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1

Photon wave function  

E-print Network

Photon wave function is a controversial concept. Controversies stem from the fact that photon wave functions can not have all the properties of the Schroedinger wave functions of nonrelativistic wave mechanics. Insistence on those properties that, owing to peculiarities of photon dynamics, cannot be rendered, led some physicists to the extreme opinion that the photon wave function does not exist. I reject such a fundamentalist point of view in favor of a more pragmatic approach. In my view, the photon wave function exists as long as it can be precisely defined and made useful.

Iwo Bialynicki-Birula

2005-08-26

2

The impact of the ocean wave-radar modulation transfer function on the inversion of ERS-1 SAR image spectra into ocean wave spectra  

Microsoft Academic Search

Hasselmann's closed forward integral transform and its inversion includes, in addition to motion induced effects, the modulation of the normalized radar cross section (NRCS) due to long ocean waves. This modulation is described by a linear ocean wave-radar modulation transfer function (MTF). The authors compute the forward mapping integral by using a `theoretical' and a parameterized form of the MTF

Claus Bruning

1994-01-01

3

Wave Function Ontology  

Microsoft Academic Search

I argue that the wave function ontology for quantum mechanics is an undesirable ontology. This ontology holds that the fundamental space in which entities evolve is not three-dimensional, but instead 3N-dimensional, where N is the number of particles standardly thought to exist in three-dimensional space. I show that the state of three-dimensional objects does not supervene on the state of

Bradley Monton

2002-01-01

4

Wave function of the Universe  

Microsoft Academic Search

The quantum state of a spatially closed universe can be described by a wave function which is a functional on the geometries of compact three-manifolds and on the values of the matter fields on these manifolds. The wave function obeys the Wheeler-DeWitt second-order functional differential equation. We put forward a proposal for the wave function of the ''ground state'' or

J. B. Hartle; S. W. Hawking

1983-01-01

5

Uncollapsing the wave function  

E-print Network

The space quantization induced by a Stern-Gerlach experiment is normally explained by invoking the ``collapse of the wave function.'' This is a rather mysterious idea; it would be better to explain the Stern-Gerlach results without using it. We re-analyze the Stern-Gerlach experiment using path integrals. We find if we model explicitly the finite width of the beam, coherent interference within the beam itself provides the space quantization -- without need to invoke the collapse. If we insist on employing only wave functions with the space and spin parts kept forcibly disentangled, we recreate the need to invoke the collapse. The collapse-free approach makes more specific predictions about the shape and position of the scattered beams; if the interaction region has finite length, these may be testable. Pending experimental disambiguation, the chief arguments in favor of the collapse-free approach are that it is simpler and less mysterious, has no adjustable parameters, and requires the invocation of no new forces.

John Ashmead

2003-01-07

6

Random wave functions and percolation  

E-print Network

Recently it was conjectured that nodal domains of random wave functions are adequately described by critical percolation theory. In this paper we strengthen this conjecture in two respects. First, we show that, though wave function correlations decay slowly, a careful use of Harris' criterion confirms that these correlations are unessential and nodal domains of random wave functions belong to the same universality class as non critical percolation. Second, we argue that level domains of random wave functions are described by the non-critical percolation model.

E. Bogomolny; C. Schmit

2007-08-31

7

Wave function as geometric entity  

E-print Network

A new approach to the geometrization of the electron theory is proposed. The particle wave function is represented by a geometric entity, i.e., Clifford number, with the translation rules possessing the structure of Dirac equation for any manifold. A solution of this equation is obtained in terms of geometric treatment. Interference of electrons whose wave functions are represented by geometric entities is considered. New experiments concerning the geometric nature of electrons are proposed.

B. I. Lev

2011-02-10

8

Wave-function functionals for the density  

SciTech Connect

We extend the idea of the constrained-search variational method for the construction of wave-function functionals {psi}[{chi}] of functions {chi}. The search is constrained to those functions {chi} such that {psi}[{chi}] reproduces the density {rho}(r) while simultaneously leading to an upper bound to the energy. The functionals are thereby normalized and automatically satisfy the electron-nucleus coalescence condition. The functionals {psi}[{chi}] are also constructed to satisfy the electron-electron coalescence condition. The method is applied to the ground state of the helium atom to construct functionals {psi}[{chi}] that reproduce the density as given by the Kinoshita correlated wave function. The expectation of single-particle operators W={Sigma}{sub i}r{sub i}{sup n}, n=-2,-1,1,2, W={Sigma}{sub i}{delta}(r{sub i}) are exact, as must be the case. The expectations of the kinetic energy operator W=-(1/2){Sigma}{sub i}{nabla}{sub i}{sup 2}, the two-particle operators W={Sigma}{sub n}u{sup n}, n=-2,-1,1,2, where u=|r{sub i}-r{sub j}|, and the energy are accurate. We note that the construction of such functionals {psi}[{chi}] is an application of the Levy-Lieb constrained-search definition of density functional theory. It is thereby possible to rigorously determine which functional {psi}[{chi}] is closer to the true wave function.

Slamet, Marlina; Pan Xiaoyin; Sahni, Viraht [Sacred Heart University, Fairfield, Connecticut 06825 (United States); Faculty of Science, Ningbo University, 315211 Ningbo (China); Brooklyn College and The Graduate School of the City University of New York, New York, New York 10016 (United States)

2011-11-15

9

Dirac wave functions in nuclear distorted-wave calculations  

SciTech Connect

A distorted-wave formulation of simple direct nuclear reactions, using Dirac wave functions, is presented. The resulting amplitude contains interior damping due to relativistic Darwin terms. The calculations are compared with standard Schroedinger results and significant differences are found.

Rost, E.; Shepard, J.R.; Murdock, D.

1982-08-16

10

Meson wave function from holographic approaches  

SciTech Connect

We discuss the light-front wave function for the valence quark state of mesons using the AdS/CFT correspondence. We consider two kinds of wave functions obtained in different holographic Soft-Wall approaches.

Vega, Alfredo; Schmidt, Ivan [Departamento de Fisica y Centro de Estudios Subatomicos, Universidad Tecnica Federico Santa Maria, Casilla 110-V, Valparaiso (Chile); Branz, Tanja; Gutsche, Thomas; Lyubovitskij, Valery E. [Institut fuer Theoretische Physik, Universitaet Tuebingen, Kepler Center for Astro and Particle Physics, Auf der Morgenstelle 14, D-72076 Tuebingen (Germany)

2010-08-04

11

The destructive impact of the rogue waves  

NASA Astrophysics Data System (ADS)

In our talk rogue waves at the ocean will be considered. By means of numerical modeling dangerous impact of rogue waves on the ships and oil rigs is calculated. Cases when these waves can bring in accident are considered. Using statistics of emergence of waves (see [1]-[2]), it is possible to estimate risks in each case. These results can be used for safety of the ships and oil rigs from rogue waves. References [1] V.E. Zakharov, A.I. Dyachenko, R.V. Shamin. How probability for freak wave formation can be found // THE EUROPEAN PHYSICAL JOURNAL - SPECIAL TOPICS Volume 185, Number 1, 113-124, DOI: 10.1140/epjst/e2010-01242-y [2] V.E. Zakharov, R.V. Shamin. Statistics of rogue waves in computer experiments // JETP Letters, 2012, V. 96, Issue 1, pp 66-69.

Shamin, Roman

2013-04-01

12

Does the Schrödinger wave function describe a real physical wave?  

NASA Astrophysics Data System (ADS)

In 1924 Louis de Broglie presented the phase wave model [1]. He postulated that particle and wave coexist. Both objects are coupled to each other by the phase harmony principle, which always tends to synchronize the oscillations of wave and particle. The escort wave model [2] replenishes the phase wave model by attributing a stochastic velocity component and a potential dependent rest mass to the particle. Moreover it introduces a novel method to deal with standing waves. In this new model a particle's trajectory is continuous but not deterministic because the particle is not only subjected to regular forces derived from external potentials but also to fluctuating forces. On this condition the space dependence of the wave escorting a particle agrees with the Schrödinger wave function. By a measurement process the phase harmony coupling is broken off. Contrary to the standard interpretation of quantum mechanics the escort wave does not collapse but disappears in the ocean of fluctuating waves, because it is no longer stabilized by the particle. The particle immediately starts to build up a new escort wave by adjusting its phase to the phases of fluctuating waves, whose frequencies and rest systems nearly agree with the corresponding magnitudes of the particle.

Jung, Kurt

2011-07-01

13

Meson wave function from holographic models  

E-print Network

We consider the light-front wave function for the valence quark state of mesons using the AdS/CFT correspondence, as has been suggested by Brodsky and Teramond. Two kinds of wave functions, obtained in different holographic Soft-Wall models, are discussed.

Alfredo Vega; Ivan Schmidt; Tanja Branz; Thomas Gutsche; Valery Lyubovitskij

2009-06-05

14

Wave function derivation of the JIMWLK equation  

E-print Network

Using the stationary lightcone perturbation theory, we propose the complete and careful derivation the JIMWLK equation. We show that the rigorous treatment requires the knowledge of a boosted wave function with second order accuracy. Previous wave function approaches are incomplete and implicitly used the time ordered perturbation theory, which requires a usage of an external target field.

Alexey V. Popov

2008-06-19

15

Variational wave functions for homogenous Bose systems  

Microsoft Academic Search

We study variational wave functions of the product form, factorizing according to the wave vectors k, for the ground state of a system of bosons interacting via positive pair interactions with a positive Fourier transform. Our trial functions are members of different orthonormal bases in Fock space. Each basis contains a quasiparticle vacuum state and states with an arbitrary finite

Andras Sueto; Peter Szepfalusy

2008-01-01

16

Variational wave functions for homogenous Bose systems  

Microsoft Academic Search

We study variational wave functions of the product form, factorizing according to the wave vectors k , for the ground state of a system of bosons interacting via positive pair interactions with a positive Fourier transform. Our trial functions are members of different orthonormal bases in Fock space. Each basis contains a quasiparticle vacuum state and states with an arbitrary

András Süto; Péter Szépfalusy

2008-01-01

17

A Wave-function for Stringy Universes  

E-print Network

We define a wave-function for string theory cosmological backgrounds. We give a prescription for computing its norm following an earlier analysis within general relativity. Under Euclidean continuation, the cosmologies we discuss in this paper are described in terms of compact parafermionic worldsheet systems. To define the wave-function we provide a T-fold description of the parafermionic conformal field theory, and of the corresponding string cosmology. In specific examples, we compute the norm of the wave-function and comment on its behavior as a function of moduli.

Costas Kounnas; Nicolaos Toumbas; Jan Troost

2007-04-16

18

The Wave Function and Quantum Reality  

E-print Network

We investigate the meaning of the wave function by analyzing the mass and charge density distribution of a quantum system. According to protective measurement, a charged quantum system has mass and charge density proportional to the modulus square of its wave function. It is shown that the mass and charge density is not real but effective, and it is formed by the ergodic motion of a localized particle with the total mass and charge of the system. Moreover, it is argued that the ergodic motion is not continuous but discontinuous and random. This result suggests a new interpretation of the wave function, according to which the wave function is a description of random discontinuous motion of particles, and the modulus square of the wave function gives the probability density of the particles being in certain locations. It is shown that the suggested interpretation of the wave function disfavors the de Broglie-Bohm theory and the many-worlds interpretation but favors the dynamical collapse theories, and the random discontinuous motion of particles may provide an appropriate random source to collapse the wave function.

Shan Gao

2011-08-04

19

Sculpturing the Electron Wave Function  

E-print Network

Coherent electrons such as those in electron microscopes, exhibit wave phenomena and may be described by the paraxial wave equation. In analogy to light-waves, governed by the same equation, these electrons share many of the fundamental traits and dynamics of photons. Today, spatial manipulation of electron beams is achieved mainly using electrostatic and magnetic fields. Other demonstrations include simple phase-plates and holographic masks based on binary diffraction gratings. Altering the spatial profile of the beam may be proven useful in many fields incorporating phase microscopy, electron holography, and electron-matter interactions. These methods, however, are fundamentally limited due to energy distribution to undesired diffraction orders as well as by their binary construction. Here we present a new method in electron-optics for arbitrarily shaping of electron beams, by precisely controlling an engineered pattern of thicknesses on a thin-membrane, thereby molding the spatial phase of the electron wav...

Shiloh, Roy; Lilach, Yigal; Arie, Ady

2014-01-01

20

Stress Wave Source Characterization: Impact, Fracture, and Sliding Friction  

NASA Astrophysics Data System (ADS)

Rapidly varying forces, such as those associated with impact, rapid crack propagation, and fault rupture, are sources of stress waves which propagate through a solid body. This dissertation investigates how properties of a stress wave source can be identified or constrained using measurements recorded at an array of sensor sites located far from the source. This methodology is often called the method of acoustic emission and is useful for structural health monitoring and the noninvasive study of material behavior such as friction and fracture. In this dissertation, laboratory measurements of 1--300 mm wavelength stress waves are obtained by means of piezoelectric sensors which detect high frequency (10 kHz--3MHz) motions of a specimen's surface, picometers to nanometers in amplitude. Then, stress wave source characterization techniques are used to study ball impact, drying shrinkage cracking in concrete, and the micromechanics of stick-slip friction of Poly(methyl methacrylate) (PMMA) and rock/rock interfaces. In order to quantitatively relate recorded signals obtained with an array of sensors to a particular stress wave source, wave propagation effects and sensor distortions must be accounted for. This is achieved by modeling the physics of wave propagation and transduction as linear transfer functions. Wave propagation effects are precisely modeled by an elastodynamic Green's function, sensor distortion is characterized by an instrument response function, and the stress wave source is represented with a force moment tensor. These transfer function models are verified though calibration experiments which employ two different mechanical calibration sources: ball impact and glass capillary fracture. The suitability of the ball impact source model, based on Hertzian contact theory, is experimentally validated for small (˜1 mm) balls impacting massive plates composed of four different materials: aluminum, steel, glass, and PMMA. Using this transfer function approach and the two mechanical calibration sources, four types of piezoelectric sensors were calibrated: three commercially available sensors and the Glaser-type conical piezoelectric sensor, which was developed in the Glaser laboratory. The distorting effects of each sensor are modeled using autoregressive-moving average (ARMA) models, and because vital phase information is robustly incorporated into these models, they are useful for simulating or removing sensor-induced distortions, so that a displacement time history can be retrieved from recorded signals. The Glaser-type sensor was found to be very well modeled as a unidirectional displacement sensor which detects stress wave disturbances down to about 1 picometer in amplitude. Finally, the merits of a fully calibrated experimental system are demonstrated in a study of stress wave sources arising from sliding friction, and the relationship between those sources and earthquakes. A laboratory friction apparatus was built for this work which allows the micro-mechanisms of friction to be studied with stress wave analysis. Using an array of 14 Glaser-type sensors, and precise models of wave propagation effects and the sensor distortions, the physical origins of the stress wave sources are explored. Force-time functions and focal mechanisms are determined for discrete events found amid the "noise" of friction. These localized events are interpreted to be the rupture of micrometer-sized contacts, known as asperities. By comparing stress wave sources from stick-slip experiments on plastic/plastic and rock/rock interfaces, systematic differences were found. The rock interface produces very rapid (<1 microsecond) implosive forces indicative of brittle asperity failure and fault gouge formation, while rupture on the plastic interface releases only shear force and produces a source more similar to earthquakes commonly recorded in the field. The difference between the mechanisms is attributed to the vast differences in the hardness and melting temperatures of the two materials, which affect the distribution of asp

McLaskey, Gregory Christofer

21

FQH Droplets Wave Function on Spheres  

Microsoft Academic Search

Using matrix model formulation of Laughlin fluid as well as su(2) representation theory, we consider fractional Quantum Hall system on 3d and 2d spheres and derive explicitly the ground state wave function of the corresponding fluid droplets.

R. Ahl Laamara; L. B Drissi; E. H Saidi

2007-01-01

22

The Maxwell wave function of the photon  

E-print Network

James Clerk Maxwell unknowingly discovered a correct relativistic, quantum theory for the light quantum, forty-three years before Einstein postulated the photon's existence. In this theory, the usual Maxwell field is the quantum wave function for a single photon. When the non-operator Maxwell field of a single photon is second quantized, the standard Dirac theory of quantum optics is obtained. Recently, quantum-state tomography has been applied to experimentally determine photon wave functions.

M. G. Raymer; Brian J. Smith

2006-04-24

23

Interferometric Measurement of the Biphoton Wave Function  

NASA Astrophysics Data System (ADS)

Interference between an unknown two-photon state (a "biphoton") and the two-photon component of a reference state gives a phase-sensitive arrival-time distribution containing full information about the biphoton temporal wave function. Using a coherent state as a reference, we observe this interference and reconstruct the wave function of single-mode biphotons from a low-intensity narrow band squeezed vacuum state.

Beduini, Federica A.; Zieli?ska, Joanna A.; Lucivero, Vito G.; de Icaza Astiz, Yannick A.; Mitchell, Morgan W.

2014-10-01

24

Neutrino wave function and oscillation suppression  

E-print Network

We consider a thought experiment, in which a neutrino is produced by an electron on a nucleus in a crystal. The wave function of the oscillating neutrino is calculated assuming that the electron is described by a wave packet. If the electron is relativistic and the spatial size of its wave packet is much larger than the size of the crystal cell, then the wave packet of the produced neutrino has essentially the same size as the wave packet of the electron. We investigate the suppression of neutrino oscillations at large distances caused by two mechanisms: 1) spatial separation of wave packets corresponding to different neutrino masses; 2) neutrino energy dispersion for given neutrino mass eigenstates. We resolve contributions of these two mechanisms.

A. D. Dolgov; O. V. Lychkovskiy; A. A. Mamonov; L. B. Okun; M. G. Schepkin

2005-06-21

25

Modeling of Wave Impact Using a Pendulum System  

E-print Network

For high speed vessels and offshore structures, wave impact, a main source of environmental loads, causes high local stresses and structural failure. However, the prediction of wave impact loads presents numerous challenges due to the complex nature...

Nie, Chunyong

2011-08-08

26

Weak measurement and Bohmian conditional wave functions  

NASA Astrophysics Data System (ADS)

It was recently pointed out and demonstrated experimentally by Lundeen et al. that the wave function of a particle (more precisely, the wave function possessed by each member of an ensemble of identically-prepared particles) can be “directly measured” using weak measurement. Here it is shown that if this same technique is applied, with appropriate post-selection, to one particle from a perhaps entangled multi-particle system, the result is precisely the so-called “conditional wave function” of Bohmian mechanics. Thus, a plausibly operationalist method for defining the wave function of a quantum mechanical sub-system corresponds to the natural definition of a sub-system wave function which Bohmian mechanics uniquely makes possible. Similarly, a weak-measurement-based procedure for directly measuring a sub-system's density matrix should yield, under appropriate circumstances, the Bohmian “conditional density matrix” as opposed to the standard reduced density matrix. Experimental arrangements to demonstrate this behavior-and also thereby reveal the non-local dependence of sub-system state functions on distant interventions-are suggested and discussed.

Norsen, Travis; Struyve, Ward

2014-11-01

27

Weak Measurement and (Bohmian) Conditional Wave Functions  

E-print Network

It was recently pointed out (and demonstrated experimentally) by Lundeen et al. that the wave function of a particle (more precisely, the wave function possessed by each member of an ensemble of identically-prepared particles) can be "directly measured" using weak measurement. Here it is shown that if this same technique is applied, with appropriate post-selection, to one particle from a (perhaps entangled) multi-particle system, the result is precisely the so-called "conditional wave function" of Bohmian mechanics. Thus, a plausibly operationalist method for defining the wave function of a quantum mechanical sub-system corresponds to the natural definition of a sub-system wave function which Bohmian mechanics (uniquely) makes possible. Similarly, a weak-measurement-based procedure for directly measuring a sub-system's density matrix should yield, under appropriate circumstances, the Bohmian "conditional density matrix" as opposed to the standard reduced density matrix. Experimental arrangements to demonstrate this behavior -- and also thereby reveal the non-local dependence of sub-system state functions on distant interventions -- are suggested and discussed.

Travis Norsen; Ward Struyve

2013-05-10

28

(e,2e) simple ionization of CO2 by fast electron impact: use of three-center parameterized continuum wave function and Dyson orbitals  

NASA Astrophysics Data System (ADS)

The variation of the triple differential cross section of the (e,2e) simple ionization of CO2 with the direction of the ejected electron is studied. The calculations are performed in the frame of a perturbative first Born procedure, using a three-center Dyson type description for the 1?g bound electron and an approximate three-center continuum solution of the corresponding Schrödinger equation for a specific wave vector {{{k}}e} for the free ejected electron, which satisfies the correct asymptotic boundary condition up to the order O({{(kr)}-2}). Empirical values for the screening of the three nuclei of the target and for the Sommerfeld parameters of the three-center Coulomb continuum function are introduced. The results are compared to existing experimental results and a theoretical result obtained by the same approach, using a Hartree–Fock Slater type orbital.

Alwan, O.; Chuluunbaatar, O.; Assfeld, X.; Naja, A.; Joulakian, B. B.

2014-11-01

29

Spectroscopic measurement of an atomic wave function  

SciTech Connect

We present a simple spectroscopic method based on Autler-Townes spectroscopy to determine the center-of-mass atomic wave function. The detection of spontaneously emitted photons from a three-level atom, in which two upper levels are driven by a classical standing light, yields information about the position and momentum distribution of the atom [A. M. Herkommer, W. P. Schleich, and M. S. Zubairy, J. Mod. Opt. 44, 2507 (1997)]. In this paper, we show that both the amplitude and phase information of the center-of-mass atomic wave function can be obtained from these distributions after a series of conditional measurements on the atom and the emitted photon.

Kapale, Kishore T. [Institute for Quantum Studies, and Department of Physics, Texas A and M University, College Station, Texas 77843-4242 (United States); Qamar, Shahid [Institute for Quantum Studies, and Department of Physics, Texas A and M University, College Station, Texas 77843-4242 (United States); Department of Physics and Applied Mathematics, Pakistan Institute of Engineering and Applied Science, Nilore, Islamabad (Pakistan); Zubairy, M. Suhail [Institute for Quantum Studies, and Department of Physics, Texas A and M University, College Station, Texas 77843-4242 (United States); Department of Electronics, Quaid-i-Azam University, Islamabad (Pakistan)

2003-02-01

30

Instantaneous frequency and wave shape functions (I)  

E-print Network

Although one can formulate an intuitive notion of instantaneous frequency, generalizing "frequency" as we understand it in e.g. the Fourier transform, a rigorous mathematical definition is lacking. In this paper, we consider a class of functions composed of waveforms that repeat nearly periodically, and for which the instantaneous frequency can be given a rigorous meaning. We shown that Synchrosqueezing can be used to determine the instantaneous frequency of functions in this class, even if the waveform is not harmonic, thus generalizing earlier results for cosine wave functions. We also provide real-life examples and discuss the advantages, for these examples, of considering such non-harmonic waveforms.

Wu, Hau-tieng

2011-01-01

31

Universal wave functions structure in mixed systems  

E-print Network

When a regular classical system is perturbed, non-linear resonances appear as prescribed by the KAM and Poincar\\`{e}-Birkhoff theorems. Manifestations of this classical phenomena to the morphologies of quantum wave functions are studied in this letter. We reveal a systematic formation of an universal structure of localized wave functions in systems with mixed classical dynamics. Unperturbed states that live around invariant tori are mixed when they collide in an avoided crossing if their quantum numbers differ in a multiple to the order of the classical resonance. At the avoided crossing eigenstates are localized in the island chain or in the vicinity of the unstable periodic orbit corresponding to the resonance. The difference of the quantum numbers determines the excitation of the localized states which is reveled using the zeros of the Husimi distribution.

Diego A. Wisniacki

2014-03-02

32

Photon wave functions and quantum interference experiments  

Microsoft Academic Search

We present a general theory to describe two-photon interference, including a formal description of few photon intereference in terms of single-photon amplitudes. With this formalism, it is possible to describe both frequency entangled and separable two-photon interference in terms of single-photon wave functions. Using this description, we address issues related to the physical interpretation of two-photon interference experiments. We include

G. G. Lapaire; J. E. Sipe

2006-01-01

33

Parametric Dependence of Ocean Wave-Radar Modulation Transfer Functions  

Microsoft Academic Search

much smaller when the antennas are pointed perpendicular to long waves, however. X band transfer functions measured with horizontally polarized microwave radiation are found to have larger magnitudes than those obtained by using vertical polarization. Under conditions encountered in this experiment, transfer functions are independent of long-wave amplitude when waves and antennas are aligned. Coherence functions, however, depend strongly on

W. J. Plant; W. C. Keller; A. Cross

1983-01-01

34

On Dissipation Function of Ocean Waves due to Whitecapping.  

E-print Network

On Dissipation Function of Ocean Waves due to Whitecapping. V.E. Zakharov, A.O. Korotkevich, and A Dissipation Function of Ocean Waves due to White Capping. Scheme of scales kp1 k=2/ pumping inverse cascade Function of Ocean Waves due to White Capping. Why it is important? ­ L.D. Landau ITP RAS ­ Zakharov-70, SCT

Fominov, Yakov

35

Improved wave function for strongly correlated electronic systems  

Microsoft Academic Search

A scheme of optimization of a trial wave function in the variational Monte Carlo calculation is developed. It provides a more precise description of the ground state for strongly correlated electronic systems with highly improved trial wave function. A general type of variational wave function constructed from a linear combination of Slater determinants multiplied by Jastrow correlation factors is proposed.

Kenji Kobayashi; Kaoru Iguchi

1993-01-01

36

Lee-Yang measures and wave functions  

E-print Network

We establish necessary and sufficient conditions for a Borel measure to be a Lee-Yang one which means that its Fourier transform possesses only real zeros. Equivalently, we answer a question of P\\'olya who asked for a characterisation of those positive positive, even and sufficiently fast decaying kernels whose Fourier transforms have only real zeros. The characterisation is given in terms of Wronskians of polynomials that are orthogonal with respect to the measure. The results show that Fourier transforms of a rather general class of measures can be approximated by symmetrized Slater determinants composed by orthogonal polynomials, that is, by some wave functions which are symmetric like the Boson ones. Brief comments on possible interpretation and applications of the main results in quantum and statistical mechanics, to Toda lattices and the general solution of the heat equation, are given. We discuss briefly the possibility of represent the Riemann $\\xi$ function as a partition function of a statistical mechanics system.

Dimitar K. Dimitrov

2013-11-04

37

Functional evolution of quantum cylindrical waves  

E-print Network

Kucha{\\v{r}} showed that the quantum dynamics of (1 polarization) cylindrical wave solutions to vacuum general relativity is determined by that of a free axially-symmetric scalar field along arbitrary axially-symmetric foliations of a fixed flat 2+1 dimensional spacetime. We investigate if such a dynamics can be defined {\\em unitarily} within the standard Fock space quantization of the scalar field. Evolution between two arbitrary slices of an arbitrary foliation of the flat spacetime can be built out of a restricted class of evolutions (and their inverses). The restricted evolution is from an initial flat slice to an arbitrary (in general, curved) slice of the flat spacetime and can be decomposed into (i) `time' evolution in which the spatial Minkowskian coordinates serve as spatial coordinates on the initial and the final slice, followed by (ii) the action of a spatial diffeomorphism of the final slice on the data obtained from (i). We show that although the functional evolution of (i) is unitarily implemented in the quantum theory, generic spatial diffeomorphisms of (ii) are not. Our results imply that a Tomanaga-Schwinger type functional evolution of quantum cylindrical waves is not a viable concept even though, remarkably, the more limited notion of functional evolution in Kucha{\\v{r}}'s `half parametrized formalism' is well-defined.

Demian H. J. Cho; Madhavan Varadarajan

2006-05-11

38

Why the wave function, of all things?  

E-print Network

There are reasons to doubt that making sense of the wave function (other than as a probability algorithm) will help with the project of making sense of quantum mechanics. The consistency of the quantum-mechanical correlation laws with the existence of their correlata is demonstrated. The demonstration makes use of the fact (which is implied by the indeterminacy principle) that physical space is not partitioned "all the way down," and it requires that the eigenvalue-eigenstate link be replaced by a different interpretive principle, whose implications are explored.

Mohrhoff, Ulrich

2014-01-01

39

Photon wave functions and quantum interference experiments  

E-print Network

We present a general theory to describe two-photon interference, including a formal description of few photon intereference in terms of single-photon amplitudes. With this formalism, it is possible to describe both frequency entangled and separable two-photon interference in terms of single-photon wave functions. Using this description, we address issues related to the physical interpretation of two-photon interference experiments. We include a discussion on how few-photon interference can be interpreted as a bosonic exchange effect, and how this relates to traditional exchange effects with fermions.

G. G. Lapaire; J. E. Sipe

2006-07-02

40

Wave functions of log-periodic oscillators  

SciTech Connect

We use the Lewis and Riesenfeld invariant method [J. Math. Phys. 10, 1458 (1969)] and a unitary transformation to obtain the exact Schroedinger wave functions for time-dependent harmonic oscillators exhibiting log-periodic-type behavior. For each oscillator we calculate the quantum fluctuations in the coordinate and momentum as well as the quantum correlations between the coordinate and momentum. We observe that the oscillator with m=m{sub 0}t/t{sub 0} and {omega}={omega}{sub 0}t{sub 0}/t, which exhibits an exact log-periodic oscillation, behaves as the harmonic oscillator with m and {omega} constant.

Bessa, V.; Guedes, I. [Departamento de Fisica, Universidade Federal do Ceara, Campus do Pici, Fortaleza, CE 60455-760 (Brazil)

2011-06-15

41

Wave functions of log-periodic oscillators  

NASA Astrophysics Data System (ADS)

We use the Lewis and Riesenfeld invariant method [J. Math. Phys. 10, 1458 (1969)], 10.1063/1.1664991 and a unitary transformation to obtain the exact Schrödinger wave functions for time-dependent harmonic oscillators exhibiting log-periodic-type behavior. For each oscillator we calculate the quantum fluctuations in the coordinate and momentum as well as the quantum correlations between the coordinate and momentum. We observe that the oscillator with m = m0t/t0 and ? = ?0t0/t, which exhibits an exact log-periodic oscillation, behaves as the harmonic oscillator with m and ? constant.

Bessa, V.; Guedes, I.

2011-06-01

42

Variational wave functions for homogenous Bose systems  

SciTech Connect

We study variational wave functions of the product form, factorizing according to the wave vectors k, for the ground state of a system of bosons interacting via positive pair interactions with a positive Fourier transform. Our trial functions are members of different orthonormal bases in Fock space. Each basis contains a quasiparticle vacuum state and states with an arbitrary finite number of quasiparticles. One of the bases is that of Valatin and Butler (VB), introduced fifty years ago and parametrized by an infinite set of variables determining Bogoliubov's canonical transformation for each k. In another case, inspired by Nozieres and Saint James the canonical transformation for k=0 is replaced by a shift in the creation/annihilation operators. For the VB basis we prove that the lowest energy is obtained in a state with {approx}{radical}(volume) quasiparticles in the zero mode. The number of k=0 physical particles is of the order of the volume and its fluctuation is anomalously large, resulting in an excess energy. The same fluctuation is normal in the second type of optimized bases, the minimum energy is smaller and is attained in a vacuum state. Associated quasiparticle theories and questions about the gap in their spectrum are also discussed.

Sueto, Andras [Research Institute for Solid State Physics and Optics, Hungarian Academy of Sciences, P. O. Box 49, H-1525 Budapest (Hungary); Szepfalusy, Peter [Research Institute for Solid State Physics and Optics, Hungarian Academy of Sciences, P. O. Box 49, H-1525 Budapest (Hungary); Department of Physics of Complex Systems, Eoetvoes University, H-1117 Budapest (Hungary)

2008-02-15

43

Impulse modelling of wave impact pressures on vertical wall  

Microsoft Academic Search

Breaking waves on coastal structures cause high magnitude impact pressures which may be important for the structural stability. In estimating the impact pressure distribution on the wall, there have been a lot of theoretical and experimental work. The present study is concerned with a theoretical approach which is based on the pressure impulse, to find the impact pressures on vertical

M. Salih Kirkgöz; Mustafa Mamak

2004-01-01

44

String wave function across a Kasner singularity  

SciTech Connect

A collision of orbifold planes in 11 dimensions has been proposed as an explanation of the hot big bang. When the two planes are close to each other, the winding membranes become the lightest modes of the theory, and can be effectively described in terms of fundamental strings in a ten-dimensional background. Near the brane collision, the 11-dimensional metric is a Euclidean space times a 1+1-dimensional Milne universe. However, one may expect small perturbations to lead into a more general Kasner background. In this paper we extend the previous classical analysis of winding membranes to Kasner backgrounds, and using the Hamiltonian equations, solve for the wave function of loops with circular symmetry. The evolution across the singularity is regular, and explained in terms of the excitement of higher oscillation modes. We also show there is finite particle production and unitarity is preserved.

Copeland, Edmund J.; Niz, Gustavo [School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom); Turok, Neil [Perimeter Institute for Theoretical Physics, 31 Caroline Street N, Waterloo, Ontario N2L2Y5 (Canada)

2010-06-15

45

A Hammer-Impact, Aluminum, Shear-Wave Seismic Source  

USGS Publications Warehouse

Near-surface seismic surveys often employ hammer impacts to create seismic energy. Shear-wave surveys using horizontally polarized waves require horizontal hammer impacts against a rigid object (the source) that is coupled to the ground surface. I have designed, built, and tested a source made out of aluminum and equipped with spikes to improve coupling. The source is effective in a variety of settings, and it is relatively simple and inexpensive to build.

Haines, Seth S.

2007-01-01

46

Gap Wave Propagation in Functionally Graded Piezoelectric Material Structures  

E-print Network

Gap Wave Propagation in Functionally Graded Piezoelectric Material Structures Jianke Du, Kai Xian@nbu.edu.cn Abstract-Shear horizontal gap wave propagating between functionally graded piezoelectric material (FGPM-space and a piezoceramic plate were investigated in [3]. A new-style material called functionally graded material (FGM

Wang, Ji

47

Love wave propagation in functionally graded piezoelectric material layer  

E-print Network

Love wave propagation in functionally graded piezoelectric material layer Jianke Du *, Xiaoying Jin is used to investigate Love waves in functionally graded piezoelectric material (FGPM) layer bonded functionally graded material (FGM) was proposed to solve problems in the thermal- protection systems

Wang, Ji

48

Protective measurements of the wave function of a single system  

E-print Network

My view on the meaning of the quantum wave function and its connection to protective measurements is described. The wave function and only the wave function is the ontology of the quantum theory. Protective measurements support this view although they do not provide a decisive proof. A brief review of the discovery and the criticism of protective measurements is presented. Protective measurements with postselection are discussed.

Lev Vaidman

2014-01-26

49

POSSIBLE EXPERIMENTS ON WAVE FUNCTION LOCALIZATION DUE TO COMPTON SCATTERING  

SciTech Connect

The reduction of a particle s wave function in the process of radiation or light scattering is a longstanding problem. Its solution will give a clue on processes that form, for example, wave functions of electrons constantly emitting synchrotron radiation quanta in storage rings. On a more global scale, it may shed light on wave function collapse due to the process of measurement. In this paper we consider various experimental options using Fermilab electron beams and a possible electron beam from the SNS linac and lasers to detect electron wave function change due to Compton scattering.

Aleksandrov, Alexander V [ORNL] [ORNL; Danilov, Viatcheslav V [ORNL] [ORNL; Gorlov, Timofey V [ORNL] [ORNL; Liu, Yun [ORNL] [ORNL; Shishlo, Andrei P [ORNL] [ORNL; Nagaitsev, [FNAL] [FNAL

2013-01-01

50

Holographic Wave Functions, Meromorphization and Counting Rules  

SciTech Connect

We study the large-Q{sup 2} behavior of the meson form factor F{sub M} (Q{sup 2}) constructed using the holographic light-front wave functions proposed recently by Brodsky and de Teramond. We show that this model can be also obtained within the Migdal's regularization approach (''meromorphization''), if one applies it to 3-point function for scalar currents made of scalar quarks. We found that the asymptotic 1/Q{sup 2} behavior of F{sub M} (Q{sup 2}) is generated by soft Feynman mechanism rather than by short distance dynamics, which causes very late onset of the 1/Q{sup 2} asymptotic behavior. It becomes visible only for unaccessible momenta Q{sup 2} {approx}> 10, GeV{sup 2}. Using meromorphization for spin-1/2 quarks, we demonstrated that resulting form factor F{sup spinor}{sub M} (Q{sup 2}) has 1/Q{sup 4} asymptotic behavior. Now, owing to the late onset of this asymptotic pattern, F{sup spinor}{sub M} (Q{sup 2}) imitates the 1/Q{sup 2} behavior in the few GeV{sup 2} region.

Anatoly Radyushkin

2006-05-10

51

Hadronic wave function in quantum chromodynamics  

SciTech Connect

The underlying link between hadronic phenomena in quantum chromodynamics at large and small distance is the hadronic wavefunction. The theoretical and empirical constraints on the hadronic wave-function and hadronic structure functions; the predictions of perturbative QCD for the large transverse momentum tail of the Fock state infinite momentum wavefunction psi (k/sub perpendicular to i/,x/sub i/,s/sub i/); the valence Fock state meson wavefunctions from the meson decay; the evolution equations of the distribution amplitudes; and a simplified model for the basic wavefunctions are presented. In particular, a new type of low energy theorem is obtained for the pion wavefunction from the ..pi../sup 0/ ..-->.. ..gamma gamma... This result, together with the constraint on the valence wavefunction from the ..pi../sup 0/ ..-->.. ..mu nu.. decay, leads to the probability of finding the valence vertical bar q anti q > state. All these constraints allow construction of a possible model which describes hadronic wavefunctions, probability amplitudes, and distributions. Results are compared with data for form factors and the deep inelastic processes. This work represents a first attempt to construct a model of hadronic structure which is consistent with data and QCD at large and small distances.

Brodsky, S.J.; Huang, T.; Lepage, G.P.

1980-01-01

52

Photon wave functions, wave-packet quantization of light, and coherence theory  

Microsoft Academic Search

The monochromatic Dirac and polychromatic Titulaer–Glauber quantized field theories (QFTs) of electromagnetism are derived from a photon-energy wave function in much the same way that one derives QFT for electrons, i.e., by quantization of a single-particle wave function. The photon wave function and its equation of motion are established from the Einstein energy–momentum–mass relation, assuming a local energy density. This

Brian J. Smith; M. G. Raymer

2007-01-01

53

Photon wave functions, wave-packet quantization of light, and coherence theory  

Microsoft Academic Search

The monochromatic Dirac and polychromatic Titulaer Glauber quantized field theories (QFTs) of electromagnetism are derived from a photon-energy wave function in much the same way that one derives QFT for electrons, i.e., by quantization of a single-particle wave function. The photon wave function and its equation of motion are established from the Einstein energy momentum mass relation, assuming a local

Brian J. Smith; M. G. Raymer

2007-01-01

54

Photon wave functions, wave-packet quantization of light, and coherence theory  

E-print Network

The monochromatic Dirac and polychromatic Titulaer-Glauber quantized field theories (QFTs) of electromagnetism are derived from a photon-energy wave function in much the same way that one derives QFT for electrons, that is, by quantization of a single-particle wave function. The photon wave function and its equation of motion are established from the Einstein energy-momentum-mass relation, assuming a local energy density. This yields a theory of photon wave mechanics (PWM). The proper Lorentz-invariant single-photon scalar product is found to be non-local in coordinate space, and is shown to correspond to orthogonalization of the Titulaer-Glauber wave-packet modes. The wave functions of PWM and mode functions of QFT are shown to be equivalent, evolving via identical equations of motion, and completely describe photonic states. We generalize PWM to two or more photons, and show how to switch between the PWM and QFT viewpoints. The second-order coherence tensors of classical coherence theory and the two-photon wave functions are shown to propagate equivalently. We give examples of beam-like states, which can be used as photon wave functions in PWM, or modes in QFT. We propose a practical mode converter based on spectral filtering to convert between wave packets and their corresponding biorthogonal dual wave packets.

Brian J. Smith; M. G. Raymer

2007-08-06

55

Chameleonic equivalence postulate and wave function collapse  

E-print Network

A chameleonic solution to the cosmological constant problem and the non-equivalence of different conformal frames at the quantum level have been recently suggested [Phys. Rev. D82 (2010) 044006]. In this article we further discuss the theoretical grounds of that model and we are led to a chameleonic equivalence postulate (CEP). Whenever a theory satisfies our CEP (and some other additional conditions), a density-dependence of the mass of matter fields is naturally present. Let us summarize the main results of this paper. 1) The CEP can be considered the microscopic counterpart of the Einstein's Equivalence Principle and, hence, a chameleonic description of quantum gravity is obtained: in our model, (quantum) gravitation is equivalent to a conformal anomaly. 2) To illustrate one of the possible applications of the CEP, we point out a connection between chameleon fields and quantum-mechanical wave function collapse. The collapse is induced by the chameleonic nature of the theory. We discuss the collapse for a Stern-Gerlach experiment and for a diffraction experiment with electrons. More research efforts are necessary to verify whether these ideas are compatible with phenomenological constraints.

Andrea Zanzi

2014-04-03

56

Electron wave-functions in a magnetic field  

E-print Network

The problem of a single electron in a magnetic field is revisited from first principles. It is shown that the standard quantization, used by Landau, is inconsistent for this problem, whence Landau's wave functions spontaneously break the gauge symmetry of translations in the plane. Because of this Landau's (and Fock's) wave functions have a spurious second quantum number. The one-body wave function of the physical orbit, with only one quantum number, is derived, and expressed as a superposition of Landau's wave functions. Conversely, it is shown that Landau's wave functions are a limiting case of physical solutions of a different problem, where two quantum numbers naturally appear. When the translation gauge symmetry is respected, the degeneracy related to the choice of orbit center does not appear in the one-body problem.

D. K. Sunko

2011-11-25

57

Wave-particle duality and `bipartite' wave functions for a single particle  

E-print Network

It is shown that `bipartite' wave functions can present a mathematical formalism of quantum theory for a single particle, in which the associated Schr\\"{o}dinger's wave functions correspond to those `bipartite' wave functions of product forms. This extension of Schr\\"{o}dinger's form establishes a mathematical expression of wave-particle duality and that von Neumann's entropy is a quantitative measure of complementarity between wave-like and particle-like behaviors. In particular, this formalism suggests that collapses of Schr\\"{o}dinger's wave functions can be regarded as the simultaneous transition of the particle from many levels to one. Our results shed considerable light on the basis of quantum mechanics, including quantum measurement.

Zeqian Chen

2006-09-12

58

Effect of Forcing Function on Nonlinear Acoustic Standing Waves  

NASA Technical Reports Server (NTRS)

Nonlinear acoustic standing waves of high amplitude have been demonstrated by utilizing the effects of resonator shape to prevent the pressure waves from entering saturation. Experimentally, nonlinear acoustic standing waves have been generated by shaking an entire resonating cavity. While this promotes more efficient energy transfer than a piston-driven resonator, it also introduces complicated structural dynamics into the system. Experiments have shown that these dynamics result in resonator forcing functions comprised of a sum of several Fourier modes. However, previous numerical studies of the acoustics generated within the resonator assumed simple sinusoidal waves as the driving force. Using a previously developed numerical code, this paper demonstrates the effects of using a forcing function constructed with a series of harmonic sinusoidal waves on resonating cavities. From these results, a method will be demonstrated which allows the direct numerical analysis of experimentally generated nonlinear acoustic waves in resonators driven by harmonic forcing functions.

Finkheiner, Joshua R.; Li, Xiao-Fan; Raman, Ganesh; Daniels, Chris; Steinetz, Bruce

2003-01-01

59

Impact of insomnia on future functioning of adolescents  

Microsoft Academic Search

Objective: To examine the impact of insomnia among adolescents on somatic, interpersonal, and psychological functioning using data from a two-wave, prospective study. Methods: Subjects were adolescents 11–17 years of age sampled from managed care enrollment rosters in the United States. The baseline sample was 4175 and the follow-up sample a year later was 3136. Data were collected using computer-assisted personal

Robert E Roberts; Catherine Ramsay Roberts; Irene Ger Chen

2002-01-01

60

An Experimental and Computational Study of Breaking Wave Impact Forces  

E-print Network

The impact forces generated by the impact of a breaking wave are poorly understood. These impulsive hydrodynamic loads to a ship's hull are of short duration relative to ship motions and buoyant wave loads and often result in extremely high pressures. The physics of breaking waves is a poorly understood, complex, multiphase phenomenon involving violent jet sprays, strong free-surface turbulence, air entrainment and bubble generation, all of which interact with the flow field and the adjacent structure. This paper will describe a set of experiments that were performed, at the Naval Surface Warfare Center, Carderock Division (NSWCCD), in 2006, to measure the hydrodynamic loads of regular nonbreaking and focused breaking waves on a 0.305 m x 0.305 m (1.0 ft x 1.0 ft) square plate and discuss the results of this study. The paper will also discuss Computational Fluid Dynamics (CFD) code predictions of breaking waves and wave impact loads. The CFD code utilized in this study is Numerical Flow Analysis (NFA).

Fu, Thomas C; Brewton, Susan; Brucker, Kyle A; Dommermuth, Douglas G

2014-01-01

61

Heat waves in urban heat islands: interactions, impacts, and mitigation  

NASA Astrophysics Data System (ADS)

Urbanization rates and the intensity of anthropogenic global warming are both on the rise. By the middle of this century, climate change impacts on humans will be largely manifested in urban regions and will result from a combination of global to regional impacts related to greenhouse gas emissions, as well as regional to local impacts related to land-cover changes associated with urbanization. Alarmingly, our understanding of how these two distinct impacts will interact remains very poor. One example, which is the focus of this study, is the interaction of urban heat islands and heat waves. Urban heat islands (UHIs) are spatial anomalies consisting of higher temperatures over built terrain; while their intensity varies with many factors, it consistently increases with city size. UHIs will hence intensify in the future as cities expand. Heat waves are temporal anomalies in the regional temperatures that affect both urban and rural areas; there is high certainty that the frequency and intensity of such waves will increase as a result global warming. However, whether urban and rural temperatures respond in the same way to heat waves remains a critical unanswered question. In this study, a combination of observational and modeling analyses of a heat wave event over the Baltimore-Washington urban corridor reveals synergistic interactions between urban heat islands and heat waves. Not only do heat waves increase the regional temperatures, but they also intensify the difference between urban and rural temperatures. That is, their impact is stronger in cities and the urban heat stress during such waves is larger than the sum of the background urban heat island effect and the heat wave effect. We also develop a simple analytical model of this interaction that suggests that this exacerbated impact in urban areas is primarily to the lack of surface moisture, with low wind speeds also playing a smaller role. Finally, the effectiveness of cool and green roofs as UHI mitigation strategies during intense heat waves are evaluated at city scales. These strategies are shown to reduce urban surface temperatures in the Baltimore-Washington corridor by about 5 K and urban air temperatures by about 1 K. These reductions are most significant in the dense urban cores of the two cities, but they are not sufficient to fully offset the UHI effect.

Bou-Zeid, E.; Li, D.

2013-12-01

62

Physical measurements of breaking wave impact on a floating wave energy converter  

NASA Astrophysics Data System (ADS)

Marine energy converter must both efficiently extract energy in small to moderate seas and also successfully survive storms and potential collisions. Extreme loads on devices are therefore an important consideration in their design process. X-MED is a SuperGen UKCMER project and is a collaboration between the Universities of Manchester, Edinburgh and Plymouth and the Scottish Association for Marine Sciences. Its objective is to extend the knowledge of extreme loads due to waves, currents, flotsam and mammal impacts. Plymouth Universities contribution to the X-MED project involves measuring the loading and response of a taut moored floating body due to steep and breaking wave impacts, in both long crested and directional sea states. These measurements are then to be reproduced in STAR-CCM+, a commercial volume of fluid CFD solver, so as to develop techniques to predict the wave loading on wave energy converters. The measurements presented here were conducted in Plymouth Universities newly opened COAST laboratories 35m long, 15.5m wide and 3m deep ocean basin. A 0.5m diameter taut moored hemispherical buoy was used to represent a floating wave energy device or support structure. The changes in the buoys 6 degree of freedom motion and mooring loads are presented due to focused breaking wave impacts, with the breaking point of the wave changed relative to the buoy.

Hann, Martyn R.; Greaves, Deborah M.; Raby, Alison

2013-04-01

63

Electronic wave functions of quasiperiodic systems in momentum space  

NASA Astrophysics Data System (ADS)

In quasicrystalline tilings often multifractal electronic wave functions can be found. In order to obtain a better insight into their localization properties, we study the wave functions of quasiperiodic tilings in momentum space. The models are based on one-dimensional quasiperiodic chains, in which the atoms are coupled by weak and strong bonds aligned according to the metallic-mean sequences. The associated hypercubic tilings and labyrinth tilings in d dimensions are then constructed from the direct product of d such chains. The results show that each wave function is described by a hierarchy of wave vectors and is always dominated by a single wave vector which is directly related to the energy eigenvalue of the wave function. The corresponding spectral function of the systems shows a hierarchy of branches with different intensities. Each branch is a copy of the main branch containing the dominant wave vectors for each wave function. Using perturbation theory and a renormalization group approach, we determine the shape of the branches for the limit of weak and strong coupling.

Rolof, Sebastian; Thiem, Stefanie; Schreiber, Michael

2013-09-01

64

Sudden impact probing submicrosecond shock waves  

Microsoft Academic Search

Analysis of high-impact loading is essential in basic materials science; applications range from the protection of spacecraft from meteoroids and the design of advanced weaponry and armor to the safety engineering of nuclear reactors and the explosive forming and welding of metals. Shock-compression science and engineering has undergone a steady growth since World War II. The instruments, devices, and gauges

L. C. Chhabildas; R. A. Graham

1988-01-01

65

Dark energy from quantum wave function collapse of dark matter  

E-print Network

Dynamical wave function collapse models entail the continuous liberation of a specified rate of energy arising from the interaction of a fluctuating scalar field with the matter wave function. We consider the wave function collapse process for the constituents of dark matter in our universe. Beginning from a particular early era of the universe chosen from physical considerations, the rate of the associated energy liberation is integrated to yield the requisite magnitude of dark energy around the era of galaxy formation. Further, the equation of state for the liberated energy approaches $w \\to -1$ asymptotically, providing a mechanism to generate the present acceleration of the universe.

A. S. Majumdar; D. Home; S. Sinha

2005-06-22

66

Pole wave-function renormalization prescription for unstable particles  

E-print Network

We base a new wave-function renormalization prescription on the pole mass renormalization prescription, in which the Wave-function Renormalization Constant (WRC) is extracted by expanding the particle's propagator around its pole, rather than its physical mass point as convention. We find the difference between the new and the conventional WRC is gauge-parameter dependent for unstable particles beyond one-loop level, which will lead to some physical results gauge dependent under the conventional wave-function renormalization prescription beyond one-loop level.

Yong Zhou

2005-10-19

67

Impact of Fog on Electromagnetic Wave Propagation  

NASA Astrophysics Data System (ADS)

This experiment was designed to explore the impact of fog on electromagnetic radiation, in particular microwaves and infrared light. For years law enforcement agencies have used microwave radiation (radar guns) to measure the speed of vehicles, and the last ten years has seen increased use of LIDAR, which uses 905-nm infrared radiation rather than microwaves. To evaulate the effect of fog on the operation of these devices, we have constructed a fog chamber with microwave and optical portals to allow light from a HeNe laser and 10.6-GHz microwaves to propagate through various densities of fog. Data is acquired using Vernier Logger Pro and analyzed using MATLAB and Mathematica. Using the attenuation of the laser light to determine fog density, the impact of fog on the signal-to-noise ratio of both microwave and IR devices may be quantified, and the maximum useful range may be calculated.

Morris, Jonathon; Fleisch, Daniel

2002-04-01

68

Angular correlation function and scattering coefficient of electromagnetic waves  

E-print Network

Angular correlation function and scattering coefficient of electromagnetic waves scattered Engineering, Box 352500, University of Washington, Seattle, Washington 98195-2500 Kyung Pak Jet Propulsion We study three-dimensional (3-D) electromagnetic wave scattering from a buried object under a two

Zhang, Guifu

69

Pain's Impact on Adaptive Functioning  

ERIC Educational Resources Information Center

Background: Pain interferes with the functioning of typical children, but no study has examined its effect on children with pre-existing intellectual disabilities (ID). Methods: Caregivers of 63 children observed their children for 2-h periods and recorded in 1-week diaries: pain presence, cause, intensity and duration. Caregivers also recorded…

Breau, L. M.; Camfield, C. S.; McGrath, P. J.; Finley, G. A.

2007-01-01

70

Sign problem of the fermionic shadow wave function  

NASA Astrophysics Data System (ADS)

We present a whole series of methods to alleviate the sign problem of the fermionic shadow wave function in the context of variational Monte Carlo. The effectiveness of our techniques is demonstrated on liquid 3He. We found that although the variance is reduced, the gain in efficiency is restricted by the increased computational cost. Yet, this development not only extends the scope of the fermionic shadow wave function, but also facilitates highly accurate quantum Monte Carlo simulations previously thought not feasible.

Calcavecchia, Francesco; Pederiva, Francesco; Kalos, Malvin H.; Kühne, Thomas D.

2014-11-01

71

Asymptotic scattering wave function for three charged particles and astrophysical capture processes  

E-print Network

The asymptotic behavior of the wave functions of three charged particles has been investigated. There are two different types of three-body scattering wave functions. The first type of scattering wave function evolves from the incident three...

Pirlepesov, Fakhriddin

2006-08-16

72

Uniform WKB approximation of Coulomb wave functions for arbitrary partial wave  

E-print Network

Coulomb wave functions are difficult to compute numerically for extremely low energies, even with direct numerical integration. Hence, it is more convenient to use asymptotic formulas in this region. It is the object of this paper to derive analytical asymptotic formulas valid for arbitrary energies and partial waves. Moreover, it is possible to extend these formulas for complex values of parameters.

N. Michel

2008-12-12

73

Underwater Mach wave radiation from impact pile driving: theory and observation.  

PubMed

The underwater noise from impact pile driving is studied using a finite element model for the sound generation and parabolic equation model for propagation. Results are compared with measurements using a vertical line array deployed at a marine construction site in Puget Sound. It is shown that the dominant underwater noise from impact driving is from the Mach wave associated with the radial expansion of the pile that propagates down the pile after impact at supersonic speed. The predictions of vertical arrival angle associated with the Mach cone, peak pressure level as function of depth, and dominant features of the pressure time series compare well with corresponding field observations. PMID:21895063

Reinhall, Per G; Dahl, Peter H

2011-09-01

74

Matter Density and Relativistic Models of Wave Function Collapse  

E-print Network

Mathematical models for the stochastic evolution of wave functions that combine the unitary evolution according to the Schroedinger equation and the collapse postulate of quantum theory are well understood for non-relativistic quantum mechanics. Recently, there has been progress in making these models relativistic. But even with a fully relativistic law for the wave function evolution, a problem with relativity remains: Different Lorentz frames may yield conflicting values for the matter density at a space-time point. We propose here a relativistic law for the matter density function. According to our proposal, the matter density function at a space-time point x is obtained from the wave function psi on the past light cone of x by setting the i-th particle position in |psi|^2 equal to x, integrating over the other particle positions, and averaging over i. We show that the predictions that follow from this proposal agree with all known experimental facts.

Daniel Bedingham; Detlef Duerr; GianCarlo Ghirardi; Sheldon Goldstein; Roderich Tumulka; Nino Zanghi

2011-11-06

75

Parametric dependence of ocean wave-radar modulation transfer functions  

NASA Technical Reports Server (NTRS)

Microwave techniques at X and L band were used to determine the dependence of ocean-wave radar modulation transfer functions (MTFs) on various environmental and radar parameters during the Marine Remote Sensing experiment of 1979 (MARSEN 79). These MIF are presented, as are coherence functions between the AM and FM parts of the backscattered microwave signal. It is shown that they both depend on several of these parameters. Besides confirming many of the properties of transfer functions reported by previous authors, indications are found that MTFs decrease with increasing angle between wave propagation and antenna-look directions but are essentially independent of small changes in air-sea temperature difference. However, coherence functions are much smaller when the antennas are pointed perpendicular to long waves. It is found that X band transfer functions measured with horizontally polarized microwave radiation have larger magnitudes than those obtained by using vertical polarization.

Plant, W. J.; Keller, W. C.; Cross, A.

1983-01-01

76

Improved WKB radial wave functions in several bases  

SciTech Connect

We develop approximate WKB-like solutions to the radial Schroedinger equation for problems with an angular momentum barrier using Riccati-Bessel, Coulomb, and harmonic-oscillator functions as basis functions. The solutions treat the angular momentum singularity near the origin more accurately in leading approximation than the standard WKB solutions based on sine waves. The solutions based on Riccati-Bessel and free Coulomb wave functions continue smoothly through the inner turning point and are appropriate for scattering problems. The solutions based on oscillator and bound Coulomb wave functions incorporate both turning points smoothly and are particularly appropriate for bound-state problems; no matching of piecewise solutions using Airy functions is necessary.

Durand, B.; Durand, L.

1986-05-01

77

Spectroscopic measurement of an atomic wave function  

E-print Network

that the height of the peaks for the filter function at the values of x5xn 6 are independent of x. The filter function F(x ,dk) can therefore be approximated, apart from a trivial factor, by d functions at these points. As a result, we can simplify Eq. ~9... (x)u at the points x5xn6 . Note that the normalization fac- tor is modified to N 8 to incorporate the trivial multiplicative factors arising after the introduction of the Kronecker delta symbols for the filter function. In the next set...

Kapale, KT; Qamar, S.; Zubairy, M. Suhail.

2003-01-01

78

Wave Impact Study on a Residential Building Wave Impact Study on a Residential Building  

E-print Network

Subduction Zone (CSZ) fault runs from Northern California to British Columbia and is less than 100 miles. W. et al. Fig. 2. Cascadia subduction , result in waves that can interact with residential coastal structures. In the United States, the Cascadia

Cox, Dan

79

Rapidity resummation for $B$-meson wave functions  

E-print Network

Transverse-momentum dependent (TMD) hadronic wave functions develop light-cone divergences under QCD corrections, which are commonly regularized by the rapidity $\\zeta$ of gauge vector defining the non-light-like Wilson lines. The yielding rapidity logarithms from infrared enhancement need to be resummed for both hadronic wave functions and short-distance functions, to achieve scheme-independent calculations of physical quantities. We briefly review the recent progress on the rapidity resummation for $B$-meson wave functions which are the key ingredients of TMD factorization formulae for radiative-leptonic, semi-leptonic and non-leptonic $B$-meson decays. The crucial observation is that rapidity resummation induces a strong suppression of $B$-meson wave functions at small light-quark momentum, strengthening the applicability of TMD factorization in exclusive $B$-meson decays. The phenomenological consequence of rapidity-resummation improved $B$-meson wave functions is further discussed in the context of $B \\to \\pi$ transition form factors at large hadronic recoil.

Yue-Long Shen; Yu-Ming Wang

2014-09-03

80

Stress Wave Source Characterization: Impact, Fracture, and Sliding Friction  

E-print Network

the focal mechanisms and time-histories of these stress wavestress wave sources are explored. Force-time functions and focal mechanismsfocal mechanisms, source time history (f(t)), and absolute amplitude of the force redistribution required to generate these high frequency stress

McLaskey, Gregory Christofer

2011-01-01

81

Wave functions of bosonic symmetry protected topological phases  

NASA Astrophysics Data System (ADS)

We study the structure of the ground-state wave functions of bosonic symmetry protected topological (SPT) insulators in three space dimensions. We demonstrate that the differences with conventional insulators are captured simply in a dual vortex description. As an example, we show that a previously studied bosonic topological insulator with both global U(1) and time-reversal symmetry can be described by a rather simple wave function written in terms of dual “vortex ribbons.” The wave function is a superposition of all the vortex-ribbon configurations of the boson, and a factor (-1) is associated with each self-linking of the vortex ribbons. This wave function can be conveniently derived using an effective field theory of the SPT phase in the strong-coupling limit, and it naturally explains all the phenomena of this SPT phase discussed previously. The ground-state structure for other three-dimensional (3D) bosonic SPT phases are also discussed similarly in terms of vortex loop gas wave functions. We show that our methods reproduce known results on the ground-state structure of some 2D SPT phases.

Xu, Cenke; Senthil, T.

2013-05-01

82

Inside looking out: Probing JIMWLK wave functions with BFKL calculations  

SciTech Connect

We investigate the relation between the eigenvalues and eigenfunctions of the Balitsky-Fadin-Kuraev-Lipatov (BFKL) and Jalilian-Marian-Iancu-McLerran-Weigert-Leonidov-Kovner (JIMWLK/KLWMIJ) Hamiltonians. We show that the eigenvalues of the BFKL Hamiltonians are also exact eigenvalues of the KLWMIJ (and JIMWLK) Hamiltonian, albeit corresponding to possibly non-normalizable eigenfunctions. The question whether a given eigenfunction of BFKL corresponds to a normalizable eigenfunction of KLWMIJ is rather complicated, except in some obvious cases, and requires independent investigation. As an example to illustrate this relation we concentrate on the color octet exchange in the framework of KLWMIJ Hamiltonian. We show that it corresponds to the reggeized gluon exchange of BFKL, and find first correction to the BFKL wave function, which has the meaning of the impact factor for shadowing correction to the Reggeized gluon. We also show that the bootstrap condition in the KLWMIJ framework is satisfied automatically and does not carry any additional information to that contained in the second quantized structure of the KLWMIJ Hamiltonian. This is an example of how the bootstrap condition inherent in the t-channel unitarity arises in the s-channel picture.

Altinoluk, Tolga; Kovner, Alex [Physics Department, University of Connecticut, 2152 Hillside Road, Storrs, Connecticut 06269 (United States); Levin, Eugene [Departamento de Fisica, Universidad Tecnica Federico Santa Maria, Avenida Espana 1680, Casilla 110-V, Valparaiso (Chile); Department of Particle Physics, Tel Aviv University, Tel Aviv 69978 (Israel)

2010-10-01

83

Impact of rheumatoid arthritis on sexual function  

PubMed Central

Sexuality is a complex aspect of the human being’s life and is more than just the sexual act. Normal sexual functioning consists of sexual activity with transition through the phases from arousal to relaxation with no problems, and with a feeling of pleasure, fulfillment and satisfaction. Rheumatic diseases may affect all aspects of life including sexual functioning. The reasons for disturbing sexual functioning are multifactorial and comprise disease-related factors as well as therapy. Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease characterized by progressive joint destruction resulting from chronic synovial inflammation. It leads to various degrees of disability, and ultimately has a profound impact on the social, economic, psychological, and sexual aspects of the patient’s life. This is a systemic review about the impact of RA on sexual functioning. PMID:24829873

Tristano, Antonio G

2014-01-01

84

Wave function for smooth potential and mass step  

Microsoft Academic Search

The one-dimensional Schrödinger equation, derived from the general form of the effective-mass Hamiltonian (metapm?pmrho+mrhopm?pmeta)\\/4+V with eta+?+rho=-1, is solved exactly for a system with smooth potential and mass step. The wave function depends on the Heun function, which is a generalization of the hypergeometric function. The effective-mass Hamiltonian and the connection rules for a system with abrupt heterojunction are deduced from

Liès Dekar; Lyazid Chetouani; Théophile F. Hammann

1999-01-01

85

B meson wave function in k{sub T} factorization  

SciTech Connect

We study the asymptotic behavior of the B meson wave function in the framework of k{sub T} factorization theorem. We first construct a definition of the k{sub T}-dependent B meson wave function, which is free of light-cone divergences. Next-to-leading-order corrections are then calculated based on this definition. The treatment of different types of logarithms in the above corrections, including the Sudakov logarithms, and those depending on a renormalization scale and on an infrared regulator, is summarized. The criticism raised in the literature on our resummation formalism and Sudakov effect is responded. We show that the B meson wave function remains normalizable after taking into account renormalization-group evolution effects, contrary to the observation derived in the collinear factorization theorem.

Li Hsiangnan [Institute of Physics, Academia Sinica, Taipei, Taiwan 115 (China); Department of Physics, National Cheng-Kung University, Tainan, Taiwan 701 (China); Liao, Huei-Shih [Institute of Physics, Academia Sinica, Taipei, Taiwan 115 (China)

2004-10-01

86

Wave propagation of functionally graded material plates in thermal environments.  

PubMed

The wave propagation of an infinite functionally graded plate in thermal environments is studied using the higher-order shear deformation plate theory. The thermal effects and temperature-dependent material properties are both taken into account. The temperature field considered is assumed to be a uniform distribution over the plate surface and varied in the thickness direction only. Material properties are assumed to be temperature-dependent, and graded in the thickness direction according to a simple power law distribution in terms of the volume fractions of the constituents. Considering the effects of transverse shear deformation and rotary inertia, the governing equations of the wave propagation in the functionally graded plate are derived by using the Hamilton's principle. The analytic dispersion relation of the functionally graded plate is obtained by solving an eigenvalue problem. Numerical examples show that the characteristics of wave propagation in the functionally graded plate are relates to the volume fraction index and thermal environment of the functionally graded plate. The influences of the volume fraction distributions and temperature on wave propagation of functionally graded plate are discussed in detail. The results carried out can be used in the ultrasonic inspection techniques and structural health monitoring. PMID:21663930

Sun, Dan; Luo, Song-Nan

2011-12-01

87

Evolution of wave function in a dissipative system  

NASA Technical Reports Server (NTRS)

For a dissipative system with Ohmic friction, we obtain a simple and exact solution for the wave function of the system plus the bath. It is described by the direct product in two independent Hilbert space. One of them is described by an effective Hamiltonian, the other represents the effect of the bath, i.e., the Brownian motion, thus clarifying the structure of the wave function of the system whose energy is dissipated by its interaction with the bath. No path integral technology is needed in this treatment. The derivation of the Weisskopf-Wigner line width theory follows easily.

Yu, Li-Hua; Sun, Chang-Pu

1994-01-01

88

Many-body wave function in a dipole blockade configuration  

SciTech Connect

We report the results of simulations of the many atom wave function when a cold gas is excited to highly excited states. We simulated the many body wave function by direct numerical solution of Schroedinger's equation. We investigated the fraction of atoms excited and the correlation of excited atoms in the gas for different types of excitation when the blockade region was small compared to the sample size. We also investigated the blockade effect when the blockade region is comparable to the sample size to determine the sensitivity of this system and constraints for quantum information.

Robicheaux, F.; Hernandez, J. V. [Department of Physics, Auburn University, Alabama 36849-5311 (United States)

2005-12-15

89

Compressive Direct Measurement of the Quantum Wave Function  

NASA Astrophysics Data System (ADS)

The direct measurement of a complex wave function has been recently realized by using weak values. In this Letter, we introduce a method that exploits sparsity for the compressive measurement of the transverse spatial wave function of photons. The procedure involves weak measurements of random projection operators in the spatial domain followed by postselection in the momentum basis. Using this method, we experimentally measure a 192-dimensional state with a fidelity of 90% using only 25 percent of the total required measurements. Furthermore, we demonstrate the measurement of a 19 200-dimensional state, a task that would require an unfeasibly large acquiring time with the standard direct measurement technique.

Mirhosseini, Mohammad; Magaña-Loaiza, Omar S.; Hashemi Rafsanjani, Seyed Mohammad; Boyd, Robert W.

2014-08-01

90

Can the wave function in configuration space be replaced by single-particle wave functions in physical space?  

E-print Network

The ontology of Bohmian mechanics includes both the universal wave function (living in 3N-dimensional configuration space) and particles (living in ordinary 3-dimensional physical space). Proposals for understanding the physical significance of the wave function in this theory have included the idea of regarding it as a physically-real field in its 3N-dimensional space, as well as the idea of regarding it as a law of nature. Here we introduce and explore a third possibility in which the configuration space wave function is simply eliminated -- replaced by a set of single-particle pilot-wave fields living in ordinary physical space. Such a re-formulation of the Bohmian pilot-wave theory can exactly reproduce the statistical predictions of ordinary quantum theory. But this comes at the rather high ontological price of introducing an infinite network of interacting potential fields (living in 3-dimensional space) which influence the particles' motion through the pilot-wave fields. We thus introduce an alternativ...

Norsen, Travis; Oriols, Xavier

2014-01-01

91

Impact of an oblique breaking wave on a wall  

E-print Network

The intention of this paper is to study impact force of an oblique-angled slamming wave acting on a rigid wall. In the present study the analytical approach is pursued based on a technique proposed by the author. A nonlinear theory in the context of potential flow is presented for determining accurately the free-surface profiles immediately after an oblique breaking wave impingement on the rigid vertical wall that suddenly starts from rest. The small-time expansion is taken as far as necessary to include the accelerating effect. The analytical solutions for the free-surface elevation are derived up to the third order. The results derived in this paper are of particular interest to the marine and offshore engineering industries, which will find the information useful for the design of ships, coastal and offshore.

Shu, Jian-Jun

2014-01-01

92

Water waves of asteroid impact in the lakes  

NASA Astrophysics Data System (ADS)

Meteorite fall occurred in Chelyabinsk (Russia) on February 15, 2013 results a damage in Chelyabink and nearest villages, 1613 injured. The eruption energy is estimated in 600 kilotons of TNT. One of the big fragments up to 650 kg falls in the Chebarkul Lake covered by ice with thickness of 70 cm. The diameter of the hole in ice is 7-8 m. Maximal depth of the lake is 13.5 m and its square is 19.8 km^2. This event pays attention to the possible waves of the asteroid origin in water basins. Known theories of generation of water waves are applied to estimate the hazardous parameters of the meteorite impact in the lakes.

Antonov, Roman; Pelinovsky, Efim

2014-05-01

93

Interrupted fluorescence, quantum jumps, and wave-function collapse  

Microsoft Academic Search

The phenomenon of antibunching provides important support for the physical principle of the collapse of the wave function following a detection of a photon. In this paper it is shown that interrupted fluorescence in a three-level, V-configuration atom, with one transition strongly driven and one weakly driven, can be regarded as evidence supporting the complementary principle of 'collapse by nondetection'.

D. T. Pegg; P. L. Knight

1988-01-01

94

Bohmian Mechanics and the Meaning of the Wave Function  

E-print Network

Bohmian Mechanics and the Meaning of the Wave Function D. D¨urr Mathematisches Institut der predictive successes, quantum mechanics has, since its inception some seventy years ago, been plagued the measurement problem is not merely one of the conceptual difficulties of quantum mechanics

Goldstein, Sheldon

95

SH SURFACE ACOUSTIC WAVE PROPAGATION IN FUNCTIONALLY GRADED PIEZOELECTRIC MATERIAL STRUCTURE WITH DISSIPATION  

E-print Network

477 SH SURFACE ACOUSTIC WAVE PROPAGATION IN FUNCTIONALLY GRADED PIEZOELECTRIC MATERIAL STRUCTURE of functionally graded piezoelectric material (FGPM) on the dispersive and attenuated characteristics of SH. Keywords: SH wave, functionally graded, viscous, dissipation, dispersion relations 315211 818 xiankai

Wang, Ji

96

Wave Function Orthogonality in Relativistic Nucleon Knockout Reactions  

NASA Astrophysics Data System (ADS)

Nucleon knockout reactions such as (e,e'N) and (?,N) are usually treated using the Distorted Wave Impulse Approximation (DWIA). The standard DWIA amplitude suffers from an orthogonality defect which results from the use of nucleon continuum and bound state wave functions that belong to different Hamiltonians. In the past this problem has been discussed mainly within the framework of a nonrelativistic calculation of the amplitude. In the present work, we study the effect of nonorthogonality in the relativistic treatment of the above reactions. The continuum nucleon wave function is made orthogonal to the relevant bound states using the Gram-Schmidt procedure.The orthogonality effects are found to be negligible for (e,e'p) reactions for missing momenta up to 700 MeV/c,for all the three standard coplanar kinematics. By contrast the orthogonalization of the wave functions appears to have a more pronounced effect in the case of (?,p) reactions, particularly at large angles. For these reactions, the spin dependent observables show more sensitivity than the cross sections.

Sherif, H. S.; Johansson, J. I.

1999-10-01

97

Wave distribution functions estimation of VLF electromagnetic waves observed onboard Geos 1  

Microsoft Academic Search

Two methods to determine the electromagnetic wave distribution function are presented. The first is based on the use of the Dirichlet kernels and provides a local average. It has the disadvantage, however, of a nonsystematic approach to positive solutions. The second uses the maximum entropy concept. It leads to particular solutions that are smooth and positive everywhere. The two methods

F. Lefeuvre; M. Parrot; C. Delannoy

1981-01-01

98

Computation of correlation functions and wave function projections in the context of quantum trajectory dynamics  

NASA Astrophysics Data System (ADS)

The de Broglie-Bohm formulation of the Schrödinger equation implies conservation of the wave function probability density associated with each quantum trajectory in closed systems. This conservation property greatly simplifies numerical implementations of the quantum trajectory dynamics and increases its accuracy. The reconstruction of a wave function, however, becomes expensive or inaccurate as it requires fitting or interpolation procedures. In this paper we present a method of computing wave packet correlation functions and wave function projections, which typically contain all the desired information about dynamics, without the full knowledge of the wave function by making quadratic expansions of the wave function phase and amplitude near each trajectory similar to expansions used in semiclassical methods. Computation of the quantities of interest in this procedure is linear with respect to the number of trajectories. The introduced approximations are consistent with approximate quantum potential dynamics method. The projection technique is applied to model chemical systems and to the H +H2 exchange reaction in three dimensions.

Garashchuk, Sophya

2007-04-01

99

Computation of correlation functions and wave function projections in the context of quantum trajectory dynamics.  

PubMed

The de Broglie-Bohm formulation of the Schrodinger equation implies conservation of the wave function probability density associated with each quantum trajectory in closed systems. This conservation property greatly simplifies numerical implementations of the quantum trajectory dynamics and increases its accuracy. The reconstruction of a wave function, however, becomes expensive or inaccurate as it requires fitting or interpolation procedures. In this paper we present a method of computing wave packet correlation functions and wave function projections, which typically contain all the desired information about dynamics, without the full knowledge of the wave function by making quadratic expansions of the wave function phase and amplitude near each trajectory similar to expansions used in semiclassical methods. Computation of the quantities of interest in this procedure is linear with respect to the number of trajectories. The introduced approximations are consistent with approximate quantum potential dynamics method. The projection technique is applied to model chemical systems and to the H+H(2) exchange reaction in three dimensions. PMID:17461611

Garashchuk, Sophya

2007-04-21

100

Helicon Wave Physics Impacts on Electrodeless Thruster Design  

NASA Technical Reports Server (NTRS)

Effective generation of helicon waves for high density plasma sources is determined by the dispersion relation and plasma power balance. Helicon wave plasma sources inherently require an applied magnetic field of .01-0.1 T, an antenna properly designed to couple to the helicon wave in the plasma, and an rf power source in the 10-100 s of MHz, depending on propellant choice. For a plasma thruster, particularly one with a high specific impulse (>2000 s), the physics of the discharge would also have to address the use of electron cyclotron resonance (ECR) heating and magnetic expansion. In all cases the system design includes an optimized magnetic field coil, plasma source chamber, and antenna. A preliminary analysis of such a system, calling on experimental data where applicable and calculations where required, has been initiated at Glenn Research Center. Analysis results showing the mass scaling of various components as well as thruster performance projections and their impact on thruster size are discussed.

Gilland, James

2003-01-01

101

Impact of improved wave dissipation parameterisations on wave-current interactions in a coupled wave-ocean model  

NASA Astrophysics Data System (ADS)

The WAVEWATCH-III model is used operationally as part of the PREVIMER coastal forecast system. A global version of the model provides boundary conditions for a series of stand-alone high-resolution regional sub-domains, on unstructured grids, which are coupled with the regional ocean model MARS. New developments in the WW3 model include a combination of dissipation parameterisations (Ardhuin et al 2010). An anisotropic breaking-induced wind wave dissipation has been based on the local saturation spectrum, with a higher dissipation rate in the mean wave direction, designed to fit observed directional spreading. Additionally, a cumulative dissipation rate inspired by Babanin and Young (2005) but directly estimated from breaking wave probabilities dramatically enhances the dissipation at frequencies greater than 3 times the peak frequency. Regarding swell, a non-linear dissipation based on SAR-derived dissipation rates across the Pacific (Ardhuin et al., 2009) has been introduced. Validation of this model (Rascle and Ardhuin 2012, submitted) using a global hindcast from 1994-2010 shows improvements in significant wave height compared to an altimeter database, with values <10% in general. Regarding extreme events, Hanafin et al (2012) showed that the prediction of the timing of arrival, peak period and spectral distribution of very long swell generated by hurricane-level winds in the North Atlantic compared very well to coastal buoy observations. One of the aims of such improvements is to assist users by providing better geophysical parameters as output. Improvements noted in the mean squared slope compared to buoys, for example, implies a larger amount of energy is available to near-surface Langmuir turbulence. A recent study using the WW3 wave model and the MARS ocean model (Ardhuin et al, in press, JPO 2012) focused on near-shore wave interaction with strong currents. At small scales, rapid steepening of wave slopes by opposing currents induces enhanced breaking as the group velocity decreases. In the study area, tidal currents of up to 4m/s which are highly coherent over the water column and a high wind event created excellent conditions to test the performance of the model. A surface current radar with a resolution of 1km due to multiple signal classification algorithm and a number of buoys were used for validation. Adding currents in the wave model reduced the errors by up to 30% and clearly showed the effects of wave trapping by the strong tidal currents. Comparing different dissipation parameterisations, however, showed that none were completely satisfactory, indicating that further research is required in this area. For short wind waves, the relative wind at the air-sea interface becomes an important factor. At larger scales, waves are refracted by currents. In these cases, the choice of dissipation parameterisation was found to be less important when only one partition was present, though Ardhuin et al (2010) showed better results in mixed seas. Tidal modulations were shown to be due to currents, rather than water level, and a large impact was observed down-wave of currents that have large refraction effects as well as in the vicinity of the currents.

Hanafin, J. A.; Ardhuin, F.; Roland, A.; Leckler, F.; Rascle, N.

2012-12-01

102

Scalar functions for wave extraction in numerical relativity  

E-print Network

Wave extraction plays a fundamental role in the binary black hole simulations currently performed in numerical relativity. Having a well defined procedure for wave extraction, which matches simplicity with efficiency, is critical especially when comparing waveforms from different simulations. Recently, progress has been made in defining a general technique which uses Weyl scalars to extract the gravitational wave signal, through the introduction of the {\\it quasi-Kinnersley tetrad}. This procedure has been used successfully in current numerical simulations; however, it involves complicated calculations. The work in this paper simplifies the procedure by showing that the choice of the {\\it quasi-Kinnersley tetrad} is reduced to the choice of the time-like vector used to create it. The space-like vectors needed to complete the tetrad are then easily identified, and it is possible to write the expression for the Weyl scalars in the right tetrad, as simple functions of the electric and magnetic parts of the Weyl tensor.

Andrea Nerozzi

2007-01-31

103

Acoustic Kappa-Density Fluctuation Waves in Suprathermal Kappa Function Fluids  

E-print Network

We describe a new wave mode similar to the acoustic wave in which both density and velocity fluctuate. Unlike the acoustic wave in which the underlying distribution is Maxwellian, this new wave mode occurs when the underlying distribution is a suprathermal kappa function and involves fluctuations in the power law index, kappa. This wave mode always propagates faster than the acoustic wave with an equivalent effective temperature and becomes the acoustic wave in the Maxwellian limit as kappa goes to infinity.

Michael R. Collier; Aaron Roberts; Adolfo Vinas

2007-10-20

104

Numerical modeling of wave propagation in functionally graded materials using time-domain spectral Chebyshev elements  

NASA Astrophysics Data System (ADS)

Numerical modeling of the Lamb wave propagation in functionally graded materials (FGMs) by a two-dimensional time-domain spectral finite element method (SpFEM) is presented. The high-order Chebyshev polynomials as approximation functions are used in the present formulation, which provides the capability to take into account the through thickness variation of the material properties. The efficiency and accuracy of the present model with one and two layers of 5th order spectral elements in modeling wave propagation in FGM plates are analyzed. Different excitation frequencies in a wide range of 28-350 kHz are investigated, and the dispersion properties obtained by the present model are verified by reference results. The through thickness wave structure of two principal Lamb modes are extracted and analyzed by the symmetry and relative amplitude of the vertical and horizontal oscillations. The differences with respect to Lamb modes generated in homogeneous plates are explained. Zero-crossing and wavelet signal processing-spectrum decomposition procedures are implemented to obtain phase and group velocities and their dispersion properties. So it is attested how this approach can be practically employed for simulation, calibration and optimization of Lamb wave based nondestructive evaluation techniques for the FGMs. The capability of modeling stress wave propagation through the thickness of an FGM specimen subjected to impact load is also investigated, which shows that the present method is highly accurate as compared with other existing reference data.

Hedayatrasa, Saeid; Bui, Tinh Quoc; Zhang, Chuanzeng; Lim, Chee Wah

2014-02-01

105

Impact! Chandra Images a Young Supernova Blast Wave  

NASA Astrophysics Data System (ADS)

Two images made by NASA's Chandra X-ray Observatory, one in October 1999, the other in January 2000, show for the first time the full impact of the actual blast wave from Supernova 1987A (SN1987A). The observations are the first time that X-rays from a shock wave have been imaged at such an early stage of a supernova explosion. Recent observations of SN 1987A with the Hubble Space Telescope revealed gradually brightening hot spots from a ring of matter ejected by the star thousands of years before it exploded. Chandra's X-ray images show the cause for this brightening ring. A shock wave is smashing into portions of the ring at a speed of 10 million miles per hour (4,500 kilometers per second). The gas behind the shock wave has a temperature of about ten million degrees Celsius, and is visible only with an X-ray telescope. "With Hubble we heard the whistle from the oncoming train," said David Burrows of Pennsylvania State University, University Park, the leader of the team of scientists involved in analyzing the Chandra data on SN 1987A. "Now, with Chandra, we can see the train." The X-ray observations appear to confirm the general outlines of a model developed by team member Richard McCray of the University of Colorado, Boulder, and others, which holds that a shock wave has been moving out ahead of the debris expelled by the explosion. As this shock wave collides with material outside the ring, it heats it to millions of degrees. "We are witnessing the birth of a supernova remnant for the first time," McCray said. The Chandra images clearly show the previously unseen, shock-heated matter just inside the optical ring. Comparison with observations made with Chandra in October and January, and with Hubble in February 2000, show that the X-ray emission peaks close to the newly discovered optical hot spots, and indicate that the wave is beginning to hit the ring. In the next few years, the shock wave will light up still more material in the ring, and an inward moving, or reverse, shock wave will heat the material ejected in the explosion itself. "The supernova is digging up its own past," said McCray. The observations were made on October 6, 1999, using the Advanced CCD Imaging Spectrometer (ACIS) and the High Energy Transmission Grating, and again on January 17, 2000, using ACIS. Other members of the team were Eli Michael of the University of Colorado; Dr. Una Hwang, Dr. Steven Holt and Dr. Rob Petre of NASA's Goddard Space Flight Center in Greenbelt, MD; Professor Roger Chevalier of the University of Virginia, Charlottesville; and Professors Gordon Garmire and John Nousek of Pennsylvania State University. The results will be published in an upcoming issue of the Astrophysical Journal. The ACIS instrument was built for NASA by the Massachusetts Institute of Technology, Cambridge, and Pennsylvania State University. The High Energy Transmission Grating was built by the Massachusetts Institute of Technology. NASA's Marshall Space Flight Center in Huntsville, AL, manages the Chandra program. TRW, Inc., Redondo Beach, CA, is the prime contractor for the spacecraft. The Smithsonian's Chandra X-ray Center controls science and flight operations from Cambridge, MA. More About SN 1987A Images to illustrate this release and more information on Chandra's progress can be found on the Internet at: http://chandra.harvard.edu/photo/2000/sn1987a/index.html AND http://chandra.nasa.gov More About SN 1987A

2000-05-01

106

Impact loads and wave kinematics on a fixed truncated circular cylinder due to nonlinear waves in a 2-D tank  

E-print Network

between impact loads and kinematics using an asymmetric steep non-breaking wave. The strong nonlinear kinematics in front of the structure may cause forming air pocket. Both expansion and compression of air pocket at high frequency may produce high...

Zou, Jun

2012-06-07

107

Estimation Of The Green Function From Diffuse Coda Waves  

NASA Astrophysics Data System (ADS)

We investigate the conjecture that the correlation of coda records of regional earth- quakes between two stations may provide the Green function between these two sta- tions. This technique has been used extensively in helioseismology to retrieve the acoustic structure of the sun from cross-correlations of acoustic doppler measure- ments. It was also very efficient to measure the acoustic Green function of an alu- minium body from correlations of thermal noise records (Weaver and Lobkis, 2001). The applicability of the cross-correlation technique in seismology is not straightfor- ward for a number of reasons, including absorption and leakage of seismic waves, and the non-random distribution of sources in the studied volume. However, this last lim- itation can be overcome by using diffuse coda waves which sample the whole space. This is one of the reasons why we chose Mexican seismological data as a sample test for this technique since it has been demonstrated that, for records in Mexico, the late coda is made up of multiply scattered waves that verify the principle of equipartition (Shapiro et al., 2000, Hennino et al., 2001). The average crustal structure is also quite well-known in that region from surface waves, making it possible to compute the the- oretical Green function between two stations. We selected 22 regional events (M>4.5) recorded by stations YAIG and PLIG of the Mexican broadband network. 196 cross- correlation functions were then computed between the records of coda waves at the two stations in 100s time-windows. After amplitude normalization and stacking, we see a clear 8s-period pulse emerging from the stack. The 9 stacked correlation traces computed from the 3-component records display exactly the same symetries as the theoretical Green tensor, and the arrival time of the pulse is the same as the funda- mental Rayleigh wave. This test seems to prove that it is possible to extract the Green function between 2 stations by stacking cross-correlations computed in the diffuse wavefield making up the coda of regional seismograms. Preliminary tests conducted on noise records at the same couple of stations give similar results although the signal- to-noise ratio is not as good as for coda records.

Campillo, M.; Paul, A.

108

Exploring the Roper wave function in Lattice QCD  

E-print Network

Using a correlation matrix analysis consisting of a variety of smearings, the CSSM Lattice collaboration has successfully isolated states associated with the Roper resonance and other "exotic" excited states such as the $\\Lambda(1405)$ on the lattice at near-physical pion masses. We explore the nature of the Roper by examining the eigenvectors that arise from the variational analysis, demonstrating that the Roper state is dominated by the $\\chi_1$ nucleon interpolator and only poorly couples to $\\chi_2.$ By examining the probability distribution of the Roper on the lattice, we find a structure consistent with a constituent quark model. In particular, the Roper $d$-quark wave function contains a single node consistent with a $2S$ state. A detailed comparison with constituent quark model wave functions is carried out, validating the approach of accessing these states by constructing a variational basis composed of different levels of fermion source and sink smearing.

Waseem Kamleh; Derek B. Leinweber; Dale S. Roberts

2013-12-09

109

Analytical wave functions for atomic quantum-defect theory  

Microsoft Academic Search

We present an exactly solvable effective potential that reproduces atomic spectra in the limit of exact quantum-defect theory, i.e., the limit in which, for a fixed l, the principal quantum number is modified by a constant: n*=n-delta(l). Transition probabilities for alkali atoms are calculated using the analytical wave functions obtained and agree well with accepted values. This allows us to

V. Alan Kostelecký; Michael Martin Nieto

1985-01-01

110

Interaction between light and matter: A photon wave function approach  

E-print Network

The Bialynicki-Birula-Sipe photon wave function formalism is extended to include the interaction between photons and continuous non-absorptive media. When the second quantization of this formalism is introduced, a new way of describing the quantum interactions between light and matter emerges. As an example of application, the quantum state of the twin photons generated by parametric down conversion is obtained in agreement with previous treatments, but with a more intuitive interpretation.

Pablo L. Saldanha; C. H. Monken

2011-06-14

111

Wave Function of the Universe and Its Meaning  

E-print Network

For a FRW-spacetime coupled to an arbitrary real scalar field, we endow the solution space of the associated Wheeler-DeWitt equation with a Hilbert-space structure, construct the observables, and introduce the physical wave functions of the universe that admit a genuine probabilistic interpretation. We also discuss a proposal for the formulation of the dynamics. The approach to quantum cosmology outlined in this article is based on the results obtained within the theory of pseudo-Hermitian operators.

Ali Mostafazadeh

2003-08-11

112

Gravity-related spontaneous wave function collapse in bulk matter  

NASA Astrophysics Data System (ADS)

In the DP-model, gravity-related spontaneous wave function collapses suppress Schrödinger cat states which are conceptually problematic especially for gravity and space-time. We derive the equations of the model for the hydrodynamic-elastic (acoustic) modes in a bulk. Two particular features are discussed: the universal dominance of spontaneous collapses at large wavelengths, and the reduction of spontaneous heating by a slight refinement of the DP-model.

Diósi, Lajos

2014-10-01

113

Pion wave functions and truncation sensitivity of QCD sum rules  

NASA Astrophysics Data System (ADS)

The systematic errors inherent in the QCD sum rule approach to meson wave functions are examined in the context of QCD in 1+1 spacetime dimensions in the large N limit where the theory is exactly solvable. The systematic sensitivity of the sum rules reconstruction of meson wave functions to the input data at large Q2 is studied in this model. We find that the reliable extraction of (a few) higher moments is possible provided a reasonably accurate uniform approximation to the Euclidean correlator over a suitable Q2 range is available, but that the extracted values are particularly sensitive to the balance of lower and higher twist contributions. Underestimates of lower twist contributions or overestimates of the highest twist term may lead to too high values for the second and fourth moments of the pion wave function, suggesting a doubly peaked structure of the Chernyak-Zhitnitsky-type. Lattice discretization is shown to lead to similar distortions in the balance of lower and higher twist terms.

Duncan, A.; Pernice, S.; Schnapka, E.

1997-02-01

114

Joint inversion of receiver function and surface wave dispersion observations  

NASA Astrophysics Data System (ADS)

We implement a method to invert jointly teleseismic P-wave receiver functions and surface wave group and phase velocities for a mutually consistent estimate of earth structure. Receiver functions are primarily sensitive to shear wave velocity contrasts and vertical traveltimes, and surface wave dispersion measurements are sensitive to vertical shear wave velocity averages. Their combination may bridge resolution gaps associated with each individual data set. We formulate a linearized shear velocity inversion that is solved using a damped least-squares scheme that incorporates a priori smoothness constraints for velocities in adjacent layers. The data sets are equalized for the number of data points and physical units in the inversion process. The combination of information produces a relatively simple model with a minimal number of sharp velocity contrasts. We illustrate the approach using noise-free and realistic noise simulations and conclude with an inversion of observations from the Saudi Arabian Shield. Inversion results for station SODA, located in the Arabian Shield, include a crust with a sharp gradient near the surface (shear velocity changing from 1.8 to 3.5kms-1 in 3km) underlain by a 5-km-thick layer with a shear velocity of 3.5kms-1 and a 27-km-thick layer with a shear velocity of 3.8kms-1, and an upper mantle with an average shear velocity of 4.7kms-1. The crust-mantle transition has a significant gradient, with velocity values varying from 3.8 to 4.7kms-1 between 35 and 40km depth. Our results are compatible with independent inversions for crustal structure using refraction data.

Julià, J.; Ammon, C. J.; Herrmann, R. B.; Correig, A. M.

2000-10-01

115

Modelling of tsunami wave run-up, breaking and impact on vertical wall by SPH method  

NASA Astrophysics Data System (ADS)

Accurate predictions of wave run-up and run-down are important for coastal impact assessment of relatively long waves such as tsunami or storm waves. Wave run-up is, however, a complex process involving nonlinear build-up of the wave front, intensive wave breaking and strong turbulent flow, making the numerical approximation challenging. Recent advanced modeling methodologies could help to overcome these numerical challenges. For a demonstration, we study run-up of non-breaking and breaking solitary waves on vertical wall using two methods, the enhanced Smoothed Particle Hydrodynamics (SPH) method and the traditional non-breaking nonlinear model Tunami-N2. The Tunami-N2 model fails to capture the evolution of steep waves at the proximity of breaking that observed in the experiments. Whereas, the SPH method successfully simulate the wave propagation, breaking, impact on structure and the reform and breaking processes of wave run-down. The study also indicates that inadequate approximation of the wave breaking could lead to significant under-predictions of wave height and impact pressure on structures. The SPH model shows potential applications for accurate impact assessments of wave run-up onto coastal structures.

Dao, M. H.; Xu, H.; Chan, E. S.; Tkalich, P.

2013-06-01

116

Computational aspects of the continuum quaternionic wave functions for hydrogen  

NASA Astrophysics Data System (ADS)

Over the past few years considerable attention has been given to the role played by the Hydrogen Continuum Wave Functions (HCWFs) in quantum theory. The HCWFs arise via the method of separation of variables for the time-independent Schrödinger equation in spherical coordinates. The HCWFs are composed of products of a radial part involving associated Laguerre polynomials multiplied by exponential factors and an angular part that is the spherical harmonics. In the present paper we introduce the continuum wave functions for hydrogen within quaternionic analysis ((R)QHCWFs), a result which is not available in the existing literature. In particular, the underlying functions are of three real variables and take on either values in the reduced and full quaternions (identified, respectively, with R3 and R4). We prove that the (R)QHCWFs are orthonormal to one another. The representation of these functions in terms of the HCWFs are explicitly given, from which several recurrence formulae for fast computer implementations can be derived. A summary of fundamental properties and further computation of the hydrogen-like atom transforms of the (R)QHCWFs are also discussed. We address all the above and explore some basic facts of the arising quaternionic function theory. As an application, we provide the reader with plot simulations that demonstrate the effectiveness of our approach. (R)QHCWFs are new in the literature and have some consequences that are now under investigation.

Morais, J.

2014-10-01

117

Measurement of the Pion and Photon Light-Cone Wave Functions by Diffractive Dissociation  

E-print Network

The measurement of the pion light-cone wave function is revisited and results for the Gegenbauer coefficients are presented. Mesurements of the photon electromagnetic and hadronic wave functions are described and results are presented.

Daniel Ashery

2005-11-24

118

Love wave propagation in functionally graded piezoelectric material layer.  

PubMed

An exact approach is used to investigate Love waves in functionally graded piezoelectric material (FGPM) layer bonded to a semi-infinite homogeneous solid. The piezoelectric material is polarized in z-axis direction and the material properties change gradually with the thickness of the layer. We here assume that all material properties of the piezoelectric layer have the same exponential function distribution along the x-axis direction. The analytical solutions of dispersion relations are obtained for electrically open or short circuit conditions. The effects of the gradient variation of material constants on the phase velocity, the group velocity, and the coupled electromechanical factor are discussed in detail. The displacement, electric potential, and stress distributions along thickness of the graded layer are calculated and plotted. Numerical examples indicate that appropriate gradient distributing of the material properties make Love waves to propagate along the surface of the piezoelectric layer, or a bigger electromechanical coupling factor can be obtained, which is in favor of acquiring a better performance in surface acoustic wave (SAW) devices. PMID:17107699

Du, Jianke; Jin, Xiaoying; Wang, Ji; Xian, Kai

2007-03-01

119

Wave-current Interaction and Its Impact on Contaminant Transport Primary Investigator: Meng Xia  

E-print Network

via exacerbated currents, erosion and damage. When waves encounter the near shore current, there canWave-current Interaction and Its Impact on Contaminant Transport Primary Investigator: Meng Xia Co Overview This project is designed to develop a three-dimensional coupled Wave-current model that can

120

Elastic response of floating glacier ice to impact of longperiod ocean waves  

E-print Network

Elastic response of floating glacier ice to impact of longperiod ocean waves O. V. Sergienko1 given rise to the question of whether mechanical coupling with waves in the ocean may provide general question: how ocean waves affect the stress regime of floating ice, and in particular, how ocean

Rodgers, Keith

121

A critical survey of wave propagation and impact in composite materials  

NASA Technical Reports Server (NTRS)

A review of the field of stress waves in composite materials is presented covering the period up to December 1972. The major properties of waves in composites are discussed and a summary is made of the major experimental results in this field. Various theoretical models for analysis of wave propagation in laminated, fiber and particle reinforced composites are surveyed. The anisotropic, dispersive and dissipative properties of stress pulses and shock waves in such materials are reviewed. A review of the behavior of composites under impact loading is presented along with the application of wave propagation concepts to the determination of impact stresses in composite plates.

Moon, F. C.

1973-01-01

122

Pion and photon light-cone wave functions from the instanton vacuum  

Microsoft Academic Search

The leading-twist wave functions of the pion and the photon at a low normalization point are calculated in the effective low-energy theory derived from the instanton vacuum. The pion wave function is found to be close to the asymptotic one, consistent with the recent CLEO measurements. The photon wave function is nonzero at the end points. This different behavior is

V. Yu. Petrov; M. V. Polyakov; R. Ruskov; C. Weiss; K. Goeke

1999-01-01

123

Wave Propagation Experiments On Ballistically Impacted Composite Laminates  

Microsoft Academic Search

The details of the time history of the elastic waves in ballistically im pacted composite laminates have been obtained by using surface and em bedded strain gages. Records show that a very low-amplitude in-plane tensile wave arrives first followed by a medium-amplitude flexural wave and then a high-amplitude flexural wave. Measured and calculated values of wave speeds agree well.

Nobuo Takeda; Robert L. Sierakowski; Lawrence E. Malvern

1981-01-01

124

A Critical Examination of Wind-Wave Spectral Functional Form  

NASA Technical Reports Server (NTRS)

Traditionally, data from random ocean waves are presented in spectral functions. The spectra are the result of Fourier analysis. Fourier spectral analysis has dominated data analysis for, at least, the last hundred years. It has been the standard method for is examining the global amplitude-frequency distributions. Although Fourier transform valid under extremely general conditions, there are some crucial restrictions for the Fourier spectral analysis. The system must be linear, and the data must be stationary- otherwise, the resulting spectrum will make little physical sense. The stationarity requirement is also a common required criterion for most of other available data analysis methods. Nevertheless, few, if any, natural phenomena are linear and stationary. To compound these complications is the imperfection of our probes or numerical schemes the interactions of the imperfect probes even with a perfect linear system can make the final data nonlinear. Furthermore, all the available data are usually of finite duration. Under these conditions, Fourier analysis is of limited use, For lack of alternatives, however, Fourier analysis is still used to process such data. The loose application of Fourier analysis and the insouciant adoption of the stationary and linear assumptions may lead to misleading conclusions. Ocean waves are know to be nonlinear, and the wind system generating the wave field are seldom stationary- As a result, the traditional examination of the spectral form hardly made physical sense. A new method for analyzing nonlinear and nonstationary data has been developed. The key part is the Empirical Mode Decomposition (EMD) method with which any complicated data set can be decomposed into a finite and often small number of Intrinsic Mode Functions (IMF) that serve as the basis of the representation of the data, This decomposition method is adaptive, and, therefore, highly efficient. The IMFs admit well-behaved Hilbert transforms, and yield instantaneous energy and frequency as functions of time that give sharp identifications of imbedded structures. The final presentation of the results is an energy-frequency-time distribution, designated as the Hilbert Spectrum. Among the main conceptual innovations is the introduction of the instantaneous frequencies for complicated data sets, which eliminate the need of spurious harmonics to represent nonlinear and nonstationary signals. The spectral forms of the ocean waves are very different. This new method offers the first physical meaningful view of the wave spectrum. Data from laboratory and field will be presented to illustrate the differences.

Huang, Norden E.; Long, Steven R.

1999-01-01

125

Theory of steady-state plane tunneling-assisted impact ionization waves  

SciTech Connect

The effect of band-to-band and trap-assisted tunneling on the properties of steady-state plane ionization waves in p{sup +}-n-n{sup +} structures is theoretically analyzed. It is shown that such tunneling-assisted impact ionization waves do not differ in a qualitative sense from ordinary impact ionization waves propagating due to the avalanche multiplication of uniformly distributed seed electrons and holes. The quantitative differences of tunneling-assisted impact ionization waves from impact ionization waves are reduced to a slightly different relation between the wave velocity u and the maximum field strength E{sub M} at the front. It is shown that disregarding impact ionization does not exclude the possibility of the existence of tunneling-assisted ionization waves; however, their structure radically changes, and their velocity strongly decreases for the same E{sub M}. A comparison of the dependences u(E{sub M}) for various ionization-wave types makes it possible to determine the conditions under which one of them is dominant. In conclusion, unresolved problems concerning the theory of tunneling-assisted impact ionization waves are discussed and the directions of further studies are outlined.

Kyuregyan, A. S., E-mail: ask@vei.ru [Lenin All-Russian Electrical-Engineering Institute (Russian Federation)

2013-07-15

126

Multi-Determinant Wave-functions in Quantum Monte Carlo  

SciTech Connect

Quantum Monte Carlo methods have received considerable attention over the last decades due to the great promise they have for the direct solution to the many-body Schrodinger equation for electronic systems. Thanks to a low scaling with number of particles, they present one of the best alternatives in the accurate study of large systems and solid state calculations. In spite of such promise, the method has not become popular in the quantum chemistry community, mainly due to the lack of control over the fixed-node error which can be large in many cases. In this article we present the application of large multi-determinant expansions in quantum Monte Carlo, studying its performance with first row dimers and the 55 molecules of the G1 test set. We demonstrate the potential of the wave-function to systematically reduce the fixed-node error in the calculations, achieving chemical accuracy in almost all cases studied. When compared to traditional methods in quantum chemistry, the results show a marked improvement over most methods including MP2, CCSD(T) and DFT with various functionals; in fact the only method able to produce better results is the explicitly-correlated CCSD(T) method with a large basis set. With recent developments in trial wave functions and algorithmic improvements in Quantum Monte Carlo, we are quickly approaching a time where the method can become the standard in the study of large molecular systems and solids.

Morales, Miguel A [Lawrence Livermore National Laboratory (LLNL); Mcminis, Jeremy [University of Illinois, Urbana-Champaign; Clark, Bryan K. [Princeton University; Kim, Jeongnim [ORNL; Scuseria, Gustavo E [Rice University

2012-01-01

127

Impact wave deposits provide new constraints on the location of the K/T boundary impact  

NASA Technical Reports Server (NTRS)

All available evidence is consistent with an impact into oceanic crust terminating the Cretaceous Period. Although much of this evidence is incompatible with an endogenic origin, some investigators still feel that a volcanic origin is possible for the Cretaceous/Tertiary (K/T) boundary clay layers. The commonly cited evidence for a large impact stems from delicate clay layers and their components and the impact site has not yet been found. Impact sites have been suggested all over the globe. The impact is felt to have occurred near North America by: the occurrence of a 2 cm thick ejecta layer only at North American locales, the global variation of shocked quartz grain sizes peaking in North America, the global variation of spinel compositions with most refractory compositions occurring in samples from the Pacific region and possibly uniquely severe plant extinctions in the North American region. The K/T boundary interval was investigated as preserved on the banks of the Brazos River, Texas. The K/T fireball and ejecta layers with associated geochemical anomalies were found interbedded with this sequence which apparently allows a temporal resolution 4 orders of magnitude greater than typical K/T boundary sections. A literature search reveals that such coarse deposits are widely preserved at the K/T boundary. Impact wave deposits have not been found elsewhere on the globe, suggesting the impact occurred between North and South America. The coarse deposits preserved in Deep Sea Drilling Project (DSDP) holes 151-3 suggest the impact occurred nearby. Subsequent tectonism has complicated the picture.

Hildebrand, A. R.; Boynton, W. V.

1988-01-01

128

Relativistic Covariance and Quark-Diquark Wave Functions  

E-print Network

We derive covariant wave functions for hadrons composed of two constituents for arbitrary Lorentz boosts. Focussing explicitly on baryons as quark-diquark systems, we reduce their manifestly covariant Bethe-Salpeter equation to covariant 3-dimensional forms by projecting on the relative quark-diquark energy. Guided by a phenomenological multi gluon exchange representation of covariant confining kernels, we derive explicit solutions for harmonic confinement and for the MIT Bag Model. We briefly sketch implications of breaking the spherical symmetry of the ground state and the transition from the instant form to the light cone via the infinite momentum frame.

M. Dillig

2006-04-24

129

Nonlocal condensates & QCD sum rules for the pion wave function  

Microsoft Academic Search

The QCD-sum-rule calculation of the pion wave function by Chernyak and Zhitnitsky (CZ) implicitly assumes that the correlation length of vacuum fluctuations is large compared to the typical hadronic scale 1\\/{ital m}{sub }, so that one can substitute the original nonlocal objects such as {l_angle}{ital {bar q}}(0){ital q}({ital z}){r_angle} by constant {l_angle}{ital {bar q}}(0){ital q}(0){r_angle}-type values. We outline a formalism

Anatoly Radyushkin; Sergei Mikhailov

1991-01-01

130

Extracting the Green's function from the correlation of coda waves: A derivation based on stationary phase  

E-print Network

seismology, there is no equipartition- ing of energy among surface wave modes because the fun- damental Love in three dimensions, and for elastic surface waves. Passive imaging of the ballistic wave is based passive imaging in crustal seismology by retrieving the surface wave Green's function between

Snieder, Roel

131

Ocean Wave-Radar Modulation Transfer Functions From the West Coast Experiment  

Microsoft Academic Search

Short gravity-capillary waves, the equilibrium, or the steady state excitations of the ocean surface are modulated by longer ocean waves. These short waves are the predominant microwave scatterers on the ocean surface under many viewing conditions so that the modulation is readily measured with CW Doppler radar used as a two-scale wave probe. Modulation transfer functions (the ratio of the

J. W. Wright; W. J. Plant; W. C. Keller; W. L. Jones

1980-01-01

132

Relativistic treatment of pion wave functions in the annihilation pp{yields}{pi}{sup -}{pi}{sup +}  

SciTech Connect

Quark model intrinsic wave functions of highly energetic pions in the reaction pp{yields}{pi}{sup -}{pi}{sup +} are subjected to a relativistic treatment. The annihilation is described in a constituent quark model with A2 and R2 flavor-flux topology, and the annihilated quark-antiquark pairs are in {sup 3}P{sub 0} and {sup 3}S{sub 1} states. We study the effects of pure Lorentz transformations on the antiquark and quark spatial wave functions and their respective spinors in the pion. The modified quark geometry of the pion has considerable impact on the angular dependence of the annihilation mechanisms.

El-Bennich, B.; Kloet, W.M. [Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, Piscataway, New Jersey 08854-8019 (United States)

2004-09-01

133

The impact of heat waves on children's health: a systematic review  

NASA Astrophysics Data System (ADS)

Young children are thought to be particularly sensitive to heat waves, but relatively less research attention has been paid to this field to date. A systematic review was conducted to elucidate the relationship between heat waves and children's health. Literature published up to August 2012 were identified using the following MeSH terms and keywords: "heatwave", "heat wave", "child health", "morbidity", "hospital admission", "emergency department visit", "family practice", "primary health care", "death" and "mortality". Of the 628 publications identified, 12 met the selection criteria. The existing literature does not consistently suggest that mortality among children increases significantly during heat waves, even though infants were associated with more heat-related deaths. Exposure to heat waves in the perinatal period may pose a threat to children's health. Pediatric diseases or conditions associated with heat waves include renal disease, respiratory disease, electrolyte imbalance and fever. Future research should focus on how to develop a consistent definition of a heat wave from a children's health perspective, identifying the best measure of children's exposure to heat waves, exploring sensitive outcome measures to quantify the impact of heat waves on children, evaluating the possible impacts of heat waves on children's birth outcomes, and understanding the differences in vulnerability to heat waves among children of different ages and from different income countries. Projection of the children's disease burden caused by heat waves under climate change scenarios, and development of effective heat wave mitigation and adaptation strategies that incorporate other child protective health measures, are also strongly recommended.

Xu, Zhiwei; Sheffield, Perry E.; Su, Hong; Wang, Xiaoyu; Bi, Yan; Tong, Shilu

2014-03-01

134

Ghost wave-function renormalization in Asymptotically Safe Quantum Gravity  

E-print Network

Motivated by Weinberg's asymptotic safety scenario, we investigate the gravitational renormalization group flow in the Einstein-Hilbert truncation supplemented by the wave-function renormalization of the ghost fields. The latter induces non-trivial corrections to the beta-functions for Newton's constant and the cosmological constant. The resulting ghost-improved phase diagram is investigated in detail. In particular, we find a non-trivial ultraviolet fixed point in agreement with the asymptotic safety conjecture, which also survives in the presence of extra dimensions. In four dimensions the ghost anomalous dimension at the fixed point is $\\eta_c^* = -1.8$, supporting space-time being effectively two-dimensional at short distances.

Kai Groh; Frank Saueressig

2010-01-28

135

Coupling of WRF meteorological model to WAM spectral wave model through sea surface roughness at the Balearic Sea: impact on wind and wave forecasts  

NASA Astrophysics Data System (ADS)

Meteorological models, like WRF, usually describe the earth surface characteristics by tables that are function of land-use. The roughness length (z0) is an example of such approach. However, over sea z0 is modeled by the Charnock (1955) relation, linking the surface friction velocity u*2 with the roughness length z0 of turbulent air flow, z0 = ?-u2* g The Charnock coefficient ? may be considered a measure of roughness. For the sea surface, WRF considers a constant roughness ? = 0.0185. However, there is evidence that sea surface roughness should depend on wave energy (Donelan, 1982). Spectral wave models like WAM, model the evolution and propagation of wave energy as a function of wind, and include a richer sea surface roughness description. Coupling WRF and WAM is thus a common way to improve the sea surface roughness description of WRF. WAM is a third generation wave model, solving the equation of advection of wave energy subject to input/output terms of: wind growth, energy dissipation and resonant non-linear wave-wave interactions. Third generation models work on the spectral domain. WAM considers the Charnock coefficient ? a complex yet known function of the total wind input term, which depends on the wind velocity and on the Charnock coefficient again. This is solved iteratively (Janssen et al., 1990). Coupling of meteorological and wave models through a common Charnock coefficient is operationally done in medium-range met forecasting systems (e.g., at ECMWF) though the impact of coupling for smaller domains is not yet clearly assessed (Warner et al, 2010). It is unclear to which extent the additional effort of coupling improves the local wind and wave fields, in comparison to the effects of other factors, like e.g. a better bathymetry and relief resolution, or a better circulation information which might have its influence on local-scale meteorological processes (local wind jets, local convection, daily marine wind regimes, etc.). This work, within the scope of the 7th EU FP Project FIELD_AC, assesses the impact of coupling WAM and WRF on wind and wave forecasts on the Balearic Sea, and compares it with other possible improvements, like using available high-resolution circulation information from MyOcean GMES core services, or assimilating altimeter data on the Western Mediterranean. This is done in an ordered fashion following statistical design rules, which allows to extract main effects of each of the factors considered (coupling, better circulation information, data assimilation following Lionello et al., 1992) as well as two-factor interactions. Moreover, the statistical significance of these improvements can be tested in the future, though this requires maximum likelihood ratio tests with correlated data. Charnock, H. (1955) Wind stress on a water surface. Quart.J. Row. Met. Soc. 81: 639-640 Donelan, M. (1982) The dependence of aerodynamic drag coefficient on wave parameters. Proc. 1st Int. Conf. on Meteorology and Air-Sea Interactions of teh Coastal Zone. The Hague (Netherlands). AMS. 381-387 Janssen, P.A.E.M., Doyle, J., Bidlot, J., Hansen, B., Isaksen, L. and Viterbo, P. (1990) The impact of oean waves on the atmosphere. Seminars of the ECMWF. Lionello, P., Günther, H., and Janssen P.A.E.M. (1992) Assimilation of altimeter data in a global third-generation wave model. Journal of Geophysical Research 97 (C9): 453-474. Warner, J., Armstrong, B., He, R. and Zambon, J.B. (2010) Development of a Coupled Ocean-Atmosphere-Wave-Sediment Transport (COAWST) Modeling System. Ocean Modelling 35: 230-244.

Tolosana-Delgado, R.; Soret, A.; Jorba, O.; Baldasano, J. M.; Sánchez-Arcilla, A.

2012-04-01

136

Insights Into Caribbean Lithospheric Structure From S Wave Receiver Functions  

NASA Astrophysics Data System (ADS)

BOLIVAR (Broadband Ocean-Land Investigation of Venezuela and the Antilles arc Region) was aimed at investigating the interplay between the lithospheric and asthenospheric mantle of the Caribbean and the South America plates. The oblique collision of the Caribbean plate migrating eastwards has created a complicated deformation zone with strike-slip, compressional and extensional structures along the Caribbean and South America boundary. Earlier results with P receiver functions revealed strong variations in crustal thickness ranging from 15 km beneath the Caribbean Sea to 55 km beneath Venezuela. However, one of the fundamental questions not yet resolved concerns the thickness of the lithosphere in this region. Using the S wave receiver function technique, we analyzed seismograms from some 100 events at epicentral distances of 55-125 degree. The seismograms were rotated and deconvolved to isolate S-to-P conversions from the incident S wave. These were subsequently stacked after their respective conversion points and mapped into the subsurface. A strong negative phase is associated with the S-to-P conversion from the base of the lithosphere. Analysis of these data is ongoing, but we expect to see large variation in lithospheric thickness as the BOLIVAR array spans the transition from the Caribbean with OBS stations to the interior of South America (Guyana Shield).

Landes, M.; Pavlis, G. L.

2007-12-01

137

A choice of wave functions in the making of time  

NASA Astrophysics Data System (ADS)

Atomic clocks exchanging signals serve as a background against which to measure the motion of objects on or near the Earth. The background of clocks and signals requires feedback involving computation, both internal to each clock and for regulating relations between clocks. Feedback within a clock responds to a flow of measured outcomes which, by quantum theory, are unpredictable. The steering of atomic clocks in response to unpredictable occurrences of outcomes depends on a wave function, and the choice of this wave function requires an assumption underivable in any logic consistent with quantum theory—another form of unpredictability. Currently backgrounds for motion, for example used in the Global Positioning System, consist of one or another (physical) reference frame as a realization of a (mathematical) reference system that consists of a spacetime coordinate chart with a specified metric tensor field—a structure that expresses neither the unpredictability inherent in atomic clocks nor the feedback by which one deals with this unpredictability. Without requiring the assumption of a metric tensor or even a spacetime, here we introduce a novel type of reference system consisting of the records and criteria resident in real-time computers that mediate feedback, a reference system that, by expressing feedback, structures the unpredictables in a background of motion. The criteria for clock adjustment are discussed. Trade-offs involved in these criteria call for adjusting a background in response to the motion of the objects tracked.

Myers, John M.; Madjid, F. Hadi

2013-05-01

138

A wave equation migration method for receiver function imaging: 1. Theory  

Microsoft Academic Search

A wave equation-based poststack depth migration method is proposed to image the Earth's internal structure using teleseismic receiver functions. By utilizing a frequency wave number domain one-way phase screen propagator for wave field extrapolation in the migration scheme, common conversion point (CCP) stacked receiver functions are backward propagated to construct a subsurface structural image. The phase screen propagator migration method

Ling Chen; Lianxing Wen; Tianyu Zheng

2005-01-01

139

Wave functions of composite hadron states and relationship to couplings of scattering amplitudes for general partial waves  

E-print Network

In this paper we present the connection between scattering amplitudes in momentum space and wave functions in coordinate space, generalizing previous work done for s-waves to any partial wave. The relationship to the wave function of the residues of the scattering amplitudes at the pole of bound states or resonances is investigated in detail. A sum rule obtained for the couplings provides a generalization to coupled channels, any partial wave and bound or resonance states, of Weinberg's compositeness condition, which was only valid for weakly bound states in one channel and s-wave. An example, requiring only experimental data, is shown for the $\\rho$ meson indicating that it is not a composite particle of $\\pi \\pi$ but something else.

F. Aceti; E. Oset

2012-02-21

140

Impact damage detection in sandwich composite structures using Lamb waves and laser vibrometry  

NASA Astrophysics Data System (ADS)

This experimental study explores the feasibility of impact damage detection in composite sandwich structures using Lamb wave excitation and signals acquired with a laser Doppler vibrometer. Energy maps are computed from the transient velocity wave fields and used to highlight defect areas in impacted coupons of foam core and honeycomb core sandwich materials. The technique performs well for the detection of barely visible damage in this type of material, and is shown to be robust in the presence of wave reverberation. Defect extent information is not always readily retrieved from the obtained defect signatures, which depend on the wave - defect interaction mechanisms.

Lamboul, B.; Passilly, B.; Roche, J.-M.; Osmont, D.

2013-01-01

141

Colombian ocean waves and coasts modeled by special functions  

NASA Astrophysics Data System (ADS)

Modeling the ocean bottom and surface of both Atlantic and Pacific Oceans near the Colombian coast is a subject of increasing attention due to the possibility of finding oil deposits that haven't been discovered, and as a way of monitoring the ocean limits of Colombia with other countries not only covering the possibility of naval intrusion but as a chance to detect submarine devices that are used by illegal groups for different unwished purposes. In the development of this topic it would be necessary to use Standard Hydrodynamic Equations to model the mathematical shape of ocean waves that will take differential equations forms. Those differential equations will be solved using computer algebra software and methods. The mentioned solutions will involve the use of Special Functions such as Bessel Functions, Whittaker, Heun, and so on. Using the Special Functions mentioned above, the obtained results will be simulated by numerical methods obtaining the typical patterns around the Colombian coasts (both surface and bottom). Using this simulation as a non-perturbed state, any change in the patter could be taken as an external perturbation caused by a strange body or device in an specific area or region modeled, building this simulation as an ocean radar or an unusual object finder. It's worth mentioning that the use of stronger or more rigorous methods and more advanced Special Functions would generate better theoretical results, building a more accurate simulation model that would lead to a finest detection.

Duque Tisnés, Simón

2013-06-01

142

Pulse wave velocity and cognitive function in older adults.  

PubMed

Arterial stiffness may be associated with cognitive function. In this study, pulse wave velocity (PWV) was measured from the carotid to femoral (CF-PWV) and from the carotid to radial (CR-PWV) with the Complior SP System. Cognitive function was measured by 6 tests of executive function, psychomotor speed, memory, and language fluency. A total of 1433 participants were included (mean age 75 y, 43% men). Adjusting for age, sex, education, pulse rate, hemoglobin A1C, high-density lipoprotein cholesterol, hypertension, cardiovascular disease history, smoking, drinking, and depression symptoms, a CF-PWV>12 m/s was associated with a lower Mini-Mental State Examination score (coefficient: -0.31, SE: 0.11, P=0.005), fewer words recalled on Auditory Verbal Learning Test (coefficient: -1.10, SE: 0.43, P=0.01), and lower score on the composite cognition score (coefficient: -0.10, SE: 0.05, P=0.04) and marginally significantly associated with longer time to complete Trail Making Test-part B (coefficient: 6.30, SE: 3.41, P=0.06), CF-PWV was not associated with Trail Making Test-part A, Digit Symbol Substation Test, or Verbal Fluency Test. No associations were found between CR-PWV and cognitive performance measures. Higher large artery stiffness was associated with worse cognitive function, and longitudinal studies are needed to confirm these associations. PMID:23632267

Zhong, Wenjun; Cruickshanks, Karen J; Schubert, Carla R; Carlsson, Cynthia M; Chappell, Richard J; Klein, Barbara E K; Klein, Ronald; Acher, Charles W

2014-01-01

143

On the hydrogen wave function in Momentum-space, Clifford algebra and the Generating function of Gegenbauer polynomial  

E-print Network

Using the quadratic transformation and the generating function method we Perform the Fourier transformation of the wave function of coordinates of hydrogen atom and we find the analytic expression of the wave function in momentum space. We derive the matrix elements between the basis to 4-dimensions and integral representation of the generating functions of Gegenbauer polynomials. We find a relationship between a class of Clifford algebra and the generating functions of these polynomials.

Mehdi Hage-Hassan

2008-07-25

144

The effect of wave function orthogonality on the simultaneous ionization and excitation of helium  

NASA Astrophysics Data System (ADS)

Within the framework of the first-order Born approximation, the triple differential cross sections (TDCSs) for simultaneous ionization and excitation of helium are calculated. The wave function of the ejected electron is chosen to be orthogonal or non-orthogonal to the wave function of the bound electron before ionization. It is found that the orthogonality has a strong effect on the TDCS, especially when plane waves and Coulomb waves are used to describe the projectile and the ejected electron.

Liu, Li-Juan; Jia, Chang-Chun; Zhang, Li-Min; Chen, Jiao-Jiao; Chen, Zhang-Jin

2013-10-01

145

Heat Wave Hazards: An Overview of Heat Wave Impacts in Canada  

Microsoft Academic Search

Extreme heat events are natural hazards affecting Canada and many other regions of the world. This paper presents an overview of the issues involved in defining heat waves and harmful hot weather events, followed by a spatial and historical overview of heat waves across Canada, and an assessment of heat wave adaptation potential in selected cities. The Prairies, Southern Ontario,

Karen E. Smoyer-Tomic; Robyn Kuhn; Alana Hudson

2003-01-01

146

SH Wave Number Green's Function for a Layered, Elastic Half-Space. Part I: Theory and Dynamic Canyon Response by the Discrete Wave Number Boundary Element Method  

NASA Astrophysics Data System (ADS)

We present a closed-form frequency-wave number ( ? - k) Green's function for a layered, elastic half-space under SH wave propagation. It is shown that for every ( ? - k) pair, the fundamental solution exhibits two distinctive features: (1) the original layered system can be reduced to a system composed by the uppermost superficial layer over an equivalent half-space; (2) the fundamental solution can be partitioned into three different fundamental solutions, each one carrying out a different physical interpretation, i.e., an equivalent half-space, source image impact, and dispersive wave effect, respectively. Such an interpretation allows the proper use of analytical and numerical integration schemes, and ensures the correct assessment of Cauchy principal value integrals. Our method is based upon a stiffness-matrix scheme, and as a first approach we assume that observation points and the impulsive SH line-source are spatially located within the uppermost superficial layer. We use a discrete wave number boundary element strategy to test the benefits of our fundamental solution. We benchmark our results against reported solutions for an infinitely long circular canyon subjected to oblique incident SH waves within a homogeneous half-space. Our results show an almost exact agreement with previous studies. We further shed light on the impact of horizontal strata by examining the dynamic response of the circular canyon to oblique incident SH waves under different layered half-space configurations and incident angles. Our results show that modifications in the layering structure manifest by larger peak ground responses, and stronger spatial variability due to interactions of the canyon geometry with trapped Love waves in combination with impedance contrast effects.

Restrepo, Doriam; Gómez, Juan David; Jaramillo, Juan Diego

2014-09-01

147

Correlated Electron-Nuclear Dynamics with Conditional Wave Functions  

NASA Astrophysics Data System (ADS)

The molecular Schrödinger equation is rewritten in terms of nonunitary equations of motion for the nuclei (or electrons) that depend parametrically on the configuration of an ensemble of generally defined electronic (or nuclear) trajectories. This scheme is exact and does not rely on the tracing out of degrees of freedom. Hence, the use of trajectory-based statistical techniques can be exploited to circumvent the calculation of the computationally demanding Born-Oppenheimer potential-energy surfaces and nonadiabatic coupling elements. The concept of the potential-energy surface is restored by establishing a formal connection with the exact factorization of the full wave function. This connection is used to gain insight from a simplified form of the exact propagation scheme.

Albareda, Guillermo; Appel, Heiko; Franco, Ignacio; Abedi, Ali; Rubio, Angel

2014-08-01

148

Dominant partition method. [based on a wave function formalism  

NASA Technical Reports Server (NTRS)

By use of the L'Huillier, Redish, and Tandy (LRT) wave function formalism, a partially connected method, the dominant partition method (DPM) is developed for obtaining few body reductions of the many body problem in the LRT and Bencze, Redish, and Sloan (BRS) formalisms. The DPM maps the many body problem to a fewer body one by using the criterion that the truncated formalism must be such that consistency with the full Schroedinger equation is preserved. The DPM is based on a class of new forms for the irreducible cluster potential, which is introduced in the LRT formalism. Connectivity is maintained with respect to all partitions containing a given partition, which is referred to as the dominant partition. Degrees of freedom corresponding to the breakup of one or more of the clusters of the dominant partition are treated in a disconnected manner. This approach for simplifying the complicated BRS equations is appropriate for physical problems where a few body reaction mechanism prevails.

Dixon, R. M.; Redish, E. F.

1979-01-01

149

Glueball Wave Functions in U(1) Lattice Gauge Theory  

E-print Network

Standard Monte Carlo simulations have been performed for 3-dimensional U(1) lattice gauge model on improved lattices to measure the wavefunction and size of the scalar and the tensor glueballs. Our results show the radii of ~ 0.60 and ~ 1.12 in the units of string tension, or ~0.28 and ~0.52 fm, for the scalar and tensor glueballs, respectively. At finite temperature we see clear evidence of the deconfined phase, and the transition appears to be similar to that of the two-dimensional XY model as expected from universality arguments. Preliminary results show no significant changes in the glueball wave functions and the masses in the deconfined phase.

Mushtaq Loan; Yi Ying

2006-03-16

150

Multi-Determinant Wave-functions in Quantum Monte Carlo  

E-print Network

Quantum Monte Carlo (QMC) methods have received considerable attention over the last decades due to their great promise for providing a direct solution to the many-body Schrodinger equation in electronic systems. Thanks to their low scaling with number of particles, QMC methods present a compelling competitive alternative for the accurate study of large molecular systems and solid state calculations. In spite of such promise, the method has not permeated the quantum chemistry community broadly, mainly because of the fixed-node error, which can be large and whose control is difficult. In this Perspective, we present a systematic application of large scale multi-determinant expansions in QMC, and report on its impressive performance with first row dimers and the 55 molecules of the G1 test set. We demonstrate the potential of this strategy for systematically reducing the fixed-node error in the wave function and for achieving chemical accuracy in energy predictions. When compared to traditional quantum chemistr...

Morales, M A; Clark, B K; Kim, J; Scuseria, G; 10.1021/ct3003404

2013-01-01

151

Wave functions for quantum Monte Carlo calculations in solids: Orbitals from density functional theory with hybrid exchange-correlation functionals  

Microsoft Academic Search

We investigate how the fixed-node diffusion Monte Carlo energy of solids depends on single-particle orbitals used in Slater-Jastrow wave functions. We demonstrate that the dependence can be significant, in particular in the case of 3d transition-metal compounds, which we adopt as examples. We illustrate how exchange-correlation functionals with variable exact-exchange component can be exploited to reduce the fixed-node errors. On

Jindrich Kolorenc; Shuming Hu; Lubos Mitas

2010-01-01

152

Impact of a coupled ocean wave–tide–circulation system on coastal modeling  

Microsoft Academic Search

The impact of a coupled ocean wave–tide–circulation system on coastal modeling for wind waves, oceanic circulation, and water-mass simulation is investigated by coupling of two well-tested models: the third-generation wave model (WAVEWATCH-II) and the Princeton ocean model (POM). In this study, several numerical experiments in the Yellow and East China Sea (YECS) are performed for the ideal winter case and

Il-Ju Moon

2005-01-01

153

Epicenter Location of Regional Seismic Events Using Love Wave and Rayleigh Wave Ambient Seismic Noise Green's Functions  

NASA Astrophysics Data System (ADS)

We describe a novel method to locate regional seismic events based on exploiting Empirical Green's Functions (EGF) that are produced from ambient seismic noise. Elastic EGFs between pairs of seismic stations are determined by cross-correlating long time-series of ambient noise recorded at the two stations. The EGFs principally contain Rayleigh waves on the vertical-vertical cross-correlations and Love waves on the transverse-transverse cross-correlations. Earlier work (Barmin et al., "Epicentral location based on Rayleigh wave empirical Green's functions from ambient seismic noise", Geophys. J. Int., 2011) showed that group time delays observed on Rayleigh wave EGFs can be exploited to locate to within about 1 km moderate sized earthquakes using USArray Transportable Array (TA) stations. The principal advantage of the method is that the ambient noise EGFs are affected by lateral variations in structure similarly to the earthquake signals, so the location is largely unbiased by 3-D structure. However, locations based on Rayleigh waves alone may be biased by more than 1 km if the earthquake depth is unknown but lies between 2 km and 7 km. This presentation is motivated by the fact that group time delays for Love waves are much less affected by earthquake depth than Rayleigh waves; thus exploitation of Love wave EGFs may reduce location bias caused by uncertainty in event depth. The advantage of Love waves to locate seismic events, however, is mitigated by the fact that Love wave EGFs have a smaller SNR than Rayleigh waves. Here, we test the use of Love and Rayleigh wave EGFs between 5- and 15-sec period to locate seismic events based on the USArray TA in the western US. We focus on locating aftershocks of the 2008 M 6.0 Wells earthquake, mining blasts in Wyoming and Montana, and small earthquakes near Norman, OK and Dallas, TX, some of which may be triggered by hydrofracking or injection wells.

Levshin, A. L.; Barmin, M. P.; Moschetti, M. P.; Mendoza, C.; Ritzwoller, M. H.

2011-12-01

154

The 2002/2003 El Nio: Equatorial waves sequence and their impact on sea surface temperature  

E-print Network

The 2002/2003 El Niño: Equatorial waves sequence and their impact on sea surface temperature K/2003 El Nin~ o: Equatorial waves sequence and their impact on sea surface temperature, J. Geophys. Res (hereafter CP El Niño) or Modoki El Niño. CP El Niño consists in a warming of the sea surface temperature

Paris-Sud XI, Université de

155

A technique for generating shear waves in cylindrical shells under radial impact  

NASA Technical Reports Server (NTRS)

Experimental techniques are developed to study and measure the shear-wave velocity in an aluminum cylindrical shell subjected to a radial impact. The radial impact is obtained by exploding an electrical detonator inserted in plastic plugs mounted on the end of the shell. Strain gages, mounted on the outside surface of the shell at various axial locations, are used to obtain oscilloscope traces from which the shear-wave velocity can be calculated.

Blum, A.; Mortimer, R. W.; Rose, J. L.

1974-01-01

156

The stability of freak waves with regard to external impact and perturbation of initial data  

NASA Astrophysics Data System (ADS)

We investigate solutions of the equations, describing freak waves, in perspective of stability with regard to external impact and perturbation of initial data. The modeling of freak waves is based on numerical solution of equations describing a non-stationary potential flow of the ideal fluid with a free surface. We consider the two-dimensional infinitely deep flow. For waves modeling we use the equations in conformal variables. The variant of these equations is offered in [1]. Mathematical correctness of these equations was discussed in [2]. These works establish the uniqueness of solutions, offer the effective numerical solution calculation methods, prove the numerical convergence of these methods. The important aspect of numerical modeling of freak waves is the stability of solutions, describing these waves. In this work we study the questions of stability with regards to external impact and perturbation of initial data. We showed the stability of freak waves numerical model, corresponding to the external impact. We performed series of computational experiments with various freak wave initial data and random external impact. This impact means the power density on free surface. In each experiment examine two waves: the wave that was formed by external impact and without one. In all the experiments we see the stability of equation`s solutions. The random external impact practically does not change the time of freak wave formation and its form. Later our work progresses to the investigation of solution's stability under perturbations of initial data. We take the initial data that provide a freak wave and get the numerical solution. In common we take the numerical solution of equation with perturbation of initial data. The computing experiments showed that the freak waves equations solutions are stable under perturbations of initial data.So we can make a conclusion that freak waves are stable relatively external perturbation and perturbation of initial data both. 1. Zakharov V.E., Dyachenko A.I., Vasilyev O.A. New method for numerical simulation of a nonstationary potential flow of incompressible fluid with a free surface// Eur. J.~Mech. B Fluids. 2002. V. 21. P. 283-291. 2. R.V. Shamin. Dynamics of an Ideal Liquid with a Free Surface in Conformal Variables // Journal of Mathematical Sciences, Vol. 160, No. 5, 2009. P. 537-678. 3. R.V. Shamin, V.E. Zakharov, A.I. Dyachenko. How probability for freak wave formation can be found // THE EUROPEAN PHYSICAL JOURNAL - SPECIAL TOPICS Volume 185, Number 1, 113-124, DOI: 10.1140/epjst/e2010-01242-y

Smirnova, Anna; Shamin, Roman

2014-05-01

157

A microreactor functionalized with acoustic wave effects and a liquid phase catalytic reaction.  

PubMed

In a microreactor functionalized with the effects of acoustic waves such as surface acoustic waves (SAWs) and resonance oscillations (ROs) that can be generated on ferroelectric crystals by applying rf electric power, the acoustic wave-induced dynamic lattice displacement vertical to surface significantly enhanced the catalysis of Sc(OTf)(3) in aldol condensation reaction of benzaldehyde and acetophenone to chalcone, demonstrating that the functionalization provided the microreactor with reaction-controllable functions of promoting liquid phase catalytic reactions. PMID:20386801

Nishiyama, Hiroshi; Asari, Ryusuke; Inoue, Yasunobu

2010-06-21

158

Riemann {zeta} function from wave-packet dynamics  

SciTech Connect

We show that the time evolution of a thermal phase state of an anharmonic oscillator with logarithmic energy spectrum is intimately connected to the generalized Riemann {zeta} function {zeta}(s,a). Indeed, the autocorrelation function at a time t is determined by {zeta}({sigma}+i{tau},a), where {sigma} is governed by the temperature of the thermal phase state and {tau} is proportional to t. We use the JWKB method to solve the inverse spectral problem for a general logarithmic energy spectrum; that is, we determine a family of potentials giving rise to such a spectrum. For large distances, all potentials display a universal behavior; they take the shape of a logarithm. However, their form close to the origin depends on the value of the Hurwitz parameter a in {zeta}(s,a). In particular, we establish a connection between the value of the potential energy at its minimum, the Hurwitz parameter and the Maslov index of JWKB. We compare and contrast exact and approximate eigenvalues of purely logarithmic potentials. Moreover, we use a numerical method to find a potential which leads to exact logarithmic eigenvalues. We discuss possible realizations of Riemann {zeta} wave-packet dynamics using cold atoms in appropriately tailored light fields.

Mack, R.; Schleich, W. P. [Institut fuer Quantenphysik, Albert-Einstein-Allee 11, Universitaet Ulm, D-89069 Ulm (Germany); Dahl, J. P. [Institut fuer Quantenphysik, Albert-Einstein-Allee 11, Universitaet Ulm, D-89069 Ulm (Germany); Chemical Physics, Department of Chemistry, Technical University of Denmark, DTU 207, DK-2800 Kgs. Lyngby (Denmark); Moya-Cessa, H. [Institut fuer Quantenphysik, Albert-Einstein-Allee 11, Universitaet Ulm, D-89069 Ulm (Germany); Instituto Nacional de Astrofisica, Optica y Electronica, Apartado Postal 51 Y 216, 72000 Puebla (Mexico); Strunz, W. T. [Institut fuer Theoretische Physik, Technische Universitaet Dresden, D-01062 Dresden (Germany); Walser, R. [Institut fuer Quantenphysik, Albert-Einstein-Allee 11, Universitaet Ulm, D-89069 Ulm (Germany); Institut fuer Angewandte Physik, Technische Universitaet Darmstadt, D-64289 Darmstadt (Germany)

2010-09-15

159

A planetary ultra hypervelocity impact mechanics and shock wave science facility  

Microsoft Academic Search

Using the concept of intercepting orbits from a pair of Space Station serviced free flyers, a class of impact and shock wave experiments pertinent to planetary science can be performed. One proposed free flying vehicle is an impactor dispensor, and the second is the impact laboratory. How collision is achieved by utilizing essentially twice orbital velocity is demonstrated. The impactor

Thomas J. Ahrens

1987-01-01

160

Impact Energy of Functionally Graded Steels in Crack Arrester Configuration  

NASA Astrophysics Data System (ADS)

Charpy impact energy of functionally graded steels produced by electroslag remelting composed of graded ferrite and austenite layers together with bainite or martensite intermediate layer in the form of crack arrester configuration has been investigated. The results obtained in the present study indicate that the notch tip position with respect to bainite or martensite layer significantly affects the impact energy. The closer the notch tip to the tougher layer, the higher the impact energy of the composite due to increment of energy absorbed by plastic deformation zone ahead of the notch and vice versa. Empirical relationships have been determined to correlate the impact energy of functionally graded steels to the morphology of layers.

Nazari, A.; Aghazadeh Mohandesi, J.

2010-10-01

161

Landau subband wave functions and chirality manifestation in rhombohedral graphite  

NASA Astrophysics Data System (ADS)

Recently, rhombohedral graphite has been known to have a three-dimensional Dirac cone structure composed of tilted anisotropic Dirac cones, as a result of the perturbative interlayer electron hoppings. The corresponding Landau subbands have weak energy dispersions, a characteristic indicating the possible occurrence of a three-dimensional quantum Hall effect in weak magnetic fields. Since the robust zero-mode Landau subband should be topologically protected by the chirality of the Dirac fermions, here we investigate the chirality for rhombohedral graphite with regard to the Dirac cone tilt and anisotropy, for which there could exist phases mixing in the Landau subband wave functions. Both a perturbation analysis and an exact diagonalization are performed for showing the effects of the interlayer hoppings on the phases mixing. In the results the perturbations due to the interlayer hoppings are not resolvable. Rhombohedral graphite turns out to have the same chiral nature as monolayer graphene. The realizability of the three-dimensional quantum Hall effect in rhombohedral graphite is thus further supported by the manifestation of chiralities.

Ho, Ching-Hong; Chang, Cheng-Peng; Lin, Ming-Fa

2014-11-01

162

Newton force from wave function collapse: speculation and test  

E-print Network

The Diosi-Penrose model of quantum-classical boundary postulates gravity-related spontaneous wave function collapse of massive degrees of freedom. The decoherence effects of the collapses are in principle detectable if not masked by the overwhelming environmental decoherence. But the DP (or any other, like GRW, CSL) spontaneous collapses are not detectable themselves, they are merely the redundant formalism of spontaneous decoherence. To let DP collapses become testable physics, recently we extended the DP model and proposed that DP collapses are responsible for the emergence of the Newton gravitational force between massive objects. We identified the collapse rate, possibly of the order of 1/ms, with the rate of emergence of the Newton force. A simple heuristic emergence (delay) time was added to the Newton law of gravity. This non-relativistic delay is in peaceful coexistence with Einstein's relativistic theory of gravitation, at least no experimental evidence has so far surfaced against it. We derive new predictions of such a `lazy' Newton law that will enable decisive laboratory tests with available technologies. The simple equation of 'lazy' Newton law deserves theoretical and experimental studies in itself, independently of the underlying quantum foundational considerations.

Lajos Diósi

2013-12-22

163

Stress Tensor for Quantized Random Field and Wave Function Collapse  

E-print Network

The continuous spontaneous localization (CSL) theory of dynamical wave function collapse is an experimentally testable alternative to non-relativistic quantum mechanics. In it, collapse occurs because particles interact with a classical random field. However, particles gain energy from this field, i.e., particle energy is not conserved. Recently, it has been shown how to construct a theory dubbed "completely quantized collapse" (CQC) which is predictively equivalent to CSL. In CQC, a quantized random field is introduced, and CSL's classical random field becomes its eigenvalue. In CQC, energy is conserved, which allows one to understand that energy is conserved in CSL, as the particle's energy gain is compensated by the random field's energy loss. Since the random field has energy, it should have gravitational consequences. For that, one needs to know the random field's energy density. In this paper, it is shown how to construct a symmetric, conserved, energy-momentum-stress-density tensor associated with the quantized random field, even though this field obeys no dynamical equation and has no Lagrangian. Then, three examples are given involving the random field's energy density. One considers interacting particles, the second treats a "cosmological" particle creation model, the third involves the gravity of the random field.

Philip Pearle

2008-04-22

164

Quantum anti-Zeno effect without wave function reduction  

PubMed Central

We study the measurement-induced enhancement of the spontaneous decay for a two-level subsystem, where measurements are treated as couplings between the excited state and an auxiliary state rather than the von Neumann's wave function reduction. The photon radiated in a fast decay of the atom, from the auxiliary state to the excited state, triggers a quasi-measurement, as opposed to a projection measurement. Our use of the term “quasi-measurement” refers to a “coupling-based measurement”. Such frequent quasi-measurements result in an exponential decay of the survival probability of atomic initial state with a photon emission following each quasi-measurement. Our calculations show that the effective decay rate is of the same form as the one based on projection measurements. The survival probability of the atomic initial state obtained by tracing over all the photon states is equivalent to that of the atomic initial state with a photon emission following each quasi-measurement.

Ai, Qing; Xu, Dazhi; Yi, Su; Kofman, A. G.; Sun, C. P.; Nori, Franco

2013-01-01

165

Impact of Stone Removal on Renal Function: A Review  

PubMed Central

Stone removal can improve renal function by eradicating obstruction and, in certain cases, an underlying infection. Stone-removing procedures, however, may negatively impact functional integrity. Many things may impact the latter, including the procedures used, the methods of assessing function, the time when these assessments are made, the occurrence of complications, the baseline condition of the kidney, and patient-related factors. In the majority of cases, little significant functional impairment occurs. However, there are gaps in our knowledge of this subject, including the cumulative effects of multiple procedures violating the renal parenchyma and long-term functional outcomes. PMID:21935339

Wood, Kyle; Keys, Tristan; Mufarrij, Patrick; Assimos, Dean G

2011-01-01

166

Impact of Locally Suppressed Wave sources on helioseismic travel times  

E-print Network

Wave travel-time shifts in the vicinity of sunspots are typically interpreted as arising predominantly from magnetic fields, flows, and local changes in sound speed. We show here that the suppression of granulation related wave sources in a sunspot can also contribute significantly to these travel-time shifts, and in some cases, an asymmetry between in and outgoing wave travel times. The tight connection between the physical interpretation of travel times and source-distribution homogeneity is confirmed. Statistically significant travel-time shifts are recovered upon numerically simulating wave propagation in the presence of a localized decrease in source strength. We also demonstrate that these time shifts are relatively sensitive to the modal damping rates; thus we are only able to place bounds on the magnitude of this effect. We see a systematic reduction of 10-15 seconds in $p$-mode mean travel times at short distances ($\\sim 6.2$ Mm) that could be misinterpreted as arising from a shallow (thickness of 1.5 Mm) increase ($\\sim$ 4%) in the sound speed. At larger travel distances ($\\sim 24$ Mm) a 6-13 s difference between the ingoing and outgoing wave travel times is observed; this could mistakenly be interpreted as being caused by flows.

S. M. Hanasoge; S. Couvidat; S. P. Rajaguru; A. C. Birch

2007-07-10

167

Analysis of the pion wave function in the light-cone formalism  

NASA Astrophysics Data System (ADS)

We analyze several general constraints on the pionic valence-state wave function. It is found that the present model wave functions used in the light-cone formalism of perturbative quantum chromodynamics have failed to reproduce the Chernyak-Zhitnitsky (CZ) distribution amplitude which is required to fit the pionic form factor data and the reasonable valence-state structure function which does not exceed the pionic structure function data for x-->1 simultaneously. A possible model wave function which can satisfy all the general constraints has been suggested and analyzed.

Huang, Tao; Ma, Bo-Qiang; Shen, Qi-Xing

1994-02-01

168

Dynamical model for longitudinal wave functions in light-front holographic QCD  

SciTech Connect

We construct a Schrödinger-like equation for the longitudinal wave function of a meson in the valence qq{sup -bar} sector, based on the ’t Hooft model for large-N two-dimensional QCD, and combine this with the usual transverse equation from light-front holographic QCD, to obtain a model for mesons with massive quarks. The computed wave functions are compared with the wave function ansatz of Brodsky and de Téramond and used to compute decay constants and parton distribution functions. The basis functions used to solve the longitudinal equation may be useful for more general calculations of meson states in QCD. -- Highlights: •Provide relativistic quark model based on light-front holographic QCD. •Incorporate dependence on quark mass. •Consistent with the Brodsky–de Téramond quark-wave-function ansatz. •Compute meson decay constants and parton distribution functions. •Illustrate use of basis functions that could be convenient for more general numerical calculations in light-front QCD.

Chabysheva, Sophia S.; Hiller, John R., E-mail: jhiller@d.umn.edu

2013-10-15

169

Seismic anisotropy indicators in Western Tibet: Shear wave splitting and receiver function analysis  

E-print Network

Seismic anisotropy indicators in Western Tibet: Shear wave splitting and receiver function analysis mantle Tibet Seismic structure Anisotropy Using recently collected data from western Tibet we find-converted waves (receiver functions). We find that the crust of Tibet is characterized by anisotropy on the order

Levin, Vadim

170

Short-time-evolved wave functions for solving quantum many-body problems  

E-print Network

converges essentially to the exact ground state in a relatively short time. Thus a short-time evolved wave function can be an excellent approximation to the exact ground state. Such a short-time-evolved wave function can be obtained by factorizing...

Ciftja, O.; Chin, Siu A.

2003-01-01

171

Quantum Monte Carlo: Direct calculation of corrections to trial wave functions and their energies  

E-print Network

ARTICLES Quantum Monte Carlo: Direct calculation of corrections to trial wave functions, Pennsylvania 16802 Received 4 January 2000; accepted 10 March 2000 We report an improved Monte Carlo method Monte Carlo QMC method for the direct calculation of corrections to trial wave functions.1­3 We report

Anderson, James B.

172

Two-frequency mutual coherence function of electromagnetic waves in random  

E-print Network

Two-frequency mutual coherence function of electromagnetic waves in random media: a path-position mutual coherence function of an electromagnetic pulse propagating through turbulent atmosphere of arbitrary strength. The approach presented in this paper was examined in the cases of plane-wave, spherical

Morozov, Alexandre V.

173

Wave propagation in graphite/epoxy laminates due to impact  

NASA Technical Reports Server (NTRS)

The low velocity impact response of graphite-epoxy laminates is investigated theoretically and experimentally. A nine-node isoparametric finite element in conjunction with an empirical contact law was used for the theoretical investigation. Flat laminates subjected to pendulum impact were used for the experimental investigation. Theoretical results are in good agreement with strain gage experimental data. The collective results of the investigation indicate that the theoretical procedure describes the impact response of the laminate up to about 150 in/sec. impact velocity.

Tan, T. M.; Sun, C. T.

1982-01-01

174

Impact of Locally Suppressed Wave sources on helioseismic travel times  

E-print Network

Wave travel-time shifts in the vicinity of sunspots are interpreted as arising predominantly from magnetic fields, flows, and local changes in sound speed. We show here that the suppression of granulation related wave sources in a sunspot can also create travel-time shifts, and results in a strong asymmetry between in and outgoing wave travel times. The tight connection between the physical interpretation of travel times and source-distribution homogeneity is confirmed. Statistically significant travel-time shifts are recovered upon numerically simulating wave propagation in the presence of a localized decrease in source strength. We see a systematic reduction of up to 15 seconds in $p$-mode mean travel times at short distances ($\\sim 6.2$ Mm) that could be misinterpreted as arising from a shallow increase ($\\sim$ 4%) in the sound speed. A $p$-mode difference travel-time shift at larger travel distances ($\\sim 24$ Mm) of a similar order is also observed, which could mistakenly be interpreted as e.g., caused b...

Hanasoge, S M; Rajaguru, S P; Birch, A C

2007-01-01

175

Hadronic Spectra and Light-Front Wave Functions in Holographic QCD  

SciTech Connect

We show how the string amplitude {phi}(z) defined on the fifth dimension in AdS{sub 5} space can be precisely mapped to the light-front wave functions of hadrons in physical space-time. We find an exact correspondence between the holographic variable z and an impact variable {zeta}, which represents the measure of transverse separation of the constituents within the hadrons. In addition, we derive effective four dimensional Schroedinger equations for the bound states of massless quarks and gluons which exactly reproduce the anti-de Sitter conformal field theory results and give a realistic description of the light-quark meson and baryon spectrum as well as the form factors for spacelike Q{sup 2}. Only one parameter which sets the mass scale, {lambda}{sub QCD}, is introduced.

Brodsky, Stanley J. [Stanford Linear Accelerator Center, Stanford University, Stanford, California 94309 (United States); Teramond, Guy F. de [Universidad de Costa Rica, San Jose (Costa Rica)

2006-05-26

176

The impact of child sexual abuse on adult interpersonal functioning  

Microsoft Academic Search

The many studies that have examined the long-term impact of child sexual abuse (CSA) on adult functioning have primarily focused on the personal distress of survivors, largely ignoring the impact of CSA on interpersonal relationships. This article reviews empirical findings concerning the interpersonal distress of survivors as expressed in their intimate and sexual relationships. First, current conceptualizations of the relationship

Joanne L Davis; Patricia A Petretic-Jackson

2000-01-01

177

THE IMPACT OF DYNAMIC CHANNELS ON FUNCTIONAL TOPOLOGY SKELETONS  

E-print Network

THE IMPACT OF DYNAMIC CHANNELS ON FUNCTIONAL TOPOLOGY SKELETONS J. BERTHOLD AND R. LOOGEN topologies. This paper analyses the impact of dynamic channels on Eden's topology skeletons, i.e. skeletons which define process topologies such as rings, toroids, or hypercubes. We compare topology skeletons

Loogen, Rita

178

Impact of Emphysema Heterogeneity on Pulmonary Function  

PubMed Central

Objectives To investigate the association between emphysema heterogeneity in spatial distribution, pulmonary function and disease severity. Methods and Materials We ascertained a dataset of anonymized Computed Tomography (CT) examinations acquired on 565 participants in a COPD study. Subjects with chronic bronchitis (CB) and/or bronchodilator response were excluded resulting in 190 cases without COPD and 160 cases with COPD. Low attenuations areas (LAAs) (?950 Hounsfield Unit (HU)) were identified and quantified at the level of individual lobes. Emphysema heterogeneity was defined in a manner that ranged in value from ?100% to 100%. The association between emphysema heterogeneity and pulmonary function measures (e.g., FEV1% predicted, RV/TLC, and DLco% predicted) adjusted for age, sex, and smoking history (pack-years) was assessed using multiple linear regression analysis. Results The majority (128/160) of the subjects with COPD had a heterogeneity greater than zero. After adjusting for age, gender, smoking history, and extent of emphysema, heterogeneity in depicted disease in upper lobe dominant cases was positively associated with pulmonary function measures, such as FEV1 Predicted (p<.001) and FEV1/FVC (p<.001), as well as disease severity (p<0.05). We found a negative association between HI% , RV/TLC (p<0.001), and DLco% (albeit not a statistically significant one, p?=?0.06) in this group of patients. Conclusion Subjects with more homogeneous distribution of emphysema and/or lower lung dominant emphysema tend to have worse pulmonary function. PMID:25409328

Gu, Suicheng; Leader, Joseph K.; Wang, Xiaohua; Chen, Yahong; Zheng, Bin; Wu, Shandong; Gur, David; Sciurba, Frank; Pu, Jiantao

2014-01-01

179

On Dissipation Function of Ocean Waves due to Whitecapping  

SciTech Connect

The Hasselmann kinetic equation provides a statistical description of waves ensemble. Several catastrophic events are beyond statistical model. In the case of gravity waves on the surface of the deep fluid may be the most frequent and important events of such kind are whitecapping and wave breaking. It was shown earlier that such effects leads to additional dissipation in the energy contaning region around waves spectral peak, which can be simulated by means of empiric dissipative term in kinetic equation. In order to find dependence of this term with respect to nonlinearity in the system (steepness of the surface) we preformed two numerical experiments: weakly nonlinear one in the framework of 3D hydrodynamics and fully nonlinear one for 2D hydrodynamic. In spite of significantly different models and initial conditions, both these experiments yielded close results. Obtained data can be used to define analytical formula for dependence of the dissipative term of dissipation coefficient with respect to mean steepness of the surface.

Zakharov, V. E. [Department of Mathematics, University of Arizona, 617 N. Santa Rita Ave., P.O. Box 210089, Tucson, AZ 85721-0089 (United States); Waves and Solitons LLC, 918 W. Windsong Dr., Phoenix, AZ 85045 (United States); Korotkevich, A. O. [P. N. Lebedev Physical Institute RAS, 53 Leninsky Prosp., GSP-1 Moscow, 119991 (Russian Federation); Department of Mathematics and Statistics, University of New Mexico, MSC03 2150, 1 University of New Mexico, Albuquerque, NM 87131-0001 (United States); L. D. Landau Institute for Theoretical Physics RAS, 2 Kosygin Str., Moscow, 119334 (Russian Federation); Prokofiev, A. O. [L. D. Landau Institute for Theoretical Physics RAS, 2 Kosygin Str., Moscow, 119334 (Russian Federation)

2009-09-09

180

Impact of cosmic neutrinos on the gravitational-wave background  

SciTech Connect

We obtain the equation governing the evolution of the cosmological gravitational-wave background, accounting for the presence of cosmic neutrinos, up to second order in perturbation theory. In particular, we focus on the epoch during radiation dominance, after neutrino decoupling, when neutrinos yield a relevant contribution to the total energy density and behave as collisionless ultrarelativistic particles. Besides recovering the standard damping effect due to neutrinos, a new source term for gravitational waves is shown to arise from the neutrino anisotropic stress tensor. The importance of such a source term, so far completely disregarded in the literature, is related to the high velocity dispersion of neutrinos in the considered epoch; its computation requires solving the full second-order Boltzmann equation for collisionless neutrinos.

Mangilli, Anna; Bartolo, Nicola; Matarrese, Sabino; Riotto, Antonio [Institute of Space Sciences (CSIC-IEEC) Campus UAB, Torre C5 parell 2. Bellaterra (Barcelona) (Spain); Dipartimento di Fisica 'Galileo Galilei', Universita di Padova, via Marzolo 8, I-35131 Padova (Italy); Dipartimento di Fisica 'Galileo Galilei', Universita di Padova (Italy); INFN, Sezione di Padova, via Marzolo 8, I-35131 Padova (Italy); INFN, Sezione di Padova, via Marzolo 8, I-35131 Padova (Italy); CERN, Theory Division, CH-1211 Geneva 23 (Switzerland)

2008-10-15

181

Decomposition of the unsteady wave patterns for Bessho form translating-pulsating source green function  

NASA Astrophysics Data System (ADS)

In order to interpret the physical feature of Bessho form translating-pulsating source Green function, the phase function is extracted from the integral representation and stationary-phase analysis is carried out in this paper. The complex characteristics of the integral variable and segmentation of the integral intervals are discussed in m complex plane. In ? space, the interval [-?/2+ ?, -?/2+ ?-i ?] is dominant in the near-field flow, and there is a one-to-one correspondence between the real intervals in m space and the unsteady wave patterns in far field. If 4 ?>1 ( ? is the Brard number), there are three kinds of propagation wave patterns such as ring-fan wave pattern, fan wave pattern and inner V wave pattern, and if 0<4 ?<1, a ring wave pattern, an outer V and inner V wave pattern are presented in far field. The ring-fan or ring wave pattern corresponds to the interval [-?+ ?, -?/2+ ?] for integral terms about k 2, and the fan or outer V wave pattern and inner V wave pattern correspond to [-?+ ?, -?/2) and (-?/2, -?/2+ ?] respectively for terms about k 1. Numerical result shows that it is beneficial to decompose the unsteady wave patterns under the condition of ??0 by converting the integral variable ? to m. In addition, the constant-phase curve equations are derived when the source is performing only pulsating or translating.

Xiao, Wenbin; Dong, Wencai

2014-10-01

182

Random-walk approach to mapping nodal regions of N-body wave functions: Ground-state Hartree-Fock wave functions for Li-C  

NASA Astrophysics Data System (ADS)

Despite the widespread acceptance of the relevance of the nodes of one-body electronic wave functions (atomic or molecular orbitals) in determining chemical properties, relatively little is known about the corresponding nodes of many-body wave functions. As an alternative to mapping the nodal surfaces present in the ground states of many-electron systems, we have focused instead on the structural domains implied by these surfaces. In the spirit of Monte Carlo techniques, the nodal hypervolumes of a series of atomic N-body Hartree-Fock level electronic wave functions have been mapped using a random-walk simulation in 3N dimensional configuration space. The basic structural elements of the domain of atomic or molecular wave functions are identified as nodal regions (continuous volumes of the same sign) and permutational cells (identical building blocks). Our algorithm determines both the relationships among nodal regions or cells (topology) as well as the geometric properties within each structural domain. Our results indicate that ground-state Hartree-Fock wave functions generally consist of four equivalent nodal regions (two positive and two negative), each constructed from one or more permutational cells. We have developed an operational method to distinguish otherwise identical permutational cells. The limitations and most probable sources of error associated with this numerical method are discussed as are directions for future research.

Glauser, William A.; Brown, Willard R.; Lester, William A., Jr.; Bressanini, D.; Hammond, Brian L.; Koszykowski, M. L.

1992-12-01

183

The impact of tropospheric planetary wave variability on stratospheric ozone  

SciTech Connect

The goal of this project was to improve understanding of the role of the stratosphere in inducing long-term variations of the chemical composition of the troposphere. Changes in stratospheric transport occur on decadel timescales in response to changes in the structure of planetary wave patterns, forced in the troposphere. For many important tracers, such as column amounts of ozone, this variability of the transport leads to changes with signatures very similar to those induced by anthropogenic releases of chemicals into the atmosphere. During this project, a new interactive two-dimensional model of the dynamics, chemistry and radiation of the stratosphere was developed. The model was used to interpret available data of tracers. It was found that a fairly coherent picture of tracer distributions is obtained when a layer of reduced gravity wave drag is assumed for the lower stratosphere. The results suggest that the power of models to predict variability in tracer transport in the upper troposphere and lower stratosphere is limited until current theories of gravity wave breaking have been refined.

McElroy, Michael B.; Schneider, Hans R.

2002-06-25

184

Planetary wave reflection and its impact on tropospheric cold weather over Asia during January 2008  

NASA Astrophysics Data System (ADS)

Reflection of stratospheric planetary waves and its impact on tropospheric cold weather over Asia during January 2008 were investigated by applying two dimensional Eliassen-Palm (EP) flux and three-dimensional Plumb wave activity fluxes. The planetary wave propagation can clearly be seen in the longitude-height and latitude-height sections of the Plumb wave activity flux and EP flux, respectively, when the stratospheric basic state is partially reflective. Primarily, a wave packet emanating from Baffin Island/coast of Labrador propagated eastward, equatorward and was reflected over Central Eurasia and parts of China, which in turn triggered the advection of cold wind from the northern part of the boreal forest regions and Siberia to the subtropics. The wide region of Central Eurasia and China experienced extreme cold weather during the second ten days of January 2008, whereas the extraordinary persistence of the event might have occurred due to an anomalous blocking high in the Urals-Siberia region.

Nath, Debashis; Chen, Wen; Wang, Lin; Ma, Yin

2014-07-01

185

Effect of impacted surfaces of K9 glass sample and flyer on formation of failure wave  

NASA Astrophysics Data System (ADS)

In this paper, experiments were carried out to focus on the formation mechanism of failure wave. It is found in the first time that the surface of K9 glass sample, which had been immerged into 5% HCI for two hours, and the different roughness of surfaces of flyers can influence on the threshold to induce failure waves in K9 glass samples under shock wave loading. It is concluded that the formation of failure wave was related with the inherent micro-cracks on the loaded surface of glass sample, the difference in the mechanical and chemical properties between surface and inner of sample, and the stress concentration when flyer impacted on the glass sample. The job finished here will be helpful to understand the formation mechanism of failure wave, and build up its theoretical model

Zhao, Jianheng

2001-06-01

186

Examples of Heun and Mathieu functions as solutions of wave equations in curved spaces  

E-print Network

We give examples where the Heun function exists in general relativity. It turns out that while a wave equation written in the background of certain metric yields Mathieu functions as its solutions in four space-time dimensions, the trivial generalization to five dimensions results in the double confluent Heun function. We reduce this solution to the Mathieu function with some transformations.

T. Birkandan; M. Hortacsu

2006-07-25

187

Health impacts of the July 2010 heat wave in Qu?bec, Canada  

PubMed Central

Background One of the consequences of climate change is the increased frequency and intensity of heat waves which can cause serious health impacts. In Québec, July 2010 was marked by an unprecedented heat wave in recent history. The purpose of this study is to estimate certain health impacts of this heat wave. Methods The crude daily death and emergency department admission rates during the heat wave were analyzed in relation to comparison periods using 95% confidence intervals. Results During the heat wave, the crude daily rates showed a significant increase of 33% for deaths and 4% for emergency department admissions in relation to comparison periods. No displacement of mortality was observed over a 60-day horizon. Conclusions The all-cause death indicator seems to be sufficiently sensitive and specific for surveillance of exceedences of critical temperature thresholds, which makes it useful for a heat health-watch system. Many public health actions combined with the increased use of air conditioning in recent decades have contributed to a marked reduction in mortality during heat waves. However, an important residual risk remains, which needs to be more vigorously addressed by public health authorities in light of the expected increase in the frequency and severity of heat waves and the aging of the population. PMID:23336593

2013-01-01

188

Impact of rotation on stochastic excitation of gravity and gravito-inertial waves in stars  

NASA Astrophysics Data System (ADS)

Context. Gravity waves (or their signatures) are detected in stars thanks to helio- and asteroseismology, and they may play an important role in the evolution of stellar angular momentum. Moreover, a previous observational study of the CoRoT target HD 51452 demonstrated the potential strong impact of rotation on the stochastic excitation of gravito-inertial waves in stellar interiors. Aims: Our goal is to explore and unravel the action of rotation on the stochastic excitation of gravity and gravito-inertial waves in stars. Methods: The dynamics of gravito-inertial waves in stellar interiors in both radiation and in convection zones is described with a local non-traditional f-plane model. The coupling of these waves with convective turbulent flows, which leads to their stochastic excitation, is studied in this framework. Results: First, we find that in the super-inertial regime in which the wave frequency is twice as high as the rotation frequency (? > 2?), the evanescence of gravito-inertial waves in convective regions decreases with decreasing wave frequency. Next, in the sub-inertial regime (? < 2?), gravito-inertial waves become purely propagative inertial waves in convection zones. Simultaneously, turbulence in convective regions is modified by rotation. Indeed, the turbulent energy cascade towards small scales is slowed down, and in the case of rapid rotation, strongly anisotropic turbulent flows are obtained that can be understood as complex non-linear triadic interactions of propagative inertial waves. These different behaviours, due to the action of the Coriolis acceleration, strongly modify the wave coupling with turbulent flows. On one hand, turbulence weakly influenced by rotation is coupled with evanescent gravito-inertial waves. On the other hand, rapidly rotating turbulence is intrinsically and strongly coupled with sub-inertial waves. Finally, to study these mechanisms, the traditional approximation cannot be assumed because it does not properly treat the coupling between gravity and inertial waves in the sub-inertial regime. Conclusions: Our results demonstrate the action of rotation on stochastic excitation of gravity waves thanks to the Coriolis acceleration, which modifies their dynamics in rapidly rotating stars and turbulent flows. As the ratio 2?/? increases, the couplings and thus the amplitude of stochastic gravity waves are amplified.

Mathis, S.; Neiner, C.; Tran Minh, N.

2014-05-01

189

Equality Impact Assessment Summary Name of policy, function or service  

E-print Network

Equality Impact Assessment Summary Name of policy, function or service Water and Soils and Welsh&D evidence is reflected in the Water and Soils and Welsh Woodlands and Trees policy position is found Woodlands and Trees Policy Position. Purpose and aim(s) of the policy, function or service This policy

190

Equality Impact Assessment Summary Name of policy, function or service  

E-print Network

Equality Impact Assessment Summary Name of policy, function or service Education, Learning in Wales. Who will benefit mainly from this policy, function or service? . The target audiences;publication is reproduced as an appendix to the Education, Learning and Skills Benefits from Welsh Woodlands

191

Impact of lightning strikes on hospital functions.  

PubMed

Two regional hospitals were struck by lightning during a one-month period. The first hospital, which had 236 beds, suffered a direct strike to the building. This resulted in a direct spread of the power peak and temporary failure of the standard power supply. The principle problems, after restoring standard power supply, were with the fire alarm system and peripheral network connections in the digital radiology systems. No direct impact on the hardware could be found. Restarting the servers resolved all problems. The second hospital, which had 436 beds, had a lightning strike on the premises and mainly experienced problems due to induction. All affected installations had a cable connection from outside in one way or another. The power supplies never were endangered. The main problem was the failure of different communication systems (telephone, radio, intercom, fire alarm system). Also, the electronic entrance control went out. During the days after the lightening strike, multiple software problems became apparent, as well as failures of the network connections controlling the technical support systems. There are very few ways to prepare for induction problems. The use of fiber-optic networks can limit damage. To the knowledge of the authors, these are the first cases of lightning striking hospitals in medical literature. PMID:20066646

Mortelmans, Luc J M; Van Springel, Gert L J; Van Boxstael, Sam; Herrijgers, Jan; Hoflacks, Stefaan

2009-01-01

192

Modelling of tsunami-like wave run-up, breaking and impact on a vertical wall by SPH method  

NASA Astrophysics Data System (ADS)

Accurate predictions of wave run-up and run-down are important for coastal impact assessment of relatively long waves such as tsunami or storm waves. Wave run-up is, however, a complex process involving nonlinear build-up of the wave front, intensive wave breaking and strong turbulent flow, making the numerical approximation challenging. Recent advanced modelling methodologies could help to overcome these numerical challenges. For a demonstration, we study run-up of non-breaking and breaking solitary waves on a vertical wall using two methods, an enhanced smoothed particle hydrodynamics (SPH) method and the traditional non-breaking nonlinear model Tunami-N2. The Tunami-N2 model fails to capture the evolution of steep waves at the proximity of breaking that was observed in the experiments. Whereas the SPH method successfully simulates the wave propagation, breaking, impact on structure and the reform and breaking processes of wave run-down. The study also indicates that inadequate approximation of the wave breaking could lead to significant under-predictions of wave height and impact pressure on structures. The SPH model shows potential applications for accurate impact assessments of wave run-up on to coastal structures.

Dao, M. H.; Xu, H.; Chan, E. S.; Tkalich, P.

2013-12-01

193

Failure Wave in DEDF and Soda-Lime Glass during Rod Impact  

SciTech Connect

Investigations of glass by planar, and classical and symmetric Taylor impact experiments reveal that failure wave velocity vF depends on impact velocity, geometry, and type of glass. vF typically increases with impact velocity vP to between cS and cL or to {radical}2cS (shear and longitudinal wave velocity). This paper reports initial results of an investigation of failure waves associated with gold rod impact on high-density (DEDF) glass and soda-lime glass. Data are obtained by visualizing simultaneously the failure propagation in the glass with a high-speed camera and the rod penetration velocity u with flash radiography. Results for DEDF glass are reported for vP between 1.2 and 2.0 km/s, those for soda-lime glass with vP {approx_equal}1.3 km/s. It is shown that vF > u, and that in the case of DEDF glass vF/u decreases from ; 1.38 to 1.13 with increasing vp. In addition, several Taylor tests were performed. For both DEDF and soda-lime glass the vF-values, found here as well as vF- data reported in the literature, reveal that--for equal pressures--the failure wave velocities determined from Taylor tests or planar-impact tests are distinctly greater than those observed during steady-state rod penetration.

Orphal, D. L. [International Research Associates, Inc., 4450 Black Avenue, Pleasanton, CA 94566 (United States); Behner, Th.; Hohler, V. [Fraunhofer Institut fuer Kurzzeitdynamik (Ernst-Mach Institut), Eckerstr. 4, 79104 Freiburg (Germany); Anderson, C. E. Jr. [Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78228-0510 (United States); Templeton, D. W. [U. S. Army RDECOM-TACOM, AMST-TR-R, Warren, MI 48397 (United States)

2006-07-28

194

How much can BE Learnt about Pion Wave Function from the Drell-Yan Process?  

NASA Astrophysics Data System (ADS)

Contribution of the high twist Feynman diagrams to the dilepton production cross section in pion-hadron collisions is investigated. In calculations the asymptotic, Chernyak-Zhitnitsky and two other pion model wave functions P2, P3 are used. It is shown that this contribution depends on the choice of wave functions and for large dilepton transverse momentum pT and invariant mass Q in the limit bar xT-> 1 +Q2/s exceeds the leading one by an order of magnitude. Perspectives of the Drell-Yan process in the context of the pion wave function investigation are discussed.

Agaev, Shahin S.

195

The ?-meson and related meson wave functions in QCD sum rules with nonlocal condensates  

NASA Astrophysics Data System (ADS)

We apply the nonlocal condensate formalism to construct generalized sum rules (including O(?s)-radiative corrections) for ?-, ?- and ?'-meson wave functions of twist 2. Besides, we predict the lepton decay constant f?' and estimate the mass of ?'-meson. For all these mesons we obtain the first 10 moments of longitudinal wave functions, suggest the models for them and discuss their properties. We consider the peculiarities of the QCD sum rules with nonlocal condensates for transverse ?- and b1-meson wave functions. These results are compared with those found by Ball and Braun and by Chernyak and Zhitnitsky.

Bakulev, A. P.; Mikhailov, S. V.

1998-09-01

196

Non-Gaussian wave functionals in Coulomb gauge Yang-Mills theory  

SciTech Connect

A general method to treat non-Gaussian vacuum wave functionals in the Hamiltonian formulation of a quantum field theory is presented. By means of Dyson-Schwinger techniques, the static Green functions are expressed in terms of the kernels arising in the Taylor expansion of the exponent of the vacuum wave functional. These kernels are then determined by minimizing the vacuum expectation value of the Hamiltonian. The method is applied to Yang-Mills theory in Coulomb gauge, using a vacuum wave functional whose exponent contains up to quartic terms in the gauge field. An estimate of the cubic and quartic interaction kernels is given using as input the gluon and ghost propagators found with a Gaussian wave functional.

Campagnari, Davide R.; Reinhardt, Hugo [Institut fuer Theoretische Physik, Universitaet Tuebingen, Auf der Morgenstelle 14, 72076 Tuebingen (Germany)

2010-11-15

197

Impact of ozone depletion on immune function  

SciTech Connect

Depletion of stratospheric ozone is expected to lead to an increase in the amount of UV-B radiation present in sunlight. In addition to its well known ability to cause skin cancer, UV-B radiation has been shown to alter the immune system. The immune system is the body's primary defense mechanism against infectious diseases and protects against the development of certain types of cancer. Any impairment of immune function may jeopardize health by increasing susceptibility to infectious diseases, increasing the severity of infections, or delaying recovery for infections. In addition, impaired immune function can increase the incidence of certain cancers, particularly cancers of the skin. Research carried out with laboratory animals over the past 15 years has demonstrated that exposure of the skin to UV-B radiation can suppress certain types of immune responses. These include rejection of UV-induced skin cancers and melanomas, contact allergy reactions to chemicals, delayed-type hypersensitivity responses to microbial and other antigens, and phagocytosis and elimination of certain bacteria from lymphoid tissues. Recent studies with mycobacterial infection of mice demonstrated that exposure to UV-B radiation decreased the delayed hypersensitivity response to mycobacterial antigens and increased the severity of infection. In humans, UV-B radiation has also been shown to impair the contact allergy response. These studies demonstrate that UV radiation can decrease immune responses in humans and laboratory and raise the possibility that increased exposure to UV-B radiation could adversely affect human health by increasing the incidence or severity of certain infectious diseases.

Jeevan, A.; Kripke, M.L. (Univ. of Texas, Houston, TX (United States). Dept. of Immunology)

1993-06-01

198

THE DISTORTED WAVE FUNCTIONS FOR ELECTRON MOVING IN THE FIELD OF LITHIUM ATOM  

Microsoft Academic Search

The wave equation for the motion of an electron ia the static field of a ; lithium atom is solved by a numerical method for electron energy up to 340 v. ; The zero, first, and second order phases of the wave functions are plotted ; against the k values for the incident electrons. The distortions are much ; greater

T. Kou; B. Liu; T. Chee

1957-01-01

199

Structural and Functional Impact of Cancer Related Missense Somatic Mutations  

PubMed Central

A number of large scale cancer somatic genome sequencing projects are now identifying genetic alterations in cancers. Evaluation of the effects of these mutations is essential for understanding their contribution to tumorigenesis. We have used SNPs3D, a software suite originally developed for analyzing non-synonymous germ line variants, to identify single base mutations with a high impact on protein structure and function. Two machine learning methods are used, one identifying mutations that destabilize protein three dimensional structure, and the other utilizing sequence conservation, and detecting all types of effects on in vivo protein function. Incorporation of detailed structure information into the analysis allows detailed interpretation of the functional effects of mutations in specific cases. Data from a set of breast and colorectal tumors were analyzed. In known cancer genes, approaching 100% of mutations are found to impact protein function, supporting the view that these methods are appropriate for identifying driver mutations. Overall, 50% to 60% of all somatic missense mutations are predicted to have a high impact on structural stability or to more generally affect the function of the corresponding proteins. This value is similar to the fraction of all possible missense mutations that have high impact, and much higher than the corresponding one for human population SNPs, at about 30%. The majority of mutations in tumor suppressors destabilize protein structure, while mutations in oncogenes operate in more varied ways, including destabilization of the less active conformational states. The set of high impact mutations encompass the possible drivers. PMID:21763698

Shi, Zhen; Moult, John

2012-01-01

200

Impact of weightlessness on muscle function  

NASA Technical Reports Server (NTRS)

The most studied skeletal muscles which depend on gravity, "antigravity" muscles, are located in the posterior portion of the legs. Antigravity muscles are characterized generally by a different fiber type composition than those which are considered nonpostural. The gravity-dependent function of the antigravity muscles makes them particularly sensitive to weightlessness (unweighting) resulting in a substantial loss of muscle protein, with a relatively greater loss of myofibrillar (structural) proteins. Accordingly alpha-actin mRNA decreases in muscle of rats exposed to microgravity. In the legs, the soleus seems particularly responsive to the lack of weight-bearing associated with space flight. The loss of muscle protein leads to a decreased cross-sectional area of muscle fibers, particularly of the slow-twitch, oxidative (SO) ones compared to fast-twitch glycolytic (FG) or oxidative-glycolytic (FOG) fibers. In some muscles, a shift in fiber composition from SO to FOG has been reported in the adaptation to spaceflight. Changes in muscle composition with spaceflight have been associated with decreased maximal isometric tension (Po) and increased maximal shortening velocity. In terms of fuel metabolism, results varied depending on the pathway considered. Glucose uptake, in the presence of insulin, and activities of glycolytic enzymes are increased by space flight. In contrast, oxidation of fatty acids may be diminished. Oxidation of pyruvate, activity of the citric acid cycle, and ketone metabolism in muscle seem to be unaffected by microgravity.

Tischler, M. E.; Slentz, M.

1995-01-01

201

Ocean Waves Synthesis using a Spectrum-Based Turbulence Function  

Microsoft Academic Search

The representation of ocean waves is not a resolved problem in computer graphics yet. There is still no existing method that allows one to simply describe an agitated surface of any size that is visually sufficiently realistic, without using entirely physical models that are usually very complex. We present a simple method to represent and animate an ocean surface in

Sébastien Thon; Jean-michel Dischler; Djamchid Ghazanfarpour

2000-01-01

202

Data synthesis and display programs for wave distribution function analysis  

NASA Technical Reports Server (NTRS)

At the National Space Science Data Center (NSSDC) software was written to synthesize and display artificial data for use in developing the methodology of wave distribution analysis. The software comprises two separate interactive programs, one for data synthesis and the other for data display.

Storey, L. R. O.; Yeh, K. J.

1992-01-01

203

The East Atlantic - West Russia Teleconnection in the North Atlantic: Climate Impact and Relation to Rossby Wave Propagation  

NASA Technical Reports Server (NTRS)

Large-scale winter teleconnection of the East Atlantic - West Russia (EA-WR) over the Atlantic and surrounding regions is examined in order to quantify its impacts on temperature and precipitation and identify the physical mechanisms responsible for its existence. A rotated empirical orthogonal function (REOF) analysis of the upper-tropospheric monthly height field captures successfully the EA-WR pattern and its interannual variation, with the North Atlantic Oscillation as the first mode. EA-WRs climate impact extends from eastern North America to Eurasia. The positive (negative) EA-WR produces positive (negative) temperature anomalies over the eastern US, western Europe and Russia east of Caspian Sea, with negative (positive) anomalies over eastern Canada, eastern Europe including Ural Mountains and the Middle East. These anomalies are largely explained by lower-tropospheric temperature advections. Positive (negative) precipitation anomalies are found over the mid-latitude Atlantic and central Russia around 60E, where lower-level cyclonic (anticyclonic) circulation anomaly is dominant. The eastern Canada and the western Europe are characterized by negative (positive) precipitation anomalies.The EA-WR is found to be closely associated with Rossby wave propagation. Wave activity fluxes show that it is strongly tied to large-scale stationary waves. Furthermore, a stationary wave model (SWM) forced with vorticity transients in the mid-latitude Atlantic (approximately 40N) or diabatic heat source over the subtropical Atlantic near the Caribbean Sea produces well-organized EA-WR-like wave patterns, respectively. Sensitivity tests with the SWM indicate improvement in the simulation of the EA-WR when the mean state is modified to have a positive NAO component that enhances upper-level westerlies between 40-60N.

Lim, Young-Kwon

2014-01-01

204

Spontaneous generation and impact of inertia-gravity waves in a stratified, two-layer shear flow  

E-print Network

Spontaneous generation and impact of inertia-gravity waves in a stratified, two-layer shear flow P December 2003. [1] Inertia-gravity waves exist ubiquitously throughout the stratified parts inertia-gravity waves are generated as spontaneous adjustment radiation by an evolving large- scale mode

Williams, Paul

205

Impact of heat waves on mortality in Croatia.  

PubMed

The aim of this work was to determine the criteria for heat loads associated with an increase in mortality in different climatic regions of Croatia. The relationship between heat stress and mortality was analysed for the period 1983-2008. The input series is excess mortality defined as the deviations of mortality from expected values determined by means of a Gaussian filter of 183 days. The assessment of the thermal environment was performed by means of physiologically equivalent temperature (PET). The curve depicting the relationship between mortality and temperature has a U shape, with increased mortality in both the cold and warm parts of the scale but more pronounced in the warm part. The threshold temperature for increased mortality was determined using a scatter plot and fitting data by means of moving average of mortality; the latter is defined as the temperature at which excess mortality becomes significant. The values are higher in the continental part of Croatia than at the coast due to the refreshing influence of the sea during the day. The same analysis on a monthly basis shows that at the beginning of the warm season increased mortality occurs at a lower temperature compared with later on in the summer, and the difference is up to 15 °C between August and April. The increase in mortality is highest during the first 3-5 days and after that it decreases and falls below the expected value. Long-lasting heat waves present an increased risk, but in very long heat waves the increase in mortality is reduced due to mortality displacement. PMID:23995621

Zaninovi?, Ksenija; Matzarakis, Andreas

2014-08-01

206

Impact of the atmospheric climate modes on wave climate in the North Atlantic  

NASA Astrophysics Data System (ADS)

This study establishes the relationships between the mean modes of atmospheric variability in the North Atlantic and present wave climate. The modes considered, namely the North Atlantic Oscillation (NAO), the East Atlantic pattern (EA), the East Atlantic Western Russian pattern (EA/WR) and the Scandinavian pattern (SCAN), are obtained from the NOAA Climate Prediction Centre. The wave data sets used consist of buoy records and two high-resolution simulations of significant wave height (SWH), mean wave period (MWP) and mean wave direction (MWD) forced with ERA-40 (1958-2002) and ERA-INTERIM (1989-2008) wind fields. The results show the winter impact of each mode on wave parameters which are discussed regionally. The NAO and EA pattern increase winter SWH up to 1 m per unit index at the Scottish and Spanish coasts, respectively, during their positive phase; while EA pattern causes clockwise changes of winter MWD up to more than 60 degrees per unit index at the Bay of Biscay during its negative phase. EA/WR and SCAN patterns have a weaker impact.

Martínez-Asensio, Adrián; Tsimplis, Michael N.; Marcos, Marta; Feng, Xiangbo; Gomis, Damià; Jordà, Gabriel; Josey, Simon

2014-05-01

207

The Chernyak-Zhitnitsky wave function and the elastic proton form factor  

NASA Astrophysics Data System (ADS)

The Chernyak-Zhitnitsky wave function allows us to calculate the elastic proton form factor Fp1. The results of such calculations are, however, not in agreement. In order to clarify the situation we have included higher polynomials and have systematically studied the relevant parameter space. We find that (1) the sum rule wave functions do not give a precise prediction for Fp1 because the knowledge of its lowest moments does not specify the nucleon wave function sufficiently, and that (2) while the general momentum asymmetry is characteristic for all CZ wave functions the detail form depends on the manner in which the higher polynomials are suppressed. I would like to thank S.J. Brodsky for very helpful discussions, and R.C. Walker, B. Filippone, and S.E. Koonin for reading this manuscript. This work was supported in part by the National Science Foundation grants PHY85-05682 PHY86-04197.

Schäfer, Andreas

1989-02-01

208

Continuity Conditions on Schrodinger Wave Functions at Discontinuities of the Potential.  

ERIC Educational Resources Information Center

Several standard arguments which attempt to show that the wave function and its derivative must be continuous across jump discontinuities of the potential are reviewed and their defects discussed. (Author/HM)

Branson, David

1979-01-01

209

Weak Equivalence Principle and Propagation of the Wave Function in Quantum Mechanics  

E-print Network

The propagation of the wave function of a particle is characterised by a group and a phase velocity. The group velocity is associated with the particle's classical velocity, which is always smaller than the speed of light, and the phase velocity is associated with the propagation speed of the wave function phase and is treated as being unphysical, since its value is always greater than the speed of light. Here we show, using Sciama's Machian formulation of rest mass energy, that this physical interpretation, for the group and the phase velocity of the wave function, is only valid if the weak equivalence principle strictly holds for the propagating particle, except for the photon. In case this constraint is released the phase velocity of the wave function could acquire a physical meaning in quantum condensates.

Clovis Jacinto de Matos

2010-06-14

210

Composite analysis of dust impacts on African easterly waves in the Moderate Resolution Imaging Spectrometer era  

Microsoft Academic Search

This study examines the synoptic scale impacts of African dust on easterly waves in the tropical northeast Atlantic. Moderate Resolution Imaging Spectrometer aerosol optical depth (AOD), National Oceanic and Atmospheric Administration products, and National Center for Environmental Prediction reanalysis fields in the Atlantic main hurricane development region (MDR) form the basis for statistical analysis of a limited set of cases

Mark R. Jury; Myrna J. Santiago

2010-01-01

211

The Impact of Heat Islands on Mortality in Paris during the August 2003 Heat Wave  

Microsoft Academic Search

Background: Heat waves have a drastic impact on urban populations, which could increase with climate change. Objectives: We evaluated new indicators of elderly people's exposure to heat in Paris, from a public health prevention perspective, using satellite thermal images. Methods: We used a time series of 61 images from the satellites of the National Oceanic and Atmospheric Administration's (NOAA) Advanced

Karine Laaidi; Abdelkrim Zeghnoun; Bénédicte Dousset; Philippe Bretin; Stéphanie Vandentorren; Emmanuel Giraudet; Pascal Beaudeau

2012-01-01

212

Satellite remote sensing data for urban heat waves assessment and human health impacts  

NASA Astrophysics Data System (ADS)

Remote sensing is a key application in global-change science and urban climatology. Urbanization, the conversion of other types of land to uses associated with growth of populations and economy has a great impact on both micro-climate as well as macro-climate. By integrating high-resolution and medium-resolution satellite imagery with other geospatial information, have been investigated several land surface parameters including impervious surfaces and land surface temperatures for Bucharest metropolitan area in Romania. The aim of this study is to examine the changes in land use/cover pattern in a rapidly changing area of Bucharest in relation to urbanization since the 1990s till 2011 and then to investigate the impact of such changes on the intensity and spatial pattern of the UHI (Urban Heat Island) effect in the region in relation with heat waves assessment. Investigation of radiative properties, energy balance, heat fluxes and NDVI, EVI is based on satellite data provided by various sensors Landsat TM/ETM, ASTER, MODIS and IKONOS. A detailed analysis was done for summer 2003, 2007 and 2010 years heat wave events in and related impacts on human health. So called effect of "urban heat island" must be considered mostly for summer periods conditions and large European scale heat waves. As future climate trends have been predicted to increase the magnitude and negative impacts of urban heat waves in Bucharest metropolitan area, there is an urgent need to be developed adequate strategies for societal vulnerability reducing.

Zoran, M. A.; Dida, M. R.

2012-10-01

213

Impact of large-scale atmospheric refractive structures on optical wave propagation  

NASA Astrophysics Data System (ADS)

Conventional techniques used to model optical wave propagation through the Earth's atmosphere typically as- sume flow fields based on various empirical relationships. Unfortunately, these synthetic refractive index fields do not take into account the influence of transient macroscale and mesoscale (i.e. larger than turbulent microscale) atmospheric phenomena. Nevertheless, a number of atmospheric structures that are characterized by various spatial and temporal scales exist which have the potential to significantly impact refractive index fields, thereby resulting dramatic impacts on optical wave propagation characteristics. In this paper, we analyze a subset of spatio-temporal dynamics found to strongly affect optical waves propagating through these atmospheric struc- tures. Analysis of wave propagation was performed in the geometrical optics approximation using a standard ray tracing technique. Using a numerical weather prediction (NWP) approach, we simulate multiple realistic atmospheric events (e.g., island wakes, low-level jets, etc.), and estimate the associated refractivity fields prior to performing ray tracing simulations. By coupling NWP model output with ray tracing simulations, we demon- strate the ability to quantitatively assess the potential impacts of coherent atmospheric phenomena on optical ray propagation. Our results show a strong impact of spatio-temporal characteristics of the refractive index field on optical ray trajectories. Such correlations validate the effectiveness of NWP models as they offer a more comprehensive representation of atmospheric refractivity fields compared to conventional methods based on the assumption of horizontal homogeneity.

Nunalee, Christopher G.; He, Ping; Basu, Sukanta; Vorontsov, Mikhail A.; Fiorino, Steven T.

2014-10-01

214

Impact of high-frequency nonlinear internal waves on plankton dynamics in Massachusetts Bay  

E-print Network

Impact of high-frequency nonlinear internal waves on plankton dynamics in Massachusetts Bay dynamics in Massachusetts Bay (MB) during the stratified summer season. The temporal and spatial in Massachusetts Bay (MB) is based on the early study of Haury et al. (1979, 1983) (Fig. 1). They suggested

Chen, Changsheng

215

Impact of current-wave interaction on storm surge simulation: A case study for Hurricane Bob  

E-print Network

, especially following Hurricane Katrina in 2005, hurricane-induced storm surge and coastal inundation haveImpact of current-wave interaction on storm surge simulation: A case study for Hurricane Bob,2 Received 2 January 2013; revised 5 April 2013; accepted 18 April 2013; published 30 May 2013. [1] Hurricane

Chen, Changsheng

216

Blast-wave impact-mitigation capability of polyurea when used as helmet suspension-pad material  

E-print Network

work, the blast-wave impact-mitigation ability of polyurea when used as a helmet suspension-injury induced death. To assess the blast-wave impact-mitigation ability of polyurea, the temporal evolution strategies. A review of the literature carried out as part of the present work revealed that there is a clear

Grujicic, Mica

217

The dynamic dielectric at a brain functional site and an em wave approach to functional brain imaging.  

PubMed

Functional brain imaging has tremendous applications. The existing methods for functional brain imaging include functional Magnetic Resonant Imaging (fMRI), scalp electroencephalography (EEG), implanted EEG, magnetoencephalography (MEG) and Positron Emission Tomography (PET), which have been widely and successfully applied to various brain imaging studies. To develop a new method for functional brain imaging, here we show that the dielectric at a brain functional site has a dynamic nature, varying with local neuronal activation as the permittivity of the dielectric varies with the ion concentration of the extracellular fluid surrounding neurons in activation. Therefore, the neuronal activation can be sensed by a radiofrequency (RF) electromagnetic (EM) wave propagating through the site as the phase change of the EM wave varies with the permittivity. Such a dynamic nature of the dielectric at a brain functional site provides the basis for an RF EM wave approach to detecting and imaging neuronal activation at brain functional sites, leading to an RF EM wave approach to functional brain imaging. PMID:25367217

Li, X P; Xia, Q; Qu, D; Wu, T C; Yang, D G; Hao, W D; Jiang, X; Li, X M

2014-01-01

218

The Dynamic Dielectric at a Brain Functional Site and an EM Wave Approach to Functional Brain Imaging  

PubMed Central

Functional brain imaging has tremendous applications. The existing methods for functional brain imaging include functional Magnetic Resonant Imaging (fMRI), scalp electroencephalography (EEG), implanted EEG, magnetoencephalography (MEG) and Positron Emission Tomography (PET), which have been widely and successfully applied to various brain imaging studies. To develop a new method for functional brain imaging, here we show that the dielectric at a brain functional site has a dynamic nature, varying with local neuronal activation as the permittivity of the dielectric varies with the ion concentration of the extracellular fluid surrounding neurons in activation. Therefore, the neuronal activation can be sensed by a radiofrequency (RF) electromagnetic (EM) wave propagating through the site as the phase change of the EM wave varies with the permittivity. Such a dynamic nature of the dielectric at a brain functional site provides the basis for an RF EM wave approach to detecting and imaging neuronal activation at brain functional sites, leading to an RF EM wave approach to functional brain imaging. PMID:25367217

Li, X. P.; Xia, Q.; Qu, D.; Wu, T. C.; Yang, D. G.; Hao, W. D.; Jiang, X.; Li, X. M.

2014-01-01

219

Ultrasonic guided waves in cortical bone modeled as a functionally graded anisotropic tube  

E-print Network

functionally graded material with variations in material properties. A semi-analytical method based are applied to cortical bone, it can be viewed as a functionally graded material at mesoscopic scale. AmongUltrasonic guided waves in cortical bone modeled as a functionally graded anisotropic tube C. Baron

Boyer, Edmond

220

Elastic Wave Propagation in a Class of Cracked, Functionally Graded Materials by BIEM  

Microsoft Academic Search

Elastic wave propagation in cracked, functionally graded materials (FGM) with elastic parameters that are exponential functions of a single spatial co-ordinate is studied in this work. Conditions of plane strain are assumed to hold as the material is swept by time-harmonic, incident waves. The FGM has a fixed Poisson’s ratio of 0.25, while both shear modulus and density profiles vary

P. S. Dineva; T. V. Rangelov; G. D. Manolis

2007-01-01

221

Multifractal Wave Functions of a System with a Monofractal Energy Spectrum  

NASA Astrophysics Data System (ADS)

We show the appearance of multifractal wave functions on a one-dimensional quasiperiodic system that has a monofractal energy spectrum. Using the Mantica technique, we construct the model as an inverse problem from the energy spectrum of a pure Cantor set. The particle--hole symmetry and a relationship between the critical state and the information dimension are proved. This relationship is applied to the finite-size multifractal analysis of the wave functions.

Tashima, Masayuki; Tasaki, Shuichi

2011-07-01

222

Roothaan-Hartree-Fock wave functions for atoms from Cs through U  

SciTech Connect

Improved Roothaan-Hartree-Fock wave functions are reported for the atoms from Cs through U. The largest improvement in the energy, relative to the wave functions of McLean and McLean [At. Data Nucl. Data Tables 26, 197 (1981)], is 0.065 hartree for Yb. The improved energies lie no more than 0.005 hartree above numerical Hartree-Fock limits.

Koga, T. (Department of Applied Chemistry, Muroran Institute of Technology, Muroran, Hokkaido 050 (Japan)); Thakkar, A.J. (Department of Chemistry, University of New Brunswick, Fredericton, New Brunswick, E3B6E2 (Canada))

1993-12-01

223

Alpha-particle formation and decay rates from Skyrme-HFB wave functions  

E-print Network

$\\alpha$ decay is treated microscopically, where the unstable mother nucleus and residual daughter nucleus are described using HFB wave functions, obtained with the Skyrme effective interaction. From these wave functions the amplitude for forming $\\alpha$ particles in the mother nucleus is computed. Two different Skyrme parametrizations with different pairing properties are compared, and we find good agreement with experiment for relative decay rates in both cases. The absolute values of the decay rates are under-estimated.

D. E. Ward; B. G. Carlsson; S. Åberg

2014-02-10

224

Wave functions and two-electron probability distributions of the Hooke's-law atom and helium  

Microsoft Academic Search

The Hooke's-law atom (hookium) provides an exactly soluble model for a two-electron atom in which the nuclear-electron Coulombic attraction has been replaced by a harmonic one. Starting from the known exact position-space wave function for the ground state of hookium, we present the momentum-space wave function. We also look at the intracules, two-electron probability distributions, for hookium in position, momentum,

Darragh P. ONeill; Peter M. W. Gill

2003-01-01

225

sup 4 He- sup 4 He elastic scattering and variational wave functions  

SciTech Connect

We calculate differential cross sections for {sup 4}He-{sup 4}He elastic scattering at 4.32 GeV/{ital c} in the framework of Glauber multiple scattering theory using correlated variational wave functions as given by the two-nucleon Urbana {ital v}{sub 14} potential and the spin-isospin averaged Melfleit-Tjon force {ital V}. These wave functions are found to give fairly satisfactory results.

Usmani, A.A.; Ahmad, I. (Department of Physics, Aligarh Muslim University, Aligarh-202 002, Uttar Pradesh (India)); Usmani, Q.N. (Department of Physics, Jamia Millia Islamia, New Delhi-110 025 (India))

1992-01-01

226

Analysis of Real Ship Rolling Dynamics under Wave Excitement Force Composed of Sums of Cosine Functions  

SciTech Connect

The ship motion equation with a cosine wave excitement force describes the slip moments in regular waves. A new kind of wave excitement force model, with the form as sums of cosine functions was proposed to describe ship rolling in irregular waves. Ship rolling time series were obtained by solving the ship motion equation with the fourth-order-Runger-Kutta method. These rolling time series were synthetically analyzed with methods of phase-space track, power spectrum, primary component analysis, and the largest Lyapunove exponent. Simulation results show that ship rolling presents some chaotic characteristic when the wave excitement force was applied by sums of cosine functions. The result well explains the course of ship rolling's chaotic mechanism and is useful for ship hydrodynamic study.

Zhang, Y. S. [Department of Scientific Research, Dalian Naval Academy, Dalian 116018 (China); Cai, F. [Department of Navigation, Dalian Naval Academy, Dalian 116018 (China); Xu, W. M. [Department of Hydrography and Cartography, Dalian Naval Academy, Dalian 116018 (China)

2011-09-28

227

Studying Regional Wave Source Time Functions Using the Empirical Green's Function Method: Application to Central Asia  

NASA Astrophysics Data System (ADS)

Reliably estimated source time functions (STFs) from high-frequency regional waveforms, such as Lg, Pn and Pg, provide important input for seismic source studies, explosion detection and discrimination, and minimization of parameter trade-off in attenuation studies. We have searched for candidate pairs of larger and small earthquakes in and around China that share the same focal mechanism but significantly differ in magnitudes, so that the empirical Green's function (EGF) method can be applied to study the STFs of the larger events. We conducted about a million deconvolutions using waveforms from 925 earthquakes, and screened the deconvolved traces to exclude those that are from event pairs that involved different mechanisms. Only 2,700 traces passed this screening and could be further analyzed using the EGF method. We have developed a series of codes for speeding up the final EGF analysis by implementing automations and user-graphic interface procedures. The codes have been fully tested with a subset of screened data and we are currently applying them to all the screened data. We will present a large number of deconvolved STFs retrieved using various phases (Lg, Pn, Sn and Pg and coda) with information on any directivities, any possible dependence of pulse durations on the wave types, on scaling relations for the pulse durations and event sizes, and on the estimated source static stress drops.

Xie, J.; Schaff, D. P.; Chen, Y.; Schult, F.

2013-12-01

228

Wave functions and decay constants of $B$ and $D$ mesons in the relativistic potential model  

E-print Network

With the decay constants of $D$ and $D_s$ mesons measured in experiment recently, we revisit the study of the bound states of quark and antiquark in $B$ and $D$ mesons in the relativistic potential model. The relativistic bound state wave equation is solved numerically. The masses, decay constants and wave functions of $B$ and $D$ mesons are obtained. Both the masses and decay constants obtained here can be consistent with the experimental data. The wave functions can be used in the study of $B$ and $D$ meson decays.

Mao-Zhi Yang

2011-04-19

229

Calculations of inner-shell ionization by electron impact with the distorted-wave and plane-wave Born approximations  

NASA Astrophysics Data System (ADS)

A method is described for computing total cross sections for the ionization of inner shells of atoms and positive ions by impact of electrons and positrons with arbitrary energies. The method combines the relativistic plane-wave Born approximation (PWBA) with a semirelativistic version of the distorted-wave Born approximation (DWBA). Formal expressions for the longitudinal and transverse generalized oscillator strengths (GOSs) of closed shells are derived. Tables of GOSs for K shells and for L and M subshells of neutral atoms have been calculated for a discrete grid of energy losses and recoil energies. A suitable interpolation scheme allows the easy evaluation of PWBA ionization cross sections from these GOS tables. The difference between the total ionization cross sections that result from the DWBA and the PWBA (considering the longitudinal interaction only) has been calculated numerically for projectiles with kinetic energies up to 16 times the ionization energy of the active shell. In this energy range, ionization cross sections with the accuracy of a distorted-wave calculation are obtained by simply adding this difference to the cross section resulting from the conventional PWBA. For higher energies, the cross section is obtained by multiplying the PWBA cross section by an energy-dependent scaling factor that is determined by a single fitted parameter. Numerical results are shown to agree with experimental data, when these are available.

Bote, David; Salvat, Francesc

2008-04-01

230

Thermal Impact of oceanic coastal Kelvin waves along West African coasts  

NASA Astrophysics Data System (ADS)

We investigate the role of the intra-seasonal oceanic Kevin waves and their impacts on Sea Surface Temperature (SST) along the three West African coastal upwelling regions. 1/4° NEMO OGCM runs were carried out and analyzed to study the detailed of coastal wave impacts on SST. Idealized experiments support the altimetry results, and particularly the observed amplitude and velocity changes. SST impacts of up to 0.5°C/cm are visible in model runs, as well as in observations by regression of SSH on SST along coastlines. The experiments allow for a partition of lateral and vertical advection and mixing processes, and uncover their competing or constructive effects on the thermal stratification and the SST field, depending on location and mean circulation.

Wade, Malick; Lazar, Alban

2014-05-01

231

Correction Functions to Hartree-Fock Orbitals Derived from Correlated Wave Functions for He, Li, and BeLike Ions  

Microsoft Academic Search

Using energetically reliable configuration-interaction and Hartree-Fock wave functions for He(1S state)-, Li(2S and 2P states)-, and Be(1S state)-like ions, we applied the method of successive partial orthogonalizations to determine orbital correction f functions (introduced by Sinanoglu in his many-electron theory) which arise from electron-correlation effects. The addition of an f function to an appropriate Hartree-Fock orbital gives an improved orbital

G. K. Taylor; K. E. Banyard

1973-01-01

232

Correction functions to Hartree--Fock orbitals derived from correlated wave functions for He, Li, and Belike ions  

Microsoft Academic Search

Using energetically reliable configuration-interaction and Hartree-Fock ; wave functions for He(¹S state) -, Li(²S and ²P states) -, and ; Be(¹S state)-like ions, we applied the method of succasive partial ; orthogonalizations to determine orbital conection f functions (introduced by ; sinanogulu his many-electron theory) which arise from electron-correlation ; effects. The addition of an f function to an appropriate

G. K. Taylor; K. E. Banyard

1973-01-01

233

Sea state projections for the North Sea: Impact of climate change on very high waves?  

NASA Astrophysics Data System (ADS)

The research program KLIWAS of the German Federal Ministry of Transport, Building and urban Development investigates the impacts of climate change on waterways and navigation and provides options for adaptations. One aspect of the research task is to analyse climate scenarios for the sea state, eg. Sea wave height (SWH), wave direction and wave periods for the North Sea. Of particular importance for the safety on waterways is the potential change of frequence and magnitude from severe waves. The scenarios together with the wave climate of the recent years will give an approximation of projected changes of the sea state in coastal and open sea areas. Here we show the results for projected changes of medium, high and very high waves in the North Sea for the period 2000-2100 in comparison to 1961-2000, based on the wave model WAM4.5.3 The wave model is driven with wind data from two different regional atmosphere-ocean-models (DMI-HIRHAM and MPI-REMO) in the scenario A1B. The wind data are delivered in a horizontal resolution of about 20 km and a time resolution of one hour, while the wave model provides data of the calculated sea state with a horizontal grid of 5 km and the time resolution of one hour. It is seen, that in the eastern North Sea and especially in the German Bight there is a trend to a increasing of the 99th percentile of SWH, while in the western part the 99th percentile of SWH decreases in the future. These changes are mainly caused by changing wind directions in the future, while the wind speed will be mostly unaltered. Supplementary, it was carried out an extrem value analysis with the same data. Although the very high waves (eg. waves with a return period of 1-, 5-, 10-, up to 100 years) displays a similar behavior as the median or 99th percentile, there are regions in the North Sea (eg. the German Bight) with stronger changes of the higher waves. For all wave heights a strong decadal variability is detected which superimposes the calculated trends.

Möller, Jens; Groll, Nikolaus; Heinrich, Hartmut

2014-05-01

234

A test of a mechanical multi-impact shear-wave seismic source  

USGS Publications Warehouse

We modified two gasoline-engine-powered earth tampers, commonly used as compressional-(P) wave seismic energy sources for shallow reflection studies, for use as shear(S)-wave energy sources. This new configuration, termed ?Hacker? (horizontal Wacker?), is evaluated as an alternative to the manual sledgehammer typically used in conjunction with a large timber held down by the front wheels of a vehicle. The Hacker maximizes the use of existing equipment by a quick changeover of bolt-on accessories as opposed to the handling of a separate source, and is intended to improve the depth of penetration of S-wave data by stacking hundreds of impacts over a two to three minute period. Records were made with a variety of configurations involving up to two Hackers simultaneously then compared to a reference record made with a sledgehammer. Preliminary results indicate moderate success by the higher amplitude S-waves recorded with the Hacker as compared to the hammer method. False triggers generated by the backswing of the Hacker add unwanted noise and we are currently working to modify the device to eliminate this effect. Correlation noise caused by insufficient randomness of the Hacker impact sequence is also a significant noise problem that we hope to reduce by improving the coupling of the Hacker to the timber so that the operator has more control over the impact sequence.

Worley, David M.; Odum, Jack K.; Williams, Robert A.; Stephenson, William J.

2001-01-01

235

Impact of ATLAS data on parton density functions  

E-print Network

Various measurements provided by the ATLAS collaboration have significant impact on parton density functions. Inclusive production of W and Z bosons have been analysed using an NNLO QCD fit and found to constrain the strange-quark density at medium and low Bjorken-x. The inclusive jet production at different centre-of-mass energies, dijet and trijet production measured by ATLAS are used in an NLO QCD fit and show impact for the gluon and quark densities. Off-resonance Drell Yan production may be used to constrain anti-quark density at high x. The measurements have higher impact when they are used in a common fit, taking into account correlations of the systematic uncertainties and will help to constrain parton density function uncertainties.

Ellinghaus, F; The ATLAS collaboration

2014-01-01

236

RESEARCH Open Access Functional impact of Aurora A-mediated  

E-print Network

RESEARCH Open Access Functional impact of Aurora A-mediated phosphorylation of HP1 at serine 83 division, HP1 colocalizes and is phosphorylated at serine 83 (Ser83 ) in G2/M phase by Aurora A. Since Aurora A regulates both cell proliferation and mitotic aberrations, we evaluated the role of HP1

Boyer, Edmond

237

Schrödinger-Newton "collapse" of the wave function  

E-print Network

It has been suggested that the nonlinear Schr\\"odinger-Newton equation might approximate the coupling of quantum mechanics with gravitation, particularly in the context of the M{\\o}ller-Rosenfeld semiclassical theory. Numerical results for the spherically symmetric, time-dependent, single-particle case are presented, clarifying and extending previous work on the subject. It is found that, for a particle mass greater than $\\sim 1.14(\\hbar^2/(G\\sigma))^{1/3}$, a wave packet of width $\\sigma$ partially "collapses" to a groundstate solution found by Moroz, Penrose, and Tod, with excess probability dispersing away. However, for a mass less than $\\sim 1.14(\\hbar^2/(G\\sigma))^{1/3}$, the entire wave packet appears to spread like a free particle, albeit more slowly. It is argued that, on some scales (lower than the Planck scale), this theory predicts significant deviation from conventional (linear) quantum mechanics. However, owing to the difficulty of controlling quantum coherence on the one hand, and the weakness of gravity on the other, definitive experimental falsification poses a technologically formidable challenge.

J. R. van Meter

2011-05-09

238

Completeness of the Coulomb Wave Functions in Quantum Mechanics  

ERIC Educational Resources Information Center

Gives an explicit and elementary proof that the radial energy eigenfunctions for the hydrogen atom in quantum mechanics, bound and scattering states included, form a complete set. The proof uses some properties of the confluent hypergeometric functions and the Cauchy residue theorem from analytic function theory. (Author/GA)

Mukunda, N.

1978-01-01

239

Impacts and Responses to the 1995 Heat Wave: A Call to Action.  

NASA Astrophysics Data System (ADS)

The short but intense heat wave in mid-July 1995 caused 830 deaths nationally, with 525 of these deaths in Chicago. Many of the dead were elderly. and the event raised great concern over why it happened. Assessment of causes for the heat wave-related deaths in Chicago revealed many factors were at fault, including an inadequate local heat wave warning system, power failures, questionable death assessments, inadequate ambulance service and hospital facilities, the heat island, an aging population, and the inability of many persons to properly ventilate their residences due to fear of crime or a lack of resources for fans or air conditioning. Heat-related deaths appear to be on the increase in the United States. Heat-related deaths greatly exceed those caused by other life-threatening weather conditions. Analysis of the impacts and responses to this heat wave reveals a need to 1) define the heat island conditions during heat waves for all major cities is a means to improve forecasts of threatening conditions, 2) develop a nationally uniform means for classifying heat-related deaths, 3) improve warning systems that are designed around local conditions of large cities, and 4) increase research on the meteorological and climatological aspects of heat stress and heat waves.

Changnon, Stanley A.; Kunkel, Kenneth E.; Reinke, Beth C.

1996-07-01

240

Impact of IQ Discrepancy on Executive Function in High-Functioning Autism: Insight into Twice Exceptionality  

ERIC Educational Resources Information Center

We examined the impact of IQ discrepancy (IQD) within (1) and above (1+) one standard deviation on executive function in HFA using the BRIEF. We hypothesized that IQD would benefit executive function. IQD 1 is hallmarked by deficits in BRIEF indices and subscales inhibit, shift, initiate, working memory, planning and organization, and monitor…

Kalbfleisch, M. Layne; Loughan, Ashlee R.

2012-01-01

241

The 1994 heat wave in South Korea: mortality impacts and recurrence probability in a changing climate  

NASA Astrophysics Data System (ADS)

The study deals with mortality impacts of the July-August 1994 heat wave in the population of South Korea, including the megacity of Seoul (with the population exceeding 10 million for the city and 20 million for the metropolitan area), and estimates recurrence probability of the heat wave in a changing climate in terms of simulations of daily temperature series with a stochastic model. The 1994 heat wave is found exceptional with respect to both climatological characteristics and the mortality effects: significantly elevated mortality occurred in all population groups, including children up to 14 years of age, and the total death toll exceeded 3000 in the Korean population, which ranks the 1994 heat wave among the worst weather-related disasters in East Asia. The estimate represents net excess mortality as no mortality displacement effect appeared. A comparison with other documented natural disasters shows that the death toll of the heat wave was much higher than those of the most disastrous floodings and typhoons over Korean Peninsula in the 20th century. The mortality response was stronger in males than females although males are found to be less vulnerable during average heat waves. A climatological analysis reveals that the July-August 1994 heat wave might be considered an extremely rare event with a return period in the order of hundreds of years if stationarity of temperature time series is assumed. However, under a more realistic assumption of gradual warming related to climate change, recurrence probability of an event analogous to the 1994 heat wave sharply rises for near-future time horizons. If warming of 0.04°C/year is assumed over 2001-2060, the recurrence interval of a very long spell of days with temperature exceeding a high threshold (as in the 1994 heat wave) is estimated to decrease to around 40 (10) years in the 2021-2030 (2041-2050) decade. This emphasizes the need for setting up an efficient heat-watch-warning system in this area in order to reduce human mortality impacts of heat waves.

Kysely, J.; Kim, J.

2010-03-01

242

Mathieu function solutions for photoacoustic waves in sinusoidal one-dimensional structures  

NASA Astrophysics Data System (ADS)

The photoacoustic effect for a one-dimensional structure, the sound speed of which varies sinusoidally in space, is shown to be governed by an inhomogeneous Mathieu equation with the forcing term dependent on the spatial and temporal properties of the exciting optical radiation. New orthogonality relations, traveling wave Mathieu functions, and solutions to the inhomogeneous Mathieu equation are found, which are used to determine the character of photoacoustic waves in infinite and finite length phononic structures. Floquet solutions to the Mathieu equation give the positions of the band gaps, the damping of the acoustic waves within the band gaps, and the dispersion relation for photoacoustic waves. The solutions to the Mathieu equation give the photoacoustic response of the structure, show the space equivalent of subharmonic generation and acoustic confinement when waves are excited within band gaps.

Wu, Binbin; Diebold, Gerald J.

2012-07-01

243

Mathieu function solutions for photoacoustic waves in sinusoidal one-dimensional structures.  

PubMed

The photoacoustic effect for a one-dimensional structure, the sound speed of which varies sinusoidally in space, is shown to be governed by an inhomogeneous Mathieu equation with the forcing term dependent on the spatial and temporal properties of the exciting optical radiation. New orthogonality relations, traveling wave Mathieu functions, and solutions to the inhomogeneous Mathieu equation are found, which are used to determine the character of photoacoustic waves in infinite and finite length phononic structures. Floquet solutions to the Mathieu equation give the positions of the band gaps, the damping of the acoustic waves within the band gaps, and the dispersion relation for photoacoustic waves. The solutions to the Mathieu equation give the photoacoustic response of the structure, show the space equivalent of subharmonic generation and acoustic confinement when waves are excited within band gaps. PMID:23005556

Wu, Binbin; Diebold, Gerald J

2012-07-01

244

Transient difference solutions of the inhomogeneous wave equation - Simulation of the Green's function  

NASA Technical Reports Server (NTRS)

A time-dependent finite difference formulation to the inhomogeneous wave equation is derived for plane wave propagation with harmonic noise sources. The difference equation and boundary conditions are developed along with the techniques to simulate the Dirac delta function associated with a concentrated noise source. Example calculations are presented for the Green's function and distributed noise sources. For the example considered, the desired Fourier transformed acoustic pressures are determined from the transient pressures by use of a ramping function and an integration technique, both of which eliminates the nonharmonic pressure associated with the initial transient.

Baumeister, K. J.

1983-01-01

245

Direct Fragmentation of Quarkonia Including Fermi Motion Using Light-cone Wave Function  

E-print Network

We investigate the effect of Fermi motion on the direct fragmentation of the $J/\\psi$ and $\\Upsilon$ states employing a light-cone wave function. Consistent with such a wave function we set up the kinematics of a heavy quark fragmenting into a quarkonia such that the Fermi motion of the constituents split into longitudinal as well as transverse direction and thus calculate the fragmentation functions for these states. In the framework of our investigation, we estimate that the fragmentation probabilities of $J/\\psi$ and $\\Upsilon$ may increase at least up to 14 percent when including this degree of freedom.

M. A. Gomshi Nobary; B. Javadi

2005-04-13

246

Optical Transfer Function of Concave Grating Spectrometer Based on Wave Optical Method  

Microsoft Academic Search

Optical transfer functions (OTF) of two types of spectrometer --- Eagle mounting and Seya-Namioka mounting --- are calculated by the wave-optical method which defines the OTF as the autocorrelation function of the pupil. Results obtained are compared with previous results of the present authors and interpreted as effects of diffraction and aberration on the broadening of point image. The OTFs

Tsuneo Katayama; Akio Takahashi

1970-01-01

247

Kinetic Theory for Distribution Functions of Wave-Particle Interactions in Plasmas  

SciTech Connect

The evolution of a charged particle distribution function under the influence of coherent electromagnetic waves in a plasma is determined from kinetic theory. For coherent waves, the dynamical phase space of particles is an inhomogeneous mix of chaotic and regular orbits. The persistence of long time correlations between the particle motion and the phase of the waves invalidates any simplifying Markovian or statistical assumptions--the basis for usual quasilinear theories. The generalized formalism in this Letter leads to a hierarchy of evolution equations for the reduced distribution function. The evolution operators, in contrast to the quasilinear theories, are time dependent and nonsingular and include the rich phase space dynamics of particles interacting with coherent waves.

Kominis, Y.; Hizanidis, K. [School of Electrical and Computer Engineering, National Technical University of Athens, Association EURATOM-Hellenic Republic, Zographou GR-15773 (Greece); Ram, A. K. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

2010-06-11

248

Coulomb corrections in quasi-elastic scattering based on the eikonal expansion for electron wave functions  

E-print Network

An eikonal expansion is developed in order to provide systematic corrections to the eikonal approximation through order 1/k^2, where k is the wave number. The expansion is applied to wave functions for the Klein-Gordon equation and for the Dirac equation with a Coulomb potential. Convergence is rapid at energies above about 250 MeV. Analytical results for the eikonal wave functions are obtained for a simple analytical form of the Coulomb potential of a nucleus. They are used to investigate distorted-wave matrix elements for quasi-elastic electron scattering from a nucleus. Focusing factors are shown to arise from the corrections to the eikonal approximation. A precise form of the effective-momentum approximation is developed by use of a momentum shift that depends on the electron's energy loss.

J. A. Tjon; S. J. Wallace

2006-10-27

249

Impact of ATLAS Data on Parton Density Functions  

E-print Network

Various measurements provided by the ATLAS collaboration have significant impact on parton density functions. The production of W and Z bosons inclusively or in association with charm-quark have are found to constraint the strange-quark density at medium and low Bjorken-x. Multi-Jet and photon production processes show impact on the gluon density. Off-resonance Drell Yan production at large lepton pair masses may be used to constrain anti-quark density at high x. A qualitative comparison of the ATLAS measurements to predictions based on different PDFs is presented.

Newman, PR; The ATLAS collaboration

2014-01-01

250

Design of heterogeneous catalysts with artificially controllable functions using effects of acoustic wave excitation  

Microsoft Academic Search

The effects of surface acoustic waves (SAWs) and resonance oscillation (RO) of bulk acoustic waves on catalytic activity and selectivity were studied in an attempt to design a heterogeneous catalyst which has artificially controllable functions for chemical reactions. The propagation of Rayleigh SAW and shear horizontal leaky SAW through thin Pd catalyst films deposited on poled ferroelectric LiNbO3 and LiTaO3

Yasunobu Inoue

1999-01-01

251

Plasma heating by a relativistic electron beam. I - Wave kinetic equation and spectral function  

NASA Astrophysics Data System (ADS)

A new possibility for plasma heating is proposed and theoretical investigation is performed. Under a suitable experimental condition, the wave induced by the two-stream instability and Buneman/ion-acoustic wave induced by the return current can coexist and interact to yield a new contribution to plasma heating by the relativistic electron beam. The authors assume this is the case and develop the formulation necessary for the analysis of the spectral function of turbulent plasma.

Okazaki, T.; Kato, T.

1980-10-01

252

A planetary ultra hypervelocity impact mechanics and shock wave science facility  

NASA Technical Reports Server (NTRS)

Using the concept of intercepting orbits from a pair of Space Station serviced free flyers, a class of impact and shock wave experiments pertinent to planetary science can be performed. One proposed free flying vehicle is an impactor dispensor, and the second is the impact laboratory. How collision is achieved by utilizing essentially twice orbital velocity is demonstrated. The impactor dispensor contains a series of small flyer plates or other projectiles which are launched into the trajectory of the impactor laboratory at appropriate positions. The impactor laboratory is a large impact tank similar to those in terrestrial gun laboratories, except that it contains a supply of targets and instrumentation such as high speed cameras, flash X-ray apparatus, and digital recorders. Shock and isentropic pressures of up to 20 Mbar are achievable with such a system which provides 15 km/sec impact velocities for precisely oriented projectiles.

Ahrens, Thomas J.

1987-01-01

253

The impact of heat waves and cold spells on mortality rates in the Dutch population.  

PubMed Central

We conducted the study described in this paper to investigate the impact of ambient temperature on mortality in the Netherlands during 1979-1997, the impact of heat waves and cold spells on mortality in particular, and the possibility of any heat wave- or cold spell-induced forward displacement of mortality. We found a V-like relationship between mortality and temperature, with an optimum temperature value (e.g., average temperature with lowest mortality rate) of 16.5 degrees C for total mortality, cardiovascular mortality, respiratory mortality, and mortality among those [Greater and equal to] 65 year of age. For mortality due to malignant neoplasms and mortality in the youngest age group, the optimum temperatures were 15.5 degrees C and 14.5 degrees C, respectively. For temperatures above the optimum, mortality increased by 0.47, 1.86, 12.82, and 2.72% for malignant neoplasms, cardiovascular disease, respiratory diseases, and total mortality, respectively, for each degree Celsius increase above the optimum in the preceding month. For temperatures below the optimum, mortality increased 0.22, 1.69, 5.15, and 1.37%, respectively, for each degree Celsius decrease below the optimum in the preceding month. Mortality increased significantly during all of the heat waves studied, and the elderly were most effected by extreme heat. The heat waves led to increases in mortality due to all of the selected causes, especially respiratory mortality. Average total excess mortality during the heat waves studied was 12.1%, or 39.8 deaths/day. The average excess mortality during the cold spells was 12.8% or 46.6 deaths/day, which was mostly attributable to the increase in cardiovascular mortality and mortality among the elderly. The results concerning the forward displacement of deaths due to heat waves were not conclusive. We found no cold-induced forward displacement of deaths. PMID:11401757

Huynen, M M; Martens, P; Schram, D; Weijenberg, M P; Kunst, A E

2001-01-01

254

The wave-function description of the electromagnetic field  

E-print Network

For an arbitrary electromagnetic field, we define a prepotential $S$, which is a complex-valued function of spacetime. The prepotential is a modification of the two scalar potential functions introduced by E. T. Whittaker. The prepotential is Lorentz covariant under a spin half representation. For a moving charge and any observer, we obtain a complex dimensionless scalar. The prepotential is a function of this dimensionless scalar. The prepotential $S$ of an arbitrary electromagnetic field is described as an integral over the charges generating the field. The Faraday vector at each point may be derived from $S$ by a convolution of the differential operator with the alpha matrices of Dirac. Some explicit examples will be calculated. We also present the Maxwell equations for the prepotential.

Yaakov Friedman

2013-04-30

255

POINTWISE GREEN FUNCTION BOUNDS AND STABILITY OF COMBUSTION WAVES  

E-print Network

reacting compressible Navier­Stokes equations with artificial viscosity with general multi-species reaction models, including the simplified combustion model of Majda, and an artificial viscosity version, yielding a sharp L1 Lp Lp linearized stability criterion in terms of an Evans function condition, and (ii

Texier, Benjamin - Institut de Mathématiques de Jussieu, Université Paris 7

256

Influence of coastal vegetation on the 2004 tsunami wave impact in west Aceh.  

PubMed

In a tsunami event human casualties and infrastructure damage are determined predominantly by seaquake intensity and offshore properties. On land, wave energy is attenuated by gravitation (elevation) and friction (land cover). Tree belts have been promoted as "bioshields" against wave impact. However, given the lack of quantitative evidence of their performance in such extreme events, tree belts have been criticized for creating a false sense of security. This study used 180 transects perpendicular to over 100 km on the west coast of Aceh, Indonesia to analyze the influence of coastal vegetation, particularly cultivated trees, on the impact of the 2004 tsunami. Satellite imagery; land cover maps; land use characteristics; stem diameter, height, and planting density; and a literature review were used to develop a land cover roughness coefficient accounting for the resistance offered by different land uses to the wave advance. Applying a spatial generalized linear mixed model, we found that while distance to coast was the dominant determinant of impact (casualties and infrastructure damage), the existing coastal vegetation in front of settlements also significantly reduced casualties by an average of 5%. In contrast, dense vegetation behind villages endangered human lives and increased structural damage. Debris carried by the backwash may have contributed to these dissimilar effects of land cover. For sustainable and effective coastal risk management, location of settlements is essential, while the protective potential of coastal vegetation, as determined by its spatial arrangement, should be regarded as an important livelihood provider rather than just as a bioshield. PMID:22065751

Laso Bayas, Juan Carlos; Marohn, Carsten; Dercon, Gerd; Dewi, Sonya; Piepho, Hans Peter; Joshi, Laxman; van Noordwijk, Meine; Cadisch, Georg

2011-11-15

257

Multicriteria analysis to evaluate wave energy converters based on their environmental impact: an Italian case study  

NASA Astrophysics Data System (ADS)

The exploitation of renewable energy resources is fast becoming a key objective in many countries. Countries with coastlines have particularly valuable renewable energy resources in the form of tides, currents, waves and offshore wind. Due to the visual impact of siting large numbers of energy generating devices (eg. wind turbines) in terrestrial landscapes, considerable attention is now being directed towards coastal waters. Due to their environmental sensitivity, the selection of the most adequate location for these systems is a critical factor. Multi-criteria analysis allows to consider a wide variety of key characteristics (e.g. water depth, distance to shore, distance to the electric grid in land, geology, environmental impact) that may be converted into a numerical index of suitability for different WEC devices to different locations. So identifying the best alternative between an offshore or a onshore device may be specifically treated as a multicriteria problem. Special enphasisi should be given in the multicriteria analysis to the environmental impact issues. The wave energy prospective in the Italian seas is relatively low if compared to the other European countries faced to the ocean. Based on the wave climate, the Alghero site, (NW Sardinia, Italy) is one of the most interesting sites for the wave energy perspective (about 10 kW/m). Alghero site is characterized by a high level of marine biodiversity. In 2002 the area northern to Alghero harbour (Capo Caccia-Isola Piana) was established a Marine Protected Area (MPA). It could be discussed for this site how to choose between the onshore/offshore WEC alternative. An offshore device like Wave Dragon (http://www.wavedragon.net/) installed at -65m depth (width=300m and length=170 m) may approximately produce about 3.6 GWh/y with a total cost of about 9,000,000 €. On the other hand, an onshore device like SSG (http://waveenergy.no/), employed as crown wall for a vertical breakwater to enlarge the present harbour protection, and installed at -10m depth (length=300 m) may produce about 2.7 GWh/y with a total costs of about 12,000,000 €, where only the 50% of the amount are the costs of the SSG device. Obviously the environmental impact of the two solutions is quite different. Aim of this study is to provide a multicriteria decision support framework to evaluate the best WEC typology and location in the perspective of the environmental cost-benefit analysis. The general environmental aspects generated by wave power projects will be described. Colonisation patterns and biofouling will be discussed with particular reference to changes of the seabed and alterations due to new substrates. In addition, impacts for fish, fishery and marine mammals will be also considered. We suggest that wave power projects should be evaluated also on the basis of their environmental impacts in the perspective of the Strategic Environmental Assessment (SEA) analysis, as implemented by the European Commission (SEA Directive 2001/42/EC). The early incorporation of the environmental aspects involved in the evaluation of wave power projects will give the opportunity for early mitigations or design modifications, most likely making wave projects more acceptable in the long run and more suitable for the marine environment.

Azzellino, Arianna; Contestabile, Pasquale; Lanfredi, Caterina; Vicinanza, Diego

2010-05-01

258

Modified double-base propellants: Combustion wave parameters and burning rate response functions  

Microsoft Academic Search

The burning rates of modified double-base propellant at various pressures and initial temperatures were determined. The sensitivities\\u000a of the combustion wave characteristics to the pressure and initial temperature were obtained. The functions of response of\\u000a the burning rate to oscillatory pressure were calculated. Three types of response functions were identified. The errors in\\u000a determination of these functions were estimated.

A. A. Zenin; S. V. Finyakov

2009-01-01

259

Wave functions and two-electron probability distributions of the Hooke's-law atom and helium  

SciTech Connect

The Hooke's-law atom (hookium) provides an exactly soluble model for a two-electron atom in which the nuclear-electron Coulombic attraction has been replaced by a harmonic one. Starting from the known exact position-space wave function for the ground state of hookium, we present the momentum-space wave function. We also look at the intracules, two-electron probability distributions, for hookium in position, momentum, and phase space. These are compared with the Hartree-Fock results and the Coulomb holes (the difference between the exact and Hartree-Fock intracules) in position, momentum, and phase space are examined. We then compare these results with analogous results for the ground state of helium using a simple, explicitly correlated wave function.

O'Neill, Darragh P.; Gill, Peter M. W. [School of Chemistry, University of Nottingham, Nottingham NG7 2RD, (United Kingdom)

2003-08-01

260

Impact of genomic damage and ageing on stem cell function  

PubMed Central

Impairment of stem cell function contributes to the progressive deterioration of tissue maintenance and repair with ageing. Evidence is mounting that age-dependent accumulation of DNA damage in both stem cells and cells that comprise the stem cell microenvironment are partly responsible for stem cell dysfunction with ageing. Here, we review the impact of the various types of DNA damage that accumulate with ageing on stem cell functionality, as well as the development of cancer. We discuss DNA-damage-induced cell intrinsic and extrinsic alterations that influence these processes, and review recent advances in understanding systemic adjustments to DNA damage and how they affect stem cells. PMID:24576896

Behrens, Axel; van Deursen, Jan M.; Rudolph, K. Lenhard; Schumacher, Bjorn

2014-01-01

261

Impact of Shrinking Technologies on the Activation Function of Neurons  

Microsoft Academic Search

Artificial neural networks are able to solve a great variety of different applications, e.g. classification or approximation\\u000a tasks. To utilize their advantages in technical systems various hardware realizations do exist. In this work, the impact of\\u000a shrinking device sizes on the activation function of neurons is investigated with respect to area demands, power consumption\\u000a and the maximum resolution in their

Ralf Eickhoff; Tim Kaulmann; Ulrich Rückert

2007-01-01

262

Impact Of Coral Structures On Wave Directional Spreading Across A Shallow Reef Flat - Lizard Island, Northern Great Barrier Reef  

NASA Astrophysics Data System (ADS)

Coral reef hydrodynamics operate at several and overlapping spatial-temporal scales. Waves have the most important forcing function on shallow (< 5 m) reefs as they drive most ecological and biogeochemical processes by exerting direct physical stress, directly mixing water (temperature and nutrients) and transporting sediments, nutrients and plankton. Reef flats are very effective at dissipating wave energy and providing an important ecosystem service by protecting highly valued shorelines. The effectiveness of reef flats to dissipate wave energy is related to the extreme hydraulic roughness of the benthos and substrate composition. Hydraulic roughness is usually obtained empirically from frictional-dissipation calculations, as detailed field measurements of bottom roughness (e.g. chain-method or profile gauges) is a very labour and time-consuming task. In this study we measured the impact of coral structures on wave directional spreading. Field data was collected during October 2012 across a reef flat on Lizard Island, northern Great Barrier Reef. Wave surface levels were measured using an array of self-logging pressure sensors. A rapid in situ close-range photogrammetric method was used to create a high-resolution (0.5 cm) image mosaic and digital elevation model. Individual coral heads were extracted from these datasets using geo-morphometric and object-based image analysis techniques. Wave propagation was modelled using a modified version of the SWAN model which includes the measured coral structures in 2m by 1m cells across the reef. The approach followed a cylinder drag approach, neglecting skin friction and inertial components. Testing against field data included bed skin friction. Our results show, for the first time, how the variability of the reef benthos structures affects wave dissipation across a shallow reef flat. This has important implications globally for coral reefs, due to the large extent of their area occupied by reef flats, particularly, as global-scale degradation in coral reef health is causing a lowering of reef carbonate production that might lead to a decrease in reef structure and roughness.

Leon, J. X.; Baldock, T.; Callaghan, D. P.; Hoegh-guldberg, O.; Mumby, P.; Phinn, S. R.; Roelfsema, C. M.; Saunders, M. I.

2013-12-01

263

The No-Boundary Wave Function and the Duration of the Inflationary Period  

E-print Network

For the simplest minisuperspace model based on a homogeneous, isotropic metric and a minimally coupled scalar field we derive analytic expressions for the caustic which separates Euklidean and Minkowskian region and its breakdown value $\\p_*$. This value represents the prediction of the no-boundary wave function for the scalar field at the beginning of inflation. We use our results to search for inflationary models which can render the no-boundary wave function consistent with the requirement of a sufficiently long inflationary period.

A. Lukas

1994-09-07

264

Use of exponential perturbation theory in the determination of scattering wave functions  

SciTech Connect

Exponential perturbation theory (EPT) is used as the basis for generating multichannel scattering wave functions. The wave functions are constructed so that at each order of perturbation theory, the corresponding order of EPT scattering matrix is generated asymptotically. The relationship between this analysis and earlier work is examined. The usefulness of the present approach is illustrated by application to collinear single channel scattering. Perturbative solutions are generated for the test problem by separating a zeroth order interaction potential from the complete interactions. Finally, these developments are briefly reviewed and further applications discussed.

Eno, L.

1984-11-01

265

Peaks in the Hartle-Hawking Wave Function from Interfering Topologies  

NASA Astrophysics Data System (ADS)

The Hartle-Hawking ``no boundary'' wave function can receive contributions from many four-manifold topologies, and interference among these amplitudes could have important important physical implications. I describe recent results suggesting that for a universe with a negative cosmological constant, constructive interference among topologies can lead to sharp peaks in the wave function centered on homogeneous spatial geometries. While these results are unlikely to replace inflation as an explanation for the homogeneity of the Universe, they may fill in an important gap, the open problem of how to obtain an initial homogeneous patch required to start inflation.

Anderson, Mike; Carlip, Steven; Ratcliffe, John; Tschantz, Steven; Surya, Sumati

2004-05-01

266

Entanglement, scaling, and the meaning of the wave function in protective measurement  

E-print Network

We examine the entanglement and state disturbance arising in a protective measurement and argue that these inescapable effects doom the claim that protective measurement establishes the reality of the wave function. An additional challenge to this claim results from the exponential number of protective measurements required to reconstruct multi-qubit states. We suggest that the failure of protective measurement to settle the question of the meaning of the wave function is entirely expected, for protective measurement is but an application of the standard quantum formalism, and none of the hard foundational questions can ever be settled in this way.

Maximilian Schlosshauer; Tangereen V. B. Claringbold

2014-02-06

267

Impact of ocean roughness and bogus typhoons on summertime circulation in a wave-atmosphere coupled regional climate model  

Microsoft Academic Search

In order to examine the impact of ocean roughness and bogus typhoons on the east Asian summer monsoon circulation, three runs with a regional climate model (RegCM2) for 1994 summertime simulation were conducted: a control run (CTRL), a run with RegCM2 coupled to an ocean-wave model (WAVE), and a run with RegCM2 coupled to a wave model and a bogus

Dong-Kyou Lee; Young-In Ahn; Chun-Ji Kim

2004-01-01

268

Shoreline changes and high-energy wave impacts at the leeward coast of Bonaire (Netherlands Antilles)  

NASA Astrophysics Data System (ADS)

Supralittoral coarse-clast deposits along the shores of Bonaire (Netherlands Antilles) as well as increased hurricane frequency during the past decade testify to the major hazard of high-energy wave impacts in the southern Caribbean. Since deducing certain events from the subaerial coarse-clast record involves major uncertainties and historical reports are restricted to the past 500 years, we use a new set of vibracore and push core data (i) to contribute to a more reliable Holocene history of regional extreme-wave events and (ii) to evaluate their impact on shoreline evolution. Multi-proxy palaeoenvironmental analyses (XRF, XRD, grain size distribution, carbonate, LOI, microfossils) were carried out using nearshore sedimentary archives from the sheltered western (leeward) side of Bonaire and its small neighbour Klein Bonaire. In combination with 14C-AMS age estimates the stratigraphy reflects a long-term coastal evolution controlled by relative sea level rise, longshore sediment transport, and short-term morphodynamic impulses by extreme wave action, all three of which may have significantly influenced the development of polyhaline lagoons and the demise of mangrove populations. Extreme wave events may be categorized into major episodic incidents (c. 3.6 ka [?] BP; 3.2-3.0 ka BP; 2.0-1.8 ka BP; post-1.3 ka [?] BP), which may correspond to tsunamis and periodic events recurring on the order of decades to centuries, which we interpret as severe tropical cyclones. Extreme wave events seem to control to a certain extent the formation of coastal ridges on Bonaire and, thus, to cause abrupt shifts in the long-term morphodynamic and ecological boundary conditions of the circumlittoral inland bays.

Engel, M.; Brückner, H.; Messenzehl, K.; Frenzel, P.; May, S. M.; Scheffers, A.; Scheffers, S.; Wennrich, V.; Kelletat, D.

2012-10-01

269

Advanced numerical models and material characterisation techniques for composite materials subject to impact and shock wave loading  

Microsoft Academic Search

The development and validation of an advanced material model for orthotropic materials, such as fibre reinforced composites, is described. The model is specifically designed to facilitate the numerical simulation of impact and shock wave propagation through orthotropic materials and the prediction of subsequent material damage. Initial development of the model concentrated on correctly representing shock wave propagation in composite materials

R. A. Clegg; D. M. White; C. Hayhurst; W. Ridel; W. Harwick; S. Hiermaier

2003-01-01

270

Shear-Wave Velocity Structure in the Northern Basin and Range Province from the Combined Analysis of Receiver Functions and Surface Waves  

Microsoft Academic Search

A new method based on the joint inversion of receiver functions and surface-wave phase velocities results in well-determined shear-velocity structures that are consistent with the compressional-wave structure, gravity, heat flow, and elevation data in the northern Basin and Range. This new inversion method takes advantage of average-velocity information present in the surface-wave method and differential velocity information contained in the

Serdar Ozalaybey; Martha K. Savage; Anne F. Sheehan; John N. Louie; James N. Brune

1997-01-01

271

[The stimulating impact of light on brain cognition function].  

PubMed

Light regulates multiple non-visual circadian, neuroendocrine, and neurobehavioral functions, and conveys a strong stimulating signal for alert-ness and cognition. This review summarizes a series of neuroimaging studies investigating the brain mechanisms underlying the latter stimulating impact of light. Results of these studies are compatible with a scenario where light would first hit subcortical areas involved in arousal regulation before affecting cortical areas involved in the ongoing non-visual cognitive process, and then cognitive performance. Recent data demonstrated that the non-visual impact of light is most likely triggered via outputs from intrinsically photosensitive retinal ganglion cells (ipRGC) expressing the photopigment melanopsin, which are maximally sensitive to blue light. In addition, the stimulating impact of light is intimately related to wakefulness regulation as it changes with circadian phase and sleep pressure. Finally, markers of inter-individual difference have also been described: age, PERIOD3 genotype, and psychiatric status. This review emphasizes the importance of light for human brain cognitive function and for cognition in general. PMID:25311026

Vandewalle, Gilles

2014-10-01

272

Radio-wave emission due to hypervelocity impacts and its correlation with optical observations  

NASA Astrophysics Data System (ADS)

This paper describes the most interesting phenomena of radio-wave emission due to hypervelocity impacts. A projectile of polycarbonate with 1.1 g weight was accelerated by a rail gun to 3.8 km/sec, and hit two targets which are a 2 mm thick aluminum plate upstream and a 45 mm diameter aluminum column downstream, respectively. The projectile first breaks wires to give a triggering signal to a data recorder, then penetrates the aluminum plate, and finally hit the column, The emitted radio-waves propagate through the chamber window, and are received by antennas at each frequency band. The receivers in 22 GHz- and 2 GHz-bands consist of a low noise amplifier, a mixer, a local oscillator and an IF amplifier , respectively. The receiver in 1 MHz-band is a simple RF amplifier. The outputs of all receivers are fed to a data recorder which is actually a high-speed digital oscilloscope with a large amount of memory. The radio-waves were successfully recorded in 22 GHz-band with 500 MHz bandwidth, in 2 GHz-band with 300 MHz bandwidth, and in 1MHz-band. The waveforms in 22 GHz- and 2 GHz-bands coincide well each other, and are composed of two groups of sharp impulses with a separation of about 20 micro seconds. The width of an impulse is less than 2 n sec. which is the resolution limit of the data recorder. We carried out optical observations using an ultra-high speed camera simultaneously through another window of the chamber. The time interval between scenes is 2 micro sec. We can see a faint light of the projectile before the first impact to the plate, and then a brilliant gas exploding backward from the plate and forward to the column. After hitting the column target, the brilliant gas flows to the chamber wall and is reflected back to make a mixture with dark gas in the chamber. Excellent correlation between radio-wave emission and the observed optical phenomena was obtained in the experiment. It is easily conceived that the radio-waves consist of quite a wide frequency spectrum because of the spiky waveforms. The emission of the radio-waves is delayed from the optical events by several micro seconds. The optical phenomena are said to be mostly attributed to Bremstrahlung. The radio-wave phenomena are esteemed to be partially due to Bremstrahlung, but mainly due to other causes such as the heating effects of the targets or energy release from broken lattices of the targets.

Takano, T.; Maki, K.; Yamori, A.

273

Surface Wave Speed of Functionally Graded Magneto-Electro-Elastic Materials with Initial Stresses  

NASA Astrophysics Data System (ADS)

The shear surface wave at the free traction surface of half- infinite functionally graded magneto-electro-elastic material with initial stress is investigated. The material parameters are assumed to vary ex- ponentially along the thickness direction, only. The velocity equations of shear surface wave are derived on the electrically or magnetically open circuit and short circuit boundary conditions, based on the equations of motion of the graded magneto-electro-elastic material with the initial stresses and the free traction boundary conditions. The dispersive curves are obtained numerically and the influences of the initial stresses and the material gradient index on the dispersive curves are discussed. The investigation provides a basis for the development of new functionally graded magneto-electro-elastic surface wave devices.

Li, Li; Wei, P. J.

2014-09-01

274

The Impact of Structural and Functional Parameters in Glaucoma Patients on Patient-Reported Visual Functioning  

PubMed Central

Background To evaluate the impact of structural changes of the retinal nerve fiber layer (RNFL), and visual field loss, on functional impairment assessed by patient-reported visual functioning in glaucoma. Methods Patients with glaucomatous optic nerve damage were enrolled in this cross-sectional study. Peripapillary RNFL thickness was obtained with spectral-domain optical coherence tomography (SD-OCT). Function was assessed by patient-reported visual functioning using the Rasch-calibrated Glaucoma Activity Limitation 9 (GAL-9) questionnaire and standard automated perimetry. The impact of peripapillary RNFL loss on functional impairment was analyzed with correlation and linear regression analyses. Results A total of 176 eyes from 88 glaucoma patients were included. The SD-OCT assessed temporal-superior and temporal-inferior RNFL sector of the worse eye revealed significant correlation with the GAL-9 scores (r=-0.298, p=0.011 and r=-0.251, p=0.033, respectively). In mutivariate regression analysis, the best predictors for patient-reported visual functioning were visual acuity of the better eye and mean defect of the worse eye (R2=0.334), while structural parameters could not enhance the prediction of GAL-9 scores. Conclusions Self-reported visual functioning of patients with glaucoma is better predicted by visual performance data than structural parameters. However, some structural changes of the worse eye are significantly correlated with patient-reported visual functioning. PMID:24312500

Hirneiss, Christoph; Reznicek, Lukas; Vogel, Michaela; Pesudovs, Konrad

2013-01-01

275

Multi-functional Nanowire Evanescent Wave Optical Sensors  

SciTech Connect

Controlling the flow of photons through a fluidic media withsubwavelength optics is a major step towards the development of on-chipphotonic sensors. Central to this idea will be designing amulti-functional nanomaterial that can efficiently trap, route anddeliver light to various sensing channels, filters and detectors on aphotonic chip. Semiconductor nanowire waveguides offer an exceptionalsolution to the confinement of optical energy in solution and can bedirectly integrated into microfluidic devices. Here we demonstrate anovel optical sensing platform that utilizes the evanescent field of atin dioxide single crystalline waveguide to perform a wide array ofspectroscopic analyses including absorption, fluorescence and surfaceenhanced Raman on sub-picoliter probe volumes. Since the same waveguidecavity can transmit both broadband and monochromatic light it allowsmultiple modes of detection to be carried out on the same analyte. Tomove beyond less chemical specific optical techniques such as absorptionand fluorescence we exploit the amplified electric field around silvernanocubes to enhance the vibronic signatures of molecules present in theevanescent field. With excellent chemical resilience to strong acidicconditions, the waveguides can be completely cleaned from the attachedmetal nanoparticles making the devices fully reusable. These results openup the possibility of engineering self-contained, multiplexed photonicsensors that detect and identify chemical species in complex biologicaland environmental systems.

Sirbuly, Donald J.; Tao, Andrea; Law, Matt; Fan, Rong; Yang,Peidong

2006-10-18

276

Electromagnetic wave emitting products and "Kikoh" potentiate human leukocyte functions.  

PubMed

Tourmaline (electric stone, a type of granite stone), common granite stone, ceramic disks, hot spring water and human palmar energy (called "Kikoh" in Japan and China), all which emit electromagnetic radiation in the far infrared region (wavelength 4-14 microns). These materials were thus examined for effects on human leukocyte activity and on lipid peroxidation of unsaturated fatty acids. It was revealed that these materials significantly increased intracellular calcium ion concentration, phagocytosis, and generation of reactive oxygen species in neutrophils, and the blastogenetic response of lymphocytes to mitogens. Chemotactic activity by neutrophils was also enhanced by exposure to tourmaline and the palm of "Kikohshi" i.e., a person who heals professionally by the laying on of hands. Despite the increase in reactive oxygen species generated by neutrophils, lipid peroxidation from unsaturated fatty acid was markedly inhibited by these four materials. The results suggest that materials emitting electromagnetic radiation in the far infrared range, which are widely used in Japan for cosmetic, therapeutic, and preservative purposes, appear capable of potentiating leukocyte functions without promoting oxidative injury. PMID:8406976

Niwa, Y; Iizawa, O; Ishimoto, K; Jiang, X; Kanoh, T

1993-09-01

277

The impact of ankylosing spondylitis on female sexual functions.  

PubMed

The aim of this study was to explore the impact of ankylosing spondylitis (AS) and the disease-related variables, psychological status and the quality of life on the female patients' sexual function measured according to the Female Sexual Function Index (FSFI). Thirty-seven sexually active female AS patients and 33 healthy controls were enroled in this study. Their demographic data were evaluated and the generalised pain in patients with AS was assessed according to the visual analogue scale (0-100?mm). Laboratory tests were conducted in order to measure the C-reactive protein (CRP) and erythrocyte sedimentation rates (ESR) of the patients. In comparison to the healthy control group, patients with AS had significantly lower scores in each of the five domains of the FSFI except for the pain domain (P<0.05). The disease activity, functional status, quality of life, radiological score and CRP levels were negatively correlated with the FSFI (P<0.05). No significant correlation was observed with the disease duration, smoking status, depression, anxiety, pain and ESR when the total scores and the scores from the domains of the FSFI were compared. The sexual function is impaired in female patients with AS. This impairment in the sexual function is especially related to the functional status and disease activity among the clinical and laboratory parameters. PMID:23303332

Sariyildiz, M A; Batmaz, I; Inanir, A; Dilek, B; Bozkurt, M; Bez, Y; Karakoç, M; Cevik, R

2013-05-01

278

Estimation of the real aperture radar modulation transfer function directly from synthetic aperture radar ocean wave image spectra without a priori knowledge of the ocean wave height spectrum  

Microsoft Academic Search

The phase and amplitude of the real aperture radar (RAR) modulation transfer function (MTF) are, applying both simulated and real synthetic aperture radar (SAR) image spectra, shown to strongly influence the SAR ocean wave imaging of range- (or near-range) traveling wave systems. Conventionally, in situ measurement of the sea state has been used in connection with SAR estimation of the

S. Jacobsen; K. A. Høgda

1994-01-01

279

Non-dipolar Wilson links for transverse-momentum-dependent wave functions  

E-print Network

We propose definitions of transverse-momentum-dependent wave functions with simpler soft subtractions for $k_T$ factorization of hard exclusive processes. The un-subtracted wave functions involve two pieces of non-light-like Wilson links, which are oriented in different directions, so that the rapidity singularity appearing in usual $k_T$ factorization is regularized, and the pinched singularity from Wilson-link self-energy corrections is alleviated to a logarithmic one. Then only a single soft function is required to remove the logarithmic soft divergence, and even no soft function is needed, when the two pieces of Wilson links are orthogonal to each other. We show at one-loop level that the simpler definitions with the non-dipolar Wilson links exhibit the same infrared behavior as the one proposed by Collins recently, and satisfy the similar evolution equation in Wilson-link rapidity.

Hsiang-nan Li; Yu-Ming Wang

2014-10-27

280

The incomplete plasma dispersion function: Properties and application to waves in bounded plasmas  

SciTech Connect

The incomplete plasma dispersion function is a generalization of the plasma dispersion function in which the defining integral spans a semi-infinite, rather than infinite, domain. It is useful for describing the linear dielectric response and wave dispersion in non-Maxwellian plasmas when the distribution functions can be approximated as Maxwellian over finite, or semi-infinite, intervals in velocity phase-space. A ubiquitous example is the depleted Maxwellian electron distribution found near boundary sheaths or double layers, where the passing interval can be modeled as Maxwellian with a lower temperature than the trapped interval. The depleted Maxwellian is used as an example to demonstrate the utility of using the incomplete plasma dispersion function for calculating modifications to wave dispersion relations.

Baalrud, S. D. [Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa 52242 (United States)

2013-01-15

281

Econophysics: Master curve for price-impact function  

NASA Astrophysics Data System (ADS)

The price reaction to a single transaction depends on transaction volume, the identity of the stock, and possibly many other factors. Here we show that, by taking into account the differences in liquidity for stocks of different size classes of market capitalization, we can rescale both the average price shift and the transaction volume to obtain a uniform price-impact curve for all size classes of firm for four different years (1995-98). This single-curve collapse of the price-impact function suggests that fluctuations from the supply-and-demand equilibrium for many financial assets, differing in economic sectors of activity and market capitalization, are governed by the same statistical rule.

Lillo, Fabrizio; Farmer, J. Doyne; Mantegna, Rosario N.

2003-01-01

282

A wave-function Monte Carlo method for simulating conditional master equations  

E-print Network

Wave-function Monte Carlo methods are an important tool for simulating quantum systems, but the standard method cannot be used to simulate decoherence in continuously measured systems. Here we present a new Monte Carlo method for such systems. This was used to perform the simulations of a continuously measured nano-resonator in [Phys. Rev. Lett. 102, 057208 (2009)].

Kurt Jacobs

2009-06-25

283

Schrödinger Wave Function for a Free Falling Particle in the Schwarzschild Black Hole  

E-print Network

We use the time-dependent invariant method in a geometric approach (Jacobi fields) to quantize the motion of a free falling point particle in the Schwarzschild black hole. Assuming that the particle comes from infinity, we obtain the relativistic Schr\\"{o}dinger wave function for this system.

A. C. V. V. de Siqueira; I. A. Pedrosa; E. R. Bezerra de Mello

1997-09-12

284

On-Chip Electric Waves: An Analog Circuit Approach to Physical Uncloneable Functions  

E-print Network

uncloneable functions (PUFs). We argue that analog circuits offer higher security than existing digital PUFs dynamics that depends upon the interconnection strengths to their neighbors. They can be designed to evolve that directly emulates nonlinear wave propagation phenomena in a random media. It effectively translates

285

COLLECTIVE MOTION IN THE NUCLEAR SHELL MODEL. II. THE INTRODUCTION OF INTRINSIC WAVE-FUNCTIONS  

Microsoft Academic Search

The wave functions for a number of particles in a degenerate oscillator ; level are expressed as integrals of the Hill-Wheeler type over intrinsic states. ; The rotational band structure which appeared in the classification is now ; understood, since all states of a band are shown to involve the same intrinsic ; staff in the integral. It is possible

J. P. Elliott

1958-01-01

286

BLOCH model wave functions and pseudopotentials for all fractional Chern insulators.  

PubMed

We introduce a Bloch-like basis in a C-component lowest Landau level fractional quantum Hall (FQH) effect, which entangles the real and internal degrees of freedom and preserves an N(x)×N(y) full lattice translational symmetry. We implement the Haldane pseudopotential Hamiltonians in this new basis. Their ground states are the model FQH wave functions, and our Bloch basis allows for a mutatis mutandis transcription of these model wave functions to the fractional Chern insulator of arbitrary Chern number C, obtaining wave functions different from all previous proposals. For C>1, our wave functions are related to color-dependent magnetic-flux inserted versions of Halperin and non-Abelian color-singlet states. We then provide large-size numerical results for both the C = 1 and C = 3 cases. This new approach leads to improved overlaps compared to previous proposals. We also discuss the adiabatic continuation from the fractional Chern insulator to the FQH in our Bloch basis, both from the energy and the entanglement spectrum perspectives. PMID:23521277

Wu, Yang-Le; Regnault, N; Bernevig, B Andrei

2013-03-01

287

Analytic calculation of energies and wave functions of the quartic and pure quartic oscillators  

Microsoft Academic Search

Ground state energies and wave functions of quartic and pure quartic oscillators are calculated by first casting the Schro¨dinger equation into a nonlinear Riccati form and then solving that nonlinear equation analytically in the first iteration of the quasilinearization method (QLM). In the QLM the nonlinear differential equation is solved by approximating the nonlinear terms by a sequence of linear

E. Z. Liverts; V. B. Mandelzweig; F. Tabakin

2006-01-01

288

On the Distribution of the Wave Function for Systems in Thermal Equilibrium  

E-print Network

quantum systems, where distributions on H are often used. Key words: canonical ensemble in quantum theory For a quantum system, a density matrix #26; that is not pure can arise, via averaging, from a distribution #22On the Distribution of the Wave Function for Systems in Thermal Equilibrium Sheldon Goldstein #3

Goldstein, Sheldon

289

Exact ground state of strongly correlated electron systems from symmetry-entangled wave-functions  

NASA Astrophysics Data System (ADS)

The four-site Hubbard model is considered from the exact diagonalisation and variational method points of view. It is shown that the exact ground-state can be recovered by a symmetry projected Slater determinant, irrespective of the interaction strength. This is in contrast to the Gutzwiller wave-function, which is calculated as well.

Leprévost, Alexandre; Juillet, Olivier; Frésard, Raymond

2014-10-01

290

Ultrasonics/Baron Propagation of elastic waves in an anisotropic functionally graded hollow cylinder in  

E-print Network

Ultrasonics/Baron Propagation of elastic waves in an anisotropic functionally graded hollow on the Ocean, the atmosphere or the Earth, but the teeth, the bone, the shells and the insects wings are also is an anisotropic hollow cylinder with elastic properties (stiffness coefficients cij and mass density

Jirsa, Viktor

291

Foldy-Wouthuysen wave functions and conditions of transformation between Dirac and Foldy-Wouthuysen representations  

SciTech Connect

The block diagonalization of the Hamiltonian is not sufficient for the transformation to the Foldy-Wouthuysen (FW) representation. The conditions enabling the transition from the Dirac representation to the FW one are formulated and proven. The connection between wave functions in the two representations is derived. The results obtained allow calculating expectation values of operators corresponding to main classical quantities.

Neznamov, V. P. [Russian Federal Nuclear Center-The All-Russian Research Institute of Experimental Physics, Sarov 607190 (Russian Federation); Silenko, A. J. [Research Institute of Nuclear Problems, Belarusian State University, Minsk 220030 (Belarus)

2009-12-15

292

Surface Acoustic Waves in an Infinite Plate of Functionally Graded Materials  

E-print Network

, and Jianke Du Piezoelectric Device Laboratory, Mechanics and Materials Science Research Center, School the thickness direction uniformly, we obtained the frequency equation by satisfying boundary conditions, such benefits of functionally graded materials (FGMs) in surface acoustic waves have great potential in the new

Wang, Ji

293

Alternative Form of the Hydrogenic Wave Functions for an Extended, Uniformly Charged Nucleus.  

ERIC Educational Resources Information Center

Presented are forms of harmonic oscillator attraction and Coulomb wave functions which can be explicitly constructed and which lead to numerical results for the energy eigenvalues and eigenfunctions of the atomic system. The Schrodinger equation and its solution and specific cases of muonic atoms illustrating numerical calculations are included.…

Ley-Koo, E.; And Others

1980-01-01

294

Is it possible to construct the Proton Structure Function by Lorentz-boosting the Static Quark-model Wave Function?  

E-print Network

The energy-momentum relations for massive and massless particles are E = p^2/2m and E = pc respectively. According to Einstein, these two different expressions come from the same formula E = \\sqrt{(cp)^2 + m^2 c^4}. Quarks and partons are believed to be the same particles, but they have quite different properties. Are they two different manifestations of the same covariant entity as in the case of Einstein's energy-momentum relation? The answer to this question is YES. It is possible to construct harmonic oscillator wave functions which can be Lorentz-boosted. They describe quarks bound together inside hadrons. When they are boosted to an infinite-momentum frame, these wave functions exhibit all the peculiar properties of Feynman's parton picture. This formalism leads to a parton distribution corresponding to the valence quarks, with a good agreement with the experimentally observed distribution.

Y. S. Kim; Marilyn E. Noz

2004-07-12

295

Dissipation of Magnetohydrodynamic Waves on Energetic Particles: Impact on Interstellar Turbulence and Cosmic Ray Transport  

SciTech Connect

The physical processes involved in diffusion of Galactic cosmic rays in the interstellar medium are addressed. We study the possibility that the nonlinear MHD cascade sets the power-law spectrum of turbulence which scatters charged energetic particles. We find that the dissipation of waves due to the resonant interaction with cosmic ray particles may terminate the Kraichnan-type cascade below wavelengths 10{sup 13} cm. The effect of this wave dissipation has been incorporated in the GALPROP numerical propagation code in order to asses the impact on measurable astrophysical data. The energy-dependence of the cosmic-ray diffusion coefficient found in the resulting self-consistent model may explain the peaks in the secondary to primary nuclei ratios observed at about 1 GeV/nucleon.

Ptuskin, V.S.; /Troitsk, IZMIRAN /Maryland U.; Moskalenko, Igor V.; /Stanford U., HEPL; Jones, F.C.; /NASA, Goddard; Strong, A.W.; /Garching, Max Planck Inst., MPE; Zirakashvili, V.N.; /Troitsk, IZMIRAN /Heidelberg, Max Planck Inst. Astron.

2006-01-17

296

Electron-impact ionization of diatomic molecules using a configuration-average distorted-wave method  

SciTech Connect

Electron-impact ionization cross sections for diatomic molecules are calculated in a configuration-average distorted-wave method. Core bound orbitals for the molecular ion are calculated using a single-configuration self-consistent-field method based on a linear combination of Slater-type orbitals. The core bound orbitals are then transformed onto a two-dimensional (r,{theta}) numerical lattice from which a Hartree potential with local exchange is constructed. The single-particle Schroedinger equation is then solved for the valence bound orbital and continuum distorted-wave orbitals with S-matrix boundary conditions. Total cross section results for H{sub 2} and N{sub 2} are compared with those from semiempirical calculations and experimental measurements.

Pindzola, M. S.; Robicheaux, F.; Colgan, J.; Ballance, C. P. [Department of Physics, Auburn University, Auburn, Alabama 36849 (United States); Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Department of Physics, Rollins College, Winter Park, Florida 32789 (United States)

2007-07-15

297

Functional data analytic approach of modeling ECG T-wave shape to measure cardiovascular behavior  

E-print Network

The T-wave of an electrocardiogram (ECG) represents the ventricular repolarization that is critical in restoration of the heart muscle to a pre-contractile state prior to the next beat. Alterations in the T-wave reflect various cardiac conditions; and links between abnormal (prolonged) ventricular repolarization and malignant arrhythmias have been documented. Cardiac safety testing prior to approval of any new drug currently relies on two points of the ECG waveform: onset of the Q-wave and termination of the T-wave; and only a few beats are measured. Using functional data analysis, a statistical approach extracts a common shape for each subject (reference curve) from a sequence of beats, and then models the deviation of each curve in the sequence from that reference curve as a four-dimensional vector. The representation can be used to distinguish differences between beats or to model shape changes in a subject's T-wave over time. This model provides physically interpretable parameters characterizing T-wave sh...

Zhou, Yingchun; 10.1214/09-AOAS273

2010-01-01

298

Current management of functional dyspepsia: impact of Rome III subdivision  

PubMed Central

Functional dyspepsia (FD) is a highly prevalent disease characterized by symptoms originating from the gastroduodenal region in the absence of underlying organic disease. The Rome III consensus made a distinction between meal-induced and meal-unrelated symptoms and proposed subdivision of FD into postprandial distress syndrome and epigastric pain syndrome. The applicability of this subdivision and the impact on management are areas of active research. So far, empirical approaches are still employed for the treatment of FD, although various therapeutic modalities for FD have been explored; acid-suppressive, prokinetic, and fundic relaxant drugs, antidepressants and psychological therapies. FD remains a challenge and presents unmet clinical needs. PMID:24714074

Karamanolis, Georgios P.; Tack, Jan

2012-01-01

299

The Impact of Heat Islands on Mortality in Paris during the August 2003 Heat Wave  

PubMed Central

Background: Heat waves have a drastic impact on urban populations, which could increase with climate change. Objectives: We evaluated new indicators of elderly people’s exposure to heat in Paris, from a public health prevention perspective, using satellite thermal images. Methods: We used a time series of 61 images from the satellites of the National Oceanic and Atmospheric Administration’s (NOAA) Advanced Very High Resolution Radiometer (AVHRR) taken from 1 to 13 August 2003 to produce thermal indicators of minimum, maximum, and mean surface temperatures and diurnal temperature amplitude, with different lags between the meteorological data and the health impact. Health data came from a case–control study involving 241 people ? 65 years of age who died in the city of Paris or the nearby suburban area of Val-de-Marne during the August 2003 heat wave, and 241 controls who were matched to cases on age, sex, and residential zone. For each person, we integrated the thermal indicators in a conditional logistic regression model, adjusted for age and other potential confounders. We computed odds ratios (ORs) comparing the 90th and 50th percentiles of the temperature differences between cases and controls for various indicators. Results: Mortality risk was significantly associated with exposure for two indicators: minimum temperatures averaged for 1–13 August [for a 0.41°C increase, OR = 2.17; 95% confidence interval (CI): 1.14, 4.16] and minimum temperature averaged on the day of death and the 6 preceding days (for a 0.51°C increase: OR = 2.24; 95% CI: 1.03, 4.87). Conclusions: Our results support the influence of night temperatures on the health impact of heat waves in urban areas. Urban heat exposure indicators based on satellite imagery have the potential to identify areas with higher risk of death, which could inform intervention decisions by key stakeholders. PMID:21885383

Zeghnoun, Abdelkrim; Dousset, Benedicte; Bretin, Philippe; Vandentorren, Stephanie; Giraudet, Emmanuel; Beaudeau, Pascal

2011-01-01

300

Impact of wave front and coherence optimization in coherent diffractive imaging.  

PubMed

We present single shot nanoscale imaging using a table-top femtosecond soft X-ray laser harmonic source at a wavelength of 32 nm. We show that the phase retrieval process in coherent diffractive imaging critically depends on beam quality. Coherence and image fidelity are measured from single-shot coherent diffraction patterns of isolated nano-patterned slits. Impact of flux, wave front and coherence of the soft X-ray beam on the phase retrieval process and the image quality are discussed. After beam improvements, a final image reconstruction is presented with a spatial resolution of 78 nm (half period) in a single 20 fs laser harmonic shot. PMID:23670000

Ge, X; Boutu, W; Gauthier, D; Wang, F; Borta, A; Barbrel, B; Ducousso, M; Gonzalez, A I; Carré, B; Guillaumet, D; Perdrix, M; Gobert, O; Gautier, J; Lambert, G; Maia, F R N C; Hajdu, J; Zeitoun, P; Merdji, H

2013-05-01

301

Waves  

E-print Network

WAVES BY Mari LaCure Submitted to the graduate degree program in Visual Art and the Graduate Faculty of the University of Kansas in partial fulfillment of the requirements for the degree of Master’s of Fine Arts. Yoonmi Nam Chairperson... Committee members: Shawn Bitters Michael Krueger Date Defended: March 10, 2010 2 The Thesis Committee for Mari LaCure certifies that this is the approved Version of the following thesis: WAVES...

LaCure, Mari Mae

2010-04-29

302

A model for the probability density function of downwelling irradiance under ocean waves.  

PubMed

We present a statistical model that analytically quantifies the probability density function (PDF) of the downwelling light irradiance under random ocean waves modeling the surface as independent and identically distributed flat facets. The model can incorporate the separate effects of surface short waves and volume light scattering. The theoretical model captures the characteristics of the PDF, from skewed to near-Gaussian shape as the depth increases from shallow to deep water. The model obtains a closed-form asymptotic for the probability that diminishes at a rate between exponential and Gaussian with increasing extreme values. The model is validated by comparisons with existing field measurements and Monte Carlo simulation. PMID:21935119

Shen, Meng; Xu, Zao; Yue, Dick K P

2011-08-29

303

Quantum diffusion wave-function approach to two-dimensional vibronic spectroscopy  

NASA Astrophysics Data System (ADS)

We apply the quantum diffusion wavefunction approach to calculate vibronic two-dimensional (2D) spectra. As an example, we use a system consisting of two electronic states with harmonic oscillator potentials which are coupled to a bath and interact with three time-delayed laser pulses. The first- and second-order perturbative wave functions which enter into the expression for the third-order polarization are determined for a sufficient number of stochastic runs. The wave-packet approach, besides being an alternative technique to calculate the spectra, offers an intuitive insight into the dissipation dynamics and its relation to the 2D vibronic spectra.

Wehner, Johannes; Falge, Mirjam; Strunz, Walter T.; Engel, Volker

2014-10-01

304

Quantum diffusion wave-function approach to two-dimensional vibronic spectroscopy.  

PubMed

We apply the quantum diffusion wavefunction approach to calculate vibronic two-dimensional (2D) spectra. As an example, we use a system consisting of two electronic states with harmonic oscillator potentials which are coupled to a bath and interact with three time-delayed laser pulses. The first- and second-order perturbative wave functions which enter into the expression for the third-order polarization are determined for a sufficient number of stochastic runs. The wave-packet approach, besides being an alternative technique to calculate the spectra, offers an intuitive insight into the dissipation dynamics and its relation to the 2D vibronic spectra. PMID:25296805

Wehner, Johannes; Falge, Mirjam; Strunz, Walter T; Engel, Volker

2014-10-01

305

De Broglie wavelets versus Schroedinger wave functions: A ribbon model approach to quantum theory and the mechanisms of quantum interference  

SciTech Connect

As an alternative to better physical explanations of the mechanisms of quantum interference and the origins of uncertainty broadening, a linear hopping model is proposed with ``color-varying`` dynamics to reflect fast exchange between time-reversed states. Intricate relations between this model, particle-wave dualism, and relativity are discussed. The wave function is shown to possess dual characteristics of a stable, localized ``soliton-like`` de Broglie wavelet and a delocalized, interfering Schroedinger carrier wave function.

Tang, Jau

1996-02-01

306

Harmonic-oscillator excitations of precise few-body wave functions  

NASA Astrophysics Data System (ADS)

A method for calculating the occupation probability of the number of harmonic-oscillator (HO) quanta is developed for a precise few-body wave function obtained in a correlated Gaussian basis. The probability distributions of two- to four-nucleon wave functions obtained by using different nucleon-nucleon (NN) interactions are analyzed to gain insight into the characteristic behavior of the various interactions. Tensor correlations as well as short-range correlations play a crucial role in enhancing the probability of high HO excitations. For the excited states of He4, the interaction dependence is much less because high HO quanta are mainly responsible for describing the relative-motion function between the 3N +N (3H+p and 3He+n) clusters.

Horiuchi, W.; Suzuki, Y.

2014-09-01

307

A method for research on behaviour of a dimesoatomic wave function at small distances  

E-print Network

The Schr\\"odinger equation discribing the local potential model of a strong $\\pi^+\\pi^-$-interaction was studied. The influence of the strong $\\pi^+\\pi^-$-interaction of the behaviour of pionium nS-state wave functions at small distances is studied both analytically (perturbatively) and numerically. It is shown that in the whole the accounting of strong interaction results in multiplying pure Coulomb pionium wave functions by some function is practically independent of the value of the principal quantum number n. Due to this reason, the n-independence of probability of $\\pi^+\\pi^-$-atom production in nS-state remains the same as in the case of a pure Coulomb $\\pi^+\\pi^-$-interaction.

I. Amirkhanov; I. Puzynin; A. Tarasov; O. Voskresenskaya; O. Zeinalova

1998-12-09

308

A bound for the three-quark component of the nucleon wave function  

NASA Astrophysics Data System (ADS)

We constrain the probability for the three-quark component of the nucleon wave function by comparing its contribution to the deep-inelastic structure function data for F2( x). The three-quark wave function is constrained by QCD sum rules, i.e., its longitudinal projection has to agree with the Chernyak-Zhitnitski distribution amplitude moments. To relate the distribution amplitudes to F2( x) a specific model for the transverse momentum distribution is needed. We compare two such models and find that both give rather similar results. We conclude that the probability of finding only three quarks in a nucleon could be as large as (3-5)% for experimentally accessible values of Q2.

Schäfer, Andreas; Mankiewicz, Lech; Dziembowski, Zbigniew

1989-12-01

309

Harmonic-oscillator excitations of precise few-body wave functions  

E-print Network

A method for calculating the occupation probability of the number of harmonic oscillator (HO) quanta is developed for a precise few-body wave function obtained in a correlated Gaussian basis. The probability distributions of two- to four-nucleon wave functions obtained using different nucleon- nucleon (NN) interactions are analyzed to gain insight into the characteristic behavior of the various interactions. Tensor correlations as well as short-range correlations play a crucial role in enhancing the probability of high HO excitations. For the excited states of 4He, the interaction dependence is much less because high HO quanta are mainly responsible for describing the relative motion function between the 3N+N (3H+p and 3He+n) clusters.

W. Horiuchi; Y. Suzuki

2014-08-21

310

Effect of wave-function localization on the time delay in photoemission from surfaces  

NASA Astrophysics Data System (ADS)

We investigated streaking time delays in the photoemission from a solid model surface as a function of the degree of localization of the initial-state wave functions [1]. We consider a 1D slab with lattice constant alatt of attractive Gaussian-shaped core potentials of width ?. The parameter ? / alatt thus controls the localization of the electronic eigenfunctions. Small values of ? / alatt <<1 yield lattice eigenfunctions that consist of localized atomic wave functions modulated by a ``Bloch-envelope'' function, while the eigenfunctions become delocalized for larger values of ? / alatt > 0.4. From calculated photoemission spectra we deduced a characteristic bimodal shape of the band-averaged photoemission time delay: as the slab eigenfunctions become increasingly delocalized, the time delay quickly decreases near ? / alatt = 0.3. This change in wave-function localization facilitates the interpretation of a recently measured apparent relative time delay [2] between the photoemission from core and conduction-band levels of a tungsten surface [3]. [4pt] [1] C.-H. Zhang and U. Thumm, Phys. Rev. A 84, 065403 (2011).[0pt] [2] C.-H. Zhang and U. Thumm, Phys. Rev. A 84, 033401 (2011).[0pt] [3] C.-H. Zhang and U. Thumm , Phys. Rev. Lett. 102, 123601 (2009).

Thumm, Uwe; Zhang, Chanh-Hua

2012-06-01

311

Fine S wave velocity structure beneath Iwate volcano, northeastern Japan, as derived from receiver functions and travel times  

Microsoft Academic Search

A genetic algorithm inversion of receiver functions derived from a dense seismic network around Iwate volcano, northeastern Japan, provides the fine S wave velocity structure of the crust and uppermost mantle. Since receiver functions are insensitive to an absolute velocity, travel times of P and S waves propagating vertically from earthquakes in the subducting slab beneath the volcano are involved

Haruhisa Nakamichi; Satoru Tanaka; Hiroyuki Hamaguchi

2002-01-01

312

Numerically stable iterative method for the inversion of wave-front aberrations from measured point-spread-function data  

Microsoft Academic Search

This paper outlines a method for the determination of the unknown wave-front aberration function of an optical system from noisy measurements of the corresponding point-spread function. The problem is cast as a nonlinear least-squares estimation problem for the values of the wave-front aberration function at N points over the slit aperture, from measurements of the point-spread function at M points

Richard Barakat; Garry Newsam

1980-01-01

313

On the Quantum Mechanical Wave Function as a Link Between Cognition and the Physical World A Role for Psychology  

E-print Network

A straightforward explanation of fundamental tenets of quantum mechanics concerning the wave function results in the thesis that the quantum mechanical wave function is a link between human cognition and the physical world. The reticence on the part of physicists to adopt this thesis is discussed. A comparison is made to the behaviorists' consideration of mind, and the historical roots of how the problem concerning the quantum mechanical wave function arose are discussed. The basis for an empirical demonstration that the wave function is a link between human cognition and the physical world is provided through developing an experiment using methodology from psychology and physics. Based on research in psychology and physics that relied on this methodology, it is likely that Einstein, Podolsky, and Rosen's theoretical result that mutually exclusive wave functions can simultaneously apply to the same concrete physical circumstances can be implemented on an empirical level.

Snyder, D

2002-01-01

314

Expansion of X-ray form factor for close shell using uncorrelated wave function  

SciTech Connect

The atomic scattering factor has been studied for Be+ve, and B+2ve ions using the uncorrelated wave function (Hartree-Fock (HF)) for inter particle electronic shells. The physical importance of this factor appears in its relation to several important atomic properties as, the coherent scattering intensity, the total scattering intensity, the incoherent scattering function, the coherent scattering cross section, the total incoherent cross section, the nuclear magnetic shielding constant, the geometrical structure factor. Also there is one atomic properties the one particle radial density distribution function D(r)has been studied using the partitioning technique.

AL-Robayi, Enas M. [Babylon University , College of Science for Women, laser Physics Department, Hilla (Iraq)

2013-12-16

315

Assessments of Arterial Stiffness and Endothelial Function Using Pulse Wave Analysis  

PubMed Central

Conventionally, the assessments of endothelial function and arterial stiffness require different sets of equipment, making the inclusion of both tests impractical for clinical and epidemiological studies. Pulse wave analysis (PWA) provides useful information regarding the mechanical properties of the arterial tree and can also be used to assess endothelial function. PWA is a simple, valid, reliable, and inexpensive technique, offering great clinical and epidemiological potential. The current paper will outline how to measure arterial stiffness and endothelial function using this technique and include discussion of validity and reliability. PMID:22666595

Stoner, Lee; Young, Joanna M.; Fryer, Simon

2012-01-01

316

Coupling of surge and waves for an Ivan-like hurricane impacting the Tampa Bay, Florida region  

NASA Astrophysics Data System (ADS)

The interactions between waves and storm surge are investigated using an unstructured grid, coupled wave-surge model forced by a hypothetical Ivan-like hurricane impacting the Tampa Bay, Florida region. The waves derived from the unstructured version of the third-generation wave model simulating waves nearshore. The surge derives from the unstructured Finite-Volume Coastal Ocean Model, to which wave-induced forces (based on radiation stress theory) are added to the traditional forces by winds and atmospheric pressure. Dependent upon complex bathymetry and geometry, the wave-induced forces result in an additional 0.3˜0.5 m of surge relative to an uncoupled, surge-only simulation, and the increase in coastal sea level by the storm surge adds some 1.0˜1.5 m to the significant wave heights nearshore. Such strong interactions through coupling suggest that waves should not be omitted in hurricane storm surge simulations, especially because the forces by waves on coastal structures are perhaps the most damaging of the hurricane related forces.

Huang, Yong; Weisberg, Robert H.; Zheng, Lianyuan

2010-12-01

317

Reliability assessment of different plate theories for elastic wave propagation analysis in functionally graded plates.  

PubMed

The importance of elastic wave propagation problem in plates arises from the application of ultrasonic elastic waves in non-destructive evaluation of plate-like structures. However, precise study and analysis of acoustic guided waves especially in non-homogeneous waveguides such as functionally graded plates are so complicated that exact elastodynamic methods are rarely employed in practical applications. Thus, the simple approximate plate theories have attracted much interest for the calculation of wave fields in FGM plates. Therefore, in the current research, the classical plate theory (CPT), first-order shear deformation theory (FSDT) and third-order shear deformation theory (TSDT) are used to obtain the transient responses of flexural waves in FGM plates subjected to transverse impulsive loadings. Moreover, comparing the results with those based on a well recognized hybrid numerical method (HNM), we examine the accuracy of the plate theories for several plates of various thicknesses under excitations of different frequencies. The material properties of the plate are assumed to vary across the plate thickness according to a simple power-law distribution in terms of volume fractions of constituents. In all analyses, spatial Fourier transform together with modal analysis are applied to compute displacement responses of the plates. A comparison of the results demonstrates the reliability ranges of the approximate plate theories for elastic wave propagation analysis in FGM plates. Furthermore, based on various examples, it is shown that whenever the plate theories are used within the appropriate ranges of plate thickness and frequency content, solution process in wave number-time domain based on modal analysis approach is not only sufficient but also efficient for finding the transient waveforms in FGM plates. PMID:23714123

Mehrkash, Milad; Azhari, Mojtaba; Mirdamadi, Hamid Reza

2014-01-01

318

Development of a shock wave adhesion test for composite bonds by pulsed laser and mechanical impacts  

NASA Astrophysics Data System (ADS)

Evaluating the bonding quality of composite material is becoming one of the main challenges faced by aeronautic industries. This work aims to the development of a technique using shock wave, which would enable to quantify the bonding mechanical quality. Laser shock experiments were carried out. This technique enables high tensile stress generation in the thickness of composite bonds. The resulting damage has been quantified using different methods such as confocal microscopy, ultrasound and cross section observation. The discrimination between a correct bond and a weak bond was possible thanks to these experiments. Nevertheless, laser sources are not well adapted for optimization of such a test because of often fixed settings. That is why mechanical impacts on bonded composites were also performed in this work. By changing the thickness of aluminum projectiles, the generated tensile stresses by the shock wave propagation were moved toward the composite/bond interface. The made observations prove that the technique optimization is possible. The key parameters for the development of a bonding test using shock waves have been identified.

Ecault, R.; Boustie, M.; Touchard, F.; Arrigoni, M.; Berthe, L.

2014-05-01

319

Physical meaning and a duality of concepts of wave function, action functional, entropy, the Pointing vector, the Einstein tensor  

E-print Network

Physical meaning and a duality of concepts of wave function, action functional, entropy, the Pointing vector, the Einstein tensor and so on can be disclosed by investigating the state of material systems such as thermodynamic and gas dynamic systems, systems of charged particles, cosmologic systems and others. These concepts play a same role in mathematical physics. They are quantities that specify a state of material systems and also characteristics of physical fields. The duality of these concepts reveals in the fact that they can at once be both functionals and state functions or potentials. As functionals they are defined on nonintegrable manifold (for example, on tangent one), and as a state function they are defined on integrable manifold (for example, on cotangent one). The transition from functionals to state functions dicribes the mechanism of physical structure origination. The properties of these concepts can be studied by the example of entropy and action. The role of these concepts in mathematical physics and field theory will be demonstrated. Such results have been obtained by using skew-symmetric forms. In addition to exterior forms, the skew-symmetric forms, which are obtained from differential equations and, in distinction to exterior forms, are evolutionary ones and are defined on nonintegrable manifolds, were used.

L. I. Petrova

2010-01-11

320

Combined impacts of global warming and pollution: impacts on food web structure and ecosystem function.  

NASA Astrophysics Data System (ADS)

Effects of global species loss on ecosystem function have traditionally been extrapolated from studies which investigate the effect of random species loss or addition. Real species loss is highly patterned and clumped according to trophic position, taxonomic relatedness and interconnectedness with the remainder of the food web. Using pond microcosms, I evoked a realistic pattern of species loss using toxins and warming. Species loss was predictably highly patterned. Influences on ecosystem functions ranged from simple and linear in the case of algal productivity, through to complex and step-like in the case of bacterial decomposition. Impacts on algal productivity were mediated by effects on the rate of grazing by invertebrates. There is strong evidence from the bacterial decomposition results of an `insurance effect' whereby the presence of multiple stressors has a strong, non-additive effect on function. These results clearly show that the traditional ecotoxicological practice of studying effects of single toxins on single species may be highly misleading.

Thompson, R. M.

2005-05-01

321

The seismic response of an aquifer to the propagation of an impact generated shock wave: A possible trigger of the Martian outflow channels?  

NASA Technical Reports Server (NTRS)

Aquifer dilation from shock waves produced by the 8.4 magnitude Alaskan earthquake of 1964 led to water and sediment ejection from the ground up to 400 km away from the earthquake's epicenter. Groundwater disturbances were observed as far away as Perry, Florida (approximately 5500 km), where well water fluctuations with an amplitude of as much as 2.3 m were reported. The martian cratering record provides evidence that the planet has experienced numerous seismic events of a similar, and often much greater, magnitude. Given this fact, and the photogeologic evidence for abundant water in the early crust, the response of a basalt aquifer to the propagation of compressional waves (P-waves) produced by impacts in the 33-1000 km diameter size range were investigated. The resulting one-dimensional changes in effective stress and pore pressure were calculated - as a function of both distance and time - based on the following assumptions: (1) that all of the seismic energy radiated by an impact is transmitted as a single compressional wave; (2) that both the host rock and groundwater are compressible; and (3) that there is no net flow between the water-filled pores.

Leyva, Ivett A.; Clifford, Stephen M.

1993-01-01

322

Love waves in functionally graded piezoelectric materials by stiffness matrix method.  

PubMed

A numerical matrix method relative to the propagation of ultrasonic guided waves in functionally graded piezoelectric heterostructure is given in order to make a comparative study with the respective performances of analytical methods proposed in literature. The preliminary obtained results show a good agreement, however numerical approach has the advantage of conceptual simplicity and flexibility brought about by the stiffness matrix method. The propagation behaviour of Love waves in a functionally graded piezoelectric material (FGPM) is investigated in this article. It involves a thin FGPM layer bonded perfectly to an elastic substrate. The inhomogeneous FGPM heterostructure has been stratified along the depth direction, hence each state can be considered as homogeneous and the ordinary differential equation method is applied. The obtained solutions are used to study the effect of an exponential gradient applied to physical properties. Such numerical approach allows applying different gradient variation for mechanical and electrical properties. For this case, the obtained results reveal opposite effects. The dispersive curves and phase velocities of the Love wave propagation in the layered piezoelectric film are obtained for electrical open and short cases on the free surface, respectively. The effect of gradient coefficients on coupled electromechanical factor, on the stress fields, the electrical potential and the mechanical displacement are discussed, respectively. Illustration is achieved on the well known heterostructure PZT-5H/SiO(2), the obtained results are especially useful in the design of high-performance acoustic surface devices and accurately prediction of the Love wave propagation behaviour. PMID:21035829

Ben Salah, Issam; Wali, Yassine; Ben Ghozlen, Mohamed Hédi

2011-04-01

323

Impact of nonlinear waves on the dissipation of internal tidal energy at a shelf break  

NASA Astrophysics Data System (ADS)

The vertical and temporal structure of the dissipation of turbulent kinetic energy within the internal tide at a location 5 km shoreward of the shelf break on the Malin Shelf has been determined using a combination of the free-falling light yo-yo profiler and acoustic doppler current profilers. Two distinct internal wave regimes were encountered: period I in which large-amplitude high-frequency nonlinear internal waves (NIWs) occurred (around neap tides) and period II in which the internal wave spectral continuum was not dominated by any particular frequency band (around spring tides). Empirical orthogonal function analysis shows that for the low-frequency waves, 76% of the variance was described by mode 1, rising to 95% for the high-frequency waves. During period I the dissipation and vertical mixing were characterized by the NIWs, and 70% of the dissipation occurred in the bottom boundary layer. During period II the depth-integrated dissipation was more evenly distributed throughout the tidal cycle, whereas vertical mixing was greatly enhanced during a single hour long episode of elevated thermocline dissipation coincident with weakened stratification. During both periods I and II ˜30% of the total measured dissipation occurred within the thermocline when averaged over 12.4 hours; the remainder occurred within the bottom boundary layer(BBL). Tidal average values for depth-integrated dissipation and vertical eddy diffusivity for period I (II) were 1.1×10-2 W m-2 (4.0×10-2 W m-2) and 5 cm2 s-1 (12 cm2 s-1), respectively. Decay rates and internal damping are discussed, and vertical heat fluxes are estimated. Observed dissipation rates are compared with a simple model for BBL dissipation.

Inall, Mark E.; Rippeth, Tom P.; Sherwin, Toby J.

2000-04-01

324

Performance of storm damage functions: a sectoral impact model intercomparison  

NASA Astrophysics Data System (ADS)

Winter storms are the most costly natural hazard for European residential property. We compare four distinct storm damage functions with respect to their forecast accuracy and variability, with particular regard to the most severe winter storms. The analysis focuses on daily loss estimates under differing spatial aggregation, ranging from district to country level. We discuss the broad and heavily skewed distribution of insured losses posing difficulties on both the calibration and the evaluation of damage functions. From theoretical considerations, we provide a synthesis between the frequently discussed cubic damage-wind relationship and recent studies that report much steeper damage functions for European winter storms. The performance of the storm loss models is evaluated for two wind data sources, direct observation by the German Weather Service and ERA Interim reanalysis data. While the choice of wind data indicates little impact for the evaluation of German storm loss, local variability exhibits dependence between model and data choices. Based on our analysis, we favour the application of two probabilistic approaches which fare best in terms of the accuracy of their expected value and overall exhibit the lowest amount of variability.

Prahl, B. F.; Rybski, D.; Burghoff, O.; Kropp, J. P.

2014-09-01

325

Catastrophic impact of typhoon waves on coral communities in the Ryukyu Islands under global warming  

NASA Astrophysics Data System (ADS)

Typhoon-generated storm waves generally cause mechanical damage to coral communities on present-day reefs, and the magnitude and extent of damage is predicted to increase in the near future as a result of global warming. Therefore, a comprehensive understanding of potential future scenarios of reef ecosystems is of prime interest. This study assesses the current status of coral communities on Ibaruma reef, Ryukyu Islands, on the basis of field observations, engineering and fluid dynamic models, and calculations of wave motion, and predicts the potential effects of a super-extreme typhoon (incident wave height,H = 20 m; wave period, T = 20 s) on the reef. On the present-day reef, massive corals occur in shallow lagoons and tabular corals occur from the reef crest to the reef slope. The observed distribution of corals, which is frequently attacked by moderate (H = 10 m, T = 10 s) and extreme (H = 10 m, T = 15 s) typhoons, is consistent with the predictions of engineering models. Moreover, this study indicates that if a super-extreme typhoon attacks the reef in the near future, massive corals will survive in the shallow lagoons but tabular corals on the reef crest and reef slope will be severely impacted. The findings imply that super-extreme typhoons will cause a loss of species diversity, as the tabular corals are important reef builders and are critical to the maintenance of reef ecosystems. Consequently, reef restoration is a key approach to maintaining reef ecosystems in the wake of super-extreme typhoons.

Hongo, Chuki; Kawamata, Hideki; Goto, Kazuhisa

2012-06-01

326

Modeling the functional network of primary intercellular Ca$^{2+}$ wave propagation in astrocytes and its application to study drug effects  

E-print Network

We introduce a simple procedure of multivariate signal analysis to uncover the functional connectivity among cells composing a living tissue and describe how to apply it for extracting insight on the effect of drugs in the tissue. The procedure is based on the covariance matrix of time resolved activity signals. By determining the time-lag that maximizes covariance, one derives the weight of the corresponding connection between cells. Introducing simple constraints, it is possible to conclude whether pairs of cells are functionally connected and in which direction. After testing the method against synthetic data we apply it to study intercellular propagation of Ca$^{2+}$ waves in astrocytes following an external stimulus, with the aim of uncovering the functional cellular connectivity network. Our method proves to be particularly suited for this type of networking signal propagation where signals are pulse-like and have short time-delays, and is shown to be superior to standard methods, namely a multivariate Granger algorithm. Finally, based the statistical analysis of the connection weight distribution, we propose simple measures for assessing the impact of drugs on the functional connectivity between cells.

Marcelo Pires; Frank Raischel; Sandra Vaz; Andreia Cruz-Silva; Ana Sebastião; Pedro G. Lind

2013-11-27

327

The Transfer Function Model (TFM) as a Tool for Simulating Gravity Wave Phenomena in the Mesosphere  

NASA Astrophysics Data System (ADS)

The Transfer Function Model (TFM) is semi-analytical and linear, and it is designed to describe the acoustic gravity waves (GW) propagating over the globe and from the ground to 600 km under the influence of vertical temperature variations. Wave interactions with the flow are not accounted for. With an expansion in terms of frequency-dependent spherical harmonics, the time consuming vertical integration of the conservation equations is reduced to computing the transfer function (TF). (The applied lower and upper boundary conditions assure that spurious wave reflections will not occur.) The TF describes the dynamical properties of the medium divorced from the complexities of the temporal and horizontal variations of the excitation source. Given the TF, the atmospheric response to a chosen source is then obtained in short order to simulate the GW propagating through the atmosphere over the globe. In the past, this model has been applied to study auroral processes, which produce distinct wave phenomena such as: (1) standing lamb modes that propagate horizontally in the viscous medium of the thermosphere, (2) waves generated in the auroral oval that experience geometric amplification propagating to the pole where constructive interference generates secondary waves that propagate equatorward, (3) ducted modes propagating through the middle atmosphere that leak back into the thermosphere, and (4) GWs reflected from the Earth's surface that reach the thermosphere in a narrow propagation cone. Well-defined spectral features characterize these wave modes in the TF to provide analytical understanding. We propose the TFM as a tool for simulating GW in the mesosphere and in particular the features observed in Polar Mesospheric Clouds (PMC). With present-day computers, it takes less than one hour to compute the TF, so that there is virtually no practical limitation on the source configurations that can be applied and tested in the lower atmosphere. And there is no limitation on the temporal and spatial resolutions the model simulations can provide. We shall discuss the concept and organization of the TFM and present samples of GW simulations that illustrate the capabilities of the model and its user interface. We shall discuss in particular the waves that leak into the mesopause from the thermosphere above and propagate into the region from tropospheric weather systems below.

Porter, H.; Mayr, H.; Moore, J.; Wilson, S.; Armaly, A.

2008-12-01

328

The impact of functionalization on the stability, work function, and photoluminescence of reduced graphene oxide.  

PubMed

Reduced graphene oxide (rGO) is a promising material for a variety of thin-film optoelectronic applications. Two main barriers to its widespread use are the lack of (1) fabrication protocols leading to tailored functionalization of the graphene sheet with oxygen-containing chemical groups, and (2) understanding of the impact of such functional groups on the stability and on the optical and electronic properties of rGO. We carry out classical molecular dynamics and density functional theory calculations on a large set of realistic rGO structures to decompose the effects of different functional groups on the stability, work function, and photoluminescence. Our calculations indicate the metastable nature of carbonyl-rich rGO and its favorable transformation to hydroxyl-rich rGO at room temperature via carbonyl-to-hydroxyl conversion reactions near carbon vacancies and holes. We demonstrate a significant tunability in the work function of rGO up to 2.5 eV by altering the composition of oxygen-containing functional groups for a fixed oxygen concentration, and of the photoluminescence emission by modulating the fraction of epoxy and carbonyl groups. Taken together, our results guide the application of tailored rGO structures in devices for optoelectronics and renewable energy. PMID:23368710

Kumar, Priyank V; Bernardi, Marco; Grossman, Jeffrey C

2013-02-26

329

Two-component natural spinors from two-step spin-orbit coupled wave functions.  

PubMed

We developed an algorithm to obtain the natural orbitals (natural spinors) from the two-step spin-orbit coupled wave functions. These natural spinors are generally complex-valued, mixing two spin components, and they can have similar symmetry properties as the j-j spinors from the one-step spin-orbit coupling calculations, if the reduced density equally averages all the components of a multi-dimensional irreducible representation. Therefore, the natural spinors can serve as an approximation to the j-j spinors and any wave function analysis based on the j-j spinors can also be performed based on them. The comparison between the natural spinors and the j-j spinors of three representative atoms, Tl, At, and Lu, shows their close similarity and demonstrates the ability of the natural spinors to approximate the j-j spinors. PMID:21663344

Zeng, Tao; Fedorov, Dmitri G; Schmidt, Michael W; Klobukowski, Mariusz

2011-06-01

330

Robustness of the vacuum wave function and other matters for Yang-Mills theory  

SciTech Connect

In the first part of this paper, we present a set of simple arguments to show that the two-dimensional gauge anomaly and the (2+1)-dimensional Lorentz symmetry determine the leading Gaussian term in the vacuum wave function of (2+1)-dimensional Yang-Mills theory. This is to highlight the robustness of the wave function and its relative insensitivity to the choice of regularizations. We then comment on the correspondence with the explicit calculations done in earlier papers. We also make some comments on the nature of the gauge-invariant configuration space for Euclidean three-dimensional gauge fields (relevant to (3+1)-dimensional Yang-Mills theory)

Karabali, Dimitra; Nair, V. P. [Department of Physics and Astronomy, Lehman College of the CUNY, Bronx, New York 10468 (United States); Physics Department, City College of the CUNY, New York, New York 10031 (United States)

2008-01-15

331

Further improvement in the variational many-body wave functions for light nuclei  

NASA Astrophysics Data System (ADS)

An improved variational ansatz is proposed and implemented for variational many-body wave functions for light nuclei with nucleons interacting through Argonne (AV18) and Urbana IX (UIX) three-nucleon interactions. The new ansatz is based upon variationally distinguishing between the various components of the two-body Jastrow and operatorial correlations, which are operated upon by three-body and spin-orbit correlations. We obtain noticeable improvement in the quality of the wave function and lowering of the energies compared to earlier results. The new energies are -8.38(1), -28.07(1), and -29.90(1) MeV for 3H, 4He, and 6Li, respectively. Though, the present improved ansatz still fails to stabilize the 6Li nucleus against a breakup into an ? particle and a deuteron by 390 KeV; nonetheless, it is an improvement over previous studies.

Usmani, Q. N.; Anwar, K.; Abdullah, Nooraihan

2012-09-01

332

Velocity and attenuation of scalar and elastic waves in random media: a spectral function approach.  

PubMed

This paper investigates the scattering of scalar and elastic waves in two-phase materials and single-mineral-cubic, hexagonal, orthorhombic-polycrystalline aggregates with randomly oriented grains. Based on the Dyson equation for the mean field, explicit expressions for the imaginary part of Green's function in the frequency-wavenumber domain (?, p), also known as the spectral function, are derived. This approach allows the identification of propagating modes with their relative contribution, and the computation of both attenuation and phase velocity for each mode. The results should be valid from the Rayleigh (low-frequency) to the geometrical optics (high-frequency) regime. Comparisons with other approaches are presented for both scalar and elastic waves. PMID:22423683

Calvet, Marie; Margerin, Ludovic

2012-03-01

333

Is a system's wave function in one-to-one correspondence with its elements of reality?  

E-print Network

Although quantum mechanics is one of our most successful physical theories, there has been a long-standing debate about the interpretation of the wave function---the central object of the theory. Two prominent views are that (i) it corresponds to an element of reality, i.e. an objective attribute that exists before measurement, and (ii) it is a subjective state of knowledge about some underlying reality. A recent result [Pusey et al. arXiv:1111.3328] has placed the subjective interpretation into doubt, showing that it would contradict certain physically plausible assumptions, in particular that multiple systems can be prepared such that their elements of reality are uncorrelated. Here we show, based only on the assumption that measurement settings can be chosen freely, that a system's wave function is in one-to-one correspondence with its elements of reality. This also eliminates the possibility that it can be interpreted subjectively.

Roger Colbeck; Renato Renner

2011-11-28

334

Second-order corrections to the wave function at the origin in muonic hydrogen and pionium  

SciTech Connect

Nonrelativistic second-order corrections to the wave function at the origin in muonic and exotic atoms are considered. The corrections are due to the electronic vacuum polarization. Such corrections are of interest due to various effective approaches, which take into account QED and hadronic effects. The wave function at the origin plays a key role in the calculation of the pionium lifetime, various finite nuclear size effects, and the hyperfine splitting. The results are obtained for the 1s and 2s states in pionic and muonic hydrogen and deuterium and in pionium, a bound system of {pi}{sup +} and {pi}{sup -}. Applications to the hyperfine structure and the Lamb shift in muonic hydrogen are also considered.

Ivanov, Vladimir G.; Korzinin, Evgeny Yu.; Karshenboim, Savely G. [Pulkovo Observatory, 196140, St. Petersburg, Russia and D. I. Mendeleev Institute for Metrology (VNIIM), St. Petersburg 198005 (Russian Federation); D. I. Mendeleev Institute for Metrology (VNIIM), St. Petersburg 198005 (Russian Federation); D. I. Mendeleev Institute for Metrology (VNIIM), St. Petersburg 198005, Russia and Max-Planck-Institut fuer Quantenoptik, 85748 Garching (Germany)

2009-07-15

335

Compact wave function for bond dissociation and Van der Waals interactions: A natural amplitude assessment  

E-print Network

Electron correlations in molecules can be divided in short range dynamical correlations, long range Van der Waals type interactions and near degeneracy static correlations. In this work we analyze how these three types of correlations can be incorporated in a simple wave function of restricted functional form consisting of an orbital product multiplied by a single correlation function $f(r_{12})$ depending on the interelectronic distance $r_{12}$. Since the three types of correlations mentioned lead to different signatures in terms of the natural orbital (NO) amplitudes in two-electron systems we make an analysis of the wave function in terms of the NO amplitudes for a model system of a diatomic molecule. In our numerical implementation we fully optimize the orbitals and the correlation function on a spatial grid without restrictions on their functional form. For the model system we can prove that none of the amplitudes vanishes and moreover that it displays a distinct sign pattern and a series of avoided cro...

Giesbertz, K J H

2014-01-01

336

Waves generated by Asteroid impacts and their effects on US shorelines  

NASA Astrophysics Data System (ADS)

On February 15, 2013 an undetected ~17-20-m diameter asteroid entered earth's atmosphere and, due to its large entry speed of 18.6 km/s and its shallow entry angle, the asteroid exploded in an airburst over Chelyabinsk, Russia, generating a bright flash, producing many small fragment meteorites and causing a powerful shock wave which released the equivalent of ~440 kt TNT of energy. About 16 hours after the Chelyabinsk asteroid, the elongated ~20m by ~40m (~30 m diameter) NEA 2012 DA14 with an estimated mass of 40 kt neared the earth surface at ~28,100km, ~2.2 earth's diameter. These two consecutive events, which were unrelated and had drastically different orbits, generated considerable attention and awareness from the public, confusion among the local residents, and raised the issue of emergency response and preparedness of local, state and government agencies. LLNL and other government agencies have performed numerical simulations of a postulated asteroid impact onto the ocean and generated data to support an emergency preparedness exercise. We illustrate the exercise through the application of several codes from source (asteroid entry) to ocean impact (splash rim) to wave generation, propagation and interaction with the shoreline. Using state-of-the-art high performance computing codes we simulate three impact sites; one site is located off the eat coat by Maryland's shoreline and two other sites on the west coast: the San Francisco bay and the Los Angeles bay shorelines, respectively. Simulations were conducted not only under deterministic conditions but also under conditions of uncertainty. Uncertainty assessment of flood hazards zones and structural integrity of infrastructures will be presented. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344, and partially funded by the Laboratory Directed Research and Development Program at LLNL under tracking code 12-ERD-005.

Ezzedine, S. M.; Miller, P. L.; Dearborn, D. S.; Dennison, D. S.; Glascoe, L. G.; Antoun, T.

2013-12-01

337

Quantum Chemistry without Wave Functions: Diffusion Monte Carlo Applied to H and H2+  

Microsoft Academic Search

Although it is an exactly solvable problem, in a standard quantum chemistry course the quantum mechanical treatment of H2+ is usually done within the LCAO-MO approximation. Even allowing for variable orbital exponents in the wave function, the variational energy has a substantial error at the equilibrium bond distance. As a computer project associated with our basic third-year-level quantum chemistry course,

Heather L. Cuthbert; Stuart M. Rothstein

1999-01-01

338

Spatial imaging of the H2(+) vibrational wave function at the quantum limit.  

PubMed

We experimentally obtained a direct image of the nuclear wave functions of H(2)(+) by dissociating the molecule via electron attachment and determining the vibrational state using the cold target recoil ion momentum spectroscopy technique. Our experiment visualizes the nodal structure of different vibrational states. We compare our results to the widely used reflection approximation and to quantum simulations and discuss the limits of position measurements in molecules imposed by the uncertainty principle. PMID:22401202

Schmidt, L Ph H; Jahnke, T; Czasch, A; Schöffler, M; Schmidt-Böcking, H; Dörner, R

2012-02-17

339

Peaks in the Hartle-Hawking Wave Function from Sums over Topologies  

E-print Network

Recent developments in ``Einstein Dehn filling'' allow the construction of infinitely many Einstein manifolds that have different topologies but are geometrically close to each other. Using these results, we show that for many spatial topologies, the Hartle-Hawking wave function for a spacetime with a negative cosmological constant develops sharp peaks at certain calculable geometries. The peaks we find are all centered on spatial metrics of constant negative curvature, suggesting a new mechanism for obtaining local homogeneity in quantum cosmology.

M. Anderson; S. Carlip; J. Ratcliffe; S. Surya; S. Tschantz

2003-10-01

340

Peaks in the Hartle-Hawking Wave Function from Sums over Topologies  

E-print Network

Recent developments in ``Einstein Dehn filling'' allow the construction of infinitely many Einstein manifolds that have different topologies but are geometrically close to each other. Using these results, we show that for many spatial topologies, the Hartle-Hawking wave function for a spacetime with a negative cosmological constant develops infinite peaks at certain calculable geometries. The peaks we find are all centered on spatial metrics of constant negative curvature, suggesting a new mechanism for obtaining local homogeneity in quantum cosmology.

Anderson, M; Ratcliffe, J; Surya, S; Tschantz, S T

2004-01-01

341

Plane Wave Density Functional Model Studies of Chemistry at Surfaces  

Microsoft Academic Search

Quantum chemical studies on the hydrogenation of acrolein by means of a silver catalyst and the sorption of uranyl on kaolinite\\u000a are presented as examples of computational modeling of surface species and chemical processes at the atomic scale. A plane-wave\\u000a density functional approach as implemented in the parallel program package VASP was applied on supercell models of these surface\\u000a systems

Notker Rösch; Sven Krüger

342

Quantum statistical foundation to the Fermi liquid model and Ginzburg-Landau wave function  

SciTech Connect

An energy eigenvalue equation for a quasi-particle is derived, starting with the Heisenberg equation of motion for an annihilation operator. An elementary derivation of the Fermi liquid model having a sharply defined Fermi surface in the k-space is given, starting with a realistic model of a metal including the Coulomb interaction among and between electrons and lattice-ions. The Ginzburg-Landau wave function [Psi][sub [sigma

Fujita, Shigeji; Godoy, S. (UNAM, Mexico (Mexico))

1993-12-01

343

Does Laser Type Impact Myocardial Function Following Transmyocardial Laser Revascularization?  

PubMed Central

Background Transmyocardial laser revascularization (TMR) is currently clinically performed with either a CO2 or Ho:YAG laser for the treatment of severe angina. While both lasers provide symptomatic relief, there are significant differences in the laser–tissue interactions specific to each device that may impact their ability to enhance the perfusion of myocardium and thereby improve contractile function of the ischemic heart. Methods A porcine model of chronic myocardial ischemia was employed. After collecting baseline functional data with cine magnetic resonance imaging (MRI) and dobutamine stress echo (DSE), 14 animals underwent TMR with either a CO2 or Ho:YAG laser. Transmural channels were created with each laser in a distribution of 1/cm2 in the ischemic zone. Six weeks post-treatment repeat MRI as well as DSE were obtained after which the animals were sacrificed. Histology was preformed to characterize the laser–tissue interaction. Results CO2 TMR led to improvement in wall thickening in the ischemic area as seen with cine MRI (40.3% vs. baseline, P < 0.05) and DSE (20.2% increase vs. baseline, P < 0.05). Ho:YAG treated animals had no improvement in wall thickening by MRI (?11.6% vs. baseline, P = .67) and DSE (?16.7% vs. baseline, P = 0.08). Correlative semi-quantitative histology revealed a significantly higher fibrosis index in Ho:YAG treated myocardium versus CO2 (1.81 vs. 0.083, P < 0.05). Conclusions In a side-by-side comparison CO2 TMR resulted in improved function of ischemic myocardium as assessed by MRI and echocardiography. Ho:YAG TMR led to no improvement in regional function likely due to concomitant increase in fibrosis in the lasered area. PMID:21246579

Estvold, Soren K.; Mordini, Frederico; Zhou, Yifu; Yu, Zu X.; Sachdev, Vandana; Arai, Andrew; Horvath, Keith A.

2012-01-01

344

Finasteride-Its Impact on Sexual Function and Prostate Cancer  

PubMed Central

Finasteride, a specific and competitive inhibitor of 5?-reductase enzyme Type 2, inhibits the conversion of testosterone to dihydrotestosterone (DHT). In adults, DHT acts as primary androgen in prostate and hair follicles. The only FDA-approved dermatological indication of finasteride is androgenetic alopecia. But, apprehension regarding sexual dysfunction associated with finasteride deters dermatologists from prescribing the drug and patients from taking the drug for androgenetic alopecia. Testosterone, through its humoral endocrine and local paracrine effects is relevant in central and peripheral modulation of sexual function than locally acting DHT. Several large population-based long-term placebo-controlled studies, using International Index of Erectile Function-5 questionnaire and objective method (Nocturnal Penile Tumescence) to assess the erectile function have demonstrated no clear evidence of the negative effect of finasteride on erectile function. Reduction in ejaculatory volume is the only established causal relationship between finasteride and sexual dysfunction. Though finasteride causes significant reduction in all the semen parameters except sperm morphology, they did not fall below the threshold levels to interfere with fertility. Therefore, the sexual adverse effects associated with finasteride should be viewed in relation to normal prevalence and natural history of erectile dysfunction in the population, age of the patient, other confounding factors and also nocebo effect. The impact of finasteride on the prevention of prostate cancer has been discussed extensively. Finasteride is found to be effective in significantly reducing the incidence of low-grade prostate cancer. But the paradoxical increase in high-grade cancer in the finasteride group has been attributed to increased sensitivity and improved performance of prostate specific antigen levels to detect all grades of prostate cancer. PMID:20300365

Anitha, B; Inamadar, Arun C; Ragunatha, S

2009-01-01

345

Analytic calculation of energies and wave functions of the quartic and pure quartic oscillators  

SciTech Connect

Ground state energies and wave functions of quartic and pure quartic oscillators are calculated by first casting the Schroedinger equation into a nonlinear Riccati form and then solving that nonlinear equation analytically in the first iteration of the quasilinearization method (QLM). In the QLM the nonlinear differential equation is solved by approximating the nonlinear terms by a sequence of linear expressions. The QLM is iterative but not perturbative and gives stable solutions to nonlinear problems without depending on the existence of a smallness parameter. Our explicit analytic results are then compared with exact numerical and also with WKB solutions and it is found that our ground state wave functions, using a range of small to large coupling constants, yield a precision of between 0.1 and 1 percent and are more accurate than WKB solutions by two to three orders of magnitude. In addition, our QLM wave functions are devoid of unphysical turning point singularities and thus allow one to make analytical estimates of how variation of the oscillator parameters affects physical systems that can be described by the quartic and pure quartic oscillators.

Liverts, E. Z.; Mandelzweig, V. B.; Tabakin, F. [Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel); Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania 15260 (United States)

2006-06-15

346

Double-bound equivalent of the three-body Coulomb double-continuum wave function  

SciTech Connect

In cross-section calculations of electron or photon double ionization processes of two-electron atoms, it is desirable to have a symmetric description of initial and final states. In this contribution, we search the doubly bound analog, for S states, of the well-known and widely used three-body Coulomb (C3) double-continuum wave function. This is performed with two alternative approaches: through an analytic continuation of the C3 continuum and through a 'C3 approach' of the Hylleraas equation for S bound states. The double-bound analog consists of the product of two Coulomb bound states (one for each electron-nucleus interaction) multiplied by a Coulomb distortion factor which describes the electron-electron correlation. Our result differs from Pluvinage's wave function which is commonly misbelieved to be the bound counterpart of the C3 double continuum. With a rigorous treatment of the analytic continuation of the distortion factor, the double-bound equivalent of the C3 model is also found. Though the purpose is not to obtain good two-electron bound states, the found bound wave functions are tested, in the case of helium, through various local and mean quantities which probe different regions of the configuration space, in particular those close to the two-particle coalescence points.

Ancarani, L. U. [Laboratoire de Physique Moleculaire et des Collisions, Universite Paul Verlaine-Metz, 57078 Metz (France); Gasaneo, G. [Departamento de Fisica, Universidad Nacional del Sur and Consejo Nacional de Investigaciones Cientificas y Tecnicas, 8000 Bahia Blanca, Buenos Aires (Argentina)

2007-03-15

347

Emergence of complex and spinor wave functions in scale relativity. I. Nature of scale variables  

SciTech Connect

One of the main results of scale relativity as regards the foundation of quantum mechanics is its explanation of the origin of the complex nature of the wave function. The scale relativity theory introduces an explicit dependence of physical quantities on scale variables, founding itself on the theorem according to which a continuous and non-differentiable space-time is fractal (i.e., scale-divergent). In the present paper, the nature of the scale variables and their relations to resolutions and differential elements are specified in the non-relativistic case (fractal space). We show that, owing to the scale-dependence which it induces, non-differentiability involves a fundamental two-valuedness of the mean derivatives. Since, in the scale relativity framework, the wave function is a manifestation of the velocity field of fractal space-time geodesics, the two-valuedness of velocities leads to write them in terms of complex numbers, and yields therefore the complex nature of the wave function, from which the usual expression of the Schrödinger equation can be derived.

Nottale, Laurent; Célérier, Marie-Noëlle [LUTH, Observatoire de Paris, CNRS, Université Paris-Diderot, 5 place Jules Janssen, 92195 Meudon Cedex (France)] [LUTH, Observatoire de Paris, CNRS, Université Paris-Diderot, 5 place Jules Janssen, 92195 Meudon Cedex (France)

2013-11-15

348

Wave function for the squeezed atomic coherent state in entangled state representation and some of its applications  

NASA Astrophysics Data System (ADS)

Based on the Einstein, Podolsky, and Rosen (EPR) entangled state representation, this paper introduces the wave function for the squeezed atomic coherent state (SACS), which turns out to be just proportional to a single-variable ordinary Hermite polynomial of order 2j. As important applications of the wave function, the Wigner function of the SACS and its marginal distribution are obtained and the eigenproblems of some Hamiltonians for the generalized angular momentum system are solved.

Wang, Ji-Suo; Meng, Xiang-Guo; Liang, Bao-Long

2010-01-01

349

Splash wave and crown breakup after disc impact on a liquid surface  

NASA Astrophysics Data System (ADS)

In this paper we analyze the impact of a circular disc on a free surface using experiments, potential flow numerical simulations and theory. We focus our attention both on the study of the generation and possible breakup of the splash wave created after the impact and on the calculation of the force on the disc. We have experimentally found that drops are only ejected from the rim located at the top part of the splash --giving rise to what is known as the crown splash-- if the impact Weber number exceeds a threshold value $\\Weber_{crit}\\simeq 140$. We explain this threshold by defining a local Bond number $Bo_{tip}$ based on the rim deceleration and its radius of curvature, with which we show using both numerical simulations and experiments that a crown splash only occurs when $Bo_{tip}\\gtrsim 1$, revealing that the rim disrupts due to a Rayleigh-Taylor instability. Neglecting the effect of air, we show that the flow in the region close to the disc edge possesses a Weber-number-dependent self-similar structure for every Weber number. From this we demonstrate that $\\Bond_{tip}\\propto\\Weber$, explaining both why the transition to crown splash can be characterized in terms of the impact Weber number and why this transition occurs for $We_{crit}\\simeq 140$. Next, including the effect of air, we have developed a theory which predicts the time-varying thickness of the very thin air cushion that is entrapped between the impacting solid and the liquid. Our analysis reveals that gas critically affect the velocity of propagation of the splash wave as well as the time-varying force on the disc, $F_D$. The existence of the air layer also limits the range of times in which the self-similar solution is valid and, accordingly, the maximum deceleration experienced by the liquid rim, what sets the length scale of the splash drops ejected when $We>\\Weber_{crit}$.

Peters, Ivo R.; van der Meer, Devaraj; Gordillo, J. M.

2013-06-01

350

Acoustic wave propagation in continuous functionally graded plates: an extension of the Legendre polynomial approach.  

PubMed

The propagation of guided waves in continuous functionally graded plates is studied by using Legendre polynomials. Dispersion curves, and power and field profiles are easily obtained. Our computer program is validated by comparing our results against other calculations from the literature. Numerical results are also given for a graded semiconductor plate. It is felt that the present method could be of quite practical interest in waveguiding engineering, non-destructive testing of functionally graded materials (FGMs) to identify the best inspection strategies, or by means of a numerical inversion algorithm to determine through-thickness gradients in material parameters. PMID:11570758

Lefebvre, J E; Zhang, V; Gazalet, J; Gryba, T; Sadaune, V

2001-09-01

351

Modelling impact-initiated wave transmission through lung parenchyma in relation to the aetiology of exercise-induced pulmonary haemorrhage.  

PubMed

Recently we proposed that exercise-induced pulmonary haemorrhage (EIPH) results from locomotory-impact-induced trauma by impact of the scapula on the chest wall during footfall and the consequent transmission of waves through the lung. A computational model has been developed to demonstrate that wave amplification and focusing occur in the dorsocaudal tip of the lung for waves originating on the anterior subscapular surface. The propagation of an acoustic wave was investigated in a simplified 2-dimensional representation of a vertical anterio-dorsal section of horse lung. It was demonstrated that a complicated pattern of waves is transmitted from the scapula to the dorsal region. Wave motion was characterised using the instantaneous rate of change of pressure with time (dp/dt) which is associated with lung injury. Due to wave reflection and focusing, dp/dt is transiently very high on the spinal and diaphragmatic lung walls, particularly in the vicinity of the dorsal tip. The model therefore predicts that lung injury may occur in the region in which EIPH is reported to originate. PMID:10659218

Schroter, R C; Leeming, A; Denny, E; Bharath, A; Marlin, D J

1999-07-01

352

The Impact of Chromospheric Activity on Observed Initial Mass Functions  

NASA Astrophysics Data System (ADS)

Using recently established empirical calibrations for the impact of chromospheric activity on the radii, effective temperatures, and estimated masses of active low-mass stars and brown dwarfs, we reassess the shape of the initial mass function (IMF) across the stellar/substellar boundary in the Upper Sco star-forming region (age ~ 5-10 Myr). We adjust the observed effective temperatures to warmer values using the observed strength of the chromospheric H? emission, and redetermine the estimated masses of objects using pre-main-sequence evolutionary tracks in the H-R diagram. The effect of the activity-adjusted temperatures is to shift the objects to higher masses by 3%-100%. While the slope of the resulting IMF at substellar masses is not strongly changed, the peak of the IMF does shift from ?0.06 to ?0.11 M ?. Moreover, for objects with masses <~ 0.2 M ?, the ratio of brown dwarfs to stars changes from ~80% to ~33%. These results suggest that activity corrections are essential for studies of the substellar mass function, if the masses are estimated from spectral types or from effective temperatures.

Stassun, Keivan G.; Scholz, Aleks; Dupuy, Trent J.; Kratter, Kaitlin M.

2014-12-01

353

Human adipocyte function is impacted by mechanical cues.  

PubMed

Fibrosis is a hallmark of human white adipose tissue (WAT) during obesity-induced chronic inflammation. The functional impact of increased interstitial fibrosis (peri-adipocyte fibrosis) on adjacent adipocytes remains unknown. Here we developed a novel in vitro 3D culture system in which human adipocytes and decellularized material of adipose tissue (dMAT) from obese subjects are embedded in a peptide hydrogel. When cultured with dMAT, adipocytes showed decreased lipolysis and adipokine secretion and increased expression/production of cytokines (IL-6, G-CSF) and fibrotic mediators (LOXL2 and the matricellular proteins THSB2 and CTGF). Moreover, some alterations including lipolytic activity and fibro-inflammation also occurred when the adipocyte/hydrogel culture was mechanically compressed. Notably, CTGF expression levels correlated with the amount of peri-adipocyte fibrosis in WAT from obese individuals. Moreover, dMAT-dependent CTGF promoter activity, which depends on ?1-integrin/cytoskeleton pathways, was enhanced in the presence of YAP, a mechanosensitive co-activator of TEAD transcription factors. Mutation of TEAD binding sites abolished the dMAT-induced promoter activity. In conclusion, fibrosis may negatively affect human adipocyte function via mechanosensitive molecules, in part stimulated by cell deformation. PMID:24623048

Pellegrinelli, V; Heuvingh, J; du Roure, O; Rouault, C; Devulder, A; Klein, C; Lacasa, M; Clément, E; Lacasa, D; Clément, K

2014-06-01

354

Impact of shock wave lithotripsy on heart rate variability in patients with urolithiasis.  

PubMed

The physiological response of the cardiac autonomic nervous system during shock wave lithotripsy (SWL) remains unclear. Heart rate variability (HRV) is an index of cardiac autonomic balance. This study aimed to analyze HRV during SWL in patients with urolithiasis. Electrocardiograms of patients who underwent SWL were obtained. Recordings were obtained before and after SWL. For each time point, the recordings were obtained continuously for 6 min, after which R wave-to-R wave (RR) intervals were extracted. The time digital sequence derived from RR intervals was the HRV signal. Time-domain analysis revealed that the mean of RR intervals (MRR) and standard deviation of normal beat-to-normal beat (NN) intervals (SDNN), but not the square root of the mean squared difference of successive NNs (RMSSD) or triangular interpolation of NN intervals (TINN), significantly increased during SWL. The increase in SDNN persisted after SWL but MRR returned to the initial level. Frequency-domain analysis revealed that very low frequency (VLF), low frequency (LF), and LF/high frequency (HF) ratio significantly increased after SWL, while there was no statistically significant difference in HF. Thus, the patients had significantly high MRR and SDNN during SWL and significantly high SDNN, VLF, LF, and LF/HF ratio after SWL. SWL could alter the functioning of the cardiac autonomic nervous system, resulting in reduction in sympathetic activity and increase in parasympathetic activity. Further studies with larger samples are required to confirm these findings and understand the underlying mechanisms. PMID:20924572

Lin, Wu-Chou; Ho, Chien-Yi; Chen, Yung-Hsiang; Chen, I-Cheng; Chen, Huey-Yi; Tsai, Fuu-Jen; Shen, Jui-Lung; Man, Samantha Shan; Huang, Po-Hsun; Chen, Yuh-Lien; Man, Kee-Ming; Chen, Wen-Chi

2011-04-01

355

Acute effect of alcohol intake on sine-wave Cartesian and polar contrast sensitivity functions  

PubMed Central

The aim of this study was to assess contrast sensitivity for angular frequency stimuli as well as for sine-wave gratings in adults under the effect of acute ingestion of alcohol. We measured the contrast sensitivity function (CSF) for gratings of 0.25, 1.25, 2.5, 4, 10, and 20 cycles per degree of visual angle (cpd) as well as for angular frequency stimuli of 1, 2, 4, 24, 48, and 96 cycles/360°. Twenty adults free of ocular diseases, with normal or corrected-to-normal visual acuity, and no history of alcoholism were enrolled in two experimental groups: 1) no alcohol intake (control group) and 2) alcohol ingestion (experimental group). The average concentration of alcohol in the experimental group was set to about 0.08%. We used a paradigm involving a forced-choice method. Maximum sensitivity to contrast for sine-wave gratings in the two groups occurred at 4 cpd sine-wave gratings and at 24 and 48 cycles/360° for angular frequency stimuli. Significant changes in contrast sensitivity were observed after alcohol intake compared with the control condition at spatial frequency of 4 cpd and 1, 24, and 48 cycles/360° for angular frequency stimuli. Alcohol intake seems to affect the processing of sine-wave gratings at maximum sensitivity and at the low and high frequency ends for angular frequency stimuli, both under photopic luminance conditions. PMID:24676473

Cavalcanti-Galdino, M.K.; da Silva, J.A.; Mendes, L.C.; dos Santos, N.A.; Simas, M.L.B.

2014-01-01

356

Generalized theory of resonance scattering (GTRS) using the translational addition theorem for spherical wave functions.  

PubMed

The generalized theory of resonance scattering (GTRS) by an elastic spherical target in acoustics is extended to describe the arbitrary scattering of a finite beam using the addition theorem for the spherical wave functions of the first kind under a translation of the coordinate origin. The advantage of the proposed method over the standard discrete spherical harmonics transform previously used in the GTRS formalism is the computation of the off-axial beam-shape coefficients (BSCs) stemming from a closed-form partial-wave series expansion representing the axial BSCs in spherical coordinates. With this general method, the arbitrary acoustical scattering can be evaluated for any particle shape and size, whether the particle is partially or completely illuminated by the incident beam. Numerical examples for the axial and off-axial resonance scattering from an elastic sphere placed arbitrarily in the field of a finite circular piston transducer with uniform vibration are provided. Moreover, the 3-D resonance directivity patterns illustrate the theory and reveal some properties of the scattering. Numerous applications involving the scattering phenomenon in imaging, particle manipulation, and the characterization of multiphase flows can benefit from the present analysis because all physically realizable beams radiate acoustical waves from finite transducers as opposed to waves of infinite extent. PMID:25389166

Mitri, Farid

2014-11-01

357

Numerical solutions of the quantum Hamilton-Jacobi equation and WKB like representations for one dimensional wave functions  

E-print Network

By means of numerical solutions of the quantum Hamilton Jacobi equation, a general WKB-like representation for one-dimensional wave functions is obtained. This representation is unique in the classically forbidden regions, while in the allowed one, each wave function corresponds to a one parameter family of solutions of the QHJE. The method has been applied to various systems, with different energies and initial conditions. In all investigated cases, the wave functions so obtained accurately reproduce the solutions of the Schr\\"odinger equation, analytically or numerically computed by other ways. Some results for harmonic oscillator and radial Coulomb motion are presented.

Mario Fusco Girard

2014-03-04

358

Fragment-based configuration interaction wave function to calculate environmental effect on excited states in proteins and solutions  

NASA Astrophysics Data System (ADS)

Solvatochromic effect in proteins and solutions was described by a configuration interaction singles (CIS) wave function with fragment-localized molecular orbitals. Coarse-grained analysis indicated that the CI wave function can be described by local excitations and charge-transfer (CT) excitations between the chromophore and the environment. We developed an atomic-orbital direct runcated CIS code and applied the excited states of retinal chromophore in bacteriorhodopsin and MeOH environments, and those of s-trans-acrolein in water. Number of excitation operators was significantly reduced by eliminating the CT excitations between the environmental fragments. The truncated CIS wave functions reproduced the original excitation energies very well.

Hasegawa, Jun-ya

2013-05-01

359

Progress at the interface of wave-function and density-functional theories  

SciTech Connect

The Kohn-Sham (KS) potential of density-functional theory (DFT) emerges as the minimizing effective potential in a variational scheme that does not involve fixing the unknown single-electron density. Using Rayleigh Schroedinger (RS) perturbation theory (PT), we construct ab initio approximations for the energy difference, the minimization of which determines the KS potential directly - thereby bypassing DFT's traditional algorithm to search for the density that minimizes the total energy. From second-order RS PT, we obtain variationally stable energy differences to be minimized, solving the severe problem of variational collapse of orbital-dependent exchange-correlation functionals based on second-order RS PT.

Gidopoulos, Nikitas I. [ISIS, Rutherford Appleton Laboratory, STFC, Didcot, OX11 0QX, Oxon (United Kingdom)

2011-04-15

360

Impact of humidity on surface acoustic wave propagation in vanadium pentoxide xerogel–lithium niobate structure  

NASA Astrophysics Data System (ADS)

The impact of ambient humidity on surface acoustic wave (SAW) propagation in the structure consisting of vanadium pentoxide xerogel (V2O5•nH2O) layer deposited on a piezoelectric lithium niobate (LiNbO3) substrate has been studied. Thin V2O5•nH2O layers were synthesized using sol–gel method and employed as humidity sensing materials. Freshly prepared layer drastically reduced the transmitted SAW signal, which later increased with time reaching saturation after more than 120 h at the level well below the free-surface value. The experimental observations of SAW behaviour were discussed and found related to the variations in resistance and dielectric permittivity of the V2O5•nH2O.

Sereika, Raimundas; Bondarenka, Vladimiras; Rimeika, Romualdas; Sereika, Albertas; ?iplys, Daumantas

2014-11-01

361

The impact of heat, cold, and heat waves on hospital admissions in eight cities in Korea  

NASA Astrophysics Data System (ADS)

Although the impact of temperature on mortality is well documented, relatively fewer studies have evaluated the associations of temperature with morbidity outcomes such as hospital admissions, and most studies were conducted in North America or Europe. We evaluated weather and hospital admissions including specific causes (allergic disease, asthma, selected respiratory disease, and cardiovascular disease) in eight major cities in Korea from 2003 to 2008. We also explored potential effect modification by individual characteristics such as sex and age. We used hierarchical modeling to first estimate city-specific associations between heat, cold, or heat waves and hospitalizations, and then estimated overall effects. Stratified analyses were performed by cause of hospitalization, sex, and age (0-14, 15-64, 65-74, and ?75 years). Cardiovascular hospitalizations were significantly associated with high temperature, whereas hospitalizations for allergic disease, asthma, and selected respiratory disease were significantly associated with low temperature. The overall heat effect for cardiovascular hospitalization was a 4.5 % (95 % confidence interval 0.7, 8.5 %) increase in risk comparing hospitalizations at 25 to 15 °C. For cold effect, the overall increase in risk of hospitalizations comparing 2 with 15 °C was 50.5 (13.7, 99.2 %), 43.6 (8.9, 89.5 %), and 53.6 % (9.8, 114.9 %) for allergic disease, asthma, and selected respiratory disease, respectively. We did not find statistically significant effects of heat waves compared with nonheat wave days. Our results suggest susceptible populations such as women and younger persons. Our findings provide suggestive evidence that both high and low ambient temperatures are associated with the risk of hospital admissions, particularly in women or younger person, in Korea.

Son, Ji-Young; Bell, Michelle L.; Lee, Jong-Tae

2014-01-01

362

The impact of heat, cold, and heat waves on hospital admissions in eight cities in Korea.  

PubMed

Although the impact of temperature on mortality is well documented, relatively fewer studies have evaluated the associations of temperature with morbidity outcomes such as hospital admissions, and most studies were conducted in North America or Europe. We evaluated weather and hospital admissions including specific causes (allergic disease, asthma, selected respiratory disease, and cardiovascular disease) in eight major cities in Korea from 2003 to 2008. We also explored potential effect modification by individual characteristics such as sex and age. We used hierarchical modeling to first estimate city-specific associations between heat, cold, or heat waves and hospitalizations, and then estimated overall effects. Stratified analyses were performed by cause of hospitalization, sex, and age (0-14, 15-64, 65-74, and ?75 years). Cardiovascular hospitalizations were significantly associated with high temperature, whereas hospitalizations for allergic disease, asthma, and selected respiratory disease were significantly associated with low temperature. The overall heat effect for cardiovascular hospitalization was a 4.5 % (95 % confidence interval 0.7, 8.5 %) increase in risk comparing hospitalizations at 25 to 15 °C. For cold effect, the overall increase in risk of hospitalizations comparing 2 with 15 °C was 50.5 (13.7, 99.2 %), 43.6 (8.9, 89.5 %), and 53.6 % (9.8, 114.9 %) for allergic disease, asthma, and selected respiratory disease, respectively. We did not find statistically significant effects of heat waves compared with nonheat wave days. Our results suggest susceptible populations such as women and younger persons. Our findings provide suggestive evidence that both high and low ambient temperatures are associated with the risk of hospital admissions, particularly in women or younger person, in Korea. PMID:24445484

Son, Ji-Young; Bell, Michelle L; Lee, Jong-Tae

2014-11-01

363

Spatial impacts of heat waves in mortality. Evaluating current risks and future threats  

NASA Astrophysics Data System (ADS)

Impacts of heat waves in morbidity and mortality are largely known. Climate Change is expected to increase the climate health impacts in summer while the winter will be probably favored. The health impacts of extreme thermal events are mainly studied at a national or regional level, considering macro or mesoscale thermal features. But it can be assumed that local variations in mortality must exist, associated, in one hand, with local climatic differences, due to features such as land use and urbanization and, in other hand, with vulnerability factors (depending on demographic and socioeconomic characteristics of populations). A model of hazard - vulnerability - risk was developed, to analyze the spatial variations of mortality in extreme thermal events, at the level of city district, in the Lisbon metropolitan area (Portugal). In that model, risk is considered as the product of hazard and vulnerability. Daily mortality data by sex, age and cause of death was supplied by the Health National Authority. The research is yet on-going. In our model, hazard is represented mainly by temperature and air pollution (the influence of other atmospheric variables that affect the human energy balance, such as solar radiation and wind speed should be tested too). Small scale variation of meteorological features, in extreme thermal events, were simulated with a Regional Atmospheric Model (Brazilian Regional Atmospheric Modeling System) and the results were validated and calibrated using observation data from an urban network of termo-higrometers placed in sites with different urban characteristics. Vulnerability is a result on personal sensitivity and exposure. Personal sensitivity is assessed considering individual constitutional and demographic factors as well as socio, cultural and economic variables. Daily mobility determines the population exposure to heat. Since many of these variables are redundant, a set of indicators, including a multiple deprivation index, was used. A first step consists in the modelling of the current relationship between hazard factors, vulnerability and mortality with the aim to explain the variations in mortality, at the city-district scale. In a second step, changes in hazard and vulnerability factors will be simulated. In the changes in meteorological conditions, IPCC and SIAM II scenarios were considered, as well as previsions of urban development and land use changes in the studied area. Demographic and socioeconomic changes should be simulated too. The pretended result with this risk assessment methodology is a prevision of future impacts (intensity and patterns) of the heat waves on mortality.

Andrade, H.; Canario, P.; Nogueira, H.

2009-09-01

364

Impact of wave propagation delay on latency in optical communication systems  

NASA Astrophysics Data System (ADS)

Latency is an important figure to describe performance of transmission systems for particular applications, such as data transfer for earthquake early warning, transaction for financial businesses, interactive services such as online games, etc. Latency consists of delay due to signal processing at nodes and transmitters, and of signal propagation delay due to propagation of electromagnetic waves. The lower limit of the latency in transmission systems using conventional single mode fibers (SMFs) depends on wave propagation speed in the SMFs which is slower than c. Photonic crystal fibers, holly fibers and large core fibers can have low effective refractive indices, and can transfer light faster than in SMFs. In free-space optical systems, signals propagate with the speed c, so that the latency could be smaller than in optical fibers. For example, LEO satellites would transmit data faster than optical submarine cables, when the transmission distance is longer than a few thousand kilometers. This paper will discuss combination of various transmission media to reduce negative impact of the latency, as well as applications of low-latency systems.

Kawanishi, Tetsuya; Kanno, Atsushi; Yoshida, Yuki; Kitayama, Ken-ichi

2012-12-01

365

Cryptic impacts of temperature variability on amphibian immune function.  

PubMed

Ectothermic species living in temperate regions can experience rapid and potentially stressful changes in body temperature driven by abrupt weather changes. Yet, among amphibians, the physiological impacts of short-term temperature variation are largely unknown. Using an ex situ population of Cryptobranchus alleganiensis, an aquatic North American salamander, we tested the hypothesis that naturally occurring periods of temperature variation negatively impact amphibian health, either through direct effects on immune function or by increasing physiological stress. We exposed captive salamanders to repeated cycles of temperature fluctuations recorded in the population's natal stream and evaluated behavioral and physiological responses, including plasma complement activity (i.e. bacteria killing) against Pseudomonas aeruginosa, Escherichia coli and Aeromonas hydrophila. The best-fit model (?AICc=0, wi=0.9992) revealed 70% greater P. aeruginosa killing after exposure to variable temperatures and no evidence of thermal acclimation. The same model predicted 50% increased E. coli killing, but had weaker support (?AICc=1.8, wi=0.2882). In contrast, plasma defenses were ineffective against A. hydrophila, and other health indicators (leukocyte ratios, growth rates and behavioral patterns) were maintained at baseline values. Our data suggest that amphibians can tolerate, and even benefit from, natural patterns of rapid warming/cooling. Specifically, temperature variation can elicit increased activity of the innate immune system. This immune response may be adaptive in an unpredictable environment, and is undetectable by conventional health indicators (and hence considered cryptic). Our findings highlight the need to consider naturalistic patterns of temperature variation when predicting species' susceptibility to climate change. PMID:23948472

Terrell, Kimberly A; Quintero, Richard P; Murray, Suzan; Kleopfer, John D; Murphy, James B; Evans, Matthew J; Nissen, Bradley D; Gratwicke, Brian

2013-11-15

366

Subspace accelerated inexact Newton method for large scale wave functions calculations in Density Functional Theory  

SciTech Connect

We describe an iterative algorithm to solve electronic structure problems in Density Functional Theory. The approach is presented as a Subspace Accelerated Inexact Newton (SAIN) solver for the non-linear Kohn-Sham equations. It is related to a class of iterative algorithms known as RMM-DIIS in the electronic structure community. The method is illustrated with examples of real applications using a finite difference discretization and multigrid preconditioning.

Fattebert, J

2008-07-29

367

Magnetospheric ULF Wave Power as a Function of Solar Wind Variations  

NASA Astrophysics Data System (ADS)

Magnetospheric ULF waves at Pc-5 (mHz) frequencies may have profound effects on relativistic electron fluxes in the outer radiation belts by driving radial diffusion, a process which may either deplete the belts of electrons by allowing electrons to drift outward through the stable trapping boundary, or increasing the overall energy content of the belts through inward radial diffusion and energization of energetic electrons. The energy for most global-scale Pc-5 activity results from the driving action of the solar wind, either through shear interactions at the magnetopause flanks, or directly through pressure or IMF variations embedded in the background solar wind. However, the relationship between ULF power at a given point in the magnetosphere and the driving power of the solar wind is not simple: as a wave propagates through the magnetosphere, partial reflections from Alfven gradients, magnetospheric field line resonances, and global cavity modes may all act to either enhance or suppress wave power at a given frequency and location in space. In this effort we use global MHD simulations of the magnetosphere/solar wind interaction to probe the mapping function of fluctuations in the solar wind into Pc-5 ULF power in the inner magnetosphere and radiation belts. Broadband variations in solarwind conditions are imposed, and the resulting ULF activity in the magnetosphere characterized as a function of frequency and location. This ULF activity may then be used to characterize radial transport rates in the radiation belts in terms of relevant diffusion coefficients. By comparing the ULF power distribution in the magnetosphere during events driven by observed solar wind conditions to those characterized by our broadband mapping, we investigate the feasibility of empirically modeling magnetospheric ULF wave activity as it relates to ULF power in the solar wind.

Elkington, S. R.; Claudepierre, S. G.; Wiltberger, M. J.

2009-12-01

368

Expressions for Neutrino Wave Functions and Transition Probabilities at Three Neutrino Oscillations in Vacuum and Some of Their Applications  

E-print Network

We have considered three neutrino transitions and oscillations in the general case and obtained expressions for neutrino wave functions in three cases: with CP violation, without CP violations and the case when $\

Kh. M. Beshtoev

2005-08-10

369

Erroneous Wave Functions of Ciuchi et al for Collective Modes in Neutron Production on Metallic Hydride Cathodes  

E-print Network

There is a recent comment (Ciuchi et al., 2012) concerning the theory of collective many body effects on the neutron production rates in a chemical battery cathode. Ciuchi et al employ an inverse beta decay expression that contains a two body amplitude. Only one electron and one proton may exist in the Ciuchi et al model initial state wave function. A flaw in their reasoning is that one cannot in reality describe collective many body correlations with only a two particle wave function. One needs very many particles to describe collective effects. In the model wave functions of Ciuchi et al there are no metallic hydrides, there are no cathodes and there are no chemical batteries. Employing a wave function with only one electron and one proton is inadequate for describing collective metallic hydride surface quantum plasma physics in cathodes accurately.

A. Widom; Y. N. Srivastava; L. Larsen

2012-10-17

370

The Impact of Chromospheric Activity on Observed Initial Mass Functions  

E-print Network

Using recently established empirical calibrations for the impact of chromospheric activity on the radii, effective temperatures, and estimated masses of active low-mass stars and brown dwarfs, we reassess the shape of the initial mass function (IMF) across the stellar/substellar boundary in the Upper Sco star-forming region (age 5-10 Myr). We adjust the observed effective temperatures to warmer values using the observed strength of the chromospheric H$\\alpha$ emission, and redetermine the estimated masses of objects using pre--main-sequence evolutionary tracks in the H-R diagram. The effect of the activity-adjusted temperatures is to shift the objects to higher masses by 3-100%. While the slope of the resulting IMF at substellar masses is not strongly changed, the peak of the IMF does shift from ~0.06 to ~0.11 Msun. Moreover, for objects with masses ~0.2 Msun, the ratio of brown dwarfs to stars changes from ~80% to ~33%. These results suggest that activity corrections are essential for studies of the substell...

Stassun, Keivan G; Dupuy, Trent; Kratter, Kaitlin

2014-01-01

371

Explicitly correlated wave functions for atoms and singly charged ions from Li through Sr: Variational and Diffusion Monte Carlo results  

NASA Astrophysics Data System (ADS)

Total energies calculated from explicitly correlated wave functions for the ground state of the atoms Li to Sr and their singly charged anions and cations are obtained. Accurate all electron, non-relativistic Variational and Diffusion Monte Carlo energies are reported. The quality of the results, when comparing with exact estimations and experimental electron affinities and ionization potential is similar for all of the atoms studied. The parameterization of the explicitly correlated wave functions for all of the atomic systems studied is provided.

Buendía, E.; Gálvez, F. J.; Maldonado, P.; Sarsa, A.

2014-11-01

372

Direct Measurement of the Pion Valence-Quark Momentum Distribution, the Pion Light-Cone Wave Function Squared  

Microsoft Academic Search

We present the first direct measurements of the pion valence-quark momentum distribution which is related to the square of the pion light-cone wave function. The measurements were carried out using data on diffractive dissociation of 500 GeV\\/c pi- into dijets from a platinum target at Fermilab experiment E791. The results show that the \\\\|qq¯> light-cone asymptotic wave function describes the

E. M. Aitala; S. Amato; J. C. Anjos; J. A. Appel; D. Ashery; S. Banerjee; I. Bediaga; G. Blaylock; S. B. Bracker; R. A. Burnstein; T. Carter; H. S. Carvalho; N. K. Copty; L. M. Cremaldi; C. Darling; K. Denisenko; S. Deval; A. Fernandez; G. F. Fox; P. Gagnon; S. Gerzon; C. Gobel; K. Gounder; A. M. Halling; G. Herrera; G. Hurvits; C. James; P. A. Kasper; S. Kwan; D. C. Langs; J. Lichtenstadt; B. Lundberg; S. Maytal-Beck; B. Meadows; J. R. de Mello Neto; D. Mihalcea; R. H. Milburn; J. M. de Miranda; A. Napier; A. Nguyen; A. B. D'Oliveira; K. O'Shaughnessy; K. C. Peng; L. P. Perera; M. V. Purohit; B. Quinn; S. Radeztsky; A. Rafatian; N. W. Reay; J. J. Reidy; A. C. Dos Reis; H. A. Rubin; D. A. Sanders; A. K. Santha; A. F. Santoro; A. J. Schwartz; M. D. Sokoloff; R. A. Sidwell; A. J. Slaughter; J. Solano; N. R. Stanton; R. J. Stefanski; K. Stenson; D. J. Summers; S. Takach; K. Thorne; A. K. Tripathi; S. Watanabe; R. Weiss-Babai; J. Wiener; N. Witchey; E. Wolin; S. M. Yang; D. Yi; S. Yoshida; R. Zaliznyak; C. Zhang

2001-01-01

373

Characterization of a Setup to test the Impact of High-Amplitude Pressure Waves on Living Cells  

PubMed Central

The impact of pressure waves on cells may provide several possible applications in biology and medicine including the direct killing of tumors, drug delivery or gene transfection. In this study we characterize the physical properties of mechanical pressure waves generated by a nanosecond laser pulse in a setup with well-defined cell culture conditions. To systematically characterize the system on the relevant length and time scales (micrometers and nanoseconds) we use photon Doppler velocimetry (PDV) and obtain velocity profiles of the cell culture vessel at the passage of the pressure wave. These profiles serve as input for numerical pressure wave simulations that help to further quantify the pressure conditions on the cellular length scale. On the biological level we demonstrate killing of glioblastoma cells and quantify experimentally the pressure threshold for cell destruction. PMID:24458018

Schmidt, Mischa; Kahlert, Ulf; Wessolleck, Johanna; Maciaczyk, Donata; Merkt, Benjamin; Maciaczyk, Jaroslaw; Osterholz, Jens; Nikkhah, Guido; Steinhauser, Martin O.

2014-01-01

374

Characterization of a setup to test the impact of high-amplitude pressure waves on living cells.  

PubMed

The impact of pressure waves on cells may provide several possible applications in biology and medicine including the direct killing of tumors, drug delivery or gene transfection. In this study we characterize the physical properties of mechanical pressure waves generated by a nanosecond laser pulse in a setup with well-defined cell culture conditions. To systematically characterize the system on the relevant length and time scales (micrometers and nanoseconds) we use photon Doppler velocimetry (PDV) and obtain velocity profiles of the cell culture vessel at the passage of the pressure wave. These profiles serve as input for numerical pressure wave simulations that help to further quantify the pressure conditions on the cellular length scale. On the biological level we demonstrate killing of glioblastoma cells and quantify experimentally the pressure threshold for cell destruction. PMID:24458018

Schmidt, Mischa; Kahlert, Ulf; Wessolleck, Johanna; Maciaczyk, Donata; Merkt, Benjamin; Maciaczyk, Jaroslaw; Osterholz, Jens; Nikkhah, Guido; Steinhauser, Martin O

2014-01-01

375

Extracting elements of molecular structure from the all-particle wave function  

SciTech Connect

Structural information is extracted from the all-particle (non-Born-Oppenheimer) wave function by calculating radial and angular densities derived from n-particle densities. As a result, one- and two-dimensional motifs of classical molecular structure can be recognized in quantum mechanics. Numerical examples are presented for three- (H{sup -}, Ps{sup -}, H{sub 2}{sup +}), four- (Ps{sub 2}, H{sub 2}), and five-particle (H{sub 2}D{sup +}) systems.

Matyus, Edit; Reiher, Markus [Laboratory of Physical Chemistry, ETH Zuerich, Wolfgang-Pauli-Str. 10, CH-8093 Zuerich (Switzerland); Hutter, Juerg [Institute of Physical Chemistry, University of Zuerich, Winterthurerstrasse 190, CH-8057 Zuerich (Switzerland); Mueller-Herold, Ulrich [Institute of Biogeochemistry and Pollutant Dynamics, ETH Zuerich, Universitaetstrasse 16, CH-8092 Zuerich (Switzerland)

2011-11-28

376

Resonance fluorescence near a photonic band edge: Dressed-state Monte Carlo wave-function approach  

NASA Astrophysics Data System (ADS)

We introduce a dressed-state Monte Carlo wave-function technique to describe resonance fluorescence in a broad class of non-Markovian reservoirs with strong atom-reservoir interaction. The method recaptures photon localization effects which are beyond the Born and Markovian approximations, and describes the influence of the driving field on the atom-reservoir interaction. Using this approach, we predict a number of fundamentally new features in resonance fluorescence near the edge of a photonic band gap. In particular, the atomic population exhibits inversion for moderate applied field intensity. For a low external field intensity, the atomic system retains a long-time memory of its initial state.

Quang, Tran; John, Sajeev

1997-11-01

377

Transport in open spin chains: A Monte Carlo wave-function approach  

E-print Network

We investigate energy transport in several two-level atom or spin-1/2 models by a direct coupling to heat baths of different temperatures. The analysis is carried out on the basis of a recently derived quantum master equation which describes the nonequilibrium properties of internally weakly coupled systems appropriately. For the computation of the stationary state of the dynamical equations, we employ a Monte Carlo wave-function approach. The analysis directly indicates normal diffusive or ballistic transport in finite models and hints toward an extrapolation of the transport behavior of infinite models.

Mathias Michel; Ortwin Hess; Hannu Wichterich; Jochen Gemmer

2008-03-07

378

Moments distributions of the mesons wave functions from QCD spectral sum rules  

NASA Astrophysics Data System (ADS)

We test the consistency and the accuracy of previous “fitted values” of the moments distributions of the mesons wave functions by combining constraints from finite energy sum rules (FESR) and Laplace transform sum rules (LSR) satisfying the onset of QCD continuum and LSR variable stability criteria. Analyzing the sensitivity of the results on the values of the QCD condensates, we confirm and improve Chernyak-Zhitnitsky (CZ) estimates of the ? meson moments but provide new results for the other mesons (?, A 1 and B (db)). Most of the sets of the parameters estimated by CZ do not fulfill the above mentioned self-consistency checks.

Narison, Stephan

1989-06-01

379

Nonlocality of quark condensates and the wave function of the pion in QCD  

Microsoft Academic Search

We propose a generalization of the QCD sum rule method for determining the pion wave function Φ{sub Ï} ({ital x}) by introducing nonlocal quark condensates, {l angle}{ital {bar q}}(0){ital q}({ital z}){r angle}{equivalent to}{ital M}({ital z}²), {l angle}{ital {bar q}}(0){ital {cflx n}{cflx A}}{sub μ}({ital y}){ital q}({ital z}){r angle}={ital M}{sub μ} ({ital y},{ital z}), etc. We show that the QCD sum rules

S. V. Mikhailov; A. V. Radyushkin

1989-01-01

380

Impact of shear rate modulation on vascular function in humans.  

PubMed

Shear stress is an important stimulus to arterial adaptation in response to exercise and training in humans. We recently observed significant reverse arterial flow and shear during exercise and different antegrade/retrograde patterns of shear and flow in response to different types of exercise. The purpose of this study was to simultaneously examine flow-mediated dilation, a largely NO-mediated vasodilator response, in both brachial arteries of healthy young men before and after 30-minute interventions consisting of bilateral forearm heating, recumbent leg cycling, and bilateral handgrip exercise. During each intervention, a cuff inflated to 60 mm Hg was placed on 1 arm to unilaterally manipulate the shear rate stimulus. In the noncuffed arm, antegrade flow and shear increased similarly in response to each intervention (ANOVA; P<0.001, no interaction between interventions; P=0.71). Baseline flow-mediated dilation (4.6%, 6.9%, and 6.7%) increased similarly in response to heating, handgrip, and cycling (8.1%, 10.4%, and 8.9%, ANOVA; P<0.001, no interaction; P=0.89). In contrast, cuffed arm antegrade shear rate was lower than in the noncuffed arm for all of the conditions (P<0.05), and the increase in flow-mediated dilation was abolished in this arm (4.7%, 6.7%, and 6.1%; 2-way ANOVA: all conditions interacted P<0.05). These results suggest that differences in the magnitude of antegrade shear rate transduce differences in endothelial vasodilator function in humans, a finding that may have relevance for the impact of different exercise interventions on vascular adaptation in humans. PMID:19546374

Tinken, Toni M; Thijssen, Dick H J; Hopkins, Nicola; Black, Mark A; Dawson, Ellen A; Minson, Christopher T; Newcomer, Sean C; Laughlin, M Harold; Cable, N Timothy; Green, Daniel J

2009-08-01

381

Two-particle wave function as an integral operator and the random field approach to quantum correlations  

NASA Astrophysics Data System (ADS)

We propose a new interpretation of the wave function ? (x, y) of a two-particle quantum system, interpreting it not as an element of the functional space L 2 of square-integrable functions, i.e., as a vector, but as the kernel of an integral (Hilbert-Schmidt) operator. The first part of the paper is devoted to expressing quantum averages including the correlations in two-particle systems using the wave-function operator. This is a new mathematical representation in the framework of conventional quantum mechanics. But the new interpretation of the wave function not only generates a new mathematical formalism for quantum mechanics but also allows going beyond quantum mechanics, i.e., representing quantum correlations (including those in entangled systems) as correlations of (Gaussian) random fields.

Khrennikov, A. Yu.

2010-09-01

382

Indexes to anticipate negative impacts of heat waves in urban Mediterranean environments  

NASA Astrophysics Data System (ADS)

This study intention is to understand what might be the better indexes to anticipate health deterioration during temperature extreme events in a urban Mediterranean environment like Porto. To do this we look to the effects of the July 2006 Heat Wave using the Heat Index on the Mortality (All Causes) and Morbidity (All Causes, Respiratory and Circulatory diseases) in general, and in people over 74 years and by Gender, in Porto. The Poisson Generalized Additive Regression model was used in order to estimate the impact of Apparent Temperature (Heat Index) and Daily Mortality and Morbidity during the July 2006 Heat Wave. Daily Mortality, Morbidity and Heat Index was correlated with lags of Apparent Temperature up to 7 days using Pearson correlation. For a 1°C increase in mean Apparent Temperature we observed a 2.7% (95%CI:1.7-3.6%) increase in Mortality (for All Causes), 1.7% (95%CI:0.6-2.9%) in Respiratory Morbidity, 2,2% (95%CI:0.4-4.1%) in Women Respiratory Morbidity, 5,4% (95%CI:1.1-6.6%) in Chronic Obstructive Pulmonary Morbidity and 7,5% (95%CI:1.3-14.1%) in Women Chronic Obstructive Pulmonary Morbidity, for the entire population. For people ? 75 years, our work showed a 3,3% increase (95%CI:1.7-5.0%) in Respiratory Morbidity, 2,7% (95%CI:0.4-5.1%) in Men Respiratory Morbidity, 3,9% (95%CI:1.6-6.3%) in Women Respiratory Morbidity, 7.0% (95%CI:1.1-13.2%) in Chronic Obstructive Pulmonary Disease and 9.0% (95%CI:0.3-18.5%) in Women Chronic Obstructive Pulmonary Disease. We conclude that the use of Heat Index in a Mediterranean Tempered Climate enabled the identification of the effects of the July 2006 Heat Wave in Mortality due to All Causes and in Respiratory Morbidity of the General Population, as well as in Respiratory Morbidity of individuals with more than 74 years of age.

Monteiro, A. M.; Carvalho, C. V.; Velho, S. V.; Sousa, C. S.

2012-04-01

383

Equality Impact Assessment Summary Name of policy, function or service  

E-print Network

for Wales - WAG Equality Impact Assessment. In addition to the evidence collated in that exercise. New this exercise has been incorporated in the policy position. Comments received were considered and where require more focused EqIAs to consider impacts and give opportunities to promote diversity. Local

384

Study on the propagation of coupling shock waves with phase transition under combined tension-torsion impact loading  

NASA Astrophysics Data System (ADS)

Phase transition can strongly change the stress wave propagation features. In this paper, the characteristic wave propagation under combined tension and torsion impact loading was studied with a simplified constitutive model of phase transition considering both pressure and shear stress. The results showed that for loading from the austenitic phase to the mixed phase, the wave propagation was similar to that in the elasto-plastic materials. However, for an instantaneous loading from the austenitic phase or mixed phase directly to the martensitic phase, a coupling shock wave (CSHW) with phase transition was predicted due to the second phase strengthening effect, which has barely been studied before. Through analysis of the constitutive equations with phase transition and the discontinuity conditions of shock waves, the control equations of the generalized Hugoniot curve was obtained and the CSHW problem with phase transition was solved analytically. An independent numerical simulation of step loading along a NiTi thin walled tube suffering a combined tension-torsion impact loading was given to prove the existence of CSHW. The simulation discloses the formation mechanism of CSHW and the adjusting process of the stress state ahead of CSHW, which reflects the intrinsic characteristic of materials with strong nonlinear constitutive behavior.

Wang, Bo; Tang, ZhiPing

2014-10-01

385

Magnetostatic Green's functions for the description of spin waves in finite rectangular magnetic dots and stripes  

NASA Astrophysics Data System (ADS)

We present derivation of the magnetostatic Green's functions used in calculations of spin-wave spectra of finite-size non-ellipsoidal (rectangular) magnetic elements. The elements (dots) are assumed to be single domain particles having uniform static magnetization. We consider the case of flat dots, when the in-plane dot size is much larger than the dot height (film thickness), and assume the uniform distribution of the variable magnetization along the dot height. The limiting cases of magnetic waveguides with rectangular cross-section and thin magnetic stripes are also considered. The developed method of tensorial Green's functions is used to solve the Maxwell equations in the magnetostatic limit, and to represent the Landau-Lifshitz equation of motion for the magnetization of a magnetic element in a closed integro-differential form.

Guslienko, Konstantin Y.; Slavin, Andrei N.

2011-10-01

386

BCS wave-function approach to the BEC-BCS crossover of exciton-polariton condensates.  

PubMed

The crossover between low and high density regimes of exciton-polariton condensates is examined using a BCS wave-function approach. Our approach is an extension of the BEC-BCS crossover theory for excitons, but includes a cavity photon field. The approach can describe both the low density limit, where the system can be described as a Bose-Einstein condensate (BEC) of exciton-polaritons, and the high density limit, where the system enters a photon-dominated regime. In contrast to the exciton BEC-BCS crossover where the system approaches an electron-hole plasma, the polariton high density limit has strongly correlated electron-hole pairs. At intermediate densities, there is a regime with BCS-like properties, with a peak at nonzero momentum of the singlet pair function. We calculate the expected photoluminescence and give several experimental signatures of the crossover. PMID:21231119

Byrnes, Tim; Horikiri, Tomoyuki; Ishida, Natsuko; Yamamoto, Yoshihisa

2010-10-29

387

Crustal Structure of Iraq from Receiver Functions and Surface Wave Dispersion  

SciTech Connect

We report the crustal structure of Iraq, located in the northeastern Arabian plate, estimated by joint inversion of P-wave receiver functions and surface wave group velocity dispersion. Receiver functions were computed from teleseismic recordings at two temporary broadband seismic stations in Mosul (MSL) and Baghdad (BHD), separated by approximately 360 km. Group velocity dispersion curves at the sites were derived from continental-scale tomography of Pasyanos (2006). The inversion results show that the crustal thicknesses are 39 km at MSL and 43 km at BHD. Both sites reveal low velocity surface layers consistent with sedimentary thickness of about 3 km at station MSL and 7 km at BHD, agreeing well with the existing models. Ignoring the sediments, the crustal velocities and thicknesses are remarkably similar between the two stations, suggesting that the crustal structure of the proto-Arabian Platform in northern Iraq was uniform before subsidence and deposition of the sediments in the Cenozoic. Deeper low velocity sediments at BHD are expected to result in higher ground motions for earthquakes.

Gok, R; Mahdi, H; Al-Shukri, H; Rodgers, A J

2006-08-31

388

Velocity and attenuation of seismic waves in random media: A spectral function approach  

NASA Astrophysics Data System (ADS)

This contribution investigates the scattering of scalar and elastic waves in two-phase materials and single-mineral-cubic, hexagonal, orthorhombic-polycrystalline aggregates with randomly oriented grains. Based on the Dyson equation for the mean field, explicit expressions for the imaginary part of Green's function in the frequency-wavenumber domain (?,p), also known as the spectral function, are derived. This approach allows the identification of propagating modes with their relative contribution, and the computation of both attenuation and phase velocity for each mode. The results should be valid from the Rayleigh (low-frequency) to the geometrical optics (high-frequency) regime. Applications of the proposed theory to the structure of the inner core of the Earth will be presented. In particular, it will be shown that our scattering theory can explain the striking correlation between velocity and attenuation and the associated hemispherical variations revealed by PKP waves propagating through the inner core of the Earth. The implications for inner core dynamics will be summarized.

Margerin, Ludovic; Calvet, Marie; Monnereau, Marc; Souriau, Annie

2013-04-01

389

Nonlocal condensates and QCD sum rules for the pion wave function  

NASA Astrophysics Data System (ADS)

The QCD-sum-rule calculation of the pion wave function by Chernyak and Zhitnitsky (CZ) implicitly assumes that the correlation length of vacuum fluctuations is large compared to the typical hadronic scale ~1/m?, so that one can substitute the original nonlocal objects such as by constant -type values. We outline a formalism enabling one to work directly with the nonlocal condensates, and construct a modified sum rule for the moments of the pion wave function. The results are rather sensitive to the value of the parameter ?2q=/ specifying the average virtuality of the vacuum quarks. Varying it from the most popular value ?2q=0.4 GeV2 up to the value ?2q=1.2 GeV2 suggested by the instanton-liquid model, we obtain =0.25-0.20, to be compared to the CZ value =0.43 obtained with ?2q=0.

Mikhailov, S. V.; Radyushkin, A. V.

1992-03-01

390

Does consciousness really collapse the wave function? A possible objective biophysical resolution of the measurement problem  

E-print Network

An analysis has been performed of the theories and postulates advanced by von Neumann, London and Bauer, and Wigner, concerning the role that consciousness might play in the collapse of the wave function, which has become known as the measurement problem. This reveals that an error may have been made by them in the area of biology and its interface with quantum mechanics, when they called for the reduction of any superposition states in the brain through the mind or consciousness. Many years later Wigner changed his mind to reflect a simpler and more realistic objective position, expanded upon by Shimony, which appears to offer a way to resolve this issue. The argument is therefore made that the wave function of any superposed photon state or states is always objectively changed within the complex architecture of the eye in a continuous linear process initially for most of the superposed photons, followed by a discontinuous nonlinear collapse process later for any remaining superposed photons, thereby guaranteeing that only final, measured information is presented to the brain, mind or consciousness. An experiment to be conducted in the near future may enable us to simultaneously resolve the measurement problem and also determine if the linear nature of quantum mechanics is violated by the perceptual process.

Fred H. Thaheld

2005-09-06

391

Accurate explicitly correlated wave functions for two electrons in a square  

NASA Astrophysics Data System (ADS)

An explicitly correlated linear-r12 variational method is developed for a system of two electrons confined to a two-dimensional square well with infinite walls. The wave function is written as an expansion in products of non-negative integer powers of the relative and center-of-mass electronic coordinates and powers of r12 restricted to 0 and 1. This form indirectly includes higher powers of the interelectronic distance and exhibits a much faster convergence than a similar expansion without r12-dependent terms. The method is implemented using high-precision floating-point arithmetic. Ground-state total energies are reported with at least 12 accurate significant figures for squares with sides from 1 to 50 bohrs. The method can be used ``as is'' for excited states and for two-dimensional rectangular wells. We also show that wave functions for two electrons in a square and in a rectangle have a higher symmetry than can be accounted for by the point group of the system.

Ryabinkin, Ilya G.; Staroverov, Viktor N.

2011-07-01

392

Pixel level optical-transfer-function design based on the surface-wave-interferometry aperture  

PubMed Central

The design of optical transfer function (OTF) is of significant importance for optical information processing in various imaging and vision systems. Typically, OTF design relies on sophisticated bulk optical arrangement in the light path of the optical systems. In this letter, we demonstrate a surface-wave-interferometry aperture (SWIA) that can be directly incorporated onto optical sensors to accomplish OTF design on the pixel level. The whole aperture design is based on the bull’s eye structure. It composes of a central hole (diameter of 300 nm) and periodic groove (period of 560 nm) on a 340 nm thick gold layer. We show, with both simulation and experiment, that different types of optical transfer functions (notch, highpass and lowpass filter) can be achieved by manipulating the interference between the direct transmission of the central hole and the surface wave (SW) component induced from the periodic groove. Pixel level OTF design provides a low-cost, ultra robust, highly compact method for numerous applications such as optofluidic microscopy, wavefront detection, darkfield imaging, and computational photography. PMID:20721038

Zheng, Guoan; Wang, Yingmin; Yang, Changhuei

2010-01-01

393

On- and off-resonance radiation-atom-coupling matrix elements involving extended atomic wave functions  

NASA Astrophysics Data System (ADS)

In continuation of our earlier works, we present results concerning the computation of matrix elements of the multipolar Hamiltonian (MPH) between extended wave functions that are obtained numerically. The choice of the MPH is discussed in connection with the broader issue of the form of radiation-atom (or -molecule) interaction that is appropriate for the systematic solution of various problems of matter-radiation interaction. We derive analytic formulas, in terms of the sine-integral function and spherical Bessel functions of various orders, for the cumulative radial integrals that were obtained and calculated by Komninos, Mercouris, and Nicolaides [Phys. Rev. A 71, 023410 (2005), 10.1103/PhysRevA.71.023410]. This development allows the much faster and more accurate computation of such matrix elements, a fact that enhances the efficiency with which the time-dependent Schrödinger equation is solved nonperturbatively, in the framework of the state-specific expansion approach. The formulas are applicable to the general case where a pair of orbitals with angular parts |?1,m1> and |?2,m2> are coupled radiatively. As a test case, we calculate the matrix elements of the electric field and of the paramagnetic operators for on- and off-resonance transitions, between hydrogenic circular states of high angular momentum, whose quantum numbers are chosen so as to satisfy electric dipole and electric quadrupole selection rules. Because of the nature of their wave function (they are nodeless and the large centrifugal barrier keeps their overwhelming part at large distances from the nucleus), the validity of the electric dipole approximation in various applications where the off-resonance couplings must be considered becomes precarious. For example, for the transition from the circular state with n = 20 to that with n = 21, for which ?400 a.u., the dipole approximation starts to fail already at XUV wavelengths (? <125nm).

Komninos, Yannis; Mercouris, Theodoros; Nicolaides, Cleanthes A.

2014-01-01

394

On the large interelectronic distance behavior of the correlation factor for explicitly correlated wave functions  

NASA Astrophysics Data System (ADS)

In currently most popular explicitly correlated electronic structure theories, the dependence of the wave function on the interelectronic distance rij is built via the correlation factor f (rij). While the short-distance behavior of this factor is well understood, little is known about the form of f (rij) at large rij. In this work, we investigate the optimal form of f (r12) on the example of the helium atom and helium-like ions and several well-motivated models of the wave function. Using the Rayleigh-Ritz variational principle, we derive a differential equation for f (r12) and solve it using numerical propagation or analytic asymptotic expansion techniques. We found that for every model under consideration, f (r12) behaves at large rij as r12? eBr12 and obtained simple analytic expressions for the system dependent values of ? and B. For the ground state of the helium-like ions, the value of B is positive, so that f (r12) diverges as r12 tends to infinity. The numerical propagation confirms this result. When the Hartree-Fock orbitals, multiplied by the correlation factor, are expanded in terms of Slater functions rne-?r, n = 0,...,N, the numerical propagation reveals a minimum in f (r12) with depth increasing with N. For the lowest triplet state, B is negative. Employing our analytical findings, we propose a new ``range-separated'' form of the correlation factor with the short- and long-range r12 regimes approximated by appropriate asymptotic formulas connected by a switching function. Exemplary calculations show that this new form of f (r12) performs somewhat better than the correlation factors used thus far in the standard R12 or F12 theories.

Lesiuk, Micha?; Jeziorski, Bogumi?; Moszynski, Robert

2013-10-01

395

Relativistic parametrization of the self-consistent-charge density-functional tight-binding method. 1. Atomic wave functions and energies.  

PubMed

A detailed treatment of a confined relativistic atom, needed as an initial step for the parametrization of the self-consistent-charge density-functional tight-binding method, is presented and discussed. The required one-component quantities, i.e., orbital energies, orbital wave functions, and Hubbard parameters, are obtained by weighted averaging of the corresponding numbers determined for the atomic spinors. The wave function and density confinement is achieved by introducing the Woods-Saxon potential in the atomic four-component Dirac-Kohn-Sham problem. The effect of the additional confining potential on energy eigenvalues and the shape of atomic wave functions and densities is discussed and numerical examples are presented for the valence spinors of carbon, germanium, and lead. PMID:17567112

Witek, Henryk A; Köhler, Christof; Frauenheim, Thomas; Morokuma, Keiji; Elstner, Marcus

2007-07-01

396

Impact of functional dyspepsia on quality of life  

Microsoft Academic Search

Little information on functional status and well-being is available in patients with functional gastrointestinal disease. We aimed to evaluate whether quality of life is poorer in patients with functional dyspepsia. A consecutive sample of 73 patients with functional dyspepsia completed a validated questionnaire prior to endoscopy. Organic disease controls comprised 658 outpatients attending endoscopy. Quality of life was measured using

Nicholas J. Talley; Amy L. Weaver; Alan R. Zinsmeister

1995-01-01

397

Functional impact of emotions on athletic performance: Comparing the IZOF model and the directional perception approach  

Microsoft Academic Search

The aim of this study was to examine the impact of emotions on athletic performance within the frameworks of the Individual Zones of Optimal Functioning (IZOF) model and the directional perception approach. Intensity, functional impact, and hedonic tone of trait and state anxiety, self-confidence, idiosyncratic emotions, and bodily symptoms were assessed in high-level Italian swimmers and track and field athletes

Claudio Robazza; Melinda Pellizzari; Maurizio Bertollo; Yuri L. Hanin

2008-01-01

398

Excitation functions for positively charged fragments produced by electron impact on thymine  

NASA Astrophysics Data System (ADS)

Fragmentation of thymine in the gas phase is studied using low-energy electron impact. Positive ions have been detected using a reflectron time-of-flight mass spectrometer. Mass spectra have been measured as a function of electron impact from the ionization threshold to 400 eV, and excitation functions of most of the positively charged fragments have been extracted.

Mahon, F.; Finnegan, S.; van der Burgt, P. J. M.

2014-04-01

399

Excitation functions for positively charged fragments produced by electron impact on adenine  

NASA Astrophysics Data System (ADS)

Fragmentation of adenine in the gas phase is studied using low-energy electron impact. Positive ions have been detected using a reflectron time-of-flight mass spectrometer. Mass spectra have been measured as a function of electron impact from the ionization threshold to 400 eV, and excitation functions of most of the positively charged fragments have been extracted.

Finnegan, S.; Mahon, F.; Eden, S.; van der Burgt, P. J. M.

2014-04-01

400

Study of Kinematics of Extreme Waves Impacting Offshore and Coastal Structures by Non Intrusive Measurement Techniques  

E-print Network

Extreme wave flows associated with a large scale wave breaking during interactions with marine structures or complex coastal geography of is one of the major concerns in a design of coastal and ocean structures. In order to properly understand...

Song, Youn Kyung

2013-11-07

401

Impact of localized inhomogeneity on the surface-wave velocity and bulk-wave reflection in solids.  

PubMed

The effect of a weak surface, near-surface and interfacial inhomogeneity on the frequency dependence of the surface wave velocity and of the SH (shear horizontal) wave reflectivity in isotropic elastic media is studied analytically and numerically. The inhomogeneity is modeled as an infinite planar layer with continuously varying properties. Weak inhomogeneity may markedly affect the dispersion of the Rayleigh velocity and especially of the reflectivity. It is demonstrated how this effect, particularly pronounced at high frequency, depends on the extent of inhomogeneity. The material data for damaged and ideal concrete and several simple examples of inhomogeneity profiles are utilized for the numerical calculations based on the Peano expansion. The use of explicit low- and high-frequency approximations is also exemplified. Among these, simple WKB asymptotics are shown to be particularly helpful for the Rayleigh velocity in the case of a prominent inhomogeneity attached to the surface and for the reflection on weak interfaces. PMID:17064750

Baron, C; Shuvalov, A L; Poncelet, O

2007-03-01

402

An estimate of the global impact of multiple scattering by clouds on outgoing long-wave radiation  

NASA Astrophysics Data System (ADS)

Although the potential importance of scattering of long-wave radiation by clouds has been recognised, most studies have concentrated on the impact of high clouds and few estimates of the global impact of scattering have been presented. This study shows that scattering in low clouds has a significant impact on outgoing long-wave radiation (OLR) in regions of marine stratocumulus (-3.5 W m-2 for overcast conditions) where the column water vapour is relatively low. This corresponds to an enhancement of the greenhouse effect of such clouds by 10%. The near-global impact of scattering on OLR is estimated to be -3.0 W m-2, with low clouds contributing -0.9 W m-2, mid-level cloud -0.7 W m-2 and high clouds -1.4 W m-2. Although this effect appears small compared to the global mean OLR of 240 W m-2, it indicates that neglect of scattering will lead to an error in cloud long-wave forcing of about 10% and an error in net cloud forcing of about 20%.

Costa, S. M. S.; Shine, K. P.

2006-04-01

403

PICASSO: Lithosphere Structure in the Western Mediterranean from Ps Receiver Functions and Rayleigh Wave Tomography  

NASA Astrophysics Data System (ADS)

The western Mediterranean is a diffuse plate boundary separating the African and Eurasian plates. Cenozoic deformation is centered on the Gibraltar arc and Alboran Sea, and occupies a wide area from the southern Iberian Massif in Spain to the Atlas Mountains in Morocco. We present a model of the lithospheric structure of this region derived from Rayleigh wave tomography and Ps receiver functions, using data from the PICASSO (Program to Investigate Convective Alboran Sea System Overturn) linear broadband array of ~100 seismographs. This array is deployed from central Spain to the Morocco-Algerian border. We complement these data with some of that recorded by IberArray, an areal broadband array, operated by the Spanish seismological community, covering the same region with a uniform 50 km x 50 km grid of stations. Rayleigh phase velocities have been measured from 20-167s period using the two-plane-wave method to remove complications due to multi-pathing, and finite-frequency kernels to improve lateral resolution. The phase velocities were inverted for 1D structure on a 0.25 by 0.25 degree grid. Ps receiver functions at 1Hz and 2Hz were calculated for the same area using water-level and time-domain iterative deconvolution, and were then CCP stacked. The Rayleigh wave shear velocity model, jointly interpreted with the discontinuity structure from the CCP stack, shows the first-order lithospheric structure, and the lithosphere-asthenosphere boundary (LAB). From north to south along the PICASSO profile: The lithosphere is ~120 km thick beneath the Iberian Massif, where it has the highest shear velocity, 4.45 km/s. To the south the lithosphere thins dramatically beneath the Betic Mountains to ~85 km, and then varies in thickness and decreases in velocity beneath the Alboran Sea and Gibraltar Arc. The thinnest lithosphere, ~60 km, is observed beneath the Rif mountains and Middle Atlas, with a low velocity feature (4.2 km/s) at ~60 km depth beneath a site of Late Cenozoic basaltic volcanism. Further south the lithosphere thickens again beneath the High Atlas and the Sahara Platform (~100 km) where the upper mantle shear velocity increases (~4.40 km/s). The CCP images show surprisingly complicated crustal and upper mantle structures under the Betics. The combined images show that lithospheric thickness in the plate boundary zone varies by more than a factor of 2 and that upper mantle shear wave velocities are reduced by ~6% relative to the Iberian Massive and Sahara Platform.

Palomeras, I.; Thurner, S.; Levander, A.; Humphreys, E.; Miller, M. S.; Carbonell, R.; Gallart, J.

2012-04-01

404

Seismic waves generated by aircraft impacts and building collapses at World Trade Center, New York City  

NASA Astrophysics Data System (ADS)

Seismologists sometimes do their work of data acquisition and analysis against a tragic background. Usually, the context is fieldwork far from home, in an area subjected to the natural but sometimes devastating effects of an earthquake. But in the present case, we are in our own New York City area; that is, the Lamont-Doherty Earth Observatory of Columbia University, in Palisades, N.Y; and the context is inhuman actions against people and the fabric of our society.As the appalling events of September 11 unfolded, we found that we had recorded numerous seismic signals from two plane impacts and building collapses of the two World Trade Center (WTC) towers, often at times different than those being reported elsewhere. Collapses of the two WTC towers generated large seismic waves, observed in five states and up to 428 km away The north tower collapse was the largest seismic source and had local magnitude ML 2.3. From this, we infer that ground shaking of the WTC towers was not a major contributor to the collapse or damage to surrounding buildings. But unfortunately, we also conclude that from the distance at which our own detections were made (the nearest station is 34 km away at Palisades) it is not possible to infer (with detail sufficient to meet the demands of civil engineers in an emergency situation) just what the near-in ground motions must have been.

Kim, Won-Young; Sykes, L. R.; Armitage, J. H.; Xie, J. K.; Jacob, K. H.; Richards, P. G.; West, M.; Waldhauser, F.; Armbruster, J.; Seeber, L.; Du, W. X.; Lerner-Lam, A.

405

A theory on the distribution function of backscatter radar cross section from ocean waves of individual wavelength  

Microsoft Academic Search

A new and simple method of interpreting the “distribution” of the backscatter radar cross section (RCS) from ocean waves of individual wavelength is presented. Using the Kirchhoff scattering (Physical Optics) theory, the “cumulative” RCS from the ambient waveheight spectrum is first computed as a function of the wavenumber. Differentiating this cumulative RCS yields the distribution function of the RCS from

Kazuo Ouchi

2000-01-01

406

Climate extremes in urban area and their impact on human health: the summer heat waves  

NASA Astrophysics Data System (ADS)

In the period 1951-2012 the average global land and ocean temperature has increased by approximately 0.72°C [0.49-0.89] when described by a linear trend, and is projected to rapidly increase. Each of the past three decades has been warmer than all the previous decades, with the decade of the 2000's as the warmest, and, since 1880, nine of the ten warmest years are in the 21st century, the only exception being 1998, which was warmed by the strongest El Niño event of the past century. In parallel an increase in the frequency and intensity of extremely hot days is detected with differences at different scales, which represent an health risk specially in largely populated areas as documented for several regions in the world including the Euro-Mediterranean region. If it is still under discussion if heat wave episodes are a direct result of the warming of the lower troposphere, or if, more likely, they are a regional climate event, however heat episodes have been studied in order to define their correlation with large scale atmospheric patterns and with changes in the regional circulation. Whatever the causes and the spatio-temporal extension of the episodes, epidemiological studies show that these conditions pose increasing health risks inducing heat-related diseases including hyperthermia and heat stress, cardiovascular and respiratory illnesses in susceptible individuals with a significant increase in morbidity and mortality especially in densely populated urban areas. In several Mediterranean cities peaks of mortality associated with extremely high temperature (with simultaneous high humidity levels) have been documented showing that, in some cases, a large increase in daily mortality has been reached compared to the average for the period. The number of fatalities during the summer 2003 heat wave in Europe was estimated to largely exceed the average value of some between 22000 and 50000 cases. In the same summer it was also unusually hot across much of Asia, and Shanghai, which is particularly prone to heat waves, recorded the hottest summer in over 50 years. During the event, the maximum number of daily deaths was 317, 42% above the non-heat day average, even though an heat warning system in operation. In this study results from the analysis of heat waves events in Italian cities is presented. Indices representative of extremely hot conditions have been taken into account and results of the analysis of indices such as the number of summer days (SU), number of tropical nights (TR), maxima and minima of daily maximum and minimum temperatures (TXx, TXn, TNx, TNn, respectively), exceedances over fixed thresholds is presented. Results show a clear increase in the past decades of the numbers of days affected by heat events. Some considerations are also presented about the impact on human health of the longest events occurred in the Country.

Baldi, Marina

2014-05-01

407

Wave Equations for Invariant Infeld-van der Waerden Wave Functions for Photons and Their Physical Significance  

E-print Network

The inner structure of the {\\gamma}{\\epsilon}-formalisms of Infeld and van der Waerden admits the occurrence of spin-tensor electromagnetic fields which bear invariance under the action of the generalized Weyl gauge group. A concise derivation of the wave equations for such fields is carried out explicitly along with the construction of a set of torsionless covariant-derivative expressions. It is emphatically pointed out that the integration of the wave equations arising herein may under certain circumstances produce significant insights into the situation concerning the description of some physical properties of the cosmic microwave background.

J. G. Cardoso

2010-06-09

408

Measuring the ground-state wave functional of SU(2) Yang-Mills theory in 3+1 dimensions: Abelian plane waves  

E-print Network

A method of measuring relative probabilities of various gauge-field configurations in the Yang-Mills vacuum was proposed long ago [Phys. Lett. B 223 (1989) 207]. We applied this method to compute the square of the YM vacuum wave functional (VWF) in numerical simulations of SU(2) lattice gauge theory in D=3+1 dimensions for sets of abelian plane waves. The results were compared to predictions based on some VWF proposals in the literature. None of them describes the data satisfactorily at large plane-wave momenta. The phenomenological best fit to data, containing three free parameters, appears to reduce in the continuum limit to the approximate form proposed in [Phys. Rev. D 77 (2008) 065003].

Jeff Greensite; Stefan Olejnik

2013-11-16

409

Recursive geometric integrators for wave propagation in a functionally graded multilayered elastic medium  

NASA Astrophysics Data System (ADS)

The differential equations governing transfer and stiffness matrices and acoustic impedance for a functionally graded generally anisotropic magneto-electro-elastic medium have been obtained. It is shown that the transfer matrix satisfies a linear 1st order matrix differential equation, while the stiffness matrix satisfies a nonlinear Riccati equation. For a thin nonhomogeneous layer, approximate solutions with different levels of accuracy have been formulated in the form of a transfer matrix using a geometrical integration in the form of a Magnus expansion. This integration method preserves qualitative features of the exact solution of the differential equation, in particular energy conservation. The wave propagation solution for a thick layer or a multilayered structure of inhomogeneous layers is obtained recursively from the thin layer solutions. Since the transfer matrix solution becomes computationally unstable with increase of frequency or layer thickness, we reformulate the solution in the form of a stable stiffness-matrix solution which is obtained from the relation of the stiffness matrices to the transfer matrices. Using an efficient recursive algorithm, the stiffness matrices of the thin nonhomogeneous layer are combined to obtain the total stiffness matrix for an arbitrary functionally graded multilayered system. It is shown that the round-off error for the stiffness-matrix recursive algorithm is higher than that for the transfer matrices. To optimize the recursive procedure, a computationally stable hybrid method is proposed which first starts the recursive computation with the transfer matrices and then, as the thickness increases, transits to the stiffness matrix recursive algorithm. Numerical results show this solution to be stable and efficient. As an application example, we calculate the surface wave velocity dispersion for a functionally graded coating on a semispace.

Wang, Lugen; Rokhlin, S. I.

2004-11-01

410

The Impact of Children with High-Functioning Autism on Parental Stress, Sibling Adjustment, and Family Functioning  

ERIC Educational Resources Information Center

The article discuses a study conducted to investigate the impact of children with high-functioning autism (HFA) on parental stress, sibling adjustment, and family functioning; the study involves a sample of parents of 15 children with HFA and parents of 15 matched control children who completed questionnaires measuring the dependent variables. The…

Rao, Patricia A.; Beidel, Deborah C.

2009-01-01

411

Selected Administrative Factors and Guidance Functions: A Study of the Impact of Organization, Staff, and Finance Upon Guidance Functions.  

ERIC Educational Resources Information Center

This study examines selected administrative factors to discover their impact upon the functioning of a secondary school counselor. Three major null hypotheses are stated: there is no relationship between senior high school counselor' functions and (1) the organizational pattern of guidance of pupil services; (2) the competencies implied by…

Ferguson, Annabelle E.

412

Transformative Wave Technologies Kent, Washington  

E-print Network

IQ Platform to avoid negative impact on fault detection and historic comparison functions. CATALYST Service investment ·Positive life cycle impact from maintenance and fault detection features ·Reduces critical systemTransformative Wave Technologies Kent, Washington www.transformativewave.com #12;#12;North America

California at Davis, University of

413

Functional foods. Part 2: the impact on current regulatory terminology  

Microsoft Academic Search

In order to introduce the category of functional foods into the present regulatory system, it is necessary to review the relationships between functional foods and other existing legal or commercial terms, with the internationally agreed definitions. Functional foods may be distinguishable from medical foods and dietary supplements, whereas they overlap foods for special dietary uses and fortified foods. They are

No-Seong Kwak; David John Jukes

2001-01-01

414

Green's function integral equation method for propagation of electromagnetic waves in an anisotropic dielectric-magnetic slab  

NASA Astrophysics Data System (ADS)

We extend the Green's function integral method to investigate the propagation of electromagnetic waves through an anisotropic dielectric-magnetic slab. From a microscopic perspective, we analyze the interaction of wave with the slab and derive the propagation characteristics by self-consistent analyses. Applying the results, we find an alternative explanation to the general mechanism for the photon tunneling. The results are confirmed by numerical simulations and disclose the underlying physics of wave propagation through slab. The method extended is applicable to other problems of propagation in dielectric-magnetic materials, including metamaterials.

Shu, Weixing; Lv, Xiaofang; Luo, Hailu; Wen, Shuangchun

2010-08-01

415

Spectrum for Heavy Quankonia and Mixture of the Relevant Wave Functions within the Framework of Bethe-Salpeter Equation  

E-print Network

Considering the fact that some excited states of the heavy quarkonia (charmonium and bottomonium) still missing in experimental observations and potential applications of the relevant wave functions of the bound states, we re-analyze the spectrum and the relevant wave functions of the heavy quarkonia within the framework of Bethe-Salpeter (B.S.) equation with a proper QCD-inspired kernel. Such a kernel for the heavy quarkonia, relating to potential of non-relativistic quark model, is instantaneous, so we call the corresponding B.S. equation as BS-In equation throughout the paper. Particularly, a new way to solve the B.S. equation, which is different from the traditional ones, is proposed here, and with it not only the known spectrum for the heavy quarkonia is re-generated, but also an important issue is brought in, i.e., the obtained solutions of the equation `automatically' include the 'fine', 'hyperfine' splittings and the wave function mixture, such as $S-D$ wave mixing in $J^{PC}=1^{--}$ states, $P-F$ wave mixing in $J^{PC}=2^{++}$ states for charmonium and bottomonium etc. It is pointed out that the best place to test the wave mixture probably is at $Z$-factory ($e^+e^-$ collider running at $Z$-boson pole with extremely high luminosity).

Chao-Hsi Chang; Guo-Li Wang

2010-03-19

416

Scaling of plane-wave functions in statistically optimized near-field acoustic holography.  

PubMed

Statistically Optimized Near-field Acoustic Holography (SONAH) is a Patch Holography method, meaning that it can be applied in cases where the measurement area covers only part of the source surface. The method performs projections directly in the spatial domain, avoiding the use of spatial discrete Fourier transforms and the associated errors. First, an inverse problem is solved using regularization. For each calculation point a multiplication must then be performed with two transfer vectors-one to get the sound pressure and the other to get the particle velocity. Considering SONAH based on sound pressure measurements, existing derivations consider only pressure reconstruction when setting up the inverse problem, so the evanescent wave amplification associated with the calculation of particle velocity is not taken into account in the regularized solution of the inverse problem. The present paper introduces a scaling of the applied plane wave functions that takes the amplification into account, and it is shown that the previously published virtual source-plane retraction has almost the same effect. The effectiveness of the different solutions is verified through a set of simulated measurements. PMID:25373969

Hald, Jørgen

2014-11-01

417

A theoretical study of the propagation of Rayleigh waves in a functionally graded piezoelectric material (FGPM).  

PubMed

An exact approach is used to investigate Rayleigh waves in a functionally graded piezoelectric material (FGPM) layer bonded to a semi infinite homogenous solid. The piezoelectric material is polarized when the six fold symmetry axis is put along the propagation direction x(1). The FGPM character imposes that the material properties change gradually with the thickness of the layer. Contrary to the analytical approach, the adopted numerical methods, including the ordinary differential equation (ODE) and the stiffness matrix method (SMM), treat separately the electrical and mechanical gradients. The influences of graded variations applied to FGPM film coefficients on the dispersion curves of Rayleigh waves are discussed. The effects of gradient coefficients on electromechanical coupling factor, displacement fields, stress distributions and electrical potential, are reported. The obtained deviations in comparison with the ungraded homogenous film are plotted with respect to the dimensionless wavenumber. Opposite effects are observed on the coupling factor when graded variations are applied separately. A particular attention has been devoted to the maximum of the coupling factor and it dependence on the stratification rate and the gradient coefficient. This work provides with a theoretical foundation for the design and practical applications of SAW devices with high performance. PMID:21944994

Ben Salah, Issam; Njeh, Anouar; Ben Ghozlen, Mohamed Hédi

2012-02-01

418

Lamb waves propagation in functionally graded piezoelectric materials by Peano-series method.  

PubMed

The Peano-series expansion is used to investigate the propagation of the lowest-order symmetric (S0) and antisymmetric (A0) Lamb wave modes in a functionally graded piezoelectric material (FGPM) plate. Aluminum nitride has been retained for illustration, it is polarized along the thickness axis, and at the same time the material properties change gradually perpendicularly to the plate with an exponential variation. The effects of the gradient variation on the phase velocity and the coupling electromechanical factor are obtained. Appropriate curves are given to reflect their behavior with respect to frequency. The highest value of the electromechanical coupling factor has been observed for S0 mode, it is close to six percent, conversely for A0 mode it does not exceed 1.5%. The coupling factor maxima undergo a shift toward the high frequency area when the corresponding gradient coefficient increases. The Peano-series method computed under Matlab software, gives rapid convergence and accurate phase velocity when analysing Lamb waves in FGPM plate. The obtained numerical results can be used to design different sensors with high performance working at different frequency ranges by adjusting the extent of the gradient property. PMID:25200699

Ben Amor, Morched; Ben Ghozlen, Mohamed Hédi

2015-01-01

419

A review on continuous wave functional near-infrared spectroscopy and imaging instrumentation and methodology.  

PubMed

This year marks the 20th anniversary of functional near-infrared spectroscopy and imaging (fNIRS/fNIRI). As the vast majority of commercial instruments developed until now are based on continuous wave technology, the aim of this publication is to review the current state of instrumentation and methodology of continuous wave fNIRI. For this purpose we provide an overview of the commercially available instruments and address instrumental aspects such as light sources, detectors and sensor arrangements. Methodological aspects, algorithms to calculate the concentrations of oxy- and deoxyhemoglobin and approaches for data analysis are also reviewed. From the single-location measurements of the early years, instrumentation has progressed to imaging initially in two dimensions (topography) and then three (tomography). The methods of analysis have also changed tremendously, from the simple modified Beer-Lambert law to sophisticated image reconstruction and data analysis methods used today. Due to these advances, fNIRI has become a modality that is widely used in neuroscience research and several manufacturers provide commercial instrumentation. It seems likely that fNIRI will become a clinical tool in the foreseeable future, which will enable diagnosis in single subjects. PMID:23684868

Scholkmann, Felix; Kleiser, Stefan; Metz, Andreas Jaakko; Zimmermann, Raphael; Mata Pavia, Juan; Wolf, Ursula; Wolf, Martin

2014-01-15

420

Calculation of the wave functions for semi-infinite crystals with linear methods of band theory  

NASA Astrophysics Data System (ADS)

We present a variational method to solve the Schrödinger equation for a semi-infinite crystal. The complex band structure is generated by the inverse extended linear augmented plane wave k.p method. The trial function is continuous and smooth over the whole space and it satisfies by construction the equation (H⁁-E)?=0 both in the crystal and in the vacuum half-spaces. In the surface region the equation ?||(H⁁-E)?||=0 is solved. The formalism is applicable to potentials of general shape in the surface region. The procedure is applied to calculations of low energy electron diffraction spectra for the (111) surfaces of the fcc metals Cu, Ag, Ni, Pd, and Al.

Krasovskii, E. E.; Schattke, W.

1999-06-01

421

The physical basis for absorption of light. [effects on wave functions of gas molecules and atoms  

NASA Technical Reports Server (NTRS)

The effects of light absorption on the wave functions of gas-phase molecules and atoms are investigated by high resolution spectral measurements of radiation emerging from a sample. A Stark-modulated sample of methyl fluoride was irradiated at the 102 GHz rotational transition and the emergent radiation was resolved by means of a spectrum analyzer. For signal oscillator frequencies below or above the molecular resonance by one modulation frequency, the amplitudes of the upper and lower modulation sidebands are found to be of nonuniform intensity, which is inconsistent with amplitude modulation. Emission due to polarization is, however, calculated to be consistent with the results observed, indicating that light absorption should be considered as a subtractive stimulated emission.

Pickett, H. M.

1979-01-01

422

Optimal spatial filtering and transfer function for SAR ocean wave spectra  

NASA Astrophysics Data System (ADS)

The impulse response of the SAR system is not a delta function and the spectra represent the product of the underlying image spectrum with the transform of the impulse response which must be removed. A digitally computed spectrum of SEASAT imagery of the Atlantic Ocean east of Cape Hatteras was smoothed with a 5 x 5 convolution filter and the trend was sampled in a direction normal to the predominant wave direction. This yielded a transform of a noise-like process. The smoothed value of this trend is the transform of the impulse response. This trend is fit with either a second- or fourth-order polynomial which is then used to correct the entire spectrum. A 16 x 16 smoothing of the spectrum shows the presence of two distinct swells. Correction of the effects of speckle is effected by the subtraction of a bias from the spectrum.

Beal, R. C.; Tilley, D. G.

1981-06-01

423

Optimal spatial filtering and transfer function for SAR ocean wave spectra  

NASA Technical Reports Server (NTRS)

The impulse response of the SAR system is not a delta function and the spectra represent the product of the underlying image spectrum with the transform of the impulse response which must be removed. A digitally computed spectrum of SEASAT imagery of the Atlantic Ocean east of Cape Hatteras was smoothed with a 5 x 5 convolution filter and the trend was sampled in a direction normal to the predominant wave direction. This yielded a transform of a noise-like process. The smoothed value of this trend is the transform of the impulse response. This trend is fit with either a second- or fourth-order polynomial which is then used to correct the entire spectrum. A 16 x 16 smoothing of the spectrum shows the presence of two distinct swells. Correction of the effects of speckle is effected by the subtraction of a bias from the spectrum.

Beal, R. C.; Tilley, D. G.

1981-01-01

424

Long-Wave Infrared Functional Brain Imaging in Human: A Pilot Study  

PubMed Central

Although some authors suggest to use Long-Wave Infrared (LWIR) sensors to evaluate brain functioning, the link between emissions of LWIR and mental effort is not established. The goal of this pilot study was to determine whether frontal LWIR emissions vary during execution of neuropsychological tasks known to differentially activate the pre-frontal cortex (simple color presentations, induction of the Stroop effect, and a gambling task with real money). Surprisingly, LWIR emissions as measured with bilateral frontal sensors in 47 participants significantly differed between tasks, in the supposed direction (Color

Joyal, Christian C; Henry, Mylene

2013-01-01

425

Elastic spin observables and proton wave function normalization at large t  

SciTech Connect

We summarize the role of spin observables in testing the foundations of exclusive QCD at large t. Polarized elastic scattering experiments can shed light on fundamental properties of protons, such as helicity conservation, normalization of the wave function and structure. Specific QCD motivated predictions for the spin observables are presented, which can be tested at polarized proton beam facilities. In this paper, two kinematic regions are considered: 90{degrees} c.m. at large {vert_bar} t {vert_bar} and the intermediate hard scattering regime: m{sub p}{sup 2} {much_lt}{vert_bar} t {vert_bar}{much_lt} s. Theoretical models, which predict the spin observables in these regions, are reviewed. These are compared with present elastic pp data and a program is suggested for future elastic polarized pp scattering experiments, which can be used to further our knowledge of proton structure.

Ramsey, G.P. [Loyola Univ., Chicago, IL (United States). Dept. of Physics]|[Argonne National Lab., IL (United States)

1993-11-29

426

Wave-function description of conductance mapping for a quantum Hall electron interferometer  

NASA Astrophysics Data System (ADS)

Scanning gate microscopy of quantum point contacts (QPC) in the integer quantum Hall regime is considered in terms of the scattering wave functions with a finite-difference implementation of the quantum transmitting boundary approach. Conductance (G) maps for a clean QPC as well as for a system including an antidot within the QPC constriction are evaluated. The steplike locally flat G maps for clean QPCs turn into circular resonances that are reentrant in an external magnetic field when the antidot is introduced to the constriction. The current circulation around the antidot and the spacing of the resonances at the magnetic field scale react to the probe approaching the QPC. The calculated G maps with a rigid but soft antidot potential reproduce the features detected recently in the electron interferometer [F. Martins et al., Sci. Rep. 3, 1416 (2013), 10.1038/srep01416].

Kolasi?ski, K.; Szafran, B.

2014-04-01

427

Long-wave infrared functional brain imaging in human: a pilot study.  

PubMed

Although some authors suggest to use Long-Wave Infrared (LWIR) sensors to evaluate brain functioning, the link between emissions of LWIR and mental effort is not established. The goal of this pilot study was to determine whether frontal LWIR emissions vary during execution of neuropsychological tasks known to differentially activate the pre-frontal cortex (simple color presentations, induction of the Stroop effect, and a gambling task with real money). Surprisingly, LWIR emissions as measured with bilateral frontal sensors in 47 participants significantly differed between tasks, in the supposed direction (Color

Joyal, Christian C; Henry, Mylene

2013-01-01

428

Flavor hierarchy in SO(10) grand unified theories via 5-dimensional wave-function localization  

E-print Network

A mechanism to generate fermion-mass hierarchy in SO(10) Grand Unified Theories is considered. We find that the lopsided family structure, which is suitable to the Large angle MSW solution to the solar neutrino oscillation, is realized without introducing extra matter fields if the hierarchy originates from the wave-function profile in an extra dimension. Unlike the Froggatt-Nielsen mechanism, the SO(10) breaking effect may directly contribute to the source of the hierarchy, i.e., the bulk mass terms. It naturally explains the difference of the hierarchical patterns between the quark and the lepton sectors. We also find the possibility of the horizontal unification, in which three generations of the matter fields are unified to a 3 dimensional representation of an SU(2) gauge group.

Ryuichiro Kitano; Tianjun Li

2003-02-10

429

Fast plane wave density functional theory molecular dynamics calculations on multi-GPU machines  

SciTech Connect

Plane wave pseudopotential (PWP) density functional theory (DFT) calculation is the most widely used method for material simulations, but its absolute speed stagnated due to the inability to use large scale CPU based computers. By a drastic redesign of the algorithm, and moving all the major computation parts into GPU, we have reached a speed of 12 s per molecular dynamics (MD) step for a 512 atom system using 256 GPU cards. This is about 20 times faster than the CPU version of the code regardless of the number of CPU cores used. Our tests and analysis on different GPU platforms and configurations shed lights on the optimal GPU deployments for PWP-DFT calculations. An 1800 step MD simulation is used to study the liquid phase properties of GaInP.

Jia, Weile, E-mail: jiawl@sccas.cn [Supercomputing Center, Computer Network Information Center, Chinese Academy of Sciences, No. 4 South 4th Street, ZhongGuanCun, Beijing 100190 (China) [Supercomputing Center, Computer Network Information Center, Chinese Academy of Sciences, No. 4 South 4th Street, ZhongGuanCun, Beijing 100190 (China); University of Chinese Academy of Sciences, Beijing (China); Fu, Jiyun, E-mail: fujy@sccas.cn [Supercomputing Center, Computer Network Information Center, Chinese Academy of Sciences, No. 4 South 4th Street, ZhongGuanCun, Beijing 100190 (China) [Supercomputing Center, Computer Network Information Center, Chinese Academy of Sciences, No. 4 South 4th Street, ZhongGuanCun, Beijing 100190 (China); University of Chinese Academy of Sciences, Beijing (China); Cao, Zongyan, E-mail: zycao@sccas.cn [Supercomputing Center, Computer Network Information Center, Chinese Academy of Sciences, No. 4 South 4th Street, ZhongGuanCun, Beijing 100190 (China)] [Supercomputing Center, Computer Network Information Center, Chinese Academy of Sciences, No. 4 South 4th Street, ZhongGuanCun, Beijing 100190 (China); Wang, Long, E-mail: wangl@sccas.cn [Supercomputing Center, Computer Network Information Center, Chinese Academy of Sciences, No. 4 South 4th Street, ZhongGuanCun, Beijing 100190 (China)] [Supercomputing Center, Computer Network Information Center, Chinese Academy of Sciences, No. 4 South 4th Street, ZhongGuanCun, Beijing 100190 (China); Chi, Xuebin, E-mail: chi@sccas.cn [Supercomputing Center, Computer Network Information Center, Chinese Academy of Sciences, No. 4 South 4th Street, ZhongGuanCun, Beijing 100190 (China)] [Supercomputing Center, Computer Network Information Center, Chinese Academy of Sciences, No. 4 South 4th Street, ZhongGuanCun, Beijing 100190 (China); Gao, Weiguo, E-mail: wggao@fudan.edu.cn [School of Mathematical Sciences, Fudan University, 220 Handan Road, Shanghai 200433 (China) [School of Mathematical Sciences, Fudan University, 220 Handan Road, Shanghai 200433 (China); MOE Key Laboratory of Computational Physical Sciences, Fudan University, Shanghai (China); Wang, Lin-Wang, E-mail: lwwang@lbl.gov [Material Science Division, Lawrence Berkeley National Laboratory, One Cyclotron Road Mail Stop 50F Berkeley, CA 94720 (United States)] [Material Science Division, Lawrence Berkeley National Laboratory, One Cyclotron Road Mail Stop 50F Berkeley, CA 94720 (United States)

2013-10-15

430