Lee, Hyun-Jung; Kim, Jeong-A; Lee, Mi-Ae; Park, Soon-Jung; Lee, Kyu-Ho
2013-05-01
VvhA produced by Vibrio vulnificus exhibits cytolytic activity to human cells including erythrocytes. Since haemolysis by VvhA may provide iron for bacterial growth and pathogenicity, we investigated the expression of VvhA to elucidate the regulatory roles of Fur, a major transcription factor controlling iron-homeostasis. Fur repressed the transcription of vvhBA operon via binding to the promoter region. However, haemolysin content and haemolytic activity were lowered in cell-free supernatant of fur mutant. This discrepancy between the levels of vvhA transcript and VvhA protein in fur mutant was caused by exoproteolytic activities of the elastase VvpE and another metalloprotease VvpM, which were also regulated by Fur. vvpE gene expression was repressed by Fur via binding to the Fur-box homologous region. Regulation of VvpM expression by Fur did not occur at the level of vvpM transcription. In vitro proteolysis assays showed that both proteases efficiently degraded VvhA. In addition, the extracellular levels of VvhA were higher in culture supernatants of vvpE or vvpM mutants than in the wild type. Thus this study demonstrates that Fur regulates haemolysin production at the transcription level of the vvhBA operon and at the post-translation level by regulating the expressions of two VvhA-degrading exoproteases, VvpE and VvpM.
Improving Limits on Anomalous Pseudoscalar Interactions using Few Body Calculations
NASA Astrophysics Data System (ADS)
Aldaihan, Sheakha; Snow, William Michael; Krause, Dennis
2016-09-01
Exotic long-range spin-dependent interactions between nucleons can be generated by many possible sources beyond the Standard Model. Anomalous interactions arising from exchange of ultralight bosons with pseudoscalar couplings gP between free fermions are highly suppressed in the nonrelativistic limit due to their spin dependence and suppression factors associated with the parity change at the vertex. As a consequence the experimental limits on such interactions are several orders of magnitude weaker than limits on spin-independent Yukawa interactions. We call attention to a physical process in the interaction between nucleons in separate nuclei exchanging a light pseudoscalar first identified by Krause and Fischbach which can lead to a spin independent effect and, in combination with existing experimental constraints on exotic Yukawa interactions, can improve constraints on gP for interaction ranges of atomic and mesoscopic scales. Similar nuclei models can also be used to improve constraints on P and T odd long-range interactions between scalar and pseudoscalar vertices.The theoretical evaluations of this effect will require knowledge of parity-odd matrix elements in nuclei.
Viscoelastic hydrodynamic interactions and anomalous CM diffusion in polymer melts
NASA Astrophysics Data System (ADS)
Meyer, Hendrik
We have recently discovered that anomalous center-of-mass (CM) diffusion occurring on intermediate time scales in polymer melts can be explained by the interplay of viscoelastic and hydrodynamic interactions (VHI). The theory has been solved for unentangled melts in 3D and 2D and excellent agreement between theory and simulation is found, also for alkanes with a force field optimized from neutron scattering. The physical mechanism considers that hydrodynamic interactions are not screened: they are time dependent because of increasing viscosity before the terminal relaxation time. The VHI are generally active in melts of any topology. They are most important at early times well before the terminal relaxation time and thus affect the nanosecond time range typically observable in dynamic neutron scattering experiments. We illustrate the effects with recent molecular dynamics simulations of linear, ring and star polymers. Work performed with A.N. Semenov and J. Farago.
Viscoelastic hydrodynamic interactions and anomalous CM diffusion in polymer melts
NASA Astrophysics Data System (ADS)
Meyer, Hendrik; Farago, Jean; Semenov, A. N.
2014-03-01
We have recently discovered that anomalous center-of-mass (CM) diffusion occurring on intermediate time scales in polymer melts can be explained by the interplay of viscoelastic and hydrodynamic interactions (VHI). The theory has been solved for unentangled melts in 3D and 2D and excellent agreement between theory and simulation is found. The physical mechanism considers that hydrodynamic interactions are time dependent because of increasing viscosity before the terminal relaxation time; it is generally active in melts of any topology. Surprisingly, the effects are relevant for both, momentum-conserving and Langevin dynamics and this presentation will focus on the differences: The commonly employed Langevin thermostat significantly changes the CM motion on short and intermediate time scales, but approaching the Rouse time, the melt behavior is close to momentum-conserving simulations. On the other hand, if momentum-conserving simulations are run in too small a simulation box, the result looks as if a Langevin thermostat was used.
NASA Technical Reports Server (NTRS)
Blanford, G. E., Jr.; Friedlander, M. W.; Hoppe, M.; Klarmann, J.; Walker, R. M.; Wefel, J. P.
1972-01-01
Large areas of nuclear emulsions and plastic detectors were exposed to the primary cosmic radiation during high altitude balloon flights. From the analysis of 141 particle tracks recorded during a total exposure of 1.3 x 10 to the 7th power sq m ster.sec., a charge spectrum of the VVH particles has been derived.
Anomalous absorption in CO2-laser-target interactions
NASA Astrophysics Data System (ADS)
Offenberger, A. A.; Ng, A.
1980-10-01
Efficient absorption of long-pulse CO2-laser radiation is observed to follow a transient phase of stimulated Brillouin backscatter in critical density, laminar oxygen gas target irradiation experiments. Nearly complete energy absorption occurs for not more than 10 nsec following stimulated Brillouin backscatter after which target burnthrough and refraction dominate. Inverse bremsstrahlung and resonance absorption cannot account for the general features observed. Anomalous collisions due to strong ion turbulence produced by the incident laser radiation are postulated to account for the efficient absorption.
Modeling of anomalous Wtb interactions in single top quark events using subsidiary fields
NASA Astrophysics Data System (ADS)
Boos, E.; Bunichev, V.; Dudko, L.; Perfilov, M.
2017-01-01
A method to simulate anomalous fermion-boson interactions in Wtb vertex is presented with a minimal set of simulated samples of single top quark events at the LHC energies. In the proposed method, additional subsidiary vector fields corresponding to the Standard Model gauge fields are implemented for each type of the anomalous vertex structure. The method allows to simulate a manifestation of anomalous gauge couplings in two approaches used in experimental analyses either keeping only the linear order contributions in the anomalous couplings or keeping all contributions in numerators and denominators as appeared in matrix elements. For the processes with several anomalous couplings contributing simultaneously to the production and to the decay as well as to various interference terms the method allows to model correctly the dependence of kinematic distributions on anomalous couplings. The method shows how to generate a minimum set of event samples needed for a concrete analysis. All the single top quark production mechanisms, t-, s- and associative tW-channels, are considered. The correctness of the proposed method is demonstrated.
Interaction of runaway electrons with lower hybrid waves via anomalous Doppler broadening
NASA Astrophysics Data System (ADS)
Martín-Solís, J. R.; Sánchez, R.; Esposito, B.
2002-05-01
Due to the relativistic decrease of the electron cyclotron frequency, a cyclotron resonance may appear between runaway electrons and lower hybrid waves. A single particle description of the runaway dynamics [J. R. Martín-Solís et al., Phys. Plasmas 5, 2370 (1998)] is extended to analyze the effect of the interaction of runaway electrons with lower hybrid waves via anomalous Doppler broadening. The conditions under which the resonant interaction can play a role in limiting the runaway energy are established and it is shown that, under typical lower hybrid current drive operation parameters, an efficient wave-particle coupling may occur. Observations of a fast pitch angle scattering event during the current decay phase of Ohmic discharges in the Toroidal Experiment for Technically Oriented Research (TEXTOR) [R. J. E. Jaspers, Ph.D. thesis, Technical University Eindhoven (1995)] are interpreted in terms of such interaction.
Sydorenko, D.; Kaganovich, I. D.; Chen, L.; Ventzek, P. L. G.
2015-12-15
Generation of anomalously energetic suprathermal electrons was observed in simulation of a high-voltage dc discharge with electron emission from the cathode. An electron beam produced by the emission interacts with the nonuniform plasma in the discharge via a two-stream instability. The energy transfer from the beam to the plasma electrons is ensured by the plasma nonuniformity. The electron beam excites plasma waves whose wavelength and phase speed gradually decrease towards anode. The waves with short wavelength near the anode accelerate plasma bulk electrons to suprathermal energies. The sheath near the anode reflects some of the accelerated electrons back into the plasma. These electrons travel through the plasma, reflect near the cathode, and enter the accelerating area again but with a higher energy than before. Such particles are accelerated to energies much higher than after the first acceleration. This mechanism plays a role in explaining earlier experimental observations of energetic suprathermal electrons in similar discharges.
NASA Astrophysics Data System (ADS)
Basu, Jaydeep; Begam, Nafisa; Chandran, Sivasurender; Sprung, Michael
2015-03-01
One of the central dogma of fluid physics is the no-slip boundary condition whose validity has come under intense scrutiny, especially in the fields of micro and nanofluidics. Although various studies show the violation of the no-slip condition its effect on flow of colloidal particles in viscous media has been rarely explored. Here we report unusually large reduction of effective drag experienced by polymer grafted nanoparticles moving through a highly viscous film of polymer, well above its glass transition temperature. The extent of drag reduction increases with decreasing temperature and polymer film thickness. We also observe apparent divergence of the wave vector dependent hydrodynamic interaction function of these nanoparticles with an anomalous power law exponent of ~ 2 at the lowest temperatures and film thickness. Such strong hydrodynamic interactions are not expected in polymer melts where these interactions are known to be screened to molecular dimensions. We provide evidence for the presence of large hydrodynamic slip at the nanoparticle-polymer interface and demonstrate its tunability with temperature and confinement. Our study suggests novel physics emerging in dynamics nanoparticles due to confinement and interface wettability in thin films of polymer nanocomposites.
NASA Astrophysics Data System (ADS)
Aubeneau, A. F.; Tank, J. L.; Bolster, D.; Hanrahan, B.
2014-12-01
In fluvial systems, biofilms are the main driver of biogeochemical transformations. Biofilms grow on most surfaces in the benthic and hyporheic regions, where they process waterborne solutes. These solutes are transported in the regional flow and their fluxes near the biofilms are controlled by local physical properties, such as head gradients and hydraulic conductivity. These properties are in turn influenced by the growth of the biofilm itself, which can clog porous media and/or develop its own network of porous space. Therefore, the residence time of a solute in proximity to biofilm surfaces, where it can be processed, should be influenced by the properties not only of the physical environment, but by that of the biofilm itself. We hypothesized that the presence of biofilms would increase residence times in the benthic and shallow subsurface regions of the stream bed. We performed controlled experiments in 4 experimental streams at Notre Dame's Linked Experimental Ecosystem Facility (ND-LEEF) to quantify the interaction between substrate and biofilm in controlling anomalous solute transport. Each stream at ND-LEEF had a different substrate configuration: 2 with homogeneous substrate but with different sizes (pea gravel vs. coarse gravel) and 2 with heterogeneous substrate (alternating sections vs. well-mixed reaches). We measured the evolution of the residence time distributions in the streams by injecting rhodamine tracer (RWT) multiple times over the course of a 5 month colonization gradient. Analysis of breakthrough curves demonstrated that in addition to the influence of substrate, biofilm colonization and growth significantly influenced the residence time in the system. Specifically, as biofilms grew, the power-law exponent of the RTD decreased, i.e. the tails of the distributions became heavier, suggesting prolonged retention due to the presence of the biofilms. Although the substrate signature persisted over time, with the coarser gravel bed washing out
Anomalous properties of liquids for a family of models with short range tetrahedral interactions
NASA Astrophysics Data System (ADS)
Buldyrev, Sergey; Franzese, Giancarlo
2012-02-01
Liquids with tetrahedral symmetry of the first coordination shell often display anomalous thermodynamic and dynamic behavior. The main reason for these anomalies is that pressurizing such liquids leads to the disordering of this local symmetry by the particles migrating from the second to the first coordination shell. This in some case may lead to the increase of entropy upon pressurizing and consequently to the volume increase upon cooling. Molecular simulations of various models with tetrahedral symmetry are able to reproduce this anomalous behavior. We study a family of simple models in which we can gradually change the degree of tetrahedrality and investigate the associated changes of the phase diagram by discrete molecular dynamics. A molecule in these models consist of a hard sphere and four point particles attached to the center of the hard sphere by directional bonds arranged in tetrahedral geometry. Each of these four particles has a narrow attractive square well so that the particles belonging to different molecules can attract to each other. We also impose a condition which does not allow a point particle in one molecule to include in its attractive well more than one point particle belonging to different molecules. We investigate how the phase diagram of the system depends on the parameters of the models. None of these models has a liquid -liquid phase transition in the accessible region of the phase. However, adding weak attractive square well to the hard sphere, or wider weak attractive square wells to the point particles can create a liquid-liquid critical point. A comparison with other simple models of the anomalous liquids is made.
Anomalous self-generated electrostatic fields in nanosecond laser-plasma interaction
Lancia, L.; Antici, P.; Grech, M.; Weber, S.; Marques, J.-R.; Romagnani, L.; Bourgeois, N.; Audebert, P.; Fuchs, J.; Nakatsutsumi, M.; Bellue, A.; Feugeas, J.-L.; Nicolaie, Ph.; Tikhonchuk, V. T.; Grismayer, T.; Lin, T.; Nkonga, B.; Kodama, R.
2011-03-15
Electrostatic (E) fields associated with the interaction of a well-controlled, high-power, nanosecond laser pulse with an underdense plasma are diagnosed by proton radiography. Using a current three-dimensional wave propagation code equipped with nonlinear and nonlocal hydrodynamics, we can model the measured E-fields that are driven by the laser ponderomotive force in the region where the laser undergoes filamentation. However, strong fields of up to 110 MV/m measured in the first millimeter of propagation cannot be reproduced in the simulations. This could point to the presence of unexpected strong thermal electron pressure gradients possibly linked to ion acoustic turbulence, thus emphasizing the need for the development of full kinetic collisional simulations in order to properly model laser-plasma interaction in these strongly nonlinear conditions.
Anomalous conductance of a strongly interacting Fermi gas through a quantum point contact
NASA Astrophysics Data System (ADS)
Liu, Boyang; Zhai, Hui; Zhang, Shizhong
2017-01-01
In this work we study the particle conductance of a strongly interacting Fermi gas through a quantum point contact. With an atom-molecule two-channel model, we compute the contribution to particle conductance by both the fermionic atoms and the bosonic molecules using the Keldysh formalism. Focusing on the regime above the Fermi superfluid transition temperature, we find that the fermionic contribution to the conductance is reduced by interaction compared with the quantized value for the noninteracting case; while the bosonic contribution to the conductance exhibits a plateau with nonuniversal values that is larger than the quantized conductance. This feature is particularly profound at temperature close to the superfluid transition. We emphasize that the enhanced conductance arises because of the bosonic nature of closed channel molecules and the low dimensionality of the quantum point contact.
NASA Astrophysics Data System (ADS)
Kaganovich, Igor; Sydorenko, Dmytro; Ventzek, Peter L. G.
2016-09-01
Electrons emitted from electrodes are accelerated by the sheath electric field and become the electron beams penetrating the plasma. The electron beam can interact with the plasma in collisionless manner via two-stream instability and produce suprathermal electrons. In order to understand the mechanism of suprathermal electrons acceleration, a beam-plasma system was simulated using a 1D3V particle-in-cell code EDIPIC. These simulation results show that the acceleration may be caused by the effects related to the plasma nonuniformity. The electron beam excites plasma waves whose wavelength and phase speed gradually decrease towards anode. The short waves near the anode accelerate plasma bulk electrons to suprathermal energies. Rich complexity of beam-plasma interaction phenomena was also observed: intermittency and multiple regimes of two-stream instability in a dc discharge, band structure of the growth rate of the two-stream instability of an electron beam propagating in a bounded plasma, multi-stage acceleration of electrons in a finite system. This research was funded by US Department of Energy.
NASA Astrophysics Data System (ADS)
Sydorenko, Dmytro; Kaganovich, Igor D.; Ventzek, Peter L. G.
2016-10-01
Electrons emitted from electrodes are accelerated by the sheath electric field and become the electron beams penetrating the plasma. The electron beam can interact with the plasma in collisionless manner via two-stream instability and produce suprathermal electrons. In order to understand the mechanism of suprathermal electrons acceleration, a beam-plasma system was simulated using a 1D3V particle-in-cell code EDIPIC. These simulation results show that the acceleration may be caused by the effects related to the plasma nonuniformity. The electron beam excites plasma waves whose wavelength and phase speed gradually decrease towards anode. The short waves near the anode accelerate plasma bulk electrons to suprathermal energies. Rich complexity of beam- plasma interaction phenomena was also observed: intermittency and multiple regimes of two-stream instability in a dc discharge, band structure of the growth rate of the two-stream instability of an electron beam propagating in a bounded plasma, multi-stage acceleration of electrons in a finite system.
NASA Astrophysics Data System (ADS)
Shcherbakov, Alexandre S.; Arellanes, Adan O.
2016-09-01
Regime of effective non-collinear acousto-optical interaction with tangential phase matching had been identified and previously observed only in two limiting cases: in tellurium dioxide (TeO2) at low acoustic frequencies ( 60 MHz) and in rutile (TiO2) at ultra-high frequencies ( 5 GHz). Both these limits are motivated by optical properties of the chosen materials. Low frequencies in TeO2 admit designing a wide-aperture acousto-optical cell, but limit the frequency bandwidth. While an acousto-optical cell made of TiO2 has very small aperture and exhibits low spectral resolution due to the effect of linear acoustic attenuation. Instead of those limits, we propose an advanced regime of the anomalous acousto-optical interaction with tangential phase matching, which allows us varying the frequency range and optimizing all the performances (for instance, the spectral resolution) of a wide-aperture acousto-optical cell made of the chosen crystal, as the case requires. Recently, we had suggested and successfully tested experimentally the revealed additional degree of freedom, i.e. the action of the tilt angle within the refractive indices ellipsoids to manipulate by the performances of crystalline acousto-optical cells. Now, we consider an opportunity of refining this additional degree of freedom within those ellipsoids of crystalline acousto-optical cell through some declination of the acoustic beam. For our investigations, the lithium niobate (LiNbO3) and rutile (TiO2) crystals of about 5 cm length, operating with the slow-shear acoustic mode along the acoustic axes had been selected. The needed theoretical analysis, numerical estimations, and 3D-vector diagrams have been developed to reveal potential benefits of the proposed technique.
Lepkowski, S P; Bardyszewski, Witold
2017-03-22
We study theoretically the topological phase transition and the Rashba spin-orbit interaction in electrically biased InN/GaN quantum wells. We show that that for properly chosen widths of quantum wells and barriers, one can effectively tune the system through the topological phase transition applying an external electric field perpendicular to the QW plane. We find that in InN/GaN quantum wells with the inverted band structure, when the conduction band s-type level is below the heavy hole and light hole p-type levels, the spin splitting of the subbands decreases with increasing the amplitude of the electric field in the quantum wells, which reveals the anomalous Rashba effect. Derived effective Rashba Hamiltonians can describe the subband spin splitting only for very small wave vectors due to strong coupling between the subbands. Furthermore, we demonstrate that for InN/GaN quantum wells in a Hall bar geometry, the critical voltage for the topological phase transition depends distinctly on the width of the structure and a significant spin splitting of the edge states lying in the two-dimensional band gap can be almost switched off by increasing the electric field in quantum wells only by a few percent. We show that the dependence of the spin splitting of the upper branch of the edge state dispersion curve on the wave vector has a threshold-like behavior with the on/off spin splitting ratio reaching two orders of magnitude for narrow Hall bars. The threshold wave vector depends weakly on the Hall bar width, whereas it increases significantly with the bias voltage due to an increase of the energetic distance between the s-type and p-type quantum well energy levels and a reduction of the coupling between the subbands.
NASA Astrophysics Data System (ADS)
Akbari, H.; Semeter, J. L.
2014-12-01
We and others have previously identified anomalous Incoherent Scatter Radar (ISR) spectra confined to narrow altitude ranges near the F-region peak and correlated with dynamic auroral precipitation [Isham et al., 2012; Akbari et al., 2012, 2013]. The radar echoes are attributed to beam-generated Langmuir turbulence. In this work we used a 1-dimentional Zakharov simulation to constrain the range of physical mechanisms underlying these observational features. Our results suggest the presence of a local F-region energy source, possibly produced by non-linear wave-wave interactions. In details we have found that: 1) Simultaneous enhancements in ion-line and plasma-line channels of the PFISR can be produced by strong Langmuir turbulence and caviton collapse generated by relatively strong soft electron beams (< 1 keV) that lack the electron population directly resonant with the detectable waves. 2) Except for cases of very high electron to ion temperature ratios (Tr > 6), caviton collapse would give rise to a dominant zero-frequency peak in the ion-line channel. In these cases simulated spectral features do not match those measured by ISRs. 3) Observations of enhanced ion-acoustic shoulders and lack of observation of such high temperature ratios in ISR measurements, therefore, suggest that the Parametric Decay Instability (PDI) operates at the observations wavenumbers. This in turns requires local energization of lower energy electrons (< 20 eV) at ~250 km. 4) The existence of other modes and processes is also supported by observations of non-linear features in the plasma-line measurements.
NASA Astrophysics Data System (ADS)
Arakawa, Naoya
2016-06-01
Anomalous Hall effect (AHE) and spin Hall effect (SHE) are fundamental phenomena, and their potential for application is great. However, we understand the interaction effects unsatisfactorily, and should have clarified issues about the roles of the Fermi sea term and Fermi surface term of the conductivity of the intrinsic AHE or SHE of an interacting multiorbital metal and about the effects of spin-Coulomb drag on the intrinsic SHE. Here, we resolve the first issue and provide the first step about the second issue by developing a general formalism in the linear response theory with appropriate approximations and using analytic arguments. The most striking result is that even without impurities, the Fermi surface term, a non-Berry-curvature term, plays dominant roles at high or slightly low temperatures. In particular, this Fermi surface term causes the temperature dependence of the dc anomalous Hall or spin Hall conductivity due to the interaction-induced quasiparticle damping and the correction of the dc spin Hall conductivity due to the spin-Coulomb drag. Those results revise our understanding of the intrinsic AHE and SHE. We also find that the differences between the dc anomalous Hall and longitudinal conductivities arise from the difference in the dominant multiband excitations. This not only explains why the Fermi sea term such as the Berry-curvature term becomes important in clean and low-temperature case only for interband transports, but also provides the useful principles on treating the electron-electron interaction in an interacting multiorbital metal for general formalism of transport coefficients. Several correspondences between our results and experiments are finally discussed.
NASA Astrophysics Data System (ADS)
Malov, I. F.
Many astrophysicists believe that Anomalous X-Ray Pulsars (AXP), Soft Gamma-Ray Repeaters (SGR), Rotational Radio Transients (RRAT), Compact Central Objects (CCO) and X-Ray Dim Isolated Neutron Stars (XDINS) belong to different classes of anomalous objects with neutron stars as the central bodies inducing all their observable peculiarities. We have shown earlier [1] that AXPs and SGRs could be described by the drift model in the framework of the preposition on usual properties of the central neutron star (rotation periods P 0.01 - 1 sec and, surface magnetic fields B ~ 10^11-10^13 G). Here we shall try to show that some differences of the sources under consideration will be explained by their geometry (particularly, by the angle β between their rotation and magnetic axes). If β <~ 100 (the aligned rotator) the drift waves at the outer layers of the neutron star magnetosphere should play a key role in the observable periodicity. For large values of β (the case of the nearly orthogonal rotator) an accretion from the surrounding medium (for example, from the relic disk) can cause some modulation and transient events in received radiation. Recently Kramer et al. [2] and Camilo et al. [3] have shown that AXPs J1810-197 and 1E 1547.0 - 5408 have both small angles β, that is these sources are nearly aligned rotators, and the drift model should be used for their description. On the other hand, Wang et al. [4] detected IR radiation from the cold disk around the isolated young X-ray pulsar 4U 0142+61. This was the first evidence of the disk-like matter around the neutron star. Probably there is the bimodality of anomalous pulsars. AXPs, SGRs and some radio transients belong to the population of aligned rotators with the angle between the rotation axis and the magnetic moment β < 200. These objects are described by the drift model, and their observed periods are connected with a periodicity of drift waves. Other sources have β ~ 900, and switching on's and switching off
Bouchet, Freddy; Dauxois, Thierry
2005-10-01
We explain the ubiquity and extremely slow evolution of non-Gaussian out-of-equilibrium distributions for the Hamiltonian mean-field model, by means of traditional kinetic theory. Deriving the Fokker-Planck equation for a test particle, one also unambiguously explains and predicts striking slow algebraic relaxation of the momenta autocorrelation, previously found in numerical simulations. Finally, angular anomalous diffusion are predicted for a large class of initial distributions. Non-extensive statistical mechanics is shown to be unnecessary for the interpretation of these phenomena.
Nonlocal Anomalous Hall Effect.
Zhang, Steven S-L; Vignale, Giovanni
2016-04-01
The anomalous Hall (AH) effect is deemed to be a unique transport property of ferromagnetic metals, caused by the concerted action of spin polarization and spin-orbit coupling. Nevertheless, recent experiments have shown that the effect also occurs in a nonmagnetic metal (Pt) in contact with a magnetic insulator [yttrium iron garnet (YIG)], even when precautions are taken to ensure that there is no induced magnetization in the metal. We propose a theory of this effect based on the combined action of spin-dependent scattering from the magnetic interface and the spin-Hall effect in the bulk of the metal. At variance with previous theories, we predict the effect to be of first order in the spin-orbit coupling, just as the conventional anomalous Hall effect-the only difference being the spatial separation of the spin-orbit interaction and the magnetization. For this reason we name this effect the nonlocal anomalous Hall effect and predict that its sign will be determined by the sign of the spin-Hall angle in the metal. The AH conductivity that we calculate from our theory is in order of magnitude agreement with the measured values in Pt/YIG structures.
Nonlocal Anomalous Hall Effect
NASA Astrophysics Data System (ADS)
Zhang, Steven S.-L.; Vignale, Giovanni
2016-04-01
The anomalous Hall (AH) effect is deemed to be a unique transport property of ferromagnetic metals, caused by the concerted action of spin polarization and spin-orbit coupling. Nevertheless, recent experiments have shown that the effect also occurs in a nonmagnetic metal (Pt) in contact with a magnetic insulator [yttrium iron garnet (YIG)], even when precautions are taken to ensure that there is no induced magnetization in the metal. We propose a theory of this effect based on the combined action of spin-dependent scattering from the magnetic interface and the spin-Hall effect in the bulk of the metal. At variance with previous theories, we predict the effect to be of first order in the spin-orbit coupling, just as the conventional anomalous Hall effect—the only difference being the spatial separation of the spin-orbit interaction and the magnetization. For this reason we name this effect the nonlocal anomalous Hall effect and predict that its sign will be determined by the sign of the spin-Hall angle in the metal. The AH conductivity that we calculate from our theory is in order of magnitude agreement with the measured values in Pt /YIG structures.
NASA Astrophysics Data System (ADS)
Patra, Moumita; Maiti, Santanu K.
2016-04-01
We investigate the properties of persistent charge current driven by magnetic flux in a quasi-periodic mesoscopic Fibonacci ring with Rashba and Dresselhaus spin-orbit interactions. Within a tight-binding framework we work out individual state currents together with net current based on second-quantized approach. A significant enhancement of current is observed in presence of spin-orbit coupling and sometimes it becomes orders of magnitude higher compared to the spin-orbit interaction free Fibonacci ring. We also establish a scaling relation of persistent current with ring size, associated with the Fibonacci generation, from which one can directly estimate current for any arbitrary flux, even in presence of spin-orbit interaction, without doing numerical simulation. The present analysis indeed gives a unique opportunity of determining persistent current and has not been discussed so far.
NASA Astrophysics Data System (ADS)
Al-Shakran, Mohammad; Kibler, Ludwig A.; Jacob, Timo; Ibach, Harald; Beltramo, Guillermo L.; Giesen, Margret
2016-09-01
This is Part I of two closely related papers, where we show that the specific adsorption of anions leads to a failure of the nearest-neighbor Ising model to describe island perimeter curvatures on Au(100) electrodes in dilute KBr, HCl and H2SO4 electrolytes and the therewith derived step diffusivity vs. step orientation. This result has major consequences for theoretical studies aiming at the understanding of growth, diffusion and degradation phenomena. Part I focuses on the experimental data. As shown theoretically in detail in Part II (doi:10.1016/j.susc.2016.03.022), a set of nearest-neighbor and next-nearest-neighbor interaction energies (ɛNN, ɛNNN) can uniquely be derived from the diffusivity of steps along <100> and <110>. We find strong repulsive next-nearest neighbor (NNN) interaction in KBr and HCl, whereas NNN interaction is negligibly for H2SO4. The NNN repulsive interaction energy ɛNNN therefore correlates positively with the Gibbs adsorption energy of the anions. We find furthermore that ɛNNN increases with increasing Br- and Cl- coverage. The results for ɛNN and ɛNNN are quantitatively consistent with the coverage dependence of the step line tension. We thereby establish a sound experimental base for theoretical studies on the energetics of steps in the presence of specific adsorption.
Anomalous Earth flybys of spacecraft
NASA Astrophysics Data System (ADS)
Wilhelm, Klaus; Dwivedi, Bhola N.
2015-07-01
A small deviation from the potential is expected for the gravitational interaction of extended bodies. It is explained as a consequence of a recently proposed gravitational impact model (Wilhelm et al. in Astrophys. Space Sci. 343:135-144, 2013) and has been applied to anomalous perihelion advances by Wilhelm and Dwivedi (New Astron. 31:51-55, 2014). The effect—an offset of the effective gravitational centre from the geometric centre of a spherical symmetric body—might also be responsible for the observed anomalous orbital energy gains and speed increases during Earth flybys of several spacecraft. However, close flybys would require detailed considerations of the orbit geometry. In this study, an attempt is made to explain the anomalous Earth flybys of the Galileo, NEAR Shoemaker and Rosetta spacecraft.
NASA Astrophysics Data System (ADS)
Borman, V. D.; Tronin, V. N.
2016-09-01
It has been shown that changes in the energy of a system of nonwetting liquid clusters confined in a random nanoporous medium in the process of relaxation can be written in the quasiparticle approximation in the form of the sum of the energies of local (metastable) configurations of liquid clusters interacting with clusters in the connected nearest pores. The energy spectrum and density of states of the local configuration have been calculated. It has been shown that the relaxation of the state of the system occurs through the scenario of self-organized criticality (SOC). The process is characterized by the expectation of a fluctuation necessary for overcoming a local energy barrier of the metastable state with the subsequent rapid hydrodynamic extrusion of the liquid under the action of the surface buoyancy forces of the nonwetting framework. In this case, the dependence of the interaction between local configurations on the number of filled pores belonging to the infinite percolation cluster of filled pores serves as an internal feedback initiating the SOC process. The calculations give a power-law time dependence of the relative volume of the confined liquid θ ∼t-α(α ∼ 0.1) . The developed model of the relaxation of the porous medium with the nonwetting liquid demonstrates possible mechanisms and scenarios of SOC for disordered atomic systems.
Laine, Seppo; Krause, Marita; Tabatabaei, Fatemeh S.; Siopis, Christos E-mail: mkrause@mpifr-bonn.mpg.d E-mail: christos.siopis@ulb.ac.b
2010-10-15
We obtained Spitzer/IRAC 3.6-8 {mu}m images of the nearby spiral galaxy NGC 4258 to study possible interactions between dust and the radio jet. In our analysis, we also included high-resolution radio continuum, H{alpha}, CO, and X-ray data. Our data reveal that the 8 {mu}m emission, believed to originate largely from polycyclic aromatic hydrocarbon molecules and hot dust, is an excellent tracer of the normal spiral structure in NGC 4258, and hence it originates from the galactic plane. We investigated the possibility of dust destruction by the radio jet by calculating correlation coefficients between the 8 {mu}m and radio continuum emissions along the jet in two independent ways, namely, (1) from wavelet-transformed maps of the original images at different spatial scales and (2) from one-dimensional intensity cuts perpendicular to the projected path of the radio jet on the sky. No definitive sign of a correlation (or anticorrelation) was detected on relevant spatial scales with either approach, implying that any dust destruction must take place at spatial scales that are not resolved by our observations.
Kupfer, D.H. )
1990-09-01
Each zone contains several anomalous salt properties (anomalous features). Zones cannot be characterized by any single property Zones are highly variable, lenticular, and discontinuous in detail; however, once established, they commonly have a predictable trend. The individual anomalous features can occur alone (locally in pairs) over areas of various sizes and shapes. These alone occurrences are not anomalous zones. Anomalous zones may be of any origin, and origin is not part of the definition. Typical origins include: primary (sedimentary), external sheath zone, separating two spines of salt, or caused by toroidal flow. The major importance of an anomalous zone is that it consists of various anomalous features distributed discontinuously along the zone. Thus, if three or more anomalous properties are observed together, one should look for others. The anomalous zones observed in the Gulf Coast thus far are vertical, linear, and semicontinuous. Most are reasonably straight, but some bend sharply, end abruptly, or coalesce. Textures in salt involve grain size, color (white to dark gray), grain shape, or grain distribution of the salt. Typical anomalous textures are coarse-grain, poikiloblastic, and friability. A change in color is commonplace and seldom anomalous. Structural anomalous features, broadly defined, account for most of the rest of the anomalous features. Not uncommonly they cause mining problems. Among the structural anomalous features: INCLUSIONS: Sediments, hydrocarbons, brine, gases. Common gases are air (as N{sub 2}), CH-compounds, CO{sub 2}, and H{sub 2}S. STRUCTURES: Sheared salt, undue stabbing or jointing, voids (crystal-lined pockets), permeability, increased porosity COMPOSITION: High anhydrite content, visible anhydrite as grains or boudins, very black salt = disseminated impurities such as clay.
Detecting anomalous phase synchronization from time series
Tokuda, Isao T.; Kumar Dana, Syamal; Kurths, Juergen
2008-06-15
Modeling approaches are presented for detecting an anomalous route to phase synchronization from time series of two interacting nonlinear oscillators. The anomalous transition is characterized by an enlargement of the mean frequency difference between the oscillators with an initial increase in the coupling strength. Although such a structure is common in a large class of coupled nonisochronous oscillators, prediction of the anomalous transition is nontrivial for experimental systems, whose dynamical properties are unknown. Two approaches are examined; one is a phase equational modeling of coupled limit cycle oscillators and the other is a nonlinear predictive modeling of coupled chaotic oscillators. Application to prototypical models such as two interacting predator-prey systems in both limit cycle and chaotic regimes demonstrates the capability of detecting the anomalous structure from only a few sets of time series. Experimental data from two coupled Chua circuits shows its applicability to real experimental system.
NASA Astrophysics Data System (ADS)
Ren, Li; Mi, Yi-Ming
2010-09-01
Based on the Kubo formalism, the anomalous Hall effect in a magnetic two-dimensional hole gas with cubic-Rashba spin-orbit coupling is studied in the presence of δ-function scattering potential. When the weak, short-ranged disorder scattering is considered in the Born approximation, we find that the self-energy becomes diagonal in the helicity basis and its value is independent of the wave number, and the vertex correction to the anomalous Hall conductivity due to impurity scattering vanishes when both subbands are occupied. That is to say, the anomalous Hall effect is not vanishing or influenced by the vertex correction for two-dimensional heavy-hole system, which is in sharp contrast to the case of linear-Rashba spin-orbit coupling in the electron band when the short-range disorder scattering is considered and the extrinsic mechanism as well as the effect of external electric field on the SO interaction are ignored.
Anomalous mass dimension in multiflavor QCD
NASA Astrophysics Data System (ADS)
Doff, A.; Natale, A. A.
2016-10-01
Models of strongly interacting theories with a large mass anomalous dimension (γm) provide an interesting possibility for the dynamical origin of the electroweak symmetry breaking. A laboratory for these models is QCD with many flavors, which may present a nontrivial fixed point associated to a conformal region. Studies based on conformal field theories and on Schwinger-Dyson equations have suggested the existence of bounds on the mass anomalous dimension at the fixed points of these models. In this note we discuss γm values of multiflavor QCD exhibiting a nontrivial fixed point and affected by relevant four-fermion interactions.
Anomalous diffraction approximation limits
NASA Astrophysics Data System (ADS)
Videen, Gorden; Chýlek, Petr
It has been reported in a recent article [Liu, C., Jonas, P.R., Saunders, C.P.R., 1996. Accuracy of the anomalous diffraction approximation to light scattering by column-like ice crystals. Atmos. Res., 41, pp. 63-69] that the anomalous diffraction approximation (ADA) accuracy does not depend on particle refractive index, but instead is dependent on the particle size parameter. Since this is at odds with previous research, we thought these results warranted further discussion.
NASA Astrophysics Data System (ADS)
Lapas, Luciano C.; Ferreira, Rogelma M. S.; Rubí, J. Miguel; Oliveira, Fernando A.
2015-03-01
We analyze the temperature relaxation phenomena of systems in contact with a thermal reservoir that undergoes a non-Markovian diffusion process. From a generalized Langevin equation, we show that the temperature is governed by a law of cooling of the Newton's law type in which the relaxation time depends on the velocity autocorrelation and is then characterized by the memory function. The analysis of the temperature decay reveals the existence of an anomalous cooling in which the temperature may oscillate. Despite this anomalous behavior, we show that the variation of entropy remains always positive in accordance with the second law of thermodynamics.
Lapas, Luciano C; Ferreira, Rogelma M S; Rubí, J Miguel; Oliveira, Fernando A
2015-03-14
We analyze the temperature relaxation phenomena of systems in contact with a thermal reservoir that undergoes a non-Markovian diffusion process. From a generalized Langevin equation, we show that the temperature is governed by a law of cooling of the Newton's law type in which the relaxation time depends on the velocity autocorrelation and is then characterized by the memory function. The analysis of the temperature decay reveals the existence of an anomalous cooling in which the temperature may oscillate. Despite this anomalous behavior, we show that the variation of entropy remains always positive in accordance with the second law of thermodynamics.
Lapas, Luciano C.; Ferreira, Rogelma M. S.; Rubí, J. Miguel; Oliveira, Fernando A.
2015-03-14
We analyze the temperature relaxation phenomena of systems in contact with a thermal reservoir that undergoes a non-Markovian diffusion process. From a generalized Langevin equation, we show that the temperature is governed by a law of cooling of the Newton’s law type in which the relaxation time depends on the velocity autocorrelation and is then characterized by the memory function. The analysis of the temperature decay reveals the existence of an anomalous cooling in which the temperature may oscillate. Despite this anomalous behavior, we show that the variation of entropy remains always positive in accordance with the second law of thermodynamics.
Drag suppression in anomalous chiral media
Sadofyev, Andrey V.; Yin, Yi
2016-06-01
We study a heavy impurity moving longitudinal with the direction of an external magnetic field in an anomalous chiral medium. Such system would carry a non-dissipative current of chiral magnetic effect associated with the anomaly. We show, by generalizing Landau's criterion for super fluidity, that the "anomalous component" which gives rise to the anomalous transport will not contribute to the drag experienced by an impurity. We argue on a very general basis that those systems with a strong magnetic field would exhibit an interesting transport phenomenon$-$the motion of the heavy impurity is frictionless, in analogy to the case of amore » super fluid. Finally, we demonstrate and confirm our general results with two complementary examples: weakly coupled chiral fermion gases and strongly interacting chiral liquids.« less
Drag suppression in anomalous chiral media
Sadofyev, Andrey V.; Yin, Yi
2016-06-01
We study a heavy impurity moving longitudinal with the direction of an external magnetic field in an anomalous chiral medium. Such system would carry a non-dissipative current of chiral magnetic effect associated with the anomaly. We show, by generalizing Landau's criterion for super fluidity, that the "anomalous component" which gives rise to the anomalous transport will not contribute to the drag experienced by an impurity. We argue on a very general basis that those systems with a strong magnetic field would exhibit an interesting transport phenomenon$-$the motion of the heavy impurity is frictionless, in analogy to the case of a super fluid. Finally, we demonstrate and confirm our general results with two complementary examples: weakly coupled chiral fermion gases and strongly interacting chiral liquids.
Classical Aspect of the Anomalous Magnetic Moment of the Electron
NASA Astrophysics Data System (ADS)
Bordovitsyn, V. A.; Kulikova, A. V.; Savitskaya, Yu. N.
2017-03-01
Some integral effects of electromagnetic interactions, such as the electromagnetic mass and the anomalous magnetic moment of the electron, are discussed on the basis of covariant methods of classical electrodynamics.
Kelly, Michael Lawrence
1996-04-01
An analysis of Wγ events found in 73.0 pb^{-1} collected with the D0 detector during Tevatron Run 1b is presented. Forty-six candidate events are observed with a predicted background of 13.2 events. The total cross section for p$\\bar{p}$ → Wγ + X (for p_{T}^{γ} > 10 GeV/c and ΔR_{eγ} > 0.7) times the branching ratio of W bosons to electrons is measured to be: σ(p$\\bar{p}$ → Wγ + X) x BR(W → ev) = 11.19$+2.66\\atop{-2.32}$ ± 0.61 (syst) ± 0.56 (lum) pb. 95% confidence level limits on the CP-conserving anomalous coupling parameters are set using a fit to the photon transverse energy spectrum of the events with a three-body transverse cluster mass greater than 90 GeV/c^{2}. The results are: -1.4 < Δκ < 1.4 (λ = 0) and -0.5 < λ < 0.5 (Δκ = 0) with similar limits are set on the CP-violating coupling parameters $\\bar{κ}$ and $\\bar{λ}$. These limits were set by assuming a dipole form factor with a scale factor of {Lambda} = 1.5 TeV.
Single Anomalous Production of the Fourth SM Family Leptons at Future e+e-, ep and pp Colliders
Ciftci, A. K.; Ciftci, R.; Karadeniz, H.; Sultansoy, S.; Yildiz, H. Duran
2007-04-23
Possible single productions of fourth SM family charged and neutral leptons via anomalous interactions at the future e+e-, ep, and pp colliders are studied. Signatures of such anomalous processes are argued at above colliders comparatively.
Single Anomalous Production of the Fourth SM Family Quarks at Future e+e-, ep, and pp Colliders
Ciftci, A. K.; Ciftci, R.; Sultansoy, S.; Yildiz, H. Duran
2007-04-23
Possible single productions of fourth SM family u4 and d4 quarks via anomalous interactions at the e+e-, ep, and pp colliders are investigated. Signatures of such anomalous processes are discussed at above colliders comparatively.
Beene, Darren L; Brandt, Gabriel S; Zhong, Wenge; Zacharias, Niki M; Lester, Henry A; Dougherty, Dennis A
2002-08-13
A series of tryptophan analogues has been introduced into the binding site regions of two ion channels, the ligand-gated nicotinic acetylcholine and serotonin 5-HT(3A) receptors, using unnatural amino acid mutagenesis and heterologous expression in Xenopus oocytes. A cation-pi interaction between serotonin and Trp183 of the serotonin channel 5-HT(3A)R is identified for the first time, precisely locating the ligand-binding site of this receptor. The energetic contribution of the observed cation-pi interaction between a tryptophan and the primary ammonium ion of serotonin is estimated to be approximately 4 kcal/mol, while the comparable interaction with the quaternary ammonium of acetylcholine is approximately 2 kcal/mol. The binding mode of nicotine to the nicotinic receptor of mouse muscle is examined by the same technique and found to differ significantly from that of the natural agonist, acetylcholine.
Fickian dispersion is anomalous
Cushman, John H.; O’Malley, Dan
2015-06-22
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 wemore » 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. Finally, power-law clocks are introduced to examine multi-scaling behavior. Several examples of these ideas are presented and discussed.« less
Fickian dispersion is anomalous
Cushman, John H.; O’Malley, Dan
2015-06-22
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. Finally, power-law clocks are introduced to examine multi-scaling behavior. Several examples of these ideas are presented and discussed.
Fickian dispersion is anomalous
NASA Astrophysics Data System (ADS)
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.
Anomalous spin Josephson effect
NASA Astrophysics Data System (ADS)
Wang, Mei-Juan; Wang, Jun; Hao, Lei; Liu, Jun-Feng
2016-10-01
We report a theoretical study on the spin Josephson effect arising from the exchange coupling of the two ferromagnets (Fs), which are deposited on a two-dimensional (2D) time-reversal-invariant topological insulator. An anomalous spin supercurrent Js z˜sin(α +α0) is found to flow in between the two Fs and the ground state of the system is not limited to the magnetically collinear configuration (α =n π ,n is an integer) but determined by a controllable angle α0, where α is the crossed angle between the two F magnetizations. The angle α0 is the dynamic phase of the electrons traveling in between the two Fs and can be controlled electrically by a gate voltage. This anomalous spin Josephson effect, similar to the conventional φ0 superconductor junction, originates from the definite electron chirality of the helical edge states in the 2D topological insulator. These results indicate that the magnetic coupling in a topological system is different from the usual one in conventional materials.
Fractal model of anomalous diffusion.
Gmachowski, Lech
2015-12-01
An equation of motion is derived from fractal analysis of the Brownian particle trajectory in which the asymptotic fractal dimension of the trajectory has a required value. The formula makes it possible to calculate the time dependence of the mean square displacement for both short and long periods when the molecule diffuses anomalously. The anomalous diffusion which occurs after long periods is characterized by two variables, the transport coefficient and the anomalous diffusion exponent. An explicit formula is derived for the transport coefficient, which is related to the diffusion constant, as dependent on the Brownian step time, and the anomalous diffusion exponent. The model makes it possible to deduce anomalous diffusion properties from experimental data obtained even for short time periods and to estimate the transport coefficient in systems for which the diffusion behavior has been investigated. The results were confirmed for both sub and super-diffusion.
Anomalous Cherenkov spin-orbit sound
Smirnov, Sergey
2011-02-15
The Cherenkov effect is a well-known phenomenon in the electrodynamics of fast charged particles passing through transparent media. If the particle is faster than the light in a given medium, the medium emits a forward light cone. This beautiful phenomenon has an acoustic counterpart where the role of photons is played by phonons and the role of the speed of light is played by the sound velocity. In this case the medium emits a forward sound cone. Here, we show that in a system with spin-orbit interactions in addition to this normal Cherenkov sound there appears an anomalous Cherenkov sound with forward and backward sound propagation. Furthermore, we demonstrate that the transition from the normal to anomalous Cherenkov sound happens in a singular way at the Cherenkov cone angle. The detection of this acoustic singularity therefore represents an alternative experimental tool for the measurement of the spin-orbit coupling strength.
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.
NASA Astrophysics Data System (ADS)
Wang, Xuping; Liu, Bing; Yang, Yuguo; Zhang, Yuanyuan; Lv, Xianshun; Hong, Guanglie; Shu, Rong; Yu, Haohai; Wang, Jiyang
2014-08-01
An abnormal laser deflection phenomenon in a copper-doped KTa1-xNbxO3 (Cu:KTN) crystal is demonstrated in this Letter. A near-50 mrad beam deflection angle was observed when a voltage of 1.2 kV was applied to a Cu:KTN block with size of 2.8 mm × 1.2 mm × 7.5 mm at room temperature. The special features of this deflection phenomenon are that the laser beam deflection direction is perpendicular to the electric field direction, and the beam deflection angle remains unchanged when the electric field direction is reversed. The operating principle of the phenomenon is investigated and the origin of the deflection phenomenon is attributed to an interaction between the graded refractivity effect and the quadratic electro-optic effect of the crystal.
Esposti; Fuganti; Kisiel; Tamassia
1998-10-01
The millimeter-wave rotational spectra of 79BrNO and 81BrNO in the v2 = 1 and v3 = 2 vibrational states have been reinvestigated. Measurements of the rotational spectrum in the region of maximum c-type Coriolis interaction between the two states allowed the previous analysis to be extended to account for some uncommon effects. For the most perturbed transitions the nuclear quadrupole hyperfine structure arises from coupling of not only the bromine nucleus, but also the nitrogen nucleus with the rotational angular momentum. These effects were satisfactorily fitted with a Hamiltonian describing Coriolis coupling in a molecule with two quadrupolar nuclei. The successful analysis of pure rotational transitions then allowed accurate prediction of rovibrational transitions, six of which were measured for 79BrNO and four for 81BrNO. Copyright 1998 Academic Press.
NASA Astrophysics Data System (ADS)
Wang, Xuping; Liu, Bing; Yang, Yuguo; Zhang, Yuanyuan; Lv, Xianshun; Hong, Guanglie; Shu, Rong; Yu, Haohai; Wang, Jiyang
2014-12-01
In this paper, we report an abnormal laser deflection phenomena based on quadratic electro-optic effect in copper doped KTN crystal. Cu:KTa0.62Nb0.38O3 block with size a×b×c = 2.8mm×2.6mm×12.5mm was used as beam deflection element. 75mrad beam deflection angle were observed under 1KV voltage when the laser beam across the c direction of the sample at room temperature. The special features of our experiment are that the direction of laser beam deflect perpendicular to the electric field direction, and the angular size and direction of the deflection beam remain unchanged when the electric field direction reverse. We believe that the interaction of graded refractivity and electro-optic effect leads to these special features. Besides of the special deflection mode, the deflection efficiency of our experiment also reached the world advanced level.
Anomalous - viscosity current drive
Stix, Thomas H.; Ono, Masayuki
1988-01-01
An apparatus and method for maintaining a steady-state current in a toroidal magnetically confined plasma. An electric current is generated in an edge region at or near the outermost good magnetic surface of the toroidal plasma. The edge current is generated in a direction parallel to the flow of current in the main plasma and such that its current density is greater than the average density of the main plasma current. The current flow in the edge region is maintained in a direction parallel to the main current for a period of one or two of its characteristic decay times. Current from the edge region will penetrate radially into the plasma and augment the main plasma current through the mechanism of anomalous viscosity. In another aspect of the invention, current flow driven between a cathode and an anode is used to establish a start-up plasma current. The plasma-current channel is magnetically detached from the electrodes, leaving a plasma magnetically insulated from contact with any material obstructions including the cathode and anode.
Anomalous excitation facilitation in inhomogeneously broadened Rydberg gases
NASA Astrophysics Data System (ADS)
Letscher, F.; Thomas, O.; Niederprüm, T.; Ott, H.; Fleischhauer, M.
2017-02-01
When atomic gases are laser driven to Rydberg states in an off-resonant way, a single Rydberg atom may enhance the excitation rate of surrounding atoms. This leads to a facilitated excitation referred to as Rydberg antiblockade. In the usual facilitation scenario, the detuning of the laser from resonance compensates the interaction shift. Here, we discuss a different excitation mechanism, which we call anomalous facilitation. This occurs on the "wrong side" of the resonance and originates from inhomogeneous broadening. The anomalous facilitation may be seen in experiments of attractively interacting atoms on the blue detuned side, where facilitation is not expected to appear.
Anomalous contours and illusion of angularity: phenomenal and theoretical comparisons.
Pinna, B
1991-01-01
Many experimental comparisons between real and anomalous contours have proven the functional equivalence of the two conditions; however, there are some contradictory findings. One of these is obtained by analyzing the anomalous contours in the light of a new illusion, called the 'illusion of angularity'. A circle becomes a polygon when it covers the centre of a radial arrangement of black stripes, and a polygon changes its perceptual shape depending on its orientation with respect to the same radial arrangement. Phenomenally, it appears like a very pointed polygon, in which every side is concave or, alternatively, a shape that looks like a circle with angles added in the spaces between the radial stripes, or a polygonal shape in which every side is convex. The reciprocal anomalous counterparts of these conditions, obtained by removing the geometrical/polygonal contours, reveal different results. In the first case, one sees a perfect circle; in the second case, a polygon with blunted vertices, or a circular shape with angular protrusions; in the third case, a deformed circle. These results are inconsistent with some theoretical models proposed to explain the emergence of anomalous contours, namely, all the top-down models expressed in terms of cognitive constructions and perceptual hypotheses, or in terms of global figural organizations. Rather, these comparisons suggest a different interpretation for the two phenomena (the illusion of angularity and anomalous contours). This interpretation is based on dynamic interactions or on network computations that synthesize both real and anomalous contours.
Petrology of Anomalous Eucrites
NASA Technical Reports Server (NTRS)
Mittlefehldt, D. W.; Peng, Z. X.; Ross, D. K.
2015-01-01
Most mafic achondrites can be broadly categorized as being "eucritic", that is, they are composed of a ferroan low-Ca clinopyroxene, high-Ca plagioclase and a silica phase. They are petrologically distinct from angritic basalts, which are composed of high-Ca, Al-Ti-rich clinopyroxene, Carich olivine, nearly pure anorthite and kirschsteinite, or from what might be called brachinitic basalts, which are composed of ferroan orthopyroxene and high-Ca clinopyroxene, intermediate-Ca plagioclase and ferroan olivine. Because of their similar mineralogy and composition, eucrite-like mafic achondrites formed on compositionally similar asteroids under similar conditions of temperature, pressure and oxygen fugacity. Some of them have distinctive isotopic compositions and petrologic characteristics that demonstrate formation on asteroids different from the parent of the HED clan (e.g., Ibitira, Northwest Africa (NWA) 011). Others show smaller oxygen isotopic distinctions but are otherwise petrologically and compositionally indistinguishable from basaltic eucrites (e.g., Pasamonte, Pecora Escarpment (PCA) 91007). The degree of uniformity in delta O-17 of eucrites and diogenites is one piece of evidence considered to favor of a magma-ocean scenario for their petrogenesis. Given that the O isotopic differences separating Pasamonte and PCA 91007 from other eucrites are small, and that there is an absence of other distinguishing characteristics, a legitimate question is: Did the HED parent asteroid fail to homogenize via a magma-ocean stage, thus explaining outliers like Pasamonte? We are initiating a program of study of anomalous eucrite-like achondrites as one part of our effort to seek a resolution of this issue. Here we present preliminary petrologic information on Asuka (A-) 881394, Elephant Moraine (EET) 87520 and EET 87542. We will have studied several more by conference time.
Nonlocal anomalous Hall effect
NASA Astrophysics Data System (ADS)
Zhang, Shulei; Vignale, Giovanni
Anomalous Hall effect (AHE) is a distinctive transport property of ferromagnetic metals arising from spin orbit coupling (SOC) in concert with spontaneous spin polarization. Nonetheless, recent experiments have shown that the effect also appears in a nonmagnetic metal in contact with a magnetic insulator. The main puzzle lies in the apparent absence of spin polarized electrons in the non-magnetic metal. Here, we theoretically demonstrate that the scattering of electrons from a rough metal-insulator interface is generally spin-dependent, which results in mutual conversion between spin and charge currents flowing in the plane of the layer. It is the current-carrying spin polarized electrons and the spin Hall effect in the bulk of the metal layer that conspire to generate the AH current. This novel AHE differs from the conventional one only in the spatial separation of the SOC and the magnetization, so we name it as nonlocal AHE. In contrast to other previously proposed mechanisms (e.g., spin Hall AHE and magnetic proximity effect (MPE)), the nonlocal AHE appears on the first order of spin Hall angle and does not rely on the induced moments in the metal layer, which make it experimentally detectable by contrasting the AH current directions of two layered structures such as Pt/Cu/YIG and β -Ta/Cu/YIG (with a thin inserted Cu layer to eliminate the MPE). We predict that the directions of the AH currents in these two trilayers would be opposite since the spin Hall angles of Pt and β -Ta are of opposite signs. Work supported by NSF Grants DMR-1406568.
Anomalous Conductances in an Ultracold Quantum Wire
NASA Astrophysics Data System (ADS)
Kanász-Nagy, M.; Glazman, L.; Esslinger, T.; Demler, E. A.
2016-12-01
We analyze the recently measured anomalous transport properties of an ultracold gas through a ballistic constriction [S. Krinner et al., Proc. Natl. Acad. Sci. U.S.A. 113, 8144 (2016)]. The quantized conductance observed at weak interactions increases severalfold as the gas is made strongly interacting, which cannot be explained by the Landauer theory of single-channel transport. We show that this phenomenon is due to the multichannel Andreev reflections at the edges of the constriction, where the interaction and confinement result in a superconducting state. Andreev processes convert atoms of otherwise reflecting channels into the condensate propagating through the constriction, leading to a significant excess conductance. Furthermore, we find the spin conductance being suppressed by superconductivity; the agreement with experiment provides an additional support for our model.
Macromolecular structure phasing by neutron anomalous diffraction
Cuypers, Maxime G.; Mason, Sax A.; Mossou, Estelle; Haertlein, Michael; Forsyth, V. Trevor; Mitchell, Edward P.
2016-01-01
In this report we show for the first time that neutron anomalous dispersion can be used in a practical manner to determine experimental phases of a protein crystal structure, providing a new tool for structural biologists. The approach is demonstrated through the use of a state-of-the-art monochromatic neutron diffractometer at the Institut Laue-Langevin (ILL) in combination with crystals of perdeuterated protein that minimise the level of hydrogen incoherent scattering and enhance the visibility of the anomalous signal. The protein used was rubredoxin in which cadmium replaced the iron at the iron-sulphur site. While this study was carried out using a steady-state neutron beam source, the results will be of major interest for capabilities at existing and emerging spallation neutron sources where time-of-flight instruments provide inherent energy discrimination. In particular this capability may be expected to offer unique opportunities to a rapidly developing structural biology community where there is increasing interest in the identification of protonation states, protein/water interactions and protein-ligand interactions – all of which are of central importance to a wide range of fundamental and applied areas in the biosciences. PMID:27511806
Onset of anomalous diffusion in colloids confined to quasimonolayers
NASA Astrophysics Data System (ADS)
Bleibel, J.; Domínguez, Alvaro; Oettel, M.
2017-03-01
It has been recently shown that a colloidal monolayer, e.g., formed at a fluid interface or by means of a suitable confining potential, exhibits anomalous collective diffusion. This is a consequence of the hydrodynamic interactions mediated by the three-dimensional (3D) ambient fluid when the particles are confined to reside on a two-dimensional (2D) manifold. We study theoretically and with numerical simulations the crossover from normal to anomalous diffusion as the particles are, in real systems, confined by a 3D external potential and thus have the possibility to fluctuate out of the 2D manifold, thus forming a quasimonolayer.
Catastrophic extraction of anomalous events
NASA Astrophysics Data System (ADS)
Jannson, Tomasz; Forrester, Thomas; Ro, Sookwang; Kostrzewski, Andrew
2012-06-01
In this paper we discuss extraction of anomalous events based on the theory of catastrophes, a mathematical theory of continuous geometrical manifolds with discrete singularities called catastrophes. Intelligence exploitation systems and technologies include such novel data mining techniques as automatic extraction of discrete anomalous events by software algorithms based on the theory of catastrophes, that can reduce complex problems to a few essential so-called state variables. This paper discusses mostly corank-1 catastrophes with only one state variable, for simplicity. As an example we discuss mostly avionics platforms and catastrophic failures that can be recorded by flight instruments.
Anomalous-viscosity current drive
Stix, T.H.; Ono, M.
1986-04-25
The present invention relates to a method and apparatus for maintaining a steady-state current for magnetically confining the plasma in a toroidal magnetic confinement device using anomalous viscosity current drive. A second aspect of this invention relates to an apparatus and method for the start-up of a magnetically confined toroidal plasma.
44th Annual Anomalous Absorption Conference
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
Normal and anomalous Doppler effects in periodic waveguide cyclotron maser
Korol, M.; Jerby, E.
1995-12-31
A linear analysis of the periodic-waveguide cyclotron (PWC) maser shows that the PWC interaction with fast-waves possesses properties of the known anomalous Doppler resonance interaction if the wave impedance of the resonant spatial harmonic, Z{sub n}, is much smaller than the free space impedance, i.e. if Z{sub n} {much_lt} Z{sub 0}. The feasibility of a fast-wave PWC interaction in a low impedance waveguide is examined theoretically in this paper. A practical scheme of a slotted-waveguide PWC operating in the fundamental harmonic near cutoff is proposed for a future experiment. The possible advantages of the quasi-anomalous Doppler effect in the fast-wave-PWC operating regime are the alleviation of the initial electron rotation and a high-efficiency operation.
Faraday anomalous dispersion optical tuners
NASA Technical Reports Server (NTRS)
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.
Anomalous Thermalization in Ergodic Systems
NASA Astrophysics Data System (ADS)
Luitz, David J.; Bar Lev, Yevgeny
2016-10-01
It is commonly believed that quantum isolated systems satisfying the eigenstate thermalization hypothesis (ETH) are diffusive. We show that this assumption is too restrictive since there are systems that are asymptotically in a thermal state yet exhibit anomalous, subdiffusive thermalization. We show that such systems satisfy a modified version of the ETH ansatz and derive a general connection between the scaling of the variance of the off-diagonal matrix elements of local operators, written in the eigenbasis of the Hamiltonian, and the dynamical exponent. We find that for subdiffusively thermalizing systems the variance scales more slowly with system size than expected for diffusive systems. We corroborate our findings by numerically studying the distribution of the coefficients of the eigenfunctions and the off-diagonal matrix elements of local operators of the random field Heisenberg chain, which has anomalous transport in its thermal phase. Surprisingly, this system also has non-Gaussian distributions of the eigenfunctions, thus, directly violating Berry's conjecture.
Anomalous Thermalization in Ergodic Systems.
Luitz, David J; Bar Lev, Yevgeny
2016-10-21
It is commonly believed that quantum isolated systems satisfying the eigenstate thermalization hypothesis (ETH) are diffusive. We show that this assumption is too restrictive since there are systems that are asymptotically in a thermal state yet exhibit anomalous, subdiffusive thermalization. We show that such systems satisfy a modified version of the ETH ansatz and derive a general connection between the scaling of the variance of the off-diagonal matrix elements of local operators, written in the eigenbasis of the Hamiltonian, and the dynamical exponent. We find that for subdiffusively thermalizing systems the variance scales more slowly with system size than expected for diffusive systems. We corroborate our findings by numerically studying the distribution of the coefficients of the eigenfunctions and the off-diagonal matrix elements of local operators of the random field Heisenberg chain, which has anomalous transport in its thermal phase. Surprisingly, this system also has non-Gaussian distributions of the eigenfunctions, thus, directly violating Berry's conjecture.
Colligative properties of anomalous water.
Everett, D H; Haynes, J M; McElroy, P J
1970-06-13
Investigations of the phase behaviour on freezing and subsequent melting and of other properties indicate that anomalous water is a solution containing a fixed amount of relatively involatile material in normal water. There seems to be no need to postulate the existence of a new polymer of water in such solutions. If only water and silica are present, the properties are consistent with those of a silicic acid gel.
Faraday anomalous dispersion optical filters
NASA Technical Reports Server (NTRS)
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.
Photonic versus electronic quantum anomalous Hall effect
NASA Astrophysics Data System (ADS)
Bleu, O.; Solnyshkov, D. D.; Malpuech, G.
2017-03-01
We derive the diagram of the topological phases accessible within a generic Hamiltonian describing quantum anomalous Hall effect for photons and electrons in honeycomb lattices in the presence of a Zeeman field and spin-orbit coupling (SOC). The two cases differ crucially by the winding number of their SOC, which is 1 for the Rashba SOC of electrons, and 2 for the photon SOC induced by the energy splitting between the TE and TM modes. As a consequence, the two models exhibit opposite Chern numbers ±2 at low field. Moreover, the photonic system shows a topological transition absent in the electronic case. If the photonic states are mixed with excitonic resonances to form interacting exciton-polaritons, the effective Zeeman field can be induced and controlled by a circularly polarized pump. This new feature allows an all-optical control of the topological phase transitions.
Anomalous radiation from a nonstationary plasma
NASA Astrophysics Data System (ADS)
Gradov, O. M.; Larsson, J.; Lindgren, T.; Stenflo, L.; Tegeback, R.; Uddholm, P.
1980-01-01
This paper considers the anomalous growth of the radiation intensity, which is caused by an EM wave incident on an inhomogeneous nonstationary plasma. The amplitude of the reflected signal can thus during relatively short time intervals be larger than that of the incident wave. The reason is that the plasma parameters can pass through values, for which linear resonance of leaking surface waves exist. An analytical expression is obtained for the maximum value of the intensity of the reflected wave for two different plasma density profiles, interacting with waves of different polarization. It is shown that the effect can occur repeatedly in a nonstationary plasma with a nonmonotonous density profile, if the region, where the inhomogeneity gradient changes sign, increases.
Anomalous "mapping" between pionfull and pionless EFT's
NASA Astrophysics Data System (ADS)
Yang, Ji-Feng
2014-03-01
The pion contributions to the coupling C0 of pionless EFT are studied via both non-relativistic and relativistic forms of chiral effective field theory for nuclear forces. A definite item in the 2N-reducible component of the box diagram is shown to be dominant over the 2N-irreducible (potential) ones due to the pinching of low-lying nucleon poles, and this anomalous mapping between pionless and pionfull EFT's occurs right within the non-relativistic regime. A natural strategy for renormalization of the pionfull theory emerges as a byproduct through the interactive analysis of the box diagram. Such mapping perspective may shed some light on the efficient organization of the pionfull effective field theory for nuclear forces.
Anomalous plasma diffusion and the magnetopause boundary layer
NASA Technical Reports Server (NTRS)
Treumann, Rudolf A.; Labelle, James; Haerendel, Gerhard; Pottelette, Raymond
1992-01-01
An overview of the current state of anomalous diffusion research at the magnetopause and its role in the formation of the magnetopause boundary layer is presented. Plasma wave measurements in the boundary layer indicate that most of the relevant unstable wave modes contribute negligibly to the diffusion process at the magnetopause under magnetically undisturbed northward IMF conditions. The most promising instability is the lower hybrid drift instability, which may yield diffusion coefficients of the right order if the highest measured wave intensities are assumed. It is concluded that global stationary diffusion due to wave-particle interactions does not take place at the magnetopause. Microscopic wave-particle interaction and anomalous diffusion may contribute to locally break the MD frozen-in conditions and help in transporting large amounts of magnetosheath plasma across the magnetospheric boundary.
Investigating perturbative unitarity in the presence of anomalous couplings
NASA Astrophysics Data System (ADS)
Dahiya, Mamta; Dutta, Sukanta; Islam, Rashidul
2016-03-01
We perform a model independent analysis of the helicity amplitudes at high energy for all the 2 →2 scattering processes involving gauge and Higgs bosons in the presence of anomalous W W V , W W V V , V V H , V V H H (V ≡Z , γ and W±), H H H H and H H H interactions. We obtain the perturbative unitarity constraints on anomalous couplings by demanding the vanishing of terms proportional to s2 and s3 /2 in the helicity amplitudes. Using these constraints, we also compute the upper bound on all the anomalous couplings from terms linear in s . Further, assuming all anomalous couplings to have arisen only from dimension six operators, we show that the perturbative unitarity violation can be evaded up to ˜9 TeV corresponding to the best fit values of fW W/Λ2 and fB B/Λ2 from the combined analysis of Tevatron and LHC data.
Chiral kinetic theory and anomalous hydrodynamics in even spacetime dimensions
NASA Astrophysics Data System (ADS)
Dwivedi, Vatsal; Stone, Michael
2017-04-01
We apply chiral kinetic theory to a gas of weakly interacting Weyl fermions coupled to electromagnetism in (2N + 1) + 1 spacetime dimensions to obtain the ‘Gibbs free energy current’ from which all equilibrium finite temperature anomalous contributions, such as the chiral magnetic and vortical currents, can be derived. Our results agree with those derived previously using thermodynamic constraints.
SCALING OF THE ANOMALOUS BOOST IN RELATIVISTIC JET BOUNDARY LAYER
Zenitani, Seiji; Hesse, Michael; Klimas, Alex
2010-04-01
We investigate the one-dimensional interaction of a relativistic jet and an external medium. Relativistic magnetohydrodynamic simulations show an anomalous boost of the jet fluid in the boundary layer, as previously reported. We describe the boost mechanism using an ideal relativistic fluid and magnetohydrodynamic theory. The kinetic model is also examined for further understanding. Simple scaling laws for the maximum Lorentz factor are derived, and verified by the simulations.
Faraday anomalous dispersion optical filters
NASA Technical Reports Server (NTRS)
Shay, T. M.; Yin, B.
1992-01-01
The present calculations of the performance of Faraday anomalous dispersion optical filters (FADOF) on IR transitions indicate that such filters may furnish high transmission, narrow-pass bandwidth, and low equivalent noise bandwidth under optimum operating conditions. A FADOF consists of an atomic vapor cell between crossed polarizers that are subject to a dc magnetic field along the optical path; when linearly polarized light travels along the direction of the magnetic field through the dispersive atomic vapor, a polarization rotation occurs. If FADOF conditions are suitably adjusted, a maximum transmission with very narrow bandwidth is obtained.
Galilean satellites - Anomalous temperatures disputed
NASA Technical Reports Server (NTRS)
Morrison, D.; Lebofsky, L. A.; Veeder, G. J.; Cutts, J. A.
1977-01-01
Anomalous averaged infrared brightness temperatures of the Galilean satellites of Jupiter reported by Gross (1975) are rejected as falsely conceived and lacking physical reality. It is argued that the calculations of equilibrium temperatures should be corrected, whereupon predictions would be in satisfactory agreement with observations, in conformity with the radiometric method of determining the diameters of asteroids and satellites. The IR irradiance and the related disk-averaged brightness temperature for the spectral band are recommended as more relevant. Attention is drawn to some interesting discrepancies between calculated and observed temperatures of the Jovian satellites which merit further investigation.
Minimal model for anomalous diffusion
NASA Astrophysics Data System (ADS)
Flekkøy, Eirik G.
2017-01-01
A random walk model with a local probability of removal is solved exactly and shown to exhibit subdiffusive behavior with a mean square displacement the evolves as
Geomagnetically trapped anomalous cosmic rays
Selesnick, R.S.; Cummings, A.C.; Cummings, J.R.
1995-06-01
Since its launch in July 1992, the polar-orbiting satellite SAMPEX has been collecting data on geomagnetically trapped heavy ions, predominantly O, N, and Ne, at energies {ge}15 MeV/nucleon and in a narrow L shell range L = 2. Their location, elemental composition, energy spectra, pitch angle distribution, and time variations all support the theory that these particles originated as singly ionized interplanetary anomalous cosmic rays that were stripped of electrons in the Earth`s upper atmosphere and subsequently trapped. The O are observed primarily at pitch angles outside the atmospheric loss cones, consistent with a trapped population, and their distribution there is nearly isotropic. The abundances relative to O of the N, possible Ne, and especially C are lower than the corresponding interplanetary values, which may be indicative of the trapping efficiencies. The distributions of trapped N, O, and Ne in energy and L shell suggest that most of the ions observed at the SAMPEX altitude of {approximately}600 km are not fully stripped when initially trapped. A comparison of the trapped intensity with the much lower interplanetary intensity of anomalous cosmic rays provides model-dependent estimates of the product of the trapping probability and the average trapped particle lifetime against ionization losses in the residual atmosphere for particles that mirror near the SAMPEX altitude. 36 refs., 13 figs., 1 tab.
Searching for anomalous {tau}{nu}W couplings
Rizzo, T.G.
1997-09-01
The capability of current and future measurements at low and high energy e{sup +}e{sup {minus}} colliders to probe for the existence of anomalous, CP-conserving, {tau}{nu}W dipole moment-type couplings is examined. At present, constraints on the universality of the {tau} charged and neutral current interactions as well as the shape of the {tau}{r_arrow}scr(l) energy spectrum provide the strongest bounds on such anomalous couplings. The presence of these dipole moments are shown to influence, e.g., the extraction of {alpha}{sub s}(m{sub {tau}}{sup 2}) from {tau} decays and can lead to apparent violations of CVC expectations. {copyright} {ital 1997} {ital The American Physical Society}
Anomalous extracellular diffusion in rat cerebellum.
Xiao, Fanrong; Hrabe, Jan; Hrabetova, Sabina
2015-05-05
Extracellular space (ECS) is a major channel transporting biologically active molecules and drugs in the brain. Diffusion-mediated transport of these substances is hindered by the ECS structure but the microscopic basis of this hindrance is not fully understood. One hypothesis proposes that the hindrance originates in large part from the presence of dead-space (DS) microdomains that can transiently retain diffusing molecules. Because previous theoretical and modeling work reported an initial period of anomalous diffusion in similar environments, we expected that brain regions densely populated by DS microdomains would exhibit anomalous extracellular diffusion. Specifically, we targeted granular layers (GL) of rat and turtle cerebella that are populated with large and geometrically complex glomeruli. The integrative optical imaging (IOI) method was employed to evaluate diffusion of fluorophore-labeled dextran (MW 3000) in GL, and the IOI data analysis was adapted to quantify the anomalous diffusion exponent dw from the IOI records. Diffusion was significantly anomalous in rat GL, where dw reached 4.8. In the geometrically simpler turtle GL, dw was elevated but not robustly anomalous (dw = 2.6). The experimental work was complemented by numerical Monte Carlo simulations of anomalous ECS diffusion in several three-dimensional tissue models containing glomeruli-like structures. It demonstrated that both the duration of transiently anomalous diffusion and the anomalous exponent depend on the size of model glomeruli and the degree of their wrapping. In conclusion, we have found anomalous extracellular diffusion in the GL of rat cerebellum. This finding lends support to the DS microdomain hypothesis. Transiently anomalous diffusion also has a profound effect on the spatiotemporal distribution of molecules released into the ECS, especially at diffusion distances on the order of a few cell diameters, speeding up short-range diffusion-mediated signals in less permeable
Anomalous Extracellular Diffusion in Rat Cerebellum
Xiao, Fanrong; Hrabe, Jan; Hrabetova, Sabina
2015-01-01
Extracellular space (ECS) is a major channel transporting biologically active molecules and drugs in the brain. Diffusion-mediated transport of these substances is hindered by the ECS structure but the microscopic basis of this hindrance is not fully understood. One hypothesis proposes that the hindrance originates in large part from the presence of dead-space (DS) microdomains that can transiently retain diffusing molecules. Because previous theoretical and modeling work reported an initial period of anomalous diffusion in similar environments, we expected that brain regions densely populated by DS microdomains would exhibit anomalous extracellular diffusion. Specifically, we targeted granular layers (GL) of rat and turtle cerebella that are populated with large and geometrically complex glomeruli. The integrative optical imaging (IOI) method was employed to evaluate diffusion of fluorophore-labeled dextran (MW 3000) in GL, and the IOI data analysis was adapted to quantify the anomalous diffusion exponent dw from the IOI records. Diffusion was significantly anomalous in rat GL, where dw reached 4.8. In the geometrically simpler turtle GL, dw was elevated but not robustly anomalous (dw = 2.6). The experimental work was complemented by numerical Monte Carlo simulations of anomalous ECS diffusion in several three-dimensional tissue models containing glomeruli-like structures. It demonstrated that both the duration of transiently anomalous diffusion and the anomalous exponent depend on the size of model glomeruli and the degree of their wrapping. In conclusion, we have found anomalous extracellular diffusion in the GL of rat cerebellum. This finding lends support to the DS microdomain hypothesis. Transiently anomalous diffusion also has a profound effect on the spatiotemporal distribution of molecules released into the ECS, especially at diffusion distances on the order of a few cell diameters, speeding up short-range diffusion-mediated signals in less permeable
Anomalous diffraction in hyperbolic materials
NASA Astrophysics Data System (ADS)
Alberucci, Alessandro; Jisha, Chandroth P.; Boardman, Allan D.; Assanto, Gaetano
2016-09-01
We demonstrate that light is subject to anomalous (i.e., negative) diffraction when propagating in the presence of hyperbolic dispersion. We show that light propagation in hyperbolic media resembles the dynamics of a quantum particle of negative mass moving in a two-dimensional potential. The negative effective mass implies time reversal if the medium is homogeneous. Such property paves the way to diffraction compensation, i.e., spatial analog of dispersion compensating fibers in the temporal domain. At variance with materials exhibiting standard elliptic dispersion, in inhomogeneous hyperbolic materials light waves are pulled towards regions with a lower refractive index. In the presence of a Kerr-like optical response, bright (dark) solitons are supported by a negative (positive) nonlinearity.
Persistently anomalous Pacific geomagnetic fields
NASA Astrophysics Data System (ADS)
Johnson, Catherine L.; Constable, Catherine G.
A new average geomagnetic field model for the past 3kyr (ALS3K) helps bridge a large temporal sampling gap between historical models and more traditional paleomagnetic studies spanning the last 5 Myr. A quasi-static feature seen historically in the central Pacific has the opposite sign in ALS3K; its structure is similar to, but of larger amplitude than, that in the time-averaged geomagnetic field for the last 5 Myr. Anomalous geomagnetic fields exist beneath the Pacific over timescales ranging from 10²-106 years. It is unlikely that bias over such long time scales arises from electromagnetic screening, but conceivable that the Lorentz force is influenced by long wavelength thermal variations and/or localized regions of increased electrical conductivity (associated with compositional anomalies and possibly partial melt). This is consistent with recent seismic observations of the lower mantle.
Anomalous Growth of Aging Populations
NASA Astrophysics Data System (ADS)
Grebenkov, Denis S.
2016-04-01
We consider a discrete-time population dynamics with age-dependent structure. At every time step, one of the alive individuals from the population is chosen randomly and removed with probability q_k depending on its age, whereas a new individual of age 1 is born with probability r. The model can also describe a single queue in which the service order is random while the service efficiency depends on a customer's "age" in the queue. We propose a mean field approximation to investigate the long-time asymptotic behavior of the mean population size. The age dependence is shown to lead to anomalous power-law growth of the population at the critical regime. The scaling exponent is determined by the asymptotic behavior of the probabilities q_k at large k. The mean field approximation is validated by Monte Carlo simulations.
Anomalous Sediment Mixing by Bioturbation
NASA Astrophysics Data System (ADS)
Roche, K. R.; Aubeneau, A. F.; Xie, M.; Packman, A. I.
2013-12-01
Bioturbation, the reworking of sediments by animals and plants, is the dominant mode of sediment mixing in low-energy environments, and plays an important role in sedimentary biogeochemical processes. Mixing resulting from bioturbation has historically been modeled as a diffusive process. However, diffusion models often do not provide a sufficient description of sediment mixing due to bioturbation. Stochastic models, such as the continuous time random walk (CTRW) model, provide more general descriptions of mixing behavior that are applicable even when regular diffusion assumptions are not met. Here we present results from an experimental investigation of anomalous sediment mixing by bioturbation in freshwater sediments. Clean and heavy-metal-contaminated sediments were collected from Lake DePue, a backwater lake of the Illinois River. The burrowing worm species Lumbriculus variegatus was introduced to homogenized Lake DePue sediments in aerated aquaria. We then introduced inert fine fluorescent particles to the sediment-water interface. Using time-lapse photography, we observed the mixing of the fluorescent particles into the sediment bed over a two-week period. We developed image analysis software to characterize the concentration distribution of the fluorescent particles as a function of sediment depth, and applied this to the time-series of images to evaluate sediment mixing. We fit a one-dimensional CTRW model to the depth profiles to evaluate the underlying statistical properties of the mixing behavior. This analysis suggests that the sediment mixing caused by L. variegatus burrowing is subdiffusive in time and superdiffusive in space. We also found that heavy metal contamination significantly reduces L. variegatus burrowing, causing increasingly anomalous sediment mixing. This result implies that there can be important feedbacks between sediment chemistry, organism behavior, and sediment mixing that are not considered in current environmental models.
Anomalous perturbative transport in tokamaks due to drift-wave turbulence
Thoul, A.A. ); Similon, P.L. ); Sudan, R.N. )
1994-03-01
A new method for calculating the anomalous transport in tokamak plasmas is presented. The renormalized nonlinear plasma response function is derived using the direct-interaction approximation (DIA). A complete calculation for the case of electrostatic drift-wave turbulence is presented. Explicit expressions for all coefficients of the anomalous transport matrix relating particle and heat fluxes to density and temperature gradients in the plasma are obtained. The anomalous transport matrix calculated using the DIA does not have the Onsager symmetry. As an example of application, the parameters of the Texas Experimental Tokamak (TEXT) [Nucl. Technol. Fusion [bold 1], 479 (1981)] are used to evaluate all transport coefficients numerically, as well as the spectrum modulation. The relation between the theoretical results and the experimental data is discussed. Although this paper focuses on electron transport for simplicity, the method can also be used to calculate anomalous transport due to ion instabilities, such as the ion-temperature-gradient instability.
Anomalous U(1) and low-energy physics: The power of D-flatness and holomorphy
Binetruy, P. |; Irges, N.; Ramond, P.; Lavignac, S.
1997-03-01
In models with an anomalous abelian symmetry broken at a very large scale, we study which requirements to impose on the anomalous charges in order to prevent standard model fields from acquiring large vacuum expectation values. The use of holomorphic invariants to study D-flat directions for the anomalous symmetry, proves to be a very powerful tool. We find that in order to forbid unphysical vacuum configurations at that scale, the superpotential must contain many interaction terms, including the usual Yukawa terms. Our analysis suggests that the anomalous charge of the {mu}-term is zero. It is remarkable that, together with the seesaw mechanism, and mass hierarchies, this implies a natural conservation of R-parity.
Anomalous U(1) and low-energy physics: the power of D-flatness and holomorphy
Binetruy, P.; Irges, N.; Lavignac, S.; Ramond, P.
1996-12-01
In models with an anomalous abelian symmetry broken at a very large scale, we study which requirements to impose on the anomalous charges in order to prevent standard model fields from acquiring large vacuum expectation values. The use of holomorphic invariants to study D-flat directions for the anomalous symmetry, proves to be a very powerful tool. We find that in order to forbid unphysical configurations at that scale, the superpotential must contain many interaction terms, including the usual Yukawa terms. Our analysis suggests that the anomalous charge of the {mu}-term is zero. It is remarkable that, together with the seesaw mechanism, and mass hierarchies, this implies a natural conservation of R-parity.
NASA Astrophysics Data System (ADS)
Miyake, Kazumasa
2010-02-01
Supposing the spin-triplet superconducting state of Sr2RuO4, the spin-orbit (SO) coupling associated with relative motion in Cooper pairs is calculated by extending the method for the dipole-dipole coupling given by Leggett in the superfluid 3He. It is shown that the SO coupling works only in the equal-spin pairing (ESP) state to make the pair angular momentum \\hbarL and the pair spin angular momentum id×d* parallel with each other. The SO coupling gives rise to the internal Josephson effect in a chiral ESP state as in superfluid A-phase of 3He with a help of an additional anisotropy arising from SO coupling of atomic origin which works to direct the d-vector into ab-plane. This resolves the problem of the anomalous relaxation of 17O-NQR and the structure of d-vector in Sr2RuO4.
Anomalous Light Phenomena vs. Bioelectric Brain Activity
NASA Astrophysics Data System (ADS)
Teodorani, M.; Nobili, G.
We present a research proposal concerning the instrumented investigation of anomalous light phenomena that are apparently correlated with particular mind states, such as prayer, meditation or psi. Previous research by these authors demonstrate that such light phenomena can be monitored and measured quite efficiently in areas of the world where they are reported in a recurrent way. Instruments such as optical equipment for photography and spectroscopy, VLF spectrometers, magnetometers, radar and IR viewers were deployed and used massively in several areas of the world. Results allowed us to develop physical models concerning the structural and time-variable behaviour of light phenomena, and their kinematics. Recent insights and witnesses have suggested to us that a sort of "synchronous connection" seems to exist between plasma-like phenomena and particular mind states of experiencers who seem to trigger a light manifestation which is very similar to the one previously investigated. The main goal of these authors is now aimed at the search for a concrete "entanglement-like effect" between the experiencer's mind and the light phenomena, in such a way that both aspects are intended to be monitored and measured simultaneously using appropriate instrumentation. The goal of this research project is twofold: a) to verify quantitatively the existence of one very particular kind of mind-matter interaction and to study in real time its physical and biophysical manifestations; b) to repeat the same kind of experiment using the same test-subject in different locations and under various conditions of geomagnetic activity.
Correspondence between Soft and Rapidity Anomalous Dimensions
NASA Astrophysics Data System (ADS)
Vladimirov, Alexey A.
2017-02-01
We establish a correspondence between ultraviolet singularities of soft factors for multiparticle production and rapidity singularities of soft factors for multiparton scattering. This correspondence is a consequence of the conformal mapping between scattering geometries. The correspondence is valid to all orders of perturbation theory and in this way, provides one with a proof of rapidity renormalization procedure for multiparton scattering [including the transverse momentum dependent (TMD) factorization as a special case]. As a by-product, we obtain an exact relation between the rapidity anomalous dimension and the well-known soft anomalous dimension. The three-loop expressions for TMD and a general multiparton scattering rapidity anomalous dimension are derived.
Three loop cusp anomalous dimension in QCD.
Grozin, Andrey; Henn, Johannes M; Korchemsky, Gregory P; Marquard, Peter
2015-02-13
We present the full analytic result for the three loop angle-dependent cusp anomalous dimension in QCD. With this result, infrared divergences of planar scattering processes with massive particles can be predicted to that order. Moreover, we define a closely related quantity in terms of an effective coupling defined by the lightlike cusp anomalous dimension. We find evidence that this quantity is universal for any gauge theory and use this observation to predict the nonplanar n(f)-dependent terms of the four loop cusp anomalous dimension.
Experimental phasing using zinc anomalous scattering
Cha, Sun-Shin; An, Young Jun; Jeong, Chang-Sook; Kim, Min-Kyu; Lee, Sung-Gyu; Lee, Kwang-Hoon; Oh, Byung-Ha
2012-09-01
The surface of proteins can be charged with zinc ions and the anomalous signals from these zinc ions can be used for structure determination of proteins. Zinc is a suitable metal for anomalous dispersion phasing methods in protein crystallography. Structure determination using zinc anomalous scattering has been almost exclusively limited to proteins with intrinsically bound zinc(s). Here, it is reported that multiple zinc ions can easily be charged onto the surface of proteins with no intrinsic zinc-binding site by using zinc-containing solutions. Zn derivatization of protein surfaces appears to be a largely unnoticed but promising method of protein structure determination.
Anomalous dispersion enhanced Cerenkov phase-matching
Kowalczyk, T.C.; Singer, K.D.; Cahill, P.A.
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.
Correspondence between Soft and Rapidity Anomalous Dimensions.
Vladimirov, Alexey A
2017-02-10
We establish a correspondence between ultraviolet singularities of soft factors for multiparticle production and rapidity singularities of soft factors for multiparton scattering. This correspondence is a consequence of the conformal mapping between scattering geometries. The correspondence is valid to all orders of perturbation theory and in this way, provides one with a proof of rapidity renormalization procedure for multiparton scattering [including the transverse momentum dependent (TMD) factorization as a special case]. As a by-product, we obtain an exact relation between the rapidity anomalous dimension and the well-known soft anomalous dimension. The three-loop expressions for TMD and a general multiparton scattering rapidity anomalous dimension are derived.
Anomalous Diffraction in Crystallographic Phase Evaluation
Hendrickson, Wayne A.
2014-01-01
X-ray diffraction patterns from crystals of biological macromolecules contain sufficient information to define atomic structures, but atomic positions are inextricable without having electron-density images. Diffraction measurements provide amplitudes, but the computation of electron density also requires phases for the diffracted waves. The resonance phenomenon known as anomalous scattering offers a powerful solution to this phase problem. Exploiting scattering resonances from diverse elements, the methods of multiwavelength anomalous diffraction (MAD) and single-wavelength anomalous diffraction (SAD) now predominate for de novo determinations of atomic-level biological structures. This review describes the physical underpinnings of anomalous diffraction methods, the evolution of these methods to their current maturity, the elements, procedures and instrumentation used for effective implementation, and the realm of applications. PMID:24726017
The charmonium dissociation in an ''anomalous wind''
Sadofyev, Andrey V.; Yin, Yi
2016-01-11
We study the charmonium dissociation in a strongly coupled chiral plasma in the presence of magnetic field and axial charge imbalance. This type of plasma carries "anomalous flow" induced by the chiral anomaly and exhibits novel transport phenomena such as chiral magnetic effect. We found that the "anomalous flow" would modify the charmonium color screening length by using the gauge/gravity correspondence. We derive an analytical expression quantifying the "anomalous flow" experienced by a charmonium for a large class of chiral plasma with a gravity dual. We elaborate on the similarity and it qualitative difference between anomalous effects on the charmonium color screening length which are model-dependent and those on the heavy quark drag force which are fixed by the second law of thermodynamics. As a result, we speculate on the possible charmonium dissociation induced by the chiral anomaly in heavy ion collisions.
The charmonium dissociation in an ''anomalous wind''
Sadofyev, Andrey V.; Yin, Yi
2016-01-11
We study the charmonium dissociation in a strongly coupled chiral plasma in the presence of magnetic field and axial charge imbalance. This type of plasma carries "anomalous flow" induced by the chiral anomaly and exhibits novel transport phenomena such as chiral magnetic effect. We found that the "anomalous flow" would modify the charmonium color screening length by using the gauge/gravity correspondence. We derive an analytical expression quantifying the "anomalous flow" experienced by a charmonium for a large class of chiral plasma with a gravity dual. We elaborate on the similarity and it qualitative difference between anomalous effects on the charmoniummore » color screening length which are model-dependent and those on the heavy quark drag force which are fixed by the second law of thermodynamics. As a result, we speculate on the possible charmonium dissociation induced by the chiral anomaly in heavy ion collisions.« less
Observation of anomalous Hall effect in a non-magnetic two-dimensional electron system
Maryenko, D.; Mishchenko, A. S.; Bahramy, M. S.; Ernst, A.; Falson, J.; Kozuka, Y.; Tsukazaki, A.; Nagaosa, N.; Kawasaki, M.
2017-01-01
Anomalous Hall effect, a manifestation of Hall effect occurring in systems without time-reversal symmetry, has been mostly observed in ferromagnetically ordered materials. However, its realization in high-mobility two-dimensional electron system remains elusive, as the incorporation of magnetic moments deteriorates the device performance compared to non-doped structure. Here we observe systematic emergence of anomalous Hall effect in various MgZnO/ZnO heterostructures that exhibit quantum Hall effect. At low temperatures, our nominally non-magnetic heterostructures display an anomalous Hall effect response similar to that of a clean ferromagnetic metal, while keeping a large anomalous Hall effect angle θAHE≈20°. Such a behaviour is consistent with Giovannini–Kondo model in which the anomalous Hall effect arises from the skew scattering of electrons by localized paramagnetic centres. Our study unveils a new aspect of many-body interactions in two-dimensional electron systems and shows how the anomalous Hall effect can emerge in a non-magnetic system. PMID:28300133
Observation of anomalous Hall effect in a non-magnetic two-dimensional electron system
NASA Astrophysics Data System (ADS)
Maryenko, D.; Mishchenko, A. S.; Bahramy, M. S.; Ernst, A.; Falson, J.; Kozuka, Y.; Tsukazaki, A.; Nagaosa, N.; Kawasaki, M.
2017-03-01
Anomalous Hall effect, a manifestation of Hall effect occurring in systems without time-reversal symmetry, has been mostly observed in ferromagnetically ordered materials. However, its realization in high-mobility two-dimensional electron system remains elusive, as the incorporation of magnetic moments deteriorates the device performance compared to non-doped structure. Here we observe systematic emergence of anomalous Hall effect in various MgZnO/ZnO heterostructures that exhibit quantum Hall effect. At low temperatures, our nominally non-magnetic heterostructures display an anomalous Hall effect response similar to that of a clean ferromagnetic metal, while keeping a large anomalous Hall effect angle θAHE~20°. Such a behaviour is consistent with Giovannini-Kondo model in which the anomalous Hall effect arises from the skew scattering of electrons by localized paramagnetic centres. Our study unveils a new aspect of many-body interactions in two-dimensional electron systems and shows how the anomalous Hall effect can emerge in a non-magnetic system.
Spontaneous magnetization and anomalous Hall effect in an emergent Dice lattice.
Dutta, Omjyoti; Przysiężna, Anna; Zakrzewski, Jakub
2015-06-09
Ultracold atoms in optical lattices serve as a tool to model different physical phenomena appearing originally in condensed matter. To study magnetic phenomena one needs to engineer synthetic fields as atoms are neutral. Appropriately shaped optical potentials force atoms to mimic charged particles moving in a given field. We present the realization of artificial gauge fields for the observation of anomalous Hall effect. Two species of attractively interacting ultracold fermions are considered to be trapped in a shaken two dimensional triangular lattice. A combination of interaction induced tunneling and shaking can result in an emergent Dice lattice. In such a lattice the staggered synthetic magnetic flux appears and it can be controlled with external parameters. The obtained synthetic fields are non-Abelian. Depending on the tuning of the staggered flux we can obtain either anomalous Hall effect or its quantized version. Our results are reminiscent of Anomalous Hall conductivity in spin-orbit coupled ferromagnets.
Spontaneous magnetization and anomalous Hall effect in an emergent Dice lattice
Dutta, Omjyoti; Przysiężna, Anna; Zakrzewski, Jakub
2015-01-01
Ultracold atoms in optical lattices serve as a tool to model different physical phenomena appearing originally in condensed matter. To study magnetic phenomena one needs to engineer synthetic fields as atoms are neutral. Appropriately shaped optical potentials force atoms to mimic charged particles moving in a given field. We present the realization of artificial gauge fields for the observation of anomalous Hall effect. Two species of attractively interacting ultracold fermions are considered to be trapped in a shaken two dimensional triangular lattice. A combination of interaction induced tunneling and shaking can result in an emergent Dice lattice. In such a lattice the staggered synthetic magnetic flux appears and it can be controlled with external parameters. The obtained synthetic fields are non-Abelian. Depending on the tuning of the staggered flux we can obtain either anomalous Hall effect or its quantized version. Our results are reminiscent of Anomalous Hall conductivity in spin-orbit coupled ferromagnets. PMID:26057635
Anomalous electromagnetic coupling via entanglement at the nanoscale
NASA Astrophysics Data System (ADS)
Slepyan, Gregory; Boag, Amir; Mordachev, Vladimir; Sinkevich, Eugene; Maksimenko, Sergey; Kuzhir, Polina; Miano, Giovanni; Portnoi, Mikhail E.; Maffucci, Antonio
2017-02-01
Understanding unwanted mutual interactions between devices at the nanoscale is crucial for the study of the electromagnetic compatibility in nanoelectronic and nanophotonic systems. Anomalous electromagnetic coupling (crosstalk) between nanodevices may arise from the combination of electromagnetic interaction and quantum entanglement. In this paper we study in detail the crosstalk between two identical nanodevices, each consisting of a quantum emitter (atom, quantum dot, etc), capacitively coupled to a pair of nanoelectrodes. Using the generalized susceptibility concept, the overall system is modeled as a two-port within the framework of the electrical circuit theory and it is characterized by the admittance matrix. We show that the entanglement changes dramatically the physical picture of the electromagnetic crosstalk. In particular, the excitation produced in one of the ports may be redistributed in equal parts between both the ports, in spite of the rather small electromagnetic interactions. Such an anomalous crosstalk is expected to appear at optical frequencies in lateral GaAs double quantum dots. A possible experimental set up is also discussed. The classical concepts of interference in the operation of electronic devices, which have been known since the early days of radio-communications and are associated with electromagnetic compatibility, should then be reconsidered at the nanoscale.
The Anomalous Orbital Motion Of Mab Explained
NASA Astrophysics Data System (ADS)
Kumar, Kartik; de Pater, I.; Showalter, M. R.
2012-10-01
Showalter and Lissauer (2003) reported the discovery of two previously unknown inner satellites of Uranus (Mab and Cupid), using data from the Hubble Space Telescope (HST). Subsequently, they announced the discovery of an outer ring system composed of the ν-ring and the μ-ring (Showalter and Lissauer, 2006). They showed that the orbit of Mab, embedded in the μ-ring, is not well understood, after comparing its orbital position derived from Voyager flyby data (1986) to HST data (2003-2006). The observed positions were compared with a Keplerian orbital model that included the gravitational flattening of Uranus. Although this model works well for nine other Uranian moons, for Mab the fitting errors are six times larger. Mab is relatively bright in the data and well isolated from the other moons, suggesting that the measurement errors should not be large. Hence, the magnitude of the orbit fit residual seems to indicate that we are currently overlooking an essential part of the dynamics that determines the orbit of Mab. It is clear from these discoveries that Mab and the μ-ring are intriguing, constituting "a densely packed, rapidly varying, and possibly unstable dynamical system." We investigated the nature of Mab's anomalous orbital motion, which has thus far remained unexplained. The dynamical effects we simulated result from the interaction of Mab with a hypothetical ring of undetected moonlets in its neighborhood. We explored the effects of varying the characteristics of such a ring (mass and orbital-element distribution) on Mab's orbital motion. From these results we are able to highlight a number of interesting dynamical regimes. In particular, our simulations reveal the important role that perturbers occupying horseshoe orbits might play in determining the perturbations experienced by Mab. Further studies will be conducted to investigate the long-term stability of a possible perturber ring.
Anomalous columnar order of charged colloidal platelets.
Morales-Anda, L; Wensink, H H; Galindo, A; Gil-Villegas, A
2012-01-21
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.
Anomalous baryogenesis at the weak scale
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.
ON THE SOURCE OF ASTROMETRIC ANOMALOUS REFRACTION
Taylor, M. Suzanne; McGraw, John T.; Zimmer, Peter C.; Pier, Jeffrey R.
2013-03-15
More than a century ago, astronomers using transit telescopes to determine precise stellar positions were hampered by an unexplained periodic shifting of the stars they were observing. With the advent of CCD transit telescopes in the past three decades, this unexplained motion, termed 'anomalous refraction' by these early astronomers, is again being observed. Anomalous refraction is described as a low-frequency, large angular scale ({approx}2 Degree-Sign ) motion of the entire image plane with respect to the celestial coordinate system as observed and defined by astrometric catalogs. These motions, of typically several tenths of an arcsecond amplitude with timescales on the order of 10 minutes, are ubiquitous to ground-based drift-scan astrometric measurements regardless of location or telescopes used and have been attributed to the effect of tilting of equal-density layers of the atmosphere. The cause of this tilting has often been attributed to atmospheric gravity waves, but this cause has never been confirmed. Although theoretical models of atmospheric refraction show that atmospheric gravity waves are a plausible cause of anomalous refraction, an observational campaign specifically directed at defining this relationship provides clear evidence that anomalous refraction is not consistent with the passage of atmospheric gravity waves. The source of anomalous refraction is found to be meter-scale, slowly evolving quasi-coherent dynamical structures in the boundary layer below 60 m above ground level.
Parametric probability distributions for anomalous change detection
Theiler, James P; Foy, Bernard R; Wohlberg, Brendt E; Scovel, James C
2010-01-01
The problem of anomalous change detection arises when two (or possibly more) images are taken of the same scene, but at different times. The aim is to discount the 'pervasive differences' that occur thoughout the imagery, due to the inevitably different conditions under which the images were taken (caused, for instance, by differences in illumination, atmospheric conditions, sensor calibration, or misregistration), and to focus instead on the 'anomalous changes' that actually take place in the scene. In general, anomalous change detection algorithms attempt to model these normal or pervasive differences, based on data taken directly from the imagery, and then identify as anomalous those pixels for which the model does not hold. For many algorithms, these models are expressed in terms of probability distributions, and there is a class of such algorithms that assume the distributions are Gaussian. By considering a broader class of distributions, however, a new class of anomalous change detection algorithms can be developed. We consider several parametric families of such distributions, derive the associated change detection algorithms, and compare the performance with standard algorithms that are based on Gaussian distributions. We find that it is often possible to significantly outperform these standard algorithms, even using relatively simple non-Gaussian models.
Neoclassical Viscosities and Anomalous Flows in Stellarators
NASA Astrophysics Data System (ADS)
Ware, A. S.; Spong, D. A.; Breyfogle, M.; Marine, T.
2009-05-01
We present initial work to use neoclassical viscosities calculated with the PENTA code [1] in a transport model that includes Reynolds stress generation of flows [2]. The PENTA code uses a drift kinetic equation solver to calculate neoclassical viscosities and flows in general three-dimensional geometries over a range of collisionalities. The predicted neoclassical viscosities predicted by PENTA can be flux-surfaced average and applied in a 1-D transport model that includes anomalous flow generation. This combination of codes can be used to test the impact of stellarator geometry on anomalous flow generation. As a test case, we apply the code to modeling flows in the HSX stellarator. Due to variations in the neoclassical viscosities, HSX can have strong neoclassical flows in the core region. In turn, these neoclassical flows can provide a seed for anomalous flow generation. [1] D. A. Spong, Phys. Plasmas 12, 056114 (2005). [2] D. E. Newman, et al., Phys. Plasmas 5, 938 (1998).
Models of anomalous diffusion: the subdiffusive case
NASA Astrophysics Data System (ADS)
Piryatinska, A.; Saichev, A. I.; Woyczynski, W. A.
2005-04-01
The paper discusses a model for anomalous diffusion processes. Their one-point probability density functions (p.d.f.) are exact solutions of fractional diffusion equations. The model reflects the asymptotic behavior of a jump (anomalous random walk) process with random jump sizes and random inter-jump time intervals with infinite means (and variances) which do not satisfy the Law of Large Numbers. In the case when these intervals have a fractional exponential p.d.f., the fractional Komogorov-Feller equation for the corresponding anomalous diffusion is provided and methods of finding its solutions are discussed. Finally, some statistical properties of solutions of the related Langevin equation are studied. The subdiffusive case is explored in detail. The emphasis is on a rigorous presentation which, however, would be accessible to the physical sciences audience.
A potassium Faraday anomalous dispersion optical filter
NASA Technical Reports Server (NTRS)
Yin, B.; Shay, T. M.
1992-01-01
The characteristics of a potassium Faraday anomalous dispersion optical filter operating on the blue and near infrared transitions are calculated. The results show that the filter can be designed to provide high transmission, very narrow pass bandwidth, and low equivalent noise bandwidth. The Faraday anomalous dispersion optical filter (FADOF) provides a narrow pass bandwidth (about GHz) optical filter for laser communications, remote sensing, and lidar. The general theoretical model for the FADOF has been established in our previous paper. In this paper, we have identified the optimum operational conditions for a potassium FADOF operating on the blue and infrared transitions. The signal transmission, bandwidth, and equivalent noise bandwidth (ENBW) are also calculated.
Cardiovascular magnetic resonance of anomalous coronary arteries.
Varghese, Anitha; Keegan, Jennifer; Pennell, Dudley J
2005-09-01
Cardiovascular magnetic resonance of anomalous coronary arteries is a class I indication. The term anomalous coronary artery encompasses those with an abnormal origin (from the incorrect sinus, too-high or too-low from the correct sinus, or from the pulmonary artery) and/or number of ostia. Their clinical significance results from the increased risk of myocardial infarction and sudden cardiac death associated with those traversing an interarterial course between the aorta and main pulmonary artery/right ventricular outflow tract. In this article, we review the role and practice of cardiovascular magnetic resonance in this field.
Anomalous Diffusion of a Polymer Chain in an Unentangled Melt
NASA Astrophysics Data System (ADS)
Farago, J.; Meyer, H.; Semenov, A. N.
2011-10-01
Contrary to common belief, hydrodynamic interactions in polymer melts are not screened beyond the monomer length and are important in transient regimes. We show that viscoelastic hydrodynamic interactions (VHIs) lead to anomalous dynamics of a tagged chain in an unentangled melt at t
Anomalous spin precession and spin Hall effect in semiconductor quantum wells
NASA Astrophysics Data System (ADS)
Bi, Xintao; He, Peiru; Hankiewicz, E. M.; Winkler, R.; Vignale, Giovanni; Culcer, Dimitrie
2013-07-01
Spin-orbit (SO) interactions give a spin-dependent correction r̂so to the position operator, referred to as the anomalous position operator. We study the contributions of r̂so to the spin Hall effect (SHE) in quasi-two-dimensional (2D) semiconductor quantum wells with strong band-structure SO interactions that cause spin precession. The skew scattering and side-jump scattering terms in the SHE vanish, but we identify two additional terms in the SHE, due to r̂so, which have not been considered in the literature so far. One term reflects the modification of spin precession due to the action of the external electric field (the field drives the current in the quantum well), which produces, via r̂so, an effective magnetic field perpendicular to the plane of the quantum well. The other term reflects a similar modification of spin precession due to the action of the electric field created by random impurities, and appears in a careful formulation of the Born approximation. We refer to these two effects collectively as anomalous spin precession and we note that they contribute to the SHE to the first order in the SO coupling constant even though they formally appear to be of second order. In electron systems with weak momentum scattering, the contribution of the anomalous spin precession due to the external electric field equals 1/2 the usual side-jump SHE, while the additional impurity-dependent contribution depends on the form of the band-structure SO coupling. For band-structure SO coupling linear in wave vector, the two anomalous spin precession contributions cancel. For band-structure SO coupling cubic in wave vector, however, they do not cancel, and the anomalous spin precession contribution to the SHE can be detected in a high-mobility 2D electron gas with strong SO coupling. In 2D hole systems, both anomalous spin precession contributions vanish identically.
Anomalous Cepheids in the Sculptor dwarf galaxy
Smith, H.A.; Stryker, L.L.
1986-08-01
The Sculptor dwarf galaxy contains at least three Cepheids (V25, V26, and V119), each with a period near 1 day and B magnitudes about 1.4 mag brighter than those of the Sculptor RR Lyrae stars. Low-resolution spectra of these so-called anomalous Cepheids were obtained. Metal abundances of the Cepheids have been determined by the Delta-S method and are found to be: Fe/H = -1.9 + or - 0.2, -1.8 + or - 0.2, and -2.2 + or - 0.3 for V25, V26, and V119, respectively. These values are consistent with the metal abundances of Sculptor red giants estimated from the color of the giant branch. Pulsational masses have been estimated for V25 and V26, but there is a need for improved photometry of these stars to obtain accurate results. It cannot be unambiguously established whether the Sculptor anomalous Cepheids are evolved single stars, aged about 3 Gyr, or whether they are created by mass transfer in older binary systems. The occurrence of anomalous Cepheids in other systems is discussed. There is some evidence that most anomalous Cepheids in the Small Magellanic Cloud are evolved single stars. 89 references.
RSRM Nozzle Anomalous Throat Erosion Investigation Overview
NASA Technical Reports Server (NTRS)
Clinton, R. G., Jr.; Wendel, Gary M.
1998-01-01
In September, 1996, anomalous pocketing erosion was observed in the aft end of the throat ring of the nozzle of one of the reusable solid rocket motors (RSRM 56B) used on NASA's space transportation system (STS) mission 79. The RSRM throat ring is constructed of bias tape-wrapped carbon cloth/ phenolic (CCP) ablative material. A comprehensive investigation revealed necessary and sufficient conditions for occurrence of the pocketing event and provided rationale that the solid rocket motors for the subsequent mission, STS-80, were safe to fly. The nozzles of both of these motors also exhibited anomalous erosion similar to, but less extensive than that observed on STS-79. Subsequent to this flight, the investigation to identify both the specific causes and the corrective actions for elimination of the necessary and sufficient conditions for the pocketing erosion was intensified. A detailed fault tree approach was utilized to examine potential material and process contributors to the anomalous performance. The investigation involved extensive constituent and component material property testing, pedigree assessments, supplier audits, process audits, full scale processing test article fabrication and evaluation, thermal and thermostructural analyses, nondestructive evaluation, and material performance tests conducted using hot fire simulation in laboratory test beds and subscale and full scale solid rocket motor static test firings. This presentation will provide an over-view of the observed anomalous nozzle erosion and the comprehensive, fault-tree based investigation conducted to resolve this issue.
Total least squares for anomalous change detection
Theiler, James P; Matsekh, Anna M
2010-01-01
A family of difference-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 TLSQ-based 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 furthermore it is shown to be equivalent to the optimized covariance equalization algorithm. What whitened TLSQ offers, in addition to connecting with a common language the derivations of two of the most popular anomalous change detection algorithms - chronochrome and covariance equalization - is a generalization of these algorithms with the potential for better performance.
COS NUV Detector Recovery after Anomalous Shutdown
NASA Astrophysics Data System (ADS)
Wheeler, Thomas
2013-10-01
This proposal is designed to permit a safe and orderly recovery of the NUV-MAMA detector after an anomalous shutdown. This is accomplished by using slower-than-normal MCP high-voltage ramp-ups and diagnostics. Anomalous shutdowns can occur because of bright object violations which trigger the Global Hardware Monitor or the Global Software Monitor. Anomalous shutdowns can also occur because of MAMA hardware anomalies or failures. The cause of the shutdown should be thoroughly investigated and understood prior to recovery. Twenty-four hour wait intervals are required after each test for MCP gas desorption and data analysis. Event flag 2 is used to prevent inadvertent MAMA usage.The recovery procedure consists of four separate tests {i.e. visits} to check the MAMA's health after an anomalous shutdown: 1} signal processing electronics check, 2} slow, intermediate voltage high-voltage ramp-up, 3} ramp-up to full operating voltage, and 4} fold analysis test {See COS TIR 2010-01}. Each must be successfully completed before proceeding onto the next. This proposal executes the same steps as Cycle 20 proposal 13129. Adjustments were made the the Software Global Monitor {SGM} to account for an increase in the dark counts due to window glow and to align the SGM to previously obtained Fold Analysis event data.
ACS SBC Recovery from Anomalous Shutdown
NASA Astrophysics Data System (ADS)
Wheeler, Thomas
2013-10-01
This proposal is designed to permit a safe and orderly recovery of the SBC {FUV MAMA} detector after an anomalous shutdown. This is accomplished by using slower-than-normal MCP high-voltage ramp-ups and diagnostics. Anomalous shutdowns can occur because of bright object violations, which trigger the Global Hardware Monitor or the Global Software Monitor. Anomalous shutdowns can also occur because of MAMA hardware anomalies or failures. The cause of the shutdown should be thoroughly investigated and understood prior to recovery. Twenty-four hour wait intervals are required after each test for MCP gas desorption and data analysis. Event flag 2 is used to prevent inadvertent MAMA usage. The recovery procedure consists of four separate tests {i.e. visits} to check the MAMA's health after an anomalous shutdown: 1} signal processing electronics check, 2} slow, high-voltage ramp-up to an intermediate voltage, 3} a slow high-voltage ramp-up to the nominal operating HV, and 4} fold analysis test. Each must be completed successfully before proceeding onto the next. During the two high-voltage ramp-ups, dark ACCUM exposures are taken. At high voltage, dark ACCUM exposures and diagnostics are taken. This proposal is based on Proposal 13163 from Cycle 20. For additional MAMA recovery information, see STIS ISR 98-02R.
STIS MAMA Recovery from Anomalous Shutdown
NASA Astrophysics Data System (ADS)
Wheeler, Thomas
2012-10-01
This proposal is designed to permit a safe and orderly recovery of the STIS FUV MAMA or NUV MAMA detector after an anomalous shutdown. This is accomplished by using slower-than-normal MCP high-voltage ramp-ups and diagnostics. Anomalous shutdowns can occur because of bright object violations, which trigger the Global Hardware Monitor or the Global Software Monitor. Anomalous shutdowns can also occur because of MAMA hardware anomalies or failures. The cause of the shutdown should be thoroughly investigated and understood prior to recovery. Twenty-four hour wait intervals are required after each test for MCP gas desorption and data analysis. Event flags are used to prevent inadvertent MAMA usage.The recovery procedure consists of three separate tests {i.e. visits} to check the MAMAâ_Ts health after an anomalous shutdown: 1} signal processing electronics check, 2} slow, intermediate voltage high voltage ramp-up, and 3} ramp-up to full operating voltage followed by a fold analysis test {See STIS ISR 98-02R}. Each must be successfully completed before proceeding onto the next. This proposal executes the same steps as Cycle 19 proposal 12779.
COS NUV Detector Recovery After Anomalous Shutdown
NASA Astrophysics Data System (ADS)
Wheeler, Thomas
2012-10-01
This proposal is designed to permit a safe and orderly recovery of the NUV-MAMA detector after an anomalous shutdown. This is accomplished by using slower-than-normal MCP high-voltage ramp-ups and diagnostics. Anomalous shutdowns can occur because of bright object violations, which trigger the Global Hardware Monitor or the Global Software Monitor. Anomalous shutdowns can also occur because of MAMA hardware anomalies or failures. The cause of the shutdown should be thoroughly investigated and understood prior to recovery. Twenty-four hour wait intervals are required after each test for MCP gas desorption and data analysis. Event flag 2 is used to prevent inadvertent MAMA usage.The recovery procedure consists of four separate tests {i.e. visits} to check the MAMAâ_Ts health after an anomalous shutdown: 1} signal processing electronics check, 2} slow, intermediate voltage high-voltage ramp-up, 3} ramp-up to full operating voltage, and 4} fold analysis test {See COS TIR 2010-01}. Each must be successfully completed before proceeding onto the next. This proposal executes almost the same steps as Cycle 19 proposal 12723. Adjustments were made the the Software Global Monitor {SGM} to account for an increase in the dark counts due to window glow and to align the SGM to previously obtained Fold Analysis event data.
STIS MAMA Recovery from Anomalous Shutdown
NASA Astrophysics Data System (ADS)
Wheeler, Thomas
2013-10-01
This proposal is designed to permit a safe and orderly recovery of the STIS FUV MAMA or NUV MAMA detector after an anomalous shutdown. This is accomplished by using slower-than-normal MCP high-voltage ramp-ups and diagnostics. Anomalous shutdowns can occur because of bright object violations which trigger the Global Hardware Monitor or the Global Software Monitor. Anomalous shutdowns can also occur because of MAMA hardware anomalies or failures. The cause of the shutdown should be thoroughly investigated and understood prior to recovery. Twenty-four hour wait intervals are required after each test for MCP gas desorption and data analysis. Event flags are used to prevent inadvertent MAMA usage.The recovery procedure consists of three separate tests {i.e. visits} to check the MAMA's health after an anomalous shutdown: 1} signal processing electronics check, 2} slow, intermediate voltage high voltage ramp-up, and 3} ramp-up to full operating voltage followed by a fold analysis test {See STIS ISR 98-02R}. Each must be successfully completed before proceeding onto the next. This proposal executes the same steps as Cycle 20 proposal 13150.
Anomalous transports in a time-delayed system subjected to anomalous diffusion
NASA Astrophysics Data System (ADS)
Chen, Ru-Yin; Tong, Lu-Mei; Nie, Lin-Ru; Wang, Chaojie; Pan, Wanli
2017-02-01
We investigate anomalous transports of an inertial Brownian particle in a time-delayed periodic potential subjected to an external time-periodic force, a constant bias force, and the Lévy noise. By means of numerical calculations, effect of the time delay and the Lévy noise on its mean velocity are discussed. The results indicate that: (i) The time delay can induce both multiple current reversals (CRs) and absolute negative mobility (ANM) phenomena in the system; (ii) The CRs and ANM phenomena only take place in the region of superdiffusion, while disappear in the regions of normal diffusion; (iii) The time delay can cause state transition of the system from anomalous →normal →anomalous →normal →anomalous →normal transport in the case of superdiffusion.
Towards a Better Understanding of the Anomalous Hall Effect
NASA Astrophysics Data System (ADS)
Yue, Di; Jin, Xiaofeng
2017-01-01
Recent experimental efforts to identify the intrinsic and extrinsic contributions in the anomalous Hall effect are reviewed. Benefited from the experimental control of artificial impurity density in single crystalline magnetic thin films, a comprehensive physical picture of the anomalous Hall effect involving multiple competing scattering processes has been established. Some new insights into the microscopic mechanisms of the anomalous Hall effect are discussed.
The Comprehension of Anomalous Sentences: Evidence from Structural Priming
ERIC Educational Resources Information Center
Ivanova, Iva; Pickering, Martin J.; Branigan, Holly P.; McLean, Janet F.; Costa, Albert
2012-01-01
We report three experiments investigating how people process anomalous sentences, in particular those in which the anomaly is associated with the verb. We contrast two accounts for the processing of such anomalous sentences: a syntactic account, in which the representations constructed for anomalous sentences are similar in nature to the ones…
Anomalous dispersions of `hedgehog' particles
NASA Astrophysics Data System (ADS)
Bahng, Joong Hwan; Yeom, Bongjun; Wang, Yichun; Tung, Siu On; Hoff, J. Damon; Kotov, Nicholas
2015-01-01
Hydrophobic particles in water and hydrophilic particles in oil aggregate, but can form colloidal dispersions if their surfaces are chemically camouflaged with surfactants, organic tethers, adsorbed polymers or other particles that impart affinity for the solvent and increase interparticle repulsion. A different strategy for modulating the interaction between a solid and a liquid uses surface corrugation, which gives rise to unique wetting behaviour. Here we show that this topographical effect can also be used to disperse particles in a wide range of solvents without recourse to chemicals to camouflage the particles' surfaces: we produce micrometre-sized particles that are coated with stiff, nanoscale spikes and exhibit long-term colloidal stability in both hydrophilic and hydrophobic media. We find that these `hedgehog' particles do not interpenetrate each other with their spikes, which markedly decreases the contact area between the particles and, therefore, the attractive forces between them. The trapping of air in aqueous dispersions, solvent autoionization at highly developed interfaces, and long-range electrostatic repulsion in organic media also contribute to the colloidal stability of our particles. The unusual dispersion behaviour of our hedgehog particles, overturning the notion that like dissolves like, might help to mitigate adverse environmental effects of the use of surfactants and volatile organic solvents, and deepens our understanding of interparticle interactions and nanoscale colloidal chemistry.
Anomalous surface diffusion of protons on lipid membranes.
Wolf, Maarten G; Grubmüller, Helmut; Groenhof, Gerrit
2014-07-01
The cellular energy machinery depends on the presence and properties of protons at or in the vicinity of lipid membranes. To asses the energetics and mobility of a proton near a membrane, we simulated an excess proton near a solvated DMPC bilayer at 323 K, using a recently developed method to include the Grotthuss proton shuttling mechanism in classical molecular dynamics simulations. We obtained a proton surface affinity of -13.0 ± 0.5 kJ mol(-1). The proton interacted strongly with both lipid headgroup and linker carbonyl oxygens. Furthermore, the surface diffusion of the proton was anomalous, with a subdiffusive regime over the first few nanoseconds, followed by a superdiffusive regime. The time- and distance dependence of the proton surface diffusion coefficient within these regimes may also resolve discrepancies between previously reported diffusion coefficients. Our simulations show that the proton anomalous surface diffusion originates from restricted diffusion in two different surface-bound states, interrupted by the occasional bulk-mediated long-range surface diffusion. Although only a DMPC membrane was considered in this work, we speculate that the restrictive character of the on-surface diffusion is highly sensitive to the specific membrane conditions, which can alter the relative contributions of the surface and bulk pathways to the overall diffusion process. Finally, we discuss the implications of our findings for the energy machinery.
Remote sensing and characterization of anomalous debris
NASA Technical Reports Server (NTRS)
Sridharan, R.; Beavers, W.; Lambour, R.; Gaposchkin, E. M.; Kansky, J.; Stansbery, E.
1997-01-01
The analysis of orbital debris data shows a band of anomalously high debris concentration in the altitude range between 800 and 1000 km. Analysis indicates that the origin is the leaking coolant fluid from nuclear power sources that powered a now defunct Soviet space-based series of ocean surveillance satellites. A project carried out to detect, track and characterize a sample of the anomalous debris is reported. The nature of the size and shape of the sample set, and the possibility of inferring the composition of the droplets were assessed. The technique used to detect, track and characterize the sample set is described and the results of the characterization analysis are presented. It is concluded that the nature of the debris is consistent with leaked Na-K fluid, although this cannot be proved with the remote sensing techniques used.
Anomalous feedback and negative domain wall resistance
NASA Astrophysics Data System (ADS)
Cheng, Ran; Zhu, Jian-Gang; Xiao, Di
2016-11-01
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.
The resurgence of the cusp anomalous dimension
NASA Astrophysics Data System (ADS)
Aniceto, Inês
2016-02-01
This work addresses the resurgent properties of the cusp anomalous dimension’s strong coupling expansion, obtained from the integral Beisert-Eden-Staudacher (BES) equation. This expansion is factorially divergent, and its first non-perturbative corrections are related to the mass gap of the O(6)σ -model. The factorial divergence can also be analyzed from a resurgence perspective. Building on the work of Basso and Korchemsky, a transseries ansatz for the cusp anomalous dimension is proposed and the corresponding expected large-order behaviour studied. One finds non-perturbative phenomena in both the positive and negative real coupling directions, which need to be included to address the analyticity conditions coming from the BES equation. After checking the resurgence structure of the proposed transseries, it is shown that it naturally leads to an unambiguous resummation procedure, furthermore allowing for a strong/weak coupling interpolation.
Anomalous magnetic viscosity in relativistic accretion disks
NASA Astrophysics Data System (ADS)
Lin, Fujun; Liu, Sanqiu; Li, Xiaoqing
2013-07-01
It has been proved that the self-generated magnetic fields by transverse plasmons in the relativistic regime are modulationally unstable, leading to a self-similar collapse of the magnetic flux tubes and resulting in local magnetic structures; highly spatially intermittent flux is responsible for generating the anomalous viscosity. We derive the anomalous magnetic viscosity coefficient, in accretion disks around compact objects, such as black holes, pulsars and quasars, where the plasmas are relativistic, in order to help clarify the nature of viscosity in the theory of accretion disks. The results indicate that, the magnetic viscosity is modified by the relativistic effects of plasmas, and its' strength would be 1015 stronger than the molecular viscosity, which may be helpful in explaining the observations.
Neoclassical Viscosities and Anomalous Flows in Stellarators
NASA Astrophysics Data System (ADS)
Ware, A. S.; Spong, D. A.
2008-11-01
We discuss initial work to use neoclassical viscosities calculated with the PENTA code [1,2] in a transport model that includes Reynolds stress generation of flows [3]. The PENTA code uses a drift kinetic equation solver to calculate neoclassical viscosities and flows in general three-dimensional geometries over a range of collisionalities. The predicted neoclassical viscosities predicted by PENTA can be flux-surfaced average and applied in a 1-D transport model that includes anomalous flow generation. This combination of codes can be used to test the impact of stellarator geometry on anomalous flow generation. [1] D. A. Spong, Phys. Plasmas 12, 056114 (2005). [2] D. A. Spong, Fusion Sci. Technology 50, 343 (2006). [3] D. E. Newman, et al., Phys. Plasmas 5, 938 (1998).
Anomalous superficial ulnar artery based flap
Ramani, C. V.; Kundagulwar, Girish K.; Prabha, Yadav S.; Dushyanth, Jaiswal
2014-01-01
Upper limb shows a large number of arterial variations. This case report describes the presence of additional superficial ulnar artery which was used to raise a pedicle flap to cover an arm defect thus avoided using the main vessel of the forearm - radial or ulnar artery. Vascular anomalies occurring in the arm and forearm tend to increase the likelihood of damaging the superficial anomalous arteries during surgery. Superficial ulnar or radial arteries have been described to originate from the upper third of the brachial artery; here we report the origin of the anomalous superficial ulnar artery originating from the brachial artery at the level of elbow with the concomitant presence of normal deep radial and ulnar arteries. PMID:24987217
Method for identifying anomalous terrestrial heat flows
Del Grande, Nancy Kerr
1977-01-25
A method for locating and mapping the magnitude and extent of terrestrial heat-flow anomalies from 5 to 50 times average with a tenfold improved sensitivity over orthodox applications of aerial temperature-sensing surveys as used for geothermal reconnaissance. The method remotely senses surface temperature anomalies such as occur from geothermal resources or oxidizing ore bodies by: measuring the spectral, spatial, statistical, thermal, and temporal features characterizing infrared radiation emitted by natural terrestrial surfaces; deriving from these measurements the true surface temperature with uncertainties as small as 0.05 to 0.5 K; removing effects related to natural temperature variations of topographic, hydrologic, or meteoric origin, the surface composition, detector noise, and atmospheric conditions; factoring out the ambient normal-surface temperature for non-thermally enhanced areas surveyed under otherwise identical environmental conditions; distinguishing significant residual temperature enhancements characteristic of anomalous heat flows and mapping the extent and magnitude of anomalous heat flows where they occur.
Anomalous gluon content of the proton
NASA Astrophysics Data System (ADS)
Hatsuda, T.
1990-01-01
The proton matrix element of the flavor singlet axial current is evaluated using the large Nc chiral dynamics satisfying the anomalous Ward-Takahashi identities. We relate the quark and gluon contributions ( Δq and Δg) of the matrix element to the nucleon-meson ( η, η', π0) pseudo-scalar coupling constants. It is shown that the weak η'-nucleon coupling is preferred to reproduce the recent EMC data. The origin of the anomalous value of Δg pointed out by Cheng and Li is clarified in the context of the large isospin violation due to the anomaly. A subtlety related to the matrix element of the gauge-variant topological current Kμ is also discussed.
Anomalous toroidal field penetration in Tormac V
Feinberg, B.; Vaucher, B. G.; Shaw, R. S.; Vella, M. C.
1981-07-01
We investigate magnetic field penetration into a cool, collisional, magnetized plasma in Tormac V. Magnetic probe and laser interferometer studies reveal anomalous penetration of the applied toroidal field into a plasma with an initial parallel bias toroidal field. The applied poloidal field, however, formed a well-defined magnetic front which was effective at sweeping up particles. Lastly, strong shear in the vacuum magnetic field does not inhibit the apparent decoupling of the applied toroidal field from the applied poloidal field.
Anomalous Charge Transport in Disordered Organic Semiconductors
Muniandy, S. V.; Woon, K. L.; Choo, K. Y.
2011-03-30
Anomalous charge carrier transport in disordered organic semiconductors is studied using fractional differential equations. The connection between index of fractional derivative and dispersion exponent is examined from the perspective of fractional Fokker-Planck equation and its link to the continuous time random walk formalism. The fractional model is used to describe the bi-scaling power-laws observed in the time-of flight photo-current transient data for two different types of organic semiconductors.
Anomalous Water and Other Polymeric Materials
could be called anomalous in some ways, no material that gives the exact spectrum of ’ polywater ’ could be found. An interesting and previously...unreported form of sodium carbonate is formed when this compound crystallizes from methanol. Yields of the polywater -like material seem to vary greatly from...laboratory to laboratory, even when simple procedures that are seen to work in one are tried in another. Polywater -like material can be formed from
Anomalous transport and possible phase transition in palladium nanojunctions.
Scott, Gavin D; Palacios, Juan J; Natelson, Douglas
2010-05-25
Many phenomena in condensed matter are thought to result from competition between different ordered phases. Palladium is a paramagnetic metal close to both ferromagnetism and superconductivity and is, therefore, a potentially interesting material to consider. Nanoscale structuring of matter can modify relevant physical energy scales, leading to effects such as locally modified magnetic interactions. We present transport measurements in electromigrated palladium break junction devices showing the emergence at low temperatures of anomalous sharp features in the differential conductance. These features appear symmetrically in applied bias and exhibit a temperature dependence of their characteristic voltages reminiscent of a mean-field phase transition. The systematic variation of these voltages with zero bias conductance, together with density functional theory calculations illustrating the relationship between the magnetization of Pd and atomic coordination, suggests that the features may result from the onset of spontaneous magnetization in the nanojunction electrodes. We propose that the characteristic conductance features are related to inelastic tunneling involving magnetic excitations.
Anomalous diffusion of a polymer chain in an unentangled melt
NASA Astrophysics Data System (ADS)
Farago, Jean; Meyer, Hendrik; Semenov, Alexander
2012-02-01
Contrary to common belief, the hydrodynamic interactions (HI) in polymer melts are not screened beyond the monomer length and are important in transient regimes. We show that the viscoelastic HI effects (VHI) lead to anomalous dynamics of a tagged chain in an unentangled melt at t < tN (tN, the Rouse time). The chain centre-of-mass (CM) mean-square displacement is enhanced (as compared to the Rouse diffusion) by a large factor increasing with chain length. We develop an analytical theory of VHI-controlled chain dynamics yielding negative CM velocity autocorrelation function which quantitatively agrees with our MD simulations without any fitting parameter. It is also shown that the Langevin friction force, when added in the model, strongly affects the short-t CM dynamics which, however, can remain strongly enhanced. The transient VHI effects thus provide the dominant contribution to the subdiffusive CM motion universally observed in simulations and experiments on polymer melts.
Anomalous plasticity in defect-mediated phase transformations
NASA Astrophysics Data System (ADS)
Ghimire, Punam; Ravelo, R.; Germann, T. C.
2014-03-01
Large-scale molecular dynamics simulations of shocked wave propagation in metallic single crystals exhibit high elastic limits and are ideally suited for investigating the role defect nucleation and multiplication play on the kinetics of phase transformations. Here we report on the morphology and kinetics of shocked-induced phase transformations in Aluminum single crystals. The atomic interactions were modeled utilizing various embedded atom method (EAM) models of Aluminum, with most models exhibiting an artificial fcc -->bcc phase transformation in the 25-30 GPa range. For cases where plastic deformation precedes the phase transformation, anomalous defect structures atypical of plastic deformation in bcc lattices nucleate early on but anneal out with time. In all cases, the defect-mediated phase transitions proceed at faster rates than defect-free ones. Part of this work supported by the Air Force Office of Scientific Research under AFOSR Award No. FA9550-12-1-0476.
Search for anomalous Wtb couplings in single top quark production.
Abazov, V M; Abbott, B; Abolins, M; Acharya, B S; Adams, M; Adams, T; Aguilo, E; Ahsan, M; Alexeev, G D; Alkhazov, G; Alton, A; Alverson, G; Alves, G A; Anastasoaie, M; Ancu, L S; Andeen, T; Andrieu, B; Anzelc, M S; Aoki, M; Arnoud, Y; Arov, M; Arthaud, M; Askew, A; Asman, B; Assis Jesus, A C S; Atramentov, O; Avila, C; Badaud, F; Bagby, L; Baldin, B; Bandurin, D V; Banerjee, P; Banerjee, S; Barberis, E; Barfuss, A-F; Bargassa, P; Baringer, P; Barreto, J; Bartlett, J F; Bassler, U; Bauer, D; Beale, S; Bean, A; Begalli, M; Begel, M; Belanger-Champagne, C; Bellantoni, L; Bellavance, A; Benitez, J A; Beri, S B; Bernardi, G; Bernhard, R; Bertram, I; Besançon, M; Beuselinck, R; Bezzubov, V A; Bhat, P C; Bhatnagar, V; Biscarat, C; Blazey, G; Blekman, F; Blessing, S; Bloch, D; Bloom, K; Boehnlein, A; Boline, D; Bolton, T A; Boos, E E; Borissov, G; Bose, T; Brandt, A; Brock, R; Brooijmans, G; Bross, A; Brown, D; Bu, X B; Buchanan, N J; Buchholz, D; Buehler, M; Buescher, V; Bunichev, V; Burdin, S; Burnett, T H; Buszello, C P; Butler, J M; Calfayan, P; Calvet, S; Cammin, J; Carrera, E; Carvalho, W; Casey, B C K; Castilla-Valdez, H; Chakrabarti, S; Chakraborty, D; Chan, K M; Chandra, A; Cheu, E; Chevallier, F; Cho, D K; Choi, S; Choudhary, B; Christofek, L; Christoudias, T; Cihangir, S; Claes, D; Clutter, J; Cooke, M; Cooper, W E; Corcoran, M; Couderc, F; Cousinou, M-C; Crépé-Renaudin, S; Cuplov, V; Cutts, D; Cwiok, M; da Motta, H; Das, A; Davies, G; De, K; de Jong, S J; De La Cruz-Burelo, E; De Oliveira Martins, C; Degenhardt, J D; Déliot, F; Demarteau, M; Demina, R; Denisov, D; Denisov, S P; Desai, S; Diehl, H T; Diesburg, M; Dominguez, A; Dong, H; Dorland, T; Dubey, A; Dudko, L V; Duflot, L; Dugad, S R; Duggan, D; Duperrin, A; Dyer, J; Dyshkant, A; Eads, M; Edmunds, D; Ellison, J; Elvira, V D; Enari, Y; Eno, S; Ermolov, P; Evans, H; Evdokimov, A; Evdokimov, V N; Ferapontov, A V; Ferbel, T; Fiedler, F; Filthaut, F; Fisher, W; Fisk, H E; Fortner, M; Fox, H; Fu, S; Fuess, S; Gadfort, T; Galea, C F; Garcia, C; Garcia-Bellido, A; Gavrilov, V; Gay, P; Geist, W; Gelé, D; Geng, W; Gerber, C E; Gershtein, Y; Gillberg, D; Ginther, G; Gollub, N; Gómez, B; Goussiou, A; Grannis, P D; Greenlee, H; Greenwood, Z D; Gregores, E M; Grenier, G; Gris, Ph; Grivaz, J-F; Grohsjean, A; Grünendahl, S; Grünewald, M W; Guo, F; Guo, J; Gutierrez, G; Gutierrez, P; Haas, A; Hadley, N J; Haefner, P; Hagopian, S; Haley, J; Hall, I; Hall, R E; Han, L; Harder, K; Harel, A; Hauptman, J M; Hauser, R; Hays, J; Hebbeker, T; Hedin, D; Hegeman, J G; Heinson, A P; Heintz, U; Hensel, C; Herner, K; Hesketh, G; Hildreth, M D; Hirosky, R; Hobbs, J D; Hoeneisen, B; Hoeth, H; Hohlfeld, M; Hossain, S; Houben, P; Hu, Y; Hubacek, Z; Hynek, V; Iashvili, I; Illingworth, R; Ito, A S; Jabeen, S; Jaffré, M; Jain, S; Jakobs, K; Jarvis, C; Jesik, R; Johns, K; Johnson, C; Johnson, M; Jonckheere, A; Jonsson, P; Juste, A; Kajfasz, E; Kalk, J M; Karmanov, D; Kasper, P A; Katsanos, I; Kau, D; Kaushik, V; Kehoe, R; Kermiche, S; Khalatyan, N; Khanov, A; Kharchilava, A; Kharzheev, Y M; Khatidze, D; Kim, T J; Kirby, M H; Kirsch, M; Klima, B; Kohli, J M; Konrath, J-P; Kozelov, A V; Kraus, J; Kuhl, T; Kumar, A; Kupco, A; Kurca, T; Kuzmin, V A; Kvita, J; Lacroix, F; Lam, D; Lammers, S; Landsberg, G; Lebrun, P; Lee, W M; Leflat, A; Lellouch, J; Li, J; Li, L; Li, Q Z; Lietti, S M; Lim, J K; Lima, J G R; Lincoln, D; Linnemann, J; Lipaev, V V; Lipton, R; Liu, Y; Liu, Z; Lobodenko, A; Lokajicek, M; Love, P; Lubatti, H J; Luna, R; Lyon, A L; Maciel, A K A; Mackin, D; Madaras, R J; Mättig, P; Magass, C; Magerkurth, A; Mal, P K; Malbouisson, H B; Malik, S; Malyshev, V L; Mao, H S; Maravin, Y; Martin, B; McCarthy, R; Melnitchouk, A; Mendoza, L; Mercadante, P G; Merkin, M; Merritt, K W; Meyer, A; Meyer, J; Millet, T; Mitrevski, J; Mommsen, R K; Mondal, N K; Moore, R W; Moulik, T; Muanza, G S; Mulhearn, M; Mundal, O; Mundim, L; Nagy, E; Naimuddin, M; Narain, M; Naumann, N A; Neal, H A; Negret, J P; Neustroev, P; Nilsen, H; Nogima, H; Novaes, S F; Nunnemann, T; O'Dell, V; O'Neil, D C; Obrant, G; Ochando, C; Onoprienko, D; Oshima, N; Osman, N; Osta, J; Otec, R; Otero y Garzón, G J; Owen, M; Padley, P; Pangilinan, M; Parashar, N; Park, S-J; Park, S K; Parsons, J; Partridge, R; Parua, N; Patwa, A; Pawloski, G; Penning, B; Perfilov, M; Peters, K; Peters, Y; Pétroff, P; Petteni, M; Piegaia, R; Piper, J; Pleier, M-A; Podesta-Lerma, P L M; Podstavkov, V M; Pogorelov, Y; Pol, M-E; Polozov, P; Pope, B G; Popov, A V; Potter, C; Prado da Silva, W L; Prosper, H B; Protopopescu, S; Qian, J; Quadt, A; Quinn, B; Rakitine, A; Rangel, M S; Ranjan, K; Ratoff, P N; Renkel, P; Reucroft, S; Rich, P; Rieger, J; Rijssenbeek, M; Ripp-Baudot, I; Rizatdinova, F; Robinson, S; Rodrigues, R F; Rominsky, M; Royon, C; Rubinov, P; Ruchti, R; Safronov, G; Sajot, G; Sánchez-Hernández, A; Sanders, M P; Sanghi, B; Savage, G; Sawyer, L; Scanlon, T; Schaile, D; Schamberger, R D; Scheglov, Y; Schellman, H; Schliephake, T; Schlobohm, S; Schwanenberger, C; Schwartzman, A; Schwienhorst, R; Sekaric, J; Severini, H; Shabalina, E; Shamim, M; Shary, V; Shchukin, A A; Shivpuri, R K; Siccardi, V; Simak, V; Sirotenko, V; Skubic, P; Slattery, P; Smirnov, D; Snow, G R; Snow, J; Snyder, S; Söldner-Rembold, S; Sonnenschein, L; Sopczak, A; Sosebee, M; Soustruznik, K; Spurlock, B; Stark, J; Steele, J; Stolin, V; Stoyanova, D A; Strandberg, J; Strandberg, S; Strang, M A; Strauss, E; Strauss, M; Ströhmer, R; Strom, D; Stutte, L; Sumowidagdo, S; Svoisky, P; Sznajder, A; Tamburello, P; Tanasijczuk, A; Taylor, W; Tiller, B; Tissandier, F; Titov, M; Tokmenin, V V; Torchiani, I; Tsybychev, D; Tuchming, B; Tully, C; Tuts, P M; Unalan, R; Uvarov, L; Uvarov, S; Uzunyan, S; Vachon, B; van den Berg, P J; Van Kooten, R; van Leeuwen, W M; Varelas, N; Varnes, E W; Vasilyev, I A; Vaupel, M; Verdier, P; Vertogradov, L S; Verzocchi, M; Vilanova, D; Villeneuve-Seguier, F; Vint, P; Vokac, P; Von Toerne, E; Voutilainen, M; Wagner, R; Wahl, H D; Wang, L; Wang, M H L S; Warchol, J; Watts, G; Wayne, M; Weber, G; Weber, M; Welty-Rieger, L; Wenger, A; Wermes, N; Wetstein, M; White, A; Wicke, D; Wilson, G W; Wimpenny, S J; Wobisch, M; Wood, D R; Wyatt, T R; Xie, Y; Yacoob, S; Yamada, R; Yang, W-C; Yasuda, T; Yatsunenko, Y A; Yin, H; Yip, K; Yoo, H D; Youn, S W; Yu, J; Zeitnitz, C; Zelitch, S; Zhao, T; Zhou, B; Zhu, J; Zielinski, M; Zieminska, D; Zieminski, A; Zivkovic, L; Zutshi, V; Zverev, E G
2008-11-28
In 0.9 fb(-1) of pp[over] collisions, the D0 Collaboration presented evidence for single top quark production in events with an isolated lepton, missing transverse momentum, and two to four jets. We examine these data to study the Lorentz structure of the Wtb coupling. The standard model predicts a left-handed vector coupling at the Wtb vertex. The most general lowest dimension, CP-conserving Lagrangian admits right-handed vector and left- or right-handed tensor couplings as well. We find that the data prefer the left-handed vector coupling and set upper limits on the anomalous couplings. These are the first direct constraints on a general Wtb interaction and the first direct limits on left- and right-handed tensor couplings.
Anomalous Decline of Molecular Ion Mobility in Cooled Helium Gas
NASA Astrophysics Data System (ADS)
Ohtsuki, Kazumasa; Hananoe, Masatoshi; Matsuzawa, Michio
2005-11-01
We present a first successful theoretical account of the ion mobilities of N2+ and O2+ in helium gas at 4.3 K. Measured mobilities of various molecular ions at low effective temperatures reportedly tend to values smaller than their polarization limits, with the exception of N2+ [J. Sanderson , J. Phys. BJPAPEH0953-4075 26, L465 (1993)10.1088/0953-4075/26/15/006; J. SandersonJ. Phys. BJPAPEH0953-407527, L433 (1994)10.1088/0953-4075/27/14/021]. The present theoretical results obtained by the classical trajectory calculations agree with the experimental ones very well, and make it definitive that the anomalous decline of molecular ion mobility is caused by a Feshbach-like resonance due to the anisotropic interaction potential between a molecular ion and a helium atom. The mechanism thus revealed is supported by quantitative quantum mechanical calculations. The process appears very similar to that of laser cooling.
Anomalous magnetization of a carbon nanotube as an excitonic insulator
NASA Astrophysics Data System (ADS)
Rontani, Massimo
2014-11-01
We show theoretically that an undoped carbon nanotube might be an excitonic insulator—the long-sought phase of matter proposed by Keldysh, Kohn, and others fifty years ago. We predict that the condensation of triplet excitons, driven by intervalley exchange interaction, spontaneously occurs at equilibrium if the tube radius is sufficiently small. The signatures of exciton condensation are its sizable contributions to both the energy gap and the magnetic moment per electron. The increase of the gap might have already been measured, albeit with a different explanation [V. V. Deshpande, B. Chandra, R. Caldwell, D. S. Novikov, J. Hone, and M. Bockrath, Science 323, 106 (2009), 10.1126/science.1165799]. The enhancement of the quasiparticle magnetic moment is a pair-breaking effect that counteracts the weak paramagnetism of the ground-state condensate of excitons. This property could rationalize the anomalous magnitude of magnetic moments recently observed in different devices close to charge neutrality.
Characterizing cosmic inhomogeneity with anomalous diffusion
NASA Astrophysics Data System (ADS)
Kraljic, D.
2015-08-01
Dark matter (DM) clustering at the present epoch is investigated from a fractal viewpoint in order to determine the scale where the self-similar scaling property of the DM halo distribution transits to homogeneity. Methods based on well-established `counts-in-cells' as well as new methods based on anomalous diffusion and random walks are investigated. Both are applied to DM haloes of the biggest N-body simulation in the `Dark Sky Simulations' (DS) catalogue and an equivalent randomly distributed catalogue. Results based on the smaller `Millennium Run' (MR) simulation are revisited and improved. It is found that the MR simulation volume is too small and prone to bias to reliably identify the onset of homogeneity. Transition to homogeneity is defined when the fractal dimension of the clustered and random distributions cannot be distinguished within the associated uncertainties. The `counts-in-cells' method applied to the DS then yields a homogeneity scale roughly consistent with previous work (˜150 h-1 Mpc). The characteristic length-scale for anomalous diffusion to behave homogeneously is found to be at about 250 h-1 Mpc. The behaviour of the fractal dimensions for a halo catalogue with the same two-point function as the original but with shuffled Fourier phases is investigated. The methods based on anomalous diffusion are shown to be sensitive to the phase information, whereas the `counts-in-cells' methods are not.
Anomalous and resonance small angle scattering: Revision
Epperson, J.E.; Thiyagarajan, P.
1987-11-01
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 considering 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 analogue 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 scatterings are discussed. 54 refs., 8 figs., 1 tab.
Anomalous and resonance small angle scattering
Epperson, J.E.; Thiyagarajan, P.
1987-11-01
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 considering 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 or the analogue 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 scatterings are discussed. 8 figs.
Neoclassical and anomalous flows in stellarators
NASA Astrophysics Data System (ADS)
Ware, A. S.; Marine, T.; Spong, D. A.
2009-11-01
The impact of magnetic geometry and plasma profiles on flows and viscosities in stellarators is investigated. This work examines both neoclassical and anomalous flows for a number of configurations including a particular focus on the Helically Symmetric Experiment (HSX) and other quasi-symmetric configurations. Neoclassical flows and viscosities are calculated using the PENTA code [1]. For anomalous flows, the neoclassical viscosities from PENTA are used in a transport code that includes Reynolds stress flow generation [2]. This is done for the standard quasi-helically symmetric configuration of HSX, a symmetry-breaking mirror configuration and a hill configuration. The impact of these changes in the magnetic geometry on neoclassical viscosities and flows in HSX are discussed. Due to variations in neoclassical viscosities, HSX can have strong neoclassical flows in the core region. In turn, these neoclassical flows can provide a seed for anomalous flow generation. These effects are shown to vary as the ratio of electron to ion temperature varies. In particular, as the ion temperature increases relative to the electron flow shear is shown to increase. [1] D. A. Spong, Phys. Plasmas 12, 056114 (2005). [2] D. E. Newman, et al., Phys. Plasmas 5, 938 (1998).
Crossover to the anomalous quantum regime in the extrinsic spin Hall effect of graphene
NASA Astrophysics Data System (ADS)
Milletarı, Mirco; Ferreira, Aires
2016-11-01
Recent reports of spin-orbit coupling enhancement in chemically modified graphene have opened doors to studies of the spin Hall effect with massless chiral fermions. Here, we theoretically investigate the interaction and impurity density dependence of the extrinsic spin Hall effect in spin-orbit coupled graphene. We present a nonperturbative quantum diagrammatic calculation of the spin Hall response function in the strong-coupling regime that incorporates skew scattering and anomalous impurity density-independent contributions on equal footing. The spin Hall conductivity dependence on Fermi energy and electron-impurity interaction strength reveals the existence of experimentally accessible regions where anomalous quantum processes dominate. Our findings suggest that spin-orbit-coupled graphene is an ideal model system for probing the competition between semiclassical and bona fide quantum scattering mechanisms underlying the spin Hall effect.
Anomalous transmission of an ultrashort ionizing laser pulse through a thin foil.
Ferrante, G; Zarcone, M; Uryupin, S A
2003-08-22
The formation of a highly anisotropic photoelectron velocity distribution as a result of the interaction of a powerful ultrashort laser pulse with a thin foil is found to yield a large skin-layer depth and an anomalous increase of the transmission coefficient. The physical reason for the effect is the influence of the incident wave magnetic field, through the Lorenz force, on the electron kinetics in the skin layer.
Anomalous Josephson Hall effect in magnet/triplet superconductor junctions
NASA Astrophysics Data System (ADS)
Yokoyama, Takehito
2015-11-01
We investigate anomalous Hall effect in a magnet coupled to a triplet superconductor under phase gradient. It is found that the anomalous Hall supercurrent arises from the nontrivial structure of the magnetization. The magnetic structure manifested in the Hall supercurrent is characterized by even order terms of the exchange coupling, essentially different from that discussed in the context of anomalous Hall effect, reflecting the dissipationless nature of the supercurrent. We also discuss a possible candidate for magnetic structure to verify our prediction.
Tellurium - Should it be isotopically anomalous in the Allende meteorite
NASA Technical Reports Server (NTRS)
Heymann, D.; Dziczkaniec, M.
1981-01-01
Isotopically anomalous Te is a by-product of the nuclear processes in zones of supernovae that have been proposed as sources for isotopically anomalous Xe. The calculated composition of the anomalous Te is roughly consistent with the disputed measurements made by Ballad et at. (1979) and Oliver et al. (1979) of samples of the Allende meteorite, with the exception that the large Te-123 overabundance reported by Oliver et al. (1979) is not predicted by the theory.
Spectral analysis of the multiple-altitude anomalous geomagnetic field
NASA Astrophysics Data System (ADS)
Tsvetkov, Yu. P.; Ivanov, V. V.; Petrov, V. G.; Filippov, S. V.; Brekhov, O. M.
2016-11-01
The spectra of the anomalous geomagnetic field measured at ground and balloon (30 km) altitudes were analyzed. The ground-based data were adapted from a map of the anomalous magnetic field of the Earth. A balloon surveys was carried out by the authors. It has been shown that the ground and balloon spectra of the anomalous magnetic field of the Earth substantially differ. Suppositions explaining the differences in the obtained spectra have been suggested.
Scaling theory for anomalous semiclassical quantum transport
NASA Astrophysics Data System (ADS)
Sena-Junior, M. I.; Macêdo, A. M. S.
2016-01-01
Quantum transport through devices coupled to electron reservoirs can be described in terms of the full counting statistics (FCS) of charge transfer. Transport observables, such as conductance and shot-noise power are just cumulants of FCS and can be obtained from the sample's average density of transmission eigenvalues, which in turn can be obtained from a finite element representation of the saddle-point equation of the Keldysh (or supersymmetric) nonlinear sigma model, known as quantum circuit theory. Normal universal metallic behavior in the semiclassical regime is controlled by the presence of a Fabry-Pérot singularity in the average density of transmission eigenvalues. We present general conditions for the suppression of Fabry-Pérot modes in the semiclassical regime in a sample of arbitrary shape, a disordered conductor or a network of ballistic quantum dots, which leads to an anomalous metallic phase. Through a double-scaling limit, we derive a scaling equation for anomalous metallic transport, in the form of a nonlinear differential equation, which generalizes the ballistic-diffusive scaling equation of a normal metal. The two-parameter stationary solution of our scaling equation generalizes Dorokhov's universal single-parameter distribution of transmission eigenvalues. We provide a simple interpretation of the stationary solution using a thermodynamic analogy with a spin-glass system. As an application, we consider a system formed by a diffusive wire coupled via a barrier to normal-superconductor reservoirs. We observe anomalous reflectionless tunneling, when all perfectly transmitting channels are suppressed, which cannot be explained by the usual mechanism of disorder-induced opening of tunneling channels.
An "anomalous" triggered lightning flash in Florida
NASA Astrophysics Data System (ADS)
Gamerota, W. R.; Uman, M. A.; Hill, J. D.; Pilkey, J.; Ngin, T.; Jordan, D. M.; Mata, C. T.
2013-04-01
An "anomalous" rocket-and-wire triggered lightning flash, a flash whose leaders do not follow the triggering wire remnants to ground, is characterized via high-speed video images at 10 and 300 kilo-frames per second, still camera images, 66-72 MHz source locations from a Lightning Mapping Array, channel-base current, and electric field and electric field derivative (dE/dt) measurements. This is the first anomalous flash of about 410 classically triggered flashes in north-central Florida. The flash began with an upward positively charged leader (UPL) initiating from the tip of the upward-moving triggering wire about 280 m above ground level. All but the bottom 17 m of wire exploded (became luminous) 37.6 ms after UPL initiation. A stepped leader initiated, likely from the top of the wire remnants, 282 m above ground level about 1.3 ms after the wire explosion and propagated downward for 2.1 ms, attaching to the top of a grounded utility pole 117 m southwest of the launching facility. The line charge density on the stepped leader is estimated to be of the order of 10-3 C m-1. Contrary to previously reported "anomalous" flashes in France and New Mexico (roughly 16% and 31%, respectively, of their triggered flashes), in our event, there was not a tens of milliseconds current-zero period preceding the stepped leader, there was no observed downward dart leader in the UPL channel prior to the stepped leader to ground, and there was a failed attempt to reestablish current in the exploded-wire channel between the UPL and ground.
Interpreting anomalous magnetic fabrics in ophiolite dikes
NASA Astrophysics Data System (ADS)
Borradaile, G. J.; Gauthier, D.
2003-02-01
Anisotropy of magnetic susceptibility (AMS) may reveal mineral orientation-distributions defining magmatic flow-axes in igneous dikes. The mafic silicates are the best indication of magmatic flow but Fe-Ti accessories may contribute more to the bulk susceptibility. If the orientation-distributions of the two subfabrics are incongruent, anomalous fabrics will occur that do not reflect magma-flow axes. For ophiolite dikes, ocean-floor metamorphism changes the mineralogy producing new Fe-oxides by retrogression and exsolution from mafic silicates and by the oxidation of primary oxides. Incompatibly oriented 'ferro'-magnetic subfabrics may be isolated by anisotropy of anhysteretic remanence (AARM). Anomalous AMS fabrics in ophiolites elsewhere have been attributed to inverse-fabric contributions from single-domain magnetite in varying combinations. However, in ophiolite dikes from the Troodos ophiolite of Cyprus, anomalous fabrics arise from ocean-floor metamorphism extensively or completely replacing the original magnetite and titanomagnetite accessory phases with titanomagnetite (˜Fe 2.4Ti 0.6O 4=TM60) and its oxidised versions, titanomaghemite, to varying degrees according to depth beneath the ocean-floor, distance from spreading axis and proximity to transform-faults. At best, the oxide orientation-distribution defined by AARM could only be indirectly related to magma-flow if its nucleation-orientation controlled by a host-lattice. However, more commonly the topotactic lattice reorganization produces weaker ARM fabric anisotropies. Although 'recrystallized', oxidised TM60 dominates the bulk low-field susceptibility, its anisotropy is generally too feeble to compete with the flow-fabric defined by the AMS contribution from paramagnetic mafic silicates.
Quartz: Anomalous Weakness of Synthetic Crystals.
Griggs, D T; Blacic, J D
1965-01-15
The strength of a synthetic quartz crystal drops rapidly at 400 degrees C, and at 600 degrees C is a hundredfold lower than at 300 degrees C. Large plastic deformations can be produced without fracture. The predominant mechanism of deformation is translation gliding. The preferred explanation for this anomalous weakness is that this synthetic quartz contains water which has hydrolyzed the silicon-oxygen bonds. The silanol groups so formed are presumed to be rendered sufficiently mobile by elevating the temperature to 400 degrees C so that they align themselves in dislocation lines and move through the crystal with the dislocation under the small applied shear stress.
Anomalous-scattering region on Triton
NASA Technical Reports Server (NTRS)
Lee, Pascal; Helfenstein, Paul; Veverka, Joseph; Mccarthy, Derek
1992-01-01
A photometric analysis of Voyager 2 images of a broad, 'anomalous scattering region' (ASR) on Triton shows its material to differ from the average Triton regolith in being only weakly backward scattering at all Voyager 2 camera wavelengths; the ASR also displays distinctive phase-dependent green/violet color ratios and clear-filter albedo. These characteristics are used to map the global distribution of the ASR areas for which photometric coverage is incomplete. The ASR may form an almost continuous band of material that runs parallel to the Triton equator, characterized by the presence of a transparent and optically thin, seasonally-controlled veneer of well-annealed solid N2.
Anomalous transport modelling of tokamak plasmas
Kinsey, J.; Singer, C.; Malone, G.; Tiouririne, N.
1992-12-31
Theory based transport simulations of DIII-D, JET, ITER are compared to experimental data using a combination of anamolous transport models. The Multiple-mode Transport Model is calibrated to a give set of L-mode and H-mode discharges with an emphasis on testing the adequacy of anomalous flux contributions from drift/{eta}{sub i} and resistive ballooning mode theories. A survey of possible additions and/or alternatives to the model from recent theories on neoclassical MHD effects, hot ion modes, circulating electron modes, and high-m tearing modes is also included.
Anomalous transport modelling of tokamak plasmas
Kinsey, J.; Singer, C.; Malone, G.; Tiouririne, N.
1992-01-01
Theory based transport simulations of DIII-D, JET, ITER are compared to experimental data using a combination of anamolous transport models. The Multiple-mode Transport Model is calibrated to a give set of L-mode and H-mode discharges with an emphasis on testing the adequacy of anomalous flux contributions from drift/[eta][sub i] and resistive ballooning mode theories. A survey of possible additions and/or alternatives to the model from recent theories on neoclassical MHD effects, hot ion modes, circulating electron modes, and high-m tearing modes is also included.
Anomalous Dynamical Behavior of Freestanding Graphene Membranes
NASA Astrophysics Data System (ADS)
Ackerman, M. L.; Kumar, P.; Neek-Amal, M.; Thibado, P. M.; Peeters, F. M.; Singh, Surendra
2016-09-01
We report subnanometer, high-bandwidth measurements of the out-of-plane (vertical) motion of atoms in freestanding graphene using scanning tunneling microscopy. By tracking the vertical position over a long time period, a 1000-fold increase in the ability to measure space-time dynamics of atomically thin membranes is achieved over the current state-of-the-art imaging technologies. We observe that the vertical motion of a graphene membrane exhibits rare long-scale excursions characterized by both anomalous mean-squared displacements and Cauchy-Lorentz power law jump distributions.
Extraordinary Hall effect in Kondo-type systems: Contributions from anomalous velocity
NASA Astrophysics Data System (ADS)
Levy, P. M.
1988-10-01
Kondo systems exhibit a relatively large extraordinary Hall effect which is due to asymmetric resonant scattering of conduction electrons. Theories based on the skew scattering mechanism account for data at high temperatures T>TK (the Kondo temperature) but are unable to explain the very-low-temperature variation of the Hall constant observed in heavy-fermion compounds. Aside from the ordinary Hall effect, caused by the Lorentz force and skew scattering (which makes the scattering probability antisymmetric with respect to interchange of scattering vectors), there exists an additional contribution to the Hall effect known as the anomalous-velocity contribution. This contribution is due to a change in the expression for the current operator in the presence of spin-orbit forces. We derive an expression for the anomalous velocity in terms of the T matrices describing conduction-electron scattering; it is not limited to weak spin-orbit scattering as were previous results. We use the Anderson model of local moments in metals to write this scattering in terms of the mixing interaction between local and conduction electrons, and the local state's Green's function. The transverse Hall current due to anomalous velocity is determined and evaluated in two limits. At high temperature, we use the weak-coupling form of the local state's Green's function; at T=0 K a phase-shift analysis is used, and we rely on the Friedel-Langreth sum rule to give us the phase shift at the Fermi surface. At high temperatures we find that the contribution from anomalous velocity to the Hall constant is quite small compared to that from skew scattering. On the contrary, at low temperatures the anomalous velocity makes the dominant contribution to the Hall constant in Kondo systems.
Li, Zhongyang; Palacios, Edgar; Butun, Serkan; Aydin, Koray
2015-03-11
Ultrathin metasurfaces have recently emerged as promising materials that have huge potential to enable novel, flat optical components, and surface-confined, miniature photonic devices. Metasurfaces offer new degrees of freedom in molding the optical wavefronts by introducing abrupt and drastic changes in the amplitude, phase, and/or polarization of electromagnetic radiation at the wavelength scale. By carefully arranging multiple subwavelength anisotropic or gradient optical resonators, metasurfaces have been shown to enable anomalous transmission, anomalous reflection, optical holograms, and spin-orbit interaction. However, experimental realization of high-performance metasurfaces that can operate at visible frequency range has been a significant challenge due to high optical losses of plasmonic materials and difficulties in fabricating several plasmonic resonators of subwavelength size with high uniformity. Here, we propose a highly efficient yet a simple metasurface design comprising of a single, anisotropic silver antenna in its unit cell. We demonstrate broadband (450-850 nm) anomalous reflection and spectrum splitting at visible and near-IR frequencies with high conversion efficiency. Average power ratio of anomalous reflection to the strongest diffraction mode was calculated to be on the order of 10(3) and measured to be on the order of 10. The anomalous reflected photons have been visualized using a charge-coupled device camera, and broadband spectrum splitting performance has been confirmed experimentally using a free space, angle-resolved reflection measurement setup. Metasurface design proposed in this study is a clear departure from conventional metasurfaces utilizing multiple, anisotropic and/or gradient optical resonators and could enable high-efficiency, broadband metasurfaces for achieving flat high signal-to-noise ratio optical spectrometers, polarization beam splitters, directional emitters, and spectrum splitting surfaces for photovoltaics.
Anomalous Micellization of Pluronic Block Copolymers
NASA Astrophysics Data System (ADS)
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 Enthalpy Relaxation in Vitreous Silica
NASA Astrophysics Data System (ADS)
Yue, Yuanzheng
2015-08-01
It is a challenge to calorimetrically determine the glass transition temperature (Tg) of vitreous silica. Here we demonstrate that this challenge mainly arises from the extreme sensitivity of the Tg to the hydroxyl content in vitreous silica, but also from the irreversibility of its glass transition when repeating the calorimetric 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 hperquenching-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 event diagnosis for environmental satellite systems
NASA Technical Reports Server (NTRS)
Ramsay, Bruce H.
1993-01-01
The National Oceanic and Atmospheric Administration's (NOAA) National Environmental Satellite, Data, and Information Service (NESDIS) is responsible for the operation of the NOAA geostationary and polar orbiting satellites. NESDIS provides a wide array of operational meteorological and oceanographic products and services and operates various computer and communication systems on a 24-hour, seven days per week schedule. The Anomaly Reporting System contains a database of anomalous events regarding the operations of the Geostationary Operational Environmental Satellite (GOES), communication, or computer systems that have degraded or caused the loss of GOES imagery. Data is currently entered manually via an automated query user interface. There are 21 possible symptoms (e.g., No Data), and 73 possible causes (e.g., Sectorizer - World Weather Building) of an anomalous event. The determination of an event's cause(s) is made by the on-duty computer operator, who enters the event in a paper based daily log, and by the analyst entering the data into the reporting system. The determination of the event's cause(s) impacts both the operational status of these systems, and the performance evaluation of the on-site computer and communication operations contractor.
Anomalous piezoresistance effect in ultrastrained silicon nanowires.
Lugstein, A; Steinmair, M; Steiger, A; Kosina, H; Bertagnolli, E
2010-08-11
In this paper we demonstrate that under ultrahigh strain conditions p-type single crystal silicon nanowires possess an anomalous piezoresistance effect. The measurements were performed on vapor-liquid-solid (VLS) grown Si nanowires, monolithically integrated in a microelectro-mechanical loading module. The special setup enables the application of pure uniaxial tensile strain along the <111> growth direction of individual, 100 nm thick Si nanowires while simultaneously measuring the resistance of the nanowires. For low strain levels (nanowire elongation less than 0.8%), our measurements revealed the expected positive piezoresistance effect, whereas for ultrahigh strain levels a transition to anomalous negative piezoresistance was observed. For the maximum tensile strain of 3.5%, the resistance of the Si nanowires decreased by a factor of 10. Even at these high strain amplitudes, no fatigue failures are observed for several hundred loading cycles. The ability to fabricate single-crystal nanowires that are widely free of structural defects will it make possible to apply high strain without fracturing to other materials as well, therefore in any application where crystallinity and strain are important, the idea of making nanowires should be of a high value.
Anomalous segregation dynamics of self-propelled particles
Mones, Enys; Czirók, András; Vicsek, Tamás
2015-01-01
A number of novel experimental and theoretical results have recently been obtained on active soft matter, demonstrating the various interesting universal and anomalous features of this kind of driven systems. Here we consider the adhesion difference-driven segregation of actively moving units, a fundamental but still poorly explored aspect of collective motility. In particular, we propose a model in which particles have a tendency to adhere through a mechanism which makes them both stay in touch and synchronize their direction of motion – but the interaction is limited to particles of the same kind. The calculations corresponding to the related differential equations can be made in parallel, thus a powerful GPU card allows large scale simulations. We find that in a very large system of particles, interacting without explicit alignment rule, three basic segregation regimes seem to exist as a function of time: i) at the beginning the time dependence of the correlation length is analogous to that predicted by the Cahn-Hillard theory, ii) next rapid segregation occurs characterized with a separation of the different kinds of units being faster than any previously suggested speed, finally, iii) the growth of the characteristic sizes in the system slows down due to a new regime in which self-confined, rotating, splitting and re-joining clusters appear. Our results can explain recent observations of segregating tissue cells in vitro. PMID:26478713
Anomalous segregation dynamics of self-propelled particles
NASA Astrophysics Data System (ADS)
Mones, Enys; Czirók, András; Vicsek, Tamás
2015-06-01
A number of novel experimental and theoretical results have recently been obtained on active soft matter, demonstrating the various interesting universal and anomalous features of this kind of driven systems. Here we consider the adhesion difference-driven segregation of actively moving units, a fundamental but still poorly explored aspect of collective motility. In particular, we propose a model in which particles have a tendency to adhere through a mechanism which makes them both stay in touch and synchronize their direction of motion—but the interaction is limited to particles of the same kind. The calculations corresponding to the related differential equations can be made in parallel, thus a powerful GPU card allows large scale simulations. We find that in a very large system of particles, interacting without explicit alignment rule, three basic segregation regimes seem to exist as a function of time: (i) at the beginning the time dependence of the correlation length is analogous to that predicted by the Cahn-Hilliard theory, (ii) next rapid segregation occurs characterized with a separation of the different kinds of units being faster than any previously suggested speed, finally, (iii) the growth of the characteristic sizes in the system slows down due to a new regime in which self-confined, rotating, splitting and re-joining clusters appear. Our results can explain recent observations of segregating tissue cells in vitro.
Theory of Ramsey spectroscopy and anomalous segregation in ultracold rubidium
NASA Astrophysics Data System (ADS)
Bradley, A. S.; Gardiner, C. W.
2002-10-01
The recent anomalous segregation experiment (Lewandowski H J, Harber D M, Whitaker D L and Cornell E A 2002 Phys. Rev. Lett. 88 070403) shows dramatic, rapid internal state segregation for two hyperfine levels of 87Rb. We simulate an effective one-dimensional model of the system for experimental parameters and find reasonable agreement with the data. The Ramsey frequency is found to be insensitive to the decoherence of the superposition, and is only equivalent to the interaction energy shift for a pure superposition. A quantum Boltzmann equation describing collisions is derived using quantum kinetic theory, taking into account the different scattering lengths of the internal states. As spin-wave experiments are likely to be attempted at lower temperatures we examine the effect of degeneracy on decoherence by considering the recent experiment, where degeneracy is around 10%. We also find that the segregation effect is only possible when transport terms are included in the equations of motion, and that the interactions only directly alter the momentum distributions of the states. The segregation or spin-wave effect is thus entirely due to coherent atomic motion as foreseen by Lewandowski et al.
Bootstrapping Rapidity Anomalous Dimensions for Transverse-Momentum Resummation
Li, Ye; Zhu, Hua Xing
2017-01-01
Soft function relevant for transverse-momentum resummation for Drell-Yan or Higgs production at hadron colliders are computed through to three loops in the expansion of strong coupling, with the help of bootstrap technique and supersymmetric decomposition. The corresponding rapidity anomalous dimension is extracted. An intriguing relation between anomalous dimensions for transverse-momentum resummation and threshold resummation is found.
Bootstrapping Rapidity Anomalous Dimensions for Transverse-Momentum Resummation
NASA Astrophysics Data System (ADS)
Li, Ye; Zhu, Hua Xing
2017-01-01
A soft function relevant for transverse-momentum resummation for Drell-Yan or Higgs production at hadron colliders is computed through to three loops in the expansion of strong coupling, with the help of the bootstrap technique and supersymmetric decomposition. The corresponding rapidity anomalous dimension is extracted. An intriguing relation between anomalous dimensions for transverse-momentum resummation and threshold resummation is found.
Anomalous cosmic ray studies using the geomagnetic field
Mewaldt, R. A.; Cummings, J. R.; Leske, R. A.; Selesnick, R. S.; Stone, E. C.; Rosenvinge, T. T. von
1996-07-20
We use instrumentation on SAMPEX and the Earth's field as a magnetic filter, to obtain a 'pure' sample of anomalous cosmic rays. The energy spectrum of anomalous oxygen is found to extend to {approx}100 MeV/nuc, which has implications for models of the acceleration of these nuclei.
Collective modes of a one-dimensional trapped Bose gas in the presence of the anomalous density
NASA Astrophysics Data System (ADS)
Boudjemâa, Abdelâali
2016-11-01
We study the collective modes of a one-dimensional harmonically trapped Bose-Einstein condensate in the presence of the anomalous density using the time-dependent Hartree-Fock-Bogoliubov theory. Within the hydrodynamic equations, we derive analytical expressions for the mode frequencies and the density fluctuations of the anomalous density which constitutes the minority component at very low temperature and feels an effective external potential exerted by the majority component, i.e., the condensate. On the other hand, we numerically examine the temperature dependence of the breathing mode oscillations of the condensate at finite temperature in the weak-coupling regime. At zero temperature, we compare our predictions with available experimental data, theoretical treatments, and Monte carlo simulations in all interaction regimes and the remaining hindrances are emphasized. We show that the anomalous correlations have a non-negligible role on the collective modes at both zero and finite temperatures.
Modeling Anomalous Crustal Accretion at Spreading Zones
NASA Astrophysics Data System (ADS)
Schmeling, H.; Marquart, G.
2003-12-01
The thermal and seismic structure of normal oceanic crust or anomalous crust such as Iceland depends on the mode of melt extraction from the mantle and its emplacement within or on top of the crust. We model crustal accretion by a two fold approach. In a 2D spreading model with anomalous mantle temperature beneath the ridge we solve the Navier-Stokes-, the heat tansport, the mass conservation and the melting equations to determine the enhanced melt production beneath the ridge. This melt is extracted and emplaced on top of the model to form the crust. Two cases are distinguished: a) Extruded crustal material is taken out of the model and is only advected according to the spreading of the plate, b) extruded material is fed back into the model from the top to mimic isostatic subsidence of extruded crust. We find that the feed back of case b) is only moderate. For example, if extruded crustal material as thick as 40 km is fed back into the model, the melting region is depressed downward only by as much as 10km, and the total amount of generated melt is reduced by about 20 %. On the other hand, the upper 30 km of the model is cooled considerably by several 100 degrees. A second set of models focuses on the details of crustal accretion without explicitly solving for the melting and extraction. Knowing the spreading rate, the rate of crustal production can be estimated, but the site of emplacement is not obvious. For an anomalous crust such as Iceland we define four source regions of crustal accretion: surface extrusion, intrusion in fissure swarms at shallow depth connected to volcanic centres, magma chambers at shallow to mid-crustal level, and a deep accretion zone, where crust is produced by widespread dyke and sill emplacement and underplating. We solve the Navier-Stokes-, the heat tansport and the mass conservation equations and prescribe different functions in space and time for crustal production in the four defined regions. The temperature of the imposed
Tunable anomalous Andreev reflection and triplet pairings in spin-orbit-coupled graphene
NASA Astrophysics Data System (ADS)
Beiranvand, Razieh; Hamzehpour, Hossein; Alidoust, Mohammad
2016-09-01
We theoretically study scattering process and superconducting triplet correlations in a graphene junction comprised of ferromagnet-RSO-superconductor in which RSO stands for a region with Rashba spin-orbit interaction. Our results reveal spin-polarized subgap transport through the system due to an anomalous equal-spin Andreev reflection in addition to conventional backscatterings. We calculate equal- and opposite-spin pair correlations near the F-RSO interface and demonstrate direct link of the anomalous Andreev reflection and equal-spin pairings arisen due to the proximity effect in the presence of RSO interaction. Moreover, we show that the amplitude of anomalous Andreev reflection, and thus the triplet pairings, are experimentally controllable when incorporating the influences of both tunable strain and Fermi level in the nonsuperconducting region. Our findings can be confirmed by a conductance spectroscopy experiment and may provide more insights into the proximity-induced RSO coupling in graphene layers reported recently in experiments [A. Avsar et al., Nat. Commun. 5, 4875 (2014), 10.1038/ncomms5875; Z. Wang et al., Phys. Rev. Lett. 114, 016603 (2015), 10.1103/PhysRevLett.114.016603; J. B. S. Mendes et al., Phys. Rev. Lett. 115, 226601 (2015), 10.1103/PhysRevLett.115.226601; S. Dushenko et al., Phys. Rev. Lett. 116, 166102 (2016), 10.1103/PhysRevLett.116.166102].
On the quantum mechanics of consciousness, with application to anomalous phenomena
Jahn, R.G.; Dunne, B.J.
1986-08-01
Theoretical explication of a growing body of empirical data on consciousness-related anomalous phenomena is unlikely to be achieved in terms of known physical processes. Rather, it will first be necessary to formulate the basic role of consciousness in the definition of reality before such anomalous experience can adequately be represented. This paper takes the position that reality is constituted only in the interaction of consciousness with its environment, and therefore that any scheme of conceptual organization developed to represent that reality must reflect the processes of consciousness as well as those of its environment. In this spirit, the concepts and formalisms of elementary quantum mechanics, as originally proposed to explain anomalous atomic-scale physical phenomena, are appropriated via metaphor to represent the general characteristics of consciousness interacting with any environment. More specifically, if consciousness is represented by a quantum mechanical wave function, and its environment by an appropriate potential profile, Schrodinger wave mechanics defines eigenfunctions and eigenvalues that can be associated with the cognitive and emotional experiences of that consciousness in that environment. To articulate this metaphor it is necessary to associate certain aspects of the formalism, such as the coordinate system, the quantum numbers, and even the metric itself, with various impressionistic descriptors of consciousness, such as its intensity, perspective, approach/avoidance attitude, balance between cognitive and emotional activity, and receptive/assertive disposition.
#FluxFlow: Visual Analysis of Anomalous Information Spreading on Social Media.
Zhao, Jian; Cao, Nan; Wen, Zhen; Song, Yale; Lin, Yu-Ru; Collins, Christopher
2014-12-01
We present FluxFlow, an interactive visual analysis system for revealing and analyzing anomalous information spreading in social media. Everyday, millions of messages are created, commented, and shared by people on social media websites, such as Twitter and Facebook. This provides valuable data for researchers and practitioners in many application domains, such as marketing, to inform decision-making. Distilling valuable social signals from the huge crowd's messages, however, is challenging, due to the heterogeneous and dynamic crowd behaviors. The challenge is rooted in data analysts' capability of discerning the anomalous information behaviors, such as the spreading of rumors or misinformation, from the rest that are more conventional patterns, such as popular topics and newsworthy events, in a timely fashion. FluxFlow incorporates advanced machine learning algorithms to detect anomalies, and offers a set of novel visualization designs for presenting the detected threads for deeper analysis. We evaluated FluxFlow with real datasets containing the Twitter feeds captured during significant events such as Hurricane Sandy. Through quantitative measurements of the algorithmic performance and qualitative interviews with domain experts, the results show that the back-end anomaly detection model is effective in identifying anomalous retweeting threads, and its front-end interactive visualizations are intuitive and useful for analysts to discover insights in data and comprehend the underlying analytical model.
Probing anomalous Higgs couplings in H → ZV decays
NASA Astrophysics Data System (ADS)
Modak, Tanmoy; Srivastava, Rahul
2017-01-01
We analyze the possibility of probing anomalous Higgs couplings in the rare decays H → ZV, V being a vector quarkonium state. These rare decays involve both gauge as well as the Yukawa sectors and either of them can potentially be anomalous. We show that the branching fractions for H → ZV decays in Standard Model (SM) are small, making it a sensitive probe for anomalous Higgs couplings originating from physics beyond SM. Moreover, as both V and Z can decay into pair of charged leptons, they provide experimentally clean channels and future LHC runs should observe such decays. We perform a model independent analysis and show how angular asymmetries can be used to probe these anomalous Higgs couplings, taking further decays of V and Z to pair of charged leptons into account. The angular asymmetries can provide significant information about anomalous Higgs couplings in both gauge and Yukawa sectors.
Anomalous Evidence, Confidence Change, and Theory Change.
Hemmerich, Joshua A; Van Voorhis, Kellie; Wiley, Jennifer
2016-08-01
A novel experimental paradigm that measured theory change and confidence in participants' theories was used in three experiments to test the effects of anomalous evidence. Experiment 1 varied the amount of anomalous evidence to see if "dose size" made incremental changes in confidence toward theory change. Experiment 2 varied whether anomalous evidence was convergent (of multiple types) or replicating (similar finding repeated). Experiment 3 varied whether participants were provided with an alternative theory that explained the anomalous evidence. All experiments showed that participants' confidence changes were commensurate with the amount of anomalous evidence presented, and that larger decreases in confidence predicted theory changes. Convergent evidence and the presentation of an alternative theory led to larger confidence change. Convergent evidence also caused more theory changes. Even when people do not change theories, factors pertinent to the evidence and alternative theories decrease their confidence in their current theory and move them incrementally closer to theory change.
Anomalous bond length behavior and a new solid phase of bromine under pressure
Wu, Min; Tse, John S.; Pan, Yuanming
2016-01-01
The behavior of diatomic molecular solids under pressure have attracted great interest and been extensively studied. Under ambient pressure, the structure of bromine is known to be a molecular phase (phase I). With increasing pressure, it transforms into an incommensurate phase (phase V) before eventually to a monoatomic phase (phase II). However, between phases I and V, the interatomic distance was found to first increase with pressure and then decreased abruptly. This anomalous bond length behavior is accompanied by the splitting of the Raman bands. These phenomena have not been resolved. Here we suggest a new solid phase that explains the Raman spectra. Furthermore, the anomalous bond length behavior is found to be the result of subtle second neighbor intermolecular interactions and is an intrinsic property of bromine in molecular phases. PMID:27156710
Following fluctuating signs: Anomalous active superdiffusion of swimmers in anisotropic media.
Toner, John; Löwen, Hartmut; Wensink, Henricus H
2016-06-01
Active (i.e., self-propelled or swimming) particles moving through an isotropic fluid exhibit conventional diffusive behavior. We report anomalous diffusion of an active particle moving in an anisotropic nematic background. While the translational motion parallel to the nematic director shows ballistic behavior, the long-time transverse motion is superdiffusive, with an anomalous scaling proportional to tlnt of the mean-square displacement with time t. This behavior is predicted by an analytical theory that we present here and is corroborated by numerical simulation of active particle diffusion in a simple lattice model for a nematic liquid crystal. It is universal for any collection of self-propelled elements (e.g., bacteria or active rods) moving in a nematic background, provided only that the swimmers are sufficiently dilute that their interactions with each other can be neglected and that they do not perform hairpin turns.
Resistively detected NMR in quantum Hall states: Investigation of the anomalous line shape near ν=1
NASA Astrophysics Data System (ADS)
Dean, C. R.; Piot, B. A.; Pfeiffer, L. N.; West, K. W.; Gervais, G.
2008-03-01
A study of the resistively detected nuclear magnetic resonance (RDNMR) lineshape in the vicinity of ν=1 was performed on a high-mobility 2D electron gas formed in GaAs/AlGaAs. In higher Landau levels, application of an RF field at the nuclear magnetic resonance frequency coincides with an observed minimum in the longitudinal resistance, as predicted by the simple hyperfine interaction picture. Near ν=1 however, an anomalous dispersive lineshape is observed where a resistance peak follows the usual minimum. In an effort to understand the origin of this anomalous peak we have studied the resonance under various RF and sample conditions. Interestingly, we show that the lineshape can be completely inverted by simply applying a DC current. We interpret this as evidence that the minima and maxima in the lineshape originate from two distinct mechanisms.
Time-series investigation of anomalous thermocouple responses in a liquid-metal-cooled reactor
Gross, K.C.; Planchon, H.P.; Poloncsik, J.
1988-03-24
A study was undertaken using SAS software to investigate the origin of anomalous temperature measurements recorded by thermocouples (TCs) in an instrumented fuel assembly in a liquid-metal-cooled nuclear reactor. SAS macros that implement univariate and bivariate spectral decomposition techniques were employed to analyze data recorded during a series of experiments conducted at full reactor power. For each experiment, data from physical sensors in the tests assembly were digitized at a sampling rate of 2/s and recorded on magnetic tapes for subsequent interactive processing with CMS SAS. Results from spectral and cross-correlation analyses led to the identification of a flow rate-dependent electromotive force (EMF) phenomenon as the origin of the anomalous TC readings. Knowledge of the physical mechanism responsible for the discrepant TC signals enabled us to device and justify a simple correction factor to be applied to future readings.
Anomalous bond length behavior and a new solid phase of bromine under pressure
NASA Astrophysics Data System (ADS)
Wu, Min; Tse, John S.; Pan, Yuanming
2016-05-01
The behavior of diatomic molecular solids under pressure have attracted great interest and been extensively studied. Under ambient pressure, the structure of bromine is known to be a molecular phase (phase I). With increasing pressure, it transforms into an incommensurate phase (phase V) before eventually to a monoatomic phase (phase II). However, between phases I and V, the interatomic distance was found to first increase with pressure and then decreased abruptly. This anomalous bond length behavior is accompanied by the splitting of the Raman bands. These phenomena have not been resolved. Here we suggest a new solid phase that explains the Raman spectra. Furthermore, the anomalous bond length behavior is found to be the result of subtle second neighbor intermolecular interactions and is an intrinsic property of bromine in molecular phases.
Anomalous waves in gas-liquid mixtures near gas critical point in Gardner equation approximation
NASA Astrophysics Data System (ADS)
Gasenko, V. G.
2016-10-01
The waves in a bubbled incompressible liquid with Van der Waals gas in a bubbles being near critical points is considered in a frame of Gardner equation. It is shown that both coefficients on quadratic and cubic nonlinear terms in Gardner equation change the sign near gas critical point and it results the anomalous waves: negative and limited solitons, kinks, antikinks and breathers. The dynamics and interactions of these waves was studied numerically by high accuracy Fourier methods with periodically boundary conditions. In particular it is revealed that limited solitons always arise from initial distribution with a few identical soliton's pair and stand stable in their form after numerous interactions.
Anomalous Hysteresis in Perovskite Solar Cells.
Snaith, Henry J; Abate, Antonio; Ball, James M; Eperon, Giles E; Leijtens, Tomas; Noel, Nakita K; Stranks, Samuel D; Wang, Jacob Tse-Wei; Wojciechowski, Konrad; Zhang, Wei
2014-05-01
Perovskite solar cells have rapidly risen to the forefront of emerging photovoltaic technologies, exhibiting rapidly rising efficiencies. This is likely to continue to rise, but in the development of these solar cells there are unusual characteristics that have arisen, specifically an anomalous hysteresis in the current-voltage curves. We identify this phenomenon and show some examples of factors that make the hysteresis more or less extreme. We also demonstrate stabilized power output under working conditions and suggest that this is a useful parameter to present, alongside the current-voltage scan derived power conversion efficiency. We hypothesize three possible origins of the effect and discuss its implications on device efficiency and future research directions. Understanding and resolving the hysteresis is essential for further progress and is likely to lead to a further step improvement in performance.
Precise Quantization of Anomalous Hall Effect
NASA Astrophysics Data System (ADS)
Bestwick, Andrew
In the quantum anomalous Hall effect, electron transport in a magnetically-doped topological insulator takes place through chiral, dissipationless edge channels. In this talk, we discuss the behavior of a nearly ideal implementations of the effect in which the Hall resistance is within a part per 10,000 of its quantized value and the longitudinal resistivity can reach below 1 Ω per square. Nearly all Cr-doped topological insulator samples demonstrate extreme temperature dependence that is well-modeled by a small effective gap, allowing control over quantization with an unexpected magnetocaloric effect. We also discuss measurements of new device geometries and non-local resistances that identify the sources of dissipation that limit the effect. (Now at Rigetti Computing).
Observation of photonic anomalous Floquet topological insulators
NASA Astrophysics Data System (ADS)
Maczewsky, Lukas J.; Zeuner, Julia M.; Nolte, Stefan; Szameit, Alexander
2017-01-01
Topological insulators are a new class of materials that exhibit robust and scatter-free transport along their edges -- independently of the fine details of the system and of the edge -- due to topological protection. To classify the topological character of two-dimensional systems without additional symmetries, one commonly uses Chern numbers, as their sum computed from all bands below a specific bandgap is equal to the net number of chiral edge modes traversing this gap. However, this is strictly valid only in settings with static Hamiltonians. The Chern numbers do not give a full characterization of the topological properties of periodically driven systems. In our work, we implement a system where chiral edge modes exist although the Chern numbers of all bands are zero. We employ periodically driven photonic waveguide lattices and demonstrate topologically protected scatter-free edge transport in such anomalous Floquet topological insulators.
Observation of photonic anomalous Floquet topological insulators
Maczewsky, Lukas J.; Zeuner, Julia M.; Nolte, Stefan; Szameit, Alexander
2017-01-01
Topological insulators are a new class of materials that exhibit robust and scatter-free transport along their edges — independently of the fine details of the system and of the edge — due to topological protection. To classify the topological character of two-dimensional systems without additional symmetries, one commonly uses Chern numbers, as their sum computed from all bands below a specific bandgap is equal to the net number of chiral edge modes traversing this gap. However, this is strictly valid only in settings with static Hamiltonians. The Chern numbers do not give a full characterization of the topological properties of periodically driven systems. In our work, we implement a system where chiral edge modes exist although the Chern numbers of all bands are zero. We employ periodically driven photonic waveguide lattices and demonstrate topologically protected scatter-free edge transport in such anomalous Floquet topological insulators. PMID:28051080
Anomalous Diffusion of Single Particles in Cytoplasm
Regner, Benjamin M.; Vučinić, Dejan; Domnisoru, Cristina; Bartol, Thomas M.; Hetzer, Martin W.; Tartakovsky, Daniel M.; Sejnowski, Terrence J.
2013-01-01
The crowded intracellular environment poses a formidable challenge to experimental and theoretical analyses of intracellular transport mechanisms. Our measurements of single-particle trajectories in cytoplasm and their random-walk interpretations elucidate two of these mechanisms: molecular diffusion in crowded environments and cytoskeletal transport along microtubules. We employed acousto-optic deflector microscopy to map out the three-dimensional trajectories of microspheres migrating in the cytosolic fraction of a cellular extract. Classical Brownian motion (BM), continuous time random walk, and fractional BM were alternatively used to represent these trajectories. The comparison of the experimental and numerical data demonstrates that cytoskeletal transport along microtubules and diffusion in the cytosolic fraction exhibit anomalous (nonFickian) behavior and posses statistically distinct signatures. Among the three random-walk models used, continuous time random walk provides the best representation of diffusion, whereas microtubular transport is accurately modeled with fractional BM. PMID:23601312
Anomalous Flavor U(1)_X for Everything
Dreiner, Herbi K.; Murayama, Hitoshi; Thormeier, Marc
2003-12-01
We present an ambitious model of flavor, based on an anomalous U(1)_X gauge symmetry with one flavon, only two right-handed neutrinos and only two mass scales: M_{grav} and m_{3/2}. In particular, there are no new scales introduced for right-handed neutrino masses. The X-charges of the matter fields are such that R-parity is conserved exactly, higher-dimensional operators are sufficiently suppressed to guarantee a proton lifetime in agreement with experiment, and the phenomenology is viable for quarks, charged leptons, as well as neutrinos. In our model one of the three light neutrinos automatically is massless. The price we have to pay for this very successful model are highly fractional X-charges which can likely be improved with less restrictive phenomenological ansatze for mass matrices.
Communication: Probing anomalous diffusion in frequency space
Stachura, Sławomir; Kneller, Gerald R.
2015-11-21
Anomalous diffusion processes are usually detected by analyzing the time-dependent mean square displacement of the diffusing particles. The latter evolves asymptotically as W(t) ∼ 2D{sub α}t{sup α}, where D{sub α} is the fractional diffusion constant and 0 < α < 2. In this article we show that both D{sub α} and α can also be extracted from the low-frequency Fourier spectrum of the corresponding velocity autocorrelation function. This offers a simple method for the interpretation of quasielastic neutron scattering spectra from complex (bio)molecular systems, in which subdiffusive transport is frequently encountered. The approach is illustrated and validated by analyzing molecular dynamics simulations of molecular diffusion in a lipid POPC bilayer.
Anomalous Stress Response of Ultrahard WBn Compounds
NASA Astrophysics Data System (ADS)
Li, Quan; Zhou, Dan; Zheng, Weitao; Ma, Yanming; Chen, Changfeng
2015-10-01
Boron-rich tungsten borides are premier prototypes of a new class of ultrahard compounds. Here, we show by first-principles calculations that their stress-strain relations display surprisingly diverse and anomalous behavior under a variety of loading conditions. Most remarkable is the dramatically changing bonding configurations and deformation modes with rising boron concentration in WBn (n =2 , 3, 4), resulting in significantly different stress responses and unexpected indentation strength variations. This novel phenomenon stems from the peculiar structural arrangements in tungsten borides driven by boron's ability to form unusually versatile bonding states. Our results elucidate the intriguing deformation mechanisms that define a distinct type of ultrahard material. These new insights underscore the need to explore unconventional structure-property relations in a broad range of transition-metal light-element compounds.
Universal scaling of the anomalous Hall effect
NASA Astrophysics Data System (ADS)
Zhang, Xiaoqian; Wang, Wei; Wang, Kejie; Niu, Wei; Lai, Bolin; Maltby, Nick; Yang, Mao; Gao, Ming; Liu, Wenqing; He, Liang; Zhang, Rong; Xu, Yongbing
2017-04-01
We have undertaken a detailed study of the magneto-transport properties of ultra-thin Fe films epitaxially grown on GaAs (1 0 0). A metal–semiconductor transition has been observed with a critical thickness of 1.25 nm, which was thought to be related to the thermally activated tunneling between metallic clusters. By fitting {ρ\\text{AH}} versus ρ xx2 with the TYJ equation (Tian et al 2009 Phys. Rev. Lett. 103 087206), we found that the magnetization is negligible for the scaling of the anomalous Hall effect in ultra-thin Fe films. Furthermore, the intrinsic term, which is acquired by the linear fitting of {ρ\\text{AH}} versus ρ xx2 , shows an obvious decrease when the film thickness drops below 1.25 nm, which was thought to be related to the fading of the Berry curvature in the ultra-thin film limit.
Chiral magnetic plasmons in anomalous relativistic matter
NASA Astrophysics Data System (ADS)
Gorbar, E. V.; Miransky, V. A.; Shovkovy, I. A.; Sukhachov, P. O.
2017-03-01
The chiral plasmon modes of relativistic matter in background magnetic and strain-induced pseudomagnetic fields are studied in detail using the consistent chiral kinetic theory. The results reveal a number of anomalous features of these chiral magnetic and pseudomagnetic plasmons that could be used to identify them in experiment. In a system with nonzero electric (chiral) chemical potential, the background magnetic (pseudomagnetic) fields not only modify the values of the plasmon frequencies in the long-wavelength limit, but also affect the qualitative dependence on the wave vector. Similar modifications can be also induced by the chiral shift parameter in Weyl materials. Interestingly, even in the absence of the chiral shift and external fields, the chiral chemical potential alone leads to a splitting of plasmon energies at linear order in the wave vector.
Anomalous normal mode oscillations in semiconductor microcavities
Wang, H.; Hou, H.Q.; Hammons, B.E.
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.
Anomalous stress response of ultrahard WBn compounds
Li, Quan; Zhou, Dan; Zheng, Weitao; ...
2015-10-29
Boron-rich tungsten borides are premier prototypes of a new class of ultrahard compounds. Here, we show by first-principles calculations that their stress-strain relations display surprisingly diverse and anomalous behavior under a variety of loading conditions. Most remarkable is the dramatically changing bonding configurations and deformation modes with rising boron concentration in WBn (n=2, 3, 4), resulting in significantly different stress responses and unexpected indentation strength variations. This novel phenomenon stems from the peculiar structural arrangements in tungsten borides driven by boron’s ability to form unusually versatile bonding states. Our results elucidate the intriguing deformation mechanisms that define a distinct typemore » of ultrahard material. Here, these new insights underscore the need to explore unconventional structure-property relations in a broad range of transition-metal light-element compounds.« less
Anomalous krypton in the Allende meteorite
NASA Technical Reports Server (NTRS)
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.
NASA Astrophysics Data System (ADS)
Chen, Rui; Li, Xiangdong
2002-03-01
In the last few years it has been recognized that a group of X-ray pulsars have peculiar properties which set them apart from the majority of accreting pulars in X-ray binaries. They are called the Anomalous X-ray Pulsars (AXP). These objects are characterized by very soft X-ray spectra with low and steady X-ray fluxes, narrow-distributed spin periods, steady spin-down, no optical/infrared counterparts. Some of them may associate with supernova remnants. The nature of AXP remains mysterious. It has been suggested that AXP are accreting neutron stars, or solitary "magnetars", neutron stars with super strong magnetic fields (≍1010-1011T). In this paper we review the recent progress in the studies of AXP, and discuss the possible implications from comparison of AXP with other neutron stars, such as radio pulsars, radio quiet X-ray pulsar candidates and soft γ-ray repeaters.
Cyclotron maser using the anomalous Doppler effect
NASA Astrophysics Data System (ADS)
Didenko, A. N.; Borisov, A. R.; Fomenko, G. P.; Shlapakovskii, A. S.; Shtein, Iu. G.
1983-11-01
The operation of an anomalous-Doppler-effect cyclotron-resonance maser using a waveguide partially filled with dielectric as the slow-wave system is reported. The device investigated is similar to that of Didenko et al. (1983) and comprises a 300-mm-long 50-mm-o.d. 30-mm-i.d. waveguide with fabric-laminate dielectric, located 150 mm from the cathode in a 500-mm-long region of uniform 0-20-kG magnetic field, and a coaxial magnetic-insulation gun producing a 13-mm-i.d. 25-mm-o.d. hollow electron beam. Radiation at 12 + or - 1 mm wavelength and optimum power 20 MW is observed using hot-carrier detectors, with a clear peak in the power-versus-magnetic-field curve at about 6.4 kG.
Revisit to diffraction anomalous fine structure
Kawaguchi, T.; Fukuda, K.; Tokuda, K.; Shimada, K.; Ichitsubo, T.; Oishi, M.; Mizuki, J.; Matsubara, E.
2014-01-01
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 Fe3O4 powder, to demonstrate the validity of the measurement and the analysis of the present DAFS method. PMID:25343791
Anomalous electrical conductivity of nanoscale colloidal suspensions.
Chakraborty, Suman; Padhy, Sourav
2008-10-28
The electrical conductivity of colloidal suspensions containing nanoscale conducting particles is nontrivially related to the particle volume fraction and the electrical double layer thickness. Classical electrochemical models, however, tend to grossly overpredict the pertinent effective electrical conductivity values, as compared to those obtained under experimental conditions. We attempt to address this discrepancy by appealing to the complex interconnection between the aggregation kinetics of the nanoscale particles and the electrodynamics within the double layer. In particular, we model the consequent alterations in the effective electrophoretic mobility values of the suspension by addressing the fundamentals of agglomeration-deagglomeration mechanisms through the pertinent variations in the effective particulate dimensions, solid fractions, as well as the equivalent suspension viscosity. The consequent alterations in the electrical conductivity values provide a substantially improved prediction of the corresponding experimental findings and explain the apparent anomalous behavior predicted by the classical theoretical postulates.
Anomalous magnetoresistance in magnetized topological insulator cylinders
Siu, Zhuo Bin; Jalil, Mansoor B. A.
2015-05-07
The close coupling between the spin and momentum degrees of freedom in topological insulators (TIs) presents the opportunity for the control of one to manipulate the other. The momentum can, for example, be confined on a curved surface and the spin influenced by applying a magnetic field. In this work, we study the surface states of a cylindrical TI magnetized in the x direction perpendicular to the cylindrical axis lying along the z direction. We show that a large magnetization leads to an upwards bending of the energy bands at small |k{sub z}|. The bending leads to an anomalous magnetoresistance where the transmission between two cylinders magnetized in opposite directions is higher than when the cylinders are magnetized at intermediate angles with respect to each other.
Heterogeneous anomalous diffusion in view of superstatistics
NASA Astrophysics Data System (ADS)
Itto, Yuichi
2014-08-01
It is experimentally known that virus exhibits stochastic motion in cytoplasm of a living cell in the free form as well as the form being contained in the endosome and the exponent of anomalous diffusion of the virus fluctuates depending on localized areas of the cytoplasm. Here, a theory is developed for establishing a generalized fractional kinetics for the infection pathway of the virus in the cytoplasm in view of superstatistics, which offers a general framework for describing nonequilibrium complex systems with two largely separated time scales. In the present theory, the existence of a large time-scale separation in the infection pathway is explicitly taken into account. A comment is also made on scaling nature of the motion of the virus that is suggested by the theory.
Anomalous cases of astronaut helmet detection
NASA Astrophysics Data System (ADS)
Dolph, Chester; Moore, Andrew J.; Schubert, Matthew; Woodell, Glenn
2015-05-01
An astronaut's helmet is an invariant, rigid image element that is well suited for identification and tracking using current machine vision technology. Future space exploration will benefit from the development of astronaut detection software for search and rescue missions based on EVA helmet identification. However, helmets are solid white, except for metal brackets to attach accessories such as supplementary lights. We compared the performance of a widely used machine vision pipeline on a standard-issue NASA helmet with and without affixed experimental feature-rich patterns. Performance on the patterned helmet was far more robust. We found that four different feature-rich patterns are sufficient to identify a helmet and determine orientation as it is rotated about the yaw, pitch, and roll axes. During helmet rotation the field of view changes to frames containing parts of two or more feature-rich patterns. We took reference images in these locations to fill in detection gaps. These multiple feature-rich patterns references added substantial benefit to detection, however, they generated the majority of the anomalous cases. In these few instances, our algorithm keys in on one feature-rich pattern of the multiple feature-rich pattern reference and makes an incorrect prediction of the location of the other feature-rich patterns. We describe and make recommendations on ways to mitigate anomalous cases in which detection of one or more feature-rich patterns fails. While the number of cases is only a small percentage of the tested helmet orientations, they illustrate important design considerations for future spacesuits. In addition to our four successful feature-rich patterns, we present unsuccessful patterns and discuss the cause of their poor performance from a machine vision perspective. Future helmets designed with these considerations will enable automated astronaut detection and thereby enhance mission operations and extraterrestrial search and rescue.
Powder diffraction studies using anomalous dispersion
Cox, D.E. ); Wilkinson, A.P. . Dept. of Materials)
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 [Tc] superconductors, ternary alloys, FeCo[sub 2](PO[sub 4])[sub 3], FeNi[sub 2]BO[sub 5]), oxidation-state contrast (e.g. YBa[sub 2]Cu[sub 3]O[sub 6+x], Eu[sub 3]O[sub 4], GaCl[sub 2], Fe[sub 2]PO[sub 5]), and the effect of coordination geometry (e.g. Y[sub 3]Ga[sub 5]O[sub l2]).
Powder diffraction studies using anomalous dispersion
Cox, D.E.; Wilkinson, A.P.
1993-05-01
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 {Tc} superconductors, ternary alloys, FeCo{sub 2}(PO{sub 4}){sub 3}, FeNi{sub 2}BO{sub 5}), oxidation-state contrast (e.g. YBa{sub 2}Cu{sub 3}O{sub 6+x}, Eu{sub 3}O{sub 4}, GaCl{sub 2}, Fe{sub 2}PO{sub 5}), and the effect of coordination geometry (e.g. Y{sub 3}Ga{sub 5}O{sub l2}).
Anomalous Cases of Astronaut Helmet Detection
NASA Technical Reports Server (NTRS)
Dolph, Chester; Moore, Andrew J.; Schubert, Matthew; Woodell, Glenn
2015-01-01
An astronaut's helmet is an invariant, rigid image element that is well suited for identification and tracking using current machine vision technology. Future space exploration will benefit from the development of astronaut detection software for search and rescue missions based on EVA helmet identification. However, helmets are solid white, except for metal brackets to attach accessories such as supplementary lights. We compared the performance of a widely used machine vision pipeline on a standard-issue NASA helmet with and without affixed experimental feature-rich patterns. Performance on the patterned helmet was far more robust. We found that four different feature-rich patterns are sufficient to identify a helmet and determine orientation as it is rotated about the yaw, pitch, and roll axes. During helmet rotation the field of view changes to frames containing parts of two or more feature-rich patterns. We took reference images in these locations to fill in detection gaps. These multiple feature-rich patterns references added substantial benefit to detection, however, they generated the majority of the anomalous cases. In these few instances, our algorithm keys in on one feature-rich pattern of the multiple feature-rich pattern reference and makes an incorrect prediction of the location of the other feature-rich patterns. We describe and make recommendations on ways to mitigate anomalous cases in which detection of one or more feature-rich patterns fails. While the number of cases is only a small percentage of the tested helmet orientations, they illustrate important design considerations for future spacesuits. In addition to our four successful feature-rich patterns, we present unsuccessful patterns and discuss the cause of their poor performance from a machine vision perspective. Future helmets designed with these considerations will enable automated astronaut detection and thereby enhance mission operations and extraterrestrial search and rescue.
On the quantum mechanics of consciousness, with application to anomalous phenomena
NASA Astrophysics Data System (ADS)
Jahn, Robert G.; Dunne, Brenda J.
1986-08-01
Theoretical explication of a growing body of empirical data on consciousness-related anomalous phenomena is unlikely to be achieved in terms of known physical processes. Rather, it will first be necessary to formulate the basic role of consciousness in the definition of reality before such anomalous experience can adequately be represented. This paper takes the position that reality is constituted only in the interaction of consciousness with its environment, and therefore that any scheme of conceptual organization developed to represent that reality must reflect the processes of consciousness as well as those of its environment. In this spirit, the concepts and formalisms of elementary quantum mechanics, as originally proposed to explain anomalous atomic-scale physical phenomena, are appropriated via metaphor to represent the general characteristics of consciousness interacting with any environment. More specifically, if consciousness is represented by a quantum mechanical wave function, and its environment by an appropriate potential profile, Schrödinger wave mechanics defines eigenfunctions and eigenvalues that can be associated with the cognitive and emotional experiences of that consciousness in that environment. To articulate this metaphor it is necessary to associate certain aspects of the formalism, such as the coordinate system, the quantum numbers, and even the metric itself, with various impressionistic descriptors of consciousness, such as its intensity, perspective, approach/avoidance attitude, balance between cognitive and emotional activity, and receptive/assertive disposition. With these established, a number of the generic features of quantum mechanics, such as the wave/particle duality, and the uncertainty, indistinguishability, and exclusion principles, display metaphoric relevance to familiar individual and collective experiences. Similarly, such traditional quantum theoretic exercises as the central force field and atomic structure, covalent
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.
Anomalous diffusion process applied to magnetic resonance image enhancement.
Senra Filho, A C da S; Salmon, C E Garrido; Murta Junior, L O
2015-03-21
Diffusion process is widely applied to digital image enhancement both directly introducing diffusion equation as in anisotropic diffusion (AD) filter, and indirectly by convolution as in Gaussian filter. Anomalous diffusion process (ADP), given by a nonlinear relationship in diffusion equation and characterized by an anomalous parameters q, is supposed to be consistent with inhomogeneous media. Although classic diffusion process is widely studied and effective in various image settings, the effectiveness of ADP as an image enhancement is still unknown. In this paper we proposed the anomalous diffusion filters in both isotropic (IAD) and anisotropic (AAD) forms for magnetic resonance imaging (MRI) enhancement. Filters based on discrete implementation of anomalous diffusion were applied to noisy MRI T2w images (brain, chest and abdominal) in order to quantify SNR gains estimating the performance for the proposed anomalous filter when realistic noise is added to those images. Results show that for images containing complex structures, e.g. brain structures, anomalous diffusion presents the highest enhancements when compared to classical diffusion approach. Furthermore, ADP presented a more effective enhancement for images containing Rayleigh and Gaussian noise. Anomalous filters showed an ability to preserve anatomic edges and a SNR improvement of 26% for brain images, compared to classical filter. In addition, AAD and IAD filters showed optimum results for noise distributions that appear on extreme situations on MRI, i.e. in low SNR images with approximate Rayleigh noise distribution, and for high SNR images with Gaussian or non central χ noise distributions. AAD and IAD filter showed the best results for the parametric range 1.2 < q < 1.6, suggesting that the anomalous diffusion regime is more suitable for MRI. This study indicates the proposed anomalous filters as promising approaches in qualitative and quantitative MRI enhancement.
Concepts of ferrovalley material and anomalous valley Hall effect.
Tong, Wen-Yi; Gong, Shi-Jing; Wan, Xiangang; Duan, Chun-Gang
2016-12-16
Valleytronics rooted in the valley degree of freedom is of both theoretical and technological importance as it offers additional opportunities for information storage, as well as electronic, magnetic and optical switches. In analogy to ferroelectric materials with spontaneous charge polarization, or ferromagnetic materials with spontaneous spin polarization, here we introduce a new member of ferroic family, that is, a ferrovalley material with spontaneous valley polarization. Combining a two-band k·p model with first-principles calculations, we show that 2H-VSe2 monolayer, where the spin-orbit coupling coexists with the intrinsic exchange interaction of transition-metal d electrons, is such a room-temperature ferrovalley material. We further predict that such system could demonstrate many distinctive properties, for example, chirality-dependent optical band gap and, more interestingly, anomalous valley Hall effect. On account of the latter, functional devices based on ferrovalley materials, such as valley-based nonvolatile random access memory and valley filter, are contemplated for valleytronic applications.
Concepts of ferrovalley material and anomalous valley Hall effect
Tong, Wen-Yi; Gong, Shi-Jing; Wan, Xiangang; Duan, Chun-Gang
2016-01-01
Valleytronics rooted in the valley degree of freedom is of both theoretical and technological importance as it offers additional opportunities for information storage, as well as electronic, magnetic and optical switches. In analogy to ferroelectric materials with spontaneous charge polarization, or ferromagnetic materials with spontaneous spin polarization, here we introduce a new member of ferroic family, that is, a ferrovalley material with spontaneous valley polarization. Combining a two-band k·p model with first-principles calculations, we show that 2H-VSe2 monolayer, where the spin–orbit coupling coexists with the intrinsic exchange interaction of transition-metal d electrons, is such a room-temperature ferrovalley material. We further predict that such system could demonstrate many distinctive properties, for example, chirality-dependent optical band gap and, more interestingly, anomalous valley Hall effect. On account of the latter, functional devices based on ferrovalley materials, such as valley-based nonvolatile random access memory and valley filter, are contemplated for valleytronic applications. PMID:27982088
Room Temperature Ferromagnetic Polymer and the Correlated Anomalous Magnetoresistance Phenomenon
NASA Astrophysics Data System (ADS)
Huang, Jinsong; Yang, Bin; Shield, Jeffrey
2011-03-01
Organic magnetoresistance (OMAR) has been observed in organic semiconductor devices where resistance can change in a relatively small external magnetic field at room temperature. Since a weak magnetic field is involved, the hyperfine interaction (HFI) is employed to explain OMAR in the reported literatures. None of these issues consider the magnetic properties of the organic semiconductors themselves. However, the we recently discovered that polymer semiconductors, such as poly(3-hexylthiophene) P3HT, can have room temperature (RT) ferromagnetic properties in their crystalline phase and when mixed with phenyl-C61-butyric acid methyl ester (PCBM). Here, we will report the possible correlation between the ferromagnetic property of the P3HT:PCBM and anomalous OMAR phenomenon including the anisotropic and hysteretic OMAR behavior. The magnetic property of the polymer including the anisotropic and photo induced change of magnetism will be also discussed to explore the possible mechanism of the room temperature ferromagnetism.~ This work is partially supported by the NSF MRSEC program at University.
Quantum anomalous Hall effect in stanene on a nonmagnetic substrate
NASA Astrophysics Data System (ADS)
Zhang, Huisheng; Zhou, Tong; Zhang, Jiayong; Zhao, Bao; Yao, Yugui; Yang, Zhongqin
2016-12-01
Since the quantum anomalous Hall (QAH) effect was realized in magnetic topological insulators, research on the effect has become a hot topic. The very harsh realizing requirements of the effect in experiments, however, hinder its practical applications. Based on ab initio methods, we find that nonmagnetic Pb I2 films are ideal substrates for the two-dimensional honeycomb stanene. The QAH effect with a pretty large band gap (up to 90 meV) can be achieved in the functionalized stanene /Pb I2 heterostructure. Despite van der Waals interactions in the heterostructure, band inversions are found to be happening between Sn (s and px ,y ) and Pb (px ,y) orbitals, playing a key role in determining the nontrivial topology and the large band gap of the system. Having no magnetic atoms is imperative to triggering the QAH effect. A very stable rudimentary device having QAH effects is proposed based on the Sn /Pb I2 heterostructure. Our results demonstrate that QAH effects can be easily realized in the Sn /Pb I2 heterostructures in experiments.
Concepts of ferrovalley material and anomalous valley Hall effect
NASA Astrophysics Data System (ADS)
Tong, Wen-Yi; Gong, Shi-Jing; Wan, Xiangang; Duan, Chun-Gang
2016-12-01
Valleytronics rooted in the valley degree of freedom is of both theoretical and technological importance as it offers additional opportunities for information storage, as well as electronic, magnetic and optical switches. In analogy to ferroelectric materials with spontaneous charge polarization, or ferromagnetic materials with spontaneous spin polarization, here we introduce a new member of ferroic family, that is, a ferrovalley material with spontaneous valley polarization. Combining a two-band k.p model with first-principles calculations, we show that 2H-VSe2 monolayer, where the spin-orbit coupling coexists with the intrinsic exchange interaction of transition-metal d electrons, is such a room-temperature ferrovalley material. We further predict that such system could demonstrate many distinctive properties, for example, chirality-dependent optical band gap and, more interestingly, anomalous valley Hall effect. On account of the latter, functional devices based on ferrovalley materials, such as valley-based nonvolatile random access memory and valley filter, are contemplated for valleytronic applications.
Anomalously small BBR shift in Tl^+ frequency standard
NASA Astrophysics Data System (ADS)
Zuhrianda, Z.; Safronova, Marianna; Kozlov, Mikhail
2012-06-01
The operation of atomic clocks is generally carried out at room temperature, whereas the definition of the second refers to the clock transition in an atom at absolute zero. This implies that the clock transition frequency should be corrected in practice for the effect of finite temperature of which the leading contributor is the blackbody radiation (BBR) shift. In the present work, we have used configuration interaction + coupled-cluster method to evaluate polarizabilities of the 6s^2 ^1S0 and 6s6p ^3P0 states of Tl^+; α0(^1S0)=19.5 a.u. and α0(^3P0)=21.4 a.u.. We find dynamic correction to the BBR shift to be negligible. The resulting BBR shift at 300 K is δνBBR=-0.0166(17) Hz. This result demonstrates that near cancelation of the ^1S0 and ^3P0 state polarizabilities in monovalent B^+, Al^+, In^+ ions of group 13 [Safronova et al., PRL 107, 143006 (2011)] continues for much heavier Tl^+, leading to anomalously small BBR shift for this system. The corresponding relative BBR shift at 300 K is |δνBBR/ν0|=1.1(1)x10-17. This calculation demonstrates that the BBR contribution to the fractional frequency uncertainty of the Tl^+ frequency standard at 300 K is 1x10-18.
Anomalous Reflection of Gold: A Novel Platform for Biochips.
Syahir, Amir; Tomizaki, Kin-ya; Kajikawa, Kotaro; Mihara, Hisakazu
2016-01-01
The importance of protein detection system for protein functions analyses in recent post-genomic era is rising with the emergence of label-free protein detection methods. We are focusing on a simple and practical label-free optical-detection method called anomalous reflection (AR) of gold. When a molecular layer forms on the gold surface, significant reduction in reflectivity can be observed at wavelengths of 400-500 nm. This allows the detection of molecular interactions by monitoring changes in reflectivity. In this chapter, we describe the AR method with three different application platforms: (1) gold, (2) gold containing alloy/composite (AuAg2O), and (3) metal-insulator-metal (MIM) thin layers. The AuAg2O composite and MIM are implemented as important concepts for signal enhancement process for the AR technique. Moreover, the observed molecular adsorption and activity is aided by a three-dimensional surface geometry, performed using poly(amidoamine) or PAMAM dendrimer modification. The described system is suitable to be used as a platform for high-throughput detection system in a chip format.
Anomalous astronomical time-latitude residuals: a potential earthquake precursor
NASA Astrophysics Data System (ADS)
Hu, Hui; Su, You-Jin; Gao, Yi-Fei; Wang, Rui
2016-09-01
The geophysical mechanism behind astronomical time-latitude residuals (ATLR) are discussed. The photoelectric astrolabe at Yunnan Observatory (YO) observed apparent synchronous anomalous ATLR before the Wenchuan M8.0 earthquake (EQ) in May 12, 2008 and the Lushan M7.0 EQ n April 20, 2013. We compared the ATLR from the YO photoelectric astrolabe and EQ data since 1976. Anomalous ATLR was observed before several strong EQs in the Yunnan Province. We believe the photoelectric astrolabe can be used to predict strong EQs and the anomalous ATLR are a potential EQ precursor.
No-Drag Frame for Anomalous Chiral Fluid
Stephanov, Mikhail A.; Yee, Ho-Ung
2016-03-24
For an anomalous fluid carrying dissipationless chiral magnetic and/or vortical currents we show that there is a frame in which a stationary obstacle experiences no drag, but energy and charge currents do not vanish, resembling superfluidity. Unlike ordinary superfluid flow, the anomalous chiral currents can transport entropy in this frame. Moreover, we show that the second law of thermodynamics completely determines the amounts of these anomalous nondissipative currents in the “no-drag frame” as polynomials in temperature and chemical potential with known anomaly coefficients. These general results are illustrated and confirmed by a calculation in the chiral kinetic theory and in the quark-gluon plasma at high temperature.
Broken Scale Invariance and Anomalous Dimensions
DOE R&D Accomplishments Database
Wilson, K. G.
1970-05-01
Mack and Kastrup have proposed that broken scale invariance is a symmetry of strong interactions. There is evidence from the Thirring model and perturbation theory that the dimensions of fields defined by scale transformations will be changed by the interaction from their canonical values. We review these ideas and their consequences for strong interactions.
Coherent control of double deflected anomalous modes in ultrathin trapezoid-shaped slit metasurface
Zhu, Z.; Liu, H.; Wang, D.; Li, Y. X.; Guan, C. Y.; Zhang, H.; Shi, J. H.
2016-01-01
Coherent light-matter interaction in ultrathin metamaterials has been demonstrated to dynamically modulate intensity, polarization and propagation direction of light. The gradient metasurface with a transverse phase variation usually exhibits an anomalous refracted beam of light dictated by so-called generalized Snell’s law. However, less attention has been paid to coherent control of the metasurface with multiple anomalous refracted beams. Here we propose an ultrathin gradient metasurface with single trapezoid-shaped slot antenna as its building block that allows one normal and two deflected transmitted beams. It is numerically demonstrated that such metasurface with multiple scattering modes can be coherently controlled to modulate output intensities by changing the relative phase difference between two counterpropagating coherent beams. Each mode can be coherently switched on/off and two deflected anomalous beams can be synchronously dictated by the phase difference. The coherent control effect in the trapezoid-shaped slit metasurface will offer a promising opportunity for multichannel signals modulation, multichannel sensing and wave front shaping. PMID:27874053
A dynamic model for anomalous figures: the shape of line-induced brightness modifications.
Pinna, B; Sambin, M
1991-01-01
It is recognized that a fundamental role in the perception of anomalous figures is played by the intensity and shape of brightness modifications induced by line ends. The aim of this work was to study the structure of these modifications experimentally, by using variously arranged dots as probes. It was thus assumed that dots can measure activations generated inside abrupt line ends. The results show distribution of activation which differs according to dot distance and angle with respect to the continuation of the line near its end. These data do not agree with the predictions of information processing models in the literature on anomalous figures, which are based on perceptually postulated figures accounting for unlikely gaps. However, they do agree with the dynamic model proposed here, which is based on the idea that certain figure characteristics, eg the differential brightness of anomalous figures, depend on activation distribution which in turn depends on the organization of the forces in play. This idea is rooted in Gestalt theory. Another model supported by our experimental data is Grossberg's neural dynamic approach. In this case too, the basic idea is that of activation distribution which depends on the interaction of complex neural networks functioning according to special algorithms.
TargetVue: Visual Analysis of Anomalous User Behaviors in Online Communication Systems.
Cao, Nan; Shi, Conglei; Lin, Sabrina; Lu, Jie; Lin, Yu-Ru; Lin, Ching-Yung
2016-01-01
Users with anomalous behaviors in online communication systems (e.g. email and social medial platforms) are potential threats to society. Automated anomaly detection based on advanced machine learning techniques has been developed to combat this issue; challenges remain, though, due to the difficulty of obtaining proper ground truth for model training and evaluation. Therefore, substantial human judgment on the automated analysis results is often required to better adjust the performance of anomaly detection. Unfortunately, techniques that allow users to understand the analysis results more efficiently, to make a confident judgment about anomalies, and to explore data in their context, are still lacking. In this paper, we propose a novel visual analysis system, TargetVue, which detects anomalous users via an unsupervised learning model and visualizes the behaviors of suspicious users in behavior-rich context through novel visualization designs and multiple coordinated contextual views. Particularly, TargetVue incorporates three new ego-centric glyphs to visually summarize a user's behaviors which effectively present the user's communication activities, features, and social interactions. An efficient layout method is proposed to place these glyphs on a triangle grid, which captures similarities among users and facilitates comparisons of behaviors of different users. We demonstrate the power of TargetVue through its application in a social bot detection challenge using Twitter data, a case study based on email records, and an interview with expert users. Our evaluation shows that TargetVue is beneficial to the detection of users with anomalous communication behaviors.
Four-fermion production at γ γ colliders: 1. Lowest-order predictions and anomalous couplings
NASA Astrophysics Data System (ADS)
Bredenstein, A.; Dittmaier, S.; Roth, M.
2004-08-01
We have constructed a Monte Carlo generator (the corresponding FORTRAN code can be obtained from the authors upon request) for lowest-order predictions for the processes γγto 4f and γγto 4fγ in the standard model and extensions thereof by an effective γγ H coupling as well as anomalous triple and quartic gauge-boson couplings. Polarization is fully supported, and a realistic photon beam spectrum can be taken into account. For the processes γγto 4f all helicity amplitudes are explicitly given in a compact form. The presented numerical results contain, in particular, a survey of cross sections for representative final states and their comparison to results obtained with the program package Whizard/Madgraph. The impact of a realistic beam spectrum on cross sections and distributions is illustrated. Moreover, the size of various contributions to cross sections, such as from weak charged- or neutral-current, or from strong interactions, is analyzed. Particular attention is paid to W-pair production channels γγto W Wto 4f(γ) where we investigate the impact of background diagrams, possible definitions of the W-pair signal, and the issue of gauge-invariance violation caused by finite gauge-boson widths. Finally, the effects of triple and quartic anomalous gauge-boson couplings on cross sections as well as the possibility to constrain these anomalous couplings at future γγ colliders are discussed.
Coherent control of double deflected anomalous modes in ultrathin trapezoid-shaped slit metasurface
NASA Astrophysics Data System (ADS)
Zhu, Z.; Liu, H.; Wang, D.; Li, Y. X.; Guan, C. Y.; Zhang, H.; Shi, J. H.
2016-11-01
Coherent light-matter interaction in ultrathin metamaterials has been demonstrated to dynamically modulate intensity, polarization and propagation direction of light. The gradient metasurface with a transverse phase variation usually exhibits an anomalous refracted beam of light dictated by so-called generalized Snell’s law. However, less attention has been paid to coherent control of the metasurface with multiple anomalous refracted beams. Here we propose an ultrathin gradient metasurface with single trapezoid-shaped slot antenna as its building block that allows one normal and two deflected transmitted beams. It is numerically demonstrated that such metasurface with multiple scattering modes can be coherently controlled to modulate output intensities by changing the relative phase difference between two counterpropagating coherent beams. Each mode can be coherently switched on/off and two deflected anomalous beams can be synchronously dictated by the phase difference. The coherent control effect in the trapezoid-shaped slit metasurface will offer a promising opportunity for multichannel signals modulation, multichannel sensing and wave front shaping.
NASA Astrophysics Data System (ADS)
Foot, R.; Yoon, T. L.
2002-07-01
There are a number of very puzzling meteoritic events including (a) The Tunguska event. It is the only known example of a low altitude atmospheric explosion. It is also the largest recorded event. Remarkably no fragments or significant chemical traces have ever been recovered. (b) Anomalous low altitude fireballs which (in some cases) have been observed to hit the ground. The absence of fragments is particularly striking in these cases, but this is not the only reason they are anomalous. The other main puzzling feature is the lack of a consistent trajectory: low altitude fireballs, if caused by an ordinary cosmic body penetrating the Earth's atmosphere, should have been extremely luminous at high altitudes. But in these anomalous cases this is (remarkably) not observed to occur! On the other hand, there is strong evidence that most of our galaxy is made from exotic dark material -- `dark matter'. Mirror matter is one well motivated dark matter candidate, since it is dark and stable and it is required to exist if particle interactions are mirror symmetric. If mirror matter is the dark matter, then some amount must exist in our solar system. Although there is not much room for a large amount of mirror matter in the inner solar system, numerous small asteroid sized mirror matter objects are a fascinating possibility because they can potentially collide with the Earth. We demonstrate that the mirror matter theory allows for a simple explanation for the puzzling meteoritic events [both (a) and (b)] if they are due to mirror matter space-bodies. A direct consequence of this explanation is that mirror matter fragments should exist in (or on) the ground at various impact sites. The properties of this potentially recoverable material depend importantly on the sign of the photon-mirror photon kinetic mixing parameter, \\varepsilon . We argue that the broad characteristics of the anomalous events suggests that \\varepsilon is probably negative. Strategies for detecting mirror
Quantum anomalous Hall effect in real materials
NASA Astrophysics Data System (ADS)
Zhang, Jiayong; Zhao, Bao; Zhou, Tong; Yang, Zhongqin
2016-11-01
Under a strong magnetic field, the quantum Hall (QH) effect can be observed in two-dimensional electronic gas systems. If the quantized Hall conductivity is acquired in a system without the need of an external magnetic field, then it will give rise to a new quantum state, the quantum anomalous Hall (QAH) state. The QAH state is a novel quantum state that is insulating in the bulk but exhibits unique conducting edge states topologically protected from backscattering and holds great potential for applications in low-power-consumption electronics. The realization of the QAH effect in real materials is of great significance. In this paper, we systematically review the theoretical proposals that have been brought forward to realize the QAH effect in various real material systems or structures, including magnetically doped topological insulators, graphene-based systems, silicene-based systems, two-dimensional organometallic frameworks, quantum wells, and functionalized Sb(111) monolayers, etc. Our paper can help our readers to quickly grasp the recent developments in this field. Project supported by the National Basic Research Program of China (Grant No. 2011CB921803), the National Natural Science Foundation of China (Grant No. 11574051), the Natural Science Foundation of Shanghai, China (Grant No. 14ZR1403400), and Fudan High-end Computing Center, China.
Anomalous Magnetoresistance Phenomena in Organic Semiconductors
NASA Astrophysics Data System (ADS)
Bergeson, Jeremy D.; Lincoln, Derek M.; Shima Edelstein, Ruth; Prigodin, Vladimir N.; Epstein, Arthur J.
2006-03-01
We report magnetoresistance (MR) phenomena with temperature and bias dependence in organic semiconductor thin films with either nonmagnetic or magnetic contacts through high field reaching 9T. For nonmagnetic organic thin films such as Alq3 we find a low field MR up to 15%. A similar magnetic field effect has been reported earlier^1 but, as noted, the mechanism remains unclear. We propose a model of the anomalous MR where charge transport is space-charge limited. The current is determined by the e-h recombination rate. The recombination rate is field dependent, analogous to the chemical yield for radical pairs^2. Using an organic- based magnetic semiconductor^3, V[TCNE]x, and Co as magnetic contacts, with a nonmagnetic organic semiconductor (α-6T) leads to an order-of-magnitude broader zero-centered MR peak superimposed on a spin-valve effect. Possible origins of this broader MR will be discussed. 1. Francis, et al., New J. Phys. 6 185 (2004); Frankevich, et al., Phys. Rev. B 53 4498 (1996) 2. Steiner and Ulrich, Chem. Rev. 89 51 (1989) 3. Pokhodnya, et al., Adv. Mater. 12 410 (2000); Prigodin, et al., Adv. Mater. 14 1230 (2002); Shima Edelstein, et al., Mater. Res. Soc. Symp. Proc. 871E I7.3 (2005)
Anomalous Anticipatory Responses in Networked Random Data
Nelson, Roger D.; Bancel, Peter A.
2006-10-16
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.
EAWE: Examination of Anomalous World Experience.
Sass, Louis; Pienkos, Elizabeth; Skodlar, Borut; Stanghellini, Giovanni; Fuchs, Thomas; Parnas, Josef; Jones, Nev
2017-01-01
The "EAWE: Examination of Anomalous World Experience" is a detailed semi-structured interview format whose aim is to elicit description and discussion of a person's experience of various aspects of their lived world. The instrument is grounded in the tradition of phenomenological psychopathology and aims to explore, in a qualitatively rich manner, six key dimensions of subjectivity - namely, a person's experience of: (1) Space and objects, (2) Time and events, (3) Other persons, (4) Language (whether spoken or written), (5) Atmosphere (overall sense of reality, familiarity, vitality, meaning, or relevance), and (6) Existential orientation (values, attitudes, and worldviews). The EAWE is based on and primarily directed toward experiences thought to be common in, and sometimes distinctive of, schizophrenia spectrum conditions. It can, however, also be used to investigate anomalies of world experience in other populations. After a theoretical and methodological introduction, the EAWE lists 75 specific items, often with subtypes, in its six domains, together with illustrative quotations from patients. The EAWE appears in a special issue of Psychopathology that also contains an orienting preface (where the difficulty as well as necessity of studying subjective life is acknowledged) and a brief reliability report. Also included are six ancillary or background articles, which survey phenomenologically oriented theory, research, and clinical lore relevant to the six experiential domains.
Hadron collider limits on anomalous WWγ couplings
NASA Astrophysics Data System (ADS)
Barger, Kevin R.; Reno, M. H.
1995-01-01
A next-to-leading log calculation of the reactions pp and pp¯-->W+/-γX is presented including a triboson gauge coupling from non-standard-model contributions. The additional term arises by considering the standard model as a low energy effective theory. Two approaches are made for comparison. The first approach considers the triboson WWγ coupling as being uniquely fixed by tree level unitarity at high energies to its standard model form and, consequently, suppresses the non-standard-model contributions with form factors. The second approach is to ignore such considerations and calculate the contributions to non-standard-model triboson gauge couplings without such suppressions, using the first term in the momentum expansion of an effective chiral Lagrangian. It is found that at Fermilab Tevatron energies the two approaches do not differ much in quantitative results, while at large Hadron Collider (LHC) energies the two approaches give significantly different predictions for production rates. At the Tevatron and LHC, however, the sensitivity limits on the anomalous coupling of WWγ are too weak to usefully constrain parameters in the chiral Lagrangian.
Diagnosing Anomalous Network Performance with Confidence
Settlemyer, Bradley W; Hodson, Stephen W; Kuehn, Jeffery A; Poole, Stephen W
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 human behavior detection: an adaptive approach
NASA Astrophysics Data System (ADS)
van Leeuwen, Coen; Halma, Arvid; Schutte, Klamer
2013-05-01
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 behavior in videos from DARPA's Mind's Eye program, containing a variety of human activities. In this semi-unsupervised task a set of normal instances is provided for training, after which unknown abnormal behavior has to be detected in a test set. The features extracted from the video data have high dimensionality, are sparse and inhomogeneously distributed in the feature space making it a challenging task. Given these characteristics a distance-based method is preferred, but choosing a threshold to classify instances as (ab)normal is non-trivial. Our novel aproach, the Adaptive Outlier Distance (AOD) is able to detect outliers in these conditions based on local distance ratios. The underlying assumption is that the local maximum distance between labeled examples is a good indicator of the variation in that neighborhood, and therefore a local threshold will result in more robust outlier detection. We compare our method to existing state-of-art methods such as the Local Outlier Factor (LOF) and the Local Distance-based Outlier Factor (LDOF). The results of the experiments show that our novel approach improves the quality of the anomaly detection.
Dissipation of anomalous pressures in the subsurface
NASA Astrophysics Data System (ADS)
Muggeridge, Ann; Abacioglu, Yafes; England, William; Smalley, Craig
2004-11-01
Zones of anomalous pressure, higher and lower than hydrostatic pressure, have been observed in many sedimentary basins around the world. These normally consist of groups of pressure compartments: volumes of higher-permeability rock surrounded on all sides by lower-permeability barriers. Knowledge of the timescales over which these abnormal pressures are maintained and the mechanisms by which they dissipate is critical for understanding how fluids, such as oil and gas, move in the subsurface. Existing analytic solutions investigate pressure dissipation through low-permeability barriers on top of or underneath an isolated pressure compartment. There are no analytic solutions describing pressure dissipation through lateral barriers, such as faults, or investigating the impact of groups of pressure compartments on the rate of pressure dissipation. This paper presents simple analytic models to investigate pressure dissipation through barriers, such as faults, forming the sides of pressure compartments. The timescales are compared with a solution for pressure dissipation through barriers on top of and underneath the compartment. It also investigates analytically the rate of pressure dissipation from groups of pressure compartments. Lateral seal permeabilities of 10-19 m2 may delay pressure equilibration for millions of years provided the compartment has a sufficiently high fluid storage capacity. Factors contributing toward a high fluid storage capacity include a high fluid compressibility (as is the case in hydrocarbon reservoirs) and a high porosity. The grouping of abnormally pressured compartments into "megacompartment complexes" may delay pressure dissipation for hundreds of millions of years.
Hydrodynamic waves in an anomalous charged fluid
NASA Astrophysics Data System (ADS)
Abbasi, Navid; Davody, Ali; Hejazi, Kasra; Rezaei, Zahra
2016-11-01
We study the collective excitations in a relativistic fluid with an anomalous U (1) current. In 3 + 1 dimensions at zero chemical potential, in addition to ordinary sound modes we find two propagating modes in presence of an external magnetic field. The first one which is a transverse degenerate mode, propagates with a velocity proportional to the coefficient of gravitational anomaly; this is in fact the Chiral Alfvén wave recently found in [1]. Another one is a wave of density perturbation, namely a chiral magnetic wave (CMW). The velocity dependence of CMW on the chiral anomaly coefficient is well known. We compute the dependence of CMW's velocity on the coefficient of gravitational anomaly as well. We also show that the dissipation splits the degeneracy of CAW. At finite chiral charge density we show that in general there may exist five chiral hydrodynamic waves. Of these five waves, one is the CMW while the other four are mixed Modified Sound-Alfvén waves. It turns out that in propagation transverse to the magnetic field no anomaly effect appears while in parallel to the magnetic field we find sound waves become dispersive due to anomaly.
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
Anomalous diffusion on the Hanoi networks
NASA Astrophysics Data System (ADS)
Boettcher, S.; Gonçalves, B.
2008-11-01
Diffusion is modeled on the recently proposed Hanoi networks by studying the mean-square displacement of random walks with time, langr2rang~t2/dw. It is found that diffusion —the quintessential mode of transport throughout Nature— proceeds faster than ordinary, in one case with an exact, anomalous exponent dw=2- log2(phi)=1.30576... . It is an instance of a physical exponent containing the "golden ratio"\\phi=(1+\\sqrt{5})/2 that is intimately related to Fibonacci sequences and since Euclid's time has been found to be fundamental throughout geometry, architecture, art, and Nature itself. It originates from a singular renormalization group fixed point with a subtle boundary layer, for whose resolution phi is the main protagonist. The origin of this rare singularity is easily understood in terms of the physics of the process. Yet, the connection between network geometry and the emergence of phi in this context remains elusive. These results provide an accurate test of recently proposed universal scaling forms for first passage times.
Anomalous Oxidative Diffusion in Titanium Pyrotechnic Powders
Erikson, William W.; Coker, Eric N.
2016-11-10
It has long been observed that oxidation processes in metals tend to follow a parabolic rate law associated with the growth of a surface oxide layer. Here we observe that for certain titanium powders, the expected parabolic law (∝t_{1/2}) is recovered, yet for others, the exponent differs significantly. One explanation for this non-parabolic, anomalous diffusion arises from fractal geometry. Theoretical considerations indicate that the time response of diffusion-limited processes in an object closely follow a power-law in time (t^{n}) with n=(E–D)/2, where E is the object's Euclidean dimension and D is its boundary's Hausdorff dimension. Non-integer, (fractal) values of D will result in n≠1/2. Finite element simulations of several canonical fractal objects were performed to verify the application of this theory; the results matched the theory well. Two different types of titanium powder were tested in isothermal thermogravimetric tests under dilute oxygen. Time-dependent mass uptake data were fit with power-law forms and the associated exponents were used to determine an equivalent fractal dimension. One Ti powder type has an implied surface dimension of ca. 2.3 to 2.5, suggesting fractal geometry may be operative. Finally, the other has a dimension near 2.0, indicating it behaves like traditional material.
Anomalous Oxidative Diffusion in Titanium Pyrotechnic Powders
Erikson, William W.; Coker, Eric N.
2016-11-10
It has long been observed that oxidation processes in metals tend to follow a parabolic rate law associated with the growth of a surface oxide layer. Here we observe that for certain titanium powders, the expected parabolic law (∝t1/2) is recovered, yet for others, the exponent differs significantly. One explanation for this non-parabolic, anomalous diffusion arises from fractal geometry. Theoretical considerations indicate that the time response of diffusion-limited processes in an object closely follow a power-law in time (tn) with n=(E–D)/2, where E is the object's Euclidean dimension and D is its boundary's Hausdorff dimension. Non-integer, (fractal) values of Dmore » will result in n≠1/2. Finite element simulations of several canonical fractal objects were performed to verify the application of this theory; the results matched the theory well. Two different types of titanium powder were tested in isothermal thermogravimetric tests under dilute oxygen. Time-dependent mass uptake data were fit with power-law forms and the associated exponents were used to determine an equivalent fractal dimension. One Ti powder type has an implied surface dimension of ca. 2.3 to 2.5, suggesting fractal geometry may be operative. Finally, the other has a dimension near 2.0, indicating it behaves like traditional material.« less
Quantum anomalous Hall state in bilayer graphene
NASA Astrophysics Data System (ADS)
Nandkishore, Rahul; Levitov, Leonid
2010-09-01
We present a symmetry-based analysis of competition between different gapped states that have been proposed in bilayer graphene (BLG), which are all degenerate on a mean-field level. We classify the states in terms of a hidden SU(4) symmetry, and distinguish symmetry-protected degeneracies from accidental degeneracies. One of the states, which spontaneously breaks discrete time-reversal symmetry but no continuous symmetry, is identified as a quantum anomalous Hall (QAH) state, which exhibits quantum Hall effect at zero magnetic field. We investigate the lifting of the accidental degeneracies by thermal and zero-point fluctuations, taking account of the modes softened under renormalization group (RG). Working in a “saddle point plus quadratic fluctuations” approximation, we identify two types of RG-soft modes which have competing effects. Zero-point fluctuations, dominated by “transverse” modes which are unique to BLG, favor the QAH state. Thermal fluctuations, dominated by “longitudinal” modes, favor a SU(4) symmetry-breaking multiplet of states. We discuss the phenomenology and experimental signatures of the QAH state in BLG, and also propose a way to induce the QAH state using weak external magnetic fields.
Anomalous diffusion in rotating stratified turbulence
NASA Astrophysics Data System (ADS)
Kimura, Yoshi; Herring, Jackson
2006-11-01
Diffusion in rotating and stratified fluids is one of the central subjects in geophysical and astrophysical dynamics. In this paper, we report features of the dispersion of Lagrangian fluid particles in rotating stratified flows using the Direct Numerical Simulations (DNS) of the Navier-Stokes equations. And for calculation of particle dispersion, we use the cubic spline interpolation method by Yeung and Pope. Our main concern is the picture different from the Taylor dispersion theory, i.e.
An anomalous behavior of trypsin immobilized in alginate network.
Ganachaud, Chrystelle; Bernin, Diana; Isaksson, Dan; Holmberg, Krister
2013-05-01
Alginate is a biopolymer used in drug formulations and for surgical purposes. In the presence of divalent cations, it forms solid gels, and such gels are of interest for immobilization of cells and enzymes. In this work, we entrapped trypsin in an alginate gel together with a known substrate, N α-benzoyl-L-arginine-4-nitroanilide hydrochloride (L-BAPNA), and in the presence or absence of D-BAPNA, which is known to be a competitive inhibitor. Interactions between alginate and the substrate as well as the enzyme were characterized with transmission electron microscopy, rheology, and nuclear magnetic resonance spectroscopy. The biocatalysis was monitored by spectrophotometry at temperatures ranging from 10 to 42 °C. It was found that at 37 and 42 °C a strong acceleration of the reaction was obtained, whereas at 10 °C and at room temperature, the presence of D-BAPNA leads to a retardation of the reaction rate. The same effect was found when the reaction was performed in a non-cross-linked alginate solution. In alginate-free buffer solution, as well as in a solution of carboxymethylcellulose, a biopolymer that resembles alginate, the normal behavior was obtained; however, with D-BAPNA acting as an inhibitor at all temperatures. A more detailed investigation of the reaction kinetics showed that at higher temperature and in the presence of alginate, the curve of initial reaction rate versus L-BAPNA concentration had a sigmoidal shape, indicating an allosteric behavior. We believe that the anomalous behavior of trypsin in the presence of alginate is due to conformational changes caused by interactions between the positively charged trypsin and the strongly negatively charged alginate.
In-plane magnetization-induced quantum anomalous Hall effect.
Liu, Xin; Hsu, Hsiu-Chuan; Liu, Chao-Xing
2013-08-23
The quantum Hall effect can only be induced by an out-of-plane magnetic field for two-dimensional electron gases, and similarly, the quantum anomalous Hall effect has also usually been considered for systems with only out-of-plane magnetization. In the present work, we predict that the quantum anomalous Hall effect can be induced by in-plane magnetization that is not accompanied by any out-of-plane magnetic field. Two realistic two-dimensional systems, Bi2Te3 thin film with magnetic doping and HgMnTe quantum wells with shear strains, are presented and the general condition for the in-plane magnetization-induced quantum anomalous Hall effect is discussed based on the symmetry analysis. Nonetheless, an experimental setup is proposed to confirm this effect, the observation of which will pave the way to search for the quantum anomalous Hall effect in a wider range of materials.
Linear Magnetization Dependence of the Intrinsic Anomalous Hall Effect
Zeng, C.; Yao, Y.; Niu, Q.; Weitering, Harm H
2006-01-01
The anomalous Hall effect is investigated experimentally and theoretically for ferromagnetic thin films of Mn{sub 5}Ge{sub 3}. We have separated the intrinsic and extrinsic contributions to the experimental anomalous Hall effect and calculated the intrinsic anomalous Hall conductivity from the Berry curvature of the Bloch states using first-principles methods. The intrinsic anomalous Hall conductivity depends linearly on the magnetization, which can be understood from the long-wavelength fluctuations of the spin orientation at finite temperatures. The quantitative agreement between theory and experiment is remarkably good, not only near 0 K but also at finite temperatures, up to about -240 K (0.8T{sub c}).
Sampling and Characterization of 618-2 Anomalous Material
A.E. Zacharias
2006-04-27
Excavation of the 618-2 Burial Ground has produced many items of anomalous waste. Prior to temporary packaging and/or storage, these items have been characterized in the field to identify radiological and industrial safety conditions.
Anomalous scaling of a scalar field advected by turbulence
Kraichnan, R.H.
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.
The Chelyabinsk Meteorite Hits an Anomalous Zone in the Urals
NASA Astrophysics Data System (ADS)
Kochemasov, G. G.
2013-09-01
The Chelyabinsk meteorite is "strange" because it hits an area in the Urals where anomalous events are observed: shining skies, light balls, UFOs, electrphonic bolids. The area tectonically occurs at the intersection of two fold belts: Urals and Timan.
Apparatus for responding to an anomalous change in downhole pressure
Hall, David R.; Fox, Joe; Wilde, Tyson; Barlow, Jonathan S.
2010-04-13
A method of responding to an anomalous change in downhole pressure in a bore hole comprises detecting the anomalous change in downhole pressure, sending a signal along the segmented electromagnetic transmission path, receiving the signal, and performing a automated response. The anomalous change in downhole pressure is detected at a first location along a segmented electromagnetic transmission path, and the segmented electromagnetic transmission path is integrated into the tool string. The signal is received by at least one receiver in communication with the segmented electromagnetic transmission path. The automated response is performed along the tool string. Disclosed is an apparatus for responding to an anomalous change in downhole pressure in a downhole tool string, comprising a segmented electromagnetic transmission path connecting one or more receivers and at least one pressure sensor.
Method for processing seismic data to identify anomalous absorption zones
Taner, M. Turhan
2006-01-03
A method is disclosed for identifying zones anomalously absorptive of seismic energy. The method includes jointly time-frequency decomposing seismic traces, low frequency bandpass filtering the decomposed traces to determine a general trend of mean frequency and bandwidth of the seismic traces, and high frequency bandpass filtering the decomposed traces to determine local variations in the mean frequency and bandwidth of the seismic traces. Anomalous zones are determined where there is difference between the general trend and the local variations.
Anomalous left coronary artery from pulmonary artery with mitral stenosis.
Das, Mrinalendu; Mahindrakar, Pallavi; Das, Debasis; Behera, Sukanta Kumar; Chowdhury, Saibal Roy; Bandyopadhyay, Biswajit
2011-08-01
The usual presentation of anomalous left coronary artery from pulmonary artery is severe left-sided heart failure and mitral valve insufficiency presenting during the first months of life. The manifestations of left heart failure may be masked if pulmonary artery pressure remains high. We believe this is a rarest of rare case of anomalous left coronary artery from pulmonary artery with severe mitral stenosis and pulmonary hypertension in which pulmonary hypertension, along with good collateral circulation helped to preserve left ventricular function.
Large anomalous Nernst effect in a skyrmion crystal
NASA Astrophysics Data System (ADS)
Mizuta, Yo Pierre; Ishii, Fumiyuki
2016-06-01
Thermoelectric properties of a model skyrmion crystal were theoretically investigated, and it was found that its large anomalous Hall conductivity, corresponding to large Chern numbers induced by its peculiar spin structure leads to a large transverse thermoelectric voltage through the anomalous Nernst effect. This implies the possibility of finding good thermoelectric materials among skyrmion systems, and thus motivates our quests for them by means of the first-principles calculations as were employed in this study.
Large anomalous Nernst effect in a skyrmion crystal
Mizuta, Yo Pierre; Ishii, Fumiyuki
2016-01-01
Thermoelectric properties of a model skyrmion crystal were theoretically investigated, and it was found that its large anomalous Hall conductivity, corresponding to large Chern numbers induced by its peculiar spin structure leads to a large transverse thermoelectric voltage through the anomalous Nernst effect. This implies the possibility of finding good thermoelectric materials among skyrmion systems, and thus motivates our quests for them by means of the first-principles calculations as were employed in this study. PMID:27306142
Self-similar Turing patterns: An anomalous diffusion consequence
NASA Astrophysics Data System (ADS)
Hernández, D.; Herrera-Hernández, E. C.; Núñez-López, M.; Hernández-Coronado, H.
2017-02-01
In this work, we show that under specific anomalous diffusion conditions, chemical systems can produce well-ordered self-similar concentration patterns through diffusion-driven instability. We also find spiral patterns and patterns with mixtures of rotational symmetries. The type of anomalous diffusion discussed in this work, either subdiffusion or superdiffusion, is a consequence of the medium heterogeneity, and it is modeled through a space-dependent diffusion coefficient with a power-law functional form.
Searching for the fourth family quarks through anomalous decays
Sahin, M.; Sultansoy, S.; Turkoz, S.
2010-09-01
The flavor democracy hypothesis predicts the existence of the fourth standard model family. Because of the high masses of the fourth family quarks, their anomalous decays could be dominant if certain criteria are met. This will drastically change the search strategy at hadron colliders. We show that the fourth standard model family down quarks with masses up to 400-450 GeV can be observed (or excluded) via anomalous decays by Tevatron.
Self-similar Turing patterns: An anomalous diffusion consequence.
Hernández, D; Herrera-Hernández, E C; Núñez-López, M; Hernández-Coronado, H
2017-02-01
In this work, we show that under specific anomalous diffusion conditions, chemical systems can produce well-ordered self-similar concentration patterns through diffusion-driven instability. We also find spiral patterns and patterns with mixtures of rotational symmetries. The type of anomalous diffusion discussed in this work, either subdiffusion or superdiffusion, is a consequence of the medium heterogeneity, and it is modeled through a space-dependent diffusion coefficient with a power-law functional form.
Symmetrized local co-registration optimization for anomalous change detection
Wohlberg, Brendt E; Theiler, James P
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.
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.
Crossover from normal to anomalous diffusion in systems of field-aligned dipolar particles.
Jordanovic, Jelena; Jäger, Sebastian; Klapp, Sabine H L
2011-01-21
Using molecular dynamics simulations we investigate the translational dynamics of particles with dipolar interactions in homogenous external fields. For a broad range of concentrations, we find that the anisotropic, yet normal diffusive behavior characterizing weakly coupled systems becomes anomalous both parallel and perpendicular to the field at sufficiently high dipolar coupling and field strength. After the ballistic regime, chain formation first yields cagelike motion in all directions, followed by transient, mixed diffusive-superdiffusive behavior resulting from cooperative motion of the chains. The enhanced dynamics disappears only at higher densities close to crystallization.
Electron Anomalous Magnetic Moment in Basis Light-Front Quantization Approach
Zhao, Xingbo; Honkanen, Heli; Maris, Pieter; Vary, James P.; Brodsky, Stanley J.; /SLAC
2012-02-17
We apply the Basis Light-Front Quantization (BLFQ) approach to the Hamiltonian field theory of Quantum Electrodynamics (QED) in free space. We solve for the mass eigenstates corresponding to an electron interacting with a single photon in light-front gauge. Based on the resulting non-perturbative ground state light-front amplitude we evaluate the electron anomalous magnetic moment. The numerical results from extrapolating to the infinite basis limit reproduce the perturbative Schwinger result with relative deviation less than 1.2%. We report significant improvements over previous works including the development of analytic methods for evaluating the vertex matrix elements of QED.
Photon equation of motion with application to the electron's anomalous magnetic moment
Ritchie, A B
2007-12-06
The photon equation of motion previously applied to the Lamb shift is here applied to the anomalous magnetic moment of the electron. Exact agreement is obtained with the QED result of Schwinger. The photon theory treats the radiative correction to the photon in the presence of the electron rather than its inverse as in standard QED. The result is found to be first-order in the photon-electron interaction rather than second-order as in standard QED, introducing an ease of calculation hitherto unavailable.
Anomalous coupling, top-mass and parton-shower effects in W + W - production
NASA Astrophysics Data System (ADS)
Bellm, J.; Gieseke, S.; Greiner, N.; Heinrich, G.; Plätzer, S.; Reuschle, C.; von Soden-Fraunhofen, J. F.
2016-05-01
We calculate the process ppto {W}+{W}-to {e}+{ν}_e{μ}-{overline{ν}}_{μ } at NLO QCD, including also effective field theory (EFT) operators mediating the ggW + W - interaction, which first occur at dimension eight. We further combine the NLO and EFT matrix elements produced by G oS am with the H erwig7/M atchbox framework, which offers the possibility to study the impact of a parton shower. We assess the effects of the anomalous couplings by comparing them to top-mass effects as well as uncertainties related to variations of the renormalisation, factorisation and hard shower scales.
Anomalous vortex state of superconducting LuNi2B2C
NASA Astrophysics Data System (ADS)
Price, A. N.; Miller, R. I.; Kiefl, R. F.; Chakhalian, J. A.; Dunsiger, S. R.; Morris, G. D.; Sonier, J. E.; Canfield, P. C.
2002-06-01
Muon spin rotation has been used to investigate the magnetic-field distribution in the vortex state of superconducting LuNi2B2C (Tc~16 K). Data for the magnetic field range 0.06Hc2<~H<~0.23Hc2 are fitted to a nonlocal London model. The temperature dependence of the vortex core radius shows a clear Kramer-Pesch effect due to depopulation of bound states within the cores. Also, the penetration depth and core radius vary substantially with applied magnetic field, suggesting the presence of anomalous field-induced quasiparticles and vortex-vortex interactions.
Anomalous screening in two-dimensional materials with an extremum ring in the dispersion law
NASA Astrophysics Data System (ADS)
Kolomeisky, Eugene B.; Straley, Joseph P.
2016-12-01
A variety of two-dimensional materials possess a band structure with an energy extremal ridge along a ring in momentum space. Examples are biased bilayer graphene and surfaces and interfaces with a Rashba spin-orbit interaction where at low doping the carriers fill an annulus. This topological feature causes an anomalous screening behavior, which we study using the Thomas-Fermi theory. Specifically, reducing the doping is predicted to enhance the linear screening response, whereas at zero doping the size of the screening cloud surrounding a Coulomb impurity is found to increase as the cube root of the impurity charge.
Quantifying the Magnitude of Anomalous Solar Absorption
Ackerman, Thomas P.; Flynn, Donna M.; Marchand, Roger T.
2003-05-16
The data set from ARESE II, sponsored by the Atmospheric Radiation Measurement Program, provides a unique opportunity to understand solar absorption in the atmosphere because of the combination of three sets of broadband solar radiometers mounted on the Twin Otter aircraft and the ground based instruments at the ARM Southern Great Plains facility. In this study, we analyze the measurements taken on two clear sky days and three cloudy days and model the solar radiative transfer in each case with two different models. On the two clear days, the calculated and measured column absorptions agree to better than 10 Wm-2, which is about 10% of the total column absorption. Because both the model fluxes and the individual radiometer measurements are accurate to no better than 10 Wm-2, we conclude that the models and measurements are essentially in agreement. For the three cloudy days, the model calculations agree very well with each other and on two of the three days agree with the measurements to 20 Wm-2 or less out of a total column absorption of more than 200 Wm-2, which is again agreement at better than 10%. On the third day, the model and measurements agree to either 8% or 14% depending on which value of surface albedo is used. Differences exceeding 10% represent a significant absorption difference between model and observations. In addition to the uncertainty in absorption due to surface albedo, we show that including aerosol with an optical depth similar to that found on clear days can reduce the difference between model and measurement by 5% or more. Thus, we conclude that the ARESE II results are incompatible with previous studies reporting extreme anomalous absorption and can be modeled with our current understanding of radiative transfer.
Anomalous thermal conductivity of monolayer boron nitride
NASA Astrophysics Data System (ADS)
Tabarraei, Alireza; Wang, Xiaonan
2016-05-01
In this paper, we use nonequilibrium molecular dynamics modeling to investigate the thermal properties of monolayer hexagonal boron nitride nanoribbons under uniaxial strain along their longitudinal axis. Our simulations predict that hexagonal boron nitride shows an anomalous thermal response to the applied uniaxial strain. Contrary to three dimensional materials, under uniaxial stretching, the thermal conductivity of boron nitride nanoribbons first increases rather than decreasing until it reaches its peak value and then starts decreasing. Under compressive strain, the thermal conductivity of monolayer boron nitride ribbons monolithically reduces rather than increasing. We use phonon spectrum and dispersion curves to investigate the mechanism responsible for the unexpected behavior. Our molecular dynamics modeling and density functional theory results show that application of longitudinal tensile strain leads to the reduction of the group velocities of longitudinal and transverse acoustic modes. Such a phonon softening mechanism acts to reduce the thermal conductivity of the nanoribbons. On the other hand, a significant increase in the group velocity (stiffening) of the flexural acoustic modes is observed, which counteracts the phonon softening effects of the longitudinal and transverse modes. The total thermal conductivity of the ribbons is a result of competition between these two mechanisms. At low tensile strain, the stiffening mechanism overcomes the softening mechanism which leads to an increase in the thermal conductivity. At higher tensile strain, the softening mechanism supersedes the stiffening and the thermal conductivity slightly reduces. Our simulations show that the decrease in the thermal conductivity under compressive strain is attributed to the formation of buckling defects which reduces the phonon mean free path.
COS FUV Recovery after Anomalous Shutdown
NASA Astrophysics Data System (ADS)
Wheeler, Thomas
2012-10-01
This proposal consists of the steps for turning on and ramping up the COS FUV high voltage in a conservative manner after a HV anomalous shutdown by executing a "reduced set" of visits from Cycle 19 Proposal 12810. The nature of the shutdown, i.e., over-light, HV current transient {"crackle"}, ion feedback {induced by a high energy particle}, or field emission {possibly caused by dust or other particulate on the QE grid or other close-by structure or hardware}, and the value of the commanded HV at the time of the shutdown will determine what visits are executed. Because of gain sag, commanded HV settings updates may be required. First, prior to execution of this proposal or selected visits from this proposal, all preliminary steps should be exercised to gather the necessary diagnostic data, e.g., science data evaluation {if a science exposure was in progress and the science data is available}, memory dumps {DCE, EXEC RAM, and possibly the CS BUFFER}, engineering telemetry, or other information that might provide insight as to the nature of the shutdown and estimated count rate. The complete step-by-step procedure is detailed in the Observing Description, but in summary, the following is done:Day 01 activities, visits 01-07, contain both QE grid off and on HV ramping to HVLow {100/100} with diagnostics {DCE dumps} and darks to exclude QE grid involvement in the shutdown. Subsequent to day 01, all HV ramping will be with the QE grid on with the same diagnostics and exposures. All days end with the setting of COS event flag 3 to prevent any FUV HV commanding.Time is allotted for cognizant detector and COS instrument scientist and engineers to examine data dumps, science exposures, and engineering telemetry. If all is well, the go-ahead will be given to clear flag 3 for the next day's visits.This proposal is modeled after the Cycle 19 Proposal 12718.
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.
2016-01-01
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. PMID:26960122
Constraints on anomalous HVV couplings of the Higgs boson in proton collisions at 7 and 8 TeV
NASA Astrophysics Data System (ADS)
Martin, Christopher; CMS Collaboration
2015-04-01
Under the hypothesis that the resonance is a spin-zero boson, the tensor structure of the interactions of the recently discovered Higgs boson is performed using the H --> ZZ , Zγ* ,γ*γ* --> 4 l and H --> WW --> lνlν decay modes. The full dataset recorded by the CMS experiment during the LHC Run 1 is used, corresponding to an integrated luminosity of up to 5 . 1fb-1 at a center-of-mass energy of 7 TeV and up to 19 . 7fb-1 at 8 TeV . Limits on eleven anomalous contributions are set. Tighter constraints on anomalous HVV interactions are obtained by combining the HZZ and HWW measurements. All observations are consistent with the expectations for the standard model Higgs boson with the quantum numbers JPC =0++ .
Anomalous magnetism of Pr in PrCoAsO
Tiwari, Brajesh; Awana, V. P. S.; Pal, Anand
2014-01-15
Detailed magnetization and magneto-transport measurements studies are carried out to unearth the anomalous magnetism of Pr in PrCoAsO compound. The studied PrCoAsO sample is single phase and crystallized in the tetragonal structure with space group P4/nmm in analogy of ZrCuSiAs type compounds. Detailed magnetization measurements showed that Co moments in PrCoAsO exhibit weakly itinerant ferromagnetic Co spins ordering at below 80 K with a small magnetic moments of ∼ 0.12 μ{sub B}/f.u. High temperatures Curie-Weiss fit, resulted in effective paramagnetic moment μ{sub eff} (exp) of 5.91 μ{sub B}/f.u., which can be theoretically assigned to 3d Co (3.88 μ{sub B}) and 4f Pr (3.58 μ{sub B}). Further, a positive Curie-Weiss temperature (Θ) of 136 K is seen, indicating predominant ferromagnetic interactions in PrCoAsO. Detailed transport measurements showed that PrCoAsO exhibit metallic behavior and negative magneto-resistance below ferro-magnetically (FM) ordered state. Surprisingly, the situation of PrCoAsO is similar to non magnetic La containing LaCoAsO and strikingly different than that as reported for magnetic Nd, Sm and Gd i.e., (Nd/Sm/Gd)CoAsO. The magnetic behavior of PrCoAsO being closed to LaCoAsO and strikingly different to that of (Nd/Sm/Gd)CoAsO is unusual.
Anomalously small blackbody radiation shift in the Tl+ frequency standard
NASA Astrophysics Data System (ADS)
Zuhrianda, Z.; Safronova, M. S.; Kozlov, M. G.
2012-02-01
The operation of atomic clocks is generally carried out at room temperature, whereas the definition of the second refers to the clock transition in an atom at absolute zero. This implies that the clock transition frequency should be corrected in practice for the effect of finite temperature of which the leading contributor is the blackbody radiation (BBR) shift. In the present work, we used configuration interaction + coupled-cluster method to evaluate polarizabilities of the 6s21S0 and 6s6p3P0 states of the Tl+ ion; we find α0(1S0)=19.6 a.u. and α0(3P0)=21.4 a.u. The resulting BBR shift of the 6s6p3P0-6s21S0 Tl+ transition at 300 K is ΔνBBR=-0.0157(16) Hz. This result demonstrates that near cancellation of the 1S0 and 3P0 state polarizabilities in divalent B+, Al+, and In+ ions of group IIIB [M. S. Safronova , Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.107.143006 107, 143006 (2011)] continues for much heavier Tl+, leading to anomalously small BBR shift for this system. This calculation demonstrates that the BBR contribution to the fractional frequency uncertainty of the Tl+ frequency standard at 300 K is 1×10-18. We find that Tl+ has the smallest fractional BBR shift among all present or proposed frequency standards with the exception of Al+.
COS FUV Recovery after Anomalous Shutdown
NASA Astrophysics Data System (ADS)
Wheeler, Thomas
2013-10-01
This proposal consists of the steps for turning on and ramping up the COS FUV high voltage in a safe and conservative manner after a HV anomalous shutdown by executing a "reduced set" of visits from Cycle 19 Proposal 12810. The nature of the shutdown, i.e., over-light, HV current transient {"crackle"}, ion feedback {induced by a high energy particle}, or field emission {possibly caused by dust or other particulate on the QE grid or other close-by structure or hardware}, and the value of the commanded HV at the time of the shutdown will determine what visits are executed. Because of gain sag, commanded HV settings updates may be required. First, prior to execution of this proposal or selected visits from this proposal, all preliminary steps should be exercised to gather the necessary diagnostic data, e.g., science data evaluation {if a science exposure was in progress and the science data is available}, memory dumps {DCE, EXEC RAM, and possibly the CS BUFFER}, engineering telemetry, or other information that might provide insight as to the nature of the shutdown and estimated count rate. The complete step-by-step procedure is detailed in the Observing Description, but in summary, the following is done:Day 01 activities, visits 01-07, contain both QE grid off and on HV ramping to HVLow {100/100} with diagnostics {DCE dumps} and darks to exclude QE grid involvement in the shutdown. Subsequent to day 01, all HV ramping will be with the QE grid on with the same diagnostics and exposures. All days end with the setting of COS event flag 3 to prevent any FUV HV commanding.Time is allotted for cognizant detector and COS instrument scientist and engineers to examine data dumps, science exposures, and engineering telemetry. If all is well, the go-ahead will be given to clear flag 3 for the next day's visits.This proposal is modeled after the Cycle 20 Proposal 13129.
Anomalous Moessbauer Fraction in Superparamagnetic Systems.
NASA Astrophysics Data System (ADS)
Mohie-Eldin, Mohie-Eldin Yehia
The biological molecule ferritin and its proven synthetic counterpart polysaccharide iron complex (P.I.C.) have been shown to contain small (<100 ^circ in diameter) antiferromagnetic cores at their centers. Mossbauer studies of these molecules have revealed an anomalous drop in the Mossbauer fraction (f-factor) as the temperature rises above 30^ circK for mammalian ferritin and 60 ^circK for P.I.C. Above the blocking temperature, superparamagnetic relaxation results in the disappearance of hyperfine splitting. This thesis investigates and attempts to resolve this Lamb-Mossbauer f-Factor anomaly in these superparamagnetically relaxing systems. Chapter I deals with a basic review of theories of Mossbauer spectroscopy and superparamagnetism. The analogies in the composition of the two molecules is examined in Chapter II. The long range order technique of magnetization measurements is used in Chapter III to compare magnetic properties of both molecules and to verify the suggestion that the P.I.C. molecule is a good "biomimic" to ferritin based on the identification of ferrihydrite as the major mineral in both, by short range probing techniques such as X-ray diffraction. The anomaly is confirmed in P.I.C.'s Mossbauer spectra in Chapter IV. Different absorbers are used to experimentally investigate the absorber thickness effect on the Mossbauer spectra. The anomaly persists for thin absorbers. Also in Chapter V, data that is treated with FFT procedures to eliminate the thickness effect still exhibit this anomaly. We then investigated the effect of superparamagnetic relaxation on the f-factor. In Chapter VI, spin-lattice relaxation was excluded based upon a calculation of the rate of energy transfer from the spin system to the lattice. We introduce a theory in Chapter VII based on the following process as a plausible explanation of the anomaly: Superparamagnetic relaxation brings about a dynamical displacement of the Mossbauer nucleus through magnetostriction. These
Intraductal papillary neoplasm originating from an anomalous bile duct.
Maki, Harufumi; Aoki, Taku; Ishizawa, Takeaki; Tanaka, Mariko; Sakatani, Takashi; Beck, Yoshifumi; Hasegawa, Kiyoshi; Sakamoto, Yoshihiro; Kokudo, Norihiro
2017-02-17
An 82-year-old woman who had been suffering from repeated obstructive jaundice for 7 years was referred to our hospital. Although endoscopic aspiration of the mucin in the common bile duct had been temporally effective, origin of the mucin production had not been detectable. The patient thus had been forced to be on long-term follow-up without curative resection. Endoscopic retrograde cholangioscopy on admission revealed massive mucin in the common bile duct. In addition, an anomalous bile duct located proximal to the gallbladder was identified. Since the lumen of the anomalous duct was irregular and the rest of biliary tree was completely free of suspicious lesions, the anomalous duct was judged to be the primary site. Surgical resection of the segment 4 and 5 of the liver combined with the extrahepatic biliary tract was performed. Pathological diagnosis was compatible to intraductal papillary neoplasm with high-grade intraepithelial dysplasia of the anomalous bile duct. The patient has been free from the disease for 6.5 years after resection. This is the first case of intraductal papillary neoplasm derived from an anomalous bile duct, which was resected after long-term conservative treatment. The present case suggested the slow growing character of natural history of the neoplasm.
ANOMALOUS MICROWAVE EMISSION IN H ii REGIONS: IS IT REALLY ANOMALOUS? THE CASE OF RCW 49
Paladini, Roberta; Ingallinera, Adriano; Agliozzo, Claudia; Umana, Grazia; Trigilio, Corrado; Tibbs, Christopher T.; Noriega-Crespo, Alberto; Dickinson, Clive
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.
Leptophilic dark matter and the anomalous magnetic moment of the muon
Agrawal, Prateek; Chacko, Zackaria; Verhaaren, Christopher B.
2014-08-26
We consider renormalizable theories such that the scattering of dark matter off leptons arises at tree level, but scattering off nuclei only arises at loop. In this framework, the various dark matter candidates can be classified by their spins and by the forms of their interactions with leptons. In this study, we determine the corrections to the anomalous magnetic moment of the muon that arise from its interactions with dark matter. We then consider the implications of these results for a set of simplified models of leptophilic dark matter. When a dark matter candidate reduces the existing tension between themore » standard model prediction of the anomalous magnetic moment and the experimental measurement, the region of parameter space favored to completely remove the discrepancy is highlighted. Conversely, when agreement is worsened, we place limits on the parameters of the corresponding simplified model. These bounds and favored regions are compared against the experimental constraints on the simplified model from direct detection and from collider searches. Although these constraints are severe, we find there do exist limited regions of parameter space in these simple theories that can explain the observed anomaly in the muon magnetic moment while remaining consistent with all experimental bounds.« less
On the anomalous precipitation enhancement over the Himalayan foothills during monsoon breaks
NASA Astrophysics Data System (ADS)
Vellore, Ramesh K.; Krishnan, R.; Pendharkar, Jayant; Choudhury, Ayantika Dey; Sabin, T. P.
2014-10-01
An intriguing feature associated with `breaks' in the Indian summer monsoon is the occurrence of intense/flood-producing precipitation confined to central-eastern parts of the Himalayan (CEH) foothills and north-eastern parts of India. Past studies have documented various large-scale circulation aspects associated with monsoon-breaks, however the dynamical mechanisms responsible for anomalous precipitation enhancement over CEH foothills remain unclear. This problem is investigated using diagnostic analyses of observed and reanalysis products and high-resolution model simulations. The present findings show that the anomalous precipitation enhancement over the CEH foothills during monsoon-breaks emerges as a consequence of interactions between southward intruding mid-latitude westerly troughs and the South Asian monsoon circulation in its weak phase. These interactions facilitate intensification of mid-tropospheric cyclonic vorticity and strong ascending motion over the CEH foothills, so as to promote deep convection and concentrated rainfall activity over the region during monsoon-breaks. Mesoscale orographic effects additionally tend to amplify the vertical motions and precipitation over the CEH foothills as evidenced from the high-resolution model simulations. It is further noted from the model simulations that the coupling between precipitation and circulation during monsoon-breaks can produce nearly a threefold increase of total precipitation over the CEH foothills and neighborhood as opposed to active-monsoon conditions.
Anomalous random telegraph noise and temporary phenomena in resistive random access memory
NASA Astrophysics Data System (ADS)
Puglisi, Francesco Maria; Larcher, Luca; Padovani, Andrea; Pavan, Paolo
2016-11-01
In this paper we present a comprehensive examination of the characteristics of complex Random Telegraph Noise (RTN) signals in Resistive Random Access Memory (RRAM) devices with TiN/Ti/HfO2/TiN structure. Initially, the anomalous RTN (aRTN) is investigated through careful systematic experiment, dedicated characterization procedures, and physics-based simulations to gain insights into the physics of this phenomenon. The experimentally observed RTN parameters (amplitude of the current fluctuations, capture and emission times) are analyzed in different operating conditions. Anomalous behaviors are characterized and their statistical characteristics are evaluated. Physics-based simulations considering both the Coulomb interactions among different defects in the device and the possible existence of defects with metastable states are exploited to suggest a possible physical origin of aRTN. The same simulation framework is also shown to be able to predict other temporary phenomena related to RTN, such as the temporary change in RTN stochastic properties or the sudden and iterative random appearing and vanishing of RTN fluctuations always exhibiting the same statistical characteristics. Results highlight the central role of the electrostatic interactions among individual defects and the trapped charge in describing RTN and related phenomena.
Leptophilic dark matter and the anomalous magnetic moment of the muon
Agrawal, Prateek; Chacko, Zackaria; Verhaaren, Christopher B.
2014-08-26
We consider renormalizable theories such that the scattering of dark matter off leptons arises at tree level, but scattering off nuclei only arises at loop. In this framework, the various dark matter candidates can be classified by their spins and by the forms of their interactions with leptons. In this study, we determine the corrections to the anomalous magnetic moment of the muon that arise from its interactions with dark matter. We then consider the implications of these results for a set of simplified models of leptophilic dark matter. When a dark matter candidate reduces the existing tension between the standard model prediction of the anomalous magnetic moment and the experimental measurement, the region of parameter space favored to completely remove the discrepancy is highlighted. Conversely, when agreement is worsened, we place limits on the parameters of the corresponding simplified model. These bounds and favored regions are compared against the experimental constraints on the simplified model from direct detection and from collider searches. Although these constraints are severe, we find there do exist limited regions of parameter space in these simple theories that can explain the observed anomaly in the muon magnetic moment while remaining consistent with all experimental bounds.
Quantum anomalous Hall effect in magnetic insulator heterostructure.
Xu, Gang; Wang, Jing; Felser, Claudia; Qi, Xiao-Liang; Zhang, Shou-Cheng
2015-03-11
On the basis of ab initio calculations, we predict that a monolayer of Cr-doped (Bi,Sb)2Te3 and GdI2 heterostructure is a quantum anomalous Hall insulator with a nontrivial band gap up to 38 meV. The principle behind our prediction is that the band inversion between two topologically trivial ferromagnetic insulators can result in a nonzero Chern number, which offers a better way to realize the quantum anomalous Hall state without random magnetic doping. In addition, a simple effective model is presented to describe the basic mechanism of spin polarized band inversion in this system. Moreover, we predict that 3D quantum anomalous Hall insulator could be realized in (Bi2/3Cr1/3)2Te3 /GdI2 superlattice.
Observations of Anomalous Refraction with Co-housed Telescopes
NASA Astrophysics Data System (ADS)
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.
Searching for anomalous top quark production at the early LHC.
Gao, Jun; Li, Chong Sheng; Yang, Li Lin; Zhang, Hao
2011-08-26
We present a detailed study of the anomalous top quark production with subsequent decay at the LHC induced by model-independent flavor-changing neutral-current couplings, incorporating the complete next-to-leading order QCD effects. Our results show that, taking into account the current limits from the Tevatron, the LHC with √s=7 TeV may discover the anomalous coupling at 5σ level for a very low integrated luminosity of 61 pb⁻¹. The discovery potentials for the anomalous couplings at the LHC are examined in detail. We also discuss the possibility of using the charge ratio to distinguish the tug and tcg couplings.
Validity of anomalous diffraction approximation in m- χ domain
NASA Astrophysics Data System (ADS)
Liu, Chun-Lei
In a recent paper, Liu et al. [Liu, C., Jonas, P.R., Saunders, C.P.R., 1996. Accuracy of the anomalous diffraction approximation to the light scattering by column-like ice crystals. Atmos. Res. 41, 63-69] reported that the anomalous diffraction approximation (ADA) accuracy is not sensitive to van de Hulst's condition | m-1|≪1, but is dependent on the size parameter χ. Videen and Chýlek [Videen, G., Chýlek, P., 1998. Anomalous diffraction approximation limits. Atmos. Res., this issue] pointed out that this result is at odds with previous research, and their results indicated that the accuracy of ADA is much dependent on the condition of | m-1|≪1. Some calculated results are presented here to provide further discussion of the ADA validity in the calculation of particle extinction and absorption efficiencies.
Compositions of Normal and Anomalous Eucrite-Type Mafic Achondrites
NASA Technical Reports Server (NTRS)
Mittlefehldt, D. W.; Peng, Z. X.; Mertzman, S. A.
2016-01-01
The most common asteroidal igneous meteorites are eucrite-type mafic achondrites - basalts and gabbros composed of ferroan pigeonite, ferroan augite, calcic plagioclase, silica, ilmenite, troilite, Ca-phosphate, chromite and Fe-metal. These rocks are thought to have formed on a single asteroid along with howardites and diogenites. However, high precision O-isotopic analyses have shown that some mafic achondrites have small, well-resolved, non-mass-dependent differences that have been interpreted as indicating derivation from different asteroids. Some of these O-anomalous mafic achondrites also have anomalous petrologic characteristics, strengthening the case that they hail from distinct parent asteroids. We present the results of bulk compositional studies of a suite of normal and anomalous eucrite-type basalts and cumulate gabbros.
Partial anomalous pulmonary venous connection (including scimitar syndrome).
van de Woestijne, Pieter C; Verberkmoes, Niels; Bogers, Ad J J C
2013-01-01
Partial anomalous pulmonary venous connection (PAPVC) is defined to exist when some but not all venous drainage enters the left atrium, while the remaining veins connect to the right-sided circulation. Scimitar syndrome is a specialized example, in which an anomalous pulmonary vein descends from the right lung and drains into the inferior caval vein. PAPVC is associated with sinus venosus-type atrial septal defect (ASD). Diagnosis was, in the past, based on echocardiographic imaging and could be difficult. Multislice spiral computed tomography and magnetic resonance imaging improved the imaging quality. The surgical correction is dependent on the type of anomalous connection and the presence of an ASD. Outcome is good but obstructed venous return is an important issue.
Isotropic anomalous filtering in Diffusion-Weighted Magnetic Resonance Imaging.
da S Senra Filho, Antonio Carlos; Jinzenji Duque, Juliano; Murta Junior, Luiz Otávio
2013-01-01
Noise is inherent to Diffusion-Weighted Magnetic Resonance Imaging (DWI) and noise reduction methods are necessary. Although process based on classical diffusion is one of the most used approaches for digital image, anomalous diffusion has the potential for image enhancement and it has not been tested for DWI noise reduction. This study evaluates Anomalous Diffusion (AD) filter as DWI enhancement method. The proposed method was applied to magnetic resonance diffusion weighted images (DW-MRI) with different noise levels. Results show better performance for anomalous diffusion when compared to classical diffusion approach. The proposed method has shown potential in DWI enhancement and can be an important process to improve quality in DWI for neuroimage-based diagnosis.
Unique continuation property for the anomalous diffusion and its application
NASA Astrophysics Data System (ADS)
Cheng, Jin; Lin, Ching-Lung; Nakamura, Gen
The unique continuation for anomalous diffusion operators with fractional time derivative of order 1/2 is proved by deriving Carleman estimates for the operators. By applying operators which have a negative sign in front of the diffusion terms of anomalous diffusion operators, the anomalous diffusion operators are transformed to parabolic operators of order 4 in the space variables. The Carleman estimates are derived for these transformed operators considered as semi-elliptic operators. The usual Calderón uniqueness argument for semi-elliptic operators does not work due to the singularities in factors of the factorization of their principal parts. In order to have smooth factorizations of the operators, we took into account the lower order terms of the operators.
No-Drag Frame for Anomalous Chiral Fluid
Stephanov, Mikhail A.; Yee, Ho-Ung
2016-03-24
For an anomalous fluid carrying dissipationless chiral magnetic and/or vortical currents we show that there is a frame in which a stationary obstacle experiences no drag, but energy and charge currents do not vanish, resembling superfluidity. Unlike ordinary superfluid flow, the anomalous chiral currents can transport entropy in this frame. Moreover, we show that the second law of thermodynamics completely determines the amounts of these anomalous nondissipative currents in the “no-drag frame” as polynomials in temperature and chemical potential with known anomaly coefficients. These general results are illustrated and confirmed by a calculation in the chiral kinetic theory and inmore » the quark-gluon plasma at high temperature.« less
[Anomalous absorption and a qualified far infrared spectrum].
Hu, Yan-qin; Chen, Yu-jing; Li, Hui-hua; Wang, Hai-shui
2012-02-01
The ideal 100% line could not be obtained when the content of water vapor in the spectrometer is constant but high during the whole procedure of a far-infrared spectrum collection. This result indicates that anomalous absorption phenomenon takes place in high relative humidity atmosphere. In the present paper, the influences of the relative humidity of ambient air and spectral resolution on anomalous absorption were studied. It was found that both decreasing the water vapor content in the spectrometer and adopting low spectral resolution are effective methods to avoid anomalous absorption. Furthermore, the water vapor bands can be eliminated by "dry air and wet air titration" in the fluctuant humidity. This provides us a quick and economic method to obtain a qualified far infrared spectrum conveniently. It should be noticed that the working condition for "dry air and wet air titration" is low relative humidity to prevent water vapor abnormal absorption.
Limits on anomalous contributions to the Wtb vertex
NASA Astrophysics Data System (ADS)
Pease, Christopher; Fiolhais, Miguel; Onofre, Antonio
2017-01-01
Recent LHC results on the measurements of the W-boson helicity fractions and single top quark production cross section at a center-of-mass energy of 13 TeV are combined in order to establish new limits on anomalous contributions to the Wtb vertex. The allowed regions for these limits are presented in three-dimensional graphics, for both real and imaginary components of the different anomalous couplings, allowing all the other anomalous couplings to vary at the same time. These results are combined with the prospected future measurement of the single top quark production cross section and W-boson helicity fractions at the LHC. When compared with the previous most precise limits, these results show a significant improvement, larger than 10%.
Phenomenological Spin Transport Theory Driven by Anomalous Nernst Effect
NASA Astrophysics Data System (ADS)
Taniguchi, Tomohiro
2016-07-01
Several experimental efforts such as material investigation and structure improvement have been made recently to find a large anomalous Nernst effect in ferromagnetic metals. Here, we develop a theory of spin transport driven by the anomalous Nernst effect in a diffusive ferromagnetic/nonmagnetic multilayer. Starting from a phenomenological formula of a spin-dependent electric current, the theoretical formulas of electric voltage and spin torque generated by the anomalous Nernst effect are derived. The magnitude of the electric voltage generated from the spin current via the inverse spin Hall effect is on the order of 0.1 µV for currently available experimental parameter values. The temperature gradient necessary to switch the magnetization is quite larger than the typical experimental value. The separation of the contributions of the Seebeck and transverse spin Seebeck effects is also discussed.
Anomalous Hall effect in YIG|Pt bilayers
Meyer, Sibylle Schlitz, Richard; Geprägs, Stephan; Opel, Matthias; Huebl, Hans; Goennenwein, Sebastian T. B.; Gross, Rudolf
2015-03-30
We measure the ordinary and the anomalous Hall effect in a set of yttrium iron garnet|platinum (YIG|Pt) bilayers via magnetization orientation dependent magnetoresistance experiments. Our data show that the presence of the ferrimagnetic insulator YIG leads to an anomalous Hall effect like voltage in Pt, which is sensitive to both Pt thickness and temperature. Interpretation of the experimental findings in terms of the spin Hall anomalous Hall effect indicates that the imaginary part of the spin mixing conductance G{sub i} plays a crucial role in YIG|Pt bilayers. In particular, our data suggest a sign change in G{sub i} between 10 K and 300 K. Additionally, we report a higher order Hall effect contribution, which appears in thin Pt films on YIG at low temperatures.
Emergence of anomalous transport in stressed rough fractures
NASA Astrophysics Data System (ADS)
Kang, Peter K.; Brown, Stephen; Juanes, Ruben
2016-11-01
We report the emergence of anomalous (non-Fickian) transport through a rough-walled fracture as a result of increasing normal stress on the fracture. We show that the origin of this anomalous transport behavior can be traced to the emergence of a heterogeneous flow field dominated by preferential channels and stagnation zones, as a result of the larger number of contacts in a highly stressed fracture. We show that the velocity distribution determines the late-time scaling of particle spreading, and velocity correlation determines the magnitude of spreading and the transition time from the initial ballistic regime to the asymptotic anomalous behavior. We also propose a spatial Markov model that reproduces the transport behavior at the scale of the entire fracture with only three physical parameters. Our results point to a heretofore unrecognized link between geomechanics and particle transport in fractured media.
Anomalous absorption of laser light on ion acoustic fluctuations
NASA Astrophysics Data System (ADS)
Rozmus, Wojciech; Bychenkov, Valery Yu.
2016-10-01
Theory of laser light absorption due to ion acoustic turbulence (IAT) is discussed in high Z plasmas where ion acoustic waves are weakly damped. Our theory applies to the whole density range from underdense to critical density plasmas. It includes an absorption rate for the resonance anomalous absorption due to linear conversion of electromagnetic waves into electron plasma oscillations by the IAT near the critical density in addition to the absorption coefficient due to enhanced effective electron collisionality. IAT is driven by large electron heat flux through the return current instability. Stationary spectra of IAT are given by weak plasma turbulence theory and applied in description of the anomalous absorption in the inertial confinement fusion plasmas at the gold walls of a hohlraum. This absorption is anisotropic in nature due to IAT angular anisotropy and differs for p- and s-polarization of the laser radiation. Possible experiments which could identify the resonance anomalous absorption in a laser heated plasma are discussed.
A tutorial on inverse problems for anomalous diffusion processes
NASA Astrophysics Data System (ADS)
Jin, Bangti; Rundell, William
2015-03-01
Over the last two decades, anomalous diffusion processes in which the mean squares variance grows slower or faster than that in a Gaussian process have found many applications. At a macroscopic level, these processes are adequately described by fractional differential equations, which involves fractional derivatives in time or/and space. The fractional derivatives describe either history mechanism or long range interactions of particle motions at a microscopic level. The new physics can change dramatically the behavior of the forward problems. For example, the solution operator of the time fractional diffusion diffusion equation has only limited smoothing property, whereas the solution for the space fractional diffusion equation may contain weak singularity. Naturally one expects that the new physics will impact related inverse problems in terms of uniqueness, stability, and degree of ill-posedness. The last aspect is especially important from a practical point of view, i.e., stably reconstructing the quantities of interest. In this paper, we employ a formal analytic and numerical way, especially the two-parameter Mittag-Leffler function and singular value decomposition, to examine the degree of ill-posedness of several ‘classical’ inverse problems for fractional differential equations involving a Djrbashian-Caputo fractional derivative in either time or space, which represent the fractional analogues of that for classical integral order differential equations. We discuss four inverse problems, i.e., backward fractional diffusion, sideways problem, inverse source problem and inverse potential problem for time fractional diffusion, and inverse Sturm-Liouville problem, Cauchy problem, backward fractional diffusion and sideways problem for space fractional diffusion. It is found that contrary to the wide belief, the influence of anomalous diffusion on the degree of ill-posedness is not definitive: it can either significantly improve or worsen the conditioning of
Analysis of Diffraction Anomalous Fine Structure
NASA Astrophysics Data System (ADS)
Cross, Julie Olmsted
This thesis presents a systematic study of the application of DAFS to determine site-specific local structural and chemical information in complex materials, and the first application of state-of-the-art theoretical XAFS calculations using the computer program scFEFF to model DAFS data. In addition, the iterative dispersion analysis method, first suggested by Pickering, et al., has been generalized to accommodate the off-resonance anomalous scattering from heavy atoms in the unit cell. The generalized algorithm scKKFIT was applied to DAFS data from eight (00 l) reflections of the high-T _{c} superconductor YBa _2Cu_3O_ {6.8} to obtain the weighted complex resonant scattering amplitudes Delta f_{ rm w}(Q, E). The fine-structure functions chi_{rm w}(Q, E) isolated from the Delta f_{ rm w}(Q, E) are linear combinations of the individual site fine structure functions chi _{rm w}(Q, E) = Sigma_{i}W_{i,{ bf Q}}chi_{i}(E) from the two inequivalent Cu sites, added together according to the structure factor for the Cu sublattice. The chi_{rm w}(Q, E) were fit en masse using the XAFS analysis program scFEFFIT under a set of constraints on the coefficients W _{i,{bf Q}} based on the structure factor for kinematic scattering. The W_{i,{bf Q}} determined by scFEFFIT were used to obtain the fully separated complex resonant scattering amplitudes Delta f(E) for the two Cu sites. The theoretical connection between DAFS and XAFS is used to justify the application of state-of-the-art theoretical XAFS calculations to DAFS analysis. The polarization dependence of DAFS is described in terms of individual virtual photoelectron scattering paths in the Rehr-Albers separable curved-wave formalism. Polarization is shown to be an important factor in all DAFS experiments. Three experimental constraints are found necessary for obtaining site-separated Delta f(E) from DAFS data by linear inversion of the W_{i, {bf Q}} matrix and scKKFIT isolated Delta f_{rm w }(Q, E): (1) The diffraction must be
Test of an anomalous electromagnetic effect
NASA Astrophysics Data System (ADS)
Bartlett, D. F.; Maglic, Steven
1990-10-01
Sansbury has suggested and measured a new electromagnetic attraction between a current and a static charge. We have searched in vain for this interaction. The sensitivity of our measurement is roughly 5 times higher than that of the experiment in which the effect was originally seen.
A proposal for the origin of the anomalous magnetic moment
NASA Astrophysics Data System (ADS)
Novello, M.; Bittencourt, E.
2014-05-01
We investigate a new form of contribution for the anomalous magnetic moment of all particles. This common origin is displayed in the framework of a recent treatment of electrodynamics that is based on the introduction of an electromagnetic metric which has no gravitational character. This effective metric constitutes a universal pure electromagnetic process perceived by all bodies, charged or not charged. As a consequence, it yields a complementary explanation for the existence of anomalous magnetic moment for charged particles and even for noncharged ones like neutrinos.
Broken current anomalous dimensions, conformal manifolds, and renormalization group flows
NASA Astrophysics Data System (ADS)
Bashmakov, Vladimir; Bertolini, Matteo; Raj, Himanshu
2017-03-01
We consider deformations of a conformal field theory that explicitly break some global symmetries of the theory. If the deformed theory is still a conformal field theory, one can exploit the constraints put by conformal symmetry to compute broken currents anomalous dimensions. We consider several instances of this scenario, using field theory techniques and also holographic ones, where necessary. Field theoretical methods suffice to discuss examples of symmetry-breaking deformations of the O (N ) model in d =4 -ɛ dimensions. Holography is instrumental, instead, for computing current anomalous dimensions in β -deformed superconformal field theories and in a class of supersymmetric renormalization group flows at large N .
Algebraic isomorphism in two-dimensional anomalous gauge theories
Carvalhaes, C.G.; Natividade, C.P.
1997-08-01
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 {Theta}-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 temperature dependence of the IR spectrum of polyalanine
NASA Astrophysics Data System (ADS)
Helenius, V.; Korppi-Tommola, J.; Kotila, S.; Nieminen, J.; Lohikoski, R.; Timonen, J.
1997-12-01
We have studied the temperature dependence of the infrared spectra of acetanilide (ACN), tryptophan-(alanine) 15, and tyrosine-(alanine) 15. No sidebands of the amide-I vibration were observed in the polypeptides, but two anomalous sidebands of the NH stretch with a similar temperature dependence as that of the anomalous amide-I vibrational mode at 1650 cm -1 of crystalline ACN were detected. Fermi resonance combined with the appearance of a red-shifted sideband of NH stretch through coupling to lattice modes seems to explain this band structure. Observations are indicative of excitons that may occur in polypeptides as well as in single crystals of ACN.
The magnetic field in the anomalous arms in NGC 4258
NASA Astrophysics Data System (ADS)
Hummel, E.; Krause, M.; Beck, R.
The linearly polarized emission and total emission of NGC 4258 at 4.9 and 1.5 GHz were observed with the VLA in its D and C arrays respectively. The results strongly suggest that the anomalous arms are in the plane of NGC 4258, hence excluding models that require them to be out of the plane. The observed magnetic field structure is in essence bisymmetric (dynamo mode m = 1) and the magnetic field strength is highest in the ridges of the anomalous arms. The present structure may be the result of compression of a preexisting (not necessarily primordial) bisymmetric field. The KOM expulsion model could give an explanation for this compression.
Anomalous tensoelectric effects in gallium arsenide tunnel diodes
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.
Anomalous flow behavior in nanochannels: A molecular dynamics study
NASA Astrophysics Data System (ADS)
Murad, Sohail; Luo, Lin; Chu, Liang-Yin
2010-06-01
We report molecular dynamics simulations of flow of water in nanochannels with a range of surface wettability characteristics (hydrophobic to strongly hydrophilic) and driving forces (pressures). Our results show apparently anomalous behavior. At low pressures, the rate is higher in nanochannels with hydrophilic surfaces than that with hydrophobic surfaces; however, with high pressure driven flow we observe opposite trends. This apparently anomalous behavior can be explained on the basis of molecular thermodynamics and fluid mechanics considerations. Understanding such behavior is important in many nanofluidic devices such as nanoreactors, nanosensors, and nanochips that are increasingly being designed and used.
Anomalous right coronary artery in a middle-aged patient
Rosseel, Liesbeth; Bonnier, Hans; Sonck, Jeroen
2016-01-01
Abstract Background: An anomalous right coronary artery originating from the left sinus of Valsalva is a rare, but often incidental, finding in middle-aged to elderly people. Prevalence is difficult to define, as well as determining potential harmful hemodynamic consequences. Moreover, the optimal treatment remains debatable. Case summary: The authors present a case of a middle-aged patient diagnosed with an anomalous right coronary artery causing ischemia, who was treated surgically. Conclusion: By reviewing literature, the authors conclude that choice of treatment depends on age, symptoms, and certain anatomic features of this anomaly. However, there are no randomized trials available in this field. PMID:27930539
Regular and anomalous quantum diffusion in the Fibonacci kicked rotator
Casati, G.; Mantica, G.; Shepelyansky, D. L.
2001-06-01
We study the dynamics of a quantum rotator, impulsively kicked according to the almost-periodic Fibonacci sequence. A special numerical technique allows us to carry on this investigation for as many as 10{sup 12} kicks. It is shown that above a critical kick strength, the excitation of the system is well described by regular diffusion, while below this border it becomes anomalous and subdiffusive. A law for the dependence of the exponent of anomalous subdiffusion on the kick strength is established numerically. The analogy between these results and quantum diffusion in models of quasicrystals and in the kicked Harper system is discussed.
Regular and anomalous quantum diffusion in the Fibonacci kicked rotator.
Casati, G; Mantica, G; Shepelyansky, D L
2001-06-01
We study the dynamics of a quantum rotator, impulsively kicked according to the almost-periodic Fibonacci sequence. A special numerical technique allows us to carry on this investigation for as many as 10(12) kicks. It is shown that above a critical kick strength, the excitation of the system is well described by regular diffusion, while below this border it becomes anomalous and subdiffusive. A law for the dependence of the exponent of anomalous subdiffusion on the kick strength is established numerically. The analogy between these results and quantum diffusion in models of quasicrystals and in the kicked Harper system is discussed.
Fluctuation-stabilized marginal networks and anomalous entropic elasticity.
Dennison, M; Sheinman, M; Storm, C; MacKintosh, F C
2013-08-30
We study the elastic properties of thermal networks of Hookean springs. In the purely mechanical limit, such systems are known to have a vanishing rigidity when their connectivity falls below a critical, isostatic value. In this work, we show that thermal networks exhibit a nonzero shear modulus G well below the isostatic point and that this modulus exhibits an anomalous, sublinear dependence on temperature T. At the isostatic point, G increases as the square root of T, while we find G∝Tα below the isostatic point, where α≃0.8. We show that this anomalous T dependence is entropic in origin.
Observation of Anomalous Phonons in Orthorhombic Rare-earth Manganites
P Gao; H Chen; T Tyson; Z Liu; J Bai; L Wang; Y Chio; S Cheong
2011-12-31
We observe the appearance of a phonon near the lock-in temperature in orthorhombic REMnO{sub 3} (RE denotes rare earth) (RE: Lu and Ho) and anomalous phonon hardening in orthorhombic LuMnO{sub 3}. The anomalous phonon occurs at the onset of spontaneous polarization. No such changes were found in incommensurate orthorhombic DyMnO{sub 3}. These observations directly reveal different electric polarization mechanisms in the E-type and incommensurate-type orthorhombic REMnO{sub 3}.
Total Anomalous Pulmonary Venous Connection to the Portal Vein
Wyttenbach, Marina; Carrel, Thierry; Schuepbach, Peter; Tschaeppeler, Heinz; Triller, Juergen
1996-03-15
Anomalous pulmonary venous return represents a rare congenital anomaly with wide anatomic and physiologic variability. We report a case of a newborn with a rare form of total infracardiac anomalous pulmonary venous connection (TAPVC). The pulmonary veins draining both lungs formed two vertical veins, which joined to a common pulmonary trunk below the diaphragm. This venous channel connected to the portal vein through the esophageal hiatus. The diagnosis was suggested by color Doppler sonography and confirmed by intravenous digital subtraction angiography, which allowed definition of the anatomy.
New evidence for geomagnetically trapped anomalous cosmic rays
NASA Technical Reports Server (NTRS)
Cummings, J. R.; Cummings, A. C.; Mewaldt, R. A.; Selesnick, R. S.; Stone, E. C.; Von Rosenvinge, T. T.
1993-01-01
We report new observations of 15 MeV/nuc or greater trapped heavy ions with Z equal to or greater than 2, made on the polar-orbiting SAMPEX spacecraft in late 1992 and early 1993. A trapped population that includes He, N, O, and Ne is found to be located at L = 2. We conclude that the observed N, O, and Ne ions are 'anomalous' cosmic rays, trapped by the mechanism proposed by Blake and Friesen (1977). While it is not expected that this mechanism would also trap anomalous He, the characteristics of the trapped He population are generally consistent with those of N, O, and Ne.
Modified closed chamber sutureless technique for anomalous pulmonary venous connection
Menon, Sabarinath; Mathew, Thomas; Karunakaran, Jayakumar; Dharan, Baiju Sashidhar
2017-01-01
Visibility continues to be a major problem during repair of obstructed total anomalous pulmonary venous connection (TAPVC) resulting in frequent use of deep hypothermia and low flow bypass. Sutureless technique for primary repair of anomalous pulmonary venous connection is fast becoming popular. In this described modification of sutureless technique through the lateral approach, the left atrium is marsupialized around the common pulmonary venous chamber, except on the right lateral aspect, providing a bloodless field with minimal retraction of heart facilitating the surgery at mild hypothermia. This technique can be particularly useful in small confluence obstructed TAPVC and in mixed TAPVC. PMID:28163429
Search for anomalous C-jets in Chacaltaya emulsion chamber experiment
NASA Technical Reports Server (NTRS)
Kumano, H.
1985-01-01
Anomalous C-jets were measured in Chacaltaya emulsion chamber No.17. Measurement of 150 C-jets nuclear interactions occured in the target layer in the chamber itself with total visible energy greater than 5 TeV was completed. they are recorded in area of 11 sq m, corresponding to 17.1 sq m year exposure. Among them, seven events have no pinaught and two events are peculiar in that three showers out of four show abnormal cascade development. Two show remarkable characteristics indicating that they are coming from exotic interactions in the target layer. Illustrations of these events are presented and the thresholds of this type of event are discussed.
Anomalous Transport in the Superfluid Fluctuation Regime
NASA Astrophysics Data System (ADS)
Uchino, Shun; Ueda, Masahito
2017-03-01
Motivated by a recent experiment in ultracold atoms [S. Krinner et al., Proc. Natl. Acad. Sci. U.S.A. 113, 8144 (2016), 10.1073/pnas.1601812113], we analyze transport of attractively interacting fermions through a one-dimensional wire near the superfluid transition. We show that in a ballistic regime where the conductance is quantized in the absence of interaction, the conductance is renormalized by superfluid fluctuations in reservoirs. In particular, the particle conductance is strongly enhanced, and the conductance plateau is blurred by emergent bosonic pair transport. For spin transport, in addition to the contact resistance, the wire itself is resistive, leading to a suppression of the measured spin conductance. Our results are qualitatively consistent with the experimental observations.
Anomalous surface segregation behaviour of some 3d elements in ferromagnetic iron.
Gupta, Michèle; Gupta, Raju P
2013-10-16
The segregation of Cr in Fe is known to be anomalous since the barrier for surface segregation of Cr is not determined by the topmost surface layer, as one would expect, but rather by the subsurface layer where the energy of segregation is much larger and endothermic. This has been attributed to a complex interaction involving the antiferromagnetism of Cr and the ferromagnetism of Fe. We report in this paper the results of our ab initio electronic structure calculations on the segregation behaviour of all the 3d elements on the (1 0 0) surface of ferromagnetic iron in the hope of better understanding this phenomenon. We find a similar behaviour for the segregation of the next antiferromagnetic 3d element Mn in Fe, where the subsurface layer is also found to block the segregation of Mn to the surface. On the other hand, ferromagnetic Co exhibits a normal segregation behaviour. The elements Sc, Cu and Ni do not form solid solutions with ferromagnetic iron. The early elements Ti and V are non-magnetic in their metallic states, but are strongly polarized by Fe, and develop magnetic moments which are aligned antiferromagnetically to those of Fe atoms. While the subsurface layer blocks the segregation of Ti to the surface, no blocking behaviour is found for the segregation of V. The segregation behaviour of all these elements is strongly correlated with the displacement of the solute atoms on the surface of Fe. The elements showing anomalous segregation behaviour are all displaced upwards on the surface, while those showing normal segregation are pulled inwards. These results indicate that the antiferromagnetism of the segregating element plays the key role in the anomalous segregation behaviour in Fe.
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.
Terwilliger, Thomas C.; Bunkóczi, Gábor; Hung, Li-Wei; ...
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, we describe algorithms and tools for evaluating and optimizing the useful anomalous correlation and the anomalous signal in a SAD experiment. 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. Thephenix.plan_sad_experimenttool uses a database of solved and unsolved SAD data sets and the expected characteristics of a SAD data set to estimatemore » 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. Thephenix.scale_and_mergetool 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 thephenix.anomalous_signaltool 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.« less
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, we describe algorithms and tools for evaluating and optimizing the useful anomalous correlation and the anomalous signal in a SAD experiment. A simple theoretical framework [Terwilliger
Terwilliger, Thomas C.; Bunkóczi, Gábor; Hung, Li-Wei; Zwart, Peter H.; Smith, Janet L.; Akey, David L.; Adams, Paul D.
2016-01-01
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. PMID:26960123
Cusp Anomalous Dimension in Maximally Supersymmetric Yang-Mills Theory
NASA Astrophysics Data System (ADS)
Kotanski, J.
2008-12-01
The main features of the cusp anomalous dimension in N=4 supersymmetric Yang-Mills theory are reviewed. Moreover, the strong coupling expansion of the cusp derived in B. Basso, G.P. Korchemsky, J. Kotanski, Phys. Rev. Lett. 100, 091601 (2008) is presented.
Moebius syndrome with total anomalous pulmonary venous connection.
Suvarna, Jyoti; Bagnawar, Mahananda; Deshmukh, C T
2006-05-01
Moebius syndrome is characterized by congenital complete or partial facial nerve palsy with or without paralysis of cranial nerves and often associated with other malformations. Cardiac anomalies though known are very rare and till date only 4 cases have been reported. We present a case of Moebius syndrome with supracardiac total anomalous pulmonary venous connection which has not yet been reported in literature.
Influence of anomalous thermal losses of ignition conditions
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.
The Stark anomalous dispersion optical filter: The theory
NASA Technical Reports Server (NTRS)
Yin, B.; Shay, T. M.
1994-01-01
The Stark anomalous dispersion optical filter is a wide-frequency-tunable ultra-narrow-bandwidth optical filter. The first theoretical investigation of this filter matched to the wavelength of a doubled Nd:YAG laser is reported. The calculations show that such a filter may provide above 80 percent transmission, and a noise equivalent bandwidth of 3 GHz.
Geophysical Characterization and Monitoring for Anomalous Transport (Invited)
NASA Astrophysics Data System (ADS)
Day-Lewis, F. D.; Singha, K.
2013-12-01
For several decades, geophysical methods (e.g., electrical, electromagnetic, and radar) have been used to monitor transport of ionic tracers and contaminants, thus providing information about the spatial and temporal morphology and evolution of tracer or contaminant plumes. In the last five years, time-lapse geophysical methods have been applied to understand non-equilibrium between mobile and immobile (or less mobile) domains in porous media (e.g., fractures and matrix) and surface water (i.e., transient storage). Electrical methods have been used in combination with conventional sampling to investigate the exchange of solute between domains and thereby infer exchange rates and relative volumes of mobile and immobile domains. Other methods, including nuclear magnetic resonance and complex resistivity, have been used to study the distribution of pore sizes present, which in turn control anomalous transport. Here, we (1) review the underlying petrophysical/hydrologic link between anomalous transport and geophysical monitoring; (2) review the emerging body of work using geophysical methods to understand anomalous transport and summarize case studies involving field experiments at an aquifer-storage recovery site in Charleston, SC, and two Department of Energy sites in Hanford, WA and Naturita, CO; and (3) discuss potential future directions for geophysical research to further elucidate anomalous transport behavior.
Anomalous Tropical Ocean Circulation Associated with La Nina Modoki
2011-12-02
Behera , S. A. Rao, H. Weng, and T. Yamagata (2007), El Nifio Modoki and its possible telcconncction, J. Geophys. Res., 112, C11007, doi.10.1029...Oscillation, Geophys. Res. Lett., 24, 779-782, doi:10.1029/97GL00689. Weng, H., S. K. Behera , and T. Yamagata (2009), Anomalous winter cli- mate
Anomalous center of mass shift: gravitational dipole moment.
NASA Astrophysics Data System (ADS)
Jeong, Eue Jin
1997-02-01
The anomalous, energy dependent shift of the center of mass of an idealized, perfectly rigid, uniformly rotating hemispherical shell which is caused by the relativistic mass increase effect is investigated in detail. It is shown that a classical object on impact which has the harmonic binding force between the adjacent constituent particles has the similar effect of the energy dependent, anomalous shift of the center of mass. From these observations, the general mode of the linear acceleration is suggested to be caused by the anomalous center of mass shift whether it's due to classical or relativistic origin. The effect of the energy dependent center of mass shift perpendicular to the plane of rotation of a rotating hemisphere appears as the non zero gravitational dipole moment in general relativity. Controlled experiment for the measurement of the gravitational dipole field and its possible links to the cylindrical type line formation of a worm hole in the extreme case are suggested. The jets from the black hole accretion disc and the observed anomalous red shift from far away galaxies are considered to be the consequences of the two different aspects of the dipole gravity.
Explanation of Two Anomalous Results in Statistical Mediation Analysis
ERIC Educational Resources Information Center
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…
Navigation by anomalous random walks on complex networks
Weng, Tongfeng; Zhang, Jie; Khajehnejad, Moein; Small, Michael; Zheng, Rui; Hui, Pan
2016-01-01
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. PMID:27876855
Anomalous dispersion and the pumping of far infrared (FIR) lasers
NASA Technical Reports Server (NTRS)
Lawandy, N. M.
1978-01-01
It is shown that the anomalous dispersion at the pump transition in molecular far-infrared lasers (FIR) can lead to sizable focusing and defocusing effects. Criteria for beam spreading and trapping are considered with CH2F as an example.
Revisiting the Anomalous rf Field Penetration into a Warm Plasma
Igor D. Kaganovich; Oleg V. Polomarov; Constantine E. Theodosiou
2005-06-24
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.
Fraser syndrome with partial anomalous pulmonary venous connection.
Thapa, Rajoo; Bhattacharya, Arunaloke
2008-06-01
Fraser syndrome is characterized by cryptophthalmos, cutaneous syndactyly, malformations of the larynx and genitourinary tract, craniofacial dysmorphism, orofacial clefting, mental retardation, and musculoskeletal anomalies. We report a case of a two day old neonate who presented with features suggestive of the diagnosis of Fraser syndrome. This child also had partial anomalous pulmonary venous connection and congenital hypo-thyroidism.
Anomalous dc resistivity and double layers in the auroral ionosphere
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.
Theoretical model for a Faraday anomalous dispersion optical filter
NASA Technical Reports Server (NTRS)
Yin, B.; Shay, T. M.
1991-01-01
A model for the Faraday anomalous dispersion optical filter is presented. The model predicts a bandwidth of 0.6 GHz and a transmission peak of 0.98 for a filter operating on the Cs (D2) line. The model includes hyperfine effects and is valid for arbitrary magnetic fields.
Anomalous Diffraction at Ultra-High Energy for Protein Crystallography
Jakoncic,J.; Di Michiel, M.; Zhong, Z.; Honkimaki, V.; Jouanneau, Y.; Stojanoff, V.
2006-01-01
Single-wavelength anomalous diffraction (SAD), multiwavelength anomalous diffraction (MAD) and single isomorphous replacement with anomalous scattering (SIRAS) phasing at ultra-high X-ray energy, 55 keV, are used successfully to determine a high-quality and high-resolution experimental electronic density map of hen egg-white lysozyme, a model protein. Several combinations, between single- and three-wavelength, with native data were exploited to demonstrate that standard phasing procedures with standard equipment and software can successfully be applied to three-dimensional crystal structure determination of a macromolecule, even at these very short wavelengths. For the first time, a high-quality three-dimensional molecular structure is reported from SAD phasing with ultra-high-energy X-rays. The quality of the crystallographic data and the experimental electron density maps meet current standards. The 2.7% anomalous signal from three Ho atoms, at the Ho K edge, was sufficient to obtain a remarkable electron density and build the first lanthanide structure for HEWL in its entirety.
Navigation by anomalous random walks on complex networks
NASA Astrophysics Data System (ADS)
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.
Cosmic ray transport - Modulation and the anomalous component
Evenson, P.; Tuska, E.B. )
1991-01-01
Cosmic ray transport research is reviewed for the 1987-1990 time period, focusing on diffusive transport. Problems discussed include the diffusion model, anomalous components, radial gradient and north south anisotropy, short term modulation, long-term solar modulation, and charge sign dependent modulation. 249 refs.
Erikson, William W.; Coker, Eric N.
2016-11-10
It has long been observed that oxidation processes in metals tend to follow a parabolic rate law associated with the growth of a surface oxide layer. Here we observe that for certain titanium powders, the expected parabolic law (∝t1/2) is recovered, yet for others, the exponent differs significantly. One explanation for this non-parabolic, anomalous diffusion arises from fractal geometry. Theoretical considerations indicate that the time response of diffusion-limited processes in an object closely follow a power-law in time (tn) with n=(E–D)/2, where E is the object's Euclidean dimension and D is its boundary's Hausdorff dimension. Non-integer, (fractal) values of Dmore » will result in n≠1/2. Finite element simulations of several canonical fractal objects were performed to verify the application of this theory; the results matched the theory well. Two different types of titanium powder were tested in isothermal thermogravimetric tests under dilute oxygen. Time-dependent mass uptake data were fit with power-law forms and the associated exponents were used to determine an equivalent fractal dimension. One Ti powder type has an implied surface dimension of ca. 2.3 to 2.5, suggesting fractal geometry may be operative. Finally, the other has a dimension near 2.0, indicating it behaves like traditional material.« less
Macromolecular X-ray structure determination using weak, single-wavelength anomalous data
Bunkóczi, Gábor; McCoy, Airlie J.; Echols, Nathaniel; Grosse-Kunstleve, Ralf W.; Adams, Paul D.; Holton, James M.; Read, Randy J.; Terwilliger, Thomas C.
2014-12-22
We describe a likelihood-based method for determining the substructure of anomalously scattering atoms in macromolecular crystals that allows successful structure determination by single-wavelength anomalous diffraction (SAD) X-ray analysis with weak anomalous signal. With the use of partial models and electron density maps in searches for anomalously scattering atoms, testing of alternative values of parameters and parallelized automated model-building, this method has the potential to extend the applicability of the SAD method in challenging cases.
Anomalous transport in second order hydrodynamics
NASA Astrophysics Data System (ADS)
Megías, Eugenio; Valle, Manuel
2016-11-01
We study the non-dissipative transport effects appearing at second order in the hydrodynamic expansion for a non-interacting gas of chiral fermions by using the partition function formalism. We discuss some features of the corresponding constitutive relations, derive the explicit expressions for the conductivities and compare with existing results in the literature. Talk given by E. Megías at the 4th International Conference on New Frontiers in Physics (ICNFP 2015), 23-30 August 2015, Kolymbari, Crete, Greece.
Evaluation of Anomalous Coronary Arteries from the Pulmonary Artery
Guzeltas, Alper; Ozturk, Erkut; Tanidir, Ibrahim Cansaran; Kasar, Taner; Haydin, Sertac
2017-01-01
Objective This study evaluated clinical and diagnostic findings, treatment methods, and follow-up of cases of anomalous coronary arteries from the pulmonary artery. Methods The study included all cases diagnosed with anomalous coronary arteries from the pulmonary artery between January 2012 and January 2016. Data from patients’ demographic characteristics, electrocardiography, echocardiography, angiographic findings, operation, intensive care unit stay, and follow-up were evaluated. Results The study included 12 patients (8 male, 4 female), 10 with anomalous left coronary artery from the pulmonary artery (ALCAPA) and 2 with anomalous right coronary artery from the pulmonary artery (ARCAPA). Median age at diagnosis was 4 months (range, 1 month - 10 years old) and median weight was 5.5 kg (range, 3-30 kg). The most common complaints were murmur (n=7) and respiratory distress (n=5). In 4 cases, the initial diagnosis was dilated cardiomyopathy. Electrocardiographs were pathologic in all cases. Echocardiographic examination revealed medium to severe mitral valve regurgitation in 4 cases and reduced (< 40%) ejection fraction in 6 patients. Of the 12 patients, 8 underwent direct implantation of the left coronary artery into the aorta, 2 underwent implantation of the right coronary artery into the aorta, and the remaining 2 underwent a Takeuchi procedure. There were no early mortalities. Median hospital stay was 20 days (range, 5-35 days). Median follow-up duration was 18 months (range, 5-36 months), and no cases required further surgery during follow-up. Conclusions Anomalous coronary arteries from the pulmonary artery can be successfully repaired providing there is early diagnosis and effective, appropriate intensive care unit follow-up. Therefore, coronary artery origins should be evaluated carefully, especially in cases with dilated cardiomyopathies.
Magnetic Topological Insulators and Quantum Anomalous Hall Effect
NASA Astrophysics Data System (ADS)
Kou, Xufeng
The engineering of topological surface states is a key to realize applicable devices based on topological insulators (TIs). Among various proposals, introducing magnetic impurities into TIs has been proven to be an effective way to open a surface gap and integrate additional ferromagnetism with the original topological order. In this Dissertation, we study both the intrinsic electrical and magnetic properties of the magnetic TI thin films grown by molecular beam epitaxy. By doping transition element Cr into the host tetradymite-type V-VI semiconductors, we achieve robust ferromagnetic order with a strong perpendicular magnetic anisotropy. With additional top-gating capability, we realize the electric-field-controlled ferromagnetism in the magnetic TI systems, and demonstrate such magneto-electric effects can be effectively manipulated, depending on the interplays between the band topology, magnetic exchange coupling, and structural engineering. Most significantly, we report the observation of quantum anomalous Hall effect (QAHE) in the Cr-doped (BiSb)2Te3 samples where dissipationless chiral edge conduction is realized in the macroscopic millimeter-size devices without the presence of any external magnetic field, and the stability of the quantized Hall conductance of e2/h is well-maintained as the film thickness varies across the 2D hybridization limit. With additional quantum confinement, we discover the metal-to-insulator switching between two opposite QAHE states, and reveal the universal QAHE phase diagram in the thin magnetic TI samples. In addition to the uniform magnetic TIs, we further investigate the TI/Cr-doped TI bilayer structures prepared by the modulation-doped growth method. By controlling the magnetic interaction profile, we observe the Dirac hole-mediated ferromagnetism and develop an effective way to manipulate its strength. Besides, the giant spin-orbit torque in such magnetic TI-based heterostructures enables us to demonstrate the current
Anomalous double-mode RR Lyrae stars in the Magellanic Clouds
NASA Astrophysics Data System (ADS)
Soszyński, I.; Smolec, R.; Dziembowski, W. A.; Udalski, A.; Szymański, M. K.; Wyrzykowski, Ł.; Ulaczyk, K.; Poleski, R.; Pietrukowicz, P.; Kozłowski, S.; Skowron, D.; Skowron, J.; Mróz, P.; Pawlak, M.
2016-12-01
We report the discovery of a new subclass of double-mode RR Lyrae stars in the Large and Small Magellanic Clouds. The sample of 22 pulsating stars has been extracted from the latest edition of the Optical Gravitational Lensing Experiment collection of RR Lyrae variables in the Magellanic System. The stars pulsating simultaneously in the fundamental (F) and first-overtone (1O) modes have distinctly different properties than regular double-mode RR Lyrae variables (RRd stars). The P1O/PF period ratios of our anomalous RRd stars are within a range of 0.725-0.738, while `classical' double-mode RR Lyrae variables have period ratios in the range of 0.742-0.748. In contrast to the typical RRd stars, in the majority of the anomalous pulsators, the F-mode amplitudes are higher than the 1O-mode amplitudes. The light curves associated with the F-mode in the anomalous RRd stars show different morphology than the light curves of, both, regular RRd stars and single-mode RRab stars. Most of the anomalous double-mode stars show long-term modulations of the amplitudes (Blazhko-like effect). Translating the period ratios into the abundance parameter, Z, we find for our stars Z ∈ (0.002, 0.005) - an order of magnitude higher values than typical for RR Lyrae stars. The mass range of the RRd stars inferred from the WI versus PF diagram is (0.55-0.75) M⊙. These parameters cannot be accounted for with single star evolution assuming a Reimers-like mass-loss. Much greater mass-loss caused by interaction with other stars is postulated. We blame the peculiar pulsation properties of our stars to the parametric resonance instability of the 1O-mode to excitation of the F- and 2O-modes as with the inferred parameters of the stars 2ω1O ≈ ωF + ω2O.
Quantum phase transitions and anomalous Hall effect in a pyrochlore Kondo lattice
NASA Astrophysics Data System (ADS)
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.
Charge partitioning and anomalous hole doping in Rh-doped Sr2IrO4
NASA Astrophysics Data System (ADS)
Chikara, S.; Fabbris, G.; Terzic, J.; Cao, G.; Khomskii, D.; Haskel, D.
2017-02-01
The simultaneous presence of sizable spin-orbit interactions and electron correlations in iridium oxides has led to predictions of novel ground states including Dirac semimetals, Kitaev spin liquids, and superconductivity. Electron and hole doping studies of spin-orbit assisted Mott insulator Sr2Ir O4 are being intensively pursued due to extensive parallels with the La2CuO4 parent compound of cuprate superconductors. In particular, the mechanism of charge doping associated with replacement of Ir with Rh ions remains controversial with profound consequences for the interpretation of electronic structure and transport data. Using x-ray absorption near edge structure measurements at the Rh L, K, and Ir L edges we observe anomalous evolution of charge partitioning between Rh and Ir with Rh doping. The partitioning of charge between Rh and Ir sites progresses in a way that holes are initially doped into the Jeff=1 /2 band at low x only to be removed from it at higher x values. This anomalous hole doping naturally explains the reentrant insulating phase in the phase diagram of Sr2Ir1 -xRhxO4 and ought to be considered when searching for superconductivity and other emergent phenomena in iridates doped with 4 d elements.
Charge partitioning and anomalous hole doping in Rh-doped Sr2IrO4
Chikara, S.; Fabbris, G.; Terzic, J.; ...
2017-02-15
The simultaneous presence of sizable spin-orbit interactions and electron correlations in iridium oxides has led to predictions of novel ground states including Dirac semimetals, Kitaev spin liquids, and superconductivity. Electron and hole doping studies of spin-orbit assisted Mott insulator Sr2IrO4 are being intensively pursued due to extensive parallels with the La2CuO4 parent compound of cuprate superconductors. In particular, the mechanism of charge doping associated with replacement of Ir with Rh ions remains controversial with profound consequences for the interpretation of electronic structure and transport data. Using x-ray absorption near edge structure measurements at the Rh L, K, and Ir Lmore » edges we observe anomalous evolution of charge partitioning between Rh and Ir with Rh doping. The partitioning of charge between Rh and Ir sites progresses in a way that holes are initially doped into the Jeff = 1/2 band at low x only to be removed from it at higher x values. Furthermore, this anomalous hole doping naturally explains the reentrant insulating phase in the phase diagram of Sr2Ir1–xRhxO4 and ought to be considered when searching for superconductivity and other emergent phenomena in iridates doped with 4d elements.« less
Anomalous transition in {sup 10}B
Kurath, D.
1995-08-01
The transitions between the J,T = 3,0 ground state of {sup 10}B and the 3,0 state at 4.77 MeV present some puzzling features. The gamma transition between the states is of unknown multipolarity and very weak, with a strength of only 0.1 WU even if it is a pure E2. The shell model with the Cohen-Kurath POT interaction predicts a nearly pure E2 transition but with a transition probability about 4 times too strong. Recent inelastic pion scattering experiments on {sup 10}B excited this state with a strength only one tenth the value predicted by the shell model. It was found that these weak transitions are very sensitive to the wave functions and that orthogonally mixing the states with an intensity of 2% can satisfy both the pion scattering and the {gamma} decay (60% E2, 40% M1).
Can I solve my structure by SAD phasing? Anomalous signal in SAD phasing
Terwilliger, Thomas C.; Bunkóczi, Gábor; Hung, Li-Wei; ...
2016-03-01
A key challenge in the SAD phasing method is solving a structure when the anomalous signal-to-noise ratio is low. We present a simple theoretical framework for describing measurements of anomalous differences and the resulting useful anomalous correlation and anomalous signal in a SAD experiment. 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.more » 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. In conclusion, 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.« less
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. We present a simple theoretical framework for describing measurements of anomalous differences and the resulting useful anomalous correlation and anomalous signal in a SAD experiment. 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. In conclusion, 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.
Optical Detection of Anomalous Nitrogen in Comets
NASA Astrophysics Data System (ADS)
2003-12-01
. Introducing instead the terrestrial ratio for nitrogen-15 (1/272) significantly degrades the fit and thus that ratio can clearly be ruled out in Comet LINEAR. At the time of the VLT observations, the comet was of 9th magnitude, i.e. about 15 times fainter than what can be perceived with the unaided eye. The distance from the Sun was about 180 million km; the distance from the Earth was 186 million km. The observations included calibration spectra of sunlight reflected from the lunar surface; they were used to "subtract" the solar signatures in the comet's spectrum, caused by reflection of sunlight from the dust particles around the comet. As expected, in addition to emission from "normal" CN-molecules ( 12 C 14 N), the UVES data also show emission lines of the 13 C 14 N-molecule that contains the rare isotope carbon-13. The derived 12 C/ 13 C isotopic ratio is 115 ± 20, quite similar to the "standard" solar system value of 89. However, there is also a series of weak features that are positioned exactly at the theoretical wavelengths of emission lines from 12 C 15 N-molecules, cf. PR Photo 28c/03 . The excellent fit that is evident in this diagram proves beyond any doubt the presence of nitrogen-15 in Comet LINEAR and allows a quite accurate determination of the isotopic ratio. The "anomalous" nitrogen isotope ratio in comets In 1997, the same group of astronomers obtained spectra of the (at that time) much brighter Comet Hale-Bopp with the 2.6-m NOT telescope (Roque de los Muchachos Observatory, La Palma, Canary Islands, Spain) in order to investigate the isotopic ratio of carbon-12 to carbon-13. Claude Arpigny remembers: " Interestingly, our spectra of Hale-Bopp showed a number of weak and unidentified emission lines. We later realised that they were positioned close to the theoretical wavelengths of some lines from the 12 C 15 N-molecule. This was a pleasant surprise, as lines from that molecular species were previously believed to be so faint that they would not be
Phonons of the anomalous element cerium
Krisch, Michael; Farber, D. L.; Xu, R.; Antonangeli, Daniele; Aracne, C. M.; Beraud, Alexandre; Chiang, Tai-Chang; Zarestky, J.; Kim, Duck Young; Isaev, Eyvaz I.; Ahuja, Rajeev; Johansson, Börje
2011-01-01
Many physical and chemical properties of the light rare-earths and actinides are governed by the active role of f electrons, and despite intensive efforts the details of the mechanisms of phase stability and transformation are not fully understood. A prominent example which has attracted a lot of interest, both experimentally and theoretically over the years is the isostructural γ - α transition in cerium. We have determined by inelastic X-ray scattering, the complete phonon dispersion scheme of elemental cerium across the γ → α transition, and compared it with theoretical results using ab initio lattice dynamics. Several phonon branches show strong changes in the dispersion shape, indicating large modifications in the interactions between phonons and conduction electrons. This is reflected as well by the lattice Grüneisen parameters, particularly around the X point. We derive a vibrational entropy change , illustrating the importance of the lattice contribution to the transition. Additionally, we compare first principles calculations with the experiments to shed light on the mechanism underlying the isostructural volume collapse in cerium under pressure. PMID:21597000
Anomalous dimensions and non-gaussianity
Green, Daniel; Lewandowski, Matthew; Senatore, Leonardo; Silverstein, Eva; Zaldarriaga, Matias
2013-10-01
We analyze the signatures of inflationary models that are coupled to interacting field theories, a basic class of multifield models also motivated by their role in providing dynamically small scales. Near the squeezed limit of the bispectrum, we find a simple scaling behavior determined by operator dimensions, which are constrained by the appropriate unitarity bounds. Specifically, we analyze two simple and calculable classes of examples: conformal field theories (CFTs), and large-N CFTs deformed by relevant time-dependent double-trace operators. Together these two classes of examples exhibit a wide range of scalings and shapes of the bispectrum, including nearly equilateral, orthogonal and local non-Gaussianity in different regimes. Along the way, we compare and contrast the shape and amplitude with previous results on weakly coupled fields coupled to inflation. This signature provides a precision test for strongly coupled sectors coupled to inflation via irrelevant operators suppressed by a high mass scale up to ~ 103 times the inflationary Hubble scale.
Search for anomalous WW and WZ production at D0
Abachi, S.
1995-07-01
We present a preliminary result from a search for anomalous WW and WZ production in p{bar p} collisions at {radical}s = 1.8 TeV using p{bar p} {yields} e{nu}jj events observed during the 1992-1993 run of the Fermilab Tevatron collider. A fit to the p{sub T} spectrum of W(e{nu}) yields direct limits on the CP-conserving anomalous WW{gamma} and WWZ coupling parameters of -0.89 < {Delta}{kappa} < 1.07 ({lambda} = 0) and -0.66 < {lambda} < 0.67 ({Delta}{kappa} = 0) at the 95% confidence level, assuming that the WWZ coupling parameters are equal to the WW{gamma} coupling parameters, and a form factor scale {Lambda} = 1.5 TeV.
Time-average based on scaling law in anomalous diffusions
NASA Astrophysics Data System (ADS)
Kim, Hyun-Joo
2015-05-01
To solve the obscureness in measurement brought about from the weak ergodicity breaking appeared in anomalous diffusions, we have suggested the time-averaged mean squared displacement (MSD) /line{δ 2 (τ )}τ with an integral interval depending linearly on the lag time τ. For the continuous time random walk describing a subdiffusive behavior, we have found that /line{δ 2 (τ )}τ ˜ τ γ like that of the ensemble-averaged MSD, which makes it be possible to measure the proper exponent values through time-average in experiments like a single molecule tracking. Also, we have found that it has originated from the scaling nature of the MSD at an aging time in anomalous diffusion and confirmed them through numerical results of the other microscopic non-Markovian model showing subdiffusions and superdiffusions with the origin of memory enhancement.
Causes of anomalous line-splitting in RV Tauri stars
NASA Astrophysics Data System (ADS)
Baird, S. R.
1984-01-01
Data on the anomalous absorption-line splitting and emission in the RV Tauri stars AC Her, U Mon, and R Sct are examined. It is shown that the Karp line-splitting mechanism for cepheids cannot explain the highly redshifted lines that appear without antecedents in some RV Tauri stars and that the veiling that occurs during rising light appears to affect the bluer absorption components more than the high redshift ones. Evidence is reviewed showing strong shock waves must be present in RV Tauri star atmospheres, and a two-shock picture to explain the anomalous line splitting is presented based on a model for long-period variables by Hill and Willson. Advantages and difficulties of the model are discussed.
A fractional calculus model of anomalous dispersion of acoustic waves.
Wharmby, Andrew W
2016-09-01
An empirical formula based on viscoelastic analysis techniques that employs concepts from the fractional calculus that was used to model the dielectric behavior of materials exposed to oscillating electromagnetic fields in the radiofrequency, terahertz, and infrared bands. This work adapts and applies the formula to model viscoelastic behavior of materials that show an apparent increase of phase velocity of vibration with an increase in frequency, otherwise known as anomalous dispersion. A fractional order wave equation is derived through the application of the classic elastic-viscoelastic correspondence principle whose analytical solution is used to describe absorption and dispersion of acoustic waves in the viscoelastic material displaying anomalous dispersion in a specific frequency range. A brief discussion and comparison of an alternative fractional order wave equation recently formulated is also included.
Fast plasma heating by anomalous and inertial resistivity effects
NASA Technical Reports Server (NTRS)
Duijveman, A.; Hoyng, P.; Ionson, J. A.
1981-01-01
Fast plasma heating by anomalous and inertial resistivity effects is described. A small fraction of the plasma contains strong currents that run parallel to the magnetic field and are driven by an exponentiating electric field. The anomalous character of the current dissipation is caused by the excitation of electrostatic ion cyclotron and/or ion acoustic waves. The role of resistivity due to geometrical effects is considered. Through the use of a marginal stability analysis, equations for the average electron and ion temperatures are derived and numerically solved. The evolution of the plasma is described as a path in the drift velocity diagram, in which the drift velocity is plotted as a function of the electron to ion temperature ratio.
Anomalous Brownian motion and viscoelasticity of the ear's mechanoelectrical transducer
NASA Astrophysics Data System (ADS)
Andor-Ardó, Daniel; Kozlov, Andrei; Hudspeth, A. J.
2009-03-01
The Brownian motion of a particle in a complex environment is known to display anomalous power-law scaling in which the mean squared displacement is proportional to a fractional power of time. Using laser interferometry and analytical methods of microrheology, we examine nanometer-scale thermal motions of hair bundles in the internal ear and show that these cellular organelles undergo fractional Brownian motion. This anomalous scaling is caused by viscoelasticity of the gating springs, elements that transmit energy in a sound to the mechanosensitive ion channels. These results demonstrate a connection between rheology and auditory physiology, and indicate that statistical properties of the thermal noise in the ear can be determined by dynamics of a small number of key molecules.
Probabilistic phase space trajectory description for anomalous polymer dynamics.
Panja, Debabrata
2011-03-16
It has been recently shown that the phase space trajectories for the anomalous dynamics of a tagged monomer of a polymer--for single polymeric systems and phenomena such as phantom Rouse, self-avoiding Rouse, and Zimm ones, reptation, and translocation through a narrow pore in a membrane, as well as for many polymeric systems such as polymer melts in the entangled regime--are robustly described by the generalized Langevin equation. Here I show that the probability distribution of phase space trajectories for all of these classical anomalous dynamics for single polymers is that of a fractional Brownian motion (fBm), while the dynamics for polymer melts between the entangled regime and the eventual diffusive regime exhibits small but systematic deviations from that of a fBm.
Anomalous postcritical refraction behavior for certain transversely isotropic media
Fa, L.; Brown, R.L.; Castagna, J.P.
2006-01-01
Snell's law at the boundary between two transversely isotropic media with a vertical axis of symmetry (VTI media) can be solved by setting up a fourth order polynomial for the sine of the reflection/transmission angles. This approach reveals the possible presence of an anomalous postcritical angle for certain transversely isotropic media. There are thus possibly three incident angle regimes for the reflection/refraction of longitudinal or transverse waves incident upon a VTI medium: precritical, postcritical/preanomalous, and postanomalous. The anomalous angle occurs for certain strongly anisotropic media where the required root to the phase velocity equation must be switched in order to obey Snell's law. The reflection/transmission coefficients, polarization directions, and the phase velocity are all affected by both the anisotropy and the incident angle. The incident critical angles are also effected by the anisotropy. ?? 2006 Acoustical Society of America.
The discovery of an anomalous RGB in M 2.
NASA Astrophysics Data System (ADS)
Lardo, C.; Pancino, E.; Mucciarelli, A.; Milone, A. P.
Using UV images taken with the Telescopio Nazionale Galileo, we discovered an anomalous sequence in the color-magnitude diagram of M 2. This feature appears as a narrow poor-populated red giant branch, which extends down to the sub giant branch region. We speculate that this new feature could be the extension of the faint component of the split sub giant branch recently discovered by Piotto et al. We identified in our U,V images two CH stars detected in previous studies. These stars, which are both cluster members, fall on this redder sequence, suggesting indeed that the anomalous RGB should have a peculiar chemical pattern. Unfortunately, no additional spectra were obtained for stars in this previously unknown substructure.
Anomalous Transport of High Energy Cosmic Rays in Galactic Superbubbles
NASA Technical Reports Server (NTRS)
Barghouty, Nasser F.
2014-01-01
High-energy cosmic rays may exhibit anomalous transport as they traverse and are accelerated by a collection of supernovae explosions in a galactic superbubble. Signatures of this anomalous transport can show up in the particles' evolution and their spectra. In a continuous-time-random- walk (CTRW) model assuming standard diffusive shock acceleration theory (DSA) for each shock encounter, and where the superbubble (an OB stars association) is idealized as a heterogeneous region of particle sources and sinks, acceleration and transport in the superbubble can be shown to be sub-diffusive. While the sub-diffusive transport can be attributed to the stochastic nature of the acceleration time according to DSA theory, the spectral break appears to be an artifact of transport in a finite medium. These CTRW simulations point to a new and intriguing phenomenon associated with the statistical nature of collective acceleration of high energy cosmic rays in galactic superbubbles.
Normal and anomalous diffusion of Brownian particles on disordered potentials
NASA Astrophysics Data System (ADS)
Salgado-García, R.
2016-07-01
In this work we study the transition from normal to anomalous diffusion of Brownian particles on disordered potentials. The potential model consists of a series of "potential hills" (defined on a unit cell of constant length) whose heights are chosen randomly from a given distribution. We calculate the exact expression for the diffusion coefficient in the case of uncorrelated potentials for arbitrary distributions. We show that when the potential heights have a Gaussian distribution (with zero mean and a finite variance) the diffusion of the particles is always normal. In contrast, when the distribution of the potential heights is exponentially distributed the diffusion coefficient vanishes when the system is placed below a critical temperature. We calculate analytically the diffusion exponent for the anomalous (subdiffusive) phase by using the so-called "random trap model". Our predictions are tested by means of Langevin simulations obtaining good agreement within the accuracy of our numerical calculations.
Anomalous invasion in a 2d model of chemotactic predation
NASA Astrophysics Data System (ADS)
Willemsen, Jorge F.
2010-09-01
It has been hypothesized that plankton predators sense the presence of their prey through detection of chemical signals exuded by the prey. This process is formulated using elements of existing models, tailored to correspond to the specific process under investigation. The motivation for the resulting model is discussed in detail. Numerical results are then presented. It is found that the front representing the advance of the predator into the prey is irregular in a novel way, and the reasons for this anomalous invasion are discussed. It is recognized that reaction-diffusion models, starting perhaps with Turing, can lead to what might have been thought of as anomalous patterns - yet the “flicker” front advance discovered here is indeed novel.
Anomalous postcritical refraction behavior for certain transversely isotropic media.
Fa, Lin; Brown, Ray L; Castagna, John P
2006-12-01
Snell's law at the boundary between two transversely isotropic media with a vertical axis of symmetry (VTI media) can be solved by setting up a fourth order polynomial for the sine of the reflection/transmission angles. This approach reveals the possible presence of an anomalous postcritical angle for certain transversely isotropic media. There are thus possibly three incident angle regimes for the reflection/refraction of longitudinal or transverse waves incident upon a VTI medium: precritical, postcritical/preanomalous, and postanomalous. The anomalous angle occurs for certain strongly anisotropic media where the required root to the phase velocity equation must be switched in order to obey Snell's law. The reflection/transmission coefficients, polarization directions, and the phase velocity are all affected by both the anisotropy and the incident angle. The incident critical angles are also effected by the anisotropy.
Anomalous refraction of guided waves via embedded acoustic metasurfaces
NASA Astrophysics Data System (ADS)
Zhu, Hongfei; Semperlotti, Fabio
2016-04-01
We illustrate the design of acoustic metasurfaces based on geometric tapers and embedded in thin-plate structures. The metasurface is an engineered discontinuity that enables anomalous refraction of guided wave modes according to the Generalized Snell's Law. Locally-resonant geometric torus-like tapers are designed in order to achieve metasurfaces having discrete phase-shift profiles that enable a high level of control of refraction of the wavefronts. Results of numerical simulations show that anomalous refraction can be achieved on transmitted anti-symmetric modes (A0) either when using a symmetric (S0) or anti-symmetric (A0) incident wave, where the former case clearly involves mode conversion mechanisms.
Multiwavelength anomalous diffraction at high x-ray intensity.
Son, Sang-Kil; Chapman, Henry N; Santra, Robin
2011-11-18
The multiwavelength anomalous diffraction (MAD) method is used to determine phase information in x-ray crystallography by employing anomalous scattering from heavy atoms. X-ray free-electron lasers (FELs) show promise for revealing the structure of single molecules or nanocrystals, but the phase problem remains largely unsolved. Because of the ultrabrightness of x-ray FEL, samples experience severe electronic radiation damage, especially to heavy atoms, which hinders direct implementation of MAD with x-ray FELs. Here, we propose a generalized version of MAD phasing at high x-ray intensity. We demonstrate the existence of a Karle-Hendrickson-type equation in the high-intensity regime and calculate relevant coefficients with detailed electronic damage dynamics of heavy atoms. The present method offers a potential for ab initio structural determination in femtosecond x-ray nanocrystallography.
Anomalous sounds from the entry of meteor fireballs.
Keay, C S
1980-10-03
A very bright fireball observed over New South Wales in 1978 produced anomalous sounds clearly audible to some of the observers. An investigation of the phenomenon indicates that bright fireballs radiate considerable electromagnetic energy in the very-low-frequency (VLF) region of the spectrum. A mechanism for the production of VLF emissions from the highly energetic wake turbulence of the fireball is proposed. Trials with human subjects revealed a very extended range of thresholds for the perception of electrically excited sounds among a sample population, particularly when the VLF electric field excites surface acoustic waves in surrounding objects. This fact, together with variable propagation effects and local conditions, can account for the sporadic distribution of reports of anomalous sounds from fireballs and auroras.
Hussein, Khalid
2012-02-01
Citation Information: Originator: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Publication Date: 2012 Title: Very Warm Modeled Temperature Dolores Edition: First Note: This “Weakly Anomalous to Anomalous Surface Temperature” dataset differs from the “Anomalous Surface Temperature” dataset for this county (another remotely sensed CIRES product) by showing areas of modeled temperatures between 1σ and 2σ above the mean, as opposed to the greater than 2σ temperatures contained in the “Anomalous Surface Temperature” dataset. Publication Information: Publication Place: Earth Science & Observation Center, Cooperative Institute for Research in Environmental Science (CIRES), University of Colorado, Boulder Publisher: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Description: This layer contains areas of anomalous surface temperature in Dolores County identified from ASTER thermal data and spatial based insolation model. The temperature is calculated using the Emissivity Normalization Algorithm that separate temperature from emissivity. The incoming solar radiation was calculated using spatial based insolation model developed by Fu and Rich (1999). Then the temperature due to solar radiation was calculated using emissivity derived from ASTER data. The residual temperature, i.e. temperature due to solar radiation subtracted from ASTER temperature was used to identify thermally anomalous areas. Areas that had temperature greater than 2σ were considered ASTER modeled very warm surface exposures (thermal anomalies) Spatial Domain: Extent: Top: 4186234.213315 m Left: 212558.673056 m Right: 232922.811862 m Bottom: 4176781.467043 m Contact Information: Contact Organization: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Contact Person: Khalid Hussein Address: CIRES, Ekeley Building Earth Science & Observation Center (ESOC) 216 UCB City: Boulder State: CO
Hussein, Khalid
2012-02-01
Citation Information: Originator: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Publication Date: 2012 Title: Warm Modeled Temperature Garfield Edition: First Note: This “Weakly Anomalous to Anomalous Surface Temperature” dataset differs from the “Anomalous Surface Temperature” dataset for this county (another remotely sensed CIRES product) by showing areas of modeled temperatures between 1σ and 2σ above the mean, as opposed to the greater than 2σ temperatures contained in the “Anomalous Surface Temperature” dataset. Publication Information: Publication Place: Earth Science & Observation Center, Cooperative Institute for Research in Environmental Science (CIRES), University of Colorado, Boulder Publisher: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Description: This layer contains areas of anomalous surface temperature in Garfield County identified from ASTER thermal data and spatial based insolation model. The temperature is calculated using the Emissivity Normalization Algorithm that separate temperature from emissivity. The incoming solar radiation was calculated using spatial based insolation model developed by Fu and Rich (1999). Then the temperature due to solar radiation was calculated using emissivity derived from ASTER data. The residual temperature, i.e. temperature due to solar radiation subtracted from ASTER temperature was used to identify thermally anomalous areas. Areas that had temperature between 1σ and 2σ were considered ASTER modeled warm surface exposures (thermal anomalies) Spatial Domain: Extent: Top: 4442180.552290 m Left: 268655.053363 m Right: 359915.053363 m Bottom: 4312490.552290 m Contact Information: Contact Organization: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Contact Person: Khalid Hussein Address: CIRES, Ekeley Building Earth Science & Observation Center (ESOC) 216 UCB City: Boulder State: CO Postal
Hussein, Khalid
2012-02-01
Citation Information: Originator: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Publication Date: 2012 Title: Very Warm Modeled Temperature Chaffee Edition: First Note: This “Weakly Anomalous to Anomalous Surface Temperature” dataset differs from the “Anomalous Surface Temperature” dataset for this county (another remotely sensed CIRES product) by showing areas of modeled temperatures between 1σ and 2σ above the mean, as opposed to the greater than 2σ temperatures contained in the “Anomalous Surface Temperature” dataset. Publication Information: Publication Place: Earth Science & Observation Center, Cooperative Institute for Research in Environmental Science (CIRES), University of Colorado, Boulder Publisher: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Description: This layer contains areas of anomalous surface temperature in Chaffee County identified from ASTER thermal data and spatial based insolation model. The temperature is calculated using the Emissivity Normalization Algorithm that separate temperature from emissivity. The incoming solar radiation was calculated using spatial based insolation model developed by Fu and Rich (1999). Then the temperature due to solar radiation was calculated using emissivity derived from ASTER data. The residual temperature, i.e. temperature due to solar radiation subtracted from ASTER temperature was used to identify thermally anomalous areas. Areas that had temperature greater than 2σ were considered ASTER modeled very warm surface exposures (thermal anomalies) Spatial Domain: Extent: Top: 4333432.368072 m Left: 366907.700763 m Right: 452457.816015 m Bottom: 4208271.566715 m Contact Information: Contact Organization: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Contact Person: Khalid Hussein Address: CIRES, Ekeley Building Earth Science & Observation Center (ESOC) 216 UCB City: Boulder State: CO
Hussein, Khalid
2012-02-01
Citation Information: Originator: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Publication Date: 2012 Title: Very Warm Modeled Temperature Alamosa Saguache Edition: First Note: This “Weakly Anomalous to Anomalous Surface Temperature” dataset differs from the “Anomalous Surface Temperature” dataset for this county (another remotely sensed CIRES product) by showing areas of modeled temperatures between 1σ and 2σ above the mean, as opposed to the greater than 2σ temperatures contained in the “Anomalous Surface Temperature” dataset. Publication Information: Publication Place: Earth Science & Observation Center, Cooperative Institute for Research in Environmental Science (CIRES), University of Colorado, Boulder Publisher: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Description: This layer contains areas of anomalous surface temperature in Alamosa and Saguache Counties identified from ASTER thermal data and spatial based insolation model. The temperature is calculated using the Emissivity Normalization Algorithm that separate temperature from emissivity. The incoming solar radiation was calculated using spatial based insolation model developed by Fu and Rich (1999). Then the temperature due to solar radiation was calculated using emissivity derived from ASTER data. The residual temperature, i.e. temperature due to solar radiation subtracted from ASTER temperature was used to identify thermally anomalous areas. Areas that had temperature greater than 2σ were considered ASTER modeled very warm surface exposures (thermal anomalies) Spatial Domain: Extent: Top: 4217727.601630 m Left: 394390.400264 m Right: 460179.841813 m Bottom: 4156258.036086 m Contact Information: Contact Organization: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Contact Person: Khalid Hussein Address: CIRES, Ekeley Building Earth Science & Observation Center (ESOC) 216 UCB
Hussein, Khalid
2012-02-01
Citation Information: Originator: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Publication Date: 2012 Title: Warm Modeled Temperature Archuleta Note: This “Weakly Anomalous to Anomalous Surface Temperature” dataset differs from the “Anomalous Surface Temperature” dataset for this county (another remotely sensed CIRES product) by showing areas of modeled temperatures between 1σ and 2σ above the mean, as opposed to the greater than 2σ temperatures contained in the “Anomalous Surface Temperature” dataset. Edition: First Publication Information: Publication Place: Earth Science & Observation Center, Cooperative Institute for Research in Environmental Science (CIRES), University of Colorado, Boulder Publisher: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Description: This layer contains areas of anomalous surface temperature in Archuleta County identified from ASTER thermal data and spatial based insolation model. The temperature is calculated using the Emissivity Normalization Algorithm that separate temperature from emissivity. The incoming solar radiation was calculated using spatial based insolation model developed by Fu and Rich (1999). Then the temperature due to solar radiation was calculated using emissivity derived from ASTER data. The residual temperature, i.e. temperature due to solar radiation subtracted from ASTER temperature was used to identify thermally anomalous areas. Areas that had temperature between 1σ and 2σ were considered ASTER modeled warm surface exposures (thermal anomalies). Spatial Domain: Extent: Top: 4144825.235807 m Left: 285446.256851 m Right: 350577.338852 m Bottom: 4096962.250137 m Contact Information: Contact Organization: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Contact Person: Khalid Hussein Address: CIRES, Ekeley Building Earth Science & Observation Center (ESOC) 216 UCB City: Boulder State: CO
Hussein, Khalid
2012-02-01
Citation Information: Originator: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Publication Date: 2012 Title: Warm Modeled Temperature Routt Edition: First Note: This “Weakly Anomalous to Anomalous Surface Temperature” dataset differs from the “Anomalous Surface Temperature” dataset for this county (another remotely sensed CIRES product) by showing areas of modeled temperatures between 1σ and 2σ above the mean, as opposed to the greater than 2σ temperatures contained in the “Anomalous Surface Temperature” dataset. Publication Information: Publication Place: Earth Science & Observation Center, Cooperative Institute for Research in Environmental Science (CIRES), University of Colorado, Boulder Publisher: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Description: This layer contains areas of anomalous surface temperature in Routt County identified from ASTER thermal data and spatial based insolation model. The temperature is calculated using the Emissivity Normalization Algorithm that separate temperature from emissivity. The incoming solar radiation was calculated using spatial based insolation model developed by Fu and Rich (1999). Then the temperature due to solar radiation was calculated using emissivity derived from ASTER data. The residual temperature, i.e. temperature due to solar radiation subtracted from ASTER temperature was used to identify thermally anomalous areas. Areas that had temperature between 1σ and 2σ were considered ASTER modeled warm surface exposures (thermal anomalies) Spatial Domain: Extent: Top: 4501071.574000 m Left: 311351.975000 m Right: 359411.975000 m Bottom: 4447521.574000 m Contact Information: Contact Organization: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Contact Person: Khalid Hussein Address: CIRES, Ekeley Building Earth Science & Observation Center (ESOC) 216 UCB City: Boulder State: CO Postal Code
Anomalous transport in the crowded world of biological cells.
Höfling, Felix; Franosch, Thomas
2013-04-01
A ubiquitous observation in cell biology is that the diffusive motion of macromolecules and organelles is anomalous, and a description simply based on the conventional diffusion equation with diffusion constants measured in dilute solution fails. This is commonly attributed to macromolecular crowding in the interior of cells and in cellular membranes, summarizing their densely packed and heterogeneous structures. The most familiar phenomenon is a sublinear, power-law increase of the mean-square displacement (MSD) as a function of the lag time, but there are other manifestations like strongly reduced and time-dependent diffusion coefficients, persistent correlations in time, non-Gaussian distributions of spatial displacements, heterogeneous diffusion and a fraction of immobile particles. After a general introduction to the statistical description of slow, anomalous transport, we summarize some widely used theoretical models: Gaussian models like fractional Brownian motion and Langevin equations for visco-elastic media, the continuous-time random walk model, and the Lorentz model describing obstructed transport in a heterogeneous environment. Particular emphasis is put on the spatio-temporal properties of the transport in terms of two-point correlation functions, dynamic scaling behaviour, and how the models are distinguished by their propagators even if the MSDs are identical. Then, we review the theory underlying commonly applied experimental techniques in the presence of anomalous transport like single-particle tracking, fluorescence correlation spectroscopy (FCS) and fluorescence recovery after photobleaching (FRAP). We report on the large body of recent experimental evidence for anomalous transport in crowded biological media: in cyto- and nucleoplasm as well as in cellular membranes, complemented by in vitro experiments where a variety of model systems mimic physiological crowding conditions. Finally, computer simulations are discussed which play an important
Compensation for red-green contrast loss in anomalous trichromats
Boehm, A. E.; MacLeod, D. I. A.; Bosten, J. M.
2014-01-01
For anomalous trichromats, threshold contrasts for color differences captured by the L and M cones and their anomalous analogs are much higher than for normal trichromats. The greater spectral overlap of the cone sensitivities reduces chromatic contrast both at and above threshold. But above threshold, adaptively nonlinear processing might compensate for the chromatically impoverished photoreceptor inputs. Ratios of sensitivity for threshold variations and for color appearance along the two cardinal axes of MacLeod-Boynton chromaticity space were calculated for three groups: normals (N = 15), deuteranomals (N = 9), and protanomals (N = 5). Using a four-alternative forced choice (4AFC) task, threshold sensitivity was measured in four color-directions along the two cardinal axes. For the same participants, we reconstructed perceptual color spaces for the positions of 25 hues using multidimensional scaling (MDS). From the reconstructed color spaces we extracted “color difference ratios,” defined as ratios for the size of perceived color differences along the L/(L + M) axis relative to those along the S/(L + M) axis, analogous to “sensitivity ratios” extracted from the 4AFC task. In the 4AFC task, sensitivity ratios were 38% of normal for deuteranomals and 19% of normal for protanomals. Yet, in the MDS results, color difference ratios were 86% of normal for deuteranomals and 67% of normal for protanomals. Thus, the contraction along the L/(L + M) axis shown in the perceptual color spaces of anomalous trichromats is far smaller than predicted by their reduced sensitivity, suggesting that an adaptive adjustment of postreceptoral gain may magnify the cone signals of anomalous trichromats to exploit the range of available postreceptoral neural signals. PMID:25413625
Anomalous atmospheric absorption spectra due to water dimer
NASA Astrophysics Data System (ADS)
Cai, Peipei; Zhang, Hansheng; Shen, Shanxiong; Cheng, I.-Shan
1986-11-01
The anomalous atmospheric absorption spectra in the window wavelength region of 8-14 microns have been suggested due to the water dimer. Based on laboratory measurements, water continuum CO2 laser absorption spectra and a resonance absorption line due to the weak local wave vapor pure rotational transition have been reported. The equilibrium concentration of water dimers in the atmosphere, the electronic binding energy and the theoretical calculations for absorption attenuation have been obtained in agreement with published data.
Decoupling and anomalous bandcrossings in odd-proton nuclei
Wu, C.S. , Center of Theoretical Physics, P.O. Box 8730, Beijing 100080 Department of Physics, Peking University, Beijing 100871 Institute of Theoretical Physics, Academia Sinica, Beijing 100080 )
1995-04-01
The anomalous bandcrossing observed in the [541] [down arrow] bands of odd-[ital Z] nuclei from the rare-earth region was investigated in the framework of the particle-rotor model. The participation of the decoupling term in the [ital K]=1/2 band will give rise to a significant shift of the bandcrossing frequency, with an amplitude comparable to the observed values.
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.
Identification of anomalous motion of thunderstorms using daily rainfall fields
NASA Astrophysics Data System (ADS)
del Moral, Anna; Llasat, Maria Carmen; Rigo, Tomeu
2016-04-01
Adverse weather phenomena in Catalonia (NE of the Iberian Peninsula) is commonly associated to heavy rains, large hail, strong winds, and/or tornados, all of them caused by thunderstorms. In most of the cases with adverse weather, thunderstorms vary sharply their trajectories in a concrete moment, changing completely the motion directions that have previously followed. Furthermore, it is possible that a breaking into several cells may be produced, or, in the opposite, it can be observed a joining of different thunderstorms into a bigger system. In order to identify the main features of the developing process of thunderstorms and the anomalous motions that these may follow in some cases, this contribution presents a classification of the events using daily rainfall fields, with the purpose of distinguishing quickly anomalous motion of thunderstorms. The methodology implemented allows classifying the daily rainfall fields in three categories by applying some thresholds related with the daily precipitation accumulated values and their extension: days with "no rain", days with "potentially convective" rain and days with "non-potentially convective" rain. Finally, for those "potentially convective" daily rainfall charts, it also allows a geometrical identification and classification of all the convective structures into "ellipse" and "non-ellipse", obtaining then the structures with "normal" or "anomalous" motion pattern, respectively. The work is focused on the period 2008-2015, and presents some characteristics of the rainfall behaviour in terms of the seasonal distribution of convective rainfall or the geographic variability. It shows that convective structures are mainly found during late spring and summer, even though they can be recorded in any time of the year. Consequently, the maximum number of convective structures with anomalous motion is recorded between July and November. Furthermore, the contribution shows the role of the orography of Catalonia in the
Anomalous Reflectivity Losses of Coated Mirrors Used in the Infrared,
1982-01-01
Fig 1 and Fig 2. Experi- mental observations of anomalous reflectivity losses are discussed in the next 1 paragraph. From Table 1 and the experimental... observations it can be seen that the losses occur for only one direction of polarisation Rp, and are not found at normal incidence. Also that the...protected aluminium (measured for us by SIRA institute (3 )) is illustrated in Fig 2 for comparison with the spectra calculated for Al + SiO and Al + SiO 2
Anomalous systemic arterial supply of pulmonary sequestration in adult patients
Hou, Xiaomeng; Li, Ji; Li, Jing; Cai, Baiqiang
2017-01-01
OBJECTIVES: This study described the characteristics of the systemic arterial supply of pulmonary sequestration (PS) in an attempt to better distinguish PS from other acquired lesions. METHODS: We identified 25 patients hospitalized at the Peking Union Medical College Hospital during January 2013 to December 2015 with the assistance of medical catalogers. Twenty-three patients with a definite diagnosis of “pulmonary sequestration” clinically or pathologically were included in the study. The medical records, imaging information, and pathological data were reviewed retrospectively. The general characteristics of the patients and the features of the anomalous arteries were summarized. RESULTS: Aberrant arterial supply of PS was found in all 23 (100%) cases. Among them, twenty patients received surgery, including 14 (70%) with aberrant arterial supply found before surgery, and the other 6 (30%) found during surgery. Nineteen (82.6%) patients had a single systematic arterial supply, with a median diameter of 8 mm. More than one arterial supplies were found in four (17.4%) cases. In 21 (91.3%) cases, the anomalous systemic artery originated from the descending thoracic aorta just adjacent to the sequestrated lung which it supplied, without the presence of accompanying bronchi. In twenty (87.0%) patients who received the surgical intervention, samples of 12 (85.7%) were proved to have elastic vessel walls, out of the 14 samples in which the anomalous systemic arteries were available for analysis. CONCLUSIONS: There are no certain pathology diagnostic criteria for the diagnosis of PS. The detecting of the aberrant systematic artery and distinguishing it from the bronchial arteries corresponded to certain lung abnormalities are the keys to the accurate diagnosis of pulmonary sequestration in adult patients. We propose that the characteristic features of the anomalous arteries include: Originating from aorta and its main branches, adjacent to the sequestrated area
Emerging magnetism and anomalous Hall effect in iridate–manganite heterostructures
Nichols, John; Gao, Xiang; Lee, Shinbuhm; Meyer, Tricia L.; Freeland, John W.; Lauter, Valeria; Yi, Di; Liu, Jian; Haskel, Daniel; Petrie, Jonathan R.; Guo, Er-Jia; Herklotz, Andreas; Lee, Dongkyu; Ward, Thomas Z.; Eres, Gyula; Fitzsimmons, Michael R.; Lee, Ho Nyung
2016-01-01
Strong Coulomb repulsion and spin–orbit coupling are known to give rise to exotic physical phenomena in transition metal oxides. Initial attempts to investigate systems, where both of these fundamental interactions are comparably strong, such as 3d and 5d complex oxide superlattices, have revealed properties that only slightly differ from the bulk ones of the constituent materials. Here we observe that the interfacial coupling between the 3d antiferromagnetic insulator SrMnO3 and the 5d paramagnetic metal SrIrO3 is enormously strong, yielding an anomalous Hall response as the result of charge transfer driven interfacial ferromagnetism. These findings show that low dimensional spin–orbit entangled 3d–5d interfaces provide an avenue to uncover technologically relevant physical phenomena unattainable in bulk materials. PMID:27596572
Emerging magnetism and anomalous Hall effect in iridate–manganite heterostructures
Nichols, John; Gao, Xiang; Lee, Shinbuhm; ...
2016-09-06
We know strong Coulomb repulsion and spin–orbit coupling to give rise to exotic physical phenomena in transition metal oxides. Initial attempts to investigate systems, where both of these fundamental interactions are comparably strong, such as 3d and 5d complex oxide superlattices, have revealed properties that only slightly differ from the bulk ones of the constituent materials. Furthermore, we observe that the interfacial coupling between the 3d antiferromagnetic insulator SrMnO3 and the 5d paramagnetic metal SrIrO3 is enormously strong, yielding an anomalous Hall response as the result of charge transfer driven interfacial ferromagnetism. Our findings show that low dimensional spin–orbit entangledmore » 3d–5d interfaces provide an avenue to uncover technologically relevant physical phenomena unattainable in bulk materials.« less
Venusian atmospheric equilibrium chemistry at the Pioneer Venus anomalous event altitude
NASA Technical Reports Server (NTRS)
Craig, Roger A.
1994-01-01
No convincing explanation for the anomalous behavior of the Atmospheric Structure Experiment temperature sensors at approximately 13 km altitude has been found. It occurred on all of the widely-spaced probes, in a similar fashion. A preliminary effort has been made to determine atmospheric chemical species which might be present at 13 km. The purpose of this effort is to initiate suggestions of possible chemical interactions and to explore the effects of the presence of possible metal reactants including condensation. Equilibrium fractions of chemical species were calculated at a variety of conditions. Baseline calculations were made for the altitudes near 13 km. For comparison calculations were also made at 13 km but with the introduction of plausible metal atoms.
Emerging magnetism and anomalous Hall effect in iridate–manganite heterostructures
Nichols, John; Gao, Xiang; Lee, Shinbuhm; Meyer, Tricia L.; Freeland, John W.; Lauter, Valeria; Yi, Di; Liu, Jian; Haskel, Daniel; Petrie, Jonathan R.; Guo, Er-Jia; Herklotz, Andreas; Lee, Dongkyu; Ward, Thomas Z.; Eres, Gyula; Fitzsimmons, Michael R.; Lee, Ho Nyung
2016-09-06
We know strong Coulomb repulsion and spin–orbit coupling to give rise to exotic physical phenomena in transition metal oxides. Initial attempts to investigate systems, where both of these fundamental interactions are comparably strong, such as 3d and 5d complex oxide superlattices, have revealed properties that only slightly differ from the bulk ones of the constituent materials. Furthermore, we observe that the interfacial coupling between the 3d antiferromagnetic insulator SrMnO_{3} and the 5d paramagnetic metal SrIrO_{3} is enormously strong, yielding an anomalous Hall response as the result of charge transfer driven interfacial ferromagnetism. Our findings show that low dimensional spin–orbit entangled 3d–5d interfaces provide an avenue to uncover technologically relevant physical phenomena unattainable in bulk materials.
Anomalous preasymptotic colloid transport by hydrodynamic dispersion in microfluidic capillary flow
NASA Astrophysics Data System (ADS)
Fridjonsson, Einar Orn; Seymour, Joseph D.; Codd, Sarah L.
2014-07-01
The anomalous preasymptotic transport of colloids in a microfluidic capillary flow due to hydrodynamic dispersion is measured by noninvasive nuclear magnetic resonance (NMR). The data indicate a reduced scaling of mean squared displacement with time from the
Emerging magnetism and anomalous Hall effect in iridate-manganite heterostructures
NASA Astrophysics Data System (ADS)
Nichols, John; Gao, Xiang; Lee, Shinbuhm; Meyer, Tricia L.; Freeland, John W.; Lauter, Valeria; Yi, Di; Liu, Jian; Haskel, Daniel; Petrie, Jonathan R.; Guo, Er-Jia; Herklotz, Andreas; Lee, Dongkyu; Ward, Thomas Z.; Eres, Gyula; Fitzsimmons, Michael R.; Lee, Ho Nyung
2016-09-01
Strong Coulomb repulsion and spin-orbit coupling are known to give rise to exotic physical phenomena in transition metal oxides. Initial attempts to investigate systems, where both of these fundamental interactions are comparably strong, such as 3d and 5d complex oxide superlattices, have revealed properties that only slightly differ from the bulk ones of the constituent materials. Here we observe that the interfacial coupling between the 3d antiferromagnetic insulator SrMnO3 and the 5d paramagnetic metal SrIrO3 is enormously strong, yielding an anomalous Hall response as the result of charge transfer driven interfacial ferromagnetism. These findings show that low dimensional spin-orbit entangled 3d-5d interfaces provide an avenue to uncover technologically relevant physical phenomena unattainable in bulk materials.
Emerging magnetism and anomalous Hall effect in iridate-manganite heterostructures.
Nichols, John; Gao, Xiang; Lee, Shinbuhm; Meyer, Tricia L; Freeland, John W; Lauter, Valeria; Yi, Di; Liu, Jian; Haskel, Daniel; Petrie, Jonathan R; Guo, Er-Jia; Herklotz, Andreas; Lee, Dongkyu; Ward, Thomas Z; Eres, Gyula; Fitzsimmons, Michael R; Lee, Ho Nyung
2016-09-06
Strong Coulomb repulsion and spin-orbit coupling are known to give rise to exotic physical phenomena in transition metal oxides. Initial attempts to investigate systems, where both of these fundamental interactions are comparably strong, such as 3d and 5d complex oxide superlattices, have revealed properties that only slightly differ from the bulk ones of the constituent materials. Here we observe that the interfacial coupling between the 3d antiferromagnetic insulator SrMnO3 and the 5d paramagnetic metal SrIrO3 is enormously strong, yielding an anomalous Hall response as the result of charge transfer driven interfacial ferromagnetism. These findings show that low dimensional spin-orbit entangled 3d-5d interfaces provide an avenue to uncover technologically relevant physical phenomena unattainable in bulk materials.
Anomalous band inversion protected by symmetry in a topological insulator of the Kane-Mele model
NASA Astrophysics Data System (ADS)
Yu, Jie-Xiang; Che, J. G.
2016-01-01
Depositing Au on a graphene derivative, which involves substituting four C atoms with three N atoms in a 3 ×3 cell graphene, we realized a topological insulator of the Kane-Mele model with a gap of 50 meV surrounding the Dirac point of graphene. In this material, we observed an anomalous band inversion (BI) protected by the symmetry with character e of group C3 V. The symmetry constrains two e bands with mirror-symmetry combination and mirror-antisymmetry combination (MAC) of Au and N orbitals degenerate at Γ , whereas the interaction of π* of graphene on the e -MAC band tends to lift this degenerate, resulting in that the π* and e -MAC band exchange their orbital components near Γ , causing thus a discontinued BI.
Anomalous Series of Bands in the Edge Emission Spectra of CdS(О)
NASA Astrophysics Data System (ADS)
Morozova, N. K.; Kanakhin, A. A.; Galstyan, V. G.; Shnitnikov, A. S.
2015-02-01
The region of the edge emission spectrum of CdS(O) single crystals with cadmium excess is examined. An anomalous series of equidistant bands with leading line at 514 nm and phonon replicas has been revealed. These bands grow in intensity with increase of the excitation density up to 1026-1027 cm-3ṡs-1 at 80 K, and the leading line of the series is observed even at 300 K. It is shown that luminescence is conditioned by the exciton spectrum in perfect bulk single-crystals of CdO. Some characteristics of this spectrum are presented, in particular, the dependence on temperature, excitation intensity, composition and size of the crystals, and the LO interaction. The results experimentally confirm the theoretically calculated magnitude of the direct band gap of CdO.
Outcome of percutaneous nephrolithotomy in anomalous kidney: Is it different?
Prakash, Gaurav; Sinha, Rahul Janak; Jhanwar, Ankur; Bansal, Ankur; Singh, Vishwajeet
2017-01-01
Introduction: Various anomalous kidneys such as horseshoe kidney, crossed ectopic kidney, simple ectopic kidney, pelvic ectopic kidney, kidney with duplex system, and malrotated kidney are frequently associated with stone disease. Percutaneous nephrolithotomy (PCNL) is a challenging procedure in these patients because of abnormal orientation of kidney. Patients and Methods: Since 2005–2015, 86 patients underwent PCNL for stone removal in anomalous kidneys. Stone characteristics, type of calyceal puncture, number of punctures, need of relook procedures, mean hemoglobin drop, blood transfusion, mean operative time complications, mean hospital stay, stone free rate, and auxiliary procedure were analyzed. Results: Totally 91 sessions of PCNL was done in 86 patients including five of horseshoe kidney who had bilateral stone disease. Mean age, duration of symptoms, stone size, and hospital stay was 29.6 ± 12.6 years, 2.18 ± 1.41 years, 4.40 ± 1.16, and 4.17 ± 2.11 days, respectively. Sixteen patients underwent relook procedure, out of which only 6 could have complete stone clearance. Conclusion: PCNL in anomalous kidney is a safe and feasible procedure similar to normally located kidney, but requires careful preoperative planning and intra- and post-operative vigilance. PMID:28216924
Anomalous shape of magnetic loops in the Rayleigh region
NASA Astrophysics Data System (ADS)
Seeck, St.; Lambeck, M.
1995-11-01
According to its congruency property, the Preisach model demands an equivalent shape of magnetic minor loops, the so-called Rayleigh loops. We measured these loops with an inductive setup and noticed a different anomalous shape of Rayleigh loops which depends on the magnetic history. Special materials (particularly recording media) show a concave-convex shape in contrast to the normal biconvex shape. This anomalous shape can be explained by combining the Preisach model with the Stoner-Wohlfarth model. It follows from this explanation that the degree of the anomaly depends on the material, especially in how far it fulfills the conditions of the Stoner-Wohlfarth model. The experiments show the effect that is expected according to the material. In this way the measurement of the anomalous Rayleigh loops can be used as a new method to test the Stoner-Wohlfarth properties of a material. This is more effective than using the Henkel plot [G. Bertotti and V. Basso, J. Appl. Phys. 73, 5827 (1993)].
A structural framework for anomalous change detection and characterization
Prasad, Lakshman; Theiler, James P
2009-01-01
We present a spatially adaptive scheme for automatically searching a pair of images of a scene for unusual and interesting changes. Our motivation is to bring into play structural aspects of image features alongside the spectral attributes used for anomalous change detection (ACD). We leverage a small but informative subset of pixels, namely edge pixels of the images, as anchor points of a Delaunay triangulation to jointly decompose the images into a set of triangular regions, called trixels, which are spectrally uniform. Such decomposition helps in image regularization by simple-function approximation on a feature-adaptive grid. Applying ACD to this trixel grid instead of pixels offers several advantages. It allows: (1) edge-preserving smoothing of images, (2) speed-up of spatial computations by significantly reducing the representation of the images, and (3) the easy recovery of structure of the detected anomalous changes by associating anomalous trixels with polygonal image features. The latter facility further enables the application of shape-theoretic criteria and algorithms to characterize the changes and recognize them as interesting or not. This incorporation of spatial information has the potential to filter out some spurious changes, such as due to parallax, shadows, and misregistration, by identifying and filtering out those that are structurally similar and spatially pervasive. Our framework supports the joint spatial and spectral analysis of images, potentially enabling the design of more robust ACD algorithms.
A violation of universality in anomalous Fourier's law.
Hurtado, Pablo I; Garrido, Pedro L
2016-12-13
Since the discovery of long-time tails, it has been clear that Fourier's law in low dimensions is typically anomalous, with a size-dependent heat conductivity, though the nature of the anomaly remains puzzling. The conventional wisdom, supported by renormalization-group arguments and mode-coupling approximations within fluctuating hydrodynamics, is that the anomaly is universal in 1d momentum-conserving systems and belongs in the Lévy/Kardar-Parisi-Zhang universality class. Here we challenge this picture by using a novel scaling method to show unambiguously that universality breaks down in the paradigmatic 1d diatomic hard-point fluid. Hydrodynamic profiles for a broad set of gradients, densities and sizes all collapse onto an universal master curve, showing that (anomalous) Fourier's law holds even deep into the nonlinear regime. This allows to solve the macroscopic transport problem for this model, a solution which compares flawlessly with data and, interestingly, implies the existence of a bound on the heat current in terms of pressure. These results question the renormalization-group and mode-coupling universality predictions for anomalous Fourier's law in 1d, offering a new perspective on transport in low dimensions.
A violation of universality in anomalous Fourier’s law
NASA Astrophysics Data System (ADS)
Hurtado, Pablo I.; Garrido, Pedro L.
2016-12-01
Since the discovery of long-time tails, it has been clear that Fourier’s law in low dimensions is typically anomalous, with a size-dependent heat conductivity, though the nature of the anomaly remains puzzling. The conventional wisdom, supported by renormalization-group arguments and mode-coupling approximations within fluctuating hydrodynamics, is that the anomaly is universal in 1d momentum-conserving systems and belongs in the Lévy/Kardar-Parisi-Zhang universality class. Here we challenge this picture by using a novel scaling method to show unambiguously that universality breaks down in the paradigmatic 1d diatomic hard-point fluid. Hydrodynamic profiles for a broad set of gradients, densities and sizes all collapse onto an universal master curve, showing that (anomalous) Fourier’s law holds even deep into the nonlinear regime. This allows to solve the macroscopic transport problem for this model, a solution which compares flawlessly with data and, interestingly, implies the existence of a bound on the heat current in terms of pressure. These results question the renormalization-group and mode-coupling universality predictions for anomalous Fourier’s law in 1d, offering a new perspective on transport in low dimensions.
Nontrivial anomalous Hall effect in ultrathin Pt/permalloy bilayers
NASA Astrophysics Data System (ADS)
Zhang, Yanqing; Shan, Rong
2015-03-01
Anomalous Hall effect of Pt (2.5 nm)/permalloy bilayers with the thickness tPy = 0.6 ~10 nm; Pt/permalloy (2.2 nm) bilayers with the thickness tPt = 1.5 ~10 nm and Pt (2.5 nm)/permalloy (2.2 nm) bilayers with the post-annealing temperature 100 ~500° grown on MgO (001) substrates are investigated. The Pt/permalloy bilayer shows distinguished performance from the single permalloy layer due to the interfacial influence. Effective magnetic anisotropy of the bilayer with tPy <2.2 nm turns to be perpendicular to the film plane and it increases with decreasing measured temperature. More interestingly, the anomalous Hall effect is also greatly enhanced in these Pt/permalloy bilayers, comparing with that in bulk permalloy. The parameters presenting skew scattering, side jump and intrinsic contribution become extremely large, indicating a strong influence of spin orbit coupling coming from Pt/permalloy interface on the anomalous Hall effect.
Anomalous scaling of the penetration depth in nodal superconductors
NASA Astrophysics Data System (ADS)
She, Jian-Huang; Lawler, Michael J.; Kim, Eun-Ah
2015-07-01
Recent findings of anomalous superlinear scaling of low-temperature (T ) penetration depth (PD) in several nodal superconductors near putative quantum critical points suggest that the low-temperature PD can be a useful probe of quantum critical fluctuations in a superconductor. On the other hand, cuprates, which are poster child nodal superconductors, have not shown any such anomalous scaling of PD, despite growing evidence of quantum critical points (QCP). Then it is natural to ask when and how can quantum critical fluctuations cause anomalous scaling of PD? Carrying out the renormalization group calculation for the problem of two-dimensional superconductors with point nodes, we show that quantum critical fluctuations associated with a point group symmetry reduction result in nonuniversal logarithmic corrections to the T dependence of the PD. The resulting apparent power law depends on the bare velocity anisotropy ratio. We then compare our results to data sets from two distinct nodal superconductors: YBa2Cu3O6.95 and CeCoIn5. Considering all symmetry-lowering possibilities of the point group of interest, C4 v, we find our results to be remarkably consistent with YBa2Cu3O6.95 being near a vertical nematic QCP and CeCoIn5 being near a diagonal nematic QCP. Our results motivate a search for diagonal nematic fluctuations in CeCoIn5.
Mechanisms of anomalous dispersion in flow through heterogeneous porous media
NASA Astrophysics Data System (ADS)
Tyukhova, Alina; Dentz, Marco; Kinzelbach, Wolfgang; Willmann, Matthias
2016-11-01
We study the origins of anomalous dispersion in heterogeneous porous media in terms of the medium and flow properties. To identify and quantify the heterogeneity controls, we focus on porous media which are organized in assemblies of equally sized conductive inclusions embedded in a constant conductivity matrix. We study the behavior of particle arrival times for different conductivity distributions and link the statistical medium characteristics to large-scale transport using a continuous time random walk (CTRW) approach. The CTRW models particle motion as a sequence of transitions in space and time. We derive an explicit map of the conductivity onto the transition time distribution. The derived CTRW model predicts solute transport based on the conductivity distribution and the characteristic heterogeneity length. In this way, heavy tails in solute arrival times and anomalous particle dispersion as measured by the centered mean square displacement are directly related to the medium properties. These findings shed light on the mechanisms of anomalous dispersion in heterogeneous porous media, and provide a basis for the predictive modeling of large-scale transport.
Degree-strength correlation reveals anomalous trading behavior.
Sun, Xiao-Qian; Shen, Hua-Wei; Cheng, Xue-Qi; Wang, Zhao-Yang
2012-01-01
Manipulation is an important issue for both developed and emerging stock markets. Many efforts have been made to detect manipulation in stock markets. However, it is still an open problem to identify the fraudulent traders, especially when they collude with each other. In this paper, we focus on the problem of identifying the anomalous traders using the transaction data of eight manipulated stocks and forty-four non-manipulated stocks during a one-year period. By analyzing the trading networks of stocks, we find that the trading networks of manipulated stocks exhibit significantly higher degree-strength correlation than the trading networks of non-manipulated stocks and the randomized trading networks. We further propose a method to detect anomalous traders of manipulated stocks based on statistical significance analysis of degree-strength correlation. Experimental results demonstrate that our method is effective at distinguishing the manipulated stocks from non-manipulated ones. Our method outperforms the traditional weight-threshold method at identifying the anomalous traders in manipulated stocks. More importantly, our method is difficult to be fooled by colluded traders.
A violation of universality in anomalous Fourier’s law
Hurtado, Pablo I.; Garrido, Pedro L.
2016-01-01
Since the discovery of long-time tails, it has been clear that Fourier’s law in low dimensions is typically anomalous, with a size-dependent heat conductivity, though the nature of the anomaly remains puzzling. The conventional wisdom, supported by renormalization-group arguments and mode-coupling approximations within fluctuating hydrodynamics, is that the anomaly is universal in 1d momentum-conserving systems and belongs in the Lévy/Kardar-Parisi-Zhang universality class. Here we challenge this picture by using a novel scaling method to show unambiguously that universality breaks down in the paradigmatic 1d diatomic hard-point fluid. Hydrodynamic profiles for a broad set of gradients, densities and sizes all collapse onto an universal master curve, showing that (anomalous) Fourier’s law holds even deep into the nonlinear regime. This allows to solve the macroscopic transport problem for this model, a solution which compares flawlessly with data and, interestingly, implies the existence of a bound on the heat current in terms of pressure. These results question the renormalization-group and mode-coupling universality predictions for anomalous Fourier’s law in 1d, offering a new perspective on transport in low dimensions. PMID:27958318
Degree-Strength Correlation Reveals Anomalous Trading Behavior
Sun, Xiao-Qian; Shen, Hua-Wei; Cheng, Xue-Qi; Wang, Zhao-Yang
2012-01-01
Manipulation is an important issue for both developed and emerging stock markets. Many efforts have been made to detect manipulation in stock markets. However, it is still an open problem to identify the fraudulent traders, especially when they collude with each other. In this paper, we focus on the problem of identifying the anomalous traders using the transaction data of eight manipulated stocks and forty-four non-manipulated stocks during a one-year period. By analyzing the trading networks of stocks, we find that the trading networks of manipulated stocks exhibit significantly higher degree-strength correlation than the trading networks of non-manipulated stocks and the randomized trading networks. We further propose a method to detect anomalous traders of manipulated stocks based on statistical significance analysis of degree-strength correlation. Experimental results demonstrate that our method is effective at distinguishing the manipulated stocks from non-manipulated ones. Our method outperforms the traditional weight-threshold method at identifying the anomalous traders in manipulated stocks. More importantly, our method is difficult to be fooled by colluded traders. PMID:23082114
Saito, Ryo; Yokoyama, Jun'ichi; Nagata, Ryo E-mail: yokoyama@resceu.s.u-tokyo.ac.jp
2008-06-15
We show a textbook potential for single-field inflation, namely the Coleman-Weinberg model can induce double inflation and formation of primordial black holes (PBHs), because fluctuations that leave the horizon near the end of first inflation are anomalously enhanced at the onset of second inflation when the time-dependent mode turns into a growing mode rather than a decaying mode. The mass of PBHs produced in this mechanism with an appreciable density are distributed at certain intervals depending on the model parameters. We also calculate the effects of non-Gaussian statistics due to higher-order interactions on the abundance of PBHs, which turns out to be small.
NASA Astrophysics Data System (ADS)
Bertrand, Corentin L.; García-García, Antonio M.
2016-10-01
We study a one-dimensional XXZ spin chain in a random field on the metallic side of the many-body localization transition by level statistics. For a fixed interaction, and intermediate disorder below the many-body localization transition, we find that, asymptotically, the number variance grows faster than linear with a disorder-dependent exponent. This is consistent with the existence of an anomalous Thouless energy in the spectrum. In noninteracting disordered metals, this is an energy scale related to the typical time for a particle to diffuse across the sample. In the interacting case, it seems related to a more intricate anomalous diffusion process. This interpretation is not fully consistent with recent claims that for intermediate disorder, level statistics are described by a plasma model with power-law decaying interactions whose number variance grows slower than linear. As disorder is further increased, still on the metallic side, the Thouless energy is gradually washed out. In the range of sizes we can explore, level statistics are scale invariant and approach Poisson statistics at the many-body localization transition. Slightly below the many-body localization transition, spectral correlations, well described by critical statistics, are quantitatively similar to those of a high-dimensional, noninteracting, disordered conductor at the Anderson transition.
NASA Astrophysics Data System (ADS)
Riveiro, Maria; Falkman, Göran; Ziemke, Tom; Kronhamn, Thomas
2009-05-01
The goal of visual analytical tools is to support the analytical reasoning process, maximizing human perceptual, understanding and reasoning capabilities in complex and dynamic situations. Visual analytics software must be built upon an understanding of the reasoning process, since it must provide appropriate interactions that allow a true discourse with the information. In order to deepen our understanding of the human analytical process and guide developers in the creation of more efficient anomaly detection systems, this paper investigates how is the human analytical process of detecting and identifying anomalous behavior in maritime traffic data. The main focus of this work is to capture the entire analysis process that an analyst goes through, from the raw data to the detection and identification of anomalous behavior. Three different sources are used in this study: a literature survey of the science of analytical reasoning, requirements specified by experts from organizations with interest in port security and user field studies conducted in different marine surveillance control centers. Furthermore, this study elaborates on how to support the human analytical process using data mining, visualization and interaction methods. The contribution of this paper is twofold: (1) within visual analytics, contribute to the science of analytical reasoning with practical understanding of users tasks in order to develop a taxonomy of interactions that support the analytical reasoning process and (2) within anomaly detection, facilitate the design of future anomaly detector systems when fully automatic approaches are not viable and human participation is needed.
Hasnain, Sabeeha; McClendon, Christopher L.; Hsu, Monica T.; Jacobson, Matthew P.; Bandyopadhyay, Pradipta
2014-01-01
A new coarse-grained model of the E. coli cytoplasm is developed by describing the proteins of the cytoplasm as flexible units consisting of one or more spheres that follow Brownian dynamics (BD), with hydrodynamic interactions (HI) accounted for by a mean-field approach. Extensive BD simulations were performed to calculate the diffusion coefficients of three different proteins in the cellular environment. The results are in close agreement with experimental or previously simulated values, where available. Control simulations without HI showed that use of HI is essential to obtain accurate diffusion coefficients. Anomalous diffusion inside the crowded cellular medium was investigated with Fractional Brownian motion analysis, and found to be present in this model. By running a series of control simulations in which various forces were removed systematically, it was found that repulsive interactions (volume exclusion) are the main cause for anomalous diffusion, with a secondary contribution from HI. PMID:25180859
NASA Astrophysics Data System (ADS)
Jacobson, Matthew P.; O'Brien, Jonathan P.; Field, Robert W.
1998-09-01
We have identified, in dispersed fluorescence spectra of acetylene Ã 1Au→X˜ 1Σg+ emission, a series of bright states between 10 000 and 15 000 cm-1 of internal energy which display anomalously slow intramolecular vibrational redistribution. That is, these bright states display virtually no fractionation at internal energies at which the majority of other observed bright states are fractionated over several hundred cm-1 in a complicated fashion. The anomalous bright states are distinguished from the other nearly isoenergetic bright states only by the way in which the vibrational excitation is distributed among the CC stretch and trans bend modes; specifically, the anomalous bright states have relatively low excitation in the trans bend mode (v4⩽8), with the remainder of the vibrational excitation in the CC stretch mode (v2⩽6). A refinement of the acetylene global effective Hamiltonian permits detailed insight into the mechanism of the anomalously slow intramolecular vibrational redistribution, and reveals that the relatively simple fractionation patterns of these bright states can be adequately described in terms of a system of 4 interacting zero-order states which are coupled by Darling-Dennison bending resonances, vibrational l-resonance, and an anharmonic "3,245" resonance. The refined effective Hamiltonian also permits the assignment of similar, minimally perturbed bright states up to at least 17 500 cm-1 of internal energy.
Liu, Zhaocheng; Chen, Shuqi; Li, Jianxiong; Cheng, Hua; Li, Zhancheng; Liu, Wenwei; Yu, Ping; Xia, Ji; Tian, Jianguo
2014-12-01
We present a method of fully interferometric, controllable anomalous refraction efficiency by introducing cross-modulated incident light based on plasmonic metasurfaces. Theoretical analyses and numerical simulations indicate that the anomalous and ordinary refracted beams generated from two opposite-helicity incident beams and following the generalized Snell's law will have a superposition for certain incident angles, and the anomalous refraction efficiency can be dynamically controlled by changing the relative phase of the incident sources. As the incident wavelength nears the resonant wavelength of the plasmonic metasurfaces, two equal-amplitude incident beams with opposite helicity can be used to control the anomalous refraction efficiency. Otherwise, two unequal-amplitude incident beams with opposite helicity can be used to fully control the anomalous refraction efficiency. This Letter may offer a further step in the development of controllable anomalous refraction.
Karant, Y.J.
1981-07-01
From an analysis of 1460 projectile fragment collisions in nuclear research emulsion exposed to 2.1 A GeV /sup 16/O and 1.9 A GeV /sup 56/Fe at the Bevalac, evidence is presented for the existence of an anomalously short interaction mean free path of projectile fragments for the first several cm after emission. The result is significant to beyond the 3 standard deviation confidence level.
Three-loop cusp anomalous dimension and a conjecture for n loops
NASA Astrophysics Data System (ADS)
Kidonakis, Nikolaos
2016-05-01
I present analytical expressions for the massive cusp anomalous dimension in QCD through three loops, first calculated in 2014, in terms of elementary functions and ordinary polylogarithms. I observe interesting relations between the results at different loops and provide a conjecture for the n-loop cusp anomalous dimension in terms of the lower-loop results. I also present numerical results and simple approximate formulas for the cusp anomalous dimension relevant to top-quark production.
Aerosol Forcing of Climate Change and "Anomalous" Atmospheric Absorption
NASA Technical Reports Server (NTRS)
Hansen, James E.
1999-01-01
The forcings that drive long-term climate change are not known with an accuracy sufficient to define future climate change. Anthropogenic greenhouse gases (GHGs), which are well-measured, cause a strong positive (warming) forcing. But other, poorly measured, anthropogenic forcings, especially changes of atmospheric aerosols, clouds, and land-use patterns, cause a negative forcing that tends to offset greenhouse warming. We will focus on the role of aerosols as a climate forcing mechanism and the contribution that aerosols might make to the so- called "anomalous" atmospheric absorption that has been inferred from some atmospheric measurements.
Aerosol Forcing of Climate Change and Anomalous Atmospheric Absorption
NASA Technical Reports Server (NTRS)
Hansen, James E.
2000-01-01
The forcings that drive long-term climate change are not known with an accuracy sufficient to define future climate change, Anthropogenic greenhouse gases (GHGs), which are well-measured, cause a strong positive (warming) forcing. But other, poorly measured, anthropogenic forcings, especially changes of atmospheric aerosols, clouds, and land-use patterns, cause a negative forcing that tends to offset greenhouse warming. We will focus on the role of aerosols as a climate forcing mechanism and the contribution that aerosols might make to the so-called "anomalous" atmospheric absorption that has been inferred from some atmospheric measurements.
Use of sonification in the detection of anomalous events
NASA Astrophysics Data System (ADS)
Ballora, Mark; Cole, Robert J.; Kruesi, Heidi; Greene, Herbert; Monahan, Ganesh; Hall, David L.
2012-06-01
In this paper, we describe the construction of a soundtrack that fuses stock market data with information taken from tweets. This soundtrack, or auditory display, presents the numerical and text data in such a way that anomalous events may be readily detected, even by untrained listeners. The soundtrack generation is flexible, allowing an individual listener to create a unique audio mix from the available information sources. Properly constructed, the display exploits the auditory system's sensitivities to periodicities, to dynamic changes, and to patterns. This type of display could be valuable in environments that demand high levels of situational awareness based on multiple sources of incoming information.
Quantum anomalous Hall effect in topological insulator memory
Jalil, Mansoor B. A.; Tan, S. G.; Siu, Z. B.
2015-05-07
We theoretically investigate the quantum anomalous Hall effect (QAHE) in a magnetically coupled three-dimensional-topological insulator (3D-TI) system. We apply the generalized spin-orbit coupling Hamiltonian to obtain the Hall conductivity σ{sup xy} of the system. The underlying topology of the QAHE phenomenon is then analyzed to show the quantization of σ{sup xy} and its relation to the Berry phase of the system. Finally, we analyze the feasibility of utilizing σ{sup xy} as a memory read-out in a 3D-TI based memory at finite temperatures, with comparison to known magnetically doped 3D-TIs.
Quantum anomalous Hall effect in stable dumbbell stanene
NASA Astrophysics Data System (ADS)
Zhang, Huisheng; Zhang, Jiayong; Zhao, Bao; Zhou, Tong; Yang, Zhongqin
2016-02-01
Topological property of the dumbbell (DB) stanene, more stable than the stanene with a honeycomb lattice, is investigated by using ab initio methods. The magnetic DB stanene demonstrates an exotic quantum anomalous Hall (QAH) effect due to inversion of the Sn spin-up px,y and spin-down pz states. The QAH gap is found to be opened at Γ point rather than the usual K and K' points, beneficial to observe the effect in experiments. When a 3% tensile strain is applied, a large nontrivial gap (˜50 meV) is achieved. Our results provide another lighthouse for realizing QAH effects in two-dimensional systems.
Linear dissipative soliton in an anomalous-dispersion fiber laser.
Wang, Ruixin; Dai, Yitang; Yin, Feifei; Xu, Kun; Li, Jianqiang; Lin, Jintong
2014-12-01
We report on the generation of linear dissipative soliton (LDS) from an erbium-doped actively mode-locked fiber laser. We show that depending on the down-chirping effect of quadratic phase modulation, instead of the fiber nonlinear Kerr effect in an all-normal-dispersion (ANDi) cavity, stable LDS can be realized in the linear dissipative system. The DS operation of ANDi laser and LDS operation of anomalous dispersion laser are experimentally investigated and compared, and the formation mechanisms of the DS and LDS are discussed. Finally, optical frequency comb generated by the LDS laser is demonstrated.
Measurements of Anomalous Dispersion Made with X-Ray Interferometers
NASA Astrophysics Data System (ADS)
Hart, M.; Siddons, D. P.
1981-05-01
Absolute measurements of the anomalous dispersion constants f' for zirconium, niobium and molybdenum made with a computer controlled X-ray interferometer have achieved a precision that permits systematic comparison with the available theories. Measurements were made at about 80 wavelengths within ±3 keV of the elements' K-absorption edge. After modification, to minimize computational errors, the theory of Cromer and Liberman is in satisfactory agreement with the results obtained so far, but small systematic differences between theory and experiment are apparent. Further work on a wide variety of elements and over a wide wavelength band is in progress.
Anomalous left main coronary artery detected by CT angiography.
Forte, Ernesto; Inglese, Marianna; Infante, Teresa; Schiano, Concetta; Napoli, Claudio; Soricelli, Andrea; Salvatore, Marco; Tedeschi, Carlo
2016-10-01
The growing improvements of computed tomography have made this technique more and more available for cardiac evaluation. Coronary artery anomalies (CAAs) are often incidental findings in subjects with suspected coronary artery disease (CAD) undergoing coronary angiography or computed tomography coronary angiography (CTCA). In some cases, CAAs can be clinically relevant so their identification could change radically patient management and treatment. We report the case of a 68-year-old male patient with known CAD and associated anomalous origination of the left coronary artery from the opposite sinus.
Anomalous thermoelectricity in strained Bi2Te3 films.
Liu, Yucong; Chen, Jiadong; Deng, Huiyong; Hu, Gujin; Zhu, Daming; Dai, Ning
2016-09-07
Bi2Te3-based alloys have been intensively used for thermoelectric coolers and generators due to their high Seebeck coefficient S. So far, efforts to improve the S have been made mostly on changing the structures and components. Herein, we demonstrate an anomalous thermoelectricity in strained Bi2Te3 films, i.e., the value of S is obviously changed after reversing the direction of temperature gradient. Further theoretical and experimental analysis shows that it originates from the coupling of thermoelectric and flexoelectric effects caused by a stress gradient. Our finding provides a new avenue to adjust the S of Bi2Te3-based thermoelectric materials through flexoelectric polarization.
Anomalous polarization profiles in sunspots: possible origin of umbral flashes
Socas-Navarro; Trujillo Bueno J; Ruiz Cobo B
2000-05-26
We present time-series spectropolarimetric observations of sunspots in the Ca II infrared triplet lines, which show a periodic occurrence of anomalous, asymmetric, circular polarization profiles in the umbral chromosphere. The profiles may be caused by the periodic development of an unresolved atmospheric component in a downward flowing magnetized environment. This active component with upward directed velocities as high as 10 kilometers per second is connected to the umbral flash (UF) phenomenon. We can explain the observations with a semiempirical model of the chromospheric oscillation and of the sunspot magnetized atmospheric plasma during a UF event.
Using support vector machines for anomalous change detonation
Theiler, James P; Steinwart, Ingo; Llamocca, Daniel
2010-01-01
We cast anomalous change detection as a binary classification problem, and use a support vector machine (SVM) to build a detector that does not depend on assumptions about the underlying data distribution. To speed up the computation, our SVM is implemented, in part, on a graphical processing unit. Results on real and simulated anomalous changes are used to compare performance to algorithms which effectively assume a Gaussian distribution. In this paper, we investigate the use of support vector machines (SVMs) with radial basis kernels for finding anomalous changes. Compared to typical applications of SVMs, we are operating in a regime of very low false alarm rate. This means that even for relatively large training sets, the data are quite meager in the regime of operational interest. This drives us to use larger training sets, which in turn places more of a computational burden on the SVM. We initially considered three different approaches to to address the need to work in the very low false alarm rate regime. The first is a standard SVM which is trained at one threshold (where more reliable estimates of false alarm rates are possible) and then re-thresholded for the low false alarm rate regime. The second uses the same thresholding approach, but employs a so-called least squares SVM; here a quadratic (instead of a hinge-based) loss function is employed, and for this model, there are good theoretical arguments in favor of adjusting the threshold in a straightforward manner. The third approach employs a weighted support vector machine, where the weights for the two types of errors (false alarm and missed detection) are automatically adjusted to achieve the desired false alarm rate. We have found in previous experiments (not shown here) that the first two types can in some cases work well, while in other cases they do not. This renders both approaches unreliable for automated change detection. By contrast, the third approach reliably produces good results, but at
Enhanced thermoelectric performance and anomalous seebeck effects in topological insulators.
Xu, Yong; Gan, Zhongxue; Zhang, Shou-Cheng
2014-06-06
Improving the thermoelectric figure of merit zT is one of the greatest challenges in material science. The recent discovery of topological insulators (TIs) offers new promise in this prospect. In this work, we demonstrate theoretically that zT is strongly size dependent in TIs, and the size parameter can be tuned to enhance zT to be significantly greater than 1. Furthermore, we show that the lifetime of the edge states in TIs is strongly energy dependent, leading to large and anomalous Seebeck effects with an opposite sign to the Hall effect. These striking properties make TIs a promising material for thermoelectric science and technology.
Anomalous thermoelectricity in strained Bi2Te3 films
NASA Astrophysics Data System (ADS)
Liu, Yucong; Chen, Jiadong; Deng, Huiyong; Hu, Gujin; Zhu, Daming; Dai, Ning
2016-09-01
Bi2Te3-based alloys have been intensively used for thermoelectric coolers and generators due to their high Seebeck coefficient S. So far, efforts to improve the S have been made mostly on changing the structures and components. Herein, we demonstrate an anomalous thermoelectricity in strained Bi2Te3 films, i.e., the value of S is obviously changed after reversing the direction of temperature gradient. Further theoretical and experimental analysis shows that it originates from the coupling of thermoelectric and flexoelectric effects caused by a stress gradient. Our finding provides a new avenue to adjust the S of Bi2Te3-based thermoelectric materials through flexoelectric polarization.
Anomalous Single Coronary Artery Presenting with Acute Myocardial Infarction
Ramachandran, Padmakumar; Krishnan, Anand Muthu; Chowdary, Ravella Keerthika; Malpe, Umesh Pai
2016-01-01
The anomalous origin of the entire coronary system from the right coronary sinus is a very rare anomaly. Here a patient with this rare anomaly, who developed acute coronary syndrome, requiring revascularization, is presented and treated successfully. His coronary angiographic findings are also discussed. We would like to highlight the rarity of the origin of all 3 coronary arteries from a single coronary trunk. The case also highlights the importance of using Amplantzer AR1 guiding catheter for such anatomical variations arising in the right coronary cusp. PMID:28208910
Observation of anomalous Iron Ion Charge Distribution in FTU
Finkenthal, M; May, M; Pacella, D; Leigheb, M; Zagorski, R; Mattioli, M; Fournier, K
2003-11-14
Iron coming from the poloidal limiter or the stainless steel vessel is an important intrinsic impurity in the FTU tokamak discharges, and X-ray and VUV spectroscopy provide useful information about the impurity behavior. The iron ion charge state distribution, as usual for tokamaks, is analyzed assuming a collisional radiative model and an anomalous perpendicular diffusion. In our experiment the iron ionization level depends, as it is expected, on central electron temperature (fig. 1), but the ion charge state distribution shows a different behavior when the first wall material or the iron source are changed.
Anomalous resistivity and the evolution of magnetic field topology
NASA Technical Reports Server (NTRS)
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.
The structural origin of anomalous properties of liquid water
Nilsson, Anders; Pettersson, Lars G. M.
2015-01-01
Water is unique in its number of unusual, often called anomalous, properties. When hot it is a normal simple liquid; however, close to ambient temperatures properties, such as the compressibility, begin to deviate and do so increasingly on further cooling. Clearly, these emerging properties are connected to its ability to form up to four well-defined hydrogen bonds allowing for different local structural arrangements. A wealth of new data from various experiments and simulations has recently become available. When taken together they point to a heterogeneous picture with fluctuations between two classes of local structural environments developing on temperature-dependent length scales. PMID:26643439
Anomalous diffusion of poly(ethylene oxide) in agarose gels.
Brenner, Tom; Matsukawa, Shingo
2016-11-01
We report on the effect of probe size and diffusion time of poly(ethylene) oxide in agarose gels. Time-dependence of the diffusion coefficient, reflecting anomalous diffusion, was observed for poly(ethylene) oxide chains with hydrodynamic radii exceeding about 20nm at an agarose concentration of 2%. The main conclusion is that the pore distribution includes pores that are only several nm across, in agreement with scattering reports in the literature. Interpretation of the diffusion coefficient dependence on the probe size based on a model of entangled rigid rods yielded a rod length of 72nm.
Anomalous scaling in an age-dependent branching model.
Keller-Schmidt, Stephanie; Tuğrul, Murat; Eguíluz, Víctor M; Hernández-García, Emilio; Klemm, Konstantin
2015-02-01
We introduce a one-parametric family of tree growth models, in which branching probabilities decrease with branch age τ as τ(-α). Depending on the exponent α, the scaling of tree depth with tree size n displays a transition between the logarithmic scaling of random trees and an algebraic growth. At the transition (α=1) tree depth grows as (logn)(2). This anomalous scaling is in good agreement with the trend observed in evolution of biological species, thus providing a theoretical support for age-dependent speciation and associating it to the occurrence of a critical point.
Anomalous Hall Effect in a Feromagnetic Rare-Earth Cobalite
NASA Technical Reports Server (NTRS)
Samoilov, A. V.; Yeh, N. C.; Vasquez, R. P.
1996-01-01
Rare-Earth manganites and cobalites with the perovskite structure have been a subject of great recent interest because their electrical resistance changes significantly when a magnetic field is applied...we have studied the Hall effect in thin film La(sub 0.5)Ca(sub 0.5)CoO(sub 3) material and have obtained convincing evidence fo the so called anomalous Hall effect, typical for magnetic metals...Our results suggest that near the ferromagnetic ordering temperature, the dominant electron scattering mechanism is the spin fluctuation.
Observation of anomalous leakage increase of narrow and short BCPMOS
NASA Astrophysics Data System (ADS)
Xu, Y. Z.; Pohland, O.; Cai, C.; Puchner, H.
2004-07-01
Leakage performance of BCPMOS (Buried channel PMOS) is investigated by experimentally varying the LDD implant conditions. An anomalous leakage increase with Boron LDD implant is observed for a small geometry (narrow and short) PMOS. Experimental results indicate that the increase of leakage current for narrow and short channel PMOS can be explained by boron piling up at the edge of STI isolation and from source/drain towards the middle of channel. Further confirmation of boron piling up is proven by the surface channel NMOS threshold voltage. Based on the leakage sensitivity, BCPMOS LDD is optimized to reduce leakage current for the small geometry transistors.
Is Diffusion Anomalous in Two-Dimensional Yukawa Liquids?
Ott, T.; Bonitz, M.
2009-11-06
There have recently been many predictions of 'superdiffusion' in two-dimensional strongly coupled Yukawa systems, both by computer simulations and in dusty plasma experiments, with substantially varying diffusion exponents. Here we show that the results crucially depend on the strength of dissipation and the time instant of the measurement. For sufficiently large friction even subdiffusion is possible. However, there are strong indications that, in the long-time limit, anomalous diffusion vanishes and the system returns to normal diffusion, for dissipative as well as for frictionless systems.
Anomalous Phase Separation Kinetics Observed in a Micelle Solution
NASA Astrophysics Data System (ADS)
Wilcoxon, Jess P.; Martin, James E.; Odinek, Judy
1995-08-01
We report a real-time, two-dimensional light scattering study of the evolution of structure in a two-component nonionic micelle system undergoing phase separation. We find that the structure of the domains is qualitatively similar to that observed in binary fluid systems, with some anomalies observed. However, compared to the Lifshitz-Slyozov prediction for simple binary fluids, the domain growth is unexpectedly slow. In fact, the growth kinetics can be empirically described as a stretched exponential approach to a pinned domain size. This anomalous behavior may be due to the ability of the spherical micelles to reorganize into more complex structures.
Anomalous Metapopulation Dynamics on Scale-Free Networks
NASA Astrophysics Data System (ADS)
Fedotov, Sergei; Stage, Helena
2017-03-01
We model transport of individuals across a heterogeneous scale-free network where a few weakly connected nodes exhibit heavy-tailed residence times. Using the empirical law of the axiom of cumulative inertia and fractional analysis, we show that "anomalous cumulative inertia" overpowers highly connected nodes in attracting network individuals. This fundamentally challenges the classical result that individuals tend to accumulate in high-order nodes. The derived residence time distribution has a nontrivial U shape which we encounter empirically across human residence and employment times.
Dynamo and anomalous transport in the reversed field pinch
Prager, S.C.
1998-08-01
The reversed field pinch is an effective tool to study the macroscopic consequences of magnetic fluctuations, such as the dynamo effect and anomalous transport. Several explanations exist for the dynamo (the self-generation of plasma current)--the MHD dynamo, the kinetic dynamo, and the diamagnetic dynamo. There is some experimental evidence for each, particularly from measurements of ion velocity and electron pressure fluctuations. Magnetic fluctuations are known to produce energy and particle flux in the RFP core. Current profile control is able to decrease fluctuation-induced transport by a factor of five. Improved confinement regimes are also obtained at deep reversal and, possibly, with flow shear.
Anomalous compression in ? - an experimental and computational study
NASA Astrophysics Data System (ADS)
Shekar, N. V. Chandra; Sahu, P. Ch; Rajagopalan, M.; Yousuf, Mohammad; Rajan, K. Govinda
1997-07-01
High-pressure x-ray diffraction experiments were performed on 0953-8984/9/27/016/img9 up to 23 GPa. Anomalous compressibility behaviour of the system was observed in the pressure range 7 - 14 GPa. The experiments are compared with similar observations in 0953-8984/9/27/016/img10 and 0953-8984/9/27/016/img11. Band structure calculations have been performed to look for a possible explanation of this behaviour through the concept of electron transfer from the f to the d orbitals.
Recurrent Massive Epistaxis from an Anomalous Posterior Ethmoid Artery
Mattioli, Francesco; Alberici, Maria Paola; Presutti, Livio
2016-01-01
A 50-year-old man, with no previous history of epistaxis, was hospitalized at our facility for left recurrent posterior epistaxis. The patient underwent surgical treatment three times and only the operator's experience and radiological support (cranial angiography) allowed us to control the epistaxis and stop the bleeding. The difficult bleeding management and control was attributed to an abnormal course of the left posterior ethmoidal artery. When bleeding seems to come from the roof of the nasal cavity, it is important to identify the ethmoid arteries always bearing in mind the possible existence of anomalous courses. PMID:28025632
On the anomalous afterglow seen in a chameleon afterglow search
Steffen, Jason H.; Baumbaugh, Alan; Chou, Aaron S.; Tomlin, Ray; Upadhye, Amol; /Argonne, PHY
2012-05-01
We present data from our investigation of the anomalous orange-colored afterglow that was seen in the GammeV Chameleon Afterglow Search (CHASE). These data include information about the broadband color of the observed glow, the relationship between the glow and the temperature of the apparatus, and other data taken prior to, and during the science operations of CHASE. While differing in several details, the generic properties of the afterglow from CHASE are similar to luminescence seen in some vacuum compounds. Contamination from this, or similar, luminescent signatures will likely impact the design of implementation of future experiments involving single photon detectors and high intensity light sources in a cryogenic environment.
Anomalous Raman spectra from La2CuO4
NASA Astrophysics Data System (ADS)
Burns, Gerald; Dacol, F. H.
1990-03-01
We show that some published Raman spectra from the superconductors (La2-xSrx)CuO4 and La2NiO4 are incorrect. We believe that these spectra were obtained when the samples were ``burnt'' by the focused laser beam and were actually due to La2O3. Similar anomalous results can be obtained when starting with Nd2CuO4 where the spectra come from Nd2O3. A spectrum distinctly different from those of La2O3 or Nd2O3 is obtained from Y2O3.
Constraints on anomalous top quark couplings at the LHC
Rizzo, T.G.
1996-09-01
Measurements of distributions associated with the pair production of top quarks at the LHC can be used to constrain (or observe) the anomalous chromomagnetic dipole moment(k) of the top. For example, using either the tt(bar) invariant mass or the Pt distribution of top we find that sensitivities to ; k; of order 0.05 are obtainable with 100 /fb of integrated luminosity. This is similar in magnitude to what can be obtained at a 500 GeV NLC with an integrated luminosity of 50 /fb through an examination of the e(+)e(-) right arrow tt(bar)g process.
Anomalous Radiative Trapping in Laser Fields of Extreme Intensity
NASA Astrophysics Data System (ADS)
Gonoskov, A.; Bashinov, A.; Gonoskov, I.; Harvey, C.; Ilderton, A.; Kim, A.; Marklund, M.; Mourou, G.; Sergeev, A.
2014-07-01
We demonstrate that charged particles in a sufficiently intense standing wave are compressed toward, and oscillate synchronously at, the antinodes of the electric field. We call this unusual behavior anomalous radiative trapping (ART). We show using dipole pulses, which offer a path to increased laser intensity, that ART opens up new possibilities for the generation of radiation and particle beams, both of which are high energy, directed, and collimated. ART also provides a mechanism for particle control in high-intensity quantum-electrodynamics experiments.
Anomalous accretion activity and the spotted nature of the DQ Tau binary system
Bary, Jeffrey S.; Petersen, Michael S.
2014-09-01
We report the detection of an anomalous accretion flare in the tight eccentric pre-main-sequence binary system DQ Tau. In a multi-epoch survey consisting of randomly acquired low- to moderate-resolution near-infrared spectra obtained over a period of almost 10 yr, we detect a significant and simultaneous brightening of four standard accretion indicators (Ca II infrared triplet, the Paschen and Brackett series H I lines, and He I 1.083 μm), on back-to-back nights (φ = 0.372 and 0.433) with the flare increasing in strength as the system approached apastron (φ = 0.5). The mass accretion rate measured for the anomalous flare is nearly an order of magnitude stronger than the average quiescent rate. While previous observations established that frequent, periodic accretion flares phased with periastron passages occur in this system, these data provide evidence that orbitally modulated accretion flares occur near apastron, when the stars make their closest approach to the circumbinary disk. The timing of the flare suggests that this outburst is due to interactions of the stellar cores (or the highly truncated circumstellar disks) with material in non-axisymmetric structures located at the inner edge of the circumbinary disk. We also explore the optical/infrared spectral type mismatch previously observed for T Tauri stars (TTSs) and successfully model the shape of the spectra from 0.8 to 1.0 μm and the strengths of the TiO and FeH bands as manifestations of large cool spots on the surfaces of the stellar companions in DQ Tau. These findings illustrate that a complete model of near-infrared spectra of many TTSs must include parameters for spot filling factors and temperatures.
The dimensionality of color vision in carriers of anomalous trichromacy.
Jordan, Gabriele; Deeb, Samir S; Bosten, Jenny M; Mollon, J D
2010-07-01
Some 12% of women are carriers of the mild, X-linked forms of color vision deficiencies called "anomalous trichromacy." Owing to random X chromosome inactivation, their retinae must contain four classes of cone rather than the normal three; and it has previously been speculated that these female carriers might be tetrachromatic, capable of discriminating spectral stimuli that are indistinguishable to the normal trichromat. However, the existing evidence is sparse and inconclusive. Here, we address the question using (a) a forced-choice version of the Rayleigh test, (b) a test using multidimensional scaling to reveal directly the dimensionality of the participants' color space, and (c) molecular genetic analyses to estimate the X-linked cone peak sensitivities of a selected sample of strong candidates for tetrachromacy. Our results suggest that most carriers of color anomaly do not exhibit four-dimensional color vision, and so we believe that anomalous trichromacy is unlikely to be maintained by an advantage to the carriers in discriminating colors. However, 1 of 24 obligate carriers of deuteranomaly exhibited tetrachromatic behavior on all our tests; this participant has three well-separated cone photopigments in the long-wave spectral region in addition to her short-wave cone. We assess the likelihood that behavioral tetrachromacy exists in the human population.
Independent Confirmation of the Pioneer 10 Anomalous Acceleration
NASA Technical Reports Server (NTRS)
Markwardt, Craig B.
2002-01-01
I perform an independent analysis of radio Doppler tracking data from the Pioneer 10 spacecraft for the time period 1987-1994. All of the tracking data were taken from public archive sources, and the analysis tools were developed independently by myself. I confirm that an apparent anomalous acceleration is acting on the Pioneer 10 spacecraft, which is not accounted for by present physical models of spacecraft navigation. My best fit value for the acceleration, including corrections for systematic biases and uncertainties, is (8.60 plus or minus 1.34) x 10(exp -8) centimeters per second, directed towards the Sun. This value compares favorably to previous results. I examine the robustness of my result to various perturbations of the analysis method, and find agreement to within plus or minus 5%. The anomalous acceleration is reasonably constant with time, with a characteristic variation time scale of greater than 70 yr. Such a variation timescale is still too short to rule out on-board thermal radiation effects, based on this particular Pioneer 10 data set.
Nonlinear dynamics induced anomalous Hall effect in topological insulators.
Wang, Guanglei; Xu, Hongya; Lai, Ying-Cheng
2016-01-28
We uncover an alternative mechanism for anomalous Hall effect. In particular, we investigate the magnetisation dynamics of an insulating ferromagnet (FM) deposited on the surface of a three-dimensional topological insulator (TI), subject to an external voltage. The spin-polarised current on the TI surface induces a spin-transfer torque on the magnetisation of the top FM while its dynamics can change the transmission probability of the surface electrons through the exchange coupling and hence the current. We find a host of nonlinear dynamical behaviors including multistability, chaos, and phase synchronisation. Strikingly, a dynamics mediated Hall-like current can arise, which exhibits a nontrivial dependence on the channel conductance. We develop a physical understanding of the mechanism that leads to the anomalous Hall effect. The nonlinear dynamical origin of the effect stipulates that a rich variety of final states exist, implying that the associated Hall current can be controlled to yield desirable behaviors. The phenomenon can find applications in Dirac-material based spintronics.
Optimize Short Term load Forcasting Anomalous Based Feed Forward Backpropagation
NASA Astrophysics Data System (ADS)
Mulyadi, Y.; Abdullah, A. G.; Rohmah, K. A.
2017-03-01
This paper contains the Short-Term Load Forecasting (STLF) using artificial neural network especially feed forward back propagation algorithm which is particularly optimized in order to getting a reduced error value result. Electrical load forecasting target is a holiday that hasn’t identical pattern and different from weekday’s pattern, in other words the pattern of holiday load is an anomalous. Under these conditions, the level of forecasting accuracy will be decrease. Hence we need a method that capable to reducing error value in anomalous load forecasting. Learning process of algorithm is supervised or controlled, then some parameters are arranged before performing computation process. Momentum constant a value is set at 0.8 which serve as a reference because it has the greatest converge tendency. Learning rate selection is made up to 2 decimal digits. In addition, hidden layer and input component are tested in several variation of number also. The test result leads to the conclusion that the number of hidden layer impact on the forecasting accuracy and test duration determined by the number of iterations when performing input data until it reaches the maximum of a parameter value.
Block diagonal representations for covariance based anomalous change detectors
Matsekh, Anna; Theiler, James
2009-01-01
Change detection methods are of crucial importance in many remote sensing applications such as monitoring and surveillance, where the goal is to identify and separate changes of interest from pervasive changes inevitably present in images taken at different times and in different environmental and illumination conditions. Anomalous change detection (ACD) methods aim to identify rare, unusual, or anomalous changes among the changes of interest. Covariance-based ACD methods provide a powerful tool for detection of unusual changes in hyper-spectral images. In this paper we study the properties of the eigenvalue spectra of a family of ACD matrices in order to better understand the algebraic and numerical behavior of the covariance-based quadratic ACD methods. We propose to use singular vectors of covariance matrices of two hyper-spectral images in whitened coordinates for obtaining block-diagonal representations of the matrices of quadratic ACD methods. SVD transformation gives an equivalent representation of ACD matrices in compact block-diagonal form. In the paper we show that the eigenvalue spectrum of a block-diagonal ACD matrix can be identified analytically as a function of the singular value spectrum of the corresponding covariance matrix in whitened coordinates.
Brain activation inhomogeneity highlighted by the Isotropic Anomalous Diffusion filter.
Senra Filho, Antonio Carlos da S; Rondinoni, Carlo; dos Santos, Antonio Carlos; Murta, Luiz O
2014-01-01
The visual appealing nature of the now popular BOLD fMRI may give the false impression of extreme simplicity, as if the the functional maps could be generated with the press of a single button. However, one can only get plausible maps after long and cautious processing, considering that time and noise come into play during acquisition. One of the most popular ways to account for noise and individual variability in fMRI is the use of a Gaussian spatial filter. Although very robust, this filter may introduce excessive blurring, given the strong dependence of results on the central voxel value. Here, we propose the use of the Isotropic Anomalous Diffusion (IAD) approach, aiming to reduce excessive homogeneity while retaining the natural variability of signal across brain space. We found differences between Gaussian and IAD filters in two parameters gathered from Independent Component maps (ICA), identified on brain areas responsible for auditory processing during rest. Analysis of data gathered from 7 control subjects shows that the IAD filter rendered more localized active areas and higher contrast-to-noise ratios, when compared to equivalent Gaussian filtered data (Student t-test, p<0.05). The results seem promising, since the anomalous filter performs satisfactorily in filtering noise with less distortion of individual localized brain responses.
Anomalous diffusion of electromagnetic eddy currents in geological formations
NASA Astrophysics Data System (ADS)
Weiss, Chester J.; Everett, Mark E.
2007-08-01
Controlled-source electromagnetic (EM) induction in some geological formations is shown here to be compactly described by an anomalous subdiffusion process. Such a process, which is not universal, is governed by a fractional diffusion equation or alternatively the convolutional form of Ohm's law. A subdiffusing eddy current vortex, or electromagnetic smoke ring, propagates in such a way that its position of median intensity overruns its position of peak intensity. This behavior is not allowed in classical diffusion but is a simple consequence of diffusion within a stationary fractal medium. A similar analysis has been applied to understand heavy-tailed traveltime distributions that appear in certain hydrological time series. The tell-tale signature of anomalous electromagnetic diffusion is a slope β of the magnetic zero-crossing moveout curve that is constant with transmitter-receiver (RX) offset and significantly different from unity. Neither lateral heterogeneity nor unixial anisotropy can generate such a constant-slope moveout curve with an economy of model parameters. Controlled-source EM data from two sites in Texas and one in New Mexico are used in this study to test the eddy current subdiffusion hypothesis.
Anomalous magnetic properties of mechanically milled cobalt oxide nanoparticles.
Mishra, S R; Dubenko, I; Losby, J; Ghosh, l K; Khan, M; Ali, N
2005-12-01
Defect induced magnetic properties of CoO nanoparticles produced via mechanical ball milling have been assessed by detailed magnetic measurements. A progressive decrease in the particle size and a concomitant increase in the induced strain have been observed with the milling times. The mechanically milled nanoparticles of CoO exhibit anomalous magnetic properties such as FM hysteresis when compared with the unmilled CoO sample. The presence of weak ferromagnetism, with a highest value of magnetization of 0.532 emu/g at 10 K in the 100 h milled sample, is attributed to the uncompensated surface spins resulting from induced surface defects via mechanical milling. The ZFC coercive force, measured at 10 K, increases with milling time reaching a maximum value of 1066 Oe for the 100 h milled sample. The temperature dependent field-cooled (FC) and zero-field-cooled (ZFC) magnetic measurements indicate a presence of an exchange bias field arising from uncompensated moments generated by mechanical strain and the antiferromagnetic (AFM) core. The exchange bias field measured at 10 K reaches a value 210 Oe for the 50 h milled sample and decreases upon prolonged milling. The exchange bias field vanishes at a temperature approximately 200 K, a temperature much lower than the Neel temperature of CoO (TN approximately 291 K). The observed anomalous magnetic behavior of CoO could be interpreted in terms of the exchanged bias FM-AFM model.
Nonlinear dynamics induced anomalous Hall effect in topological insulators
NASA Astrophysics Data System (ADS)
Wang, Guanglei; Xu, Hongya; Lai, Ying-Cheng
2016-01-01
We uncover an alternative mechanism for anomalous Hall effect. In particular, we investigate the magnetisation dynamics of an insulating ferromagnet (FM) deposited on the surface of a three-dimensional topological insulator (TI), subject to an external voltage. The spin-polarised current on the TI surface induces a spin-transfer torque on the magnetisation of the top FM while its dynamics can change the transmission probability of the surface electrons through the exchange coupling and hence the current. We find a host of nonlinear dynamical behaviors including multistability, chaos, and phase synchronisation. Strikingly, a dynamics mediated Hall-like current can arise, which exhibits a nontrivial dependence on the channel conductance. We develop a physical understanding of the mechanism that leads to the anomalous Hall effect. The nonlinear dynamical origin of the effect stipulates that a rich variety of final states exist, implying that the associated Hall current can be controlled to yield desirable behaviors. The phenomenon can find applications in Dirac-material based spintronics.
Anomalous Temperature Dependence of the Band Gap in Black Phosphorus.
Villegas, Cesar E P; Rocha, A R; Marini, Andrea
2016-08-10
Black phosphorus (BP) has gained renewed attention due to its singular anisotropic electronic and optical properties that might be exploited for a wide range of technological applications. In this respect, the thermal properties are particularly important both to predict its room temperature operation and to determine its thermoelectric potential. From this point of view, one of the most spectacular and poorly understood phenomena is indeed the BP temperature-induced band gap opening; when temperature is increased, the fundamental band gap increases instead of decreases. This anomalous thermal dependence has also been observed recently in its monolayer counterpart. In this work, based on ab initio calculations, we present an explanation for this long known and yet not fully explained effect. We show that it arises from a combination of harmonic and lattice thermal expansion contributions, which are in fact highly interwined. We clearly narrow down the mechanisms that cause this gap opening by identifying the peculiar atomic vibrations that drive the anomaly. The final picture we give explains both the BP anomalous band gap opening and the frequency increase with increasing volume (tension effect).
Over-the-Horizon Anomalous VHF Propagation and Earthquake Precursors
NASA Astrophysics Data System (ADS)
Devi, M.; Barbara, A. K.; Ruzhin, Ya. Yu.; Hayakawa, M.
2012-09-01
The purpose of this paper is to review current activities for the identification of earthquake (EQ) precursors and their epicentres. Starting with a brief description on the background to approaches using ultra-low (ULF), extremely low (ELF), very low/low (VLF/LF), medium (MF), high (HF), very high frequency (VHF) etc. radio waves for short-term EQ prediction, the paper concentrates on those characteristics of anomalous VHF reception from frequency-modulation (FM) radio transmissions and broadcast television (TV) signals in relation to EQ precursors. The possible ways to identify an impending EQ and its epicentre position as defined and observed by workers from a variety of studies fall within the purview of the paper. In attempts to find pre-EQ energy exchange and coupling processes between the lithosphere and atmosphere, the paper highlights some relevant observations of surface latent heat flux, sonic detection and ranging (SODAR) echograms and LF propagation. Explanations on possible causes leading to such anomalous reception are reviewed with reported results in association with pre-seismic induced modifications to tropospheric and ionospheric parameters.
Large anomalous Hall effect in a half-Heusler antiferromagnet
NASA Astrophysics Data System (ADS)
Suzuki, T.; Chisnell, R.; Devarakonda, A.; Liu, Y.-T.; Feng, W.; Xiao, D.; Lynn, J. W.; Checkelsky, J. G.
2016-12-01
The quantum mechanical (Berry) phase of the electronic wavefunction plays a critical role in the anomalous and spin Hall effects, including their quantized limits. While progress has been made in understanding these effects in ferromagnets, less is known in antiferromagnetic systems. Here we present a study of antiferromagnet GdPtBi, whose electronic structure is similar to that of the topologically non-trivial HgTe (refs ,,), and where the Gd ions offer the possibility to tune the Berry phase via control of the spin texture. We show that this system supports an anomalous Hall angle ΘAH > 0.1, comparable to the largest observed in bulk ferromagnets and significantly larger than in other antiferromagnets. Neutron scattering measurements and electronic structure calculations suggest that this effect originates from avoided crossing or Weyl points that develop near the Fermi level due to a breaking of combined time-reversal and lattice symmetries. Berry phase effects associated with such symmetry breaking have recently been explored in kagome networks; our results extend this to half-Heusler systems with non-trivial band topology. The magnetic textures indicated here may also provide pathways towards realizing the topological insulating and semimetallic states predicted in this material class.
Constraints on mixed dark matter from anomalous strong lens systems
NASA Astrophysics Data System (ADS)
Kamada, Ayuki; Inoue, Kaiki Taro; Takahashi, Tomo
2016-07-01
Recently it has been claimed that the warm dark matter (WDM) model cannot at the same time reproduce the observed Lyman-α forests in distant quasar spectra and solve the small-scale issues in the cold dark matter (CDM) model. As an alternative candidate, it was shown that the mixed dark matter (MDM) model that consists of WDM and CDM can satisfy the constraint from Lyman-α forests and account for the "missing satellite problem" as well as the reported 3.5 keV anomalous x-ray line. We investigate observational constraints on the MDM model using strong gravitational lenses. We first develop a fitting formula for the nonlinear power spectra in the MDM model by performing N -body simulations and estimate the expected perturbations caused by line-of-sight structures in four quadruply lensed quasars that show anomaly in the flux ratios. Our analysis indicates that the MDM model is compatible with the observed anomaly if the mass fraction of the warm component is smaller than 0.47 at the 95% confidence level. The MDM explanation to the anomalous x-ray line and the small-scale issues is still viable even after this constraint is taken into account.
Lattice Monte Carlo simulation of Galilei variant anomalous diffusion
Guo, Gang; Bittig, Arne; Uhrmacher, Adelinde
2015-05-01
The observation of an increasing number of anomalous diffusion phenomena motivates the study to reveal the actual reason for such stochastic processes. When it is difficult to get analytical solutions or necessary to track the trajectory of particles, lattice Monte Carlo (LMC) simulation has been shown to be particularly useful. To develop such an LMC simulation algorithm for the Galilei variant anomalous diffusion, we derive explicit solutions for the conditional and unconditional first passage time (FPT) distributions with double absorbing barriers. According to the theory of random walks on lattices and the FPT distributions, we propose an LMC simulation algorithm and prove that such LMC simulation can reproduce both the mean and the mean square displacement exactly in the long-time limit. However, the error introduced in the second moment of the displacement diverges according to a power law as the simulation time progresses. We give an explicit criterion for choosing a small enough lattice step to limit the error within the specified tolerance. We further validate the LMC simulation algorithm and confirm the theoretical error analysis through numerical simulations. The numerical results agree with our theoretical predictions very well.
Identification of anomalous motion of thunderstorms using daily rainfall fields
NASA Astrophysics Data System (ADS)
Moral, Anna del; Llasat, María del Carmen; Rigo, Tomeu
2017-03-01
Most of the adverse weather phenomena in Catalonia (northeast Iberian Peninsula) are caused by convective events, which can produce heavy rains, large hailstones, strong winds, lightning and/or tornadoes. These thunderstorms usually have marked paths. However, their trajectories can vary sharply at any given time, completely changing direction from the path they have previously followed. Furthermore, some thunderstorms split or merge with each other, creating new formations with different behaviour. In order to identify the potentially anomalous movements that some thunderstorms make, this paper presents a two-step methodology using a database with 8 years of daily rainfall fields data for the Catalonia region (2008-2015). First, it classifies daily rainfall fields between days with "no rain", "non-potentially convective rain" and "potentially convective rain", based on daily accumulated precipitation and extension thresholds. Second, it categorises convective structures within rainfall fields and briefly identifies their main features, distinguishing whether there were any anomalous thunderstorm movements in each case. This methodology has been applied to the 2008-2015 period, and the main climatic features of convective and non-convective days were obtained. The methodology can be exported to other regions that do not have the necessary radar-based algorithms to detect convective cells, but where there is a good rain gauge network in place.
Anomalous topography on the continental shelf around Hudson Canyon
Knebel, H. J.
1979-01-01
Recent seismic-reflection data show that the topography on the Continental Shelf around Hudson Canyon is composed of a series of depressions having variable spacings (< 100 m to 2 km), depths (1-10 m), outlines, and bottom configurations that give the sea floor an anomalous "jagged" appearance in profile. The acoustic and sedimentary characteristics, the proximity to relict shores, and the areal distribution indicate that this rough topography is an erosional surface formed on Upper Pleistocene silty sands about 13,000 to 15,000 years ago by processes related to Hudson Canyon. The pronounced southward extension of the surface, in particular, may reflect a former increase in the longshore-current erosion capacity caused by the loss of sediments over the canyon. Modern erosion or nondeposition of sediments has prevented the ubiquitous sand sheet on the Middle Atlantic shelf from covering the surface. The "anomalous" topography may, in fact, be characteristic of areas near other submarine canyons that interrupt or have interrupted the longshore drift of sediments. ?? 1979.
Origin of anomalous water permeation through graphene oxide membrane.
Boukhvalov, Danil W; Katsnelson, Mikhail I; Son, Young-Woo
2013-08-14
Water inside the low-dimensional carbon structures has been considered seriously owing to fundamental interest in its flow and structures as well as its practical impact. Recently, the anomalous perfect penetration of water through graphene oxide membrane was demonstrated although the membrane was impenetrable for other liquids and even gases. The unusual auxetic behavior of graphene oxide in the presence of water was also reported. Here, on the basis of first-principles calculations, we establish atomistic models for hybrid systems composed of water and graphene oxides revealing the anomalous water behavior inside the stacked graphene oxides. We show that formation of hexagonal ice bilayer in between the flakes as well as melting transition of ice at the edges of flakes are crucial to realize the perfect water permeation across the whole stacked structures. The distance between adjacent layers that can be controlled either by oxygen reduction process or pressure is shown to determine the water flow thus highlighting a unique water dynamics in randomly connected two-dimensional spaces.
Osmotic generation of 'anomalous' fluid pressures in geological environments
Neuzii, C.E.
2000-01-01
Osmotic pressures are generated by differences in chemical potential of a solution across a membrane. But whether osmosis can have a significant effect on the pressure of fluids in geological environments has been controversial, because the membrane properties of geological media are poorly understood. 'Anomalous' pressures - large departures from hydrostatic pressure that are not explicable in terms of topographic or fluid-density effects are widely found in geological settings, and are commonly considered to result from processes that alter the pore or fluid volume, which in turn implies crustal changes happening at a rate too slow to observe directly. Yet if osmosis can explain some anomalies, there is no need to invoke such dynamic geological processes in those cases. Here I report results of a nine- year in situ measurement of fluid pressures and solute concentrations in shale that are consistent with the generation of large (up to 20 MPa) osmotic-pressure anomalies which could persist for tens of millions of years. Osmotic pressures of this magnitude and duration can explain many of the pressure anomalies observed in geological settings. The require, however, small shale porosity and large contrasts in the amount of dissolved solids in the pore waters - criteria that may help to distinguish between osmotic and crystal-dynamic origins of anomalous pressures.
Onset of anomalous diffusion from local motion rules
NASA Astrophysics Data System (ADS)
de Nigris, Sarah; Carletti, Timoteo; Lambiotte, Renaud
2017-02-01
Anomalous diffusion processes, in particular superdiffusive ones, are known to be efficient strategies for searching and navigation in animals and also in human mobility. One way to create such regimes are Lévy flights, where the walkers are allowed to perform jumps, the "flights," that can eventually be very long as their length distribution is asymptotically power-law distributed. In our work, we present a model in which walkers are allowed to perform, on a one-dimensional lattice, "cascades" of n unitary steps instead of one jump of a randomly generated length, as in the Lévy case, where n is drawn from a cascade distribution pn. We show that this local mechanism may give rise to superdiffusion or normal diffusion when pn is distributed as a power law. We also introduce waiting times that are power-law distributed as well and therefore the probability distribution scaling is steered by the two local distributions power-law exponents. As a perspective, our approach may engender a possible generalization of anomalous diffusion in context where distances are difficult to define, as in the case of complex networks, and also provide an interesting model for diffusion in temporal networks.
Anomalous photoelectric effect of a polycrystalline topological insulator film.
Zhang, Hongbin; Yao, Jiandong; Shao, Jianmei; Li, Hai; Li, Shuwei; Bao, Dinghua; Wang, Chengxin; Yang, Guowei
2014-07-29
A topological insulator represents a new state of quantum matter that possesses an insulating bulk band gap as well as a spin-momentum-locked Dirac cone on the surface that is protected by time-reversal symmetry. Photon-dressed surface states and light-induced surface photocurrents have been observed in topological insulators. Here, we report experimental observations of an anomalous photoelectric effect in thin films of Bi2Te3, a polycrystalline topological insulator. Under illumination with non-polarised light, transport measurements reveal that the resistance of the topological surface states suddenly increases when the polycrystalline film is illuminated. The resistance variation is positively dependent on the light intensity but has no relation to the applied electric field; this finding can be attributed to the gap opening of the surface Dirac cone. This observation of an anomalous photoelectric effect in polycrystalline topological insulators offers exciting opportunities for the creation of photodetectors with an unusually broad spectral range. Moreover, polycrystalline topological insulator films provide an attractive material platform for exploring the nature and practical application of topological insulators.
Petrology of Anomalous Mafic Achondrite Polymict Breccia Pasamonte
NASA Technical Reports Server (NTRS)
Mittlefehldt, D. W.; Berger, E. L.; Le, L.
2017-01-01
The most common asteroidal igneous meteorites are eucrite-type basalts and gabbros - rocks composed of ferroan pigeonite and augite, calcic plagioclase, silica, ilmenite, troilite, Ca-phosphate, chromite and Fe-metal [1]. These rocks are thought to have formed on a single asteroid, widely considered to be 4 Vesta, along with howardites and diogenites [1, 2]. High precision O-isotopic analyses have shown that some eucrites have small, well-resolved O-isotopic differences from the group mean [3-5]. These Oanomalous eucrites are thought to hail from asteroidal parents that are distinct from that of eucrites [5]. Three O-anomalous eucrites are PCA 82502, PCA 91007 (paired) and Pasamonte, all of which have the same O-isotopic composition [5, 6]. Our petrologic studies have shown that PCA 82502 and PCA 91007 have well-resolved anomalies in low-Ca pyroxene Fe/Mn compared to eucrites [6]. Divalent Mn and Fe are homologous species that do not greatly fractionate during igneous processes; mafic mineral Fe/Mn can be used to fingerprint parent object sources [7]. Previous petrological studies of Pasamonte [8-10] have not yielded sufficiently precise Fe/Mn ratios to allow distinction of anomalies of the scale of those found for the PCA basalts. We have begun petrological study of Pasamonte for comparison with our results on normal and anomalous eucrites [6], and to constrain its origin.
Anomalous Photoelectric Effect of a Polycrystalline Topological Insulator Film
Zhang, Hongbin; Yao, Jiandong; Shao, Jianmei; Li, Hai; Li, Shuwei; Bao, Dinghua; Wang, Chengxin; Yang, Guowei
2014-01-01
A topological insulator represents a new state of quantum matter that possesses an insulating bulk band gap as well as a spin-momentum-locked Dirac cone on the surface that is protected by time-reversal symmetry. Photon-dressed surface states and light-induced surface photocurrents have been observed in topological insulators. Here, we report experimental observations of an anomalous photoelectric effect in thin films of Bi2Te3, a polycrystalline topological insulator. Under illumination with non-polarised light, transport measurements reveal that the resistance of the topological surface states suddenly increases when the polycrystalline film is illuminated. The resistance variation is positively dependent on the light intensity but has no relation to the applied electric field; this finding can be attributed to the gap opening of the surface Dirac cone. This observation of an anomalous photoelectric effect in polycrystalline topological insulators offers exciting opportunities for the creation of photodetectors with an unusually broad spectral range. Moreover, polycrystalline topological insulator films provide an attractive material platform for exploring the nature and practical application of topological insulators. PMID:25069391
Quantum oscillations in mesoscopic rings and anomalous diffusion
NASA Astrophysics Data System (ADS)
Texier, Christophe; Montambaux, Gilles
2005-04-01
We consider the weak localization correction to the conductance of a ring connected to a network. We analyse the harmonics content of the Al'tshuler-Aronov-Spivak (AAS) oscillations and we show that the presence of wires connected to the ring is responsible for a behaviour different from the one predicted by AAS. The physical origin of this behaviour is the anomalous diffusion of Brownian trajectories around the ring, due to the diffusion in the wires. We show that this problem is related to the anomalous diffusion along the skeleton of a comb. We study in detail the winding properties of Brownian curves around a ring connected to an arbitrary network. Our analysis is based on the spectral determinant and on the introduction of an effective perimeter probing the different time scales. A general expression of this length is derived for arbitrary networks. More specifically we consider the case of a ring connected to wires, to a square network and to a Bethe lattice.
Anomalous diffusion and scaling in coupled stochastic processes
Bel, Golan; Nemenman, Ilya
2009-01-01
Inspired by problems in biochemical kinetics, we study statistical properties of an overdamped Langevin processes with the friction coefficient depending on the state of a similar, unobserved, process. Integrating out the latter, we derive the Pocker-Planck the friction coefficient of the first depends on the state of the second. Integrating out the latter, we derive the Focker-Planck equation for the probability distribution of the former. This has the fonn of diffusion equation with time-dependent diffusion coefficient, resulting in an anomalous diffusion. The diffusion exponent can not be predicted using a simple scaling argument, and anomalous scaling appears as well. The diffusion exponent of the Weiss-Havlin comb model is derived as a special case, and the same exponent holds even for weakly coupled processes. We compare our theoretical predictions with numerical simulations and find an excellent agreement. The findings caution against treating biochemical systems with unobserved dynamical degrees of freedom by means of standandard, diffusive Langevin descritpion.
The Occurrence of Anomalous Conductance Plateaus and Spin Textures in Quantum Point Contacts
NASA Astrophysics Data System (ADS)
Wan, J.; Cahay, M.; Debray, P.; Newrock, R.
2010-03-01
Recently, we used a NEGF formalism [1] to provide a theoretical explanation for the experimentally observed 0.5G0 (G0=2e^2/h) plateau in the conductance of side-gated quantum point contacts (QPCs) in the presence of lateral spin-orbit coupling (LSOC) [2]. We showed that the 0.5G0 plateau appears in the QPCs without any external magnetic field as a result of three ingredients: an asymmetric lateral confinement, a LSOC, and a strong electron-electron (e-e) interaction. In this report, we present the results of simulations for a wide range of QPC dimensions and biasing parameters showing that the same physics predicts the appearance of other anomalous plateaus at non-integer values of G0, including the well-known 0.7G0 anomaly. These features are related to a plethora of spin textures in the QPC that depend sensitively on material, device, biasing parameters, temperature, and the strength of the e-e interaction. [1] J. Wan, M. Cahay, P. Debray, and R.S. Newrock, Phys. Rev. B 80, 155440 (2009). [2] P. Debray, S.M. Rahman, J. Wan, R.S. Newrock, M. Cahay, A.T. Ngo, S.E. Ulloa, S.T. Herbert, M. Muhammad, and M. Johnson, Nature Nanotech. 4, 759 (2009).
Anomalous ultrafast dynamics of hot plasmonic electrons in nanostructures with hot spots.
Harutyunyan, Hayk; Martinson, Alex B F; Rosenmann, Daniel; Khorashad, Larousse Khosravi; Besteiro, Lucas V; Govorov, Alexander O; Wiederrecht, Gary P
2015-09-01
The interaction of light and matter in metallic nanosystems is mediated by the collective oscillation of surface electrons, called plasmons. After excitation, plasmons are absorbed by the metal electrons through inter- and intraband transitions, creating a highly non-thermal distribution of electrons. The electron population then decays through electron-electron interactions, creating a hot electron distribution within a few hundred femtoseconds, followed by a further relaxation via electron-phonon scattering on the timescale of a few picoseconds. In the spectral domain, hot plasmonic electrons induce changes to the plasmonic resonance of the nanostructure by modifying the dielectric constant of the metal. Here, we report on the observation of anomalously strong changes to the ultrafast temporal and spectral responses of these excited hot plasmonic electrons in hybrid metal/oxide nanostructures as a result of varying the geometry and composition of the nanostructure and the excitation wavelength. In particular, we show a large ultrafast, pulsewidth-limited contribution to the excited electron decay signal in hybrid nanostructures containing hot spots. The intensity of this contribution correlates with the efficiency of the generation of highly excited surface electrons. Using theoretical models, we attribute this effect to the generation of hot plasmonic electrons from hot spots. We then develop general principles to enhance the generation of energetic electrons through specifically designed plasmonic nanostructures that could be used in applications where hot electron generation is beneficial, such as in solar photocatalysis, photodetectors and nonlinear devices.
Children's Responses to Anomalous Scientific Data: How Is Conceptual Change Impeded?
ERIC Educational Resources Information Center
Chinn, Clark A.; Malhotra, Betina A.
2002-01-01
Four experiments with 4th, 5th, and 6th graders addressed conceptual change in response to anomalous data about empirical regularities in science. Impedance to conceptual change in response to anomalous data could potentially occur at any of four cognitive processes: observation, interpretation, generalization, or retention. In the four…
Cusp Anomalous Dimension in Maximally Supersymmetric Yang-Mills Theory at Strong Coupling
Basso, B.; Korchemsky, G. P.; Kotanski, J.
2008-03-07
We construct an analytical solution to the integral equation which is believed to describe logarithmic growth of the anomalous dimensions of high-spin operators in planar N=4 super Yang-Mills theory and use it to determine the strong coupling expansion of the cusp anomalous dimension.
Multi-crystal Anomalous Diffraction for Low-resolution Macromolecular Phasing
Q Liu; Z Zhang; W Hendrickson
2011-12-31
Multiwavelength anomalous diffraction (MAD) and single-wavelength anomalous diffraction (SAD) are the two most commonly used methods for de novo determination of macromolecular structures. Both methods rely on the accurate extraction of anomalous signals; however, because of factors such as poor intrinsic order, radiation damage, inadequate anomalous scatterers, poor diffraction quality and other noise-causing factors, the anomalous signal from a single crystal is not always good enough for structure solution. In this study, procedures for extracting more accurate anomalous signals by merging data from multiple crystals are devised and tested. SAD phasing tests were made with a relatively large (1456 ordered residues) poorly diffracting (d{sub min} = 3.5 {angstrom}) selenomethionyl protein (20 Se). It is quantified that the anomalous signal, success in substructure determination and accuracy of phases and electron-density maps all improve with an increase in the number of crystals used in merging. Structure solutions are possible when no single crystal can support structural analysis. It is proposed that such multi-crystal strategies may be broadly useful when only weak anomalous signals are available.
Rupture of an anomalous tendon slip as a cause of forearm pain.
O'Hara, J J; Stone, J H
1995-12-01
Rupture of an anomalous tendon slip between the FDS aponeurosis and FDP tendon to the ring finger was found in a young woman's forearm upon surgical exploration after months of forearm pain and disability. Excision of the anomalous slip resulted in quick and and complete recovery.
Scaling of local slopes, conservation laws, and anomalous roughening in surface growth.
López, Juan M; Castro, Mario; Gallego, Rafael
2005-04-29
We argue that symmetries and conservation laws greatly restrict the form of the terms entering the long wavelength description of growth models exhibiting anomalous roughening. This is exploited to show by dynamic renormalization group arguments that intrinsic anomalous roughening cannot occur in local growth models. However, some conserved dynamics may display superroughening if a given type of term is present.
Analyzing "Real-World" Anomalous Data after Experimentation with a Virtual Laboratory
ERIC Educational Resources Information Center
Toth, Eva Erdosne
2016-01-01
Developing effective pedagogies to help students examine anomalous data is critical for the education of the next generation of scientists and engineers. By definition anomalous data do not concur with prior knowledge, theories and expectations. Such data are the common outcome of empirical investigation in hands-on laboratories (HOLs). These…
Thickness Dependence of the Quantum Anomalous Hall Effect in Magnetic Topological Insulator Films.
Feng, Xiao; Feng, Yang; Wang, Jing; Ou, Yunbo; Hao, Zhenqi; Liu, Chang; Zhang, Zuocheng; Zhang, Liguo; Lin, Chaojing; Liao, Jian; Li, Yongqing; Wang, Li-Li; Ji, Shuai-Hua; Chen, Xi; Ma, Xucun; Zhang, Shou-Cheng; Wang, Yayu; He, Ke; Xue, Qi-Kun
2016-08-01
The evolution of the quantum anomalous Hall effect with the thickness of Cr-doped (Bi,Sb)2 Te3 magnetic topological insulator films is studied, revealing how the effect is caused by the interplay of the surface states, band-bending, and ferromagnetic exchange energy. Homogeneity in ferromagnetism is found to be the key to high-temperature quantum anomalous Hall material.
Conceptual Change and Anomalous Data: A Case Study in the Domain of the Natural Sciences.
ERIC Educational Resources Information Center
Limon, Margarita; Carretero, Mario
1997-01-01
Reports on an experiment that explored novice learners' responses to anomalous data (new data that contradict previous beliefs). Secondary education students were given both anomalous and confirmatory data concerning various theories about the origin of life on earth. Statistical data reveal their level of awareness of the contradictions. (MJP)
Transport equations for subdiffusion with nonlinear particle interaction.
Straka, P; Fedotov, S
2015-02-07
We show how the nonlinear interaction effects 'volume filling' and 'adhesion' can be incorporated into the fractional subdiffusive transport of cells and individual organisms. To this end, we use microscopic random walk models with anomalous trapping and systematically derive generic non-Markovian and nonlinear governing equations for the mean concentrations of the subdiffusive cells or organisms. We uncover an interesting interaction between the nonlinearities and the non-Markovian nature of the transport. In the subdiffusive case, this interaction manifests itself in a nontrivial combination of nonlinear terms with fractional derivatives. In the long time limit, however, these equations simplify to a form without fractional operators. This provides an easy method for the study of aggregation phenomena. In particular, this enables us to show that volume filling can prevent "anomalous aggregation," which occurs in subdiffusive systems with a spatially varying anomalous exponent.
Progress toward a search for anomalous spin-mass couplings with a dual-isotope rubidium magnetometer
NASA Astrophysics Data System (ADS)
Valdez, Julian; Lacey, Ian; Peregrinaramirez, Rodrigo; Delcheva, Delyana; Jacome, L. R.; Kimball, Derek
2010-10-01
A coupling between spin and mass can arise from new spin-0 or spin-1 force-mediating particles or in non-standard gravity with scalar or vector components in addition to the usual tensor interaction. We report on progress toward a search for anomalous couplings between the mass of the earth and Rb spins. In the experiment, a natural isotopic mixture of Rb atoms is contained in an antirelaxation-coated cell. The atomic spins are polarized via laser optical pumping and spin precession is measured in both isotopes using optical rotation. The experiment is particularly sensitive to spin-mass interactions of the proton. We discuss the sensitivity of our experimental scheme and strategies for control of several important systematic effects such as differential light shifts, collisional frequency shifts, and frequency shifts due to the rotation of the earth.
Anomalous transport in fracture networks: field scale experiments and modelling
NASA Astrophysics Data System (ADS)
Kang, P. K.; Le Borgne, T.; Bour, O.; Dentz, M.; Juanes, R.
2012-12-01
Anomalous transport is widely observed in different settings and scales of transport through porous and fractured geologic media. A common signature of anomalous transport is the late-time power law tailing in breakthrough curves (BTCs) during tracer tests. Various conceptual models of anomalous transport have been proposed, including multirate mass transfer, continuous time random walk, and stream tube models. Since different conceptual models can produce equally good fits to a single BTC, tracer test interpretation has been plagued with ambiguity. Here, we propose to resolve such ambiguity by analyzing BTCs obtained from both convergent and push-pull flow configurations at two different fracture planes. We conducted field tracer tests in a fractured granite formation close to Ploemeur, France. We observe that BTC tailing depends on the flow configuration and the injection fracture. Specifically the tailing disappears under push-pull geometry, and when we injected at a fracture with high flux (Figure 1). This indicates that for this fractured granite, BTC tailing is controlled by heterogeneous advection and not by matrix diffusion. To explain the change in tailing behavior for different flow configurations, we employ a simple lattice network model with heterogeneous conductivity distribution. The model assigns random conductivities to the fractures and solves the Darcy equation for an incompressible fluid, enforcing mass conservation at fracture intersections. The mass conservation constraint yields a correlated random flow through the fracture system. We investigate whether BTC tailing can be explained by the spatial distribution of preferential flow paths and stagnation zones, which is controlled by the conductivity variance and correlation length. By combining the results from the field tests and numerical modeling, we show that the reversibility of spreading is a key mechanism that needs to be captured. We also demonstrate the dominant role of the injection
Anomalous Centrifugal Distortion in HDO and Spectroscopic Data Bases
NASA Astrophysics Data System (ADS)
Coudert, L. H.
2015-06-01
The HDO molecule is important from the atmospheric point of view as it can be used to study the water cycle in the earth atmosphere. It is also interesting from the spectroscopic point of view as it displays an anomalous centrifugal distortion similar to that of the normal species H_2O. A model developed to treat the anomalous distortion in HDO should account for the fact that it lacks a two-fold axis of symmetry. A new treatment aimed at the calculation of the rovibrational energy of the HDO molecule and allowing for anomalous centrifugal distortion effects has been developed. It is based on an effective Hamiltonian in which the large amplitude bending ν_2 mode and the overall rotation of the molecule are treated simultaneously. Due to the lack of a two-fold axis of symmetry, this effective Hamiltonian contains terms arising from the non-diagonal component of the inertia tensor and from the Coriolis-coupling between the large amplitude bending ν_2 mode and the overall rotation of the molecule. This new treatment has been used to perform a line position analysis of a large body of infrared, microwave, and hot water vapor data involving the ground and (010) states up to J=22. For these 4413 data, a unitless standard deviation of 1.1 was achieved. A line intensity analysis was also carried out and allowed us to reproduce the strength of 1316 transitions^c with a unitless standard deviation of 1.1. In the talk, the new theoretical approach will be presented. The results of both analyses will be discussed and compared with those of a previous investigation. The new spectroscopic data base built will be compared with HITRAN 2012. Herbin et al., Atmos. Chem. Phys.~9 (2009) 9433; and Schneider and Hase, Atmos. Chem. Phys.~ 11 (2011) 11207. Coudert, Wagner, Birk, Baranov, Lafferty, and Flaud, J. Molec. Spectrosc.~251 (2008) 339. Johns, J. Opt. Soc. Am. B~2 (1985) 1340 Toth, J. Molec. Spectrosc.~162 (1993) 20 Paso and Horneman, J. Opt. Soc. Am. B~12 (1995) 1813 Toth, J
Hydrophobic hydration and the anomalous partial molar volumes in ethanol-water mixtures
Tan, Ming-Liang; Te, Jerez; Cendagorta, Joseph R.; Miller, Benjamin T.; Brooks, Bernard R.; Ichiye, Toshiko
2015-02-14
The anomalous behavior in the partial molar volumes of ethanol-water mixtures at low concentrations of ethanol is studied using molecular dynamics simulations. Previous work indicates that the striking minimum in the partial molar volume of ethanol V{sub E} as a function of ethanol mole fraction X{sub E} is determined mainly by water-water interactions. These results were based on simulations that used one water model for the solute-water interactions but two different water models for the water-water interactions. This is confirmed here by using two more water models for the water-water interactions. Furthermore, the previous work indicates that the initial decrease is caused by association of the hydration shells of the hydrocarbon tails, and the minimum occurs at the concentration where all of the hydration shells are touching each other. Thus, the characteristics of the hydration of the tail that cause the decrease and the features of the water models that reproduce this type of hydration are also examined here. The results show that a single-site multipole water model with a charge distribution that mimics the large quadrupole and the p-orbital type electron density out of the molecular plane has “brittle” hydration with hydrogen bonds that break as the tails touch, which reproduces the deep minimum. However, water models with more typical site representations with partial charges lead to flexible hydration that tends to stay intact, which produces a shallow minimum. Thus, brittle hydration may play an essential role in hydrophobic association in water.
NASA Astrophysics Data System (ADS)
Lin, Jian; Liu, Jiaming; Zhang, Hao; Li, Wenxiu; Zhao, Lu; Jin, Junjie; Huang, Anping; Zhang, Xiaofu; Xiao, Zhisong
2016-12-01
Rigorous expressions of resonant frequency shift (RFS) in anomalous dispersion enhanced resonant optical gyroscopes (ADEROGs) are deduced without making approximation, which provides a precise theoretical guidance to achieve ultra-sensitive ADEROGs. A refractive index related modification factor is introduced when considering special theory of relativity (STR). We demonstrate that the RFS will not be ”infinitely large” by using critical anomalous dispersion (CAD) and negative modification does not exist, which make the mechanism of anomalous dispersion enhancement clear and coherent. Although step change of RFS will happen when the anomalous dispersion condition varies, the amplification of RFS is limited by attainable variation of refractive index in practice. Moreover, it is shown that the properties of anomalous dispersion will influence not only the amplification of RFS, but also the detection range of ADEROGs.
Lin, Jian; Liu, Jiaming; Zhang, Hao; Li, Wenxiu; Zhao, Lu; Jin, Junjie; Huang, Anping; Zhang, Xiaofu; Xiao, Zhisong
2016-01-01
Rigorous expressions of resonant frequency shift (RFS) in anomalous dispersion enhanced resonant optical gyroscopes (ADEROGs) are deduced without making approximation, which provides a precise theoretical guidance to achieve ultra-sensitive ADEROGs. A refractive index related modification factor is introduced when considering special theory of relativity (STR). We demonstrate that the RFS will not be ”infinitely large” by using critical anomalous dispersion (CAD) and negative modification does not exist, which make the mechanism of anomalous dispersion enhancement clear and coherent. Although step change of RFS will happen when the anomalous dispersion condition varies, the amplification of RFS is limited by attainable variation of refractive index in practice. Moreover, it is shown that the properties of anomalous dispersion will influence not only the amplification of RFS, but also the detection range of ADEROGs. PMID:27941897
Lin, Jian; Liu, Jiaming; Zhang, Hao; Li, Wenxiu; Zhao, Lu; Jin, Junjie; Huang, Anping; Zhang, Xiaofu; Xiao, Zhisong
2016-12-12
Rigorous expressions of resonant frequency shift (RFS) in anomalous dispersion enhanced resonant optical gyroscopes (ADEROGs) are deduced without making approximation, which provides a precise theoretical guidance to achieve ultra-sensitive ADEROGs. A refractive index related modification factor is introduced when considering special theory of relativity (STR). We demonstrate that the RFS will not be "infinitely large" by using critical anomalous dispersion (CAD) and negative modification does not exist, which make the mechanism of anomalous dispersion enhancement clear and coherent. Although step change of RFS will happen when the anomalous dispersion condition varies, the amplification of RFS is limited by attainable variation of refractive index in practice. Moreover, it is shown that the properties of anomalous dispersion will influence not only the amplification of RFS, but also the detection range of ADEROGs.
Precise quantization of anomalous Hall effect near zero magnetic field
NASA Astrophysics Data System (ADS)
Bestwick, Andrew; Fox, Eli; Kou, Xufeng; Pan, Lei; Wang, Kang; Goldhaber-Gordon, David
2015-03-01
The quantum anomalous Hall effect (QAHE) has recently been of great interest due to its recent experimental realization in thin films of Cr-doped (Bi, Sb)2Te3, a ferromagnetic 3D topological insulator. The presence of ferromagnetic exchange breaks time-reversal symmetry, opening a gap in the surface states, but gives rise to dissipationless chiral conduction at the edge of a magnetized film. Ideally, this leads to vanishing longitudinal resistance and Hall resistance quantized to h /e2 , where h is Planck's constant and e is the electron charge, but perfect quantization has so far proved elusive. Here, we study the QAHE in the limit of zero applied magnetic field, and measure Hall resistance quantized to within one part per 10,000. Deviation from quantization is due primarily to thermally activated carriers, which can be nearly eliminated through adiabatic demagnetization cooling. This result demonstrates an important step toward dissipationless electron transport in technologically relevant conditions.
Methodological approaches in estimating anomalous geochemical field structure
NASA Astrophysics Data System (ADS)
Gavrilov, R.; Rudmin, M.
2015-02-01
Mathematical statistic methods were applied to analyze the core samples from vertical expendable wells in Chertovo Koryto gold ore field. The following methods were used to analyse gold in samples: assay tests and atomic absorption method (AAS), while emission spectrum semiquantative method was applied to identify traces. The analysis of geochemical association distribution in one central profile demonstrated that bulk metasomatic aureoles are characteristic of concentric zonal structure. The distribution of geochemical associations is correlated to the hydrothermal stages of mineral formation identified in this deposit. It was proved that the processed geochemical data by factor and cluster analyses provided additional information on the anomalous geochemical field structure in gold- bearing black-shale strata. Such methods are effective tools in interpretating specific features of geochemical field structures in analogous potential ore-bearing areas.
Tuning giant anomalous Hall resistance ratio in perpendicular Hall balance
Zhang, J. Y.; Yang, G.; Wang, S. G. E-mail: ghyu@mater.ustb.edu.cn; Liu, J. L.; Wang, R. M.; Amsellem, E.; Kohn, A.; Yu, G. H. E-mail: ghyu@mater.ustb.edu.cn
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.
Anomalous polarization conversion in arrays of ultrathin ferromagnetic nanowires
NASA Astrophysics Data System (ADS)
Stashkevich, Andrey A.; Roussigné, Yves; Poddubny, Alexander N.; Chérif, S.-M.; Zheng, Y.; Vidal, Franck; Yagupov, Ilya V.; Slobozhanyuk, Alexei P.; Belov, Pavel A.; Kivshar, Yuri S.
2015-12-01
We study the optical properties of arrays of ultrathin cobalt nanowires by means of the Brillouin scattering of light on magnons. We employ the Stokes/anti-Stokes scattering asymmetry to probe the circular polarization of a local electric field induced inside nanowires by linearly polarized light waves. We observe the anomalous polarization conversion of the opposite sign than that in a bulk medium or thick nanowires with a great enhancement of the degree of circular polarization attributed to the unconventional refraction in a nanowire medium. A rigorous simulation of the electric field polarization as a function of the wire diameter and spacing reveals the reversed polarization for a thin sparse wire array, in full quantitative agreement with experimental results.
Shielding at a distance due to anomalous resonance
NASA Astrophysics Data System (ADS)
Yu, Sanghyeon; Lim, Mikyoung
2017-03-01
A cylindrical plasmonic structure with a concentric core exhibits an anomalous localized resonance which results in cloaking effects. Here we show that if the structure has an eccentric core, a new kind of shielding effect can happen. In contrast to conventional shielding devices, our proposed structure can block the effect of external electrical sources, even in a region which is not enclosed by any conducting materials. In fact, the shielded region is located at a distance from the device. We analytically investigate this phenomenon by using the Möbius transformation, through which an eccentric annulus is transformed into a concentric one. We also present several numerical examples. This work is supported by the Korean Ministry of Science, ICT and Future Planning through NRF grant nos. 2013R1A1A3012931 (for ML) and 2016R1A2B4014530 (for ML).
Experimental demonstration of anomalous Floquet topological insulator for sound.
Peng, Yu-Gui; Qin, Cheng-Zhi; Zhao, De-Gang; Shen, Ya-Xi; Xu, Xiang-Yuan; Bao, Ming; Jia, Han; Zhu, Xue-Feng
2016-11-11
Time-reversal invariant topological insulator is widely recognized as one of the fundamental discoveries in condensed matter physics, for which the most fascinating hallmark is perhaps a spin-based topological protection, the absence of scattering of conduction electrons with certain spins on matter surface. Recently, it has created a paradigm shift for topological insulators, from electronics to photonics, phononics and mechanics as well, bringing about not only involved new physics but also potential applications in robust wave transport. Despite the growing interests in topologically protected acoustic wave transport, T-invariant acoustic topological insulator has not yet been achieved. Here we report experimental demonstration of anomalous Floquet topological insulator for sound: a strongly coupled metamaterial ring lattice that supports one-way propagation of pseudo-spin-dependent edge states under T-symmetry. We also demonstrate the formation of pseudo-spin-dependent interface states due to lattice dislocations and investigate the properties of pass band and band gap states.
Consistent high-energy constraints in the anomalous QCD sector
NASA Astrophysics Data System (ADS)
Roig, Pablo; Sanz Cillero, Juan José
2014-06-01
The anomalous < VVP > Green function and related form-factors (π0 →γ*γ* and τ- →X-ντ vector form-factors, with X- = (KKπ)-, φ- γ, (φV)-) are analyzed in this letter in the large-NC limit. Within the single (vector and pseudoscalar) resonance approximation and the context of Resonance Chiral Theory, we show that all these observables overdetermine in a consistent way a unique set of compatible high-energy constraints for the resonance couplings. This result is in agreement with analogous relations found in the even intrinsic-parity sector of QCD like, e.g., FV2 = 3F2. The antisymmetric tensor formalism is considered for the spin-one resonance fields. Finally, we have also worked out and provide here the relation between the two bases of odd intrinsic-parity Lagrangian operators commonly employed in the literature.
Anomalous precession of planets for a Weyl conformastatic solution
NASA Astrophysics Data System (ADS)
Capistrano, Abraão J. S.; Peñagos, Joice A. M.; Alárcon, Manuel S.
2016-12-01
In this article, we investigate the anomalous precession of planets in the nearly Newtonian gravitational regime. This limit is obtained by application of the slow motion condition to the geodesic equations without altering the geodesic deviation equations. Using a non-standard expression for the perihelion advance from the Weyl conformastatic vacuum solution as a model, we can describe the anomaly in planetary precession compared with different observational data, consisting of ephemerides of planets and the Moon (EPM2008 and EPM2011) and Fienga et al.'s planetary and lunar ephemeris (INPOP10a). As a result, using the Levenberg-Marquardt algorithm and calculating the related χ-squared statistic, we find that the anomaly is statistically irrelevant, in accordance with the INPOP10a observations. As a complement to this work, we also perform an application to the relativistic precession of giant planets using observational data calibrated with EPM2011.
Deviation of the statistical fluctuation in heterogeneous anomalous diffusion
NASA Astrophysics Data System (ADS)
Itto, Yuichi
2016-11-01
The exponent of anomalous diffusion of virus in cytoplasm of a living cell is experimentally known to fluctuate depending on localized areas of the cytoplasm, indicating heterogeneity of diffusion. In a recent paper (Itto, 2012), a maximum-entropy-principle approach has been developed in order to propose an Ansatz for the statistical distribution of such exponent fluctuations. Based on this approach, here the deviation of the statistical distribution of the fluctuations from the proposed one is studied from the viewpoint of Einstein's theory of fluctuations (of the thermodynamic quantities). This may present a step toward understanding the statistical property of the deviation. It is shown in a certain class of small deviations that the deviation obeys the multivariate Gaussian distribution.
Anomalous volatility scaling in high frequency financial data
NASA Astrophysics Data System (ADS)
Nava, Noemi; Di Matteo, T.; Aste, Tomaso
2016-04-01
Volatility of intra-day stock market indices computed at various time horizons exhibits a scaling behaviour that differs from what would be expected from fractional Brownian motion (fBm). We investigate this anomalous scaling by using empirical mode decomposition (EMD), a method which separates time series into a set of cyclical components at different time-scales. By applying the EMD to fBm, we retrieve a scaling law that relates the variance of the components to a power law of the oscillating period. In contrast, when analysing 22 different stock market indices, we observe deviations from the fBm and Brownian motion scaling behaviour. We discuss and quantify these deviations, associating them to the characteristics of financial markets, with larger deviations corresponding to less developed markets.
Experimental demonstration of anomalous Floquet topological insulator for sound
NASA Astrophysics Data System (ADS)
Peng, Yu-Gui; Qin, Cheng-Zhi; Zhao, De-Gang; Shen, Ya-Xi; Xu, Xiang-Yuan; Bao, Ming; Jia, Han; Zhu, Xue-Feng
2016-11-01
Time-reversal invariant topological insulator is widely recognized as one of the fundamental discoveries in condensed matter physics, for which the most fascinating hallmark is perhaps a spin-based topological protection, the absence of scattering of conduction electrons with certain spins on matter surface. Recently, it has created a paradigm shift for topological insulators, from electronics to photonics, phononics and mechanics as well, bringing about not only involved new physics but also potential applications in robust wave transport. Despite the growing interests in topologically protected acoustic wave transport, T-invariant acoustic topological insulator has not yet been achieved. Here we report experimental demonstration of anomalous Floquet topological insulator for sound: a strongly coupled metamaterial ring lattice that supports one-way propagation of pseudo-spin-dependent edge states under T-symmetry. We also demonstrate the formation of pseudo-spin-dependent interface states due to lattice dislocations and investigate the properties of pass band and band gap states.
Cosmic ray anisotropy in fractional differential models of anomalous diffusion
Uchaikin, V. V.
2013-06-15
The problem of galactic cosmic ray anisotropy is considered in two versions of the fractional differential model for anomalous diffusion. The simplest problem of cosmic ray propagation from a point instantaneous source in an unbounded medium is used as an example to show that the transition from the standard diffusion model to the Lagutin-Uchaikin fractional differential model (with characteristic exponent {alpha} = 3/5 and a finite velocity of free particle motion), which gives rise to a knee in the energy spectrum at 10{sup 6} GeV, increases the anisotropy coefficient only by 20%, while the anisotropy coefficient in the Lagutin-Tyumentsev model (with exponents {alpha} = 0.3 and {beta} = 0.8, a long stay of particles in traps, and an infinite velocity of their jumps) is close to one. This is because the parameters of the Lagutin-Tyumentsev model have been chosen improperly.