Fourth Order Theories Without Ghosts
Mannheim, P D; Mannheim, Philip D.; Davidson, Aharon
2000-01-01
Using the Dirac constraint method we show that the pure fourth-order Pais-Uhlenbeck oscillator model is free of observable negative norm states. Even though such ghosts do appear when the fourth order theory is coupled to a second order one, the limit in which the second order action is switched off is found to be a highly singular one in which these states move off shell. Given this result, construction of a fully unitary, renormalizable, gravitational theory based on a purely fourth order action in 4 dimensions now appears feasible.
Fourth order deformed general relativity
Cuttell, Peter D
2014-01-01
Whenever the condition of anomaly freedom is imposed within the framework of effective approaches to loop quantum cosmology, one seems to conclude that a deformation of general covariance is required. Here, starting from a general deformation we regain an effective gravitational Lagrangian including terms up to fourth order in extrinsic curvature. We subsequently constrain the form of the corrections, and then investigate the conditions for the occurrence of a big bounce and the realisation of an inflationary era, in the presence of a perfect fluid or scalar field.
JACOBI PSEUDOSPECTRAL METHOD FOR FOURTH ORDER PROBLEMS
Institute of Scientific and Technical Information of China (English)
Zheng-su Wan; Ben-yu Guo; Zhong-qing Wang
2006-01-01
In this paper, we investigate Jacobi pseudospectral method for fourth order problems.We establish some basic results on the Jacobi-Gauss-type interpolations in non-uniformly weighted Sobolev spaces, which serve as important tools in analysis of numerical quadratures, and numerical methods of differential and integral equations. Then we propose Jacobi pseudospectral schemes for several singular problems and multiple-dimensional problems of fourth order. Numerical results demonstrate the spectral accuracy of these schemes,and coincide well with theoretical analysis.
Fourth order difference methods for hyperbolic IBVP's
Gustafsson, Bertil; Olsson, Pelle
1994-01-01
Fourth order difference approximations of initial-boundary value problems for hyperbolic partial differential equations are considered. We use the method of lines approach with both explicit and compact implicit difference operators in space. The explicit operator satisfies an energy estimate leading to strict stability. For the implicit operator we develop boundary conditions and give a complete proof of strong stability using the Laplace transform technique. We also present numerical experiments for the linear advection equation and Burgers' equation with discontinuities in the solution or in its derivative. The first equation is used for modeling contact discontinuities in fluid dynamics, the second one for modeling shocks and rarefaction waves. The time discretization is done with a third order Runge-Kutta TVD method. For solutions with discontinuities in the solution itself we add a filter based on second order viscosity. In case of the non-linear Burger's equation we use a flux splitting technique that results in an energy estimate for certain different approximations, in which case also an entropy condition is fulfilled. In particular we shall demonstrate that the unsplit conservative form produces a non-physical shock instead of the physically correct rarefaction wave. In the numerical experiments we compare our fourth order methods with a standard second order one and with a third order TVD-method. The results show that the fourth order methods are the only ones that give good results for all the considered test problems.
On a fourth order superlinear elliptic problem
Directory of Open Access Journals (Sweden)
M. Ramos
2001-01-01
Full Text Available We prove the existence of a nonzero solution for the fourth order elliptic equation $$Delta^2u= mu u +a(xg(u$$ with boundary conditions $u=Delta u=0$. Here, $mu$ is a real parameter, $g$ is superlinear both at zero and infinity and $a(x$ changes sign in $Omega$. The proof uses a variational argument based on the argument by Bahri-Lions cite{BL}.
Fourth-order partial differential equations for effective image denoising
Directory of Open Access Journals (Sweden)
Seongjai Kim
2009-04-01
Full Text Available This article concerns mathematical image denoising methods incorporating fourth-order partial differential equations (PDEs. We introduce and analyze piecewise planarity conditions (PPCs with which unconstrained fourth-order variational models in continuum converge to a piecewise planar image. It has been observed that fourth-order variational models holding PPCs can restore better images than models without PPCs and second-order models. Numerical schemes are presented in detail and various examples in image denoising are provided to verify the claim.
Two New Fourth-Order Three-Stage Symplectic Integrators
Institute of Scientific and Technical Information of China (English)
LI Rong; WU Xin
2011-01-01
Two new fourth-order three-stage symplectic integrators are specifically designed for a family of Hamiltonian systems,such as the harmonic oscillator,mathematical pendulum and lattice ψ4 model.When the nonintegrable lattice ψ4 system is taken as a test model,numerical comparisons show that the new methods have a great advantage over the second-order Verlet symplectic integrators in the accuracy of energy,become explicitly better than the usual non-gradient fourth-order seven-stage symplectic integrator of Forest and Ruth,and are almost equivalent to a fourth-order seven-stage force gradient symplectic integrator of Chin.As the most important advantage,the new integrators are convenient for solving the variational equations of many Hamiltonian systems so as to save a great deal of the computational cost when scanning a lot of orbits for chaos.
Fourth-order acoustic torque in intense sound fields
Wang, T. G.; Kanber, H.; Olli, E. E.
1978-01-01
The observation of a fourth-order acoustic torque in intense sound fields is reported. The torque was determined by measuring the acoustically induced angular deflection of a polished cylinder suspended by a torsion fiber. This torque was measured in a sound field of amplitude greater than that in which first-order acoustic torque has been observed.
Solution to the ghost problem in fourth order derivative theories
Mannheim, P D
2006-01-01
We present a solution to the ghost problem in fourth order derivative theories. In particular we study the Pais-Uhlenbeck fourth order oscillator model, a model which serves as a prototype for theories which are based on second plus fourth order derivative actions. Via a Dirac constraint method quantization we construct the appropriate quantum-mechanical Hamiltonian and Hilbert space for the system. We find that while the second-quantized Fock space of the general Pais-Uhlenbeck model does indeed contain the negative norm energy eigenstates which are characteristic of higher derivative theories, in the limit in which we switch off the second order action, such ghost states are found to move off shell, with the spectrum of asymptotic in and out S-matrix states of the pure fourth order theory which results being found to be completely devoid of states with either negative energy or negative norm. We provide additional insight into the structure of the Pais-Uhlenbeck theory by quantizing it via path integration ...
Multiway Filtering Based on Fourth-Order Cumulants
Directory of Open Access Journals (Sweden)
Salah Bourennane
2005-05-01
Full Text Available We propose a new multiway filtering based on fourth-order cumulants for the denoising of noisy data tensor with correlated Gaussian noise. The classical multiway filtering is based on the TUCKALS3 algorithm that computes a lower-rank tensor approximation. The presented method relies on the statistics of the analyzed multicomponent signal. We first recall how the well-known lower rank-(K1,Ã¢Â€Â¦,KN tensor approximation processed by TUCKALS3 alternating least square algorithm exploits second-order statistics. Then, we propose to introduce the fourth-order statistics in the TUCKALS3-based method. Indeed, the use of fourth-order cumulants enables to remove the Gaussian components of an additive noise. In the presented method the estimation of the n-mode projector on the n-mode signal subspace are built from the eigenvectors associated with the largest eigenvalues of a fourth-order cumulant slice matrix instead of a covariance matrix. Each projector is applied by means of the n-mode product operator on the n-mode of the data tensor. The qualitative results of the improved multiway TUCKALS3-based filterings are shown for the case of noise reduction in a color image and multicomponent seismic data.
Estimation of the fourth-order dispersion coefficient β4
Institute of Scientific and Technical Information of China (English)
Jing Huang; Jianquan Yao
2012-01-01
The fourth-order dispersion coefficient of fibers are estimated by the iterations around the third-order dispersion and the high-order nonlinear items in the nonlinear Schordinger equation solved by Green's function approach.Our theoretical evaluation demonstrates that the fourth-order dispersion coefficient slightly varies with distance.The fibers also record β4 values of about 0.002,0.003,and 0.00032 ps4/km for SMF,NZDSF and DCF,respectively.In the zero-dispersion regime,the high-order nonlinear effect (higher than self-steepening) has a strong impact on the transmitted short pulse.This red-shifts accelerates the symmetrical split of the pulse,although this effect is degraded rapidly with the increase of β2.Thus,the contributions to β4 of SMF,NZDSF,and DCF can be neglected.
A curve flow evolved by a fourth order parabolic equation
Institute of Scientific and Technical Information of China (English)
无
2009-01-01
We study a fourth order curve flow, which is the gradient flow of a functional describing the shapes of human red blood cells. We prove that for any smooth closed initial curve in R2, the flow has a smooth solution for all time and the solution subconverges to a critical point of the functional.
A curve flow evolved by a fourth order parabolic equation
Institute of Scientific and Technical Information of China (English)
LIU YanNan; JIAN HuaiYu
2009-01-01
We study a fourth order curve flow,which is the gradient flow of a functional describing the shapes of human red blood cells.We prove that for any smooth closed initial curve in R2,the flow has a smooth solution for all time and the solution subconverges to a critical point of the functional.
The Weak Field Limit of Fourth Order Gravity
Capozziello, Salvatore
2010-01-01
We discuss Newtonian and the post-Newtonian limits of Fourth Order Gravity Theories pointing out, in details, their resemblances and differences with respect to General Relativity. Particular emphasis is placed on the exact solutions and methods used to obtain them.
Fourth-order discrete anisotropic boundary-value problems
Directory of Open Access Journals (Sweden)
Maciej Leszczynski
2015-09-01
Full Text Available In this article we consider the fourth-order discrete anisotropic boundary value problem with both advance and retardation. We apply the direct method of the calculus of variations and the mountain pass technique to prove the existence of at least one and at least two solutions. Non-existence of non-trivial solutions is also undertaken.
The Weak Field Limit of Fourth Order Gravity
Capozziello, Salvatore; Stabile, Arturo
2010-01-01
We discuss Newtonian and the post-Newtonian limits of Fourth Order Gravity Theories pointing out, in details, their resemblances and differences with respect to General Relativity. Particular emphasis is placed on the exact solutions and methods used to obtain them.
Null controllability for a fourth order parabolic equation
Institute of Scientific and Technical Information of China (English)
YU Hang
2009-01-01
In the paper,the null interior controllability for a fourth order parabolic equation is obtained.The method Is based on Lebeau-Rabbiano inequality which is a quantitative unique continuation property for the sum of eigenfunctions of the Laplacian.
Fourth-order discrete anisotropic boundary-value problems
2015-01-01
In this article we consider the fourth-order discrete anisotropic boundary value problem with both advance and retardation. We apply the direct method of the calculus of variations and the mountain pass technique to prove the existence of at least one and at least two solutions. Non-existence of non-trivial solutions is also undertaken.
POSITIVE SOLUTIONS TO FOURTH-ORDER NEUMANN BOUNDARY VALUE PROBLEM
Institute of Scientific and Technical Information of China (English)
无
2010-01-01
In this paper, we study a class of fourth-order Neumann boundary value problem (NBVP for short). By virtue of fixed point index and the spectral theory of linear operators, the existence of positive solutions is obtained under the assumption that the nonlinearity satisfies sublinear or superlinear conditions, which are relevant to the first eigenvalue of the corresponding linear operator.
Fourth-Order Difference Methods for Hyperbolic IBVPs
Gustafsson, Bertil; Olsson, Pelle
1995-03-01
In this paper we consider fourth-order difference approximations of initial-boundary value problems for hyperbolic partial differential equations. We use the method of lines approach with both explicit and compact implicit difference operators in space. The explicit operator satisfies an energy estimate leading to strict stability. For the implicit operator we develop boundary conditions and give a complete proof of strong stability using the Laplace transform technique. We also present numerical experiments for the linear advection equation and Burgers' equation with discontinuities in the solution or in its derivative. The first equation is used for modeling contact discontinuities in fluid dynamics; the second one is used for modeling shocks and rarefaction waves. The time discretization is done with a third-order Runge-Kutta TVD method. For solutions with discontinuities in the solution itself we add a filter based on second-order viscosity. In case of the non-linear Burgers' equation we use a flux splitting technique that results in an energy estimate for certain difference approximations, in which case also an entropy condition is fulfilled. In particular we shall demonstrate that the unsplit conservative form produces a non-physical shock instead of the physically correct rarefaction wave. In the numerical experiments we compare our fourth-order methods with a standard second-order one and with a third-order TVD method. The results show that the fourth-order methods are the only ones that give good results for all the considered test problems.
New Efficient Fourth Order Method for Solving Nonlinear Equations
Directory of Open Access Journals (Sweden)
Farooq Ahmad
2013-12-01
Full Text Available In a paper [Appl. Math. Comput., 188 (2 (2007 1587--1591], authors have suggested and analyzed a method for solving nonlinear equations. In the present work, we modified this method by using the finite difference scheme, which has a quintic convergence. We have compared this modified Halley method with some other iterative of fifth-orders convergence methods, which shows that this new method having convergence of fourth order, is efficient.
Fourth-order gravity gradient torque of spacecraft orbiting asteroids
Wang, Yue; Xu, Shijie
2014-01-01
The dynamical behavior of spacecraft around asteroids is a key element in design of such missions. An asteroid's irregular shape, non-spherical mass distribution and its rotational sate make the dynamics of spacecraft quite complex. This paper focuses on the gravity gradient torque of spacecraft around non-spherical asteroids. The gravity field of the asteroid is approximated as a 2nd degree and order-gravity field with harmonic coefficients C20 and C22. By introducing the spacecraft's higher-order inertia integrals, a full fourth-order gravity gradient torque model of the spacecraft is established through the gravitational potential derivatives. Our full fourth-order model is more precise than previous fourth-order model due to the consideration of higher-order inertia integrals of the spacecraft. Some interesting conclusions about the gravity gradient torque model are reached. Then a numerical simulation is carried out to verify our model. In the numerical simulation, a special spacecraft consisted of 36 po...
Fourth order phase-field model for local max-ent approximants applied to crack propagation
Amiri, Fatemeh; Millán, Daniel; Arroyo Balaguer, Marino; Silani, Mohammad; Rabczuk, Timon
2016-01-01
We apply a fourth order phase-field model for fracture based on local maximum entropy (LME) approximants. The higher order continuity of the meshfree LME approximants allows to directly solve the fourth order phase-field equations without splitting the fourth order differential equation into two second order differential equations. We will first show that the crack surface can be captured more accurately in the fourth order model. Furthermore, less nodes are needed for the fourth order model ...
Nodal Solutions for a Nonlinear Fourth-Order Eigenvalue Problem
Institute of Scientific and Technical Information of China (English)
Ru Yun MA; Bevan THOMPSON
2008-01-01
We are concerned with determining the values of λ, for which there exist nodal solutions of the fourth-order boundary value problem y =λa(x)f(y),00 for all u ≠0. We give conditions on the ratio f (s)/s,at infinity and zero, that guarantee the existence of nodal solutions.The proof of our main results is based upon bifurcation techniques.
Fourth order wave equations with nonlinear strain and source terms
Liu, Yacheng; Xu, Runzhang
2007-07-01
In this paper we study the initial boundary value problem for fourth order wave equations with nonlinear strain and source terms. First we introduce a family of potential wells and prove the invariance of some sets and vacuum isolating of solutions. Then we obtain a threshold result of global existence and nonexistence. Finally we discuss the global existence of solutions for the problem with critical initial condition I(u0)[greater-or-equal, slanted]0, E(0)=d. So the Esquivel-Avila's results are generalized and improved.
Cosmic Acceleration in a Model of Fourth Order Gravity
Banerjee, Shreya; Singh, Tejinder P
2015-01-01
We investigate a fourth order model of gravity, having a free length parameter, and no cosmological constant or dark energy. We consider cosmological evolution of a flat Friedmann universe in this model for the case that the length parameter is of the order of present Hubble radius. By making a suitable choice for the present value of the Hubble parameter, and value of third derivative of the scale factor (the jerk) we find that the model can explain cosmic acceleration to the same degree of accuracy as the standard concordance model. If the free length parameter is assumed to be time-dependent, and of the order of the Hubble parameter of the corresponding epoch, the model can still explain cosmic acceleration, and provides a possible resolution of the cosmic coincidence problem. We also compare redshift drift in this model, with that in the standard model.
Black hole shadows in fourth-order conformal Weyl gravity
Mureika, Jonas R
2016-01-01
We calculate the characteristics of the "black hole shadow" for a rotating, neutral black hole in fourth-order conformal Weyl gravity. It is shown that the morphology is not significantly affected by the underlying framework, except for very large masses. Conformal gravity black hole shadows would also significantly differ from their general relativistic counterparts if the values of the main conformal gravity parameters, $\\gamma$ and $\\kappa$, were increased by several orders of magnitude. Such increased values for $\\gamma$ and $\\kappa$ are currently ruled out by gravitational phenomenology. Therefore, it is unlikely that these differences in black hole shadows will be detected in future observations, carried out by the Event Horizon Telescope or others such experiments.
Wormhole geometries in fourth-order conformal Weyl gravity
Varieschi, Gabriele U
2015-01-01
We present an analysis of the classic wormhole geometries based on conformal Weyl gravity, rather than standard general relativity. The main characteristics of the resulting traversable wormholes remain the same as in the seminal study by Morris and Thorne, namely, that effective super-luminal motion is a viable consequence of the metric. Improving on previous work on the subject, we show that for particular choices of the shape and redshift functions, the wormhole metric in the context of conformal gravity does not violate the main energy conditions, as was the case of the original solutions. In particular, the resulting geometry does not require the use of exotic matter at or near the wormhole throat. Therefore, if fourth-order conformal Weyl gravity is a correct extension of general relativity, traversable wormholes might become a realistic solution for interstellar travel.
Wormhole geometries in fourth-order conformal Weyl gravity
Varieschi, Gabriele U.; Ault, Kellie L.
2016-04-01
We present an analysis of the classic wormhole geometries based on conformal Weyl gravity, rather than standard general relativity. The main characteristics of the resulting traversable wormholes remains the same as in the seminal study by Morris and Thorne, namely, that effective super-luminal motion is a viable consequence of the metric. Improving on previous work on the subject, we show that for particular choices of the shape and redshift functions the wormhole metric in the context of conformal gravity does not violate the main energy conditions at or near the wormhole throat. Some exotic matter might still be needed at the junction between our solutions and flat spacetime, but we demonstrate that the averaged null energy condition (as evaluated along radial null geodesics) is satisfied for a particular set of wormhole geometries. Therefore, if fourth-order conformal Weyl gravity is a correct extension of general relativity, traversable wormholes might become a realistic solution for interstellar travel.
Weak gravitational lensing by fourth order gravity black holes
Horváth, Zsolt; Hobill, David; Capozziello, Salvatore; De Laurentis, Mariafelicia
2012-01-01
We discuss weak lensing characteristics for black holes in a fourth order f(R) gravity theory, characterized by a gravitational strength parameter $\\sigma $ and a distance scale $r_{c}$. Above $r_{c}$ gravity is strengthened and as a consequence weak lensing features are modified compared to the Schwarzschild case. We find a critical impact parameter (depending upon $r_{c}$) for which the behavior of the deflection angle changes. Using the Virbhadra-Ellis lens equation we improve the computation of the image positions, Einstein ring radii, magnification factors and the magnification ratio. We demonstrate that the magnification ratio as function of image separation has a different power-law dependence for each parameter $\\sigma $. As these are the lensing quantities most conveniently determined by direct measurements, future lensing surveys will be able to constrain the parameter $\\sigma $ based on this prediction.
Wavelet-based Image Enhancement Using Fourth Order PDE
DEFF Research Database (Denmark)
Nadernejad, Ehsan; Forchhammer, Søren
2011-01-01
The presence of noise interference signal may cause problems in signal and image analysis; hence signal and image de-noising is often used as a preprocessing stage in many signal processing applications. In this paper, a new method is presented for image de-noising based on fourth order partial...... differential equations (PDEs) and wavelet transform. In the existing wavelet thresholding methods, the final noise reduced image has limited improvement. It is due to keeping the approximate coefficients of the image unchanged. These coefficients have the main information of the image. Since noise affects both...... indicate superiority of the proposed method over the existing waveletbased image de-noising, anisotropic diffusion, and wiener filtering techniques....
Fourth-order partial differential equations for noise removal.
You, Y L; Kaveh, M
2000-01-01
A class of fourth-order partial differential equations (PDEs) are proposed to optimize the trade-off between noise removal and edge preservation. The time evolution of these PDEs seeks to minimize a cost functional which is an increasing function of the absolute value of the Laplacian of the image intensity function. Since the Laplacian of an image at a pixel is zero if the image is planar in its neighborhood, these PDEs attempt to remove noise and preserve edges by approximating an observed image with a piecewise planar image. Piecewise planar images look more natural than step images which anisotropic diffusion (second order PDEs) uses to approximate an observed image. So the proposed PDEs are able to avoid the blocky effects widely seen in images processed by anisotropic diffusion, while achieving the degree of noise removal and edge preservation comparable to anisotropic diffusion. Although both approaches seem to be comparable in removing speckles in the observed images, speckles are more visible in images processed by the proposed PDEs, because piecewise planar images are less likely to mask speckles than step images and anisotropic diffusion tends to generate multiple false edges. Speckles can be easily removed by simple algorithms such as the one presented in this paper.
Scale-invariant scalar spectrum from the nonminimal derivative coupling with fourth-order term
Myung, Yun Soo
2015-01-01
An exactly scale-invariant spectrum of scalar perturbation generated during de Sitter spacetime is found from the gravity model of the nonminimal derivative coupling with fourth-order term. The nonminimal derivative coupling term generates a healthy (ghost-free) fourth-order derivative term, while the fourth-order term provides an unhealthy (ghost) fourth-order derivative term. The Harrison-Zel'dovich spectrum obtained from Fourier transforming the fourth-order propagator in de Sitter space is recovered by computing the power spectrum in its momentum space directly. It shows that this model provides a truly scale-invariant spectrum, in addition to the Lee-Wick scalar theory.
PPN-limit of Fourth Order Gravity inspired by Scalar-Tensor Gravity
Capozziello, S.; Troisi, A
2005-01-01
Based on the {\\it dynamical} equivalence between higher order gravity and scalar-tensor gravity the PPN-limit of fourth order gravity is discussed. We exploit this analogy developing a fourth order gravity version of the Eddington PPN-parameters. As a result, Solar System experiments can be reconciled with higher order gravity, if physical constraints descending from experiments are fulfilled.
PPN-limit of Fourth Order Gravity inspired by Scalar-Tensor Gravity
Capozziello, S.; Troisi, A.
2005-01-01
Based on the {\\it dynamical} equivalence between higher order gravity and scalar-tensor gravity the PPN-limit of fourth order gravity is discussed. We exploit this analogy developing a fourth order gravity version of the Eddington PPN-parameters. As a result, Solar System experiments can be reconciled with higher order gravity, if physical constraints descending from experiments are fulfilled.
Ghost-free, finite, fourth-order D = 3 gravity.
Deser, S
2009-09-04
Canonical analysis of a recently proposed linear + quadratic curvature gravity model in D = 3 establishes its pure, irreducibly fourth derivative, quadratic curvature limit as both ghost-free and power-counting UV finite, thereby maximally violating standard folklore. This limit is representative of a generic class whose kinetic terms are conformally invariant in any dimension, but it is unique in simultaneously avoiding the transverse-traceless graviton ghosts plaguing D > 3 quadratic actions as well as double pole propagators in its other variables. While the two-term model is also unitary, its additional mode's second-derivative nature forfeits finiteness.
ON THE INSTABILITY OF SOLUTIONS TO A NONLINEAR VECTOR DIFFERENTIAL EQUATION OF FOURTH ORDER
Institute of Scientific and Technical Information of China (English)
无
2011-01-01
This paper presents a new result related to the instability of the zero solution to a nonlinear vector differential equation of fourth order.Our result includes and improves an instability result in the previous literature,which is related to the instability of the zero solution to a nonlinear scalar differential equation of fourth order.
A Note on Four-Dimensional Symmetry Algebras and Fourth-Order Ordinary Differential Equations
Directory of Open Access Journals (Sweden)
A. Fatima
2013-01-01
Full Text Available We provide a supplementation of the results on the canonical forms for scalar fourth-order ordinary differential equations (ODEs which admit four-dimensional Lie algebras obtained recently. Together with these new canonical forms, a complete list of scalar fourth-order ODEs that admit four-dimensional Lie algebras is available.
Kurt, Arzu; Eryigit, Resul
2015-12-01
The master equation for a charged harmonic oscillator coupled to an electromagnetic reservoir is investigated up to fourth order in the interaction strength by using Krylov averaging method. The interaction is in the velocity-coupling form and includes a diamagnetic term. Exact analytical expressions for the second-, the third-, and the fourth-order contributions to mass renormalization, decay constant, normal and anomalous diffusion coefficients are obtained for the blackbody type environment. It is found that, generally, the third- and the fourth-order contributions have opposite signs when their magnitudes are comparable to that of the second-order one.
STABLE FOURTH-ORDER STREAM-FUNCTION METHODS FOR INCOMPRESSIBLE FLOWS WITH BOUNDARIES
Institute of Scientific and Technical Information of China (English)
Thomas Y. Hou; Brian R. Wetton
2009-01-01
Fourth-order stream-function methods are proposed for the time dependent, incom-pressible Navier-Stokes and Bonssinesq equations. Wide difference stencils are used instead of compact ones and the boundary terms are handled by extrapolating the stream-function values inside the computational domain to grid points outside, up to fourth-order in the no-slip condition. Formal error analysis is done for a simple model problem, showing that this extrapolation introduces numerical boundary layers at fifth-order in the stream-function. The fourth-order convergence in velocity of the proposed method for the full problem is shown numerically.
Fourth-order master equation for a charged harmonic oscillator coupled to an electromagnetic field
Kurt, Arzu; Eryigit, Resul
Using Krylov averaging method, we have derived a fourth-order master equation for a charged harmonic oscillator weakly coupled to an electromagnetic field. Interaction is assumed to be of velocity coupling type which also takes into account the diagmagnetic term. Exact analytical expressions have been obtained for the second, the third and the fourth-order corrections to the diffusion and the drift terms of the master equation. We examined the validity range of the second order master equation in terms of the coupling constant and the bath cutoff frequency and found that for the most values of those parameters, the contribution from the third and the fourth order terms have opposite signs and cancel each other. Inclusion of the third and the fourth-order terms is found to not change the structure of the master equation. Bolu, Turkey.
Energy Technology Data Exchange (ETDEWEB)
Kurt, Arzu; Eryigit, Resul, E-mail: resul@ibu.edu.tr
2015-12-18
The master equation for a charged harmonic oscillator coupled to an electromagnetic reservoir is investigated up to fourth order in the interaction strength by using Krylov averaging method. The interaction is in the velocity-coupling form and includes a diamagnetic term. Exact analytical expressions for the second-, the third-, and the fourth-order contributions to mass renormalization, decay constant, normal and anomalous diffusion coefficients are obtained for the blackbody type environment. It is found that, generally, the third- and the fourth-order contributions have opposite signs when their magnitudes are comparable to that of the second-order one. - Highlights: • Exact analytical expressions for up to the fourth-order master equation are obtained. • High and low temperature limits of anomalous diffusion coefficients are elucidated. • Convergence range of the oscillator and the bath parameters discussed.
Fourth order accurate compact scheme with group velocity control (GVC)
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
For solving complex flow field with multi-scale structure higher order accurate schemes are preferred. Among high order schemes the compact schemes have higher resolving efficiency. When the compact and upwind compact schemes are used to solve aerodynamic problems there are numerical oscillations near the shocks. The reason of oscillation production is because of non-uniform group velocity of wave packets in numerical solutions. For improvement of resolution of the shock a parameter function is introduced in compact scheme to control the group velocity. The newly developed method is simple. It has higher accuracy and less stencil of grid points.
Time-Periodic Solution of a 2D Fourth-Order Nonlinear Parabolic Equation
Indian Academy of Sciences (India)
Xiaopeng Zhao; Changchun Liu
2014-08-01
By using the Galerkin method, we study the existence and uniqueness of time-periodic generalized solutions and time-periodic classical solutions to a fourth-order nonlinear parabolic equation in 2D case.
MULTIPLE POSITIVE SOLUTIONS TO FOURTH-ORDER SINGULAR BOUNDARY VALUE PROBLEMS
Institute of Scientific and Technical Information of China (English)
无
2011-01-01
In this paper,using the Krasnaselskii's fixed point theory in cones and localization method,under more general conditions,the existence of n positive solutions to a class of fourth-order singular boundary value problems is considered.
Block Hybrid Collocation Method with Application to Fourth Order Differential Equations
Directory of Open Access Journals (Sweden)
Lee Ken Yap
2015-01-01
Full Text Available The block hybrid collocation method with three off-step points is proposed for the direct solution of fourth order ordinary differential equations. The interpolation and collocation techniques are applied on basic polynomial to generate the main and additional methods. These methods are implemented in block form to obtain the approximation at seven points simultaneously. Numerical experiments are conducted to illustrate the efficiency of the method. The method is also applied to solve the fourth order problem from ship dynamics.
Fourth-Order Vibrational Transition State Theory and Chemical Kinetics
Stanton, John F.; Matthews, Devin A.; Gong, Justin Z.
2015-06-01
Second-order vibrational perturbation theory (VPT2) is an enormously successful and well-established theory for treating anharmonic effects on the vibrational levels of semi-rigid molecules. Partially as a consequence of the fact that the theory is exact for the Morse potential (which provides an appropriate qualitative model for stretching anharmonicity), VPT2 calculations for such systems with appropriate ab initio potential functions tend to give fundamental and overtone levels that fall within a handful of wavenumbers of experimentally measured positions. As a consequence, the next non-vanishing level of perturbation theory -- VPT4 -- offers only slight improvements over VPT2 and is not practical for most calculations since it requires information about force constants up through sextic. However, VPT4 (as well as VPT2) can be used for other applications such as the next vibrational correction to rotational constants (the ``gammas'') and other spectroscopic parameters. In addition, the marriage of VPT with the semi-classical transition state theory of Miller (SCTST) has recently proven to be a powerful and accurate treatment for chemical kinetics. In this talk, VPT4-based SCTST tunneling probabilities and cumulative reaction probabilities are give for the first time for selected low-dimensional model systems. The prospects for VPT4, both practical and intrinsic, will also be discussed.
Lv, Wei; Tang, Chen; Wang, Wenping
2007-01-01
Noise reduction is one of the largest problems and biggest difficulties involved in electronic speckle pattern interferometry (ESPI). Although the second-order PDEs denoising method is a useful tool of noise reduction for the ESPI fringe patterns, its main drawback is that the second-order PDE model does not remove impulse noise, a 3×3 mean window filter is generally needed to improve the fringes. For overcome this main drawback, in this paper we apply the fourth-order PDE denoising model to the computer-simulated and experimentally obtained ESPI fringe, respectively. In both tests, the fourth-order PDE denoising model clearly outperforms the second-order PDE denoising model. Experimental results have confirmed that the fourth-order PDE denoising model is capable of removing noise in ESPI fringe images effectively.
Linearization of fourth-order ordinary differential equations by point transformations
Energy Technology Data Exchange (ETDEWEB)
Ibragimov, Nail H [Mathematics and Science, Research Centre ALGA: Advances in Lie Group Analysis, Blekinge Institute of Technology, SE-371 79 Karlskrona (Sweden); Meleshko, Sergey V; Suksern, Supaporn [School of Mathematics, Suranaree University of Technology, Nakhon Ratchasima, 30000 (Thailand)], E-mail: supaporn@math.sut.ac.th
2008-06-13
The solution of the problem on linearization of fourth-order equations by means of point transformations is presented here. We show that all fourth-order equations that are linearizable by point transformations are contained in the class of equations which is linear in the third-order derivative. We provide the linearization test and describe the procedure for obtaining the linearizing transformations as well as the linearized equation. For ordinary differential equations of order greater than 4 we obtain necessary conditions, which separate all linearizable equations into two classes.
On the third- and fourth-order constants of incompressible isotropic elasticity.
Destrade, Michel; Ogden, Raymond W
2010-12-01
Consider the constitutive law for an isotropic elastic solid with the strain-energy function expanded up to the fourth order in the strain and the stress up to the third order in the strain. The stress-strain relation can then be inverted to give the strain in terms of the stress with a view to considering the incompressible limit. For this purpose, use of the logarithmic strain tensor is of particular value. It enables the limiting values of all nine fourth-order elastic constants in the incompressible limit to be evaluated precisely and rigorously. In particular, it is explained why the three constants of fourth-order incompressible elasticity μ, Ā, and D are of the same order of magnitude. Several examples of application of the results follow, including determination of the acoustoelastic coefficients in incompressible solids and the limiting values of the coefficients of nonlinearity for elastic wave propagation.
Fourth-order partial differential equation noise removal on welding images
Halim, Suhaila Abd; Ibrahim, Arsmah; Sulong, Tuan Nurul Norazura Tuan; Manurung, Yupiter HP
2015-10-01
Partial differential equation (PDE) has become one of the important topics in mathematics and is widely used in various fields. It can be used for image denoising in the image analysis field. In this paper, a fourth-order PDE is discussed and implemented as a denoising method on digital images. The fourth-order PDE is solved computationally using finite difference approach and then implemented on a set of digital radiographic images with welding defects. The performance of the discretized model is evaluated using Peak Signal to Noise Ratio (PSNR). Simulation is carried out on the discretized model on different level of Gaussian noise in order to get the maximum PSNR value. The convergence criteria chosen to determine the number of iterations required is measured based on the highest PSNR value. Results obtained show that the fourth-order PDE model produced promising results as an image denoising tool compared with median filter.
Fourth-order partial differential equation noise removal on welding images
Energy Technology Data Exchange (ETDEWEB)
Halim, Suhaila Abd; Ibrahim, Arsmah; Sulong, Tuan Nurul Norazura Tuan [Center of Mathematics Studies, Faculty of Computer and Mathematical Sciences, Universiti Teknologi MARA, 40450 Shah Alam, Selangor. Malaysia (Malaysia); Manurung, Yupiter HP [Advanced Manufacturing Technology Center, Faculty of Mechanical Engineering, Universiti TEknologi MARA, 40450 Shah Alam, Selangor. Malaysia (Malaysia)
2015-10-22
Partial differential equation (PDE) has become one of the important topics in mathematics and is widely used in various fields. It can be used for image denoising in the image analysis field. In this paper, a fourth-order PDE is discussed and implemented as a denoising method on digital images. The fourth-order PDE is solved computationally using finite difference approach and then implemented on a set of digital radiographic images with welding defects. The performance of the discretized model is evaluated using Peak Signal to Noise Ratio (PSNR). Simulation is carried out on the discretized model on different level of Gaussian noise in order to get the maximum PSNR value. The convergence criteria chosen to determine the number of iterations required is measured based on the highest PSNR value. Results obtained show that the fourth-order PDE model produced promising results as an image denoising tool compared with median filter.
Fourth-Order Interference on Polarization Beats with Phase-Conjugation Geometry
Institute of Scientific and Technical Information of China (English)
ZHANG Yan-Peng; SUN Li-Qun; TANG Tian-Tong; ZHANG Lu; FU Pan-Ming
2000-01-01
The effect of fourth-order coherence on ultrafast modulation spectroscopy (UMS) with phase-conjugation geome try (PCUMS) in a cascade three-level system is investigated using chaotic and phase-diffusion models. It has been found that the modulation terms of the beat signal depend on the second-order coherence function, and different stochastic models of the laser field affect only the fourth-order coherence function. The difference between the PCUMS and UMS is discussed from a physical viewpoint.
The Complex Ambiguity Function Based on Downsampled Fourth-Order Statistics
Institute of Scientific and Technical Information of China (English)
MAYongfeng; ZHANGWeiqiang; TAORan
2004-01-01
Aiming at the problem of target detection in passive radar in correlated noise surroundings, we present a new estimation of the Complex ambiguity function based on Downsampled fourth-order statistics (CAF-DFOS) to improve the performances of the traditional Complex ambiguity function based on Second-order statistics (CAF-SOS) and the existing Complex ambiguity function based on Fourth-order statistics (CAF-FOS). Both the theory and the simulations show that in the aspect of Gaussian noise suppression, its performance is better than the CAF-SOS algorithm; in the aspect of estimate variance and frequency resolution, its performance is better than the CAF-FOS algorithm.
Application of Fourth Order Vibrational Perturbation Theory with Analytic Hartree-Fock Force Fields
Gong, Justin Z.; Matthews, Devin A.; Stanton, John F.
2014-06-01
Fourth-Order Rayleigh-Schrodinger Perturbation Theory (VPT4) is applied to a series of small molecules. The quality of results have been shown to be heavily dependent on the quality of the quintic and sextic force constants used and that numerical sextic force constants converge poorly and are unreliable for VPT4. Using analytic Hartree-Fock force constants, it is shown that these analytic higher-order force constants are comparable to corresponding force constants from numerical calculations at a higher level of theory. Calculations show that analytic Hartree-Fock sextic force constants are reliable and can provide good results with Fourth-Order Rayleigh-Schrodinger Perturbation Theory.
Directory of Open Access Journals (Sweden)
Babatunde S. Ogundare
2006-01-01
Full Text Available This article concerns the fourth order differential equation $$ x^{(iv}+ax'''+bx''+g(x'+h(x=p(t. $$ Using the Cauchy formula for the particular solution of non-homogeneous linear differential equations with constant coefficients, we prove that the solution and its derivatives up to order three are bounded.
Entropy Diagnostics for Fourth Order Partial Differential Equations in Conservation Form
Directory of Open Access Journals (Sweden)
Phil Broadbridge
2008-09-01
Full Text Available The entropy evolution behaviour of a partial differential equation (PDE in conservation form, may be readily discerned from the sign of the local source term of Shannon information density. This can be easily used as a diagnostic tool to predict smoothing and non-smoothing properties, as well as positivity of solutions with conserved mass. The familiar fourth order diffusion equations arising in applications do not have increasing Shannon entropy. However, we obtain a new class of nonlinear fourth order diffusion equations that do indeed have this property. These equations also exhibit smoothing properties and they maintain positivity. The counter-intuitive behaviour of fourth order diffusion, observed to occur or not occur on an apparently ad hoc basis, can be predicted from an easily calculated entropy production rate. This is uniquely defined only after a technical definition of the irreducible source term of a reaction diffusion equation.
Image restoration with surface-based fourth-order partial differential equation
Lu, Bibo; Liu, Qiang
2010-07-01
This paper presents an edge-preserving fourth order partial differential equation (PDE) for image restoration derived from a new surface-based energy functional. The corresponding fourth order PDE can preserve edges and avoid the staircase effect. The proposed model contains a function of gradient norm as an edge detector, which controls the diffusion speed according to the local structure of the image and preserves more details. Denoising results are given and we have also compared our method with some related PDE models.
Institute of Scientific and Technical Information of China (English)
SHA Wei; HUANG Zhi-Xiang; WU Xian-Liang; CHEN Ming-Sheng
2006-01-01
Using symplectic integrator propagator, a three-dimensional fourth-order symplectic finite difference time domain (SFDTD) method is studied, which is of the fourth order in both the time and space domains. The method is nondissipative and can save more memory compared with the traditional FDTD method. The total field and scattered field (TF-SF) technique is derived for the SFDTD method to provide the incident wave source conditions. The bistatic radar cross section (RCS) of a dielectric sphere is computed by using the SFDTD method for the first time. Numerical results suggest that the SFDTD algorithm acquires better stability and accuracy compared with the traditional FDTD method.
On the joint distribution of surface slopes for the fourth order nonlinear random sea waves
Institute of Scientific and Technical Information of China (English)
张书文; 孙孚; 管长龙
1999-01-01
Based upon the nonlinear model of Longuet-Higgins the joint distribution of wave surface slopes is theoretically investigated. It is shown that in the fourth order approximation, the distribution is given by truncated Gram-Charlier series. The types of wave-wave coupling interactions are related to the order of approximation to nonlinearity of sea surface, which eventually defines the truncated term of the Gram-Charlier series. For each order approximation, the coefficients in the series are modified comparatively to the corresponding ones for the previous order approximation. If the nonlinear effect of the kurtosis is considered, the wave surface must be as accurate at least as to the third order approximation, and with regard to skewness, the wave surface must be as accurate at least as to the fourth order approximation.
A STABILITY RESULT ON SOLUTIONS TO CERTAIN FOURTH ORDER NON-HOMOGENEOUS DIFFERENTIAL EQUATIONS
Institute of Scientific and Technical Information of China (English)
A.M.A.; Abou-El-Ela; A.I.; Sadek; E.S.; Farghaly
2009-01-01
In this paper,we study the fourth order non-homogeneous differential equations x(4) + f1()+ f2() + f3(■) + f4(x) = p(t,x,■,,x),and obtain suffcient conditions,under which the solutions to the system tend to zero as t →∞.
A STABILITY RESULT ON SOLUTIONS TO CERTAIN FOURTH ORDER NON-HOMOGENEOUS DIFFERENTIAL EQUATIONS
Institute of Scientific and Technical Information of China (English)
A.M.A.Abou-El-Ela; A.I.Sadek; E.S.Farghaly
2009-01-01
In this paper,we study the fourth order non-homogeneous differential equations x(4)+f1(x)x+f2(x)+f3(x)+f4 (x)= p(t,x,x,x,x),and obtain sufficient conditions,under which the solutions to the system tend to zero as t→∞.
Fourth-Order Interference in Femtosecond Spontaneous Parametric Down-Conversion
Institute of Scientific and Technical Information of China (English)
JIANG Yun-Kun; SHI Bao-Sen; LI Jian; FAN Xiao-Feng; GUO Guang-Can
2000-01-01
We report a fourth-order interference experiment in which pairs of photons are produced in spontaneous parametric down-conversion pumped by femtosecond pulses interfere in a Hong-Ou-Mandel interferometer. The visibilityof the interference is (64±4)%, exceeding the bound of 50% predicted by classical interference theory.
Polarization modulational instability in a birefringent optical ﬁber with fourth order dispersion
Indian Academy of Sciences (India)
R Ganapathy; V C Kuriakose
2001-10-01
We obtain conditions for the occurrence of polarization modulational instability in the anomalous and normal dispersion regimes for the coupled nonlinear Schrödinger equation modelling fourth order dispersion effects when the linearly polarized pump is oriented at arbitrary angles with respect to the slow and fast axes of the birefringent ﬁber.
High-resolution harmonic retrieval using the full fourth-order cumulant
Vossen, S.H.J.A.; Naus, H.W.L.; Zwamborn, A.P.M.
2010-01-01
The harmonic retrieval (HR) problem concerns the estimation of the frequencies in a sum of real or complex harmonics. Both correlation and cumulant-based approaches are used for this purpose. Cumulant-based HR algorithms use a single 1-D slice of the fourth-order cumulant that is estimated directly
Institute of Scientific and Technical Information of China (English)
SHI Dongyang; CHEN Shaochun; Ichiro Hagiwara
2005-01-01
The purpose of this paper is to obtain the optimal error estimates of O(h) for the highly nonconforming elements to a fourth order variational inequality with curvature obstacle in a convex domain with simply supported boundary by using the novel function splitting method and the orthogonal properties of the nonconforming finite element spaces.Morley's element approximation is our special case.
NON C0 NONCONFORMING ELEMENTS FOR ELLIPTIC FOURTH ORDER SINGULAR PERTURBATION PROBLEM
Institute of Scientific and Technical Information of China (English)
Shao-chun Chen; Yong-cheng Zhao; Dong-yang Shi
2005-01-01
In this paper we give a convergence theorem for non C0 nonconforming finite element to solve the elliptic fourth order singular perturbation problem. Two such kind of elements, a nine parameter triangular element and a twelve parameter rectangular element both with double set parameters, are presented. The convergence and numerical results of the two elements are given.
Positive Solutions of a Nonlinear Fourth-order Integral Boundary Value Problem
Directory of Open Access Journals (Sweden)
Benaicha Slimane
2016-07-01
Full Text Available In this paper, the existence of positive solutions for a nonlinear fourth-order two-point boundary value problem with integral condition is investigated. By using Krasnoselskii’s fixed point theorem on cones, sufficient conditions for the existence of at least one positive solutions are obtained.
Conservative fourth-order time integration of non-linear dynamic systems
DEFF Research Database (Denmark)
Krenk, Steen
2015-01-01
An energy conserving time integration algorithm with fourth-order accuracy is developed for dynamic systems with nonlinear stiffness. The discrete formulation is derived by integrating the differential state-space equations of motion over the integration time increment, and then evaluating the re...... integration of oscillatory systems with only a few integration points per period. Three numerical examples demonstrate the high accuracy of the algorithm. (C) 2015 Elsevier B.V. All rights reserved.......An energy conserving time integration algorithm with fourth-order accuracy is developed for dynamic systems with nonlinear stiffness. The discrete formulation is derived by integrating the differential state-space equations of motion over the integration time increment, and then evaluating...... is a direct fourth-order accurate representation of the original differential equations. This fourth-order form is energy conserving for systems with force potential in the form of a quartic polynomial in the displacement components. Energy conservation for a force potential of general form is obtained...
Strategic Competence as a Fourth-Order Factor Model: A Structural Equation Modeling Approach
Phakiti, Aek
2008-01-01
This article reports on an empirical study that tests a fourth-order factor model of strategic competence through the use of structural equation modeling (SEM). The study examines the hierarchical relationship of strategic competence to (a) strategic knowledge of cognitive and metacognitive strategy use in general (i.e., trait) and (b) strategic…
Energy Technology Data Exchange (ETDEWEB)
Fiedler, B.; Schimming, R.
1983-01-01
The fourth order field equations proposed by TREDER with a linear combination of BACH's tensor and EINSTEIN's tensor on the left-hand side admit static centrally symmetric solutions which are analytical and non-flat in some neighborhood of the centre of symmetry.
Exact Controllability for the Fourth Order Schr(o)dinger Equation
Institute of Scientific and Technical Information of China (English)
Chuang ZHENG; Zhongcheng ZHOU
2012-01-01
The boundary controllability of the fourth order Schr(o)dinger equation in a bounded domain is studied.By means of an L2-Neumann boundary control,the authors prove that the solution is exactly controllable in H-2(Ω) for an arbitrarily small time.The method of proof combines both the HUM (Hilbert Uniqueness Method) and multiplier techniques.
Periodic and subharmonic solutions for fourth-order p-Laplacian difference equations
Directory of Open Access Journals (Sweden)
Xia Liu
2014-01-01
Full Text Available Using critical point theory, we obtain criteria for the existence and multiplicity of periodic and subharmonic solutions to fourth-order p-Laplacian difference equations. The proof is based on the Linking Theorem in combination with variational technique. Recent results in the literature are generalized and improved.
Multiple Solutions for a Fourth-order Asymptotically Linear Elliptic Problem
Institute of Scientific and Technical Information of China (English)
Ai Xia QIAN; Shu Jie LI
2006-01-01
Under simple conditions, we prove the existence of three solutions for a fourth-order asymptotically linear elliptic boundary value problem. For the resonance case at infinity, we do not need to assume any more conditions to ensure the boundedness of the (PS) sequence of the corresponding functional.
NONTRIVIAL SOLUTIONS TO SINGULAR BOUNDARY VALUE PROBLEMS FOR FOURTH-ORDER DIFFERENTIAL EQUATIONS
Institute of Scientific and Technical Information of China (English)
无
2008-01-01
The singular boundary value problems for fourth-order differential equations are considered under some conditions concerning the first eigenvalues of the relevant linear operators. Sufficient conditions which guarantee the existence of nontrivial solutions are obtained. We use the topological degree to prove our main results.
Stokes' first problem for the fourth order fluid in a porous half space
Institute of Scientific and Technical Information of China (English)
T.Hayat; F.Shahazad; M.Ayub
2007-01-01
In this study, the flow of a fourth order fluid in a porous half space is modeled. By using the modified Darcy's law, the flow over a suddenly moving flat plate is studied numerically. The influence of various param-eters of interest on the velocity profile is revealed.
STABILITY OF SOLUTIONS TO CERTAIN FOURTH-ORDER DELAY DIFFERENTIAL EQUATIONS
Institute of Scientific and Technical Information of China (English)
无
2010-01-01
By the Lyapunov functional approach, some better results on the asymptotic stabiBy the Lyapunov functional approach, some better results on the asymptotic stability and global asymptotic stability of zero solution to a certain fourth-order non-linear differential equation with delay are obtained.
Directory of Open Access Journals (Sweden)
Massimiliano Ferrara
2016-01-01
Full Text Available This paper discusses the existence of infinitely many periodic solutions for a semilinear fourth-order impulsive differential inclusion with a perturbed nonlinearity and two parameters. The approach is based on a critical point theorem for nonsmooth functionals.
Symplectic fourth-order maps for the collisional N-body problem
Dehnen, Walter
2016-01-01
We study analytically and experimentally certain symplectic and time-reversible N-body integrators which employ a Kepler solver for each pair-wise interaction, including the method of Hernandez & Bertschinger (2015). Owing to the Kepler solver, these methods treat close two-body interactions correctly, while close three-body encounters contribute to the truncation error at second order and above. The second-order errors can be corrected to obtain a fourth-order scheme with little computational overhead. We generalise this map to an integrator which employs a Kepler solver only for selected interactions and yet retains fourth-order accuracy without backward steps. In this case, however, two-body encounters not treated via a Kepler solver contribute to the truncation error.
Symplectic fourth-order maps for the collisional N -body problem
Dehnen, Walter; Hernandez, David M.
2017-02-01
We study analytically and experimentally certain symplectic and time-reversible N-body integrators which employ a Kepler solver for each pair-wise interaction, including the method of Hernandez & Bertschinger (2015). Owing to the Kepler solver, these methods treat close two-body interactions correctly, while close three-body encounters contribute to the truncation error at second order and above. The second-order errors can be corrected to obtain a fourth-order scheme with little computational overhead. We generalise this map to an integrator which employs a Kepler solver only for selected interactions and yet retains fourth-order accuracy without backward steps. In this case, however, two-body encounters not treated via a Kepler solver contribute to the truncation error.
Directory of Open Access Journals (Sweden)
Yi Xu
2013-01-01
Full Text Available We propose a fourth-order total bounded variation regularization model which could reduce undesirable effects effectively. Based on this model, we introduce an improved split Bregman iteration algorithm to obtain the optimum solution. The convergence property of our algorithm is provided. Numerical experiments show the more excellent visual quality of the proposed model compared with the second-order total bounded variation model which is proposed by Liu and Huang (2010.
Fourth-Order Deferred Correction Scheme for Solving Heat Conduction Problem
Directory of Open Access Journals (Sweden)
D. Yambangwai
2013-01-01
Full Text Available A deferred correction method is utilized to increase the order of spatial accuracy of the Crank-Nicolson scheme for the numerical solution of the one-dimensional heat equation. The fourth-order methods proposed are the easier development and can be solved by using Thomas algorithms. The stability analysis and numerical experiments have been limited to one-dimensional heat-conducting problems with Dirichlet boundary conditions and initial data.
Comment on "Perturbative method to solve fourth-order gravity field equations"
Campanelli, M
1995-01-01
We reconsider the cosmic string perturbative solution to the classical fourth-order gravity field equations, obtained in Ref.\\cite{CLA94}, and we obtain that static, cylindricaly symmetric gauge cosmic strings, with constant energy density, can contain only \\beta-terms in the first order corrections to the interior gravitational field, while the exact exterior solution is a conical spacetime with deficit angle D=8\\pi\\mu.
Initial value problem for a class of fourth-order nonlinear wave equations
Institute of Scientific and Technical Information of China (English)
Guo-wang CHEN; Chang-shun HOU
2009-01-01
In this paper, existence and uniqueness of the generalized global solution and the classical global solution to the initial value problem for a class of fourth-order nonlinear wave equations are studied in the fractional order Sobolev space using the contraction mapping principle and the extension theorem. The sufficient conditions for the blow up of the solution to the initial value problem are given.
A Table of Third and Fourth Order Feynman Diagrams of the Interacting Fermion Green's Function
Mathar, R J
2005-01-01
The Feynman diagrams of the Green's function expansion of fermions interacting with a non-relativistic 2-body interaction are displayed in first, second and third order of the interaction as 2, 10 and 74 diagrams, respectively. A name convention for the diagrams is proposed and then used to tabulate the 706 diagrams of fourth order. The Hartree-Fock approximation summons up 2, 8, 40 and 224 of them, respectively.
A FOURTH ORDER DERIVATIVE-FREE OPERATOR MARCHING METHOD FOR HELMHOLTZ EQUATION IN WAVEGUIDES
Institute of Scientific and Technical Information of China (English)
Ya Yan Lu
2007-01-01
A fourth-order operator marching method for the Helmholtz equation in a waveguide is developed in this paper. It is derived from a new fourth-order exponential integrator for linear evolution equations. The method improves the second-order accuracy associated with the widely used step-wise coupled mode method where the waveguide is approximated by segments that are uniform in the propagation direction. The Helmholtz equation is solved using a one-way reformulation based on the Dirichlet-to-Neumann map. An alternative version closely related to the coupled mode method is also given. Numerical results clearly indicate that the method is more accurate than the coupled mode method while the required computing effort is nearly the same.
Fourth order wave equation in Bhabha-Madhavarao spin-$\\frac{3}{2}$ theory
Markov, Yu A; Bondarenko, A I
2016-01-01
Within the framework of the Bhabha-Madhavarao formalism, a consistent approach to the derivation of a system of the fourth order wave equations for the description of a spin-$\\frac{3}{2}$ particle is suggested. For this purpose an additional algebraic object, the so-called $q$-commutator ($q$ is a primitive fourth root of unity) and a new set of matrices $\\eta_{\\mu}$, instead of the original matrices $\\beta_{\\mu}$ of the Bhabha-Madhavarao algebra, are introduced. It is shown that in terms of the $\\eta_{\\mu}$ matrices we have succeeded in reducing a procedure of the construction of fourth root of the fourth order wave operator to a few simple algebraic transformations and to some operation of the passage to the limit $z \\rightarrow q$, where $z$ is some (complex) deformation parameter entering into the definition of the $\\eta$-matrices. In addition, a set of the matrices ${\\cal P}_{1/2}$ and ${\\cal P}_{3/2}^{(\\pm)}(q)$ possessing the properties of projectors is introduced. These operators project the matrices ...
Spectrum of a class of fourth order left-definite differential operators
Institute of Scientific and Technical Information of China (English)
GAO Yun-lan; SUN Jiong
2008-01-01
The spectrum of a class of fourth order left-definite differential operators is studied. By using the theory of indefinite differential operators in Krein space and the relationship between left-definite and right-definite operators,the following conclusions are obtained: if a fourth order differential operator with a self-adjoint boundary condition that is left-definite and right-indefinite,then all its eigenvalues are real,and there exist countably infinitely many positive and negative eigenvalues which are unbounded from below and above,have no finite cluster point and can be indexed to satisfy the inequality …≤λ-2≤λ-1≤λ-0＜0＜λ0≤λ1≤λ2≤…
Third- and fourth-order constants of incompressible soft solids and the acousto-elastic effect.
Destrade, Michel; Gilchrist, Michael D; Saccomandi, Giuseppe
2010-05-01
Acousto-elasticity is concerned with the propagation of small-amplitude waves in deformed solids. Results previously established for the incremental elastodynamics of exact non-linear elasticity are useful for the determination of third- and fourth-order elastic constants, especially in the case of incompressible isotropic soft solids, where the expressions are particularly simple. Specifically, it is simply a matter of expanding the expression for ρv(2), where ρ is the mass density and v the wave speed, in terms of the elongation e of a block subject to a uniaxial tension. The analysis shows that in the resulting expression: ρv(2) = a+be+ce(2), say, a depends linearly on μ; b on μ and A; and c on μ, A, and D, the respective second-, third, and fourth-order constants of incompressible elasticity, for bulk shear waves and for surface waves.
Fujita-Liouville Type Theorem for Coupled Fourth-Order Parabolic Inequalities
Institute of Scientific and Technical Information of China (English)
Zhaoxin JIANG; Sining ZHENG
2012-01-01
This paper deals with a coupled system of fourth-order parabolic inequalities ｜u｜ ≥ -△2u + ｜v｜q,｜v｜t ≥ -△2v + ｜u｜P in S =Rn × R+ with p,q ＞ 1,n ≥ 1.A FujitaLiouville type theorem is established that the inequality system does not admit nontrivial nonnegative global solutions on S whenever n/4 ≤ max(p+1/pq-1,q+L/pq-1).Since the general maximum-comparison principle does not hold for the fourth-order problem,the authors use the test function method to get the global non-existence of nontrivial solutions.
COMPACT FOURTH-ORDER FINITE DIFFERENCE SCHEMES FOR HELMHOLTZ EQUATION WITH HIGH WAVE NUMBERS
Institute of Scientific and Technical Information of China (English)
Yiping Fu
2008-01-01
In this paper,two fourth-order accurate compact difference schemes are presented for solving the Helmholtz equation in two space dimensions when the corresponding wave numbers are large.The main idea is to derive and to study a fourth-order accurate compact difference scheme whose leading truncation term,namely,the O(h4) term,is independent of the wave number and the sohrtion of the Helmholtz equation.The convergence property of the compact schemes are analyzed and the implementation of solving the resulting linear algebraic system based on a FFT approach is considered.Numerical results are presented,which support our theoretical predictions.Mathematics subject classification:65M06,65N12.
Symmetry Reduction and Cauchy Problems for a Class of Fourth-Order Evolution Equations
Institute of Scientific and Technical Information of China (English)
LI Ji-Na; ZHANG Shun-Li
2008-01-01
We exploit higher-order conditional symmetry to reduce initial-value problems for evolution equations to Cauehy problems for systems of ordinary differential equations (ODEs).We classify a class of fourth-order evolution equations which admit certain higher-order generalized conditional symmetries (GCSs) and give some examples to show the main reduction procedure.These reductions cannot be derived within the framework of the standard Lie approach,which hints that the technique presented here is something essential for the dimensional reduction of evolution equations.
2014-01-01
A generalization of the usual gauge symmetry leads to fourth-order gauge field equations, which imply a new constant force independent of distances. The force associated with the new $U_1$ gauge symmetry is repulsive among baryons. Such a constant force based on baryon charge conservation gives a field-theoretic understanding of the accelerated cosmic-expansion in the observable portion of the universe dominated by baryon galaxies. In consistent with all conservation laws and known forces, a ...
Joint frequency, 2D AOA and polarization estimation using fourth-order cumulants
Institute of Scientific and Technical Information of China (English)
王建英; 陈天琪
2000-01-01
Based on fourth-order cumulant and ESPRIT algorithm, a novel joint frequency, two-dimensional angle of arrival (2D AOA) and the polarization estimation method of incoming multiple independent spatial narrow-band non-Gaussian signals in arbitrary Gaussian noise environment are proposed . The array is composed of crossed dipoles parallel to the coordinate axes. The crossed dipole positions are arbitrarily distributed. Computer simulation confirms its feasibility.
Joint frequency, 2D AOA and polarization estimation using fourth-order cumulants
Institute of Scientific and Technical Information of China (English)
无
2000-01-01
Based on fourth-order cumulant and ESPRIT algorithm, a novel joint frequency, two-dimensional angle of arrival (2D AOA) and the polarization estimation method of incoming multiple independent spatial narrow-band non-Gaussian signals in arbitrary Gaussian noise environment are proposed. The array is composed of crossed dipoles parallel to the coordinate axes. The crossed dipole positions are arbitrarily distributed. Computer simulation confirms its feasibility.
Infinitely many solutions for a fourth-order boundary-value problem
Directory of Open Access Journals (Sweden)
Seyyed Mohsen Khalkhali
2012-09-01
Full Text Available In this article we consider the existence of infinitely many solutions to the fourth-order boundary-value problem $$displaylines{ u^{iv}+alpha u''+eta(x u=lambda f(x,u+h(u,quad xin]0,1[cr u(0=u(1=0,cr u''(0=u''(1=0,. }$$ Our approach is based on variational methods and critical point theory.
Fourth-Order Four-Point Boundary Value Problem: A Solutions Funnel Approach
Directory of Open Access Journals (Sweden)
Panos K. Palamides
2012-01-01
Full Text Available We investigate the existence of positive or a negative solution of several classes of four-point boundary-value problems for fourth-order ordinary differential equations. Although these problems do not always admit a (positive Green's function, the obtained solution is still of definite sign. Furthermore, we prove the existence of an entire continuum of solutions. Our technique relies on the continuum property (connectedness and compactness of the solutions funnel (Kneser's Theorem, combined with the corresponding vector field.
Image Denoising based on Fourth-Order Partial Differential Equations: A Survey
Directory of Open Access Journals (Sweden)
Anand Swaroop Khare,
2013-04-01
Full Text Available Reduction of noise is essential especially in the fieldof image processing. Several researchers arecontinuously working in this direction and providesome good insights, but still there are lot of scope inthis field.Noise mixed with image is harmful forimage processing. Inthis paper we survey severalaspects of image denoising and fourth-order partialdifferential equation.We also discuss severaltraditional methodology used with their advantagesand disadvantages. We also provide a deep analysisbased on the literature work from the previousresearch.
Nuclear axial current operators to fourth order in chiral effective field theory
Krebs, H; Epelbaum, E.; Meißner, U.-G
2016-01-01
We present the complete derivation of the nuclear axial charge and current operators as well as the pseudoscalar operators to fourth order in the chiral expansion relative to the dominant one-body contribution using the method of unitary transformation. We demonstrate that the unitary ambiguity in the resulting operators can be eliminated by the requirement of renormalizability and by matching of the pion-pole contributions to the nuclear forces. We give expressions for the renormalized singl...
Fourth-order dispersion mediated solitonic radiations in HC-PCF cladding.
Benabid, F; Biancalana, F; Light, P S; Couny, F; Luiten, A; Roberts, P J; Peng, Jiahui; Sokolov, Alexei V
2008-11-15
We observe experimentally, for the first time to our knowledge, the simultaneous emission of two strong conjugate resonant dispersive waves by optical solitons. The effect is observed in a small waveguiding glass feature within the cladding of a Kagome hollow-core photonic crystal fiber. We demonstrate theoretically that the phenomenon is attributed to the unusually high fourth-order dispersion coefficient of the waveguiding feature.
Efficient fourth order symplectic integrators for near-harmonic separable Hamiltonian systems
Nielsen, Kristian Mads Egeris
2015-01-01
Efficient fourth order symplectic integrators are proposed for numerical integration of separable Hamiltonian systems H(p,q)=T(p)+V(q). Symmetric splitting coefficients with five to nine stages are obtained by higher order decomposition of the simple harmonic oscillator. The performance of the methods is evaluated for various Hamiltonian systems: Integration errors are compared to those of acclaimed integrators composed by S. Blanes et al. (2013), W. Kahan et al. (1999) and H. Yoshida (1990). Numerical tests indicate that the integrators obtained in this paper perform significantly better than previous integrators for common Hamiltonian systems.
Calatroni, Luca
2013-08-01
We present directional operator splitting schemes for the numerical solution of a fourth-order, nonlinear partial differential evolution equation which arises in image processing. This equation constitutes the H -1-gradient flow of the total variation and represents a prototype of higher-order equations of similar type which are popular in imaging for denoising, deblurring and inpainting problems. The efficient numerical solution of this equation is very challenging due to the stiffness of most numerical schemes. We show that the combination of directional splitting schemes with implicit time-stepping provides a stable and computationally cheap numerical realisation of the equation.
Pion-nucleon scattering in chiral perturbation theory II: Fourth order calculation
Fettes, N
2000-01-01
We analyze elastic pion-nucleon scattering to fourth order in heavy-baryon chiral perturbation theory, extending the third-order study published in Nucl. Phys. A 640 (1998) 199. We use various partial-wave analyses to pin down the low-energy constants from data in the physical region. The S-wave scattering lengths are consistent with recent determinations from pionic hydrogen and deuterium. We find an improved description of the P-waves. We also discuss the pion-nucleon sigma term and problems related to the prediction of the subthreshold parameters.
Pion-nucleon scattering in chiral perturbation theory; 2, Fourth order calculation
Fettes, N; Fettes, Nadia; Meissner, Ulf-G.
2000-01-01
We analyse elastic-pion nucleon scattering to fourth order in heavy baryonchiral perturbation theory, extending the third order study published in Nucl.Phys. A640 (1998) 199. We use various partial wave analyses to pin down thelow-energy constants from data in the physical region. The S-wave scatteringlengths are consistent with recent determinations from pionic hydrogen anddeuterium. We find an improved description of the P-waves. We also discuss thepion-nucleon sigma term and problems related to the prediction of thesubthreshold parameters.
Lagrangian perturbations and the matter bispectrum I: fourth-order model for non-linear clustering
Energy Technology Data Exchange (ETDEWEB)
Rampf, Cornelius [Institut für Theoretische Teilchenphysik und Kosmologie, RWTH Aachen, Physikzentrum RWTH-Melaten, D-52056 Aachen (Germany); Buchert, Thomas, E-mail: rampf@physik.rwth-aachen.de, E-mail: buchert@obs.univ-lyon1.fr [Université de Lyon, Observatoire de Lyon, Centre de Recherche Astrophysique de Lyon, CNRS UMR 5574: Université Lyon 1 and École Normale Supérieure de Lyon, 9 avenue Charles André, F-69230 Saint-Genis-Laval (France)
2012-06-01
We investigate the Lagrangian perturbation theory of a homogeneous and isotropic universe in the non-relativistic limit, and derive the solutions up to the fourth order. These solutions are needed for example for the next-to-leading order correction of the (resummed) Lagrangian matter bispectrum, which we study in an accompanying paper. We focus on flat cosmologies with a vanishing cosmological constant, and provide an in-depth description of two complementary approaches used in the current literature. Both approaches are solved with two different sets of initial conditions — both appropriate for modelling the large-scale structure. Afterwards we consider only the fastest growing mode solution, which is not affected by either of these choices of initial conditions. Under the reasonable approximation that the linear density contrast is evaluated at the initial Lagrangian position of the fluid particle, we obtain the nth-order displacement field in the so-called initial position limit: the nth order displacement field consists of 3(n-1) integrals over n linear density contrasts, and obeys self-similarity. Then, we find exact relations between the series in Lagrangian and Eulerian perturbation theory, leading to identical predictions for the density contrast and the peculiar-velocity divergence up to the fourth order.
Fourth-order strain-gradient phase mixture model for nanocrystalline fcc materials
Klusemann, Benjamin; Bargmann, Swantje; Estrin, Yuri
2016-12-01
The proposed modeling approach for nanocrystalline materials is an extension of the local phase mixture model introduced by Kim et al (2000 Acta Mater. 48 493-504). Local models cannot account for any non-uniformities or strain patterns, i.e. such models describe the behavior correctly only as long as it is homogeneous. In order to capture heterogeneities, the phase mixture model is augmented with gradient terms of higher order, namely second and fourth order. Different deformation mechanisms are assumed to operate in grain interior and grain boundaries concurrently. The deformation mechanism in grain boundaries is associated with diffusional mass transport along the boundaries, while in the grain interior dislocation glide as well as diffusion controlled mechanisms are considered. In particular, the mechanical response of nanostructured polycrystals is investigated. The model is capable of correctly predicting the transition of flow stress from Hall-Petch behavior in conventional grain size range to an inverse Hall-Petch relation in the nanocrystalline grain size range. The consideration of second- and fourth-order strain gradients allows non-uniformities within the strain field to represent strain patterns in combination with a regularization effect. Details of the numerical implementation are provided.
Levi, Michele
2016-01-01
In this work we complete the spin dependent conservative dynamics of inspiralling compact binaries at the fourth post-Newtonian order, and in particular the recent derivation of the next-to-next-to-leading order spin-squared interaction potential. We derive the physical equations of motion of the position and the spin from a direct variation of the action. Further, we derive the quadratic in spin Hamiltonians, as well as their expressions in the center of mass frame. We construct the conserved integrals of motion, which form the Poincare algebra. This construction provided a consistency check for the validity of our result, which is crucial in particular in the current absence of another independent derivation of the next-to-next-to-leading order spin-squared interaction. Finally, we provide here the complete gauge invariant relations among the binding energy, angular momentum, and orbital frequency of an inspiralling binary with generic compact spinning components to the fourth post-Newtonian order. These hi...
Yefet, Amir; Petropoulos, Peter G.
2001-04-01
We consider a model explicit fourth-order staggered finite-difference method for the hyperbolic Maxwell's equations. Appropriate fourth-order accurate extrapolation and one-sided difference operators are derived in order to complete the scheme near metal boundaries and dielectric interfaces. An eigenvalue analysis of the overall scheme provides a necessary, but not sufficient, stability condition and indicates long-time stability. Numerical results verify both the stability analysis, and the scheme's fourth-order convergence rate over complex domains that include dielectric interfaces and perfectly conducting surfaces. For a fixed error level, we find the fourth-order scheme is computationally cheaper in comparison to the Yee scheme by more than an order of magnitude. Some open problems encountered in the application of such high-order schemes are also discussed.
Statistical distribution of surface elevation for the fourth order nonlinear random sea waves
Institute of Scientific and Technical Information of China (English)
管长龙; 孙孚
1997-01-01
Based upon the nonlinear model of random sea waves, the statistical distribution of wave surface elevation exact to the fourth order is derived as the truncated Gram-Charlier series, by calculating directly each order moment. The phenomenon found by Huang et al. that the agreement between observed data and investigated series deteriorates much more when the series is kept to λ8 is explained. The effect of the approximation order on the truncation of series and the determination of coefficients is investigated. For the mth order approximation, the derived series is truncated at H3m-3 with the absence of H3m-4, and the coefficients of H3m-3 and H3m-6 are connected by a simple algebraic relation.
The Dirac equation as one fourth-order equation for one function -- a general form
Akhmeteli, Andrey
2015-01-01
Previously (A. Akhmeteli, J. Math. Phys., v. 52, p. 082303 (2011)), the Dirac equation in an arbitrary electromagnetic field was shown to be generally equivalent to a fourth-order equation for just one component of the four-component Dirac spinor function. This was done for a specific (chiral) representation of gamma-matrices and for a specific component. In the current work, the result is generalized for a general representation of gamma-matrices and a general component (satisfying some conditions). The resulting equivalent of the Dirac equation is also much more symmetric than that of the previous work and should be useful in applications of the Dirac equation.
A New Method of Embedded Fourth Order with Four Stages to Study Raster CNN Simulation
Institute of Scientific and Technical Information of China (English)
R. Ponalagusamy; S. Senthilkumar
2009-01-01
A new Runge-Kutta (PK) fourth order with four stages embedded method with error control is presented in this paper for raster simulation in cellular neural network (CNN) environment. Through versatile algorithm, single layer/raster CNN array is implemented by incorporating the proposed technique. Simulation results have been obtained, and comparison has also been carried out to show the efficiency of the proposed numerical integration algorithm. The analytic expressions for local truncation error and global truncation error are derived. It is seen that the RK-embedded root mean square outperforms the RK-embedded Heronian mean and RK-embedded harmonic mean.
The mass of the {delta} resonance in a finite volume: fourth-order calculations
Energy Technology Data Exchange (ETDEWEB)
Hoja, Dominik; Rusetsky, Akaki [Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie), Universitaet Bonn (Germany); Bethe Center for Theoretical Physics, Universitaet Bonn (Germany); Bernard, Veronique [Universite Louis Pasteur, Laboratoire de Physique Theorique (Germany); Meissner, Ulf G. [Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie), Universitaet Bonn (Germany); Bethe Center for Theoretical Physics, Universitaet Bonn (Germany); Institut fuer Kernphysik und Juelich Center for Hadron Physics, Forschungszentrum Juelich (Germany)
2009-07-01
The self-energy of the {delta} resonance in a finite volume is calculated by using chiral effective field theory with explicit spin-3/2 fields. The calculations are performed up-to-and-including fourth order in the small scale expansion and yield an explicit parameterization of the energy spectrum of the interacting {pi}N pair in a finite box in terms of both the quark mass and the box size L. We show that finite-volume corrections are sizable at small quark masses. The values of certain low-energy constants are extracted from fitting to the available data in lattice QCD.
Institute of Scientific and Technical Information of China (English)
Shuo Zhang; Ming Wang
2008-01-01
In this paper,we consider the nonconforming finite element approximations of fourth order elliptic perturbation problems in two dimensions.We present an a posteriori error estimator under certain conditions,and give an h-version adaptive algorithm based on the error estimation.The local behavior of the estimator is analyzed as well.This estimator works for several nonconforming methods,such as the modified Morley method and the modified Zienkiewicz method,and under some assumptions,it is an optimal one.Numerical examples are reported.with a linear stationary Cahn-Hilliard-type equation as a model problem.
Image Denoising based on Fourth-Order Partial Differential Equations: A Survey
Directory of Open Access Journals (Sweden)
Anand Swaroop Khare
2013-03-01
Full Text Available Reduction of noise is essential especially in the field of image processing. Several researchers are continuously working in this direction and provide some good insights, but still there are lot of scope in this field. Noise mixed with image is harmful for image processing. In this paper we survey several aspects of image denoising and fourth-order partial differential equation. We also discuss several traditional methodology used with their advantages and disadvantages. We also provide a deep analysis based on the literature work from the previous research.
Fang, L.; Zhang, Y. J.; Fang, J.; Zhu, Y.
2016-08-01
We show by direct numerical simulations (DNSs) that in different types of isotropic turbulence, the fourth-order statistical invariants have approximately a linear relation, which can be represented by a straight line in the phase plane, passing two extreme states: the Gaussian state and the restricted Euler state. Also, each DNS case corresponds to an equilibrium region that is roughly Reynolds-dependent. In addition, both the time reversal and the compressibility effect lead to nonequilibrium transition processes in this phase plane. This observation adds a new restriction on the mean-field theory.
Hsu, Jong-Ping
2014-02-01
A generalization of the usual gauge symmetry leads to fourth-order gauge field equations, which imply a new constant force independent of distances. The force associated with the new U1 gauge symmetry is repulsive among baryons. Such a constant force based on baryon charge conservation gives a field-theoretic understanding of the accelerated cosmic expansion in the observable portion of the universe dominated by baryon galaxies. In consistent with all conservation laws and known forces, a simple rotating "dumbbell model" of the universe is briefly discussed.
Nuclear axial current operators to fourth order in chiral effective field theory
Krebs, H; Meißner, U -G
2016-01-01
We present the complete derivation of the nuclear axial charge and current operators as well as the pseudoscalar operators to fourth order in the chiral expansion relative to the dominant one-body contribution using the method of unitary transformation. We demonstrate that the unitary ambiguity in the resulting operators can be eliminated by the requirement of renormalizability and by matching of the pion-pole contributions to the nuclear forces. We give expressions for the renormalized single-, two- and three-nucleon contributions to the charge and current operators and pseudoscalar operators including the relevant relativistic corrections. We also verify explicitly the validity of the continuity equation.
Hsu, Jong-Ping
2014-01-01
A generalization of the usual gauge symmetry leads to fourth-order gauge field equations, which imply a new constant force independent of distances. The force associated with the new $U_1$ gauge symmetry is repulsive among baryons. Such a constant force based on baryon charge conservation gives a field-theoretic understanding of the accelerated cosmic-expansion in the observable portion of the universe dominated by baryon galaxies. In consistent with all conservation laws and known forces, a simple rotating `dumbbell model' of the universe is briefly discussed.
EXISTENCE AND MULTIPLICITY OF POSITIVE SOLUTIONS FOR A FOURTH-ORDER P-LAPLACE EQUATIONS
Institute of Scientific and Technical Information of China (English)
白占兵
2001-01-01
The solvability of one dimensional fourth-order p-Laplace equations of the type(g(u″))″+λa(t)f(u)=0, 0＜t＜1,u(0)=u(1)=u″(0)=u″(1)=0,where, g(v):= |v|p-2 v, p ＞ 1 is investigated. With cone compression/extension theorem, some existence and multiplicity results of positive solution have been required according to different growth condition of nonlinear form fat zero and at infinity.
Directory of Open Access Journals (Sweden)
Javad Faiz
2011-01-01
Full Text Available A UPS inverter operates in wide load impedance ranges from resistive to capacitive or inductive load. At the same time, fast transient load response, good load regulation and good switching frequency suppression is required. The variation of the load impedance changes the filter transfer characteristic and thus the output voltage value. In this paper, an analysis and simulation of the single phase voltage source uninterruptible power supply (UPS with fourth order filter (multiple-filter in output inverter, based on the state space averaging and small signal linearization technique, is proposed. The simulation results show the high quality sinusoidal output voltage at different loads, with THD less than %5.
Some existence results for a fourth order equation involving critical exponent
Ben-Ayed, M; Hammami, M
2003-01-01
In this paper a fourth order equation involving critical growth is considered under the Navier boundary condition: DELTA sup 2 u = Ku sup p , u > 0 in OMEGA, u = DELTA u = 0 on partial deriv OMEGA, where K is a positive function, OMEGA is a bounded smooth domain in R sup n , n >= 5 and p + 1 2n/(n - 4) is the critical Sobolev exponent. We give some topological conditions on K to ensure the existence of solutions. Our methods involve the study of the critical points at infinity and their contribution to the topology of the level sets of the associated Euler Lagrange functional.
Positive solutions with changing sign energy to a nonhomogeneous elliptic problem of fourth order
Directory of Open Access Journals (Sweden)
M.Talbi
2011-01-01
Full Text Available In this paper, we study the existence for two positive solutions toa nonhomogeneous elliptic equation of fourth order with a parameter lambda such tha 0 < lambda < lambda^. The first solution has a negative energy while the energy of the second one is positive for 0 < lambda < lambda_0 and negative for lambda_0 < lambda < lambda^. The values lambda_0 and lambda^ are given under variational form and we show that every corresponding critical point is solution of the nonlinear elliptic problem (with a suitable multiplicative term.
Directory of Open Access Journals (Sweden)
Yunjiao Bai
2015-01-01
Full Text Available The traditional fourth-order nonlinear diffusion denoising model suffers the isolated speckles and the loss of fine details in the processed image. For this reason, a new fourth-order partial differential equation based on the patch similarity modulus and the difference curvature is proposed for image denoising. First, based on the intensity similarity of neighbor pixels, this paper presents a new edge indicator called patch similarity modulus, which is strongly robust to noise. Furthermore, the difference curvature which can effectively distinguish between edges and noise is incorporated into the denoising algorithm to determine the diffusion process by adaptively adjusting the size of the diffusion coefficient. The experimental results show that the proposed algorithm can not only preserve edges and texture details, but also avoid isolated speckles and staircase effect while filtering out noise. And the proposed algorithm has a better performance for the images with abundant details. Additionally, the subjective visual quality and objective evaluation index of the denoised image obtained by the proposed algorithm are higher than the ones from the related methods.
On the Schrodinger equations with isotropic and anisotropic fourth-order dispersion
Directory of Open Access Journals (Sweden)
Elder J. Villamizar-Roa
2016-01-01
Full Text Available This article concerns the Cauchy problem associated with the nonlinear fourth-order Schrodinger equation with isotropic and anisotropic mixed dispersion. This model is given by the equation $$ i\\partial_tu+\\epsilon \\Delta u+\\delta A u+\\lambda|u|^\\alpha u=0,\\quad x\\in\\mathbb{R}^{n},\\; t\\in \\mathbb{R}, $$ where A is either the operator $\\Delta^2$ (isotropic dispersion or $\\sum_{i=1}^d\\partial_{x_ix_ix_ix_i}$, $1\\leq d
Conservative fourth-order time integration of non-linear dynamic systems
DEFF Research Database (Denmark)
Krenk, Steen
2015-01-01
An energy conserving time integration algorithm with fourth-order accuracy is developed for dynamic systems with nonlinear stiffness. The discrete formulation is derived by integrating the differential state-space equations of motion over the integration time increment, and then evaluating the re...... integration of oscillatory systems with only a few integration points per period. Three numerical examples demonstrate the high accuracy of the algorithm. (C) 2015 Elsevier B.V. All rights reserved.......An energy conserving time integration algorithm with fourth-order accuracy is developed for dynamic systems with nonlinear stiffness. The discrete formulation is derived by integrating the differential state-space equations of motion over the integration time increment, and then evaluating...... the resulting time integrals of the inertia and stiffness terms via integration by parts. This process introduces the time derivatives of the state space variables, and these are then substituted from the original state-space differential equations. The resulting discrete form of the state-space equations...
Wang, Rui; Chen, Lie-Wen
2017-10-01
We establish a relation between the equation of state of nuclear matter and the fourth-order symmetry energy asym,4 (A) of finite nuclei in a semi-empirical nuclear mass formula by self-consistently considering the bulk, surface and Coulomb contributions to the nuclear mass. Such a relation allows us to extract information on nuclear matter fourth-order symmetry energy Esym,4 (ρ0) at normal nuclear density ρ0 from analyzing nuclear mass data. Based on the recent precise extraction of asym,4 (A) via the double difference of the ;experimental; symmetry energy extracted from nuclear masses, for the first time, we estimate a value of Esym,4 (ρ0) = 20.0 ± 4.6 MeV. Such a value of Esym,4 (ρ0) is significantly larger than the predictions from mean-field models and thus suggests the importance of considering the effects of beyond the mean-field approximation in nuclear matter calculations.
Fourth-Order Method for Numerical Integration of Age- and Size-Structured Population Models
Energy Technology Data Exchange (ETDEWEB)
Iannelli, M; Kostova, T; Milner, F A
2008-01-08
In many applications of age- and size-structured population models, there is an interest in obtaining good approximations of total population numbers rather than of their densities. Therefore, it is reasonable in such cases to solve numerically not the PDE model equations themselves, but rather their integral equivalents. For this purpose quadrature formulae are used in place of the integrals. Because quadratures can be designed with any order of accuracy, one can obtain numerical approximations of the solutions with very fast convergence. In this article, we present a general framework and a specific example of a fourth-order method based on composite Newton-Cotes quadratures for a size-structured population model.
Directory of Open Access Journals (Sweden)
Mabrouk Briki
2016-05-01
Full Text Available In this paper, a fourth-order boundary value problem on the half-line is considered and existence of solutions is proved using a minimization principle and the mountain pass theorem.
Institute of Scientific and Technical Information of China (English)
文双春; 钱列加; 范滇元
2003-01-01
A new method for generation of a train of ultrashort pulses or a sequence of ultrashort light bullets is proposed.This method is based on the fourth-order dispersion-dependent spatiotemporal instability in dispersive Kerr media. The repetition-rate of the generated bullets can be made quite large by increasing the corresponding spatial modulation frequency locating in the new instability region resulted from fourth-order dispersion.
Killing Two Birds with the Same Stone. Higher Order Skills Embedded in E-teaching Strategies
Directory of Open Access Journals (Sweden)
Monica Giuchici
2011-11-01
Full Text Available Meta-cognitive skills have become a sine qua non in any 21st century teaching approach from primary, lower- and upper-secondary education, tertiary or university level. Whilst the traditional recipe of instruction based on “what to teach” has consumed so much effort, time, and energies meant at transmitting and acquiring knowledge, little or no attention has been allotted to higher-order skills which, once embedded in a curriculum and further-on released within a teaching-learning-evaluating paradigm, could make a qualitative difference. This paper aims at providing a scaffolding strategy of launching a blended learning curriculum online,as any specialist in education would love to “kill two birds with the same stone”.
A Fourth-Order Modified Method for the Cauchy Problem of the Modified Helmholtz Equation
Institute of Scientific and Technical Information of China (English)
R. Shi; H. H. Qin
2009-01-01
This paper is concerned with the Cauchy problem for the modified Helmholtz equation in an infinite strip domain 0 < x≤ 1, y ∈ R. The Cauchy data at x = 0 is given and the solution is then sought for the interval 0 < x ≤1. This problem is highly ill-posed and the solution (if it exists) does not depend continuously on the given data. In this paper, we propose a fourth-order modified method to solve the Cauchy problem. Convergence estimates are presented under the suitable choices of regularization parameters and the a priori assumption on the bounds of the exact solution. Numerical implementation is considered and the numerical examples show that our proposed method is effective and stable.
A class of the fourth order finite volume Hermite weighted essentially non-oscillatory schemes
Institute of Scientific and Technical Information of China (English)
2008-01-01
In this paper,we developed a class of the fourth order accurate finite volume Hermite weighted essentially non-oscillatory(HWENO)schemes based on the work(Computers&Fluids,34:642-663(2005))by Qiu and Shu,with Total Variation Diminishing Runge-Kutta time discretization method for the two-dimensional hyperbolic conservation laws.The key idea of HWENO is to evolve both with the solution and its derivative,which allows for using Hermite interpolation in the reconstruction phase,resulting in a more compact stencil at the expense of the additional work.The main difference between this work and the formal one is the procedure to reconstruct the derivative terms.Comparing with the original HWENO schemes of Qiu and Shu,one major advantage of new HWENOschemes is its robust in computation of problem with strong shocks.Extensive numerical experiments are performed to illustrate the capability of the method.
Pure perceptual-based learning of second-, third-, and fourth-order sequential probabilities.
Remillard, Gilbert
2011-07-01
There is evidence that sequence learning in the traditional serial reaction time task (SRTT), where target location is the response dimension, and sequence learning in the perceptual SRTT, where target location is not the response dimension, are handled by different mechanisms. The ability of the latter mechanism to learn sequential contingencies that can be learned by the former mechanism was examined. Prior research has established that people can learn second-, third-, and fourth-order probabilities in the traditional SRTT. The present study reveals that people can learn such probabilities in the perceptual SRTT. This suggests that the two mechanisms may have similar architectures. A possible neural basis of the two mechanisms is discussed.
A fourth-order indirect integration method for black hole perturbations: even modes
Energy Technology Data Exchange (ETDEWEB)
Ritter, Patxi; Spallicci, Alessandro D A M [Universite d' Orleans, Observatoire des Sciences de l' Univers en region Centre, LPC2E Campus CNRS, 3A Av. Recherche Scientifique, 45071 Orleans (France); Aoudia, Sofiane [Max Planck Institut fuer Gravitationphysik, A Einstein, Am Muehlenberg 1, 14476 Potsdam (Germany); Cordier, Stephane, E-mail: spallicci@cnrs-orleans.fr [Universite d' Orleans, Laboratoire de Mathematiques-Analyse, Probabilites, Modelisation-Orleans, MAPMO, Rue de Chartres, 45067 Orleans (France)
2011-07-07
On the basis of a recently proposed strategy of finite element integration in time domain for partial differential equations with a singular source term, we present a fourth-order algorithm for non-rotating black hole perturbations in the Regge-Wheeler gauge. Herein, we address even perturbations induced by a particle plunging in. The forward time value at the upper node of the (r*, t) grid cell is obtained by an algebraic sum of (i) the preceding node values of the same cell, (ii) analytic expressions, related to the jump conditions on the wavefunction and its derivatives and (iii) the values of the wavefunction at adjacent cells. In this approach, the numerical integration does not deal with the source and potential terms directly, for cells crossed by the particle world line. This scheme has also been applied to circular and eccentric orbits and it will be the object of a forthcoming publication.
Effect of third- and fourth-order moments on the modeling of Unresolved Transition Arrays
Pain, Jean-Christophe; Bauche, Jacques; Bauche-Arnoult, Claire
2009-01-01
The impact of the third (skewness) and fourth (kurtosis) reduced centered moments on the statistical modeling of E1 lines in complex atomic spectra is investigated through the use of Gram-Charlier, Normal Inverse Gaussian and Generalized Gaussian distributions. It is shown that the modeling of unresolved transition arrays with non-Gaussian distributions may reveal more detailed structures, due essentially to the large value of the kurtosis. In the present work, focus is put essentially on the Generalized Gaussian, the power of the argument in the exponential being constrained by the kurtosis value. The relevance of the new statistical line distribution is checked by comparisons with smoothed detailed line-by-line calculations and through the analysis of 2p-3d transitions of recent laser or Z-pinch absorption measurements. The issue of calculating high-order moments is also discussed (Racah algebra, Jucys graphical method, semi-empirical approach ...).
The feature extraction of ship radiated noise with Fourth Order Cumulant diagonal slice
Institute of Scientific and Technical Information of China (English)
FAN Yangyu; SUN Jincai; HAO Chongyang; LI Ya'an
2004-01-01
After analyzed Fourth Order Cumulant (FOC) of harmonic signals theoretically, the FOC is divided into three parts. The first is the cubic frequency (phase) coupling components.The second is the double frequency (phase) coupling components (ω1 + ω2 = ω3 + ω4). The last is the rest components. On the basis of the study, the FOC diagonal slice is used to extract the cubic frequency (phase) coupling feature, double frequency (phase) coupling feature and the "sub-band energy" feature of ship-radiated noise. In terms of the fea tures, the three type ships are classified by artificial neural network. The correct classification rates of A, B and C ships are 92.5%, 92.7%, 88.6%, respectively. The results show the method is effective and practical.
Fourth-order analysis of a diffusive lattice Boltzmann method for barrier coatings.
Strand, Kyle T; Feickert, Aaron J; Wagner, Alexander J
2017-06-01
We examine the applicability of diffusive lattice Boltzmann methods to simulate the fluid transport through barrier coatings, finding excellent agreement between simulations and analytical predictions for standard parameter choices. To examine more interesting non-Fickian behavior and multiple layers of different coatings, it becomes necessary to explore a wider range of parameters. However, such a range of parameters exposes deficiencies in such an implementation. To investigate these discrepancies, we examine the form of higher-order terms in the hydrodynamic limit of our lattice Boltzmann method. We identify these corrections to fourth order and validate these predictions with high accuracy. However, it is observed that the validated correction terms do not fully explain the bulk of observed error. This error was instead caused by the standard finite boundary conditions for the contact of the coating with the imposed environment. We identify a self-consistent form of these boundary conditions for which these errors are dramatically reduced. The instantaneous switching used as a boundary condition for the barrier problem proves demanding enough that any higher-order corrections meaningfully contribute for a small range of parameters. There is a large parameter space where the agreement between simulations and analytical predictions even in the second-order form are below 0.1%, making further improvements to the algorithm unnecessary for such an application.
On the Beam Functions Spectral Expansions for Fourth-Order Boundary Value Problems
Papanicolaou, N. C.; Christov, C. I.
2007-10-01
In this paper we develop further the Galerkin technique based on the so-called beam functions with application to nonlinear problems. We make use of the formulas expressing a product of two beam functions into a series with respect to the system. First we prove that the overall convergence rate for a fourth-order linear b.v.p is algebraic fifth order, provided that the derivatives of the sought function up to fifth order exist. It is then shown that the inclusion of a quadratic nonlinear term in the equation does not degrade the fifth-order convergence. We validate our findings on a model problem which possesses analytical solution in the linear case. The agreement between the beam-Galerkin solution and the analytical solution for the linear problem is better than 10-12 for 200 terms. We also show that the error introduced by the expansion of the nonlinear term is lesser than 10-9. The beam-Galerkin method outperforms finite differences due to its superior accuracy whilst its advantage over the Chebyshev-tau method is attributed to the smaller condition number of the matrices involved in the former.
Nuclear matter fourth-order symmetry energy in relativistic mean field models
Cai, Bao-Jun
2011-01-01
Within the nonlinear relativistic mean field model, we derive the analytical expression of the nuclear matter fourth-order symmetry energy $E_{4}(\\rho)$. Our results show that the value of $E_{4}(\\rho)$ at normal nuclear matter density $\\rho_{0}$ is generally less than 1 MeV, confirming the empirical parabolic approximation to the equation of state for asymmetric nuclear matter at $\\rho_{0}$. On the other hand, we find that the $E_{4}(\\rho)$ may become nonnegligible at high densities. Furthermore, the analytical form of the $E_{4}(\\rho)$ provides the possibility to study the higher-order effects on the isobaric incompressibility of asymmetric nuclear matter, i.e., $K_{\\mathrm{sat}}(\\delta)=K_{0}+K_{\\mathrm{{sat},2}}\\delta ^{2}+K_{\\mathrm{{sat},4}}\\delta ^{4}+\\mathcal{O}(\\delta ^{6})$ where $\\delta =(\\rho_{n}-\\rho_{p})/\\rho $ is the isospin asymmetry, and we find that the value of $K_{\\mathrm{{sat},4}}$ is generally comparable with that of the $K_{\\mathrm{{sat},2}}$. In addition, we study the effects of the $E...
Institute of Scientific and Technical Information of China (English)
Ao Sheng-Mei; Yan Jia-Ren; Yu Hui-You
2007-01-01
We solve the generalized nonlinear Schrodinger equation describing the propagation of femtosecond pulses in a nonlinear optical fibre with higher-order dispersions by using the direct approach to perturbation for bright solitons, and discuss the combined effects of the third- and fourth-order dispersions on velocity, temporal intensity distribution and peak intensity of femtosecond pulses. It is noticeable that the combined effects of the third- and fourth-order dispersions on an initial propagated soliton can partially compensate each other, which seems to be significant for the stability controlling of soliton propagation features.
Multiple solutions for fourth order elliptic problems with p(x-biharmonic operators
Directory of Open Access Journals (Sweden)
Lingju Kong
2016-01-01
Full Text Available We study the multiplicity of weak solutions to the following fourth order nonlinear elliptic problem with a \\(p(x\\-biharmonic operator \\[\\begin{cases}\\Delta^2_{p(x}u+a(x|u|^{p(x-2}u=\\lambda f(x,u\\quad\\text{ in }\\Omega,\\\\ u=\\Delta u=0\\quad\\text{ on }\\partial\\Omega,\\end{cases}\\] where \\(\\Omega\\ is a smooth bounded domain in \\(\\mathbb{R}^N\\, \\(p\\in C(\\overline{\\Omega}\\, \\(\\Delta^2_{p(x}u=\\Delta(|\\Delta u|^{p(x-2}\\Delta u\\ is the \\(p(x\\-biharmonic operator, and \\(\\lambda\\gt 0\\ is a parameter. We establish sufficient conditions under which there exists a positive number \\(\\lambda^{*}\\ such that the above problem has at least two nontrivial weak solutions for each \\(\\lambda\\gt\\lambda^{*}\\. Our analysis mainly relies on variational arguments based on the mountain pass lemma and some recent theory on the generalized Lebesgue-Sobolev spaces \\(L^{p(x}(\\Omega\\ and \\(W^{k,p(x}(\\Omega\\.
Long-time coherence in fourth-order spin correlation functions
Fröhling, Nina; Anders, Frithjof B.
2017-07-01
We study the long-time decay of fourth-order electron spin correlation functions for an isolated singly charged semiconductor quantum dot. The electron spin dynamics is governed by the applied external magnetic field as well as the hyperfine interaction. While the long-time coherent oscillations in the correlation functions can be understood within a semiclassical approach treating the Overhauser field as frozen, the field dependent decay of its amplitude reported in different experiments cannot be explained by the central-spin model indicating the insufficiency of such a description. By incorporating the nuclear Zeeman splitting and the strain induced nuclear-electric quadrupolar interaction, we find the correct crossover from a fast decay in small magnetic fields to a slow exponential asymptotic in large magnetic fields. It originates from a competition between the quadrupolar interaction inducing an enhanced spin decay and the nuclear Zeeman term that suppressed the spin-flip processes. We are able to explain the magnetic field dependency of the characteristic long-time decay time T2 depending on the experimental setups. The calculated asymptotic values of T2=3 -4 μ s agree qualitatively well with the experimental data.
50 CFR 21.42 - Authority to issue depredating orders to permit the killing of migratory game birds.
2010-10-01
... permit the killing of migratory game birds. 21.42 Section 21.42 Wildlife and Fisheries UNITED STATES FISH..., PURCHASE, BARTER, EXPORTATION, AND IMPORTATION OF WILDLIFE AND PLANTS (CONTINUED) MIGRATORY BIRD PERMITS Control of Depredating and Otherwise Injurious Birds § 21.42 Authority to issue depredating orders...
Fourth-Order Contour Mode ZnO-on-SOI Disk Resonators for Mass Sensing Applications
Directory of Open Access Journals (Sweden)
Ivan Rivera
2015-04-01
Full Text Available In this work, we have investigated the design, fabrication and testing of ZnO-on-SOI fourth-order contour mode disk resonators for mass sensing applications. This study aims to unveil the possibility for real-time practical mass sensing applications by using high-Q ZnO-on-SOI contour-mode resonators while taking into account their unique modal characteristics. Through focused ion beam (FIB direct-write metal deposition techniques, the effects of localized mass loading on the surface of three extensional mode devices have been investigated. Ten microfabricated 40 mm-radius disk resonators, which all have a 20 mm-thick silicon device layer and 1 mm-thick ZnO transducer layer but varied anchor widths and numbers, have exhibited resonant frequencies ranging from 84.9 MHz to 86.7 MHz with Q factors exceeding 6000 (in air and 10,000 (in vacuum, respectively. It has been found that the added mass at the nodal locations leads to noticeable Q-factor degradation along with lower induced frequency drift, thereby resulting in reduced mass sensitivity. All three measured devices have shown a mass sensitivity of ~1.17 Hz·fg−1 at the maximum displacement points with less than 33.3 ppm of deviation in term of fractional frequency change. This mass sensitivity is significantly higher than 0.334 Hz·fg−1 at the nodal points. Moreover, the limit of detection (LOD for this resonant mass sensor was determined to be 367 ag and 1290 ag (1 ag = 10−18 g for loaded mass at the maximum and minimum displacement points, accordingly.
Constantin, Lucian A; Fabiano, Eduardo; Della Sala, Fabio
2017-09-12
Using the semiclassical neutral atom theory, we developed a modified fourth-order kinetic energy (KE) gradient expansion (GE4m) that keeps unchanged all the linear-response terms of the uniform electron gas and gives a significant improvement with respect to the known semilocal functionals for both large atoms and jellium surfaces. On the other hand, GE4m is not accurate for light atoms; thus, we modified the GE4m coefficients making them dependent on a novel ingredient, the reduced Hartree potential, recently introduced in the Journal of Chemical Physics 2016, 145, 084110, in the context of exchange functionals. The resulting KE gradient expansion functional, named uGE4m, belongs to the novel class of u-meta-generalized-gradient-approximations (uMGGA) whose members depend on the conventional ingredients (i.e., the reduced gradient and Laplacian of the density) as well as on the reduced Hartree potential. To test uGE4m, we defined an appropriate benchmark (including total KE and KE differences for atoms, molecules and jellium clusters) for gradient expansion functionals, that is, including only those systems which are mainly described by a slowly varying density regime. While most of the GGA and meta-GGA KE functionals (we tested 18 of them) are accurate for some properties and inaccurate for others, uGE4m shows a consistently good performance for all the properties considered. This represents a qualitative boost in the KE functional development and highlights the importance of the reduced Hartree potential for the construction of next-generation KE functionals.
Institute of Scientific and Technical Information of China (English)
WANG Xue-bin
2007-01-01
To consider the effects of the interactions and interplay among microstructures, gradient-dependent models of second- and fourth-order are included in the widely used phenomenological Johnson-Cook model where the effects of strain-hardening, strain rate sensitivity, and thermal-softening are successfully described. The various parameters for 1006 steel, 4340 steel and S-7 tool steel are assigned. The distributions and evolutions of the local plastic shear strain and deformation in adiabatic shear band (ASB) are predicted. The calculated results of the second- and fourth-order gradient plasticity models are compared. S-7 tool steel possesses the steepest profile of local plastic shear strain in ASB, whereas 1006 steel has the least profile. The peak local plastic shear strain in ASB for S-7 tool steel is slightly higher than that for 4340 steel and is higher than that for 1006 steel. The extent of the nonlinear distribution of the local plastic shear deformation in ASB is more apparent for the S-7 tool steel, whereas it is the least apparent for 1006 steel. In fourth-order gradient plasticity model, the profile of the local plastic shear strain in the middle of ASB has a pronounced plateau whose width decreases with increasing average plastic shear strain, leading to a shrink of the portion of linear distribution of the profile of the local plastic shear deformation. When compared with the second-order gradient plasticity model, the fourth-order gradient plasticity model shows a lower peak local plastic shear strain in ASB and a higher magnitude of plastic shear deformation at the top or base of ASB, which is due to wider ASB. The present numerical results of the second- and fourth-order gradient plasticity models are consistent with the previous numerical and experimental results at least qualitatively.
Li, Y.; Han, B.; Métivier, L.; Brossier, R.
2016-09-01
We investigate an optimal fourth-order staggered-grid finite-difference scheme for 3D frequency-domain viscoelastic wave modeling. An anti-lumped mass strategy is incorporated to minimize the numerical dispersion. The optimal finite-difference coefficients and the mass weighting coefficients are obtained by minimizing the misfit between the normalized phase velocities and the unity. An iterative damped least-squares method, the Levenberg-Marquardt algorithm, is utilized for the optimization. Dispersion analysis shows that the optimal fourth-order scheme presents less grid dispersion and anisotropy than the conventional fourth-order scheme with respect to different Poisson's ratios. Moreover, only 3.7 grid-points per minimum shear wavelength are required to keep the error of the group velocities below 1%. The memory cost is then greatly reduced due to a coarser sampling. A parallel iterative method named CARP-CG is used to solve the large ill-conditioned linear system for the frequency-domain modeling. Validations are conducted with respect to both the analytic viscoacoustic and viscoelastic solutions. Compared with the conventional fourth-order scheme, the optimal scheme generates wavefields having smaller error under the same discretization setups. Profiles of the wavefields are presented to confirm better agreement between the optimal results and the analytic solutions.
Steijl, R.; Hoeijmakers, H.W.M.
2004-01-01
A fourth-order accurate solution method for the three-dimensional Helmholtz equations is described that is based on a compact finite-difference stencil for the Laplace operator. Similar discretization methods for the Poisson equation have been presented by various researchers for Dirichlet boundary
Institute of Scientific and Technical Information of China (English)
Wang Hua; Alatancang; Huang Jun-Jie
2011-01-01
In this paper,we consider the eigenvalue problem of a class of fourth-order operator matrices appearing in mechanics,including the geometric multiplicity,algebraic index,and algebraic multiplicity of the eigenvalue,the symplectic orthogonality,and completeness of eigen and root vector systems.The obtained results are applied to the plate bending problem.
Guha, Partha; Ghose Choudhury, A.; Khanra, Barun
2012-11-01
We introduce a new transformation (nonlocal) to find the general solutions of some equations belonging to the third and fourth-order time dependent Riccati class of equations. These are in turn related to the Chazy polynomial class and the time dependent F-XVI Bureau symbol PI equations respectively.
DEFF Research Database (Denmark)
Agger, Gunhild
2013-01-01
This article tracks the uncanny locations of The Killing (2007–2012), relating them to place, space and atmosphere, putting bits and pieces from the topographic puzzle together with cues from the symbolic space in order to see how they fit into the overall pattern of Nordic Noir. In The Killing, ...
Directory of Open Access Journals (Sweden)
L. Jones Tarcius Doss
2012-01-01
Full Text Available A quadrature-based mixed Petrov-Galerkin finite element method is applied to a fourth-order linear ordinary differential equation. After employing a splitting technique, a cubic spline trial space and a piecewise linear test space are considered in the method. The integrals are then replaced by the Gauss quadrature rule in the formulation itself. Optimal order a priori error estimates are obtained without any restriction on the mesh.
Aoyama, T; Kinoshita, T; Nio, M
2011-01-01
This paper reports the tenth-order contributions to the g-2 of the electron a_e and those of the muon a_mu from the gauge-invariant Set II(c), which consists of 36 Feynman diagrams, and Set II(d), which consists of 180 Feynman diagrams. Both sets are obtained by insertion of sixth-order vacuum-polarization diagrams in the fourth-order anomalous magnetic moment. The mass-independent contributions from Set II(c) and Set II(d) are -0.116 489 (32)(alpha/pi)^5 and -0.243 00 (29)(alpha/pi)^5, respectively. The leading contributions to a_mu, which involve electron loops only, are -3.888 27 (90)(alpha/pi)^5 and 0.4972 (65)(alpha/pi)^5 for Set II(c) and Set II(d), respectively. The total contributions of the electron, muon, and tau-lepton loops to a_e are -0.116 874 (32) (alpha/pi)^5 for Set II(c) and -0.243 10 (29) (alpha/pi)^5 for Set II(d). The contributions of electron, muon, and tau-lepton loops to a_mu are -5.5594 (11) (alpha/pi)^5 for Set II(c) and 0.2465 (65) (alpha/pi)^5 for Set II(d).
Aoyama, T; Kinoshita, T; Nio, M
2010-01-01
This paper reports the tenth-order QED contribution to lepton g-2 from diagrams of three gauge-invariant sets VI(d), VI(g), and VI(h), which are obtained by including various fourth-order radiative corrections to the sixth-order g-2 containing light-by-light-scattering subdiagrams. In the case of electron g-2, they consist of 492, 480, and 630 vertex Feynman diagrams, respectively. The results of numerical integration, including mass-dependent terms containing muon loops, are 1.8418(95) (alpha/pi)^5 for the Set VI(d), -1.5918(65) (alpha/pi)^5 for the Set VI(g), and 0.1797(40) (alpha/pi)^5 for the Set VI(h), respectively. We also report the contributions to the muon g-2, which derive from diagrams containing an electron, muon or tau lepton loop: Their sums are -5.876(802) (alpha/pi)^5 for the Set VI(d), 5.710(490) (alpha/pi)^5 for the Set VI(g), and -8.361(232) (alpha/pi)^5 for the Set VI(h), respectively.
Majorosi, Szilárd; Czirják, Attila
2016-11-01
We present a novel numerical method and algorithm for the solution of the 3D axially symmetric time-dependent Schrödinger equation in cylindrical coordinates, involving singular Coulomb potential terms besides a smooth time-dependent potential. We use fourth order finite difference real space discretization, with special formulae for the arising Neumann and Robin boundary conditions along the symmetry axis. Our propagation algorithm is based on merging the method of the split-operator approximation of the exponential operator with the implicit equations of second order cylindrical 2D Crank-Nicolson scheme. We call this method hybrid splitting scheme because it inherits both the speed of the split step finite difference schemes and the robustness of the full Crank-Nicolson scheme. Based on a thorough error analysis, we verified both the fourth order accuracy of the spatial discretization in the optimal spatial step size range, and the fourth order scaling with the time step in the case of proper high order expressions of the split-operator. We demonstrate the performance and high accuracy of our hybrid splitting scheme by simulating optical tunneling from a hydrogen atom due to a few-cycle laser pulse with linear polarization.
Majorosi, Szilárd
2016-01-01
We present a novel numerical method and algorithm for the solution of the 3D axially symmetric time-dependent Schr\\"odinger equation in cylindrical coordinates, involving singular Coulomb potential terms besides a smooth time-dependent potential. We use fourth order finite difference real space discretization, with special formulae for the arising Neumann and Robin boundary conditions along the symmetry axis. Our propagation algorithm is based on merging the method of the split-operator approximation of the exponential operator with the implicit equations of second order cylindrical 2D Crank-Nicolson scheme. We call this method hybrid splitting scheme because it inherits both the speed of the split step finite difference schemes and the robustness of the full Crank-Nicolson scheme. Based on a thorough error analysis, we verified both the fourth order accuracy of the spatial discretization in the optimal spatial step size range, and the fourth order scaling with the time step in the case of proper high order e...
Kamibayashi, Yuki; Miura, Shinichi
2016-08-01
In the present study, variational path integral molecular dynamics and associated hybrid Monte Carlo (HMC) methods have been developed on the basis of a fourth order approximation of a density operator. To reveal various parameter dependence of physical quantities, we analytically solve one dimensional harmonic oscillators by the variational path integral; as a byproduct, we obtain the analytical expression of the discretized density matrix using the fourth order approximation for the oscillators. Then, we apply our methods to realistic systems like a water molecule and a para-hydrogen cluster. In the HMC, we adopt two level description to avoid the time consuming Hessian evaluation. For the systems examined in this paper, the HMC method is found to be about three times more efficient than the molecular dynamics method if appropriate HMC parameters are adopted; the advantage of the HMC method is suggested to be more evident for systems described by many body interaction.
Institute of Scientific and Technical Information of China (English)
ZHANG Yu-chuan; ZHOU Zong-fu
2014-01-01
In this work, we investigate the following fourth-order delay differential equation of boundary value problem with p-Laplacian(Φp(u000))0(t)+a(t)f(t, u(t−τ), u0(t))=0, 0
Vibratory motion of fourth order fluid film over a unsteady heated flat
Mohmand, Muhammad Ismail; Mamat, Mustafa Bin; Shah, Qayyum; Gul, Taza
2017-03-01
Analysis of heat transfer is studied in magnetohydrodynamic (MHD) thin layer flow of an unsteady fourth grade fluid past a moving and oscillating vertical plate for lift and drainage problem. The governing equations are modelled in terms of nonlinear partial differential equations with some physical boundary conditions. Two different analytical methods, namely Adomian Decomposition Method (ADM) and the Optimal Homotopy Asymptotic Method (OHAM) are used for finding the series solution of the problem. The solutions obtained through two different techniques are compared using graphs and tables and found an excellent agreement. The variants of embedded flow parameters in the solution are analyzed through graphical illustrations.
Directory of Open Access Journals (Sweden)
Kasim Hussain
2015-01-01
Full Text Available We present two pairs of embedded Runge-Kutta type methods for direct solution of fourth-order ordinary differential equations (ODEs of the form y(iv=f(x,y denoted as RKFD methods. The first pair, which we will call RKFD5(4, has orders 5 and 4, and the second one has orders 6 and 5 and we will call it RKFD6(5. The techniques used in the derivation of the methods are that the higher order methods are very precise and the lower order methods give the best error estimate. Based on these pairs, we have developed variable step codes and we have used them to solve a set of special fourth-order problems. Numerical results show the robustness and the efficiency of the new RKFD pairs as compared with the well-known embedded Runge-Kutta pairs in the scientific literature after reducing the problems into a system of first-order ordinary differential equations (ODEs and solving them.
DEFF Research Database (Denmark)
Agger, Gunhild
2013-01-01
This article tracks the uncanny locations of The Killing (2007–2012), relating them to place, space and atmosphere, putting bits and pieces from the topographic puzzle together with cues from the symbolic space in order to see how they fit into the overall pattern of Nordic Noir. In The Killing......, the abstract level of space and atmosphere meets the concrete level of place, both influencing the notion of location. This meeting, I suggest, has contributed towards the simultaneous domestic and international appeal of The Killing....
Wongwathanarat, Annop; Müller, Ewald
2016-01-01
We present a new fourth-order finite-volume hydrodynamics code named Apsara. The code employs the high-order finite-volume method for mapped coordinates developed by Colella et al. (2011) with extensions for non-linear hyperbolic conservation laws by McCorquodale & Colella (2011) and Guzik et al. (2012). Using the mapped-grid technique Apsara can handle arbitrary structured curvilinear meshes in three spatial dimensions. The code has successfully passed several hydrodynamic test problems including the advection of a Gaussian density profile and a non-linear vortex, as well as the propagation of linear acoustic waves. For these test problems Apsara produces fourth-order accurate results in case of smooth grid mappings. The order of accuracy is reduced to first-order when using the non-smooth circular grid mapping of Calhoun et al. (2008). When applying the high-order method by McCorquodale & Colella (2011) to simulations of low-Mach number flows, e.g. the Gresho vortex and the Taylor-Green vortex, we d...
Wongwathanarat, A.; Grimm-Strele, H.; Müller, E.
2016-10-01
We present a new fourth-order, finite-volume hydrodynamics code named Apsara. The code employs a high-order, finite-volume method for mapped coordinates with extensions for nonlinear hyperbolic conservation laws. Apsara can handle arbitrary structured curvilinear meshes in three spatial dimensions. The code has successfully passed several hydrodynamic test problems, including the advection of a Gaussian density profile and a nonlinear vortex and the propagation of linear acoustic waves. For these test problems, Apsara produces fourth-order accurate results in case of smooth grid mappings. The order of accuracy is reduced to first-order when using the nonsmooth circular grid mapping. When applying the high-order method to simulations of low-Mach number flows, for example, the Gresho vortex and the Taylor-Green vortex, we discover that Apsara delivers superior results to codes based on the dimensionally split, piecewise parabolic method (PPM) widely used in astrophysics. Hence, Apsara is a suitable tool for simulating highly subsonic flows in astrophysics. In the first astrophysical application, we perform implicit large eddy simulations (ILES) of anisotropic turbulence in the context of core collapse supernova (CCSN) and obtain results similar to those previously reported.
Yamaleev, Nail K.; Carpenter, Mark H.
2017-02-01
High-order numerical methods that satisfy a discrete analog of the entropy inequality are uncommon. Indeed, no proofs of nonlinear entropy stability currently exist for high-order weighted essentially nonoscillatory (WENO) finite volume or weak-form finite element methods. Herein, a new family of fourth-order WENO spectral collocation schemes is developed, that are nonlinearly entropy stable for the one-dimensional compressible Navier-Stokes equations. Individual spectral elements are coupled using penalty type interface conditions. The resulting entropy stable WENO spectral collocation scheme achieves design order accuracy, maintains the WENO stencil biasing properties across element interfaces, and satisfies the summation-by-parts (SBP) operator convention, thereby ensuring nonlinear entropy stability in a diagonal norm. Numerical results demonstrating accuracy and nonoscillatory properties of the new scheme are presented for the one-dimensional Euler and Navier-Stokes equations for both continuous and discontinuous compressible flows.
Fourth-Order Splitting Methods for Time-Dependant Differential Equations
Institute of Scientific and Technical Information of China (English)
Jürgen Geiser
2008-01-01
This study was suggested by previous work on the simulation of evolution equations with scale-dependent processes, e.g., wave-propagation or heat-transfer, that are modeled by wave equations or heat equations. Here, we study both parabolic and hyperbolic equations. We focus on ADI (alternating direction implicit) methods and LOD (locally one-dimensional) methods, which are standard splitting methods of lower order, e.g. second-order. Our aim is to develop higher-order ADI methods, which are performed by Richardson extrapolation, Crank-Nicolson methods and higher-order LOD methods, based on locally higher-order methods. We discuss the new theoretical results of the stability and consistency of the ADI methods. The main idea is to apply a higherorder time discretization and combine it with the ADI methods. We also discuss the discretization and splitting methods for first-order and second-order evolution equations. The stability analysis is given for the ADI method for first-order time derivatives and for the LOD (locally one-dimensional) methods for second-order time derivatives. The higher-order methods are unconditionally stable. Some numerical experiments verify our results.
Stability change of Fourth-Order Resonance with application to Multi-Turn Extraction Schemes
Giovannozzi, M; Turchetti, G
2008-01-01
Recently, a novel multi-turn extraction scheme was proposed, based on particle trapping inside stable resonances. Numerical simulations and experimental tests conirmed the feasibility of such a scheme for low order resonances. While the 3rd order resonance is generically unstable and those higher than 4th order are generically stable, the 4th order resonance can be either stable or unstable depending on the details of the system under consideration. By means of the normal form approach a general formula to control the stability of the 4th order resonance is derived. Numerical simulations confirm the analytical results and show that by crossing the unstable 4th order resonance the region around the centre of phase space is depleted and particles are trapped only in the four stable islands. This indicates that a four-turn extraction could be envisaged based on this technique.
Kulshreshtha, Kshitij; Nataraj, Neela
2005-08-01
The paper deals with a parallel implementation of a mixed finite element method of approximation of eigenvalues and eigenvectors of fourth order eigenvalue problems with variable/constant coefficients. The implementation has been done in Silicon Graphics Origin 3800, a four processor Intel Xeon Symmetric Multiprocessor and a beowulf cluster of four Intel Pentium III PCs. The generalised eigenvalue problem obtained after discretization using the mixed finite element method is solved using the package LANSO. The numerical results obtained are compared with existing results (if available). The time, speedup comparisons in different environments for some examples of practical and research interest and importance are also given.
Wright, G. B.; Barnett, G. A.; Yuen, D. A.
2009-12-01
We present an efficient method based on fourth order compact finite-differences for simulating three dimensional mantle convection (i.e. Rayleigh-Bénard convection in the infinite Prandtl number limit) with constant viscosity in a rectangular box. In the high Rayleigh number regime, this thermal convection model has recently been shown to exhibit many of the features of turbulent flow that are typically identified with high Reynolds number flow [1]. High order compact finite schemes are known to be particularly good for simulating turbulent flows because of their spectral like resolution [2], which ameliorates dispersion and anisotropy errors. They have also been shown to be much less susceptible than second order schemes to spurious oscillations for transient convection diffusion equations at large Péclet number (as occurs for the temperature equation in the mantle convection model at high Rayleigh number). Finally, high order schemes have been shown to be more efficient than low order methods in terms of degrees of freedom required to attain a specified error level, which is important for reducing memory requirements so simulations can be performed on emerging low-cost high performance computational platforms like graphics processing units (GPUs). We demonstrate the capabilities of our compact fourth order scheme at accurately capturing such phenomena as transient periods of double layered convection[3] (see Figure 1) and flow reversals using far fewer degrees of freedom than required for traditional second order methods. Finally, we discuss the computational cost of the scheme and its efficient implementation on GPUs. References: [1] M. Breuer and U. Hansen, Turbulent convection in the zero Reynolds number limit, EPL, 86, 24004, 2009. [2] S. K. Lele, Compact finite difference schemes with spectral-like resolution, J. Comput. Phys., 103, 16, 1992. [3] A. P. Boss and I. S. Sacks, Time-dependent models of single- and double-layer mantle convection, Nature, 308
A perturbative method to solve fourth-order gravity field equations
Campanelli, M; Audretsch, J
1994-01-01
We develop a method for solving the field equations of a quadratic gravitational theory coupled to matter. The quadratic terms are written as a function of the matter stress tensor and its derivatives in such a way to have, order by order, a set of Einstein field equations with an effective $T_{\\mu\
A Perturbative Method to solve fourth-order Gravity Field Equations
Campanelli, M.; Lousto, C. O.; Audretsch, J.
1994-01-01
We develop a method for solving the field equations of a quadratic gravitational theory coupled to matter. The quadratic terms are written as a function of the matter stress tensor and its derivatives in such a way to have, order by order, a set of Einstein field equations with an effective $T_{\\mu\
Sen, Shuvam
2012-01-01
In this paper, a new family of implicit compact finite difference schemes for computation of unsteady convection-diffusion equation with variable convection coefficient is proposed. The schemes are fourth order accurate in space and second or lower order accurate in time depending on the choice of weighted time average parameter. The proposed schemes, where transport variable and its first derivatives are carried as the unknowns, combine virtues of compact discretization and Pad\\'{e} scheme for spatial derivative. These schemes which are based on five point stencil with constant coefficients, named as \\emph{(5,5) Constant Coefficient 4th Order Compact} [(5,5)CC-4OC], give rise to a diagonally dominant system of equations and shows higher accuracy and better phase and amplitude error characteristics than some of the standard methods. These schemes are capable of using a grid aspect ratio other than unity and are unconditionally stable. They efficiently capture both transient and steady solutions of linear and ...
Vilanova, Anna; Burgeth, Bernhard; Visualization and Processing of Tensors and Higher Order Descriptors for Multi-Valued Data
2014-01-01
Arising from the fourth Dagstuhl conference entitled Visualization and Processing of Tensors and Higher Order Descriptors for Multi-Valued Data (2011), this book offers a broad and vivid view of current work in this emerging field. Topics covered range from applications of the analysis of tensor fields to research on their mathematical and analytical properties. Part I, Tensor Data Visualization, surveys techniques for visualization of tensors and tensor fields in engineering, discusses the current state of the art and challenges, and examines tensor invariants and glyph design, including an overview of common glyphs. The second Part, Representation and Processing of Higher-order Descriptors, describes a matrix representation of local phase, outlines mathematical morphological operations techniques, extended for use in vector images, and generalizes erosion to the space of diffusion weighted MRI. Part III, Higher Order Tensors and Riemannian-Finsler Geometry, offers powerful mathematical language to model and...
Regularized Positive-Definite Fourth Order Tensor Field Estimation from DW-MRI★
2008-01-01
In Diffusion Weighted Magnetic Resonance Image (DW-MRI) processing, a 2nd order tensor has been commonly used to approximate the diffusivity function at each lattice point of the DW-MRI data. From this tensor approximation, one can compute useful scalar quantities (e.g. anisotropy, mean diffusivity) which have been clinically used for monitoring encephalopathy, sclerosis, ischemia and other brain disorders. It is now well known that this 2nd-order tensor approximation fails to capture complex...
Steijl, R.; Hoeijmakers, H. W. M.
2004-09-01
A fourth-order accurate solution method for the three-dimensional Helmholtz equations is described that is based on a compact finite-difference stencil for the Laplace operator. Similar discretization methods for the Poisson equation have been presented by various researchers for Dirichlet boundary conditions. Here, the complicated issue of imposing Neumann boundary conditions is described in detail. The method is then applied to model Helmholtz problems to verify the accuracy of the discretization method. The implementation of the solution method is also described. The Helmholtz solver is used as the basis for a fourth-order accurate solver for the incompressible Navier-Stokes equations. Numerical results obtained with this Navier-Stokes solver for the temporal evolution of a three-dimensional instability in a counter-rotating vortex pair are discussed. The time-accurate Navier-Stokes simulations show the resolving properties of the developed discretization method and the correct prediction of the initial growth rate of the three-dimensional instability in the vortex pair.
Regularized Positive-Definite Fourth Order Tensor Field Estimation from DW-MRI★
Barmpoutis, Angelos; Vemuri, Baba C.; Howland, Dena; Forder, John R.
2009-01-01
In Diffusion Weighted Magnetic Resonance Image (DW-MRI) processing, a 2nd order tensor has been commonly used to approximate the diffusivity function at each lattice point of the DW-MRI data. From this tensor approximation, one can compute useful scalar quantities (e.g. anisotropy, mean diffusivity) which have been clinically used for monitoring encephalopathy, sclerosis, ischemia and other brain disorders. It is now well known that this 2nd-order tensor approximation fails to capture complex local tissue structures, e.g. crossing fibers, and as a result, the scalar quantities derived from these tensors are grossly inaccurate at such locations. In this paper we employ a 4th order symmetric positive-definite (SPD) tensor approximation to represent the diffusivity function and present a novel technique to estimate these tensors from the DW-MRI data guaranteeing the SPD property. Several articles have been reported in literature on higher order tensor approximations of the diffusivity function but none of them guarantee the positivity of the estimates, which is a fundamental constraint since negative values of the diffusivity are not meaningful. In this paper we represent the 4th-order tensors as ternary quartics and then apply Hilbert’s theorem on ternary quartics along with the Iwasawa parametrization to guarantee an SPD 4th-order tensor approximation from the DW-MRI data. The performance of this model is depicted on synthetic data as well as real DW-MRIs from a set of excised control and injured rat spinal cords, showing accurate estimation of scalar quantities such as generalized anisotropy and trace as well as fiber orientations. PMID:19063978
Regularized positive-definite fourth order tensor field estimation from DW-MRI.
Barmpoutis, Angelos; Hwang, Min Sig; Howland, Dena; Forder, John R; Vemuri, Baba C
2009-03-01
In Diffusion Weighted Magnetic Resonance Image (DW-MRI) processing, a 2nd order tensor has been commonly used to approximate the diffusivity function at each lattice point of the DW-MRI data. From this tensor approximation, one can compute useful scalar quantities (e.g. anisotropy, mean diffusivity) which have been clinically used for monitoring encephalopathy, sclerosis, ischemia and other brain disorders. It is now well known that this 2nd-order tensor approximation fails to capture complex local tissue structures, e.g. crossing fibers, and as a result, the scalar quantities derived from these tensors are grossly inaccurate at such locations. In this paper we employ a 4th order symmetric positive-definite (SPD) tensor approximation to represent the diffusivity function and present a novel technique to estimate these tensors from the DW-MRI data guaranteeing the SPD property. Several articles have been reported in literature on higher order tensor approximations of the diffusivity function but none of them guarantee the positivity of the estimates, which is a fundamental constraint since negative values of the diffusivity are not meaningful. In this paper we represent the 4th-order tensors as ternary quartics and then apply Hilbert's theorem on ternary quartics along with the Iwasawa parametrization to guarantee an SPD 4th-order tensor approximation from the DW-MRI data. The performance of this model is depicted on synthetic data as well as real DW-MRIs from a set of excised control and injured rat spinal cords, showing accurate estimation of scalar quantities such as generalized anisotropy and trace as well as fiber orientations.
Numerical analysis of fourth-order boundary value problems in fluid mechanics and mathematics
DEFF Research Database (Denmark)
Hosseinzadeh, Elham; Barari, Amin; Fouladi, Fama
2010-01-01
In this paper He's variational iteration method is used to solve some examples of linear and non-linear forth-order boundary value problems. The first problem compared with homotopy analysis method solution and the other ones with the exact solution. The results show the high accuracy and speed...
Recovery of singularities in a fourth-order operator on the line from limited data
Tyni, Teemu; Harju, Markus; Serov, Valery
2016-07-01
We consider a differential operator of order four with three coefficients which may be complex valued. We prove that the Born approximation can be used efficiently to recover essential information about a combination of the coefficients from the knowledge of the reflection coefficient. Numerical examples illustrate the feasibility of this method.
Explicit fourth-order stiffness representation in non-linear dynamics
DEFF Research Database (Denmark)
Krenk, Steen
2013-01-01
global form of the effective internal force is presented, in which it is represented by its algebraic mean value plus a higher order term in the form of the product of the increment of the tangent stiffness matrix at the interval end-points and the corresponding displacement increment. This explicit...
Error Patterns in Ordering Fractions among At-Risk Fourth-Grade Students
Malone, Amelia Schneider; Fuchs, Lynn S.
2015-01-01
The 3 purposes of this study were to: (a) describe fraction ordering errors among at-risk 4th-grade students; (b) assess the effect of part-whole understanding and accuracy of fraction magnitude estimation on the probability of committing errors; and (c) examine the effect of students' ability to explain comparing problems on the probability of…
Mohmand, Muhammad Ismail; Mamat, Mustafa Bin; Shah, Qayyum
2017-07-01
This article deals with the time dependent analysis of thermally conducting and Magneto-hydrodynamic (MHD) liquid film flow of a fourth order fluid past a vertical and vibratory plate. In this article have been developed for higher order complex nature fluids. The governing-equations have been modeled in the terms of nonlinear partial differential equations with the help of physical boundary circumstances. Two different analytical approaches i.e. Adomian decomposition method (ADM) and the optimal homotopy asymptotic method (OHAM), have been used for discoveryof the series clarification of the problems. Solutions obtained via two diversemethods have been compared using the graphs, tables and found an excellent contract. Variants of the embedded flow parameters in the solution have been analysed through the graphical diagrams.
Suzuki, Kimichi; Shiga, Motoyuki; Tachikawa, Masanori
2008-10-01
Path integral molecular dynamics simulation based on the fourth order Trotter expansion has been performed to elucidate the geometrical isotope effect of water dimer anions, H3O2-, D3O2-, and T3O2-, at different temperatures from 50 to 600 K. At low temperatures below 200 K the hydrogen-bonded hydrogen nucleus is near the center of two oxygen atoms with mostly O⋯X⋯O geometry (where X =H, D, or T), while at high temperatures above 400 K, hydrogen becomes more delocalized, showing the coexistence between O⋯X-O and O-X⋯O. The OO distance tends to be shorter as the isotopomer is heavier at low temperatures, while this ordering becomes opposite at high temperatures. It is concluded that the coupling between the OO stretching mode and proton transfer modes is a key to understand such a temperature dependence of a hydrogen-bonded structure.
Matthews, Devin A.; Gong, Justin Z.; Stanton, John F.
2014-06-01
The derivation of analytic expressions for vibrational and rovibrational constants, for example the anharmonicity constants χij and the vibration-rotation interaction constants α^B_r, from second-order vibrational perturbation theory (VPT2) can be accomplished with pen and paper and some practice. However, the corresponding quantities from fourth-order perturbation theory (VPT4) are considerably more complex, with the only known derivations by hand extensively using many layers of complicated intermediates and for rotational quantities requiring specialization to orthorhombic cases or the form of Watson's reduced Hamiltonian. We present an automatic computer program for generating these expressions with full generality based on the adaptation of an existing numerical program based on the sum-over-states representation of the energy to a computer algebra context. The measures taken to produce well-simplified and factored expressions in an efficient manner are discussed, as well as the framework for automatically checking the correctness of the generated equations.
Fourth-order split monopole perturbation solutions to the Blandford-Znajek mechanism
Pan, Zhen
2015-01-01
The Blandford-Znajek (BZ) mechanism describes a physical process for the energy extraction from a spinning black hole (BH), which is believed to power a great variety of astrophysical sources, such as active galactic nuclei (AGNs) and Gamma ray bursts (GRBs). The only known analytic solution to the BZ mechanism is a split monopole perturbation solution up to $O(a^2)$, where $a$ is the spin parameter of a Kerr black hole. In this paper, we extend the monopole solution to higher order $\\sim O(a^4)$. We carefully investigate the structure of the BH magnetosphere, including the angular velocity of magnetic field lines $\\Omega$, the toroidal magnetic field $B^\\phi$ as well as the poloidal electric current $I$. In addition, the relevant energy extraction rate $\\dot E$ and the stability of this high-order monopole perturbation solution are also examined.
A 3D Unstructured Mesh Euler Solver Based on the Fourth-Order CESE Method
2013-06-01
conservation in space and time without using a one-dimensional Riemann solver, (ii) genuinely multi-dimensional treatment without dimensional splitting (iii...of the original second-order CESE method, including: (i) flux conservation in space and time without using a one-dimensional Riemann solver, (ii...treated in a unified manner. The geometry for a three-dimensional CESE method is more difficult to visualize than the one- and two-dimensional methods
Stationary solutions of driven fourth- and sixth-order Cahn-Hilliard type equations
Korzec, M D; Münch, A; Wagner, B
2007-01-01
New types of stationary solutions of a one-dimensional driven sixth-order Cahn-Hilliard type equation that arises as a model for epitaxially growing nano-structures such as quantum dots, are derived by an extension of the method of matched asymptotic expansions that retains exponentially small terms. This method yields analytical expressions for far-field behavior as well as the widths of the humps of these spatially non-monotone solutions in the limit of small driving force strength which is the deposition rate in case of epitaxial growth. These solutions extend the family of the monotone kink and antikink solutions. The hump spacing is related to solutions of the Lambert $W$ function. Using phase space analysis for the corresponding fifth-order dynamical system, we use a numerical technique that enables the efficient and accurate tracking of the solution branches, where the asymptotic solutions are used as initial input. Additionally, our approach is first demonstrated for the related but simpler driven fou...
Birse, Michael C
2012-01-01
We calculate the amplitude T_1 for forward doubly-virtual Compton scattering in heavy-baryon chiral perturbation theory, to fourth order in the chiral expansion and with the leading contribution of the gammaNDelta form factor. This provides a model-independent expression for the amplitude in the low-momentum region, which is the dominant one for its contribution to the Lamb shift. It allows us to significantly reduce the theoretical uncertainty in the proton polarisability contributions to the Lamb shift in muonic hydrogen. We also stress the importance of consistency between the definitions of the Born and structure parts of the amplitude. Our result leaves no room for any effect large enough to explain the discrepancy between proton charge radii as determined from muonic and normal hydrogen.
Energy Technology Data Exchange (ETDEWEB)
Birse, M.C.; McGovern, J.A. [University of Manchester, Theoretical Physics Division, School of Physics and Astronomy, Manchester (United Kingdom)
2012-09-15
We calculate the amplitude T{sub 1} for forward doubly virtual Compton scattering in heavy-baryon chiral perturbation theory, to fourth order in the chiral expansion and with the leading contribution of the {gamma}N{Delta} form factor. This provides a model-independent expression for the amplitude in the low-momentum region, which is the dominant one for its contribution to the Lamb shift. It allows us to significantly reduce the theoretical uncertainty in the proton polarisability contributions to the Lamb shift in muonic hydrogen. We also stress the importance of consistency between the definitions of the Born and structure parts of the amplitude. Our result leaves no room for any effect large enough to explain the discrepancy between proton charge radii as determined from muonic and normal hydrogen. (orig.)
Multiple positive solutions for fourth-order three-point p-Laplacian boundary-value problems
Directory of Open Access Journals (Sweden)
Hanying Feng
2007-02-01
Full Text Available In this paper, we study the three-point boundary-value problem for a fourth-order one-dimensional $p$-Laplacian differential equation $$ ig(phi_p(u''(tig''+ a(tfig(u(tig=0, quad tin (0,1, $$ subject to the nonlinear boundary conditions: $$displaylines{ u(0=xi u(1,quad u'(1=eta u'(0,cr (phi _{p}(u''(0' =alpha _{1}(phi _{p}(u''(delta', quad u''(1=sqrt[p-1]{eta _{1}}u''(delta, }$$ where $phi_{p}(s=|s|^{p-2}s$, $p>1$. Using the five functional fixed point theorem due to Avery, we obtain sufficient conditions for the existence of at least three positive solutions.
Souri, Effat; Mosafer, Amir; Tehrani, Maliheh Barazandeh
2016-01-01
Combination dosage forms of naproxen sodium and pseudoephedrine hydrochloride are used for symptomatic treatment of cold and sinus disorders. In this study, fourth-order derivative spectrophotometric method was used for simultaneous determination of naproxen sodium and pseudoephedrine hydrochloride. The method was linear over the range of 2-28 μg/ml for pseudoephedrine hydrochloride and 4-200 μg/ml for naproxen sodium. The within-day and between-day coefficient of variation values were less than 5.8% and 2.5% for pseudoephedrine hydrochloride and naproxen sodium, respectively. The application of the proposed method for simultaneous determination of naproxen and pseudoephedrine in dosage forms was demonstrated without any special pretreatment.
Ying, L H
2012-01-01
Nonlinear instability and refraction by ocean currents are both important mechanisms that go beyond the Rayleigh approximation and may be responsible for the formation of freak waves. In this paper, we quantitatively study nonlinear effects on the evolution of surface gravity waves on the ocean, to explore systematically the effects of various input parameters on the probability of freak wave formation. The fourth-order current-modified nonlinear Schr\\"odinger equation (CNLS4) is employed to describe the wave evolution. By solving CNLS4 numerically, we are able to obtain quantitative predictions for the wave height distribution as a function of key environmental conditions such as average steepness, angular spread, and frequency spread of the local sea state. Additionally, we explore the spatial dependence of the wave height distribution, associated with the buildup of nonlinear development.
Directory of Open Access Journals (Sweden)
Effat Souri
2016-01-01
Full Text Available Combination dosage forms of naproxen sodium and pseudoephedrine hydrochloride are used for symptomatic treatment of cold and sinus disorders. In this study, fourth-order derivative spectrophotometric method was used for simultaneous determination of naproxen sodium and pseudoephedrine hydrochloride. The method was linear over the range of 2-28 μg/ml for pseudoephedrine hydrochloride and 4-200 μg/ml for naproxen sodium. The within-day and between-day coefficient of variation values were less than 5.8% and 2.5% for pseudoephedrine hydrochloride and naproxen sodium, respectively. The application of the proposed method for simultaneous determination of naproxen and pseudoephedrine in dosage forms was demonstrated without any special pretreatment.
On Higgs-exchange DIS, physical evolution kernels and fourth-order splitting functions at large x
Energy Technology Data Exchange (ETDEWEB)
Soar, G.; Vogt, A. [Liverpool Univ. (United Kingdom). Dept. of Mathematical Sciences; Moch, S. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Vermaseren, J.A.M. [NIKHEF, Amsterdam (Netherlands)
2009-12-15
We present the coefficient functions for deep-inelastic scattering (DIS) via the exchange of a scalar {phi} directly coupling only to gluons, such as the Higgs boson in the limit of a very heavy top quark and n{sub f} effectively massless light flavours, to the third order in perturbative QCD. The two-loop results are employed to construct the next-to-next-to-leading order physical evolution kernels for the system (F{sub 2},F{sub {phi}}) of flavour-singlet structure functions. The practical relevance of these kernels as an alternative to MS factorization is bedevilled by artificial double logarithms at small values of the scaling variable x, where the large top-mass limit ceases to be appropriate. However, they show an only single-logarithmic enhancement at large x. Conjecturing that this feature persists to the next order also in the present singlet case, the three-loop coefficient functions facilitate exact predictions (backed up by their particular colour structure) of the double-logarithmic contributions to the fourth-order singlet splitting functions, i.e., of the terms (1-x){sup a} ln{sup k}(1-x) with k=4,5,6 and k=3,4,5, respectively, for the off-diagonal and diagonal quantities to all powers a in (1-x). (orig.)
Levi, Michele
2014-01-01
The next-to-next-to-leading order spin1-spin2 potential for an inspiralling binary, that is essential for accuracy to fourth post-Newtonian order, if both components in the binary are spinning rapidly, has been recently derived independently via the ADM Hamiltonian and the Effective Field Theory approaches, using different gauges and variables. Here we show the complete physical equivalence of the two results, thereby we first prove the equivalence of the ADM Hamiltonian and the Effective Field Theory approaches at next-to-next-to-leading order with the inclusion of spins. The main difficulty in the spinning sectors, which also prescribes the manner in which the comparison of the two results is tackled here, is the existence of redundant unphysical spin degrees of freedom, associated with the spin gauge choice of a point within the extended spinning object for its representative worldline. After gauge fixing and eliminating the unphysical degrees of freedom of the spin and its conjugate at the level of the ac...
Bernard, Laura; Bohé, Alejandro; Faye, Guillaume; Marsat, Sylvain
2016-01-01
In this paper, we complete our preceding work on the Fokker Lagrangian describing the dynamics of compact binary systems at the fourth post-Newtonian (4PN) order in harmonic coordinates. We clarify the impact of the non-local character of the Fokker Lagrangian or the associated Hamiltonian on both the conserved energy and the relativistic periastron precession for circular orbits. We show that the non-locality of the action, due to the presence of the tail effect at the 4PN order, gives rise to an extra contribution to the conserved integral of energy with respect to the Hamiltonian computed on shell, which was not taken into account in our previous work. We also provide a direct derivation of the periastron advance by taking carefully into account this non-locality. We then argue that the infra-red (IR) divergences in the calculation of the gravitational part of the action are problematic, which motivates us to introduce a second ambiguity parameter, in addition to the one already assumed previously. After f...
Wang, Ying; Zhou, Hui; Yuan, Sanyi; Ye, Yameng
2017-01-01
The fourth order accuracy finite difference scheme is known advantageous in reducing memory and improving efficiency. Summation-by-parts finite difference operator is a natural way for wavefield simulation in complicated domains containing surface topography and irregular interfaces. The application of summation-by-parts method guarantees the stability of numerical approximation for heterogeneous media on curvilinear grids. This paper extends the second order summation-by-parts finite difference method to the fourth order case for the discretization of acoustic wave equation and perfect matched layer in boundary-conforming grids. In particular, the implementation of the fourth order method for wavefield simulation and reverse time migration in complicated domains can significantly improve the efficiency and decrease the storage. The elliptic method is applied for boundary-conforming grid generation in complicated domains. Under such grids, the two-dimensional acoustic wave equation in second order displacement formulation is compactly reformulated for forward modeling and reverse time migration, and the symmetric and compact form of perfectly matched layers expressed in a curvilinear coordinate system are applied to suppress artificial reflections. The discretizations of the acoustic wave equation and perfectly matched layer formula are fourth and second order accuracy in space and time respectively, where the spatial discretization satisfies the principle of summation-by-parts and is stable. Numerical experiments are presented to compare the accuracy of the second with fourth order summation-by-parts finite difference methods and to evaluate the efficiency of reverse time migration by using these two methods. As well, comparisons are performed between the fourth order accuracy summation-by-parts finite difference method and central finite difference method to illustrate the stability superiority of summation-by-parts operators.
A new DOA estimation algorithm based on fourth-order cumulant%一种新的基于四阶累积量的DOA估计算法
Institute of Scientific and Technical Information of China (English)
朱敏; 何培宇
2011-01-01
A new algorithm based on fourth-order cumulant matrix is presented for uniform linear array.There are massive redundant data in the fourth-order cumulant matrix for MUSIC-like algorithm.So a new method of constructing the fourth-order cumulant matrix is created in the proposed algorithm.In the case of keeping the array extension ability, the fourth-order cumulant matrix constructed using the new method eliminates massive redundant data of the fourth-order cumulant matrix in MUSIC-like algorithm and reduces the order of the matrix.So compared with MUSIC-like algorithm, the proposed algorithm not only has the same performance of DOA estimation, but also brings the benefits of significant reduction of computational complexity.Computer simulations are carried out to illustrate the validity of the new method.%提出了一种新的用于均匀线阵的四阶累积量DOA估计算法.针对传统MUSIC-like算法中四阶累积量矩阵存在大量冗余信息的情况,本文算法提出了一种新的四阶累积量矩阵构造方法.用该方法构造的四阶累积量矩阵在保证阵列扩展性能的同时,去掉了MUSIC-like算法中四阶累积量矩阵的冗余信息,降低了矩阵的阶数.与MUSIC-like算法相比,本文算法的运算复杂度显著降低,但仍保持了同等的估计性能.实验仿真表明了提出方法的有效性.
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
By making use of the generalized sine-Gordon equation expansion method, we find cnoidal periodic wave solutions and fundamental bright and dark optical solitarywave solutions for the fourth-order dispersive and the quintic nonlinear Schrodinger equation with self-steepening, and self-frequency shift. Moreover, we discuss the formation conditions of the bright and dark solitary waves.
Canivez, Gary L.; Watkins, Marley W.
2010-01-01
The factor structure of the Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV; Wechsler, 2008a) with the adolescent participants (ages 16-19 years; N = 400) in the standardization sample was assessed using exploratory factor analysis, multiple factor extraction criteria, and higher-order exploratory factor analyses. Results from…
Canivez, Gary L.; Watkins, Marley W.
2010-01-01
The present study examined the factor structure of the Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV; D. Wechsler, 2008a) standardization sample using exploratory factor analysis, multiple factor extraction criteria, and higher order exploratory factor analysis (J. Schmid & J. M. Leiman, 1957) not included in the WAIS-IV Technical…
Canivez, Gary L.; Watkins, Marley W.
2010-01-01
The present study examined the factor structure of the Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV; D. Wechsler, 2008a) standardization sample using exploratory factor analysis, multiple factor extraction criteria, and higher order exploratory factor analysis (J. Schmid & J. M. Leiman, 1957) not included in the WAIS-IV Technical…
Canivez, Gary L.; Watkins, Marley W.
2010-01-01
The factor structure of the Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV; Wechsler, 2008a) with the adolescent participants (ages 16-19 years; N = 400) in the standardization sample was assessed using exploratory factor analysis, multiple factor extraction criteria, and higher-order exploratory factor analyses. Results from…
Keith, Timothy Z.; Fine, Jodene Goldenring; Taub, Gordon E.; Reynolds, Matthew R.; Kranzler, John H.
2006-01-01
The recently published fourth edition of the Wechsler Intelligence Scale for Children (WISC-IV) represents a considerable departure from previous versions of the scale. The structure of the instrument has changed, and some subtests have been added and others deleted. The technical manual for the WISC-IV provided evidence supporting this new…
Bayramoglu, Husnu; Komurcugil, Hasan
2014-07-01
A time-varying sliding-coefficient-based decoupled terminal sliding mode control strategy is presented for a class of fourth-order systems. First, the fourth-order system is decoupled into two second-order subsystems. The sliding surface of each subsystem was designed by utilizing time-varying coefficients. Then, the control target of one subsystem to another subsystem was embedded. Thereafter, a terminal sliding mode control method was utilized to make both subsystems converge to their equilibrium points in finite time. The simulation results on the inverted pendulum system demonstrate that the proposed method exhibits a considerable improvement in terms of a faster dynamic response and lower IAE and ITAE values as compared with the existing decoupled control methods.
Mohd Fauzi, Norizyan Izzati; Sulaiman, Jumat
2013-04-01
The aim of this paper is to describe the application of Quarter-Sweep Gauss-Seidel (QSGS) iterative method using quadratic spline scheme for solving fourth order two-point linear boundary value problems. In the line to derive approximation equations, firstly the fourth order problems need to be reduced onto a system of second-order two-point boundary value problems. Then two linear systems have been constructed via discretization process by using the corresponding quarter-sweep quadratic spline approximation equations. The generated linear systems have been solved using the proposed QSGS iterative method to show the superiority over Full-Sweep Gauss-Seidel (FSGS) and Half-Sweep Gauss-Seidel (HSGS) methods. Computational results are provided to illustrate that the effectiveness of the proposed QSGS method is more superior in terms of computational time and number of iterations as compared to other tested methods.
Pan, Liang; Xu, Kun; Li, Qibing; Li, Jiequan
2016-12-01
For computational fluid dynamics (CFD), the generalized Riemann problem (GRP) solver and the second-order gas-kinetic scheme (GKS) provide a time-accurate flux function starting from a discontinuous piecewise linear flow distributions around a cell interface. With the adoption of time derivative of the flux function, a two-stage Lax-Wendroff-type (L-W for short) time stepping method has been recently proposed in the design of a fourth-order time accurate method for inviscid flow [21]. In this paper, based on the same time-stepping method and the second-order GKS flux function [42], a fourth-order gas-kinetic scheme is constructed for the Euler and Navier-Stokes (NS) equations. In comparison with the formal one-stage time-stepping third-order gas-kinetic solver [24], the current fourth-order method not only reduces the complexity of the flux function, but also improves the accuracy of the scheme. In terms of the computational cost, a two-dimensional third-order GKS flux function takes about six times of the computational time of a second-order GKS flux function. However, a fifth-order WENO reconstruction may take more than ten times of the computational cost of a second-order GKS flux function. Therefore, it is fully legitimate to develop a two-stage fourth order time accurate method (two reconstruction) instead of standard four stage fourth-order Runge-Kutta method (four reconstruction). Most importantly, the robustness of the fourth-order GKS is as good as the second-order one. In the current computational fluid dynamics (CFD) research, it is still a difficult problem to extend the higher-order Euler solver to the NS one due to the change of governing equations from hyperbolic to parabolic type and the initial interface discontinuity. This problem remains distinctively for the hypersonic viscous and heat conducting flow. The GKS is based on the kinetic equation with the hyperbolic transport and the relaxation source term. The time-dependent GKS flux function
Analysis of Nonlocal Fourth-Order Coincindence with Thermal Light%热光源的四阶关联成像的研究
Institute of Scientific and Technical Information of China (English)
吴闯; 刘英斌; 郑伟; 高岩
2011-01-01
Recently coherent of light field is attracting more attention by domestic and foreign scholars.First-order coherence has been mainly investigated in traditional optics.Further, the successes in HBT experiment break the limitations of traditional optics which develop the physical meanings of the coherence.In this paper, we propose a concept and experimental sheme of fourth-order correction based on the traditional optics and coherent theory.Through the analysis on fourth-order correction function carefully, we express the fourth-order correction function with its first-order form and calculate hy considering the light intensity from the four detectors.We show the background noise and the part of imaging by analysizing the results in our calculation.We obtain that it is realizable in fourth-order correction imaging theoretically.%近年来,光场的相干性理论受到国内外学者的广泛关注.传统光学研究的主要是光场的一阶相干性,HBT实验的成功打破了传统光学的局限性,开拓了相干性的物理含义.在传统光学和相干性理论研究的基础上,提出了四阶关联的概念和实验方案.通过将四阶关联函数用它的一阶形式来表示,并考虑到四个探测器处的光场强度,对计算结果中的每一项进行分析,区分出其中的背景噪声和对成像有贡献的部分,研究表明四阶关联成像在理论上是可以实现的.
Yan, Yangqian; Blume, D
2016-06-10
The unitary equal-mass Fermi gas with zero-range interactions constitutes a paradigmatic model system that is relevant to atomic, condensed matter, nuclear, particle, and astrophysics. This work determines the fourth-order virial coefficient b_{4} of such a strongly interacting Fermi gas using a customized ab initio path-integral Monte Carlo (PIMC) algorithm. In contrast to earlier theoretical results, which disagreed on the sign and magnitude of b_{4}, our b_{4} agrees within error bars with the experimentally determined value, thereby resolving an ongoing literature debate. Utilizing a trap regulator, our PIMC approach determines the fourth-order virial coefficient by directly sampling the partition function. An on-the-fly antisymmetrization avoids the Thomas collapse and, combined with the use of the exact two-body zero-range propagator, establishes an efficient general means to treat small Fermi systems with zero-range interactions.
Some Properties and Applications of Fourth-Order Fibonacci Sequence%四阶斐波那契数列性质及应用
Institute of Scientific and Technical Information of China (English)
庞荣波
2015-01-01
Based on the Fibonacci sequence, the concept of the fourth-order Fibonacci sequence is given. In this paper , we prove some properties of the fourth-order Fibonacci sequence and point out its applications in integer par-titions. Moreover, we give a conjecture relating to this sequence.%在研究斐波那契数列的基础上，提出了四阶斐波那契数列的概念。探讨了四阶斐波那契数列的一些性质，并给出了1个猜想，指出了四阶斐波那契数列在整数分拆中的应用。
Sharp, Robert
2008-10-14
Mn(II) is a spin-5/2 paramagnetic ion that mediates a characteristically large NMR paramagnetic relaxation enhancement (NMR-PRE) of nuclear spins in solution. In the range of high magnetic field strengths (above about 0.3 T), where the electronic Zeeman interaction provides the largest term of the electron spin Hamiltonian, NMR relaxation mechanism is well understood. In the lower field range, the physical picture is more complex because of the presence in the spin Hamiltonian of zero field splitting (ZFS) terms that are comparable to or greater than the Zeeman term. This work describes a systematic study of the relaxation mechanism in the low field range, particularly aspects involving the dependence of NMR-PRE on the orthorhombic (E) and fourth-order (a(q)(4), q=0,2,4) ZFS tensor components. It is shown that the fourfold (a(4)(4)) and twofold (a(2)(4)) fourth-order components exert large orientation-dependent influences on the NMR-PRE. Thus, fourth-order terms with magnitudes equal to only a few percent of the quadratic ZFS terms (D,E) produce large changes in the shape of the magnetic field profile of the PRE. Effects arising from the orthorhombic quadratic ZFS term (E) are much smaller than those of the fourth-order terms and can in most cases be neglected. However, effects due to a(4)(4) and a(2)(4) need to be included in simulations of low field data.
四阶奇异边值问题的正解%Positive Solutions of Fourth Order Singular Boundary Value Problems
Institute of Scientific and Technical Information of China (English)
孙彦; 徐本龙
2004-01-01
Using fixedpoint index theory, we study the existence of positive solutions of the fourth order differential equation d4u/dt4 - g(t)F(t, u(t)) = 0 with some general boundary conditions, where g(t) is allowed to be singular at t = 0 and/or 1. Our results significantly extend and improve many known results even for non-singular cases. An example is given to show how to apply our theorems.
一类四阶边值问题的正解%POSITIVE SOLUTIONS OF A FOURTH ORDER BOUNDARY VALUE PROBLEM
Institute of Scientific and Technical Information of China (English)
任立顺
2003-01-01
The existence of positive solutions of the nonlinear fourth order problem u(4)(x) = λa(x)f(u(x)),u(0) = u'(0) = u'(1) = u"'(1) = 0 is studied, where a:[0,1]→R may change sign, f(0)＞0,λ＞0 is sufficiently smallOurapproach is based on the Leray-Schauder fixed point theorem.
Canivez, Gary L; Watkins, Marley W
2010-12-01
The present study examined the factor structure of the Wechsler Adult Intelligence Scale--Fourth Edition (WAIS-IV; D. Wechsler, 2008a) standardization sample using exploratory factor analysis, multiple factor extraction criteria, and higher order exploratory factor analysis (J. Schmid & J. M. Leiman, 1957) not included in the WAIS-IV Technical and Interpretation Manual (D. Wechsler, 2008b). Results indicated that the WAIS-IV subtests were properly associated with the theoretically proposed first-order factors, but all but one factor-extraction criterion recommended extraction of one or two factors. Hierarchical exploratory analyses with the Schmid and Leiman procedure found that the second-order g factor accounted for large portions of total and common variance, whereas the four first-order factors accounted for small portions of total and common variance. It was concluded that the WAIS-IV provides strong measurement of general intelligence, and clinical interpretation should be primarily at that level.
Institute of Scientific and Technical Information of China (English)
同小军; 同登科; 陈绵云
2001-01-01
For the formal presentation about the definite problems of ultra-hyperbolic equations, the famous Asgeirsson mean value theorem has answered that Cauchy problems are ill-posed to ultra-hyperbolic partial differential equations of the second-order. So it is important to develop Asgeirsson mean value theorem. The mean value of solution for the higher order equation has been discussed primarily and has no exact result at present. The mean value theorem for the higher order equation can be deduced and satisfied generalized biaxial symmetry potential equation by using the result of Asgeirsson mean value theorem and the properties of derivation and integration. Moreover, the mean value formula can be obtained by using the regular solutions of potential equation and the special properties of Jacobi polynomials. Its converse theorem is also proved. The obtained results make it possible to discuss on continuation of the solutions and well posed problem.
The a(3) Scheme--A Fourth-Order Space-Time Flux-Conserving and Neutrally Stable CESE Solver
Chang, Sin-Chung
2008-01-01
The CESE development is driven by a belief that a solver should (i) enforce conservation laws in both space and time, and (ii) be built from a non-dissipative (i.e., neutrally stable) core scheme so that the numerical dissipation can be controlled effectively. To initiate a systematic CESE development of high order schemes, in this paper we provide a thorough discussion on the structure, consistency, stability, phase error, and accuracy of a new 4th-order space-time flux-conserving and neutrally stable CESE solver of an 1D scalar advection equation. The space-time stencil of this two-level explicit scheme is formed by one point at the upper time level and three points at the lower time level. Because it is associated with three independent mesh variables (the numerical analogues of the dependent variable and its 1st-order and 2ndorder spatial derivatives, respectively) and three equations per mesh point, the new scheme is referred to as the a(3) scheme. Through the von Neumann analysis, it is shown that the a(3) scheme is stable if and only if the Courant number is less than 0.5. Moreover, it is established numerically that the a(3) scheme is 4th-order accurate.
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.
Directory of Open Access Journals (Sweden)
Dhar A.K.
2015-05-01
Full Text Available Fourth order nonlinear evolution equations, which are a good starting point for the study of nonlinear water waves, are derived for deep water surface capillary gravity waves in the presence of second waves in which air is blowing over water. Here it is assumed that the space variation of the amplitude takes place only in a direction along which the group velocity projection of the two waves overlap. A stability analysis is made for a uniform wave train in the presence of a second wave train. Graphs are plotted for the maximum growth rate of instability wave number at marginal stability and wave number separation of fastest growing sideband component against wave steepness. Significant improvements are noticed from the results obtained from the two coupled third order nonlinear Schrödinger equations.
How to do mean field theory in Feynman gauge and doing it for U(1) with corrections to fourth order
Energy Technology Data Exchange (ETDEWEB)
Flyvbjerg, H.
1984-07-02
It is demonstrated how mean field theory with corrections from fluctuations may be applied to lattice gauge theories in covariant gauges. By fixing the gauge at tree level, the importance of fluctuations is decreased. This is understood as inclusion of terms of next-to-leading-order in d in the definition of the mean field tree approximation, d being the dimension of the lattice. The gauge group U(1) and Wilson's action are used as testing ground. Tree and one-loop results comparable to those previously obtained in axial gauge are obtained in for d=4. The next three correction terms to the free and plaquette energies are evaluated in Feynmann gauge. The truncated asympotic series thus obtained is compared to that of the ordinary weak coupling expansion. The mean field series gives, to those orders studied, a much better approximation. The location of phase transitions in 4d and 5d are predicted with 1% error bars.
Arshad, M.; Seadawy, Aly R.; Lu, Dianchen
2017-08-01
The higher-order nonlinear Schrödinger equation (NLSE) with fourth-order dispersion, cubic-quintic terms, self-steepening and nonlinear dispersive terms describes the propagation of extremely short pulses in optical fibers. In this paper, the elliptic function, bright and dark solitons and solitary wave solutions of higher-order NLSE are constructed by employing a modified extended direct algebraic method, which has important applications in applied mathematics and physics. Furthermore, we also present the formation conditions of the bright and dark solitons for this equation. The modulation instability is utilized to discuss the stability of these solutions, which shows that all solutions are exact and stable. Many other higher-order nonlinear evolution equations arising in applied sciences can also be solved by this powerful, effective and reliable method.
Zayed, Elsayed M. E.; Al-Nowehy, Abdul-Ghani; Elshater, Mona E. M.
2017-06-01
The (G^'/G)-expansion method, the improved Sub-ODE method, the extended auxiliary equation method, the new mapping method and the Jacobi elliptic function method are applied in this paper for finding many new exact solutions including Jacobi elliptic solutions, solitary solutions, singular solitary solutions, trigonometric function solutions and other solutions to the nonlinear Schrödinger equation with fourth-order dispersion and dual power law nonlinearity whose balance number is not positive integer. The used methods present a wider applicability for handling the nonlinear partial differential equations. A comparison of our new results with the well-known results is made. Also, we compare our results with each other yielding from these five integration tools.
Hou, Wei-Shu; Li, Hsiang-nan; Mishima, Satoshi; Nagashima, Makiko
2007-03-30
We study the effect from a sequential fourth generation quark on penguin-dominated two-body nonleptonic B meson decays in the next-to-leading order perturbative QCD formalism. With an enhancement of the color-suppressed tree amplitude and possibility of a new CP phase in the electroweak penguin amplitude, we can account better for A(CP)(B(0)-->K+ pi-)-A(CP)(B+-->K+ pi0). Taking |V(t's)V(t'b)| approximately 0.02 with a phase just below 90 degrees, which is consistent with the b-->sl+ l- rate and the B(s) mixing parameter Deltam(B)(s), we find a downward shift in the mixing-induced CP asymmetries of B(0)-->K(S)(pi 0) and phi(K)(S). The predicted behavior for B(0)-->rho(0)(K)(S) is opposite.
四阶忆阻考毕兹混沌振荡器研究%Research on Fourth-Order Memristive Colpitts Chaotic Oscillator
Institute of Scientific and Technical Information of China (English)
徐权; 林毅; 包伯成; 王宁
2016-01-01
By introducing first-order generalized memristor into a third-order Colpitts chaotic oscillator,a new fourth-order memristive Colpitts chaotic oscillator is proposed.The first-order generalized memristor is realized by a full-wave rectifier cascaded with a first-order parallel RC filter.The dynamical model of the memristive Colpitts chaotic oscillator is established,upon which the equilibrium point and its stability are studied.The results indicate that the fourth-order colpitts chaotic oscillator has only one unstable saddle-foci.Furthermore,the dynamics depending on circuit element parameter is investigated.The nonlinear phenomena of chaotic oscillations and periodic limit cycle are illustrated by combining the theoretical analy-sis,numerical simulation and experimental measurement.The experimental measurement and numerical simulation are consistent well,which well verifies the theoretical analysis.%通过在三阶考毕兹混沌振荡器中引入一阶广义忆阻器，提出了一种新颖的四阶忆阻考毕兹混沌振荡器，其中一阶广义忆阻器由二极管桥级联一阶 RC滤波器构成。建立了忆阻考毕兹混沌振荡器的动力学模型，研究了它的平衡点和稳定性，结果表明：四阶忆阻考毕兹混沌振荡器具有唯一的不稳定鞍焦。进一步开展了依赖于电路元件参数的动力学特性研究。采用理论分析、数值仿真和实验验证相结合的方法，对电路展现出的混沌吸引子、周期极限环等复杂的非线性现象进行了研究，实验结果与数值仿真结果相一致，较好地验证了理论分析结果。
基于四阶累积量的波束域MUSIC方法%A Better Fourth-Order Cumulant Method Using Beamspace MUSIC Algorithm
Institute of Scientific and Technical Information of China (English)
杜金香; 冯西安
2009-01-01
Aim. Refs. 4 through 7 are, in our opinion, somewhat deficient in either direction-of-arrival(DOA) statistical performance or computation load in the spatially correlated Gaussian noise environment. We propose a method that, we believe, is better. Section 2 of the full paper briefs the fourth-order cumulant methods in Refs.4 through 7 that use element space data. Section 3 explains in some detail our better fourth-order cumulant method using beamspace MUSIC algorithm. The core of section 4 is that our better method deals with the output signals of orthogonal beams and therefore leads to less computation cost. Section 5 presents the simulation results, which are given in Figs. 1 through 4, and compares the resolution and estimation precision of our method with those of previous methods. The comparison shows preliminarily that our method has better statistical performance than those methods that use element space data.%在非白噪声背景下,基于二阶统计量的高分辨方法性能较差.基于四阶累积量的高分辨方法能较好地抑制空间高斯噪声,但其运算量较大.为了解决这一矛盾,文章提出了一种基于四阶累积量的波束域MUSIC方法.仿真分析和实验结果表明,与阵元域四阶累积量MUSIC方法相比,论文所提方法降低了分辨门限,减小了估计偏差和均方根误差,同时减小了运算量.
Energy Technology Data Exchange (ETDEWEB)
Faizal, Mir
2013-12-18
In this Letter we will analyze the creation of the multiverse. We will first calculate the wave function for the multiverse using third quantization. Then we will fourth-quantize this theory. We will show that there is no single vacuum state for this theory. Thus, we can end up with a multiverse, even after starting from a vacuum state. This will be used as a possible explanation for the creation of the multiverse. We also analyze the effect of interactions in this fourth-quantized theory.
Palaniyappan, Sasi; Shimada, T; Shah, R C; Jung, D; Gautier, D C; Hegelich, B M; Fernandez, J C
2012-01-01
High-dynamic range isolation of the interference term and the non-interference term in the inverse Fourier-transformed spectral interferogram as required in Self-Referenced-Spectral-Interferometry (SRSI) for single-shot high-dynamic range laser pulse characterization is not always practically possible due to presence of the non-interference term over the entire temporal widow. Alternatively, we propose and demonstrate that one could directly obtain the single-shot Fourth-Order-Crosscorrelation (FOX) of the laser pulse to be characterized via SRSI (FOX-SRSI) from the interference term as the high-dynamic range laser contrast measurement, avoiding the need to isolate the interference and non-interference terms. As a consequence, the undesired contribution from the non-interference term limits the valid temporal window of the measurement. The single-shot FOX-SRSI result is consistent with the laser contrast measured independently using a multi-shot scanning third-order autocorrelator.
Ma, Junyan; Simos, T. E.
2016-11-01
A hybrid tenth algebraic order two-step method with vanished phase-lag and its first, second, third, fourth and fifth derivatives are obtained in this paper. We will investigate •the construction of the method •the local truncation error (LTE) of the newly obtained method. We will also compare the lte of the newly developed method with other methods in the literature (this is called the comparative LTE analysis) •the stability (interval of periodicity) of the produced method using frequency for the scalar test equation different from the frequency used in the scalar test equation for phase-lag analysis (this is called stability analysis) •the application of the newly obtained method to the resonance problem of the Schrödinger equation. We will compare its effectiveness with the efficiency of other known methods in the literature. It will be proved that the developed method is effective for the approximate solution of the Schrödinger equation and related periodical or oscillatory initial value or boundary value problems.
Laricchia, S; Fabiano, E; Della Sala, F
2014-01-01
We test Laplacian-level meta-generalized gradient approximation (meta-GGA) non-interacting kinetic energy functionals based on the fourth-order gradient expansion (GE4). We consider several well known Laplacian-level meta-GGAs from literature (bare GE4, modified GE4, and the MGGA functional of Perdew and Constantin [Phys. Rev. B \\textbf{75},155109 (2007)]), as well as two newly designed Laplacian-level kinetic energy functionals (named L0.4 and L0.6). First, a general assessment of the different functionals is performed, testing them for model systems (one-electron densities, Hooke's atom and different jellium systems), atomic and molecular kinetic energies as well as for their behavior with respect to density-scaling transformations. Finally, we assess, for the first time, the performance of the different functionals for Subsystem Density Functional Theory (DFT) calculations on non-covalently interacting systems. We find that the different Laplacian-level meta-GGA kinetic functionals may improve the descript...
Energy Technology Data Exchange (ETDEWEB)
Wang, Pan [State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876 (China); School of Science, Beijing University of Posts and Telecommunications, P.O. Box 122, Beijing 100876 (China); Tian, Bo, E-mail: tian.bupt@yahoo.com.cn [State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876 (China); School of Science, Beijing University of Posts and Telecommunications, P.O. Box 122, Beijing 100876 (China); Jiang, Yan; Wang, Yu-Feng [State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876 (China); School of Science, Beijing University of Posts and Telecommunications, P.O. Box 122, Beijing 100876 (China)
2013-02-15
For describing the dynamics of alpha helical proteins with internal molecular excitations, nonlinear couplings between lattice vibrations and molecular excitations, and spin excitations in one-dimensional isotropic biquadratic Heisenberg ferromagnetic spin with the octupole–dipole interactions, we consider an inhomogeneous generalized fourth-order nonlinear Schrödinger equation. Based on the Ablowitz–Kaup–Newell–Segur system, infinitely many conservation laws for the equation are derived. Through the auxiliary function, bilinear forms and N-soliton solutions for the equation are obtained. Interactions of solitons are discussed by means of the asymptotic analysis. Effects of linear inhomogeneity on the interactions of solitons are also investigated graphically and analytically. Since the inhomogeneous coefficient of the equation h=α x+β, the soliton takes on the parabolic profile during the evolution. Soliton velocity is related to the parameter α, distance scale coefficient and biquadratic exchange coefficient, but has no relation with the parameter β. Soliton amplitude and width are only related to α. Soliton position is related to β.
Directory of Open Access Journals (Sweden)
Lisa Herr
Full Text Available We present a new approach to model dose rate effects on cell killing after photon radiation based on the spatio-temporal clustering of DNA double strand breaks (DSBs within higher order chromatin structures of approximately 1-2 Mbp size, so called giant loops. The main concept of this approach consists of a distinction of two classes of lesions, isolated and clustered DSBs, characterized by the number of double strand breaks induced in a giant loop. We assume a low lethality and fast component of repair for isolated DSBs and a high lethality and slow component of repair for clustered DSBs. With appropriate rates, the temporal transition between the different lesion classes is expressed in terms of five differential equations. These allow formulating the dynamics involved in the competition of damage induction and repair for arbitrary dose rates and fractionation schemes. Final cell survival probabilities are computable with a cell line specific set of three parameters: The lethality for isolated DSBs, the lethality for clustered DSBs and the half-life time of isolated DSBs. By comparison with larger sets of published experimental data it is demonstrated that the model describes the cell line dependent response to treatments using either continuous irradiation at a constant dose rate or to split dose irradiation well. Furthermore, an analytic investigation of the formulation concerning single fraction treatments with constant dose rates in the limiting cases of extremely high or low dose rates is presented. The approach is consistent with the Linear-Quadratic model extended by the Lea-Catcheside factor up to the second moment in dose. Finally, it is shown that the model correctly predicts empirical findings about the dose rate dependence of incidence probabilities for deterministic radiation effects like pneumonitis and the bone marrow syndrome. These findings further support the general concepts on which the approach is based.
Kumar, Rajesh; Srivastava, Subodh; Srivastava, Rajeev
2017-07-01
For cancer detection from microscopic biopsy images, image segmentation step used for segmentation of cells and nuclei play an important role. Accuracy of segmentation approach dominate the final results. Also the microscopic biopsy images have intrinsic Poisson noise and if it is present in the image the segmentation results may not be accurate. The objective is to propose an efficient fuzzy c-means based segmentation approach which can also handle the noise present in the image during the segmentation process itself i.e. noise removal and segmentation is combined in one step. To address the above issues, in this paper a fourth order partial differential equation (FPDE) based nonlinear filter adapted to Poisson noise with fuzzy c-means segmentation method is proposed. This approach is capable of effectively handling the segmentation problem of blocky artifacts while achieving good tradeoff between Poisson noise removals and edge preservation of the microscopic biopsy images during segmentation process for cancer detection from cells. The proposed approach is tested on breast cancer microscopic biopsy data set with region of interest (ROI) segmented ground truth images. The microscopic biopsy data set contains 31 benign and 27 malignant images of size 896 × 768. The region of interest selected ground truth of all 58 images are also available for this data set. Finally, the result obtained from proposed approach is compared with the results of popular segmentation algorithms; fuzzy c-means, color k-means, texture based segmentation, and total variation fuzzy c-means approaches. The experimental results shows that proposed approach is providing better results in terms of various performance measures such as Jaccard coefficient, dice index, Tanimoto coefficient, area under curve, accuracy, true positive rate, true negative rate, false positive rate, false negative rate, random index, global consistency error, and variance of information as compared to other
Laricchia, Savio; Constantin, Lucian A; Fabiano, Eduardo; Della Sala, Fabio
2014-01-14
We tested Laplacian-level meta-generalized gradient approximation (meta-GGA) noninteracting kinetic energy functionals based on the fourth-order gradient expansion (GE4). We considered several well-known Laplacian-level meta-GGAs from the literature (bare GE4, modified GE4, and the MGGA functional of Perdew and Constantin (Phys. Rev. B 2007,75, 155109)), as well as two newly designed Laplacian-level kinetic energy functionals (L0.4 and L0.6). First, a general assessment of the different functionals is performed to test them for model systems (one-electron densities, Hooke's atom, and different jellium systems) and atomic and molecular kinetic energies as well as for their behavior with respect to density-scaling transformations. Finally, we assessed, for the first time, the performance of the different functionals for subsystem density functional theory (DFT) calculations on noncovalently interacting systems. We found that the different Laplacian-level meta-GGA kinetic functionals may improve the description of different properties of electronic systems, but no clear overall advantage is found over the best GGA functionals. Concerning the subsystem DFT calculations, the here-proposed L0.4 and L0.6 kinetic energy functionals are competitive with state-of-the-art GGAs, whereas all other Laplacian-level functionals fail badly. The performance of the Laplacian-level functionals is rationalized thanks to a two-dimensional reduced-gradient and reduced-Laplacian decomposition of the nonadditive kinetic energy density.
Institute of Scientific and Technical Information of China (English)
陈勇明; 杨晗
2008-01-01
The initial boundary value problem for the fourth-order wave equation utt+△2u+u=|t|p-1u is considered.The existence and uniqueness of global weak solutions is obtained by using the Galerkin method and the concept of stable set due to Sattinger.
Wainryb, Cecilia
2011-01-01
Approximately 300,000 child soldiers serve in various armed groups around the world, and become directly implicated in the perpetration of kidnappings, killings, and torture. Considering that children construct moral concepts and a sense of themselves as moral beings in the context of their everyday interactions with others, the concern with how…
Wainryb, Cecilia
2011-01-01
Approximately 300,000 child soldiers serve in various armed groups around the world, and become directly implicated in the perpetration of kidnappings, killings, and torture. Considering that children construct moral concepts and a sense of themselves as moral beings in the context of their everyday interactions with others, the concern with how…
Institute of Scientific and Technical Information of China (English)
王素云; 梁延堂
2001-01-01
在边值条件y(0)=y′(1)=y″(0)=y (1)=0下，讨论了方程 y″-f(y(x))=0三个正解的存在性。%The existence of three positive solutions of the fourth-order dffferential equation y -f(y(x))=0 is proved when y′(0)=y′(1)=y"(0)=y (1) =0.
Institute of Scientific and Technical Information of China (English)
陈维桓; 李海中
1999-01-01
用E.Cartan的等价方法,研究切触变换下四阶微分方程y(4)=f(x,y,y′,y″,y″′)的几何.%It is studied that the geometry of the differential equations of the fourth order y(4) = f(x, y,y′, y″, y′″) under contact transformations by E. Cartan's method of equivalence.
A New Image Denoising Algorithms of Fourth-order Partial Differential Equation%一种新的四阶偏微分方程的图像降噪算法
Institute of Scientific and Technical Information of China (English)
杨薇; 王楠
2012-01-01
提出一种基于四阶偏微分方程的图像降噪算法——耦合梯度保真项的四阶偏微分方程的图像降噪算法,实验结果验证了算法的有效性.%This paper advances the fourth-order partial differential equation coupling gradient fidelity term image denoising algorithms.The experiment result shows the efficiency of the algorithm.
Institute of Scientific and Technical Information of China (English)
郭茂银; 田有先
2011-01-01
四阶偏微分方程(PDE)图像去噪方法具有良好的去噪性能,但该类方法计算量大,耗时长.为提高算法的快速性和有效性,提出一种高效并行的四阶PDE图像去噪算法.该方法基于MPI并行环境,通过分析四阶PDE离散化后差分方程求解的并行性,对噪声图像进行条状重叠的数据划分,采用并行方式对图像去噪,极大地降低了运行时间.%Image noise removal methods based on the fourth-order Partial Differential Equations (PDE) show their good denoising performance, but they also have some problems such as the great amount of calculation and long consuming time. In order to improve the speed and efficiency of the algorithm, an efficient parallel algorithm is proposed in this paper, which can reduce the running time greatly by analyzing the parallelism of the discrete fourth-order PDE and dividing the noise image into overlapping strips in the parallel environment of MPL.
Institute of Scientific and Technical Information of China (English)
彭刚; 石海平
2013-01-01
应用临界点理论中的山路引理,研究了一类四阶非线性差分方程周期解和次调和解的存在性问题.通过把方程解的存在性转化为某个泛函临界点的存在性,获得了一类四阶非线性差分方程周期解和次调和解的存在性和多重性的一些充分条件,给出周期解和次调和解的存在性和多重性准则.%By using the notable Mountain Pass Lemma of critical point theory,some sufficient conditions for the existence and multiplicity of periodic and subharmonic solutions to a class of fourth-order nonlinear difference equations are obtained.The proof is based on the Mountain Pass Lemma in combination with variational technique.A practicable method to solve the existence and multiplicity of periodic and subharmonic solutions for fourth-order nonlinear forward and backward difference equations is given.
Institute of Scientific and Technical Information of China (English)
周千
2014-01-01
建立了一种描述图像平滑度的泛函，并推导出新的四阶偏微分方程图像去噪模型，在有效去噪的同时，较好地保持了图像的特征。由于该方法得到的图像是分段线性图像，避免了二阶偏微分方程处理图像常出现的“阶梯”效应，同时，和同类的四阶偏微分方程去噪模型相比，其处理结果不会出现“斑”点，因此视觉效果更加理想。最后通过实验证明了该方法的有效性。%A new fourth-order partial differential equation (PDE )is proposed to remove noises,which can remove noises while preserving edges well.The results of the proposed PDEs processed images are piecewise planar images.Piecewise pla-nar images look more natural than step images that second order PDEs nonlinear diffusion uses to approximate an observed image.That means the proposed PDEs are able to avoid the blocky effects widely seen in images processed by second order nonlinear diffusion,achieving the degree of noise removal and edge preservation comparable to second order PDEs.Other fourth-order partial differential equations need despeckle algorithms to remove speckles after processing,while the PDEs pro-posed don’t have such problem.Finally,the validity of the proposed model is proved through the experiment.
Killing tensors in pp-wave spacetimes
Energy Technology Data Exchange (ETDEWEB)
Keane, Aidan J [87 Carlton Place, Glasgow G5 9TD, Scotland (United Kingdom); Tupper, Brian O J, E-mail: aidan@countingthoughts.co, E-mail: bt32@rogers.co [Department of Mathematics and Statistics, University of New Brunswick, Fredericton, New Brunswick, E3B 5A3 (Canada)
2010-12-21
The formal solution of the second-order Killing tensor equations for the general pp-wave spacetime is given. The Killing tensor equations are integrated fully for some specific pp-wave spacetimes. In particular, the complete solution is given for the conformally flat plane wave spacetimes and we find that irreducible Killing tensors arise for specific classes. The maximum number of independent irreducible Killing tensors admitted by a conformally flat plane wave spacetime is shown to be six. It is shown that every pp-wave spacetime that admits an homothety will admit a Killing tensor of Koutras type and, with the exception of the singular scale-invariant plane wave spacetimes, this Killing tensor is irreducible.
CONVEF-based Fourth-order Anisotropic Diffusion for Image Denoising%基于CONVEF的四阶各向异性扩散及图像去噪
Institute of Scientific and Technical Information of China (English)
王元全; 任文琦
2013-01-01
偏微分方程在图像去噪中有广泛的应用.传统的二阶偏微分方程虽然具有较好的去噪效果,但是处理得到的结果容易产生阶梯效应,这种现象会引起后续图像处理的误判断.You和Kaveh提出了四阶偏微分方程,该模型可以有效的去除阶梯效应,但由于该算法是一个各向同性的滤波算法,因此图像的边缘保护能力有所降低,使去噪结果中边缘和纹理等细节信息丢失.针对以上缺点,提出了基于卷积虚拟电子场(CONVEF)的四阶偏微分方程.新的模型降低了图像在边缘方向的扩散,得到一个有效的各向异性扩散模型,从而在去噪的同时可以更好的保护图像的边缘、纹理等细节特征.%Partial differential equations (PDEs) have been justified as effective tools for image denoising.The second-order PDEs are effective for image noise removal but they can lead to staircase effects.These staircases can be falsely detected as edges in the successive image processing.The fourth-order PDE introduced by You and Kaveh can alleviate the staircase effect,but it is an isotropic filter and its edge and texture preserving ability is not satisfactory.In light of this,the convolutional virtual electric field (CONVEF) into the fourth-order PDE for images restoration is introduced.Since the CONVEF based fourth-order model possesses anisotropic properties over the image features,it leads to improvement on noise removal and edge and texture preserving over the original model.
Institute of Scientific and Technical Information of China (English)
沈鑫; 束洪春; 曹敏; 李剑; 翟少磊; 张林山; 林中爱
2016-01-01
Ultra-High-Frequency (UHF) method for detection of partial discharge (PD) has been widely appreciated and studied. It can effectively avoid the low-frequency electromagnetic interference and has the advantage of high sensitivi-ty. Mostly, the UHF antennas used for PD detection have large size, and the characters are narrow frequency pand, this paper designs a Hilbert fractal antenna with multi-frequency and small size for UHF PD online monitoring of transform-er. In the existing basic principle of fourth-order Hilbert four-order fractal antenna technology, the planar antenna is mod-eled by Ansoft Designer. Based on simulation calculation, geometric parameters of the antenna were selected and the fourth order Hilbert fractal antenna was designed. The partial discharge UHF signal of four typical defects for oil-paper insulation was measured by the optimized fourth order Hilbert fractal antenna designed in the laboratory. Experimental results show that the designed antenna is qualified for online PD UHF monitoring.%针对传统局部放电超高频检测天线频带窄、尺寸大的缺点，设计了一种用于在线监测变压器局部放电的多频带、尺寸小的超高频天线。通过研究了分形理论和天线测量原理，在现有四阶Hilbert分形曲线的技术基础上，利用Ansoft Designer电磁场仿真软件建立天线模型，并通过仿真计算，优化配置了天线的几何参数，设计制造了平板结构的四阶Hilbert分形局放超高频监测天线。利用设计的四阶Hilbert分形天线对四种典型油纸绝缘缺陷进行局部放电超高频信号监测，并采用文中设计的天线与现有技术的三阶Penao分形天线、三阶Hilbert分形天线在实验室进行局部放电对比测量，分析了天线实测效果，实验结果表明该天线能够有效应用于变压器局部放电超高频在线监测。
Kataev, A L
2015-01-01
The semi-analytical $O(\\alpha_s^4)$ expression for the renormalization group $\\beta$-function in the ${\\rm{V}}$-scheme is obtained in the case of the $SU(N_c)$ gauge group. In the process of calculations we use the existing information about the three-loop perturbative approximation for the QCD static potential, evaluated in the $\\rm{\\overline{MS}}$-scheme. The comparison of the numerical values of the third and fourth coefficients for the QCD RG $\\beta$- functions in the gauge-independent ${\\rm{V}}$- and $\\rm{\\overline{MS}}$-schemes and in minimal MOM scheme in the the Landau gauge is presented. The phenomenologically-oriented comparisons for the coefficients of $O(\\alpha_s^4)$ expression for the $e^+e^-$-annihilation R-ratio in these schemes are presented. It is shown, that taking into account of these QCD contributions are of vital importance and lead to the drastic decrease of the scheme-dependence ambiguities of the fourth-order perturbative QCD approximations for the $e^+e^-$ annihilation R-ratio for th...
Kunz, Julia Vanessa; Hensley, Robert; Brase, Lisa; Borchardt, Dietrich; Rode, Michael
2017-01-01
River networks exhibit a globally important capacity to retain and process nitrogen. However direct measurement of in-stream removal in higher order streams and rivers has been extremely limited. The recent advent of automated sensors has allowed high frequency measurements, and the development of new passive methods of quantifying nitrogen uptake which are scalable across river size. Here we extend these methods to higher order streams with anthropogenically elevated nitrogen levels, substantial tributaries, complex input signals, and multiple N species. We use a combination of two station time-series and longitudinal profiling of nitrate to assess differences in nitrogen processing dynamics in a natural versus a channelized impounded reach with WWTP effluent impacted water chemistry. Our results suggest that net mass removal rates of nitrate were markedly higher in the unmodified reach. Additionally, seasonal variations in temperature and insolation affected the relative contribution of assimilatory versus dissimilatory uptake processes, with the latter exhibiting a stronger positive dependence on temperature. From a methodological perspective, we demonstrate that a mass balance approach based on high frequency data can be useful in deriving quantitative uptake estimates, even under dynamic inputs and lateral tributary inflow. However, uncertainty in diffuse groundwater inputs and more importantly the effects of alternative nitrogen species, in this case ammonium, pose considerable challenges to this method.
Energy Technology Data Exchange (ETDEWEB)
Busche, M J
2000-08-11
This document describes the software developed for use in calculating K, the 4th order parameter tensor used in ALE3D's anisotropic plasticity model. The multi-scale modeling method developed for this calculation begins with orientation imaging microscopy (OIM) data. The program OIMA3D characterizes the sizes and crystal orientation of the grains found in this data and then determines element orientations for a representative 3D mesh. A shell script, MAKEJOBS, then creates the necessary files to run six ALE3D simulations using this mesh. The results of these simulations are then read by SVD{_}K, a Matlab script, and K is calculated from this information.
Irreducible Killing Tensors from Third Rank Killing-Yano Tensors
Popa, Florian Catalin; Tintareanu-Mircea, Ovidiu
2006-01-01
We investigate higher rank Killing-Yano tensors showing that third rank Killing-Yano tensors are not always trivial objects being possible to construct irreducible Killing tensors from them. We give as an example the Kimura IIC metric were from two rank Killing-Yano tensors we obtain a reducible Killing tensor and from third rank Killing-Yano tensors we obtain three Killing tensors, one reducible and two irreducible.
Heil, Konstantin; Moroianu, Andrei; Semmelmann, Uwe
2017-07-01
We show that Killing tensors on conformally flat n-dimensional tori whose conformal factor only depends on one variable, are polynomials in the metric and in the Killing vector fields. In other words, every first integral of the geodesic flow polynomial in the momenta on the sphere bundle of such a torus is linear in the momenta.
Institute of Scientific and Technical Information of China (English)
王瑜; 张慧妍
2012-01-01
A new denoising diffusion model is proposed for fluorescence microscopic images, in which fourth-order partial differential equations (PDEs) and contrast enhancement are utilized to overcome the blocky effect and false edges usually caused by second-order PDEs. Compared with second-order PDEs model, the proposed model shows superior performance in terms of both objective criteria and subjective human vision via processing simulated and experimental noisy images.%提出一种用于荧光显微图像去噪扩散模型的算法,该算法针对二阶偏微分方程去噪模型易引起的“块效应”和伪边缘等问题,采用正则化方法,利用四阶偏微分方程,同时融合对比度增强技术设计去噪模型.与二阶偏微分方程扩散模型相比,该算法不仅使去噪图像看起来更加自然清晰,而且在峰值信噪比和结构相似度等客观评价方法下也取得了更加满意的结果.
Institute of Scientific and Technical Information of China (English)
程锐; 姜润翔; 龚沈光
2015-01-01
为实现低信噪比情况下微弱的船舶轴频电场信号的有效检测 ,提出了一种结合经验模态分解(empiri-cal mode decomposition ,EMD)和四阶混合累积量对角切片滑动功率谱的方法.首先 ,利用EMD将信号自适应地进行子带分解 ,对得到的本征模态函数(intrinsic mode functions ,IM F)采用相关系数准则进行筛选 ;然后 ,利用高阶累积量可抑制高斯色噪声的特性 ,计算各有效IM F分量的四阶混合累积量对角切片的功率谱 ,并进行了多子带中的滑动检测.实测数据处理结果表明 :该方法具有较好的应用价值.%In order to implement effective detection of weak ship shaft-rate electric field signal under low signal to noise ratio (SNR) ,a method combining empirical mode decomposition (EMD) with sli-ding power spectrum of fourth-order mixed cumulant diagonal slice is proposed .Firstly ,EMD method is employed to adaptively decompose the signal into a set of intrinsic mode functions (IMFs) ,from which the valid ones are selected according to correlation coefficient criterion .Then ,by exploiting the property of higher order cumulant which can suppress Gaussian colored noise ,power spectrum of fourth-order mixed cumulant diagonal slice of selected IM Fs is calculated ,w hich is then used for slid-ing detection in multiple sub-bands .The result of processing practical data illustrates that this method is of great value in application .
Gravitational Lensing by Fourth Order Gravity
Stabile, A
2011-01-01
For a general class of analytic $f(R,R_{\\alpha\\beta}R^{\\alpha\\beta},R_{\\alpha\\beta\\gamma\\delta}R^{\\alpha\\beta\\gamma\\delta})$ we discuss the gravitational lensing in the Newtonian Limit of theory. From the properties of Gauss Bonnet invariant it is successful to consider only two curvature invariants between the Ricci and Riemann tensor. Then we analyze the dynamics of photon embedded in a gravitational field of a generic $f(R,R_{\\alpha\\beta}R^{\\alpha\\beta})$-Gravity. The metric is time independent and spherically symmetric. The metric potentials are Schwarzschild-like, but there are two additional Yukawa terms linked to derivatives of $f$ with respect to two curvature invariants. Considering the case of a point-like lens, and after of a generic matter distribution of lens, we study the deflection angle and the images angular position. Though the additional Yukawa terms in the gravitational potential modifies dynamics with respect to General Relativity, the geodesic trajectory of photon is unaffected by the mo...
Spectral estimates for periodic fourth order operators
Badanin, Andrey
2008-01-01
We consider the operator $H={d^4dt^4}+{ddt}p{ddt}+q$ with 1-periodic coefficients on the real line. The spectrum of $H$ is absolutely continuous and consists of intervals separated by gaps. We describe the spectrum of this operator in terms of the Lyapunov function, which is analytic on a two-sheeted Riemann surface. On each sheet the Lyapunov function has the standard properties of the Lyapunov function for the scalar case. We describe the spectrum of $H$ in terms of periodic, antiperiodic eigenvalues, and so-called resonances. We prove that 1) the spectrum of $H$ at high energy has multiplicity two, 2) the asymptotics of the periodic, antiperiodic eigenvalues and of the resonances are determined at high energy, 3) for some specific $p$ the spectrum of $H$ has an infinite number of gaps, 4) the spectrum of $H$ has small spectral band (near the beginner of the spectrum) with multiplicity 4 and its asymptotics are determined as $p\\to 0, q=0$.
On a Fourth-order Eigenvalue Problem
Institute of Scientific and Technical Information of China (English)
无
2000-01-01
@@ We consider the existence of positive solutions for the equation d4y/dx4-λf(x,y(x))=0,(1) with one of the following sets of boundary value conditions y(0)=y(1)=y"(0)=y"(1)=0,(2) y(0)=y′(1)=y"(0)=y"′(1)=0.(3)
Energy Technology Data Exchange (ETDEWEB)
Yang, Jin-Wei; Gao, Yi-Tian, E-mail: gaoyt163@163.com; Wang, Qi-Min; Su, Chuan-Qi; Feng, Yu-Jie; Yu, Xin
2016-01-15
In this paper, a fourth-order variable-coefficient nonlinear Schrödinger equation is studied, which might describe a one-dimensional continuum anisotropic Heisenberg ferromagnetic spin chain with the octuple–dipole interaction or an alpha helical protein with higher-order excitations and interactions under continuum approximation. With the aid of auxiliary function, we derive the bilinear forms and corresponding constraints on the variable coefficients. Via the symbolic computation, we obtain the Lax pair, infinitely many conservation laws, one-, two- and three-soliton solutions. We discuss the influence of the variable coefficients on the solitons. With different choices of the variable coefficients, we obtain the parabolic, cubic, and periodic solitons, respectively. We analyse the head-on and overtaking interactions between/among the two and three solitons. Interactions between a bound state and a single soliton are displayed with different choices of variable coefficients. We also derive the quasi-periodic formulae for the three cases of the bound states.
Rucker, Rudy
2014-01-01
""This is an invigorating book, a short but spirited slalom for the mind."" - Timothy Ferris, The New York Times Book Review ""Highly readable. One is reminded of the breadth and depth of Hofstadter's Gödel, Escher, Bach."" - Science""Anyone with even a minimal interest in mathematics and fantasy will find The Fourth Dimension informative and mind-dazzling... [Rucker] plunges into spaces above three with a zest and energy that is breathtaking."" - Martin Gardner ""Those who think the fourth dimension is nothing but time should be encouraged to read The Fourth Dimension, along with anyone else
Institute of Scientific and Technical Information of China (English)
王鹏; 邱天爽; 李景春; 谭海峰
2015-01-01
A novel joint multi-parameters estimation method for near-field narrow-band sources is proposed.The frequencies,DOAs (direction of arrival,DOA)and ranges of near-field sources are directly estimated by the eigenvalues and the eigenvectors of the constructed fourth-order cumulant matrices.The proposed method does not require any peak search and can be applied to arbitrary Gaussian noise environment.Compared with several existing methods,the proposed method avoids the loss of array aperture and reduces the computational complexity.The comprehensive simulation results demonstrate the validity of this new method.%提出了一种近场窄带信源多参数联合估计新方法，通过所构造四阶累积量矩阵的特征值及其特征向量就可以直接获得近场源频率、方位及距离三维参数的联合估计，无须峰值搜索，适用于任意高斯噪声环境。与现有方法相比，所提方法有效地避免了阵列孔径损失，而且算法简单高效。仿真综合结果表明了新方法的有效性。
Schaefle, Nathaniel; Sharp, Robert
2005-05-08
The metalloporphyrins, Me-TSPP [Me=Cr(III), Mn(III), Mn(II), Fe(III), and TSPP=meso-(tetra-p-sulfonatophenyl)porphyrin], which possess electron spins S=3/2, 2, 5/2, and 5/2, respectively, comprise an important series of model systems for mechanistic studies of NMR paramagnetic relaxation enhancement (NMR-PRE). For these S>1/2 spin systems, the NMR-PRE depends critically on the detailed form of the zero-field splitting (zfs) tensor. We report the results of experimental and theoretical studies of the NMR relaxation mechanism associated with Fe(III)-TSPP, a spin 5/2 complex for which the overall zfs is relatively large (D approximately = 10 cm(-1)). A comparison of experimental data with spin dynamics simulations shows that the primary determinant of the shape of the magnetic relaxation dispersion profile of the water proton R1 is the tetragonal fourth-order component of the zfs tensor. The relaxation mechanism, which has not previously been described, is a consequence of zfs-induced mixing of the spin eigenfunctions of adjacent Kramers doublets. We have also investigated the magnetic-field dependence of electron-spin relaxation for S=5/2 in the presence of a large zfs, such as occurs in Fe(III)-TSPP. Calculations show that field dependence of this kind is suppressed in the vicinity of the zfs limit, in agreement with observation.
Symmetry operators of Killing spinors and superalgebras in AdS_5
Ertem, Ümit
2016-01-01
We construct the first-order symmetry operators of Killing spinor equation in terms of odd Killing-Yano forms. By modifying the Schouten-Nijenhuis bracket of Killing-Yano forms, we show that the symmetry operators of Killing spinors close into an algebra in AdS_5 spacetime. Since the symmetry operator algebra of Killing spinors corresponds to a Jacobi identity in extended Killing superalgebras, we investigate the possible extensions of Killing superalgebras to include higher-degree Killing-Ya...
Institute of Scientific and Technical Information of China (English)
王瑜; 薛红
2012-01-01
荧光显微图像由于光学成像系统的自身物理缺陷,光电转换,样本组织结构以及人为误差等因素的影响,噪声无法避免,为此,一种基于方向四阶偏微分方程的荧光显微图像去噪方法被提出,主要考虑两个方面,一是基于变分方法,二是控制滤波模型的扩散方向.在人工合成和真实荧光显微图像上进行的实验结果表明,同传统二阶偏微分方程扩散模型相比,应用所提出的方法进行去噪,不管是主观视觉,还是客观评价,均表现出了更好的性能.%Noise in the fluorescence microscopic images can' t be avoided because of imperfect optical imaging system, photoelectric conversion, specimen tissue structure and human errors etc during the course of optical imaging. Therefore, a new denoising method is proposed based on oriented fourth-order partial-differential equations (PDEs) for fluorescence microscopic images, in which two aspects are considered. One is based on variational method, the other is based on controlling diffusion directioa Experimental results show that the proposed method not only makes the denoised images subjectively more natural and clearer, but also achieves better performance in terms of objective criterion such as peak signal to noise ratio (PSNR) and the structural similarity (SSIM) compared with the related second-order PDEs diffusion models.
National Research Council Canada - National Science Library
2015-01-01
...". There are, however, several statutory and court-made exceptions to this bar on appellate review. Recently, in Barlow v Colgate Palmolive Co , the Fourth Circuit sitting en banc held that 1447(d...
The Geometry of D=11 Killing Spinors
Gauntlett, J P; Gauntlett, Jerome P.; Pakis, Stathis
2003-01-01
We propose a way to classify all supersymmetric configurations of D=11 supergravity using the G-structures defined by the Killing spinors. We show that the most general bosonic geometries admitting a Killing spinor have at least an SU(5) or an (Spin(7)\\ltimes R^8)x R structure, depending on whether the Killing vector constructed from the Killing spinor is timelike or null, respectively. In the former case we determine what kind of SU(5) structure is present and show that almost all of the form of the geometry is determined by the structure. We also deduce what further conditions must be imposed in order that the equations of motion are satisfied. We illustrate the formalism with some known solutions and also present some new solutions including a rotating generalisation of the resolved membrane solutions and generalisations of the recently constructed D=11 Godel solution.
Theriocide: Naming Animal Killing
Directory of Open Access Journals (Sweden)
Piers Beirne
2014-08-01
Full Text Available In this essay I recommend ‘theriocide’ as the name for those diverse human actions that cause the deaths of animals. Like the killing of one human by another, theriocide may be socially acceptable or unacceptable, legal or illegal. It may be intentional or unintentional and may involve active maltreatment or passive neglect. Theriocide may occur one-on-one, in small groups or in large-scale social institutions. The numerous and sometimes intersecting sites of theriocide include intensive rearing regimes; hunting and fishing; trafficking; vivisection; militarism; pollution; and human-induced climate change. If the killing of animals by humans is as harmful to them as homicide is to humans, then the proper naming of such deaths offers a remedy, however small, to the extensive privileging of human lives over those of other animals. Inevitably, the essay leads to a shocking question: Is theriocide murder?
Institute of Scientific and Technical Information of China (English)
杨怀英; 唐小平; 刘宽厚
2014-01-01
The Runge-Kutta method is a common technology for solving the Ordinary Differential Equations ( ODE) and is characterized by high precision, strong stability and some other advantages. In this paper, based on a new four-stage fourth order Runge-Kutta meth-od, the authors first combined the four-stage calculation formula with a new two-stage iteration formula, thus achieving the purpose of saving computational memory. And then, the time high-order discrete form of the acoustic wave equation was derived and, in combina-tion with the pseudospectral method, some researches on the high-accuracy and high-definition acoustic wave field simulation technology of the four-stage fourth order Runge-Kutta time high-order pseudospectral method were carried out, with an investigation of the stability and dispersion of the method. Finally, homogeneous media, layered media and lens model were selected for wave field simulation test. The simulation results show that the four-stage fourth order Runge-Kutta time high-order pseudospectral method has strong stability and high wave field definition and can effectively remove the dispersion and adapt itself to large simulation parameter range, thus being a high efficient wave field simulation method with great application potential.%龙格-库塔法是常用于求解常微分方程（ ODE）的一项技术，该技术具有精度高、稳定性强等特点。笔者以一种新的四级四阶龙格-库塔法为基础，先将其四级计算公式合并为新的两级计算迭代公式，从而达到节约计算内存的目的；再以此为基础推导出声波方程的时间高阶离散形式，并与伪谱法技术相结合，研究四级四阶龙格-库塔时间高阶伪谱法声波高精度、高清晰度的波场模拟技术，进而研究该方法的稳定性与频散特性；最后，分别选取均匀介质、层状介质和透镜体模型进行波场模拟试验。模拟结果表明，该方法具有稳定性强、能有效去除
Fourth Generation War: Paradigm for Change
2005-06-01
frustrated by the advantages that the weak acquire through 4GW, are also within the genre of the Fourth Generation. Terrorism is the strategy and tactic of...for SF. In order to examine these factors a brief overview of SF is necessary. 1. What Makes the SOF As per the techno-- thriller author Tom
"Researching" with Third- and Fourth-Graders.
Liston, Barbara
1970-01-01
In order to instill in children the skills which will be basic to their school experience, words implying a process (such as "hemp,""parasite," and "vanilla") may be "researched" by third and fourth graders through the use of a dictionary, an encyclopedia, a supplementary book on the subject, and an interview with an adult. The child makes a…
基于四阶累积量的共形阵列波达方向估计算法%DOA estimation algorithm for conformal array based on fourth-order cumulants
Institute of Scientific and Technical Information of China (English)
齐子森; 郭英; 王布宏; 王永良
2011-01-01
The estimation of the source polarization always accompanied with the direction-of-arrival （DOA） estimation because of the polarization diversity of conformal array manifold. A blind DOA estimation method with polarization diversity is proposed in this paper taking account of the characteristic of conformal array antenna DOA estimation when the incident signals are assumed to be statistically independent non-Gaussian narrowband random processes. It is shown how the extended-array due to fourth-order cumulants of the array outputs and estimation of signal parameters via rotational invariance techniques （ESPRIT） algorithm to decouple the DOA and signal polarization parameters. The proposed method achieves high-resolution 2D DOA estimation without no source polarization and the element pattern. The new method has widely applications in a variety of conformal carriers such as cylindrical, conical and spherical carriers. The procedure is given and the mechanism is derived by taking cylindrical conformal array antenna as an example. Finally, Monte Carlo simulations are provided to illustrate the effectiveness of the proposed algorithm.%由于共形天线阵列流形的多极化特性（PolarizationDiversity），共形阵列天线的信源方位估计需要与信源的极化状态联合进行。分析总结共形阵列天线波达方向（DOA）估计特点的基础上，针对窄带远场非高斯独立信源，提出了一种共形阵列天线盲极化DOA估计算法。该算法利用四阶累积量对阵列口径的扩展性，结合旋转不变子空间（ESPRIT）算法，在信源极化状态未知条件下实现了共形阵列天线的高分辨DOA估计。所提算法的方位估计不需要天线单元方向图以及信源极化状态的任何信息，适用于多种常用共形载体（锥面、柱面以及球面共形载体），具有较为广泛的应用环境。以柱面共形阵列天线DoA估计为例，详细推导了算法机理，给出了算
The Naturalness of the Fourth SM Family
Sultansoy, S
2009-01-01
The necessity of the fourth family follows from the SM basics. According to flavor democracy the Dirac masses of the fourth SM family fermions are almost equal with preferable value 450 GeV, which corresponds to common (for all fundamental fermions) Yukawa coupling equal to SU(2) gauge coupling gW. In principle, one expect u4 a little bit lighter than d4, while nu4 could be essentially lighter than l4 due to Majorana mass terms for right-handed components of neutrinos. Obviously, the fourth family quarks will be copiously produced at the LHC. However, the first indication of the fourth SM family may be provided by early Higgs boson observation due to almost an order enhancement of the gluon fusion to Higgs cross-section. For the same reason the Tevatron still has a chance to observe the Higgs boson before the LHC. Concerning the fourth family leptons, in general, best place will be NLC/CLIC. However, for some mass regions and MNS matrix elements double discovery of both the nu4 and H could be possible at the ...
Integrable Conformal Field Theory in Four Dimensions and Fourth-Rank Geometry
Tapia, V
1993-01-01
We consider the conformal properties of geometries described by higher-rank line elements. A crucial role is played by the conformal Killing equation (CKE). We introduce the concept of null-flat spaces in which the line element can be written as ${ds}^r=r!d\\zeta_1\\cdots d\\zeta_r$. We then show that, for null-flat spaces, the critical dimension, for which the CKE has infinitely many solutions, is equal to the rank of the metric. Therefore, in order to construct an integrable conformal field theory in 4 dimensions we need to rely on fourth-rank geometry. We consider the simple model ${\\cal L}={1\\over 4} G^{\\mu\
Analysing the Wrongness of Killing
DEFF Research Database (Denmark)
Di Nucci, Ezio
2014-01-01
This article provides an in-depth analysis of the wrongness of killing by comparing different versions of three influential views: the traditional view that killing is always wrong; the liberal view that killing is wrong if and only if the victim does not want to be killed; and Don Marquis‟ future...... of value account of the wrongness of killing. In particular, I illustrate the advantages that a basic version of the liberal view and a basic version of the future of value account have over competing alternatives. Still, ultimately none of the views analysed here are satisfactory; but the different...... reasons why those competing views fail provide important insights into the ethics of killing....
Killing Spinors -- Beyond Supergravity
Palomo-Lozano, Alberto
2012-01-01
This is a doctoral thesis on the application of techniques originally developed in the programme of characterisation of supersymmetric solutions to Supergravity theories, to finding alternative backgrounds. We start by discussing the concept of a Killing spinor, and how these are paramount to the process of classifying of these aforementioned supersymmetric solutions. Moreover, these geometric objects also have applications when considered in different scenarios (the 'beyond' in the title). In particular, techniques based on a parallelising rule for a spinorial field can be used for obtaining solutions to Einstein-Maxwell-De Sitter theories, as well as a (partial) classification of Lorentzian Einstein-Weyl manifolds, a problem of geometrical interest. The annexe contain an introduction and summary in Spanish language. The appendices discuss the tensorial and spinorial conventions employed, some relevant geometrical information on the scalar manifolds for the matter contents of interest, as well as for the nul...
Amabile, T M
1998-01-01
In today's knowledge economy, creativity is more important than ever. But many companies unwittingly employ managerial practices that kill it. How? By crushing their employees' intrinsic motivation--the strong internal desire to do something based on interests and passions. Managers don't kill creativity on purpose. Yet in the pursuit of productivity, efficiency, and control--all worthy business imperatives--they undermine creativity. It doesn't have to be that way, says Teresa Amabile. Business imperatives can comfortably coexist with creativity. But managers will have to change their thinking first. Specifically, managers will need to understand that creativity has three parts: expertise, the ability to think flexibly and imaginatively, and motivation. Managers can influence the first two, but doing so is costly and slow. It would be far more effective to increase employees' intrinsic motivation. To that end, managers have five levers to pull: the amount of challenge they give employees, the degree of freedom they grant around process, the way they design work groups, the level of encouragement they give, and the nature of organizational support. Take challenge as an example. Intrinsic motivation is high when employees feel challenged but not overwhelmed by their work. The task for managers, therefore, becomes matching people to the right assignments. Consider also freedom. Intrinsic motivation--and thus creativity--soars when managers let people decide how to achieve goals, not what goals to achieve. Managers can make a difference when it comes to employee creativity. The result can be truly innovative companies in which creativity doesn't just survive but actually thrives.
Killing Symmetry on Finsler Manifold
Ootsuka, Takayoshi; Ishida, Muneyuki
2016-01-01
Killing vector fields $K$ are defined on Finsler manifold. The Killing symmetry is reformulated simply as $\\delta K^\\flat =0$ by using the Killing non-linear 1-form $K^\\flat$ and the spray operator $\\delta$ with the Finsler non-linear connection. $K^\\flat$ is related to the generalization of Killing tensors on Finsler manifold, and the condition $\\delta K^\\flat =0$ gives an analytical method of finding higher derivative conserved quantities, which may be called hidden conserved quantities. We show two examples: the Carter constant on Kerr spacetime and the Runge-Lentz vectors in Newtonian gravity.
Phantom metrics with Killing spinors
Directory of Open Access Journals (Sweden)
W.A. Sabra
2015-11-01
Full Text Available We study metric solutions of Einstein–anti-Maxwell theory admitting Killing spinors. The analogue of the IWP metric which admits a space-like Killing vector is found and is expressed in terms of a complex function satisfying the wave equation in flat (2+1-dimensional space–time. As examples, electric and magnetic Kasner spaces are constructed by allowing the solution to depend only on the time coordinate. Euclidean solutions are also presented.
2000-09-01
VLT YEPUN Joins ANTU, KUEYEN and MELIPAL It was a historical moment last night (September 3 - 4, 2000) in the VLT Control Room at the Paranal Observatory , after nearly 15 years of hard work. Finally, four teams of astronomers and engineers were sitting at the terminals - and each team with access to an 8.2-m telescope! From now on, the powerful "Paranal Quartet" will be observing night after night, with a combined mirror surface of more than 210 m 2. And beginning next year, some of them will be linked to form part of the unique VLT Interferometer with unparalleled sensitivity and image sharpness. YEPUN "First Light" Early in the evening, the fourth 8.2-m Unit Telescope, YEPUN , was pointed to the sky for the first time and successfully achieved "First Light". Following a few technical exposures, a series of "first light" photos was made of several astronomical objects with the VLT Test Camera. This instrument was also used for the three previous "First Light" events for ANTU ( May 1998 ), KUEYEN ( March 1999 ) and MELIPAL ( January 2000 ). These images served to evaluate provisionally the performance of the new telescope, mainly in terms of mechanical and optical quality. The ESO staff were very pleased with the results and pronounced YEPUN fit for the subsequent commissioning phase. When the name YEPUN was first given to the fourth VLT Unit Telescope, it was supposed to mean "Sirius" in the Mapuche language. However, doubts have since arisen about this translation and a detailed investigation now indicates that the correct meaning is "Venus" (as the Evening Star). For a detailed explanation, please consult the essay On the Meaning of "YEPUN" , now available at the ESO website. The first images At 21:39 hrs local time (01:39 UT), YEPUN was turned to point in the direction of a dense Milky Way field, near the border between the constellations Sagitta (The Arrow) and Aquila (The Eagle). A guide star was acquired and the active optics system quickly optimized the
Killing, letting die and euthanasia.
Husak, D N
1979-12-01
Medical ethicists debate whether or not the moral assessment of cases of euthanasia should depend on whether the patient is 'killed' or 'allowed to die'. The usual presupposition is that a clear distinction between killing and letting die can be drawn so that this substantive question is not begged. I contend that the categorisation of cases of instances of killing rather than as instances of letting die depends in part on a prior moral assessment of the case. Hence is it trivially rather than substantively true that the distinction has moral significance. But even if a morally neutral (ie non-question begging) distinction could be drawn, its application to the euthanasia controversy is problematic. I illustrate the difficulties of employing this distinction to reach moral conclusions by critically discussing Philippa Foot's recent treatment of euthanasia. I conclude that even if an act of euthanasia is an instance of killing, and there exists a prima facie moral duty not to kill, and no more stringent duty overrides this duty, one still cannot determine such an act to be morally impermissible.
DEFF Research Database (Denmark)
Fausing, Bent
Images can provide both an overview and insight, but also the opposite. This ambivalence has become an even bigger part of the nature of the image, of what is an Image? Today we kill for an image, seen from afar on a screen and captured by a drone. The time also asks: Should it be big data...
"The Killing Fields" of Innovation
DEFF Research Database (Denmark)
Ingerslev, Karen
2014-01-01
This paper points to seemingly contradicted processes of framing innovation, idea generation and killing ideas. It reports from a yearlong innovation project, where health care professionals explored problems and tested ideas for solutions, regarding a future downsizing of the case hospital...
Human Neutrophils Kill Bacillus anthracis.
Directory of Open Access Journals (Sweden)
2005-11-01
Full Text Available Bacillus anthracis spores cause natural infections and are used as biological weapons. Inhalation infection with B. anthracis, the etiological agent of anthrax, is almost always lethal, yet cutaneous infections usually remain localized and resolve spontaneously. Neutrophils are typically recruited to cutaneous but seldom to other forms of anthrax infections, raising the possibility that neutrophils kill B. anthracis. In this study we infected human neutrophils with either spores or vegetative bacteria of a wild-type strain, or strains, expressing only one of the two major virulence factors. The human neutrophils engulfed B. anthracis spores, which germinated intracellularly and were then efficiently killed. Interestingly, neutrophil killing was independent of reactive oxygen species production. We fractionated a human neutrophil granule extract by high-performance liquid chromatography and identified alpha-defensins as the component responsible for B. anthracis killing. These data suggest that the timely recruitment of neutrophils can control cutaneous infections and possibly other forms of B. anthracis infections, and that alpha-defensins play an important role in the potent anti-B. anthracis activity of neutrophils.
Human neutrophils kill Bacillus anthracis.
Directory of Open Access Journals (Sweden)
Anne Mayer-Scholl
2005-11-01
Full Text Available Bacillus anthracis spores cause natural infections and are used as biological weapons. Inhalation infection with B. anthracis, the etiological agent of anthrax, is almost always lethal, yet cutaneous infections usually remain localized and resolve spontaneously. Neutrophils are typically recruited to cutaneous but seldom to other forms of anthrax infections, raising the possibility that neutrophils kill B. anthracis. In this study we infected human neutrophils with either spores or vegetative bacteria of a wild-type strain, or strains, expressing only one of the two major virulence factors. The human neutrophils engulfed B. anthracis spores, which germinated intracellularly and were then efficiently killed. Interestingly, neutrophil killing was independent of reactive oxygen species production. We fractionated a human neutrophil granule extract by high-performance liquid chromatography and identified alpha-defensins as the component responsible for B. anthracis killing. These data suggest that the timely recruitment of neutrophils can control cutaneous infections and possibly other forms of B. anthracis infections, and that alpha-defensins play an important role in the potent anti-B. anthracis activity of neutrophils.
Human neutrophils kill Bacillus anthracis.
Mayer-Scholl, Anne; Hurwitz, Robert; Brinkmann, Volker; Schmid, Monika; Jungblut, Peter; Weinrauch, Yvette; Zychlinsky, Arturo
2005-11-01
Bacillus anthracis spores cause natural infections and are used as biological weapons. Inhalation infection with B. anthracis, the etiological agent of anthrax, is almost always lethal, yet cutaneous infections usually remain localized and resolve spontaneously. Neutrophils are typically recruited to cutaneous but seldom to other forms of anthrax infections, raising the possibility that neutrophils kill B. anthracis. In this study we infected human neutrophils with either spores or vegetative bacteria of a wild-type strain, or strains, expressing only one of the two major virulence factors. The human neutrophils engulfed B. anthracis spores, which germinated intracellularly and were then efficiently killed. Interestingly, neutrophil killing was independent of reactive oxygen species production. We fractionated a human neutrophil granule extract by high-performance liquid chromatography and identified alpha-defensins as the component responsible for B. anthracis killing. These data suggest that the timely recruitment of neutrophils can control cutaneous infections and possibly other forms of B. anthracis infections, and that alpha-defensins play an important role in the potent anti-B. anthracis activity of neutrophils.
Directory of Open Access Journals (Sweden)
Jenna Kathryn Ballinger
2014-09-01
Full Text Available I use the Teen Wolf fandom as an example to examine the ways social media has created a more complicated, nuanced relationship with fans. The collapse of the fourth wall between fans and The Powers That Be can have both positive and negative impacts, depending on the willingness of participants to maintain mutual respect and engage in meaningful dialogue.
Institute of Scientific and Technical Information of China (English)
高永馨; 谢燕华
2012-01-01
利用上下解方法,讨论了四阶微分方程非线性两点边值问题y(4) =f(x,y,y′,y″,y(′″)),y(b) =b0,y′(b) =b1,y″(b) =h(y″(a)),g(y(a),y(b),y′(a),y′(b),y″(a),y″(b),y(′″)(a),y(′″)(b)) =0解的存在唯一性.%By using the method of upper - lower solution,the existence and uniquenss of solutions of nonlinear two -point boundary value problems for fourth order differential equation y(4) =f(x,y,y′,y″,y(′″)),y(b) =b0,y′(b) =b1,y″(b) =h(y″(a)),g(y(a),y(b),y′(a),y′(b),y″(a),y″(b),y(′″)(a),y(′″)(b)) =0 are investigated.
WOMEN'S RIGHTS VIOLATION: HONOUR KILLINGS
Directory of Open Access Journals (Sweden)
CRISTINA OTOVESCU FRASIE
2011-04-01
Full Text Available In this study I have presented the domestic violence concept and the situation regarding the observing of woman’s rights in Syria. We have also evidenced the juridical aspects regarding the honor killing directed against women after the modification of the article 548 from the Penal Code changed by the President al-Asad on July the 1st 2009. The data offered by NGOs have been of great help for the elaboration of the study as also the statistic data presented in Thara E-Magazine regarding the cities where had been done the honor killings and their number, the instrument of the murder, the age of the victim, and the motives for the murders. It must be noticed that, lately, the Government fought for the observing of the woman’s rights and promoted he gender equality by appointing women in leading positions, including the vice-president one.
f(R)-gravity from Killing tensors
Paliathanasis, Andronikos
2016-04-01
We consider f(R)-gravity in a Friedmann-Lemaître-Robertson-Walker spacetime with zero spatial curvature. We apply the Killing tensors of the minisuperspace in order to specify the functional form of f(R) and for the field equations to be invariant under Lie-Bäcklund transformations, which are linear in momentum (contact symmetries). Consequently, the field equations to admit quadratic conservation laws given by Noether’s theorem. We find three new integrable f(R)-models, for which, with the application of the conservation laws, we reduce the field equations to a system of two first-order ordinary differential equations. For each model we study the evolution of the cosmological fluid. We find that for each integrable model the cosmological fluid has an equation of state parameter, in which there is linear behavior in terms of the scale factor which describes the Chevallier, Polarski and Linder parametric dark energy model.
Fourth-generation storage rings
Energy Technology Data Exchange (ETDEWEB)
Galayda, J. N.
1999-11-16
It seems clear that a linac-driven free-electron laser is the accepted prototype of a fourth-generation facility. This raises two questions: can a storage ring-based light source join the fourth generation? Has the storage ring evolved to its highest level of performance as a synchrotrons light source? The answer to the second question is clearly no. The author thinks the answer to the first question is unimportant. While the concept of generations has been useful in motivating thought and effort towards new light source concepts, the variety of light sources and their performance characteristics can no longer be usefully summed up by assignment of a ''generation'' number.
The fourth generation in supergravity
Enqvist, K.; Nanopoulos, D. V.; Zwirner, F.
1985-12-01
We consider model-independent constraints on the fourth-generation fermion masses and the magnitude of the D-term contribution to the scalar masses. We find that the ratio of vacuum expectation values is limited to the range 1/5 ~ 150 GeV. A general feature of the four-generation models is thus a heavy spectrum of sparticles. On leave from International School for Advanced Studies, Trieste, and Istituto Nazionale di Fisica Nucleare, Padua, Italy.
Directory of Open Access Journals (Sweden)
Vesa Iitti
2008-01-01
Full Text Available This article focuses on the general history of the Fourth Way in Finland. The Fourth Way, or simply ‘the Work’, began as a Greco-Armenian man named Georges Ivanovich Gurdjieff (1866?–1949 gathered groups of pupils in St Petersburg and Moscow in 1912. To these groups, Gurdjieff started to teach what he had learned and synthesized between ca 1896 and 1912 during his travels on spiritual search of Egypt, Crete, Sumeria, Assyria, the Holy Land, Mecca, Ethiopia, Sudan, India, Afghanistan, the northern valleys of Siberia, and Tibet. Neither Gurdjieff nor any of his disciples called themselves a church, a sect, or anything alike, but referred to themselves simply as ‘the Work’, or as ‘the Fourth Way’. The name ‘the Fourth Way’ originates in a Gurdjieffian view that there are essentially three traditional ways of spiritual work: those of a monk, a fakir, and a yogi. These ways do not literally refer to the activities of a monk, a fakir, and a yogi, but to similar types of spiritual work emphasizing exercise of emotion, body, or mind. Gurdjieff’s teaching is a blend of various influences that include Sufism, orthodox Christianity, Buddhism, Kabbalah, and general elements of various occult teachings of both the East and the West. Gurdjieff’s teaching is a blend of various influences that include Sufism, orthodox Christianity, Buddhism, Kabbalah, and general elements of various occult teachings of both the East and the West. It is a unique combination of cosmology, psychology, theory of evolution, and overall theory and practise aiming to help individuals in their efforts towards what is called ‘self-remembering’.
Fourth order accurate compact scheme with group velocity control (GVC)
Institute of Scientific and Technical Information of China (English)
MA; Yanwen
2001-01-01
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Ultimate storage ring based on fourth-order geometric achromats
Directory of Open Access Journals (Sweden)
Yunhai Cai
2012-05-01
Full Text Available We have designed an “ultimate” storage ring for a future light source that would be resided in the positron-electron-project (PEP tunnel and achieves the diffraction-limited emittances (at 1.5 Å of 12 pm-rad in both horizontal and vertical planes with a 4.5-GeV electron beam. These emittances include the contribution of intrabeam scattering at a nominal current of 200 mA in 3300 bunches. This quality beam in conjunction with a conventional 4-m undulator in a straight section can generate synchrotron radiation having a spectral brightness above 10^{22} [photons/s/mm^{2}/mrad^{2}/0.1%BW] at a 10 keV photon energy. The high coherence at the diffraction limit makes this design competitive with 4th generation light sources based on an energy recovery linac. In addition, the beam lifetime is several hours and the dynamic aperture is large enough to allow off-axis injection. The alignment and stability tolerances, though challenging, are achievable. A ring with all these properties is only possible because of several major advances in mitigating the effects of nonlinear resonances.
Benthic macroinvertebrate community of a fourth order stream in ...
African Journals Online (AJOL)
cinthia
Jehlum. The sampling sites (Figure 1) were located in the stream ... Highest relative density (94.5%) was recorded for phylum. Arthropoda. .... Mathematical theory of ... Tolkamp HH (1980). organic-substrate relationship in low land streams.
Killing for Girls: Predation Play and Female Empowerment
Bertozzi, Elena
2012-01-01
Predation games--games in which the player is actively encouraged and often required to hunt and kill in order to survive--have historically been the purview of male players. Females, though now much more involved in digital games than before, generally play games that stress traditionally feminine values such as socializing with others, shopping,…
Killing for Girls: Predation Play and Female Empowerment
Bertozzi, Elena
2012-01-01
Predation games--games in which the player is actively encouraged and often required to hunt and kill in order to survive--have historically been the purview of male players. Females, though now much more involved in digital games than before, generally play games that stress traditionally feminine values such as socializing with others, shopping,…
Women who kill their children.
Rougé-Maillart, Clotilde; Jousset, Nathalie; Gaudin, Arnaud; Bouju, Brigitte; Penneau, Michel
2005-12-01
The killing of a newborn on the day of its birth is known as neonaticide. A child aged 1 through 16 has a different role in the family, and their murder is perceived differently. We would expect mothers charged with filicide to be drawn from a slightly different population than other child-killing mothers. Our study was carried out at the Institute of Forensic Medicine in Angers over a 10-year period. All the victims were autopsied at the Institute of Forensic Medicine in Angers. Information concerning the mothers was collected from forensic medical files, police reports, and legal files. Interviews and forensic psychiatric examinations were available for consultation. Our study concerns 17 observations of child-killing mothers and 19 child autopsies. In 2 cases, the issue was in fact a double murder, with the mother killing all the siblings. The mean age was 3.5 years for victims and 29.5 years for the women. The majority of the mothers were married or lived with their partners. They often had an occupation. Generally the economic status was average. Head trauma, strangulation, suffocation, and drowning were the most frequent means of filicide. However, some mothers used more active methods such as striking and shooting. Disturbed or disturbing behavior was documented in 15 perpetrators. Seven women tried to commit suicide. It was often possible to identify apparent motivation for the offense. In our study, we can distinguish 2 types of killer mothers. We distinguished a first group made up of 5 mothers. These 5 women killed their children in a general context of abused children and present similarities with the neonaticide mothers (young, immature). The other group of filicide mothers is different. They are generally older, married, and employed. The crime is usually premeditated, committed with the direct use of hands and sometimes very violent. To understand the motives or the source of the impulse to kill, we can use a classification such as Resnick
Killing(-Yano) Tensors in String Theory
Chervonyi, Yuri
2015-01-01
We construct the Killing(-Yano) tensors for a large class of charged black holes in higher dimensions and study general properties of such tensors, in particular, their behavior under string dualities. Killing(-Yano) tensors encode the symmetries beyond isometries, which lead to insights into dynamics of particles and fields on a given geometry by providing a set of conserved quantities. By analyzing the eigenvalues of the Killing tensor, we provide a prescription for constructing several conserved quantities starting from a single object, and we demonstrate that Killing tensors in higher dimensions are always associated with ellipsoidal coordinates. We also determine the transformations of the Killing(-Yano) tensors under string dualities, and find the unique modification of the Killing-Yano equation consistent with these symmetries. These results are used to construct the explicit form of the Killing(-Yano) tensors for the Myers-Perry black hole in arbitrary number of dimensions and for its charged version.
Haisch, Ulrich
2007-01-01
Within constrained minimal-flavor-violation the large destructive flavor-changing Z-penguin managed to survive eradication so far. We give a incisive description of how to kill it using the precision measurements of the Z -> b anti-b pseudo observables. The derived stringent range for the non-standard contribution to the universal Inami-Lim function C leads to tight two-sided limits for the branching ratios of all Z-penguin dominated flavor-changing K- and B-decays.
Energy Technology Data Exchange (ETDEWEB)
1980-04-01
More than nine months after it erupted 6/3/79, Petroleos Mexicanos' Ixtoc 1 blowout in Campeche Bay was killed with three cement plugs having a total length of 2885 ft. After drilling of relief wells, 200 sacks of cement were used to form the 685 ft. long bottom plug. After inserting an interval of mud, an additional 200 sacks of cement were pumped down to form a 550 ft. plug. The final up-hole plug was formed by 500 sacks of quick-setting cement, which formed a 1650 ft. long plug.
The fourth dimension simply explained
Manning, Henry P
2005-01-01
To remove the contents of an egg without puncturing its shell or to drink the liquor in a bottle without removing the cork is clearly unthinkable - or is it? Understanding the world of Einstein and curved space requires a logical conception of the fourth dimension.This readable, informative volume provides an excellent introduction to that world, with 22 essays that employ a minimum of mathematics. Originally written for a contest sponsored by Scientific American, these essays are so well reasoned and lucidly written that they were judged to merit publication in book form. Their easily unders
Letting die and mercy killing.
Narbekovas, Andrius; Meilius, Kazimieras
2003-01-01
We are all called to make moral decisions, not only about preserving life and health, but also about accepting our death and dying. There are situations, when it is morally right, and indeed obligatory, to allow a dying person to die in peace and dignity. But there is a world of difference between allowing a peaceful death, and deliberately setting out to bring death of the person either by acts of commission (s.c. 'active euthanasia'), or by acts of omission (s.c. 'passive euthanasia'). The word "killing" seems proper for euthanasia, because "to kill" does mean " to intentionally cause the death of someone." It can be morally acceptable to withhold or withdraw a treatment precisely because it is reasonably judged as inefficacious (futile), or excessively burdensome for the patient. One's reason for withholding such treatment must not be a judgement about the desirability of putting an end to the patient's life, but a judgement about the desirability of putting an end to the treatment, which is futile or burdensome.
Towards Reviving Electroweak Baryogenesis with a Fourth Generation
Directory of Open Access Journals (Sweden)
Wei-Shu Hou
2013-01-01
universe. However, it does not work within the standard model due to two reasons: (1 the strength of CP violation from the Kobayashi-Maskawa mechanism with three generations is too small; (2 the electroweak phase transition is not first order for the experimentally allowed Higgs boson mass. We discuss possibilities to solve these problems by introducing a fourth generation of fermions and how electroweak baryogenesis might be revived. We also discuss briefly the recent observation of a Higgs-like boson with mass around 125 GeV, which puts the fourth generation in a difficult situation, and the possible way out.
Directory of Open Access Journals (Sweden)
K.S. Seshadri
2009-11-01
Full Text Available A survey of amphibian mortality on roads was carried out in the Sharavathi river basin in the central Western Ghats. Road kills in three different land use areas: agricultural fields, water bodies and forests were recorded for four days along three 100m stretches in each type of area. One-hundred-and-forty-four individuals belonging to two orders, eight families, 11 genera and 13 species were recorded in the survey. Kills/km observed were: in forest 55, agricultural fields 38 and water bodies 27, for an overall average of 40 kills/km. Kill species compositions varied significantly between land use areas, but not overall kill rates.
Dark Coulomb binding of heavy neutrinos of fourth family
Belotsky, K. M.; Esipova, E. A.; Khlopov, M. Yu.; Laletin, M. N.
2015-11-01
Direct dark matter searches put severe constraints on the weakly interacting massive particles (WIMPs). These constraints cause serious troubles for the model of stable neutrino of fourth generation with mass around 50GeV. Though the calculations of primordial abundance of these particles make them in the charge symmetric case a sparse subdominant component of the modern dark matter, their presence in the universe would exceed the current upper limits by several orders of the magnitude. However, if quarks and leptons of fourth generation possess their own Coulomb-like y-interaction, recombination of pairs of heavy neutrinos and antineutrinos and their annihilation in the “neutrinium” atoms can play important role in their cosmological evolution, reducing their modern abundance far below the experimental upper limits. The model of stable fourth generation assumes that the dominant part of dark matter is explained by excessive Ū antiquarks, forming (ŪŪŪ)-- charged clusters, bound with primordial helium in nuclear-interacting O-helium (OHe) dark atoms. The y charge conservation implies generation of the same excess of fourth generation neutrinos, potentially dangerous WIMP component of this scenario. We show that due to y-interaction recombination of fourth neutrinos with OHe hides these WIMPs from direct WIMP searches, leaving the negligible fraction of free neutrinos, what makes their existence compatible with the experimental constraints.
Cryptococcus Neoformans Modulates Extracellular Killing by Neutrophils
Qureshi, Asfia; Grey, Angus; Rose, Kristie L; Schey, Kevin L.; Del Poeta, Maurizio
2011-01-01
We recently established a key role for host sphingomyelin synthase (SMS) in regulating the killing activity of neutrophils against Cryptococcus neoformans. In this paper, we studied the effect of C. neoformans on the killing activity of neutrophils and whether SMS would still be a player against C. neoformans in immunocompromised mice lacking T and natural killer (NK) cells (Tgε26 mice). To this end, we analyzed whether C. neoformans would have any effect on neutrophil survival and killing in...
Fourth Lepton Family is Natural in Technicolor
DEFF Research Database (Denmark)
T. Frandsen, Mads; Masina, Isabella; Sannino, Francesco
2010-01-01
structure with and without mixing with the Standard Model families. We also analyze the LHC potential to observe the fourth lepton family in tandem with the new composite Higgs dynamics. We finally introduce a model uniting the fourth lepton family and the technifermion sector at higher energies.......Imagine to discover a new fourth family of leptons at the Large Hadron Collider (LHC) but no signs of an associated fourth family of quarks. What would that imply? An intriguing possibility is that the new fermions needed to compensate for the new leptons gauge anomalies simultaneously address...
f(R)-gravity from Killing Tensors
Paliathanasis, Andronikos
2015-01-01
We consider $f\\left( R\\right) $-gravity in a Friedmann-Lema\\^{\\i}tre-Robertson-Walker spacetime with zero spatial curvature. We apply the Killing tensors of the minisuperspace in order to specify the functional form of $f\\left( R\\right) $ and the field equations to be invariant under Lie-B\\"{a}cklund transformations which are linear in the momentum (contact symmetries). Consequently, the field equations to admit quadratic conservation laws given by Noether's Theorem. We find three new integrable $f\\left( R\\right) $ models, for which with the application of the conservation laws we reduce the field equations to a system of two first-order ordinary differential equations. For each model we study the evolution of the cosmological fluid. Where we find that for the one integrable model the cosmological fluid has an equation of state parameter, in which in the latter there is a linear behavior in terms of the scale factor which describes the CPL parametric dark energy model.
Killing and letting die: a defensible distinction.
Cartwright, W
1996-04-01
The distinction between killing and letting die is investigated and clarified. It is then argued that in most cases, though not in all, it is worse to kill than to let die. In euthanasia the significance of the distinction is diminished, but still important.
Puzzling cases about killing and letting die.
Favor, C D
1996-01-01
Discussions of euthanasia often appeal to the distinction between killing people and letting them die. Favor asks whether this distinction is morally important--in particular, whether killing is worse than merely letting someone die, even when the motivations and consequences are the same. She explores our moral intuitions via a discussion of various subtly different hypothetical examples.
The Killing Forms of Lie Triple Systems
Institute of Scientific and Technical Information of China (English)
ZHANG Zhi Xue; GAO Rui
2009-01-01
For Lie triple systems in the characteristic zero setting, we obtain by means of the Killing forms two criterions for semisimplicity and for solvability respectively, and then investigate the relationship among the Killing forms of a real Lie triple system To, the complexification T of To, and the realification of T.
Karo-kari: a form of honour killing in pakistan.
Patel, Sujay; Gadit, Amin Muhammad
2008-12-01
Karo-Kari is a type of premeditated honour killing, which originated in rural and tribal areas of Sindh, Pakistan. The homicidal acts are primarily committed against women who are thought to have brought dishonour to their family by engaging in illicit pre-marital or extra-marital relations. In order to restore this honour, a male family member must kill the female in question. We conducted a systematic review of the published literature other sources on karo-kari and related forms of honour killing or violence against women. Media and non-governmental organization reports were utilized for case studies and analysis. Although legally proscribed, socio-cultural factors and gender role expectations have given legitimacy to karo-kari within some tribal communities. In addition to its persistence in areas of Pakistan, there is evidence that karo-kari may be increasing in incidence in other parts of the world in association with migration. Moreover, perpetrators of ;honour killings' often have motives outside of female adultery. Analysis of the socio-cultural and psycho-pathological factors associated with the practice of karo-kari can guide the development of prevention strategies.
Killing, letting die, and simple conflicts.
Malm, H M
1989-01-01
Proponents of the moral equivalence of killing and letting die argue that in cases of simple conflict, where one agent must either perform a positive act and kill one person, or not perform that act and allow another person to die, the agent's alternatives are clearly morally equivalent. Malm rejects this view in a three part essay. He argues that in cases of simple conflict, the acts of killing and letting die are morally different, and that killing is not in itself worse than letting die. Malm considers and rejects the suggestion that the agent should decide randomly between the two alternatives. He concludes that while simple conflict cases require us to recognize a morally significant difference between killing and letting die, they do not require us to recognize a morally significant difference between acting and refraining.
Killing cells by targeting mitosis.
Manchado, E; Guillamot, M; Malumbres, M
2012-03-01
Cell cycle deregulation is a common feature of human cancer. Tumor cells accumulate mutations that result in unscheduled proliferation, genomic instability and chromosomal instability. Several therapeutic strategies have been proposed for targeting the cell division cycle in cancer. Whereas inhibiting the initial phases of the cell cycle is likely to generate viable quiescent cells, targeting mitosis offers several possibilities for killing cancer cells. Microtubule poisons have proved efficacy in the clinic against a broad range of malignancies, and novel targeted strategies are now evaluating the inhibition of critical activities, such as cyclin-dependent kinase 1, Aurora or Polo kinases or spindle kinesins. Abrogation of the mitotic checkpoint or targeting the energetic or proteotoxic stress of aneuploid or chromosomally instable cells may also provide further benefits by inducing lethal levels of instability. Although cancer cells may display different responses to these treatments, recent data suggest that targeting mitotic exit by inhibiting the anaphase-promoting complex generates metaphase cells that invariably die in mitosis. As the efficacy of cell-cycle targeting approaches has been limited so far, further understanding of the molecular pathways modulating mitotic cell death will be required to move forward these new proposals to the clinic.
Antibacterial surface design - Contact kill
Kaur, Rajbir; Liu, Song
2016-08-01
Designing antibacterial surfaces has become extremely important to minimize Healthcare Associated Infections which are a major cause of mortality worldwide. A previous biocide-releasing approach is based on leaching of encapsulated biocides such as silver and triclosan which exerts negative impacts on the environment and potentially contributes to the development of bacterial resistance. This drawback of leachable compounds led to the shift of interest towards a more sustainable and environmentally friendly approach: contact-killing surfaces. Biocides that can be bound onto surfaces to give the substrates contact-active antibacterial activity include quaternary ammonium compounds (QACs), quaternary phosphoniums (QPs), carbon nanotubes, antibacterial peptides, and N-chloramines. Among the above, QACs and N-chloramines are the most researched contact-active biocides. We review the engineering of contact-active surfaces using QACs or N-chloramines, the modes of actions as well as the test methods. The charge-density threshold of cationic surfaces for desired antibacterial efficacy and attempts to combine various biocides for the generation of new contact-active surfaces are discussed in detail. Surface positive charge density is identified as a key parameter to define antibacterial efficacy. We expect that this research field will continue to attract more research interest in view of the potential impact of self-disinfective surfaces on healthcare-associated infections, food safety and corrosion/fouling resistance required on industrial surfaces such as oil pipes and ship hulls.
Institute of Scientific and Technical Information of China (English)
张芳; 桂志国; 张权; 董婵婵
2016-01-01
In low-dose CT (computed tomography)reconstruction algorithm,traditional maximum likelihood expectation maximisation (MLEM)algorithm will appear chessboard effect along with the increase of the number of iterations,thus cannot effectively suppress noises. For this problem,this paper proposes a low dose CT reconstruction algorithm,which is based on the combination of wavelet shrinkage and fourth-order anisotropic diffusion.It combines the advantages of wavelet shrinkage and anisotropic diffusion,in each iteration,it conducts the discrete stationary wavelet decomposition on the image processed with MLEM reconstruction algorithm,in high frequency part of the wavelet domain it shrinks the wavelet,in low frequency part it uses fourth-order anisotropic diffusion,which has high quality effect in denoising,to eliminate noises,it processes the final residual pulse noise points with the median filter,so that further optimises the image.Simulation experiment results show that the proposed algorithm can effectively remove the noise in low-dose CT image,and has good performances in keeping both the image edges and detailed information,thereby gains the image with high anti-noise performance.%在低剂量计算机断层扫描 CT（computed tomography）重建算法中，传统的最大似然期望最大 MLEM（Maximum Likelihood Expectation Maximization）算法随着迭代次数的增加会出现棋盘效应而不能有效地抑制噪声。针对上述问题提出一种基于小波收缩和四阶各向异性扩散相结合的 MLEM低剂量 CT 重建算法。该算法结合小波收缩和各向异性扩散的优点，在每次迭代中，对 MLEM重建算法处理后的图像进行离散平稳小波分解，在小波域的高频部分进行小波收缩，低频部分使用降噪效果优质的四阶各向异性扩散进行消噪，最后残留的脉冲噪声点通过中值滤波器进行处理，从而进一步优化图像。仿真实验结果表明，该算法
Institute of Scientific and Technical Information of China (English)
徐元欣; 王安国; 聂仲尔
2011-01-01
该文提出了一种新的基于四阶累积量的信源多参数联合估计方法,可实现信源频率、方位及距离的联合估计.该算法无需峰值搜索,适用于任意高斯噪声环境,可有效降低阵列孔径损失.算法中,通过选取特定序号阵元上的输出构造四阶累积量矩阵,有效地避免了因同时存在远场源时而出现的矩阵降秩现象,因而该算法适用于近场、远场或混合信源的参数估计.仿真结果验证了提出方法的有效性.%A new algorithm for jointly estimating multi-parameters (the frequency, Direction Of Arrival (DOA) and range) of sources is proposed. The proposed algorithm does not require spectral peak search, and can be applied to arbitrary Gaussian noise environment. It can reduce the aperture loss. Moreover, the fourth order cumulant matrices are constructed using the special sensor outputs, and the rank reduction of matrices can be avoided when the far-field sources impinging on an array of sensors. So the proposed algorithm can be used to estimate the parameters of near-field, far-field and mixed sources. The performance of the proposed method is validated by simulations.
Institute of Scientific and Technical Information of China (English)
巩文迪; 刘佳毅; 卢兆林
2013-01-01
The final monitoring images in video monitoring system are usually in low contrast and brightness because of special application environment in underground mine. A improved denoising method based fourth-order Partial Differential Equations (PDE) is proposed in this paper. The proposed method segments the image domain into speckle domain and non-speckle domain, then uses different conductance coefficients depending on the domain type. Comparing to traditional anisotropic diffusion method, the simulation results show that this method will suppress the noise so as to achieve a better image quality and visual effect. At the same time, it can effectively remove isolated speckles, eliminates flash point ,keeps edge details and line texture in the image.%煤矿井下特殊的应用环境直接影响着图像的质量，导致图像视觉效果较差。文章提出一种改进的基于四阶PDE的去噪方法，该方法将图像区域分为闪点区域和非闪点区域，并针对不同的区域采用不同的传导系数。与传统的各向异性扩散方法相比较，仿真实验结果表明，该方法在抑制噪声的同时能够有效克服二阶偏微分方程引起的块效应、消除闪点并保持图像的边缘、线条纹理等细节，从而达到更好的图像质量和视觉效果。
United States housing, fourth quarter 2013
Delton Alderman
2017-01-01
In the beginning of 2013, the U.S. housing construction market indicated increases in all sectors; yet, by the fourth quarterâs end, only housing under construction improved. Moderation and declines are to be expected in the fourth quarter, as winter is setting in. Permits, starts, housing under construction, completions, and new and existing house sales all exceeded...
Osteoblastic meningioma of the fourth ventricle.
Johnson, M D; Tulipan, N; Whetsell, W O
1989-04-01
Meningiomas of the fourth ventricle are rare neoplasms. Only meningothelial and fibroblastic subtypes, purportedly arising from the tela choroidea, have been described. In this report we describe clinical, neuroradiological and pathological findings in a 52-year-old man with mild hydrocephalus produced by a large, calcified, osteoblastic meningioma of the fourth ventricle.
Credito, K L; Ednie, L M; Jacobs, M R; Appelbaum, P C
1999-08-01
Time-kill studies examined the activities of telithromycin (HMR 3647), erythromycin A, azithromycin, clarithromycin, roxithromycin, clindamycin, pristinamycin, amoxicillin-clavulanate, and metronidazole against 11 gram-positive and gram-negative anaerobic bacteria. Time-kill studies were carried out with the addition of Oxyrase in order to prevent the introduction of CO(2). Macrolide-azalide-ketolide MICs were 0.004 to 32.0 microg/ml. Of the latter group, telithromycin had the lowest MICs, especially against non-Bacteroides fragilis group strains, followed by azithromycin, clarithromycin, erythromycin A, and roxithromycin. Clindamycin was active (MIC /=99.9% killing) against 6 strains, with 99% killing of 9 strains and 90% killing of 10 strains. After 24 h at twice the MIC, 90, 99, and 99.9% killing of nine, six, and three strains, respectively, occurred. Lower rates of killing were seen at earlier times. Similar kill kinetics relative to the MIC were seen with other macrolides. After 48 h at the MIC, clindamycin was bactericidal against 8 strains, with 99 and 90% killing of 9 and 10 strains, respectively. After 24 h, 90% killing of 10 strains occurred at the MIC. The kinetics of clindamycin were similar to those of pristinamycin. After 48 h at the MIC, amoxicillin-clavulanate showed 99.9% killing of seven strains, with 99% killing of eight strains and 90% killing of nine strains. At four times the MIC, metronidazole was bactericidal against 8 of 10 strains tested after 48 h and against all 10 strains after 24 h; after 12 h, 99% killing of all 10 strains occurred.
Fungal and bacterial killing by neutrophils.
Ermert, David; Zychlinsky, Arturo; Urban, Constantin
2009-01-01
Neutrophils are professional phagocytes of the innate immune system that are essential to control bacterial and fungal infections. These cells engulf and kill invading microbes. Additionally, activated neutrophils are able to release neutrophil extracellular traps (NETs). These fibers consist of chromatin decorated with antimicrobial proteins to trap and kill microbes. Appropriate quantitative methods are required to understand the nature of interactions of neutrophils with pathogens. Here we present assays to measure killing mediated by phagocytosis, by NETs, by a combination of both, and by granular extract. As examples, we use Candida albicans for fungal and Shigella flexneri for bacterial pathogens.
Contagion in Mass Killings and School Shootings
National Research Council Canada - National Science Library
Towers, Sherry; Gomez-Lievano, Andres; Khan, Maryam; Mubayi, Anuj; Castillo-Chavez, Carlos
2015-01-01
... the seeds of ideation in at-risk individuals to commit similar acts. Here we explore whether or not contagion is evident in more high-profile incidents, such as school shootings and mass killings...
Homefucking is Killing Prostitution / Taavi Eelmaa
Eelmaa, Taavi, 1971-
2008-01-01
Mis jääb vaatajale teatrietendusest meelde? Ilmus Kris Moori raamat "Homefucking is Killing Prostitution". Raamat sisaldab tekste ja Erki Lauri fotosid Von Krahli Teatri samanimelisest etendusest, mida kordagi ei mängitud
Killing superalgebras for Lorentzian four-manifolds
de Medeiros, Paul; Santi, Andrea
2016-01-01
We determine the Killing superalgebras underpinning field theories with rigid unextended supersymmetry on Lorentzian four-manifolds by re-interpreting them as filtered deformations of $\\mathbb{Z}$-graded subalgebras with maximum odd dimension of the $N{=}1$ Poincar\\'e superalgebra in four dimensions. Part of this calculation involves computing a Spencer cohomology group which, by analogy with a similar result in eleven dimensions, prescribes a notion of Killing spinor, which we identify with the defining condition for bosonic supersymmetric backgrounds of minimal off-shell supergravity in four dimensions. We prove that such Killing spinors always generate a Lie superalgebra, and that this Lie superalgebra is a filtered deformation of a subalgebra of the $N{=}1$ Poincar\\'e superalgebra in four dimensions. Demanding the flatness of the connection defining the Killing spinors, we obtain equations satisfied by the maximally supersymmetric backgrounds. We solve these equations, arriving at the classification of ma...
Acts and omissions, killing and letting die.
Gillon, R
1986-01-11
Gillon asks what, if any, moral importance resides in the distinction between killing and letting die in the context of medical care. He considers and rejects the acts and omissions doctrine, which claims that actions (killing) resulting in some undesirable end are in general morally worse than failures to act (allowing to die) that have the same result. He also refutes the argument that the moral distinction between killing and letting die is one of harming versus benefitting, and that a physician has a responsibility not to harm (kill) a patient but no duty to help (keep alive). Gillon concludes by discussing the moral claims upon which the Roman Catholic rejection of the acts and omissions doctrine is based, which are the subjects of his next British Medical Journal article on medical ethics.
Homefucking is Killing Prostitution / Taavi Eelmaa
Eelmaa, Taavi, 1971-
2008-01-01
Mis jääb vaatajale teatrietendusest meelde? Ilmus Kris Moori raamat "Homefucking is Killing Prostitution". Raamat sisaldab tekste ja Erki Lauri fotosid Von Krahli Teatri samanimelisest etendusest, mida kordagi ei mängitud
Killing vector fields and harmonic superfield theories
Energy Technology Data Exchange (ETDEWEB)
Groeger, Josua, E-mail: groegerj@mathematik.hu-berlin.de [Humboldt-Universität zu Berlin, Institut für Mathematik, Rudower Chaussee 25, 12489 Berlin (Germany)
2014-09-15
The harmonic action functional allows a natural generalisation to semi-Riemannian supergeometry, also referred to as harmonic, which resembles the supersymmetric sigma models studied in high energy physics. We show that Killing vector fields are infinitesimal supersymmetries of this harmonic action and prove three different Noether theorems in this context. En passant, we provide a homogeneous treatment of five characterisations of Killing vector fields on semi-Riemannian supermanifolds, thus filling a gap in the literature.
Killing Vector Fields and Superharmonic Field Theories
Groeger, Josua
2013-01-01
The harmonic action functional allows a natural generalisation to semi-Riemannian supergeometry, referred to as superharmonic action, which resembles the supersymmetric sigma models studied in high energy physics. We show that Killing vector fields are infinitesimal supersymmetries of the superharmonic action and prove three different Noether theorems in this context. En passant, we provide a homogeneous treatment of five characterisations of Killing vector fields on semi-Riemannian supermanifolds, thus filling a gap in the literature.
Is killing no worse than letting die?
Nesbitt, W
1995-01-01
Those who wish to refute the view that it is worse to kill than to let die sometimes produce examples of cases in which an agent lets someone die but would be generally agreed to be no less reprehensible than if he had killed. It is argued that the examples produced typically possess a feature which makes their use in this context illegitimate, and that when modified to remove this feature, they provide support for the view which they were designed to undermine.
Killing and letting die: hidden value assumptions.
Atkinson, G
1983-01-01
In this paper I argue for several related theses: first, that the distinction between killing and letting die, as it is drawn by ordinary persons in ordinary contexts, is more complex than is generally understood; second, that the key feature of this complexity lies in the presence of a hidden normative component in what appears to be a straightforwardly descriptive distinction; and, third, that this complexity renders the killing/letting die distinction an inadequate and hazardous guide for moral reasoning.
Cell killing by avian leukosis viruses.
Weller, S K; Temin, H M
1981-01-01
Infection of chicken cells with a cytopathic avian leukosis virus resulted in the detachment of killed cells from the culture dish. The detached, dead cells contained more unintegrated viral DNA than the attached cells. These results confirm the hypothesis that cell killing after infection with a cytopathic avian leukosis virus is associated with accumulation of large amounts of unintegrated viral DNA. No accumulation of large amounts of integrated viral DNA was found in cells infected with c...
Cryptococcus neoformans modulates extracellular killing by neutrophils.
Qureshi, Asfia; Grey, Angus; Rose, Kristie L; Schey, Kevin L; Del Poeta, Maurizio
2011-01-01
We recently established a key role for host sphingomyelin synthase (SMS) in regulating the killing activity of neutrophils against Cryptococcus neoformans. In this paper, we studied the effect of C. neoformans on the killing activity of neutrophils and whether SMS would still be a player against C. neoformans in immunocompromised mice lacking T and natural killer (NK) cells (Tgε26 mice). To this end, we analyzed whether C. neoformans would have any effect on neutrophil survival and killing in vitro and in vivo. We show that unlike Candida albicans, neither the presence nor the capsule size of C. neoformans cells have any effect on neutrophil viability. Interestingly, melanized C. neoformans cells totally abrogated the killing activity of neutrophils. We monitored how exposure of neutrophils to C. neoformans cells would interfere with any further killing activity of the conditioned medium and found that pre-incubation with live but not "heat-killed" fungal cells significantly inhibits further killing activity of the medium. We then studied whether activation of SMS at the site of C. neoformans infection is dependent on T and NK cells. Using matrix-assisted laser desorption-ionization tissue imaging in infected lung we found that similar to previous observations in the isogenic wild-type CBA/J mice, SM 16:0 levels are significantly elevated at the site of infection in mice lacking T and NK cells, but only at early time points. This study highlights that C. neoformans may negatively regulate the killing activity of neutrophils and that SMS activation in neutrophils appears to be partially independent of T and/or NK cells.
Cryptococcus neoformans modulates extracellular killing by neutrophils
Directory of Open Access Journals (Sweden)
Asfia eQureshi
2011-09-01
Full Text Available We recently established a key role for host sphingomyelin synthase (SMS in the regulation of the killing activity of neutrophils against Cryptococcus neoformans. In this work, we studied the effect of C. neoformans on the killing activity of neutrophils and whether SMS would still be a player against C. neoformans in immunocompromised mice lacking T and NK cells (Tgε26 mice. To this end, we analyzed whether C. neoformans would have any effect on neutrophil survival and killing in vitro and in vivo. We show that unlike C. albicans, neither the presence nor the capsule size of C. neoformans cells have any effect on neutrophil viability. Interestingly, melanized C. neoformans cells totally abrogated the killing activity of neutrophils. Next, we monitored how exposure of neutrophils to C. neoformans cells would interfere with any further killing activity of the medium and found that pre-incubation with live but not heat-killed fungal cells significantly inhibits further killing activity of the medium. We next studied whether activation of SMS at the site of C. neoformans infection is dependent on T and NK cells. Using matrix-assisted laser desorption-ionization (MALDI tissue imaging in infected lung we found that similarly to previous observations in the isogenic wild type CBA/J mice, SM 16:0 levels are significantly elevated at the site of infection in mice lacking T and NK cells but only at early time points. This study highlights that C. neoformans may negatively regulate the killing activity of neutrophils and that SMS activation in neutrophils appears to be partially independent of T and/or NK cells.
Killing Forms of Isotropic Lie Algebras
Malagon, Audrey
2010-01-01
This paper presents a method for computing the Killing form of an isotropic Lie algebra defined over an arbitrary field based on the Killing form of a subalgebra containing its anisotropic kernel. This approach allows for streamlined formulas for many Lie algebras of types E6 and E7 and yields a unified formula for all Lie algebras of inner type E6, including the anisotropic ones.
Institute of Scientific and Technical Information of China (English)
杨如红; 邵振峰; 张磊
2014-01-01
采用非下采样 Contourlet 变换（NSCT）模型提出了基于四阶相关系数的红外与可见光图像融合方法。首先对融合图像进行多尺度和多方向分解；对于低频分量，充分考虑红外和可见光图像物理特性的差异，采用基于区域平均梯度的融合策略；对高频分量采用四阶相关系数匹配策略来选择合适的高频系数；最后对融合后的系数进行 NSCT 逆变换得到融合图像。实验结果表明，该融合算法能更好地保留目标信息，同时也显著地提高了图像的信息量，在主观视觉效果和客观评价方面具有较好的融合性能。%In this paper,a new method based on nonsubsampled contourlet transform (NSCT)is proposed to fuse the infrared image and the visible light image.Firstly,the NSCT is performed on the original images to obtain the sub-bands coefficient in different scales and various directions.Considering the physical characteristics of two original im-ages,fusion strategy based on the regional average gradient is used for the low frequency sub-band coefficients.For the high frequency sub-band coefficients,the fourth-order correlation coefficient match strategy is used to select the suitable high-frequency coefficients.Finally,the fused coefficients are reconstructed to obtain the fused image.The experiment results show that the proposed method performs better in keeping and improving the target information,and it has better fusion performance in subjective visual effect and objective evaluation.
Institute of Scientific and Technical Information of China (English)
冯德山; 杨道学; 王珣
2016-01-01
using fourth-order Runge-Kutta method (RK4) for calculating the higher time derivative. Compared with the conventional finite differ-ence time domain (FDTD) algorithm based on the central difference method, the interpolation wavelet scale algorithm improves the accuracy of GPR wave equation in both space and time discretization. Firstly, the FDTD algorithm and the interpolation wavelet scale method are applied to the forward modeling of a layered model with analytic solution. Single channel radar data and analytical solution fitting indicate that the interpolation wavelet scale method has higher accuracy than FDTD, with the same mesh generation used. Therefore, auxiliary differential equation perfectly matching layer (ADE-PML) boundary condition is used on an interpolation wavelet scale, and the comparisons between reflection errors obtained using CPML(FDTD), RK4ADE-PML(FDTD), and RK4ADE-PML(interpolating wavelet scales) in a homogeneous medium model show that the absorption effect of RK4ADE-PML(interpolating wavelet scales) is better than the other two absorbing boundaries. Finally, interpolation wavelet scale method, with both UPML, FDTD and RK4ADE-PML loaded, is used for two-dimensional GPR forward modeling, showing good absorption effect for evanescent wave. From all the experimental results, the following conclusions are obtained. 1) Using the derivative of the inter-polating wavelet scale function instead of central difference schemes for the spatial derivative discretization of Maxwell equations and time derivative calculated using the fourth-order Runge Kutta algorithm, the interpolating wavelet scale algorithm has higher accuracy than regular FDTD algorithm due to the improvement in the spatial and time accuracy of GPR wave equation. 2) The best absorption layer parameters of interpolating wavelet scale RK4ADE-PML are selected, when the maximum value of the reflection error is the minimum. The maximum reflection error can reach-93 dB, which increases 20 d
Animal protection from killing and abuse in the European and Serbian criminal law
Krstić, Novak
2012-01-01
In this paper, the author primarily deals with an issue of animal protection against unnecessary killing, torture and abuse in the EU law, with specific reference to the Serbian legislation on this issue. Many European countries have introduced into their criminal legislations some legal provisions defining the act of animal killing and abuse as a criminal offense. In order to observe the standards, forms and intensity of state response to men’s cruelty to animals, the author will analyze the...
The Fourth Wave in Deterrence Research
Knopf, Jeffrey W.
2010-01-01
The article of record as published may be located at http://dx.doi.org/10.1080/13523261003640819 A new line of work on deterrence began emerging after the end of the Cold War and gained momentum after the September 11 terrorist attacks. Building on a previous characterization by Robert Jervis that identified three waves of deterrence research,1 this work is here designated the fourth wave. The fourth wave reflects a change from a focus on relatively symmetrical situations of mu...
Can patriotism justify killing in defense of one’s country?
Directory of Open Access Journals (Sweden)
Pavković Aleksandar
2007-01-01
Full Text Available Cosmopolitan liberals would be ready to fight - and to kill and be killed for the sake of restoring international justice or for the abolition of profoundly unjust political institutions. Patriots are ready to do the same for their own country. Sometimes the cosmopolitan liberals and patriots would fight on the same side and sometimes on the opposite sides of the conflict. Thus the former would join the latter in the defense of Serbia against Austria-Hungary (in 1914 but would oppose the white Southerner patriots in the American Civil War (in 1861. In this paper I argue that fighting and killing for one’s country is, in both of those cases, different from the defense of one’s own life and the lives of those who cannot defend themselves. Killing for one’s country is killing in order to fulfill a particular political preference. The same is the case with fighting for the abolition of a profoundly unjust political institution. It is not amoral or immoral to refuse to kill for any one of these two political preferences because there is no reason to believe that either political preference trumps our moral constraints against killing.
A Compound Algorithm of Denoising Using Second-Order and Fourth-Order Partial Differential Equations
Institute of Scientific and Technical Information of China (English)
Qianshun Chang; Xuecheng Tai; Lily Xing
2009-01-01
In this paper, we propose a compound algorithm for the image restoration. The algorithm is a convex combination of the ROF model and the LLT model with a parameter function 6. The numerical experiments demonstrate that our compound algorithm is efficient and preserves the main advantages of the two models. In particular, the errors of the compound algorithm in L2 norm between the exact images and corresponding restored images are the smallest among the three models. For images with strong noises, the restored images of the compound algorithm are the best in the corresponding restored images. The proposed algorithm combines the fixed point method, an improved AMG method and the Krylov acceleration. It is found that the combination of these methods is efficient and robust in the image restoration.
Directory of Open Access Journals (Sweden)
Rubén Mercado
1997-04-01
Full Text Available Only three cases of human infection by anisakid nematodes have been reported in Chile since 1976. In the present case, an anisakid worm, identified as a fourth-stage Pseudoterranova decipiens larva, was removed with a gastroendoscopic biopsy clipper from the stomach of a 45 year-old man from southern Chile. The patient, who presented acute epigastric pain and a continuous sensation of having an empty stomach, reported having eaten smoked fish. The worm was fixed in 70% ethanol and cleaned in lactophenol for morphological study. The morphometric characteristics of the worm are described and drawn. Anisakid larvae in fish flesh can be killed by freezing or cooking.
Killing superalgebras for Lorentzian four-manifolds
de Medeiros, Paul; Figueroa-O'Farrill, José; Santi, Andrea
2016-06-01
We determine the Killing superalgebras underpinning field theories with rigid unextended supersymmetry on Lorentzian four-manifolds by re-interpreting them as filtered deformations of mathbb{Z} -graded subalgebras with maximum odd dimension of the N = 1 Poincaré superalgebra in four dimensions. Part of this calculation involves computing a Spencer cohomology group which, by analogy with a similar result in eleven dimensions, prescribes a notion of Killing spinor, which we identify with the defining condition for bosonic supersymmetric backgrounds of minimal off-shell supergravity in four dimensions. We prove that such Killing spinors always generate a Lie superalgebra, and that this Lie superalgebra is a filtered deformation of a subalgebra of the N = 1 Poincaré superalgebra in four dimensions. Demanding the flatness of the connection defining the Killing spinors, we obtain equations satisfied by the maximally supersymmetric backgrounds. We solve these equations, arriving at the classification of maximally supersymmetric backgrounds whose associated Killing superalgebras are precisely the filtered deformations we classify in this paper.
Mech, L. David; Nelson, Michael E.
2013-01-01
The age structure of Moose (Alces alces) killed by gray Wolves (Canis lupus) is available from only two national parks in the united States where hunting by people is not allowed and from three areas in Alaska where Moose are hunted (Mech 1966; Peterson et al.1984; Ballard et al. 1987; Mech et al. 1998). The samples of Moose killed by gray Wolves from each hunted area are relatively small (47–117), given that Moose live to 20 or more years (Passmore et al. 1955). This article adds age data from another 77 Moose killed by gray Wolves from a fourth (lightly) human-hunted area and assesses the age structure of all the samples.
33 CFR 117.801 - Newtown Creek, Dutch Kills, English Kills and their tributaries.
2010-07-01
... the Grand Street/Avenue Bridge, mile 3.1, across Newtown Creek (East Branch) between Brooklyn and..., DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements New York § 117... apply to all bridges across Newtown Creek, Dutch Kills, English Kills, and their tributaries: (1) The...
2010-10-12
... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF HOMELAND SECURITY Coast Guard 33 CFR Part 117 Drawbridge Operation Regulations; Newtown Creek, Dutch Kills, English Kills, and Their Tributaries, NY, Maintenance AGENCY: Coast Guard, DHS. ACTION: Notice of...
2010-06-01
... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF HOMELAND SECURITY Coast Guard 33 CFR Part 117 Drawbridge Operation Regulations; Newtown Creek, Dutch Kills, English Kills, and Their Tributaries, NY, Maintenance AGENCY: Coast Guard, DHS. ACTION: Notice of...
9 CFR 113.206 - Wart Vaccine, Killed Virus.
2010-01-01
... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Wart Vaccine, Killed Virus. 113.206... AGRICULTURE VIRUSES, SERUMS, TOXINS, AND ANALOGOUS PRODUCTS; ORGANISMS AND VECTORS STANDARD REQUIREMENTS Killed Virus Vaccines § 113.206 Wart Vaccine, Killed Virus. Wart Vaccine, Killed Virus, shall be...
Axial symmetry and conformal Killing vectors
Mars, M; Mars, Marc; Senovilla, Jose M.M.
1993-01-01
Axisymmetric spacetimes with a conformal symmetry are studied and it is shown that, if there is no further conformal symmetry, the axial Killing vector and the conformal Killing vector must commute. As a direct consequence, in conformally stationary and axisymmetric spacetimes, no restriction is made by assuming that the axial symmetry and the conformal timelike symmetry commute. Furthermore, we prove that in axisymmetric spacetimes with another symmetry (such as stationary and axisymmetric or cylindrically symmetric spacetimes) and a conformal symmetry, the commutator of the axial Killing vector with the two others mush vanish or else the symmetry is larger than that originally considered. The results are completely general and do not depend on Einstein's equations or any particular matter content.
'Total disability' and the wrongness of killing.
Omelianchuk, Adam
2015-08-01
Walter Sinnott-Armstrong and Franklin G Miller recently argued that the wrongness of killing is best explained by the harm that comes to the victim, and that 'total disability' best explains the nature of this harm. Hence, killing patients who are already totally disabled is not wrong. I maintain that their notion of total disability is ambiguous and that they beg the question with respect to whether there are abilities left over that remain relevant for the goods of personhood and human worth. If these goods remain, then something more is lost in death than in 'total disability,' and their explanation of what makes killing wrong comes up short. But if total disability is equivalent with death, then their argument is an interesting one.
Fourth Semiannual Report to the Congress by the United States Atomic Energy Commission, July 1948
Energy Technology Data Exchange (ETDEWEB)
Lilienthal, David E.; Bacher, Robert F.; Pike, Sumner T.; Strauss, Lewis L.; Waymack, William W.
1948-07-01
The document includes the letter of submittal and the Fourth semiannual report. These reports are called for pursuant to Section 17 of the Atomic Energy Act of 1946. This fourth report incorporates some changes to the report. In order to make these reports of maximum value to Members of Congress, the Commission has prepared this mid-year report as a specialized document giving a comprehensive account of several major phases of the atomic energy program.
Ambiguities in 'killing' and 'letting die'.
Atkinson, G M
1983-05-01
In a recent article Carla Kary (1980) attempts to show that there can be a significant moral difference between instances of killing and letting die. I shall maintain in Section I that Kary's argument is somewhat weakened by her failure to note an important ambiguity in the notion of killing a person. I shall also argue in Section II that a similar ambiguity affects the notion of letting someone die, and that failure to note this latter ambiguity also weakens the position developed by Robert Coburn (1980) with regard to defective newborns.
On the algebraic structure of Killing superalgebras
Figueroa-O'Farrill, José
2016-01-01
We study the algebraic structure of the Killing superalgebra of a supersymmetric $11$-dimensional supergravity background and show that it is isomorphic to a filtered deformation of a $\\mathbb Z$-graded subalgebra of the Poincar\\'e superalgebra. We then re-interpret the classification problem for backgrounds which preserve more than half of the supersymmetry as the classification problem of certain admissible filtered subdeformations of the Poincar\\'e superalgebra. In particular we relate the bosonic field equations of $11$-dimensional supergravity to the Jacobi identity of the Killing superalgebra and show in this way that preserving more than half the supersymmetry implies the bosonic field equations.
"Drone Killings in Principle and in Practice"
DEFF Research Database (Denmark)
Dige, Morten
2017-01-01
to argue that what we see in the real world cases of drone killings is not merely an accidental or contingent use of drone technology. The real life use reflects to a large extent features that are inherent of the dominant drone systems that has been developed to date. What is being imagined "in principle......" is thus to a large extent drone killings in dreamland. I use an historic example as a point of reference and departure: the debate over the lawfulness of nuclear weapons....
Fourth Generation Leptons and Muon $g-2$
Hou, Wei-Shu; Ma, Chien-Yi
2008-01-01
We consider the contributions to $g_\\mu-2$ from fourth generation heavy neutral and charged leptons, $N$ and $E$, at the one-loop level. Diagrammatically, there are two types of contributions: boson-boson-$N$, and $E$-$E$-boson in the loop diagram. In general, the effect from $N$ is suppressed by off-diagonal lepton mixing matrix elements. For $E$, we consider flavor changing neutral couplings arising from various New Physics models, which are stringently constrained by $\\mu\\to e\\gamma$. We assess how the existence of a fourth generation would affect these New Physics models.
The Fourth (A)ATSR Data Reprocessing
Goryl, Philippe; Cocevar, Pauline; Done, Fay; Aatsr Quality Working Group
2016-08-01
This paper aims to inform users of the upcoming Fourth Reprocessing of ATSR-1, ATSR-2 and AATSR data. The main objective of the Fourth Reprocessing is to generate (A)ATSR Level 1B data products in a similar format to SLSTR products from Sentinel-3. In this way, users can easily access the 20-year dataset from the ERS and ENVISAT (A)ATSR missions and carry the analysis forward into the Sentinel era. In addition to the product format change, the dataset will build on the improvements implemented in the Third Reprocessing, and will contain further improvements and enhancements, as described below.
Killing Hitler: A Writer's Journey and Angst.
Thaler, Paul
2002-01-01
Describes the author's experiences in preparing a talk that "evokes the specter" of Adolf Hitler and in writing an historical account of a British plot to kill Hitler. Address the question of why the British allowed him to live that final year of the war. Muses on why scholars write, and the impact of violence and terrorism. (SG)
A moral dilemma: killing and letting die.
Johnson, K
Most health care professionals believe that there is a clear difference between killing and letting die, i.e. between active and passive euthanasia. Philosophers, however, have repeatedly attacked the moral validity of their argument. This article explores various related issues and theoretical approaches to the distinction between acts and omissions.
Killing Hitler: A Writer's Journey and Angst.
Thaler, Paul
2002-01-01
Describes the author's experiences in preparing a talk that "evokes the specter" of Adolf Hitler and in writing an historical account of a British plot to kill Hitler. Address the question of why the British allowed him to live that final year of the war. Muses on why scholars write, and the impact of violence and terrorism. (SG)
Gas Well Blowout Kills 243 People
Institute of Scientific and Technical Information of China (English)
无
2003-01-01
@@ At least 243 people have been killed and scores of others poisoned in a devastating blowout at a natural gas field in Southwest China's Chongqing municipality on December 24. The accident happened at the Chuandongbei gas field in Kaixian county of Chongqing municipality.
School Shootings; Standards Kill Students and Society
Angert, Betsy L.
2008-01-01
School shootings have been in the news of late. People ponder what occurs in classrooms today. Why would a young person wish to take a life? Within educational institutions, the killings are a concern. In our dire attempt to teach the children and ensure student success, it seems many of our offspring are lost. Some students feel separate from…
Walk to the Fourth World Conference on Women
Institute of Scientific and Technical Information of China (English)
1995-01-01
China’s First Data Base of Women’s Documents Emerges IN order to greet the UN Fourth World Conference on Women and promote the academic exchange of women’s studies at home and abroad, China’s first data base of women’s documents, which was developed by the Research Department of Women’s Studies of the All-China Women’s Federation opened to the public this March. China’s women’s studies programs started in the 1980s.
Contagion in Mass Killings and School Shootings.
Towers, Sherry; Gomez-Lievano, Andres; Khan, Maryam; Mubayi, Anuj; Castillo-Chavez, Carlos
2015-01-01
Several past studies have found that media reports of suicides and homicides appear to subsequently increase the incidence of similar events in the community, apparently due to the coverage planting the seeds of ideation in at-risk individuals to commit similar acts. Here we explore whether or not contagion is evident in more high-profile incidents, such as school shootings and mass killings (incidents with four or more people killed). We fit a contagion model to recent data sets related to such incidents in the US, with terms that take into account the fact that a school shooting or mass murder may temporarily increase the probability of a similar event in the immediate future, by assuming an exponential decay in contagiousness after an event. We find significant evidence that mass killings involving firearms are incented by similar events in the immediate past. On average, this temporary increase in probability lasts 13 days, and each incident incites at least 0.30 new incidents (p = 0.0015). We also find significant evidence of contagion in school shootings, for which an incident is contagious for an average of 13 days, and incites an average of at least 0.22 new incidents (p = 0.0001). All p-values are assessed based on a likelihood ratio test comparing the likelihood of a contagion model to that of a null model with no contagion. On average, mass killings involving firearms occur approximately every two weeks in the US, while school shootings occur on average monthly. We find that state prevalence of firearm ownership is significantly associated with the state incidence of mass killings with firearms, school shootings, and mass shootings.
Contagion in Mass Killings and School Shootings.
Directory of Open Access Journals (Sweden)
Sherry Towers
Full Text Available Several past studies have found that media reports of suicides and homicides appear to subsequently increase the incidence of similar events in the community, apparently due to the coverage planting the seeds of ideation in at-risk individuals to commit similar acts.Here we explore whether or not contagion is evident in more high-profile incidents, such as school shootings and mass killings (incidents with four or more people killed. We fit a contagion model to recent data sets related to such incidents in the US, with terms that take into account the fact that a school shooting or mass murder may temporarily increase the probability of a similar event in the immediate future, by assuming an exponential decay in contagiousness after an event.We find significant evidence that mass killings involving firearms are incented by similar events in the immediate past. On average, this temporary increase in probability lasts 13 days, and each incident incites at least 0.30 new incidents (p = 0.0015. We also find significant evidence of contagion in school shootings, for which an incident is contagious for an average of 13 days, and incites an average of at least 0.22 new incidents (p = 0.0001. All p-values are assessed based on a likelihood ratio test comparing the likelihood of a contagion model to that of a null model with no contagion. On average, mass killings involving firearms occur approximately every two weeks in the US, while school shootings occur on average monthly. We find that state prevalence of firearm ownership is significantly associated with the state incidence of mass killings with firearms, school shootings, and mass shootings.
Contagion in Mass Killings and School Shootings
Towers, Sherry; Gomez-Lievano, Andres; Khan, Maryam; Mubayi, Anuj; Castillo-Chavez, Carlos
2015-01-01
Background Several past studies have found that media reports of suicides and homicides appear to subsequently increase the incidence of similar events in the community, apparently due to the coverage planting the seeds of ideation in at-risk individuals to commit similar acts. Methods Here we explore whether or not contagion is evident in more high-profile incidents, such as school shootings and mass killings (incidents with four or more people killed). We fit a contagion model to recent data sets related to such incidents in the US, with terms that take into account the fact that a school shooting or mass murder may temporarily increase the probability of a similar event in the immediate future, by assuming an exponential decay in contagiousness after an event. Conclusions We find significant evidence that mass killings involving firearms are incented by similar events in the immediate past. On average, this temporary increase in probability lasts 13 days, and each incident incites at least 0.30 new incidents (p = 0.0015). We also find significant evidence of contagion in school shootings, for which an incident is contagious for an average of 13 days, and incites an average of at least 0.22 new incidents (p = 0.0001). All p-values are assessed based on a likelihood ratio test comparing the likelihood of a contagion model to that of a null model with no contagion. On average, mass killings involving firearms occur approximately every two weeks in the US, while school shootings occur on average monthly. We find that state prevalence of firearm ownership is significantly associated with the state incidence of mass killings with firearms, school shootings, and mass shootings. PMID:26135941
Singapore: The Fourth Way in Action?
Hargreaves, Andy
2012-01-01
This article has two main objectives. It first outlines the first three waves of change termed by Hargreaves and Shirley (The Fourth Way: The inspiring future for educational change. Thousand Oaks, CA: Corwin Press, "2009") as the First, Second and Third Way that defined global educational policy and practice since the 1960s. It then…
Teaching Fourth Generation Evaluation through Monologue Interpretation.
Hepburn, Eric; Sparks, Cheryl
1992-01-01
This article illustrates the use of monologue interpretation, in which an interpreter illuminates issues in a speaker's monologue to translate theoretical pedagogical material into usable classroom applications. The example shows how the tenets of Guba and Lincoln's (1989) Responsive Constructivist Fourth Generation Model were presented via…
The Fourth Basic: Computer Skills. Final Report.
Hardin County Board of Education, Elizabethtown, KY.
Traditionally, the fundamental goal of all American education has been to provide students with adequate competencies in reading, writing, and mathematics. A year-long project, conducted at three high schools in Hardin County, Kentucky, provided for the development of a fourth basic: computer skills. Through this project, computer skills were…
Vocabulary Strategies for a Fourth Grade Classroom
Howell, Gina
2012-01-01
For this project I worked with twelve of my fourth grade students from a local school in the southwestern part of Stokes County, North Carolina on increasing their vocabulary skills through the development and implementation of seven vocabulary strategies. During the Literature Review I came across the following seven strategies: Prediction;…
An experiment with the fourth Futamura projection
DEFF Research Database (Denmark)
Glück, Robert
2010-01-01
We have experimentally validated the theoretical insight, that a compiler generator is an Ershov generating extension of a program specializer, by showing that an existing offline partial evaluator can perform the fourth Futamura projection. Specifically, an online and an offline partial evaluator...
The Fourth Domain of Educational Objectives: Induction.
Holleman, Wes
1985-01-01
Tests the claim to comprehensiveness of Bloom's taxonomy of educational objectives by analyzing educational objectives of some freshmen orientation programs and those connected with human developmental tasks. It is concluded that the taxonomy should be enlarged with a fourth domain: actual induction into tasks for which students are being…
Directory of Open Access Journals (Sweden)
J. T. Atosuo
2011-01-01
Full Text Available A recombinant Escherichia coli K-12 strain, transformed with a modified bacterial luciferase gene (luxABCDE from Photorhabdus luminescens, was constructed in order to monitor the activity of various antimicrobial agents on a real-time basis. This E. coli-lux emitted, without any addition of substrate, constitutive bioluminescence (BL, which correlated to the number of viable bacterial cells. The decrease in BL signal correlated to the number of killed bacterial cells. Antimicrobial activity of hydrogen peroxide (H2O2 and myeloperoxidase (MPO was assessed. In high concentrations, H2O2 alone had a bacteriocidic function and MPO enhanced this killing by forming hypochlorous acid (HOCl. Taurine, the known HOCl scavenger, blocked the killing by MPO. When E. coli-lux was incubated with neutrophils, similar killing kinetics was recorded as in H2O2/MPO experiments. The opsonization of bacteria enhanced the killing, and the maximum rate of the MPO release from lysosomes coincided with the onset of the killing.
Atosuo, J T; Lilius, E-M
2011-01-01
A recombinant Escherichia coli K-12 strain, transformed with a modified bacterial luciferase gene (luxABCDE) from Photorhabdus luminescens, was constructed in order to monitor the activity of various antimicrobial agents on a real-time basis. This E. coli-lux emitted, without any addition of substrate, constitutive bioluminescence (BL), which correlated to the number of viable bacterial cells. The decrease in BL signal correlated to the number of killed bacterial cells. Antimicrobial activity of hydrogen peroxide (H(2)O(2)) and myeloperoxidase (MPO) was assessed. In high concentrations, H(2)O(2) alone had a bacteriocidic function and MPO enhanced this killing by forming hypochlorous acid (HOCl). Taurine, the known HOCl scavenger, blocked the killing by MPO. When E. coli-lux was incubated with neutrophils, similar killing kinetics was recorded as in H(2)O(2)/MPO experiments. The opsonization of bacteria enhanced the killing, and the maximum rate of the MPO release from lysosomes coincided with the onset of the killing.
Finite difference order doubling in two dimensions
Energy Technology Data Exchange (ETDEWEB)
Killingbeck, John P [Mathematics Centre, University of Hull, Hull HU6 7RX (United Kingdom); Jolicard, Georges [Universite de Franche-Comte, Institut Utinam (UMR CNRS 6213), Observatoire de Besancon, 41 bis Avenue de l' Observatoire, BP1615, 25010 Besancon cedex (France)
2008-03-28
An order doubling process previously used to obtain eighth-order eigenvalues from the fourth-order Numerov method is applied to the perturbed oscillator in two dimensions. A simple method of obtaining high order finite difference operators is reported and an odd parity boundary condition is found to be effective in facilitating the smooth operation of the order doubling process.
Dirac operators and Killing spinors with torsion; Dirac-Operatoren und Killing-Spinoren mit Torsion
Energy Technology Data Exchange (ETDEWEB)
Becker-Bender, Julia
2012-12-17
On a Riemannian spin manifold with parallel skew torsion, we use the twistor operator to obtain an eigenvalue estimate for the Dirac operator with torsion. We consider the equality case in dimensions four and six. In odd dimensions we describe Sasaki manifolds on which equality in the estimate is realized by Killing spinors with torsion. In dimension five we characterize all Killing spinors with torsion and obtain certain naturally reductive spaces as exceptional cases.
Killing, letting die, and withdrawing aid.
McMahan, Jeff
1993-01-01
One of the aims of this article is to contribute to the identification of the empirical criteria governing the use of the concepts of killing and letting die. I will not attempt a comprehensive analysis of the concepts but will limit the inquiry to certain problematic cases -- namely, cases involving the removal or withdrawal of life-supporting aid or protection. The analysis of these cases will, however, shed light on the criteria for distinguishing killing and letting die in other cases as well. My overall aims in the article are partly constructive and partly skeptical. I hope to advance our understanding of the nature of the distinction between killing and letting die. This, I believe, will enable us to defend the moral relevance of the distinction against certain objections -- in particular, objections that claim that the distinction fails to coincide with commonsense moral intuitions. Yet I will suggest that, as we get clearer about the nature of the distinction and the sources of its intuitive appeal, it may seem that the intuitions it supports are not so well grounded as one could wish.
Using fourth-generation evaluation in nursing.
Swenson, M M
1991-03-01
Evaluation is disciplined inquiry undertaken to determine the value, including merit and worth, of some entity: a curriculum program, a clinical intervention, an academic course, a care plan. An evaluation is conducted to improve or refine the thing being evaluated (evaluand) or to assess its impact and effectiveness. Evaluation in nursing has been designed using various positivistic and post-positivistic models in the first three "generations" in the evolution of evaluation practice. This article describes a new model of nursing evaluation more consistent with a nursing paradigm than with a traditional, scientific, medical paradigm. Responsive nursing evaluation informs and empowers all those involved in its outcomes (the stakeholders) when framed within the research stance called naturalistic or constructivist inquiry. The fourth-generation-evaluation approach of Guba and Lincoln (1989) is consistent with a nursing paradigm and a constructivist approach. Fourth-generation evaluation is presented with specific application to nursing evaluation.
The Fourth Law of Behavior Genetics.
Chabris, Christopher F; Lee, James J; Cesarini, David; Benjamin, Daniel J; Laibson, David I
2015-07-01
Behavior genetics is the study of the relationship between genetic variation and psychological traits. Turkheimer (2000) proposed "Three Laws of Behavior Genetics" based on empirical regularities observed in studies of twins and other kinships. On the basis of molecular studies that have measured DNA variation directly, we propose a Fourth Law of Behavior Genetics: "A typical human behavioral trait is associated with very many genetic variants, each of which accounts for a very small percentage of the behavioral variability." This law explains several consistent patterns in the results of gene discovery studies, including the failure of candidate gene studies to robustly replicate, the need for genome-wide association studies (and why such studies have a much stronger replication record), and the crucial importance of extremely large samples in these endeavors. We review the evidence in favor of the Fourth Law and discuss its implications for the design and interpretation of gene-behavior research.
The "fourth dimension" of gene transcription.
O'Malley, Bert W
2009-05-01
The three dimensions of space provide our relationship to position on the earth, but the fourth dimension of time has an equally profound influence on our lives. Everything from light and sound to weather and biology operate on the principle of measurable temporal periodicity. Consequently, a wide variety of time clocks affect all aspects of our existence. The annual (and biannual) cycles of activity, metabolism, and mating, the monthly physiological clocks of women and men, and the 24-h diurnal rhythms of humans are prime examples. Should it be surprising to us that the fourth dimension also impinges upon gene expression and that the genome itself is regulated by the fastest running of all biological clocks? Recent evidence substantiates the existence of such a ubiquitin-dependent transcriptional clock that is based upon the activation and destruction of transcriptional coactivators.
Imitatio Christi in the fourth gospel
Directory of Open Access Journals (Sweden)
D.G. van der Merwe
2001-08-01
Full Text Available Imitatio Christi is a concept which, although not referred to explicitly in the Fourth Gospel, is clearly spelled out in relation to the agency motif occurring in the Gospel. The disciples of Jesus have been appointed as his agents to continue his mission after his departure to his Father. In giving this message through to his readers, the Fourth Evangelist refers to Jesus' calling of his disciples, [Foreign font omitted]; pictures Jesus as [Foreign font omitted]; uses [Foreign font omitted] (the particle of comparison to compare the lives of the disciples with that of Jesus; points out the tasks the disciples had to perform after Jesus' ascension and, finally, indicates how Jesus dwells in his disciples through the Paraclete.
Fourth international conference on Networks & Communications
Meghanathan, Natarajan; Nagamalai, Dhinaharan; Computer Networks & Communications (NetCom)
2013-01-01
Computer Networks & Communications (NetCom) is the proceedings from the Fourth International Conference on Networks & Communications. This book covers theory, methodology and applications of computer networks, network protocols and wireless networks, data communication technologies, and network security. The proceedings will feature peer-reviewed papers that illustrate research results, projects, surveys and industrial experiences that describe significant advances in the diverse areas of computer networks & communications.
Fourth World Theory: The Evolution of . . .
2014-01-01
Fourth World theory is a methodology for examining and developing greater understanding of the extent of the distress and abandonment commonly found in the cores of American cities resulting from de-industrialization, historic segregation and discrimination patterns, suburban sprawl, erosion of a viable tax base, racism, inability to embrace the concept of desegregation and civil rights legislation, fear, despair, crumbling infrastructure systems, disinvestment in urban school systems, and en...
Supernumerary maxillary and Mandibular Fourth Molars.
1981-09-23
in earlier primates then in man. Hyperdontia has occasionally been associated with clefts of the lip and palate , I0 cleldocranial dysostosis, 2...year-old black male was seen In the clinic for treatment of pain which was originating from a deep carious lesion in the mandibular left second molar...incompletely formed impacted left fourth molar and right bicuspid were also noted. Case III. A 24-year-old male was seen in the clinic for treatment of
The fourth China Bioanalysis Forum Annual Meeting.
Tang, Daniel; Zhong, Dafang; Dong, Kelly
2017-01-01
The fourth China Bioanalysis Forum annual conference, co-organized with the Nanjing International Drug Metabolism Conference, was successfully held in Nanjing, China, between 24-26 June 2016. The theme of the conference was 'how to conduct regulated bioanalysis under China Food and Drug Administration (CFDA) regulations'. In addition, several hot topics including bioanalytical challenges, solutions for biomarkers, antidrug antibody (antibody-drug conjugates) and biologics were discussed. This Conference Report summarizes the major discussion topics from the conference.
Art meets mathematics in the fourth dimension
Lipscomb, Stephen Leon
2014-01-01
To see objects that live in the fourth dimension we humans would need to add a fourth dimension to our three-dimensional vision. An example of such an object that lives in the fourth dimension is a hyper-sphere or “3-sphere”. The quest to imagine the elusive 3-sphere has deep historical roots: medieval poet Dante Alighieri, in his circa 1300 AD Divine Comedy, used a 3-sphere to convey his allegorical vision of the Christian afterlife. In 1917, Albert Einstein visualized the universe, at each instant in time, as a 3-sphere. He described his representation as “…the place where the reader’s imagination boggles. Nobody can imagine this thing.” Over time, however, our understanding of the concept of dimension evolved. By 2003, a researcher had successfully rendered into human vision the structure of a 4-web (think of an every increasingly-dense spider’s web). In this text Stephen Lipscomb takes his innovative dimension theory research a step further, using the 4-web to reveal a new partial image of a...
Telling time in the Fourth Gospel
Directory of Open Access Journals (Sweden)
Jerome H. Neyrey
2008-01-01
Full Text Available When we begin the task of telling time in the Fourth Gospel, we bring something not found in any previous study, namely, a model of time articulated by cross- ultural anthropologists (Bordieu, in Pitt-Rivers 1963:55-72, Ayoade, in Wright 1984:71-89. As much as we admire Davies’ study, she has no notes to her chapter on time nor any citations in her bibliography to indicate that she has any conversation partners, much less cultural experts, a deficit to be filled in this study. Learning to tell time entails three theoretical considerations: a definition of time, key classifications of it, and special attention to what the ancients meant by past, present and future. With these lenses we are prepared to do as thorough a study as we can on telling time in the Fourth Gospel. As we consider each classification, we will suggest a brief meaning of it from the experts on time, then present a body of Greco-Roman materials illustrative of the classification, and finally use it to gather and interpret data in John. Proving the native existence of these classifications for telling time in antiquity is essential for readers to have a background against which to compare their usage with that of the Fourth Gospel.
9 CFR 113.214 - Parvovirus Vaccine, Killed Virus (Canine).
2010-01-01
... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Parvovirus Vaccine, Killed Virus... REQUIREMENTS Killed Virus Vaccines § 113.214 Parvovirus Vaccine, Killed Virus (Canine). Parvovirus Vaccine... established as follows: (1) Twenty-five parvovirus susceptible dogs (20 vaccinates and 5 controls) shall be...
9 CFR 113.203 - Feline Panleukopenia Vaccine, Killed Virus.
2010-01-01
... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Feline Panleukopenia Vaccine, Killed... REQUIREMENTS Killed Virus Vaccines § 113.203 Feline Panleukopenia Vaccine, Killed Virus. Feline Panleukopenia... shall be individually tested for neutralizing antibody against feline panleukopenia virus to...
9 CFR 113.201 - Canine Distemper Vaccine, Killed Virus.
2010-01-01
... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Canine Distemper Vaccine, Killed Virus... REQUIREMENTS Killed Virus Vaccines § 113.201 Canine Distemper Vaccine, Killed Virus. Canine Distemper Vaccine... canine distemper susceptible dogs (20 vaccinates and 5 controls) shall be used as test animals....
9 CFR 113.204 - Mink Enteritis Vaccine, Killed Virus.
2010-01-01
... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Mink Enteritis Vaccine, Killed Virus... REQUIREMENTS Killed Virus Vaccines § 113.204 Mink Enteritis Vaccine, Killed Virus. Mink Enteritis Vaccine... have developed mink enteritis following inoculation with virulent mink enteritis virus. Each...
9 CFR 113.205 - Newcastle Disease Vaccine, Killed Virus.
2010-01-01
... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Newcastle Disease Vaccine, Killed... REQUIREMENTS Killed Virus Vaccines § 113.205 Newcastle Disease Vaccine, Killed Virus. Newcastle Disease Vaccine... Newcastle disease virus supplied by or approved by Veterinary Services and the vaccinates observed each...
It's not just conflict that motivates killing of orangutans.
Directory of Open Access Journals (Sweden)
Jacqueline T Davis
Full Text Available We investigated why orangutans are being killed in Kalimantan, Indonesia, and the role of conflict in these killings. Based on an analysis of interview data from over 5,000 respondents in over 450 villages, we also assessed the socio-ecological factors associated with conflict and non-conflict killings. Most respondents never kill orangutans. Those who reported having personally killed an orangutan primarily did so for non-conflict reasons; for example, 56% of these respondents said that the reason they had killed an orangutan was to eat it. Of the conflict-related reasons for killing, the most common reasons orangutans were killed was fear of orangutans or in self-defence. A similar pattern was evident among reports of orangutan killing by other people in the villages. Regression analyses indicated that religion and the percentage of intact forest around villages were the strongest socio-ecological predictors of whether orangutans were killed for conflict or non-conflict related reasons. Our data indicate that between 44,170 and 66,570 orangutans were killed in Kalimantan within the respondents' active hunting lifetimes: between 12,690 and 29,024 for conflict reasons (95%CI and between 26,361 and 41,688 for non-conflict reasons (95% CI. These findings confirm that habitat protection alone will not ensure the survival of orangutans in Indonesian Borneo, and that effective reduction of orangutan killings is urgently needed.
9 CFR 113.212 - Bursal Disease Vaccine, Killed Virus.
2010-01-01
... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Bursal Disease Vaccine, Killed Virus..., DEPARTMENT OF AGRICULTURE VIRUSES, SERUMS, TOXINS, AND ANALOGOUS PRODUCTS; ORGANISMS AND VECTORS STANDARD REQUIREMENTS Killed Virus Vaccines § 113.212 Bursal Disease Vaccine, Killed Virus. Bursal Disease...
9 CFR 113.208 - Avian Encephalomyelitis Vaccine, Killed Virus.
2010-01-01
..., Killed Virus. 113.208 Section 113.208 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE VIRUSES, SERUMS, TOXINS, AND ANALOGOUS PRODUCTS; ORGANISMS AND VECTORS STANDARD REQUIREMENTS Killed Virus Vaccines § 113.208 Avian Encephalomyelitis Vaccine, Killed Virus....
9 CFR 113.213 - Pseudorabies Vaccine, Killed Virus.
2010-01-01
... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Pseudorabies Vaccine, Killed Virus..., DEPARTMENT OF AGRICULTURE VIRUSES, SERUMS, TOXINS, AND ANALOGOUS PRODUCTS; ORGANISMS AND VECTORS STANDARD REQUIREMENTS Killed Virus Vaccines § 113.213 Pseudorabies Vaccine, Killed Virus. Pseudorabies Vaccine,...
A novel circuit architecture for fourth subharmonie mixers
Institute of Scientific and Technical Information of China (English)
Yao Changfei; Xu Conghai; Zhou Ming; Luo Yunsheng
2012-01-01
A circuit topology for high-order subharmonic (SH) mixers is described.By phase cancellation of idle frequency components,the SH mixer circuit can eliminate the complicated design procedure of idle frequency circuits.Similarly,the SH mixer circuit can achieve a high port isolation by phase cancellation of the leakage LO,RF and idle frequency signals.Based on the high-order SH mixer architecture,a new Ka-band fourth SH mixer is analyzed and designed,it shows the lowest measured conversion loss of 8.3 dB at 38.4 GHz and the loss is lower than 10.3 dB in 34-39 GHz.Measured LO-IF,RF-LO,RF-IF port isolation are better than 30.7 dB,22.9dB and 46.5 dB,respectively.
Anorexia: an early sign of fourth ventricle astrocytoma in children.
Leroy, Henri-Arthur; Baroncini, Marc; Delestret, Isabelle; Florent, Vincent; Vinchon, Matthieu
2014-12-01
Paediatric low-grade astrocytomas of the fourth ventricle are rare tumours, generally revealed by hydrocephalus. However, some patients present with a history of severe anorexia. It might be a harbinger, which if recognized, could lead to earlier diagnosis. We decided to examine our database in order to evaluate the incidence and signification of anorexia in this context. Retrospective monocentric study of cases of low-grade astrocytomas of the fourth ventricle operated between 1991 and 2012 in our paediatric neurosurgery department. We particularly observed the clinical presentation and long-term clinical, oncological and radiological evolution. Non-parametrical tests were used (Mann-Whitney, Fisher). We reviewed 34 cases, 31 pilocytic astrocytomas and 3 diffuse astrocytomas, 16 boys and 18 girls, (M/F ratio 0.89). Mean age at diagnosis was 8 years old. Seven presented with notable anorexia, the average BMI in this group was ≤2 standard deviation (SD); with clinical signs evolving for 11.5 months. Twenty-seven children had no anorexia; average BMI in this group was +1 SD, with clinical evolution for 6 months on an average of p anorexia, body mass index improved markedly in the postoperative follow-up, which lasted, on average, for 6 years. Anorexia with stunted body weight curve is a non-exceptional presentation in children with low-grade astrocytomas of the fourth ventricle. Unexplained or atypical anorexia with negative etiologic assessment should prompt cerebral imaging. Clinical improvement after surgical resection, could suggest a possible interaction between tumour tissue and appetite-suppressing peptide secretion.
Credito, Kim L.; Ednie, Lois M.; Jacobs, Michael R.; Appelbaum, Peter C.
1999-01-01
Time-kill studies examined the activities of telithromycin (HMR 3647), erythromycin A, azithromycin, clarithromycin, roxithromycin, clindamycin, pristinamycin, amoxicillin-clavulanate, and metronidazole against 11 gram-positive and gram-negative anaerobic bacteria. Time-kill studies were carried out with the addition of Oxyrase in order to prevent the introduction of CO2. Macrolide-azalide-ketolide MICs were 0.004 to 32.0 μg/ml. Of the latter group, telithromycin had the lowest MICs, especially against non-Bacteroides fragilis group strains, followed by azithromycin, clarithromycin, erythromycin A, and roxithromycin. Clindamycin was active (MIC ≤ 2.0 μg/ml) against all anaerobes except Peptostreptococcus magnus and Bacteroides thetaiotaomicron, while pristinamycin MICs were 0.06 to 4.0 μg/ml. Amoxicillin-clavulanate had MICs of ≤1.0 μg/ml, while metronidazole was active (MICs, 0.03 to 2.0 μg/ml) against all except Propionibacterium acnes. After 48 h at twice the MIC, telithromycin was bactericidal (≥99.9% killing) against 6 strains, with 99% killing of 9 strains and 90% killing of 10 strains. After 24 h at twice the MIC, 90, 99, and 99.9% killing of nine, six, and three strains, respectively, occurred. Lower rates of killing were seen at earlier times. Similar kill kinetics relative to the MIC were seen with other macrolides. After 48 h at the MIC, clindamycin was bactericidal against 8 strains, with 99 and 90% killing of 9 and 10 strains, respectively. After 24 h, 90% killing of 10 strains occurred at the MIC. The kinetics of clindamycin were similar to those of pristinamycin. After 48 h at the MIC, amoxicillin-clavulanate showed 99.9% killing of seven strains, with 99% killing of eight strains and 90% killing of nine strains. At four times the MIC, metronidazole was bactericidal against 8 of 10 strains tested after 48 h and against all 10 strains after 24 h; after 12 h, 99% killing of all 10 strains occurred. PMID:10428930
Blasius flow and heat transfer of fourth-grade fluid with slip
Institute of Scientific and Technical Information of China (English)
B SAHOO; S PONCET
2013-01-01
This investigation deals with the effects of slip, magnetic field, and non-Newtonian flow parameters on the flow and heat transfer of an incompressible, electrically conducting fourth-grade fluid past an infinite porous plate. The heat transfer analysis is carried out for two heating processes. The system of highly non-linear differential equations is solved by the shooting method with the fourth-order Runge-Kutta method for moderate values of the parameters. The effective Broyden technique is adopted in order to improve the initial guesses and to satisfy the boundary conditions at infinity. An exceptional cross-over is obtained in the velocity profile in the presence of slip. The fourth-grade fluid parameter is found to increase the momentum boundary layer thickness, whereas the slip parameter substantially decreases it. Similarly, the non-Newtonian fluid parameters and the slip have opposite effects on the thermal boundary layer thickness.
Survival probability of mutually killing Brownian motions and the O'Connell process
Katori, Makoto
2011-01-01
Recently O'Connell introduced an interacting diffusive particle system in order to study a directed polymer model in 1+1 dimensions. The infinitesimal generator of the process is a harmonic transform of the quantum Toda-lattice Hamiltonian by the Whittaker function. As a physical interpretation of this construction, we show that the O'Connell process without drift is realized as a system of mutually killing Brownian motions conditioned that all particles survive forever. When the characteristic length of interaction killing other particles goes to zero, the process is reduced to the noncolliding Brownian motion (the Dyson model).
7 CFR 51.2296 - Three-fourths half kernel.
2010-01-01
... 7 Agriculture 2 2010-01-01 2010-01-01 false Three-fourths half kernel. 51.2296 Section 51.2296 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards...-fourths half kernel. Three-fourths half kernel means a portion of a half of a kernel which has more...
Killing-Yano forms and Killing tensors on a warped space
Krtous, Pavel; Kolar, Ivan
2015-01-01
We formulate several criteria under which the symmetries associated with the Killing and Killing-Yano tensors on the base space can be lifted to the symmetries of the full warped geometry. The procedure is explicitly illustrated on several examples, providing new prototypes of spacetimes admitting such tensors. In particular, we study a warped product of two Kerr-NUT-(A)dS spacetimes and show that it gives rise to a new class of highly symmetric vacuum (with cosmological constant) black hole solutions that inherit many of the properties of the Kerr-NUT-(A)dS geometry.
McNally, Luke; Bernardy, Eryn; Thomas, Jacob; Kalziqi, Arben; Pentz, Jennifer; Brown, Sam P.; Hammer, Brian K.; Yunker, Peter J.; Ratcliff, William C.
2017-02-01
By nature of their small size, dense growth and frequent need for extracellular metabolism, microbes face persistent public goods dilemmas. Genetic assortment is the only general solution stabilizing cooperation, but all known mechanisms structuring microbial populations depend on the availability of free space, an often unrealistic constraint. Here we describe a class of self-organization that operates within densely packed bacterial populations. Through mathematical modelling and experiments with Vibrio cholerae, we show how killing adjacent competitors via the Type VI secretion system (T6SS) precipitates phase separation via the `Model A' universality class of order-disorder transition mediated by killing. We mathematically demonstrate that T6SS-mediated killing should favour the evolution of public goods cooperation, and empirically support this prediction using a phylogenetic comparative analysis. This work illustrates the twin role played by the T6SS, dealing death to local competitors while simultaneously creating conditions potentially favouring the evolution of cooperation with kin.
Micro-sociology of mass rampage killings.
Collins, Randall
2014-01-01
Spectacular but very rare violent events such as mass killings by habitual non-criminals cannot be explained by factors which are very widespread, such as possession of firearms, being a victim of bullying, an introvert, or a career failure. A stronger clue is clandestine preparation of attack by one or two individuals, against randomly chosen representatives of a hated collective identity. Mass killers develop a deep back-stage, obsessed with planning their attack, overcoming social inferiority and isolation by an emotion of clandestine excitement.
Mechanism involved in phagocytosis and killing of Listeria monocytogenes by Acanthamoeba polyphaga.
Akya, Alisha; Pointon, Andrew; Thomas, Connor
2009-10-01
Intra-cellular pathogen, Listeria monocytogenes, is capable of invasion and survival within mammalian cells. However, Acanthamoeba polyphaga trophozoites phagocytose and rapidly degrade Listeria cells. In order to provide more information on amoeba phagocytosis and killing mechanisms, this study used several inhibitor agents known to affect the phagocytosis and killing of bacteria by eukaryotes. Amoebae were pre-treated with mannose, cytochalasin D, wortmannin, suramin, ammonium chloride, bafilomycin A and monensin followed by co-culture with bacteria. Phagocytosis and killing of bacterial cells by amoeba trophozoites was assessed using plate counting methods and microscopy. The data presented indicates that actin polymerisation and cytoskeletal rearrangement are involved in phagocytosis of L. monocytogenes cells by A. polyphaga trophozoites. Further, both phagosomal acidification and phagosome-lysosome fusion are involved in killing and degradation of L. monocytogenes cells by A. polyphaga. However, the mannose-binding protein receptor does not play an important role in uptake of bacteria by amoeba trophozoites. In conclusion, this data reveals the similar principles of molecular mechanisms used by different types of eukaryotes in uptake and killing of bacteria.
Fourth Generation Leptons and Muon $g-2$
Hou, Wei-Shu; Ma, Chien-Yi
2008-01-01
We consider the contributions to $g_\\mu-2$ from fourth generation neutral and charged leptons, $N$ and $E$, at the one-loop level. Diagramatically, there are two types of contributions: boson-boson-$N$, and $E$-$E$-boson in the loop diagram. In general, the effect from $N$ is suppressed by off-diagonal PMNS matrix element $V_{N\\mu}$, from the Standard Model to the Two-Higgs Doublet Models. With contribution from $E$, we consider flavor changing neutral couplings.
Geometry, relativity and the fourth dimension
Rucker, Rudolf
1977-01-01
This is a highly readable, popular exposition of the fourth dimension and the structure of the universe. A remarkable pictorial discussion of the curved space-time we call home, it achieves even greater impact through the use of 141 excellent illustrations. This is the first sustained visual account of many important topics in relativity theory that up till now have only been treated separately.Finding a perfect analogy in the situation of the geometrical characters in Flatland, Professor Rucker continues the adventures of the two-dimensional world visited by a three-dimensional being to expl
Fourth international seminar on horizontal steam generators
Energy Technology Data Exchange (ETDEWEB)
Tuomisto, H. [ed.] [IVO Group, Vantaa (Finland); Purhonen, H. [ed.] [VTT, Espoo (Finland); Kouhia, V. [ed.] [Lappeenranta Univ. of Technology (Finland)
1997-12-31
The general objective of the International Seminars of Horizontal Steam Generator Modelling has been the improvement in understanding of realistic thermal hydraulic behaviour of the generators when performing safety analyses for VVER reactors. The main topics presented in the fourth seminar were: thermal hydraulic experiments and analyses, primary collector integrity, feedwater distributor replacement, management of primary-to-secondary leakage accidents and new developments in the VVER safety technology. The number of participants, representing designers and manufacturers of the horizontal steam generators, plant operators, engineering companies, research organizations, universities and regulatory authorities, was 70 from 10 countries.
Bar-Oz, Guy; Zeder, Melinda; Hole, Frank
2011-05-03
Continuous and intensive exploitation of wildlife resources by early agricultural societies had major ecological consequences in the ancient Near East. In particular, hunting strategies of post-Neolithic societies involving the mass killing of wild ungulates contributed to the eventual extirpation of a number of wild species. A remarkable deposit of bones of Persian gazelle (Gazella subgutarosa) from fourth millennium BCE levels at Tell Kuran in northeastern Syria provides insight into the unsustainable hunting practices that disrupted gazelle migratory patterns and helped set the course for the virtual extinction of this species and possibly other steppe species in the Levant. The social context of mass kills conducted during periods when people relied primarily on domestic livestock for animal resources sets them apart from the more targeted and sustainable practices of earlier periods, when wild animals were the major or sole source of animal protein.
Watkins, Marley W.; Wilson, Sharise M.; Kotz, Kasey M.; Carbone, Maria C.; Babula, Teresa
2006-01-01
Factor analysis was applied to the Wechsler Intelligence Scale for Children--Fourth Edition (WISC-IV) scores of 432 Pennsylvania students referred for evaluation for special education services to determine the factor structure of the WISC-IV with this population. A first-order, four-factor oblique solution that mirrored that found in the WISC-IV…
Mims, Wyn, M.; Lockley, Jeannie
2017-01-01
A fourth-grade teacher utilized action research in order to make data-driven decisions about reading interventions with her students. The teacher decided on a broad intervention, which was differentiating reading instruction, implemented differentiated instruction, collected data and continuously adjusted interventions based on monitoring data.…
Cognitive Development of Fourth Graders in a High-Stakes State.
Aagaard, Lola; Boram, Robert
Jean Piaget's classic theory of cognitive development would imply that the higher-order items on the Kentucky state assessment would only be possible for students well into concrete operations or beginning formal operations. The implication would be that Kentucky fourth graders who are not fully concrete yet may be hitting a developmental ceiling…
Fourth Grade Students' Drawing Interpretations of a Sport Education Soccer Unit
Mowling, Claire M.; Brock, Sheri J.; Hastie, Peter A.
2006-01-01
This study examined fourth grade students' representations of sport education through drawings in order to determine what students perceived as most important throughout their soccer season. The first objective was to determine whether student representations would follow the components of sport education (e.g., season, team affiliation, formal…
Where and How Wolves (Canis lupus) Kill Beavers (Castor canadensis).
Gable, Thomas D; Windels, Steve K; Bruggink, John G; Homkes, Austin T
2016-01-01
Beavers (Castor canadensis) can be a significant prey item for wolves (Canis lupus) in boreal ecosystems due to their abundance and vulnerability on land. How wolves hunt beavers in these systems is largely unknown, however, because observing predation is challenging. We inferred how wolves hunt beavers by identifying kill sites using clusters of locations from GPS-collared wolves in Voyageurs National Park, Minnesota. We identified 22 sites where wolves from 4 different packs killed beavers. We classified these kill sites into 8 categories based on the beaver-habitat type near which each kill occurred. Seasonal variation existed in types of kill sites as 7 of 12 (58%) kills in the spring occurred at sites below dams and on shorelines, and 8 of 10 (80%) kills in the fall occurred near feeding trails and canals. From these kill sites we deduced that the typical hunting strategy has 3 components: 1) waiting near areas of high beaver use (e.g., feeding trails) until a beaver comes near shore or ashore, 2) using vegetation, the dam, or other habitat features for concealment, and 3) immediately attacking the beaver, or ambushing the beaver by cutting off access to water. By identifying kill sites and inferring hunting behavior we have provided the most complete description available of how and where wolves hunt and kill beavers.
The Fourth Gravity Test and Quintessence Matter Field
Liu, Molin; Yu, Fei; Gui, Yuanxing
2010-01-01
After the previous work on gravitational frequency shift, light deflection (arXiv:1003.5296) and perihelion advance (arXiv:0812.2332), we calculate carefully the fourth gravity test, i.e. radar echo delay in a central gravity field surrounded by static free quintessence matter, in this paper. Through the Lagrangian method, we find the influence of the quintessence matter on the time delay of null particle is presence by means of an additional integral term. When the quintessence field vanishes, it reduces to the usual Schwarzschild case naturally. Meanwhile, we also use the data of the Viking lander from the Mars and Cassini spacecraft to Saturn to constrain the quintessence field. For the Viking case, the field parameter $\\alpha$ is under the order of $10^{-9}$. However, $\\alpha$ is under $10^{-18}$ for the Cassini case.
The fourth gravity test and quintessence matter field
Energy Technology Data Exchange (ETDEWEB)
Liu, Molin; Yu, Benhai [Xinyang Normal University, College of Physics and Electronic Engineering, Xinyang (China); Yu, Fei; Gui, Yuanxing [Dalian University of Technology, School of Physics and Optoelectronic Technology, Dalian (China)
2010-06-15
After the previous work on gravitational frequency shift, light deflection (Eur. Phys. J. C 59: 107-116, 2009) and perihelion advance (Eur. Phys. J. C 60: 175-179, 2009), we calculate carefully the fourth gravity test, i.e. radar echo delay in a central gravity field surrounded by static free quintessence matter, in this paper. Through the Lagrangian method, we find the influence of the quintessence matter on the time delay of null particle is presence by means of an additional integral term. When the quintessence field vanishes, it reduces to the usual Schwarzschild case naturally. Meanwhile, we also use the data of the Viking lander from the Mars and Cassini spacecraft to Saturn to constrain the quintessence field. For the Viking case, the field parameter {alpha} is under the order of 10{sup -9}. However, {alpha} is under 10{sup -18} for the Cassini case. (orig.)
The eyeball killer: serial killings with postmortem globe enucleation.
Coyle, Julie; Ross, Karen F; Barnard, Jeffrey J; Peacock, Elizabeth; Linch, Charles A; Prahlow, Joseph A
2015-05-01
Although serial killings are relatively rare, they can be the cause of a great deal of anxiety while the killer remains at-large. Despite the fact that the motivations for serial killings are typically quite complex, the psychological analysis of a serial killer can provide valuable insight into how and why certain individuals become serial killers. Such knowledge may be instrumental in preventing future serial killings or in solving ongoing cases. In certain serial killings, the various incidents have a variety of similar features. Identification of similarities between separate homicidal incidents is necessary to recognize that a serial killer may be actively killing. In this report, the authors present a group of serial killings involving three prostitutes who were shot to death over a 3-month period. Scene and autopsy findings, including the unusual finding of postmortem enucleation of the eyes, led investigators to recognize the serial nature of the homicides.
Chlordiazepoxide and diazepam induced mouse killing by rats.
Leaf, R C; Wnek, D J; Gay, P E; Corcia, R M; Lamon, S
1975-10-14
Chlordiazepoxide HCl, at dose levels from 2.5 mg/kg to 80 mg/kg, significantly increased the low base rates of mouse killing (3-9%) observed in large samples (N = 100/dose) of Holtzman strain albino male rats. Maximal killing rates were obtained at doses from 7.5 mg/kg to 20 mg/kg. Diazepam was equally effective, and several times more potent than chlordiazepoxide. Pentobarbital did not increase killing. Killing induced by chlordiazepoxide was blocked by d-amphetamine SO4, but not by l-amphetamine, at dose levels similar to those that block undrugged killing in this strain (ED50 = 1.5 mg/kg). Unlike pilocarpine-induced killing, the effects of chlordiazepoxide were not increased or decreased significantly by either peripherally or centrally active anticholinergic drugs, over wide dose ranges of these agents; nor were the effects of chlordiazepoxide increased by repeated daily administration.
Killing, letting die and moral perception.
Gillett, Grant
1994-10-01
There are a number of arguments that purport to show, in general terms, that there is no difference between killing and letting die. These are used to justify active euthanasia on the basis of the reasons given for allowing patients to die. I argue that the general and abstract arguments fail to take account of the complex and particular situations which are found in the care of those with terminal illness. When in such situations, there are perceptions and intuitions available that do not easily find propositional form but lead most of those whose practice is in the care of the dying to resist active euthanasia. I make a plea for their intuitions to be heeded above the sterile voice of abstract premises and arguments by examining the completeness of the outline form of the pro-euthanasia argument. In doing so, I make use of Nussbaum's discussion of moral perception and general claims to be found in the literature of moral particularism.
Killing Symmetries in $\\mathcal{H}$-Spaces with $\\Lambda$
Chudecki, Adam
2013-01-01
All Killing symmetries in complex $\\mathcal{H}$-spaces with $\\Lambda$ in terms of the Pleba\\'nski - Robinson - Finley coordinate system are found. All $\\mathcal{H}$-metrics with $\\Lambda$ admitting a null Killing vector are explicitly given. It is shown that the problem of non-null Killing vector reduces to looking for solution of the Boyer - Finley - Pleba\\'nski (Toda field) equation
The geometry of D=11 null killing spinors
Energy Technology Data Exchange (ETDEWEB)
Gauntlett, Jerome P.; Gutowski, Jan B. E-mail: gutowski@maths.ox.ac.uk; Stathis Pakis
2003-12-01
We determine the necessary and sufficient conditions on the metric and the four-form for the most general bosonic supersymmetric configurations of D=11 supergravity which admit a null Killing spinor i.e. a Killing spinor which can be used to construct a null Killing vector. This class covers all supersymmetric time-dependent configurations and completes the classification of the most general supersymmetric configurations initiated in hep-th/0212008. (author)
The Geometry of D=11 Null Killing Spinors
Gauntlett, J P; Pakis, S
2003-01-01
We determine the necessary and sufficient conditions on the metric and the four-form for the most general bosonic supersymmetric configurations of D=11 supergravity which admit a null Killing spinor i.e. a Killing spinor which can be used to construct a null Killing vector. This class covers all supersymmetric time-dependent configurations and completes the classification of the most general supersymmetric configurations initiated in hep-th/0212008.
Comparative sero evaluation of live and killed Gumboro vaccine in broilers.
Directory of Open Access Journals (Sweden)
Mohammed Taimur
2010-01-01
Full Text Available Infectious Bursal Disease (IBD is a fatal disease, which is caused by a Birna virus. Vaccination is one of the most effectiveways to prevent virus. Two types of vaccines (live and killed are normally used to induce immunity. In the presentexperiment, comparative sero evaluation of live and killed Gumboro vaccine in broilers was carried out. For comparingthe titers obtained with the two vaccines, one broiler group was vaccinated with live and the other with killed vaccine. Atfour points in time serum was collected from these broilers. Serum samples were collected on day 0 and day 14 of age(i.e. before vaccination was administered at 14 days of age and subsequently on day 28 and day 42 (i.e. 14 and 28 daysafter vaccination. Collected serum samples were examined to determine antibody titer using the indirect ELISA method.The average maternal antibody titers were 2888.80 and 224.80 on day 0 and day 14 of age, respectively. The averagecombined titer of killed vaccine was 3582.1 on day 28 and day 42 and the average combined titer of live vaccine was1513 on days 28 and 42. The efficacy of killed vaccine was higher than that of live vaccine. It was observed that live vaccineinduced the desired immunity for a limited period of time. Higher antibody titers were obtained from killed vaccineafter live vaccine administration. For these reasons, it is suggested to administer live vaccine first and subsequently thekilled vaccine in order to obtain an immediate immune response and subsequently to maintain high antibody titers for along period.
Fourth Thematic CERN School of Computing
Alberto Pace, CSC Director
2016-01-01
The Fourth Thematic School of Computing (tCSC2016) takes place this year in Split, Croatia, from 22 to 28 May 2016. The theme is "Efficient and Parallel Processing of Scientific Data", looking at: The challenge of scientific data processing: commonalities, analogies and the main differences between different sciences. Size of scientific software projects. Parallelism and asynchronism: computation and I/O. The School is open to postgraduate students and research workers with a few years' experience in elementary particle physics, computing, engineering or related fields. All applicants are welcome, including former and future participants in the main CSC summer school. Registration will close on 15 February and participation is limited to 24 students. To register, please go here. About: The Thematic Schools are part of the annual series of CERN Schools of Computing, to promote advanced learning and knowledge exchange on the subject of scientific compu...
Fourth International Conference on Complex Systems
Minai, Ali A; Unifying Themes in Complex Systems IV
2008-01-01
In June of 2002, over 500 professors, students and researchers met in Boston, Massachusetts for the Fourth International Conference on Complex Systems. The attendees represented a remarkably diverse collection of fields: biology, ecology, physics, engineering, computer science, economics, psychology and sociology, The goal of the conference was to encourage cross-fertilization between the many disciplines represented and to deepen understanding of the properties common to all complex systems. This volume contains 43 papers selected from the more than 200 presented at the conference. Topics include: cellular automata, neurology, evolution, computer science, network dynamics, and urban planning. About NECSI: For over 10 years, The New England Complex Systems Institute (NECSI) has been instrumental in the development of complex systems science and its applications. NECSI conducts research, education, knowledge dissemination, and community development around the world for the promotion of the study of complex sys...
Fourth-generation Mars vehicle concepts
Sherwood, Brent
1994-09-01
Conceptual designs for fourth-generation crew-carrying Mars transfer and excursion vehicles, fully integrated to state-of-the-art standards, are presented. The resulting vehicle concepts are sized for six crew members, and can support all opposition and conjunction opportunities in or after 2014. The modular, reusable transfer ship is launched to Earth orbit on six 185-ton-class boosters and assembled there robotically. Its dual nuclear-thermal rocket engines use liquid hydrogen propollant. The payload consists of a microgravity habitation system and an expendable lift-to-drag = 1.6 lander capable of aeromaneuvering to sites within +/- 20 deg of the equator. This lander can deliver either an expendable, storable-bipropellant crew-carrying ascent vehicle, or 40 tons of cargo, and it is capable of limited surface mobility to support base buildup. Multiple cargo landers sent ahead on robotic transfer vehicles deliver the supplies and equipment required for long-duration surface missions.
Fourth ventricle meningiomas: a rare entity.
Pichierri, Angelo; Ruggeri, Andrea; Morselli, Carlotta; Delfini, Roberto
2011-08-01
Fourth ventricle meningiomas (FVMs) are rare, often misdiagnosed, lesions. To the best of our knowledge, 47 cases have been reported in the literature: we describe our series of three cases treated at our Institution, focusing on some diagnostic tips and intraoperative features of these tumours. Our three patients have a history of headache. Gait disturbances, vomiting and/or diplopia complicated the clinical picture before the referral at our Department. The operations were uneventful, and the patients fully recovered from neurological symptoms. They are free of recurrence at a median follow-up of 19 years. FVMs are rare lesions, which are difficult to differentiate preoperatively from the much more common ependymomas. A preoperative distinction would be extremely advantageous: indeed, although both tumours share similar radiological and clinical patterns, they clearly differ as to surgical difficulty and outcome. In fact, meningiomas are comparatively easier to remove, granting better clinical results.
Fourth World Theory: The Evolution of . . .
Directory of Open Access Journals (Sweden)
Olon F. Dotson
2014-05-01
Full Text Available Fourth World theory is a methodology for examining and developing greater understanding of the extent of the distress and abandonment commonly found in the cores of American cities resulting from de-industrialization, historic segregation and discrimination patterns, suburban sprawl, erosion of a viable tax base, racism, inability to embrace the concept of desegregation and civil rights legislation, fear, despair, crumbling infrastructure systems, disinvestment in urban school systems, and environmental justice issues. This article uses the analytical lens of Fourth World theory to examine how such structural and cultural forces contributed to the severely distressed conditions now found in the city of Gary, Indiana. Tracking its one-hundred-year history, from its founding as an industrial town through its post-industrial decline occurring during the city’s first African-American mayor’s five terms in office, the methodology clearly demonstrates how the social construction of race has systematically undermined every aspect of Gary’s overall quality of life. To illustrate that this city is not an anomaly but rather reflects a typical pattern of disparity and uneven development arising from racist practices, Gary is compared to other cities of similar size and also to the much larger Detroit. The article triangulates academic literature, news media archives, and an oral history provided by the mayor to show how Gary evolved from being a model industrial city to a cauldron of racial disparity. The paper concludes by arguing that continued absence of reflection on the nation’s historical racialization of place threatens not just impoverished communities of color, but also the sustainability of the entire nation.
Antibacterial activity of silver-killed bacteria: the "zombies" effect
Wakshlak, Racheli Ben-Knaz; Pedahzur, Rami; Avnir, David
2015-04-01
We report a previously unrecognized mechanism for the prolonged action of biocidal agents, which we denote as the zombies effect: biocidally-killed bacteria are capable of killing living bacteria. The concept is demonstrated by first killing Pseudomonas aeruginosa PAO1 with silver nitrate and then challenging, with the dead bacteria, a viable culture of the same bacterium: Efficient antibacterial activity of the killed bacteria is observed. A mechanism is suggested in terms of the action of the dead bacteria as a reservoir of silver, which, due to Le-Chatelier's principle, is re-targeted to the living bacteria. Langmuirian behavior, as well as deviations from it, support the proposed mechanism.
Directory of Open Access Journals (Sweden)
Susana Rostro-García
Full Text Available Understanding how animals utilize available space is important for their conservation, as it provides insight into the ecological needs of the species, including those related to habitat, prey and inter and intraspecific interactions. We used 28 months of radio telemetry data and information from 200 kill locations to assess habitat selection at the 3rd order (selection of habitats within home ranges and 4th order (selection of kill sites within the habitats used of a reintroduced population of cheetahs Acinonyx jubatus in Phinda Private Game Reserve, South Africa. Along with landscape characteristics, we investigated if lion Panthera leo presence affected habitat selection of cheetahs. Our results indicated that cheetah habitat selection was driven by a trade-off between resource acquisition and lion avoidance, and the balance of this trade-off varied with scale: more open habitats with high prey densities were positively selected within home ranges, whereas more closed habitats with low prey densities were positively selected for kill sites. We also showed that habitat selection, feeding ecology, and avoidance of lions differed depending on the sex and reproductive status of cheetahs. The results highlight the importance of scale when investigating a species' habitat selection. We conclude that the adaptability of cheetahs, together with the habitat heterogeneity found within Phinda, explained their success in this small fenced reserve. The results provide information for the conservation and management of this threatened species, especially with regards to reintroduction efforts in South Africa.
Rostro-García, Susana; Kamler, Jan F.; Hunter, Luke T. B.
2015-01-01
Understanding how animals utilize available space is important for their conservation, as it provides insight into the ecological needs of the species, including those related to habitat, prey and inter and intraspecific interactions. We used 28 months of radio telemetry data and information from 200 kill locations to assess habitat selection at the 3rd order (selection of habitats within home ranges) and 4th order (selection of kill sites within the habitats used) of a reintroduced population of cheetahs Acinonyx jubatus in Phinda Private Game Reserve, South Africa. Along with landscape characteristics, we investigated if lion Panthera leo presence affected habitat selection of cheetahs. Our results indicated that cheetah habitat selection was driven by a trade-off between resource acquisition and lion avoidance, and the balance of this trade-off varied with scale: more open habitats with high prey densities were positively selected within home ranges, whereas more closed habitats with low prey densities were positively selected for kill sites. We also showed that habitat selection, feeding ecology, and avoidance of lions differed depending on the sex and reproductive status of cheetahs. The results highlight the importance of scale when investigating a species’ habitat selection. We conclude that the adaptability of cheetahs, together with the habitat heterogeneity found within Phinda, explained their success in this small fenced reserve. The results provide information for the conservation and management of this threatened species, especially with regards to reintroduction efforts in South Africa. PMID:25693067
Rostro-García, Susana; Kamler, Jan F; Hunter, Luke T B
2015-01-01
Understanding how animals utilize available space is important for their conservation, as it provides insight into the ecological needs of the species, including those related to habitat, prey and inter and intraspecific interactions. We used 28 months of radio telemetry data and information from 200 kill locations to assess habitat selection at the 3rd order (selection of habitats within home ranges) and 4th order (selection of kill sites within the habitats used) of a reintroduced population of cheetahs Acinonyx jubatus in Phinda Private Game Reserve, South Africa. Along with landscape characteristics, we investigated if lion Panthera leo presence affected habitat selection of cheetahs. Our results indicated that cheetah habitat selection was driven by a trade-off between resource acquisition and lion avoidance, and the balance of this trade-off varied with scale: more open habitats with high prey densities were positively selected within home ranges, whereas more closed habitats with low prey densities were positively selected for kill sites. We also showed that habitat selection, feeding ecology, and avoidance of lions differed depending on the sex and reproductive status of cheetahs. The results highlight the importance of scale when investigating a species' habitat selection. We conclude that the adaptability of cheetahs, together with the habitat heterogeneity found within Phinda, explained their success in this small fenced reserve. The results provide information for the conservation and management of this threatened species, especially with regards to reintroduction efforts in South Africa.
Is there a moral difference between killing and letting die in healthcare?
Directory of Open Access Journals (Sweden)
Mohammed Ratoubi Alanazi
2015-01-01
Full Text Available The purpose of this review is to prove that there is no moral difference between killing and letting one die in healthcare. It is important to be aware of the moral equivalence of killing and letting die. The doctor that allows the patient to die without providing life saving measures, and the doctor that administers a lethal injection both have the same outcome. The patient dies in either case. The Abrahamic religions; Islam, Christianity, and Judaism, all argue for the sanctity of life. The world's major religions; Islam, Christianity, and Judaism all have doctrines concerning the sanctity of life; and they support the main arguments of this study that there is no moral difference between killing and letting die. In relation to patient autonomy and the patients right to die, it is very important to highlight that doctors have a moral and legal responsibility to save lives. In addition, we discuss the distinction centres on the true definition of patient autonomy, and who is responsible for defining the and ldquo;quality and rdquo; of life. The intention and foresight are critical points that support the thesis statement that killing and letting one die are one in the same. Intention is the intentional killing of a human being, however, the when one refers to foreseen, it brings to mind images of a doctor and a patient's family that is taking into consideration the entire different variables that they must deal with in order to decide whether or not to terminate life sustaining measures. They are trying to foresee what type of life the patient will have if life prolonging treatment is withdrawn. The acts and omissions doctrine as described in this review shows that there is no moral difference to kill a person or to let him die. The end result is the same, and someone is dead. Finally, we extensively discussed the various viewpoints regarding whether or not there is a moral difference between killing and letting die. The evidence reveals that
Investigating CTL mediated killing with a 3D cellular automaton.
Directory of Open Access Journals (Sweden)
Frederik Graw
2009-08-01
Full Text Available Cytotoxic T lymphocytes (CTLs are important immune effectors against intra-cellular pathogens. These cells search for infected cells and kill them. Recently developed experimental methods in combination with mathematical models allow for the quantification of the efficacy of CTL killing in vivo and, hence, for the estimation of parameters that characterize the effect of CTL killing on the target cell populations. It is not known how these population-level parameters relate to single-cell properties. To address this question, we developed a three-dimensional cellular automaton model of the region of the spleen where CTL killing takes place. The cellular automaton model describes the movement of different cell populations and their interactions. Cell movement patterns in our cellular automaton model agree with observations from two-photon microscopy. We find that, despite the strong spatial nature of the kinetics in our cellular automaton model, the killing of target cells by CTLs can be described by a term which is linear in the target cell frequency and saturates with respect to the CTL levels. Further, we find that the parameters describing CTL killing on the population level are most strongly impacted by the time a CTL needs to kill a target cell. This suggests that the killing of target cells, rather than their localization, is the limiting step in CTL killing dynamics given reasonable frequencies of CTL. Our analysis identifies additional experimental directions which are of particular importance to interpret estimates of killing rates and could advance our quantitative understanding of CTL killing.
Searching for the fourth family quarks through anomalous decays
Sahin, M.; Sultansoy, S.; Turkoz, S.
2010-09-01
The flavor democracy hypothesis predicts the existence of the fourth standard model family. Because of the high masses of the fourth family quarks, their anomalous decays could be dominant if certain criteria are met. This will drastically change the search strategy at hadron colliders. We show that the fourth standard model family down quarks with masses up to 400-450 GeV can be observed (or excluded) via anomalous decays by Tevatron.
The Fourth Gospel as a textual field of meaning
Micallef, Martin
2014-01-01
The Fourth Gospel is a textual field of meaning and it reinforces pressure on readers to differentiate appearance from intended meaning. No single interpretation can claim to have said the last word on the meaning of the Fourth Gospel’s use of language, which may be considered as the most striking characteristic of this Gospel. The whole network of the Johannine literary devices and vocabulary is an expression of the Fourth Gospel’s theological message and brings dissimilari...
Targeted Killing: Self-Defense, Preemption, and the War on Terrorism
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Thomas Byron Hunter
2009-01-01
Full Text Available This paper assesses the parameters and utility of “targeted killing” in combating terrorism and its role within the norm of state self-defense in the international community. The author’s thesis is that, while targeted killing provides states with a method of combating terrorism, and while it is “effective” on a number of levels, it is inherently limited and not a panacea. The adoption and execution of such a program brings with it, among other potential pitfalls, political repercussions.Targeted killing is defined herein as the premeditated, preemptive, and intentional killing of an individual or individuals known or believed to represent a present and/or future threat to the safety and security of a state through affiliation with terrorist groups or individuals.The principal conclusions of this paper are that targeted killing:● Must be wholly differentiated from “assassination” and relatedoperations involving the intentional targeting of an individual during wartime, in order to be considered properly and rationally.● Is a politically risky undertaking with potentially negative international implications.● Is the proven desire of some terrorist groups to conduct attacks involving mass casualties against innocent civilians that may, in the future, cause states to reconsider previous abstention from adopting targeted killing in order to protect their populace.● Can serve to impact terrorists and terrorist groups on a strategic,operational, and tactical level.● Has historically had both negative and (unintentionally positiveimpacts for terrorist groups.● Oftentimes exposes civilians to unintentional harm.The methods of investigation include a thorough review of the available literature: books, published and unpublished essays, interviews of 2 selected individuals (to include academics and retired members of military and police forces, and the author’s independent analysis.
Control of Influenza and Poliomyelitis with Killed Virus Vaccines
Salk, Jonas; Salk, Darrell
1977-01-01
Discusses control of poliomyelitis and influenza by live and killed virus vaccines. Considered are the etiological agents, pathogenic mechanisms and epidemiology of each disease. Reviews recent scientific studies of the diseases. Recommends use of killed virus vaccines in controlling both diseases. (CS)
Defective phagocyte Aspergillus killing associated with recurrent pulmonary Aspergillus infections.
Fietta, A; Sacchi, F; Mangiarotti, P; Manara, G; Gialdroni Grassi, G
1984-01-01
An apparently healthy boy was suffering from recurrent Aspergillus infections. No classical conditions of immunodeficiency were found. Studies on the patient's phagocytic system revealed neutrophils and monocytes to function normally except in Aspergillus killing (microbicidal activity for bacteria and Candida was normal). Aspergillus killing mechanisms may be complex and peculiarly selective, possibly involving both oxygen-dependent and independent mechanisms.
Beneath the surface: killing of fish as a moral problem
Bovenkerk, B.; Braithwaite, V.A.
2016-01-01
Are we morally justified in killing fish and if so, for what purposes? We do not focus on the suffering that is done during the killing, but on the question whether death itself is harmful for fish. We need to distinguish two questions; first, can death be considered a harm for fish? And second, if
9 CFR 113.210 - Feline Calicivirus Vaccine, Killed Virus.
2010-01-01
... Virus. 113.210 Section 113.210 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE VIRUSES, SERUMS, TOXINS, AND ANALOGOUS PRODUCTS; ORGANISMS AND VECTORS STANDARD REQUIREMENTS Killed Virus Vaccines § 113.210 Feline Calicivirus Vaccine, Killed Virus. Feline Calicivirus...
Killing day-old chicks? Public opinion regarding potential alternatives
Leenstra, F.; Munnichs, G.M.; Beekman, V.; Vromans, E.; Aramyan, L.; Woelders, H.
2011-01-01
Throughout the world, male chicks from layer breeds are killed just after hatching, as they are not profitable as regards the production of meat. The Dutch and European parliaments have insisted on research into possible alternatives to the killing of day-old chicks. In the present study we have inv
9 CFR 113.211 - Feline Rhinotracheitis Vaccine, Killed Virus.
2010-01-01
... Rhinotracheitis Vaccine, Killed Virus, shall be prepared from virus-bearing cell culture fluids. Only Master Seed... and individually tested on susceptible cell cultures for the presence of feline rhinotracheitis virus... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Feline Rhinotracheitis Vaccine, Killed...
9 CFR 113.216 - Bovine Rhinotracheitis Vaccine, Killed Virus.
2010-01-01
... Virus. 113.216 Section 113.216 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE VIRUSES, SERUMS, TOXINS, AND ANALOGOUS PRODUCTS; ORGANISMS AND VECTORS STANDARD REQUIREMENTS Killed Virus Vaccines § 113.216 Bovine Rhinotracheitis Vaccine, Killed Virus. Infectious...
Killing (absorption) versus survival in random motion
Garbaczewski, Piotr
2017-09-01
We address diffusion processes in a bounded domain, while focusing on somewhat unexplored affinities between the presence of absorbing and/or inaccessible boundaries. For the Brownian motion (Lévy-stable cases are briefly mentioned) model-independent features are established of the dynamical law that underlies the short-time behavior of these random paths, whose overall lifetime is predefined to be long. As a by-product, the limiting regime of a permanent trapping in a domain is obtained. We demonstrate that the adopted conditioning method, involving the so-called Bernstein transition function, works properly also in an unbounded domain, for stochastic processes with killing (Feynman-Kac kernels play the role of transition densities), provided the spectrum of the related semigroup operator is discrete. The method is shown to be useful in the case, when the spectrum of the generator goes down to zero and no isolated minimal (ground state) eigenvalue is in existence, like in the problem of the long-term survival on a half-line with a sink at origin.
Combinatorial stresses kill pathogenic Candida species.
Kaloriti, Despoina; Tillmann, Anna; Cook, Emily; Jacobsen, Mette; You, Tao; Lenardon, Megan; Ames, Lauren; Barahona, Mauricio; Chandrasekaran, Komelapriya; Coghill, George; Goodman, Daniel; Gow, Neil A R; Grebogi, Celso; Ho, Hsueh-Lui; Ingram, Piers; McDonagh, Andrew; de Moura, Alessandro P S; Pang, Wei; Puttnam, Melanie; Radmaneshfar, Elahe; Romano, Maria Carmen; Silk, Daniel; Stark, Jaroslav; Stumpf, Michael; Thiel, Marco; Thorne, Thomas; Usher, Jane; Yin, Zhikang; Haynes, Ken; Brown, Alistair J P
2012-10-01
Pathogenic microbes exist in dynamic niches and have evolved robust adaptive responses to promote survival in their hosts. The major fungal pathogens of humans, Candida albicans and Candida glabrata, are exposed to a range of environmental stresses in their hosts including osmotic, oxidative and nitrosative stresses. Significant efforts have been devoted to the characterization of the adaptive responses to each of these stresses. In the wild, cells are frequently exposed simultaneously to combinations of these stresses and yet the effects of such combinatorial stresses have not been explored. We have developed a common experimental platform to facilitate the comparison of combinatorial stress responses in C. glabrata and C. albicans. This platform is based on the growth of cells in buffered rich medium at 30°C, and was used to define relatively low, medium and high doses of osmotic (NaCl), oxidative (H(2)O(2)) and nitrosative stresses (e.g., dipropylenetriamine (DPTA)-NONOate). The effects of combinatorial stresses were compared with the corresponding individual stresses under these growth conditions. We show for the first time that certain combinations of combinatorial stress are especially potent in terms of their ability to kill C. albicans and C. glabrata and/or inhibit their growth. This was the case for combinations of osmotic plus oxidative stress and for oxidative plus nitrosative stress. We predict that combinatorial stresses may be highly significant in host defences against these pathogenic yeasts.
Novel innate cancer killing activity in humans
Directory of Open Access Journals (Sweden)
Lovato James
2011-08-01
Full Text Available Abstract Background In this study, we pilot tested an in vitro assay of cancer killing activity (CKA in circulating leukocytes of 22 cancer cases and 25 healthy controls. Methods Using a human cervical cancer cell line, HeLa, as target cells, we compared the CKA in circulating leukocytes, as effector cells, of cancer cases and controls. The CKA was normalized as percentages of total target cells during selected periods of incubation time and at selected effector/target cell ratios in comparison to no-effector-cell controls. Results Our results showed that CKA similar to that of our previous study of SR/CR mice was present in human circulating leukocytes but at profoundly different levels in individuals. Overall, males have a significantly higher CKA than females. The CKA levels in cancer cases were lower than that in healthy controls (mean ± SD: 36.97 ± 21.39 vs. 46.28 ± 27.22. Below-median CKA was significantly associated with case status (odds ratio = 4.36; 95% Confidence Interval = 1.06, 17.88 after adjustment of gender and race. Conclusions In freshly isolated human leukocytes, we were able to detect an apparent CKA in a similar manner to that of cancer-resistant SR/CR mice. The finding of CKA at lower levels in cancer patients suggests the possibility that it may be of a consequence of genetic, physiological, or pathological conditions, pending future studies with larger sample size.
The Fourth World Conference on Women.
1995-01-01
The Fourth World Conference on Women held in Beijing during September 4-15, 1995, was a major success. The platform for action adopted by consensus at the conference is comprised of the mission statement, a global framework, critical areas of concern, strategic objectives and actions, and institutional and financial arrangements. The conference was an extension of other large international conferences organized under UN initiative over the past 15 years. The Beijing platform of action aims to remove all obstacles to women's active participation in all spheres of public and private life through a full and equal share in economic, social, cultural, and political decision-making. The following concerns were defined by the conference: eradicating poverty, increasing school enrollment and eliminating gender inequalities in access to education, improving access to health care and eliminating gender inequalities in access to services, eliminating violence against women, mitigating the consequences of armed conflicts against women, securing equal access of men and women to economic resources and employment, providing equal participation of men and women in power structures and decision making, enhancing national mechanisms to promote the advancement of women, protecting the rights of girls and women, eradicating stereotypes about women, participating in the management of natural resources and environmental protection, and improving the status of girls.
Mandibular asymmetry and the fourth dimension.
Kaban, Leonard B
2009-03-01
This paper represents more than 30 years of discussion and collaboration with Drs Joseph Murray and John Mulliken in an attempt to understand growth patterns over time (ie, fourth dimension) in patients with hemifacial microsomia (HFM). This is essential for the development of rational treatment protocols for children and adults with jaw asymmetry. Traditionally, HFM was thought of as a unilateral deformity, but it was recognized that 20% to 30% of patients had bilateral abnormalities. However, early descriptions of skeletal correction addressed almost exclusively lengthening of the short (affected) side of the face. Based on longitudinal clinical observations of unoperated HFM patients, we hypothesized that abnormal mandibular growth is the earliest skeletal manifestation and that restricted growth of the mandible plays a pivotal role in progressive distortion of both the ipsilateral and contralateral facial skeleton. This hypothesis explains the progressive nature of the asymmetry in patients with HFM and provides the rationale for surgical lengthening of the mandible in children to prevent end-stage deformity. During the past 30 years, we have learned that this phenomenon of progressive distortion of the adjacent and contralateral facial skeleton occurs with other asymmetric mandibular undergrowth (tumor resection, radiation therapy, or posttraumatic defects) and overgrowth (mandibular condylar hyperplasia) conditions. In this paper, I describe the progression of deformity with time in patients with mandibular asymmetry as a result of undergrowth and overgrowth. Understanding these concepts is critical for the development of rational treatment protocols for adults with end-stage asymmetry and for children to minimize secondary deformity.
Neural crest: The fourth germ layer
Directory of Open Access Journals (Sweden)
K Shyamala
2015-01-01
Full Text Available The neural crest cells (NCCs, a transient group of cells that emerges from the dorsal aspect of the neural tube during early vertebrate development has been a fascinating group of cells because of its multipotency, long range migration through embryo and its capacity to generate a prodigious number of differentiated cell types. For these reasons, although derived from the ectoderm, the neural crest (NC has been called the fourth germ layer. The non neural ectoderm, the neural plate and the underlying mesoderm are needed for the induction and formation of NC cells. Once formed, NC cells start migrating as a wave of cells, moving away from the neuroepithelium and quickly splitting into distinct streams. These migrating NCCs home in to different regions and give rise to plethora of tissues. Umpteen number of signaling molecules are essential for formation, epithelial mesenchymal transition, delamination, migration and localization of NCC. Authors believe that a clear understanding of steps and signals involved in NC formation, migration, etc., may help in understanding the pathogenesis behind cancer metastasis and many other diseases. Hence, we have taken this review to discuss the various aspects of the NC cells.
A New Holographic Entropy Bound from Conformal Field Theory at the Killing Horizon
Institute of Scientific and Technical Information of China (English)
荆继良
2002-01-01
A new holographic entropy bound is obtained by using conformal field theory at the Killing horizon. The entropy bound is tighter than the well-known bounds, such as the Bekenstein, Bekenstein-Mayo and 't Hooft bounds. The result shows that the entropy of a system decreases when quantum effects are included. Therefore, the quantum effect will increase the degree of order of the system.
Kathman, Jacob D.; Wood, Reed M.
2011-01-01
How do third-party interventions affect the severity of mass killings? The authors theorize that episodes of mass killing are the consequence of two factors: (1) the threat perceptions of the perpetrators and (2) the cost of implementing genocidal policies relative to other alternatives. To reduce genocidal hostilities, interveners must address…
Field-Based Concerns about Fourth-Generation Evaluation Theory.
Lai, Morris K.
Some aspects of fourth generation evaluation procedures that have been advocated by E. G. Guba and Y. S. Lincoln were examined empirically, with emphasis on areas where there have been discrepancies between theory and field-based experience. In fourth generation evaluation, the product of an evaluation is not a set of conclusions, recommendations,…
Human Resources Administration: A School-Based Perspective. Fourth Edition
Smith, Richard
2009-01-01
Enhanced and updated, this Fourth Edition of Richard E. Smith's highly successful text examines the growing role of the principal in planning, hiring, staff development, supervision, and other human resource functions. The Fourth Edition includes new sections on ethics, induction, and the role of the mentor teacher. This edition also introduces…
Human Resources Administration: A School-Based Perspective. Fourth Edition
Smith, Richard
2009-01-01
Enhanced and updated, this Fourth Edition of Richard E. Smith's highly successful text examines the growing role of the principal in planning, hiring, staff development, supervision, and other human resource functions. The Fourth Edition includes new sections on ethics, induction, and the role of the mentor teacher. This edition also introduces…
Psychological traits underlying different killing methods among Malaysian male murderers.
Kamaluddin, Mohammad Rahim; Shariff, Nadiah Syariani; Nurfarliza, Siti; Othman, Azizah; Ismail, Khaidzir H; Mat Saat, Geshina Ayu
2014-04-01
Murder is the most notorious crime that violates religious, social and cultural norms. Examining the types and number of different killing methods that used are pivotal in a murder case. However, the psychological traits underlying specific and multiple killing methods are still understudied. The present study attempts to fill this gap in knowledge by identifying the underlying psychological traits of different killing methods among Malaysian murderers. The study adapted an observational cross-sectional methodology using a guided self-administered questionnaire for data collection. The sampling frame consisted of 71 Malaysian male murderers from 11 Malaysian prisons who were selected using purposive sampling method. The participants were also asked to provide the types and number of different killing methods used to kill their respective victims. An independent sample t-test was performed to establish the mean score difference of psychological traits between the murderers who used single and multiple types of killing methods. Kruskal-Wallis tests were carried out to ascertain the psychological trait differences between specific types of killing methods. The results suggest that specific psychological traits underlie the type and number of different killing methods used during murder. The majority (88.7%) of murderers used a single method of killing. Multiple methods of killing was evident in 'premeditated' murder compared to 'passion' murder, and revenge was a common motive. Examples of multiple methods are combinations of stabbing and strangulation or slashing and physical force. An exception was premeditated murder committed with shooting, when it was usually a single method, attributed to the high lethality of firearms. Shooting was also notable when the motive was financial gain or related to drug dealing. Murderers who used multiple killing methods were more aggressive and sadistic than those who used a single killing method. Those who used multiple methods or
An isolated fourth ventricle in neurosarcoidosis: MRI findings
Energy Technology Data Exchange (ETDEWEB)
Hesselmann, Volker; Terstegge, Klaus; Schulte, Oliver; Krug, Barbara; Lackner, Klaus [Department of Radiology, University of Cologne, Joseph Stelzmann Strasse 9, 50924 Cologne (Germany); Wedekind, Christoph [Department of Neurosurgery, University of Cologne, Joseph Stelzmann Strasse 9, 50924 Cologne (Germany); Voges, Juergen [Department of Stereotaxy und Functional Neurosurgery, University of Cologne, Joseph Stelzmann Strasse 9, 50924 Cologne (Germany)
2002-07-01
We report on an isolated enlargement of the fourth ventricle in a patient with neurosarcoidosis which developed 3 years after the insertion of a ventriculo-atrial shunt. Repeated MRI images were obtained in a patient with known neurosarcoidosis between 1995 and 2000. Imaging findings were correlated to the medical course of the patient, who developed a hydrocephalus and a trapped fourth ventricle consecutively. The isolation was presumably due to granulomatous inflammation of the ependyma surrounding the fourth ventricular outlets. The isolated fourth ventricle was responsible for a deterioration of neurological status. Neurosarcoidosis is a severe complication in sarcoidosis patients. An isolated enlargement of the fourth ventricle is a rare complication in clinically deteriorated patients with neurosarcoidosis and ventricular drainage, which may require neurosurgical treatment. (orig.)
Syringomyelia regression after shunting of a trapped fourth ventricle
Directory of Open Access Journals (Sweden)
Dukagjin Morina
2013-01-01
Full Text Available We describe a case of progressive syringomyelia following post-infectious trapped fourth ventricle (TFV, which resolved after shunting of the fourth ventricle. A 28-year-old female who had previously undergone treatment of intracerebral hemorrhage and meningitis developed a hydrocephalus with TFV. After 3 years she developed disturbance of walking and coordination. Cranial-CT revealed an enlargement of the shunted fourth ventricle as a result of shunt dysfunction. Furthermore a cervical syringomyelia developed. The patient underwent a revision of a failed fourth ventriculo- peritoneal shunt. Postoperatively, syringomyelia resolved within 6 months and the associated neurological deficits improved significantly. An insufficiency of cerebrospinal fluid draining among patients with TFV can be associated with communicating syringomyelia. An early detection and treatment seems important on resolving syringomyelia and avoiding permanent neurological deficits. Ventriculo-peritoneal shunt in trapped fourth ventricles can resolve a secondary syringomyelia.
Proceedings: Fourth Workshop on Mining Scientific Datasets
Energy Technology Data Exchange (ETDEWEB)
Kamath, C
2001-07-24
Commercial applications of data mining in areas such as e-commerce, market-basket analysis, text-mining, and web-mining have taken on a central focus in the JCDD community. However, there is a significant amount of innovative data mining work taking place in the context of scientific and engineering applications that is not well represented in the mainstream KDD conferences. For example, scientific data mining techniques are being developed and applied to diverse fields such as remote sensing, physics, chemistry, biology, astronomy, structural mechanics, computational fluid dynamics etc. In these areas, data mining frequently complements and enhances existing analysis methods based on statistics, exploratory data analysis, and domain-specific approaches. On the surface, it may appear that data from one scientific field, say genomics, is very different from another field, such as physics. However, despite their diversity, there is much that is common across the mining of scientific and engineering data. For example, techniques used to identify objects in images are very similar, regardless of whether the images came from a remote sensing application, a physics experiment, an astronomy observation, or a medical study. Further, with data mining being applied to new types of data, such as mesh data from scientific simulations, there is the opportunity to apply and extend data mining to new scientific domains. This one-day workshop brings together data miners analyzing science data and scientists from diverse fields to share their experiences, learn how techniques developed in one field can be applied in another, and better understand some of the newer techniques being developed in the KDD community. This is the fourth workshop on the topic of Mining Scientific Data sets; for information on earlier workshops, see http://www.ahpcrc.org/conferences/. This workshop continues the tradition of addressing challenging problems in a field where the diversity of applications is
Laser Microbial Killing and Biofilm Disruption
Krespi, Yosef P.; Kizhner, Victor
2009-06-01
Objectives: To analyze the ability of NIR lasers to reduce bacterial load and demonstrate the capability of fiber-based Q-switched Nd:YAG laser disrupting biofilm. Study Design: NIR diode laser was tested in vitro and in vivo using pathogenic microorganisms (S. aureus, S. pneumoniae, P. aeruginosa). In addition biofilms were grown from clinical Pseudomonas isolates and placed in culture plates, screws, tympanostomy tubes and PET sutures. Methods: In the animal experiments acute rhinosinusitis model was created by packing the rabbit nose with bacteria soaked solution. The nasal pack was removed in two days and nose was exposed to laser irradiation. A 940 nm diode laser with fiber diffuser was used. Nasal cultures were obtained before and after the laser treatments. Animals were sacrificed fifteen days following laser treatment and bacteriologic/histologic results analyzed. Q-switched Nd:YAG laser generated shockwave pulses were delivered on biofilm using special probes over culture plates, screws, tubes, and PET sutures for the biofilm experiments. Results: Average of two log bacteria reduction was achieved with NIR laser compared to controls. Histologic studies demonstrated preservation of tissue integrity without significant damage to mucosa. Biofilms were imaged before, during and after treatment using a confocal microscope. During laser-generated shockwave application, biofilm was initially seen to oscillate and eventually break off. Large and small pieces of biofilm were totally and instantly removed from the surface to which they were attached in seconds. Conclusions: Significant bacterial reduction was achieved with NIR laser therapy in this experimental in vitro and animal study. In addition we disrupted Pseudomonas aeruginosa biofilms using Q-switched Nd:YAG laser and special probes generating plasma and shockwave. This new and innovative method of bacteria killing and biofilm disruption without injuring host tissue may have clinical application in the
Did Vertigo Kill America's Forgotten Astronaut?
Bendrick, Gregg A.; Merlin, Peter W.
2007-01-01
On November 15, 1967, U.S. Air Force test pilot Major Michael J. Adams was killed while flying the X-15 rocket-propelled research vehicle in a parabolic spaceflight profile. This flight was part of a joint effort with NASA. An electrical short in one of the experiments aboard the vehicle caused electrical transients, resulting in excessive workload by the pilot. At altitude Major Adams inappropriately initiated a flat spin that led to a series of unusual aircraft attitudes upon atmospheric re-entry, ultimately causing structural failure of the airframe. Major Adams was known to experience vertigo (i.e. spatial disorientation) while flying the X-15, but all X-15 pilots most likely experienced vertigo (i.e. somatogravic, or "Pitch-Up", illusion) as a normal physiologic response to the accelerative forces involved. Major Adams probably experienced vertigo to a greater degree than did others, since prior aeromedical testing for astronaut selection at Brooks AFB revealed that he had an unusually high degree of labyrinthine sensitivity. Subsequent analysis reveals that after engine burnout, and through the zenith of the flight profile, he likely experienced the oculoagravic ("Elevator") illusion. Nonetheless, painstaking investigation after the mishap revealed that spatial disorientation (Type II, Recognized) was NOT the cause, but rather, a contributing factor. The cause was in fact the misinterpretation of a dual-use flight instrument (i.e. Loss of Mode Awareness), resulting in confusion between yaw and roll indications, with subsequent flight control input that was inappropriate. Because of the altitude achieved on this flight, Major Adams was awarded Astronaut wings posthumously. Understanding the potential for spatial disorientation, particularly the oculoagravic illusion, associated with parabolic spaceflight profiles, and understanding the importance of maintaining mode awareness in the context of automated cockpit design, are two lessons that have direct
Protein chlorination in neutrophil phagosomes and correlation with bacterial killing.
Green, Jessie N; Kettle, Anthony J; Winterbourn, Christine C
2014-12-01
Neutrophils ingest and kill bacteria within phagocytic vacuoles. We investigated where they produce hypochlorous acid (HOCl) following phagocytosis by measuring conversion of protein tyrosine residues to 3-chlorotyrosine. We also examined how varying chloride availability affects the relationship between HOCl formation in the phagosome and bacterial killing. Phagosomal proteins, isolated following ingestion of opsonized magnetic beads, contained 11.4 Cl-Tyr per thousand tyrosine residues. This was 12 times higher than the level in proteins from the rest of the neutrophil and ~6 times higher than previously recorded for protein from ingested bacteria. These results indicate that HOCl production is largely localized to the phagosomes and a substantial proportion reacts with phagosomal protein before reaching the microbe. This will in part detoxify the oxidant but should also form chloramines which could contribute to the killing mechanism. Neutrophils were either suspended in chloride-free gluconate buffer or pretreated with formyl-Met-Leu-Phe, a procedure that has been reported to deplete intracellular chloride. These treatments, alone or in combination, decreased both chlorination in phagosomes and killing of Staphylococcus aureus by up to 50%. There was a strong positive correlation between the two effects. Killing was predominantly oxidant and myeloperoxidase dependent (88% inhibition by diphenylene iodonium and 78% by azide). These results imply that lowering the chloride concentration limits HOCl production and oxidative killing. They support a role for HOCl generation, rather than an alternative myeloperoxidase activity, in the killing process.
Wiebke, Jonas; Pahl, Elke; Schwerdtfeger, Peter
2012-07-01
A simple and efficient internal-coordinate importance sampling protocol for the Monte Carlo computation of (up to fourth-order) virial coefficients ̅B(n) of atomic systems is proposed. The key feature is a multivariate sampling distribution that mimics the product structure of the dominating pairwise-additive parts of the ̅B(n). This scheme is shown to be competitive over routine numerical methods and, as a proof of principle, applied to neon: The second, third, and fourth virial coefficients of neon as well as equation-of-state data are computed from ab initio two- and three-body potentials; four-body contributions are found to be insignificant. Kirkwood-Wigner quantum corrections to first order are found to be crucial to the observed agreement with recent ab initio and experimental reference data sets but are likely inadequate at very low temperatures.
HIV transcription is induced with some forms of cell killing
Energy Technology Data Exchange (ETDEWEB)
Woloschak, G.E. [Argonne National Lab., IL (United States); Schreck, S. [Argonne National Lab., IL (United States)][South Carolina Univ., Columbia, SC (United States). Dept. of Chemistry; Panozzo, J. [Loyola Univ. Medical Center, Maywood, IL (United States); Chang-Liu, C.-M. [Argonne National Lab., IL (United States); Libertin, C.R. [Loyola Univ. Medical Center, Maywood, IL (United States)
1996-11-01
Using HeLa cells stably transfected with an HIV-LTR-CAT construct`, we demonstrated a peak in CAT induction that occurs in viable (but not necessarily cell-division-competent) cells 24 h following exposure to some cell-killing agents. {Gamma} rays were the only cell-killing agent which did not induce HIV transcription; this can be attributed to the fact that {gamma}-ray-induced apoptotic death requires function p53, which is missing in HeLa cells. For all other agents, HIV-LTR induction was dose-dependent and correlated with the amount of cell killing that occurred in the culture.
Factors Affecting Zebra Mussel Kill by the Bacterium Pseudomonas fluorescens
Energy Technology Data Exchange (ETDEWEB)
Daniel P. Molloy
2004-02-24
The specific purpose of this research project was to identify factors that affect zebra mussel kill by the bacterium Pseudomonas fluorescens. Test results obtained during this three-year project identified the following key variables as affecting mussel kill: treatment concentration, treatment duration, mussel siphoning activity, dissolved oxygen concentration, water temperature, and naturally suspended particle load. Using this latter information, the project culminated in a series of pipe tests which achieved high mussel kill inside power plants under once-through conditions using service water in artificial pipes.
Killing by neutrophil extracellular traps: fact or folklore?
Menegazzi, Renzo; Decleva, Eva; Dri, Pietro
2012-02-02
Neutrophil extracellular traps (NETs) are DNA structures released by dying neutrophils and claimed to constitute a new microbicidal mechanism. Killing by NET-forming cells is ascribed to these structures because it is prevented by preincubation with DNase, which has been shown to dismantle NETs, before addition of the target microorganisms. Curiously, the possibility that the microorganisms ensnared in NETs are alive has not been considered. Using Staphylococcus aureus and Candida albicans blastospores, we demonstrate that the microorganisms captured by NETs and thought to be killed are alive because they are released and recovered in cell medium by incubation with DNase. It is concluded that NETs entrap but do not kill microbes.
A conceptual framework for understanding illegal killing of large carnivores.
Carter, Neil H; López-Bao, José Vicente; Bruskotter, Jeremy T; Gore, Meredith; Chapron, Guillaume; Johnson, Arlyne; Epstein, Yaffa; Shrestha, Mahendra; Frank, Jens; Ohrens, Omar; Treves, Adrian
2017-04-01
The growing complexity and global nature of wildlife poaching threaten the survival of many species worldwide and are outpacing conservation efforts. Here, we reviewed proximal and distal factors, both social and ecological, driving illegal killing or poaching of large carnivores at sites where it can potentially occur. Through this review, we developed a conceptual social-ecological system framework that ties together many of the factors influencing large carnivore poaching. Unlike most conservation action models, an important attribute of our framework is the integration of multiple factors related to both human motivations and animal vulnerability into feedbacks. We apply our framework to two case studies, tigers in Laos and wolverines in northern Sweden, to demonstrate its utility in disentangling some of the complex features of carnivore poaching that may have hindered effective responses to the current poaching crisis. Our framework offers a common platform to help guide future research on wildlife poaching feedbacks, which has hitherto been lacking, in order to effectively inform policy making and enforcement.
Directory of Open Access Journals (Sweden)
Hayat Tasawar
2003-01-01
Full Text Available The governing equations for the unsteady flow of a uniformly conducting incompressible fourth-grade fluid due to noncoaxial rotations of a porous disk and the fluid at infinity are constructed. The steady flow of the fourth-grade fluid subjected to a magnetic field with suction/blowing through the disk is studied. The nonlinear ordinary differential equations resulting from the balance of momentum and mass are discretised by a finite-difference method and numerically solved by means of an iteration method in which, by a coordinate transformation, the semi-infinite physical domain is converted to a finite calculation domain. In order to solve the fourth-order nonlinear differential equations, asymptotic boundary conditions at infinity are augmented. The manner in which various material parameters affect the structure of the boundary layer is delineated. It is found that the suction through the disk and the magnetic field tend to thin the boundary layer near the disk for both the Newtonian fluid and the fourth-grade fluid, while the blowing causes a thickening of the boundary layer with the exception of the fourth-grade fluid under strong blowing. With the increase of the higher-order viscosities, the boundary layer has the tendency of thickening.
POSlTlVE SOLUTl0NS 0F A FOURTH 0RDER BOUNDARY VALUE PROBLEM
Institute of Scientific and Technical Information of China (English)
RenLishun
2003-01-01
The existence of positive solutions of the nonlinear fourth order problem u(4)(x)=λα（x)f(u(x)),u(0)=u′（0)=u′（1)=um(1)=0 is studied,where a:[0,1]→R may change sign,f(0)>0,λ>0 is sufficiently small.Our approach is based on the Leray-Schauder fixed point theorem.
Combined search for the quarks of a sequential fourth generation
Chatrchyan, S.; Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Aguilo, E.; Bergauer, T.; Dragicevic, M.; Erö, J.; Fabjan, C.; Friedl, M.; Frühwirth, R.; Ghete, V. M.; Hammer, J.; Hörmann, N.; Hrubec, J.; Jeitler, M.; Kiesenhofer, W.; Knünz, V.; Krammer, M.; Krätschmer, I.; Liko, D.; Mikulec, I.; Pernicka, M.; Rahbaran, B.; Rohringer, C.; Rohringer, H.; Schöfbeck, R.; Strauss, J.; Taurok, A.; Waltenberger, W.; Walzel, G.; Widl, E.; Wulz, C.-E.; Mossolov, V.; Shumeiko, N.; Suarez Gonzalez, J.; Bansal, M.; Bansal, S.; Cornelis, T.; De Wolf, E. A.; Janssen, X.; Luyckx, S.; Mucibello, L.; Ochesanu, S.; Roland, B.; Rougny, R.; Selvaggi, M.; Staykova, Z.; Van Haevermaet, H.; Van Mechelen, P.; Van Remortel, N.; Van Spilbeeck, A.; Blekman, F.; Blyweert, S.; D'Hondt, J.; Gonzalez Suarez, R.; Kalogeropoulos, A.; Maes, M.; Olbrechts, A.; Van Doninck, W.; Van Mulders, P.; Van Onsem, G. P.; Villella, I.; Clerbaux, B.; De Lentdecker, G.; Dero, V.; Gay, A. P. R.; Hreus, T.; Léonard, A.; Marage, P. E.; Mohammadi, A.; Reis, T.; Thomas, L.; Vander Marcken, G.; Vander Velde, C.; Vanlaer, P.; Wang, J.; Adler, V.; Beernaert, K.; Cimmino, A.; Costantini, S.; Garcia, G.; Grunewald, M.; Klein, B.; Lellouch, J.; Marinov, A.; Mccartin, J.; Ocampo Rios, A. A.; Ryckbosch, D.; Strobbe, N.; Thyssen, F.; Tytgat, M.; Verwilligen, P.; Walsh, S.; Yazgan, E.; Zaganidis, N.; Basegmez, S.; Bruno, G.; Castello, R.; Ceard, L.; Delaere, C.; du Pree, T.; Favart, D.; Forthomme, L.; Giammanco, A.; Hollar, J.; Lemaitre, V.; Liao, J.; Militaru, O.; Nuttens, C.; Pagano, D.; Pin, A.; Piotrzkowski, K.; Schul, N.; Vizan Garcia, J. M.; Beliy, N.; Caebergs, T.; Daubie, E.; Hammad, G. H.; Alves, G. A.; Correa Martins Junior, M.; De Jesus Damiao, D.; Martins, T.; Pol, M. E.; Souza, M. H. G.; Aldá Júnior, W. L.; Carvalho, W.; Custódio, A.; Da Costa, E. M.; De Oliveira Martins, C.; Fonseca De Souza, S.; Matos Figueiredo, D.; Mundim, L.; Nogima, H.; Oguri, V.; Prado Da Silva, W. L.; Santoro, A.; Soares Jorge, L.; Sznajder, A.; Anjos, T. S.; Bernardes, C. A.; Dias, F. A.; Tomei, T. R. Fernandez Perez; Gregores, E. M.; Lagana, C.; Marinho, F.; Mercadante, P. G.; Novaes, S. F.; Padula, Sandra S.; Genchev, V.; Iaydjiev, P.; Piperov, S.; Rodozov, M.; Stoykova, S.; Sultanov, G.; Tcholakov, V.; Trayanov, R.; Vutova, M.; Dimitrov, A.; Hadjiiska, R.; Kozhuharov, V.; Litov, L.; Pavlov, B.; Petkov, P.; Bian, J. G.; Chen, G. M.; Chen, H. S.; Jiang, C. H.; Liang, D.; Liang, S.; Meng, X.; Tao, J.; Wang, J.; Wang, X.; Wang, Z.; Xiao, H.; Xu, M.; Zang, J.; Zhang, Z.; Asawatangtrakuldee, C.; Ban, Y.; Guo, S.; Guo, Y.; Li, W.; Liu, S.; Mao, Y.; Qian, S. J.; Teng, H.; Wang, D.; Zhang, L.; Zhu, B.; Zou, W.; Avila, C.; Gomez, J. P.; Gomez Moreno, B.; Osorio Oliveros, A. F.; Sanabria, J. C.; Godinovic, N.; Lelas, D.; Plestina, R.; Polic, D.; Puljak, I.; Antunovic, Z.; Kovac, M.; Brigljevic, V.; Duric, S.; Kadija, K.; Luetic, J.; Morovic, S.; Attikis, A.; Galanti, M.; Mavromanolakis, G.; Mousa, J.; Nicolaou, C.; Ptochos, F.; Razis, P. A.; Finger, M.; Finger, M., Jr.; Assran, Y.; Elgammal, S.; Ellithi Kamel, A.; Khalil, S.; Mahmoud, M. A.; Radi, A.; Kadastik, M.; Müntel, M.; Raidal, M.; Rebane, L.; Tiko, A.; Eerola, P.; Fedi, G.; Voutilainen, M.; Härkönen, J.; Heikkinen, A.; Karimäki, V.; Kinnunen, R.; Kortelainen, M. J.; Lampén, T.; Lassila-Perini, K.; Lehti, S.; Lindén, T.; Luukka, P.; Mäenpää, T.; Peltola, T.; Tuominen, E.; Tuominiemi, J.; Tuovinen, E.; Ungaro, D.; Wendland, L.; Banzuzi, K.; Karjalainen, A.; Korpela, A.; Tuuva, T.; Besancon, M.; Choudhury, S.; Dejardin, M.; Denegri, D.; Fabbro, B.; Faure, J. L.; Ferri, F.; Ganjour, S.; Givernaud, A.; Gras, P.; Hamel de Monchenault, G.; Jarry, P.; Locci, E.; Malcles, J.; Millischer, L.; Nayak, A.; Rander, J.; Rosowsky, A.; Shreyber, I.; Titov, M.; Baffioni, S.; Beaudette, F.; Benhabib, L.; Bianchini, L.; Bluj, M.; Broutin, C.; Busson, P.; Charlot, C.; Daci, N.; Dahms, T.; Dobrzynski, L.; Granier de Cassagnac, R.; Haguenauer, M.; Miné, P.; Mironov, C.; Naranjo, I. N.; Nguyen, M.; Ochando, C.; Paganini, P.; Sabes, D.; Salerno, R.; Sirois, Y.; Veelken, C.; Zabi, A.; Agram, J.-L.; Andrea, J.; Bloch, D.; Bodin, D.; Brom, J.-M.; Cardaci, M.; Chabert, E. C.; Collard, C.; Conte, E.; Drouhin, F.; Ferro, C.; Fontaine, J.-C.; Gelé, D.; Goerlach, U.; Juillot, P.; Le Bihan, A.-C.; Van Hove, P.; Fassi, F.; Mercier, D.; Beauceron, S.; Beaupere, N.; Bondu, O.; Boudoul, G.; Chasserat, J.; Chierici, R.; Contardo, D.; Depasse, P.; El Mamouni, H.; Fay, J.; Gascon, S.; Gouzevitch, M.; Ille, B.; Kurca, T.; Lethuillier, M.; Mirabito, L.; Perries, S.; Sordini, V.; Tschudi, Y.; Verdier, P.; Viret, S.; Tsamalaidze, Z.; Anagnostou, G.; Beranek, S.; Edelhoff, M.; Feld, L.; Heracleous, N.; Hindrichs, O.; Jussen, R.
2012-12-01
Results are presented from a search for a fourth generation of quarks produced singly or in pairs in a data set corresponding to an integrated luminosity of 5fb-1 recorded by the CMS experiment at the LHC in 2011. A novel strategy has been developed for a combined search for quarks of the up and down type in decay channels with at least one isolated muon or electron. Limits on the mass of the fourth-generation quarks and the relevant Cabibbo-Kobayashi-Maskawa matrix elements are derived in the context of a simple extension of the standard model with a sequential fourth generation of fermions. The existence of mass-degenerate fourth-generation quarks with masses below 685 GeV is excluded at 95% confidence level for minimal off-diagonal mixing between the third- and the fourth-generation quarks. With a mass difference of 25 GeV between the quark masses, the obtained limit on the masses of the fourth-generation quarks shifts by about ±20GeV. These results significantly reduce the allowed parameter space for a fourth generation of fermions.
Robust Optimization of Fourth Party Logistics Network Design under Disruptions
Directory of Open Access Journals (Sweden)
Jia Li
2015-01-01
Full Text Available The Fourth Party Logistics (4PL network faces disruptions of various sorts under the dynamic and complex environment. In order to explore the robustness of the network, the 4PL network design with consideration of random disruptions is studied. The purpose of the research is to construct a 4PL network that can provide satisfactory service to customers at a lower cost when disruptions strike. Based on the definition of β-robustness, a robust optimization model of 4PL network design under disruptions is established. Based on the NP-hard characteristic of the problem, the artificial fish swarm algorithm (AFSA and the genetic algorithm (GA are developed. The effectiveness of the algorithms is tested and compared by simulation examples. By comparing the optimal solutions of the 4PL network for different robustness level, it is indicated that the robust optimization model can evade the market risks effectively and save the cost in the maximum limit when it is applied to 4PL network design.
The fourth horizontal project in the mature Algyo Field
Energy Technology Data Exchange (ETDEWEB)
Pipicz, V.; Benedek, L.; Palasthy, G.; Barodi, T. [MOL Hungarian Oil and Gas Co. (Hungary); Joshi, S.D. [Joshi Technologies International, Tulsa, OK (United States)
2002-07-01
Approximately seventy horizontal wells have been drilled in the course of three successful projects in the mature Algyo Field in Hungary since 1993. Recently, a fourth project has been initiated which includes the drilling of more than twenty new horizontal sections. These horizontal wells kick off existing abandoned wells along the thin oil rim that exists in two high permeability reservoirs with top gas and bottom water. The most significant difference between the two reservoirs is that one has water injection and the other has two layers with strong natural bottom water drive. The former geological and dynamic models for the hydrocarbon field in the Pannonian basin was rebuilt in order to handle the common aquifer of four reservoirs. Based on the new geology, reservoir simulation was used to study the reservoir behaviour, including the forthcoming period of gas cap production. The increase in reserves was matched with the production history to observe the movement of the water oil contact (WOC) with the production and drawdown rates in the future when the horizontal trajectories were planned. The reservoir management focused on maximising the long-term profit of the field by optimal production of the reserves, reducing gas and water coning and by the effective use of depleted gas reservoirs and existing vertical wells. Production rate and recovery was increased by reaching the by-passed hydrocarbon and by increasing the drainage area. 6 refs., 3 tabs., 14 figs.
The superior transvelar approach to the fourth ventricle and brainstem.
Ezer, Haim; Banerjee, Anirban Deep; Bollam, Papireddy; Guthikonda, Bharat; Nanda, Anil
2012-06-01
Objective The superior transvelar approach is used to access pathologies located in the fourth ventricle and brainstem. The surgical path is below the venous structures, through the superior medullary velum. Following splitting the tentorial edge, near the tentorial apex, the superior medullary velum is split in the cerebello-mesencephalic fissure. Using the supracerebellar infratentorial, transtentorial or parietal interhemispheric routes, the superior medullary velum is approached. Splitting this velum provides a detailed view of the fourth ventricle and its floor. Materials and Methods A total of 10 formalin-fixed specimens were dissected in a stepwise manner to simulate the superior transvelar approach to the fourth ventricle. The exposure gained the distance from the craniotomy site and the ease of access was assessed for each of the routes. We also present an illustrative case, operated by the senior author (AN). Results The superior transvelar approach provides access to the entire length of the fourth ventricle floor, from the aqueduct to the obex, when using the parietal interhemispheric route. In addition, this approach provides access to the entire width of the floor of the fourth ventricle; however, this requires retracting the superior cerebellar peduncle. Using the supracerebellar infratentorial route gives a limited exposure of the superior part of the fourth ventricle. The occipital interhemispheric route is a compromise between these two. Conclusion The superior transvelar approach to the fourth ventricle provides a route for approaching the fourth ventricle from above. This approach does not require opening the posterior fossa in the traditional way, and provides a reasonable alternative for accessing the superior fourth ventricle.
Contagion in Mass Killings and School Shootings: e0117259
National Research Council Canada - National Science Library
Sherry Towers; Andres Gomez-Lievano; Maryam Khan; Anuj Mubayi; Carlos Castillo-Chavez
2015-01-01
... to the coverage planting the seeds of ideation in at-risk individuals to commit similar acts. Methods Here we explore whether or not contagion is evident in more high-profile incidents, such as school shootings and mass killings...
Fish Kill Investigations : St. Vincent National Wildlife Refuge
US Fish and Wildlife Service, Department of the Interior — This memo summarizes an investigation that took place after a massive fish kill in 5 of the 6 ponds on St. Vincent National Wildlife Refuge. Two days of field...
'Superbug' Resistant to All Antibiotics Killed Nevada Woman
... news/fullstory_163038.html 'Superbug' Resistant to All Antibiotics Killed Nevada Woman She died after possibly picking ... September from a "superbug" infection that resisted all antibiotics, according to a report released Friday. The case ...
Canada goose kill statistics: Swan Lake Public Hunting Area
US Fish and Wildlife Service, Department of the Interior — This document discusses how the flexible kill formula for Canada goose hunting at Swan Lake Public Hunting Area was reached. Methods used to collect Canada goose...
Ricci flow, Killing spinors, and T-duality in generalized geometry
Garcia-Fernandez, Mario
2016-01-01
We introduce a notion of Ricci flow in generalized geometry, extending a previous definition by Gualtieri on exact Courant algebroids. Special stationary points of the flow are given by solutions to first-order differential equations, the Killing spinor equations, which encompass special holonomy metrics with solutions of the Strominger system. Our main result investigates a method to produce new solutions of the Ricci flow and the Killing spinor equations. For this, we consider T-duality between possibly topologically distinct torus bundles endowed with Courant structures, and demonstrate that solutions of the equations are exchanged under this symmetry. As applications, we give a mathematical explanation of the dilaton shift in string theory and prove that the Strominger system is preserved by T-duality.
Yangzhou’s Famous Twenty-fourth Bridge
Institute of Scientific and Technical Information of China (English)
1992-01-01
“LOOMING green moun-tains and runningstreams;grass does notwither and fall,though the autumnhas come to an end in the south.The bright moon arises overTwenty-fourth Bridge.Where doyou teach pure-jade Yangzhouwomen to play music on bambooflutes?”This poem by Du Mu(803-c.852),a famous poet of thelate Tang Dynasty,is well remem-bered today It made Yangzhou’sTwenty-fourth Bridge Known to la-ter generations.Of many ancientpoems about Twenty-fourth Bridge
Pseudomonas aeruginosa PAO1 Kills Caenorhabditis elegans by Cyanide Poisoning
Gallagher, Larry A.; Manoil, Colin
2001-01-01
In this report we describe experiments to investigate a simple virulence model in which Pseudomonas aeruginosa PAO1 rapidly paralyzes and kills the nematode Caenorhabditis elegans. Our results imply that hydrogen cyanide is the sole or primary toxic factor produced by P. aeruginosa that is responsible for killing of the nematode. Four lines of evidence support this conclusion. First, a transposon insertion mutation in a gene encoding a subunit of hydrogen cyanide synthase (hcnC) eliminated ne...
Moral dilemma: to kill or allow to die?
Cole, J J
1989-01-01
The thesis of this paper is that while allowing a person to die with care can be morally justified in particular cases, the option of mercy killing can never be morally defended. There is a significant moral difference between these two concepts. Furthermore, the wedge argument, the medical fallibility argument, and the medical care and trust argument provide cogent and convincing reasons for maintaining a legal distinction between mercy killing and letting a person die.
Conformal Killing vector fields and a virial theorem
Cariñena, José F; Martínez, Eduardo; Santos, Patrícia
2014-01-01
The virial theorem is formulated both intrinsically and in local coordinates for a Lagrangian system of mechanical type on a Riemann manifold. An import case studied in this paper is that of an affine virial function associated to a vector field on the configuration manifold. The special cases of a virial function associated to a Killing, a homothetic and a conformal Killing vector field are considered and the corresponding virial theorems are established for this type of functions.
Special Killing forms on toric Sasaki-Einstein manifolds
Slesar, Vladimir; Vilcu, Gabriel Eduard
2014-01-01
In this paper we study the interplay between complex coordinates of the Calabi-Yau metric cone and the special Killing forms on the toric Sasaki-Einstein manifold. In the general case we give a procedure to locally construct the special Killing forms. In the final part we exemplify the general scheme in the case of the 5-dimensional $Y^{p,q}$ spaces.
Minimal killing unit of the mitochondrial targeting domain of Noxa.
Kim, Ji-Young; Han, Ji Hye; Moon, Ae-Ran; Park, Jung Hee; Chang, Jeong Hwan; Bae, Jeehyeon; Kim, Tae-Hyoung
2013-08-01
Noxa is a key player in p53-induced cell death via mitochondrial dysfunction, and the mitochondrial-targeting domain (MTD) of Noxa is responsible for the translocation of Noxa to mitochondria and for the induction of necrotic cell death. The purpose of this study was to define the minimal killing unit of MTD in vitro and in vivo. It was found that the peptides R8:MTD(10), R8:MTD(9), and R8:MTD(8) can kill various human tumor cells (HCT116, HeLa, MCF-7, BJAB), but that R8:MTD(7) abolishes the killing activity of MTD mainly because of the loss of mitochondrial targeting activity. We find it interesting that R8:MTD(8) was found to kill tumor cells but showed a limited killing activity on normal peritoneal macrophages. Furthermore, R8:MTD(10), R8:MTD(9), and R8:MTD(8) limitedly suppressed tumor growth when injected i.v. into BalB/C mice bearing CT26 cell-derived tumors. These results indicate that MTD(8) is the minimal killing unit of MTD.
Oxidative and nonoxidative killing of Actinobacillus actinomycetemcomitans by human neutrophils.
Miyasaki, K T; Wilson, M E; Brunetti, A J; Genco, R J
1986-07-01
Actinobacillus actinomycetemcomitans is a facultative gram-negative microorganism which has been implicated as an etiologic agent in localized juvenile periodontitis and in subacute bacterial endocarditis and abscesses. Although resistant to serum bactericidal action and to oxidant injury mediated by superoxide anion (O2-) and hydrogen peroxide (H2O2), this organism is sensitive to killing by the myeloperoxidase-hydrogen peroxide-chloride system (K.T. Miyasaki, M.E. Wilson, and R.J. Genco, Infect. Immun. 53:161-165, 1986). In this study, we examined the sensitivity of A. actinomycetemcomitans to killing by intact neutrophils under aerobic conditions, under anaerobic conditions, and under aerobic conditions in the presence of the heme-protein inhibitor sodium cyanide. Intact neutrophils killed opsonized A. actinomycetemcomitans under aerobic and anaerobic conditions, and the kinetics of these reactions indicated that both oxidative and nonoxidative mechanisms were operative. Oxidative mechanisms contributed significantly, and most of the killing attributable to oxidative mechanisms was inhibited by sodium cyanide, which suggested that the myeloperoxidase-hydrogen peroxide-chloride system participated in the oxidative process. We conclude that human neutrophils are capable of killing A. actinomycetemcomitans by both oxygen-dependent and oxygen-independent pathways, and that most oxygen-dependent killing requires myeloperoxidase activity.
Karr’s Kill Cult: Virtual Cults and Pseudo-Killing in the Digital Age
Directory of Open Access Journals (Sweden)
Jeremy Biles
2012-03-01
Full Text Available Most readers will recall the 1996 tragedy in which six-year-old beauty-pageant princess JonBenét Ramsey was found bound, gagged, and strangled in the basement of her parents’ home, inciting an orgy of media coverage. What readers may not know is that John Mark Karr—the imminently creepy individual who falsely confessed to the killing, and whose sordid past includes an arrest for possession of child pornography—has continued to make news as an alleged cyberstalker and would-be cult leader. This article claims that whereas a real serial killer is compelled to murder again and again with different victims, Karr is compelled to repeat the singular murder of JonBenét Ramsey the only way he can—in a virtual reality constituted by writing.
DEFF Research Database (Denmark)
Rijkhoff, Jan
2015-01-01
The way constituents are ordered in a linguistic expression is determined by general principles and language specific rules. This article is mostly concerned with general ordering principles and the three main linguistic categories that are relevant for constituent order research: formal, functio...
Six, Robert H.; Liebenberg, Julian; Honsberger, Nicole A.; Mahabir, Sean P.
2016-01-01
Background Fleas are the most common ectoparasite infesting dogs globally. The many possible sequellae of infestation include: direct discomfort; allergic reactions; and the transmission of pathogens. Rapid speed of kill is an important characteristic for a parasiticide in order to alleviate the direct deleterious effects of fleas, reduce the impact of allergic responses, and break the flea infestation cycle. In this study, the speed of kill of a novel orally administered isoxazoline parasiti...
The radial velocity experiment (RAVE) : Fourth data release
Kordopatis, G.; Gilmore, G.; Steinmetz, M.; Boeche, C.; Seabroke, G. M.; Siebert, A.; Zwitter, T.; Binney, J.; de Laverny, P.; Recio-Blanco, A.; Williams, M. E. K.; Piffl, T.; Enke, H.; Roeser, S.; Bijaoui, A.; Wyse, R. F. G.; Freeman, K.; Munari, U.; Carrillo, I.; Anguiano, B.; Burton, D.; Campbell, R.; Cass, C. J. P.; Fiegert, K.; Hartley, M.; Parker, Q. A.; Reid, W.; Ritter, A.; Russell, K. S.; Stupar, M.; Watson, F. G.; Bienayme, O.; Bland-Hawthorn, J.; Gerhard, O.; Gibson, B. K.; Grebel, E. K.; Helmi, A.; Navarro, J. F.; Conrad, C.; Famaey, B.; Faure, C.; Just, A.; Kos, J.; Matijevic, G.; McMillan, P. J.; Minchev, I.; Scholz, R.; Sharma, S.; Siviero, A.; de Boer, E. Wylie; Zerjal, M.
2013-01-01
We present the stellar atmospheric parameters (effective temperature, surface gravity, overall metallicity), radial velocities, individual abundances, and distances determined for 425,561 stars, which constitute the fourth public data release of the RAdial Velocity Experiment (RAVE). The stellar atm
Development of neurogenic stress cardiomyopathy after fourth ventricle tumor surgery
Directory of Open Access Journals (Sweden)
D. A. Doroshenko
2014-07-01
Full Text Available The paper describes a clinical case of the development of neurogenic stress cardiomyopathy that had the characteristics of Takotsubo cardiomyopathyin a young female patient in the early periods after fourth ventricle tumor surgery.
Development of neurogenic stress cardiomyopathy after fourth ventricle tumor surgery
Directory of Open Access Journals (Sweden)
D. A. Doroshenko
2012-01-01
Full Text Available The paper describes a clinical case of the development of neurogenic stress cardiomyopathy that had the characteristics of Takotsubo cardiomyopathyin a young female patient in the early periods after fourth ventricle tumor surgery.
The Radial Velocity Experiment (RAVE): Fourth Data Release
Kordopatis, G.; Gilmore, G.; Steinmetz, M.; Boeche, C.; Seabroke, G. M.; Siebert, A.; Zwitter, T.; Binney, J.; de Laverny, P.; Recio-Blanco, A.; Williams, M. E. K.; Piffl, T.; Enke, H.; Roeser, S.; Bijaoui, A.; Wyse, R. F. G.; Freeman, K.; Munari, U.; Carrillo, I.; Anguiano, B.; Burton, D.; Campbell, R.; Cass, C. J. P.; Fiegert, K.; Hartley, M.; Parker, Q. A.; Reid, W.; Ritter, A.; Russell, K. S.; Stupar, M.; Watson, F. G.; Bienaymé, O.; Bland-Hawthorn, J.; Gerhard, O.; Gibson, B. K.; Grebel, E. K.; Helmi, A.; Navarro, J. F.; Conrad, C.; Famaey, B.; Faure, C.; Just, A.; Kos, J.; Matijevič, G.; McMillan, P. J.; Minchev, I.; Scholz, R.; Sharma, S.; Siviero, A.; de Boer, E. Wylie; Žerjal, M.
2013-01-01
We present the stellar atmospheric parameters (effective temperature, surface gravity, overall metallicity), radial velocities, individual abundances, and distances determined for 425,561 stars, which constitute the fourth public data release of the RAdial Velocity Experiment (RAVE). The stellar atm
Solar Energy Technologies Program Newsletter - Fourth Quarter 2009
Energy Technology Data Exchange (ETDEWEB)
DOE Solar Energy Technologies Program
2009-12-31
The Fourth Quarter 2009 edition of the Solar Energy Technologies Program newsletter summarizes the activities for the past three months, funding opportunities, highlights from the national labs, and upcoming events.
Astrophysical Tests of Kinematical Conformal Cosmology in Fourth-Order Conformal Weyl Gravity
Directory of Open Access Journals (Sweden)
Gabriele U. Varieschi
2014-12-01
Full Text Available In this work we analyze kinematical conformal cosmology (KCC, an alternative cosmological model based on conformal Weyl gravity (CG, and test it against current type Ia supernova (SNIa luminosity data and other astrophysical observations. Expanding upon previous work on the subject, we revise the analysis of SNIa data, confirming that KCC can explain the evidence for an accelerating expansion of the Universe without using dark energy or other exotic components. We obtain an independent evaluation of the Hubble constant, H0 = 67:53 kms-1 Mpc-1, very close to the current best estimates. The main KCC and CG parameters are re-evaluated and their revised values are found to be close to previous estimates. We also show that available data for the Hubble parameter as a function of redshift can be fitted using KCC and that this model does not suffer from any apparent age problem. Overall,
Fourth-order-dispersion limitations of aberration-free chirped-pulse amplification systems
Energy Technology Data Exchange (ETDEWEB)
Kane, S. [Center for Ultrafast Optical Science, University of Michigan, 2200 Bonisteel Boulevard, Room 1006, Institute for Science and Technology Building, Ann Arbor, Michigan 48109-2099 (United States); Squier, J. [Institute for Nonlinear Science, University of California, San Diego, Urey Hall, Mail Code 0339, La Jolla, California 92093-0339 (United States)
1997-05-01
To obtain shorter pulses in chirped-pulse-amplification lasers, researchers have recently proposed several designs for aberration-free pulse stretchers. We examine the limitations of two aberration-free chirped-pulse-amplification systems and show that comparable results can be obtained with simpler, conventional pulse stretchers. In addition, we present a simple, quintic-phase-limited, aberration-free chirped-pulse-amplification system that can support ultrashort, high-contrast pulses. {copyright} 1997 Optical Society of America
Fourth-order dispersion mediated solitonic radiations in HC-PCF cladding
DEFF Research Database (Denmark)
Benabid, F.; Biancalana, F.; Light, P.S.;
2008-01-01
We observe experimentally, for the first time to our knowledge, the simultaneous emission of two strong conjugate resonant dispersive waves emitted by optical solitons. The effect is observed in a small waveguiding glass-feature within the cladding of a Kagome hollow-core photonic crystal fiber. We...
Existence of solutions for fourth-order PDEs with variable exponents
Directory of Open Access Journals (Sweden)
Mimoun Moussaoui
2009-11-01
Full Text Available In this article, we study the following problem with Navier boundary conditions $$displaylines{ Delta _{p(x}^2u=lambda | u| ^{p(x-2}u+f(x,uquad hbox{in }Omega , cr u=Delta u=0quad hbox{on }partial Omega . }$$ Where $Omega $ is a bounded domain in $mathbb{R}^{N}$ with smooth boundary $partial Omega $, $Ngeq 1$, $Delta _{p(x}^2u:=Delta (|Delta u| ^{p(x-2}Delta u $, is the $p(x$-biharmonic operator, $lambda leq 0$, $p$ is a continuous function on $overline{Omega } $ with $inf_{xin overline{Omega }} p(x>1$ and $f:Omega imes mathbb{R}o mathbb{R}$ is a Caratheodory function. Using the Mountain Pass Theorem, we establish the existence of at least one solution of this problem. Especially, the existence of infinite many solutions is obtained.
SOME n-RECTANGLE NONCONFORMING ELEMENTS FOR FOURTH ORDER ELLIPTIC EQUATIONS
Institute of Scientific and Technical Information of China (English)
Ming Wang; Zhong-Ci Shi; Jinchao Xu
2007-01-01
In this paper, three n-rectangle nonconforming elements are proposed with n ≥ 3. They are the extensions of well-known Morley element, Adini element and Bogner-Fox-Schmit element in two spatial dimensions to any higher dimensions respectively. These elements are all proved to be convergent for a model biharmonic equation in n dimensions.
Inverse-Definiteness of the Fourth-Order Symmetric Differential Operator (Ⅰ)
Institute of Scientific and Technical Information of China (English)
Wei Yin YE
2004-01-01
We give a linear symmetric differential operator L defined by L := D4 + bD2 + aIin the 2π-periodic function space, and study the inverse-definiteness property of L. We obtain a complete result about the inverse-definiteness property of L with real constants a and b when b2 -4a ＞ 0and a- bk2 + k4 ≠ 0 for any k ∈ {1,2,3,...}.
Orthogonal Polynomials on the Unit Ball and Fourth-Order Partial Differential Equations
Martínez, Clotilde; Piñar, Miguel A.
2016-02-01
The purpose of this work is to analyse a family of mutually orthogonal polynomials on the unit ball with respect to an inner product which includes an additional term on the sphere. First, we will get connection formulas relating classical multivariate orthogonal polynomials on the ball with our family of orthogonal polynomials. Then, using the representation of these polynomials in terms of spherical harmonics, algebraic and differential properties will be deduced.
Oscillation Criteria for Fourth-Order Nonlinear Dynamic Equations on Time Scales
Directory of Open Access Journals (Sweden)
Xin Wu
2013-01-01
Full Text Available We establish some new oscillation criteria for nonlinear dynamic equation of the form on an arbitrary time scale with , where are positive rd-continuous functions. An example illustrating the importance of our result is included.
PEP-X: An Ultimate Storage Ring Based on Fourth-Order Geometric Achromats
Energy Technology Data Exchange (ETDEWEB)
Cai, Yunhai; Bane, Karl; Hettel, Robert; Nosochkov, Yuri; Wang, Min-Huey; /SLAC
2012-04-06
We have designed an 'ultimate' storage ring for the PEP-X light source that achieves the diffraction limited emittances (at 1.5 {angstrom}) of 12 pm-rad in both horizontal and vertical planes with a 4.5-GeV beam. These emittances include the contribution of intrabeam scattering at a nominal current of 200 mA in 3300 bunches. This quality beam in conjunction with a conventional 4-m undulator in a straight section can generate synchrotron radiation having a spectral brightness above 10{sup 22} [photons/s/mm{sup 2}/mrad{sup 2}/0.1% BW] at a 10 keV photon energy. The high coherence at the diffraction limit makes PEP-X competitive with 4th generation light sources based on an energy recovery linac. In addition, the beam lifetime is several hours and the dynamic aperture is large enough to allow off-axis injection. The alignment and stability tolerances, though challenging, are achievable. A ring with all these properties is only possible because of several major advances in mitigating the effects of nonlinear resonances.
Combined search for the quarks of a sequential fourth generation
Chatrchyan, Serguei; Sirunyan, Albert M; Tumasyan, Armen; Adam, Wolfgang; Aguilo, Ernest; Bergauer, Thomas; Dragicevic, Marko; Erö, Janos; Fabjan, Christian; Friedl, Markus; Fruehwirth, Rudolf; Ghete, Vasile Mihai; Hammer, Josef; Hörmann, Natascha; Hrubec, Josef; Jeitler, Manfred; Kiesenhofer, Wolfgang; Knünz, Valentin; Krammer, Manfred; Krätschmer, Ilse; Liko, Dietrich; Mikulec, Ivan; Pernicka, Manfred; Rahbaran, Babak; Rohringer, Christine; Rohringer, Herbert; Schöfbeck, Robert; Strauss, Josef; Taurok, Anton; Waltenberger, Wolfgang; Walzel, Gerhard; Widl, Edmund; Wulz, Claudia-Elisabeth; Mossolov, Vladimir; Shumeiko, Nikolai; Suarez Gonzalez, Juan; Bansal, Monika; Bansal, Sunil; Cornelis, Tom; De Wolf, Eddi A; Janssen, Xavier; Luyckx, Sten; Mucibello, Luca; Ochesanu, Silvia; Roland, Benoit; Rougny, Romain; Selvaggi, Michele; Staykova, Zlatka; Van Haevermaet, Hans; Van Mechelen, Pierre; Van Remortel, Nick; Van Spilbeeck, Alex; Blekman, Freya; Blyweert, Stijn; D'Hondt, Jorgen; Gonzalez Suarez, Rebeca; Kalogeropoulos, Alexis; Maes, Michael; Olbrechts, Annik; Van Doninck, Walter; Van Mulders, Petra; Van Onsem, Gerrit Patrick; Villella, Ilaria; Clerbaux, Barbara; De Lentdecker, Gilles; Dero, Vincent; Gay, Arnaud; Hreus, Tomas; Léonard, Alexandre; Marage, Pierre Edouard; Mohammadi, Abdollah; Reis, Thomas; Thomas, Laurent; Vander Marcken, Gil; Vander Velde, Catherine; Vanlaer, Pascal; Wang, Jian; Adler, Volker; Beernaert, Kelly; Cimmino, Anna; Costantini, Silvia; Garcia, Guillaume; Grunewald, Martin; Klein, Benjamin; Lellouch, Jérémie; Marinov, Andrey; Mccartin, Joseph; Ocampo Rios, Alberto Andres; Ryckbosch, Dirk; Strobbe, Nadja; Thyssen, Filip; Tytgat, Michael; Verwilligen, Piet; Walsh, Sinead; Yazgan, Efe; Zaganidis, Nicolas; Basegmez, Suzan; Bruno, Giacomo; Castello, Roberto; Ceard, Ludivine; Delaere, Christophe; Du Pree, Tristan; Favart, Denis; Forthomme, Laurent; Giammanco, Andrea; Hollar, Jonathan; Lemaitre, Vincent; Liao, Junhui; Militaru, Otilia; Nuttens, Claude; Pagano, Davide; Pin, Arnaud; Piotrzkowski, Krzysztof; Schul, Nicolas; Vizan Garcia, Jesus Manuel; Beliy, Nikita; Caebergs, Thierry; Daubie, Evelyne; Hammad, Gregory Habib; Alves, Gilvan; Correa Martins Junior, Marcos; De Jesus Damiao, Dilson; Martins, Thiago; Pol, Maria Elena; Henrique Gomes E Souza, Moacyr; Aldá Júnior, Walter Luiz; Carvalho, Wagner; Custódio, Analu; Da Costa, Eliza Melo; De Oliveira Martins, Carley; Fonseca De Souza, Sandro; Matos Figueiredo, Diego; Mundim, Luiz; Nogima, Helio; Oguri, Vitor; Prado Da Silva, Wanda Lucia; Santoro, Alberto; Soares Jorge, Luana; Sznajder, Andre; Souza Dos Anjos, Tiago; Bernardes, Cesar Augusto; De Almeida Dias, Flavia; Tomei, Thiago; De Moraes Gregores, Eduardo; Lagana, Caio; Da Cunha Marinho, Franciole; Mercadante, Pedro G; Novaes, Sergio F; Padula, Sandra; Genchev, Vladimir; Iaydjiev, Plamen; Piperov, Stefan; Rodozov, Mircho; Stoykova, Stefka; Sultanov, Georgi; Tcholakov, Vanio; Trayanov, Rumen; Vutova, Mariana; Dimitrov, Anton; Hadjiiska, Roumyana; Kozhuharov, Venelin; Litov, Leander; Pavlov, Borislav; Petkov, Peicho; Bian, Jian-Guo; Chen, Guo-Ming; Chen, He-Sheng; Jiang, Chun-Hua; Liang, Dong; Liang, Song; Meng, Xiangwei; Tao, Junquan; Wang, Jian; Wang, Xianyou; Wang, Zheng; Xiao, Hong; Xu, Ming; Zang, Jingjing; Zhang, Zhen; Asawatangtrakuldee, Chayanit; Ban, Yong; Guo, Shuang; Guo, Yifei; Li, Wenbo; Liu, Shuai; Mao, Yajun; Qian, Si-Jin; Teng, Haiyun; Wang, Dayong; Zhang, Linlin; Zhu, Bo; Zou, Wei; Avila, Carlos; Gomez, Juan Pablo; Gomez Moreno, Bernardo; Osorio Oliveros, Andres Felipe; Sanabria, Juan Carlos; Godinovic, Nikola; Lelas, Damir; Plestina, Roko; Polic, Dunja; Puljak, Ivica; Antunovic, Zeljko; Kovac, Marko; Brigljevic, Vuko; Duric, Senka; Kadija, Kreso; Luetic, Jelena; Morovic, Srecko; Attikis, Alexandros; Galanti, Mario; Mavromanolakis, Georgios; Mousa, Jehad; Nicolaou, Charalambos; Ptochos, Fotios; Razis, Panos A; Finger, Miroslav; Finger Jr, Michael; Assran, Yasser; Elgammal, Sherif; Ellithi Kamel, Ali; Khalil, Shaaban; Mahmoud, Mohammed; Radi, Amr; Kadastik, Mario; Müntel, Mait; Raidal, Martti; Rebane, Liis; Tiko, Andres; Eerola, Paula; Fedi, Giacomo; Voutilainen, Mikko; Härkönen, Jaakko; Heikkinen, Mika Aatos; Karimäki, Veikko; Kinnunen, Ritva; Kortelainen, Matti J; Lampén, Tapio; Lassila-Perini, Kati; Lehti, Sami; Lindén, Tomas; Luukka, Panja-Riina; Mäenpää, Teppo; Peltola, Timo; Tuominen, Eija; Tuominiemi, Jorma; Tuovinen, Esa; Ungaro, Donatella; Wendland, Lauri; Banzuzi, Kukka; Karjalainen, Ahti; Korpela, Arja; Tuuva, Tuure; Besancon, Marc; Choudhury, Somnath
2012-01-01
Results are presented from a search for a fourth generation of quarks produced singly or in pairs in a data set corresponding to an integrated luminosity of 5 inverse femtobarns recorded by the CMS experiment at the LHC in 2011. A novel strategy has been developed for a combined search for quarks of the up- and down-type in decay channels with at least one isolated muon or electron. Limits on the mass of the fourth-generation quarks and the relevant CKM matrix elements are derived in the context of a simple extension of the standard model with a sequential fourth generation of fermions. The existence of mass-degenerate fourth-generation quarks with masses below 685 GeV is excluded at 95% confidence level for minimal off-diagonal mixing between the third- and the fourth-generation quarks. With a mass difference of 25 GeV between the quark masses, the obtained limit on the masses of the fourth-generation quarks shifts by about +/- 20 GeV. This result significantly reduces the allowed parameter space for a fourt...
Directory of Open Access Journals (Sweden)
Paulo A Garcia
Full Text Available Electroporation-based therapies are powerful biotechnological tools for enhancing the delivery of exogeneous agents or killing tissue with pulsed electric fields (PEFs. Electrochemotherapy (ECT and gene therapy based on gene electrotransfer (EGT both use reversible electroporation to deliver chemotherapeutics or plasmid DNA into cells, respectively. In both ECT and EGT, the goal is to permeabilize the cell membrane while maintaining high cell viability in order to facilitate drug or gene transport into the cell cytoplasm and induce a therapeutic response. Irreversible electroporation (IRE results in cell kill due to exposure to PEFs without drugs and is under clinical evaluation for treating otherwise unresectable tumors. These PEF therapies rely mainly on the electric field distributions and do not require changes in tissue temperature for their effectiveness. However, in immediate vicinity of the electrodes the treatment may results in cell kill due to thermal damage because of the inhomogeneous electric field distribution and high current density during the electroporation-based therapies. Therefore, the main objective of this numerical study is to evaluate the influence of pulse number and electrical conductivity in the predicted cell kill zone due to irreversible electroporation and thermal damage. Specifically, we simulated a typical IRE protocol that employs ninety 100-µs PEFs. Our results confirm that it is possible to achieve predominant cell kill due to electroporation if the PEF parameters are chosen carefully. However, if either the pulse number and/or the tissue conductivity are too high, there is also potential to achieve cell kill due to thermal damage in the immediate vicinity of the electrodes. Therefore, it is critical for physicians to be mindful of placement of electrodes with respect to critical tissue structures and treatment parameters in order to maintain the non-thermal benefits of electroporation and prevent