Bifurcation structure of localized states in the Lugiato-Lefever equation with anomalous dispersion
Parra-Rivas, P.; Gomila, D.; Gelens, L.; Knobloch, E.
2018-04-01
The origin, stability, and bifurcation structure of different types of bright localized structures described by the Lugiato-Lefever equation are studied. This mean field model describes the nonlinear dynamics of light circulating in fiber cavities and microresonators. In the case of anomalous group velocity dispersion and low values of the intracavity phase detuning these bright states are organized in a homoclinic snaking bifurcation structure. We describe how this bifurcation structure is destroyed when the detuning is increased across a critical value, and determine how a bifurcation structure known as foliated snaking emerges.
Fickian dispersion is anomalous
Cushman, John H.; O'Malley, Dan
2015-12-01
The thesis put forward here is that the occurrence of Fickian dispersion in geophysical settings is a rare event and consequently should be labeled as anomalous. What people classically call anomalous is really the norm. In a Lagrangian setting, a process with mean square displacement which is proportional to time is generally labeled as Fickian dispersion. With a number of counter examples we show why this definition is fraught with difficulty. In a related discussion, we show an infinite second moment does not necessarily imply the process is super dispersive. By employing a rigorous mathematical definition of Fickian dispersion we illustrate why it is so hard to find a Fickian process. We go on to employ a number of renormalization group approaches to classify non-Fickian dispersive behavior. Scaling laws for the probability density function for a dispersive process, the distribution for the first passage times, the mean first passage time, and the finite-size Lyapunov exponent are presented for fixed points of both deterministic and stochastic renormalization group operators. The fixed points of the renormalization group operators are p-self-similar processes. A generalized renormalization group operator is introduced whose fixed points form a set of generalized self-similar processes. Power-law clocks are introduced to examine multi-scaling behavior. Several examples of these ideas are presented and discussed.
Apostolov, S. S.; Makarov, N. M.; Yampol'skii, V. A.
2018-01-01
We study theoretically the optic transmission through a slab of layered superconductor separated from two dielectric leads by spatial gaps. Based on the transfer matrix formalism along with the Josephson plasma electrodynamic approach, we derive analytic expressions for the transmittance and identify the conditions for the perfect transmission. The special interest of the study is focused on the resonant transmission, which occurs when the wave does not propagate in the spatial gaps. Far from the resonance, the transmittance is exponentially small due to the total internal reflection from the lead-gap interface. However, the excitation of electromagnetic modes localized on the layered superconductor gives rise to a remarkable resonant enhancement of the transmission. Moreover, this phenomenon is significantly modified for the layered superconductors in comparison with usual dielectrics or conductors. The dispersion curves for the modes localized on the layered superconductor are proved to be nonmonotonic, thus resulting in the specific dependence of the transmittance T on the incidence angle θ . In particular, we predict the onset of two resonant peaks in the T (θ ) dependence and their subsequent merge into the broadened single peak with increasing of the wave frequency. Our analytical results are demonstrated by numerical data.
Magnetic effects in anomalous dispersion
International Nuclear Information System (INIS)
Blume, M.
1992-01-01
Spectacular enhancements of magnetic x-ray scattering have been predicted and observed experimentally. These effects are the result of resonant phenomena closely related to anomalous dispersion, and they are strongest at near-edge resonances. The theory of these resonances will be developed with particular attention to the symmetry properties of the scatterer. While the phenomena to be discussed concern magnetic properties the transitions are electric dipole or electric quadrupole in character and represent a subset of the usual anomalous dispersion phenomena. The polarization dependence of the scattering is also considered, and the polarization dependence for magnetic effects is related to that for charge scattering and to Templeton type anisotropic polarization phenomena. It has been found that the strongest effects occur in rare-earths and in actinides for M shell edges. In addition to the scattering properties the theory is applicable to ''forward scattering'' properties such as the Faraday effect and circular dichroism
Faraday anomalous dispersion optical tuners
Wanninger, P.; Valdez, E. C.; Shay, T. M.
1992-01-01
Common methods for frequency stabilizing diode lasers systems employ gratings, etalons, optical electric double feedback, atomic resonance, and a Faraday cell with low magnetic field. Our method, the Faraday Anomalous Dispersion Optical Transmitter (FADOT) laser locking, is much simpler than other schemes. The FADOT uses commercial laser diodes with no antireflection coatings, an atomic Faraday cell with a single polarizer, and an output coupler to form a compound cavity. This method is vibration insensitive, thermal expansion effects are minimal, and the system has a frequency pull in range of 443.2 GHz (9A). Our technique is based on the Faraday anomalous dispersion optical filter. This method has potential applications in optical communication, remote sensing, and pumping laser excited optical filters. We present the first theoretical model for the FADOT and compare the calculations to our experimental results.
Faraday anomalous dispersion optical filters
Shay, T. M.; Yin, B.; Alvarez, L. S.
1993-01-01
The effect of Faraday anomalous dispersion optical filters on infrared and blue transitions of some alkali atoms is calculated. A composite system is designed to further increase the background noise rejection. The measured results of the solar background rejection and image quality through the filter are presented. The results show that the filter may provide high transmission and high background noise rejection with excellent image quality.
Anomalous dispersion enhanced Cerenkov phase-matching
Energy Technology Data Exchange (ETDEWEB)
Kowalczyk, T.C.; Singer, K.D. [Case Western Reserve Univ., Cleveland, OH (United States). Dept. of Physics; Cahill, P.A. [Sandia National Labs., Albuquerque, NM (United States)
1993-11-01
The authors report on a scheme for phase-matching second harmonic generation in polymer waveguides based on the use of anomalous dispersion to optimize Cerenkov phase matching. They have used the theoretical results of Hashizume et al. and Onda and Ito to design an optimum structure for phase-matched conversion. They have found that the use of anomalous dispersion in the design results in a 100-fold enhancement in the calculated conversion efficiency. This technique also overcomes the limitation of anomalous dispersion phase-matching which results from absorption at the second harmonic. Experiments are in progress to demonstrate these results.
Diffraction anomalous fine structure using X-ray anomalous dispersion
International Nuclear Information System (INIS)
Soejima, Yuji; Kuwajima, Shuichiro
1998-01-01
A use of X-ray anomalous dispersion effects for structure investigation has recently been developed by using synchrotron radiation. One of the interesting method is the observation of anomalous fine structure which arise on diffraction intensity in energy region of incident X-ray at and higher than absorption edge. The phenomenon is so called Diffraction Anomalous Fine Structure (DAFS). DAFS originates in the same physical process an that of EXAFS: namely photoelectric effect at the corresponding atom and the interaction of photoelectron waves between the atom and neighboring atoms. In contrast with EXAFS, the method is available for only the crystalline materials, but shows effective advantages of the structure investigations by a use of diffraction: one is the site selectivity and the other is space selectivity. In the present study, demonstrations of a use of X-ray anomalous dispersion effect for the superstructure determination will be given for the case of PbZrO 3 , then recent trial investigations of DAFS in particular on the superlattice reflections will be introduced. In addition, we discuss about Forbidden Reflection near Edge Diffraction (FRED) which is more recently investigated as a new method of the structure analysis. (author)
Powder diffraction studies using anomalous dispersion
International Nuclear Information System (INIS)
Cox, D.E.; Wilkinson, A.P.
1993-01-01
With the increasing availability and accessibility of high resolution powder diffractometers at many synchrotron radiation sources throughout the world, there is rapidly-growing interest in the exploitation of anomalous dispersion techniques for structural studies of polycrystalline materials. In conjunction with the Rietveld profile method for structure refinement, such studies are especially useful for the determination of the site distributions of two or more atoms which are near neighbors in the periodic table, or atoms which are distributed among partially occupied sites. Additionally, it is possible to (1) determine the mean-square displacements associated with different kinds of atoms distributed over a single set of sites, (2) distinguish between different oxidation states and coordination geometries of a particular atom in a compound and (3) to determine f' for a wide range of atomic species as a function of energy in the vicinity of an absorption edge. Experimental methods for making anomalous dispersion measurements are described in some detail, including data collection strategies, data analysis and correlation problems, possible systematic errors, and the accuracy of the results. Recent work in the field is reviewed, including cation site-distribution studies (e.g. doped high T c superconductors, ternary alloys, FeCo 2 (PO 4 ) 3 , FeNi 2 BO 5 ), oxidation-state contrast (e.g. YBa 2 Cu 3 O 6+x , Eu 3 O 4 , GaCl 2 , Fe 2 PO 5 ), and the effect of coordination geometry (e.g. Y 3 Ga 5 O l2 )
Anomalous acoustic dispersion in architected microlattice metamaterials
KröDel, Sebastian; Palermo, Antonio; Daraio, Chiara
The ability to control dispersion in acoustic metamaterials is crucial to realize acoustic filtering and rectification devices as well as perfect imaging using negative refractive index materials. Architected microlattice metamaterials immersed in fluid constitute a versatile platform for achieving such control. We investigate architected microlattice materials able to exploit locally resonant modes of their fundamental building blocks that couple with propagating acoustic waves. Using analytical, numerical and experimental methods we find that such lattice materials show a hybrid dispersion behavior governed by Biot's theory for long wavelengths and multiple scattering theory when wave frequency is close to the resonances of the building block. We identify the relevant geometric parameters to alter and control the group and phase velocities in this class of acoustic metamaterials. Furthermore, we fabricate small-scale acoustic metamaterial samples using high precision SLA additive manufacturing and test the resulting materials experimentally using a customized ultrasonic setup. This work paves the way for new acoustic devices based on microlattice metamaterials.
Vacuum field energy and spontaneous emission in anomalously dispersive cavities
International Nuclear Information System (INIS)
Bradshaw, Douglas H.; Di Rosa, Michael D.
2011-01-01
Anomalously dispersive cavities, particularly white-light cavities, may have larger bandwidth to finesse ratios than their normally dispersive counterparts. Partly for this reason, they have been proposed for use in laser interferometer gravitational-wave observatory (LIGO)-like gravity-wave detectors and in ring-laser gyroscopes. In this paper we analyze the quantum noise associated with anomalously dispersive cavity modes. The vacuum field energy associated with a particular cavity mode is proportional to the cavity-averaged group velocity of that mode. For anomalously dispersive cavities with group index values between 1 and 0, this means that the total vacuum field energy associated with a particular cavity mode must exceed (ℎ/2π)ω/2. For white-light cavities in particular, the group index approaches zero and the vacuum field energy of a particular spatial mode may be significantly enhanced. We predict enhanced spontaneous emission rates into anomalously dispersive cavity modes and broadened laser linewidths when the linewidth of intracavity emitters is broader than the cavity linewidth.
Anomalous dispersion due to hydrocarbons: The secret of reservoir geophysics?
Brown, R.L.
2009-01-01
When P- and S-waves travel through porous sandstone saturated with hydrocarbons, a bit of magic happens to make the velocities of these waves more frequency-dependent (dispersive) than when the formation is saturated with brine. This article explores the utility of the anomalous dispersion in finding more oil and gas, as well as giving a possible explanation about the effect of hydrocarbons upon the capillary forces in the formation. ?? 2009 Society of Exploration Geophysicists.
Use of the babinet compensator for anomalous dispersion measurements.
Izatt, J R; Boyle, L J
1973-01-01
Reorientation of the optical elements in a standard experimental setup that utilizes a Babinet compensator to measure the anomalous dispersion of a birefringent mediumn results in a useful trade-off between the intensity and visibility of the polarization fringes produced by the apparatus. The fringe pattern is analyzed and numerical results are presented that illustrate the nature of the trade-off and its application to measurements near the center of a strong absorption line.
Multisplitting and collapse of self-focusing anisotropic beams in normal/anomalous dispersive media
DEFF Research Database (Denmark)
Bergé, L.; Juul Rasmussen, J.
1996-01-01
Three-dimensional self-focusing light pulses in normal and anomalous dispersive media are investigated by means of a waveguide instability analysis, a Lagrangian approach, and a quasi-self-similar analysis. In the case of normal dispersion for which no localized ground state exists, it is shown....... The mechanism underlying this fragmentation process is described in terms of a stretching of the self-focusing beam along its propagation axis. The focal point, where the splitting process develops, is identified. Finally, it is shown that the longitudinal dynamical motions of self-focusing elongated pulses...
Anomalous Hall conductivity: Local orbitals approach
Czech Academy of Sciences Publication Activity Database
Středa, Pavel
2010-01-01
Roč. 82, č. 4 (2010), 045115/1-045115/9 ISSN 1098-0121 Institutional research plan: CEZ:AV0Z10100521 Keywords : anomalous Hall effect * Berry phase correction * orbital polarization momentum Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.772, year: 2010
Symmetrized local co-registration optimization for anomalous change detection
Energy Technology Data Exchange (ETDEWEB)
Wohlberg, Brendt E [Los Alamos National Laboratory; Theiler, James P [Los Alamos National Laboratory
2009-01-01
The goal of anomalous change detection (ACD) is to identify what unusual changes have occurred in a scene, based on two images of the scene taken at different times and under different conditions. The actual anomalous changes need to be distinguished from the incidental differences that occur throughout the imagery, and one of the most common and confounding of these incidental differences is due to the misregistration of the images, due to limitations of the registration pre-processing applied to the image pair. We propose a general method to compensate for residual misregistration in any ACD algorithm which constructs an estimate of the degree of 'anomalousness' for every pixel in the image pair. The method computes a modified misregistration-insensitive anomalousness by making local re-registration adjustments to minimize the local anomalousness. In this paper we describe a symmetrized version of our initial algorithm, and find significant performance improvements in the anomalous change detection ROC curves for a number of real and synthetic data sets.
Electrodeless-discharge-vapor-lamp-based Faraday anomalous-dispersion optical filter.
Sun, Qinqing; Zhuang, Wei; Liu, Zhiwen; Chen, Jingbiao
2011-12-01
We report an excited-state Faraday anomalous-dispersion optical filter operating on the rubidium 5P(3/2)-5D(5/2) transition (775.9 nm in vacuum) without the use of a pump laser. An electrodeless discharge vapor lamp is employed to replace the Rb vapor cell in a traditional Faraday anomalous-dispersion optical filter system. Atoms can be excited by power rather than a complex frequency-locked pump laser. A proof-of-concept experimental demonstration with a maximum transmission of 1.9% and a filter bandwidth of 650 MHz is presented. © 2011 Optical Society of America
Energy Technology Data Exchange (ETDEWEB)
Wang, Guanghui, E-mail: wanggh@scnu.edu.cn; Lei, Yuandong; Zhang, Weifeng
2015-02-20
Dispersion properties of transverse magnetic (TM) waves in a subwavelength metallic waveguide loaded by uniaxial metamaterials are investigated, based on two kinds of uniaxial metamaterials with different orientations of optical axis. The numerical results show that the existence of fundamental TM{sub 0} mode and high-order TM modes in the waveguide system is dependent on the orientation of optical axis. In addition, their anomalous dispersion properties are clarified. When the orientation of optical axis is selected properly, there are two branches of dispersion curves for each high-order mode—one is normal dispersion and another belongs to anomalous dispersion, showing a transition from a backward wave to a forward one with the increase of working frequency. Moreover, the group velocity and energy flow distribution for TM{sub 1} mode are also demonstrated. These properties may have potential applications in optical information storage, integrated optics and nanophotonic devices. - Highlights: • Two kinds of subwavelength uniaxial metamaterial waveguides are constructed. • We demonstrate anomalous dispersion properties of transverse magnetic (TM) guided modes. • There are two branches of dispersion curves for high-order TM modes, showing a transition from a backward wave to a forward one. • Group velocity can approach to zero, having potential application in optical information storage. • Negative group velocity and energy flow distribution for TM modes are shown.
Anomalous dissolution behaviour of tablets prepared from sugar glass-based solid dispersions
Van Drooge, D.J.; Hinrichs, W.L.J.; Frijlink, H.W.
2004-01-01
In this study, anomalous dissolution behaviour of tablets consisting of sugar glass dispersions was investigated. The poorly aqueous soluble diazepam was used as a lipophilic model drug. The release of diazepam and sugar carrier was determined to study the mechanisms governing dissolution behaviour.
Frequency doubling in poled polymers using anomalous dispersion phase-matching
Energy Technology Data Exchange (ETDEWEB)
Kowalczyk, T.C.; Singer, K.D. [Case Western Reserve Univ., Cleveland, OH (United States). Dept. of Physics; Cahill, P.A. [Sandia National Labs., Albuquerque, NM (United States)
1995-10-01
The authors report on a second harmonic generation in a poled polymer waveguide using anomalous dispersion phase-matching. Blue light ({lambda} = 407 nm) was produced by phase-matching the lowest order fundamental and harmonic modes over a distance of 32 {micro}m. The experimental conversion efficiency was {eta} = 1.2 {times} 10{sup {minus}4}, in agreement with theory. Additionally, they discuss a method of enhancing the conversion efficiency for second harmonic generation using anomalous dispersion phase-matching to optimize Cerenkov second harmonic generation. The modeling shows that a combination of phase-matching techniques creates larger conversion efficiencies and reduces critical fabrication requirements of the individual phase-matching techniques.
International Nuclear Information System (INIS)
Liu Xueming
2011-01-01
The soliton formation and evolution are numerically and experimentally investigated in passively-mode-locked lasers where pulses encounter ultralong anomalous-dispersion fibers. The pulse formation and evolution in lasers are determined by two balances, namely, nonlinearity and anomalous-dispersion balance and intracavity filtering and self-amplitude modulation balance. It is numerically found that a higher-energy soliton can be split into identical lower-energy multisolitons with exactly the same physical properties. Simulation results show that the separation of neighboring solitons is variational in the temporal domain. The temporal and spectral characteristics of solitons have large variations throughout the laser cavity, qualitatively distinct from the steady state of conventional solitons. The experimental observations confirm the theoretical predictions.
Anomalous dispersion of magnetic spiky particles for enhanced oil emulsions/water separation.
Chen, Hui-Jiuan; Hang, Tian; Yang, Chengduan; Liu, Guishi; Lin, Di-An; Wu, Jiangming; Pan, Shuolin; Yang, Bo-Ru; Tao, Jun; Xie, Xi
2018-01-25
In situ effective separation of oil pollutants including oil spills and oil emulsions from water is an emerging technology yet remains challenging. Hydrophobic micro- or nano-materials with ferromagnetism have been explored for oil removal, yet the separation efficiency of an oil emulsion was compromised due to the limited dispersion of hydrophobic materials in water. A surfactant coating on microparticles prevented particle aggregation, but reduced oil absorption and emulsion cleaning ability. Recently, polystyrene microbeads covered with nanospikes have been reported to display anomalous dispersion in phobic media without surfactants. Inspired by this phenomenon, here magnetic microparticles attached with nanospikes were fabricated for enhanced separation of oil emulsions from water. In this design, the particle surfaces were functionalized to be superhydrophobic/superoleophilic for oil absorption, while the surface of the nanospikes prevented particle aggregation in water without compromising surface hydrophobicity. The magnetic spiky particles effectively absorbed oil spills on the water surface, and readily dispersed in water and offered facile cleaning of the oil emulsion. In contrast, hydrophobic microparticles without nanospikes aggregated in water limiting the particle-oil contact, while surfactant coating severely reduced particle hydrophobicity and oil absorption ability. Our work provides a unique application scope for the anomalous dispersity of microparticles and their potential opportunities in effective oil-water separation.
Soejima, Y; Sugiyama, M; Annaka, M; Nakamura, A; Hiramatsu, N; Hara, K
2003-01-01
The structure of copper ion clusters in dehydrated N-isopropylacrylamide/sodium acrylate (NIPA/SA) gel has been studied by means of small angle X-ray scattering (SAXS) method. In order to distinguish the intensity scattered by Cu ions, the X-ray anomalous dispersion effect around the Cu K absorption edge has been coupled with SAXS. It is found that the dispersion effect dependent on the incident X-ray energy is remarkable only at the momentum transfer q = 0.031 A sup - sup 1 , where a SAXS peak is observed. The results indicate that copper ions form clusters in the dehydrated gel, and that the mean size of clusters is the same as that of SA clusters produced by microphase separation. It is therefore naturally presumed that copper ions are adsorbed into the SA molecules. On the basis of the presumption, a mechanism is proposed for microphase-separation and clustering of Cu ions.
Zhou, Youbing; Newman, Chris; Chen, Jin; Xie, Zongqiang; Macdonald, David W
2013-09-01
Ongoing global climate change is predicted to increase the frequency and magnitude of extreme weather events, impacting population dynamics and community structure. There is, however, a critical lack of case studies considering how climatic perturbations affect biotic interactions. Here, we document how an obligate seed dispersal mutualism was disrupted by a temporally anomalous and meteorologically extreme interlude of unseasonably frigid weather, with accompanying snowstorms, in subtropical China, during January-February 2008. Based on the analysis of 5892 fecal samples (representing six mammalian seed dispersers), this event caused a substantial disruption to the relative seed dispersal function for the raisin tree Hovenia dulcis from prestorm 6.29 (2006) and 11.47 (2007), down to 0.35 during the storm (2008). Crucially, this was due to impacts on mammalian seed dispersers and not due to a paucity of fruit, where 4.63 fruit per branch were available in January 2008, vs. 3.73 in 2006 and 3.58 in 2007. An induced dietary shift occurred among omnivorous carnivores during this event, from the consumption fruit to small mammals and birds, reducing their role in seed dispersal substantially. Induced range shift extinguished the functionality of herbivorous mammals completely, however, seed dispersal function was compensated in part by three omnivorous carnivores during poststorm years, and thus while the mutualism remained intact it was enacted by a narrower assemblage of species, rendering the system more vulnerable to extrinsic perturbations. The storm's extended effects also had anthropogenic corollaries - migrating ungulates becoming exposed to heightened levels of illegal hunting - causing long-term modification to the seed dispersal community and mutualism dynamics. Furthermore, degraded forests proved especially vulnerable to the storm's effects. Considering increasing climate variability and anthropogenic disturbance, the impacts of such massive, aberrant
Anomalous dispersion in correlated porous media: a coupled continuous time random walk approach
Comolli, Alessandro; Dentz, Marco
2017-09-01
We study the causes of anomalous dispersion in Darcy-scale porous media characterized by spatially heterogeneous hydraulic properties. Spatial variability in hydraulic conductivity leads to spatial variability in the flow properties through Darcy's law and thus impacts on solute and particle transport. We consider purely advective transport in heterogeneity scenarios characterized by broad distributions of heterogeneity length scales and point values. Particle transport is characterized in terms of the stochastic properties of equidistantly sampled Lagrangian velocities, which are determined by the flow and conductivity statistics. The persistence length scales of flow and transport velocities are imprinted in the spatial disorder and reflect the distribution of heterogeneity length scales. Particle transitions over the velocity length scales are kinematically coupled with the transition time through velocity. We show that the average particle motion follows a coupled continuous time random walk (CTRW), which is fully parameterized by the distribution of flow velocities and the medium geometry in terms of the heterogeneity length scales. The coupled CTRW provides a systematic framework for the investigation of the origins of anomalous dispersion in terms of heterogeneity correlation and the distribution of conductivity point values. We derive analytical expressions for the asymptotic scaling of the moments of the spatial particle distribution and first arrival time distribution (FATD), and perform numerical particle tracking simulations of the coupled CTRW to capture the full average transport behavior. Broad distributions of heterogeneity point values and lengths scales may lead to very similar dispersion behaviors in terms of the spatial variance. Their mechanisms, however are very different, which manifests in the distributions of particle positions and arrival times, which plays a central role for the prediction of the fate of dissolved substances in
Pillai, Rajesh S.; Brakenhoff, G. J.; Müller, M.
2006-09-01
The third harmonic generation (THG) axial response in the vicinity of an interface formed by two isotropic materials of normal dispersion is typically single peaked, with the maximum intensity at the interface position. Here it is shown experimentally that this THG z response may show anomalous behavior—being double peaked with a dip coinciding with the interface position—when the THG contributions from both materials are of similar magnitude. The observed anomalous behavior is explained, using paraxial Gaussian theory, by considering dispersion induced shape changes in the THG z response.
Kang, Peter K.; Dentz, Marco; Le Borgne, Tanguy; Lee, Seunghak; Juanes, Ruben
2017-08-01
We investigate tracer transport on random discrete fracture networks that are characterized by the statistics of the fracture geometry and hydraulic conductivity. While it is well known that tracer transport through fractured media can be anomalous and particle injection modes can have major impact on dispersion, the incorporation of injection modes into effective transport modeling has remained an open issue. The fundamental reason behind this challenge is that-even if the Eulerian fluid velocity is steady-the Lagrangian velocity distribution experienced by tracer particles evolves with time from its initial distribution, which is dictated by the injection mode, to a stationary velocity distribution. We quantify this evolution by a Markov model for particle velocities that are equidistantly sampled along trajectories. This stochastic approach allows for the systematic incorporation of the initial velocity distribution and quantifies the interplay between velocity distribution and spatial and temporal correlation. The proposed spatial Markov model is characterized by the initial velocity distribution, which is determined by the particle injection mode, the stationary Lagrangian velocity distribution, which is derived from the Eulerian velocity distribution, and the spatial velocity correlation length, which is related to the characteristic fracture length. This effective model leads to a time-domain random walk for the evolution of particle positions and velocities, whose joint distribution follows a Boltzmann equation. Finally, we demonstrate that the proposed model can successfully predict anomalous transport through discrete fracture networks with different levels of heterogeneity and arbitrary tracer injection modes.
Anomalous hydrodynamical dispersion and the Coats-Smith equation: the finite size effects
International Nuclear Information System (INIS)
Caceres, Manuel O.
2003-09-01
We investigate a family of probability distributions that shows anomalous hydrodynamics dispersion, by solving a particular class of coupled generalized master equations. The Fourier-Laplace solution is obtained analytically in terms of the matrix Green function method; then the Coats-Smith concentration profile is revisited in a particular case. Two models of disorder are worked out explicitly, and the mean current is asymptotically calculated. We present an approximation method to calculate the first passage time distribution for this stochastic transport process, and as an example an exact Markovian result is worked out; scaling results are also shown. We discuss the comparison with other different methods to work out complex diffusion phenomena in the presence of disordered multiple transport paths. Extensions when the models are non diffusive can also be solved in the Fourier-Laplace representation. (author)
Lu, Y. M.
2013-03-05
Scaling of the anomalous Hall conductivity to longitudinal conductivity σAH∝σ2xx has been observed in the dirty regime of two-dimensional weak and strong localization regions in ultrathin, polycrystalline, chemically disordered, ferromagnetic FePt films. The relationship between electron transport and temperature reveals a quantitatively insignificant Coulomb interaction in these films, while the temperature dependent anomalous Hall conductivity experiences quantum correction from electron localization. At the onset of this correction, the low-temperature anomalous Hall resistivity begins to be saturated when the thickness of the FePt film is reduced, and the corresponding Hall conductivity scaling exponent becomes 2, which is above the recent unified theory of 1.6 (σAH∝σ1.6xx). Our results strongly suggest that the correction of the electron localization modulates the scaling exponent of the anomalous Hall effect.
Anomalous resonance-radiation energy-transfer rate in a scattering dispersive medium
International Nuclear Information System (INIS)
Shekhtman, V.L.
1992-01-01
This paper describes a generalization of the concept of group velocity as an energy-transfer rate in a dispersive medium with complex refractive index when the polaritons, which are energy carriers, undergo scattering, in contrast to the classical concept of the group velocity of free polaritons (i.e., without scattering in the medium). The concept of delay time from quantum multichannel-scattering, theory is used as the fundamental concept. Based on Maxwell's equations and the new mathematical Φ-function method, a consistent conceptual definition of group velocity in terms of the ratio of the coherent-energy flux density to the coherent-energy density is obtained for the first time, and a critical analysis of the earlier (Brillouin) understanding of energy-transfer rate is given in the light of radiation-trapping theory and the quantum theory of resonance scattering. The role of generalized group velocity is examined for the interpretation of the phenomenon of multiple resonance scattering, or radiation diffusion. The question of causality for the given problem is touched upon; a new relationship is obtained, called the microcausality condition, which limits the anomalous values of group velocity by way of the indeterminacy principle and the relativistic causality principle for macroscopic time intervals directly measurable in experiment, whereby attention is focused on the connection of the given microcausality condition and the well-known Wigner inequality for the time delay of spherical waves. 22 refs
Using angular dispersion and anomalous transmission to shape ultramonochromatic x rays
Energy Technology Data Exchange (ETDEWEB)
Shvyd' ko, Yuri; Stoupin, Stanislav; Shu, Deming; Khachatryan, Ruben [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States)
2011-11-15
Optical spectrometers, instruments that work with highly monochromatic light, are commonly rated by the spectral bandwidth, which defines the ability to resolve closely spaced spectral components. Another equally important feature is the spectral contrast, the ability to detect faint objects among these components. Here we demonstrate that a combined effect of angular dispersion (AD) and anomalous transmission (AT) of x rays in Bragg reflection from asymmetrically cut crystals can shape spectral distributions of x rays to profiles with high contrast and small bandwidths. The AD and AT x-ray optics is implemented as a five-reflection, three-crystal arrangement featuring a combination of the above-mentioned attributes so desirable for x-ray monochromators and analyzers: a spectral contrast of {approx_equal} 500, a bandwidth of {approx_equal} 0.46 meV, and a remarkably large angular acceptance of {approx_equal} 107 {mu}rad with 9.1 keV x rays. The new optics can become a foundation for the next-generation inelastic x-ray scattering spectrometers for studies of atomic dynamics.
International Nuclear Information System (INIS)
Gražulevičiūtė, I; Garejev, N; Majus, D; Tamošauskas, G; A Dubietis; Jukna, V
2016-01-01
We present a series of measurements, which characterize filamentation dynamics of intense ultrashort laser pulses in the space–time domain, as captured by means of three-dimensional imaging technique in sapphire and fused silica, in the wavelength range of 1.45–2.25 μm, accessing the regimes of weak, moderate and strong anomalous group velocity dispersion (GVD). In the regime of weak anomalous GVD (at 1.45 μm), pulse splitting into two sub-pulses producing a pair of light bullets with spectrally shifted carrier frequencies in both nonlinear media is observed. In contrast, in the regimes of moderate (at 1.8 μm) and strong (at 2.25 μm) anomalous GVD we observe notably different transient dynamics, which however lead to the formation of a single self-compressed quasistationary light bullet with an universal spatiotemporal shape comprised of an extended ring-shaped periphery and a localized intense core that carries the self-compressed pulse. (paper)
Gražulevičiūtė, I.; Garejev, N.; Majus, D.; Jukna, V.; Tamošauskas, G.; Dubietis, A.
2016-02-01
We present a series of measurements, which characterize filamentation dynamics of intense ultrashort laser pulses in the space-time domain, as captured by means of three-dimensional imaging technique in sapphire and fused silica, in the wavelength range of 1.45-2.25 μm, accessing the regimes of weak, moderate and strong anomalous group velocity dispersion (GVD). In the regime of weak anomalous GVD (at 1.45 μm), pulse splitting into two sub-pulses producing a pair of light bullets with spectrally shifted carrier frequencies in both nonlinear media is observed. In contrast, in the regimes of moderate (at 1.8 μm) and strong (at 2.25 μm) anomalous GVD we observe notably different transient dynamics, which however lead to the formation of a single self-compressed quasistationary light bullet with an universal spatiotemporal shape comprised of an extended ring-shaped periphery and a localized intense core that carries the self-compressed pulse.
Constraints for anomalous dimensions of local light-cone operators in [φ3]6 theory
International Nuclear Information System (INIS)
Mueller, D.
1991-01-01
Using the MS scheme, we derive in [φ 3 ] 6 theory the collinear conformal Ward identity for the Green's functions of local light-cone operators of leading twist. The Ward identity for special collinear conformal transformations and renormalization group invariance give constraints for the off-diagonal part of the anomalous dimension matrix for the general case of β≠0. We compute the anomaly of special conformal tranformation in lowest loop order and obtain from the constraints the off-diagonal part of the anomalous dimension in 2-loop order. (orig.)
Anomalously suppressed localization in the two-channel Anderson model
International Nuclear Information System (INIS)
Nguyen, Ba Phi; Kim, Kihong
2012-01-01
We study numerically the localization properties of a two-channel quasi-one-dimensional Anderson model with uncorrelated diagonal disorder within the nearest-neighbor tight-binding approximation. We calculate and analyze the disorder-averaged transmittance and the Lyapunov exponent. We find that the localization of the entire system is enhanced by increasing the interchain hopping strength t-tilde. From the numerical investigation of the energy dependence of the Lyapunov exponent for many different interchain hopping strengths, we find that apart from the band center anomaly, which usually occurs in strictly one-dimensional disordered systems, additional anomalies appear at special spectral points. They are found to be associated with the interchain hopping strength and occur at E=± t-tilde/2 and ± t-tilde. We find that the anomalies at E=± t-tilde are associated with the π-coupling occurring within one energy band and those at E=± t-tilde/2 are associated with the π-coupling occurring between two different energy bands. Despite having a similar origin, these two anomalies have distinct characteristics in their dependence on the strength of disorder. We also show that for a suitable range of parameter values, effectively delocalized states are observed in finite-size systems. (paper)
DEFF Research Database (Denmark)
2015-01-01
(3) with a net positive dispersion. Furthermore, the net positive dispersion in the dispersive unit at least partially compensates for the negative nonlinear phase variation and the negative group-velocity dispersion produced by the bulk quadratic nonlinear medium when the optical pulse passes......A method and a pulse compressor (1) for compressing an optical pulse, wherein the pulse compressor comprising a bulk quadratic nonlinear medium (2) adapted for generating a negative nonlinear phase variation on the optical pulse and having a negative group-velocity dispersion, and a dispersive unit...
Anomalous magnetoresistance effect in sputtered TbFeCo relating to dispersed magnetic moment
International Nuclear Information System (INIS)
Yumoto, S.; Toki, K.; Okada, O.; Gokan, H.
1988-01-01
The electric resistance is sputtered TbFeCo has been measured at room temperature as a function of magnetic field perpendicular to the film plane. Two kinds of anomalous magnetoresistance have been observed. One is a magnetoresistance peak in the magnetization reversal region. The other is reversible change proportional to the applied magnetic field, appearing in the other region. The magnetoresistance peak agrees well with a curve calculated from experimental Hall loop, using a phenomenological relation between anomalous magnetoresistance and anomalous Hall voltage. The magnetoresistance peak is found to originate from magnetic domain walls. The linear magnetoresistance change for TM dominant samples appears in a direction opposite to that for RE dominant samples. The linear change can't be derived from Hall loop
On the propagation of truncated localized waves in dispersive silica
Salem, Mohamed; Bagci, Hakan
2010-01-01
Propagation characteristics of truncated Localized Waves propagating in dispersive silica and free space are numerically analyzed. It is shown that those characteristics are affected by the changes in the relation between the transverse spatial
Anomalous dispersion of optical phonons in La2-xSrxCuO4 at low temperatures
International Nuclear Information System (INIS)
Bishoyi, K.C.; Rout, G.C.; Behera, S.N.
2001-01-01
Inelastic neutron scattering measurements of cuprate system show that a discontinuity in dispersion develops in the middle of the highest energy of optical phonon at low temperatures. We present here a microscopic theory to explain the phonon anomaly in doped cuprate system in normal state. Anti-ferromagnetism due to copper moments is introduced in the electronic Hamiltonian. Phonon coupling to the hybridisation between conduction electrons of the system and the doped f-electrons is incorporated. The phonon self energy due to electron-phonon interaction, which involves the electronic density response function, is evaluated explicitly by Zubarev's Green's function technique in finite temperature and small wave vector limit. The temperature dependence of phonon frequency and the anomalous phonon dispersion are calculated numerically and studied by varying the position of the f-level (ε f ), the effective electron-phonon coupling strength (g), staggered field (h), and the hybridisation parameter (V). (author)
Calculating the anomalous supersymmetry breaking in super Yang-Mills theories with local coupling
International Nuclear Information System (INIS)
Kraus, E.
2002-01-01
Supersymmetric Yang-Mills theories with local gauge coupling have a new type of anomalous breaking, which appears as a breaking of supersymmetry in the Wess-Zumino gauge. The anomalous breaking generates the two-loop order of the gauge β function in terms of the one-loop β function and the anomaly coefficient. We determine the anomaly coefficient in the Wess-Zumino gauge by solving the relevant supersymmetry identities. For this purpose we use a background gauge and show that the anomaly coefficient is uniquely determined by convergent one-loop integrals. When evaluating the one-loop diagrams in the background gauge, it is seen that the anomaly coefficient is determined by the Feynman-gauge value of the one-loop vertex function to G μν G-tilde μν at vanishing momenta
Pamies Porras, Ramón Francisco; Arias Pardilla, Joaquín; Espinosa Rodríguez, Tulia; Carrión Vilches, Francisco José; Bermúdez Olivares, María Dolores; Sanes Molina, José; Avilés González, María Dolores
2018-01-01
New dispersions of few-layers graphene (G) in 1-ethyl-3-methylimidazolium ([EMIM]) ionic liquids (ILs) with dicyanamide ([DCA]) or bis(trifluoromethylsulfonyl)imide ([TFSI]) anions have been obtained by mechanical mixing and sonication. IL+0.5 wt% G dispersions show constant viscosity values from 357K (for IL = [EMIM][DCA]) or from 385K (for IL = [EMIM][TFSI]) to 393K. IL + G dispersions with G > 0.5 wt% show linear viscosity increases with increasing temperature, from 306K (for [EMIM][DCA]+1...
Anderson Localization from the Berry-Curvature Interchange in Quantum Anomalous Hall Systems
Han, Yulei; Qiao, Zhenhua
In this talk, we theoretically investigate the localization mechanism of the quantum anomalous Hall effect (QAHE) in the presence of spin-flip disorders. We show that the QAHE stays quantized at weak disorders, then enters a Berry-curvature mediated metallic phase at moderate disorders, and finally goes into the Anderson insulating phase at strong disorders. From the phase diagram, we find that at the charge neutrality point although the QAHE is most robust against disorders, the corresponding metallic phase is much easier to be localized into the Anderson insulating phase due to the interchange of Berry curvatures carried, respectively, by the conduction and valence bands. In the end, we provide a phenomenological picture related to the topological charges to better understand the underlying physical origin of the QAHE Anderson localization.
Energy Technology Data Exchange (ETDEWEB)
Pawlus, Sebastian; Paluch, Marian; Ziolo, Jerzy [Institute of Physics, University of Silesia, Uniwersytecka 4, Katowice 40-007 (Poland); Kolel-Veetil, Manoj K [Chemistry Division, Code 6127, Naval Research Laboratory, Washington, DC 20375-5342 (United States)
2010-10-20
Broadband dielectric spectroscopic investigations of a vinyl-terminated carboranylenesiloxane, VCS, were performed at ambient and elevated pressures. At a constant structural relaxation time, results show that the structural relaxation dispersion function of VCS narrows with both increasing pressure and temperature. This narrowing is substantial in the case of pressurization and, consequently, the breakdown of the temperature-pressure superposition rule is observed. The interpretation of this breakdown is presented.
Anomalous roughness of turbulent interfaces with system size dependent local roughness exponent
International Nuclear Information System (INIS)
Balankin, Alexander S.; Matamoros, Daniel Morales
2005-01-01
In a system far from equilibrium the system size can play the role of control parameter that governs the spatiotemporal dynamics of the system. Accordingly, the kinetic roughness of interfaces in systems far from equilibrium may depend on the system size. To get an insight into this problem, we performed a detailed study of rough interfaces formed in paper combustion experiments. Using paper sheets of different width λ, we found that the turbulent flame fronts display anomalous multi-scaling characterized by non-universal global roughness exponent α and by the system size dependent spectrum of local roughness exponents, ζ q (λ)=ζ 1 (1)q -ω λ φ q =0.93q -0.15 . The structure factor of turbulent flame fronts also exhibits unconventional scaling dependence on λ. These results are expected to apply to a broad range of far from equilibrium systems when the kinetic energy fluctuations exceed a certain critical value.
International Nuclear Information System (INIS)
Kravtsov, V E; Yudson, V I
2013-01-01
We consider the distribution function P(|ψ| 2 ) of the eigenfunction amplitude at the center-of-band (E = 0) anomaly in the one-dimensional tight-binding chain with weak uncorrelated on-site disorder (the one-dimensional Anderson model). The special emphasis is on the probability of the anomalously localized states (ALS) with |ψ| 2 much larger than the inverse typical localization length ℓ 0 . Using the recently found solution for the generating function Φ an (u, ϕ) we obtain the ALS probability distribution P(|ψ| 2 ) at |ψ| 2 ℓ 0 ≫ 1. As an auxiliary preliminary step, we found the asymptotic form of the generating function Φ an (u, ϕ) at u ≫ 1 which can be used to compute other statistical properties at the center-of-band anomaly. We show that at moderately large values of |ψ| 2 ℓ 0 , the probability of ALS at E = 0 is smaller than at energies away from the anomaly. However, at very large values of |ψ| 2 ℓ 0 , the tendency is inverted: it is exponentially easier to create a very strongly localized state at E = 0 than at energies away from the anomaly. We also found the leading term in the behavior of P(|ψ| 2 ) at small |ψ| 2 ≪ ℓ −1 0 and show that it is consistent with the exponential localization corresponding to the Lyapunov exponent found earlier by Kappus and Wegner. (paper)
Meteorological Controls on Local and Regional Volcanic Ash Dispersal.
Poulidis, Alexandros P; Phillips, Jeremy C; Renfrew, Ian A; Barclay, Jenni; Hogg, Andrew; Jenkins, Susanna F; Robertson, Richard; Pyle, David M
2018-05-02
Volcanic ash has the capacity to impact human health, livestock, crops and infrastructure, including international air traffic. For recent major eruptions, information on the volcanic ash plume has been combined with relatively coarse-resolution meteorological model output to provide simulations of regional ash dispersal, with reasonable success on the scale of hundreds of kilometres. However, to predict and mitigate these impacts locally, significant improvements in modelling capability are required. Here, we present results from a dynamic meteorological-ash-dispersion model configured with sufficient resolution to represent local topographic and convectively-forced flows. We focus on an archetypal volcanic setting, Soufrière, St Vincent, and use the exceptional historical records of the 1902 and 1979 eruptions to challenge our simulations. We find that the evolution and characteristics of ash deposition on St Vincent and nearby islands can be accurately simulated when the wind shear associated with the trade wind inversion and topographically-forced flows are represented. The wind shear plays a primary role and topographic flows a secondary role on ash distribution on local to regional scales. We propose a new explanation for the downwind ash deposition maxima, commonly observed in volcanic eruptions, as resulting from the detailed forcing of mesoscale meteorology on the ash plume.
On the propagation of truncated localized waves in dispersive silica
Salem, Mohamed
2010-01-01
Propagation characteristics of truncated Localized Waves propagating in dispersive silica and free space are numerically analyzed. It is shown that those characteristics are affected by the changes in the relation between the transverse spatial spectral components and the wave vector. Numerical experiments demonstrate that as the non-linearity of this relation gets stronger, the pulses propagating in silica become more immune to decay and distortion whereas the pulses propagating in free-space suffer from early decay and distortion. © 2010 Optical Society of America.
Lu, Y. M.; Cai, J. W.; Guo, Zaibing; Zhang, Xixiang
2013-01-01
Pt films. The relationship between electron transport and temperature reveals a quantitatively insignificant Coulomb interaction in these films, while the temperature dependent anomalous Hall conductivity experiences quantum correction from electron
Rudolf, Andreas; Walther, Thomas
2012-11-01
We report on the realization of an excited-state Faraday anomalous dispersion optical filter (ESFADOF) edge filter based on the 5P(3/2)→8D(5/2) transition in rubidium. A maximum transmission of 81% has been achieved. This high transmission is only possible by utilizing a special configuration of magnetic fields taken from accelerator physics to provide a strong homogeneous magnetic field of approximately 6000 G across the vapor cell. The two resulting steep transmission edges are separated by more than 13 GHz, enabling its application in remote sensing.
Local orbitals approach to the anomalous Hall and Nernst effects in itinerant ferromagnets
Directory of Open Access Journals (Sweden)
Středa Pavel
2014-07-01
Full Text Available Linear response of the orbital momentum to the gradient of the chemical potential is used to obtain anomalous Hall conductivity. Transition from the ideal Bloch system for which the conductivity is determined by the Berry phase curvatures to the case of strong disorder for which the conductivity becomes dependent on the relaxation time is analysed. Presented tight-binding model reproduces experimentally observed qualitative features of the anomalous Hall conductivity and the transverse Peltier coefficient in the so called bad-metal and scattering-independent regimes.
Tolk, A.
1961-01-01
Some difficulties encountered in the application of the alkali halide disk technique in infra-red spectrometry are discussed. Complications due to interaction of the sample with the alkali halide have been studied experimentally. It was found that the anomalous behaviour of benzoic acid, succinic
Clay squirt: Local flow dispersion in shale-bearing sandstones
DEFF Research Database (Denmark)
Sørensen, Morten Kanne; Fabricius, Ida Lykke
2017-01-01
Dispersion of elastic-wave velocity is common in sandstone and larger in shaly sandstone than in clean sandstone. Dispersion in fluid-saturated shaly sandstone often exceeds the level expected from the stress-dependent elastic moduli of dry sandstone. The large dispersion has been coined clay...... squirt and is proposed to originate from a pressure gradient between the clay microporosity and the effective porosity. We have formulated a simple model that quantifies the clay-squirt effect on bulk moduli of sandstone with homogeneously distributed shale laminae or dispersed shale. The model...... predictions were compared with the literature data. For sandstones with dispersed shale, agreement was found, whereas other sandstones have larger fluid-saturated bulk modulus, possibly due to partially load-bearing shales or heterogeneous shale distribution. The data that agree with the clay-squirt model...
Local extinction and the evolution of dispersal rates: Causes and correlations
Poethke, Hans-Joachim; Hovestadt, Thomas; Mitesser, Oliver
2010-01-01
We present the results of individual-based simulation experiments on the evolution of dispersal rates of organisms living in metapopulations. We find conflicting results regarding the relationship between local extinction rate and evolutionarily stable (ES) dispersal rate depending on which principal mechanism causes extinction: if extinction is caused by environmental catastrophes eradicating local populations, we observe a positive correlation between extinction and ES dispersal rate; if ex...
International Nuclear Information System (INIS)
Wu Yuanfang; Liu Lianshou
1990-01-01
From the study of even and odd multiplicity distributions for hadron-hadron collision in different rapidity windows, we propose a simple picture for charge correlation with nonzero correlation length and calculate the multiplicity distributions and the normalized moments in different rapidity windows at different energies. The results explain the experimentally observed coincidence and separation of even and odd distributions and also the anomalous energy dependence of normalized moments in narrow rapidity windows. The reason for the separation of even-odd distributions, appearing first at large multiplicities, is shown to be energy conservation. The special role of no-particle events in narrow rapidity windows is pointed out
Wandrag, Elizabeth M; Dunham, Amy E; Duncan, Richard P; Rogers, Haldre S
2017-10-03
Dispersal is thought to be a key process underlying the high spatial diversity of tropical forests. Just how important dispersal is in structuring plant communities is nevertheless an open question because it is very difficult to isolate dispersal from other processes, and thereby measure its effect. Using a unique situation, the loss of vertebrate seed dispersers on the island of Guam and their presence on the neighboring islands of Saipan and Rota, we quantify the contribution of vertebrate seed dispersal to spatial patterns of diversity of tree seedlings in treefall gaps. The presence of vertebrate seed dispersers approximately doubled seedling species richness within canopy gaps and halved species turnover among gaps. Our study demonstrates that dispersal plays a key role in maintaining local and regional patterns of diversity, and highlights the potential for ongoing declines in vertebrate seed dispersers to profoundly alter tropical forest composition.
Kimura, Yuji; Haraguchi, Kazutoshi
2017-05-16
Clay-alcohol-water ternary dispersions were compared with alcohol-water binary mixtures in terms of viscosity and optical absorbance. Aqueous clay dispersions to which lower alcohols (ethanol, 1-propanol, 2-propanol, and tert-butanol) were added exhibited significant viscosity anomalies (maxima) when the alcohol content was 30-55 wt %, as well as optical absorbance anomalies (maxima). The maximum viscosity (η max ) depended strongly on the clay content and varied between 300 and 8000 mPa·s, making it remarkably high compared with the viscosity anomalies (2 mPa·s) observed in alcohol-water binary mixtures. The alcohol content at η max decreased as the hydrophobicity of the alcohol increased. The ternary dispersions with viscosity anomalies exhibited thixotropic behaviors. The effects of other hydrophilic solvents (glycols) and other kinds of clays were also clarified. Based on these findings and the average particle size changes, the viscosity anomalies in the ternary dispersions were explained by alcohol-clustering-induced network formation of the clay nanosheets. It was estimated that 0.9, 1.7, and 2.5 H 2 O molecules per alcohol molecule were required to stabilize the ethanol, 2-propanol, and tert-butanol, respectively, in the clay-alcohol-water dispersions.
A hybrid plume model for local-scale dispersion
Energy Technology Data Exchange (ETDEWEB)
Nikmo, J.; Tuovinen, J.P.; Kukkonen, J.; Valkama, I.
1997-12-31
The report describes the contribution of the Finnish Meteorological Institute to the project `Dispersion from Strongly Buoyant Sources`, under the `Environment` programme of the European Union. The project addresses the atmospheric dispersion of gases and particles emitted from typical fires in warehouses and chemical stores. In the study only the `passive plume` regime, in which the influence of plume buoyancy is no longer important, is addressed. The mathematical model developed and its numerical testing is discussed. The model is based on atmospheric boundary-layer scaling theory. In the vicinity of the source, Gaussian equations are used in both the horizontal and vertical directions. After a specified transition distance, gradient transfer theory is applied in the vertical direction, while the horizontal dispersion is still assumed to be Gaussian. The dispersion parameters and eddy diffusivity are modelled in a form which facilitates the use of a meteorological pre-processor. Also a new model for the vertical eddy diffusivity (K{sub z}), which is a continuous function of height in the various atmospheric scaling regions is presented. The model includes a treatment of the dry deposition of gases and particulate matter, but wet deposition has been neglected. A numerical solver for the atmospheric diffusion equation (ADE) has been developed. The accuracy of the numerical model was analysed by comparing the model predictions with two analytical solutions of ADE. The numerical deviations of the model predictions from these analytic solutions were less than two per cent for the computational regime. The report gives numerical results for the vertical profiles of the eddy diffusivity and the dispersion parameters, and shows spatial concentration distributions in various atmospheric conditions 39 refs.
Dispersion relation for localized magnetic polaritons propagating at ...
Indian Academy of Sciences (India)
Abstract. Localized magnetic polaritons are investigated in the systems consisting of two magnetic superlattices, coupled by a ferromagnetic contact layer. The general dis- persion relation for localized magnetic polaritons are derived in the framework of the electromagnetic wave theory in the Voigt geometry by the 'transfer' ...
Directory of Open Access Journals (Sweden)
N. Jedrecy
2016-08-01
Full Text Available We show that the well-established universal scaling σxyAHE ∼ σxx1.6 between anomalous Hall and longitudinal conductivities in the low conductivity regime (σxx < 104 Ω−1 cm−1 transforms into the scaling σxyAHE ∼ σxx2 at the onset of strong electron localization. The crossover between the two relations is observed in magnetite-derived ZnxFe3-xO4 thin films where an insulating/hopping regime follows a bad metal/hopping regime below the Verwey transition temperature Tv. Our results demonstrate that electron localization effects come into play in the anomalous Hall effect (AHE modifying significantly the scaling exponent. In addition, the thermal evolution of the anomalous Hall resistivity suggests the existence of spin polarons whose size would decrease below Tv.
International Nuclear Information System (INIS)
Allen, Thomas S.; Prchlik, Jakub J.; Megeath, S. Thomas; Gutermuth, Robert A.; Pipher, Judith L.; Naylor, Tim; Jeffries, R. D.
2014-01-01
We determine the extinction law through Cep OB3b, a young cluster of 3000 stars undergoing gas dispersal. The extinction is measured toward 76 background K giants identified with MMT/Hectospec spectra. Color excess ratios were determined toward each of the giants using V and R photometry from the literature, g, r, i, and z photometry from the Sloan Digital Sky Survey and J, H, and K s photometry from the Two Micron All Sky Survey. These color excess ratios were then used to construct the extinction law through the dusty material associated with Cep OB3b. The extinction law through Cep OB3b is intermediate between the R V = 3.1 and R V = 5 laws commonly used for the diffuse atomic interstellar medium and dense molecular clouds, respectively. The dependence of the extinction law on line-of-sight A V is investigated and we find the extinction law becomes shallower for regions with A V > 2.5 mag. We speculate that the intermediate dust law results from dust processing during the dispersal of the molecular cloud by the cluster.
Energy Technology Data Exchange (ETDEWEB)
Allen, Thomas S.; Prchlik, Jakub J.; Megeath, S. Thomas [University of Toledo, Ritter Astrophysical Observatory, Department of Physics and Astronomy, Toledo, OH 43606 (United States); Gutermuth, Robert A. [Five College Astronomy Department, Smith College, Northampton, MA 01063 (United States); Pipher, Judith L. [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627 (United States); Naylor, Tim [School of Physics, University of Exeter, Exeter, UK EX4 4QL (United Kingdom); Jeffries, R. D. [Astrophysics Group, School of Physical and Geographical Sciences, Keele University, Keele, Staffordshire, UK ST5 5BG (United Kingdom)
2014-05-10
We determine the extinction law through Cep OB3b, a young cluster of 3000 stars undergoing gas dispersal. The extinction is measured toward 76 background K giants identified with MMT/Hectospec spectra. Color excess ratios were determined toward each of the giants using V and R photometry from the literature, g, r, i, and z photometry from the Sloan Digital Sky Survey and J, H, and K{sub s} photometry from the Two Micron All Sky Survey. These color excess ratios were then used to construct the extinction law through the dusty material associated with Cep OB3b. The extinction law through Cep OB3b is intermediate between the R{sub V} = 3.1 and R{sub V} = 5 laws commonly used for the diffuse atomic interstellar medium and dense molecular clouds, respectively. The dependence of the extinction law on line-of-sight A{sub V} is investigated and we find the extinction law becomes shallower for regions with A{sub V} > 2.5 mag. We speculate that the intermediate dust law results from dust processing during the dispersal of the molecular cloud by the cluster.
Ambrosetti, Alberto; Silvestrelli, Pier Luigi
2018-04-01
Dispersion forces play a major role in graphene, largely influencing adhesion of adsorbate moieties and stabilization of functional multilayered structures. However, the reliable prediction of dispersion interactions on graphene up to the relevant ˜10 nm scale is an extremely challenging task: in fact, electromagnetic retardation effects and the highly non-local character of π electrons can imply sizeable qualitative variations of the interaction with respect to known pairwise approaches. Here we address both issues, determining the finite-temperature van der Waals (vdW)-Casimir interaction for point-like and extended adsorbates on graphene, explicitly accounting for the non-local dielectric permittivity. We find that temperature, retardation, and non-locality play a crucial role in determining the actual vdW scaling laws and the stability of both atomic and larger molecular adsorbates. Our results highlight the importance of these effects for a proper description of systems of current high interest, such as graphene interacting with biomolecules, and self-assembly of complex nanoscale structures. Due to the generality of our approach and the observed non-locality of other 2D materials, our results suggest non-trivial vdW interactions from hexagonal mono-layered materials from group 14 of the periodic table, to transition metal dichalcogenides.
Local WKB dispersion relation for the Vlasov-Maxwell equations
International Nuclear Information System (INIS)
Berk, H.L.; Dominguez, R.R.
1982-10-01
A formalism for analyzing systems of integral equations, based on the Wentzel-Kramers-Brillouin (WKB) approximation, is applied to the Vlasov-Maxwell integral equations in an arbitrary-β, spatially inhomogenous plasma model. It is shown that when treating frequencies comparable with and larger than the cyclotron frequency, relevant new terms must be accounted for to treat waves that depend upon local spatial gradients. For a specific model, the response for very short wavelength and high frequency is shown to reduce to the straight-line orbit approximation when the WKB rules are correctly followed
International Nuclear Information System (INIS)
Nozaki, Hiroshi; Fukano, Tatsuo; Ohta, Shingo; Seno, Yoshiki; Katagiri, Hironori; Jimbo, Kazuo
2012-01-01
Highlights: ► Cu 2 ZnSnS 4 thin films as a solar cell material were synthesized. ► The wavelength dependences of the diffraction intensity were measured. ► The crystal structures were clearly identified as kesterite structure for all samples. ► Crystal structure analysis revealed that the atomic compositions were Cu/(Zn + Sn) = 0.97 and Zn/Sn = 1.42 for the sample synthesized using stoichiometric amount of starting materials. - Abstract: The crystal structure of Cu 2 ZnSnS 4 (CZTS) thin films fabricated by vapor-phase sulfurization was determined using X-ray anomalous dispersion. High statistic synchrotron radiation X-ray diffraction data were collected from very small amounts of powder. By analyzing the wavelength dependencies of the diffraction peak intensities, the crystal structure was clearly identified as kesterite. Rietveld analysis revealed that the atomic composition deviated from stoichiometric composition, and the compositions were Cu/(Zn + Sn) = 0.97, and Zn/Sn = 1.42.
Valanko, Sebastian; Norkko, Joanna; Norkko, Alf
2015-04-01
In ecology understanding variation in connectivity is central for how biodiversity is maintained. Field studies on dispersal and temporal dynamics in community regulating processes are, however, rare. We test the short-term temporal stability in community composition in a soft-sediment benthic community by determining among-sampling interval similarity in community composition. We relate stability to in situ measures of connectivity (wind, wave, current energy) and rates of dispersal (quantified in different trap types). Waves were an important predictor of when local community taxa are most likely to disperse in different trap-types, suggesting that wave energy is important for connectivity in a region. Community composition at the site was variable and changed stochastically over time. We found changes in community composition (occurrence, abundance, dominance) to be greater at times when connectivity and rates of dispersal were low. In response to periods of lower connectedness dominant taxa in the local community only exhibited change in their relative abundance. In contrast, locally less abundant taxa varied in both their presence, as well as in relative abundance. Constancy in connectivity and rates of dispersal promotes community stability and persistence, suggesting that local community composition will be impacted by changes in the spatial extent over which immigration and emigration operates in the region. Few empirical studies have actually measured dispersal directly in a multi-species context to demonstrate the role it plays in maintaining local community structure. Even though our study does not evaluate coexistence over demographic time scales, it importantly demonstrates that dispersal is not only important in initial recruitment or following a disturbance, but also key in maintaining local community composition.
Alajlouni, Sa'ed; Albakri, Mohammad; Tarazaga, Pablo
2018-05-01
An algorithm is introduced to solve the general multilateration (source localization) problem in a dispersive waveguide. The algorithm is designed with the intention of localizing impact forces in a dispersive floor, and can potentially be used to localize and track occupants in a building using vibration sensors connected to the lower surface of the walking floor. The lower the wave frequencies generated by the impact force, the more accurate the localization is expected to be. An impact force acting on a floor, generates a seismic wave that gets distorted as it travels away from the source. This distortion is noticeable even over relatively short traveled distances, and is mainly caused by the dispersion phenomenon among other reasons, therefore using conventional localization/multilateration methods will produce localization error values that are highly variable and occasionally large. The proposed localization approach is based on the fact that the wave's energy, calculated over some time window, decays exponentially as the wave travels away from the source. Although localization methods that assume exponential decay exist in the literature (in the field of wireless communications), these methods have only been considered for wave propagation in non-dispersive media, in addition to the limiting assumption required by these methods that the source must not coincide with a sensor location. As a result, these methods cannot be applied to the indoor localization problem in their current form. We show how our proposed method is different from the other methods, and that it overcomes the source-sensor location coincidence limitation. Theoretical analysis and experimental data will be used to motivate and justify the pursuit of the proposed approach for localization in a dispersive medium. Additionally, hammer impacts on an instrumented floor section inside an operational building, as well as finite element model simulations, are used to evaluate the performance of
Chen, Chung-De; Huang, Yen-Chieh; Chiang, Hsin-Lin; Hsieh, Yin-Cheng; Guan, Hong-Hsiang; Chuankhayan, Phimonphan; Chen, Chun-Jung
2014-09-01
Optimization of the initial phasing has been a decisive factor in the success of the subsequent electron-density modification, model building and structure determination of biological macromolecules using the single-wavelength anomalous dispersion (SAD) method. Two possible phase solutions (φ1 and φ2) generated from two symmetric phase triangles in the Harker construction for the SAD method cause the well known phase ambiguity. A novel direct phase-selection method utilizing the θ(DS) list as a criterion to select optimized phases φ(am) from φ1 or φ2 of a subset of reflections with a high percentage of correct phases to replace the corresponding initial SAD phases φ(SAD) has been developed. Based on this work, reflections with an angle θ(DS) in the range 35-145° are selected for an optimized improvement, where θ(DS) is the angle between the initial phase φ(SAD) and a preliminary density-modification (DM) phase φ(DM)(NHL). The results show that utilizing the additional direct phase-selection step prior to simple solvent flattening without phase combination using existing DM programs, such as RESOLVE or DM from CCP4, significantly improves the final phases in terms of increased correlation coefficients of electron-density maps and diminished mean phase errors. With the improved phases and density maps from the direct phase-selection method, the completeness of residues of protein molecules built with main chains and side chains is enhanced for efficient structure determination.
International Nuclear Information System (INIS)
Chen, Chung-De; Huang, Yen-Chieh; Chiang, Hsin-Lin; Hsieh, Yin-Cheng; Guan, Hong-Hsiang; Chuankhayan, Phimonphan; Chen, Chun-Jung
2014-01-01
A novel direct phase-selection method to select optimized phases from the ambiguous phases of a subset of reflections to replace the corresponding initial SAD phases has been developed. With the improved phases, the completeness of built residues of protein molecules is enhanced for efficient structure determination. Optimization of the initial phasing has been a decisive factor in the success of the subsequent electron-density modification, model building and structure determination of biological macromolecules using the single-wavelength anomalous dispersion (SAD) method. Two possible phase solutions (ϕ 1 and ϕ 2 ) generated from two symmetric phase triangles in the Harker construction for the SAD method cause the well known phase ambiguity. A novel direct phase-selection method utilizing the θ DS list as a criterion to select optimized phases ϕ am from ϕ 1 or ϕ 2 of a subset of reflections with a high percentage of correct phases to replace the corresponding initial SAD phases ϕ SAD has been developed. Based on this work, reflections with an angle θ DS in the range 35–145° are selected for an optimized improvement, where θ DS is the angle between the initial phase ϕ SAD and a preliminary density-modification (DM) phase ϕ DM NHL . The results show that utilizing the additional direct phase-selection step prior to simple solvent flattening without phase combination using existing DM programs, such as RESOLVE or DM from CCP4, significantly improves the final phases in terms of increased correlation coefficients of electron-density maps and diminished mean phase errors. With the improved phases and density maps from the direct phase-selection method, the completeness of residues of protein molecules built with main chains and side chains is enhanced for efficient structure determination
Michler, Stephanie P. M.; Nicolaus, Marion; Ubels, Richard; van der Velde, Marco; Komdeur, Jan; Both, Christiaan; Tinbergen, Joost M.; Gibson, R.
2011-01-01
An individual's decision to disperse from the natal habitat can affect its future fitness prospects. Especially in species with sex-biased dispersal, we expect the cost benefit balance for dispersal to vary according to the social environment (e.g., local sex ratio and density). However, little is
Primary assembly of soil communities: disentangling the effect of dispersal and local environment.
Ingimarsdóttir, María; Caruso, Tancredi; Ripa, Jörgen; Magnúsdóttir, Olöf Birna; Migliorini, Massimo; Hedlund, Katarina
2012-11-01
It has long been recognised that dispersal abilities and environmental factors are important in shaping invertebrate communities, but their relative importance for primary soil community assembly has not yet been disentangled. By studying soil communities along chronosequences on four recently emerged nunataks (ice-free land in glacial areas) in Iceland, we replicated environmental conditions spatially at various geographical distances. This allowed us to determine the underlying factors of primary community assembly with the help of metacommunity theories that predict different levels of dispersal constraints and effects of the local environment. Comparing community assembly of the nunataks with that of non-isolated deglaciated areas indicated that isolation of a few kilometres did not affect the colonisation of the soil invertebrates. When accounting for effects of geographical distances, soil age and plant richness explained a significant part of the variance observed in the distribution of the oribatid mites and collembola communities, respectively. Furthermore, null model analyses revealed less co-occurrence than expected by chance and also convergence in the body size ratio of co-occurring oribatids, which is consistent with species sorting. Geographical distances influenced species composition, indicating that the community is also assembled by dispersal, e.g. mass effect. When all the results are linked together, they demonstrate that local environmental factors are important in structuring the soil community assembly, but are accompanied with effects of dispersal that may "override" the visible effect of the local environment.
Energy Technology Data Exchange (ETDEWEB)
Jedrecy, N., E-mail: jedrecy@insp.jussieu.fr; Hamieh, M.; Hebert, C.; Escudier, M.; Becerra, L.; Perriere, J. [Institut des Nano Sciences de Paris, UPMC-Sorbonne Universités, CNRS-UMR7588, 4 Place Jussieu, 75252 Paris Cedex 05 (France)
2016-08-15
We show that the well-established universal scaling σ{sub xy}{sup AHE} ∼ σ{sub xx}{sup 1.6} between anomalous Hall and longitudinal conductivities in the low conductivity regime (σ{sub xx} < 10{sup 4} Ω{sup −1} cm{sup −1}) transforms into the scaling σ{sub xy}{sup AHE} ∼ σ{sub xx}{sup 2} at the onset of strong electron localization. The crossover between the two relations is observed in magnetite-derived Zn{sub x}Fe{sub 3-x}O{sub 4} thin films where an insulating/hopping regime follows a bad metal/hopping regime below the Verwey transition temperature T{sub v}. Our results demonstrate that electron localization effects come into play in the anomalous Hall effect (AHE) modifying significantly the scaling exponent. In addition, the thermal evolution of the anomalous Hall resistivity suggests the existence of spin polarons whose size would decrease below T{sub v}.
Turunen, Jarno; Louhi, Pauliina; Mykrä, Heikki; Aroviita, Jukka; Putkonen, Emmi; Huusko, Ari; Muotka, Timo
2018-06-06
The effects of anthropogenic stressors on community structure and ecosystem functioning can be strongly influenced by local habitat structure and dispersal from source communities. Catchment land uses increase the input of fine sediments into stream channels, clogging the interstitial spaces of benthic habitats. Aquatic macrophytes enhance habitat heterogeneity and mediate important ecosystem functions, being thus a key component of habitat structure in many streams. Therefore, the recovery of macrophytes following in-stream habitat modification may be prerequisite for successful stream restoration. Restoration success is also affected by dispersal of organisms from the source community, with potentially strongest responses in relatively isolated headwater sites that receive limited amount of dispersing individuals. We used a factorial design in a set of stream mesocosms to study the independent and combined effects of an anthropogenic stressor (sand sedimentation), local habitat (macrophytes, i.e. moss transplants) and enhanced dispersal (two levels: high vs. low) on organic matter retention, algal accrual rate, leaf decomposition and macroinvertebrate community structure. Overall, all responses were simple additive effects with no interactions between treatments. Sand reduced algal accumulation, total invertebrate density and density of a few individual taxa. Mosses reduced algal accrual rate and algae-grazing invertebrates, but enhanced organic matter retention and detritus- and filter-feeders. Mosses also reduced macroinvertebrate diversity by increasing the dominance by a few taxa. Mosses also reduced leaf-mass loss, possibly because the organic matter retained by mosses provided an additional food source for leaf-shredding invertebrates and thus reduced shredder aggregation into leaf packs. The effect of mosses on macroinvertebrate communities and ecosystem functioning was distinct irrespective of the level of dispersal, suggesting strong environmental
International Nuclear Information System (INIS)
Turtos, L.; Sanchez, M.; Roque, A.; Soltura, R.
2003-01-01
Methodology for estimation of secondary meteorological variables to be used in local dispersion of air pollutants. This paper include the main works, carried out into the frame of the project Atmospheric environmental externalities of the electricity generation in Cuba, aiming to develop methodologies and corresponding software, which will allow to improve the quality of the secondary meteorological data used in atmospheric pollutant calculations; specifically the wind profiles coefficient, urban and rural mixed high and temperature gradients
Harmansa, Stefan; Alborelli, Ilaria; Bieli, Dimitri; Caussinus, Emmanuel; Affolter, Markus
2017-04-11
The role of protein localization along the apical-basal axis of polarized cells is difficult to investigate in vivo, partially due to lack of suitable tools. Here, we present the GrabFP system, a collection of four nanobody-based GFP-traps that localize to defined positions along the apical-basal axis. We show that the localization preference of the GrabFP traps can impose a novel localization on GFP-tagged target proteins and results in their controlled mislocalization. These new tools were used to mislocalize transmembrane and cytoplasmic GFP fusion proteins in the Drosophila wing disc epithelium and to investigate the effect of protein mislocalization. Furthermore, we used the GrabFP system as a tool to study the extracellular dispersal of the Decapentaplegic (Dpp) protein and show that the Dpp gradient forming in the lateral plane of the Drosophila wing disc epithelium is essential for patterning of the wing imaginal disc.
Laxhammar , Rikard; Falkman , Göran
2012-01-01
Part 4: First Conformal Prediction and Its Applications Workshop (COPA 2012); International audience; Automated detection of anomalous trajectories is an important problem in the surveillance domain. Various algorithms based on learning of normal trajectory patterns have been proposed for this problem. Yet, these algorithms suffer from one or more of the following limitations: First, they are essentially designed for offline anomaly detection in databases. Second, they are insensitive to loca...
Localized in situ polymerization on graphene surfaces for stabilized graphene dispersions.
Das, Sriya; Wajid, Ahmed S; Shelburne, John L; Liao, Yen-Chih; Green, Micah J
2011-06-01
We demonstrate a novel in situ polymerization technique to develop localized polymer coatings on the surface of dispersed pristine graphene sheets. Graphene sheets show great promise as strong, conductive fillers in polymer nanocomposites; however, difficulties in dispersion quality and interfacial strength between filler and matrix have been a persistent problem for graphene-based nanocomposites, particularly for pristine graphene. With this in mind, a physisorbed polymer layer is used to stabilize graphene sheets in solution. To create this protective layer, we formed an organic microenvironment around dispersed graphene sheets in surfactant solutions, and created a nylon 6, 10 or nylon 6, 6 coating via interfacial polymerization. Technique lies at the intersection of emulsion and admicellar polymerization; a similar technique was originally developed to protect luminescent properties of carbon nanotubes in solution. These coated graphene dispersions are aggregation-resistant and may be reversibly redispersed in water even after freeze-drying. The coated graphene holds promise for a number of applications, including multifunctional graphene-polymer nanocomposites. © 2011 American Chemical Society
Ellis, Vincenzo A; Collins, Michael D; Medeiros, Matthew C I; Sari, Eloisa H R; Coffey, Elyse D; Dickerson, Rebecca C; Lugarini, Camile; Stratford, Jeffrey A; Henry, Donata R; Merrill, Loren; Matthews, Alix E; Hanson, Alison A; Roberts, Jackson R; Joyce, Michael; Kunkel, Melanie R; Ricklefs, Robert E
2015-09-08
The drivers of regional parasite distributions are poorly understood, especially in comparison with those of free-living species. For vector-transmitted parasites, in particular, distributions might be influenced by host-switching and by parasite dispersal with primary hosts and vectors. We surveyed haemosporidian blood parasites (Plasmodium and Haemoproteus) of small land birds in eastern North America to characterize a regional parasite community. Distributions of parasite populations generally reflected distributions of their hosts across the region. However, when the interdependence between hosts and parasites was controlled statistically, local host assemblages were related to regional climatic gradients, but parasite assemblages were not. Moreover, because parasite assemblage similarity does not decrease with distance when controlling for host assemblages and climate, parasites evidently disperse readily within the distributions of their hosts. The degree of specialization on hosts varied in some parasite lineages over short periods and small geographic distances independently of the diversity of available hosts and potentially competing parasite lineages. Nonrandom spatial turnover was apparent in parasite lineages infecting one host species that was well-sampled within a single year across its range, plausibly reflecting localized adaptations of hosts and parasites. Overall, populations of avian hosts generally determine the geographic distributions of haemosporidian parasites. However, parasites are not dispersal-limited within their host distributions, and they may switch hosts readily.
The estimation of local marine dispersion of radionuclides from hydrographic survey data
International Nuclear Information System (INIS)
Maul, P.R.
1985-05-01
One of the most important stages in the assessment of the radiological impact of routine discharges of activity to the sea is the estimation of the local dispersion characteristics. Existing methods for defining the parameters required by the computer program CODAR2 are expanded to take into account the significance of the turbulence generated by the discharge, the effect of a shelving sea bed and the variation with time of the lateral dispersion coefficient. These methods also enable the importance of the timing of discharges and the variation of radionuclide concentrations along the coast to be considered. Calculations of local marine dispersion depend directly upon the information that is available from hydrographic surveys. Detailed consideration is given to the definition of model parameter values from data that are generally available from such surveys. The uncertainties involved in mathematical modelling and parameter specification suggest that the long term average radionuclide concentration in the vicinity of the release can be estimated to within a factor of 2 or 3, with estimates more likely to be greater than, rather than less than the actual value. This uncertainty will contribute to the net uncertainty in any radiological assessment of critical group exposure. (author)
RANS modeling of scalar dispersion from localized sources within a simplified urban-area model
Rossi, Riccardo; Capra, Stefano; Iaccarino, Gianluca
2011-11-01
The dispersion of a passive scalar downstream a localized source within a simplified urban-like geometry is examined by means of RANS scalar flux models. The computations are conducted under conditions of neutral stability and for three different incoming wind directions (0°, 45°, 90°) at a roughness Reynolds number of Ret = 391. A Reynolds stress transport model is used to close the flow governing equations whereas both the standard eddy-diffusivity closure and algebraic flux models are employed to close the transport equation for the passive scalar. The comparison with a DNS database shows improved reliability from algebraic scalar flux models towards predicting both the mean concentration and the plume structure. Since algebraic flux models do not increase substantially the computational effort, the results indicate that the use of tensorial-diffusivity can be promising tool for dispersion simulations for the urban environment.
Energy Technology Data Exchange (ETDEWEB)
An, Hye Yeon; Kang, Yoon Hee; Kim, Yoo Keun [Pusan National University, Busan (Korea, Republic of); Song, Sang Keun [Jeju National University, Jeju (Korea, Republic of)
2016-12-15
This study evaluated the atmospheric dispersion of radioactive material according to local weather conditions and emission conditions. Local weather conditions were defined as 8 patterns that frequently occur around the Kori Nuclear Power Plant and emission conditions were defined as 6 patterns from a combination of emission rates and the total number of particles of the {sup 137}Cs, using the WRF/HYSPLIT modeling system. The highest mean concentration of {sup 137}Cs occurred at 0900 LST under the ME4{sub 1} (main wind direction: SSW, daily average wind speed: 2.8 ms{sup -1}), with a wide region of its high concentration due to the continuous wind changes between 0000 and 0900 LST; under the ME3 (NE, 4.1 ms{sup -1}), the highest mean concentration of {sup 137}Cs occurred at 1500 and 2100 LST with a narrow dispersion along a strong northeasterly wind. In the case of ME4{sub 4} (S, 2.7 ms{sup -1}), the highest mean concentration of {sup 137}Cs occurred at 0300 LST because {sup 137}Cs stayed around the KNPP under low wind speed and low boundary layer height. As for the emission conditions, EM1{sub 3} and EM2{sub 3} that had the maximum total number of particles showed the widest dispersion of {sup 137}Cs, while its highest mean concentration was estimated under the EM1{sub 1} considering the relatively narrow dispersion and high emission rate. This study showed that even though an area may be located within the same radius around the Kori Nuclear Power Plant, the distribution and levels of {sup 137}Cs concentration vary according to the change in time and space of weather conditions (the altitude of the atmospheric boundary layer, the horizontal and vertical distribution of the local winds, and the precipitation levels), the topography of the regions where {sup 137}Cs is dispersed, the emission rate of {sup 137}Cs, and the number of emitted particles.
DEFF Research Database (Denmark)
Verhoef, A. J.; Zhu, L.; Israelsen, Stine Møller
2015-01-01
, was investigated for different settings of the intracavity dispersion. When the cavity is operated with close to zero net dispersion, highly stable 0.5-nJ pulses externally compressed to sub-100-fs are generated. These are to our knowledge the shortest pulses generated from an all-polarization-maintaining Yb-fiber......We present an Yb-fiber oscillator with an all-polarizationmaintaining cavity with a higher-order-mode fiber for dispersion compensation. The polarization maintaining higher order mode fiber introduces not only negative second order dispersion but also negative third order dispersion in the cavity......, in contrast to dispersion compensation schemes used in previous demonstrations of all-polarization maintaining Yb-fiber oscillators. The performance of the saturable absorber mirror modelocked oscillator, that employs a free space scheme for coupling onto the saturable absorber mirror and output coupling...
DEFF Research Database (Denmark)
Verhoef, A.J.; Zhu, L.; Israelsen, Stine Møller
2015-01-01
, was investigated for different settings of the intracavity dispersion. When the cavity is operated with close to zero net dispersion, highly stable 0.5-nJ pulses externally compressed to sub-100-fs are generated. These are to our knowledge the shortest pulses generated from an all-polarization-maintaining Yb-fiber......We present an Yb-fiber oscillator with an all-polarization-maintaining cavity with a higher-order-mode fiber for dispersion compensation. The polarization maintaining higher order mode fiber introduces not only negative second order dispersion but also negative third order dispersion in the cavity......, in contrast to dispersion compensation schemes used in previous demonstrations of all-polarization maintaining Yb-fiber oscillators. The performance of the saturable absorber mirror modelocked oscillator, that employs a free space scheme for coupling onto the saturable absorber mirror and output coupling...
Local-in-space blow-up criteria for a class of nonlinear dispersive wave equations
Novruzov, Emil
2017-11-01
This paper is concerned with blow-up phenomena for the nonlinear dispersive wave equation on the real line, ut -uxxt +[ f (u) ] x -[ f (u) ] xxx +[ g (u) + f″/(u) 2 ux2 ] x = 0 that includes the Camassa-Holm equation as well as the hyperelastic-rod wave equation (f (u) = ku2 / 2 and g (u) = (3 - k) u2 / 2) as special cases. We establish some a local-in-space blow-up criterion (i.e., a criterion involving only the properties of the data u0 in a neighborhood of a single point) simplifying and precising earlier blow-up criteria for this equation.
Dispersal of grouper larvae drives local resource sharing in a coral reef fishery
Almany, Glenn R.; Hamilton, Richard J.; Bode, Michael; Matawai, Manuai; Potuku, Tapas; Saenz Agudelo, Pablo; Planes, Serge; Berumen, Michael L.; Rhodes, Kevin L.; Thorrold, Simon R.; Russ, Garry Ronald; Jones, Geoffrey P.
2013-01-01
In many tropical nations, fisheries management requires a community-based approach because small customary marine tenure areas define the spatial scale of management [1]. However, the fate of larvae originating from a community's tenure is unknown, and thus the degree to which a community can expect their management actions to replenish the fisheries within their tenure is unclear [2, 3]. Furthermore, whether and how much larval dispersal links tenure areas can provide a strong basis for cooperative management [4, 5]. Using genetic parentage analysis, we measured larval dispersal from a single, managed spawning aggregation of squaretail coral grouper (Plectropomus areolatus) and determined its contribution to fisheries replenishment within five community tenure areas up to 33 km from the aggregation at Manus Island, Papua New Guinea. Within the community tenure area containing the aggregation, 17%-25% of juveniles were produced by the aggregation. In four adjacent tenure areas, 6%-17% of juveniles were from the aggregation. Larval dispersal kernels predict that 50% of larvae settled within 14 km of the aggregation. These results strongly suggest that both local and cooperative management actions can provide fisheries benefits to communities over small spatial scales. © 2013 Elsevier Ltd.
Dispersal of grouper larvae drives local resource sharing in a coral reef fishery
Almany, Glenn R.
2013-04-01
In many tropical nations, fisheries management requires a community-based approach because small customary marine tenure areas define the spatial scale of management [1]. However, the fate of larvae originating from a community\\'s tenure is unknown, and thus the degree to which a community can expect their management actions to replenish the fisheries within their tenure is unclear [2, 3]. Furthermore, whether and how much larval dispersal links tenure areas can provide a strong basis for cooperative management [4, 5]. Using genetic parentage analysis, we measured larval dispersal from a single, managed spawning aggregation of squaretail coral grouper (Plectropomus areolatus) and determined its contribution to fisheries replenishment within five community tenure areas up to 33 km from the aggregation at Manus Island, Papua New Guinea. Within the community tenure area containing the aggregation, 17%-25% of juveniles were produced by the aggregation. In four adjacent tenure areas, 6%-17% of juveniles were from the aggregation. Larval dispersal kernels predict that 50% of larvae settled within 14 km of the aggregation. These results strongly suggest that both local and cooperative management actions can provide fisheries benefits to communities over small spatial scales. © 2013 Elsevier Ltd.
Czech Academy of Sciences Publication Activity Database
Nakayama, H.; Jurčáková, Klára; Nagai, H.
2013-01-01
Roč. 50, č. 5 (2013), s. 503-519 ISSN 0022-3131 Institutional support: RVO:61388998 Keywords : local-scale high-resolution dispersion model * nuclear emergency response system * large-eddy simulation * spatially developing turbulent boundary layer flow Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 1.452, year: 2013
Suzuki, Tatsuya; Makyio, Hisayoshi; Ando, Hiromune; Komura, Naoko; Menjo, Masanori; Yamada, Yusuke; Imamura, Akihiro; Ishida, Hideharu; Wakatsuki, Soichi; Kato, Ryuichi; Kiso, Makoto
2014-04-01
Seleno-lactoses have been successfully synthesized as candidates for mimicking carbohydrate ligands for human galectin-9 N-terminal carbohydrate recognition domain (NCRD). Selenium was introduced into the mono- or di-saccharides using p-methylselenobenzoic anhydride (Tol2Se) as a novel selenating reagent. The TolSe-substituted monosaccharides were converted into selenoglycosyl donors or acceptors, which were reacted with coupling partners to afford seleno-lactoses. The seleno-lactoses were converted to the target compounds. The structure of human galectin-9 NCRD co-crystallized with 6-MeSe-lactose was determined with single/multi-wavelength anomalous dispersion (SAD/MAD) phasing and was similar to that of the co-crystal with natural lactose. Copyright © 2014 Elsevier Ltd. All rights reserved.
Revisit to diffraction anomalous fine structure
International Nuclear Information System (INIS)
Kawaguchi, T.; Fukuda, K.; Tokuda, K.; Shimada, K.; Ichitsubo, T.; Oishi, M.; Mizuki, J.; Matsubara, E.
2014-01-01
The diffraction anomalous fine structure method has been revisited by applying this measurement technique to polycrystalline samples and using an analytical method with the logarithmic dispersion relation. The diffraction anomalous fine structure (DAFS) method that is a spectroscopic analysis combined with resonant X-ray diffraction enables the determination of the valence state and local structure of a selected element at a specific crystalline site and/or phase. This method has been improved by using a polycrystalline sample, channel-cut monochromator optics with an undulator synchrotron radiation source, an area detector and direct determination of resonant terms with a logarithmic dispersion relation. This study makes the DAFS method more convenient and saves a large amount of measurement time in comparison with the conventional DAFS method with a single crystal. The improved DAFS method has been applied to some model samples, Ni foil and Fe 3 O 4 powder, to demonstrate the validity of the measurement and the analysis of the present DAFS method
International Nuclear Information System (INIS)
Ozaki, Toru; Amau, Toshirou; Kawata, Hiroshi; Mizuno, Kaoru; Mori, Koichi.
1997-01-01
We have carried out an X-ray intensity measurement and X-ray topography on electroded b plates of ferroelectric cesium dihydrogen phosphate, CsH 2 PO 4 (CDP), using a synchrotron radiation with a wavelength of 2.482 A above the Cs L 3 -absorption edge. We have found that integrated intensities I(150) and I(1-bar5-bar0) show an anomalously large breakdown of Friedel's law, I(150)/I(1-bar5-bar0)=10.4 at 125 K, and display a ferroelectric hysteresis loop. The hysteresis loop determines that spontaneous polarization is antiparallel to the b axes set in both ferroelectric crystal structures related by inversions. The (150) diffraction topography shows that a single domain turns into a lamellar domain structure without fractal aspects after short-circuiting the b plate. The atomic displacement associated with polarization reversal is shown in a crystal structure model of 180deg domains observed in the X-ray topography. (author)
International Nuclear Information System (INIS)
Piskorska-Hommel, E.; Holý, V.; Caha, O.; Wolska, A.; Gust, A.; Kruse, C.; Kröncke, H.; Falta, J.; Hommel, D.
2012-01-01
The extended X-ray absorption fine structure (EXAFS) and diffraction anomalous fine structure (DAFS) have been applied to investigate a local structure for the CdSe/ZnSe quantum dots grown by molecular beam epitaxy (MBE) and migration-enhanced epitaxy (MEE). The aim was to study the intermixing of Cd and Zn atoms, chemical compositions and strain induced by cap-layer. The EXAFS at the Cd K-edge and DAFS at the Se K-edge proved the intermixing of Cd and Zn atoms. The distances Cd–Se (2.61 Å) found from EXAFS and DAFS analysis for h 1 region is closer to that in bulk CdSe (2.62 Å). The DAFS analysis revealed the differences in the local structure in two investigated regions (i.e. different iso-strain volumes) on the quantum dots. It was found that the investigated areas differ in the Cd concentration. To explain the experimental results the theoretical calculation based on a full valence-force field (VFF) model was performed. The theoretical VFF model fully explains the experimental data.
Local-scale high-resolution atmospheric dispersion model using large-eddy simulation. LOHDIM-LES
International Nuclear Information System (INIS)
Nakayama, Hiromasa; Nagai, Haruyasu
2016-03-01
We developed LOcal-scale High-resolution atmospheric DIspersion Model using Large-Eddy Simulation (LOHDIM-LES). This dispersion model is designed based on LES which is effective to reproduce unsteady behaviors of turbulent flows and plume dispersion. The basic equations are the continuity equation, the Navier-Stokes equation, and the scalar conservation equation. Buildings and local terrain variability are resolved by high-resolution grids with a few meters and these turbulent effects are represented by immersed boundary method. In simulating atmospheric turbulence, boundary layer flows are generated by a recycling turbulent inflow technique in a driver region set up at the upstream of the main analysis region. This turbulent inflow data are imposed at the inlet of the main analysis region. By this approach, the LOHDIM-LES can provide detailed information on wind velocities and plume concentration in the investigated area. (author)
Theory of pairwise coupling embedded in more general local dispersion relations
International Nuclear Information System (INIS)
Fuchs, V.; Bers, A.; Harten, L.
1985-01-01
Earlier work on the mode conversion theory by Fuchs, Ko, and Bers is detailed and expanded upon, and its relation to energy conservation is discussed. Given a local dispersion relation, D(ω; k, z) = 0, describing stable waves excited at an externally imposed frequency ω, a pairwise mode-coupling event embedded therein is extracted by expanding D(k, z) around a contour k = k/sub c/(z) given by partialD/partialk = 0. The branch points of D(k, z) = 0 are the turning points of a second-order differential-equation representation. In obtaining the fraction of mode-converted energy, the connection formula and conservation of energy must be used together. Also, proper attention must be given to distinguish cases for which the coupling disappears or persists upon confluence of the branches, a property which is shown to depend on the forward (v/sub g/v/sub ph/>0) or backward (v/sub g/v/sub ph/<0) nature of the waves. Examples occurring in ion-cyclotron and lower-hybrid heating are presented, illustrating the use of the theory
Influence of local parameters on the dispersion of traffic-related pollutants within street canyons
Karra, Styliani; Malki-Epshtein, Liora; Martin Hyde Collaboration
2011-11-01
Ventilation within urban cities and street canyons and the associated air quality is a problem of increasing interest in the last decades. It is important for to minimise exposure of the population to traffic-related pollutants at street level. The residence time of pollutants within the street canyons depends on the meteorological conditions such as wind speed and direction, geometry layout and local parameters (position of traffic lane within the street). An experimental study was carried out to investigate the influence of traffic lane position on the dispersion of traffic-related pollutants within different street canyons geometries: symmetrical (equal building heights on both sides of the street), non-symmetrical (uniform building heights but lower on one side of the street) and heterogeneous (non-uniform building heights on both sides of the street) under constant meteorological conditions. Laboratory experiments were carried out within a water channel and simultaneous measurements of velocity field and concentration scalar levels within and above the street canyons using PIV and PLIF techniques. Traffic -related emissions were simulated using a line emission source. Two positions were examined for all street geometries: line emission source was placed in the centre of the street canyon; line emission source was placed off the centre of the street. TSI Incorporated.
International Nuclear Information System (INIS)
Wendin, G.
1979-01-01
The availability of tunable synchrotron radiation has made it possible systematically to perform x-ray diffraction studies in regions of anomalous scattering near absorption edges, e.g. in order to derive phase information for crystal structure determination. An overview is given of recent experimental and theoretical work and discuss the properties of the anomalous atomic scattering factor, with emphasis on threshold resonances and damping effects. The results are applied to a discussion of the very strong anomalous dispersion recently observed near the L 3 edge in a cesium complex. Also given is an overview of elements and levels where similar behavior can be expected. Finally, the influence of solid state and chemical effects on the absorption edge structure is discussed. 64 references
International Nuclear Information System (INIS)
Sandu, Irina; Lac, Christine
2003-01-01
METEO-FRANCE is presently developing a new system named PERLE which permits real time evaluation of atmospheric dispersion at local scale. This system consists in a non-hydrostatic meteorological model at mezo-scale (Meso-NH) and a particular code for the dispersion of the chemically passive pollutants. As a result of several studies performed by DP/SERV/ENV at Meteo-France, two particular codes have been retained for the dispersion module of PERLE: DIFPAR (EDF) and SPRAY (Aria Technologies). In this study, the dispersion at local scale of Kr 85 in the area of the nuclear-wastes reprocessing plant COGEMA (La Hague) has been simulated with the two dispersion models, initialised with the meteorological fields provided by Meso-NH. The simulations concern the most complete sampling campaign of Kr 85 performed in this area on 18th and 19th september 2001. The evaluation the two models performances and of the PERLE system's results for this campaign has been done by using the CTA (Atmospherical Transfer Coefficient) measured values. (authors)
Directory of Open Access Journals (Sweden)
M. Mucciarelli
2007-06-01
Full Text Available This paper presents the preliminary results analysing the correlation between local seismicity and geoelectrical, hydrogeological and geochemical signals concomitantly recorded in Basilicata Region, one of the most seismically active areas in Southern Italy. The signals were recorded by two stations: Tito and Tramutola. Tito station measures vertically the Self-Potential field (SP by an array of five no-polarizable electrodes equally spaced with the common electrode at 20 m depth as well as water-level, water-temperature and electrical-conductivity. Tramutola station measures self-potential signals in soil surface, gas flow and water temperature in a thermal-water well, as well as atmospheric barometric pressure and ambient temperature. Correlations were found between the sharp variability of the signals recorded by both stations and the seismic sequence that occurred on September 3 to 4, 2004, allowing us to link these anomalies with the tectonic evolution of the investigated area.
Directory of Open Access Journals (Sweden)
K.J.B. Ghosh
2018-01-01
Full Text Available We consider four-dimensional chiral gauge theories defined over a spacetime manifold with topology R3×S1 and periodic boundary conditions over the compact dimension. The effective gauge-field action is calculated for Abelian U(1 gauge fields Aμ(x which depend on all four spacetime coordinates (including the coordinate x4∈S1 of the compact dimension and have vanishing components A4(x (implying trivial holonomies in the 4-direction. Our calculation shows that the effective gauge-field action contains a local Chern–Simons-like term which violates Lorentz and CPT invariance. This result is established perturbatively with a generalized Pauli–Villars regularization and nonperturbatively with a lattice regularization based on Ginsparg–Wilson fermions.
Ghosh, K. J. B.; Klinkhamer, F. R.
2018-01-01
We consider four-dimensional chiral gauge theories defined over a spacetime manifold with topology R3 ×S1 and periodic boundary conditions over the compact dimension. The effective gauge-field action is calculated for Abelian U (1) gauge fields Aμ (x) which depend on all four spacetime coordinates (including the coordinate x4 ∈S1 of the compact dimension) and have vanishing components A4 (x) (implying trivial holonomies in the 4-direction). Our calculation shows that the effective gauge-field action contains a local Chern-Simons-like term which violates Lorentz and CPT invariance. This result is established perturbatively with a generalized Pauli-Villars regularization and nonperturbatively with a lattice regularization based on Ginsparg-Wilson fermions.
Generalized dispersive wave emission in nonlinear fiber optics.
Webb, K E; Xu, Y Q; Erkintalo, M; Murdoch, S G
2013-01-15
We show that the emission of dispersive waves in nonlinear fiber optics is not limited to soliton-like pulses propagating in the anomalous dispersion regime. We demonstrate, both numerically and experimentally, that pulses propagating in the normal dispersion regime can excite resonant dispersive radiation across the zero-dispersion wavelength into the anomalous regime.
International Nuclear Information System (INIS)
Kavitha, L.; Mohamadou, A.; Parasuraman, E.; Gopi, D.; Akila, N.; Prabhu, A.
2016-01-01
The nonlinear localization phenomena in ferromagnetic spin lattices have attracted a steadily growing interest and their existence has been predicted in a wide range of physical settings. We investigate the onset of modulational instability of a plane wave in a discrete ferromagnetic spin chain with physically significant higher order dispersive octupole–dipole and dipole–dipole interactions. We derive the discrete nonlinear equation of motion with the aid of Holstein–Primakoff (H–P) transformation combined with Glauber's coherent state representation. We show that the discrete ferromagnetic spin dynamics is governed by an entirely new discrete NLS model with complex coefficients not reported so far. We report the study of modulational instability (MI) of the ferromagnetic chain with long range dispersive interactions both analytically in the frame work of linear stability analysis and numerically by means of molecular dynamics (MD) simulations. Our numerical simulations explore that the analytical predictions correctly describe the onset of instability. It is found that the presence of the various exchange and dispersive higher order interactions systematically favors the local gathering of excitations and thus supports the growth of high amplitude, long-lived discrete breather (DB) excitations. We analytically compute the strongly localized odd and even modes. Further, we employ the Jacobi elliptic function method to solve the nonlinear evolution equation and an exact propagating bubble-soliton solution is explored. - Highlights: • Higher order dispersive interactions plays significant role in ferromagnetic spin chain. • The energy localization is studied both analytically and numerically. • The existence of DBs are studied under the effect of higher order dispersive interaction.
Impact of local diffusion on macroscopic dispersion in three-dimensional porous media
Dartois, Arthur; Beaudoin, Anthony; Huberson, Serge
2018-02-01
While macroscopic longitudinal and transverse dispersion in three-dimensional porous media has been simulated previously mostly under purely advective conditions, the impact of diffusion on macroscopic dispersion in 3D remains an open question. Furthermore, both in 2D and 3D, recurring difficulties have been encountered due to computer limitation or analytical approximation. In this work, we use the Lagrangian velocity covariance function and the temporal derivative of second-order moments to study the influence of diffusion on dispersion in highly heterogeneous 2D and 3D porous media. The first approach characterizes the correlation between the values of Eulerian velocity components sampled by particles undergoing diffusion at two times. The second approach allows the estimation of dispersion coefficients and the analysis of their behaviours as functions of diffusion. These two approaches allowed us to reach new results. The influence of diffusion on dispersion seems to be globally similar between highly heterogeneous 2D and 3D porous media. Diffusion induces a decrease in the dispersion in the direction parallel to the flow direction and an increase in the dispersion in the direction perpendicular to the flow direction. However, the amplification of these two effects with the permeability variance is clearly different between 2D and 3D. For the direction parallel to the flow direction, the amplification is more important in 3D than in 2D. It is reversed in the direction perpendicular to the flow direction.
DEFF Research Database (Denmark)
Hargreaves, Anna; Bailey, Susan; Laird, Robert
2015-01-01
Dispersal ability will largely determine whether species track their climatic niches during climate change, a process especially important for populations at contracting (low-latitude/low-elevation) range limits that otherwise risk extinction. We investigate whether dispersal evolution....... We simulate a species distributed continuously along a temperature gradient using a spatially explicit, individual-based model. We compare range-wide dispersal evolution during climate stability vs. directional climate change, with uniform fitness vs. fitness that declines towards range limits (RLs...... at contracting range limits is facilitated by two processes that potentially enable edge populations to experience and adjust to the effects of climate deterioration before they cause extinction: (i) climate-induced fitness declines towards range limits and (ii) local adaptation to a shifting climate gradient...
Using velocity dispersion to estimate halo mass: Is the Local Group in tension with ΛCDM?
Elahi, Pascal J.; Power, Chris; Lagos, Claudia del P.; Poulton, Rhys; Robotham, Aaron S. G.
2018-06-01
Satellite galaxies are commonly used as tracers to measure the line-of-sight (LOS)velocity dispersion (σLOS) of the dark matter halo associated with their central galaxy, and thereby to estimate the halo's mass. Recent observational dispersion estimates of the Local Group, including the Milky Way and M31, suggest σ ˜50 km s-1, which is surprisingly low when compared to the theoretical expectation of σ ˜100 km s-1 for systems of their mass. Does this pose a problem for Lambda cold dark matter (ΛCDM)? We explore this tension using the SURFS suite of N-body simulations, containing over 10000 (sub)haloes with well tracked orbits. We test how well a central galaxy's host halo velocity dispersion can be recovered by sampling σLOS of subhaloes and surrounding haloes. Our results demonstrate that σLOS is biased mass proxy. We define an optimal window in vLOS and projected distance (Dp) - 0.5 ≲ Dp/Rvir ≲ 1.0 and vLOS ≲ 0.5Vesc, where Rvir is the virial radius and Vesc is the escape velocity - such that the scatter in LOS to halo dispersion is minimized - σLOS = (0.5 ± 0.1)σv, H. We argue that this window should be used to measure LOS dispersions as a proxy for mass, as it minimises scatter in the σLOS-Mvir relation. This bias also naturally explains the results from McConnachie (2012), who used similar cuts when estimating σLOS, LG, producing a bias of σLG = (0.44 ± 0.14)σv, H. We conclude that the Local Group's velocity dispersion does not pose a problem for ΛCDM and has a mass of log M_{LG, vir}/M_{⊙}=12.0^{+0.8}_{-2.0}.
Anomalous Hall effect in polycrystalline Ni films
Guo, Zaibing
2012-02-01
We systematically studied the anomalous Hall effect in a series of polycrystalline Ni films with thickness ranging from 4 to 200 nm. It is found that both the longitudinal and anomalous Hall resistivity increased greatly as film thickness decreased. This enhancement should be related to the surface scattering. In the ultrathin films (46 nm thick), weak localization corrections to anomalous Hall conductivity were studied. The granular model, taking into account the dominated intergranular tunneling, has been employed to explain this phenomenon, which can explain the weak dependence of anomalous Hall resistivity on longitudinal resistivity as well. © 2011 Elsevier Ltd. All rights reserved.
Tyu, N. S.; Ekhilevsky, S. G.
1992-07-01
For the perfect molecular crystals the equations of the local field method (LFM) with the account of spatial dispersion are formulated. They are used to derive the expression for the crystal polarizability tensor. For the first time within the framework of this method the formula for the gyrotropy tensor of an arbitrary optically active molecular crystal is obtained. This formula is analog of well known relationships of Lorentz-Lorenz.
DEFF Research Database (Denmark)
Rasmussen, Kim; Christiansen, Peter Leth; Johansson, Magnus
1998-01-01
A one-dimensional discrete nonlinear Schrodinger (DNLS) model with the power dependence, r(-s) on the distance r, of dispersive interactions is proposed. The stationary states of the system are studied both analytically and numerically. Two kinds of trial functions, exp-like and sech-like are exp...
Directory of Open Access Journals (Sweden)
B. Aouizerats
2011-08-01
Full Text Available High resolution simulation of complex aerosol particle evolution and gaseous chemistry over an atmospheric urban area is of great interest for understanding air quality and processes. In this context, the CAPITOUL (Canopy and Aerosol Particle Interactions in the Toulouse Urban Layer field experiment aims at a better understanding of the interactions between the urban dynamics and the aerosol plumes. During a two-day Intensive Observational Period, a numerical model experiment was set up to reproduce the spatial distribution of specific particle pollutants, from the regional scales and the interactions between different cities, to the local scales with specific turbulent structures. Observations show that local dynamics depends on the day-regime, and may lead to different mesoscale dynamical structures. This study focuses on reproducing these fine scale dynamical structures, and investigate the impact on the aerosol plume dispersion. The 500-m resolution simulation manages to reproduce convective rolls at local scale, which concentrate most of the aerosol particles and can locally affect the pollutant dispersion and air quality.
International Nuclear Information System (INIS)
Sartori, E.; Schuler, W.
1992-01-01
Software and data for nuclear energy applications are acquired, tested and distributed by several information centres; in particular, relevant computer codes are distributed internationally by the OECD/NEA Data Bank (France) and by ESTSC and EPIC/RSIC (United States). This activity is coordinated among the centres and is extended outside the OECD area through an arrangement with the IAEA. This article proposes more specifically a scheme for acquiring, storing and distributing atmospheric tracer experiment data (ATE) required for verification of atmospheric dispersion models especially the most advanced ones including topographic effects and specific to the local and meso-scale. These well documented data sets will form a valuable complement to the set of atmospheric dispersion computer codes distributed internationally. Modellers will be able to gain confidence in the predictive power of their models or to verify their modelling skills. (au)
The ratio of effective building height to street width governs dispersion of local vehicle emissions
Schulte, Nico; Tan, Si; Venkatram, Akula
2015-07-01
Analysis of data collected in street canyons located in Hanover, Germany and Los Angeles, USA, suggests that street-level concentrations of vehicle-related pollutants can be estimated with a model that assumes that vertical turbulent transport of emissions dominates the governing processes. The dispersion model relates surface concentrations to traffic flow rate, the effective aspect ratio of the street, and roof level turbulence. The dispersion model indicates that magnification of concentrations relative to those in the absence of buildings is most sensitive to the aspect ratio of the street, which is the ratio of the effective height of the buildings on the street to the width of the street. This result can be useful in the design of transit oriented developments that increase building density to reduce emissions from transportation.
Comparison of the local-scale atmospheric dispersion model Cedrat with 85KR measurements
International Nuclear Information System (INIS)
Rennesson, M.; Devin, P.; Maro, D.; Fitamant, M.L.; Bouland, P.
2004-01-01
An accurate model of atmospheric dispersion of radionuclides over the complex terrain of the La Hague reprocessing plant (North Cotentin, France) has been developed by COGEMA, in partnership with Paris VI University. This model, called CEDRAT 1.0.1 (operational since October 2002), takes into account areas typically outside the validity limits of Gaussian models: relief and building influence, short-distance (beyond 500 m from the release point) and stable atmospheric conditions. The modelling tool is based on an original method: a 2D-meshed model for flow resolution at permanent rate in the prevailing wind direction, and a 3D description of the dispersion phenomena, taking into account wet and dry deposits, at permanent or transitory rate. This leads to an effective compromise between rapidity (45 min on a 6000 nodes grid, with a standard PC), robustness and accuracy, coupled with a user-friendly interface. Primarily the validation process consisted of a comparison with the 3D complex dispersion reference model MERCURE, developed by EDF. Then, MERCURE and CEDRAT results were compared on real release scenario basis, for which actual meteorological conditions and tracer data collected at monitoring stations around the site were known. To enlarge this validation process, a second level of comparison was made in collaboration with a IRSN Cherbourg team, through different field experiments, which provided both ground and elevated level measurements (collected with a captive balloon), for different stability classes of the atmosphere. The plume tracer is krypton 85, an inert gas released from a height of 100 m. Thus, the aim of this paper is to present the original method to describe short distance dispersion over complex terrain and its validation enrichment for stability conditions and areas not yet observed, through wind and cross-wind Atmospheric Transfer Coefficients comparisons, at both ground and elevated levels. (author)
Directory of Open Access Journals (Sweden)
E. S. Taheri
2012-12-01
Full Text Available Study of liquid behavior in an expanded bed adsorption (EBA system is important for understanding, modeling and predicting nanobioproduct/biomolecule adsorption performance in such processes. In this work, in order to analyze the local axial dispersion parameters, simple custom NBG (Nano Biotechnology Group expanded bed columns with 10 and 26 mm inner diameter were modified by insertion of sampling holes. Based on this configuration, the particles and liquid can be withdrawn directly from various axial positions of the columns. Streamline DEAE particles were used as solid phase in this work. The effects of factors such as liquid velocity, viscosity, settled bed height and column diameter on the hydrodynamic parameters were investigated. Local bed voidages in different axial bed positions were measured by a direct procedure within the column with 26 mm diameter. Increasing trend of voidage with velocity at a certain position of the bed and with bed height at a certain degree of expansion was observed. Residence time distribution (RTD analysis at various bed points showed approximately uniform hydrodynamic behavior in the column with 10 mm diameter while a decreasing trend of mixing/dispersion along the bed height at a certain degree of expansion was seen in the column with 26 mm diameter. Also lower mixing/dispersion occured in the smaller diameter column. Finally, a combination of two empirical correlations proposed by Richardson-Zaki and Tong-Sun was successfully employed for identification of the bed voidage at various bed heights (RSSE=99.9%. Among the empirical correlations presented in the literatures for variation of the axial dispersion coefficient, the Yun correlation gave good agreement with our experimental data (RSSE=87% in this column.
The particulate matter dispersion studies from a local palm oil mill
International Nuclear Information System (INIS)
Abdullah, L.C.; Wong, L. L.; Amnorzahira, A.; Sa'ari, M.; Abdul Rashid, M. S.; Salmiaton Ali
2006-01-01
The appearance of industrial emissions and the degradation of scenic vistas are two characteristics of air pollution that humans object. Reduction in visibility suggests worsening pollution levels. The emissions from mobile source and stationary source are the major source of air pollutions contribution in Malaysia. Suspended particulate matter (SPM). The consequence of increasing the particulate concentrations, the particulate matter dissolves with vapour and grows into droplets when the humidity exceeds approximately 70% and causing opaque situation know as haze. This work focuses on the dispersion particulate matter from palm oil mill. The data obtained serves the purpose of modeling the transport of particulate matter for obtaining permits and prevention of significant deterioration (PSD) to the environment. Gaussian Plume Model from a point source, subject to various atmospheric conditions is used to calculate particulate matter concentration then display the distribution of plume dispersion using geographic information system (GIS). The calculated particulate matter concentration is evaluated using Transilient Matrice function. Atmospheric Stability, mixing height, wind direction, wind speed, natural and artificial features play an important role in dispersion process. High concentration area exhibits immediately under prevailing wind direction. (Author)
Spatial dispersion effects upon local excitation of extrinsic plasmons in a graphene micro-disk
Mencarelli, D.; Bellucci, S.; Sindona, A.; Pierantoni, L.
2015-11-01
Excitation of surface plasmon waves in extrinsic graphene is studied using a full-wave electromagnetic field solver as analysis engine. Particular emphasis is placed on the role played by spatial dispersion due to the finite size of the two-dimensional material at the micro-scale. A simple instructive set up is considered where the near field of a wire antenna is held at sub-micrometric distance from a disk-shaped graphene patch. The key-input of the simulation is the graphene conductivity tensor at terahertz frequencies, being modeled by the Boltzmann transport equation for the valence and conduction electrons at the Dirac points (where a linear wave-vector dependence of the band energies is assumed). The conductivity equation is worked out in different levels of approximations, based on the relaxation time ansatz with an additional constraint for particle number conservation. Both drift and diffusion currents are shown to significantly contribute to the spatially dispersive anisotropic features of micro-scale graphene. More generally, spatial dispersion effects are predicted to influence not only plasmon propagation free of external sources, but also typical scanning probe microscopy configurations. The paper sets the focus on plasmon excitation phenomena induced by near field probes, being a central issue for the design of optical devices and photonic circuits.
Fractional power-law spatial dispersion in electrodynamics
International Nuclear Information System (INIS)
Tarasov, Vasily E.; Trujillo, Juan J.
2013-01-01
Electric fields in non-local media with power-law spatial dispersion are discussed. Equations involving a fractional Laplacian in the Riesz form that describe the electric fields in such non-local media are studied. The generalizations of Coulomb’s law and Debye’s screening for power-law non-local media are characterized. We consider simple models with anomalous behavior of plasma-like media with power-law spatial dispersions. The suggested fractional differential models for these plasma-like media are discussed to describe non-local properties of power-law type. -- Highlights: •Plasma-like non-local media with power-law spatial dispersion. •Fractional differential equations for electric fields in the media. •The generalizations of Coulomb’s law and Debye’s screening for the media
Application of energy-dispersive XRF technique in the hydrometallurgy study of local zircon
International Nuclear Information System (INIS)
Meor Yusoff Sulaiman; Kamaruddin Hussin; Azizan Aziz
1996-01-01
In this study, energy-dispersive X-ray Fluorescence (EDXR-F) was used to analyse the elemental composition of the starting zircon mineral associated elements in the leaching solution. Besides analysing the major elements i.e. of zirconium, silicon and hafnium, trace elemental analysis for iron, titanium and the naturally occurring radioactive element thorium and uranium are important in establishing the grades of Malaysian zircon. The technique was also used in determine the optimum conditions for zirconium and hafnium recovery during the leaching process
Local study of pollutants dispersion by a real time tracer method
International Nuclear Information System (INIS)
Faivre-Pierret, R.X.; Sestier-Carlin, R.; Berne, P.
1992-01-01
It is possible to use a Gaussian mathematical model of atmospheric dispersion for calculating atmospheric transfer coefficient (ATC) in long range model, but for proximity models, an experimental model using a tracer technic has to take in account ground effects and natural or artificial obstacles. SF 6 tracer method gives the true plume ground trace in real time. The measured ATC shows a larger ground trace, lower concentration in the axis, and a displacement of the maximum concentration with regard to wind axis in comparison with the calculated ATC. (A.B.). 14 refs., 4 figs., 1 tab
Directory of Open Access Journals (Sweden)
Nicholas John Deacon
Full Text Available Quercus oleoides Cham. and Schlect., tropical live oak, is a species of conservation importance in its southern range limit of northwestern Costa Rica. It occurs in high-density stands across a fragmented landscape spanning a contrasting elevation and precipitation gradient. We examined genetic diversity and spatial genetic structure in this geographically isolated and genetically distinct population. We characterized population genetic diversity at 11 nuclear microsatellite loci in 260 individuals from 13 sites. We monitored flowering time at 10 sites, and characterized the local environment in order to compare observed spatial genetic structure to hypotheses of isolation-by-distance and isolation-by-environment. Finally, we quantified pollen dispersal distances and tested for local adaptation through a reciprocal transplant experiment in order to experimentally address these hypotheses.High genetic diversity is maintained in the population and the genetic variation is significantly structured among sampled sites. We identified 5 distinct genetic clusters and average pollen dispersal predominately occurred over short distances. Differences among sites in flowering phenology and environmental factors, however, were not strictly associated with genetic differentiation. Growth and survival of upland and lowland progeny in their native and foreign environments was expected to exhibit evidence of local adaptation due to the more extreme dry season in the lowlands. Seedlings planted in the lowland garden experienced much higher mortality than seedlings in the upland garden, but we did not identify evidence for local adaptation.Overall, this study indicates that the Costa Rican Q. oleoides population has a rich population genetic history. Despite environmental heterogeneity and habitat fragmentation, isolation-by-distance and isolation-by-environment alone do not explain spatial genetic structure. These results add to studies of genetic structure by
Deacon, Nicholas John; Cavender-Bares, Jeannine
2015-01-01
Quercus oleoides Cham. and Schlect., tropical live oak, is a species of conservation importance in its southern range limit of northwestern Costa Rica. It occurs in high-density stands across a fragmented landscape spanning a contrasting elevation and precipitation gradient. We examined genetic diversity and spatial genetic structure in this geographically isolated and genetically distinct population. We characterized population genetic diversity at 11 nuclear microsatellite loci in 260 individuals from 13 sites. We monitored flowering time at 10 sites, and characterized the local environment in order to compare observed spatial genetic structure to hypotheses of isolation-by-distance and isolation-by-environment. Finally, we quantified pollen dispersal distances and tested for local adaptation through a reciprocal transplant experiment in order to experimentally address these hypotheses. High genetic diversity is maintained in the population and the genetic variation is significantly structured among sampled sites. We identified 5 distinct genetic clusters and average pollen dispersal predominately occurred over short distances. Differences among sites in flowering phenology and environmental factors, however, were not strictly associated with genetic differentiation. Growth and survival of upland and lowland progeny in their native and foreign environments was expected to exhibit evidence of local adaptation due to the more extreme dry season in the lowlands. Seedlings planted in the lowland garden experienced much higher mortality than seedlings in the upland garden, but we did not identify evidence for local adaptation. Overall, this study indicates that the Costa Rican Q. oleoides population has a rich population genetic history. Despite environmental heterogeneity and habitat fragmentation, isolation-by-distance and isolation-by-environment alone do not explain spatial genetic structure. These results add to studies of genetic structure by examining a common
Gim, Jungsoo; Won, Sungho; Park, Taesung
2016-10-01
High throughput sequencing technology in transcriptomics studies contribute to the understanding of gene regulation mechanism and its cellular function, but also increases a need for accurate statistical methods to assess quantitative differences between experiments. Many methods have been developed to account for the specifics of count data: non-normality, a dependence of the variance on the mean, and small sample size. Among them, the small number of samples in typical experiments is still a challenge. Here we present a method for differential analysis of count data, using conditional estimation of local pooled dispersion parameters. A comprehensive evaluation of our proposed method in the aspect of differential gene expression analysis using both simulated and real data sets shows that the proposed method is more powerful than other existing methods while controlling the false discovery rates. By introducing conditional estimation of local pooled dispersion parameters, we successfully overcome the limitation of small power and enable a powerful quantitative analysis focused on differential expression test with the small number of samples.
Energy Technology Data Exchange (ETDEWEB)
Klanderud, K.; Totland, Oe. [Norwegian Univ. of Life Science, Dept. of Ecology and Natural Resource Management, Aas (Norway)
2007-08-15
Most studies on factors determining diversity are conducted in temperate or warm regions, whereas studies in climatically harsh and low productivity areas, such as alpine regions, are rare. We examined the relative roles of seed availability and different biotic and abiotic factors for the diversity of an alpine plant community in southern Norway. Furthermore, because climate warming is predicted to be an important driver of alpine species diversity, we assessed how the relative impacts of dispersal and local interactions on diversity might change under experimental warming (open top chambers, OTCs). Addition of seeds from 27 regional species increased community diversity. The establishment of the species was negatively related both to the diversity of the existing system and the cover of the abundant dwarf shrub Dryas octopetala. These results show that both species dispersal limitation and local biotic interactions are important factors for alpine plant community diversity. Despite relatively harsh environmental conditions and low productivity, competition from the resident vegetation appeared to have a greater role for species establishment and diversity than facilitation and experimental warming. Higher temperature appeared to increase the negative relationship between resident species diversity and species establishment. This may suggest that climate warming can increase the role of interspecific competition for alpine plant community structure, and thus alter the long-term effects of biotic interactions on diversity. (au)
Compactness of viral genomes: effect of disperse and localized random mutations
Lošdorfer Božič, Anže; Micheletti, Cristian; Podgornik, Rudolf; Tubiana, Luca
2018-02-01
Genomes of single-stranded RNA viruses have evolved to optimize several concurrent properties. One of them is the architecture of their genomic folds, which must not only feature precise structural elements at specific positions, but also allow for overall spatial compactness. The latter was shown to be disrupted by random synonymous mutations, a disruption which can consequently negatively affect genome encapsidation. In this study, we use three mutation schemes with different degrees of locality to mutate the genomes of phage MS2 and Brome Mosaic virus in order to understand the observed sensitivity of the global compactness of their folds. We find that mutating local stretches of their genomes’ sequence or structure is less disruptive to their compactness compared to inducing randomly-distributed mutations. Our findings are indicative of a mechanism for the conservation of compactness acting on a global scale of the genomes, and have several implications for understanding the interplay between local and global architecture of viral RNA genomes.
Energy Technology Data Exchange (ETDEWEB)
Graber, W.K.; Buerki, D. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)
1997-06-01
In the framework of the project `WINDBANK unteres Aaretal` local winds over complex terrain were measured over a 4 month period and a cluster analysis is used to identify 13 different typical wind fields. A subset of representative stations is established to identify the classes for future applications in emergency planning. (author) 4 figs., 3 refs.
Zhao, K.; Golias, E.; Zhang, Q. H.; Krivenkov, M.; Jesche, A.; Gu, L.; Rader, O.; Mazin, I. I.; Gegenwart, P.
2018-03-01
We have synthesized single crystals of Dirac semimetal candidates A ZnBi2 with A =Ba and Sr. In contrast to A =Sr , the Ba material displays a local Zn vacancy ordering, which makes the observation of quantum oscillations in out-of-plane magnetic fields possible. As a Dirac semimetal candidate, BaZnBi2 exhibits a small cyclotron electron mass, high quantum mobility, and nontrivial Berry phases. Three Dirac dispersions are observed by angle-resolved photoemission spectroscopy and identified by first-principles band-structure calculations. Compared to A Mn(Bi/Sb) 2 systems which host Mn magnetic moments, BaZnBi2 acts as a nonmagnetic analog to investigate the intrinsic properties of Dirac fermions in this structure family.
Anomalous top magnetic couplings
Indian Academy of Sciences (India)
2012-11-09
Nov 9, 2012 ... Corresponding author. E-mail: remartinezm@unal.edu.co. Abstract. The real and imaginary parts of the one-loop electroweak contributions to the left and right tensorial anomalous couplings of the tbW vertex in the Standard Model (SM) are computed. Keywords. Top; anomalous. PACS Nos 14.65.Ha; 12.15 ...
International Nuclear Information System (INIS)
Boman, C.
1997-01-01
The decided phasing out of nuclear power and the goal of reducing CO 2 emissions from fossil fuels causes a substantial estimated increase in the use of biomass fuels for energy production. Thus, a significant shift from small scale heating generated by electricity or fuel oil to biomass fuels is desirable. If a drastic deterioration of the local air quality is to be avoided, a reduction of today's emission limits is necessary. The objective of this report was therefore to describe the use of biomass fuels and small scale pellet fuel combustion, to make a theoretical study of the effects of increased pellets heating on the air quality in a residential area, and to discuss necessary emission limits for small biomass fuel plants. The general description is based on literature studies. In the theoretical study, several different dispersion model calculations were performed using the computer program Dispersion 1.1.0. The contents of tar and total hydrocarbons (THC) in the air were calculated for different scenarios with conversion from electricity to pellets and with different pellet plant performance. A sensitivity analysis was performed with additional variables and dispersion calculations according to an underlying statistical experimental design. The modeling and design computer program MODDE was used to facilitate design, evaluation and illustration of the calculated results. The results show that a substantial increase in the use of small scale pellets heating with worst calculated plant performance, will lead to a drastic increase of the content of hydrocarbons in the air. Thus, with best available performance, the content only increases marginally. Conversion from electricity to pellets, plant performance and time of year were the most influential variables. Also conversion from wood to pellets showed a significant effect, despite the small number of wood heated houses within the studied area. If a significant deterioration of the air quality is to be avoided
Rationality of the anomalous dimensions in N=4 SYM theory
International Nuclear Information System (INIS)
Genovese, Luigi; Stanev, Yassen S.
2005-01-01
We reconsider the general constraints on the perturbative anomalous dimensions in conformal invariant QFT and in particular in N=4 SYM with gauge group SU(N). We show that all the perturbative corrections to the anomalous dimension of a renormalized gauge invariant local operator can be written as polynomials in its one loop anomalous dimension. In the N=4 SYM theory the coefficients of these polynomials are rational functions of the number of colours N
Connection between recurrence time statistics and anomalous transport
International Nuclear Information System (INIS)
Zaslavsky, G.M.; Tippett, M.K.
1991-01-01
For a model stationary flow with hexagonal symmetry, the recurrence time statistics are studied. The model has been shown to have a sharp transition from normal to anomalous transport. Here it is shown that this transition is accompanied by a correspondent change of the recurrence time statistics from normal to anomalous. The latter one displays the existence of a power tail. Recurrence time statistics provide a local measurement of anomalous transport that is of practical interest
Anomalous diffusion in a dynamical optical lattice
Zheng, Wei; Cooper, Nigel R.
2018-02-01
Motivated by experimental progress in strongly coupled atom-photon systems in optical cavities, we study theoretically the quantum dynamics of atoms coupled to a one-dimensional dynamical optical lattice. The dynamical lattice is chosen to have a period that is incommensurate with that of an underlying static lattice, leading to a dynamical version of the Aubry-André model which can cause localization of single-particle wave functions. We show that atomic wave packets in this dynamical lattice generically spread via anomalous diffusion, which can be tuned between superdiffusive and subdiffusive regimes. This anomalous diffusion arises from an interplay between Anderson localization and quantum fluctuations of the cavity field.
International Nuclear Information System (INIS)
Steele, S.R.
1984-01-01
Anomalous soil-radon activity, including several spike-like surges over periods of 5, 2, and 2 1/2 months, and a year-long declining trend, preceded the most significant earthquakes of the central mid-continental region of North America during 1981 and early 1984. The observations of these events provide further evidence of (a) the existence of soil-radon anomalies precursory to the larger earthquakes in this intraplate region, (b) the utility of such anomalies in anticipating events of small to moderate magnitudes for the region, and (c) the occurrence of regional-scale strain events prior to some of the larger mid-continental earthquakes. A very recent radon anomaly, the strongest yet to be detected in the seven years of monitoring in the mid-continental region, occurred in the New Madrid seismic zone from mid-February through mid-June 1984. A 4.0 earthquake occurred one month after a peak in the radon activity. The amplitude and duration of the anomaly suggest that a significant change in the state of stress or strain may have occurred in the mid-continental region during 1984. (Auth.)
Anomalous gauge theories revisited
International Nuclear Information System (INIS)
Matsui, Kosuke; Suzuki, Hiroshi
2005-01-01
A possible formulation of chiral gauge theories with an anomalous fermion content is re-examined in light of the lattice framework based on the Ginsparg-Wilson relation. It is shown that the fermion sector of a wide class of anomalous non-abelian theories cannot consistently be formulated within this lattice framework. In particular, in 4 dimension, all anomalous non-abelian theories are included in this class. Anomalous abelian chiral gauge theories cannot be formulated with compact U(1) link variables, while a non-compact formulation is possible at least for the vacuum sector in the space of lattice gauge fields. Our conclusion is not applied to effective low-energy theories with an anomalous fermion content which are obtained from an underlying anomaly-free theory by sending the mass of some of fermions to infinity. For theories with an anomalous fermion content in which the anomaly is cancelled by the Green-Schwarz mechanism, a possibility of a consistent lattice formulation is not clear. (author)
International Nuclear Information System (INIS)
Eggert, F.; Heckel, J.
1986-01-01
The method realized in program QMA-184 of the energy dispersive X-Ray-Microanalyzer EDR-184 for quantitative spectra analyzing of bulk materials by using local peak-to-background ratios is described in detail. The authors demonstrate efficiency and limitations of the used method by discussion of experimental results. (author)
Anomalous refraction of light colors by a metamaterial prism.
Silveirinha, Mário G
2009-05-15
A prism of glass separates white light into its spectral components in such a manner that colors associated with shorter wavelengths are more refracted than the colors associated with longer wavelengths. Here, we demonstrate that this property is not universal, and that a lossless metamaterial prism with a suitable microstructure may enable a broadband regime of anomalous dispersion, where the spectral components of light are separated in an unconventional way, so that "violet light" is less refracted than "red light." This phenomenon is fundamentally different from conventional anomalous dispersion effects, which are invariably accompanied by significant loss and are typically very narrow band.
International Nuclear Information System (INIS)
Gasparian, A.P.
1984-01-01
Results are presented from a bubble chamber experiment to search for anomalous mean free path (MFP) phenomena for secondary multicharged fragments (Zsub(f)=5 and 6) of the beam carbon nucleus at 4.2 GeV/c per nucleon. A total of 50000 primary interactions of carbon with propane (C 3 H 8 ) were created. Approximately 6000 beam tragments with charges Zsub(f)=5 and 6 were analyzed in detail to find out an anomalous decrease of MFP. The anomaly is observed only for secondary 12 C nuclei
Energy Technology Data Exchange (ETDEWEB)
Zarycz, M. Natalia C., E-mail: mnzarycz@gmail.com; Provasi, Patricio F., E-mail: patricio@unne.edu.ar [Department of Physics, University of Northeastern - CONICET, Av. Libertad 5500, Corrientes W3404AAS (Argentina); Sauer, Stephan P. A., E-mail: sauer@kiku.dk [Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø (Denmark)
2014-10-21
We discuss the effect of electron correlation on the unexpected differential sensitivity (UDS) in the {sup 1}J(C–H) coupling constant of CH{sub 4} using a decomposition into contributions from localized molecular orbitals and compare with the {sup 1}J(N–H) coupling constant in NH{sub 3}. In particular, we discuss the well known fact that uncorrelated coupled Hartree-Fock (CHF) calculations are not able to reproduce the UDS in methane. For this purpose we have implemented for the first time a localized molecular orbital analysis for the second order polarization propagator approximation with coupled cluster singles and doubles amplitudes—SOPPA(CCSD) in the DALTON program. Comparing the changes in the localized orbital contributions at the correlated SOPPA and SOPPA(CCSD) levels and at the uncorrelated CHF level, we find that the latter overestimates the effect of stretching the bond between the coupled atoms on the contribution to the coupling from the localized bonding orbital between these atoms. This disturbs the subtle balance between the molecular orbital contributions, which lead to the UDS in methane.
Anomalous and resonance small-angle scattering
International Nuclear Information System (INIS)
Epperson, J.E.; Thiyagarajan, P.
1988-01-01
Significant changes in the small-angle scattered intensity can be induced by making measurements with radiation close to an absorption edge of an appropriate atomic species contained in the sample. These changes can be related quantitatively to the real and imaginary anomalous-dispersion terms for the scattering factor (X-rays) or scattering length (neutrons). The physics inherent in these anomalous-dispersion terms is first discussed before consideration of how they enter the relevant scattering theory. Two major areas of anomalous-scattering research have emerged; macromolecules in solution and unmixing of metallic alloys. Research in each area is reviewed, illustrating both the feasibility and potential of these techniques. All the experimental results reported to date have been obtained with X-rays. However, it is pointed out that the formalism is the same for the analog experiment with neutrons, and a number of suitable isotopes exist which exhibit resonance in an accessible range of energy. Potential applications of resonance small-angle neutron scattering are discussed. (orig.)
'Complexity' and anomalous transport in space plasmas
International Nuclear Information System (INIS)
Chang, Tom; Wu Chengchin
2002-01-01
'Complexity' has become a hot topic in nearly every field of modern physics. Space plasma is of no exception. In this paper, it is demonstrated that the sporadic and localized interactions of magnetic coherent structures are the origin of 'complexity' in space plasmas. The intermittent localized interactions, which generate the anomalous diffusion, transport, and evolution of the macroscopic state variables of the overall dynamical system, may be modeled by a triggered (fast) localized chaotic growth equation of a set of relevant order parameters. Such processes would generally pave the way for the global system to evolve into a 'complex' state of long-ranged interactions of fluctuations, displaying the phenomenon of forced and/or self-organized criticality. An example of such type of anomalous transport and evolution in a sheared magnetic field is provided via two-dimensional magnetohydrodynamic simulations. The coarse-grained dissipation due to the intermittent triggered interactions among the magnetic coherent structures induces a 'fluctuation-induced nonlinear instability' that reconfigures the sheared magnetic field into an X-point magnetic geometry (in the mean field sense), leading to the anomalous acceleration of the magnetic coherent structures. A phenomenon akin to such type of anomalous transport and acceleration, the so-called bursty bulk flows, has been commonly observed in the plasma sheet of the Earth's magnetotail
Diffusion coefficient for anomalous transport
International Nuclear Information System (INIS)
1986-01-01
A report on the progress towards the goal of estimating the diffusion coefficient for anomalous transport is given. The gyrokinetic theory is used to identify different time and length scale inherent to the characteristics of plasmas which exhibit anomalous transport
Czech Academy of Sciences Publication Activity Database
Nagaosa, N.; Sinova, Jairo; Onoda, S.; MacDonald, A. H.; Ong, N. P.
2010-01-01
Roč. 82, č. 2 (2010), s. 1539-1592 ISSN 0034-6861 Institutional research plan: CEZ:AV0Z10100521 Keywords : anomalous Hall effect * spintronics Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 51.695, year: 2010
Anomalous vacuum expectation values
International Nuclear Information System (INIS)
Suzuki, H.
1986-01-01
The anomalous vacuum expectation value is defined as the expectation value of a quantity that vanishes by means of the field equations. Although this value is expected to vanish in quantum systems, regularization in general produces a finite value of this quantity. Calculation of this anomalous vacuum expectation value can be carried out in the general framework of field theory. The result is derived by subtraction of divergences and by zeta-function regularization. Various anomalies are included in these anomalous vacuum expectation values. This method is useful for deriving not only the conformal, chiral, and gravitational anomalies but also the supercurrent anomaly. The supercurrent anomaly is obtained in the case of N = 1 supersymmetric Yang-Mills theory in four, six, and ten dimensions. The original form of the energy-momentum tensor and the supercurrent have anomalies in their conservation laws. But the modification of these quantities to be equivalent to the original one on-shell causes no anomaly in their conservation laws and gives rise to anomalous traces
Temperature dependent anomalous statistics
International Nuclear Information System (INIS)
Das, A.; Panda, S.
1991-07-01
We show that the anomalous statistics which arises in 2 + 1 dimensional Chern-Simons gauge theories can become temperature dependent in the most natural way. We analyze and show that a statistic's changing phase transition can happen in these theories only as T → ∞. (author). 14 refs
Kinetic studies of anomalous transport
International Nuclear Information System (INIS)
Tang, W.M.
1990-11-01
Progress in achieving a physics-based understanding of anomalous transport in toroidal systems has come in large part from investigations based on the proposition that low frequency electrostatic microinstabilities are dominant in the bulk (''confinement'') region of these plasmas. Although the presence here of drift-type modes dependent on trapped particle and ion temperature gradient driven effects appears to be consistent with a number of important observed confinement trends, conventional estimates for these instabilities cannot account for the strong current (I p ) and /or q-scaling frequently found in empirically deduced global energy confinement times for auxiliary-heated discharges. The present paper deals with both linear and nonlinear physics features, ignored in simpler estimates, which could introduce an appreciable local dependence on current. It is also pointed out that while the thermal flux characteristics of drift modes have justifiably been the focus of experimental studies assessing their relevance, other transport properties associated with these microinstabilities should additionally be examined. Accordingly, the present paper provides estimates and discusses the significance of anomalous energy exchange between ions and electrons when fluctuations are present. 19 refs., 3 figs
Czech Academy of Sciences Publication Activity Database
Hensen, A.; Loubet, B.; Mosquera, J.; van den Bulk, W. C. M.; Erisman, J. W.; Daemmgen, U.; Milford, C.; Loepmeier, F. J.; Cellier, P.; Mikuška, Pavel; Sutton, M. A.
2009-01-01
Roč. 6, č. 12 (2009), s. 2847-2860 ISSN 1726-4170 Institutional research plan: CEZ:AV0Z40310501 Keywords : NH3 livestock farm emissions * concentration measurement * atmospheric dispersion Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.246, year: 2009 http://www.biogeosciences.net/6/2847/2009/
Fallah-Shorshani, Masoud; Shekarrizfard, Maryam; Hatzopoulou, Marianne
2017-10-01
Dispersion of road transport emissions in urban metropolitan areas is typically simulated using Gaussian models that ignore the turbulence and drag induced by buildings, which are especially relevant for areas with dense downtown cores. To consider the effect of buildings, street canyon models are used but often at the level of single urban corridors and small road networks. In this paper, we compare and validate two dispersion models with widely varying algorithms, across a modelling domain consisting of the City of Montreal, Canada accounting for emissions of more 40,000 roads. The first dispersion model is based on flow decomposition into the urban canopy sub-flow as well as overlying airflow. It takes into account the specific height and geometry of buildings along each road. The second model is a Gaussian puff dispersion model, which handles complex terrain and incorporates three-dimensional meteorology, but accounts for buildings only through variations in the initial vertical mixing coefficient. Validation against surface observations indicated that both models under-predicted measured concentrations. Average weekly exposure surfaces derived from both models were found to be reasonably correlated (r = 0.8) although the Gaussian dispersion model tended to underestimate concentrations around the roadways compared to the street canyon model. In addition, both models were used to estimate exposures of a representative sample of the Montreal population composed of 1319 individuals. Large differences were noted whereby exposures derived from the Gaussian puff model were significantly lower than exposures derived from the street canyon model, an expected result considering the concentration of population around roadways. These differences have large implications for the analyses of health effects associated with NO2 exposure.
Dispersion engineering for integrated nanophotonics
Vanbésien, Olivier
2014-01-01
This book shows how dispersion engineering in two dimensional dielectric photonic crystals can provide new effects for the precise control of light propagation for integrated nanophotonics.Dispersion engineering in regular and graded photonic crystals to promote anomalous refraction effects is studied from the concepts to experimental demonstration via nanofabrication considerations. Self collimation, ultra and negative refraction, second harmonic generation, mirage and invisibility effects which lead to an unprecedented control of light propagation at the (sub-)wavelength scale for the
Causal vs. analytic constraints on anomalous quartic gauge couplings
International Nuclear Information System (INIS)
Vecchi, L.
2007-01-01
We derive one loop constraints on the anomalous quartic gauge couplings using a general non-forward dispersion relation for the elastic scattering amplitude of two longitudinally polarized vector bosons. We show that for exactly chiral theories more stringent bounds can be obtained by the assumption that the underlying theory satisfies the causality principle of Special Relativity
Causal vs. Analytic constraints on anomalous quartic gauge couplings
Vecchi, Luca
2007-01-01
We derive one loop constraints on the anomalous quartic gauge couplings using a general non-forward dispersion relation for the elastic scattering amplitude of two longitudinally polarized vector bosons. We compare this result with another one derived by the assumption that the underlying theory satisfies the causality principle of Special Relativity and show that this latter is more constraining.
Anomalous Lorentz and CPT violation
Klinkhamer, F. R.
2018-01-01
If there exists Lorentz and CPT violation in nature, then it is crucial to discover and understand the underlying mechanism. In this contribution, we discuss one such mechanism which relies on four-dimensional chiral gauge theories defined over a spacetime manifold with topology ℛ3 × S 1 and periodic spin structure for the compact dimension. It can be shown that the effective gauge-field action contains a local Chern-Simons-like term which violates Lorentz and CPT invariance. For arbitrary Abelian U(1) gauge fields with trivial holonomies in the compact direction, this anomalous Lorentz and CPT violation has recently been established perturbatively with a Pauli-Villars-type regularization and nonperturbatively with a lattice regularization based on Ginsparg-Wilson fermions.
Anomalous transport in tokamaks
International Nuclear Information System (INIS)
Wootton, A.J.
1989-01-01
A review is presented of what is known about anomalous transport in tokamaks. It is generally thought that this anomalous transport is the result of fluctuations in various plasma parameters. In the plasma edge detailed measurements of the quantities required to directly determine the fluctuation driven fluxes are available. The total flux of particles is well explained by the measured electrostatic fluctuation driven flux. However, a satisfactory model to explain the origin of the fluctuations has not been identified. The processes responsible for determining the edge energy flux are less clear, but electrostatic convection plays an important part. In the confinement region experimental observations are presently restricted to measurements of density and potential fluctuations and their correlations. The characteristics of the measured fluctuations are discussed and compared with the predictions of various models. Comparisons between measured particle, electron heat and ion heat fluxes, and those fluxes predicted to result from the measured fluctuations, are made. Magnetic fluctuations is discussed
International Nuclear Information System (INIS)
Karmanov, V.A.
1983-01-01
Experimental data are given, the status of anomalon problem is discussed, theoretical approaches to this problem are outlined. Anomalons are exotic objects formed following fragmentation of nuclei-targets under the effect of nuclei - a beam at the energy of several GeV/nucleon. These nuclear fragments have an anomalously large cross section of interaction and respectively, small free path, considerably shorter than primary nuclei have. The experimental daa are obtained in accelerators following irradiation of nuclear emulsions by 16 O, 56 Fe, 40 Ar beams, as well as propane by 12 C beams. The experimental data testify to dependence of fragment free path on the distance L from the point of the fragment formation. A decrease in the fragment free path is established more reliably than its dependence on L. The problem of the anomalon existence cannot be yet considered resolved. Theoretical models suggested for explanation of anomalously large cross sections of nuclear fragment interaction are variable and rather speculative
Markey, Kathryn L; Abdo, Dave A; Evans, Scott N; Bosserelle, Cyprien
2016-01-01
In 2011 the first recorded bleaching event for the high latitude Houtman Abrolhos Islands (HAI) coral communities was documented. This bleaching event highlighted the question of whether a supply of 'heat tolerant' coral recruits from the tropical north would be sufficient to provide a level of resistance for these reefs to future warming events. Using Lagrangian modelling we showed that due to its regional isolation, large-scale larval input from potential tropical northern source populations to the HAI is unlikely, despite the southward flowing Leeuwin current. Successful recruitment to artificial substrates was recorded following the bleaching event. However, this was negligible (0.4 ± 0.1 recruits per tile) compared to 2013 post impact recruitment (128.8 ± 15.8 recruits per tile). Our data therefore provides preliminary evidence suggesting that the connectivity of the HAI with coral communities in the north is limited, and population maintenance and recovery is likely driven primarily by self-recruitment. Given the low thermal tolerance of the HAI coral communities, the dominance of Acropora, and the apparent reliance on self-recruitment, an increased frequency of thermally anomalous conditions at the HAI (such as experienced in 2011) has the potential to reduce the long-term stability of the HAI coral populations and species that depend upon them.
Directory of Open Access Journals (Sweden)
Kathryn L Markey
Full Text Available In 2011 the first recorded bleaching event for the high latitude Houtman Abrolhos Islands (HAI coral communities was documented. This bleaching event highlighted the question of whether a supply of 'heat tolerant' coral recruits from the tropical north would be sufficient to provide a level of resistance for these reefs to future warming events. Using Lagrangian modelling we showed that due to its regional isolation, large-scale larval input from potential tropical northern source populations to the HAI is unlikely, despite the southward flowing Leeuwin current. Successful recruitment to artificial substrates was recorded following the bleaching event. However, this was negligible (0.4 ± 0.1 recruits per tile compared to 2013 post impact recruitment (128.8 ± 15.8 recruits per tile. Our data therefore provides preliminary evidence suggesting that the connectivity of the HAI with coral communities in the north is limited, and population maintenance and recovery is likely driven primarily by self-recruitment. Given the low thermal tolerance of the HAI coral communities, the dominance of Acropora, and the apparent reliance on self-recruitment, an increased frequency of thermally anomalous conditions at the HAI (such as experienced in 2011 has the potential to reduce the long-term stability of the HAI coral populations and species that depend upon them.
Statistical analysis of anomalous transport in resistive interchange turbulence
International Nuclear Information System (INIS)
Sugama, Hideo; Wakatani, Masahiro.
1992-01-01
A new anomalous transport model for resistive interchange turbulence is derived from statistical analysis applying two-scale direct-interaction approximation to resistive magnetohydrodynamic equations with a gravity term. Our model is similar to the K-ε model for eddy viscosity of turbulent shear flows in that anomalous transport coefficients are expressed in terms of by the turbulent kinetic energy K and its dissipation rate ε while K and ε are determined by transport equations. This anomalous transport model can describe some nonlocal effects such as those from boundary conditions which cannot be treated by conventional models based on the transport coefficients represented by locally determined plasma parameters. (author)
Anomalous cross-modulation between microwave beams
Ranfagni, Anedio; Mugnai, Daniela; Petrucci, Andrea; Mignani, Roberto; Cacciari, Ilaria
2018-06-01
An anomalous effect in the near field of crossing microwave beams, which consists of an unexpected transfer of modulation from one beam to the other, has found a plausible interpretation within the framework of a locally broken Lorentz invariance. A theoretical approach of this kind deserves to be reconsidered also in the light of further experimental work, including a counter-check of the phenomenon.
Berg, E.; Lin, F. C.; Qiu, H.; Wang, Y.; Allam, A. A.; Clayton, R. W.; Ben-Zion, Y.
2017-12-01
Rayleigh waves extracted from cross-correlations of ambient seismic noise have proven useful in imaging the shallow subsurface velocity structure. In contrast to phase velocities, which are sensitive to slightly deeper structure, Rayleigh wave ellipticity (H/V ratios) constrains the uppermost crust. We conduct Rayleigh wave ellipticity and phase dispersion measurements in Southern California between 6 and 18 second periods, computed from multi-component ambient noise cross-correlations using 315 stations across the region in 2015. Because of the complimentary sensitivity of phase velocity and H/V, this method enables simple and accurate resolution of near-surface geological features from the surface to 20km depth. We compare the observed H/V ratios and phase velocities to predictions generated from the current regional models (SCEC UCVM), finding strong correspondence where the near-surface structure is well-resolved by the models. This includes high H/V ratios in the LA Basin, Santa Barbara Basin and Salton Trough; and low ratios in the San Gabriel, San Jacinto and southern Sierra Nevada mountains. Disagreements in regions such as the Western Transverse Ranges, Salton Trough, San Jacinto and Elsinore fault zones motivate further work to improve the community models. A new updated 3D isotropic model of the area is derived via a joint inversion of Rayleigh phase dispersions and H/V ratios. Additionally, we examine azimuthal dependence of the H/V ratio to ascertain anisotropy patterns for each station. Clear 180º periodicity is observed for many stations suggesting strong shallow anisotropy across the region including up to 20% along the San Andreas fault, 15% along the San Jacinto Fault and 25% in the LA Basin. To better resolve basin structures, we apply similar techniques to three dense linear geophone arrays in the San Gabriel and San Bernardino basins. The three arrays are composed by 50-125 three-component 5Hz geophones deployed for one month each with 15-25km
Energy Technology Data Exchange (ETDEWEB)
Schmitt, Nikolai [Inria, 2004 Route des Lucioles, BP 93, 06902 Sophia Antipolis Cedex (France); Technische Universitaet Darmstadt, Institut fuer Theorie Elektromagnetischer Felder (TEMF), Schlossgartenstr. 8, 64289 Darmstadt (Germany); Scheid, Claire [Inria, 2004 Route des Lucioles, BP 93, 06902 Sophia Antipolis Cedex (France); University of Nice – Sophia Antipolis, Mathematics laboratory, Parc Valrose, 06108 Nice, Cedex 02 (France); Lanteri, Stéphane, E-mail: Stephane.Lanteri@inria.fr [Inria, 2004 Route des Lucioles, BP 93, 06902 Sophia Antipolis Cedex (France); Moreau, Antoine [Institut Pascal, Université Blaise Pascal, 24, avenue des Landais, 63171 Aubière Cedex (France); Viquerat, Jonathan [Inria, 2004 Route des Lucioles, BP 93, 06902 Sophia Antipolis Cedex (France)
2016-07-01
The interaction of light with metallic nanostructures is increasingly attracting interest because of numerous potential applications. Sub-wavelength metallic structures, when illuminated with a frequency close to the plasma frequency of the metal, present resonances that cause extreme local field enhancements. Exploiting the latter in applications of interest requires a detailed knowledge about the occurring fields which can actually not be obtained analytically. For the latter mentioned reason, numerical tools are thus an absolute necessity. The insight they provide is very often the only way to get a deep enough understanding of the very rich physics at play. For the numerical modeling of light-structure interaction on the nanoscale, the choice of an appropriate material model is a crucial point. Approaches that are adopted in a first instance are based on local (i.e. with no interaction between electrons) dispersive models, e.g. Drude or Drude–Lorentz models. From the mathematical point of view, when a time-domain modeling is considered, these models lead to an additional system of ordinary differential equations coupled to Maxwell's equations. However, recent experiments have shown that the repulsive interaction between electrons inside the metal makes the response of metals intrinsically non-local and that this effect cannot generally be overlooked. Technological achievements have enabled the consideration of metallic structures in a regime where such non-localities have a significant influence on the structures' optical response. This leads to an additional, in general non-linear, system of partial differential equations which is, when coupled to Maxwell's equations, significantly more difficult to treat. Nevertheless, dealing with a linearized non-local dispersion model already opens the route to numerous practical applications of plasmonics. In this work, we present a Discontinuous Galerkin Time-Domain (DGTD) method able to solve the system
Investigation on dispersion in the active optical waveguide resonator
Qiu, Zihan; Gao, Yining; Xie, Wei
2018-03-01
Introducing active gain in the optical waveguide resonator not only compensates the loss, but also can change the dispersion relationship in the ring resonator. It is demonstrated that the group delay time is negative when the resonator is in the undercoupled condition, which also means the resonator exhibits the fast light effect. Theoretical analysis indicates that fast light effect due to anomalous dispersion, would be manipulated by the gain coefficient controlled by the input pump light power and that fast light would enhance scale factor of the optical resonant gyroscope. Resonance optical gyroscope (ROG)'s scale factor for measuring rotation rate is enhanced by anomalous dispersion with superluminal light propagation. The sensitivity of ROG could be enhanced by anomalous dispersion by coupled resonators even considering the effect of anomalous dispersion and propagation gain on broadened linewidth, and this could result in at least two orders of magnitude enhancement in sensitivity.
Anomalous decay and scattering processes of the meson
Kubis, Bastian; Plenter, Judith
2015-06-01
We amend a recent dispersive analysis of the anomalous decay process by the effects of the tensor meson, the lowest-lying resonance that can contribute in the system. While the net effects on the measured decay spectrum are small, they may be more pronounced for the analogous decay. There are nonnegligible consequences for the transition form factor, which is an important quantity for the hadronic light-by-light scattering contribution to the muon's anomalous magnetic moment. We predict total and differential cross sections, as well as a marked forward-backward asymmetry, for the crossed process , which could be measured in Primakoff reactions in the future.
Anomalous photoconductivity of ferrocene
Energy Technology Data Exchange (ETDEWEB)
Chakraborty, A K [Indian Association for the Cultivation of Science, Calcutta (India). Dept. of Spectroscopy; Mallik, B [Indian Association for the Cultivation of Science, Calcutta (India). Dept. of Spectroscopy
1995-08-15
Photoconductivity behaviour of ferrocene, a very useful metallo-organic sandwich compound, has been investigated at different constant temperatures using powdery material in a sandwich type of cell configuration and with the exposure of a polychromatic light source (mercury lamp of 125 W). Measurements with a constant d.c. bias voltage (27 V) across the sample cell and a fixed intensity of the exciting light source have shown a drastic change in the photocurrent versus time profile with the increase in temperature. Anomalous changes have been observed in the plot of the photocurrent versus reciprocal of temperature. Such changes are completely absent in the corresponding dark current behaviour. The photoinduced changes have been observed to be almost reversible in the entire temperature range. In a particular temperature range the reversibility of photocurrent is accompanied by fluctuations in equilibrium current obtained after switching off the light source. The observed anomalous changes in photocurrent have been explained by photoinduced phase transition in ferrocene. The possible origin and implications of this photoinduced phase transition are discussed. (orig.)
Dispersal and metapopulation stability
Directory of Open Access Journals (Sweden)
Shaopeng Wang
2015-10-01
Full Text Available Metapopulation dynamics are jointly regulated by local and spatial factors. These factors may affect the dynamics of local populations and of the entire metapopulation differently. Previous studies have shown that dispersal can stabilize local populations; however, as dispersal also tends to increase spatial synchrony, its net effect on metapopulation stability has been controversial. Here we present a simple metapopulation model to study how dispersal, in interaction with other spatial and local processes, affects the temporal variability of metapopulations in a stochastic environment. Our results show that in homogeneous metapopulations, the local stabilizing and spatial synchronizing effects of dispersal cancel each other out, such that dispersal has no effect on metapopulation variability. This result is robust to moderate heterogeneities in local and spatial parameters. When local and spatial dynamics exhibit high heterogeneities, however, dispersal can either stabilize or destabilize metapopulation dynamics through various mechanisms. Our findings have important theoretical and practical implications. We show that dispersal functions as a form of spatial intraspecific mutualism in metapopulation dynamics and that its effect on metapopulation stability is opposite to that of interspecific competition on local community stability. Our results also suggest that conservation corridors should be designed with appreciation of spatial heterogeneities in population dynamics in order to maximize metapopulation stability.
Anomalous atomic volume of alpha-Pu
DEFF Research Database (Denmark)
Kollar, J.; Vitos, Levente; Skriver, Hans Lomholt
1997-01-01
We have performed full charge-density calculations for the equilibrium atomic volumes of the alpha-phase light actinide metals using the local density approximation (LDA) and the generalized gradient approximation (GGA). The average deviation between the experimental and the GGA atomic radii is 1.......3%. The comparison between the LDA and GGA results show that the anomalously large atomic volume of alpha-Pu relative to alpha-Np can be ascribed to exchange-correlation effects connected with the presence of low coordinated sites in the structure where the f electrons are close to the onset of localization...
Anomalous Dimensions of Conformal Baryons
DEFF Research Database (Denmark)
Pica, Claudio; Sannino, Francesco
2016-01-01
We determine the anomalous dimensions of baryon operators for the three color theory as function of the number of massless flavours within the conformal window to the maximum known order in perturbation theory. We show that the anomalous dimension of the baryon is controllably small, within...
Shtukenberg, Alexander; Kahr, Bart
2007-01-01
Optical anomalies in crystals are puzzles that collectively constituted the greatest unsolved problems in crystallography in the 19th Century. The most common anomaly is a discrepancy between a crystal’s symmetry as determined by its shape or by X-ray analysis, and that determined by monitoring the polarization state of traversing light. These discrepancies were perceived as a great impediment to the development of the sciences of crystals on the basis of Curie’s Symmetry Principle, the grand organizing idea in the physical sciences to emerge in the latter half of the 19th Century. Optically Anomalous Crystals begins with an historical introduction covering the contributions of Brewster, Biot, Mallard, Brauns, Tamman, and many other distinguished crystallographers. From this follows a tutorial in crystal optics. Further chapters discuss the two main mechanisms of optical dissymmetry: 1. the piezo-optic effect, and 2. the kinetic ordering of atoms. The text then tackles complex, inhomogeneous crystals, and...
Ferragut, Erik M.; Laska, Jason A.; Bridges, Robert A.
2016-06-07
A system is described for receiving a stream of events and scoring the events based on anomalousness and maliciousness (or other classification). The system can include a plurality of anomaly detectors that together implement an algorithm to identify low-probability events and detect atypical traffic patterns. The anomaly detector provides for comparability of disparate sources of data (e.g., network flow data and firewall logs.) Additionally, the anomaly detector allows for regulatability, meaning that the algorithm can be user configurable to adjust a number of false alerts. The anomaly detector can be used for a variety of probability density functions, including normal Gaussian distributions, irregular distributions, as well as functions associated with continuous or discrete variables.
Normal-dispersion microresonator Kerr frequency combs
Directory of Open Access Journals (Sweden)
Xue Xiaoxiao
2016-06-01
Full Text Available Optical microresonator-based Kerr frequency comb generation has developed into a hot research area in the past decade. Microresonator combs are promising for portable applications due to their potential for chip-level integration and low power consumption. According to the group velocity dispersion of the microresonator employed, research in this field may be classified into two categories: the anomalous dispersion regime and the normal dispersion regime. In this paper, we discuss the physics of Kerr comb generation in the normal dispersion regime and review recent experimental advances. The potential advantages and future directions of normal dispersion combs are also discussed.
Field enhancement due to anomalous skin effect inside a target
International Nuclear Information System (INIS)
Ma, G.; Tan, W.
1996-01-01
A new method based on Fourier transformation to study the skin effects is presented. Using this method, the field amplitude in plasma is represented in terms of electric conductivity, and the normal and anomalous skin effects are described through one formula by omitting the plasma dispersion or not. The results are in agreement with other publications [e.g., J. P. Matte and K. Aguenaou, Phys. Rev. A 45, 2558 (1992)] for equivalent parameters. But for deeper positions inside a target, which have not been studied by others, it is found that the field amplitude is considerably enhanced due to an anomalous skin effect, even for constant collision frequency. In addition, the skin absorptions and some calculations on an anomalous skin effect for different collision frequencies are also presented. copyright 1996 American Institute of Physics
Terwilliger, Thomas C; Bunkóczi, Gábor; Hung, Li Wei; Zwart, Peter H; Smith, Janet L; Akey, David L; Adams, Paul D
2016-03-01
A key challenge in the SAD phasing method is solving a structure when the anomalous signal-to-noise ratio is low. Here, algorithms and tools for evaluating and optimizing the useful anomalous correlation and the anomalous signal in a SAD experiment are described. A simple theoretical framework [Terwilliger et al. (2016), Acta Cryst. D72, 346-358] is used to develop methods for planning a SAD experiment, scaling SAD data sets and estimating the useful anomalous correlation and anomalous signal in a SAD data set. The phenix.plan_sad_experiment tool uses a database of solved and unsolved SAD data sets and the expected characteristics of a SAD data set to estimate the probability that the anomalous substructure will be found in the SAD experiment and the expected map quality that would be obtained if the substructure were found. The phenix.scale_and_merge tool scales unmerged SAD data from one or more crystals using local scaling and optimizes the anomalous signal by identifying the systematic differences among data sets, and the phenix.anomalous_signal tool estimates the useful anomalous correlation and anomalous signal after collecting SAD data and estimates the probability that the data set can be solved and the likely figure of merit of phasing.
International Nuclear Information System (INIS)
Yagasaki, K; Nakama, T; Takaesu, Y; Hedo, M; Uchima, K; Uwatoko, Y; Burkov, A
2009-01-01
The electrical resistivity ν of the Laves phase Y 1-x R x Co 2 compound system has been measured in magnetic fields up to 10 T and under pressures up to 8 GPa at temperatures from 1.5 to 300 K. The anomalous behavior of residual resistivity has been observed in a region x a , where x a is a critical concentration between inhomogeneously and homogeneously ordered phases, and which has a maximum at x c where T c ∼ 0 with a mean field acting on Co sub-lattice is equal to the itinerant Co metamagnetic critical field B c . In x c a , the magneto-resistivity and pressure resistivity are anomalously large with positive sign. However, in the paramagnetic region for x c , they are anomalously large but with negative sign. The anomalous behavior is attributed to the s-d scattering of conduction electrons due to statistically disordered Co magnetization. Those phenomena can be explained by a new scattering model of [Two magnetization Nordheim model for randomly distributed Co sites] introduced by us.
Nislow, K.H.; Hudy, M.; Letcher, B.H.; Smith, E.P.
2011-01-01
1.Barriers to immigration, all else being equal, should in principle depress local abundance and reduce local species richness. These issues are particularly relevant to stream-dwelling species when improperly designed road crossings act as barriers to migration with potential impacts on the viability of upstream populations. However, because abundance and richness are highly spatially and temporally heterogeneous and the relative importance of immigration on demography is uncertain, population- and community-level effects can be difficult to detect. 2.In this study, we tested the effects of potential barriers to upstream movements on the local abundance and species richness of a diverse assemblage of resident stream fishes in the Monongahela National Forest, West Virginia, U.S.A. Fishes were sampled using simple standard techniques above- and below road crossings that were either likely or unlikely to be barriers to upstream fish movements (based on physical dimensions of the crossing). We predicted that abundance of resident fishes would be lower in the upstream sections of streams with predicted impassable barriers, that the strength of the effect would vary among species and that variable effects on abundance would translate into lower species richness. 3.Supporting these predictions, the statistical model that best accounted for variation in abundance and species richness included a significant interaction between location (upstream or downstream of crossing) and type (passable or impassable crossing). Stream sections located above predicated impassable culverts had fewer than half the number of species and less than half the total fish abundance, while stream sections above and below passable culverts had essentially equivalent richness and abundance. 4.Our results are consistent with the importance of immigration and population connectivity to local abundance and species richness of stream fishes. In turn, these results suggest that when measured at
Nagaosa, Naoto; Sinova, Jairo; Onoda, Shigeki; MacDonald, A. H.; Ong, N. P.
2010-04-01
The anomalous Hall effect (AHE) occurs in solids with broken time-reversal symmetry, typically in a ferromagnetic phase, as a consequence of spin-orbit coupling. Experimental and theoretical studies of the AHE are reviewed, focusing on recent developments that have provided a more complete framework for understanding this subtle phenomenon and have, in many instances, replaced controversy by clarity. Synergy between experimental and theoretical works, both playing a crucial role, has been at the heart of these advances. On the theoretical front, the adoption of the Berry-phase concepts has established a link between the AHE and the topological nature of the Hall currents. On the experimental front, new experimental studies of the AHE in transition metals, transition-metal oxides, spinels, pyrochlores, and metallic dilute magnetic semiconductors have established systematic trends. These two developments, in concert with first-principles electronic structure calculations, strongly favor the dominance of an intrinsic Berry-phase-related AHE mechanism in metallic ferromagnets with moderate conductivity. The intrinsic AHE can be expressed in terms of the Berry-phase curvatures and it is therefore an intrinsic quantum-mechanical property of a perfect crystal. An extrinsic mechanism, skew scattering from disorder, tends to dominate the AHE in highly conductive ferromagnets. The full modern semiclassical treatment of the AHE is reviewed which incorporates an anomalous contribution to wave-packet group velocity due to momentum-space Berry curvatures and correctly combines the roles of intrinsic and extrinsic (skew-scattering and side-jump) scattering-related mechanisms. In addition, more rigorous quantum-mechanical treatments based on the Kubo and Keldysh formalisms are reviewed, taking into account multiband effects, and demonstrate the equivalence of all three linear response theories in the metallic regime. Building on results from recent experiment and theory, a
International Nuclear Information System (INIS)
Jiang, Tianying; Zukoski, Charles F.
2014-01-01
For decades, attempts have been made to understand the formation of colloidal glasses and gels by linking suspension mechanics to particle properties where details of size, shape, and spatial dependencies of pair potentials present a bewildering array of variables that can be manipulated to achieve observed properties. Despite the range of variables that control suspension properties, one consistent observation is the remarkably similarity of flow properties observed as particle properties are varied. Understanding the underlying origins of the commonality in those behaviors (e.g., shear-thinning with increasing stress, diverging zero shear rate viscosity with increasing volume fraction, development of a dynamic yield stress plateau with increases in volume faction or strength of attraction, development of two characteristic relaxation times probed in linear viscoelasticity, the creation of a rubbery plateau modulus at high strain frequencies, and shear-thickening) remains a challenge. Recently, naïve mode coupling and dynamic localization theories have been developed to capture collective behavior giving rise to formation of colloidal glasses and gels. This approach characterizes suspension mechanics of strongly interacting particles in terms of sluggish long-range particle diffusion modulated by varying particle interactions and volume fraction. These theories capture the scaling of the modulus with the volume fraction and strength of interparticle attraction, the frequency dependence of the moduli at the onset of the gel/glass transition, together with the divergence of the zero shear rate viscosity and cessation of diffusivity for hard sphere systems as close packing is approached. In this study, we explore the generality of the predictions of dynamic localization theory for systems of particles composed of bimodal particle size distributions experiencing weak interactions. We find that the mechanical properties of these suspensions are well captured within
Energy Technology Data Exchange (ETDEWEB)
Jiang, Tianying; Zukoski, Charles F., E-mail: czukoski@illinois.edu [Department of Chemical and Biomolecular Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois 61801 (United States)
2014-09-01
For decades, attempts have been made to understand the formation of colloidal glasses and gels by linking suspension mechanics to particle properties where details of size, shape, and spatial dependencies of pair potentials present a bewildering array of variables that can be manipulated to achieve observed properties. Despite the range of variables that control suspension properties, one consistent observation is the remarkably similarity of flow properties observed as particle properties are varied. Understanding the underlying origins of the commonality in those behaviors (e.g., shear-thinning with increasing stress, diverging zero shear rate viscosity with increasing volume fraction, development of a dynamic yield stress plateau with increases in volume faction or strength of attraction, development of two characteristic relaxation times probed in linear viscoelasticity, the creation of a rubbery plateau modulus at high strain frequencies, and shear-thickening) remains a challenge. Recently, naïve mode coupling and dynamic localization theories have been developed to capture collective behavior giving rise to formation of colloidal glasses and gels. This approach characterizes suspension mechanics of strongly interacting particles in terms of sluggish long-range particle diffusion modulated by varying particle interactions and volume fraction. These theories capture the scaling of the modulus with the volume fraction and strength of interparticle attraction, the frequency dependence of the moduli at the onset of the gel/glass transition, together with the divergence of the zero shear rate viscosity and cessation of diffusivity for hard sphere systems as close packing is approached. In this study, we explore the generality of the predictions of dynamic localization theory for systems of particles composed of bimodal particle size distributions experiencing weak interactions. We find that the mechanical properties of these suspensions are well captured within
Anomalous momentum transport from drift waves
International Nuclear Information System (INIS)
Dominguez, R.R.; Staebler, G.M.
1993-01-01
A sheared slab magnetic field model B = B 0 [z + (x/L s )y], with inhomogeneous flows in the y and z directions, is used to perform a fully-kinetic stability analysis of the ion temperature gradient (ITG) and dissipative trapped electron (DTE) modes. The concomitant quasilinear stress components that couple to the local perpendicular (y-component) and parallel (z-component) momentum transport are also calculated and the anomalous perpendicular and parallel viscous stresses obtained. A breakdown of the ITG-induced perpendicular viscous stress is generally observed at moderate values of the sheared perpendicular flow. The ITG-induced parallel viscous stress is generally larger and strongly dependent on the sheared flows. The DTE-induced perpendicular viscous stress may sometimes be negative, tending to cancel the ITG contributions while the DTE-induced parallel viscous stress is generally small. The effect of the perpendicular stress component in the momentum balance equations is generally small while the parallel stress component can dominate the usual neoclassical viscous stress terms. The dominant contribution to parallel viscous stress by the ITG mode suggests that bulk plasma toroidal momentum confinement, like energy confinement, is governed by an anomalous ion loss mechanism. Furthermore, the large anomalous effect suggests that the neoclassical explanation of poloidal flows in tokamaks may be incorrect. The present results are in general agreement with existing experimental observations on momentum transport in tokamaks
Tan, C. L.
2010-02-11
The authors report on the nanowires-like and nanodots-like lasing behaviors in addition to multiple-wavelength interband transitions from InAs/InAlGaAs quantum dash (Qdash) lasers in the range of ~1550 nm. The presence of lasing actions simultaneously from two different dash ensembles, after postgrowth intermixing for crystalline quality improvement, indicate the absence of optical phonon emission due to the small variation in quantized interband transition energies. This effect is reproducible and shows different lasing characteristics from its quantum dot and quantum wire laser counterparts. Furthermore, the small energy spacing of only 25 nm (at center lasing wavelength of ~1550 nm) and the subsequent quenching of higher energy transition states at higher bias level in Qdash lasers suggest the absence of excited-state transition in highly inhomogeneous self-assembled Qdash structures. However, the appearance of a second lasing line in a certain range of high injection level, which is due to the presence of different sizes of dash assembles, corresponds to the transition from smaller size of Qdash ensembles in different planar active medium. This unique transition mechanism will affect the carrier dynamics, relaxation process in particular and further indicates localized finite carrier lifetime in all sizes of Qdash ensembles. These phenomena will lead to important consequences for the ground-state lasing efficiency and frequency modulation response of Qdash devices. In addition, these imply that proper manipulation of the Qdash ensembles will potentially result in localized nanolasers from individual ensemble and thus contributing towards enormously large envelope lasing coverage from semiconductor devices.
Anomalous spreading behaviour of polyethyleneglycoldistearate ...
Indian Academy of Sciences (India)
Unknown
Anomalous behaviour; polythyleneglycoldistearate; air/water interface; ... distinguished these monolayer states in terms of molecular ordering, including the .... It has been found that the compressibilities of the materials in the condensed phase.
Renewal-anomalous-heterogeneous files
International Nuclear Information System (INIS)
Flomenbom, Ophir
2010-01-01
Renewal-anomalous-heterogeneous files are solved. A simple file is made of Brownian hard spheres that diffuse stochastically in an effective 1D channel. Generally, Brownian files are heterogeneous: the spheres' diffusion coefficients are distributed and the initial spheres' density is non-uniform. In renewal-anomalous files, the distribution of waiting times for individual jumps is not exponential as in Brownian files, yet obeys: ψ α (t)∼t -1-α , 0 2 >, obeys, 2 >∼ 2 > nrml α , where 2 > nrml is the MSD in the corresponding Brownian file. This scaling is an outcome of an exact relation (derived here) connecting probability density functions of Brownian files and renewal-anomalous files. It is also shown that non-renewal-anomalous files are slower than the corresponding renewal ones.
The origin of anomalous transport in porous media - is it possible to make a priori predictions?
Bijeljic, Branko; Blunt, Martin
2013-04-01
Despite the range of significant applications of flow and solute transport in porous rock, including contaminant migration in subsurface hydrology, geological storage of carbon-dioxide and tracer studies and miscible displacement in oil recovery, even the qualitative behavior in the subsurface is uncertain. The non-Fickian nature of dispersive processes in heterogeneous porous media has been demonstrated experimentally from pore to field scales. However, the exact relationship between structure, velocity field and transport has not been fully understood. Advances in X ray imaging techniques made it possible to accurately describe structure of the pore space, helping predict flow and anomalous transport behaviour using direct simulation. This is demonstrated by simulating solute transport through 3D images of rock samples, with resolutions of a few microns, representing geological media of increasing pore-scale complexity: a sandpack, a sandstone, and a carbonate. A novel methodology is developed that predicts solute transport at the pore scale by using probability density functions of displacement (propagators) and probability density function of transit time between the image voxels, and relates it to probability density function of normalized local velocity. A key advantage is that full information on velocity and solute concentration is retained in the models. The methodology includes solving for Stokes flow by Open Foam, solving for advective transport by the novel streamline simulation method, and superimposing diffusive transport diffusion by the random walk method. It is shown how computed propagators for beadpack, sandstone and carbonate depend on the spread in the velocity distribution. A narrow velocity distribution in the beadpack leads to the least anomalous behaviour where the propagators rapidly become Gaussian; the wider velocity distribution in the sandstone gives rise to a small immobile concentration peak, and a large secondary mobile peak moving
Kazeykina, Anna; Muñoz, Claudio
2018-04-01
We continue our study on the Cauchy problem for the two-dimensional Novikov-Veselov (NV) equation, integrable via the inverse scattering transform for the two dimensional Schrödinger operator at a fixed energy parameter. This work is concerned with the more involved case of a positive energy parameter. For the solution of the linearized equation we derive smoothing and Strichartz estimates by combining new estimates for two different frequency regimes, extending our previous results for the negative energy case [18]. The low frequency regime, which our previous result was not able to treat, is studied in detail. At non-low frequencies we also derive improved smoothing estimates with gain of almost one derivative. Then we combine the linear estimates with a Fourier decomposition method and Xs,b spaces to obtain local well-posedness of NV at positive energy in Hs, s > 1/2. Our result implies, in particular, that at least for s > 1/2, NV does not change its behavior from semilinear to quasilinear as energy changes sign, in contrast to the closely related Kadomtsev-Petviashvili equations. As a complement to our LWP results, we also provide some new explicit solutions of NV at zero energy, generalizations of the lumps solutions, which exhibit new and nonstandard long time behavior. In particular, these solutions blow up in infinite time in L2.
International Nuclear Information System (INIS)
Waxman, A.M.
1980-01-01
This paper concerns the geometry and physical properties of waves which arise from a shear-flow (i.e. inflection point) instability of the galactic boundary layer circulation. This circulation was shown to exist in the meridional plane of a model galaxy containing a gaseous disk embedded in a rotating gaseous halo. Previously derived equations describe the local effects of Boussinesq perturbations, in the form of spiral waves with aribitrary pitch angle, on the model disk-halo system. The equations are solved asymptotically for large values of the local Reynolds number. In passing to the limit of inviscid waves, it is possible to derive a locally valid dispersion relation. A perturbation technique is developed whereby the inviscid wave eigenvalues can be corrected for the effects of small but finite viscosity. In this way the roles of the buoyancy force, Coriolis acceleration, viscous stresses, and their interactions can be studied. It is found that, locally, the most unstable inviscid waves are leading and open with large azimuthal wavenumbers. However, these waves display little or no coherence over the face of the disk and so would not emerge as modes in a global analysis.The geometry of the dominant inviscid waves is found to be leading, tightly wound spirals. Viscous corrections shift the dominant wave form to trailing, tightly wound spirals with small azimuthal wavenumbers. These waves grow on a time scale of about 10 7 years. It is suggested that these waves can initiate spiral structure in galaxies during disk formation and that a subsequent transition to a self-gravitating acoustical mode with the same spiral geometry may occur. This transition becomes possible once the contrast in gas densities between the disk and surrounding halo becomes sufficiently large
Anomalous diffusion in chaotic scattering
International Nuclear Information System (INIS)
Srokowski, T.; Ploszajczak, M.
1994-01-01
The anomalous diffusion is found for peripheral collision of atomic nuclei described in the framework of the molecular dynamics. Similarly as for chaotic billiards, the long free paths are the source of the long-time correlations and the anomalous diffusion. Consequences of this finding for the energy dissipation in deep-inelastic collisions and the dynamics of fission in hot nuclei are discussed (authors). 30 refs., 2 figs
Anomalous magnetoresistance in amorphous metals
International Nuclear Information System (INIS)
Kuz'menko, V.M.; Vladychkin, A.N.; Mel'nikov, V.I.; Sudovtsev, A.I.
1984-01-01
The magnetoresistance of amorphous Bi, Ca, V and Yb films is investigated in fields up to 4 T at low temperatures. For all metals the magnetoresistance is positive, sharply decreases with growth of temperature and depends anomalously on the magnetic field strength. For amorphous superconductors the results agree satisfactorily with the theory of anomalous magnetoresistance in which allowance is made for scattering of electrons by the superconducting fluctuations
Fractional Diffusion Equations and Anomalous Diffusion
Evangelista, Luiz Roberto; Kaminski Lenzi, Ervin
2018-01-01
Preface; 1. Mathematical preliminaries; 2. A survey of the fractional calculus; 3. From normal to anomalous diffusion; 4. Fractional diffusion equations: elementary applications; 5. Fractional diffusion equations: surface effects; 6. Fractional nonlinear diffusion equation; 7. Anomalous diffusion: anisotropic case; 8. Fractional Schrödinger equations; 9. Anomalous diffusion and impedance spectroscopy; 10. The Poisson–Nernst–Planck anomalous (PNPA) models; References; Index.
Hindle, Tony; Hindle, Giles; Spollen, Martin
2009-02-01
The aim of this research has been to make a contribution to deliberations concerning the relative costs of provision of domiciliary services for the elderly in local authorities in England and the implications for funding. The main services considered have been day-centre services and home-care services, and the particular cost areas investigated have been travel-related costs as associated with distances travelled by day-centre vehicles and care workers and with worker travelling hours. These costs are influenced by the population settlement and dispersion characteristics of the areas served and funding mechanisms are needed (and are in place) to compensate service providers. However, current mechanisms have been widely criticized and the research reported here reaches conclusions about whether such criticisms are justified and how improvements might be brought about. The methods used have involved detailed operational modelling of the selected services in a sample of local authority areas and the generalization of the findings to England as a whole.
International Nuclear Information System (INIS)
Aydemir, A.Y.
1990-01-01
We derive the dispersion relations for both small and large-Δ' modes (m ≥ 2, and m = 1 modes, respectively) driven by anomalous electron viscosity. Under the assumption that the anomalous kinematic electron viscosity is comparable to the anomalous electron thermal diffusivity, we find that the viscous mode typically has a higher growth rate than the corresponding resistive mode. We compare computational results in cylindrical and toroidal geometries with theory and present some nonlinear results for viscous m = 1 modes in both circular and D-shaped boundaries and discuss their possible rile in fast sawtooth crashes. 30 ref., 5 figs., 1 tab
Kangsabanik, Jiban; Chouhan, Rajiv K.; Johnson, D. D.; Alam, Aftab
2017-09-01
Gold iron (Au-Fe) alloys are of immense interest due to their biocompatibility, anomalous Hall conductivity, and applications in various medical treatments. However, irrespective of the method of preparation, they often exhibit a high level of disorder with properties sensitive to the thermal or magnetic annealing temperatures. We calculate the lattice dynamical properties of Au1 -xFex alloys using density functional theory methods where, being multisite properties, reliable interatomic force constant (IFC) calculations in disordered alloys remain a challenge. We follow a twofold approach: (1) an accurate IFC calculation in an environment with nominally zero chemical pair correlations to mimic the homogeneously disordered alloy and (2) a configurational averaging for the desired phonon properties (e.g., dispersion, density of states, and entropy). We find an anomalous change in the IFC's and phonon dispersion (split bands) near x =0.19 , which is attributed to the local stiffening of the Au-Au bonds when Au is in the vicinity of Fe. Other results based on mechanical and thermophysical properties reflect a similar anomaly: Phonon entropy, e.g., becomes negative below x =0.19 , suggesting a tendency for chemical unmixing, reflecting the onset of a miscibility gap in the phase diagram. Our results match fairly well with reported data wherever available.
Zhang, Hao; Li, Wenxiu; Han, Peng; Chang, Xiaoyang; Liu, Jiaming; Lin, Jian; Xue, Xia; Zhu, Fang; Yang, Yang; Liu, Xiaojing; Zhang, Xiaofu; Huang, Anping; Xiao, Zhisong; Fang, Jiancheng
2018-01-01
Anomalous dispersion enhancement physical mechanism for Sagnac effect is described by special relativity derivation, and three kinds of definitions of minimum detectable angular rate of resonance optical gyroscope (ROG) are compared and the relations among them are investigated. The effect of linewidth broadening induced by anomalous dispersion on the sensitivity of ROG is discussed in this paper. Material dispersion-broadened resonance linewidth deteriorates the performance of a passive ROG and dispersion enhancement effect, while the sensitivity of a structural dispersion ROG is enhanced by two orders of magnitude even considering the dispersion-broadened resonance linewidth.
Anomalous tensoelectric effects in gallium arsenide tunnel diodes
Energy Technology Data Exchange (ETDEWEB)
Alekseeva, Z.M.; Vyatkin, A.P.; Krivorotov, N.P.; Shchegol' , A.A.
1988-02-01
Anomalous tensoelectric phenomena induced in a tunnel p-n junction by a concentrated load and by hydrostatic compression were studied. The anomalous tensoelectric effects are caused by the action of concentrators of mechanical stresses in the vicinity of the p-n junction, giving rise to local microplastic strain. Under the conditions of hydrostatic compression prolate inclusions approx.100-200 A long play the role of concentrators. Analysis of irreversible changes in the current-voltage characteristics of tunnel p-n junctions made it possible to separate the energy levels of the defects produced with plastic strain of gallium arsenide.
International Nuclear Information System (INIS)
Fayolle, D.
2002-01-01
In its second phase, LEP has allowed to study four fermion processes never observed before. Results are presented on the charged triple gauge boson couplings (TGC) from the W-pair, Single W and Single γ production. The anomalous quartic gauge couplings (QGC) are constrained using production of WWγ, νν-barγγ and Z γγ final states. Finally, limits on the neutral anomalous gauge couplings (NGC) using the Z γ and ZZ production processes are also reported. All results are consistent with the Standard Model expectations. (authors)
Computer simulations of anomalous transport
International Nuclear Information System (INIS)
Lee, W.W.; Okuda, H.
1980-07-01
Numerical plasma simulations have been carried out to study: (1) the turbulent spectrum and anomalous plasma transport associated with a steady state electrostatic drift turbulence; and (2) the anomalous energy transport of electrons due to shear-Alfven waves in a finite-β plasma. For the simulation of the steady state drift turbulence, it is observed that, in the absence of magnetic shear, the turbulence is quenched to a low level when the rotational transform is a rational number, while the turbulent level remains high for an irrational rotational transform
Directory of Open Access Journals (Sweden)
Abílio Amiguinho
2005-01-01
Full Text Available The process of socio-educational territorialisation in rural contexts is the topic of this text. The theme corresponds to a challenge to address it having as main axis of discussion either the problem of social exclusion or that of local development. The reasons to locate the discussion in this last field of analysis are discussed in the first part of the text. Theoretical and political reasons are there articulated because the question is about projects whose intentions and practices call for the political both in the theoretical debate and in the choices that anticipate intervention. From research conducted for several years, I use contributions that aim at discuss and enlighten how school can be a potential locus of local development. Its identification and recognition as local institution (either because of those that work and live in it or because of those that act in the surrounding context are crucial steps to progressively constitute school as a partner for development. The promotion of the local values and roots, the reconstruction of socio-personal and local identities, the production of sociabilities and the equation and solution of shared problems were the dimensions of a socio-educative intervention, markedly globalising. This scenario, as it is argued, was also, intentionally, one of transformation and of deliberate change of school and of the administration of the educative territoires.
Absence of U(1) anomalous superamplitudes in N≥5 supergravities
Energy Technology Data Exchange (ETDEWEB)
Freedman, Daniel Z. [Stanford Institute for Theoretical Physics and Department of Physics, Stanford University,Stanford, CA 94305 (United States); Center for Theoretical Physics and Department of Mathematics,Massachusetts Institute of Technology,Cambridge, MA 02139 (United States); Kallosh, Renata; Murli, Divyanshu [Stanford Institute for Theoretical Physics and Department of Physics, Stanford University,Stanford, CA 94305 (United States); Proeyen, Antoine Van [KU Leuven, Institute for Theoretical Physics,Celestijnenlaan 200D, B-3001, Leuven (Belgium); Yamada, Yusuke [Stanford Institute for Theoretical Physics and Department of Physics, Stanford University,Stanford, CA 94305 (United States)
2017-05-12
We list all potential candidates for U(1) anomalous non-local 1-loop 4-point amplitudes and higher loop UV divergences in N≥5 supergravities. The relevant chiral superinvariants are constructed from linearized chiral superfields and define the corresponding superamplitudes. The anomalous amplitudes, of the kind present in N=4, are shown to be absent in N≥5. In N=6 supergravity the result is deduced from the double-copy (N=4){sub YM}×(N=2){sub YM} model, whereas in N=5,8 the result on absence of anomalous amplitudes is derived in supergravities as well as in the (N=4){sub YM}×(N−4){sub YM} double-copy models.
Observations of Anomalous Refraction with Co-housed Telescopes
Taylor, Malinda S.; McGraw, J. T.; Zimmer, P. C.
2013-01-01
Anomalous refraction is described as a low frequency, large angular scale motion of the entire image plane with respect to the celestial coordinate system as observed and defined by previous astrometric catalogs. These motions of typically several tenths of an arcsecond with timescales on the order of ten minutes are ubiquitous to drift-scan ground-based astrometric measurements regardless of location or telescopes used and have been attributed to meter scale slowly evolving coherent dynamical structures in the boundary-layer below 60 meters. The localized nature of the effect and general inconsistency of the motions seen by even closely spaced telescopes in individual domes has led to the hypothesis that the dome or other type of telescope housing may be responsible. This hypothesis is tested by observing anomalous refraction using two telescopes housed in a single roll-off roof observatory building with the expected outcome that the two telescopes will see correlated anomalous refraction induced motions.
Observed anomalous upwelling in the Lakshadweep Sea during the summer monsoon season of 2005
Digital Repository Service at National Institute of Oceanography (India)
Gopalakrishna, V.V.; Rao, R.R.; Nisha, K.; GirishKumar, M.S.; Pankajakshan, T.; Ravichandran, M.; Johnson, Z.; Girish, K.; Aneeshkumar, N.; Srinath, M.; Rajesh, S.; Rajan, C.K.
of local and remote forcings are examined to explain the observed anomalous upwelling during SMS of 2005. The equatorward alongshore wind stress (WS) along the KK XBT transect persisted in a transient manner beyond September only during SMS of 2005...
Fractional charge and anomalous commutators
International Nuclear Information System (INIS)
Frishman, Y.; Gepner, D.
1983-06-01
Non-integer charges on topological objects in the presence of fermions are further investigated. The connection with anomalous commutators is discussed. The reason for the identical results in two-dimensional solutions and four-dimensional monopoles is pointed out. (author)
Anomalous decay and scattering processes of the η meson
International Nuclear Information System (INIS)
Kubis, Bastian; Plenter, Judith
2015-01-01
We amend a recent dispersive analysis of the anomalous η decay process η → π + π - γ by the effects of the a2 tensor meson, the lowest-lying resonance that can contribute in the πη system. While the net effects on the measured decay spectrum are small, they may be more pronounced for the analogous η' decay. There are nonnegligible consequences for the η transition form factor, which is an important quantity for the hadronic light-by-light scattering contribution to the muon's anomalous magnetic moment. We predict total and differential cross sections, as well as a marked forward.backward asymmetry, for the crossed process γπ - → π - η, which could be measured in Primakoff reactions in the future. (orig.)
Anomalous decay and scattering processes of the η meson
Energy Technology Data Exchange (ETDEWEB)
Kubis, Bastian, E-mail: kubis@hiskp.uni-bonn.de [Helmholtz-Institut für Strahlen- und Kernphysik, Universität Bonn, 53115, Bonn (Germany); Bethe Center for Theoretical Physics, Universität Bonn, 53115, Bonn (Germany); Plenter, Judith [Helmholtz-Institut für Strahlen- und Kernphysik, Universität Bonn, 53115, Bonn (Germany)
2015-06-25
We amend a recent dispersive analysis of the anomalous η decay process η→π{sup +}π{sup -}γ by the effects of the a{sub 2} tensor meson, the lowest-lying resonance that can contribute in the πη system. While the net effects on the measured decay spectrum are small, they may be more pronounced for the analogous η{sup ′} decay. There are nonnegligible consequences for the η transition form factor, which is an important quantity for the hadronic light-by-light scattering contribution to the muon’s anomalous magnetic moment. We predict total and differential cross sections, as well as a marked forward–backward asymmetry, for the crossed process γπ{sup -}→π{sup -}η, which could be measured in Primakoff reactions in the future.
Anomalous decay and scattering processes of the η meson
Energy Technology Data Exchange (ETDEWEB)
Kubis, Bastian [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik, Bonn (Germany); Universitaet Bonn, Bethe Center for Theoretical Physics, Bonn (Germany); Plenter, Judith [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik, Bonn (Germany)
2015-06-15
We amend a recent dispersive analysis of the anomalous η decay process η → π{sup +}π{sup -}γ by the effects of the a2 tensor meson, the lowest-lying resonance that can contribute in the πη system. While the net effects on the measured decay spectrum are small, they may be more pronounced for the analogous η' decay. There are nonnegligible consequences for the η transition form factor, which is an important quantity for the hadronic light-by-light scattering contribution to the muon's anomalous magnetic moment. We predict total and differential cross sections, as well as a marked forward.backward asymmetry, for the crossed process γπ{sup -} → π{sup -}η, which could be measured in Primakoff reactions in the future. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Bulatov, A.I.; Chernov, V.S.; Prokopov, L.I.; Proselkov, Yu.M.; Tikhonov, Yu.P.
1980-01-15
A hydrodynamic disperser is suggested which contains a housing, slit nozzles installed on a circular base arranged opposite from each other, resonators secured opposite the nozzle and outlet sleeve. In order to improve the effectiveness of dispersion by throttling the flow, each resonator is made in the form of a crimped plate with crimpings that decrease in height in a direction towards the nozzle.
Anomalous Quantum Correlations of Squeezed Light
Kühn, B.; Vogel, W.; Mraz, M.; Köhnke, S.; Hage, B.
2017-04-01
Three different noise moments of field strength, intensity, and their correlations are simultaneously measured. For this purpose a homodyne cross-correlation measurement [1] is implemented by superimposing the signal field and a weak local oscillator on an unbalanced beam splitter. The relevant information is obtained via the intensity noise correlation of the output modes. Detection details like quantum efficiencies or uncorrelated dark noise are meaningless for our technique. Yet unknown insight in the quantumness of a squeezed signal field is retrieved from the anomalous moment, correlating field strength with intensity noise. A classical inequality including this moment is violated for almost all signal phases. Precognition on quantum theory is superfluous, as our analysis is solely based on classical physics.
Schwinger Model Mass Anomalous Dimension
Keegan, Liam
2016-06-20
The mass anomalous dimension for several gauge theories with an infrared fixed point has recently been determined using the mode number of the Dirac operator. In order to better understand the sources of systematic error in this method, we apply it to a simpler model, the massive Schwinger model with two flavours of fermions, where analytical results are available for comparison with the lattice data.
Anomalous diffusion in geophysical and laboratory turbulence
Directory of Open Access Journals (Sweden)
A. Tsinober
1994-01-01
Full Text Available We present an overview and some new results on anomalous diffusion of passive scalar in turbulent flows (including those used by Richardson in his famous paper in 1926. The obtained results are based on the analysis of the properties of invariant quantities (energy, enstrophy, dissipation, enstrophy generation, helicity density, etc. - i.e. independent of the choice of the system of reference as the most appropriate to describe physical processes - in three different turbulent laboratory flows (grid-flow, jet and boundary layer, see Tsinober et al. (1992 and Kit et al. (1993. The emphasis is made on the relations between the asymptotic properties of the intermittency exponents of higher order moments of different turbulent fields (energy, dissipation, helicity, spontaneous breaking of isotropy and reflexional symmetry and the variability of turbulent diffusion in the atmospheric boundary layer, in the troposphere and in the stratosphere. It is argued that local spontaneous breaking of isotropy of turbulent flow results in anomalous scaling laws for turbulent diffusion (as compared to the scaling law of Richardson which are observed, as a rule, in different atmospheric layers from the atmospheric boundary layer (ABL to the stratosphere. Breaking of rotational symmetry is important in the ABL, whereas reflexional symmetry breaking is dominating in the troposphere locally and in the stratosphere globally. The results are of speculative nature and further analysis is necessary to validate or disprove the claims made, since the correspondence with the experimental results may occur for the wrong reasons as happens from time to time in the field of turbulence.
Dispersive waves induced by self-defocusing temporal solitons in a beta-barium-borate crystal
DEFF Research Database (Denmark)
Zhou, Binbin; Bache, Morten
2015-01-01
We experimentally observe dispersive waves in the anomalous dispersion regime of a beta-barium-borate (BBO) crystal, induced by a self-defocusing few-cycle temporal soliton. Together the soliton and dispersive waves form an energetic octave-spanning supercontinuum. The soliton was excited...
Anomalous interactions in confined charge-stabilized colloid
International Nuclear Information System (INIS)
Grier, D G; Han, Y
2004-01-01
Charge-stabilized colloidal spheres dispersed in weak 1:1 electrolytes are supposed to repel each other. Consequently, experimental evidence for anomalous long-ranged like-charged attractions induced by geometric confinement inspired a burst of activity. This has largely subsided because of nagging doubts regarding the experiments' reliability and interpretation. We describe a new class of thermodynamically self-consistent colloidal interaction measurements that confirm the appearance of pairwise attractions among colloidal spheres confined by one or two bounding walls. In addition to supporting previous claims for this as-yet unexplained effect, these measurements also cast new light on its mechanism
Singh, Anar; Moriyoshi, Chikako; Kuroiwa, Yoshihiro; Pandey, Dhananjai
2018-04-01
We report here the relaxor ferroelectric (RFE) behaviour in a multiferroic solid solution system, (Bi1-xBax)(Fe1-xTix)O3, at a critical disorder level of xC ˜ 0.35 in BiFeO3 and 0.65 (i.e., 1-xC = 0.35) in BaTiO3 similar to the 1:2 ratio of Mg2+ and Nb5+ in the canonical RFE Pb(Mg1/3Nb2/3)O3. This Pb-free system, like canonical Pb-based RFEs, does not exhibit macroscopic symmetry breaking and shows only the signatures of ergodicity breaking at Vogel-Fulcher freezing temperature (TVF). The atomic displacement parameters (ADPs) of Fe3+/Ti4+ and O2-, obtained using high wave vector (Q) and high-resolution synchrotron x-ray diffraction data as a function of temperature, show anomalous diffuse peaks in the Curie range. It is shown that the diffuse peak in ADPs is due to softening of the vibrational frequencies of the B-O chain (B = Fe3+/Ti4+ and O = O2-) below the Burns temperature (TB) followed by hardening below the characteristic temperature (T'm), which corresponds to a peak in the dielectric permittivity (ɛ').
Energy Technology Data Exchange (ETDEWEB)
Hegde, Raghurama P.; Fedorov, Alexander A.; Sauder, J. Michael; Burley, Stephen K.; Almo, Steven C.; Ramagopal, Udupi A.
2017-03-22
Single-wavelength anomalous dispersion (SAD) utilizing anomalous signal from native S atoms, or other atoms with
Taylor dispersion on a fractal
International Nuclear Information System (INIS)
Mazo, R.M.
1998-01-01
Taylor dispersion is the greatly enhanced diffusion in the direction of a fluid flow caused by ordinary diffusion in directions orthogonal to the flow. It is essential that the system be bounded in space in the directions orthogonal to the flow. We investigate the situation where the medium through which the flow occurs has fractal properties so that diffusion in the orthogonal directions is anomalous and non-Fickian. The effective diffusion in the flow direction remains normal; its width grows proportionally with the time. However, the proportionality constant depends on the fractal dimension of the medium as well as its walk dimension. (author)
Buhmann, Stefan Yoshi
2012-01-01
In this book, a modern unified theory of dispersion forces on atoms and bodies is presented which covers a broad range of advanced aspects and scenarios. Macroscopic quantum electrodynamics is shown to provide a powerful framework for dispersion forces which allows for discussing general properties like their non-additivity and the relation between microscopic and macroscopic interactions. It is demonstrated how the general results can be used to obtain dispersion forces on atoms in the presence of bodies of various shapes and materials. Starting with a brief recapitulation of volume I, this volume II deals especially with bodies of irregular shapes, universal scaling laws, dynamical forces on excited atoms, enhanced forces in cavity quantum electrodynamics, non-equilibrium forces in thermal environments and quantum friction. The book gives both the specialist and those new to the field a thorough overview over recent results in the field. It provides a toolbox for studying dispersion forces in various contex...
Revisiting the Anomalous rf Field Penetration into a Warm Plasma
International Nuclear Information System (INIS)
Kaganovich, Igor D.; Polomarov, Oleg V.; Theodosiou, Constantine E.
2005-01-01
Radio-frequency [rf] waves do not penetrate into a plasma and are damped within it. The electric field of the wave and plasma current are concentrated near the plasma boundary in a skin layer. Electrons can transport the plasma current away from the skin layer due to their thermal motion. As a result, the width of the skin layer increases when electron temperature effects are taken into account. This phenomenon is called anomalous skin effect. The anomalous penetration of the rf electric field occurs not only for transversely propagating to the plasma boundary wave (inductively coupled plasmas) but also for the wave propagating along the plasma boundary (capacitively coupled plasmas). Such anomalous penetration of the rf field modifies the structure of the capacitive sheath. Recent advances in the nonlinear, non-local theory of the capacitive sheath are reported. It is shown that separating the electric field profile into exponential and non-exponential parts yields an efficient qualitative and quantitative description of the anomalous skin effect in both inductively and capacitively coupled plasma
Anomalous Nernst Effects of [CoSiB/Pt] Multilayer Films
Kelekci, O.; Lee, H. N.; Kim, T. W.; Noh, H.
2013-01-01
We report a measurement for the anomalous Nernst effects induced by a temperature gradient in [CoSiB/Pt] multilayer films with perpendicular magnetic anisotropy. The Nernst voltage shows a characteristic hysteresis which reflects the magnetization of the film as in the case of the anomalous Hall effects. With a local heating geometry, we also measure the dependence of the anomalous Nernst voltage on the distance d from the heating element. It is roughly proportional to 1/d^1.3, which can be c...
UCN anomalous losses and the UCN capture cross section on material defects
International Nuclear Information System (INIS)
Serebrov, A.; Romanenko, N.; Zherebtsov, O.; Lasakov, M.; Vasiliev, A.; Fomin, A.; Geltenbort, P.; Krasnoshekova, I.; Kharitonov, A.; Varlamov, V.
2005-01-01
Experimental data shows anomalously large ultra cold neutrons (UCN) reflection losses and that the process of UCN reflection is not completely coherent. UCN anomalous losses under reflection cannot be explained in the context of neutron optics calculations. UCN losses by means of incoherent scattering on material defects are considered and cross-section values calculated. The UCN capture cross section on material defects is enhanced by a factor of 10 4 due to localization of UCN around defects. This phenomenon can explain anomalous losses of UCN
Metapopulation extinction risk: dispersal's duplicity.
Higgins, Kevin
2009-09-01
Metapopulation extinction risk is the probability that all local populations are simultaneously extinct during a fixed time frame. Dispersal may reduce a metapopulation's extinction risk by raising its average per-capita growth rate. By contrast, dispersal may raise a metapopulation's extinction risk by reducing its average population density. Which effect prevails is controlled by habitat fragmentation. Dispersal in mildly fragmented habitat reduces a metapopulation's extinction risk by raising its average per-capita growth rate without causing any appreciable drop in its average population density. By contrast, dispersal in severely fragmented habitat raises a metapopulation's extinction risk because the rise in its average per-capita growth rate is more than offset by the decline in its average population density. The metapopulation model used here shows several other interesting phenomena. Dispersal in sufficiently fragmented habitat reduces a metapopulation's extinction risk to that of a constant environment. Dispersal between habitat fragments reduces a metapopulation's extinction risk insofar as local environments are asynchronous. Grouped dispersal raises the effective habitat fragmentation level. Dispersal search barriers raise metapopulation extinction risk. Nonuniform dispersal may reduce the effective fraction of suitable habitat fragments below the extinction threshold. Nonuniform dispersal may make demographic stochasticity a more potent metapopulation extinction force than environmental stochasticity.
Dispersive approach to the axial anomaly and nonrenormalization theorem
International Nuclear Information System (INIS)
Pasechnik, R.S.; Teryaev, O.V.
2006-01-01
Anomalous triangle graphs for the divergence of the axial-vector current are studied using the dispersive approach generalized for the case of higher orders of perturbation theory. The validity of this procedure is proved up to the two-loop level. By direct calculation in the framework of dispersive approach we have obtained that the two-loop axial-vector-vector (AVV) amplitude is equal to zero. According to the Vainshtein's theorem, the transversal part of the anomalous triangle is not renormalized in the chiral limit. We generalize this theorem for the case of finite fermion mass in the triangle loop
International Nuclear Information System (INIS)
Katata, Genki; Ota, Masakazu; Terada, Hiroaki; Chino, Masamichi; Nagai, Haruyasu
2012-01-01
The atmospheric release of 131 I and 137 Cs in the early phase of the Fukushima Dai-ichi Nuclear Power Plant (FNPP1) accident from March 12 to 14, 2011 was estimated by combining environmental data with atmospheric dispersion simulations under the assumption of a unit release rate (1 Bq h −1 ). For the simulation, WSPEEDI-II computer-based nuclear emergency response system was used. Major releases of 131 I (>10 15 Bq h −1 ) were estimated when air dose rates increased in FNPP1 during the afternoon on March 12 after the hydrogen explosion of Unit 1 and late at night on March 14. The high-concentration plumes discharged during these periods flowed to the northwest and south–southwest directions of FNPP1, respectively. These plumes caused a large amount of dry deposition on the ground surface along their routes. Overall, the spatial pattern of 137 Cs and the increases in the air dose rates observed at the monitoring posts around FNPP1 were reproduced by WSPEEDI-II using estimated release rates. The simulation indicated that air dose rates significantly increased in the south–southwest region of FNPP1 by dry deposition of the high-concentration plume discharged from the night of March 14 to the morning of March 15. - Highlights: ► Source term during the Fukushima Dai-ichi Nuclear Power Plant accident was estimated. ► Atmospheric dispersion simulation was carried out for estimation. ► Major releases were estimated in the afternoon on March 12 and the night on March 14. ► Air dose rate increased due to dry deposition during the night of March 14.
The distribution of copper in stream sediments in an anomalous stream near Steinkopf, Namaqualand
International Nuclear Information System (INIS)
De Bruin, D.
1987-01-01
Anomalous copper concentrations detected by the regional stream-sediment programme of the Geological Survey was investigated in a stream near Steinkopf, Namaqualand. A follow-up disclosed the presence of malachite mineralization. However, additional stream-sediment samples collected from the 'anomalous' stream revealed an erratic distribution of copper and also that the malachite mineralization had no direct effect on the copper distribution in the stream sediments. Low partial-extraction yields, together with X-ray diffraction analyses, indicated that dispersion is mainly mechanical and that the copper occurs as cations in the lattice of the biotite fraction of the stream sediments. (author). 8 refs., 5 figs., 1 tab
The distribution of copper in stream sediments in an anomalous stream near Steinkopf, Namaqualand
Energy Technology Data Exchange (ETDEWEB)
De Bruin, D
1987-01-01
Anomalous copper concentrations detected by the regional stream-sediment programme of the Geological Survey was investigated in a stream near Steinkopf, Namaqualand. A follow-up disclosed the presence of malachite mineralization. However, additional stream-sediment samples collected from the 'anomalous' stream revealed an erratic distribution of copper and also that the malachite mineralization had no direct effect on the copper distribution in the stream sediments. Low partial-extraction yields, together with X-ray diffraction analyses, indicated that dispersion is mainly mechanical and that the copper occurs as cations in the lattice of the biotite fraction of the stream sediments. (author). 8 refs., 5 figs., 1 tab.
Moenster, Mathias; Steinmeyer, Günter; Iliew, Rumen; Lederer, Falk; Petermann, Klaus
2006-11-15
For optical fibers exhibiting a radially symmetric refractive index profile, there exists an analytical relation that connects waveguide dispersion and the Petermann-II mode field radius. We extend the usefulness of this relation to the nonradially symmetric case of microstructure fibers in the anomalous dispersion regime, yielding a simple relation between dispersion and effective mode field area. Assuming a Gaussian mode distribution, we derive a fundamental upper limit for the effective mode field area that is required to obtain a certain amount of anomalous waveguide dispersion. This relation is demonstrated to show excellent agreement for fiber designs suited for supercontinuum generation and soliton lasers in the near infrared.
Dispersion tailoring of a silicon strip waveguide employing Titania-Alumina thin-film coating
DEFF Research Database (Denmark)
Guo, Kai; Christensen, Jesper B.; Christensen, Erik N.
2017-01-01
We numerically demonstrate dispersion tailoring of a silicon strip waveguide employing Titania-Alumina thin-film coating using a finite-difference mode solver. The proposed structure exhibits spectrally-flattened near-zero anomalous dispersion within the telecom wavelength range. We also numerica......We numerically demonstrate dispersion tailoring of a silicon strip waveguide employing Titania-Alumina thin-film coating using a finite-difference mode solver. The proposed structure exhibits spectrally-flattened near-zero anomalous dispersion within the telecom wavelength range. We also...
Anomalous properties of technetium clusters
International Nuclear Information System (INIS)
Kryuchkov, S.V.
1985-01-01
On the basis of critical evaluation of literature data in the field of chemistry of technetium cluster compounds with ligands of a weak field a conclusion is made on specific, ''anomalous'' properties of technetium cluster complexes which consist in an increased ability of the given element to the formation of a series of binuclear and multinuclear clusters, similar in composition and structure and easily transforming in each other. The majority of technetium clusters unlike similar compounds of other elements are paramagnetic with one unpaired electron on ''metallic'' MO of loosening type. All theoretical conceptions known today on the electronic structure of technetium clusters are considered. It is pointed out, that the best results in the explanation of ''anomalous'' properties of technetium clusters can be obtained in the framework of nonempirical methods of self-consistent field taking into account configuration interactions. It is also shown, that certain properties of technetium clusters can be explained on the basis of qualitative model of Coulomb repulsion of metal atoms in clusters. The conclusion is made, that technetium position in the Periodic table, as well as recently detected technetium property to the decrease of effective charge on its atoms during M-M bond formation promote a high ability of the element to cluster formation both with weak field ligands and with strong field one
Anomalous transport in toroidal plasmas
International Nuclear Information System (INIS)
Punjabi, A.
1989-12-01
When the magnetic moment of particle is conserved, there are three mechanisms which cause anomalous transport. These are: variation of magnetic field strength in flux surface, variation of electrostatic potential in flux surface, and destruction of flux surface. The anomalous transport of different groups of particles resulting from each of these mechanisms is different. This fact can be exploited to determine the cause of transport operative in an experimental situation. This approach can give far more information on the transport than the standard confinement time measurements. To implement this approach, we have developed Monte Carlo codes for toroidal geometries. The equations of motion are developed in a set of non-canonical, practical Boozer co-ordinates by means of Jacobian transformations of the particle drift Hamiltonian equations of motion. Effects of collisions are included by appropriate stochastic changes in the constants of motion. Effects of the loop voltage on particle motions are also included. We plan to apply our method to study two problems: the problem of the hot electron tail observed in edge region of ZT-40, and the energy confinement time in TOKAPOLE II. For the ZT-40 problem three situations will be considered: a single mode in the core, a stochastic region that covers half the minor radius, a stochastic region that covers the entire plasma. A turbulent spectrum of perturbations based on the experimental data of TOKAPOLE II will be developed. This will be used to simulate electron transport resulting from ideal instabilities and resistive instabilities in TOKAPOLE II
Anomalous transport in toroidal plasmas
International Nuclear Information System (INIS)
Punjabi, A.
1991-01-01
We have developed a Monte Carlo method to estimate the transport of different groups of particles for plasmas in toroidal geometries. This method can determine the important transport mechanisms driving the anomalous transport by comparing the numerical results with the experimental data. The important groups of particles whose transport can be estimated by this method include runaway electrons, thermal electrons, both passing and trapped diagnostic beam ions etc. The three basic mechanisms driving the anomalous transport are: spatial variation of magnetic field strength, spatial variation of electrostatic potential within the flux surfaces, and the loss of flux surfaces. The equation of motion are obtained from the drift hamiltonian. The equations of motion are developed in the canonical and in the non-canonical, practical co-ordinates as well. The effects of collisions are represented by appropriate stochastic changes in the constants of motion at each time-step. Here we present the results of application of this method to three cases: superathermal alphas in the rippled field of tokamaks, motion in the magnetic turbulence of takapole II, and transport in the stochastic fields of ZT40. This work is supported by DOE OFE and ORAU HBCU program
Geometry of physical dispersion relations
International Nuclear Information System (INIS)
Raetzel, Dennis; Rivera, Sergio; Schuller, Frederic P.
2011-01-01
To serve as a dispersion relation, a cotangent bundle function must satisfy three simple algebraic properties. These conditions are derived from the inescapable physical requirements that local matter field dynamics must be predictive and allow for an observer-independent notion of positive energy. Possible modifications of the standard relativistic dispersion relation are thereby severely restricted. For instance, the dispersion relations associated with popular deformations of Maxwell theory by Gambini-Pullin or Myers-Pospelov are not admissible. Dispersion relations passing the simple algebraic checks derived here correspond to physically admissible Finslerian refinements of Lorentzian geometry.
Wang, An; Fallah-Shorshani, Masoud; Xu, Junshi; Hatzopoulou, Marianne
2016-10-01
Near-road concentrations of nitrogen dioxide (NO2), a known marker of traffic-related air pollution, were simulated along a busy urban corridor in Montreal, Quebec using a combination of microscopic traffic simulation, instantaneous emission modeling, and air pollution dispersion. In order to calibrate and validate the model, a data collection campaign was designed. For this purpose, measurements of NO2 were conducted mid-block along four segments of the corridor throughout a four-week campaign conducted between March and April 2015. The four segments were chosen to be consecutive and yet exhibiting variability in road configuration and built environment characteristics. Roadside NO2 measurements were also paired with on-site and fixed-station meteorological data. In addition, traffic volumes, composition, and routing decisions were collected using video-cameras located at upstream and downstream intersections. Dispersion of simulated emissions was conducted for eight time slots and under a range of meteorological conditions using three different models with vastly different dispersion algorithms (OSPM, CALINE 4, and SIRANE). The three models exhibited poor correlation with near-road NO2 concentrations and were better able to simulate average concentrations occurring along the roadways rather than the range of concentrations measured under diverse meteorological and traffic conditions. As hypothesized, the model SIRANE that can handle a street canyon configuration was the most sensitive to the built environment especially to the presence of tall buildings around the road. In contrast, CALINE exhibited the lowest sensitivity to the built environment.
Rahsepar, Shokouhalsadat; Smit, Martijn P.J.; Murk, Albertinka J.; Rijnaarts, Huub H.M.; Langenhoff, Alette A.M.
2016-01-01
Chemical dispersants were used in response to the Deepwater Horizon oil spill in the Gulf of Mexico, both at the sea surface and the wellhead. Their effect on oil biodegradation is unclear, as studies showed both inhibition and enhancement. This study addresses the effect of Corexit on oil
Anomalous relaxation in binary mixtures: a dynamic facilitation picture
International Nuclear Information System (INIS)
Moreno, A J; Colmenero, J
2007-01-01
Recent computational investigations of polymeric and non-polymeric binary mixtures have reported anomalous relaxation features when both components exhibit very different mobilities. Anomalous relaxation is characterized by sublinear power-law behaviour for mean-squared displacements, logarithmic decay in dynamic correlators, and a striking concave-to-convex crossover in the latter by tuning the relevant control parameter, in analogy with predictions of the mode-coupling theory for state points close to higher-order transitions. We present Monte Carlo simulations on a coarse-grained model for relaxation in binary mixtures. The liquid structure is substituted by a three-dimensional array of cells. A spin variable is assigned to each cell, representing unexcited and excited local states of a mobility field. Changes in local mobility (spin flip) are permitted according to kinetic constraints determined by the mobilities of the neighbouring cells. We introduce two types of cell ('fast' and 'slow') with very different rates for spin flip. This coarse-grained model qualitatively reproduces the mentioned anomalous relaxation features observed for real binary mixtures
Anomalous osmosis resulting from preferential absorption
Staverman, A.J.; Kruissink, C.A.; Pals, D.T.F.
1965-01-01
An explanation of the anomalous osmosis described in the preceding paper is given in terms of friction coefficients in the glass membrane. It is shown that anomalous osmosis may be expected when the friction coefficients are constant and positive provided that the membrane absorbs solute strongly
Anomalous columnar order of charged colloidal platelets
Morales-Anda, L.; Wensink, H. H.; Galindo, A.; Gil-Villegas, A.
2012-01-01
Monte Carlo computer simulations are carried out for a model system of like-charged colloidal platelets in the isothermal-isobaric ensemble (NpT). The aim is to elucidate the role of electrostatic interactions on the structure of synthetic clay systems at high particle densities. Short-range repulsions between particles are described by a suitable hard-core model representing a discotic particle. This potential is supplemented with an electrostatic potential based on a Yukawa model for the screened Coulombic potential between infinitely thin disklike macro-ions. The particle aspect-ratio and electrostatic parameters were chosen to mimic an aqueous dispersion of thin, like-charged, rigid colloidal platelets at finite salt concentration. An examination of the fluid phase diagram reveals a marked shift in the isotropic-nematic transition compared to the hard cut-sphere reference system. Several statistical functions, such as the pair correlation function for the center-of-mass coordinates and structure factor, are obtained to characterize the structural organization of the platelets phases. At low salinity and high osmotic pressure we observe anomalous hexagonal columnar structures characterized by interpenetrating columns with a typical intercolumnar distance corresponding to about half of that of a regular columnar phase. Increasing the ionic strength leads to the formation of glassy, disordered structures consisting of compact clusters of platelets stacked into finite-sized columns. These so-called "nematic columnar" structures have been recently observed in systems of charge-stabilized gibbsite platelets. Our findings are corroborated by an analysis of the static structure factor from a simple density functional theory.
Localized vortices in ηi-modes
International Nuclear Information System (INIS)
Nycander, J.; Lynov, J.P.; Juul Rasmussen, J.
1992-01-01
For a wide variety of nonlinear wave equations necessary conditions for the existence of localized, stationary structures can be found by applying a simple procedure, involving two steps: First the linear dispersion relation is obtained and the regions of the phase velocity of linear waves found. Secondly, assuming that localized solutions exist, their velocities are determined by using integral relations. The obtained velocity takes the form of a ''center of mass velocity''. If this velocity falls outside the regions of phase velocities for linear waves then nonlinear localized vortices may exist. Otherwise, the structure will couple to the linear waves and gradually disperse. Applying this method we have shown that monopole vortex solutions exist for drift waves driven by the ion temperature gradient in a magnetized plasma, the so-called η i -modes. Numerical solutions show that such vortices are steadily propagating and stable and they generally emerge from localized initial conditions. Our study is motivated by recent high resolution simulations of η i -turbulence, where it was observed that coherent vortices developed spontaneously. These had a dominating influence on the evolution of the turbulence, and the associated anomalous transport was found to be significantly reduced as compared with the predictions from quasilinear theory. (author) 8 refs., 3 figs
Anomalous transport in mirror systems
International Nuclear Information System (INIS)
Post, R.F.
1979-01-01
As now being explored for fusion applications confinement systems based on the mirror principle embody two kinds of plasma regimes. These two regimes are: (a) high-beta plasmas, stabilized against MHD and other low frequency plasma instabilities by magnetic-well fields, but characterized by non-Maxwellian ion distributions; (b) near-Maxwellian plasmas, confined electrostatically (as in the tandem mirror) or in a field-reversed region within the mirror cell. Common to both situations are the questions of anomalous transport owing to high frequency instabilities in the non-maxwellian portions of the plasmas. This report will summarize the status of theory and of experimental data bearing on these questions, with particular reference to the high temperature regimes of interest for fusion power
Fluctuation relations for anomalous dynamics
International Nuclear Information System (INIS)
Chechkin, A V; Klages, R
2009-01-01
We consider work fluctuation relations (FRs) for generic types of dynamics generating anomalous diffusion: Lévy flights, long-correlated Gaussian processes and time-fractional kinetics. By combining Langevin and kinetic approaches we calculate the probability distributions of mechanical and thermodynamical work in two paradigmatic nonequilibrium situations, respectively: a particle subject to a constant force and a particle in a harmonic potential dragged by a constant force. We check the transient FR for two models exhibiting superdiffusion, where a fluctuation-dissipation relation does not exist, and for two other models displaying subdiffusion, where there is a fluctuation-dissipation relation. In the two former cases the conventional transient FR is not recovered, whereas in the latter two it holds either exactly or in the long-time limit. (letter)
Dinotor model for anomalous nuclei
International Nuclear Information System (INIS)
Castillejo, L.; Goldhaber, A.S.; Jackson, A.D.; Johnson, M.B.
1986-01-01
The simplest version of the MIT bag model implies the existence of metastable toroidal bags, with large radius proportional to the enclosed baryon number, and small radius comparable to that of an ordinary nucleon (we refer to those toroidal bags as dinotors). Considerations of various possible instabilities, and of the effects of quark interactions through intermediate gluons, suggest that the metastability is still valid when the model is treated more realistically. These results might provide an explanation for reports of anomalously large interaction cross sections of secondary fragments (''anomalons'') observed in visual track detectors. However, it appears that the most likely characteristics of toroidal bags would not be compatible with those of anomalons, and would not be as easy to detect in emulsions. copyright 1986 Academic Press, Inc
DEFF Research Database (Denmark)
Frosz, Michael Henoch; Falk, Peter Andreas; Bang, Ole
2007-01-01
An erratum is presented explaining that the observation in the original paper (Optics Express, volume 13, issue 16, page 6181-6192, 2005), of a bright-bright soliton with one color in the anomalous dispersion region and the other color in the normal dispersion region was mistaken; both parts...
Linear algebraic analyses of structures with one predominant type of anomalous scatterer
International Nuclear Information System (INIS)
Karle, J.
1989-01-01
Further studies have been made of the information content of the exact linear equations for analyzing anomalous dispersion data in one-wavelength experiments. The case of interest concerns structures containing atoms that essentially do not scatter anomalously and one type of anomalously scattering atoms. For this case, there are three alternative ways of writing the equations. The alternative sets of equations and the transformations for transforming one set into the other are given explicitly. Comparison calculations were made with different sets of equations. Isomorphous replacement information is readily introduced into the calculations and the advantage of doing so is clearly illustrated by the results. Another aspect of the potential of the exact linear algebraic theory is its application to multiple-wavelength experiments. Successful applications of the latter have been made by several collaborative groups of investigators. (orig.)
Scaling of anomalous hall effect in amorphous CoFeB Films with accompanying quantum correction
Zhang, Yan
2015-05-08
Scaling of anomalous Hall effect in amorphous CoFeB films with thickness ranging from 2 to 160 nm have been investigated. We have found that the scaling relationship between longitudinal (ρxx) and anomalous Hall (ρAH) resistivity is distinctly different in the Bloch and localization regions. For ultrathin CoFeB films, the sheet resistance (Rxx) and anomalous Hall conductance (GAH) received quantum correction from electron localization showing two different scaling relationships at different temperature regions. In contrast, the thicker films show a metallic conductance, which have only one scaling relationship in the entire temperature range. Furthermore, in the dirty regime of localization regions, an unconventional scaling relationship View the MathML sourceσAH∝σxxα with α=1.99 is found, rather than α=1.60 predicted by the unified theory.
Anomalous metal concentrations in soil and till at the Ballinalack Zn-Pb deposit, Ireland
Kalveram, Ann-Kristin; McClenaghan, Seán H.; Kamber, Balz S.
2017-04-01
Metals such as zinc, iron, arsenic and lead are commonly found in low concentrations within soils. These signatures may occur as a result of natural dispersion from metal-bearing geological formations and (or) from anthropogenic sources. Prior to investigating any high or anomalous concentrations of metals in the surficial environment, it is important to reconcile potential sources of metals and verify whether element anomalies are in response to buried mineralization. Here we show how to distinguish true elevated concentrations from naturally occurring variations within a soil system. The research area is situated above the limestone-hosted Ballinalack Zn-Pb deposit in the central Irish Midlands. To investigate the pedogenesis and its related geochemical signature, top of the till and the BC soil horizon were sampled. Although the area can be described as pasture land, it does not preclude previous anthropogenic influences from former agricultural use and local small scale peat harvesting. For the soil BC horizon as well as in the top of the till, aqua regia-digestible element concentrations vary significantly and locally reach anomalous levels: Zn (median: 104 ppm; range: 27 - 13150 ppm), Pb (median: 16 ppm; range: 2 - 6430 ppm), As (median: 7.7 ppm; range: 1.4 - 362 ppm), Ag (median: 0.12 ppm; range: 0.04 - 19.9 ppm), Ba (median: 40 ppm; range: 10 - 1230 ppm), Cd (median: 1.5 ppm; range: 0.2 - 68 ppm), Co (median: 7.3 ppm; range: 0.5 - 22 ppm), Ni (median: 37 ppm; range: 3 - 134 ppm), Fe (median: 17900 ppm; range: 5000 - 52300 ppm), Ga (median: 2.4 ppm; range: 0.3 - 7.6 ppm), Sb (median: 1.2 ppm; range: 0.1 - 197 ppm) and Tl (median: 0.3 ppm; range: 0.02 - 8.6 ppm). Comparison with background levels from the area and grouped according to underlying geology, enrichment factor calculations (against Nb and Zr) indicate an elemental response to metalliferous-bearing bedrock. These results confirm that soil anomalies of Zn, Pb, As, Ag, Ba, Cd, Ni, Sb and Tl, are
Dispersive effects in radiation transport and radiation hydrodynamics in matter at high density
International Nuclear Information System (INIS)
Crowley, B.J.B.
1983-01-01
In a recent research program (reported in AWRE 0 20/82) I have investigated the generalisation of the equations of radiation hydrodynamics when electromagnetic radiation is assumed to obey a linear-response dispersion relation of the form nω=kc where the refractive index n depends on the frequency ω and/or wave number k. From the application of the Boltzmann-Liouville transport theory to photons in the short-wavelength (geometrical optics) limit, I derive the energy and momentum equations which, when combined with a classical (Euler-Lagrange-Navier-Stokes) treatment of a fluid material medium in LTE, yield a complete dynamical theory of linear interactions (+ stimulated processes) between incoherent (thermal) radiation and dense, locally isotropic matter. The theory includes an account of pondero-motive forces and electro (magneto) striction. Moreover, it is apparently capable of being generalised to non-linear interactions in which the refractive index depends on the local specific intensity of the radiation field, and, to some extent, to the treatment of high-frequency coherent radiation. The generalisation of various approximated forms of radiation-transport theory (esp. diffusion) has been considered in detail. Some problems remain however. One such is the treatment of anomalous dispersion. Current research work is concentrating on the interesting atomic physics aspects of electromagnetic (esp. radiative) properties of a dispersive material medium
Anomalous Transport of Cosmic Rays in a Nonlinear Diffusion Model
Energy Technology Data Exchange (ETDEWEB)
Litvinenko, Yuri E. [Department of Mathematics, University of Waikato, P. B. 3105, Hamilton 3240 (New Zealand); Fichtner, Horst; Walter, Dominik [Institut für Theoretische Physik IV, Ruhr-Universität Bochum, Universitätsstrasse 150, D-44780 Bochum (Germany)
2017-05-20
We investigate analytically and numerically the transport of cosmic rays following their escape from a shock or another localized acceleration site. Observed cosmic-ray distributions in the vicinity of heliospheric and astrophysical shocks imply that anomalous, superdiffusive transport plays a role in the evolution of the energetic particles. Several authors have quantitatively described the anomalous diffusion scalings, implied by the data, by solutions of a formal transport equation with fractional derivatives. Yet the physical basis of the fractional diffusion model remains uncertain. We explore an alternative model of the cosmic-ray transport: a nonlinear diffusion equation that follows from a self-consistent treatment of the resonantly interacting cosmic-ray particles and their self-generated turbulence. The nonlinear model naturally leads to superdiffusive scalings. In the presence of convection, the model yields a power-law dependence of the particle density on the distance upstream of the shock. Although the results do not refute the use of a fractional advection–diffusion equation, they indicate a viable alternative to explain the anomalous diffusion scalings of cosmic-ray particles.
International Nuclear Information System (INIS)
Pietrzyk, M.E.
1999-02-01
Properties of two pulses propagating simultaneously in different dispersion regimes, anomalous and normal, in a Kerr-type planar waveguide are studied. It is found that the presence of the pulse propagating in normal dispersion regime can cause termination of catastrophic self-focusing of the pulse propagating in anomalous regime. It is also shown that the coupling between pulses can lead to spatio-temporal splitting of the pulse propagating in anomalous dispersion regime, but it does not lead to catastrophic self-focusing of the pulse propagating in normal dispersion regime. For the limiting case when the dispersive term of the pulse propagating in normal dispersion regime can be neglected an indication (based on the variational estimation) to a possibility of a stable self-trapped propagation of both pulses is obtained. This stabilization is similar to the one which was found earlier in media with saturation-type nonlinearity. (author)
DEFF Research Database (Denmark)
Guo, Kai; Christensen, Jesper Bjerge; Shi, Xiaodong
2018-01-01
We propose a silicon strip waveguide structure with alumina thin-film coating in-between the core and the cladding for group-velocity dispersion tailoring. By carefully designing the core dimension and the coating thickness, a spectrally-flattened near-zero anomalous group-velocity dispersion...
Hang, Tian; Chen, Hui-Jiuan; Wang, Ji; Lin, Di-an; Wu, Jiangming; Liu, Di; Cao, Yuhong; Yang, Chengduan; Liu, Chenglin; Xiao, Shuai; Gu, Meilin; Pan, Shuolin; Wu, Mei X.; Xie, Xi
2018-05-01
Dispersion of hydrophilic particles in non-polar media has many important applications yet remains difficult. Surfactant or amphiphilic functionalization was conventionally applied to disperse particles but is highly dependent on the particle/solvent system and may induce unfavorable effects and impact particle hydrophilic nature. Recently 2 μm size polystyrene microbeads coated with ZnO nanospikes have been reported to display anomalous dispersity in phobic media without using surfactant or amphiphilic functionalization. However, due to the lack of understanding whether this phenomenon was applicable to a wider range of conditions, little application has been derived from it. Here the anomalous dispersity phenomenons of hydrophilic microparticles covered with nanospikes were systematically assessed at various conditions including different particle sizes, material compositions, particle morphologies, solvent hydrophobicities, and surface polar groups. Microparticles were functionalized with nanospikes through hydrothermal route, followed by dispersity test in hydrophobic media. The results suggest nanospikes consistently prevent particle aggregation in various particle or solvent conditions, indicating the universal applicability of the anomalous dispersion phenomenons. This work provides insight on the anomalous dispersity of hydrophilic particles in various systems and offers potential application to use this method for surfactant-free dispersions.
Anomalous magnetic moment with heavy virtual leptons
Energy Technology Data Exchange (ETDEWEB)
Kurz, Alexander [Karlsruher Institut fuer Technologie (Germany). Inst. fuer Theoretische Teilchenphysik; Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Liu, Tao; Steinhauser, Matthias [Karlsruher Institut fuer Technologie (Germany). Inst. fuer Theoretische Teilchenphysik; Marquard, Peter [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)
2013-11-15
We compute the contributions to the electron and muon anomalous magnetic moment induced by heavy leptons up to four-loop order. Asymptotic expansion is applied to obtain three analytic expansion terms which show rapid convergence.
Tunneling Anomalous and Spin Hall Effects.
Matos-Abiague, A; Fabian, J
2015-07-31
We predict, theoretically, the existence of the anomalous Hall effect when a tunneling current flows through a tunnel junction in which only one of the electrodes is magnetic. The interfacial spin-orbit coupling present in the barrier region induces a spin-dependent momentum filtering in the directions perpendicular to the tunneling current, resulting in a skew tunneling even in the absence of impurities. This produces an anomalous Hall conductance and spin Hall currents in the nonmagnetic electrode when a bias voltage is applied across the tunneling heterojunction. If the barrier is composed of a noncentrosymmetric material, the anomalous Hall conductance and spin Hall currents become anisotropic with respect to both the magnetization and crystallographic directions, allowing us to separate this interfacial phenomenon from the bulk anomalous and spin Hall contributions. The proposed effect should be useful for proving and quantifying the interfacial spin-orbit fields in metallic and metal-semiconductor systems.
Anomalous neutron scattering and feroelectric modes
International Nuclear Information System (INIS)
Viswanathan, K.S.
1977-01-01
It is suggested that anomalous neutron scattering could prove a powerful experimental tool in studying ferroelectric phase transition, the sublattice displacements of the soft modes as well as their symmetry characteristics. (author)
Employment Effects of Spatial Dispersal of Refugees
DEFF Research Database (Denmark)
Damm, Anna Piil; Rosholm, Michael
We argue that spatial dispersal influences labour market assimilation of refugees through two mechanisms: first, the local job offer arrival rate and, second, place utility. Our partial search model with simultaneous job and residential location search predicts that the reservation wage for local...... by evaluating the employment effects of the Danish spatial dispersal policy carried out 1986-1998....
Velocity Dispersions Across Bulge Types
International Nuclear Information System (INIS)
Fabricius, Maximilian; Bender, Ralf; Hopp, Ulrich; Saglia, Roberto; Drory, Niv; Fisher, David
2010-01-01
We present first results from a long-slit spectroscopic survey of bulge kinematics in local spiral galaxies. Our optical spectra were obtained at the Hobby-Eberly Telescope with the LRS spectrograph and have a velocity resolution of 45 km/s (σ*), which allows us to resolve the velocity dispersions in the bulge regions of most objects in our sample. We find that the velocity dispersion profiles in morphological classical bulge galaxies are always centrally peaked while the velocity dispersion of morphologically disk-like bulges stays relatively flat towards the center--once strongly barred galaxies are discarded.
Anomalous Magnetic Excitations of Cooperative Tetrahedral Spin Clusters
DEFF Research Database (Denmark)
Prsa, K.; Rønnow, H.M.; Zaharko, O.
2009-01-01
An inelastic neutron scattering study of Cu2Te2O5X2 (X=Cl, Br) shows strong dispersive modes with large energy gaps persisting far above T-N, notably in Cu2Te2O5Br2. The anomalous features: a coexisting unusually weak Goldstone-like mode observed in Cu2Te2O5Cl2 and the size of the energy gaps can...... cannot be explained by existing theories, such as our mean-field or random-phase approximation. We argue that our findings represent a new general type of behavior due to intercluster quantum fluctuations and call for development of a new theoretical approach....
Soler, M. R.; Arasa, R.; Merino, M.; Olid, M.; Ortega, S.
2011-07-01
The structure and evolution of the sea breeze in the north-west part of the Mediterranean (Catalonia, north-east Spain) is studied both experimentally and, predominantly, using numerical models to increase understanding of sea-breeze structure and three-dimensional (3D) pollution distributions in coastal environments. Sea-breeze components are modelled and analyzed using the fifth-generation Pennsylvania State University-National Centre for Atmospheric Research Mesoscale Model (MM5). The results show that the growth and structure of the sea-breeze circulation is modulated by the synoptic flow and especially by the complex topography of the area. 3D pollution transport in a sea breeze is modelled by coupling the MM5 to the Community Multiscale Air Quality (CMAQ) model, with results indicating that topography and synoptic flow are the main factors modulating horizontal and vertical pollutant transport in sea-breeze episodes. In this way, horizontal dispersion is limited by the complex topography of the area, whilst the sea-breeze flow is intensified by anabatic upslope winds that contribute to vertical pollutant transport. The numerical model results also indicate that the sea-breeze circulation with a weak return flow at upper levels grows due to a synoptic onshore wind component. However, such a sea-breeze circulation is capable of transporting pollutants towards the coast.
Anomalous resistivity and the evolution of magnetic field topology
Parker, E. N.
1993-01-01
This paper explores the topological restructuring of a force-free magnetic field caused by the hypothetical sudden onset of a localized region of strong anomalous resistivity. It is shown that the topological complexity increases, with the primitive planar force-free field with straight field lines developing field lines that wrap half a turn around each other, evidently providing a surface of tangential discontinuity in the wraparound region. It is suggested that the topological restructuring contributes to the complexity of the geomagnetic substorm, the aurora, and perhaps some of the flare activity on the sun, or other star, and the Galactic halo.
Anomalous heat evolution of deuteron implanted Al on electron bombardment
International Nuclear Information System (INIS)
Kamada, K.; Kinoshita, H.; Takahashi, H.
1994-05-01
Anomalous heat evolution was observed in deuteron implanted Al foils on 175 keV electron bombardment. Local regions with linear dimension of several 100nm showed simultaneous transformation from single crystalline to polycrystalline structure instantaneously on the electron bombardment, indicating the temperature rise up to more than melting point of Al from room temperature. The amount of energy evolved was more than 180 MeV for each transformed region. The transformation was never observed in proton implanted Al foils. The heat evolution was considered due to a nuclear reaction in D 2 molecular collections. (author)
International Nuclear Information System (INIS)
Scattergood, R.O.; Das, E.S.P.
1976-01-01
Using digital computer-based methods, models for dispersion strengthening can now be developed which take into account many of the important effects that have been neglected in the past. In particular, the self interaction of a dislocation can be treated, and a computer simulation method was developed to determine the flow stress of a random distribution of circular, impenetrable obstacles, taking into account all such interactions. The flow stress values depended on the obstacle sizes and spacings, over and above the usual 1/L dependence where L is the average obstacle spacing. From an analysis of the results, it was found that the main effects of the self interactions can be captured in a line tension analogue in which the obstacles appear to be penetrable
Ristić, Davor; Mazzola, Maurizio; Chiappini, Andrea; Rasoloniaina, Alphonse; Féron, Patrice; Ramponi, Roberta; Righini, Giancarlo C; Cibiel, Gilles; Ivanda, Mile; Ferrari, Maurizio
2014-09-01
The modal dispersion of a whispering gallery mode (WGM) resonator is a very important parameter for use in all nonlinear optics applications. In order to tailor the WGM modal dispersion of a microsphere, we have coated a silica microsphere with a high-refractive-index coating in order to study its effect on the WGM modal dispersion. We used Er(3+) ions as a probe for a modal dispersion assessment. We found that, by varying the coating thickness, the geometrical cavity dispersion can be used to shift overall modal dispersion in a very wide range in both the normal and anomalous dispersion regime.
Veale, Melanie; Ma, Chung-Pei; Thomas, Jens; Greene, Jenny E.; McConnell, Nicholas J.; Walsh, Jonelle; Ito, Jennifer; Blakeslee, John P.; Janish, Ryan
2017-01-01
We present spatially resolved two-dimensional stellar kinematics for the 41 most massive early-type galaxies (ETGs; MK ≲ -25.7 mag, stellar mass M* ≳ 1011.8 M⊙) of the volume-limited (D McDonald Observatory, covering a 107 arcsec × 107 arcsec field of view (often reaching 2 to 3 effective radii). We measure the 2D spatial distribution of each galaxy's angular momentum (λ and fast or slow rotator status), velocity dispersion (σ), and higher order non-Gaussian velocity features (Gauss-Hermite moments h3 to h6). Our sample contains a high fraction (˜80 per cent) of slow and non-rotators with λ ≲ 0.2. When combined with the lower mass ETGs in the ATLAS3D survey, we find the fraction of slow rotators to increase dramatically with galaxy mass, reaching ˜50 per cent at MK ˜ -25.5 mag and ˜90 per cent at MK ≲ -26 mag. All of our fast rotators show a clear anticorrelation between h3 and V/σ, and the slope of the anticorrelation is steeper in more round galaxies. The radial profiles of σ show a clear luminosity and environmental dependence: the 12 most luminous galaxies in our sample (MK ≲ -26 mag) are all brightest cluster/group galaxies (except NGC 4874) and all have rising or nearly flat σ profiles, whereas five of the seven `isolated' galaxies are all fainter than MK = -25.8 mag and have falling σ. All of our galaxies have positive average h4; the most luminous galaxies have average h4 ˜ 0.05, while less luminous galaxies have a range of values between 0 and 0.05. Most of our galaxies show positive radial gradients in h4, and those galaxies also tend to have rising σ profiles. We discuss the implications for the relationship among dynamical mass, σ, h4, and velocity anisotropy for these massive galaxies.
Wave power balance in resonant dissipative media with spatial and temporal dispersion
International Nuclear Information System (INIS)
Tokman, M.D.; Gavrilova, M.A.; Westerhof, E. . www.rijnh.nl
2003-01-01
A power balance for waves in resonant dissipative media is formulated, which generalizes well-known expressions for dielectric wave energy density, wave energy flux, and dissipated power density. The identification of the different terms with wave energy density and flux remains only phenomenological. The result is better viewed as an equation for the evolution of wave intensity. In that form, its consequences are discussed in particular in relation to anomalous dispersion. A discrimination is made between boundary and initial value problems. For boundary value problems, anomalous dispersion is shown not to lead to unphysical results. In contrast, for initial value problems the solution for the evolution of wave intensity is shown to be at fault in the case of anomalous dispersion. Further illustration is provided by consideration of wave dispersion in a medium of charged harmonic oscillators and of ordinary-mode dispersion in plasma. Both are characterized by anomalous dispersion and show marked differences in the solutions of the dispersion relation solved either for complex wave vector at real frequency, k(ω) (applicable to boundary value problems), or for complex frequency at real wave vector ω(k) (applicable to initial value problems). (author)
International Nuclear Information System (INIS)
Pryce, M.H.L.
1985-01-01
A dominant mechanism contributing to hydrodynamic dispersion in fluid flow through rocks is variation of travel speeds within the channels carrying the fluid, whether these be interstices between grains, in granular rocks, or cracks in fractured crystalline rocks. The complex interconnections of the channels ensure a mixing of those parts of the fluid which travel more slowly and those which travel faster. On a macroscopic scale this can be treated statistically in terms of the distribution of times taken by a particle of fluid to move from one surface of constant hydraulic potential to another, lower, potential. The distributions in the individual channels are such that very long travel times make a very important contribution. Indeed, while the mean travel time is related to distance by a well-defined transport speed, the mean square is effectively infinite. This results in an asymmetrical plume which differs markedly from a gaussian shape. The distribution of microscopic travel times is related to the distribution of apertures in the interstices, or in the microcracks, which in turn are affected in a complex way by the stresses acting on the rock matrix
Gyrokinetic electron acceleration in the force-free corona with anomalous resistivity
Arzner, Kaspar; Vlahos, Loukas
2006-01-01
We numerically explore electron acceleration and coronal heating by dissipative electric fields. Electrons are traced in linear force-free magnetic fields extrapolated from SOHO/MDI magnetograms, endowed with anomalous resistivity ($\\eta$) in localized dissipation regions where the magnetic twist $\
Employment Effects of Spatial Dispersal of Refugees
Damm, Anna Piil; Rosholm, Michael
2005-01-01
We argue that spatial dispersal influences labour market assimilation of refugees through two mechanisms: first, the local job offer arrival rate and, second, place utility. Our partial search model with simultaneous job and residential location search predicts that the reservation wage for local jobs decreases with place utility. We argue that spatial dispersal decreases average place utility of refugees which decreases the transition rate into first job due to large local reservation wages....
Anomalous magnetohydrodynamics in the extreme relativistic domain
Giovannini, Massimo
2016-01-01
The evolution equations of anomalous magnetohydrodynamics are derived in the extreme relativistic regime and contrasted with the treatment of hydromagnetic nonlinearities pioneered by Lichnerowicz in the absence of anomalous currents. In particular we explore the situation where the conventional vector currents are complemented by the axial-vector currents arising either from the pseudo Nambu-Goldstone bosons of a spontaneously broken symmetry or because of finite fermionic density effects. After expanding the generally covariant equations in inverse powers of the conductivity, the relativistic analog of the magnetic diffusivity equation is derived in the presence of vortical and magnetic currents. While the anomalous contributions are generally suppressed by the diffusivity, they are shown to disappear in the perfectly conducting limit. When the flow is irrotational, boost-invariant and with vanishing four-acceleration the corresponding evolution equations are explicitly integrated so that the various physic...
The vector meson with anomalous magnetic moment
International Nuclear Information System (INIS)
Boyarkin, O.M.
1976-01-01
The possibility of introducing an anomalous magnetic moment into the Stuckelberg version of the charged vector meson theory is considered. It is shown that the interference of states with spins equal to one and zero is absent in the presence of an anomalous magnetic moment of a particle. The differential cross section of scattering on the Coulomb field of a nucleus is calculated, and so are the differential and integral cross sections of meson pair production on annihilation of two gamma quanta. The two-photon mechanism of production of a meson pair in colliding electron-positron beams is considered. It is shown that with any value of the anomalous magnetic moment the cross section of the esup(+)esup(-) → esup(+)esup(-)γsup(*)γsup(*) → esup(+)esup(-)Wsup(+)Wsup(-) reaction exceeds that of the esup(+)esup(-) → γsup(*) → Wsup(+)Wsup(-) at sufficiently high energies
The anomalous magnetic moment of the muon
Jegerlehner, Friedrich
2017-01-01
This research monograph covers extensively the theory of the muon anomalous magnetic moment and provides estimates of the theoretical uncertainties. The muon anomalous magnetic moment is one of the most precisely measured quantities in elementary particle physics and provides one of the most stringent tests of relativistic quantum field theory as a fundamental theoretical framework. It allows for an extremely precise check of the standard model of elementary particles and of its limitations. This book reviews the present state of knowledge of the anomalous magnetic moment a=(g-2)/2 of the muon. Recent experiments at the Brookhaven National Laboratory now reach the unbelievable precision of 0.5 parts per million, improving the accuracy of previous g-2 experiments at CERN by a factor of 14. In addition, quantum electrodynamics and electroweak and hadronic effects are reviewed. Since non-perturbative hadronic effects play a key role for the precision test, their evaluation is described in detail. Perspectives fo...
Total least squares for anomalous change detection
Theiler, James; Matsekh, Anna M.
2010-04-01
A family of subtraction-based anomalous change detection algorithms is derived from a total least squares (TLSQ) framework. This provides an alternative to the well-known chronochrome algorithm, which is derived from ordinary least squares. In both cases, the most anomalous changes are identified with the pixels that exhibit the largest residuals with respect to the regression of the two images against each other. The family of TLSQbased anomalous change detectors is shown to be equivalent to the subspace RX formulation for straight anomaly detection, but applied to the stacked space. However, this family is not invariant to linear coordinate transforms. On the other hand, whitened TLSQ is coordinate invariant, and special cases of it are equivalent to canonical correlation analysis and optimized covariance equalization. What whitened TLSQ offers is a generalization of these algorithms with the potential for better performance.
Fractional diffusion equations and anomalous diffusion
Evangelista, Luiz Roberto
2018-01-01
Anomalous diffusion has been detected in a wide variety of scenarios, from fractal media, systems with memory, transport processes in porous media, to fluctuations of financial markets, tumour growth, and complex fluids. Providing a contemporary treatment of this process, this book examines the recent literature on anomalous diffusion and covers a rich class of problems in which surface effects are important, offering detailed mathematical tools of usual and fractional calculus for a wide audience of scientists and graduate students in physics, mathematics, chemistry and engineering. Including the basic mathematical tools needed to understand the rules for operating with the fractional derivatives and fractional differential equations, this self-contained text presents the possibility of using fractional diffusion equations with anomalous diffusion phenomena to propose powerful mathematical models for a large variety of fundamental and practical problems in a fast-growing field of research.
Anomalous vibrational modes in acetanilide: A F.D.S. incoherent inelastic neutron scattering study
International Nuclear Information System (INIS)
Barthes, M.; Moret, J.; Eckert, J.; Johnson, S.W.; Swanson, B.I.; Unkefer, C.J.
1991-01-01
The origin of the anomalous infra-red and Raman modes in acetanilide (C 6 H 5 NHCOCH 3 , or ACN), remains a subject of considerable controversy. One family of theoretical models involves Davydov-like solitons nonlinear vibrational coupling, or ''polaronic'' localized modes. An alternative interpretation of the extra-bands in terms of a Fermi resonance was proposed and recently the existence of slightly non-degenerate hydrogen atom configurations in the H-bond was suggested as an explanation for the anomalies. In this paper we report some new results on the anomalous vibrational modes in ACN that were obtained by inelastic incoherent neutron scattering (INS)
Development of anomalous detection using movie prediction
International Nuclear Information System (INIS)
Sakakibara, Yoji; Demachi, Kazuyuki; Kawai, Masaki; Chhatluli, Ritu; Kamiaka, Kazuma
2012-01-01
In this research, the new method to predict the near-future of the movie images captured by video camera based on the combination of the Principle Component Analysis (PCA) and the Singular Spectral Analysis (SSA). In the normal condition of machines, the real-time captured movie is supposed to correspond to the predicted one. If the error between the both becomes significantly large, it may suggest some anomalous motion of the machines. So the movie prediction method has a possibility of the sensitive anomalous detection system. (author)
Wang, X; Chauvat, M-P; Ruterana, P; Walther, T
2017-12-01
We have applied our previous method of self-consistent k*-factors for absorption correction in energy-dispersive X-ray spectroscopy to quantify the indium content in X-ray maps of thick compound InGaN layers. The method allows us to quantify the indium concentration without measuring the sample thickness, density or beam current, and works even if there is a drastic local thickness change due to sample roughness or preferential thinning. The method is shown to select, point-by-point in a two-dimensional spectrum image or map, the k*-factor from the local Ga K/L intensity ratio that is most appropriate for the corresponding sample geometry, demonstrating it is not the sample thickness measured along the electron beam direction but the optical path length the X-rays have to travel through the sample that is relevant for the absorption correction. © 2017 The Authors Journal of Microscopy © 2017 Royal Microscopical Society.
On dispersive derivation of triangle anomaly
International Nuclear Information System (INIS)
Horejsi, J.
1985-01-01
A straightforward generalization of the results of some previous treatments, in which the Adler-Bell-Jachiw triangle anomaly has been recovered with the help of dispersion relation is presented. The absorptive part of the VVA triangle diagram with the external momenta k, p at vector vertices such as K 2 =p 2 =0 is considered. An integral of the imaginary part of the relevant invariant amplitude is calculated explicitly. It is shown that the anomalous contribution to the axial Ward identity is reproduced. This also enables one to demonstrate the delta-like behaviour of sich an imaginary part in k 2 → 0, m → 0 limit
DEFF Research Database (Denmark)
Pærregaard, Karsten
This book presents a comparative study of Peruvian transnational migration to the United States, Spain, Japan and Argentina. It applies a multi-sited ethnographic fieldwork approach to study is the multicultural life-world of Peruvians and the economic, social, political and ritual relations...... that link them together in a diasporic network across national boundaries and tie them to their country of origin. The book has three aims: 1) to examine how Peruvians create networks and design strategies to cope with the mechanisms of inclusion and exclusion that mediate their incorporation......). Analytically, the study operates on two levels. On the one hand, it draws on ethnographic data gathered in particular localities in the United States, Spain, Japan and Argentina to analyze a variety of issues such as livelihoods, family networks, religious institutions, migrant organizations, identity...
Middleton, Beth; van Diggelen, Rudy; Jensen, Kai
Question: How does seed dispersal reduce fen isolation and contribute to biodiversity? Location: European and North American fens. Methods: This paper reviews the literature on seed dispersal to fens. Results: Landscape fragmentation may reduce dispersal opportunities thereby isolating fens and
Anomalous Seebeck coefficient in boron carbides
International Nuclear Information System (INIS)
Aselage, T.L.; Emin, D.; Wood, C.; Mackinnon, I.D.R.; Howard, I.A.
1987-01-01
Boron carbides exhibit an anomalously large Seebeck coefficient with a temperature coefficient that is characteristic of polaronic hopping between inequivalent sites. The inequivalence in the sites is associated with disorder in the solid. The temperature dependence of the Seebeck coefficient for materials prepared by different techniques provides insight into the nature of the disorder
Examination of anomalous self-experience
DEFF Research Database (Denmark)
Raballo, Andrea; Parnas, Josef
2012-01-01
. Here, we present the initial normative data and psychometric properties of a newly developed instrument (Examination of Anomalous Self-experience [EASE]), specifically designed to support the psychopathological exploration of SDs in both research and "real world" clinical settings. Our results support...
Anomalous N=2 superconformal Ward identities
International Nuclear Information System (INIS)
Ketov, Sergei V.
2000-01-01
The N=2 superconformal Ward identities and their anomalies are discussed in N=2 superspace (including N=2 harmonic superspace), at the level of the low-energy effective action (LEEA) in four-dimensional N=2 supersymmetric field theories. The (first) chiral N=2 supergravity compensator is related to the known N=2 anomalous Ward identity in the N=2 (abelian) vector mulitplet sector. As regards the hypermultiplet LEEA given by the N=2 non-linear sigma-model (NLSM), a new anomalous N=2 superconformal Ward identity is found, whose existence is related to the (second) analytic compensator in N=2 supergravity. The celebrated solution of Seiberg and Witten is known to obey the (first) anomalous Ward identity in the Coulomb branch. We find a few solutions to the new anomalous Ward identity, after making certain assumptions about unbroken internal symmetries. Amongst the N=2 NLSM target space metrics governing the hypermultiplet LEEA are the SU(2)-Yang-Mills-Higgs monopole moduli-space metrics that can be encoded in terms of the spectral curves (Riemann surfaces), similarly to the Seiberg-Witten-type solutions. After a dimensional reduction to three spacetime dimensions (3d), our results support the mirror symmetry between the Coulomb and Higgs branches in 3d, N=4 gauge theories
Anomalous human behavior detection: An Adaptive approach
Leeuwen, C. van; Halma, A.; Schutte, K.
2013-01-01
Detection of anomalies (outliers or abnormal instances) is an important element in a range of applications such as fault, fraud, suspicious behavior detection and knowledge discovery. In this article we propose a new method for anomaly detection and performed tested its ability to detect anomalous
Anomalous VVH interactions at a linear collider
Indian Academy of Sciences (India)
Abstract. We examine, in a model independent way, the sensitivity of a linear collider to the couplings of a light Higgs boson to a pair of gauge bosons, including the possibility of. CP violation. We construct several observables that probe the various possible anomalous couplings. For an intermediate mass Higgs, a collider ...
Anomalous periodic disruptions in tokamak plasma
International Nuclear Information System (INIS)
Montvai, A.; Tegze, M.; Valyi, I.
1982-09-01
Anomalously strong, periodic instabilities were observed in the MT-1 tokamak. Characteristics of these instabilities were partly similar to those of internal disruptions, but there were features making them different from the normal relaxational oscillations. Basic characteristics of the phenomenon were studied with the aid of generally used diagnostics. (author)
Anomalous Hall effect in disordered multiband metals
Czech Academy of Sciences Publication Activity Database
Kovalev, A.A.; Sinova, Jairo; Tserkovnyak, Y.
2010-01-01
Roč. 105, č. 3 (2010), 036601/1-036601/4 ISSN 0031-9007 Institutional research plan: CEZ:AV0Z10100521 Keywords : anomalous Hall effect * spintronics Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 7.621, year: 2010
Anomalous VVH interactions at a linear collider
Indian Academy of Sciences (India)
We examine, in a model independent way, the sensitivity of a linear collider to the couplings of a light Higgs boson to a pair of gauge bosons, including the possibility of CP violation. We construct several observables that probe the various possible anomalous couplings. For an intermediate mass Higgs, a collider operating ...
Bunburra Rockhole: A New Anomalous Achondrite
Czech Academy of Sciences Publication Activity Database
Bland, P.A.; Spurný, Pavel; Greenwood, R.C.; Towner, M.C.; Bevan, A.W.R.; Bottke jr., W.F.; Shrbený, Lukáš; McClafferty, T.; Vaughan, D.; Benedix, G.K.; Franchi, I.A.; Hough, R.M.
2009-01-01
Roč. 72, Supplement (2009), A34-A34 ISSN 1086-9379. [Annual Meeting of the Meteoritical Society /72./. Nancy, 13.06.2009-18.06.2009] Institutional research plan: CEZ:AV0Z10030501 Keywords : Bunburra Rockhole * anomalous achondrite Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 3.253, year: 2009
Anomalous Levinson theorem and supersymmetric quantum mechanics
International Nuclear Information System (INIS)
Boya, L.J.; Casahorran, J.; Esteve, J.G.
1993-01-01
We analyse the symmetry breaking associated to anomalous realization of supersymmetry in the context of SUSY QM. In this case one of the SUSY partners is singular; that leads to peculiar forms of the Levinson theorem relating phase shifts and bound states. Some examples are exhibited; peculiarities include negative energies, incomplete pairing of states and extra phases in scattering. (Author) 8 refs
Anomalous high-frequency wave activity flux preceding anomalous changes in the Northern polar jet
Nakamura, Mototaka; Kadota, Minoru; Yamane, Shozo
2010-05-01
Anomalous forcing by quasi-geostrophic (QG) waves has been reported as an important forcing factor in the Northern Annular Mode (NAM) in recent literatures. In order to shed a light on the dynamics of the NAM from a different angle, we have examined anomalous behavior of the winter jets in the upper troposphere and stratosphere by focusing our diagnosis on not the anomalous geopotential height (Z) itself, but on the anomalous change in the Z (dZ) between two successive months and preceding transient QG wave activity flux during the cold season. We calculated EOFs of dZ between two successive months at 150hPa for a 46-year period, from 1958 to 2003, using the monthly mean NCEP reanalysis data. We then formed anomaly composites of changes in Z and the zonal velocity (U), as well as the preceding and following wave activity flux, Z, U, and temperature at various heights, for both positive and negative phases of the first EOF. For the wave forcing fields, we adopted the diagnostic system for the three-dimensional QG transient wave activity flux in the zonally-varying three-dimensional mean flow developed by Plumb (1986) with a slight modification in its application to the data. Our choice of the Plumb86 is based on the fact that the winter mean flow in the Northern Hemisphere is characterized by noticeable zonal asymmetry, and has a symbiotic relationship with waves in the extra-tropics. The Plumb86 flux was calculated for high-frequency (period of 2 to 7 days) and low-frequency (period of 10 to 20 days) waves with the ultra-low-frequency (period of 30 days or longer) flow as the reference state for each time frame of the 6 hourly NCEP reanalysis data from 1958 to 2003. By replacing the mean flow with the ultra-low-frequency flow in the application of the Plumb86 formula, the flux fields were calculated as time series at 6 hour intervals. The time series of the wave activity flux was then averaged for each month. The patterns of composited anomalous dZ and dU clearly
Interaction between molecular complexes in dispersive media
International Nuclear Information System (INIS)
Banagas, E.A.; Manykin, E.A.
1987-01-01
The interaction between molecular complexes in different dispersive media with local and nonlocal screening is investigated theoretically. On the basis of results of numerical analysis on a computer, the dependence of the coupled-system spectrum and the interaction energy of the polarized modes on the characteristic parameters of the dispersive media is considered
Anomalous moments of quarks and leptons from nonstandard WWγ couplings
International Nuclear Information System (INIS)
Boudjema, F.; Hagiwara, K.; Hamzaoui, C.; Numata, K.
1991-01-01
Contributions of nonstandard WWγ couplings to the four electromagnetic form factors of light quarks and leptons, magnetic and electric dipole moments, anapole moments, and charge radii, have been reevaluated, with a special emphasis on the effects of the locally SU(2) weak -invariant nonrenormalizable couplings λ and λ. Previous results for the contribution of the dimension-four anomalous couplings Δκ and κ are reproduced. The λ contribution to the charge radius and the anapole moments are found to be logarithmically sensitive to the cutoff scale (Λ), but the contribution of the λ coupling to the anomalous magnetic moments as well as that of the λ coupling to the electric dipole moments are found to be finite. These finite values are, however, found to be regularization-scheme dependent. The origin of the ambiguities is discussed and we argue that the numerical coefficients depend on the details of the underlying physics that gives rise to these nonstandard couplings. Banning an accidental cancellation, we can place an order-of-magnitude upper bound |λ|approx-lt 10 -4 from the experimental limit on the electric dipole moment of the neutron. Some definite predictions for the off-shell form factors are also presented
Anomalous quantum numbers and topological properties of field theories
International Nuclear Information System (INIS)
Polychronakos, A.P.
1987-01-01
We examine the connection between anomalous quantum numbers, symmetry breaking patterns and topological properties of some field theories. The main results are the following: In three dimensions the vacuum in the presence of abelian magnetic field configurations behaves like a superconductor. Its quantum numbers are exactly calculable and are connected with the Atiyah-Patodi-Singer index theorem. Boundary conditions, however, play a nontrivial role in this case. Local conditions were found to be physically preferable than the usual global ones. Due to topological reasons, only theories for which the gauge invariant photon mass in three dimensions obeys a quantization condition can support states of nonzero magnetic flux. For similar reasons, this mass induces anomalous angular momentum quantum numbers to the states of the theory. Parity invariance and global flavor symmetry were shown to be incompatible in such theories. In the presence of mass less flavored fermions, parity will always break for an odd number of fermion flavors, while for even fermion flavors it may not break but only at the expense of maximally breaking the flavor symmetry. Finally, a connection between these theories and the quantum Hall effect was indicated
Extreme coastal erosion enhanced by anomalous extratropical storm wave direction.
Harley, Mitchell D; Turner, Ian L; Kinsela, Michael A; Middleton, Jason H; Mumford, Peter J; Splinter, Kristen D; Phillips, Matthew S; Simmons, Joshua A; Hanslow, David J; Short, Andrew D
2017-07-20
Extratropical cyclones (ETCs) are the primary driver of large-scale episodic beach erosion along coastlines in temperate regions. However, key drivers of the magnitude and regional variability in rapid morphological changes caused by ETCs at the coast remain poorly understood. Here we analyze an unprecedented dataset of high-resolution regional-scale morphological response to an ETC that impacted southeast Australia, and evaluate the new observations within the context of an existing long-term coastal monitoring program. This ETC was characterized by moderate intensity (for this regional setting) deepwater wave heights, but an anomalous wave direction approximately 45 degrees more counter-clockwise than average. The magnitude of measured beach volume change was the largest in four decades at the long-term monitoring site and, at the regional scale, commensurate with that observed due to extreme North Atlantic hurricanes. Spatial variability in morphological response across the study region was predominantly controlled by alongshore gradients in storm wave energy flux and local coastline alignment relative to storm wave direction. We attribute the severity of coastal erosion observed due to this ETC primarily to its anomalous wave direction, and call for greater research on the impacts of changing storm wave directionality in addition to projected future changes in wave heights.
Boaretto, B. R. R.; Budzinski, R. C.; Prado, T. L.; Kurths, J.; Lopes, S. R.
2018-05-01
It is known that neural networks under small-world topology can present anomalous synchronization and nonstationary behavior for weak coupling regimes. Here, we propose methods to suppress the anomalous synchronization and also to diminish the nonstationary behavior occurring in weakly coupled neural network under small-world topology. We consider a network of 2000 thermally sensitive identical neurons, based on the model of Hodgkin-Huxley in a small-world topology, with the probability of adding non local connection equal to p = 0 . 001. Based on experimental protocols to suppress anomalous synchronization, as well as nonstationary behavior of the neural network dynamics, we make use of (i) external stimulus (pulsed current); (ii) biologic parameters changing (neuron membrane conductance changes); and (iii) body temperature changes. Quantification analysis to evaluate phase synchronization makes use of the Kuramoto's order parameter, while recurrence quantification analysis, particularly the determinism, computed over the easily accessible mean field of network, the local field potential (LFP), is used to evaluate nonstationary states. We show that the methods proposed can control the anomalous synchronization and nonstationarity occurring for weak coupling parameter without any effect on the individual neuron dynamics, neither in the expected asymptotic synchronized states occurring for large values of the coupling parameter.
Employment Effects of Spatial Dispersal of Refugees
DEFF Research Database (Denmark)
Damm, Anna Piil; Rosholm, Michael
Spatial dispersal policies may influence labour market integration of refugees through two mechanisms. First, it may affect the local job offer arrival rate, and second, it may affect place utility. We investigate the second mechanism theoretically by formulating a partial search model in which a...... due to large local reservation wage effects. We investigate both mechanisms empirically and test the predictions of the theoretical model by evaluating the employment effects of the Danish spatial dispersal policy carried out 1986-1998....
Lu, Ping; Moya, Jaime M; Yuan, Renliang; Zuo, Jian Min
2018-03-01
The delocalization of x-ray signals limits the spatial resolution in atomic-scale elemental mapping by scanning transmission electron microscopy (STEM) using energy-dispersive x-ray spectroscopy (EDS). In this study, using a SrTiO 3 [001] single crystal, we show that the x-ray localization to atomic columns is strongly dependent on crystal thickness, and a thin crystal is critical for improving the spatial resolution in atomic-scale EDS mapping. A single-frame scanning technique is used in this study instead of the multiple-frame technique to avoid peak broadening due to tracking error. The strong thickness dependence is realized by measuring the full width at half maxima (FWHM) as well as the peak-to-valley (P/V) ratio of the EDS profiles for Ti K and Sr K + L, obtained at several crystal thicknesses. A FWHM of about 0.16 nm and a P/V ratio of greater than 7.0 are obtained for Ti K for a crystal thickness of less than 20 nm. With increasing crystal thickness, the FWHM and P/V ratio increases and decreases, respectively, indicating the advantage of using a thin crystal for high-resolution EDS mapping. Published by Elsevier B.V.
International Nuclear Information System (INIS)
Sen, A.K.
1998-01-01
This final report is comprised of the following six progress reports: Ion Temperature Gradient Instability and Anomalous Transport, July 1989; Ion Temperature Gradient Instability and Anomalous Transport, August 1991; Ion Temperature Gradient Instability and Anomalous Transport, July 1993; Ion Anomalous Transport and Feedback Control, May 1994; Ion Anomalous Transport and Feedback Control, April 1995; and Ion Anomalous Transport and Feedback Control, December 1997
Anomalous radon emission as precursor of medium to strong earthquakes
Energy Technology Data Exchange (ETDEWEB)
Zoran, Maria [National Institute of R& D for Optoelectronics, MG5 Bucharest -Magurele, 077125 Romania (Romania)
2016-03-25
Anomalous radon (Rn{sup 222}) emissions enhanced by forthcoming earthquakes is considered to be a precursory phenomenon related to an increased geotectonic activity in seismic areas. Rock microfracturing in the Earth’s crust preceding a seismic rupture may cause local surface deformation fields, rock dislocations, charged particle generation and motion, electrical conductivity changes, radon and other gases emission, fluid diffusion, electrokinetic, piezomagnetic and piezoelectric effects as well as climate fluctuations. Space-time anomalies of radon gas emitted in underground water, soil and near the ground air weeks to days in the epicentral areas can be associated with the strain stress changes that occurred before the occurrence of medium and strong earthquakes. This paper aims to investigate temporal variations of radon concentration levels in air near or in the ground by the use of solid state nuclear track detectors (SSNTD) CR-39 and LR-115 in relation with some important seismic events recorded in Vrancea region, Romania.
A two-Lane model with anomalous slow dynamics
Linford, Dan; Richards, Trevor; Pleimling, Michel
2011-10-01
It is known that in one-dimensional equilibrium systems with short range interactions a phase transition cannot exist at finite, non-zero temperatures. However, far from equilibrium, one-dimensional systems with local interactions can exhibit a phase transition. The ABC model, a three species model defined on a chain characterized by non-symmetric exchanges between particles, is known to possess a non-equilibrium phase transition. This model exhibits anomalous slow dynamics that we investigate in some detail using two-time quantities. In addition we discuss an extension of this model to a case where this single lane is coupled to a one-dimensional particle bath. This coupling yields an additional phase transition that we discuss in some detail.
Tuning giant anomalous Hall resistance ratio in perpendicular Hall balance
Energy Technology Data Exchange (ETDEWEB)
Zhang, J. Y.; Yang, G. [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083 (China); State Key Laboratory of Magnetism, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Wang, S. G., E-mail: sgwang@iphy.ac.cn, E-mail: ghyu@mater.ustb.edu.cn [State Key Laboratory of Magnetism, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Liu, J. L. [State Key Laboratory of Magnetism, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Department of Physics, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China); Wang, R. M. [Department of Physics, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China); Amsellem, E.; Kohn, A. [Department of Materials Engineering, Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer-Sheva 84105 (Israel); Yu, G. H., E-mail: sgwang@iphy.ac.cn, E-mail: ghyu@mater.ustb.edu.cn [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083 (China)
2015-04-13
Anomalous Hall effect at room temperature in perpendicular Hall balance with a core structure of [Pt/Co]{sub 4}/NiO/[Co/Pt]{sub 4} has been tuned by functional CoO layers, where [Pt/Co]{sub 4} multilayers exhibit perpendicular magnetic anisotropy. A giant Hall resistance ratio up to 69 900% and saturation Hall resistance (R{sub S}{sup P}) up to 2590 mΩ were obtained in CoO/[Pt/Co]{sub 4}/NiO/[Co/Pt]{sub 4}/CoO system, which is 302% and 146% larger than that in the structure without CoO layers, respectively. Transmission electron microscopy shows highly textured [Co/Pt]{sub 4} multilayers and oxide layers with local epitaxial relations, indicating that the crystallographic structure has significant influence on spin dependent transport properties.
Resurgence of the cusp anomalous dimension
Energy Technology Data Exchange (ETDEWEB)
Dorigoni, Daniele; Hatsuda, Yasuyuki [DESY Theory Group, DESY Hamburg,Notkestrasse 85, D-22603 Hamburg (Germany)
2015-09-21
We revisit the strong coupling limit of the cusp anomalous dimension in planar N=4 super Yang-Mills theory. It is known that the strong coupling expansion is asymptotic and non-Borel summable. As a consequence, the cusp anomalous dimension receives non-perturbative corrections, and the complete strong coupling expansion should be a resurgent transseries. We reveal that the perturbative and non-perturbative parts in the transseries are closely interrelated. Solving the Beisert-Eden-Staudacher equation systematically, we analyze in detail the large order behavior in the strong coupling perturbative expansion and show that the non-perturbative information is indeed encoded there. An ambiguity of (lateral) Borel resummations of the perturbative expansion is precisely canceled by the contributions from the non-perturbative sectors, and the final result is real and unambiguous.
Resurgence of the Cusp Anomalous Dimension
Energy Technology Data Exchange (ETDEWEB)
Dorigoni, Daniele; Hatsuda, Yasuyuki [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany). Theory Group
2015-06-15
We revisit the strong coupling limit of the cusp anomalous dimension in planar N=4 super Yang-Mills theory. It is known that the strong coupling expansion is asymptotic and non-Borel summable. As a consequence, the cusp anomalous dimension receives non-perturbative corrections, and the complete strong coupling expansion should be a resurgent transseries. We reveal that the perturbative and non-perturbative parts in the transseries are closely interrelated. Solving the Beisert-Eden-Staudacher equation systematically, we analyze in detail the large order behavior in the strong coupling perturbative expansion and show that the non-perturbative information is indeed encoded there. An ambiguity of (lateral) Borel resummations of the perturbative expansion is precisely canceled by the contributions from the non-perturbative sectors, and the final result is real and unambiguous.
Resurgence of the Cusp Anomalous Dimension
International Nuclear Information System (INIS)
Dorigoni, Daniele; Hatsuda, Yasuyuki
2015-06-01
We revisit the strong coupling limit of the cusp anomalous dimension in planar N=4 super Yang-Mills theory. It is known that the strong coupling expansion is asymptotic and non-Borel summable. As a consequence, the cusp anomalous dimension receives non-perturbative corrections, and the complete strong coupling expansion should be a resurgent transseries. We reveal that the perturbative and non-perturbative parts in the transseries are closely interrelated. Solving the Beisert-Eden-Staudacher equation systematically, we analyze in detail the large order behavior in the strong coupling perturbative expansion and show that the non-perturbative information is indeed encoded there. An ambiguity of (lateral) Borel resummations of the perturbative expansion is precisely canceled by the contributions from the non-perturbative sectors, and the final result is real and unambiguous.
Anomalous properties of hot dense nonequilibrium plasmas
International Nuclear Information System (INIS)
Ferrante, G; Zarcone, M; Uryupin, S A
2005-01-01
A concise overview of a number of anomalous properties of hot dense nonequilibrium plasmas is given. The possibility of quasistationary megagauss magnetic field generation due to Weibel instability is discussed for plasmas created in atom tunnel ionization. The collisionless absorption and reflection of a test electromagnetic wave normally impinging on the plasma with two-temperature bi-maxwellian electron velocity distribution function are studied. Due to the wave magnetic field influence on the electron kinetics in the skin layer the wave absorption and reflection significantly depend on the degree of the electron temperature anisotropy. The linearly polarized impinging wave during reflection transforms into an elliptically polarized one. The problem of transmission of an ultrashort laser pulse through a layer of dense plasma, formed as a result of ionization of a thin foil, is considered. It is shown that the strong photoelectron distribution anisotropy yields an anomalous penetration of the wave field through the foil
Anomalous enthalpy relaxation in vitreous silica
DEFF Research Database (Denmark)
Yue, Yuanzheng
2015-01-01
scans. It is known that the liquid fragility (i.e., the speed of the viscous slow-down of a supercooled liquid at its Tg during cooling) has impact on enthalpy relaxation in glass. Here, we find that vitreous silica (as a strong system) exhibits striking anomalies in both glass transition and enthalpy...... relaxation compared to fragile oxide systems. The anomalous enthalpy relaxation of vitreous silica is discovered by performing the hyperquenching-annealing-calorimetry experiments. We argue that the strong systems like vitreous silica and vitreous Germania relax in a structurally cooperative manner, whereas...... the fragile ones do in a structurally independent fashion. We discuss the origin of the anomalous enthalpy relaxation in the HQ vitreous silica....
Anomalous feedback and negative domain wall resistance
International Nuclear Information System (INIS)
Cheng, Ran; Xiao, Di; Zhu, Jian-Gang
2016-01-01
Magnetic induction can be regarded as a negative feedback effect, where the motive-force opposes the change of magnetic flux that generates the motive-force. In artificial electromagnetics emerging from spintronics, however, this is not necessarily the case. By studying the current-induced domain wall dynamics in a cylindrical nanowire, we show that the spin motive-force exerting on electrons can either oppose or support the applied current that drives the domain wall. The switching into the anomalous feedback regime occurs when the strength of the dissipative torque β is about twice the value of the Gilbert damping constant α . The anomalous feedback manifests as a negative domain wall resistance, which has an analogy with the water turbine. (paper)
Anomalous diffusion of fermions in superlattices
International Nuclear Information System (INIS)
Drozdz, S.; Okolowicz, J.; Srokowski, T.; Ploszajczak, M.
1996-03-01
Diffusion of fermions in the periodic two-dimensional lattice of fermions is studied. It is shown that effects connected with antisymmetrization of the wave function increase chaoticness of motion. Various types of anomalous diffusion, characterized by a power spectral analysis are found. The nonlocality of the Pauli potential destroys cantori in the phase space. Consequently, the diffusion process is dominated by long free paths and the power spectrum is logarithmic at small frequency limit. (author)
What's wrong with anomalous chiral gauge theory?
International Nuclear Information System (INIS)
Kieu, T.D.
1994-05-01
It is argued on general ground and demonstrated in the particular example of the Chiral Schwinger Model that there is nothing wrong with apparently anomalous chiral gauge theory. If quantised correctly, there should be no gauge anomaly and chiral gauge theory should be renormalisable and unitary, even in higher dimensions and with non-Abelian gauge groups. Furthermore, it is claimed that mass terms for gauge bosons and chiral fermions can be generated without spoiling the gauge invariance. 19 refs
Anomalous Symmetry Fractionalization and Surface Topological Order
Directory of Open Access Journals (Sweden)
Xie Chen
2015-10-01
Full Text Available In addition to possessing fractional statistics, anyon excitations of a 2D topologically ordered state can realize symmetry in distinct ways, leading to a variety of symmetry-enriched topological (SET phases. While the symmetry fractionalization must be consistent with the fusion and braiding rules of the anyons, not all ostensibly consistent symmetry fractionalizations can be realized in 2D systems. Instead, certain “anomalous” SETs can only occur on the surface of a 3D symmetry-protected topological (SPT phase. In this paper, we describe a procedure for determining whether a SET of a discrete, on-site, unitary symmetry group G is anomalous or not. The basic idea is to gauge the symmetry and expose the anomaly as an obstruction to a consistent topological theory combining both the original anyons and the gauge fluxes. Utilizing a result of Etingof, Nikshych, and Ostrik, we point out that a class of obstructions is captured by the fourth cohomology group H^{4}(G,U(1, which also precisely labels the set of 3D SPT phases, with symmetry group G. An explicit procedure for calculating the cohomology data from a SET is given, with the corresponding physical intuition explained. We thus establish a general bulk-boundary correspondence between the anomalous SET and the 3D bulk SPT whose surface termination realizes it. We illustrate this idea using the chiral spin liquid [U(1_{2}] topological order with a reduced symmetry Z_{2}×Z_{2}⊂SO(3, which can act on the semion quasiparticle in an anomalous way. We construct exactly solved 3D SPT models realizing the anomalous surface terminations and demonstrate that they are nontrivial by computing three-loop braiding statistics. Possible extensions to antiunitary symmetries are also discussed.
Micro-instabilities and anomalous transport
International Nuclear Information System (INIS)
Connor, J.W.
1992-01-01
In order to optimise the design of a tokamak fusion reactor it is necessary to understand how the energy confinement time depends on the plasma and machine parameters. In principle the neo-classical theory provides this information but empirical evidence yields confinement times up to two orders of magnitude less than the predictions of this model. Experimental evidence of microscopic fluctuations in plasma density and other quantities suggests turbulent electro-magnetic fluctuations may be responsible for this anomalous transport. (Author)
Anomalous hall effect in ferromagnetic semiconductors
Czech Academy of Sciences Publication Activity Database
Jungwirth, Tomáš; Niu, Q.; MacDonald, A. H.
2002-01-01
Roč. 88, č. 20 (2002), s. 207208-1-207208-4 ISSN 0031-9007 R&D Projects: GA ČR GA202/02/0912; GA MŠk OC P5.10 Institutional research plan: CEZ:AV0Z1010914 Keywords : ferromagnetic semiconductors * anomalous Hall effect Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 7.323, year: 2002
Probing anomalous gauge boson couplings at LEP
International Nuclear Information System (INIS)
Dawson, S.; Valencia, G.
1994-01-01
We bound anomalous gauge boson couplings using LEP data for the Z → bar ∫∫ partial widths. We use an effective field theory formalism to compute the one-loop corrections resulting from non-standard model three and four gauge boson vertices. We find that measurements at LEP constrain the three gauge boson couplings at a level comparable to that obtainable at LEPII
Multislice CT imaging of anomalous coronary arteries
International Nuclear Information System (INIS)
Shi Heshui; Aschoff, Andrik J.; Brambs, Hans-Juergen; Hoffmann, Martin H.K.
2004-01-01
The purpose of the present study was to evaluate the role of 16 multislice computed tomography (MSCT) to identify the origin of anomalous coronary arteries and to confirm their anatomic course in relation to the great vessels. Accuracy of coronary artery disease (CAD) detection was a secondary aim and was tested with conventional angiograms (CA) serving as standard of reference. Two hundred and forty-two consecutive patients referred for noninvasive coronary CT imaging were reviewed for the study. Sixteen patients (6.6%) with anomalous coronary arteries were detected and included as the study group. MSCT and CA images were analyzed in a blinded fashion for accuracy of anomalous artery origin and path detection. Results were compared in a secondary consensus evaluation. Accuracy ratios to detect CAD with MSCT in all vessels were calculated. Coronary anomalies for all 16 patients were correctly displayed on MSCT. CA alone achieved correct identification of the abnormality in only 53% (P=0.016). Sensitivity and specificity of MSCT to detect significantly stenosed vessels was 90 and 92%. 16-MSCT is accurate to delineate abnormally branching coronary arteries and allows sufficiently accurate detection of obstructive coronary artery disease in distal branches. It should therefore be considered as a prime non-invasive imaging tool for suspected coronary anomalies. (orig.)
The Anomalous Magnetic Moment of the Muon
Jegerlehner, Friedrich
2008-01-01
This book reviews the present state of knowledge of the anomalous magnetic moment a=(g-2)/2 of the muon. The muon anomalous magnetic moment amy is one of the most precisely measured quantities in elementary particle physics and provides one of the most stringent tests of relativistic quantum field theory as a fundamental theoretical framework. It allows for an extremely precise check of the standard model of elementary particles and of its limitations. Recent experiments at the Brookhaven National Laboratory now reach the unbelievable precision of 0.5 parts per million, improving the accuracy of previous g-2 experiments at CERN by a factor of 14. A major part of the book is devoted to the theory of the anomalous magnetic moment and to estimates of the theoretical uncertainties. Quantum electrodynamics and electroweak and hadronic effects are reviewed. Since non-perturbative hadronic effects play a key role for the precision test, their evaluation is described in detail. After the overview of theory, the exper...
Anomalous dissolution of metals and chemical corrosion
Directory of Open Access Journals (Sweden)
DRAGUTIN M. DRAZIC
2005-03-01
Full Text Available An overview is given of the anomalous behavior of some metals, in particular Fe and Cr, in acidic aqueous solutions during anodic dissolution. The anomaly is recognizable by the fact that during anodic dissolutionmore material dissolves than would be expected from the Faraday law with the use of the expected valence of the formed ions. Mechanical disintegration, gas bubble blocking, hydrogen embrittlement, passive layer cracking and other possible reasons for such behavior have been discussed. It was shown, as suggested by Kolotyrkin and coworkers, that the reason can be, also, the chemical reaction in which H2O molecules with the metal form metal ions and gaseous H2 in a potential independent process. It occurs simultaneously with the electrochemical corrosion process, but the electrochemical process controls the corrosion potential. On the example of Cr in acid solution itwas shown that the reason for the anomalous behavior is dominantly chemical dissolution, which is considerably faster than the electrochemical corrosion, and that the increasing temperature favors chemical reaction, while the other possible reasons for the anomalous behavior are of negligible effect. This effect is much smaller in the case of Fe, but exists. The possible role of the chemical dissolution reacton and hydrogen evolution during pitting of steels and Al and stress corrosion cracking or corrosion fatigue are discussed.
Anomalous effect of high-frequency ultrasound on radiation diffraction in deformed single crystals
International Nuclear Information System (INIS)
Iolin, E.M.; Rajtman, Eh.A.; Kuvaldin, B.V.; Zolotoyabko, Eh.V.
1988-01-01
Results are presented of a theoretical and experimental study of neutron and X-ray diffraction in defromed single crystals on high-frequency ultrasonic excitation. It is demonstrated theoretically that at a frequency exceeding a certain threshold value the ultrasound violates the adiabatic conditions for the excitation point motion on the dispersion surface branches. This leads to an anomalous (compared to diffraction for a perfect crystal) dependence of the diffraction intensity on the ultrasonic wave amplitude. The experimental data for Si crystals are in good agreement with the theoretical predictions
Anomalous electrodynamics of neutral pion matter in strong magnetic fields
Energy Technology Data Exchange (ETDEWEB)
Brauner, Tomáš [Department of Mathematics and Natural Sciences, University of Stavanger,N-4036 Stavanger (Norway); Kadam, Saurabh V. [Indian Institute of Science Education and Research (IISER),Pune 411008 (India)
2017-03-03
The ground state of quantum chromodynamics in sufficiently strong external magnetic fields and at moderate baryon chemical potential is a chiral soliton lattice (CSL) of neutral pions https://arxiv.org/abs/1609.05213. We investigate the interplay between the CSL structure and dynamical electromagnetic fields. Our main result is that in presence of the CSL background, the two physical photon polarizations and the neutral pion mix, giving rise to two gapped excitations and one gapless mode with a nonrelativistic dispersion relation. The nature of this mode depends on the direction of its propagation, interpolating between a circularly polarized electromagnetic wave https://www.doi.org/10.1103/PhysRevD.93.085036 and a neutral pion surface wave, which in turn arises from the spontaneously broken translation invariance. Quite remarkably, there is a neutral-pion-like mode that remains gapped even in the chiral limit, in seeming contradiction to the Goldstone theorem. Finally, we have a first look at the effect of thermal fluctuations of the CSL, showing that even the soft nonrelativistic excitation does not lead to the Landau-Peierls instability. However, it leads to an anomalous contribution to pressure that scales with temperature and magnetic field as T{sup 5/2}(B/f{sub π}){sup 3/2}.
Polaritons dispersion in a composite ferrite-semiconductor structure near gyrotropic-nihility state
International Nuclear Information System (INIS)
Tuz, Vladimir R.
2016-01-01
In the context of polaritons in a ferrite-semiconductor structure which is influenced by an external static magnetic field, the gyrotropic-nihility can be identified from the dispersion equation related to bulk polaritons as a particular extreme state, at which the longitudinal component of the corresponding constitutive tensor and bulk constant simultaneously acquire zero. Near the frequency of the gyrotropic-nihility state, the conditions of branches merging of bulk polaritons, as well as an anomalous dispersion of bulk and surface polaritons are found and discussed. - Highlights: • Gyrotropic-nihility state is identified from the dispersion equation related to bulk polaritons in a magnetic-semiconductor superlattice. • The conditions of branches merging of bulk polaritons are found. • An anomalous dispersion of bulk and surface polaritons is found and discussed.
Polaritons dispersion in a composite ferrite-semiconductor structure near gyrotropic-nihility state
Energy Technology Data Exchange (ETDEWEB)
Tuz, Vladimir R., E-mail: tvr@rian.kharkov.ua
2016-12-01
In the context of polaritons in a ferrite-semiconductor structure which is influenced by an external static magnetic field, the gyrotropic-nihility can be identified from the dispersion equation related to bulk polaritons as a particular extreme state, at which the longitudinal component of the corresponding constitutive tensor and bulk constant simultaneously acquire zero. Near the frequency of the gyrotropic-nihility state, the conditions of branches merging of bulk polaritons, as well as an anomalous dispersion of bulk and surface polaritons are found and discussed. - Highlights: • Gyrotropic-nihility state is identified from the dispersion equation related to bulk polaritons in a magnetic-semiconductor superlattice. • The conditions of branches merging of bulk polaritons are found. • An anomalous dispersion of bulk and surface polaritons is found and discussed.
Patterns and mechanisms of dispersal in a keystone seagrass species
DEFF Research Database (Denmark)
Jahnke, M.; Christensen, Asbjørn; Micu, D.
2016-01-01
•Z. noltei shows low genetic connectivity (from 10 s to 100 s of km) in the Black Sea.•Physical modelling of dispersal well agree with estimates of genetic connectivity.•Physical and genetic connectivity show possible but rare long distance dispersal.•Seeds get dispersed locally while shoots have...
Intrinsic anomalous surface roughening of TiN films deposited by reactive sputtering
International Nuclear Information System (INIS)
Auger, M. A.; Vazquez, L.; Sanchez, O.; Cuerno, R.; Castro, M.; Jergel, M.
2006-01-01
We study surface kinetic roughening of TiN films grown on Si(100) substrates by dc reactive sputtering. The surface morphology of films deposited for different growth times under the same experimental conditions were analyzed by atomic force microscopy. The TiN films exhibit intrinsic anomalous scaling and multiscaling. The film kinetic roughening is characterized by a set of local exponent values α loc =1.0 and β loc =0.39, and global exponent values α=1.7 and β=0.67, with a coarsening exponent of 1/z=0.39. These properties are correlated to the local height-difference distribution function obeying power-law statistics. We associate this intrinsic anomalous scaling with the instability due to nonlocal shadowing effects that take place during thin-film growth by sputtering
Clock synchronization and dispersion
International Nuclear Information System (INIS)
Giovannetti, Vittorio; Lloyd, Seth; Maccone, Lorenzo; Wong, Franco N C
2002-01-01
We present a method to defeat effects of dispersion of timing signals when synchronizing clocks. It is based on the recently proposed 'conveyor belt synchronization' scheme and on the quantum dispersion cancellation effect
Dispersion engineering of thick high-Q silicon nitride ring-resonators via atomic layer deposition.
Riemensberger, Johann; Hartinger, Klaus; Herr, Tobias; Brasch, Victor; Holzwarth, Ronald; Kippenberg, Tobias J
2012-12-03
We demonstrate dispersion engineering of integrated silicon nitride based ring resonators through conformal coating with hafnium dioxide deposited on top of the structures via atomic layer deposition. Both, magnitude and bandwidth of anomalous dispersion can be significantly increased. The results are confirmed by high resolution frequency-comb-assisted-diode-laser spectroscopy and are in very good agreement with the simulated modification of the mode spectrum.
Photon trajectories, anomalous velocities and weak measurements: a classical interpretation
International Nuclear Information System (INIS)
Bliokh, Konstantin Y; Kofman, Abraham G; Nori, Franco; Bekshaev, Aleksandr Y
2013-01-01
Recently, Kocsis et al (2011 Science 332 1170) reported the observation of ‘average trajectories of single photons’ in a two-slit interference experiment. This was possible by using the quantum weak-measurement method, which implies averaging over many events, i.e. in fact, a multi-photon limit of classical linear optics. We give a classical-optics interpretation of this experiment and other related problems. It appears that weak measurements of the local momentum of photons made by Kocsis et al represent measurements of the Poynting vector in an optical field. We consider both the real and imaginary parts of the local momentum and show that their measurements have been realized in classical optics using small-probe particles. We also examine the appearance of ‘anomalous’ values of the local momentum: either negative (backflow) or exceeding the wavenumber (superluminal propagation). These features appear to be closely related to vortices and evanescent waves. Finally, we revisit a number of older works and find examples of photon trajectories and anomalous-momentum measurements in various optical experiments. (paper)
Nelson, RD
1988-01-01
This book provides powder technologists with laboratory procedures for selecting dispersing agents and preparing stable dispersions that can then be used in particle size characterization instruments. Its broader goal is to introduce industrial chemists and engineers to the phenomena, terminology, physical principles, and chemical considerations involved in preparing and handling dispersions on a commercial scale. The book introduces novices to: - industrial problems due to improper degree of dispersion; - the nomenclature used in describing particles; - the basic physica
Anomalous dimensions of spin-zero four-quark operators without derivatives
International Nuclear Information System (INIS)
Jamin, M.; Kremer, M.
1986-01-01
The anomalous dimensions of local spin-zero four-quark operators without derivatives are calculated for the case of three flavours. We also give the result in the approximation that no flavour mixing occurs, because this may be relevant for lattice calculations of four-quark condensates in the quenched approximation. We demonstrate the influence of the operator mixing in a specific example. (orig.)
International Nuclear Information System (INIS)
Qu Wenxiao
1992-01-01
Assuming that there exists a position in the tokamak plasma where the energy transport is dominated by local anomalous electron thermal conduction and taking advantage of the basic experimental result usually referred to as profile consistency, the authors obtain a more convincing approach to the description of the confinement property of tokamak devices without touching upon the physical mechanism of global plasma energy transport. 8 refs
Guo, Zaibing
2015-05-01
The effect of interfacial intermixing on magnetization and anomalous Hall effect (AHE) in Co/Pd multilayers is studied by using rapid thermal annealing to enhance the interfacial diffusion. The dependence of saturation magnetization and coercivity on the temperature of rapid thermal annealing at 5 K is discussed. It is found that AHE is closely related to the relative thickness of the Co and Pd layers. Localized paramagnetism has been observed which destroys AHE, while AHE can be enhanced by annealing.
Contemporary Use of Anomalous Diffraction in Biomolecular Structure Analysis
Energy Technology Data Exchange (ETDEWEB)
Liu Q.; Hendrickson, W.
2017-01-01
The normal elastic X-ray scattering that depends only on electron density can be modulated by an ?anomalous? component due to resonance between X-rays and electronic orbitals. Anomalous scattering thereby precisely identifies atomic species, since orbitals distinguish atomic elements, which enables the multi- and single-wavelength anomalous diffraction (MAD and SAD) methods. SAD now predominates in de novo structure determination of biological macromolecules, and we focus here on the prevailing SAD method. We describe the anomalous phasing theory and the periodic table of phasing elements that are available for SAD experiments, differentiating between those readily accessible for at-resonance experiments and those that can be effective away from an edge. We describe procedures for present-day SAD phasing experiments and we discuss optimization of anomalous signals for challenging applications. We also describe methods for using anomalous signals as molecular markers for tracing and element identification. Emerging developments and perspectives are discussed in brief.
Presentation: 3D magnetic inversion by planting anomalous densities
Uieda, Leonardo; Barbosa, Valeria C. F.
2013-01-01
Slides for the presentation "3D magnetic inversion by planting anomalous densities" given at the 2013 AGU Meeting of the Americas in Cancun, Mexico. Note: There was an error in the title of the talk. The correct title should be "3D magnetic inversion by planting anomalous magnetization" Abstract: We present a new 3D magnetic inversion algorithm based on the computationally efficient method of planting anomalous densities. The algorithm consists of an iterative growth of the an...
Anomalous x-ray radiation of beam plasma
International Nuclear Information System (INIS)
Dimitrov, S.K.; Zavyalov, M.A.; Mikhin, S.G.; Tarasenkov, V.A.; Telkovskij, V.G.; Khrabrov, V.A.
1985-01-01
The properties of non-equilibrium stationary plasma under the conditions of the planned plasma-chemical reactors based on beam-plasma discharge were investigated. The x-ray spectrum of the beam-plasma was measured and anomalous spectral properties were analyzed. Starting with some critical pressure the anomalous radiation was added to the classical bremsstrahlung spectrum. The occurrence of anomalous radiation can be used to diagnose the condition of beam transportation in such systems. (D.Gy.)
Inclusive anomalous muon production in e+e- annihilation
International Nuclear Information System (INIS)
Feldman, G.J.; Bulos, F.; Lueke, D.; Abrams, G.S.; Alam, M.S.; Boyarski, A.M.; Breidenbach, M.; Dorfan, J.; Friedberg, C.E.; Fryberger, D.; Goldhaber, G.; Hanson, G.; Heile, F.B.; Jaros, J.A.; Kadyk, J.A.; Larsen, R.R.; Litke, A.M.; Lueth, V.; Madaras, R.J.; Morehouse, C.C.; Nguyen, H.K.; Paterson, J.M.; Perl, M.L.; Peruzzi, I.; Piccolo, M.; Pierre, F.M.; Pun, T.P.; Rapidis, P.; Richter, B.; Sadoulet, B.; Schwitters, R.F.; Tanenbaum, W.; Trilling, G.H.; Vannucci, F.; Whitaker, J.S.; Wiss, J.E.
1977-01-01
We present measurements of inclusive anomalous muon production in e + e - annihilations in three energy ranges. In all three ranges we observe a large anomalous muon production rate in two-prong events which is compatible with the expected decays of pairs of heavy leptons. In the highest energy range there is also appreciable anomalous muon production in multiprong events which, due to its magnitude and momentum dependence, must come in part from a source other than a heavy lepton
Anomalous Cepheids and population II blue stragglers
Nemec, James M.
Recent studies of anomalous Cepheids (ACs) and population II blue stragglers (BSs), including photometrically variable BSs (VBSs), are reviewed. The VBSs represent about 25 percent of the BSs, the majority of which are SX Phe short-period variables in the Cepheid instability strip. Mass estimates derived using various techniques suggest that both ACs and BSs are relatively massive (about 1.0-1.6 solar mass). The recent discovery that two BSs in the globular cluster NGC 5466 are contact binaries, and the earlier discovery that one of the BSs in Omega Cen is an eclipsing binary, provide direct evidence that at least some BSs are binary systems.
Global constraints on top quark anomalous couplings
Déliot, Frédéric; Faria, Ricardo; Fiolhais, Miguel C. N.; Lagarelhos, Pedro; Onofre, António; Pease, Christopher M.; Vasconcelos, Ana
2018-01-01
The latest results on top quark physics, namely single top quark production cross sections, W -boson helicity and asymmetry measurements are used to probe the Lorentz structure of the W t b vertex. The increase of sensitivity to new anomalous physics contributions to the top quark sector of the standard model is quantified by combining the relevant results from Tevatron and the Large Hadron Collider. The results show that combining an increasing set of available precision measurements in the search for new physics phenomena beyond the standard model leads to significant sensitivity improvements, especially when compared with the current expectation for the High Luminosity run at the LHC.
Observations of anomalous fading in maiolica
International Nuclear Information System (INIS)
Bowman, S.G.E.
1988-01-01
In the course of an authenticity study on Italian maiolica (tin-glazed earthenware of the Renaissance period), storage at elevated temperature was used to accelerate anomalous fading. Substantial levels of fading were observed in about half of the samples, and in these cases the variation of fading with glow curve temperature accounted for the lack of an equivalent dose plateau. Some evidence was found for a difference in the fading between alpha and beta induced thermoluminescence (TL). More importantly, some samples with unstable natural TL were found: the implications of this for dating and the circumvention of fading are discussed. (author)
Anomalous vector-boson self-interactions
International Nuclear Information System (INIS)
Nir, Y.
1988-03-01
We study the possibility that vector-boson self-couplings may differ from their standard model values. We find that known constraints from loop-effects and from unitarity already imply that such deviations are of order 10 -2 or less. Consequently, even if the correct model differs from the standard model and even if the energy scale of new physics is as low as 1 TeV, a direct observation of anomalous couplings is very improbable in the LEP-200 and Tevatron experiments. (author)
The anomalous magnetic moment of the muon
International Nuclear Information System (INIS)
Farley, F.J.M.
1975-01-01
A historical survey of the measurements of the gyromagnetic ratio g of the muon. A brief introduction is given to the theory of the 'anomalous magnetic moment' a equivalent to 1/2(g-2) and its significance is explained. The main part of the review concerns the successive (g-2) experiments to measure a directly, with gradually increasing accuracy. At present experiment and theory agree to (13+-29) parts in 10 9 in g, and the muon still obeys the rules of quantum electrodynamics for a structureless point charge. (author)
DEFF Research Database (Denmark)
Frosz, Michael Henoch; Falk, Peter Andreas; Bang, Ole
2005-01-01
Supercontinuum generation with femtosecond pulses in photonic crystal fibers with two zero-dispersion wavelengths (ZDWs) is investigated numerically. The role of the higher ZDW is examined for 5 fiber designs with a nearly constant lower ZDW. It is found that the resulting spectrum is mainly....... Further, the generation of a bright-bright soliton-pair from an initial single red-shifted soliton is found. The soliton-pair has one color in the anomalous dispersion region and the other color in the normal dispersion region, which has not previously been described for bright-bright soliton-pairs....
Theory of dispersive microlenses
Herman, B.; Gal, George
1993-01-01
A dispersive microlens is a miniature optical element which simultaneously focuses and disperses light. Arrays of dispersive mircolenses have potential applications in multicolor focal planes. They have a 100 percent optical fill factor and can focus light down to detectors of diffraction spot size, freeing up areas on the focal plane for on-chip analog signal processing. Use of dispersive microlenses allows inband color separation within a pixel and perfect scene registration. A dual-color separation has the potential for temperature discrimination. We discuss the design of dispersive microlenses and present sample results for efficient designs.
Solitonic Dispersive Hydrodynamics: Theory and Observation
Maiden, Michelle D.; Anderson, Dalton V.; Franco, Nevil A.; El, Gennady A.; Hoefer, Mark A.
2018-04-01
Ubiquitous nonlinear waves in dispersive media include localized solitons and extended hydrodynamic states such as dispersive shock waves. Despite their physical prominence and the development of thorough theoretical and experimental investigations of each separately, experiments and a unified theory of solitons and dispersive hydrodynamics are lacking. Here, a general soliton-mean field theory is introduced and used to describe the propagation of solitons in macroscopic hydrodynamic flows. Two universal adiabatic invariants of motion are identified that predict trapping or transmission of solitons by hydrodynamic states. The result of solitons incident upon smooth expansion waves or compressive, rapidly oscillating dispersive shock waves is the same, an effect termed hydrodynamic reciprocity. Experiments on viscous fluid conduits quantitatively confirm the soliton-mean field theory with broader implications for nonlinear optics, superfluids, geophysical fluids, and other dispersive hydrodynamic media.
Zγ production at NNLO including anomalous couplings
Campbell, John M.; Neumann, Tobias; Williams, Ciaran
2017-11-01
In this paper we present a next-to-next-to-leading order (NNLO) QCD calculation of the processes pp → l + l -γ and pp\\to ν \\overline{ν}γ that we have implemented in MCFM. Our calculation includes QCD corrections at NNLO both for the Standard Model (SM) and additionally in the presence of Zγγ and ZZγ anomalous couplings. We compare our implementation, obtained using the jettiness slicing approach, with a previous SM calculation and find broad agreement. Focusing on the sensitivity of our results to the slicing parameter, we show that using our setup we are able to compute NNLO cross sections with numerical uncertainties of about 0.1%, which is small compared to residual scale uncertainties of a few percent. We study potential improvements using two different jettiness definitions and the inclusion of power corrections. At √{s}=13 TeV we present phenomenological results and consider Zγ as a background to H → Zγ production. We find that, with typical cuts, the inclusion of NNLO corrections represents a small effect and loosens the extraction of limits on anomalous couplings by about 10%.
Anomalous Stars and Where to Find Them
Muna, Demitri; Huff, Eric
2018-01-01
The sky is now extensively mapped by imaging surveys in wavelengths that span the electromagnetic spectrum, ranging from Fermi and GALEX down to WISE, Planck, and radio surveys like FIRST and VLSS. Individual public catalogs now contain on order hundreds of millions of distinct sources. Recent progress in image analysis techniques makes possible great increases in the efficiency, sensitivity, and reliability of measurements that combine imaging data from multiple probes with heterogeneous properties. This is especially true for the identification of anomalous sources: traditional methods for finding ‘outliers’ typically rely on making hard cuts on noisy catalog properties, greatly restricting the potential discovery space. Cross-catalog matches confine investigation to objects that occur at signal-to-noise ratios sufficient to be independently detectable in a subset of all the available multi-wavelength coverage. The process of merging the latest analyses with existing data is severely hampered, however, by the fractured way in which these data are processed and stored, limitations of data access, the data volume involved, and the computation power required. This has left archive data far from fully exploited. Stellar anomalies present the best place to start: joint distributions of stellar colors and magnitudes have finer structures than extended sources, and modelling of point sources is computationally cheaper than for galaxies. We present a framework to solve the problem of applying new algorithms to old data while overcoming the limitations described above, in the search for the undiscovered anomalous.
Unparticles and anomalous dimensions in the cuprates
Energy Technology Data Exchange (ETDEWEB)
Karch, Andreas [Department of Physics, University of Washington,3910 15th Ave. NE, Seattle, WA 98195-1560 (United States); Limtragool, Kridsanaphong; Phillips, Philip W. [Department of Physics and Institute for Condensed Matter Theory, University of Illinois,1110 W. Green Street, Urbana, IL 61801 (United States)
2016-03-25
Motivated by the overwhelming evidence some type of quantum criticality underlies the power-law for the optical conductivity and T−linear resistivity in the cuprates, we demonstrate here how a scale-invariant or unparticle sector can lead to a unifying description of the observed scaling forms. We adopt the continuous mass formalism or multi band (flavor) formalism of the unparticle sector by letting various microscopic parameters be mass-dependent. In particular, we show that an effective mass that varies with the flavor index as well as a running band edge and lifetime capture the AC and DC transport phenomenology of the cuprates. A key consequence of the running mass is that the effective dynamical exponent can differ from the underlying bare critical exponent, thereby providing a mechanism for realizing the fractional values of the dynamical exponent required in a previous analysis http://dx.doi.org/10.1103/PhysRevB.91.155126. We also predict that regardless of the bare dynamical exponent, z, a non-zero anomalous dimension for the current is required. Physically, the anomalous dimension arises because the charge depends on the flavor, mass or energy. The equivalent phenomenon in a d+1 gravitational construction is the running of the charge along the radial direction. The nature of the superconducting instability in the presence of scale invariant stuff shows that the transition temperature is not necessarily a monotonic function of the pairing interaction.
More modular invariant anomalous U(1) breaking
International Nuclear Information System (INIS)
Gaillard, Mary K.; Giedt, Joel
2002-01-01
We consider the case of several scalar fields, charged under a number of U(1) factors, acquiring vacuum expectation values due to an anomalous U(1). We demonstrate how to make redefinitions at the superfield level in order to account for tree-level exchange of vector supermultiplets in the effective supergravity theory of the light fields in the supersymmetric vacuum phase. Our approach builds upon previous results that we obtained in a more elementary case. We find that the modular weights of light fields are typically shifted from their original values, allowing an interpretation in terms of the preservation of modular invariance in the effective theory. We address various subtleties in defining unitary gauge that are associated with the noncanonical Kaehler potential of modular invariant supergravity, the vacuum degeneracy, and the role of the dilaton field. We discuss the effective superpotential for the light fields and note how proton decay operators may be obtained when the heavy fields are integrated out of the theory at the tree-level. We also address how our formalism may be extended to describe the generalized Green-Schwarz mechanism for multiple anomalous U(1)'s that occur in four-dimensional Type I and Type IIB string constructions
Elucidation of the mechanism for anomalous blueshift
International Nuclear Information System (INIS)
Kotaki, Hideyuki; Kando, Masaki; Koga, J.K.; Nakajima, Kazuhisa
2004-01-01
The anomalous blue shift of high intensity laser which was discovered by the present authors occurs in the process of gas ionization accompanied with the self-focusing. This shift does not depend either on the laser power or on the gas density and all photons are shifted by a certain frequency, while the one which has been known in common depends on both the intensity and density and only some part of the laser photons is shifted. In order to elucidate this phenomenon, the occurrence conditions of the anomalous blue shift were investigated and the results are compared with theory. The shifts were measured by focusing the laser beam in the gas-filled chamber with an off-axis-parabolic mirror and with a convex lens. When the reflective lens was used the amount of the shift depended significantly on the ionization rate of the plasma, while it depended on the pulse width when the transmission lens was used indicating that the shift is determined by the valence due to the ionization at the focusing point. (S. Funahashi)
Anomalous Micellization of Pluronic Block Copolymers
Leonardi, Amanda; Ryu, Chang Y.
2014-03-01
Poly(ethylene oxide) - poly(propylene oxide) - poly(ethylene oxide) (PEO-PPO-PEO) block copolymers, commercially known as Pluronics, are a unique family of amphiphilic triblock polymers, which self-assemble into micelles in aqueous solution. These copolymers have shown promise in therapeutic, biomedical, cosmetic, and nanotech applications. As-received samples of Pluronics contain low molecular weight impurities (introduced during the manufacturing and processing), that are ignored in most applications. It has been observed, however, that in semi-dilute aqueous solutions, at concentrations above 1 wt%, the temperature dependent micellization behavior of the Pluronics is altered. Anomalous behavior includes a shift of the critical micellization temperature and formation of large aggregates at intermediate temperatures before stable sized micelles form. We attribute this behavior to the low molecular weight impurities that are inherent to the Pluronics which interfere with the micellization process. Through the use of Dynamic Light Scattering and HPLC, we compared the anomalous behavior of different Pluronics of different impurity levels to their purified counterparts.
Anomalous growth of Ba on Ag(111)
International Nuclear Information System (INIS)
Teodoro, O.M.N.D.; Los, J.; Moutinho, A.M.C.
2002-01-01
Electropositive elements are often adsorbed on metals to produce a well-known decrease in the surface work function. During deposition, the work function drops steeply and reaches a minimum at coverage lower than one monolayer. Then, it increases slightly and the work function converges to the value of the deposited element. In this work, we report anomalous behavior found during the deposition of barium on a Ag(111) surface. After a minimum of about 2.4 eV the work function did not increase up to 2.7 eV, the bulk barium work function, no matter what amount of barium was deposited. Auger electron spectroscopy corroborated these results in which we measured a permanent and constant intensity of the Ag MNN peak for high barium coverage. To explain this anomalous growth of barium on Ag(111) we propose an explanation based on the diffusion of silver atoms into the barium film. Further experiments showed that coadsorption of oxygen before a second deposition of barium blocked the diffusion thus allowing the work function to reach 2.7 eV
Anomalous vibrational properties in the continuum limit of glasses
Shimada, Masanari; Mizuno, Hideyuki; Ikeda, Atsushi
2018-02-01
The low-temperature thermal properties of glasses are anomalous with respect to those of crystals. These thermal anomalies indicate that the low-frequency vibrational properties of glasses differ from those of crystals. Recent studies revealed that, in the simplest model of glasses, i.e., the harmonic potential system, phonon modes coexist with soft localized modes in the low-frequency (continuum) limit. However, the nature of low-frequency vibrational modes of more realistic models is still controversial. In the present work, we study the Lennard-Jones (LJ) system using large-scale molecular-dynamics (MD) simulation and establish that the vibrational property of the LJ glass converges to coexistence of the phonon modes and the soft localized modes in the continuum limit as in the case of the harmonic potential system. Importantly, we find that the low-frequency vibrations are rather sensitive to the numerical scheme of potential truncation, which is usually implemented in the MD simulation, and this is the reason why contradictory arguments have been reported by previous works. We also discuss the physical origin of this sensitiveness by means of a linear stability analysis.
Chaotic Lagrangian models for turbulent relative dispersion.
Lacorata, Guglielmo; Vulpiani, Angelo
2017-04-01
A deterministic multiscale dynamical system is introduced and discussed as a prototype model for relative dispersion in stationary, homogeneous, and isotropic turbulence. Unlike stochastic diffusion models, here trajectory transport and mixing properties are entirely controlled by Lagrangian chaos. The anomalous "sweeping effect," a known drawback common to kinematic simulations, is removed through the use of quasi-Lagrangian coordinates. Lagrangian dispersion statistics of the model are accurately analyzed by computing the finite-scale Lyapunov exponent (FSLE), which is the optimal measure of the scaling properties of dispersion. FSLE scaling exponents provide a severe test to decide whether model simulations are in agreement with theoretical expectations and/or observation. The results of our numerical experiments cover a wide range of "Reynolds numbers" and show that chaotic deterministic flows can be very efficient, and numerically low-cost, models of turbulent trajectories in stationary, homogeneous, and isotropic conditions. The mathematics of the model is relatively simple, and, in a geophysical context, potential applications may regard small-scale parametrization issues in general circulation models, mixed layer, and/or boundary layer turbulence models as well as Lagrangian predictability studies.
Contribution of MRI in supracardiac total anomalous pulmonary venous drainage
International Nuclear Information System (INIS)
Kastler, B.; Germain, P.; Gangi, A.; Klinkert, A.; Dietemann, J.L.; Wackenheim, A.; Livolsi, A.; Willard, D.
1992-01-01
A case of supracardiac total anomalous pulmonary venous drainage (TAPVD) in an infant aged 2 1/2 months is presented. Diagnosis was established non invasively by magnetic resonance image (MRI). Not only did MRI precisely depict the anomalous venous pathway but it moreover securely excluded pulmonary venous obstruction. (orig.)
Nonlinear trapped electron mode and anomalous heat transport in tokamaks
International Nuclear Information System (INIS)
Kaw, P.K.
1982-01-01
We take the phenomenological point of view that the anomalous electron thermal conductivity produced by the non-linear trapped electron mode should also influence the stability properties of the mode itself. Using a model equation, we show that this effect makes the mode self-stabilizing. A simple expression for the anomalous thermal conductivity is derived, and its scaling properties are discussed. (orig.)
Anomalous structural changes and elastic properties of bismuth oxide superconductors
International Nuclear Information System (INIS)
He, Y.S.; Xiang, J.; Chang, F.G.; Zhang, J.C.; He, A.S.; Wang, H.; Gu, B.L.
1989-01-01
Ultrasonic measurement revealed that there are anomalous structural changes near 200 K in single 2212 or 2223 phase samples of Bi(Pb)-Sr-Ca-Cu-O. Detailed study showed such anomalous changes are isothermal-like processes and have a characteristics of second order phase transition, accompanying with increases in lattice constants. The elastic properties of these ceramics and related systems are discussed
Comment on anomalous dispersion and scattering rates for multiphonon spontaneous decay in He II
Haavasoja, T.; Narayanamurti, V.; Chin, M. A.
1984-10-01
We report on new measurements of the spontaneous decay threshold energy E c for high-frequency phonon propagation in He II at saturated vapor pressure at T=0.1 K. Superconducting tin tunnel generators and aluminum tunnel detectors were used in this study. The measurements show that the mean free path becomes much larger than the propagation length of 1.1 mm for a value of E c =9.8±0.15 K. This agrees with the value originally reported ( E c =9.5±0.4 K) by Dynes and Narayanamurti using aluminum tunnel generators, but is shown to correspond to the point where the phase velocity equals the sound velocity, when the phonons become stable, as first proposed by Pitayevski and Levinson. Evidence for n-phonon decay at energies lower than E c is presented for n≳2 with a short mean free path (neutron data due to Donnelly, Donnelly, and Hills.
Anomalous or regular capacitance? The influence of pore size dispersity on double-layer formation
Jäckel, N.; Rodner, M.; Schreiber, A.; Jeongwook, J.; Zeiger, M.; Aslan, M.; Weingarth, D.; Presser, V.
2016-09-01
The energy storage mechanism of electric double-layer capacitors is governed by ion electrosorption at the electrode surface. This process requires high surface area electrodes, typically highly porous carbons. In common organic electrolytes, bare ion sizes are below one nanometer but they are larger when we consider their solvation shell. In contrast, ionic liquid electrolytes are free of solvent molecules, but cation-anion coordination requires special consideration. By matching pore size and ion size, two seemingly conflicting views have emerged: either an increase in specific capacitance with smaller pore size or a constant capacitance contribution of all micro- and mesopores. In our work, we revisit this issue by using a comprehensive set of electrochemical data and a pore size incremental analysis to identify the influence of certain ranges in the pore size distribution to the ion electrosorption capacity. We see a difference in solvation of ions in organic electrolytes depending on the applied voltage and a cation-anion interaction of ionic liquids in nanometer sized pores.
International Nuclear Information System (INIS)
Baziljevich, M.; Johansen, T.H.; Bratsberg, H.; Shen, Y.; Vase, P.
1996-01-01
Slits patterned into a YBa 2 Cu 3 O 7-δ thin film were observed to obstruct Meissner sheet currents leading to an imbalance in the local Meissner screening properties. The new phenomenon was studied with magneto-optic imaging where twin lobes of opposite flux polarity were seen to form near the slits and inside the Meissner region. The lobe closest to the sample edge is always polarized opposite to the applied field. At weak fields, the anomalous flux generation is reversible. At higher fields, but still sufficiently small to keep the vortex penetration front away from the slits, the anomalous current starts nucleating flux lines which become trapped when the field is removed. copyright 1996 American Institute of Physics
The anomalous dimension of the gluon-ghost mass operator in Yang-Mills theory
International Nuclear Information System (INIS)
Dudal, D.; Verschelde, H.; Lemes, V.E.R.; Sarandy, M.S.; Sobreiro, R.; Sorella, S.P.; Picariello, M.; Gracey, J.A.
2003-01-01
The local composite gluon-ghost operator (((1)/(2))A aμ A μ a +αc-bar a c a ) is analysed in the framework of the algebraic renormalization in SU(N) Yang-Mills theories in the Landau, Curci-Ferrari and maximal abelian gauges. We show, to all orders of perturbation theory, that this operator is multiplicatively renormalizable. Furthermore, its anomalous dimension is not an independent parameter of the theory, being given by a general expression valid in all these gauges. We also verify the relations we obtain for the operator anomalous dimensions by explicit 3-loop calculations in the MS-bar scheme for the Curci-Ferrari gauge
International Nuclear Information System (INIS)
Macdonald, J Ross
2005-01-01
Analysis by D L Sidebottom of the dispersive frequency response of the real-part of the conductivity, σ'(ω), for many alkali phosphate and metaphosphate glasses, using a fitting model involving a 'universal dynamic response' power law with an exponent n and a constant-loss term, led to anomalous n behaviour that he explained as arising from variable constriction of the local cation conduction space. In order to obtain adequate fits, he eliminated from the data all low-frequency decreases of σ'(ω) below the dc plateau, ones actually associated with electrode effects. Such a cut-off does not, however, eliminate electrode effects possibly present in the high-frequency part of the data range. The results of the present detailed analysis and fitting of both synthetic data and several of his experimental data sets show unequivocally that his anomalous n behaviour arose from neglecting electrode effects. Their inclusion, with or without data cut-off in the fitting model, leads to the expected high-frequency slope value of n = 2/3 associated with bulk conduction, as required by recently published topological effective-dimension considerations for dielectric relaxation in conductive systems. Further, the effects of the inclusion in a full fitting model of series and possibly parallel complex constant-phase-element contributions, representing electrode and nearly constant loss effects, respectively, have been investigated in detail. Such composite models usually lead to best fitting of either the full or cut-off complex data when they include the semi-universal, topologically based K1 bulk model, one indirectly derived from the assumption of stretched-exponential temporal behaviour
Anomalous water absorption in porous materials
Lockington, D A
2003-01-01
The absorption of fluid by unsaturated, rigid porous materials may be characterized by the sorptivity. This is a simple parameter to determine and is increasingly being used as a measure of a material's resistance to exposure to fluids (especially moisture and reactive solutes) in aggressive environments. The complete isothermal absorption process is described by a nonlinear diffusion equation, with the hydraulic diffusivity being a strongly nonlinear function of the degree of saturation of the material. This diffusivity can be estimated from the sorptivity test. In a typical test the cumulative absorption is proportional to the square root of time. However, a number of researchers have observed deviation from this behaviour when the infiltrating fluid is water and there is some potential for chemo-mechanical interaction with the material. In that case the current interpretation of the test and estimation of the hydraulic diffusivity is no longer appropriate. Kuentz and Lavallee (2001) discuss the anomalous b...
Rooted triple consensus and anomalous gene trees
Directory of Open Access Journals (Sweden)
Schmidt Heiko A
2008-04-01
Full Text Available Abstract Background Anomalous gene trees (AGTs are gene trees with a topology different from a species tree that are more probable to observe than congruent gene trees. In this paper we propose a rooted triple approach to finding the correct species tree in the presence of AGTs. Results Based on simulated data we show that our method outperforms the extended majority rule consensus strategy, while still resolving the species tree. Applying both methods to a metazoan data set of 216 genes, we tested whether AGTs substantially interfere with the reconstruction of the metazoan phylogeny. Conclusion Evidence of AGTs was not found in this data set, suggesting that erroneously reconstructed gene trees are the most significant challenge in the reconstruction of phylogenetic relationships among species with current data. The new method does however rule out the erroneous reconstruction of deep or poorly resolved splits in the presence of lineage sorting.
44th Annual Anomalous Absorption Conference
Energy Technology Data Exchange (ETDEWEB)
Beg, Farhat
2014-03-03
Conference Grant Report July 14, 2015 Submitted to the U. S. Department of Energy Attn: Dr. Sean Finnegan By the University of California, San Diego 9500 Gilman Drive La Jolla, California 92093 On behalf of the 44th Annual Anomalous Absorption Conference 8-13 June 2014, in Estes Park, Colorado Support Requested: $10,100 Amount expended: $3,216.14 Performance Period: 1 March 20 14 to 28 February 20 15 Principal Investigator Dr. Farhat Beg Center for Energy Research University of California, San Diego 9500 Gilman Drive La Jolla, California 92093-0417 858-822-1266 (telephone) 858-534-4543 (fax) fbeg@ucsd.edu Administrative Point of Contact: Brandi Pate, 858-534-0851, blpate®ucsd.edu I. Background The forty-fourth Anomalous Absorption Conference was held in Estes Park, Colorado from June 5-8, 2014 (aac2014.ucsd.edu). The first Anomalous Absorption Conference was held in 1971 to assemble experts in the poorly understood area of laser-plasma absorption. The goal of that conference was to address the anomalously large laser absorption seen in plasma experiments with respect to the laser absorption predicted by linear plasma theory. Great progress in this research area has been made in the decades since that first meeting, due in part to the scientific interactions that have occurred annually at this conference. Specifically, this includes the development of nonlinear laser-plasma theory and the simulation of laser interactions with plasmas. Each summer since that first meeting, this week-long conference has been held at unique locations in North America as a scientific forum for intense scientific exchanges relevant to the interaction of laser radiation with plasmas. Responsibility for organizing the conference has traditional rotated each year between the major Inertial Confinement Fusion (ICF) laboratories and universities including LANL, LLNL, LLE, UCLA UC Davis and NRL. As the conference has matured over the past four decades, its technical footprint has expanded
Anomalous photon-assisted tunneling in graphene
International Nuclear Information System (INIS)
Iurov, Andrii; Gumbs, Godfrey; Roslyak, Oleksiy; Huang, Danhong
2012-01-01
We investigated the transmission of Dirac electrons through a potential barrier in the presence of circularly polarized light. An anomalous photon-assisted enhanced transmission is predicted and explained. It is demonstrated that the perfect transmission for nearly head-on collision in infinite graphene is suppressed in gapped dressed states of electrons, which is further accompanied by a shift of peaks as a function of the incident angle away from head-on collision. In addition, the perfect transmission is partially suppressed by a photon-induced gap in illuminated graphene. After the effect of rough edges of the potential barrier or impurity scattering is included, the perfect transmission with no potential barrier becomes completely suppressed and the energy range for the photon-assisted transmission is reduced at the same time. (paper)
Anomalous krypton in the Allende meteorite
Frick, U.
1977-01-01
The reported investigation provides important new data for the heavy noble gases, especially Kr, in the Allende meteorite. The data are used to criticize the original model of Lewis et al. (1975) based on the noble gas data of these researchers. The conclusions reached in the investigation support alternative models which have been mainly based on Xe data by Lewis et al. (1975, 1977). Because of the relatively high noble gas abundances in the separates studied, disturbance from nuclear effects occurring in situ such as spallation and neutron capture is insignificant, offering an opportunity to study primordial Ar, Kr, and Xe. The isotopic and abundance data obtained from the samples largely confirm the noble gas results of Lewis et al. (1975, 1977) where isotopic correlations agree with the correlations of the considered samples. It is found that both Kr and Xe data are consistent with a two component mixture of 'ordinary' as well as 'anomalous' planetary gases.
Anomalous Abelian symmetry in the standard model
International Nuclear Information System (INIS)
Ramond, P.
1995-01-01
The observed hierarchy of quark and lepton masses can be parametrized by nonrenormalizable operators with dimensions determined by an anomalous Abelian family symmetry, a gauge extension to the minimal supersymmetric standard model. Such an Abelian symmetry is generic to compactified superstring theories, with its anomalies compensated by the Green-Schwarz mechanism. If we assume these two symmetries to be the same, we find the electroweak mixing angle to be sin 2 θ ω = 3/8 at the string scale, just by setting the ratio of the product of down quark to charged lepton masses equal to one at the string scale. This assumes no GUT structure. The generality of the result suggests a superstring origin for the standard model. We generalize our analysis to massive neutrinos, and mixings in the lepton sector
Edge separation using diffraction anomalous fine structure
International Nuclear Information System (INIS)
Ravel, B.; Bouldin, C.E.; Renevier, H.; Hodeau, J.L.; Berar, J.F.
1999-01-01
We exploit the crystallographic sensitivity of the Diffraction Anomalous Fine-Structure (DAFS) measurement to separate the fine structure contributions of different atomic species with closely spaced resonant energies. In BaTiO 3 the Ti K edge and Ba Lm edges are separated by 281 eV, or about 8.2 Angstrom -1 ), thus severely limiting the information content of the Ti K edge signal. Using the site selectivity of DAFS we can separate the two fine structure spectra using an iterative Kramers-Kronig method, thus extending the range of the Ti K edge spectrum. This technique has application to many rare earth/transition metal compounds, including many magnetic materials of technological significance for which K and L edges overlap in energy. (au)
Anomalous resistivity in the plasma opening switch
Energy Technology Data Exchange (ETDEWEB)
Dolgachev, G I; Zakatov, L P; Kalinin, Yu G; Kingsep, A S; Nitishinskij, M S; Ushakov, A G [Kurchatov Institute, Moscow (Russian Federation). Applied Physics Division
1997-12-31
Experimental studies and modelling together with analytical considerations of anomalous resistivity in the plasma opening switch (POS) are being pursued to improve the understanding of the physical mechanism of the POS conduction phase. Experiments have been undertaken for a `microsecond` POS of coaxial geometry. Measurements of Stark broadening of the H{sub {alpha}} line allowed turbulent oscillations in plasma to be found at the conductivity stage. A comparison with the modelling including low-frequency (ion-acoustic) turbulence and Doppler broadening (neutral gas temperature 1-3 eV) the electric field value to be estimated to 10-30 kV/cm. The turbulent field increased toward the cathode up to 50 kV/cm in the near-cathode layer. (author). 3 figs., 14 refs.
Case report 376: Accessory (anomalous) soleus muscle
International Nuclear Information System (INIS)
Apple, J.S.; Khoury, M.B.; Martinez, S.; Nunley, J.A.
1986-01-01
In summary, a case has been presented of a 24-year-old woman who developed pain in the left lower extremity while jogging. Physical examination showed a soft, palpable mass medial and anterior to the Achilles tendon in the left lower extremity. Although a lipoma was suspected, plain films and CT studies indicated clearly that the mass was not of fatty density. In fact, the density of the mass was equivalent to adjacent muscles. The mass itself was lying in the soft tissues of the left ankle tissue. An open biopsy showed a normal muscle which represented an accessory soleus muscle - a muscle known to be anomalous on accoasion and reported as being symptomatic or asymptomatic in different individuals. (orig./SHA)
Anomalous normal mode oscillations in semiconductor microcavities
Energy Technology Data Exchange (ETDEWEB)
Wang, H. [Univ. of Oregon, Eugene, OR (United States). Dept. of Physics; Hou, H.Q.; Hammons, B.E. [Sandia National Labs., Albuquerque, NM (United States)
1997-04-01
Semiconductor microcavities as a composite exciton-cavity system can be characterized by two normal modes. Under an impulsive excitation by a short laser pulse, optical polarizations associated with the two normal modes have a {pi} phase difference. The total induced optical polarization is then expected to exhibit a sin{sup 2}({Omega}t)-like oscillation where 2{Omega} is the normal mode splitting, reflecting a coherent energy exchange between the exciton and cavity. In this paper the authors present experimental studies of normal mode oscillations using three-pulse transient four wave mixing (FWM). The result reveals surprisingly that when the cavity is tuned far below the exciton resonance, normal mode oscillation in the polarization is cos{sup 2}({Omega}t)-like, in contrast to what is expected form the simple normal mode model. This anomalous normal mode oscillation reflects the important role of virtual excitation of electronic states in semiconductor microcavities.
Comparison of the anomalous and non-anomalous generalized Schwinger models via functional formalism
International Nuclear Information System (INIS)
Souza Dutra, A. de.
1992-01-01
The Green functions of the two versions of the two versions of the generalized Schwinger model, the anomalous and the non-anomalous one, in their higher order Lagrangian density form are calculated. Furthermore it is shown through a sequence of transformations that the bosonized Lagrangian density is equivalent to the former, at least for the bosonic correlation functions. The introduction of the sources from the beginning, leading to a gauge-invariant source term is also considered. It is verified that the two models have the same correlation functions only of the gauge-invariant sector is taken into account. Finally it is presented a generalization of the Wess-Zumino term, and its physical consequences are studied, in particular the appearance of gauge-dependent massive excitations. (author)
Control of dynamical localization
International Nuclear Information System (INIS)
Gong Jiangbin; Woerner, Hans Jakob; Brumer, Paul
2003-01-01
Control over the quantum dynamics of chaotic kicked rotor systems is demonstrated. Specifically, control over a number of quantum coherent phenomena is achieved by a simple modification of the kicking field. These include the enhancement of the dynamical localization length, the introduction of classical anomalous diffusion assisted control for systems far from the semiclassical regime, and the observation of a variety of strongly nonexponential line shapes for dynamical localization. The results provide excellent examples of controlled quantum dynamics in a system that is classically chaotic and offer opportunities to explore quantum fluctuations and correlations in quantum chaos
No need to replace an "anomalous" primate (Primates) with an "anomalous" bear (Carnivora, Ursidae).
Gutiérrez, Eliécer E; Pine, Ronald H
2015-01-01
By means of mitochondrial 12S rRNA sequencing of putative "yeti", "bigfoot", and other "anomalous primate" hair samples, a recent study concluded that two samples, presented as from the Himalayas, do not belong to an "anomalous primate", but to an unknown, anomalous type of ursid. That is, that they match 12S rRNA sequences of a fossil Polar Bear (Ursusmaritimus), but neither of modern Polar Bears, nor of Brown Bears (Ursusarctos), the closest relative of Polar Bears, and one that occurs today in the Himalayas. We have undertaken direct comparison of sequences; replication of the original comparative study; inference of phylogenetic relationships of the two samples with respect to those from all extant species of Ursidae (except for the Giant Panda, Ailuropodamelanoleuca) and two extinct Pleistocene species; and application of a non-tree-based population aggregation approach for species diagnosis and identification. Our results demonstrate that the very short fragment of the 12S rRNA gene sequenced by Sykes et al. is not sufficiently informative to support the hypotheses provided by these authors with respect to the taxonomic identity of the individuals from which these sequences were obtained. We have concluded that there is no reason to believe that the two samples came from anything other than Brown Bears. These analyses afforded an opportunity to test the monophyly of morphologically defined species and to comment on both their phylogenetic relationships and future efforts necessary to advance our understanding of ursid systematics.
Mcmanus, M. L.
1979-01-01
Dispersal flights of selected species of forest insects which are associated with periodic outbreaks of pests that occur over large contiguous forested areas are discussed. Gypsy moths, spruce budworms, and forest tent caterpillars were studied for their massive migrations in forested areas. Results indicate that large dispersals into forested areas are due to the females, except in the case of the gypsy moth.
Improved new generation dispersants
International Nuclear Information System (INIS)
Anon.
1993-01-01
The use of dispersants to combat oil spills has attracted controversy over the years, and there has been a number of accusations of the chemicals involved doing more harm than good. A new study by the International Petroleum Industry Environmental Conservation Association discusses the positive and the negatives of dispersant use to be considered when drawing up spill contingency plans. (author)
Middleton, B.; Van Diggelen, R.; Jensen, K.
2006-01-01
Question: How does seed dispersal reduce fen isolation and contribute to biodiversity? Location: European and North American fens. Methods: This paper reviews the literature on seed dispersal to fens. Results: Landscape fragmentation may reduce dispersal opportunities thereby isolating fens and reducing genetic exchange. Species in fragmented wetlands may have lower reproductive success, which can lead to biodiversity loss. While fens may have always been relatively isolated from each other, they have become increasingly fragmented in modern times within agricultural and urban landscapes in both Europe and North America. Dispersal by water, animals and wind has been hampered by changes related to development in landscapes surrounding fens. Because the seeds of certain species are long-lived in the seed bank, frequent episodes of dispersal are not always necessary to maintain the biodiversity of fens. However, of particular concern to restoration is that some dominant species, such as the tussock sedge Carex stricta, may not disperse readily between fens. Conclusions: Knowledge of seed dispersal can be used to maintain and restore the biodiversity of fens in fragmented landscapes. Given that development has fragmented landscapes and that this situation is not likely to change, the dispersal of seeds might be enhanced by moving hay or cattle from fens to damaged sites, or by reestablishing lost hydrological connections. ?? IAVS; Opulus Press.
A nonlocal inhomogeneous dispersal process
Cortázar, C.; Coville, J.; Elgueta, M.; Martínez, S.
This article in devoted to the study of the nonlocal dispersal equation u(x,t)=∫R J({x-y}/{g(y)}){u(y,t)}/{g(y)} dy-u(x,t) in R×[0,∞), and its stationary counterpart. We prove global existence for the initial value problem, and under suitable hypothesis on g and J, we prove that positive bounded stationary solutions exist. We also analyze the asymptotic behavior of the finite mass solutions as t→∞, showing that they converge locally to zero.
Arismendi, Ivan; Johnson, Sherri L.; Dunham, Jason B.
2015-01-01
Statistics of central tendency and dispersion may not capture relevant or desired characteristics of the distribution of continuous phenomena and, thus, they may not adequately describe temporal patterns of change. Here, we present two methodological approaches that can help to identify temporal changes in environmental regimes. First, we use higher-order statistical moments (skewness and kurtosis) to examine potential changes of empirical distributions at decadal extents. Second, we adapt a statistical procedure combining a non-metric multidimensional scaling technique and higher density region plots to detect potentially anomalous years. We illustrate the use of these approaches by examining long-term stream temperature data from minimally and highly human-influenced streams. In particular, we contrast predictions about thermal regime responses to changing climates and human-related water uses. Using these methods, we effectively diagnose years with unusual thermal variability and patterns in variability through time, as well as spatial variability linked to regional and local factors that influence stream temperature. Our findings highlight the complexity of responses of thermal regimes of streams and reveal their differential vulnerability to climate warming and human-related water uses. The two approaches presented here can be applied with a variety of other continuous phenomena to address historical changes, extreme events, and their associated ecological responses.
Zhang, Yong; Green, Christopher T.; Tick, Geoffrey R.
2015-01-01
This study evaluates the role of the Peclet number as affected by molecular diffusion in transient anomalous transport, which is one of the major knowledge gaps in anomalous transport, by combining Monte Carlo simulations and stochastic model analysis. Two alluvial settings containing either short- or long-connected hydrofacies are generated and used as media for flow and transport modeling. Numerical experiments show that 1) the Peclet number affects both the duration of the power-law segment of tracer breakthrough curves (BTCs) and the transition rate from anomalous to Fickian transport by determining the solute residence time for a given low-permeability layer, 2) mechanical dispersion has a limited contribution to the anomalous characteristics of late-time transport as compared to molecular diffusion due to an almost negligible velocity in floodplain deposits, and 3) the initial source dimensions only enhance the power-law tail of the BTCs at short travel distances. A tempered stable stochastic (TSS) model is then applied to analyze the modeled transport. Applications show that the time-nonlocal parameters in the TSS model relate to the Peclet number, Pe. In particular, the truncation parameter in the TSS model increases nonlinearly with a decrease in Pe due to the decrease of the mean residence time, and the capacity coefficient increases with an increase in molecular diffusion which is probably due to the increase in the number of immobile particles. The above numerical experiments and stochastic analysis therefore reveal that the Peclet number as affected by molecular diffusion controls transient anomalous transport in alluvial aquifer–aquitard complexes.
Modeling of 1D Anomalous Diffusion in Fractured Nanoporous Media
Directory of Open Access Journals (Sweden)
Albinali Ali
2016-07-01
Full Text Available Fractured nanoporous reservoirs include multi-scale and discontinuous fractures coupled with a complex nanoporous matrix. Such systems cannot be described by the conventional dual-porosity (or multi-porosity idealizations due to the presence of different flow mechanisms at multiple scales. More detailed modeling approaches, such as Discrete Fracture Network (DFN models, similarly suffer from the extensive data requirements dictated by the intricacy of the flow scales, which eventually deter the utility of these models. This paper discusses the utility and construction of 1D analytical and numerical anomalous diffusion models for heterogeneous, nanoporous media, which is commonly encountered in oil and gas production from tight, unconventional reservoirs with fractured horizontal wells. A fractional form of Darcy’s law, which incorporates the non-local and hereditary nature of flow, is coupled with the classical mass conservation equation to derive a fractional diffusion equation in space and time. Results show excellent agreement with established solutions under asymptotic conditions and are consistent with the physical intuitions.
International Nuclear Information System (INIS)
Zhang, Lei; Yang, Si-Gang; Chen, Hong-Wei; Chen, Ming-Hua; Xie, Shi-Zhong; Han, Ying
2013-01-01
Cherenkov radiation (CR) in both the visible and mid-infrared regions is simultaneously generated experimentally based on a photonic crystal fiber with two zero-dispersion wavelengths. The generation of CR in the visible region originates from solitons located in the anomalous group velocity dispersion (GVD) regime which are perturbed by positive third order dispersion. Conversely, the generation of CR in the mid-infrared region requires that the solitons in the anomalous GVD regime are perturbed by negative third order dispersion. The peak wavelength of the CR in the visible region can be tuned from 498 to 425 nm by increasing the average input pump power from 70 to 400 mW, while the peak wavelength of the CR in the mid-infrared region can be tuned from 1986 to 2279 nm by increasing the average input pump power from 70 to 320 mW. (paper)
Directory of Open Access Journals (Sweden)
A. Nazzaro
2002-06-01
Full Text Available Campi Flegrei is a unique volcanic region located near Naples, Italy. Anomalous crustal movements at Pozzuoli in Campi Flegrei have been documented since the Roman period. The movements were gradual and have continued to the present, occasionally accompanying swarms of local earthquakes and volcanic eruptions. Generally the movements proceed with low seismicity. After the 1538 eruption of Monte Nuovo, Pozzuoli had subsided monotonously, but it changed to uplift abruptly in 1969. The uplift accelerated in 1983 and 1984 reaching more than 2 m, and thereafter began to subside. Many discussions of this event have been published. In Japan, we have examples of deformations similar to those at Campi Flegrei, mainly in volcanic areas, and rarely in non-volcanic areas. The former includes Iwojima, Miyakejima and Aira caldera while the latter is represented by Cape Omaezaki. Iwojima is a volcano island, and its secular uplifts since the 18th century are recognized as an unusual event. Miyakejima volcano and Aira caldera exhibited anomalous movements with low seismicity after their eruptions. Cape Omaezaki is not situated in volcanic zone but near a subduction zone, and gradually and continuously subsides as a precursor to a large earthquake. In such cases as Campi Flegrei and the Japanese localities, we would question whether the deformations are accompanied by normal seismicity or low seismicity. To examine quantitatively the relationship between seismicity and related deformation, seismic efficiency is generally useful. The crustal deformations in all the regions cited above are characterized by exceptionally low seismic efficiencies. In the present paper, the deformations at Pozzuoli and Iwojima are mainly described and a comparative discussion among these and other localities in Japan is supplemented. It is concluded that such anomalous phenomena in volcanic areas are attributable to peculiar rheological aspects of the material composing the local
Anomalous Traffic Detection and Self-Similarity Analysis in the Environment of ATMSim
Directory of Open Access Journals (Sweden)
Hae-Duck J. Jeong
2017-12-01
Full Text Available Internet utilisation has steadily increased, predominantly due to the rapid recent development of information and communication networks and the widespread distribution of smartphones. As a result of this increase in Internet consumption, various types of services, including web services, social networking services (SNS, Internet banking, and remote processing systems have been created. These services have significantly enhanced global quality of life. However, as a negative side-effect of this rapid development, serious information security problems have also surfaced, which has led to serious to Internet privacy invasions and network attacks. In an attempt to contribute to the process of addressing these problems, this paper proposes a process to detect anomalous traffic using self-similarity analysis in the Anomaly Teletraffic detection Measurement analysis Simulator (ATMSim environment as a research method. Simulations were performed to measure normal and anomalous traffic. First, normal traffic for each attack, including the Address Resolution Protocol (ARP and distributed denial-of-service (DDoS was measured for 48 h over 10 iterations. Hadoop was used to facilitate processing of the large amount of collected data, after which MapReduce was utilised after storing the data in the Hadoop Distributed File System (HDFS. A new platform on Hadoop, the detection system ATMSim, was used to identify anomalous traffic after which a comparative analysis of the normal and anomalous traffic was performed through a self-similarity analysis. There were four categories of collected traffic that were divided according to the attack methods used: normal local area network (LAN traffic, DDoS attack, and ARP spoofing, as well as DDoS and ARP attack. ATMSim, the anomaly traffic detection system, was used to determine if real attacks could be identified effectively. To achieve this, the ATMSim was used in simulations for each scenario to test its ability to
Search for Anomalous Couplings in the Higgs Sector at LEP
Achard, P; Aguilar-Benítez, M; Alcaraz, J; Alemanni, G; Allaby, James V; Aloisio, A; Alviggi, M G; Anderhub, H; Andreev, V P; Anselmo, F; Arefev, A; Azemoon, T; Aziz, T; Bagnaia, P; Bajo, A; Baksay, G; Baksay, L; Baldew, S V; Banerjee, S; Banerjee, Sw; Barczyk, A; Barillère, R; Bartalini, P; Basile, M; Batalova, N; Battiston, R; Bay, A; Becattini, F; Becker, U; Behner, F; Bellucci, L; Berbeco, R; Berdugo, J; Berges, P; Bertucci, B; Betev, B L; Biasini, M; Biglietti, M; Biland, A; Blaising, J J; Blyth, S C; Bobbink, Gerjan J; Böhm, A; Boldizsar, L; Borgia, B; Bottai, S; Bourilkov, D; Bourquin, Maurice; Braccini, S; Branson, J G; Brochu, F; Burger, J D; Burger, W J; Cai, X D; Capell, M; Cara Romeo, G; Carlino, G; Cartacci, A M; Casaus, J; Cavallari, F; Cavallo, N; Cecchi, C; Cerrada, M; Chamizo-Llatas, M; Chang, Y H; Chemarin, M; Chen, A; Chen, G; Chen, G M; Chen, H F; Chen, H S; Chiefari, G; Cifarelli, Luisa; Cindolo, F; Clare, I; Clare, R; Coignet, G; Colino, N; Costantini, S; de la Cruz, B; Cucciarelli, S; van Dalen, J A; De Asmundis, R; Déglon, P L; Debreczeni, J; Degré, A; Dehmelt, K; Deiters, K; Della Volpe, D; Delmeire, E; Denes, P; De Notaristefani, F; De Salvo, A; Diemoz, M; Dierckxsens, M; Dionisi, C; Dittmar, M; Doria, A; Dova, M T; Duchesneau, D; Duda, M; Echenard, B; Eline, A; El-Hage, A; El-Mamouni, H; Engler, A; Eppling, F J; Extermann, P; Falagán, M A; Falciano, S; Favara, A; Fay, J; Fedin, O; Felcini, M; Ferguson, T; Fesefeldt, H S; Fiandrini, E; Field, J H; Filthaut, F; Fisher, P H; Fisher, W; Fisk, I; Forconi, G; Freudenreich, Klaus; Furetta, C; Galaktionov, Yu; Ganguli, S N; García-Abia, P; Gataullin, M; Gentile, S; Giagu, S; Gong, Z F; Grenier, G; Grimm, O; Grünewald, M W; Guida, M; van Gulik, R; Gupta, V K; Gurtu, A; Gutay, L J; Haas, D; Hatzifotiadou, D; Hebbeker, T; Hervé, A; Hirschfelder, J; Hofer, H; Hohlmann, M; Holzner, G; Hou, S R; Hu, Y; Jin, B N; Jones, L W; de Jong, P; Josa-Mutuberria, I; Kaur, M; Kienzle-Focacci, M N; Kim, J K; Kirkby, Jasper; Kittel, E W; Klimentov, A; König, A C; Kopal, M; Koutsenko, V F; Kräber, M H; Krämer, R W; Krüger, A; Kunin, A; Ladrón de Guevara, P; Laktineh, I; Landi, G; Lebeau, M; Lebedev, A; Lebrun, P; Lecomte, P; Lecoq, P; Le Coultre, P; Le Goff, J M; Leiste, R; Levtchenko, M; Levchenko, P M; Li, C; Likhoded, S; Lin, C H; Lin, W T; Linde, Frank L; Lista, L; Liu, Z A; Lohmann, W; Longo, E; Lü, Y S; Luci, C; Luminari, L; Lustermann, W; Ma Wen Gan; Malgeri, L; Malinin, A; Maña, C; Mans, J; Martin, J P; Marzano, F; Mazumdar, K; McNeil, R R; Mele, S; Merola, L; Meschini, M; Metzger, W J; Mihul, A; Milcent, H; Mirabelli, G; Mnich, J; Mohanty, G B; Muanza, G S; Muijs, A J M; Musicar, B; Musy, M; Nagy, S; Natale, S; Napolitano, M; Nessi-Tedaldi, F; Newman, H; Nisati, A; Novák, T; Nowak, H; Ofierzynski, R A; Organtini, G; Pal, I; Palomares, C; Paolucci, P; Paramatti, R; Passaleva, G; Patricelli, S; Paul, T; Pauluzzi, M; Paus, C; Pauss, Felicitas; Pedace, M; Pensotti, S; Perret-Gallix, D; Petersen, B; Piccolo, D; Pierella, F; Pioppi, M; Piroué, P A; Pistolesi, E; Plyaskin, V; Pohl, M; Pozhidaev, V; Pothier, J; Prokofev, D; Prokofiev, D O; Quartieri, J; Rahal-Callot, G; Rahaman, M A; Raics, P; Raja, N; Ramelli, R; Rancoita, P G; Ranieri, R; Raspereza, A V; Razis, P A; Ren, D; Rescigno, M; Reucroft, S; Riemann, S; Riles, K; Roe, B P; Romero, L; Rosca, A; Rosemann, C; Rosenbleck, C; Rosier-Lees, S; Roth, S; Rubio, J A; Ruggiero, G; Rykaczewski, H; Sakharov, A; Saremi, S; Sarkar, S; Salicio, J; Sánchez, E; Schäfer, C; Shchegelskii, V; Schopper, Herwig Franz; Schotanus, D J; Sciacca, C; Servoli, L; Shevchenko, S; Shivarov, N; Shoutko, V; Shumilov, E; Shvorob, A V; Son, D; Souga, C; Spillantini, P; Steuer, M; Stickland, D P; Stoyanov, B; Strässner, A; Sudhakar, K; Sultanov, G G; Sun, L Z; Sushkov, S; Suter, H; Swain, J D; Szillási, Z; Tang, X W; Tarjan, P; Tauscher, Ludwig; Taylor, L; Tellili, B; Teyssier, D; Timmermans, C; Ting, Samuel C C; Ting, S M; Tonwar, S C; Tóth, J; Tully, C; Tung, K L; Ulbricht, J; Valente, E; Van de Walle, R T; Vásquez, R; Veszpremi, V; Vesztergombi, G; Vetlitskii, I; Vicinanza, D; Viertel, Gert M; Villa, S; Vivargent, M; Vlachos, S; Vodopyanov, I; Vogel, H; Vogt, H; Vorobev, I; Vorobyov, A A; Wadhwa, M; Wang, Q; Wang, X L; Wang, Z M; Weber, M; Wilkens, H; Wynhoff, S; Xia, L; Xu, Z Z; Yamamoto, J; Yang, B Z; Yang, C G; Yang, H J; Yang, M; Yeh, S C; Zalite, A; Zalite, Yu; Zhang, Z P; Zhao, J; Zhu, G Y; Zhu, R Y; Zhuang, H L; Zichichi, A; Zimmermann, B; Zöller, M
2004-01-01
Anomalous couplings of the Higgs boson are searched for through the processes e^+ e^- -> H gamma, e^+ e^- -> e^+ e^- H and e^+ e^- -> HZ. The mass range 70 GeV ffbar, H -> gamma gamma, H -> Z\\gamma and H -> WW^(*) are considered and no evidence is found for anomalous Higgs production or decay. Limits on the anomalous couplings d, db, Delta(g1z), Delta(kappa_gamma) and xi^2 are derived as well as limits on the H -> gamma gamma and H -> Z gamma decay rates.
Anomalous Centrifugal Distortion in NH_2
Martin-Drumel, Marie-Aline; Pirali, Olivier; Coudert, L. H.
2017-06-01
The NH2 radical spectrum, first observed by Herzberg and Ramsay, is dominated by a strong Renner-Teller effect giving rise to two electronic states: the bent X ^{2}B_1 ground state and the quasi-linear A ^{2}A_1 excited state. The NH2 radical has been the subject of numerous high-resolution investigations and its electronic and ro-vibrational transitions have been measured. Using synchrotron radiation, new rotational transitions have been recently recorded and a value of the rotational quantum number N as large as 26 could be reached. In the X ^{2}B_1 ground state, the NH2 radical behaves like a triatomic molecule displaying spin-rotation splittings. Due to the lightness of the molecule, a strong coupling between the overall rotation and the bending mode arises whose effects increase with N and lead to the anomalous centrifugal distortion evidenced in the new measurements.^d In this talk the Bending-Rotation approach developed to account for the anomalous centrifugal distortion of the water molecule is modified to include spin-rotation coupling and applied to the fitting of high-resolution data pertaining to the ground electronic state of NH2. A preliminary line position analysis of the available data^{c,d} allowed us to account for 1681 transitions with a unitless standard deviation of 1.2. New transitions could also be assigned in the spectrum recorded by Martin-Drumel et al.^d In the talk, the results obtained with the new theoretical approach will be compared to those retrieved with a Watson-type Hamiltonian and the effects of the vibronic coupling between the ground X ^{2}B_1 and the excited A ^{2}A_1 electronic state will be discussed. Herzberg and Ramsay, J. Chem. Phys. 20 (1952) 347 Dressler and Ramsay, Phil. Trans. R. Soc. A 25 (1959) 553 Hadj Bachir, Huet, Destombes, and Vervloet, J. Molec. Spectrosc. 193 (1999) 326 McKellar, Vervloet, Burkholder, and Howard, J. Molec. Spectrosc. 142 (1990) 319 Morino and Kawaguchi, J. Molec. Spectrosc. 182 (1997) 428
Czech Academy of Sciences Publication Activity Database
Urbanová, Martina; Šturcová, Adriana; Kredatusová, Jana; Brus, Jiří
2015-01-01
Roč. 478, č. 2 (2015), s. 464-475 ISSN 0378-5173 R&D Projects: GA ČR(CZ) GA14-03636S; GA MŠk(CZ) LD14010 Grant - others:European Commission(XE) COST Action MP1202 HINT Institutional support: RVO:61389013 Keywords : solid dispersions * simvastatin * pharmaceuticals Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.994, year: 2015
Investigation and modeling of the anomalous yield point phenomenon in pure tantalum
Energy Technology Data Exchange (ETDEWEB)
Colas, D. [Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 5209 CNRS, Université de Bourgogne, 9 avenue Alain Savary, BP 17870, 21078 Dijon Cedex (France); CEA Valduc, 21120 Is-sur-Tille (France); Mines ParisTech, Centre des Matériaux, CNRS, UMR 7633, BP 87, 91003 Evry Cedex (France); Finot, E. [Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 5209 CNRS, Université de Bourgogne, 9 avenue Alain Savary, BP 17870, 21078 Dijon Cedex (France); Flouriot, S. [CEA Valduc, 21120 Is-sur-Tille (France); Forest, S. [Mines ParisTech, Centre des Matériaux, CNRS, UMR 7633, BP 87, 91003 Evry Cedex (France); Mazière, M., E-mail: matthieu.maziere@mines-paristech.fr [Mines ParisTech, Centre des Matériaux, CNRS, UMR 7633, BP 87, 91003 Evry Cedex (France); Paris, T. [CEA Valduc, 21120 Is-sur-Tille (France)
2014-10-06
The monotonic and cyclic behavior of commercially pure tantalum has been investigated at room temperature, in order to capture and understand the occurrence of the anomalous yield point phenomenon. Interrupted tests have been performed, with strain reversals (tensile or compressive loading) after an aging period. The stress drop is attributed to the interactions between dislocations and solute atoms (oxygen) and its macroscopic occurrence is not systematically observed. InfraRed Thermography (IRT) measurements supported by Scanning Electron Microscopy (SEM) pictures of the polished gauge length of a specimen during an interrupted tensile test reveal the nucleation and propagation of a strain localization band. The KEMC (Kubin–Estrin–McCormick) phenomenological model accounting for strain aging has been identified for several loadings and strain rates at room temperature. Simulations on full specimen using the KEMC model do not show strain localization, because of the competition between viscosity and strain localization. However, a slight misalignment of the sample can promote strain localization.
Keiser, Dennis D.; Williams, Walter; Robinson, Adam; Wachs, Dan; Moore, Glenn; Crawford, Doug
2017-10-01
The Materials Management and Minimization program is developing fuel designs to replace highly enriched fuel with fuels of low enrichment. Swelling is an important irradiation behavior that needs to be well understood. Data from high resolution thickness measurements performed on U-7Mo dispersion fuel plates with Al-Si alloy matrices that were irradiated at high power is sparse. This paper reports the results of detailed thickness measurements performed on two dispersion fuel plates that were irradiated at relatively high power to high fission densities in the Advanced Test Reactor in the same RERTR-9B experiment. Both plates were irradiated to similar fission densities, but one was irradiated at a higher power than the other. The goal of this work is to identify any differences in the swelling behavior when fuel plates are irradiated at different powers to the same fission densities. Based on the results of detailed thickness measurments, more swelling occurs when a U-7Mo dispersion fuel with Al-3.5Si matrix is irradiated to a high fission density at high power compared to one irradiated at a lower power to high fission density.
Effects of different dispersal patterns on the presence-absence of multiple species
Mohd, Mohd Hafiz; Murray, Rua; Plank, Michael J.; Godsoe, William
2018-03-01
Predicting which species will be present (or absent) across a geographical region remains one of the key problems in ecology. Numerous studies have suggested several ecological factors that can determine species presence-absence: environmental factors (i.e. abiotic environments), interactions among species (i.e. biotic interactions) and dispersal process. While various ecological factors have been considered, less attention has been given to the problem of understanding how different dispersal patterns, in interaction with other factors, shape community assembly in the presence of priority effects (i.e. where relative initial abundances determine the long-term presence-absence of each species). By employing both local and non-local dispersal models, we investigate the consequences of different dispersal patterns on the occurrence of priority effects and coexistence in multi-species communities. In the case of non-local, but short-range dispersal, we observe agreement with the predictions of local models for weak and medium dispersal strength, but disagreement for relatively strong dispersal levels. Our analysis shows the existence of a threshold value in dispersal strength (i.e. saddle-node bifurcation) above which priority effects disappear. These results also reveal a co-dimension 2 point, corresponding to a degenerate transcritical bifurcation: at this point, the transcritical bifurcation changes from subcritical to supercritical with corresponding creation of a saddle-node bifurcation curve. We observe further contrasting effects of non-local dispersal as dispersal distance changes: while very long-range dispersal can lead to species extinctions, intermediate-range dispersal can permit more outcomes with multi-species coexistence than short-range dispersal (or purely local dispersal). Overall, our results show that priority effects are more pronounced in the non-local dispersal models than in the local dispersal models. Taken together, our findings highlight
Anomalous transport from holography. Part I
Energy Technology Data Exchange (ETDEWEB)
Bu, Yanyan [Department of Physics, Ben-Gurion University of the Negev,Beer-Sheva 84105 (Israel); Lublinsky, Michael [Department of Physics, Ben-Gurion University of the Negev,Beer-Sheva 84105 (Israel); Physics Department, University of Connecticut,2152 Hillside Road, Storrs, CT 06269-3046 (United States); Sharon, Amir [Department of Physics, Ben-Gurion University of the Negev,Beer-Sheva 84105 (Israel)
2016-11-17
We revisit the transport properties induced by the chiral anomaly in a charged plasma holographically dual to anomalous U(1){sub V}×U(1){sub A} Maxwell theory in Schwarzschild-AdS{sub 5}. Off-shell constitutive relations for vector and axial currents are derived using various approximations generalising most of known in the literature anomaly-induced phenomena and revealing some new ones. In a weak external field approximation, the constitutive relations have all-order derivatives resummed into six momenta-dependent transport coefficient functions: the diffusion, the electric/magnetic conductivity, and three anomaly induced functions. The latter generalise the chiral magnetic and chiral separation effects. Nonlinear transport is studied assuming presence of constant background external fields. The chiral magnetic effect, including all order nonlinearity in magnetic field, is proven to be exact when the magnetic field is the only external field that is turned on. Non-linear corrections to the constitutive relations due to electric and axial external fields are computed.
Anomalous transport from holography. Pt. II
International Nuclear Information System (INIS)
Bu, Yanyan; Sharon, Amir; Lublinsky, Michael
2017-01-01
This is a second study of chiral anomaly-induced transport within a holographic model consisting of anomalous U(1)_V x U(1)_A Maxwell theory in Schwarzschild-AdS_5 spacetime. In the first part, chiral magnetic/separation effects (CME/CSE) are considered in the presence of a static spatially inhomogeneous external magnetic field. Gradient corrections to CME/CSE are analytically evaluated up to third order in the derivative expansion. Some of the third order gradient corrections lead to an anomaly-induced negative B"2-correction to the diffusion constant. We also find modifications to the chiral magnetic wave nonlinear in B. In the second part, we focus on the experimentally interesting case of the axial chemical potential being induced dynamically by a constant magnetic and time-dependent electric fields. Constitutive relations for the vector/axial currents are computed employing two different approximations: (a) derivative expansion (up to third order) but fully nonlinear in the external fields, and (b) weak electric field limit but resuming all orders in the derivative expansion. A non-vanishing nonlinear axial current (CSE) is found in the first case. The dependence on magnetic field and frequency of linear transport coefficient functions is explored in the second. (orig.)
Anomalous water diffusion in salt solutions
Ding, Yun; Hassanali, Ali A.; Parrinello, Michele
2014-01-01
The dynamics of water exhibits anomalous behavior in the presence of different electrolytes. Recent experiments [Kim JS, Wu Z, Morrow AR, Yethiraj A, Yethiraj A (2012) J Phys Chem B 116(39):12007–12013] have found that the self-diffusion of water can either be enhanced or suppressed around CsI and NaCl, respectively, relative to that of neat water. Here we show that unlike classical empirical potentials, ab initio molecular dynamics simulations successfully reproduce the qualitative trends observed experimentally. These types of phenomena have often been rationalized in terms of the “structure-making” or “structure-breaking” effects of different ions on the solvent, although the microscopic origins of these features have remained elusive. Rather than disrupting the network in a significant manner, the electrolytes studied here cause rather subtle changes in both structural and dynamical properties of water. In particular, we show that water in the ab initio molecular dynamics simulations is characterized by dynamic heterogeneity, which turns out to be critical in reproducing the experimental trends. PMID:24522111
Diagnosing Anomalous Network Performance with Confidence
Energy Technology Data Exchange (ETDEWEB)
Settlemyer, Bradley W [ORNL; Hodson, Stephen W [ORNL; Kuehn, Jeffery A [ORNL; Poole, Stephen W [ORNL
2011-04-01
Variability in network performance is a major obstacle in effectively analyzing the throughput of modern high performance computer systems. High performance interconnec- tion networks offer excellent best-case network latencies; how- ever, highly parallel applications running on parallel machines typically require consistently high levels of performance to adequately leverage the massive amounts of available computing power. Performance analysts have usually quantified network performance using traditional summary statistics that assume the observational data is sampled from a normal distribution. In our examinations of network performance, we have found this method of analysis often provides too little data to under- stand anomalous network performance. Our tool, Confidence, instead uses an empirically derived probability distribution to characterize network performance. In this paper we describe several instances where the Confidence toolkit allowed us to understand and diagnose network performance anomalies that we could not adequately explore with the simple summary statis- tics provided by traditional measurement tools. In particular, we examine a multi-modal performance scenario encountered with an Infiniband interconnection network and we explore the performance repeatability on the custom Cray SeaStar2 interconnection network after a set of software and driver updates.
Anomalous transport from holography. Pt. II
Energy Technology Data Exchange (ETDEWEB)
Bu, Yanyan; Sharon, Amir [Ben-Gurion University of the Negev, Department of Physics, Beersheba (Israel); Lublinsky, Michael [Ben-Gurion University of the Negev, Department of Physics, Beersheba (Israel); University of Connecticut, Physics Department, Storrs, CT (United States)
2017-03-15
This is a second study of chiral anomaly-induced transport within a holographic model consisting of anomalous U(1){sub V} x U(1){sub A} Maxwell theory in Schwarzschild-AdS{sub 5} spacetime. In the first part, chiral magnetic/separation effects (CME/CSE) are considered in the presence of a static spatially inhomogeneous external magnetic field. Gradient corrections to CME/CSE are analytically evaluated up to third order in the derivative expansion. Some of the third order gradient corrections lead to an anomaly-induced negative B{sup 2}-correction to the diffusion constant. We also find modifications to the chiral magnetic wave nonlinear in B. In the second part, we focus on the experimentally interesting case of the axial chemical potential being induced dynamically by a constant magnetic and time-dependent electric fields. Constitutive relations for the vector/axial currents are computed employing two different approximations: (a) derivative expansion (up to third order) but fully nonlinear in the external fields, and (b) weak electric field limit but resuming all orders in the derivative expansion. A non-vanishing nonlinear axial current (CSE) is found in the first case. The dependence on magnetic field and frequency of linear transport coefficient functions is explored in the second. (orig.)
Anomalous Anticipatory Responses in Networked Random Data
International Nuclear Information System (INIS)
Nelson, Roger D.; Bancel, Peter A.
2006-01-01
We examine an 8-year archive of synchronized, parallel time series of random data from a world spanning network of physical random event generators (REGs). The archive is a publicly accessible matrix of normally distributed 200-bit sums recorded at 1 Hz which extends from August 1998 to the present. The primary question is whether these data show non-random structure associated with major events such as natural or man-made disasters, terrible accidents, or grand celebrations. Secondarily, we examine the time course of apparently correlated responses. Statistical analyses of the data reveal consistent evidence that events which strongly affect people engender small but significant effects. These include suggestions of anticipatory responses in some cases, leading to a series of specialized analyses to assess possible non-random structure preceding precisely timed events. A focused examination of data collected around the time of earthquakes with Richter magnitude 6 and greater reveals non-random structure with a number of intriguing, potentially important features. Anomalous effects in the REG data are seen only when the corresponding earthquakes occur in populated areas. No structure is found if they occur in the oceans. We infer that an important contributor to the effect is the relevance of the earthquake to humans. Epoch averaging reveals evidence for changes in the data some hours prior to the main temblor, suggestive of reverse causation
Drift wave vortices and anomalous transport
International Nuclear Information System (INIS)
Horton, W.
1990-01-01
Many plasma equations for drift waves and other modes possess vortex solutions, so it is important to consider the transport associated with vortex structures and their mutual interactions. Vortex structures occur when the amplitude of the fluctuation is sufficient to trap and circulate plasma around the vortex in one wave period. The vortex contribution of the diffusion of the passively convected scalar field was calculated. It was found that the field can be represented by the superposition of vortices and wave fluctuation components. For transport the computer solutions for the vortex-vortex collisions with various impact parameters while carrying along the passively convected scalar thermodynamic field were used. As the result, the inelastic collisions with b≅r 0 ≅1/k x cross-section σ(b)≅b exp(-b/r 0 )≅r 0 give the strongest transport. An example is shown in figure. As the final result, the anomalous diffusion D was derived in dimensional form. (M.T.)
Anomalous Solubility Behavior of Several Acidic Drugs
Directory of Open Access Journals (Sweden)
Alex Avdeef
2014-04-01
Full Text Available The “anomalous solubility behavior at higher pH values” of several acidic drugs originally studied by Higuchi et al. in 1953 [1], but hitherto not fully rationalized, has been re-analyzed using a novel solubility-pH analysis computer program, pDISOL-XTM. The program internally derives implicit solubility equations, given a set of proposed equilibria and constants (iteratively refined by weighted nonlinear regression, and does not require explicit Henderson-Hasselbalch equations. The re-analyzed original barbital, phenobarbital, oxytetracycline, and sulfathiazole solubility-pH data of Higuchi et al. is consistent with the presence of dimers in saturated solutions. In the case of barbital, phenobarbital and sulfathiazole, anionic dimers, reaching peak concentrations near pH 8. However, oxytetracycline indicated a pronounced tendency to form a cationic dimer, peaking near pH 2. Under the conditions of the original study, only barbital indicated a slight tendency to form a salt precipitate at pH > 6.8, with a highly unusual stoichiometry (consistent with a slope of 0.55 in the log S – pH plot: K+ + A2H- + 3HA D KA5H4(s. Thus the “anomaly” in the Higuchi data can be rationalized by invoking specific aggregated species.
Mechanisms of anomalous compressibility of vitreous silica
Clark, Alisha N.; Lesher, Charles E.; Jacobsen, Steven D.; Sen, Sabyasachi
2014-11-01
The anomalous compressibility of vitreous silica has been known for nearly a century, but the mechanisms responsible for it remain poorly understood. Using GHz-ultrasonic interferometry, we measured longitudinal and transverse acoustic wave travel times at pressures up to 5 GPa in vitreous silica with fictive temperatures (Tf) ranging between 985 °C and 1500 °C. The maximum in ultrasonic wave travel times-corresponding to a minimum in acoustic velocities-shifts to higher pressure with increasing Tf for both acoustic waves, with complete reversibility below 5 GPa. These relationships reflect polyamorphism in the supercooled liquid, which results in a glassy state possessing different proportions of domains of high- and low-density amorphous phases (HDA and LDA, respectively). The relative proportion of HDA and LDA is set at Tf and remains fixed on compression below the permanent densification pressure. The bulk material exhibits compression behavior systematically dependent on synthesis conditions that arise from the presence of floppy modes in a mixture of HDA and LDA domains.
Are anomalously short tunnelling times measurable?
International Nuclear Information System (INIS)
Delgado, V.; Muga, J.G.
1996-01-01
Low and Mende have analyzed the conditions that would make possible an actual measurement of an anomalously short traversal time through a potential barrier concluding that such a measurement cannot be made because it is not possible to describe the tunnelling of a wave packet initially close to the barrier by the open-quote open-quote usual wave packet space time analysis close-quote close-quote. We complement this work in several ways: It is argued that the described failure of the usual formalism occurs under a set of too restrictive conditions, some of them not physically motivated, so it does not necessarily imply the impossibility of such a measurement. However, by retaining only conditions well motivated on physical grounds we have performed a systematic numerical check which shows that the conclusion by Low and Mende is indeed generally valid. It is shown that, as speculated by Low and Mende, the process is dominated by over the barrier transmission. Copyright copyright 1996 Academic Press, Inc
Anomalous transport from holography. Part I
International Nuclear Information System (INIS)
Bu, Yanyan; Lublinsky, Michael; Sharon, Amir
2016-01-01
We revisit the transport properties induced by the chiral anomaly in a charged plasma holographically dual to anomalous U(1)_V×U(1)_A Maxwell theory in Schwarzschild-AdS_5. Off-shell constitutive relations for vector and axial currents are derived using various approximations generalising most of known in the literature anomaly-induced phenomena and revealing some new ones. In a weak external field approximation, the constitutive relations have all-order derivatives resummed into six momenta-dependent transport coefficient functions: the diffusion, the electric/magnetic conductivity, and three anomaly induced functions. The latter generalise the chiral magnetic and chiral separation effects. Nonlinear transport is studied assuming presence of constant background external fields. The chiral magnetic effect, including all order nonlinearity in magnetic field, is proven to be exact when the magnetic field is the only external field that is turned on. Non-linear corrections to the constitutive relations due to electric and axial external fields are computed.
Phonon dispersion curves of fcc La
International Nuclear Information System (INIS)
Stassis, C.; Loong, C.; Zarestky, J.
1982-01-01
Large single crystals of fcc La were grown in situ and were used to study the lattice dynamics of this phase of La by coherent inelastic neutron scattering. The phonon dispersion curves have been measured along the [xi00], [xixi0], [xixixi], and [0xi1] symmetry directions at 660 and 1100 K. The T[xixixi] branch exhibits anomalous dispersion for xi>0.25 and, in addition, close to the zone boundary, the phonon frequencies of this branch decrease with decreasing temperature. This soft-mode behavior may be related to the #betta→α# transformation in La, an assumption supported by recent band-theoretical calculations of the generalized susceptibility of fcc La. At X the frequencies of the L[xi00] branch are considerably lower than those of the corresponding branch of #betta#-Ce; a similar but not as pronounced effect is observed for the frequencies of the L[xixixi] branch close to the point L. Since the calculated generalized susceptibility of fcc La exhibits strong peaks at X and L, these anomalies may be due to the renormalization of the phonon frequencies by virtual fbold-arrow-left-rightd transitions to the unoccupied 4f level in La. The data were used to evaluate the elastic constants, the phonon density of states, and the lattice specific heat at constant pressure C/sub P//sup
Employment Effects of Spatial Dispersal of Refugees
Anna Piil Damm; Michael Rosholm
2006-01-01
Spatial dispersal policies may influence labour market integration of refugees through two mechanisms. First, it may affect the local job offer arrival rate, and second, it may affect place utility. We investigate the second mechanism theoretically by formulating a partial search model in which an individual searches simultaneously for a job and for a new residential location. The model predicts that the reservation wage for local jobs is decreasing in place utility. We argue that spatial dis...
Overseas seed dispersal by migratory birds
Viana, D.S.; Gangoso, L.; Bouten, W.; Figuerola, J.
2016-01-01
Long-distance dispersal (LDD) promotes the colonization of isolated and remote habitats, and thus it has been proposed as a mechanism for explaining the distributions of many species. Birds are key LDD vectors for many sessile organisms such as plants, yet LDD beyond local and regional scales has
International Nuclear Information System (INIS)
Rahm, L.; Nyberg, L.; Gidhagen, L.
1990-01-01
A dispersion model to be used off costal waters has been developed. The model has been applied to describe the migration of radionuclides in the Baltic sea. A summary of the results is presented here. (K.A.E)
Wave-equation dispersion inversion
Li, Jing; Feng, Zongcai; Schuster, Gerard T.
2016-01-01
We present the theory for wave-equation inversion of dispersion curves, where the misfit function is the sum of the squared differences between the wavenumbers along the predicted and observed dispersion curves. The dispersion curves are obtained
Partial anomalous pulmonary venous return in patients with pulmonary hypertension
International Nuclear Information System (INIS)
Sung, Won-kyung; Au, Virginia; Rose, Anand
2012-01-01
Anomalous pulmonary venous return is an uncommon congenital malformation, and may be partial or total. Partial anomalous pulmonary venous return (PAPVR) is more common than total anomalous pulmonary venous return, and is often associated with other congenital cardiac anomalies. Whilst many patients with PAPVR remain asymptomatic, some may present in later age with symptoms related to left-to-right shunt, right heart failure and pulmonary hypertension. We report two cases of PAPVR detected on Computed Tomography Pulmonary Angiogram (CTPA) for the work up of pulmonary hypertension. The cases demonstrate that, although uncommon, partial anomalous pulmonary venous return can be a contributing factor to pulmonary hypertension and pulmonary veins should be carefully examined when reading a CTPA study.
The relation between anomalous magnetic moment and axial anomaly
International Nuclear Information System (INIS)
Teryaev, O.V.
1990-12-01
The conservation of total angular momentum of spinor particle leads to a simple relation between the famous Schwinger and Adler coefficients determining axial anomaly and anomalous magnetic moment, respectively. (author). 8 refs, 1 fig
Anomalous superconductivity in black phosphorus under high pressures
International Nuclear Information System (INIS)
Kawamura, H.; Tachikawa, K.
1984-01-01
Pressure induced superconductivity in single crystals of black phosphorus has been studied. Maximum onset Tsub(c) was near 13 K. The anomalous superconductivity may be explained in terms of excitonic mechanism. (author)
Anomalous magnon Nernst effect of topological magnonic materials
Wang, X. S.; Wang, X. R.
2018-05-01
The magnon transport driven by a thermal gradient in a perpendicularly magnetized honeycomb lattice is studied. The system with the nearest-neighbor pseudodipolar interaction and the next-nearest-neighbor Dzyaloshinskii–Moriya interaction has various topologically nontrivial phases. When an in-plane thermal gradient is applied, a transverse in-plane magnon current is generated. This phenomenon is termed as the anomalous magnon Nernst effect that closely resembles the anomalous Nernst effect for an electronic system. The anomalous magnon Nernst coefficient and its sign are determined by the magnon Berry curvature distributions in the momentum space and magnon populations in the magnon bands. We predict a temperature-induced sign reversal in anomalous magnon Nernst effect under certain conditions.
Anomalous scaling of a scalar field advected by turbulence
Energy Technology Data Exchange (ETDEWEB)
Kraichnan, R.H. [Robert H. Kraichnan, Inc., Santa Fe, NM (United States)
1995-12-31
Recent work leading to deduction of anomalous scaling exponents for the inertial range of an advected passive field from the equations of motion is reviewed. Implications for other turbulence problems are discussed.
Anomalous transient behavior from an inhomogeneous initial optical vortex density
CSIR Research Space (South Africa)
Roux, FS
2011-04-01
Full Text Available . However, the decay curves contain oscillatory features that are counterintuitive: for a short while, the inhomogeneity actually increases. The author provides numerical simulations and analytic calculations to study the appearance of the anomalous features...
Anomalous dynamics of capillary rise in porous media
Shikhmurzaev, Yulii D.; Sprittles, James E.
2012-01-01
The anomalous dynamics of capillary rise in a porous medium discovered experimentally more than a decade ago is described. The developed theory is based on considering the principal modes of motion of the menisci that collectively form the wetting
Reactimeter dispersion equation
A.G. Yuferov
2016-01-01
The aim of this work is to derive and analyze a reactimeter metrological model in the form of the dispersion equation which connects reactimeter input/output signal dispersions with superimposed random noise at the inlet. It is proposed to standardize the reactimeter equation form, presenting the main reactimeter computing unit by a convolution equation. Hence, the reactimeter metrological characteristics are completely determined by this unit hardware function which represents a transient re...
Anomalous anisotropic compression behavior of superconducting CrAs under high pressure
Yu, Zhenhai; Wu, Wei; Hu, Qingyang; Zhao, Jinggeng; Li, Chunyu; Yang, Ke; Cheng, Jinguang; Luo, Jianlin; Wang, Lin; Mao, Ho-kwang
2015-01-01
CrAs was observed to possess the bulk superconductivity under high-pressure conditions. To understand the superconducting mechanism and explore the correlation between the structure and superconductivity, the high-pressure structural evolution of CrAs was investigated using the angle-dispersive X-ray diffraction (XRD) method. The structure of CrAs remains stable up to 1.8 GPa, whereas the lattice parameters exhibit anomalous compression behaviors. With increasing pressure, the lattice parameters a and c both demonstrate a nonmonotonic change, and the lattice parameter b undergoes a rapid contraction at ∼0.18−0.35 GPa, which suggests that a pressure-induced isostructural phase transition occurs in CrAs. Above the phase transition pressure, the axial compressibilities of CrAs present remarkable anisotropy. A schematic band model was used to address the anomalous compression behavior of CrAs. The present results shed light on the structural and related electronic responses to high pressure, which play a key role toward understanding the superconductivity of CrAs. PMID:26627230
Anomalous lattice compressibility of hexagonal Eu{sub 2}O{sub 3}
Energy Technology Data Exchange (ETDEWEB)
Irshad, K.A.; Chandra Shekar, N.V., E-mail: chandru@igcar.gov.in
2017-07-01
Monoclinic Eu{sub 2}O{sub 3} was investigated in a Mao-Bell type diamond anvil cell using angle dispersive x-ray diffraction up to a pressure of 26 GPa. Pressure induced structural phase transition from monoclinic to hexagonal phase was observed at 4.3 GPa with 2% volume collapse. Birch –Murnaghan equation of state fit to the pressure volume data yielded a bulk modulus of 159(9) GPa and 165(6) GPa for the monoclinic and hexagonal phases respectively. Equation of state fitting to the structural parameters yielded an axial compressibility of β{sub a} > β{sub c} > β{sub b} for the parent monoclinic phase, showing the least compressibility along b axis. Contrary to the available reports, an anomalous lattice compressibility behavior is observed for the high pressure hexagonal phase, characterized by pronounced hardening of a axis above 15 GPa. The observed incompressible nature of the hexagonal a axis in the pressure range 15–25 GPa is found to be compensated by doubling the compressibility along the c axis. - Highlights: • Structural phase transition in Eu{sub 2}O{sub 3} from monoclinic to hexagonal phase. • Anomalous lattice compressibility in the hexagonal phase has reported first time. • Quantitative analysis of lattice compressibility.
Effect of anomalous resistivity on the dynamics of plasma switching
Energy Technology Data Exchange (ETDEWEB)
Kingsep, A [Kurchatov Institute, Moscow (Russian Federation); Munier, A [Centre d` Etudes Limeil-Vaneton, Villeneuve St. Georges (France)
1997-12-31
Some of the conditions for electron MHD are recollected, and it is shown how this leads to anomalous resistivity which may play an important role in the dynamics of POS. It has been shown that not only the order of value of the resistance of the plasma-filled diode but rather basic scalings have to be changed in the regime of essential anomalous resistivity. (author). 11 refs.
Anomalous magnon Nernst effect of topological magnonic materials
Wang, X. S.; Wang, X. R.
2017-01-01
The magnon transport driven by thermal gradient in a perpendicularly magnetized honeycomb lattice is studied. The system with the nearest-neighbor pseudodipolar interaction and the next-nearest-neighbor Dzyaloshinskii-Moriya interaction (DMI) has various topologically nontrivial phases. When an in-plane thermal gradient is applied, a transverse in-plane magnon current is generated. This phenomenon is termed as the anomalous magnon Nernst effect that closely resembles the anomalous Nernst effe...
Four-fermi anomalous dimension with adjoint fermions
Del Debbio, Luigi; Ruano, Carlos Pena
2014-01-01
The four-fermi interaction can play an important role in models of strong dynamical EW sym- metry breaking if the anomalous dimensions of the four-fermi operators become large in the IR. We discuss a number of issues that are relevant for the nonperturbative computation of the four- fermi anomalous dimensions for the SU(2) gauge theory with two flavors of Dirac fermions in the adjoint representation, using a Schrödinger functional formalism.
chi2 analyses of data on relativistic anomalous projectile fragments
International Nuclear Information System (INIS)
MacGregor, M.H.
1983-01-01
Nuclear emulsion data from four experimental groups are now available on the interactions of p relativistic anomalous projectile fragments. In the present paper we systematically combine these data together to form several different data sets, which are used to carry out a series of chi 2 parameter studies. The anomalous particle fragment component in the relativistic nuclear beam has been characterized previously in terms of the parameters f and lambda, where f is the anomalous particle fragment fraction in the secondary beam and lambda is the average anomalous particle fragment mean free path in the emulsion. We extend this result here by setting lambda = lambda 0 (2Z)/sup -beta/, where Z is the nuclear charge of the anomalous particle fragment, so that we can investigate the Z dependence of lambda. We also investigate isotopic effects in the equations used to describe ''normal'' secondary beam nuclei, and we examine the problem of optimizing the bin sizes used to represent the data. A series of (f,lambda 0 ,#betta#) parameter studies leads to the conclusion that the ''anomalous particle fragment effect'' exists for all Z values in the range Z = 3--26 included in the chi 2 analyses. These chi 2 analyses also indicate that #betta#>0, so that the anomalous particle fragment lambda's are Z dependent, but the data are not sufficient to pin down a definite value of #betta#. In order to assess the physical content of these results, we define a domain within which nuclear mean free paths can be accounted for by conventional nuclear forces (but not necessarily by conventional nuclear structure). The Z-dependent anomalous particle fragment mean free paths lie approximately on the boundary of this domain
Anomalous transport in fluid field with random waiting time depending on the preceding jump length
International Nuclear Information System (INIS)
Zhang Hong; Li Guo-Hua
2016-01-01
Anomalous (or non-Fickian) transport behaviors of particles have been widely observed in complex porous media. To capture the energy-dependent characteristics of non-Fickian transport of a particle in flow fields, in the present paper a generalized continuous time random walk model whose waiting time probability distribution depends on the preceding jump length is introduced, and the corresponding master equation in Fourier–Laplace space for the distribution of particles is derived. As examples, two generalized advection-dispersion equations for Gaussian distribution and lévy flight with the probability density function of waiting time being quadratic dependent on the preceding jump length are obtained by applying the derived master equation. (paper)
Anomalous transport in fluid field with random waiting time depending on the preceding jump length
Zhang, Hong; Li, Guo-Hua
2016-11-01
Anomalous (or non-Fickian) transport behaviors of particles have been widely observed in complex porous media. To capture the energy-dependent characteristics of non-Fickian transport of a particle in flow fields, in the present paper a generalized continuous time random walk model whose waiting time probability distribution depends on the preceding jump length is introduced, and the corresponding master equation in Fourier-Laplace space for the distribution of particles is derived. As examples, two generalized advection-dispersion equations for Gaussian distribution and lévy flight with the probability density function of waiting time being quadratic dependent on the preceding jump length are obtained by applying the derived master equation. Project supported by the Foundation for Young Key Teachers of Chengdu University of Technology, China (Grant No. KYGG201414) and the Opening Foundation of Geomathematics Key Laboratory of Sichuan Province, China (Grant No. scsxdz2013009).
Low-loss and broadband anomalous Floquet topological insulator for airborne sound
Peng, Yu-Gui; Shen, Ya-Xi; Zhao, De-Gang; Zhu, Xue-Feng
2017-04-01
Anomalous Floquet topological insulators (AFIs) for airborne sound have recently been realized in experiments. However, the implemented version suffers from significant loss and narrowband due to thermal viscosity and dispersive coupling strength between unit-cells. Here, we propose a solution for realizing low-loss and broadband acoustic AFI. We show that the loss after passing through one unit-cell can be less than 2% for the topological edge states. It is also theoretically unveiled that in the frequency range of nearly unitary coupling (˜0.97 from 4.8 kHz to 7.0 kHz in our case), around 84% corresponds to topological bands. Our proposal may promote the application of large-dimension acoustic topological devices.
Electron-temperature-gradient-driven drift waves and anomalous electron energy transport
International Nuclear Information System (INIS)
Shukla, P.K.; Murtaza, G.; Weiland, J.
1990-01-01
By means of a kinetic description for ions and Braginskii's fluid model for electrons, three coupled nonlinear equations governing the dynamics of low-frequency short-wavelength electrostatic waves in the presence of equilibrium density temperature and magnetic-field gradients in a two-component magnetized plasma are derived. In the linear limit a dispersion relation that admits new instabilities of drift waves is presented. An estimate of the anomalous electron energy transport due to non-thermal drift waves is obtained by making use of the saturated wave potential, which is deduced from the mixing-length hypothesis. Stationary solutions of the nonlinear equations governing the interaction of linearly unstable drift waves are also presented. The relevance of this investigation to wave phenomena in space and laboratory plasmas is pointed out. (author)
Effect of entropy on anomalous transport in ITG-modes of magneto-plasma
Yaqub Khan, M.; Qaiser Manzoor, M.; Haq, A. ul; Iqbal, J.
2017-04-01
The ideal gas equation and S={{c}v}log ≤ft(P/ρ \\right) (where S is entropy, P is pressure and ρ is the mass density) define the interconnection of entropy with the temperature and density of plasma. Therefore, different phenomena relating to plasma and entropy need to be investigated. By employing the Braginskii transport equations for a nonuniform electron-ion magnetoplasma, two new parameters—the entropy distribution function and the entropy gradient drift—are defined, a new dispersion relation is obtained, and the dependence of anomalous transport on entropy is also proved. Some results, like monotonicity, the entropy principle and the second law of thermodynamics, are proved with a new definition of entropy. This work will open new horizons in fusion processes, not only by controlling entropy in tokamak plasmas—particularly in the pedestal regions of the H-mode and space plasmas—but also in engineering sciences.
Anomalous photovoltaic effect in organic-inorganic hybrid perovskite solar cells.
Yuan, Yongbo; Li, Tao; Wang, Qi; Xing, Jie; Gruverman, Alexei; Huang, Jinsong
2017-03-01
Organic-inorganic hybrid perovskites (OIHPs) have been demonstrated to be highly successful photovoltaic materials yielding very-high-efficiency solar cells. We report the room temperature observation of an anomalous photovoltaic (APV) effect in lateral structure OIHP devices manifested by the device's open-circuit voltage ( V OC ) that is much larger than the bandgap of OIHPs. The persistent V OC is proportional to the electrode spacing, resembling that of ferroelectric photovoltaic devices. However, the APV effect in OIHP devices is not caused by ferroelectricity. The APV effect can be explained by the formation of tunneling junctions randomly dispersed in the polycrystalline films, which allows the accumulation of photovoltage at a macroscopic level. The formation of internal tunneling junctions as a result of ion migration is visualized with Kelvin probe force microscopy scanning. This observation points out a new avenue for the formation of large and continuously tunable V OC without being limited by the materials' bandgap.
Computer simulation of the anomalous elastic behavior of thin films and superlattices
International Nuclear Information System (INIS)
Wolf, D.
1992-10-01
Atomistic simulations are reviewed that elucidate the causes of the anomalous elastic behavior of thin films and superlattices (the so-called supermodulus effect). The investigation of free-standing thin films and of superlattices of grain boundaries shows that the supermodulus effect is not an electronic but a structural interface effect intricately connected with the local atomic disorder at the interfaces. The consequent predictions that (1) coherent strained-layer superlattices should show the smallest elastic anomalies and (2) the introduction of incoherency at the interfaces should enhance all anomalies are validated by simulations of dissimilar-material superlattices. 38 refs, 10 figs
Directory of Open Access Journals (Sweden)
Saveliev A.N.
2012-09-01
Full Text Available In the paper the possibility of total 3D trapping of electron Bernstein (EB waves in the tokamak equatorial plane in the vicinity of the local density maximum produced by electron pump-out-effect is demonstrated. Thresholds and growth rates of the associated absolute (temporally growing parametric decay instability (PDI leading to anomalous absorption is predicted in the range of less than 100 kW. Its possible role in explanation of ion acceleration observed in ECRH experiments as well as in redistribution of the deposited power is discussed.
Anomalous vibrational modes in acetanilide: a F.D.S. incoherent inelastic neutron scattering study
Barthes, Mariette; Eckert, Juergen; Johnson, Susanna W.; Moret, Jacques; Swanson, Basil I.; Unkefer, Clifford J.
The origin of the anomalous infra-red and Raman modes in acetanilide (C6H5NHCOCH3, or ACN)(1) , remains a subject of considerable controversy. One family of theoretical models involves Davydov-like solitons (2) nonlinear vibrational coupling (3), or "polaronic" localized modes (4)(5). An alternative interpretation of the extra-bands in terms of a Fermi resonance was proposed (6) and recently the existence of slightly non-degenerate hydrogen atom configurations (7) in the H-bond was suggested as an explanation for the anomalies.
Anomalous baryogenesis at the weak scale
Energy Technology Data Exchange (ETDEWEB)
Singleton, R.L. Jr.
1991-06-01
One of the fundamental constants of nature is the baryon asymmetry of the universe -- the ratio of the number of baryons to the entropy. This constant is about 10{sup {minus}11}. In baryon- number conserving theories, this was just an initial condition. With the advent of the grand unified theories (GUTs), baryon number is no longer conserved, and this asymmetry can be generated dynamically. Unfortunately, however, there are reasons for preferring another mechanism. For example, GUTs predict proton decay which, after extensive searches, has not been found. An alternative place to look for baryogenesis is the electroweak phase transition, described by the standard model, which posses all the necessary ingredients for baryogenesis. Anomalous baryon-number violation in weak interactions becomes large at high temperatures, which offers the prospect of creating the asymmetry with the standard model or minimal extensions. This can just barely be done if certain conditions are fulfilled. CP violation must be large, which rules out the minimal standard model as the source of the asymmetry, but which is easily arranged with an extended Higgs sector. The baryon-number violating rates themselves are not exactly known, and they must be pushed to their theoretical limits. A more exact determination of these rates is needed before a definitive answer can be given. Finally, the phase transition must be at least weakly first order. Such phase transitions are accompanied by the formation and expansion of bubbles of true vacuum within the false vacuum, much like the boiling of water. As the bubbles expand, they provide a departure from thermal equilibrium, otherwise the dynamics will adjust the net baryon number to zero. The bubble expansion also provides a biasing that creates an asymmetry on the bubbles surface. Under optimal conditions, the observed asymmetry can just be produced. 31 refs., 10 figs.
Anomalous facial nerve canal with cochlear malformations.
Romo, L V; Curtin, H D
2001-05-01
Anteromedial "migration" of the first segment of the facial nerve canal has been previously identified in a patient with a non-Mondini-type cochlear malformation. In this study, several patients with the same facial nerve canal anomaly were reviewed to assess for the association and type of cochlear malformation. CT scans of the temporal bone of 15 patients with anteromedial migration of the first segment of the facial nerve canal were collected from routine departmental examinations. In seven patients, the anomalous course was bilateral, for a total of 22 cases. The migration was graded relative to normal as either mild/moderate or pronounced. The cochlea in each of these cases was examined for the presence and size of the basilar, second, and apical turns. The turns were either absent, small, normal, or enlarged. The CT scans of five patients with eight Mondini malformations were examined for comparison. The degree of the facial nerve migration was pronounced in nine cases and mild/moderate in 13. All 22 of these cases had associated cochlear abnormalities of the non-Mondini variety. These included common cavity anomalies with lack of definition between the cochlea and vestibule (five cases), cochleae with enlarged basilar turns and absent second or third turns (five cases), and cochleae with small or normal basilar turns with small or absent second or third turns (12 cases). None of the patients with Mondini-type cochlear malformations had anteromedial migration of the facial nerve canal. Anteromedial migration of the facial nerve canal occurs in association with some cochlear malformations. It did not occur in association with the Mondini malformations. A cochlea with a Mondini malformation, being similar in size to a normal cochlea, may physically prohibit such a deviation in course.
Anomalous baryogenesis at the weak scale
International Nuclear Information System (INIS)
Singleton, R.L. Jr.
1991-06-01
One of the fundamental constants of nature is the baryon asymmetry of the universe -- the ratio of the number of baryons to the entropy. This constant is about 10 -11 . In baryon- number conserving theories, this was just an initial condition. With the advent of the grand unified theories (GUTs), baryon number is no longer conserved, and this asymmetry can be generated dynamically. Unfortunately, however, there are reasons for preferring another mechanism. For example, GUTs predict proton decay which, after extensive searches, has not been found. An alternative place to look for baryogenesis is the electroweak phase transition, described by the standard model, which posses all the necessary ingredients for baryogenesis. Anomalous baryon-number violation in weak interactions becomes large at high temperatures, which offers the prospect of creating the asymmetry with the standard model or minimal extensions. This can just barely be done if certain conditions are fulfilled. CP violation must be large, which rules out the minimal standard model as the source of the asymmetry, but which is easily arranged with an extended Higgs sector. The baryon-number violating rates themselves are not exactly known, and they must be pushed to their theoretical limits. A more exact determination of these rates is needed before a definitive answer can be given. Finally, the phase transition must be at least weakly first order. Such phase transitions are accompanied by the formation and expansion of bubbles of true vacuum within the false vacuum, much like the boiling of water. As the bubbles expand, they provide a departure from thermal equilibrium, otherwise the dynamics will adjust the net baryon number to zero. The bubble expansion also provides a biasing that creates an asymmetry on the bubbles surface. Under optimal conditions, the observed asymmetry can just be produced. 31 refs., 10 figs
The peak in anomalous magnetic viscosity
International Nuclear Information System (INIS)
Collocott, S.J.; Watterson, P.A.; Tan, X.H.; Xu, H.
2014-01-01
Anomalous magnetic viscosity, where the magnetization as a function of time exhibits non-monotonic behaviour, being seen to increase, reach a peak, and then decrease, is observed on recoil lines in bulk amorphous ferromagnets, for certain magnetic prehistories. A simple geometrical approach based on the motion of the state line on the Preisach plane gives a theoretical framework for interpreting non-monotonic behaviour and explains the origin of the peak. This approach gives an expression for the time taken to reach the peak as a function of the applied (or holding) field. The theory is applied to experimental data for bulk amorphous ferromagnet alloys of composition Nd 60−x Fe 30 Al 10 Dy x , x = 0, 1, 2, 3 and 4, and it gives a reasonable description of the observed behaviour. The role played by other key magnetic parameters, such as the intrinsic coercivity and fluctuation field, is also discussed. When the non-monotonic behaviour of the magnetization of a number of alloys is viewed in the context of the model, features of universal behaviour emerge, that are independent of alloy composition. - Highlights: • Development of a simple geometrical model based on the Preisach model which gives a complete explanation of the peak in the magnetic viscosity. • Geometrical approach is extended by considering equations that govern the motion of the state line. • The model is used to deduce the relationship between the holding field and the time it takes to reach the peak. • The model is tested with experimental results for a range of Nd–Fe–Al–Dy bulk amorphous ferromagnets. • There is good agreement between the model and the experimental data
Anomalous xenon in zone 13 Okelobondo
International Nuclear Information System (INIS)
Meshik, A.P.; Kehm, K.; Hohenberg, C.M.
2000-01-01
In situ laser extraction techniques were applied for the study of heavy noble gases in a polished section of Zone 13 from the natural nuclear reactor in Okelobondo. Three main mineral phases were identified in this polished section using SEM-EDX. The Xe and Kr isotopic structures were determined by multiple measurements in each of these phases. Twenty-four isotopic analyses of the gases extracted from two different U-rich phases revealed nearly normal fission spectra. All 9 analyses of a U-free phase, consisting mainly of alumophosphates, demonstrated an unusual isotopic composition ( 136 Xe/ 134 Xe/ 132 Xe/ 131 Xe/ 130 Xe 129 Xe/ 128 Xe = 1/1.25/1.73/0.89/0.0045/0.274/0) with concentrations ranging up to 10 -2 cm 3 STP/g. This is the highest Xe concentration ever measured in a natural material. Kr was also anomalous, although to a lesser extent. These results confirm the presence of Chemical Fractionation of Fission Xe (CFF-Xe) in the Okelobondo alumophosphates. CFF-Xe is a decay product of intermediate fission fragments that have migrated out of the U-rich host phases into adjacent U-free minerals. The CFF-Xe spectra in the alumophosphates are also accompanied by 130 Xe excesses, which are attributed to neutron capture on fissiogenic 129 I that apparently migrated out of the nearby U-rich minerals. The 130 Xe/ 129 Xe ratio allows one to estimate the thermal equivalent neutron dose of 1.1 x 10 21 n/cm 2 . The presence of an unknown fission component remarkably similar in composition to CFF-Xe can be inferred from the atmospheric and terrestrial data. This leads one to the hypothesis that the CFF process has operated on a global scale on the Earth
Fused silica thermal conductivity dispersion at high temperature
International Nuclear Information System (INIS)
Bouchut, P.; Decruppe, D.; Delrive, L.
2004-01-01
A continuous CO 2 laser is focused to locally anneal small fused silica spots. A noncontact radiometry diagnostic enables us to follow surface temperature variation that occurs from site to site. A 'steady state' dispersion of surface temperature is observed across our sample. We show that nonhomogeneous silica thermal conductivity, above 1000 K is responsible for this temperature dispersion
Sen, Supratim; Rao, Suresh G; Kulkarni, Snehal
2016-06-01
We describe the cases of two patients with tetralogy of Fallot, aged 4 years and 8 months, who were incidentally detected to have concomitant anomalous left coronary artery from pulmonary artery and total anomalous pulmonary venous connection, respectively, on preoperative imaging. They underwent surgical correction with good mid-term outcomes. In this study, we discuss the embryological basis, physiological effects, and review the literature of these two unusual associations. Awareness of these rare associations will avoid missed diagnoses and consequent surgical surprises.
Directory of Open Access Journals (Sweden)
Oswaldo Paulo Forattini
1971-12-01
Full Text Available São apresentados os resultados de investigação destinada a estabelecer o quadro de distribuição de Triatoma sordida e Rhodnius neglectus em áreas com ecótopos naturais e artificiais. Essa distribuição revelou-se do tipo agrupado ou contagiante, dirigida uniformemente para casas e anexos por parte do primeiro, e para palmeiras por parte do segundo. Em áreas de vegetação mais densa, do tipo cerrado, a densidade é praticamente nula ou muito baixa, admitindo-se que isso deva correr por conta da competição. As modificações introduzidas pelo homem tendem a anular êsse fator, além de, as suas habitações, se transformarem em ecótopos que atraem a população de T. sordida. Êsse fato, aliado à eliminação local do T. infestans, parece explicar a tendência invasiva daquele triatomíneo. Evidenciou-se também a persistência da infecção pelo Trypanosoma cruzi em triatomíneos e vertebrados domiciliados, o que representa potencial para o incremento da transmissão.A local distribution pattern of Triatoma sordida and Rhodnius neglectus is described after an intensive investigation on natural and artificial ecotopes. The work was carried in a region at north of the State of São Paulo, Brazil. Measures of dispersion pattern were made by the Morisita's indices showing contagious distributions to both bugs. The T. sordida population was clumped at houses and surrounding dwellings, while R. neglectus presented the same aspect but relater to palm trees. The first bug showed ubiquity patter including palms, dry trees and fences. These last two situations are not favourable for obtaining blood meals, who are much more easy obtained at human dwellings. By other side, the investigations at areas with more dense vegetation like bush, resulted in very few T. sordida and none R. neglectus, probably owing of other populations competition as predators reduvids bugs, found there with great density. So it seems logic remove that competition and
Dispersive analysis of the pion transition form factor
Hoferichter, M.; Kubis, B.; Leupold, S.; Niecknig, F.; Schneider, S. P.
2014-11-01
We analyze the pion transition form factor using dispersion theory. We calculate the singly-virtual form factor in the time-like region based on data for the cross section, generalizing previous studies on decays and scattering, and verify our result by comparing to data. We perform the analytic continuation to the space-like region, predicting the poorly-constrained space-like transition form factor below , and extract the slope of the form factor at vanishing momentum transfer . We derive the dispersive formalism necessary for the extension of these results to the doubly-virtual case, as required for the pion-pole contribution to hadronic light-by-light scattering in the anomalous magnetic moment of the muon.
Can I solve my structure by SAD phasing? Anomalous signal in SAD phasing.
Terwilliger, Thomas C; Bunkóczi, Gábor; Hung, Li Wei; Zwart, Peter H; Smith, Janet L; Akey, David L; Adams, Paul D
2016-03-01
A key challenge in the SAD phasing method is solving a structure when the anomalous signal-to-noise ratio is low. A simple theoretical framework for describing measurements of anomalous differences and the resulting useful anomalous correlation and anomalous signal in a SAD experiment is presented. Here, the useful anomalous correlation is defined as the correlation of anomalous differences with ideal anomalous differences from the anomalous substructure. The useful anomalous correlation reflects the accuracy of the data and the absence of minor sites. The useful anomalous correlation also reflects the information available for estimating crystallographic phases once the substructure has been determined. In contrast, the anomalous signal (the peak height in a model-phased anomalous difference Fourier at the coordinates of atoms in the anomalous substructure) reflects the information available about each site in the substructure and is related to the ability to find the substructure. A theoretical analysis shows that the expected value of the anomalous signal is the product of the useful anomalous correlation, the square root of the ratio of the number of unique reflections in the data set to the number of sites in the substructure, and a function that decreases with increasing values of the atomic displacement factor for the atoms in the substructure. This means that the ability to find the substructure in a SAD experiment is increased by high data quality and by a high ratio of reflections to sites in the substructure, and is decreased by high atomic displacement factors for the substructure.
Asymmetry in species regional dispersal ability and the neutral theory.
Directory of Open Access Journals (Sweden)
Jiajia Liu
Full Text Available The neutral assumption that individuals of either the same or different species share exactly the same birth, death, migration, and speciation probabilities is fundamental yet controversial to the neutral theory. Several theoretical studies have demonstrated that a slight difference in species per capita birth or death rates can have a profound consequence on species coexistence and community structure. Whether asymmetry in migration, a vital demographic parameter in the neutral model, plays an important role in community assembly still remains unknown. In this paper, we relaxed the ecological equivalence assumption of the neutral model by introducing differences into species regional dispersal ability. We investigated the effect of asymmetric dispersal on the neutral local community structure. We found that per capita asymmetric dispersal among species could reduce species richness of the local community and result in deviations of species abundance distributions from those predicted by the neutral model. But the effect was moderate compared with that of asymmetries in birth or death rates, unless very large asymmetries in dispersal were assumed. A large difference in species dispersal ability, if there is, can overwhelm the role of random drift and make local community dynamics deterministic. In this case, species with higher regional dispersal abilities tended to dominate in the local community. However, the species abundance distribution of the local community under asymmetric dispersal could be well fitted by the neutral model, but the neutral model generally underestimated the fundamental biodiversity number but overestimated the migration rate in such communities.
DEFF Research Database (Denmark)
2014-01-01
The last decades have witnessed a significant shift in policy competences away from central governments in Europe. The reallocation of competences spans over three dimensions: upwards; sideways; and downwards. This collection takes the dispersion of powers as a starting point and seeks to assess...... how the actors involved cope with the new configurations. In this introduction, we discuss the conceptualization of power dispersion and highlight the ways in which the contributions add to this research agenda. We then outline some general conclusions and end by indicating future avenues of research....... Taken together, the collection contributes some answers to the challenge of defining and measuring – in a comparative way – the control and co-ordination mechanisms which power dispersion generates. It also explores the tension between political actors' quest for autonomy and the acknowledgement...
Light-by-light scattering and muon's anomalous magnetic moment
International Nuclear Information System (INIS)
Pauk, Vladyslav
2014-01-01
phenomenological implications of these results for mesons in both the light-quark sector and the charm-quark sector. In the second part of this thesis we develop the formalism to provide an improved estimate for the hadronic light-by-light (HLbL) correction to the muon's anomalous magnetic moment a μ , by considering single meson contributions beyond the leading pseudo-scalar mesons. This is motivated by the present 3σ deviation between the measurement of a μ and its estimate in the Standard Model. Furthermore, a forthcoming new experiment at Fermilab aims to improve the experimental precision by a factor of 4 which also requires a similar theoretical improvement. We incorporate available experimental input as well as constraints from light-by-light scattering sum rules to estimate the effects of axial-vector, scalar, and tensor mesons. We give numerical evaluations for the HLbL contribution of these states to a μ . The presented formalism allows to further improve on these estimates, once new data for such meson states will become available. In the last part of this work, we present a new dispersion formalism developed for the HLbL contribution to a μ and test the formalism for the case of scalar field theory. The new framework opens a unique possibility for a consistent incorporation of data from e + e - colliders for single- as well as multi-meson contributions. Furthermore, it allows to systematically control the HLbL uncertainty in the a μ which is a crucial step in searches of new physics using this precision quantity.
The Anomalous Process γπ → ππ and its Impact on the π0 Transition Form Factor
Kubis, Bastian
2014-12-01
The process γπ → ππ, in the limit of vanishing photon and pion energies, is determined by the chiral anomaly. This reaction can be investigated experimentally using Primakoff reactions, as currently done at COMPASS. We derive a dispersive representation that allows one to extract the chiral anomaly from cross-section measurements up to 1 GeV, where effects of the ρ resonance are included model-independently via the ππ P-wave phase shift. We discuss how this amplitude serves as an important input to a dispersion-theoretical analysis of the π0 transition form factor, which in turn is a vital ingredient to the hadronic light-by-light contribution to the anomalous magnetic moment of the muon.
Franssens, G; De Maziére, M; Fonteyn, D
2000-08-20
A new derivation is presented for the analytical inversion of aerosol spectral extinction data to size distributions. It is based on the complex analytic extension of the anomalous diffraction approximation (ADA). We derive inverse formulas that are applicable to homogeneous nonabsorbing and absorbing spherical particles. Our method simplifies, generalizes, and unifies a number of results obtained previously in the literature. In particular, we clarify the connection between the ADA transform and the Fourier and Laplace transforms. Also, the effect of the particle refractive-index dispersion on the inversion is examined. It is shown that, when Lorentz's model is used for this dispersion, the continuous ADA inverse transform is mathematically well posed, whereas with a constant refractive index it is ill posed. Further, a condition is given, in terms of Lorentz parameters, for which the continuous inverse operator does not amplify the error.
Streamlined Modeling for Characterizing Spacecraft Anomalous Behavior
Klem, B.; Swann, D.
2011-09-01
Anomalous behavior of on-orbit spacecraft can often be detected using passive, remote sensors which measure electro-optical signatures that vary in time and spectral content. Analysts responsible for assessing spacecraft operational status and detecting detrimental anomalies using non-resolved imaging sensors are often presented with various sensing and identification issues. Modeling and measuring spacecraft self emission and reflected radiant intensity when the radiation patterns exhibit a time varying reflective glint superimposed on an underlying diffuse signal contribute to assessment of spacecraft behavior in two ways: (1) providing information on body component orientation and attitude; and, (2) detecting changes in surface material properties due to the space environment. Simple convex and cube-shaped spacecraft, designed to operate without protruding solar panel appendages, may require an enhanced level of preflight characterization to support interpretation of the various physical effects observed during on-orbit monitoring. This paper describes selected portions of the signature database generated using streamlined signature modeling and simulations of basic geometry shapes apparent to non-imaging sensors. With this database, summarization of key observable features for such shapes as spheres, cylinders, flat plates, cones, and cubes in specific spectral bands that include the visible, mid wave, and long wave infrared provide the analyst with input to the decision process algorithms contained in the overall sensing and identification architectures. The models typically utilize baseline materials such as Kapton, paints, aluminum surface end plates, and radiators, along with solar cell representations covering the cylindrical and side portions of the spacecraft. Multiple space and ground-based sensors are assumed to be located at key locations to describe the comprehensive multi-viewing aspect scenarios that can result in significant specular reflection
Introduction to nonlinear dispersive equations
Linares, Felipe
2015-01-01
This textbook introduces the well-posedness theory for initial-value problems of nonlinear, dispersive partial differential equations, with special focus on two key models, the Korteweg–de Vries equation and the nonlinear Schrödinger equation. A concise and self-contained treatment of background material (the Fourier transform, interpolation theory, Sobolev spaces, and the linear Schrödinger equation) prepares the reader to understand the main topics covered: the initial-value problem for the nonlinear Schrödinger equation and the generalized Korteweg–de Vries equation, properties of their solutions, and a survey of general classes of nonlinear dispersive equations of physical and mathematical significance. Each chapter ends with an expert account of recent developments and open problems, as well as exercises. The final chapter gives a detailed exposition of local well-posedness for the nonlinear Schrödinger equation, taking the reader to the forefront of recent research. The second edition of Introdu...
Towards a dispersive determination of the η and η' transition form factors
Kubis, Bastian
2018-01-01
We discuss status and prospects of a dispersive analysis of the η and η' transition form factors. Particular focus is put on the various pieces of experimental information that serve as input to such a calculation. These can help improve on the precision of an evaluation of the η and η' pole contributions to hadronic light-by-light scattering in the anomalous magnetic moment of the muon.
Towards a dispersive determination of the η and η′ transition form factors
Directory of Open Access Journals (Sweden)
Kubis Bastian
2018-01-01
Full Text Available We discuss status and prospects of a dispersive analysis of the η and η′ transition form factors. Particular focus is put on the various pieces of experimental information that serve as input to such a calculation. These can help improve on the precision of an evaluation of the η and η′ pole contributions to hadronic light-by-light scattering in the anomalous magnetic moment of the muon.
ANOMALOUS MICROWAVE EMISSION IN H ii REGIONS: IS IT REALLY ANOMALOUS? THE CASE OF RCW 49
Energy Technology Data Exchange (ETDEWEB)
Paladini, Roberta [Infrared Processing Analysis Center, California Institute of Technology, 770 South Wilson Ave., Pasadena, CA 91125 (United States); Ingallinera, Adriano; Agliozzo, Claudia; Umana, Grazia; Trigilio, Corrado [Osservatorio Astrofisico di Catania, Via S. Sofia 78, I-95123 Catania Italy (Italy); Tibbs, Christopher T. [Scientific Support Office, Directorate of Science and Robotic Exploration,European Space Research and Technology Centre (ESA/ESTEC), Keplerlaan 1, 2201 AZ, Noordwijk (Netherlands); Noriega-Crespo, Alberto [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Dickinson, Clive [Jodrell Bank Centre for Astrophysics, Alan Turing Building, School of Physics and Astronomy, The University of Manchester, Oxford Road, Manchester M13 9PL (United Kingdom)
2015-11-01
The detection of an excess of emission at microwave frequencies with respect to the predicted free–free emission has been reported for several Galactic H ii regions. Here, we investigate the case of RCW 49, for which the Cosmic Background Imager tentatively (∼3σ) detected Anomalous Microwave Emission (AME) at 31 GHz on angular scales of 7′. Using the Australia Telescope Compact Array, we carried out a multi-frequency (5, 19, and 34 GHz) continuum study of the region, complemented by observations of the H109α radio recombination line. The analysis shows that: (1) the spatial correlation between the microwave and IR emission persists on angular scales from 3.′4 to 0.″4, although the degree of the correlation slightly decreases at higher frequencies and on smaller angular scales; (2) the spectral indices between 1.4 and 5 GHz are globally in agreement with optically thin free–free emission, however, ∼30% of these are positive and much greater than −0.1, consistent with a stellar wind scenario; and (3) no major evidence for inverted free–free radiation is found, indicating that this is likely not the cause of the Anomalous Emission in RCW 49. Although our results cannot rule out the spinning dust hypothesis to explain the tentative detection of AME in RCW 49, they emphasize the complexity of astronomical sources that are very well known and studied, such as H ii regions, and suggest that, at least in these objects, the reported excess of emission might be ascribed to alternative mechanisms such as stellar winds and shocks.
DEFF Research Database (Denmark)
Li, Jiying; Jensen, Thomas Bagger Stibius; Andersen, Niels Hessel
2009-01-01
) indicates the instability of the Ising-type ground state that eventually evolves into the incommensurate phase as the temperature is raised. The pure LiNiPO4 system (x=0) undergoes a first-order magnetic phase transition from a long-range incommensurate phase to an antiferromagnetic (AFM) ground state at TN......Elastic and inelastic neutron-scattering studies of Li(Ni1−xFex)PO4 single crystals reveal anomalous spin-wave dispersions along the crystallographic direction parallel to the characteristic wave vector of the magnetic incommensurate phase. The anomalous spin-wave dispersion (magnetic soft mode......=20.8 K. At 20% Fe concentrations, although the AFM ground state is to a large extent preserved as that of the pure system, the phase transition is second order, and the incommensurate phase is completely suppressed. Analysis of the dispersion curves using a Heisenberg spin Hamiltonian that includes...
Systematic Serendipity: A Method to Discover the Anomalous
Giles, Daniel; Walkowicz, Lucianne
2018-01-01
One of the challenges in the era of big data astronomical surveys is identifying anomalous data, data that exhibits as-of-yet unobserved behavior. These data may result from systematic errors, extreme (or rare) forms of known phenomena, or, most interestingly, truly novel phenomena that has historically required a trained eye and often fortuitous circumstance to identify. We describe a method that uses machine clustering techniques to discover anomalous data in Kepler lightcurves, as a step towards systematizing the detection of novel phenomena in the era of LSST. As a proof of concept, we apply our anomaly detection method to Kepler data including Boyajian's Star (KIC 8462852). We examine quarters 4, 8, 11, and 16 of the Kepler data which contain Boyajian’s Star acting normally (quarters 4 and 11) and anomalously (quarters 8 and 16). We demonstrate that our method is capable of identifying Boyajian’s Star’s anomalous behavior in quarters of interest, and we further identify other anomalous light curves that exhibit a range of interesting variability.
Employment effects of spatial dispersal of refugees
DEFF Research Database (Denmark)
Damm, Anna Piil; Rosholm, Michael
2010-01-01
Refugees subjected to a spatial dispersal tend to be assigned to a location outside the immigrant-dense cities. We argue that such locations are associated with low place utility. Our partial equilibrium search model with simultaneous job and residential location search predicts that the reservat......Refugees subjected to a spatial dispersal tend to be assigned to a location outside the immigrant-dense cities. We argue that such locations are associated with low place utility. Our partial equilibrium search model with simultaneous job and residential location search predicts...... that the reservation wage for local jobs decreases with place utility. We test the theoretical prediction by estimating the effects of characteristics of the location of assignment on the transition rate into the first job. Our sample is male refugees aged 30-59 who were subjected to the Danish spatial dispersal...
Neoclassical and anomalous transport in axisymmetric toroidal plasmas with electrostatic turbulence
International Nuclear Information System (INIS)
Sugama, H.; Horton, W.
1995-05-01
Neoclassical and anomalous transport fluxes are determined for axisymmetric toroidal plasmas with weak electrostatic fluctuations. The neoclassical and anomalous fluxes are defined based on the ensemble-averaged kinetic equation with the statistically averaged nonlinear term. The anomalous forces derived from that quasilinear term induce the anomalous particle and heat fluxes. The neoclassical banana-plateau particle and heat fluxes and the bootstrap current are also affected by the fluctuations through the parallel anomalous forces and the modified parallel viscosities. The quasilinear term, the anomalous forces, and the anomalous particle and heat fluxes are evaluated from the fluctuating part of the drift kinetic equation. The averaged drift kinetic equation with the quasilinear term is solved for the plateau regime to derive the parallel viscosities modified by the fluctuations. The entropy production rate due to the anomalous transport processes is formulated and used to identify conjugate pairs of the anomalous fluxes and forces, which are connected by the matrix with the Onsager symmetry. (author)
Interface, a dispersed architecture
Vissers, C.A.
1976-01-01
Past and current specification techniques use timing diagrams and written text to describe the phenomenology of an interface. This paper treats an interface as the architecture of a number of processes, which are dispersed over the related system parts and the message path. This approach yields a
Psychorheology of food dispersions
Czech Academy of Sciences Publication Activity Database
Štern, Petr; Panovská, Z.; Pokorný, J.
2010-01-01
Roč. 58, č. 1 (2010), s. 29-35 ISSN 0042-790X R&D Projects: GA AV ČR IAA2060404 Institutional research plan: CEZ:AV0Z20600510 Keywords : psychorheology * food dispersions * tomato ketchup * rheology * sensory analysis Subject RIV: BK - Fluid Dynamics Impact factor: 0.553, year: 2010
Reddy, Ramana; Kumar, Sanjeev
2007-12-01
In this paper, we show through simulations that when sticky particles are broken continually, particles are dispersed into fine dust only if they are present in a narrow range of volume fractions. The upper limit of this range is 0.20 in the 2D and 0.10 in the 3D space. An increase in the dimensionality of space reduces the upper limit nearly by a factor of two. This scaling holds for dispersal of particles in hyperdimensional space of dimensions up to ten, the maximum dimension studied in this work. The maximum values of volume fractions obtained are significantly lower than those required for close packing and random packing of discs in 2D and spheres in 3D space. These values are also smaller than those required for critical phenomena of cluster percolation. The results obtained are attributed to merger cascades of sticky particles, triggered by breakup events. A simple theory that incorporates this cascade is developed to quantitatively explain the observed scaling of the upper limit with the dimensionality of space. The theory also captures the dynamics of the dispersal process in the corresponding range of particle volume fractions. The theory suggests that cascades of order one and two predominantly decide the upper limit for complete dispersal of particles.
Humans as long-distance dispersers of rural plant communities.
Directory of Open Access Journals (Sweden)
Alistair G Auffret
Full Text Available Humans are known for their capacity to disperse organisms long distances. Long-distance dispersal can be important for species threatened by habitat destruction, but research into human-mediated dispersal is often focused upon few and/or invasive species. Here we use citizen science to identify the capacity for humans to disperse seeds on their clothes and footwear from a known species pool in a valuable habitat, allowing for an assessment of the fraction and types of species dispersed by humans in an alternative context. We collected material from volunteers cutting 48 species-rich meadows throughout Sweden. We counted 24,354 seeds of 197 species, representing 34% of the available species pool, including several rare and protected species. However, 71 species (36% are considered invasive elsewhere in the world. Trait analysis showed that seeds with hooks or other appendages were more likely to be dispersed by humans, as well as those with a persistent seed bank. More activity in a meadow resulted in more dispersal, both in terms of species and representation of the source communities. Average potential dispersal distances were measured at 13 km. We consider humans capable seed dispersers, transporting a significant proportion of the plant communities in which they are active, just like more traditional vectors such as livestock. When rural populations were larger, people might have been regular and effective seed dispersers, and the net rural-urban migration resulting in a reduction in humans in the landscape may have exacerbated the dispersal failure evident in declining plant populations today. With the fragmentation of habitat and changes in land use resulting from agricultural change, and the increased mobility of humans worldwide, the dispersal role of humans may have shifted from providers of regular local and landscape dispersal to providers of much rarer long-distance and regional dispersal, and international invasion.
Quantum phase transitions and anomalous Hall effect in a pyrochlore Kondo lattice
Grefe, Sarah; Ding, Wenxin; Si, Qimiao
The metallic variant of the pyrochlore iridates Pr2Ir2O7 has shown characteristics of a possible chiral spin liquid state [PRL 96 087204 (2006), PRL 98, 057203 (2007), Nature 463, 210 (2010)] and quantum criticality [Nat. Mater. 13, 356 (2014)]. An important question surrounding the significant anomalous Hall response observed in Pr2Ir2O7 is the nature of the f-electron local moments, including their Kondo coupling with the conduction d-electrons. The heavy effective mass and related thermodynamic characteristics indicate the involvement of the Kondo effect in this system's electronic properties. In this work, we study the effects of Kondo coupling on candidate time-reversal-symmetry-breaking spin liquid states on the pyrochlore lattice. Representing the f-moments as slave fermions Kondo-coupled to conduction electrons, we study the competition between Kondo-singlet formation and chiral spin correlations and determine the zero-temperature phase diagram. We derive an effective chiral interaction between the local moments and the conduction electrons and calculate the anomalous Hall response across the quantum phase transition from the Kondo destroyed phase to the Kondo screened phase. We discuss our results' implications for Pr2Ir2O7 and related frustrated Kondo-lattice systems.
Quantum phase transitions and anomalous Hall effect in frustrated Kondo lattices
Paschen, Silke; Grefe, Sarah Elaine; Ding, Wenxin; Si, Qimiao
Among the pyrochlore iridates, the metallic compound Pr2 Ir2O7 (Pr-227) has shown characteristics of a possible chiral spin liquid state and quantum criticality. An important question surrounding the significant anomalous Hall response observed in Pr-227 is the nature of the f-electron local moments, including their Kondo coupling with the conduction d-electrons. The heavy effective mass and related thermodynamic characteristics indicate the involvement of the Kondo effect in this system's electronic properties. In this work, we study the effects of Kondo coupling on candidate time-reversal-symmetry-breaking spin liquid states on frustrated lattices. Representing the f-moments as slave fermions Kondo-coupled to conduction electrons, we study the competition between Kondo-singlet formation and chiral spin correlations. We derive an effective chiral interaction between the local moments and the conduction electrons and calculate the anomalous Hall response across the quantum phase transition from the Kondo destroyed phase to the Kondo screened phase. We discuss our results' implications for Pr-227 and related frustrated Kondo-lattice systems.
An analysis of superluminal propagation becoming subluminal in highly dispersive media
Nanda, L.
2018-05-01
In this article the time-moments of the Poynting vector associated with an electromagnetic pulse are used to characterize the traversal time and the pulse width as the pulse propagates through highly dispersive media. The behaviour of these quantities with propagation distance is analyzed in two physical cases: Lorentz absorptive medium, and Raman gain doublet amplifying medium. It is found that the superluminal pulse propagation in these two cases with anomalous dispersion is always accompanied by pulse compression and eventually the pulse becomes subluminal with increasing distance of propagation.
A variable-order fractal derivative model for anomalous diffusion
Directory of Open Access Journals (Sweden)
Liu Xiaoting
2017-01-01
Full Text Available This paper pays attention to develop a variable-order fractal derivative model for anomalous diffusion. Previous investigations have indicated that the medium structure, fractal dimension or porosity may change with time or space during solute transport processes, results in time or spatial dependent anomalous diffusion phenomena. Hereby, this study makes an attempt to introduce a variable-order fractal derivative diffusion model, in which the index of fractal derivative depends on temporal moment or spatial position, to characterize the above mentioned anomalous diffusion (or transport processes. Compared with other models, the main advantages in description and the physical explanation of new model are explored by numerical simulation. Further discussions on the dissimilitude such as computational efficiency, diffusion behavior and heavy tail phenomena of the new model and variable-order fractional derivative model are also offered.
Anomalous Hall effect and Nernst effect in itinerant ferromagnets
International Nuclear Information System (INIS)
Asamitsu, A.; Miyasato, T.; Abe, N.; Fujii, T.; Onose, Y.; Onoda, S.; Nagaosa, N.; Tokura, Y.
2007-01-01
Anomalous Hall effect (AHE) and anomalous Nernst effect (ANE) in many ferromagnetic metals including pure metals, oxides, and calcogenides, are studied to obtain unified understandings of their origins. We show the universal behavior of anomalous Hall conductivity σ xy as a function of longitudinal conductivity σ xx over six orders of magnitude, which is well reproduced by rigorous unified theory assuming both intrinsic and extrinsic contributions to the AHE. ANE is closely related with AHE and gives us further information about the electronic state in the ground state of ferromagnets. The temperature dependence of transverse Peltier coefficient α xy shows almost similar behavior among various ferromagnets and this behavior is expected from a conventional Boltzmann transport theory
The anomalous self-diffusion in α-Zr
International Nuclear Information System (INIS)
Hood, G.M.
1985-01-01
In a very recent publication, Horvath, Dyment and Mehrer, henceforth HDM, presented measurements of the self-diffusion coefficient Dsub(m) 0 for α-Zr as a function of temperature. The results of that study, done on a single crystal sample, were anomalous in the sense that a plot of log Dsub(m) 0 vs. 1/T(K -1 ) was not only non-linear, but exhibited two regions of downward curvature with increasing 1/T. HDM indicated that they were unable to see any explanation of their anomalous self-diffusion results. It is the purpose of this letter to indicate a means whereby these anomalous results may be ''explained'' and to suggest some experiments which might be undertaken to test the proposal. (orig./RK)
Anomalous high-frequency resistivity of a plasma
International Nuclear Information System (INIS)
Kruer, W.L.; Dawson, J.M.
1971-06-01
In one- and two-dimensional computer simulations we investigate anomalous high-frequency resistivity in a plasma driven by a large electric field oscillating near the electron plasma frequency. The large field excites the oscillating two-stream and the ion-acoustic decay instabilities in agreement with the linear theory. When the ion and electron fluctuations saturate, a strong anomalous heating of the plasma sets in. This strong heating is due to an efficient coupling of the externally imposed large electric field to the plasma by ion fluctuations. We determine the anomalous collision frequency and the saturation fluctuation amplitudes as a function of the external field amplitude and frequency, and the electron-ion mass ratio. A simple nonlinear theory gives results in reasonable agreement with simulations. 24 refs., 10 figs
Gauge invariance and anomalous theories at finite fermionic density
International Nuclear Information System (INIS)
Roberge, A.
1990-01-01
We investigate the issue of stability of anomalous matter at finite fermionic density using a two-dimensional toy model. In particular, we pay careful attention to the issue of gauge invariance. We find that, contrary to some recent claims, the effective free energy (obtained by integrating out the fermions) cannot be obtained by the simple inclusion of a Chern-Simons term multiplying the fermionic chemical potential. We obtain some conditions for stability of anomalous charges when some finite density of conserved charge is present as well as for the neutral case. We also show that, under reasonable conditions, no sphaleron-type solution can exist in the toy model unless the anomalous charge density vanishes. We argue that this could be the case for more realistic models as well
Quantum anomalous Bloch-Siegert shift in Weyl semimetal
Kumar, Upendra; Kumar, Vipin; Enamullah, Setlur, Girish S.
2018-05-01
A periodic exchange of energy between the light field and two level system is known as Rabi oscillations. The Bloch-Siegert shift (BSS) is a shift in Rabi oscillation resonance condition, when the driving field is sufficiently strong. There are new type of oscillations exhibit in Weyl semimetal at far from resonance, known as anomalous Rabi oscillation. In this work, we study the phenomenon of the Bloch-Siegert shift in Weyl semimetal at far from resonance called anomalous Bloch-Siegert shift (ABSS) by purely quantum mechanical treatment and describe it's anisotropic nature. A fully numerical solution of the Floquet-Bloch equations unequivocally establishes the presence of not only anomalous Rabi oscillations in these systems but also their massless character.
Microinstability-based model for anomalous thermal confinement in tokamaks
International Nuclear Information System (INIS)
Tang, W.M.
1986-03-01
This paper deals with the formulation of microinstability-based thermal transport coefficients (chi/sub j/) for the purpose of modelling anomalous energy confinement properties in tokamak plasmas. Attention is primarily focused on ohmically heated discharges and the associated anomalous electron thermal transport. An appropriate expression for chi/sub e/ is developed which is consistent with reasonable global constraints on the current and electron temperature profiles as well as with the key properties of the kinetic instabilities most likely to be present. Comparisons of confinement scaling trends predicted by this model with the empirical ohmic data base indicate quite favorable agreement. The subject of anomalous ion thermal transport and its implications for high density ohmic discharges and for auxiliary-heated plasmas is also addressed
Anomalous Hall effect and Nernst effect in itinerant ferromagnets
International Nuclear Information System (INIS)
Miyasato, T.; Abe, N.; Fujii, T.; Asamitsu, A.; Onose, Y.; Onoda, S.; Nagaosa, N.; Tokura, Y.
2007-01-01
Anomalous Hall effect (AHE) and anomalous Nernst effect (ANE) in many ferromagnetic metals including pure metals, oxides, and chalcogenides, are studied to obtain unified understandings of their origins. We show the universal behavior of anomalous Hall conductivity σ xy as a function of longitudinal conductivity σ xx over six orders of magnitude, which is well reproduced by a recent theory assuming both the intrinsic and extrinsic contributions to the AHE. ANE is closely related with AHE and gives us further information about the electronic state in the ground state of ferromagnets. The temperature dependence of transverse Peltier coefficient α xy shows almost similar behavior among various ferromagnets, and this behavior is expected from a conventional Boltzmann transport theory
ε-iron nitrides: Intrinsic anomalous Hall ferromagnets
Directory of Open Access Journals (Sweden)
Guo-Ke Li
2015-02-01
Full Text Available The anomalous Hall effect in ε-iron nitrides (ε-Fe3-xN, 0 ≤ x ≤ 1 has been systematically investigated taking advantage of the fact that the exchange splitting of ε-Fe3-xN can be continuously tuned through the nitrogen concentration. It has been found that the anomalous Hall conductivity, σ x y A H , is proportional to the saturation magnetization MS, i.e., σ x y A H = S H M S , across significant variations in the saturation magnetization (96–1146 emu/cc. This relationship is in excellent agreement with the intrinsic mechanism as well as with the unified theory of AHE. Our results also demonstrate that the anomalous Hall conductivity is sensitive to the exchange splitting of the band structure.
International Nuclear Information System (INIS)
Kroeger, J
2008-01-01
Three aspects of electron-phonon coupling at metal surfaces are reviewed. One aspect is the Kohn effect, which describes an anomalous dispersion relation of surface phonons due to quasi-one-dimensional nesting of Fermi surface contours. The combination of electron energy loss spectroscopy and angle-resolved photoelectron spectroscopy allows us to unambiguously characterize Kohn anomaly systems. A second aspect is the nonadiabatic damping of adsorbate vibrations. Characteristic spectroscopic line shapes of vibrational modes allow us to estimate the amount of energy transfer between the vibrational mode and electron-hole pairs. Case studies of a Kohn anomaly and nonadiabatic damping are provided by the hydrogen- and deuterium-covered Mo(110) surface. As a third aspect of interaction between electrons and phonons, local heating of a C 60 molecule adsorbed on Cu(100) and in contact with the tip of a scanning tunnelling microscope is covered
Does Environmental Knowledge Inhibit Hominin Dispersal?
Wren, Colin D; Costopoulos, Andre
2015-07-01
We investigated the relationship between the dispersal potential of a hominin population, its local-scale foraging strategies, and the characteristics of the resource environment using an agent-based modeling approach. In previous work we demonstrated that natural selection can favor a relatively low capacity for assessing and predicting the quality of the resource environment, especially when the distribution of resources is highly clustered. That work also suggested that the more knowledge foraging populations had about their environment, the less likely they were to abandon the landscape they know and disperse into novel territory. The present study gives agents new individual and social strategies for learning about their environment. For both individual and social learning, natural selection favors decreased levels of environmental knowledge, particularly in low-heterogeneity environments. Social acquisition of detailed environmental knowledge results in crowding of agents, which reduces available reproductive space and relative fitness. Agents with less environmental knowledge move away from resource clusters and into areas with more space available for reproduction. These results suggest that, rather than being a requirement for successful dispersal, environmental knowledge strengthens the ties to particular locations and significantly reduces the dispersal potential as a result. The evolved level of environmental knowledge in a population depends on the characteristics of the resource environment and affects the dispersal capacity of the population.
Anomalous CO2 Emissions in Different Ecosystems Around the World
Sanchez-Canete, E. P.; Moya Jiménez, M. R.; Kowalski, A. S.; Serrano-Ortiz, P.; López-Ballesteros, A.; Oyonarte, C.; Domingo, F.
2016-12-01
As an important tool for understanding and monitoring ecosystem dynamics at ecosystem level, the eddy covariance (EC) technique allows the assessment of the diurnal and seasonal variation of the net ecosystem exchange (NEE). Despite the high temporal resolution data available, there are still many processes (in addition to photosynthesis and respiration) that, although they are being monitored, have been neglected. Only a few authors have studied anomalous CO2 emissions (non biological), and have related them to soil ventilation, photodegradation or geochemical processes. The aim of this study is: 1) to identify anomalous short term CO2 emissions in different ecosystems distributed around the world, 2) to determine the meteorological variables that are influencing these emissions, and 3) to explore the potential processes that can be involved. We have studied EC data together with other meteorological ancillary variables obtained from the FLUXNET database (version 2015) and have found more than 50 sites with anomalous CO2 emissions in different ecosystem types such as grasslands, croplands or savannas. Data were filtered according to the FLUXNET quality control flags (only data with quality control flag equal to 0 was used) and correlation analysis were performed with NEE and ancillary data. Preliminary results showed strong and highly significant correlations between meteorological variables and anomalous CO2 emissions. Correlation results showed clear differing behaviors between ecosystems types, which could be related to the different processes involved in the anomalous CO2 emissions. We suggest that anomalous CO2 emissions are happening globally and therefore, their contribution to the global net ecosystem carbon balance requires further investigation in order to better understand its drivers.
Splash-cup plants accelerate raindrops to disperse seeds
Amador, Guillermo J.; Yamada, Yasukuni; McCurley, Matthew; Hu, David L.
2013-01-01
The conical flowers of splash-cup plants Chrysosplenium and Mazus catch raindrops opportunistically, exploiting the subsequent splash to disperse their seeds. In this combined experimental and theoretical study, we elucidate their mechanism for maximizing dispersal distance. We fabricate conical plant mimics using three-dimensional printing, and use high-speed video to visualize splash profiles and seed travel distance. Drop impacts that strike the cup off-centre achieve the largest dispersal distances of up to 1 m. Such distances are achieved because splash speeds are three to five times faster than incoming drop speeds, and so faster than the traditionally studied splashes occurring upon horizontal surfaces. This anomalous splash speed is because of the superposition of two components of momentum, one associated with a component of the drop's motion parallel to the splash-cup surface, and the other associated with film spreading induced by impact with the splash-cup. Our model incorporating these effects predicts the observed dispersal distance within 6–18% error. According to our experiments, the optimal cone angle for the splash-cup is 40°, a value consistent with the average of five species of splash-cup plants. This optimal angle arises from the competing effects of velocity amplification and projectile launching angle. PMID:23235266
Dispersion relations in real and virtual Compton scattering
International Nuclear Information System (INIS)
Drechsel, D.; Pasquini, B.; Vanderhaeghen, M.
2003-01-01
A unified presentation is given on the use of dispersion relations in the real and virtual Compton scattering processes off the nucleon. The way in which dispersion relations for Compton scattering amplitudes establish connections between low energy nucleon structure quantities, such as polarizabilities or anomalous magnetic moments, and the nucleon excitation spectrum is reviewed. We discuss various sum rules for forward real and virtual Compton scattering, such as the Gerasimov-Drell-Hearn sum rule and its generalizations, the Burkhardt-Cottingham sum rule, as well as sum rules for forward nucleon polarizabilities, and review their experimental status. Subsequently, we address the general case of real Compton scattering (RCS). Various types of dispersion relations for RCS are presented as tools for extracting nucleon polarizabilities from the RCS data. The information on nucleon polarizabilities gained in this way is reviewed and the nucleon structure information encoded in these quantities is discussed. The dispersion relation formalism is then extended to virtual Compton scattering (VCS). The information on generalized nucleon polarizabilities extracted from recent VCS experiments is described, along with its interpretation in nucleon structure models. As a summary, the physics content of the existing data is discussed and some perspectives for future theoretical and experimental activities in this field are presented
Algebraic isomorphism in two-dimensional anomalous gauge theories
International Nuclear Information System (INIS)
Carvalhaes, C.G.; Belvedere, L.V.; Filho, H.B.; Natividade, C.P.
1997-01-01
The operator solution of the anomalous chiral Schwinger model is discussed on the basis of the general principles of Wightman field theory. Some basic structural properties of the model are analyzed taking a careful control on the Hilbert space associated with the Wightman functions. The isomorphism between gauge noninvariant and gauge invariant descriptions of the anomalous theory is established in terms of the corresponding field algebras. We show that (i) the Θ-vacuum representation and (ii) the suggested equivalence of vector Schwinger model and chiral Schwinger model cannot be established in terms of the intrinsic field algebra. copyright 1997 Academic Press, Inc
Anomalous magnetotransport of a surface electron layer above liquid helium
International Nuclear Information System (INIS)
Grigor'ev, V.N.; Kovdrya, Yu.Z.; Nikolaenko, V.A.; Kirichek, O.I.; Shcherbachenko, R.I.
1991-01-01
The magnetoconductivity σ xx of a surface electron layer above liquid helium has been measured at temperatures between 0.5-1.6 K, for concentrations up to about 4x10 8 cm -2 , in magnetic fields up to 25 kOe. As was observed, σ xx first decreases with lowering temperature, then has a minimum and at T xy , the earlier ascertained anomalous behaviour of the magnetoresistance ρ xx taken into consideration. The calculated dependence of ρ xx on T is in satisfactory agreement with the anomalous dependence ρ xx (T) found earlier by experiment
A classical picture of anomalous effects in a tokamak
International Nuclear Information System (INIS)
Hirano, K.
1984-01-01
It is demonstrated that the atomic collisions between plasma ions and a very small amount of neutral particles remaining in a hot plasma plays a very important role for plasma transports and may be an origin of anomalous effects observed in a tokamak such as the diffusion coefficient independent of the field strength, a rapid plasma density increase during gas puffing and current penetration with anomalously high speed in the start-up phase. The Ohm's law derived by Cowling is used for the analysis. (author)
Five-loop anomalous dimension of twist-two operators
Energy Technology Data Exchange (ETDEWEB)
Lukowski, T. [Institute of Physics, Jagellonian University, ul. Reymonta 4, 30-059 Krakow (Poland); Rej, A. [Blackett Laboratory, Imperial College, London SW7 2AZ (United Kingdom); Velizhanin, V.N., E-mail: velizh@mail.desy.d [Theoretical Physics Department, Petersburg Nuclear Physics Institute, Orlova Roscha, Gatchina, 188300 St. Petersburg (Russian Federation)
2010-05-21
In this article we calculate the five-loop anomalous dimension of twist-two operators in the planar N=4 SYM theory. Firstly, using reciprocity, we derive the contribution of the asymptotic Bethe ansatz. Subsequently, we employ the first finite-size correction for the AdS{sub 5}xS{sup 5} sigma model to determine the wrapping correction. The anomalous dimension found in this way passes all known tests provided by the NLO BFKL equation and double-logarithmic constraints. This result thus furnishes an infinite number of experimental data for testing the veracity of the recently proposed spectral equations for planar AdS/CFT correspondence.
Environmental health impacts of dispersed mineralisation in South Africa
Davies, T. C.; Mundalamo, H. R.
2010-11-01
The crust of South Africa has undergone various episodes and styles of mineralisation, dating as far back as the Archaean. The suite of minerals produced is diverse and includes metals, non-metals and industrial minerals. Since the Pleistocene, substantial quantities of elements, both nutritional and toxic, that were involved in ore forming processes, have been remobilised and redistributed by surficial processes of intense tropical weathering, leaching, eluviation, podsolisation and gleying; and more recently, by mining and related processes, as well as by other urban and industrial activities. As a result of this "dispersion" it is not uncommon to find large tracts of the country containing anomalous trace element contents or deficiencies in essential micro-nutrient elements. Through water and food crops, extremes in trace element variation in soils are transmitted into the food chain, with often undesirable consequences for human and animal health. But the known variations are not as yet adequately documented. Nor is there sufficient knowledge on the implications of these variations for the health of the environment and its ecosystems. Nutrient deficient soils may be the principal causative factor in the devastating endemic osteoarthritic disease that afflicts two-thirds of the women in Maputaland, for instance. The generally low Se status of agricultural soils could represent an important co-factor in the relatively high diffusion rates of HIV-AIDS in the country. The impact of geology on animal health also remains an area of critical concern to both farmers and managers of the hugely important wildlife game reserves. This paper discusses a few known relationships between trace element excess/deficiency stemming originally from mineralisation processes, and the local and regional distribution of diseases in man and animals in South Africa. It is submitted that the challenge for future research in medical geology would lie in an organised effort aimed at
International Nuclear Information System (INIS)
Andreani, M.; Yadigaroglu, G.
1989-12-01
Dispersed flow film boiling is the heat transfer regime that occurs at high void fractions in a heated channel. The way this transfer mode is modelled in the NRC computer codes (RELAP5 and TRAC) and the validity of the assumption and empirical correlations used is discussed. An extensive review of the theoretical and experimental work related with heat transfer to highly dispersed mixtures reveals the basic deficiencies of these models: the investigation refers mostly to the typical conditions of low rate bottom reflooding, since the simulation of this physical situation by the computer codes has often showed poor results. The alternative models that are available in the literature are reviewed, and their merits and limits are highlighted. The modification that could improve the physics of the models implemented in the codes are identified. (author) 13 figs., 123 refs
Working document dispersion models
International Nuclear Information System (INIS)
Dop, H. van
1988-01-01
This report is a summary of the most important results from June 1985 of the collaboration of the RIVM (Dutch National Institute for Public Health and Environment Hygiene) and KNMI (Royal Dutch Meteorologic Institute) on the domain of dispersion models. It contains a short description of the actual SO x /NO x -model. Furthermore it contains recommendations for modifications of some numerical-mathematical aspects and an impulse to a more complete description of chemical processes in the atmosphere and the (wet) deposition process. A separate chapter is devoted to the preparation of meteorologic data which are relevant for dispersion as well as atmospheric chemistry and deposition. This report serves as working document for the final formulation of a acidifying- and oxidant-model. (H.W.). 69 refs.; 51 figs.; 13 tabs.; 3 schemes
Spatially Dispersed Employee Recovery
DEFF Research Database (Denmark)
Hvass, Kristian Anders; Torfadóttir, Embla
2014-01-01
Employee recovery addresses either employee well-being or management's practices in aiding employees in recovering themselves following a service failure. This paper surveys the cabin crew at a small, European, low-cost carrier and investigates employees' perceptions of management practices to aid...... personnel achieve service recovery. Employee recovery within service research often focuses on front-line employees that work in a fixed location, however a contribution to the field is made by investigating the recovery of spatially dispersed personnel, such as operational personnel in the transport sector......, who have a work place away from a fixed or central location and have minimal management contact. Results suggest that the support employees receive from management, such as recognition, information sharing, training, and strategic awareness are all important for spatially dispersed front...
International Nuclear Information System (INIS)
Shaw, T.L.
1974-01-01
One of the tasks of the Sonderforschungsbereich 80 is to study the dispersion of heat discharged into rivers and other bodies of water and to develop methods which permit prediction of detrimental effects caused by the heated discharges. In order to help the SFB 80 to specify this task, Dr. Shaw, lecturer of Civil Engineering at the Bristol University, conducted a literature survey on heat-dispersion studies during the two months which he spent as a visiting research fellow with the SFB 80 at the University of Karlsruhe in the summer of 1973. The following report is the outcome of this survey. It gives Dr. Shaw's assessment of the present state of knowledge - based almost exclusively on literature in the English language - and compares this with the knowledge required by river planners. The apparent discrepancy leads to suggestions for future research. Selected references as well as a representative bibliography can be found at the end of the report. (orig.) [de
International Nuclear Information System (INIS)
Piskorska, E.; Holy, V.; Siebert, M.; Schmidt, Th.; Falta, J.; Yamaguchi, T.; Hommel, D.; Renevier, H.
2006-01-01
The local chemical composition of InGaN quantum dots grown by a MBE method on GaN virtual substrates was investigated by x-ray diffraction anomalous fine-structure method. From the detailed numerical analysis of the data we were able to reconstruct the local neighborhood of Ga atoms at different positions in the dots. Using this approach, we found that the In content increases from 20% at the dot base to 40-50% at the top. (author) [pl
Granular controls on the dispersion of bed load tracers
Jerolmack, D. J.; Martin, R. L.; Phillips, C. B.
2014-12-01
Coarse particles are transported in a river as bed load, i.e., they move in frequent contact with and are supported by the granular bed. This movement is typically intermittent and may be described by a series of steps are rests, the distributions of which determine particle dispersion. Laboratory and field studies of bed load tracer dispersion have reported sub- and super-diffusive behavior, both of which have been successfully reproduced with stochastic transport models. Although researchers have invoked heavy-tailed step lengths as the cause of anomalous dispersion, most observations report thin-tailed distributions. Little attention has been paid to rest periods, and stochastic transport models have not been connected to the underlying mechanics of particle motion. Based on theoretical and experimental evidence, we argue that step lengths are thin-tailed and do not control the longterm dispersion of bed load tracers; they are determined by momentum balance between the fluid and solid. Using laboratory experiments with both marbles and natural sediments, we demonstrate that the rest time distribution is power law, and argue that this distribution controls asymptotic dispersion. Observed rest times far exceed any hydrodynamic timescale. Experiments reveal that rest times of deposited particles are governed by fluctuations in river bed elevation; in particular, the return time for the bed to scour to the base of a deposited particle. Stochastic fluctuations in bed elevation are describable by an Ornstein-Uhlenbeck (mean-reverting random walk) model that contains two parameters, which we show are directly related to the granular shear rate and range of bed elevation fluctuations, respectively. Combining these results with the theory of asymmetric random walks (particles only move downstream), we predict superdiffusive behavior that is in quantitative agreement with our observations of tracer dispersion in a natural river.
Taylor dispersion of nanoparticles
Balog, Sandor; Urban, Dominic A.; Milosevic, Ana M.; Crippa, Federica; Rothen-Rutishauser, Barbara; Petri-Fink, Alke
2017-08-01
The ability to detect and accurately characterize particles is required by many fields of nanotechnology, including materials science, nanotoxicology, and nanomedicine. Among the most relevant physicochemical properties of nanoparticles, size and the related surface-to-volume ratio are fundamental ones. Taylor dispersion combines three independent phenomena to determine particle size: optical extinction, translational diffusion, and sheer-enhanced dispersion of nanoparticles subjected to a steady laminar flow. The interplay of these defines the apparent size. Considering that particles in fact are never truly uniform nor monodisperse, we rigorously address particle polydispersity and calculate the apparent particle size measured by Taylor dispersion analysis. We conducted case studies addressing aqueous suspensions of model particles and large-scale-produced "industrial" particles of both academic and commercial interest of various core materials and sizes, ranging from 15 to 100 nm. A comparison with particle sizes determined by transmission electron microscopy confirms that our approach is model-independent, non-parametric, and of general validity that provides an accurate account of size polydispersity—independently on the shape of the size distribution and without any assumption required a priori.
Anomalous Hall effect in ion-beam sputtered Co2FeAl full Heusler alloy thin films
Husain, Sajid; Kumar, Ankit; Akansel, Serkan; Svedlindh, Peter; Chaudhary, Sujeet
2017-11-01
Investigations of temperature dependent anomalous Hall effect and longitudinal resistivity in Co2FeAl (CFA) thin films grown on Si(1 0 0) at different substrate temperature Ts are reported. The scaling of the anomalous Hall conductivity (AHC) and the associated phenomenological mechanisms (intrinsic and extrinsic) are analyzed vis-à-vis influence of Ts. The intrinsic contribution to AHC is found to be dominating over the extrinsic one. The appearance of a resistivity minimum at low temperature necessitates the inclusion of quantum corrections on account of weak localization and electron-electron scattering effects whose strength reduces with increase in Ts. The study establishes that the optimization of Ts plays an important role in the improvement of atomic ordering which indicates the higher strength of spin-orbit coupling and leads to the dominant intrinsic contribution to AHC in these CFA full Heusler alloy thin films.
Regional zooplankton dispersal provides spatial insurance for ecosystem function.
Symons, Celia C; Arnott, Shelley E
2013-05-01
Changing environmental conditions are affecting diversity and ecosystem function globally. Theory suggests that dispersal from a regional species pool may buffer against changes in local community diversity and ecosystem function after a disturbance through the establishment of functionally redundant tolerant species. The spatial insurance provided by dispersal may decrease through time after environmental change as the local community monopolizes resources and reduces community invasibility. To test for evidence of the spatial insurance hypothesis and to determine the role dispersal timing plays in this response we conducted a field experiment using crustacean zooplankton communities in a subarctic region that is expected to be highly impacted by climate change - Churchill, Canada. Three experiments were conducted where nutrients, salt, and dispersal were manipulated. The three experiments differed in time-since-disturbance that the dispersers were added. We found that coarse measures of diversity (i.e. species richness, evenness, and Shannon-Weiner diversity) were generally resistant to large magnitude disturbances, and that dispersal had the most impact on diversity when dispersers were added shortly after disturbance. Ecosystem functioning (chl-a) was degraded in disturbed communities, but dispersal recovered ecosystem function to undisturbed levels. This spatial insurance for ecosystem function was mediated through changes in community composition and the relative abundance of functional groups. Results suggest that regional diversity and habitat connectivity will be important in the future to maintain ecosystem function by introducing functionally redundant species to promote compensatory dynamics. © 2012 Blackwell Publishing Ltd.
Navigation by anomalous random walks on complex networks.
Weng, Tongfeng; Zhang, Jie; Khajehnejad, Moein; Small, Michael; Zheng, Rui; Hui, Pan
2016-11-23
Anomalous random walks having long-range jumps are a critical branch of dynamical processes on networks, which can model a number of search and transport processes. However, traditional measurements based on mean first passage time are not useful as they fail to characterize the cost associated with each jump. Here we introduce a new concept of mean first traverse distance (MFTD) to characterize anomalous random walks that represents the expected traverse distance taken by walkers searching from source node to target node, and we provide a procedure for calculating the MFTD between two nodes. We use Lévy walks on networks as an example, and demonstrate that the proposed approach can unravel the interplay between diffusion dynamics of Lévy walks and the underlying network structure. Moreover, applying our framework to the famous PageRank search, we show how to inform the optimality of the PageRank search. The framework for analyzing anomalous random walks on complex networks offers a useful new paradigm to understand the dynamics of anomalous diffusion processes, and provides a unified scheme to characterize search and transport processes on networks.
Navigation by anomalous random walks on complex networks
Weng, Tongfeng; Zhang, Jie; Khajehnejad, Moein; Small, Michael; Zheng, Rui; Hui, Pan
2016-11-01
Anomalous random walks having long-range jumps are a critical branch of dynamical processes on networks, which can model a number of search and transport processes. However, traditional measurements based on mean first passage time are not useful as they fail to characterize the cost associated with each jump. Here we introduce a new concept of mean first traverse distance (MFTD) to characterize anomalous random walks that represents the expected traverse distance taken by walkers searching from source node to target node, and we provide a procedure for calculating the MFTD between two nodes. We use Lévy walks on networks as an example, and demonstrate that the proposed approach can unravel the interplay between diffusion dynamics of Lévy walks and the underlying network structure. Moreover, applying our framework to the famous PageRank search, we show how to inform the optimality of the PageRank search. The framework for analyzing anomalous random walks on complex networks offers a useful new paradigm to understand the dynamics of anomalous diffusion processes, and provides a unified scheme to characterize search and transport processes on networks.
Gluonic Regge singularities and anomalous dimensions in QCD
International Nuclear Information System (INIS)
Jaroszewicz, T.
1982-01-01
The Regge calculus results on the perturbative Pomeron are applied to deep inelastic scattering. Explicit expressions are given for the anomalous dimensions γsub(GGG)sup(n) and γsub(GF)sup(n) at n approx.= 1 to the lowest order in α and all orders in α/(n-1). (author)
anomalous left anterior cerebral artery with hypoplastic right anterior ...
African Journals Online (AJOL)
2018-02-28
Feb 28, 2018 ... We report an extremely rare anomalous variation of left anterior cerebral artery arising from the ... paraclinoid internal carotid artery and right ... Studies on the arteries of the brain: II-The anterior cerebral artery: Some anatomic ...
Theory of anomalous transport in toroidal helical plasmas
International Nuclear Information System (INIS)
Itoh, K.; Itoh, S.; Fukuyama, A.
1992-03-01
Theoretical model of the anomalous transport in Torsatron/Heliotron plasmas is developed, based on the current-diffusive interchange instability which is destabilized due to the averaged magnetic hill near edge. Analytic formula of transport coefficient is derived. This model explains the high edge transport, the power degradation and energy confinement scaling law and the enhanced heat-pulse thermal conduction. (author)
Exotic aspects of hadronic atoms-anomalous quasi-stabilities
International Nuclear Information System (INIS)
Yamazaki, Toshimitsu.
1993-07-01
Recently revealed, but hitherto unknown, new aspects of hadronic atoms, namely, anomalous quasi-stabilities of negative hadrons, are discussed. One is on long-lived antiprotonic helium atoms, characterized as 'atomic exotic halo' and the other is on deeply bound pionic atoms, characterized as 'nuclear exotic halo'. (author)
Anomalous dc resistivity and double layers in the auroral ionosphere
International Nuclear Information System (INIS)
Kindel, J.M.; Barnes, C.; Forslund, D.W.
1980-01-01
There are at least four candidate instabilities which might account for anomalous dc rereresistivity in the auroral ionosphere. These are: the ion-acoustic instability, the Buneman instability, the ion-cyclotron instability and double layers. Results are reported of computer simulations of these four instabilities which suggest that double layers are most likely to be responsible for sistivity in the auroral zone
Identification of an anomalous phase in Ni–W electrodeposits
DEFF Research Database (Denmark)
Mizushima, Io; Tang, Peter Torben; Somers, Marcel A. J.
2008-01-01
In the present work Ni–W layers electrodeposited from electrolytes based on NiSO4, Na2WO4, citrate, glycine and triethanolamine are characterized with glow discharge optical emission spectroscopy (GD-OES) and X-ray diffraction analysis (XRD). XRD showed the occurrence of an anomalous phase...
Influence of anomalous thermal losses of ignition conditions
International Nuclear Information System (INIS)
Coppi, B.; Tang, W.M.
1986-05-01
In the process of achieving ignition conditions, it is likely that microinstabilities, which lead to anomalous thermal transport of the fusing nuclei, will be present. When such phenomena are taken into account, an appropriate formulation of ignition criteria becomes necessary. In particular, a new type of plasma density limit is identified
PICTORIAL ESSAY Is anomalous origin of the left vertebral artery ...
African Journals Online (AJOL)
Is anomalous origin of the left vertebral artery indeed a rare finding? Braham van der Merwe, Christelle Ackermann, Shaun Scheepers, Sulaiman Moosa. Department of Diagnostic Radiology, Stellenbosch University and Tygerberg Academic Hospital, Tygerberg, Western Cape. Braham van der Merwe, MB ChB , DA (SA).
Anomalous scaling of stochastic processes and the Moses effect.
Chen, Lijian; Bassler, Kevin E; McCauley, Joseph L; Gunaratne, Gemunu H
2017-04-01
The state of a stochastic process evolving over a time t is typically assumed to lie on a normal distribution whose width scales like t^{1/2}. However, processes in which the probability distribution is not normal and the scaling exponent differs from 1/2 are known. The search for possible origins of such "anomalous" scaling and approaches to quantify them are the motivations for the work reported here. In processes with stationary increments, where the stochastic process is time-independent, autocorrelations between increments and infinite variance of increments can cause anomalous scaling. These sources have been referred to as the Joseph effect and the Noah effect, respectively. If the increments are nonstationary, then scaling of increments with t can also lead to anomalous scaling, a mechanism we refer to as the Moses effect. Scaling exponents quantifying the three effects are defined and related to the Hurst exponent that characterizes the overall scaling of the stochastic process. Methods of time series analysis that enable accurate independent measurement of each exponent are presented. Simple stochastic processes are used to illustrate each effect. Intraday financial time series data are analyzed, revealing that their anomalous scaling is due only to the Moses effect. In the context of financial market data, we reiterate that the Joseph exponent, not the Hurst exponent, is the appropriate measure to test the efficient market hypothesis.
Anomalous scaling of stochastic processes and the Moses effect
Chen, Lijian; Bassler, Kevin E.; McCauley, Joseph L.; Gunaratne, Gemunu H.
2017-04-01
The state of a stochastic process evolving over a time t is typically assumed to lie on a normal distribution whose width scales like t1/2. However, processes in which the probability distribution is not normal and the scaling exponent differs from 1/2 are known. The search for possible origins of such "anomalous" scaling and approaches to quantify them are the motivations for the work reported here. In processes with stationary increments, where the stochastic process is time-independent, autocorrelations between increments and infinite variance of increments can cause anomalous scaling. These sources have been referred to as the Joseph effect and the Noah effect, respectively. If the increments are nonstationary, then scaling of increments with t can also lead to anomalous scaling, a mechanism we refer to as the Moses effect. Scaling exponents quantifying the three effects are defined and related to the Hurst exponent that characterizes the overall scaling of the stochastic process. Methods of time series analysis that enable accurate independent measurement of each exponent are presented. Simple stochastic processes are used to illustrate each effect. Intraday financial time series data are analyzed, revealing that their anomalous scaling is due only to the Moses effect. In the context of financial market data, we reiterate that the Joseph exponent, not the Hurst exponent, is the appropriate measure to test the efficient market hypothesis.
Dynamic conservation of anomalous current in gauge theories
International Nuclear Information System (INIS)
Kulikov, A.V.
1986-01-01
The symmetry of classical Lagrangian of gauge fields is shown to lead in quantum theory to certain limitations for the fields interacting with gauge ones. Due to this property, additional terms appear in the effective action in the theories with anomalous currents and its gauge invariance is ensured
Partial anomalous pulmonary venous return in Turner syndrome
Hoven, A.T. van den; Chelu, R.G.; Duijnhouwer, A.L.; Demulier, L.; Devos, D.; Nieman, K.; Witsenburg, M.; Bosch, A.E. van den; Loeys, B.L.; Hagen, I.M. van; Roos-Hesselink, J.W.
2017-01-01
PURPOSE: The aim of this study is to describe the prevalence, anatomy, associations and clinical impact of partial anomalous pulmonary venous return in patients with Turner syndrome. METHODS AND RESULTS: All Turner patients who presented at our Turner clinic, between January 2007 and October 2015
Partial anomalous pulmonary venous return in Turner syndrome.
van den Hoven, Allard T; Chelu, Raluca G; Duijnhouwer, Anthonie L; Demulier, Laurent; Devos, Daniel; Nieman, Koen; Witsenburg, Maarten; van den Bosch, Annemien E; Loeys, Bart L; van Hagen, Iris M; Roos-Hesselink, Jolien W
2017-10-01
The aim of this study is to describe the prevalence, anatomy, associations and clinical impact of partial anomalous pulmonary venous return in patients with Turner syndrome. All Turner patients who presented at our Turner clinic, between January 2007 and October 2015 were included in this study and underwent ECG, echocardiography and advanced imaging such as cardiac magnetic resonance or computed tomography as part of their regular clinical workup. All imaging was re-evaluated and detailed anatomy was described. Partial anomalous pulmonary venous return was diagnosed in 24 (25%) out of 96 Turner patients included and 14 (58%) of these 24 partial anomalous pulmonary venous return had not been reported previously. Right atrial or ventricular dilatation was present in 11 (46%) of 24 partial anomalous pulmonary venous return patients. When studied with advanced imaging modalities and looked for with specific attention, PAPVR is found in 1 out of 4 Turner patients. Half of these patients had right atrial and/or ventricular dilatation. Evaluation of pulmonary venous return should be included in the standard protocol in all Turner patients. Copyright © 2017. Published by Elsevier B.V.
Electric charge quantization and the muon anomalous magnetic moment
International Nuclear Information System (INIS)
Pires, C.A.S. de; Rodrigues da Silva, P.S.
2002-01-01
We investigate some proposals to solve the electric charge quantization puzzle that simultaneously explain the recent measured deviation on the muon anomalous magnetic moment. For this we assess extensions of the electro-weak standard model spanning modifications on the scalar sector only. It is interesting to verify that one can have modest extensions which easily account for the solution for both problems
Explanation of Two Anomalous Results in Statistical Mediation Analysis
Fritz, Matthew S.; Taylor, Aaron B.; MacKinnon, David P.
2012-01-01
Previous studies of different methods of testing mediation models have consistently found two anomalous results. The first result is elevated Type I error rates for the bias-corrected and accelerated bias-corrected bootstrap tests not found in nonresampling tests or in resampling tests that did not include a bias correction. This is of special…
Anomalous hydrocracking of triglycerides over CoMo-catalyst ...
Indian Academy of Sciences (India)
Vol. 126, No. 2, March 2014, pp. 473–480. c Indian Academy of Sciences. Anomalous hydrocracking of ... to minimize condensation reaction during this process. Keywords. Coupling reactions ... normal and/or iso-alkanes.5–7 The first step in plant- oil hydroprocessing for the production of hydrocarbon fuels is saturation of ...
Anomalous heat conduction in a one-dimensional ideal gas.
Casati, Giulio; Prosen, Tomaz
2003-01-01
We provide firm convincing evidence that the energy transport in a one-dimensional gas of elastically colliding free particles of unequal masses is anomalous, i.e., the Fourier law does not hold. Our conclusions are confirmed by a theoretical and numerical analysis based on a Green-Kubo-type approach specialized to momentum-conserving lattices.
Patterns of anomalous pulmonary venous connection as seen at ...
African Journals Online (AJOL)
Supra-cardiac and intra-cardiac anomalous were the commonest type of TAPVC representing 43.6% and 35.9% respectively. Among all patients with TAPVC 51.35% were associated with ostium secundum atrial septal defect, 74.4% had moderate to severe pulmonary hypertension. Overall mortality was 9.25%. Mortality ...
Robustness in cluster analysis in the presence of anomalous observations
Zhuk, EE
Cluster analysis of multivariate observations in the presence of "outliers" (anomalous observations) in a sample is studied. The expected (mean) fraction of erroneous decisions for the decision rule is computed analytically by minimizing the intraclass scatter. A robust decision rule (stable to
Anomalous left the pulmonary dilemma coronary artery artery from a ...
African Journals Online (AJOL)
Anomalous origin ofthe left coronary artery from the pulmonary artery is an unusual congenital ... led us to review our experience of this anomaly over the past 10 years. During this .... New York: McGraw-Hill, 1978: 1345. 5. Bland EF, White PO, ...
Mass anomalous dimension in SU(2) with six fundamental fermions
DEFF Research Database (Denmark)
Bursa, Francis; Del Debbio, Luigi; Keegan, Liam
2010-01-01
We simulate SU(2) gauge theory with six massless fundamental Dirac fermions. We measure the running of the coupling and the mass in the Schroedinger Functional scheme. We observe very slow running of the coupling constant. We measure the mass anomalous dimension gamma, and find it is between 0.13...
Anomalous U(1)A and electroweak symmetry breaking
International Nuclear Information System (INIS)
Gogoladze, I.; Tsulaya, M.
2000-01-01
A new mechanism for electroweak symmetry breaking in the supersymmetric Standard Model is suggested. Our suggestion is based on the presence of an anomalous U(1) A gauge symmetry, which naturally arises in the four-dimensional superstring theory, and heavily relies on the corresponding Fayet-Illiopoulos ξ-term
Anomalous U(1)A and electroweak symmetry breaking
International Nuclear Information System (INIS)
Gogoladze, Ilia
2000-10-01
We suggest a mechanism for electroweak symmetry breaking in the Supersymmetric Standard Model. Our suggestion is based on the presence of an anomalous U(1) A gauge symmetry, which naturally arises in the four dimensional superstring theory, and heavily relies on the value of the corresponding Fayet-Illiopoulos ξ-term. (author)
Functional MRI of Conventional and Anomalous Metaphors in Mandarin Chinese
Ahrens, Kathleen; Liu, Ho-Ling; Lee, Chia-Ying; Gong, Shu-Ping; Fang, Shin-Yi; Hsu, Yuan-Yu
2007-01-01
This study looks at whether conventional and anomalous metaphors are processed in different locations in the brain while being read when compared with a literal condition in Mandarin Chinese. We find that conventional metaphors differ from the literal condition with a slight amount of increased activation in the right inferior temporal gyrus. In…
Composite scalar contributions to the anomalous magnetic moments
International Nuclear Information System (INIS)
Stremnitzer, H.
1984-01-01
It is shown that the composite scalars recently introduced to explain the high Z 0 → e + e - γ rate contribute too much to the lepton anomalous magnetic moments, unless one uses very accurate chiral symmetry or composite models with two preonic scales. (Author)
Vertices for correlated electron systems with anomalous propagators
Czech Academy of Sciences Publication Activity Database
Janiš, Václav; Pokorný, Vladislav
2014-01-01
Roč. 3, č. 1 (2014), "66-1"-"66-10" ISSN 2278-3393 R&D Projects: GA ČR GCP204/11/J042 Institutional support: RVO:68378271 Keywords : interacting quantum dot * superconducting leads * diagrammatic perturbation expansion * anomalous vertex functions Subject RIV: BM - Solid Matter Physics ; Magnetism http://www.cognizure.com/sj.aspx?p=200638479
Anomalous Magnetic and Electric Dipole Moments of the $\\tau$
Taylor, L
1998-01-01
This paper reviews the theoretical predictions for and the experimental measurements of the anomalous magnetic and electric dipole moments of the tau lepton. In particular, recent analyses of the e/sup +/e/sup -/ to tau /sup +/ tau /sup -/ gamma process from the L3 and OPAL collaborations are described. The most precise results, from L3, for the anomalous magnetic and electric dipole moments respectively are: a/sub tau /=0.004+or-0.027+or-0.023 and d /sub tau /=(0.0+or-1.5+or-1.3)*10/sup -16/ e.cm. (22 refs). This paper reviews the theoretical predictions for and the experimental measurements of the anomalous magnetic and electric dipole moments of the tau lepton. In particular, recent analyses of the $\\eettg$ process from the L3 and OPAL collaborations are described. The most precise results, from L3, for the anomalous magnetic and electric dipole moments respectively are: $\\atau = 0.004 10^{-16}{e{\\cdot}\\mathrm{cm}}$.