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Sample records for nonlinear nonlocal cochlear

  1. Modulational instability in nonlocal nonlinear Kerr media

    DEFF Research Database (Denmark)

    Krolikowski, Wieslaw; Bang, Ole; Juul Rasmussen, Jens

    2001-01-01

    We study modulational instability (MI) of plane waves in nonlocal nonlinear Kerr media. For a focusing nonlinearity we show that, although the nonlocality tends to suppress MI, it can never remove it completely, irrespective of the particular profile of the nonlocal response function. For a defoc...

  2. Collapse arrest and soliton stabilization in nonlocal nonlinear media

    DEFF Research Database (Denmark)

    Bang, Ole; Krolikowski, Wieslaw; Wyller, John

    2002-01-01

    We investigate the properties of localized waves in cubic nonlinear materials with a symmetric nonlocal nonlinear response of arbitrary shape and degree of nonlocality, described by a general nonlocal nonlinear Schrodinger type equation. We prove rigorously by bounding the Hamiltonian that nonloc......We investigate the properties of localized waves in cubic nonlinear materials with a symmetric nonlocal nonlinear response of arbitrary shape and degree of nonlocality, described by a general nonlocal nonlinear Schrodinger type equation. We prove rigorously by bounding the Hamiltonian...

  3. Solitons in nonlocal nonlinear media: Exact solutions

    DEFF Research Database (Denmark)

    Krolikowski, Wieslaw; Bang, Ole

    2001-01-01

    We investigate the propagation of one-dimensional bright and dark spatial solitons in a nonlocal Kerr-like media, in which the nonlocality is of general form. We find an exact analytical solution to the nonlinear propagation equation in the case of weak nonlocality. We study the properties...... of these solitons and show their stability....

  4. Ring vortex solitons in nonlocal nonlinear media

    DEFF Research Database (Denmark)

    Briedis, D.; Petersen, D.E.; Edmundson, D.

    2005-01-01

    We study the formation and propagation of two-dimensional vortex solitons, i.e. solitons with a phase singularity, in optical materials with a nonlocal focusing nonlinearity. We show that nonlocality stabilizes the dynamics of an otherwise unstable vortex beam. This occurs for either single...... or higher charge fundamental vortices as well as higher order (multiple ring) vortex solitons. Our results pave the way for experimental observation of stable vortex rings in other nonlocal nonlinear systems including Bose-Einstein condensates with pronounced long-range interparticle interaction....

  5. Optical Beams in Nonlocal Nonlinear Media

    DEFF Research Database (Denmark)

    Królikowski, W.; Bang, Ole; Wyller, J.

    2003-01-01

    We discuss propagation of optical beams in nonlocal Kerr-like media with the nonlocality of general form. We study the effect of nonlocality on modulational instability of the plane wave fronts, collapse of finite beams and formation of spatial solitons.......We discuss propagation of optical beams in nonlocal Kerr-like media with the nonlocality of general form. We study the effect of nonlocality on modulational instability of the plane wave fronts, collapse of finite beams and formation of spatial solitons....

  6. The Human Cochlear Mechanical Nonlinearity Inferred via Psychometric Functions

    Directory of Open Access Journals (Sweden)

    Nizami Lance

    2013-12-01

    Extension of the model of Schairer and colleagues results in credible cochlear nonlinearities in man, suggesting that forward-masking provides a non-invasive way to infer the human mechanical cochlear nonlinearity.

  7. Nonlocal nonlinear coupling of kinetic sound waves

    Directory of Open Access Journals (Sweden)

    O. Lyubchyk

    2014-11-01

    Full Text Available We study three-wave resonant interactions among kinetic-scale oblique sound waves in the low-frequency range below the ion cyclotron frequency. The nonlinear eigenmode equation is derived in the framework of a two-fluid plasma model. Because of dispersive modifications at small wavelengths perpendicular to the background magnetic field, these waves become a decay-type mode. We found two decay channels, one into co-propagating product waves (forward decay, and another into counter-propagating product waves (reverse decay. All wavenumbers in the forward decay are similar and hence this decay is local in wavenumber space. On the contrary, the reverse decay generates waves with wavenumbers that are much larger than in the original pump waves and is therefore intrinsically nonlocal. In general, the reverse decay is significantly faster than the forward one, suggesting a nonlocal spectral transport induced by oblique sound waves. Even with low-amplitude sound waves the nonlinear interaction rate is larger than the collisionless dissipation rate. Possible applications regarding acoustic waves observed in the solar corona, solar wind, and topside ionosphere are briefly discussed.

  8. Nonlocal description of X waves in quadratic nonlinear materials

    DEFF Research Database (Denmark)

    Larsen, Peter Ulrik Vingaard; Sørensen, Mads Peter; Bang, Ole

    2006-01-01

    We study localized light bullets and X-waves in quadratic media and show how the notion of nonlocality can provide an alternative simple physical picture of both types of multi-dimensional nonlinear waves. For X-waves we show that a local cascading limit in terms of a nonlinear Schrodinger equation...... does not exist - one needs to use the nonlocal description, because the nonlocal response function does not converge towards a delta-function. Also, we use the nonlocal theory to show for the first time that the coupling to second harmonic is able to generate an X-shape in the fundamental field despite...

  9. Nonlinear Dynamics of Silicon Nanowire Resonator Considering Nonlocal Effect.

    Science.gov (United States)

    Jin, Leisheng; Li, Lijie

    2017-12-01

    In this work, nonlinear dynamics of silicon nanowire resonator considering nonlocal effect has been investigated. For the first time, dynamical parameters (e.g., resonant frequency, Duffing coefficient, and the damping ratio) that directly influence the nonlinear dynamics of the nanostructure have been derived. Subsequently, by calculating their response with the varied nonlocal coefficient, it is unveiled that the nonlocal effect makes more obvious impacts at the starting range (from zero to a small value), while the impact of nonlocal effect becomes weaker when the nonlocal term reaches to a certain threshold value. Furthermore, to characterize the role played by nonlocal effect in exerting influence on nonlinear behaviors such as bifurcation and chaos (typical phenomena in nonlinear dynamics of nanoscale devices), we have calculated the Lyapunov exponents and bifurcation diagram with and without nonlocal effect, and results shows the nonlocal effect causes the most significant effect as the device is at resonance. This work advances the development of nanowire resonators that are working beyond linear regime.

  10. Nonlocal and nonlinear electrostatics of a dipolar Coulomb fluid.

    Science.gov (United States)

    Sahin, Buyukdagli; Ralf, Blossey

    2014-07-16

    We study a model Coulomb fluid consisting of dipolar solvent molecules of finite extent which generalizes the point-like dipolar Poisson-Boltzmann model (DPB) previously introduced by Coalson and Duncan (1996 J. Phys. Chem. 100 2612) and Abrashkin et al (2007 Phys. Rev. Lett. 99 077801). We formulate a nonlocal Poisson-Boltzmann equation (NLPB) and study both linear and nonlinear dielectric response in this model for the case of a single plane geometry. Our results shed light on the relevance of nonlocal versus nonlinear effects in continuum models of material electrostatics.

  11. Propagation of hypergeometric Gaussian beams in strongly nonlocal nonlinear media

    Science.gov (United States)

    Tang, Bin; Bian, Lirong; Zhou, Xin; Chen, Kai

    2018-01-01

    Optical vortex beams have attracted lots of interest due to its potential application in image processing, optical trapping and optical communications, etc. In this work, we theoretically and numerically investigated the propagation properties of hypergeometric Gaussian (HyGG) beams in strongly nonlocal nonlinear media. Based on the Snyder-Mitchell model, analytical expressions for propagation of the HyGG beams in strongly nonlocal nonlinear media were obtained. The influence of input power and optical parameters on the evolutions of the beam width and radius of curvature is illustrated, respectively. The results show that the beam width and radius of curvature of the HyGG beams remain invariant, like a soliton when the input power is equal to the critical power. Otherwise, it varies periodically like a breather, which is the result of competition between the beam diffraction and nonlinearity of the medium.

  12. Conformal symmetry and nonlinear extensions of nonlocal gravity

    CERN Document Server

    Cusin, Giulia; Maggiore, Michele; Mancarella, Michele

    2016-01-01

    We study two nonlinear extensions of the nonlocal $R\\,\\Box^{-2}R$ gravity theory. We extend this theory in two different ways suggested by conformal symmetry, either replacing $\\Box^{-2}$ with $(-\\Box + R/6)^{-2}$, which is the operator that enters the action for a conformally-coupled scalar field, or replacing $\\Box^{-2}$ with the inverse of the Paneitz operator, which is a four-derivative operator that enters in the effective action induced by the conformal anomaly. We show that the former modification gives an interesting and viable cosmological model, with a dark energy equation of state today $w_{\\rm DE}\\simeq -1.01$, which very closely mimics $\\Lambda$CDM and evolves asymptotically into a de Sitter solution. The model based on the Paneitz operator seems instead excluded by the comparison with observations. We also review some issues about the causality of nonlocal theories, and we point out that these nonlocal models can be modified so to nicely interpolate between Starobinski inflation in the primordia...

  13. Modulational instability, solitons and beam propagation in spatially nonlocal nonlinear media

    International Nuclear Information System (INIS)

    Krolikowski, W; Bang, O; Nikolov, N I; Neshev, D; Wyller, J; Rasmussen, J J; Edmundson, D

    2004-01-01

    We present an overview of recent advances in the understanding of optical beams in nonlinear media with a spatially nonlocal nonlinear response. We discuss the impact of nonlocality on the modulational instability of plane waves, the collapse of finite-size beams, and the formation and interaction of spatial solitons

  14. Modulation instability, solitons and beam propagation in spatially nonlocal nonlinear media

    DEFF Research Database (Denmark)

    Krolikowski, Wieslaw; Bang, Ole; Nikolov, Nikola Ivanov

    2004-01-01

    We present an overview of recent advances in the understanding of optical beams in nonlinear media with a spatially nonlocal nonlinear response. We discuss the impact of nonlocality on the modulational instability of plane waves, the collapse of finite-size beams, and the formation and interactio...... of spatial solitons....

  15. Induced modulation instability and recurrence in nonlocal nonlinear media

    Energy Technology Data Exchange (ETDEWEB)

    Beeckman, J; Neyts, K [Liquid Crystals and Photonics Group, Department of Electronics and Information Systems, Ghent University, Sint-Pietersnieuwstraat 41, 9000 Gent (Belgium); Haelterman, M [Service d' optique et acoustique, Universite libre de Bruxelles CP 194/5, 50 avenue F D Roosevelt, 1050 Bruxelles (Belgium)], E-mail: jeroen.beeckman@elis.ugent.be

    2008-03-28

    The long-term behaviour of spatial modulation instability in nonlocal nonlinear Kerr media is studied theoretically and numerically. Seeding the modulation instability with a periodic modulation leads to an energy transfer to higher-order modes and the long-term behaviour of the system shows the Fermi-Pasta-Ulam recurrence. For large spatial frequencies, close to the cut-off frequency, the stable solution can be found analytically. The propagation with an initial state different from the stable solution results in a propagation circling around the stable point. For general frequencies, the calculation of the stable point is performed numerically. Comparison of the calculations with earlier reported experimental results in nematic liquid crystals shows a satisfactory agreement.

  16. Nonlocal and nonlinear dispersion in a nonlinear Schrodinger-type equation: exotic solitons and short-wavelength instabilities

    DEFF Research Database (Denmark)

    Oster, Michael; Gaididei, Yuri B.; Johansson, Magnus

    2004-01-01

    We study the continuum limit of a nonlinear Schrodinger lattice model with both on-site and inter-site nonlinearities, describing weakly coupled optical waveguides or Bose-Einstein condensates. The resulting continuum nonlinear Schrodinger-type equation includes both nonlocal and nonlinear...

  17. Existence of Solutions of Abstract Nonlinear Mixed Functional Integrodifferential equation with nonlocal conditions

    Directory of Open Access Journals (Sweden)

    Dhakne Machindra B.

    2017-04-01

    Full Text Available In this paper we discuss the existence of mild and strong solutions of abstract nonlinear mixed functional integrodifferential equation with nonlocal condition by using Sadovskii’s fixed point theorem and theory of fractional power of operators.

  18. Stability of two-dimensional spatial solitons in nonlocal nonlinear media

    DEFF Research Database (Denmark)

    Skupin, S.; Bang, Ole; Edmundson, D.

    2006-01-01

    We discuss the existence and stability of two-dimensional solitons in media with spatially nonlocal nonlinear response. We show that such systems, which include thermal nonlinearity and dipolar Bose-Einstein condensates, may support a variety of stationary localized structures, including rotating...... dipole solitons. We also demonstrate that the stability of these structures critically depends on the spatial profile of the nonlocal response function....

  19. 2016 CIME Course on Nonlocal and Nonlinear Diffusions and Interactions : New Methods and Directions

    CERN Document Server

    Grillo, Gabriele

    2017-01-01

    Presenting a selection of topics in the area of nonlocal and nonlinear diffusions, this book places a particular emphasis on new emerging subjects such as nonlocal operators in stationary and evolutionary problems and their applications, swarming models and applications to biology and mathematical physics, and nonlocal variational problems. The authors are some of the most well-known mathematicians in this innovative field, which is presently undergoing rapid development. The intended audience includes experts in elliptic and parabolic equations who are interested in extending their expertise to the nonlinear setting, as well as Ph.D. or postdoctoral students who want to enter into the most promising research topics in the field.

  20. Controllable diffraction of Gaussian beams with initial cross phase in nonlocal nonlinear media

    Science.gov (United States)

    Liang, Guo; Yang, Zhen-Jun

    2018-03-01

    An exact Gaussian beam solution with initial cross phase in nonlocal nonlinear media is presented in the strongly nonlocal limit. It is found that both the diffraction properties and the ellipticity of Gaussian beams closely depend on the cross-phase-front curvature. Because of the experimental controllability of the cross-phase-front curvature, the theoretical results pave the way to beam shaping in experiments.

  1. On displacement based non-local models for non-linear vibrations of thin nano plates

    Directory of Open Access Journals (Sweden)

    Chuaqui Tomás R. C.

    2018-01-01

    Full Text Available This paper addresses the formulation of displacement based, non-linear, plate models adopting Eringen's non-local elasticity, to study the modes of vibration of thin, nano plates. Plate models governed by ordinary differential equations of motion with generalized displacements as unknowns have some advantages over mixed type formulations, but difficulties arise in the development of such non-linear models when non-local effects are taken into account. To circumvent those difficulties, approximations of debatable justification can be imposed. Different approximations are discussed here and the accuracy of the best non-local, non-linear displacement based model achieved is put to test, by carrying out comparisons with a model based on Airy’s stress function.

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

    Directory of Open Access Journals (Sweden)

    A. H. Bhrawy

    2014-01-01

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

  3. Existence of solutions for quasistatic problems of unilateral contact with nonlocal friction for nonlinear elastic materials

    Directory of Open Access Journals (Sweden)

    Alain Mignot

    2005-09-01

    Full Text Available This paper shows the existence of a solution of the quasi-static unilateral contact problem with nonlocal friction law for nonlinear elastic materials. We set up a variational incremental problem which admits a solution, when the friction coefficient is small enough, and then by passing to the limit with respect to time we obtain a solution.

  4. Interaction trajectory of solitons in nonlinear media with an arbitrary degree of nonlocality

    International Nuclear Information System (INIS)

    Dai, Zhiping; Yang, Zhenjun; Ling, Xiaohui; Zhang, Shumin; Pang, Zhaoguang

    2016-01-01

    The interaction trajectory of solitons in nonlocal nonlinear media is investigated. A simple differential equation describing the interaction trajectories is derived based on the light ray equation. Numerical calculations are carried out to illustrate the interaction trajectories with different parameters. The results show that the degree of nonlocality greatly affects the interaction of solitons. For a strongly nonlocal case, the interaction trajectory can be described by a cosine function. Analytical expressions describing the trajectory and the oscillation period are obtained. For generally and weakly nonlocal cases, the interaction trajectories still oscillate periodically, however it is no longer sinusoidal and the oscillation period increases with the nonlocal degree decreasing. In addition, the trajectory of two solitons launched with a relative angle at the entrance plane is investigated. It is found that there exists a critical angle. When the initial relative angle is larger than the critical angle, the two solitons do not collide on propagation. The influence of the degree of nonlocality on the critical angle is also discussed.

  5. Construction of local and non-local conservation laws for non-linear field equations

    International Nuclear Information System (INIS)

    Vladimirov, V.S.; Volovich, I.V.

    1984-08-01

    A method of constructing conserved currents for non-linear field equations is presented. More explicitly for non-linear equations, which can be derived from compatibility conditions of some linear system with a parameter, a procedure of obtaining explicit expressions for local and non-local currents is developed. Some examples such as the classical Heisenberg spin chain and supersymmetric Yang-Mills theory are considered. (author)

  6. Inverse scattering transform for the nonlocal nonlinear Schrödinger equation with nonzero boundary conditions

    Science.gov (United States)

    Ablowitz, Mark J.; Luo, Xu-Dan; Musslimani, Ziad H.

    2018-01-01

    In 2013, a new nonlocal symmetry reduction of the well-known AKNS (an integrable system of partial differential equations, introduced by and named after Mark J. Ablowitz, David J. Kaup, and Alan C. Newell et al. (1974)) scattering problem was found. It was shown to give rise to a new nonlocal PT symmetric and integrable Hamiltonian nonlinear Schrödinger (NLS) equation. Subsequently, the inverse scattering transform was constructed for the case of rapidly decaying initial data and a family of spatially localized, time periodic one-soliton solutions was found. In this paper, the inverse scattering transform for the nonlocal NLS equation with nonzero boundary conditions at infinity is presented in four different cases when the data at infinity have constant amplitudes. The direct and inverse scattering problems are analyzed. Specifically, the direct problem is formulated, the analytic properties of the eigenfunctions and scattering data and their symmetries are obtained. The inverse scattering problem, which arises from a novel nonlocal system, is developed via a left-right Riemann-Hilbert problem in terms of a suitable uniformization variable and the time dependence of the scattering data is obtained. This leads to a method to linearize/solve the Cauchy problem. Pure soliton solutions are discussed, and explicit 1-soliton solution and two 2-soliton solutions are provided for three of the four different cases corresponding to two different signs of nonlinearity and two different values of the phase difference between plus and minus infinity. In another case, there are no solitons.

  7. The algebra of non-local charges in non-linear sigma models

    International Nuclear Information System (INIS)

    Abdalla, E.; Abdalla, M.C.B.; Brunelli, J.C.; Zadra, A.

    1994-01-01

    It is derived the complete Dirac algebra satisfied by non-local charges conserved in non-linear sigma models. Some examples of calculation are given for the O(N) symmetry group. The resulting algebra corresponds to a saturated cubic deformation (with only maximum order terms) of the Kac-Moody algebra. The results are generalized for when a Wess-Zumino term be present. In that case the algebra contains a minor order correction (sub-saturation). (author). 1 ref

  8. Traveling waves in a delayed SIR model with nonlocal dispersal and nonlinear incidence

    Science.gov (United States)

    Zhang, Shou-Peng; Yang, Yun-Rui; Zhou, Yong-Hui

    2018-01-01

    This paper is concerned with traveling waves of a delayed SIR model with nonlocal dispersal and a general nonlinear incidence. The existence and nonexistence of traveling waves of the system are established respectively by Schauder's fixed point theorem and two-sided Laplace transform. It is also shown that the spread speed c is influenced by the dispersal rate of the infected individuals and the delay τ.

  9. Nonlocal Symmetries to Systems of Nonlinear Diffusion Equations

    International Nuclear Information System (INIS)

    Qu Changzheng; Kang Jing

    2008-01-01

    In this paper, we study potential symmetries to certain systems of nonlinear diffusion equations. Those systems have physical applications in soil science, mathematical biology, and invariant curve flows in R 3 . Lie point symmetries of the potential system, which cannot be projected to vector fields of the given dependent and independent variables, yield potential symmetries. The class of the system that admits potential symmetries is expanded.

  10. Fokker-Planck-Kolmogorov equation with nonlocal nonlinearity in quasiclassical approximation

    CERN Document Server

    Trifonov, A Yu

    2002-01-01

    The scheme of plotting the quasiclassically concentrated solutions of the Fokker-Planck-Kolmogorov (FPK) equation with nonlocal nonlinearity is presented on the basis of the WKB-Maslov complex method. The solutions of Cauchy problem for this equation, formal asymptotic ones by the D, D -> 0 small parameters, are plotted with the O(D sup 3 sup / sup 2) exponential accuracy. The Hamilton-Erenfest equation system (the system of equations for the medium and centered moments), derived in this work, plays an important role by plotting such solutions. The approximated Green function is plotted in the class of the FPK quasiclassically concentrated solutions and the superposition nonlinear principle is formulated

  11. The algebra of non-local charges in non-linear sigma models

    CERN Document Server

    Abdalla, Elcio; Brunelli, J C; Zadra, Ayrton

    1994-01-01

    We obtain the exact Dirac algebra obeyed by the conserved non-local charges in bosonic non-linear sigma models. Part of the computation is specialized for a symmetry group $O(N)$. As it turns out the algebra corresponds to a cubic deformation of the Kac-Moody algebra. The non-linear terms are computed in closed form. In each Dirac bracket we only find highest order terms (as explained in the paper), defining a saturated algebra. We generalize the results for the presence of a Wess-Zumino term. The algebra is very similar to the previous one, containing now a calculable correction of order one unit lower.

  12. A Sound Processor for Cochlear Implant Using a Simple Dual Path Nonlinear Model of Basilar Membrane

    OpenAIRE

    Kim, Kyung Hwan; Choi, Sung Jin; Kim, Jin Ho

    2013-01-01

    We propose a new active nonlinear model of the frequency response of the basilar membrane in biological cochlea called the simple dual path nonlinear (SDPN) model and a novel sound processing strategy for cochlear implants (CIs) based upon this model. The SDPN model was developed to utilize the advantages of the level-dependent frequency response characteristics of the basilar membrane for robust formant representation under noisy conditions. In comparison to the dual resonance nonlinear mode...

  13. Imperfection Sensitivity of Nonlinear Vibration of Curved Single-Walled Carbon Nanotubes Based on Nonlocal Timoshenko Beam Theory

    Directory of Open Access Journals (Sweden)

    Iman Eshraghi

    2016-09-01

    Full Text Available Imperfection sensitivity of large amplitude vibration of curved single-walled carbon nanotubes (SWCNTs is considered in this study. The SWCNT is modeled as a Timoshenko nano-beam and its curved shape is included as an initial geometric imperfection term in the displacement field. Geometric nonlinearities of von Kármán type and nonlocal elasticity theory of Eringen are employed to derive governing equations of motion. Spatial discretization of governing equations and associated boundary conditions is performed using differential quadrature (DQ method and the corresponding nonlinear eigenvalue problem is iteratively solved. Effects of amplitude and location of the geometric imperfection, and the nonlocal small-scale parameter on the nonlinear frequency for various boundary conditions are investigated. The results show that the geometric imperfection and non-locality play a significant role in the nonlinear vibration characteristics of curved SWCNTs.

  14. Approximate controllability of Sobolev type fractional stochastic nonlocal nonlinear differential equations in Hilbert spaces

    Directory of Open Access Journals (Sweden)

    Mourad Kerboua

    2014-12-01

    Full Text Available We introduce a new notion called fractional stochastic nonlocal condition, and then we study approximate controllability of class of fractional stochastic nonlinear differential equations of Sobolev type in Hilbert spaces. We use Hölder's inequality, fixed point technique, fractional calculus, stochastic analysis and methods adopted directly from deterministic control problems for the main results. A new set of sufficient conditions is formulated and proved for the fractional stochastic control system to be approximately controllable. An example is given to illustrate the abstract results.

  15. Analytical modeling of soliton interactions in a nonlocal nonlinear medium analogous to gravitational force

    Science.gov (United States)

    Zeng, Shihao; Chen, Manna; Zhang, Ting; Hu, Wei; Guo, Qi; Lu, Daquan

    2018-01-01

    We illuminate an analytical model of soliton interactions in lead glass by analogizing to a gravitational force system. The orbits of spiraling solitons under a long-range interaction are given explicitly and demonstrated to follow Newton's second law of motion and the Binet equation by numerical simulations. The condition for circular orbits is obtained and the oscillating orbits are proved not to be closed. We prove the analogy between the nonlocal nonlinear optical system and gravitational system and specify the quantitative relation of the quantity between the two models.

  16. Nonlocal incoherent solitons

    DEFF Research Database (Denmark)

    Krolikowski, Wieslaw; Bang, Ole; Wyller, John

    2004-01-01

    We investigate the propagation of partially coherent beams in spatially nonlocal nonlinear media with a logarithmic type of nonlinearity. We derive analytical formulas for the evolution of the beam parameters and conditions for the formation of nonlocal incoherent solitons....

  17. Closed-form nonlinear frequency of flexoelectric nanobeams with surface and nonlocal effects under closed circuit electric field

    Science.gov (United States)

    Barati, Mohammad Reza

    2018-02-01

    Nonlocal and surface effects on nonlinear vibration characteristics of a flexoelectric nanobeams under magnetic field are examined. Eringen’s nonlocal elasticity as well as surface elasticity theories are employed to describe the size-dependency of the flexoelectric nanobeam. Also, flexoelectricity is an important size-dependent phenomena for piezoelectric structures at nanoscale, related to the strain gradient-electric polarization coupling. After the derivation of governing equation via Hamilton’s principle, Galerkin method is employed to satisfy boundary conditions. Also, analytical procedures are implemented to obtain the closed-form nonlinear frequency of flexoelectric nanobeam. It is showed that magnetic field intensity, flexoelectric parameter, nonlocal parameter, elastic foundation and applied voltage on the top surface of the nanobeam have great influences on nonlinear vibration frequency.

  18. The algebra of non-local charges in non-linear sigma models

    International Nuclear Information System (INIS)

    Abdalla, E.; Abdalla, M.C.B.; Brunelli, J.C.; Zadra, A.

    1993-07-01

    We obtain the exact Dirac algebra obeyed by the conserved non-local charges in bosonic non-linear sigma models. Part of the computation is specialized for a symmetry group O(N). As it turns out the algebra corresponds to a cubic deformation of the Kac-Moody algebra. The non-linear terms are computed in closed form. In each Dirac bracket we only find highest order terms (as explained in the paper), defining a saturated algebra. We generalize the results for the presence of a Wess-Zumino term. The algebra is very similar to the previous one, containing now a calculable correction of order one unit lower. (author). 22 refs, 5 figs

  19. Rational solitons in the parity-time-symmetric nonlocal nonlinear Schrödinger model

    International Nuclear Information System (INIS)

    Li Min; Xu Tao; Meng Dexin

    2016-01-01

    In this paper, via the generalized Darboux transformation, rational soliton solutions are derived for the parity-time-symmetric nonlocal nonlinear Schrödinger (NLS) model with the defocusing-type nonlinearity. We find that the first-order solution can exhibit the elastic interactions of rational antidark-antidark, dark-antidark, and antidark-dark soliton pairs on a continuous wave background, but there is no phase shift for the interacting solitons. Also, we discuss the degenerate case in which only one rational dark or antidark soliton survives. Moreover, we reveal that the second-order rational solution displays the interactions between two solitons with combined-peak-valley structures in the near-field regions, but each interacting soliton vanishes or evolves into a rational dark or antidark soliton as |z| → ∞. In addition, we numerically examine the stability of the first- and second-order rational soliton solutions. (author)

  20. Z-scan and spatial self-phase modulation of a Gaussian beam in a thin nonlocal nonlinear media

    International Nuclear Information System (INIS)

    Garcia Ramirez, E V; Arroyo Carrasco, M L; Mendez Otero, M M; Reynoso Lara, E; Chavez-Cerda, S; Iturbe Castillo, M D

    2011-01-01

    Considering that the nonlinear photoinduced phase shift to a Gaussian beam in a thin sample of nonlocal nonlinear media can be modeled as a Gaussian function to some real power the far-field can be calculated using the Fraunhofer integral. In this paper we calculate numerically this integral to obtain the on-axis intensity in a Z-scan experiment or the intensity pattern in a self-phase modulation experiment. Experimental results of samples under cw illumination are fitted using the model with a good correspondence between experimental and numerical results. The model presented is adequate to describe samples with any magnitude of the maximum nonlinear photoinduced phase shift of purely refractive local or nonlocal nonlinear thin media

  1. Development an efficient calibrated nonlocal plate model for nonlinear axial instability of zirconia nanosheets using molecular dynamics simulation.

    Science.gov (United States)

    Sahmani, S; Fattahi, A M

    2017-08-01

    New ceramic materials containing nanoscaled crystalline phases create a main object of scientific interest due to their attractive advantages such as biocompatibility. Zirconia as a transparent glass ceramic is one of the most useful binary oxides in a wide range of applications. In the present study, a new size-dependent plate model is constructed to predict the nonlinear axial instability characteristics of zirconia nanosheets under axial compressive load. To accomplish this end, the nonlocal continuum elasticity of Eringen is incorporated to a refined exponential shear deformation plate theory. A perturbation-based solving process is put to use to derive explicit expressions for nonlocal equilibrium paths of axial-loaded nanosheets. After that, some molecular dynamics (MD) simulations are performed for axial instability response of square zirconia nanosheets with different side lengths, the results of which are matched with those of the developed nonlocal plate model to capture the proper value of nonlocal parameter. It is demonstrated that the calibrated nonlocal plate model with nonlocal parameter equal to 0.37nm has a very good capability to predict the axial instability characteristics of zirconia nanosheets, the accuracy of which is comparable with that of MD simulation. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. The effects of relativistic and non-local non-linearities on modulational instabilities in non-uniform plasma

    International Nuclear Information System (INIS)

    Mohamed, B.F.; El-Shorbagy, Kh.H.

    2000-01-01

    A general detailed analysis for the nonlinear generation of localized fields due to the existence of a strong pump field inside the non-uniform plasma has been considered. We have taken into account the effects of relativistic and non-local nonlinearities on the structure of plasma resonance region. The nonlinear Schrodinger equation described the localized fields are investigated. Besides, the generalized dispersion relation is obtained to study the modulational instabilities in different cases. Keywords: Wave-plasma interaction, Nonlinear effects, Modulation instabilities

  3. Identification of the population density of a species model with nonlocal diffusion and nonlinear reaction

    Science.gov (United States)

    Tuan, Nguyen Huy; Van Au, Vo; Khoa, Vo Anh; Lesnic, Daniel

    2017-05-01

    The identification of the population density of a logistic equation backwards in time associated with nonlocal diffusion and nonlinear reaction, motivated by biology and ecology fields, is investigated. The diffusion depends on an integral average of the population density whilst the reaction term is a global or local Lipschitz function of the population density. After discussing the ill-posedness of the problem, we apply the quasi-reversibility method to construct stable approximation problems. It is shown that the regularized solutions stemming from such method not only depend continuously on the final data, but also strongly converge to the exact solution in L 2-norm. New error estimates together with stability results are obtained. Furthermore, numerical examples are provided to illustrate the theoretical results.

  4. The effect of cochlear nonlinearities on binaural masking level differences

    DEFF Research Database (Denmark)

    Le Goff, Nicolas; Kohlrausch, Armin

    Background The binaural masking level difference (BMLD) has been shown to be constant (10−15dB) for masker spectrum levels from 70dB/Hz down to 30−40dB/Hz and to gradually decrease with lower levels (McFadden, 1968; Hall and Harvey, 1984). The decrease at low levels was larger in an asymmetric...... that the difference in BMLD between the symmetric and the two asymmetric conditions is constant, in line with the experimental data. Conclusion A model was proposed to account for the effect of level asymmetry on BMLD. The modeling results suggest that cochlear nonlinearites affect the analysis of binaural cues a  at...

  5. Nonlinear primary resonance of micro/nano-beams made of nanoporous biomaterials incorporating nonlocality and strain gradient size dependency

    Science.gov (United States)

    Sahmani, S.; Aghdam, M. M.

    2018-03-01

    A wide range of biological applications such as drug delivery, biosensors and hemodialysis can be provided by nanoporous biomaterials due to their uniform pore size as well as considerable pore density. In the current study, the size dependency in the nonlinear primary resonance of micro/nano-beams made of nanoporous biomaterials is anticipated. To accomplish this end, a refined truncated cube is introduced to model the lattice structure of nanoporous biomaterial. Accordingly, analytical expressions for the mechanical properties of material are derived as functions of pore size. After that, based upon a nonlocal strain gradient beam model, the size-dependent nonlinear Duffing type equation of motion is constructed. The Galerkin technique together with the multiple time-scales method is employed to obtain the nonlocal strain gradient frequency-response and amplitude-response related to the nonlinear primary resonance of a micro/nano-beam made of the nanoporous biomaterial with different pore sizes. It is indicated that the nonlocality causes to decrease the response amplitudes associated with the both bifurcation points of the jump phenomenon, while the strain gradient size dependency causes to increase them. Also, it is found that increasing the pore size leads to enhance the nonlinearity, so the maximum deflection of response occurs at higher excitation frequency.

  6. Studies on nonlocal optical nonlinearity of Sr–CuO–polyvinyl alcohol nanocomposite thin films

    International Nuclear Information System (INIS)

    Tamgadge, Y.S.; Talwatkar, S.S.; Sunatkari, A.L.; Pahurkar, V.G.; Muley, G.G.

    2015-01-01

    Thermally induced nonlocal nonlinear optical properties of strontium (Sr) doped CuO-polyvinyl alcohol (PVA) nanocomposite thin films under continuous wave Helium–Neon laser illumination are investigated by single beam Z-scan method. Undoped and Sr doped CuO nanoparticles (NPs) using L-arginine as surface modifying agent have been synthesized by wet chemical method and their thin films with PVA as host matrix have been obtained by spin coating technique. Structure, morphology and purity of prepared CuO NPs and thin films have been studied by X-ray diffraction, high-resolution transmission electron microscopy, field emission scanning electron microscopy and energy dispersive X-ray absorption spectroscopy. Fourier transform infra-red spectrum attests the role of L-arginine as surface modifier and ultraviolet–visible absorption studies reveal that the excitonic absorption wavelengths are blue shifted for strontium doped CuO NPs. Sr doped CuO NPs with average particle size of 7 nm and calculated optical band gap up to 2.54 eV have been reported. All Sr doped CuO–PVA nanocomposite thin films show enhanced nonlinear refraction and absorption best suited for optical limiting applications. Observed effects have been attributed to thermal lensing effect. - Highlights: • Pure and strontium doped CuO–polyvinyl alcohol nanocomposite thin films are prepared. • Z-scan studies of thin films are performed under continuous wave helium–neon laser. • Enhanced values of third order nonlinear optical coefficients are obtained for all films. • Thermally induced self-defocusing and reverse saturable absorption have been discussed.

  7. Studies on nonlocal optical nonlinearity of Sr–CuO–polyvinyl alcohol nanocomposite thin films

    Energy Technology Data Exchange (ETDEWEB)

    Tamgadge, Y.S. [Department of Physics, Mahatma Fule Arts, Commerce and S C Science Mahavidyalaya, Warud, Dist. Amravati (MS), 444906 (India); Talwatkar, S.S. [Department of Physics, D K Marathe and N G Acharya College, Chembur, Mumbai (MS) 440071 (India); Sunatkari, A.L. [Department of Physics, Siddharth College of Arts, Science and Commerce, Fort, Mumbai (MS) 440001 (India); Pahurkar, V.G. [Department of Physics, Sant Gadge Baba Amravati University, Amravati (MS), 444602 (India); Muley, G.G., E-mail: gajananggm@yahoo.co.in [Department of Physics, Sant Gadge Baba Amravati University, Amravati (MS), 444602 (India)

    2015-11-30

    Thermally induced nonlocal nonlinear optical properties of strontium (Sr) doped CuO-polyvinyl alcohol (PVA) nanocomposite thin films under continuous wave Helium–Neon laser illumination are investigated by single beam Z-scan method. Undoped and Sr doped CuO nanoparticles (NPs) using L-arginine as surface modifying agent have been synthesized by wet chemical method and their thin films with PVA as host matrix have been obtained by spin coating technique. Structure, morphology and purity of prepared CuO NPs and thin films have been studied by X-ray diffraction, high-resolution transmission electron microscopy, field emission scanning electron microscopy and energy dispersive X-ray absorption spectroscopy. Fourier transform infra-red spectrum attests the role of L-arginine as surface modifier and ultraviolet–visible absorption studies reveal that the excitonic absorption wavelengths are blue shifted for strontium doped CuO NPs. Sr doped CuO NPs with average particle size of 7 nm and calculated optical band gap up to 2.54 eV have been reported. All Sr doped CuO–PVA nanocomposite thin films show enhanced nonlinear refraction and absorption best suited for optical limiting applications. Observed effects have been attributed to thermal lensing effect. - Highlights: • Pure and strontium doped CuO–polyvinyl alcohol nanocomposite thin films are prepared. • Z-scan studies of thin films are performed under continuous wave helium–neon laser. • Enhanced values of third order nonlinear optical coefficients are obtained for all films. • Thermally induced self-defocusing and reverse saturable absorption have been discussed.

  8. A Sound Processor for Cochlear Implant Using a Simple Dual Path Nonlinear Model of Basilar Membrane

    Directory of Open Access Journals (Sweden)

    Kyung Hwan Kim

    2013-01-01

    Full Text Available We propose a new active nonlinear model of the frequency response of the basilar membrane in biological cochlea called the simple dual path nonlinear (SDPN model and a novel sound processing strategy for cochlear implants (CIs based upon this model. The SDPN model was developed to utilize the advantages of the level-dependent frequency response characteristics of the basilar membrane for robust formant representation under noisy conditions. In comparison to the dual resonance nonlinear model (DRNL which was previously proposed as an active nonlinear model of the basilar membrane, the SDPN model can reproduce similar level-dependent frequency responses with a much simpler structure and is thus better suited for incorporation into CI sound processors. By the analysis of dominant frequency component, it was confirmed that the formants of speech are more robustly represented after frequency decomposition by the nonlinear filterbank using SDPN, compared to a linear bandpass filter array which is used in conventional strategies. Acoustic simulation and hearing experiments in subjects with normal hearing showed that the proposed strategy results in better syllable recognition under speech-shaped noise compared to the conventional strategy based on fixed linear bandpass filters.

  9. The effect of non-local higher order stress to predict the nonlinear vibration behavior of carbon nanotube conveying viscous nanoflow

    Energy Technology Data Exchange (ETDEWEB)

    Mohammadimehr, M., E-mail: mmohammadimehr@kashanu.ac.ir [Department of Solid Mechanics, Faculty of Mechanical Engineering, University of Kashan, P.O. Box: 87317-53153, Kashan (Iran, Islamic Republic of); Mohammadi-Dehabadi, A.A. [Department of Solid Mechanics, Faculty of Mechanical Engineering, University of Kashan, P.O. Box: 87317-53153, Kashan (Iran, Islamic Republic of); Department of Mechanical Engineering, Iran University of Science and Technology, Narmak, Tehran (Iran, Islamic Republic of); Maraghi, Z. Khoddami [Department of Solid Mechanics, Faculty of Mechanical Engineering, University of Kashan, P.O. Box: 87317-53153, Kashan (Iran, Islamic Republic of)

    2017-04-01

    In this research, the effect of non-local higher order stress on the nonlinear vibration behavior of carbon nanotube conveying viscous nanoflow resting on elastic foundation is investigated. Physical intuition reveals that increasing nanoscale stress leads to decrease the stiffness of nanostructure which firstly established by Eringen's non-local elasticity theory (previous nonlocal method) while many of papers have concluded otherwise at microscale based on modified couple stress, modified strain gradient theories and surface stress effect. The non-local higher order stress model (new nonlocal method) is used in this article that has been studied by few researchers in other fields and the results from the present study show that the trend of the new nonlocal method and size dependent effect including modified couple stress theory is the same. In this regard, the nonlinear motion equations are derived using a variational principal approach considering essential higher-order non-local terms. The surrounded elastic medium is modeled by Pasternak foundation to increase the stability of system where the fluid flow may cause system instability. Effects of various parameters such as non-local parameter, elastic foundation coefficient, and fluid flow velocity on the stability and dimensionless natural frequency of nanotube are investigated. The results of this research show that the small scale parameter based on higher order stress help to increase the natural frequency which has been approved by other small scale theories such as strain gradient theory, modified couple stress theory and experiments, and vice versa for previous nonlocal method. This study may be useful to measure accurately the vibration characteristics of nanotubes conveying viscous nanoflow and to design nanofluidic devices for detecting blood Glucose.

  10. Unique solvability of a non-linear non-local boundary-value problem for systems of non-linear functional differential equations

    Czech Academy of Sciences Publication Activity Database

    Dilna, N.; Rontó, András

    2010-01-01

    Roč. 60, č. 3 (2010), s. 327-338 ISSN 0139-9918 R&D Projects: GA ČR(CZ) GA201/06/0254 Institutional research plan: CEZ:AV0Z10190503 Keywords : non-linear boundary value-problem * functional differential equation * non-local condition * unique solvability * differential inequality Subject RIV: BA - General Mathematics Impact factor: 0.316, year: 2010 http://link.springer.com/article/10.2478%2Fs12175-010-0015-9

  11. Plasmonic modes in nanowire dimers: A study based on the hydrodynamic Drude model including nonlocal and nonlinear effects

    Science.gov (United States)

    Moeferdt, Matthias; Kiel, Thomas; Sproll, Tobias; Intravaia, Francesco; Busch, Kurt

    2018-02-01

    A combined analytical and numerical study of the modes in two distinct plasmonic nanowire systems is presented. The computations are based on a discontinuous Galerkin time-domain approach, and a fully nonlinear and nonlocal hydrodynamic Drude model for the metal is utilized. In the linear regime, these computations demonstrate the strong influence of nonlocality on the field distributions as well as on the scattering and absorption spectra. Based on these results, second-harmonic-generation efficiencies are computed over a frequency range that covers all relevant modes of the linear spectra. In order to interpret the physical mechanisms that lead to corresponding field distributions, the associated linear quasielectrostatic problem is solved analytically via conformal transformation techniques. This provides an intuitive classification of the linear excitations of the systems that is then applied to the full Maxwell case. Based on this classification, group theory facilitates the determination of the selection rules for the efficient excitation of modes in both the linear and nonlinear regimes. This leads to significantly enhanced second-harmonic generation via judiciously exploiting the system symmetries. These results regarding the mode structure and second-harmonic generation are of direct relevance to other nanoantenna systems.

  12. Application of Homotopy Analysis Method for the Pull-In and Nonlinear Vibration Analysis of Nanobeams Using a Nonlocal Euler-Bernoulli Beam Model

    Science.gov (United States)

    Samadani, F.; Moradweysi, P.; Ansari, R.; Hosseini, K.; Darvizeh, A.

    2017-11-01

    In this investigation, the homotopy analysis method (HAM) is utilized for the pull-in and nonlinear vibration analysis of nanobeams based on the stress-driven model (SDM) of nonlocal elasticity theory. The physical properties of nanobeams are assumed not to vary through the thickness. The nonlinear equation of motion and the corresponding boundary condition are derived on the basis of the Euler-Bernoulli beam theory. For the solution purpose, the Galerkin method is employed for reducing the nonlinear partial differential equation to a nonlinear ordinary differential equation in the time domain, and then, the resulting equation is analytically solved using the HAM. In the results section, the influences of different parameters, including nonlocal parameter, electrostatic and intermolecular van der Waals forces and fringing field effect changes on the pull-in and nonlinear vibration response are investigated.

  13. Quantum non-local charges and absence of particle production in the two-dimensional non-linear sigma-model

    International Nuclear Information System (INIS)

    Luescher, M.

    1977-12-01

    Conserved non-local charges are shown to exist in the quantum non-linear sigma-model by a non-perturbative method. They imply the absence of particle production and the 'factorization equations' for the two particle S-matrix, which can then be calculated explicitly. (Auth.)

  14. Some nonlinear and nonlocal Sturm-Liouville problems motivated by the problem of flutter

    Directory of Open Access Journals (Sweden)

    B. P. Belinskiy

    2009-10-01

    Full Text Available We study three internally connected Sturm-Liouville problems for nonlinear ordinary differential equations that are motivated by the problem of aeroelastic instability. Solutions are analyzed and asymptotic results are presented. A numerical study using a development of simple shooting reveals the spectrum and corresponding eigenfunctions.

  15. Existence of Wave Front Solutions of an Integral Differential Equation in Nonlinear Nonlocal Neuronal Network

    Directory of Open Access Journals (Sweden)

    Lijun Zhang

    2014-01-01

    Full Text Available An integral-differential model equation arising from neuronal networks with very general kernel functions is considered in this paper. The kernel functions we study here include pure excitations, lateral inhibition, lateral excitations, and more general synaptic couplings (e.g., oscillating kernel functions. The main goal of this paper is to prove the existence and uniqueness of the traveling wave front solutions. The main idea we apply here is to reduce the nonlinear integral-differential equation into a solvable differential equation and test whether the solution we get is really a wave front solution of the model equation.

  16. Stable rotating dipole solitons in nonlocal media

    DEFF Research Database (Denmark)

    Lopez-Aguayo, Servando; Skupin, Stefan; Desyatnikov, Anton S.

    2006-01-01

    We present the first example of stable rotating two-soliton bound states in nonlinear optical media with nonlocal response. We show that, in contrast to media with local response, nonlocality opens possibilities to generate stable azimuthons.......We present the first example of stable rotating two-soliton bound states in nonlinear optical media with nonlocal response. We show that, in contrast to media with local response, nonlocality opens possibilities to generate stable azimuthons....

  17. A string of Peregrine rogue waves in the nonlocal nonlinear Schrödinger equation with parity-time symmetric self-induced potential

    Science.gov (United States)

    Gupta, Samit Kumar

    2018-03-01

    Dynamic wave localization phenomena draw fundamental and technological interests in optics and photonics. Based on the recently proposed (Ablowitz and Musslimani, 2013) continuous nonlocal nonlinear Schrödinger system with parity-time symmetric Kerr nonlinearity (PTNLSE), a numerical investigation has been carried out for two first order Peregrine solitons as the initial ansatz. Peregrine soliton, as an exact solution to the PTNLSE, evokes a very potent question: what effects does the interaction of two first order Peregrine solitons have on the overall optical field dynamics. Upon numerical computation, we observe the appearance of Kuznetsov-Ma (KM) soliton trains in the unbroken PT-phase when the initial Peregrine solitons are in phase. In the out of phase condition, it shows repulsive nonlinear waves. Quite interestingly, our study shows that within a specific range of the interval factor in the transverse co-ordinate there exists a string of high intensity well-localized Peregrine rogue waves in the PT unbroken phase. We note that the interval factor as well as the transverse shift parameter play important roles in the nonlinear interaction and evolution dynamics of the optical fields. This could be important in developing fundamental understanding of nonlocal non-Hermitian NLSE systems and dynamic wave localization behaviors.

  18. Nonlocal gravity

    CERN Document Server

    Mashhoon, Bahram

    2017-01-01

    Relativity theory is based on a postulate of locality, which means that the past history of the observer is not directly taken into account. This book argues that the past history should be taken into account. In this way, nonlocality---in the sense of history dependence---is introduced into relativity theory. The deep connection between inertia and gravitation suggests that gravity could be nonlocal, and in nonlocal gravity the fading gravitational memory of past events must then be taken into account. Along this line of thought, a classical nonlocal generalization of Einstein's theory of gravitation has recently been developed. A significant consequence of this theory is that the nonlocal aspect of gravity appears to simulate dark matter. According to nonlocal gravity theory, what astronomers attribute to dark matter should instead be due to the nonlocality of gravitation. Nonlocality dominates on the scale of galaxies and beyond. Memory fades with time; therefore, the nonlocal aspect of gravity becomes wea...

  19. On the identification of Hammerstein systems in the presence of an input hysteretic nonlinearity with nonlocal memory: Piezoelectric actuators – an experimental case study

    Energy Technology Data Exchange (ETDEWEB)

    Butcher, Mark; Giustiniani, Alessandro, E-mail: alessandro.giustiniani@cern.ch; Masi, Alessandro

    2016-04-01

    The identification problem of the linear dynamic part of piezo based actuators is addressed in this paper, exploiting the use of binary signals, specifically the pseudo random binary sequences (PRBS). Due to the presence of nonlocal memory hysteretic behavior in piezoelectric active materials, the dependence of the identification results on this strongly nonlinear effect is analyzed and useful guidelines for the design of the PRBS stimulating signal are derived. Moreover, some properties of hysteresis like cancellation and congruency are experimentally analyzed and their effects on the identification process are discussed. Finally, the use of a hysteresis compensation strategy in the identification process is evaluated and discussed.

  20. submitter On the identification of Hammerstein systems in the presence of an input hysteretic nonlinearity with nonlocal memory: Piezoelectric actuators – an experimental case study

    CERN Document Server

    Butcher, Mark; Masi, Alessandro

    2016-01-01

    The identification problem of the linear dynamic part of piezo based actuators is addressed in this paper, exploiting the use of binary signals, specifically the pseudo random binary sequences (PRBS). Due to the presence of nonlocal memory hysteretic behavior in piezoelectric active materials, the dependence of the identification results on this strongly nonlinear effect is analyzed and useful guidelines for the design of the PRBS stimulating signal are derived. Moreover, some properties of hysteresis like cancellation and congruency are experimentally analyzed and their effects on the identification process are discussed. Finally, the use of a hysteresis compensation strategy in the identification process is evaluated and discussed.

  1. Nonlinear time-domain cochlear model for transient stimulation and human otoacoustic emission

    DEFF Research Database (Denmark)

    Verhulst, Sarah; Dau, Torsten; Shera, Christopher A.

    2012-01-01

    This paper describes the implementation and performance of a nonlinear time-domain model of the cochlea for transient stimulation and human otoacoustic emission generation. The nonlinearity simulates compressive growth of measured basilar-membrane impulse responses. The model accounts for reflect......This paper describes the implementation and performance of a nonlinear time-domain model of the cochlea for transient stimulation and human otoacoustic emission generation. The nonlinearity simulates compressive growth of measured basilar-membrane impulse responses. The model accounts...

  2. Third order nonlinear optics in Ag nanocubes: local and nonlocal optical responses as a function of excitation wavelength and particle size.

    Science.gov (United States)

    García Ramírez, E V; Sabinas Hernández, S A; Ramírez Martínez, D; Díaz, G; Reyes Esqueda, J A

    2017-12-11

    Colloidal silver nanocubes in solution were analyzed by the Z-scan technique in the resonant and non-resonant regimes. Three different systems with particle sizes of 56, 99 and 215 nm, and concentrations of 0.378, 0.831 and 0.715 mg/mL, respectively, were obtained by the polyol method. Nonlinear excitation of the samples was performed with laser pulses of 26 ps, at a repetition rate of 10 Hz, and using three different wavelenghts (355, 532 and 1064 nm), exciting only the electronic part of the optical nonlinearity, and avoiding induced thermal loading of the samples. Whenever observable, samples showed saturable absorption for all wavelengths, which was dependent, in general, on concentration and incident intensity. For samples featuring sizes of 55 and 99 nm, saturable absorption could be observed for wavelengths close to their dipolar surface plasmon resonances; while, for samples with sizes of 99 and 215 nm, saturable absorption and positive nonlinear optical refraction (only for size of 215 nm) could be observed at 1064 nm. Besides, for some samples, nonlinear optical response followed the incident intensity profile at wavelengths close to resonance. On the contrary, for wavelengths out of resonance, the nonlinear optical behavior showed to be nonlocal, ie, its profile was narrower than the incident one.

  3. Attraction of nonlocal dark optical solitons

    DEFF Research Database (Denmark)

    Nikolov, Nikola Ivanov; Neshev, Dragomir; Krolikowski, Wieslaw

    2004-01-01

    We study the formation and interaction of spatial dark optical solitons in materials with a nonlocal nonlinear response. We show that unlike in local materials, where dark solitons typically repel, the nonlocal nonlinearity leads to a long-range attraction and formation of stable bound states...

  4. Dark and antidark soliton interactions in the nonlocal nonlinear Schrödinger equation with the self-induced parity-time-symmetric potential.

    Science.gov (United States)

    Li, Min; Xu, Tao

    2015-03-01

    Via the Nth Darboux transformation, a chain of nonsingular localized-wave solutions is derived for a nonlocal nonlinear Schrödinger equation with the self-induced parity-time (PT) -symmetric potential. It is found that the Nth iterated solution in general exhibits a variety of elastic interactions among 2N solitons on a continuous-wave background and each interacting soliton could be the dark or antidark type. The interactions with an arbitrary odd number of solitons can also be obtained under different degenerate conditions. With N=1 and 2, the two-soliton and four-soliton interactions and their various degenerate cases are discussed in the asymptotic analysis. Numerical simulations are performed to support the analytical results, and the stability analysis indicates that the PT-symmetry breaking can also destroy the stability of the soliton interactions.

  5. Mimicking the cochlear amplifier in a cantilever beam using nonlinear velocity feedback control

    International Nuclear Information System (INIS)

    Joyce, Bryan S; Tarazaga, Pablo A

    2014-01-01

    The mammalian cochlea exhibits a nonlinear amplification which allows mammals to detect a large range of sound pressure levels while maintaining high frequency sensitivity. This work seeks to mimic the cochlea’s nonlinear amplification in a mechanical system. A nonlinear, velocity-based feedback control law is applied to a cantilever beam with piezoelectric actuators. The control law reduces the linear viscous damping of the system while introducing a cubic damping term. The result is a system which is positioned close to a Hopf bifurcation. Modelling and experimental results show that the beam with this control law undergoes a one-third amplitude scaling near the resonance frequency and an amplitude-dependent bandwidth. Both behaviors are characteristic of data obtained from the mammalian cochlea. This work could provide insight on the biological cochlea while producing bio-inspired sensors with a large dynamic range and sharp frequency sensitivity. (papers)

  6. Mimicking the cochlear amplifier in a cantilever beam using nonlinear velocity feedback control

    Science.gov (United States)

    Joyce, Bryan S.; Tarazaga, Pablo A.

    2014-07-01

    The mammalian cochlea exhibits a nonlinear amplification which allows mammals to detect a large range of sound pressure levels while maintaining high frequency sensitivity. This work seeks to mimic the cochlea’s nonlinear amplification in a mechanical system. A nonlinear, velocity-based feedback control law is applied to a cantilever beam with piezoelectric actuators. The control law reduces the linear viscous damping of the system while introducing a cubic damping term. The result is a system which is positioned close to a Hopf bifurcation. Modelling and experimental results show that the beam with this control law undergoes a one-third amplitude scaling near the resonance frequency and an amplitude-dependent bandwidth. Both behaviors are characteristic of data obtained from the mammalian cochlea. This work could provide insight on the biological cochlea while producing bio-inspired sensors with a large dynamic range and sharp frequency sensitivity.

  7. Accurate nonlocal theory for cascaded quadratic soliton compression

    DEFF Research Database (Denmark)

    Bache, Morten; Bang, Ole; Moses, Jeffrey

    2007-01-01

    We study soliton compression in bulk quadratic nonlinear materials at 800 nm, where group-velocity mismatch dominates. We develop a nonlocal theory showing that efficient compression depends strongly on characteristic nonlocal time scales related to pulse dispersion....

  8. Non-local effects in kaonic atoms

    International Nuclear Information System (INIS)

    Lutz, M.; Florkowski, W.

    2000-04-01

    Optical potentials with non-local (gradient) terms are used to describe the spectra of kaonic atoms. The strength of the non-local terms is determined from a many-body calculation of the kaon self-energy in nuclear matter. The optical potentials show strong non-linearities in the nucleon density and sizeable non-local terms. We find that the non-local terms are quantitatively important and the results depend strongly on the way the gradient terms are arranged. Phenomenologically successful fits are obtained for p-wave like optical potentials. It is suggested that the microscopic form of the non-local interaction terms is obtained systematically by means of a semi-classical expansion of the nucleus structure. We conclude that a microscopic description of kaonic atom data requires further detailed studies of the microscopic K - nuclear dynamics. (orig.)

  9. Collapse suppression and soliton stabilization through nonlocality in bulk Kerr media

    DEFF Research Database (Denmark)

    Bang, Ole; Chemineau, E. T.; Krolikowski, Wieslaw

    2000-01-01

    We show that self-focusing cannot occur in bulk Kerr media with a nonlocal nonlinear response. We find the stationary solutions and show that nonlocality makes them stable. The results are verified numerically....

  10. Nonlocal Fordy - Kulish Equations on Symmetric Spaces

    OpenAIRE

    Gurses, Metin

    2017-01-01

    We present nonlocal integrable reductions of the Fordy-Kulish system of nonlinear Schrodinger equations and the Fordy system of derivative nonlinear Schrodinger equations on Hermitian symmetric spaces. Examples are given on the symmetric space $\\frac{SU(4)}{SU(2) \\times SU(2)}$.

  11. Observation of two-dimensional nonlocal gap solitons

    DEFF Research Database (Denmark)

    Rasmussen, Per Dalgaard; Bennett, Francis H.; Neshev, Dragomir N.

    2009-01-01

    We demonstrate, both theoretically and experimentally, the existence of nonlocal gap solitons in twodimensional periodic photonic structures with defocusing thermal nonlinearity. We employ liquid-infiltrated photonic crystal fibers and show how the system geometry can modify the effective response...

  12. Cochlear Implants

    Science.gov (United States)

    A cochlear implant is a small, complex electronic device that can help to provide a sense of sound. People who are ... of-hearing can get help from them. The implant consists of two parts. One part sits on ...

  13. Nonlocal gap soliton in liquid infiltrated photonic crystal fibres

    DEFF Research Database (Denmark)

    Bennet, F.H.; Rosberg, C.R.; Rasmussen, Per Dalgaard

    We report on the observation of nonlocal gap solitons in infiltrated photonic crystal fibres. We employ the thermal defocusing nonlinearity of the liquid to study soliton existence and effect of boundaries of the periodic structure.......We report on the observation of nonlocal gap solitons in infiltrated photonic crystal fibres. We employ the thermal defocusing nonlinearity of the liquid to study soliton existence and effect of boundaries of the periodic structure....

  14. Testing nonlocal realism with entangled coherent states

    International Nuclear Information System (INIS)

    Paternostro, Mauro; Jeong, Hyunseok

    2010-01-01

    We investigate the violation of nonlocal realism using entangled coherent states (ECSs) under nonlinear operations and homodyne measurements. We address recently proposed Leggett-type inequalities, including a class of optimized incompatibility inequalities proposed by Branciard et al. [Nature Phys. 4, 681 (2008)], and thoroughly assess the effects of detection inefficiency.

  15. Quantum Nonlocality and Reality

    Science.gov (United States)

    Bell, Mary; Gao, Shan

    2016-09-01

    Preface; Part I. John Stewart Bell: The Physicist: 1. John Bell: the Irish connection Andrew Whitaker; 2. Recollections of John Bell Michael Nauenberg; 3. John Bell: recollections of a great scientist and a great man Gian-Carlo Ghirardi; Part II. Bell's Theorem: 4. What did Bell really prove? Jean Bricmont; 5. The assumptions of Bell's proof Roderich Tumulka; 6. Bell on Bell's theorem: the changing face of nonlocality Harvey R. Brown and Christopher G. Timpson; 7. Experimental tests of Bell inequalities Marco Genovese; 8. Bell's theorem without inequalities: on the inception and scope of the GHZ theorem Olival Freire, Jr and Osvaldo Pessoa, Jr; 9. Strengthening Bell's theorem: removing the hidden-variable assumption Henry P. Stapp; Part III. Nonlocality: Illusions or Reality?: 10. Is any theory compatible with the quantum predictions necessarily nonlocal? Bernard d'Espagnat; 11. Local causality, probability and explanation Richard A. Healey; 12. Bell inequality and many-worlds interpretation Lev Vaidman; 13. Quantum solipsism and non-locality Travis Norsen; 14. Lessons of Bell's theorem: nonlocality, yes; action at a distance, not necessarily Wayne C. Myrvold; 15. Bell non-locality, Hardy's paradox and hyperplane dependence Gordon N. Fleming; 16. Some thoughts on quantum nonlocality and its apparent incompatibility with relativity Shan Gao; 17. A reasonable thing that just might work Daniel Rohrlich; 18. Weak values and quantum nonlocality Yakir Aharonov and Eliahu Cohen; Part IV. Nonlocal Realistic Theories: 19. Local beables and the foundations of physics Tim Maudlin; 20. John Bell's varying interpretations of quantum mechanics: memories and comments H. Dieter Zeh; 21. Some personal reflections on quantum non-locality and the contributions of John Bell Basil J. Hiley; 22. Bell on Bohm Sheldon Goldstein; 23. Interactions and inequality Philip Pearle; 24. Gravitation and the noise needed in objective reduction models Stephen L. Adler; 25. Towards an objective

  16. Single photon and nonlocality

    Indian Academy of Sciences (India)

    critical analysis of the concept of hidden variable used by the authors of [1] shows that the reasoning is not correct. Keywords. Nonlocality; single particle; hidden variables. PACS Nos 03.67.Ba; 03.65.Ta; 32.80.Lg; 07.79.Fc. 1. Introduction. Quantum nonlocality [2] for single particle is a subject of debate since the origin.

  17. Nonlocal teleparallel cosmology.

    Science.gov (United States)

    Bahamonde, Sebastian; Capozziello, Salvatore; Faizal, Mir; Nunes, Rafael C

    2017-01-01

    Even though it is not possible to differentiate general relativity from teleparallel gravity using classical experiments, it could be possible to discriminate between them by quantum gravitational effects. These effects have motivated the introduction of nonlocal deformations of general relativity, and similar effects are also expected to occur in teleparallel gravity. Here, we study nonlocal deformations of teleparallel gravity along with its cosmological solutions. We observe that nonlocal teleparallel gravity (like nonlocal general relativity) is consistent with the present cosmological data obtained by SNe Ia + BAO + CC + [Formula: see text] observations. Along this track, future experiments probing nonlocal effects could be used to test whether general relativity or teleparallel gravity gives the most consistent picture of gravitational interaction.

  18. Nonlocal teleparallel cosmology

    Energy Technology Data Exchange (ETDEWEB)

    Bahamonde, Sebastian [University College London, Department of Mathematics, London (United Kingdom); Capozziello, Salvatore [Universita di Napoli ' ' Federico II' ' , Dipartimento di Fisica ' ' E. Pancini' ' , Naples (Italy); Gran Sasso Science Institute, L' Aquila (Italy); Compl. Univ. di Monte S. Angelo, Naples (Italy); INFN, Napoli (Italy); Faizal, Mir [University of British Columbia - Okanagan, Irving K. Barber School of Arts and Sciences, Kelowna, BC (Canada); University of Lethbridge, Department of Physics and Astronomy, Lethbridge, AB (Canada); Nunes, Rafael C. [Universidade Federal de Juiz de Fora, Departamento de Fisica, Juiz de Fora, MG (Brazil)

    2017-09-15

    Even though it is not possible to differentiate general relativity from teleparallel gravity using classical experiments, it could be possible to discriminate between them by quantum gravitational effects. These effects have motivated the introduction of nonlocal deformations of general relativity, and similar effects are also expected to occur in teleparallel gravity. Here, we study nonlocal deformations of teleparallel gravity along with its cosmological solutions. We observe that nonlocal teleparallel gravity (like nonlocal general relativity) is consistent with the present cosmological data obtained by SNe Ia + BAO + CC + H{sub 0} observations. Along this track, future experiments probing nonlocal effects could be used to test whether general relativity or teleparallel gravity gives the most consistent picture of gravitational interaction. (orig.)

  19. Cochlear Implants

    Science.gov (United States)

    ... For young children who are deaf or severely hard-of-hearing, using a cochlear implant while they are young exposes them to sounds during an optimal period to develop speech and language skills. Research has shown that when these children receive ...

  20. Scattering of massless lumps and non-local charges in the two-dimensional classical non-linear sigma-model

    International Nuclear Information System (INIS)

    Luescher, M.; Pohlmeyer, K.

    1977-09-01

    Finite energy solutions of the field equations of the non-linear sigma-model are shown to decay asymptotically into massless lumps. By means of a linear eigenvalue problem connected with the field equations we then find an infinite set of dynamical conserved charges. They, however, do not provide sufficient information to decode the complicated scattering of lumps. (orig.) [de

  1. Basic considerations on surface optical nonlinearities

    International Nuclear Information System (INIS)

    Guyot-Sionnest, P.; Chen, W.; Shen, Y.R.

    1986-01-01

    The origins of the surface nonlinearity in surface second harmonic generation are discussed. It is shown that this second-order nonlinear optical process is characterized by a surface nonlinear susceptibility tensor containing both local and nonlocal contributions

  2. Nonlocal hidden variables and nonlocal gauge theories

    International Nuclear Information System (INIS)

    Boiteux, M.

    1984-01-01

    A possible unification of classical fundamental interactions together with quantum interactions is proposed, based on an extension of the concept of local gauge invariance to a nonlocal gauge invariance. As an example this new concept is developed for the particular case of the electromagnetic field. (Auth.)

  3. Theory of nonlocal soliton interaction in nematic liquid crystals

    DEFF Research Database (Denmark)

    Rasmussen, Per Dalgaard; Bang, Ole; Krolikowski, Wieslaw

    2005-01-01

    We investigate interactions between spatial nonlocal bright solitons in nematic liquid crystals using an analytical “effective particle” approach as well as direct numerical simulations. The model predicts attraction of out-of-phase solitons and the existence of their stable bound state....... This nontrivial property is solely due to the nonlocal nature of the nonlinear response of the liquid crystals. We further predict and verify numerically the critical outwards angle and degree of nonlocality which determine the transition between attraction and repulsion of out-of-phase solitons....

  4. Localized solutions for a nonlocal discrete NLS equation

    Energy Technology Data Exchange (ETDEWEB)

    Ben, Roberto I. [Instituto de Desarrollo Humano, Universidad Nacional de General Sarmiento, J.M. Gutiérrez 1150, 1613 Los Polvorines (Argentina); Cisneros Ake, Luís [Department of Mathematics, ESFM, Instituto Politécnico Nacional, Unidad Profesional Adolfo López Mateos Edificio 9, 07738 México D.F. (Mexico); Minzoni, A.A. [Depto. Matemáticas y Mecánica, I.I.M.A.S.-U.N.A.M., Apdo. Postal 20-726, 01000 México D.F. (Mexico); Panayotaros, Panayotis, E-mail: panos@mym.iimas.unam.mx [Depto. Matemáticas y Mecánica, I.I.M.A.S.-U.N.A.M., Apdo. Postal 20-726, 01000 México D.F. (Mexico)

    2015-09-04

    We study spatially localized time-periodic solutions of breather type for a cubic discrete NLS equation with a nonlocal nonlinearity that models light propagation in a liquid crystal waveguide array. We show the existence of breather solutions in the limit where both linear and nonlinear intersite couplings vanish, and in the limit where the linear coupling vanishes with arbitrary nonlinear intersite coupling. Breathers of this nonlocal regime exhibit some interesting features that depart from what is seen in the NLS breathers with power nonlinearity. One property we see theoretically is the presence of higher amplitude at interfaces between sites with zero and nonzero amplitude in the vanishing linear coupling limit. A numerical study also suggests the presence of internal modes of orbitally stable localized modes. - Highlights: • Show existence of spatially localized solutions in nonlocal discrete NLS model. • Study spatial properties of localized solutions for arbitrary nonlinear nonlocal coupling. • Present numerical evidence that nonlocality leads to internal modes around stable breathers. • Present theoretical and numerical evidence for amplitude maxima at interfaces.

  5. Nonlocal General Relativity

    Directory of Open Access Journals (Sweden)

    Bahram Mashhoon

    2014-12-01

    Full Text Available A brief account of the present status of the recent nonlocal generalization of Einstein’s theory of gravitation is presented. The main physical assumptions that underlie this theory are described. We clarify the physical meaning and significance of Weitzenböck’s torsion and emphasize its intimate relationship with the gravitational field, characterized by the Riemannian curvature of spacetime. In this theory, nonlocality can simulate dark matter; in fact, in the Newtonian regime, we recover the phenomenological Tohline–Kuhn approach to modified gravity. To account for the observational data regarding dark matter,  nonlocality is associated with a characteristic length scale of order 1 kpc. The confrontation of nonlocal gravity with observation is briefly discussed.

  6. Nonlocal continuum field theories

    CERN Document Server

    2002-01-01

    Nonlocal continuum field theories are concerned with material bodies whose behavior at any interior point depends on the state of all other points in the body -- rather than only on an effective field resulting from these points -- in addition to its own state and the state of some calculable external field. Nonlocal field theory extends classical field theory by describing the responses of points within the medium by functionals rather than functions (the "constitutive relations" of classical field theory). Such considerations are already well known in solid-state physics, where the nonlocal interactions between the atoms are prevalent in determining the properties of the material. The tools developed for crystalline materials, however, do not lend themselves to analyzing amorphous materials, or materials in which imperfections are a major part of the structure. Nonlocal continuum theories, by contrast, can describe these materials faithfully at scales down to the lattice parameter. This book presents a unif...

  7. Controllable nonlocal behaviour by cascaded second-harmonic generation of fs pulses

    DEFF Research Database (Denmark)

    Bache, Morten; Bang, Ole; Krolikowski, Wieslaw

    2008-01-01

    Second-harmonic generation (SHG) of ultra-short pulses can act as a prototypical nonlocal nonlinear model, since the strength and nature of the temporal nonlocality can be controlled through the phase-mismatch parameter. The presence of a group-velocity mismatch namely implies that when the phase...... mismatch is small the nonlocal response function becomes oscillatory, while for large phase mismatch it becomes localized. In the transition between the two regimes the strength of the nonlocality diverges, and the system goes from a weakly nonlocal to a strongly nonlocal state. When simulating soliton...... compression to few-cycle pulses in the cascaded quadratic soliton compressor, the spectral content of the full coupled SHG model is predicted by the nonlocal model even when few-cycle pulses are interacting....

  8. Cochlear Implant

    Directory of Open Access Journals (Sweden)

    Mehrnaz Karimi

    1993-03-01

    Full Text Available People with profound hearing loss are not able to use some kinds of conventional amplifiers due to the nature of their loss. In these people, hearing sense is stimulated only when the auditory nerve is activated via electrical stimulation. This stimulation is possible through cochlear implant. In fact, for the deaf people who have good mental health and can not use surgical and medical treatment and also can not benefit from air and bone conduction hearing aids, this device is used if they have normal central auditory system. The basic parts of the device included: Microphone, speech processor, transmitter, stimulator and receiver, and electrode array.

  9. Cochlear Implant

    Directory of Open Access Journals (Sweden)

    Mehrnaz Karimi

    1992-04-01

    Full Text Available People with profound hearing loss are not able to use some kinds of conventional amplifiers due to the nature of their loss . In these people, hearing sense is stimulated only when the auditory nerve is activated via electrical stimulation. This stimulation is possible through cochlear implant. In fact, for the deaf people who have good mental health and can not use surgical and medical treatment and also can not benefit from air and bone conduction hearing aids, this device is used if they have normal central auditory system. The basic parts of the device included: Microphone, speech processor, transmitter, stimulator and receiver, and electrode array.

  10. Quantum Nonlocality and Beyond: Limits from Nonlocal Computation

    Science.gov (United States)

    Linden, Noah; Popescu, Sandu; Short, Anthony J.; Winter, Andreas

    2007-11-01

    We address the problem of “nonlocal computation,” in which separated parties must compute a function without any individual learning anything about the inputs. Surprisingly, entanglement provides no benefit over local classical strategies for such tasks, yet stronger nonlocal correlations allow perfect success. This provides intriguing insights into the limits of quantum information processing, the nature of quantum nonlocality, and the differences between quantum and stronger-than-quantum nonlocal correlations.

  11. Multi-atlas labeling with population-specific template and non-local patch-based label fusion

    DEFF Research Database (Denmark)

    Fonov, Vladimir; Coupé, Pierrick; Eskildsen, Simon Fristed

    We propose a new method combining a population-specific nonlinear template atlas approach with non-local patch-based structure segmentation for whole brain segmentation into individual structures. This way, we benefit from the efficient intensity-driven segmentation of the non-local means framework...... and from the global shape constraints imposed by the nonlinear template matching....

  12. Nonlocal diffusion and applications

    CERN Document Server

    Bucur, Claudia

    2016-01-01

    Working in the fractional Laplace framework, this book provides models and theorems related to nonlocal diffusion phenomena. In addition to a simple probabilistic interpretation, some applications to water waves, crystal dislocations, nonlocal phase transitions, nonlocal minimal surfaces and Schrödinger equations are given. Furthermore, an example of an s-harmonic function, its harmonic extension and some insight into a fractional version of a classical conjecture due to De Giorgi are presented. Although the aim is primarily to gather some introductory material concerning applications of the fractional Laplacian, some of the proofs and results are new. The work is entirely self-contained, and readers who wish to pursue related subjects of interest are invited to consult the rich bibliography for guidance.

  13. Nonlocality is a nonsequitur

    NARCIS (Netherlands)

    Atkinson, David

    2001-01-01

    Nonlocality in quantum mechanics does not follow from nonseparability, nor does classical stochastic independence imply physical independence. In this paper an explicit proof of a Bell inequality is recalled, and an analysis of the Aspect experiment in terms of noncontextual, but indefinite weights,

  14. Single photon and nonlocality

    Indian Academy of Sciences (India)

    In a paper by Home and Agarwal [1], it is claimed that quantum nonlocality can be revealed in a simple interferometry experiment using only single particles. A critical analysis of the concept of hidden variable used by the authors of [1] shows that the reasoning is not correct.

  15. Nonlocal transport in hot plasma. Part I

    International Nuclear Information System (INIS)

    Brantov, A. V.; Bychenkov, V. Yu.

    2013-01-01

    The problem of describing charged particle transport in hot plasma under the conditions in which the ratio of the electron mean free path to the gradient length is not too small is one of the key problems of plasma physics. However, up to now, there was a deficit of the systematic interpretation of the current state of this problem, which, in most studies, is formulated as the problem of nonlocal transport. In this review, we fill this gap by presenting a self-consistent linear theory of nonlocal transport for small plasma perturbations and an arbitrary collisionality from the classical highly collisional hydrodynamic regime to the collisionless regime. We describe a number of nonlinear transport models and demonstrate the application of the nonclassical transport theory to the solution of some problems of plasma physics, first of all for plasmas produced by nanosecond laser pulses with intensities of 10 13 –10 16 W/cm 2

  16. Individual cochlear delays measured with tone-burst-evoked otoacoustic emissions

    DEFF Research Database (Denmark)

    Pigasse, Gilles; Harte, James; Dau, Torsten

    Methods to estimate cochlear delay in humans have been traditionally based on either phase-derived group delays from otoacoustic emissions (OAEs), or auditory brainstem responses (ABR). These methods demonstrate large variability in cochlear delay estimates, and are derived from across subject...... averages. This work aims to assess the individual variability in cochlear delay. Tone-burst evoked otoacoustic emissions (TBOAEs) are used in this study to estimate cochlear delay. The OAE is analysed by separating the non-linear components of cochlear origin, and the linear reflection in the time domain...

  17. Effect of nonlocal dispersion on self-interacting excitations

    DEFF Research Database (Denmark)

    Christiansen, Peter Leth; Rasmussen, Kim; Gaididei, Yu.B.

    1996-01-01

    The dynamics of self-interacting quasiparticles in 1Dsystems with long-range dispersive interactions isexpressed in terms of a nonlocal nonlinear Schrödingerequation. Two branches of stationary solutions are found.The new branch which contains a cusp soliton is shown to beunstable and blowup...... is observed. Moving solitons radiatewith a wavelength proportional to the velocity....

  18. Nonlocal gauge theories

    International Nuclear Information System (INIS)

    Partovi, M.H.

    1982-01-01

    From a generalization of the covariant derivative, nonlocal gauge theories are developed. These theories enjoy local gauge invariance and associated Ward identities, a corresponding locally conserved current, and a locally conserved energy-momentum tensor, with the Ward identities implying the masslessness of the gauge field as in local theories. Their ultraviolet behavior allows the presence as well as the absence of the Adler-Bell-Jackiw anomaly, the latter in analogy with lattice theories

  19. Analytical theory of dark nonlocal solitons

    DEFF Research Database (Denmark)

    Kong, Qian; Wang, Qi; Bang, Ole

    2010-01-01

    We investigate properties of dark solitons in nonlocal materials with an arbitrary degree of nonlocality. We employ the variational technique and describe dark solitons, for the first time to our knowledge, in the whole range of degree of nonlocality....

  20. Pattern transitions and complexity for a nonlocal logistic map

    Science.gov (United States)

    Barbosa, Fernando V.; Penna, André A. L.; Ferreira, Rogelma M. S.; Novais, Keila L. V.; da Cunha, Jefferson A. R.; Oliveira, Fernando A.

    2017-05-01

    We examine the pattern solutions in a generalized nonlocal logistic map that includes spatial kernels in both growth and competition terms. We show that this map includes as a particular case the nonlocal Fisher-Kolmogorov equation, and we demonstrate the existence of three kinds of stationary nonlinear solutions: one uniform, one cosine type that we refer to as wavelike solution, and another in the form of Gaussian. We also obtain analytical expressions that describe the nonlinear pattern behavior in the system, and we establish the stability criterion. We define thermodynamics quantities such as entropy and the order parameter. Based on this, the pattern-no-pattern and pattern-pattern transitions are properly analyzed. We show that these pattern solutions may be related to the recently observed peak adding phenomenon in nonlinear optics.

  1. Cochlear outer hair cells in a dominant-negative connexin26 mutant mouse preserve non-linear capacitance in spite of impaired distortion product otoacoustic emission.

    Science.gov (United States)

    Minekawa, A; Abe, T; Inoshita, A; Iizuka, T; Kakehata, S; Narui, Y; Koike, T; Kamiya, K; Okamura, H-O; Shinkawa, H; Ikeda, K

    2009-12-15

    Mutations in the connexin26 gene (GJB2) are the most common genetic cause of congenital bilateral non-syndromic sensorineural hearing loss. Transgenic mice were established carrying human Cx26 with the R75W mutation that was identified in a deaf family with autosomal dominant negative inheritance [Kudo T et al. (2003) Hum Mol Genet 12:995-1004]. A dominant-negative Gjb2 R75W transgenic mouse model shows incomplete development of the cochlear supporting cells, resulting in profound deafness from birth [Inoshita A et al. (2008) Neuroscience 156:1039-1047]. The Cx26 defect in the Gjb2 R75W transgenic mouse is restricted to the supporting cells; it is unclear why the auditory response is severely disturbed in spite of the presence of outer hair cells (OHCs). The present study was designed to evaluate developmental changes in the in vivo and in vitro function of the OHC, and the fine structure of the OHC and adjacent supporting cells in the R75W transgenic mouse. No detectable distortion product otoacoustic emissions were observed at any frequencies in R75W transgenic mice throughout development. A characteristic phenotype observed in these mice was the absence of the tunnel of Corti, Nuel's space, and spaces surrounding the OHC; the OHC were compressed and squeezed by the surrounding supporting cells. On the other hand, the OHC developed normally. Structural features of the lateral wall, such as the membrane-bound subsurface cisterna beneath the plasma membrane, were intact. Prestin, the voltage-dependent motor protein, was observed by immunohistochemistry in the OHC basolateral membranes of both transgenic and non-transgenic mice. No significant differences in electromotility of isolated OHCs during development was observed between transgenic and control mice. The present study indicates that normal development of the supporting cells is indispensable for proper cellular function of the OHC.

  2. Quadratic solitons as nonlocal solitons

    DEFF Research Database (Denmark)

    Nikolov, Nikola Ivanov; Neshev, D.; Bang, Ole

    2003-01-01

    We show that quadratic solitons are equivalent to solitons of a nonlocal Kerr medium. This provides new physical insight into the properties of quadratic solitons, often believed to be equivalent to solitons of an effective saturable Kerr medium. The nonlocal analogy also allows for analytical...... solutions and the prediction of bound states of quadratic solitons....

  3. Nonlocal Sediment Transport on Steep Lateral Moraines, Eastern Sierra Nevada, California, USA

    Science.gov (United States)

    Doane, Tyler H.; Furbish, David Jon; Roering, Joshua J.; Schumer, Rina; Morgan, Daniel J.

    2018-01-01

    Recent work has highlighted the significance of long-distance particle motions in hillslope sediment transport. Such motions imply that the flux at a given hillslope position is appropriately described as a weighted function of surrounding conditions that influence motions reaching the given position. Although the idea of nonlocal sediment transport is well grounded in theory, limited field evidence has been provided. We test local and nonlocal formulations of the flux and compare their ability to reproduce land surface profiles of steep moraines in California. We show that nonlocal and nonlinear models better reproduce evolved land surface profiles, notably the amount of lowering and concavity near the moraine crest and the lengthening and straightening of the depositional apron. The analysis provides the first estimates of key parameters that set sediment entrainment rates and travel distances in nonlocal formulations and highlights the importance of correctly specifying the entrainment rate when modeling land surface evolution. Moraine evolution associated with nonlocal and nonlinear transport formulations, when described in terms of the evolution of the Fourier transform of the moraine surface, displays a distinct behavior involving growth of certain wave numbers, in contrast to the decay of all wave numbers associated with linear transport. Nonlinear and nonlocal formulations share key mathematical elements yielding a nonlinear relation between the flux and the land surface slope.

  4. Nonlocal optical response in metallic nanostructures

    DEFF Research Database (Denmark)

    Raza, Søren; Bozhevolnyi, Sergey I.; Wubs, Martijn

    2015-01-01

    This review provides a broad overview of the studies and effects of nonlocal response in metallic nanostructures. In particular, we thoroughly present the nonlocal hydrodynamic model and the recently introduced generalized nonlocal optical response (GNOR) model. The influence of nonlocal response...

  5. Hyper- and hybrid nonlocality

    Science.gov (United States)

    Li, Yanna; Gessner, Manuel; Li, Weidong; Smerzi, Augusto

    2018-02-01

    The controlled generation and identification of quantum correlations, usually encoded in either qubits or continuous degrees of freedom, builds the foundation of quantum information science. Recently, more sophisticated approaches, involving a combination of two distinct degrees of freedom, have been proposed to improve on the traditional strategies. Hyperentanglement describes simultaneous entanglement in more than one distinct degree of freedom, whereas hybrid entanglement refers to entanglement shared between a discrete and a continuous degree of freedom. In this work we propose a scheme that allows us to combine the two approaches, and to extend them to the strongest form of quantum correlations. Specifically, we show how two identical, initially separated particles can be manipulated to produce Bell nonlocality among their spins, among their momenta, as well as across their spins and momenta. We discuss possible experimental realizations with atomic and photonic systems.

  6. Turbulence transport with nonlocal interactions

    Energy Technology Data Exchange (ETDEWEB)

    Linn, R.R.; Clark, T.T.; Harlow, F.H.; Turner, L.

    1998-03-01

    This preliminary report describes a variety of issues in turbulence transport analysis with particular emphasis on closure procedures that are nonlocal in wave-number and/or physical space. Anomalous behavior of the transport equations for large scale parts of the turbulence spectrum are resolved by including the physical space nonlocal interactions. Direct and reverse cascade processes in wave-number space are given a much richer potential for realistic description by the nonlocal formulations. The discussion also describes issues, many still not resolved, regarding new classes of self-similar form functions.

  7. Bounds for nonlocality distillation protocols

    International Nuclear Information System (INIS)

    Forster, Manuel

    2011-01-01

    Nonlocality can be quantified by the violation of a Bell inequality. Since this violation may be amplified by local operations, an alternative measure has been proposed--distillable nonlocality. The alternative measure is difficult to calculate exactly due to the double exponential growth of the parameter space. In this paper, we give a way to bound the distillable nonlocality of a resource by the solutions to a related optimization problem. Our upper bounds are exponentially easier to compute than the exact value and are shown to be meaningful in general and tight in some cases.

  8. A third-order nonlocal problem with nonlocal conditions

    Directory of Open Access Journals (Sweden)

    Lazhar Bougoffa

    2004-01-01

    Full Text Available We study an equation with dominated lower-order terms and nonlocal conditions. Using the Riesz representation theorem and the Schauder fixed-point theorem, we prove the existence and uniqueness of a generalized solution.

  9. Flaw-tolerance of nonlocal discrete systems and interpretation according to network theory

    Directory of Open Access Journals (Sweden)

    A. Infuso

    2014-07-01

    Full Text Available Discrete systems are modeled as a network of nodes (particles, molecules, or atoms linked by nonlinear springs to simulate the action of van der Waals forces. Such systems are nonlocal if links connecting non-adjacent nodes are introduced. For their topological characterization, a nonlocality index (NLI inspired by network theory is proposed. The mechanical response of 1D and 2D nonlocal discrete systems is predicted according to finite element (FE simulations based on a nonlinear spring element for large displacements implemented in the FE programme FEAP. Uniaxial force-displacement responses of intact and defective systems (with links or nodes removed are numerically simulated. Strain localization phenomena, size-scale effects and the ability to tolerate defects are investigated by varying the degree of nonlocality.

  10. A comparative study of seven human cochlear filter models.

    Science.gov (United States)

    Saremi, Amin; Beutelmann, Rainer; Dietz, Mathias; Ashida, Go; Kretzberg, Jutta; Verhulst, Sarah

    2016-09-01

    Auditory models have been developed for decades to simulate characteristics of the human auditory system, but it is often unknown how well auditory models compare to each other or perform in tasks they were not primarily designed for. This study systematically analyzes predictions of seven publicly-available cochlear filter models in response to a fixed set of stimuli to assess their capabilities of reproducing key aspects of human cochlear mechanics. The following features were assessed at frequencies of 0.5, 1, 2, 4, and 8 kHz: cochlear excitation patterns, nonlinear response growth, frequency selectivity, group delays, signal-in-noise processing, and amplitude modulation representation. For each task, the simulations were compared to available physiological data recorded in guinea pigs and gerbils as well as to human psychoacoustics data. The presented results provide application-oriented users with comprehensive information on the advantages, limitations and computation costs of these seven mainstream cochlear filter models.

  11. Nonlocal heat transfer in nanostructures

    International Nuclear Information System (INIS)

    Kanavin, A.P.; Uryupin, S.A.

    2008-01-01

    Kinetics of electrons in a degenerate conductor heated up by absorption of a high-frequency field localized in a region of about hundred nanometers has been studied. A new law for nonlocal electron thermal flux has been predicted

  12. Solutions of Nonlocal -Laplacian Equations

    Directory of Open Access Journals (Sweden)

    Mustafa Avci

    2013-01-01

    Full Text Available In view of variational approach we discuss a nonlocal problem, that is, a Kirchhoff-type equation involving -Laplace operator. Establishing some suitable conditions, we prove the existence and multiplicity of solutions.

  13. Self-localized states for electron transfer in nonlocal continuum deformable media

    Energy Technology Data Exchange (ETDEWEB)

    Cisneros-Ake, Luis A., E-mail: cisneros@esfm.ipn.mx

    2016-08-19

    We consider the problem of electron transport in a deformable continuum medium subjected to an external harmonic substrate potential. We then consider the quasi-stationary state of the full problem to find a Gross–Pitaevskii type equation with a nonlocal external potential, which is solved by variational and numerical means (considered as the exact solution) to find the parameter conditions for the existence of self-localized solutions. The variational approach predicts a threshold on the on-site or nonlocality parameter where localized solutions cease to exist from the Non-Linear Schrödinger soliton limit. A numerical continuation of stationary state solutions in the corresponding discrete system is used to confirm the prediction of the turning value in the on-site term. We finally study the full stationary state and make use of an approximation, proposed by Briedis et al. [17], for the nonlocal term, corresponding to strong nonlocalities, to find analytic expressions for self-localized states in terms of the series solutions of a nonlinear modified Bessel equation. - Highlights: • Nonlocality overcomes nonlinearity at a threshold value to cease the existence of coherent solutions. • Variational and series expansion solutions predict the formation of coherent structures in nonlocal deformable media. • Full numerical solutions confirm the persistence of localized solutions.

  14. Nonlocal Intracranial Cavity Extraction

    Science.gov (United States)

    Manjón, José V.; Eskildsen, Simon F.; Coupé, Pierrick; Romero, José E.; Collins, D. Louis; Robles, Montserrat

    2014-01-01

    Automatic and accurate methods to estimate normalized regional brain volumes from MRI data are valuable tools which may help to obtain an objective diagnosis and followup of many neurological diseases. To estimate such regional brain volumes, the intracranial cavity volume (ICV) is often used for normalization. However, the high variability of brain shape and size due to normal intersubject variability, normal changes occurring over the lifespan, and abnormal changes due to disease makes the ICV estimation problem challenging. In this paper, we present a new approach to perform ICV extraction based on the use of a library of prelabeled brain images to capture the large variability of brain shapes. To this end, an improved nonlocal label fusion scheme based on BEaST technique is proposed to increase the accuracy of the ICV estimation. The proposed method is compared with recent state-of-the-art methods and the results demonstrate an improved performance both in terms of accuracy and reproducibility while maintaining a reduced computational burden. PMID:25328511

  15. Nonlocal Intracranial Cavity Extraction

    Directory of Open Access Journals (Sweden)

    José V. Manjón

    2014-01-01

    Full Text Available Automatic and accurate methods to estimate normalized regional brain volumes from MRI data are valuable tools which may help to obtain an objective diagnosis and followup of many neurological diseases. To estimate such regional brain volumes, the intracranial cavity volume (ICV is often used for normalization. However, the high variability of brain shape and size due to normal intersubject variability, normal changes occurring over the lifespan, and abnormal changes due to disease makes the ICV estimation problem challenging. In this paper, we present a new approach to perform ICV extraction based on the use of a library of prelabeled brain images to capture the large variability of brain shapes. To this end, an improved nonlocal label fusion scheme based on BEaST technique is proposed to increase the accuracy of the ICV estimation. The proposed method is compared with recent state-of-the-art methods and the results demonstrate an improved performance both in terms of accuracy and reproducibility while maintaining a reduced computational burden.

  16. Symmetries of nonlinear ordinary differential equations: The ...

    Indian Academy of Sciences (India)

    2015-10-21

    Oct 21, 2015 ... Lie point symmetries; -symmetries; Noether symmetries; contact symmetries; adjoint symmetries; nonlocal symmetries; hidden symmetries; ... 620 024, India; Centre for Nonlinear Science and Engineering, School of Electrical and Electronics Engineering, SASTRA University, Thanjavur 613 401, India ...

  17. Ermakov's Superintegrable Toy and Nonlocal Symmetries

    Directory of Open Access Journals (Sweden)

    P.G.L. Leach

    2005-11-01

    Full Text Available We investigate the symmetry properties of a pair of Ermakov equations. The system is superintegrable and yet possesses only three Lie point symmetries with the algebra sl(2, R. The number of point symmetries is insufficient and the algebra unsuitable for the complete specification of the system. We use the method of reduction of order to reduce the nonlinear fourth-order system to a third-order system comprising a linear second-order equation and a conservation law. We obtain the representation of the complete symmetry group from this system. Four of the required symmetries are nonlocal and the algebra is the direct sum of a one-dimensional Abelian algebra with the semidirect sum of a two-dimensional solvable algebra with a two-dimensional Abelian algebra. The problem illustrates the difficulties which can arise in very elementary systems. Our treatment demonstrates the existence of possible routes to overcome these problems in a systematic fashion.

  18. Ermakov's Superintegrable Toy and Nonlocal Symmetries

    Science.gov (United States)

    Leach, P. G. L.; Karasu Kalkanli, A.; Nucci, M. C.; Andriopoulos, K.

    2005-11-01

    We investigate the symmetry properties of a pair of Ermakov equations. The system is superintegrable and yet possesses only three Lie point symmetries with the algebra sl(2, R). The number of point symmetries is insufficient and the algebra unsuitable for the complete specification of the system. We use the method of reduction of order to reduce the nonlinear fourth-order system to a third-order system comprising a linear second-order equation and a conservation law. We obtain the representation of the complete symmetry group from this system. Four of the required symmetries are nonlocal and the algebra is the direct sum of a one-dimensional Abelian algebra with the semidirect sum of a two-dimensional solvable algebra with a two-dimensional Abelian algebra. The problem illustrates the difficulties which can arise in very elementary systems. Our treatment demonstrates the existence of possible routes to overcome these problems in a systematic fashion.

  19. COCHLEAR IMPLANTATION: MY EXPERIENCE

    OpenAIRE

    Shankar

    2015-01-01

    Cochlear implant is a small, surgically implanted complex electronic device that can help to provide a sense of sound to a person with severe to profound sensorineural hearing loss. This type of hearing loss, typically involves damage to hair cells in the cochlea, as a result sound cannot reach the auditory nerve which usually receives information from hair cells. A cochlear implant skips the damaged hair cells and to stimulate the auditory nerve directly. An implant does not rest...

  20. Nonlocal symmetries and nonlocal conservation laws of Maxwell's equations

    International Nuclear Information System (INIS)

    Anco, S.C.; Bluman, G.

    1997-01-01

    Nonlocal symmetries are obtained for Maxwell's equations in three space-time dimensions through the use of two potential systems involving scalar and vector potentials for the electromagnetic field. Corresponding nonlocal conservation laws are derived from these symmetries. The conservation laws yield nine functionally independent constants of motion which cannot be expressed in terms of the constants of motion arising from local conservation laws for space-time symmetries. These nine constants of motion represent additional conserved quantities for the electromagnetic field in three space endash time dimensions. copyright 1997 American Institute of Physics

  1. Nonlocal higher order evolution equations

    KAUST Repository

    Rossi, Julio D.

    2010-06-01

    In this article, we study the asymptotic behaviour of solutions to the nonlocal operator ut(x, t)1/4(-1)n-1 (J*Id -1)n (u(x, t)), x ∈ ℝN, which is the nonlocal analogous to the higher order local evolution equation vt(-1)n-1(Δ)nv. We prove that the solutions of the nonlocal problem converge to the solution of the higher order problem with the right-hand side given by powers of the Laplacian when the kernel J is rescaled in an appropriate way. Moreover, we prove that solutions to both equations have the same asymptotic decay rate as t goes to infinity. © 2010 Taylor & Francis.

  2. Nonlocal Response in Plasmonic Nanostructures

    DEFF Research Database (Denmark)

    Wubs, Martijn; Mortensen, N. Asger

    2016-01-01

    After a brief overview of nanoplasmonics experiments that defy explanation with classical electrodynamics, we introduce nonlocal response as a main reason for non-classical effects. This concept is first introduced phenomenologically, and afterwards based on the semi-classical hydrodynamic Drude...... model (HDM) that indeed exhibits nonlocal response. In particular, we discuss recent generalizations and extensions of the HDM, to include both convection and diffusion dynamics of the induced charges. This generalized nonlocal optical response (GNOR) model allows for the first time unified semi-classical...... explanations of known experimental phenomena for both monomers and dimers that previously seemed to require microscopic theory. Finally, we turn to Landau damping and discuss the microscopic origin of the size-dependent damping captured by the classical diffusion mechanism in the GNOR model....

  3. Closed sets of nonlocal correlations

    International Nuclear Information System (INIS)

    Allcock, Jonathan; Linden, Noah; Brunner, Nicolas; Popescu, Sandu; Skrzypczyk, Paul; Vertesi, Tamas

    2009-01-01

    We present a fundamental concept - closed sets of correlations - for studying nonlocal correlations. We argue that sets of correlations corresponding to information-theoretic principles, or more generally to consistent physical theories, must be closed under a natural set of operations. Hence, studying the closure of sets of correlations gives insight into which information-theoretic principles are genuinely different, and which are ultimately equivalent. This concept also has implications for understanding why quantum nonlocality is limited, and for finding constraints on physical theories beyond quantum mechanics.

  4. [Biomaterials in cochlear implants].

    Science.gov (United States)

    Stöver, T; Lenarz, T

    2009-05-01

    Cochlear implants (CI) represent the "gold standard" for the treatment of congenitally deaf children and postlingually deafened adults. Thus, cochlear implantation is a success story of new bionic prosthesis development. Owing to routine application of cochlear implants in adults but also in very young children (below the age of one), high demands are placed on the implants. This is especially true for biocompatibility aspects of surface materials of implant parts which are in contact with the human body. In addition, there are various mechanical requirements which certain components of the implants must fulfil, such as flexibility of the electrode array and mechanical resistance of the implant housing. Due to the close contact of the implant to the middle ear mucosa and because the electrode array is positioned in the perilymphatic space via cochleostomy, there is a potential risk of bacterial transferral along the electrode array into the cochlea. Various requirements that have to be fulfilled by cochlear implants, such as biocompatibility, electrode micromechanics, and although a very high level of technical standards has been carried out there is still demand for the improvement of implants as well as of the materials used for manufacturing, ultimately leading to increased implant performance. General considerations of material aspects related to cochlear implants as well as potential future perspectives of implant development will be discussed.

  5. Learning Non-Local Dependencies

    Science.gov (United States)

    Kuhn, Gustav; Dienes, Zoltan

    2008-01-01

    This paper addresses the nature of the temporary storage buffer used in implicit or statistical learning. Kuhn and Dienes [Kuhn, G., & Dienes, Z. (2005). Implicit learning of nonlocal musical rules: implicitly learning more than chunks. "Journal of Experimental Psychology-Learning Memory and Cognition," 31(6) 1417-1432] showed that people could…

  6. Nonlocal quasilinear damped differential inclusions

    Directory of Open Access Journals (Sweden)

    Mouffak Benchohra

    2002-01-01

    Full Text Available In this paper we investigate the existence of mild solutions to second order initial value problems for a class of damped differential inclusions with nonlocal conditions. By using suitable fixed point theorems, we study the case when the multivalued map has convex and nonconvex values.

  7. Quantum nonlocality does not exist.

    Science.gov (United States)

    Tipler, Frank J

    2014-08-05

    Quantum nonlocality is shown to be an artifact of the Copenhagen interpretation, in which each observed quantity has exactly one value at any instant. In reality, all physical systems obey quantum mechanics, which obeys no such rule. Locality is restored if observed and observer are both assumed to obey quantum mechanics, as in the many-worlds interpretation (MWI). Using the MWI, I show that the quantum side of Bell's inequality, generally believed nonlocal, is really due to a series of three measurements (not two as in the standard, oversimplified analysis), all three of which have only local effects. Thus, experiments confirming "nonlocality" are actually confirming the MWI. The mistaken interpretation of nonlocality experiments depends crucially on a question-begging version of the Born interpretation, which makes sense only in "collapse" versions of quantum theory, about the meaning of the modulus of the wave function, so I use the interpretation based on the MWI, namely that the wave function is a world density amplitude, not a probability amplitude. This view allows the Born interpretation to be derived directly from the Schrödinger equation, by applying the Schrödinger equation to both the observed and the observer.

  8. Nonlocal interactions and Bell's inequality

    International Nuclear Information System (INIS)

    Garuccio, A.; Selleri, F.

    1976-01-01

    It is shown that natural extensions of the local hidden variable theories to include nonlocal effects still lead to a full validity of Bell's inequality. It is conjectured that the essential point expressed by this inequality is not locality, but the wave-particle dualism

  9. Nonlocal multi-scale traffic flow models: analysis beyond vector spaces

    Directory of Open Access Journals (Sweden)

    Peter E. Kloeden

    2016-08-01

    Full Text Available Abstract Realistic models of traffic flow are nonlinear and involve nonlocal effects in balance laws. Flow characteristics of different types of vehicles, such as cars and trucks, need to be described differently. Two alternatives are used here, $$L^p$$ L p -valued Lebesgue measurable density functions and signed Radon measures. The resulting solution spaces are metric spaces that do not have a linear structure, so the usual convenient methods of functional analysis are no longer applicable. Instead ideas from mutational analysis will be used, in particular the method of Euler compactness will be applied to establish the well-posedness of the nonlocal balance laws. This involves the concatenation of solutions of piecewise linear systems on successive time subintervals obtained by freezing the nonlinear nonlocal coefficients to their values at the start of each subinterval. Various compactness criteria lead to a convergent subsequence. Careful estimates of the linear systems are needed to implement this program.

  10. Phase of shear vibrations within cochlear partition leads to activation of the cochlear amplifier.

    Directory of Open Access Journals (Sweden)

    Jessica S Lamb

    Full Text Available Since Georg von Bekesy laid out the place theory of the hearing, researchers have been working to understand the remarkable properties of mammalian hearing. Because access to the cochlea is restricted in live animals, and important aspects of hearing are destroyed in dead ones, models play a key role in interpreting local measurements. Wentzel-Kramers-Brillouin (WKB models are attractive because they are analytically tractable, appropriate to the oblong geometry of the cochlea, and can predict wave behavior over a large span of the cochlea. Interest in the role the tectorial membrane (TM plays in cochlear tuning led us to develop models that directly interface the TM with the cochlear fluid. In this work we add an angled shear between the TM and reticular lamina (RL, which serves as an input to a nonlinear active force. This feature plus a novel combination of previous work gives us a model with TM-fluid interaction, TM-RL shear, a nonlinear active force and a second wave mode. The behavior we get leads to the conclusion the phase between the shear and basilar membrane (BM vibration is critical for amplification. We show there is a transition in this phase that occurs at a frequency below the cutoff, which is strongly influenced by TM stiffness. We describe this mechanism of sharpened BM velocity profile, which demonstrates the importance of the TM in overall cochlear tuning and offers an explanation for the response characteristics of the Tectb mutant mouse.

  11. Benefits and Risks of Cochlear Implants

    Science.gov (United States)

    ... music. Some enjoy the sound of certain instruments (piano or guitar, for example) and certain voices. Others ... in Cochlear Implants What is a Cochlear Implant? Benefits and Risks of Cochlear Implants Frequently Asked Questions ...

  12. Local shell-to-shell energy transfer via nonlocal interactions in fluid ...

    Indian Academy of Sciences (India)

    In this paper we analytically compute the strength of nonlinear interactions in a triad, and the energy exchanges between wave-number shells in incompressible fluid turbulence. The computation has been done using first-order perturbative field theory. In three dimensions, magnitude of triad interactions is large for nonlocal ...

  13. Cochlear-Meningitis Vaccination

    Science.gov (United States)

    ... not routinely recommended for those 5 years of age or older, since most older children and adults are already immune to Hib. Available information does not suggest that older children and adults with cochlear implants require the Hib vaccine. However, the Hib vaccine ...

  14. Temporal nonlocality in bistable perception

    Science.gov (United States)

    Atmanspacher, Harald; Filk, Thomas

    2012-12-01

    A novel conceptual framework for theoretical psychology is presented and illustrated for the example of bistable perception. A basic formal feature of this framework is the non-commutativity of operations acting on mental states. A corresponding model for the bistable perception of ambiguous stimuli, the Necker-Zeno model, is sketched and some empirical evidence for it so far is described. It is discussed how a temporal nonlocality of mental states, predicted by the model, can be understood and tested.

  15. Continuous-variable supraquantum nonlocality

    Science.gov (United States)

    Ketterer, Andreas; Laversanne-Finot, Adrien; Aolita, Leandro

    2018-01-01

    Supraquantum nonlocality refers to correlations that are more nonlocal than allowed by quantum theory but still physically conceivable in postquantum theories, in the sense of respecting the basic no-faster-than-light communication principle. While supraquantum correlations are relatively well understood for finite-dimensional systems, little is known in the infinite-dimensional case. Here, we study supraquantum nonlocality for bipartite systems with two measurement settings and infinitely many outcomes per subsystem. We develop a formalism for generic no-signaling black-box measurement devices with continuous outputs in terms of probability measures, instead of probability distributions, which involves a few technical subtleties. We show the existence of a class of supraquantum Gaussian correlations, which violate the Tsirelson bound of an adequate continuous-variable Bell inequality. We then introduce the continuous-variable version of the celebrated Popescu-Rohrlich (PR) boxes, as a limiting case of the above-mentioned Gaussian ones. Finally, we characterize the geometry of the set of continuous-variable no-signaling correlations. Namely, we show that that the convex hull of the continuous-variable PR boxes is dense in the no-signaling set. We also show that these boxes are extreme in the set of no-signaling behaviors and provide evidence suggesting that they are indeed the only extreme points of the no-signaling set. Our results lay the grounds for studying generalized-probability theories in continuous-variable systems.

  16. Nonlocal postbuckling analysis of graphene sheets with initial imperfection based on first order shear deformation theory

    Directory of Open Access Journals (Sweden)

    Ahmad Soleimani

    Full Text Available In this paper, the first order shear deformation theory (FSDT is used to investigate the postbuckling behavior of orthotropic single-layered graphene sheet (SLGS under in-plane loadings. Nonlocal elasticity theory and von-Karman nonlinear model in combination with the isogeometric analysis (IGA have been applied to study the postbuckling characteristics of SLGSs. In contrast to the classical model, the nonlocal continuum model developed in this work considers the size-effects on the postbuckling characteristics of SLGSs. FSDT takes into account effects of shear deformations through-the-thickness of plate. Geometric imperfection which is defined as a very small transverse displacement of the mid-plane is applied on undeformed nanoplate to create initial deviation in graphene sheet from being perfectly flat. Nonlinear governing equations of motion for SLGS are derived from the principle of virtual work and a variational formulation. At the end, the results are presented as the postbuckling equilibrium paths of SLGS. The influence of various parameters such as edge length, nonlocal parameter, compression ratio, boundary conditions and aspect ratio on the postbuckling path is investigated. The results of this work show the high accuracy of nonlocal FSDT-based analysis for postbuckling behavior of graphene sheets. Keywords: Postbuckling analysis, Graphene sheet, Nonlocal elasticity, First order shear deformation theory, Isogeometric analysis, Initial imperfection

  17. Generic features of modulational instability in nonlocal Kerr media

    DEFF Research Database (Denmark)

    Wyller, John; Krolikowski, Wieslaw; Bang, Ole

    2002-01-01

    the nonlocality tends to suppress MI, but can never remove it completely, irrespectively of the shape of the response function. For a defocusing nonlinearity the stability properties depend sensitively on the profile of the response function. For response functions with a positive-definite spectrum......, such as Gaussians and exponentials, plane waves are always stable, whereas response functions with spectra that are not positive definite (such as the rectangular) will lead to MI if sigma exceeds a certain threshold. For the square response function, in both the focusing and defocusing case, we show analytically...

  18. Cochlear implantation in Mondini dysplasia.

    Science.gov (United States)

    Daneshi, Ahmad; Hassanzadeh, Saeid; Abasalipour, Parvaneh; Emamdjomeh, Hessamaddin; Farhadi, Mohammad

    2003-01-01

    The use of cochlear implantation to treat patients with inner ear malformations such as Mondini dysplasia has been increasingly successful. Until now, conventional hearing aids in these patients have not performed well. Consequently, the hearing problem for patients with this condition has been somewhat improved with the use of cochlear implants. Various results of cochlear implantation have been reported in these patients so far. This is a report of 5 patients with Mondini malformation who have undergone cochlear implant surgery. Copyright 2003 S. Karger AG, Basel

  19. Non-Local Effects in Kaonic Atoms

    International Nuclear Information System (INIS)

    Lutz, M.; Florkowski, W.

    2000-01-01

    Optical potentials with non-local (gradient) terms are used to describe the spectra of kaonic atoms. The strength of the non-local terms is determined from a many-body calculation of the kaon self energy in nuclear matter. We find that the non-local terms are quantitatively important and the results depend strongly on the way the gradient terms are arranged. Phenomenologically successful description is obtained for p-wave like optical potentials. It is suggested that the microscopic form of the non-local interaction terms is obtained systematically by means of a semi-classical expansion of the nucleus structure. (author)

  20. Existence of solutions of nonlinear integrodifferential equations of ...

    Indian Academy of Sciences (India)

    Abstract. In this paper we prove the existence of mild and strong solutions of a nonlinear integrodifferential equation of Sobolev type with nonlocal condition. The results are obtained by using semigroup theory and the Schauder fixed point theorem.

  1. Coherent dynamics of singlet fission controlled by nonlocal electron-phonon coupling

    Science.gov (United States)

    Yao, Yao

    2016-03-01

    Based on the Frenkel and charge transfer mixing model of singlet fission (SF), we incorporate both the local and nonlocal phonon baths into the Hamiltonian and adopt the algorithm of the time-dependent density matrix renormalization group to simulate the SF process in tetracene and pentacene. The endergonic SF is found to be facilitated by the robust quantum coherence, which concurrently gives rise to a notable quantum beating effect. Being controlled by the nonlocal electron-phonon coupling, the SF process is accelerated and the triplet yield manifests a nonlinear relationship with the singlet density.

  2. Efter cochlear implant

    DEFF Research Database (Denmark)

    Højen, Anders

    2007-01-01

      Dit barn har netop fået et cochlear implant. Hvad nu? Skal barnet fokusere udelukkende på at lære talt sprog, eller skal det også lære/fortsætte med tegnsprog eller støttetegn? Det er et vanskeligt spørgsmål, og før valget foretages, er det vigtigt at vurdere hvilke konsekvenser valget har, dels...... for den sproglige udvikling isoleret set, og dels for barnets udvikling ud fra en helhedsbetragtning. Dette indlæg fokuserer på, hvilke forventninger man kan have til cochlear implant-brugeres sproglige udvikling med talt sprog alene, hhv. med to sprog (tale og tegn). Disse forventninger er baseret på...

  3. Efter cochlear implant

    DEFF Research Database (Denmark)

    Højen, Anders

    Dit barn har netop fået et cochlear implant. Hvad nu? Skal barnet fokusere udelukkende på at lære talt sprog, eller skal det også lære/fortsætte med tegnsprog eller støttetegn? Det er et vanskeligt spørgsmål, og før valget foretages, er det vigtigt at vurdere hvilke konsekvenser valget har, dels...... for den sproglige udvikling isoleret set, og dels for barnets udvikling ud fra en helhedsbetragtning. Dette indlæg fokuserer på, hvilke forventninger man kan have til cochlear implant-brugeres sproglige udvikling med talt sprog alene, hhv. med to sprog (tale og tegn). Disse forventninger er baseret på...

  4. Cochlear implantation in patients with bilateral cochlear trauma.

    Science.gov (United States)

    Serin, Gediz Murat; Derinsu, Ufuk; Sari, Murat; Gergin, Ozgül; Ciprut, Ayça; Akdaş, Ferda; Batman, Cağlar

    2010-01-01

    Temporal bone fracture, which involves the otic capsule, can lead to complete loss of auditory and vestibular functions, whereas the patients without fractures may experience profound sensorineural hearing loss due to cochlear concussion. Cochlear implant is indicated in profound sensorineural hearing loss due to cochlear trauma but who still have an intact auditory nerve. This is a retrospective review study. We report 5 cases of postlingually deafened patients caused by cochlear trauma, who underwent cochlear implantation. Preoperative and postoperative hearing performance will be presented. These patients are cochlear implanted after the cochlear trauma in our department between 2001 and 2006. All patients performed very well with their implants, obtained open-set speech understanding. They all became good telephone users after implantation. Their performance in speech understanding was comparable to standard postlingual adult patients implanted. Cochlear implantation is an effective aural rehabilitation in profound sensorineural hearing loss caused by temporal bone trauma. Preoperative temporal bone computed tomography, magnetic resonance imaging, and promontorium stimulation testing are necessary to make decision for the surgery and to determine the side to be implanted. Surgery could be challenging and complicated because of anatomical irregularity. Moreover, fibrosis and partial or total ossification within the cochlea must be expected. Copyright 2010. Published by Elsevier Inc.

  5. Eringen's theory of Nonlocal Elasticity (cont…)

    Indian Academy of Sciences (India)

    Eringen's theory of Nonlocal Elasticity (cont…) Integro-Partial differential equations of the above linear nonlocal elasticity have been proposed leading to singular partial differential equations of a special class of ... The scale coefficient in the modeling will lead to small-scale effect on the response of structures in nano-size.

  6. Virial Theorem in Nonlocal Newtonian Gravity

    Directory of Open Access Journals (Sweden)

    Bahram Mashhoon

    2016-05-01

    Full Text Available Nonlocal gravity is the recent classical nonlocal generalization of Einstein’s theory of gravitation in which the past history of the gravitational field is taken into account. In this theory, nonlocality appears to simulate dark matter. The virial theorem for the Newtonian regime of nonlocal gravity theory is derived and its consequences for “isolated” astronomical systems in virial equilibrium at the present epoch are investigated. In particular, for a sufficiently isolated nearby galaxy in virial equilibrium, the galaxy’s baryonic diameter D 0 —namely, the diameter of the smallest sphere that completely surrounds the baryonic system at the present time—is predicted to be larger than the effective dark matter fraction f D M times a universal length that is the basic nonlocality length scale λ 0 ≈ 3 ± 2 kpc.

  7. Nonlocality and localizability in quantum mechanics

    International Nuclear Information System (INIS)

    Matsuno, K.

    1989-01-01

    Nonlocality of simultaneous spatial correlation of a quantum phenomenon as demonstrated in various versions of Einstein-Podolsky-Rosen type experiment reduces to nonlocality of the measurement apparatus in the sense that the eigen-wavefunctions for the apparatus are completely specified in a manner of being independent of whatever object it may measure. Nonlocality of the measurement apparatus however serves as no more than a good approximation to reality at best. The theoretical imposition of nonlocality of the measurement apparatus as an approximation is compatible with the actual locality of quantum mechanics that dispenses with an agent claiming globally simultaneous specifiability of boundary conditions, though the genuine locality of quantum mechanics has to be examined without employing the nonlocality of the measurement apparatus. The actual locality of quantum mechanics is intrinsically irreversible in its development

  8. Nonlocal Galileons and self-acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Gabadadze, Gregory; Yu, Siqing, E-mail: sy1430@nyu.edu

    2017-05-10

    A certain class of nonlocal theories eliminates an arbitrary cosmological constant (CC) from a universe that can be perceived as our world. Dark energy then cannot be explained by a CC; it could however be due to massive gravity. We calculate the new corrections, which originate from the nonlocal terms that eliminate the CC, to the decoupling limit Lagrangian of massive gravity. The new nonlocal terms also have internal field space Galilean symmetry and are referred here as “nonlocal Galileons.” We then study a self-accelerated solution and show that the new nonlocal terms change the perturbative stability analysis. In particular, small fluctuations are now stable and non-superluminal for some simple parameter choices, whereas for the same choices the pure massive gravity fluctuations are unstable. We also study stable spherically symmetric solutions on this background.

  9. Nonlocal Quantum Effects in Cosmology

    International Nuclear Information System (INIS)

    Dumin, Yurii V.

    2014-01-01

    Since it is commonly believed that the observed large-scale structure of the universe is an imprint of quantum fluctuations existing at the very early stage of its evolution, it is reasonable to pose the question: do the effects of quantum nonlocality, which are well established now by the laboratory studies, manifest themselves also in the early universe? We try to answer this question by utilizing the results of a few experiments, namely, with the superconducting multi-Josephson-junction loops and the ultracold gases in periodic potentials. Employing a close analogy between the above-mentioned setups and the simplest one-dimensional Friedmann-Robertson-Walker cosmological model, we show that the specific nonlocal correlations revealed in the laboratory studies might be of considerable importance also in treating the strongly nonequilibrium phase transitions of Higgs fields in the early universe. Particularly, they should substantially reduce the number of topological defects (e.g., domain walls) expected due to independent establishment of the new phases in the remote spatial regions. This gives us a hint on resolving a long-standing problem of the excessive concentration of topological defects, inconsistent with observational constraints. The same effect may be also relevant to the recent problem of the anomalous behavior of cosmic microwave background fluctuations at large angular scales

  10. A study on the cochlear view in multichannel cochlear implantees

    Energy Technology Data Exchange (ETDEWEB)

    Kweon, Dae Cheol; Kim, Jeong Hee; Kim, Seong Lyong; Kim, Hae Seong; Lee, Yong Woo [College of Medicine, Seoul National Univ., Seoul (Korea, Republic of)

    1999-04-01

    Cochlear implant poses a contraindication to the magnetic resonance imaging(MRI) process, because MRI generates artifacts, inducing an electrical current and causing device magnetization. CT is relatively expensive and the metal electrodes scatter the image. Post-implantation radiological studies using anterior-posterior transorbital, submental-vertex and lateral views, the intracochlear electrodes are not well displayed. Therefore, the authors developed a special view, which we call the cochlear view. The patient is sitting in front of a vertical device. Then the midsagittal plane is adjusted to form an angle of 15 .deg. , 30 .deg. , and 45 .deg. with the film. The flexion of the neck is adjusted to make the infraorbitomeatal line(IOML) is parallel with the transverse axis of the film. The central ray is directed to exit from the skull at point which is 3.0 cm anterior and 2.0 cm superior to the EAM(external auditory meatus). Results have shown that single radiography of the cochlear view provides sufficient information to demonstrate the position of the electrodes array and the depth of insertion in cochlear. Radiography of the cochlear view in angle of 45 .deg. is an excellent image. The cochlear view gives the greatest amount of medical information with the least radiation and lowest medical cost. It can be widely used in all cochlear implant clinics.

  11. The cochlear nuclei of snakes.

    Science.gov (United States)

    Miller, M R

    1980-08-15

    The cochlear nuclei of three burrowing snakes (Xenopeltis unicolor, Cylindrophis rufus, and Eryx johni) and three non-burrowing snakes (Epicrates cenchris, Natrix sipedon, and Pituophis catenifer) were studied. The posterior branch of the statoacoustic nerve and its posterior ganglion were destroyed and the degenerated nerve fibers and terminals traced to primary cochlear nuclei in 13 specimens of Pituophis catenifer. All these snake species possess three primary and one secondary cochlear nuclei. The primary cochlear nuclei consist of a small nucleus angularis located at the cerebello-medullary junction and a fairly large nucleus magnocellularis forming a dorsal cap over the cephalic end of the alar eminence. Nucleus magnocellularis may be subdivided into a medially placed group of rounder cells, nucleus magnocellularis medialis, and a laterally placed group of more ovate and paler-staining cells, nucleus magnocellularis lateralis. A small but well-defined secondary nucleus which showed no degenerated nerve terminals after nerve root section, nucleus laminaris, underlies the cephalic part of both nucleus magnocellularis medialis and nucleus magnocellularis lateralis. Larger and better-developed cochlear nuclei were found in burrowing species than in non-burrowing species of snakes. Of the three burrowing species studied, Xenopeltis showed the greatest development of cochlear nuclei; Eryx cochlear nuclei were not quite as large but were better differentiated than in Xenopeltis; and Cylindrophis cochlear nuclei were fairly large but not as well developed nor as well differentiated as in either Xenopeltis or Eryx. The cochlear nuclei of the three non-burrowing snakes, Epicrates, Natrix, and Pituophis, were not as large nor as well developed as those of the burrowing snakes. There is some, but not complete, correlation between cochlear development and papilla basilaris length and number of hair cells. Thus, Xenopeltis and Eryx, with well-developed cochlear nuclei

  12. COCHLEAR IMPLANTATION PREVALENCE IN ELDERLY

    Directory of Open Access Journals (Sweden)

    A. V. Starokha

    2014-01-01

    Full Text Available Current paper describes an experience of cochlear implantation in elderly. Cochlear implantation has become a widely accepted intervention in the treatment of individuals with severe-to-profound sensorineural hearing loss. Cochlear implants are now accepted as a standard of care to optimize hearing and subsequent speech development in children and adults with deafness. But cochlear implantation affects not only hearing abilities, speech perception and speech production; it also has an outstanding impact on the social life, activities and self-esteem of each patient. The aim of this study was to evaluate the cochlear implantation efficacy in elderly with severe to profound sensorineural hearing loss. There were 5 patients under our observation. Surgery was performed according to traditional posterior tympanotomy and cochleostomy for cochlear implant electrode insertion for all observed patients. The study was conducted in two stages: before speech processor’s activation and 3 months later. Pure tone free field audiometry was performed to each patient to assess the efficiency of cochlear implantation in dynamics. The aim of the study was also to evaluate quality of life in elderly with severe to profound sensorineural hearing loss after unilateral cochlear implantation. Each patient underwent questioning with 36 Item Short Form Health Survey (SF-36. SF-36 is a set of generic, coherent, and easily administered quality-of-life measures. The SF-36 consists of eight scaled scores, which are the weighted sums of the questions in their section. Each scale is directly transformed into a 0-100 scale on the assumption that each question carries equal weight. The eight sections are: physical functioning; physical role functioning; emotional role functioning; vitality; emotional well-being; social role functioning; bodily pain; general health perceptions. Our results demonstrate that cochlear implantation in elderly consistently improved quality of life

  13. Overlapping Schwarz for Nonlinear Problems. An Element Agglomeration Nonlinear Additive Schwarz Preconditioned Newton Method for Unstructured Finite Element Problems

    Energy Technology Data Exchange (ETDEWEB)

    Cai, X C; Marcinkowski, L; Vassilevski, P S

    2005-02-10

    This paper extends previous results on nonlinear Schwarz preconditioning ([4]) to unstructured finite element elliptic problems exploiting now nonlocal (but small) subspaces. The non-local finite element subspaces are associated with subdomains obtained from a non-overlapping element partitioning of the original set of elements and are coarse outside the prescribed element subdomain. The coarsening is based on a modification of the agglomeration based AMGe method proposed in [8]. Then, the algebraic construction from [9] of the corresponding non-linear finite element subproblems is applied to generate the subspace based nonlinear preconditioner. The overall nonlinearly preconditioned problem is solved by an inexact Newton method. Numerical illustration is also provided.

  14. Can EPR non-locality be geometrical?

    International Nuclear Information System (INIS)

    Ne'eman, Y.

    1995-01-01

    The presence in Quantum Mechanics of non-local correlations is one of the two fundamentally non-intuitive features of that theory. The non-local correlations themselves fall into two classes: EPR and Geometrical. The non-local characteristics of the geometrical type are well-understood and are not suspected of possibly generating acausal features, such as faster-than-light propagation of information. This has especially become true since the emergence of a geometrical treatment for the relevant gauge theories, i.e. Fiber Bundle geometry, in which the quantum non-localities are seen to correspond to pure homotopy considerations. This aspect is reviewed in section 2. Contrary-wise, from its very conception, the EPR situation was felt to be paradoxical. It has been suggested that the non-local features of EPR might also derive from geometrical considerations, like all other non-local characteristics of QM. In[7], one of the authors was able to point out several plausibility arguments for this thesis, emphasizing in particular similarities between the non-local correlations provided by any gauge field theory and those required by the preservation of the quantum numbers of the original EPR state-vector, throughout its spatially-extended mode. The derivation was, however, somewhat incomplete, especially because of the apparent difference between, on the one hand, the closed spatial loops arising in the analysis of the geometrical non-localities, from Aharonov-Bohm and Berry phases to magnetic monopoles and instantons, and on the other hand, in the EPR case, the open line drawn by the positions of the two moving decay products of the disintegrating particle. In what follows, the authors endeavor to remove this obstacle and show that as in all other QM non-localities, EPR is somehow related to closed loops, almost involving homotopy considerations. They develop this view in section 3

  15. Nonlocal postbuckling analysis of graphene sheets with initial imperfection based on first order shear deformation theory

    Science.gov (United States)

    Soleimani, Ahmad; Naei, Mohammad Hasan; Mashhadi, Mahmoud Mosavi

    In this paper, the first order shear deformation theory (FSDT) is used to investigate the postbuckling behavior of orthotropic single-layered graphene sheet (SLGS) under in-plane loadings. Nonlocal elasticity theory and von-Karman nonlinear model in combination with the isogeometric analysis (IGA) have been applied to study the postbuckling characteristics of SLGSs. In contrast to the classical model, the nonlocal continuum model developed in this work considers the size-effects on the postbuckling characteristics of SLGSs. FSDT takes into account effects of shear deformations through-the-thickness of plate. Geometric imperfection which is defined as a very small transverse displacement of the mid-plane is applied on undeformed nanoplate to create initial deviation in graphene sheet from being perfectly flat. Nonlinear governing equations of motion for SLGS are derived from the principle of virtual work and a variational formulation. At the end, the results are presented as the postbuckling equilibrium paths of SLGS. The influence of various parameters such as edge length, nonlocal parameter, compression ratio, boundary conditions and aspect ratio on the postbuckling path is investigated. The results of this work show the high accuracy of nonlocal FSDT-based analysis for postbuckling behavior of graphene sheets.

  16. Film edge nonlocal spin valves.

    Science.gov (United States)

    McCallum, Andrew T; Johnson, Mark

    2009-06-01

    Spintronics is a new paradigm for integrated digital electronics. Recently established as a niche for nonvolatile magnetic random access memory (MRAM), it offers new functionality while demonstrating low-power and high-speed performance. However, to reach high density spintronic technology must make a transition to the nanometer scale. Prototype devices are presently made using a planar geometry and have an area determined by the lithographic feature size, currently about 100 nm. Here we present a new nonplanar geometry in which one lateral dimension is given by a film thickness, on the order of 10 nm. With this new approach, cell sizes can shrink by an order of magnitude. The geometry is demonstrated with a nonlocal spin valve, where we study devices with an injector/detector separation much less than the spin diffusion length.

  17. Bell's theorem, accountability and nonlocality

    International Nuclear Information System (INIS)

    Vona, Nicola; Liang, Yeong-Cherng

    2014-01-01

    Bell's theorem is a fundamental theorem in physics concerning the incompatibility between some correlations predicted by quantum theory and a large class of physical theories. In this paper, we introduce the hypothesis of accountability, which demands that it is possible to explain the correlations of the data collected in many runs of a Bell experiment in terms of what happens in each single run. Under this assumption, and making use of a recent result by Colbeck and Renner (2011 Nature Commun. 2 411), we then show that any nontrivial account of these correlations in the form of an extension of quantum theory must violate parameter independence. Moreover, we analyze the violation of outcome independence of quantum mechanics and show that it is also a manifestation of nonlocality. This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical devoted to ‘50 years of Bell's theorem’. (paper)

  18. Cochlear implant assessment: imaging issues

    Energy Technology Data Exchange (ETDEWEB)

    Marsot-Dupuch, K. E-mail: kathlyn.marsot-dupuch@bct.ap-hop-paris.fr; Meyer, B

    2001-11-01

    Cochlear implants are electronic auditory prostheses used to rehabilitate deafened persons who have lost their hair cells. They are partly worn externally and partly implanted in the ear. They provide a direct stimulation of the spiral ganglion cells of the cochlear nerve by bypassing the destroyed hair cells. The objectives of this article are to summarise what head and neck surgeons need to know before cochlear implantation and to describe the imaging study protocol used and anomalies to look for. A few explanations are resumed about placement of a brainstem implant.

  19. Hyperbolic metamaterial lens with hydrodynamic nonlocal response

    DEFF Research Database (Denmark)

    Yan, Wei; Mortensen, N. Asger; Wubs, Martijn

    2013-01-01

    We investigate the effects of hydrodynamic nonlocal response in hyperbolic metamaterials (HMMs), focusing on the experimentally realizable parameter regime where unit cells are much smaller than an optical wavelength but much larger than the wavelengths of the longitudinal pressure waves of the f......We investigate the effects of hydrodynamic nonlocal response in hyperbolic metamaterials (HMMs), focusing on the experimentally realizable parameter regime where unit cells are much smaller than an optical wavelength but much larger than the wavelengths of the longitudinal pressure waves...... in the local-response approximation and in the hydrodynamic Drude model can differ considerably. In particular, the optimal frequency for imaging in the nonlocal theory is blueshifted with respect to that in the local theory. Thus, to detect whether nonlocal response is at work in a hyperbolic metamaterial, we...... propose to measure the near-field distribution of a hyperbolic metamaterial lens....

  20. Nanoplasmonics: Exploring nonlocal and quantum effects

    DEFF Research Database (Denmark)

    Mortensen, N. Asger

    2016-01-01

    Plasmonics is commonly understood within classical electrodynamics with local-response constitutive relations. However, possibilities for nonlocal dynamics and quantum effects emerge with strong spatial confinement in plasmonic nanostructures. This talks reviews recent theory and experiments...

  1. Employee Travel Data (Non-Local)

    Data.gov (United States)

    Montgomery County of Maryland — ‘This dataset provides information regarding the total approved actual expenses incurred by Montgomery County government employees traveling non-locally (over 75...

  2. Wavefunction Collapse via a Nonlocal Relativistic Variational Principle

    Energy Technology Data Exchange (ETDEWEB)

    Harrison, Alan K. [Los Alamos National Laboratory

    2012-06-18

    Since the origin of quantum theory in the 1920's, some of its practitioners (and founders) have been troubled by some of its features, including indeterminacy, nonlocality and entanglement. The 'collapse' process described in the Copenhagen Interpretation is suspect for several reasons, and the act of 'measurement,' which is supposed to delimit its regime of validity, has never been unambiguously defined. In recent decades, nonlocality and entanglement have been studied energetically, both theoretically and experimentally, and the theory has been reinterpreted in imaginative ways, but many mysteries remain. We propose that it is necessary to replace the theory by one that is explicitly nonlinear and nonlocal, and does not distinguish between measurement and non-measurement regimes. We have constructed such a theory, for which the phase of the wavefunction plays the role of a hidden variable via the process of zitterbewegung. To capture this effect, the theory must be relativistic, even when describing nonrelativistic phenomena. It is formulated as a variational principle, in which Nature attempts to minimize the sum of two spacetime integrals. The first integral tends to drive the solution toward a solution of the standard quantum mechanical wave equation, and also enforces the Born rule of outcome probabilities. The second integral drives the collapse process. We demonstrate that the new theory correctly predicts the possible outcomes of the electron two-slit experiment, including the infamous 'delayed-choice' variant. We observe that it appears to resolve some long-standing mysteries, but introduces new ones, including possible retrocausality (a cause later than its effect). It is not clear whether the new theory is deterministic.

  3. Existence of mild solutions of second-order neutral functional differential inclusions with nonlocal conditions in Banach spaces

    Directory of Open Access Journals (Sweden)

    S. Marshal Anthoni

    2004-01-01

    Full Text Available We study the existence of mild solutions of the nonlinear second-order neutral functional differential and integrodifferential inclusions with nonlocal conditions in Banach spaces. The results are obtained by using the theory of strongly continuous cosine families of bounded linear operators and a fixed point theorem for condensing maps due to Martelli.

  4. Existence and uniqueness of solutions of nonlocal problems for hyperbolic equation uxt=F(x,t,u,ux

    Directory of Open Access Journals (Sweden)

    L. Byszewski

    1990-01-01

    Full Text Available The aim of the paper is to give two theorems about existence and uniqueness of continuous solutions for hyperbolic nonlinear differential problems with nonlocal conditions in bounded and unbounded domains. The results obtained in this paper can be applied in the theory of elasticity with better effect than analogous known results with classical initial conditions.

  5. Cochlear implanted children: Linguistic outcomes

    OpenAIRE

    Lynce, Sofia; Marques, Sofia; Paço, João; Mineiro, Ana

    2017-01-01

    The present exploratory study aims at exploring expressive linguistics abilities of cochlear-implanted children by testing spontaneous speech samples. For this purpose, Mean Length of Utterance in words will be measured and the productive use of single grammatical morphemes will be analysed. We analysed the spontaneous speech of three deaf Portuguese children with cochlear implants and three normal-hearing children paired case by case, taking into account the chronological age, gender and par...

  6. Symmetric states: Their nonlocality and entanglement

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zizhu; Markham, Damian [CNRS LTCI, Département Informatique et Réseaux, Telecom ParisTech, 23 avenue d' Italie, CS 51327, 75214 Paris CEDEX 13 (France)

    2014-12-04

    The nonlocality of permutation symmetric states of qubits is shown via an extension of the Hardy paradox and the extension of the associated inequality. This is achieved by using the Majorana representation, which is also a powerful tool in the study of entanglement properties of symmetric states. Through the Majorana representation, different nonlocal properties can be linked to different entanglement properties of a state, which is useful in determining the usefulness of different states in different quantum information processing tasks.

  7. Meningitis as cochlear implant complication

    Directory of Open Access Journals (Sweden)

    Kosanović Rade

    2009-01-01

    Full Text Available Over the last several decades, cochlear implantation has been fully proven as the treatment for profound hearing losses. The direct electrical stimulation of the spiral ganglion hair cells through the electrode inserted in the cochlear scala tympani is the essence of the cochlear implant (CI functioning. Modern technological development has introduced unexpected technical quality possibilities of the device itself, as well as coding strategies, which further enable improved patients' rehabilitation results. Nevertheless, in spite of cochlear implantation becoming a routine surgical procedure, which has been changing lives of thousands of profoundly deaf adults and children, it has possible complications. Though rare, these complications could lead to severe, even fatal consequences. Bacterial meningitis represents one of the most severe postoperative complications. In this article, our five-year experience with cochlear implantation is shown, compared to other, much bigger, experiences. Despite severity and a potentially fatal outcome of meningitis, it has rarely been seen, and the precise connection between surgical procedure and this complication is not yet clear. Do cochlear implants increase the risk of bacterial meningitis? Are deafness-associated factors predisposing the bacterial meningitis occurrence, independently from the implant? These are the questions that the Centers for Disease Control and Prevention (CDC, the Food and Drug Administration (FDA and the CI surgeons have been facing, as well as manufacturers and patients with their families.

  8. Robust non-local median filter

    Science.gov (United States)

    Matsuoka, Jyohei; Koga, Takanori; Suetake, Noriaki; Uchino, Eiji

    2017-04-01

    This paper describes a novel image filter with superior performance on detail-preserving removal of random-valued impulse noise superimposed on natural gray-scale images. The non-local means filter is in the limelight as a way of Gaussian noise removal with superior performance on detail preservation. By referring the fundamental concept of the non-local means, we had proposed a non-local median filter as a specialized way for random-valued impulse noise removal so far. In the non-local processing, the output of a filter is calculated from pixels in blocks which are similar to the block centered at a pixel of interest. As a result, aggressive noise removal is conducted without destroying the detailed structures in an original image. However, the performance of non-local processing decreases enormously in the case of high noise occurrence probability. A cause of this problem is that the superimposed noise disturbs accurate calculation of the similarity between the blocks. To cope with this problem, we propose an improved non-local median filter which is robust to the high level of corruption by introducing a new similarity measure considering possibility of being the original signal. The effectiveness and validity of the proposed method are verified in a series of experiments using natural gray-scale images.

  9. Asymptotic properties of blow-up solutions in reaction-diffusion equations with nonlocal boundary flux

    Science.gov (United States)

    Liu, Bingchen; Dong, Mengzhen; Li, Fengjie

    2018-04-01

    This paper deals with a reaction-diffusion problem with coupled nonlinear inner sources and nonlocal boundary flux. Firstly, we propose the critical exponents on nonsimultaneous blow-up under some conditions on the initial data. Secondly, we combine the scaling technique and the Green's identity method to determine four kinds of simultaneous blow-up rates. Thirdly, the lower and the upper bounds of blow-up time are derived by using Sobolev-type differential inequalities.

  10. The influence of cochlear traveling wave and neural adaptation on auditory brainstem responses

    DEFF Research Database (Denmark)

    Junius, D.; Dau, Torsten

    2005-01-01

    . This nonlinearity in terms of temporal processing most likely reflects effects of short-term adaptation. Overall, the results of the present study further demonstrate the importance of cochlear processing for the formation of brainstem potentials. The data may provide constraints on future models of peripheral...

  11. Nonlocal response in thin-film waveguides: Loss versus nonlocality and breaking of complementarity

    DEFF Research Database (Denmark)

    Raza, Søren; Christensen, Thomas; Wubs, Martijn

    2013-01-01

    the Thomas-Fermi internal kinetic energy of the free electrons in the metal. We derive the nonlocal dispersion relations of the three waveguide structures taking into account also retardation and interband effects, and examine the delicate interplay between nonlocal response and absorption losses...

  12. Cochlear implantation in a bilateral Mondini dysplasia.

    Science.gov (United States)

    Turrini, M; Orzan, E; Gabana, M; Genovese, E; Arslan, E; Fisch, U

    1997-01-01

    We report the speech perception progress and programming procedures of a case of congenital profound deafness and bilateral Mondini dysplasia implanted with a Nucleus 20 + 2 cochlear implant at the age of six. Unclear relations between electrodes array and cochlear partition made implant programming difficult and non-standard procedures were set. Cochlear implantation may give excellent rehabilitative results also in cochleae with malformation.

  13. Sign-changing solutions for non-local elliptic equations

    Directory of Open Access Journals (Sweden)

    Huxiao Luo

    2017-07-01

    Full Text Available This article concerns the existence of sign-changing solutions for equations driven by a non-local integrodifferential operator with homogeneous Dirichlet boundary conditions, $$\\displaylines{ -\\mathcal{L}_Ku=f(x,u,\\quad x\\in \\Omega, \\cr u=0,\\quad x\\in \\mathbb{R}^n\\setminus\\Omega, }$$ where $\\Omega\\subset\\mathbb{R}^n\\; (n\\geq2$ is a bounded, smooth domain and the nonlinear term f satisfies suitable growth assumptions. By using Brouwer's degree theory and Deformation Lemma and arguing as in [2], we prove that there exists a least energy sign-changing solution. Our results generalize and improve some results obtained in [27

  14. STABLE STATIONARY STATES OF NON-LOCAL INTERACTION EQUATIONS

    KAUST Repository

    FELLNER, KLEMENS

    2010-12-01

    In this paper, we are interested in the large-time behaviour of a solution to a non-local interaction equation, where a density of particles/individuals evolves subject to an interaction potential and an external potential. It is known that for regular interaction potentials, stable stationary states of these equations are generically finite sums of Dirac masses. For a finite sum of Dirac masses, we give (i) a condition to be a stationary state, (ii) two necessary conditions of linear stability w.r.t. shifts and reallocations of individual Dirac masses, and (iii) show that these linear stability conditions imply local non-linear stability. Finally, we show that for regular repulsive interaction potential Wε converging to a singular repulsive interaction potential W, the Dirac-type stationary states ρ̄ ε approximate weakly a unique stationary state ρ̄ ∈ L∞. We illustrate our results with numerical examples. © 2010 World Scientific Publishing Company.

  15. Nonlocality and entanglement in qubit systems

    Energy Technology Data Exchange (ETDEWEB)

    Batle, J [Departament de Fisica, Universitat de les Illes Balears, 07122 Palma de Mallorca (Spain); Casas, M, E-mail: vdfsjbv4@uib.es [Departament de Fisica and IFISC-CSIC, Universitat de les Illes Balears, 07122 Palma de Mallorca (Spain)

    2011-11-04

    Nonlocality and quantum entanglement constitute two special aspects of the quantum correlations existing in quantum systems, which are of paramount importance in quantum-information theory. Traditionally, they have been regarded as identical (equivalent, in fact, for pure two qubit states, that is, Gisin's Theorem), yet they constitute different resources. Describing nonlocality by means of the violation of several Bell inequalities, we obtain by direct optimization those states of two qubits that maximally violate a Bell inequality, in terms of their degree of mixture as measured by either their participation ratio R = 1/Tr({rho}{sup 2}) or their maximum eigenvalue {lambda}{sub max}. This optimum value is obtained as well, which coincides with previous results. Comparison with entanglement is performed too. An example of an application is given in the XY model. In this novel approximation, we also concentrate on the nonlocality for linear combinations of pure states of two qubits, providing a closed form for their maximal nonlocality measure. The case of Bell diagonal mixed states of two qubits is also extensively studied. Special attention concerning the connection between nonlocality and entanglement for mixed states of two qubits is paid to the so-called maximally entangled mixed states. Additional aspects for the case of two qubits are also described in detail. Since we deal with qubit systems, we will perform an analogous study for three qubits, employing similar tools. Relation between distillability and nonlocality is explored quantitatively for the whole space of states of three qubits. We finally extend our analysis to four-qubit systems, where nonlocality for generalized Greenberger-Horne-Zeilinger states of arbitrary number of parties is computed. (paper)

  16. Non-local matrix generalizations of W-algebras

    International Nuclear Information System (INIS)

    Bilal, A.

    1995-01-01

    There is a standard way to define two symplectic (hamiltonian) structures, the first and second Gelfand-Dikii brackets, on the space of ordinary m th -order linear differential operators L=-d m +U 1 d m-1 +U 2 d m-2 +..+U m . In this paper, I consider in detail the case where the U k are nxn-matrix-valued functions, with particular emphasis on the (more interesting) second Gelfand-Dikii bracket. Of particular interest is the reduction to the symplectic submanifold U 1 =0. This reduction gives rise to matrix generalizations of (the classical version of) the non-linear W m -algebras, called V n,m -algebras. The non-commutativity of the matrices leads to non-local terms in these V n,m -algebras. I show that these algebras contain a conformal Virasoro subalgebra and that combinations W k of the U k can be formed that are nxn-matrices of conformally primary fields of spin k, in analogy with the scalar case n=1. In general however, the V m,n -algebras have a much richer structure than the W m -algebras as can be seen on the examples of the non-linear and non-local Poisson brackets {(U 2 ) ab (σ),(U 2 ) cd (σ')}, {(U 2 ) ab (σ),(W 3 ) cd (σ')} and {(W 3 ) ab (σ),(W 3 ) cd (σ')} which I work out explicitly for all m and n. A matrix Miura transformation is derived, mapping these complicated (second Gelfand-Dikii) brackets of the U k to a set of much simpler Poisson brackets, providing the analogue of the free-field representation of the W m -algebras. (orig.)

  17. Algebra of charges in the supersymmetric nonlinear sigma model

    Energy Technology Data Exchange (ETDEWEB)

    Barcelos-Neto, J.; Das, A.; Maharana, J.

    1986-03-01

    We examine the algebra of the nonlocal charges in the supersymmetric nonlinear sigma model and show that they satisfy a nonlinear algebra at the tree-level. We also discuss other interesting questions like the transformation of these charges under a supersymmetry transformation and speculate that this algebra possibly continues to hold in the full quantum theory. (orig.).

  18. Controllability of nonlocal second-order impulsive neutral stochastic functional integro-differential equations with delay and Poisson jumps

    Directory of Open Access Journals (Sweden)

    Diem Dang Huan

    2015-12-01

    Full Text Available The current paper is concerned with the controllability of nonlocal second-order impulsive neutral stochastic functional integro-differential equations with infinite delay and Poisson jumps in Hilbert spaces. Using the theory of a strongly continuous cosine family of bounded linear operators, stochastic analysis theory and with the help of the Banach fixed point theorem, we derive a new set of sufficient conditions for the controllability of nonlocal second-order impulsive neutral stochastic functional integro-differential equations with infinite delay and Poisson jumps. Finally, an application to the stochastic nonlinear wave equation with infinite delay and Poisson jumps is given.

  19. Symmetries of nonlinear ordinary differential equations: The ...

    Indian Academy of Sciences (India)

    2015-10-21

    Oct 21, 2015 ... Abstract. Lie symmetry analysis is one of the powerful tools to analyse nonlinear ordinary dif- ferential equations. We review the effectiveness of this method in terms of various symmetries. We present the method of deriving Lie point symmetries, contact symmetries, hidden symmetries, nonlocal symmetries ...

  20. Dynamic stability of functionally graded nanobeam based on nonlocal Timoshenko theory considering surface effects

    Science.gov (United States)

    Saffari, Shahab; Hashemian, Mohammad; Toghraie, Davood

    2017-09-01

    Based on nonlocal Timoshenko beam theory, dynamic stability of functionally graded (FG) nanobeam under axial and thermal loading was investigated. Surface stress effects were implemented according to Gurtin-Murdoch continuum theory. Using power law distribution for FGM and von Karman geometric nonlinearity, governing equations were derived based on Hamilton's principle. The developed nonlocal models have the capability of interpreting small scale effects. Pasternak elastic medium was employed to represent the interaction of the FG nanobeam and the surrounding elastic medium. A parametric study was conducted to focus influences of the static load factor, temperature change, gradient index, nonlocal parameter, slenderness ratio, surface effect and springs constants of the elastic medium on the dynamic instability region (DIR) of the FG beam with simply-supported boundary conditions. It was found that differences between DIRs predicted by local and nonlocal beam theories are significant for beams with lower aspect ratio. Moreover, it was observed that in contrast to high temperature environments, at low temperatures, increasing the temperature change moves the origin of the DIR to higher excitation frequency zone and leads to further stability. Considering surface stress effects shifts the DIR of FG beam to higher frequency zone, also increasing the gradient index enhances the frequency of DIR.

  1. Nonlocal discrete regularization on weighted graphs: a framework for image and manifold processing.

    Science.gov (United States)

    Elmoataz, Abderrahim; Lezoray, Olivier; Bougleux, Sébastien

    2008-07-01

    We introduce a nonlocal discrete regularization framework on weighted graphs of the arbitrary topologies for image and manifold processing. The approach considers the problem as a variational one, which consists of minimizing a weighted sum of two energy terms: a regularization one that uses a discrete weighted p-Dirichlet energy and an approximation one. This is the discrete analogue of recent continuous Euclidean nonlocal regularization functionals. The proposed formulation leads to a family of simple and fast nonlinear processing methods based on the weighted p-Laplace operator, parameterized by the degree p of regularity, the graph structure and the graph weight function. These discrete processing methods provide a graph-based version of recently proposed semi-local or nonlocal processing methods used in image and mesh processing, such as the bilateral filter, the TV digital filter or the nonlocal means filter. It works with equal ease on regular 2-D and 3-D images, manifolds or any data. We illustrate the abilities of the approach by applying it to various types of images, meshes, manifolds, and data represented as graphs.

  2. Constraining generalized non-local cosmology from Noether symmetries

    Energy Technology Data Exchange (ETDEWEB)

    Bahamonde, Sebastian [University College London, Department of Mathematics, London (United Kingdom); Capozziello, Salvatore [Universita di Napoli ' ' Federico II' ' , Dipartimento di Fisica ' ' E. Pancini' ' , Naples (Italy); Gran Sasso Science Institute, L' Aquila (Italy); Complesso di Monte Sant' Angelo, Naples (Italy); INFN Sezione di Napoli, Naples (Italy); Dialektopoulos, Konstantinos F. [Universita di Napoli ' ' Federico II' ' , Dipartimento di Fisica ' ' E. Pancini' ' , Naples (Italy); Complesso di Monte Sant' Angelo, Naples (Italy); INFN Sezione di Napoli, Naples (Italy)

    2017-11-15

    We study a generalized non-local theory of gravity which, in specific limits, can become either the curvature non-local or teleparallel non-local theory. Using the Noether symmetry approach, we find that the coupling functions coming from the non-local terms are constrained to be either exponential or linear in form. It is well known that in some non-local theories, a certain kind of exponential non-local couplings is needed in order to achieve a renormalizable theory. In this paper, we explicitly show that this kind of coupling does not need to be introduced by hand, instead, it appears naturally from the symmetries of the Lagrangian in flat Friedmann-Robertson-Walker cosmology. Finally, we find de Sitter and power-law cosmological solutions for different non-local theories. The symmetries for the generalized non-local theory are also found and some cosmological solutions are also achieved using the full theory. (orig.)

  3. The future of cochlear implants.

    Science.gov (United States)

    Wilson, B S

    1997-08-01

    Remarkable progress has been made in recent years in the design and application of processing strategies for cochlear implants. Most notably, use of the new spectral peak (SPEAK) and continuous interleaved sampling (CIS) strategies have provided large improvements in speech reception performance compared with prior strategies (NIH Consensus Statement, 1995; Skinner et al., 1994a; Wilson et al., 1991). All major manufacturers of multichannel implant systems, including Advanced Bionics Corp., Bionic Systems, Cochlear Pty. Ltd., and Med El, now offer CIS or CIS-like strategies in their speech processors. The SPEAK strategy was developed by Cochlear Pty. Ltd and continues to be one of the options available in that company's devices. The principal purpose of this editorial is to present some of the many possibilities for further improvements in performance. To the extent that such possibilities are realized, implant systems of the future may be quite different from present systems, with different processing strategies, electrode designs, telemetry features, and fitting procedures.

  4. Quantifying Bell nonlocality with the trace distance

    Science.gov (United States)

    Brito, S. G. A.; Amaral, B.; Chaves, R.

    2018-02-01

    Measurements performed on distant parts of an entangled quantum state can generate correlations incompatible with classical theories respecting the assumption of local causality. This is the phenomenon known as quantum nonlocality that, apart from its fundamental role, can also be put to practical use in applications such as cryptography and distributed computing. Clearly, developing ways of quantifying nonlocality is an important primitive in this scenario. Here, we propose to quantify the nonlocality of a given probability distribution via its trace distance to the set of classical correlations. We show that this measure is a monotone under the free operations of a resource theory and, furthermore, that it can be computed efficiently with a linear program. We put our framework to use in a variety of relevant Bell scenarios also comparing the trace distance to other standard measures in the literature.

  5. Congenitally Deafblind Children and Cochlear Implants

    DEFF Research Database (Denmark)

    Dammeyer, Jesper Herup

    2008-01-01

    There has been much research conducted demonstrating the positive benefits of cochlear implantation (CI) in children who are deaf. Research on cochlear implantation in children who are both deaf and blind, however, is lacking. The purpose of this article is to present a study of 5 congenitally...... deafblind children who received cochlear implants between 2.2 and 4.2 years of age.  Ratings of video observations were used to measure the children's early communication development with and without the use of their cochlear implants. In addition, parental interviews were used to assess the benefits...... parents perceived regarding their children's cochlear implants. Two examples are included in this article to illustrate the parents' perspectives about cochlear implantation in their deafblind children. Benefits of cochlear implantation in this cohort of children included improved attention and emotional...

  6. Biomaterials in cochlear implants

    Science.gov (United States)

    Stöver, Timo; Lenarz, Thomas

    2011-01-01

    The cochlear implant (CI) represents, for almost 25 years now, the gold standard in the treatment of children born deaf and for postlingually deafened adults. These devices thus constitute the greatest success story in the field of ‘neurobionic’ prostheses. Their (now routine) fitting in adults, and especially in young children and even babies, places exacting demands on these implants, particularly with regard to the biocompatibility of a CI’s surface components. Furthermore, certain parts of the implant face considerable mechanical challenges, such as the need for the electrode array to be flexible and resistant to breakage, and for the implant casing to be able to withstand external forces. As these implants are in the immediate vicinity of the middle-ear mucosa and of the junction to the perilymph of the cochlea, the risk exists – at least in principle – that bacteria may spread along the electrode array into the cochlea. The wide-ranging requirements made of the CI in terms of biocompatibility and the electrode mechanism mean that there is still further scope – despite the fact that CIs are already technically highly sophisticated – for ongoing improvements to the properties of these implants and their constituent materials, thus enhancing the effectiveness of these devices. This paper will therefore discuss fundamental material aspects of CIs as well as the potential for their future development. PMID:22073103

  7. Levinson's theorem for non-local interactions

    International Nuclear Information System (INIS)

    Ma Zhongqi; Dai Anying

    1987-08-01

    The Levinson theorem for a Schroedinger equation with both local and non-local symmetric potentials is studied in terms of the Sturm-Liouville theorem. A new convention for the phase shifts is applied instead of the usual one. It is proved that the usual Levinson theorem holds for the case with both local potential and non-local symmetric cutoff potential which is not necessary to be separable. The problems related with the positive energy bound states and the physical redundant states are also discussed in this paper. (author). 17 refs

  8. On nonlocal modeling in continuum mechanics

    Directory of Open Access Journals (Sweden)

    Adam Martowicz

    2018-01-01

    Full Text Available The objective of the paper is to provide an overview of nonlocal formulations for models of elastic solids. The author presents the physical foundations for nonlocal theories of continuum mechanics, followed by various analytical and numerical techniques. The characteristics and range of practical applications for the presented approaches are discussed. The results of numerical simulations for the selected case studies are provided to demonstrate the properties of the described methods. The paper is illustrated with outcomes from peridynamic analyses. Fatigue and axial stretching were simulated to show the capabilities of the developed numerical tools.

  9. Classification of scalar and dyadic nonlocal optical response models

    DEFF Research Database (Denmark)

    Wubs, Martijn

    2015-01-01

    Nonlocal optical response is one of the emerging effects on the nanoscale for particles made of metals or doped semiconductors. Here we classify and compare both scalar and tensorial nonlocal response models. In the latter case the nonlocality can stem from either the longitudinal response...

  10. Quadratic solitons for negative effective second-harmonic diffraction as nonlocal solitons with periodic nonlocal response function

    DEFF Research Database (Denmark)

    Esbensen, B.K.; Bache, Morten; Krolikowski, W.

    2012-01-01

    We employ the formal analogy between quadratic and nonlocal solitons to investigate analytically the properties of solitons and soliton bound states in second-harmonic generation in the regime of negative diffraction or dispersion of the second harmonic. We show that in the nonlocal description...... this regime corresponds to a periodic nonlocal response function. We then use the strongly nonlocal approximation to find analytical solutions of the families of single bright solitons and their bound states in terms of Mathieu functions....

  11. On nonlocal problems for ordinary differential equations and on a nonlocal parabolic transmission problem

    Directory of Open Access Journals (Sweden)

    M. Denche

    1999-01-01

    Full Text Available In the present paper we study nonlocal problems for ordinary differential equations with a discontinuous coefficient for the high order derivative. We establish sufficient conditions, known as regularity conditions, which guarantee the coerciveness for both the space variable and the spectral parameter, as well as guarantee the completeness of the system of root functions. The results obtained are then applied to the study of a nonlocal parabolic transmission problem.

  12. Reading skills after cochlear implantation

    NARCIS (Netherlands)

    Vermeulen, A.M.

    2007-01-01

    It has frequently been found that profoundly deaf children with conventional hearing aids have difficulties with the comprehension of written text. Cochlear Implants (CIs) were expected to enhance the reading comprehension of these profoundly deaf children because they provide auditory access to

  13. Quantum Nonlocality with Spins in Diamond

    NARCIS (Netherlands)

    Hensen, B.J.

    2016-01-01

    In this thesis we experimentally investigate quantum nonlocality: entangled states of spatially separated objects. Entanglement is one of the most striking consequences of the quantum formalism developed in the 1920's; the predicted outcomes of independent measurements on entangled objects reveal

  14. Nonlocal study of ultimate plasmon hybridization

    DEFF Research Database (Denmark)

    Raza, Søren; Wubs, Martijn; Bozhevolnyi, Sergey I.

    2015-01-01

    the transition from separated dimers via touching dimers to finally overlapping dimers. In particular, we focus on the touching case, showing a fundamental limit on the hybridization of the bonding plasmon modes due to nonlocality. Using transformation optics, we determine a simple analytical equation...

  15. Energy dependence of nonlocal optical potentials

    Science.gov (United States)

    Lovell, A. E.; Bacq, P.-L.; Capel, P.; Nunes, F. M.; Titus, L. J.

    2017-11-01

    Recently, a variety of studies have shown the importance of including nonlocality in the description of reactions. The goal of this work is to revisit the phenomenological approach to determining nonlocal optical potentials from elastic scattering. We perform a χ2 analysis of neutron elastic scattering data off 40Ca, 90Zr, and 208Pb at energies E ≈5 -40 MeV, assuming a Perey and Buck [Nucl. Phys. 32, 353 (1962), 10.1016/0029-5582(62)90345-0] or Tian et al. [Int. J. Mod. Phys. E 24, 1550006 (2015), 10.1142/S0218301315500068] nonlocal form for the optical potential. We introduce energy and asymmetry dependencies in the imaginary part of the potential and refit the data to obtain a global parametrization. Independently of the starting point in the minimization procedure, an energy dependence in the imaginary depth is required for a good description of the data across the included energy range. We present two parametrizations, both of which represent an improvement over the original potentials for the fitted nuclei as well as for other nuclei not included in our fit. Our results show that, even when including the standard Gaussian nonlocality in optical potentials, a significant energy dependence is required to describe elastic-scattering data.

  16. Second order evolution equations with nonlocal conditions

    Directory of Open Access Journals (Sweden)

    Benchohra Mouffak

    2017-12-01

    Full Text Available In this paper, we shall establish sufficient conditions for the existence of solutions for second order semilinear functional evolutions equation with nonlocal conditions in Fréchet spaces. Our approach is based on the concepts of Hausdorff measure, noncompactness and Tikhonoff’s fixed point theorem. We give an example for illustration.

  17. Local and nonlocal space-time singularities

    International Nuclear Information System (INIS)

    Konstantinov, M.Yu.

    1985-01-01

    The necessity to subdivide the singularities into two classes: local and nonlocal, each of them to be defined independently, is proved. Both classes of the singularities are defined, and the relation between the definitions introduced and the standard definition of singularities, based on space-time, incompleteness, is established. The relation between definitions introduced and theorems on the singularity existence is also established

  18. Nonlocal effective actions in semiclassical gravity: Thermal effects in stationary geometries

    Science.gov (United States)

    Elías, M.; Mazzitelli, F. D.; Trombetta, L. G.

    2017-11-01

    We compute the gravitational effective action by integrating out quantum matter fields in a weak gravitational field, using the Schwinger-Keldysh (in-in) formalism. We pay particular attention to the role of the initial quantum state in the structure of the nonlocal terms in the effective action, with an eye to nonlinear completions of the theory that may be relevant in astrophysics and cosmology. In this first paper we consider a quantum scalar field in thermal equilibrium, in a stationary gravitational field. We obtain a covariant expression for the nonlocal effective action, which can be expressed in terms of the curvature tensor, the four-velocity of the thermal bath, and the local Tolman temperature. We discuss the connection between the results for ultrastatic and static metrics through conformal transformations, and the main features of the thermal corrections to the semiclassical Einstein equations.

  19. Regularized finite element modeling of progressive failure in soils within nonlocal softening plasticity

    Science.gov (United States)

    Huang, Maosong; Qu, Xie; Lü, Xilin

    2017-11-01

    By solving a nonlinear complementarity problem for the consistency condition, an improved implicit stress return iterative algorithm for a generalized over-nonlocal strain softening plasticity was proposed, and the consistent tangent matrix was obtained. The proposed algorithm was embodied into existing finite element codes, and it enables the nonlocal regularization of ill-posed boundary value problem caused by the pressure independent and dependent strain softening plasticity. The algorithm was verified by the numerical modeling of strain localization in a plane strain compression test. The results showed that a fast convergence can be achieved and the mesh-dependency caused by strain softening can be effectively eliminated. The influences of hardening modulus and material characteristic length on the simulation were obtained. The proposed algorithm was further used in the simulations of the bearing capacity of a strip footing; the results are mesh-independent, and the progressive failure process of the soil was well captured.

  20. Nonlocal gravity. Conceptual aspects and cosmological predictions

    Science.gov (United States)

    Belgacem, Enis; Dirian, Yves; Foffa, Stefano; Maggiore, Michele

    2018-03-01

    Even if the fundamental action of gravity is local, the corresponding quantum effective action, that includes the effect of quantum fluctuations, is a nonlocal object. These nonlocalities are well understood in the ultraviolet regime but much less in the infrared, where they could in principle give rise to important cosmological effects. Here we systematize and extend previous work of our group, in which it is assumed that a mass scale Λ is dynamically generated in the infrared, giving rise to nonlocal terms in the quantum effective action of gravity. We give a detailed discussion of conceptual aspects related to nonlocal gravity (including causality, degrees of freedom, ambiguities related to the boundary conditions of the nonlocal operator, scenarios for the emergence of a dynamical scale in the infrared) and of the cosmological consequences of these models. The requirement of providing a viable cosmological evolution severely restricts the form of the nonlocal terms, and selects a model (the so-called RR model) that corresponds to a dynamical mass generation for the conformal mode. For such a model: (1) there is a FRW background evolution, where the nonlocal term acts as an effective dark energy with a phantom equation of state, providing accelerated expansion without a cosmological constant. (2) Cosmological perturbations are well behaved. (3) Implementing the model in a Boltzmann code and comparing with observations we find that the RR model fits the CMB, BAO, SNe, structure formation data and local H0 measurements at a level statistically equivalent to ΛCDM. (4) Bayesian parameter estimation shows that the value of H0 obtained in the RR model is higher than in ΛCDM, reducing to 2.0σ the tension with the value from local measurements. (5) The RR model provides a prediction for the sum of neutrino masses that falls within the limits set by oscillation and terrestrial experiments (in contrast to ΛCDM, where letting the sum of neutrino masses vary as a free

  1. THE EARLY INTERVENTION TENDENCY OF CHINESE CHILDREN WITH COCHLEAR IMPLANTS

    OpenAIRE

    Wu, Jiaojiao; Xie, Yuhan

    2016-01-01

    From the change of adult unilateral cochlear implantation into young children even under the age of six implant cochlear, sequential bilateral cochlear implantation, which benefit by early hearing screening and technological development of cochlear implants. It is a worldwide trend that simultaneous bilateral cochlear implantation for hearing impaired children under the age of three. Cochlear implants bring changes of education opportunities and choices for children with hearing impairment. F...

  2. [Cochlear implant treatment in Germany].

    Science.gov (United States)

    Jacob, R; Stelzig, Y

    2013-01-01

    Restoration of impaired auditory function through cochlear implant is possible, with high reliably and great success. Nevertheless, there are regular disputes between patients and insurance companies due to high costs. In Germany, approx. 1.9 Mio. people are severely hearing impaired. It can be estimated that for adequate hearing rehabilitation about 30,000 cochlear implants/year are necessary. Currently, less than 10% of those affected are offered cochlear implant. A handicap is defined if there is deviation from normal hearing for more than 6 months. This sets a time frame for the supply with cochlear implant after sudden deafness. The professional code requires to advice all medical options to a person seeking help for hearing loss. This includes benefit-risk consideration. At this point, the economic aspect plays no role. The indication for medical treatment is only subject to the treating physician and should not be modified by non-physicians or organizations. It should be noted that a supply of hearing aids is qualitatively different to the help from a cochlear implant, which provides a restoration of lost function. In social law (SGB V and IX) doctors are requested to advise and recommend all measures which contribute to normal hearing (both sides). This indicates that doctors may be prosecuted for not offering help when medically possible, just because health insurance employees did not approve the cost balance. The current situation, with insufficient medical care for the hearing impaired, needs clarifying. To do this, patients, health insurance companies, the political institutions, legislation and professional societies need to accept their responsibilities.

  3. Entanglement consumption of instantaneous nonlocal quantum measurements

    International Nuclear Information System (INIS)

    Clark, S R; Jaksch, D; Connor, A J; Popescu, S

    2010-01-01

    Relativistic causality has dramatic consequences on the measurability of nonlocal variables and poses the fundamental question of whether it is physically meaningful to speak about the value of nonlocal variables at a particular time. Recent work has shown that by weakening the role of the measurement in preparing eigenstates of the variable, it is in fact possible to measure all nonlocal observables instantaneously by exploiting entanglement. However, for these measurement schemes to succeed with certainty, an infinite amount of entanglement must be distributed initially and all this entanglement is necessarily consumed. In this work, we sharpen the characterization of instantaneous nonlocal measurements by explicitly devising schemes in which only a finite amount of the initially distributed entanglement is ever utilized. This enables us to determine an upper bound to the average consumption for the most general cases of nonlocal measurements. This includes the tasks of state verification, where the measurement verifies if the system is in a given state, and verification measurements of a general set of eigenstates of an observable. Despite its finiteness, the growth of entanglement consumption is found to display an extremely unfavourable exponential of an exponential scaling with either the number of qubits needed to contain the Schmidt rank of the target state or the total number of qubits in the system for an operator measurement. This scaling is seen to be a consequence of the combination of the generic exponential scaling of unitary decompositions combined with the highly recursive structure of our scheme required to overcome the no-signalling constraint of relativistic causality.

  4. Nonlocal astrophysics dark matter, dark energy and physical vacuum

    CERN Document Server

    Alexeev, Boris V

    2017-01-01

    Non-Local Astrophysics: Dark Matter, Dark Energy and Physical Vacuum highlights the most significant features of non-local theory, a highly effective tool for solving many physical problems in areas where classical local theory runs into difficulties. The book provides the fundamental science behind new non-local astrophysics, discussing non-local kinetic and generalized hydrodynamic equations, non-local parameters in several physical systems, dark matter, dark energy, black holes and gravitational waves. Devoted to the solution of astrophysical problems from the position of non-local physics Provides a solution for dark matter and dark energy Discusses cosmological aspects of the theory of non-local physics Includes a solution for the problem of the Hubble Universe expansion, and of the dependence of the orbital velocity from the center of gravity

  5. Nonlocal collisionless and collisional electron transport in low temperature plasmas

    Science.gov (United States)

    Kaganovich, Igor

    2009-10-01

    The purpose of the talk is to describe recent advances in nonlocal electron kinetics in low-pressure plasmas. A distinctive property of partially ionized plasmas is that such plasmas are always in a non-equilibrium state: the electrons are not in thermal equilibrium with the neutral species and ions, and the electrons are also not in thermodynamic equilibrium within their own ensemble, which results in a significant departure of the electron velocity distribution function from a Maxwellian. These non-equilibrium conditions provide considerable freedom to choose optimal plasma parameters for applications, which make gas discharge plasmas remarkable tools for a variety of plasma applications, including plasma processing, discharge lighting, plasma propulsion, particle beam sources, and nanotechnology. Typical phenomena in such discharges include nonlocal electron kinetics, nonlocal electrodynamics with collisionless electron heating, and nonlinear processes in the sheaths and in the bounded plasmas. Significant progress in understanding the interaction of electromagnetic fields with real bounded plasma created by this field and the resulting changes in the structure of the applied electromagnetic field has been one of the major achievements of the last decade in this area of research [1-3]. We show on specific examples that this progress was made possible by synergy between full scale particle-in-cell simulations, analytical models, and experiments. In collaboration with Y. Raitses, A.V. Khrabrov, Princeton Plasma Physics Laboratory, Princeton, NJ, USA; V.I. Demidov, UES, Inc., 4401 Dayton-Xenia Rd., Beavercreek, OH 45322, USA and AFRL, Wright-Patterson AFB, OH 45433, USA; and D. Sydorenko, University of Alberta, Edmonton, Canada. [4pt] [1] D. Sydorenko, A. Smolyakov, I. Kaganovich, and Y. Raitses, IEEE Trans. Plasma Science 34, 895 (2006); Phys. Plasmas 13, 014501 (2006); 14 013508 (2007); 15, 053506 (2008). [0pt] [2] I. D. Kaganovich, Y. Raitses, D. Sydorenko, and

  6. Nonlocal Theories in Continuum Mechanics

    Directory of Open Access Journals (Sweden)

    M. Jirásek

    2004-01-01

    Full Text Available The purpose of this paper is to explain why the standard continuum theory fails to properly describe certain mechanical phenomena and how the description can be improved by enrichments that incorporate the influence of gradients or weighted spatial averages of strain or of an internal variable. Three typical mechanical problems that require such enrichments are presented: (i dispersion of short elastic waves in heterogeneous or discrete media, (ii size effects in microscale elastoplasticity, in particular with the size dependence of the apparent hardening modulus, and (iii localization of strain and damage in quasibrittle structures and with the resulting transitional size effect. Problems covered in the examples encompass static and dynamic phenomena, linear and nonlinear behavior, and three constitutive frameworks, namely elasticity, plasticity and continuum damage mechanics. This shows that enrichments of the standard continuum theory can be useful in a wide range of mechanical problems. 

  7. Cochlear implant revision surgeries in children.

    Science.gov (United States)

    Amaral, Maria Stella Arantes do; Reis, Ana Cláudia Mirândola B; Massuda, Eduardo T; Hyppolito, Miguel Angelo

    2018-02-16

    The surgery during which the cochlear implant internal device is implanted is not entirely free of risks and may produce problems that will require revision surgeries. To verify the indications for cochlear implantation revision surgery for the cochlear implant internal device, its effectiveness and its correlation with certain variables related to language and hearing. A retrospective study of patients under 18 years submitted to cochlear implant Surgery from 2004 to 2015 in a public hospital in Brazil. Data collected were: age at the time of implantation, gender, etiology of the hearing loss, audiological and oral language characteristics of each patient before and after Cochlear Implant surgery and any need for surgical revision and the reason for it. Two hundred and sixty-five surgeries were performed in 236 patients. Eight patients received a bilateral cochlear implant and 10 patients required revision surgery. Thirty-two surgeries were necessary for these 10 children (1 bilateral cochlear implant), of which 21 were revision surgeries. In 2 children, cochlear implant removal was necessary, without reimplantation, one with cochlear malformation due to incomplete partition type I and another due to trauma. With respect to the cause for revision surgery, of the 8 children who were successfully reimplanted, four had cochlear calcification following meningitis, one followed trauma, one exhibited a facial nerve malformation, one experienced a failure of the cochlear implant internal device and one revision surgery was necessary because the electrode was twisted. The incidence of the cochlear implant revision surgery was 4.23%. The period following the revision surgeries revealed an improvement in the subject's hearing and language performance, indicating that these surgeries are valid in most cases. Copyright © 2018 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

  8. Cochlear implants: system design, integration, and evaluation.

    Science.gov (United States)

    Zeng, Fan-Gang; Rebscher, Stephen; Harrison, William; Sun, Xiaoan; Feng, Haihong

    2008-01-01

    As the most successful neural prosthesis, cochlear implants have provided partial hearing to more than 120000 persons worldwide; half of which being pediatric users who are able to develop nearly normal language. Biomedical engineers have played a central role in the design, integration and evaluation of the cochlear implant system, but the overall success is a result of collaborative work with physiologists, psychologists, physicians, educators, and entrepreneurs. This review presents broad yet in-depth academic and industrial perspectives on the underlying research and ongoing development of cochlear implants. The introduction accounts for major events and advances in cochlear implants, including dynamic interplays among engineers, scientists, physicians, and policy makers. The review takes a system approach to address critical issues in cochlear implant research and development. First, the cochlear implant system design and specifications are laid out. Second, the design goals, principles, and methods of the subsystem components are identified from the external speech processor and radio frequency transmission link to the internal receiver, stimulator and electrode arrays. Third, system integration and functional evaluation are presented with respect to safety, reliability, and challenges facing the present and future cochlear implant designers and users. Finally, issues beyond cochlear implants are discussed to address treatment options for the entire spectrum of hearing impairment as well as to use the cochlear implant as a model to design and evaluate other similar neural prostheses such as vestibular and retinal implants.

  9. The inferior cochlear vein: surgical aspects in cochlear implantation.

    Science.gov (United States)

    Guo, Rui; Zhang, HongLei; Chen, Wei; Zhu, XiaoQuan; Liu, Wei; Rask-Andersen, Helge

    2016-02-01

    The patency of the inferior cochlear vein (ICV) may be challenged in cochlear implantation (CI) due to its location near the round window (RW). This may be essential to consider during selection of different trajectories for electrode insertion aiming at preserving residual hearing. Venous blood from the human cochlea is drained through the ICV. The vein also drains blood from the modiolus containing the spiral ganglion neurons. Surgical interference with this vein could cause neural damage influencing CI outcome. We analyzed the topographical relationship between the RW and ICV bony channel and cochlear aqueduct (CA) from a surgical standpoint. Archival human temporal bones were further microdissected to visualize the CA and its accessory canals (AC1 and AC2). This was combined with examinations of plastic and silicone molds of the human labyrinth. Metric analyses were made using photo stereomicroscopy documenting the proximal portion of the AC1, the internal aperture of the CA and the RW. The mean distance between the AC1 and the anterior rim of the RW was 0.81 mm in bone specimens and 0.67 mm assessed in corrosion casts. The AC1 runs from the floor of the scala tympani through the otic capsule passing parallel to the CA to the posterior cranial fossa. The mean distance between the CA and AC1 canal was 0.31 and 0.25 mm, respectively.

  10. CT evaluation of preoperative cochlear implantation cochlear implantation

    International Nuclear Information System (INIS)

    Tan Xiuzhong; Zhong Lansheng; Lan Bowen; Huang Yaosheng; Du Baowen; Zhu Jian

    2004-01-01

    Objective: To evaluate CT scan as a preoperative evaluation for cochlear implantation candidates. Methods: Axial high-resolution temporal bone CT and three-dimensional reconstruction of inner ear were performed in 93 patients with sensorineural hearing loss. results: Among 81 patients with congenital sensorineural deafness, Mondini malformation was seen in 7 case (13 ears); large vestibular aqueduct syndrome (LVAS) was revealed in 5 cases (8 ears); and inner ear ossification was found in 1 case (2 ears). In 1 case (2 ears) of inner ear fibrosis, reduced cochlear signal was noted on MRI but no unremarkable findings was shown on CT scan, however, in the operation, the device could not inserted into the basal circle of the cochlea, due to fibrous obliteration. In 12 patients with post-speech deafness, chronic suppurative tympanitis was seen in 2 cases (4 ears), and inner ear ossification was revealed in 1 case (2 ears). Conclusion: CT plays an indispensable role in the pre-operative evaluation of cochlear implantation. T 2 -weighted FSE-MRI of the inner ear is a useful complementary to CT scan. (authors)

  11. Microanatomy of the cochlear hook

    Science.gov (United States)

    Kwan, Changyow Claire; Tan, Xiaodong; Stock, Stuart R.; Soriano, Carmen; Xiao, Xianghui; Richter, Claus-Peter

    2017-09-01

    Communication among humans occurs through coding and decoding of acoustic information. The inner ear or cochlea acts as a frequency analyzer and divides the acoustic signal into small frequency bands, which are processed at different sites along the cochlea. The mechano-electrical conversion is accomplished by the soft tissue structures in the cochlea. While the anatomy for most of the cochlea has been well described, a detailed description of the very high frequency and vulnerable cochlear hook region is missing. To study the cochlear hook, mice cochleae were imaged with synchrotron radiation and high-resolution reconstructions have been made from the tomographic scans. This is the first detailed description of the bony and soft tissues of the hook region of the mammalian cochlea.

  12. Affine Non-Local Means Image Denoising.

    Science.gov (United States)

    Fedorov, Vadim; Ballester, Coloma

    2017-05-01

    This paper presents an extension of the Non-Local Means denoising method, that effectively exploits the affine invariant self-similarities present in the images of real scenes. Our method provides a better image denoising result by grounding on the fact that in many occasions similar patches exist in the image but have undergone a transformation. The proposal uses an affine invariant patch similarity measure that performs an appropriate patch comparison by automatically and intrinsically adapting the size and shape of the patches. As a result, more similar patches are found and appropriately used. We show that this image denoising method achieves top-tier performance in terms of PSNR, outperforming consistently the results of the regular Non-Local Means, and that it provides state-of-the-art qualitative results.

  13. Nonlocal Operational Calculi for Dunkl Operators

    Directory of Open Access Journals (Sweden)

    Ivan H. Dimovski

    2009-03-01

    Full Text Available The one-dimensional Dunkl operator $D_k$ with a non-negative parameter $k$, is considered under an arbitrary nonlocal boundary value condition. The right inverse operator of $D_k$, satisfying this condition is studied. An operational calculus of Mikusinski type is developed. In the frames of this operational calculi an extension of the Heaviside algorithm for solution of nonlocal Cauchy boundary value problems for Dunkl functional-differential equations $P(D_ku = f$ with a given polynomial $P$ is proposed. The solution of these equations in mean-periodic functions reduces to such problems. Necessary and sufficient condition for existence of unique solution in mean-periodic functions is found.

  14. Evidence and concepts for nonlocal transport

    International Nuclear Information System (INIS)

    Callen, J.D.; Kissick, M.W.

    1997-08-01

    Up until a few years ago, most transient transport studies observed primarily diffusive plasma transport responses to fast, localized perturbations. Recently, a number of experiments have, in addition, observed nonlocal electron heat responses. Most remarkably, in cold pulse experiments the abrupt edge cooling via radiative processes can induce both a diffusive cooling response moving in from the edge, and simultaneously a rising electron temperature in the central core of tokamak plasmas--an opposite response even before the diffusive cooling from the edge reaches the center. These and other nonlocal electron heat transport conundrums from recent experiments are reviewed. Also, models and physical processes being advanced to explain these puzzling phenomena are discussed. The importance of resolving this transport enigma is emphasized

  15. Switching non-local vector median filter

    Science.gov (United States)

    Matsuoka, Jyohei; Koga, Takanori; Suetake, Noriaki; Uchino, Eiji

    2016-04-01

    This paper describes a novel image filtering method that removes random-valued impulse noise superimposed on a natural color image. In impulse noise removal, it is essential to employ a switching-type filtering method, as used in the well-known switching median filter, to preserve the detail of an original image with good quality. In color image filtering, it is generally preferable to deal with the red (R), green (G), and blue (B) components of each pixel of a color image as elements of a vectorized signal, as in the well-known vector median filter, rather than as component-wise signals to prevent a color shift after filtering. By taking these fundamentals into consideration, we propose a switching-type vector median filter with non-local processing that mainly consists of a noise detector and a noise removal filter. Concretely, we propose a noise detector that proactively detects noise-corrupted pixels by focusing attention on the isolation tendencies of pixels of interest not in an input image but in difference images between RGB components. Furthermore, as the noise removal filter, we propose an extended version of the non-local median filter, we proposed previously for grayscale image processing, named the non-local vector median filter, which is designed for color image processing. The proposed method realizes a superior balance between the preservation of detail and impulse noise removal by proactive noise detection and non-local switching vector median filtering, respectively. The effectiveness and validity of the proposed method are verified in a series of experiments using natural color images.

  16. EPR paradox, quantum nonlocality and physical reality

    Science.gov (United States)

    Kupczynski, M.

    2016-03-01

    Eighty years ago Einstein, Podolsky and Rosen demonstrated that instantaneous reduction of wave function, believed to describe completely a pair of entangled physical systems, led to EPR paradox. The paradox disappears in statistical interpretation of quantum mechanics (QM) according to which a wave function describes only an ensemble of identically prepared physical systems. QM predicts strong correlations between outcomes of measurements performed on different members of EPR pairs in far-away locations. Searching for an intuitive explanation of these correlations John Bell analysed so called local realistic hidden variable models and proved that correlations consistent with these models satisfy Bell inequalities which are violated by some predictions of QM and by experimental data. Several different local models were constructed and inequalities proven. Some eminent physicists concluded that Nature is definitely nonlocal and that it is acting according to a law of nonlocal randomness. According to these law perfectly random, but strongly correlated events, can be produced at the same time in far away locations and a local and causal explanation of their occurrence cannot be given. We strongly disagree with this conclusion and we prove the contrary by analysing in detail some influential finite sample proofs of Bell and CHSH inequalities and so called Quantum Randi Challenges. We also show how one can win so called Bell's game without violating locality of Nature. Nonlocal randomness is inconsistent with local quantum field theory, with standard model in elementary particle physics and with causal laws and adaptive dynamics prevailing in the surrounding us world. The experimental violation of Bell-type inequalities does not prove the nonlocality of Nature but it only confirms a contextual character of quantum observables and gives a strong argument against counterfactual definiteness and against a point of view according to which experimental outcomes are produced

  17. Connection between Bell nonlocality and Bayesian game theory.

    Science.gov (United States)

    Brunner, Nicolas; Linden, Noah

    2013-01-01

    In 1964, Bell discovered that quantum mechanics is a nonlocal theory. Three years later, in a seemingly unconnected development, Harsanyi introduced the concept of Bayesian games. Here we show that, in fact, there is a deep connection between Bell nonlocality and Bayesian games, and that the same concepts appear in both fields. This link offers interesting possibilities for Bayesian games, namely of allowing the players to receive advice in the form of nonlocal correlations, for instance using entangled quantum particles or more general no-signalling boxes. This will lead to novel joint strategies, impossible to achieve classically. We characterize games for which nonlocal resources offer a genuine advantage over classical ones. Moreover, some of these strategies represent equilibrium points, leading to the notion of quantum/no-signalling Nash equilibrium. Finally, we describe new types of question in the study of nonlocality, namely the consideration of nonlocal advantage given a set of Bell expressions.

  18. Traveling waves in a nonlocal, piecewise linear reaction-diffusion population model

    Science.gov (United States)

    Autry, E. A.; Bayliss, A.; Volpert, V. A.

    2017-08-01

    We consider an analytically tractable switching model that is a simplification of a nonlocal, nonlinear reaction-diffusion model of population growth where we take the source term to be piecewise linear. The form of this source term allows us to consider both the monostable and bistable versions of the problem. By transforming to a traveling frame and choosing specific kernel functions, we are able to reduce the problem to a system of algebraic equations. We construct solutions and examine the propagation speed and monotonicity of the resulting waves.

  19. Superpositions of Laguerre-Gaussian Beams in Strongly Nonlocal Left-handed Materials

    International Nuclear Information System (INIS)

    Zhong Weiping; Wang Liyang; Belic, Milivoj; Huang Tingwen

    2010-01-01

    We present beam solutions of the strongly nonlocal nonlinear Schroedinger equation in left-handed materials (LHMs). Different Laguerre-Gaussian (LG) necklace beams, such as symmetric and asymmetric single layer and multilayer necklace beams are created by the superposition of two single beams with different topological charges. Such superpositions are then propagated through LHMs, displaying linear diffraction. It is found that the superposition of two LG nm beams with opposite topological charges does not show rotational behavior and that there exists rotation for other topological charge combinations. Our theory predicts that the accessible solitons cannot exist in LHMs. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  20. Modulational instability and nonlocality management in coupled NLS systems

    International Nuclear Information System (INIS)

    Doktorov, Evgeny V; Molchan, Maxim A

    2007-01-01

    The modulational instability of two interacting waves in a nonlocal Kerr-type medium is considered analytically and numerically. For a generic choice of wave amplitudes, we give a complete description of stable/unstable regimes for zero group-velocity mismatch. It is shown that nonlocality suppresses considerably the growth rate and bandwidth of instability. For nonzero group-velocity mismatch we perform a geometrical analysis of a nonlocality management which can provide stability of waves otherwise unstable in a local medium

  1. Libyan cochlear implant programme: achievements, difficulties, and ...

    African Journals Online (AJOL)

    Cochlear implantation has become established worldwide as a safe and effective method of auditory rehabilitation of selected severely and profound deaf children and adults. Over 100,000 patients have received cochlear implants worldwide with the paediatric population proving to be the main beneficiaries. The Libyan ...

  2. Survey on nonlocal games and operator space theory

    Energy Technology Data Exchange (ETDEWEB)

    Palazuelos, Carlos, E-mail: cpalazue@mat.ucm.es [Instituto de Ciencias Matemáticas (ICMAT), Facultad de Ciencias Matemáticas, Universidad Complutense de Madrid, Madrid (Spain); Vidick, Thomas, E-mail: vidick@cms.caltech.edu [Department of Computing and Mathematical Sciences, California Institute of Technology, Pasadena, California 91125 (United States)

    2016-01-15

    This review article is concerned with a recently uncovered connection between operator spaces, a noncommutative extension of Banach spaces, and quantum nonlocality, a striking phenomenon which underlies many of the applications of quantum mechanics to information theory, cryptography, and algorithms. Using the framework of nonlocal games, we relate measures of the nonlocality of quantum mechanics to certain norms in the Banach and operator space categories. We survey recent results that exploit this connection to derive large violations of Bell inequalities, study the complexity of the classical and quantum values of games and their relation to Grothendieck inequalities, and quantify the nonlocality of different classes of entangled states.

  3. Survey on nonlocal games and operator space theory

    International Nuclear Information System (INIS)

    Palazuelos, Carlos; Vidick, Thomas

    2016-01-01

    This review article is concerned with a recently uncovered connection between operator spaces, a noncommutative extension of Banach spaces, and quantum nonlocality, a striking phenomenon which underlies many of the applications of quantum mechanics to information theory, cryptography, and algorithms. Using the framework of nonlocal games, we relate measures of the nonlocality of quantum mechanics to certain norms in the Banach and operator space categories. We survey recent results that exploit this connection to derive large violations of Bell inequalities, study the complexity of the classical and quantum values of games and their relation to Grothendieck inequalities, and quantify the nonlocality of different classes of entangled states

  4. Nonlocal effects on dynamic damage accumulation in brittle solids

    Energy Technology Data Exchange (ETDEWEB)

    Chen, E.P.

    1995-12-01

    This paper presents a nonlocal analysis of the dynamic damage accumulation processes in brittle solids. A nonlocal formulation of a microcrack based continuum damage model is developed and implemented into a transient dynamic finite element computer code. The code is then applied to the study of the damage accumulation process in a concrete plate with a central hole and subjected to the action of a step tensile pulse applied at opposite edges of the plate. Several finite element discretizations are used to examine the mesh size effect. Comparisons between calculated results based on local and nonlocal formulations are made and nonlocal effects are discussed.

  5. Nonlocal Transport in the Reversed Field Pinch

    Energy Technology Data Exchange (ETDEWEB)

    Spizzo, G.; White, R. B.; Cappello, S.; Marrelli, L.

    2009-09-21

    Several heuristic models for nonlocal transport in plasmas have been developed, but they have had a limited possibility of detailed comparision with experimental data. Nonlocal aspects introduced by the existence of a known spectrum of relatively stable saturated tearing modes in a low current reversed field pinch offers a unique possibility for such a study. A numerical modelling of the magnetic structure and associated particle transport is carried out for the reversed-field pinch experiment at the Consorzio RFX, Padova, Italy. A reproduction of the tearing mode spectrum with a guiding center code1 reliably reproduces the observed soft X-ray tomography. Following particle trajectories in the stochastic magnetic field shows the transport across the unperturbed flux surfaces to be due to a spectrum of Levy flights, with the details of the spectrum position dependent. The resulting transport is subdiffusive, and cannot be described by Rechester-Rosenbluth diffusion, which depends on a random phase approximation. If one attempts to fit the local transport phenomenologically, the subdiffusion can be fit with a combination of diffusion and inward pinch2. It is found that whereas passing particles explore the stochastic field and hence participate in Levy flights, the trapped particles experience normal neoclassical diffusion. A two fluid nonlocal Montroll equation is used to model this transport, with a Levy flight defined as the motion of an ion during the period that the pitch has one sign. The necessary input to the Montroll equation consists of a time distribution for the Levy flights, given by the pitch angle scattering operator, and a distribution of the flight distances, determined numerically using a guiding center code. Results are compared to experiment. The relation of this formulation to fractional kinetics is also described.

  6. Nonlocal Transport in the Reversed Field Pinch

    International Nuclear Information System (INIS)

    Spizzo, G.; White, R.B.; Cappello, S.; Marrelli, L.

    2009-01-01

    Several heuristic models for nonlocal transport in plasmas have been developed, but they have had a limited possibility of detailed comparison with experimental data. Nonlocal aspects introduced by the existence of a known spectrum of relatively stable saturated tearing modes in a low current reversed field pinch offers a unique possibility for such a study. A numerical modeling of the magnetic structure and associated particle transport is carried out for the reversed-field pinch experiment at the Consorzio RFX, Padova, Italy. A reproduction of the tearing mode spectrum with a guiding center code1 reliably reproduces the observed soft X-ray tomography. Following particle trajectories in the stochastic magnetic field shows the transport across the unperturbed flux surfaces to be due to a spectrum of Levy flights, with the details of the spectrum position dependent. The resulting transport is subdiffusive, and cannot be described by Rechester-Rosenbluth diffusion, which depends on a random phase approximation. If one attempts to fit the local transport phenomenologically, the subdiffusion can be fit with a combination of diffusion and inward pinch. It is found that whereas passing particles explore the stochastic field and hence participate in Levy flights, the trapped particles experience normal neoclassical diffusion. A two fluid nonlocal Montroll equation is used to model this transport, with a Levy flight defined as the motion of an ion during the period that the pitch has one sign. The necessary input to the Montroll equation consists of a time distribution for the Levy flights, given by the pitch angle scattering operator, and a distribution of the flight distances, determined numerically using a guiding center code. Results are compared to experiment. The relation of this formulation to fractional kinetics is also described.

  7. Cochlear infrastructure for electrical hearing

    Science.gov (United States)

    Pfingst, Bryan E.; Bowling, Sara A.; Colesa, Deborah J.; Garadat, Soha N.; Raphael, Yehoash; Shibata, Seiji B.; Strahl, Stefan B.; Su, Gina L.; Zhou, Ning

    2011-01-01

    Although the cochlear implant is already the world's most successful neural prosthesis, opportunities for further improvement abound. Promising areas of current research include work on improving the biological infrastructure in the implanted cochlea to optimize reception of cochlear implant stimulation and on designing the pattern of electrical stimulation to take maximal advantage of conditions in the implanted cochlea. In this review we summarize what is currently known about conditions in the cochlea of deaf, implanted humans and then review recent work from our animal laboratory investigating the effects of preserving or reinnervating tissues on psychophysical and electrophysiological measures of implant function. Additionally we review work from our human laboratory on optimizing the pattern of electrical stimulation to better utilize strengths in the cochlear infrastructure. Histological studies of human temporal bones from implant users and from people who would have been candidates for implants show a range of pathologic conditions including spiral ganglion cell counts ranging from approximately 2% to 92% of normal and partial hair cell survival in some cases. To duplicate these conditions in a guinea pig model, we use a variety of deafening and implantation procedures as well as post1-deafening therapies designed to protect neurons and/or regenerate neurites. Across populations of human patients, relationships between nerve survival and functional measures such as speech have been difficult to demonstrate, possibly due to the numerous subject variables that can affect implant function and the elapsed time between functional measures and postmortem histology. However, psychophysical studies across stimulation sites within individual human subjects suggest that biological conditions near the implanted electrodes contribute significantly to implant function, and this is supported by studies in animal models comparing histological findings to psychophysical

  8. Pion polarizability in nonlocal quark model

    International Nuclear Information System (INIS)

    Efimov, G.V.; Okhlopkova, V.A.

    1978-01-01

    The γγ→ππ amplitude was calculated in nonlocal quark model in the fourth order on the perturbation theory. The coefficients of electric[a) and magnetic polarizability (β) determined are equal in magnitude and opposite in sign αsub(π+-)=βsub(π+-)=+0.014α/msub(π)sup(3), αsub(πsup(0))=-βsub(πsup(0))=-0.07α/msub(π)sup(3). The results have been compared with calculations in other models

  9. Nonlocal inhomogeneous broadening in plasmonic nanoparticle ensembles

    DEFF Research Database (Denmark)

    Tserkezis, Christos; Maack, Johan Rosenkrantz; Liu, Z.

    is to abandon the local response approximation (LRA) and take the nonlocal response of the metal into account, typically through the simple hydrodynamic Drude model (HDM), which predicts a sizedependent deviation of plasmon modes from the quasistatic (QS) limit. While this behaviour has been explored for simple......Nonclassical effects are increasingly more relevant in plasmonics as modern nanofabrication techniques rapidly approach the extreme nanoscale limits, for which departing from classical electrodynamics becomes important. One of the largest-scale necessary corrections towards this direction...

  10. Non-local modeling of materials

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof

    2002-01-01

    Numerical studies of non-local plasticity effects on different materials and problems are carried out. Two different theories are used. One is of lower order in that it retains the structure of a conventional plasticity boundary value problem, while the other is of higher order and employs higher...... order stresses as work conjugates to higher order strains and uses higher order boundary conditions. The influence of internal material length parameters is studied, and the effects of higher order boundary conditions are analyzed. The focus of the thesis is on metal-matrix composites, and non...

  11. Audiovisual segregation in cochlear implant users.

    Directory of Open Access Journals (Sweden)

    Simon Landry

    Full Text Available It has traditionally been assumed that cochlear implant users de facto perform atypically in audiovisual tasks. However, a recent study that combined an auditory task with visual distractors suggests that only those cochlear implant users that are not proficient at recognizing speech sounds might show abnormal audiovisual interactions. The present study aims at reinforcing this notion by investigating the audiovisual segregation abilities of cochlear implant users in a visual task with auditory distractors. Speechreading was assessed in two groups of cochlear implant users (proficient and non-proficient at sound recognition, as well as in normal controls. A visual speech recognition task (i.e. speechreading was administered either in silence or in combination with three types of auditory distractors: i noise ii reverse speech sound and iii non-altered speech sound. Cochlear implant users proficient at speech recognition performed like normal controls in all conditions, whereas non-proficient users showed significantly different audiovisual segregation patterns in both speech conditions. These results confirm that normal-like audiovisual segregation is possible in highly skilled cochlear implant users and, consequently, that proficient and non-proficient CI users cannot be lumped into a single group. This important feature must be taken into account in further studies of audiovisual interactions in cochlear implant users.

  12. Nonlinear dynamics of semiclassical coherent states in periodic potentials

    International Nuclear Information System (INIS)

    Carles, Rémi; Sparber, Christof

    2012-01-01

    We consider nonlinear Schrödinger equations with either local or nonlocal nonlinearities. In addition, we include periodic potentials as used, for example, in matter wave experiments in optical lattices. By considering the corresponding semiclassical scaling regime, we construct asymptotic solutions, which are concentrated both in space and in frequency around the effective semiclassical phase-space flow induced by Bloch’s spectral problem. The dynamics of these generalized coherent states is governed by a nonlinear Schrödinger model with effective mass. In the case of nonlocal nonlinearities, we establish a novel averaging-type result in the critical case. This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical devoted to ‘Coherent states: mathematical and physical aspects’. (paper)

  13. The Center for Nonlinear Phenomena and Magnetic Materials

    Science.gov (United States)

    1992-09-30

    isotopies of contemporary mathematical structures. Outline of: isounits; isofields; isovector and isometric spaces (isoeuclidean. isominkowski and...geometries; isoparallel transport and isogeodesics; axioms-preserving isotopies of classical Hamiltonian mechanics (Birkhoffian mechanics); axioms...preserving isotopies of quantum mechanics (hadronic mechanics). Outline of isogravitations as the most general known nonlinear, nonlocal and nonlagrangian

  14. Existence of solutions of nonlinear integrodifferential equations of ...

    Indian Academy of Sciences (India)

    a nonlinear integrodifferential equation of Sobolev type with nonlocal condition. The results are ... gated the same type of problem to different classes of abstract differential equations in. Banach spaces [1±4, 8, 11, 13, ..... [2] Balachandran K and Chandrasekaran M, Existence of solutions of a delay differential equation with ...

  15. Discussion record of the workshop on nonlocal transport

    International Nuclear Information System (INIS)

    Itoh, K.; Itoh, S.-I.; Stroth, U.; Iwasaki, T.; Yagi, M.; Fukuyama, A.

    1997-06-01

    The discussion on the problem of the transient response and nonlocal transport is reported. Problem of the transient response is surveyed, and several approaches are reviewed. The formulation based on the nonlocal transport is discussed. Example of the analysis is presented. Future study is identified. (author)

  16. Incompressible turbulence as non-local field theory

    Indian Academy of Sciences (India)

    Abstract. It is well-known that incompressible turbulence is non-local in real space because sound speed is infinite in incompressible fluids. The equation in Fourier space indicates that it is non-local in Fourier space as well. However, the shell-to-shell energy transfer is local. Contrast this with Burgers equation which is local ...

  17. Cochlear otosclerosis(otospongiosis) : a case report

    Energy Technology Data Exchange (ETDEWEB)

    Youn, Eun Kyung [Kanbuk Samsung Hospital Samsung Medical Center, Seoul (Korea, Republic of)

    1996-06-01

    Otosclerosis occurs when normal ivory-like endochondral bone of the otic capsule is replaced by foci of spongy vascular irregular new bone. Eventually these foci of haversian bone became more solid. There are two types of otosclerosis : fenestral and retrofenestral or cochlear. The cochlear type is much less common and rarely occurs without fenestral involvement. Otosclerosis occurs very rarely in blacks and orientals ; in otolaryngologic articles in Korea there are few reports of otosclerosis, and then only the fenestral type. This is a case report of cochlear otosclerosis that can be diagnosed on temporal bone CT.

  18. Pacemakers in large arrays of oscillators with nonlocal coupling

    Science.gov (United States)

    Jaramillo, Gabriela; Scheel, Arnd

    2016-02-01

    We model pacemaker effects of an algebraically localized heterogeneity in a 1 dimensional array of oscillators with nonlocal coupling. We assume the oscillators obey simple phase dynamics and that the array is large enough so that it can be approximated by a continuous nonlocal evolution equation. We concentrate on the case of heterogeneities with positive average and show that steady solutions to the nonlocal problem exist. In particular, we show that these heterogeneities act as a wave source. This effect is not possible in 3 dimensional systems, such as the complex Ginzburg-Landau equation, where the wavenumber of weak sources decays at infinity. To obtain our results we use a series of isomorphisms to relate the nonlocal problem to the viscous eikonal equation. We then use Fredholm properties of the Laplace operator in Kondratiev spaces to obtain solutions to the eikonal equation, and by extension to the nonlocal problem.

  19. Origin and effect of nonlocality in a layered composite.

    Energy Technology Data Exchange (ETDEWEB)

    Silling, Stewart Andrew

    2014-01-01

    A simple demonstration of nonlocality in a heterogeneous material is presented. By analysis of the microscale deformation of a two-component layered medium, it is shown that nonlocal interactions necessarily appear in a homogenized model of the system. Explicit expressions for the nonlocal forces are determined. The way these nonlocal forces appear in various nonlocal elasticity theories is derived. The length scales that emerge involve the constituent material properties as well as their geometrical dimen- sions. A peridynamic material model for the smoothed displacement eld is derived. It is demonstrated by comparison with experimental data that the incorporation of non- locality in modeling dramatically improves the prediction of the stress concentration in an open hole tension test on a composite plate.

  20. A new treatment of nonlocality in scattering process

    Science.gov (United States)

    Upadhyay, N. J.; Bhagwat, A.; Jain, B. K.

    2018-01-01

    Nonlocality in the scattering potential leads to an integro-differential equation. In this equation nonlocality enters through an integral over the nonlocal potential kernel. The resulting Schrödinger equation is usually handled by approximating r,{r}{\\prime }-dependence of the nonlocal kernel. The present work proposes a novel method to solve the integro-differential equation. The method, using the mean value theorem of integral calculus, converts the nonhomogeneous term to a homogeneous term. The effective local potential in this equation turns out to be energy independent, but has relative angular momentum dependence. This method is accurate and valid for any form of nonlocality. As illustrative examples, the total and differential cross sections for neutron scattering off 12C, 56Fe and 100Mo nuclei are calculated with this method in the low energy region (up to 10 MeV) and are found to be in reasonable accord with the experiments.

  1. Feature-Based Nonlocal Polarimetric SAR Filtering

    Directory of Open Access Journals (Sweden)

    Xiaoli Xing

    2017-10-01

    Full Text Available Polarimetric synthetic aperture radar (PolSAR images are inherently contaminated by multiplicative speckle noise, which complicates the image interpretation and image analyses. To reduce the speckle effect, several adaptive speckle filters have been developed based on the weighted average of the similarity measures commonly depending on the model or probability distribution, which are often affected by the distribution parameters and modeling texture components. In this paper, a novel filtering method introduces the coefficient of variance ( CV and Pauli basis (PB to measure the similarity, and the two features are combined with the framework of the nonlocal mean filtering. The CV is used to describe the complexity of various scenes and distinguish the scene heterogeneity; moreover, the Pauli basis is able to express the polarimetric information in PolSAR image processing. This proposed filtering combines the CV and Pauli basis to improve the estimation accuracy of the similarity weights. Then, the similarity of the features is deduced according to the test statistic. Subsequently, the filtering is proceeded by using the nonlocal weighted estimation. The performance of the proposed filter is tested with the simulated images and real PolSAR images, which are acquired by AIRSAR system and ESAR system. The qualitative and quantitative experiments indicate the validity of the proposed method by comparing with the widely-used despeckling methods.

  2. Cochlear Implant Using Neural Prosthetics

    Science.gov (United States)

    Gupta, Shweta; Singh, Shashi kumar; Dubey, Pratik Kumar

    2012-10-01

    This research is based on neural prosthetic device. The oldest and most widely used of these electrical, and often computerized, devices is the cochlear implant, which has provided hearing to thousands of congenitally deaf people in this country. Recently, the use of the cochlear implant is expanding to the elderly, who frequently suffer major hearing loss. More cutting edge are artificial retinas, which are helping dozens of blind people see, and ìsmartî artificial arms and legs that amputees can maneuver by thoughts alone, and that feel more like real limbs.Research, which curiosity led to explore frog legs dancing during thunderstorms, a snail shapedorgan in the inner ear, and how various eye cells react to light, have fostered an understanding of how to ìtalkî to the nervous system. That understanding combined with the miniaturization of electronics and enhanced computer processing has enabled prosthetic devices that often can bridge the gap in nerve signaling that is caused by disease or injury.

  3. Is All Human Hearing Cochlear?

    Directory of Open Access Journals (Sweden)

    Seyede Faranak Emami

    2013-01-01

    Full Text Available The objective of this cross-sectional study was to investigate the possibility that the saccule may contribute to human hearing. The forty participants included twenty healthy people and twenty other subjects selected from patients who presented with benign paroxysmal positional vertigo to Audiology Department of Hazrat Rasoul Akram hospital (Tehran, Iran. Assessments comprised of audiological evaluations, cervical vestibular evoked myogenic potentials (cVEMPs, recognition of spoken phonemes in white noise (Rsp in wn, and auditory brainstem response to 500 Hz tone burst (ABR500 HZ. Twenty affected ears with decreased vestibular excitability as detected by abnormal cVEMPs revealed decreased scores of Rsp in wn and abnormal findings of ABR500 HZ. Both unaffected and normal ears had normal results. Multiple comparisons of mean values of cVEMPs and ABR500 HZ between three groups were significant (P<0.05, ANOVA. The correlation between RSP in wn and p13 latencies was significant. The peak-to-peak amplitudes showed significant correlation to RSP in wn. The correlation between RSP in wn and the latencies of n23 was significant. In high-level of noisy competing situations, healthy human saccular sensation can mediate the detection of low frequencies and possibly help in cochlear hearing for frequency and intensity discrimination. So, all human hearing is not cochlear.

  4. Bistable near field and bistable transmittance in 2D composite slab consisting of nonlocal core-Kerr shell inclusions.

    Science.gov (United States)

    Huang, Yang; Wu, Ya Min; Gao, Lei

    2017-01-23

    We carry out a theoretical study on optical bistability of near field intensity and transmittance in two-dimensional nonlinear composite slab. This kind of 2D composite is composed of nonlocal metal/Kerr-type dielectric core-shell inclusions randomly embedded in the host medium, and we derivate the nonlinear relation between the field intensity in the shell of inclusions and the incident field intensity with self-consistent mean field approximation. Numerical demonstration has been performed to show the viable parameter space for the bistable near field. We show that nonlocality can provide broader region in geometric parameter space for bistable near field as well as bistable transmittance of the nonlocal composite slab compared to local case. Furthermore, we investigate the bistable transmittance in wavelength spectrum, and find that besides the input intensity, the wavelength operation could as well make the transmittance jump from a high value to a low one. This kind of self-tunable nano-composite slab might have potential application in optical switching devices.

  5. Cochlear implant: what the radiologist should know

    International Nuclear Information System (INIS)

    Gomes, Natalia Delage; Couto, Caroline Laurita Batista; Gaiotti, Juliana Oggioni; Costa, Ana Maria Doffemond; Ribeiro, Marcelo Almeida; Diniz, Renata Lopes Furletti Caldeira

    2013-01-01

    Cochlear implant is the method of choice in the treatment of deep sensorineural hypoacusis, particularly in patients where conventional amplification devices do not imply noticeable clinical improvement. Imaging findings are crucial in the indication or contraindication for such surgical procedure. In the assessment of the temporal bone, radiologists should be familiar with relative or absolute contraindication factors, as well as with factors that might significantly complicate the implantation. Some criteria such as cochlear nerve aplasia, labyrinthine and/or cochlear aplasia are still considered as absolute contraindications, in spite of studies bringing such criteria into question. Cochlear dysplasias constitute relative contraindications, among them labyrinthitis ossificans is highlighted. Other alterations may be mentioned as complicating agents in the temporal bone assessment, namely, hypoplasia of the mastoid process, aberrant facial nerve, otomastoiditis, otosclerosis, dehiscent jugular bulb, enlarged endolymphatic duct and sac. The experienced radiologist assumes an important role in the evaluation of this condition. (author)

  6. Cochlear implant: what the radiologist should know

    Directory of Open Access Journals (Sweden)

    Natalia Delage Gomes

    2013-06-01

    Full Text Available Cochlear implant is the method of choice in the treatment of deep sensorineural hypoacusis, particularly in patients where conventional amplification devices do not imply noticeable clinical improvement. Imaging findings are crucial in the indication or contraindication for such surgical procedure. In the assessment of the temporal bone, radiologists should be familiar with relative or absolute contraindication factors, as well as with factors that might significantly complicate the implantation. Some criteria such as cochlear nerve aplasia, labyrinthine and/or cochlear aplasia are still considered as absolute contraindications, in spite of studies bringing such criteria into question. Cochlear dysplasias constitute relative contraindications, among them labyrinthitis ossificans is highlighted. Other alterations may be mentioned as complicating agents in the temporal bone assessment, namely, hypoplasia of the mastoid process, aberrant facial nerve, otomastoiditis, otosclerosis, dehiscent jugular bulb, enlarged endolymphatic duct and sac. The experienced radiologist assumes an important role in the evaluation of this condition.

  7. Cochlear anatomy: CT and MR imaging

    International Nuclear Information System (INIS)

    Martinez, Manuel; Bruno, Claudio; Martin, Eduardo; Canale, Nancy; De Luca, Laura; Spina, Juan C. h

    2002-01-01

    The authors present a brief overview of the normal cochlear anatomy with CT and MR images in order to allow a more complete identification of the pathological findings in patients with perceptive hipoacusia. (author)

  8. Communication development of children with cochlear implantant

    OpenAIRE

    Beznosková, Michaela

    2008-01-01

    This diploma work is devoted to the development of the communication of children with cochlear implantant. The first part (Issue) engages in problems of auditory defects and their diagnosis, which is important for the right and timeous compensation of the auditory defect. Another chapter is devoted to cochlear implantions, choice of acceptable candidates with intention to children. In the following parts the work is aimed at comunication and development of the speech. Big attention is devoted...

  9. [Cochlear implantation through the middle fossa approach].

    Science.gov (United States)

    Szyfter, W; Colletti, V; Pruszewicz, A; Kopeć, T; Szymiec, E; Kawczyński, M; Karlik, M

    2001-01-01

    The inner part of cochlear implant is inserted into inner ear during surgery through mastoid and middle ear. It is a classical method, used in the majority cochlear centers in the world. This is not a suitable method in case of chronic otitis media and middle ear malformation. In these cases Colletti proposed the middle fossa approach and cochlear implant insertion omitting middle ear structures. In patient with bilateral chronic otitis media underwent a few ears operations without obtaining dry postoperative cavity. Cochlear implantation through the middle fossa approach was performed in this patient. The bone fenster was cut, temporal lobe was bent and petrosus pyramid upper surface was exposed. When the superficial petrosal greater nerve, facial nerve and arcuate eminence were localised, the cochlear was open in the basal turn and electrode were inserted. The patient achieves good results in the postoperative speech rehabilitation. It confirmed Colletti tesis that deeper electrode insertion in the cochlear implantation through the middle fossa approach enable use of low and middle frequencies, which are very important in speech understanding.

  10. Massive Tension Pneumocephalus Following Cochlear Implant Surgery.

    Science.gov (United States)

    Di Lella, Filippo; D'Angelo, Giulia; Iaccarino, Ilaria; Piccinini, Silvia; Negri, Maurizio; Vincenti, Vincenzo

    2016-10-01

    To report clinical presentation, management and outcomes of a rare complication of cochlear implant surgery. A 68-year-old man, affected by profound bilateral deafness because of superficial cerebral hemosiderosis, presented to Authors' Department 8 days after cochlear implant surgery with vomiting, fever, and mental confusion. Brain computed tomographic (CT) scan showed a massive collection of intracranial air from an osteodural defect in the right tegmen mastoideum because of repeated nose blowing in the postoperative period. A multilayer reconstruction of the tegmen with obliteration of the mastoid cavity using abdominal subcutaneous adipose tissue was performed, preserving the cochlear implant in place. Following surgery the patient showed rapid neurological improvement and CT scan performed 2 days later showed complete resolution of the intracranial air collection. He is currently using the cochlear implant with open set performances. Pneumocephalus is a rare complication of cochlear implant surgery. In patients with severe neurological signs following cochlear implantation (CI), pneumocephalus should be suspected. Drilling of mastoid air cells may expose dura mater and positive high pressure events may break meningeal layers and force air into the cranial cavity.

  11. Mermin Non-Locality in Abstract Process Theories

    Directory of Open Access Journals (Sweden)

    Stefano Gogioso

    2015-11-01

    Full Text Available The study of non-locality is fundamental to the understanding of quantum mechanics. The past 50 years have seen a number of non-locality proofs, but its fundamental building blocks, and the exact role it plays in quantum protocols, has remained elusive. In this paper, we focus on a particular flavour of non-locality, generalising Mermin's argument on the GHZ state. Using strongly complementary observables, we provide necessary and sufficient conditions for Mermin non-locality in abstract process theories. We show that the existence of more phases than classical points (aka eigenstates is not sufficient, and that the key to Mermin non-locality lies in the presence of certain algebraically non-trivial phases. This allows us to show that fRel, a favourite toy model for categorical quantum mechanics, is Mermin local. We show Mermin non-locality to be the key resource ensuring the device-independent security of the HBB CQ (N,N family of Quantum Secret Sharing protocols. Finally, we challenge the unspoken assumption that the measurements involved in Mermin-type scenarios should be complementary (like the pair X,Y, opening the doors to a much wider class of potential experimental setups than currently employed. In short, we give conditions for Mermin non-locality tests on any number of systems, where each party has an arbitrary number of measurement choices, where each measurement has an arbitrary number of outcomes and further, that works in any abstract process theory.

  12. Effects of nonlocal potentials on (p ,d ) transfer reactions

    Science.gov (United States)

    Ross, A.; Titus, L. J.; Nunes, F. M.; Mahzoon, M. H.; Dickhoff, W. H.; Charity, R. J.

    2015-10-01

    Background: Although local phenomenological optical potentials have been standardly used to interpret nuclear reactions, recent studies suggest the effects of nonlocality should not be neglected. Purpose: In this work we investigate the effects of nonlocality in (p ,d ) transfer reactions using nonlocal optical potentials. We compare results obtained with the dispersive optical model to those obtained using the Perey-Buck interaction. Method: We solve the scattering and bound-state equations for the nonlocal version of the dispersive optical model. Then, using the distorted-wave Born approximation, we calculate the transfer cross section for (p ,d ) on 40Ca at Ep=20 , 35, and 50 MeV. Results: The inclusion of nonlocality in the bound state has a larger effect than that in the scattering states. The overall effect on the transfer cross section is very significant. We found an increase due to nonlocality in the transfer cross section of ≈30 - 50 % when using the Perey-Buck interaction and of ≈15 - 50 % when using the dispersive optical potential. Conclusions: Although the details of the nonlocal interaction can change the magnitude of the effects, our study shows that qualitatively the results obtained using the dispersive optical potential and the Perey-Buck interaction are consistent, in both cases the transfer cross sections are significantly increased.

  13. Cochlear implants in Belgium: Prevalence in paediatric and adult cochlear implantation.

    Science.gov (United States)

    De Raeve, L

    2016-06-01

    Belgium, and especially the northern region called Flanders, has been a centre of expertise in cochlear implants and early hearing screening for many years. Cochlear implants are reimbursed by the Belgian National Institute for Health and Disability (BNIHD) Insurance in adults and in children since October 1994. More than 20 years later, we would like to measure the prevalence of cochlear implants in adults and in children till now. Based on scientific research data on the prevalence of severe to profound hearing loss in adults and in children and on the number of implantations from the data of the BNIHD, we could measure the percentages of paediatric and adult CI users in comparing to the number of CI candidates. The degree of utilisation of cochlear implantation varies considerably between the paediatric and the adult population. On average, 78% of deaf children are receiving cochlear implants, but in adults only 6.6% of CI candidates are receiving one. There are big differences in Belgium in utilisation of cochlear implants between adults and children. Because of the underutilisation of cochlear implants, especially in adults, we have to work on raising the general awareness of the benefits of cochlear implants, and its improvement in quality of life, based on cost-effectiveness data and on guidelines for good clinical practice. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  14. Nonlocal kinetic-energy-density functionals

    International Nuclear Information System (INIS)

    Garcia-Gonzalez, P.; Alvarellos, J.E.; Chacon, E.

    1996-01-01

    In this paper we present nonlocal kinetic-energy functionals T[n] within the average density approximation (ADA) framework, which do not require any extra input when applied to any electron system and recover the exact kinetic energy and the linear response function of a homogeneous system. In contrast with previous ADA functionals, these present good behavior of the long-range tail of the exact weight function. The averaging procedure for the kinetic functional (averaging the Fermi momentum of the electron gas, instead of averaging the electron density) leads to a functional without numerical difficulties in the calculation of extended systems, and it gives excellent results when applied to atoms and jellium surfaces. copyright 1996 The American Physical Society

  15. Graphene plasmons: Impurities and nonlocal effects

    Science.gov (United States)

    Viola, Giovanni; Wenger, Tobias; Kinaret, Jari; Fogelström, Mikael

    2018-02-01

    This work analyzes how impurities and vacancies on the surface of a graphene sample affect its optical conductivity and plasmon excitations. The disorder is analyzed in the self-consistent Green's function formulation and nonlocal effects are fully taken into account. It is shown that impurities modify the linear spectrum and give rise to an impurity band whose position and width depend on the two parameters of our model, the density and the strength of impurities. The presence of the impurity band strongly influences the electromagnetic response and the plasmon losses. Furthermore, we discuss how the impurity-band position can be obtained experimentally from the plasmon dispersion relation and discuss this in the context of sensing.

  16. The quantum handshake entanglement, nonlocality and transactions

    CERN Document Server

    Cramer, John G

    2016-01-01

    This book shines bright light into the dim recesses of quantum theory, where the mysteries of entanglement, nonlocality, and wave collapse have motivated some to conjure up multiple universes, and others to adopt a "shut up and calculate" mentality. After an extensive and accessible introduction to quantum mechanics and its history, the author turns attention to his transactional model. Using a quantum handshake between normal and time-reversed waves, this model provides a clear visual picture explaining the baffling experimental results that flow daily from the quantum physics laboratories of the world. To demonstrate its powerful simplicity, the transactional model is applied to a collection of counter-intuitive experiments and conceptual problems.

  17. Certainty relations between local and nonlocal observables

    International Nuclear Information System (INIS)

    Diaz, R Garcia; Romero, J L; Bjoerk, G; Bourennane, M

    2005-01-01

    We point out that for an arbitrary number of identical particles, each defined on a Hilbert space of arbitrary dimension, there exists a whole ladder of relations of complementarity between certain local and nonlocal measurements corresponding to every conceivable grouping of the particles, e.g., the more accurately we can know (by a measurement) some joint property of three qubits (projecting the state onto a tripartite-entangled state), the less accurate some other property, local to the three qubits, becomes. We investigate the relation between these complementarity relations and a similar relation based on interference visibilities. We also show that the complementarity relations are particularly tight for particles defined on prime dimensional Hilbert spaces

  18. Music enjoyment with cochlear implantation.

    Science.gov (United States)

    Prevoteau, Charlotte; Chen, Stephanie Y; Lalwani, Anil K

    2018-03-05

    Since the advent of cochlear implant (CI) surgery in the 1960s, there have been remarkable technological and surgical advances enabling excellent speech perception in quiet with many CI users able to use the telephone. However, many CI users struggle with music perception, particularly with the pitch-based and melodic elements of music. Yet remarkably, despite poor music perception, many CI users enjoy listening to music based on self-report questionnaires, and prospective studies have suggested a disassociation between music perception and enjoyment. Music enjoyment is arguably a more functional measure of one's listening experience, and thus enhancing one's listening experience is a worthy goal. Recent studies have shown that re-engineering music to reduce its complexity may enhance enjoyment in CI users and also delineate differences in musical preferences from normal hearing listeners. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Unusual resonances in nanoplasmonic structures due to nonlocal response

    DEFF Research Database (Denmark)

    Raza, Søren; Toscano, Giuseppe; Jauho, Antti-Pekka

    2011-01-01

    We study the nonlocal response of a confined electron gas within the hydrodynamical Drude model. We address the question as to whether plasmonic nanostructures exhibit nonlocal resonances that have no counterpart in the local-response Drude model. Avoiding the usual quasistatic approximation, we...... find that such resonances do indeed occur, but only above the plasma frequency. Thus the recently found nonlocal resonances at optical frequencies for very small structures, obtained within quasistatic approximation, are unphysical. As a specific example we consider nanosized metallic cylinders...

  20. Degenerate-band-edge engineering inspired by nonlocal transformation optics

    Directory of Open Access Journals (Sweden)

    Moccia Massimo

    2016-01-01

    Full Text Available We address the engineering of degenerate-band-edge effects in nonlocal metamaterials. Our approach, inspired by nonlocal-transformation-optics concepts, is based on the approximation of analytically-derived nonlocal constitutive “blueprints”. We illustrate the synthesis procedure, and present and validate a possible implementation based on multilayered metamaterials featuring anisotropic constituents. We also elucidate the physical mechanisms underlying our approach and proposed configuration, and highlight the substantial differences with respect to other examples available in the topical literature.

  1. Risk of Bacterial Meningitis in Children with Cochlear Implants

    Science.gov (United States)

    ... Information For… Media Policy Makers Risk of Bacterial Meningitis in Children with Cochlear Implants Language: English (US) ... Compartir 2002 Study of the Risk of Bacterial Meningitis in Children with Cochlear Implants Many people have ...

  2. The group delay and suppression pattern of the cochlear microphonic potential recorded at the round window.

    Directory of Open Access Journals (Sweden)

    Wenxuan He

    Full Text Available BACKGROUND: It is commonly assumed that the cochlear microphonic potential (CM recorded from the round window (RW is generated at the cochlear base. Based on this assumption, the low-frequency RW CM has been measured for evaluating the integrity of mechanoelectrical transduction of outer hair cells at the cochlear base and for studying sound propagation inside the cochlea. However, the group delay and the origin of the low-frequency RW CM have not been demonstrated experimentally. METHODOLOGY/PRINCIPAL FINDINGS: This study quantified the intra-cochlear group delay of the RW CM by measuring RW CM and vibrations at the stapes and basilar membrane in gerbils. At low sound levels, the RW CM showed a significant group delay and a nonlinear growth at frequencies below 2 kHz. However, at high sound levels or at frequencies above 2 kHz, the RW CM magnitude increased proportionally with sound pressure, and the CM phase in respect to the stapes showed no significant group delay. After the local application of tetrodotoxin the RW CM below 2 kHz became linear and showed a negligible group delay. In contrast to RW CM phase, the BM vibration measured at location ∼2.5 mm from the base showed high sensitivity, sharp tuning, and nonlinearity with a frequency-dependent group delay. At low or intermediate sound levels, low-frequency RW CMs were suppressed by an additional tone near the probe-tone frequency while, at high sound levels, they were partially suppressed only at high frequencies. CONCLUSIONS/SIGNIFICANCE: We conclude that the group delay of the RW CM provides no temporal information on the wave propagation inside the cochlea, and that significant group delay of low-frequency CMs results from the auditory nerve neurophonic potential. Suppression data demonstrate that the generation site of the low-frequency RW CM shifts from apex to base as the probe-tone level increases.

  3. Modulational instability in the nonlocal chi(2)-model

    DEFF Research Database (Denmark)

    Wyller, John Andreas; Krolikowski, Wieslaw; Bang, Ole

    2007-01-01

    We investigate in detail the linear regime of the modulational instability (MI) properties of the plane waves of the nonlocal model for chi((2))- media formulated in Nikolov et al. [N.I. Nikolov, D. Neshev, O. Bang, W.Z. Krolikowski, Quadratic solitons as nonlocal solitons, Phys. Rev. E 68 (2003...... in the parameter space for which a fundamental gain band exists, and regions for which higher order gain bands and modulational stability exist. We also show that the MI analysis for the nonlocal model is applicable in the finite walk-off case. Finally, we show that the plane waves of the nonlocal chi((2))-model...... are recovered as the asymptotic limit of one of the branches of the plane waves (i.e. the adiabatic branch or the acoustic branch) of the full chi((2))-model by means of a singular perturbational approach. It is also proven that the stability results for the adiabatic branch continuously approach those...

  4. Size-dependent nonlocal effects in plasmonic semiconductor particles

    DEFF Research Database (Denmark)

    Maack, Johan Rosenkrantz; Mortensen, N. Asger; Wubs, Martijn

    2017-01-01

    Localized surface plasmons (LSP) in semiconductor particles are expected to exhibit spatial nonlocal response effects as the geometry enters the nanometer scale. To investigate these nonlocal effects, we apply the hydrodynamic model to nanospheres of two different semiconductor materials: intrinsic...... InSb and n-doped GaAs. Our results show that the semiconductors indeed display nonlocal effects, and that these effects are even more pronounced than in metals. In a 150 nm InSb particle at 300 K, the LSP frequency is blueshifted 35%, which is orders of magnitude larger than the blueshift in a metal...... particle of the same size. This property, together with their tunability, makes semiconductors a promising platform for experiments in nonlocal effects. Copyright (C)EPLA, 2017...

  5. Coupling of nonlocal and local continuum models by the Arlequinapproach

    KAUST Repository

    Han, Fei

    2011-08-09

    The objective of this work is to develop and apply the Arlequin framework to couple nonlocal and local continuum mechanical models. A mechanically-based model of nonlocal elasticity, which involves both contact and long-range forces, is used for the \\'fine scale\\' description in which nonlocal interactions are considered to have non-negligible effects. Classical continuum mechanics only involving local contact forces is introduced for the rest of the structure where these nonlocal effects can be neglected. Both models overlap in a coupling subdomain called the \\'gluing area\\' in which the total energy is separated into nonlocal and local contributions by complementary weight functions. A weak compatibility is ensured between kinematics of both models using Lagrange multipliers over the gluing area. The discrete formulation of this specific Arlequin coupling framework is derived and fully described. The validity and limits of the technique are demonstrated through two-dimensional numerical applications and results are compared against those of the fully nonlocal elasticity method. © 2011 John Wiley & Sons, Ltd.

  6. Retrolabyrinthine approach for cochlear nerve preservation in neurofibromatosis type 2 and simultaneous cochlear implantation

    Directory of Open Access Journals (Sweden)

    Bento, Ricardo Ferreira

    2014-01-01

    Full Text Available Introduction: Few cases of cochlear implantation (CI in neurofibromatosis type 2 (NF2 patients had been reported in the literature. The approaches described were translabyrinthine, retrosigmoid or middle cranial fossa. Objectives: To describe a case of a NF2- deafened-patient who underwent to vestibular schwannoma resection via RLA with cochlear nerve preservation and CI through the round window, at the same surgical time. Resumed Report: A 36-year-old woman with severe bilateral hearing loss due to NF2 was submitted to vestibular schwannoma resection and simultaneous CI. Functional assessment of cochlear nerve was performed by electrical promontory stimulation. Complete tumor removal was accomplishment via RLA with anatomic and functional cochlear and facial nerve preservation. Cochlear electrode array was partially inserted via round window. Sound field hearing threshold improvement was achieved. Mean tonal threshold was 46.2 dB HL. The patient could only detect environmental sounds and human voice but cannot discriminate vowels, words nor do sentences at 2 years of follow-up. Conclusion: Cochlear implantation is a feasible auditory restoration option in NF2 when cochlear anatomic and functional nerve preservation is achieved. The RLA is adequate for this purpose and features as an option for hearing preservation in NF2 patients.

  7. Considering optogenetic stimulation for cochlear implants.

    Science.gov (United States)

    Jeschke, Marcus; Moser, Tobias

    2015-04-01

    Electrical cochlear implants are by far the most successful neuroprostheses and have been implanted in over 300,000 people worldwide. Cochlear implants enable open speech comprehension in most patients but are limited in providing music appreciation and speech understanding in noisy environments. This is generally considered to be due to low frequency resolution as a consequence of wide current spread from stimulation contacts. Accordingly, the number of independently usable stimulation channels is limited to less than a dozen. As light can be conveniently focused, optical stimulation might provide an alternative approach to cochlear implants with increased number of independent stimulation channels. Here, we focus on summarizing recent work on optogenetic stimulation as one way to develop optical cochlear implants. We conclude that proof of principle has been presented for optogenetic stimulation of the cochlea and central auditory neurons in rodents as well as for the technical realization of flexible μLED-based multichannel cochlear implants. Still, much remains to be done in order to advance the technique for auditory research and even more for eventual clinical translation. This article is part of a Special Issue entitled . Copyright © 2015. Published by Elsevier B.V.

  8. A non-local PDE model for population dynamics with state-selective delay: Local theory and global attractors

    Science.gov (United States)

    Rezounenko, Alexander V.; Wu, Jianhong

    2006-06-01

    We propose a non-local PDE model for the evolution of a single species population that involves delayed feedback, where the delay such as the maturation time in the delayed birth rate, is selective and the selection depends on the status of the system. This delay selection, in contrast with the usual state-dependent delay widely used in ordinary delay differential equation, ensures the Lipschitz continuity of the nonlinear functional in the classical phase space. We also develop the local theory, and the existence and upper semi-continuity of the global attractor with respect to parameters.

  9. PET reconstruction via nonlocal means induced prior.

    Science.gov (United States)

    Hou, Qingfeng; Huang, Jing; Bian, Zhaoying; Chen, Wufan; Ma, Jianhua

    2015-01-01

    The traditional Bayesian priors for maximum a posteriori (MAP) reconstruction methods usually incorporate local neighborhood interactions that penalize large deviations in parameter estimates for adjacent pixels; therefore, only local pixel differences are utilized. This limits their abilities of penalizing the image roughness. To achieve high-quality PET image reconstruction, this study investigates a MAP reconstruction strategy by incorporating a nonlocal means induced (NLMi) prior (NLMi-MAP) which enables utilizing global similarity information of image. The present NLMi prior approximates the derivative of Gibbs energy function by an NLM filtering process. Specially, the NLMi prior is obtained by subtracting the current image estimation from its NLM filtered version and feeding the residual error back to the reconstruction filter to yield the new image estimation. We tested the present NLMi-MAP method with simulated and real PET datasets. Comparison studies with conventional filtered backprojection (FBP) and a few iterative reconstruction methods clearly demonstrate that the present NLMi-MAP method performs better in lowering noise, preserving image edge and in higher signal to noise ratio (SNR). Extensive experimental results show that the NLMi-MAP method outperforms the existing methods in terms of cross profile, noise reduction, SNR, root mean square error (RMSE) and correlation coefficient (CORR).

  10. Experimental nonlocal steering of Bohmian trajectories.

    Science.gov (United States)

    Xiao, Ya; Kedem, Yaron; Xu, Jin-Shi; Li, Chuan-Feng; Guo, Guang-Can

    2017-06-26

    Interpretations of quantum mechanics (QM), or proposals for underlying theories, that attempt to present a definite realist picture, such as Bohmian mechanics, require strong non-local effects. Naively, these effects would violate causality and contradict special relativity. However if the theory agrees with QM the violation cannot be observed directly. Here, we demonstrate experimentally such an effect: we steer the velocity and trajectory of a Bohmian particle using a remote measurement. We use a pair of photons and entangle the spatial transverse position of one with the polarization of the other. The first photon is sent to a double-slit-like apparatus, where its trajectory is measured using the technique of Weak Measurements. The other photon is projected to a linear polarization state. The choice of polarization state, and the result, steer the first photon in the most intuitive sense of the word. The effect is indeed shown to be dramatic, while being easy to visualize. We discuss its strength and what are the conditions for it to occur.

  11. Understanding quantum interference in general nonlocality

    International Nuclear Information System (INIS)

    Wang Haijun

    2011-01-01

    In this paper we attempt to give a new understanding of quantum double-slit interference of fermions in the framework of general nonlocality (GN) [J. Math. Phys. 49, 033513 (2008)] by studying the self-(inter)action of matter wave. From the metric of the GN, we derive a special formalism to interpret the interference contrast when the self-action is perturbative. According to the formalism, the characteristic of interference pattern is in agreement with experiment qualitatively. As examples, we apply the formalism to the cases governed by Schroedinger current and Dirac current, respectively, both of which are relevant to topology. The gap between these two cases corresponds to the fermion magnetic moment, which is possible to test in the near future. In addition, a general interference formalism for both perturbative and nonperturbative self-actions is presented. By analyzing the general formalism we predict that in the nonperturbative limit there is no interference at all. And by comparison with the special formalism of Schroedinger current, the coupling strength of self-action in the limit is found to be ∞. In the perturbative case, the interference from self-action turns out to be the same as that from the standard approach of quantum theory. Then comparing the corresponding coefficients quantitatively we conclude that the coupling strength of self-action in this case falls in the interval [0, 1].

  12. Exploring nonlocal observables in shock wave collisions

    Energy Technology Data Exchange (ETDEWEB)

    Ecker, Christian; Grumiller, Daniel; Stanzer, Philipp; Stricker, Stefan A. [Institut für Theoretische Physik, Technische Universität Wien,Wiedner Hauptstrasse 8-10, A-1040 Vienna (Austria); Schee, Wilke van der [Center for Theoretical Physics, Massachusetts Institute of Technology,77 Massachusetts Avenue, Cambridge, MA 02139 (United States)

    2016-11-09

    We study the time evolution of 2-point functions and entanglement entropy in strongly anisotropic, inhomogeneous and time-dependent N=4 super Yang-Mills theory in the large N and large ’t Hooft coupling limit using AdS/CFT. On the gravity side this amounts to calculating the length of geodesics and area of extremal surfaces in the dynamical background of two colliding gravitational shockwaves, which we do numerically. We discriminate between three classes of initial conditions corresponding to wide, intermediate and narrow shocks, and show that they exhibit different phenomenology with respect to the nonlocal observables that we determine. Our results permit to use (holographic) entanglement entropy as an order parameter to distinguish between the two phases of the cross-over from the transparency to the full-stopping scenario in dynamical Yang-Mills plasma formation, which is frequently used as a toy model for heavy ion collisions. The time evolution of entanglement entropy allows to discern four regimes: highly efficient initial growth of entanglement, linear growth, (post) collisional drama and late time (polynomial) fall off. Surprisingly, we found that 2-point functions can be sensitive to the geometry inside the black hole apparent horizon, while we did not find such cases for the entanglement entropy.

  13. Cochlear implant after bacterial meningitis.

    Science.gov (United States)

    Bille, Jesper; Ovesen, Therese

    2014-06-01

    The aim of this retrospective case study at a tertiary referral center was to investigate the outcome of cochlear implantation (CI) in children with sensorineural hearing loss due to meningitis compared to CI in children with deafness due to other reasons. This post-meningial group (PMG) consisted of 22 children undergoing CI due to deafness induced by meningitis, between December 1996 and January 2012. Five children had bilateral simultaneous implantation. None was excluded and the children were followed for at least 3 years. Operations were carried out by one of two surgeons using similar techniques in all cases. Each patient from the PMG was matched 2:1 with children having implantation for other reasons according to age and follow up (control group). Overall, the median category of auditory performance (CAP) and speech intelligibility rating (SIR) score were not statistically significantly different between the two groups. The presence of additional central nervous system (CNS) disorders (post-meningeal sequelae), however, correlated significantly with poorer outcome CI was a safe procedure without surgical complications in the present study. It is possible to restore auditory capacity and speech performance to a degree comparable to children undergoing implantation for other reasons. A statistically important variable is secondary CNS involvement. The rehabilitation program after CI should be adjusted according to these additional handicaps. It is recommended to screen meningitis patients as fast as possible to identify those with hearing loss and initiate treatment with hearing aids or CI. © 2013 The Authors. Pediatrics International © 2013 Japan Pediatric Society.

  14. Racemic meroterpenoids from Ganoderma cochlear.

    Science.gov (United States)

    Peng, Xingrong; Wang, Xia; Chen, Long; Yang, Han; Li, Lei; Lu, Shuangyang; Zhou, Lin; Qiu, Minghua

    2018-03-11

    Ganoderma cochlear, as edible and medicinal fungus, has long been used to prevent and treat various diseases. As our continuously phytochemical investigation of this fungus, a HPLC-UV-guided method led to the isolation of nine previously undescribed aromatic meroterpenoids with different ring systems, including six pairs of racemates, (±)-cochlearins A-E, G (1-5, 7), and three new analogues, cochlearins F, H and I (6, 8, 9). Their structures were elucidated by extensive 1D, 2D NMR spectroscopic data and MS analyses. The stereostructures of (±)-cochlearins A and B (1 and 2) were assigned using electronic circular dichroism (ECD) calculations. All of the isolates showed comparable antioxidant activities with IC 50 values of 3.1 ± 0.1-5.3 ± 0.1 μM, compared to the positive control (trolox, IC 50 : 3.3 ± 0.1 μM). (±)-Cochlearin D (4) and (+)-4 exhibited weak inhibitory effects for the proliferation of hepatic stellate cells (HSCs) induced by transforming growth factor-β1 (TGF-β1). Copyright © 2018. Published by Elsevier B.V.

  15. Musical experience sharpens human cochlear tuning.

    Science.gov (United States)

    Bidelman, Gavin M; Nelms, Caitlin; Bhagat, Shaum P

    2016-05-01

    The mammalian cochlea functions as a filter bank that performs a spectral, Fourier-like decomposition on the acoustic signal. While tuning can be compromised (e.g., broadened with hearing impairment), whether or not human cochlear frequency resolution can be sharpened through experiential factors (e.g., training or learning) has not yet been established. Previous studies have demonstrated sharper psychophysical tuning curves in trained musicians compared to nonmusicians, implying superior peripheral tuning. However, these findings are based on perceptual masking paradigms, and reflect engagement of the entire auditory system rather than cochlear tuning, per se. Here, by directly mapping physiological tuning curves from stimulus frequency otoacoustic emissions (SFOAEs)-cochlear emitted sounds-we show that estimates of human cochlear tuning in a high-frequency cochlear region (4 kHz) is further sharpened (by a factor of 1.5×) in musicians and improves with the number of years of their auditory training. These findings were corroborated by measurements of psychophysical tuning curves (PTCs) derived via simultaneous masking, which similarly showed sharper tuning in musicians. Comparisons between SFOAE and PTCs revealed closer correspondence between physiological and behavioral curves in musicians, indicating that tuning is also more consistent between different levels of auditory processing in trained ears. Our findings demonstrate an experience-dependent enhancement in the resolving power of the cochlear sensory epithelium and the spectral resolution of human hearing and provide a peripheral account for the auditory perceptual benefits observed in musicians. Both local and feedback (e.g., medial olivocochlear efferent) mechanisms are discussed as potential mechanisms for experience-dependent tuning. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Nonlocal interaction of inverse magnetic energy transfer in hall magnetohydrodynamic turbulence

    International Nuclear Information System (INIS)

    Araki, Keisuke; Miura, Hideaki

    2011-01-01

    A detailed analysis of forward and inverse energy transfer processes due to the Hall term effect in freely decaying, homogeneous, isotropic Hall magnetohydrodynamics (HMHD) turbulence is performed through Fourier and wavelet analyses. We analyzed three snapshot datasets that were taken from such a period to allow the turbulence to develop sufficiently with a nearly constant magnetic Reynolds number. Because the Fourier energy spectra in these snapshots show remarkable agreement after the normalization in terms of the dissipation rates and the diffusion coefficients, they are considered as a universal equilibrium state. By analyzing the numerical solutions that are generated without any external forcing, it is confirmed that the inverse energy transfer due to the Hall term effect is intrinsic to HMHD dynamics. Orthonormal divergence-free wavelet analysis reveals that nonlinear mode interactions contributing to the inverse energy transfer exhibit a nonlocal feature, while those for the forward transfer are dominated by a local feature. (author)

  17. Stability of stationary states of non-local equations with singular interaction potentials

    KAUST Repository

    Fellner, Klemens

    2011-04-01

    We study the large-time behaviour of a non-local evolution equation for the density of particles or individuals subject to an external and an interaction potential. In particular, we consider interaction potentials which are singular in the sense that their first derivative is discontinuous at the origin.For locally attractive singular interaction potentials we prove under a linear stability condition local non-linear stability of stationary states consisting of a finite sum of Dirac masses. For singular repulsive interaction potentials we show the stability of stationary states of uniformly bounded solutions under a convexity condition.Finally, we present numerical simulations to illustrate our results. © 2010 Elsevier Ltd.

  18. Partial differential variational inequalities involving nonlocal boundary conditions in Banach spaces

    Science.gov (United States)

    Liu, Zhenhai; Migórski, Stanisław; Zeng, Shengda

    2017-10-01

    In this paper, we firstly introduce a complicated system obtained by mixing a nonlinear evolutionary partial differential equation and a mixed variational inequality in infinite dimensional Banach spaces in the case where the set of constraints is not necessarily bounded and the problem is driven by nonlocal boundary conditions, which is called partial differential variational inequality ((PDVI), for short). Then, we show that the solution set of the mixed variational inequality involved in problem (PDVI) is nonempty, bounded, closed and convex. Moreover, the upper semicontinuity and measurability properties for set-valued mapping U : [ 0 , T ] ×E2 → Cbv (E1) (see (3.7), below) are also established. Finally, several existence results for (PDVI) are obtained by using a fixed point theorem for condensing set-valued operators and theory of measure of noncompactness.

  19. Monostable traveling waves for a time-periodic and delayed nonlocal reaction-diffusion equation

    Science.gov (United States)

    Li, Panxiao; Wu, Shi-Liang

    2018-04-01

    This paper is concerned with a time-periodic and delayed nonlocal reaction-diffusion population model with monostable nonlinearity. Under quasi-monotone or non-quasi-monotone assumptions, it is known that there exists a critical wave speed c_*>0 such that a periodic traveling wave exists if and only if the wave speed is above c_*. In this paper, we first prove the uniqueness of non-critical periodic traveling waves regardless of whether the model is quasi-monotone or not. Further, in the quasi-monotone case, we establish the exponential stability of non-critical periodic traveling fronts. Finally, we illustrate the main results by discussing two types of death and birth functions arising from population biology.

  20. Nonlinear optics

    CERN Document Server

    Bloembergen, Nicolaas

    1996-01-01

    Nicolaas Bloembergen, recipient of the Nobel Prize for Physics (1981), wrote Nonlinear Optics in 1964, when the field of nonlinear optics was only three years old. The available literature has since grown by at least three orders of magnitude.The vitality of Nonlinear Optics is evident from the still-growing number of scientists and engineers engaged in the study of new nonlinear phenomena and in the development of new nonlinear devices in the field of opto-electronics. This monograph should be helpful in providing a historical introduction and a general background of basic ideas both for expe

  1. Follow-up of cochlear implant use in patients who developed bacterial meningitis following cochlear implantation.

    Science.gov (United States)

    Mancini, Patrizia; D'Elia, Chiara; Bosco, Ersilia; De Seta, Elio; Panebianco, Valeria; Vergari, Valeria; Filipo, Roberto

    2008-08-01

    The present study is a long-term follow-up of speech perception outcomes and cochlear implant use in three cases of meningitis that occurred after cochlear implantation. Case series study. Study was performed on three children implanted with different models of Clarion devices, two of them with positioner. Recognition and comprehension were assessed via the Italian adaptation of GASP (TAP) test, and phonetically balanced bi-syllabic words in open-set. High resolution computed tomography scan acquisition was performed to obtain axial coronal and oblique multiplanar reconstructions of the cochlea. Two patients were affected by enlarged cochlear acqueduct and Mondini malformation the first carrying positioner. One patient had a normal cochlea, and the positioner could have been the main cause of bacterial spread. As a consequence of meningitis the child with normal cochlea and the other with enlarged vestibular acqueduct developed cochlear ossification, increased M-level and worsening of hearing outcomes. The child with Mondini malformation developed facial nerve stimulation. Contralateral implantation was performed in the first two patients. Bacterial meningitis occurring after cochlear implantation may induce cochlear ossification, facial nerve stimulation, and permanent or temporary loss of implant use. Planned follow-up with high resolution computed tomography and evaluation of M-levels could be useful prognostic tools in the management of these patients.

  2. Nonlinear and stochastic dynamics of coherent structures

    DEFF Research Database (Denmark)

    Rasmussen, Kim

    1997-01-01

    considered in the discrete model. Finally, nonlinear Schrödinger continuum and discrete models with nonlocal d ispersion are investigated. In the introductory chapter the physical situation of energy transport on molecular aggregates in which the results applies is discussed in detail. This chapter also...... introduces the nonlinear Schrödinger model in one and two dimensions, discussing the soliton solutions in one dimension and the collapse phenomenon in two dimensions. Also various analytical methods are described. Then a derivation of the nonlinear Schrödinger equation is given, based on a Davydov like...... phenomenon. We find numerically and analytically that the collapse can be delayed and ultimatively arrested by the fluctuations. Allowing the system to reach thermal equilibrium we further augment the model by a nonlineardamping term and find that this prohibits collapse in the strict mathematical se nse...

  3. Maximum nonlocality in the (3,2,2) scenario

    Science.gov (United States)

    López-Rosa, Sheila; Xu, Zhen-Peng; Cabello, Adán

    2016-12-01

    We identify the simplest combinations of entanglement and incompatibility giving the maximum quantum violation for each of the 46 classes of tight Bell inequalities for the (3,2,2) scenario, i.e., three parties, two measurements per party, and two outcomes per measurement. This allows us to classify the maximum quantum nonlocality according to the simplest resources needed to achieve it. We show that entanglement and incompatibility only produce maximum nonlocality when they are combined in specific ways. For each entanglement class there is, in most cases, just one incompatibility class leading to maximum nonlocality. We also identify two interesting cases. We show that the maximum quantum violation of Śliwa inequality 23 only occurs when the third party measures the identity, so nonlocality cannot increase when we add a third party to the bipartite case. Almost quantum correlations predict that adding a new party increases nonlocality. This points out that either almost quantum correlations violate a fundamental principle or that there is a form of tripartite entanglement which quantum theory cannot account for. The other interesting case is the maximum quantum violation of Śliwa inequality 26, which, like the Mermin inequality, requires maximum incompatibility for all parties. In contrast, it requires a specific entangled state which has the same tripartite negativity as the W state.

  4. Nonlocal non-Markovian effects in dephasing environments

    International Nuclear Information System (INIS)

    Xie Dong; Wang An-Min

    2014-01-01

    We study the nonlocal non-Markovian effects through local interactions between two subsystems and the corresponding two environments. It has been found that the initial correlations between two environments can turn a Markovian to a non-Markovian regime with extra control on the local interaction time. We further research the nonlocal non-Markovian effects from two situations: without extra control, the nonlocal non-Markovian effects only appear under the condition that two local dynamics are non-Markovian–non-Markovian (both of the two local dynamics are non-Markovian) or Markovian–non-Markovian, but not under the condition of Markovian–Markovian; with extra control, the nonlocal non-Markovian effects can occur under the condition of Markovian–Markovian. It shows that the function of correlations between two environments has an upper bound, which makes a flow of information from the environment back to the global system beginning finitely earlier than that back to one of the two local systems, not infinitely. Then, we proposed two special ways to distribute classical correlations between two environments without initial correlations. Finally, from numerical solutions in the spin star configuration, we found that the self-correlation (internal correlation) of each environment promotes the nonlocal non-Markovian effects. (general)

  5. Evidence of Non-local Chemical, Thermal and Gravitational Effects

    Directory of Open Access Journals (Sweden)

    Hu H.

    2007-04-01

    Full Text Available Quantum entanglement is ubiquitous in the microscopic world and manifests itself macroscopically under some circumstances. But common belief is that it alone cannot be used to transmit information nor could it be used to produce macroscopic non- local effects. Yet we have recently found evidence of non-local effects of chemical substances on the brain produced through it. While our reported results are under independent verifications by other groups, we report here our experimental findings of non-local chemical, thermal and gravitational effects in simple physical systems such as reservoirs of water quantum-entangled with water being manipulated in a remote reservoir. With the aids of high-precision instruments, we have found that the pH value, temperature and gravity of water in the detecting reservoirs can be non-locally affected through manipulating water in the remote reservoir. In particular, the pH value changes in the same direction as that being manipulated; the temperature can change against that of local environment; and the gravity apparently can also change against local gravity. These non-local effects are all reproducible and can be used for non-local signalling and many other purposes. We suggest that they are mediated by quantum entanglement between nuclear and/or electron spins in treated water and discuss the implications of these results.

  6. Nonlocal conductivity in type-II superconductors

    International Nuclear Information System (INIS)

    Mou, C.; Wortis, R.; Dorsey, A.T.; Huse, D.A.

    1995-01-01

    Multiterminal transport measurements on YBa 2 Cu 2 O 7 crystals in the vortex liquid regime have shown nonlocal conductivity on length scales up to 50 microns. Motivated by these results we explore the wave vector (k) dependence of the dc conductivity tensor, σ μν (k), in the Meissner, vortex lattice, and disordered phases of a type-II superconductor. Our results are based on time-dependent Ginzburg-Landau (TDGL) theory and on phenomenological arguments. We find four qualitatively different types of behavior. First, in the Meissner phase, the conductivity is infinite at k=0 and is a continuous function of k, monotonically decreasing with increasing k. Second, in the vortex-lattice phase, in the absence of pinning, the conductivity is finite (due to flux flow) at k=0; it is discontinuous there and remains qualitatively like the Meissner phase for k>0. Third, in the vortex liquid regime in a magnetic field and at low temperature, the conductivity is finite, smooth and nonmonotonic, first increasing with k at small k and then decreasing at larger k. This third behavior is expected to apply at temperatures just above the melting transition of the vortex lattice, where the vortex liquid shows strong short-range order and a large viscosity. Finally, at higher temperatures in the disordered phase, the conductivity is finite, smooth and again monotonically decreasing with k. This last, monotonic behavior applies in zero magnetic field for the entire disordered phase, i.e., at all temperatures above T c , while in a field the nonmonotonic behavior may occur in a low-temperature portion of the disordered phase

  7. Estimation of stimulus attenuation in cochlear implants

    CSIR Research Space (South Africa)

    Smit, Jacoba E

    2009-03-01

    Full Text Available in cochlear stimulation. Ann N Y Acad Sci, 1983; 405: 137-45. 30 Blight AR. Computer simulation of action potentials and afterpotentials in mammalian myelinated axons: The case for a lower resistance myelin sheath. Neuroscience, 1985; 15: 13- 31...

  8. Auditory Learning in Children with Cochlear Implants

    Science.gov (United States)

    Mishra, Srikanta K.; Boddupally, Shiva P.; Rayapati, Deeksha

    2015-01-01

    Purpose: The purpose of this study was to examine and characterize the training-induced changes in speech-in-noise perception in children with congenital deafness who have cochlear implants (CIs). Method: Twenty-seven children with congenital deafness who have CIs were studied. Eleven children with CIs were trained on a speech-in-noise task,…

  9. Cochlear implant candidates with psychogenic hearing loss.

    Science.gov (United States)

    Kompis, Martin; Senn, Pascal; Mantokoudis, Georgios; Caversaccio, Marco

    2015-04-01

    Specific requests for cochlear implantations by persons with psychogenic hearing loss are a relatively new phenomenon. A number of features seems to be over-represented in this group of patients. The existence of these requests stresses the importance of auditory brainstem response (ABR) measurements before cochlear implantation. To describe the phenomenon of patients with psychogenic hearing losses specifically requesting cochlear implantation, and to gain first insights into the characteristics of this group. Analysis of all cases seen between 2004 and 2013 at the University Hospital of Bern, Switzerland. Four cochlear implant candidates with psychogenic hearing loss were identified. All were female, aged 23-51 years. Hearing thresholds ranged from 86 dB to 112 dB HL (pure-tone average 500-4000 Hz). ABRs and otoacoustic emissions (OAEs) showed bilaterally normal hearing in two subjects, and hearing thresholds between 30 and 50 dB in the other two subjects. Three subjects suffered from depression and one from a pathologic fear of cancer. Three had a history of five or more previous surgeries. Three were smokers and three reported other close family members with hearing losses. All four were hearing aid users at the time of presentation.

  10. Simplifying cochlear implant speech processor fitting

    NARCIS (Netherlands)

    Willeboer, C.

    2008-01-01

    Conventional fittings of the speech processor of a cochlear implant (CI) rely to a large extent on the implant recipient's subjective responses. For each of the 22 intracochlear electrodes the recipient has to indicate the threshold level (T-level) and comfortable loudness level (C-level) while

  11. Environmental Sound Training in Cochlear Implant Users

    Science.gov (United States)

    Shafiro, Valeriy; Sheft, Stanley; Kuvadia, Sejal; Gygi, Brian

    2015-01-01

    Purpose: The study investigated the effect of a short computer-based environmental sound training regimen on the perception of environmental sounds and speech in experienced cochlear implant (CI) patients. Method: Fourteen CI patients with the average of 5 years of CI experience participated. The protocol consisted of 2 pretests, 1 week apart,…

  12. Listening Effort With Cochlear Implant Simulations

    NARCIS (Netherlands)

    Pals, Carina; Sarampalis, Anastasios; Başkent, Deniz

    2013-01-01

    Purpose: Fitting a cochlear implant (CI) for optimal speech perception does not necessarily optimize listening effort. This study aimed to show that listening effort may change between CI processing conditions for which speech intelligibility remains constant. Method: Nineteen normal-hearing

  13. The preoperative imaging evaluation for cochlear implantation

    International Nuclear Information System (INIS)

    Liu Zhonglin; Wang Zhenchang; Fu Lin; Li Yong; Xian Junfang; Yang Bentao; Lan Baosen; Li Yongxin; Zheng Jun; Song Yan; Liu Bo; Chen Xueqing; He Haili

    2006-01-01

    Objective: To analyze CT and MRI findings of temporal bone and to evaluate preoperative diagnostic value for cochlear implantation. Methods: One hundred and sixty candidates for cochlear implantation were examined with axial CT scan, 64 of them also with coronal CT scan, and 119 patients with MRI. Results: All of 320 ears were well-aerated, and 206 ears had mastoid cavities extended posteriorly to the sigmoid sinus. The length from posterior-lateral tympanic wall to the outer cortex was (2.34±0.42) mm (left side) and (2.25±0.40) mm (right side) (U=1.887, P 1 and T 2 signal on MRI. The congenital malformations of inner ear occurred in 67 ears, including complete dysplasia in 1 ear, cochlear hypodysplasia in 6 ears, Mondini deformation in 5 ears, enlarged vestibular aqueduct in 40 ears, dysplastic semicircular canal and the vestibulae in 10 ears, and narrowing of internal auditory canal in 5 ears. Conclusion: Preoperative imaging examinations can provide critical information to ensure successful cochlear' implantation. (authors)

  14. Partial jamming and non-locality in dense granular flows

    Directory of Open Access Journals (Sweden)

    Kharel Prashidha

    2017-01-01

    Full Text Available Dense granular flows can exhibit non-local flow behaviours that cannot be predicted by local constitutive laws alone. Such behaviour is accompanied by the existence of diverging cooperativity length. Here we show that this length can be attributed to the development of transient clusters of jammed particles within the flow. By performing DEM simulation of dense granular flows, we directly measure the size of such clusters which scales with the inertial number with a power law. We then derive a general non-local relation based on kinematic compatibility for the existence of clusters in an arbitrary non-homogenous flow. The kinematic nature of this derivation suggests that non-locality should be expected in any material regardless of their local constitutive law, as long as transient clusters exist within the flow.

  15. Magneto-electro-elastic buckling analysis of nonlocal curved nanobeams

    Science.gov (United States)

    Ebrahimi, Farzad; Reza Barati, Mohammad

    2016-09-01

    In this work, a size-dependent curved beam model is developed to take into account the effects of nonlocal stresses on the buckling behavior of curved magneto-electro-elastic FG nanobeams for the first time. The governing differential equations are derived based on the principle of virtual work and Euler-Bernoulli beam theory. The power-law function is employed to describe the spatially graded magneto-electro-elastic properties. By extending the radius of the curved nanobeam to infinity, the results of straight nonlocal FG beams can be rendered. The effects of magnetic potential, electric voltage, opening angle, nonlocal parameter, power-law index and slenderness ratio on buckling loads of curved MEE-FG nanobeams are studied.

  16. Application of nonlocal plasma technology for controlling plasma conductivity

    Science.gov (United States)

    Yuan, Chengxun; Demidov, V. I.; Kudryavtsev, A. A.; Kurlyandskaya, I. P.; Rudakova, T. V.; Zhou, Z. X.

    2017-10-01

    A promising approach for better control of the plasma parameters involves the exploitation of peculiarities of plasmas with a nonlocal electron energy distribution. Nonlocal plasma technology (NLP-technology) is based on the effect of energetic electrons in the plasma volume. In this work, an experimental study of influence of the chemo-ionization processes on non-stationary plasma conductivity has been conducted. Due to energetic, supra-thermal electrons, which appear in the chemo-ionization reactions, the highly non-equilibrium and time dependent nonlocal electron energy distribution function is formed. In such a plasma thermal electrons always have positive conductivity (mobility), while supra-thermal, energetic electrons may have negative conductivity in heavy (argon, krypton and xenon) noble gases dependently on conditions. Experiments demonstrate that this effect may lead to the non-monotonic temporal behavior of plasma conductivity and may potentially create the negative electron mobility.

  17. One-loop effective potential in nonlocal supersymmetric theories

    Science.gov (United States)

    de Mello, E. R. Bezerra; Gama, F. S.; Nascimento, J. R.; Petrov, A. Yu.

    2017-01-01

    Within the superfield approach, we consider the nonlocal generalization of the Wess-Zumino model and calculate the one-loop low-energy contributions to the effective action. Four different nonlocal models are considered, among which only the first model does not reduce to the standard Wess-Zumino model when we take the parameter of nonlocality of the model, Λ , much greater than any energy scale; in addition, this model also depends on an extra parameter ξ . As to the other three models, the result looks like the renormalized effective potential for the usual Wess-Zumino model, where the normalization scale μ is replaced by the Λ . Moreover, the fourth model displays a divergence which can be eliminated through the appropriate wave function renormalization.

  18. Non-local quantal Noether identities and their applications

    International Nuclear Information System (INIS)

    Li Ziping

    2002-01-01

    Based on the phase-space generating functional for a system with a singular high-order Lagrangian, the quantal canonical Noether identities under the local and non-local transformation in phase space for such system have been derived. For a gauge-invariant system with a higher-order Lagrangian, the quantal Noether identities under the local and non-local transformation in configuration space have also been derived. it has been pointed out that in certain cases the quantal Noether identities may be converted to the conservation laws at the quantum level. This algorithm to derive the quantal conservation laws is significantly different from the first quantal Noether theorem. The applications to the non-Abelian CS theories with higher-order derivatives are given. The conserved quantities at the quantum level for some local and non-local transformation are found respectively

  19. Computational Nanofluidics: Nonlocal Transport And The Glass Transition

    International Nuclear Information System (INIS)

    Puscasu, R.M.

    2011-01-01

    The paper gives a review of recent advances in theory and simulation of nonlocal transport in nano flows. The aim is to show how to computationally model and simulate the nonlocal viscous transport in atomic and molecular fluids. The ultimate goal is to provide nanofluidics and other disciplines with methodologies capable to give exact descriptions of flow at the nano scale by using nonlocal constitutive relations which involve nonlocal transport kernels. Nano materials have properties that can be substantially different from those of the corresponding bulk phases. In particular, fluid flows in pores or channels of nano scale dimension can deviate strongly from macroscopic expectations. When such structures approach the size regime corresponding to molecular scaling lengths, new physical constraints are placed on the behavior of the fluid. These physical constraints induce regions of the fluid to exhibit new properties (e.g. vastly increased viscosity near the pore wall) and they may affect changes in thermodynamic properties and may also alter the chemical reactivity of species at the fluid solid interface. Consequently, many classical theories break down and are no longer valid at such small length and time scales. The development of models that go beyond classical (Navier-Stokes-Fourier) hydrodynamics would be very helpful for the prediction and understanding of flows in highly confined geometries (typically 1-100 nm). While such nano scale systems can be very difficult to probe experimentally, they can be easily approached in a very strict manner by molecular modelling, providing theory and simulation an opportunity for the discovery of new phenomena. We therefore review in this article the advances within the framework of generalized hydrodynamics and present the latest theoretical developments and modelling results that can ultimately lead to suitable predictive tools capable of accurate prediction of the key physical properties of fluids under nano

  20. Poisson-Fermi Formulation of Nonlocal Electrostatics in Electrolyte Solutions

    Directory of Open Access Journals (Sweden)

    Liu Jinn-Liang

    2017-10-01

    Full Text Available We present a nonlocal electrostatic formulation of nonuniform ions and water molecules with interstitial voids that uses a Fermi-like distribution to account for steric and correlation efects in electrolyte solutions. The formulation is based on the volume exclusion of hard spheres leading to a steric potential and Maxwell’s displacement field with Yukawa-type interactions resulting in a nonlocal electric potential. The classical Poisson-Boltzmann model fails to describe steric and correlation effects important in a variety of chemical and biological systems, especially in high field or large concentration conditions found in and near binding sites, ion channels, and electrodes. Steric effects and correlations are apparent when we compare nonlocal Poisson-Fermi results to Poisson-Boltzmann calculations in electric double layer and to experimental measurements on the selectivity of potassium channels for K+ over Na+.

  1. Non-local charges in local quantum field theory

    International Nuclear Information System (INIS)

    Buchholz, D.; Lopuszanski, J.T.; Rabsztyn, S.

    1985-05-01

    Non-local charges are studied in the general setting of local quantum field theory. It is shown, that these charges can be represented as polynomials in the incoming respectively outgoing fields with coefficients (kernels) which are subject to specific constraints. For the restricted class of models of a scalar, massive, self interacting particle in four dimensions, a more detailed analysis shows that all non-local charges of the generic type (genus 2) are products of generators of the Poincare group. This analysis, which is based on the macroscopic causality properties of the S-matrix, seems to indicate that less trivial examples of non-local charges can only exist in two dimensions. (orig.)

  2. Anomalous facial nerve canal with cochlear malformations.

    Science.gov (United States)

    Romo, L V; Curtin, H D

    2001-05-01

    Anteromedial "migration" of the first segment of the facial nerve canal has been previously identified in a patient with a non-Mondini-type cochlear malformation. In this study, several patients with the same facial nerve canal anomaly were reviewed to assess for the association and type of cochlear malformation. CT scans of the temporal bone of 15 patients with anteromedial migration of the first segment of the facial nerve canal were collected from routine departmental examinations. In seven patients, the anomalous course was bilateral, for a total of 22 cases. The migration was graded relative to normal as either mild/moderate or pronounced. The cochlea in each of these cases was examined for the presence and size of the basilar, second, and apical turns. The turns were either absent, small, normal, or enlarged. The CT scans of five patients with eight Mondini malformations were examined for comparison. The degree of the facial nerve migration was pronounced in nine cases and mild/moderate in 13. All 22 of these cases had associated cochlear abnormalities of the non-Mondini variety. These included common cavity anomalies with lack of definition between the cochlea and vestibule (five cases), cochleae with enlarged basilar turns and absent second or third turns (five cases), and cochleae with small or normal basilar turns with small or absent second or third turns (12 cases). None of the patients with Mondini-type cochlear malformations had anteromedial migration of the facial nerve canal. Anteromedial migration of the facial nerve canal occurs in association with some cochlear malformations. It did not occur in association with the Mondini malformations. A cochlea with a Mondini malformation, being similar in size to a normal cochlea, may physically prohibit such a deviation in course.

  3. To the non-local theory of cold nuclear fusion.

    Science.gov (United States)

    Alexeev, Boris V

    2014-10-01

    In this paper, we revisit the cold fusion (CF) phenomenon using the generalized Bolzmann kinetics theory which can represent the non-local physics of this CF phenomenon. This approach can identify the conditions when the CF can take place as the soliton creation under the influence of the intensive sound waves. The vast mathematical modelling leads to affirmation that all parts of soliton move with the same velocity and with the small internal change of the pressure. The zone of the high density is shaped on the soliton's front. It means that the regime of the 'acoustic CF' could be realized from the position of the non-local hydrodynamics.

  4. Quantum nonlocal effects on optical properties of spherical nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Moradi, Afshin, E-mail: a.moradi@kut.ac.ir [Department of Engineering Physics, Kermanshah University of Technology, Kermanshah, Iran and Department of Nano Sciences, Institute for Studies in Theoretical Physics and Mathematics (IPM), Tehran (Iran, Islamic Republic of)

    2015-02-15

    To study the scattering of electromagnetic radiation by a spherical metallic nanoparticle with quantum spatial dispersion, we develop the standard nonlocal Mie theory by allowing for the excitation of the quantum longitudinal plasmon modes. To describe the quantum nonlocal effects, we use the quantum longitudinal dielectric function of the system. As in the standard Mie theory, the electromagnetic fields are expanded in terms of spherical vector wavefunctions. Then, the usual Maxwell boundary conditions are imposed plus the appropriate additional boundary conditions. Examples of calculated extinction spectra are presented, and it is found that the frequencies of the subsidiary peaks, due to quantum bulk plasmon excitations exhibit strong dependence on the quantum spatial dispersion.

  5. Strong Local-Nonlocal Coupling for Integrated Fracture Modeling

    Energy Technology Data Exchange (ETDEWEB)

    Littlewood, David John [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Silling, Stewart A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Mitchell, John A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Seleson, Pablo D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bond, Stephen D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Parks, Michael L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Turner, Daniel Z. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Burnett, Damon J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Ostien, Jakob [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Gunzburger, Max [Florida State Univ., Tallahassee, FL (United States)

    2015-09-01

    Peridynamics, a nonlocal extension of continuum mechanics, is unique in its ability to capture pervasive material failure. Its use in the majority of system-level analyses carried out at Sandia, however, is severely limited, due in large part to computational expense and the challenge posed by the imposition of nonlocal boundary conditions. Combined analyses in which peridynamics is em- ployed only in regions susceptible to material failure are therefore highly desirable, yet available coupling strategies have remained severely limited. This report is a summary of the Laboratory Directed Research and Development (LDRD) project "Strong Local-Nonlocal Coupling for Inte- grated Fracture Modeling," completed within the Computing and Information Sciences (CIS) In- vestment Area at Sandia National Laboratories. A number of challenges inherent to coupling local and nonlocal models are addressed. A primary result is the extension of peridynamics to facilitate a variable nonlocal length scale. This approach, termed the peridynamic partial stress, can greatly reduce the mathematical incompatibility between local and nonlocal equations through reduction of the peridynamic horizon in the vicinity of a model interface. A second result is the formulation of a blending-based coupling approach that may be applied either as the primary coupling strategy, or in combination with the peridynamic partial stress. This blending-based approach is distinct from general blending methods, such as the Arlequin approach, in that it is specific to the coupling of peridynamics and classical continuum mechanics. Facilitating the coupling of peridynamics and classical continuum mechanics has also required innovations aimed directly at peridynamic models. Specifically, the properties of peridynamic constitutive models near domain boundaries and shortcomings in available discretization strategies have been addressed. The results are a class of position-aware peridynamic constitutive laws for

  6. Complementarity and nonlocality in two-qudit systems

    Science.gov (United States)

    Wang, Hai; Kumar, Asutosh; Wu, Junde

    2018-03-01

    Complementarity and nonlocality are two characteristic traits of quantum physics that distinguish it from classical physics. In this paper, for the two-qubit case, we see that the complementarity between global and local observables in Bell's experiment sets a decisive foundation for the nonlocality of composite systems. We use the Hilbert-Schmidt norm on the commutator of two observables to quantify complementarity between them. Based on the CHSH experiment, we define a measure of complementarity Md for the two-qubit case, and extend it to two-qudit systems. Furthermore, we obtain an upper bound on Md that scales linearly in the Hilbert space dimension of the qudit.

  7. Faithful test of nonlocal realism with entangled coherent states

    International Nuclear Information System (INIS)

    Lee, Chang-Woo; Jeong, Hyunseok; Paternostro, Mauro

    2011-01-01

    We investigate the violation of Leggett's inequality for nonlocal realism using entangled coherent states and various types of local measurements. We prove mathematically the relation between the violation of the Clauser-Horne-Shimony-Holt form of Bell's inequality and Leggett's one when tested by the same resources. For Leggett inequalities, we generalize the nonlocal realistic bound to systems in Hilbert spaces larger than bidimensional ones and introduce an optimization technique that allows one to achieve larger degrees of violation by adjusting the local measurement settings. Our work describes the steps that should be performed to produce a self-consistent generalization of Leggett's original arguments to continuous-variable states.

  8. [Morphologic feature and cochlear implant surgical approach for cochlear modiolus deficiency].

    Science.gov (United States)

    Zhang, Daoxing

    2014-09-01

    To review the classification of cochlear modiolus deficiency and decision on surgical approach for above case,in order to provide mastery for cochlear implant (CI) indication. Basing on temporal bone HRCT pre-operation, CI subjects with modiolus deficiency were defined as following groups: (1) deficiency caused by cochlear dysplasia (Mondini malformation); (2) deficiency caused by dysplasia of cochlear and vestibule (Common cavity malformation); (3) deficiency caused by absence of internal acoustic meatus fundus (IP-III malformation). Three types of surgical approach were utilized: type I, electrode array was introduced through facial recess, enlarged the round window, type II, opened the surface of chchlea, electrode array was introduced through facial recess, fenestration on posterior promontory and then inserted around lateral wall of inner-cochlear cavity. type III, electrode array was introduce through fenestration of lateral semicircular canal and then placed close to the bony wall of common cavity. One hundred and sixty-six cochlear modiolus deficiency cases were identified into 3 groups as following: 135 Mondini malformation cases into group a, 18 common cavity malformation cases into group b, and 13 IP-III malformation cases into group c. Surgical approach: type I were used in 136 cases (123 Mondini cases and 13 IP-III cases), while approach type II in 12 cases (12 Mondini cases), and approach type III in 18 cases (18 common cavity cases). Income post-operation of CI: For group a (Mondini malformation), post-activation mean hearing threshold in sound field was 65 dB, speech recognition score is 95% (single finals test) and 25% (signal initials test), while it was 80 dB, 60% and 0 for group b (Conmon cavity malformation), and it was 55 dB, 100% and 45% for group c (IP-III malformation). The income of speech recognition score for cochlear modiolus deficiency was relatively poor, group b was worst and group c was best, while group a moderate.

  9. Nonlinear Science

    CERN Document Server

    Yoshida, Zensho

    2010-01-01

    This book gives a general, basic understanding of the mathematical structure "nonlinearity" that lies in the depths of complex systems. Analyzing the heterogeneity that the prefix "non" represents with respect to notions such as the linear space, integrability and scale hierarchy, "nonlinear science" is explained as a challenge of deconstruction of the modern sciences. This book is not a technical guide to teach mathematical tools of nonlinear analysis, nor a zoology of so-called nonlinear phenomena. By critically analyzing the structure of linear theories, and cl

  10. Nonlinear oscillations

    CERN Document Server

    Nayfeh, Ali Hasan

    1995-01-01

    Nonlinear Oscillations is a self-contained and thorough treatment of the vigorous research that has occurred in nonlinear mechanics since 1970. The book begins with fundamental concepts and techniques of analysis and progresses through recent developments and provides an overview that abstracts and introduces main nonlinear phenomena. It treats systems having a single degree of freedom, introducing basic concepts and analytical methods, and extends concepts and methods to systems having degrees of freedom. Most of this material cannot be found in any other text. Nonlinear Oscillations uses sim

  11. A nonlocal potential form for s-wave α-α scattering

    International Nuclear Information System (INIS)

    Amos, K.; Bennett, M.T.

    1997-01-01

    Low energy s-wave α-α phase shifts that agree well with the measured set, have been extracted using a nonlocal interaction formed by folding (local real) nucleon -α particle interactions with density matrix elements of the (projectile) α particle. The resultant nonlocal s-wave α-α interaction is energy dependent and has a nonlocality range of about 2 fm

  12. Non-local Integrals and Derivatives on Fractal Sets with Applications

    Directory of Open Access Journals (Sweden)

    Golmankhaneh Alireza K.

    2016-01-01

    Full Text Available In this paper, we discuss non-local derivatives on fractal Cantor sets. The scaling properties are given for both local and non-local fractal derivatives. The local and non-local fractal differential equations are solved and compared. Related physical models are also suggested.

  13. Non-local Integrals and Derivatives on Fractal Sets with Applications

    OpenAIRE

    Golmankhaneh, Alireza K.; Baleanu, Dumitru

    2017-01-01

    In this paper, we discussed the non-local derivative on the fractal Cantor set. The scaling properties are given for both local and non-local fractal derivatives. The local and non-local fractal differential equations are solved and compared and related physical models are suggested.

  14. Null controllability of a nonlinear population dynamics problem

    OpenAIRE

    Traore, Oumar

    2006-01-01

    We establish a null controllability result for a nonlinear population dynamics model. In our model, the birth term is nonlocal and describes the recruitment process in newborn individuals population. Using a derivation of Leray-Schauder fixed point theorem and Carleman inequality for the adjoint system, we show that for all given initial density, there exists an internal control acting on a small open set of the domain and leading the population to extinction.

  15. Nonlinear evolution inclusions arising from phase change models

    Czech Academy of Sciences Publication Activity Database

    Colli, P.; Krejčí, Pavel; Rocca, E.; Sprekels, J.

    2007-01-01

    Roč. 57, č. 4 (2007), s. 1067-1098 ISSN 0011-4642 R&D Projects: GA ČR GA201/02/1058 Institutional research plan: CEZ:AV0Z10190503 Keywords : nonlinear and nonlocal evolution equations * Cahn-Hilliard type dynamics * phase transitions models Subject RIV: BA - General Mathematics Impact factor: 0.155, year: 2007 http://www.dml.cz/bitstream/handle/10338.dmlcz/128228/CzechMathJ_57-2007-4_2.pdf

  16. Formation of localized structures in bistable systems through nonlocal spatial coupling. II. The nonlocal Ginzburg-Landau equation.

    Science.gov (United States)

    Gelens, Lendert; Matías, Manuel A; Gomila, Damià; Dorissen, Tom; Colet, Pere

    2014-01-01

    We study the influence of a linear nonlocal spatial coupling on the interaction of fronts connecting two equivalent stable states in the prototypical 1-dimensional real Ginzburg-Landau equation. While for local coupling the fronts are always monotonic and therefore the dynamical behavior leads to coarsening and the annihilation of pairs of fronts, nonlocal terms can induce spatial oscillations in the front, allowing for the creation of localized structures, emerging from pinning between two fronts. We show this for three different nonlocal influence kernels. The first two, mod-exponential and Gaussian, are positive definite and decay exponentially or faster, while the third one, a Mexican-hat kernel, is not positive definite.

  17. Nonlinear continuous-wave optical propagation in nematic liquid crystals: Interplay between reorientational and thermal effects.

    Science.gov (United States)

    Alberucci, Alessandro; Laudyn, Urszula A; Piccardi, Armando; Kwasny, Michał; Klus, Bartlomiej; Karpierz, Mirosław A; Assanto, Gaetano

    2017-07-01

    We investigate nonlinear optical propagation of continuous-wave (CW) beams in bulk nematic liquid crystals. We thoroughly analyze the competing roles of reorientational and thermal nonlinearity with reference to self-focusing/defocusing and, eventually, the formation of nonlinear diffraction-free wavepackets, the so-called spatial optical solitons. To this extent we refer to dye-doped nematic liquid crystals in planar cells excited by a single CW beam in the highly nonlocal limit. To adjust the relative weight between the two nonlinear responses, we employ two distinct wavelengths, inside and outside the absorption band of the dye, respectively. Different concentrations of the dye are considered in order to enhance the thermal effect. The theoretical analysis is complemented by numerical simulations in the highly nonlocal approximation based on a semi-analytic approach. Theoretical results are finally compared to experimental results in the Nematic Liquid Crystals (NLC) 4-trans-4'-n-hexylcyclohexylisothiocyanatobenzene (6CHBT) doped with Sudan Blue dye.

  18. Existence of solutions for nonlinear mixed type integrodifferential equation of second order

    Directory of Open Access Journals (Sweden)

    Haribhau Laxman Tidke

    2010-04-01

    Full Text Available In this paper, we investigate the existence of solutions for nonlinear mixed Volterra-Fredholm integrodifferential equation of second order with nonlocal conditions in Banach spaces. Our analysis is based on Leray-Schauder alternative, rely on a priori bounds of solutions and the inequality established by B. G. Pachpatte.

  19. Investigations of prosody perception by adult cochlear implant recipients

    DEFF Research Database (Denmark)

    Morris, David Jackson

    -synthesized speech to investigate the perceptual abilities of adult cochlear implant listeners in Danish and Swedish language settings. These studies examine performance relationships between prosody and other indexes of speech perception, including common clinical measurements.Results shed light on inherent device...... limitations and speech perception via an electrical-neural interface. This thesis is relevant to auditory rehabilitation, cochlear implant candidacy issues and sound processing in cochlear implants....

  20. A Literature Analysis of Themes in Paediatric Cochlear Implant Research

    DEFF Research Database (Denmark)

    Hendar, Nils Ola Ebbe; Dammeyer, Jesper Herup

    2015-01-01

    Research on children with cochlear implants (CI) has documented positive outcomes, but also that many still experience language delays. The aim of this article is to explore how research on children with cochlear implants cover topics of early language development compared to research on children...... and pragmatic) in research on children with cochlear implants compared to research in children with typical hearing. A need for more research with focus on pre-lingual themes in language acquisition is discussed....

  1. What Does Music Sound Like for a Cochlear Implant User?

    Science.gov (United States)

    Jiam, Nicole T; Caldwell, Meredith T; Limb, Charles J

    2017-09-01

    Cochlear implant research and product development over the past 40 years have been heavily focused on speech comprehension with little emphasis on music listening and enjoyment. The relatively little understanding of how music sounds in a cochlear implant user stands in stark contrast to the overall degree of importance the public places on music and quality of life. The purpose of this article is to describe what music sounds like to cochlear implant users, using a combination of existing research studies and listener descriptions. We examined the published literature on music perception in cochlear implant users, particularly postlingual cochlear implant users, with an emphasis on the primary elements of music and recorded music. Additionally, we administered an informal survey to cochlear implant users to gather first-hand descriptions of music listening experience and satisfaction from the cochlear implant population. Limitations in cochlear implant technology lead to a music listening experience that is significantly distorted compared with that of normal hearing listeners. On the basis of many studies and sources, we describe how music is frequently perceived as out-of-tune, dissonant, indistinct, emotionless, and weak in bass frequencies, especially for postlingual cochlear implant users-which may in part explain why music enjoyment and participation levels are lower after implantation. Additionally, cochlear implant users report difficulty in specific musical contexts based on factors including but not limited to genre, presence of lyrics, timbres (woodwinds, brass, instrument families), and complexity of the perceived music. Future research and cochlear implant development should target these areas as parameters for improvement in cochlear implant-mediated music perception.

  2. Electro-thermal vibration of a smart coupled nanobeam system with an internal flow based on nonlocal elasticity theory

    Energy Technology Data Exchange (ETDEWEB)

    Atabakhshian, V.; Shooshtari, A.; Karimi, M., E-mail: karimi_mh@yahoo.com

    2015-01-01

    In this study, nonlinear vibration and stability of a fluid-conveying nanotube (FCNT), elastically coupled to a smart piezoelectric polymeric beam (PPB) is investigated based on nonlocal elasticity theory, Euler–Bernoulli beam model and energy approach. In order to obtain an active instability control of FCNT, the PPB is longitudinally polarized as an actuator while in the absence of an imposed electric field it is also possible to be used as an alarm biosensor. Simulating the above smart coupled nanobeam system alike the double nanobeam systems (which are relatively developed by other authors) leads to obtain nonlinear differential equations of motion. The linear natural and damping frequencies are achieved by ignoring all the system nonlinearities which are then considered to obtain nonlinear frequencies using an iterative method. The effects of geometric nonlinearity, small scale parameter, coupled medium constants, Knudsen number, temperature change, aspect ratio and external applied voltage on critical flow velocity are studied in details. It is concluded that applying an electric voltage on PPB will increase the stability of FCNT. It is hoped that this research will provide a new approach to smart instability control of FCNTs which is no yet reported.

  3. Ermakov's Superintegrable Toy and Nonlocal Symmetries

    OpenAIRE

    Leach, P. G. L.; Karasu, A.; Nucci, M. C.; Andriopoulos, K.

    2005-01-01

    We investigate the symmetry properties of a pair of Ermakov equations. The system is superintegrable and yet possesses only three Lie point symmetries with the algebra sl(2, R). The number of point symmetries is insufficient and the algebra unsuitable for the complete specification of the system. We use the method of reduction of order to reduce the nonlinear fourth-order system to a third-order system comprising a linear second-order equation and a conservation law. We obtain the representat...

  4. [The development of musicality in children after cochlear implantation].

    Science.gov (United States)

    Zheng, Yan; Liu, Bo; Dong, Ruijuan; Xu, Tianqiu; Chen, Jing; Chen, Xuejing; Zhong, Yan; Meng, Chao; Wang, Hong; Chen, Xueqing

    2014-08-01

    The purpose of this study is to analyze the development of musicality in children after cochlear implantation, and provide a clinical database for the evaluation of their musicality. Twenty-six children with cochlear implants (CI group) participated in this research. They received cochlear implants at the age of 11 to 68 months with a mean of 35.6 months. Seventy-six infants as a control group aged from 1 to 24 months with a mean of 6.1 months participated in this study, whose hearing were considered normal by passing the case history collection, high-risk registers for hearing loss and hearing screening using DPOAE. The music and young children with CIs: Musicality Rating Scale was used to evaluate their musicality. The evaluation was performed before cochlear implantation and 1, 3, 6, 9, 12, 24 months after cochlear implantation for children with cochlear implants. The evaluation was also performed at 1, 3, 6, 9, 12, 24 months for children with normal hearing. The mean scores of musicality showed significant improvements with time of CI use for CI group (Pmusicality also showed significant improvements with time for control group (P0.05). Significant difference was noted between the two groups at 24 months (Pmusicality of children with cochlear implants improved significantly with time after cochlear implantation. The most rapid growth was found in the first year after cochlear implantation.

  5. Deterioration of hearing in a cochlear implantee with relapsing polychondritis.

    Science.gov (United States)

    Patrizia, Mancini; Giuseppe, Attanasio; Marika, Viccaro; Roberto, Filipo

    2011-06-01

    We report on a rare case of cochlear implantation in a patient affected by relapsing polychondritis (RP), which over time induced cochlear fibrosis/ossification and deterioration of previously excellent hearing performance. The clinical course was determined by CT scan, electrophysiology, and speech perception data. We conclude that RP is a severe autoimmune connective disorder that can cause profound sensorineural hearing loss. Cochlear implantation in these patients can provide excellent performance. Continuation of therapy may improve prognosis, but relapses involving inner ear structures can determine fibrosis/ossification of the modiolus and interfere with cochlear implant use.

  6. [Multi-channel cochlear implants in patients with Mondini malformation].

    Science.gov (United States)

    Li, Yong-xin; Han, De-min; Zhao, Xiao-tian; Chen, Xue-qing; Kong, Ying; Zheng, Jun; Liu, Bo; Liu, Sha; Mo, Ling-yan; Zhang, Hua; Wang, Shuo

    2004-02-01

    To describe clinical experiences with multi-channel cochlear implantation in patients with Mondini malformation. Among 300 patients who received multi-channel cochlear implants from 1996 to 2002 in Beijing Tongren Hospital, 15 patients were diagnosed with Mondini malformation. A retrospective analysis was performed dealing with the surgical techniques, mapping and rehabilitations characteristics after surgery. 15 patients with normal cochlear structure are consider as control group. Gusher is found more common than the normal cochlear implantation, most of them are serious. The electrodes are inserted in the "cochleostomy" in full length of 13 Patients, 2 pairs of electrodes remains outside of "cochleostomy" in 2 patients. No serious complications occurred after implantation. All patients have auditory sensations. The impedance of the electrodes, the T level, C level and the hearing threshold are similar with the normal cochlear implantation group. The results have no significant difference in compare with normal cochlear group(P > 0.05). Multi-channel cochlear implantation could be performed safely in patients with Mondini malformation. The primary outcome for patients with Mondini malformation are similar to those with normal cochlear structure following the multi-channel cochlear implantation.

  7. Nonlinear analysis

    National Research Council Canada - National Science Library

    Rassias, Themistocles M

    1987-01-01

    ... known that nonlinear partial differential equations can not be treated in the same systematic way as linear ones and this volume provides, among other things, proofs of existence and uniqueness theorems for nonlinear differential equations of a global nature. However, the basic techniques which have proven to be efficient in dealing with li...

  8. Nonlinear systems

    CERN Document Server

    Palmero, Faustino; Lemos, M; Sánchez-Rey, Bernardo; Casado-Pascual, Jesús

    2018-01-01

    This book presents an overview of the most recent advances in nonlinear science. It provides a unified view of nonlinear properties in many different systems and highlights many  new developments. While volume 1 concentrates on mathematical theory and computational techniques and challenges, which are essential for the study of nonlinear science, this second volume deals with nonlinear excitations in several fields. These excitations can be localized and transport energy and matter in the form of breathers, solitons, kinks or quodons with very different characteristics, which are discussed in the book. They can also transport electric charge, in which case they are known as polarobreathers or solectrons. Nonlinear excitations can influence function and structure in biology, as for example, protein folding. In crystals and other condensed matter, they can modify transport properties, reaction kinetics and interact with defects. There are also engineering applications in electric lattices, Josephson junction a...

  9. Incompressible turbulence as non-local field theory

    Indian Academy of Sciences (India)

    However, the shell-to-shell energy transfer is local. Contrast this with Burgers equation which is local in real space. Note that the sound speed in Burgers equation is zero. In our presentation we will contrast these two equations using non-local field theory. Energy spectrum and renormalized parameters will be discussed.

  10. Solvable quantum lattices with nonlocal non-Hermitian endpoint interactions

    Czech Academy of Sciences Publication Activity Database

    Znojil, Miloslav

    2015-01-01

    Roč. 361, OCT (2015), s. 226-246 ISSN 0003-4916 Institutional support: RVO:61389005 Keywords : exactly solvable quantum models * non-Hermitian boundary conditions * new nonlocal boundary conditions * physical inner products Subject RIV: BE - Theoretical Physics Impact factor: 2.375, year: 2015

  11. Effective models of inflation from a nonlocal framework

    Science.gov (United States)

    Koshelev, Alexey S.; Kumar, K. Sravan; Moniz, Paulo Vargas

    2017-11-01

    The dilaton is a possible inflaton candidate following recent CMB data allowing a nonminimal coupling to the Ricci curvature scalar in the early Universe. In this paper, we introduce an approach that has seldom been used in the literature, namely dilaton inflation with non-local features. More concretely, employing non-local features expressed in [J. High Energy Phys. 04 (2007) 029, 10.1088/1126-6708/2007/04/029], we study quadratic variations around a de Sitter geometry of an effective action with a nonlocal dilaton. The nonlocality refers to an infinite derivative kinetic term involving the operator F (□) . Algebraic roots of the characteristic equation F (z )=0 play a crucial role in determining the properties of the theory. We subsequently study the cases when F (□) has one real root and one complex root, from which we retrieve two concrete effective models of inflation. In the first case we retrieve a class of single field inflations with universal prediction of ns˜0.967 with any value of the tensor to scalar ratio r product of scalar fields. In this latter case, we obtain Starobinsky-like inflation through a spontaneously broken conformal invariance. Furthermore, an uplifted minimum of the potential, which accounts for the vacuum energy after inflation is produced naturally through this mechanism intrinsically within our approach.

  12. On a nonlocal Cauchy problem for differential inclusions

    Directory of Open Access Journals (Sweden)

    Y. G. Sficas

    2004-05-01

    Full Text Available We establish sufficient conditions for the existence of solutions for semilinear differential inclusions, with nonlocal conditions. We rely on a fixed-point theorem for contraction multivalued maps due to Covitz and Nadler andon the Schaefer's fixed-point theorem combined with lower semicontinuous multivalued operators with decomposable values.

  13. Nonlocal response in plasmonic waveguiding with extreme light confinement

    DEFF Research Database (Denmark)

    Toscano, Giuseppe; Raza, Søren; Yan, Wei

    2013-01-01

    We present a novel wave equation for linearized plasmonic response, obtained by combining the coupled real-space differential equations for the electric field and current density. Nonlocal dynamics are fully accounted for, and the formulation is very well suited for numerical implementation...

  14. Inhomogeneous broadening in non-interacting nonlocal plasmonic ensembles

    DEFF Research Database (Denmark)

    Tserkezis, Christos; Maack, Johan Rosenkrantz; Liu, Z.

    2016-01-01

    important within the first-order correction to classical electrodynamics provided by the hydrodynamic Drude model, but turn out to be less prominent once additional single-particle size-dependent damping mechanisms are accounted for through the recently developed Generalized Nonlocal Optical Response theory...

  15. Nonlocal formalism for nanoplasmonics: Phenomenological and semi-classical considerations

    DEFF Research Database (Denmark)

    Mortensen, N. Asger

    2013-01-01

    . Without specifying further details of the underlying physical mechanism we show how this leads to a Laplacian correction term in the electromagnetic wave equation. Within the hydrodynamic model we demonstrate this explicitly and we identify the characteristic nonlocal range to be ξNL∼vF/ω where v...

  16. Robustness of the Rabi Splitting under Nonlocal Corrections in Plexcitonics

    DEFF Research Database (Denmark)

    Tserkezis, Christos; Wubs, Martijn; Mortensen, N. Asger

    2018-01-01

    , the influence of nonlocality is rather limited, as in most occasions the width of the Rabi splitting remains largely unaffected and the two hybrid modes are well distinguishable. We discuss how this behavior can be understood in view of the popular coupled-harmonic-oscillator model, while we also provide...

  17. Effects of non-local thermodynamic equilibrium conditions on ...

    Indian Academy of Sciences (India)

    Abstract. Effects of non-local thermodynamic equilibrium (non-LTE) condition on emission and hydrodynamics of typical inertial confinement fusion (ICF) plasmas are studied. The average degree of ionization at high temperatures is seen to be much lower compared to the values obtained from. Thomas–Fermi scaling or ...

  18. Synchronization and suppression of chaos in non-locally coupled ...

    Indian Academy of Sciences (India)

    in ferromagnetic spin models [11], self-organized memories in sliding charge density wave experiments [12] and in the synchronization transition of complex systems. [13]. Other forms of nonlocal couplings that have seen considerable research interest involve a finite number of non-nearest neighbours, such as small-world ...

  19. A nonlocal phase-field system with inertial term

    Czech Academy of Sciences Publication Activity Database

    Grasselli, M.; Petzeltová, Hana; Schimperna, G.

    2007-01-01

    Roč. 65, č. 3 (2007), s. 451-469 ISSN 0033-569X R&D Projects: GA AV ČR(CZ) IAA100190606 Institutional research plan: CEZ:AV0Z10190503 Keywords : nonlocal phase-field system * Lojasiewicz inequality * convergence to equilibria Subject RIV: BA - General Mathematics Impact factor: 0.463, year: 2007

  20. Non-local plasticity effects on fracture toughness

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof

    2002-01-01

    of the effective plastic strain. Fracture is modelled by a cohesive zone criterion. Results on the numerically obtained stress fields are presented, as well as results on the steady-state fracture toughness. It is shown that the nonlocal theory predicts lower steady-state fracture toughness compared to predictions...

  1. Formulation analysis and computation of an optimization-based local-to-nonlocal coupling method.

    Energy Technology Data Exchange (ETDEWEB)

    D' Elia, Marta [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Center for Computing Research; Bochev, Pavel Blagoveston [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Center for Computing Research

    2017-01-01

    In this paper, we present an optimization-based coupling method for local and nonlocal continuum models. Our approach couches the coupling of the models into a control problem where the states are the solutions of the nonlocal and local equations, the objective is to minimize their mismatch on the overlap of the local and nonlocal problem domains, and the virtual controls are the nonlocal volume constraint and the local boundary condition. We present the method in the context of Local-to-Nonlocal di usion coupling. Numerical examples illustrate the theoretical properties of the approach.

  2. A higher-order nonlocal elasticity and strain gradient theory and its applications in wave propagation

    Science.gov (United States)

    Lim, C. W.; Zhang, G.; Reddy, J. N.

    2015-05-01

    In recent years there have been many papers that considered the effects of material length scales in the study of mechanics of solids at micro- and/or nano-scales. There are a number of approaches and, among them, one set of papers deals with Eringen's differential nonlocal model and another deals with the strain gradient theories. The modified couple stress theory, which also accounts for a material length scale, is a form of a strain gradient theory. The large body of literature that has come into existence in the last several years has created significant confusion among researchers about the length scales that these various theories contain. The present paper has the objective of establishing the fact that the length scales present in nonlocal elasticity and strain gradient theory describe two entirely different physical characteristics of materials and structures at nanoscale. By using two principle kernel functions, the paper further presents a theory with application examples which relates the classical nonlocal elasticity and strain gradient theory and it results in a higher-order nonlocal strain gradient theory. In this theory, a higher-order nonlocal strain gradient elasticity system which considers higher-order stress gradients and strain gradient nonlocality is proposed. It is based on the nonlocal effects of the strain field and first gradient strain field. This theory intends to generalize the classical nonlocal elasticity theory by introducing a higher-order strain tensor with nonlocality into the stored energy function. The theory is distinctive because the classical nonlocal stress theory does not include nonlocality of higher-order stresses while the common strain gradient theory only considers local higher-order strain gradients without nonlocal effects in a global sense. By establishing the constitutive relation within the thermodynamic framework, the governing equations of equilibrium and all boundary conditions are derived via the variational

  3. Nonlocal free vibration in the pre- and post-buckled states of magneto-electro-thermo elastic rectangular nanoplates with various edge conditions

    Science.gov (United States)

    Ansari, R.; Gholami, R.

    2016-09-01

    Considering the small scale effect together with the influences of transverse shear deformation, rotary inertia and the magneto-electro-thermo-mechanical coupling, the linear free vibration of magneto-electro-thermo-elastic (METE) rectangular nanoplates with various edge supports in pre- and post-buckled states is investigated herein. It is assumed that the METE nanoplate is subjected to the external in-plane compressive loads in combination with magnetic, electric and thermal loads. The Mindlin plate theory, von Kármán hypothesis and the nonlocal theory are utilized to develop a size-dependent geometrically nonlinear plate model for describing the size-dependent linear and nonlinear mechanical characteristics of moderately thick METE rectangular nanoplates. The nonlinear governing equations and the corresponding boundary conditions are derived using Hamilton’s principle which are then discretized via the generalized differential quadrature method. The pseudo-arc length continuation approach is used to obtain the equilibrium postbuckling path of METE nanoplates. By the obtained postbuckling response, and taking a time-dependent small disturbance around the buckled configuration, and inserting them into the nonlinear governing equations, an eigenvalue problem is achieved from which the frequencies of pre- and post-buckled METE nanoplates can be calculated. The effects of nonlocal parameter, electric, magnetic and thermal loadings, length-to-thickness ratio and different boundary conditions on the free vibration response of METE rectangular nanoplates in the pre- and post-buckled states are highlighted.

  4. Characteristics of electrically evoked auditory brainstem responses in patients with cochlear nerve canal stenosis receiving cochlear implants.

    Science.gov (United States)

    Wang, Zhenxiao; Liu, Yun; Wang, Line; Shen, Xixi; Han, Shuguang; Wang, Wei; Gao, Fenqi; Liang, Wenqi; Peng, Kevin A

    2018-01-01

    To explore the characteristics of the electrically evoked auditory brainstem responses (EABR) in children with cochlear nerve canal stenosis (CNCs) following cochlear implantation (CI), and the EABR thresholds in children with stenotic versus normal cochlear nerve canals. Sixteen children with profound sensorineural hearing loss were included in this study: 8 with CNCs (CNCs group) and 8 with normal cochlear nerve canals (control group). All children underwent cochlear implantation with full insertion of all electrodes. EABR was performed 6 months postoperatively in both groups. The EABR extraction rate was 100% in children with normal cochlear nerve canals and only 50% in children with CNCs. EABR thresholds were significantly higher in children with CNCs of electrodes No. 11and 22 than in children with normal cochlear nerve canals (P  0.05 for all comparisons); while in the control group, the EABR threshold at electrode No 22 was lower than those at both electrodes No. 11 and 1 (P cochlear nerve canals vary according to the different locations of electrodes in the cochlea; while in children with CNCs, there was no significant difference among different electrode locations. The EABR thresholds in CNCs children were higher than those of children with normal cochlear nerve canals at electrode 11 and 22. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Dispersive shock waves in systems with nonlocal dispersion of Benjamin-Ono type

    Science.gov (United States)

    El, G. A.; Nguyen, L. T. K.; Smyth, N. F.

    2018-04-01

    We develop a general approach to the description of dispersive shock waves (DSWs) for a class of nonlinear wave equations with a nonlocal Benjamin-Ono type dispersion term involving the Hilbert transform. Integrability of the governing equation is not a pre-requisite for the application of this method which represents a modification of the DSW fitting method previously developed for dispersive-hydrodynamic systems of Korteweg-de Vries (KdV) type (i.e. reducible to the KdV equation in the weakly nonlinear, long wave, unidirectional approximation). The developed method is applied to the Calogero-Sutherland dispersive hydrodynamics for which the classification of all solution types arising from the Riemann step problem is constructed and the key physical parameters (DSW edge speeds, lead soliton amplitude, intermediate shelf level) of all but one solution type are obtained in terms of the initial step data. The analytical results are shown to be in excellent agreement with results of direct numerical simulations.

  6. Auditory neuroplasticity, hearing loss and cochlear implants.

    Science.gov (United States)

    Ryugo, David

    2015-07-01

    Data from our laboratory show that the auditory brain is highly malleable by experience. We establish a base of knowledge that describes the normal structure and workings at the initial stages of the central auditory system. This research is expanded to include the associated pathology in the auditory brain stem created by hearing loss. Utilizing the congenitally deaf white cat, we demonstrate the way that cells, synapses, and circuits are pathologically affected by sound deprivation. We further show that the restoration of auditory nerve activity via electrical stimulation through cochlear implants serves to correct key features of brain pathology caused by hearing loss. The data suggest that rigorous training with cochlear implants and/or hearing aids offers the promise of heretofore unattained benefits.

  7. Cochlear pathology: CT and MRI findings

    International Nuclear Information System (INIS)

    Martinez, Manuel; Bruno, Claudio; Martin, Eduardo; Canale, Nancy; De Luca, Laura; Spina, Juan C. h

    2002-01-01

    The authors present a retrospective analysis of 50 patients with perceptive hearing loss. The neuro physiological work-up (evoked potentials, audiometric tests and otoemissions) identified the cochlea as the site of origin of the hearing loss. The imaging studies (high resolution CT and MR, including 3D volumes) showed petrous bone trauma (n=5) infections (bacterial or viral origin) (n=12) otosclerosis (n=8), Paget disease (n=3), and labyrinthine neurinomas (n=2). The other 20 cases showed development-linked disorders (Mitchel's, Mondini, Scheibe, Alexander, and hypoplasia of the cochlear canal). Imaging with CT and MR can identify in detail the structural abnormality affecting the cochlea and occasionally the immediate peri-cochlear region (otic capsule); the affected portion of the cochlea may thus be determined. (author)

  8. Cochlear implant; Sharecropping discoveries vs surgical

    International Nuclear Information System (INIS)

    Mantilla M, Maria T; Pachon L, Francisco; Garcia, Juan M; Penaranda, Augusto

    1997-01-01

    Computed tomography (CT) of the ear is an important tool to decide if a patient is a candidate for cochlear implant. CT is a keystone in planning the surgery. Our purpose was to find out the incidence of anormalities and aetiologies in 84 patients with neuro sensorial hearing loss, submitted to a cochlear implant; establishing a correlation between the pre-implant high resolution computed tomography (HRTC) scans and the surgical findings. The most common causes of hearing loss were idiopathic (37/84), rubella (16/84), congenital anomaly (8/84), ototoxic medication (7/84), meningitis (6/84) and trauma (6/84). Sixteen abnormalities or anatomical features relevant for surgery were found in the 84 HRCT. Most of these findings were detected in the cochlea (11/84) and the vestibular aqueduct (6/84); the former related to labyrinthitis ossificans and Mondini anomaly, and the latter secondary to a large vestibular aqueduct

  9. Meningitis after cochlear implantation in Mondini malformation.

    Science.gov (United States)

    Page, E L; Eby, T L

    1997-01-01

    Although the potential for CSF leakage and subsequent meningitis after cochlear implantation in the malformed cochlea has been recognized, this complication has not been previously reported. We report a case of CSF otorhinorrhea and meningitis after minor head trauma developing 2 years after cochlear implantation in a child with Mondini malformation. Leakage of CSF was identified from the cochleostomy around the electrode of the implant, and this leak was sealed with a temporalis fascia and muscle plug. Although this complication appears to be rare, care must be taken to seal the cochleostomy in children with inner ear malformations at the initial surgery, and any episode of meningitis after surgery must be thoroughly investigated to rule out CSF leakage from the labyrinth.

  10. An approach for quantitatively analyzing the genuine tripartite nonlocality of general three-qubit states

    Science.gov (United States)

    Su, Zhaofeng; Li, Lvzhou; Ling, Jie

    2018-04-01

    Nonlocality is an important resource for quantum information processing. Genuine tripartite nonlocality, which is sufficiently confirmed by the violation of Svetlichny inequality, is a kind of more precious resource than the standard one. The genuine tripartite nonlocality is usually quantified by the amount of maximal violation of Svetlichny inequality. The problem of detecting and quantifying the genuine tripartite nonlocality of quantum states is of practical significance but still open for the case of general three-qubit quantum states. In this paper, we quantitatively investigate the genuine nonlocality of three-qubit states, which not only include pure states but also include mixed states. Firstly, we derive a simplified formula for the genuine nonlocality of a general three-qubit state, which is a function of the corresponding three correlation matrices. Secondly, we develop three properties of the genuine nonlocality which can help us to analyze the genuine nonlocality of complex states and understand the nature of quantum nonlocality. Further, we get analytical results of genuine nonlocality for two classes of three-qubit states which have special correlation matrices. In particular, the genuine nonlocality of generalized three-qubit GHZ states, which is derived by Ghose et al. (Phys. Rev. Lett. 102, 250404, 2009), and that of three-qubit GHZ-symmetric states, which is derived by Paul et al. (Phys. Rev. A 94, 032101, 2016), can be easily derived by applying the strategy and properties developed in this paper.

  11. Non-local optical potential: theoretical and phenomenological aspects

    International Nuclear Information System (INIS)

    Giannini, M.M.; Ricco, G.

    1976-01-01

    The general expression of the nucleon-nucleus optical potential has been obtained using Watson's multiple scattering theory and Wolfenstein's parametrization of the nucleon-nucleon scattering amplitude. The resulting theoretical potential is non-local and consists of an energy independent central volume plus surface real and imaginary potential and of a Thomas-like spin-orbit term. The analysis has been restricted to N=Z spherical nuclei, so that neither isospin-isospin nor spin-spin interaction have been included. The widely used Perey-Buck, Greenlees and Watson expressions of the optical potential are easily obtained as particular cases. For practical purposes the non-local potential has been parametrized in the Frahn-Lemmer form, using Woods-Saxon radial form factors and the equivalent local potential (ELP) has been calculated by a Perey-Buck-like transformation. The ELP has a radial behaviour very similar to the original non-local one, but the potential depths and radii are energy dependent. The six free parameters in the ELP have been adjusted to fit the available experimental data in the -70 up to +150 MeV range of interest in nuclear reactions, namely energies of single hole and single particle states, charge distributions, proton elastic scattering cross sections and polarizations. The fitted potential depths show an energy dependence in remarkable agreement with the model predictions with a central non-locality range β approximately equal to 1.fm and a spin-orbit non-locality range βsub(s) = 0.8 fm. The relative importance of surface and volume dependence in the real central potential is also discussed. (orig.) [de

  12. Simplifying cochlear implant speech processor fitting

    OpenAIRE

    Willeboer, C.

    2008-01-01

    Conventional fittings of the speech processor of a cochlear implant (CI) rely to a large extent on the implant recipient's subjective responses. For each of the 22 intracochlear electrodes the recipient has to indicate the threshold level (T-level) and comfortable loudness level (C-level) while stimulated with pulse trains. Obtaining these behavioral measurements is a time-consuming task. It requires cooperation and considerable effort of the CI recipient. Especially in adults that have been ...

  13. LIBRAS AND COCHLEAR IMPLANT: CONTRADICTION OR COMPLEMENTARITY?

    OpenAIRE

    Lilian Cristine Ribeiro Nascimento; Cibelle Carlos Sousa Lima

    2015-01-01

    This paper analyses the answers for the interviews carried out with deaf children´s parents about their decision for the rehabilitation and education of their kids, decision which is marked by the simultaneous choice of submitting them to cochlear implant surgery and the exposition to the Brazilian Sign Language. The research’s methodology adopted the historical criticism and the psychoanalysis - hermeneutic analysis for the eight interviews carried out with parents of the children who are re...

  14. Hearing Preservation in Cochlear Implant Surgery

    Directory of Open Access Journals (Sweden)

    Priscila Carvalho Miranda

    2014-01-01

    Full Text Available In the past, it was thought that hearing loss patients with residual low-frequency hearing would not be good candidates for cochlear implantation since insertion was expected to induce inner ear trauma. Recent advances in electrode design and surgical techniques have made the preservation of residual low-frequency hearing achievable and desirable. The importance of preserving residual low-frequency hearing cannot be underestimated in light of the added benefit of hearing in noisy atmospheres and in music quality. The concept of electrical and acoustic stimulation involves electrically stimulating the nonfunctional, high-frequency region of the cochlea with a cochlear implant and applying a hearing aid in the low-frequency range. The principle of preserving low-frequency hearing by a “soft surgery” cochlear implantation could also be useful to the population of children who might profit from regenerative hair cell therapy in the future. Main aspects of low-frequency hearing preservation surgery are discussed in this review: its brief history, electrode design, principles and advantages of electric-acoustic stimulation, surgical technique, and further implications of this new treatment possibility for hearing impaired patients.

  15. Nonlinear optics

    CERN Document Server

    Boyd, Robert W

    2013-01-01

    Nonlinear Optics is an advanced textbook for courses dealing with nonlinear optics, quantum electronics, laser physics, contemporary and quantum optics, and electrooptics. Its pedagogical emphasis is on fundamentals rather than particular, transitory applications. As a result, this textbook will have lasting appeal to a wide audience of electrical engineering, physics, and optics students, as well as those in related fields such as materials science and chemistry.Key Features* The origin of optical nonlinearities, including dependence on the polarization of light* A detailed treatment of the q

  16. Exploring Perspectives on Cochlear Implants and Language Acquisition within the Deaf Community

    Science.gov (United States)

    Gale, Elaine

    2011-01-01

    Cochlear implants generated intense debate almost immediately following their introduction in the 1980s. Today, with a vast number of deaf individuals with cochlear implants, the debate about the cochlear implant device and mode of communication continues. Q-methodology was used in this study to explore cochlear implants and language acquisition…

  17. Nonlinear reconstruction

    Science.gov (United States)

    Zhu, Hong-Ming; Yu, Yu; Pen, Ue-Li; Chen, Xuelei; Yu, Hao-Ran

    2017-12-01

    We present a direct approach to nonparametrically reconstruct the linear density field from an observed nonlinear map. We solve for the unique displacement potential consistent with the nonlinear density and positive definite coordinate transformation using a multigrid algorithm. We show that we recover the linear initial conditions up to the nonlinear scale (rδrδL>0.5 for k ≲1 h /Mpc ) with minimal computational cost. This reconstruction approach generalizes the linear displacement theory to fully nonlinear fields, potentially substantially expanding the baryon acoustic oscillations and redshift space distortions information content of dense large scale structure surveys, including for example SDSS main sample and 21 cm intensity mapping initiatives.

  18. Nonlinear analysis

    CERN Document Server

    Gasinski, Leszek

    2005-01-01

    Hausdorff Measures and Capacity. Lebesgue-Bochner and Sobolev Spaces. Nonlinear Operators and Young Measures. Smooth and Nonsmooth Analysis and Variational Principles. Critical Point Theory. Eigenvalue Problems and Maximum Principles. Fixed Point Theory.

  19. Emotion Understanding in Deaf Children with a Cochlear Implant

    Science.gov (United States)

    Wiefferink, Carin H.; Rieffe, Carolien; Ketelaar, Lizet; De Raeve, Leo; Frijns, Johan H. M.

    2013-01-01

    It is still largely unknown how receiving a cochlear implant affects the emotion understanding in deaf children. We examined indices for emotion understanding and their associations with communication skills in children aged 2.5-5 years, both hearing children (n = 52) and deaf children with a cochlear implant (n = 57). 2 aspects of emotion…

  20. Serving Deaf Students Who Have Cochlear Implants. PEPNet Tipsheet

    Science.gov (United States)

    Searls, J. Matt, Comp.

    2010-01-01

    Cochlear implants (CIs) are complex electronic devices surgically implanted under the skin behind the ear. These devices utilize electrodes placed in the inner ear (the cochlea) to stimulate the auditory nerve of individuals with significant permanent hearing loss. Cochlear implants may not be suitable for everyone. They are designed to provide…

  1. Early Vocabulary Development in Children with Bilateral Cochlear Implants

    Science.gov (United States)

    Välimaa, Taina; Kunnari, Sari; Laukkanen-Nevala, Päivi; Lonka, Eila

    2018-01-01

    Background: Children with unilateral cochlear implants (CIs) may have delayed vocabulary development for an extended period after implantation. Bilateral cochlear implantation is reported to be associated with improved sound localization and enhanced speech perception in noise. This study proposed that bilateral implantation might also promote…

  2. Evaluating the Feasibility of Using Remote Technology for Cochlear Implants

    Science.gov (United States)

    Goehring, Jenny L.; Hughes, Michelle L.; Baudhuin, Jacquelyn L.

    2012-01-01

    The use of remote technology to provide cochlear implant services has gained popularity in recent years. This article contains a review of research evaluating the feasibility of remote service delivery for recipients of cochlear implants. To date, published studies have determined that speech-processor programming levels and other objective tests…

  3. Developing Auditory Learning in Children with Cochlear Implants.

    Science.gov (United States)

    Schery, Teris K.; Peters, Mary Love

    2003-01-01

    This article reviews research studies on the efficacy of cochlear implants for children's auditory communication skills, including speech perception, speech production, and language. It offers suggestions for building auditory skill development in children with cochlear implants. Four classic levels of auditory skill development (awareness,…

  4. Remote programming of cochlear implants: a telecommunications model.

    Science.gov (United States)

    McElveen, John T; Blackburn, Erin L; Green, J Douglas; McLear, Patrick W; Thimsen, Donald J; Wilson, Blake S

    2010-09-01

    Evaluate the effectiveness of remote programming for cochlear implants. Retrospective review of the cochlear implant performance for patients who had undergone mapping and programming of their cochlear implant via remote connection through the Internet. Postoperative Hearing in Noise Test and Consonant/Nucleus/Consonant word scores for 7 patients who had undergone remote mapping and programming of their cochlear implant were compared with the mean scores of 7 patients who had been programmed by the same audiologist over a 12-month period. Times required for remote and direct programming were also compared. The quality of the Internet connection was assessed using standardized measures. Remote programming was performed via a virtual private network with a separate software program used for video and audio linkage. All 7 patients were programmed successfully via remote connectivity. No untoward patient experiences were encountered. No statistically significant differences could be found in comparing postoperative Hearing in Noise Test and Consonant/Nucleus/Consonant word scores for patients who had undergone remote programming versus a similar group of patients who had their cochlear implant programmed directly. Remote programming did not require a significantly longer programming time for the audiologist with these 7 patients. Remote programming of a cochlear implant can be performed safely without any deterioration in the quality of the programming. This ability to remotely program cochlear implant patients gives the potential to extend cochlear implantation to underserved areas in the United States and elsewhere.

  5. Taxonomic Knowledge of Children with and without Cochlear Implants

    Science.gov (United States)

    Lund, Emily; Dinsmoor, Jessica

    2016-01-01

    Purpose: The purpose of this study was to compare the taxonomic vocabulary knowledge and organization of children with cochlear implants to (a) children with normal hearing matched for age, and (b) children matched for vocabulary development. Method: Ten children with cochlear implants, 10 age-matched children with normal hearing, and 10…

  6. Speech Intelligibility and Prosody Production in Children with Cochlear Implants

    Science.gov (United States)

    Chin, Steven B.; Bergeson, Tonya R.; Phan, Jennifer

    2012-01-01

    Objectives: The purpose of the current study was to examine the relation between speech intelligibility and prosody production in children who use cochlear implants. Methods: The Beginner's Intelligibility Test (BIT) and Prosodic Utterance Production (PUP) task were administered to 15 children who use cochlear implants and 10 children with normal…

  7. Are parents of children with cochlear implants coping?: research ...

    African Journals Online (AJOL)

    Many variables must be considered during the evaluation and rehabilitation of children for cochlear implantation, one of which is parental influence (for the duration of this report the parents, caregivers and guardians of children with cochlear implants and / or hearing impairments will be referred to as 'parents'). The aim of ...

  8. The long-term concerns post cochlear implantation as experienced ...

    African Journals Online (AJOL)

    Background. Cochlear implantation aims to provide an effective means of spoken communication for prelingually deaf children. However, studies in this field are mostly clinically orientated, with little focus on the experiences and long-term concerns of families post cochlear implantation (CI). Objective. To describe the ...

  9. Practical Nonlinearities

    Science.gov (United States)

    2016-07-01

    architectures , practical nonlinearities, nonlinear dynamics 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT: SAR 8. NUMBER OF PAGES...performers from Mesodynamic Architectures (MESO) and uPNT all to include devices in these runs. This cost-sharing was planned, and is necessary for...contributions to the performance of MEMS gyroscopes. In particular, we have demonstrated for the first time that Parametric Amplification can improve the

  10. Gain and frequency tuning within the mouse cochlear apex

    Energy Technology Data Exchange (ETDEWEB)

    Oghalai, John S.; Raphael, Patrick D. [Department of Otolaryngology, Stanford University School of Medicine, Stanford, California (United States); Gao, Simon [Department of Otolaryngology, Stanford University School of Medicine, Stanford, California (United States); Department of Bioengineering, Rice University, Houston, Texas (United States); Lee, Hee Yoon [Department of Otolaryngology, Stanford University School of Medicine, Stanford, California (United States); Department of Electrical Engineering, Stanford University, Stanford, California (United States); Groves, Andrew K. [Department of Neuroscience, Department of Molecular and Human Genetics, and Program in Developmental Biology, Baylor College of Medicine, Houston, Texas (United States); Zuo, Jian [Department of Developmental Neurobiology, St. Jude Children’s Research Hospital, Memphis, Tennessee (United States); Applegate, Brian E. [Department of Biomedical Engineering, Texas A& M University, College Station, Texas (United States)

    2015-12-31

    Normal mammalian hearing requires cochlear outer hair cell active processes that amplify the traveling wave with high gain and sharp tuning, termed cochlear amplification. We have used optical coherence tomography to study cochlear amplification within the apical turn of the mouse cochlea. We measured not only classical basilar membrane vibratory tuning curves but also vibratory responses from the rest of the tissues that compose the organ of Corti. Basilar membrane tuning was sharp in live mice and broad in dead mice, whereas other regions of the organ of Corti demonstrated phase shifts consistent with additional filtering beyond that provided by basilar membrane mechanics. We use these experimental data to support a conceptual framework of how cochlear amplification is tuned within the mouse cochlear apex. We will also study transgenic mice with targeted mutations that affect different biomechanical aspects of the organ of Corti in an effort to localize the underlying processes that produce this additional filtering.

  11. The Hearing Outcomes of Cochlear Implantation in Waardenburg Syndrome.

    Science.gov (United States)

    Koyama, Hajime; Kashio, Akinori; Sakata, Aki; Tsutsumiuchi, Katsuhiro; Matsumoto, Yu; Karino, Shotaro; Kakigi, Akinobu; Iwasaki, Shinichi; Yamasoba, Tatsuya

    2016-01-01

    Objectives. This study aimed to determine the feasibility of cochlear implantation for sensorineural hearing loss in patients with Waardenburg syndrome. Method. A retrospective chart review was performed on patients who underwent cochlear implantation at the University of Tokyo Hospital. Clinical classification, genetic mutation, clinical course, preoperative hearing threshold, high-resolution computed tomography of the temporal bone, and postoperative hearing outcome were assessed. Result. Five children with Waardenburg syndrome underwent cochlear implantation. The average age at implantation was 2 years 11 months (ranging from 1 year 9 months to 6 years 3 months). Four patients had congenital profound hearing loss and one patient had progressive hearing loss. Two patients had an inner ear malformation of cochlear incomplete partition type 2. No surgical complication or difficulty was seen in any patient. All patients showed good hearing outcome postoperatively. Conclusion. Cochlear implantation could be a good treatment option for Waardenburg syndrome.

  12. The Hearing Outcomes of Cochlear Implantation in Waardenburg Syndrome

    Directory of Open Access Journals (Sweden)

    Hajime Koyama

    2016-01-01

    Full Text Available Objectives. This study aimed to determine the feasibility of cochlear implantation for sensorineural hearing loss in patients with Waardenburg syndrome. Method. A retrospective chart review was performed on patients who underwent cochlear implantation at the University of Tokyo Hospital. Clinical classification, genetic mutation, clinical course, preoperative hearing threshold, high-resolution computed tomography of the temporal bone, and postoperative hearing outcome were assessed. Result. Five children with Waardenburg syndrome underwent cochlear implantation. The average age at implantation was 2 years 11 months (ranging from 1 year 9 months to 6 years 3 months. Four patients had congenital profound hearing loss and one patient had progressive hearing loss. Two patients had an inner ear malformation of cochlear incomplete partition type 2. No surgical complication or difficulty was seen in any patient. All patients showed good hearing outcome postoperatively. Conclusion. Cochlear implantation could be a good treatment option for Waardenburg syndrome.

  13. Unilateral musical hallucination after a hybrid cochlear implantation.

    Science.gov (United States)

    Joe, Soohyun; Park, Jangho; Lim, Jongseok; Park, Choongman

    2015-01-01

    To provide a description of musical hallucination associated with hybrid cochlear implantation. Case report. We report a case of musical hallucination secondary to hybrid cochlear implantation. Activation of electrical stimulation was closely related to onset of musical hallucination and deactivation was associated with attenuation of hallucination. Persistent musical hallucination severely impaired speech discrimination in spite of 2 years of listening rehabilitation. The hybrid cochlear implant is a relatively new surgical method, and its side effects have not been well documented. This is the first report of musical hallucination after a hybrid cochlear implantation. Also we provide evidence of the peripheral origin of musical hallucination by reporting lateralization and intensity change of hallucination by activation status of cochlear implant. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. Comparison of Dizziness, Depression, Anxiety and Mental Health of Postlingually Deaf Adults Between Cochlear Implant Recipients and Cochlear Implant Candidates

    Directory of Open Access Journals (Sweden)

    Reza Hossein-Abadi

    2008-07-01

    Full Text Available Objective: Hearing loss can affect on physical, mental and social health of deaf adults and lead to depression, anxiety, isolation, suspicion and stress of them. Cochlear implantation has positive effects on behavioral and emotional status of postlingually hearing impaired adults. This study is aimed to compare dizziness, depression, anxiety and mental health in adult cochlear implant recipients and candidates. Materials & Methods: This case- control and comparative study was conducted on 49 patients, 24 cochlear implant recipients (as case group and 25 severe-profound hearing impaired adults (as control groups whom were selected by simple and convenient sampling. Beck Depression Inventory, Dizziness Handicap Inventory, Beck Anxiety Inventory and General Health Questionnaire were completed to determine and compare cochlear implant effects. Data were analyzed by MANOVA. Results: Mean depression and anxiety scores in cochlear implant candidates were more than cochlear implant recipients. This difference was significant in depression (P=0.001. There was no significant difference between two groups in general health (P=0.415. The results of this study also showed that dizziness is more in cochlear implanted group (P=0.004. Conclusion: It seems that cochlear implant use leads to decrease of depression and anxiety. It leads to increase of dizziness.

  15. Assessment of Cochlear Function during Cochlear Implantation by Extra- and Intracochlear Electrocochleography

    Science.gov (United States)

    Dalbert, Adrian; Pfiffner, Flurin; Hoesli, Marco; Koka, Kanthaiah; Veraguth, Dorothe; Roosli, Christof; Huber, Alexander

    2018-01-01

    Objective: The aims of this study were: (1) To investigate the correlation between electrophysiological changes during cochlear implantation and postoperative hearing loss, and (2) to detect the time points that electrophysiological changes occur during cochlear implantation. Material and Methods: Extra- and intracochlear electrocochleography (ECoG) were used to detect electrophysiological changes during cochlear implantation. Extracochlear ECoG recordings were conducted through a needle electrode placed on the promontory; for intracochlear ECoG recordings, the most apical contact of the cochlear implant (CI) electrode itself was used as the recording electrode. Tone bursts at 250, 500, 750, and 1000 Hz were used as low-frequency acoustic stimuli and clicks as high-frequency acoustic stimuli. Changes of extracochlear ECoG recordings after full insertion of the CI electrode were correlated with pure-tone audiometric findings 4 weeks after surgery. Results: Changes in extracochlear ECoG recordings correlated with postoperative hearing change (r = −0.44, p = 0.055, n = 20). Mean hearing loss in subjects without decrease or loss of extracochlear ECoG signals was 12 dB, compared to a mean hearing loss of 22 dB in subjects with a detectable decrease or a loss of ECoG signals (p = 0.0058, n = 51). In extracochlear ECoG recordings, a mean increase of the ECoG signal of 4.4 dB occurred after opening the cochlea. If a decrease of ECoG signals occurred during insertion of the CI electrode, the decrease was detectable during the second half of the insertion. Conclusion: ECoG recordings allow detection of electrophysiological changes in the cochlea during cochlear implantation. Decrease of extracochlear ECoG recordings during surgery has a significant correlation with hearing loss 4 weeks after surgery. Trauma to cochlear structures seems to occur during the final phase of the CI electrode insertion. Baseline recordings for extracochlear ECoG recordings should be conducted

  16. Stability issues of black hole in non-local gravity

    Science.gov (United States)

    Myung, Yun Soo; Park, Young-Jai

    2018-04-01

    We discuss stability issues of Schwarzschild black hole in non-local gravity. It is shown that the stability analysis of black hole for the unitary and renormalizable non-local gravity with γ2 = - 2γ0 cannot be performed in the Lichnerowicz operator approach. On the other hand, for the unitary and non-renormalizable case with γ2 = 0, the black hole is stable against the metric perturbations. For non-unitary and renormalizable local gravity with γ2 = - 2γ0 = const (fourth-order gravity), the small black holes are unstable against the metric perturbations. This implies that what makes the problem difficult in stability analysis of black hole is the simultaneous requirement of unitarity and renormalizability around the Minkowski spacetime.

  17. Positive solutions for nonlocal dispersal equation with spatial degeneracy

    Science.gov (United States)

    Sun, Jian-Wen

    2018-02-01

    In this paper, we consider the positive solutions of the nonlocal dispersal equation \\int \\limits _{Ω }J(x,y)[u(y)-u(x)]dy=-λ m(x)u(x)+[c(x)+ɛ ]u^p(x) \\quad { in }\\bar{Ω }, where Ω \\subset R^N is a bounded domain, λ ,ɛ and p>1 are positive constants. The dispersal kernel J and the coefficient c( x) are nonnegative, but c( x) has a degeneracy in some subdomain of Ω . In order to study the influence of heterogeneous environment on the nonlocal system, we study the sharp spatial patterns of positive solutions as ɛ → 0. We obtain that the positive solutions always have blow-up asymptotic profiles in \\bar{Ω }. Meanwhile, we find that the profiles in degeneracy domain are different from the domain without degeneracy.

  18. On the compatible weakly nonlocal Poisson brackets of hydrodynamic type

    Directory of Open Access Journals (Sweden)

    Andrei Ya. Maltsev

    2002-01-01

    of hydrodynamic type (Ferapontov brackets and the corresponding integrable hierarchies. We show that, under the requirement of the nondegeneracy of the corresponding “first” pseudo-Riemannian metric g(0 νμ and also some nondegeneracy requirement for the nonlocal part, it is possible to introduce a “canonical” set of “integrable hierarchies” based on the Casimirs, momentum functional and some “canonical Hamiltonian functions.” We prove also that all the “higher” “positive” Hamiltonian operators and the “negative” symplectic forms have the weakly nonlocal form in this case. The same result is also true for “negative” Hamiltonian operators and “positive” symplectic structures in the case when both pseudo-Riemannian metrics g(0 νμ and g(1 νμ are nondegenerate.

  19. Uncertainty estimation in diffusion MRI using the nonlocal bootstrap.

    Science.gov (United States)

    Yap, Pew-Thian; An, Hongyu; Chen, Yasheng; Shen, Dinggang

    2014-08-01

    In this paper, we propose a new bootstrap scheme, called the nonlocal bootstrap (NLB) for uncertainty estimation. In contrast to the residual bootstrap, which relies on a data model, or the repetition bootstrap, which requires repeated signal measurements, NLB is not restricted by the data structure imposed by a data model and obviates the need for time-consuming multiple acquisitions. NLB hinges on the observation that local imaging information recurs in an image. This self-similarity implies that imaging information coming from spatially distant (nonlocal) regions can be exploited for more effective estimation of statistics of interest. Evaluations using in silico data indicate that NLB produces distribution estimates that are in closer agreement with those generated using Monte Carlo simulations, compared with the conventional residual bootstrap. Evaluations using in vivo data demonstrate that NLB produces results that are in agreement with our knowledge on white matter architecture.

  20. Nonlocal transformation of the internal quantum particle structure

    Directory of Open Access Journals (Sweden)

    Alexey Yu. Samarin

    2016-09-01

    Full Text Available The analysis of the integral wave equation, having path integral kernel, has resulted, that collapse phenomenon is based on the nonlocal transformation of the internal structure of a quantum particle, considering in the form of the matter fields collection. This nonlocality allows to escape the contradiction between the reduction quantum mechanics postulate and special relativity. It is shown, that the wave function transformation, corresponding to von Neumann's reduction, has the deterministic nature and the quantum mechanics stochasticity is a consequence of a macroscopic measurer presence in the measuring process. Besides it is demonstrated, that the decogerence phenomenon has the same mechanism of the wave function transformation. EPR-type experiment is described in detail and the possibility of the faster-then light communication is proved, as well the possible rules of thumb of this communication are proposed.

  1. Nonlocal spin-transport measurement of superconductor-ferromagnet nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Kolenda, Stefan; Wolf, Michael J.; Huebler, Florian; Beckmann, Detlef [Institut fuer Nanotechnologie, Karlsruher Institut fuer Technologie (Germany)

    2015-07-01

    We present measurements of the nonlocal conductance of nanostructures with several ferromagnetic electrodes lying perpendicular on a superconducting wire. In these structures nonlocal conductance is mostly given by diffusion of quasiparticles, which are injected by one of the electrodes and detected by an other one. Applying a magnetic field induces a Zeeman splitting in the quasiparticles density of states, which suppresses the relaxation of injected spin imbalance, thus spin transport over distances of several micrometers is found. While in the previous experiments the magnetic field was aligned parallel to the ferromagnetic electrodes, we also show measurements applying the magnetic field noncollinear with the magnetization of the ferromagnetic electrodes. We compare our results to the previous case.

  2. On a class of nonlocal wave equations from applications

    Science.gov (United States)

    Beyer, Horst Reinhard; Aksoylu, Burak; Celiker, Fatih

    2016-06-01

    We study equations from the area of peridynamics, which is a nonlocal extension of elasticity. The governing equations form a system of nonlocal wave equations. We take a novel approach by applying operator theory methods in a systematic way. On the unbounded domain ℝn, we present three main results. As main result 1, we find that the governing operator is a bounded function of the governing operator of classical elasticity. As main result 2, a consequence of main result 1, we prove that the peridynamic solutions strongly converge to the classical solutions by utilizing, for the first time, strong resolvent convergence. In addition, main result 1 allows us to incorporate local boundary conditions, in particular, into peridynamics. This avenue of research is developed in companion papers, providing a remedy for boundary effects. As main result 3, employing spherical Bessel functions, we give a new practical series representation of the solution which allows straightforward numerical treatment with symbolic computation.

  3. Non-local heating theory inductively coupled plasma discharge

    International Nuclear Information System (INIS)

    Yoon, N.S.; You, K.I.; Hwang, S.M.; Choi, D.I.

    1998-01-01

    Recently developed one- and two-dimensional non-local heating theories of planar type inductively coupled plasma discharge are reviewed and some extensions of the results are presented. The important results of the one- and two-dimensional theories are integrated into the representative concepts of surface impedance and impedance of plasma respectively. Relevant physics are discussed and the works in progress are presented. (author)

  4. Genuinely high-dimensional nonlocality optimized by complementary measurements

    International Nuclear Information System (INIS)

    Lim, James; Ryu, Junghee; Yoo, Seokwon; Lee, Changhyoup; Bang, Jeongho; Lee, Jinhyoung

    2010-01-01

    Qubits exhibit extreme nonlocality when their state is maximally entangled and this is observed by mutually unbiased local measurements. This criterion does not hold for the Bell inequalities of high-dimensional systems (qudits), recently proposed by Collins-Gisin-Linden-Massar-Popescu and Son-Lee-Kim. Taking an alternative approach, called the quantum-to-classical approach, we derive a series of Bell inequalities for qudits that satisfy the criterion as for the qubits. In the derivation each d-dimensional subsystem is assumed to be measured by one of d possible measurements with d being a prime integer. By applying to two qubits (d=2), we find that a derived inequality is reduced to the Clauser-Horne-Shimony-Holt inequality when the degree of nonlocality is optimized over all the possible states and local observables. Further applying to two and three qutrits (d=3), we find Bell inequalities that are violated for the three-dimensionally entangled states but are not violated by any two-dimensionally entangled states. In other words, the inequalities discriminate three-dimensional (3D) entanglement from two-dimensional (2D) entanglement and in this sense they are genuinely 3D. In addition, for the two qutrits we give a quantitative description of the relations among the three degrees of complementarity, entanglement and nonlocality. It is shown that the degree of complementarity jumps abruptly to very close to its maximum as nonlocality starts appearing. These characteristics imply that complementarity plays a more significant role in the present inequality compared with the previously proposed inequality.

  5. Detecting nonlocal Cooper pair entanglement by optical Bell inequality violation

    OpenAIRE

    Nigg, Simon E.; Tiwari, Rakesh P.; Walter, Stefan; Schmidt, Thomas L.

    2014-01-01

    Based on the Bardeen Cooper Schrieffer (BCS) theory of superconductivity, the coherent splitting of Cooper pairs from a superconductor to two spatially separated quantum dots has been predicted to generate nonlocal pairs of entangled electrons. In order to test this hypothesis, we propose a scheme to transfer the spin state of a split Cooper pair onto the polarization state of a pair of optical photons. We show that the produced photon pairs can be used to violate a Bell inequality, unambiguo...

  6. Secondary bifurcation for a nonlocal Allen-Cahn equation

    Science.gov (United States)

    Kuto, Kousuke; Mori, Tatsuki; Tsujikawa, Tohru; Yotsutani, Shoji

    2017-09-01

    This paper studies the Neumann problem of a nonlocal Allen-Cahn equation in an interval. A main result finds a symmetry breaking (secondary) bifurcation point on the bifurcation curve of solutions with odd-symmetry. Our proof is based on a level set analysis for the associated integral map. A method using the complete elliptic integrals proves the uniqueness of secondary bifurcation point. We also show some numerical simulations concerning the global bifurcation structure.

  7. Nonlocal symmetry breaking in Kaluza-Klein theories.

    Science.gov (United States)

    Masiero, A; Serone, M; Scrucca, C A; Silvestrini, L

    2001-12-17

    Scherk-Schwarz gauge symmetry breaking of a D-dimensional field theory model compactified on a circle is analyzed. It is explicitly shown that forbidden couplings in the unbroken theory appear in the one-loop effective action only in a nonlocal way, implying that they are finite at all orders in perturbation theory. This result can be understood as a consequence of the local gauge symmetry, but it holds true also in the global limit.

  8. Nonlocal Intuition: Replication and Paired-subjects Enhancement Effects

    Science.gov (United States)

    Mirzaei, Maryam; Zali, Mohammad Reza

    2014-01-01

    This article reports the results of a study of repeat entrepreneurs in Tehran, Iran, in which nonlocal intuition was investigated in a replication and extension of experiment using measures of heart rate variability (HRV). Nonlocal intuition is the perception of information about a distant or future event by the body's psychophysiological systems, which is not based on reason or memories of prior experience. This study follows up on the McCraty, Radin, and Bradley studies, which found evidence of nonlocal intuition. We used Radin's experimental protocol, with the addition of HRV measures as in the McCraty studies involving computer administration of a random sequence of calm and emotional pictures as the stimulus, and conducted two experiments on mutually exclusive samples—the first on a group of single participants (N=15) and the second on a group of co-participant pairs (N=30)—to investigate the question of the “amplification” of intuition effects by social connection. Each experiment was conducted over 45 trials while heart rate rhythm activity was recorded continuously. Results, using random permutation analysis, a statistically conservative procedure, show significant pre-stimulus results—that is, for the period before the computer had randomly selected the picture stimulus—for both experiments. Moreover, while significant separation between the emotional and calm HRV curves was observed in the single-participant experiment, an even larger separation was apparent for the experiment on co-participant pairs; the difference between the two groups was also significant. Overall, the results of the single-participant experiment confirm previous finding: that electrophysiological measures, especially changes in the heart rhythm, can detect intuitive foreknowledge. This result is notable because it constitutes cross-cultural corroboration in a non-Western context—namely, Iran. In addition, the results for co-participant pairs offer new evidence on the

  9. Characteristics of the chiral phase transition in nonlocal quark models

    International Nuclear Information System (INIS)

    Gomez Dumm, D. Gomez; Scoccola, N.N.

    2005-01-01

    The characteristics of the chiral phase transition are analyzed within the framework of chiral quark models with nonlocal interactions in the mean-field approximation. In the chiral limit, we develop a semianalytic framework that allows us to explicitly determine the phase transition curve, the position of the critical points, some relevant critical exponents, etc. For the case of finite current quark masses, we show the behavior of various thermodynamical and chiral response functions across the phase transition

  10. Ground state solutions for non-local fractional Schrodinger equations

    Directory of Open Access Journals (Sweden)

    Yang Pu

    2015-08-01

    Full Text Available In this article, we study a time-independent fractional Schrodinger equation with non-local (regional diffusion $$ (-\\Delta^{\\alpha}_{\\rho}u + V(xu = f(x,u \\quad \\text{in }\\mathbb{R}^{N}, $$ where $\\alpha \\in (0,1$, $N > 2\\alpha$. We establish the existence of a non-negative ground state solution by variational methods.

  11. Non-local gravity with a Weyl-square term

    CERN Document Server

    Cusin, Giulia; Maggiore, Michele; Mancarella, Michele

    2016-01-01

    Recent work has shown that modifications of General Relativity based on the addition of a non-local term $R\\,\\Box^{-2}R$ produce a dynamical model of dark energy, which is cosmologically viable both at the background level and at the level of cosmological perturbations. We explore a more general class of models based on the addition of terms proportional to $R_{\\mu\

  12. Nonlocal Symmetries and Exact Solutions for PIB Equation

    Science.gov (United States)

    Xin, Xiang-Peng; Miao, Qian; Chen, Yong

    2012-09-01

    In this paper, the symmetry group of the (2+1)-dimensional Painlevé integrable Burgers (PIB) equations is studied by means of the classical symmetry method. Ignoring the discussion of the infinite-dimensional subalgebra, we construct an optimal system of one-dimensional group invariant solutions. Furthermore, by using the conservation laws of the reduced equations, we obtain nonlocal symmetries and exact solutions of the PIB equations.

  13. Non-local flow effects on bedform dynamics

    Science.gov (United States)

    Perron, J. Taylor; Kao, Justin; Myrow, Paul

    2013-04-01

    Bedform patterns are sensitive recorders of feedbacks among bed topography, fluid flow, and sediment transport. Some of the most important feedbacks are local. For example, evolution models based on simple flow parameterizations that only incorporate local bed height can reproduce some of the essential features of bedform evolution, including bedform growth and migration. However, non-local effects can also be critically important. For example, field and laboratory measurements have shown that the spacing of most sand ripples generated by wave-driven oscillatory flows is linearly proportional to the amplitude of the flow oscillation, implying that fluid stress and sediment transport at a given location depend on upstream features that perturb the flow. A model that fully captures the coupling of flow and bedform evolution must include such effects, but it is not clear how detailed the description of the flow must be to reproduce the most important aspects of bedform evolution. To account for the most significant non-local flow effects without resorting to a coupled hydrodynamic model, we propose an approximation in which the bed shear stress is expressed as a convolution of the bed topography with a kernel that includes both local effects, such as acceleration over bumps, and non-local effects, such as flow separation and re-attachment. Two-dimensional flow simulations demonstrate that a single, generic kernel gives a good approximation of shear stress over a wide range of bed profiles under oscillatory and some combined flows. Incorporating this approximation into a simple bedform evolution model, we show that non-local effects are required to reproduce the characteristic transient patterns that emerge as wave ripples respond to changes in the flow, which we have documented with time-lapse imagery of laboratory wave tank experiments. We then show how this result informs interpretations of two-dimensional wave ripple patterns preserved in the geologic record.

  14. Maxwell-Garnett effective medium theory: Quantum nonlocal effects

    Energy Technology Data Exchange (ETDEWEB)

    Moradi, Afshin, E-mail: a.moradi@kut.ac.ir [Department of Engineering Physics, Kermanshah University of Technology, Kermanshah (Iran, Islamic Republic of)

    2015-04-15

    We develop the Maxwell-Garnett theory for the effective medium approximation of composite materials with metallic nanoparticles by taking into account the quantum spatial dispersion effects in dielectric response of nanoparticles. We derive a quantum nonlocal generalization of the standard Maxwell-Garnett formula, by means the linearized quantum hydrodynamic theory in conjunction with the Poisson equation as well as the appropriate additional quantum boundary conditions.

  15. Non-local deformation of a supersymmetric field theory

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Qin [National University of Singapore, Department of Physics, Singapore (Singapore); Faizal, Mir [University of Lethbridge, Department of Physics and Astronomy, Lethbridge (Canada); University of British Columbia - Okanagan, Irving K. Barber School of Arts and Sciences, Kelowna, BC (Canada); Shah, Mushtaq B.; Ganai, Prince A. [National Institute of Technology, Department of Physics, Srinagar, Kashmir (India); Bhat, Anha [National Institute of Technology, Department of Metallurgical and Materials Engineering, Srinagar (India); Zaz, Zaid [University of Kashmir, Department of Electronics and Communication Engineering, Srinagar, Kashmir (India); Masood, Syed; Raza, Jamil; Irfan, Raja Muhammad [International Islamic University, Department of Physics, Islamabad (Pakistan)

    2017-09-15

    In this paper, we will analyze a supersymmetric field theory deformed by generalized uncertainty principle and Lifshitz scaling. It will be observed that this deformed supersymmetric field theory contains non-local fractional derivative terms. In order to construct such a deformed N = 1 supersymmetric theory, a harmonic extension of functions will be used. However, the supersymmetry will only be preserved for a free theory and will be broken by the inclusion of interaction terms. (orig.)

  16. Non-local Thirring model at finite temperature

    Energy Technology Data Exchange (ETDEWEB)

    Manias, M.V.; Naon, C.M.; Trobo, M.L. [La Plata Univ. Nacional (Argentina). Dept. de Fisica]|[Consejo Nacional de Investigaciones Cientificas y Tecnicas (Argentina)

    1998-08-17

    We extend a recently proposed non-local and non-covariant version of the Thirring model to the finite-temperature case. We obtain a completely bosonized expression for the partition function, describing the thermodynamics of the collective modes which are the underlying excitations of this system. From this result we derive closed formulae for the free-energy, specific-heat, two-point correlation functions and momentum distribution, as functionals of electron-electron coupling potentials. (orig.) 15 refs.

  17. Somatic motility and hair bundle mechanics, are both necessary for cochlear amplification?

    Science.gov (United States)

    Peng, Anthony W; Ricci, Anthony J

    2011-03-01

    Hearing organs have evolved to detect sounds across several orders of magnitude of both intensity and frequency. Detection limits are at the atomic level despite the energy associated with sound being limited thermodynamically. Several mechanisms have evolved to account for the remarkable frequency selectivity, dynamic range, and sensitivity of these various hearing organs, together termed the active process or cochlear amplifier. Similarities between hearing organs of disparate species provides insight into the factors driving the development of the cochlear amplifier. These properties include: a tonotopic map, the emergence of a two hair cell system, the separation of efferent and afferent innervations, the role of the tectorial membrane, and the shift from intrinsic tuning and amplification to a more end organ driven process. Two major contributors to the active process are hair bundle mechanics and outer hair cell electromotility, the former present in all hair cell organs tested, the latter only present in mammalian cochlear outer hair cells. Both of these processes have advantages and disadvantages, and how these processes interact to generate the active process in the mammalian system is highly disputed. A hypothesis is put forth suggesting that hair bundle mechanics provides amplification and filtering in most hair cells, while in mammalian cochlea, outer hair cell motility provides the amplification on a cycle by cycle basis driven by the hair bundle that provides frequency selectivity (in concert with the tectorial membrane) and compressive nonlinearity. Separating components of the active process may provide additional sites for regulation of this process. Copyright © 2010 Elsevier B.V. All rights reserved.

  18. Wave instability induced by nonlocal spatial coupling in a model of the light-sensitive Belousov-Zhabotinsky reaction

    Science.gov (United States)

    Nicola, Ernesto M.; Bär, Markus; Engel, Harald

    2006-06-01

    We study spatiotemporal patterns resulting from instabilities induced by nonlocal spatial coupling in the Oregonator model of the light-sensitive Belousov-Zhabotinsky reaction. In this system, nonlocal coupling can be externally imposed by means of an optical feedback loop which links the intensity of locally applied illumination with the activity in a certain vicinity of a particular point weighted by a given coupling function. This effect is included in the three-variable Oregonator model by an additional integral term in the photochemically induced bromide flow. A linear stability analysis of this modified Oregonator model predicts that wave and Turing instabilities of the homogeneous steady state can be induced for experimentally realistic parameter values. In particular, we find that a long-range inhibition in the optical feedback leads to a Turing instability, while a long-range activation induces wave patterns. Using a weakly nonlinear analysis, we derive amplitude equations for the wave instability which are valid close to the instability threshold. Therein, we find that the wave instability occurs supercritically or subcritically and that traveling waves are preferred over standing waves. The results of the theoretical analysis are in good agreement with numerical simulations of the model near the wave instability threshold. For larger distances from threshold, a secondary breathing instability is found for traveling waves.

  19. Subquantum nonlocal correlations induced by the background random field

    International Nuclear Information System (INIS)

    Khrennikov, Andrei

    2011-01-01

    We developed a purely field model of microphenomena-prequantum classical statistical field theory (PCSFT). This model not only reproduces important probabilistic predictions of quantum mechanics (QM) including correlations for entangled systems, but also gives a possibility to go beyond QM, i.e. to make predictions of phenomena that could be observed at the subquantum level. In this paper, we discuss one such prediction-the existence of nonlocal correlations between prequantum random fields corresponding to all quantum systems. (And by PCSFT, quantum systems are represented by classical Gaussian random fields and quantum observables by quadratic forms of these fields.) The source of these correlations is the common background field. Thus all prequantum random fields are 'entangled', but in the sense of classical signal theory. On the one hand, PCSFT demystifies quantum nonlocality by reducing it to nonlocal classical correlations based on the common random background. On the other hand, it demonstrates total generality of such correlations. They exist even for distinguishable quantum systems in factorizable states (by PCSFT terminology-for Gaussian random fields with covariance operators corresponding to factorizable quantum states).

  20. Image fusion via nonlocal sparse K-SVD dictionary learning.

    Science.gov (United States)

    Li, Ying; Li, Fangyi; Bai, Bendu; Shen, Qiang

    2016-03-01

    Image fusion aims to merge two or more images captured via various sensors of the same scene to construct a more informative image by integrating their details. Generally, such integration is achieved through the manipulation of the representations of the images concerned. Sparse representation plays an important role in the effective description of images, offering a great potential in a variety of image processing tasks, including image fusion. Supported by sparse representation, in this paper, an approach for image fusion by the use of a novel dictionary learning scheme is proposed. The nonlocal self-similarity property of the images is exploited, not only at the stage of learning the underlying description dictionary but during the process of image fusion. In particular, the property of nonlocal self-similarity is combined with the traditional sparse dictionary. This results in an improved learned dictionary, hereafter referred to as the nonlocal sparse K-SVD dictionary (where K-SVD stands for the K times singular value decomposition that is commonly used in the literature), and abbreviated to NL_SK_SVD. The performance of the NL_SK_SVD dictionary is applied for image fusion using simultaneous orthogonal matching pursuit. The proposed approach is evaluated with different types of images, and compared with a number of alternative image fusion techniques. The resultant superior fused images using the present approach demonstrates the efficacy of the NL_SK_SVD dictionary in sparse image representation.

  1. Optimizing plasmon-enhanced fluorescence with nonlocal metallic nanospheres

    DEFF Research Database (Denmark)

    Tserkezis, Christos; Stefanou, Nikolaos; Wubs, Martijn

    The fluorescence signal η of molecules coupled to plasmonic nanoparticles (NPs) is optimized through extended simulations, taking the metal nonlocal optical response fully into account. Solid Au and Ag nanospheres, as well as SiO2/Au(Ag) core/shell NPs (of total radius R), are engineered to maxim......The fluorescence signal η of molecules coupled to plasmonic nanoparticles (NPs) is optimized through extended simulations, taking the metal nonlocal optical response fully into account. Solid Au and Ag nanospheres, as well as SiO2/Au(Ag) core/shell NPs (of total radius R), are engineered......, through the recent Generalized Nonlocal Optical Response (GNOR) theory, the concurrent contribution of modal shifts and nonradiative losses, together with a reduced emitter excitation rate due to the decreased field intensity, lead always to a strong reduction of fluorescence (see Fig. 1). Finally, we...... identify situations where the common, intuitive recipe of tuning the NP modes to match λem can in fact lead to strong fluorescence quenching, instead of the anticipated enhancement. Our results highlight the necessity for careful modeling and design of plasmon-field-enhancement based applications....

  2. Critical thresholds in flocking hydrodynamics with non-local alignment.

    Science.gov (United States)

    Tadmor, Eitan; Tan, Changhui

    2014-11-13

    We study the large-time behaviour of Eulerian systems augmented with non-local alignment. Such systems arise as hydrodynamic descriptions of agent-based models for self-organized dynamics, e.g. Cucker & Smale (2007 IEEE Trans. Autom. Control 52, 852-862. (doi:10.1109/TAC.2007.895842)) and Motsch & Tadmor (2011 J. Stat. Phys. 144, 923-947. (doi:10.1007/s10955-011-0285-9)) models. We prove that, in analogy with the agent-based models, the presence of non-local alignment enforces strong solutions to self-organize into a macroscopic flock. This then raises the question of existence of such strong solutions. We address this question in one- and two-dimensional set-ups, proving global regularity for subcritical initial data. Indeed, we show that there exist critical thresholds in the phase space of the initial configuration which dictate the global regularity versus a finite-time blow-up. In particular, we explore the regularity of non-local alignment in the presence of vacuum. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  3. Nonlocal Regularized Algebraic Reconstruction Techniques for MRI: An Experimental Study

    Directory of Open Access Journals (Sweden)

    Xin Li

    2013-01-01

    Full Text Available We attempt to revitalize researchers' interest in algebraic reconstruction techniques (ART by expanding their capabilities and demonstrating their potential in speeding up the process of MRI acquisition. Using a continuous-to-discrete model, we experimentally study the application of ART into MRI reconstruction which unifies previous nonuniform-fast-Fourier-transform- (NUFFT- based and gridding-based approaches. Under the framework of ART, we advocate the use of nonlocal regularization techniques which are leveraged from our previous research on modeling photographic images. It is experimentally shown that nonlocal regularization ART (NR-ART can often outperform their local counterparts in terms of both subjective and objective qualities of reconstructed images. On one real-world k-space data set, we find that nonlocal regularization can achieve satisfactory reconstruction from as few as one-third of samples. We also address an issue related to image reconstruction from real-world k-space data but overlooked in the open literature: the consistency of reconstructed images across different resolutions. A resolution-consistent extension of NR-ART is developed and shown to effectively suppress the artifacts arising from frequency extrapolation. Both source codes and experimental results of this work are made fully reproducible.

  4. Nonlinear optimization

    CERN Document Server

    Ruszczynski, Andrzej

    2011-01-01

    Optimization is one of the most important areas of modern applied mathematics, with applications in fields from engineering and economics to finance, statistics, management science, and medicine. While many books have addressed its various aspects, Nonlinear Optimization is the first comprehensive treatment that will allow graduate students and researchers to understand its modern ideas, principles, and methods within a reasonable time, but without sacrificing mathematical precision. Andrzej Ruszczynski, a leading expert in the optimization of nonlinear stochastic systems, integrates the theory and the methods of nonlinear optimization in a unified, clear, and mathematically rigorous fashion, with detailed and easy-to-follow proofs illustrated by numerous examples and figures. The book covers convex analysis, the theory of optimality conditions, duality theory, and numerical methods for solving unconstrained and constrained optimization problems. It addresses not only classical material but also modern top...

  5. CSF gusher in cochlear implantation: The risk of missing CT evidence of a cochlear base defect in the presence of otherwise normal cochlear anatomy.

    Science.gov (United States)

    Cabbarzade, Cavid; Sennaroglu, Levent; Süslü, Nilda

    2015-07-01

    Intraoperative cerebrospinal fluid (CSF) leakages from the cochleostomy site - known as gushers - are a serious complication of cochlear implantation surgery in cases of congenital deafness. They occur as the result of abnormal communication between CSF in the internal auditory canal and perilymph in the cochlea. Gushers are well recognized as occurring in a proportion of cases in which there is a clearly visible congenital malformation of the cochlea. In this report, we describe two cases in which pre-operative computed tomography (CT) scanning of the cochlea was initially reported as normal but gushers occurred during cochlear implant surgery. In both cases, more detailed review of the CT scans (peroperatively in the first case, pre-operatively in the second case) showed a defect at the cochlear base, in the absence of any other cochlear malformation. The aim of this paper is to draw attention to the risk of missing this abnormality and to encourage careful inspection of the cochlear base on CT scans in all cases, even when the rest of the cochlear appears normal.

  6. Nonlocal integrable PDEs from hierarchies of symmetry laws: The example of Pohlmeyer-Lund-Regge equation and its reflectionless potential solutions

    Science.gov (United States)

    Demontis, F.; Ortenzi, G.; van der Mee, C.

    2018-04-01

    By following the ideas presented by Fukumoto and Miyajima in Fukumoto and Miyajima (1996) we derive a generalized method for constructing integrable nonlocal equations starting from any bi-Hamiltonian hierarchy supplied with a recursion operator. This construction provides the right framework for the application of the full machinery of the inverse scattering transform. We pay attention to the Pohlmeyer-Lund-Regge equation coming from the nonlinear Schrödinger hierarchy and construct the formula for the reflectionless potential solutions which are generalizations of multi-solitons. Some explicit examples are discussed.

  7. Racemic alkaloids from the fungus Ganoderma cochlear.

    Science.gov (United States)

    Wang, Xin-Long; Dou, Man; Luo, Qi; Cheng, Li-Zhi; Yan, Yong-Ming; Li, Rong-Tao; Cheng, Yong-Xian

    2017-01-01

    Seven pairs of new alkaloid enantiomers, ganocochlearines C-I (1, 3-8), and three pairs of known alkaloids were isolated from the fruiting bodies of Ganoderma cochlear. The chemical structures of new compounds were elucidated on the basis of 1D and 2D NMR data. The absolute configurations of compounds 1, 3-10 were assigned by ECD calculations. Biological activities of these isolates against renal fibrosis were accessed in rat normal or diseased renal interstitial fibroblast cells. Importantly, the plausible biosynthetic pathway for this class of alkaloids was originally proposed. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. [Cochlear Implant - State of the Art].

    Science.gov (United States)

    Lenarz, Thomas

    2017-04-01

    Cochlear implants are the treatment of choice for the auditory rehabilitation of patients with sensory deafness. They restore the missing function of inner hair cells by transforming the acoustic signal into electrical stimuli for activation of auditory nerve fibers. Due to the very fast technology development cochlear implants provide open-set speech understanding in the majority of patients including the use of the telephone. Children can achieve a near to normal speech and language development provided their deafness is detected early after onset and implantation is performed quickly thereafter. The diagnostic procedure as well as the surgical techniques have been standardized and can be adapted to the individual anatomical and physiological needs both in children and adults. Special cases such as cochlear obliteration or malformations can be addressed. Device failures and medical complications might require special measures and reimplantation which can be done in most cases in a straight forward way. Technology upgrades count for better performance.Future developments will focus on better electrode nerve interfaces by improving electrode technology. An increased number of electrical contacts as well as the biological treatment with regeneration of the dendrides growing onto the electrode will increase the number of electrical channels. This will give room for improved speech coding strategies in order to create the bionic ear, i. e. to restore the process of natural hearing by means of technology. The robot assisted surgery will allow for high precision surgery and reliable hearing preservation. Biological therapies will support the bionic ear. Methods are biohybrid electrodes which are coded by stem cells transplanted into the inner ear to enhance autoproduction of neurotrophins. Local drug delivery will focus on suppression of trauma reaction and local regeneration. Gene therapy by nanoparticles will hopefully lead to the preservation of residual hearing in

  9. Cochlear implant - state of the art.

    Science.gov (United States)

    Lenarz, Thomas

    2017-01-01

    Cochlear implants are the treatment of choice for auditory rehabilitation of patients with sensory deafness. They restore the missing function of inner hair cells by transforming the acoustic signal into electrical stimuli for activation of auditory nerve fibers. Due to the very fast technology development, cochlear implants provide open-set speech understanding in the majority of patients including the use of the telephone. Children can achieve a near to normal speech and language development provided their deafness is detected early after onset and implantation is performed quickly thereafter. The diagnostic procedure as well as the surgical technique have been standardized and can be adapted to the individual anatomical and physiological needs both in children and adults. Special cases such as cochlear obliteration might require special measures and re-implantation, which can be done in most cases in a straight forward way. Technology upgrades count for better performance. Future developments will focus on better electrode-nerve interfaces by improving electrode technology. An increased number of electrical contacts as well as the biological treatment with regeneration of the dendrites growing onto the electrode will increase the number of electrical channels. This will give room for improved speech coding strategies in order to create the bionic ear, i.e. to restore the process of natural hearing by means of technology. The robot-assisted surgery will allow for high precision surgery and reliable hearing preservation. Biological therapies will support the bionic ear. Methods are bio-hybrid electrodes, which are coded by stem cells transplanted into the inner ear to enhance auto-production of neurotrophins. Local drug delivery will focus on suppression of trauma reaction and local regeneration. Gene therapy by nanoparticles will hopefully lead to the preservation of residual hearing in patients being affected by genetic hearing loss. Overall the cochlear implant

  10. Cochlear implant – state of the art

    Science.gov (United States)

    Lenarz, Thomas

    2018-01-01

    Cochlear implants are the treatment of choice for auditory rehabilitation of patients with sensory deafness. They restore the missing function of inner hair cells by transforming the acoustic signal into electrical stimuli for activation of auditory nerve fibers. Due to the very fast technology development, cochlear implants provide open-set speech understanding in the majority of patients including the use of the telephone. Children can achieve a near to normal speech and language development provided their deafness is detected early after onset and implantation is performed quickly thereafter. The diagnostic procedure as well as the surgical technique have been standardized and can be adapted to the individual anatomical and physiological needs both in children and adults. Special cases such as cochlear obliteration might require special measures and re-implantation, which can be done in most cases in a straight forward way. Technology upgrades count for better performance. Future developments will focus on better electrode-nerve interfaces by improving electrode technology. An increased number of electrical contacts as well as the biological treatment with regeneration of the dendrites growing onto the electrode will increase the number of electrical channels. This will give room for improved speech coding strategies in order to create the bionic ear, i.e. to restore the process of natural hearing by means of technology. The robot-assisted surgery will allow for high precision surgery and reliable hearing preservation. Biological therapies will support the bionic ear. Methods are bio-hybrid electrodes, which are coded by stem cells transplanted into the inner ear to enhance auto-production of neurotrophins. Local drug delivery will focus on suppression of trauma reaction and local regeneration. Gene therapy by nanoparticles will hopefully lead to the preservation of residual hearing in patients being affected by genetic hearing loss. Overall the cochlear implant

  11. Microflora of Retained Intracochlear Electrodes from Infected Cochlear Implants.

    Science.gov (United States)

    Varadarajan, Varun V; Dirain, Carolyn O; Antonelli, Patrick J

    2017-07-01

    Objectives Cochlear implant infections may be refractory to medical management and require device removal with subsequent reimplantation. During device removal, the intracochlear electrode array is commonly left in place to prevent obliteration of the cochlear lumen. If the electrode is colonized with pathogens, this risks contaminating the replacement implant. In this study, we compare the microorganisms detected on infected cochlear implants against those on the retained electrode using culture and microbial gene-sequencing techniques. Study Design Prospective single-cohort study. Setting Tertiary medical center. Subjects and Methods Six patients with refractory cochlear implant infections had the receiver-stimulator and extracochlear electrode removed to facilitate treatment of the infection. The intracochlear electrode was removed at (delayed) reimplantation. Implant specimens were analyzed by microbial culture and 16S DNA gene sequencing. Results Staphylococcus aureus was the organism most commonly identified. None of the 6 patients' intracochlear electrodes yielded microbes by culture. Two intracochlear electrodes revealed bacterial species, and 1 revealed fungal species by gene sequencing. There was no correlation between the microbes on the infected extracochlear implants and the retained intracochlear electrodes. All subjects underwent reimplantation after resolution of their infections. One of 6 subjects developed a second infection after reimplantation, with S aureus in the primary and secondary infections. Conclusions The intracochlear electrodes of infected cochlear implants carry a low microbial burden. Preserving intracochlear electrodes upon removal of infected cochlear implants appears to carry a low risk of contaminating a replacement cochlear implant.

  12. Music mixing preferences of cochlear implant recipients: a pilot study.

    Science.gov (United States)

    Buyens, Wim; van Dijk, Bas; Moonen, Marc; Wouters, Jan

    2014-05-01

    Music perception and appraisal are generally poor in cochlear implant recipients. Simple musical structures, lyrics that are easy to follow, and clear rhythm/beat have been reported among the top factors to enhance music enjoyment. The present study investigated the preference for modified relative instrument levels in music with normal-hearing and cochlear implant subjects. In experiment 1, test subjects were given a mixing console and multi-track recordings to determine their most enjoyable audio mix. In experiment 2, a preference rating experiment based on the preferred relative level settings in experiment 1 was performed. Experiment 1 was performed with four postlingually deafened cochlear implant subjects, experiment 2 with ten normal-hearing and ten cochlear implant subjects. A significant difference in preference rating was found between normal-hearing and cochlear implant subjects. The latter preferred an audio mix with larger vocals-to-instruments ratio. In addition, given an audio mix with clear vocals and attenuated instruments, cochlear implant subjects preferred the bass/drum track to be louder than the other instrument tracks. The original audio mix in real-world music might not be suitable for cochlear implant recipients. Modifying the relative instrument level settings potentially improves music enjoyment.

  13. Chronic Conductive Hearing Loss Leads to Cochlear Degeneration.

    Science.gov (United States)

    Liberman, M Charles; Liberman, Leslie D; Maison, Stéphane F

    2015-01-01

    Synapses between cochlear nerve terminals and hair cells are the most vulnerable elements in the inner ear in both noise-induced and age-related hearing loss, and this neuropathy is exacerbated in the absence of efferent feedback from the olivocochlear bundle. If age-related loss is dominated by a lifetime of exposure to environmental sounds, reduction of acoustic drive to the inner ear might improve cochlear preservation throughout life. To test this, we removed the tympanic membrane unilaterally in one group of young adult mice, removed the olivocochlear bundle in another group and compared their cochlear function and innervation to age-matched controls one year later. Results showed that tympanic membrane removal, and the associated threshold elevation, was counterproductive: cochlear efferent innervation was dramatically reduced, especially the lateral olivocochlear terminals to the inner hair cell area, and there was a corresponding reduction in the number of cochlear nerve synapses. This loss led to a decrease in the amplitude of the suprathreshold cochlear neural responses. Similar results were seen in two cases with conductive hearing loss due to chronic otitis media. Outer hair cell death was increased only in ears lacking medial olivocochlear innervation following olivocochlear bundle cuts. Results suggest the novel ideas that 1) the olivocochlear efferent pathway has a dramatic use-dependent plasticity even in the adult ear and 2) a component of the lingering auditory processing disorder seen in humans after persistent middle-ear infections is cochlear in origin.

  14. Betahistine exerts a dose-dependent effect on cochlear stria vascularis blood flow in guinea pigs in vivo.

    Directory of Open Access Journals (Sweden)

    Fritz Ihler

    Full Text Available Betahistine is a histamine H(1-receptor agonist and H(3-receptor antagonist that is administered to treat Menière's disease. Despite widespread use, its pharmacological mode of action has not been entirely elucidated. This study investigated the effect of betahistine on guinea pigs at dosages corresponding to clinically used doses for cochlear microcirculation.Thirty healthy Dunkin-Hartley guinea pigs were randomly assigned to five groups to receive betahistine dihydrochloride in a dose of 1,000 mg/kg b. w. (milligram per kilogram body weight, 0.100 mg/kg b. w., 0.010 mg/kg b. w., 0.001 mg/kg b. w. in NaCl 0.9% or NaCl 0.9% alone as placebo. Cochlear blood flow and mean arterial pressure were continuously monitored by intravital fluorescence microscopy and invasive blood pressure measurements 3 minutes before and 15 minutes after administration of betahistine.When betahistine was administered in a dose of 1.000 mg/kg b. w. cochlear blood flow was increased to a peak value of 1.340 arbitrary units (SD: 0.246; range: 0.933-1.546 arb. units compared to baseline (p<0.05; Two Way Repeated Measures ANOVA/Bonferroni t-test. The lowest dosage of 0.001 mg/kg b. w. betahistine or NaCl 0.9% had the same effect as placebo. Nonlinear regression revealed that there was a sigmoid correlation between increase in blood flow and dosages.Betahistine has a dose-dependent effect on the increase of blood flow in cochlear capillaries. The effects of the dosage range of betahistine on cochlear microcirculation corresponded well to clinically used single dosages to treat Menière's disease. Our data suggest that the improved effects of higher doses of betahistine in the treatment of Menière's disease might be due to a corresponding increase of cochlear blood flow.

  15. Conservation Laws and Nonlocally Related Systems of Two-Dimensional Boundary Layer Models

    Science.gov (United States)

    Naz, R.; Cheviakov, A. F.

    2017-10-01

    Local conservation laws, potential systems, and nonlocal conservation laws are systematically computed for three-equilibrium two-component boundary layer models that describe different physical situations: a plate flow, a flow parallel to the axis of a circular cylinder, and a radial jet striking a planar wall. First, local conservation laws of each model are computed using the direct method. For each of the three boundary layer models, two local conservation laws are found. The corresponding potential variables are introduced, and nonlocally related potential systems and subsystems are formed. Then nonlocal conservation laws are sought, arising as local conservation laws of nonlocally related systems. For each of the three physical models, similar nonlocal conservation laws arise. Further nonlocal variables that lead to further potential systems are considered. Trees of nonlocally related systems are constructed; their structure coincides for all three models. The three boundary layer models considered in this work provide rich and interesting examples of the construction of trees of nonlocally related systems. In particular, the trees involve spectral potential systems depending on a parameter; these spectral potential systems lead to nonlocal conservation laws. Moreover, potential variables that are not locally related on solution sets of some potential systems become local functions of each other on solution sets of other systems. The point symmetry analysis shows that the plate and radial jet flow models possess infinite-dimensional Lie algebras of point symmetries, whereas the Lie algebra of point symmetries for the cylinder flow model is three-dimensional. The computation of nonlocal symmetries reveals none that arise for the original model equations, which is common for partial differential equations (PDE) systems without constitutive parameters or functions, but does reveal nonlocal symmetries for some nonlocally related PDE systems.

  16. A Morphing framework to couple non-local and local anisotropic continua

    KAUST Repository

    Azdoud, Yan

    2013-05-01

    In this article, we develop a method to couple anisotropic local continua with anisotropic non-local continua with central long-range forces. First, we describe anisotropic non-local models based on spherical harmonic descriptions. We then derive compatible classic continuum models. Finally, we apply the morphing method to these anisotropic non-local models and present three-dimensional numerical examples to validate the efficiency of the technique. © 2013 Elsevier Ltd. All rights reserved.

  17. A space-jump derivation for non-local models of cell-cell adhesion and non-local chemotaxis.

    Science.gov (United States)

    Buttenschön, Andreas; Hillen, Thomas; Gerisch, Alf; Painter, Kevin J

    2018-01-01

    Cellular adhesion provides one of the fundamental forms of biological interaction between cells and their surroundings, yet the continuum modelling of cellular adhesion has remained mathematically challenging. In 2006, Armstrong et al. proposed a mathematical model in the form of an integro-partial differential equation. Although successful in applications, a derivation from an underlying stochastic random walk has remained elusive. In this work we develop a framework by which non-local models can be derived from a space-jump process. We show how the notions of motility and a cell polarization vector can be naturally included. With this derivation we are able to include microscopic biological properties into the model. We show that particular choices yield the original Armstrong model, while others lead to more general models, including a doubly non-local adhesion model and non-local chemotaxis models. Finally, we use random walk simulations to confirm that the corresponding continuum model represents the mean field behaviour of the stochastic random walk.

  18. On the stability and compressive nonlinearity of a physiologically based model of the cochlea

    Energy Technology Data Exchange (ETDEWEB)

    Nankali, Amir [Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan (United States); Grosh, Karl [Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan (United States); Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan (United States)

    2015-12-31

    Hearing relies on a series of coupled electrical, acoustical (fluidic) and mechanical interactions inside the cochlea that enable sound processing. A positive feedback mechanism within the cochlea, called the cochlear amplifier, provides amplitude and frequency selectivity in the mammalian auditory system. The cochlear amplifier and stability are studied using a nonlinear, micromechanical model of the Organ of Corti (OoC) coupled to the electrical potentials in the cochlear ducts. It is observed that the mechano-electrical transduction (MET) sensitivity and somatic motility of the outer hair cell (OHC), control the cochlear stability. Increasing MET sensitivity beyond a critical value, while electromechanical coupling coefficient is within a specific range, causes instability. We show that instability in this model is generated through a supercritical Hopf bifurcation. A reduced order model of the system is approximated and it is shown that the tectorial membrane (TM) transverse mode effect on the dynamics is significant while the radial mode can be simplified from the equations. The cochlear amplifier in this model exhibits good agreement with the experimental data. A comprehensive 3-dimensional model based on the cross sectional model is simulated and the results are compared. It is indicated that the global model qualitatively inherits some characteristics of the local model, but the longitudinal coupling along the cochlea shifts the stability boundary (i.e., Hopf bifurcation point) and enhances stability.

  19. Modulation of outer hair cell electromotility by cochlear supporting cells and gap junctions.

    Directory of Open Access Journals (Sweden)

    Ning Yu

    2009-11-01

    Full Text Available Outer hair cell (OHC or prestin-based electromotility is an active cochlear amplifier in the mammalian inner ear that can increase hearing sensitivity and frequency selectivity. In situ, Deiters supporting cells are well-coupled by gap junctions and constrain OHCs standing on the basilar membrane. Here, we report that both electrical and mechanical stimulations in Deiters cells (DCs can modulate OHC electromotility. There was no direct electrical conductance between the DCs and the OHCs. However, depolarization in DCs reduced OHC electromotility associated nonlinear capacitance (NLC and distortion products. Increase in the turgor pressure of DCs also shifted OHC NLC to the negative voltage direction. Destruction of the cytoskeleton in DCs or dissociation of the mechanical-coupling between DCs and OHCs abolished these effects, indicating the modulation through the cytoskeleton activation and DC-OHC mechanical coupling rather than via electric field potentials. We also found that changes in gap junctional coupling between DCs induced large membrane potential and current changes in the DCs and shifted OHC NLC. Uncoupling of gap junctions between DCs shifted NLC to the negative direction. These data indicate that DCs not only provide a physical scaffold to support OHCs but also can directly modulate OHC electromotility through the DC-OHC mechanical coupling. Our findings reveal a new mechanism of cochlear supporting cells and gap junctional coupling to modulate OHC electromotility and eventually hearing sensitivity in the inner ear.

  20. Waardenburg Syndrome: An Unusual Indication of Cochlear Implantation Experienced in 11 Patients.

    Science.gov (United States)

    Bayrak, Feda; Çatlı, Tolgahan; Atsal, Görkem; Tokat, Taşkın; Olgun, Levent

    2017-08-01

    The aim of this study was to present the surgical findings of children with Waardenburg syndrome (WS) and investigate speech development after cochlear implantation in this unique group of patients. A retrospective chart review of the patients diagnosed with WS and implanted between 1998 and 2015 was performed. Categories of auditory performance (CAP) test were used to assess the auditory skills of these patients. CAP is a nonlinear hierarchical scale used to rate a child's developing auditory abilities. Preoperative test results and intraoperative surgical findings of these patients have been presented. In total, 1835 cases were implanted a tour institution, and 1210 of these were children. Among these implantees, 11 were diagnosed with WS (0.59% of all implantees). Four of the 11 patients showed incomplete partition type 2bony labyrinth abnormality (Mondini deformity) and all patients showed intraoperative gusher during cochleostomy, which was subsided through routine interventions. No other complications occurred during surgery, and all patients showed satisfactory CAP results in the late postoperative period. Our experiences with cochlear implantation in patients with WS showed that the procedure is safe and effective in this group of patients. Surgeons should be aware of possible labyrinth malformations and intraoperative problems such as gusher in these patients. In long term, auditory performances may exhibit satisfactory results with optimal postoperative educational and supportive measures.

  1. Free vibrations analysis of carbon nanotubes resting on Winkler foundations based on nonlocal models

    Science.gov (United States)

    Rahmanian, M.; Torkaman-Asadi, M. A.; Firouz-Abadi, R. D.; Kouchakzadeh, M. A.

    2016-03-01

    In the present study, free vibrations of single walled carbon nanotubes (SWCNT) on an elastic foundation is investigated by nonlocal theory of elasticity with both beam and shell models. The nonlocal boundary conditions are derived explicitly and effectiveness of nonlocal parameter appearing in nonlocal boundary conditions is studied. Also it is demonstrated that the beam model is comparatively incapable of capturing size effects while shell model captures size effects more precisely. Moreover, the effects of some parameters such as mechanical properties, foundation stiffness, length and radius ratios on the natural frequencies are studied and some conclusions are drawn.

  2. Localized excitations in discrete nonlinear Schrodinger systems: Effects of nonlocal dispersive interactions and noise

    DEFF Research Database (Denmark)

    Rasmussen, Kim; Christiansen, Peter Leth; Johansson, Magnus

    1998-01-01

    , s(cr), there is an interval of bistability where two stable stationary states exist at each excitation number. The bistability of on-site solitons may occur for dipole-dipole dispersive interaction (s = 3), while s(cr) for inter-sire solitons is close to 2.1. In the framework of the DNLS equation...

  3. The nonlocal boundary value problems for strongly singular higher-order nonlinear functional-differential equations

    Czech Academy of Sciences Publication Activity Database

    Mukhigulashvili, Sulkhan

    -, č. 35 (2015), s. 23-50 ISSN 1126-8042 Institutional support: RVO:67985840 Keywords : higher order functional differential equations * Dirichlet boundary value problem * strong singularity Subject RIV: BA - General Mathematics http://ijpam.uniud.it/online_issue/201535/03-Mukhigulashvili.pdf

  4. Finite Volume schemes on unstructured grids for non-local models: Application to the simulation of heat transport in plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Goudon, Thierry, E-mail: thierry.goudon@inria.fr [Team COFFEE, INRIA Sophia Antipolis Mediterranee (France); Labo. J.A. Dieudonne CNRS and Univ. Nice-Sophia Antipolis (UMR 7351), Parc Valrose, 06108 Nice cedex 02 (France); Parisot, Martin, E-mail: martin.parisot@gmail.com [Project-Team SIMPAF, INRIA Lille Nord Europe, Park Plazza, 40 avenue Halley, F-59650 Villeneuve d' Ascq cedex (France)

    2012-10-15

    In the so-called Spitzer-Haerm regime, equations of plasma physics reduce to a nonlinear parabolic equation for the electronic temperature. Coming back to the derivation of this limiting equation through hydrodynamic regime arguments, one is led to construct a hierarchy of models where the heat fluxes are defined through a non-local relation which can be reinterpreted as well by introducing coupled diffusion equations. We address the question of designing numerical methods to simulate these equations. The basic requirement for the scheme is to be asymptotically consistent with the Spitzer-Haerm regime. Furthermore, the constraints of physically realistic simulations make the use of unstructured meshes unavoidable. We develop a Finite Volume scheme, based on Vertex-Based discretization, which reaches these objectives. We discuss on numerical grounds the efficiency of the method, and the ability of the generalized models in capturing relevant phenomena missed by the asymptotic problem.

  5. A new fractional nonlocal model and its application in free vibration of Timoshenko and Euler-Bernoulli beams

    Science.gov (United States)

    Rahimi, Zaher; Sumelka, Wojciech; Yang, Xiao-Jun

    2017-11-01

    The application of fractional calculus in fractional models (FMs) makes them more flexible than integer models inasmuch they can conclude all of integer and non-integer operators. In other words FMs let us use more potential of mathematics to modeling physical phenomena due to the use of both integer and fractional operators to present a better modeling of problems, which makes them more flexible and powerful. In the present work, a new fractional nonlocal model has been proposed, which has a simple form and can be used in different problems due to the simple form of numerical solutions. Then the model has been used to govern equations of the motion of the Timoshenko beam theory (TBT) and Euler-Bernoulli beam theory (EBT). Next, free vibration of the Timoshenko and Euler-Bernoulli simply-supported (S-S) beam has been investigated. The Galerkin weighted residual method has been used to solve the non-linear governing equations.

  6. The Impact of Cochlear Implants and Aural Rehabilitation Program on Auditory Skills of Children with Cochlear Implant

    Directory of Open Access Journals (Sweden)

    Zahra Jeddi

    2013-04-01

    Full Text Available Objective: Aural rehabilitation program after a cochlear implant leads to improve the auditory performance of hearing impaired children. The present study aims to determine the effect of cochlear implants and aural rehabilitation program in the auditory development of children with cochlear implants (CI. Materials & Methods: This longitudinal descriptive-analytical study was conducted on 15 deaf children (m.a. 45.27 mo who received CI in the AmirAlam cochlear implant center between August 2010 and January 2011. Auditory skills of deaf children were assessed before they received CI, and also 2, 4, 6 and 8 months after implantation. Data was collected interview with parents of deaf children through Newsha developmental scale. After determining the developmental age, Pretest Developmental Rate, Intervention Efficiency Index and Proportional Change Index were calculated. One-way ANOVA and LSD post hoc tests were used for analysis of data. Results: There was a significant increase in Pretest Developmental Rate during the aural rehabilitation after a cochlear implantation (P<0.0001. There was a significant difference among the 4 follow up assessments of Intervention Efficiency Index (P<0.0001. There was also a significant difference among the 4 follow up assessments of proportional change index (P<0.0001. Conclusion: Aural rehabilitation program after a cochlear implant can accelerate the development of auditory skills of children with cochlear implants, which in turn results in promotion of acquired skills close to normal hearing peers

  7. Endoscopic cochlear implantation: Call for caution.

    Science.gov (United States)

    Tarabichi, Muaaz; Nazhat, Omar; Kassouma, Jamal; Najmi, Murtaza

    2016-03-01

    To assess whether transcanal endoscopic access to the basal turn of the cochlea for cochlear implantation is appropriate. Case series study. We reviewed 100 consecutive computed tomographic studies of the sinuses and temporal bone in our institution. We excluded studies that demonstrated evidence of congenital anomalies, chronic ear disease, or inadequate visualization of the cochlea. On axial sections, the angles of the basal turn of the cochlea and of the ear canal in reference to the sagittal plane were recorded as a function of age. Eighty-four studies were included and 16 were excluded. There was significant variability in the relationship between the ear canal and the basal turn of the cochlea in reference to the sagittal plane. A clear majority of images demonstrated the basal turn of the cochlea to align with a more posterior angle than that of the ear canal. The trajectory provided by posterior tympanotomy aligns more favorably with the basal turn of the cochlea than transcanal access. Endoscopic technique, primarily an ear canal intervention, may not be useful in cochlear implant surgery. 4. Laryngoscope, 126:689-692, 2016. © 2015 The American Laryngological, Rhinological and Otological Society, Inc.

  8. Hearing Preservation after Cochlear Implantation: UNICAMP Outcomes

    Directory of Open Access Journals (Sweden)

    Guilherme Machado de Carvalho

    2013-01-01

    Full Text Available Background. Electric-acoustic stimulation (EAS is an excellent choice for people with residual hearing in low frequencies but not high frequencies and who derive insufficient benefit from hearing aids. For EAS to be effective, subjects' residual hearing must be preserved during cochlear implant (CI surgery. Methods. We implanted 6 subjects with a CI. We used a special surgical technique and an electrode designed to be atraumatic. Subjects' rates of residual hearing preservation were measured 3 times postoperatively, lastly after at least a year of implant experience. Subjects' aided speech perception was tested pre- and postoperatively with a sentence test in quiet. Subjects' subjective responses assessed after a year of EAS or CI experience. Results. 4 subjects had total or partial residual hearing preservation; 2 subjects had total residual hearing loss. All subjects' hearing and speech perception benefited from cochlear implantation. CI diminished or eliminated tinnitus in all 4 subjects who had it preoperatively. 5 subjects reported great satisfaction with their new device. Conclusions. When we have more experience with our surgical technique we are confident we will be able to report increased rates of residual hearing preservation. Hopefully, our study will raise the profile of EAS in Brazil and Latin/South America.

  9. Balance in children following cochlear implantation.

    Science.gov (United States)

    Kelly, Andrew; Liu, Zhaobo; Leonard, Shanna; Toner, Fearghal; Adams, Mark; Toner, Joseph

    2018-01-01

    To assess the vestibular function of children who had unilateral and bilateral cochlear implants compared with a control group of otherwise healthy children who had not been implanted. Observational case-control study. Posturography was carried out in the form of a Modified Clinical Test of Sensory Interaction on Balance using a Wii Balance Board and the Vestio App on an iPod Touch. Thirty children in total were tested, 10 children in each cohort. Results in the form of root mean square calculations were available for each child. Results showed a significant difference in the vestibular function of implanted children and the non-implanted control group (P < 0.05). As expected, children in all groups had more difficulty maintaining posture with their eyes closed on a compliant surface (P < 0.05). Thirty per cent of children with bilateral and 10% with unilateral cochlear implants were unable to complete testing. Our study demonstrates posturography as an inexpensive, easily operated tool that can be used to assess paediatric vestibular function. It showed a significant difference between the control group and the implanted groups. Further work prompted by this study will include interval post-operative testing to more accurately assess the effect that implantation has on vestibular function.

  10. Cochlear implant simulator for surgical technique analysis

    Science.gov (United States)

    Turok, Rebecca L.; Labadie, Robert F.; Wanna, George B.; Dawant, Benoit M.; Noble, Jack H.

    2014-03-01

    Cochlear Implant (CI) surgery is a procedure in which an electrode array is inserted into the cochlea. The electrode array is used to stimulate auditory nerve fibers and restore hearing for people with severe to profound hearing loss. The primary goals when placing the electrode array are to fully insert the array into the cochlea while minimizing trauma to the cochlea. Studying the relationship between surgical outcome and various surgical techniques has been difficult since trauma and electrode placement are generally unknown without histology. Our group has created a CI placement simulator that combines an interactive 3D visualization environment with a haptic-feedback-enabled controller. Surgical techniques and patient anatomy can be varied between simulations so that outcomes can be studied under varied conditions. With this system, we envision that through numerous trials we will be able to statistically analyze how outcomes relate to surgical techniques. As a first test of this system, in this work, we have designed an experiment in which we compare the spatial distribution of forces imparted to the cochlea in the array insertion procedure when using two different but commonly used surgical techniques for cochlear access, called round window and cochleostomy access. Our results suggest that CIs implanted using round window access may cause less trauma to deeper intracochlear structures than cochleostomy techniques. This result is of interest because it challenges traditional thinking in the otological community but might offer an explanation for recent anecdotal evidence that suggests that round window access techniques lead to better outcomes.

  11. Trends in Intraoperative Testing During Cochlear Implantation.

    Science.gov (United States)

    Page, Joshua Cody; Cox, Matthew D; Hollowoa, Blake; Bonilla-Velez, Juliana; Trinidade, Aaron; Dornhoffer, John L

    2018-03-01

    No consensus guidelines exist regarding intraoperative testing during cochlear implantation and wide variation in practice habits exists. The objective of this observational study was to survey otologists/neurotologists to understand practice habits and overall opinion of usefulness of intraoperative testing. Cross-sectional survey. A web-based survey was sent to 194 practicing Otologists/Neurotologists. Questions included practice setting and experience, habits with respect to electrodes used, intraoperative testing modalities used, overall opinion of intraoperative testing, and practice habits in various scenarios. Thirty-nine of 194 (20%) completed the survey. For routine patients, ECAPs and EIs were most commonly used together (38%) while 33% do not perform testing at all. Eighty-nine percent note that testing "rarely" or "never" changes management. Fifty-one percent marked the most important reason for testing is the reassurance provided to the family and/or the surgeon. Intraoperative testing habits and opinions regarding testing during cochlear implantation vary widely among otologic surgeons. The majority of surgeons use testing but many think there is minimal benefit and that surgical decision-making is rarely impacted. The importance of testing may change as electrodes continue to evolve.

  12. Profile of patients assessed for cochlear implants

    Directory of Open Access Journals (Sweden)

    Maria Helena de Magalhães Barbosa

    2014-07-01

    Full Text Available INTRODUCTION: Knowledge of the characteristics related to profound hearing loss is a matter of great importance, as it allows for the etiological and prognostic identification and strategic planning for public health interventions. OBJECTIVE: To assess the different etiologies of hearing loss, age at diagnosis of the hearing loss, its relation to language acquisition, and the age at the first consultation in this service for cochlear implant assessment. METHODS: This was a historical cohort, cross-sectional study, using retrospective analysis of the records of 115 patients with confirmed sensorineural hearing loss, who were followed in a university hospital, based on gender, age of hearing loss, age at the first consultation, language, and hearing loss etiology. RESULTS AND CONCLUSION: The majority of patients assessed for cochlear implants attend the first consultation when they are older than one year (an alarming mean of 3.8 years in the prelingual group in spite of the early diagnosis of hearing loss. This reflects an already deficient health care system, in terms of referral. The idiopathic cause remains the most frequently identified. Among the known causes, the most prevalent are perinatal causes and meningitis.

  13. LIBRAS AND COCHLEAR IMPLANT: CONTRADICTION OR COMPLEMENTARITY?

    Directory of Open Access Journals (Sweden)

    Lilian Cristine Ribeiro Nascimento

    2015-12-01

    Full Text Available This paper analyses the answers for the interviews carried out with deaf children´s parents about their decision for the rehabilitation and education of their kids, decision which is marked by the simultaneous choice of submitting them to cochlear implant surgery and the exposition to the Brazilian Sign Language. The research’s methodology adopted the historical criticism and the psychoanalysis - hermeneutic analysis for the eight interviews carried out with parents of the children who are regularly enrolled in a bilingual school for deaf children. We tried to analyze the reasons that boosted this specific decision making by parents. The authors that support our research are Freud, and others from psychoanalysis, who helped us understand the subjective motivation boosting parents´ desires and decision making actions; Also, Michel Foucault whose studies helped us comprehend a new human subject appearance and the truth discourse. Our conclusions are that when parents choose this double and simultaneous approach, which families consider as complementary, families are acting their social and cultural roles as parents. The outcomes show us the emergency of a new deaf subject, the bilingual with a Cochlear Implant, that requires some new educational possibilities.

  14. Machinery fault diagnosis using joint global and local/nonlocal discriminant analysis with selective ensemble learning

    Science.gov (United States)

    Yu, Jianbo

    2016-11-01

    The vibration signals of faulty machine are generally non-stationary and nonlinear under those complicated working conditions. Thus, it is a big challenge to extract and select the effective features from vibration signals for machinery fault diagnosis. This paper proposes a new manifold learning algorithm, joint global and local/nonlocal discriminant analysis (GLNDA), which aims to extract effective intrinsic geometrical information from the given vibration data. Comparisons with other regular methods, principal component analysis (PCA), local preserving projection (LPP), linear discriminant analysis (LDA) and local LDA (LLDA), illustrate the superiority of GLNDA in machinery fault diagnosis. Based on the extracted information by GLNDA, a GLNDA-based Fisher discriminant rule (FDR) is put forward and applied to machinery fault diagnosis without additional recognizer construction procedure. By importing Bagging into GLNDA score-based feature selection and FDR, a novel manifold ensemble method (selective GLNDA ensemble, SE-GLNDA) is investigated for machinery fault diagnosis. The motivation for developing ensemble of manifold learning components is that it can achieve higher accuracy and applicability than single component in machinery fault diagnosis. The effectiveness of the SE-GLNDA-based fault diagnosis method has been verified by experimental results from bearing full life testers.

  15. Reduction in spread of excitation from current focusing at multiple cochlear locations in cochlear implant users.

    Science.gov (United States)

    Padilla, Monica; Landsberger, David M

    2016-03-01

    Channel interaction from a broad spread of excitation is likely to be a limiting factor in performance by cochlear implant users. Although partial tripolar stimulation has been shown to reduce spread of excitation, the magnitude of the reduction is highly variable across subjects. Because the reduction in spread of excitation is typically only measured at one electrode for a given subject, the degree of variability across cochlear locations is unknown. The first goal of the present study was to determine if the reduction in spread of excitation observed from partial tripolar current focusing systematically varies across the cochlea. The second goal was to measure the variability in reduction of spread of excitation relative to monopolar stimulation across the cochlea. The third goal was to expand upon previous results that suggest that scaling of verbal descriptors can be used to predict the reduction in spread of excitation, by increasing the limited number of sites previously evaluated and verify the relationships remain with the larger dataset. The spread of excitation for monopolar and partial tripolar stimulation was measured at 5 cochlear locations using a psychophysical forward masking task. Results of the present study suggest that although partial tripolar stimulation typically reduces spread of excitation, the degree of reduction in spread of excitation was found to be highly variable and no effect of cochlear location was found. Additionally, subjective scaling of certain verbal descriptors (Clean/Dirty, Pure/Noisy) correlated with the reduction in spread of excitation suggesting sound quality scaling might be used as a quick clinical estimate of channels providing a reduction in spread of excitation. This quick scaling technique might help clinicians determine which patients would be most likely to benefit from a focused strategy. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Studying the Language Development in Children with Cochlear Implant

    Directory of Open Access Journals (Sweden)

    Marjan Sabri leghaie

    1996-04-01

    Full Text Available Cochlear implant surgery is aimed at making a comprehensive packet of information for the deaf by mixing the data acquired by implanted device and the communicational grammar. Although language production and ability of communication are not main factors in determining the candidacy for cochlear implant surgery, they play crucial role in determining cochlear implant success. we should study the communication skills much deeper than a simple perception and production of speech to have a reasonable evaluation of development of Auditory integration and grammatical language structure. Hence in the current article we will first discuss the grammatical structure in language and then have a look at the pragmatics , semantics and phonological aspects in children with cochlear implant in Virginia college in USA.

  17. Shape Optimization of Cochlear Implant Electrode Array Using Genetic Algorithms

    National Research Council Canada - National Science Library

    Choi, Charles

    2001-01-01

    .... Genetic algorithms are then applied in conjunction with the finite element analysis to optimize the shape of cochlear implant electrode array based on the energy deposited in the spiral ganglion cells region...

  18. Cochlear Implants Keep Twin Sisters Learning, Discovering Together

    Science.gov (United States)

    ... Current Issue Past Issues Special Section: Focus on Communication Cochlear Implants Past Issues / Fall 2008 Table of ... in noisy environments—a critical ability in a classroom. Before the second implant, Mia was pulling back ...

  19. Cochlear implant outcomes in patients with superior canal dehiscence

    NARCIS (Netherlands)

    Puram, Sidharth V.; Roberts, Daniel S.; Niesten, Marlien E F; Dilger, Amanda E.; Lee, Daniel J.

    2015-01-01

    Objective: To determine whether adult cochlear implant (CI) users with superior canal dehiscence syndrome (SCDS) or asymptomatic superior semicircular canal dehiscence (SCD) have different surgical, vestibular, and audiologic outcomes when compared to CI users with normal temporal bone anatomy.

  20. Auditory Mechanics of the Tectorial Membrane and the Cochlear Spiral

    Science.gov (United States)

    Gavara, Núria; Manoussaki, Daphne; Chadwick, Richard S.

    2012-01-01

    Purpose of review This review is timely and relevant since new experimental and theoretical findings suggest that cochlear mechanics from the nanoscale to the macroscale are affected by mechanical properties of the tectorial membrane and the spiral shape. Recent findings Main tectorial membrane themes covered are i) composition and morphology, ii) nanoscale mechanical interactions with the outer hair cell bundle, iii) macroscale longitudinal coupling, iv) fluid interaction with inner hair cell bundles, v) macroscale dynamics and waves. Main cochlear spiral themes are macroscale low-frequency energy focusing and microscale organ of Corti shear gain. Implications Findings from new experimental and theoretical models reveal exquisite sensitivity of cochlear mechanical performance to tectorial membrane structural organization, mechanics, and its positioning with respect to hair bundles. The cochlear spiral geometry is a major determinant of low frequency hearing. Suggestions are made for future research directions. PMID:21785353

  1. Optimizing pneumococcal vaccination for paediatric cochlear implant recipients using the cochlear implant pneumococcal vaccination flowchart.

    Science.gov (United States)

    Moore, Andrew; Harris, Robert; Selvadurai, David

    2012-11-01

    Cochlear implant recipients are known to be at an increased risk of meningitis. It is routine practice to check that pneumococcal vaccinations have been received prior to surgery. Recent changes in United Kingdom national guidelines mean that children who were previously thought to be fully immunized may in fact not be optimally protected. We present a simple, robust audit tool that can be used in both primary care and tertiary centres to identify those children at risk. The pneumococcal immunization status of 63 paediatric cochlear implant recipients was assessed using a unique and comprehensive flowchart-style audit tool. The data collected included age at implantation, details of previous immunizations, and whether or not further vaccinations were required. Fifty-four per cent of children were not optimally immunized prior to implantation. Seventy per cent of children required further vaccinations following surgery. The commonest reason for an incomplete immunization history was failure to administer the 23-valent vaccine after the second birthday. The pneumococcal immunization schedule for high-risk children is complicated and nationally available guidance can be difficult to interpret. There are multiple types of vaccines and their use is not standardized across the UK. Cochlear implant programmes may find that a large proportion of their patients are in fact not optimally vaccinated, particularly in light of recent changes in the national guidelines. Our audit tool allows health professionals, in both primary care and implant centres, to accurately assess the status and immunization requirements for both new and old patients.

  2. A Nonlinear Transmission Line Model of the Cochlea With Temporal Integration Accounts for Duration Effects in Threshold Fine Structure

    DEFF Research Database (Denmark)

    Verhey, Jesko L.; Mauermann, Manfred; Epp, Bastian

    2017-01-01

    than for long signals. The present study demonstrates how this effect can be captured by a nonlinear and active model of the cochlear in combination with a temporal integration stage. Since this cochlear model also accounts for fine structure and connected level dependent effects, it is superior......For normal-hearing listeners, auditory pure-tone thresholds in quiet often show quasi periodic fluctuations when measured with a high frequency resolution, referred to as threshold fine structure. Threshold fine structure is dependent on the stimulus duration, with smaller fluctuations for short...

  3. Language understanding and vocabulary of early cochlear implanted children

    DEFF Research Database (Denmark)

    Percy-Smith, L; Busch, GW; Sandahl, M

    2013-01-01

    The aim of the study was to identify factors associated with the level of language understanding, the level of receptive and active vocabulary, and to estimate effect-related odds ratios for cochlear implanted children's language level.......The aim of the study was to identify factors associated with the level of language understanding, the level of receptive and active vocabulary, and to estimate effect-related odds ratios for cochlear implanted children's language level....

  4. Computational tool for postoperative evaluation of cochlear implant patients

    International Nuclear Information System (INIS)

    Giacomini, Guilherme; Pavan, Ana Luiza M.; Pina, Diana R. de; Altemani, Joao M.C.; Castilho, Arthur M.

    2016-01-01

    The aim of this study was to develop a tool to calculate the insertion depth angle of cochlear implants, from computed tomography exams. The tool uses different image processing techniques, such as thresholding and active contour. Then, we compared the average insertion depth angle of three different implant manufacturers. The developed tool can be used, in the future, to compare the insertion depth angle of the cochlear implant with postoperative response of patient's hearing. (author)

  5. Cochlear implantation in the Mondini inner ear malformation.

    Science.gov (United States)

    Miyamoto, R T; Robbins, A J; Myres, W A; Pope, M L

    1986-07-01

    We report the case of a profoundly deaf 4-year-old boy with congenital deafness as a result of Mondini's dysplasia. The Mondini inner ear malformation is the result of arrested labyrinthine development during embryogenesis and is characterized by both bony and membranous anomalies of the inner ear. The dysplastic cochlear anatomy does not preclude successful cochlear implantation, and electrical threshold measurements are similar to those recorded in pediatric subjects deafened as a result of other causes.

  6. Characterization of Cochlear, Vestibular and Cochlear-Vestibular Electrically Evoked Compound Action Potentials in Patients with a Vestibulo-Cochlear Implant

    Directory of Open Access Journals (Sweden)

    T. A. K. Nguyen

    2017-11-01

    Full Text Available The peripheral vestibular system is critical for the execution of activities of daily life as it provides movement and orientation information to motor and sensory systems. Patients with bilateral vestibular hypofunction experience a significant decrease in quality of life and have currently no viable treatment option. Vestibular implants could eventually restore vestibular function. Most vestibular implant prototypes to date are modified cochlear implants to fast-track development. These use various objective measurements, such as the electrically evoked compound action potential (eCAP, to supplement behavioral information. We investigated whether eCAPs could be recorded in patients with a vestibulo-cochlear implant. Specifically, eCAPs were successfully recorded for cochlear and vestibular setups, as well as for mixed cochlear-vestibular setups. Similarities and slight differences were found for the recordings of the three setups. These findings demonstrated the feasibility of eCAP recording with a vestibulo-cochlear implant. They could be used in the short term to reduce current spread and avoid activation of non-targeted neurons. More research is warranted to better understand the neural origin of vestibular eCAPs and to utilize them for clinical applications.

  7. Hybrid stars within a covariant, nonlocal chiral quark model

    International Nuclear Information System (INIS)

    Blaschke, D. B.; Dumm, D. Gomez; Grunfeld, A. G.; Klaehn, T.; Scoccola, N. N.

    2007-01-01

    We present a hybrid equation of state (EoS) for dense matter in which a nuclear matter phase is described within the Dirac-Brueckner-Hartree-Fock (DBHF) approach and a two-flavor quark matter phase is modelled according to a recently developed covariant, nonlocal chiral quark model. We show that modern observational constraints for compact star masses (M∼2M · ) can be satisfied when a small vector-like four quark interaction is taken into account. The corresponding isospin symmetric EoS is consistent with flow data analyses of heavy ion collisions and points to a deconfinement transition at about 0.55 fm -3

  8. Gas-discharge plasma sources for nonlocal plasma technology

    International Nuclear Information System (INIS)

    Demidov, V. I.; DeJoseph, C. A. Jr.; Simonov, V. Ya.

    2007-01-01

    Nonlocal plasma technology is based on the effect of self-trapping of fast electrons in the plasma volume [V. I. Demidov, C. A. DeJoseph, Jr., and A. A. Kudryavtsev, Phys. Rev. Lett. 95, 215002 (2006)]. This effect can be achieved by changing the ratio of fast electron flux to ion flux incident on the plasma boundaries. This in turn leads to a significant change in plasma properties and therefore can be useful for technological applications. A gas-discharge device which demonstrates control of the plasma properties by this method is described

  9. Detecting nonlocal Cooper pair entanglement by optical Bell inequality violation

    Science.gov (United States)

    Nigg, Simon E.; Tiwari, Rakesh P.; Walter, Stefan; Schmidt, Thomas L.

    2015-03-01

    Based on the Bardeen-Cooper-Schrieffer theory of superconductivity, the coherent splitting of Cooper pairs from a superconductor to two spatially separated quantum dots has been predicted to generate nonlocal pairs of entangled electrons. In order to test this hypothesis, we propose a scheme to transfer the spin state of a split Cooper pair onto the polarization state of a pair of optical photons. We show that the photon pairs produced can be used to violate a Bell inequality, unambiguously demonstrating the entanglement of the split Cooper pairs.

  10. Specific heat of a non-local attractive Hubbard model

    Energy Technology Data Exchange (ETDEWEB)

    Calegari, E.J., E-mail: eleonir@ufsm.br [Laboratório de Teoria da Matéria Condensada, Departamento de Física, UFSM, 97105-900, Santa Maria, RS (Brazil); Lobo, C.O. [Laboratório de Teoria da Matéria Condensada, Departamento de Física, UFSM, 97105-900, Santa Maria, RS (Brazil); Magalhaes, S.G. [Instituto de Física, Universidade Federal Fluminense, Av. Litorânea s/n, 24210, 346, Niterói, Rio de Janeiro (Brazil); Chaves, C.M.; Troper, A. [Centro Brasileiro de Pesquisas Físicas, Rua Xavier Sigaud 150, 22290-180, Rio de Janeiro, RJ (Brazil)

    2013-10-01

    The specific heat C(T) of an attractive (interaction G<0) non-local Hubbard model is investigated within a two-pole approximation that leads to a set of correlation functions, which play an important role as a source of anomalies as the pseudogap. For a giving range of G and n{sub T} (where n{sub T}=n{sub ↑}+n{sub ↓}), the specific heat as a function of the temperature presents a two peak structure. Nevertehelesss, the presence of a pseudogap eliminates the two peak structure. The effects of the second nearest-neighbor hopping on C(T) are also investigated.

  11. Rhetoric, logic, and experiment in the quantum nonlocality debate

    Science.gov (United States)

    Graft, Donald A.

    2017-09-01

    This paper argues that quantum nonlocality (QNL) has not been rigorously proven, despite the existence of recent Einstein-Podolsky-Rosen-Bohm (EPRB) experiments that are claimed to be `loophole-free'. First, readers are alerted to rhetorical arguments, which are unfortunately often appealed to in the QNL debate, to empower readers to identify and reject such arguments. Second, logical problems in QNL proofs are described and exemplified by a discussion of the projection postulate problem. Third, experimental issues are described and exemplified by a discussion of the postselection problem. The paper concludes that QNL has not been proven and that locality cannot be excluded.

  12. Non-local symmetry breaking in Kaluza-Klein theories

    CERN Document Server

    Masiero, A; Serone, M; Silvestrini, L

    2001-01-01

    Scherk-Schwarz gauge symmetry breaking of a D-dimensional field theory model compactified on a circle is analyzed. It is explicitly shown that forbidden couplings in the unbroken theory appear in the one-loop effective action only in a non-local way, implying that they are finite at all orders in perturbation theory. This result can be understood as a consequence of the local gauge symmetry, but holds true also in the global limit. Similar results for Scherk-Schwarz supersymmetry breaking are expected to hold.

  13. Quantization, non-locality and lie-admissible formulations

    International Nuclear Information System (INIS)

    Broadbridge, P.

    1982-01-01

    If higher order wave equations are reduced to first order by supplementary conditions, then quadratic Hamiltonians of the most general type will emerge. Even then, for several reasons elaborated below, canonical quantization can still not be applied consistently. The benefit of clinging to a Lagrangian description of non-localized phenomena is then questionable. Non canonical quantization procedures should be considered. Some initial attempts at Lie-admissible quantization are examined critically here, and it is concluded that further recourse to experiment seems to be necessary

  14. Media psychology: Modern man and nonlocality of psyche.

    Directory of Open Access Journals (Sweden)

    Pronina E.E.

    2014-12-01

    Full Text Available The development of modern information technologies is causing changes in the structure of the human psyche, bringing about a new psychotype. The transition to a new level of evolution is accompanied by the growing manifestation of the psyche’s ontological features — nonlocality and self-determination. From a sample of more than 300 people, it was demonstrated that active Internet users are significantly different in a number of parameters from those who mostly use traditional media. This article examines the resources of media psychology as a new paradigm in the study of mass communication phenomena and the laws of the development of psyche.

  15. Detecting nonlocal Cooper pair entanglement by optical Bell inequality violation

    Energy Technology Data Exchange (ETDEWEB)

    Nigg, Simon E.; Tiwari, Rakesh P.; Walter, Stefan; Schmidt, Thomas L. [Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel (Switzerland)

    2015-07-01

    Based on the Bardeen Cooper Schrieffer (BCS) theory of superconductivity, the coherent splitting of Cooper pairs from a superconductor to two spatially separated quantum dots has been predicted to generate nonlocal pairs of entangled electrons. In order to test this hypothesis, we propose a scheme to transfer the spin state of a split Cooper pair onto the polarization state of a pair of optical photons. We show that the produced photon pairs can be used to violate a Bell inequality, unambiguously demonstrating the entanglement of the split Cooper pairs.

  16. The philosophical implications of quantum non-locality

    Science.gov (United States)

    Jeffries, Paul Christopher

    2000-07-01

    The overarching metaphysics encompassing almost all of science incorporates notions readily recognizable as basic intuitions, such as the separability of nature into parts, and a causal architecture necessitating that influences going from one place to another transit every point in between. Astonishingly, developments in quantum mechanics have all but proven this metaphysics false. An overview of Bell's Theorem sets the stage for a discussion of the philosophical significance of quantum non-locality. An account of the overarching metaphysics of Western science explicates why the violation of the Bell Inequalities is so astonishing, drawing particular attention to the historical and metaphysical issues surrounding action-at-a-distance, and the demands for causal continuity and a finite propagation speed for causal influences. The Chapter Three exegesis of the Einstein-Podolsky-Rosen (EPR) argument contends that a modified version of their ``reality criterion'' side-steps the impression that the argument only goes through under an overly strong realist position, but the truly surprising story underlying the EPR correlations-unforeseen by Einstein and Bohr-comes in the next chapter's examination of Jon P. Jarrett's analysis of non-locality into two composite conditions associated with Einstein's underlying metaphysical principles. This in turn leads to a deeper analysis of the philosophical basis for Einstein's resistance to quantum mechanics. Having seen that a range of ordinary causal and common- cause explanations for the EPR correlations are excluded or burdened with untoward implications, Chapter Seven proposes an information-theoretic analysis of the holistic connection exhibited in quantum phenomena, helping us to better understand in what way constraints on relational holism are responsible for the world appearing to be causally classical. These constraints lead to ``local locality'': the apparent manifestation of a local causal structure when the domain is

  17. Role of nonlocal exchange correlation in activated adsorption

    DEFF Research Database (Denmark)

    Hammer, Bjørk; Jacobsen, Karsten Wedel; Nørskov, Jens Kehlet

    1993-01-01

    The barrier for dissociative adsorption of H-2 on Al(110) has been calculated within the generalized gradient approximation. A pronounced increase of the barrier height is found compared with what is calculated in the local density approximation (LDA). The apparent LDA underestimation...... of the barrier height is shown to be intimately linked with the LDA underbinding of core electrons and we suggest it to be a general phenomenon not limited to the particular nonlocal exchange-correlation approximation used or the particular system studied....

  18. Non-locality versus entanglement in the neutral kaon system

    International Nuclear Information System (INIS)

    Ableitinger, A.; Bertlmann, R.A.; Durstberger, K.; Hiesmayr, B.C.; Krammer, P.

    2006-01-01

    Full text: Particle physics has become an interesting testing ground for fundamental questions of quantum mechanics (QM). The entangled massive meson-antimeson systems are specially suitable as they offer a unique laboratory to test various aspects of particle physics (CP violation, CPT violation, . . . ) as well to test foundations of QM (local realistic theories versus QM, Bell inequalities, decoherence effects, quantum marking and erasure concepts, . . . ). For the neutral kaon system we show that nonlocality detected by the violation of a Bell inequality and entanglement are indeed different concepts. (author)

  19. Non-local quasi-linear parabolic equations

    International Nuclear Information System (INIS)

    Amann, H

    2005-01-01

    This is a survey of the most common approaches to quasi-linear parabolic evolution equations, a discussion of their advantages and drawbacks, and a presentation of an entirely new approach based on maximal L p regularity. The general results here apply, above all, to parabolic initial-boundary value problems that are non-local in time. This is illustrated by indicating their relevance for quasi-linear parabolic equations with memory and, in particular, for time-regularized versions of the Perona-Malik equation of image processing

  20. Temporal nonlinear beam dynamics in infiltrated photonic crystal fibers

    DEFF Research Database (Denmark)

    Bennet, Francis; Rosberg, Christian Romer; Neshev, Dragomir N.

    and technological potential of liquid-infiltrated PCFs it is important to understand the temporal dynamics of nonlinear beam propagation in such structures. In this work we consider thermally induced spatial nonlinear effects in infiltrated photonic crystal fibers. We experimentally study the temporal dynamics......Liquid-infiltrated photonic crystal fibers (PCFs) offer a new way of studying light propagation in periodic and discrete systems. A wide range of available fiber structures combined with the ease of infiltration opens up a range of novel experimental opportunities for optical detection and bio...... the evolution of the fiber output beam in the few micro or milliseconds after the beam is turned on. The characterization of the temporal behavior of the thermal nonlinear response provides important information about the nonlocality associated with heat diffusion inside the fiber, thus enabling studies of long...

  1. Music Perception with Cochlear Implants: A Review

    Science.gov (United States)

    McDermott, Hugh J.

    2004-01-01

    The acceptance of cochlear implantation as an effective and safe treatment for deafness has increased steadily over the past quarter century. The earliest devices were the first implanted prostheses found to be successful in compensating partially for lost sensory function by direct electrical stimulation of nerves. Initially, the main intention was to provide limited auditory sensations to people with profound or total sensorineural hearing impairment in both ears. Although the first cochlear implants aimed to provide patients with little more than awareness of environmental sounds and some cues to assist visual speech-reading, the technology has advanced rapidly. Currently, most people with modern cochlear implant systems can understand speech using the device alone, at least in favorable listening conditions. In recent years, an increasing research effort has been directed towards implant users’ perception of nonspeech sounds, especially music. This paper reviews that research, discusses the published experimental results in terms of both psychophysical observations and device function, and concludes with some practical suggestions about how perception of music might be enhanced for implant recipients in the future. The most significant findings of past research are: (1) On average, implant users perceive rhythm about as well as listeners with normal hearing; (2) Even with technically sophisticated multiple-channel sound processors, recognition of melodies, especially without rhythmic or verbal cues, is poor, with performance at little better than chance levels for many implant users; (3) Perception of timbre, which is usually evaluated by experimental procedures that require subjects to identify musical instrument sounds, is generally unsatisfactory; (4) Implant users tend to rate the quality of musical sounds as less pleasant than listeners with normal hearing; (5) Auditory training programs that have been devised specifically to provide implant users with

  2. Worldwide trends in bilateral cochlear implantation.

    Science.gov (United States)

    Peters, B Robert; Wyss, Josephine; Manrique, Manuel

    2010-05-01

    The goal of this study is to ascertain worldwide experience with bilateral cochlear implantation (BCI) with regard to patient demographics, trends in provision of BCI to adult and child patient populations, differences and similarities in BCI candidacy criteria, diagnostic requirements, and treatment approaches among clinicians in high-volume cochlear implant centers. Retrospective/prospective. : An electronic survey consisting of 59 mainly multiple-choice questions was developed for online completion. It examined the implant experience and clinical opinion of expert cochlear implant (CI) centers worldwide on the indications, motivations, and contraindications for adult and pediatric, simultaneous and sequential BCI candidacy. Centers were chosen to complete the survey based on their known reputation as a center of excellence. Patient demographics were queried for two time periods to elucidate trends: 2006 and prior, and for the year 2007. Seventy-one percent (25/35) of the CI clinics approached completed the survey. Collectively, these 25 clinics represent experience with approximately 23,200 CI users globally, representing 15% of the total estimated CI population worldwide. The total number of BCI surgeries reflected in their experience (2,880) represents 36% of the estimated number worldwide as of December 2007. Cumulatively to the end of 2007, 70% of all BCI surgeries have occurred in children, with the 3- to 10-year-old age group having the highest representation (33% of all BCIs), followed in order by adults (30%), children under 3 years of age (26%), and children between 11 and 18 years of age (11%). Seventy-two percent of all BCI surgeries were performed sequentially (70% of children, 76% of adults). Children adults, 76% sequential). Prior to January 2007, 68% of BCIs were performed in children. This increased to 79% for the year 2007 (P adult BCI patients (59% children, 41% adults) than the non-United States clinics (78% children, 22% adults; P < .001

  3. Bilateral Cochlear Implants: Maximizing Expected Outcomes.

    Science.gov (United States)

    Wallis, Kate E; Blum, Nathan J; Waryasz, Stephanie A; Augustyn, Marilyn

    Sonia is a 4 years 1 month-year-old girl with Waardenburg syndrome and bilateral sensorineural hearing loss who had bilateral cochlear implants at 2 years 7 months years of age. She is referred to Developmental-Behavioral Pediatrics by her speech/language pathologist because of concerns that her language skills are not progressing as expected after the cochlear implant. At the time of the implant, she communicated using approximately 20 signs and 1 spoken word (mama). At the time of the evaluation (18 months after the implant) she had approximately 70 spoken words (English and Spanish) and innumerable signs that she used to communicate. She could follow 1-step directions in English but had more difficulty after 2-step directions.Sonia was born in Puerto Rico at 40 weeks gestation after an uncomplicated pregnancy. She failed her newborn hearing test and was given hearing aids that did not seem to help.At age 2 years, Sonia, her mother, and younger sister moved to the United States where she was diagnosed with bilateral severe-to-profound hearing loss. Genetic testing led to a diagnosis of Waardenburg syndrome (group of genetic conditions that can cause hearing loss and changes in coloring [pigmentation] of the hair, skin, and eyes). She received bilateral cochlear implants 6 months later.Sonia's mother is primarily Spanish-speaking and mostly communicates with her in Spanish or with gestures but has recently begun to learn American Sign Language (ASL). In a preschool program at a specialized school for the deaf, Sonia is learning both English and ASL. Sonia seems to prefer to use ASL to communicate.Sonia receives speech and language therapy (SLT) 3 times per week (90 minutes total) individually in school and once per week within a group. She is also receiving outpatient SLT once per week. Therapy sessions are completed in English, with the aid of an ASL interpreter. Sonia's language scores remain low, with her receptive skills in the first percentile, and her

  4. Establishing the standard method of cochlear implant in Rongchang pig.

    Science.gov (United States)

    Chen, Wei; Yi, Haijin; Zhang, Liang; Ji, Fei; Yuan, Shuolong; Zhang, Yue; Ren, Lili; Li, Jianan; Chen, Lei; Guo, Weiwei; Yang, Shiming

    2017-05-01

    In this investigation, a large mammal, Rongchang pigs were used to successfully establish a research platform for cochlear implant study on the routine use of it in clinic. The aim of this study was to establish a standard method of cochlear implant in a large mammal-pig. Rongchang pigs were selected, then divided into two groups: normal-hearing group (Mitf +/+) and mutation group with hearing loss (Mitf -/-). Cochlear implants were used and ABR and EABR were recorded. The implanted electrodes were observed by X-ray and HE stains. The success with cochlear implant and the best electrode position could be defined in all animals, the coiling of the cochlea reached 1.5-1.75 turns. Immediately after the operation of cochlear implants, the ABR threshold of the operated ear (right) could not be derived for each frequency at 120 dB SPL. Moreover, 7 days after surgery, the low-frequency ABR threshold of the operated ear (right) could be derived partly at 100 dB SPL, but the high-frequency ABR threshold could not be derived at 120 dB SPL. Immediately or 1 week after cochlear implants, the EABR threshold was 90 CL in the Mitf +/+ group. This was obviously lower than the 190 CL in the Mitf -/- group.

  5. Cochlear implantation for single-sided deafness and tinnitus suppression.

    Science.gov (United States)

    Holder, Jourdan T; O'Connell, Brendan; Hedley-Williams, Andrea; Wanna, George

    To quantify the potential effectiveness of cochlear implantation for tinnitus suppression in patients with single-sided deafness using the Tinnitus Handicap Inventory. The study included 12 patients with unilateral tinnitus who were undergoing cochlear implantation for single-sided deafness. The Tinnitus Handicap Inventory was administered at the patient's cochlear implant candidacy evaluation appointment prior to implantation and every cochlear implant follow-up appointment, except activation, following implantation. Patient demographics and speech recognition scores were also retrospectively recorded using the electronic medical record. A significant reduction was found when comparing Tinnitus Handicap Inventory score preoperatively (61.2±27.5) to the Tinnitus Handicap Inventory score after three months of cochlear implant use (24.6±28.2, p=0.004) and the Tinnitus Handicap Inventory score beyond 6months of CI use (13.3±18.9, p=0.008). Further, 45% of patients reported total tinnitus suppression. Mean CNC word recognition score improved from 2.9% (SD 9.4) pre-operatively to 40.8% (SD 31.7) by 6months post-activation, which was significantly improved from pre-operative scores (p=0.008). The present data is in agreement with previously published studies that have shown an improvement in tinnitus following cochlear implantation for the large majority of patients with single-sided deafness. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Production of verb tenses in children with cochlear implants

    Directory of Open Access Journals (Sweden)

    Sokolovac Ivana

    2016-01-01

    Full Text Available The production of verb tenses leads to better language development of children with cochlear implants. The aim of this study was to assess the acquisition of verb tenses in children with cochlear implants. The sample included 60 children, aged from 9 to 15, with average intellectual abilities. The study group consisted of 30 patients with cochlear implants, with no additional disabilities. The control group consisted of 30 subjects with typical speech - language development and preserved hearing. The acquisition of basic tenses was assessed by 'Corpus for the Assessment of the Use of Tenses' (Dimić, 2003. Significant statistical differences were found in the use of the present tense in children with cochlear implants and hearing children (t=-4.385; p<0.001 as well as in the use of the past tense (t=-4.650; p<0.001, and the future tense (t=-4.269; p<0.001. There was also a significant difference in the use of irregular verb 'go' (t=-3.958; p<0.001, as well as in the combination of the present and the past tense (t=-5.806; p<0.001. The present tense was used correctly by most children with cochlear implants (70%, followed by the past tense (53%, and finally the future tense (23%. Children with cochlear implants, even after several years of re/habilitation, do not reach the grammatical development of children with normal hearing.

  7. Quantitative polarized light microscopy of unstained mammalian cochlear sections

    Science.gov (United States)

    Kalwani, Neil M.; Ong, Cheng Ai; Lysaght, Andrew C.; Haward, Simon J.; McKinley, Gareth H.; Stankovic, Konstantina M.

    2013-02-01

    Hearing loss is the most common sensory deficit in the world, and most frequently it originates in the inner ear. Yet, the inner ear has been difficult to access for diagnosis because of its small size, delicate nature, complex three-dimensional anatomy, and encasement in the densest bone in the body. Evolving optical methods are promising to afford cellular diagnosis of pathologic changes in the inner ear. To appropriately interpret results from these emerging technologies, it is important to characterize optical properties of cochlear tissues. Here, we focus on that characterization using quantitative polarized light microscopy (qPLM) applied to unstained cochlear sections of the mouse, a common animal model of human hearing loss. We find that the most birefringent cochlear materials are collagen fibrils and myelin. Retardance of the otic capsule, the spiral ligament, and the basilar membrane are substantially higher than that of other cochlear structures. Retardance of the spiral ligament and the basilar membrane decrease from the cochlear base to the apex, compared with the more uniform retardance of other structures. The intricate structural details revealed by qPLM of unstained cochlear sections ex vivo strongly motivate future application of polarization-sensitive optical coherence tomography to human cochlea in vivo.

  8. [Cochlear implantation in patients with Waardenburg syndrome type II].

    Science.gov (United States)

    Wan, Liangcai; Guo, Menghe; Chen, Shuaijun; Liu, Shuangriu; Chen, Hao; Gong, Jian

    2010-05-01

    To describe the multi-channel cochlear implantation in patients with Waardenburg syndrome including surgeries, pre and postoperative hearing assessments as well as outcomes of speech recognition. Multi-channel cochlear implantation surgeries have been performed in 12 cases with Waardenburg syndrome type II in our department from 2000 to 2008. All the patients received multi-channel cochlear implantation through transmastoid facial recess approach. The postoperative outcomes of 12 cases were compared with 12 cases with no inner ear malformation as a control group. The electrodes were totally inserted into the cochlear successfully, there was no facial paralysis and cerebrospinal fluid leakage occurred after operation. The hearing threshold in this series were similar to that of the normal cochlear implantation. After more than half a year of speech rehabilitation, the abilities of speech discrimination and spoken language of all the patients were improved compared with that of preoperation. Multi-channel cochlear implantation could be performed in the cases with Waardenburg syndrome, preoperative hearing and images assessments should be done.

  9. Canonical approach to constructing constants of motion for nonlocal field theories

    International Nuclear Information System (INIS)

    Garczynski, W.; Stelmach, J.

    1984-01-01

    A general method of derivation of conservation laws for non-local field theories is presented. Differences in comparison with a local case are stressed. Two kinds of Lagrangians appearing in a non-local theory are examined. Canonical choice of constants of motion is made corresponding to the transformations from the conformal and gauge groups. 11 refs. (author)

  10. Nonlocality and optics of inhomogeneous systems : The role of quantum induction

    NARCIS (Netherlands)

    Wijers, C.M.J.; de Boeij, P.L.

    2002-01-01

    Nonlocal interactions play a prominent role in the optics of inhomogeneous systems. Classical discrete dipole descriptions take into account only electro-magnetic nonlocality. This is insufficient to describe correctly the inhomogeneous optical response (e.g., reflectance anisotropy) for covalently

  11. Small scale effect on vibration of embedded multilayered graphene sheets based on nonlocal continuum models

    Energy Technology Data Exchange (ETDEWEB)

    Pradhan, S.C. [Department of Aerospace Engineering Indian Institute of Technology, Kharagpur West Bengal, 721 302 (India)], E-mail: scp@aero.iitkgp.ernet.in; Phadikar, J.K. [Department of Aerospace Engineering Indian Institute of Technology, Kharagpur West Bengal, 721 302 (India)

    2009-03-09

    In the present work, vibration analysis of multilayered graphene sheets embedded in polymer matrix has been carried out employing nonlocal continuum mechanics. Governing equations have been derived using the principle of virtual work. It has been shown that nonlocal effect is quite significant and needs to be included in the continuum model of graphene sheet.

  12. On the origin of nonlocal damping in plasmonic monomers and dimers

    DEFF Research Database (Denmark)

    Tserkezis, Christos; Yan, Wei; Hsieh, Wenting

    2017-01-01

    The origin and importance of nonlocal damping is discussed through simulations with the generalized nonlocal optical response (GNOR) theory, in conjunction with time-dependent density functional theory (TDDFT) calculations and equivalent circuit modeling, for some of the most typical plasmonic...

  13. Local shell-to-shell energy transfer via nonlocal interactions in fluid ...

    Indian Academy of Sciences (India)

    The computation has been done using first-order perturbative field theory. In three dimensions, magnitude of triad interactions is large for nonlocal triads, and small for local triads. However, the shell-to-shell energy transfer rate is found to be local and forward. This result is due to the fact that the nonlocal triads occupy much ...

  14. Are there novel resonances in nanoplasmonic structures due to nonlocal response?

    DEFF Research Database (Denmark)

    Wubs, Martijn; Raza, Søren; Toscano, Giuseppe

    2012-01-01

    In tiny metallic nanostructures, quantum confinement and nonlocal response change the collective plasmonic behaviour with resulting important consequences for e.g. field-enhancement and extinction cross sections. Here we report on nonlocal resonances in the hydrodynamical Drude model for plasmoni...

  15. A simple exposure-time theory for all time-nonlocal transport formulations and beyond.

    Science.gov (United States)

    Ginn, T. R.; Schreyer, L. G.

    2016-12-01

    Anomalous transport or better put, anomalous non-transport, of solutes or flowing water or suspended colloids or bacteria etc. has been the subject of intense analyses with multiple formulations appearing in scientific literature from hydrology to geomorphology to chemical engineering, to environmental microbiology to mathematical physics. Primary focus has recently been on time-nonlocal mass conservation formulations such as multirate mass transfer, fractional-time advection-dispersion, continuous-time random walks, and dual porosity modeling approaches, that employ a convolution with a memory function to reflect respective conceptual models of delays in transport. These approaches are effective or "proxy" ones that do not always distinguish transport from immobilzation delays, are generally without connection to measurable physicochemical properties, and involve variously fractional calculus, inverse Laplace or Fourier transformations, and/or complex stochastic notions including assumptions of stationarity or ergodicity at the observation scale. Here we show a much simpler approach to time-nonlocal (non-)transport that is free of all these things, and is based on expressing the memory function in terms of a rate of mobilization of immobilized mass that is a function of the continguous time immobilized. Our approach treats mass transfer completely independently from the transport process, and it allows specification of actual immobilization mechanisms or delays. To our surprize we found that for all practical purposes any memory function can be expressed this way, including all of those associated with the multi-rate mass transfer approaches, original powerlaw, different truncated powerlaws, fractional-derivative, etc. More intriguing is the fact that the exposure-time approach can be used to construct heretofore unseen memory functions, e.g., forms that generate oscillating tails of breakthrough curves such as may occur in sediment transport, forms for delay

  16. Cochlear vertebral entrapment syndrome: a case report

    Energy Technology Data Exchange (ETDEWEB)

    Liu Chinghsiung; Lin Shinnkuang E-mail: sk1943@adm.cgmh.org.tw; Chang Yeujhy

    2001-11-01

    The authors describe a patient with isolated involvement of vestibulocochlear nerve by a huge vascular loop from vertebral dolichoectasia. No other neurological deficit was found except for unilateral hearing loss. Abnormal brainstem auditory evoked potential study indicated a retrocochlear lesion. The brain computed tomography (CT) and magnetic resonance imaging (MRI) studies demonstrated an abnormally enhanced vascular lesion impinged on the left porus acusticus with a displacement of the brainstem to the right. There was no infarction in the brainstem. A cerebral angiography demonstrated a megadolichoectatic horizontal loop at the intracranial portion of the left vertebral artery. There was no thrombus or atherosclerosis in the vertebrobasilar system. A mechanical compression by a vascular loop is the only possible pathogenesis for hearing loss. The authors diagnose this condition as cochlear vertebral entrapment syndrome.

  17. Ultra-Wideband Transceivers for Cochlear Implants

    Directory of Open Access Journals (Sweden)

    Reisenzahn Alexander

    2005-01-01

    Full Text Available Ultra-wideband (UWB radio offers low power consumption, low power spectral density, high immunity against interference, and other benefits, not only for consumer electronics, but also for medical devices. A cochlear implant (CI is an electronic hearing apparatus, requiring a wireless link through human tissue. In this paper we propose an UWB link for a data rate of Mbps and a propagation distance up to 500 mm. Transmitters with step recovery diode and transistor pulse generators are proposed. Two types of antennas and their filter characteristics in the UWB spectrum will be discussed. An ultra-low-power back tunnel diode receiver prototype is described and compared with conventional detector receivers.

  18. Surface effects on static bending of nanowires based on non-local elasticity theory

    Directory of Open Access Journals (Sweden)

    Quan Wu

    2015-10-01

    Full Text Available The surface elasticity and non-local elasticity effects on the elastic behavior of statically bent nanowires are investigated in the present investigation. Explicit solutions are presented to evaluate the surface stress and non-local elasticity effects with various boundary conditions. Compared with the classical Euler beam, a nanowire with surface stress and/or non-local elasticity can be either stiffer or less stiff, depending on the boundary conditions. The concept of surface non-local elasticity was proposed and its physical interpretation discussed to explain the combined effect of surface elasticity and non-local elasticity. The effect of the nanowire size on its elastic bending behavior was investigated. The results obtained herein are helpful to characterize mechanical properties of nanowires and aid nanowire-based devices design.

  19. Surface effects on the vibration behavior of flexoelectric nanobeams based on nonlocal elasticity theory

    Science.gov (United States)

    Ebrahimi, Farzad; Reza Barati, Mohammad

    2017-01-01

    In this research, vibration characteristics of a flexoelectric nanobeam in contact with Winkler-Pasternak foundation is investigated based on the nonlocal elasticity theory considering surface effects. This nonclassical nanobeam model contains flexoelectric effect to capture coupling of strain gradients and electrical polarizations. Moreover, the nonlocal elasticity theory is employed to study the nonlocal and long-range interactions between the particles. The present model can degenerate into the classical model if the nonlocal parameter, flexoelectric and surface effects are omitted. Hamilton's principle is employed to derive the governing equations and the related boundary conditions which are solved applying a Galerkin-based solution. Natural frequencies are verified with those of previous papers on nanobeams. It is illustrated that flexoelectricity, nonlocality, surface stresses, elastic foundation and boundary conditions affects considerably the vibration frequencies of piezoelectric nanobeams.

  20. A morphing strategy to couple non-local to local continuum mechanics

    KAUST Repository

    Lubineau, Gilles

    2012-06-01

    A method for coupling non-local continuum models with long-range central forces to local continuum models is proposed. First, a single unified model that encompasses both local and non-local continuum representations is introduced. This model can be purely non-local, purely local or a hybrid depending on the constitutive parameters. Then, the coupling between the non-local and local descriptions is performed through a transition (morphing) affecting only the constitutive parameters. An important feature is the definition of the morphing functions, which relies on energy equivalence. This approach is useful in large-scale modeling of materials that exhibit strong non-local effects. The computational cost can be reduced while maintaining a reasonable level of accuracy. Efficiency, robustness and basic properties of the approach are discussed using one- and two-dimensional examples. © 2012 Elsevier Ltd.

  1. The nonlocal Darboux transformation of the 2D stationary Schr\\"odinger equation and its relation to the Moutard transformation

    OpenAIRE

    Kudryavtsev, Andrey

    2013-01-01

    The nonlocal Darboux transformation of the two - dimensional stationary Schr\\"odinger equation is considered and its relation to the Moutard transformation is established. It is shown that a special case of the nonlocal Darboux transformation provides the Moutard transformation. New examples of solvable two - dimensional stationary Schr\\"odinger operators with smooth potentials are obtained as an application of the nonlocal Darboux transformation.

  2. Influence of yttrium iron garnet thickness and heater opacity on the nonlocal transport of electrically and thermally excited magnons

    NARCIS (Netherlands)

    Shan, Juan; Cornelissen, Ludo Johannes; Vlietstra, Nynke; Ben Youssef, J.; Kuschel, Timo; Duine, R A; van Wees, Bart

    2016-01-01

    We studied the nonlocal transport behavior of both electrically and thermally excited magnons in yttrium iron garnet (YIG) as a function of its thickness. For electrically injected magnons, the nonlocal signals decrease monotonically as the YIG thickness increases. For the nonlocal behavior of the

  3. The cochlear nerve canal and internal auditory canal in children with normal cochlea but cochlear nerve deficiency

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Fei; Li, Jianhong; Xian, Junfang; Wang, Zhenchang [Dept. of Radiology, Beijing Tongren Hospital, Capital Medical Univ., Beijing (China)], e-mail: cjr.wzhch@vip.163.com; Mo, Lingyan [Dept. of Otorhinolaryngology, Beijing Tongren Hospital, Capital Medical Univ., Beijing (China)

    2013-04-15

    Background: There is an increasing frequency of requests for cochlear implantation (CI) in deaf children and more detailed image information is necessary for selecting appropriate candidates. Cochlear nerve deficiency (CND) is a contraindication to CI. Magnetic resonance imaging (MRI) has been used to evaluate the integrity of the cochlear nerve. The abnormalities of the cochlear nerve canal (CNC) and internal auditory canal (IAC) have been reported to be associated with CND. Purpose: To correlate CNC manifestation, size, and IAC diameter on high-resolution CT (HRCT) with CND diagnosed by MRI in children. Material and Methods: HRCT images from 35 sensorineurally deaf children who had normal cochlea but bilateral or unilateral CND diagnosed by MRI were studied retrospectively. The CNC and IAC manifestation and size were assessed and correlated with CND. Results: CND was diagnosed by MRI in 54/70 ears (77.1%). Thirty-two ears had an absent cochlear nerve (59.3%), while 22 ears had a small cochlear nerve (40.7%). The CNC diameter was <1.5 mm in 36 ears (66.7%). The CNC diameter ranged between 1.5 and 2.0 mm in seven ears (13.0%) and was >2.0 mm in 11 ears (20.4%). The IAC diameter was <3.0 mm in 25 ears (46.3%) and >3.0 mm in 29 ears (53.7%). Conclusion: The hypoplastic CNC might be more highly indicative of CND than that of a narrow IAC.

  4. A resonance approach to cochlear mechanics.

    Directory of Open Access Journals (Sweden)

    Andrew Bell

    Full Text Available BACKGROUND: How does the cochlea analyse sound into its component frequencies? In the 1850s Helmholtz thought it occurred by resonance, whereas a century later Békésy's work indicated a travelling wave. The latter answer seemed to settle the question, but with the discovery in 1978 that the cochlea emits sound, the mechanics of the cochlea was back on the drawing board. Recent studies have raised questions about whether the travelling wave, as currently understood, is adequate to explain observations. APPROACH: Applying basic resonance principles, this paper revisits the question. A graded bank of harmonic oscillators with cochlear-like frequencies and quality factors is simultaneously excited, and it is found that resonance gives rise to similar frequency responses, group delays, and travelling wave velocities as observed by experiment. The overall effect of the group delay gradient is to produce a decelerating wave of peak displacement moving from base to apex at characteristic travelling wave speeds. The extensive literature on chains of coupled oscillators is considered, and the occurrence of travelling waves, pseudowaves, phase plateaus, and forced resonance in such systems is noted. CONCLUSION AND SIGNIFICANCE: This alternative approach to cochlear mechanics shows that a travelling wave can simply arise as an apparently moving amplitude peak which passes along a bank of resonators without carrying energy. This highlights the possible role of the fast pressure wave and indicates how phase delays and group delays of a set of driven harmonic oscillators can generate an apparent travelling wave. It is possible to view the cochlea as a chain of globally forced coupled oscillators, and this model incorporates fundamental aspects of both the resonance and travelling wave theories.

  5. [Cochlear implants in the social courts].

    Science.gov (United States)

    Lottner, A; Iro, H; Schützenberger, A; Hoppe, U

    2018-02-01

    Since the indication for receiving a cochlear implant (CI) has widened (single-sided deafness [SSD], electric acoustic stimulation [EAS], bilateral CI, CI for long-term deafness), more and more patients come into consideration for such a treatment. Hence, disputes increasingly arise between patients and their insurance companies concerning the question of whether surgery and follow-up treatment have to be paid for by statutory health insurance. This work provides an overview of judgments rendered by the German social courts. We investigated whether and in which cases it is advisable for a patient to go to court, and how long the proceedings may take. We looked for judgments in the two biggest commercial legal databases and in the database of the German social courts, using combinations of the search parameters "Cochlear," "Cochlea," "Implant," and "Implantat." Three verdicts were attained by directly contacting the court; another one was mentioned in an article. The reviewed judgements were issued between 2003 and 2017. A total of 12 judgments were found. The patients won in all but one of the main proceedings. The case that was lost concerned exceptional circumstances. One patient didn't get the desired interim measure, but won in the main proceedings. The proceedings took between 1 year and 8 months, and 9 years and 5 months. Despite the amount of time the patient has to invest, taking legal action is worthwhile. The proceedings at the social courts are generally exempt from charges. In most cases, the statutory health insurance is ordered to pay for a CI.

  6. Cost-Utility of Bilateral Versus Unilateral Cochlear Implantation in Adults: A Randomized Controlled Trial

    NARCIS (Netherlands)

    Smulders, Y.E.; Zon, A. van; Stegeman, I.; Zanten, G.A.; Rinia, A.B.; Stokroos, R.J.; Free, R.H.; Maat, B.; Frijns, J.H.; Mylanus, E.A.M.; Huinck, W.J.; Topsakal, V.; Grolman, W.

    2016-01-01

    OBJECTIVE: To study the cost-utility of simultaneous bilateral cochlear implantation (CI) versus unilateral CI. STUDY DESIGN: Randomized controlled trial (RCT). SETTING: Five tertiary referral centers. PATIENTS: Thirty-eight postlingually deafened adults eligible for cochlear implantation.

  7. Effect of unilateral and simultaneous bilateral cochlear implantation on tinnitus : A Prospective Study

    NARCIS (Netherlands)

    van Zon, Alice; Smulders, Yvette E.; Ramakers, Geerte G. J.; Stegeman, Inge; Smit, Adriana L.; Van Zanten, Gijsbert A.; Stokroos, Robert J.; Hendrice, Nadia; Free, Rolien H.; Maat, Bert; Frijns, Johan H. M.; Mylanus, Emmanuel A. M.; Huinck, Wendy J.; Topsakal, Vedat; Tange, Rinze A.; Grolman, Wilko

    Objectives/HypothesisTo determine the effect of cochlear implantation on tinnitus perception in patients with severe bilateral postlingual sensorineural hearing loss and to demonstrate possible differences between unilateral and bilateral cochlear implantation. Study DesignProspective study.

  8. Nonlinear phonons in high-Tc superconductors mixed crystals

    International Nuclear Information System (INIS)

    Gadzhiev, B.R.; Dzhavadov, N.A.

    1998-01-01

    The integrodifferential kinetic equation which is a generalization of the Landau-Ginzburg formalism is introduced. The peculiarities of nonlinear kinetics are investigated by entering the nonlocal function, which is a quantitative measure of time dispersion. The classification nonlocal function is made by its Hausdorff dimensionality d c . It is shown that in the case d c c =1, the relaxation equation is the equation of damping harmonic oscillator. In the case d c >1, the relaxation equation contains the time derivation arbitrary high order. After linearization of the corresponding dynamic equations near the corresponding nonlinear static equations the dispersion and then after spatial averaging, temperature and frequency dependency of corresponding dynamic susceptibility have been determined. It is shown that in the cases d c c >1 the temperature evolution system alongside with the soft mode is accompanied by the modes which depend nonlinearly on the temperature. The physical nature of quasiscattering in the incommensurate phases of layered crystals is studied. The obtained theoretical results are applied to the layered HTSC crystals. (author)

  9. Outline of a nonlinear, relativistic quantum mechanics of extended particles

    International Nuclear Information System (INIS)

    Mielke, E.W.

    1981-01-01

    A quantum theory of intrinsically extended particles similar to de Broglie's Theory of the Double Solution is proposed. A rational notion of the particle's extension is enthroned by realizing its internal structure via soliton-type solutions of nonlinear, relativistic wave equations. These droplet-type waves have a quasi-objective character except for certain boundary conditions which may be subject to stochastic fluctuations. More precisely, this assumption amounts to a probabilistic description of the center of a soliton such that it would follow the conventional quantum-mechanical formalism in the limit of zero particle radius. At short interaction distances, however, a promising nonlinear and nonlocal theory emerges. This model is not only capable of achieving a conceptually satisfying synthesis of the particle-wave dualism, but may also lead to a rational resolution of epistemological problems in the quantum-theoretical measurement process. Within experimental errors the results for, e.g., the hydrogen atom can be reproduced by appropriately specifying the nature of the nonlinear self-interaction. It is speculated that field theoretical issues raised by such notions as identical particles, field quantization and renormalization are already incorporated or resolved by this nonlocal theory, at least in principle. (author)

  10. Outline of a nonlinear, relativistic quantum mechanics of extended particles

    International Nuclear Information System (INIS)

    Mielke, E.W.

    1981-01-01

    A quantum theory of intrinsically extended particles similar to de Broglie's theory of the Double Solution is proposed. A rational notion of the particle's extension is enthroned by realizing its internal structure via soliton-type solutions of nonlinear, relativistic wave equations. These droplet-type waves have a quasi-objective character except for certain boundary conditions which may be subject to stochastic fluctuations. More precisely, this assumption amounts to a probabilistic description of the center of a soliton such that it would follow the conventional quantum-mechanical formalism in the limit of zero particle radius. At short interaction distances, however, a promising nonlinear and nonlocal theory emerges. This model is not only capable of achieving a conceptually satisfying synthesis of the particle-wave dualism, but may also lead to a rational resolution of epistemological problems in the quantum-theoretical measurement process. Within experimental errors the results for, e.g., the hydrogen atom can be reproduced by appropriately specifying the nature of the nonlinear self-interaction. It is speculated that field theoretical issues raised by such notions as identical particles, field quantization and renormalization are already incorporated or resolved by this nonlocal theory, at least in principle. (author)

  11. Theory of Nonlocal Point Transformations in General Relativity

    Directory of Open Access Journals (Sweden)

    Massimo Tessarotto

    2016-01-01

    Full Text Available A discussion of the functional setting customarily adopted in General Relativity (GR is proposed. This is based on the introduction of the notion of nonlocal point transformations (NLPTs. While allowing the extension of the traditional concept of GR-reference frame, NLPTs are important because they permit the explicit determination of the map between intrinsically different and generally curved space-times expressed in arbitrary coordinate systems. For this purpose in the paper the mathematical foundations of NLPT-theory are laid down and basic physical implications are considered. In particular, explicit applications of the theory are proposed, which concern (1 a solution to the so-called Einstein teleparallel problem in the framework of NLPT-theory; (2 the determination of the tensor transformation laws holding for the acceleration 4-tensor with respect to the group of NLPTs and the identification of NLPT-acceleration effects, namely, the relationship established via general NLPT between particle 4-acceleration tensors existing in different curved space-times; (3 the construction of the nonlocal transformation law connecting different diagonal metric tensors solution to the Einstein field equations; and (4 the diagonalization of nondiagonal metric tensors.

  12. Entanglement, nonlocality and multi-particle quantum correlations

    Science.gov (United States)

    Reid, Margaret D.

    2018-04-01

    This paper contributes to the proceedings of the Latin-American School of Physics (ELAF-2017) on Quantum Correlations, and is a brief review of quantum entanglement and nonlocality. In such a brief review, only some topics can be covered. The emphasis is on those topics relevant that may be relevant to detecting multi-particle quantum correlations arising in atomic and Bose-Einstein condensate (BEC) experiments. The paper is divided into five sections. In the first section, the historical papers of Einstein-Podolsky-Rosen (EPR), Bell, Schrodinger and Greenberger-Zeilinger-Horne (GHZ) are described in a tutorial fashion. This is followed by an introduction to entanglement and density operators. A discussion of the classes of nonlocality is given in the third section, including the modern interpretation of the correlations of the EPR paradox experiments, known as EPR steering correlations. The fourth section covers the detection and generation of so-called continuous variable entanglement and EPR steering. Various known criteria are derived with the details of the proofs given for tutorial purposes. The final section focuses on the criteria and methods that have been useful to detect quantum correlation in BEC or atomic systems. Recent results relating spin squeezing with quantum correlations, including entanglement and EPR steering, are summarised.

  13. Mediation of entanglement and nonlocality of a single fermion

    Science.gov (United States)

    Bernardo, Bertúlio de Lima

    2018-01-01

    Entanglement is one of the most distinctive features of quantum mechanics and is now considered a fundamental resource in quantum information processing, such as in the protocols of quantum teleportation and quantum key distribution. In general, to extract its power in a useful form, it is necessary to generate entanglement between two or more quantum systems separated by long distances, which is not an easy task due to its fragility under environmental disturbance. Here, we propose a method to create entanglement between two distant fermionic particles, which never interact directly by using a third fermion to mediate the correlation. The protocol initiates with three indistinguishable fermions in a separable state, which are allowed to interact in pairs according to the Hong-Ou-Mandel effect. As a result, it is demonstrated that bipartite maximally entangled states can be generated with an efficiency of about 56%, which makes the method a potential candidate for practical quantum information applications. Furthermore, we use the same protocol to show how the mediator fermion exhibits nonlocal properties, giving a new insight on the long-standing discussion about nonlocality of a single particle.

  14. Nonlocal hyperconcentration on entangled photons using photonic module system

    International Nuclear Information System (INIS)

    Cao, Cong; Wang, Tie-Jun; Mi, Si-Chen; Zhang, Ru; Wang, Chuan

    2016-01-01

    Entanglement distribution will inevitably be affected by the channel and environment noise. Thus distillation of maximal entanglement nonlocally becomes a crucial goal in quantum information. Here we illustrate that maximal hyperentanglement on nonlocal photons could be distilled using the photonic module and cavity quantum electrodynamics, where the photons are simultaneously entangled in polarization and spatial-mode degrees of freedom. The construction of the photonic module in a photonic band-gap structure is presented, and the operation of the module is utilized to implement the photonic nondestructive parity checks on the two degrees of freedom. We first propose a hyperconcentration protocol using two identical partially hyperentangled initial states with unknown coefficients to distill a maximally hyperentangled state probabilistically, and further propose a protocol by the assistance of an ancillary single photon prepared according to the known coefficients of the initial state. In the two protocols, the total success probability can be improved greatly by introducing the iteration mechanism, and only one of the remote parties is required to perform the parity checks in each round of iteration. Estimates on the system requirements and recent experimental results indicate that our proposal is realizable with existing or near-further technologies.

  15. Phantom dark energy from nonlocal infrared modifications of general relativity

    Science.gov (United States)

    Maggiore, Michele

    2014-02-01

    We discuss the cosmological consequences of a model based on a nonlocal infrared modification of Einstein equations. We find that the model generates a dynamical dark energy that can account for the presently observed value of ΩDE, without introducing a cosmological constant. Tuning a free mass parameter m to a value m ≃0.67H0, we reproduce the observed value ΩDE≃0.68. This leaves us with no free parameter, and we then get a pure prediction for the equation of state parameter of dark energy. Writing wDE(a)=w0+(1-a)wa, we find w0≃-1.04 and wa≃-0.02, consistent with the Planck data and on the phantom side. We also argue that nonlocal equations of the type that we propose must be understood as purely classical effective equations, such as those derived in semiclassical gravity for the in-in matrix elements of the metric. As such, any apparent ghost instability in such equations only affects the classical dynamics, but there is no propagating degree of freedom associated to the ghost and no issue of ghost-induced quantum vacuum decay.

  16. Cosmological perturbations and observational constraints on nonlocal massive gravity

    Science.gov (United States)

    Nesseris, Savvas; Tsujikawa, Shinji

    2014-07-01

    Nonlocal massive gravity can provide an interesting explanation for the late-time cosmic acceleration, with a dark energy equation of state wDE smaller than -1 in the past. We derive the equations of linear cosmological perturbations to confront such models with the observations of large-scale structures. The effective gravitational coupling to nonrelativistic matter associated with galaxy clusterings is close to Newton's gravitational constant G for a mass scale m slightly smaller than today's Hubble parameter H0. Taking into account the background expansion history as well as the evolution of matter perturbations δm, we test for these models with Type Ia Supernovae (SnIa) from Union 2.1, the cosmic microwave background (CMB) measurements from Planck, a collection of baryon acoustic oscillations (BAO), and the growth rate data of δm. Using a higher value of H0 derived from its direct measurement (H0≳70 km s-1 Mpc-1) the data strongly support the nonlocal massive gravity model (-1.1≲wDE≲-1.04 in the past) over the ΛCDM model (wDE=-1), whereas for a lower prior (67 km s-1 Mpc-1≲H0≲70 km s-1 Mpc-1) the two models are statistically comparable.

  17. Korringa-Kohn-Rostoker nonlocal coherent-potential approximation

    Science.gov (United States)

    Rowlands, D. A.; Staunton, J. B.; Györffy, B. L.

    2003-03-01

    We introduce the Korringa-Kohn-Rostocker nonlocal coherent-potential approximation (KKR-NLCPA) for describing the electronic structure of disordered systems. The KKR-NLCPA systematically provides a hierarchy of improvements upon the widely used KKR-CPA approach and includes nonlocal correlations in the disorder configurations by means of a self-consistently embedded cluster. The KKR-NLCPA method satisfies all of the requirements for a successful cluster generalization of the KKR-CPA; it remains fully causal, becomes exact in the limit of large cluster sizes, reduces to the KKR-CPA for a single-site cluster, is straightforward to implement numerically, and enables the effects of short-range order upon the electronic structure to be investigated. In particular, it is suitable for combination with electronic density-functional theory to give an ab initio description of disordered systems. Future applications to charge correlation and lattice displacement effects in alloys, and spin fluctuations in magnets amongst others, are very promising. We illustrate the method by application to a simple one-dimensional model.

  18. Nonlocal effects in dissociative electron attachment to H2

    International Nuclear Information System (INIS)

    Atems, D.E.; Wadehra, J.M.

    1990-01-01

    Electron scattering by diatomic molecules involving the formation of a single resonance is treated within the configuration-interaction formalism. A technique is presented for solving the resulting nonlocal integro-differential equation for the nuclear motion in the resonant state. This technique is applied to the scattering of electrons by molecular hydrogen (and its isotopes) via the formation of X 2 Σ u + resonance, using a semiempirical model for the resonant state. Numerical cross sections for dissociative attachment, to H 2 , of electrons with energies below 5 eV are presented and compared both with available experimental data and with those obtained using the local approximation for the complete integro-differential equation. In contrast to the local theory, the nonlocal theory predicts cross sections that exhibit discontinuities at energies at which a new vibrational channel opens up. We also give an upper bound for attachment cross sections that holds for all isotopes of molecular hydrogen for all values of the incident electron energies

  19. Aggregation patterns from nonlocal interactions: Discrete stochastic and continuum modeling

    KAUST Repository

    Hackett-Jones, Emily J.

    2012-04-17

    Conservation equations governed by a nonlocal interaction potential generate aggregates from an initial uniform distribution of particles. We address the evolution and formation of these aggregating steady states when the interaction potential has both attractive and repulsive singularities. Currently, no existence theory for such potentials is available. We develop and compare two complementary solution methods, a continuous pseudoinverse method and a discrete stochastic lattice approach, and formally show a connection between the two. Interesting aggregation patterns involving multiple peaks for a simple doubly singular attractive-repulsive potential are determined. For a swarming Morse potential, characteristic slow-fast dynamics in the scaled inverse energy is observed in the evolution to steady state in both the continuous and discrete approaches. The discrete approach is found to be remarkably robust to modifications in movement rules, related to the potential function. The comparable evolution dynamics and steady states of the discrete model with the continuum model suggest that the discrete stochastic approach is a promising way of probing aggregation patterns arising from two- and three-dimensional nonlocal interaction conservation equations. © 2012 American Physical Society.

  20. CT and MR imaging for pediatric cochlear implantation: emphasis on the relationship between the cochlear nerve canal and the cochlear nerve

    Energy Technology Data Exchange (ETDEWEB)

    Miyasaka, Mikiko; Nosaka, Shunsuke; Masaki, Hidekazu [National Center for Child Health and Development, Department of Radiology, Tokyo (Japan); Morimoto, Noriko; Taiji, Hidenobu [National Center for Child Health and Development, Department of Otolaryngology, Tokyo (Japan)

    2010-09-15

    Cochlear implantation has become an accepted treatment for deafness. As the frequency of cochlear implantation has increased, requests for images have also increased in the work-up for candidates. An absent cochlear nerve (CN) is a contraindication to cochlear implantation. Therefore, MRI is performed to evaluate the CN in patients with sensorineural hearing loss. Recently, some authors have reported the relationship between cochlear nerve canal (CNC) stenosis and CN hypoplasia. To review the relationship between CNC and CN. During a period of 78 months, 21 children (42 ears) with unilateral or bilateral sensorineural hearing loss underwent both HRCT and MRI of the cochlear nerve. We retrospectively reviewed two factors: the evaluation of inner ear malformations and the relationship between CNC stenosis and CN hypoplasia. Inner ear malformations were recognized in ten ears. The mean CNC diameter was approximately 2 mm (ranging from 0.6 to 2.7 mm). CN hypoplasia was seen in eight of the 42 ears; all eight were associated with CNC stenosis ({<=}1.5 mm). Of the 34 ears with normal CN, 32 had CNC >1.5 mm in diameter and the remaining two ears, with incomplete partition type I, had CNC stenosis. Children with CNC stenosis had a high incidence of CN hypoplasia. CNC stenosis ({<=}1.5 mm) suggests CN hypoplasia. On the other hand, CN hypoplasia was not seen in children with CNC diameter >1.5 mm. Therefore, we conclude that children with CNC stenosis or malformations on HRCT should receive MR imaging of the CN. (orig.)