Dubrovsky, V. G.; Topovsky, A. V.; Basalaev, M. Yu.
2010-09-15
The classes of exactly solvable multiline soliton potentials and corresponding wave functions of two-dimensional stationary Schroedinger equation via {partial_derivative}-dressing method are constructed and their physical interpretation is discussed.
Pseudopotential Method for Higher Partial Wave Scattering
Idziaszek, Zbigniew; Calarco, Tommaso
2006-01-13
We present a zero-range pseudopotential applicable for all partial wave interactions between neutral atoms. For p and d waves, we derive effective pseudopotentials, which are useful for problems involving anisotropic external potentials. Finally, we consider two nontrivial applications of the p-wave pseudopotential: we solve analytically the problem of two interacting spin-polarized fermions confined in a harmonic trap, and we analyze the scattering of p-wave interacting particles in a quasi-two-dimensional system.
Generalized pseudopotentials for higher partial wave scattering.
Stock, René; Silberfarb, Andrew; Bolda, Eric L; Deutsch, Ivan H
2005-01-21
We derive a generalized zero-range pseudopotential applicable to all partial wave solutions to the Schrödinger equation based on a delta-shell potential in the limit that the shell radius approaches zero. This properly models all higher order multipole moments not accounted for with a monopolar delta function at the origin, as used in the familiar Fermi pseudopotential for s-wave scattering. By making the strength of the potential energy dependent, we derive self-consistent solutions for the entire energy spectrum of the realistic potential. We apply this to study two particles in an isotropic harmonic trap, interacting through a central potential, and derive analytic expressions for the energy eigenstates and eigenvalues.
Partial Wave Dispersion Relations: Application to Electron-Atom Scattering
NASA Technical Reports Server (NTRS)
Temkin, A.; Drachman, Richard J.
1999-01-01
In this Letter we propose the use of partial wave dispersion relations (DR's) as the way of solving the long-standing problem of correctly incorporating exchange in a valid DR for electron-atom scattering. In particular a method is given for effectively calculating the contribution of the discontinuity and/or poles of the partial wave amplitude which occur in the negative E plane. The method is successfully tested in three cases: (i) the analytically solvable exponential potential, (ii) the Hartree potential, and (iii) the S-wave exchange approximation for electron-hydrogen scattering.
Partial wave analysis using graphics processing units
NASA Astrophysics Data System (ADS)
Berger, Niklaus; Beijiang, Liu; Jike, Wang
2010-04-01
Partial wave analysis is an important tool for determining resonance properties in hadron spectroscopy. For large data samples however, the un-binned likelihood fits employed are computationally very expensive. At the Beijing Spectrometer (BES) III experiment, an increase in statistics compared to earlier experiments of up to two orders of magnitude is expected. In order to allow for a timely analysis of these datasets, additional computing power with short turnover times has to be made available. It turns out that graphics processing units (GPUs) originally developed for 3D computer games have an architecture of massively parallel single instruction multiple data floating point units that is almost ideally suited for the algorithms employed in partial wave analysis. We have implemented a framework for tensor manipulation and partial wave fits called GPUPWA. The user writes a program in pure C++ whilst the GPUPWA classes handle computations on the GPU, memory transfers, caching and other technical details. In conjunction with a recent graphics processor, the framework provides a speed-up of the partial wave fit by more than two orders of magnitude compared to legacy FORTRAN code.
Yin, Jun; Zhang, Zhuhua; Li, Xuemei; Yu, Jin; Zhou, Jianxin; Chen, Yaqing; Guo, Wanlin
2014-05-06
Nanoscale materials offer much promise in the pursuit of high-efficient energy conversion technology owing to their exceptional sensitivity to external stimulus. In particular, experiments have demonstrated that flowing water over carbon nanotubes can generate electric voltages. However, the reported flow-induced voltages are in wide discrepancy and the proposed mechanisms remain conflictive. Here we find that moving a liquid-gas boundary along a piece of graphene can induce a waving potential of up to 0.1 V. The potential is proportional to the moving velocity and the graphene length inserted into ionic solutions, but sharply decreases with increasing graphene layers and vanishes in other materials. This waving potential arises from charge transfer in graphene driven by a moving boundary of an electric double layer between graphene and ionic solutions. The results reveal a unique electrokinetic phenomenon and open prospects for functional sensors, such as tsunami monitors.
Superconformal partial waves in Grassmannian field theories
NASA Astrophysics Data System (ADS)
Doobary, Reza; Heslop, Paul
2015-12-01
We derive superconformal partial waves for all scalar four-point functions on a super Grassmannian space Gr( m| n, 2 m|2 n) for all m, n. This family of four-point functions includes those of all (arbitrary weight) half BPS operators in both N=4 SYM ( m = n = 2) and in N = 2 superconformal field theories in four dimensions ( m = 2 , n = 1) on analytic superspace. It also includes four-point functions of all (arbitrary dimension) scalar fields in non-supersymmetric conformal field theories ( m = 2 , n = 0) on Minkowski space, as well as those of a certain class of representations of the compact SU(2 n) coset spaces. As an application we then specialise to N=4 SYM and use these results to perform a detailed superconformal partial wave analysis of the four-point functions of arbitrary weight half BPS operators. We discuss the non-trivial separation of protected and unprotected sectors for the <2222>, <2233> and <3333> cases in an SU( N) gauge theory at finite N. The <2233> correlator predicts a non-trivial protected twist four sector for <3333> which we can completely determine using the knowledge that there is precisely one such protected twist four operator for each spin.
Power counting in peripheral partial waves: The singlet channels
NASA Astrophysics Data System (ADS)
Valderrama, M. Pavón; Sánchez, M. Sánchez; Yang, C.-J.; Long, Bingwei; Carbonell, J.; van Kolck, U.
2017-05-01
We analyze the power counting of the peripheral singlet partial waves in nucleon-nucleon scattering. In agreement with conventional wisdom, we find that pion exchanges are perturbative in the peripheral singlets. We quantify from the effective field theory perspective the well-known suppression induced by the centrifugal barrier in the pion-exchange interactions. By exploring perturbation theory up to fourth order, we find that the one-pion-exchange potential in these channels is demoted from leading to subleading order by a given power of the expansion parameter that grows with the orbital angular momentum. We discuss the implications of these demotions for few-body calculations: though higher partial waves have been known for a long time to be irrelevant in these calculations (and are hence ignored), here we explain how to systematize the procedure in a way that is compatible with the effective field theory expansion.
The new BNL partial wave analysis programs
Cummings, J.P.; Weygand, D.P.
1997-07-29
Experiment E852 at Brookhaven National Laboratory is a meson spectroscopy experiment which took data at the Multi-Particle Spectrometer facility of the Alternating Gradient Syncrotron. Upgrades to the spectrometer`s data acquisition and trigger electronics allowed over 900 million data events, of numerous topologies, to be recorded to tape in 1995 running alone. One of the primary goals of E852 is identification of states beyond the quark model, i.e., states with gluonic degrees of freedom. Identification of such states involves the measurement of a systems spin-parity. Such a measurement is usually done using Partial Wave Analysis. Programs to perform such analyses exist, in fact, one was written at BNL and used in previous experiments by some of this group. This program, however, was optimized for a particular final state, and modification to allow analysis of the broad range of final states in E852 would have been difficult. The authors therefore decided to write a new program, with an eye towards generality that would allow analysis of a large class of reactions.
Partial Wave Analysis of Coupled Photonic Structures
NASA Technical Reports Server (NTRS)
Fuller, Kirk A.; Smith, David D.; Curreri, Peter A. (Technical Monitor)
2002-01-01
The very high quality factors sustained by microcavity optical resonators are relevant to applications in wavelength filtering, routing, switching, modulation, and multiplexing/demultiplexing. Increases in the density of photonic elements require that attention be paid to how electromagnetic (EM) coupling modifies their optical properties. This is especially true when cavity resonances are involved, in which case, their characteristics may be fundamentally altered. Understanding the optical properties of microcavities that are near or in contact with photonic elements---such as other microcavities, nanostructures, couplers, and substrates---can be expected to advance our understanding of the roles that these structures may play in VLSI photonics, biosensors and similar device technologies. Wc present results from recent theoretical studies of the effects of inter- and intracavity coupling on optical resonances in compound spherical particles. Concentrically stratified spheres and bispheres constituted from homogeneous and stratified spheres are subjects of this investigation. A new formulation is introduced for the absorption of light in an arbitrary layer of a multilayered sphere, which is based on multiple reflections of the spherical partial waves of the Lorenz-Mie solution for scattering by a sphere. Absorption efficiencies, which can be used to profile cavity resonances and to infer fluorescence yields or the onset of nonlinear optical processes in the microcavities, are presented. Splitting of resonances in these multisphere systems is paid particular attention, and consequences for photonic device development and possible performance enhancements through carefully designed architectures that exploit EM coupling are considered.
Direct Calculation of the Scattering Amplitude Without Partial Wave Analysis
NASA Technical Reports Server (NTRS)
Shertzer, J.; Temkin, A.; Fisher, Richard R. (Technical Monitor)
2001-01-01
Two new developments in scattering theory are reported. We show, in a practical way, how one can calculate the full scattering amplitude without invoking a partial wave expansion. First, the integral expression for the scattering amplitude f(theta) is simplified by an analytic integration over the azimuthal angle. Second, the full scattering wavefunction which appears in the integral expression for f(theta) is obtained by solving the Schrodinger equation with the finite element method (FEM). As an example, we calculate electron scattering from the Hartree potential. With minimal computational effort, we obtain accurate and stable results for the scattering amplitude.
The Thomas and Effimov Effects for General Partial Waves
NASA Astrophysics Data System (ADS)
Sternberg, James; Macek, Joseph
2006-05-01
Description of the two-body interactions between particles is a fundamental step in modeling many-body systems. Because s-wave scattering dominates at ultra-cold temperatures, zero-range potentials (ZRPs) have been a popular way to describe the two-body interactions. Recent experiments enhance higher partial waves and this has led to interest in extending the zero-range model beyond l=0Stock:2005. In this work we use a ZRP model to examine three body systems. Of particular importance in these systems is the Thomas effect, which is the divergence of the wave function when all three particles are close together. The Thomas effect is known for spin zero particles when l=0. In addition there is the Effimov effect, in which there are an infinite number of three body bound states if the zero-range potential boundary conditions separate in hyperspherical coordinates as the scattering length al->∞. We show that the Effimov effect occurs for not only the well-known l=0 case, but for spin 1/2 fermions via the l=1 pseudopotential of ref. [1] This research is supported by Department of Energy Grant DE-FG02-02ER15283 [1] Ren'e Stock, Andrew Silberfarb, Eric. L. Bolda, and Ivan H. Deutsch, Phys Rev. Lett. 94 023202 (2005)
ALFVEN WAVES IN A PARTIALLY IONIZED TWO-FLUID PLASMA
Soler, R.; Ballester, J. L.; Terradas, J.; Carbonell, M. E-mail: joseluis.ballester@uib.es E-mail: marc.carbonell@uib.es
2013-04-20
Alfven waves are a particular class of magnetohydrodynamic waves relevant in many astrophysical and laboratory plasmas. In partially ionized plasmas the dynamics of Alfven waves is affected by the interaction between ionized and neutral species. Here we study Alfven waves in a partially ionized plasma from the theoretical point of view using the two-fluid description. We consider that the plasma is composed of an ion-electron fluid and a neutral fluid, which interact by means of particle collisions. To keep our investigation as general as possible, we take the neutral-ion collision frequency and the ionization degree as free parameters. First, we perform a normal mode analysis. We find the modification due to neutral-ion collisions of the wave frequencies and study the temporal and spatial attenuation of the waves. In addition, we discuss the presence of cutoff values of the wavelength that constrain the existence of oscillatory standing waves in weakly ionized plasmas. Later, we go beyond the normal mode approach and solve the initial-value problem in order to study the time-dependent evolution of the wave perturbations in the two fluids. An application to Alfven waves in the low solar atmospheric plasma is performed and the implication of partial ionization for the energy flux is discussed.
MAGNETOACOUSTIC WAVES IN A PARTIALLY IONIZED TWO-FLUID PLASMA
Soler, Roberto; Ballester, Jose Luis; Carbonell, Marc E-mail: joseluis.ballester@uib.es
2013-11-01
Compressible disturbances propagate in a plasma in the form of magnetoacoustic waves driven by both gas pressure and magnetic forces. In partially ionized plasmas the dynamics of ionized and neutral species are coupled due to ion-neutral collisions. As a consequence, magnetoacoustic waves propagating through a partially ionized medium are affected by ion-neutral coupling. The degree to which the behavior of the classic waves is modified depends on the physical properties of the various species and on the relative value of the wave frequency compared to the ion-neutral collision frequency. Here, we perform a comprehensive theoretical investigation of magnetoacoustic wave propagation in a partially ionized plasma using the two-fluid formalism. We consider an extensive range of values for the collision frequency, ionization ratio, and plasma β, so that the results are applicable to a wide variety of astrophysical plasmas. We determine the modification of the wave frequencies and study the frictional damping due to ion-neutral collisions. Approximate analytic expressions for the frequencies are given in the limit case of strongly coupled ions and neutrals, while numerically obtained dispersion diagrams are provided for arbitrary collision frequencies. In addition, we discuss the presence of cutoffs in the dispersion diagrams that constrain wave propagation for certain combinations of parameters. A specific application to propagation of compressible waves in the solar chromosphere is given.
Lee, Jong-In; Kim, Young-Taek; Shin, Sungwon
2014-01-01
This study presents wave height distribution in terms of stem wave evolution phenomena on partially perforated wall structures through three-dimensional laboratory experiments. The plain and partially perforated walls were tested to understand their effects on the stem wave evolution under the monochromatic and random wave cases with the various wave conditions, incident angle (from 10 to 40 degrees), and configurations of front and side walls. The partially perforated wall reduced the relative wave heights more effectively compared to the plain wall structure. Partially perforated walls with side walls showed a better performance in terms of wave height reduction compared to the structure without the side wall. Moreover, the relative wave heights along the wall were relatively small when the relative chamber width is large, within the range of the chamber width in this study. The wave spectra showed a frequency dependency of the wave energy dissipation. In most cases, the existence of side wall is a more important factor than the porosity of the front wall in terms of the wave height reduction even if the partially perforated wall was still effective compared to the plain wall. PMID:25254260
Correlations of πN partial waves for multireaction analyses
Doring, M.; Revier, J.; Ronchen, D.; ...
2016-06-15
In the search for missing baryonic resonances, many analyses include data from a variety of pion- and photon-induced reactions. For elastic πN scattering, however, usually the partial waves of the SAID (Scattering Analysis Interactive Database) or other groups are fitted, instead of data. We provide the partial-wave covariance matrices needed to perform correlated χ2 fits, in which the obtained χ2 equals the actual χ2 up to nonlinear and normalization corrections. For any analysis relying on partial waves extracted from elastic pion scattering, this is a prerequisite to assess the significance of resonance signals and to assign any uncertainty on results.more » Lastly, the influence of systematic errors is also considered.« less
Impact of Plunging Breaking Wave on a Partially Submerged Cube
NASA Astrophysics Data System (ADS)
Wang, A.; Ikeda, C. M.; Duncan, J. H.
2012-11-01
The impact of a plunging breaking wave on a partially submerged rigid cube (L = 30 . 5 cm) is studied experimentally in a wave tank that is 14.8 m long, 1.15 m wide and 2.2 m high with a water depth of 0.91 m. A single repeatable plunging breaker is generated from a dispersively focused wave packet (average frequency of 1.14 Hz) that is created with a programmable wave maker. The water surface profiles at the vertical center plane of the cube are measured with a cinematic LIF technique. The cube is centered in the width of the tank and mounted from above with the front face oriented with its normal in the vertical long center plane of the tank and tilted at angles of 0 and 20 degrees downward relative to horizontal. For the range of horizontal cube positions used here, during the wave impact, the water free surface forms a circular arc between the water contact point on the front face of the cube and the wave crest. As the wave impact continues, this arc converges to a point and a fast-moving vertical jet is formed. The effect of the submergence and tilt angle of the cube on the jet formation are explored. This work is supported by the Office of Naval Research.
Wave optics simulation approach for partial spatially coherent beams.
Xiao, Xifeng; Voelz, David
2006-08-07
A numerical wave optics approach for simulating a partial spatially coherent beam is presented. The approach involves the application of a sequence of random phase screens to an initial beam field and the summation of the intensity results after propagation. The relationship between the screen parameters and the spatial coherence function for the beam is developed and the approach is verified by comparing results with analytic formulations for a Gaussian Schell-model beam. The approach can be used for modeling applications such as free space optical laser links that utilize partially coherent beams.
Calculation of the Scattering Amplitude Without Partial Wave Expansion
NASA Technical Reports Server (NTRS)
Shertzer, J.; Temkin, Aaron; Fisher, Richard R. (Technical Monitor)
2001-01-01
Two developments in the direct calculation of the angular differential scattering amplitude have been implemented: (a) The integral expansion of the scattering amplitude is simplified by analytically integration over the azimuthal angle. (b) The resulting integral as a function of scattering angle is calculated by using the numerically generated wave function from a finite element method calculation. Results for electron-hydrogen scattering in the static approximation will be shown to be as accurate as a partial wave expansion with as many l's as is necessary for convergence at the incident energy being calculated.
Complex space source theory of partially coherent light wave.
Seshadri, S R
2010-07-01
The complex space source theory is used to derive a general integral expression for the vector potential that generates the extended full Gaussian wave in terms of the input value of the vector potential of the corresponding paraxial beam. The vector potential and the fields are assumed to fluctuate on a time scale that is large compared to the wave period. The Poynting vector in the propagation direction averaged over a wave period is expressed in terms of the cross-spectral density of the fluctuating vector potential across the input plane. The Schell model is assumed for the cross-spectral density. The radiation intensity distribution and the power radiated are determined. The effect of spatial coherence on the radiation intensity distribution and the radiated power are investigated for different values of the physical parameters. Illustrative numerical results are provided to bring out the effect of spatial coherence on the propagation characteristics of the fluctuating light wave.
Analysis of non linear partially standing waves from 3D velocity measurements
NASA Astrophysics Data System (ADS)
Drevard, D.; Rey, V.; Svendsen, Ib; Fraunie, P.
2003-04-01
Surface gravity waves in the ocean exhibit an energy spectrum distributed in both frequency and direction of propagation. Wave data collection is of great importance in coastal zones for engineering and scientific studies. In particular, partially standing waves measurements near coastal structures and steep or barred beaches may be a requirement, for instance for morphodynamic studies. The aim of the present study is the analysis of partially standing surface waves icluding non-linear effects. According to 1st order Stokes theory, synchronous measurements of horizontal and vertical velocity components allow calculation of rate of standing waves (Drevard et al, 2003). In the present study, it is demonstrated that for deep water conditions, partially standing 2nd order Stokes waves induced velocity field is still represented by the 1st order solution for the velocity potential contrary to the surface elevation which exhibits harmonic components. For intermediate water depth, harmonic components appear not only in the surface elevation but also in the velocity fields, but their weight remains much smaller, because of the vertical decreasing wave induced motion. For irregular waves, the influence of the spectrum width on the non-linear effects in the analysis is discussed. Keywords: Wave measurements ; reflection ; non-linear effects Acknowledgements: This work was initiated during the stay of Prof. Ib Svendsen, as invited Professor, at LSEET in autumn 2002. This study is carried out in the framework of the Scientific French National Programmes PNEC ART7 and PATOM. Their financial supports are acknowledged References: Drevard, D., Meuret, A., Rey, V. Piazzola, J. And Dolle, A.. (2002). "Partially reflected waves measurements using Acoustic Doppler Velocimeter (ADV)", Submitted to ISOPE 03, Honolulu, Hawaii, May 2003.
Properties of Baryons from Bonn-Gatchina Partial Wave Analysis
NASA Astrophysics Data System (ADS)
Sarantsev, Andrey
The recent results from the Bonn-Gatchinal partial wave analysis are reported. The analysis includes a large number of new pseudoscalar meson photoproduction data taken with polarized beam and target. The analysis also includes the information about photoproduction of vector mesons, which reveals resonant signals at masses above 2 GeV. The impact of the new data on spectrum of baryons and their properties is discussed.
Impact of plunging breaking waves on a partially submerged cube
NASA Astrophysics Data System (ADS)
Wang, A.; Ikeda, C.; Duncan, J. H.
2013-11-01
The impact of a deep-water plunging breaking wave on a partially submerged cube is studied experimentally in a tank that is 14.8 m long and 1.2 m wide with a water depth of 0.91 m. The breakers are created from dispersively focused wave packets generated by a programmable wave maker. The water surface profile in the vertical center plane of the cube is measured using a cinematic laser-induced fluorescence technique with movie frame rates ranging from 300 to 4,500 Hz. The pressure distribution on the front face of the cube is measured with 24 fast-response sensors simultaneously with the wave profile measurements. The cube is positioned vertically at three heights relative to the mean water level and horizontally at a distance from the wave maker where a strong vertical water jet is formed. The portion of the water surface between the contact point on the front face of the cube and the wave crest is fitted with a circular arc and the radius and vertical position of the fitted circle is tracked during the impact. The vertical acceleration of the contact point reaches more than 50 times the acceleration of gravity and the pressure distribution just below the free surface shows a localized high-pressure region with a very high vertical pressure gradient. This work is supported by the Office of Naval Research under grant N000141110095.
Wave interaction with a partially reflecting vertical wall protected by a submerged porous bar
NASA Astrophysics Data System (ADS)
Zhao, Yang; Liu, Yong; Li, Huajun
2016-08-01
This study gives an analytical solution for wave interaction with a partially reflecting vertical wall protected by a submerged porous bar based on linear potential theory. The whole study domain is divided into multiple sub-regions in relation to the structures. The velocity potential in each sub-region is written as a series solution by the separation of variables. A partially reflecting boundary condition is used to describe the partial reflection of a vertical wall. Unknown expansion coefficients in the series solutions are determined by matching velocity potentials among different sub-regions. The analytical solution is verified by an independently developed multi-domain boundary element method (BEM) solution and experimental data. The wave run-up and wave force on the partially reflecting vertical wall are estimated and examined, which can be effectively reduced by the submerged porous bar. The horizontal space between the vertical wall and the submerged porous bar is a key factor, which affects the sheltering function of the porous bar. The wave resonance between the porous bar and the vertical wall may disappear when the vertical wall has a low reflection coefficient. The present analytical solution may be used to determine the optimum parameters of structures at a preliminary engineering design stage.
A Potential Cost Effective Liquefaction Mitigation Countermeasure: Induced Partial Saturation
Bian Hanbing; Jia Yun; Shahrour, Isam
2008-07-08
This work is devoted to illustrate the potential liquefaction mitigation countermeasure: Induced Partial Saturation. Firstly the potential liquefaction mitigation method is briefly introduced. Then the numerical model for partially saturated sandy soil is presented. At last the dynamic responses of liquefiable free filed with different water saturation is given. It shows that the induced partial saturation is efficiency for preventing the liquefaction.
Potential changes of wave steepness and occurrence of rogue waves
NASA Astrophysics Data System (ADS)
Bitner-Gregersen, Elzbieta M.; Toffoli, Alessandro
2015-04-01
Wave steepness is an important characteristic of a sea state. It is also well established that wave steepness is one of the parameter responsible for generation of abnormal waves called also freak or rogue waves. The study investigates changes of wave steepness in the past and future wave climate in the North Atlantic. The fifth assessment report IPCC (2013) uses four scenarios for future greenhouse gas concentrations in the atmosphere called Representative Concentration Pathways (RCP). Two of these scenarios RCP 4.5 and RCP 8.5 have been selected to project future wave conditions in the North Atlantic. RCP 4.5 is believed to achieve the political target of a maximum global mean temperature increase of 2° C while RPC 8.5 is close to 'business as usual' and expected to give a temperature increase of 4° C or more. The analysis includes total sea, wind sea and swell. Potential changes of wave steepness for these wave systems are shown and compared with wave steepness derived from historical data. Three historical data sets with different wave model resolutions are used. The investigations show also changes in the mean wind direction as well as in the relative direction between wind sea and swell. Consequences of wave steepness changes for statistics of surface elevation and generation of rogue waves are demonstrated. Uncertainties associated with wave steepness projections are discussed.
MAGNETOHYDRODYNAMIC WAVES IN A PARTIALLY IONIZED FILAMENT THREAD
Soler, R.; Oliver, R.; Ballester, J. L. E-mail: ramon.oliver@uib.es
2009-07-10
Oscillations and propagating waves are commonly seen in high-resolution observations of filament threads, i.e., the fine-structures of solar filaments/prominences. Since the temperature of prominences is typically of the order of 10{sup 4} K, the prominence plasma is only partially ionized. In this paper, we study the effect of neutrals on the wave propagation in a filament thread modeled as a partially ionized homogeneous magnetic flux tube embedded in an homogeneous and fully ionized coronal plasma. Ohmic and ambipolar magnetic diffusion are considered in the basic resistive magnetohydrodynamic (MHD) equations. We numerically compute the eigenfrequencies of kink, slow, and Alfven linear MHD modes and obtain analytical approximations in some cases. We find that the existence of propagating modes is constrained by the presence of critical values of the longitudinal wavenumber. In particular, the lower and upper frequency cutoffs of kink and Alfven waves owe their existence to magnetic diffusion parallel and perpendicular to magnetic field lines, respectively. The slow mode only has a lower frequency cutoff, which is caused by perpendicular magnetic diffusion and is significantly affected by the ionization degree. In addition, ion-neutral collision is the most efficient damping mechanism for short wavelengths, while ohmic diffusion dominates in the long-wavelength regime.
Partial siamese twin as potential organ donor
Kapoor, Rakesh; Maheshwari, Ruchir; Srivastava, Aneesh; Sharma, Raj K.
2010-01-01
During evaluation of a partial Siamese twin for removal of nonviable parasitic part in an 8-year-old male child, a fully functional kidney was found. The functional status of the extra kidney was found to be within acceptable limits for the purpose of transplant, which was subsequently done in a 24-year-old patient with end-stage renal disease. The recipient is healthy 19 months after the surgery. The possibility of using organs from a partial Siamese twin makes this a unique case report. PMID:20877612
Shear Wave Generation by Decoupled and Partially Coupled Explosions
NASA Astrophysics Data System (ADS)
Baker, G. E.; Xu, H.; Stevens, J. L.
2008-12-01
Decoupling is a means of evading detection by detonation of an explosion within a large cavity, which reduces the amplitude of the seismic waves. Such explosions are however still detectable with the current global seismic network, so their discrimination is important. A fully decoupled explosion detonated in the center of a spherical cavity will be a purely compressional seismic source, and so its discrimination should be straightforward. In practice however, decoupled explosions generate S waves, often identical to and sometimes even larger (relative to P) than S waves from comparable tamped explosions. If the source were purely compressional, the S waves must be the result of conversion from P and/or Rg. Asymmetries however, such as asphericity of the cavity or offset or asymmetry of the explosion, can lead to the direct generation of S waves even from a fully decoupled explosion. Fracturing or asymmetry of the nonlinear region about the cavity of a partially decoupled explosion could also result in direct generation of S waves. Most historical decoupling data have been studied extensively, but usually with the goal of quantifying P-wave decoupling. We identify S waves in the historical records, identify observations that can be used to distinguish their genesis, and model the observations to test the proposed mechanisms. Travel times and a bubble pulse peak in the P but not S spectra of water-filled cavity explosions in salt at the Soviet Azgir test site indicate that the S is generated at the source. The observed nearfield S radiation pattern of the US decoupled explosion Sterling is matched by source modeling that includes the flat floor (due to melted and recrystallized salt) of the cavity. The similarity of the Sterling coda waveforms with distance indicates their source is at or very near the cavity. Calculations of the extent and orientation of fracturing by both the Azgir and Sterling explosions predict minimal effects on the resulting waveforms. Both
Wave Energy Potential in the Latvian EEZ
NASA Astrophysics Data System (ADS)
Beriņš, J.; Beriņš, J.; Kalnačs, J.; Kalnačs, A.
2016-06-01
The present article deals with one of the alternative forms of energy - sea wave energy potential in the Latvian Exclusice Economic Zone (EEZ). Results have been achieved using a new method - VEVPP. Calculations have been performed using the data on wave parameters over the past five years (2010-2014). We have also considered wave energy potential in the Gulf of Riga. The conclusions have been drawn on the recommended methodology for the sea wave potential and power calculations for wave-power plant pre-design stage.
Laboratory monitoring of P-waves in partially saturated sand
NASA Astrophysics Data System (ADS)
Barrière, J.; Bordes, C.; Brito, D.; Sénéchal, P.; Perroud, H.
2011-12-01
Seismic data depends on a variety of hydrogeological properties of the prospected porous media such as porosity, permeability and fluid saturation. We have performed a laboratory experiment in the kiloHertz range in order to analyze the role of partial saturation on direct propagating P-waves phase velocity and attenuation. The experiment consists of a sand-filled tank 107 cm x 34 cm x 35cm equipped with accelerometers and water capacitance probes. The P-waves seismic propagation is generated by hitting a steel ball on a granite plate on the one lateral side of the container. Several imbibition/drainage cycles are performed between the water residual saturation and the gas residual saturation. The laboratory seismic data are processed by two Continuous Wavelet Transforms using one real mother wavelet (Mexican hat) and one complex (Morlet) to recover velocity and attenuation as a function of frequency. Phase velocity of direct P-wave decreases with an increase of water content and is quite consistent with the low frequency limit of the Biot's theory both for imbibition and drainage. The interpretation of the P-waves attenuation needs to go beyond the macroscopic fluid flow of Biot's theory and to introduce a viscoelastic contribution linked to the grain to grain overall losses which are described by a constant Q-model. A strong hysteresis between imbibition and drainage is observed and explained by introducing an effective permeability depending on water and gas relative permeabilities (Van Genuchten model).
A New Pion-Nucleon Partial Wave Analysis
NASA Astrophysics Data System (ADS)
Sadler, Michael; Watson, Shon; Stahov, Jugoslav
2006-10-01
Existing determinations of the masses, widths and decay modes of low-lying excited states of the nucleon, as compiled in the Review of Particle Physics, are determined from energy-independent partial wave analyses of pion-nucleon scattering data. For the N*(1440) and most other resonances under 2 GeV, the analyses cited are the Karlsruhe-Helsinki, Carnegie Mellon-Berkeley and Kent State analyses, the latter of which used the elastic amplitudes from the other two. The data included in these analyses were published before 1980. Other analyses, notably the recent ones from George Washington University and the Pittsburgh-Argonne group, are ``not used for averages, fits, limits, etc.'' Complete sets of measurements (differential cross sections, analyzing powers and spin rotation parameters) have been measured in the N*(1440) resonance region since 1980, culminating in the Crystal Ball program at BNL to measure all-neutral final states (charge exchange, multiple pi-zero final states, and inverse photoproduction). A new partial wave analysis of the Karlsruhe-Helsinki type has been started by Abilene Christian University, University of Tuzla, and Rudjer Boskovic Institute. The analysis is constrained by fixed-t and interior hyperbolic dispersion relations. Comparisons of the new analysis to modern experimental data and to previous analyses will be presented.
Treatment of Ion-Atom Collisions Using a Partial-Wave Expansion of the Projectile Wavefunction
ERIC Educational Resources Information Center
Wong, T. G.; Foster, M.; Colgan, J.; Madison, D. H.
2009-01-01
We present calculations of ion-atom collisions using a partial-wave expansion of the projectile wavefunction. Most calculations of ion-atom collisions have typically used classical or plane-wave approximations for the projectile wavefunction, since partial-wave expansions are expected to require prohibitively large numbers of terms to converge…
Treatment of Ion-Atom Collisions Using a Partial-Wave Expansion of the Projectile Wavefunction
ERIC Educational Resources Information Center
Wong, T. G.; Foster, M.; Colgan, J.; Madison, D. H.
2009-01-01
We present calculations of ion-atom collisions using a partial-wave expansion of the projectile wavefunction. Most calculations of ion-atom collisions have typically used classical or plane-wave approximations for the projectile wavefunction, since partial-wave expansions are expected to require prohibitively large numbers of terms to converge…
Search for Higher Flavor Multiplets in Partial Wave Analyses
Yakov Azimov; Richard Arndt; I.I. Strakovsky; Ron Workman; K. Goeke
2005-04-01
The possible existence of higher multi-quark flavor multiplets of baryons is investigated. We argue that the S-matrix should have poles with any quantum numbers, including those which are exotic. This argument provides a novel justification for the existence of hadrons with arbitrary exotic structure. Though it does not constitute a proof, there are still no theoretical arguments against exotics. We then consider KN and piN scattering. Conventional and modified partial-wave analyses provide several sets of candidates for correlated pairs (Theta1, Delta), each of which could label a related 27-plet. Properties of the pairs (masses, mass orderings, spin-parity quantum numbers) do not quite correspond to the current theoretical expectations. Decay widths of the candidates are either wider or narrower than expected. Possible reasons for such disagreements are briefly discussed.
Baryon Spectroscopy Through Partial-Wave Analysis and Meson Photoproduction
Manley, D. Mark
2016-09-08
The principal goal of this project is the experimental and phenomenological study of baryon spectroscopy. The PI's group consists of himself and three graduate students. This final report summarizes research activities by the PI's group during the period 03/01/2015 to 08/14/2016. During this period, the PI co-authored 11 published journal papers and one proceedings article and presented three invited talks. The PI's general interest is the investigation of the baryon resonance spectrum up to masses of ~ 2 GeV. More detail is given on two research projects: Neutral Kaon Photoproduction and Partial-Wave Analyses of γp → η p, γn → η n, and γp → K⁺ Λ.
NASA Astrophysics Data System (ADS)
Li, Jia; Wu, Pinghui; Chang, Liping
2016-02-01
Within the first-order Born approximation, the spectrum of light generated by the scattering of a partially coherent wave from a quasi-homogeneous (QH) medium is derived. In particular, the partially coherent incident wave is produced by Young's pinholes. It is shown that the spectrum of the scattered field is identical to the spectrum of incident plane waves if the Fourier transform of the normalized correlation coefficient (NCC) of the scattering potential satisfies a certain scaling law. The scaling law is valid when the medium size is sufficiently small compared with the space between Young' pinholes. Furthermore, comparisons are made between our conditions with the previous results.
Deuteron wave function and OPE potential
NASA Astrophysics Data System (ADS)
Righi, S.; Rosa-Clot, M.
1987-06-01
The deuteron wave function is calculated integrating from outside the Schredinger equation using as input its asymptotic behaviour. Some potentials are tested and the one pion exchange potential (OPEP) is shown to be the main responsible of the wave function structure up to distances of about 1 fm. The relevance of the short range part of the potential is analyzed and it is shown that a substantial enhancement of the OPEP central part is needed in the deuteron channel.
Mechanical surface waves accompany action potential propagation
NASA Astrophysics Data System (ADS)
El Hady, Ahmed; Machta, Benjamin B.
2015-03-01
Many diverse studies have shown that a mechanical displacement of the axonal membrane accompanies the electrical pulse defining the action potential (AP). We present a model for these mechanical displacements as arising from the driving of surface wave modes in which potential energy is stored in elastic properties of the neuronal membrane and cytoskeleton while kinetic energy is carried by the axoplasmic fluid. In our model, these surface waves are driven by the travelling wave of electrical depolarization characterizing the AP, altering compressive electrostatic forces across the membrane. This driving leads to co-propagating mechanical displacements, which we term Action Waves (AWs). Our model allows us to estimate the shape of the AW that accompanies any travelling wave of voltage, making predictions that are in agreement with results from several experimental systems. Our model can serve as a framework for understanding the physical origins and possible functional roles of these AWs.
Wave power potential in Malaysian territorial waters
NASA Astrophysics Data System (ADS)
Asmida Mohd Nasir, Nor; Maulud, Khairul Nizam Abdul
2016-06-01
Up until today, Malaysia has used renewable energy technology such as biomass, solar and hydro energy for power generation and co-generation in palm oil industries and also for the generation of electricity, yet, we are still far behind other countries which have started to optimize waves for similar production. Wave power is a renewable energy (RE) transported by ocean waves. It is very eco-friendly and is easily reachable. This paper presents an assessment of wave power potential in Malaysian territorial waters including waters of Sabah and Sarawak. In this research, data from Malaysia Meteorology Department (MetMalaysia) is used and is supported by a satellite imaginary obtained from National Aeronautics and Space Administration (NASA) and Malaysia Remote Sensing Agency (ARSM) within the time range of the year 1992 until 2007. There were two types of analyses conducted which were mask analysis and comparative analysis. Mask analysis of a research area is the analysis conducted to filter restricted and sensitive areas. Meanwhile, comparative analysis is an analysis conducted to determine the most potential area for wave power generation. Four comparative analyses which have been carried out were wave power analysis, comparative analysis of wave energy power with the sea topography, hot-spot area analysis and comparative analysis of wave energy with the wind speed. These four analyses underwent clipping processes using Geographic Information System (GIS) to obtain the final result. At the end of this research, the most suitable area to develop a wave energy converter was found, which is in the waters of Terengganu and Sarawak. Besides that, it was concluded that the average potential energy that can be generated in Malaysian territorial waters is between 2.8kW/m to 8.6kW/m.
Potential surface waves in anisotropic plasma
Aliev, Yu. M. Vagin, K. Yu. Uryupin, S. A.; Frolov, A. A.
2016-06-15
The dependences of the frequency and damping rate of a potential surface wave on the wavenumber and the degree of anisotropy of a bi-Maxwellian electron distribution characterized by different temperatures along and across the plasma surface are established. It is demonstrated that the influence of electron thermal motion along the plasma surface on the surface wave properties is similar to the influence of thermal motion on the properties of a bulk Langmuir wave. On the contrary, thermal motion across the surface qualitatively affects the dispersion relation and substantially increases the damping rate.
H-He elastic scattering at low energies: Contribution of nonzero partial waves
Sinha, Prabal K.; Ghosh, A.S.
2005-01-01
The present study reports the nonzero partial wave elastic cross sections together with s-wave results for the scattering of an antihydrogen atom off a gaseous helium target at thermal energies (up to 10{sup -2} a.u.). We have used a nonadiabatic atomic orbital method having different basis sets to investigate the system. The consideration of all the significant partial waves (up to J=24) reduces the oscillatory nature present in the individual partial wave cross section. The added elastic cross section is almost constant up to 10{sup -7} a.u. and then decreases steadily and very slowly with increasing energy.
Ferromagnetic transition in harmonically trapped Fermi gas with higher partial-wave interactions
NASA Astrophysics Data System (ADS)
Sun, Zongli; Gu, Qiang
2017-01-01
Spontaneous ferromagnetic transition in trapped Fermi gas is studied in the presence of a higher partial-wave interaction. At the mean-field level, the ground-state energy contribution from an arbitrary partial wave is derived, with which the equilibrium density profile of each spin component can be calculated. Our results show that, in the spin-\\tfrac{1}{2} Fermi gas, the individual repulsive d-wave interaction can induce ferromagnetic transition; while the individual repulsive or attractive p- and f-wave interactions fail. In addition, the higher partial waves can have a remarkable influence on the ferromagnetic phase induced by the s-wave interaction. The repulsive d-wave interaction and attractive p- or f-wave interactions lower the s-wave Stoner point and critical particle number, while the attractive d-wave interaction and repulsive p- or f-wave interactions increase them. In addition, our results also show that both repulsive d-wave interaction and attractive p- or f-wave interactions can enhance the ferromagnetic state induced by s-wave interaction.
Raman three-wave interaction in partially spin polarized plasma
NASA Astrophysics Data System (ADS)
Shahid, M.; Iqbal, Z.; Jamil, M.; Murtaza, G.
2017-10-01
By employing the separate spin evolution-quantum hydrodynamic model (SSE-QHD), the nonlinear growth rate of the parametric decay instability is studied via the Raman scattering process of three-wave coupling. SSE-QHD equations are solved for the pump wave (O-mode), sideband Shear Alfvén wave, and the electron plasma perturbations. It is observed that the spectrum of the electron plasma waves is modified due to newly generated spin dependent waves which contribute in the coupling process. The nonlinear growth rate as a result of three wave coupling is plotted for different sets of parameters and conditions. It is also observed that the growth rate is suppressed due to the spin effects. Shifting of diamagnetic behavior of plasma to paramagnetic behavior is noticed.
Wave Directional Characteristics on a Partially Sheltered Coast.
1982-01-01
California Sea Grant Program, IMR Ref. 78-102. Pawka, S. S., V. Hsiao, 0. H. Shemdin , and D. L. Inman, 1978, "Comparison of wave directional spectra...Pawka, S. S., S. V. Hsiao, 0. H. Shemdin , and D. L. Inman, 1980, "Com- parisons between wave directional spectra from SAR and pressure sensor arrays...effects of wave induced airflow, are under 77 active investigation (Evans and Shemdin ,1980). Previous ground truth experiments, reported in Mcleish et al
Mechanical Surface Waves Accompany Action Potential Propagation
NASA Astrophysics Data System (ADS)
Machta, Benjamin; El Hady, Ahmed
2015-03-01
The action potential (AP) is the basic mechanism by which information is transmitted along neuronal axons. Although the excitable nature of axons is understood to be primarily electrical, many experimental studies have shown that a mechanical displacement of the axonal membrane co-propagates with the electrical signal. While the experimental evidence for co-propagating mechanical waves is diverse and compelling, there is no consensus for their physical underpinnings. We present a model in which these mechanical displacements arise from the driving of mechanical surface waves, in which potential energy is stored in elastic deformations of the neuronal membrane and cytoskeleton while kinetic energy is stored in the movement of the axoplasmic fluid. In our model these surface waves are driven by the traveling wave of electrical depolarization that characterizes the AP, altering the electrostatic forces across the membrane as it passes. Our model allows us to predict the shape of the displacement that should accompany any traveling wave of voltage, including the well-characterized AP. We expect our model to serve as a framework for understanding the physical origins and possible functional roles of these AWs in neurobiology. See Arxiv/1407.7600
Analytical expressions for partial wave two-body Coulomb transition matrices at ground-state energy
NASA Astrophysics Data System (ADS)
Kharchenko, V. F.
2016-11-01
Leaning upon the Fock method of the stereographic projection of the three-dimensional momentum space onto the four-dimensional unit sphere the possibility of the analytical solving of the Lippmann-Schwinger integral equation for the partial wave two-body Coulomb transition matrix at the ground bound state energy has been studied. In this case new expressions for the partial p-, d- and f-wave two-body Coulomb transition matrices have been obtained in the simple analytical form. The developed approach can also be extended to determine analytically the partial wave Coulomb transition matrices at the energies of excited bound states.
Partial wave decomposition in Friedrichs model with self-interacting continua
NASA Astrophysics Data System (ADS)
Xiao, Zhiguang; Zhou, Zhi-Yong
2017-07-01
We consider the nonrelativistic model of coupling bare discrete states with continuum states in which the continuum states can have interactions among themselves. By partial-wave decomposition and constraint to the conserved angular momentum eigenstates, the model can be reduced to Friedrichs-like model with additional interactions between the continua. If a kind of factorizable form factor is chosen, the model can be exactly solvable, that is, the generalized discrete eigenstates including bound states, virtual states, and resonances can all be represented using the original bare states, and so do the in-state and out-state. The exact S matrix is thus obtained. We then discuss the behaviors of the dynamically generated S-wave and P-wave discrete states as the coupling is varying when there is only one self-interacting bare continuum state. We find that even when the potential is repulsive there could also be resonances and virtual states. In the P-wave cases with attractive interaction, we find that when there is a near-threshold bound state, there will always be an accompanying virtual state and we also give a more general argument of this effect.
Pseudo Rayleigh wave in a partially saturated non-dissipative porous solid
NASA Astrophysics Data System (ADS)
Sharma, M. D.
2017-03-01
Propagation of surface waves is studied at the pervious boundary of a porous solid saturated with a mixture of two immiscible fluids. An approach, based on continuum mixture theory, is used to derive a secular equation for the propagation of harmonic waves at the stress-free plane surface of this non-dissipative medium. Numerical analysis shows that this secular equation may not represent the propagation of true surface wave in the porous aggregate. Then, this equation is solved numerically for the propagation of pseudo Rayleigh wave or the leaky surface waves. To ensure the existence of pseudo Rayleigh wave, capillary effect between two (wetting and non-wetting) pore-fluids is related to the partial saturation. Effects of porosity and partial saturation coupled with capillary effect are observed on the phase velocity of pseudo Rayleigh waves in sandstone saturated with water-CO2 mixture.
Development of Partial-Charge Potential for GaN
Gao, Fei; Devanathan, Ram; Oda, Takuji; Weber, William J.
2006-09-01
Partial-charged potentials for GaN are systematically developed that describes a wide range of structural properties, where the reference data for fitting the potential parameters are taken from ab initial calculations or experiments. The present potential model provides a good fit to different structural geometries and high pressure phases of GaN. The high-pressure transition from wurtzite to rock-salt structure is correctly described yielding the phase transition pressure of about 55 GPa, and the calculated volume change at the transition is in good agreement with experimental data. The results are compared with those obtained by ab initio simulations.
Workman, R. L.; Tiator, L.; Wunderlich, Y.; ...
2017-01-19
Here, we compare the methods of amplitude reconstruction, for a complete experiment and a truncated partial-wave analysis, applied to the photoproduction of pseudoscalar mesons. The approach is pedagogical, showing in detail how the amplitude reconstruction (observables measured at a single energy and angle) is related to a truncated partial-wave analysis (observables measured at a single energy and a number of angles).
SAID Partial Wave Analyses from CNS DAC (Center for Nuclear Studies Data Analysis Center)
George Washington University (GW) has one of the largest university-based nuclear-physics groups in the nation. Many of the current and future projects are geared to Thomas Jefferson National Accelerator Facility (JLab) at Newport News, VA. JLab is the world's premier electron accelerator for nuclear physics, and GW is one of the charter members of the governing body of JLab, the Southeastern Universities Research Association (SURA). The George Washington Data Analysis Center (DAC) was created in 1998 by an agreement among the Department of Energy, Jefferson Lab, and the GW Center for Nuclear Studies.The activities of the DAC fall into four distinct categories: 1) Performing partial-wave analyses of fundamental two- and three-body reactions; 2) Maintenance of databases associated with these reactions; 3) Development of software to disseminate DAC results (as well as the results of competing model-independent analyses and potential approaches); and 4) Phenomenological and theoretical investigations which bridge the gap between theory and experiment; in particular, the extraction of N* and D * hadronic and electromagnetic couplings. Partial Wave Analyses (and the associated databases) available at GW are: Pion-Nucleon, Kaon-Nucleon, Nucleon-Nucleon, Pion Photoproduction, Pion Electroproduction, Kaon Photoproduction, Eta Photoproduction, Eta-Prime Photoproduction, Pion-Deuteron (elastic), and Pion-Deuteron to Proton+Proton. [Taken from http://www.gwu.edu/~ndl/dac.htm">http://www.gwu.edu/~ndl/dac.htm
Partial reflections of radio waves from the lower ionosphere
NASA Technical Reports Server (NTRS)
Connolly, D. J.; Tanenbaum, S. B.
1972-01-01
The addition of phase difference measurements to partial reflection experiments is discussed, and some advantages of measuring electron density this way are pointed out. The additional information obtained reduces the requirement for an accurate predetermination of collision frequency. Calculations are also made to estimate the errors expected in partial-reflection experiments due to the assumption of Fresnel reflection and to the neglect of coupling between modes. In both cases, the errors are found to be of the same order as known errors in the measurements due to current instrumental limitations.
Extracting scattering phase shifts in higher partial waves from lattice QCD calculations
Luu, Thomas; Savage, Martin J.
2011-06-01
Lüscher’s method is routinely used to determine meson-meson, meson-baryon, and baryon-baryon s-wave scattering amplitudes below inelastic thresholds from lattice QCD calculations—presently at unphysical light-quark masses. In this work we review the formalism and develop the requisite expressions to extract phase shifts describing meson-meson scattering in partial waves with angular momentum l≤6 and l=9. The implications of the underlying cubic symmetry, and strategies for extracting the phase shifts from lattice QCD calculations, are presented, along with a discussion of the signal-to-noise problem that afflicts the higher partial waves.
Treatment of ion-atom collisions using a partial-wave expansion of the projectile wavefunction
Foster, M; Colgan, J; Wong, T G; Madison, D H
2008-01-01
We present calculations of ion-atom collisions using a partial-wave expansion of the projectile wavefunction. Most calculations of ion-atom collisions have typically used classical or plane-wave approximations for the projectile wavefunction, since partial-wave expansions are expected to require prohibitively large numbers of terms to converge scattering quantities. Here we show that such calculations are possible using modern high-performance computing. We demonstrate the utility of our method by examining elastic scattering of protons by hydrogen and helium atoms, problems familiar to undergraduate students of atomic scattering. Application to ionization of helium using partial-wave expansions of the projectile wavefunction, which has long been desirable in heavy-ion collision physics, is thus quite feasible.
Shock-wave structure in a partially ionized gas
NASA Technical Reports Server (NTRS)
Lu, C. S.; Huang, A. B.
1974-01-01
The structure of a steady plane shock in a partially ionized gas has been investigated using the Boltzmann equation with a kinetic model as the governing equation and the discrete ordinate method as a tool. The effects of the electric field induced by the charge separation on the shock structure have also been studied. Although the three species of an ionized gas travel with approximately the same macroscopic velocity, the individual distribution functions are found to be very different. In a strong shock the atom distribution function may have double peaks, while the ion distribution function has only one peak. Electrons are heated up much earlier than ions and atoms in a partially ionized gas. Because the interactions of electrons with atoms and with ions are different, the ion temperature can be different from the atom temperature.
Transition metal partially supported graphene: Magnetism and oscillatory electrostatic potentials
Liu, Xiaojie; Wang, Cai-Zhuang
2017-08-07
Using first-principles calculations here, we show that Mn and Cr layers under graphene exhibit almost zero magnetic moment due to anti-ferromagnetic order, while ferromagnetic coupling in Fe, Co, and Ni leads to large magnetic moment. The transition metal partially supported graphene, with a mixture of supported and pristine areas, exhibits an oscillatory electrostatic potential, thus alternating the electric field across the supported and pristine areas. Such an effect can be utilized to control mass transport and nanostructure self-organization on graphene at the atomic level.
Transition metal partially supported graphene: Magnetism and oscillatory electrostatic potentials
NASA Astrophysics Data System (ADS)
Liu, Xiaojie; Wang, Cai-Zhuang
2017-08-01
Using first-principles calculations, we show that Mn and Cr layers under graphene exhibit almost zero magnetic moment due to anti-ferromagnetic order, while ferromagnetic coupling in Fe, Co, and Ni leads to large magnetic moment. Transition metal partially supported graphene, with a mixture of supported and pristine areas, exhibits an oscillatory electrostatic potential, thus alternating the electric field across the supported and pristine areas. Such an effect can be utilized to control mass transport and nanostructure self-organization on graphene at the atomic level.
Broadening the potential bandwidth of piezoelectric transducers by partial depolarization
Hariti, Sid Ahmed; Hole, Stephane; Lewiner, Jacques
2001-06-18
Elastic waves are used more and more in a nondestructive way to probe the physical properties of materials. The resolution of the images or the accuracy of the measurements is directly associated with the ultrasonic signal bandwidth and amplitude a system can generate or detect. The authors propose a technique to broaden the potential bandwidth of piezoelectric generators and sensors, which is based on utilizing a nonuniformly-polarized piezoelectric material. Both simulated and experimental responses are shown. They are in good agreement and exhibit a useful bandwidth over several natural harmonics of the piezoelectric transducer. {copyright} 2001 American Institute of Physics.
Evaluation of partial widths and branching ratios from resonance wave functions
Goldzak, Tamar; Gilary, Ido; Moiseyev, Nimrod
2010-11-15
A quantum system in a given resonance state has different open channels for decay. Partial widths are the decay rates of the resonance (metastable) state into the different open channels. Here we present a rigorous derivation of the partial widths from the solution of a time-dependent Schroedinger equation with outgoing boundary conditions. We show that the sum of the partial widths obtained from the resonance wave function is equal to the total width. The difference with respect to previous studies on partial widths and branching ratios is discussed.
NASA Technical Reports Server (NTRS)
Shertzer, Janine; Temkin, Aaron
2007-01-01
In the first two papers in this series, we developed a method for studying electron-hydrogen scattering that does not use partial wave analysis. We constructed an ansatz for the wave function in both the static and static exchange approximations and calculated the full scattering amplitude. Here we go beyond the static exchange approximation, and include correlation in the wave function via a modified polarized orbital. This correlation function provides a significant improvement over the static exchange approximation: the resultant elastic scattering amplitudes are in very good agreement with fully converged partial wave calculations for electron-hydrogen scattering. A fully variational modification of this approach is discussed in the conclusion of the article Popular summary of Direct calculation of the scattering amplitude without partial wave expansion. III ....." by J. Shertzer and A. Temkin. In this paper we continue the development of In this paper we continue the development of a new approach to the way in which researchers have traditionally used to calculate the scattering cross section of (low-energy) electrons from atoms. The basic mathematical problem is to solve the Schroedinger Equation (SE) corresponding the above physical process. Traditionally it was always the case that the SE was reduced to a sequence of one-dimensional (ordinary) differential equations - called partial waves which were solved and from the solutions "phase shifts" were extracted, from which the scattering cross section was calculated.
New results on the Roper resonance and the P11 partial wave
NASA Astrophysics Data System (ADS)
Sarantsev, A. V.; Fuchs, M.; Kotulla, M.; Thoma, U.; Ahrens, J.; Annand, J. R. M.; Anisovich, A. V.; Anton, G.; Bantes, R.; Bartholomy, O.; Beck, R.; Beloglazov, Yu.; Castelijns, R.; Crede, V.; Ehmanns, A.; Ernst, J.; Fabry, I.; Flemming, H.; Fösel, A.; Funke, Chr.; Gothe, R.; Gridnev, A.; Gutz, E.; Höffgen, St.; Horn, I.; Hößl, J.; Hornidge, D.; Janssen, S.; Junkersfeld, J.; Kalinowsky, H.; Klein, F.; Klempt, E.; Koch, H.; Konrad, M.; Kopf, B.; Krusche, B.; Langheinrich, J.; Löhner, H.; Lopatin, I.; Lotz, J.; McGeorge, J. C.; MacGregor, I. J. D.; Matthäy, H.; Menze, D.; Messchendorp, J. G.; Metag, V.; Nikonov, V. A.; Novinski, D.; Novotny, R.; Ostrick, M.; van Pee, H.; Pfeiffer, M.; Radkov, A.; Rosner, G.; Rost, M.; Schmidt, C.; Schoch, B.; Suft, G.; Sumachev, V.; Szczepanek, T.; Walther, D.; Watts, D. P.; Weinheimer, Chr.; CB-ELSA; A2-TAPS Collaborations
2008-01-01
Properties of the Roper resonance, the first scalar excitation of the nucleon, are determined. Pole positions and residues of the P11 partial wave are studied in a combined analysis of pion- and photo-induced reactions. We find the Roper pole at { (1371 ± 7) - i (92 ± 10) } MeV and an elasticity of 0.61 ± 0.03. The largest decay coupling is found for the Nσ (σ = (ππ)-S-wave). The analysis is based on new data on γp → pπ0π0 for photons in the energy range from the two-pion threshold to 820 MeV from TAPS at Mainz and from 0.4 to 1.3 GeV from Crystal Barrel at Bonn and includes further data from other experiments. The partial wave analysis excludes the possibility that the Roper resonance is split into two states with different partial decay widths.
New results on the Roper resonance and the P partial wave
NASA Astrophysics Data System (ADS)
Cb-Elsa; A2-Taps Collaborations; Sarantsev, A. V.; Fuchs, M.; Kotulla, M.; Thoma, U.; Ahrens, J.; Annand, J. R. M.; Anisovich, A. V.; Anton, G.; Bantes, R.; Bartholomy, O.; Beck, R.; Beloglazov, Yu.; Castelijns, R.; Crede, V.; Ehmanns, A.; Ernst, J.; Fabry, I.; Flemming, H.; Fösel, A.; Funke, Chr.; Gothe, R.; Gridnev, A.; Gutz, E.; Höffgen, St.; Horn, I.; Hößl, J.; Hornidge, D.; Janssen, S.; Junkersfeld, J.; Kalinowsky, H.; Klein, F.; Klempt, E.; Koch, H.; Konrad, M.; Kopf, B.; Krusche, B.; Langheinrich, J.; Löhner, H.; Lopatin, I.; Lotz, J.; McGeorge, J. C.; MacGregor, I. J. D.; Matthäy, H.; Menze, D.; Messchendorp, J. G.; Metag, V.; Nikonov, V. A.; Novinski, D.; Novotny, R.; Ostrick, M.; van Pee, H.; Pfeiffer, M.; Radkov, A.; Rosner, G.; Rost, M.; Schmidt, C.; Schoch, B.; Suft, G.; Sumachev, V.; Szczepanek, T.; Walther, D.; Watts, D. P.; Weinheimer, Chr.
2008-01-01
Properties of the Roper resonance, the first scalar excitation of the nucleon, are determined. Pole positions and residues of the P partial wave are studied in a combined analysis of pion- and photo-induced reactions. We find the Roper pole at {(1371±7)-i(92±10)} MeV and an elasticity of 0.61±0.03. The largest decay coupling is found for the Nσ (σ=(ππ)-S-wave). The analysis is based on new data on γp→pππ for photons in the energy range from the two-pion threshold to 820 MeV from TAPS at Mainz and from 0.4 to 1.3 GeV from Crystal Barrel at Bonn and includes further data from other experiments. The partial wave analysis excludes the possibility that the Roper resonance is split into two states with different partial decay widths.
On the partial wave method for self energy calculations for non-hydrogenic electrons
NASA Astrophysics Data System (ADS)
Hagelstein, Peter L.
1994-07-01
A method for computing the self-energy correction for highly-ionized and high-Z many electron atoms is proposed and developed. The method is based on a partical wave analysis, and is immediately applicable to general potentials and many-electron wavefunctions. In this work we discuss the general approach, develop a formalism amenable to practical anal- ysis, provide the angular momentum reduction for arbitrary one-electron orbitals, and describe the computation of the twdimensional integrals and their kernels required for the partial wave analysis. Analytical results allowing for a practical renormalization scheme are discussed. This work is exploratory and developmental, and the present document provides a status report of our eforts. To date we have obtained numerical evidence that the method successfully handles the renormalization, and we report on significant progress in numerical methods for evaluating and approximating the two-dimensional integrals which occur in the method. We believe that this method can ultimately achieve an accuracy which is competitive with that of modern Brown's method calculations. The methods discussed within this work for approximating the two-dimensional radial matrix eIements including the full retarded couIomb interaction can be applied to other relativistic atomic physics calculations as a practical way to obtain improvements over the coulomb and Breit approximations.
NASA Technical Reports Server (NTRS)
Shertzer, Janine; Temkin, Aaron
2004-01-01
The development of a practical method of accurately calculating the full scattering amplitude, without making a partial wave decomposition is continued. The method is developed in the context of electron-hydrogen scattering, and here exchange is dealt with by considering e-H scattering in the static exchange approximation. The Schroedinger equation in this approximation can be simplified to a set of coupled integro-differential equations. The equations are solved numerically for the full scattering wave function. The scattering amplitude can most accurately be calculated from an integral expression for the amplitude; that integral can be formally simplified, and then evaluated using the numerically determined wave function. The results are essentially identical to converged partial wave results.
NASA Technical Reports Server (NTRS)
Shertzer, Janine; Temkin, Aaron
2004-01-01
The development of a practical method of accurately calculating the full scattering amplitude, without making a partial wave decomposition is continued. The method is developed in the context of electron-hydrogen scattering, and here exchange is dealt with by considering e-H scattering in the static exchange approximation. The Schroedinger equation in this approximation can be simplified to a set of coupled integro-differential equations. The equations are solved numerically for the full scattering wave function. The scattering amplitude can most accurately be calculated from an integral expression for the amplitude; that integral can be formally simplified, and then evaluated using the numerically determined wave function. The results are essentially identical to converged partial wave results.
Partial-wave analysis of nucleon-nucleon elastic scattering data
NASA Astrophysics Data System (ADS)
Workman, Ron L.; Briscoe, William J.; Strakovsky, Igor I.
2016-12-01
Energy-dependent and single-energy fits to the existing nucleon-nucleon database have been updated to incorporate recent measurements. The fits cover a region from threshold to 3 GeV, in the laboratory kinetic energy, for proton-proton scattering, with an upper limit of 1.3 GeV for neutron-proton scattering. Experiments carried out at the COSY-WASA and COSY-ANKE facilities have had a significant impact on the partial-wave solutions. Results are discussed in terms of both partial-wave and direct reconstruction amplitudes.
Twisted partially coherent bosonic matter wave and its orbital angular momentum
NASA Astrophysics Data System (ADS)
Chen, Jun; Chen, Xiang-yun; Lin, Qiang
2017-06-01
Orbital angular momentum (OAM) is a general characteristic of coherent bosonic matter waves. Partially coherent bosonic matter waves (PCMWs) can also have OAM according to a vortex or twisted structure of the correlation phase of the first-order correlation function. We theoretically prove that a twist phase exists under partial coherence, and this phase contributes to the OAM flux of the PCMW field. We also present an example which illustrates that a twist phase can be produced by illuminating a Gaussian Schell model cold atomic cloud with a sequence of cylindrical lens pulses.
NASA Astrophysics Data System (ADS)
Kupershtokh, A. L.; Karpov, D. I.
2016-10-01
A stochastic model of partial discharges inside gas inclusions in condensed dielectrics was developed. The possibility of a "relay-race" wave propagation mechanism of partial discharges in a linear chain of gas inclusions is shown. The lattice Boltzmann method is successfully implemented for three-dimensional computer simulations of flows of dielectric fluid with bubbles. Growth and elongation of bubbles in a liquid dielectric under the action of a strong electric field are simulated. The physical model of propagation of partial discharges along a chain of gas bubbles in a liquid is formulated.
Attenuation measurements of ultrasonic P-wave and S-wave in partially frozen unconsolidated sands
NASA Astrophysics Data System (ADS)
Matsushima, J.; Suzuki, M.; Kato, Y.; Rokugawa, S.; Kato, A.
2012-12-01
Seismic attenuation which controls both the amplitude decay of seismic waves and the accompanying frequency change is a signature of the wave-rock interaction. Seismic attenuation in rocks is a highly variable parameter, which depends on the confining pressure, porosity, degree of fluid saturation, and fluid type. Although seismic attenuation has been widely used to estimate physical conditions and rock properties in various fields, the loss mechanisms responsible for seismic attenuation often are unclear and controversial. To elucidate a plausible mechanism for seismic attenuation, the joint use of both P- and S-waves will provide more helpful information because these two types of waves respond differently to fluid and solid combinations. We have conducted ultrasonic P- and S-wave transmission measurements to examine the influence of ice-brine coexisting system grown in the pore space of unconsolidated sands on ultrasonic P- and S-waves. We observed the variations of a transmitted wave with a frequency content of 100-1000 kHz , changing its temperature from 20°C to -15°C. We use not only impulse-type signals but also sweep-type signals to prevent from the spectral leakage effect caused by the effect of windowing. We concern with attenuation at ultrasonic frequencies of 500-1000 kHz for P-waves and 100-400 kHz for S-waves. Our observation of the variation of the Poisson's ratio and the ratio of P- to S-wave attenuation with changing temperature indicates the possibilities of the joint use of both P- and S-waves to elucidate a plausible mechanism for seismic attenuation.
Nuclear pairing from microscopic forces: Singlet channels and higher-partial waves
NASA Astrophysics Data System (ADS)
Maurizio, Stefano; Holt, Jeremy W.; Finelli, Paolo
2014-10-01
Background: An accurate description of nuclear pairing gaps is extremely important for understanding static and dynamic properties of the inner crusts of neutron stars and to explain their cooling process. Purpose: We plan to study the behavior of the pairing gaps ΔF as a function of the Fermi momentum kF for neutron and nuclear matter in all relevant angular momentum channels where superfluidity is believed to naturally emerge. The calculations will employ realistic chiral nucleon-nucleon potentials with the inclusion of three-body forces and self-energy effects. Methods: The superfluid states of neutron and nuclear matter are studied by solving the BCS gap equation for chiral nuclear potentials using the method suggested by Khodel et al., where the original gap equation is replaced by a coupled set of equations for the dimensionless gap function χ (k) defined by Δ(k )=ΔFχ(k) and a nonlinear algebraic equation for the gap magnitude ΔF=Δ(kF) at the Fermi surface. This method is numerically stable even for small pairing gaps, such as that encountered in the coupled 3PF2 partial wave. Results: We have successfully applied Khodel's method to singlet (S) and coupled channel (SD and PF) cases in neutron and nuclear matter. Our calculations agree with other ab initio approaches, where available, and provide crucial inputs for future applications in superfluid systems.
Extension of the Temkin-Poet model to L>0 partial waves: The generalized exchange approximation
NASA Astrophysics Data System (ADS)
Temkin, A.; Shertzer, J.; Bhatia, A. K.
1998-02-01
The Temkin-Poet (TP) model of electron-hydrogen scattering is here generalized to L>0 partial waves in such a way as to be a clear generalization of the exchange approximation (EA). This generalized exchange approximation (GEA) leads to a pair of coupled partial differential equations (PDE's). Boundary conditions are formulated, and the PDE's are solved by a finite element method program adapted from a previous partial wave calculation of the full problem [Shertzer and Botero, Phys. Rev. A 49, 3673 (1994)]. Calculations are carried out for 1,3P and 1,3D partial waves in the elastic region. Phase shifts are bounded from below, as is rigorously required, by exchange approximate phase shifts. But the GEA can yield resonances: in the elastic region, in addition to the 1S resonance of the TP model, there is a 3P resonance whose position and width are in close proximity to the lowest 3P resonance of the full theory. The GEA distinguishes between singlet and triplet scattering for all L, and it contains inelastic and ionization channels in the appropriate energy regions. It is expected that the GEA will have its greatest utility in the ionization domain, as a nontrivial test of the many recent methods being developed.
NASA Astrophysics Data System (ADS)
Pradhan, O.; Matsushima, J.; Suzuki, M.
2012-12-01
Methane hydrate bearing sediment possesses unique seismic wave propagation properties. Both high seismic wave velocity and high wave attenuation are observed in methane hydrate bearing sediment. We used brine with salinity 2% in analogous to methane hydrate for conducting laboratory waveform measurement and characterization by using nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) technique. When brine undergoes freezing, only pure water freezes into ice and salt remains in solution with successively increasing salinity and decreasing freezing point of the solution. Unfrozen brine is enclosed inside micro pores in ice, with exhibiting solid-liquid coexisting system. We used conventional pulse transmission technique to measure compressional wave velocity in partially frozen brine when brine is subjected cooling down to -12oC. Waveform measurement shows sudden increase in compressional wave velocity at temperature -3oC. Below -3oC, velocity increases slightly. Largest wave attenuation is observed at around -3oC. We conducted MRI experiment by using instrument Varian Unity Inova 4.7T. T1 weighted and diffusion weighted (DW) MR images were prepared by applying magnetic field gradient of 0.3 gauss/cm. We observe the spatial distribution of pores, microstructures and heterogeneity in partially frozen brine sample slices. Two dimensional apparent diffusion coefficient (ADC) maps are prepared from DW images with b-values 0 and 81 s/mm2 respectively. We estimate porosity quantitatively from each MR slices at temperature -3, -5, -7 and -12oC by using image analysis technique. Gassmann equation is applied to calculate compressional wave velocity from the porosity data and compared with the measured velocity obtained by waveform analysis technique. The NMR results show the existence of high and low mobility unfrozen brine in the pore space. MR imaging shows the heterogeneously distributed porosity values within a single slice with low porosity and high
PARTIAL REFLECTION AND TRAPPING OF A FAST-MODE WAVE IN SOLAR CORONAL ARCADE LOOPS
Kumar, Pankaj; Innes, D. E.
2015-04-20
We report on the first direct observation of a fast-mode wave propagating along and perpendicular to cool (171 Å) arcade loops observed by the Solar Dynamics Observatory/Atmospheric Imaging Assembly (AIA). The wave was associated with an impulsive/compact flare near the edge of a sunspot. The EUV wavefront expanded radially outward from the flare center and decelerated in the corona from 1060 to 760 km s{sup −1} within ∼3–4 minutes. Part of the EUV wave propagated along a large-scale arcade of cool loops and was partially reflected back to the flare site. The phase speed of the wave was about 1450 km s{sup −1}, which is interpreted as a fast-mode wave. A second overlying loop arcade, orientated perpendicular to the cool arcade, is heated and becomes visible in the AIA hot channels. These hot loops sway in time with the EUV wave, as it propagated to and fro along the lower loop arcade. We suggest that an impulsive energy release at one of the footpoints of the arcade loops causes the onset of an EUV shock wave that propagates along and perpendicular to the magnetic field.
Partial denture metal framework may harbor potentially pathogenic bacteria
Bernardes, Luciano Angelo de Souza; Gomes, Sabrina Carvalho; Silva, Alecsandro Moura
2015-01-01
PURPOSE The aim of this study was to characterize and compare bacterial diversity on the removable partial denture (RPD) framework over time. MATERIALS AND METHODS This descriptive pilot study included five women who were rehabilitated with free-end mandibular RPD. The biofilm on T-bar clasps were collected 1 week (t1) and 4 months (t2) after the RPD was inserted (t0). Bacterial 16S rDNA was extracted and PCR amplified. Amplicons were cloned; clones were submitted to cycle sequencing, and sequences were compared with GenBank (98% similarity). RESULTS A total of 180 sequences with more than 499 bp were obtained. Two phylogenetic trees with 84 (t1) and 96 (t2) clones represented the bacteria biofilm at the RPD. About 93% of the obtained phylotypes fell into 25 known species for t1 and 17 for t2, which were grouped in 5 phyla: Firmicutes (t1=82%; t2=60%), Actinobacteria (t1=5%; t2=10%), Bacteroidetes (t1=2%; t2=6%), Proteobacteria (t1=10%; t2=15%) and Fusobacteria (t1=1%; t2=8%). The libraries also include 3 novel phylotypes for t1 and 11 for t2. Library t2 differs from t1 (P=.004); t1 is a subset of the t2 (P=.052). Periodontal pathogens, such as F. nucleatum, were more prevalent in t2. CONCLUSION The biofilm composition of the RPD metal clasps changed along time after RPD wearing. The RPD framework may act as a reservoir for potentially pathogenic bacteria and the RPD wearers may benefit from regular follow-up visits and strategies on prosthesis-related oral health instructions. PMID:26816577
1987-08-01
solution of the Korteweg-de Vries equation ( KdV ), working our way up to the derivation of the multi-soliton solution of the sine-Gordon equation (sG...SOLITARY WAVE SOLUTIONS OF NONLINEAR PARTIAL DIFFERENTIAL EQUATIONS j DiS~~Uj~l. _’UDistribution/Willy Hereman AvaiiLi -itY Codes Technical Summary Report...Key Words: soliton theory, solitary waves, coupled KdV , evolution equations , direct methods, Harry Dym, sine-Gordon Mathematics Department, University
Raman rogue waves in a partially mode-locked fiber laser.
Runge, Antoine F J; Aguergaray, Claude; Broderick, Neil G R; Erkintalo, Miro
2014-01-15
We report on an experimental study of spectral fluctuations induced by intracavity Raman conversion in a passively partially mode-locked, all-normal dispersion fiber laser. Specifically, we use dispersive Fourier transformation to measure single-shot spectra of Raman-induced noise-like pulses, demonstrating that for low cavity gain values Raman emission is sporadic and follows rogue-wave-like probability distributions, while a saturated regime with Gaussian statistics is obtained for high pump powers. Our experiments further reveal intracavity rogue waves originating from cascaded Raman dynamics.
Mynard, Jonathan P; Smolich, Joseph J
2016-04-15
Wave intensity analysis provides detailed insights into factors influencing hemodynamics. However, wave intensity is not a conserved quantity, so it is sensitive to diameter variations and is not distributed among branches of a junction. Moreover, the fundamental relation between waves and hydraulic power is unclear. We, therefore, propose an alternative to wave intensity called "wave power," calculated via incremental changes in pressure and flow (dPdQ) and a novel time-domain separation of hydraulic pressure power and kinetic power into forward and backward wave-related components (ΠP±and ΠQ±). Wave power has several useful properties:1) it is obtained directly from flow measurements, without requiring further calculation of velocity;2) it is a quasi-conserved quantity that may be used to study the relative distribution of waves at junctions; and3) it has the units of power (Watts). We also uncover a simple relationship between wave power and changes in ΠP±and show that wave reflection reduces transmitted power. Absolute values of ΠP±represent wave potential, a recently introduced concept that unifies steady and pulsatile aspects of hemodynamics. We show that wave potential represents the hydraulic energy potential stored in a compliant pressurized vessel, with spatial gradients producing waves that transfer this energy. These techniques and principles are verified numerically and also experimentally with pressure/flow measurements in all branches of a central bifurcation in sheep, under a wide range of hemodynamic conditions. The proposed "wave power analysis," encompassing wave power, wave potential, and wave separation of hydraulic power provides a potent time-domain approach for analyzing hemodynamics. Copyright © 2016 the American Physiological Society.
Lang, Erhard W; Kasprowicz, Magdalena; Smielewski, Peter; Pickard, John; Czosnyka, Marek
2015-08-01
Plateau waves in intracranial pressure (ICP) are frequently recorded in neuro intensive care and are not yet fully understood. To further investigate this phenomenon, we analyzed partial pressure of cerebral oxygen (pbtO2) and a moving correlation coefficient between ICP and mean arterial blood pressure (ABP), called PRx, along with the cerebral oxygen reactivity index (ORx), which is a moving correlation coefficient between cerebral perfusion pressure (CPP) and pbtO2 in an observational study. We analyzed 55 plateau waves in 20 patients after severe traumatic brain injury. We calculated ABP, ABP pulse amplitude (ampABP), ICP, CPP, pbtO2, heart rate (HR), ICP pulse amplitude (ampICP), PRx, and ORx, before, during, and after each plateau wave. The analysis of variance with Bonferroni post hoc test was used to compare the differences in the variables before, during, and after the plateau wave. We considered all plateau waves, even in the same patient, independent because they are separated by long intervals. We found increases for ICP and ampICP according to our operational definitions for plateau waves. PRx increased significantly (p = 0.00026), CPP (p < 0.00001) and pbtO2 (p = 0.00007) decreased significantly during the plateau waves. ABP, ampABP, and HR remained unchanged. PRx during the plateau was higher than before the onset of wave in 40 cases (73 %) with no differences in baseline parameters for those with negative and positive ΔPRx (difference during and after). ORx showed an increase during and a decrease after the plateau waves, however, not statistically significant. PbtO2 overshoot after the wave occurred in 35 times (64 %), the mean difference was 4.9 ± 4.6 Hg (mean ± SD), and we found no difference in baseline parameters between those who overshoot and those who did not overshoot. Arterial blood pressure remains stable in ICP plateau waves, while cerebral autoregulatory indices show distinct changes, which indicate cerebrovascular
Calculation of the Full Scattering Amplitude without Partial Wave Decomposition II
NASA Technical Reports Server (NTRS)
Shertzer, J.; Temkin, A.
2003-01-01
As is well known, the full scattering amplitude can be expressed as an integral involving the complete scattering wave function. We have shown that the integral can be simplified and used in a practical way. Initial application to electron-hydrogen scattering without exchange was highly successful. The Schrodinger equation (SE) can be reduced to a 2d partial differential equation (pde), and was solved using the finite element method. We have now included exchange by solving the resultant SE, in the static exchange approximation. The resultant equation can be reduced to a pair of coupled pde's, to which the finite element method can still be applied. The resultant scattering amplitudes, both singlet and triplet, as a function of angle can be calculated for various energies. The results are in excellent agreement with converged partial wave results.
NASA Technical Reports Server (NTRS)
Shertzer, Janine; Temkin, A.
2003-01-01
As is well known, the full scattering amplitude can be expressed as an integral involving the complete scattering wave function. We have shown that the integral can be simplified and used in a practical way. Initial application to electron-hydrogen scattering without exchange was highly successful. The Schrodinger equation (SE), which can be reduced to a 2d partial differential equation (pde), was solved using the finite element method. We have now included exchange by solving the resultant SE, in the static exchange approximation, which is reducible to a pair of coupled pde's. The resultant scattering amplitudes, both singlet and triplet, calculated as a function of energy are in excellent agreement with converged partial wave results.
Space-time analogy for partially coherent plane-wave-type pulses.
Lancis, Jesús; Torres-Company, Víctor; Silvestre, Enrique; Andrés, Pedro
2005-11-15
In this Letter we extend the well-known space-time duality to partially coherent wave fields and, as a limit case, to incoherent sources. We show that there is a general analogy between the paraxial diffraction of quasi-monochromatic beams of limited spatial coherence and the temporal distortion of partially coherent plane-wave pulses in parabolic dispersive media. Next, coherence-dependent effects in the propagation of Gaussian Schell-model pulses are retrieved from that of their spatial counterpart, the Gaussian Schell-model beam. Finally, the last result allows us to present a source linewidth analysis in an optical fiber communication system operating around the 1.55 microm wavelength window.
NASA Technical Reports Server (NTRS)
Shertzer, Janine; Temkin, A.
2003-01-01
As is well known, the full scattering amplitude can be expressed as an integral involving the complete scattering wave function. We have shown that the integral can be simplified and used in a practical way. Initial application to electron-hydrogen scattering without exchange was highly successful. The Schrodinger equation (SE), which can be reduced to a 2d partial differential equation (pde), was solved using the finite element method. We have now included exchange by solving the resultant SE, in the static exchange approximation, which is reducible to a pair of coupled pde's. The resultant scattering amplitudes, both singlet and triplet, calculated as a function of energy are in excellent agreement with converged partial wave results.
Calculation of the Full Scattering Amplitude without Partial Wave Decomposition II
NASA Technical Reports Server (NTRS)
Shertzer, J.; Temkin, A.
2003-01-01
As is well known, the full scattering amplitude can be expressed as an integral involving the complete scattering wave function. We have shown that the integral can be simplified and used in a practical way. Initial application to electron-hydrogen scattering without exchange was highly successful. The Schrodinger equation (SE) can be reduced to a 2d partial differential equation (pde), and was solved using the finite element method. We have now included exchange by solving the resultant SE, in the static exchange approximation. The resultant equation can be reduced to a pair of coupled pde's, to which the finite element method can still be applied. The resultant scattering amplitudes, both singlet and triplet, as a function of angle can be calculated for various energies. The results are in excellent agreement with converged partial wave results.
NASA Technical Reports Server (NTRS)
Hayes, E. F.; Kouri, D. J.
1971-01-01
Coupled integral equations are derived for the full scattering amplitudes for both reactive and nonreactive channels. The equations do not involve any partial wave expansion and are obtained using channel operators for reactive and nonreactive collisions. These coupled integral equations are similar in nature to equations derived for purely nonreactive collisions of structureless particles. Using numerical quadrature techniques, these equations may be reduced to simultaneous algebraic equations which may then be solved.
A Rosetta Stone Relating Conventions In Photo-Meson Partial Wave Analyses
A.M. Sandorfi, B. Dey, A. Sarantsev, L. Tiator, R. Workman
2012-04-01
A new generation of complete experiments in pseudoscalar meson photo-production is being pursued at several laboratories. While new data are emerging, there is some confusion regarding definitions of asymmetries and the conventions used in partial wave analyses (PWA). We present expressions for constructing asymmetries as coordinate-system independent ratios of cross sections, along with the names used for these ratios by different PWA groups.
NASA Technical Reports Server (NTRS)
Hayes, E. F.; Kouri, D. J.
1971-01-01
Coupled integral equations are derived for the full scattering amplitudes for both reactive and nonreactive channels. The equations do not involve any partial wave expansion and are obtained using channel operators for reactive and nonreactive collisions. These coupled integral equations are similar in nature to equations derived for purely nonreactive collisions of structureless particles. Using numerical quadrature techniques, these equations may be reduced to simultaneous algebraic equations which may then be solved.
A Rosetta Stone relating conventions in photo-meson partial wave analyses
NASA Astrophysics Data System (ADS)
Sandorfi, A. M.; Dey, B.; Sarantsev, A.; Tiator, L.; Workman, R.
2012-04-01
A new generation of complete experiments in pseudoscalar meson photo-production is being pursued at several laboratories. While new data are emerging, there is some confusion regarding definitions of asymmetries and the conventions used in partial wave analyses (PWA). We present expressions for constructing asymmetries as coordinate-system independent ratios of cross sections, along with the names used for these ratios by different PWA groups.
Plateau Waves of Intracranial Pressure and Partial Pressure of Cerebral Oxygen.
Lang, Erhard W; Kasprowicz, Magdalena; Smielewski, Peter; Pickard, John; Czosnyka, Marek
2016-01-01
This study investigates 55 intracranial pressure (ICP) plateau waves recorded in 20 patients after severe traumatic brain injury (TBI) with a focus on a moving correlation coefficient between mean arterial pressure (ABP) and ICP, called PRx, which serves as a marker of cerebrovascular reactivity, and a moving correlation coefficient between ABP and cerebral partial pressure of oxygen (pbtO2), called ORx, which serves as a marker for cerebral oxygen reactivity. ICP and ICPamplitude increased significantly during the plateau waves, whereas CPP and pbtO2 decreased significantly. ABP, ABP amplitude, and heart rate remained unchanged. In 73 % of plateau waves PRx increased during the wave. ORx showed an increase during and a decrease after the plateau waves, which was not statistically significant. Our data show profound cerebral vasoparalysis on top of the wave and, to a lesser extent, impairment of cerebral oxygen reactivity. The different behavior of the indices may be due to the different latencies of the cerebral blood flow and oxygen level control mechanisms. While cerebrovascular reactivity is a rapidly reacting mechanism, cerebral oxygen reactivity is slower.
NASA Astrophysics Data System (ADS)
Gabovich, Alexander M.; Li, Mai Suan; Szymczak, Henryk; Voitenko, Alexander I.
2015-08-01
Quasiparticle tunnel current either between identical d -wave superconductors partially gapped by charge density waves (SCDWs) or between an SCDW and a normal metal was calculated. The cases of unidirectional and checkerboard CDWs were considered. The tunnel conductance was found in both cases to possess a number of peculiarities, which cannot be described by introducing a single combined gap. The results are in qualitative agreement with experimental data obtained for a number of cuprates by the scanning tunnel spectroscopy, intrinsic-tunneling, and break-junction measurements. The difference between the experiment and the theory seems to stem from the spread of gap values occurring due to the intrinsic spatial inhomogeneity of nonstoichiometric oxides and reflected in the cuprate tunnel spectra.
The Potential for Ambient Plasma Wave Propulsion
NASA Technical Reports Server (NTRS)
Gilland, James H.; Williams, George J.
2016-01-01
A truly robust space exploration program will need to make use of in-situ resources as much as possible to make the endeavor affordable. Most space propulsion concepts are saddled with one fundamental burden; the propellant needed to produce momentum. The most advanced propulsion systems currently in use utilize electric and/or magnetic fields to accelerate ionized propellant. However, significant planetary exploration missions in the coming decades, such as the now canceled Jupiter Icy Moons Orbiter, are restricted by propellant mass and propulsion system lifetimes, using even the most optimistic projections of performance. These electric propulsion vehicles are inherently limited in flexibility at their final destination, due to propulsion system wear, propellant requirements, and the relatively low acceleration of the vehicle. A few concepts are able to utilize the environment around them to produce thrust: Solar or magnetic sails and, with certain restrictions, electrodynamic tethers. These concepts focus primarily on using the solar wind or ambient magnetic fields to generate thrust. Technically immature, quasi-propellantless alternatives lack either the sensitivity or the power to provide significant maneuvering. An additional resource to be considered is the ambient plasma and magnetic fields in solar and planetary magnetospheres. These environments, such as those around the Sun or Jupiter, have been shown to host a variety of plasma waves. Plasma wave propulsion takes advantage of an observed astrophysical and terrestrial phenomenon: Alfven waves. These are waves that propagate in the plasma and magnetic fields around and between planets and stars. The generation of Alfven waves in ambient magnetic and plasma fields to generate thrust is proposed as a truly propellantless propulsion system which may enable an entirely new matrix of exploration missions. Alfven waves are well known, transverse electromagnetic waves that propagate in magnetized plasmas at
NASA Astrophysics Data System (ADS)
Marston, Philip L.; Zhang, Likun
2016-11-01
When evaluating radiation forces on spheres in soundfields (with or without orbital-angular momentum) the interpretation of analytical results is greatly simplified by retaining the use of s-function notation for partial-wave coefficients imported into acoustics from quantum scattering theory in the 1970s. This facilitates easy interpretation of various efficiency factors. For situations in which dissipation is negligible, each partial-wave s-function becomes characterized by a single parameter: a phase shift allowing for all possible situations. These phase shifts are associated with scattering by plane traveling waves and the incident wavefield of interest is separately parameterized. (When considering outcomes, the method of fabricating symmetric objects having a desirable set of phase shifts becomes a separate issue.) The existence of negative radiation force "islands" for beams reported in 2006 by Marston is manifested. This approach and consideration of conservation theorems illustrate the unphysical nature of various claims made by other researchers. This approach is also directly relevant to objects in standing waves. Supported by ONR.
HEATING OF THE PARTIALLY IONIZED SOLAR CHROMOSPHERE BY WAVES IN MAGNETIC STRUCTURES
Shelyag, S.; Przybylski, D.; Khomenko, E.; Vicente, A. de
2016-03-01
In this paper, we show a “proof of concept” of the heating mechanism of the solar chromosphere due to wave dissipation caused by the effects of partial ionization. Numerical modeling of non-linear wave propagation in a magnetic flux tube, embedded in the solar atmosphere, is performed by solving a system of single-fluid quasi-MHD equations, which take into account the ambipolar term from the generalized Ohm’s law. It is shown that perturbations caused by magnetic waves can be effectively dissipated due to ambipolar diffusion. The energy input by this mechanism is continuous and shown to be more efficient than dissipation of static currents, ultimately leading to chromospheric temperature increase in magnetic structures.
Heating of the Partially Ionized Solar Chromosphere by Waves in Magnetic Structures
NASA Astrophysics Data System (ADS)
Shelyag, S.; Khomenko, E.; de Vicente, A.; Przybylski, D.
2016-03-01
In this paper, we show a “proof of concept” of the heating mechanism of the solar chromosphere due to wave dissipation caused by the effects of partial ionization. Numerical modeling of non-linear wave propagation in a magnetic flux tube, embedded in the solar atmosphere, is performed by solving a system of single-fluid quasi-MHD equations, which take into account the ambipolar term from the generalized Ohm’s law. It is shown that perturbations caused by magnetic waves can be effectively dissipated due to ambipolar diffusion. The energy input by this mechanism is continuous and shown to be more efficient than dissipation of static currents, ultimately leading to chromospheric temperature increase in magnetic structures.
Study of the potential of wave energy in Malaysia
NASA Astrophysics Data System (ADS)
Tan, Wan Ching; Chan, Keng Wai; Ooi, Heivin
2017-07-01
Renewable energy is generally defined as energy harnessed from resources which are naturally replenished. It is an alternative to the current conventional energy sources such as natural gas, oil and coal, which are nonrenewable. Besides being nonrenewable, the harnessing of these resources generally produce by-products which could be potentially harmful to the environment. On the contrary, the generation from renewable energy does not pose environmental degradation. Some examples of renewable energy sources are sunlight, wind, tides, waves and geothermal heat. Wave energy is considered as one of the most promising marine renewable resources and is becoming commercially viable quicker than other renewable technologies at an astonishing growth rate. This paper illustrates the working principle of wave energy converter (WEC) and the availability of wave energy in Malaysia oceans. A good understanding of the behaviour of ocean waves is important for designing an efficient WEC as the characteristics of the waves in shallow and deep water are different. Consequently, wave energy converters are categorized into three categories on shore, near shore and offshore. Therefore, the objectives of this study is ought to be carried out by focusing on the formation of waves and wave characteristics in shallow as well as in deep water. The potential sites for implementation of wave energy harvesting technology in Malaysia and the wave energy available in the respective area were analysed. The potential of wave energy in Malaysia were tabulated and presented with theoretical data. The interaction between motion of waves and heave buoys for optimum phase condition by using the mass and diameter as the variables were investigated.
NASA Astrophysics Data System (ADS)
Oh, Ju-Won; Alkhalifah, Tariq
2016-09-01
Multiparameter full waveform inversion (FWI) applied to an elastic orthorhombic model description of the subsurface requires in theory a nine-parameter representation of each pixel of the model. Even with optimal acquisition on the Earth surface that includes large offsets, full azimuth, and multicomponent sensors, the potential for trade-off between the elastic orthorhombic parameters are large. The first step to understanding such trade-off is analysing the scattering potential of each parameter, and specifically, its scattering radiation patterns. We investigate such radiation patterns for diffraction and for scattering from a horizontal reflector considering a background isotropic model. The radiation patterns show considerable potential for trade-off between the parameters and the potentially limited resolution in their recovery. The radiation patterns of C11, C22, and C33 are well separated so that we expect to recover these parameters with limited trade-offs. However, the resolution of their recovery represented by recovered range of model wavenumbers varies between these parameters. We can only invert for the short wavelength components (reflection) of C33 while we can mainly invert for the long wavelength components (transmission) of the elastic coefficients C11 and C22 if we have large enough offsets. The elastic coefficients C13, C23, and C12 suffer from strong trade-offs with C55, C44, and C66, respectively. The trade-offs between C13 and C55, as well as C23 and C44, can be partially mitigated if we acquire P-SV and SV-SV waves. However, to reduce the trade-offs between C12 and C66, we require credible SH-SH waves. The analytical radiation patterns of the elastic constants are supported by numerical gradients of these parameters.
Almassalha, Luay M.; Bauer, Greta M.; Chandler, John E.; Gladstein, Scott; Cherkezyan, Lusik; Stypula-Cyrus, Yolanda; Weinberg, Samuel; Zhang, Di; Thusgaard Ruhoff, Peder; Roy, Hemant K.; Subramanian, Hariharan; Chandel, Navdeep S.; Szleifer, Igal; Backman, Vadim
2016-01-01
The organization of chromatin is a regulator of molecular processes including transcription, replication, and DNA repair. The structures within chromatin that regulate these processes span from the nucleosomal (10-nm) to the chromosomal (>200-nm) levels, with little known about the dynamics of chromatin structure between these scales due to a lack of quantitative imaging technique in live cells. Previous work using partial-wave spectroscopic (PWS) microscopy, a quantitative imaging technique with sensitivity to macromolecular organization between 20 and 200 nm, has shown that transformation of chromatin at these length scales is a fundamental event during carcinogenesis. As the dynamics of chromatin likely play a critical regulatory role in cellular function, it is critical to develop live-cell imaging techniques that can probe the real-time temporal behavior of the chromatin nanoarchitecture. Therefore, we developed a live-cell PWS technique that allows high-throughput, label-free study of the causal relationship between nanoscale organization and molecular function in real time. In this work, we use live-cell PWS to study the change in chromatin structure due to DNA damage and expand on the link between metabolic function and the structure of higher-order chromatin. In particular, we studied the temporal changes to chromatin during UV light exposure, show that live-cell DNA-binding dyes induce damage to chromatin within seconds, and demonstrate a direct link between higher-order chromatin structure and mitochondrial membrane potential. Because biological function is tightly paired with structure, live-cell PWS is a powerful tool to study the nanoscale structure–function relationship in live cells. PMID:27702891
Almassalha, Luay M; Bauer, Greta M; Chandler, John E; Gladstein, Scott; Cherkezyan, Lusik; Stypula-Cyrus, Yolanda; Weinberg, Samuel; Zhang, Di; Thusgaard Ruhoff, Peder; Roy, Hemant K; Subramanian, Hariharan; Chandel, Navdeep S; Szleifer, Igal; Backman, Vadim
2016-10-18
The organization of chromatin is a regulator of molecular processes including transcription, replication, and DNA repair. The structures within chromatin that regulate these processes span from the nucleosomal (10-nm) to the chromosomal (>200-nm) levels, with little known about the dynamics of chromatin structure between these scales due to a lack of quantitative imaging technique in live cells. Previous work using partial-wave spectroscopic (PWS) microscopy, a quantitative imaging technique with sensitivity to macromolecular organization between 20 and 200 nm, has shown that transformation of chromatin at these length scales is a fundamental event during carcinogenesis. As the dynamics of chromatin likely play a critical regulatory role in cellular function, it is critical to develop live-cell imaging techniques that can probe the real-time temporal behavior of the chromatin nanoarchitecture. Therefore, we developed a live-cell PWS technique that allows high-throughput, label-free study of the causal relationship between nanoscale organization and molecular function in real time. In this work, we use live-cell PWS to study the change in chromatin structure due to DNA damage and expand on the link between metabolic function and the structure of higher-order chromatin. In particular, we studied the temporal changes to chromatin during UV light exposure, show that live-cell DNA-binding dyes induce damage to chromatin within seconds, and demonstrate a direct link between higher-order chromatin structure and mitochondrial membrane potential. Because biological function is tightly paired with structure, live-cell PWS is a powerful tool to study the nanoscale structure-function relationship in live cells.
On the turbulence generated by the potential surface waves
NASA Astrophysics Data System (ADS)
Benilov, A. Y.
2012-11-01
The turbulence (the random vortex motions) of the upper ocean is nourished by the energy and momentum of the surface waves (the potential motion). The statistical characteristics of the turbulence (turbulent kinetic energy, dissipation rate, and Reynolds stresses) depend on the state of the ocean surface waves. This paper discusses the possibilities of generating this turbulence using the vortex instability of the potential surface waves. The vortex component of fluctuations of velocity field and possibly the interaction between both the vortex and potential motions cause the vertical transport of the momentum. The Reynolds tensor is a linear function of the correlation tensor of vortex field. The initial small vortex perturbations always exist in the upper ocean because of the molecular viscosity influences, especially near the free surface, and the fluctuations of the seawater density. The horizontal inhomogeneities of the seawater density produce the vortex field even if the initial vorticity was zero and the initial flow was the potential flow. The evolution of the small initial vortex disturbances in the velocity field of potential linear surface waves is reduced to a coupled set of linear ordinary differential equations of the first order with periodic coefficients. The solution of this problem shows that the small initial vortex perturbations of potential linear surface waves always grow. The initial small vortex perturbations interacting with the potential surface wave produce the small-scale turbulence (Novikov's turbulence) that finally causes the viscous dissipation of the potential surface wave. The wave-induced turbulence can be considered as developed turbulence with a well distinguishable range of the turbulent wave numberskwhere turbulence obeys the Kolmogorov's self-similarity law.
Wave packet motion in harmonic potential and computer visualization
NASA Technical Reports Server (NTRS)
Tsuru, Hideo; Kobayashi, Takeshi
1993-01-01
Wave packet motions of a single electron in harmonic potentials or a magnetic field are obtained analytically. The phase of the wave function which depends on both time and space is also presented explicitly. The probability density of the electron changes its width and central position periodically. These results are visualized using computer animation techniques.
Surface-wave potential for triggering tectonic (nonvolcanic) tremor
Hill, D.P.
2010-01-01
Source processes commonly posed to explain instances of remote dynamic triggering of tectonic (nonvolcanic) tremor by surface waves include frictional failure and various modes of fluid activation. The relative potential for Love- and Rayleigh-wave dynamic stresses to trigger tectonic tremor through failure on critically stressed thrust and vertical strike-slip faults under the Coulomb-Griffith failure criteria as a function of incidence angle is anticorrelated over the 15- to 30-km-depth range that hosts tectonic tremor. Love-wave potential is high for strike-parallel incidence on low-angle reverse faults and null for strike-normal incidence; the opposite holds for Rayleigh waves. Love-wave potential is high for both strike-parallel and strike-normal incidence on vertical, strike-slip faults and minimal for ~45?? incidence angles. The opposite holds for Rayleigh waves. This pattern is consistent with documented instances of tremor triggered by Love waves incident on the Cascadia mega-thrust and the San Andreas fault (SAF) in central California resulting from shear failure on weak faults (apparent friction, ????? 0.2). However, documented instances of tremor triggered by surface waves with strike-parallel incidence along the Nankai megathrust beneath Shikoku, Japan, is associated primarily with Rayleigh waves. This is consistent with the tremor bursts resulting from mixed-mode failure (crack opening and shear failure) facilitated by near-lithostatic ambient pore pressure, low differential stress, with a moderate friction coefficient (?? ~ 0.6) on the Nankai subduction interface. Rayleigh-wave dilatational stress is relatively weak at tectonic tremor source depths and seems unlikely to contribute significantly to the triggering process, except perhaps for an indirect role on the SAF in sustaining tremor into the Rayleigh-wave coda that was initially triggered by Love waves.
RESONANTLY DAMPED KINK MAGNETOHYDRODYNAMIC WAVES IN A PARTIALLY IONIZED FILAMENT THREAD
Soler, R.; Oliver, R.; Ballester, J. L. E-mail: ramon.oliver@uib.e
2009-12-10
Transverse oscillations of solar filament and prominence threads have been frequently reported. These oscillations have the common features of being of short period (2-10 minutes) and being damped after a few periods. The observations are interpreted as kink magnetohydrodynamic (MHD) wave modes, whereas resonant absorption in the Alfven continuum and ion-neutral collisions are candidates to be the damping mechanisms. Here, we study both analytically and numerically the time damping of kink MHD waves in a cylindrical, partially ionized filament thread embedded in a coronal environment. The thread model is composed of a straight and thin, homogeneous filament plasma, with a transverse inhomogeneous transitional layer where the plasma physical properties vary continuously from filament to coronal conditions. The magnetic field is homogeneous and parallel to the thread axis. We find that the kink mode is efficiently damped by resonant absorption for typical wavelengths of filament oscillations, the damping times being compatible with the observations. Partial ionization does not affect the process of resonant absorption, and the filament plasma ionization degree is only important for the damping for wavelengths much shorter than those observed. To our knowledge, this is the first time that the phenomenon of resonant absorption is studied in a partially ionized plasma.
Investigation of guided wave propagation in pipes fully and partially embedded in concrete.
Leinov, Eli; Lowe, Michael J S; Cawley, Peter
2016-12-01
The application of long-range guided-wave testing to pipes embedded in concrete results in unpredictable test-ranges. The influence of the circumferential extent of the embedding-concrete around a steel pipe on the guided wave propagation is investigated. An analytical model is used to study the axisymmetric fully embedded pipe case, while explicit finite-element and semi-analytical finite-element simulations are utilised to investigate a partially embedded pipe. Model predictions and simulations are compared with full-scale guided-wave tests. The transmission-loss of the T(0,1)-mode in an 8 in. steel pipe fully embedded over an axial length of 0.4 m is found to be in the range of 32-36 dB while it reduces by a factor of 5 when only 50% of the circumference is embedded. The transmission-loss in a fully embedded pipe is mainly due to attenuation in the embedded section while in a partially embedded pipe it depend strongly on the extent of mode-conversion at entry to the embedded-section; low loss modes with energy concentrated in the region of the circumference not-covered with concrete have been identified. The results show that in a fully embedded pipe, inspection beyond a short distance will not be possible, whereas when the concrete is debonded over a fraction of the pipe circumference, inspection of substantially longer lengths may be possible.
Plante, David T.; Goldstein, Michael R.; Cook, Jesse D.; Smith, Richard; Riedner, Brady A.; Rumble, Meredith E.; Jelenchick, Lauren; Roth, Andrea; Tononi, Giulio; Benca, Ruth M.; Peterson, Michael J.
2015-01-01
Objective Changes in slow waves during non-rapid eye movement (NREM) sleep in response to acute total sleep deprivation are well-established measures of sleep homeostasis. This investigation utilized high-density electroencephalography (hdEEG) to examine topographic changes in slow waves during repeated partial sleep deprivation. Methods Twenty-four participants underwent a 6-day sleep restriction protocol. Spectral and period-amplitude analyses of sleep hdEEG data were used to examine changes in slow wave energy, count, amplitude, and slope relative to baseline. Results Changes in slow wave energy were dependent on the quantity of NREM sleep utilized for analysis, with widespread increases during sleep restriction and recovery when comparing data from the first portion of the sleep period, but restricted to recovery sleep if the entire sleep episode was considered. Period-amplitude analysis was less dependent on the quantity of NREM sleep utilized, and demonstrated topographic changes in the count, amplitude, and distribution of slow waves, with frontal increases in slow wave amplitude, numbers of high-amplitude waves, and amplitude/slopes of low amplitude waves resulting from partial sleep deprivation. Conclusions Topographic changes in slow waves occur across the course of partial sleep restriction and recovery. Significance These results demonstrate a homeostatic response to partial sleep loss in humans. PMID:26596212
Plante, David T; Goldstein, Michael R; Cook, Jesse D; Smith, Richard; Riedner, Brady A; Rumble, Meredith E; Jelenchick, Lauren; Roth, Andrea; Tononi, Giulio; Benca, Ruth M; Peterson, Michael J
2016-02-01
Changes in slow waves during non-rapid eye movement (NREM) sleep in response to acute total sleep deprivation are well-established measures of sleep homeostasis. This investigation utilized high-density electroencephalography (hdEEG) to examine topographic changes in slow waves during repeated partial sleep deprivation. Twenty-four participants underwent a 6-day sleep restriction protocol. Spectral and period-amplitude analyses of sleep hdEEG data were used to examine changes in slow wave energy, count, amplitude, and slope relative to baseline. Changes in slow wave energy were dependent on the quantity of NREM sleep utilized for analysis, with widespread increases during sleep restriction and recovery when comparing data from the first portion of the sleep period, but restricted to recovery sleep if the entire sleep episode was considered. Period-amplitude analysis was less dependent on the quantity of NREM sleep utilized, and demonstrated topographic changes in the count, amplitude, and distribution of slow waves, with frontal increases in slow wave amplitude, numbers of high-amplitude waves, and amplitude/slopes of low amplitude waves resulting from partial sleep deprivation. Topographic changes in slow waves occur across the course of partial sleep restriction and recovery. These results demonstrate a homeostatic response to partial sleep loss in humans. Copyright © 2015 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.
Ionizing potential waves and high-voltage breakdown streamers.
NASA Technical Reports Server (NTRS)
Albright, N. W.; Tidman, D. A.
1972-01-01
The structure of ionizing potential waves driven by a strong electric field in a dense gas is discussed. Negative breakdown waves are found to propagate with a velocity proportional to the electric field normal to the wavefront. This causes a curved ionizing potential wavefront to focus down into a filamentary structure, and may provide the reason why breakdown in dense gases propagates in the form of a narrow leader streamer instead of a broad wavefront.
Compact representations of partially coherent undulator radiation suitable for wave propagation
Lindberg, Ryan R.; Kim, Kwang -Je
2015-09-28
Undulator radiation is partially coherent in the transverse plane, with the degree of coherence depending on the ratio of the electron beam phase space area (emittance) to the characteristic radiation wavelength λ. Numerical codes used to predict x-ray beam line performance can typically only propagate coherent fields from the source to the image plane. We investigate methods for representing partially coherent undulator radiation using a suitably chosen set of coherent fields that can be used in standard wave propagation codes, and discuss such “coherent mode expansions” for arbitrary degrees of coherence. In the limit when the electron beam emittance alongmore » at least one direction is much larger than λ the coherent modes are orthogonal and therefore compact; when the emittance approaches λ in both planes we discuss an economical method of defining the relevant coherent fields that samples the electron beam phase space using low-discrepancy sequences.« less
Partial wave analysis of 3 π with pion and photon beams
NASA Astrophysics Data System (ADS)
Jackura, Andrew; Mikhasenko, Mikhail; Szczepaniak, Adam; Ketzer, Bernhard; Joint Physics Analysis Center Collaboration
2016-09-01
We present some results on the analysis of 3 π resonances from peripheral scattering of pions off of nuclear targets. The analysis is motivated by the recent release of the largest data set on diffractively produced three pions by the COMPASS collaboration. The model emphasizes the 3 π production process and their final state interactions which satisfy S-matrix principles. We apply our model to fit partial wave intensities and relative phases from COMPASS in the JPC =2-+ sector and search for resonances. We then discuss the extension of our formalism to photon beams to be used in the GlueX experiment.
Nucleon-nucleon scattering in the 1S0 partial wave in the modified Weinberg approach
NASA Astrophysics Data System (ADS)
Gasparyan, A. M.; Epelbaum, E.; Gegelia, J.; Krebs, H.
2016-03-01
Nucleon-nucleon scattering in the 1S0 partial wave is considered in chiral effective field theory within the recently suggested renormalizable formulation based on the Kadyshevsky equation. Contact interactions are taken into account beyond the leading-order approximation. The subleading contact terms are included non-perturbatively by means of subtractive renormalization. The dependence of the phase shifts on the choice of the renormalization condition is discussed. Perturbative inclusion of the subleading contact interaction is found to be justified only very close to threshold. The low-energy theorems are reproduced significantly better compared with the leading order results.
Highly directive Fabry-Perot leaky-wave nanoantennas based on optical partially reflective surfaces
Lorente-Crespo, M.; Mateo-Segura, C.
2015-05-04
Nanoantennas enhance the conversion between highly localized electromagnetic fields and far-field radiation. Here, we investigate the response of a nano-patch partially reflective surface backed with a silver mirror to an optical source embedded at the centre of the structure. Using full wave simulations, we demonstrate a two orders of magnitude increased directivity compared to the isotropic radiator, 50% power confinement to a 13.8° width beam and a ±16 nm bandwidth. Our antenna does not rely on plasmonic phenomena thus reducing non-radiative losses and conserving source coherence.
Evaporative cooling of metastable helium in the multi-partial-wave regime
Nguyen, Scott V.; Doret, S. Charles; Connolly, Colin B.; Michniak, Robert A.; Doyle, John M.; Ketterle, Wolfgang
2005-12-15
Metastable helium is buffer gas cooled, magnetically trapped, and evaporatively cooled in large numbers. 10{sup 11} {sup 4}He{sup *} atoms are trapped at an initial temperature of 400 mK and evaporatively cooled into the ultracold regime, resulting in a cloud of 2{+-}0.5x10{sup 9} atoms at 1.4{+-}0.2 mK. Efficient evaporation indicates low collisional loss for {sup 4}He{sup *} in both the ultracold and multi-partial-wave regime, in agreement with theory.
The N/D method with non-perturbative left-hand-cut discontinuity and the S10NN partial wave
NASA Astrophysics Data System (ADS)
Entem, D. R.; Oller, J. A.
2017-10-01
In this letter we introduce an integral equation that allows to calculate the exact left-hand-cut discontinuity for an uncoupled S-wave partial-wave amplitude in potential scattering for a given finite-range potential. In particular this is applied here to the S10 nucleon-nucleon (NN) partial wave. The calculation of Δ (A) is completely fixed by the potential because short-range physics (corresponding to integrated out degrees of freedom within the low-energy Effective Field Theory) does not contribute to Δ (A). The results obtained from the N / D method for a partial-wave amplitude are rigorous, since now the discontinuities along the left-hand cut and right-hand cut are exactly known. This solves in this case the open question with respect to the N / D method and the effect on the final result of the non-perturbative iterative diagrams in the evaluation of Δ (A). The solution of this problem also implies the equivalence of the N / D method and the Lippmann-Schwinger (LS) equation for the nonsingular one-pion exchange S10NN potential (Yukawa potential). The equivalence between the N / D method with one extra subtraction and the LS equation renormalized with one counterterm or with subtractive renormalization also holds for the singular attractive S10NN potentials calculated by including higher orders in Chiral Perturbation Theory (ChPT). However, the N / D method is more flexible and, rather straightforwardly, it allows to evaluate partial-wave amplitudes with a higher number of extra subtractions, that we fix in terms of shape parameters within the effective range expansion. We give results up to three extra subtractions in the N / D method, which provide a rather accurate reproduction of the S10NN phase shifts when the NNLO ChPT potential is employed. Our new method then provides a general theory to renormalize non-perturbatively singular and regular potentials in scattering that can be extended to higher partial waves as well as to coupled channel scattering.
NASA Astrophysics Data System (ADS)
Xiao, Xifeng
One of the main drawbacks that prevent the extensive application of free space laser communications is the atmospheric turbulence through which the beam must propagate. For the past four decades, much attention has been devoted to finding different methods to overcome this difficulty. A partially coherent beam (PCB) has been recognized as an effective approach to improve the performance of an atmospheric link. It has been examined carefully with most analyses considering the Gaussian Schell-model (GSM) beam. However, practical PCBs may not follow GSM theory and are better examined through some numerical simulation approach such as a wave optics simulation. Consequently, an approach for modeling the spatially PCB in wave optics simulation is presented here. The approach involves the application of a sequence of random phase screens to an initial beam field and the summation of the intensity results after propagation. The relationship between the screen parameters and the spatial coherence function for the beam is developed and the approach is verified by comparing results with analytic formulations for a Gaussian Schell-model (GSM) beam. A variety of simulation studies were performed for this dissertation. The propagation through turbulence of a coherent beam and a particular version of a PCB, a pseudo-partially coherent beam (PPCB), is analyzed. The beam is created with a sequence of several Gaussian random phase screens for each atmospheric realization. The average intensity profiles, the scintillation index and aperture averaging factor for a horizontal propagation scenario are examined. Comparisons between these results and their corresponding analytic results for the well-known GSM beam are also made. Cumulative probability density functions for the received irradiance are initially investigated. Following the general simulation investigations, a performance metric is proposed as a general measure for optimizing the transverse coherence length of a partial
Two-nucleon higher partial-wave scattering from lattice QCD
NASA Astrophysics Data System (ADS)
Berkowitz, Evan; Kurth, Thorsten; Nicholson, Amy; Joó, Bálint; Rinaldi, Enrico; Strother, Mark; Vranas, Pavlos M.; Walker-Loud, André
2017-02-01
We present a determination of nucleon-nucleon scattering phase shifts for ℓ ≥ 0. The S, P, D and F phase shifts for both the spin-triplet and spin-singlet channels are computed with lattice Quantum ChromoDynamics. For ℓ > 0, this is the first lattice QCD calculation using the Lüscher finite-volume formalism. This required the design and implementation of novel lattice methods involving displaced sources and momentum-space cubic sinks. To demonstrate the utility of our approach, the calculations were performed in the SU (3)-flavor limit where the light quark masses have been tuned to the physical strange quark mass, corresponding to mπ =mK ≈ 800 MeV. In this work, we have assumed that only the lowest partial waves contribute to each channel, ignoring the unphysical partial wave mixing that arises within the finite-volume formalism. This assumption is only valid for sufficiently low energies; we present evidence that it holds for our study using two different channels. Two spatial volumes of V ≈(3.5 fm) 3 and V ≈(4.6 fm) 3 were used. The finite-volume spectrum is extracted from the exponential falloff of the correlation functions. Said spectrum is mapped onto the infinite volume phase shifts using the generalization of the Lüscher formalism for two-nucleon systems.
Two-fluid modeling of magnetosonic wave propagation in the partially ionized solar chromosphere
NASA Astrophysics Data System (ADS)
Maneva, Yana; Alvarez Laguna, Alejandro; Lani, Andrea; Poedts, Stefaan
2016-04-01
We perform 2D two-fluid simulations to study the effects of ion-neutral interactions on the propagation of magnetosonic waves in the partially ionized solar chromosphere, where the number density of neutrals significantly exceeds the number density of protons at low heights. Thus modeling the neutral-ion interactions and studying the effect of neutrals on the ambient plasma properties becomes important for better understanding the observed emission lines and the propagation of disturbances from the photosphere to the transition region and the corona. The role of charged particles (electrons and ions) is combined within resistive MHD approach with Coulomb collisions and anisotropic heat flux determined by Braginskii's transport coefficients. The electromagnetic fields are evolved according to the full Maxwell equations, allowing for propagation of higher frequency waves neglected by the standard MHD approximation. Separate mass, momentum and energy conservation equations are considered for the neutrals and the interaction between the different fluids is determined by the chemical reactions, such as impact ionization, radiative recombination and charge exchange, provided as additional source terms. To initialize the system we consider an ideal gas equation of state with equal initial temperatures for the electrons, ions and the neutrals and different density profiles. The initial temperature and density profiles are height-dependent and follow VAL C atmospheric model for the solar chromosphere. We have searched for a chemical and collisional equilibrium between the ions and the neutrals to minimize any unphysical outflows and artificial heating induced by initial pressure imbalances. Including different magnetic field profiles brings new source of plasma heating through Ohmic dissipation. The excitation and propagation of the magnetosonic waves depends on the type of the external velocity driver. As the waves propagate through the gravitationally stratified media
Wave Modes Trapped in Rotating Nonlinear Potentials
NASA Astrophysics Data System (ADS)
Li, Yongyao; Pang, Wei; Malomed, Boris A.
We study modes trapped in a rotating ring with the local strength of the nonlinearity modulated as \\cos (2θ ) , where θ is the azimuthal angle. This modulation pattern may be of three different types: self-focusing (SF), self-defocusing (SDF), and alternating SF-SDF. The model, based on the nonlinear Schrödinger (NLS) equation with periodic boundary conditions, applies to the light propagation in a twisted pipe waveguide, and to a Bose-Einstein condensate (BEC) loaded into a toroidal trap, under the action of the rotating nonlinear pseudopotential induced by means of the Feshbach resonance in an inhomogeneous external field. This is the difference from the recently considered similar setting with the rotating linear potential. In the SF, SDF, and alternating regimes, four, three, and five different types of stable trapped modes are identified, respectively: even, odd, second-harmonic (2H), symmetry-breaking, and 2H-breaking ones. The shapes and stability of these modes, together with transitions between them, are investigated in the first rotational Brillouin zone. Ground-state modes are identified in each regime. Boundaries between symmetric and asymmetric modes are also found in an analytical form, by means of a two-mode approximation.
Reconstruction of a time-dependent potential from wave measurements
NASA Astrophysics Data System (ADS)
Gerken, Thies; Lechleiter, Armin
2017-09-01
We add a time-dependent potential to the inhomogeneous wave equation and consider the task of reconstructing this potential from measurements of the wave field. This dynamic inverse problem becomes more involved compared to static parameters, as, e.g. the dimensions of the parameter space do considerably increase. We give a specifically tailored existence and uniqueness result for the wave equation and compute the Fréchet derivative of the solution operator, for which also show the tangential cone condition. These results motivate the numerical reconstruction of the potential via successive linearization and regularized Newton-like methods. We present several numerical examples showing feasibility, reconstruction quality, and time efficiency of the resulting algorithm.
Generalized Sagdeev potential theory for shock waves modeling
NASA Astrophysics Data System (ADS)
Akbari-Moghanjoughi, M.
2017-05-01
In this paper, we develop an innovative approach to study the shock wave propagation using the Sagdeev potential method. We also present an analytical solution for Korteweg de Vries Burgers (KdVB) and modified KdVB equation families with a generalized form of the nonlinearity term which agrees well with the numerical one. The novelty of the current approach is that it is based on a simple analogy of the particle in a classical potential with the variable particle energy providing one with a deeper physical insight into the problem and can easily be extended to more complex physical situations. We find that the current method well describes both monotonic and oscillatory natures of the dispersive-diffusive shock structures in different viscous fluid configurations. It is particularly important that all essential parameters of the shock structure can be deduced directly from the Sagdeev potential in small and large potential approximation regimes. Using the new method, we find that supercnoidal waves can decay into either compressive or rarefactive shock waves depending on the initial wave amplitude. Current investigation provides a general platform to study a wide range of phenomena related to nonlinear wave damping and interactions in diverse fluids including plasmas.
Lin, D.-H.
2004-05-01
Partial wave theory of a three dimensional scattering problem for an arbitrary short range potential and a nonlocal Aharonov-Bohm magnetic flux is established. The scattering process of a 'hard sphere'-like potential and the magnetic flux is examined. An anomalous total cross section is revealed at the specific quantized magnetic flux at low energy which helps explain the composite fermion and boson model in the fractional quantum Hall effect. Since the nonlocal quantum interference of magnetic flux on the charged particles is universal, the nonlocal effect is expected to appear in a quite general potential system and will be useful in understanding some other phenomena in mesoscopic physics.
Correlations of $\pi N$ partial waves for multireaction analyses
Doring, M.; Revier, J.; Ronchen, D.; Workman, R. L.
2016-06-15
In the search for missing baryonic resonances, many analyses include data from a variety of pion- and photon-induced reactions. For elastic πN scattering, however, usually the partial waves of the SAID (Scattering Analysis Interactive Database) or other groups are fitted, instead of data. We provide the partial-wave covariance matrices needed to perform correlated χ^{2} fits, in which the obtained χ^{2} equals the actual χ^{2} up to nonlinear and normalization corrections. For any analysis relying on partial waves extracted from elastic pion scattering, this is a prerequisite to assess the significance of resonance signals and to assign any uncertainty on results. Lastly, the influence of systematic errors is also considered.
Correlations of $\pi N$ partial waves for multireaction analyses
Doring, M.; Revier, J.; Ronchen, D.; Workman, R. L.
2016-06-15
In the search for missing baryonic resonances, many analyses include data from a variety of pion- and photon-induced reactions. For elastic πN scattering, however, usually the partial waves of the SAID (Scattering Analysis Interactive Database) or other groups are fitted, instead of data. We provide the partial-wave covariance matrices needed to perform correlated χ^{2} fits, in which the obtained χ^{2} equals the actual χ^{2} up to nonlinear and normalization corrections. For any analysis relying on partial waves extracted from elastic pion scattering, this is a prerequisite to assess the significance of resonance signals and to assign any uncertainty on results. Lastly, the influence of systematic errors is also considered.
Hydrate Formation and Compressional Wave Development in Partially Saturated Ottawa Sand
NASA Astrophysics Data System (ADS)
Waite, W. F.; Winters, W. J.; Mason, D. H.
2003-04-01
Methane gas hydrate was synthesized in three uniform mixtures of Ottawa sand and distilled water using the Gas Hydrate And Sediment Test Laboratory Instrument (GHASTLI) to examine hydrate formation behavior and its effects on compressional wave transmission in partially saturated granular material. The porosities were 38, 39, and 37% with 16, 31, and 58% respectively of the pore space in each specimen filled with water. Each sample was pressurized internally to 12 MPa with methane gas and consolidated to an effective stress of 250 kPa. Sample temperatures were reduced to 279 K, 7 K below the sI gas hydrate stability curve at 12 MPa. A pair of 1 Mhz transducers located in endcaps above and below the cylindrical sample was used to send a compressional wave through the sample's central axis to monitor the acoustic response to hydrate growth. Waveforms were collected in five to fifteen minute intervals for the ~100 to ~900 hours required for the acoustic signal to stabilize, an indication that the final hydrate distribution had been achieved. Here we consider two components of the acoustic waveform: the first arrival, which provides the compressional wave speed (Vp) in samples of known length, and the signal amplitude, which increases with improved signal transmission efficiency. Hydrate forming in granular media can increase both Vp and signal amplitude by binding individual grains, thereby stiffening the sample. Hydrate formation occurs most efficiently at the water/methane interface, and decreasing pore space water content increases that interfacial area. Consistent with increased formation efficiency, the signal amplitude growth rate, the temperature at which hydrate began to form and the magnitude of the temperature rise associated with exothermal hydrate formation were all higher in samples with lower water contents. Decreasing the pore space water content limits the total amount of hydrate that can form however, and despite the improved hydrate formation
Detection and Analysis of Partial Reflections of HF Waves from the Lower Ionosphere
NASA Astrophysics Data System (ADS)
Erdman, A.; Moore, R. C.
2016-12-01
On the afternoon of August 27, 2011, the western half of the High Frequency Active Auroral Research Program's (HAARP's) HF transmitter repeatedly broadcast a low-power (1 kW/Tx), 4.5-MHz, X-mode polarized, 10 microsecond pulse. The HF beam was directed vertically, and the inter-pulse period was 20 milliseconds. HF observations were performed at Oasis (62° 23' 30" N, 145° 9' 03" W) using two crossed 90-foot folded dipoles. Observations clearly indicate the detection of a ground wave and multiple reflections from different sources at F-region altitudes, which is consistent with digisonde measurements at 4.5 MHz. Additional reflections were detected at a virtual altitude of 90-110 km, and we interpret these reflections as partial reflections from the rapid conductivity change at the base of the ionosphere. We compare these observations with the predictions of a new finite-difference time-domain (FDTD) plasma model. The model is a one-dimensional, second-order accurate, cold plasma FDTD model of the ionosphere extending from ground through the lower F-region. The model accounts for a spatially varying plasma frequency, cyclotron frequency, and electron-neutral collision frequency. We discuss the possibility to analyze partial reflections from the base of the ionosphere as a function of frequency to characterize the reflecting plasma.
X-ray standing wave analysis of nanostructures using partially coherent radiation
Tiwari, M. K. Das, Gangadhar; Bedzyk, M. J.
2015-09-07
The effect of longitudinal (or temporal) coherence on total reflection assisted x-ray standing wave (TR-XSW) analysis of nanoscale materials is quantitatively demonstrated by showing how the XSW fringe visibility can be strongly damped by decreasing the spectral resolution of the incident x-ray beam. The correction for nonzero wavelength dispersion (δλ ≠ 0) of the incident x-ray wave field is accounted for in the model computations of TR-XSW assisted angle dependent fluorescence yields of the nanostructure coatings on x-ray mirror surfaces. Given examples include 90 nm diameter Au nanospheres deposited on a Si(100) surface and a 3 nm thick Zn layer trapped on top a 100 nm Langmuir-Blodgett film coating on a Au mirror surface. Present method opens up important applications, such as enabling XSW studies of large dimensioned nanostructures using conventional laboratory based partially coherent x-ray sources.
Fast solution of elliptic partial differential equations using linear combinations of plane waves
NASA Astrophysics Data System (ADS)
Pérez-Jordá, José M.
2016-02-01
Given an arbitrary elliptic partial differential equation (PDE), a procedure for obtaining its solution is proposed based on the method of Ritz: the solution is written as a linear combination of plane waves and the coefficients are obtained by variational minimization. The PDE to be solved is cast as a system of linear equations A x =b , where the matrix A is not sparse, which prevents the straightforward application of standard iterative methods in order to solve it. This sparseness problem can be circumvented by means of a recursive bisection approach based on the fast Fourier transform, which makes it possible to implement fast versions of some stationary iterative methods (such as Gauss-Seidel) consuming O (N logN ) memory and executing an iteration in O (N log2N ) time, N being the number of plane waves used. In a similar way, fast versions of Krylov subspace methods and multigrid methods can also be implemented. These procedures are tested on Poisson's equation expressed in adaptive coordinates. It is found that the best results are obtained with the GMRES method using a multigrid preconditioner with Gauss-Seidel relaxation steps.
Fast solution of elliptic partial differential equations using linear combinations of plane waves.
Pérez-Jordá, José M
2016-02-01
Given an arbitrary elliptic partial differential equation (PDE), a procedure for obtaining its solution is proposed based on the method of Ritz: the solution is written as a linear combination of plane waves and the coefficients are obtained by variational minimization. The PDE to be solved is cast as a system of linear equations Ax=b, where the matrix A is not sparse, which prevents the straightforward application of standard iterative methods in order to solve it. This sparseness problem can be circumvented by means of a recursive bisection approach based on the fast Fourier transform, which makes it possible to implement fast versions of some stationary iterative methods (such as Gauss-Seidel) consuming O(NlogN) memory and executing an iteration in O(Nlog(2)N) time, N being the number of plane waves used. In a similar way, fast versions of Krylov subspace methods and multigrid methods can also be implemented. These procedures are tested on Poisson's equation expressed in adaptive coordinates. It is found that the best results are obtained with the GMRES method using a multigrid preconditioner with Gauss-Seidel relaxation steps.
A Composite Fermion Hofstadter Problem: Partially Polarized Density Wave States in the FQHE
NASA Astrophysics Data System (ADS)
Murthy, Ganpathy
2000-03-01
It is well known that the 2/5 FQH state can have two translationally invariant ground states, one of which is a singlet and the other fully polarized. A quantum phase transition occurs between these two as a function of the Zeeman field. This can be simply explained in terms of the crossing of Composite Fermion Landau levels. However, recently Kukushkin et al (PRL 82, 3665 (99)) have seen plateaus of half the maximal polarization in the 2/5 fraction at intermediate Zeeman fields. Similar plateaus, which are not allowed for translationally invariant CF states, are seen in other fractions as well. I propose a class of novel partially polarized spin/charge density wave states which display the co-existence of density wave and quantum Hall order (the Hall crystal state). The physical properties of the states, including gaps and collective excitations are computed using the formalism for the FQHE developed recently by Shankar and myself (for details see Murthy and Shankar in "Composite Fermions", Olle Heinonen, Editor).
NASA Astrophysics Data System (ADS)
Blankleider, B.; Afnan, I. R.
1985-04-01
The polarization observables of the reactions parrow parrow --> π+d, parrowp --> darrowπ+, and πdarrow --> πdarrow are investigated. Expressions relating these observables directly to (LSJ) partial wave amplitudes are derived and tabulations of the partial wave contributions are given for some of the observables. Examples are given of how such tabulations can be useful for optimizing the connection between theory and experiment and in suggesting possible new experiments. All observables are also calculated numerically using a unitary few-body model of the NN-πNN system to generate the amplitudes. Sensitivity to the choice of P11 interaction is investigated.
The Future Potential of Wave Power in the US
NASA Astrophysics Data System (ADS)
Previsic, M.; Epler, J.; Hand, M.; Heimiller, D.; Short, W.; Eurek, K.
2012-12-01
The theoretical ocean wave energy resource potential exceeds 50% of the annual domestic energy demand of the US, is located in close proximity of coastal population centers, and, although variable in nature, may be more consistent and predictable than some other renewable generation technologies. As renewable electricity generation technologies, ocean wave energy offers a low air pollutant option for diversifying the US electricity generation portfolio. Furthermore, the output characteristics of these technologies may complement other renewable technologies. This study addresses: (1) The energy extraction potential from the US wave energy resource, (2) The present cost of wave technology in /kW, (3) The estimated cost of energy in /kWh, and (4) Cost levels at which the technology should see significant deployment. RE Vision Consulting in collaboration with NREL engaged in various analyses to establish present-day and future cost profiles for MHK technologies, compiled existing resource assessments and wave energy supply curves, and developed cost and deployment scenarios using the ReEDS analysis model to estimate the present-day technology cost reductions necessary to facilitate significant technology deployment in the US.
How close can we get waves to wave functions, including potential?
NASA Astrophysics Data System (ADS)
Faletič, Sergej
2016-05-01
In the following article we show that mechanical waves on a braced string can have the same shapes as important wave functions in introductory quantum mechanics. A braced string is a string with additional transversal springs that serve as external "potential". The aim is not to suggest teaching quantum mechanics with these analogies. Instead, the aim is to provide students with some additional relevant experience in wave mechanics before they are introduced to quantum mechanics. We show how this experience can be used in a constructivist sense as the basis for building quantum concepts. We consider energy transfer along such string and show that penetration of a wave into a region with high "potential" is not unexpected. We also consider energy transfer between two such strings and show that it can appear point-like even though the wave is an extended object. We also suggest that applying quantization of energy transfer to wave phenomena can explain some of the more difficult to accept features of quantum mechanics.
Bouncing plasmonic waves in half-parabolic potentials
Liu Wei; Neshev, Dragomir N.; Miroshnichenko, Andrey E.; Shadrivov, Ilya V.; Kivshar, Yuri S.
2011-12-15
We introduce a plasmonic analog for the dynamics of a quantum particle under a linear restoring force bouncing off an impenetrable barrier (''quantum paddle ball''). Paddle-ball-type plasmonic potentials are constructed in quadratically modulated metal-dielectric-metal structures with transverse metallic reflecting walls. We show, both analytically and numerically, the full-wave nature of the phenomenon, including plasmon bouncing and complete wave revivals after interference at the boundary. We show that the plasmon paddle-ball dynamics is effectively wavelength independent, opening opportunities for subwavelength manipulations of polychromatic and ultrashort-pulse plasmons.
Localization of a matter wave packet in a disordered potential
Piraud, M.; Bouyer, P.; Aspect, A.; Sanchez-Palencia, L.; Lugan, P.
2011-03-15
We theoretically study the Anderson localization of a matter wave packet in a one-dimensional disordered potential. We develop an analytical model which includes the initial phase-space density of the matter wave and the spectral broadening induced by the disorder. Our approach predicts a behavior of the localized density profile significantly more complex than a simple exponential decay. These results are confirmed by large-scale and long-time numerical calculations. They shed new light on recent experiments with ultracold atoms and may impact their analysis.
Wang, Jimin
2017-06-01
Partial charges of atoms in a molecule and electrostatic potential (ESP) density for that molecule are known to bear a strong correlation. In order to generate a set of point-field force field parameters for molecular dynamics, Kollman and coworkers have extracted atomic partial charges for each of all 20 amino acids using restrained partial charge-fitting procedures from theoretical ESP density obtained from condensed-state quantum mechanics. The magnitude of atomic partial charges for neutral peptide backbone they have obtained is similar to that of partial atomic charges for ionized carboxylate side chain atoms. In this study, the effect of these known atomic partial charges on ESP is examined using computer simulations and compared with the experimental ESP density recently obtained for proteins using electron microscopy. It is found that the observed ESP density maps are most consistent with the simulations that include atomic partial charges of protein backbone. Therefore, atomic partial charges are integral part of atomic properties in protein molecules and should be included in model refinement. © 2017 The Protein Society.
NASA Astrophysics Data System (ADS)
Klochko, M. S.
2014-06-01
The surface waves and bulk acoustic bands were studied taking into account the interaction between the nearest and next-nearest neighbors in a cubic crystal. Expressions for the dispersion relations, the frequencies at which the surface waves split off the bulk spectrum, and the parameters of the amplitude attenuation have been obtained for the crystalline systems in which the surface waves are single-component and single-partial. The calculations were conducted taking into account the discrete nature of crystal lattice for arbitrary values of the two-dimensional wave vector. The analysis has demonstrated that the results obtained in the long-wavelength limit are in full agreement with those calculated in the framework of linear nonlocal elasticity theory. The influence of an adsorbed surface monolayer on the characteristics of the surface waves was studied.
Hansson, T; Lisak, M; Anderson, D
2012-02-10
It is shown that the evolution equations describing partially coherent wave propagation in noninstantaneous Kerr media are integrable and have an infinite number of invariants. A recursion relation for generating these invariants is presented, and it is demonstrated how to express them in the coherent density, self-consistent multimode, mutual coherence, and Wigner formalisms.
Assessment of shock wave lithotripters via cavitation potential
NASA Astrophysics Data System (ADS)
Iloreta, Jonathan I.; Zhou, Yufeng; Sankin, Georgy N.; Zhong, Pei; Szeri, Andrew J.
2007-08-01
A method to characterize shock wave lithotripters by examining the potential for cavitation associated with the lithotripter shock wave (LSW) has been developed. The method uses the maximum radius achieved by a bubble subjected to a LSW as a representation of the cavitation potential for that region in the lithotripter. It is found that the maximum radius is determined by the work done on a bubble by the LSW. The method is used to characterize two reflectors: an ellipsoidal reflector and an ellipsoidal reflector with an insert. The results show that the use of an insert reduced the -6dB volume (with respect to peak positive pressure) from 1.6 to 0.4cm3, the -6dB volume (with respect to peak negative pressure) from 14.5 to 8.3cm3, and reduced the volume characterized by high cavitation potential (i.e., regions characterized by bubbles with radii larger than 429μm) from 103 to 26cm3. Thus, the insert is an effective way to localize the potentially damaging effects of shock wave lithotripsy, and suggests an approach to optimize the shape of the reflector.
Assessment of shock wave lithotripters via cavitation potential
Iloreta, Jonathan I.; Zhou, Yufeng; Sankin, Georgy N.; Zhong, Pei; Szeri, Andrew J.
2008-01-01
A method to characterize shock wave lithotripters by examining the potential for cavitation associated with the lithotripter shock wave (LSW) has been developed. The method uses the maximum radius achieved by a bubble subjected to a LSW as a representation of the cavitation potential for that region in the lithotripter. It is found that the maximum radius is determined by the work done on a bubble by the LSW. The method is used to characterize two reflectors: an ellipsoidal reflector and an ellipsoidal reflector with an insert. The results show that the use of an insert reduced the −6 dB volume (with respect to peak positive pressure) from 1.6 to 0.4 cm3, the −6 dB volume (with respect to peak negative pressure) from 14.5 to 8.3 cm3, and reduced the volume characterized by high cavitation potential (i.e., regions characterized by bubbles with radii larger than 429 µm) from 103 to 26 cm3. Thus, the insert is an effective way to localize the potentially damaging effects of shock wave lithotripsy, and suggests an approach to optimize the shape of the reflector. PMID:19865493
NASA Astrophysics Data System (ADS)
Kuruoǧlu, Zeki C.
2016-11-01
Direct numerical solution of the coordinate-space integral-equation version of the two-particle Lippmann-Schwinger (LS) equation is considered without invoking the traditional partial-wave decomposition. The singular kernel of the three-dimensional LS equation in coordinate space is regularized by a subtraction technique. The resulting nonsingular integral equation is then solved via the Nystrom method employing a direct-product quadrature rule for three variables. To reduce the computational burden of discretizing three variables, advantage is taken of the fact that, for central potentials, the azimuthal angle can be integrated out, leaving a two-variable reduced integral equation. A regularization method for the kernel of the two-variable integral equation is derived from the treatment of the singularity in the three-dimensional equation. A quadrature rule constructed as the direct product of single-variable quadrature rules for radial distance and polar angle is used to discretize the two-variable integral equation. These two- and three-variable methods are tested on the Hartree potential. The results show that the Nystrom method for the coordinate-space LS equation compares favorably in terms of its ease of implementation and effectiveness with the Nystrom method for the momentum-space version of the LS equation.
NASA Astrophysics Data System (ADS)
Yenen, Orhan
2003-05-01
Recent trends in AMO physics is to move from being a passive observer to an active controller of the outcome of quantum phenomena. Full controls of quantum processes require complete information about the quantum system; experiments which measure all the information allowed by quantum mechanics are called "Quantum Mechanically Complete Experiments". For example, when an isolated atom is photoionized, conservation laws limit the allowed partial waves of the photoelectron to a maximum of three. A quantum mechanically complete photoionization experiment then will have to determine all three partial wave probabilities and the two independent phases between the partial waves as a function of ionizing photon energy. From these five parameters all the quantities quantum mechanics allows one to measure can be determined for the "Residual Ion + Photoelectron" system. We have developed experimental methods [1, 2] to determine all three partial wave probabilities of photoelectrons when the residual ion is left in an excited state. Experimentally, Ar atoms are photoionized by circularly polarized synchrotron radiation produced by a unique VUV (vacuum ultraviolet) phase retarder we have installed at the Advanced Light Source (ALS) in Berkeley, CA. We measure the linear and circular polarization of the fine-structure-resolved fluorescent photons from the excited residual ions at specific directions. From the measurements one obtains the relativistic partial wave probabilities of the photoelectron. Our measurements highlight the significance of multielectron processes in photoionization dynamics and provide stringent tests of theory. The results indicate significant spin-dependent relativistic interactions during photoionization. [1] O. Yenen et al., Phys. Rev. Lett. 86, 979 (2001). [2] K. W. McLaughlin et al., Phys. Rev. Lett. 88, 123003 (2002).
Calculation of scattering amplitude without partial wave analysis: Inclusion of exchange
NASA Astrophysics Data System (ADS)
Temkin, Aaron; Shertzer, Janine
2002-05-01
In Ref. [1], a method is given for calculating the scattering amplitude f(Ω) directly. The idea is to calculate the complete wave function Ψ_k( r) numerically and use it in an integral expression for f(Ω). The original application was for electron scattering from static hydrogen without exchange. The Schrödinger equation (SE) reduces to a 2D partial differential equation (PDE), which is solved using the finite element method (FEM) [2]. The integral over dφr is done analytically, reducing the integral expression for f(Ω_k) to a 2D integral. Here we extend the method to include the effects of exchange. The SE can be reduced to a pair of 2D coupled PDE's which are again solved by the FEM. The formal expression for f(Ω) consists of two integrals, f^=fd f_e; fd is formally the same integral as the no-exchange f. We have also succeeded in reducing fe to a 2D integral. Results will be presented at the meeting. [1] J. Shertzer and A. Temkin, Phys. Rev. A 63, 062714 (2001). [2] J. Shertzer and J. Botero, Phys. Rev. A 49, 3673 (1994).
Partial wave analyses of J/ψ→γππ and γππ
NASA Astrophysics Data System (ADS)
BES Collaboration; Ablikim, M.; Bai, J. Z.; Ban, Y.; Bian, J. G.; Cai, X.; Chen, H. F.; Chen, H. S.; Chen, H. X.; Chen, J. C.; Chen, Jin; Chen, Y. B.; Chi, S. P.; Chu, Y. P.; Cui, X. Z.; Dai, Y. S.; Diao, L. Y.; Deng, Z. Y.; Dong, Q. F.; Du, S. X.; Fang, J.; Fang, S. S.; Fu, C. D.; Gao, C. S.; Gao, Y. N.; Gu, S. D.; Gu, Y. T.; Guo, Y. N.; Guo, Y. Q.; Guo, Z. J.; Harris, F. A.; He, K. L.; He, M.; Heng, Y. K.; Hu, H. M.; Hu, T.; Huang, G. S.; Huang, X. T.; Ji, X. B.; Jiang, X. S.; Jiang, X. Y.; Jiao, J. B.; Jin, D. P.; Jin, S.; Jin, Yi; Lai, Y. F.; Li, G.; Li, H. B.; Li, H. H.; Li, J.; Li, R. Y.; Li, S. M.; Li, W. D.; Li, W. G.; Li, X. L.; Li, X. N.; Li, X. Q.; Li, Y. L.; Liang, Y. F.; Liao, H. B.; Liu, B. J.; Liu, C. X.; Liu, F.; Liu, Fang; Liu, H. H.; Liu, H. M.; Liu, J.; Liu, J. B.; Liu, J. P.; Liu, Q.; Liu, R. G.; Liu, Z. A.; Lou, Y. C.; Lu, F.; Lu, G. R.; Lu, J. G.; Luo, C. L.; Ma, F. C.; Ma, H. L.; Ma, L. L.; Ma, Q. M.; Ma, X. B.; Mao, Z. P.; Mo, X. H.; Nie, J.; Olsen, S. L.; Peng, H. P.; Ping, R. G.; Qi, N. D.; Qin, H.; Qiu, J. F.; Ren, Z. Y.; Rong, G.; Shan, L. Y.; Shang, L.; Shen, C. P.; Shen, D. L.; Shen, X. Y.; Sheng, H. Y.; Sun, H. S.; Sun, J. F.; Sun, S. S.; Sun, Y. Z.; Sun, Z. J.; Tan, Z. Q.; Tang, X.; Tong, G. L.; Varner, G. S.; Wang, D. Y.; Wang, L.; Wang, L. L.; Wang, L. S.; Wang, M.; Wang, P.; Wang, P. L.; Wang, W. F.; Wang, Y. F.; Wang, Z.; Wang, Z. Y.; Wang, Zhe; Wang, Zheng; Wei, C. L.; Wei, D. H.; Wu, N.; Xia, X. M.; Xie, X. X.; Xu, G. F.; Xu, X. P.; Xu, Y.; Yan, M. L.; Yang, H. X.; Yang, Y. X.; Ye, M. H.; Ye, Y. X.; Yi, Z. Y.; Yu, G. W.; Yuan, C. Z.; Yuan, J. M.; Yuan, Y.; Zang, S. L.; Zeng, Y.; Zeng, Yu; Zhang, B. X.; Zhang, B. Y.; Zhang, C. C.; Zhang, D. H.; Zhang, H. Q.; Zhang, H. Y.; Zhang, J. W.; Zhang, J. Y.; Zhang, S. H.; Zhang, X. M.; Zhang, X. Y.; Zhang, Yiyun; Zhang, Z. P.; Zhao, D. X.; Zhao, J. W.; Zhao, M. G.; Zhao, P. P.; Zhao, W. R.; Zhao, Z. G.; Zheng, H. Q.; Zheng, J. P.; Zheng, Z. P.; Zhou, L.; Zhou, N. F.; Zhu, K. J.; Zhu, Q. M.; Zhu, Y. C.; Zhu, Y. S.; Zhu, Yingchun; Zhu, Z. A.; Zhuang, B. A.; Zhuang, X. A.; Zou, B. S.
2006-11-01
Results are presented on J/ψ radiative decays to ππ and ππ based on a sample of 58M J/ψ events taken with the BES II detector. Partial wave analyses are carried out using the relativistic covariant tensor amplitude method in the 1.0 to 2.3GeV/cππ mass range. There are conspicuous peaks due to the f(1270) and two 0 states in the 1.45 and 1.75 GeV/c mass regions. The first 0 state has a mass of 1466±6±20MeV/c, a width of 108-11+14±25MeV/c, and a branching fraction B(J/ψ→γf(1500)→γππ)=(0.67±0.02±0.30)×10. Spin 0 is strongly preferred over spin 2. The second 0 state peaks at 1765-3+4±13MeV/c with a width of 145±8±69MeV/c. If this 0 is interpreted as coming from f(1710), the ratio of its branching fractions to ππ and KK¯ is 0.41-0.17+0.11.
A partial wave analysis of the decay D0 → KS0π+π-
NASA Astrophysics Data System (ADS)
Albrecht, H.; Ehrlichmann, H.; Hamacher, T.; Hofmann, R. P.; Kirchhoff, T.; Nau, A.; Nowak, S.; Schröder, H.; Schulz, H. D.; Walter, M.; Wurth, R.; Appuhn, R. D.; Hast, C.; Kolanoski, H.; Lange, A.; Lindner, A.; Mankel, R.; Schieber, M.; Siegmund, T.; Spaan, B.; Thurn, H.; Töpfer, D.; Walther, A.; Wegener, D.; Paulini, M.; Reim, K.; Wegener, H.; Mundt, R.; Oest, T.; Reiner, R.; Schmidt-Parzefall, W.; Funk, W.; Stiewe, J.; Werner, S.; Ehret, K.; Hofmann, W.; Hüpper, A.; Khan, S.; Knöpfle, K. T.; Spengler, J.; Britton, D. I.; Charlesworth, C. E. K.; Edwards, K. W.; Hyatt, E. R. F.; Kapitza, H.; Krieger, P.; Macfarlane, D. B.; Patel, P. M.; Prentice, J. D.; Saull, P. R. B.; Tzamariudaki, K.; van de Water, R. G.; Yoon, T.-S.; Reßing, D.; Schmidtler, M.; Schneider, M.; Schubert, K. R.; Strahl, K.; Tamminga, J.; Waldi, R.; Weseler, S.; Kernel, G.; Križan, P.; Križnič, E.; Podobnik, T.; Živko, T.; Balagura, V.; Belyaev, I.; Danilov, M.; Droutskoy, A.; Golutvin, A.; Gorelov, I.; Kostina, G.; Lubimov, V.; Murat, P.; Pakhlov, P.; Ratnikov, F.; Semenov, S.; Shibaev, V.; Soloshenko, V.; Tichomirov, I.; Zaitsev, Yu.; Argus Collaboration
1993-07-01
Using the ARGUS detector at the DORIS-II electron-positron storage ring at DESY, we have investigated the exclusive decay D ∗+ → D 0π +, D 0 → K S0π +π -. From a partial wave analysis of the KS0π+π- system we find that (71.8± 4.2 ± 3.0)% are D 0 → K ∗-π + and (22.7 ± 3.2 ± 0.9)% are D 0 → overlineK0ϱ 0 with a relative phase of (-137 ± 7 ± 3)° between the channels. The remaining fraction can be described by several channels involving excited resonances, but not by a three-body phase space decay, thus giving first evidence for D0 decays into K 0∗(1430) -π +, overlineK0 f 0(1975), overlineK0 f 2(1270) , and overlineK0 f 0(1400) .
Spreading speed and travelling wave solutions of a partially sedentary population
NASA Astrophysics Data System (ADS)
Volkov, Darko; Lui, Roger
2007-12-01
In this paper, we extend the population genetics model of Weinberger (1978, Asymptotic behavior of a model in population genetics. Nonlinear Partial Differential Equations and Applications (J. Chadam ed.). Lecture Notes in Mathematics, vol. 648. New York: Springer, pp. 47-98.) to the case where a fraction of the population does not migrate after the selection process. Mathematically, we study the asymptotic behaviour of solutions to the recursion un+1 = Qg[un], where ... In the above definition of Qg, K is a probability density function and f behaves qualitatively like the Beverton-Holt function. Under some appropriate conditions on K and f, we show that for each unit vector{xi} [isin] Rd, there exists a c*g({xi}) which has an explicit formula and is the spreading speed of Qg in the direction{xi} . We also show that for each c [≥] c*g({xi}), there exists a travelling wave solution in the direction{xi} which is continuous if gf '(0) [≤] 1.
The Scientific Potential of Space-Based Gravitational Wave Detectors
NASA Astrophysics Data System (ADS)
Gair, Jonathan R.
The millihertz gravitational wave band can only be accessed with a space-based interferometer, but it is one of the richest in potential sources. Observations in this band have amazing scientific potential. The mergers between massive black holes with mass in the range 104-107M_{⊙}, which are expected to occur following the mergers of their host galaxies, produce strong millihertz gravitational radiation. Observations of these systems will trace the hierarchical assembly of structure in the Universe in a mass range that is very difficult to probe electromagnetically. Stellar mass compact objects falling into such black holes in the centres of galaxies generate detectable gravitational radiation for several years prior to the final plunge and merger with the central black hole. Measurements of these systems offer an unprecedented opportunity to probe the predictions of general relativity in the strong-field and dynamical regime. Millihertz gravitational waves are also generated by millions of ultra-compact binaries in the Milky Way, providing a new way to probe galactic stellar populations. ESA has recognised this great scientific potential by selecting The Gravitational Universe as its theme for the L3 large satellite mission, scheduled for launch in ˜ 2034. In this article we will review the likely sources for millihertz gravitational wave detectors and describe the wide applications that observations of these sources could have for astrophysics, cosmology and fundamental physics.
Prediction model of sinoatrial node field potential using high order partial least squares.
Feng, Yu; Cao, Hui; Zhang, Yanbin
2015-01-01
High order partial least squares (HOPLS) is a novel data processing method. It is highly suitable for building prediction model which has tensor input and output. The objective of this study is to build a prediction model of the relationship between sinoatrial node field potential and high glucose using HOPLS. The three sub-signals of the sinoatrial node field potential made up the model's input. The concentration and the actuation duration of high glucose made up the model's output. The results showed that on the premise of predicting two dimensional variables, HOPLS had the same predictive ability and a lower dispersion degree compared with partial least squares (PLS).
Resolving Difficulties of a Single-Channel Partial-Wave Analysis
NASA Astrophysics Data System (ADS)
Hunt, Brian; Manley, D. Mark
2016-03-01
The goal of our research is to determine better the properties of nucleon resonances using techniques of a global multichannel partial-wave analysis. Currently, many predicted resonances have not been found, while the properties of several known resonances are relatively uncertain. To resolve these issues, one must analyze many different reactions in a multichannel fit. Other groups generally approach this problem by generating an energy-dependent fit from the start. This is a fit where all channels are analyzed together. The method is powerful, but due to the complex nature of resonances, certain model-dependent assumptions have to be introduced from the start. The current work tries to resolve these issues by first generating single-energy solutions in which experimental data are analyzed in narrow energy bins. The single-energy solutions can then be used to constrain the energy-dependent solution in a comparatively unbiased manner. Our work focuses on adding three new single-energy solutions into the global fit. These reactions are γp --> ηp , γn --> ηn , and γp -->K+ Λ . During this talk, I will discuss the difficulties of this approach, our methods to overcome these difficulties, and a few preliminary results. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Medium Energy Nuclear Physics, under Award Nos. DE-FG02-01ER41194 and DE-SC0014323 and by the Kent State University Department of Physics.
NASA Astrophysics Data System (ADS)
Zhang, Di; Graff, Taylor; Crawford, Susan; Subramanian, Hariharan; Thompson, Sebastian; Derbas, Justin R.; Lyengar, Radha; Roy, Hemant K.; Brendler, Charles B.; Backman, Vadim
2016-02-01
Prostate Cancer (PC) is the second leading cause of cancer deaths in American men. While prostate specific antigen (PSA) test has been widely used for screening PC, >60% of the PSA detected cancers are indolent, leading to unnecessary clinical interventions. An alternative approach, active surveillance (AS), also suffer from high expense, discomfort and complications associated with repeat biopsies (every 1-3 years), limiting its acceptance. Hence, a technique that can differentiate indolent from aggressive PC would attenuate the harms from over-treatment. Combining microscopy with spectroscopy, our group has developed partial wave spectroscopic (PWS) microscopy, which can quantify intracellular nanoscale organizations (e.g. chromatin structures) that are not accessible by conventional microscopy. PWS microscopy has previously been shown to predict the risk of cancer in seven different organs (N ~ 800 patients). Herein we use PWS measurement of label-free histologically-normal prostatic epithelium to distinguish indolent from aggressive PC and predict PC risk. Our results from 38 men with low-grade PC indicated that there is a significant increase in progressors compared to non-progressors (p=0.002, effect size=110%, AUC=0.80, sensitivity=88% and specificity=72%), while the baseline clinical characteristics were not significantly different. We further improved the diagnostic power by performing nuclei-specific measurements using an automated system that separates in real-time the cell nuclei from the remaining prostate epithelium. In the long term, we envision that the PWS based prognostication can be coupled with AS without any change to the current procedure to mitigate the harms caused by over-treatment.
NASA Astrophysics Data System (ADS)
Li, Jia; Chang, Liping; Chen, Feinan
2016-12-01
Based on the first-order Born approximation, the correlation between intensity fluctuations is derived for a partially coherent, electromagnetic plane wave scattering from a spatially quasi-homogeneous medium. Young's pinholes are utilized to control the degree of coherence of the incident field. For the electromagnetic scattering case, it is shown that the CIF of the scattered field strongly depends on the degree of polarization of the incident wave, Young's pinhole parameter, effective radius and correlation length of the medium. The influences of these parameters on the CIF distributions are revealed by numerical calculations.
NASA Astrophysics Data System (ADS)
Chrysos, Michael
2016-03-01
Relying on a simple analytic two-atom model in which the anisotropy of the interaction dipole polarizability obeys an inverse power law as a function of separation, we offer mathematical and numerical evidence that, in a monoatomic gas, the free-free Raman spectrum for a collisional pair of two different isotopes, a-a', may vastly differ from that for a-a. This result is obtained even if a and a' are assumed to have the same mass and zero nuclear spin and even if a-a and a-a' are subject to the same interaction polarizability and potential. The mechanism responsible for this effect is inherent in the parity of the partial-wave rotational quantum number J: given that the contribution of each partial wave to the Raman cross section is controlled by a polarizability-transition matrix-element and that each of those matrix-elements has a radial component with a magnitude slightly smaller than that of the preceding partial wave, a deficit which disfavors the odd-numbered waves is accumulated upon summing over J. In the far high-frequency wing, this deficit tends to generate spectral intensities for a-a' about half as great as the a-a ones, a tendency which becomes all the more effective as temperature is decreased. We show for instance that, for the spectral branch ΔJ = 2, the fractional difference between the free-free differential cross sections for a-a and a-a' is /1 2 /( 1 - x2 ) 3 1 + 3 x 4 , with x = √{ E / E ' } (E (E') being the initial (final) state energy of the pair and E' - E = hcν (ν > 0)). Remarkably, this quantity is zero at ν ≈ 0 but goes to /1 2 for ν ≫ 0. For ΔJ = 0, analogous conclusions may be drawn from the expression ( 1 + /ln ( 1+x/1-x ) 2 arctan x ) - 1 .
Grozdanov, T.P.; Andric, L.; McCarroll, R.
2006-03-07
We investigate the use of complex absorbing potentials for the calculation of partial cross sections in multichannel photofragmentation processes. An exactly solvable, coupled-two-channel problem involving square-well potentials is used to compare the performance of various types of absorbing potentials. Special emphasis is given to the near-threshold regions and the conditions under which the numerical results are able to reproduce the Wigner threshold laws. It was found that singular, transmission-free absorbing potentials perform better than those of power or polynomial form.
Marie, James John
2006-05-01
The JETSET experiment (PS202) conducted at CERN was designed to search for gluonic resonances in the mass range between 2.14 and 2.43 GeV/c^{2} using the channel, p$\\bar{p}$→ΦΦ→4K+/-. This channel is OZI suppressed, thus any observed enhancement of the cross section above a level consistent with the OZI rule could indicate possible resonating gluonic degrees of freedom. In fact, the measured cross section is two orders of magnitude larger than the OZI prediction and shows an enhancement centered near 2.2 GeV/c^{2} of width 50-100 MeV/c^{2}. A partial wave analysis (PWA) has been conducted in order to search for the dominant partial waves. The formalism and methods of this PWA will be fully developed. This analysis has revealed the dominance of J^{pc} = 2^{++} together with a significant J^{pc} = 4^{++} component. Because the Φ resonance is only 4 MeV wide, the PWA is relatively insensitive to the presence of competing channels coupling to the 4K^{±} final state. The partial wave analysis was
Li, Jia; Zhang, Hongchao; Ni, Chenyin; Shen, Zhonghua
2013-06-20
This research focuses on analyzing the frequency characteristics of ultrasonic waves induced by a partially closed surface-breaking crack. When acoustic waves interact with the crack, transmission, reflection, and mode conversions occur and the frequency characteristics of signals perform obvious changes. A pulsed laser line source is used to generate ultrasonic waves in the sample with a partially closed surface-breaking crack, and one can see how the frequency characteristics of detected signals change as the pulsed laser beam scans across the sample surface. The optical deflection beam method is developed to detect the ultrasonic signals experimentally. The fast Fourier transform (FFT) is used to analyze the time-domain data, and the FFT data are visualized by a B-scan plot. A clear disruption in the B-scan can be observed when the laser beam illuminates directly onto the crack, which is due to the changes of frequency characteristics induced by the partially closed crack. A frequency-domain B-scan of numerical simulation results is presented, and the clear disruption can also be observed clearly.
Mynard, Jonathan P; Smolich, Joseph J
2014-08-01
Controversy exists about whether one-dimensional wave theory can explain the "self-canceling" waves that accompany the diastolic pressure decay and discharge of the arterial reservoir. Although it has been proposed that reservoir and wave effects be treated as separate phenomena, thus avoiding the issue of self-canceling waves, we have argued that reservoir effects are a phenomenological and mathematical subset of wave effects. However, a complete wave-based explanation of self-canceling diastolic expansion (pressure-decreasing) waves has not yet been advanced. These waves are present in the forward and backward components of arterial pressure and flow (P ± and Q ±, respectively), which are calculated by integrating incremental pressure and flow changes (dP ± and dQ ±, respectively). While the integration constants for this calculation have previously been considered arbitrary, we showed that physiologically meaningful constants can be obtained by identifying "undisturbed pressure" as mean circulatory pressure. Using a series of numeric experiments, absolute P ± and Q ± values were shown to represent "wave potential," gradients of which produce propagating wavefronts. With the aid of a "one-dimensional windkessel," we showed how wave theory predicts discharge of the arterial reservoir. Simulated data, along with hemodynamic recordings in seven sheep, suggested that self-canceling diastolic waves arise from repeated and diffuse reflection of the late systolic forward expansion wave throughout the arterial system and at the closed aortic valve, along with progressive leakage of wave potential from the conduit arteries. The combination of wave and wave potential concepts leads to a comprehensive one-dimensional (i.e., wave-based) explanation of arterial hemodynamics, including the diastolic pressure decay.
Van Strien, Jan W.; Isbell, Lynne A.
2017-01-01
Studies of event-related potentials in humans have established larger early posterior negativity (EPN) in response to pictures depicting snakes than to pictures depicting other creatures. Ethological research has recently shown that macaques and wild vervet monkeys respond strongly to partially exposed snake models and scale patterns on the snake skin. Here, we examined whether snake skin patterns and partially exposed snakes elicit a larger EPN in humans. In Task 1, we employed pictures with close-ups of snake skins, lizard skins, and bird plumage. In task 2, we employed pictures of partially exposed snakes, lizards, and birds. Participants watched a random rapid serial visual presentation of these pictures. The EPN was scored as the mean activity (225–300 ms after picture onset) at occipital and parieto-occipital electrodes. Consistent with previous studies, and with the Snake Detection Theory, the EPN was significantly larger for snake skin pictures than for lizard skin and bird plumage pictures, and for lizard skin pictures than for bird plumage pictures. Likewise, the EPN was larger for partially exposed snakes than for partially exposed lizards and birds. The results suggest that the EPN snake effect is partly driven by snake skin scale patterns which are otherwise rare in nature. PMID:28387376
Van Strien, Jan W; Isbell, Lynne A
2017-04-07
Studies of event-related potentials in humans have established larger early posterior negativity (EPN) in response to pictures depicting snakes than to pictures depicting other creatures. Ethological research has recently shown that macaques and wild vervet monkeys respond strongly to partially exposed snake models and scale patterns on the snake skin. Here, we examined whether snake skin patterns and partially exposed snakes elicit a larger EPN in humans. In Task 1, we employed pictures with close-ups of snake skins, lizard skins, and bird plumage. In task 2, we employed pictures of partially exposed snakes, lizards, and birds. Participants watched a random rapid serial visual presentation of these pictures. The EPN was scored as the mean activity (225-300 ms after picture onset) at occipital and parieto-occipital electrodes. Consistent with previous studies, and with the Snake Detection Theory, the EPN was significantly larger for snake skin pictures than for lizard skin and bird plumage pictures, and for lizard skin pictures than for bird plumage pictures. Likewise, the EPN was larger for partially exposed snakes than for partially exposed lizards and birds. The results suggest that the EPN snake effect is partly driven by snake skin scale patterns which are otherwise rare in nature.
Kim, Choong-Ki; Toft, Jodie E; Papenfus, Michael; Verutes, Gregory; Guerry, Anne D; Ruckelshaus, Marry H; Arkema, Katie K; Guannel, Gregory; Wood, Spencer A; Bernhardt, Joanna R; Tallis, Heather; Plummer, Mark L; Halpern, Benjamin S; Pinsky, Malin L; Beck, Michael W; Chan, Francis; Chan, Kai M A; Levin, Phil S; Polasky, Stephen
2012-01-01
Many hope that ocean waves will be a source for clean, safe, reliable and affordable energy, yet wave energy conversion facilities may affect marine ecosystems through a variety of mechanisms, including competition with other human uses. We developed a decision-support tool to assist siting wave energy facilities, which allows the user to balance the need for profitability of the facilities with the need to minimize conflicts with other ocean uses. Our wave energy model quantifies harvestable wave energy and evaluates the net present value (NPV) of a wave energy facility based on a capital investment analysis. The model has a flexible framework and can be easily applied to wave energy projects at local, regional, and global scales. We applied the model and compatibility analysis on the west coast of Vancouver Island, British Columbia, Canada to provide information for ongoing marine spatial planning, including potential wave energy projects. In particular, we conducted a spatial overlap analysis with a variety of existing uses and ecological characteristics, and a quantitative compatibility analysis with commercial fisheries data. We found that wave power and harvestable wave energy gradually increase offshore as wave conditions intensify. However, areas with high economic potential for wave energy facilities were closer to cable landing points because of the cost of bringing energy ashore and thus in nearshore areas that support a number of different human uses. We show that the maximum combined economic benefit from wave energy and other uses is likely to be realized if wave energy facilities are sited in areas that maximize wave energy NPV and minimize conflict with existing ocean uses. Our tools will help decision-makers explore alternative locations for wave energy facilities by mapping expected wave energy NPV and helping to identify sites that provide maximal returns yet avoid spatial competition with existing ocean uses.
Kim, Choong-Ki; Toft, Jodie E.; Papenfus, Michael; Verutes, Gregory; Guerry, Anne D.; Ruckelshaus, Marry H.; Arkema, Katie K.; Guannel, Gregory; Wood, Spencer A.; Bernhardt, Joanna R.; Tallis, Heather; Plummer, Mark L.; Halpern, Benjamin S.; Pinsky, Malin L.; Beck, Michael W.; Chan, Francis; Chan, Kai M. A.; Levin, Phil S.; Polasky, Stephen
2012-01-01
Many hope that ocean waves will be a source for clean, safe, reliable and affordable energy, yet wave energy conversion facilities may affect marine ecosystems through a variety of mechanisms, including competition with other human uses. We developed a decision-support tool to assist siting wave energy facilities, which allows the user to balance the need for profitability of the facilities with the need to minimize conflicts with other ocean uses. Our wave energy model quantifies harvestable wave energy and evaluates the net present value (NPV) of a wave energy facility based on a capital investment analysis. The model has a flexible framework and can be easily applied to wave energy projects at local, regional, and global scales. We applied the model and compatibility analysis on the west coast of Vancouver Island, British Columbia, Canada to provide information for ongoing marine spatial planning, including potential wave energy projects. In particular, we conducted a spatial overlap analysis with a variety of existing uses and ecological characteristics, and a quantitative compatibility analysis with commercial fisheries data. We found that wave power and harvestable wave energy gradually increase offshore as wave conditions intensify. However, areas with high economic potential for wave energy facilities were closer to cable landing points because of the cost of bringing energy ashore and thus in nearshore areas that support a number of different human uses. We show that the maximum combined economic benefit from wave energy and other uses is likely to be realized if wave energy facilities are sited in areas that maximize wave energy NPV and minimize conflict with existing ocean uses. Our tools will help decision-makers explore alternative locations for wave energy facilities by mapping expected wave energy NPV and helping to identify sites that provide maximal returns yet avoid spatial competition with existing ocean uses. PMID:23144824
NASA Astrophysics Data System (ADS)
Martínez-Gómez, David; Soler, Roberto; Terradas, Jaume
2017-03-01
The presence of neutral species in a plasma has been shown to greatly affect the properties of magnetohydrodynamic waves. For instance, the interaction between ions and neutrals through momentum transfer collisions causes the damping of Alfvén waves and alters their oscillation frequency and phase speed. When the collision frequencies are larger than the frequency of the waves, single-fluid magnetohydrodynamic approximations can accurately describe the effects of partial ionization, since there is a strong coupling between the various species. However, at higher frequencies, the single-fluid models are not applicable and more complex approaches are required. Here, we use a five-fluid model with three ionized and two neutral components, which takes into consideration Hall’s current and Ohm’s diffusion in addition to the friction due to collisions between different species. We apply our model to plasmas composed of hydrogen and helium, and allow the ionization degree to be arbitrary. By analyzing the corresponding dispersion relation and numerical simulations, we study the properties of small-amplitude perturbations. We discuss the effect of momentum transfer collisions on the ion-cyclotron resonances and compare the importance of magnetic resistivity, and ion–neutral and ion–ion collisions on the wave damping at various frequency ranges. Applications to partially ionized plasmas of the solar atmosphere are performed.
The Propagation of Slow Wave Potentials in Pea Epicotyls.
Stahlberg, R.; Cosgrove, D. J.
1997-01-01
Slow wave potentials are considered to be electric long-distance signals specific for plants, although there are conflicting ideas about a chemical, electrical, or hydraulic mode of propagation. These ideas were tested by comparing the propagation of hydraulic and electric signals in epicotyls of pea (Pisum sativum L). A hydraulic signal in the form of a defined step increase in xylem pressure (Px) was applied to the root of intact seedlings and propagated nearly instantly through the epicotyl axis while its amplitude decreased with distance from the pressure chamber. This decremental propagation was caused by a leaky xylem and created an axial Px gradient in the epicotyl. Simultaneously along the epicotyl surface, depolarizations appeared with lag times that increased acropetally with distance from the pressure chamber from 5 s to 3 min. When measured at a constant distance, the lag times increased as the size of the applied pressure steps decreased. We conclude that the Px gradient in the epicotyl caused local depolarizations with acropetally increasing lag times, which have the appearance of an electric signal propagating with a rate of 20 to 30 mm min-1. This static description of the slow wave potentials challenges its traditional classification as a propagating electric signal. PMID:12223601
Three-dimensional rogue waves in nonstationary parabolic potentials.
Yan, Zhenya; Konotop, V V; Akhmediev, N
2010-09-01
Using symmetry analysis we systematically present a higher-dimensional similarity transformation reducing the (3+1) -dimensional inhomogeneous nonlinear Schrödinger (NLS) equation with variable coefficients and parabolic potential to the (1+1) -dimensional NLS equation with constant coefficients. This transformation allows us to relate certain class of localized exact solutions of the (3+1) -dimensional case to the variety of solutions of integrable NLS equation of the (1+1) -dimensional case. As an example, we illustrated our technique using two lowest-order rational solutions of the NLS equation as seeding functions to obtain rogue wavelike solutions localized in three dimensions that have complicated evolution in time including interactions between two time-dependent rogue wave solutions. The obtained three-dimensional rogue wavelike solutions may raise the possibility of relative experiments and potential applications in nonlinear optics and Bose-Einstein condensates.
Three-dimensional rogue waves in nonstationary parabolic potentials
Yan Zhenya; Konotop, V. V.; Akhmediev, N.
2010-09-15
Using symmetry analysis we systematically present a higher-dimensional similarity transformation reducing the (3+1)-dimensional inhomogeneous nonlinear Schroedinger (NLS) equation with variable coefficients and parabolic potential to the (1+1)-dimensional NLS equation with constant coefficients. This transformation allows us to relate certain class of localized exact solutions of the (3+1)-dimensional case to the variety of solutions of integrable NLS equation of the (1+1)-dimensional case. As an example, we illustrated our technique using two lowest-order rational solutions of the NLS equation as seeding functions to obtain rogue wavelike solutions localized in three dimensions that have complicated evolution in time including interactions between two time-dependent rogue wave solutions. The obtained three-dimensional rogue wavelike solutions may raise the possibility of relative experiments and potential applications in nonlinear optics and Bose-Einstein condensates.
NASA Astrophysics Data System (ADS)
Lee, Myoung-Jae; Jung, Young-Dae
2017-02-01
High frequency electrostatic wave propagation in a dense and semi-bounded electron quantum plasma is investigated with consideration of the Bohm potential. The dispersion relation for the surface mode of quantum plasma is derived and numerically analyzed. We found that the quantum effect enhances the frequency of the wave especially in the high wave number regime. However, the frequency of surface wave is found to be always lower than that of the bulk wave for the same quantum wave number. The group velocity of the surface wave for various quantum wave number is also obtained.
NASA Astrophysics Data System (ADS)
Tao, Yinghua; Speidel, Michael; Szczykutowicz, Timothy; Chen, Guang-Hong
2014-03-01
In recent years, there have been several findings regarding CT number variations (partial scan artifact or PSA) across time in dynamic myocardial perfusion studies with short scan gated reconstruction. These variations are correlated with the view angle range corresponding to the short scan acquisition for a given cardiac phase, which can vary from one cardiac cycle to another due to the asynchrony between heart rate and gantry rotation speed. In this study, we investigate several potential causes of PSA, including noise, beam hardening and scatter, using numerical simulations. In addition, we investigate partial scan artifact in a single source 64-slice diagnostic CT scanner in vivo data sets, and report its effect on perfusion analysis. Results indicated that among all three factors investigated, scatter can cause obvious partial scan artifact in dynamic myocardial perfusion imaging. Further, scatter is a low frequency phenomenon and is not heavily dependent on the changing contrasts, as both the frequency method and the virtual scan method are effective in reducing partial scan artifact. However, PSA does not necessarily lead to different blood volume maps compared to the full scan, because these maps are usually generated with a curve fitting procedure.
NASA Astrophysics Data System (ADS)
Maneva, Y. G.; Poedts, S.; Alvarez Laguna, A.; Lani, A.
2016-12-01
Ion-neutral interactions play crucial role in the energetics and dynamics of the partially ionized solar chromosphere. To study the effect of neutrals for the evolution of the chromospheric plasma, including the transport coefficients, chemical reactions and possible contribution to wave damping and absorption, we have developed a multi-fluid simulation tool, which considers ionization and recombination processes in gravitationally stratified magnetized collisional media. Recent works have suggested that the vastly dominant neutrals might over-damp Alfvén waves in the chromosphere, thus absorbing their energy closer to the solar surface and reducing the contribution of Alfvén waves generated by the photospheric drivers to the coronal heating problem. In this study we have driven slow magnetosonic and Alfvén waves at the photosphere and have followed their evolution through the chromosphere towards the transition region. We have investigated the wave energy transfer related to shock formation, wave absorption and mode conversion in the gravitationally stratified media, as well as have the distribution of Poynting flux. Our two-fluid model consists of resistive MHD electrons and ions, which are chemically and collisionally coupled to a separate fluid population of neutral hydrogen. The model takes into account Coulomb collisions, anisotropic heat flux determined by Braginskii's transport coefficients, as well as impact ionization and radiative recombination. The initial state represents gravitationally stratified temperature and density profiles, which satisfy hydrostatic chemical equilibrium, except for the Lorentz force associated with the external magnetic field. We study the effects of the initial driver's amplitude and period on the related plasma energization, as well as the wave-induced changes in ionization and recombination.
Wang, Minghao; Yuan, Xiuhua; Ma, Donglin
2017-04-01
Nonuniformly correlated partially coherent beams (PCBs) have extraordinary propagation properties, making it possible to further improve the performance of free-space optical communications. In this paper, a series of PCBs with varying degrees of coherence in the radial direction, academically called radial partially coherent beams (RPCBs), are considered. RPCBs with arbitrary coherence distributions can be created by adjusting the amplitude profile of a spatial modulation function imposed on a uniformly correlated phase screen. Since RPCBs cannot be well characterized by the coherence length, a modulation depth factor is introduced as an indicator of the overall distribution of coherence. By wave optics simulation, free-space and atmospheric propagation properties of RPCBs with (inverse) Gaussian and super-Gaussian coherence distributions are examined in comparison with conventional Gaussian Schell-model beams. Furthermore, the impacts of varying central coherent areas are studied. Simulation results reveal that under comparable overall coherence, beams with a highly coherent core and a less coherent margin exhibit a smaller beam spread and greater on-axis intensity, which is mainly due to the self-focusing phenomenon right after the beam exits the transmitter. Particularly, those RPCBs with super-Gaussian coherence distributions will repeatedly focus during propagation, resulting in even greater intensities. Additionally, RPCBs also have a considerable ability to reduce scintillation. And it is demonstrated that those properties have made RPCBs very effective in improving the mean signal-to-noise ratio of small optical receivers, especially in relatively short, weakly fluctuating links.
Partially coherent fundamental Gaussian wave generated by a fluctuating planar current source.
Seshadri, S R
2010-06-01
The propagation characteristics of a spatially localized electromagnetic wave produced by a planar current source of different states of spatial coherence are analyzed by the use of a Gaussian Schell-model source. A linearly polarized fundamental electromagnetic Gaussian wave with the electric field perpendicular to the direction of propagation is treated. The effects of the degree of coherence of the source distribution on the radiation intensity distribution and the total radiated power are determined.
Conservation laws of wave action and potential enstrophy for Rossby waves in a stratified atmosphere
NASA Technical Reports Server (NTRS)
Straus, D. M.
1983-01-01
The evolution of wave energy, enstrophy, and wave motion for atmospheric Rossby waves in a variable mean flow are discussed from a theoretical and pedagogic standpoint. In the absence of mean flow gradients, the wave energy density satisfies a local conservation law, with the appropriate flow velocity being the group velocity. In the presence of mean flow variations, wave energy is not conserved, but wave action is, provided the mean flow is independent of longitude. Wave enstrophy is conserved for arbitrary variations of the mean flow. Connections with Eiiassen-Palm flux are also discussed.
Conservation laws of wave action and potential enstrophy for Rossby waves in a stratified atmosphere
NASA Technical Reports Server (NTRS)
Straus, D. M.
1983-01-01
The evolution of wave energy, enstrophy, and wave motion for atmospheric Rossby waves in a variable mean flow are discussed from a theoretical and pedagogic standpoint. In the absence of mean flow gradients, the wave energy density satisfies a local conservation law, with the appropriate flow velocity being the group velocity. In the presence of mean flow variations, wave energy is not conserved, but wave action is, provided the mean flow is independent of longitude. Wave enstrophy is conserved for arbitrary variations of the mean flow. Connections with Eiiassen-Palm flux are also discussed.
Conservation laws of wave action and potential enstrophy for Rossby waves in a stratified atmosphere
NASA Technical Reports Server (NTRS)
Straus, D. M.
1983-01-01
The evolution of wave energy, enstrophy, and wave motion for atmospheric Rossby waves in a variable mean flow are discussed from a theoretical and pedagogic standpoint. In the absence of mean flow gradients, the wave energy density satisfies a local conservation law, with the appropriate flow velocity being the group velocity. In the presence of mean flow variations, wave energy is not conserved, but wave action is, provided the mean flow is independent of longitude. Wave enstrophy is conserved for arbitrary variations of the mean flow. Connections with Eliassen-Palm flux are also discussed.
NASA Astrophysics Data System (ADS)
Altshuler, Gennady; Manor, Ofer
2016-07-01
We use both theory and experiment to study the response of thin and free films of a partially wetting liquid to a MHz vibration, propagating in the solid substrate in the form of a Rayleigh surface acoustic wave (SAW). We generalise the previous theory for the response of a thin fully wetting liquid film to a SAW by including the presence of a small but finite three phase contact angle between the liquid and the solid. The SAW in the solid invokes a convective drift of mass in the liquid and leaks sound waves. The dynamics of a film that is too thin to support the accumulation of the sound wave leakage is governed by a balance between the drift and capillary stress alone. We use theory to demonstrate that a partially wetting liquid film, supporting a weak capillary stress, will spread along the path of the SAW. A partially wetting film, supporting an appreciable capillary stress, will however undergo a concurrent dynamic wetting and dewetting at the front and the rear, respectively, such that the film will displace, rather than spread, along the path of the SAW. The result of the theory for a weak capillary stress is in agreement with the previous experimental and theoretical studies on the response of thin silicon oil films to a propagating SAW. No corresponding previous results exist for the case of an appreciable capillary stress. We thus complement the large capillary limit of our theory by undertaking an experimental procedure where we explore the response of films of water and a surfactant solutions to a MHz SAW, which is found to be in qualitative agreement with the theory at this limit.
Djedovic, Gabriel; Kamelger, Florian Stefan; Jeschke, Johannes; Piza-Katzer, Hildegunde
2014-01-01
Extracorporeal shock wave therapy (ESWT) enhances tissue vascularization and neoangiogenesis. Recent animal studies showed improved soft tissue regeneration using ESWT. In most cases, deep partial-thickness burns require skin grafting; the outcome is often unsatisfactory in function and aesthetic appearance. The aim of this study was to demonstrate the effect of ESWT on skin regeneration after deep partial-thickness burns. Under general anesthesia, two standardized deep partial-thickness burns were induced on the back of 30 male Wistar rats. Immediately after the burn, ESWT was given to rats of group 1 (N = 15), but not to group 2 (N = 15). On days 5, 10, and 15, five rats of each group were analyzed. Reepithelialization rate was defined, perfusion units were measured, and histological analysis was performed. Digital photography was used for visual documentation. A wound score system was used. ESWT enhanced the percentage of wound closure in group 1 as compared to group 2 (P < 0.05). The reepithelialization rate was improved significantly on day 15 (P < 0.05). The wound score showed a significant increase in the ESWT group. ESWT improves skin regeneration of deep partial-thickness burns in rats. It may be a suitable and cost effective treatment alternative in this type of burn wounds in the future.
Kamelger, Florian Stefan; Jeschke, Johannes; Piza-Katzer, Hildegunde
2014-01-01
Extracorporeal shock wave therapy (ESWT) enhances tissue vascularization and neoangiogenesis. Recent animal studies showed improved soft tissue regeneration using ESWT. In most cases, deep partial-thickness burns require skin grafting; the outcome is often unsatisfactory in function and aesthetic appearance. The aim of this study was to demonstrate the effect of ESWT on skin regeneration after deep partial-thickness burns. Under general anesthesia, two standardized deep partial-thickness burns were induced on the back of 30 male Wistar rats. Immediately after the burn, ESWT was given to rats of group 1 (N = 15), but not to group 2 (N = 15). On days 5, 10, and 15, five rats of each group were analyzed. Reepithelialization rate was defined, perfusion units were measured, and histological analysis was performed. Digital photography was used for visual documentation. A wound score system was used. ESWT enhanced the percentage of wound closure in group 1 as compared to group 2 (P < 0.05). The reepithelialization rate was improved significantly on day 15 (P < 0.05). The wound score showed a significant increase in the ESWT group. ESWT improves skin regeneration of deep partial-thickness burns in rats. It may be a suitable and cost effective treatment alternative in this type of burn wounds in the future. PMID:25431664
Henao-Escobar, W; Domínguez-Renedo, O; Alonso-Lomillo, M A; Arcos-Martínez, M J
2015-10-01
This work presents the simultaneous determination of cadaverine, histamine, putrescine and tyramine by square wave voltammetry using a boron-doped diamond electrode. A multivariate calibration method based on partial least square regressions has allowed the resolution of the very high overlapped voltammetric signals obtained for the analyzed biogenic amines. Prediction errors lower than 9% have been obtained when concentration of quaternary mixtures were calculated. The developed procedure has been applied in the analysis of ham samples, which results are in good agreement with those obtained using the standard HPLC method. Copyright © 2015 Elsevier B.V. All rights reserved.
Cut-off wavenumber of Alfvén waves in partially ionized plasmas of the solar atmosphere
NASA Astrophysics Data System (ADS)
Zaqarashvili, T. V.; Carbonell, M.; Ballester, J. L.; Khodachenko, M. L.
2012-08-01
Context. Alfvén wave dynamics in partially ionized plasmas of the solar atmosphere shows that there is indeed a cut-off wavenumber, i.e. the Alfvén waves with wavenumbers higher than the cut-off value are evanescent. The cut-off wavenumber appears in single-fluid magnetohydrodynamic (MHD) approximation but it is absent in a multi-fluid approach. Up to now, an explanation for the existence of the cut-off wavenumber is still missing. Aims: The aim of this paper is to point out the reason for the appearance of a cut-off wavenumber in single-fluid MHD. Methods: Beginning with three-fluid equations (with electrons, protons and neutral hydrogen atoms), we performed consecutive approximations until we obtained the usual single-fluid description. We solved the dispersion relation of linear Alfvén waves at each step and sought the approximation responsible of the cut-off wavenumber appearance. Results: We have found that neglecting inertial terms significantly reduces the real part of the Alfvén frequency although it never becomes zero. Therefore, the cut-off wavenumber does not exist at this stage. However, when the inertial terms together with the Hall term in the induction equation are neglected, the real part of the Alfvén frequency becomes zero. Conclusions: The appearance of a cut-off wavenumber, when Alfvén waves in partially ionized regions of the solar atmosphere are studied, is the result of neglecting inertial and Hall terms, therefore it has no physical origin.
Assessing the standard Molybdenum projector augmented wave VASP potentials
Mattsson, Ann E.
2014-07-01
Density Functional Theory (DFT) based Equation of State (EOS) construction is a prominent part of Sandia’s capabilities to support engineering sciences. This capability is based on augmenting experimental data with information gained from computational investigations, especially in those parts of the phase space where experimental data is hard, dangerous, or expensive to obtain. A key part of the success of the Sandia approach is the fundamental science work supporting the computational capability. Not only does this work enhance the capability to perform highly accurate calculations but it also provides crucial insight into the limitations of the computational tools, providing high confidence in the results even where results cannot be, or have not yet been, validated by experimental data. This report concerns the key ingredient of projector augmented-wave (PAW) potentials for use in pseudo-potential computational codes. Using the tools discussed in SAND2012-7389 we assess the standard Vienna Ab-initio Simulation Package (VASP) PAWs for Molybdenum.
Salgado, Carlos W.; Weygand, Dennis P.
2014-04-01
Meson spectroscopy is going through a revival with the advent of high statistics experiments and new advances in the theoretical predictions. The Constituent Quark Model (CQM) is finally being expanded considering more basic principles of field theory and using discrete calculations of Quantum Chromodynamics (lattice QCD). These new calculations are approaching predictive power for the spectrum of hadronic resonances and decay modes. It will be the task of the new experiments to extract the meson spectrum from the data and compare with those predictions. The goal of this report is to describe one particular technique for extracting resonance information from multiparticle final states. The technique described here, partial wave analysis based on the helicity formalism, has been used at Brookhaven National Laboratory (BNL) using pion beams, and Jefferson Laboratory (Jlab) using photon beams. In particular this report broaden this technique to include production experiments using linearly polarized real photons or quasi-real photons. This article is of a didactical nature. We describe the process of analysis, detailing assumptions and formalisms, and is directed towards people interested in starting partial wave analysis.
NASA Astrophysics Data System (ADS)
Codina, R.; Ambrosini, D.
2017-06-01
For the last few decades, the effects of blast loading on structures have been studied by many researchers around the world. Explosions can be caused by events such as industrial accidents, military conflicts or terrorist attacks. Urban centers have been prone to various threats including car bombs, suicide attacks, and improvised explosive devices. Partially vented constructions subjected to external blast loading represent an important topic in protective engineering. The assessment of blast survivability inside structures and the development of design provisions with respect to internal elements require the study of the propagation and leakage of blast waves inside buildings. In this paper, full-scale tests are performed to study the effects of the leakage of blast waves inside a partially vented room that is subjected to different external blast loadings. The results obtained may be useful for proving the validity of different methods of calculation, both empirical and numerical. Moreover, the experimental results are compared with those computed using the empirical curves of the US Defense report/manual UFC 3-340. Finally, results of the dynamic response of the front masonry wall are presented in terms of accelerations and an iso-damage diagram.
On the transmission of partial information: inferences from movement-related brain potentials
NASA Technical Reports Server (NTRS)
Osman, A.; Bashore, T. R.; Coles, M. G.; Donchin, E.; Meyer, D. E.
1992-01-01
Results are reported from a new paradigm that uses movement-related brain potentials to detect response preparation based on partial information. The paradigm uses a hybrid choice-reaction go/nogo procedure in which decisions about response hand and whether to respond are based on separate stimulus attributes. A lateral asymmetry in the movement-related brain potential was found on nogo trials without overt movement. The direction of this asymmetry depended primarily on the signaled response hand rather than on properties of the stimulus. When the asymmetry first appeared was influenced by the time required to select the signaled hand, and when it began to differ on go and nogo trials was influenced by the time to decide whether to respond. These findings indicate that both stimulus attributes were processed in parallel and that the asymmetry reflected preparation of the response hand that began before the go/nogo decision was completed.
Wave simulation in partially frozen porous media with fractal freezing conditions
NASA Astrophysics Data System (ADS)
Carcione, José M.; Santos, Juan E.; Ravazzoli, Claudia L.; Helle, Hans B.
2003-12-01
A recent article [J. M. Carcione and G. Seriani, J. Comput. Phys. 170, 676 (2001)] proposes a modeling algorithm for wave simulation in a three-phase porous medium composed of sand grains, ice, and water. The differential equations hold for uniform water (ice) content. Here, we obtain the variable-porosity differential equations by using the analogy with the two-phase case and the complementary energy theorem. The displacements of the rock and ice frames and the variation of fluid content are the generalized coordinates, and the stress components and fluid pressure are the generalized forces. We simulate wave propagation in a frozen porous medium with fractal variations of porosity and, therefore, realistic freezing conditions.
Analysis of Shear Wave Generation by Decoupled and Partially Coupled Explosions
2009-07-31
The explosive source is on scale relative to the cavity size. Two factors suggest that both explosions m ight act as spherical seism ic sources...REFERENCES Baker, G. E., H. Xu, and J. L. Stevens (2009), Generation of Shear Waves from Explosions in Water-Filled Cavities, submitted to Bull. Seism ...I: Seismic Spectrum Scaling, Bull. Seism . Soc. Am., 61, 1675-1692 Murphy, J. (1969), Discussion of Paper by D. Springer, M. Denny, J. Healy, and W
Potential future impact of a partially effective HIV vaccine in a southern African setting.
Phillips, Andrew N; Cambiano, Valentina; Nakagawa, Fumiyo; Ford, Deborah; Lundgren, Jens D; Roset-Bahmanyar, Edith; Roman, François; Van Effelterre, Thierry
2014-01-01
It is important for public health and within the HIV vaccine development field to understand the potential population level impact of an HIV vaccine of partial efficacy--both in preventing infection and in reducing viral load in vaccinated individuals who become infected--in the context of a realistic future implementation scenario in resource limited settings. An individual level model of HIV transmission, progression and the effect of antiretroviral therapy was used to predict the outcome to 2060 of introduction in 2025 of a partially effective vaccine with various combinations of efficacy characteristics, in the context of continued ART roll-out in southern Africa. In the context of our base case epidemic (in 2015 HIV prevalence 28% and incidence 1.7 per 100 person years), a vaccine with only 30% preventative efficacy could make a substantial difference in the rate with which HIV incidence declines; the impact on incidence in relative terms is projected to increase over time, with a projected 67% lower HIV incidence in 2060 compared with no vaccine introduction. The projected mean decline in the general adult population death rate 2040-2060 is 11%. A vaccine with no prevention efficacy but which reduces viral load by 1 log is predicted to result in a modest (14%) reduction in HIV incidence and an 8% reduction in death rate in the general adult population (mean 2040-2060). These effects were broadly similar in multivariable uncertainty analysis. Introduction of a partially effective preventive HIV vaccine would make a substantial long-term impact on HIV epidemics in southern Africa, in addition to the effects of ART. Development of an HIV vaccine, even of relatively low apparent efficacy at the individual level, remains a critical global public health goal.
Potential Geomorphic Consequences of Wave Climate Alterations along Cuspate Coastlines
NASA Astrophysics Data System (ADS)
Johnson, J.; Moore, L. J.; Ells, K. D.; Murray, A.
2012-12-01
While much attention has been given to the effects of sea level rise on coastal environments, changes in wave climate (in response to predicted increases in tropical storm intensity) may also significantly impact coastal areas in the future. Characterized by rapid alongshore shifts in shoreline orientation, cuspate coastlines are particularly sensitive to changes in wave climate and thus represent the best type of coastline for detecting initial responses to changing wave conditions. Previous work indicates that Cape Hatteras and Cape Lookout, NC have become increasingly asymmetric in response to an increase in Atlantic summer wave heights identified by Komar and Allen (2007). Here, we contrast historic and recent patterns of erosion and accretion for areas surrounding Cape Fear, NC and Fishing Point, VA to determine if a similar coastline response can be detected for a location heavily impacted by shoreline stabilization efforts and a location experiencing a less-pronounced trend of increasing wave energy, respectively. We obtained shorelines from NOAA, the USGS, and the North Carolina Department of Natural Resources and used the Digital Shoreline Analysis System (DSAS) to calculate shoreline change rates for historic (pre-1975) and recent (post-1975) time periods. The 1975 breakpoint was chosen to correspond with the timing of reported increases in hurricane-generated (summer) wave heights. Initial results suggest that the influence of shoreline stabilization efforts (primarily beach nourishment, one jetty and a few groins) has overwhelmed any wave-climate change response that may otherwise have been detectable surrounding Cape Fear, NC. Preliminary results for Fishing Point, VA indicate no discernible wave-climate related trend in shoreline change, suggesting that wave climate changes have not been of a significant magnitude to significantly influence patterns of erosion and accretion along this stretch of coastline. Coastline Evolution Model (CEM) simulations
Souza, Lívia Tereza Andrade; Oliveira, Jamil S.; dos Santos, Vera L.; Regis, Wiliam C. B.; Santoro, Marcelo M.; Resende, Rodrigo R.
2014-01-01
Lipolytic potential of Aspergillus japonicus LAB01 was investigated by describing the catalytic properties and stability of a secreted extracellular lipase. Enzyme production was considered high under room temperature after 4 days using sunflower oil and a combination of casein with sodium nitrate. Lipase was partially purified by 3.9-fold, resulting in a 44.2% yield using ammonium sulphate precipitation (60%) quantified with Superose 12 HR gel filtration chromatography. The activity of the enzyme was maximised at pH 8.5, and the enzyme demonstrated stability under alkaline conditions. The optimum temperature was found to be 45°C, and the enzyme was stable for up to 100 minutes, with more than 80% of initial activity remaining after incubation at this temperature. Partially purified enzyme showed reasonable stability with triton X-100 and was activated in the presence of organic solvents (toluene, hexane, and methanol). Among the tested ions, only Cu2+, Ni2+, and Al3+ showed inhibitory effects. Substrate specificity of the lipase was higher for C14 among various p-nitrophenyl esters assayed. The KM and V max values of the purified enzyme for p-nitrophenyl palmitate were 0.13 mM and 12.58 umol/(L·min), respectively. These features render a novel biocatalyst for industrial applications. PMID:25530954
Potential effects of translatory waves on estimation of peak flows
Hjalmarson, H.W.; Phillips, J.V.
1997-01-01
During the afternoon of August 19, 1971, an intense thunderstorm a few miles southwest of Wikieup, Arizona, produced one of the largest known flood peaks for a 49.2-square-km drainage basin. Initial computations of the peak discharge assumed stable flow conditions and a four-section slope area measurement indicated that discharge was 2,082 m3/s. Recent findings based on free-surface instability characteristics at the site suggest that gravitational forces exceeded boundary retarding forces, and flow in the wide sand channel was unstable. Computations for roll or translatory waves indicate that waves crashed into the highway bridge at velocities of as much as 12.5 m/s. The close agreement of free surface instability results, translatory wave computations, estimates of the steady flow on which the translatory waves traveled, and an eyewitness account of the translatory waves suggest the total peak discharge could have been 2,742 m3/s or 32% greater than the published discharge. The occurrence of translatory waves in natural channels may be more common than previously thought, and instability criteria should be considered for hydraulic analysis of flow in steep smooth channels.
Immunomodulatory potential of partially hydrolyzed β-lactoglobulin and large synthetic peptides.
Adel-Patient, Karine; Nutten, Sophie; Bernard, Hervé; Fritsché, Rodolphe; Ah-Leung, Sandrine; Meziti, Narimane; Prioult, Guénolée; Mercenier, Annick; Wal, Jean-Michel
2012-10-31
The immunomodulatory potential of fragments derived from the cow's milk allergen bovine β-lactoglobulin (BLG) was assessed in a mouse model of oral tolerance (OT) [Adel-Patient, K.; Wavrin, S.; Bernard, H.; Meziti, N.; Ah-Leung, S.; Wal, J. M. Oral tolerance and Treg cells are induced in BALB/c mice after gavage with bovine β-lactoglobulin. Allergy 2011, 66 (10), 1312-1321]. Native BLG (nBLG) and chemically denatured BLG (lacking S-S bridges, dBLG), products resulting from their hydrolysis using cyanogen bromide (CNBr) and some synthetic peptides, were produced and precisely characterized. CNBr hydrolysates correspond to pools of peptides of various sizes that are still associated by S-S bridges when derived from nBLG. nBLG, dBLG, and CNBr hydrolysate of nBLG efficiently prevented further sensitization. CNBr hydrolysate of dBLG was less efficient, suggesting that the association by S-S bridges of peptides increased their immunomodulatory potential. Conversely, synthetic peptides were inefficient even if covering 50% of the BLG sequence, demonstrating that the immunomodulatory potential requires the presence of all derived fragments of BLG and further supporting the use of partially hydrolyzed milk proteins to favor OT induction in infants with a risk of atopy.
The effect of coal bed dewatering and partial oxidation on biogenic methane potential
Jones, Elizabeth J.P.; Harris, Steve H.; Barnhart, Elliott P.; Orem, William H.; Clark, Arthur C.; Corum, Margo D.; Kirshtein, Julie D.; Varonka, Matthew S.; Voytek, Mary A.
2013-01-01
Coal formation dewatering at a site in the Powder River Basin was associated with enhanced potential for secondary biogenic methane determined by using a bioassay. We hypothesized that dewatering can stimulate microbial activity and increase the bioavailability of coal. We analyzed one dewatered and two water-saturated coals to examine possible ways in which dewatering influences coal bed natural gas biogenesis by looking at differences with respect to the native coal microbial community, coal-methane organic intermediates, and residual coal oxidation potential. Microbial biomass did not increase in response to dewatering. Small Subunit rRNA sequences retrieved from all coals sampled represented members from genera known to be aerobic, anaerobic and facultatively anaerobic. A Bray Curtis similarity analysis indicated that the microbial communities in water-saturated coals were more similar to each other than to the dewatered coal, suggesting an effect of dewatering. There was a higher incidence of long chain and volatile fatty acid intermediates in incubations of the dewatered coal compared to the water-saturated coals, and this could either be due to differences in microbial enzymatic activities or to chemical oxidation of the coal associated with O2 exposure. Dilute H2O2 treatment of two fractions of structural coal (kerogen and bitumen + kerogen) was used as a proxy for chemical oxidation by O2. The dewatered coal had a low residual oxidation potential compared to the water-saturated coals. Oxidation with 5% H2O2 did increase the bioavailability of structural coal, and the increase in residual oxidation potential in the water saturated coals was approximately equivalent to the higher methanogenic potential measured in the dewatered coal. Evidence from this study supports the idea that coal bed dewatering could stimulate biogenic methanogenesis through partial oxidation of the structural organics in coal once anaerobic conditions are restored.
NASA Astrophysics Data System (ADS)
Leonard, Stephen W.; Poisson, Eric
1998-08-01
The gravitational radiation originating from a compact binary system in circular orbit is usually expressed as an infinite sum over radiative multipole moments. In a slow-motion approximation, each multipole moment is expressed as a post-Newtonian expansion in powers of 0264-9381/15/8/002/img1, the ratio of the orbital velocity to the speed of light. The `bare multipole truncation' of the radiation consists in keeping only the leading-order (Newtonian) term in the post-Newtonian expansion of each moment, but summing over all the multipole moments. In the case of binary systems with small mass ratios, the bare multipole series was shown in a previous paper (Simone et al 1997 Class. Quantum Grav. 14 237) to converge for all values 0264-9381/15/8/002/img2, where e is the base of natural logarithms. (These include all physically relevant values for circular inspiral.) In this paper, we extend the analysis to a `partially bare multipole truncation' of the radiation, in which the leading-order moments are corrected with terms of relative order 0264-9381/15/8/002/img3 (first post-Newtonian, or 1PN, terms) and 0264-9381/15/8/002/img4 (1.5PN terms). We find that the partially bare multipole series also converges for all values 0264-9381/15/8/002/img2, and that it coincides (to within 1%) with the numerically `exact' results for 0264-9381/15/8/002/img6. Although this multipole series converges, it is an unphysical approximation, and the issue of the convergence of the true post-Newtonian series remains open. However, our analysis shows that an eventual failure of the true post-Newtonian series to converge cannot originate from summing over the Newtonian, 1PN and 1.5PN part of all the multipole moments.
NASA Astrophysics Data System (ADS)
Farsaei, Amir Ashkan; Mokhtari-Koushyar, Farzad; Javad Seyed-Talebi, Seyed Mohammad; Kavehvash, Zahra; Shabany, Mahdi
2016-03-01
Active millimeter-wave imaging based on synthetic aperture focusing offers certain unique and practical advantages in nondestructive testing applications. Traditionally, the imaging for this purpose is performed through a long procedure of raster scanning with a single antenna across a two-dimensional grid, leading to a slow, bulky, and expensive scanning platform. In this paper, an improved bistatic structure based on radial compressive sensing is proposed, where one fixed transmitter antenna and a linear array of receiving antennas are used. The main contributions of this paper are (a) reducing the scanning time, (b) improving the output quality, and (c) designing an inexpensive setup. These improvements are the result of the underlying proposed simpler scanning structure and faster reconstruction process.
NASA Astrophysics Data System (ADS)
Almqvist, B.; Misra, S.; Biedermann, A. R.; Mainprice, D.
2013-12-01
We studied the magnetic and elastic wave speed anisotropy of a synthetically prepared quartz-mica schist, prior to, during and after experimental melting. The synthetic rock was manufactured from a mixture of powders with equal volumes of quartz and muscovite. The powders were initially compacted with 200 MPa uniaxial stress at room temperature and sealed in a stainless steel canister. Subsequently the sealed canister was isostatically pressed at 180 MPa and 580 °C for 24 hours. This produced a solid medium with ~25 % porosity. Mica developed a preferred grain-shape alignment due to the initial compaction with differential load, where mica flakes tend to orient perpendicular to the applied stress and hence define a synthetic foliation plane. In the last stage we used a Paterson gas-medium apparatus, to pressurize and heat the specimens up to 300 MPa and 750 °C for a six hour duration. This stage initially compacted the rock, followed by generation of melt, and finally crystallization of new minerals from the melt. Elastic wave speed measurements were performed in situ at pressure and temperature, with a transducer assembly mounted next to the sample. Magnetic measurements were performed before and after the partial melt experiments. Anisotropy was measured in low- and high-field, using a susceptibility bridge and torsion magnetometer, respectively. Additionally we performed measurements of hysteresis, isothermal remanent magnetization (IRM) and susceptibility as a function of temperature, to investigate the magnetic properties of the rock. The elastic wave speed, before the melting-stage of the experiment, exhibits a distinct anisotropy with velocities parallel to the foliation being about 15 % higher than normal to the foliation plane. Measurements of the magnetic anisotropy in the bulk sample show that anisotropy is originating from the preferred orientation of muscovite, with a prominent flattening fabric. In contrast, specimens that underwent partial melting
The potential for very high-frequency gravitational wave detection
NASA Astrophysics Data System (ADS)
Cruise, A. M.
2012-05-01
The science case for observing gravitational waves at frequencies in the millihertz-kilohertz range using LIGO, VIRGO, GEO600 or LISA is very strong and the first results are expected at these frequencies. However, as gravitational wave astronomy progresses beyond the first detections, other frequency bands may be worth exploring. Early predictions of gravitational wave emission from discrete sources at very much higher frequencies (megahertz and above) have been published and more recent studies of cosmological signals from inflation, Kaluza-Klein modes from gravitational interactions in brane worlds and plasma instabilities surrounding violent astrophysical events, are all possible sources. This communication examines current observational possibilities and the detector technology required to make meaningful observations at these frequencies.
Hyde, Milo W; Basu, Santasri; Spencer, Mark F; Cusumano, Salvatore J; Fiorino, Steven T
2013-03-25
The scattering of a partially-coherent wave from a statistically rough material surface is investigated via derivation of the scattered field cross-spectral density function. Two forms of the cross-spectral density are derived using the physical optics approximation. The first is applicable to smooth-to-moderately rough surfaces and is a complicated expression of source and surface parameters. Physical insight is gleaned from its analytical form and presented in this work. The second form of the cross-spectral density function is applicable to very rough surfaces and is remarkably physical. Its form is discussed at length and closed-form expressions are derived for the angular spectral degree of coherence and spectral density radii. Furthermore, it is found that, under certain circumstances, the cross-spectral density function maintains a Gaussian Schell-model form. This is consistent with published results applicable only in the paraxial regime. Lastly, the closed-form cross-spectral density functions derived here are rigorously validated with scatterometer measurements and full-wave electromagnetic and physical optics simulations. Good agreement is noted between the analytical predictions and the measured and simulated results.
NASA Astrophysics Data System (ADS)
Cheviakov, Alexei F.; Bluman, George W.
2010-10-01
For many systems of partial differential equations (PDEs), including nonlinear ones, one can construct nonlocally related PDE systems. In recent years, such nonlocally related systems have proven to be useful in applications. In particular, they have yielded systematically nonlocal symmetries, nonlocal conservation laws, noninvertible linearizations, and new exact solutions for many different PDE systems of interest. However, the overwhelming majority of new results and theoretical understanding pertain only to PDE systems with two independent variables. The situation for PDE systems with more than two independent variables turns out to be much more complicated due to gauge freedom relating potential variables. The current paper, together with the companion paper [A. F. Cheviakov and G. W. Bluman, J. Math. Phys. 51, 103522 (2010)], synthesizes and systematically extends known results for nonlocally related systems arising for multidimensional PDE systems, i.e., for PDE systems with three or more independent variables. The presented framework includes potential systems arising from lower-degree conservation laws of a given PDE system. Nonlocally related multidimensional PDE systems are discussed in terms of their construction, properties, and applications.
Habituation and recovery of a slow negative wave of the event-related brain potential.
Zimmer, Heinz
2002-03-01
This study is concerned with the question of whether the late, slow negative wave 2 (SNW2) component of the event-related brain potential is a component of the orienting response (OR). As habituation of the SNW2 would be an argument for such a link with the OR, it was investigated using a variant of the classical repetition/change paradigm. Results supported major claims to be made for a component of the OR: the amplitude of the vertex SNW2 exhibited roughly the typical exponential decline with repeated stimulations (six numeric verbal stimuli presented seriatim in an ascending order) and responded incrementally to a change, at least in a narrow time slot, i.e. it exhibited partial recovery to an out-of-sequence stimulus. These findings were accompanied by similar effects on an exemplary OR component, the skin conductance response, and on such possible components of the OR as heart rate deceleration and the vertex P3 of the event-related brain potential. In so far as OR components should behave in comparable fashion in response to orienting stimuli, it is thus reasonable to suppose that the SNW2 relates to the OR.
NASA Astrophysics Data System (ADS)
Caldwell, Warren B.; Klemperer, Simon L.; Rai, Shyam S.; Lawrence, Jesse F.
2009-11-01
Seismic shear-wave velocities are sensitive to the partial melts that should be present in the Himalayan orogen if low-viscosity channel flow is active at the present day. We analyzed regional earthquakes in the western Himalaya and Tibet recorded on 16 broadband seismometers deployed across the NW Indian Himalaya, from the Indian platform to the Karakoram Range. We used a multiple filter technique to calculate the group velocity dispersion of fundamental-mode Rayleigh waves, and then inverted the dispersion records to obtain separate one-dimensional shear-wave velocity models for five geologic provinces: the Tibetan plateau, Ladakh arc complex, Indus Tsangpo suture zone, Tethyan Himalaya, and Himalayan thrust belt. Our velocity models show a low-velocity layer (LVL) with 7-17% velocity reduction centered at ~ 30 km depth and apparently continuous from the Tethyan Himalaya to the Tibetan plateau. This LVL shows good spatial correspondence with observations of low resistivity from magnetotelluric studies along the same profile. Of the possible explanations for low velocity and low resistivity in the mid-crust, only the presence of melts or aqueous fluids (or both) satisfactorily explains both sets of observations. Elevated heat flow observed in the NW Himalaya implies that if aqueous fluids are present in the mid-crust, then the mid-crust is well above its solidus. Comparison of our results with laboratory measurements and theoretical models suggests 3-7% melt is present in a channel in the upper-middle crust of the NW Himalaya at the present day, and the physical conditions to enable active channel flow may be present.
Quantization of wave equations and hermitian structures in partial differential varieties.
Paneitz, S M; Segal, I E
1980-12-01
Sufficiently close to 0, the solution variety of a nonlinear relativistic wave equation-e.g., of the form squarevarphi + m(2)varphi + gvarphi(p) = 0-admits a canonical Lorentz-invariant hermitian structure, uniquely determined by the consideration that the action of the differential scattering transformation in each tangent space be unitary. Similar results apply to linear time-dependent equations or to equations in a curved asymptotically flat space-time. A close relation of the Riemannian structure to the determination of vacuum expectation values is developed and illustrated by an explicit determination of a perturbative 2-point function for the case of interaction arising from curvature. The theory underlying these developments is in part a generalization of that of M. G. Krein and collaborators concerning stability of differential equations in Hilbert space and in part a precise relation between the unitarization of given symplectic linear actions and their full probabilistic quantization. The unique causal structure in the infinite symplectic group is instrumental in these developments.
Quantization of wave equations and hermitian structures in partial differential varieties
Paneitz, S. M.; Segal, I. E.
1980-01-01
Sufficiently close to 0, the solution variety of a nonlinear relativistic wave equation—e.g., of the form □ϕ + m2ϕ + gϕp = 0—admits a canonical Lorentz-invariant hermitian structure, uniquely determined by the consideration that the action of the differential scattering transformation in each tangent space be unitary. Similar results apply to linear time-dependent equations or to equations in a curved asymptotically flat space-time. A close relation of the Riemannian structure to the determination of vacuum expectation values is developed and illustrated by an explicit determination of a perturbative 2-point function for the case of interaction arising from curvature. The theory underlying these developments is in part a generalization of that of M. G. Krein and collaborators concerning stability of differential equations in Hilbert space and in part a precise relation between the unitarization of given symplectic linear actions and their full probabilistic quantization. The unique causal structure in the infinite symplectic group is instrumental in these developments. PMID:16592923
Off-shell Jost solutions for Coulomb and Coulomb-like interactions in all partial waves
Laha, U.; Bhoi, J.
2013-01-15
By exploiting the theory of ordinary differential equations, with judicious use of boundary conditions, interacting Green's functions and their integral transforms together with certain properties of higher transcendental functions, useful analytical expressions for the off-shell Jost solutions for motion in Coulomb and Coulomb-nuclear potentials are derived in maximal reduced form through different approaches to the problem in the representation space. The exact analytical expressions for the off-shell Jost solutions for Coulomb and Coulomb-like potentials are believed to be useful for the description of the charged particle scattering/reaction processes.
NASA Technical Reports Server (NTRS)
Bean, T. A.; Bowhill, S. A.
1973-01-01
Partial-reflection data collected for the eclipse of July 10, 1972 as well as for July 9 and 11, 1972, are analyzed to determine eclipse effects on D-region electron densities. The partial-reflection experiment was set up to collect data using an on-line PDP-15 computer and DECtape storage. The electron-density profiles show good agreement with results from other eclipses. The partial-reflection programs were changed after the eclipse data collection to improve the operation of the partial-reflection system. These changes were mainly due to expanded computer hardware and have simplified the operations of the system considerably.
Quantifying the potential of III-V/Si partial concentrator by a statistical approach
NASA Astrophysics Data System (ADS)
Lee, Kan-Hua; Araki, Kenji; Ota, Yasuyuki; Nishioka, Kensuke; Yamaguchi, Masafumi
2017-09-01
We propose a theoretical framework for analyzing the energy yields of partial concentrators. A partial concentrator uses a concentrator cell to absorb the principal defracted or reflected light rays from its concentrator optics and a backplane cell to absorbs the diffused or defocused light. This concept can be applied to the concentrator system when accurate sun-tracking is not available, such as on a vehicle. This analysis framework provides a simplified way to describe the uncertainties of solar incidences dealt by partial concentrator. This help identified a clearer design criteria of partial concentrator in order to outperform the flat-panel PV or conventional CPV.
Theory of action potential wave block at-a-distance in the heart
NASA Astrophysics Data System (ADS)
Otani, Niels F.
2007-02-01
Propagation failure of an action potential wave at a finite distance from its source (so-called type-II block) may cause spiral wave formation or wave breakup in the heart, phenomena that are believed to underlie lethal and nonlethal heart rhythm disorders. In this study, we develop a sufficient condition for this type of block in a homogeneous, spatially one-dimensional system. Using a topological argument, we find that type-II block of a wave will always occur when launched within a finite range of times if the velocity of the trailing edge of the preceding wave, as measured at the stimulus site, is smaller than the velocity of a wave launched with the minimum diastolic interval (DI) for which propagation is possible. This “blocking condition” is robust, remaining valid even when memory and waveback electrotonic effects are included. The condition suggests that type-II block is greatly facilitated when waves are initiated at irregular intervals in time such that (1) the velocities of consecutive waves are as different as possible and (2) the DIs preceding each wave fall on the steeply sloped portion of the action potential duration restitution curve as often as possible. The set of timing intervals between stimuli that are predicted by the blocking condition to produce block are found to be consistent with these guidelines, and also to agree well with a coupled-maps computer simulation model, for the case of waves launched by four rapidly and irregularly timed stimuli.
Electromagnetic waves in a model with Chern-Simons potential
NASA Astrophysics Data System (ADS)
Pis'mak, D. Yu.; Pis'mak, Yu. M.; Wegner, F. J.
2015-07-01
We investigated the appearance of Chern-Simons terms in electrodynamics at the surface or interface of materials. The requirement of locality, gauge invariance, and renormalizability in this model is imposed. Scattering and reflection of electromagnetic waves in three different homogeneous layers of media is determined. Snell's law is preserved. However, the transmission and reflection coefficient depend on the strength of the Chern-Simons interaction (connected with Hall conductance), and parallel and perpendicular components are mixed.
Sathaye, Jayant; Makundi, Willy; Dale, Larry; Chan, Peter; Andrasko, Kenneth
2005-03-22
This paper reports on the global potential for carbonsequestration in forest plantations, and the reduction of carbonemissions from deforestation, in response to six carbon price scenariosfrom 2000 to 2100. These carbon price scenarios cover a range typicallyseen in global integrated assessment models. The world forest sector wasdisaggregated into tenregions, four largely temperate, developedregions: the European Union, Oceania, Russia, and the United States; andsix developing, mostly tropical, regions: Africa, Central America, China,India, Rest of Asia, and South America. Three mitigation options -- long-and short-rotation forestry, and the reduction of deforestation -- wereanalyzed using a global dynamic partial equilibrium model (GCOMAP). Keyfindings of this work are that cumulative carbon gain ranges from 50.9 to113.2 Gt C by 2100, higher carbon prices early lead to earlier carbongain and vice versa, and avoided deforestation accounts for 51 to 78percent of modeled carbon gains by 2100. The estimated present value ofcumulative welfare change in the sector ranges from a decline of $158billion to a gain of $81 billion by 2100. The decline is associated witha decrease in deforestation.
Bhandari, Bharti; Subramanian, L
2007-01-01
Chronic Angina resistant to medical treatment with hemodynamically acting agents is a major problem in clinical setup. For such patients, large number of clinical trials have documented the beneficial effect of Ranolazine. It acts as an anti-anginal agent that controls myocardial ischemia through intracellular metabolic changes. Ranolazine is a partial fatty acid oxidation inhibitor which shifts cardiac energy metabolism from fatty acid oxidation to glucose oxidation. Since the oxidation of glucose requires less oxygen than the oxidation of fatty acids, ranolazine can help maintain myocardial function in times of ischemia. In addition, ranolazine has minimal effect on blood pressure and heart rate. Ranolazine, by inhibiting cellular ionic channels, prolongs the corrected QT interval. However, ranolazine has not yet been associated with any incidences of ventricular arrhythmia. Other possible mechanism by which Ranolazine could act is by reducing the formation of reactive oxygen species (ROS) and improves reperfusion mechanical function. Ranolazine has been approved by US FDA for the treatment of chronic angina pectoris in combination with amlodipine, beta-blockers or nitrates in patients who do not show adequate response to other anti-anginals. Ranolazine is a metabolic modulator that is being developed by CV Therapeutics (CVT), under license from Roche (formerly Syntex), as a potential treatment for angina. Ranolazine is available as brand name 'Ranexa' as extended release oral tablets. This review focuses on the clinical effects, the mechanism of actions, drug interactions and beneficial effects of Ranolazine in chronic angina and other cardiometabolic disorders.
Dodd, Ian C; Egea, Gregorio; Watts, Chris W; Whalley, W Richard
2010-08-01
To investigate the influence of different growing substrates (two mineral, two organic) on root xylem ABA concentration ([ABA](root)) and the contribution of the drying root system to total sap flow during partial rootzone drying (PRD), sunflower (Helianthus annuus L.) shoots were grafted onto the root systems of two plants grown in separate pots. Sap flow through each hypocotyl was measured below the graft union when one pot ('wet') was watered and other ('dry') was not. Each substrate gave unique relationships between dry pot matric potential (Psi(soil)), volumetric water content ((v)) or penetrometer resistance (Q) and either the fraction of photoperiod sap flow from roots in drying soil or [ABA](root). However, decreased relative sap flow, and increased [ABA](root), from roots in drying soil varied with root water potential (Psi(root)) more similarly across a range of substrates. The gradient between Psi(soil) and Psi(root) was greater in substrates with high sand or peat proportions, which may have contributed to a more sensitive response of [ABA](root) to Psi(soil) in these substrates. Whole plant transpiration was most closely correlated with the mean Psi(soil) of both pots, and then with detached leaf xylem ABA concentration. Although Psi(root) best predicted decreased relative sap flow, and increased [ABA](root), from roots in drying soil across a range of substrates, the inaccessibility of this variable in field studies requires a better understanding of how measurable soil variables (Psi(soil), (v), Q) affect Psi(root).
Lovelock, Paul K; Spurdle, Amanda B; Mok, Myth TS; Farrugia, Daniel J; Lakhani, Sunil R; Healey, Sue; Arnold, Stephen; Buchanan, Daniel; Investigators, kConFab; Couch, Fergus J; Henderson, Beric R; Goldgar, David E; Tavtigian, Sean V; Chenevix-Trench, Georgia; Brown, Melissa A
2007-01-01
Introduction Many of the DNA sequence variants identified in the breast cancer susceptibility gene BRCA1 remain unclassified in terms of their potential pathogenicity. Both multifactorial likelihood analysis and functional approaches have been proposed as a means to elucidate likely clinical significance of such variants, but analysis of the comparative value of these methods for classifying all sequence variants has been limited. Methods We have compared the results from multifactorial likelihood analysis with those from several functional analyses for the four BRCA1 sequence variants A1708E, G1738R, R1699Q, and A1708V. Results Our results show that multifactorial likelihood analysis, which incorporates sequence conservation, co-inheritance, segregation, and tumour immunohistochemical analysis, may improve classification of variants. For A1708E, previously shown to be functionally compromised, analysis of oestrogen receptor, cytokeratin 5/6, and cytokeratin 14 tumour expression data significantly strengthened the prediction of pathogenicity, giving a posterior probability of pathogenicity of 99%. For G1738R, shown to be functionally defective in this study, immunohistochemistry analysis confirmed previous findings of inconsistent 'BRCA1-like' phenotypes for the two tumours studied, and the posterior probability for this variant was 96%. The posterior probabilities of R1699Q and A1708V were 54% and 69%, respectively, only moderately suggestive of increased risk. Interestingly, results from functional analyses suggest that both of these variants have only partial functional activity. R1699Q was defective in foci formation in response to DNA damage and displayed intermediate transcriptional transactivation activity but showed no evidence for centrosome amplification. In contrast, A1708V displayed an intermediate transcriptional transactivation activity and a normal foci formation response in response to DNA damage but induced centrosome amplification. Conclusion
Surface-wave potential for triggering tectonic (nonvolcanic) tremor-corrected
Hill, David P.
2012-01-01
Source processes commonly posed to explain instances of remote dynamic triggering of tectonic (nonvolcanic) tremor by surface waves include frictional failure and various modes of fluid activation. The relative potential for Love- and Rayleigh-wave dynamic stresses to trigger tectonic tremor through failure on critically stressed thrust and vertical strike-slip faults under the Coulomb-Griffith failure criteria as a function of incidence angle are anticorrelated over the 15- to 30-km-depth range that hosts tectonic tremor. Love-wave potential is high for strike-parallel incidence on low-angle reverse faults and null for strike-normal incidence; the opposite holds for Rayleigh waves. Love-wave potential is high for both strike-parallel and strike-normal incidence on vertical, strike-slip faults and minimal for ~45° incidence angles. The opposite holds for Rayleigh waves. This pattern is consistent with documented instances of tremor triggered by Love waves incident on the Cascadia megathrust and the San Andreas fault (SAF) in central California resulting from shear failure on weak faults (apparent friction is μ* ≤ 0:2). Documented instances of tremor triggered by surface waves with strike-parallel incidence along the Nankai megathrust beneath Shikoku, Japan, however, are associated primarily with Rayleigh waves. This is consistent with the tremor bursts resulting from mixed-mode failure (crack opening and shear failure) facilitated by near-lithostatic ambient pore pressure, low differential stress, with a moderate friction coefficient (μ ~ 0:6) on the Nankai subduction interface. Rayleigh-wave dilatational stress is relatively weak at tectonic tremor source depths and seems unlikely to contribute significantly to the triggering process, except perhaps for an indirect role on the SAF in sustaining tremor into the Rayleigh-wave coda that was initially triggered by Love waves.
Das, J.N.; Paul, S.; Chakrabarti, K.
2004-04-01
Here we report a set of converged cross-section results for double photoionization of helium atoms obtained in the hyperspherical partial wave theory for equal energy sharing kinematics at 6 eV energy above threshold. The calculated cross section results are generally in excellent agreement with the absolute measured results of Doerner et al. [Phys. Rev. 57, 1074 (1998)].
NASA Astrophysics Data System (ADS)
Hetmaniuk, Ulrich Ladislas
Fast solvers are often designed for problems posed on simple domains. Unfortunately, engineering applications deal with arbitrary domains. To allow the use of fast solvers, fictitious domain methods have been developed. They usually define an auxiliary problem on a rectangle or a parallelepiped. In aerospace and military applications, many scatterers are composed of one major axisymmetric component and a few features. Therefore, the aim of this thesis is to define, for the scattering of acoustic waves, fictitious domain methods which exploit such local axisymmetry. The original exterior problem is first approximated by introducing an absorbing boundary condition on an artificial boundary. A family of absorbing conditions is reviewed. For some simple scatterers, numerical experiments on the position of the artificial boundary reveal that the error induced by the absorbing condition is bounded, as the wave number increases, when the artificial boundary is fixed. Then, for a class of partially axisymmetric scatterers, the truncated computational domain is embedded into an axisymmetric domain. Helmholtz problems are formulated inside this axisymmetric domain and inside each feature. Lagrange multipliers are introduced at the interfaces between the features and the axisymmetric domain to enforce a set of carefully constructed constraints. This formulation is analyzed at the continuous level and is shown to be equivalent to the original one. For the Helmholtz equation defined over the axisymmetric domain, the solution is approximated by truncated Fourier series and finite elements. Properties of this discretization method for the Helmholtz equation are also analyzed on a two-dimensional model problem. Numerical experiments are performed to illustrate the analytical results. For the auxiliary problem inside each feature, classical finite elements are used to approximate the solution. The constraints are enforced pointwise. The resulting algebraic system is solved either
Thermoacoustical wave generation and propagation in the cornea: the potential for damage
NASA Astrophysics Data System (ADS)
Benson, Alvin K.; Bargeron, C. Brent; Brady, Samuel L.; Denning, Adam W.; Page, Leland M.; McCally, Russell L.
2007-02-01
Carbon dioxide lasers are used in numerous applications that involve human exposure to the radiation that can produce ocular injury. The objective of this study is to show that the thermal gradient produced in the eye by the radiation from an 80 ns CO II laser pulse can generate a thermoacoustical tensile pressure wave with large enough magnitude to rupture the epithelial layer of the cornea. A Gaussian-shaped temperature distribution will be employed. It is assumed that the corneal tissue is inhomogeneous, with the density and wave velocity varying slowly in space. Under these conditions, the acoustical wave equation is decoupled into two first-order partial differential equations, one that propagates energy into the eye from the point of thermoacoustical wave generation, and the other toward the front of the eye. These equations are solved numerically using the Lax-Wendroff numerical method. A compressional wave generated in the epithelial tissue of the cornea due to the thermal gradient of the laser arrives at the air-tear layer interface with a pressure amplitude of ~6600 Pa. When this wave is reflected back into the eye, the resulting tensile pressure wave has a tensile strength of approximately 4.6 x 10 8 Pa/m just inside of the epithelial layer of the cornea. This is an order of magnitude larger than what is necessary to produce cellular damage to the cornea.
NASA Astrophysics Data System (ADS)
Claisse, J.; Pondella, D.; Love, M.; Zahn, L.; Williams, C.; Bull, A. S.
2016-02-01
When oil and gas platforms become obsolete they go through a decommissioning process. This may include partial removal (from the surface to 26 m depth) or complete removal of the platform structure. While complete removal would likely eliminate most of the existing fish biomass and associated secondary production, we find that the potential impacts of partial removal would likely be limited on all but one platform off the coast of California. On average 80% of fish biomass and 86% of secondary fish production would be retained after partial removal, with above 90% retention expected for both metrics on many platforms. Partial removal would likely result in the loss of fish biomass and production for species typically found residing in the shallow portions of the platform structure. However, these fishes generally represent a small proportion of the fishes associated with these platforms. More characteristic of platform fauna are the primarily deeper-dwelling rockfishes (genus Sebastes). "Shell mounds" are biogenic reefs that surround some of these platforms resulting from an accumulation of mollusk shells that have fallen from the shallow areas of the platforms mostly above the depth of partial removal. We found that shell mounds are moderately productive fish habitats, similar to or greater than natural rocky reefs in the region at comparable depths. The complexity and areal extent of these biogenic habitats, and the associated fish biomass and production, will likely be reduced after either partial or complete platform removal. Habitat augmentation by placing the partially removed platform superstructure or some other additional habitat enrichment material (e.g., rock boulders) on the seafloor adjacent to the base of partially removed platforms provides additional options to enhance fish production, potentially mitigating reductions in shell mound habitat.
Continuity Conditions on Schrodinger Wave Functions at Discontinuities of the Potential.
ERIC Educational Resources Information Center
Branson, David
1979-01-01
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)
Continuity Conditions on Schrodinger Wave Functions at Discontinuities of the Potential.
ERIC Educational Resources Information Center
Branson, David
1979-01-01
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)
Potential applications of low-energy shock waves in functional urology.
Wang, Hung-Jen; Cheng, Jai-Hong; Chuang, Yao-Chi
2017-08-01
A shock wave, which carries energy and can propagate through a medium, is a type of continuous transmitted sonic wave with a frequency of 16 Hz-20 MHz. It is accompanied by processes involving rapid energy transformations. The energy associated with shock waves has been harnessed and used for various applications in medical science. High-energy extracorporeal shock wave therapy is the most successful application of shock waves, and has been used to disintegrate urolithiasis for 30 years. At lower energy levels, however, shock waves have enhanced expression of vascular endothelial growth factor, endothelial nitric oxide synthase, proliferating cell nuclear antigen, chemoattractant factors and recruitment of progenitor cells; shock waves have also improved tissue regeneration. Low-energy shock wave therapy has been used clinically with musculoskeletal disorders, ischemic cardiovascular disorders and erectile dysfunction, through the mechanisms of neovascularization, anti-inflammation and tissue regeneration. Furthermore, low-energy shock waves have been proposed to temporarily increase tissue permeability and facilitate intravesical drug delivery. The present review article provides information on the basics of shock wave physics, mechanisms of action on the biological system and potential applications in functional urology. © 2017 The Japanese Urological Association.
Loftis, Jennifer M.; Wilhelm, Clare J.; Vandenbark, Arthur A.; Huckans, Marilyn
2013-01-01
Relapse rates following current methamphetamine abuse treatments are very high (∼40–60%), and the neuropsychiatric impairments (e.g., cognitive deficits, mood disorders) that arise and persist during remission from methamphetamine addiction likely contribute to these high relapse rates. Pharmacotherapeutic development of medications to treat addiction has focused on neurotransmitter systems with only limited success, and there are no Food and Drug Administration approved pharmacotherapies for methamphetamine addiction. A growing literature shows that methamphetamine alters peripheral and central immune functions and that immune factors such as cytokines, chemokines, and adhesion molecules play a role in the development and persistence of methamphetamine induced neuronal injury and neuropsychiatric impairments. The objective of this study was to evaluate the efficacy of a new immunotherapy, partial MHC/neuroantigen peptide construct (RTL551; pI-Ab/mMOG-35-55), in treating learning and memory impairments induced by repeated methamphetamine exposure. C57BL/6J mice were exposed to two different methamphetamine treatment regimens (using repeated doses of 4 mg/kg or 10 mg/kg, s.c.). Cognitive performance was assessed using the Morris water maze and CNS cytokine levels were measured by multiplex assay. Immunotherapy with RTL551 improved the memory impairments induced by repeated methamphetamine exposure in both mouse models of chronic methamphetamine addiction. Treatment with RTL551 also attenuated the methamphetamine induced increases in hypothalamic interleukin-2 (IL-2) levels. Collectively, these initial results indicate that neuroimmune targeted therapies, and specifically RTL551, may have potential as treatments for methamphetamine-induced neuropsychiatric impairments. PMID:23460798
Single-Trial Visual Evoked Potential Extraction Using Partial Least-Squares-Based Approach.
Kristina Yanti, Duma; Zuki Yusoff, Mohd; Sagayan Asirvadam, Vijanth
2016-01-01
A single-trial extraction of a visual evoked potential (VEP) signal based on the partial least-squares (PLS) regression method has been proposed in this paper. This paper has focused on the extraction and estimation of the latencies of P100, P200, P300, N75, and N135 in the artificial electroencephalograph (EEG) signal. The real EEG signal obtained from the hospital was only concentrated on the P100. The performance of the PLS has been evaluated mainly on the basis of latency error rate of the peaks for the artificial EEG signal, and the mean peak detection and standard deviation for the real EEG signal. The simulation results show that the proposed PLS algorithm is capable of reconstructing the EEG signal into its desired shape of the ideal VEP. For P100, the proposed PLS algorithm is able to provide comparable results to the generalized eigenvalue decomposition (GEVD) algorithm, which alters (prewhitens) the EEG input signal using the prestimulation EEG signal. It has also shown better performance for later peaks (P200 and P300). The PLS outperformed not only in positive peaks but also in N75. In P100, the PLS was comparable with the GEVD although N135 was better estimated by GEVD. The proposed PLS algorithm is comparable to GEVD given that PLS does not alter the EEG input signal. The PLS algorithm gives the best estimate to multitrial ensemble averaging. This research offers benefits such as avoiding patient's fatigue during VEP test measurement in the hospital, in BCI applications and in EEG-fMRI integration.
Loftis, Jennifer M; Wilhelm, Clare J; Vandenbark, Arthur A; Huckans, Marilyn
2013-01-01
Relapse rates following current methamphetamine abuse treatments are very high (∼40-60%), and the neuropsychiatric impairments (e.g., cognitive deficits, mood disorders) that arise and persist during remission from methamphetamine addiction likely contribute to these high relapse rates. Pharmacotherapeutic development of medications to treat addiction has focused on neurotransmitter systems with only limited success, and there are no Food and Drug Administration approved pharmacotherapies for methamphetamine addiction. A growing literature shows that methamphetamine alters peripheral and central immune functions and that immune factors such as cytokines, chemokines, and adhesion molecules play a role in the development and persistence of methamphetamine induced neuronal injury and neuropsychiatric impairments. The objective of this study was to evaluate the efficacy of a new immunotherapy, partial MHC/neuroantigen peptide construct (RTL551; pI-A(b)/mMOG-35-55), in treating learning and memory impairments induced by repeated methamphetamine exposure. C57BL/6J mice were exposed to two different methamphetamine treatment regimens (using repeated doses of 4 mg/kg or 10 mg/kg, s.c.). Cognitive performance was assessed using the Morris water maze and CNS cytokine levels were measured by multiplex assay. Immunotherapy with RTL551 improved the memory impairments induced by repeated methamphetamine exposure in both mouse models of chronic methamphetamine addiction. Treatment with RTL551 also attenuated the methamphetamine induced increases in hypothalamic interleukin-2 (IL-2) levels. Collectively, these initial results indicate that neuroimmune targeted therapies, and specifically RTL551, may have potential as treatments for methamphetamine-induced neuropsychiatric impairments.
Partial wave analysis of the reaction {gamma}p{yields}p{omega} and the search for nucleon resonances
Williams, M.; Applegate, D.; Bellis, M.; Meyer, C. A.; Dey, B; Dickson, R.; Krahn, Z.; McCracken, M. E.; Moriya, K.; Schumacher, R. A.; Adhikari, K. P.; Careccia, S. L.; Dodge, G. E.; Guler, N.; Klein, A.; Mayer, M.; Nepali, C. S.; Niroula, M. R.; Seraydaryan, H.; Tkachenko, S.
2009-12-15
An event-based partial wave analysis (PWA) of the reaction {gamma}p{yields}p{omega} has been performed on a high-statistics dataset obtained using the CLAS at Jefferson Lab for center-of-mass energies from threshold up to 2.4 GeV. This analysis benefits from access to the world's first high-precision spin-density matrix element measurements, available to the event-based PWA through the decay distribution of {omega}{yields}{pi}{sup +}{pi}{sup -}{pi}{sup 0}. The data confirm the dominance of the t-channel {pi}{sup 0} exchange amplitude in the forward direction. The dominant resonance contributions are consistent with the previously identified states F{sub 15}(1680) and D{sub 13}(1700) near threshold, as well as the G{sub 17}(2190) at higher energies. Suggestive evidence for the presence of a J{sup P}=5/2{sup +} state around 2 GeV, a ''missing'' state, has also been found. Evidence for other states is inconclusive.
NASA Astrophysics Data System (ADS)
Benedito, E.; Fernández-Varea, J. M.; Salvat, F.
2001-03-01
We describe an algorithm for mixed (class II) simulation of electron multiple elastic scattering using numerical differential cross-sections (DCS), which is applicable in a wide energy range, from ˜100 eV to ˜1 GeV. DCSs are calculated by partial-wave analysis, or from a suitable high-energy approximation, and tabulated on a grid of scattering angles and electron energies. The size of the required DCS table is substantially reduced by means of a change of variable that absorbs most of the energy dependence of the DCS. That is, the scattering angle θ is replaced by a variable u, whose probability distribution function varies smoothly with the kinetic energy of the electron. A fast procedure to generate random values of u in restricted intervals is described. The algorithm for the simulation of electron transport in pure elastic scattering media (with energy-loss processes switched off) is obtained by combining this sampling procedure with a simple model for space displacements. The accuracy and stability of this algorithm is demonstrated by comparing results with those from detailed, event by event, simulations using the same DCSs. A complete transport code, including energy losses and the production of secondary radiations, is obtained by coupling the present elastic scattering simulation algorithm to the general-purpose Monte Carlo program PENELOPE. Simulated angular distributions of MeV electrons backscattered in aluminium and gold are in good agreement with experimental data.
NASA Astrophysics Data System (ADS)
Tokgöz, Çaǧatay; Dardona, Sameh
2016-09-01
Electrical failures in avionics systems may result from connector faults. If fault precursors are not detected in advance, they may lead to hard failures such as open and short circuits that could ultimately result in fire or loss of flight critical systems. Therefore, It is crucial to detect, locate, and characterize fault precursors for timely preventive maintenance and mitigation before hard failures occur. In this paper, a physics-based connector model consisting of multiple coaxial line sections with different characteristic impedances and lengths is proposed. Method of Moments (MoM) analyses were performed using commercial electromagnetic simulation software, FEKO, for transverse electric and magnetic (TEM) wave propagation through a connector. The physical parameters of the connector were optimized to match the measured S parameters for multiple insertion depths. The proposed models represent the connector for multiple insertion depths by varying only two length parameters at a time while other parameters are fixed. Insertion depth-dependent resonant frequency shifts observed during measurement are also captured by the model over the full range of fully inserted to barely touching contacts. Hence, the models provide accurate representations of the connector and properly detect precursors to partial insertion faults.
Partial wave analysis of the reaction γp→pω and the search for nucleon resonances
Williams, M.; Applegate, D.; Bellis, M.; ...
2009-12-30
We performed an event-based partial wave analysis (PWA) of the reaction γ p -> p ω on a high-statistics dataset obtained using the CLAS at Jefferson Lab for center-of-mass energies from threshold up to 2.4 GeV. This analysis benefits from access to the world's first high precision spin density matrix element measurements, available to the event-based PWA through the decay distribution of omega-> π+ π - π0. The data confirm the dominance of the t-channel π0 exchange amplitude in the forward direction. The dominant resonance contributions are consistent with the previously identified states F[15](1680) and D[13](1700) near threshold, as wellmore » as the G[17](2190) at higher energies. Suggestive evidence for the presence of a J(P)=5/2+ state around 2 GeV, a "missing" state, has also been found. Evidence for other states is inconclusive.« less
NASA Astrophysics Data System (ADS)
Zodiatis, George; Galanis, George; Nikolaidis, Andreas; Stylianoy, Stavros; Liakatas, Aristotelis
2015-04-01
The use of wave energy as an alternative renewable is receiving attention the last years under the shadow of the economic crisis in Europe and in the light of the promising corresponding potential especially for countries with extended coastline. Monitoring and studying the corresponding resources is further supported by a number of critical advantages of wave energy compared to other renewable forms, like the reduced variability and the easier adaptation to the general grid, especially when is jointly approached with wind power. Within the framework, a number of countries worldwide have launched research and development projects and a significant number of corresponding studies have been presented the last decades. However, in most of them the impact of wave-sea surface currents interaction on the wave energy potential has not been taken into account neglecting in this way a factor of potential importance. The present work aims at filling this gap for a sea area with increased scientific and economic interest, the Eastern Mediterranean Sea. Based on a combination of high resolution numerical modeling approach with advanced statistical tools, a detailed analysis is proposed for the quantification of the impact of sea surface currents, which produced from downscaling the MyOcean-FO regional data, to wave energy potential. The results although spatially sensitive, as expected, prove beyond any doubt that the wave- sea surface currents interaction should be taken into account for similar resource analysis and site selection approaches since the percentage of impact to the available wave power may reach or even exceed 20% at selected areas.
Tandem shock waves in medicine and biology: a review of potential applications and successes
NASA Astrophysics Data System (ADS)
Lukes, P.; Fernández, F.; Gutiérrez-Aceves, J.; Fernández, E.; Alvarez, U. M.; Sunka, P.; Loske, A. M.
2016-01-01
Shock waves have been established as a safe and effective treatment for a wide range of diseases. Research groups worldwide are working on improving shock wave technology and developing new applications of shock waves to medicine and biology. The passage of a shock wave through soft tissue, fluids, and suspensions containing cells may result in acoustic cavitation i.e., the expansion and violent collapse of microbubbles, which generates secondary shock waves and the emission of microjets of fluid. Cavitation has been recognized as a significant phenomenon that produces both desirable and undesirable biomedical effects. Several studies have shown that cavitation can be controlled by emitting two shock waves that can be delayed by tenths or hundreds of microseconds. These dual-pulse pressure pulses, which are known as tandem shock waves, have been shown to enhance in vitro and in vivo urinary stone fragmentation, cause significant cytotoxic effects in tumor cells, delay tumor growth, enhance the bactericidal effect of shock waves and significantly increase the efficiency of genetic transformations in bacteria and fungi. This article provides an overview of the basic physical principles, methodologies, achievements and potential uses of tandem shock waves to improve biomedical applications.
Potential hydrogen and oxygen partial pressures in legacy plutonium oxide packages at Oak Ridge
Veirs, Douglas K.
2014-07-07
An approach to estimate the maximum hydrogen and oxygen partial pressures within sealed containers is described and applied to a set of packages containing high-purity plutonium dioxide. The approach uses experimentally determined maximum hydrogen and oxygen partial pressures and scales the experimentally determined pressures to the relevant packaged material properties. The important material properties are the specific wattage and specific surface area (SSA). Important results from the experimental determination of maximum partial pressures are (1) the ratio of hydrogen to oxygen is stoichiometric, and (2) the maximum pressures increase with increasing initial rates of production. The material properties that influence the rates are the material specific wattage and the SSA. The unusual properties of these materials, high specific wattage and high SSA, result in higher predicted maximum pressures than typical plutonium dioxide in storage. The pressures are well within the deflagration range for mixtures of hydrogen and oxygen.
An Overview of the Cyclic Partial Austenite-Ferrite Transformation Concept and Its Potential
NASA Astrophysics Data System (ADS)
Chen, Hao; van der Zwaag, Sybrand
2017-06-01
Over the past decades, the mechanism of interface migration during the austenite-ferrite transformation in steels has attracted significant attention from physical metallurgists. There are two challenging research questions in this field: (i) What is the effect of (substitutional) alloying elements on migrating interfaces? and (ii) How to accurately determine the value of interface mobility?. Recently, a cyclic partial phase transformation approach has been proposed to study interface migration, and new insights into the above two questions have been provided. An overview of the cyclic partial phase transformation concept is given, and pathways for future research are suggested.
NASA Astrophysics Data System (ADS)
Boshier, Malcolm; Ryu, Changhyun; Blackburn, Paul; Blinova, Alina; Henderson, Kevin
2014-05-01
The painted potential is a time-averaged optical dipole potential which is able to create arbitrary and dynamic two dimensional potentials for Bose Einstein condensates (BECs). This poster reports three recent experiments using this technique. First, we have realized the dc atom SQUID geometry of a BEC in a toroidal trap with two Josephson junctions. We observe Josephson effects, measure the critical current of the junctions, and find dynamic behavior that is in good agreement with the simple Josephson equations for a tunnel junction with the ideal sinusoidal current-phase relation expected for the parameters of the experiment. Second, we have used free expansion of a rotating toroidal BEC to create matter wave Bessel beams, which are of interest because perfect Bessel beams (plane waves with amplitude profiles described by Bessel functions) propagate without diffraction. Third, we have realized the basic circuit elements necessary to create complex matter wave circuits. We launch BECs at arbitrary velocity along straight waveguides, propagate them around curved waveguides and stadium-shaped waveguide traps, and split them coherently at y-junctions that can also act as switches. Supported by LANL/LDRD.
A catalogue of potentially bright close binary gravitational wave sources
NASA Technical Reports Server (NTRS)
Webbink, Ronald F.
1985-01-01
This is a current print-out of results of a survey, undertaken in the spring of 1985, to identify those known binary stars which might produce significant gravitational wave amplitudes at earth, either dimensionless strain amplitudes exceeding a threshold h = 10(exp -21), or energy fluxes exceeding F = 10(exp -12) erg cm(exp -2) s(exp -1). All real or putative binaries brighter than a certain limiting magnitude (calculated as a function of primary spectral type, orbital period, orbital eccentricity, and bandpass) are included. All double degenerate binaries and Wolf-Rayet binaries with known or suspected orbital periods have also been included. The catalog consists of two parts: a listing of objects in ascending order of Right Ascension (Equinox B1950), followed by an index, listing of objects by identification number according to all major stellar catalogs. The object listing is a print-out of the spreadsheets on which the catalog is currently maintained. It should be noted that the use of this spreadsheet program imposes some limitations on the display of entries. Text entries which exceed the cell size may appear in truncated form, or may run into adjacent columns. Greek characters are not available; they are represented here by the first two or three letters of their Roman names, the first letter appearing as a capital or lower-case letter according to whether the capital or lower-case Greek character is represented. Neither superscripts nor subscripts are available; they appear here in normal position and type-face. The index provides the Right Ascension and Declination of objects sorted by catalogue number.
A catalogue of potentially bright close binary gravitational wave sources
NASA Astrophysics Data System (ADS)
Webbink, Ronald F.
This is a current print-out of results of a survey, undertaken in the spring of 1985, to identify those known binary stars which might produce significant gravitational wave amplitudes at earth, either dimensionless strain amplitudes exceeding a threshold h = 10-21, or energy fluxes exceeding F = 10-12 erg cm-2 s-1. All real or putative binaries brighter than a certain limiting magnitude (calculated as a function of primary spectral type, orbital period, orbital eccentricity, and bandpass) are included. All double degenerate binaries and Wolf-Rayet binaries with known or suspected orbital periods have also been included. The catalog consists of two parts: a listing of objects in ascending order of Right Ascension (Equinox B1950), followed by an index, listing of objects by identification number according to all major stellar catalogs. The object listing is a print-out of the spreadsheets on which the catalog is currently maintained. It should be noted that the use of this spreadsheet program imposes some limitations on the display of entries. Text entries which exceed the cell size may appear in truncated form, or may run into adjacent columns. Greek characters are not available; they are represented here by the first two or three letters of their Roman names, the first letter appearing as a capital or lower-case letter according to whether the capital or lower-case Greek character is represented. Neither superscripts nor subscripts are available; they appear here in normal position and type-face. The index provides the Right Ascension and Declination of objects sorted by catalogue number.
Acoustic Solitary Waves and Sagdeev Potential Triple Roots
Hellberg, M. A.; Baluku, T. K.; Verheest, F.
2010-12-14
Both KdV theory and the standard pseudopotential theory require that solitons and double layers be explicitly super-acoustic, with the pseudopotential {psi}({phi},M) having a maximum at the origin. Recent studies of a variety of different three-component plasmas have shown that they may support finite amplitude solitons at the true acoustic speed of the plasma configuration, M{sub s}. These are associated with triple roots of the Sagdeev potential, and the usual soliton condition is replaced by {psi}''(0,M){<=}0. Sagdeev potentials for speeds marginally greater than M{sub s} then represent solitons of both polarities, one whose amplitude vanishes at M{sub s}(KdV-like), while the other is necessarily finite at M{sub s}('nonKdV-like'). Such coexistence regions have been observed to be linked to a critical plasma compositional parameter value for which {psi}'''(0,M{sub s}) = 0.
Phase-matched four wave mixing and quantum beam splitting of matter waves in a periodic potential
Hilligsoee, Karen Marie; Moelmer, Klaus
2005-04-01
We show that the dispersion properties imposed by an external periodic potential ensure both energy and quasimomentum conservation such that correlated pairs of atoms can be generated by four wave mixing from a Bose-Einstein condensate moving in an optical lattice potential. In our numerical solution of the Gross-Pitaevskii equation, a condensate with initial quasimomentum k{sub 0} is transferred almost completely (>95%) into a pair of correlated atomic components with quasimomenta k{sub 1} and k{sub 2}, if the system is seeded with a smaller number of atoms with the appropriate quasimomentum k{sub 1}.
Bifurcation of space-charge wave in a plasma waveguide including the wake potential effect
Lee, Myoung-Jae; Jung, Young-Dae
2016-09-15
The wake potential effects on the propagation of the space-charge dust ion-acoustic wave are investigated in a cylindrically bounded dusty plasma with the ion flow. The results show that the wake potential would generate the double frequency modes in a cylindrically bounded dusty plasma. It is found that the upper mode of the wave frequency with the root of higher-order is smaller than that with the root of lower-order in intermediate wave number domains. However, the lower mode of the scaled wave frequency with the root of higher-order is found to be greater than that with the root of lower-order. It is found that the influence in the order of the root of the Bessel function on the wave frequency of the space-charge dust-ion-acoustic wave in a cylindrically confined dusty plasma decreases with an increase in the propagation wave number. It is also found that the double frequency modes increase with increasing Mach number due to the ion flow in a cylindrical dusty plasma. In addition, it is found that the upper mode of the group velocity decreases with an increase in the scaled radius of the plasma cylinder. However, it is shown that the lower mode of the scaled group velocity of the space-charge dust ion acoustic wave increases with an increase in the radius of the plasma cylinder. The variation of the space-charge dust-ion-acoustic wave due to the wake potential and geometric effects is also discussed.
The impact of sea surface currents in wave power potential modeling
NASA Astrophysics Data System (ADS)
Zodiatis, George; Galanis, George; Kallos, George; Nikolaidis, Andreas; Kalogeri, Christina; Liakatas, Aristotelis; Stylianou, Stavros
2015-11-01
The impact of sea surface currents to the estimation and modeling of wave energy potential over an area of increased economic interest, the Eastern Mediterranean Sea, is investigated in this work. High-resolution atmospheric, wave, and circulation models, the latter downscaled from the regional Mediterranean Forecasting System (MFS) of the Copernicus marine service (former MyOcean regional MFS system), are utilized towards this goal. The modeled data are analyzed by means of a variety of statistical tools measuring the potential changes not only in the main wave characteristics, but also in the general distribution of the wave energy and the wave parameters that mainly affect it, when using sea surface currents as a forcing to the wave models. The obtained results prove that the impact of the sea surface currents is quite significant in wave energy-related modeling, as well as temporally and spatially dependent. These facts are revealing the necessity of the utilization of the sea surface currents characteristics in renewable energy studies in conjunction with their meteo-ocean forecasting counterparts.
Simon, Joseph; Polin, Abigail; Lommen, Andrea; Christy, B; Stappers, Ben; Finn, Lee Samuel; Jenet, F. A.
2014-03-20
The steadily improving sensitivity of pulsar timing arrays (PTAs) suggests that gravitational waves (GWs) from supermassive black hole binary (SMBHB) systems in the nearby universe will be detectable sometime during the next decade. Currently, PTAs assume an equal probability of detection from every sky position, but as evidence grows for a non-isotropic distribution of sources, is there a most likely sky position for a detectable single source of GWs? In this paper, a collection of Galactic catalogs is used to calculate various metrics related to the detectability of a single GW source resolvable above a GW background, assuming that every galaxy has the same probability of containing an SMBHB. Our analyses of these data reveal small probabilities that one of these sources is currently in the PTA band, but as sensitivity is improved regions of consistent probability density are found in predictable locations, specifically around local galaxy clusters.
Exploring Classically Chaotic Potentials with a Matter Wave Quantum Probe
Gattobigio, G. L.; Couvert, A.; Georgeot, B.; Guery-Odelin, D.
2011-12-16
We study an experimental setup in which a quantum probe, provided by a quasimonomode guided atom laser, interacts with a static localized attractive potential whose characteristic parameters are tunable. In this system, classical mechanics predicts a transition from regular to chaotic behavior as a result of the coupling between the different degrees of freedom. Our experimental results display a clear signature of this transition. On the basis of extensive numerical simulations, we discuss the quantum versus classical physics predictions in this context. This system opens new possibilities for investigating quantum scattering, provides a new testing ground for classical and quantum chaos, and enables us to revisit the quantum-classical correspondence.
On the Quantum Potential and Pulsating Wave Packet in the Harmonic Oscillator
Dubois, Daniel M.
2008-10-17
A fundamental mathematical formalism related to the Quantum Potential factor, Q, is presented in this paper. The Schroedinger equation can be transformed to two equations depending on a group velocity and a density of presence of the particle. A factor, in these equations, was called ''Quantum Potential'' by D. Bohm and B. Hiley. In 1999, I demonstrated that this Quantum Potential, Q, can be split in two Quantum Potentials, Q{sub 1}, and Q{sub 2}, for which the relation, Q=Q{sub 1}+Q{sub 2}, holds. These two Quantum Potentials depend on a fundamental new variable, what I called a phase velocity, u, directly related to the probability density of presence of the wave-particle, given by the modulus of the wave function. This paper gives some further developments for explaining the Quantum Potential for oscillating and pulsating Gaussian wave packets in the Harmonic Oscillator. It is shown that the two Quantum Potentials play a central role in the interpretation of quantum mechanics. A breakthrough in the formalism of the Quantum Mechanics could be provoked by the physical properties of these Quantum Potentials. The probability density of presence of the oscillating and pulsating Gaussian wave packets in the Harmonic Oscillator is directly depending on the ratio Q{sub 2}/Q{sub 1} of the two Quantum Potentials. In the general case, the energy of these Gaussian wave packets is not constant, but is oscillating. The energy is given by the sum of the kinetic energy, T, the potential energy, V, and the two Quantum Potentials: E=T+V+Q{sub 1}+Q{sub 2}. For some conditions, given in the paper, the energy can be a constant. The first remarkable result is the fact that the first Quantum Potential, Q{sub 1}, is related to the ground state energy, E{sub 0}, of the Quantum Harmonic Oscillator: Q{sub 1}=h-bar {omega}/2=E{sub 0}. The second result is related to the property of the second Quantum Potential, Q{sub 2}, which plays the role of an anti-potential, Q{sub 2}=-V(x), where V is
Lundgreen, Kirsten; Lian, Oystein Bjerkestrand; Engebretsen, Lars; Scott, Alex
2013-12-01
Rotator cuff tears are associated with secondary rotator cuff muscle pathology, which is definitive for the prognosis of rotator cuff repair. There is little information regarding the early histological and immunohistochemical nature of these muscle changes in humans. We analyzed muscle biopsies from patients with supraspinatus tendon tears. Supraspinatus muscle biopsies were obtained from 24 patients undergoing arthroscopic repair of partial- or full-thickness supraspinatus tendon tears. Tissue was formalin-fixed and processed for histology (for assessment of fatty infiltration and other degenerative changes) or immunohistochemistry (to identify satellite cells (CD56+), proliferating cells (Ki67+), and myofibers containing predominantly type 1 or 2 myosin heavy chain (MHC)). Myofiber diameters and the relative content of MHC1 and MHC2 were determined morphometrically. Degenerative changes were present in both patient groups (partial and full-thickness tears). Patients with full-thickness tears had a reduced density of satellite cells, fewer proliferating cells, atrophy of MHC1+ and MHC2+ myofibers, and reduced MHC1 content. Full-thickness tears show significantly reduced muscle proliferative capacity, myofiber atrophy, and loss of MHC1 content compared to partial-thickness supraspinatus tendon tears.
Dynamical Control of Matter-Wave Tunneling in Periodic Potentials
NASA Astrophysics Data System (ADS)
Lignier, H.; Sias, C.; Ciampini, D.; Singh, Y.; Zenesini, A.; Morsch, O.; Arimondo, E.
2007-11-01
We report on measurements of dynamical suppression of interwell tunneling of a Bose-Einstein condensate (BEC) in a strongly driven optical lattice. The strong driving is a sinusoidal shaking of the lattice corresponding to a time-varying linear potential, and the tunneling is measured by letting the BEC freely expand in the lattice. The measured tunneling rate is reduced and, for certain values of the shaking parameter, completely suppressed. Our results are in excellent agreement with theoretical predictions. Furthermore, we have verified that, in general, the strong shaking does not destroy the phase coherence of the BEC, opening up the possibility of realizing quantum phase transitions by using the shaking strength as the control parameter.
Matter-wave solitons in radially periodic potentials.
Baizakov, Bakhtiyor B; Malomed, Boris A; Salerno, Mario
2006-12-01
We investigate two-dimensional (2D) states in Bose-Einstein condensates with self-attraction or self-repulsion, trapped in an axially symmetric optical-lattice potential periodic along the radius. The states trapped both in the central potential well and in remote circular troughs are studied. In the repulsive mode, a new soliton species is found, in the form of radial gap solitons. The latter solitons are completely stable if they carry zero vorticity (l=0) , while with l not equal 0 they develop a weak azimuthal modulation, which makes them rotating patterns, that persist indefinitely long. In addition, annular gap solitons may support stable azimuthal dark-soliton pairs on their crests. In remote troughs of the attractive model, stable localized states may assume a ringlike shape with weak azimuthal modulation, or shrink into solitons strongly localized in the azimuthal direction, which is explained in the framework of an averaged 1D equation with the cyclic azimuthal coordinate. Numerical simulations of the attractive model also reveal stable necklacelike patterns, built of several strongly localized peaks. Dynamics of strongly localized solitons circulating in the troughs is studied too. While the solitons with sufficiently small velocities are completely stable, fast solitons gradually decay, due to the leakage of matter into the adjacent trough, under the action of the centrifugal force. Investigation of head-on collisions between strongly localized solitons traveling in circular troughs shows that collisions between in-phase solitons in a common trough lead to collapse, while pi-out-of-phase solitons bounce many times, but eventually merge into a single one, without collapsing. In-phase solitons colliding in adjacent circular troughs also tend to merge into a single soliton.
Matter-wave solitons in radially periodic potentials
Baizakov, Bakhtiyor B.; Malomed, Boris A.; Salerno, Mario
2006-12-15
We investigate two-dimensional (2D) states in Bose-Einstein condensates with self-attraction or self-repulsion, trapped in an axially symmetric optical-lattice potential periodic along the radius. The states trapped both in the central potential well and in remote circular troughs are studied. In the repulsive mode, a new soliton species is found, in the form of radial gap solitons. The latter solitons are completely stable if they carry zero vorticity (l=0), while with l{ne}0 they develop a weak azimuthal modulation, which makes them rotating patterns, that persist indefinitely long. In addition, annular gap solitons may support stable azimuthal dark-soliton pairs on their crests. In remote troughs of the attractive model, stable localized states may assume a ringlike shape with weak azimuthal modulation, or shrink into solitons strongly localized in the azimuthal direction, which is explained in the framework of an averaged 1D equation with the cyclic azimuthal coordinate. Numerical simulations of the attractive model also reveal stable necklacelike patterns, built of several strongly localized peaks. Dynamics of strongly localized solitons circulating in the troughs is studied too. While the solitons with sufficiently small velocities are completely stable, fast solitons gradually decay, due to the leakage of matter into the adjacent trough, under the action of the centrifugal force. Investigation of head-on collisions between strongly localized solitons traveling in circular troughs shows that collisions between in-phase solitons in a common trough lead to collapse, while {pi}-out-of-phase solitons bounce many times, but eventually merge into a single one, without collapsing. In-phase solitons colliding in adjacent circular troughs also tend to merge into a single soliton.
NASA Astrophysics Data System (ADS)
Feist, B. E.; Fuller, E.; Plummer, M. L.
2016-12-01
Conversion to renewable energy sources is a logical response to increasing pressure to reduce greenhouse gas emissions. Ocean wave energy is the least developed renewable energy source, despite having the highest energy per unit area. While many hurdles remain in developing wave energy, assessing potential conflicts and evaluating tradeoffs with existing uses is essential. Marine planning encompasses a broad array of activities that take place in and affect large marine ecosystems, making it an ideal tool for evaluating wave energy resource use conflicts. In this study, we focus on the potential conflicts between wave energy conversion (WEC) facilities and existing marine uses in the context of marine planning, within the California Current Large Marine Ecosystem. First, we evaluated wave energy facility development using the Wave Energy Model (WEM) of the Integrated Valuation of Ecosystem Services and Trade-offs (InVEST) toolkit. Second, we ran spatial analyses on model output to identify conflicts with existing marine uses including AIS based vessel traffic, VMS and observer based measures of commercial fishing effort, and marine conservation areas. We found that regions with the highest wave energy potential were distant from major cities and that infrastructure limitations (cable landing sites) restrict integration with existing power grids. We identified multiple spatial conflicts with existing marine uses; especially shipping vessels and various commercial fishing fleets, and overlap with marine conservation areas varied by conservation designation. While wave energy generation facilities may be economically viable in the California Current, this viability must be considered within the context of the costs associated with conflicts that arise with existing marine uses. Our analyses can be used to better inform placement of WEC devices (as well as other types of renewable energy facilities) in the context of marine planning by accounting for economic tradeoffs
Electromagnetic wave emitting products and "Kikoh" potentiate human leukocyte functions.
Niwa, Y; Iizawa, O; Ishimoto, K; Jiang, X; Kanoh, T
1993-09-01
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.
Electromagnetic wave emitting products and ``Kikoh'' potentiate human leukocyte functions
NASA Astrophysics Data System (ADS)
Niwa, Yukie; Iizawa, Osamu; Ishimoto, Koichi; Jiang, Xiaoxia; Kanoh, Tadashi
1993-09-01
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 µm). 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.
Support vector machine for evaluating seismic-liquefaction potential using shear wave velocity
NASA Astrophysics Data System (ADS)
Samui, Pijush; Kim, Dookie; Sitharam, T. G.
2011-01-01
The use of the shear wave velocity data as a field index for evaluating the liquefaction potential of sands is receiving increased attention because both shear wave velocity and liquefaction resistance are similarly influenced by many of the same factors such as void ratio, state of stress, stress history and geologic age. In this paper, the potential of support vector machine (SVM) based classification approach has been used to assess the liquefaction potential from actual shear wave velocity data. In this approach, an approximate implementation of a structural risk minimization (SRM) induction principle is done, which aims at minimizing a bound on the generalization error of a model rather than minimizing only the mean square error over the data set. Here SVM has been used as a classification tool to predict liquefaction potential of a soil based on shear wave velocity. The dataset consists the information of soil characteristics such as effective vertical stress (σ‧v0), soil type, shear wave velocity (Vs) and earthquake parameters such as peak horizontal acceleration (amax) and earthquake magnitude (M). Out of the available 186 datasets, 130 are considered for training and remaining 56 are used for testing the model. The study indicated that SVM can successfully model the complex relationship between seismic parameters, soil parameters and the liquefaction potential. In the model based on soil characteristics, the input parameters used are σ‧v0, soil type, Vs, amax and M. In the other model based on shear wave velocity alone uses Vs, amax and M as input parameters. In this paper, it has been demonstrated that Vs alone can be used to predict the liquefaction potential of a soil using a support vector machine model.
Rodriguez-Falces, Javier; Duchateau, Jacques; Muraoka, Yoshiho; Baudry, Stéphane
2015-04-15
The study was undertaken to provide insight into the mechanisms underlying the potentiation of the muscle compound action potential (M wave) after conditioning contractions. M waves were evoked in the tibialis anterior before and after isometric maximal voluntary contractions (MVC) of 1, 3, 6, 10, 30, and 60 s, and after 3-s contractions at 10, 30, 50, 70, 90, and 100% MVC. The amplitude, duration, and area of the first and second phases of the M wave, together with the median frequency (Fmedian) and muscle fiber conduction velocity (MFCV) were recorded. Furthermore, twitch force, muscle fascicle length, and pennation angle were measured at rest, before, and 1 s after the conditioning contractions. The results indicate that only the amplitude of the second phase of the M wave was significantly increased after conditioning contractions. The extent of this potentiation was similar for MVC durations ranging from 1 to 10 s and augmented progressively with contraction intensity from 30 to 70% MVC. After these conditioning contractions, the duration and area of the two M-wave phases decreased (P < 0.05), whereas MFCV and Fmedian increased (P < 0.05). For all of these parameters, the greatest changes occurred 1 s after the conditioning contraction. Changes in MFCV after the contractions were correlated with those in M-wave second-phase amplitude (r(2) = 0.42; P < 0.05) and Fmedian (r(2) = 0.53; P < 0.05). In contrast, fascicle length and pennation angle did not change after the conditioning contractions. It is concluded that the potentiation of the second phase of the M wave is mainly due to an increased MFCV. Copyright © 2015 the American Physiological Society.
Some Exact Results for the Schroedinger Wave Equation with a Time Dependent Potential
NASA Technical Reports Server (NTRS)
Campbell, Joel
2009-01-01
The time dependent Schroedinger equation with a time dependent delta function potential is solved exactly for many special cases. In all other cases the problem can be reduced to an integral equation of the Volterra type. It is shown that by knowing the wave function at the origin, one may derive the wave function everywhere. Thus, the problem is reduced from a PDE in two variables to an integral equation in one. These results are used to compare adiabatic versus sudden changes in the potential. It is shown that adiabatic changes in the p otential lead to conservation of the normalization of the probability density.
Bulut, Niyazi; Kłos, Jacek; Alexander, Millard H
2012-03-14
We present converged exact quantum wave packet calculations of reaction probabilities, integral cross sections, and thermal rate coefficients for the title reaction. Calculations have been carried out on the ground 1(2)A' global adiabatic potential energy surface of Deskevich et al. [J. Chem. Phys. 124, 224303 (2006)]. Converged wave packet reaction probabilities at selected values of the total angular momentum up to a partial wave of J = 140 with the HCl reagent initially selected in the v = 0, j = 0-16 rovibrational states have been obtained for the collision energy range from threshold up to 0.8 eV. The present calculations confirm an important enhancement of reactivity with rotational excitation of the HCl molecule. First, accurate integral cross sections and rate constants have been calculated and compared with the available experimental data.
Potential to kinetic energy conversion in wave number domain for the Southern Hemisphere
NASA Technical Reports Server (NTRS)
Huang, H.-J.; Vincent, D. G.
1984-01-01
Preliminary results of a wave number study conducted for the South Pacific Convergence Zone (SPCZ) using FGGE data for the period January 10-27, 1979 are reported. In particular, three variables (geomagnetic height, z, vertical p-velocity, omega, and temperature, T) and one energy conversion quantity, omega-alpha (where alpha is the specific volume), are shown. It is demonstrated that wave number 4 plays an important role in the conversion from available potential energy to kinetic energy in the Southern Hemisphere tropics, particularly in the vicinity of the SPCZ. It is therefore suggested that the development and movement of wave number 4 waves be carefully monitored in making forecasts for the South Pacific region.
Luck, Steven J.; Kappenman, Emily S.; Fuller, Rebecca L.; Robinson, Benjamin; Summerfelt, Ann; Gold, James M.
2008-01-01
Reaction times (RTs) are substantially prolonged in schizophrenia patients, but the latency of the P3 component is not. This suggests that the RT slowing arises from impairments in a late stage of processing. To test this hypothesis, 20 schizophrenia patients and 20 control subjects were tested in a visual oddball paradigm that was modified to allow measurement of the lateralized readiness potential (LRP), an index of stimulus-response translation processes. Difference waves were used to isolate the LRP and the P3 wave. Patients and control subjects exhibited virtually identical P3 difference waves, whereas the LRP difference wave was reduced in amplitude and delayed in latency in the patients. These results indicate that, at least in simple tasks, the delayed RTs observed in schizophrenia are primarily a consequence of impairments in the response selection and preparation processes that follow perception and categorization. PMID:19386044
Potential of ion cyclotron resonance frequency current drive via fast waves in DEMO
NASA Astrophysics Data System (ADS)
Kazakov, Ye O.; Van Eester, D.; Wauters, T.; Lerche, E.; Ongena, J.
2015-02-01
For the continuous operation of future tokamak-reactors like DEMO, non-inductively driven toroidal plasma current is needed. Bootstrap current, due to the pressure gradient, and current driven by auxiliary heating systems are currently considered as the two main options. This paper addresses the current drive (CD) potential of the ion cyclotron resonance frequency (ICRF) heating system in DEMO-like plasmas. Fast wave CD scenarios are evaluated for both the standard midplane launch and an alternative case of exciting the waves from the top of the machine. Optimal ICRF frequencies and parallel wave numbers are identified to maximize the CD efficiency. Limitations of the high frequency ICRF CD operation are discussed. A simplified analytical method to estimate the fast wave CD efficiency is presented, complemented with the discussion of its dependencies on plasma parameters. The calculated CD efficiency for the ICRF system is shown to be similar to those for the negative neutral beam injection and electron cyclotron resonance heating.
Potential to kinetic energy conversion in wave number domain for the Southern Hemisphere
NASA Technical Reports Server (NTRS)
Huang, H.-J.; Vincent, D. G.
1984-01-01
Preliminary results of a wave number study conducted for the South Pacific Convergence Zone (SPCZ) using FGGE data for the period January 10-27, 1979 are reported. In particular, three variables (geomagnetic height, z, vertical p-velocity, omega, and temperature, T) and one energy conversion quantity, omega-alpha (where alpha is the specific volume), are shown. It is demonstrated that wave number 4 plays an important role in the conversion from available potential energy to kinetic energy in the Southern Hemisphere tropics, particularly in the vicinity of the SPCZ. It is therefore suggested that the development and movement of wave number 4 waves be carefully monitored in making forecasts for the South Pacific region.
Partial Testing Can Potentiate Learning of Tested and Untested Material from Multimedia Lessons
ERIC Educational Resources Information Center
Yue, Carole L.; Soderstrom, Nicholas C.; Bjork, Elizabeth Ligon
2015-01-01
Test-potentiated learning occurs when testing renders a subsequent study period more effective than it would have been without an intervening test. We examined whether testing only a subset of material from a multimedia lesson would potentiate the restudy of both tested and untested material. In Experiments 1a and 1b, participants studied a…
Partial Testing Can Potentiate Learning of Tested and Untested Material from Multimedia Lessons
ERIC Educational Resources Information Center
Yue, Carole L.; Soderstrom, Nicholas C.; Bjork, Elizabeth Ligon
2015-01-01
Test-potentiated learning occurs when testing renders a subsequent study period more effective than it would have been without an intervening test. We examined whether testing only a subset of material from a multimedia lesson would potentiate the restudy of both tested and untested material. In Experiments 1a and 1b, participants studied a…
On Floating Potential of Emissive Probes in a Partially-Magnetized Plasma
NASA Astrophysics Data System (ADS)
Raitses, Yevgeny; Kraus, Brian
2016-10-01
We compare measurements of plasma potential in a cross-field Penning discharge from two probes: swept biased Langmuir probe and floating emissive probe. The plasma potential was deduced from the first derivative of the Langmuir probe characteristic. In previous studies, the emissive and swept biased probes were placed at the channel exit of a Hall thruster (HT). Measurements showed that the emissive probe floats below the plasma potential, in agreement with conventional theories. However, recent measurements in the Penning discharge indicate a floating potential of a strongly-emitting hot probe above the plasma potential. In both probe applications, xenon plasmas have magnetized electrons and non-magnetized ions with similar plasma densities (1010 - 1011 cm-3) . Though their electron temperatures differ by an order of magnitude (Penning 5 eV, HT 50 eV), this difference cannot explain the difference in measurement values of the hot floating potential because both temperatures are much higher than the emitting wire. In this work, we investigate how the ion velocity and other plasma parameters affect this discrepancy between probe measurements of the plasma potential. This work was supported by DOE contract DE-AC02-09CH11466.
NASA Astrophysics Data System (ADS)
Alifdini, I.; Sugianto, D. N.; Andrawina, Y. O.; Widodo, A. B.
2017-02-01
Pulau Baai is a beach which is located in Bengkulu, Indonesia. This location has swell waves which is beneficial for wave energy, because it directly faces the Indian Ocean. Floating Oscillating Water Column (OWC) is a prototype used to generate electricity from wave energy. The objective of this research is to identify how much electricity can be generated from floating OWC. This research used a quantitative method by processing wind data (speed and direction) from ogimet.com in 2000-2016. The wind speed rate for wave energy potential of this location is above 5.14 m/s. Wind data is converted to significant wave height and periods data by Sverdrup, Munk, and Bretschneider (SMB) method. Significant wave height rate of this location is 0.06 – 5.33 meters. Assuming that this power plant uses 3 chambers of floating OWC, the power output of OWC is 1.9 GW/year. Thus, suppose each residents’ house uses 1300 watt, this power plant can be used for 1,461,538 residents per year.
Scaling laws of reflection coefficients of quantum waves at a Cantor-like potential
NASA Astrophysics Data System (ADS)
Sakaguchi, Hidetsugu; Ogawana, Taichi
2017-03-01
We reconsider a one-dimensional scattering problem in the Schrödinger equation with a Cantor-like potential. The reflection coefficient obeys a scaling law for sufficiently large wave number k . The scaling law is expressed with a universal function characterized by a multifractal.
Scaling laws of reflection coefficients of quantum waves at a Cantor-like potential.
Sakaguchi, Hidetsugu; Ogawana, Taichi
2017-03-01
We reconsider a one-dimensional scattering problem in the Schrödinger equation with a Cantor-like potential. The reflection coefficient obeys a scaling law for sufficiently large wave number k. The scaling law is expressed with a universal function characterized by a multifractal.
The Potential Energy Density in Transverse String Waves Depends Critically on Longitudinal Motion
ERIC Educational Resources Information Center
Rowland, David R.
2011-01-01
The question of the correct formula for the potential energy density in transverse waves on a taut string continues to attract attention (e.g. Burko 2010 "Eur. J. Phys." 31 L71), and at least three different formulae can be found in the literature, with the classic text by Morse and Feshbach ("Methods of Theoretical Physics" pp 126-127) stating…
Airy wave packet for a particle in a time-dependent linear potential
NASA Astrophysics Data System (ADS)
Berrehail, Mounira; Benchiheub, Nadjet
2017-01-01
We studied the quantum motion of a particle in the presence of a time-dependent linear potential by using an operator invariant that is quadratic in p and linear in x within the framework of the Lewis-Riesenfeld invariant. The special invariant operator in this work is demonstrated to be Hermitian operator that has an Airy wave packet as its eigenfunctions.
The Potential Energy Density in Transverse String Waves Depends Critically on Longitudinal Motion
ERIC Educational Resources Information Center
Rowland, David R.
2011-01-01
The question of the correct formula for the potential energy density in transverse waves on a taut string continues to attract attention (e.g. Burko 2010 "Eur. J. Phys." 31 L71), and at least three different formulae can be found in the literature, with the classic text by Morse and Feshbach ("Methods of Theoretical Physics" pp 126-127) stating…
Scattering of quantum wave packets by shallow potential islands: a quantum lens.
Goussev, Arseni; Richter, Klaus
2013-05-01
We consider the problem of quantum scattering of a localized wave packet by a weak Gaussian potential in two spatial dimensions. We show that, under certain conditions, this problem bears close analogy with that of focusing (or defocusing) of light rays by a thin optical lens: Quantum interference between straight paths yields the same lens equation as for refracted rays in classical optics.
Pietrzak, Robert H.; Goldstein, Risë B.; Southwick, Steven M.; Grant, Bridget F.
2011-01-01
Objective This study examined associations between lifetime trauma exposures, PTSD and partial PTSD, and past-year medical conditions in a nationally representative sample of U.S. adults. Methods Face-to-face interviews were conducted with 34,653 participants in the Wave 2 National Epidemiologic Survey on Alcohol and Related Conditions. Logistic regression analyses evaluated associations of trauma exposure, PTSD and partial PTSD with respondent-reported medical diagnoses. Results After adjustment for sociodemographic characteristics and comorbid Axis I and II disorders, respondents with full PTSD were more likely than traumatized respondents without full or partial PTSD (comparison group) to report diagnoses of diabetes mellitus, noncirrhotic liver disease, angina pectoris, tachycardia, hypercholesterolemia, other heart disease, stomach ulcer, HIV seropositivity, gastritis, and arthritis (odds ratios [ORs]=1.2-2.5). Respondents with partial PTSD were more likely than the comparison group to report past-year diagnoses of stomach ulcer, angina pectoris, tachycardia, and arthritis (ORs=1.3-1.6). Men with full and partial PTSD were more likely than controls to report diagnoses of hypertension (both ORs=1.6), and both men and women with PTSD (ORs=1.8 and 1.6, respectively), and men with partial PTSD (OR=2.0) were more likely to report gastritis. Total number of lifetime traumatic event types was associated with many assessed medical conditions (ORs=1.04-1.16), reducing the magnitudes and rendering non-significant some of the associations between PTSD status and medical conditions. Conclusions Greater lifetime trauma exposure and PTSD are associated with numerous medical conditions, many of which are stress-related and chronic, in U.S. adults. Partial PTSD is associated with intermediate odds of some of these conditions. PMID:21949429
Determining wave resistance of a ship using a dissipative potential flow model
NASA Astrophysics Data System (ADS)
Fürth, Mirjam; Tan, Mingyi; Chen, Zhi-Min
2013-11-01
Potential flow modelling is a common method to predict the wave resistance of ships. In its conventional form the flow is assumed to be free from damping due to the inviscid assumption of potential flow. However, it is evident by just looking at waves that they decay with time and distance. It is a reasonable assumption that, by including more of the actual physical aspect in mathematical model, the quality of the prediction will improve. As Havelock wrote almost 80 years ago ``It seems fairly certain that one of the main causes of differences between theoretical and experimental result is the neglect of fluid friction in the calculation of ship waves.'' In this study, the problem is modelled using Kelvin sources with a translating speed. Rayleigh damping is introduced in the model to emulate viscous damping. To calculate the source influences, a dissipative 3D Green function is derived. For initial validation of the Green function, thin ship theory is used to determine the wave pattern behind a Wigley hull and a modified form of the Eggers et al. transverse cut technique is used to calculate the wave resistance. To evaluate the method for fuller and more realistic hull shapes a panel method which calculates the resistance via the pressure on the ship hull is used. This project is sponsored by Lloyds Register Foundation, their support is greatly appreciated.
Four-wave mixing microscopy: a high potential nonlinear imaging method
NASA Astrophysics Data System (ADS)
Ehmke, Tobias; Knebl, Andreas; Heisterkamp, Alexander
2015-03-01
In this work we present non-resonant four-wave mixing microscopy as an additional contrast mechanism in nonlinear microscopy. The setup for this technique was based on a commercially available multiphoton microscope setup equipped with a titanium:sapphire-laser and an optical parametric oscillator as light sources. Fundamental system characteristics with respect to the spatio-temporal pulse overlap and the influence of aberrations on the process are presented. Experiments regarding the directionality of the four-wave mixing signal performed on fresh porcine meat showed an average ratio of the backward to forward signal mean intensity of 0.16 +/- 0.01. Nevertheless, structural information is comparable for both detection modalities. This highlights the potential of four-wave mixing microscopy for in vivo applications. Furthermore, results on porcine meat show the additional contrast generated by four-wave mixing. In summary, the results show a great potential of non-resonant four-wave mixing microscopy as label-free imaging modality in the biomedical sciences.
Matter-wave exact periodic solutions in optical lattices with periodic potential
NASA Astrophysics Data System (ADS)
Liu, Changfu; Zhu, Aijun
2013-10-01
Some special matter-wave periodic solutions for the Gross-Pitaevskii equation with periodic potential in the multidimensional optical lattices, are obtained through restricting parameters and some balance conditions between the optical potentials and interaction energies. The results show that the same type of periodic solutions in the same dimension possesses the same norm but different phases and they are all bounded. Especially, the numerics shows that two class (2+1)-dimensional periodic solutions are stable.
The importance of wave break events for synoptic scale buildups of zonal available potential energy
NASA Astrophysics Data System (ADS)
Bowley, K.; Gyakum, J. R.; Atallah, E.
2016-12-01
Zonal available potential energy (ZAPE) is an estimate of the amount of potential energy in the atmosphere available for conversion to kinetic energy, providing a good proxy for the strength of the general circulation. Previous studies have estimated total hemispheric ZAPE, ZAPE generation, and conversion to kinetic energy, and proposed physical mechanisms to describe the annual ZAPE cycle as well as short term (sub-seasonal to synoptic) APE depletion events. Large short term depletions of ZAPE have been attributed to synoptic scale processes including intense mid-latitude cyclones which are often associated with cyclonic (LC2) wave break events on the dynamic tropopause. However, increases in ZAPE on similar time scales have not been examined in detail. In this study, we examine the association of significant synoptic time-scale increases in ZAPE with dynamic tropopause wave break events. ZAPE buildup events are determined using a 1979-2011 daily Northern Hemisphere (20°-85°N) ZAPE climatology calculated from the NCEP Reanalysis-2 dataset in an isobaric framework. Build-up events are identified using a standardized anomaly (SA) technique, where the SA of ZAPE must increase by at least 2σ in a near-continuous manner for a 3-10 day period. To diagnose the importance of wave breaks in the troposphere, we objectively identify wave breaks using potential temperature on the dynamic tropopause, identifying both anti-cyclonic (LC1) and cyclonic (LC2) wave breaks during the 1979-2011 period. Our results indicate that LC1 wave break events appear to play an important role in ZAPE buildup events. In particular, the analysis of winter buildup events indicate that LC1 wave break events occur more frequently in the equatorward exit regions of the North Pacific and North Atlantic jet streams when compared with climatology. The formation of these wave break events result in the development of statistically significant warm-core high pressure anomalies in these regions, acting
Ambipolar potential effect on a drift-wave mode in a tandem-mirror plasma
Mase, A.; Jeong, J.H.; Itakura, A.; Ishii, K.; Inutake, M.; Miyoshi, S. )
1990-05-07
The {bold k}-{omega} spectra of low-frequency waves which exist in a tandem-mirror plasma are observed by using the Fraunhofer-diffraction method. The observed dispersion relations are in good agreement with those of drift waves including a Doppler shift due to {bold E}{times}{bold B} rotation velocity. The fluctuation level is observed to depend sensitively on the radial profile of a plasma potential. It has a maximum value when a slightly negative electric field is formed, and decreases with increase in an electric field regardless of its sign.
Propagation of matter-wave solitons in periodic and random nonlinear potentials
Abdullaev, Fatkhulla Kh.; Garnier, Josselin
2005-12-15
We study the motion of bright matter-wave solitons in nonlinear potentials, produced by periodic or random spatial variations of the atomic scattering length. We obtain analytical results for the soliton motion, the radiation of matter wave, and the radiative soliton decay in such configurations of the Bose-Einstein condensate. The stable regimes of propagation are analyzed. The results are in remarkable agreement with the numerical simulations of the Gross-Pitaevskii equation with periodic or random spatial variations of the mean field interactions.
Nouri-Nigjeh, Eslam; Permentier, Hjalmar P; Bischoff, Rainer; Bruins, Andries P
2011-07-15
Electrochemistry combined with mass spectrometry (EC-MS) is an emerging analytical technique in the imitation of oxidative drug metabolism at the early stages of new drug development. Here, we present the benefits of electrochemical oxidation by square-wave potential pulses for the oxidation of lidocaine, a test drug compound, on a platinum electrode. Lidocaine was oxidized at constant potential and by square-wave potential pulses with different cycle times, and the reaction products were analyzed by liquid chromatography-mass spectrometry [LC-MS(/MS)]. Application of constant potentials of up to +5.0 V resulted in relatively low yields of N-dealkylation and 4-hydroxylation products, while oxidation by square-wave potential pulses generated up to 50 times more of the 4-hydroxylation product at cycle times between 0.2 and 12 s (estimated yield of 10%). The highest yield of the N-dealkylation product was obtained at cycle times shorter than 0.2 s. Tuning of the cycle time is thus an important parameter to modulate the selectivity of electrochemical oxidation reactions. The N-oxidation product was only obtained by electrochemical oxidation under air atmosphere due to reaction with electrogenerated hydrogen peroxide. Square-wave potential pulses may also be applicable to modulate the selectivity of electrochemical reactions with other drug compounds in order to generate oxidation products with greater selectivity and higher yield based on the optimization of cycle times and potentials. This considerably widens the scope of direct electrochemistry-based oxidation reactions for the imitation of in vivo oxidative drug metabolism.
Ouyang, Zi; Mainali, Madan Kumar; Sinha, Neeharika; Strack, Guinevere; Altundal, Yucel; Hao, Yao; Winningham, Thomas Andrew; Sajo, Erno; Celli, Jonathan; Ngwa, Wilfred
2016-01-01
The purpose of this study is to investigate the feasibility of using cerium oxide nanoparticles (CONPs) as radical scavengers during accelerated partial breast irradiation (APBI) to protect normal tissue. We hypothesize that CONPs can be slowly released from the routinely used APBI balloon applicators—via a degradable coating—and protect the normal tissue on the border of the lumpectomy cavity over the duration of APBI. To assess the feasibility of this approach, we analytically calculated the initial concentration of CONPs required to protect normal breast tissue from reactive oxygen species (ROS) and the time required for the particles to diffuse to various distances from the lumpectomy wall. Given that cerium has a high atomic number, we took into account the possible inadvertent dose enhancement that could occur due to the photoelectric interactions with radiotherapy photons. To protect against a typical MammoSite treatment fraction of 3.4 Gy, 5 ng-g−1 of CONPs is required to scavenge hydroxyl radicals and hydrogen peroxide. Using 2 nm sized NPs, with an initial concentration of 1 mg-g−1, we found that 2–10 days of diffusion is required to obtain desired concentrations of CONPs in regions 1–2 cm away from the lumpectomy wall. The resultant dose enhancement factor (DEF) is less than 1.01 under such conditions. Our results predict that CONPs can be employed for radioprotection during APBI using a new design in which balloon applicators are coated with the NPs for sustained/controlled in-situ release from within the lumpectomy cavity. PMID:27053452
Ouyang, Zi; Mainali, Madan Kumar; Sinha, Neeharika; Strack, Guinevere; Altundal, Yucel; Hao, Yao; Winningham, Thomas Andrew; Sajo, Erno; Celli, Jonathan; Ngwa, Wilfred
2016-04-01
The purpose of this study is to investigate the feasibility of using cerium oxide nanoparticles (CONPs) as radical scavengers during accelerated partial breast irradiation (APBI) to protect normal tissue. We hypothesize that CONPs can be slowly released from the routinely used APBI balloon applicators-via a degradable coating-and protect the normal tissue on the border of the lumpectomy cavity over the duration of APBI. To assess the feasibility of this approach, we analytically calculated the initial concentration of CONPs required to protect normal breast tissue from reactive oxygen species (ROS) and the time required for the particles to diffuse to various distances from the lumpectomy wall. Given that cerium has a high atomic number, we took into account the possible inadvertent dose enhancement that could occur due to the photoelectric interactions with radiotherapy photons. To protect against a typical MammoSite treatment fraction of 3.4Gy, 5ng·g(-1) of CONPs is required to scavenge hydroxyl radicals and hydrogen peroxide. Using 2nm sized NPs, with an initial concentration of 1mg·g(-1), we found that 2-10days of diffusion is required to obtain desired concentrations of CONPs in regions 1-2cm away from the lumpectomy wall. The resultant dose enhancement factor (DEF) is less than 1.01 under such conditions. Our results predict that CONPs can be employed for radioprotection during APBI using a new design in which balloon applicators are coated with the NPs for sustained/controlled in-situ release from within the lumpectomy cavity.
Burlak, Gennadiy; Malomed, Boris A
2012-05-01
We report results of systematic numerical studies of two-dimensional matter-wave soliton families supported by an external potential, in a vicinity of the junction between stable and unstable branches of the families, where the norm of the solution attains a minimum, facilitating the creation of the soliton. The model is based on the Gross-Pitaevskii equation for the self-attractive condensate loaded into a quasiperiodic (QP) optical lattice (OL). The same model applies to spatial optical solitons in QP photonic crystals. Dynamical properties and stability of the solitons are analyzed with respect to variations of the depth and wave number of the OL. In particular, it is found that the single-peak solitons are stable or not in exact accordance with the Vakhitov-Kolokolov (VK) criterion, while double-peak solitons, which are found if the OL wave number is small enough, are always unstable against splitting.
NASA Astrophysics Data System (ADS)
Schreyer, L. G.; Addassi, M.; Johannesson, B.; Lin, H.
2016-12-01
Vapor transport in variably saturated soils is traditionally modeled using a system of equations including the conservation of mass, multiphase Darcy equation, and a version of the Philip and deVries equation for heat transfer. Typically the continuity equations and multiphase Darcy equation are combined to form one equation with one unknown, usually moisture content or capillary pressure. Here we introduce chemical potential as an alternate dependent variable and show that it simplifies conceptually and mathematically the modeling of vapor transport. Here we revisit the fundamentals of chemical potential, provide a simple one-dimensional pore-scale model, and compare the model with experimental results. In the process we explain simply the physics of enhanced diffusion due to liquid bridges.
The asymmetric Hubbard model with a confining potential: The partial filling case
NASA Astrophysics Data System (ADS)
Silva-Valencia, J.; Franco, R.; Figueira, M. S.
We investigate the one-dimensional asymmetric Hubbard model with a confining potential, which may describe the ground state of two species of fermionic atoms trapped in a one-dimensional optical lattice. We use White's density matrix renormalization group and the global electronic density considered is n=0.8. The fermion density profiles and their variance were computed. We observe coexistence of insulating and metallic regions in the system. The effective confinement region is different for each kind of fermionic atom.
ENSO-Related Variability in Wave Climate Drives Greater Erosion Potential on Central Pacific Atolls
NASA Astrophysics Data System (ADS)
Bramante, J. F.; Ashton, A. D.; Donnelly, J. P.
2015-12-01
The El Nino Southern Oscillation (ENSO) modulates atmospheric circulation across the equatorial Pacific over a periodic time scale of 2-7 years. Despite the importance of this climate mode in forcing storm generation and trade wind variability, its impact on the wave climate incident on central Pacific atolls has not been addressed. We used the NOAA Wavewatch III CFSR reanalysis hindcasts (1979-2007) to examine the influence of ENSO on sediment mobility and transport at Kwajalein Atoll (8.8°N, 167.7°E). We found that during El Nino event years, easterly trade winds incident on the atoll weakened by 4% compared to normal years and 17% relative to La Nina event years. Despite this decrease in wind strength, significant wave heights incident on the atoll were 3-4% greater during El Nino event years. Using machine learning to partition these waves revealed that the greater El Nino wave heights originated mainly from greater storm winds near the atoll. The southeastern shift in tropical cyclone genesis location during El Nino years forced these storm winds and contributed to the 7% and 16% increases in annual wave energy relative to normal and La Nina years, respectively. Using nested SWAN and XBeach models we determined that the additional wave energy during El Nino event years significantly increased potential sediment mobility at Kwajalein Atoll and led to greater net offshore transport on its most populous island. The larger storm waves likely deplete ocean-facing beaches and reef flats of sediment, but increase the supply of sediment to the atoll lagoon across open reef platforms that are not supporting islands. We discuss further explicit modelling of storms passing over the atoll to elucidate the confounding role of storm surge on the net erosional/depositional effects of these waves. Extrapolating our results to recent Wavewatch III forecasts leads us to conclude that climate change-linked increases in wave height and storm wave energy will increase erosion on
Mitri, F
2014-12-01
Stemming from the Rayleigh-Sommerfeld surface integral, the addition theorems for the spherical wave and Legendre functions, and a weighting function describing the behavior of the radial component vp1 of the normal velocity at the surface of a finite circular radiating source, partial-wave series expansions are derived for the incident field of acoustic spiraling (vortex) beams in a spherical coordinate system centered on the axis of wave propagation. Examples for vortex beams, comprising ρ-vortex, zeroth-order and higher order Bessel-Gauss and Bessel, truncated Neumann-Gauss and Hankel- Gauss, Laguerre-Gauss, and other Gaussian-type vortex beams are considered. The mathematical expressions are exact solutions of the Helmholtz equation. The results presented here are particularly useful to accurately evaluate analytically and compute numerically the acoustic scattering and other mechanical effects of finite vortex beams, such as the axial and 3-D acoustic radiation force and torque components on a sphere of any (isotropic, anisotropic, etc.) material (fluid, elastic, viscoelastic, etc.), either centered on the beam's axis of wave propagation, or placed off-axially. Numerical predictions allow optimal design of parameters in applications including but not limited to acoustical tweezers, acousto-fluidics, beamforming design, and imaging, to name a few.
NASA Astrophysics Data System (ADS)
Ashton, G.; Prix, R.; Jones, D. I.
2017-09-01
Continuous gravitational waves from neutron stars could provide an invaluable resource to learn about their interior physics. A common search method involves matched filtering a modeled template against the noisy gravitational-wave data to find signals. This method suffers a mismatch (i.e., relative loss of the signal-to-noise ratio) if the signal deviates from the template. One possible instance in which this may occur is if the neutron star undergoes a glitch, a sudden rapid increase in the rotation frequency seen in the timing of many radio pulsars. In this work, we use a statistical characterization of the glitch rate and size in radio pulsars to estimate how often neutron star glitches would occur within the parameter space of continuous gravitational-wave searches and how much mismatch putative signals would suffer in the search due to these glitches. We find that for many previous and potential future searches continuous-wave signals have an elevated probability of undergoing one or more glitches and that these glitches will often lead to a substantial fraction of the signal-to-noise ratio being lost. This could lead to a failure to identify candidate gravitational-wave signals in the initial stages of a search and also to the false dismissal of candidates in subsequent follow-up stages.
NASA Astrophysics Data System (ADS)
Maneva, Yana; Alvarez Laguna, Alejandro; Lani, Andrea; Poedts, Stefaan
2017-04-01
Partial ionization effects related to electron-neutral and ion-neutral interactions play an important role in the weakly ionized solar chromosphere, where the number density of neutrals vastly exceeds the number density of protons. The interactions between the magnetized plasma and the neutral particles can significantly change the resistivity of the plasma and lead to additional heating. Such multi-species interactions cannot be described within the simple MHD single fluid models and the non-equilibrium partial ionization effects cannot be properly captured even when generalized MHD models including Ambipolar diffusion terms are taken into account. A more detailed approach to describe these processes in the solar chromosphere is to use multi-fluid numerical simulations where the neutrals and the plasma species are described as separate fluids, coupled through the chemical reactions, additional currents, friction and resistivity terms. In this study we have elaborate on our previous results and perform 2D two-fluid simulations with an electron-proton fluid and a separate neutral fluid using an improved model where the density and temperature dependence of the plasma viscosities and heat conduction for the neutrals is assumed. Previously we have investigated the chromospheric propagation of fast and slow waves generated by a fixed photospheric foot-point velocity driver. In this study we have varied the velocity driver's frequency and location. We have also distinguished between the types of drivers which excite pure slow/Alfvén waves or a mixture of slow and fast waves. Finally, we have studied the non-uniform heating caused by the waves.
Bent waveguides for matter-waves: supersymmetric potentials and reflectionless geometries
Campo, Adolfo del; Boshier, Malcolm G.; Saxena, Avadh
2014-01-01
Non-zero curvature in a waveguide leads to the appearance of an attractive quantum potential which crucially affects the dynamics in matter-wave circuits. Using methods of supersymmetric quantum mechanics, pairs of bent waveguides are found whose geometry-induced potentials share the same scattering properties. As a result, reflectionless waveguides, dual to the straight waveguide, are identified. Strictly isospectral waveguides are also found by modulating the depth of the trapping potential. Numerical simulations are used to demonstrate the efficiency of these approaches in tailoring and controlling curvature-induced quantum-mechanical effects. PMID:24919423
The role of internal waves in larval fish interactions with potential predators and prey
NASA Astrophysics Data System (ADS)
Greer, Adam T.; Cowen, Robert K.; Guigand, Cedric M.; Hare, Jonathan A.; Tang, Dorothy
2014-09-01
Tidally driven internal wave packets in coastal environments have the potential to influence patchiness of larval fishes, prey, and gelatinous predators. We used the In Situ Ichthyoplankton Imaging System (ISIIS) to synoptically sample larval fishes, copepods, and planktonic predators (ctenophores, hydromedusae, chaetognaths, and polychaetes) across these predictable features in the summer near Stellwagen Bank, Massachusetts, USA. Full water column profiles and fixed depth transects (∼10 m depth) were used to quantify vertical and horizontal components of the fish and invertebrate distributions during stable and vertically mixed conditions associated with tidally generated internal waves. Larval fishes, consisting mostly of Urophycis spp., Merluccius bilinearis, and Labridae, were concentrated near the surface, with larger sizes generally occupying greater depths. During stable water column conditions, copepods formed a near surface thin layer several meters above the chlorophyll-a maximum that was absent when internal waves were propagating. In contrast, ctenophores and other predators were much more abundant at depth, but concentrations near 10 m increased immediately after the internal hydraulic jump mixed the water column. During the propagation of internal waves, the fine-scale abundance of larval fishes was more correlated with the abundance of gelatinous predators and less correlated with copepods compared to the stable conditions. Vertical oscillations caused by the internal hydraulic jump can disperse patches of zooplankton and force surface dwelling larval fishes into deeper water where probability of predator contact is increased, creating conditions potentially less favorable for larval fish growth and survival on short time scales.
Gabrieli, Andrea; Sant, Marco; Demontis, Pierfranco; Suffritti, Giuseppe B
2015-08-11
Two major improvements to the state-of-the-art Repeating Electrostatic Potential Extracted Atomic (REPEAT) method, for generating accurate partial charges for molecular simulations of periodic structures, are here developed. The first, D-REPEAT, consists in the simultaneous fit of the electrostatic potential (ESP), together with the total dipole fluctuations (TDF) of the framework. The second, M-REPEAT, allows the fit of multiple ESP configurations at once. When both techniques are fused into one, DM-REPEAT method, the resulting charges become remarkably stable over a large set of fitting regions, giving a robust and physically sound solution to the buried atoms problem. The method capabilities are extensively studied in ZIF-8 framework, and subsequently applied to IRMOF-1 and ITQ-29 crystal structures. To our knowledge, this is the first time that this approach is proposed in the context of periodic systems.
NASA Astrophysics Data System (ADS)
Faletič, Sergej
2015-05-01
Interviews with students suggest that even though they understand the formalism and the formal nature of quantum theory, they still often desire a mental picture of what the equations describe and some tangible experience with the wavefunctions. Here we discuss a mechanical wave system capable of reproducing correctly a mechanical equivalent of a quantum system in a potential, and the resulting waveforms in principle of any form. We have successfully reproduced the finite potential well, the potential barrier and the parabolic potential. We believe that these mechanical waveforms can provide a valuable experience base for introductory students to start from. We aim to show that mechanical systems that are described with the same mathematics as quantum mechanical, indeed behave in the same way. We believe that even if treated purely as a wave phenomenon, the system provides much insight into wave mechanics. This can be especially useful for physics teachers and others who often need to resort to concepts and experience rather than mathematics when explaining physical phenomena.
ERIC Educational Resources Information Center
Jee-Yon Lee; Hee-Soo Yoo; Jong Sook Park; Kwang-Jin Hwang; Jin Seog Kim
2005-01-01
The spontaneous mixing of helium and air in a helium-inflated balloon is described in an experiment in which the partial pressure of the gases in the balloon are determined from the mole factions and the total pressure measured in the balloon. The results described provide a model for teaching concepts of partial pressure, chemical potential, and…
ERIC Educational Resources Information Center
Jee-Yon Lee; Hee-Soo Yoo; Jong Sook Park; Kwang-Jin Hwang; Jin Seog Kim
2005-01-01
The spontaneous mixing of helium and air in a helium-inflated balloon is described in an experiment in which the partial pressure of the gases in the balloon are determined from the mole factions and the total pressure measured in the balloon. The results described provide a model for teaching concepts of partial pressure, chemical potential, and…
Grosprêtre, Sidney; Martin, Alain
2014-12-01
The aim of this study was to examine the collision responsible for the volitional V-wave evoked by supramaximal electrical stimulation of the motor nerve during voluntary contraction. V-wave was conditioned by transcranial magnetic stimulation (TMS) over the motor cortex at several inter-stimuli intervals (ISI) during weak voluntary plantar flexions (n = 10) and at rest for flexor carpi radialis muscle (FCR; n = 6). Conditioning stimulations were induced by TMS with intensity eliciting maximal motor-evoked potential (MEPmax). ISIs used were ranging from -20 to +20 msec depending on muscles tested. The results showed that, for triceps surae muscles, conditioning TMS increased the V-wave amplitude (~ +250%) and the associated mechanical response (~ +30%) during weak voluntary plantar flexion (10% of the maximal voluntary contraction -MVC) for ISIs ranging from +6 to +18 msec. Similar effect was observed at rest for the FCR with ISI ranging from +6 to +12 msec. When the level of force was increased from 10 to 50% MVC or the conditioning TMS intensity was reduced to elicit responses of 50% of MEPmax, a significant decrease in the conditioned V-wave amplitude was observed for the triceps surae muscles, linearly correlated to the changes in MEP amplitude. The slope of this correlation, as well as the electro-mechanical efficiency, was closed to the identity line, indicating that V-wave impact at muscle level seems to be similar to the impact of cortical stimulation. All these results suggest that change in V-wave amplitude is a great index to reflect changes in cortical neural drive addressed to spinal motoneurons.
Dynamical localization of matter-wave solitons in managed barrier potentials
Abdullaev, Fatkhulla Kh.; Garnier, Josselin
2007-03-15
The bright matter-wave soliton propagation through a barrier with a rapidly oscillating position is investigated. The averaged-over rapid oscillations Gross-Pitaevskii equation is derived, where the effective potential has the form of a finite well. Dynamical trapping and quantum tunneling of the soliton in the effective finite well are investigated. The analytical predictions for the effective soliton dynamics is confirmed by numerical simulations of the full Gross-Pitaevskii equation.
NASA Technical Reports Server (NTRS)
Toncich, S. S.; Collin, R. E.; Bhasin, K. B.
1993-01-01
A technique for a full wave characterization of microstrip open end discontinuities fabricated on uniaxial anisotropic substrates using potential theory is presented. The substrate to be analyzed is enclosed in a cutoff waveguide, with the anisotropic axis aligned perpendicular to the air-dielectric interface. A full description of the sources on the microstrip line is included with edge conditions built in. Extention to other discontinuities is discussed.
Nakashima, Hiroyuki; Nakatsuji, Hiroshi
2013-07-28
We propose here fast antisymmetrization procedures for the partially correlated wave functions that appear in the free complement-local Schrödinger equation (FC-LSE) method. Pre-analysis of the correlation diagram, referred to as dot analysis, combined with the determinant update technique based on the Laplace expansion, drastically reduces the orders of the antisymmetrization computations. When the complement functions include only up to single-correlated terms, the order of computations is O(N(3)), which is the same as the non-correlated case. Similar acceleration is obtained for general correlated functions as a result of dot analysis. This algorithm has been successfully used in our laboratory in actual FC-LSE calculations for accurately solving the many-electron Schrödinger equations of atoms and molecules. The proposed method is general and applicable to the sampling-type methodology of other partially correlated wave functions like those in the quantum Monte Carlo and modern Hylleraas-type methods.
Nakashima, Hiroyuki; Nakatsuji, Hiroshi
2013-07-28
We propose here fast antisymmetrization procedures for the partially correlated wave functions that appear in the free complement-local Schrödinger equation (FC-LSE) method. Pre-analysis of the correlation diagram, referred to as dot analysis, combined with the determinant update technique based on the Laplace expansion, drastically reduces the orders of the antisymmetrization computations. When the complement functions include only up to single-correlated terms, the order of computations is O(N{sup 3}), which is the same as the non-correlated case. Similar acceleration is obtained for general correlated functions as a result of dot analysis. This algorithm has been successfully used in our laboratory in actual FC-LSE calculations for accurately solving the many-electron Schrödinger equations of atoms and molecules. The proposed method is general and applicable to the sampling-type methodology of other partially correlated wave functions like those in the quantum Monte Carlo and modern Hylleraas-type methods.
Deta, U. A.; Suparmi,; Cari,; Husein, A. S.; Yuliani, H.; Khaled, I. K. A.; Luqman, H.; Supriyanto
2014-09-30
The Energy Spectra and Wave Function of Schrodinger equation in D-Dimensions for trigonometric Rosen-Morse potential were investigated analytically using Nikiforov-Uvarov method. This potential captures the essential traits of the quark-gluon dynamics of Quantum Chromodynamics. The approximate energy spectra are given in the close form and the corresponding approximate wave function for arbitrary l-state (l ≠ 0) in D-dimensions are formulated in the form of differential polynomials. The wave function of this potential unnormalizable for general case. The wave function of this potential unnormalizable for general case. The existence of extra dimensions (centrifugal factor) and this potential increase the energy spectra of system.
NASA Astrophysics Data System (ADS)
Brackhagen, O.; Kühn, O.; Manz, J.; May, V.; Meyer, R.
1994-06-01
The dynamics of cyclic systems with four equivalent potential minima is studied here from two different points of view. The solution of the time-dependent Schrödinger equation provides insight into the coherent wave packet motion. The resulting reaction mechanism involves relocalization between opposite, not neighboring potential minima. The inclusion of an environment within a density matrix description leads to dissipation and therefore to a transition from coherent to incoherent dynamics. The theoretical considerations are applied to a simple model of the cyclic motion of a proton in a molecular framework.
Perceptrons with Hebbian Learning Based on Wave Ensembles in Spatially Patterned Potentials
NASA Astrophysics Data System (ADS)
Espinosa-Ortega, T.; Liew, T. C. H.
2015-03-01
A general scheme to realize a perceptron for hardware neural networks is presented, where multiple interconnections are achieved by a superposition of Schrödinger waves. Spatially patterned potentials process information by coupling different points of reciprocal space. The necessary potential shape is obtained from the Hebbian learning rule, either through exact calculation or construction from a superposition of known optical inputs. This allows implementation in a wide range of compact optical systems, including (1) any nonlinear optical system, (2) optical systems patterned by optical lithography, and (3) exciton-polariton systems with phonon or nuclear spin interactions.
NON-WKB MODELS OF THE FIRST IONIZATION POTENTIAL EFFECT: THE ROLE OF SLOW MODE WAVES
Laming, J. Martin
2012-01-10
A model for element abundance fractionation between the solar chromosphere and corona is further developed. The ponderomotive force due to Alfven waves propagating through or reflecting from the chromosphere in solar conditions generally accelerates chromospheric ions, but not neutrals, into the corona. This gives rise to what has become known as the first ionization potential effect. We incorporate new physical processes into the model. The chromospheric ionization balance is improved and the effect of different approximations is discussed. We also treat the parametric generation of slow mode waves by the parallel propagating Alfven waves. This is also an effect of the ponderomotive force, arising from the periodic variation of the magnetic pressure driving an acoustic mode, which adds to the background longitudinal pressure. This can have subtle effects on the fractionation, rendering it quasi-mass independent in the lower regions of the chromosphere. We also briefly discuss the change in the fractionation with Alfven wave frequency, relative to the frequency of the overlying coronal loop resonance.
NASA Astrophysics Data System (ADS)
Acharyya, Aritra; Banerjee, Suranjana; Banerjee, J. P.
2014-03-01
An attempt is made in this paper to explore the potentiality of semiconducting type-IIb diamond as the base material of double-drift region (DDR) impact avalanche transit time (IMPATT) devices operating at both millimetre-wave (mm-wave) and terahertz (THz) frequencies. A rigorous large-signal (L-S) simulation based on the non-sinusoidal voltage excitation (NSVE) model developed earlier by the authors is used in this study. At first, a simulation study based on avalanche response time reveals that the upper cut-off frequency for DDR diamond IMPATTs is 1.5 THz, while the same for conventional DDR Si IMPATTs is much smaller, i.e. 0.5 THz. The L-S simulation results show that the DDR diamond IMPATT device delivers a peak RF power of 7.79 W with an 18.17% conversion efficiency at 94 GHz; while at 1.5 THz, the peak power output and conversion efficiency decrease to 6.19 mW and 8.17% respectively, taking 50% voltage modulation. A comparative study of DDR IMPATTs based on diamond and Si shows that the former excels over the later as regards high frequency and high power performance at both mm-wave and THz frequency bands. The effect of band to band tunneling on the L-S properties of DDR diamond and Si IMPATTs has also been studied at different mm-wave and THz frequencies.
NASA Astrophysics Data System (ADS)
Addassi, Mouadh; Schreyer, Lynn; Johannesson, Björn; Lin, Hai
2016-09-01
Here we illustrate the usefulness of using the chemical potential as the primary unknown by modeling isothermal vapor transport through a partially saturated cylindrically symmetric capillary tube of variable cross-sectional area using a single equation. There are no fitting parameters and the numerical solutions to the equation are compared with experimental results with excellent agreement. We demonstrate that isothermal vapor transport can be accurately modeled without modeling the details of the contact angle, microscale temperature fluctuations, or pressure fluctuations using a modification of the Fick-Jacobs equation. We thus conclude that for a single, axisymmetric pore, the enhancement factor depends upon relative humidity boundary conditions at the liquid bridge interfaces, distance between liquid bridges, and bridge lengths.
Roman-Campos, Danilo; Carneiro-Júnior, Miguel A; Prímola-Gomes, Thales N; Silva, Karina A; Quintão-Júnior, Judson F; Gondim, Antonio Ns; Duarte, Hugo L; Cruz, Jader S; Natali, Antonio J
2012-02-01
Hypertension leads to electrophysiological changes in the heart. Chronic exercise induced by a treadmill-running programme (TRP) is considered a potential non-pharmacological treatment for hypertension and may have implications in heart remodelling. However, it is not known whether the TRP is able to improve the electrophysiological properties of the heart in spontaneously hypertensive rats (SHR). In the present study, we investigated whether TRP affects the electrical properties of left ventricular (LV) myocytes isolated from different layers of the LV wall of SHR. Male SHR were divided into exercised (chronic treadmill running for 8 weeks; CEX-SHR) and sedentary (SED-SHR) groups. Age-matched normotensive Wistar male rats served as controls. Action potentials (AP) and transient outward potassium current (I(to) ) were recorded in subepicardial (EPI) and subendocardial (ENDO) LV myocytes. In normotensive controls, AP duration (APD) was longer in ENDO cells than in EPI cells. This sort of transmural heterogeneity in the LV was not observed in sedentary SHR and was partially restored in SHR subject to chronic exercise. This partial recovery was associated with an increase in I(to) density in EPI cells but not in ENDO cells. The electrophysiological changes observed in the CEX-SHR group were not accompanied by either amelioration of systolic blood pressure or a reduction in heart hypertrophy. These findings imply that a TRP is able to improve the electrophysiological parameters of isolated cardiac myocytes in SHR. This sort of adaptation contributes to the overall improvement of heart physiology in this model. © 2011 The Authors Clinical and Experimental Pharmacology and Physiology © 2011 Blackwell Publishing Asia Pty Ltd.
Adaptive denoising and multiscale detection of the V wave in brainstem auditory evoked potentials.
Popescu, M; Papadimitriou, S; Karamitsos, D; Bezerianos, A
1999-01-01
This paper describes a wavelet-transform-based system for the V wave identification in brainstem auditory evoked potentials (BAEP). The system combines signal denoising and rule-based localization modules. The signal denoising module has the potential of effective noise reduction after signal averaging. It analyses adaptively the evolution of the wavelet transform maxima across scales. The singularities of the signal create wavelet maxima with different properties from those of the induced noise. A non-linear filtering process implemented with a neural network extracts out the noise-induced maxima. The filtered wavelet details are subsequently analysed by the rule-based localization module for the automatic identification of the V wave. In the first phase, it implements a set of statistical observations as well as heuristic criteria used by human experts in order to classify the IV-V complex. At the second phase, using a multiscale focusing algorithm, the IV and V waves are positioned on the BAEP signal. Our experiments revealed that the system provides accurate results even for signals exhibiting unclear IV-V complexes.
Decomposing N2 NOGO wave of event-related potentials into independent components.
Kropotov, Juri D; Ponomarev, Valery A
2009-12-09
Inconsistencies in previous attempts to localize the N2 wave in the GO/NOGO task led to the present investigation. The inconsistencies were probably because of heterogeneity of psychological operations involved in GO/NOGO tasks. We applied the independent component analysis to a collection of individual event-related potentials in response to GO and NOGO cues in the two stimulus visual GO/NOGO task. The selected six independent components with different topographies and time courses constituted 87% of the artifact-free signal variance. Three of them were loaded into the frontally distributed N2 wave. According to standardized low-resolution electromagnetic tomography these three independent components were generated in the supplementary motor cortex, left angular gyrus and anterior cingulate cortex.
Gallet, Basile; Nazarenko, Sergey; Dubrulle, Bérengère
2015-07-01
In field theory, particles are waves or excitations that propagate on the fundamental state. In experiments or cosmological models, one typically wants to compute the out-of-equilibrium evolution of a given initial distribution of such waves. Wave turbulence deals with out-of-equilibrium ensembles of weakly nonlinear waves, and is therefore well suited to address this problem. As an example, we consider the complex Klein-Gordon equation with a Mexican-hat potential. This simple equation displays two kinds of excitations around the fundamental state: massive particles and massless Goldstone bosons. The former are waves with a nonzero frequency for vanishing wave number, whereas the latter obey an acoustic dispersion relation. Using wave-turbulence theory, we derive wave kinetic equations that govern the coupled evolution of the spectra of massive and massless waves. We first consider the thermodynamic solutions to these equations and study the wave condensation transition, which is the classical equivalent of Bose-Einstein condensation. We then focus on nonlocal interactions in wave-number space: we study the decay of an ensemble of massive particles into massless ones. Under rather general conditions, these massless particles accumulate at low wave number. We study the dynamics of waves coexisting with such a strong condensate, and we compute rigorously a nonlocal Kolmogorov-Zakharov solution, where particles are transferred nonlocally to the condensate, while energy cascades towards large wave numbers through local interactions. This nonlocal cascading state constitutes the intermediate asymptotics between the initial distribution of waves and the thermodynamic state reached in the long-time limit.
1985-09-23
6420 5697 26898 0 0 10:18:30 1.06 4420 18019 11092 0 0 10:20:07 1.06 3420 14879 1115 0 0 10:21:4 1.06 2700 5674 0 0 0 10:23:21 1.08 2300 5739 1264 0 0...for Detection and Measurement of Discharge (Corona) Pulses in Evaluation of Insulation Systems," ASTM D1868-73. 5. R. J. Densley, "Partial Discharge...under Direct-Voltage Conditions," Ch. 11 in Engineering Dielectrics, Vol. 1: Corona Measurement and Interpretation, ASTM 669, eds. R. Bartnikas and E. J
Datta, Subimal; O'Malley, Matthew W
2013-03-06
Sleep plays an important role in memory consolidation within multiple memory systems including contextual fear extinction memory, but little is known about the mechanisms that underlie this process. Here, we show that fear extinction training in rats, which extinguished conditioned fear, increased both slow-wave sleep and rapid-eye movement (REM) sleep. Surprisingly, 24 h later, during memory testing, only 57% of the fear-extinguished animals retained fear extinction memory. We found that these animals exhibited an increase in phasic pontine-wave (P-wave) activity during post-training REM sleep, which was absent in the 43% of animals that failed to retain fear extinction memory. The results of this study provide evidence that brainstem activation, specifically potentiation of phasic P-wave activity, during post-training REM sleep is critical for consolidation of fear extinction memory. The results of this study also suggest that, contrary to the popular hypothesis of sleep and memory, increased sleep after training alone does not guarantee consolidation and/or retention of fear extinction memory. Rather, the potentiation of specific sleep-dependent physiological events may be a more accurate predictor for successful consolidation of fear extinction memory. Identification of this unique mechanism will significantly improve our present understanding of the cellular and molecular mechanisms that underlie the sleep-dependent regulation of emotional memory. Additionally, this discovery may also initiate development of a new, more targeted treatment method for clinical disorders of fear and anxiety in humans that is more efficacious than existing methods such as exposure therapy that incorporate only fear extinction.
Fear Extinction Memory Consolidation Requires Potentiation of Pontine-Wave Activity during REM Sleep
Datta, Subimal; O'Malley, Matthew W .
2013-01-01
Sleep plays an important role in memory consolidation within multiple memory systems including contextual fear extinction memory, but little is known about the mechanisms that underlie this process. Here, we show that fear extinction training in rats, which extinguished conditioned fear, increased both slow-wave sleep and rapid-eye movement (REM) sleep. Surprisingly, 24 h later, during memory testing, only 57% of the fear-extinguished animals retained fear extinction memory. We found that these animals exhibited an increase in phasic pontine-wave (P-wave) activity during post-training REM sleep, which was absent in the 43% of animals that failed to retain fear extinction memory. The results of this study provide evidence that brainstem activation, specifically potentiation of phasic P-wave activity, during post-training REM sleep is critical for consolidation of fear extinction memory. The results of this study also suggest that, contrary to the popular hypothesis of sleep and memory, increased sleep after training alone does not guarantee consolidation and/or retention of fear extinction memory. Rather, the potentiation of specific sleep-dependent physiological events may be a more accurate predictor for successful consolidation of fear extinction memory. Identification of this unique mechanism will significantly improve our present understanding of the cellular and molecular mechanisms that underlie the sleep-dependent regulation of emotional memory. Additionally, this discovery may also initiate development of a new, more targeted treatment method for clinical disorders of fear and anxiety in humans that is more efficacious than existing methods such as exposure therapy that incorporate only fear extinction. PMID:23467372
Nigro, Lisa M.; Hyde, Andrew S.; MacGregor, Barbara J.; Teske, Andreas
2016-01-01
Deep-sea hypersaline anoxic basins and other hypersaline environments contain abundant and diverse microbial life that has adapted to these extreme conditions. The bacterial Candidate Division KB1 represents one of several uncultured groups that have been consistently observed in hypersaline microbial diversity studies. Here we report the phylogeography of KB1, its phylogenetic relationships to Candidate Division OP1 Bacteria, and its potential metabolic and osmotic stress adaptations based on a partial single cell amplified genome of KB1 from Orca Basin, the largest hypersaline seafloor brine basin in the Gulf of Mexico. Our results are consistent with the hypothesis – previously developed based on 14C incorporation experiments with mixed-species enrichments from Mediterranean seafloor brines – that KB1 has adapted its proteins to elevated intracellular salinity, but at the same time KB1 apparently imports glycine betaine; this compatible solute is potentially not limited to osmoregulation but could also serve as a carbon and energy source. PMID:27597842
Quantum reflection of bright solitary matter waves from a narrow attractive potential
NASA Astrophysics Data System (ADS)
Marchant, A. L.; Billam, T. P.; Yu, M. M. H.; Rakonjac, A.; Helm, J. L.; Polo, J.; Weiss, C.; Gardiner, S. A.; Cornish, S. L.
2016-02-01
We report the observation of quantum reflection from a narrow attractive potential using bright solitary matter waves formed from a 85Rb Bose-Einstein condensate. We create the attractive potential using a tightly focused, red-detuned laser beam, and observe reflection of up to 25% of the atoms, along with the confinement of atoms at the position of the beam. We show that the observed reflected fraction is much larger than theoretical predictions for a simple Gaussian potential well. A more detailed model of bright soliton propagation, accounting for the generic presence of small subsidiary intensity maxima in the red-detuned beam, suggests that these small intensity maxima are the cause of this enhanced reflection.
Bliokh, K Yu; Bliokh, Yu P
2007-06-01
We present a solution to the problem of partial reflection and refraction of a polarized paraxial Gaussian beam at the interface between two transparent media. The Fedorov-Imbert transverse shifts of the centers of gravity of the reflected and refracted beams are calculated. Our results differ in the general case from those derived previously by other authors. In particular, they obey general conservation law for the beams' total angular momentum but do not obey one-particle conservation laws for individual photons, which have been proposed by [Onoda Phys. Rev. Lett. 93, 083901 (2004)]. We ascertain that these circumstances relate to the artificial model accepted in the literature for the polarized beam; this model does not fit to real beams. The present paper resolves the recent controversy and confirms the results of our previous paper [Bliokh Phys. Rev. Lett. 96, 073903 (2006)]. In addition, a diffraction effect of angular transverse shifts of the reflected and refracted beams is described.
Yang, Yong; Wei, Zhi-tao; Lu, Jin-shan; Zu, Qiang; Wang, Haiyi; Zhang, Xu
2012-06-01
To introduce transurethal partial cystectomy with a 2013 nm thulium laser as a treatment for paraganglioma of the urinary bladder in adults. Three patients with pheochromocytomas were treated transurethrally with a 2013 nm thulium laser under general anesthesia. A 2013 nm thulium laser was used to incise the full-thickness bladder wall around the tumors. The entire bladder wall was peeled between the detrusor muscle layer and outer connective tissues. Tumors with full-thickness detrusor muscle layers at the base were removed together. Intraoperative fluctuation of blood pressure, preoperative values of 24-hour urine catecholamine (CA) and vanillylmandelic acid (VMA), and postoperative complications were observed, and postoperative followtwoups were performed. All operations were successful. Operative time was 25 to 32 minutes. Perioperative blood pressure was stable in two cases while blood pressure fluctuated in the third case. When the entire tumor and the full-thickness bladder wall at the base were freed, blood pressure reverted to stability. All values of 24-hour urine CA and VMA were within normal limits postoperatively. Patients were followed for 7 to 9 months postoperatively with no recurrence. This series included highly selected patients who were treated by a single senior surgeon who is rich in experience in performing 2013 nm thulium laser procedures. To our knowledge, this is the first report of a 2013 nm thulium laser used to treat bladder pheochromocytoma. It can be applied to precisely vaporize and incise the full-thickness bladder wall and cut down the blood supply of the tumor, then peel it while blood pressure remains stable, thus completing partial cystectomy for bladder pheochromocytoma safely.
NASA Astrophysics Data System (ADS)
Murthy, Ganpathy
2000-01-01
It is well known that the ν = 2/5 state is unpolarized at zero Zeeman energy, while it is fully polarized at large Zeeman energies. A novel state with a charge/spin density wave order for composite fermions is proposed to exist at intermediate values of the Zeeman coupling for ν = 2/5. This state has half the maximum possible polarization, and can be extended to other incompressible fractions. A Hartree-Fock calculation based on the new approach for all fractional quantum Hall states developed by R. Shankar and the author is used to demonstrate the stability of this state to single-particle excitations and to compute gaps. A very recent experiment shows direct evidence for this state.
Murthy
2000-01-10
It is well known that the nu = 2/5 state is unpolarized at zero Zeeman energy, while it is fully polarized at large Zeeman energies. A novel state with a charge/spin density wave order for composite fermions is proposed to exist at intermediate values of the Zeeman coupling for nu = 2/5. This state has half the maximum possible polarization, and can be extended to other incompressible fractions. A Hartree-Fock calculation based on the new approach for all fractional quantum Hall states developed by R. Shankar and the author is used to demonstrate the stability of this state to single-particle excitations and to compute gaps. A very recent experiment shows direct evidence for this state.
Bloch-like waves in random-walk potentials based on supersymmetry
Yu, Sunkyu; Piao, Xianji; Hong, Jiho; Park, Namkyoo
2015-01-01
Bloch's theorem was a major milestone that established the principle of bandgaps in crystals. Although it was once believed that bandgaps could form only under conditions of periodicity and long-range correlations for Bloch's theorem, this restriction was disproven by the discoveries of amorphous media and quasicrystals. While network and liquid models have been suggested for the interpretation of Bloch-like waves in disordered media, these approaches based on searching for random networks with bandgaps have failed in the deterministic creation of bandgaps. Here we reveal a deterministic pathway to bandgaps in random-walk potentials by applying the notion of supersymmetry to the wave equation. Inspired by isospectrality, we follow a methodology in contrast to previous methods: we transform order into disorder while preserving bandgaps. Our approach enables the formation of bandgaps in extremely disordered potentials analogous to Brownian motion, and also allows the tuning of correlations while maintaining identical bandgaps, thereby creating a family of potentials with ‘Bloch-like eigenstates'. PMID:26373616
Ghavanini, M R; Ghavanini, A A
1998-12-01
The diagnosis of post-polio syndrome depends not only on clinical signs, but on sophisticated laboratory tests such as histochemical muscle biopsy and immunohistochemical studies which are very expensive and not available in all laboratories. From eighty-eight previous poliomyelitis victims, muscles with grade 4 or lower strength were examined electromyographically for fibrillation potentials and positive sharp waves. There were no muscles with grade III or IV fibrillation potential and positive sharp waves, 8 with grade I (3.7%) and 7 with grade II (3.2%). Fibrillation potentials were more frequent in muscles with lower grade of strength. The minimum time interval between primary insult and the time of evaluation for patients who had sign of denervation was 36 months. This was 28 months for patients who had no sign of denervation. So we can conclude that denervation beyond this time in muscles with power greater than 3/5 is highly suggestive of a new process rather than primary insult in patients with new atrophy or fatigue.
Variety of the Wave Change in Compound Muscle Action Potential in an Animal Model
Ito, Zenya; Ando, Kei; Muramoto, Akio; Kobayashi, Kazuyoshi; Hida, Tetsuro; Ito, Kenyu; Ishikawa, Yoshimoto; Tsushima, Mikito; Matsumoto, Akiyuki; Tanaka, Satoshi; Morozumi, Masayoshi; Matsuyama, Yukihiro; Ishiguro, Naoki
2015-01-01
Study Design Animal study. Purpose To review the present warning point criteria of the compound muscle action potential (CMAP) and investigate new criteria for spinal surgery safety using an animal model. Overview of Literature Little is known about correlation palesis and amplitude of spinal cord monitoring. Methods After laminectomy of the tenth thoracic spinal lamina, 2-140 g force was delivered to the spinal cord with a tension gage to create a bilateral contusion injury. The study morphology change of the CMAP wave and locomotor scale were evaluated for one month. Results Four different types of wave morphology changes were observed: no change, amplitude decrease only, morphology change only, and amplitude and morphology change. Amplitude and morphology changed simultaneously and significantly as the injury force increased (p<0.05) Locomotor scale in the amplitude and morphology group worsened more than the other groups. Conclusions Amplitude and morphology change of the CMAP wave exists and could be the key of the alarm point in CMAP. PMID:26713129
Chen, Jun; Yang, Jin; Li, Zhaoling; Fan, Xing; Zi, Yunlong; Jing, Qingshen; Guo, Hengyu; Wen, Zhen; Pradel, Ken C; Niu, Simiao; Wang, Zhong Lin
2015-03-24
With 70% of the earth's surface covered with water, wave energy is abundant and has the potential to be one of the most environmentally benign forms of electric energy. However, owing to lack of effective technology, water wave energy harvesting is almost unexplored as an energy source. Here, we report a network design made of triboelectric nanogenerators (TENGs) for large-scale harvesting of kinetic water energy. Relying on surface charging effect between the conventional polymers and very thin layer of metal as electrodes for each TENG, the TENG networks (TENG-NW) that naturally float on the water surface convert the slow, random, and high-force oscillatory wave energy into electricity. On the basis of the measured output of a single TENG, the TENG-NW is expected to give an average power output of 1.15 MW from 1 km(2) surface area. Given the compelling features, such as being lightweight, extremely cost-effective, environmentally friendly, easily implemented, and capable of floating on the water surface, the TENG-NW renders an innovative and effective approach toward large-scale blue energy harvesting from the ocean.
Tunnelling time of a gaussian wave packet through two potential barriers
NASA Astrophysics Data System (ADS)
Petrillo, Vittoria; Olkhovsky, Vladislav
2005-09-01
The resonant and non-resonant dynamies of a Gaussian quantum wave packet travelling through a double barrier system is studied as a function of the initial characteristics of the spectrum and of the parameters of the potential. The behaviour of the tunnelling time shows that there are situations where the Hartman effect occurs, while, when the resonances are dominant, and in particular for b>π/Δk (b being the inter-barrier distance and Δk the spectrum width), the tunnelling time becomes very large and the Hartman effect does not take place.
Potential-vorticity inversion and the wave-turbulence jigsaw: some recent clarifications
NASA Astrophysics Data System (ADS)
McIntyre, M. E.
2008-06-01
Two key ideas stand out as crucial to understanding atmosphere-ocean dynamics, and the dynamics of other planets including the gas giants. The first key idea is the invertibility principle for potential vorticity (PV). Without it, one can hardly give a coherent account of even so important and elementary a process as Rossby-wave propagation, going beyond the simplest textbook cases. Still less can one fully understand nonlinear processes like the self-sharpening or narrowing of jets the once-mysterious "negative viscosity" phenomenon. The second key idea, also crucial to understanding jets, might be summarized in the phrase "there is no such thing as turbulence without waves", meaning Rossby waves especially. Without this idea one cannot begin to make sense of, for instance, momentum budgets and eddy momentum transports in complex large-scale flows. Like the invertibility principle the idea has long been recognized, or at least adumbrated. However, it is worth articulating explicitly if only because it can be forgotten when, in the usual way, we speak of "turbulence" and "turbulence theory" as if they were autonomous concepts. In many cases of interest, such as the well-studied terrestrial stratosphere, reality is more accurately described as a highly inhomogeneous "wave-turbulence jigsaw puzzle" in which wavelike and turbulent regions fit together and crucially affect each other's evolution. This modifies, for instance, formulae for the Rhines scale interpreted as indicating the comparable importance of wavelike and turbulent dynamics. Also, weakly inhomogeneous turbulence theory is altogether inapplicable. For instance there is no scale separation. Eddy scales are not much smaller than the sizes of the individual turbulent regions in the jigsaw. Here I review some recent progress in clarifying these ideas and their implications.
Balderson, Michael John; Kirkby, Charles
2014-02-01
This work investigated the potential implications on tumour control probability (TCP) for external beam prostate cancer treatment when considering the bystander effect in partial exposure scenarios. The biological response of a prostate cancer target volume under conditions where a sub-volume of the target volume was not directly irradiated was modelled in terms of surviving fraction (SF) and Poisson-based TCP. A direct comparison was made between the linear-quadratic (LQ) response model, and a response model that incorporates bystander effects as derived from published in vitro data by McMahon et al. in 2012 and 2013. Scenarios of random and systematic misses were considered. Our results suggested the potential for the bystander effect to deviate from LQ predictions when even very small (< 1%) sub-volumes of the target volume were directly irradiated. Under conditions of random misses for each fraction, the bystander model predicts a 3% and 1% improvement in tumour control compared to that predicted by an LQ model when only 90% and 95% of the prostate cells randomly receive the intended dose. Under conditions of systematic miss, if even a small portion of the target volume is not directly exposed, the LQ model predicts a TCP approaching zero, whereas the bystander model suggests TCP will improve starting at exposed volumes of around 85%. The bystander model, when applied to clinically relevant scenarios, demonstrates the potential to deviate from the TCP predictions of the common local LQ model when sub-volumes of a target volume are randomly or systematically missed over a course of fractionated radiation therapy.
Mumoli, Laura; Palleria, Caterina; Gasparini, Sara; Citraro, Rita; Labate, Angelo; Ferlazzo, Edoardo; Gambardella, Antonio; De Sarro, Giovambattista; Russo, Emilio
2015-01-01
Brivaracetam (BRV), a high-affinity synaptic vesicle protein 2A ligand, reported to be 10–30-fold more potent than levetiracetam (LEV), is highly effective in a wide range of experimental models of focal and generalized seizures. BRV and LEV similarly bind to synaptic vesicle protein 2A, while differentiating for other pharmacological effects; in fact, BRV does not inhibit high voltage Ca2+ channels and AMPA receptors as LEV. Furthermore, BRV apparently exhibits inhibitory activity on neuronal voltage-gated sodium channels playing a role as a partial antagonist. BRV is currently waiting for approval both in the United States and the European Union as adjunctive therapy for patients with partial seizures. In patients with photosensitive epilepsy, BRV showed a dose-dependent effect in suppressing or attenuating the photoparoxysmal response. In well-controlled trials conducted to date, adjunctive BRV demonstrated efficacy and good tolerability in patients with focal epilepsy. BRV has a linear pharmacokinetic profile. BRV is extensively metabolized and excreted by urine (only 8%–11% unchanged). The metabolites of BRV are inactive, and hydrolysis of the acetamide group is the mainly involved metabolic pathway; hepatic impairment probably requires dose adjustment. BRV does not seem to influence other antiepileptic drug plasma levels. Six clinical trials have so far been completed indicating that BRV is effective in controlling seizures when used at doses between 50 and 200 mg/d. The drug is generally well-tolerated with only mild-to-moderate side effects; this is confirmed by the low discontinuation rate observed in these clinical studies. The most common side effects are related to central nervous system and include fatigue, dizziness, and somnolence; these apparently disappear during treatment. In this review, we analyzed BRV, focusing on the current evidences from experimental animal models to clinical studies with particular interest on potential use in clinical
Banerjee, Gadadhar Maitra, Sarit
2016-06-21
Sagdeev pseudopotential method is employed to study the arbitrary amplitude quantum ion-acoustic solitary waves in an unmagnetized electron-positron-ion plasma by using one dimensional quantum hydrodynamic model together with the Poisson equation. Sagdeev potential function is obtained in terms of electrostatic potential and analyzed with and without the effect of quantum diffraction parameter H. Effects of the parameter H on both the amplitude and width of the solitary waves have been observed. It is also observed that the positron density can affect the wave propagation.
Bliokh, K. Yu.; Bliokh, Yu. P.
2007-06-15
We present a solution to the problem of partial reflection and refraction of a polarized paraxial Gaussian beam at the interface between two transparent media. The Fedorov-Imbert transverse shifts of the centers of gravity of the reflected and refracted beams are calculated. Our results differ in the general case from those derived previously by other authors. In particular, they obey general conservation law for the beams' total angular momentum but do not obey one-particle conservation laws for individual photons, which have been proposed by [Onoda et al. Phys. Rev. Lett. 93, 083901 (2004)]. We ascertain that these circumstances relate to the artificial model accepted in the literature for the polarized beam; this model does not fit to real beams. The present paper resolves the recent controversy and confirms the results of our previous paper [Bliokh et al. Phys. Rev. Lett. 96, 073903 (2006)]. In addition, a diffraction effect of angular transverse shifts of the reflected and refracted beams is described.
Potential Impacts of Hydrokinetic and Wave Energy Conversion Technologies on Aquatic Environments
Čada, Glenn F.
2007-04-01
A new generation of hydropower technologies, the kinetic hydro and wave energy conversion devices, offers the possibility of generating electricity from the movements of water, without the need for dams and diversions. The Energy Policy Act of 2005 encouraged the development of these sources of renewable energy in the United States, and there is growing interest in deploying them globally. The technologies that would extract electricity from free-flowing streams, estuaries, and oceans have not been widely tested. Consequently, the U.S. Department of Energy convened a workshop to (1) identify the varieties of hydrokinetic energy and wave energy conversion devices and their stages of development, (2) identify where these technologies can best operate, (3) identify the potential environmental issues associated with these technologies and possible mitigation measures, and (4) develop a list of research needs and/or practical solutions to address unresolved environmental issues. The article reviews the results of that workshop, focusing on potential effects on freshwater, estuarine, and marine ecosystems, and we describe recent national and international developments.
NASA Astrophysics Data System (ADS)
Mizuno, M.; Hirata, A.; Kawase, K.; Otani, C.; Nagatsuma, T.
2004-08-01
Non-thermal effects of millimeter wave (MMW) on Pheochromocytoma (PC12) were studied by potential measurement with a voltage sensitive dye (DiBAC4(3)). Cells were irradiated at fixed frequencies of 30, 40, 60, 76GHz as well as sweeping frequency between 10 and 100 GHz by an MMW generator based on a uni-traveling-carrier photodiode (UTC-PD), the most widely tunable MMW source. However there were no significant changes in membrane potential between MMW-irradiated and control cells. The results suggest that MMW irradiation in the range from 10 to 100GHz appears to be safe for ordinary PC12 cells under non-thermal conditions.
Nonlinear wave dynamics near phase transition in PT-symmetric localized potentials
NASA Astrophysics Data System (ADS)
Nixon, Sean; Yang, Jianke
2016-09-01
Nonlinear wave propagation in parity-time symmetric localized potentials is investigated analytically near a phase-transition point where a pair of real eigenvalues of the potential coalesce and bifurcate into the complex plane. Necessary conditions for a phase transition to occur are derived based on a generalization of the Krein signature. Using the multi-scale perturbation analysis, a reduced nonlinear ordinary differential equation (ODE) is derived for the amplitude of localized solutions near phase transition. Above the phase transition, this ODE predicts a family of stable solitons not bifurcating from linear (infinitesimal) modes under a certain sign of nonlinearity. In addition, it predicts periodically-oscillating nonlinear modes away from solitons. Under the opposite sign of nonlinearity, it predicts unbounded growth of solutions. Below the phase transition, solution dynamics is predicted as well. All analytical results are compared to direct computations of the full system and good agreement is observed.
Interacting particles in a periodically moving potential: traveling wave and transport.
Chatterjee, Rakesh; Chatterjee, Sakuntala; Pradhan, Punyabrata; Manna, S S
2014-02-01
We study a system of interacting particles in a periodically moving external potential, within the simplest possible description of paradigmatic symmetric exclusion process on a ring. The model describes diffusion of hardcore particles where the diffusion dynamics is locally modified at a uniformly moving defect site, mimicking the effect of the periodically moving external potential. The model, though simple, exhibits remarkably rich features in particle transport, such as polarity reversal and double peaks in particle current upon variation of defect velocity and particle density. By tuning these variables, the most efficient transport can be achieved in either direction along the ring. These features can be understood in terms of a traveling density wave propagating in the system. Our results could be experimentally tested, e.g., in a system of colloidal particles driven by a moving optical tweezer.
Gabarró, J; Hernández-Del Amo, E; Gich, F; Ruscalleda, M; Balaguer, M D; Colprim, J
2013-12-01
This study investigates the microbial community dynamics in an intermittently aerated partial nitritation (PN) SBR treating landfill leachate, with emphasis to the nosZ encoding gene. PN was successfully achieved and high effluent stability and suitability for a later anammox reactor was ensured. Anoxic feedings allowed denitrifying activity in the reactor. The influent composition influenced the mixed liquor suspended solids concentration leading to variations of specific operational rates. The bacterial community was low diverse due to the stringent conditions in the reactor, and was mostly enriched by members of Betaproteobacteria and Bacteroidetes as determined by 16S rRNA sequencing from excised DGGE melting types. The qPCR analysis for nitrogen cycle-related enzymes (amoA, nirS, nirK and nosZ) demonstrated high amoA enrichment but being nirS the most relatively abundant gene. nosZ was also enriched from the seed sludge. Linear correlation was found mostly between nirS and the organic specific rates. Finally, Bacteroidetes sequenced in this study by 16S rRNA DGGE were not sequenced for nosZ DGGE, indicating that not all denitrifiers deal with complete denitrification. However, nosZ encoding gene bacteria was found during the whole experiment indicating the genetic potential to reduce N2O.
Jetiyanon, Kanchalee; Plianbangchang, Pinyupa
2012-03-30
There is increasing interest in the development of technologies which can reduce the requirement for chemical fertilisers in rice production. The objective of this study was to investigate the efficacy of Bacillus cereus strain RS87 for the partial replacement of chemical fertiliser in rice production. A greenhouse experiment was designed using different fertiliser regimes, with and without strain RS87. Six Thai rice cultivars were tested separately. Maximum rice growth and yield were obtained in rice receiving the full recommended fertiliser rate in combination with the strain RS87. Interestingly, all rice cultivars which were treated with strain RS87 and 50% recommended fertiliser rate provided equivalent plant growth and yield to that receiving the full recommended fertiliser rate only. A paired comparison between rice treated with 50% of the recommended fertiliser rate with the bacterial inoculant and the full fertiliser rate alone was further examined in small experimental rice paddy fields. Growth and yield of all rice cultivars which received the 50% fertiliser rate supplemented with strain RS87 gave a similar yield to that receiving the full fertiliser rate alone. Bacterial strain RS87 showed the potential to replace 50% of the recommended fertiliser rate for yield production. Integration of plant growth-promoting rhizobacterial inoculants with reduced application rates of chemical fertiliser appears promising for future agriculture. Copyright © 2012 Society of Chemical Industry.
A Double-Partial Least-Squares Model for the Detection of Steady-State Visual Evoked Potentials.
Ge, Sheng; Wang, Ruimin; Leng, Yue; Wang, Haixian; Lin, Pan; Iramina, Keiji
2017-07-01
Establishing a high-accuracy and training-free brain-computer interface (BCI) system is essential for improving BCI practicality. In this study, we propose for the first time a training-free double-partial least-squares (D-PLS) model for steady-state visual evoked potential (SSVEP) detection that consists of double-layer PLS, a PLS spatial filter, and a PLS feature extractor. Electroencephalographic data from 11 healthy volunteers under four different visual stimulation frequencies were used to test the proposed method. Compared with commonly used spatial filters, minimum energy combination and average maximum contrast combination, the classification accuracies could be improved 2-10% by our proposed PLS spatial filter. Furthermore, our proposed PLS feature extractor achieved better performance than current feature extraction methods, namely power spectral density analysis, canonical correlation analysis, and the use of the least absolute shrinkage and selection operator. The average classification accuracy for our proposed D-PLS model exceeded [Formula: see text] when the signal time window was longer than 3.5 s and reached as high as [Formula: see text] when the time window was 5 s. Moreover, the D-PLS model can be easily set without training data, so it can be used widely in SSVEP-based BCI systems.
NASA Astrophysics Data System (ADS)
Xu, Zongbo; Xia, Jianghai; Luo, Yinhe; Cheng, Feng; Pan, Yudi
2016-04-01
People have calculated Rayleigh-wave phase velocities from vertical component of ambient seismic noise for several years. Recently, researchers started to extract Love waves from transverse component recordings of ambient noise, where "transverse" is defined as the direction perpendicular to a great-circle path or a line in small scale through observation sensors. Most researches assumed Rayleigh waves could be negligible, but Rayleigh waves can exist in the transverse component when Rayleigh waves propagate in other directions besides radial direction. In study of data acquired in western Junggar Basin near Karamay city, China, after processing the transverse component recordings of ambient noise, we obtain two energy trends, which are distinguished with Rayleigh-wave and Love-wave phase velocities, in the frequency-velocity domain using multichannel analysis of surface waves (MASW). Rayleigh waves could be also extracted from the transverse component data. Because Rayleigh-wave and Love-wave phase velocities are close in high frequencies (>0.1 Hz), two kinds of surface waves might be merged in the frequency-velocity domain. Rayleigh-wave phase velocities may be misidentified as Love-wave phase velocities. To get accurate surface-wave phase velocities from the transverse component data using seismic interferometry in investigating the shallow geology, our results suggest using MASW to calculate real Love-wave phase velocities.
Fachruddin, Imam Salam, Agus
2016-03-11
A new momentum-space formulation for scattering of two spin-half particles, both either identical or unidentical, is formulated. As basis states the free linear-momentum states are not expanded into the angular-momentum states, the system’s spin states are described by the product of the spin states of the two particles, and the system’s isospin states by the total isospin states of the two particles. We evaluate the Lippmann-Schwinger equations for the T-matrix elements in these basis states. The azimuthal behavior of the potential and of the T-matrix elements leads to a set of coupled integral equations for the T-matrix elements in two variables only, which are the magnitude of the relative momentum and the scattering angle. Some symmetry relations for the potential and the T-matrix elements reduce the number of the integral equations to be solved. A set of six spin operators to express any interaction of two spin-half particles is introduced. We show the spin-averaged differential cross section as being calculated in terms of the solution of the set of the integral equations.
Potential health effects of standing waves generated by low frequency noise.
Ziaran, Stanislav
2013-01-01
The main aim is to present the available updated knowledge regarding the potential health effects of standing waves generated by low frequency noise (LFN) from an open window in a moving car where the negative effects of LFN induced by heating components and/or heating, ventilation and air-conditioning are assessed. Furthermore, the assessment of noise in chosen enclosed spaces, such as rooms, offices, and classrooms, or other LFN sources and their effect on the human being were investigated. These types of noise are responsible for disturbance during relaxation, sleep, mental work, education, and concentration, which may reflect negatively on the comfort and health of the population and on the mental state of people such as scientific staff and students. The assessment points out the most exposed areas, and analyzes the conditions of standing wave generation in these rooms caused by outdoor and/or indoor sources. Measurements were made for three different enclosed spaces (office, flat, and passenger car) and sources (traffic specific noise at intersections, noise induced by pipe vibration, and aerodynamic noise) and their operating conditions. For the detection of LFN, the A-weighted sound pressure level and vibration were measured and a fast Fourier transform analysis was used. The LFN sources are specified and the direct effects on the human are reported. Finally, this paper suggests the possibilities for the assessment of LFN and some possible measures that can be taken to prevent or reduce them.
Effect of Bohm quantum potential in the propagation of ion-acoustic waves in degenerate plasmas
NASA Astrophysics Data System (ADS)
Hasan, M. M.; Hossen, M. A.; Rafat, A.; Mamun, A. A.
2016-10-01
A theoretical investigation has been carried out on the propagation of the ion-acoustic (IA) waves in a relativistic degenerate plasma containing relativistic degenerate electron and positron fluids in the presence of inertial non-relativistic light ion fluid. The Korteweg-de Vries (K-dV), modified K-dV (mK-dV), and mixed mK-dV (mmK-dV) equations are derived by adopting the reductive perturbation method. In order to analyze the basic features (phase speed, amplitude, width, etc.) of the IA solitary waves (SWs), the SWs solutions of the K-dV, mK-dV, and mmK-dV are numerically analyzed. It is found that the degenerate pressure, inclusion of the new phenomena like the Fermi temperatures and quantum mechanical effects (arising due to the quantum diffraction) of both electrons and positrons, number densities, etc., of the plasma species remarkably change the basic characteristics of the IA SWs which are found to be formed either with positive or negative potential. The implication of our results in explaining different nonlinear phenomena in astrophysical compact objects, e.g., white dwarfs, neutron stars, etc., and laboratory plasmas like intense laser-solid matter interaction experiments, etc., are mentioned.
Colosimo, Alessia; Russo, Valentina; Mauro, Annunziata; Curini, Valentina; Marchisio, Marco; Bernabò, Nicola; Alfonsi, Melissa; Mattioli, Mauro; Barboni, Barbara
2013-08-01
Ovine amniotic fluid mesenchymal stromal cells (oAFMSCs) are an emerging alternative source of stem cells to develop pre-clinical cell replacement protocols. For tissue engineering purposes, oAFMSCs can be used either immediately after isolation or after in vitro expansion. However, detailed studies are still required to investigate the advantages and drawbacks of their in vitro expansion. The phenotype and osteogenic differentiation potential of oAFMSCs were analyzed in relation to in vitro expansion that was carried out for 20 consecutive passages. Expanded oAFMSCs were analyzed for proliferation index, expression profiles of several surface, pluripotency-associated and HLA antigens, global DNA methylation, telomere length and karyotype. The osteogenic differentiation ability of expanded oAFMSCs was assessed by qualitative and quantitative methods. Expanded oAFMSCs reduced their proliferative activity after 10 passages and partially modified the expression of surface antigens and the intracellular distribution of pluripotency-associated markers (NANOG, SOX2 and TERT) after 20 passages. The phenotypic alteration of cultured oAFMSCs was associated with a reduction of in vitro osteogenic plasticity. In detail, after 20 passages of cellular expansion, oAFMSCs lost the ability to increase osteocalcin and decreased collagen type I messenger RNA expression. Also, a lower percentage of cells displayed intracellular calcium release after stimulation with salmon calcitonin. The results presented here suggest that long-term in vitro expansion may cause significant alterations in phenotypic features and plasticity of oAFMSCs, suggesting a careful re-evaluation of in vitro cultural and temporal conditions before employing expanded oAFMSCs for therapeutic purposes. Copyright © 2013 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.
Colrain, Ian M; Padilla, Mayra L; Baker, Fiona C
2012-01-01
Stimuli presented during sleep can produce an evoked EEG delta wave referred to as a K-complex. These responses occur when large numbers of cortical cells burst fire in a synchronized manner. Large amplitude synchronized scalp responses require that the CNS contain large numbers of healthy neurons that are interconnected with highly functional white matter pathways. The P2, N550, and P900 components of the evoked K-complex are sensitive measures of normal healthy brain aging, showing a decrease in amplitude with age. N550 and P900 amplitudes are also reduced in recently detoxified alcoholics, most dramatically over frontal scalp regions. The present study tested the hypothesis that the amplitude of K-complex related evoked potential components would increase with prolonged abstinence. Fifteen alcoholics (12 men) were studied twice, separated by a 12 month period, during which time they were followed with monthly phone calls. Subjects were aged between 38 and 60 years at their first study. They had on average a 29.3 ± 6.7 year drinking history and had been abstinent for between 54 and 405 days at initial testing. Evoked K-complexes were identified in the EEG and averaged to enable measurement of the P2, N550 and P900 peaks. Data were collected from seven scalp sites (FP1, FP2, Fz, FCz, Cz, CPz, and Pz). N550 and P900 amplitudes were significantly higher after 12 months of abstinence and an improvement of at least 5 μV occurred in 12 of the 15 subjects. N550 and P900 also showed highly significant site by night interactions with the largest increases occurring over prefrontal and frontal sites. The data indicate that the sleep evoked response may provide a sensitive marker of brain recovery with abstinence from alcohol.
NASA Astrophysics Data System (ADS)
Abboud, Toufic; Joly, Patrick; Rodríguez, Jerónimo; Terrasse, Isabelle
2011-07-01
This work deals with the numerical simulation of wave propagation on unbounded domains with localized heterogeneities. To do so, we propose to combine a discretization based on a discontinuous Galerkin method in space and explicit finite differences in time on the regions containing heterogeneities with the retarded potential method to account the unbounded nature of the computational domain. The coupling formula enforces a discrete energy identity ensuring the stability under the usual CFL condition in the interior. Moreover, the scheme allows to use a smaller time step in the interior domain yielding to quasi-optimal discretization parameters for both methods. The aliasing phenomena introduced by the local time stepping are reduced by a post-processing by averaging in time obtaining a stable and second order consistent (in time) coupling algorithm. We compute the numerical rate of convergence of the method for an academic problem. The numerical results show the feasibility of the whole discretization procedure.
Form factors and the s-wave component of the two-pion-exchange three-nucleon potential
Robilotta, M.R.; Isidro Filho, M.P.; Coelho, H.T.; Das, T.K.
1985-02-01
We argue that the straightforward introduction of ..pi..N form factors into the s-wave component of the two-pion-exchange three-nucleon potential based on chiral symmetry is not free of problems. These can be avoided by means of a redefinition of the potential which considers its physical content.
NASA Astrophysics Data System (ADS)
Yasuda, Seiji; Miura, Hitoshi; Nakamoto, Taishi
2009-11-01
We carried out three-dimensional hydrodynamics simulations of the disruption of a partially-molten dust particle exposed to high-speed gas flow to examine the compound chondrule formation due to mutual collisions between the fragments (fragment-collision model; [Miura, H., Yasuda, S., Nakamoto, T., 2008a. Icarus194, 811-821]). In the shock-wave heating model, which is one of the most plausible models for chondrule formation, the gas friction heats and melts the surface of the cm-sized dust particle (parent particle) and then the strong gas ram pressure causes the disruption of the molten surface layer. The hydrodynamics simulation shows details of the disruptive motion of the molten surface, production of many fragments and their trajectories parting from the parent particle, and mutual collisions among them. In our simulation, we identified 32 isolated fragments extracted from the parent particle. The size distribution of the fragments was similar to that obtained from the aerodynamic experiment in which a liquid layer was attached to a solid core and it was exposed to a gas flow. We detected 12 collisions between the fragments, which may result in the compound chondrule formation. We also analyzed the paths of all the fragments in detail and found the importance of the shadow effect in which a fragment extracted later blocks the gas flow toward a fragment extracted earlier. We examined the collision velocity and impact parameter of each collision and found that 11 collisions should result in coalescence. It means that the ratio of coalescent bodies to single bodies formed in this disruption of a parent particle is R=11/(32-11)=0.52. We concluded that compound chondrule formation can occur just after the disruption of a cm-sized molten dust particle in shock-wave heating.
NASA Astrophysics Data System (ADS)
Williams, Mike
This work presents measurements of differential cross sections, dsigma/dcos qwCM , and spin density matrix elements, r0MM' , for the reaction gammap → po in the energy range 1.72 GeV< s <2.84 GeV. The data were collected at Jefferson Lab, using the CLAS detector, as part of the g11a run period in 2004. Our r0MM' measurements vastly increase the precision of the world's data and extend the large angle measurements by over 400 MeV in s . Our data confirms that for s < 2.1 GeV, the forward angle (small |t|) production amplitude is dominated by t-channel pi0 exchange. At higher energies, existing non-resonant models do a poor job of describing our data. In particular, u-channel models fail to reproduce our highest energy backwards r0MM' measurements. A mass-independent partial wave analysis has also been performed. Near threshold, the dominant resonance contributions extracted are the **** F15 (1680) and *** D 13(1700). Together with the t-channel pi0 exchange, these three waves provide a remarkably good description of our differential cross section and spin density matrix element measurements for s < 2 GeV. Strong, but not conclusive, evidence for the **** G17(2190) has also been extracted. Improved non-resonant models may be necessary to irrefutably show whether this state contributes to o photoproduction. Evidence for missing resonances is suggestive, but inconclusive without theoretical input.
Reconstruction of multiple gastric electrical wave fronts using potential based inverse methods
Kim, J HK; Pullan, A J; Cheng, L K
2012-01-01
One approach, commonly used in the field of electrocardiography, involves solving an inverse problem whereby electrical potentials on the stomach surface are directly reconstructed from dense potential measurements on the skin surface. To investigate this problem, an anatomically realistic torso model and an electrical stomach model were used to simulate potentials on stomach and skin surfaces arising from normal gastric electrical activity. The effectiveness of the Greensite-Tikhonov or the Tikhonov inverse methods were compared under the presence of 10% Gaussian noise with either 84 or 204 body surface electrodes. The stability and accuracy of the Greensite-Tikhonov method was further investigated by introducing varying levels of Gaussian signal noise or by increasing or decreasing the size of the stomach by 10%. Results showed that the reconstructed solutions were able to represent the presence of propagating multiple wave fronts and the Greensite-Tikhonov method with 204 electrodes performed best (Correlation coefficients of activation time: 90%; Pacemaker localization error: 3 cm). The Greensite-Tikhonov method was stable with Gaussian noise levels up to 20% and 10% change in stomach size. The use of 204 rather than 84 body surface electrodes improved the performance; however, for all investigated cases, the Greensite-Tikhonov method outperformed the Tikhonov method. PMID:22842812
Reconstruction of multiple gastric electrical wave fronts using potential-based inverse methods.
Kim, J H K; Pullan, A J; Cheng, L K
2012-08-21
One approach for non-invasively characterizing gastric electrical activity, commonly used in the field of electrocardiography, involves solving an inverse problem whereby electrical potentials on the stomach surface are directly reconstructed from dense potential measurements on the skin surface. To investigate this problem, an anatomically realistic torso model and an electrical stomach model were used to simulate potentials on stomach and skin surfaces arising from normal gastric electrical activity. The effectiveness of the Greensite-Tikhonov or the Tikhonov inverse methods were compared under the presence of 10% Gaussian noise with either 84 or 204 body surface electrodes. The stability and accuracy of the Greensite-Tikhonov method were further investigated by introducing varying levels of Gaussian signal noise or by increasing or decreasing the size of the stomach by 10%. Results showed that the reconstructed solutions were able to represent the presence of propagating multiple wave fronts and the Greensite-Tikhonov method with 204 electrodes performed best (correlation coefficients of activation time: 90%; pacemaker localization error: 3 cm). The Greensite-Tikhonov method was stable with Gaussian noise levels up to 20% and 10% change in stomach size. The use of 204 rather than 84 body surface electrodes improved the performance; however, for all investigated cases, the Greensite-Tikhonov method outperformed the Tikhonov method.
Reconstruction of multiple gastric electrical wave fronts using potential-based inverse methods
NASA Astrophysics Data System (ADS)
Kim, J. H. K.; Pullan, A. J.; Cheng, L. K.
2012-08-01
One approach for non-invasively characterizing gastric electrical activity, commonly used in the field of electrocardiography, involves solving an inverse problem whereby electrical potentials on the stomach surface are directly reconstructed from dense potential measurements on the skin surface. To investigate this problem, an anatomically realistic torso model and an electrical stomach model were used to simulate potentials on stomach and skin surfaces arising from normal gastric electrical activity. The effectiveness of the Greensite-Tikhonov or the Tikhonov inverse methods were compared under the presence of 10% Gaussian noise with either 84 or 204 body surface electrodes. The stability and accuracy of the Greensite-Tikhonov method were further investigated by introducing varying levels of Gaussian signal noise or by increasing or decreasing the size of the stomach by 10%. Results showed that the reconstructed solutions were able to represent the presence of propagating multiple wave fronts and the Greensite-Tikhonov method with 204 electrodes performed best (correlation coefficients of activation time: 90%; pacemaker localization error: 3 cm). The Greensite-Tikhonov method was stable with Gaussian noise levels up to 20% and 10% change in stomach size. The use of 204 rather than 84 body surface electrodes improved the performance; however, for all investigated cases, the Greensite-Tikhonov method outperformed the Tikhonov method.
Current status of a coupled-channel partial wave analysis using data from CLAS at Jefferson Lab
M. Bellis, Z. Krahn, M. McCracken, C. Meyer and M. Williams
2009-04-01
The non-strange baryon spectrum has been mapped out predominantly by studying N π elastic scattering with phase-shift analysis as the tool of choice. While there has been much success with these experimental techniques, the results have fueled debates in the community, most notably regarding the missing baryons problem. Theoretical solutions to this discrepancy appeal to a diquark-system within the baryons or a coupling to states other than N π. The CLAS detector at Jefferson Lab has turned out high-statistics, photoproduction datasets which are optimal for resolving these issues. However, new analytical techniques may be required to deal with this rich physics sector. The baryon resonances are photoproduced off liquid hydrogen and the CLAS detector allows us to measure a variety of final states. We will have access to nπ +, pπ 0, pπ + π −, pω,pη, pη′, ΛK + and ΣK + final states. A robust software package has been developed that allows for the fitting of these states individually and in a coupled-channel mode. We make use of flexible C++ based tools that allow fast and general calculations of amplitudes based on a covariant tensor formalism. New techniques have been applied to background subtraction which brings an added level of consistency to the analysis. Polarization information from other experiments is incorporated at fit time to help distinguish potentially ambiguous physics processes by using information outside of the CLAS datasets. Some of these channels have more mature analysis (pω,ΛK +) and the preliminary measuremen will be shown as well as an overview of the analysis tools.
Thomas L. Eberhardt; Stan Lebow; Karen G. Reed
2012-01-01
A cellulose solvent system based on lithium chloride (LiCl) in N-methyl-2-pyrrolidinone (NMP) was used to assess the merits of partial dissolutions of coarsely ground wood samples. Alkaline Copper Quaternary (ACQ)-treated pine wood was of particular interest for treatment given the potential to generate a copper- rich stream apart from solid and/or liquid...
He Junrong; Li Huamei
2011-06-15
A large family of analytical solitary wave solutions to the generalized nonautonomous cubic-quintic nonlinear Schroedinger equation with time- and space-dependent distributed coefficients and external potentials are obtained by using a similarity transformation technique. We use the cubic nonlinearity as an independent parameter function, where a simple procedure is established to obtain different classes of potentials and solutions. The solutions exist under certain conditions and impose constraints on the coefficients depicting dispersion, cubic and quintic nonlinearities, and gain (or loss). We investigate the space-quadratic potential, optical lattice potential, flying bird potential, and potential barrier (well). Some interesting periodic solitary wave solutions corresponding to these potentials are then studied. Also, properties of a few solutions and physical applications of interest to the field are discussed. Finally, the stability of the solitary wave solutions under slight disturbance of the constraint conditions and initial perturbation of white noise is discussed numerically; the results reveal that the solitary waves can propagate in a stable way under slight disturbance of the constraint conditions and the initial perturbation of white noise.
Singh, K
2015-01-01
Mobile phone (MP) is commonly used communication tool. Electromagnetic waves (EMWs) emitted from MP may have potential health hazards. So, it was planned to study the effect of electromagnetic waves (EMWs) emitted from the mobile phone on brainstem auditory evoked potential (BAEP) in male subjects in the age group of 20-40 years. BAEPs were recorded using standard method of 10-20 system of electrode placement and sound click stimuli of specified intensity, duration and frequency.Right ear was exposed to EMW emitted from MP for about 10 min. On comparison of before and after exposure to MP in right ear (found to be dominating ear), there was significant increase in latency of II, III (p < 0.05) and V (p < 0.001) wave, amplitude of I-Ia wave (p < 0.05) and decrease in IPL of III-V wave (P < 0.05) after exposure to MP. But no significant change was found in waves of BAEP in left ear before vs after MP. On comparison of right (having exposure routinely as found to be dominating ear) and left ears (not exposed to MP), before exposure to MP, IPL of IIl-V wave and amplitude of V-Va is more (< 0.001) in right ear compared to more latency of III and IV wave (< 0.001) in left ear. After exposure to MP, the amplitude of V-Va was (p < 0.05) more in right ear compared to left ear. In conclusion, EMWs emitted from MP affects the auditory potential.
Partial wave analysis of the reaction p (3.5 GeV) + p → pK+ Λ to search for the " ppK-" bound state
NASA Astrophysics Data System (ADS)
Agakishiev, G.; Arnold, O.; Belver, D.; Belyaev, A.; Berger-Chen, J. C.; Blanco, A.; Böhmer, M.; Boyard, J. L.; Cabanelas, P.; Chernenko, S.; Dybczak, A.; Epple, E.; Fabbietti, L.; Fateev, O.; Finocchiaro, P.; Fonte, P.; Friese, J.; Fröhlich, I.; Galatyuk, T.; Garzón, J. A.; Gernhäuser, R.; Göbel, K.; Golubeva, M.; González-Díaz, D.; Guber, F.; Gumberidze, M.; Heinz, T.; Hennino, T.; Holzmann, R.; Ierusalimov, A.; Iori, I.; Ivashkin, A.; Jurkovic, M.; Kämpfer, B.; Karavicheva, T.; Koenig, I.; Koenig, W.; Kolb, B. W.; Kornakov, G.; Kotte, R.; Krása, A.; Krizek, F.; Krücken, R.; Kuc, H.; Kühn, W.; Kugler, A.; Kunz, T.; Kurepin, A.; Ladygin, V.; Lalik, R.; Lapidus, K.; Lebedev, A.; Lopes, L.; Lorenz, M.; Maier, L.; Mangiarotti, A.; Markert, J.; Metag, V.; Michel, J.; Müntz, C.; Münzer, R.; Naumann, L.; Pachmayer, Y. C.; Palka, M.; Parpottas, Y.; Pechenov, V.; Pechenova, O.; Pietraszko, J.; Przygoda, W.; Ramstein, B.; Reshetin, A.; Rustamov, A.; Sadovsky, A.; Salabura, P.; Schmah, A.; Schwab, E.; Siebenson, J.; Sobolev, Yu. G.; Spataro, S.; Spruck, B.; Ströbele, H.; Stroth, J.; Sturm, C.; Tarantola, A.; Teilab, K.; Tlusty, P.; Traxler, M.; Tsertos, H.; Vasiliev, T.; Wagner, V.; Weber, M.; Wendisch, C.; Wüstenfeld, J.; Yurevich, S.; Zanevsky, Y.; Sarantsev, A. V.
2015-03-01
Employing the Bonn-Gatchina partial wave analysis framework (PWA), we have analyzed HADES data of the reaction p (3.5 GeV) + p → pK+ Λ. This reaction might contain information about the kaonic cluster " ppK-" (with quantum numbers JP =0- and total isospin I = 1 / 2) via its decay into pΛ. Due to interference effects in our coherent description of the data, a hypothetical K ‾ NN (or, specifically " ppK-") cluster signal need not necessarily show up as a pronounced feature (e.g. a peak) in an invariant mass spectrum like pΛ. Our PWA analysis includes a variety of resonant and non-resonant intermediate states and delivers a good description of our data (various angular distributions and two-hadron invariant mass spectra) without a contribution of a K ‾ NN cluster. At a confidence level of CLs = 95% such a cluster cannot contribute more than 2-12% to the total cross section with a pK+ Λ final state, which translates into a production cross-section between 0.7 μb and 4.2 μb, respectively. The range of the upper limit depends on the assumed cluster mass, width and production process.
Partial wave analysis of the reaction p(3.5 GeV) + p → pK+ Λ to search for the "ppK–" bound state
Agakishiev, G.; Arnold, O.; Belver, D.; ...
2015-01-26
Employing the Bonn–Gatchina partial wave analysis framework (PWA), we have analyzed HADES data of the reaction p(3.5GeV) + p → pK+Λ. This reaction might contain information about the kaonic cluster “ppK-” (with quantum numbers JP=0- and total isospin I =1/2) via its decay into pΛ. Due to interference effects in our coherent description of the data, a hypothetical K ¯NN (or, specifically “ppK-”) cluster signal need not necessarily show up as a pronounced feature (e.g. a peak) in an invariant mass spectrum like pΛ. Our PWA analysis includes a variety of resonant and non-resonant intermediate states and delivers a goodmore » description of our data (various angular distributions and two-hadron invariant mass spectra) without a contribution of a K ¯NN cluster. At a confidence level of CLs=95% such a cluster cannot contribute more than 2–12% to the total cross section with a pK+ Λ final state, which translates into a production cross-section between 0.7 μb and 4.2 μb, respectively. The range of the upper limit depends on the assumed cluster mass, width and production process.« less
NASA Astrophysics Data System (ADS)
Ford, Christopher; Benesh, Matthew; Son, Seok-Kyun; Kataoka, Masaya; Barnes, Crispin; McNeil, Robert; Griffiths, Jon; Jones, Geb; Farrer, Ian; Ritchie, David
2013-03-01
Surface acoustic waves (SAWs) in a GaAs/AlGaAs heterostructure generate an electrostatic wave which propagates at the sound velocity. This potential wave is capable of collecting electrons from a 2D electron gas (2DEG) and transporting them through a depleted channel. The SAW minima form a continuous series of dynamic quantum dots, each transporting a controllable number of electrons along the channel. The confinement of the electrons in each dot increases as the potential rises along the channel, ejecting electrons one-by-one back into the 2DEG above the Fermi energy. These electrons can travel several microns before thermalising. We measure their energy spectrum using a variable potential barrier upstream as the channel is squeezed by split gates, and correlate this with the SAW-driven current along the channel. Now at RWTH Aachen
NASA Astrophysics Data System (ADS)
Zeyl, Timothy; Yin, Erwei; Keightley, Michelle; Chau, Tom
2016-04-01
Objective. Error-related potentials (ErrPs) have the potential to guide classifier adaptation in BCI spellers, for addressing non-stationary performance as well as for online optimization of system parameters, by providing imperfect or partial labels. However, the usefulness of ErrP-based labels for BCI adaptation has not been established in comparison to other partially supervised methods. Our objective is to make this comparison by retraining a two-step P300 speller on a subset of confident online trials using naïve labels taken from speller output, where confidence is determined either by (i) ErrP scores, (ii) posterior target scores derived from the P300 potential, or (iii) a hybrid of these scores. We further wish to evaluate the ability of partially supervised adaptation and retraining methods to adjust to a new stimulus-onset asynchrony (SOA), a necessary step towards online SOA optimization. Approach. Eleven consenting able-bodied adults attended three online spelling sessions on separate days with feedback in which SOAs were set at 160 ms (sessions 1 and 2) and 80 ms (session 3). A post hoc offline analysis and a simulated online analysis were performed on sessions two and three to compare multiple adaptation methods. Area under the curve (AUC) and symbols spelled per minute (SPM) were the primary outcome measures. Main results. Retraining using supervised labels confirmed improvements of 0.9 percentage points (session 2, p < 0.01) and 1.9 percentage points (session 3, p < 0.05) in AUC using same-day training data over using data from a previous day, which supports classifier adaptation in general. Significance. Using posterior target score alone as a confidence measure resulted in the highest SPM of the partially supervised methods, indicating that ErrPs are not necessary to boost the performance of partially supervised adaptive classification. Partial supervision significantly improved SPM at a novel SOA, showing promise for eventual online SOA
Pal, Tanushree; Joshi, Hardik; Ramaa, C S
2014-01-01
Recent era aims at developing safer partial Peroxisome proliferator-activated receptor-γ (PPAR- γ) agonists in order to dodge the toxicity issues related to full agonists. With a view to develop non-thiazolidinediones as partial PPAR-γ agonists, novel analogues of oxazol-5-ones (3a-3q) were designed and virtually analyzed for their molecular and drug like properties. The newly synthesized compounds were further evaluated for their preliminary cytotoxicity in a panel of eight cancer cell lines using four concentrations at 10- fold dilutions. Sulforhodamine B (SRB) protein assay was used to estimate cell stability or growth. All the compounds demonstrated distinct effect in the extent of cytotoxicity in the breast cancer cell line MCF-7 with 3g specifically exhibiting partial PPAR-γ agonist activity and adipogenesis stimulating ability.
Continuous-wave infrared optical nerve stimulation for potential diagnostic applications
NASA Astrophysics Data System (ADS)
Tozburun, Serhat; Cilip, Christopher M.; Lagoda, Gwen A.; Burnett, Arthur L.; Fried, Nathaniel M.
2010-09-01
Optical nerve stimulation using infrared laser radiation has recently been developed as a potential alternative to electrical nerve stimulation. However, recent studies have focused primarily on pulsed delivery of the laser radiation and at relatively low pulse rates. The objective of this study is to demonstrate faster optical stimulation of the prostate cavernous nerves using continuous-wave (cw) infrared laser radiation for potential diagnostic applications. A thulium fiber laser (λ=1870 nm) is used for noncontact optical stimulation of the rat prostate cavernous nerves in vivo. Optical nerve stimulation, as measured by an intracavernous pressure (ICP) response in the penis, is achieved with the laser operating in either cw mode, or with a 5-ms pulse duration at 10, 20, 30, 40, 50, and 100 Hz. Successful optical stimulation is observed to be primarily dependent on a threshold nerve temperature (42 to 45 °C), rather than an incident fluence, as previously reported. cw optical nerve stimulation provides a significantly faster ICP response time using a lower power (and also less expensive) laser than pulsed stimulation. cw optical nerve stimulation may therefore represent an alternative mode of stimulation for intraoperative diagnostic applications where a rapid response is critical, such as identification of the cavernous nerves during prostate cancer surgery.
Continuous-wave infrared optical nerve stimulation for potential diagnostic applications.
Tozburun, Serhat; Cilip, Christopher M; Lagoda, Gwen A; Burnett, Arthur L; Fried, Nathaniel M
2010-01-01
Optical nerve stimulation using infrared laser radiation has recently been developed as a potential alternative to electrical nerve stimulation. However, recent studies have focused primarily on pulsed delivery of the laser radiation and at relatively low pulse rates. The objective of this study is to demonstrate faster optical stimulation of the prostate cavernous nerves using continuous-wave (cw) infrared laser radiation for potential diagnostic applications. A thulium fiber laser (λ=1870 nm) is used for noncontact optical stimulation of the rat prostate cavernous nerves in vivo. Optical nerve stimulation, as measured by an intracavernous pressure (ICP) response in the penis, is achieved with the laser operating in either cw mode, or with a 5-ms pulse duration at 10, 20, 30, 40, 50, and 100 Hz. Successful optical stimulation is observed to be primarily dependent on a threshold nerve temperature (42 to 45 °C), rather than an incident fluence, as previously reported. cw optical nerve stimulation provides a significantly faster ICP response time using a lower power (and also less expensive) laser than pulsed stimulation. cw optical nerve stimulation may therefore represent an alternative mode of stimulation for intraoperative diagnostic applications where a rapid response is critical, such as identification of the cavernous nerves during prostate cancer surgery.
NASA Astrophysics Data System (ADS)
Kurz, Ph.; Förster, F.; Nordström, L.; Bihlmayer, G.; Blügel, S.
2004-01-01
The massively parallelized full-potential linearized augmented plane-wave bulk and film program FLEUR for first-principles calculations in the context of density functional theory was adapted to allow calculations of materials with complex magnetic structures—i.e., with noncollinear spin arrangements and incommensurate spin spirals. The method developed makes no shape approximation to the charge density and works with the continuous vector magnetization density in the interstitial and vacuum region and a collinear magnetization density in the spheres. We give an account of the implementation. Important technical aspects, such as the formulation of a constrained local moment method in a full-potential method that works with a vector magnetization density to deal with specific preselected nonstationary-state spin configurations, the inclusion of the generalized gradient approximation in a noncollinear framework, and the spin-relaxation method are discussed. The significance and validity of different approximations are investigated. We present examples to the various strategies to explore the magnetic ground state, metastable states, and magnetic phase diagrams by relaxation of spin arrangements or by performing calculations for constraint spin configurations to invest the functional dependence of the total energy and magnetic moment with respect to external parameters.
Nesmerak, Karel; Toropov, Andrey A; Toropova, Alla P; Kohoutova, Petra; Waisser, Karel
2013-09-01
Optimal descriptors calculated with Simplified Molecular Input Line Entry System (SMILES) notation have been used in quantitative structure-property relationships (QSPR) of half-wave potential of N-benzylsalicylthioamides. The QSPR developed is one-variable model based on the optimal descriptors calculated with the Monte Carlo method. The approach has been checked up with three random splits into the training and test sets. Mechanistic interpretations (structural alerts related to the half-wave potential) of the model are discussed. Copyright © 2013 Elsevier Masson SAS. All rights reserved.
Andreev, Pavel A; Iqbal, Z
2016-03-01
We consider the separate spin evolution of electrons and positrons in electron-positron and electron-positron-ion plasmas. We consider the oblique propagating longitudinal waves in these systems. Working in a regime of high-density n(0) ∼ 10(27) cm(-3) and high-magnetic-field B(0)=10(10) G, we report the presence of the spin-electron acoustic waves and their dispersion dependencies. In electron-positron plasmas, similarly to the electron-ion plasmas, we find one spin-electron acoustic wave (SEAW) at the propagation parallel or perpendicular to the external field and two spin-electron acoustic waves at the oblique propagation. At the parallel or perpendicular propagation of the longitudinal waves in electron-positron-ion plasmas, we find four branches: the Langmuir wave, the positron-acoustic wave, and a pair of waves having spin nature, they are the SEAW and the wave discovered in this paper, called the spin-electron-positron acoustic wave (SEPAW). At the oblique propagation we find eight longitudinal waves: the Langmuir wave, the Trivelpiece--Gould wave, a pair of positron-acoustic waves, a pair of SEAWs, and a pair of SEPAWs. Thus, for the first time, we report the existence of the second positron-acoustic wave existing at the oblique propagation and the existence of SEPAWs.
NASA Astrophysics Data System (ADS)
Steinczinger, Zsuzsanna; Jóvári, Pál; Pusztai, László
2017-01-01
Neutron- and x-ray weighted total structure factors of liquid water have been calculated on the basis of the intermolecular parts of partial radial distribution functions resulting from various computer simulations. The approach includes reverse Monte Carlo (RMC) modelling of these partials, using realistic flexible molecules, and the calculation of experimental diffraction data, including the intramolecular contributions, from the RMC particle configurations. The procedure has been applied to ten sets of intermolecular partial radial distribution functions obtained from various computer simulations, including one set from an ab initio molecular dynamics, of water. It is found that modern polarizable water potentials, such as SWM4-DP and BK3 are the most successful in reproducing measured diffraction data.
NASA Astrophysics Data System (ADS)
Bowley, Kevin; Atallah, Eyad; Gyakum, John
2017-04-01
Zonal available potential energy (ZAPE) is an estimate of the amount of potential energy in the atmosphere available for conversion to kinetic energy, providing a good proxy for the overall strength of the general circulation. Previous studies have estimated total hemispheric ZAPE, ZAPE generation, and conversion to kinetic energy, and proposed physical mechanisms to describe the annual ZAPE cycle as well as short term (sub-seasonal to synoptic) APE depletion events. Large, short term modulations of ZAPE have been shown to be associated with impactful weather events in the mid- and high-latitudes, including severe cyclones and high-amplitude ridging and blocking events In this study, we examine the association of significant synoptic time-scale increases in ZAPE with dynamic tropopause wave break events. ZAPE buildup events are determined using a 1979-2011 daily Northern Hemisphere (20˚ -85˚ N) ZAPE climatology calculated from the National Centers for Environmental Prediction (NCEP) Department of Energy (DOE) Reanalysis 2 global reanalysis dataset in an isobaric framework. To diagnose the importance of wave breaks in the troposphere, we objectively identify wave breaks using potential temperature on the dynamic tropopause, identifying and tracking both anti-cyclonic (LC1) and cyclonic (LC2) wave breaks during the 1979-2011 period. Our results indicate that LC1 wave break events in the equatorward jet exit regions appear to play an important role in ZAPE buildup events. The formation of these anti-cyclonic wave break events result in the development of statistically significant warm-core high pressure anomalies in these regions, acting to reduce baroclinic conversions. We will further demonstrate that changes in LC2 wave break activity in the climatological storm track during ZAPE buildup events are indicative of notable changes to the regions of significant cyclone activity, which are occurring in response to shifts and elongations of the jet stream.
An integral formulation for wave propagation on weakly non-uniform potential flows
NASA Astrophysics Data System (ADS)
Mancini, Simone; Astley, R. Jeremy; Sinayoko, Samuel; Gabard, Gwénaël; Tournour, Michel
2016-12-01
An integral formulation for acoustic radiation in moving flows is presented. It is based on a potential formulation for acoustic radiation on weakly non-uniform subsonic mean flows. This work is motivated by the absence of suitable kernels for wave propagation on non-uniform flow. The integral solution is formulated using a Green's function obtained by combining the Taylor and Lorentz transformations. Although most conventional approaches based on either transform solve the Helmholtz problem in a transformed domain, the current Green's function and associated integral equation are derived in the physical space. A dimensional error analysis is developed to identify the limitations of the current formulation. Numerical applications are performed to assess the accuracy of the integral solution. It is tested as a means of extrapolating a numerical solution available on the outer boundary of a domain to the far field, and as a means of solving scattering problems by rigid surfaces in non-uniform flows. The results show that the error associated with the physical model deteriorates with increasing frequency and mean flow Mach number. However, the error is generated only in the domain where mean flow non-uniformities are significant and is constant in regions where the flow is uniform.
Hammody, Z; Huleihel, M; Salman, A; Argov, S; Moreh, R; Katzir, A; Mordechai, S
2007-11-01
The present study focuses on evaluating the potential of flattened AgClBr fibre-optic evanescent wave spectroscopy (FTIR-FEWS) technique for detection and identification of cancer cells in vitro using cell culture as a model system. The FTIR-FEWS results are compared to those from FTIR-microspectroscopy (FTIR-MSP) method extensively used to identify spectral properties of intact cells. Ten different samples of control and malignant cells were measured in parallel by the above two methods. Our results show a significant similarity between the results obtained by the two methodologies. The absorbance level of Amide I/Amide II, phosphates and carbohydrates were significantly altered in malignant compared to the normal cells using both systems. Thus, common biomarkers such as Amide I/Amide II, phosphate and carbohydrate levels can be derived to discern between normal and cancer cells. However, marked differences are also noted between the two methodologies in the protein bands due to CH3 bending vibration (1480-1350 cm(-1)). The spectral differences may be attributed to the variation in the penetration depth of the two methodologies. The use of flattened fibre rather than the standard cylindrical fibre has several practical advantages and is considered as an important step towards in vivo measurements in real time, such as that of skin nevi and melanoma using special designs of fibre-optic-based sensors.
Ryan, K L; D'Andrea, J A; Jauchem, J R; Mason, P A
2000-02-01
Currently, technology is being developed that makes use of the millimeter wave (MMW) range (30-300 GHz) of the radio frequency region of the electromagnetic spectrum. As more and more systems come on line and are used in everyday applications, the possibility of inadvertent exposure of personnel to MMWs increases. To date, there has been no published discussion regarding the health effects of MMWs; this review attempts to fill that void. Because of the shallow depth of penetration, the energy and, therefore, heat associated with MMWs will be deposited within the first 1-2 mm of human skin. MMWs have been used in states of the former Soviet Union to provide therapeutic benefit in a number of diverse disease states, including skin disorders, gastric ulcers, heart disease and cancer. Conversely, the possibility exists that hazards might be associated with accidental overexposure to MMWs. This review attempts to critically analyze the likelihood of such acute effects as burn and eye damage, as well as potential long-term effects, including cancer.
Cheng, Jin; Yu, Kuang; Libisch, Florian; Dieterich, Johannes M; Carter, Emily A
2017-03-14
Quantum mechanical embedding theories partition a complex system into multiple spatial regions that can use different electronic structure methods within each, to optimize trade-offs between accuracy and cost. The present work incorporates accurate but expensive correlated wave function (CW) methods for a subsystem containing the phenomenon or feature of greatest interest, while self-consistently capturing quantum effects of the surroundings using fast but less accurate density functional theory (DFT) approximations. We recently proposed two embedding methods [for a review, see: Acc. Chem. Res. 2014 , 47 , 2768 ]: density functional embedding theory (DFET) and potential functional embedding theory (PFET). DFET provides a fast but non-self-consistent density-based embedding scheme, whereas PFET offers a more rigorous theoretical framework to perform fully self-consistent, variational CW/DFT calculations [as defined in part 1, CW/DFT means subsystem 1(2) is treated with CW(DFT) methods]. When originally presented, PFET was only tested at the DFT/DFT level of theory as a proof of principle within a planewave (PW) basis. Part 1 of this two-part series demonstrated that PFET can be made to work well with mixed Gaussian type orbital (GTO)/PW bases, as long as optimized GTO bases and consistent electron-ion potentials are employed throughout. Here in part 2 we conduct the first PFET calculations at the CW/DFT level and compare them to DFET and full CW benchmarks. We test the performance of PFET at the CW/DFT level for a variety of types of interactions (hydrogen bonding, metallic, and ionic). By introducing an intermediate CW/DFT embedding scheme denoted DFET/PFET, we show how PFET remedies different types of errors in DFET, serving as a more robust type of embedding theory.
Transport and localization of waves in ladder-shaped lattices with locally PT -symmetric potentials
NASA Astrophysics Data System (ADS)
Nguyen, Ba Phi; Kim, Kihong
2016-12-01
We study numerically the transport and localization properties of waves in ordered and disordered ladder-shaped lattices with local PT symmetry. Using a transfer matrix method, we calculate the transmittance and the reflectance for the individual channels and the Lyapunov exponent for the whole system. In the absence of disorder, we find that when the gain or loss parameter ρ is smaller than the interchain coupling parameter tv, the transmittance and the reflectance are periodic functions of the system size, whereas when ρ is larger than tv, the transmittance is found to be an exponentially decaying function while the reflectance attains a saturation value in the thermodynamic limit. For a fixed system size, there appear perfect transmission resonances in each individual channel at several values of the gain or loss strength smaller than tv. A singular behavior of the transmittance is also found to appear at various values of ρ for a given system size. When disorder is inserted into the on-site potentials, these behaviors are changed substantially due to the interplay between disorder and the gain or loss effect. When ρ is smaller than tv, we find that the presence of locally PT -symmetric potentials suppresses Anderson localization, as compared to the localization in the corresponding Hermitian system. When ρ is larger than tv, we find that localization becomes more pronounced at higher gain or loss strengths. We also find that the phenomenon of anomalous localization occurs in disordered locally PT -symmetric systems precisely at the spectral positions E =0 and E =±√{tv2-ρ2 } . The anomaly at the band center manifests as a sharp peak, contrary to the conventional cases, whereas the anomalies at E =±√{tv2-ρ2 } manifest as sharp dips.
Wave Energy Potential in the Eastern Mediterranean Levantine Basin. An Integrated 10-year Study
2014-01-01
regions. The wave region of Madeira Archipelagos is the target area for Ref. [63]. Compared to the above studies, the main advantages of the approach and...Rusu E, Pilar P, Soares CG. Evaluation of the wave conditions in Madeira Ar- chipelago with spectral models. Ocean Eng 2008;35(13):1357e71. [64] Rusu
Lin, Fang; Jin, Chuanhong
2014-03-01
We proposed a new algorithm that retrieves the projected potentials from the EW of object. This algorithm is based on the traditional multislice method which involves the convolution operation in calculation. The retrieved potential is complex including both the electrostatic and absorptive components. Tests with the simulated exit waves of a 200 K InP crystal prove the algorithm effective for objects in wide thickness range. For thick specimen where dynamical electron diffraction prevails, the retrieved potential could present structure and chemical information of object by completely mapping an atom's scattering potential during interaction with incident electrons.
Marker vaccine potential of a foot-and-mouth disease virus with a partial VP1 G-H loop deletion.
Fowler, V L; Knowles, N J; Paton, D J; Barnett, P V
2010-04-26
Previous work in cattle and pigs demonstrated that protection against foot-and-mouth disease (FMD) could be achieved following vaccination with chimeric foot-and-mouth disease virus (FMDV) vaccines, in which the VP1 G-H loop had been substituted with that from another serotype. This indicated that the VP1 G-H loop may not be essential for the protection of natural hosts against FMDV. If this could be substantiated there would be potential to develop FMD marker vaccines, characterised by the absence of this region. Here, we investigate the serological responses to vaccination with a virus with a partial VP1 G-H loop deletion in order to determine the likelihood of achieving protection and the potential of this virus as a marker vaccine. Inactivated, oil adjuvanted, vaccines, consisting of chemically inactivated virus with or without a partially deleted VP1 G-H loop, were used to immunise cattle. Serum was collected on days 0, 7, 14 and 21 and antibody titres calculated using the virus neutralisation test (VNT) to estimate the likelihood of protection. We predict a good likelihood that cattle vaccinated with a vaccine characterised by a partial VP1 G-H loop would be protected against challenge with the same virus containing the VP1 G-H loop. We also present evidence on the potential of such a construct to act as a marker vaccine, when used in conjunction with a novel serological test.
Pietrzak, Robert H.; Goldstein, Risë B.; Southwick, Steven M.; Grant, Bridget F.
2010-01-01
Background While it is well known that personality disorders are associated with trauma exposure and PTSD, limited nationally representative data are available on DSM-IV personality disorders that co-occur with posttraumatic stress disorder (PTSD) and partial PTSD. Methods Face-to-face interviews were conducted with 34,653 adults participating in the Wave 2 National Epidemiologic Survey on Alcohol and Related Conditions. Logistic regression analyses controlling for sociodemographics and additional psychiatric comorbidity evaluated associations of PTSD and partial PTSD with personality disorders. Results Prevalence rates of lifetime PTSD and partial PTSD were 6.4% and 6.6%, respectively. After adjustment for sociodemographic characteristics and additional psychiatric comorbidity, respondents with full PTSD were more likely than trauma controls to meet criteria for schizotypal, narcissistic, and borderline personality disorders (ORs=2.1–2.5); and respondents with partial PTSD were more likely than trauma controls to meet diagnostic criteria for borderline (OR=2.0), schizotypal (OR=1.8), and narcissistic (OR=1.6) PDs. Women with PTSD were more likely than controls to have obsessive-compulsive PD. Women with partial PTSD were more likely than controls to have antisocial PD; and men with partial PTSD were less likely than women with partial PTSD to have avoidant PD. Conclusions PTSD and partial PTSD are associated with borderline, schizotypal, and narcissistic personality disorders. Modestly higher rates of obsessive-compulsive PD were observed among women with full PTSD, and of antisocial PD among women with partial PTSD. PMID:20950823
Calbo, Joaquín; Viruela, Rafael; Ortí, Enrique; Aragó, Juan
2016-12-05
A high-level ab initio protocol to compute accurate electron affinities and half-wave reduction potentials is presented and applied for a series of electron-acceptor compounds with potential interest in organic electronics and redox flow batteries. The comprehensive comparison between the theoretical and experimental electron affinities not only proves the reliability of the theoretical G3(MP2) approach employed but also calls into question certain experimental measurements, which need to be revised. By using the thermodynamic cycle for the one-electron attachment reaction A+e(-) →A(-) , theoretical estimates for the first half-wave reduction potential have been computed along the series of electron-acceptor systems investigated, with maximum deviations from experiment of only 0.2 V. The precise inspection of the terms contributing to the half-wave reduction potential shows that the difference in the free energy of solvation between the neutral and the anionic species (ΔΔGsolv ) plays a crucial role in accurately estimating the electron-acceptor properties in solution, and thus it cannot be considered constant even in a family of related compounds. This term, which can be used to explain the occasional lack of correlation between electron affinities and reduction potentials, is rationalized by the (de)localization of the additional electron involved in the reduction process along the π-conjugated chemical structure.
Cai, X
2014-04-16
The effect of the incommensurate potential is studied for the one-dimensional p-wave superconductor. It is determined by analyzing various properties, such as the superconducting gap, the long-range order of the correlation function, the inverse participation ratio and the Z2 topological invariant, etc. In particular, two important aspects of the effect are investigated: (1) as disorder, the incommensurate potential destroys the superconductivity and drives the system into the Anderson localized phase; (2) as a quasi-periodic potential, the incommensurate potential causes band splitting and turns the system with certain chemical potential into the band insulator phase. A full phase diagram is also presented in the chemical potential-incommensurate potential strength plane.
NASA Astrophysics Data System (ADS)
Lu, Xian; Chen, Cao; Yudin, Valery; Chu, Xinzhao; Yu, Zhibin; Fong, Weichun
We provide the first report on the vertical evolution of gravity wave potential energy and vertical wavenumber spectrum from 30 to 110 km in the Antarctic winter seasons from 2011 to 2013. These wave properties were derived from temperature observations made with an Fe Boltzmann lidar at McMurdo (77.8(°) S,166.7(°) E), Antarctica. The potential energy density per unit mass (Epm) grows exponentially with a scale height of 13 km in the Rayleigh region (30-70 km), where waves are partially dissipated or saturated. However, the vertical variation of Epm is not uniformly exponential in the MLT region. An unusually rapid increase of Epm is observed from 86 to 94 km with a scale height close to freely propagating waves (6km), suggestive of very small dissipations; while above 94 km, Epm barely increases with altitude implying that gravity waves dissipate severely. A new finding of this study is that the shape of vertical wavenumber spectra possesses two distinctive ranges. From 1 to 4 km, its yearly mean slope is close to the canonical value of -3, as predicted by various theories. From 4 to 12 km, its mean value is only about -1.5. This may suggest that waves are saturated more for wavelengths of 1-4 km than for longer ones. The characteristic vertical wavelengths increase from 12 -18 km in the Rayleigh region to >20 km in the MLT region. It is intriguing that the slopes and shapes of wavenumber spectra do not evolve considerably with altitude, whereas spectral power densities increase by 5-10 times. The mechanisms for the vertical evolution of gravity wave Epm and spectra deserve further investigations.
NASA Astrophysics Data System (ADS)
Benoit, Michel; Yates, Marissa L.; Raoult, Cécile
2017-04-01
Efficient and accurate numerical models simulating wave propagation are required for a variety of engineering projects including the evaluation of coastal risks, the design of protective coastal structures, and the estimation of the potential for marine renewable energy devices. Nonlinear and dispersive effects are particularly significant in the coastal zone where waves interact with the bottom, the shoreline, and coastal structures. The main challenge in developing a numerical models is finding a compromise between computational efficiency and the required accuracy of the simulated wave field. Here, a potential approach is selected and the (fully nonlinear) water wave problem is formulated using the Euler-Zakharov equations (Zakharov, 1968) describing the temporal evolution of the free surface elevation and velocity potential. The proposed model (Yates and Benoit, 2015) uses a spectral approach in the vertical (i.e. the vertical variation of the potential is approximated by a linear combination of the first NT+1 Chebyshev polynomials, following the work of Tian and Sato (2008)). The Zakharov equations are integrated in time using a fourth-order Runge-Kutta scheme with a constant time step. At each sub-timestep, the Laplace Boundary Value Problem (BVP) is solved to estimate the free surface vertical velocity using the spectral approach, with typical values of NT between 5 to 8 for practical applications. The 1DH version of the code is validated with comparisons to the experimental data set of Becq-Girard et al. (1999), which studied the propagation of irregular waves over a beach profile with a submerged bar. The nonlinear and dispersive capacities of the model are verified with the correct representation of wave-wave interactions, in particular the transfer of energy between different harmonic components during wave propagation (analysis of the transformation of the variance spectrum along the channel). Evolution of wave skewness, asymmetry and kurtosis along the
Martínez-Gómez, Maria A; Villanueva-Camañas, R M; Sagrado, Salvador; Medina-Hernández, Maria J
2006-11-01
The enantiomeric resolution of compounds using HSA by means of affinity EKC (AEKC)-partial filling technique is the result of a delicate balance between different experimental variables such as protein concentration, running pH (background electrophoretic buffer (BGE), protein, and compound solutions), and plug length. In this paper, the possibility of using HSA as chiral selector for enantioseparation of 28 basic drugs using this methodology is studied. The effect of the physicochemical parameters, the structural properties of compounds, and compound-HSA protein binding percentages over their chiral resolution with HSA is outlined. Based on the results obtained, a decision tree is proposed for the "a priori" prediction of the capability of HSA for enantioseparation of basic drugs in AEKC. The results obtained indicated that enantioresolution of basic compounds with HSA depends on the hydrophobicity, polarity, and molar volume of compounds.
Moskal, Joseph R; Burgdorf, Jeffrey; Kroes, Roger A; Brudzynski, Stefan M; Panksepp, Jaak
2011-10-01
Deficits in social approach behavior, rough-and-tumble play, and speech abnormalities are core features of autism that can be modeled in laboratory rats. Human twin studies show that autism has a strong genetic component, and a recent review has identified 99 genes that are dysregulated in human autism. Bioinformatic analysis of these 99 genes identified the NMDA receptor complex as a significant interaction hub based on protein-protein interactions. The NMDA receptor glycine site partial agonist d-cycloserine has been shown to treat the core symptom of social withdrawal in autistic children. Here, we show that rats selectively bred for low rates of play-induced pro-social ultrasonic vocalizations (USVs) can be used to model certain core symptoms of autism. Low-line animals engage in less social contact time with conspecifics, show lower rates of play induced pro-social USVs, and show an increased proportion of non-frequency modulated (i.e. monotonous) ultrasonic vocalizations, compared to non-selectively bred random-line animals. Gene expression patterns in the low-line animals show significant enrichment in autism-associated genes and the NMDA receptor family was identified as a significant hub. Treatment of low-line animals with the NMDAR glycine site partial agonist GLYX-13 rescued the deficits in play-induced pro-social 50-kHz and reduced monotonous USVs. Thus, the NMDA receptor has been shown to play a functional role in autism, and GLYX-13 shows promise for the treatment of autism. We dedicate this paper to Ole Ivar Lovaas (May 8, 1927-August 2, 2010), a pioneer in the field of autism. Copyright © 2011 Elsevier Ltd. All rights reserved.
NASA Astrophysics Data System (ADS)
Sant, Marco; Gabrieli, Andrea; Demontis, Pierfranco; Suffritti, Giuseppe B.
2016-03-01
The InfiniCharges computer program, for generating reliable partial charges for molecular simulations in periodic systems, is here presented. This tool is an efficient implementation of the recently developed DM-REPEAT method, where the stability of the resulting charges, over a large set of fitting regions, is obtained through the simultaneous fit of multiple electrostatic potential (ESP) configurations together with the total dipole fluctuations (TDF). Besides DM-REPEAT, the program can also perform standard REPEAT fit and its multiframe extension (M-REPEAT), with the possibility to restrain the charges to an arbitrary value. Finally, the code is employed to generate partial charges for ZIF-90, a microporous material of the metal organic frameworks (MOFs) family, and an extensive analysis of the results is carried out.
NASA Astrophysics Data System (ADS)
Kato, Tsuyoshi; Ide, Yoshihiro; Yamanouchi, Kaoru
2015-12-01
We first calculate the ground-state molecular wave function of 1D model H2 molecule by solving the coupled equations of motion formulated in the extended multi-configuration time-dependent Hartree-Fock (MCTDHF) method by the imaginary time propagation. From the comparisons with the results obtained by the Born-Huang (BH) expansion method as well as with the exact wave function, we observe that the memory size required in the extended MCTDHF method is about two orders of magnitude smaller than in the BH expansion method to achieve the same accuracy for the total energy. Second, in order to provide a theoretical means to understand dynamical behavior of the wave function, we propose to define effective adiabatic potential functions and compare them with the conventional adiabatic electronic potentials, although the notion of the adiabatic potentials is not used in the extended MCTDHF approach. From the comparison, we conclude that by calculating the effective potentials we may be able to predict the energy differences among electronic states even for a time-dependent system, e.g., time-dependent excitation energies, which would be difficult to be estimated within the BH expansion approach.
Kato, Tsuyoshi; Ide, Yoshihiro; Yamanouchi, Kaoru
2015-12-31
We first calculate the ground-state molecular wave function of 1D model H{sub 2} molecule by solving the coupled equations of motion formulated in the extended multi-configuration time-dependent Hartree-Fock (MCTDHF) method by the imaginary time propagation. From the comparisons with the results obtained by the Born-Huang (BH) expansion method as well as with the exact wave function, we observe that the memory size required in the extended MCTDHF method is about two orders of magnitude smaller than in the BH expansion method to achieve the same accuracy for the total energy. Second, in order to provide a theoretical means to understand dynamical behavior of the wave function, we propose to define effective adiabatic potential functions and compare them with the conventional adiabatic electronic potentials, although the notion of the adiabatic potentials is not used in the extended MCTDHF approach. From the comparison, we conclude that by calculating the effective potentials we may be able to predict the energy differences among electronic states even for a time-dependent system, e.g., time-dependent excitation energies, which would be difficult to be estimated within the BH expansion approach.
NASA Astrophysics Data System (ADS)
Amour, L.; Faupin, J.; Raoux, T.
2009-03-01
We pursue the analysis of the Schrödinger operator on the unit interval in inverse spectral theory initiated in the work of Amour and Raoux ["Inverse spectral results for Schrödinger operators on the unit interval with potentials in Lp spaces," Inverse Probl. 23, 2367 (2007)]. While the potentials in the work of Amour and Raoux belong to L1 with their difference in Lp (1≤p<∞), we consider here potentials in Wk,1 spaces having their difference in Wk,p, where 1≤p≤+∞, k ɛ{0,1,2}. It is proved that two potentials in Wk,1([0,1]) being equal on [a,1] are also equal on [0,1] if their difference belongs to Wk,p([0,a]) and if the number of their common eigenvalues is sufficiently high. Naturally, this number decreases as the parameter a decreases and as the parameters k and p increase.
Gaussian solitary waves and compactons in Fermi–Pasta–Ulam lattices with Hertzian potentials
James, Guillaume; Pelinovsky, Dmitry
2014-01-01
We consider a class of fully nonlinear Fermi–Pasta–Ulam (FPU) lattices, consisting of a chain of particles coupled by fractional power nonlinearities of order α>1. This class of systems incorporates a classical Hertzian model describing acoustic wave propagation in chains of touching beads in the absence of precompression. We analyse the propagation of localized waves when α is close to unity. Solutions varying slowly in space and time are searched with an appropriate scaling, and two asymptotic models of the chain of particles are derived consistently. The first one is a logarithmic Korteweg–de Vries (KdV) equation and possesses linearly orbitally stable Gaussian solitary wave solutions. The second model consists of a generalized KdV equation with Hölder-continuous fractional power nonlinearity and admits compacton solutions, i.e. solitary waves with compact support. When , we numerically establish the asymptotically Gaussian shape of exact FPU solitary waves with near-sonic speed and analytically check the pointwise convergence of compactons towards the limiting Gaussian profile. PMID:24808748
Ultrasonic Guided Wave Focus Inspection Potential of Bare and Coated Pipes
NASA Astrophysics Data System (ADS)
Mu, J.; Hua, J.; Rose, J. L.
2010-02-01
Ultrasonic guided waves in elastic bare pipes are studied from a theoretical point of view. Dispersion curves of both axisymmetric and non-axisymmetric waves are presented. The parameters of 4-channel focusing are calculated by a phased array focusing algorithm. Experimentally four defects are detected in a cased pipe inspection. The defect probability of detection is highly improved by applying the phased array focusing technique. Guided wave dispersion curves in coated pipes are calculated using a 1-D Semi-Analytical Finite Element (SAFE) technique. This theoretically driven hybrid SAFE method has perfectly tackled the guided wave problem in coated pipes, including dispersion curves (phase velocity dispersion curves and attenuation dispersion curves) and wave structures. The time delays and amplitudes of the 8-channel focusing in an 8 in sch40 coated pipe are calculated by the SAFE algorithm and input to the FEM simulation in ABAQUS®. Focusing performance is improved up to 67% by applying the coated pipe parameters compared with the bare pipe parameters.
Gaussian solitary waves and compactons in Fermi-Pasta-Ulam lattices with Hertzian potentials.
James, Guillaume; Pelinovsky, Dmitry
2014-05-08
We consider a class of fully nonlinear Fermi-Pasta-Ulam (FPU) lattices, consisting of a chain of particles coupled by fractional power nonlinearities of order α>1. This class of systems incorporates a classical Hertzian model describing acoustic wave propagation in chains of touching beads in the absence of precompression. We analyse the propagation of localized waves when α is close to unity. Solutions varying slowly in space and time are searched with an appropriate scaling, and two asymptotic models of the chain of particles are derived consistently. The first one is a logarithmic Korteweg-de Vries (KdV) equation and possesses linearly orbitally stable Gaussian solitary wave solutions. The second model consists of a generalized KdV equation with Hölder-continuous fractional power nonlinearity and admits compacton solutions, i.e. solitary waves with compact support. When [Formula: see text], we numerically establish the asymptotically Gaussian shape of exact FPU solitary waves with near-sonic speed and analytically check the pointwise convergence of compactons towards the limiting Gaussian profile.
Tavakoli, Paniz; Muller-Gass, Alexandra; Campbell, Kenneth
2015-03-01
Sleep deprivation has generally been observed to have a detrimental effect on tasks that require sustained attention for successful performance. It might however be possible to counter these effects by altering cognitive strategies. A recent semantic word priming study indicated that subjects used an effortful predictive-expectancy search of semantic memory following normal sleep, but changed to an automatic, effortless strategy following total sleep deprivation. Partial sleep deprivation occurs much more frequently than total sleep deprivation. The present study therefore employed a similar priming task following either 4h of sleep or following normal sleep. The purpose of the study was to determine whether partial sleep deprivation would also lead to a shift in cognitive strategy to compensate for an inability to sustain attention and effortful processing necessary for using the predicative expectancy strategy. Sixteen subjects were presented with word pairs, a prime and a target that were either strongly semantically associated (cat...dog), weakly associated (cow...barn) or not associated (apple...road). The subject's task was to determine if the target word was semantically associated to the prime. A strong priming effect was observed in both conditions. RTs were slower, accuracy lower, and N400 larger to unassociated targets, independent of the amount of sleep. The overall N400 did not differ as a function of sleep. The scalp distribution of the N400 was also similar following both normal sleep and sleep loss. There was thus little evidence of a difference in the processing of the target stimulus as a function of the amount sleep. Similarly, ERPs in the period between the onset of the prime and the subsequent target also did not differ between the normal sleep and sleep loss conditions. In contrast to total sleep deprivation, subjects therefore appeared to use a common predictive expectancy strategy in both conditions. This strategy does however require an
NASA Astrophysics Data System (ADS)
Angraini, Lily Maysari; Suparmi, Variani, Viska Inda
2010-12-01
SUSY quantum mechanics can be applied to solve Schrodinger equation for high dimensional system that can be reduced into one dimensional system and represented in lowering and raising operators. Lowering and raising operators can be obtained using relationship between original Hamiltonian equation and the (super) potential equation. In this paper SUSY quantum mechanics is used as a method to obtain the wave function and the energy level of the Modified Poschl Teller potential. The graph of wave function equation and probability density is simulated by using Delphi 7.0 programming language. Finally, the expectation value of quantum mechanics operator could be calculated analytically using integral form or probability density graph resulted by the programming.
Angraini, Lily Maysari; Suparmi,; Variani, Viska Inda
2010-12-23
SUSY quantum mechanics can be applied to solve Schrodinger equation for high dimensional system that can be reduced into one dimensional system and represented in lowering and raising operators. Lowering and raising operators can be obtained using relationship between original Hamiltonian equation and the (super) potential equation. In this paper SUSY quantum mechanics is used as a method to obtain the wave function and the energy level of the Modified Poschl Teller potential. The graph of wave function equation and probability density is simulated by using Delphi 7.0 programming language. Finally, the expectation value of quantum mechanics operator could be calculated analytically using integral form or probability density graph resulted by the programming.
Dynamics of zero-energy nonspreading non-Gaussian wave packets for a class of central potentials
Makowski, Adam J. Pepłowski, Piotr
2013-10-15
Zero-energy wave packets, coherent states, are constructed in such a way that they retain their shape during the time evolution for a large class of central potentials. The packets are not of the Gaussian type with −r{sup 2} dependence but, instead, their shape is determined by −r{sup 1/(μ+1/2)} with −1/2<μ<1/2. A very close quantum–classical correspondence is also shown, i.e., the well localized states travel along suitable classical trajectories. -- Highlights: •Central potentials are considered. •Nonspreading, non-Gaussian wave packets are constructed. •Time evolution of the zero-energy packets is studied. •Quantum–classical correspondence is discussed.
NASA Astrophysics Data System (ADS)
Yu, Fajun
2017-02-01
Starting from a discrete spectral problem, we derive a hierarchy of nonlinear discrete equations which include the Ablowitz-Ladik (AL) equation. We analytically study the discrete rogue-wave (DRW) solutions of AL equation with three free parameters. The trajectories of peaks and depressions of profiles for the first- and second-order DRWs are produced by means of analytical and numerical methods. In particular, we study the solutions with dispersion in parity-time ( P T ) symmetric potential for Ablowitz-Musslimani equation. And we consider the non-autonomous DRW solutions, parameters controlling and their interactions with variable coefficients, and predict the long-living rogue wave solutions. Our results might provide useful information for potential applications of synthetic P T symmetric systems in nonlinear optics and condensed matter physics.
Qian, W; Chen, X; Fu, D; Zou, J; Meng, J
2005-05-01
This paper reports the observation on the intersubgenomic heterosis for seed yield among hybrids between natural Brassica napus (A(n)A(n)C(n)C(n)) and a new type of B. napus with introgressions of genomic components of Brassica rapa (A(r)A(r)). This B. napus was selected from the progeny of B. napus x B. rapa and (B. napus x B. rapa) x B. rapa based on extensive phenotypic and cytological observation. Among the 129 studied partial intersubgenomic hybrids, which were obtained by randomly crossing 13 lines of the new type of B. napus in F(3) or BC(1)F(3) to 27 cultivars of B. napus from different regions as tester lines, about 90% of combinations exceeded the yield of their respective tester lines, whereas about 75% and 25% of combinations surpassed two elite Chinese cultivars, respectively. This strong heterosis was further confirmed by reevaluating 2 out of the 129 combinations in a successive year and by surveying hybrids between 20 lines of the new type of B. napus in BC(1)F(5) and its parental B. napus in two locations. Some DNA segments from B. rapa were identified with significant effects on seed yield and yield components of the new type of B. napus in BC(1)F(5) and intersubgenomic hybrids in positive or negative direction. It seems that the genomic components introgressed from B. rapa contributed to improvement of seed yield of rapeseed.
Khoder, Wael Y; Zilinberg, Katja; Waidelich, Raphaela; Stief, Christian G; Becker, Armin J; Pangratz, Thomas; Hennig, Georg; Sroka, Ronald
2012-06-01
Laparoscopic/robotic partial nephrectomy (LPN) is increasingly considered for small renal tumors (RT). This demands new compatible surgical tools for RT-resection, such as lasers, to optimize cutting and coagulation. This work aims to characterize ex vivo handling requirements for six medically approved laser devices emitting different light wavelengths (940, 1064, 1318, 1470, 1940, and 2010 nm) amenable for LPN. Incisions were made by laser fibers driven by a computer-controlled stepping motor allowing precise linear movement with a preset velocity at a fixed fiber-tip distance to tissue. Optical parameters were measured on 200 μm tissue slices. Cutting quality depended on power output, fiber velocity and fiber-tip distance to tissue. Contact manner is suitable for cutting while a noncontact manner (5 mm distance) induces coagulation. Ablation threshold differs for each wavelength. Ablation depth is proportional to power output (within limit) while axial and superficial coagulation remains mostly constant. Increased fiber velocity compromises the coagulation quality. Optical parameters of porcine kidney tissue demonstrate that renal absorption coefficient follows water absorption in the 2 μm region while for other spectral regions (900 to 1500 and 1 μm) the tissue effects are influenced by other chromophores and scattering. Tissue color changes demonstrate dependencies on irradiance, scan velocity, and wavelength. Current results clearly demonstrate that surgeons considering laser-assisted RT excisions should be aware of the mentioned technical parameters (power output, fiber velocity and fiber-tip tissue-distance) rather than wavelength only.
NASA Astrophysics Data System (ADS)
Khoder, Wael Y.; Zilinberg, Katja; Waidelich, Raphaela; Stief, Christian G.; Becker, Armin J.; Pangratz, Thomas; Hennig, Georg; Sroka, Ronald
2012-06-01
Laparoscopic/robotic partial nephrectomy (LPN) is increasingly considered for small renal tumors (RT). This demands new compatible surgical tools for RT-resection, such as lasers, to optimize cutting and coagulation. This work aims to characterize ex vivo handling requirements for six medically approved laser devices emitting different light wavelengths (940, 1064, 1318, 1470, 1940, and 2010 nm) amenable for LPN. Incisions were made by laser fibers driven by a computer-controlled stepping motor allowing precise linear movement with a preset velocity at a fixed fiber-tip distance to tissue. Optical parameters were measured on 200 μm tissue slices. Cutting quality depended on power output, fiber velocity and fiber-tip distance to tissue. Contact manner is suitable for cutting while a noncontact manner (5 mm distance) induces coagulation. Ablation threshold differs for each wavelength. Ablation depth is proportional to power output (within limit) while axial and superficial coagulation remains mostly constant. Increased fiber velocity compromises the coagulation quality. Optical parameters of porcine kidney tissue demonstrate that renal absorption coefficient follows water absorption in the 2 μm region while for other spectral regions (900 to 1500 and 1 μm) the tissue effects are influenced by other chromophores and scattering. Tissue color changes demonstrate dependencies on irradiance, scan velocity, and wavelength. Current results clearly demonstrate that surgeons considering laser-assisted RT excisions should be aware of the mentioned technical parameters (power output, fiber velocity and fiber-tip tissue-distance) rather than wavelength only.
Imaeda, Kenro; Kato, Takashi; Okayama, Naotsuka; Imai, Seiji; Sasaki, Makoto; Kataoka, Hiromi; Nakazawa, Takahiro; Ohara, Hirotaka; Kito, Yoshihiko; Itoh, Makoto
2004-10-01
Electrophysiological effects of endothelin-1 (ET-1) on circular smooth muscle of rat gastric antrum were investigated by using intracellular membrane potential recording techniques. ET-1 (10 nM) caused an initial hyperpolarization of the membrane which was followed by a sustained depolarization. ET-1 also increased the frequency but not the amplitude of slow waves. In the presence of the endothelin type A (ETA) receptor antagonist, BQ123 (1 microM), ET-1 (10 nM) depolarized the membrane and increased the frequency of slow waves, but without the initial hyperpolarization. The selective endothelin type B (ETB) receptor agonist, sarafotoxin S6c (10 nM), also depolarized the membrane and increased the frequency of slow waves. In the presence of the ETB receptor antagonist, BQ788 (1 microM), ET-1 (10 nM) hyperpolarized the membrane. However, in the presence of BQ788, ET-1 caused neither the depolarization nor the increase in the frequency of the slow waves. The ET-1-induced hyperpolarization was completely abolished by apamin (0.1 microM). In the presence of apamin, ET-1 depolarized the membrane and increased the frequency of slow waves. The ET-1-induced depolarization was significantly attenuated by 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid (DIDS, 0.3 mM). The increase of the frequency by ET-1 was observed both in the presence and absence of DIDS. These results suggest that, ET-1 hyperpolarizes the membrane by the activation of Ca2+-activated K+ channels via ETA receptors, and depolarizes the membrane by the activation of Ca2+-activated Cl- channels via ETB receptors. ET-1 also appears to increase the frequency of slow waves via ETB receptors, however this mechanism would seem to be independent of membrane depolarization.
Dynamics of zero-energy nonspreading non-Gaussian wave packets for a class of central potentials
NASA Astrophysics Data System (ADS)
Makowski, Adam J.; Pepłowski, Piotr
2013-10-01
Zero-energy wave packets, coherent states, are constructed in such a way that they retain their shape during the time evolution for a large class of central potentials. The packets are not of the Gaussian type with -r2 dependence but, instead, their shape is determined by -r with -1/2<μ<1/2. A very close quantum-classical correspondence is also shown, i.e., the well localized states travel along suitable classical trajectories.
Christiansen, Ove
2012-05-21
This perspective addresses selected recent developments in the theoretical calculation of vibrational spectra, energies, wave functions and properties. The theoretical foundation and recently developed computational protocols for constructing hierarchies of vibrational Hamiltonian operators are reviewed. A many-mode second quantization (SQ) formulation is discussed prior to the discussion of anharmonic wave functions. Emphasis is put on vibrational self-consistent field (VSCF) based methods and in particular vibrational coupled cluster (VCC) theory. Other issues are also reviewed briefly, such as inclusion of thermal effects, response theoretical calculation of spectra, and the difficulty in treating dense spectra.
Pietrzak, Robert H.; Goldstein, Risë B.; Southwick, Steven M.; Grant, Bridget F.
2010-01-01
The present study used data from the Wave 2 National Epidemiologic Survey on Alcohol and Related Conditions (n=34,653) to examine lifetime Axis I psychiatric comorbidity of posttraumatic stress disorder (PTSD) in a nationally representative sample of U.S. adults. Lifetime prevalences±standard errors of PTSD and partial PTSD were 6.4%±0.18 and 6.6%±0.18, respectively. Rates of PTSD and partial PTSD were higher among women (8.6%±0.26 and 8.6%±0.26) than men (4.1%±0.19 and 4.5%±0.21). Respondents with both PTSD and partial PTSD most commonly reported unexpected death of someone close, serious illness or injury to someone close, and sexual assault as their worst stressful experiences. PTSD and partial PTSD were associated with elevated lifetime rates of mood, anxiety, and substance use disorders, and suicide attempts. Respondents with partial PTSD generally had intermediate odds of comorbid Axis I disorders and psychosocial impairment relative to trauma controls and full PTSD. PMID:21168991
Nagase, Satoshi; Tanaka, Masamichi; Morita, Hiroshi; Nakagawa, Koji; Wada, Tadashi; Murakami, Masato; Nishii, Nobuhiro; Nakamura, Kazufumi; Ito, Hiroshi; Ohe, Tohru; Kusano, Kengo F
2017-01-01
Background: Brugada syndrome (BrS) is characterized by J-point or ST-segment elevation on electrocardiograms (ECGs) and increased risk of ventricular fibrillation (VF). In BrS, epicardial depolarization abnormality with delayed potential on the right ventricular outflow tract is reportedly the predominant mechanism underlying VF. Yet VF occurrence is also associated with early repolarization (ER) pattern in the inferolateral ECG leads, which may represent the inferior and/or left lateral ventricular myocardium. The aim of this study was to examine epicardial electrograms recorded directly at the left ventricle (LV) in BrS patients after VF episodes. Methods: In 12 BrS patients who had experienced VF episodes and 17 control subjects, a multipolar catheter was introduced into the left lateral coronary vein for unipolar and bipolar electrogram recordings at the LV epicardium. Both inferior and lateral ER patterns on ECG were observed in three BrS patients and six control subjects. Results: In the epicardium, prominent J waves were detected using unipolar recording, and potentials after the QRS complex were detected using bipolar recording in three of the 12 BrS patients. These three patients also showed both inferior and lateral ER patterns on ECG. Neither prominent J waves nor potentials after the QRS complex were recorded at the endocardium of the LV in any of these three patients; nor were they seen at the epicardium in any of the control subjects. These features were accentuated on pilsicainide administration (n = 2) but diminished on constant atrial pacing (n = 3) and isoproterenol administration (n = 1). The J waves observed through unipolar recording coincided with the potentials after QRS complex observed through bipolar recording and with the inferolateral ER patterns on ECG. Conclusions: We recorded prominent J waves in unipolar electrogram and potentials after QRS complex in bipolar electrogram at the LV epicardium in BrS patients with global ER pattern
Nagase, Satoshi; Tanaka, Masamichi; Morita, Hiroshi; Nakagawa, Koji; Wada, Tadashi; Murakami, Masato; Nishii, Nobuhiro; Nakamura, Kazufumi; Ito, Hiroshi; Ohe, Tohru; Kusano, Kengo F.
2017-01-01
Background: Brugada syndrome (BrS) is characterized by J-point or ST-segment elevation on electrocardiograms (ECGs) and increased risk of ventricular fibrillation (VF). In BrS, epicardial depolarization abnormality with delayed potential on the right ventricular outflow tract is reportedly the predominant mechanism underlying VF. Yet VF occurrence is also associated with early repolarization (ER) pattern in the inferolateral ECG leads, which may represent the inferior and/or left lateral ventricular myocardium. The aim of this study was to examine epicardial electrograms recorded directly at the left ventricle (LV) in BrS patients after VF episodes. Methods: In 12 BrS patients who had experienced VF episodes and 17 control subjects, a multipolar catheter was introduced into the left lateral coronary vein for unipolar and bipolar electrogram recordings at the LV epicardium. Both inferior and lateral ER patterns on ECG were observed in three BrS patients and six control subjects. Results: In the epicardium, prominent J waves were detected using unipolar recording, and potentials after the QRS complex were detected using bipolar recording in three of the 12 BrS patients. These three patients also showed both inferior and lateral ER patterns on ECG. Neither prominent J waves nor potentials after the QRS complex were recorded at the endocardium of the LV in any of these three patients; nor were they seen at the epicardium in any of the control subjects. These features were accentuated on pilsicainide administration (n = 2) but diminished on constant atrial pacing (n = 3) and isoproterenol administration (n = 1). The J waves observed through unipolar recording coincided with the potentials after QRS complex observed through bipolar recording and with the inferolateral ER patterns on ECG. Conclusions: We recorded prominent J waves in unipolar electrogram and potentials after QRS complex in bipolar electrogram at the LV epicardium in BrS patients with global ER pattern
Román, V; Gyertyán, I; Sághy, K; Kiss, B; Szombathelyi, Zs
2013-03-01
Cariprazine (RGH-188) is a D₃-preferring dopamine D₃/D₂ receptor partial agonist antipsychotic candidate for the treatment of schizophrenia and bipolar mania. Substance abuse is a frequent comorbidity of both disorders and is associated with serious health issues. Based on preclinical efficacy, dopamine D₂ and D₃ receptor partial agonists and antagonists are assumed to have relapse-preventing potential in human cocaine addiction. We investigated the anti-abuse potential of cariprazine in cocaine self-administration paradigms. Aripiprazole and bifeprunox were used as comparators because of their pharmacological similarity to cariprazine. The effects of compounds on cocaine's rewarding effect were investigated in a continuous self-administration regimen. The relapse-preventing potential of drugs was studied in rats with a history of cocaine self-administration after a period of complete abstinence in a relapse to cocaine-seeking paradigm. Cariprazine, as well as aripiprazole and bifeprunox, were able to reduce the rewarding effect of cocaine (minimum effective doses were 0.17, 1, and 0.1 mg/kg, respectively) and attenuated relapse to cocaine seeking with half maximal effective dose [ED₅₀] values of 0.2, 4.2, and 0.17 mg/kg, respectively. These results may predict a relapse-preventing action for cariprazine in humans in addition to its already established antipsychotic and antimanic efficacy.
Kuehr, Marietta; Wolfgarten, Matthias; Stoelzle, Marco; Leutner, Claudia; Hoeller, Tobias; Schrading, Simone; Kuhl, Christiane; Schild, Hans; Kuhn, Walther; Braun, Michael
2011-11-15
Purpose: Accelerated partial breast irradiation (APBI) after breast-conserving therapy is currently under investigation in prospective randomized studies. Multifocality and multicentricity are exclusion criteria for APBI. Preoperative breast magnetic resonance imaging (MRI) can detect ipsilateral and contralateral invasive tumor foci or ductal carcinoma in situ in addition to conventional diagnostic methods (clinical examination, mammography, and ultrasonography). The objective of this retrospective study was to evaluate the impact of preoperative MRI on patient selection for APBI. Methods and Materials: From 2002 to 2007, a total of 579 consecutive, nonselected patients with newly diagnosed early-stage breast cancer received preoperative breast MRI in addition to conventional imaging studies at the Bonn University Breast Cancer Center. In retrospect, 113 patients would have met the criteria for APBI using conventional imaging workup (clinical tumor size {<=}3 cm; negative axillary lymph node status; unifocal disease; no evidence of distant metastases; no invasive lobular carcinoma, ductal and lobular carcinoma in situ, or Paget's disease). We analyzed the amount of additional ipsilateral and contralateral tumor foci detected by MRI. Results: MRI detected additional tumor foci in 8.8% of patients eligible for APBI (11 tumor foci in 10 of 113 patients), either ipsilateral (n = 7, 6.2%) or contralateral (n = 4, 3.5%). In 1 patient, MRI helped detect additional tumor focus both ipsilaterally and contralaterally. Conclusions: Preoperative breast MRI is able to identify additional tumor foci in a clinically relevant number of cases in this highly selected group of patients with low-risk disease and may be useful in selecting patients for APBI.
Pietrzak, Robert H.; Goldstein, Risë B.; Southwick, Steven M.; Grant, Bridget F.
2011-01-01
Objectives To present findings on the prevalence, correlates, and psychiatric comorbidity of DSM-IV posttraumatic stress disorder (PTSD) and partial PTSD in a nationally representative sample of U.S. older adults. Design, Setting, and Participants Face-to-face interviews with 9,463 adults aged 60 years and older in the Wave 2 National Epidemiologic Survey on Alcohol and Related Conditions. Measurements Sociodemographic correlates, worst stressful experiences, comorbid lifetime mood, anxiety, substance use, and personality disorders, psychosocial functioning, and suicide attempts. Results Lifetime prevalences±standard errors of PTSD and partial PTSD were 4.5%±0.25 and 5.5%±0.27, respectively. Rates were higher in women (5.7%±0.37 and 6.5%±0.39) than men (3.1%±0.31 and 4.3%±0.37). Older adults with PTSD most frequently identified unexpected death of someone close, serious illness or injury to someone close, and own serious or life-threatening illness as their worst stressful events. Older adults exposed to trauma but without full or partial PTSD and respondents with partial PTSD most often identified unexpected death of someone close, serious illness or injury to someone close, and indirect experience of 9/11 as their worst events. PTSD was associated with elevated odds of lifetime mood, anxiety, drug use, and borderline and narcissistic personality disorders, and decreased psychosocial functioning. Partial PTSD was associated with elevated odds of mood, anxiety, and narcissistic and schizotypal personality disorders, and poorer psychosocial functioning relative to older adults exposed to trauma but without full or partial PTSD. Conclusions PTSD among older adults in the United States is slightly more prevalent than previously reported and associated with considerable psychiatric comorbidity and psychosocial dysfunction. Partial PTSD is associated with significant psychiatric comorbidity, particularly with mood and other anxiety disorders. PMID:22522959
Focused tandem shock waves in water and their potential application in cancer treatment
NASA Astrophysics Data System (ADS)
Lukes, P.; Sunka, P.; Hoffer, P.; Stelmashuk, V.; Pouckova, P.; Zadinova, M.; Zeman, J.; Dibdiak, L.; Kolarova, H.; Tomankova, K.; Binder, S.; Benes, J.
2014-01-01
The generator of two focused successive (tandem) shock waves (FTSW) in water produced by underwater multichannel electrical discharges at two composite electrodes, with a time delay between the first and second shock waves of 10 s, was developed. It produces, at the focus, a strong shock wave with a peak positive pressure of up to 80 MPa, followed by a tensile wave with a peak negative pressure of up to MPa, thus generating at the focus a large amount of cavitation. Biological effects of FTSW were demonstrated in vitro on hemolysis of erythrocytes and cell viability of human acute lymphoblastic leukemia cells as well as on tumor growth delay ex vivo and in vivo experiments performed with B16 melanoma, T-lymphoma, and R5-28 sarcoma cell lines. It was demonstrated in vivo that FTSW can enhance antitumor effects of chemotherapeutic drugs, such as cisplatin, most likely due to increased permeability of the membrane of cancer cells induced by FTSW. Synergetic cytotoxicity of FTSW with sonosensitive porphyrin-based drug Photosan on tumor growth was observed, possibly due to the cavitation-induced sonodynamic effect of FTSW.
ERIC Educational Resources Information Center
Li, Ying-Han; Tseng, Chao-Yuan; Tsai, Arthur Chih-Hsin; Huang, Andrew Chih-Wei; Lin, Wei-Lun
2016-01-01
Contemporary understanding of brain functions provides a way to probe into the mystery of creativity. However, the prior evidence regarding the relationship between creativity and brain wave patterns reveals inconsistent conclusions. One possible reason might be that the means of selecting creative individuals in the past has varied in each study.…
The Consequences of Alfven Waves and Parallel Potential Drops in the Auroral Zone
NASA Technical Reports Server (NTRS)
Schriver, David
2003-01-01
The goal of this research is to examine the causes of field-aligned plasma acceleration in the auroral zone using satellite data and numerical simulations. A primary question to be addressed is what causes the field-aligned acceleration of electrons (leading to precipitation) and ions (leading to upwelling ions) in the auroral zone. Data from the Fast Auroral SnapshoT (FAST) and Polar satellites is used when the two satellites are in approximate magnetic conjunction and are in the auroral region. FAST is at relatively low altitudes and samples plasma in the midst of the auroral acceleration region while Polar is at much higher altitudes and can measure plasmas and waves propagating towards the Earth. Polar can determine the sources of energy streaming earthward from the magnetotail, either in the form of field-aligned currents, electromagnetic waves or kinetic particle energy, that ultimately leads to the acceleration of plasma in the auroral zone. After identifying and examining several events, numerical simulations are run that bridges the spatial region between the two satellites. The code is a one-dimensional, long system length particle in cell simulation that has been developed to model the auroral region. A main goal of this research project is to include Alfven waves in the simulation to examine how these waves can accelerate plasma in the auroral zone.
ERIC Educational Resources Information Center
Li, Ying-Han; Tseng, Chao-Yuan; Tsai, Arthur Chih-Hsin; Huang, Andrew Chih-Wei; Lin, Wei-Lun
2016-01-01
Contemporary understanding of brain functions provides a way to probe into the mystery of creativity. However, the prior evidence regarding the relationship between creativity and brain wave patterns reveals inconsistent conclusions. One possible reason might be that the means of selecting creative individuals in the past has varied in each study.…
Perschall, Markus; Drevet, Jean Baptiste; Schenkel, Torsten; Oertel, Herbert
2012-09-01
This article describes the numerical fluid-structure interaction (FSI) validation of a new pumping concept and the possibility for application of a further developed type, as an implantable ventricular assist device (VAD). The novel principle of the so-called progressive wave pump is based on the interaction of an elastic membrane actuated by forced excitation with a surrounding fluid and the pump housing. By applying forced vibrations to one end of the membrane, a transversal wave builds up and progresses to the far end generating both a positive pressure gradient and flow rate. Among others, two axisymmetric geometrical configurations are possible, namely the discoidal and the tubular design. The first one has been built as a physical prototype and is experimentally investigated. In addition, a corresponding numerical FSI model is set up and validated against the experimental findings. Based on this validated numerical method, further numerical investigations are conducted focusing on the development of a tubular progressive wave pump concept with regard to its potential for application as a VAD in the future. To address VAD-relevant issues such as size, hydraulic performance, and blood trauma, corresponding numerical simulations involving macroscopic blood trauma models have been performed. Although being still in an early phase of development, the results are promising and indicate that the wave pump concept in its present state is feasible and can be further developed and investigated as a new type of blood pump.
NASA Astrophysics Data System (ADS)
Mijarez, Rito; Gaydecki, Patrick
2013-05-01
An automatic guided wave pulse position modulation system, using steel tubes as the communication channel, for detecting flooding in the hollow sub-sea structures of newly built offshore oilrigs is presented. Underwater close visual inspections (CVI) are normally conducted during swim-round surveys in pre-selected areas or areas suspected of damage. An acceptable alternative to CVI is a non-destructive testing (NDT) technique called flood member detection (FMD). Usually, this NDT technique employs ultrasound or x-rays to detect the presence of seawater in the tubular structures, requiring divers or remote operating vehicles (ROVs). The field-proven FMD technique, integrated within the concept of structural health monitoring, offers an alternative to these traditional inspection methods. The system employs two smart sensors and modulators, which transmit 40 kHz guided wave pulses, and a digital signal processing demodulator, which performs automatic detection of guided wave energy packets. Experiments were performed in dry conditions, inside and outside the laboratory; in the former using a steel tube 1.5 m×0.27 m×2 mm, and in the latter using a tubular steel heliport structure approximately 15 m×15 m in area and the base deck of an oilrig under construction. Results confirm that, although there was significant dispersion of the transmitted pulses, the system successfully distinguished automatically guided wave encoded information that could potentially be used in sub-sea oilrigs.
Burgermeister, Elke; Schnoebelen, Astride; Flament, Angele; Benz, Jörg; Stihle, Martine; Gsell, Bernard; Rufer, Arne; Ruf, Armin; Kuhn, Bernd; Märki, Hans Peter; Mizrahi, Jacques; Sebokova, Elena; Niesor, Eric; Meyer, Markus
2006-04-01
Partial agonists of peroxisome proliferator-activated receptor-gamma (PPARgamma), also termed selective PPARgamma modulators, are expected to uncouple insulin sensitization from triglyceride (TG) storage in patients with type 2 diabetes mellitus. These agents shall thus avoid adverse effects, such as body weight gain, exerted by full agonists such as thiazolidinediones. In this context, we describe the identification and characterization of the isoquinoline derivative PA-082, a prototype of a novel class of non-thiazolidinedione partial PPARgamma ligands. In a cocrystal with PPARgamma it was bound within the ligand-binding pocket without direct contact to helix 12. The compound displayed partial agonism in biochemical and cell-based transactivation assays and caused preferential recruitment of PPARgamma-coactivator-1alpha (PGC1alpha) to the receptor, a feature shared with other selective PPARgamma modulators. It antagonized rosiglitazone-driven transactivation and TG accumulation during de novo adipogenic differentiation of murine C3H10T1/2 mesenchymal stem cells. The latter effect was mimicked by overexpression of wild-type PGC1alpha but not its LXXLL-deficient mutant. Despite failing to promote TG loading, PA-082 induced mRNAs of genes encoding components of insulin signaling and adipogenic differentiation pathways. It potentiated glucose uptake and inhibited the negative cross-talk of TNFalpha on protein kinase B (AKT) phosphorylation in mature adipocytes and HepG2 human hepatoma cells. PGC1alpha is a key regulator of energy expenditure and down-regulated in diabetics. We thus propose that selective recruitment of PGC1alpha to favorable PPARgamma-target genes provides a possible molecular mechanism whereby partial PPARgamma agonists dissociate TG accumulation from insulin signaling.
Clarke, Alex. M.; Michie, Patricia T.; Glue, Leonard C. T.
1972-01-01
The experiments reported in this paper tested the hypothesis that the afferent potential elicited by a tendon tap in an isometrically recorded phasic stretch reflex can be detected in the surface EMG of normal humans when appropriate techniques are used. These techniques involved (1) training the subjects to relax mentally and physically so that the EMG was silent before and immediately after the diphasic MAP which reflects a highly synchronous discharge of afferent impulses from low threshold muscle stretch receptors after a tendon tap, and (2) using a data retrieval computer to summate stimulus-locked potentials in the EMG over a series of 16 samples using taps of uniform peak force and duration on the Achilles tendon to elicit the tendon jerk in the calf muscles. A discrete, diphasic potential (`A-wave') was recorded from EMG electrodes placed on the surface of the skin over the medial gastrocnemius muscle. The `A-wave' afferent potential had the opposite polarity to the corresponding efferent MAP. Under control conditions of relaxation the `A-wave' had a latency after the onset of the tap of 2 msec, the peak to peak amplitude was of the order of 5 μV and the duration was in the range of 6 to 10 msec. Further experiments were conducted to show that the `A-wave' (1) was not an artefact of the instrumentation used, (2) had a threshold at low intensities of stimulation, and (3) could be reliably augmented by using a Jendrassik manoeuvre compared with the potential observed during control (relaxation) conditions. The results support the conclusion that the `A-wave' emanates from the pool of muscle spindles which discharges impulses along group Ia nerve fibres in response to the phasic stretch stimulus because the primary ending of the spindles is known to initiate the stretch reflex and the spindles can be sensitized by fusimotor impulses so that their threshold is lowered as a result of a Jendrassik manoeuvre. The finding has important implications for the
Singh, Swati; Mun, Hyeona; Lee, Sanghoon; Kim, Sung Wng; Baik, Seunghyun
2017-09-01
The self-propagating exothermic chemical reaction with transient thermovoltage, known as the thermopower wave, has received considerable attention recently. A greater peak voltage and specific power are still demanded, and materials with greater Seebeck coefficients have been previously investigated. However, this study employs an alternative mechanism of transient chemical potential gradient providing an unprecedentedly high peak voltage (maximum: 8 V; average: 2.3 V) and volume-specific power (maximum: 0.11 W mm(-3) ; average: 0.04 W mm(-3) ) using n-type single-crystalline Bi2 Te3 substrates. A mixture of nitrocellulose and sodium azide is used as a fuel, and ultraviolet photoelectron spectroscopy reveals a significant downshift in Fermi energy (≈5.09 eV) of the substrate by p-doping of the fuel. The induced electrical potential by thermopower waves has two distinct sources: the Seebeck effect and the transient chemical potential gradient. Surprisingly, the Seebeck effect contribution is less than 2.5% (≈201 mV) of the maximum peak voltage. The right combination of substrate, fuel doping, and anisotropic substrate geometry results in an order of magnitude greater transient chemical potential gradient (≈5.09 eV) upon rapid removal of fuel by exothermic chemical reaction propagation. The role of fuel doping and chemical potential gradient can be viewed as a key mechanism for enhanced heat to electric conversion performance. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Scattering of a matter-wave single soliton and a two-soliton molecule by an attractive potential
Al-Marzoug, S. M.; Al-Amoudi, S. M.; Al Khawaja, U.; Bahlouli, H.; Baizakov, B. B.
2011-02-15
Scattering of a matter-wave single soliton and two-soliton molecule incident on the modified Poeschl-Teller potential well has been studied by means of a collective coordinate approach and numerical simulations of the Gross-Pitaevskii equation. Despite the attractive nature of the potential we observe total reflection of solitons in particular ranges of parameters, which is the signature of quantum behavior displayed by the matter-wave soliton. For other particular sets of parameters unscathed transmission of solitons and molecules through the potential well has been identified. A specific feature of this process is that the soliton passing through the potential well overtakes the freely propagating counterpart; i.e., its mean position appears to have been advanced in time. An array of such potentials makes the 'time advance' effect even more pronounced, so that scattered solitons move well ahead of nonscattered ones, fully preserving their initial shape and velocity. A possible application of the obtained results is pointed out.
Mertens, Franz G; Cooper, Fred; Arévalo, Edward; Khare, Avinash; Saxena, Avadh; Bishop, A R
2016-09-01
We discuss the behavior of solitary wave solutions of the nonlinear Schrödinger equation (NLSE) as they interact with complex potentials, using a four-parameter variational approximation based on a dissipation functional formulation of the dynamics. We concentrate on spatially periodic potentials with the periods of the real and imaginary part being either the same or different. Our results for the time evolution of the collective coordinates of our variational ansatz are in good agreement with direct numerical simulation of the NLSE. We compare our method with a collective coordinate approach of Kominis and give examples where the two methods give qualitatively different answers. In our variational approach, we are able to give analytic results for the small oscillation frequency of the solitary wave oscillating parameters which agree with the numerical solution of the collective coordinate equations. We also verify that instabilities set in when the slope dp(t)/dv(t) becomes negative when plotted parametrically as a function of time, where p(t) is the momentum of the solitary wave and v(t) the velocity.
van Schie, Hein T; Bekkering, Harold
2007-05-07
Event-related brain potentials were used to study the neural mechanisms underlying goal-directed object use distinguishing between processes supporting immediate and final action goals during action planning and execution. Subjects performed a grasping and transportation task in which actions were cued either with the immediate action goal (the part of the object to grasp) or with the final action goal of the movement (the end position for transportation). Slow wave potentials dissociated between processes supporting immediate and final goals: reaching for the object was accompanied by the development of a parietal-occipital slow wave that peaked in congruency with the grasping event, whereas transport of the object towards the final goal location was found accompanied by slow wave components developing over left frontal regions with a peak towards the movement end. Source localization of cueing differences indicated activation centered around the parieto-occipital sulcus during reaching of the immediate action goal, followed by enhanced activation in the anterior prefrontal cortex during transport to the final action goal. These results suggest the existence of separate neural controllers for immediate and final action goals during the execution of goal-directed actions with objects.
Potential damage to DC superconducting magnets due to the high frequency electromagnetic waves
NASA Technical Reports Server (NTRS)
Gabriel, G. J.
1977-01-01
Experimental data are presented in support of the hypothesis that a dc superconducting magnet coil does not behave strictly as an inductor, but as a complicated electrodynamic device capable of supporting electromagnetic waves. Travel times of nanosecond pulses and evidence of sinusoidal standing waves were observed on a prototype four-layer solenoidal coil at room temperature. Ringing observed during switching transients appears as a sequence of multiple reflected square pulses whose durations are related to the layer lengths. With sinusoidal excitation of the coil, the voltage amplitude between a pair of points on the coil exhibits maxima at those frequencies such that the distance between these points is an odd multiple of half wavelength in free space. Evidence indicates that any disturbance, such as that resulting from switching or sudden fault, initiates multiple reflections between layers, thus raising the possibility for sufficiently high voltages to cause breakdown.
White, Alexander James; Tretiak, Sergei; Mozyrsky, Dima V.
2016-04-25
Accurate simulation of the non-adiabatic dynamics of molecules in excited electronic states is key to understanding molecular photo-physical processes. Here we present a novel method, based on a semiclassical approximation, that is as efficient as the commonly used mean field Ehrenfest or ad hoc surface hopping methods and properly accounts for interference and decoherence effects. This novel method is an extension of Heller's thawed Gaussian wave-packet dynamics that includes coupling between potential energy surfaces. By studying several standard test problems we demonstrate that the accuracy of the method can be systematically improved while maintaining high efficiency. The method is suitablemore » for investigating the role of quantum coherence in the non-adiabatic dynamics of many-atom molecules.« less
White, Alexander James; Tretiak, Sergei; Mozyrsky, Dima V.
2016-04-25
Accurate simulation of the non-adiabatic dynamics of molecules in excited electronic states is key to understanding molecular photo-physical processes. Here we present a novel method, based on a semiclassical approximation, that is as efficient as the commonly used mean field Ehrenfest or ad hoc surface hopping methods and properly accounts for interference and decoherence effects. This novel method is an extension of Heller's thawed Gaussian wave-packet dynamics that includes coupling between potential energy surfaces. By studying several standard test problems we demonstrate that the accuracy of the method can be systematically improved while maintaining high efficiency. The method is suitable for investigating the role of quantum coherence in the non-adiabatic dynamics of many-atom molecules.
NASA Astrophysics Data System (ADS)
Wilgeroth, J. M.; Nguyen, T.-T. N.; Proud, W. G.
2014-05-01
Injuries to the tympanic membrane (ear drum) are particularly common in individuals subjected to blast overpressure such as military personnel engaged in conflict. Here, the interaction between blast wave and reticulated foams of varying density and thickness has been investigated using shock tube apparatus. The degree of mitigation afforded by the foam samples is discussed in relation to an injury threshold which has been suggested by others for the tympanic membrane.
NASA Astrophysics Data System (ADS)
Narikawa, Tatsuya; Tagoshi, Hideyuki
2016-09-01
We discuss the potential of advanced ground-based gravitational wave detectors such as LIGO, Virgo, and KAGRA to detect generic deviations of gravitational waveforms from the predictions of general relativity. We use the parameterized post-Einsteinian formalism to characterize the deviations, and assess what magnitude of deviations are detectable by using an approximate decision scheme based on Bayesian statistics. We find that there exist detectable regions of the parameterized post-Einsteinian parameters for different binary masses from the observation of a single gravitational wave event. The regions are not excluded by currently existing binary pulsar observations for the parameterized post-Einsteinian parameters at higher post-Newtonian order. We also find that neglect of orbital eccentricity or tidal deformation effects do not cause a significant bias on the detectable region of generic deviations from general relativity.
Eruption cyclicity at silicic volcanoes potentially caused by magmatic gas waves
NASA Astrophysics Data System (ADS)
Michaut, Chloé; Ricard, Yanick; Bercovici, David; Sparks, R. Steve J.
2013-10-01
Eruptions at active silicic volcanoes are often cyclical. For example, at the Soufrière Hills volcano in Montserrat, Mount Pinatubo in the Philippines, and Sakurajima in Japan, episodes of intense activity alternate with repose intervals over periods between several hours and a day. Abrupt changes in eruption rates have been explained with the motion of a plug of magma that alternatively sticks or slides along the wall of the volcanic conduit. However, it is unclear how the static friction that prevents the plug from sliding is periodically overcome. Here we use two-phase flow equations to model a gas-rich, viscous magma ascending through a volcanic conduit. Our analyses indicate that magma compaction yields ascending waves comprised of low- and high-porosity bands. However, magma ascent to lower pressures also causes gas expansion. We find that the competition between magma compaction and gas expansion naturally selects pressurized gas waves with specific periods. At the surface, these waves can induce cyclical eruptive behaviour with periods between 1 and 100 hours, which compares well to the observations from Soufrière Hills, Mount Pinatubo and Sakurajima. We find that the period is insensitive to volcano structure, but increases weakly with magma viscosity. We conclude that observations of a shift to a longer eruption cycle imply an increase in magma viscosity and thereby enhanced volcanic hazard.
Wang, Yiting; Liu, Jia; Loizidou, Avgi; Bugeja, Luc A; Warner, Ross; Hawley, Bethan R; Cai, Zhiwei; Toye, Ashley M; Sheppard, David N; Li, Hongyu
2014-01-01
Background and Purpose Dysfunction of the cystic fibrosis transmembrane conductance regulator (CFTR) Cl− channel causes the genetic disease cystic fibrosis (CF). Towards the development of transformational drug therapies for CF, we investigated the channel function and action of CFTR potentiators on A561E, a CF mutation found frequently in Portugal. Like the most common CF mutation F508del, A561E causes a temperature-sensitive folding defect that prevents CFTR delivery to the cell membrane and is associated with severe disease. Experimental Approach Using baby hamster kidney cells expressing recombinant CFTR, we investigated CFTR expression by cell surface biotinylation, and function and pharmacology with the iodide efflux and patch-clamp techniques. Key Results Low temperature incubation delivered a small proportion of A561E-CFTR protein to the cell surface. Like F508del-CFTR, low temperature-rescued A561E-CFTR exhibited a severe gating defect characterized by brief channel openings separated by prolonged channel closures. A561E-CFTR also exhibited thermoinstability, losing function more quickly than F508del-CFTR in cell-free membrane patches and intact cells. Using the iodide efflux assay, CFTR potentiators, including genistein and the clinically approved small-molecule ivacaftor, partially restored function to A561E-CFTR. Interestingly, ivacaftor restored wild-type levels of channel activity (as measured by open probability) to single A561E- and F508del-CFTR Cl− channels. However, it accentuated the thermoinstability of both mutants in cell-free membrane patches. Conclusions and Implications Like F508del-CFTR, A561E-CFTR perturbs protein processing, thermostability and channel gating. CFTR potentiators partially restore channel function to low temperature-rescued A561E-CFTR. Transformational drug therapy for A561E-CFTR is likely to require CFTR correctors, CFTR potentiators and special attention to thermostability. PMID:24902474
Parameterization of the nuclear Hulthén potentials
Laha, U. Bhoi, J.
2016-01-15
Within the formalism of supersymmetry-inspired factorization method, a two-term nuclear Hulthén potential has been developed and parameterized to reproduce the nucleon–nucleon scattering phase shifts for P and D partial wave states.
NASA Astrophysics Data System (ADS)
Laming, J. Martin
2017-08-01
We investigate in more detail the origin of chromospheric Alfvén waves that give rise to the separation of ions and neutrals—the first ionization potential (FIP) effect—through the action of the ponderomotive force. In open field regions, we model the dependence of fractionation on the plasma upflow velocity through the chromosphere for both shear (or planar) and torsional Alfvén waves of photospheric origin. These differ mainly in their parametric coupling to slow mode waves. Shear Alfvén waves appear to reproduce observed fractionations for a wider range of model parameters and present less of a “fine-tuning” problem than do torsional waves. In closed field regions, we study the fractionations produced by Alfvén waves with photospheric and coronal origins. Waves with a coronal origin, at or close to resonance with the coronal loop, offer a significantly better match to observed abundances than do photospheric waves, with shear and torsional waves in such a case giving essentially indistinguishable fractionations. Such coronal waves are likely the result of a nanoflare coronal heating mechanism that, as well as heating coronal plasmas, releases Alfvén waves that can travel down to loop footpoints and cause FIP fractionation through the ponderomotive force as they reflect from the chromosphere back into the corona.
Simair, Altaf Ahmed; Qureshi, Abdul Sattar; Khushk, Imrana; Ali, Chaudhry Haider; Lashari, Safia; Bhutto, Muhammad Aqeel; Mangrio, Ghulam Sughra; Lu, Changrui
2017-01-01
Amylase is an industrially important enzyme and applied in many industrial processes such as saccharification of starchy materials, food, pharmaceutical, detergent, and textile industries. This research work deals with the optimization of fermentation conditions for α-amylase production from thermophilic bacterial strain Bacillus sp. BCC 01-50 and characterization of crude amylase. The time profile of bacterial growth and amylase production was investigated in synthetic medium and maximum enzyme titer was observed after 60 h. In addition, effects of different carbon sources were tested as a substrate for amylase production and molasses was found to be the best. Various organic and inorganic compounds, potassium nitrate, ammonium chloride, sodium nitrate, urea, yeast extract, tryptone, beef extract, and peptone, were used and beef extract was found to be the best among the nitrogen sources used. Temperature, pH, agitation speed, and size of inoculum were also optimized. Highest enzyme activity was obtained when the strain was cultured in molasses medium for 60 h in shaking incubator (150 rpm) at 50°C and pH 8. Crude amylase showed maximal activity at pH 9 and 65°C. Enzyme remained stable in alkaline pH range 9-10 and 60-70°C. Crude amylase showed great potential for its application in detergent industry and saccharification of starchy materials.
NASA Astrophysics Data System (ADS)
Zhang, Yu-Feng; Feng, Bin-Lu; Rui, Wen-Juan; Zhang, Xiang-Zhi
2015-07-01
With the help of a simple Lie algebra, an isospectral Lax pair, whose feature presents decomposition of element (1, 2) into a linear combination in the temporal Lax matrix, is introduced for which a new integrable hierarchy of evolution equations is obtained, whose Hamiltonian structure is also derived from the trace identity in which contains a constant γ to be determined. In the paper, we obtain a general formula for computing the constant γ. The reduced equations of the obtained hierarchy are the generalized nonlinear heat equation containing three-potential functions, the mKdV equation and a generalized linear KdV equation. The algebro-geometric solutions (also called finite band solutions) of the generalized nonlinear heat equation are obtained by the use of theory on algebraic curves. Finally, two kinds of gauge transformations of the spatial isospectral problem are produced. Supported by the Innovation Team of Jiangsu Province hosted by China University of Mining and Technology (2014) and the National Natural Science Foundation of China under Grant No. 11371361, the Fundamental Research Funds for the Central Universities (2013XK03) as well as the Natural Science Foundation of Shandong Province under Grant No. ZR2013AL016
Haigh, Jody J; Ema, Masatsugu; Haigh, Katharina; Gertsenstein, Marina; Greer, Peter; Rossant, Janet; Nagy, Andras; Wagner, Erwin F
2004-02-01
Relatively little is known about the modulators of the vascular endothelial growth factor A (VEGF-A)/Flk1 signaling cascade. To functionally characterize this pathway, VEGF-A stimulation of endothelial cells was performed. VEGF-A-mediated Flk1 activation resulted in increased translocation of the endogenous Fps/Fes cytoplasmic tyrosine kinase to the plasma membrane and increased tyrosine phosphorylation, suggesting a role for Fps/Fes in VEGF-A/Flk1 signaling events. Addition of a myristoylation consensus sequence to Fps/Fes resulted in VEGF-A-independent membrane localization of Fps/Fes in endothelial cells. Expression of the activated Fps/Fes protein in Flk1-deficient embryonic stem (ES) cells rescued their contribution to the developing vascular endothelium in vivo by using ES cell-derived chimeras. Activated Fps/Fes contributed to this rescue event by restoring the migratory potential to Flk1 null progenitors, which is required for movement of hemangioblasts from the primitive streak region into the yolk sac proper. Activated Fps/Fes in the presence of Flk1 increased the number of hemangioblast colonies in vitro and increased the number of mesodermal progenitors in vivo. These results suggest that Fps/Fes may act synergistically with Flk1 to modulate hemangioblast differentiation into the endothelium. We have also demonstrated that activated Fps/Fes causes hemangioma formation in vivo, independently of Flk1, as a result of increasing vascular progenitor density.
Qureshi, Abdul Sattar; Khushk, Imrana; Ali, Chaudhry Haider; Lashari, Safia; Bhutto, Muhammad Aqeel; Mangrio, Ghulam Sughra; Lu, Changrui
2017-01-01
Amylase is an industrially important enzyme and applied in many industrial processes such as saccharification of starchy materials, food, pharmaceutical, detergent, and textile industries. This research work deals with the optimization of fermentation conditions for α-amylase production from thermophilic bacterial strain Bacillus sp. BCC 01-50 and characterization of crude amylase. The time profile of bacterial growth and amylase production was investigated in synthetic medium and maximum enzyme titer was observed after 60 h. In addition, effects of different carbon sources were tested as a substrate for amylase production and molasses was found to be the best. Various organic and inorganic compounds, potassium nitrate, ammonium chloride, sodium nitrate, urea, yeast extract, tryptone, beef extract, and peptone, were used and beef extract was found to be the best among the nitrogen sources used. Temperature, pH, agitation speed, and size of inoculum were also optimized. Highest enzyme activity was obtained when the strain was cultured in molasses medium for 60 h in shaking incubator (150 rpm) at 50°C and pH 8. Crude amylase showed maximal activity at pH 9 and 65°C. Enzyme remained stable in alkaline pH range 9-10 and 60–70°C. Crude amylase showed great potential for its application in detergent industry and saccharification of starchy materials. PMID:28168200
Kim, In Gyu; Kim, Jin Sik; Lee, Jae Ha; Cho, Eun Wie
2014-12-01
Various mechanisms have been proposed to underlie the cellular activity of genistein, based on biological experiments and epidemiological studies. The present study demonstrated that genistein inhibited the expression of cytoplasmic nicotinamide adenine dinucleotide phosphate (NADP)‑dependent isocitrate dehydrogenase (cICDH), thus increasing levels of intracellular reactive oxygen species (ROS) in human promyeloid leukemia HL‑60 cells. In genistein‑treated cells, the cellular redox potential (GSH/GSSG) was significantly decreased. This decrease in redox potential was caused by significant downregulation of the cICDH gene, generating the reducing equivalents (NADPH) for maintenance of cellular redox potential and cellular ROS level, which may regulate cell growth and cell death. Genistein‑induced ROS partially induced rapid transition into the G2/M phase by upregulation of p21wap1/cip1 and apoptotic cell death. Treatment of cells with N‑acetylcysteine, a well‑known antioxidant (ROS scavenger), not only partially restored cell growth and inhibited cell cycle arrest in G2/M, but also prevented apoptotic cell death. By contrast, normal lymphocytes did not significantly progress into the G2/M phase and radiation‑induced cell death was inhibited by genistein treatment. Therefore, genistein and γ‑irradiation together synergistically cause cell death in leukemia cells, however, genistein has a radioprotective effect in normal human lymphocytes. In conclusion, it was suggested that genistein selectively functions, not as an antioxidant, but as a pro‑oxidant in HL‑60 cells. This property can increase ionizing radiation‑induced cell cycle arrest and sensitivity to apoptotic cell death in human promyeloid leukemia HL‑60 cells, but does not cause significant damage to normal cells.
Mohamadou, Alidou; Wamba, Etienne; Kofane, Timoleon C.; Doka, Serge Y.; Ekogo, Thierry B.
2011-08-15
We examine the generation of bright matter-wave solitons in the Gross-Pitaevskii equation describing Bose-Einstein condensates with a time-dependent complex potential, which is composed of a repulsive parabolic background potential and a gravitational field. By performing a modified lens-type transformation, an explicit expression for the growth rate of a purely growing modulational instability is presented and analyzed. We point out the effects of the gravitational field, as well as of the parameter related to the feeding or loss of atoms in the condensate, on the instability growth rate. It is evident from numerical simulations that the feeding with atoms and the magnetic trap have opposite effects on the dynamics of the system. It is shown that the feeding or loss parameter can be well used to control the instability domain. Our study shows that the gravitational field changes the condensate trail of the soliton trains during the propagation. We also perform a numerical analysis to solve the Gross-Pitaevskii equation with a time-dependent complicated potential. The numerical results on the effect of both the gravitational field and the parameter of feeding or loss of atoms in the condensate agree well with predictions of the linear stability analysis. Another result of the present work is the modification of the background wave function in the Thomas-Fermi approximation during the numerical simulations.
NASA Astrophysics Data System (ADS)
Jaimes-Nájera, Alfonso; Rosas-Ortiz, Oscar
2017-01-01
Some general properties of the wave functions of complex-valued potentials with real spectrum are studied. The main results are presented in a series of lemmas, corollaries and theorems that are satisfied by the zeros of the real and imaginary parts of the wave functions on the real line. In particular, it is shown that such zeros interlace so that the corresponding probability densities ρ(x) are never null. We find that the profile of the imaginary part VI(x) of a given complex-valued potential determines the number and distribution of the maxima and minima of the related probability densities. Our conjecture is that VI(x) must be continuous in R, and that its integral over all the real line must be equal to zero in order to get control on the distribution of the maxima and minima of ρ(x) . The applicability of these results is shown by solving the eigenvalue equation of different complex potentials, these last being either PT-symmetric or not invariant under the PT-transformation.
Arteyeva, Natalia V; Azarov, Jan E
2017-07-11
The aim of the study was to differentiate the effect of dispersion of repolarization (DOR) and action potential duration (APD) on T-wave parameters being considered as indices of DOR, namely, Tpeak-Tend interval, T-wave amplitude and T-wave area. T-wave was simulated in a wide physiological range of DOR and APD using a realistic rabbit model based on experimental data. A simplified mathematical formulation of T-wave formation was conducted. Both the simulations and the mathematical formulation showed that Tpeak-Tend interval and T-wave area are linearly proportional to DOR irrespectively of APD range, while T-wave amplitude is non-linearly proportional to DOR and inversely proportional to the minimal repolarization time, or minimal APD value. Tpeak-Tend interval and T-wave area are the most accurate DOR indices independent of APD. T-wave amplitude can be considered as an index of DOR when the level of APD is taken into account. Copyright © 2017 Elsevier Inc. All rights reserved.
Scattering States of l-Wave Schrödinger Equation with Modified Rosen—Morse Potential
NASA Astrophysics Data System (ADS)
Chen, Wen-Li; Shi, Yan-Wei; Wei, Gao-Feng
2016-08-01
Within a Pekeris-type approximation to the centrifugal term, we examine the approximately analytical scattering state solutions of the l-wave Schrödinger equation with the modified Rosen—Morse potential. The calculation formula of phase shifts is derived, and the corresponding bound state energy levels are also obtained from the poles of the scattering amplitude. Supported by the National Natural Science Foundation of China under Grant No. 11405128, and Natural Science Basic Research Plan in Shaanxi Province of China under Grant No. 15JK2093
NASA Technical Reports Server (NTRS)
Morino, Luigi; Bharadvaj, Bala K.; Freedman, Marvin I.; Tseng, Kadin
1988-01-01
The wave equation for an object in arbitrary motion is investigated analytically using a BEM approach, and practical applications to potential flows of compressible fluids around aircraft wings and helicopter rotors are considered. The treatment accounts for arbitrary combined rotational and translational motion of the reference frame and for the wake motion. The numerical implementation as a computer algorithm is demonstrated on problems with prescribed and free wakes, the former in compressible flows and the latter for incompressible flows; results are presented graphically and briefly characterized.
Kayen, R.; Moss, R.E.S.; Thompson, E.M.; Seed, R.B.; Cetin, K.O.; Der Kiureghian, A.; Tanaka, Y.; Tokimatsu, K.
2013-01-01
Shear-wave velocity (Vs) offers a means to determine the seismic resistance of soil to liquefaction by a fundamental soil property. This paper presents the results of an 11-year international project to gather new Vs site data and develop probabilistic correlations for seismic soil liquefaction occurrence. Toward that objective, shear-wave velocity test sites were identified, and measurements made for 301 new liquefaction field case histories in China, Japan, Taiwan, Greece, and the United States over a decade. The majority of these new case histories reoccupy those previously investigated by penetration testing. These new data are combined with previously published case histories to build a global catalog of 422 case histories of Vs liquefaction performance. Bayesian regression and structural reliability methods facilitate a probabilistic treatment of the Vs catalog for performance-based engineering applications. Where possible, uncertainties of the variables comprising both the seismic demand and the soil capacity were estimated and included in the analysis, resulting in greatly reduced overall model uncertainty relative to previous studies. The presented data set and probabilistic analysis also help resolve the ancillary issues of adjustment for soil fines content and magnitude scaling factors.
Trivedi, Disha; Jena, Prasant Kumar; Patel, Jignesh Kumar; Seshadri, Sriram
2013-06-01
The emergence of antibiotic resistance has increased the interest for finding new antimicrobials in the past decade. Probiotic Lactic acid bacteria producing antimicrobial proteins like bacteriocin can be excellent agents for development as novel therapeutic agents and complement to conventional antibiotic therapy. Uropathogenic Escherichia coli, most causative agent of Urinary tract infection, has developed resistance to various antibiotics. In the present investigation, antibacterial substance like bacteriocin (Bacteriocin DT24) produced by probiotic Lactobacillus brevis DT24 from vaginal sample of healthy Indian woman was partially purified and characterized. It was efficiently working against various pathogens, that is, Uropathogenic E. coli, Enterococcus faecium, Enterococcus faecalis and Staphylococcus aureus. The antimicrobial peptide was relatively heat resistant and also active over a broad range of pH 2-10. It has been partially purified by ammonium sulfate precipitation and gel filtration chromatography and checked on reverse-phase high-performance liquid chromatography. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of bacteriocin DT24 was approximately 7-kDa protein. The peptide is inactivated by proteolytic enzymes, trypsin and lipase but not when treated with catalase, α-amylase and pepsin. It showed bacteriostatic mode of action against uropathogenic E. coli. Such characteristics indicate that this bacteriocin-producing probiotic may be a potential candidate for alternative agents to control urinary tract infections and other pathogens.
NASA Astrophysics Data System (ADS)
Mahedi, Masrur
Aggregates derived from natural sources have been used traditionally as the pavement base materials. But in recent times, the extraction of these natural aggregates has become more labor intensive and costly due to resource depletion and environmental concerns. Thus, the uses of recycled aggregates as the supplementary of natural aggregates are increasing considerably in pavement construction. Use of recycled aggregates such as recycled crushed concrete (RCA) and recycled asphalt pavement (RAP) reduces the rate of natural resource depletion, construction debris and cost. Although recycled aggregates could be used as a viable alternative of conventional base materials, strength characteristics and product variability limit their utility to a great extent. Hence, their applicability is needed to be evaluated extensively based on strength, stiffness and cost factors. But for extensive evaluation, traditionally practiced test methods are proven to be unreasonable in terms of time, cost, reliability and applicability. On the other hand, rapid non-destructive methods have the potential to be less time consuming and inexpensive along with the low variability of test results; therefore improving the reliability of estimated performance of the pavement. In this research work, the experimental program was designed to assess the potential application of stress wave velocity method as a non-destructive test in evaluating recycled base materials. Different combinations of cement treated recycled concrete aggregate (RAP) and recycled crushed concrete (RCA) were used to evaluate the applicability of stress wave velocity method. It was found that, stress wave velocity method is excellent in characterizing the strength and stiffness properties of cement treated base materials. Statistical models, based on P-wave velocity were derived for predicting the modulus of elasticity and compressive strength of different combinations of cement treated RAP, Grade-1 and Grade-2 materials. Two
Cohen, C; Bergis, O E; Galli, F; Lochead, A W; Jegham, S; Biton, B; Leonardon, J; Avenet, P; Sgard, F; Besnard, F; Graham, D; Coste, A; Oblin, A; Curet, O; Voltz, C; Gardes, A; Caille, D; Perrault, G; George, P; Soubrie, P; Scatton, B
2003-07-01
(5aS,8S,10aR)-5a,6,9,10-Tetrahydro,7H,11H-8,10a-methanopyrido[2',3':5,6]pyrano[2,3-d]azepine (SSR591813) is a novel compound that binds with high affinity to the rat and human alpha4beta2 nicotinic acetylcholine receptor (nAChR) subtypes (Ki = 107 and 36 nM, respectively) and displays selectivity for the alpha4beta2 nAChR (Ki, human alpha3beta4 > 1000, alpha3beta2 = 116; alpha1beta1deltagamma > 6000 nM and rat alpha7 > 6000 nM). Electrophysiological experiments indicate that SSR591813 is a partial agonist at the human alpha4beta2 nAChR subtype (EC50 = 1.3 micro M, IA =19% compared with the full agonist 1,1-dimethyl-4-phenyl-piperazinium). In vivo findings from microdialysis and drug discrimination studies confirm the partial intrinsic activity of SSR591813. The drug increases dopamine release in the nucleus accumbens shell (30 mg/kg i.p.) and generalizes to nicotine or amphetamine (10-20 mg/kg i.p.) in rats, with an efficacy approximately 2-fold lower than that of nicotine. Pretreatment with SSR591813 (10 mg/kg i.p.) reduces the dopamine-releasing and discriminative effects of nicotine. SSR591813 shows activity in animal models of nicotine dependence at doses devoid of unwanted side effects typically observed with nicotine (hypothermia and cardiovascular effects). The compound (10 mg/kg i.p.) also prevents withdrawal signs precipitated by mecamylamine in nicotine-dependent rats and partially blocks the discriminative cue of an acute precipitated withdrawal. SSR591813 (20 mg/kg i.p.) reduces i.v. nicotine self-administration and antagonizes nicotine-induced behavioral sensitization in rats. The present results confirm important role for alpha4beta2 nAChRs in mediating nicotine dependence and suggest that SSR591813, a partial agonist at this particular nAChR subtype, may have therapeutic potential in the clinical management of smoking cessation.
NASA Astrophysics Data System (ADS)
Yagi, Kent
2013-01-01
Deci-Hertz Interferometer Gravitational Wave Observatory (DECIGO) Pathfinder (DPF) has an ability to detect gravitational waves (GWs) from galactic intermediate mass black hole binaries. If the signal is detected, it would be possible to determine parameters of the binary components. Furthermore, by using future space-borne GW interferometers, it would be possible to test alternative theories of gravity in the strong field regime. In this review paper, we first explain how the detectors like DPF and DECIGO/BBO work and discuss the expected event rates. Then, we review how the observed gravitational waveforms from precessing compact binaries with slightly eccentric orbits can be calculated both in general relativity and in alternative theories of gravity. For the latter, we focus on Brans-Dicke (BD) and massive gravity (MG) theories. After reviewing these theories, we show the results of the parameter estimation with DPF using the Fisher analysis. We also discuss a possible joint search of DPF and ground-based interferometers. Then, we show the results of testing alternative theories of gravity using future space-borne interferometers. DECIGO/BBO would be able to place 4-5 orders of magnitude stronger constraint on BD theory than the solar system experiment. This is still 1-2 orders of magnitude stronger than the future solar system mission such as ASTROD I. On the other hand, LISA should be able to put four orders of magnitude more stringent constraint on the mass of the graviton than the current solar system bound. DPF may be able to place comparable constraint on the MG theories as the solar system bound. We also discuss the prospects of using eLISA and ASTROD-GW in testing alternative theories of gravity. The bounds using eLISA are similar to the LISA ones, but ASTROD-GW performs the best in constraining MG theories among all the GW detectors considered in this paper.
NASA Astrophysics Data System (ADS)
Medvinsky, M.; Tsynkov, S.; Turkel, E.
2013-06-01
The method of difference potentials generalizes the method of Calderon's operators from PDEs to arbitrary difference equations and systems. It offers several key advantages, such as the capability of handling boundaries/interfaces that are not aligned with the discretization grid, variable coefficients, and nonstandard boundary conditions. In doing so, the complexity of the algorithm remains comparable to that of an ordinary finite difference scheme on a regular structured grid. Previously, we have applied the method of difference potentials to solving several variable coefficient interior Helmholtz problems with fourth and sixth order accuracy. We have employed compact finite difference schemes as a core discretization methodology. Those schemes enable high order accuracy on narrow stencils and hence require only as many boundary conditions as needed for the underlying differential equation itself. Numerical experiments corroborate the high order accuracy of our method for variable coefficients, regular grids, and non-conforming boundaries. In the current paper, we extend the previously developed methodology to exterior problems. We present a complete theoretical analysis of the algorithm, as well as the results of a series of numerical simulations. Specifically, we study the scattering of time-harmonic waves about smooth shapes, subject to various boundary conditions. We also solve the transmission/scattering problems, in which not only do the waves scatter off a given shape but also propagate through the interface and travel across the heterogeneous medium inside. In all the cases, our methodology guarantees high order accuracy for regular grids and non-conforming boundaries and interfaces.
NASA Astrophysics Data System (ADS)
Askari, E.; Daneshmand, F.; Amabili, M.
2011-10-01
Internal bodies (baffles) are used as damping devices to suppress the fluid sloshing motion in fluid-structure interaction systems. An analytical method is developed in the present article to investigate the effects of a rigid internal body on bulging and sloshing frequencies and modes of a cylindrical container partially filled with a fluid. The internal body is a thin-walled and open-ended cylindrical shell that is coaxially and partially submerged inside the container. The interaction between the fluid and the structure is taken into account to calculate the sloshing and bulging frequencies and modes of the coupled system using the Rayleigh quotient, Ritz expansion and Galerkin method. It is shown that the present formulation is an appropriate and new approach to tackle the problem with good accuracy. The effects of fluid level, number of nodal diameters, internal body radius and submergence ratio on the dynamic characteristics of the coupled system are also investigated.
Zhang Shichang
2010-05-15
Nonlinear model and simulation technique of the interaction and energy transfer between a fast wave and a large-orbit relativistic electron beam in a coaxial electrostatic wiggler are presented. Unlike the situations in a magnetostatic-wiggler free-electron laser (MWFEL) and in an electron cyclotron maser (ECM), the electrostatic potential of the electrons plays an important role and participates in the energy exchange between the wave and the electron beam. Compared to MWFEL and ECM, the coaxial electrostatic-wiggler configuration has a distinguishing peculiarity that besides the electron-beam's kinetic energy, its electrostatic potential energy can be effectively transferred to the fast wave. Simulation shows that wave could be amplified with ultrahigh gain by extracting both the kinetic energy and electrostatic potential energy of the electron beam.
NASA Astrophysics Data System (ADS)
Cristofani, Edison; Friederich, Fabian; Wohnsiedler, Sabine; Matheis, Carsten; Jonuscheit, Joachim; Vandewal, Marijke; Beigang, René
2014-03-01
The sub-terahertz (THz) frequency band has proved to be a noteworthy option for nondestructive testing (NDT) of nonmetal aeronautics materials. Composite structures or laminates can be inspected for foreign objects (water or debris), delaminations, debonds, etc., using sub-THz sensors during the manufacturing process or maintenance. Given the harmless radiation to the human body of this frequency band, no special security measures are needed for operation. Moreover, the frequency-modulated continuous-wave sensor used in this study offers a very light, compact, inexpensive, and high-performing solution. An automated two-dimensional scanner carrying three sensors partially covering the 70- to 320-GHz band is operated, using two complementary measurement approaches: conventional focused imaging, where focusing lenses are used; and synthetic aperture (SA) or unfocused wide-beam imaging, for which lenses are no longer needed. Conventional focused imagery offers finer spatial resolutions but imagery is depth-limited due to the beam waist effect, whereas SA measurements allow imaging of thicker samples with depth-independent but coarser spatial resolutions. The present work is a compendium of a much larger study and describes the key technical aspects of the proposed imaging techniques and reports on results obtained from human-made samples (A-sandwich, C-sandwich, solid laminates) which include diverse defects and damages typically encountered in aeronautics multilayered structures. We conclude with a grading of the achieved results in comparison with measurements performed by other NDT techniques on the same samples.
Fleckenstein, Johannes; Friton, Mara; Himmelreich, Heiko; Banzer, Winfried
2017-05-01
To examine the effects of a single administration of focused extracorporeal shock wave therapy on eccentric exercise-induced delayed-onset muscle soreness (DOMS). Three-arm randomized controlled study. University research center. Participants (N=46; 23 women) had a mean age of 29.0±3.0 years and a mean body mass index of 23.8±2.8kg/m(2). Participants were randomly allocated to verum- (energy flux density, .06-.09mJ/mm(2); pulse ratio per point, 200) or sham-focused extracorporeal shock wave therapy (no energy) at 7 equidistant points along the biceps muscle or no intervention. The primary outcome was the difference in pain intensity. Secondary outcomes included maximum isometric voluntary force (MIVF), pressure pain threshold (PPT), and impairment in daily life. Despite descriptive clinically meaningful differences, mixed-effects analysis (group × time) of changes to baseline did not reveal significant differences in the reduction of pain intensity between groups (F2,42=2.5, P=.094). MIVF was not significantly different between groups (F2,43=1.9, P=.159). PTT (F2,43=0.2, P=.854) and daily life impairment (F2,42=1.4, P=.248) were not significantly decreased over time, and there were no differences between groups in the post hoc analysis. DOMS is a common symptom in people participating in exercise, sports, or recreational physical activities. A single treatment with focused extracorporeal shock wave therapy causes clinically relevant effects in the relief of pain, increase in force, and improvement of pain-associated impairments of daily living. Still, results need to be cautiously interpreted because of the pilot character of this study. Focused extracorporeal shock wave therapy might present an option in the midterm recovery from DOMS (72h) and be an approach to enhance the return to play in athletes. Copyright © 2017. Published by Elsevier Inc.
NASA Astrophysics Data System (ADS)
Rudnick, Roberta L.; Jackson, Ian
1995-06-01
Ultrasonic compressional wave velocities measured at 1.0 GPa and room temperature are compared with calculated velocities (based on single-crystal data and modal mineralogy) for a suite of mafic granulite xenoliths from the Chudleigh volcanic province, north Queensland, Australia. The xenoliths have nearly constant major element compositions but widely variable modal mineralogy, reflecting recrystallization under variable pressure-temperature conditions at depth in the continental crust (20-45 km). They thus provide an excellent opportunity to investigate velocity variation with depth in a mafic lower crust. Measured P wave velocities, corrected for the decompression-induced breakdown of garnet, range from 6.9 to 7.6 km/sec and correlate with derivation depth. These velocities are 5-12% lower than the calculated velocities (7.5-8.0 km/sec), apparently as a result of grain boundary alteration as well as irreversible changes that occurred in the xenoliths during rapid decompression. Calculated P wave velocities are similar to those estimated by Furlong and Fountain (1986) and Sobolev and Babeyko (1989) for mafic granulites formed through basaltic underplating of the continental crust. Depending upon in situ temperature, P wave velocities in the deepest samples may be interpreted as crustal (e.g., 7.3-7.6 km/sec, if heat flow is high) or mantle (7.7-7.8 km/sec, in areas of low heat flow). The range of velocities in the xenolith suite is larger than predicted for a fully equilibrated underplated basaltic layer, highlighting the importance of kinetic effects in determining the ultimate velocity profile of magmatically underplated crust. Comparison of our results with seismic profiles illustrates that the lower crust rarely reaches such high velocities, suggesting quartz-bearing rocks (country rocks?) are present within magmatically underplated layers of the deep crust.
s-wave scattering for deep potentials with attractive tails falling off faster than -1/r{sup 2}
Mueller, Tim-Oliver; Kaiser, Alexander; Friedrich, Harald
2011-09-15
For potentials with attractive tails, as occur in typical atomic interactions, we present a simple formula for the s-wave phase shift {delta}{sub 0}. It exposes a universal dependence of {delta}{sub 0}(E) on the potential tail and the influence of effects specific to a given potential, which enter via the scattering length a, or equivalently, the noninteger part {Delta}{sub th} of the threshold quantum number n{sub th}. The formula accurately reproduces {delta}{sub 0}(E) from threshold up to the semiclassical regime, far beyond the validity of the effective-range expansion. We derive the tail functions occurring in the formula for {delta}{sub 0}(E) and demonstrate the validity of the formula for attractive potential tails proportional to 1/r{sup 6} or to 1/r{sup 4}, and also for a mixed potential tail consisting of a 1/r{sup 4} term together with a non-negligible 1/r{sup 6} contribution.
NASA Astrophysics Data System (ADS)
Afzali, R.; Fahimi, S.; Dehghan, M.
2017-05-01
By considering a s-wave Bardeen-Cooper-Schrieffer superconductor, as a many body system, subject to a weak constant external potential, U, using perturbed linearized Gorkov equations at zero temperature and calculating perturbed Green's functions up to the first approximation, we obtain the two-particle space-spin density matrix of the system. Then, we investigate the effect of the potential on bipartite entanglement (via concurrence) of electron spins of a Cooper pair and also quantum discord in terms of the potential and the relative distance of electrons of a Cooper pair, r. At some fixed values of r, concurrence is zero and does not change until U increases and receives to a special value. Specially, quantum entanglement length and quantum correlation length (in which quantum discord becomes zero) with respect to the potential are derived. We result that by increasing the potential, these lengths are increased. At higher values of U, quantum correlation length is not very sensitive to changes in U. Finally, the relation between these lengths is given.
Non-Gaussian wave packet dynamics in anharmonic potential: Cumulant expansion treatment
NASA Astrophysics Data System (ADS)
Toutounji, Mohamad
2015-03-01
This manuscript utilizes cumulant expansion as an alternative algebraic approach to evaluating integrals and solving a system of nonlinear differential equations for probing anharmonic dynamics in condensed phase systems using Morse oscillator. These integrals and differential equations become harder to solve as the anharmonicity of the system goes beyond that of Morse oscillator description. This algebraic approach becomes critically important in case of Morse oscillator as it tends to exhibit divergent dynamics and numerical uncertainties at low temperatures. The autocorrelation function is calculated algebraically and compared to the exact one for they match perfectly. It is also compared to the approximate autocorrelation function using the differential equations technique reported in Toutounji (2014) for weak and strong electron-phonon coupling cases. It is found that the present cumulant method is more efficient, and easier to use, than the exact expression. Deviation between the approximate autocorrelation function and the exact autocorrelation function starts to arise as the electron-phonon coupling strength increases. The autocorrelation function obtained using cumulants identically matches the exact autocorrelation function, thereby surpassing the approach presented in Toutounji (2014). The advantage of the present methodology is its applicability to various types of electron-phonon coupling cases. Additionally, the herein approach only uses algebraic techniques, thereby avoiding both the divergence integral and solving a set of linear first- and second-order partial differential equations as was done in previous work. Model calculations are presented to demonstrate the accuracy of the herein work.
Stress formulation in the all-electron full-potential linearized augmented plane wave method
NASA Astrophysics Data System (ADS)
Nagasako, Naoyuki; Oguchi, Tamio
2012-02-01
Stress formulation in the linearlized augmented plane wave (LAPW) method has been proposed in 2002 [1] as an extension of the force formulation in the LAPW method [2]. However, pressure calculations only for Al and Si were reported in Ref.[1] and even now stress calculations have not yet been fully established in the LAPW method. In order to make it possible to efficiently relax lattice shape and atomic positions simultaneously and to precisely evaluate the elastic constants in the LAPW method, we reformulate stress formula in the LAPW method with the Soler-Williams representation [3]. Validity of the formulation is tested by comparing the pressure obtained as the trace of stress tensor with that estimated from total energies for a wide variety of material systems. Results show that pressure is estimated within the accuracy of less than 0.1 GPa. Calculations of the shear elastic constant show that the shear components of the stress tensor are also precisely computed with the present formulation [4].[4pt] [1] T. Thonhauser et al., Solid State Commun. 124, 275 (2002).[0pt] [2] R. Yu et al., Phys. Rev. B 43, 6411 (1991).[0pt] [3] J. M. Soler and A. R. Williams, Phys. Rev. B 40, 1560 (1989).[0pt] [4] N. Nagasako and T. Oguchi, J. Phys. Soc. Jpn. 80, 024701 (2011).
Eberhardt, Thomas L; Lebow, Stan; Reed, Karen G
2012-02-01
A cellulose solvent system based on lithium chloride (LiCl) in N-methyl-2-pyrrolidinone (NMP) was used to assess the merits of partial dissolutions of coarsely ground wood samples. Alkaline Copper Quaternary (ACQ)-treated pine wood was of particular interest for treatment given the potential to generate a copper-rich stream apart from solid and/or liquid lignocellulosic feedstocks. Treatment with NMP alone gave yields of soluble materials that were higher than typical extractives contents thereby suggesting a limited degree of wood dissolution. Inclusion of LiCl, which disrupts hydrogen bonding, gave lower wood residue recoveries (i.e., higher dissolution) with higher LiCl concentration. Lower wood residue recoveries coincided with lower Klason lignin and hemicellulose-derived sugar contents in the wood residues. After treatment with 8% LiCl in NMP, subsequent filtration afforded 34% of the ACQ-treated sapwood as a wood residue retaining only 2% of the original copper. Pouring the filtrate over an excess of water resulted in the recovery of 30% of the solids and 50% of the copper together as a copper-enriched lignocellulosic precipitate. Results demonstrate a solvent system showing potential as a means to separate heavy metals from preservative-treated wood and to recover lignocellulosic feedstocks that may be suitable for use in a biorefinery. Published by Elsevier Ltd.
Dirbas, Frederick M; Jeffrey, Stefanie S; Goffinet, Don R
2004-12-01
Breast conservation therapy (BCT) is a safe, effective alternative to mastectomy for many women with newly diagnosed breast cancer. This approach involves local excision of the malignancy with tumor-free margins, followed by 5-7 weeks of external beam whole breast (WB) radiotherapy (XRT) to minimize the risk of an in-breast tumor recurrence (IBTR). Though clearly beneficial, the extended course of almost daily postoperative radiotherapy interrupts normal activities and lengthens care. Additional options are now available that shorten the radiotherapy treatment time to 1-5 days (accelerated) and focus an increased dose of radiation on just the breast tissue around the excision cavity (partial breast). Recent trials with accelerated, partial breast irradiation (APBI) have shown promise as a potential replacement to the longer, whole breast treatments for select women with early-stage breast cancer. Current APBI approaches include interstitial brachytherapy, intracavitary (balloon) brachytherapy, and accelerated external beam (3-D conformal) radiotherapy, all of which normally complete treatment over 5 days, while intraoperative radiotherapy (IORT) condenses the entire treatment into a single dose delivered immediately after tumor excision. Each approach has benefits and limitations. This study covers over 2 decades of clinical trials exploring APBI, discusses treatment variables that appear necessary for successful implementation of this new form of radiotherapy, compares and contrasts the various APBI approaches, and summarizes current and planned randomized trials that will shape if and how APBI is introduced into routine clinical care. Some of the more important outcome variables from these trials will be local toxicity, local and regional recurrence, and overall survival. If APBI options are ultimately demonstrated to be as safe and effective as current whole breast radiotherapy approaches, breast conservation may become an even more appealing choice, and the
2016-01-01
Elucidating the underlying mechanisms of fatal cardiac arrhythmias requires a tight integration of electrophysiological experiments, models, and theory. Existing models of transmembrane action potential (AP) are complex (resulting in over parameterization) and varied (leading to dissimilar predictions). Thus, simpler models are needed to elucidate the “minimal physiological requirements” to reproduce significant observable phenomena using as few parameters as possible. Moreover, models have been derived from experimental studies from a variety of species under a range of environmental conditions (for example, all existing rabbit AP models incorporate a formulation of the rapid sodium current, INa, based on 30 year old data from chick embryo cell aggregates). Here we develop a simple “parsimonious” rabbit AP model that is mathematically identifiable (i.e., not over parameterized) by combining a novel Hodgkin-Huxley formulation of INa with a phenomenological model of repolarization similar to the voltage dependent, time-independent rectifying outward potassium current (IK). The model was calibrated using the following experimental data sets measured from the same species (rabbit) under physiological conditions: dynamic current-voltage (I-V) relationships during the AP upstroke; rapid recovery of AP excitability during the relative refractory period; and steady-state INa inactivation via voltage clamp. Simulations reproduced several important “emergent” phenomena including cellular alternans at rates > 250 bpm as observed in rabbit myocytes, reentrant spiral waves as observed on the surface of the rabbit heart, and spiral wave breakup. Model variants were studied which elucidated the minimal requirements for alternans and spiral wave break up, namely the kinetics of INa inactivation and the non-linear rectification of IK.The simplicity of the model, and the fact that its parameters have physiological meaning, make it ideal for engendering generalizable
NASA Astrophysics Data System (ADS)
Ducharme, R.; da Paz, I. G.
2016-08-01
In two recent papers exact Hermite-Gaussian solutions to relativistic wave equations were obtained for both electromagnetic and particle beams. The solutions for particle beams correspond to those of the Schrödinger equation in the nonrelativistic limit. Here, it will be shown that each beam particle has additional 4-momentum resulting from transverse localization compared to a free particle traveling in the same direction as the beam with the same speed. This will be referred to as the quantum 4-potential term since it will be shown to play an analogous role in relativistic Hamiltonian quantum mechanics as the Bohm potential in the nonrelativistic quantum Hamilton-Jacobi equation. Low-order localization effects include orbital angular momentum, Gouy phase, and beam spreading. Toward a more systematic approach for calculating localization effects at all orders, it will be shown that both the electromagnetic and quantum 4-potentials couple into the canonical 4-momentum of a particle in a similar way. This offers the prospect that traditional methods used to calculate the affect of an electromagnetic field on a particle can now be adapted to take localization effects into account. The prospects for measuring higher order quantum 4-potential related effects experimentally are also discussed alongside some questions to challenge the quantum information and quantum field theorists.
L2 discretization of Sturmian wave functions for Coulomb-like potentials
NASA Astrophysics Data System (ADS)
Frapiccini, A. L.; Gonzalez, V. Y.; Randazzo, J. M.; Colavecchia, F. D.; Gasaneo, G.
In this work we introduce a method to construct Sturmian functions for general interaction potentials in two-body problems. We expand these Sturmians on a finite L2 space, using N Laguerre basis functions to obtain a discrete set of eigenvalues for positive and negative energies. Orthogonality and closure relations are thus rewritten for these expansions; completeness is achieved through increasing the basis size. We apply the method to the Coulomb and Herman and Skillman potential. We study the behavior of the functions obtained and their convergence for an overall range of energies. The Sturmian functions are applied to solve the Schrödinger equation for an active electron in a He-like system.
Nonlinear waves in repulsive media supported by spatially localized parity-time-symmetric potentials
NASA Astrophysics Data System (ADS)
Devassy, Lini; Jisha, Chandroth P.; Alberucci, Alessandro; Kuriakose, V. C.
2017-06-01
We study the existence, stability and dynamics of solitons in a PT-symmetric potential in the presence of a local defocusing nonlinearity. For the sake of concreteness, we refer to Bose-Einstein condensates, where defocusing nonlinearity stems from a repulsive inter-particle interaction. Two kinds of transverse profiles for the gain-loss mechanism, i.e., the imaginary part of the potential, are considered. Differently from the attractive inter-particle interaction, solitons exist only inside a narrow band of chemical potential and particle number. The existence region shrinks as the magnitude of the gain-loss is increased, with the soliton ceasing to exist above the linear exceptional point, that is, the point at which PT symmetry is broken. Using linear stability analysis together with full numerical simulations of the Gross-Pitaevskii equation, we show that solitons survive on temporal scales much longer than the diffusion time. For magnitude of gain-loss close to the exceptional point, stability depends on the transverse profile of the gain-loss mechanism and the magnitude of the nonlinear excitation.
Effects of the third-order dispersion on continuous waves in complex potentials
NASA Astrophysics Data System (ADS)
Liu, Bin; Li, Lu; Malomed, Boris A.
2017-06-01
A class of constant-amplitude (CA) solutions of the nonlinear Schrödinger equation with the third-order spatial dispersion (TOD) and complex potentials are considered. The system can be implemented in specially designed planar nonlinear optical waveguides carrying a distribution of local gain and loss elements, in a combination with a photonic-crystal structure. The complex potential is built as a solution of the inverse problem, which predicts the potential supporting a required phase-gradient structure of the CA state. It is shown that the diffraction of truncated CA states with a correct phase structure can be strongly suppressed. The main subject of the analysis is the modulational instability (MI) of the CA states. The results show that the TOD term tends to attenuate the MI. In particular, simulations demonstrate a phenomenon of weak stability, which occurs when the linear-stability analysis predicts small values of the MI growth rate. The stability of the zero state, which is a nontrivial issue in the framework of the present model, is studied too.
NASA Astrophysics Data System (ADS)
Park, Yongcheol; Yoo, Hyun Jae; Lee, Won Sang; Lee, Choon-Ki; Lee, Joohan; Park, Hadong; Kim, Jinseok; Kim, Yeadong
2015-12-01
Mt. Melbourne is a late Cenozoic intraplate volcano located ∼30 km northeast of Jang Bogo Station in Antarctica. The volcano is quiescent with fumarolic activity at the summit. To monitor volcanic activity and glacial movements near Jang Bogo Station, a seismic network was installed during the 2010-11 Antarctic summer field season. The network is maintained during the summer field season every year, and the number of stations has been increased. We used continuous seismic data recorded by the network and an Italian seismic station (TNV) at Mario Zucchelli Station to develop a 3-D P-wave velocity model for the Mt. Melbourne area based on the teleseismic P-wave tomographic method. The new 3-D model presented a relative velocity structure for the lower part of the crust and upper mantle between depths of 30 and 160 km and revealed the presence of two low-velocity anomalies beneath Mt. Melbourne and the Priestley Fault. The low-velocity anomaly beneath Mt. Melbourne may be caused by the edge flow of hot mantle material at the lithospheric step between the thick East Antarctic Craton and thin Ross Sea crust. The other low-velocity anomaly along the Priestley Fault may have been beneath Mt. Melbourne and moved to the southern tip of the Deep Freeze Range, where the crustal thickness is relatively thin. The anomaly was trapped on the fault line and laterally flowed along the fault line in the northwest direction.
Gozem, Samer; Gunina, Anastasia O.; Ichino, Takatoshi; ...
2015-10-28
The calculation of absolute total cross sections requires accurate wave functions of the photoelectron and of the initial and final states of the system. The essential information contained in the latter two can be condensed into a Dyson orbital. We employ correlated Dyson orbitals and test approximate treatments of the photoelectron wave function, that is, plane and Coulomb waves, by comparing computed and experimental photoionization and photodetachment spectra. We find that in anions, a plane wave treatment of the photoelectron provides a good description of photodetachment spectra. For photoionization of neutral atoms or molecules with one heavy atom, the photoelectronmore » wave function must be treated as a Coulomb wave to account for the interaction of the photoelectron with the +1 charge of the ionized core. For larger molecules, the best agreement with experiment is often achieved by using a Coulomb wave with a partial (effective) charge smaller than unity. This likely derives from the fact that the effective charge at the centroid of the Dyson orbital, which serves as the origin of the spherical wave expansion, is smaller than the total charge of a polyatomic cation. Finally, the results suggest that accurate molecular photoionization cross sections can be computed with a modified central potential model that accounts for the nonspherical charge distribution of the core by adjusting the charge in the center of the expansion.« less
NASA Astrophysics Data System (ADS)
Oberleithner, Kilian; Rukes, Lothar; Paschereit, Oliver; Soria, Julio
2014-11-01
We report on a number of experimental and theoretical investigations of shear flow instabilities in jet flows. In these studies, linear stability analysis is employed to the time-averaged flow taken from experiments, contrasting the ``classic'' stability approach that is based on a stationary base flow. The eigenmodes of the time-averaged flow are considered as models for the nonlinearly saturated state of the instability waves. The accuracy of these models is validated through a detailed comparison with experiments. In this talk we outline the potential and limitation of these flow models for convectively and globally unstable jet flows. The first author was supported by a fellowship within the Postdoc-Program of the German Academic Exchange Service (DAAD). The support of the Australian Research Council (ARC) and the German Research Foundation (DFG) is greatfully acknowledged.
Pilot-wave dynamics in a harmonic potential: Quantization and stability of circular orbits.
Labousse, M; Oza, A U; Perrard, S; Bush, J W M
2016-03-01
We present the results of a theoretical investigation of the dynamics of a droplet walking on a vibrating fluid bath under the influence of a harmonic potential. The walking droplet's horizontal motion is described by an integro-differential trajectory equation, which is found to admit steady orbital solutions. Predictions for the dependence of the orbital radius and frequency on the strength of the radial harmonic force field agree favorably with experimental data. The orbital quantization is rationalized through an analysis of the orbital solutions. The predicted dependence of the orbital stability on system parameters is compared with experimental data and the limitations of the model are discussed.
Pilot-wave dynamics in a harmonic potential: Quantization and stability of circular orbits
NASA Astrophysics Data System (ADS)
Labousse, M.; Oza, A. U.; Perrard, S.; Bush, J. W. M.
2016-03-01
We present the results of a theoretical investigation of the dynamics of a droplet walking on a vibrating fluid bath under the influence of a harmonic potential. The walking droplet's horizontal motion is described by an integro-differential trajectory equation, which is found to admit steady orbital solutions. Predictions for the dependence of the orbital radius and frequency on the strength of the radial harmonic force field agree favorably with experimental data. The orbital quantization is rationalized through an analysis of the orbital solutions. The predicted dependence of the orbital stability on system parameters is compared with experimental data and the limitations of the model are discussed.
Janusek, D; Kania, M; Zaczek, R; Zavala-Fernandez, H; Maniewski, R
2014-04-01
The presence of T wave alternans (TWA) in the surface ECG signals has been recognized as a marker of electrical instability, and is hypothesized to be related to patients at increased risk for ventricular arrhythmias. In this paper we present a TWA simulation study. The TWA phenomenon was simulated by changing the duration of the ventricular heart cells action potential. The magnitude was calculated in the surface ECG with the use of the time domain method. The spatially concordant TWA, where during one heart beat all ventricular cells display a short-duration action potential and during the next beat they exhibit a long-duration action potential, as well as the discordant TWA, where at least one region is out of phase, was simulated. The vectocardiographic representation was employed. The obtained results showed a high level of T-loop pattern and location disturbances connected to the discordant TWA simulation in contrast to the concordant one. This result may be explained by the spatial heterogeneity of the ventricular repolarization process, which could be higher for the discordant TWA than for the concordant TWA. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.
The potential impact of scatterometry on oceanography - A wave forecasting case
NASA Technical Reports Server (NTRS)
Cane, M. A.; Cardone, V. J.
1981-01-01
A series of observing system simulation experiments have been performed in order to assess the potential impact of marine surface wind data on numerical weather prediction. In addition to conventional data, the experiments simulated the time-continuous assimilation of remotely sensed marine surface wind or temperature sounding data. The wind data were fabricated directly for model grid points intercepted by a Seasat-1 scatterometer swath and were assimilated into the lowest active level (945 mb) of the model using a localized successive correction method. It is shown that Seasat wind data can greatly improve numerical weather forecasts due to better definition of specific features. The case of the QE II storm is examined.
He, Jun-Rong; Li, Hua-Mei
2011-06-01
A large family of analytical solitary wave solutions to the generalized nonautonomous cubic-quintic nonlinear Schrödinger equation with time- and space-dependent distributed coefficients and external potentials are obtained by using a similarity transformation technique. We use the cubic nonlinearity as an independent parameter function, where a simple procedure is established to obtain different classes of potentials and solutions. The solutions exist under certain conditions and impose constraints on the coefficients depicting dispersion, cubic and quintic nonlinearities, and gain (or loss). We investigate the space-quadratic potential, optical lattice potential, flying bird potential, and potential barrier (well). Some interesting periodic solitary wave solutions corresponding to these potentials are then studied. Also, properties of a few solutions and physical applications of interest to the field are discussed. Finally, the stability of the solitary wave solutions under slight disturbance of the constraint conditions and initial perturbation of white noise is discussed numerically; the results reveal that the solitary waves can propagate in a stable way under slight disturbance of the constraint conditions and the initial perturbation of white noise.
Wong, Kevin; Levi, Jessica R
2017-03-01
Evaluate the content and readability of health information regarding partial tonsillectomy. A web search was performed using the term partial tonsillectomy in Google, Yahoo!, and Bing. The first 50 websites from each search were evaluated using HONcode standards for quality and content. Readability was assessed using the Flesch-Kincaid Grade Level (FKGL), Flesch Reading Ease, Gunning-Fog Index, Coleman-Liau Index, Automated Readability Index, and SMOG score. The Freeman-Halton extension of Fisher's exact test was used to compare categorical differences between engines. Less than half of the websites mentioned patient eligibility criteria (43.3%), referenced peer-reviewed literature (43.3%), or provided a procedure description (46.7%). Twenty-two websites (14.7%) were unrelated to partial tonsillectomy, and over half contained advertisements (52%). These finding were consistent across search engines and search terms. The mean FKGL was 11.6 ± 0.11, Gunning-Fog Index was 15.1 ± 0.13, Coleman-Liau Index was 14.6 ± 0.11, ARI was 12.9 ± 0.13, and SMOG grade was 14.0 ± 0.1. All readability levels exceeded the abilities of the average American adult. Current online information regarding partial tonsillectomy may not provide adequate information and may be written at a level too difficult for the average adult reader.
Potential Spacecraft-to-Spacecraft Radio Observations with EJSM: Wave of the Future? (Invited)
NASA Astrophysics Data System (ADS)
Marouf, E. A.; Tortora, P.; Asmar, S. W.; Folkner, W. M.; Hinson, D.; Iess, L.; Linscott, I. R.; Lorenz, R. D.; Mueller-Wodarg, I. C.
2010-12-01
Future active radio observations of planetary and satellite atmospheres and surfaces could significantly benefit form the presence of two or more spacecraft in orbit around a target object. Traditionally, radio occultation and bistatic surface scattering experiments have been conducted using a single spacecraft operating in the Downlink (DL) configuration, with the spacecraft transmitting and at least one Earth-based station receiving. The configuration has the advantage of using powerful ground-based receivers for down-conversion, digitization, and digital recording of large bandwidth data for later off-line processing and analysis. It has the disadvantage of an available free-space signal-to-noise ratio (SNR) limited by the relatively small carrier power (10-20 W) a spacecraft can practically transmit. Recent technological advances in designing small-mass and small-power spacecraft-based digital receivers capable of on-board signal processing could open the door for significant performance improvement compared with the DL configuration. For example, with two spacecraft in orbit instead of one, the smaller distance D between the two spacecraft compared with the distance to Earth can boost achievable free-space SNR by one to three orders of magnitude, depending on D. In addition, richer variability in observation geometry can be captured using spacecraft-to-spacecraft (SC-to-SC) radio occultations and surface scattering. By their nature, traditional DL occultations are confined to the morning and evening terminators. Availability of on-board processing capability also opens the door for conducting Uplink (UL) occultation and bistatic observations, where very large power (> 20 kW) can be transmitted from an Earth-based station, potentially boasting achievable free-space SNR by orders of magnitude, comparable to the SC-to-SC case and much higher than the DL case. The Europa Jupiter System Mission (EJSM) will likely be the first planetary mission to benefit from the
NASA Astrophysics Data System (ADS)
Goldzak, Tamar; Gilary, Ido; Moiseyev, Nimrod
2012-05-01
We show here for a simple model system that the wavepacket dynamics in the interaction region can be described by a superposition of the non-Hermitian exponential divergent eigenfunctions of the physical Hamiltonian. We demonstrate how it is possible to obtain the complex eigenvalues and also the corresponding resonance eigenfunctions from the propagation of the wavepacket within the framework of the standard formalism of quantum mechanics. The general results demonstrated here for a simple model can lead to two different types of computational applications: (i) for systems where one can obtain the resonance energies and lifetimes as well as their corresponding eigenfunctions it is possible to study the evolution of the physical properties solely based on the initially populated resonance states without the need to propagate the wavepacket; (ii) for molecular systems where it is quite difficult to solve the non-Hermitian time-independent Schrödinger equation and obtain molecular resonance energies and functions. For this type of problem, the methods presented here enable one to evaluate the topology of complex potential energy surfaces from the wavepacket propagation and facilitate the study of the nuclear dynamics of ionizing molecular systems.
Transport and selective chaining of bidisperse particles in a travelling wave potential.
Tierno, Pietro; Straube, Arthur V
2016-05-01
We combine experiments, theory and numerical simulation to investigate the dynamics of a binary suspension of paramagnetic colloidal particles dispersed in water and transported above a stripe-patterned magnetic garnet film. The substrate generates a one-dimensional periodic energy landscape above its surface. The application of an elliptically polarized rotating magnetic field causes the landscape to translate, inducing direct transport of paramagnetic particles placed above the film. The ellipticity of the applied field can be used to control and tune the interparticle interactions, from net repulsive to net attractive. When considering particles of two distinct sizes, we find that, depending on their elevation above the surface of the magnetic substrate, the particles feel effectively different potentials, resulting in different mobilities. We exploit this feature to induce selective chaining for certain values of the applied field parameters. In particular, when driving two types of particles, we force only one type to condense into travelling parallel chains. These chains confine the movement of the other non-chaining particles within narrow colloidal channels. This phenomenon is explained by considering the balance of pairwise magnetic forces between the particles and their individual coupling with the travelling landscape.
NASA Astrophysics Data System (ADS)
Thompson, Ian
2010-11-01
In all direct reactions to probe the structure of exotic nuclei at FRIB, optical potentials will be needed in the entrance and exit channels. At high energies Glauber approximations may be useful, but a low energies (5 to 20 MeV/nucleon) other approaches are required. Recent work of the UNEDF project [1] has shown that reaction cross sections at these energies can be accounted for by calculating all inelastic and transfer channels reachable by one particle-hole transitions from the elastic channel. In this model space, we may also calculate the two-step dynamic polarization potential (DPP) that adds to the bare folded potential to form the complex optical potential. Our calculations of the DPP, however, show that its non-localities are very significant, as well as the partial-wave dependence of both its real and imaginary components. The Perey factors (the wave function ratio to that from an equivalent local potential) are more than 20% different from unity, especially for partial waves inside grazing. These factors combine to suggest a reexamination of the validity of local and L-independent fitted optical potentials, especially for capture reactions that are dominated by low partial waves. Prepared by LLNL under Contract DE-AC52-07NA27344. [1] G.P.A. Nobre, F.S. Dietrich, J.E. Escher, I.J. Thompson, M. Dupuis, J. Terasaki and J. Engel, submitted to Phys. Rev. Letts., 2010.
Odd and even partial waves of ηπ- and η‧π- in π- p →η (‧)π- p at 191 GeV / c
NASA Astrophysics Data System (ADS)
Adolph, C.; Akhunzyanov, R.; Alexeev, M. G.; Alexeev, G. D.; Amoroso, A.; Andrieux, V.; Anosov, V.; Austregesilo, A.; Badełek, B.; Balestra, F.; Barth, J.; Baum, G.; Beck, R.; Bedfer, Y.; Berlin, A.; Bernhard, J.; Bicker, K.; Bielert, E. R.; Bieling, J.; Birsa, R.; Bisplinghoff, J.; Bodlak, M.; Boer, M.; Bordalo, P.; Bradamante, F.; Braun, C.; Bressan, A.; Büchele, M.; Burtin, E.; Capozza, L.; Chiosso, M.; Chung, S. U.; Cicuttin, A.; Crespo, M. L.; Curiel, Q.; Dalla Torre, S.; Dasgupta, S. S.; Dasgupta, S.; Denisov, O. Yu.; Donskov, S. V.; Doshita, N.; Duic, V.; Dünnweber, W.; Dziewiecki, M.; Efremov, A.; Elia, C.; Eversheim, P. D.; Eyrich, W.; Faessler, M.; Ferrero, A.; Finger, M.; Finger, M.; Fischer, H.; Franco, C.; du Fresne von Hohenesche, N.; Friedrich, J. M.; Frolov, V.; Gautheron, F.; Gavrichtchouk, O. P.; Gerassimov, S.; Geyer, R.; Gnesi, I.; Gobbo, B.; Goertz, S.; Gorzellik, M.; Grabmüller, S.; Grasso, A.; Grube, B.; Grussenmeyer, T.; Guskov, A.; Haas, F.; von Harrach, D.; Hahne, D.; Hashimoto, R.; Heinsius, F. H.; Herrmann, F.; Hinterberger, F.; Höppner, Ch.; Horikawa, N.; d'Hose, N.; Huber, S.; Ishimoto, S.; Ivanov, A.; Ivanshin, Yu.; Iwata, T.; Jahn, R.; Jary, V.; Jasinski, P.; Jörg, P.; Joosten, R.; Kabuß, E.; Ketzer, B.; Khaustov, G. V.; Khokhlov, Yu. A.; Kisselev, Yu.; Klein, F.; Klimaszewski, K.; Koivuniemi, J. H.; Kolosov, V. N.; Kondo, K.; Königsmann, K.; Konorov, I.; Konstantinov, V. F.; Kotzinian, A. M.; Kouznetsov, O.; Krämer, M.; Kroumchtein, Z. V.; Kuchinski, N.; Kunne, F.; Kurek, K.; Kurjata, R. P.; Lednev, A. A.; Lehmann, A.; Levillain, M.; Levorato, S.; Lichtenstadt, J.; Maggiora, A.; Magnon, A.; Makke, N.; Mallot, G. K.; Marchand, C.; Martin, A.; Marzec, J.; Matousek, J.; Matsuda, H.; Matsuda, T.; Meshcheryakov, G.; Meyer, W.; Michigami, T.; Mikhailov, Yu. V.; Miyachi, Y.; Nagaytsev, A.; Nagel, T.; Nerling, F.; Neubert, S.; Neyret, D.; Novy, J.; Nowak, W.-D.; Nunes, A. S.; Olshevsky, A. G.; Orlov, I.; Ostrick, M.; Panknin, R.; Panzieri, D.; Parsamyan, B.; Paul, S.; Peshekhonov, D. V.; Platchkov, S.; Pochodzalla, J.; Polyakov, V. A.; Pretz, J.; Quaresma, M.; Quintans, C.; Ramos, S.; Regali, C.; Reicherz, G.; Rocco, E.; Rossiyskaya, N. S.; Ryabchikov, D. I.; Rychter, A.; Samoylenko, V. D.; Sandacz, A.; Sarkar, S.; Savin, I. A.; Sbrizzai, G.; Schiavon, P.; Schill, C.; Schlüter, T.; Schmidt, K.; Schmieden, H.; Schönning, K.; Schopferer, S.; Schott, M.; Shevchenko, O. Yu.; Silva, L.; Sinha, L.; Sirtl, S.; Slunecka, M.; Sosio, S.; Sozzi, F.; Srnka, A.; Steiger, L.; Stolarski, M.; Sulc, M.; Sulej, R.; Suzuki, H.; Szabelski, A.; Szameitat, T.; Sznajder, P.; Takekawa, S.; ter Wolbeek, J.; Tessaro, S.; Tessarotto, F.; Thibaud, F.; Uhl, S.; Uman, I.; Virius, M.; Wang, L.; Weisrock, T.; Wilfert, M.; Windmolders, R.; Wollny, H.; Zaremba, K.; Zavertyaev, M.; Zemlyanichkina, E.; Ziembicki, M.; Zink, A.
2015-01-01
Exclusive production of ηπ- and η‧π- has been studied with a 191 GeV / cπ- beam impinging on a hydrogen target at COMPASS (CERN). Partial-wave analyses reveal different odd/even angular momentum (L) characteristics in the inspected invariant mass range up to 3 GeV /c2. A striking similarity between the two systems is observed for the L = 2 , 4 , 6 intensities (scaled by kinematical factors) and the relative phases. The known resonances a2 (1320) and a4 (2040) are in line with this similarity. In contrast, a strong enhancement of η‧π- over ηπ- is found for the L = 1 , 3 , 5 waves, which carry non- q q bar quantum numbers. The L = 1 intensity peaks at 1.7 GeV /c2 in η‧π- and at 1.4 GeV /c2 in ηπ-, the corresponding phase motions with respect to L = 2 are different.
NASA Technical Reports Server (NTRS)
Dimofte, Florin
1993-01-01
Analysis of the waved journal bearing concept featuring a waved inner bearing diameter for use with a compressible lubricant (gas) is presented. The performance of generic waved bearings having either three or four waves is predicted for air lubricated bearings. Steady-state performance is discussed in terms of bearing load capacity, while the dynamic performance is discussed in terms of fluid film stability and dynamic coefficients. It was found that the bearing wave amplitude has an important influence on both the steady-state and the dynamic performance of the waved journal bearing. For a fixed eccentricity ratio, the bearing steady-state load capacity and direct dynamic stiffness coefficient increase as the wave amplitude increases.
NASA Technical Reports Server (NTRS)
Dimofte, Florin
1993-01-01
Analysis of the waved journal bearing concept featuring a waved inner bearing diameter for use with a compressible lubricant (gas) is presented. The performance of generic waved bearings having either three or four waves is predicted for air lubricated bearings. Steady-state performance is discussed in terms of bearing load capacity, while the dynamic performance is discussed in terms of fluid film stability and dynamic coefficients. It was found that the bearing wave amplitude has an important influence on both the steady-state and the dynamic performance of the waved journal bearing. For a fixed eccentricity ratio, the bearing steady-state load capacity and direct dynamic stiffness coefficient increase as the wave amplitude increases.
Lewalter, T; Schimpf, R; Kulik, D; Wolpert, C; Jung, W; Lüderitz, B
2000-04-01
Although bipolar sensing is recommended and desirable in patients with dual chamber pacemakers (DDD) and intermittent atrial fibrillation (AF) it is a clinical reality that some patients who are given unipolar atrial leads without a prior history of AF may develop intermittent AF during follow-up. It was therefore the purpose of this prospective study to compare the electrogram amplitudes of AF potentials with sinus rhythm P-wave potentials as a relevant factor for appropriate mode switching in dual chamber pacing with unipolar atrial sensing. Forty-two patients with dual chamber pacemakers, unipolar atrial leads and intermittent AF were studied. Aside from measuring the P-wave potential, it was possible in 14 patients (4 women, 10 men; mean age: 61.8 (+/- 13.3) years) additionally to document spontaneous AF electrogram potentials using pacemaker telemetry. A prospective survey study was performed including a 6 month follow-up period with an outpatient clinic visit every 2-3 weeks. The mean P-wave electrogram amplitude was 3.4 (+/- 1.8) mV (range: 1.4-7.4) compared with the mean amplitude during AF of 2.04 (+/- 1.26) mV (range: 0.8-5.2 mV) indicating a significant attenuation of 40% during AF (P < 0.0001). A linear correlation regression analysis revealed that there was a significant correlation between the P-wave and the AF amplitude (P < 0.0001), with a correlation coefficient of r = 0.867. Once it is known that a substantial reduction exists in electrogram amplitude, compared with the P wave electrogram potential, an estimate can be made of whether AF potentials will be sensed, if the programming of atrial sensitivity is congruent with the P-wave characteristics and the presence or absence of myopotential triggering.
NASA Astrophysics Data System (ADS)
Kengne, E.; Lakhssassi, A.; Liu, W. M.
2017-08-01
A lossless nonlinear L C transmission network is considered. With the use of the reductive perturbation method in the semidiscrete limit, we show that the dynamics of matter-wave solitons in the network can be modeled by a one-dimensional Gross-Pitaevskii (GP) equation with a time-dependent linear potential in the presence of a chemical potential. An explicit expression for the growth rate of a purely growing modulational instability (MI) is presented and analyzed. We find that the potential parameter of the GP equation of the system does not affect the different regions of the MI. Neglecting the chemical potential in the GP equation, we derive exact analytical solutions which describe the propagation of both bright and dark solitary waves on continuous-wave (cw) backgrounds. Using the found exact analytical solutions of the GP equation, we investigate numerically the transmission of both bright and dark solitary voltage signals in the network. Our numerical studies show that the amplitude of a bright solitary voltage signal and the depth of a dark solitary voltage signal as well as their width, their motion, and their behavior depend on (i) the propagation frequencies, (ii) the potential parameter, and (iii) the amplitude of the cw background. The GP equation derived in this paper with a time-dependent linear potential opens up different ideas that may be of considerable theoretical interest for the management of matter-wave solitons in nonlinear L C transmission networks.
Garina, N S; Erchenkov, V G; Vorontsov, D D; Semina, T K
2006-01-01
Amplitudes and peak latencies as functions of wave length and monochromatic light intensity were investigated for b-wave ERG and tectal evoked potentials (EP) in the dark-adapted carp (Cyprinus carpio L). It was found, that independently of light intensity b-wave action spectra had one maximum in the medium wave band, corresponding to rod sensitivity area. For tectal EP, similar action spectra with maximum in the middle-wave were seen at low light intensity only. The b-wave amplitude growth was significant for the whole band of light intensities, and these changes were accompanied with a slight decrease in peak latency (to 50-100 ms). Tectal EP amplitude increased when low-intensity light was changed for medium intensity light and did not considerably increase to brighter light stimuli. However, tectal EP time latency significantly decreased (to 100-200 ms) during light intensity increasing. This differences show that retinal rod system, which in responsible for ERG b-wave in darkness, is not a key factor in the generation of tectal EP.
NASA Astrophysics Data System (ADS)
Kengne, Emmanuel; Shehou, Abdourahman; Lakhssassi, Ahmed
2016-03-01
We investigate the dynamics of matter-wave solitons in the one-dimensional (1-D) Gross-Pitaevskii (GP) equation describing Bose-Einstein condensates (BECs) with time-dependent scattering length in varying trapping potentials with feeding/loss term. By performing a modified lens-type transformation, we reduce the GP equation into a classical nonlinear Schrödinger (NLS) equation with distributed coefficients and find its integrable condition. Under the integrable condition, we apply the generalized Jacobian elliptic function method (GJEFM) and present exact analytical solutions which describe the propagation of a bright and dark solitons in BECs. Their stability is examined using analytic method. The obtained exact solutions show that the amplitude of bright and dark solitons depends on the scattering length, while their motion and the total number of BEC atoms depend on the external trapping potential. Our results also shown that the loss of atoms can dominate the aggregation of atoms by the attractive interaction, and thus the peak density can decrease in time despite that the strength of the attractive interaction is increased.
NASA Astrophysics Data System (ADS)
Lu, Xian; Chu, Xinzhao; Fong, Weichun; Chen, Cao; Yu, Zhibin; Roberts, Brendan R.; McDonald, Adrian J.
2015-04-01
We report the first characterization of potential energy densities and vertical wave number spectra of Antarctic gravity waves (GWs) from 35 to 105 km, derived from Fe lidar temperature measurements at McMurdo (77.8°S, 166.7°E) in 2011-2013 winters. For GWs with periods of 2-10 h, the potential energy density per unit volume (Epv) decreases by 2 orders of magnitude from 35 to 105 km, while that per unit mass (Epm) increases from several to hundreds of J/kg. Epm increases with a mean scale height of 10.4 km in the Rayleigh region (35-65 km) and of 13.2 km in the Fe region (81-105 km), and of particular interest is the inferred severe dissipation in between (65-81 km). Overall, the vertical evolutions of Epv and Epm indicate considerable wave energy loss from the stratosphere to the lower thermosphere. The vertical wave number spectra exhibit power law forms for vertical wavelengths λz < 10 km. The mean spectral slope in the spectral range of 2-10 km is about -2.55 and -2.26 in the Rayleigh and Fe regions with standard deviations of 0.36 and 0.38, respectively. Large variations in the power spectral densities (PSDs) are seen for λz > 10 km in 35-60 km. PSDs increase by 1 order of magnitude from the stratosphere to the lower thermosphere. Using higher temporal resolution data to include 0.5-2 h waves increase Epm by 25-45% and increase PSDs of 2-5 km waves by a factor of 2 and of >10 km waves by less than 50%.
Zhong, Wei-Ping; Belić, Milivoj; Zhang, Yiqi
2015-02-09
Nonlinear Schrödinger equation with simple quadratic potential modulated by a spatially-varying diffraction coefficient is investigated theoretically. Second-order rogue wave breather solutions of the model are constructed by using the similarity transformation. A modal quantum number is introduced, useful for classifying and controlling the solutions. From the solutions obtained, the behavior of second order Kuznetsov-Ma breathers (KMBs), Akhmediev breathers (ABs), and Peregrine solitons is analyzed in particular, by selecting different modulation frequencies and quantum modal parameter. We show how to generate interesting second order breathers and related hybrid rogue waves. The emergence of true rogue waves - single giant waves that are generated in the interaction of KMBs, ABs, and Peregrine solitons - is explicitly displayed in our analytical solutions.
Giacomelli, S; Palmery, M; Romanelli, L; Cheng, C Y; Silvestrini, B
1998-01-01
The hallucinogenic effects of lysergic acid diethylamide (LSD) have mainly been attributed to the interaction of this drug with the serotoninergic system, but it seems more likely that they are the result of the complex interactions of the drug with both the serotoninergic and dopaminergic systems. The aim of the present study was to investigate the functional actions of LSD at dopaminergic receptors using prolactin secretion by primary cultures of rat pituitary cells as a model. LSD produced a dose-dependent inhibition of prolactin secretion in vitro with an IC50 at 1.7x10(-9) M. This action was antagonized by spiperone but not by SKF83566 or cyproheptadine, which indicates that LSD has a specific effect on D2 dopaminergic receptors. The maximum inhibition of prolactin secretion achieved by LSD was lower than that by dopamine (60% versus 80%). Moreover, the fact that LSD at 10(-8)-10(-6) M antagonized the inhibitory effect of dopamine (10(-7) M) and bromocriptine (10(-11) M) suggests that LSD acts as a partial agonist at D2 receptors on lactotrophs in vitro. Interestingly, LSD at 10(-13)-10(-10) M, the concentrations which are 10-1000-fold lower than those required to induce direct inhibition on pituitary prolactin secretion, potentiated the dopamine (10(-10)-2.5x10(-9) M)-mediated prolactin secretion by pituitary cells in vitro. These results suggest that LSD not only interacts with dopaminergic receptors but also has a unique capacity for modulating dopaminergic transmission. These findings may offer new insights into the hallucinogenic effect of LSD.
NASA Technical Reports Server (NTRS)
Title, A. M. (Inventor)
1978-01-01
A birefringent filter module comprises, in seriatum. (1) an entrance polarizer, (2) a first birefringent crystal responsive to optical energy exiting the entrance polarizer, (3) a partial polarizer responsive to optical energy exiting the first polarizer, (4) a second birefringent crystal responsive to optical energy exiting the partial polarizer, and (5) an exit polarizer. The first and second birefringent crystals have fast axes disposed + or -45 deg from the high transmitivity direction of the partial polarizer. Preferably, the second crystal has a length 1/2 that of the first crystal and the high transmitivity direction of the partial polarizer is nine times as great as the low transmitivity direction. To provide tuning, the polarizations of the energy entering the first crystal and leaving the second crystal are varied by either rotating the entrance and exit polarizers, or by sandwiching the entrance and exit polarizers between pairs of half wave plates that are rotated relative to the polarizers. A plurality of the filter modules may be cascaded.
NASA Astrophysics Data System (ADS)
Alexander, M. J.; Sherwood, S.; Mahoney, M. J.; Bui, P.
2003-12-01
Gravity waves are known to affect cloud formation via the temperature perturbations they cause, and these effects can be significant in conditions that are otherwise marginal for cloud formation. Cirrus clouds near the tropopause can form in the cold phases of gravity waves. The ER-2 aircraft observations during the CRYSTAL-FACE campaign provide a unique set for gravity wave analysis. For the first time, data from both the Microwave Temperature Profiler (MTP) and Meteorological Measurement System (MMS) were obtained together from the ER-2 platform, with flight paths near convection. Analyses of MTP and MMS data can be combined to provide the full set of gravity wave parameters needed to model their origin, propagation, and eventual fate. This wave analysis requires long, constant-level flight paths. First a wavelet analysis in horizontal wavenumber is performed along the flight path direction for measurements of temperature and horizontal wind. From this, the strongest wave modes are identified, and the vertical wavenumber estimated from the MTP data for these modes. Linear wave theory is then employed to compute the propagation directions and intrinsic frequencies for these strongest wave modes. The results of this analysis thus provide the full three-dimensional propagation characteristics for the dominant gravity wave modes in the data. We subsequently use these results to examine their role in cirrus cloud formation at lower altitudes, and compare the results to in situ measurements made from the WB-57F aircraft platform.
Discordant U waves in the setting of hyperkalaemia.
Chhabra, Lovely; Spodick, David H
2013-07-04
Physiological U wave genesis occurs likely secondary to either late repolarisation of Purkinje fibres, or late repolarisation of some myocardial cells and/or delayed after depolarisation of the ventricular wall occurring during ventricular filling. Hypokalaemia has a well-known association with pathological 'U wave' which actually combines with the T wave (TU complex) and results from slowing of phase 3 of the action potential with resultant electrical interaction between the three myocardial layers. U waves usually tend to disappear in the setting of hyperkalaemia. We report an unusual case where hyperkalaemia and discordant U waves coexisted. We believe that this may have occurred as a result of partial clinical adaptation of cardiac myocytes to the long-standing effects of hyperkalaemia as the patient had underlying history of chronic kidney disease. We also discuss the possible mechanisms of the U wave genesis and the importance of different U wave morphologies encountered in the real clinical practice.
Baczewski, Andrew David; Vikram, Melapudi; Shanker, Balasubramaniam; ...
2010-08-27
Diffusion, lossy wave, and Klein–Gordon equations find numerous applications in practical problems across a range of diverse disciplines. The temporal dependence of all three Green’s functions are characterized by an infinite tail. This implies that the cost complexity of the spatio-temporal convolutions, associated with evaluating the potentials, scales as O(Ns2Nt2), where Ns and Nt are the number of spatial and temporal degrees of freedom, respectively. In this paper, we discuss two new methods to rapidly evaluate these spatio-temporal convolutions by exploiting their block-Toeplitz nature within the framework of accelerated Cartesian expansions (ACE). The first scheme identifies a convolution relation inmore » time amongst ACE harmonics and the fast Fourier transform (FFT) is used for efficient evaluation of these convolutions. The second method exploits the rank deficiency of the ACE translation operators with respect to time and develops a recursive numerical compression scheme for the efficient representation and evaluation of temporal convolutions. It is shown that the cost of both methods scales as O(NsNtlog2Nt). Furthermore, several numerical results are presented for the diffusion equation to validate the accuracy and efficacy of the fast algorithms developed here.« less
Baczewski, Andrew David; Vikram, Melapudi; Shanker, Balasubramaniam; Kempel, Leo
2010-08-27
Diffusion, lossy wave, and Klein–Gordon equations find numerous applications in practical problems across a range of diverse disciplines. The temporal dependence of all three Green’s functions are characterized by an infinite tail. This implies that the cost complexity of the spatio-temporal convolutions, associated with evaluating the potentials, scales as O(N_{s}^{2}N_{t}^{2}), where N_{s} and N_{t} are the number of spatial and temporal degrees of freedom, respectively. In this paper, we discuss two new methods to rapidly evaluate these spatio-temporal convolutions by exploiting their block-Toeplitz nature within the framework of accelerated Cartesian expansions (ACE). The first scheme identifies a convolution relation in time amongst ACE harmonics and the fast Fourier transform (FFT) is used for efficient evaluation of these convolutions. The second method exploits the rank deficiency of the ACE translation operators with respect to time and develops a recursive numerical compression scheme for the efficient representation and evaluation of temporal convolutions. It is shown that the cost of both methods scales as O(N_{s}N_{t}log^{2}N_{t}). Furthermore, several numerical results are presented for the diffusion equation to validate the accuracy and efficacy of the fast algorithms developed here.
Richings, Gareth W; Habershon, Scott
2017-09-12
We describe a method for performing nuclear quantum dynamics calculations using standard, grid-based algorithms, including the multiconfiguration time-dependent Hartree (MCTDH) method, where the potential energy surface (PES) is calculated "on-the-fly". The method of Gaussian process regression (GPR) is used to construct a global representation of the PES using values of the energy at points distributed in molecular configuration space during the course of the wavepacket propagation. We demonstrate this direct dynamics approach for both an analytical PES function describing 3-dimensional proton transfer dynamics in malonaldehyde and for 2- and 6-dimensional quantum dynamics simulations of proton transfer in salicylaldimine. In the case of salicylaldimine we also perform calculations in which the PES is constructed using Hartree-Fock calculations through an interface to an ab initio electronic structure code. In all cases, the results of the quantum dynamics simulations are in excellent agreement with previous simulations of both systems yet do not require prior fitting of a PES at any stage. Our approach (implemented in a development version of the Quantics package) opens a route to performing accurate quantum dynamics simulations via wave function propagation of many-dimensional molecular systems in a direct and efficient manner.
Castro, L. B.; Castro, A. S. de
2010-03-15
It is shown that the paper 'Wave functions for a Duffin-Kemmer-Petiau particle in a time-dependent potential' by Merad and Bensaid [J. Math. Phys. 48, 073515 (2007)] is not correct in using inadvertently a non-Hermitian Hamiltonian in a formalism that does require Hermitian Hamiltonians.
NASA Astrophysics Data System (ADS)
Matsumoto, Hiroaki; Koura, Katsuhisa
1991-12-01
The velocity distribution functions (VDF's) in an argon normal shock wave at an upstream high Mach number 7.183 and low temperature 16 K are calculated using the null-collision direct-simulation Monte Carlo method for the Lennard-Jones (LJ) potential to compare with the experimental results of Holtz and Muntz (1983). The convolved VDF's for the LJ potential are in reasonable agreement with the measured data in early and late regions of the shock wave but significantly different in the middle region. This discrepancy cannot be explained by a possible uncertainty in the potential well depth. Moreover, the difference in the convolved VDF's between the LJ potential and the softest and hardest unrealistic molecular models with no attractive force, i.e., the Maxwell molecule and hard sphere, is much smaller than the discrepancy between the experiments and Monte Carlo calculations.
NASA Astrophysics Data System (ADS)
Matsumoto, Hiroaki; Koura, Katsuhisa
1991-12-01
The velocity distribution functions (VDF's) in an argon normal shock wave at an upstream high Mach number 7.183 and low temperature 16 K are calculated using the null-collision direct-simulation Monte Carlo method for the Lennard-Jones (LJ) potential to compare with the experimental results of Holtz and Muntz [Phys. Fluids 26, 2425 (1983)]. The convolved VDF's for the LJ potential are in reasonable agreement with the measured data in early and late regions of the shock wave but significantly different in the middle region. This discrepancy cannot be explained by a possible uncertainty in the potential well depth. Moreover, the difference in the convolved VDF's between the LJ potential and the softest and hardest unrealistic molecular models with no attractive force, i.e., the Maxwell molecule and hard sphere, is much smaller than the discrepancy between the experiments and Monte Carlo calculations.
NASA Astrophysics Data System (ADS)
Lee, Kyoung-Rok; Koo, Weoncheol; Kim, Moo-Hyun
2013-12-01
A floating Oscillating Water Column (OWC) wave energy converter, a Backward Bent Duct Buoy (BBDB), was simulated using a state-of-the-art, two-dimensional, fully-nonlinear Numerical Wave Tank (NWT) technique. The hydrodynamic performance of the floating OWC device was evaluated in the time domain. The acceleration potential method, with a full-updated kernel matrix calculation associated with a mode decomposition scheme, was implemented to obtain accurate estimates of the hydrodynamic force and displacement of a freely floating BBDB. The developed NWT was based on the potential theory and the boundary element method with constant panels on the boundaries. The mixed Eulerian-Lagrangian (MEL) approach was employed to capture the nonlinear free surfaces inside the chamber that interacted with a pneumatic pressure, induced by the time-varying airflow velocity at the air duct. A special viscous damping was applied to the chamber free surface to represent the viscous energy loss due to the BBDB's shape and motions. The viscous damping coefficient was properly selected using a comparison of the experimental data. The calculated surface elevation, inside and outside the chamber, with a tuned viscous damping correlated reasonably well with the experimental data for various incident wave conditions. The conservation of the total wave energy in the computational domain was confirmed over the entire range of wave frequencies.
Dunkerton, T.J. )
1991-02-20
Eastward and westward traveling waves were observed by the Nimbus 7 Limb Infrared Monitor of the Stratosphere (LIMS) during the northern winter 1978-1979. Eastward waves were prevalent in early winter and were involved in a minor Canadian warming in December 1978. A large westward traveling wave, as described by previous authors, was observed in January 1979 during a series of minor warmings. By comparing these two events, it is shown that in both cases the superposition of traveling and quasi-stationary waves led to constructive interference that was responsible for the warmings. However, there was significant asymmetry between eastward and westward traveling components. Eastward disturbances were confined mostly within the polar vortex, whereas quasi-stationary and westward traveling components propagated to the vortex periphery and beyond, into the tropics and mid-latitude mesosphere. This behavior is consistent with Rossby wave propagation and indicates that the location and magnitude of planetary wave breaking is sensitive to the frequency spectrum entering the middle atmosphere. However, this asymmetry is also a signature of the nonlinear critical layer as it projects onto the frequency spectrum. Both interpretations are shown to be valid during wave events observed by LIMS. A local Eulerian analysis of potential vorticity (PV) transport indicates that adiabatic, geostrophic advection by the resolvable scales of motion explains qualitatively (but not quantitatively) the observed potential vorticity tendencies in the LIMS northern hemisphere winter. In particular, calculated advection explains the eastward rotation of the main vortex, intrusion of low PV air into the polar cap, and formation of high PV filaments at the vortex periphery.
NASA Astrophysics Data System (ADS)
Gauthier, Philippe-Aubert; Berry, Alain; Woszczyk, Wieslaw
2005-09-01
Sound field reproduction finds applications in listening to prerecorded music or in synthesizing virtual acoustics. The objective is to recreate a sound field in a listening environment. Wave field synthesis (WFS) is a known open-loop technology which assumes that the reproduction environment is anechoic. Classical WFS, therefore, does not perform well in a real reproduction space such as room. Previous work has suggested that it is physically possible to reproduce a progressive wave field in-room situation using active control approaches. In this paper, a formulation of adaptive wave field synthesis (AWFS) introduces practical possibilities for an adaptive sound field reproduction combining WFS and active control (with WFS departure penalization) with a limited number of error sensors. AWFS includes WFS and closed-loop ``Ambisonics'' as limiting cases. This leads to the modification of the multichannel filtered-reference least-mean-square (FXLMS) and the filtered-error LMS (FELMS) adaptive algorithms for AWFS. Decentralization of AWFS for sound field reproduction is introduced on the basis of sources' and sensors' radiation modes. Such decoupling may lead to decentralized control of source strength distributions and may reduce computational burden of the FXLMS and the FELMS algorithms used for AWFS. [Work funded by NSERC, NATEQ, Université de Sherbrooke and VRQ.] Ultrasound/Bioresponse to
Systems of Nonlinear Hyperbolic Partial Differential Equations
1997-12-01
McKinney) Travelling wave solutions of the modified Korteweg - deVries -Burgers Equation . J. Differential Equations , 116 (1995), 448-467. 4. (with D.G...SUBTITLE Systems of Nonlinear Hyperbolic Partial Differential Equations 6. AUTHOR’S) Michael Shearer PERFORMING ORGANIZATION NAMES(S) AND...DISTRIBUTION CODE 13. ABSTRACT (Maximum 200 words) This project concerns properties of wave propagation in partial differential equations that are nonlinear
Izzati, Wan Akmal; Arief, Yanuar Z; Adzis, Zuraimy; Shafanizam, Mohd
2014-01-01
Polymer nanocomposites have recently been attracting attention among researchers in electrical insulating applications from energy storage to power delivery. However, partial discharge has always been a predecessor to major faults and problems in this field. In addition, there is a lot more to explore, as neither the partial discharge characteristic in nanocomposites nor their electrical properties are clearly understood. By adding a small amount of weight percentage (wt%) of nanofillers, the physical, mechanical, and electrical properties of polymers can be greatly enhanced. For instance, nanofillers in nanocomposites such as silica (SiO2), alumina (Al2O3) and titania (TiO2) play a big role in providing a good approach to increasing the dielectric breakdown strength and partial discharge resistance of nanocomposites. Such polymer nanocomposites will be reviewed thoroughly in this paper, with the different experimental and analytical techniques used in previous studies. This paper also provides an academic review about partial discharge in polymer nanocomposites used as electrical insulating material from previous research, covering aspects of preparation, characteristics of the nanocomposite based on experimental works, application in power systems, methods and techniques of experiment and analysis, and future trends.
Izzati, Wan Akmal; Adzis, Zuraimy; Shafanizam, Mohd
2014-01-01
Polymer nanocomposites have recently been attracting attention among researchers in electrical insulating applications from energy storage to power delivery. However, partial discharge has always been a predecessor to major faults and problems in this field. In addition, there is a lot more to explore, as neither the partial discharge characteristic in nanocomposites nor their electrical properties are clearly understood. By adding a small amount of weight percentage (wt%) of nanofillers, the physical, mechanical, and electrical properties of polymers can be greatly enhanced. For instance, nanofillers in nanocomposites such as silica (SiO2), alumina (Al2O3) and titania (TiO2) play a big role in providing a good approach to increasing the dielectric breakdown strength and partial discharge resistance of nanocomposites. Such polymer nanocomposites will be reviewed thoroughly in this paper, with the different experimental and analytical techniques used in previous studies. This paper also provides an academic review about partial discharge in polymer nanocomposites used as electrical insulating material from previous research, covering aspects of preparation, characteristics of the nanocomposite based on experimental works, application in power systems, methods and techniques of experiment and analysis, and future trends. PMID:24558326
NASA Astrophysics Data System (ADS)
Arefi, Mohammad; Zenkour, Ashraf M.
2016-11-01
Strain gradient theory is used to study free vibration, wave propagation and tension analyses of a sandwich micro/nano rod made of piezoelectric materials under electric potential. The structure is resting on a Pasternak’s foundation medium. Love’s rod model is used for derivation of displacement field. The piezoelectric face sheets are subjected to two-dimensional electric potential including an applied voltage at top of plate and a cosine term along the thickness direction. Hamilton’s principle is used to derive governing equations of motion in terms of axial displacement and electric potential. Three distinct behaviors of the present problem including free vibration, wave propagation and tension analyses are performed. Some important numerical results are presented in detail to capture the effect of materials length scales and applied voltage on the different behaviors of microrod.
Xu, Fuxing; Wang, Liang; Dai, Xinhua; Fang, Xiang; Ding, Chuan-Fan
2014-04-01
Collision-induced dissociation (CID) of ions by resonance activation in a quadrupole ion trap is usually accomplished by resonance exciting the ions to higher kinetic energy, whereby the high kinetic energy ions collide with a bath gas, such as helium or argon, inside the trap and dissociate to fragments. A new ion activation method using a well-defined rectangular wave dipolar potential formed by dividing down the trapping rectangular waveform is developed and examined herein. The mass-selected parent ions are resonance excited to high kinetic energies by simply changing the frequency of the rectangular wave dipolar potential and dissociation proceeds. A relationship between the ion mass and the activation waveform frequency is also identified and described. This highly efficient (CID) procedure can be realized by simply changing the waveform frequency of the dipolar potential, which could certainly simplify tandem mass spectrometry analysis methods.
Oxygen partial pressure sensor
Dees, Dennis W.
1994-01-01
A method for detecting oxygen partial pressure and an oxygen partial pressure sensor are provided. The method for measuring oxygen partial pressure includes contacting oxygen to a solid oxide electrolyte and measuring the subsequent change in electrical conductivity of the solid oxide electrolyte. A solid oxide electrolyte is utilized that contacts both a porous electrode and a nonporous electrode. The electrical conductivity of the solid oxide electrolyte is affected when oxygen from an exhaust stream permeates through the porous electrode to establish an equilibrium of oxygen anions in the electrolyte, thereby displacing electrons throughout the electrolyte to form an electron gradient. By adapting the two electrodes to sense a voltage potential between them, the change in electrolyte conductivity due to oxygen presence can be measured.
Oxygen partial pressure sensor
Dees, D.W.
1994-09-06
A method for detecting oxygen partial pressure and an oxygen partial pressure sensor are provided. The method for measuring oxygen partial pressure includes contacting oxygen to a solid oxide electrolyte and measuring the subsequent change in electrical conductivity of the solid oxide electrolyte. A solid oxide electrolyte is utilized that contacts both a porous electrode and a nonporous electrode. The electrical conductivity of the solid oxide electrolyte is affected when oxygen from an exhaust stream permeates through the porous electrode to establish an equilibrium of oxygen anions in the electrolyte, thereby displacing electrons throughout the electrolyte to form an electron gradient. By adapting the two electrodes to sense a voltage potential between them, the change in electrolyte conductivity due to oxygen presence can be measured. 1 fig.
Agakishiev, G.; Arnold, O.; Belver, D.; Belyaev, A.; Berger-Chen, J. C.; Blanco, A.; Böhmer, M.; Boyard, J. L.; Cabanelas, P.; Chernenko, S.; Dybczak, A.; Epple, E.; Fabbietti, L.; Fateev, O.; Finocchiaro, P.; Fonte, P.; Friese, J.; Fröhlich, I.; Galatyuk, T.; Garzón, J. A.; Gernhäuser, R.; Göbel, K.; Golubeva, M.; González-Díaz, D.; Guber, F.; Gumberidze, M.; Heinz, T.; Hennino, T.; Holzmann, R.; Ierusalimov, A.; Iori, I.; Ivashkin, A.; Jurkovic, M.; Kämpfer, B.; Karavicheva, T.; Koenig, I.; Koenig, W.; Kolb, B. W.; Kornakov, G.; Kotte, R.; Krása, A.; Krizek, F.; Krücken, R.; Kuc, H.; Kühn, W.; Kugler, A.; Kunz, T.; Kurepin, A.; Ladygin, V.; Lalik, R.; Lapidus, K.; Lebedev, A.; Lopes, L.; Lorenz, M.; Maier, L.; Mangiarotti, A.; Markert, J.; Metag, V.; Michel, J.; Müntz, C.; Münzer, R.; Naumann, L.; Pachmayer, Y. C.; Palka, M.; Parpottas, Y.; Pechenov, V.; Pechenova, O.; Pietraszko, J.; Przygoda, W.; Ramstein, B.; Reshetin, A.; Rustamov, A.; Sadovsky, A.; Salabura, P.; Schmah, A.; Schwab, E.; Siebenson, J.; Sobolev, Yu. G.; Spataro, S.; Spruck, B.; Ströbele, H.; Stroth, J.; Sturm, C.; Tarantola, A.; Teilab, K.; Tlusty, P.; Traxler, M.; Tsertos, H.; Vasiliev, T.; Wagner, V.; Weber, M.; Wendisch, C.; Wüstenfeld, J.; Yurevich, S.; Zanevsky, Y.; Sarantsev, A. V.
2015-01-26
Employing the Bonn–Gatchina partial wave analysis framework (PWA), we have analyzed HADES data of the reaction p(3.5GeV) + p → pK^{+}Λ. This reaction might contain information about the kaonic cluster “ppK^{-}” (with quantum numbers J^{P}=0^{-} and total isospin I =1/2) via its decay into pΛ. Due to interference effects in our coherent description of the data, a hypothetical K ¯NN (or, specifically “ppK^{-}”) cluster signal need not necessarily show up as a pronounced feature (e.g. a peak) in an invariant mass spectrum like pΛ. Our PWA analysis includes a variety of resonant and non-resonant intermediate states and delivers a good description of our data (various angular distributions and two-hadron invariant mass spectra) without a contribution of a K ¯NN cluster. At a confidence level of CL_{s}=95% such a cluster cannot contribute more than 2–12% to the total cross section with a pK^{+} Λ final state, which translates into a production cross-section between 0.7 μb and 4.2 μb, respectively. The range of the upper limit depends on the assumed cluster mass, width and production process.
Partial wave analysis of the reaction $\gamma p\to p\omega $ and the search for nucleon resonances
Williams, M.; Applegate, D.; Bellis, M.; Meyer, C. A.; Adhikari, K. P.; Anghinolfi, M.; Baghdasaryan, H.; Ball, J.; Battaglieri, M.; Bedlinskiy, I.; Berman, B. L.; Biselli, A. S.; Briscoe, W. J.; Brooks, W. K.; Burkert, V. D.; Careccia, S. L.; Carman, D. S.; Cole, P. L.; Collins, P.; Crede, V.; D’Angelo, A.; Daniel, A.; De Vita, R.; De Sanctis, E.; Deur, A.; Dey, B.; Dhamija, S.; Dickson, R.; Djalali, C.; Dodge, G. E.; Doughty, D.; Dugger, M.; Dupre, R.; Alaoui, A. El; Elouadrhiri, L.; Eugenio, P.; Fedotov, G.; Fegan, S.; Fradi, A.; Gabrielyan, M. Y.; Garçon, M.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Gohn, W.; Golovatch, E.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guler, N.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Hassall, N.; Hicks, K.; Holtrop, M.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jawalkar, S. S.; Jo, H. S.; Johnstone, J. R.; Joo, K.; Keller, D.; Khandaker, M.; Khetarpal, P.; Kim, W.; Klein, A.; Klein, F. J.; Krahn, Z.; Kubarovsky, V.; Kuleshov, S. V.; Kuznetsov, V.; Livingston, K.; Lu, H. Y.; Mayer, M.; McAndrew, J.; McCracken, M. E.; McKinnon, B.; Mirazita, M.; Mokeev, V.; Moreno, B.; Moriya, K.; Morrison, B.; Munevar, E.; Nadel-Turonski, P.; Nepali, C. S.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Niroula, M. R.; Niyazov, R. A.; Osipenko, M.; Ostrovidov, A. I.; Paris, M.; Park, K.; Park, S.; Pasyuk, E.; Pereira, S. Anefalos; Perrin, Y.; Pisano, S.; Pogorelko, O.; Pozdniakov, S.; Price, J. W.; Procureur, S.; Protopopescu, D.; Ricco, G.; Ripani, M.; Ritchie, B. G.; Rosner, G.; Rossi, P.; Sabatié, F.; Saini, M. S.; Salamanca, J.; Salgado, C.; Schott, D.; Schumacher, R. A.; Seraydaryan, H.; Sharabian, Y. G.; Smith, E. S.; Sober, D. I.; Sokhan, D.; Stepanyan, S. S.; Stoler, P.; Strakovsky, I. I.; Strauch, S.; Taiuti, M.; Tedeschi, D. J.; Tkachenko, S.; Ungaro, M.; Vineyard, M. F.; Voutier, E.; Watts, D. P.; Weygand, D. P.; Wood, M. H.; Zhang, J.; Zhao, B.
2009-12-30
We performed an event-based partial wave analysis (PWA) of the reaction γ p -> p ω on a high-statistics dataset obtained using the CLAS at Jefferson Lab for center-of-mass energies from threshold up to 2.4 GeV. This analysis benefits from access to the world's first high precision spin density matrix element measurements, available to the event-based PWA through the decay distribution of omega-> π^{+} π^{ -} π^{0}. The data confirm the dominance of the t-channel π^{0} exchange amplitude in the forward direction. The dominant resonance contributions are consistent with the previously identified states F[15](1680) and D[13](1700) near threshold, as well as the G[17](2190) at higher energies. Suggestive evidence for the presence of a J(P)=5/2^{+} state around 2 GeV, a "missing" state, has also been found. Evidence for other states is inconclusive.
Hill, David P.
2012-01-01
Hill (2008) and Hill (2010) contain two technical errors: (1) a missing factor of 2 for computed Love‐wave amplitudes, and (2) a sign error in the off‐diagonal elements in the Euler rotation matrix.
Examination of millimeter-wave performance potential of modulation doped AlGaAs/GaAs FET structures
NASA Astrophysics Data System (ADS)
Das, M. B.
1985-09-01
This investigation involved a critical examination of the millimeter-wave performance requirements of the modulation-doped n-AlGaAs/GaAs FET structures. The results of this study revealed the need for a high aspect ration design for the gate structure of MODFET's for millimeter-wave performance. A detailed design procedure has also been developed for submicron gate-length MODFET's, determination of carrier saturation velocity, and power gain and noise figure performance of MODFET's.
2016-06-14
is being developed that makes use of the millimeter wave (MMW) range (30-300 GHz) of the radio frequency region of the electromagnetic spectrum . As...frequency (RF) region of the electromagnetic spectrum is generally defined as including electromag- netic waves with frequencies in the range of 3 kHz...within the RF region of the spectrum , comprising the frequency range from 30 to 300 GHz. Recently, hardware systems capable of g~nerating MMWs have been
Duarte, André G; Katata, Genki; Hoshika, Yasutomo; Hossain, Mohitul; Kreuzwieser, Jürgen; Arneth, Almut; Ruehr, Nadine K
2016-10-20
The frequency and intensity of climatic extremes, such as heat waves, are predicted to increase globally, with severe implications for terrestrial carbon and water cycling. Temperatures may rise above critical thresholds that allow trees to function optimally, with unknown long-term consequences for forest ecosystems. In this context, we investigated how photosynthetic traits and the water balance in Douglas-fir are affected by exposure to three heat waves with temperatures about 12°C above ambient. Photosynthetic carboxylation efficiency (Vcmax) was mostly unaffected, but electron transport (Jmax) and photosynthetic rates under saturating light (Asat) were strongly influenced by the heat waves, with lagging limitations on photosynthesis still being observed six weeks after the last heat wave. We also observed lingering heat-induced inhibitions on transpiration, minimum stomatal conductance, and night-time stomatal conductance (gs-night). Results from the stomatal models used to calculate minimum stomatal conductance were similar to gs-night and indicated changes in leaf morphology, e.g. stomatal occlusions and alterations in epicuticular wax. Our results show Douglas-fir's ability to restrict water loss following heat stress, but at the price of reduced photosynthetic performance. Such limitations indicate potential long-term restrictions that heat waves can impose on tree development and functioning under extreme climatic conditions. Copyright © 2016 Elsevier GmbH. All rights reserved.
The Formation Mechanism of Defects, Spiral Wave in the Network of Neurons
Wu, Xinyi; Ma, Jun
2013-01-01
A regular network of neurons is constructed by using the Morris-Lecar (ML) neuron with the ion channels being considered, and the potential mechnism of the formation of a spiral wave is investigated in detail. Several spiral waves are initiated by blocking the target wave with artificial defects and/or partial blocking (poisoning) in ion channels. Furthermore, possible conditions for spiral wave formation and the effect of partial channel blocking are discussed completely. Our results are summarized as follows. 1) The emergence of a target wave depends on the transmembrane currents with diversity, which mapped from the external forcing current and this kind of diversity is associated with spatial heterogeneity in the media. 2) Distinct spiral wave could be induced to occupy the network when the target wave is broken by partially blocking the ion channels of a fraction of neurons (local poisoned area), and these generated spiral waves are similar with the spiral waves induced by artificial defects. It is confirmed that partial channel blocking of some neurons in the network could play a similar role in breaking a target wave as do artificial defects; 3) Channel noise and additive Gaussian white noise are also considered, and it is confirmed that spiral waves are also induced in the network in the presence of noise. According to the results mentioned above, we conclude that appropriate poisoning in ion channels of neurons in the network acts as ‘defects’ on the evolution of the spatiotemporal pattern, and accounts for the emergence of a spiral wave in the network of neurons. These results could be helpful to understand the potential cause of the formation and development of spiral waves in the cortex of a neuronal system. PMID:23383179
The formation mechanism of defects, spiral wave in the network of neurons.
Wu, Xinyi; Ma, Jun
2013-01-01
A regular network of neurons is constructed by using the Morris-Lecar (ML) neuron with the ion channels being considered, and the potential mechnism of the formation of a spiral wave is investigated in detail. Several spiral waves are initiated by blocking the target wave with artificial defects and/or partial blocking (poisoning) in ion channels. Furthermore, possible conditions for spiral wave formation and the effect of partial channel blocking are discussed completely. Our results are summarized as follows. 1) The emergence of a target wave depends on the transmembrane currents with diversity, which mapped from the external forcing current and this kind of diversity is associated with spatial heterogeneity in the media. 2) Distinct spiral wave could be induced to occupy the network when the target wave is broken by partially blocking the ion channels of a fraction of neurons (local poisoned area), and these generated spiral waves are similar with the spiral waves induced by artificial defects. It is confirmed that partial channel blocking of some neurons in the network could play a similar role in breaking a target wave as do artificial defects; 3) Channel noise and additive Gaussian white noise are also considered, and it is confirmed that spiral waves are also induced in the network in the presence of noise. According to the results mentioned above, we conclude that appropriate poisoning in ion channels of neurons in the network acts as 'defects' on the evolution of the spatiotemporal pattern, and accounts for the emergence of a spiral wave in the network of neurons. These results could be helpful to understand the potential cause of the formation and development of spiral waves in the cortex of a neuronal system.
NASA Astrophysics Data System (ADS)
Kim, E.-H.; Boardsen, S. A.; Johnson, J. R.; Slavin, J. A.
2016-02-01
This chapter provides a brief overview of the observed characteristics of ultra-low-frequency (ULF) waves at Mercury. It shows how field-aligned propagating ULF waves at Mercury can be generated by externally driven fast compressional waves (FWs) via mode conversion at the ion-ion hybrid resonance. Then, the chapter reviews the interpretation that the strong magnetic compressional waves near and its harmonics observed with 20 of Mercury's magnetic equator could be the ion Bernstein wave (IBW) mode. A recent statistical study of ULF waves at Mercury based on MESSENGER data reported the occurrence and polarization of the detected waves. The chapter further introduces the field line resonance and the electromagnetic ion Bernstein waves to explain such waves, and shows that both theories can partially explain the observations.
NASA Astrophysics Data System (ADS)
Dunkerton, Timothy J.
1991-02-01
Eastward and westward traveling waves were observed by the Nimbus 7 Limb Infrared Monitor of the Stratosphere (LIMS) during the northern winter 1978-1979. Eastward waves were prevalent in early winter and were involved in a minor Canadian warming in December 1978. A large westward traveling wave, as described by previous authors, was observed in January 1979 during a series of minor warmings. By comparing these two events, it is shown that in both cases the superposition of traveling and quasi-stationary waves led to constructive interference that was responsible for the warmings. However, there was significant asymmetry between eastward and westward traveling components. A local Eulerian analysis of potential vorticity (PV) transport indicates that adiabatic, geostrophic advection by the resolvable scales of motion explains qualitatively (but not quantitatively) the observed potential vorticity tendencies in the LIMS Northern Hemisphere winter. In particular, calculated advection explains the eastward rotation of the main vortex, intrusion of low PV air into the polar cap, and formation of high PV filaments at the vortex periphery.
Chen, C.; Liu, J.; Xu, S.; Xia, J.; ,
2004-01-01
Geophysical technologies are very effective in environmental, engineering and groundwater applications. Parameters of delineating nature of near-surface materials such as compressional-wave velocity, shear-wave velocity can be obtained using shallow seismic methods. Electric methods are primary approaches for investigating groundwater and detecting leakage. Both of methods are applied to detect embankment in hope of obtaining evidences of the strength and moisture inside the body. A technological experiment has done for detecting and discovering the hidden troubles in the embankment of Yangtze River, Songzi, Hubei, China in 2003. Surface-wave and DC multi-channel array resistivity sounding techniques were used to detect hidden trouble inside and under dike like pipe-seeps. This paper discusses the exploration strategy and the effect of geological characteristics. A practical approach of combining seismic and electric resistivity measurements was applied to locate potential pipe-seeps in embankment in the experiment. The method presents a potential leak factor based on the shear-wave velocity and the resistivity of the medium to evaluate anomalies. An anomaly found in a segment of embankment detected was verified, where occurred a pipe-seep during the 98' flooding.
Vaykshnorayte, Marina A; Azarov, Jan E; Tsvetkova, Alena S; Vityazev, Vladimir A; Ovechkin, Alexey O; Shmakov, Dmitry N
2011-05-01
The study aimed at the simultaneous determination of the transmural and apicobasal differences in the repolarization timing and the comparison of the contributions of these two repolarization gradients to the development of the body surface T wave potentials in animals with the single heart ventricle (fishes and amphibians). Unipolar potentials were measured on the body surface, epicardium and in the intramural (subepicardial, Epi; midmyocardial; and subendocardial, Endo) ventricular layers of 9 pike and 8 frogs. Activation times, repolarization times and activation-recovery intervals were determined. A transmural gradient in repolarization durations in frogs (Endo>Epi, P<0.024) corresponds to the gradient in repolarization times. No significant transmural difference in repolarization duration is observed in pike that produces a repolarization sequence from Endo to Epi (Endo
NASA Astrophysics Data System (ADS)
Keune, Jessica; Sulis, Mauro; Kollet, Stefan; Wada, Yoshihide
2017-04-01
Recent studies indicate that anthropogenic impacts on the terrestrial water cycle lead to a redistribution of water resources in space and time, can trigger land-atmosphere feedbacks, such as the soil moisture-precipitation feedback, and potentially enhance convection and precipitation. Yet, these studies do not consider the full hydrologic cycle from the bedrock to the atmosphere or apply simplified hydrologic models, neglecting the connection of irrigation to water withdrawal and groundwater depletion. Thus, there is a need to incorporate water resource management in 3D hydrologic models coupled to earth system models. This study addresses the impact of water resource management, i.e. irrigation and groundwater abstraction, on land-atmosphere feedbacks through the terrestrial hydrologic cycle in a physics-based soil-vegetation-atmosphere system simulating 3D groundwater dynamics at the continental scale. The integrated Terrestrial Systems Modeling Platform, TerrSysMP, consisting of the three-dimensional subsurface and overland flow model ParFlow, the Community Land Model CLM3.5 and the numerical weather prediction model COSMO of the German Weather Service, is set up over the European CORDEX domain in 0.11° resolution. The model closes the terrestrial water and energy cycles from aquifers into the atmosphere. Anthropogen