731 235, India; Department of Physics, Bolpur College, Bolpur 731 204, India ...

  3. Juhtimisguru: vaja on haridust ja ettevõtlikkust / Manfred Kets de Vries ; intervjueerinud Endrik Randoja

    Index Scriptorium Estoniae

    Vries, Manfred Kets de

    2010-01-01

    Maailmakuulus koolitaja vastab küsimustele, mis on sel aastal juhtide mõtetes kõige põletavamad teemad, kas coaching ja mentorlus on juhtimise arendamise uus kvaliteet, kuidas tulemuslikkust tunnustada, mida juhid peaksid tegema, et uut kasvu ära kasutada

  4. Putin tegi Gruusias järgmise manöövri / Sirje Rank

    Index Scriptorium Estoniae

    Rank, Sirje, 1966-

    2008-01-01

    Venemaa president Vladimir Putin andis korralduse alustada Gruusiaga kõnelusi kaubandusembargo, viisapiirangute ja muude sanktsioonide lõpetamiseks, kuid Gruusia poliitikud suhtuvad sellesse umbusuga

  5. De Vries-Weber gain control and dark adaptation in human vision

    NARCIS (Netherlands)

    Bouman, M.A.

    2002-01-01

    Thresholds for seeing light from a stimulus are determined by a mechanism that pairs subliminal excitations from both halves of a twin unit. Such excitations stem from a package of k ≥ 1 receptor responses. A half-unit contains one red or one green cone and P rods. The receptor's "Weber machine"

  6. Korteweg–de Vries hierarchy using the method of base equations

    Indian Academy of Sciences (India)

    ... of equations discovered by Lax often goes by the name KdV hierarchy and is generated by making use of the recursion operator [2] ... a kernel characterized by only the bound-state spectrum of v(x). The t-evolution of the kernel enters through the normalization constant. For the case of a single-soliton solution at a wave ...

  7. The perceptions of rural women doctors about their work | De Vries ...

    African Journals Online (AJOL)

    Conclusions: Some of the themes identified in this study agreed with international research, e.g. the importance of a job for the spouse, family considerations including the choice to specialise, and balancing responsibilities at home and work. The advantage of accommodation close to the hospital is a them that has not been ...

  8. Religion: Beyond a Concept edited by Hent de Vries, New York: Fordham University Press, 2008 (Book Review)

    OpenAIRE

    Bigger, Stephen

    2010-01-01

    This large collection of 43 papers (soft-covered), some original and some reprinted, on religion’s past, present and future is the result of collaboration under the aegis of The Netherlands Organisation for Scientific Research, edited by Hent de Vreis who holds Professorial positions in Baltimore, Amsterdam and Paris. There are 45 contributors to a work in seven parts: What is Religion?; Religion and Philosophy; Methods of Instruction and Comparison; Emerging Contexts; Religion, Politics and ...

  9. Fermi-Pasta-Ulam, solitons and the fabric of nonlinear and computational science: History, synergetics, and visiometricsa)

    Science.gov (United States)

    Zabusky, Norman J.

    2005-03-01

    This paper is mostly a history of the early years of nonlinear and computational physics and mathematics. I trace how the counterintuitive result of near-recurrence to an initial condition in the first scientific digital computer simulation led to the discovery of the soliton in a later computer simulation. The 1955 report by Fermi, Pasta, and Ulam (FPU) described their simulation of a one-dimensional nonlinear lattice which did not show energy equipartition. The 1965 paper by Zabusky and Kruskalshowed that the Korteweg-de Vries (KdV) nonlinear partial differential equation, a long wavelength model of the α-lattice (or cubic nonlinearity), derived by Kruskal, gave quantitatively the same results obtained by FPU. In 1967, Zabusky and Deem showed that a localized short wavelength initial excitation (then called an "optical" and now a "zone-boundary mode" excitation ) of the α-lattice revealed "n-curve" coherent states. If the initial amplitude was sufficiently large energy equipartition followed in a short time. The work of Kruskal and Miura (KM), Gardner and Greene (GG), and myself led to the appreciation of the infinity of denumerable invariants (conservation laws) for Hamiltonian systems and to a procedure by GGKM in 1967 for solving KdV exactly. The nonlinear science field exponentiated in diversity of linkages (as described in Appendix A). Included were pure and applied mathematics and all branches of basic and applied physics, including the first nonhydrodynamic application to optical solitons, as described in a brief essay (Appendix B) by Hasegawa. The growth was also manifest in the number of meetings held and institutes founded, as described briefly in Appendix D. Physicists and mathematicians in Japan, USA, and USSR (in the latter two, people associated with plasma physics) contributed to the diversification of the nonlinear paradigm which continues worldwide to the present. The last part of the paper (and Appendix C) discuss visiometrics: the

  10. Fermi-Pasta-Ulam, solitons and the fabric of nonlinear and computational science: history, synergetics, and visiometrics.

    Science.gov (United States)

    Zabusky, Norman J

    2005-03-01

    This paper is mostly a history of the early years of nonlinear and computational physics and mathematics. I trace how the counterintuitive result of near-recurrence to an initial condition in the first scientific digital computer simulation led to the discovery of the soliton in a later computer simulation. The 1955 report by Fermi, Pasta, and Ulam (FPU) described their simulation of a one-dimensional nonlinear lattice which did not show energy equipartition. The 1965 paper by Zabusky and Kruskalshowed that the Korteweg-de Vries (KdV) nonlinear partial differential equation, a long wavelength model of the alpha-lattice (or cubic nonlinearity), derived by Kruskal, gave quantitatively the same results obtained by FPU. In 1967, Zabusky and Deem showed that a localized short wavelength initial excitation (then called an "optical" and now a "zone-boundary mode" excitation ) of the alpha-lattice revealed "n-curve" coherent states. If the initial amplitude was sufficiently large energy equipartition followed in a short time. The work of Kruskal and Miura (KM), Gardner and Greene (GG), and myself led to the appreciation of the infinity of denumerable invariants (conservation laws) for Hamiltonian systems and to a procedure by GGKM in 1967 for solving KdV exactly. The nonlinear science field exponentiated in diversity of linkages (as described in Appendix A). Included were pure and applied mathematics and all branches of basic and applied physics, including the first nonhydrodynamic application to optical solitons, as described in a brief essay (Appendix B) by Hasegawa. The growth was also manifest in the number of meetings held and institutes founded, as described briefly in Appendix D. Physicists and mathematicians in Japan, USA, and USSR (in the latter two, people associated with plasma physics) contributed to the diversification of the nonlinear paradigm which continues worldwide to the present. The last part of the paper (and Appendix C) discuss visiometrics: the

  11. On shallow water waves in a medium with time-dependent

    Directory of Open Access Journals (Sweden)

    Hamdy I. Abdel-Gawad

    2015-07-01

    Full Text Available In this paper, we studied the progression of shallow water waves relevant to the variable coefficient Korteweg–de Vries (vcKdV equation. We investigated two kinds of cases: when the dispersion and nonlinearity coefficients are proportional, and when they are not linearly dependent. In the first case, it was shown that the progressive waves have some geometric structures as in the case of KdV equation with constant coefficients but the waves travel with time dependent speed. In the second case, the wave structure is maintained when the nonlinearity balances the dispersion. Otherwise, water waves collapse. The objectives of the study are to find a wide class of exact solutions by using the extended unified method and to present a new algorithm for treating the coupled nonlinear PDE’s.

  12. The Guiding Light: Vri/uvby & Tio Photometry Of The Chromospherically Active & Spotted Binary System Im Peg - The Guide-star For The Gravity Probe-b Mission

    Science.gov (United States)

    Zellem, Robert; Guinan, E.; Messina, S.; Wasatonic, R.; McCook, G.

    2007-12-01

    We report on the starspot and chromospheric properties of IM Pegasi - the guide star of the Gravity Probe B (GP-B) satellite. GP-B's mission is to measure two predicted consequences of General Relativity - frame-dragging and geodetic effects, via its extremely precise onboard gyroscopes. IM Peg was selected as the mission's guide star as it is not only bright enough to be seen with GP-B's onboard optical telescope but it is also a bright radio source. Thus, ground-based radio telescope observations can easily and accurately correct for IM Peg's motions in space. However, IM Peg is a chomospherically active binary system with a luminous K2 III primary star showing rotationally modulated (Prot 24.5 days) light variations from starspots. The starspots can cause problems as GP-B can erroneously interpret a change in starspot coverage (and corresponding shifts in the light center) as the star's movement. This apparent shift can also be exacerbated by possible changes in the light-center of the binary system arising from changes in the light balance with the fainter dK component. Since 2000 we have carried out multi-band high-precision photoelectric photometry of IM Peg to determine its activity and starspot coverage. Our photometry uses Strömgren uvby filters, VRCIC filters and TiO (719/755 nm ) narrow-band filter sets. Measurements were made relative to neaby comparsion & check stars using a robotic 0.8-m telescope (located in AZ) and 0.25-m telescope (located in PA). The TiO- and multi-band continuum photometry constrains the starspot areas, temperatures and distributions. The photometry is being modeled to determine the effects of changing starspot areas and distributions on the light center of the binary. The results of our analysis and possible impacts on the GP-B Mission will be discussed. This research is supported by NSF/RUI Grants AST- 0507536 and AST- 0507542 which we gratefully acknowledge.

  13. Vooral een probleem in de wintermaanden: Biologische middelen werken preventief tegen Botrytis in cyclamen (interview met Jantineke Hofland-Zijlstra, m.m.w. van Rozemarijn de Vries)

    NARCIS (Netherlands)

    Arkesteijn, M.; Hofland-Zijlstra, J.D.; Vries, de R.S.M.

    2012-01-01

    Botrytis is vooral in de maanden november tot en met januari een probleem in de cyclamenketen. In die tijd zorgt de schimmelziekte voor bladaantasting. De infectie begint al in een vroeg stadium onder invloed van een aantal factoren en kan in de na-oogstfase leiden tot uitval. Daar komt bij dat

  14. Uniform strongly interacting soliton gas in the frame of the Nonlinear Schrodinger Equation

    Science.gov (United States)

    Gelash, Andrey; Agafontsev, Dmitry

    2017-04-01

    support of the Russian Science Foundation (Grand No. 14-22-00174) [1] D. Dutykh, E. Pelinovsky, Numerical simulation of a solitonic gas in kdv and kdv-bbm equations, Physics Letters A 378 (42) (2014) 3102-3110. [2] E. Shurgalina, E. Pelinovsky, Nonlinear dynamics of a soliton gas: Modified korteweg-de vries equation framework, Physics Letters A 380 (24) (2016) 2049-2053. [3] E. N. Pelinovsky, E. Shurgalina, A. Sergeeva, T. G. Talipova, G. El, R. H. Grimshaw, Two-soliton interaction as an elementary act of soliton turbulence in integrable systems, Physics Letters A 377 (3) (2013) 272-275 [4] J. Soto-Crespo, N. Devine, N. Akhmediev, Integrable turbulence and rogue waves: Breathers or solitons?, Physical review letters 116 (10) (2016) 103901. [5] D. S. Agafontsev, V. E. Zakharov, Integrable turbulence and formation of rogue waves, Nonlinearity 28 (8) (2015) 2791. [6] V. E. Zakharov, A. B. Shabat, Exact theory of two-dimensional self-focusing and one-dimensional self-modulation of waves in nonlinear media, Soviet Physics JETP 34 (1) (1972) 62. [7] V. Zakharov, A. Mikhailov, Relativistically invariant two-dimensional models of field theory which are integrable by means of the inverse scattering problem method, Sov. Phys.-JETP (Engl. Transl.) 47 (6) (1978). [8] A. A. Gelash, V. E. Zakharov, Superregular solitonic solutions: a novel scenario for the nonlinear stage of modulation instability, Nonlinearity 27 (4) (2014) R1.

  15. Nonlinear wave dynamics in self-consistent water channels

    Science.gov (United States)

    Pelinovsky, Efim; Didenkulova, Ira; Shurgalina, Ekaterina; Aseeva, Nataly

    2017-12-01

    We study long-wave dynamics in a self-consistent water channel of variable cross-section, taking into account the effects of weak nonlinearity and dispersion. The self-consistency of the water channel is considered within the linear shallow water theory, which implies that the channel depth and width are interrelated, so the wave propagates in such a channel without inner reflection from the bottom even if the water depth changes significantly. In the case of small-amplitude weakly dispersive waves, the reflection from the bottom is also small, which allows the use of a unidirectional approximation. A modified equation for Riemann waves is derived for the nondispersive case. The wave-breaking criterion (gradient catastrophe) for self-consistent channels is defined. If both weak nonlinearity and dispersion are accounted for, the variable-coefficient Korteweg–de Vries (KdV) equation for waves in self-consistent channels is derived. Note that this is the first time that a KdV equation has been derived for waves in strongly inhomogeneous media. Soliton transformation in a channel with an abrupt change in depth is also studied.

  16. Intimate partner violence in early adolescence: The role of gender ...

    African Journals Online (AJOL)

    Intimate partner violence in early adolescence: The role of gender, socioeconomic factors and the school. AJ Mason-Jones, P De Koker, SM Eggers, C Mathews, M Temmerman, E Leye, PJ de Vries, H de Vries ...

  17. Application of the method of lines for solving the KdV-Burger equation

    Directory of Open Access Journals (Sweden)

    rahma el sadat

    2017-12-01

    Full Text Available This paper presents two methods for obtaining the solutions to the nonlinear Korteweg-de Vries–Burgers (KdVB equation. The first is the method of lines (MOL. The second method is Adomian decomposition method (ADM. The numerical results of the MOL are compared with the analytical results of the ADM. In order to show the reliability of the considered methods we have compared the obtained solutions with the exact ones. The results reveal that the both methods are effective and convenient for solving such types of partial differential equations but the method of lines gives accurate results over the analytical method.

  18. Integrability: mathematical methods for studying solitary waves theory

    Science.gov (United States)

    Wazwaz, Abdul-Majid

    2014-03-01

    real features in a variety of vital areas in science, technology and engineering. In recognition of the importance of solitary waves theory and the underlying concept of integrable equations, a variety of powerful methods have been developed to carry out the required analysis. Examples of such methods which have been advanced are the inverse scattering method, the Hirota bilinear method, the simplified Hirota method, the Bäcklund transformation method, the Darboux transformation, the Pfaffian technique, the Painlevé analysis, the generalized symmetry method, the subsidiary ordinary differential equation method, the coupled amplitude-phase formulation, the sine-cosine method, the sech-tanh method, the mapping and deformation approach and many new other methods. The inverse scattering method, viewed as a nonlinear analogue of the Fourier transform method, is a powerful approach that demonstrates the existence of soliton solutions through intensive computations. At the center of the theory of integrable equations lies the bilinear forms and Hirota's direct method, which can be used to obtain soliton solutions by using exponentials. The Bäcklund transformation method is a useful invariant transformation that transforms one solution into another of a differential equation. The Darboux transformation method is a well known tool in the theory of integrable systems. It is believed that there is a connection between the Bäcklund transformation and the Darboux transformation, but it is as yet not known. Archetypes of integrable equations are the Korteweg-de Vries (KdV) equation, the modified KdV equation, the sine-Gordon equation, the Schrödinger equation, the Vakhnenko equation, the KdV6 equation, the Burgers equation, the fifth-order Lax equation and many others. These equations yield soliton solutions, multiple soliton solutions, breather solutions, quasi-periodic solutions, kink solutions, homo-clinic solutions and other solutions as well. The couplings of linear and

  19. New Indices of Endothelial Function Measured by Digital Thermal Monitoring of Vascular Reactivity: Data from 6084 Patients Registry

    Directory of Open Access Journals (Sweden)

    Morteza Naghavi

    2016-01-01

    Full Text Available Background. Endothelial function is viewed as a barometer of cardiovascular health and plays a central role in vascular reactivity. Several studies showed digital thermal monitoring (DTM as a simple noninvasive method to measure vascular reactivity that is correlated with atherosclerosis risk factors and coronary artery disease. Objectives. To further evaluate the relations between patient characteristics and DTM indices in a large patient registry. Methods. DTM measures were correlated with age, sex, heart rate, and systolic and diastolic blood pressure in 6084 patients from 18 clinics. Results. DTM vascular reactivity index (VRI was normally distributed and inversely correlated with age (r=-0.21, p<0.0001. Thirteen percent of VRI tests were categorized as poor vascular reactivity (VRI < 1.0, 70 percent as intermediate (1.0 ≤ VRI < 2.0, and 17 percent as good (VRI ≥ 2.0. Poor VRI (<1.0 was noted in 6% of <50 y, 10% of 50–70 y, and 18% of ≥70 y. In multiple linear regression analyses, age, sex, and diastolic blood pressure were significant but weak predictors of VRI. Conclusions. As the largest database of finger-based vascular reactivity measurement, this report adds to prior findings that VRI is a meaningful physiological marker and reflects a high level of residual risk found in patients currently under care.

  20. Peanut canopy temperature and NDVI response to varying irrigation rates

    Science.gov (United States)

    Variable rate irrigation (VRI) systems have the potential to conserve water by spatially allocating limited water resources. In this study, peanut was grown under a VRI system to evaluate the impact of differential irrigation rates on peanut yield. Additionally, we evaluated the impact of differenti...

  1. The functional variable method for solving the fractional Korteweg ...

    Indian Academy of Sciences (India)

    This paper presents the exact solutions for the fractional Korteweg–de Vries equations and the coupled Korteweg–de Vries equations with time-fractional derivatives using the functional variable method. The fractional derivatives are described in the modified Riemann–Liouville derivative sense. It is demonstrated that the ...

  2. The functional variable method for solving the fractional Korteweg ...

    Indian Academy of Sciences (India)

    Korteweg–de Vries equation; coupled Korteweg–de Vries equation; functional variable method. PACS Nos 02.30.Jr; 05.45.Yv. 1. Introduction. The physical and engineering processes have been modelled by means of fractional calculus, which are found to be best described by fractional differential equations. Unfor-.

  3. Irrigation management using an expert system, soil water potentials, and vegetative indices for spatial applications

    Science.gov (United States)

    Variable rate irrigation (VRI) systems are irrigation systems that are capable of applying different water depths both in the direction of travel and along the length of the irrigation system. However, when compared to traditional irrigation systems, VRI systems require a higher level of management...

  4. Nurse Administrators’ Perceptions of Power.

    Science.gov (United States)

    1989-01-01

    the power one individual has is relative to that of another individual. Zaleznik and Kets de Vries (1975) viewed power along with normal and... Zaleznik , A., & Kets de Vries, M. F. (1975). Power and the corporate mind. Boston: Houghton Mifflin. 92 Appendix A Cover Letter for Ouestionnaire 93

  5. Evaluation of potential water conservation using site-specific irrigation

    Science.gov (United States)

    With the advent of site-specific variable-rate irrigation (VRI) systems, irrigation can be spatially managed within sub-field-sized zones. Spatial irrigation management can optimize spatial water use efficiency and may conserve water. Spatial VRI systems are currently being managed by consultants ...

  6. Spectral Domain Optical Coherence Tomography in the Diagnosis and Management of Vitreoretinal Interface Pathologies

    Directory of Open Access Journals (Sweden)

    Yoreh Barak

    2012-01-01

    Full Text Available The introduction of spectral domain optical coherence tomography (SD-OCT has enhanced Vitreoretinal Interface (VRI imaging considerably and facilitated the diagnosis, followup, prognosis determination, and management of VRI-associated pathologies. HR-OCT became a common practical tool seen in almost every ophthalmology practice. Knowledge of SD-OCT image interpretation and recognition of pathologies are required for all ophthalmologists. This paper methodically reviews the normal aging process of the VRI and discusses several commonly encountered VRI pathologies. The role of SD-OCT imaging in VRI-associated disorders such as posterior vitreous detachment, vitreomacular traction syndrome, idiopathic epiretinal membranes, lamellar holes, pseudoholes, and full thickness macular holes is portrayed. Future perspectives of new OCT technologies based on SD-OCT are discussed.

  7. Clinical, biological, and microbiological pattern associated with ventriculostomy-related infection: a retrospective longitudinal study.

    Science.gov (United States)

    Mounier, Roman; Lobo, David; Cook, Fabrice; Fratani, Alexandre; Attias, Arie; Martin, Mathieu; Chedevergne, Karin; Bardon, Jean; Tazi, Sanaa; Nebbad, Biba; Bloc, Sébastien; Plaud, Benoît; Dhonneur, Gilles

    2015-12-01

    Our aim was to describe the pattern of ventriculostomy-related infection (VRI) development using a dynamic approach. Retrospective longitudinal study. We analyzed the files of 449 neurosurgical patients who underwent placement of external ventricular drain (EVD). During the study period, CSF sampling was performed on a daily base setting. VRI was defined as a positive CSF culture resulting in antibiotic treatment. For VRI patients, we arbitrary defined day 0 (D0) as the day antibiotic treatment was started. In these patients, we compared dynamic changes in clinical and biological parameters at four pre-determined time points: (D-4, D-3, D-2, D-1) with those of D0. For all CSF-positive cultures, we compared CSF biochemical markers' evolution pattern between VRI patients and the others, considered as a control cohort. Thirty-two suffered from VRI. Peripheral white blood cell count did not differ between D-4-D0. Median body temperature, CSF cell count, median Glasgow Coma Scale, CSF protein, and glucose concentrations were significantly different between D-4, D-3, D-2, and D0. At D0, 100 % of CSF samples yielded organisms in culture. The physician caring for the patient decided to treat VRI based upon positive CSF culture in only 28 % (9/32) of cases. In the control cohort, CSF markers' profile trends to normalize, while it worsens in the VRI patients. We showed that clinical symptoms and biological abnormalities of VRI evolved over time. Our data suggest that VRI decision to treat relies upon a bundle of evidence, including dynamic changes in CSF laboratory exams combined with microbiological analysis.

  8. Naar nieuwe vormen van kennis productie en -benutting

    NARCIS (Netherlands)

    Pieters, Jules; Voogt, Joke; McKenney, Susan; De Vries, Bregje; Westbroek, Hanna; Pareja Roblin, Natalie; Handelzalts, Adam; Walraven, Amber; Ormel, Bart

    2013-01-01

    Pieters, J., Voogt, J., McKenney, S., De Vries, B., Westbroek, H., Pareja Roblin, N., Handelzalts, A., Walraven, A., & Ormel, B. (2013). Naar nieuwe vormen van kennis productie en -benutting. Meso Magazine, 189, 25-26.

  9. Een onwrikbaar geloof in zijn gelijk. Sal Tas (1905–1976) Journalist van de wereld

    NARCIS (Netherlands)

    Van der Hoeven, Pien

    2017-01-01

    textabstractBook review of Tity de Vries. Een onwrikbaar geloof in zijn gelijk. Sal Tas (1905–1976) Journalist van de wereld. Aspekt, 2015, 465 pp. ISBN 9789461536792.DOI: 10.18146/2213-7653.2017.291

  10. Hollandi paviljon / Raivo Kotov

    Index Scriptorium Estoniae

    Kotov, Raivo

    2000-01-01

    Maailmanäituse EXPO 2000 Hollandi paviljonist Hannoveris. Arhitektid Winy Maas, Jacob van Rijs, Nathalie de Vries. Hollandi paviljon on näide looduse ja tehnika kooseksisteerimisest. Eesti paviljoni ehituse hetkeseis.

  11. "Kõike saab teha, miski ei näi enam imelik" / Triin Ojari

    Index Scriptorium Estoniae

    Ojari, Triin, 1974-

    2005-01-01

    Valgusinstallatsioonist Tallinnas Raekoja platsil 2005. aasta veebruaris. Hollandi arhitekt Winy Maas räägib 1991. aastal asutatud arhitektuuribüroo MVRDV tegevusest. Büroo asutajateks olid arhitektid Winy Maas, Jacob van Rijs ja Nathalie de Vries

  12. Browse Title Index

    African Journals Online (AJOL)

    Global challenges and local opportunities, Abstract. Susan Malcolm-Smith, Michelle Hoogenhout, Natalia Ing, Kevin GF Thomas, Petrus de Vries. Vol 22, No 2 (2010), Commentary Challenges in international collaboration in ...

  13. Role of biomedical knowledge in learning visual diagnosis

    NARCIS (Netherlands)

    Jarodzka, Halszka; Ledept, Annique; Boshuizen, Henny; Kirschner, Paul A.; De Vries, Hanneke

    2012-01-01

    Jarodzka, H., Ledept, A., Boshuizen, H. P. A., Kirschner, P. A., & De Vries, H. (2012, August). Role of biomedical knowledge in learning visual diagnosis. Poster presented at the EARLI SIG 14 'Learning and Professional Development', Antwerp, Belgium.

  14. Deconstructing the BRICs : Structural transformation and aggregate productivity growth

    NARCIS (Netherlands)

    de Vries, G.J.; Erumban, Abdul Azeez; Timmer, M.P.; Voskoboynikov, I.; Wu, H.X.

    de Vries, Gaaitzen J., Erumban, Abdul A., Timmer, Marcel P., Voskoboynikov, Ilya-Deconstructing the BRICs: Structural transformation and aggregate productivity growth This paper studies structural transformation and its implications for productivity growth in the BRIC countries (Brazil, Russia,

  15. Andestamine või kättemaks?

    Index Scriptorium Estoniae

    2013-01-01

    INSEAD'i juhtimisprofessori Manfred F. R. Kets de Vries' analüüsist "The Art of Forgiveness: Differentiating Transformational Leaders", mis tugineb Lõuna-Aafrika Vabariigi juhi Nelson Mandela ja Zimbabwe juhi Robert Mugabe näidetele

  16. VizieR Online Data Catalog: JHK' photometry of C stars in NGC 147 (Sohn+, 2006)

    Science.gov (United States)

    Sohn, Y. J.; Kang, A.; Rhee, J.; Shin, M.; Chun, M. S.; Kim, H. I.

    2005-09-01

    The equatorial coordinates, near-infrared photometric properties of 91 C stars, and color indices in VRI bands of cross-identified C stars with Nowotny et al. (2003, Cat. ) and Battinelli & Demers (2004, Cat. ). (1 data file).

  17. Disease: H01934 [KEGG MEDICUS

    Lifescience Database Archive (English)

    Full Text Available S, Malicdan MC, Boerkoel CF, Gahl WA, de Vries BB, van Haelst MM, Zenker M, Markello TC ... TITLE ... Recur...rent Mutations in the Basic Domain of TWIST2 Cause Ablepharon Macrostomia and Barbe

  18. Vibration Response Imaging: evaluation of rater agreement in healthy subjects and subjects with pneumonia

    Directory of Open Access Journals (Sweden)

    Makris Demosthenes

    2010-03-01

    Full Text Available Abstract Background We evaluated pulmonologists variability in the interpretation of Vibration response imaging (VRI obtained from healthy subjects and patients hospitalized for community acquired pneumonia. Methods The present is a prospective study conducted in a tertiary university hospital. Twenty healthy subjects and twenty three pneumonia cases were included in this study. Six pulmonologists blindly analyzed images of normal subjects and pneumonia cases and evaluated different aspects of VRI images related to the quality of data aquisition, synchronization of the progression of breath sound distribution and agreement between the maximal energy frame (MEF of VRI (which is the maximal geographical area of lung vibrations produced at maximal inspiration and chest radiography. For qualitative assessment of VRI images, the raters' evaluations were analyzed by degree of consistency and agreement. Results The average value for overall identical evaluations of twelve features of the VRI image evaluation, ranged from 87% to 95% per rater (94% to 97% in control cases and from 79% to 93% per rater in pneumonia cases. Inter-rater median (IQR agreement was 91% (82-96. The level of agreement according to VRI feature evaluated was in most cases over 80%; intra-class correlation (ICC obtained by using a model of subject/rater for the averaged features was overall 0.86 (0.92 in normal and 0.73 in pneumonia cases. Conclusions Our findings suggest good agreement in the interpretation of VRI data between different raters. In this respect, VRI might be helpful as a radiation free diagnostic tool for the management of pneumonia.

  19. Spectral Domain Optical Coherence Tomography in the Diagnosis and Management of Vitreoretinal Interface Pathologies

    OpenAIRE

    Barak, Yoreh; Ihnen, Mark A.; Schaal, Shlomit

    2012-01-01

    The introduction of spectral domain optical coherence tomography (SD-OCT) has enhanced Vitreoretinal Interface (VRI) imaging considerably and facilitated the diagnosis, followup, prognosis determination, and management of VRI-associated pathologies. HR-OCT became a common practical tool seen in almost every ophthalmology practice. Knowledge of SD-OCT image interpretation and recognition of pathologies are required for all ophthalmologists. This paper methodically reviews the normal aging proc...

  20. Targeting Destructive Narcissism: A New Approach for Identifying and Eliminating Toxic Senior Leaders in the U.S. Air Force

    Science.gov (United States)

    2014-02-13

    strong self-confidence and charisma . [12] [13] However, Kets deVries cautions that these leaders generate only a temporary sense of excitement that...Leadership: An Object Relations Perspective,” Human Relations, 38 (1985): 587. 23 Carolyn Morf and Fred Rhodewalt, “Unraveling the Paradoxes of Narcissism: A...facultyresearch/research/doc.cfm?did =13. Kets de Vries, Manfred F.R., and Danny Miller. “Narcissism and Leadership: An Object Relations Perspective

  1. Using quantitative breath sound measurements to predict lung function following resection

    Directory of Open Access Journals (Sweden)

    Keus Leendert

    2010-10-01

    Full Text Available Abstract Background Predicting postoperative lung function is important for estimating the risk of complications and long-term disability after pulmonary resection. We investigated the capability of vibration response imaging (VRI as an alternative to lung scintigraphy for prediction of postoperative lung function in patients with intrathoracic malignancies. Methods Eighty-five patients with intrathoracic malignancies, considered candidates for lung resection, were prospectively studied. The projected postoperative (ppo lung function was calculated using: perfusion scintigraphy, ventilation scintigraphy, and VRI. Two sets of assessments made: one for lobectomy and one for pneumonectomy. Clinical concordance was defined as both methods agreeing that either a patient was or was not a surgical candidate based on a ppoFEV1% and ppoDLCO% > 40%. Results Limits of agreement between scintigraphy and VRI for ppo following lobectomy were -16.47% to 15.08% (mean difference = -0.70%;95%CI = -2.51% to 1.12% and for pneumonectomy were -23.79% to 19.04% (mean difference = -2.38%;95%CI = -4.69% to -0.07%. Clinical concordance between VRI and scintigraphy was 73% for pneumonectomy and 98% for lobectomy. For patients who had surgery and postoperative lung function testing (n = 31, ppoFEV1% using scintigraphic methods correlated with measured postoperative values better than projections using VRI, (adjusted R2 = 0.32 scintigraphy; 0.20 VRI, however the difference between methods failed to reach statistical significance. Limits of agreement between measured FEV1% postoperatively and ppoFEV1% based on perfusion scintigraphy were -16.86% to 23.73% (mean difference = 3.44%;95%CI = -0.29% to 7.16%; based on VRI were -19.56% to 28.99% (mean difference = 4.72%;95%CI = 0.27% to 9.17%. Conclusions Further investigation of VRI as an alternative to lung scintigraphy for prediction of postoperative lung function is warranted.

  2. New conformity indices based on the calculation of distances between the target volume and the volume of reference isodose

    Science.gov (United States)

    Park, J M; Park, S-Y; Ye, S-J; Kim, J H; Carlson, J

    2014-01-01

    Objective: To present conformity indices (CIs) based on the distance differences between the target volume (TV) and the volume of reference isodose (VRI). Methods: The points on the three-dimensional surfaces of the TV and the VRI were generated. Then, the averaged distances between the points on the TV and the VRI were calculated (CIdistance). The performance of the presented CIs were evaluated by analysing six situations, which were a perfect match, an expansion and a reduction of the distance from the centroid to the VRI compared with the distance from the centroid to the TV by 10%, a lateral shift of the VRI by 3 cm, a rotation of the VRI by 45° and a spherical-shaped VRI having the same volume as the TV. The presented CIs were applied to the clinical prostate and head and neck (H&N) plans. Results: For the perfect match, CIdistance was 0 with 0 as the standard deviation (SD). When expanding and reducing, CIdistance was 10 and −10 with SDs 11. The average value of the CIdistance in the prostate and H&N plans was 0.13 ± 7.44 and 6.04 ± 23.27, respectively. Conclusion: The performance of the CIdistance was equal or better than those of the conventional CIs. Advances in knowledge: The evaluation of target conformity by the distances between the surface of the TV and the VRI could be more accurate than evaluation with volume information. PMID:25225915

  3. Modification of Plasma Solitons by Resonant Particles

    DEFF Research Database (Denmark)

    Karpman, Vladimir; Lynov, Jens-Peter; Michelsen, Poul

    1980-01-01

    A consistent theory of plasma soliton interaction with resonant particles is developed. A simple derivation of a perturbed Korteweg–de Vries equation with the interaction term is presented. It is shown how the known limit cases (such as Ott–Sudan’s, etc.) can be derived from the general equations...... Korteweg–de Vries equation. Laboratory measurements carried out in a strongly magnetized, plasma‐filled waveguide and results from particle simulation are interpreted in terms of the analytical results....

  4. VRILLE Controls PDF Neuropeptide Accumulation and Arborization Rhythms in Small Ventrolateral Neurons to Drive Rhythmic Behavior in Drosophila.

    Science.gov (United States)

    Gunawardhana, Kushan L; Hardin, Paul E

    2017-11-20

    In Drosophila, the circadian clock is comprised of transcriptional feedback loops that control rhythmic gene expression responsible for daily rhythms in physiology, metabolism, and behavior. The core feedback loop, which employs CLOCK-CYCLE (CLK-CYC) activators and PERIOD-TIMELESS (PER-TIM) repressors to drive rhythmic transcription peaking at dusk, is required for circadian timekeeping and overt behavioral rhythms. CLK-CYC also activates an interlocked feedback loop, which uses the PAR DOMAIN PROTEIN 1ε (PDP1ε) activator and the VRILLE (VRI) repressor to drive rhythmic transcription peaking at dawn. Although Pdp1ε mutants disrupt activity rhythms without eliminating clock function, whether vri is required for clock function and/or output is not known. Using a conditionally inactivatable transgene to rescue vri developmental lethality, we show that clock function persists after vri inactivation but that activity rhythms are abolished. The inactivation of vri disrupts multiple output pathways thought to be important for activity rhythms, including PDF accumulation and arborization rhythms in the small ventrolateral neuron (sLN v ) dorsal projection. These results demonstrate that vri acts as a key regulator of clock output and suggest that the primary function of the interlocked feedback loop in Drosophila is to drive rhythmic transcription required for overt rhythms. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. KAYAK-α modulates circadian transcriptional feedback loops in Drosophila pacemaker neurons.

    Science.gov (United States)

    Ling, Jinli; Dubruille, Raphaëlle; Emery, Patrick

    2012-11-21

    Circadian rhythms are generated by well-conserved interlocked transcriptional feedback loops in animals. In Drosophila, the dimeric transcription factor CLOCK/CYCLE (CLK/CYC) promotes period (per), timeless (tim), vrille (vri), and PAR-domain protein 1 (Pdp1) transcription. PER and TIM negatively feed back on CLK/CYC transcriptional activity, whereas VRI and PDP1 negatively and positively regulate Clk transcription, respectively. Here, we show that the α isoform of the Drosophila FOS homolog KAYAK (KAY) is required for normal circadian behavior. KAY-α downregulation in circadian pacemaker neurons increases period length by 1.5 h. This behavioral phenotype is correlated with decreased expression of several circadian proteins. The strongest effects are on CLK and the neuropeptide PIGMENT DISPERSING FACTOR, which are both under VRI and PDP1 control. Consistently, KAY-α can bind to VRI and inhibit its interaction with the Clk promoter. Interestingly, KAY-α can also repress CLK activity. Hence, in flies with low KAY-α levels, CLK derepression would partially compensate for increased VRI repression, thus attenuating the consequences of KAY-α downregulation on CLK targets. We propose that the double role of KAY-α in the two transcriptional loops controlling Drosophila circadian behavior brings precision and stability to their oscillations.

  6. Mechanisms underlying hemodynamic and neuroendocrine stress reactivity at different phases of the menstrual cycle.

    Science.gov (United States)

    Gordon, Jennifer L; Girdler, Susan S

    2014-04-01

    This study examined the association of menstrual cycle phase with stress reactivity as well as the hormonal and neuroendocrine mechanisms contributing to cycle effects. Fifty-seven women underwent a modified Trier Social Stress Test during the early follicular, late follicular, and luteal phases of the menstrual cycle. Greater increases in cardiac index (CI) and greater decreases in vascular resistance index (VRI) during speech were observed in the luteal phase relative to other phases, while greater increases in epinephrine (EPI) was observed during the late follicular and luteal phases compared to the early follicular phase. Luteal phase estradiol predicted luteal EPI reactivity but not CI or VRI reactivity, while luteal phase EPI reactivity predicted luteal phase CI and VRI reactivity. Thus, cycle-related changes in EPI reactivity may be a stronger determinant of cycle effects on hemodynamic reactivity than sex hormones per se. Copyright © 2014 Society for Psychophysiological Research.

  7. The Painlevé Handbook

    CERN Document Server

    Conte, Robert

    2008-01-01

    Nonlinear differential or difference equations are encountered not only in mathematics, but also in many areas of physics (evolution equations, propagation of a signal in an optical fiber), chemistry (reaction-diffusion systems), and biology (competition of species). This book introduces the reader to methods allowing one to build explicit solutions to these equations. A prerequisite task is to investigate whether the chances of success are high or low, and this can be achieved without any a priori knowledge of the solutions, with a powerful algorithm presented in detail called the Painlevé test. If the equation under study passes the Painlevé test, the equation is presumed integrable. If on the contrary the test fails, the system is nonintegrable or even chaotic, but it may still be possible to find solutions. The examples chosen to illustrate these methods are mostly taken from physics. These include on the integrable side the nonlinear Schrödinger equation (continuous and discrete), the Korteweg-de Vrie...

  8. ENVIRONMENTAL REVIEWS AND CASE STUDIES: The National Park Service Visual Resource Inventory: Capturing the Historic and Cultural Values of Scenic Views

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, Robert G.; Meyer, Mark E.

    2016-08-30

    Several United States (US) federal agencies have developed visual resource inventory (VRI) and management systems that reflect specific agency missions and visual resource management objectives. These programs have varied in the degree to which they incorporate historic and cultural elements and values into the scenic inventory process. The recent nationwide expansion of renewable energy and associated transmission development is causing an increase in visual impacts on both scenic and historic/cultural resources. This increase has highlighted the need for better integration of visual and historic/cultural resource assessment and management activities for land use planning purposes. The US Department of the Interior National Park Service (NPS), in response to concerns arising from potential scenic impacts from renewable energy, electric transmission, and other types of development on lands and waters near NPS units, has developed a VRI process for high-value views both within and outside NPS unit boundaries. The NPS VRI incorporates historic and cultural elements and values into the scenic resource inventory process and provides practical guidance and metrics for successfully integrating historic and cultural concerns into the NPS’s scenic resource conservation efforts. This article describes the NPS VRI process and compares it with the VRI processes of the US Department of the Interior Bureau of Land Management and the US Department of Agriculture Forest Service, with respect to the incorporation of historic and cultural values. The article discusses why a scenic inventory approach that more robustly integrates the historic and cultural values of the landscape is essential for NPS landscapes, and for fulfillment of NPS’s mission. Inventories are underway at many NPS units, and the results indicate that the VRI process can be used successfully to capture important historic and cultural resource information and incorporate that information into the assessment

  9. Intimate partner violence in early adolescence: The role of gender ...

    African Journals Online (AJOL)

    Intimate partner violence in early adolescence: The role of gender, socioeconomic factors and the school. A J Mason-Jones,1,2 PhD, MPH, MSc, RGN, RHV; P De Koker,2,3 MA; S M Eggers,4 MSc; C Mathews,5,2 PhD;. M Temmerman,3,6 MB ChB, PhD; E Leye,3 PhD; P J de Vries,2 MB ChB, MRCPsych, PhD; H de Vries,4 ...

  10. An Efficient Numerical Approach for Solving Nonlinear Coupled Hyperbolic Partial Differential Equations with Nonlocal Conditions

    Directory of Open Access Journals (Sweden)

    A. H. Bhrawy

    2014-01-01

    Full Text Available One of the most important advantages of collocation method is the possibility of dealing with nonlinear partial differential equations (PDEs as well as PDEs with variable coefficients. A numerical solution based on a Jacobi collocation method is extended to solve nonlinear coupled hyperbolic PDEs with variable coefficients subject to initial-boundary nonlocal conservation conditions. This approach, based on Jacobi polynomials and Gauss-Lobatto quadrature integration, reduces solving the nonlinear coupled hyperbolic PDEs with variable coefficients to a system of nonlinear ordinary differential equation which is far easier to solve. In fact, we deal with initial-boundary coupled hyperbolic PDEs with variable coefficients as well as initial-nonlocal conditions. Using triangular, soliton, and exponential-triangular solutions as exact solutions, the obtained results show that the proposed numerical algorithm is efficient and very accurate.

  11. Exact Traveling Wave Solutions for Wick-Type Stochastic Schamel KdV Equation

    Directory of Open Access Journals (Sweden)

    Hossam A. Ghany

    2014-01-01

    Full Text Available F-expansion method is proposed to seek exact solutions of nonlinear partial differential equations. By means of Hermite transform, inverse Hermite transform, and white noise analysis, the variable coefficients and Wick-type stochastic Schamel KdV equations are completely described. Abundant exact traveling wave solutions for variable coefficients Schamel KdV equations are given. These solutions include exact stochastic Jacobi elliptic functions, trigonometric functions, and hyperbolic functions solutions.

  12. AN INEQUALITY BETWEEN THE WEIGHTED AVERAGE AND THE ROWWISE CORRELATION-COEFFICIENT FOR PROXIMITY MATRICES

    NARCIS (Netherlands)

    KRIJNEN, WP

    De Vries (1993) discusses Pearson's product-moment correlation, Spearman's rank correlation, and Kendall's rank-correlation coefficient for assessing the association between the rows of two proximity matrices. For each of these he introduces a weighted average variant and a rowwise variant. In this

  13. Die implikasies van artikel 2 (1 (a van die wet op die nasionale onderwysbeleid, 1967

    Directory of Open Access Journals (Sweden)

    J. Bekker

    1969-03-01

    Full Text Available Op 31 Maart 1967 is die veelbesproke Wet op die Nasionale Onderwysbeleid, 1967 gepromulgeer. Daar is ’n raamwerk van tien beginsels neergelê wat onder meer handel oor sake soos Christelike karakter, nasionale karakter, moedertaalonderwys, die plek van die ouergemeenskap, vry onderwys, koordinasie op nasionale grondslag van leerplanne en kursusse, ens.

  14. Res Dec 07 Final 05-12-07

    Indian Academy of Sciences (India)

    client1

    2007-12-05

    Dec 5, 2007 ... melting point and freezing point, called Thermal Hysteresis (TH), is a measure of the antifreeze activity. This mechanism is also known as freeze avoidance. According to the adsorption inhibi- tion mechanism proposed by Raymond and DeVries, irreversible adsorption of AFPs on the ice crystal surface ...

  15. Nonlinear stability of pulsational mode of gravitational collapse in ...

    Indian Academy of Sciences (India)

    reductive perturbation technique, a Korteweg–de Vries (KdV) equation for investigating the nonlinear evolution of the ... in the presence of partially ionized grains in a self-gravitating dusty plasma system, is similarly ... be justified under the consideration of radial symmetry assuming that the wavelength of fluctuation is much ...

  16. Building Eclectic Personal Learning Landscapes with Open Source Tools

    NARCIS (Netherlands)

    Kalz, Marco

    2008-01-01

    Kalz, M. (2005). Building Eclectic Personal Learning Landscapes with Open Source Tools. In F. de Vries, G. Attwell, R. Elferink & A. Tödt (Eds.), Open Source for Education in Europe. Research & Practice (= Proceedings of the Open Source for Education in Europe Conference) (pp. 163-168). 2005,

  17. Diba et al., Afr. J. Infect. Dis. (2014) 8(1): 1 – 4 .11i8v.ajid/ .4314 10 ...

    African Journals Online (AJOL)

    cadewumi

    availability and high sensitivity of diagnosis, PCR-RFLP using single restriction enzyme was studied in this study for the identification of. Aspergillus species isolated from the .... Verweij, P. E., Te Dorsthorst, D. T. A., Rijs, A. J. M. M., De Vries-Hospers, H. G. and Meis, J. F. G. M. (2002). Nationwide survey of In vitro activities of ...

  18. The nucleotide sequence of the variable region in Trypanosoma brucei completes the sequence analysis of the maxicircle component of mitochondrial kinetoplast DNA

    NARCIS (Netherlands)

    Sloof, P.; de Haan, A.; Eier, W.; van Iersel, M.; Boel, E.; van Steeg, H.; Benne, R.

    1992-01-01

    The nucleotide sequence of two non-contiguous DNA fragments of 4.0 and 2.2 kb, respectively, of the kinetoplast maxicircle of Trypanosoma brucei brucei EATRO strain 427 has been determined, completing the sequence analysis of the so-called variable region (see also de Vries et al., 1988, Mol.

  19. The new green revolution

    NARCIS (Netherlands)

    Fresco, Louise O.

    2015-01-01

    By combining scientific excellence with social involvement, M. S. Swaminathan has put himself in the tradition of the great agricultural researchers such as Von Liebich, Vavilov, De Vries, Haber and his friend and colleague Norman Borlaug that have defeated the Spectre of Malthus. His ability to

  20. "The colorful trash of the Flemish School": Netherlandish art and Russian literature

    NARCIS (Netherlands)

    Weststeijn, T.; de Haard, E.; Honselaar, W.; Stelleman, J.

    2008-01-01

    Willem Weststeijn once began an essay with a thought experiment: what would have happened when the Netherlands had become a Socialist state, with a literary canon championing Theun de Vries as the nation’s prime author? In the realm of the visual arts, there is no need for this kind of speculation.

  1. Time-dependent excitation and ionization modelling of absorption-line variability due to GRB080310

    DEFF Research Database (Denmark)

    Vreeswijk, P.M.; De Cia, A.; Jakobsson, P.

    2013-01-01

    .42743. To estimate the rest-frame afterglow brightness as a function of time, we use a combination of the optical VRI photometry obtained by the RAPTOR-T telescope array, which is presented in this paper, and Swift's X-Ray Telescope (XRT) observations. Excitation alone, which has been successfully applied...

  2. Tiger Nut

    African Journals Online (AJOL)

    Tiger Nut and Health, 2013). Chufa tubers can be used for the production of alcohol by fermentation (Des-Vries, 1991). Roasted tubers are used as a coffee substitute (Oderinde and Tahir, 1988). The oil of tiger nut (C. esculentus) is used for the.

  3. Mobiele apparaten en apps als versnellers van Open Educational Resources

    NARCIS (Netherlands)

    De Vries, Fred; Thuss, Frank

    2013-01-01

    De Vries, F., & Thuss, F. (2013). Mobiele apparaten en apps als versnellers van Open Educational Resources? In R. Jacobi, H. Jelgerhuis, & N. van der Woert (Eds.), Trendrapport Open Educational Resources 2013 (pp. 51-54). Utrecht: SURF Foundation - Special Interest Group Open Educational Resources

  4. Mobile Devices and Apps as Accelerators for OER

    NARCIS (Netherlands)

    De Vries, Fred; Thuss, Frank

    2013-01-01

    De Vries, F., & Thuss, F. (2013). Mobile Devices and Apps as accelerators for OER. In R. Jacobi, H. Jelgerhuis, & N. Van der Woert (Eds.), Trendreport Open Educational Resources 2013 (pp. 49-52). Utrecht: SURF Foundation - Special Interest Group Open Educational Resources SURF.

  5. ORIGINAL PAPER ORIG ORIG Percutaneous stone removal

    African Journals Online (AJOL)

    The percutaneous tract was made by the interven- tional radiologist under ultrasound combined with. Percutaneous stone removal. M N van der Ness, MB ChB, DA (SA),. DRCOG (UK). C S de Vries, MB ChB, MMed (Rad). Department of Diagnostic Radiology, Universitas Hospital, University of the Free State, Bloemfontein.

  6. Optimization of enantioselective production of chiral epichlorohydrin ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-10-19

    Oct 19, 2009 ... Kinetic resolution for optically active epoxides by microbial enantioselective hydrolysis. Biotechnol. Tech. 12: 225-228. Choi WJ, Lee EY, Yoon SJ, Yang ST, Choi CY (1999). Biocatalytic production of chiral epichlorohydrin in organic solvents. J. Biosci. Bioeng. 88: 339-341. De Vries EJ, Janssen DB (2003).

  7. SER-Commissie neemt roer Arboraad over: afscheid met gemengde gevoelens

    NARCIS (Netherlands)

    Blijswijk, M. van

    1993-01-01

    De Arboraad heeft haar laatste vergadering achter de rug. De Raad wordt geïntegreerd in de SER door middel van een nieuwe SER-commissie Arbeidsomstandigheden. Hoewel de oud-voorzitter van de Arboraad pleitte voor een voorlopig nog zelfstandig functionerende Raad, wil minister De Vries door middel

  8. Enterococcal endocarditis - a case treated with teicoplanin and ...

    African Journals Online (AJOL)

    Enterococcal endocarditis - a case treated with teicoplanin and amoxycillin. P L Botha, M C Struwig, W de Vries, J Hough, L J Chalkley. Abstract. The study aimed to determine the antibacterial therapy effective in the cure of endocarditis caused by Enterococcus faecalis resistant to clinically achievable levels of vancomycin.

  9. Ion-acoustic solitons in multispecies spatially inhomogeneous ...

    Indian Academy of Sciences (India)

    Abstract. Ion-acoustic solitons are investigated in the spatially inhomogeneous plasma having electrons–positrons and ions. The soliton characteristics are described by. Korteweg–de Vries equation which has an additional term. The density and temperature of different species play an important role for the amplitude and ...

  10. Pseudoglessula Libera, a new Subulinid land snail from Guinea, West Africa (Mollusca, Gastropoda Pulmonata)

    NARCIS (Netherlands)

    Solem, A.; Bruggen, van A.C.

    1976-01-01

    Study of some land snails collected in Guinea, West Africa, by Ms. Diane deVry has led to the description of a new species, Pseudoglessula libera. It is currently known only from several localities near Conakry, but probably has a wide distribution. Detailed comparisons with previously described

  11. B Talukdar

    Indian Academy of Sciences (India)

    Home; Journals; Pramana – Journal of Physics. B Talukdar. Articles written in Pramana – Journal of Physics. Volume 58 Issue 3 March 2002 pp 443-448 Research Articles. Korteweg–de Vries hierarchy using the method of base equations · Subhendu Chakrabarti J Pal B Talukdar · More Details Abstract Fulltext PDF.

  12. Matrix factorization method for the Hamiltonian structure of ...

    Indian Academy of Sciences (India)

    S Ghosh, B Talukdar and S Chakraborti. The Hamiltonian structure of non-linear evolution equations solvable by the inverse spectral method was discovered in 1971 by Zakharov and Faddeev [2] and by Gardner [3] who interpreted the Kortweg-de Vries (KdV) equation as a completely integrable Hamilto- nian system in an ...

  13. Mäss põhjusega : kortermaja Silodamil Amsterdamis / Klaske Havik

    Index Scriptorium Estoniae

    Havik, Klaske, 1975-

    2002-01-01

    Büroo MVRDV suurim elamuprojekt. Arhitektid Winy Maas, Jacob van Rijs, Nathalie de Vries, kaasa töötasid Frans de Witte, Willem Timmer, Eline Strijkers, Bernd Felsinger, Duzan Koepel. Viis võistlustöö kaasautorit. Hoone paikneb kai tipus, on ehitatud vette postide peale. Ill.: 7 plaani, 11 vaadet

  14. No increased susceptibility to breast cancer from combined CHEK2 1100delC genotype and the HLA class III region risk factors

    NARCIS (Netherlands)

    de Jong, Mirjam; Nolte, Ilja; te Meerman, Gerhardus; van der Graaf, WTA; Oosterom, E; Bruinenberg, M; van der Steege, G; Oosterwijk, JC; van der Hout, Annemarie; Boezen, HM; Schaapveld, M; Kleibeuker, JH; de Vries, EGE

    CHEK2 is low-penetrance breast cancer susceptibility gene. The 1100delC mutation may interact with variants/mutations in other breast cancer susceptibility loci. We identified a risk haplotype in the HLA class III region in breast cancer patients [de Jong MM, Nolte IM, de Vries EGE, et al. The HLA

  15. Arabidopsis RecQ14A suppresses homologous recombination and modulates DNA damage responses

    NARCIS (Netherlands)

    Bagherieh-Najjar, M.B.; De Vries, O.H.M.; Hille, J.; Dijkwel, P.P.

    2005-01-01

    Arabidopsis RecQl4A suppresses homologous recombination and modulates DNA damage responses Authors: Bagherieh-Najjar, Mohammad B.; Vries, Onno M.H.; Hille, Jacques; Dijkwel, Paul P. Source: The Plant Journal, Volume 43, Number 6, September 2005 , pp. 789-798(10) Publisher: Blackwell Publishing

  16. Measurement in health psychology: combining theory, qualitative, and quantitative methods to do it right : 6th Methods in Health Psychology Symposium

    NARCIS (Netherlands)

    Peters, G.-J.Y; Dima, A.; Plass, A.M.; Crutzen, R.; Gibbons, C.; Doyle, F.

    2016-01-01

    A recent debate in Health Psychology Review demonstrated the importance of careful attention to measurement and operationalisation of health psychology constructs (Beauchamp, 2016; Brewer, 2016; de Vries, 2016; Schwarzer & McAuley, 2016; Williams & Rhodes, 2016a, 2016b). This need is met by rapid

  17. Die Diepte-ondersoek

    African Journals Online (AJOL)

    21 Aug 1971 ... Daarbenewens is die algemene lewensduurte ook verantwoordelik vir 'n stygende kostepatroon in die geneeskunde. 'n. Dekade of twee, drie gelede kon ons nog redelik verwag dat iedere pasient sy eie potjie moes krap, met die uitsondering van die werklik armes wat vry mediese dienste moes ontvang.

  18. Download this PDF file

    African Journals Online (AJOL)

    153159. SURGICAL CHALLENGES IN LYMPHATIC FILARIASIS. C. R. DE VRIES. University of Utah, Salt Lake City, Utah, USA. INTRODUCTION. For more than 43 million Africans infected with the Wuchereri'a bancrofti, the risk of de- veloping lymphedema of the limbs and genita- lia, hydroceles, and chyluria is significant.

  19. Pramana – Journal of Physics | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    ... dispersion-managed optical communication system and mode-locked fibre lasers. pp 581-597 Regular. Nonlinear structures for extended Korteweg–de Vries equation in multicomponent plasma · Abdelsalam U M Allehiany F M Moslem W M El-Labany S K · More Details Abstract Fulltext PDF. Using the fluid hydrodynamic ...

  20. Controlling Agglomeration of Protein Aggregates for Structure Formation in Liquid Oil

    NARCIS (Netherlands)

    Vries, De Auke; Lopez Gomez, Yuly; Jansen, Bas; Linden, van der Erik; Scholten, Elke

    2017-01-01

    Proteins are known to be effective building blocks when it comes to structure formation in aqueous environments. Recently, we have shown that submicron colloidal protein particles can also be used to provide structure to liquid oil and form so-called oleogels (de Vries, A. J. Colloid Interface

  1. Hubble Space Telescope and VLA observations of two optical continuum knots in the jet of 3C 380

    NARCIS (Netherlands)

    O'Dea, CP; De Vries, W; Biretta, JA; Baum, SA

    We present Nubble Space Telescope Wide Field Planetary Camera 2 broadband red and linear ramp filter (isolating redshifted [O II] lambda 3727) observations and subarcsecond-resolution 15, 22, and 43 GHz VLA observations of the radio-loud quasar 3C 380. We confirm the report of de Vries et ai. that

  2. A century of genetics

    Science.gov (United States)

    Daniel J. Fairbanks

    2001-01-01

    In 1866, Gregor Mendel published his experiments on heredity in the garden pea (Pisum sativum). The fundamental principles of inheritance derived from his work apply to nearly all eukaryotic species and are now known as Mendelian principles. Since 1900, Mendel has been recognized as the founder of genetics. In 1900, three botanists, Carl Correns, Hugo De Vries, and...

  3. Majad moodsalt tänavalt / Tiina Tammet

    Index Scriptorium Estoniae

    Tammet, Tiina, 1971-

    2001-01-01

    1927. a. Stuttgarti ehitatud Weissenhofi elamugrupist (Le Corbusier, P. Jeanneret, J. J. P. Oud, M. Stam, W. Gropius, P. Behrens, M. ja B. Taut jt.) ja 1933. a. valminud Vaarika-Maasika t. asumist (A. Volberg, E. J. Kuusik, E. Jacoby, E. Lohk, F. de Vries). Näitus "Moodsad näidisasumid: Weissenhof & Maasika-Vaarika" Rotermanni soolalaos.

  4. Predicators of Success for Undergraduate Students Reinstated after an Academic Dismissal at a Small Midwest Private University Campus

    Science.gov (United States)

    Meador, Ryan E.

    2012-01-01

    This study examined students who successfully applied for reinstatement after being academically dismissed for the first time in order to discover indicators of future success. This study examined 666 students' appeals filed at the DeVry University Kansas City campus between 2004 and 2009. Binary logistic regression was used to discover if a…

  5. Validation of Tip Corrections for Wind Turbine computations

    DEFF Research Database (Denmark)

    Shen, Wen Zhong; Mikkelsen, Robert; Sørensen, Jens Nørkær

    2003-01-01

    Tip loss effect of rotors plays an important role in predictions of wind turbine performance. Classical tip corrections, based on the Prandtl tip reduction function, including Glauert´, Wilson & Lissaman´s and De Vries´ corrections are considered in the paper. In the proximity of the tip...

  6. Contrast-enhanced computed tomography angiography and volume-rendered imaging for evaluation of cellophane banding in a dog with extrahepatic portosystemic shunt

    Directory of Open Access Journals (Sweden)

    H. Yoon

    2011-04-01

    Full Text Available A 4-year-old, 1.8 kg, male, castrated Maltese was presented for evaluation of urolithiasis. Urinary calculi were composed of ammonium biurate. Preprandial and postprandial bile acids were 44.2 and 187.3 μmol/ , respectively (reference ranges 0–10 and 0–20 μmol/ , respectively. Single-phase contrast-enhanced computed tomography angiography (CTA with volume-rendered imaging (VRI was obtained. VRI revealed a portocaval shunt originating just cranial to a tributary of the gastroduodenal vein and draining into the caudal vena cava at the level of the epiploic foramen. CTA revealed a 3.66 mm-diameter shunt measured at the level of the termination of the shunt and a 3.79 mm-diameter portal vein measured at the level between the origin of the shunt and the porta of the liver. Surgery was performed using cellophane banding without attenuation. Follow-up single-phase CTA with VRI was obtained 10 weeks after surgery. VRI revealed no evidence of portosystemic communication on the level of a cellophane band and caudal to the cellophane band. CTA demonstrated an increased portal vein diameter (3.79–5.27 mm measured at the level between the origin of the shunt and the porta of the liver. Preprandial and postprandial bile acids were 25 and 12.5 μmol/ , respectively (aforementioned respective reference ranges, 3 months post-surgery. No problems were evident at 6 months.

  7. Die onderwysmanifes oor waardes en demokrasie in die onderwys ...

    African Journals Online (AJOL)

    Erna Kinsey

    28 Aug 2001 ... In die verband stel John Locke dit dat die mens 'n reg het op lewe, vry- heid, gesondheid, en besittings en dat ander hierdie regte moet respek- teer. As ons aanvaar dat sekere regte met menswees gegee is, dan vloei dit voort dat sodanige regte. • natuurlik is (met menswees gegee) in sover as wat hulle ...

  8. Propagation characteristics of ion-acoustic double layer in ...

    Indian Academy of Sciences (India)

    Harvinder Kaur

    2017-07-24

    Jul 24, 2017 ... Abstract. In the present investigation, ion-acoustic double layers in an inhomogeneous plasma consisting of. Maxwellian and non-thermal distributions of electrons are studied. We have derived a modified Korteweg–de Vries. (mKdV) equation for ion-acoustic double layers propagating in a collisionless ...

  9. Download this PDF file

    African Journals Online (AJOL)

    user

    hand critical of the Grimms' approach (Reichmann 2012: 206). Reichmann lists some excellent etymological dictionaries, among which the Dutch Etymologisch. Woordenboek van het Nederlands (Et. Wb. Ned. (2003)), of which three volumes have so far appeared, as well as that by J. de Vries (1997) and that by P.A.F. van.

  10. The Reception of Hugo de Vries’s Intracellular Pangenesis; the Discussion with August Weismann

    NARCIS (Netherlands)

    Stamhuis, I.H.

    2003-01-01

    In 1889 Hugo de Vries published Intracellular Pangenesis in which he formulated his ideas on heredity. The high expectations of the impression these ideas would make did not come true and publication was negated or reviewed critically. From the reactions of his Dutch colleagues and the discussion

  11. Application and comparison of four selected procedures for the isolation of cell-wall material from the skin of grapes cv. Monastrell

    Energy Technology Data Exchange (ETDEWEB)

    Apolinar-Valiente, R., E-mail: tokay04@hotmail.com [Departamento de Tecnologia de Alimentos, Nutricion y Bromatologia, Facultad de Veterinaria, Universidad de Murcia, Campus de Espinardo, 30100 Murcia (Spain); Romero-Cascales, I., E-mail: miromero@um.es [Departamento de Tecnologia de Alimentos, Nutricion y Bromatologia, Facultad de Veterinaria, Universidad de Murcia, Campus de Espinardo, 30100 Murcia (Spain); Lopez-Roca, J.M., E-mail: jmlroca@um.es [Departamento de Tecnologia de Alimentos, Nutricion y Bromatologia, Facultad de Veterinaria, Universidad de Murcia, Campus de Espinardo, 30100 Murcia (Spain); Gomez-Plaza, E., E-mail: encarnag@um.es [Departamento de Tecnologia de Alimentos, Nutricion y Bromatologia, Facultad de Veterinaria, Universidad de Murcia, Campus de Espinardo, 30100 Murcia (Spain); Ros-Garcia, J.M., E-mail: jmros@um.es [Departamento de Tecnologia de Alimentos, Nutricion y Bromatologia, Facultad de Veterinaria, Universidad de Murcia, Campus de Espinardo, 30100 Murcia (Spain)

    2010-02-15

    In order to choose an appropriate cell-wall material (CWM) isolation procedure in grapes cv. Monastrell, four different standard procedures have been tested, and a comparison made of the amount of cell-wall material obtained, its composition and morphology. The CWM was isolated as the 70% ethanol insoluble residue (de Vries method), as the absolute ethanol insoluble residue filtered sequentially through nylon mesh (Nunan method), as the insoluble residue in sodium deoxycholate-phenol-acetic acid-water (Selvendran method) and as the N-[2-hydroxyethyl]-piperazine-N'-2-ethanesulfonic acid (HEPES) insoluble residue (Vidal method). All extractions were done in triplicate and the efficiency of the extractive procedure established. Carbohydrates, proteins, and phenolic compounds were analysed, as the main constituents of CWM. The morphology of the isolated CWM was visualized by scanning electron microscopy (SEM). The Selvendran method had the highest efficiency, while the Nunan method had the lower one. Regarding the carbohydrates composition, the four different CWM were rich in uronic acids and glucose, together with varying amounts of arabinose, xylose, mannose and galactose. The Selvendran method had the lower value of total carbohydrates and the CWM shows more plasmatic membrane impurities in SEM images. The chemical results of the Vidal and de Vries methods were quite similar, but the Vidal method was more time consuming than the de Vries method. According to the results, the de Vries method was chosen to produce a representative cell-wall material fraction from Monastrell grapes skin.

  12. They're All Business.

    Science.gov (United States)

    Nicklin, Julie L.

    1995-01-01

    DeVry Inc., one of the nation's largest for-profit postsecondary education systems, has been aggressive and successful, expanding to 13 technical institutes in the United States and Canada. The company specializes in providing high-school graduates seeking technical jobs and older workers needing additional training with no-frills, skills-based…

  13. New exact solutions to the generalized KdV equation with ...

    Indian Academy of Sciences (India)

    Abstract. In this paper, by using a transformation and an application of Fan subequation, we study a class of generalized Korteweg–de Vries (KdV) equation with generalized evolution. As a result, more types of exact solutions to the generalized KdV equation with generalized evolution are obtained, which include more ...

  14. Evolution: Yesterday, Today, Tomorrow

    Science.gov (United States)

    Mayer, William V.

    1977-01-01

    The author reviews research on the origins of life, beginning with Thales (636 B.C.), synthesized by C. Darwin in "The Origin of Species," continued by H. DeVries' mutation theory, and enhanced by the discovery in 1944 of DNA. For journal availability, see SO 505 260. (AV)

  15. The Development of an Instrument to Measure the Theoretical Parameters of Charisma within Organizations

    Science.gov (United States)

    1991-09-01

    Burns (1978)/Bass (1985) .............. . Katz and Kahn (1973) ........ ................ 28 House (1977) .......................... 30 Zaleznik and...degree, been unsuccessful in predicting performance. There are those (notably Mintzberg (1973, 1982) and Zaleznik (1977)) who feel this downfall is...existing in organizations. He discusses three types: traditional, legal, and charismatic" ( Zaleznik and Kets De Vries, 1975:13). Each of these authority

  16. Charisma and Power: An X-Factor in Leadership?

    Science.gov (United States)

    1986-05-01

    Parsons, Oxford University Press, NY, 1947. 3. Zaleznik , Abraham, Charismatic and Consensus Leaders; A Psychological Comparison. An article in...Social Analysis, London, 1938. 11. Zaleznik , Abraham and Kets DeVries, Manfred, F. R., Power and the Corporate Mind, Houghton Mifflin Co., Boston, 9

  17. Altijd verleidelijk dichtbij

    NARCIS (Netherlands)

    Vries, Imar de

    2015-01-01

    abstractDe bijdrage van Imar de Vries over communicatieveinteractie in het telefonische laat zien hoe sterk geïdealiseerde ideeën over communicatie of – in zijn woorden – ‘verlangens naar een communicatief utopia’ een normatief principe vormen in de ontwikkeling van communicatietechnologieën.

  18. SA Journal of Radiology: Editorial Policies

    African Journals Online (AJOL)

    Editorial Board. Editor-in-chief. Ian Duncan Guest editor. S. Beningfield Production editor. Julia Casciola Editorial board. Coert de Vries Leonie Scholtz Darius Tsatsi Savvas Andronikou Peter Corr Alan Scher Steve Beningfield Malan van Rensburg Mala Modi. ISSN: 2078-6778. AJOL African Journals Online. HOW TO USE ...

  19. Improving the Sequential Time Perception of Teenagers with Mild to Moderate Mental Retardation with 3D Immersive Virtual Reality (IVR)

    Science.gov (United States)

    Passig, David

    2009-01-01

    Children with mental retardation have pronounced difficulties in using cognitive strategies and comprehending abstract concepts--among them, the concept of sequential time (Van-Handel, Swaab, De-Vries, & Jongmans, 2007). The perception of sequential time is generally tested by using scenarios presenting a continuum of actions. The goal of this…

  20. South African Medical Journal - Vol 106, No 6 (2016)

    African Journals Online (AJOL)

    Psoriatic arthritis: An assessment of clinical, biochemical and radiological features in a single-centre South African cohort · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. AB Maharaj, M Rajkaran, J Govender, K Maharaj, N de Vries, PP Tak, 630-633.

  1. African Journal of Drug and Alcohol Studies - Vol 11, No 2 (2012)

    African Journals Online (AJOL)

    ... knowledge, and attitudes of adult s residing in communities taking part in the FAS prevention study in South Africa · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. CDH Parry, JP Gossage, A-S Marais, R Barnard, M de Vries, J Blankenship, S Seedat, PA May ...

  2. Comparison of baseline drinking practices, knowledge, and attitudes ...

    African Journals Online (AJOL)

    Comparison of baseline drinking practices, knowledge, and attitudes of adult s residing in communities taking part in the FAS prevention study in South Africa. CDH Parry, JP Gossage, A-S Marais, R Barnard, M de Vries, J Blankenship, S Seedat, PA May ...

  3. DYNAMIND: Naar dynamisch en gestructureerd vraaggestuurd leren met digitaal mindmappen

    NARCIS (Netherlands)

    Harry Stokhof; Haske van Vlokhoven; Martijn Peters; Dominique Sluijsmans

    2011-01-01

    Werken met papieren mindmaps lijkt echter nog onvoldoende uit te nodigen tot het herzien en herschikken van conceptuele verbanden (Stokhof, De Vries 2009). Mindmapping via meer dynamische tools lijkt dit meer mogelijk te maken. In dit quasi-experimentele exploratieve onderzoek worden twee vragen

  4. Alfred Schaffer

    African Journals Online (AJOL)

    Owner

    Zijn op- komst in de voorstad (2000), Dwaalgasten (2002),. Geen hand voor ogen (2004), Schuim (2006) en. Kooi (2008)––word in hierdie keur verteen- woordig, maar streng verteenwoordigend van sy oeuvre is Kom in, dit vries daar buite nie,.

  5. Two-soliton and three-soliton interactions of electron acoustic waves ...

    Indian Academy of Sciences (India)

    of the Kortweg–de Vries (KdV) equation [2]. On the other hand, electron acoustic waves (EAWs) do exhibit soliton solutions and have been investigated in detail both theoretically and experimentally by many resear- chers [3–5]. The evolution of small-amplitude EAWs in collisionless plasma is usually. Pramana – J. Phys.

  6. Hepatitis E virus: a review

    Czech Academy of Sciences Publication Activity Database

    Vašíčková, P.; Pšikal, I.; Králík, P.; Widen, F.; Hubálek, Zdeněk; Pavlík, I.

    2007-01-01

    Roč. 52, č. 9 (2007), s. 365-384 ISSN 0375-8427 Institutional research plan: CEZ:AV0Z60930519 Keywords : risk assessment * food safety * food borne viral outbreaks * zoonoses * pigs Subject RIV: EE - Microbiology, Virology Impact factor: 0.645, year: 2007 http://www.vri.cz/docs/vetmed/52-9-365.pdf

  7. Disease: H00940 [KEGG MEDICUS

    Lifescience Database Archive (English)

    Full Text Available lia E, Kokotas H, Gasparini P, Giannoulia-Karantana A, Renieri A, Zeviani M, Petersen MB Cohen syndrome resu...ccola B, Zelante L, Hamel CP, Sarda P, Lalani SR, Grasso R, Buoni S, Hayek J, Servais L, de Vries BB, Georgoudi N, Nakou S, Peters

  8. Analytical and Experimental Characterization of Thick-Section Fiber-Metal Laminates

    Science.gov (United States)

    2013-06-01

    CONCLUSIONS Bibliography [1] R. C. Alderliesten, M. Hagenbeek, J. J. Homan , P. A. Hooijmeijer, T. J. de Vries, and C. A. J. R. Vermeeren. Fatigue and...1982. [9] J. J. Homan . Fatigue initiation in fibre metal laminates. International Journal of Fatigue, 28(4): 366–374, 2006. [10] M. Kashtalyan and C

  9. Serious games at the UNHCR with ARLearn, a toolkit for mobile and virtual reality applications

    NARCIS (Netherlands)

    Gonsalves, Atish; Ternier, Stefaan; De Vries, Fred; Specht, Marcus

    2012-01-01

    Gonsalves, A., Ternier, S., De Vries, F., & Specht, M. (2012). Serious games at the UNHCR with ARLearn, a toolkit for mobile and virtual reality applications. In M. Specht, M. Sharples, & J. Multisilta (Eds.), Proceedings of 11th World Conference on Mobile and Contextual Learning (mLearn 2012) (pp.

  10. Serious games at the UNHCR with ARLearn, a toolkit for mobile and virtual reality applications

    NARCIS (Netherlands)

    Gonsalves, Atish; Ternier, Stefaan; De Vries, Fred; Specht, Marcus

    2013-01-01

    Gonsalves, A., Ternier, S., De Vries, F., & Specht, M. (2012, 16-18 October). Serious games at the UNHCR with ARLearn, a toolkit for mobile and virtual reality applications. Presentation given at the 11th World Conference on Mobile and Contextual Learning (mLearn 2012), Helsinki, Finland.

  11. The Influence of Cognitive and Non-Cognitive Factors on the Development of Rifle Marksmanship Skills. CRESST Report 753

    Science.gov (United States)

    Chung, Gregory K. W. K.; Nagashima, Sam O.; Espinosa, Paul D.; Berka, Chris; Baker, Eva L.

    2009-01-01

    In this report, researchers examined rifle marksmanship development within a skill development framework outlined by Chung, Delacruz, de Vries, Bewley, and Baker (2006). Thirty-three novice shooters used an M4 rifle training simulator system to learn to shoot an 8-inch target at a simulated distance of 200 yards. Cognitive, psychomotor, and…

  12. ibu", oj, salihu, sae, luther, jn, suraj, k., ceaser, a” abechi, a .s., aba

    African Journals Online (AJOL)

    The recent introduction of PPR homologous vaccine by N VRI Vom for sheep and goats could eventually lead to the control of the disease. The-definition of the role of other animal species in the epidemiology of PPR at this stage is therefore necessary. This study was carried out to detect not only viral antibodies in serum.

  13. 16 Resensies 03 Nel WEB.pmd

    African Journals Online (AJOL)

    Owner

    Was dit wat Goethe bedoel het met verwondering as die hoogste waartoe die mens in staat is?” Uiteindelik gaan sien dan telkens oor in insig, “soms toegedraai in byna vergete ondervindings” (123), soos wat die verteller in die aangrypende slotverhaal. “Oor goeterse en woorde” bely. Soos in talle ander De Vries-verhale ...

  14. Slegs eenmaal gedoop - Sans Jamais Le Réitérer*

    African Journals Online (AJOL)

    baptism administered with water in the 'Name of the. Father and of the Son and of the Holy Spirit' by a ..... Die kwessie van herdoop kom ook vry uitvoerig aan die orde by Thomas Aqui nas (ST III q66 ix). Hy sluit sterk by Augustinus ..... S Thomae de Aquino Summa Theologiae, 1953. Ed Commissio Piana. Ottawa: Harpell's,.

  15. Speed control variable rate irrigation

    Science.gov (United States)

    Speed control variable rate irrigation (VRI) is used to address within field variability by controlling a moving sprinkler’s travel speed to vary the application depth. Changes in speed are commonly practiced over areas that slope, pond or where soil texture is predominantly different. Dynamic presc...

  16. Perceptions and attitudes of secondary school students in KwaZulu ...

    African Journals Online (AJOL)

    Perceptions and attitudes of secondary school students in KwaZulu Natal towards virginity testing. M Taylor, SB Dlamini, R Sathiparsad, C Jinabhai, H de Vries. Abstract. This study describes the prevalence of virginity testing (VT) amongst rural secondary school students in KwaZulu- Natal (KZN), compares the attitudes of ...

  17. Public attitude towards modern biotechnology

    African Journals Online (AJOL)

    Jane

    2011-09-30

    Sep 30, 2011 ... 12. Malaysian Institution for Nuclear Technology (MINT). 13. Forest Research Institute of Malaysia (FRIM). 14. Veterinary Research Institution (VRI). ... ment of modern biotechnology in Malaysia. A study by communication researchers from ISAAA and the. University of Illinois at Urbana-Champaign (2003).

  18. Diagnosis, monitoring and treatment of tuberous sclerosis complex ...

    African Journals Online (AJOL)

    NC 4.0. Diagnosis, monitoring and treatment of tuberous sclerosis complex: A South African consensus response to international guidelines. P J de Vries,1 MB ChB, MRCPsych, PhD; L Leclezio,1 MSc (Med) Neurosci; J M Wilmshurst,2 MB BS, ...

  19. Group formalism of Lie transformations to time-fractional partial ...

    Indian Academy of Sciences (India)

    2015-10-16

    Oct 16, 2015 ... time-fractional diffusive equation and; time-fractional cylindrical Korteweg–de Vries equation. Using the Lie point symmetries obtained, we show that each of them has been transformed into ordinary differential equation of fractional order with a new independent variable. We also explain how exact or ...

  20. Quantitative volumetric Raman imaging of three dimensional cell cultures

    KAUST Repository

    Kallepitis, Charalambos

    2017-03-22

    The ability to simultaneously image multiple biomolecules in biologically relevant three-dimensional (3D) cell culture environments would contribute greatly to the understanding of complex cellular mechanisms and cell–material interactions. Here, we present a computational framework for label-free quantitative volumetric Raman imaging (qVRI). We apply qVRI to a selection of biological systems: human pluripotent stem cells with their cardiac derivatives, monocytes and monocyte-derived macrophages in conventional cell culture systems and mesenchymal stem cells inside biomimetic hydrogels that supplied a 3D cell culture environment. We demonstrate visualization and quantification of fine details in cell shape, cytoplasm, nucleus, lipid bodies and cytoskeletal structures in 3D with unprecedented biomolecular specificity for vibrational microspectroscopy.

  1. Photometric Observations and Light Curve Analysis of BL Eridani

    Directory of Open Access Journals (Sweden)

    Wonyong Han

    2006-12-01

    Full Text Available We present light curves of a short period binary system BL Eridani. The light curves were observed with {it VRI} filters by a 50cm wide field robotic telescope at Siding Spring Observatory (SSO, equipped with a 2K CCD camera, which was developed by Korea Astronomy and Space Science Institute (KASI, and Yonsei University Observatory (YUO. The photometric observations were made on 6 nights by automatic operation mode and remote observation mode at SSO and KASI in Korea, respectively. We obtained new {it VRI} CCD light curves and new 5 times of minima, and analyzed the light curves with the Wilson & Deviney (1971 binary 2005 version and derived the new photometric solutions. The mass ratio q = 0.48 in this study shows different value with earlier investigators. According to the model analysis, it is considered that the BL Eri system is currently undergoing contact stage of the two binary components, rather than near-contact stage.

  2. A Dutch perspective: the limits of lawful euthanasia.

    Science.gov (United States)

    de Vries, Ubaldus

    2004-01-01

    Dutch author Ubaldus de Vries reviews the current state of the euthanasia law in the Netherlands. The legislation, enacted in 2001, creates a medical exception that allows for euthanasia in cases where patients experience "hopeless and unbearable suffering." A brief history of the Dutch approach to euthanasia is set forth, case law is reviewed, and the unique role of the doctor is examined in seeking to understand the extent of one's right to euthanasia in the Netherlands. Because the courts must determine what constitutes "hopeless and unbearable suffering," Professor de Vries analyzes the judicial interpretation of "suffering" and concludes that judicial interpretation has reached its limits, and thus by implication, the limits of lawful euthanasia have been reached.

  3. Quantitative volumetric Raman imaging of three dimensional cell cultures

    Science.gov (United States)

    Kallepitis, Charalambos; Bergholt, Mads S.; Mazo, Manuel M.; Leonardo, Vincent; Skaalure, Stacey C.; Maynard, Stephanie A.; Stevens, Molly M.

    2017-03-01

    The ability to simultaneously image multiple biomolecules in biologically relevant three-dimensional (3D) cell culture environments would contribute greatly to the understanding of complex cellular mechanisms and cell-material interactions. Here, we present a computational framework for label-free quantitative volumetric Raman imaging (qVRI). We apply qVRI to a selection of biological systems: human pluripotent stem cells with their cardiac derivatives, monocytes and monocyte-derived macrophages in conventional cell culture systems and mesenchymal stem cells inside biomimetic hydrogels that supplied a 3D cell culture environment. We demonstrate visualization and quantification of fine details in cell shape, cytoplasm, nucleus, lipid bodies and cytoskeletal structures in 3D with unprecedented biomolecular specificity for vibrational microspectroscopy.

  4. The polymorphic prelude to Bateson-Dobzhansky-Muller incompatibilities.

    Science.gov (United States)

    Cutter, Asher D

    2012-04-01

    Speciation research has largely assumed that the genetic causes of reproductive isolation are the work of fixed, divergent alleles that interact to cause genetic problems in hybrids: Bateson-Dobzhansky-Muller incompatibilities. However, many recent studies demonstrate substantial heritable polymorphism within species for hybrid incompatibility, herein called variable reproductive isolation (VRI). In this review, I outline the causes and importance of this general phenomenon. I also identify the new challenges of quantifying the relative contributions to reproductive isolation of fixed alleles versus polymorphisms, and the change in these contributions over the course of speciation. Explicit integration of VRI into speciation theory will help to quantify the relative roles of genetic drift and selection in speciation, but this synthesis requires substantial new contributions from both theory and empirical studies. Copyright © 2011 Elsevier Ltd. All rights reserved.

  5. Operation New Arrivals. Phase I - The Buildup, 27 April 1975 - 23 May 1975. Part I

    Science.gov (United States)

    1975-07-01

    10 July I’-^S AUTC Office of History bglin Air l-’orcc Base, Florida iv *i(«l^w".ir^W J«’^’ uHt ’"i"’’**1,,H’ ’■"* .-^-■iVri.^^,,, ^^:..^.«l...FOLLOWI^C ADDITIONAL ITEMS ARE ßEING USED, CONSUMPTION 0 AT A NOT AVAILABLE. FLOIJR PUWDERPO MILK CANNED PEACHES SUGAR TOMATO SOUP SOY SAUCE

  6. Revisión de libros

    Directory of Open Access Journals (Sweden)

    Andrade C. M. Gonzalo

    1991-12-01

    Full Text Available Referencias Bibliográficas Recomendadas: DeVries, Ph. J. 1987. The Butterflies of Costa Rica and their natural history. Princeton University Press, Princeton, New Jersey, 327 pp. ISBN 0-691-02403-0Blanco Fernández de Caleya, P. & A. del Valle Stervinou. Herbarium Mutisianum. Fontqueria 32, Madrid, 1991. ISSN 0212-0623. 173 págs.

  7. Understanding the organizational integration of subcontracted tasks in inter-firm projects

    OpenAIRE

    Stephan Scheuner

    2011-01-01

    Project management researchers have recently emphasized the prevalence of inter-firm projects, i.e. projects which are carried out by multiple partners and hence cut across the organizational boundaries of one firm, in today’s business world (Bakker, Knoben, de Vries, & Oerlemanns, in Press). Especially in projects concerned with the delivery of what Hobday (Hobday, 1998) named complex products and systems (CoPS), where a diverse set of technological competences and high project budgets often...

  8. Et demain l'agriculture? : options techniques et mesures politiques pour un developpement agricole durable en Afrique subsaharienne : cas du Cercle de Koutiala en zone sud du Mali

    OpenAIRE

    Sissoko, K.

    1998-01-01

    Global situation in Sub-Saharan countries
    Economic development in the Sub-Saharan countries is strongly linked to the agricultural sector, which constitutes the major part of gross national product (GNP) in most of these countries. However, agricultural productivity and production in the area are very low due to erratic rainfall and especially the low level of soil fertility (Penning de Vries & Djitèye, 199; van Keulen &...

  9. From the Skin to the Brain: Pathophysiology of Colonization and Infection of External Ventricular Drain, a Prospective Observational Study.

    Science.gov (United States)

    Mounier, Roman; Lobo, David; Cook, Fabrice; Martin, Mathieu; Attias, Arie; Aït-Mamar, Bouziane; Gabriel, Inanna; Bekaert, Olivier; Bardon, Jean; Nebbad, Biba; Plaud, Benoît; Dhonneur, Gilles

    2015-01-01

    Ventriculostomy-related infection (VRI) is a serious complication of external ventricular drain (EVD) but its natural history is poorly studied. We prospectively tracked the bacteria pathways from skin towards ventricles to identify the infectious process resulting in ventriculostomy-related colonization (VRC), and VRI. We systematically sampled cerebrospinal fluid (CSF) on a daily basis and collected swabs from both the skin and stopcock every 3.0 days for microbiological analysis including in 101 neurosurgical patient. Risk factors for positive event defined as either VRC or VRI were recorded and related to our microbiological findings. A total of 1261 CSF samples, 473 skin swabs, and 450 stopcock swabs were collected. Skin site was more frequently colonized than stopcock (70 (60%) vs 34 (29%), p = 0.023), and earlier (14 ±1.4 vs 24 ±1.5 days, p<0.0001). Sixty-one (52%) and 32 (27%) skin and stopcock sites were colonized with commensal bacteria, 1 (1%) and 1 (1%) with pathogens, 8 (7%) and 1 (1%) with combined pathogens and commensal bacteria, respectively. Sixteen positive events were diagnosed; a cutaneous origin was identified in 69% of cases. The presence of a pathogen at skin site (6/16 vs 4/85, OR: 11.8, [2.5-56.8], p = 0.002) and CSF leakage (7/16 vs 6/85, OR 10 [2.4-41.2], p = 0.001)) were the two independent significant risk factors statistically linked to positive events occurrence. Our results suggest that VRC and VRI mainly results from an extra-luminal progression of pathogens initially colonizing the skin site where CSF leaks.

  10. From the Skin to the Brain: Pathophysiology of Colonization and Infection of External Ventricular Drain, a Prospective Observational Study.

    Directory of Open Access Journals (Sweden)

    Roman Mounier

    Full Text Available Ventriculostomy-related infection (VRI is a serious complication of external ventricular drain (EVD but its natural history is poorly studied. We prospectively tracked the bacteria pathways from skin towards ventricles to identify the infectious process resulting in ventriculostomy-related colonization (VRC, and VRI. We systematically sampled cerebrospinal fluid (CSF on a daily basis and collected swabs from both the skin and stopcock every 3.0 days for microbiological analysis including in 101 neurosurgical patient. Risk factors for positive event defined as either VRC or VRI were recorded and related to our microbiological findings. A total of 1261 CSF samples, 473 skin swabs, and 450 stopcock swabs were collected. Skin site was more frequently colonized than stopcock (70 (60% vs 34 (29%, p = 0.023, and earlier (14 ±1.4 vs 24 ±1.5 days, p<0.0001. Sixty-one (52% and 32 (27% skin and stopcock sites were colonized with commensal bacteria, 1 (1% and 1 (1% with pathogens, 8 (7% and 1 (1% with combined pathogens and commensal bacteria, respectively. Sixteen positive events were diagnosed; a cutaneous origin was identified in 69% of cases. The presence of a pathogen at skin site (6/16 vs 4/85, OR: 11.8, [2.5-56.8], p = 0.002 and CSF leakage (7/16 vs 6/85, OR 10 [2.4-41.2], p = 0.001 were the two independent significant risk factors statistically linked to positive events occurrence. Our results suggest that VRC and VRI mainly results from an extra-luminal progression of pathogens initially colonizing the skin site where CSF leaks.

  11. Serological survey of the wild boar (Sus scrofa) for tularaemia and brucellosis in South Moravia, Czech Republic

    Czech Academy of Sciences Publication Activity Database

    Hubálek, Zdeněk; Treml, F.; Juřicová, Zina; Huňady, M.; Halouzka, Jiří; Janík, V.; Bill, D.

    2002-01-01

    Roč. 47, 2-3 (2002), s. 60-66 ISSN 0375-8427 R&D Projects: GA ČR GA524/00/1122; GA AV ČR IBS6093007; GA AV ČR KSK6005114 Keywords : Sus scrofa * serosurvey * zoonoses Subject RIV: GJ - Animal Vermins ; Diseases, Veterinary Medicine Impact factor: 0.204, year: 2002 http://www.vri.cz/docs/vetmed/47-3-60.pdf

  12. The Solar Neighborhood. 35. Distances to 1404 M Dwarf Systems Within 25 PC in the Southern Sky

    Science.gov (United States)

    2015-01-01

    because we first estimated a distance photometrically from Super- COSMOS plates, then measured VRI photometry to yield a more accurate ccddist, then...pltdists, 96 systems have ccddists based on unresolved photometry because their separations areə″. In addition, photometry from the SAAO extracted from...3.3. JHKs Photometry from 2MASS Infrared photometry in the JHKs (hereafter simply JHK ) system has been extracted from 2MASS (Skrutskie et al. 2006

  13. Homeland Security: Developing National Doctrine to Guide State Strategy Development

    Science.gov (United States)

    2012-03-01

    James Monroe in 1823 ( Martin , n.d.). There is also political doctrine, such as egalitarianism a “political doctrine that holds that all people...be able to engage a larger stakeholder community and avoid the need for a huge new bureaucracy (Linde, O’Brien, Lindstrom , Spiegeleire, Vayrynen...Presentation, Osan Air Force Base, South Korea. 74 Linde, E., O’Brien, K., Lindstrom , G., Spiegeleire, S., Vayrynen, M., & de Vries, H. (2002

  14. One-Parametric Family of the Double-Scaling Limits in the Hermitian Matrix Model $\\Phi^6:$ Onset of Nondissipative Shock Waves

    OpenAIRE

    Kudashev, Vadim R.; Suleimanov, Bulat I.

    1998-01-01

    We construct a one-parametric family of the double-scaling limits in the hermitian matrix model $\\Phi^6$ for 2D quantum gravity. The known limit of Bresin, Marinari and Parisi belongs to this family. The family is represented by the Gurevich-Pitaevskii solution of the Korteveg-de Vries equation which describes the onset of nondissipative shock waves in media with small dispersion. Numerical simulation of the universal Gurevich-Pitaevskii solution is made.

  15. Institutional and Organizational Unconscious Theories: An Alternative Way for Explaining Challenges in Inter-Agency Cooperation

    Science.gov (United States)

    2012-10-01

    87] Denhardt, Robert B. (1989), pp.78-83. [88] Bedin, V., M. Fournier et al. (2008). La bibliothèque idéale des sciences humaines , Auxerre...Éditions Sciences humaines , pp.194-196. [89] Bedin, V., M. Fournier et al. (2008), pp.223-226. [90] Kets de Vries, Manfred F. R. and Danny Miller...Pierre-Marc Lanteigne Canadian Forces College Scientific Authority: Paul Chouinard DRDC Centre for Security Science The scientific or

  16. AcEST: DK959953 [AcEST

    Lifescience Database Archive (English)

    Full Text Available PP HS+S EY +YD++ Sbjct: 1186 LPPPPAHPPPHSNSEEYSMSVDESYDQE 1213 >sp|O89026|ROBO1_MOUSE Roundabout homolog 1 OS=Mus musculus GN=Robo1...ry: 205 YNI 213 I Sbjct: 179 VRI 181 >sp|O55005|ROBO1_RAT Roundabout homolog 1 OS=Rattus norvegicus GN=Rob...o1 PE=2 SV=1 Length = 1651 Score = 29.3 bits (64), Expect = 6.4 Identities = 13/28

  17. User’s Guide for the Longitudinal Scalogram Analysis Program

    Science.gov (United States)

    1991-01-01

    Total n = 791. 0 = not passed, I = passed. Items am legal drugs , cannabis, pills, psychedelics , cocaine, and heroin. Asterisks denote longitudinal...ALERT to model stages of drug use involvement in adolescents. This revision of the original Note adds new information about the computation of...including intellectual development (e.g., Bayley, 1955), drug use involvement (e.g., Kandel, 1975), moral development (Walker, deVries, and Bichard, 1984

  18. Savisaar võtab raudtee uuelt omanikult liiprid / Mikk Salu

    Index Scriptorium Estoniae

    Salu, Mikk, 1975-

    2006-01-01

    Autori väitel töötab majandus- ja kommunikatsiooniminister Edgar Savisaar niisuguse arengu nimel, mille kohaselt BRS-i ostja pakub infrastruktuuri riigile. LHV koondab Eesti Raudtee (ER) ostuks investorite gruppi. ER otsusest on huvitatud Deutsche Bahn ja Soome riigiraudtee VR Grupp. Vt. samas intervjuud VR-i presidendi Henri Kuituneniga. Lisad: Eesti Raudtee ja tema kosilased; Diplomaatia Peeter I pildi ümber

  19. Analytical solution of nonlinear space–time fractional differential equations using the improved fractional Riccati expansion method

    Directory of Open Access Journals (Sweden)

    Emad A-B. Abdel-Salam

    2015-06-01

    Full Text Available In this paper, the improved fractional Riccati expansion method is proposed to solve fractional differential equations. The method is applied to solve space–time fractional modified Korteweg–de Vries equation, space–time fractional modified regularized long-wave equation, time fractional biological population model, and space–time fractional Klein–Gordon equation. The obtained solutions include generalized trigonometric and hyperbolic functions solutions. Among these solutions, some are found for the first time.

  20. Multifactorial assessment and targeted intervention to reduce falls among the oldest-old: a randomized controlled trial

    OpenAIRE

    Ferrer A; Formiga F; Sanz H; de Vries OJ; Badia T; Pujol R

    2014-01-01

    Assumpta Ferrer,1 Francesc Formiga,2,3 Héctor Sanz,4 Oscar J de Vries,5 Teresa Badia,6 Ramón Pujol2,3 On behalf of the OCTABAIX Study Group 1Primary Healthcare Centre "El Plà" CAP-I, Sant Feliu de Llobregat, 2Geriatric Unit, Internal Medicine Service, Hospital Universitari de Bellvitge, 3Bellvitge Biomedical Research Institute, IDIBELL, L'Hospitalet de Llobregat, 4Support Research Unit, Primary Health Department Costa Ponent, IDIAP Jo...

  1. Exploring the function of relative sentences in New Testament Greek

    African Journals Online (AJOL)

    2015-08-14

    Aug 14, 2015 ... (3) Qualifying a verb with regard to time, location or manner. (4). Functioning as a conjoined sentence. .... Dutch, Korean, Abkhaz, Basque, Lahu and Nama (De Vries. 2006:234–235, 264). The function of relative ... sometimes used for τίς after verbs of 'knowing' (cf. Lk. 9:33e.: μὴ εἰδὼς ὃ λέγει ['not knowing ...

  2. The National Shipbuilding Research Program, Computer Aided Process Planning for Shipyards

    Science.gov (United States)

    1986-08-01

    WASHINGTON STREET BATH, MAINE 04530 COMPUTER-AIDED POCESS PLANNING BIBLIOGRAPHY Compiled by Richard L. DeVries, Project Manager Bath Iron Works...understand and guide the process.” II-3 "A Review of Computer-Aided Process Planning Systems” J. D. Burgess, Swinburne Institute of Technology SME... Richard A. Wysk, Pennsylvania State University Journal of Manufacturing Systems (1983), Volume 2, No. 2, Pages 127-135. “Two approaches to Computer

  3. Molecular Heterogeneity in Primary and Metastatic Prostate Tumor Tissue

    Science.gov (United States)

    2015-06-01

    European Ancestry ). For the test cohort, genotyping was performed at the Harvard Medical School Partners Healthcare Center for Genetics and Genomics...Bazelier MT, Vestergaard P, Leufkens HG, Schmidt MK, de Vries F, et al. Use of metformin and survival of diabetic women with breast cancer. Curr Drug Saf...cancer-specific survival of diabetic women with HER2+ breast cancer. Ann Oncol 2012;23:1771-80. 117. Allott EH, Abern MR, Gerber L, Keto CJ

  4. Pärlid mustalt turult / Pekka Erelt

    Index Scriptorium Estoniae

    Erelt, Pekka, 1965-

    2010-01-01

    Kadrioru Kunstimuuseumi näitusel "Šedöövri sünd" eksponeeritud maalide päritolust. Suur osa kunstiteostest osteti Moskvast ja Petrogradist. Lähemalt järgmistest maalidest: Lambert Jacobsz "Õhtusöök Emmauses", Hieronymus Boschi lähikondne "Rahavahetajate ja kaubitsejate väljaajamine templist", Andrea Vaccaro ateljee "Simson ja Delila", Jacob Jordaens "Püha perekond", Franz Xaver Winterhalter "Vürstinna Olimpiada Barjatinskaja portree"

  5. A Program Manager’s Guide for Program Improvement in Ongoing Psychological Health and Traumatic Brain Injury Programs. The RAND Toolkit, Volume 4

    Science.gov (United States)

    2014-01-01

    seek care at a specific referral site (based on a computer algorithm that identifies the site nearest to the caller’s home address); (b) offers to...Thousand Oaks, CA: SAGE Publications, 2008. de Vries H, Weijts W, Dijkstra M, Kok G. “The Utilization of Qualitative and Quantitative Data for Health...Health and Traumatic Brain Injury. “Program Evaluation Guide.” 2012. As of March 27, 2013: http://www.dcoe.health.mil/Content/ Navigation /Documents

  6. Creating and developing local political brand identity: a constituency focus

    OpenAIRE

    Armannsdottir, G; Pich, C; Spry, L

    2016-01-01

    Political brands are complex multilayered entities that can be segmented into corporate political brands otherwise known as Parties and individual-sub political brands often conceptualised as individual politicians and candidates (Cwalina and Falkowski 2014; De Landtsheer and De Vries, 2015; Milewicz and Milewicz 2014; Speed, Butler and Colins 2015). Research into individual-sub political brands has received little attention compared with corporate political brands with calls for more researc...

  7. On some properties of SU(3 fusion coefficients

    Directory of Open Access Journals (Sweden)

    Robert Coquereaux

    2016-11-01

    Full Text Available Three aspects of the SU(3 fusion coefficients are revisited: the generating polynomials of fusion coefficients are written explicitly; some curious identities generalizing the classical Freudenthal–de Vries formula are derived; and the properties of the fusion coefficients under conjugation of one of the factors, previously analyzed in the classical case, are extended to the affine algebra suˆ(3 at finite level.

  8. Reference: 266 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available 266 http://metadb.riken.jp/db/SciNetS_ria224i/cria224u4ria224u16146519i Bagherieh-Najjar Mohammad...s recombination and modulates DNA damage responses. 6 789-98 16146519 2005 Sep The Plant journal Bagherieh-Najjar Mohammad B|Dijkwel Paul P|Hille Jacques|de Vries Onno M H

  9. Organizational Stress: A Literature Review 1974-1982.

    Science.gov (United States)

    1983-01-01

    other *workers. Zaleznik , Kets de Vries, and Howard (1977) examined stress reactions among high-status members of a large organization. Compared with...cardiovascular, gastrointestinal, and allergy-respiratory disturbances ( Zaleznik , et al, p. 4) de-valued self-conception (Lauer, p. 9) The following... Zaleznik et al, p. 4) o ego-involvement, commitment to country (Sohlberg, p. 20) 24 The references discussed below have not been previously described

  10. The Epidemiology of Guillain-Barre Syndrome in U.S. Military Personnel: A Case-Control Study

    Science.gov (United States)

    2009-08-26

    unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT Background: Guillain - Barr ?yndrome (GBS), the leading cause of acute flaccid paralysis worldwide, is an...References 1. Frenzen PD: Economic cost of Guillain - Barre syndrome in the United States. Neurology 2008, 71(1):21-7. Table 3: Risk factors and covariates...Madle GC, Seaman HE, e Vries CS: The epidemiol- ogy of Guillain - Barre syndrome worldwide A systematic lit- erature review. Neuroepidemiology 2009, 32(2

  11. Effect of dust size distribution on ion-acoustic solitons in dusty plasmas with different dust grains

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Dong-Ning; Yang, Yang; Yan, Qiang [Northwest Normal University, College of Physics and Electronic Engineering (China); Wang, Xiao-Yun [Lanzhou Jiao Tong University, Department of Mathematics and Physics (China); Duan, Wen-Shan, E-mail: duanws@126.com [Northwest Normal University, College of Physics and Electronic Engineering (China)

    2017-02-15

    Theoretical studies are carried out for ion acoustic solitons in multicomponent nonuniform plasma considering the dust size distribution. The Korteweg−de Vries equation for ion acoustic solitons is given by using the reductive perturbation technique. Two special dust size distributions are considered. The dependences of the width and amplitude of solitons on dust size parameters are shown. It is found that the properties of a solitary wave depend on the shape of the size distribution function of dust grains.

  12. Prevalence of canine distemper virus in wild mustelids in the Czech Republic and a case of canine distemper in young stone martens

    Czech Academy of Sciences Publication Activity Database

    Pavlačík, L.; Celer, V.; Koubek, Petr; Literák, I.

    2007-01-01

    Roč. 52, č. 2 (2007), s. 69-73 ISSN 0375-8427 R&D Projects: GA AV ČR IBS6093003 Institutional research plan: CEZ:AV0Z60930519 Keywords : genus Morbillivirus * direct immunofluorescence test * serology * Eurasian badger * stone marten Subject RIV: GJ - Animal Vermins ; Disease s, Veterinary Medicine Impact factor: 0.645, year: 2007 http://www.vri.cz/docs/vetmed/52-2-69.pdf

  13. On charisma and need for leadership

    OpenAIRE

    Vries, R.E. de; Roe, R.A.; Taillieu, T.C.B.

    1997-01-01

    Some scholars have argued and found that the relationship between transformational leadership and outcomes can be moderated by subordinate or situational characteristics (e.g. Bass and Avolio, 1990; Podsakoff, MacKenzie, and Bommer, 1995). Still, there is insufficient evidence on this issue. In this paper we examine need for leadership (De Vries, 1997) as a moderator of the relation between a measure for charismatic leadership (Bass, 1985a; Den Hartog, Koopman & Van Muijen, 1994) and subordin...

  14. Review of the Book - Teaching about Technology: An Introduction to the Philosophy of Technology for Non-Philosophers

    OpenAIRE

    Childress, Vincent

    2006-01-01

    Marc de Vries' latest book, Teaching about Technology: An Introduction to the Philosophy of Technology for Non-Philosophers, was interesting to the reviewer because it provided a link between philosophies of technology and the nature of the technology curriculum more than any other philosophy-related work he has read. The book is intended for use with pre-service teachers, graduate students, and others who are interested in teaching technology. Teaching about Technology is part of a series of...

  15. Enhanced Vapor-Phase Diffusion in Porous Media - LDRD Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Ho, C.K.; Webb, S.W.

    1999-01-01

    As part of the Laboratory-Directed Research and Development (LDRD) Program at Sandia National Laboratories, an investigation into the existence of enhanced vapor-phase diffusion (EVD) in porous media has been conducted. A thorough literature review was initially performed across multiple disciplines (soil science and engineering), and based on this review, the existence of EVD was found to be questionable. As a result, modeling and experiments were initiated to investigate the existence of EVD. In this LDRD, the first mechanistic model of EVD was developed which demonstrated the mechanisms responsible for EVD. The first direct measurements of EVD have also been conducted at multiple scales. Measurements have been made at the pore scale, in a two- dimensional network as represented by a fracture aperture, and in a porous medium. Significant enhancement of vapor-phase transport relative to Fickian diffusion was measured in all cases. The modeling and experimental results provide additional mechanisms for EVD beyond those presented by the generally accepted model of Philip and deVries (1957), which required a thermal gradient for EVD to exist. Modeling and experimental results show significant enhancement under isothermal conditions. Application of EVD to vapor transport in the near-surface vadose zone show a significant variation between no enhancement, the model of Philip and deVries, and the present results. Based on this information, the model of Philip and deVries may need to be modified, and additional studies are recommended.

  16. Evaluation of vitreoretinal interface changes in patients receiving intravitreal anti-VEGF therapy.

    Science.gov (United States)

    Kinra, Vartika; Singh, Satvir; Khanduja, Sumeet; Nada, Manisha

    2017-03-15

    To study the effects of repeated intravitreal injection of anti-VEGF drug bevacizumab on the vitreoretinal interface (VRI). Patients undergoing intravitreal injection of bevacizumab were enrolled. Eyes with media haze, uveitis, high myopia, history of cataract surgery or laser capsulotomy in last 6 months and complicated pseudophakia were excluded. VRI evaluation was done monthly for a minimum of 6 months. The nature and timing of the change(s) event was recorded. A total of 100 eyes were evaluated. Thirty-seven eyes developed new vitreoretinal interface change event (VICE). Pseudophakia (OR = 5.23, 95% CI = 1.99-14.07, p = 0.001), pre-injection VRI abnormality (OR = 2.63, 95% CI = 1.13-6.14, p = 0.024) and older age at enrollment (62.6 ± 13.9 vs. 56.3 ± 14 years) were risk factors for development of VICE. Eighty percent of interface events occurred in the first 3 months of therapy. Eight needed surgical intervention for consequences of vitreoretinal separation. VICE is not infrequent in eyes receiving anti-VEGF therapy though rarely need surgical intervention. The first 3 months are the critical months to watch out for these events. The treating ophthalmologists must keep the risk factors for development of in mind and monitor and counsel patients accordingly.

  17. Variability in the hydrology of the Ikpoba River system | Iloba ...

    African Journals Online (AJOL)

    The variability in some physico-chemical parameters was studied in Ikpoba River from June to November, 2009, in three stations. The study shows high variability in transparency, flow velocity, BOD, alkalinity, chloride, nitrate, phosphate with over 40% variability coefficient which is an indication that these parameters ...

  18. Oscillating solitons in nonlinear optics

    Indian Academy of Sciences (India)

    Abstract. Oscillating solitons are obtained in nonlinear optics. Analytical study of the variable- coefficient nonlinear Schrödinger equation, which is used to describe the soliton propagation in those systems, is carried out using the Hirota's bilinear method. The bilinear forms and analytic soliton solutions are derived, and the ...

  19. Analytical solutions of one-dimensional advection–diffusion ...

    Indian Academy of Sciences (India)

    Analytical solutions are obtained for one-dimensional advection –diffusion equation with variable coefficients in a longitudinal finite initially solute free domain,for two dispersion problems.In the first one,temporally dependent solute dispersion along uniform flow in homogeneous domain is studied.In the second problem the ...

  20. Fulltext PDF

    Indian Academy of Sciences (India)

    Bianchi Type-I Universe with wet dark fluid. T Singh and R Chaubey. 447–458. Anisotropic Bianchi-I universe with phantom field and cosmological con- stant. Bikash Chandra Paul and Dilip Paul. 1247–1257. Statistical Physics. Travelling wave-like solutions of the Zakharov–Kuznetsov equation with variable coefficients.

  1. Agarwal VK see Balaji C 331 Ahmad Ishfaq Mir see Kessarkar ...

    Indian Academy of Sciences (India)

    High-resolution satellite image segmentation using ... diffusion equation with variable coefficients in a finite domain. 539. Kumar M ... environment leading to formation of intense thun- derstorms over Kolkata Part I: Doppler radar and satellite observations. 441. Murthy B S. On the influence of spatial heterogeneity on an inter-.

  2. Multigrid solution of the convection-diffusion equation with high-Reynolds number

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jun [George Washington Univ., Washington, DC (United States)

    1996-12-31

    A fourth-order compact finite difference scheme is employed with the multigrid technique to solve the variable coefficient convection-diffusion equation with high-Reynolds number. Scaled inter-grid transfer operators and potential on vectorization and parallelization are discussed. The high-order multigrid method is unconditionally stable and produces solution of 4th-order accuracy. Numerical experiments are included.

  3. Pramana – Journal of Physics | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Home; Journals; Pramana – Journal of Physics; Volume 85; Issue 6. Issue front cover thumbnail. Volume 85, Issue 6. December 2015, pages 1063-1259u. pp 1063-1072. Rogue wave solutions of the nonlinear Schrödinger eqution with variable coefficients · Changfu Liu Yan Yan Li Meiping Gao Zeping Wang Zhengde Dai ...

  4. Journal of Earth System Science | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Earth System Science. Naveen Kumar. Articles written in Journal of Earth System Science. Volume 118 Issue 5 October 2009 pp 539-549. Analytical solutions of one-dimensional advection–diffusion equation with variable coefficients in a finite domain · Atul Kumar Dilip Kumar Jaiswal Naveen ...

  5. Rogue wave solutions of the nonlinear Schrödinger equation with ...

    Indian Academy of Sciences (India)

    In this paper, a unified formula of a series of rogue wave solutions for the standard (1+1)-dimensional nonlinear Schrödinger equation is obtained through exp-function method. Further, by means of an appropriate transformation and previously obtained solutions, rogue wave solutions of the variable coefficient Schrödinger ...

  6. Energy Reduction Strategies for Marine Corps Base Camp Pendleton: Assessment and Recommendations Professional Report

    Science.gov (United States)

    2012-05-07

    several hundred electric dryers were replaced with natural gas dryers , and 5. Sixteen solar powered street lights/flashers were installed in remote...63 Figure 17 – MCB Camp Pendleton Solar Resource Variability...coefficient of performance MBtu Million British thermal units CO2 carbon dioxide MCAS Marine Corps Air Station CSP concentrating solar power MPR Market

  7. Size variation in samples of fossil and recent murid teeth

    NARCIS (Netherlands)

    Freudenthal, M.; Martín Suárez, E.

    1990-01-01

    The variability coefficient proposed by Freudenthal & Cuenca Bescós (1984) for samples of fossil cricetid teeth, is calculated for about 200 samples of fossil and recent murid teeth. The results are discussed, and compared with those obtained for the Cricetidae.

  8. Ionospheric foF2 morphology and response of F2 layer height over ...

    Indian Academy of Sciences (India)

    The F2-layer critical frequency pre-noon peak increases by a factor of 2 more than the post-noon peak as the solar activity increases. The variability coefficient (R) is ... Department of Physics, Kebbi State University of Science and Technology, P.M.B 1144, Aliero, Kebbi State, Nigeria. School of Science and Technology, ...

  9. Survey and new results on boundary-value problems of singular fractional differential equations with impulse effects

    Directory of Open Access Journals (Sweden)

    Yuji Liu

    2016-11-01

    Full Text Available Firstly we prove existence and uniqueness of solutions of Cauchy problems of linear fractional differential equations (LFDEs with two variable coefficients involving Caputo fractional derivative, Riemann-Liouville derivative, Caputo type Hadamard derivative and Riemann-Liouville type Hadamard fractional derivatives with order q in [n-1,n by using the iterative method.

  10. 12 CFR Appendix A to Subpart B of... - Risk-Based Capital Stress Test

    Science.gov (United States)

    2010-01-01

    ... agricultural finance. 5 Each of the variable coefficients has directional relationships that appropriately... Approach to Credit Scoring,” Agricultural Finance Review, 54(1994):39-54. 6 Barry, P. J., P. N. Ellinger, J... counterparties (excluding derivatives) (percent) Cash 0.00 AAA 0.48 AA 1.24 A 1.57 BBB 3.82 Below BBB and Unrated...

  11. Rogue wave solutions of the nonlinear Schrödinger equation with ...

    Indian Academy of Sciences (India)

    solutions of the variable coefficient Schrödinger equation are also obtained. Two free functions of time t and several arbitrary parameters are involved to generate a large number of wave structures. Keywords. Nonlinear Schrödinger equation; exp-function method; breather soliton; rogue wave. PACS Nos 02.30.Jr; 05.45.

  12. PREFACE Integrability and nonlinear phenomena Integrability and nonlinear phenomena

    Science.gov (United States)

    Gómez-Ullate, David; Lombardo, Sara; Mañas, Manuel; Mazzocco, Marta; Nijhoff, Frank; Sommacal, Matteo

    2010-10-01

    includes two papers devoted to the subject. Konopelchenko et al [8] describe critical and degenerate critical points of a scalar function which obeys the Euler-Poisson-Darboux equation in terms of the hodograph solutions of the dispersionless coupled Korteweg-de Vries hierarchies. Finally, Bogdanov [9] considers 2-component integrable generalizations of the dispersionless 2D Toda lattice hierarchy connected with non-Hamiltonian vector fields, similar to the Manakov-Santini hierarchy generalizing the dKP hierarchy. He presents the simplest 2-component generalization of the dispersionless 2DTL equation, being its differential reduction analogous to the Dunajski interpolating system. Some papers in the issue are concerned with methods to construct solutions of integrable systems, while others place more emphasis on studying properties of specific solutions of applicative interest. Among the first approach, the paper by Kaup and van Gorder [10] describes perturbation theory applied to the Inverse Scattering Transform in 3x eigenvalue problems of Zakharov-Shabat's type. Schiebold [11] studies a projection method to construct solutions of the Ablowitz-Kaup-Newell-Segur (AKNS) system, which enables her to write explicit N-soliton solutions in closed form. An example of the second kind is the paper by Biondini and Wang [12], who study in detail the behaviour of line soliton solutions of the 2DTL, describing their directions and amplitudes and also the richness of their interactions, which include resonant soliton interactions and web structure. An important field of study in integrable systems relates to the singularity structure of the solutions to nonlinear equations. When all movable singularities are poles, the system is said to have the Painleve property. The solutions may be multivalued but they can be analytically continued to meromorphic functions on the universal cover of the punctured Riemann sphere (the punctures being the fixed singularities) and the spectral curve is

  13. Cerebrospinal fluid and plasma cytokines after subarachnoid haemorrhage: CSF interleukin-6 may be an early marker of infection

    Directory of Open Access Journals (Sweden)

    Hopkins Stephen J

    2012-11-01

    Full Text Available Abstract Background Cytokines and cytokine receptor concentrations increase in plasma and cerebrospinal fluid (CSF of patients following subarachnoid haemorrhage (SAH. The relationship between plasma and CSF cytokines, and factors affecting this, are not clear. Methods To help define the relationship, paired plasma and cerebrospinal fluid (CSF samples were collected from patients subject to ventriculostomy. Concentrations of key inflammatory cytokines, interleukin (IL-1ß, IL-1 receptor antagonist (IL-1Ra, IL-1 receptor 2, IL-6, IL-8, IL-10, tumour necrosis factor (TNF-α, and TNF receptors (TNF-R 1 and 2 were determined by immunoassay of CSF and plasma from 21 patients, where samples were available at three or more time points. Results Plasma concentrations of IL-1ß, IL-1Ra, IL-10, TNF-α and TNF-R1 were similar to those in CSF. Plasma TNF-R2 and IL-1R2 concentrations were higher than in CSF. Concentrations of IL-8 and IL-6 in CSF were approximately10 to 1,000-fold higher than in plasma. There was a weak correlation between CSF and plasma IL-8 concentrations (r = 0.26, but no correlation for IL-6. Differences between the central and peripheral pattern of IL-6 were associated with episodes of ventriculostomy-related infection (VRI. A VRI was associated with CSF IL-6 >10,000 pg/mL (P = 0.0002, although peripheral infection was not significantly associated with plasma IL-6. Conclusions These data suggest that plasma cytokine concentrations cannot be used to identify relative changes in the CSF, but that measurement of CSF IL-6 could provide a useful marker of VRI.

  14. Structural insight into the unique properties of adeno-associated virus serotype 9.

    Science.gov (United States)

    DiMattia, Michael A; Nam, Hyun-Joo; Van Vliet, Kim; Mitchell, Matthew; Bennett, Antonette; Gurda, Brittney L; McKenna, Robert; Olson, Norman H; Sinkovits, Robert S; Potter, Mark; Byrne, Barry J; Aslanidi, George; Zolotukhin, Sergei; Muzyczka, Nicholas; Baker, Timothy S; Agbandje-McKenna, Mavis

    2012-06-01

    Adeno-associated virus serotype 9 (AAV9) has enhanced capsid-associated tropism for cardiac muscle and the ability to cross the blood-brain barrier compared to other AAV serotypes. To help identify the structural features facilitating these properties, we have used cryo-electron microscopy (cryo-EM) and three-dimensional image reconstruction (cryo-reconstruction) and X-ray crystallography to determine the structure of the AAV9 capsid at 9.7- and 2.8-Å resolutions, respectively. The AAV9 capsid exhibits the surface topology conserved in all AAVs: depressions at each icosahedral two-fold symmetry axis and surrounding each five-fold axis, three separate protrusions surrounding each three-fold axis, and a channel at each five-fold axis. The AAV9 viral protein (VP) has a conserved core structure, consisting of an eight-stranded, β-barrel motif and the αA helix, which are present in all parvovirus structures. The AAV9 VP differs in nine variable surface regions (VR-I to -IX) compared to AAV4, but at only three (VR-I, VR-II, and VR-IV) compared to AAV2 and AAV8. VR-I differences modify the raised region of the capsid surface between the two-fold and five-fold depressions. The VR-IV difference produces smaller three-fold protrusions in AAV9 that are less "pointed" than AAV2 and AAV8. Significantly, residues in the AAV9 VRs have been identified as important determinants of cellular tropism and transduction and dictate its antigenic diversity from AAV2. Hence, the AAV9 VRs likely confer the unique infection phenotypes of this serotype.

  15. On the origins of the Mendelian laws.

    Science.gov (United States)

    Monaghan, F; Corcos, A

    1984-01-01

    The two laws usually attributed to Mendel were not considered as laws by him. The first law, the law of independent segregation occurs in Mendel's paper as an assumption or hypothesis. Hugo de Vries refers to this as a law discovered by Mendel. This appears to be the first use of an expression equivalent to Mendel's law. In his paper de Vries did not associate the observable characters with structures having a causitive role. That was done by Correns, who transformed the law of segregation of characters into a law of the segregation of anlagen. The second law, the law of independent assortment, is present in embryonic form in Mendel's paper. Here the independent assortment of characters appears as a secondary conclusion to a series of experiments involving several pairs of traits. Mendel repeats the primary conclusion later in the paper but not the secondary one. This leads us to believe that he considered the secondary conclusion as of lesser importance. We note in this context that the 9:3:3:1 ratio commonly associated with the idea of independent assortment, and attributed to Mendel, also does not occur in his paper. A careful reading of the papers of his discoverers shows it was Correns who first drew attention to this ratio. However, he did not formulate the second Mendelian law even though it was clearly implied. Neither was it stated by de Vries. Indeed, the first clear separation of the two laws and the naming of the second law was by T. H. Morgan some 13 years later.

  16. В Кадриорге расскажут о русском Рафаэле

    Index Scriptorium Estoniae

    2011-01-01

    Kadrioru Kunstimuuseumi juubelinäitusel "Šedöövri sünd" eksponeeritakse vene kunstniku Aleksei Jegorovi (1776-1851) prohvet Eliisa imetegu kujutavat maali. Näitusega kaasnevas "Laupäevaakadeemia" loengusarjas on 9. aprillil Aleksandra Murre loeng "Забытый «русский Рафаэль» – Алексей Егоров", ringkäik näitusel

  17. Modulating functions method for parameters estimation in the fifth order KdV equation

    KAUST Repository

    Asiri, Sharefa M.

    2017-07-25

    In this work, the modulating functions method is proposed for estimating coefficients in higher-order nonlinear partial differential equation which is the fifth order Kortewegde Vries (KdV) equation. The proposed method transforms the problem into a system of linear algebraic equations of the unknowns. The statistical properties of the modulating functions solution are described in this paper. In addition, guidelines for choosing the number of modulating functions, which is an important design parameter, are provided. The effectiveness and robustness of the proposed method are shown through numerical simulations in both noise-free and noisy cases.

  18. Anomalous Eclipses of the Young Star RW Aur A

    Science.gov (United States)

    Lamzin, S.; Cheryasov, D.; Chuntonov, G.; Dodin, A.; Grankin, K.; Malanchev, K.; Nadzhip, A.; Safonov, B.; Shakhovskoy, D.; Shenavrin, V.; Tatarnikov, A.; Vozyakova, O.

    2017-06-01

    Results of UBVRIJHKLM photometry, VRI polarimetry and optical spectroscopy of a young star RW Aur A obtained during 2010-11 and 2014-16 dimming events are presented. During the second dimming the star decreased its brightness to ΔV >4.5 mag, polarization of its light in I-band was up to 30 %, and color-magnitude diagramm was similar to that of UX Ori type stars. We conclude that the reason of both dimmings is an eclipses of the star by dust screen, but the size of the screen is much larger than in the case of UXORs.

  19. Browse Author Index

    African Journals Online (AJOL)

    Items 51 - 100 of 276 ... A B C D E F G H I J K L M N O P Q R S T U V W X Y Z All. C. Clark, NC · Clausen, T · Cottrell-Boyce, J. D. Dachew, Berihun assefa · Dada, MU · Dajoh, L · Davids, A · Døving, MH · de Bruijin, A · de Klerk, V · de Vries, M · Derrick, S · Deveau, CS · Dochalson, E · Donovan, Dennis M. Duffett, Lynda · Dumbili ...

  20. Clonación y caracterización de una hidrofobina de clase II (CaHPB) de Candida albicans

    OpenAIRE

    Pedrós Marí, Beatriz

    2003-01-01

    RESUMEN Las hidrofobinas son una familia de proteínas fúngicas hidrofóbicas de secreción, de pequeño tamaño molecular, que exhiben capacidad para autoensamblarse y para unirse a una interfase hidrofílica/hidrofóbica formando una película anfipática (Wessels, 1997). Son proteínas que se dan exclusivamente en hongos miceliares, se caracterizan por presentar ocho residuos de cisteína conservados en sus secuencias (Wessels, 1994, 1997) que forman puentes disulfuro intramoleculares (De Vries et...

  1. Report of Findings: Lake Superior Classified Barrel Disposal Site. Defense Environmental Restoration Program for Formerly Used Defense Sites. Project No. E05MN025501

    Science.gov (United States)

    1991-08-01

    W6 speim f n bea. f l mstyofWhum rauge ismu m we by lb U.S. S"pnr by lb a sw~t~ami ArM Cerps d omersu wif lb p"s Sm am tdo MILu V"t "m Glum met lb...Tw TING AM RUIGU UGifi, rm- M At0-- - tow MIlU im- Vri ad.~J tLa un rn -|- - -I T - , a I s u m u O Fe

  2. Teneurs azotée et minérale des espèces fourragères dominantes et ...

    African Journals Online (AJOL)

    SARAH

    31 mars 2016 ... par la méthode d'échantillonnage des poignées de De Vries (1948). La teneur en matières azotées a été déterminée par la méthode de Kjeldahl et les minéraux par .... digesteur muni d'une pompe pour neutraliser les fumées toxiques. Une solution de sulfate d'ammonium est obtenue. La seconde étape a ...

  3. [Doubts about the efficacy of fall-prevention programmes for the elderly].

    Science.gov (United States)

    Pijpers, Evelien; Mulder, Wubbo J

    2010-01-01

    Multifactorial fall-prevention programmes are often not effective in preventing falls and functional decline. This is also the case in the recently published study of de Vries et al. Several causes for this lack of efficacy can be given. An important finding in the Dutch population is that a pragmatic multidisciplinary fall-prevention programme has no added benefit over and above normal care. This is probably because in the Dutch situation, the GP has already adapted many aspects of multifactorial fall analysis into the integrated care he or she provides to the elderly patient.

  4. Flux and color variations of the quadruply imaged quasar HE 0435-1223

    DEFF Research Database (Denmark)

    Ricci, D.; Poels, J.; Elyiv, A.

    2011-01-01

    Aims: We present VRi photometric observations of the quadruply imaged quasarHE0435-1223, carried out with the Danish 1.54 m telescope at the La Silla Observatory. Our aim was to monitor and study the magnitudes and colors of each lensed component as a function of time. Methods. We monitored...... lensed components in the three filters. We also found a significant increase (≈ 0.05-0.015) in their V - R and R - i color indices. Conclusions. These flux and color variations are very likely caused by intrinsic variations of the quasar between the observed epochs. Microlensing effects probably also...

  5. Gilles Coignet. A migrant painter from Antwerp and his Hamburg career

    OpenAIRE

    Barbara Uppenkamp

    2015-01-01

    The painter Gilles Coignet was born in Antwerp c. 1542 to a family of artists and scientists. He spent some time in Italy and, as a Lutheran Protestant, fled from Antwerp to Amsterdam in 1585. He lived in Hamburg since 1595, where he died in December 1599. Here he had contact with other Netherlandish artists. Van Mander reports that it was Coignet who advised Vredeman de Vries to move from Hamburg to Amsterdam in 1598. This contribution focuses on Coignet’s last years and sheds new light on t...

  6. Gilles Coignet. A migrant painter from Antwerp and his Hamburg career

    Directory of Open Access Journals (Sweden)

    Barbara Uppenkamp

    2015-12-01

    Full Text Available The painter Gilles Coignet was born in Antwerp c. 1542 to a family of artists and scientists. He spent some time in Italy and, as a Lutheran Protestant, fled from Antwerp to Amsterdam in 1585. He lived in Hamburg since 1595, where he died in December 1599. Here he had contact with other Netherlandish artists. Van Mander reports that it was Coignet who advised Vredeman de Vries to move from Hamburg to Amsterdam in 1598. This contribution focuses on Coignet’s last years and sheds new light on the professional and social networks of exiled Netherlandish artists in Hamburg.

  7. Nonlinear Spectroscopy.

    Science.gov (United States)

    1985-03-20

    and R.G. Brewer. Generali:ed two photon theory 459 The open parameter v appears in the tuning parameters which are of the form At= (1i + J, -Wi (i = 1...appears as an open parameter through the relation l, = fl’ + kv. Varying v from - 0 to + 00 means that we move all the vertical asymptotes together from...Engineers 11.3, 42 (1977); H. de Vries, P. de Bree and D. A. Wiersma , Chem. Phys. Let:. 52, 399 (1977). 3. R. M. Macfarlane, A. Z. Genack and R. G. Brewer

  8. Flux and color variations of the doubly imaged quasar UM673

    DEFF Research Database (Denmark)

    Ricci, D.; Elyiv, A.; Finet, F.

    2013-01-01

    Aims. With the aim of characterizing the flux and color variations of the multiple components of the gravitationally lensed quasar UM673 as a function of time, we have performed multiepoch and multiband photometric observations with the Danish telescope at the La Silla Observatory. Methods...... seasons (+ 0.09/+ 0.11/+ 0.05 mag) and a subsequent increase during the following ones (- 0.11/- 0.11/- 0.10 mag) in the V/R/i spectral bands, respectively. Comparing our results with previous studies, we find smaller color variations between these seasons as compared with previous ones. We also separate...

  9. A novel fungal hyperparasite of Puccinia striiformis f. sp. tritici, the causal agent of wheat stripe rust.

    Directory of Open Access Journals (Sweden)

    Gangming Zhan

    Full Text Available Puccinia striiformis f. sp. tritici (Pst, the causal fungus of wheat stripe rust, was previously reported to be infected by Lecanicillium lecanii, Microdochium nivale and Typhula idahoensis. Here, we report a novel hyperparasite on Pst. This hyperparasitic fungus was identified as Cladosporium cladosporioides (Fresen. GA de Vries based on morphological characteristics observed by light and scanning electron microscopy together with molecular data. The hyperparasite reduced the production and viability of urediniospores and, therefore, could potentially be used for biological control of wheat stripe rust.

  10. Modelling transport of chokka squid (Loligo reynaudii) paralarvae off South Africa: reviewing, testing and extending the ‘Westward Transport Hypothesis'

    CSIR Research Space (South Africa)

    Martins, RS

    2013-08-01

    Full Text Available and recovery experiments carried out with 15 d old Doryteuthis opalescens, where paralarvae were found to regain the before-starvation condition if fed after 3 d of food deprivation (Vidal et al., 2006). Newly-hatched chokka squid paralarvae, however, can... migration: zooplankton photobiology and behavior. Oceanogr. Mar. Biol. 26: 361–392 Forward Jr, R.B., De Vries, M.C., Tankersley, R.A., Rittschof, W.F., Hettler, W.F., Burke, J.S., Welch, J.M. and Hoss, D.E. (1999) Behaviour and sensory Page 24 of 38...

  11. Experimental study of nonlinear dust acoustic solitary waves in a dusty plasma

    CERN Document Server

    Bandyopadhyay, P; Sen, A; Kaw, P K

    2008-01-01

    The excitation and propagation of finite amplitude low frequency solitary waves are investigated in an Argon plasma impregnated with kaolin dust particles. A nonlinear longitudinal dust acoustic solitary wave is excited by pulse modulating the discharge voltage with a negative potential. It is found that the velocity of the solitary wave increases and the width decreases with the increase of the modulating voltage, but the product of the solitary wave amplitude and the square of the width remains nearly constant. The experimental findings are compared with analytic soliton solutions of a model Kortweg-de Vries equation.

  12. A new car-following model with two delays

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Lei, E-mail: yuleijk@126.com [College of Automation, Northwestern Polytechnical University, Xi' an, ShaanXi (China); Shi, Zhong-ke [College of Automation, Northwestern Polytechnical University, Xi' an, ShaanXi (China); Li, Tong [Department of Mathematics, University of Iowa, Iowa City, IA (United States)

    2014-01-17

    A new car-following model is proposed by taking into account two different time delays in sensing headway and velocity. The effect of time delays on the stability analysis is studied. The theoretical and numerical results show that traffic jams are suppressed efficiently when the difference between two time delays decreases and those can be described by the solution of the modified Korteweg–de Vries (mKdV) equation. Traffic flow is more stable with two delays in headway and velocity than in the case with only one delay in headway. The impact of local small disturbance to the system is also studied.

  13. An introduction to linear ordinary differential equations using the impulsive response method and factorization

    CERN Document Server

    Camporesi, Roberto

    2016-01-01

    This book presents a method for solving linear ordinary differential equations based on the factorization of the differential operator. The approach for the case of constant coefficients is elementary, and only requires a basic knowledge of calculus and linear algebra. In particular, the book avoids the use of distribution theory, as well as the other more advanced approaches: Laplace transform, linear systems, the general theory of linear equations with variable coefficients and variation of parameters. The case of variable coefficients is addressed using Mammana’s result for the factorization of a real linear ordinary differential operator into a product of first-order (complex) factors, as well as a recent generalization of this result to the case of complex-valued coefficients.

  14. Variable separation for time fractional advection-dispersion equation with initial and boundary conditions

    Directory of Open Access Journals (Sweden)

    Zhang Sheng

    2016-01-01

    Full Text Available In this paper, variable separation method combined with the properties of Mittag-Leffler function is used to solve a variable-coefficient time fractional advection-dispersion equation with initial and boundary conditions. As a result, a explicit exact solution is obtained. It is shown that the variable separation method can provide a useful mathematical tool for solving the time fractional heat transfer equations.

  15. Asymptotics of eigenfunctions for Sturm-Liouville problem in difference equations

    Science.gov (United States)

    Bas, Erdal; Ozarslan, Ramazan

    2016-06-01

    In this study, Sturm-Liouville problem with variable coefficient, potential function q (n), for difference equation is considered. The representation of solutions is obtained by variation of parameters method for two different initial value problems and trigonometric solutions are found by means of complex characteristic roots. It is proved that these results hold the equation by using summation by parts method. Two estimations of asymptotic expansion of the solutions are established.

  16. Evolution of bulk strain solitons in cylindrical inhomogeneous shells

    Energy Technology Data Exchange (ETDEWEB)

    Shvartz, A., E-mail: andrew.shvartz@mail.ioffe.ru; Samsonov, A.; Dreiden, G.; Semenova, I. [Ioffe Institute, 26 Politekhnicheskaya, St Petersburg 194021 (Russian Federation)

    2015-10-28

    Bulk strain solitary waves in nonlinearly elastic thin-walled cylindrical shells with variable geometrical and physical parameters are studied, and equation for the longitudinal strain component with the variable coefficients is derived. A conservative finite difference scheme is proposed, and the results of numerical simulation of the strain soliton evolution in a shell with the abrupt variations of cross section and physical properties of the material are presented.

  17. Application of Sinc-Galerkin Method for Solving Space-Fractional Boundary Value Problems

    Directory of Open Access Journals (Sweden)

    Sertan Alkan

    2015-01-01

    Full Text Available We employ the sinc-Galerkin method to obtain approximate solutions of space-fractional order partial differential equations (FPDEs with variable coefficients. The fractional derivatives are used in the Caputo sense. The method is applied to three different problems and the obtained solutions are compared with the exact solutions of the problems. These comparisons demonstrate that the sinc-Galerkin method is a very efficient tool in solving space-fractional partial differential equations.

  18. Solution of Moving Boundary Space-Time Fractional Burger’s Equation

    Directory of Open Access Journals (Sweden)

    E. A.-B. Abdel-Salam

    2014-01-01

    Full Text Available The fractional Riccati expansion method is used to solve fractional differential equations with variable coefficients. To illustrate the effectiveness of the method, the moving boundary space-time fractional Burger’s equation is studied. The obtained solutions include generalized trigonometric and hyperbolic function solutions. Among these solutions, some are found for the first time. The linear and periodic moving boundaries for the kink solution of the Burger’s equation are presented graphically and discussed.

  19. Differential operators in exterior domain and application

    OpenAIRE

    Shakhmurov, Veli

    2017-01-01

    The abstract elliptic and parabolic equations on exterior domain are considered. The equations have top-order variable coefficients. The separability properties of boundary value problems for elliptic equation and well-posedness of the Cauchy problem for parabolic equations are established. In application, the well-posedness of Wentzell-Robin type mixed probem for parabolic equation, Cauchy problem for anisotropic parabolic equations and system of parabolic equations are derived

  20. Solution of elliptic partial differential equations by fast Poisson solvers using a local relaxation factor. 2: Two-step method

    Science.gov (United States)

    Chang, S. C.

    1986-01-01

    A two-step semidirect procedure is developed to accelerate the one-step procedure described in NASA TP-2529. For a set of constant coefficient model problems, the acceleration factor increases from 1 to 2 as the one-step procedure convergence rate decreases from + infinity to 0. It is also shown numerically that the two-step procedure can substantially accelerate the convergence of the numerical solution of many partial differential equations (PDE's) with variable coefficients.